About This Project

Shells defend marine snails from crab predators, but it is difficult to produce shells with ocean acidification because there are fewer building blocks available in the water. I will test snails' abilities to defend themselves in acidified water and find out what types of snails are most resilient. We know very little about how climate change will alter predator-prey relationships, so this will help us predict changes in marine communities and manage and conserve snail populations.

Ask the Scientists

What is the context of this research?

Inducible defenses, or the ability of species to produce defensive structures or compounds when they are threatened, is common in terrestrial and marine environments. For mollusks and other shelled marine organisms, this typically means producing a thicker shell when they sense the presence (chemical cues) of a predator. However, ocean acidification as a result of higher carbon dioxide levels in the atmosphere and the ocean can make it more difficult for some calcifying species to produce shells. The resulting thinner or weaker shells make some species like oysters or mussels more vulnerable to predators. Despite how important inducible defenses are in marine systems, we don't know how they respond to ocean acidification or changing ocean temperatures.

What is the significance of this project?

This would be the first project to test whether or not ocean acidification affects inducible defenses of multiple marine species. The vast majority of climate change research has focused on responses of individual species, but we know that species interactions drive ecological processes in most ecosystems on land and in the sea. Multiple reviews of scientific research on climate change have concluded that understanding the effect of changing ocean conditions on marine communities (instead of single species) is a major gap and important area for future research. If we don't understand how one change in one species ripples through the benthic community, we are unable to make predictions about impacts of climate change or effectively manage fisheries and conservation areas.

What are the goals of the project?

To test how snail defensive abilities respond to acidification, I will weigh snails and then put them in tanks, half of which contain green crabs. I will feed snails with purchased mussels and maintain pH levels of 8.0 and 7.6 using the CO2 control system. Ocean pH is around 8.0, and pH 7.6 represents future acidified conditions, with fewer shell building blocks available in the water.

I will weigh snails again at the end of the experiment to see how thick the new shell is. I will cut off the new shell area and send it to a lab for X-ray diffractometry, which will tell me if acidification changed the shell chemical makeup. I will do this in February-May 2017, publish the results in a scientific journal and present them at the Western Society of Naturalists conference.