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:We sampled the microbial community at the sea ice edge in McMurdo Sound, Ross Sea at the same location (-77.62S, 165.41E) for four weeks (as described in Wu et al 2019, Nat. Comms.). We had four sampling dates corresponding to weeks 1 to 4: December 28 2014, January 6, 15, and 22 2015. Large volumes of water (150--250 L) were filtered from 1 m depth at the sea ice edge, and passed through three filters sequentially (3.0, 0.8, and 0.1 um, each 293 mm Supor filters). Filters with collected biomass were then placed in tubes with a sucrose-based preservative buffer (20 mM EDTA, 400 mM NaCl, 0.75 M sucrose, 50 mM Tris-HCl, pH 8.0) and stored at -80 C until sample processing. We extracted proteins after buffer exchange into a 3\% SDS solution as previously described Wu et al 2019, Nat. Comms.
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: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.
