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.
