Author: Neža  Orel,   (National Institute of Biology)

Designation: 

Description:
Coastal marine areas face various pressures induced by human activities, such as wastewater discharges. The input of nutrients, pollutants and allochthonous microorganisms via wastewater can affect the abundance and diversity of bacterioplankton in marine waters. To explore the impact of wastewater pollution on bacterioplankton communities in the semi-enclosed Northern Adriatic Sea (Gulf of Trieste), we conducted one-year seasonal survey with high spatial resolution in the direction of dilution gradient from two wastewater sources (i.e., discharge to the river estuary and via submarine pipeline). Analyses of 16S rRNA gene amplicon sequences revealed that the composition of bacterioplankton communities at all sampling sites, regardless of distance from wastewater sources, was primarily driven by seasonal changes. Independent of seasonal changes, representatives of well-known microbial indicators of wastewater pollution were observed at all sites (e.g., Bacteroidaceae, Vibrionaceae, and Arcobacteraceae), and were linked to their source at the estuary discharge using microbial source tracking. Among these indicator taxa, Arcobacteraceae had the highest relative sequence abundance (up to 36% of sequences). Further phylogenetic analysis revealed that the amplicon sequences of Arcobacteraceae in our dataset were affiliated with the pathogenic Arcobacter cryaerophilus. Although the impact of wastewater discharges is restrained due to advanced treatment technologies, our results suggest that a potential exposure risk to bacterial pathogens in anthropogenically-impacted coastal zones remains.

Category: Scientific Program Abstract > Special Sessions > SS56 Coping with the stress: Microbial responses to natural and anthropogenic perturbations in aquatic environments