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SUMMARY:Investigating the impact of glacial retreat upon iron and macronut
 rient cycling along the West Antarctic Peninsula - Rhiannon Jones\, Univer
 sity of Southampton
DTSTART:20230927T120000Z
DTEND:20230927T130000Z
UID:TALK205531@talks.cam.ac.uk
CONTACT:Dr Michael Haigh
DESCRIPTION:Iron is an essential nutrient for marine primary producers yet
  is the primary (co-)limiting nutrient in much of the Southern Ocean. With
  continued regional warming\, the West Antarctic Peninsula\, home to 676 g
 laciers covering 95\,000 km2\, provides large fluxes of glacially sourced 
 meltwater to the marine environment. Understanding glacier-water column in
 teractions is important in evaluating the role of glaciers in Southern Oce
 an iron and macronutrient cycling\, and how this may change as regional at
 mospheric and oceanic warming continues. Using short-lived radium isotopes
 \, stable oxygen isotopes\, and physical parameters such as temperature an
 d salinity\, we determine the influence of sediment inputs and meltwater c
 ontributions upon water column macro and micronutrient distributions withi
 n glacially-influenced bays[1].\n\nFor iron\, we observe high dissolved (4
  – 8 nM) and particulate (30 – 580 nM) concentrations proximal (0.5 
 – 12 km) from the glacier edge. Recent studies indicate that iron-rich p
 articulates can be highly bioavailable\, if rich in iron(II) (ferrous iron
 )[2] [3]. Using Scanning Transmission X-ray Microscopy (STXM) and X-ray Ne
 ar Edge Spectroscopy (XANES)\, we investigate the iron speciation and co-l
 ocation with carbon to infer the potential bioavailability of iron in glac
 iogenic particulates. We observe a high iron(II) component of iron-rich pa
 rticles averaging 40%\, coupled with apparent stabilisation of iron(II) th
 rough organic carbon complexation. Transport of particulate iron beyond th
 e near-shore is also observed\, and so we infer that the West Antarctic Pe
 ninsula is an important source of potentially bioavailable particulate iro
 n across the wider shelf.\n\n1.	Jones\, R.L.\, et al.\, Continued glacial 
 retreat linked to changing macronutrient supply along the West Antarctic P
 eninsula. Marine Chemistry\, 2023. 251: p. 104230.\n2.	Shoenfelt\, E.M.\, 
 et al.\, High particulate iron (II) content in glacially sourced dusts enh
 ances productivity of a model diatom. Science advances\, 2017. 3(6): p. e1
 700314.\n3.	Wyatt\, N.J.\, et al.\, Phytoplankton responses to dust additi
 on in the Fe–Mn co-limited eastern Pacific sub-Antarctic differ by sourc
 e region. Proceedings of the National Academy of Sciences\, 2023. 120(28):
  p. e2220111120.\n\n\n
LOCATION:BAS Seminar Room 2\; https://ukri.zoom.us/j/94865119404
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