[A-CG45] 海洋表層－大気間の生物地球化学

[ACG45-04] A novel probe to sample trace-metal concentrations in sea ice at high vertical resolution

*Matthew Corkill¹、Takenobu Toyota²、Daiki Nomura^3,4,5、Klaus Martin Meiners^6,7,8、Pat Wongpan⁶、Trevor Corkill⁹、Delphine Lannuzel^1,8 (1.Institute for Marine and Antarctic Studies, University of Tasmania, Hobart, TAS, Australia、2.Institute of Low Temperature Science, Hokkaido University, Sapporo, Hokkaido, Japan、3.Field Science Center for Northern Biosphere, Hokkaido University, Hakodate, Hokkaido, Japan、4.Arctic Research Center, Hokkaido University, Sapporo, Hokkaido, Japan、5.Faculty/Graduate school of Fisheries Sciences, Hokkaido University, Hakodate, Hokkaido, Japan、6.Australian Antarctic Program Partnership, Institute for Marine and Antarctic Studies, University of Tasmania, Hobart, TAS, Australia、7.Department of Climate Change, Energy, the Environment and Water, Australian Antarctic Division, Kingston, TAS, Australia、8.Australian Centre for Excellence in Antarctic Science, Institute for Marine and Antarctic Studies, University of Tasmania, Hobart, TAS, Australia、9.Antec Proprietary Limited, Midvale, WA, Australia)

Inside sea ice impermeable layers trap material as well as highly porous layers full of ice algae. These features can be smaller than a few centimetres but are important for understanding biogeochemical cycles in sea ice. Traditionally, sea-ice samples are collected from ice cores cut into sections to obtain a vertical profile. However, drawbacks to this method include difficulty cutting sections smaller than a few centimetres thick and contamination of the samples during high-resolution sectioning. Brines may also drain out and be lost, meaning that important environments in sea ice may be overlooked or misrepresented. To address this, we developed a sea-ice melt probe that bores into sea ice and collects high-resolution samples without extracting and cutting ice cores. The melt-probe’s capability was tested during February-March 2023 at Saroma-ko Lagoon, Japan. Experiments consisted of testing the effect of the melt-probe set temperature, its high-resolution capability, and ability to be deployed on snow-covered sea ice. Complimentary laboratory-based experiments included testing how well the melt-probe delineates layers by introducing a fluorescent layer to artificial sea ice. This proof-of-concept study hopes to provide an alternative method of sampling sea ice with the ability to support new research into the fine-scale structure of sea ice, with applications spanning challenging fields of research such as trace metal, microplastics and gas.