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Effects of temperature and current discharge on the concentration and photosynthetic activity of the phytoplankton in the upper Mississippi River
Author(s) -
BAKER ALAN L.,
BAKER KATHLEEN KROMER
Publication year - 1979
Publication title -
freshwater biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.297
H-Index - 156
eISSN - 1365-2427
pISSN - 0046-5070
DOI - 10.1111/j.1365-2427.1979.tb01502.x
Subject(s) - phytoplankton , photosynthesis , chlorophyll a , environmental science , chlorophyll , zoology , current (fluid) , spring (device) , hydrology (agriculture) , atmospheric sciences , botany , biology , ecology , oceanography , nutrient , geology , physics , geotechnical engineering , thermodynamics
SUMMARY. Temperature and current discharge regulated phytoplanktonic concentration, chlorophyll‐a concentration, the light‐saturated rate of photosynthesis (P max ), and photosynthetic capacity (P cap ) in the Mississippi River at Prairie Island, Minnesota. The chlorophyll‐a maximum was 48 mg m −3 in 1975, a wet year with a high current discharge, and 190 mg m −3 in 1976, a relatively dry year. The highest values of P max were 0.37 (mgO 2 I −1 h −1 ) in 1975 and 1.60 in 1976. P cap varied from 3 to 21 (gO 2 per g chlorophyll‐a h −1 ) both years, and its value was highly correlated with temperature. The temperature optimum shifted from 16°C for P cap in the spring, to greater than 28°C in the summer. Multiple regression analysis indicated a second‐order relationship of P cap in the spring to temperature. Other independent variables explained only negligible variation of P cap .