A new study published in the Marine Environmental Research journal reveals that a population of brain corals living near the main island of the Alcatrazes Archipelago Wildlife Refuge (REVIS) in Brazil has the ability to retain about 20 tons of carbon per year.
This finding indicates that beyond serving as a marine conservation unit, coral populations like the one in the REVIS can also act as a potent carbon sink that can play a meaningful role in global climate change mitigation efforts.
The study is part of the Alcatrazes Sea Project, a collaborative initiative between UNIFESP, the Chico Mendes Institute for Biodiversity Conservation, and Petrobras.
In it, researchers note that while tropical corals can emit more CO2 than they absorb due to the high respiration rate of the organisms living in these warmer ecosystems, subtropical corals like the ones in the REVIS are operating in a way that enables them to absorb more atmospheric carbon than they emit.
Namely, the analyzed specimens of brain coral (Mussismilia hispida) have rocky parts that are covered in CO2-absorbing microalgae, and they do not form large reefs, which might be explained by the frequent storms in the region or the fact that they haven’t lived in the area long enough to evolve into broader ecosystems.
These two factors, according to the research team, are what enable the great carbon storage capacity in these marine species.
By locking in carbon through mineralization, corals have the ability to provide durable CO2 storage that can span for centuries or millennia.
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To assess the exact amount of CO2 stored in these corals, the researchers performed CT scan tests, evaluating data accumulated between 2018 and 2023 and factoring in the area of seabed occupied by this species.
The calculations showed that on an annual basis, these corals can take in approximately 20 tons of CO2, a volume matching the carbon emissions from burning 324,000 liters of gasoline.
This highlights that coral populations could be a valuable tool not only for protecting marine ecosystems but also for restoring the climate.
Read more: Carbon Sinks 101: Natural vs. Man-Made Carbon Storage Solutions
