Coupling biogeochemical analysis, environmental DNA and ecological network analysis of sediment cores to reconstruct environmental history and ecosystem changes in Posidonia oceanica meadows.

POSIDONIArXiv combines multiple disciplines to reconstruct ecosystem processes, dynamics and change through time in Posidonia oceanica meadows in Spain.

P. oceanica is an iconic seagrass in the Mediterranean Basin, forming extensive meadows and dense mats which work to stabilise sediments and form a millenary sedimentary archive while providing habitat for an abundance of marine life.

P. oceanica meadows contribute to global change mitigation and adaptation by sequestering pollutants including CO2, and reducing coastal erosion, while enhancing biodiversity by providing habitat and breeding areas for marine life including commercial species.

However, seagrasses in general and P. oceanica in particular, are in decline due to anthropogenic disturbances such as climate change, pollution and land-use change.

These meadows sustain the livelihoods of coastal populations and are located in coastal areas throughout the Mediterranean.

In particular, P. oceanica inhabits sheltered embayments that also constitute key areas of settlement by ancient civilisations until present.

POSIDONIArXiv combines environmental DNA, biogeochemical analysis and ecological network analysis to understand the historical changes in P.oceanica meadows.

Firstly, sediment cores will collected at sites of high and low anthropogenic disturbance and biogeochemical analysis will be conducted to determine key periods of human or natural disturbance. This will inform sampling and eDNA analysis to reconstructed historical changes in biodiversity at these sites.

Furthermore, the eDNA data will be used for ecological network analysis over millennia timescales to understand biodiversity change and identify mechanisms of resilience in this environment.

Overall, POSIDONIArXiv will strengthen management and restoration targets for P.oceanica environments and contribute key knowledge to historical reconstructions of whole ecosystems.