Modelling the Effects of Eddies and Mean Flows on Southern Ocean Biology

Massachusetts Institute Of Technology, Cambridge MA

Investigators

Abstract

This project is an attempt to understand the interactions of biological and physical dynamics by modeling the spatial distribution of antarctic krill, a small crustacean that forms dense aggregations or patches on the small scale. The spatial distribution of these patches appear to depend on the advance and retreat of the sea ice, the three dimensional movement of water masses from small scale turbulence to the dynamics of the Antarctic Circumpolar Current, as well as on food supply and predation pressure. Prior work has shown that physical processes dominate on the larger scale, while biological processes dominate on the smaller scale, but the relative importance of the two as a function of scale has not been investigated systemically. This work will be carried out in the context of the Southern Ocean Experiment of the Global Ocean Ecosystem Dynamics Study (Globec), a large, multi-investigator study of the winter survival strategy of krill under the antarctic sea ice. The problem of accurately representing patchiness in a circum-antarctic model is that of properly representing effects that occur on a scale that is not resolved in the model. The approach that will be used here is to first study a detailed model that can resolve the scale of krill patches and can help to analyze and understand the observations that will be made in the Experiment. These results will allow us not only to make a more quantitative estimation of the errors involved, but also to improve the parameterization of krill distributions in meso-scale and basin-scale models of the Southern Ocean. ***