The Regenerative Power of Seaweed

The tending of underwater plants for human uses does not need to be destructive — in fact, it can be just the opposite. On May 6, a panel of environmental experts discussed regenerative aquaculture in the first of a series of four webinar discussions on the topic by AltaSea at the Port of Los Angeles.

Regeneration improves ecosystems, typically done by using seaweeds. These seaweeds are grown as part of an aquaculture system but support the whole system.

“When you have lots of parts in the system that are being fed by what you’re doing, then the whole thing becomes more resilient to climate change, to any kind of small or large disaster” said Dr. Janet E. Kübler, who works in the biology department at California State University Northridge.

Just as the land has agriculture, the ocean has the seaweed industry. More than 99% of the industry is dominated by Asian countries, said Dr. Charles Yarish, professor of ecology and evolutionary biology at the University of Connecticut. However, seaweed’s many uses have caught the attention of western countries within the past decade. These include food, feed, fertilizers, medicine, cosmetics, textile, paper, leather and biofuels.

While other species are struggling because of climate change, seaweed is doing fine, Kübler said.

“I have spent decades studying how seaweeds respond to climate change, how they’re affected by climate change,” Kübler said. “The answer is: not that much. Except seaweeds generally thrive in a wide range of conditions and they can adjust their physiology to changes in their environment around them. Many seaweed species are actually pretty good at compensating for things that people do in coastal waters.”

For example, if people put nutrients into coastal waters, the seaweeds will use them to grow. When carbon dioxide is put into the water, the seaweeds benefit from it.

“In most parts of the world right now, seaweed abundance is increasing,” Kübler said. “Seaweeds are doing better under these conditions.”

There are exceptions, such as in places where the upper thermal limit has forced seaweeds out. And in some parts of California, diseases from other species have prevented kelp from returning to their natural habitat. But in general, seaweeds provide a solution to a current ecological problem — providing more food in a less ecologically demanding way.

Yarish said that seaweed is very nutritious, and some are high in vitamin C, while others have more protein than steak on a weight basis.

“In the next year or two years, you’re going to see more of the plant-based products that are coming to market that are going to include seaweed,” Yarish said.

Seaweed can also help reduce carbon dioxide, as they incorporate it into their biomass.

Yarish has grown seaweed in the East River in New York City, including kelp. Along the river’s path to the Atlantic Ocean, there was a nitrogen gradient that caused major problems, because there were too many nutrients. In addition, ocean acidification was also a problem, and fish and shellfish were dying.

“We developed a solution: grow seaweeds, grow shellfish, grow them together, and you are using organisms that are extracting nutrients from the water,” Yarish said. “We call this nutrient bio-extraction.”

The experiment was held for a full year. The seaweeds saw tremendous growth, and the nutrients were reduced, removing both nitrogen and carbon dioxide. Not only that, the nitrogen and carbon can be recycled, and used on land.

“This was such a simple system, it caught the attention of the U.S. EPA,” Yarish said. “They gave us a shoutout about sea farming … saying this may be a valuable tool for coastal managers.”

In addition to absorbing excess nutrients, seaweeds make compounds that they put back into the ecosystem, Kübler said. These compounds feed microscopic animals in the water, contributing to the food web.

“They give back to the ecosystem, and that’s regeneration,” Kübler said.

Finian Makepeace, co-founder of environmental group Kiss the Ground, argued that humanity needs to move out of the mindset of conserving what is left of the environment, and instead move into the mindset of regeneration.

“At the very core of it is a fundamental question of how we’re viewing what humans are going to contribute to in the coming years,” Makepeace said. “Are we moving from a force that is degenerating our land, and our oceans, or are we going to be a force that’s regenerating it?”

Makepeace said that when people simply blame environmental problems on climate change without diving deeper into them, they miss out on what humans can do as a contribution for good. Every year, 32 million acres of land undergoes desertification, meaning it becomes so destroyed it can no longer be farmed.

Makepeace said there is too much carbon dioxide in the atmosphere, but that carbon is the solution to building back a functioning soil ecosystem. He argued that similar solutions can be used for aquaculture — such as planting seaweeds to bring back keystone organisms that may have left certain areas.

“Humans have the wherewithal to think about what we are doing to practically help this ecosystem come back to its highest functioning state,” Makepeace said.

The reason why the regenerative aquaculture industry has not had more success is because there is still a lot of caution on doing it correctly.

“This kind of conversation that we’re having about what is good for the ecosystem or not good for the ecosystem is being considered at many levels of government,” Kübler said.

Much of the worry comes from the way fish farming used to be done, even though such methods are rarely used today. Fish were overfed, kept in shallow water, and spread diseases to other fish.

“In current practices, we’ve learned a lot of the ills of the wild west mentality of aquaculture, where you really degraded the environment,” Yarish said.

While coastal regulators were not as careful in the past, they have changed their standards.

“The most successful operations in fish aquaculture are the ones that are the cleanest,” Yarish said.