How Seaweed Airs Cattle Carbon Grievances

By Melanie Stern

Supply chains relying on agriculture are challenged by an escalating carbon footprint on land, sea and in the air we breathe. Finding solutions to diminish the ecological impact and reverse the trend are top of mind not only for economic leaders, government legislators and environmental activists, but also CPOs and suppliers.

Sheer numbers dictate a compelling story for change. A 2022 Intergovernmental Panel on Climate Change (IPCC) assessment indicated human-driven methane emissions emanate nearly 45 percent of net warming, 32 percent of which come from livestock flatulence, belches and manure. The U.S. has 94 million cows — each one, on average, burps 380 pounds of greenhouse gas per year.

“Livestock plays a vital role in feeding the billions of people who inhabit the planet,” said Ermias Kebreab, professor and Sesnon endowed chair of the department of animal science at University of California, Davis. Since much of livestock’s methane emissions come from the animal itself, nutrition plays a big role in finding solutions, Kebreab said of his studies on seaweed. He and UC Davis research partner Ph.D. graduate student Breanna Roque continue their work on red seaweed as a viable solution for removing methane emissions produced by cattle.

Options in removing methane emissions from cattle are to bypass the methane process or provide a viable place to store or convert the methane emitted, without causing harm to the animal, humans or the environment.

Because methane emissions are a growing concern worldwide, an increase in research and development to provide solutions to the cattle carbon footprint show promise.

Farming Ecological Footprint Through Feed

The digestive process of cows is simple yet complex. Their stomachs have four compartments: rumen, reticulum, omasum and abomasum. As the cattle feeds on vegetation, the digestion begins and moves through the compartments, each with a specific purpose.

The rumen compartment houses many microbes engaging fermentation and breakdown of the feed ingested, generating nutrients. Nonutilized byproducts leftover from the process, including hydrogen and carbon dioxide, immerse with methanogens — methane-producing microbes, forming methane. With nowhere else to go, cows’ natural response to the methane is to “air” it out, creating an environmental conundrum.

Agricultural and environmental communities have considered the influence of the feed itself. The Institute of Agriculture and Natural Resources at University of Nebraska, Lincoln has found that grain-fed cattle emit less methane compared to grass-fed cattle.

But many recent studies have shown dairy and beef farmers promising solutions for reducing cattle’s carbon output by circumventing their natural digestive process. Asparagopsis taxiformis, known as red seaweed, is the subject of many large-scale farm trials worldwide. Though the findings on red seaweed’s efficacy in methane reduction varied between studies, the merits of its use and associated challenges have gleaned the interest of agriculture-based producers and suppliers.

Hawaii-based Symbrosia, a cleantech startup, and Australia’s Commonwealth Scientific and Industrial Research Organization, are each developing red seaweed supply chains for commercial adoption, have reported cattle methane reductions of more than 90 percent when their feed is supplemented with red seaweed (equal to less than one percent of daily diet). Tim Flannery, Ph.D., professor, scientist and researcher at the University of Melbourne, Australia, studied tropically-grown red seaweed for cattle application and realized methane reduction results of 98 percent.