Natural Variations in the Benthic Environment and Bacterial Communities of Coastal Sediments around Aquaculture Farms in South Korea.

ABSTRACT

The aim of this study was to examine the possible seasonal variations in the nutrients (dissolved inorganic nitrogen-DIN and phosphorus) and benthic bacterial communities in marine aquaculture surrounding sediments. The study areas were Geoje, Tongyeong, and Changwon bays in Korea, which are famous for oysters (Magallana gigas), Halocynthia roretzi, and warty sea squirt (Styela clava) farming, respectively. The study sites included semi-enclosed coastal areas with a low seawater exchange rate. Subtidal sediment samples were collected seasonally from the area surrounding the aquacultures between April and December 2020. Seasonal variations in nutrients were observed, with the highest concentration of DIN in August. For phosphorus, site-specific variations were also observed. To investigate the variations in benthic bacterial communities, the advanced technique of 16S rRNA gene amplicon sequencing was applied, and the results indicated a seasonal variation pattern and predominance of Proteobacteria (59.39-69.73%), followed by Bacteroidetes (6.55-12.85%) and Chloroflexi (2.04-4.50%). This study provides a reference for future studies on natural variations in the benthic environment and bacterial communities in the areas surrounding aquacultures. Supplementary Information The online version contains supplementary material available at 10.1007/s12088-023-01067-8.