Coral injuries observed at Mesophotic Reefs after the Deepwater Horizon oil discharge

摘要: Abstract Pathologies in over 400 octocoral and antipatharian colonies were quantified the aftermath of DWH oil discharge. Observations made September 2011 at water depths 65–75 m Pinnacle Reef trend area offshore from Mississippi Alabama, Gulf Mexico, using a digital macro camera deployed an ROV to examine coral populations for injury two principal sites: Alabama Alps (AAR) Roughtongue (RTR). Taxa observed exhibit included gorgonian octocorals Hypnogorgia pendula , Bebryce spp., Thesea nivea Swiftia exserta Antipathes atlantica, sea whips Stichopathes sp., Ellisella barbadensis . The most common type was biofilm with clumped or flake-like appearance covering sea-fan branches. Extreme injuries characterized by bare skeletons, broken missing Comparing results previous photo surveys same study sites between 1997 1999, we found significantly more occurrences among taxa growth forms >0.5 m. We hypothesize that Tropical Storm Bonnie facilitated accelerated mixing process dispersant-treated hydrocarbons into column, resulting harmful contact mesophotic depths. Analysis total polycyclic aromatic hydrocarbon (tPAH) concentrations sediments AAR RTR levels elevated above pre-discharge values, but orders magnitude below toxicity thresholds established fauna estuarine sediments. tPAH measured echinoderm tissue samples detectable (mean values ranged 51 345 ppb); however, bioeffect do not currently exist which evaluate potential harm these may cause. Our findings indicate have resulted acute, isolated event rather than ongoing natural processes.