Southern Ocean Iron Enrichment Experiment: Carbon Cycling in High- and Low-Si Waters

• DOI: 10.1126/science.1089778
• Publication Date: 2004-04-15T20:43:25Z
• Authors: Kenneth H. Coale; Kenneth S. Johnson; Francisco P. Chavez; Ken O. Buesseler; Richard T. Barber; Mark A. Brzezinski; William P. Cochlan; Frank J. Millero; Paul G. Falkowski; James E. Bauer; Rik H. Wanninkhof; Raphael M. Kudela; Mark A. Altabet; Burke E. Hales; Taro Takahashi; Michael R. Landry; Robert R. Bidigare; Xiujun Wang; Zanna Chase; Pete G. Strutton; Gernot E. Friederich; Maxim Y. Gorbunov; Veronica P. Lance; Anna K. Hilting; Michael R. Hiscock; Mark Demarest; William T. Hiscock; Kevin F. Sullivan; Sara J. Tanner; R. Mike Gordon; Craig N. Hunter; Virginia A. Elrod; Steve E. Fitzwater; Janice L. Jones; Sasha Tozzi; Michal Koblizek; Alice E. Roberts; Julian Herndon; Jodi Brewster; Nicolas Ladizinsky; Geoffrey Smith; David Cooper; David Timothy; Susan L. Brown; Karen E. Selph; Cecelia C. Sheridan; Benjamin S. Twining; Zackary I. Johnson
• Keywords: Chlorophyll; Diatoms; 0106 biological sciences; Nitrates; Atmosphere; Nitrogen; Chlorophyll A; Iron; Oceans and Seas; Silicic Acid; Carbon Dioxide; 01 natural sciences; Carbon; 13. Climate action; Phytoplankton; Seawater; 14. Life underwater; Biomass; Photosynthesis; Ecosystem; 0105 earth and related environmental sciences

The availability of iron is known to exert a controlling influence on biological productivity in surface waters over large areas of the ocean and may have been an important factor in the variation of the concentration of atmospheric carbon dioxide over glacial cycles. The effect of iron in the Southern Ocean is particularly important because of its large area and abundant nitrate, yet iron-enhanced growth of phytoplankton may be differentially expressed between waters with high silicic acid in the south and low silicic acid in the north, where diatom growth may be limited by both silicic acid and iron. Two mesoscale experiments, designed to investigate the effects of iron enrichment in regions with high and low concentrations of silicic acid, were performed in the Southern Ocean. These experiments demonstrate iron's pivotal role in controlling carbon uptake and regulating atmospheric partial pressure of carbon dioxide.