For 10 years, Princeton University in New Jersey has been leading a team of scientists on a project to put sensors in the ocean at the south end of the world, considered one of the planet's leading climate change hotspots, with a special focus on the waters that ring Antarctica.
Now, it's the La Jolla-based Scripps Institution of Oceanography's turn.
Under the leadership of Scripps physical oceanographer Lynne Talley, SIO will continue the Southern Ocean Carbon and Climate Observations and Modeling project for the next three years.
The new phase of SOCCOM, known as SOCCOM3, was funded by the National Science Foundation and the National Oceanic and Atmospheric Administration. Collaborators include the University of Washington, Monterey Bay Aquarium Research Institute, University of Arizona, University of Hawaii at Mānoa and Rutgers University.
When the project started, "the whole Southern Ocean [also known as the Antarctic Ocean] was our area of interest -- its temperature changes and how it exchanges carbon with the atmosphere," Talley said. "Carbon in that ocean had not been studied well, because in order to study it, you need more specialized measurements than a thermometer. We knew from modeling that the Southern Ocean is an important player in the carbon exchange system. But we had not been able to quantify that and nail down all the processes that affect it."
So the scientists developed and deployed 4,000 sensors -- "like satellites we see in the sky, but in the ocean" -- to measure temperature and acidity caused by carbon absorption. They record temperature and acidity readings every 10 days.
One thing that has proved hard to study until now has been sea ice and the water beneath it.
"We had practically no winter data for obvious reasons," Talley said with a laugh. "But we had a lot of breakthroughs in 10 years and they have been important in improving our climate modeling.
"On the carbon side, our big breakthrough is that once we were able to deploy the sensors [and have them there in winter], we now have measurements for this area. We're looking at how the carbon exchange is working, heat in the sea ice regions and how it affects the ecosystems."
One of the areas being looked at is Thwaites Glacier, an enormous Antarctic ice mass that is the widest glacier in the world, with an area of 74,000 square miles (larger than Florida) and thickness of 2,600 to 3,900 feet.
It is known as the "Doomsday Glacier" because if it should melt completely, it could cause over two feet of global sea-level rise.
"That's not going to happen," Talley said, but the glacier is melting and the team is looking at how quickly it is losing mass based on ocean temperatures.
"The first six years of SOCCOM got us in the water," Talley said. "After four more years, we had been through two natural El Niño southern oscillation cycles and the start of a major decline in Antarctic sea ice. Now we are starting to detect penetration of fossil-fuel carbon into the ocean, changes in ocean heat and possibly greening."
According to researchers, greener ocean waters indicate the presence of ecosystems, mainly phytoplankton, that use their green pigment to harvest sunlight, which they use to capture carbon dioxide from the atmosphere and convert it into sugars.
Going forward under Talley's direction, "we hope to start detecting trends. Trends are hard to detect in the ocean because seasonal changes are so big. You need to measure long enough, and that is what we are aiming for. When this study is done, we'll have had 13 years of data and new tools."
The hope, she added, is for the study to never be done. "With three more years, it means we have a chance to turn this into a permanent system," she said. "In this process, we have demonstrated it is possible to have a global array measuring carbon and have that in perpetuity."
This next phase of the project, according to SIO, also emphasizes what is known as the biological pump, during which photosynthesis close to the ocean surface uses carbon dioxide to make organic carbon. Much of that carbon is recycled in the upper ocean, but some of what sinks out of the surface reaches the ocean floor and is buried in the sediment, storing carbon that was once in the atmosphere. ♦