Report of the

U.S. GLOBEC Georges Bank

Science Meeting

18 - 20 November 2003, Rhode Island

 


Cover Page

Acknowledgements

Introduction

Narrative

Presentation Abstracts

Poster Presentations

Appendix I: Agenda

Appendix II: List of Participants

Appendix III: List of Planned Publications

NARRATIVE

The workshop began at mid-morning on Tuesday, 18 November 2003, on a pleasant fall day that was clear and relatively warm. The meeting was opened in the Laurel Lodge meeting room by Peter Wiebe who briefly reviewed the years of field work that preceded the synthesis phase of the program, described the objectives and goals of the workshop, reviewed the agenda and structure of the workshop, and presented some ideas about future events that will concern the investigators in the coming year. Participants were reminded about the upcoming scientific meetings that should be used as forums to present the developing synthesis results. Four meetings were described as appropriate forums in which to communicate the findings:

• AGU Ocean Science Meeting, January 2004, Portland, Oregon

• ASLO/TOS Science Meeting, February 2004, Honolulu, Hawaii

• ICES/GLOBEC Symposium on the influence of climate change on North Atlantic fish stocks (11-14 May 2004 Bergen)

• ICES Annual Science Conference - Vigo, Spain September 2004

There was also a brief summary of the second phase IV Announcement of Opportunity (AO) that was reviewed at the last U.S. GLOBEC Scientific Steering Committee (6, 7 November 2003) and with some modification should be posted by next spring. This AO will target for funding aspects of the synthesis not covered by the existing projects.

Mention was made of the JGR Special Section which should be published at the end of 2003 with sixteen US GLOBEC Georges Bank program papers covering a range of physical and biological topics. In addition, plans for the next Scientific Investigators Meeting in the late spring or early summer were reviewed.

A series of twenty minute overview talks presented by the lead Principal Investigator for each of the five projects were completed during the morning. In the afternoon, shorter 15 minute talks were presented with the main focus on the descriptive physical results, modeling developments, and modeling results. After each talk, 5 minutes were scheduled for questions and discussions. The afternoon talks were followed by a reception in the Sycamore Lodge and a lovely buffet dinner.

In the evening, the group reconvened in the Laural meeting room to discuss topics raised during the day in a plenary session that finished about 2200.

Much of the second day also consisted of a series of biological and physical talks by the investigators in the five projects. Recurrent themes were present in a number of the talks. Areas of overlap between the projects became apparent and became the focus of late afternoon and evening plenary discussion sessions.

During the morning of day 3, D. McGuillicuddy provided some insight into the elements that made the JGOFS synthesis a success as well as some of the problems that were encountered. There was also discussion of the future joint investigator initiatives including production of a volume of collected US GLOBEC Georges Bank Program papers, discussion of plans for the next investigator meeting, and a discussion of follow-on science programs in the Gulf of Maine - Georges Bank - Mid-Atlantic Bight region led by K. Brink.

A total of 39 presentations (33 talks and 6 posters) were made during the first two days of the workshop.

TOPICS DISCUSSED IN PLENARY SESSIONS

Standardized Grids of broad-scale data sets. The broad-scale synthesis investigators previously created a subgroup to develop a grid of points that could be used to map the variety of data types produced on the thirty broad-scale cruises. Such a grid was produced and is now present on the GLOBEC database along with background information about it at: http://globec.whoi.edu/globec-dir/phase4doc/grid/grid_report.html. In addition, five sub-bank regions were defined based on the positions of the broad-scale stations and a knowledge of the processes that differentiate the regions. Other groups, however, have divided the bank up differently and so there was a discussion about different ways to divide up regions on the bank. For example, while the broad-scale group has fixed regions, the energy flow investigators have sectors that are time (season) dependent. It was recognized that the broad-scale grid points could be arranged to fit the energy flow sectors if so desired once the data sets are gridded to the broad-scale grid points.

The issue of objective mapping or kriging of data sets came up especially with respect to spatial persistence and correlated length scales. These need to be determined. The question was raised about how to get to a way to do the different data sets to arrive at a consistent answer. This task will be addressed by the broad-scale gridding group.

Adjoint Modeling work – The adjoint modeling work was recognized as particularly useful in comparing the broad-scale distribution data. However, current modeling is solving for R, a combination of biological rate processes and mortality. There is a need for adjoint modeling that brings rate measurements (feeding, growth, reproduction) into the computation so that estimates of predation can be determined. Some of this is already being done by D. McGuillicuddy and X-W Li for Calanus finmarchicus. Other suggestions included:

The adjoint modeling of the larval fish data to look at model predation effects as opposed to field estimated effects, since once a cohort is set in a given year, no more individuals will be created.

The running of the physical/ biological adjoint models in 3D – This was recognized as computationally intensive, a major stumbling block and discussion ensued on how to simplify the problem. The question was raised: “was a possible solution to back away from full model physics?” To some extent, this is being explored by J. Pringle working with C. Chen’s FVCOM model. Also the issue of which model was most appropriate to use in the future adjoint modeling was raised. The need to go from a depth averaged flow field to one with vertical structure was emphasized.

