Doney¹, Scott C., Keith Moore² and Keith Lindsay³

¹Woods Hole Oceanographic Institution, E-mail: sdoney@whoi.edu, ²U.C. Irvine and ³NCAR

The role of iron and community structure in a global ocean ecosystem and carbon cycle model

Over the last decade, JGOFS and related field studies have dramatically altered our basic conceptualization of ocean biogeochemistry, highlighting the importance of (among other things) trace-metal limitation, community structure, and planktonic “geochemical functional groups” (e.g., diatoms, nitrogen fixers, calcifiers). These plankton groups provide important links between ocean carbon and the biogeochemical cycles of other key species (e.g., macro- and micro-nutrients, alkalinity, silica). To better quantify the role of marine ecosystem dynamics on the global ocean carbon cycle, we have developed a new global, three-dimensional coupled ecobiogeochemistry model under the framework of the CCSM-Ocean model. Community structure is determined prognostically by a balance of temperature, light, and multi-nutrient limitation (Fe, P, N, Si) as well as zooplankton grazing. The ecological components are linked with full carbonate system chemistry and an iron biogeochemical cycle. We will present results from global simulations, focusing on model-data evaluation against standard metrics (local time-series stations; SeaWiFS ocean color and primary productivity; export production; and air-sea CO₂ flux) as well as the impact of iron limitation and upper ocean iron cycling.