The Coastal Waters Consortium is made up of a diverse group of scientists all committed to better understanding how the Deepwater Horizon oil spill has affected our wetland habitats. We have scientists looking at plants, sediments, birds, fish and even worms. For most people worms, are one of two things: disgusting or boring. Dr. Kersey Sturdivant views worms in a completely different light. He is able to understand and appreciate the critical role these organisms have in the benthic ecosystem. It is well known the positive influence that terrestrial worms have on gardens by eating dirt and digging burrows, but many people do not realize that terrestrial worms have aquatic counterparts who do similar things. The consumption of sediment combined with the burrowing activities reworks the sediment in a process called bioturbation. This process promotes, aeration (an increase in oxygen levels), and mixing up the sediment and the nutrients to create a healthy bottom.
Since these organisms are so important to benthic ecology, Dr. Sturdivant was curious to discover what affects the oil spill might have on those organisms. Since September 2012, Dr. Sturdivant has been using the aptly nicknamed “Wormcam” to monitor the polychaetes (worms) and other macrobenthos (animals within the sediment) movements in the sediments. The study compares locations within Terrebonne Bay that were defined as heavily oiled versus sites that were considered not as heavily oiled. The Wormcam is a precise combination of a mirror, strobe, and camera that allow us to be able to see a small profile of life underneath the sediment. Wormcam is set to take one still picture every half hour. With combined water quality data we get a very good view of what is occurring below the surface and relate it to the water quality. In order to minimize the amount of time spent servicing the equipment, it is connected to a buoy with solar panels. All of these data are saved to a memory card (as back-up), and are also sent in real time via satellite.
The study is still ongoing and data is still being taken from the field. Dr. Sturdivant has been noticing some interesting observations. All of his study sites are shallow water systems and he sees that the area is heavily wind driven. So during high wind events there is an influx of detritus from the marsh into the study areas. The data have also shown that with this influx of detritus it actually changes some of the behaviors of the worms. In the heavily oiled sites there is less burrowing and bioturbation activity during these events as compared to the non-oiled sites. This observation is one more piece of the puzzle in the long-term big picture that our CWC scientists are determined to understand. It could be that during these high wind events oil pockets that have been sequestered in the marsh re-enter the water column. It could be the toxins from these pockets are causing our worms to burrow less. Wormcam continues to collect data and we look forward to learning more about the data from Dr. Sturdivant