Abstract

In the high-nutrient low-chlorophyll waters of the Antarctic Circumpolar Current (ACC), phytoplankton are limited by availability of iron (Fe). Iron limitation has also been suggested to influence productivity in western Antarctic Peninsula (WAP) shelf waters, although studies from Ryder Bay have identified significant Fe inputs from coastal sources and only rare instances of Fe depletion to limiting levels. Overall, very little is known about the cycling and biogeochemistry of trace metals across the WAP shelf. Accordingly, understanding the sources and cycling of trace metals is crucial to predicting how the WAP ecosystem will respond to ongoing changes in sea-ice dynamics, regional circulation and glacial meltwater inputs. I will present the first spatially extensive, multi-year study of dissolved and particulate trace metals from this region, collected from surface waters of the ~200×700 km Palmer Long-Term Ecological Research (Pal-LTER) grid during three summer cruises (Jan, 2010-2012), with full water-column sampling for an additional two summers (Jan, 2015 & 2016).

Coastal and benthic Fe inputs result in very high Fe concentrations in some locations, but we also observe very low dissolved (