AGGREGATION IN THE MARINE-ENVIRONMENT

The spatial distribution of chemical elements in the ocean is controll ed by particles (including organisms); aggregation controls the partic le properties. Coagulation is an important mechanism for controlling t he size of marine particles and thereby their transport properties. Co agulation theory has provided a framework for the calculation of aggre gation rates and size distributions. The use of fractal scaling to rel ate aggregate length to mass has been an important development that st ill needs to be fully incorporated into mathematical expressions for p article collision rates. In addition, disaggregation has emerged as an important process that is poorly described mathematically. Observatio ns of particle spectra in the ocean are in general agreement with thos e expected for coagulation processes but tend to be for too small a si ze range to include the effects of particle disaggregation. Analysis o f material caught in sediment traps suggests that aggregates are the d ominant form of material falling through the ocean. An important aspec t of the marine system is the presence of multiple particle sources th at can confound fractal scaling based on single source particles. Coup led coagulation and chemical reaction models have become important too ls in the interpretation of Th distributions. Further development of c oagulation theory to describe marine systems promises to push the limi ts of our understanding of coagulation processes and their implication s.