Aquatic Sciences Meeting, Albuquerque 2001

SS15 Biomechanics: Making the Connection Between Physics and Biology at the Organismal Level (Disciplinary Connections)

Date: Wednesday, February 14, 2001, Time: 4:00:00 PM

Location: Mesilla

Kiorboe, T, , Danish Institute for Fisheries Research, Charlottenlund, Denmark, tk@dfu.min.dk

Jackson, G, A, Texas A&M University, College Station, USA, gjackson@tamu.edu

MARINE SNOW, ORGANIC SOLUTE PLUMES, AND OPTIMAL CHEMOSENSORY BEHAVIOUR OF BACTERIA

Leaking organic solutes form an elongated plume in the wake of a sinking aggregate. These solutes may both be utilized by suspended bacteria and guide bacteria with chemokinetic swimming behavior towards the aggregate. We used modifications of previously published models of the flow and concentration fields around sinking aggregates and of chemokinetic behavior of bacteria to identify the behavior that optimizes aggregate colonization and plume utilization. The optimum solution is governed by physical constraints and is a trade-off between a high sensitivity to chemical signals and a long signal integration time. For a run and tumble swimming behavior the predicted tumbling frequency is between 1-10 s^-1, similar to that reported for marine bacteria. The predicted optimum sensitivity to chemical signals is higher than that known for E. coli. The optimum behavior was then used to examine the potential contribution of aggregate-generated solute plumes for water column bacterial production. Despite occupying only a small volume fraction, the plumes may account for a significant proportion of water column bacterial production at typical concentrations of marine snow aggregates.

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Aquatic Sciences Meeting, Albuquerque 2001

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