Kelp for Climate: A Sustainable Seafood Future
Seaweed in the midwest is known as the slimy strands that wrap around your legs when you jump into the lake on a hot summer’s day. While in Japan, seaweed is a treasured component of the cuisine, used in soups, sushi rolls, or onigiri. Throughout the world, seaweed is showing increasing promise as a key solution to climate change. This ocean organism is capable of restoring ocean ecosystems, sequestering carbon, creating jobs, capturing nutrient runoff, producing bioplastics, and more.
Photo by Shane Stagner on Unsplash
For thousands of years, humans have harnessed seaweed in extraordinary ways. In the US, regenerative ocean farming has been a way of life in the Pacific Northwest and Alaska for centuries, where indigenous communities valued kelp as subsistence and utilized it in fishing, hunting, food preparation, and storage. Learning from these communities, kelp farming is now a growing industry worldwide. But native populations of kelp can’t provide sufficient quantities to positively contribute to climate change alleviation on a global scale, so how are we growing more?
THE OCEAN AS THE NEW SUSTAINABLE AGRICULTURE FRONTIER
Regenerative ocean farming (ROF) is defined by kelp farming nonprofit, GreenWave, as a “polyculture farming system [that] grows a mix of seaweeds and shellfish [and requires] zero inputs…while sequestering carbon and rebuilding reef ecosystems.” Unlike terrestrial farming, ocean farming takes a “3D” approach, using the entire water column to grow restorative species, giving it a small footprint because of its vertical growth as well as low aesthetic impact, existing entirely underwater.
GreenWave’s system employs an efficient use of space to cultivate seaweed, scallops, and mussels, all of which hang on weighted ropes down into the ocean from buoys. Cages full of oysters and clams hang below on the ocean floor, creating a polyculture where various species grow at the same time and place in imitation of the diversity of natural ecosystems. The seaweed and shellfish don’t need to be fed and can be left to simply grow with sunlight, nutrients, and plankton already in the water.
Photo by Anika Mikkelson on Unsplash
In addition to kelp reforestation and restoration of ocean ecosystems, the kelp-farming industry is capable of capturing enormous amounts of blue carbon and nitrogen. Blue carbon is the carbon stored in coastal and marine ecosystems. Seagrass meadows and kelp forests can store more carbon per unit area than terrestrial forests and are now increasingly recognized for their role in mitigating climate change through atmospheric carbon reduction. Polycultures can have an even greater impact as oysters, clams, and other shellfish are efficient feeders that help remove excess nitrogen from waters by incorporating it into their tissue and shells as they grow. Adult oysters are reportedly able to filter up to 50 gallons of water a day! But, if the oceans continue to become increasingly acidic, these helpful species’ lives are threatened.
KELP FORESTS; CARBON SINKS AND JOB PRODUCERS
Our oceans already absorb nearly 25% of the carbon dioxide we emit into the atmosphere, but excess carbon and nitrogen are causing our oceans to become increasingly acidic. Ocean acidification is accelerated by fossil fuel combustion, forest loss, and urban runoff. This increased acidity is harmful to shellfish as it dissolves their shells and interferes with new shell growth. This then impacts the food web because fish, whales, and sea birds rely on shellfish for food and habitat. Increased ocean acidification also negatively impacts fishermen and other coastal communities that rely on healthy ocean habitats. As waters continue to warm, people like lobstermen who rely on the sea for their income are turning to kelp farming to diversify their income.
Similar to terrestrial forests and plants, marine algae and seaweeds naturally take up carbon dioxide and nutrients like nitrogen and phosphorus. Kelp is one of the fastest-growing plants on earth and can grow as much as 15 feet in a single season and requires no fertilizers, pesticides, freshwater, or arable land. But the benefits of kelp for farmers and our environment don’t stop there. Kelp continues to benefit our food system when it is farmed commercially to grow seaweed for animal feed, fertilizer, bioplastics, and more.
Photo by Alex Blăjan on Unsplash
KELP FOR COWS
As humans, we take antacids to help reduce burps. But have you ever thought about burping cows? They burp — big methane burps. According to the Food and Agriculture Organization of the United Nations, beef cattle and dairy cows are one of the top methane polluters, a greenhouse gas that has more than 80 times the warming power of carbon dioxide over the first 20 years after it reaches the atmosphere. As the world searches for solutions to reduce carbon in the atmosphere, focusing on enteric methane emissions can be critically valuable.
Research shows increasing evidence that small additions of seaweed to animal feed could forcefully reduce livestock’s greenhouse gas impact. A recent study published by the University of California, Davis states that “a bit of seaweed in cattle feed could reduce methane emissions from beef cattle by as much as 82 percent.” More studies are slated to investigate the long-term use of seaweed in animal feed and it will be interesting to see if one day, it is incorporated into animal feed as a standard ingredient.
FROM OCEAN TO LAND; KELP IN FERTILIZER
Kelp is an extremely productive ocean plant and it can help land plants become more productive as well. Over 12,000 species of seaweed have been identified, and many are valuable fertilizers for organic gardens. Studies have shown that the addition of seaweed fertilizers increased enzyme activity as well as enhanced carbon capture during plant growth. More research is needed on kelp fertilizers but it is a promising addition for organic and sustainable agriculture.
Seaweed shows endless promise in contributing to a sustainable future. Its potential to clean up Earth’s oceans, restore biodiversity, and increase the productivity of aquaculture are just a few of the benefits. Seaweed has a long way to go to fulfill those ambitious goals, as the potential for kelp farms has barely been tapped. Investing in practices like regenerative ocean farming creates trickle-down effects because of the incredible versatility of the crop that benefits both the economy and the environment. If we can perfect the cultivation of kelp on ocean farms, the benefits can be shared with industries throughout the world. With the incredible growth rate of kelp, the potential to move the needle on climate change is even more exciting.
