Developing a carbon-budget trophic model of the Ross Sea, Antarctica: work in progress

We report on the development of a carbon-budget trophic-model of the Ross Sea. We provisionally defined the food web of the Ross Sea as having the following functional compartments: birds, seals, toothed whales, baleen whales, large bentho-pelagic predatory fish (mainly adult Antarctic toothfish), pelagic and juvenile fish (mainly Antarctic silverfish), demersal fish (skates, rattails, notothenioids), cryopelagic fish, squid, macrozooplankton (including krill and salps), macrobenthos, meiobenthos, ice heterotrophs, water column zooplankton (ciliates, heterotrophic flagellates, mesozooplankton), three groups of bacteria (water column, ice, and sediment), phytoplankton, epontic algae, and three detritus groups (water column, ice, and benthic). The simple trophic model requires well over a hundred parameters, each of which has been estimated by sifting published and unpublished information. Local information on organisms in the Ross Sea was used whenever available. Where no information in the literature was available we have sought out field measurements that have not been published, or estimated values using explicit assumptions.
The model is not complete, and should be considered a work in progress. A trial budget was created to quantify carbon flow through our conceptual model of the Ross Sea ecosystem. A first run of the model was carried out, and the initial set of parameters was not found to be self-consistent i.e. they do not lead to a balanced model. The next step is to determine the range of ecosystem variables that are consistent with our current understanding of the constraints on ecosystem functioning within the bounds of uncertainty estimated for each parameter; we term this approach feasible parameter space mapping.