Macroalgal diversity in acidified environment of Castello Aragonese (Ischia) through DNA barcoding

The acidification of the ocean is one of the most serious threats to the marine ecosystem caused by human activity. Carbon dioxide emissions resulting from anthropogenic sources are partially absorbed by the oceans, leading to an increased water acidity with often harmful effects on marine organisms. The volcanic vents around the Castello Aragonese (Ischia) are characterized by high emissions of carbon dioxide. These vents create a natural acidity gradient in the surrounding waters and thus represent a natural laboratory for understanding the phenomenon of acidification and its effects on marine biodiversity. They serve as a natural laboratory, illustrating what the ocean might look like in a future scenario of increased water acidity. An accurate estimate of the number of photosynthetic species along the acidity gradient is essential for understanding how pH will impact algal diversity and, consequently, marine ecosystems. Thus, this study aims to investigate the macroalgal biodiversity in the surrounding areas of the Castello Aragonese through an integrated approach combining morphological and molecular analyses, with the objective of accurately identifying photosynthetic organisms and assessing their distribution in relation to pH levels.