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Differential effects of iron additions on organic and inorganic carbon production byphytoplankton
Author(s) -
Lam Phoebe J.,
Tortell Philippe D.,
Morel François M. M.
Publication year - 2001
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.2001.46.5.1199
Subject(s) - subarctic climate , iron fertilization , total organic carbon , carbon fibers , autotroph , new production , environmental chemistry , phytoplankton , total inorganic carbon , oceanography , biomass (ecology) , nutrient , environmental science , chemistry , ecology , biology , geology , carbon dioxide , materials science , genetics , composite number , bacteria , composite material
Bottle and mesoscale experiments have demonstrated that iron additions enhance phytoplankton growth and reduce surface pCO 2 in highߚnutrient, low‐chlorophyll (HNLC) regions of the world oceans. Here we show that iron additions specifically stimulate organic but not inorganic carbon production in the HNLC Subarctic Pacific. Fiveߚhour 14 C labeling experiments performed during incubation of surface water samples demonstrated a large increase in the rate of organic carbon produced but no change in the rate of inorganic carbon production. The same result was obtained on two different dates: one when coccolithophores formed a relatively large proportion of total autotrophic biomass; the other when coccolithophores were less abundant. Together with previous taxonomic observations, our results imply that iron fertilization may be particularly effective in drawing down CO 2 in surface waters by stimulating primary production but not calcium carbonate precipitation, which augments CO 2 .