Stay connected with us
around the nation »

Help from Kelp

NOAA scientists investigate seaweed farming to mitigate ocean acidification

September 23, 2015

In the Pacific Northwest, NOAA scientists and partners are studying the potential for seaweed farms to help fight ocean acidification by removing carbon dioxide (CO2) from the ocean. The study is part of a collaborative $1.5 million project led by the Puget Sound Restoration Fund and funded by Vulcan Philanthropy.

Many seaweeds, including kelp, thrive in acidifying ocean waters. They take up CO2 and nutrients from their environment, improving water quality as they grow by drawing down levels of the dissolved acid along with nitrogen and phosphorus. Seaweeds also give off oxygen, which can help with dead zones. The combination may result in seaweed farms acting as protective “halos” that mitigate acidification and pollution locally while creating habitat for marine species. When the seaweed is harvested, it takes the excess carbon and nitrogen with it, effectively removing them from the ocean.

Led by Dr. Jonathon Davis, senior scientist, and Betsy Peabody, executive director, at the Puget Sound Restoration Fund, the 5-year project involves collaboration with NOAA’s Northwest Fisheries Science Center and Pacific Marine Environmental Laboratory. Using the Manchester Research Station and NOAA’s Kenneth K. Chew Center for Shellfish Research and Restoration, kelp sporophytes (seedlings) will be cultured and seeded onto twine for deployment and growth at an existing aquaculture facility in north Hood Canal. The lab will undertake water quality monitoring.

The project will address more than just the seaweed’s potential to mitigate ocean acidification. A goal for a future study is to harvest kelp and develop useful kelp products. These potentially carbon-neutral products could help stimulate new industries based on “blue carbon.” Although it constitutes a minor portion of marine aquaculture in the United States, the cultivation of aquatic plants globally produced an impressive 26.1 million metric tons in 2013, most of which was seaweed. Seaweeds can be farmed without freshwater, arable land, or nutrient inputs, so they are ecologically and economically efficient sources of biomass.

Eventually, the project looks to develop the seaweeds it cultivates as food and other products that can support local communities and businesses, as well as potentially generate new bio-products. The Northwest Fisheries Science Center’s Montlake Laboratory will be involved in seaweed product development later in the project.

Changing conditions—especially ocean acidification—in U.S. coastal waters like Puget Sound threaten to disrupt the ecosystem and the livelihoods of surrounding coastal communities. The project’s unique approach hopes to show that seaweed farms can decrease acidification and nutrient pollution while providing habitat, basically creating underwater refuges in an urban estuary.