Mass density contrast in relation to the feeding currents in calanoid copepods Academic Article uri icon

abstract

  • Theoretical analyses show that positively buoyant copepods are able to generate feeding currents by adopting upside-down body positions and pushing water upward. Thus, the excess buoyancy acting on the copepods will be balanced and cone-shaped feeding currents generated to transport water to the capture areas. The intensities of the feeding currents, which can be measured in the present modeling study by calculating the volumetric flux going through the capture areas, are proportional to the mass density contrasts between the copepods and the ambient seawater. The mass density contrasts may vary spatially and temporally depending on copepod body contents and on the properties of the seawater immediately surrounding them. We focus on the case where the mass density contrast between a wax ester-rich copepod and its ambient seawater can vary strongly with depth because wax esters are more compressible and 6-10 times more thermally expansible than seawater. These theoretical analyses show that the intensities of the feeding currents generated by wax ester-rich copepods vary strongly with depth. Our conclusions from these theoretical analyses need to be tested by direct observations.

publication date

  • October 1, 2005