Meeting Abstract

8.6  Sunday, Jan. 4  Filter feeders and plankton increase particle encounter rates through flow regime control HUMPHRIES, S; University of Sheffield, UK s.humphries@sheffield.ac.uk

Collisions between particles or between particles and other objects are fundamental to many processes that we take for granted. They drive the functioning of aquatic ecosystems, the onset of rain and snow precipitation, and the manufacture of pharmaceuticals, powders and crystals. Here I show that the traditional assumption that viscosity dominates these situations leads to consistent and large-scale underestimation of encounter rates between particles and of deposition rates on surfaces. The new theory provides a good match to empirical data and has great implications for our understanding of selection pressure on the physiology and ecology of organisms; for example filter feeders that are able to gather food at much greater rates than previously estimated. I provide evidence that filter-feeders have been strongly selected to take advantage of this flow regime and show that the predicted dynamics of plankton blooms are dramatically changed with the incorporation of the new theory.