The potential for large-scale kelp aquaculture to counteract marine eutrophication by nutrient removal

Large-scale kelp aquaculture offers several opportunities to counteract eutrophication. Here, six sites from Ailian Bay to its offshore waters in Rongcheng, northern China, were selected to investigate the spatiotemporal variations of kelp (Saccharina japonica) and seawater concentrations of C, N, and P in 2017 and 2019 in order to assess nutrient removal by kelp farming. Variations in biological parameters and elemental nutrient concentrations of whole thalli were also quantified in 2015 and 2016. We found that kelp farming in Ailian Bay can remove 1309 tons of C, 104 tons of N, and 12 tons of P. The increase of total suspended matter and nutrient concentrations from the coast to offshore waters supports the hypothesis of nutrient removal by farmed kelp. This study provides evidence of the bioremediation potential of farmed kelp.

Automated summary

Large-scale kelp aquaculture in Ailian Bay, northern China, can remove 1309 tons of carbon, 104 tons of nitrogen, and 12 tons of phosphorus, effectively combating eutrophication. The study provides evidence for the hypothesis that farmed kelp can remove nutrients and demonstrates the bioremediation potential of kelp farming.