The Role of Ice Melting in Providing Available Iron to the Surface Water of the Eastern Bering Sea Shelf

Researchers:Jingfeng Wu and Ana Aguilar-Islas
Funding Source: NSF. JAMSTEC funds are being used for Aguilar-Islasí salary from August 2008 March 2009
Collaborators: Robert Rember (IARC), Calvin Mordy (GENWEST), Phyllis Stabenoís lab (NOAA), and other BEST PIs

The goal of this project is to assess the role of sea ice-derived iron in the eastern Bering Sea during spring.

We collected water column and sea ice samples during the Bering Ecosystem STudy (BEST) spring 2007 and spring 2008 cruises. Dissolved iron and acid dissolvable iron were measured in sea ice and water column samples. The obtained iron values are put into context using hydrographic and biological data collected during these cruises by other BEST groups.

Preliminary results from spring 2007 suggests sea ice plays an important role in supplying the essential micronutrient iron during spring phytoplankton blooms that develop at the ice edge in the outer shelf and shelf break. This is because external sources of iron other than melting sea ice in the outer shelf and shelf break of the Bering Sea are limited. In contrast over the mid and inner shelf, sedimentary sources can readily supply iron to the water column, making the contribution from melting sea ice a less important source.

Observational and modeling studies in the Bering Sea indicate that the extent and duration of the seasonal ice cover influence the timing of the spring bloom and its phytoplankton community composition. This project will elucidate the importance of melting sea ice in providing the micro-nutrient iron, and the potential role of this iron source in influencing the spring algal bloom in the Bering Sea. In addition, this project will provide water column and ice iron data to be incorporated into a Bering Sea ecosystem model.