5-12 November 1996
New England Conference Center
University of New Hampshire
Durham, NH 03874
III. Working Group Reports
APPENDIX I. Meeting Agenda
APPENDIX II. List of Workshop Participants.
APPENDIX III. U.S. GLOBEC Phase I Physical Oceanographic Measurements.
The U.S. GLOBEC Georges Bank Scientific Investigators' Workshop was
held from 5 to 12 November 1996 at the New England Center of the
University of New Hampshire. This was an intensive, eight day, data
analysis and synthesis workshop. The format of the workshop was
informal and involved use of networked computers supplied by
individual investigators. The goals of the workshop were to:
In the words of Cabell Davis:
"... the purpose of the meeting is not to present synthesized results, but to actually do the synthesis at the meeting, while working collaboratively."
In addition, a new executive committee was elected into office
during the course of the workshop.
The workshop began during late afternoon of 5 November 1996 after most of the participants had completed setting up their computers on the local network. Opening remarks by Peter Wiebe described the objectives and goals of the workshop, reviewed the agenda and structure of the workshop, and presented some ideas about possible products resulting from activities at the workshop (a workshop report, collections of papers to be submitted for one or more special volumes, etc). Participants were encouraged to think about the targeting of upcoming scientific meetings that could be used as forums to present the results of the workshop and new findings resulting from this research program. Three meetings described as appropriate forums were:
The latter two were cited as providing the best forums primarily as a result of their timing (the TOS meeting comes in the middle of the very intense 1997 field season), and the nature of the scientific communities that would be attending the meetings. The ICES Annual Scientific Meeting provides a special opportunity for GLOBEC scientists working on Georges Bank to present and compare their research findings with GLOBEC scientists working in the eastern North Atlantic Ocean. A special theme session entitled "GLOBEC: Results from Inter-Disciplinary Programs in the North Atlantic" has been officially approved by ICES. Additional details about the general call for papers will be issued about mid-January 1997. The Ocean Science Meeting has traditionally been an excellent forum for group presentations to the U.S. oceanographic community and it comes at a time when much of the work from the first years of the Georges Bank field and modeling work should be ready for national scrutiny.
Discussion then focused upon defining the disciplinary and interdisciplinary working groups in order to get the workshop running. The following disciplinary groups were suggested:
The following interdisciplinary topics were suggested for group discussions.
On Day 2 (Wednesday), the meeting started with a plenary session (chaired by P. Wiebe) to review the disciplinary session topics and to select the chairman and Rapporteurs for each group. There were three principal working groups formed along disciplinary lines, a physical oceanography (PO) working group which addressed a number of different topics, a predation working group, and a combined vital rates/population distribution and dynamics working group. Bob Beardsley gave a short description of the PO group session organization prior to the groups breaking out in the working group sessions. The plan presented was to discuss physical data collected on Wednesday, modeling the physical data on Thursday, and modeling of the coupled physics and biology on Friday. For the first full day's discussions, the following groups met:
|Phase I PO Results Group
||Bob Beardsley (Chair), David Mountain (Rapporteur)|
|Predation Group||Larry Madin (Chair), Erich Horgan (Rapporteur)|
|Vital Rates/Population Distribution and Dynamics Group||Ted Durbin & Dian Gifford (Chairs), Charles Miller (Rapporteur)|
||David Mountain (Rapporteur)|
|Slope Water Intrusions||Jim Irish (Rapporteur)|
|Stratification||Ken Brink (Rapporteur)|
In the afternoon, a mini-lecture series was begun (the first of four) which was titled "Setting the context - Modeling activities in the Georges Bank Program". Dan Lynch presented an overview of the modeling activities in the program.
The goals of the modeling activity are to produce and make generally available the following:
The status quo as of the end of Phase I includes separate emphases on the climatological circulation on real topography and on idealized process studies. Larval fish modeling has been used to explore the biophysical linkages among the circulation, trophodynamics, and turbulent mixing. Most coupled studies have been in the context of climatological mean conditions; there has also been exploration of coupled response to wind events and to inter-annual variability.
During Phase II, projects funded will emphasize the following:
The Spatially Explicit Ecosystem Model which is emerging has the following character. There will be a detailed Eulerian description, on realistic topography, of the following:
Individual-Based Models for Larval Fish will be transported through this simulated biophysical environment; these models will integrate Lagrangian life histories for individual organisms in terms of:
Dan Lynch's overview was followed by short talks by:
|Chris Naimie||Modeling focused on the climatological environment.|
|Dave Greenberg||A regional modeling perspective involving Hamilton Bank off Labrador to southwest of Georges Bank and including the Gulf of Maine.|
|Francisco Werner||Coupled physical-fish larvae modeling.||Charles Hannah||Supply pathways of particles onto Georges Bank.||Dan Lynch||Calanus finmarchicus population dynamics.||Dennis McGillicuddy||Simulation of Pseudocalanus population dynamics on Georges Bank.||Changsheng Chen||2D modeling of coupled physical and biology (NPZ) structure on Georges Bank.||Glenn Flierl||Empirical Orthogonal Function (EOF) simplification of populations dynamics.||Mohammad Iskanderani||Modeling the far-field boundaries - coupling the coastal model with a spectral element Basin Model.||Craig Lewis||Affects of wind events on Georges Bank.|
After a short plenary session at the beginning of Day 3 (Thursday), a mix of old and new groups again set to work. The PO Working Group focused on Physics modeling with Bob Beardsley, Chairman, and Charlie Flagg, Rapporteur, for the morning session, and Peter Smith, Chairman, and Bob Houghton, Rapporteur, for the afternoon session. The two biological groups continued to meet as well. The afternoon mini-lecture was titled "Biological structure of the target species and their rate processes on the Bank during 1995". Ted Durbin presented an overview of the distribution and dynamics of Calanus finmarchicus on the Bank in 1995 followed by a series of short talks on zooplankton by:
|Bob Campbell||Growth rates of Calanus.||Melissa Wagner||RNA/DNA ratios in Calanus.||Jeff Runge||Egg production rates of Calanus in the 1995 broad-scale time series.||Charlie Miller||Calanus tooth development as an indicator of growth dynamics on the Bank.||Ann Bucklin||Pattern of genetic variability in Calanus in the western north Atlantic as compared to other planktonic species.||Larry Madin||1995 target species predator fields on Georges Bank.||Bill Michaels||The 1995 COP predator studies on Georges Bank.||Lew Incze||The larval fish prey fields in relationship to small-scale turbulent fields.||Scott Gallager||Feeding behavior of larval cod.||Elaine Caldarone||Year to year variation in the RNA/DNA ratios of larval cod and haddock.||Cabell Davis||VPR images of a section through a shelf/Slope Water entrainment feature caused by a warm-core ring.||Carin Ashjian||VPR images of the physical and biological cross-bank structure.|
Short reports by the group leaders from the previous days sessions were presented during the morning plenary session on Day 4 (Friday). These were followed by the continued meeting of some of the current groups and several of the interdisciplinary groups. These were: a morning working group on modeling the fish which was chaired by Dan Lynch with Chris Naimie as Rapporteur; an afternoon working group on mapping broad-scale distributions taking into account the flow field which Dan Lynch chaired with Chris Naimie as Rapporteur; an afternoon working Group on Drifters which was chaired by Dick Limeburner with Charles Hannah as Rapporteur.
The afternoon mini-lecture series consisted of presentations on various topics on the Physical Oceanography of Georges Bank by:
|Charles Hannah||Large Scale Inter-decadal variability.|| Bob Houghton
|Gulf-scale inter-annual variability.||Bob Beardsley||1994-95 Georges Bank southern flank stratification.|| Jim Irish
|Slope Water intrusions and Scotian Shelf crossovers.|| Dick Limeburner
|Drifter observations and data/model comparisons.||Dan Lynch||Data assimilation and hind-casting.|
This session was Rapporteured by Glenn Flierl and summaries of the talks are given later in this report.
On Day 5 (Saturday), after brief working group reports at a plenary session, the morning working group focused on modeling the zooplankton. Ted Durbin and Dan Lynch co-chaired the session and Cisco Werner was the Rapporteur. The afternoon was spent by individuals working in small informal groups.
The principal activity on the morning and afternoon of Day 6 (Sunday) was the reviewing of plans for the 1997 field program. This started as a plenary session chaired by Peter Wiebe in which the cruise schedule was presented and Chief Scientists for the broad-scale cruises were selected (see Table 2 in the introduction to Section IV). The Chief scientists of the process cruises presented their plans for each cruise. A summary of the plans for the cruises are provided in Section IV below. The afternoon was devoted to smaller groups working out the details of the process cruises and the coordination of joint ship operations. In order to provide a complete picture of the plans for the cruises now scheduled to take place, included in the description of the cruise plans presented below is a description of a broad-scale cruise meeting that took place a couple of weeks after the workshop.
There were two general sessions on Day 7 (Monday). In the morning there was an open discussion of ways to improve the JGOFS data and information base structure and its usefulness. This produced a number of suggestions that are described in more detail below. In the afternoon, there was a general discussion of the planning required for Phase III of the U.S. GLOBEC Georges Bank Program.
Finally, on the morning of Day 8 (Tuesday), the election results were presented to the workshop participants. The election slate was finalized on the evening of 7 November. Voting began on the morning of 8 November (via a ballot and email) and ceased at noon on November 11. As of November 12, 1996 the new executive committee has the following members:
|Bob Beardsley||Woods Hole Oceanographic Institution||Jim Bisagni||National Marine Fisheries Service, Narragansett||Ted Durbin||University of Rhode Island||Scott Gallager||Woods Hole Oceanographic Institution||Greg Lough||National Marine Fisheries Service, Woods Hole||Dan Lynch||Dartmouth College||Larry Madin||Woods Hole Oceanographic Institution||David Mountain||National Marine Fisheries Service, Woods Hole||Peter Wiebe||Woods Hole Oceanographic Institution||Karen Wishner||University of Rhode Island|
At the EXCO meeting after the workshop held on 6 December, Peter Wiebe was elected Chairman and David Mountain was elected Rapporteur.
Computers were very much in evidence during the workshop. Participants were encouraged to bring their computers with them to the workshop to aid in data sharing and synthesis. All computers could easily connect to the internet via 10 Mb/second, 10BaseT connections and 33 PC's, Macintosh, and Unix-based computers were brought to the workshop, with 28 of them connected to the Internet.
In addition to accessing the U.S. GLOBEC Georges Bank on-line database via the Web, participants were able to see several on-line data access and display demonstrations, access a local laser and color printer, use resources from their home organizations (e.g. using ftp and X-Windows), and keep in touch via email. It was not unusual to see investigators working on their computers until the conference room facilities closed down for the night at 2300.
This ready access to on-line data and information, provided by
the large number of computers, facilitated the exchange of data and
ideas; and fostered the opportunities for collaboration and data
III. Working Group Reports
The following is a summary of the working group activities
prepared by the Rapporteurs of each working group. First are the
disciplinary working group reports followed by the interdisciplinary
working group reports.
Physical Oceanography General Session
Wednesday morning November 6.
Robert Beardsley (Chairman), David Mountain (Rapporteur)
The physical oceanographers met as a group for the first morning
session. Each PI or group of PI's made a short presentation to
indicate areas of interest/objectives in the program, data collected
and its status, and selected interesting findings. A table of the
existing physical data and its current status was compiled during
the workshop (Appendix III).
Broad-scale hydrography (David Mountain and Maureen Taylor): The objectives of the sampling are to provide a historic context for hydrographic conditions observed during the program period, to identify inter-annual variability, and to investigate event scale intrusions of water onto the Bank - most notably from the Scotian Shelf and the Slope Water region south of the Bank. Hydrographic data have been collected on six survey cruises in 1995 and six in 1996. The data processing is complete and the data are available through the GLOBEC Data Management System.
Noteworthy observations in 1995 were a large cross-over event of Scotian Shelf water in March and a Slope Water intrusion over much of the southern flank of the Bank in May. No similar intrusions were seen in 1996. The salinity of the waters in the region were considerably lower throughout the 1996 season in comparison to 1995.
Oxygen isotope data (Bob Houghton): Water samples for oxygen isotope (18O) have been collected on both broad-scale surveys and cruises by the Bedford Institute of Oceanography (BIO) as part of its mooring deployment program. On a 18O-Salinity diagram, the waters in Northeast Channel appear along a mixing line between end members representing a mixture of Labrador Shelf and St. Lawrence estuary water at one end and Slope Water at the other. The influence of Maine river input is indicated by a deviation from this line. In the central bank, the salinities were lower in 1996 relative to 1995, with Maine river influence evident in 1995 (and in data from earlier years), but not in 1996. The Scotian Shelf source water seemed similar in salinity in 1995 and 1996.
ADCP data (Charles Flagg and Julio Candela): Shipboard ADCP data have been collected on 37 cruises, from 1994-1996. All have been processed. Data from narrow band systems have been processed at Brookhaven, while that from broad band systems has been done at WHOI. The backscatter from the narrow band systems has been processed and work is continuing on the backscatter-to-zooplankton biomass relationship. This relationship is being developed using net data from the broad-scale surveys collected and processed by Ted Durbin. The data and cruise tracks are available on the BNL homepage. The URL is: http://www.oasdpo.bnl.gov/~oasdpo/mosaic/globec/.
