A new study shows oyster farming may help fight climate change by removing more carbon from the ocean than it adds. Oysters boost photosynthesis in surrounding waters, making the ecosystem more effective at absorbing CO₂.
New study suggests that oyster farming might be doing more than just providing food. It could also help reduce carbon in the ocean and fight climate change. Scientists are looking into aquaculture, the farming of fish and shellfish in water, as a way to provide food and lower carbon levels in the environment.
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But results show that sometimes it's unclear if these methods help or add more carbon. Oyster farming is one example where the results are not so clear. Earlier studies suggested that oysters add carbon to the ocean when they build their shells and breathe. Now, new research shows there might be more to this story.
A recent study published in the Proceedings of the National Academy of Sciences found that oyster farming might actually remove more carbon from the ocean than it releases. The researchers say this is mainly because of the oysters' feeding habits and how they change the water's chemistry.
How the Study Worked
Experts ran a 120-day experiment using large outdoor tanks filled with Pacific oysters. The team tested different oyster densities: some tanks had more oysters, others fewer, and one group had none. The researchers measured:
* Different types of carbon in the water
* How much carbon dioxide (CO₂) moved between the water and air
* And the amount of chlorophyll-a, which shows how much phytoplankton, tiny ocean plants, are present.
These phytoplankton help absorb CO₂ through photosynthesis.
What They Found
The results were surprising. The oysters trapped carbon in their shells and the ecosystem around them actually absorbed 2.39 times more carbon through biological processes like photosynthesis than what was stored in the shells themselves.
The water in the oyster tanks became more alkaline and more autotrophic, meaning it supported more plant growth and was better at taking in CO₂ from the air. This also helped reduce ocean acidification, which is a big concern because high CO₂ levels are making the ocean more acidic.
Researchers said that the overall ecosystem behaves differently. On a larger scale, the positive impact of photosynthesis is the key factor.
The researchers found that although individual oysters release carbon, at the ecosystem level, increased photosynthesis helps remove more carbon from the environment. Tanks that had a moderate number of oysters captured the most carbon because they maintained a healthy balance of phytoplankton. However, when there were too many oysters, the phytoplankton population decreased, which reduced photosynthesis and limited the system's capacity to absorb carbon.
In simpler terms, oysters eat the tiny phytoplankton in the water. Too many oysters eat too much, and not enough phytoplankton are left to absorb carbon through photosynthesis.
Why Is It Important
This study shows that oyster farming could serve two important purposes: feeding people with sustainable seafood and removing carbon from the environment. The researchers also warned that more studies are needed, especially in open coastal waters, where things are more complex than in controlled tanks. Oyster aquaculture could play a helpful role in addressing both climate change and the global food challenge.
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