Mesophotic Deepwater Coral Reefs

Coral and live bottom (hard bottom inhabited by dense cover of corals, algae, sponges and other attached species) are not adapted to living with oil and gas, unlike cold seep communities. As summarized in a NOAA fact sheet (PDF), “impacts of oil spills to coral reefs are difficult to predict because each spill presents a unique set of physical, chemical, and biological conditions.” The most likely way deep reefs will be exposed is to weathered oils that sink and travel in mid-water plumes and mix with sediments. Dispersants act to break up light oils into small particles, which may actually increase exposure on deeper reefs. The NOAA Fact sheet includes related research links.

EXPEDITION OBJECTIVE– ASSESSMENT OF OIL IMPACTS OF DEEP CORAL AND MESOPHOTIC REEFS

[John Reed, (leader), M. Dennis Hanisak, Ph.D.; Joshua Voss, Ph.D., Shirley Pomponi, Ph.D., Amy Wright, Ph.D., Tammy Frank, Ph.D.]

Coral reef and benthic hard-bottom ecosystems support vast amounts of the ocean’s biodiversity and exhibit exceptional variation in relative forms, functions, origins, and locations. Given the magnitude, location, and depth of the Deepwater Horizon oil spill, a major concern for offshore impacts is the impact on coral reefs, particularly the deep coral and mesophotic reefs found throughout the Gulf of Mexico and along the southeastern US continental shelf. Impacts on these reefs and hard-bottom communities may severely reduce ecological functions, ecosystem services, and quantifiable economic value. These impacts may vary considerably in these understudied, poorly documented coral habitats. Using the in situ capabilities of a the research submersible and ROV, pre- and post-impact assessments and documentation of critical deep and mesophotic coral reefs will establish baseline data sets needed for planning future monitoring and restoration efforts.

EXPEDITION OBJECTIVE: STRESS RESPONSES OF CORALS AND OTHER MARINE INVERTEBRATES EXPOSED TO OIL AND CHEMICAL DISPERSANTS

(P.I. Sara Edge, Ph.D., Joshua Voss, Ph.D.)

Molecular biomarkers are valuable early diagnostic tools to measure detrimental changes in an organism’s physiological state due to chemical, physical or biological stress. Gene microarrays provide researchers with a tool that is capable of measuring responses that are sublethal and/or precede major physiological events or death. Microarrays have been used in a number of ecological studies including identification of toxicity stress in fish, crustaceans and coral. A cnidarian , stress-focused microarray, developed by Dr. S. Edge, HBOI, has been used to study how corals respond to natural and anthropogenic stressors in the lab and the field. Gene expression analysis has also been used to detect coral stress related to heavy metal contamination, exposure to pesticides, herbicides, polyaromatic hydrocarbons (PAHs) and organic compounds bound to sediments.