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Photosynthetic rates of phytoplankton in East African alkaline, saline lakes 1
Author(s) -
Melack John M.,
Kilham Peter
Publication year - 1974
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.1974.19.5.0743
Subject(s) - photosynthesis , phytoplankton , environmental science , algae , environmental chemistry , chlorophyll a , hydrology (agriculture) , oceanography , chemistry , botany , biology , ecology , geology , geotechnical engineering , nutrient
Photosynthetic rates were calculated in six myxophycean‐dominated alkaline, saline lakes in Kenya and Tanzania from changes in dissolved O 2 in light and dark bottles and from diurnal variations in dissolved O 2 . Rates of gross photosynthesis are exceptionally high for Lake Nakuru, Kenya, by the diurnal free‐water technique (e.g. 36 g O 2 m −2 day −1 ). Gross photosynthesis in Lake Nakuru was compared for two consecutive days: on the first day pronounced thermal stratification developed and the dissolved O 2 reached 340% saturation in the upper half meter; on the second day wind‐driven turbulence circulated the algae to depths often greater than 2 m in water with Secchi disk visibility of only 15 cm. Because of analytical difficulties in measuring dissolved O 2 in soda lakes, laboratory experiments were conducted to determine the reliability of the titrimetric (Winkler, Miller), gasometric (Scholander), and polarographic (oxygen probe) methods. The polarographic technique was the most suitable for determinations of dissolved O 2 in the field.