Over the past six years, marine ecologist Stuart Sandin and his team at Scripps Institution of Oceanography at UC San Diego have conducted research on islands all over the world as part of the 100 Island Challenge. The program’s goal is to establish a regional-scale perspective of coral reef health—investigating how reefs are structured, how they change over time, and how society can better manage them in the face of global change.

Sandin is a professor in the Marine Biology Research Division at Scripps and director of the Center for Marine Biodiversity and Conservation. He also serves as principal investigator of the 100 Island Challenge and leads a group of ecologists, biologists, and computer engineers to study the spatial patterning of coral reefs worldwide.

(Image credit: Stuart Sandin)

Although coral reefs cover less than 0.1 percent of the earth’s surface, they are estimated to support greater than 25 percent of marine biodiversity. For the hundreds of millions of people who live near coral reefs, this productive ecosystem provides important shoreline protection and critical food security. With recent news of coral reefs such as the Great Barrier Reef deteriorating due to worsening environmental conditions, it has become important for scientists to study their structures and learn what needs to be done to preserve them for future generations. We spoke to Sandin about his collaborative work to understand and protect this vital ecosystem.

ECO: How did you get started with the 100 Island Challenge?

Stuart Sandin (SS): Our team had been doing some work in the Central Pacific, largely in an archipelago where we were comparing what coral reefs look like on different islands. We discovered that there wasn’t one type of coral reef that existed across various islands but rather a spectrum, and the differences depended on various environmental factors. That’s what got us thinking, rather than try to understand all of coral reef ecology from one location, we should build an experiment around the variation that’s in nature. In order to gather enough data, we’d need to visit at least 100 islands and that’s what became the 100 Island Challenge.

ECO: What findings from the 100 Island Challenge surprised you the most?

SS: I’ve had two observations that have been unexpected. First, beautiful and healthy reefs appear on every island. This is surprising given that the common narrative for coral reefs is that they are all dying due to the negative effects of people like overfishing and climate change. While it is true that some reefs have been damaged significantly, we still find thriving reefs on almost every island, whether it’s due to people’s protection or the reef’s own resilience.

Perhaps most unexpected has been the observation that some reefs seem to be growing back stronger after marine heat waves. Anomalously hot water can kill coral reefs by killing the corals themselves, which is what we have seen in the Great Barrier Reef over the past 10 years. However, in some locations we see areas that experienced marine heat waves, but the corals survived. Interestingly, these areas appear to be in places that have had other hot-water events in recent years. The unexpected observation may be linked to adaptation; the coral community, when stressed once by hot water, recovers in an adapted way to be able to weather the next hot-water event with more rigor. We are continuing to study this encouraging observation with subsequent studies.

ECO: What first sparked your interest in science?

SS: I have always been curious about how the world works and how patterns in nature are made. I think science is my way of learning and exploring how the world works. The more that I learned, the more that I realized that many of these wonders of the world were being affected by people who didn’t care about the tomorrow of the natural world. I then turned to thinking about the human relationship with nature, and how we can modify it to live with mutual respect for people and for nature. Science again was my inspiration. I felt that through better understanding of the diversity of the natural world, and communication of this understanding, we had an opportunity to improve this relationship. And now I serve as director of the Center for Marine Biodiversity and Conservation at Scripps, another place where we work to get science into the hands of people across walks of life, people similarly interested in improving the relationship between people and nature in the sea.

ECO: What is your favorite part of the job?

SS: I enjoy working with colleagues worldwide and sharing in the process of learning. We work with colleagues in 17 countries who cover a vast spectrum of perspectives and backgrounds. The observations and views of coral reefs vary with geography, culture, and scientific background. The process of learning together with such a diverse set of colleagues is a real treat, and one that we covet!

This feature appeared in Environment, Coastal & Offshore (ECO) Magazine's 2021 Autumn edition, to read more access the magazine here.