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In situ depletion of phytoplankton by an azooxanthellate soft coral
Author(s) -
Fabricius Katharina,
Yahel Gitai,
Genin Amatzia
Publication year - 1998
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.1998.43.2.0354
Subject(s) - phytoplankton , coral , chlorophyll a , algae , reef , coral reef , oceanography , environmental science , biology , in situ , nutrient , ecology , chemistry , botany , geology , organic chemistry
The in situ removal of phytoplankton by the soft coral Dendronephthya hemprichi was investigated by taking small‐scale measurements of chlorophyll concentrations around colonies on a reef of the northern Red Sea. The chlorophyll concentration downstream of a 0.75‐m‐deep colony thicket was depleted by 6.4% (± 1.4% SE) compared with the water upstream. Neighboring organisms are thus exposed to water that is significantly depleted of phytoplankton. A 0.75 × 0.1 × 0.1‐m passage of actively feeding colonies removed 34 mg of carbon per day from the water, equivalent to ~1.3 times their respiratory carbon demand. Rates of algae intake were also estimated by determining the decrease in gut fluorescence in starved colonies. The in situ depletion technique showed a three‐ to sixfold greater sensitivity compared with the gut fluorescence technique, and should be preferred as a technique for estimating feeding rates.