Initial Science Plan - Abstract

## Abstract

GLOBEC (GLOBal ocean ECosystems dynamics) is a research initiative organized by the oceanographic and fisheries communities as a component of the U.S. Global Change Research Program to address the question of how changes in global environment are expected to affect abundances, variations in abundance, and production of animals in the sea. Our approach to this problem is to develop a fundamental understanding of the mechanisms that determine both the abundances of key marine animal populations and their variances in space and time. We assume that the physical environment is a major contributor to patterns of abundance and production of marine animals, in large part because the planktonic life stages typical of most marine animals are intrinsically at the mercy of fluid motions of the medium in which they live. Consequently, we reason that a logical approach to predicting the potential impact of a globally changing environment is to understand how the physical environment, both directly and indirectly, contributes to animal abundance and its variability in marine ecosystems.

GLOBEC's approach to this problem has several definable characteristics:

- A partnership between physical and biological oceanographers will be needed to assess how population and ecosystem dynamics are linked to physical phenomena in the sea, from the large scale, such as changing inputs of freshwater modifying buoyancy-driven flows in the entire Gulf of Alaska, for example, to the smaller scales of turbulence, mixing, and transport near-shore and in fronts.

- GLOBEC's population and ecosystem dynamics approach will require evaluation and integration of the fundamental biological rates of feeding, survivorship, and reproduction. These, in turn, will depend upon passive and active movements of individuals, effects of predators, competitors, and commensals, key aspects of the physical environment, food quality and quantity, and how physics modify biological interactions.

- GLOBEC's intent is to construct general physical/biological models of ecosystems dynamics based upon "first-principle" mechanisms of processes that affect the individual organisms. By understanding mechanism we may extrapolate, generalize, and predict from site-specific results.

- Study sites for GLOBEC field programs are proposed for (1) the Northwest Atlantic, including Georges Bank, as a contribution to the international Cod and Climate Change Program, (2) the California Current ecosystem, as representative of an Eastern Boundary Current upwelling system, (3) the Antarctic, to investigate a high-latitude system, where models of climate predict some of the greatest climate changes, (4) an open ocean site in the Indian Ocean, where effects of climate-driven variation in monsoon events can be assessed, and possibly (5) an Alaska Current system, where changes in buoyancy-driven coastal flows could be evaluated.

- The mechanistic understanding of the processes that determine abundance, fluctuation in abundance, and production of marine animals must necessarily involve coupled physical-biological models, linking performance of the individual organism to local and mesoscale physical processes and linking both the biology and local and regional physics to basin-scale changes in global climate. Modeling will play a substantial role in GLOBEC.

- An optimistic prognosis for the success of GLOBEC is based in large measure on the potential for novelty and fundamental scientific breakthroughs that can come from integrating the physical and biological processes. The development of new technologies that will allow coverage of biological sampling to approach that now possible in ocean physics promises giant steps forward in appreciating the role of changing physics and global climate in modifying marine ecosystems dynamics.