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Taxon‐specific analysis of microzooplankton grazing rates and phytoplankton growth rates
Author(s) -
Waterhouse Tye Y.,
Welschmeyer Nicholas A.
Publication year - 1995
Publication title -
limnology and oceanography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.7
H-Index - 197
eISSN - 1939-5590
pISSN - 0024-3590
DOI - 10.4319/lo.1995.40.4.0827
Subject(s) - grazing , phaeodactylum tricornutum , emiliania huxleyi , isochrysis galbana , phytoplankton , clearance rate , biology , algae , bloom , zoology , ecology , nutrient , endocrinology
We performed laboratory experiments to test the accuracy of using HPLC to estimate taxon‐specific grazing and growth rates obtained by the dilution technique. In seven of nine experiments, this technique underestimated microzooplankton grazing rates. The average estimated grazing rates were 52% of the true grazing rates for chlorophyll a and 33% for taxon‐specific pigments. With the food sources Phaeodactylum tricornutum, Isochrysis galbana, Gymnodinium sp., and Emiliania huxleyi, the clearance rates for Oxyrrhis marina were between 2 × 10 −3 and 7 × 10 −3 ml grazer −1 d −1 , at initial food concentrations of ∼5 × 10 3 cells ml − 1 . At higher food concentrations (1 × 10 5 cells ml −1 ) clearance rates decreased to ∼ 1 × 10 −4 ml grazer −1 d −1 . In field experiments performed in September 1991 and March 1992 in Monterey Bay, California, 21–55% of the phytoplankton standing stock was consumed daily by microzooplankton grazing. The underestimation of grazing rates in the laboratory experiments implies that rates obtained in field incubations may be in error.