Award: OCE-1043249

Our research was aimed at examining the response of the zooplankton community to the Deepwater Horizon oil spill. During mid-August to mid-September 2010, we participated in a collaborative research cruise aboard the R/V Oceanus in the northern Gulf of Mexico. During the cruise, we deployed a laser optical plankton counter (LOPC) to determine zooplankton vertical distribution and abundance in the water column and collected mesozooplankton for extraction of oil derived contaminant compounds that may have been incorporated through exposure. We sampled the area immediately surrounding the Deepwater Horizon spill location and a location to the south of the well. Our first major outcome of the research was that we found no difference between zooplankton biomass or abundance near the wellhead or offshore. Zooplankton estimates using the LOPC were comparable to those found by other researchers in the northern Gulf of Mexico. These results must be viewed with some caution as they are LOPC estimates and must be compared to net estimates of zooplankton. Our second major outcome is that we discovered oil derived compounds (polycyclic aromatic hydrocarbons (PAH)) were present in zooplankton collected from all locations we samples. We used a gas chromatograph to characterize a suite of PAHs from both zooplankton and oil collected from the Gulf of Mexico and the Deepwater Horizon riser pipe. The PAH signatures of both oil samples matched zooplankton PAH signals suggesting that the PAH compounds found within zooplankton were derived from the Deepwater Horizon spill. It was not clear from our research whether or not the PAHs found in zooplankton were readily transferred up the food web; however, our results do confirm that zooplankton were taking up these compounds for a significant time period during and after the spill. Last Modified: 09/08/2011 Submitted by: David G Kimmel