Kenneth H. Coale; Moss Landing Marine Laboratories and San Jose State University Foundation

"Iron in Antarctic Polar Front Zones"

The central hypothesis of our work is that the concentration of iron, together with other factors, regulates the structure and function of Southern Ocean ecosystems. Our focus will be to determine the vertical (0250 m) and horizontal variability of the distribution of iron, and other trace metals, as part of the Ross Sea Process cruises. We will perform a series of deckboard enrichment experiments in order to assess the threshold of phytoplankton limitation for iron and zinc. Each experiment will be monitored for changes in metals, nutrients, chlorophyll, species composition, POC, PON and DOC. We wish to determine if the Michaelis Menten relationship between community growth and iron concentration derived for equatorial Pacific populations (half saturation constant = 0.12 nM, and saturating concentration = 1 nM), apply to Southern Ocean waters where dissolve iron is also <0.1 nM. In addition, the analysis of lithogenic elements such as Al will enable us to assess the significance of terrigenous inputs for these metals. Subsamples of TM clean enrichment waters may be available to other participants.