Journal d'écosystème et d'écographie

Abstrait

Encased in Sediments, Edna Reconstructs the Ecosystem History of One of Europe?s most Polluted Seas

David Coll

The Anthropocene is distinguished by dramatic ecosystem changes caused by human activity. Different geochemical and paleontological proxies can be used to assess the impact of these activities. However, each of these proxies provides only a sliver of an understanding of the effects of anthropogenic impacts. It is extremely difficult to reconstruct the state of ecosystems from the preindustrial period to the present day, taking into account all biological components ranging from prokaryotes to multicellular eukaryotes. We used sedimentary ancient DNA (sedaDNA) archives that included all trophic levels of biodiversity to reconstruct the two-century natural history of Bagnoli-Coroglio (Gulf of Pozzuoli, Tyrrhenian Sea), one of Europe’s most polluted marine-coastal sites. Until the beginning of the year, the site was distinguished by seagrass meadows and a high eukaryotic diversity. The ecosystem then underwent a complete transformation, with seagrasses and associated fauna, as well as diverse groups of planktonic and benthic protists, being replaced by a low diversity biota dominated by dinophyceans and infaunal metazoan species. The sedaDNA analysis revealed a five-phase evolution of the area, with changes appearing as a result of a multi-level cascade effect of industrial activities, urbanisation, water circulation, and landuse changes. The sedaDNA allowed us to infer reference conditions that must be considered when implementing restoration actions.