ISSN:
1573-5125
Keywords:
zooplankton
;
grazing
;
chlorophyll
;
phaeopigment
;
particle counter
;
Calanus finmarchicus
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract In grazing experiments, the changes in fluorometric determined concentrations of chlorophyll a and phaeopigment are probably less bothered by the interference of other chlorophyll pigments than in analysis of single seawater samples. Theoretically, phaeopigment recovery will be ca 100%, regardless the eventual presence of chlorophyllb. In shipboard experiments in the northern North Sea in May 1983 the chlorophyll consumption by zooplankton was compared with phaeophorbide egestion. Phaeophorbide recovery amounted on average to 67%, comparable with a previous estimate in laboratory experiments by SHUMAN & LORENZEN (1975). Because phaeophorbide concentrations are expressed in chlorophyll equivalents, one third of the chlorophyll consumed is apparently degraded further than phaeophorbide into non-fluorescent material. In grazing experiments withCalanus finmarchicus stages CIV, CV and CVI ♀ filtering rates were determined both with the chlorophyll method and with a particle counter. Values roughly doubled with stage and averages per stage did not differ systematically between both methods, suggesting that the natural algae food, dominated by the microflagellateCorymbellus aureus, was not preferred above other seston.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF02255092
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