Issue of the use of individuals versus concentrations in the models was raised. Field data on predators, for example, are specified in individual units as opposed to predation impact, which can be specified as a concentration effect. The issue then raised was what are the steps to try to get predation impacts derived from predator abundances into models. This is a task that the predator group is working on.

Synthesis of the data – target species, hydrography, and meteorology - the chronology and its interpretation. A chronology based on the moored array data will be done (shortly?), but what about the other data sets that need to be described using a chronology format? Who is to do it? How will the data/events be presented? How to develop this in such a way that enables the investigators in the program to contribute to the time-line? It may be possible to develop a web based time line that allows individual contributions to be added by the investigators with some of the things in the chronology linked to other related occurrences. It may be necessary to have a number of horizontal time lines that each have hyper-text links that document events.

Some possible fundamental time axes include:.
  • Mooring data of: T, S, ADCP backscatter, currents, MET data on Southern Flank, NE Channel, NE Peak, Crest
  • Broad-scale cruises: Species, and other parameters. Spring bloom timing based on chlorophyll
  • List of broad-scale cruises, moorings, process cruises, satellite images, etc., by time
  • Catalogue of WCR’s

D. Allison demonstrated the various chronologies now online in the GLOBEC database. There are several different approaches that have been taken to organize the events that took place during the GLOBEC years. These range from listings of the cruises and other sampling activities to listings of major physical events. The DMO will undertake to create a Web based interactive system for chronology development.

Issue of Synthesis beyond Georges Bank. This issue was raise in the context of a broader synthesis of data and information between the U.S. GLOBEC and other similar international programs. There was discussion of how to reach out to Northeast Pacific GLOBEC program and the work ongoing in the eastern Atlantic and at the basin-scale. It was clear that this would become important as synthesis progressed and the next Georges Bank AO would likely call for work along these lines.

Issue of flow into GoM via NE channel. Nutrients and other aspects of boundary conditions set by flow in the channel is an essential starting point. The data from the current meters in the Northeast channel need to be taken into consideration. What hardware suites need to be developed for future studies assuming the focus includes chemical and biological variables?

Fluxes of water and bugs through the north flank tidal mixing front. Given the 100 m isobath, what are the flows of water across that boundary as a function of depth? When and where does water actually come on to the Bank in the January to March/April time frame? How are species such as Calanus vertically positioned relative to the flows of water on the Bank? How does this process work in reverse later in the year? What about the nutrient fluxes and how do the water column fluxes of these properties compare? To address some of these questions, the vertical distributions of species at stations 38, 34, 40 and 29 needed to be compared.

It was commented that the shelf break is coincident with the tidal mixing front in some areas and not others. Discussion then centered on the possible mechanisms that affect the flux.

  • Wind forcing (along the front) causing upwelling?
  • Centrifugal upwelling (at specific locations on the front)
  • Instability (jet that may be unstable producing flux across isobaths – all depths)
  • Bottom boundary layer transport (bottom 10 m –along the front)
  • Franks/Chen tidal rectification along the front - mixing in presence of a vertical shear (changes sign – shear dispersion)
  • Freshwater plume in upper 20 m was likened to a hose pointed at Georges Bank in western GoM, but the plume does not show up until May or so.

So are there specific pathways of Calanus onto the Bank and if so why? What is the timing? Annual cycling? What is seasonality of nutrient flux onto the Bank and how does this compare with Calanus flux?

Over-wintering stocks of Calanus in the GoM. What needs to be done next to resolve the issues that have been raised in the literature in the past and current discussions? These include:

  • The need for a factor of two more of Calanus over-wintering in the GoM than was present in the data from the MARMAP years (e.g. Gentleman et al).
  • What is the behavior during dormancy? What controls their vertical distribution? Does Calanus overwinter at a depth where it is not likely to hit the bottom? Does bottom turbulence determine how far down they reside? Issue of buoyancy of the individuals. What controls does the animal have on where it resides? Is there interannual variability in the depth of diapausing individuals?
  • Closing the loop for populations on the Bank. Fluxes of Calanus on and off the Bank i.e. cross-frontal exchange across the tidal mixing front onto the crest and vice versa. How to get the bugs back into the GoM and from where?
  • Exchanges of Calanus from the Scotian Shelf and Northeast Channel into the GoM and via the Northeast Channel out of the gulf. The influence of Scotian Shelf overflows as evidenced in the broad-scale and process data sets. How to determine a direct crossover as opposed to the more circuitous route?
  • Conceptual model of late winter and early spring bloom period. Issue of correlation between haddock recruitment and timing of spring bloom. What needs to be assembled in data sets to address the mechanisms behind the correlation?

Object lessons from the JGOFS Synthesis effort.

D. McGillicuddy led a discussion concerning the synthesis effort and what lessons might be gleaned from JGOFS. He led off by asking “What is synthesis all about?” Synthesis in the two programs does have some differences in approach. For one thing, modeling in JGOFS was largely left until after the field program had ended whereas in GLOBEC the modeling began at the beginning of the program and was continuously funded throughout the field program. This latter method may allow for better integration of results ultimately.

