Probably the most critical local weather change-related threats to shellfish is attributable to rising ranges of carbon dioxide (CO₂) within the Earth’s environment. As CO₂ makes its way into the oceans, chemical reactions occur that lower pH and create ocean acidification. For the previous twenty years, local weather change analysis has proven that rising CO₂ ranges in floor waters threaten shellfish that require higher-pH waters to develop and survive — an alarming discovery in coastal zones the place extra sources of acidity can additional cut back pH and sluggish sure species’ shell formation.
However researchers might have realized that kelp may assist ameliorate this phenomenon.
A Stony Brook College-led examine titled “Kelp (Saccharina latissima) mitigates coastal ocean acidification and increases the growth of North Atlantic bivalves in lab experiments and on an oyster farm,” reveals that harvesting kelp could also be a brand new approach to assist preserve bivalves comparable to clams and oysters wholesome and extra considerable. The examine, led by Christopher Gobler, endowed chair of coastal ecology and conservation at Stony Brook’s College of Marine and Atmospheric Sciences (SoMAS), and colleagues was revealed within the journal Frontiers in Marine Science.
Gobler and his crew carried out six experiments to evaluate the results of elevated CO₂ and the presence of kelp on the expansion charges of three totally different bivalve species: Jap oysters, blue mussels and arduous clams. In every of the experiments, kelp cultivation considerably diminished acidification. The analysis was supplemented with a subject experiment at Nice Gun Oysters aquaculture farm in East Moriches, New York.
“When people think about climate change, they’re most apt to think the weather is getting warmer, temperature is getting hotter, and that there are more heat waves, but a less well-known symptom of climate change has to do with our oceans,” mentioned Gobler.
The examine demonstrated that the deployment of kelp on an oyster farm combats ocean acidification and due to this fact helps shield bivalves. The method can also have extra ecosystem and aquaculture advantages, together with the sequestration and extraction of carbon and nitrogen, and safety in opposition to dangerous algae blooms. Gobler mentioned acidification is detrimental to coral reefs and various kinds of algae, in addition to species that want calcium carbonate to make their shells, together with bivalves.
“This also affects lobsters and crabs,” mentioned Gobler. “Making shells becomes more and more difficult as the levels of CO₂ increase in our atmosphere and in our oceans.”
The analysis crew discovered that in a one-month deployment, oysters that had been surrounded by kelp loved higher-pH water and grew considerably quicker than particular person shellfish situated farther away the place the pH of the water was decrease.
Mike Doall, affiliate director for bivalve restoration at SoMAS and a member of the analysis crew, mentioned kelp could be a helpful and worthwhile choice for oyster farmers.
“I’m an oyster farmer and I started thinking about kelp 10 years ago when I was looking for ways to diversify my business,” mentioned Doall. “I met somebody who was growing kelp in Maine and my first reaction was one of surprise. I had no idea why they were growing it or what they were going to do with it. But the more I looked into it and the more I researched it, I began to realise that this is the perfect companion product of oysters.”
Doall defined that kelp has an reverse rising season from oysters. Particularly, farmers can divert assets from oysters within the heat months to kelp within the colder months. What’s extra, kelp may be built-in vertically with oysters and different shellfish, which implies that farmers can diversify with out having to exchange one crop for an additional out within the ocean.
General, the analysis clearly exhibits that the cultivation of kelp constitutes an environmentally pleasant technique of defending shellfisheries in opposition to current and future ocean acidification and different coastal stressors.
“We’ve helped grow kelp on 10 oyster farms across New York since 2018, and more and more aquaculturists have been hoping to incorporate kelp into their farms,” mentioned Doall. “In addition to providing crop diversification and additive revenue streams, the ability of kelp to fight ocean acidification gives these oyster farmers one more reason to add kelp as a second crop.”
Doall described kelp and seaweeds as, “unlike anything else you can grow on land and water.”
“There are zero inputs,” he mentioned. “You don’t have to fertilise them. You don’t have to feed them. They don’t require pesticides or insecticides. They suck up carbon dioxide, and they also suck up nitrogen, which is one of the major water-quality problems facing Long Island and other coastal areas. The result is a net extraction from the environment. So there are a lot of really good environmental and economic reasons to grow kelp.”
The current examine builds on earlier analysis by the identical SoMAS group demonstrating that kelp has the power to discourage the depth of dangerous algal blooms, one other environmental risk to shellfish aquaculture. That examine was revealed within the journal Dangerous Algae in 2021.
Each Gobler and Doall mentioned the findings may have highly effective implications for oyster farming in coastal zones on Lengthy Island and world wide.
“We have been witnessing coastal ocean acidification for years and have documented its ability to slow the growth of, and even kill off, shellfish,” mentioned Gobler. “We began growing kelp on oyster farms to simply expand aquaculture regionally. After seeing its ability to rapidly take up CO₂ and improve low pH conditions, we knew it had the potential to benefit shellfish experiencing acidification. And while showing that in the lab was exciting, being able to improve the growth of oysters on an oyster farm experiencing coastal acidification proves this approach can have very broad applications.”