Primary production and biochemical compositions in Arctic melt ponds.

Abstract:

Areal extent of melt ponds within sea ice recently have increased during the arctic summer but the biological impacts of these changes on the arctic marine ecosystem have rarely been studied. Our survey of environmental conditions in melt ponds was conducted in 22 at sea ice camp 1 and 11 ponds at camp 2, respectively during the Korean Arctic expedition in 2014. The temperature range of melt ponds showed low variability at sea ice camp 1 (-1.3~0.8 °C) and camp 2 (-1.5~0.4 °C). In contrast, the salinity represented high variations ranging from 0.1 to 26.8 (mean ± S.D. = 16.7 ± 10.8) and 0 to 26.9 (mean ± S.D. = 12.3 ± 11.6), respectively. The average chlorophyll a (chl-a) concentrations were 0.124 mg m^-2 (S.D. = ± 0.121 mg m^-2) and 0.158 mg m^-2 (S.D. = ± 0.067 mg m^-2) in melt ponds, respectively at camp 1 and camp 2. Middle sized cells of phytoplankton (2-20 µm) were predominant in melt ponds accounting for 78 % and 63 % of total chl-a concentration at camp 1 and 2, respectively. The carbon uptake rates of phytoplankton in melt ponds ranged from 0.001 to 0.080 mg C m^-3 h^-1 (mean ± S.D. = 0.025 ± 0.024 mg C m^-3 h^-1) at camp 1 and 0.022 to 0.21 mg C m^-3 h^-1 (mean ± S.D. = 0.077 ± 0.006 mg C m^-3 h^-1) at camp 2 which is about three times higher than those of camp 1. The biochemical compositions averaged from various melt ponds were 35% (S.D. = ± 14.9%), 40% (S.D. = ± 13.2%), and 25% (S.D. = ± 12.9%), respectively for lipids, carbohydrates, and proteins at camp 1. In comparison, the overall average compositions of lipids, carbohydrates, and proteins were 29% (S.D. = ± 11.4%), 51% (S.D. = ± 9.8%), and 20% (S.D. = ± 7.9%), respectively at camp 2.