Kelp farming is an emerging industry in Alaska intended to improve food security and generate employment opportunities. According to University of Alaska Fairbanks researchers, kelp cultivation may also offer a large-scale method for removing carbon and nitrogen from coastal waters to enhance marine environmental quality and combat climate change.

The water-filtering prowess of farmed kelp was studied at two mixed-species kelp farms in Alaska during the 2020 to 2021 growing season. Analysis of tissue and seawater samples showed that seaweed species may have different capabilities to remove nutrients from their surroundings. Ribbon kelp proved more effective than sugar kelp at absorbing both nitrogen and carbon; nitrogen was 87.5% higher and carbon was 29.8% higher. However, that difference was somewhat offset by the higher density of farmed sugar kelp forests.

Sugar kelp at an experimental farm near Juneau, Alaska. Source: Schery Umanzor/University of Alaska Fairbanks

The researchers plan to increase the number of kelp farming plots assessed and replicate this effort at the sites already monitored to evaluate differences across farming seasons. The resulting data will extend that reported in the Aquaculture Journal.