OO - Introduction and Background

## Introduction and Background

### U.S. GLOBEC Objectives

The overall objective of the U.S. Global Ocean Ecosystem Dynamics (U.S. GLOBEC) Program is to understand the physical and biological processes that control the population dynamics of key populations of marine animals in space and time.

### Importance of Open Ocean Ecosystems

U.S. GLOBEC efforts to date are focused on areas, like Georges Bank and the Arabian Sea, that are of a relatively limited spatial extent and are subject to strong, seasonal climatic forces which are likely to affect or control the dynamics of animal populations. Tropical and subtropical open ocean ("blue-water") environments are, in contrast, among the largest definable ecosystems on the planet. Moreover, they exist in less seasonally variable regimes, and may be controlled by the interplay of physical and biological forces on much different time and space scales than the ocean margins. The study of these systems may provide a valuable comparison to the more physically forced sites that U.S. GLOBEC will study, and could illustrate different kinds of physical-biological interactions.

### Workshop Goals

The purpose of the workshop was to explore and identify some issues or situations concerning population dynamics of zooplankton or fish in the open ocean that could be the basis of comparison with regions that are physically and climatically dynamic. The primary goal was an intellectual one, to stimulate thought and discussion about problems in population ecology of oceanic animals, but it was also expected that specific questions for investigation within the GLOBEC (and perhaps JGOFS) frameworks would be identified.

Despite the fact that they cover much of the globe, the remote and dilute nature of blue-water environments has made them difficult places to study. Good time-series data on abundance, growth and distribution of populations will be difficult and expensive to collect in such regions. Thus, there was particular interest in including discussions of new biochemical and molecular techniques that might be applied to the assessment of biological constraints, such as genetics, feeding history, physiological condition, or growth rates, on the population dynamics of blue-water organisms. These approaches could be particularly valuable in open ocean environments where the logistics and resources for long-term sampling efforts are not likely to be available. To facilitate the transfer of new technologies to open ocean problems, the workshop sought to bring together a mixture of investigators, some with experience in blue-water environments and an appreciation for the special characteristics of the organisms that live there, and others involved in the development of new analytical or diagnostic methods. The emphasis was on individual-investigator scale problems and opportunities for collaborative research within the logistical umbrellas of existing or scheduled programs (e.g., JGOFS HOTS and BATS sites), rather than a new large program.

### Workshop Structure

The three day workshop was held at the Woods Hole Oceanographic Institution from 13 to 15 September, 1993. Each of the 22 invited participants (Appendix 3) was asked to prepare a one-page summary of his/her research interests and perspectives in advance of the meeting. The first day was devoted to a series of half-hour presentations/discussions on topics of relevance to the whole group:

Community structure in the Central Pacific Gyre | J. McGowan
Tropical zooplankton populations | R. LeBorgne
Zooplankton community dynamics in the North Atlantic | E. Head
Research at HOTS and BATS sites | M. Landry & T. Michaels
Feeding biology of oceanic copepods | G. Paffenhöfer
Ecology of leptocephali in the open ocean | M. Miller
Population genetics of pelagic fishes | P. Graves
Molecular population genetics of zooplankton | A. Bucklin
Population regulation: physical and biological factors | H. Caswell
Cell proliferation and growth rate | M. Moore

The second day was devoted to working group discussions on four broad topics, with the participants divided for concurrent morning sessions and remixed for afternoon sessions (Appendix 2):

A. Population characteristics and genetics | A.M.
B. Distributional patterns and sampling problems | A.M.
C. Biological processes and rates | P.M.
D. Physical and biological forcing | P.M.

Working group progress reports and report writing were scheduled for the third day, and the meeting ended with a plenary session for discussing the working group summaries.