engleski

Revealing bacteria diversity by metabarcoding methods in water and sediment in the Adriatic Sea

Seasonal sampling of the sea water and sediment was conducted on two sites affected by various anthropogenic activities in central and southern Adriatic during 2017. Total DNA was extracted from water and sediment samples and 16S rRNA high-throughput sequencing was performed, followed by bioinformatics analysis in QIIME2 and statistical analysis in RStudio. Core community on class level from water column was identified as Gammaproteobacteria/ Alphaproteobacteria/ Bacteroidia/ Oxyphotobacteria, and community composition was seasonally affected (Figure 1). Enrichment with other phyla occurs sporadically: Firmicutes during summer, Planctomycetes in autumn, Verrucomicrobia in spring and autumn (N fixating and polysaccharide degraders), Marinimicrobia (positively correlated to chlorophyll a concentration and seasonally stratification anoxia) in autumn. Cyanobacteria was represented with Prochlorococcus MIT9313 and Synechococcus CC9902 with the highest abundance in autumn and spring. Sediment core community was differentiated according to site type (anthropogenic influence – aquaculture vs. control site), and core community on class level was Bacteroidia/ Alphaproteobacteria/ Gammaproteobacteria/ Planctomycetacia (Figure 2). Aquaculture site displayed higher abundance of Chloroflexi, Epsilonbacteraeota and Spirochaetes. Chloroflexi are represented with class Anaerolineae, filamentous bacteria known as biofilm colonizer and for anaerobic digestion. Control sites (southern Adriatic) had more represented phyla Planctomycetes and Cyanobacteria (Xenococcaceae family, genera Pleurocapsa and Chrooccocidiopsis). Bacteria of genus Sulfuvorum (Epsiolonbactaerota), known for role of oxidation and reduction of reduced S compounds in organic and sulfidic rich sediments, was significantly more abundant in the aquaculture site (almost 50% in summer sample). Bacteroidetes was generally abundantly represented by Lutimonas and Maribacter, the former known as heterotrophic ammonia-oxidising bacteria, latter as important player in COD removal (decomposition of organic compounds).

bacteria ; matabarcoding ; aquaculture ; sediment

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