Julio is working on a better scheme for de-tiding the velocity data. While available at WHOI, they are not ready for final release. De-tided views of the data will be developed and made available. Work is also progressing on putting the narrow band data into an NODC ADCP format to make it easily available.
Satellite data (Jim Bisagni): Satellite derived (AVHRR) SST data from late 1993 to the present is on line and available. Also, gridded, optimally-interpolated SST maps are available - having been developed for a Gulf of Maine Regional Marine Research Program.
An interesting feature observed during 1995 is a cyclonic eddy located in Northeast Channel. A manuscript with Peter Smith was presented at the recent ICES meeting. The eddy was clearly seen in satellite data during April, moving to its inward most location (toward the Gulf of Maine) on May 4, and then moving back outward until May 10, when the SST signature was lost. It was also observed in Peter Smith's Northeast Channel east mooring, first at 100 m depth and then a few days later at 23 m depth. It was obvious in the temperature, salinity and velocity data sets. [Ken Brink pointed out that the tilt in the vertical axis could be used to indicate growth or decay of the eddy]. To suggest what was causing the movement of the eddy, the barotropic forcing of Ramp et al., (1985) for Northeast Channel flow was considered. In a frequency dependent, multiple regression analysis, the along-channel current did appear to respond to the cross channel wind, consistent with a wind induced setup/set down of the Gulf, as proposed by Ramp et. al., (1985).
Potential energy maps have been developed from the broad-scale
hydrographic data. High stratification values associated with the
Scotian Shelf water influx during February 1995 on the northeast
peak of Georges Bank were comparable to the June values associated
with seasonal stratification resulting from vernal warming.
Long Term observations
Drifters (Dick Limeburner): Eighty-three drifters have been deployed in 1995 and 1996. Seventy-five were drogued at 10 m depth and 8 at 40 m. Movies of the drift tracks are on the GLOBEC web site. In 1995, deployments were in the central bank region, while in 1996 deployment sites in northern Great South Channel (NGSC) and Browns Bank (BB) were added. Source regions for the Bank appear to be in the Gulf of Maine and NGSC - and to a much lesser extent, Browns Bank. Estimates of the mean flow in boxed areas have been made. In the central part of the Bank, no meaningful wintertime mean flow existed.
In 1995 a major event in late January took 5 buoys off the southern flank of the Bank. After that, the buoys largely stayed in the central region less than 60 m depth for a number of months - but with little indication of a strong re-circulation around the Bank. In summer, a racetrack-like circulation developed around the Bank, with some escapement into the Gulf of Maine - although those buoys largely came back onto the Bank. The loss of buoys across the southern flank was generally associated with rings.
In August 1996, a hurricane passed over the Bank and a large displacement was observed for drifter buoys in NGSC and on Nantucket Shoals - but not for buoys on the Bank itself.
Looking at the broad-scale hydrography, locally near the tidal mixing front on the southern flank the cross-bank density gradient changed sign from on-bank in winter (denser water in the shallow, central part of the bank) to off-bank in summer.
Moored observations (Peter Smith): A series of moorings are monitoring the inflows to the Gulf of Maine system through Northeast Channel (NEC) and around Cape Sable - from 1993 to the present. Cruises are also making ADCP and hydrographic measurements across NEC and around the Browns Bank-Cape Sable region. One mooring is located off Cape Sable and two mooring are in NEC - on the east and west sides of the channel (NEC-E and NEC-W). NEC-W was moved onto the northeast peak of Georges Bank from June 1994 to June 1995, to support the stratification experiment.
In the hydrography, in October 1993, an episode of high salinity (>35.5 PSU) and temperature (>15o C) in NEC deep waters (>100 m) was associated with a ring offshore.
Repeated ADCP sections were made across NEC to develop a de-tided velocity section showing the inflow on the east side and outflow on the west side. Net transports into the Gulf are consistent with earlier measurements (Ramp et al., 1985).
The focus of analysis is:
Long term moorings 1 (Jim Irish): The passage of hurricane Edouard on Sept 3, 1996 over the southern flank mooring caused a strong current response (order of 2 knots) with a baroclinic structure that was observed off-bank.
One should consider occurrence of internal waves-solitons on the southern flank as a possible retention mechanism. During year 2, the southern flank mooring had SEACATs at 20 and 30 m depth, sampling at 2 minute intervals. Large solitons seen in the temperature and density records during high stratified times were timed with the switch in the tidal current to the on-bank direction.
Long Term Moorings 2 (Bill Williams): Four 6-month
deployments have been completed in the long term mooring program and
the fifth period has been started. Observations have been acquired
from October 1994 to October 1996. Three sites have been
instrumented - the crest of the Bank (Oct 1994 - Sept 1995), the
Northeast Peak (in the first year by BIO, but since then by this
program) and the southern flank. On the southern flank,
meteorological (MET) measurements have been made, although some
parameters are missing for the first year of observations. Air
temperature and PAR have been made at each site on each deployment.
A full suite of MET measurements were made on the stratification
mooring ST1 in year 1.
Process mooring measurements 1 (Bob Beardsley): Surface MET data at the ST1 site have been used to estimate the surface heat flux (Qn) and wind stress. Initially Qn was negative during February and then became positive during the spring and summer.
The vertical thermal stratification appears to begin after the major Slope Water influx event in May 1995. The stability associated with the influx could have trapped the surface heating in a near surface layer, and thus triggered the subsequent development of stratification. The records show the influx of Scotian Shelf water in March and Slope Water in both May and August.
Process mooring measurements 2 (Steve Lentz): A depth-averaged temperature time series was calculated at the ST1 site and compared to the integral of surface heat flux Qn. The two curves agree on the seasonal time scale, suggesting that, to lowest order, a one-dimensional heat balance exists along the southern flank. More work is needed to check this initial description.
Retrospective heat flux calculations (Jim Bisagni): An equilibrium temperature heat flux method is being used to develop a historical surface heat flux time series for the Bank. Using model wind data from Fleet Numerical Oceanographic Center, shortwave data from Dick Payne at WHOI, dew point temperature climatology and satellite-derived SST, a computed heat flux series was used to compare with the measurements from ST1. The comparison is moderately good, and suggests that the method can be used to develop a historical heat-flux series for retrospective analysis of stratification development on Georges Bank.
BASS experiments (Sandra Werner - presented by Bob Beardsley):The BASS tripods were deployed twice at the ST1 site in 1995 - once when the water column was well mixed and once when well-stratified. Analysis will focus on the importance of stratification on the vertical flow structure and on bottom stress on a tidal time scale, and on developing a subinertial momentum balance.
Ring effects on the Bank (Jim Churchill): The response of Georges Bank currents and larvae to the passage of rings was examined. Three rings were considered during 1995. Ring A, in March-April, did not seem to influence the Bank. Ring B, in May, had a major effect, with the along-bank current switching from eastward to westward in advance of the approaching ring (that the currents were eastward was contrary to expectations of the mean flow - and both the ring and winds may have played a role in the occurrence of eastward flow). A surface buoy went westward at about 50 cm/sec in what appeared to be a frontal jet. In the moored data at ST1 the influence of Ring B was most evident at depth. The cross-bank residual current at ST1 can account for the progression of the Slope Water intrusion toward site ST2. Ring C passed by in August. Its influence was observed mostly in the near surface layer.
Visualizing model runs and observations (Jim Manning): a variety of visualizations of data were shown illustrating the use of different tools (e.g., AVS and MATLAB) to compare model runs and observations.
Micro-structure (Russ Burgett with Dave Hebert and Neil Oakey): The objectives of the micro-structure measurements are: to determine the processes and dynamics responsible for the vertical structure of the mixing rates; to determine the bottom stress at each location and a parameterization to explain the variability of the stress; and to determine the relationship between the biological patchiness and turbulent mixing rates. Measurements were made on two cruises - at two sites on each cruise, a shallow and a deep location. The first cruise was in late April-early May, when the water column was well mixed. The second cruise was in June when the water column was stratified. Micro-structure measurements were made using the EPSONDE profiler. ADCP and CTD measurements were also made. On the June cruise, Lew Incze made plankton pump measurements and Mark Berman and Jack Green made acoustic measurements with a TAPS system.
The dissipation time-series profile shows high values near the
bottom and an obvious tidal signal. The velocity cycle leads the
dissipation signal, with the lag increasing with distance above the
bottom to maximum lags of over 3 hours. Bottom stress calculations
are being done.
PO Inter-annual Variability Working Group
afternoon, November 6.
David Mountain (Rapporteur)
The inter-annual variability evident in the broad-scale hydrographic data was discussed. The two major features identified were that the salinities observed in 1996 were about half a salinity unit lower than observed in 1995, and that the oxygen isotope analysis indicated no coastal Gulf of Maine contribution to the central-bank waters in 1996 (while the 1995 and earlier MARMAP data regularly showed a coastal Gulf of Maine contribution). At least two questions arise - what caused the change in salinity (a source water issue?) and why was there no Maine coastal contribution in 1996 (a circulation issue?)?
A number of steps were identified to investigate these questions:
As a separate item, the desirability of using the hydrographic data from the program to develop a climatology for the Bank was discussed. This analysis would be similar to the work of Charlie Flagg in the Georges Bank book, but it would be for the GLOBEC observational period. Regions of the Bank were identified, based on the broad-scale station grid, and the seasonal change in water properties in these regions will be determined. David Mountain will develop the seasonal temperature and salinity climatology for the Bank during the GLOBEC field years, while Peter Smith will compute the historical climatology from the AFAP data base using the same subdivisions of the Bank for reference. Bob Houghton will attempt to characterize the oxygen isotope versus salinity relationships for the same subdivisions from the GLOBEC and MARMAP data.
A review of hydrographic data from the NMFS spring and fall
trawl surveys showed that the decrease in salinity noted on the Bank
between the spring of 1995 and 1996 was evident in the Gulf of Maine
as early as the previous fall (the fall of 1994 had higher
salinities in the Jordan Basin region than did the fall of 1995).
PO Slope Water Intrusions Working Group
afternoon, November 6.
Jim Irish (Rapporteur)
The group started out looking at the moored time series from the Stratification experiment which included the main Stratification Mooring (ST1) and the Long-Term Southern Flank Mooring in 1995. Jim Churchill had identified a few warm-salty events in the main Stratification Mooring data and related them to satellite images of warm-core rings. Jim Irish pointed out the same signals in the long-term moored data which existed before and after the main stratification mooring and included the fall of 1994. Based on plots from these two moorings, a number of significant warm-salty events were identified which appeared related to the presence of warm-core rings offshore. A ring was also identified which did not have any accompanying signature at the moorings. A number of satellite images and CTD sections were also studied to help interpret these events. Jim Manning and Dave Mountain pointed out a May 1994 ALBATROSS cruise which also appeared to document warm-core ring effects on the south flank of Georges Bank. This is interesting because we thought that the historical data did not show the effects of the warm water extending as far on the Bank as observed.
Besides the warm-salty events in the fall and summer, during the winter of 1995 several cold-fresh intrusions were observed in the moored observations which were attributed to Scotian Shelf water. Jim Bisagni's satellite images (between cloudy periods) also showed this cold water coming across the Northeast Channel.
Based on the identified warm-core ring and Scotian Shelf water events, a compilation was produced (Figure 1) which summarizes:
The results were further discussed, summarized, and presented in
the late Friday afternoon physical oceanographic lecture.
PO Stratification Working Group
Ken Brink (Rapporteur)
The subgroup on Stratification, Mixing and Wind Driving met to discuss analysis plans and to arrange for cooperation and data sharing. The main topics discussed included:
Dave Greenberg described some results from a finite element model of the time dependence within the Gulf of Maine (GOM), Georges Bank and Scotian shelf. The model used a truncated Bay of Fundy with tidal boundary conditions to mimic the overall GOM tidal response. Results showed that the wind response reached near steady conditions after three to four days so that a steady model would be useful for many studies of the Bank. The along-shore wind stress produced an Ekman response over Georges Bank and Scotian shelf with a compensatory inflow through the NE Channel. Upwelling was evident within the Gulf and around the Bank wherever there was substantial topographic variation.
Changsheng Chen described a two-dimensional cross-bank model with which he investigated the separate effects of surface buoyancy flux and tidal and/or wind generated mixing. Heating alone from a winter-time initial condition led to a slight increase in anticyclonic flow around the Bank while cooling during the subsequent fall/winter decreased the anticyclonic flow and actually reversed the flow on the southern flank. Surface heating with tidally generated mixing resulted in a greater increase in anticyclonic flow during the summer than heating alone. After cooling reduced the anticyclonic flow during the fall/winter, the second heating cycle produced intensified anticyclonic jets along both the north and south flanks. There was a discussion about whether the density gradients between the crest and southern flank matched those shown by Dick Limeburner.
Frank Bub demonstrated some results from his 12 regions by four depth bin box model for the Gulf of Maine/Georges Bank system. Adjustable variables used to match observed temperature/salinity distributions were transports and the vertical and horizontal turbulent exchanges between the boxes. The model was forced with inflow from the Scotian shelf and required to match mean conditions for each box derived from the AFAP data base. The model showed a cross NE Channel flow reminiscent of observations. Discussion centered on the lack of a deep Slope Water inflow through the Channel. It was suggested that the necessary inflow was supplied from upper slope boxes on either side of the Channel.
