Abstract

Evidence exists for decadal-scale variations in chlorophyll, primary production and/or zooplankton biomass in many regions of the oceans. In general, however, we lack sufficient understanding of trophic structure and food-web fluxes to evaluate differences within and among systems or to serve as baselines for documenting and predicting effects of future climate changes. For the eastern equatorial Pacific, a large and globally significant player in ocean-atmosphere carbon cycling, rigorous results of experimental process studies have been combined with simple modeling to examine some of the details of plankton trophic pathways. The results provide well-constrained estimates that partition production and fates of major phytoplankton taxa, the depth distributions of growth and loss processes within the euphotic zone, the roles of micro- and mesozooplankton in carbon and silica cycling, the contributions of various food-web components to respiration and DOC cycling, and the growth efficiencies, dietary inputs and secondary production of planktonic consumers. Detailed field-based process studies complement the temporally and spatially expansive observations that can be done remotely, for example by satellites or drifter arrays, and provide the basic data needed to develop and parameterize models that can link long-term ecosystem responses to trends in physical forcing.

Institute for Advanced Study
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