Formation of petroleum-derived dissolved organic matter following chemical herder application and in-situ burning at high latitudes: molecular composition correlated with seawater microbial community diversity

Oil and gas drilling have been occurring in Alaska since the 1950s, and additional lease sales are planned for Cook Inlet and the Beaufort Sea. As regions in the Arctic become ice-free, offshore drilling in that area is expected to increase. As petroleum development increases so does the risk of another major oil spill. Oil spills can have a devastating effect on the marine environment and chemical herders and in-situ burning (ISB) are supposed to mitigate that effect. Despite some of the benefits this technique appears to have in oil spill mitigation, opinions on the utilization of these strategies are polarized, and the issue requires careful consideration and study. In this experiment, we investigated the effects of 1) addition of chemical herder Siltech OP-40, 2) combustion of crude oil, and 3) combustion of herded crude oil, on a) the chemical composition of petroleum-derived dissolved organic matter (DOMHC) and b) seawater microbial community diversity over 28 days at 4 degrees C in an aquarium-scale mesocosm experiment with seawater from Prince William Sound, Alaska.