Wendell Brown described an analysis of coastal sea level and bottom pressure records within the Gulf of Maine showing a vigorous response due to wind with 8 to 13 day periods. Maximum sea level response was due to nearly alongshore winds from the east or west. The maximum pressure difference response, proportional to geostrophic transports, occurred at 3 to 4 day periods. Based upon the results from Greenberg's frequency response results for the GOM, comparisons were then made to daily steady-state model results driven by "Halifax" sea level and 36-hour-averaged winds. Although there was general agreement, the steady-state model under estimated the sea level response for strong events.
The last presentation was by Chris Naimie in which he indicated
that 4D results from the Dartmouth Finite Element Model, based upon
climatological forcing were archived and available to
observationalists for comparison with their data. Comparisons with
moored data will be available on the Dartmouth WWW site. Chris then
described the modeled asymmetrical response to tidal forcing on the
northeastern flank of the Bank. Due to the bottom slope and density
stratification, onshore near bottom flow produced increased
stability over the upper flank while down-slope flow resulted in
reduced stability and increased mixing. Discussion centered on how
the model dealt with turbulence. It was noted that the hydrostatic
condition and turbulence closure assumptions precluded the model's
ability to explicitly include high frequency phenomena such as
tidally generated solitons and the localized turbulent mixing that
PO Modeling II Group
Thursday afternoon, November 7.
Peter Smith (Chairman) Bob Houghton (Rapporteur)
The session began with a discussion of whether or to what extent model calculations of features such as Lagrangian drifter tracks compare with observations. The success is mixed. The model is a representative of climatology and not the response to forcing of a particular year. There was discussion of the model response and robustness to stochastic forcing of extreme events such as storms or Gulf Stream rings. Chris Naimie, Charles Hannah, and Dick Limeburner were going to pursue the issue of whether model runs could be useful in designing drifter deployments in Phase II.
Dan Lynch described plans to run hind-casts of the response to observed 1995 and 1996 forcing. The domain would be confined to the Georges Bank region covered by the broad-scale sampling (~150 m isobath) and boundary conditions would convey all information of the far-field forces and water properties. These boundary conditions will be generated in part by matching the observed velocity field.
Model calculations will be used to identify the role of Gulf Stream rings in generating the Slope Water intrusions. Except for some of the process study sections, little is known of the offshore fields advected onto the outer Bank. The May 1995 intrusion was best studied, especially by biologists, and should be examined first.
A description of the inter-annual variation is not yet fully defined, but it is hoped that the hind-cast calculation will shed some light on 1995 and 1996 differences.
For the stratification, it is thought necessary to first
describe the field data and get the forcing right, and then
hind-cast. An important question concerns the connection between
vernal stratification and Slope Water intrusions "do they affect the
precondition?" Model runs with and without heat and tides would be
The Drifter Group
Friday afternoon, November 8.
Dick Limeburner (Chairman) Charles Hannah (Rapporteur)
The drifter group examined the GLOBEC drifter trajectories and simulated drifter patterns (from the climatological seasonal mean fields). The emphasis was on developing descriptions of the flow patterns and understanding the utility of the seasonal mean flow.
We explored the idea that the seasonal cycle can be described by the transition between two states.
Further work is planned to provide a quantitative examination of 1) the seasonal spin-up and spin-down of the re-circulation time scale; and 2) the seasonal cycle in near surface velocity at key locations around the Bank. A publication is planned.
Dick Limeburner led a lively discussion of the placement of the
drifters during 1997 which will focus on the pathways from the Gulf
of Maine to Georges Bank. The tentative deployment plan is shown in
Figure 2: 'Satellite tracked drifter deployment
sites for the 1997 cruises.'. The top panel shows where
drifters would be deployed in January and February, the lower panel
for the rest of the spring and summer.
Summaries of Friday afternoon mini-lectures, Glenn Flierl (Rapporteur)
Decadal-scale Variability (Charles Hannah): From historical hydrographic data, the 1958-1968 period was 1o to 2o C colder while the 1972-1987 period was 1-2o C warmer than average. The bottom temperatures show similar changes, though the magnitude was about 1o C with a maximum of 4o C along the shelf break. During the cold years, the geostrophic transport was about 2 Sv higher relative to 1000 m. The circulation on the Bank did not change strongly.
Seasonal Variability (Bob Houghton): The 18O/S relationship is much tighter than the T/S relationship and can be used to distinguish water masses and the fractions of these in a particular sample. On the broad scale, one can identify Labrador Shelf Water, St. Lawrence River Estuary Water, Scotian Shelf Water, and Labrador Sea Water. The NE channel had a mixture of Labrador Shelf and St. Lawrence waters. Salinity on the Bank showed 0.8 PSU variation with 1996 being 0.3 to 0.5 PSU fresher. This variation occurred over the full depth of the Gulf of Maine. In 1995, Georges Bank was not on the mixing curve, implying about a 20% contribution from GOM coastal waters. In 1996, there was no GOM coastal water in the Bank samples. Perhaps the spring fresh water was too light to get onto the Bank. There were significant changes in the properties of the source waters.
Stratification (Bob Beardsley): Observations of the stratification on the southern flank showed that it was reduced by mid-November, presumably from cooling and storm-induced mixing. A Slope Water intrusion was seen in early November and a Scotian Shelf intrusion in mid-December. The surface waters warmed by mid-March. Scotian Shelf and Slope Water intrusions were seen in May.
Intrusions (Jim Irish): The Slope Water intrusions were characteristically warm and salty, while the Scotian Shelf water was cool and fresh. Seven events were observed during the period May 1994 to September 1995. The changes in salinity and temperature were as big as the annual signal. A streamer from the Scotian Shelf could be seen by satellite during one intrusion. The signal was detected at various depths and often looked like a sloping front advecting across the mooring. During May, there was onshore to offshore movement.
Drifters (Dick Limeburner): In 1995, drifters were seeded at 5 sites; in 1996, various other source sites were used with some floats being placed on Browns Bank. The floats were drogued at 10 m, but did move relative to the water and diverged from true fluid trajectories over a few days. January-October 1996: at the end of January, 5 tracks left the Bank via a Ring. July-October: an organized circulation pattern was visible. Most of the water drawn off the Bank went out to Rings. In 1996, there was an anticyclone in the Great South Channel entrance. Wind events were visible and affected the flow most strongly within the 60 m isobath. The mean flows were weak over the winter; circulation developed on the north flank in July. During July and August, there was reverse flow on the NW side. After July, there was northward flow in the Great South Channel (which also appeared in the model calculations). During the 1996 winter, there was SE drift. It appeared as though the strong jets were unstable and ejected eddies which may have caused significant mixing from the GOM. Again, drifters crossed the shelf-break due to Rings.
Data Assimilation (Dan Lynch): The Dartmouth team will
be producing detailed 3-D circulation maps for individual cruises,
including both broad-scale and process cruises. Early attention
will be on 1995. These will be in the form of a hind-cast of the
physical environment, obtained by assimilating moored, CTD and ADCP
field data. The geographic scope of the hind-cast will be
approximately the same as the broad-scale survey, i.e. it will
cover the bank per se, roughly shoalward of the 150 m isobath.
Resolution will be approximately 1 km horizontally. Each hind-cast
will have estimates of error and will be archived along with the
cruise data. Because the assimilative model is tide-resolving,
there is no need to de-tide the ADCP data prior to its assimilation.
Drifter trajectories will not be assimilated; they will be used as a
check on the Lagrangian impact of the computed error/uncertainty
Vital Rates/Population Distribution and Dynamics Group
Wednesday and Thursday mornings, November 6 & 7. Ted Durbin & Dian Gifford (Chairmen), Charlie Miller (Rapporteur).
It was decided to have each investigator characterize information available or developing on the target species for which they are responsible. Notes on those talks are ordered here by group. The discussions overall gave a sense of steady progress with investigations of both fish and copepod target species.
Broad-scale Survey: Abundance and Otolith Analysis: For the 1994 process cruises, single broad-scale cruise and COP cruises, larval fish were sorted initially at sea. More intensive resorting of the process cruise samples has been completed in the laboratory at NMFS (G. Lough). No additional sorting of the broad-scale or COP samples is currently planned. Jack Green reported that sorting of the 1995 broad-scale larval samples is underway at the Sorting Center in Szczecin, Poland. Data for the May 1995 cruise are due from the Center in December. All 1995 samples will be completed under the current agreement. High priority has been assigned to March, April, and May, with second priority to February, June, and July. No funding as yet been provided for analysis of 1996 samples, although some 1996 bongo tows have been included in the work contracted for 1995 materials. A "sort" at the center includes removing all fish larvae, identifying them and both measuring and storing cod and haddock larvae in vials of ethanol. Vials will be returned to J. Green for analysis of birth date by otolith ring counting. It is not anticipated to study otolith ring widths to estimate growth rates as a function of time. The location and responsibility for larval fish studies in the GLOBEC Georges Bank Program will be changing soon. Sandy Hook Laboratory will be phasing out of the cod-haddock work after working up the 1996 data, and all of the GLOBEC work will transfer to the Narragansett NMFS facility for the 1997 sampling and beyond. Funding for sorting the 1997 and 1998 broad-scale samples is in the budget approved by the program.
Physiological Condition and Growth: Elaine Caldarone demonstrated a strong, positive correlation from experimental data between the ratio RNA/DNA and the rate of increase of protein (growth) in larval cod. Most of the field estimates of RNA/DNA for larval cod and haddock are complete through 1995. Years studied to date can be rated as follows:
Fish from station 17 of the April 1995 broad-scale cruise were in very poor condition compared to fish sampled from the rest of the Bank.
Larval Fish Ecology: A full picture of studies of larval fish ecology carried out during Process Cruises was not available to us because Greg Lough was not able to attend the workshop.
Cod Larval Feeding Studies: Elaborate experiments on feeding by early stage cod larvae were reported by Scott Gallager. Larvae newly hatched from laboratory-maintained cod are taken to sea and allowed to feed on natural foods. The foods (protozoa) are size fractionated, labeled according to size with fluorescent dyes varying in emitted color and recombined. Larvae are allowed to feed, then collected. Gut content analysis by epifluorescent microscopy shows which sizes of food are consumed. Very early larvae eat protozoa as soon as the mouth is open and up to at least 7 days of age, well before yolk sac absorption is complete. Crustacean nauplii are not eaten in this interval. Upcoming studies in S. Gallager's laboratory focus on the role of the light field in visual spotting of prey by larval cod. It is already clear that most prey are taken from below. In tanks they are silhouetted against the apparent darkness outside Snell's window. How this operates in the field with a chaotically oscillating water surface will require modeling work.
Broad-scale Survey Studies of Target Species Abundance: Ted Durbin showed stage proportions for Calanus finmarchicus from selected stations from all cruises of the 1995 broad-scale series. Different stations seemed to start accumulating a stock of younger Calanus stages at different times ranging from January through March. Most stations showed two generations, one with prolonged egg input and slow development before May, the other after. There was sharp hiatus in both naupliar and copepodite abundance during May at all Bank and Gulf of Maine locations. Station 38 in the southwestern outlet of the Gulf of Maine showed a strong February to April generation, but no early stages after May. This one generation pattern was restricted to that region. T. Durbin reported that the planktoneers have counted 1-m2 MOCNESS samples from all priority 1 stations from the 1995 broad-scale cruises and from priority 1 and 2 stations for 1996. Data books are available for 1995. A process of conversion to a database format is underway. T. Durbin presented a series of questions that he intends to investigate using the data now available.
Recruitment Rates of Calanus finmarchicus: In addition to work by the URI plankton group, Jeff Runge has counted adult females of all species from all of the 1995 broad-scale samples. He showed maps developed from those data by "kriging", a two-dimensional method of data smoothing and contouring. From each station 30-50 female C. finmarchicus were also rated with an index of reproductive condition (scale of 1=unripe to 7=ready to spawn shortly). Using a correlation (r) between the index and actual egg production developed experimentally on process cruises (r2 = 0.7), the total expected egg production at a station can be predicted from the product of expected individual fecundity and estimated female abundance. Kriged maps of this variable across the Bank were mostly similar to the abundance maps, since most females had high indices at all places and times. Strong concentration of early spawning output occurred at Gulf of Maine stations and over the northeast peak. May productivity was less than that of earlier months, but still high enough to make the May hiatus in abundance of all naupliar stages surprising. By May, the near absence of females over the shoaler areas of Georges Bank made a large blank hole in the spawning output map for Calanus.
Calanus finmarchicus Growth Rates: Bob Campbell of the URI group showed molting and growth rates for copepodite stages of C. finmarchicus estimated from experiments on Process Cruises of 1994 and 1995. Animals were sorted by stage and a sub-sample weighed. They were held in natural seawater for a period, then staged and weighed again to determine molting rates and weight gain. Most values in a very broad scatter of results were positive with a vague central tendency around 0.1 d-1, which is a fairly dramatic number (biomass doubling times of only one week). A laboratory experiment at full nutrition was carried out during summer 1996 with which to compare these results. Stage-wise development time data from these experiments are of a new standard, showing progressively longer intervals in each stage and cleanly equi-proportional change in stage durations at different temperatures. These data will be found indispensable by the modeling group. Similar data developed by EU-TASC at the Bergen mesocosm facility will provide a good comparison for stocks from the eastern side of the range.
