Monday, June 30, 2014

Summer Sampling Part II - The Rain in Galveston Falls Mainly on the Reddy Lab

One way that chemists use to determine how oil changes over time, or "weathers," is to use controlled laboratory experiments where oils are exposed to different environmental conditions (heat, sunlight, water-washing, bacteria). While these laboratory experiments have provided insights into some of these weathering processes, it is really difficult to accurately reproduce the real-world combination of environmental factors that lead to chemical weathering of oil. Our goal with these long-term field collections is to collect oil samples at many time points as they undergo real-world weathering. This trip marks our third time collecting samples from the Kirby oil spill since the spill occurred in late March 2014, and will allow us to compare the early weathering of oil from the Kirby spill to the weathering processes that we observed with oil from the Deepwater Horizon spill. 

Torrential storms followed us from Louisiana to Texas where our first night of sampling was a soggy one. But, being the intrepid scientists that we are, we braved these storms and the accompanying tornados and went about our work. Thankfully, the tornado activity was centered to the west of our sampling locations. 

A wall cloud rolls through the north end of Galveston Island, bringing heavy rains as part of a system that spawned tornadoes farther inland. Photo credit: Bob Nelson.
Despite the fact that much of the 168,000 gallons of oil spilled from the Kirby washed out of the Houston ship channel to oil beaches as far as 200 miles to the south, we were still able to find samples resembling this sticky, tar-like oil along the north shore of Galveston Island. The cleanup effort for this spill was largely effective, but it is practically impossible to remove all of the oil from a spill. This is especially the case with intermediate and heavy fuel oils like the Kirby oil. Turning over rocks along the beach yielded fresh looking oil and many areas of the rock jetty along the shore were spotted with oil covered debris. 

Chemistry graduate student (University of Campinas, Brazil), Hector Koolen, scraping oil from marsh grass along the north shore of Galveston Island. Photo credit: Bob Swarthout.
Oil covered rocks and debris found along the north shore of Galveston Island. This oil is likely weathered remnants of the Kirby oil spill. Photo credit: Bob Swarthout.

On our first trip to Texas, Bob Nelson and I were able to collect Kirby samples along the gulf coast in Galveston and 200 miles south on Mustang Island near Corpus Christi. But locating samples during this trip was again hampered by the massive amounts of seaweed on the beaches and the associated cleanup effort. The seaweed has been coming ashore for about two months in larger than usual quantities. Many municipalities, parks, and hotels use bulldozers and front loaders to clear seaweed from their beaches to encourage tourism. This cleanup effort also removes sand and can remove any oil samples that may be present.While this is a good thing for beachgoers,it resulted in our being unable to find any samples resembling Kirby oil along the eastern beaches of Galveston Island. 

A front loader clears seaweed from the beach in front of a hotel on Galveston Island. Photo credit: Bob Swarthout.

In spite of the seaweed, this trip was still a big success for our lab. We continue to grow our collection of samples from Deepwater Horizon extending our time series to over four years. And, we now have three separate time points for the Kirby spill which will allow us to examine weathering trends for this intermediate fuel oil. Now it's back to the lab at WHOI to get on with the comprehensive chemical analyses that will tell us just how much these two oils have changed since our last visit to the Gulf.

Post submitted by: 

Bob Swarthout, The Reddy Lab
Woods Hole Oceanographic Institution

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