Laboratory-based assessment of polycyclic aromatic hydrocarbon uptake in a Southwestern Atlantic endemic coral

Coral reefs are vital ecosystems that support marine biodiversity and provide essential services to coastal economies. However, they are increasingly threatened by different contaminants, such as polycyclic aromatic hydrocarbons (PAHs), toxic compounds mainly derived from petroleum activities and the combustion of organic matter. This study evaluated the acute accumulation of these contaminants in the endemic Brazilian coral Mussismilia hispida, collected from the Marine Protected Area Costa dos Corais (MPACC) and experimentally exposed to three concentrations (50, 150, and 300 μg L^-1) of the eight priority PAHs under controlled laboratory conditions. PAHs concentrations were analyzed in seawater, coral tissues, and skeletons using gas chromatography coupled with mass spectrometry (GC/MS). Concentrations of total PAHs ranged from 3.83 μg L^-1 to 141.7 μg L^-1, 96.2 μg g^-1 to 329.1 μg g^-1, 48.9 μg g^-1 to 237.9 μg g^-1 in seawater, tissues, and skeleton, respectively. The results revealed a clear pattern of dose-dependent accumulation, with coral tissues exhibiting higher PAHs retention than skeletons. In seawater samples, PAH concentrations declined sharply over time, suggesting rapid absorption by corals or degradation through physical-chemical processes. The detection of PAHs even in control groups (tissue and skeleton) indicates potential prior environmental exposure. Overall, M. hispida demonstrated a strong capacity to bioaccumulate PAHs, underscoring its vulnerability and value as a sentinel species for monitoring contamination in tropical reef ecosystems, particularly in regions affected by oil exploration and production.