Some lessons learned from JGOFS:
  1. balance between observation based and model based synthesis activities
  2. balance between observationalists and modelers
  3. facilitating interactions by regular SI meetings and smaller targeted workshops
  4. facilitating information exchange via the Data Management Office
  5. identifying critical gaps and getting them written into the next AO
  6. producing synthesis products such as special volumes

Discussion touched on the issue of the openness of the database and availability of the data sets. Although password protection has always been available for use in the time period when the data are considered proprietary, no one has chosen to use it. The need to share manuscripts prior to publication was also discussed. There was a strong desire to see pre-prints posted online at the GLOBEC web site. Issues of copyright need to be taken into consideration and will be investigated by the DMO. A clear message arising from this discussion was that it would be best for the program to maintain flexibility and allow the regional synthesis to continue right up to the end.

Joint Publications- Synthesis Volume(s)

The need for organizing the next synthesis volume was recognized by the group. Among the journals suggested that might produce such a volume are:

Fisheries Oceanography
Journal of Marine Systems
Deep Sea Research II
Journal of Marine Research
Limnology and Oceanography

There was a consensus that Deep Sea Research II ought to be approached since previous GLOBEC special volumes have appeared in that journal. One theme suggested for a synthesis volume is “Understanding population dynamics on Georges Bank: Observational and modeling results”. A list of potential papers in progress or in mind will be assembled and circulated to stimulate the production of the next special issue.

Future Regional Observing

Discussion of an extended observing program on Georges Bank was led by Ken Brink. It was stimulated in part by preparations for the January 2004 Orion meeting in Puerto Rico sponsored by NSF. This focus of the Orion meeting is on observatories, the related scientific rationales and issues, and the infrastructure needed to support observatory science. The meeting is intended to lead to a science plan for ocean observatories.

Based on the discussion, there was a recognition that there ought to be an extended, long-lived observing program on Georges Bank in the wake of, and building on, GLOBEC. Although ORION was the immediate probe for thinking about this, it seemed likely that there are other ways to fund such an ongoing program. We thus had a good deal of discussion on this point.

It appears that, within this group, the main interest is in understanding and predicting biological production and populations (ecosystems, in fact) in this area. A good deal of discussion took place on what ought to be the area of interest, but the consensus appears to be that it makes sense to include the Gulf of Maine, Georges Bank, and the Mid Atlantic Bight as one system connected via alongshore advection. It is not entirely clear what ought to be measured, and where, but it appears that measurements of fluxes into the Gulf of Maine on the Scotian shelf and in the Northeast Channel would make sense. The fluxes should include measurements of nutrients and living things including fish larvae, and the overall project ought to include phytoplankton through fish.

Phase IV SI Meeting in late Spring or early Summer 2004 – During the course of the meeting, there was open discussion of where to have the next Scientific Investigator meeting. Ted Durbin had recently visited the newly built AMC conference center up at Crawford Notch, New Hampshire, which appears to have moderate rates. During the final plenary session, there was a strong recommendation that the project office approach the AMC to see if holding the next Investigator meeting there was feasible. The preference was that the meeting take place sometime between the middle of June and the last part of July. The meeting would run from Monday afternoon to Friday at noon with time off during the week for excursions/hiking etc. There was a strong desire to have a few overview talks to summarize where we are in synthesis and the use of posters and poster sessions to convey other scientific results. Bob Groman will investigate the potential meeting site and communicate with the investigators as to the possible dates.

Technology

The meeting room provided up to thirty high speed Internet connections. On average, there were fifteen laptop computers present daily. A dedicated Window-XP based computer was used to store PowerPoint presentations. Presentation files were copied to this system either via CDrom or via USB-based "memory sticks" or "thumbs." An Epson 720C LCD projector was used to display these talks. In addition, several participants used their own laptop systems (mostly MacIntosh) to present their talks. A laser printer and a color ink jet printer were also available in the meeting room.

Next Year's Science Meeting

On Thurday, we discussed the best dates to hold our next Us GLOBEC Georges Bank Science Meeting. While more people said the the fall would be the better time, a summer date was better for those participants who teach. We decided to look into possible meeting dates in late May and early June. In additonal, T. Durbin suggested that we consider having our next meeting at the Appalachian Mountain Club at Crawford Notch, New Hampshire. Bob G. was asked to look into this. [Editor's Note: The next Investigators' meeting will take place at Salve Regina University, June 21-25, 2004.]

Add Preprints and Published Articles to Web Site

Several attendees suggested that US GLOBEC Georges Bank preprint and published articles be placed on-line, in a similar way as the US JGOFS program has done. Bob G. will follow up. [Editor's note: Bob G. contacted the editor of this US JGOFS web page and was told that every journal has its own set of rules about posting preprints or published articles on the web and one needs to consult with each journal. Usually, the journal will allow the author to maintain a copy of his/her own paper on his/her own web site, but anything beyond that needs permission. Some journals allow preprints to be posted, others do not. It will be necessary to write for special permissions to the journals. But it can it can be done.]