Hilary Palevsky '07
Scientists can freely download the data that Hilary Palevsky ’07 and others are gathering.

Hilary Palevsky ’07 is the seafaring type. She spent part of her Ph.D. years in the North Pacific aboard a Chinese container ship, collecting data on dissolved oxygen levels in the ocean. Earlier she taught marine science to K–12 students on two-masted schooners in Long Island Sound. She also spent a year as a Watson Fellow talking to fishermen, scientists and policymakers about Atlantic cod fishing.

Her current position, as a postdoctoral scholar at the Woods Hole Oceanographic Institution on Cape Cod, is also, of course, ocean-focused. But instead of going out to sea to collect samples, she lets the data come to her.

Two thousand miles away, off the southeast coast of Greenland, three giant buoys float in a triangle, 12 miles to a side, each anchored to the ocean floor 9,000 feet below. Covering them are sensors that measure everything from temperature to salinity to dissolved oxygen.

The data are transmitted wirelessly—no ocean expeditions required. “These are up-and-coming techniques in the field of chemical oceanography,” says Palevsky, “and in interpreting the ocean’s role in the climate.”

Her focus is the data on dissolved oxygen—the amount of oxygen present in the water. She uses those measurements to calculate how much carbon from the atmosphere gets all the way down to the deepest parts of the ocean.

“Anything that sinks out of the surface can be sequestered from contact with the atmosphere on timescales from weeks to 1,000 years,” she says. Figuring out what proportion of carbon in the ocean may stay there for a millennium has important ramifications for climate change modeling.

Hilary Palevsky '07
Hilary Palevsky’s (major: geology) data-gathering is part of a 25-year undertaking, the Ocean Observatories Initiative.

Why use oxygen to study carbon? The two are intimately connected through photosynthesis and respiration. Algae produce oxygen and consume dissolved carbon dioxide; the high oxygen levels in the upper ocean (where sunlight can reach) are mostly from this photosynthesis. As algae get eaten, the organisms that eat them convert their carbon back into carbon dioxide via respiration, which simultaneously reduces the amount of dissolved oxygen.

There are huge advantages to getting such data remotely. Rather than taking individual snapshots of the ocean by going out and collecting bottles of water, the sensors gather data continuously, giving a much broader picture. The fact that the sensors gather data year-round is also important.

Palevsky’s work is part of a 25-year undertaking, the Ocean Observatories Initiative, that started gathering data in 2014. It involves not only the monitoring stations that provide Palevsky her data but also similar stations near Argentina, Chile, British Columbia, Oregon and Massachusetts. The data from the stations are freely available for scientists to download.

As this network of sensors continues to monitor the world’s oceans, the data that they provide—and that Palevsky and others are analyzing—will likely be incorporated into global climate models, like those created by the Intergovernmental Panel on Climate Change.

The more accurate those models, the better we can plan for the changes that are already inevitable—and the better we can evaluate methods for avoiding the most catastrophic outcomes of climate change. 

Geoffrey Giller 10 is a writer and photographer based in Ithaca, N.Y.