Seaweed beyond sushi
Anybody who loves sushi could gush about the importance of the edible seaweed species by the name of Nori in creating the dish. Meanwhile, a team of UCSB researchers are looking into how seaweed and its varying species can be used to mitigate carbon emission.
Seaweed, as the plants of the ocean, behave similarly to their cousins on land: taking in carbon dioxide and producing oxygen. This similarity is precisely why some scientists are turning to seaweed for mitigating greenhouse gas emissions.
Halley E. Froehlich, a marine ecology professor at UCSB, and three other researchers of UCSB-affiliate National Center for Ecological Analysis and Synthesis analyzed what mitigation efforts involving seaweed would look like, specifically in aquaculture, the cultivation of fish and other aquatic species.
Dr. Froehlich’s academic background includes more than a decade of studying animal biology, marine ecology and fishery sciences. The researcher, however, was introduced to marine life before her embarkment of higher education.
“My grandfather was an albacore fisherman,” Dr. Froehlich told the News-Press. “It’s pretty great to be able to have a conversation with my granddad about how the fish are doing.”
And it was this study about how the fish are doing that got Dr. Froehlich and her team to study seaweeds.
She and Ben Halpern, another UCSB professor, were conducting research on aquaculture production and its role in the climate, when the pair noticed that seaweeds could play a role in mitigating the carbon emission of this very aquaculture production.
The pair and their team analyzed this potential role of seaweed, and the peer-reviewed journal Current Biology recently published her team’s findings.
Dr. Froehlich told the News-Press that seaweeds “capture the carbon…and can grow and store carbon in a way that takes it out of the atmosphere.”
The same could be said about plants on land. There is, however, a major difference between seaweed and land plants.
According to Dr. Froehlich, plants can transfer the carbon dioxide into the ground through their roots, but seaweed must store the gas within them. So then in order to prevent the carbon dioxide from escaping back into the atmosphere, the seaweed must not be consumed.
“Currently, seaweeds are cultured primarily for food, medicine, cosmetics and bioenergy…” write the researchers.
For a seaweed offsetting effect to occur seaweeds must be essentially buried.
“Wild seaweeds may sequester significant amounts of carbon in the oceans” if the seaweeds are exported to the ocean at 1000 meters or deeper, write the authors, who hold an assumption that technology “would facilitate and potentially optimize the offshore export process, specifically depositing seaweed in the deep ocean where the material is mineralized to remain for hundreds to thousands of years.”
When asked about the burial of seaweed underground instead of under the ocean, Dr. Froehlich said, “Direct burial would be problematic because you would have to disturb habitat and likely emit additional carbon dioxide in the process.”
While talking with the News-Press, Dr. Froehlich was very conscious of the chain of events in our actions.
“Everything we do can have a chain of events resulting in a higher concentration of carbon dioxide going in the atmosphere,” she said.
For the seaweed to offset as much carbon dioxide as possible, location plays a key role.
“Ideally, (you bury) near where you’re farming,” said Dr. Froehlich.
“Specifically, 132 countries have likely suitable nutrient levels (for seaweed production), but only 37 are currently producing,” write the researchers. “Notably, several large greenhouse gas emitters, such as the United States, have no measurable seaweed aquaculture production.”
According to the study, the U.S. could theoretically produce seaweed for the purposes of offsetting carbon emission. The researchers found that both west and east coasts of the U.S. — where nutrients are available for seaweed growth — are native ranges for wild seaweeds.