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SUMMARY:Sources and sinks of bioactive trace metals across the western Ant
 arctic Peninsula shelf - Amber Annett\, Rutgers University
DTSTART:20170309T110000Z
DTEND:20170309T120000Z
UID:TALK71499@talks.cam.ac.uk
CONTACT:Dr Christian Buckingham
DESCRIPTION:In the high-nutrient low-chlorophyll waters of the Antarctic C
 ircumpolar Current (ACC)\, phytoplankton are limited by availability of ir
 on (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 lit
 tle is known about the cycling and biogeochemistry of trace metals across 
 the WAP shelf. Accordingly\, understanding the sources and cycling of trac
 e metals is crucial to predicting how the WAP ecosystem will respond to on
 going changes in sea-ice dynamics\, regional circulation and glacial meltw
 ater inputs. I will present the first spatially extensive\, multi-year stu
 dy of dissolved and particulate trace metals from this region\, collected 
 from surface waters of the ~200 x 700 km Palmer Long-Term Ecological Resea
 rch (Pal-LTER) grid during three summer cruises (Jan\, 2010-2012)\, with f
 ull water-column sampling for an additional two summers (Jan\, 2015 & 2016
 ).\n\nCoastal and benthic Fe inputs result in very high Fe concentrations 
 in some locations\, but we also observe very low dissolved (<0.15 nM) and 
 particulate (<0.2 nM) Fe concentrations in surface waters\, similar to val
 ues observed previously in open Southern Ocean waters\, extending far onto
  the shelf in some years. Evidence from other bioactive trace metals (e.g.
  Cu\, Zn) further suggests Fe limitation in western grid stations\, and ar
 gues for strong biological control of metal cycling in our sampling region
 . This dataset allows us to characterise the main sources of Fe and other 
 bioactive metals to surface and deep waters of the WAP shelf\, and suggest
 s episodic export of metal-replete shelf waters to the ACC.
LOCATION:British Antarctic Survey\, Innovation Centre\, Seminar Room 2
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