Inter-Research |
IR Home
MEPS Home Editors Forthcoming Information Subscribe Journals Home MEPS AME CR DAO ESEP ESR Search Subscribe Book Series EE Books Top Books ESEP Books Order EEIU Brochures (pdf format) Discussion Forums Home Research IR Research Institutions International Ecology Institute Eco-Ethics International Union Foundation Otto Kinne Foundation |
Role of lipids in the maintenance of neutral buoyancy by zooplanktonR. W. Campbell*, J. F. DowerSchool of Earth & Ocean Sciences, University of Victoria, PO Box 3055 Stn CSC, Victoria, British Columbia V8W 3P6, Canada
ABSTRACT: Many types of zooplankton contain large proportions of lipids. Usually, these lipids represent energy storage compounds, but it has also been suggested that lipids play a role in buoyancy regulation. Lipids are thought to determine the
overwintering depth of large calanoid copepods, and it has been widely assumed that these organisms overwinter at some 'depth of neutral buoyancy'. However, lipids are generally more compressible, and have a larger thermal expansion than seawater. This
means that any depth of neutral buoyancy will be inherently unstable. Model results show that the ascent rates attributable to this instability are small at depth (where temperature changes are small), suggesting a simple way for animals to remain at
depth while overwintering. However, model results also show that the buoyant properties of a copepod (or any small plankter) are extremely sensitive to its relative biochemical composition. This presents problems to maintaining vertical position, but may
also be useful for vertical migrations.
KEY WORDS: Copepod · Zooplankton · Lipid · Buoyancy · Model · Depth distribution · Vertical migration
Published in MEPS Vol.
263
(2003) on November 28
|
Copyright © 2004; Inter-Research
Webmaster: webmaster@int-res.com |