Incorporation of nitrogen compounds into sea ice from atmospheric deposition

• Published in: Marine Chemistry
• Main Authors: Nomura, D, McMinn, A, Hattori, H, Aoki, S, Fukuchi, M
• Format: Article in Journal/Newspaper
• Language: English
• Published: Elsevier Science Bv 2011
• Subjects: Biological Sciences; Ecology; Marine and Estuarine Ecology (incl. Marine Ichthyology); Okhotsk; Sea ice
• Online Access: https://doi.org/10.1016/j.marchem.2011.08.002; http://ecite.utas.edu.au/86462

Temporal measurements of temperature, salinity, wateroxygen isotopic ratio and nutrient concentrations atSaroma-ko Lagoon, southern Sea of Okhotsk, were made in FebruaryMarch 2008 to examine the processes bywhich nitrogen compounds from the atmosphere were incorporated via snowfall into sea ice. Granular icemade up more than half the ice thickness, and the mass fraction of snow in the snow-ice layer on top of the iceranged from 0.8% to 46.9%. The high concentrations of NO 3 − + NO 2 − and NH 4 + observed in the snow and snowice throughout the study period were likely due to the proximity of the study site, in northern Japan, to the east coast of the Asian continent. Pollutants containing high NO 3 − and NH 4 + concentrations are transported from East Asia and deposited in snowfall over the sea ice in the southern part of the Sea of Okhotsk. Compared with NO 3 − + NO 2 − and NH 4 + concentrations, PO 4 3− concentrations in the snow and snow-ice were low. The strong correlation between the NO 3 − + NO 2 − and NH 4 + concentrations in the snow-ice and the mass fraction of snow indicates that the nitrogen compounds on top of the sea ice were controlled mainly by the snow contribution to the sea ice when snow-ice predominated. Our results indicate that chemical cycles in sea ice can be affected by polluted precipitation (snow) originating from a nonpolar sea.