Geochemical properties of blue carbon sediments through an elevation gradient: study of an anthropogenically impacted coastal lagoon
Anthony Grey | Ricardo Costeira | Emmaline Lorenzo| Sean O’Kane| Margaret V. McCaul | Tim McCarthy | Sean F. Jordan | Christopher C. R. Allen | Brian P. Kelleher
School of Chemical Sciences

Global research is showing that coastal blue carbon ecosystems such as mangroves, tidal and salt marshes, and seagrasses are vulnerable to climate change.  They are subject to threats including accelerated sea-level rise and prolonged periods of drought. Furthermore, direct man-made impacts present immediate threats through deterioration of coastal water quality, land reclamation, long-term impact to sediment biogeochemical cycling. These threats will invariably alter the future efficacy of carbon capture processes. It is imperative that currently existing blue carbon habitats be protected. 

Knowledge of underlying biogeochemical, physical and hydrological interactions occurring in functioning blue carbon habitats is essential for developing strategies to mitigate threats, and promote conditions to optimise C sequestration/storage.

This study was performed in an anthropogenically impacted blue carbon habitat on Bull Island, Dublin Bay. We determined the quantity and distributions of bulk geochemical characteristics in sediments through the elevation gradient, including total organic carbon (TOC), total nitrogen (TN), total metals, silt, clay, and also, 16 individual polyaromatic hydrocarbon’s (PAH’s) as an indication of anthropogenic input.