Texas A&M U. Oceanography professor Thomas Bianchi traveled to Louisiana on a grant from the National Science Foundation to research the effects of the oil spill on decreasing marshlands.

“The marshes were in poor shape due to a variety of factors before the spill occurred,” Bianchi said. “Such factors include the levees built along the Mississippi River, which have starved the marshes of sediment over many decades, due to the absence of annual river flooding, and channelization of the marshes from oil companies, which has resulted in saltwater intrusion and enhanced erosion.”

Mud delivered from flooding would enable the marshes’ trapped sediments to grow and resist erosion. However, with the rising ocean level and high rates of regional marsh erosion and subsidence on the Louisiana coast, the odds are against the marshes.

“If the marshes cannot trap sediment and raise their elevation each year, they will get waterlogged, decompose and collapse. These systems continue to erode each year, and it is a race against time to save them over the next few decades,” Bianchi said.

The marshes soak up anything in the surrounding areas; consequently, plants in the southernmost regions have absorbed the oil. Because of the bacteria that consume oil, it has seeped into the microbial loop and is a part of the food chain, causing detrimental effects on plants, animals and bacteria.

“Historically, this area has experienced some of the most extensive marsh loss in the U.S., and amazingly, it is still the second-most productive fishing region in the country, right behind Alaska, so there is an awful lot at stake here,” Bianchi said.

The research team sampled two metric tons of water using reverse-osmosis electrodialysis to study the dissolved organic matter. The goal was to observe the makeup and the origin of the molecules collected near contaminated and uncontaminated marshes in Barataria Bay, Louisiana.

Cook said the analysis of these samples in regard to marsh health is comparable to taking blood pressure, heart rate and a reflex test at an annual visit to the doctor.

“The key point is that we are not looking for oil, but instead we are focusing on the much more water-soluble chemicals that are formed from oil when it is decomposed by bacteria and sunlight,” said Michael Perdue, a professor of earth and atmospheric sciences at the Georgia Institute of Technology who contributed to the research.

The ocean’s water level rises each year due to thermal expansion, making it that much harder for the marshes to survive. The sea level elevates an average of 0.4 centimeters each year, but in Louisiana it rises 0.8-0.9 centimeters per year. Considering this issue alone, Louisiana could be underwater in 6,000 years.

“This is a naked-eye macroscopic view of what is really going on out there. There is still quite a bit of oil in the dissolved organic matter,” Bianchi said. “The marshes are pretty tough plants. If erosion doesn’t get them and eventually the oil dilutes, they are going to come back. But none of them are healthy anyway. Some of them probably will come back, but it will depend on location.”