Calanus finmarchicus Development: Charlie Miller reported two studies on C. finmarchicus development in the field.
Calanus finmarchicus Feeding: Feeding experiments with field-collected C. finmarchicus in late stages were described by Dian Gifford. She stated that as the copepod development season progresses the copepods are more and more dependent upon heterotrophic protozoa as food. She found that April cruises show very low levels of food abundance in the 5 to 20 m range most favored by Calanus as a diet. This may match Miller's observation of an apparent hiatus in developmental progress sometime in early April 1996. D. Gifford noted that at times, the pelagic protozoan community is dominated by Mesodinium, believed to be a "mixotroph". Mesodinium is an ideal size to serve as copepod food, but it has astounding capability for making escape jumps which apparently protects it from predation.
Genetic Studies of Target Copepod Species: Genetic studies by Ann Bucklin have shown relatively low levels of genetic variation of a mitochondrial gene (16S) in C. finmarchicus, compared to levels found in Acartia for the same gene and Meganyctiphanes for two other mitochondrial genes, Co1 and Cytochrome B. She can differentiate west Atlantic from east Atlantic stocks of Calanus, but the predominant genotype was the same in all regions, and no distinctions were consistently found within regions. She is currently examining other population genetic characters for Calanus, intending to check conclusions based on mitochondrial genes. Planned efforts at Norwich in the UK will allow a trans-Atlantic comparison. A. Bucklin also reported that a PCR-based species identification system has been developed for Pseudocalanus species common on and around Georges Bank. This will be applied to determine the relative importance of P. moultoni and P. newmani at different times and places in the region.
Zooplankton and Particle Distrbutions from the VPR: Cabell Davis and Carin Ashjian reported that 10 Video Plankton Recorder transects have been fully analyzed from GLOBEC studies over Georges Bank. Horizontal and vertical zonation of abundant zooplankton (and in some cases phytoplankton) species are very well characterized in these data, at least for adult stages that are readily recognized. Some species are well characterized at several late development stages. C. Davis and C. Ashjian showed some of the data, which are too complex to characterize simply here. An enormous increase in data production rates is expected early next year when new hardware and software for image analysis come on line. This system recognizes actual species categories in images with about 95% accuracy. The system is slow compared to human operators, but it works tirelessly.
Small-scale Vertical Distribution of Zooplankton: Lew
Incze reported the availability of pump profiles at 1 meter
resolution from the sea surface to 50 meters at 16 stations
collected in May 1995 in conjunction with Micro-structure studies by
Dave Hebert and Neil Oakey. He hopes to begin counting of these
Predation Group Sessions
Wednesday and Thursday, November 6-7.
Larry Madin (Chairman), Erich Horgan (Rapporteur)
Data Status: Initial discussions began with review of data from the 1994 and 1995 field seasons and the status of sample analysis. Both hydrographic and zooplankton data (1-m2 MOCNESS and 10-m2 MOCNESS) are now available for all process cruises in 1994 (AL9403) and 1995 (SJ9503, SJ9505, SJ9507, EN268):
Formatting of MOCNESS data was discussed; the GSO and WHOI groups plan to coordinate with the Durbin Process Group to choose a similar format for entry of the data into the GLOBEC Data management system. Existing search and graphics tools in the GLOBEC database will probably be used for retrieval and analysis. It was agreed to generate a list of the remaining unanalyzed 1-m2 MOCNESS and 10-m2 MOCNESS hauls to understand where holes in field collections and disposition of the samples occur. Scarce support for additional sorting makes it important to prioritize remaining samples.
Predator Feeding Rates: Feeding rate data for the major predators that have been investigated so far were discussed. This is summarized below. If all stages of the target prey species (eggs through adult for copepods, all sizes of larval fish) are considered, then there are potentially more predators than have previously been considered, including omnivorous copepods and sand lance. Immunoprobes were suggested as a means to screen a large diversity of other possible predators for the presence of Calanus or Pseudocalanus. Immunological screening for Calanus is planned to begin in January 1997. Sand lance are difficult to sample, but Bill Michaels offered specimens from his collections for preliminary analysis, and there are feeding data for sand lance in the literature.
There was further discussion of immunological and molecular probes for detection of prey species. The immunoprobe for Calanus seems to be working well in preliminary tests, and Madin/Bollens have funding to support development of a similar polyclonal probe for Pseudocalanus spp. On Friday, Madin and Horgan visited the Bucklin and Kocher labs at UNH to discuss application of DNA probes for identification of target species in predator stomachs. Cod and haddock specific probes have been developed by Rosel and Kocher with COP funding, and these probes could presumably be available to the Predation Group for detection of larval fish as prey of invertebrate predators. Specific DNA probes for copepods developed by Ann Bucklin may be valuable for detection of the copepod target species. We plan to work with these groups to try the probes in comparison with the polyclonal methods already under development.
Summary of feeding data:
Provisional Estimates of Predation Mortality: After reviewing data on abundance and feeding rates of major predators, one cruise (May 1995, SJ9507) was picked and estimated predation intensity at the Crest and Flank sites was compared (Table 1). In this exercise, abundance data were used from process cruise tows and also from broad-scale tows (using 1-m2 MOCNESS data from Durbin group) along with the best estimates of feeding rates to calculate a range of predation effects on the prey groups. These are summarized in Table 1. This is the approach that will be used generally in combining rate data with distribution maps of prey and predator from broad-scale results. Predation rate functions need to be further refined to take temperature and prey abundance into account for the major predator species.
The preliminary exercise assumed a mixed water column, but there are plans to make future calculations with depth-stratified data. The estimated predation impacts were far greater at the Crest site (range: 2% to 112% prey stocks d-1) than at the Flank site (range: 0.07% to 6.5% prey stocks d-1). In both cases, predation impact was largely a function of predator abundance, measures of which are often highly variable between adjacent collections.
This method of estimating predation effects, and the sample results were discussed with representatives of the modeling groups (D. Lynch, C. Naimie, C. Davis, D. McGillicuddy, et al.) on Friday afternoon. A goal agreed upon by the predation group and modelers is to produce depth-stratified maps of predator-prey co-occurrence which can be used to estimate predation mortality for each prey category, depending on the predation rate functions which connect predator-prey pairings. Model development will then proceed to incorporate information from day and night differences in predator-prey distribution, which will begin to address the behavioral component of predation.
Barbara Sullivan and Carol Meise have already analyzed previous MARMAP data on predator abundance on the Bank, and these data (in forthcoming DSR volume) were recommended for use as an initial data set by the modelers.
|CREST Site MAY 1995|
|hydroids||copepod eggs ? *||678||3.6 ml h -1||6%|
|hydroids||copepod eggs ?||13,000||3.6 ml h -1||112%|
|hydroids||1000 nauplii||678||1.9 ml h -1||32||3%|
|hydroids||1000 nauplii||13,000||1.9 ml h -1||624||62%|
|chaetognaths||1875 copepods||44||3 copepods d-1||132||7%|
|chaetognaths||1875 copepods||165||3 copepods d-1||495||26%|
||1875 copepods||4||10 copepods d-1||40||2%|
||1875 copepods||30||10 copepods d-1||300||16%|
|"shrimp"||1875 copepods||4||10 copepods d-1||40||2%|
|"shrimp"||1875 copepods||0.06||700 copepods d-1||42||2%|
|1875 copepods||0.6||701 copepods d-1||420||22%|
|SOUTHERN FLANK Site MAY 1995|
|hydroids||copepod eggs ?||15||3.6 ml h-1||0.10%|
|hydroids||copepod eggs ?||74||3.6 ml h-1||0.60%|
|hydroids||copepod eggs ?||450||3.6 ml h-1||4%|
|hydroids||9100 nauplii||15||1.9 ml h-1||6||0.07%|
|hydroids||9100 nauplii||74||1.9 ml h-1||32||0.30%|
|hydroids||9100 nauplii||450||1.9 ml h-1||180||2%|
|chaetognaths||4000 copepods||33||3 copepods d-1||100||2.50%|
|chaetognaths||4000 copepods||60||3 copepods d-1||180||4.50%|
||4000 copepods||0.5||10 copepods d-1||5||0.10%|
||4000 copepods||7.2||10 copepods d-1||72||1.80%|
|"shrimp"||4000 copepods||8||10 copepods d-1||80||2%|
|"shrimp"||4000 copepods||26||10 copepods d-1||260||6.50%|
|* egg abundance data unavailable at time of Workshop|
Cisco Werner began the discussion by describing the historical development and general capabilities of his individual-based trophodynamics model. The trophodynamics component simulates certain aspects of the early life history of larval fish on Georges Bank within the diagnostic seasonal circulation fields from the finite element model developed by Lynch and colleagues at Dartmouth College. The model traces the effects of feeding on growth of larvae and predicts survival based on individuals exceeding a certain age-dependent critical weight ("death barrier"). The prey fields for the larvae are frozen in time and compartmentalized in space with vertically uniform densities. The salient results of the model are:
Problems identified with the present version of the model include the fact that the actual prey distributions are not observed to be uniform, but rather aggregated at particular depths; some prey types are missing (e.g., microzooplankton); and that the effect of predators on the larvae needs to be included. Vertical migration of the larvae should be refined and some aspects of the foraging behavior and nutritional benefits of the prey species may be in error. During the discussion of the models a summary illustration of factors influencing the growth and abundance of larval cod on Georges Bank was created (Figure 3,).
To assess the predation question, it was suggested that a simpler "holistic" model could provide a complementary view of the problem in relation to the more mechanistic treatment of feeding in the trophodynamics model (Figure 4). The simpler model would treat larval growth rate as a known (exogenous) variable based on RNA/DNA field observations, and include several modes of mortality, including starvation, predation and advective losses. The larvae in this model would be allowed to migrate vertically and both predation mortality and growth rate fields could be treated in either a Lagrangian (drifting) or Eulerian (fixed) manner, with an additional stochastic component.
The session concluded with a wide ranging discussion of the details of the foraging behavior of larval fish. These aspects included:
A number of scientists involved in the collection of data during the 1994 and 1995 broad-scale surveys (i.e. AL9404 ( 31 May - 10 June 1994), EN259(10-20 Feb 1995), EN263(13-24 Mar 1995), EN265(11-23 Apr 1995), AL9505(9-18 May 1995), AL9506(5-15 Jun 1995), AL9508(10-21 Jul 1995)) are interested in creating synoptic distributions of cruise data. Of concern in this regard are processes which effect the distributions at temporal scales equal to or shorter than the duration of a particular broad-scale cruise (typically of order 10 days, as listed above).
The "synoptic correction" could best be conducted using a hindcast of the coupled physical/biological system for each individual broad-scale cruise. Given that such simulations are not feasible at the present time, subsequent discussion centered on the value of performing "advective synoptic corrections" using the vertically averaged circulation from numerical simulations of the climatological bimonthly circulation recently conducted at Dartmouth College. The group generally agreed that comparison between distributions of data at actual observation positions and at synoptically corrected positions could provide additional insight under some circumstances. This optimism was based mainly on:
Finally, general agreement was reached on the following points:
Status of Calanus model simulations: Dan Lynch summarized the status of the model simulations for Calanus finmarchicus, focusing on 2-D climatological results. The current template upon which GLOBEC zooplankton models are run uses a ten year average of MARMAP abundance data for Calanus finmarchicus with bimonthly average flow fields with non-replenished, passive partitions. These copepod abundances are averaged over depth (# m-2). The notion of depth dependency on distribution of copepods, as well as their predators, became one focus of discussion. Copepod depth distribution data for 1994 and 1995 broad-scale cruises (Ted Durbin's Group) has gone to Lynch. The depth distribution of Calanus in Wilkinson's and George's Basins are very important to efforts to incorporate sources of copepods to the Bank. Work already published by M. Mullin (thesis, 1963) describes Calanus in Maine Intermediate Water. Published submarine observations of Calanus in Wilkinson's and George's Basins will help understand abundances better than the net hauls done in the area because of the limitations in fishing the bottom boundary layer. The discussion considered comparisons to the MARMAP data (provided by Carol Meise) and the following points were raised:
The differences in vertical structure in the Gulf of Maine and on Georges Bank were highlighted. For example, the GOM deep basins are known to show a high degree of vertical structure with later copepodite stages concentrated in the bottom 25 meters. Thus, sampling that did not include the bottom layers may be in error. On Georges Bank, the distributions (by comparison to those in the GOM) are more homogeneous in the vertical.
There was a suggestion to write a paper (in the near short-term) on the vertical structure of the zooplankton species (Calanus) on the Bank based on the '95 broad-scale surveys. This paper would/should precede the 3D model solutions that would be "coming on line" next year.
Extensions to Calanus model solutions: Wendy Gentleman discussed extensions to the (Calanus finmarchicus) solutions presented by Dan Lynch, by including spatially-dependent mortality and growth. For example, with mortality prescribed as a function of water column depth (higher mortality in shallow waters), the results show greater survivorship over Georges Basin. Similar model sensitivities were observed with spatially dependent growth rates. Both of these results show the types of sensitivity studies that could be accomplished with the present model formulation.
