Just a few meters from the access ramp to the Aragonese Castle of Ischia, one can glimpse lots of bubbles leaking out of the seabed, only a few palms deep. Not to be feared, they consist of 95 percent carbon dioxide; their presence is due to the secondary volcanic phenomena to which the island has always been subjected. This natural site because of its uniqueness has become the most studied carbon dioxide emission system in the world, with scholars coming from all continents, since it appeared in 2008 in the prestigious journal Nature An article with the first studies conducted by researchers at the Zoological Station “A.Dohrn” in Ischia.
But what is so interesting about this site?
These natural emissions of carbon dioxide from the seabed easily acidify the water mass of the 2,000 m² of affected area, bringing the pH (chemical indicator of acidity) from its normal value of 8 to about 6. In areas of intense emissive activity there is a massive reduction in marine biodiversity, both plant and animal. Posidonia oceanica meadows become depleted of their own communities of calcareous organisms, which cannot withstand such an acidic environment, with obvious consequences for the entire ecosystem. Starting with so many fish that can no longer find their livelihood, instead favoring a few resilient species. In areas of higher emission, and therefore more acidic, a 74 percent reduction in species was observed adjacent to the Aragonese Castle in areas of normal pH.
Why so much interest from scientists in such an unusual natural phenomenon?
The increase on a global scale in the concentration of carbon dioxide in the air leads to the so-called phenomenon of acidification of the seas, resulting in very worrying predictions for 2100.
Here scholars have at their disposal a true natural laboratory for predicting what our seas might look like in the not-too-distant future, an open window to the future.