Linkages between iron supply and primary production in the Southern California Current System

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Iron supply has been shown to be a fundamental control on the productivity of Eastern Boundary upwelling regimes, such as the coastal California Current region. Utilization of upwelled nitrate, phosphate and silicate and the generation of large phytoplankton blooms is dependent on the supply of iron from shelf sediments during the upwelling season. Farther offshore, in lower-nutrient waters with more diffuse upwelling, the supply of iron relative to macronutrients is also an important factor in structuring the ambient planktonic community. This poster will summarize recent investigations of iron supply, iron limitation, and iron and macronutrient biogeochemistry in waters of the southern California Current System, extending from the Point Conception upwelling center south to San Diego, and 500 km offshore. This area is the focus of the long-running California Cooperative Oceanic Fisheries Investigations time series, as well as the California Current Ecosystem Long Term Ecological Research site (CCE LTER). Results indicate that iron is a meaningful parameter in the context of these important long-term, large-scale research programs which seek to understand interactions between net primary production and climate variability in ocean upwelling systems.