It was suggested that a good starting point/simplifying assumption for the model formulation may be to assume uniform growth (development) rates, with dependence only on temperature. With regard to food limitation and effects on growth/development, it was also pointed out that:
Jeff Runge described the need to include some measure of "condition" with copepods being advected in the models. Craig Lewis thought an advectable Eulerian indicator of health, or condition, may be used, similar to Droop's equations (1973). Other information the modelers needed includes data for the duration of the stages (generation times) for Calanus, and the seasonal, broad-scale distribution of predators and size class(es) they prey on.
SUMMARY for Calanus finmarchicus modeling strategy:
Preliminary results in modeling Pseudocalanus: Dennis McGillicuddy summarized preliminary results in modeling Pseudocalanus in the Georges Bank - Gulf of Maine Region. The underlying scientific objective here was to determine the mechanisms that control variations in the seasonal abundance patterns of Pseudocalanus. The observed distributions were hypothesized to result from the interaction of the population dynamics with the physical circulation.
Observed Distributions: Pseudocalanus distributions provided by Carol Meise were objectively analyzed using the OAX software package provided by Charles Hannah, et al, from BIO. The objective analysis was performed in the MARMAP1 domain (this area includes the GOM, the southern tip of the Scotian Shelf, Georges Bank, the shelf region south of New England, and portions of the Slope Water) on the log-transformed vertically integrated mean abundance of the total population (including all stages). Error statistics of the input data were assumed to be spatially and temporally uniform. In January-February, Pseudocalanus is concentrated near the coast, with the bulk of the population residing inside the 60 m isobath. A very weak local maximum occurs on the crest of Georges Bank. By March-April, the coastal population has increased somewhat; appreciable concentrations extend offshore just beyond the 100 m isobath. A substantial increase in the population is evident on Georges Bank, with highest concentrations inside the 60 m isobath.
Experiment 1 (Advection and Diffusion): A single passive tracer is initialized with the observed January-February distribution and run forward for 60 days. The January-February Lagrangian residual flow field is specified. The results show that the coastal population and the local maximum on the crest of the Bank dissipate as they are diffused away from their places of origin. The tongue extending from the eastern shore of Cape Cod into the Great South Channel is advected to the southwest.
Experiment 2 (Advection, Diffusion and Growth): In this simulation, simple population dynamics are added in the form of exponential growth with a doubling time of approximately 40 days. The results show that the growing coastal population diffuses outward into the interior of the Gulf of Maine. A tongue of high concentration protrudes southward across the 100 m isobath in the vicinity of the Maine Coastal Current. Growth of the Georges Bank population is not quite able to keep pace with advective loss out through the Great South Channel. There is a small but discernible flow of Pseudocalanus onto the Bank just south of the 100 m isobath label in the northern part of the Great South Channel.
Experiment 3 (Diffusion and Growth [no advection]): In this simulation, advection is turned off to quantify its effect via comparison with the previous simulation. The results show that in the absence of dilution caused by flow onto the Bank across its north flank, the Georges Bank population is quite similar to the observed distribution. Without advective loss, the coastal population grows quite rapidly and diffuses into the interior of the Gulf of Maine.
Recommended next steps for Pseudocalanus modeling:
Eventual production of 3-D maps of co-occurrence between target
species and their predators was an agreed goal for both the modeling
and the Process- Predation GLOBEC groups. Model development will
then proceed to incorporate information from day and night
differences in predator-prey distribution, which will begin to
address the behavioral component of predation.
Sunday morning and afternoon, November 10, Peter
IV. Cruise Planning Meeting
Sunday morning and afternoon, November 10, Peter Wiebe (Chairman)
A description of the Ship Schedule as it now exits was presented by Peter Wiebe (Table 2). Plans for individual cruises were described by representatives from each of the major task groups i.e. broad-scale, process vital rates of zooplankton, process vital rates of fish larvae, VPR and Sea Soar mapping, and Moorings. The schedule of cruises was reviewed and up-dates to the table were made. Descriptions of the cruise plans and sampling strategies are presented below including information about the possibility of collaborators able to conduct ancillary studies on a cruise or the need for volunteers to assist in the principal work of the cruise. There are 24 GLOBEC sponsored cruises, 4 COP cruises, and 4 Wendell Brown Gulf of Maine cruises that will take place in late 1996 and 1997.
Satellite (ARGOS) tracked 10-m and 40-m drifters will be deployed in a pattern modified to enhance the studies of GOM water coming onto the Bank in the winter/early spring period (Figure 2). As in the past, the drifters to be released on the Bank will be deployed by broad-scale cruises, while drifters to be released in the GOM will be deployed on W. Brown Mooring cruises or on VPR cruises.
|Cruise Type||Chief Scientist*|
|November 4 - 13, 1996||Albatross IV||AL9612||Process||Peter Garrahan|
|December 16 - 21, 1996||Endeavor||tbd||Sea Soar||Ken Brink/Craig Lee|
|January 6 - 18, 1997||Albatross IV||tbd||Broad-scale||John Sibunka|
|January 8 - 21, 1997||Endeavor||tbd||Process - VPR||Cabell Davis|
|January 10 - 21, 1997||Oceanus||tbd||Mooring||Ron Schlitz|
|February 11 - 24, 1997||Oceanus||tbd||Broad-scale||Erich Horgan
|February 18 - 28, 1997||Delaware||tbd||Process - VPR||Cabell Davis|
|March 2-12, 1997**||Oceanus||tbd||SeaSoar mapping||Ken Brink/Craig Lee|
|March 4 - 17, 1997||Endeavor||tbd||Zooplankton vital rates measurements||Dian Gifford|
|March 16 - 29, 1997||Oceanus||tbd||Broad-scale||Peter Wiebe|
|April 1 -10, 1997||Knorr||tbd||Moorings GLOBEC and COMP||Jim Irish/Sandy Williams|
|April 2-17, 1997||Oceanus||tbd||Fish vital rates measurements||Greg Lough|
|April 7 - 20, 1997||Endeavor||tbd||Zooplankton vital rates measurements||Larry Madin|
|April 20 - May 3, 1997||Oceanus||tbd||Broad-scale||Ann Bucklin|
|April 18 - May 3, 1997||Cape Hatteras||tbd||Process - VPR||Cabell Davis|
|May 6 - 23, 1997||Oceanus||tbd||Fish vital rates measurements||Ted Durbin|
|May 19 - 30, 1997||Albatross IV||tbd||Broad-scale||David Mountain|
|May 23 - June 5, 1997||Endeavor||tbd||Zooplankton vital rates measurements||Karen Wishner|
|June 9 - 22, 1997||Endeavor||tbd||Process - VPR||Cabell Davis|
|June 18 - 30, 1997||Albatross IV||tbd||Broad-scale||Jack Green|
|June 26 - July 5, 1997||Oceanus||tbd||SeaSoar mapping||Ken Brink/Craig Lee|
|August 16 - 27, 1997||Oceanus||tbd||Mooring||Ron Schlitz|
|October 8 - 17, 1997||Endeavor||tbd||Process - GOM||Chuck Greene|
|October 20 - 27, 1997||Endeavor||tbd||Mooring||Bob Beardsley|
|April 14 - 25, 1997||Delaware||De 9704||Process - Fish
|April 28 - May 9, 1997||Delaware||DE 9705||Process - Fish
|July 1997||Albatross IV||Broad-scale O-group gadoids||Bill Michaels|
|August - September 1997||Albatross IV||Broad-scale O-group gadoids||Bill Michaels|
|Other Collaborator Cruises to
GOM and Georges Bank|
|January 3 - 5, 1997||Endeavor||tbd||GOM Moorings||Wendell Brown
|January 31 - February 4, 1997||Endeavor||tbd||GOM Moorings||Wendell Brown
|May 14 - 15, 1997||Endeavor||tbd||GOM Moorings||Wendell Brown
|October 1 - 5, 1997||Endeavor||tbd||GOM Moorings||Wendell Brown
This report summarizes the discussions about broad-scale cruise issues that took place at the November Data Workshop and at a subsequent meeting that took place at Narragansett, RI on 26 November 1996.
The broad-scale cruises will carry out CTD, ADCP, zooplankton, fish larval, nutrient, and acoustic surveys of Georges Bank and adjacent waters in addition to the ship's suite of meteorological measurements. On each survey cruise, forty of these stations are called the "Standard Stations" (one new station has been added as described below). They are located to provide quasi-uniform, bank-wide coverage (see image at URL http://globec.whoi.edu/globec-dir/standard-stations-image-1997.html. The remaining stations are located equidistant between each pair of standard stations. At these "in-between sites", Bongo tows are taken, weather and time permitting. This protocol was started during the 1996 Broad-scale cruises and is to be continued through the 1997 field season.
There are two types of standard stations defined for broad-scale cruises:
Each "Standard Station" is assigned a priority number, from 1 to 4. Priority 1 and 2 stations are "full stations" and priority 3 and 4 stations are "partial stations". Priority 1 stations are "more important" than priority 2 stations, etc. If circumstances require the chief scientist to drop any of the core stations (due to weather or other ship delays), the lower priority stations are omitted first. All intermediate stations are to be viewed as having a priority of 5, that is, lower than the standard stations.
Once the standard stations and intermediate stations are taken, the Chief Scientist can return to interesting areas for additional station work at his/her discretion. However, given the length of the cruise, it is unlikely that there will be sufficient time for any additional stations.
Because most of the larvae will have become juveniles by the time of the last of the broad-scale cruises in June, the in-between bongos would not be worth the time. Instead, the intent will be to do the 40 standard stations, and to add a 10-m2 MOCNESS to all stations < 100 m depth (about 15 or so stations). This should maximize our sampling of the '97 cod and haddock year classes - and on ALBATROSS IV take less time than the bongos would have required.
In addition to the regular work at the broad-scale stations, some micro-zooplankton work will be done. The objective of this work is to sample the natural prey assemblage across the Bank at each CTD station and process data for micro-zooplankton size and motility spectra. To assess micro-zooplankton prey size and motility: 1) 200 ml samples are taken from each CTD cast from surface and depth Niskin bottles, 2) Size spectra and motion of each prey sample are characterized using video motion analysis, and 3) Results are plotted in both time and frequency domains.
At the 26 November 1996 meeting, issues associated with the stations, personnel, sampling protocols, equipment to be used on a cruise were discussed. The following are the results of those discussions.
Stations: Some recommendations were made for changing the location of current standard stations and for adding an additional standard station (#40). Stations 24 and 39 are very close together in western Northeast Channel. Sometimes when doing one station, the ship ends up at the other. Station 39 was added last year to be at the site of a BIO mooring. The recommendation was made and endorsed by the group to move station 24 a few miles west and south, up onto the Bank, to 41 52.5 N, 66 00.0 W, to provide a more even station coverage.
At the New Hampshire meeting the desire for more information on source waters north of the Bank was raised in some discussions. One suggestion was to move station 31, located on the northern edge of the Bank, a few miles north into deeper water. However, this would reduce the coverage of sampling on the Bank, itself. The recommendation was made and endorsed by the group to move station 31 a few miles south, up onto the bank (to 42' N; 67 37.0' W) and to add a new standard station 40 a few miles further north in the deep water of the Gulf of Maine (42 10, 67 40). Station 40 would be a priority 3 station, with a sampling routine of CTD, bongo, 1-m2 MOCNESS, and 10-m2 MOCNESS.
To obtain more ichthyoplankton sampling, bongo tows were done half way between stations on most surveys last year. The recommendation was made and endorsed to continue this sampling. The bongo sites are not specific locations. Instead the location is to be determined by the bridge as half way between where one station is completed (at the end of a 1-m2 MOCNESS or 10-m2 MOCNESS tow) and the site of the next standard station. In some cases, where standard stations are very close, the in-between bongo would not be done. After review of the new locations for stations 24, 31 and 40, John Sibunka will determine between which stations a bongo need not be done and provide that information for the Chief Scientist's manual.
In the original sampling plan, one station (originally # 38) was to be occupied twice- at the beginning and end of the cruise - primarily to provide a better time series for the small zooplankton. This re-occupation has not generally be done. Since the sorting of all of the small mesh zooplankton samples is already a problem, it was recommended and endorsed by the group that the reoccupation of a coming and going station be dropped from the Chief Scientist's manual.
The issue of what to do if a survey is completed early was discussed. It was decided that the highest priority should be to return to any high priority stations that were skipped during the survey due to weather or other problems. If no stations were skipped or distance and time do not allow returning to a skipped station, other sampling to investigate an event or condition of interest could then been done. There is no imperative to conduct sampling simply to avoid returning early.
In a related issue, the importance of returning to high priority stations that have been skipped was discussed. Returning to a skipped station might be done instead of a lower priority station later in the cruise. After station 25, during the westward progression along the northern edge of the Bank, the cruise track may come fairly close to any stations skipped earlier along the southern flank. The Chief Scientists need to consider opportunities to return to high priority stations that have been skipped.
Drifters will be deployed again this year. Specific locations and options for deployments will be provided by Dick Limeburner (Wiebe is responsible for asking Dick about the locations and which drifters will be deployed by broad-scale cruises or by other cruises).
Personnel: Volunteers are still being sought for the February, March and April cruises. David Townsend will be participating in the February through May surveys. Peter Wiebe anticipates participating with his acoustics from March through June, pending funding decisions.
