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Assimilation of silicic acid by phytoplankton in the Baja California and northwest Africa upwelling systems 1
Author(s) -
Nelson David M.,
Goering John J.
Publication year - 1978
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.1978.23.3.0508
Subject(s) - upwelling , silicic acid , diatom , oceanography , phytoplankton , nutrient , geology , silicic , environmental science , algae , biogenic silica , environmental chemistry , geochemistry , ecology , chemistry , biology , volcano
Rates of silicic acid uptake by natural phytoplankton populations were measured at 31 stations in the region of coastal upwelling off Baja California, and 28 in the upwelling region off northwest Africa, using the stable isotope 30 Si. Silicic acid uptake in both systems extended to about twice the depth to which carbon and nitrogen assimilation was observed, and continued at substantial rates throughout the 24‐h day. Kinetic experiments, performed at the two Baja California stations and four northwest Africa stations exhibiting the lowest near‐surface silicic acid concentrations observed, did not show the rate of uptake to be substrate limited. Data on upwelling velocities, nutrient concentrations, and nutrient uptake rates suggest that silicon limitation in the Baja California system was prevented by high rates of silicic acid regeneration resulting from dissolution of diatom silica.