engleski

Long-term trends and biogeochemical cycling under euxinic condition in marine lake (Adriatic coast)

We explored a long-term chemical data along with the seasonal diversity and the abundance of bacterial and archaeal communities residing the chemocline, monimolimnion and sediment of marine meromictic Rogoznica Lake by quantitative PCR and high-throughput 16S rRNA gene sequencing of DNA and cDNA. The results revealed clear vertical stucture of microbial community with Gammaproteobacteria dominating the chemocline, Deltaproteobacteria dominating the monimolimnion and significantly higher archaeal abundance in the sediment. However, seasonal changes in the community structure were not pronounced. Quantitative PCR confirmed that their abundance remained stabile, with no significant changes over the sampling seasons.These communities were significantly influenced by temperature, dissolved organic carbon, sufide and phosphates concentration. Futrhermore, in contrast to findings in similar environments, diversity in Rogoznica Lake was found to be very low in both, DNA and RNA gene pools. This is likely the result of development of highly specialized taxa under relatively conserved region from the chemocline beneath. Thus, a biogeochemical cycling of carbon, nitrogen and sulfur is distributed amog limited number of taxa. Long- term data indicated that Rogoznica Lake exibits climate changes. Temperature increase, with consequently accumulation of sulfide and ammounium probably can lead to further weakening of some metabolic pathways and extinction of some taxa which could have deletoriuos concenquences on functioning of the Lake.

prokaryotic community, hypoxic/anoprokaryotic community ; hypoxic/anoxic marine environments ; climate change ; Rogoznica Lakexic marine environments, climate change, Rogoznica Lake

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