Aquatic Sciences Meeting, Albuquerque 2001

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

Date: Thursday, February 15, 2001, Time: 10:00:00 AM

Location: Mesilla

Campbell, R, W, Dept. Of Earth and Ocean Sciences, University of British Columbia, Vancouver, Canada, campbell@eos.ubc.ca

Dower, J, F, Dept. Of Earth and Ocean Sciences, University of British Columbia, Vancouver, Canada, dower@eos.ubc.ca

AN EQUATION OF STATE FOR A COPEPOD: THE DEPTH DISTRIBUTION OF OVERWINTERING NEOCALANUS PLUMCHRUS IN THE STRAIT OF GEORGIA, BRITISH COLUMBIA, CANADA.

High-latitude pelagic ecosystems are often dominated by large calanoid copepods that overwinter at depth in a quiescent state. The depth range of such overwintering copepods tends to be quite narrow, but it is unknown by what mechanisms the observed vertical distributions are created and maintained. Since they do not swim, it has been proposed that overwintering copepods settle to their depth of neutral buoyancy, which is determined partially by their species-specific lipid contents. However, copepod lipids (usually wax ester) are more compressible than seawater. Thus, the depth of neutral buoyancy for a given species is not stable: if displaced up (or down) from that depth, the copepod should continue ascending (or sinking). We will present depth-stratified measurements of lipid composition, water content, and the structural mass of Neocalanus plumchrus, the dominant copepod from the Strait of Georgia, Canada. The distribution of these constituents, as well as their relative importance in determining the copepod density will presented in the framework of an equation of state for Neocalanus plumchrus, thereby illustrating the relative importance of body composition and buoyancy in determining its overwintering depth distribution.

This Session Listing

Aquatic Sciences Meeting, Albuquerque 2001

Quicklinks