Bioavailability of Dissolved Organic Matter Derived from Aquaculture and the Associated Microbial Community in the Water Column

Aquaculture introduces organic matter into the water column, mainly through unconsumed fish-feed and feces, from fish and mytilids. Chemical and biological parameters were evaluated at different distances from a salmon and mytilid farm in the Caucahué Channel. We observed higher concentrations of ammonium, dissolved proteins, and a higher Degradation-Index nearest to salmonid cage, along with a slightly less microbial diversity. Gammaproteobacteria and Bacteroidota increased its relative abundance, but Crenarchaeota and Thermoplasmatota decreased in the farm surrounding waters. This study indicates that aquaculture derived DOM is a source of labile substrate with implications for microbial communities that inhabits near to farms.