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Silicic acid uptake and incorporation by natural marine phytoplankton populations 1
Author(s) -
Azam F.,
Chisholm S. W.
Publication year - 1976
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.1976.21.3.0427
Subject(s) - silicic acid , phytoplankton , carbon fixation , saturation (graph theory) , irradiance , photosynthesis , carbon dioxide , kinetics , tracer , environmental chemistry , seawater , silicic , botany , oceanography , chemistry , environmental science , biology , geology , ecology , physics , optics , paleontology , nutrient , volcano , mathematics , combinatorics , quantum mechanics , nuclear physics
68 Ge‐germanic acid was used as a tracer to study the uptake and incorporation of silicic acid by natural phytoplankton populations in the Gulf of California. The technique was useful in measuring silicic acid incorporation rates as low as 0.5 nM h ‒1 . The incorporation followed saturation kinetics. K s values at two stations were 1.59 and 2.53 µ M. The incorporation was light dependent, maximum rates being achieved at 0.28 × 10 21 photons cm ‒2 d ‒1 (0.044 ly min ‒1 ; 9% of surface irradiance) and half‐maximum rate at 0.02 × 10 21 photons cm ‒2 d ‒1 (0.003 ly min ‒1 ; 0.6% of surface irradiance); rate of incorporation in the dark was 44% of that at light saturation. Enrichment with silicic acid caused stimulation of photosynthetic carbon fixation at two stations.