Coupling of Trace Metal Micronutrients and Phytoplankton Dynamics - A Focus on the Bering Sea and the Role of Iron

University Of California-Santa Cruz, Santa Cruz CA

Investigators

Abstract

ABSTRACT OCE-0137085 An exciting research frontier in ocean sciences involves the role of micronutrient trace metals such as Fe, Mn, Zn, and Co in affecting the structure and function of plankton communities. Certain bioactive trace metals - in particular iron - can influence marine phytoplankton at the molecular, cellular, community and ecosystem levels. Of particular importance is the critical role trace metals such as iron play as biolimiting micronutrients, especially in areas where macronutrients are provided to the surface waters by upwelling or vertical mixing at high rates. The focus of this project is a major month-long field effort to the Bering Sea in July 2003 to investigate the role of micronutrient trace metals (with a focus on Fe) in influencing phytoplankton communities. Researchers at the University of California at Santa Cruz will study the major high-nutrient, low-chlorophyll regions of the oceanic Bering Sea gyre and the western subarctic gyre - regions that they believe are Fe-limited. They will also examine the Bering Sea Shelf - a productive region that covers almost half of the Bering Sea. This is an extremely wide continental shelf, ranging from 500 to over 800 km in width. There has been mention of an "iron curtain" occurring over the inner shelf of the Bering Sea, although there are no data available to confirm this idea. There is a "Green Belt" of high chlorophyll and primary production that occurs throughout the summer at the shelf break which must receive adequate Fe along with macro-nutrients to sustain itself. An emphasis of this study will be to examine the distribution of Fe (and other micronutrient trace metals) relative to the macronutrient distributions in order to gain insight into the relative supply and demand of micro- and macronutrient elements in the various regions of the Bering Sea. In addition to the major field effort in the Bering Sea, these researchers will conduct a study to address the role of iron in influencing phytoplankton communities in the central California upwelling system.