Oil Spill Puts Cold, Deepwater Corals At Risk

From Science Daily
Thousands of barrels of oil are leaking out of the Deepwater Horizon site each day. The oil ascends from depths of approximately 1502 m. (4928 ft.), but not all of it reaches the sea surface. The stratified seawater of the Gulf of Mexico captures or slows the ascent of the oil, and the addition of dispersants near the oil source produces tiny droplets that float for a considerable time in the water column and may never reach the surface.

According to Drs. Gregor Eberli, Mark Grasmueck, and Ph.D. candidate Thiago Correa of the Marine Geology & Geophysics division of the University of Miami (UM), the oil that remains in suspension in the water column and creates plumes poses a serious risk for the planktonic and benthic (sea floor) life throughout the region, including the deep-sea reefs they study.

“The deep water communities within the Gulf of Mexico and in the Straits of Florida are well hidden from us, but they include many species of cold-water corals that live in water at depths of 600 — 1500 m. (1969 -4921 ft.) in waters as cold as 3° Celsius (37.4°F),” said Eberli. “Unlike their more familiar shallow-water counterparts, these corals do not live in symbiosis with unicellular algae called zooxanthellae, but are animals that feed on organic matter floating through the water column. We know that most of the food consumed by the cold-water corals is produced in the surface waters and eventually sinks down to the corals.”

The large plumes being created by the oil spill, some of which are reported to be several miles long, sit in the water column situated between this source of food and these deep-water corals. As organic material sinks through the water column it passes through the oil plumes and is contaminated by micron-sized oil droplets.

“It is most likely that the delicate cold-water corals are not able to digest these oil-laden food particles and will perish in large numbers,” said Eberli. “We are especially concerned because the migrating oil plumes have the potential to destroy or greatly diminish these deep-sea coral communities as they are carried by the currents. These corals are important because they are the foundation of a diverse ecosystem that at last count includes over 1,300 marine species, according to Dr. Thomas Hourigan at NOAA.”

Dr. M (1729 Posts)

Craig McClain is the Assistant Director of Science for the National Evolutionary Synthesis Center, a National Science Foundation supported initiative. He has conducted deep-sea research for 20 years and published over 50 papers in the area. He has participated in and led dozens of oceanographic expeditions taken him to the Antarctic and the most remote regions of the Pacific and Atlantic. Craig’s research focuses on how energy drives the biology of marine invertebrates from individuals to ecosystems, specifically, seeking to uncover how organisms are adapted to different levels of carbon availability, i.e. food, and how this determines the kinds and number of species in different parts of the oceans. Craig’s research has been featured on National Public Radio, Discovery Channel, Fox News, National Geographic and ABC News. In addition to his scientific research, Craig also advocates the need for scientists to connect with the public and is the founder and chief editor of the acclaimed Deep-Sea News (http://deepseanews.com/), a popular ocean-themed blog that has won numerous awards. His writing has been featured in Cosmos, Science Illustrated, American Scientist, Wired, Mental Floss, and the Open Lab: The Best Science Writing on the Web. His forthcoming book, Science of the South (http://www.scienceofthesouth.com/), connects cultural icons of South such as pecan pie with the science behind them.