Microbial community structure and metabolic profile of anthropized freshwater sediments from Argentina to develop sustainable management strategies

STAREVICH, V.A.; MADUEÑO, L.; FESTA, S.; AGNELLO, A.C.; LAYÚN, F.; CECOTTI, M.; ONETTO, M.E.; MORELLI, I.S.

Lausanne

Simposio; 18th International Symposium on Microbial Ecology; 2022

International Society for Microbial Ecology

Linking microbial community structure (MCS) with physicochemistry of freshwater courses allows a better understanding of its ecology and sustainable management strategies. Therefore, we evaluated the sediment MCS and the metabolic profile in channels of Río de La Plata estuary affected by oil refinery industrials (channels C, D and E) and urban discharges (channel C).Total (TH), aliphatic (AlH) and aromatic hydrocarbons (ArH) were measured in surface sediments and waters (GC-FID). Dissolved oxygen (DO), redox potential (RP) and pH were also determined for the latter. DNA extraction was performed from sediments, following sequencing of 16S rRNA gene V4 region (Ion Torrent), taxonomical assignment (QIIME2) and functional prediction (PICRUSt2).The lowest, middle, and highest values of pH, DO, RP, TH, AlH and ArH were detected in C, E and D, respectively. PCoA analysis showed different MCS among sites, which were not related to TH concentration (PERMANOVA). Significant predominant taxa were: Rhodobacteraceae, Sphingomonadaceae, Rhodocyclaceae and Anaerovoraceae in C, and Syntrophales, Methanoregulaceae, and Methylomonadaceae in D. Functional prediction suggested that fermentative pathways were higher in C and E, than in D, while methanogenesis and carbon fixation pathways were higher in D and E, than in C (Mann-Whitney/Kruskal-Wallis tests). Although TH did not explain the difference on MCS, urban discharges could act as selection pressure, decreasing pH, DO, RP and promoting taxa and pathways related to fermentative and heterotrophic metabolism in C. Despite D was the most hydrocarbon polluted site, it presented autotrophic, syntrophic, and methanogenic mechanisms commonly involved in natural processes in anoxic sediments.