|Clio pyrimidata a thecosome pteropod. We are currently assembling a transcriptome for this species and investigating its responses to ocean acidification. (photo by A. Maas)
|Enlarge ImageGolfball coral Favia fragum we are studying individual variation in responses of juvenile corals to ocean acidification. The coral is in a jar so we can collect larvae each morning. (A.M.T.)
|Enlarge ImageGuest student Caitlin Church collects coral larvae and places them in a small chamber to allow them to settle on terracotta tiles. (A.M.T.)
Climate change, broadly speaking, is a cross-cutting motivation for much of our work. Some current and recent projects including studying thermal stress on reefs, effects of ocean acidification on corals and pteropods, and effects of hypoxia and chemical pollutants on fish physiology. In each case, we are interested in the capacity of animals to adapt and respond to changes in their environment, and the consequences of such responses to the organism.
Two examples of current projects related to climate change are described below.
Effects of Ocean Acidification (OA) on Corals: Is individual variability important?
This is part of an NSF-sponsored project (PI’s Anne Cohen, Dan McCorkle, Samantha dePutron, Ann Tarrant). Some objectives of the proposal are to quantify the effects of OA on the growth of juvenile corals, and to determine the degree to which nutrition (heterotrophic feeding or photosynthesis by the symbionts) can offset the effects of acidification.
The Tarrant lab is investigating the effects of individual variation on the growth of coral larvae and their sensitivity to OA. The corals being studied are Porites astreoides and Favia fragum. In both species, the maternal colony releases brooded larvae into the water column. A maternal colony may release larvae that were fertilized by multiple paternal colonies, or even self-fertilized. Larvae from different maternal colonies may have different physiological characteristics, due to a combination of genetic and environmental effects.
Impacts of ocean acidification on pteropod physiology
Thecosome pteropods are a group of pelagic gastropods that produce thin shells of aragonite, a form of calcium carbonate. It is still unclear how ocean acidification will affect pteropod physiology, including their ability to form shells and the energy required for shell formation. Using next-generation sequencing techniques, we are working to assemble a pteropod transcriptome and determine how gene expression is affected by short-term exposure to acidified water.
This project is currently funded by the WHOI Access to the Sea Program. Postdoctoral scholar Amy Maas is leading these efforts in collaboration with Gareth Lawson's laboratory at WHOI.