Spatiotemporal change in coastal waters caused by land-based fish farm wastewater-borne nutrients: Results from Jeju Island, Korea

• Published in: Marine pollution bulletin 2021-09, Vol.170, p.112632-112632, Article 112632
• Main Authors: Oh, Yong Hwa, Kim, Yongcheol, Park, Sang Rul, Lee, Taehee, Son, Young Baek, Park, Sung-Eun, Lee, Won Chan, Im, Dong-Hoon, Kim, Tae-Hoon
• Format: Article
• Language: English
• Subjects: Agricultural wastes; Aquaculture; Biological production; Coastal waters; Coastal zone; Coastal zones; Colored dissolved organic matter; Colour; Contaminants; Dissolved inorganic nutrients; Dissolved organic carbon; Dissolved organic matter; Fish; Fish culture; Fish farm wastewater; Fish farms; Groundwater; Jeju Island; Mineral nutrients; N:P ratio; Nitrogen; Nutrient concentrations; Nutrients; Offshore; Organic carbon; Pollution sources; Quality assessment; Seawater; Terrestrial environments; Trace contaminants; Wastewater; Wastewater discharges; Water quality
• ISSN: 0025-326X; 1879-3363
• DOI: 10.1016/j.marpolbul.2021.112632

Abstract We investigated spatiotemporal distributions of dissolved inorganic nutrients and organic carbon (DOC) and nitrogen (DON) in coastal waters and land-based fish farm wastewater to determine effects of wastewater on seawater of Jeju Island, Korea. The nutrient concentrations in seawater were lower than in wastewater with negative correlations against salinity, indicating a terrestrial source. Wastewater-derived DOC and DON were transported offshore while wastewater-derived inorganic nutrients were effectively removed, likely via biological production, and this was closely linked to decline in N:P ratios. The correlations between DOC, DON, and colored dissolved organic matter suggest that organic matters likely originate from the fish farm wastewater. Quantitatively, the estimated wastewater-derived DOC flux was equivalent to that through submarine groundwater, which is a significant water source on the island. Our results will be able to trace contaminant sources and support assessments of seawater quality for appropriate regulation of fish farm wastewater discharge into coastal zones. •Dissolved nutrients were measured to determine effect of fish–farm wastewater.•CDOM was used as a tracer to identify the origins of DOM in seawater.•Fish–farm wastewater can result in organic matter pollution in coastal waters.