Stout razor clams may be on the cutting edge of oil spill cleanup, according to 小蝌蚪APP researchers.
After simulating an oil spill, faculty and student researchers found coastal sediments that held razor clams retained 25 percent less oil than areas where the mollusks weren小蝌蚪APP檛 present.
That could mean clams are absorbing oily residue, or they might be burying it. Either way, they小蝌蚪APP檙e acting as frontline custodians combatting environmental crises, said Dr. Paul Klerks, a UL Lafayette and one of the project小蝌蚪APP檚 investigators.
小蝌蚪APP淥ur research shows that evaluations of oil spill impacts need to consider how animals living in coastal areas may influence what happens to the oil. Studies like these are important because they help determine where spilled oil will be found and how fast it will disappear,小蝌蚪APP Klerks said.
Razor clams are bioturbators, which means their burrowing reworks and moves sediment in the beaches and coastal estuaries where they live. They are ubiquitous in the western Atlantic Ocean from Cape Cod to Argentina, and throughout the Gulf of Mexico.
Feeding and digging by these 小蝌蚪APP渆cosystem engineers小蝌蚪APP can redistribute contaminants over a wide geographic area, potentially exposing other sea creatures to pollutants as well.
UL Lafayette researchers used a series of 30-gallon aquaria to replicate the aftermath of the Deepwater Horizon oil spill in the Gulf. The team wanted to determine how the light-shelled, semi-cylindrical clams affected what happened to the oil.
Investigators used oil similar to that which inundated Gulf shorelines following the rig小蝌蚪APP檚 2010 explosion, weathering it slightly to mimic the chemical changes that happen when petrochemicals mix with seawater. They then exposed the oil to sand that contained razor clams and other sediments that did not.
Researchers found the clams小蝌蚪APP presence reduced contaminants on the sediments小蝌蚪APP surface by 25 percent; however, the team noted the level of toxins below the surface had not increased, Klerks said. 小蝌蚪APP淲e checked oil levels below the surface to assess whether the clams were burying the oil. If they were, then there should have been less oil at the surface and more oil in deeper sediment.
小蝌蚪APP淲e found some evidence for burrowing,小蝌蚪APP but not enough to conclude definitively that the oil小蝌蚪APP檚 fate rested below the sediment surface.
Where did it go? Researchers then considered microbial breakdown. That process would involve razor clams and bacteria working in tandem to eliminate the oil, Klerks explained
小蝌蚪APP淪ome bacteria basically eat the oil and break it down. It小蝌蚪APP檚 food for them.小蝌蚪APP
The clams小蝌蚪APP burrowing could affect what kind of bacteria and how many occur in sediment and water. In turn, that could increase how quickly the oil breaks down.
Researchers tested this theory, but did not find a difference between the tanks with clams and those without.
Questions remain. While it is clear the clams小蝌蚪APP presence affected the oil, Klerks said more study is needed to determine how and why. Another avenue 小蝌蚪APP researchers are examining: how Gulf ghost shrimp interact with pollutants.
Like razor clams, ghost shrimp burrow into sediments, but tend to be more reclusive. They 小蝌蚪APP渁re very abundant and very active. They make burrows that may be as much as 10 feet deep, so they are likely to have even more of an impact than razor clams,小蝌蚪APP Klerks said.
He explained that the tunnels小蝌蚪APP depths mean ghost shrimp move more sediment than razor clams do. That results in more oxygen below the surface and more bacteria that potentially could consume 小蝌蚪APP and therefore combat 小蝌蚪APP toxins.
The new findings on how both organisms help the environment cope with contaminants 小蝌蚪APP渦nderscore the importance of healthy coastal systems,小蝌蚪APP Klerks added.
小蝌蚪APP淪o much depends on a vibrant coastline, from the seafood and tourism industries to the fish, shrimp and oysters we buy in the stores. Studies such as these help people decide when it is safe to go back to beaches or eat seafood following an environmental crisis.小蝌蚪APP
The Archives of Environmental Contamination and Toxicology published the team小蝌蚪APP檚 razor clam study in its August 2018 issue.
In addition to Klerks, its authors are Alex Kascak and Nihar Deb Adhikary, doctoral students in the Department of Biology; Dr. Alfy Morales Cazan, a postdoctoral researcher in the and biology departments; Dr. Andrei Chistoserdov, associate professor of biology; and Dr. Febee Louka, associate professor of chemistry.
Two additional authors, Amalia F. Shaik and Sommer Osman, were undergraduate researchers on the study. Both have since graduated from UL Lafayette; Shaik earned a bachelor小蝌蚪APP檚 degree in microbiology and Osman completed a bachelor小蝌蚪APP檚 degree in chemistry.
A Gulf of Mexico Research Initiative grant partially funded the study. GoMRI is a 10-year independent research program established to study the environmental effects of oil spills.
Photo caption: Razor clams are ubiquitous in the western Atlantic Ocean from Cape Cod to Argentina, and throughout the Gulf of Mexico. (Photo courtesy of Dr. Darryl Felder / 小蝌蚪APP)