Discovering New Ways to Understand the World
Assistant Professor Aleja Ortiz has received a prestigious grant to study atolls
Alejandra C. Ortiz has always been captivated by atolls, the low-lying coral reefs and islands that play a critical role in coastal ecosystems and are particularly vulnerable to the effects of human activities and a changing climate.
Ortiz, an assistant professor of environmental studies and a coastal geomorphologist, uses a mixture of fieldwork and remote modeling, including the use of artificial intelligence, to understand the primary processes driving coastal evolution and to learn more about what places like atolls will look like centuries into the future.
Doing the work isn’t easy. A single atoll can be home to hundreds of islands, and they are often found in remote parts of the world that are difficult and expensive to get to in person. Those realities pose challenges to scientists who want to learn more about them, which is why she has turned so much to satellite and modeling work.
“I see it as a way to bridge some of those limitations,” she said.
Ortiz has recently received a major vote of confidence in the unique way she approaches atoll research. In December, she learned she was selected to receive a major grant from the National Science Foundation that will allow her to identify atolls most at risk of land loss and create a detailed, reproducible approach to studying atoll island change and resilience.
“I’m really excited because the atoll work is something that, until now, has been mostly what I would think of as a passion project,” Ortiz said. “One of the big pieces for me is the validation from my own scientific community that this is valuable work, and that I’m the person to push forward on it. That’s really something that I’m proud of.”
A prestigious grant
According to the NSF, the Faculty Early Career Development Program grant is one of the most prestigious awards offered by the foundation. It’s designed to support early-career faculty who have the potential to serve as academic role models in research and education and to help them build a firm foundation for a “lifetime of leadership” in integrating education and research.
“It really does change careers for people,” Ortiz said.
Half of the grant funding is dedicated to education and the other half to research, and it will make it possible for her students to participate in valuable fieldwork.
She’s currently mapping out her strategy for the research. One of her goals is to continue developing a way to use satellite imagery and remote sensing data to accurately measure the size and shape of atolls globally. Previously, scientists did this by using existing maps, aerial photographs, or satellite images and then tracing each island by hand, an approach that is precise but slow, she said.
Her method is much less labor-intensive. With the help of students, at Colby and her previous institution, North Carolina State University, she has so far measured around a quarter of the world’s roughly 450 atolls.
“This grant is really going to expand some initial work that we’ve done both in spatial coverage and then track how they’re changing through time with satellite data,” Ortiz said. “One of the things that I’ve been working on more recently was how we can leverage different AI tools to help us expand that analysis. And then, can we look at how the atolls have changed through time? The idea is that it gives us a better sense of where we’ve seen significant areas of increased land growth and increased erosion, or land loss.”
Understanding atolls
Atolls are created through a complex geologic process that starts with the eruption of underwater volcanoes, called seamounts. When a seamount grows tall enough and breaks the surface of the water, its top becomes an oceanic island. In warm water, tiny sea animals called corals start to build a reef around the island with billions of their limestone exoskeleton. Then, over millions of years, the volcanic island erodes and sinks through a process called subsidence, leaving a coral reef surrounding a lagoon where the island used to be.
Although much is known, there are still unanswered questions about atolls, Ortiz said, including what drives the evolution of the landscapes. Is it primarily waves and storms, or is it primarily the creation of sediments such as sand? The grant funding will help her explore these questions.
“The idea is that it will give us a very first order approximation of whether offshore waves and storms are primarily what drives the size and shape of these islands and their evolution, or whether it’s actually something else,” she said. “And something else is probably related to sediment production, and how healthy the corals are.”
Another part of the project will incorporate morphodynamic models, physics-based computer simulations that help scientists understand how landscapes made of materials like sand change over time through water movement and other factors. Those models can be run forward in time, Ortiz said, meaning that she can input data about waves and other factors and see what the model predicts will happen to the landscape a hundred years or more into the future.
“That gives us a better sense of what the resilience of these systems might be in the future,” she said.
Comparing predictions with reality
Another of Ortiz’s goals is to start a long-term field research site on Glover’s Reef, an atoll almost 28 miles off the coast of Belize. She plans to collect field data there regularly, including through teaching Jan Plan courses in collaboration with colleagues in the Environmental Studies Department. They will be able to compare what the morphodynamic model thinks will happen with what actually does happen.
“That’s how you validate, and make sure that the model is working the way you think it is,” she said.
The Colby group will look intently to see how sea level rise and changing storm intensity, both of which are affected by climate change, could impact Glover’s Reef. Ortiz will use data collected from the last 30 years and run morphodynamic models to imagine possible future scenarios.
“When you think about tropical islands, it’s very easy to immediately assume doom and gloom. But if you look at the data, that’s not necessarily what we’ve been seeing,” she said. “I think it depends on the focus. If the focus is, will there still be atolls 100 years from now, there probably will be. Will they still be inhabited by the existing nations? Not easily, not without a significant change in ways of living.”
She hopes that the students who come to the atoll will be interested in and excited about the possibilities of what they can do and learn.
“I think that the best part of being a scientist is finding new ways to think about the world,” Ortiz said.
