Seaweed – the solution to revive the coastal ‘dead zone’

Profitability for seaweed farms is something to consider to promote them as a municipal and agricultural waste treatment solution.

The key to the success of seaweed farming is its growing commercial potential. Illustration: sciencefriday. A new study argues that growing a sufficient number of green seaweeds can help reduce pollution, absorbing most of the harmful waste. The study’s co-author, Phoebe Racine, said the thesis was just an early idea and implementation would take time, but given the lack of progress in other aspects, “there was no other option.” in addition to considering alternative methods”. Racine, a researcher at the University of California at Santa Barbara, says growing a variety of seaweed species in less than 1 percent of the Gulf of Mexico’s waters could help the United States meet pollution reduction goals that are already out of reach. . She and her colleagues mapped the suitable area for seaweed cultivation in the Gulf, and the suitable area could be more than 38,500 square kilometers. The Gulf of Mexico is being choked with agricultural and municipal waste. In May 2019, the Mississippi River discharged an average of more than 5,000 tons of nitrates and 800 tons of phosphorus into the Gulf of Mexico, the highest levels in 40 years. These excess nutrients from farm fertilizers and animal waste in the Midwest robs the oceans of oxygen off the coasts of Louisiana, Mississippi, and Texas, fueling toxic algae blooms that have led to the so-called “dead zone”. Eutrophication (also known as eutrophication) is when there are too many nutrients in the pond/lake such as nitrate, phosphorus, which exceed the self-regulating capacity of the pond/lake, causing dense growth of plant and animal death due to lack of oxygen. To environmental experts, this problem seems intractable. Called eutrophication, dead zones are proliferating all over the world. There are more than 700 coastal areas worldwide that are “dead zones” or negatively impacted by currents. While the United States bears the bulk of agricultural waste, municipal wastewater is the main culprit in South America, Asia, and Africa. Annually, they cause economic losses of $3.4 billion in Europe and the United States alone by affecting tourism and fishing resources; while reducing property values, water treatment and adverse health effects. Over the past 10 years, 85 communities in the United States have spent a total of more than $1 billion to prevent or treat toxic algal blooms. Among the hardest hit areas is at the mouth of the Mississippi River, where the continued discharge of domestic waste from the heart of the United States has destroyed the local seafood and tourism industries. The Mississippi River empties into the Gulf of Mexico, carrying fertilizer and livestock waste from Midwestern farms. Photo: Bloomberg. Growing seaweed is considered as one of the green solutions to solve this problem. Seaweed farming dates back to 1,700 years ago in China. Today, countries like Indonesia and the Philippines, along with China and South Korea, lead the world in this area. In South Korea, where aquaculture has grown by 300% in the past 30 years, an intensive effort has proven its usefulness as a waste reduction tool. According to one study, farms that grow three major seaweed species and two shellfish species (all filter feeds without additional feed) accounted for 5.7% of carbon dioxide and 8.6% of carbon dioxide emissions. nitrogen emissions from all wastewater treatment plants in Korea. The key to the success of seaweed farming is its growing commercial potential. These aquatic plants can absorb excess nitrogen and phosphorus, turning it not only into food for humans, but also expanding a range of other commercial uses. The most commonly grown seaweeds include red or brown algae or algae. Some are used to make culinary thickeners or jellies for culturing bacteria in the lab. Others are dried into sheets for sushi rolls. While sugar kelp can be used as a sweetener, kelp is also used in toothpaste, shampoo, frozen foods, and even pharmaceuticals. Making seaweed farms profitable will be an important consideration to promote them as an agricultural and municipal waste treatment solution. Asia currently has a very strong demand for seaweed. Human consumption, which includes everything from sushi rolls to broths to salads, is the largest market for harvested seaweed. But growing demand can also be seen in the cosmetic and fertilizer industries, as well as aquafeeds. However, mass aquaculture faces a number of significant obstacles, particularly its labor-intensive nature. Globally, the demand for seaweed is forecast to double to $30 billion by 2025. However, in the United States, the seaweed market is relatively small. Gretchen Grebe, an aquaculture scientist at the Marine Biology Laboratory in Woods Hole, Massachusetts, says seaweed farming in the US is largely “in the R&D phase.” “Using seaweed farming to remediate any large amounts of nutrient pollution would require significant expansion — the current scale of farming wouldn’t even matter,” says Grebe. In the United States, states have different regulations regarding aquaculture licensing. While it’s relatively easy to get a seaweed farm permit in Maine and Alaska, in California it requires meeting a stack of overlapping regulations. Bailey Moritz, Program Manager of the World Wildlife Fund, said: “Offshore activities hold promise. Our goal is to see seaweed growth that will have meaningful impacts [đối với sự suy giảm chất dinh dưỡng], and scale is needed for that.” But large-scale offshore seaweed farming is still at least a decade away from taking place in the US, and only when biofuels, bioplastics and animal feed are generated enough. need. Seaweed holds great promise, Grebe said, but scientists are quick to point out that the main driver is the imperative to reduce watershed waste inputs. “We are asking a lot of seaweed farmers to treat the nutritional waste that we dump into the Gulf,” she concludes.