Sea Feeds: Identification and culture of Californian marine macroalgae capable of reducing greenhouse gas production from ruminant livestock

Project Number
Project Date Range
Funding Agency
California Ocean Protection Council (OPC)
Focus Area(s)
Sustainable Fisheries and Aquaculture

To address climate change in California beyond carbon-based gases, the state has recently passed legislation to reduce short-lived climate pollutants. In particular, the state aims for a 40% methane reduction by 2030. Several reductions may come through existing technologies associated with landfills and energy producers. However, the state’s largest contributor to methane production is cattle, specifically 1.4 million resident dairy cows and 1 million beef cattle.

Methods to reduce gases produced from cattle have largely been unexplored in California. However, recent research in Australia has shown that some species of sub-tropical seaweed can reduce methane production from cattle by up to 99% when used as a feed additive at 2% inclusion rates of organic matter. Temperate species of seaweed have not yet been assessed for methane reducing properties, but many of the species present in the California Current Ecosystem are closely related to these sub-tropical species.

In this project, researchers will conduct laboratory experiments to understand effects of 20 different species of local seaweed on total gas production and digestibility when added to cattle diets. Methane reducing candidate species will be cultured at Moss Landing Marine Labs to determine optimal culture conditions and scalability to be used as a feed additive for ruminant livestock. The most promising seaweed species will be tested on dairy cattle to determine the whole-animal effect on digestion and methane emissions.

This project will provide some of the first information for California farmers and policymakers on the potential for seaweed as a feed additive for cattle to reduce overall methane emissions in the state.

Principal Investigators
profile photo of Luke Gardner Luke Gardner
University of California, San Diego, Scripps Institution of Oceanography
Co-principal Investigators
Scott Hamilton
Moss Landing Marine Laboratories / San Jose State University
Stacey Gunter
United States Department of Agriculture (USDA)
Michael Graham
Moss Landing Marine Laboratories / San Jose State University
Kenneth Kalscheur
United States Department of Agriculture (USDA)

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