Living things find amazing ways to stay alive between 200 and 5,000 meters below the surface, where sunlight stops shining. Bioluminescent lures are dangled by anglerfish in almost total darkness. Species that don’t have common names float through the water at pressures that would squash a car. Science had only just begun to sketch out this world, which most people will never get to see. Nova Southeastern University’s research program is centered on the open ocean and its deepest parts. They are now trying to figure out not only what lives down there, but also how those animals are adjusting as the ocean above them changes slowly and clearly.
The Halmos College of Natural Sciences and Oceanography at NSU is where the program is based, and it covers a lot of ground. Tracey Sutton, one of the best deep-sea ecologists at NSU, has spent years tracking life in the “deep-pelagic zone,” which is the large, dim area of the ocean floor between the sunlit surface and the deepest parts of the ocean floor. Through his work, he has found species that no one had officially named before. In 2015, his team found and named a new species of anglerfish in the northern Gulf of Mexico. The fish were caught between 1,000 and 1,500 meters deep. Three females, each one just a bit bigger than your thumb. Each species that hasn’t been named is like a missing piece of information in our understanding of how these ecosystems work and how they might react when things change.
How they answer that question is more important now than it was even ten years ago. The oceans off the coast of Florida have been getting warmer, which has been scary for ecosystems in shallow water like coral reefs. As water temperatures rise above normal for the season, bleaching events have been seen along the coast of South Florida. Some types of coral, like boulder and brain corals, can handle more heat than others, according to research done at NSU. This information is now helping restoration teams choose which corals to plant and where to put them. What goes on deeper, though, is harder to see and understand in some ways.
Marine scientists think that communities deep in the ocean aren’t as affected by changes in the temperature of the surface because the cold is more stable there and the changes happen more slowly. It’s possible that’s partly true. But heatwaves under the ocean, which NSU researchers have studied with researchers from other institutions, can raise temperatures in some ocean layers by up to five degrees Celsius above normal during certain times of the year. A systematic approach is being used by the program to try to figure out how far that thermal disruption goes and what it changes when it gets there.
The mix of scale and specificity in NSU’s approach is what makes it worth paying attention to. By keeping an eye on hundreds of different animals across huge areas of ocean, shark tracking alone collects movement data that shows when and where species are moving their ranges. A shark that changes the way it migrates is more than just a piece of information. It means that something has changed in the water column. The same reasoning works further down. When deep-sea species show up in places they didn’t expect to, or when communities that were stable before start changing, those are the first signs that the temperature change isn’t staying at the surface.
Scientists still don’t know a lot of things. Not to be polite, but that’s the truth of the matter. More than once, Sutton has said that the ocean’s interior is not yet fully mapped out. People are still finding new species. It’s still not clear how ecosystems work together. It is very hard to keep track of how a system is responding to climate change when that system isn’t fully mapped out yet, and the researchers at NSU don’t try to hide how hard it is.
It’s clear that the deep ocean off the coast of Florida is not a fixed record. It’s a living system that’s linked to everything above it, from reefs dying to currents changing and surface waters getting warmer. The scientists who are cataloging it aren’t working in a vacuum; they’re also watching the bigger crisis above them. From the outside, it’s hard not to think that the work in the deep sea, on reef restoration, and on sea level research are all leading to the same unsettling conclusion: the ocean is changing faster than we can learn to keep up with it.
