Dr. Drew Harvell (Professor of Ecology and Evolutionary Biology at Cornell University)

Dr. Drew Harvell

What are your main concerns pertaining to marine life and the oil spill?
Dr. Harvell: I think it would be important to track the biodiversity impacts of this issue because they are huge. The water-column species, jellyfish, invertebrate larvae, fish larvae (spawning tuna) are directly in contact with the spill. I think that is really important. I would like to see a biodiversity calendar to document the losses.
Another thing we worked on for many years in the Florida Keys was studying the coral populations. We were interested in doing a rapid response after the oil spill because even if the oil doesn’t hit, we expect there should be a lot of stress. I heard from some of the folks in the Florida sanctuaries that oil is expected to hit the Keys. And if they get hit, there are expected to be pretty big impacts.

What marine invertebrates and plants are at greatest risk?
Dr. Harvell: It’s easy to say the coral is at risk. But there are also a lot of invertebrate larvae that are very fragile and summer is the spawning season [when] so many of them will be exposed. And one thing I would say, for a crab and coral – a crab has an exoskeleton, coral has nothing. Every bit of the surface area is exposed for these corals. And of course that’s really disastrous because these corals make coral reef ecosystems that are home to many other plants and animals.

Could you provide a public-understandable description of how corals feed?
Dr. Harvell: Corals are basically solar powered. Most of their nutrition comes from the symbiotic relationship with the algae that live in their tissue. They need clean water for photosynthesis. There are some species that are carnivorous and capture zooplankton at night with their barbed tentacles. So not all are filter feeders, but it’s the sunlight that’s the most important part of their diet. The algae live in the tissues and create the food. But they are kind of like the “Achilles heal” of the coral because they are easily disrupted by temperature stress, and this summer has been hot. If there is an oil hit combined with the hot summer, the results will be disastrous. The symbiosis between the algae and coral can be disrupted very easily.
Corals are really complicated. It’s not just the symbiotic algae but also the bacteria that live on the surface of the coral, and they are important to the health of the coral too. If there is oil and dispersants hitting them, that could really disrupt the coral. And I would suspect an increase in coral disease.

What effects would oil in the water have on how corals feed?
Dr. Harvell: What I think will happen is that it will disrupt the symbiosis. It would affect the way they feed, and if they bleach, then the coral is going to die. In terms of the carnivorous feeding, I don’t know how the oil would affect that. But what coral tends to do when they are stressed, they tend to retract their tentacles and not feed. Even if they didn’t lose the symbionts, the oil could cause a loss in sunlight and make it harder to produce their food.

How might the spill affect existing problems like pollution runoff, coral bleaching, red algal blooms, etc?
Dr. Harvell: I don’t know. I don’t know how those will interact with the oil spill. All I can hope is that this spill was so terrible that it will make it so this won’t happen again. Hopefully we'll have policy changes in that way. This is a continuing conflict; we need to harvest energy while balancing our sustainability.

For more information on Dr. Drew Harvell, visit http://www.eeb.cornell.edu/harvell/harvell.html