INVERSE MODEL ANALYSIS OF THE PLANKTONIC FOOD-WEB OF TAKAPOTO ATOLL (FRENCH-POLYNESIA)

A steady-state model of the planktonic food web of the lagoon of Takap oto Atoll (Tuamotu Archipelago, French Polynesia) was developed to ass ess the characteristics of that ecosystem. The planktonic food web was divided into 7 compartments, whose carbon biomasses and rates of exch ange were determined from field data combined with inverse analysis, t he latter being used to estimate missing rates. Results indicate that the system was characterized by high phytoplankton production and, in agreement with previous results, low bacterial production. Due to thei r high metabolism, metazoan zooplankton played a dominant role in the cycling of carbon. In contrast, the contribution of protozoa was small . The non-living particulate organic carbon compartment also played a key role, qualitatively and quantitatively, because detritus was direc tly consumed by all heterotrophic compartments.