南極の氷床氷河・海氷域における微量金属の動態

抄録

This review summarized the current status of trace metals research in the Cryosphere and identified subjects of research that need to be addressed. This paper outlined the characteristics and origin of bioactive trace metals (Bioact TMs) in the ice sheet, glaciers, and sea ice with focusing on the Antarctic region. The melting of glaciers and sea ice has a non-negligible impact on the distribution of Bioact TMs concentrations in seawater. Uncertainties in Bioact TMs fluxes associated with these ice melting remain large. Studies are needed to quantify Bioact TMs fluxes via meltwater accurately, including clarification of the removal mechanisms of Bioact TMs when the freshwater mixes into seawater. This paper also outlined that the melting of glaciers and sea ice affects primary production in the euphotic zone by enhancing upper-ocean stratification. Yet, the impact of ice-derived Bioact TMs on primary production is not well understood. Studies are needed to clarify the bioavailability of Bioact TMs supplied by meltwater, especially for the particulate form. The Antarctic ice sheet and glaciers are currently losing mass due to the submarine melting and calving of ice shelves, as well as the ocean warming. Although no statistically significant change in the sea ice extent in the Antarctic region to date, it will begin to decline in the next hundred years, given the current status of the ocean warming. Research will become important to investigate how melting of ice affects the biogeochemical cycles of Bioact TMs and how it changes the marine ecosystem.