Project description:The experiment was designed to study the transcriptomic response of the centric diatom Skeletonema marinoi to the presence of cues from the grazer Calanus finmarchicus. Samples were collected in triplicate after 65 and 89 hours of exposure of diatom cells to the copepods. Control samples with no copepods were collected at the same time points.
Project description:Purpose:Using Illumina high-throughout sequencing technology, the transcriptome and expression profiles of S. marinoi were sequenced and analyzed. Comprehensive and systematic study of transcriptomic characteristics, analysis of characteristics of Digital Gene Expression Profiling during different growth phase and deep exploration of molecular mechanism for response to the temperature and low silicate stress environment will provide a comprehensive insight into gene expression profiles and provides an important gene resource for future genetic and molecular studies of S. marinoi and other Skeletonema family diatom.
Project description:Rising atmospheric CO2 concentrations are leading to ocean acidification, altering the inorganic carbon buffer system with consequences for marine organisms. Here we applied RNA-seq and iTRAQ quantification to investigate the potential impacts of ocean acidification on the temperate coastal marine diatom Skeletonema marinoi.
Project description:The comparision between gradual ocean acidification (GC) and one way ocean acidification (HC) of physiological and molecular responses on diatom Skeletonema costatum
Project description:The aim of the experiment was to study the gene expression changes occurring when cells of the diatom Skeletonema marinoi undergo sexual reproduction. In this species, sex can be induced by an environmental trigger, specifically a change in salinity of the cultivation media. In diatoms the unique mode of cell division with unequal inheritance of the rigid cell wall components determines a progressive cell size reduction as cells divide. Large cells above a given size threshold are not competent for sex, on the other hand small cells, under appropriate conditions, can undergo sexual reproduction. RNA-seq included three experimental conditions: a) large cells above the sexualization size threshold, grown at standard salinity (control condition: no sex, no salinity stress); b) large cells above the sexualization size threshold transferred to higher salinity (treatment 1: no sex, salinity stress); c) small cells below the sexualization size threshold transferred to higher salinity (treatment 2: sex, salinity stress).
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.