Sampling Protocols: The 1-m2 MOCNESS net #0 and #5 nets are to go to 500 m on deep stations, with net#1 being opened at 500 m and net #6 being opened at 200 m on the way up. This is the same as last year. There was a question of whether the Albatross had enough conducting cable on the boom winch to enable the MOCNESS to reach 500 m (to do this at least 1000 m of wire needs to be paid out). This was to be checked and reported at the next EXCO meeting.
There were several areas of improvement discussed with respect to the OCEANUS. Last year, a paper depth recorder output was all that was available. There is, however, a need for a digital readout of the water depth in meters next to the area where MOCNESS operators are controlling the net tows, especially when the water is shallow. Also the starboard boom winch moved in and out too slowly when last used for a broad-scale cruise. This needs to be checked and improved if possible. In the area where MOCNESS is launched and recovered, the door is hinged so that it opens aft. This makes it difficult to do the launch and recovery and the nets can be easily ripped. The door should be modified so that it can be opened and secured forward of the work area. Since the sleeping van will be used on the Oceanus, there was a request that a check be made to see that the recommendations that were presented in the Oceanus 275 cruise report were carried out. Disposal of waste alcohol preservative has become an issue. A check needs to be made of how it will be handled on the Oceanus (by incineration?). Finally, the layout of the wet-lab hood and sink space where plankton samples are processed and preserved was discussed. Ted Durbin's group will discuss this with Hovey Clifford to make sure adequate facilities are available this year.
The 10-m2 MOCNESS will also go to 500 m on deep stations. On all stations the intent is to sample 4000-5000 m3 for each 10-m2 MOCNESS net.
On CTD casts, rosette samples will be collected at more depths than in previous years. David Townsend requests that 12 bottles (1.7 l) be on the rosette - with most being used on deep stations and perhaps 4-5 on shallower stations. There may not be enough 1.7 l bottles to meet the needs and P. Wiebe agreed to ask at WHOI about borrowing between 6 and 12 bottles. How depths will be selected is yet to be determined. There was also some discussion about putting a camera system (and altimeter) on the CTD so that a picture of the bottom be taken at each lowering of the CTD. The camera system would be supplied by a group at NUWC in Newport, RI. Although there was interest in seeing the pictures collected, more information is needed about the camera system and what modifications, if any, might be needed to integrate it onto the CTD frame.
The sampling protocols for Scott Gallager's work were not available for the meeting. One potential problem area is the volume of water needed from a bottle.
David Townsend will bring a light sensor to make a light cast at each station. A light cast requires about 20 minutes and will use the SEABIRD CTD (on the wire that supports the bongo net tows) to provide depth information. The intent is to find out how much effort (logistically and time) this requires and to then decide on what the standard procedure for light casts will become. There was also some discussion about whether a PAR sensor would be included with the MET package on each of the broad-scale cruises (Wiebe will find out about this for the OCEANUS).
The desirability of doing secchi disk casts was discussed. It could be accomplished during the daytime CTD or pump casts - and not require any extra time. Ted Durbin and David Townsend will look for a disk to have on cruises. The protocol for Secchi disk casts would have to be developed.
Ann Bucklin forwarded a request for three types of samples. The first two represent continuation of existing protocols: (1) alcohol preservation of the 1-m2 MOCNESS #5 net and (2) alcohol preserved splits from 1-m2 MOCNESS nets #2, #3, and #4. The third request was for splits from the pump samples from some or all of the stations where fine mesh 1-m2 MOCNESS splits (i.e., request 2) are taken. These pump splits could be done in the laboratory after the cruise. Concern was raised about the amount of time the new request would require. Ted Durbin will discuss this request with Ann to determine how it can accommodated.
Charlie Miller has requested alcohol preserved samples in January and February to study quadrithek female copepods. It was suggested that he discuss this need with Ann Bucklin to share the 1-m2 MOCNESS #5 net sample.
Erich Horgan and Larry Madin submitted a request for sampling by a Reeve net to be done to collect gelatinous animals intact. The tow would be done slowly (10 m/min) to within about 10 m of the bottom. Some processing and enumerating of the samples would be required on board. To determine if the request could be accommodated and on how many stations, more information is needed on 1) the specific on board protocol for sample processing, 2) how deep to fish the Reeve net at deep water stations, and 3) the source of needed supplies. Ted Durbin will discuss this with Larry and Erich.
No larval RNA/DNA sampling is planned for this year on the broad-scale cruises. The Durbin group plans to do RNA/DNA work on copepods along the northern edge of the Bank. This will require a ring net tow. A description of the protocol will be needed for the Chief Scientists book.
Equipment: For MOCNESS frames, the NMFS 10 m frame will be available throughout the season since Greg Lough will not be using it. The NMFS 1 m frame should also be available for much of the season. Only during May will a broad-scale cruise be at sea during a cruise by Greg. The WHOI 1 m frame will also be available. For electronics systems, there are 3 NMFS 16-bit packages and at least 2-12 bit systems. The details of the availability of frames and electronics systems needs were discussed at the December 6, 1996 EXCO meeting.
For MOCNESS nets, Ted Durbin has sufficient 150 um mesh nets for the season. Jack Green has a set of unused 333 um mesh nets, but needs to confirm their condition. For 10 m nets, Greg Lough has 8 good nets and Erich Horgan has a number in various condition. An accounting of the nets and their condition was discussed at the December 6 EXCO meeting.
Buckets for the MOCNESS systems are in short supply. Due to losses over the last two years, some new buckets will need to be purchased. Tony Chute will work with Betsy Broughton to determine how many buckets NMFS presently has.
The batteries for the MOCNESS systems both for 12-bit and for 16-bit systems are also in short supply. Several will need to be purchased for the 1997 field year.
The set up of MOCNESS systems on cruises was discussed. Too often the responsibility has fallen to Erich Horgan, somewhat by default or at the last minute. A better scheduling - in time and personnel - needs to be arranged this year in setting up the systems for cruises. Training of a few selected individuals should be done to accomplish this. P. Wiebe will talk with Barrie Walden about this for cruises on the OCEANUS.
The availability of bongo net systems also may become an issue, because of overlapping needs of the COP program, the NMFS Ecosystem Monitoring program and broad-scale surveys. A counting of net frames and associated equipment needs to be done in coordination with these other programs.
The fluorometer used on the CTD system has an internal filter, with an adjustable time constant - which has been set at 3 seconds, as recommended by the manufacturer. Analysis of earlier data suggests that this is too long to accurately represent peak values in the pycnocline. The time constant will be reduced to either 0.1 or 1.0 seconds. Comparison of the fluorescence data sets from different years will need to take this change into account.
Data Logging: Existing logging protocols use only a start time entry in the log for operations during which the vessel is stationary - CTD casts, pump casts, ring net tows, etc. The usefulness of having a start and end time entry was discussed. Since any change would need to be program-wide, this was discussed at the December 6 EXCO meeting and a decision was made to record the start and end information for all events.
When a tow is aborted and no samples are taken and then the tow is re-done, no separate event for the aborted tow should be logged. The fact that there was an aborted tow should be noted as a comment in the event line of the successful tow.
A standardized recording of along track data on a 1 second schedule was recommended for all cruises.
To avoid confusion of event times, all computer clocks should be synchronized with the ship's computer network time at the beginning of the cruise and checked regularly. This should be added to the Chief Scientist's manual.
Post Script: The combined total of time that the
requested and recommended new sampling will require has not be
calculated. The cruises in 1997 are 1 to 2 days longer than in past
years, so the addition of some new requirements should be able to be
done. After more information is obtained on some of the requests
made, a follow-up discussion (in person, by phone or by e-mail) will
be needed before the January cruise to provide guidance to the Chief
Zooplankton Vital Rates
March 4-17 1997: R/V ENDEAVOR
PIs: Dian Gifford (Chief Scientist), Mike Sieracki, Scott Gallager, Karen Wishner, Percy Donaghay.
The March 1997 Zooplankton Vital Rates cruise will apportion effort among four program components:
Hydrography. The crest-to-Slope Water hydrographic section ("Southern Flank Section"), consisting of approximately 12 stations, will be completed as on the 1995 process cruises. A volunteer hydrographer will be provided by Bob Beardsley.
Naupliar feeding and prey field (Dian Gifford and Mike Sieracki). The specific objective of this component is to describe quantitatively the contribution of nano- and microplankton prey fields to recruitment of target copepod populations onto the Bank. It is hypothesized that early stage copepods advected onto the Bank from the Gulf of Maine and the Great South Channel experience an enriched food environment on-Bank relative to source regions. Studies will be done at 4 paired off-Bank/on-Bank stations: the Great South Channel/northern bank edge; Georges Basin/northeast peak; Bank crest/southern flank on either side of the tidal front; and within/without the Scotian Shelf cold plume, if present (Figure 5). Objectives are a) to characterize the water column (hydrography, size-fractionated chlorophyll, nano- and microphytoplankton, nano- and microzooplankton, nutrients) using a CTD/ rosette sampler equipped with 10-L Teflon-lined Go-Flo bottles and b) to perform feeding experiments with nauplii of the target copepods. Ingestion rates of stage N3 - N6 nauplii will be measured directly in shipboard experiments using natural prey assemblages. The proximate influence of omnivorous feeding will be interpreted in the context of in situ prey field and advective regime. Ultimately, the influence of plant versus animal prey in consumer diet will be addressed in the context of measurements made by other investigators of consumer distribution, condition, life history parameters and production.
Larval cod feeding (Scott Gallager). Objectives are a) to sample the natural prey assemblage at various sites across the Bank including the Northeast Peak, the Crest and the Southern Flank and characterize the microplankton size and motility spectra and b) to incubate newly hatched cod larvae in samples of the natural prey assemblage in situ attached to free-drifting drogues. A minimum of eight, 3-hour deployments at random intervals throughout the day and night over the extent of the cruise will be necessary. Grazing rates of larvae feeding on soft-bodied prey (protozoans) will be estimated using fluorescently stained prey and on-board quantitative epifluorescent microscopy.
Role of episodic advective features in the input and loss of zooplankton on Georges Bank (Karen Wishner and Percy Donaghay). The objective of this component is to determine the association of particular zooplankton species or life stages with selected features of opportunity and how zooplankton vertical migration interacts with the flow field to affect the flux of zooplankton in these features. Features will be targeted using satellite imagery, and their water mass composition will be determined by both standard hydrographic techniques as well as the use of a SAFire spectral fluorometer to obtain characteristic bio-optical signatures. Zooplankton will be sampled with vertically-stratified MOCNESS tows day and night inside and outside of advective features. CTD casts and the spectral fluorometer on the 1-m2 MOCNESS will provide physical and bio-optical signatures of water masses. This will allow documentation of the degree of association of target zooplankton species with the water and bio-optical signature of the advective feature throughout the day/night cycle. Combining information on transport (from shipboard ADCP as well as any nearby moorings or drifters) and zooplankton concentrations will provide estimates of the instantaneous flux of zooplankton associated with these features. By looking at a variety of features across a seasonal gradient and at different locations, data will be obtained about a range of scenarios.
This information will be analyzed within the context of studies by others on vital rates, genetics, broad-scale distributions, physical oceanography, and modeling to provide an overall mechanistic understanding of the potential impact of episodic zooplankton input or loss on the target populations of plankton and fish on Georges Bank. On the vital rates cruises, features that will likely be sampled include the northern edge of the Bank, the tidal mixing front, and episodic Scotian Shelf water filaments or other features of opportunity. The first two types of features will be present on all cruises and sampling for these will fit in with Dian Gifford's locations and the hydrographic transect. A few days on each cruise will be reserved to chase episodic features of the third type.
April 7-21 1997: R/V ENDEAVOR
PIs: Larry Madin (Chief Scientist), Dian Gifford, Mike Sieracki, Karen Wishner, Percy Donaghay, Grace Klein-MacPhee
The April Zooplankton Vital Rates cruise will apportion effort among four program components:
Hydrography. As described above for the March cruise.
Naupliar feeding and prey field (D. Gifford and M. Sieracki). As described above for the March cruise.
Role of episodic advective features in the input and loss of zooplankton on Georges Bank (K. Wishner and P. Donaghay). As described above for the March cruise, on the second cruise, operation of the 1-m2 MOCNESS will be shared with the Madin / Sullivan / Klein-MacPhee group, and we will coordinate sampling locations and sample analyses.
Predation studies (L. Madin, S. Bollens, B. Sullivan and G. Klein-MacPhee). The Predation Group plans to compare diversity and abundance of predatory species on and off the Bank by sampling during this cruise along 2 transects: 1) from the central region across the northern margin and into the Gulf of Maine; 2) from the eastern edge of the Bank towards the Scotian Shelf. Sampling at stations at the ends and midpoints of these transects (see Figure 6) would be done with the 1-m2 MOCNESS and 10-m2 MOCNESS systems. Replicate day/night pairs will be taken whenever possible, and 1-m2 MOCNESS sampling will be coordinated with Wishner/Donaghay for efficiency. In addition to distribution of predators, estimates of instantaneous feeding rates based on gut contents analysis will be made at each station. Further collection of predators for gut contents or live experimental work will be made as possible using nets and SCUBA diving; these collections are not site-specific and can be opportunistic. Shipboard incubations to determine feeding rates and/or digestion times of predators will also be conducted.
