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Kaartokallio, H., Kuosa, H., Thomas, D. N., Granskog, M. A., & Kivi, K. (2006). Biomass, composition and activity of organism assemblages along a salinity gradient in sea ice subjected to river discharge in the Baltic Sea. Polar Biol, 30(2), 183–197.
Abstract: A study was undertaken to examine the activity and composition of the seasonal Baltic Sea land-fast sea-ice biota along a salinity gradient in March 2003 in a coastal location in the SW coast of Finland. Using a multi-variable data set, the less well-known algal and protozoan communities, and algal and bacterial production in relation to the physical and chemical environment were investigated. Also, the first coincident measurements of bacterial production and dissolved organic matter (DOM) in a sea-ice system are reported. Communities in sea ice were clearly autotrophy-dominated with algal biomass representing 79% of the total biomass. Protozoa and rotifers made up 18% of biomass in the ice and bacteria only 3%. Highest biomasses were found in mid-transect bottom ice. Water column assemblages were clearly more heterotrophic: 39% algae, 12% bacteria and 49% for rotifers and protozoa. Few significant correlations existed between DOM and bacterial variables, reflecting the complex origin of ice DOM. Dynamics of dissolved organic carbon, nitrogen and phosphorus (DOC, DON and DOP) were also uncoupled. A functional microbial loop is likely to be present in the studied ice. Existence of an under-ice freshwater plume affects the ecosystem functioning: Under-ice water communities are influenced directly by river-water mixing, whereas the ice system seems to be more independent–the interaction mainly taking place through the formation of active bottom communities.
Notes: Sampling: Nine stations along a 40km salinity gradient from inner Pojo Bay through the Archipelago to the edge of the open sea
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Steffens, M., Granskog, M. A., Kaartokallio, H., Kuosa, H., Luodekari, K., Papadimitriou, S., et al. (2006). Spatial variation of biogeochemical properties of landfast sea ice in the Gulf of Bothnia, Baltic Sea. In Annals of Glaciology (Vol. 44, pp. 80–87). Cambridge: International Glaciological Society.
Abstract: Horizontal variation of landfast sea-ice properties was studied in the Gulf of Bothnia, Baltic Sea, during March 2004. In order to estimate their variability among and within different spatial levels, 72 ice cores were sampled on five spatial scales (with spacings of 10 cm, 2.5 m, 25 m, 250 m and 2.5 km) using a hierarchical sampling design. Entire cores were melted, and bulk-ice salinity, concentrations of chlorophyll a (Chl a), phaeophytin (Phaeo), dissolved nitrate plus nitrite (DIN) as well as dissolved organic carbon (DOC) and nitrogen (DON) were determined. All sampling sites were covered by a 5.5-23 cm thick layer of snow. Ice thicknesses of cores varied from 26 to 58 cm, with bulk-ice salinities ranging between 0.2 and 0.7 as is typical for Baltic Sea ice. Observed values for Chl a (range: 0.8-6.0 μg Chl a l-1; median: 2.9 μg Chl a l -1) and DOC (range: 37-397 μM; median: 95 μM) were comparable to values reported by previous sea-ice studies from the Baltic Sea. Analysis of variance among different spatial levels revealed significant differences on the 2.5 km scale for ice thickness, DOC and Phaeo (with the latter two being positively correlated with ice thickness). For salinity and Chl a, the 250 m scale was found to be the largest scale where significant differences could be detected, while snow depth only varied significantly on the 25 m scale. Variability on the 2.5 m scale contributed significantly to the total variation for ice thickness, salinity, Chl a and DIN. In the case of DON, none of the investigated levels exhibited variation that was significantly different from the considerable amount of variation found between replicate cores. Results from a principal component analysis suggest that ice thickness is one of the main elements structuring the investigated ice habitat on a large scale, while snow depth, nutrients and salinity seem to be of secondary importance.
Keywords: Sea ice; Fast ice; Sea ice properties; Ice algae; Chlorophyll; Biogeochemistry; Nutrients (mineral); Particulate organic matter; Dissolved organic matter; Salinity; Spatial scale; Spatial variability; Horizontal patchiness; Sampling design; Brackish water; Ane; Baltic Sea; Gulf of Bothnia
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Steffens, M., Granskog, M. A., Kaartokallio, H., Kuosa, H., Luodekari, K., Papadimitriou, S., et al. (2006). Spatial variation of biogeochemical properties of landfast sea ice in the Gulf of Bothnia, Baltic Sea. In Proceedings of the International Symposium on Sea Ice, Dunedin (New Zealand), 5-9 Dec 2005 (pp. 80–87). Annals of Glaciology, 44. Cambridge: International Glaciological Society.
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Steffens, M., Granskog, M. A., Kaartokallio, H., Kuosa, H., Luodekari, K., Papadimitriou, S., et al. (2006). Spatial variation of biogeochemical properties of landfast sea ice in the Gulf of Bothnia, Baltic Sea. In Proceedings of the International Symposium on Sea Ice, Dunedin (New Zealand), 5-9 Dec 2005 (pp. 80–87). Annals of Glaciology, 44. Cambridge: International Glaciological Society.
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Steffens, M., Granskog, M. A., Kaartokallio, H., Kuosa, H., Luodekari, K., Papadimitriou, S., et al. (2006). Spatial variation of biogeochemical properties of landfast sea ice in the Gulf of Bothnia, Baltic Sea. In Proceedings of the International Symposium on Sea Ice, Dunedin (New Zealand), 5-9 Dec 2005 (pp. 80–87). Annals of Glaciology, 44. Cambridge: International Glaciological Society.
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