Saving the Reefs

Can humans help corals adapt to a changing environment?

Cheryl Logan works with students

Photo by: Joan Iguban Galiguis

Cheryl Logan works with students in her lab at the Chapman Science Academic Center.

School of Natural Sciences associate professor Cheryl Logan has been part of a number of research teams looking into the health of coral reefs. We talked with her about her role as one of 12 members of an international committee appointed by the National Academies of Sciences, Engineering, and Medicine to look at the future of the reefs and about the challenges faced by women as they advance in STEM fields.

What is the goal of this committee?

Logan: Our task is to look at possible human interventions back on the reefs.

Bleaching is the process by which the colorful symbiotic algae that live inside corals are expelled – bleaching corals are bright white. This is bad because the algae provide corals most of their food. Bleaching doesn’t necessarily kill the corals, but if it is sustained over a long period of time, it can lead to mortality.

Within the United States’ jurisdiction, the primary concern is coral health in the Caribbean. In addition to warming, there has also been disease within the Caribbean corals, so they are not doing well at all.

Right now, we are on track for the worst-case emissions scenario.
Cheryl Logan

It is the responsibility of the National Oceanic and Atmospheric Administration (NOAA) to manage these reefs. Traditional management tools like marine protected areas have not been working, so NOAA wants to look at other interventions, such as moving heat-tolerant corals from places where they are doing well into the Caribbean, to see if they could potentially take hold there. They are also looking at things like artificial evolution, bringing corals into the lab, exposing them to warmer temperatures and trying to increase their thermal tolerance. The idea is that these more tolerant corals could then be out-planted back on the reefs.

The goal of this committee is to review the best available science regarding the possible benefits and risks of human interventions and come up with a decision framework that managers could use to decide whether they want to try to implement some of these strategies.

Why is the health of coral reefs so important?

Logan: Coral reefs are among the most bio-diverse ecosystems on earth, similar to rain forests. They provide habitat for fish and fisheries that a lot of people depend on for food, especially in smaller island nations. There is also the protection the reefs provide, from storms and waves. And then, of course, there is tourism. Coral reefs are places corals, so they are not doing well at all. people want to go SCUBA diving and snorkeling, to see the diversity of corals, fish, turtles and sharks.

You have worked on research that indicates, to a certain extent, the reefs are resilient and can bounce back. Under what circumstances can that happen?

Logan: Most of my coral reef research has been in modeling the future of corals in response to climate change. We use the output from global climate models, which tell us how the temperatures are expected to change in the next 20-50 years. Then, considering the physiological thermal threshold of corals, we can predict how corals would respond based on rising sea surface temperatures.

Our results depend largely on the greenhouse gas emissions scenario that we project. Right now, we are on track for the worst-case emissions scenario. Under those conditions, even when we include the ability of corals to acclimate or adapt to some extent, corals won’t be able to survive through the year 2100. Under lower emissions scenarios, we do see the possibility that corals could persist if they are able to adapt to the rising temperatures.

Moving in a different direction, the issue of getting more women into the STEM fields is attracting more attention these days. What do you see as the issues there?

Logan: Within the field of biology, at the undergraduate level and even at the Ph.D. level, it is actually more than 50 percent female at this point, so we are graduating more biology Ph.D.s that are women than men. But then there is the pipeline issue. As you go from Ph.D. to a post-doc, and then to the assistant and associate and full professor level, there is a huge drop-off.

When women graduate from Ph.D. programs, it is typically the time of their life that they are interested in starting a family. There is a penalty to your research productivity, especially at universities where tenure decisions are driven by number of publications. The productivity hit you take by starting a family when you are just beginning an assistant professorship can make this a very stressful time.

At the same time, some of the top coral biologists in the world are female. I have hope that things are getting better for women in science, but we need institutional changes. We need more family-friendly policies to encourage women to stay in academia, and modifications to the tenure process that don’t penalize women for starting families. And some of these changes are happening now.

What’s next for you?

Logan: I was awarded a Fulbright Fellowship to go to the Galápagos Islands next year to study coral thermal tolerance. During natural El Niño events, water temperature can get quite high and lead to bleaching. During the 1982-83 El Niño event, it knocked out about 90 percent of the corals in the Galápagos. But since then, among the corals that did survive, they appear to be more tolerant than expected. So part of my proposed project is to examine corals’ thermal tolerance windows and then take samples for genetics to understand if some of those corals are better adapted to changing temperatures.

In fact, my husband and I, both applied for Fulbrights, and he was also awarded a fellowship. He is a senior research scientist at the Monterey Bay Aquarium and will be studying hammerhead shark nurseries. So we are going to take our whole family – we have a two-year-old and a four-year-old – and live in the Galápagos for five months next year.