Discovery Magazine

Photo Credit: Ken Dunton

Chukchi Seas Offshore Monitoring in Drilling Area (COMIDA)

The Chukchi Seas Offshore Monitoring in Drilling Area (COMIDA) Project was designed to meet the following objectives: (1) Establish a baseline for the benthic environment including biomass, species composition and oil industry anthropogenic chemicals to detect changes as the result of future oil and gas activities, (2) Initiate past and future time trend analyses for the benthic environment and anthropogenic chemicals, (3) Distinguish among changes in arctic biogeochemistry due to development, climate, and food web structure, (4) Identify natural and anthropogenic sources of contaminants to the study area, (5) Initiate and develop a conceptual food web related to bioaccumulation and risk of trophic transfer of oil industry anthropogenic chemicals.

The Chemical Oceanography group from Florida Institute of Technology (FIT) will lead the effort on arctic biogeochemistry and anthropogenic chemicals with a 2-year sampling strategy for collecting surface sediments to determine standard sediment hydrocarbon parameters such as polycyclic aromatic hydrocarbon (PAH), relevant metals, including the Environmental Protection Agency (EPA) priority metals [total iron (Fe), manganese (Mn), aluminum (Al), barium (Ba), chromium (Cr), vanadium (V), lead (Pb), copper (Cu), cadmium (Cd), nickel (Ni), arsenic (As), silver (Ag), mercury (Hg), selenium (Se), beryllium (Be), thallium (Tl), tin (Sn), antimony (Sb), and zinc (Zn)]; supporting/normalizing parameters such as grain size, organic carbon or organic matter, etc.; and sourcing parameters such as diagnostic hydrocarbon ratios. The biological sampling is combined with the sediment sampling and other sampling/assays/analyses to complete a sediment triad approach to evaluating effects of ambient anthropogenic chemical levels.

Pre-drilling activity baseline sampling was conducted in 2009, emphasizing the area leased by industry in the proposed Chukchi Sea oil and gas lease sale held in February, 2008. Additional adaptive sampling occurred in 2010, predicated on the findings and success in 2009 and locations of likely oil industry post-sale activities. Dated sediment cores are used to capture interannual variability of anthropogenic chemicals and to track diagenetic processes that affect the arctic biogeochemistry of metals such as As, Cd and Mn. Sampling design will be adaptive to incorporate locations of concentrated bird and marine mammal feeding and their prey within the COMIDA area. To identify sources of anthropogenic chemicals to the study area, limited sampling will be conducted of sources such as water column, air, drilling mud, river input, seeps, or shoreline erosion.

A conceptual food web model related to bioaccumulation and trophic transfer of potential oil industry contaminants is part of initial study planning based on literature review and data-mining. Water and biota sampling are conducted to better understand pelagic/benthic coupling and other trophic transfer within the context of arctic biogeochemistry. The food-web model will be risk-based, conceptually considering mechanism, magnitude, and likelihood of contaminant transfer. The model will continue to be developed and updated throughout COMIDA, incorporating COMIDA results and other information, and will also be used as a tool to refine sampling strategy during COMIDA and recommend the post-COMIDA monitoring strategy.