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Biochemical versus mineral limitation in Daphnia
Author(s) -
MüllerNavarra Dörthe C.
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.1995.40.7.1209
Subject(s) - daphnia , scenedesmus , biology , algae , eicosapentaenoic acid , phosphorus , branchiopoda , nutrient , cladocera , food science , botany , fatty acid , ecology , zooplankton , chemistry , biochemistry , polyunsaturated fatty acid , organic chemistry
Laboratory growth experiments were used to test whether observed phosphorus limitation in Daphnia is a direct effect of P availability. Daphnia was fed the algae Cyclotella and Scenedesmus , each P saturated or P limited. The algal species were chosen because of their distinct fatty acid composition, particularly with respect to their eicosapentaenoic acid (20:5 ω 3) content. Although both algal species had reduced 20:5 ω 3 content under P limitation, P‐limited Cyclotella had a substantially higher 20:5 ω 3 content than did P‐saturated Scenedesmus. In keeping with its P and 20:5 ω 3 content, P‐limited Scenedesmus was the lowest quality of food. Inconsistent with mineral P limitation in Daphnia but in agreement with the 20:5 ω 3 content, P‐starved Cyclotella was a better quality of food than was P‐sufficient Scenedesmus. Thus P limitation seems to be a rather indirect effect of changes in algal biochemical composition in response to nutrient stress.