Biogenic IOdine MeAsurements in Svalbard Snow (BIOMASS)

A new proxy based on iodine emission from sea-ice-associated phytoplankton and macro and micro algae is here proposed. During spring algal bloom in fact, the increase of chlorophyll concentration in the water has been observed to be accompanied also with an increase of tropospheric iodine species emission1 related the metabolism of marine organisms (Manley, 2002). The aim of the BIOMASS project is to collect multiple snow and ice samples to test the reliability a new potential proxy (Iincrese) for long-term MPP and sea ice reconstructions : I increase = [ I(snow) ] / ([Na(snow)] x [ I/Na](sea water)) with [ I / Na] (sea water) = 5,6 x 10-06 This proxy is based on the hypothesis that an increment of I/Na ratio in snow (normalized over sea water ratio) could reflect an increase of biogenic iodine (CH3I , CH2I2) emitted due to a change in the ocean conditions (i.e. warmer SST). In particular, this study wants to investigate the sources, transport, deposition and stability of total iodine in Svalbard surface snow layer collected from early April to the end of May: a period encompassing reasonably the pre and post seasonal biological bloom that occurs in the surrounding shelf waters west of Ny-Ålesund. To achive this goal, a multiple snow sampling in the surrounding of the accessible Gruvebadet Observatory will be carried on for all the period indicated. Futhermore, two transects along the profile Kongsvegen and Holtedahlfonna glaciers will be necessary to investigate the geographical distribution of iodine deposition. Finally, a shallow core (15 m) from the Holtedahlfonna glacier will be drilled to compare the I/Na increment in ice with satellite measurements of chlorophyll-a in order to evaluate the applicability of this new proxy for paleoclimate studies. Complementary, back trajectory analyses will be used to define the sources and transport mechanisms of biogenic iodine and major ions.