May 23-June 5 1997: R/V ENDEAVOR
PIs: Karen Wishner (Chief Scientist), Dian Gifford, Mike Sieracki, Larry Madin, Percy Donaghay, Barbara Sullivan, Steve Bollens.
The May/June Zooplankton Vital Rates cruise will again apportion effort among four program components:
Hydrography. As described above for the March cruise.
Naupliar feeding and prey field (Gifford and Sieracki). As described above for the March cruise.
Role of episodic advective features in the input and loss of zooplankton on Georges Bank (Wishner and Donaghay). As described above for the March cruise.
Predation studies (Madin, Bollens, Sullivan and
Klein-MacPhee). The work will be largely as described above for the
April cruise, but with sampling along a third transect from the
southern flank out into slope waters lying to the south instead of
along the earlier transects (Figure 7). In
addition to the MOCNESS sampling described above, the Predation
group plans to deploy the Large Area Plankton Imaging System (LAPIS)
at some stations to video-sample ctenophores, siphonophores and
other delicate gelatinous forms. This device is designed to be
towed at 2 knots. Another goal (pending separate NOAA funding) is
the use of an ROV to survey regions of the bottom for the presence
of hydroid colonies (Clytia spp.) which may be sources of
the suspended hydroid colony fragments found on the Bank. The ROV
use, which will be supported by 2 specialized staff from the
University of Connecticut NURC, will be used principally on the
transect from the flank southward. This line will traverse areas
which are open and others which are closed to bottom trawling, and
it is hoped that comparison of benthic hydroid distribution in these
areas will test a hypothesis that bottom trawling dislodges and
re-suspends a significant number of hydroid colonies, and is partly
or wholly responsible for their presence over the central parts of
the Bank. SCUBA collections will also be made as time and weather
Larval fish advection, dispersion, growth, and mortality (G.
Lough, L. Buckley, L. Incze):
Calanus growth, production, and mortality (R. Campbell,
T. Durbin, M. Ohman, J. Runge):
Larval cod feeding (S. Gallager):
The OCEANUS fish/zooplankton process cruises will be conducted
in four phases:
The May cruise will be different from the April cruise in three
Fish and Zooplankton Process Cruises:
PI's Greg Lough (Chief Scientist), Larry Buckley, Bob Campbell, Ted Durbin, Scott Gallager, Lew Incze, Mark Ohman, Jeff Runge.
April 2-17, 1997 and May 6-23, 1997
Video Plankton Recorder Cruises (Cabell Davis)
Larval fish advection, dispersion, growth, and mortality (G. Lough, L. Buckley, L. Incze):
Calanus growth, production, and mortality (R. Campbell, T. Durbin, M. Ohman, J. Runge):
Larval cod feeding (S. Gallager):
The OCEANUS fish/zooplankton process cruises will be conducted in four phases:
The May cruise will be different from the April cruise in three ways:
The principal goal of the work on these is to measure the transport of the copepods Calanus and Pseudocalanus across the boundaries of Georges Bank.
The VPR group has proposed to quantify major processes affecting transport of copepods on/off Georges Bank by conducting four VPR survey cruises in source and retention areas along the northern and western edges of the Bank and by collaborative analysis of data from proposed SeaSoar/VPR surveys (Brink et al.) of ring/eddy induced losses to the south. VPR surveys conducted during January and February along the entire northern edge of the bank will explore quantitatively the processes controlling inflow of "seed" populations to the bank. VPR surveys during April and June will focus on the processes controlling retention/loss of copepods along the western region of the Bank as a result of gyre closure due to the onset of stratification. Surveys during these latter cruises also will be conducted along the northern inflow region to quantify direct inflow of the large GOM Calanus population onto the Bank. In the collaboration with the proposed Brink et al study, we will analyze environmental and plankton distributional data obtained from a VPR mounted on the SeaSoar to quantify off-bank transport of copepods by ring-detrainment along the southern edge during March and July.
To identify and quantify processes affecting transport of copepods onto the bank, three types of field sampling will be employed. 1) To obtain a high resolution map of the hydrography, currents, and copepod abundances, we will conduct a VPR towyo survey in a zigzag course along the entire northern edge of the bank from the Great South Channel to the Northeast Channel (Figure 8). 2) To resolve tidal components of copepod transport, we will towyo the VPR along three triangular transects across the bank edge, each transect being sampled 12 times during the day (two tidal cycles) (Figure 8). 3) To quantify event scale transport of copepods onto the bank, opportunistic Lagrangian mapping of dominant features observed during the zigzag survey will be conducted. The first and third types of sampling will be conducted during January and February cruises to quantify the input of seed populations to the bank. The tidally- resolved sections will be conducted during all cruises in order to quantify seasonal changes in tidal flow and copepod flux. The zigzag survey will be conducted once during the April and June cruises to quantify the on-bank flow of the large GOM Calanus population in this region.
We will examine the degree to which Calanus and Pseudocalanus are retained on the Bank by recirculation relative to their fine-scale vertical and cross-shelf distributions using a combination of tidally-resolved transects, Lagrangian sampling, and grid surveys. Since the degree of re-circulation is apparently related to the intensity of density stratification (GLOBEC, 1992), this sampling will be conducted during April and June. These months represent pre- and post-stratification periods during which copepod populations should be differentially retained on the Bank. Processes affecting transport of copepods into this region from the east and out of the region to the north (retained on the Bank) versus west (lost from the Bank) will be examined in a series of steps.
First, to characterize the hydrography, currents, and copepod abundances entering the re-circulation area and to directly calculate the flux of copepods into this region, we will conduct a series of 12 tidally-resolved VPR towyo transects (40 km each) along the north-south mooring line of Schlitz et al. (Figure 8) over the course of one day. During the second transect, we will deploy a surface (10 m drogue) and deep (40 m drogue) GPS drifter at the 65, 75, and 85 m isobaths in order to examine the transport through the re-circulation region and to quantify vertical migration if it exists. Second, after the 12 transects have been completed, we will conduct a time-series of 6 towyos around the drifters over a one day period to measure the vertical migration behavior. Third, after the initial transect and drifter sampling are completed, we will conduct repeated high-resolution grid surveys over the entire re-circulation area (Figure 8). This grid will take about one day to complete and will be repeated 3-4 times during each cruise. Transit time of the drifters through this area is about 5-6 days, so that the repeated grid sampling will take place as the drifters move through the region. After the grid sampling is completed, we will conduct a series of 12 tidally-resolved VPR towyo transects along the east-west mooring line to measure the flux of copepods out of this region. The multiple realizations of the high-resolution 3-D grid and the tidally resolved transects will allow us to obtain time-dependent information on the relative importance of northward versus westward transport of the copepods through this area as a function of their fine-scale horizontal and vertical position.
Fluxes onto and off the Bank will be calculated from the
de-tided ADCP data and the copepod abundance data. The ADCP
velocity data will be de-tided using the empirical methods of J.
Candela as well as the tidal model of D. Lynch which will be
expanded to contain multiple tidal components. These estimates of
the tidal flow will be subtracted from the ADCP data to obtain the
net flow. The moored array of Schlitz et al. (Figure 8) also will provide information on tidal
flow that can be used in de-tiding the ADCP data. Additional
spatial data of the re-circulation will be provided by the long-term
drifters of R. Limeburner et al., and we will examine satellite IR
data for the presence of dominant small-scale features that could
SeaSoar Surveys (Ken Brink and Craig Lee)
|16-21 Dec 1996||Engineering|
|2-12 Mar 1997||Event Driven Surveys - unstratified|
|26 June - 5 July 1997||Event Driven Surveys - Stratified|
The SeaSoar cruises will investigate several possible mechanisms for removing water off the southern flank of Georges Bank, focusing on Gulf Stream ring - shelf break front interactions, wind-driven deformation and mixing of the front, and the generation of eddies thorough frontal instability. Our goals are to examine the physics of these mechanisms and to evaluate their role in transporting target species off the Bank. Observations will be collected using a towed undulating profiler carrying temperature, conductivity, transmissometry, and chlorophyll fluorescence sensors, along with a video plankton recorder (C. Davis and S. Gallager) and a Tracor Acoustic Plankton Recorder (M. Berman). Velocity observations will be made using shipboard ADCP, GPS, and phase-carrier GPS heading measurements.
Sampling during the SeaSoar cruise will be event-driven, with the highest priority given to Gulf Stream ring interactions. As such, we will be highly dependent on satellite imagery (J. Bisagni) for determining our final sampling plans. A typical survey would consist of a repeated "radiator" pattern with spatial and temporal scales chosen according to the feature of interest. Preference will be given to events which occur near the moored array on the southwestern end of the Bank (R. Schlitz).
Limited bunk space will be available and it may be possible to
accommodate additional scientists/projects on a not-to-interfere
basis. Please contact Craig Lee © firstname.lastname@example.org, (508)
289-2541) for further information.
Great South Channel Mooring Cruises (Ron Schlitz)
January 1996 R/V OCEANUS.
An array of nine moorings will be deployed in the vicinity of the Great South Channel. CTD data will be collected at all mooring sites for instrument calibration.
There will be a follow-up cruise in August to recover the
Long-Term Mooring Cruises (Jim Irish/Bob Beardsley)
April KNORR: Jim Irish and Sandy
Williams will conduct a joint GLOBEC/CM&O cruise to recover and deploy moorings at the GLOBEC Georges Bank southern flank site SF and at the CM&O mid-shelf site on the New England shelf. CTD data will be collected at both mooring sites for instrument calibration, plus at least once along the southern flank standard mooring transect. Space is available for other investigators.
October ENDEAVOR (Jim Irish). The objective of this cruise will
be to recover and replace the long-term moorings at the GLOBEC
southern flank site SF, and collect CTD data along the standard
southern flank mooring transect. Space is available for other
COP 1997 Georges Bank Predation Field Studies (Bill Michaels)
The main objective of the NOAA Coastal Ocean Program's (COP) 1997 field studies is to estimate predation mortality on cod and haddock during their first year of life history by their fish predators on Georges Bank.
The first two COP cruises (DE 97-04 and DE 97-05) will examine pelagic fish predation on larval cod and haddock on Georges Bank during April 14 - 25 and April 28 - May 9, 1997. Density distributions of larval gadoids (i.e., cod and haddock), their pelagic fish predators (e.g., mackerel and herring), and hydrography will be sampled simultaneously throughout a fine-scale grid survey of approximately 50 stations from southern to northeastern Georges Bank (Figure 9). The grid will be replicated weekly during the four week study to examine spatial changes of predation mortality in relation to the southwesterly drift of fish larvae and northeasterly migration of fish predators.
At each station, a 61 cm bongo (fitted with 0.333 and 0.505 mm plankton nets) with an attached CTD will be towed double-obliquely (tow-yo) at 1.5 knots according to standard MARMAP procedures. A larger ichthyoplankton sampler (5 m Methot trawl) also will be fished obliquely at 2.5 knots for post-larval gadoids. Immediately after each bongo/CTD and Methot haul, pelagic fish predators will be sampled using a commercial Gourock midwater trawl (500 m opening). Acoustical survey of fish predators using the Simrad EK500 echo-integration (12, 38, and 120 kHz) system will be conducted continuously throughout the study. Various oceanographic, meteorological, and navigational measurements will also be measured continuously by the SCS and ADCP systems. Real-time AVHRR images will be available from the vessel's Qfax to ensure that shelf-slope gradients are incorporated into the grid survey. However, location of the grids will depend primarily on the density distribution of larval gadoids as determined from the ichthyoplankton sorting at sea. Stomach contents of pelagic fish will be preserved for detailed microscopic and DNA analysis for larval fish prey in the laboratory.
In addition, fish predation on age-0 cod and haddock during their transition from pelagic to early-demersal phase will be investigated during two COP cruises aboard the NOAA R/V ALBATROSS in early-July and late-August 1997. Each cruise will involve a systematic survey across Georges Bank, possibly with some fine grid sampling in the northeast region, using the 5 m Methot, bottom trawl, midwater trawl, CTD, and echo-integration.
COP Predation (NMFS) and the WHOI Predation Group anticipate proceeding toward achieving an integrated field effort for collection and preservation of fish and invertebrate samples for gut content and immunological analysis. Specifically, finer Bongo net mesh sizes and use of EtOH vs. formalin for sub-samples was discussed. Also, the possibility exists for assigning a WHOI Predation volunteer on the COP DELAWARE cruises in April-May 1997 to assist in sample procurement, sorting, and preservation.
Contact Bill Michaels (chief scientist of COP cruises) regarding
availability of berthing and to submit special sampling requests.
Wendell Brown Cruises to the Gulf of Maine
There will be four cruises to the Gulf of Maine, as part of an NSF-supported research program on "Wintertime convection and water mass formation in the Gulf of Maine" being conducted by Wendell Brown (UNH).
January 3-5 1997, R/V ENDEAVOR: The objective of this cruise is the deployment of a current meter/conductivity/temperature mooring with telemetry in Wilkinson Basin (270 m) along with a bottom pressure instrument. In addition, there will be dragging for gear lost in Wilkinson Basin and a hydrographic transect from the mooring deployment site inshore to Cape Porpoise.
January 31 - 4 February, 1997, R/V ENDEAVOR: The objective of this cruise is the deployment of an ADCP/T-chain mooring with telemetry in 160 m in Jeffery's Basin along with a bottom ADCP/pressure instrument. In addition, there will be a regional hydrographic survey of Wilkinson Basin.
