Woods Hole Oceanographic Institution

Dr Phoebe J Lam

»Inverse methods for particle dynamics
»The speciation of marine particulate iron
»The dynamic biological pump
»The continental margin is a key source of iron
»High Biomass Low Export regimes in the Southern Ocean
»Wintertime phytoplankton bloom in the Subarctic Pacific supported by continental margin iron
»Differential effects of iron additions on organic and inorganic carbon production by phytoplankton

Phoebe J. Lam, Philippe D. Tortell, Francois M.M. Morel, Differential effects of iron additions on organic and inorganic carbon production by phytoplankton, Limnology and Oceanography, 46(5): 1199-1202, 2001

Bottle and mesoscale experiments have demonstrated that iron additions enhance phytoplankton growth and reduce surface pCO2 in high-nutrient, 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. Five-hour 14C 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 obser vations, our results imply that iron fertilization may be particularly effective in drawing down CO2 in surface waters by stimulating primar y production but not calcium carbonate precipitation, which augments CO.

FILE » Lam et al. 2001 L&O

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