Global Change and Marine Ecosystems
Evidence continues to accumulate that the environment of our planet is
changing (e.g., Mitchell, 1989). Many of the changes are thought to be
the consequences of human intervention into natural processes (such as
the ozone depletion over the Antarctic, increased concentrations of
greenhouse gases, the enhanced acidity of rainfall downwind of
industrialized areas, etc.), but paleoclimatic records reveal that the
earth has experienced at least some similar changes in the past. We
possess little knowledge of the spatial or temporal scales of these
changes. Some occur on relatively short time scales (El Nino-Southern
Oscillation Events), whereas others may be operating over very long
periods of time (the incorporation of carbon into the deep sea: Broecker
and Peng, 1982). Even for processes that operate at a global scale, the
climatic shifts are not uniformly distributed across the face of the
globe. This characteristic not only complicates detection but also
demands mechanistic models to permit prediction of future change. Many
scientists are now deeply involved in verifying the existence and
magnitude of these shifts in the environment, as well as in modeling the
likelihood of various alternative scenarios for future change. These
studies of the shifts in the physical and geochemical environment of our
planet are of critical importance, but equally urgent is the challenge
of assessing the biological consequences and the sustainability of
biological life-support systems in the face of such global change.
GLOBEC (GLOBal ocean ECosystems dynamics) is a research initiative
proposed by the oceanographic and fisheries communities to address the
question of how changes in global environment are expected to affect the
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 abundance of key marine animal populations and their
variances in space and time. We assume that the physical environment is
a major contributor to pattems 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 the 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.