May 14 - 15, 1997, R/V ENDEAVOR: The objective of this cruise is to conduct a regional hydrographic survey of Wilkinson Basin.
October 1 - 5, 1996, R/V ENDEAVOR: The objective is this cruise is to conduct a regional hydrographic survey of Wilkinson Basin and to service the moorings.
There will be bunk space available for individuals and time for
some add-on bottle sampling during the hydrographic surveys.
Current arrangements do not include the use of a rosette bottle
sampling system (for budgetary reasons), but if ancillary program
scientists wish to make that arrangement, it could probably be used
without significantly slowing the planned sampling.
V. Data Management Discussion
Monday morning, November 11, Peter Wiebe (Chairman), Bob Groman (Rapporteur).
On Monday morning, November 11, 1996, a plenary session was held
to focus on several data management topics. First, the Chair
requested possible topics to discuss, such as data access, software
tools for data visualization, event logging, local vs. UTC
(Universal Time Code) time of observations, year-day convention, and
serving field, model and satellite data. Second, we addressed those
areas of most interest or concern. A summary of the discussion
On-line data: The workshop participants discussed when
data should be placed on-line. Consistent with the U.S. GLOBEC
Data Policy, the answer is "when the data will be useful to others,
even if not final." We also saw the need to provide "decimated
data"; that is, for data collected at a high repetition rate,
provide access to a decimated version of these data for initial
viewing. We also discussed the benefits of serving figures and
images of processed data. This is already being done by Jim Manning
and the NMFS wind stress data and processed satellite images.
On-line data: The workshop participants discussed when data should be placed on-line. Consistent with the U.S. GLOBEC Data Policy, the answer is "when the data will be useful to others, even if not final." We also saw the need to provide "decimated data"; that is, for data collected at a high repetition rate, provide access to a decimated version of these data for initial viewing. We also discussed the benefits of serving figures and images of processed data. This is already being done by Jim Manning and the NMFS wind stress data and processed satellite images.
Much data still needs to be added to the on-line system. The Physical Oceanographers developed a table of data and who to contact (Appendix III). This information will be given to Bob Groman to add to the on-line data inventory (http://globec.whoi.edu/globec-dir/inventory.html) in order to provide information about data availability and the responsible person.
Coastal Ocean Program data will also be available soon, and
direct access to these data via our system is planned.
Display Software: There was a lively discussion about
what, if any, additional software display tools should the program
office make available, and directly accessible (and usable) via the
Web server. Availability of data visualization tools is one area
that several participants felt would be very important to our
project as investigators want to pull together physical (such as
water temperature, salinity, and current speed) and biological (such
as predator and prey field) data sets.
Display Software: There was a lively discussion about what, if any, additional software display tools should the program office make available, and directly accessible (and usable) via the Web server. Availability of data visualization tools is one area that several participants felt would be very important to our project as investigators want to pull together physical (such as water temperature, salinity, and current speed) and biological (such as predator and prey field) data sets.
Initially, participants felt that the data system should only provide direct access to the database from MATLAB and a library of useful MATLAB M-files. (Downloading of flat, ASCII files and MATLAB formatted ".mat" files is currently supported by the database. It is also possible to directly access the database from within MATLAB running on Unix platforms, using the "loadjg" command.) There should also be a simple way to browse the database from within MATLAB, from all platforms. People also wanted to be able to get information about data available via a geographical representation and user interface. The focus of the data management office should be to get the data on-line, provide means to "join" data sets, but let individual investigators worry about visualization issues. The Web site would also maintain a directory of useful software packages that people could download to their own computers.
However, after additional discussion, people believed that there would be much to be gained if platform and software independent means were developed to visualize our data sets. The Visual Basic program demonstrated by David Mountain was thought to be a very useful tool. This PC-based software displayed the station locations, and by clicking on the station, one could view a number of x-y plots. Later, Glenn Flierl provided a demonstration of a similar capability that could be provided using MATLAB software. Several participants felt that the preferred solution should be independent of what software is available on a local machine. This meant that the central Web server must be able to serve a graphical data browsing capability, in a similar way that we can now generate x-y data plots and simple listings.
Other ideas mentioned that could augment a graphical output
capability included the Mapquest software and the LinkWinds software
available from the Jet Propulsion Laboratory. Also, the efforts of
the DODS Project should be followed closely as a means to enhance
direct access to on-line data from within any software application.
Mirroring the Database: It would be beneficial if our
Web site (including the database) were "mirrored". That is, access
to the U.S. GLOBEC Georges Bank home page and data would be
available from more than one site. This can improve performance as
well as provide improved accessibility, as for example, when one
site is down or a server network is unreachable. There is currently
the ability to use another computer system at WHOI to provide access
to our home page when the primary server is down. This was used,
for example, when the main server was upgraded in early 1996.
However, full mirroring capabilities would require a significant
commitment of time and resources. Event Log Training: The event log spreadsheet and macro,
based on the Quattro Pro (version 6) software, is available to all
program participants. Its use is encouraged in order to provide a
consistent set of event log data for all cruises. As in the past,
training in its use will be provided to any chief scientist and
their designates. Summary of High Priority Action Items: The following
data management tasks were identified as high priority by the
Mirroring the Database: It would be beneficial if our Web site (including the database) were "mirrored". That is, access to the U.S. GLOBEC Georges Bank home page and data would be available from more than one site. This can improve performance as well as provide improved accessibility, as for example, when one site is down or a server network is unreachable. There is currently the ability to use another computer system at WHOI to provide access to our home page when the primary server is down. This was used, for example, when the main server was upgraded in early 1996. However, full mirroring capabilities would require a significant commitment of time and resources.
Event Log Training: The event log spreadsheet and macro, based on the Quattro Pro (version 6) software, is available to all program participants. Its use is encouraged in order to provide a consistent set of event log data for all cruises. As in the past, training in its use will be provided to any chief scientist and their designates.
Summary of High Priority Action Items: The following data management tasks were identified as high priority by the participants:
Monday afternoon, November 7, Peter Wiebe (Chairman/Rapporteur)
A strategic planning session was held to discuss possible steps in the development of Phase III of the Georges Bank Program. Such planning needs to begin now because the time line for preparation of an Announcement of Opportunity for Phase III and its official publication should occur by about June 1997 if proposals are to be prepared, reviewed, and funded in time to prepare for the next major field season in 1999. During the meeting, discussion focused on:
The implementation plan upon which the Georges Bank Program has been predicated created a context for three major field efforts which were to focus sequentially on:
as the principal agents for creating and maintaining the biological structure on the Bank. This work was to be done in a way that enabled rate processes and spatial distribution of the target species to be coupled to the dominant physical processes affecting the system as well as their predators and prey. It was recognized that there is a need to better identify areas of field work required for input to modeling effort (both biological and physical), a need for better tidal models, and a need for coordination of proposals in Phase III from viewpoint of data assimilation and modeling. In the discussion it was also recognized that there are Phase II studies that relate to cross-frontal exchange and will provide a background for Phase III. The Phase III work will, however, require much more intensive physical and biological instrumenting of fronts. The Phase III effort is also important from the modeling viewpoint. Modeling efforts in Phase II will make model predictions about the dynamics of frontal exchange and these will need to be tested. Further, inter-annual variability in the PO fields was dramatic between 1995 and 1996. Whether the same level of variability exists in the biological data sets remains to be seen (this is an area of active research). There is, for example, a need to examine biological data for possible differences in 0-Group cod and haddock, spawning biomass and egg distribution and abundance (1996 not yet funded).
To justify Phase III, a background document that summarizes the current status of inter-annual variability of water properties, plankton biomass and species, fish larvae, and fish stocks. It needs to demonstrate the progress that is being made on big issues involving the physics and biology of Georges Bank and the models that are being developed to understand plankton and fish dynamics. The document should identify where the gaps are in the "primitive" models as they exist now. In the discussion it was recognized that to date larval fish interactions with their environment are under studied in this program and that issues such as diet and effect on growth rates via otolith studies need more emphasis. The document should portray the new and important insights in the dynamics of this system and biological recruitment processes.
Recommended next steps in AO preparation:
M.R. Droop. 1973. Some thoughts on nutrient limitation in algae. J. Phycol. 9: 264-272.
M.M. Mullin, 1963. Comparative ecology of the genus Calanus in the Gulf of Maine. Harvard University Ph.D. Thesis, 97 pp.
R. Beardsley, A. Bucklin, C. Davis, J. Irish, G. Lough, D.
Mountain, P.Wiebe. 1992. GLOBEC Northwest Atlantic Implementation
Plan for the Georges Bank Study. Report Number 6. 69pps.
APPENDIX I. Meeting Agenda
Great Bay RoomDay 1 (Tuesday, November 5, 1996) Set up (e.g. network connections will occur throughout the day 1500 Plenary session Organizational meeting Review workshop objectives, goals, and products Set up initial working groups 1800 Reception (main dining room) 1900 Dinner (main dining room) Day 2 (Wednesday, November 6, 1996) 0900 Working group meetings - disciplinary meetings (e.g. Physical Oceanography, Population Structuring, Population rates, Modeling) Define goals and strategies 1200 Lunch 1300 Plenary session Overview of program's goals and current status Brief reports from working groups Form additional working groups if needed 1530 Break 1600 Lecture: Modeling evenings Individual and small groups to work on data sets Day 3 (Thursday, November 7, 1996) 0830 Working group meetings - disciplinary meetings Modeling - focus on circulation Physical Oceanography - Population Rates - Population Structuring - 1200 Lunch 1300 Plenary session - cross disciplinary Brief reports from working groups Open discussion 1530 Break 1600 Lecture: Biology, zooplankton and fish evenings Individual and small groups to work on data sets Day 4 (Friday, November 8, 1996) 0830 Plenary meeting - Discuss election of Executive Committee. Distribute nominating committee ballot to attending electorate and via email (for those not attending) 0900 Working group meetings - disciplinary meetings Modeling - focus on fish Physical Oceanography - Population Rates - Population Structuring - 1200 Lunch 1300 Plenary session - cross disciplinary Brief reports from working groups Open discussion 1530 Break 1600 Lecture: Physical Oceanography evenings Individual and small groups to work on data sets Day 5 (Saturday, November 9, 1996) 0830 Working group meetings - disciplinary meetings Modeling - focus on zooplankton Physical Oceanography - Population Rates - Population Structuring - 1200 Lunch 1300 Plenary session - cross disciplinary Brief reports from working groups Open discussion 1530 Break 1600 Lecture: Vital Rates 1800 Reception 1900 New England Clambake Day 6 (Sunday, November 10, 1996) 0930 Plenary session Cruise Planning 1200 Lunch 1300 Plenary session Cruise Planning evenings Individual and small groups to work on data sets Day 7 (Monday, November 11, 1996) 0830 Plenary session Synthesis talks 1200 Lunch 1300 Plenary session Synthesis talks evenings Individual and small groups to work on data sets Day 8 (Tuesday, November 12, 1996) 0830 Plenary session Synthesis talks 1000 Break 1030 Plenary session: workshop wrap-up and discussion of plans for additional synthesis/publication preparation 1200 Workshop ends Lunch will be provided after the close of the workshop.
1. Breakfast is served from 0700 - 0930 and lunch is served from 1130 - 1330. Unless otherwise noted, dinner is served from 1730 - 1930.
2. Photo copies and transparencies can be made at the New England Center for a charge of $.10 and $.75, respectively.
3. Incoming Fax(s) - $1.00 per page. The cost is $.50 per page over 20 pages. The FAX number for the Conference is 603-862-4351. There is also a FAX at the hotel. Its number is
4. Outgoing Fax(s) - $2.00 for the first page, 1.00 for each additional page. There is no charge for the cover sheet if additional pages follow.
5. International Outgoing Fax(s) - $10.00 for the first page, 1.00 for each additional page.
6. Phone messages will be posted on a bulletin board located
outside the meeting room. The New England Center's phone number to
leave messages is 603-862-2712.
APPENDIX II. List of Workshop Participants.
|Jeff Van Keuren||x||x||x|
A Status Report
Point of Contact
|< p align=center>Moored Array Data|
|NP||Currents, T,S||Peter Smith
|S2||Currents, T,S||Jim Manning (email@example.com)||Complete||GDA|
|CR||T,S, Optics||Jim Irish
|SF||Currents, T,S, Optics||Jim Irish|
|NS||Meteorological||Carol Alessi||Complete to June 1996||FTP
|GB||Wind Stress||Jim Manning||1975-1995||GDA|
|NS||Wind Stress||Jim Manning||1975-1995||GDA|
|Broad-scale||Dave Mountain (firstname.lastname@example.org)||Complete||GDA|
Jim Irish (email@example.com)
|Process||Dick Limeburner (firstname.lastname@example.org)||Complete||GDA|
|Dick Limeburner||Complete 1995||GDA|
Underway Ship Data
Shipboard ADCP Data
AVHRR Satellite-derived SST Images
|Gridded OI||Jim Bisagni||Complete 1995||Bisagni's
GDA = GLOBEC Data Archive (GLOBEC Homepage: http://globec.whoi.edu)
OI = Optimal Interpolation
* Bisagni's Home Page: http://Kraken.gso.uri.edu/bisagni.html