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IPY-OSC Francisco Fernandoy-46
APECS is an international and interdisciplinary organization for undergraduate and graduate students, postdoctoral researchers, early faculty members, educators and others with interests in Polar Regions and the wider cryosphere. Our aims are to stimulate interdisciplinary and international research collaborations, and develop effective future leaders in polar research, education and outreach. We seek to achieve these aims by:
  • Facilitating international and interdisciplinary networking to share ideas and experiences and to develop new research directions and collaborations;
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KitaeKim2010aAuthor(s):
Kitae Kim*, Wonyong Choi*, Michael R. Hoffmann**, Ho-Il Yoon***, Byong-Kwon Park***

*School of Environmental Science and Engineering, Pohang University of Science and Technology (POSTECH), Pohang 790-784, Korea **W. M. Keck Laboratories, California Institute of Technology, Pasadena, CA, USA ***Korea Polar Research Institute, Incheon, Korea

Originally Presented at:
IPY Oslo Science Conference, Oslo, Norway 8-12 June 2010

Abstract:
The availability of iron has been thought as a main limiting factor for the phytoplankton productivity and related with the uptake of atmospheric CO2 and algal blooms in fresh and sea waters. In this work, the formation of bio-available iron (Fe(II)aq) from the dissolution of iron oxide particles was investigated in ice phase under both UV and visible light irradiation. The photoreductive dissolution of iron oxides proceeded slowly in aqueous solution (pH 3.5) but was significantly accelerated in polycrystalline ice with subsequently releasing more bioavailable ferrous iron upon thawing. The enhanced photogeneration of Fe(II)aq in ice was confirmed regardless of the type of iron oxides [hematite, maghemite (?-Fe2O3), goethite (?-FeOOH)] and the kind of electron donors. The ice-enhanced dissolution of iron oxides was also observed under visible light irradiation although the dissolution rate was much slower compared with the case of UV radiation. The iron oxide particles and organic electron donors (if any) in ice are concentrated and aggregated in the liquid-like grain boundary region (freeze concentration effect) where protons are also highly concentrated (lower pH). The enhanced photodissolution of iron oxides should occur in this confined boundary region. We hypothesized that electron hopping through the interconnected grain boundaries of iron oxide particles facilitates the separation of photoinduced charge pairs. The outdoor experiments carried out under ambient solar radiation of Ny-Alesund (Svalbard, 78.55 N) also showed that the generation of dissolved Fe(II)aq via photoreductive dissolution is enhanced when iron oxides are trapped in ice. Our results imply that the ice(snow)-covered surfaces and ice-cloud particles containing iron-rich mineral dusts in the polar and cold environments provide a source of bioavailable iron when they thaw.

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Featured Member

Michael_Laiho

Arctic Centre (University of Lapland), Finland

Born on 19th October 1984, Michael John Laiho is half Finnish, half British and living in Finland since 2010. In 2010 he graduated from the London School of Economics and Political Science (LSE) in London, after which time he decided to do his Finnish military conscription and subsequently moved to Finland that year. After completing his military service in Pori, he has started a PhD at the Arctic Centre (University of Lapland) on the topic of the EU’s influence in Arctic governance. So far he is in his second year, has attended and presented at various important conferences, nationally and internationally, and has published his work in peer-reviewed publications. For 2013 he is aiming to complete two student exchange programmes – one in Central Europe as part of Erasmus, and the other in the Arctic region as part of North2North. As a member of APECS he has volunteered to organize the next Arctic Science Summit Week in Krawko in 2013 and wishes to organize an APECS conference some day at the Arctic Centre, in Rovaniemi. Outside of the scientific community, Michael is also a keen writer, artist and marathon runner.

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