Chukchi Sea Environmental Assessment and Drilling Discharge Monitoring: Benthic Community Assessment and Toxicology
Client: Shell Exploration and Production
EcoAnalysts conducted a baseline benthic community assessment and post-drilling monitoring study in the Chukchi Sea Lease Area for Shell Exploration and Production. Primary objectives were to analyze benthic communities within the lease area before and after drilling to determine if a measurable impact on the benthos occurred that could be attributable to drilling activities, the level of such impact and its spatial effect on community structure, and the extent and timeline of recovery potential that can be expected at effected locations.
EcoAnalysts scientists were involved in every phase of the community assessment program, including field collection of samples, sample sorting, specimen taxonomy, statistical analysis, final reporting and presentation of results to the client. More than 350 benthic samples were collected for the baseline and post-drilling surveys. In addition to analyzing standard biodiversity measures (taxa richness, abundance, evenness, and diversity), multivariate cluster analyses were performed across samples and sampling events to compare spatial and temporal similarities between communities. A detailed photographic benthic community atlas was also created to catalogue collected species and provide information related to habitat, food preferences and position within the tropic food web.
Additionally, EcoAnalysts conducted a study focused on the evaluation of shipboard discharges for compliance with national discharge guidance following the National Pollutant Discharge Elimination System (NPDES) for Oil and Gas Exploration Facilities on the Outer Continental Shelf (OCS) in the Chukchi Sea, Alaska for Shell Exploration and Production.
A series of rapid screening and chronic toxicity tests were conducted with selected discharges collected from remote locations with stringent 72-hour holding time requirements for sample testing. EcoAnalysts scientists helped develop the testing program by selection and implementation of the rapid screening test, and by conducting additional studies to examine sample holding time and renewal frequency of discharge samples prior to the start of compliance testing. In total, over 100 toxicity tests were conducted during the 3-month monitoring season and all regulatory deadlines for report submittal were met. In addition, samples eliciting a toxic response were further investigated using toxicity identification evaluation (TIE) procedures to identify the cause of any observed toxicity. The TIE process identified a particular suite of compounds were likely responsible for the observed toxicity.
EcoAnalysts personnel presented the results of these studies to the client and the regulatory agency responsible for permit compliance. The results of the testing program may help to inform future permit requirements for discharges in the Arctic.
