Project description:The Baltic Sea is one of the largest brackish water bodies in the world. Redoxclines that form between oxic and anoxic layers in the deepest sub-basins are a semi-permanent character of the pelagic Baltic Sea. The microbially mediated nitrogen removal processes in these redoxclines have been recognized as important ecosystem service that removes large proportion of the nitrogen load originating from the drainage basin. However, nitrification, which links mineralization of organic nitrogen and nitrogen removal processes, has remained poorly understood. To gain better understanding of the nitrogen cycling in the Baltic Sea, we analyzed the assemblage of ammonia oxidizing bacteria and archaea in the central Baltic Sea using functional gene microarrays and measured the biogeochemical properties along with potential nitrification rates. Overall, the ammonia oxidizer communities in the Baltic Sea redoxcline were very evenly distributed. However, the communities were clearly different between the eastern and western Gotland Basin and the correlations between different components of the ammonia oxidizer assemblages and environmental variables suggest ecological basis for the community composition. The more even community ammonia oxidizer composition in the eastern Gotland Basin may be related to the constantly oscillating redoxcline that does not allow domination of single archetype. The oscillating redoxcline also creates long depth range of optimal nitrification conditions. The rate measurements suggest that nitrification in the central Baltic Sea is able to produce all nitrate required by denitrification occurring below the nitrification zone.
Project description:Analysis of bacterial fraction collected on GF/F filters post pre-filtration on 1um filter. 15L were filtered from Bering Strait (BSt) surface water and Chukchi Sea (station 2) bottom waters.
Project description:In this study, transcriptomics was used to investigate Atlantic salmon (Salmo salar) sampled from three different field locations within Baltic Sea (Baltic Main Basin (CBS), Gulf of Finland (GoF) and Bothnian Sea (BS)) during marine migration. RNA labeling, hybridizations, and scanning were performed by the Finnish Microarray and Sequencing Centre in Turku Centre for Biotechnology.
Project description:The Atlantic cod (Gadus morhua L.) is one of the most important species in the Baltic Sea with high ecological and economical value. To explore the differences in adaptation to salinity between Baltic cod from different regions, western (Kiel Bight) and eastern (Gdańsk Bay) samples were analyzed through oligonucleotide microarray.
Project description:The Atlantic cod (Gadus morhua L.) is one of the most important species in the Baltic Sea with high ecological and economical value. To explore the differences in adaptation to salinity between Baltic cod subpopulation: western (Kiel Bight) and eastern (Gdańsk Bay) samples were analyzed through genome-wide oligonucleotide microarray.
Project description:The experiment compared flounder from the North Sea and the Baltic sea and their reactions on being exposed to water of different salinities
Project description:Ammonia-oxidizing archaea (AOA) have been reported at high abundance in much of the global ocean, even in environments such as pelagic oxygen minimum zones (OMZs), where conditions seem unlikely to support aerobic ammonium oxidation. Due to the lack of information on any potential alternative metabolism of AOA, the AOA community composition might be expected to differ between oxic and anoxic environments, indicating some difference in ecology and/or physiology of the AOA assemblage. This hypothesis was tested by evaluating AOA community composition using a functional gene microarray that targets the ammonia monooxygenase gene subunit A (amoA). The relationship between environmental parameters and the biogeography of the Arabian Sea and the Eastern Tropical South Pacific (ETSP) AOA assemblages was investigated using principal component analysis (PCA) and redundancy analysis (RDA). In both the Arabian Sea and the ETSP, AOA communities within the core of the OMZ were not significantly different from those inhabiting the oxygenated surface waters above the OMZ. The AOA communities in the Arabian Sea were significantly different from those in the ETSP. In both oceans, the abundance of archaeal amoA gene in the core of the OMZ was higher than that in the surface waters. Our results indicate that AOA communities are distinguished by their geographic origin. RDA suggested that temperature was the main factor that correlated with the differences between the AOA communities from the Arabian Sea and those from the ETSP. Physicochemical properties that characterized the different environments of the OMZ and surface waters played a less important role than did geography in shaping the AOA community composition.
