Just a few years ago, the ocean seemed to be a good natural buffer for climate change. By absorbing carbon dioxide, it reduced the amount of greenhouse gasses in the atmosphere and reduced overall warming. Now, researchers like Scott Doney are rethinking to what extent this is still true.
Do the atmospheric benefits offset the damage to ocean ecosystems, the acidification of the ocean or damage to human seafood sources? Will the rate of CO2 absorption slow or stop, allowing more CO2 to remain in the atmosphere?
Doney is a researcher at the Woods Hole Oceanographic Institution and the University of Virginia. Last November, Clarivate Analytics released its listing of Highly Cited Researchers, and Doney’s work has put him on the list. Clarivate resources like the Web of Science point to a sampling of the work that has made him one of the world’s leading climate change scientists.
Tracing ocean circulation
Trained as a chemist, Doney began investigating environmental issues when he worked on a project using chemical tracers to investigate ocean circulation. He worked with an ocean physicist and chemist who had been using chlorofluorocarbons (CFCs) and tritium/helium isotopes to map ocean flow and discover how much human-released CO2 was getting into the ocean.
The tracers acted like a dye, which started at the surface and could be followed all the way into the ocean interior.
“Along the way, I realized, ‘well, I need to know more about ocean biology, because that also affects CO2, and then there is this whole question of ocean acidification,'” says Doney.
His interest was on acidification sparked by key lab experiments on the topic by colleagues in the late 1990s and early 2000s. He began studying ocean acidification, and his second paper on the topic was published in Scientific American, explaining the issue to the public.
Explaining these issues to the public has been a significant part of Doney’s career. He took a training program on communicating with the public when he was still working with helium isotopes. Now, understanding what information the public and stakeholders need to know actually guides some of his choices when pursuing science.
“I started to be more strategic in my science investments, the questions I was going to ask,” Doney says. “So, I’m still doing very critical basic science, but it’s being inspired more in terms of what the public needs to know and what decision-makers need to know.”
Rethinking the ocean’s role in climate change
Today, Doney works on two major questions regarding climate change and the oceans. The first is how the ocean carbon cycle affects climate change as a whole. The second is how the absorption of carbon into the oceans – also known as ocean acidification – affects ocean ecosystems.
Today, about a quarter of all human emissions of carbon are absorbed by the ocean. With less CO2 in the atmosphere, this means that climate change is happening significantly slower because of ocean absorption. This dynamic has been understood for a while, but Doney’s research attempts to understand how long it will continue.
The question is whether ocean uptake of carbon will continue fast enough to provide a mitigating effect on global warming. Doney works to answer that question using field observations and models. By integrating those two forms of research, he hopes to enhance our understanding of human influence on the global carbon cycle.
“Humans aren’t having a big influence yet on ocean uptake, but we think as the climate warms that the ocean will become less effective,” he notes.
Acidification and ocean ecosystems
Doney’s second area of research is how ocean acidification and climate change affect marine ecosystems. The chemistry of the ocean is changing, and its temperature is growing warmer. Doney hopes to predict how these changes will affect ocean life like plankton, and even travel up the food chain. His main tools, again, are field data, satellites and models.
In addition to global work, he focuses on two major regions. The first is the US northeast, where ocean ecosystem changes can have a major impact on humans. The second is Antarctica.
“[Ocean acidification] makes it harder for some plants and animals to grow, particularly things like shellfish,” says Doney. “So, we’ve been doing a lot of work trying to integrate the large-scale view with what might happen to the lobster industry or scallop industry or local water quality and recreational opportunities.”
His Antarctic work happens at the US Palmer Station on the Antarctic Peninsula, and looks at what is happening to the ecosystems as sea ice disappears and the glaciers melt. Antarctic life has adapted to live with sea ice, everything from plankton to whales.
Through his research, Doney has kept two priorities close to heart. The first is engaging in research he’s personally curious about, and the second is figuring out what other people need to know. People need to know how climate change could affect their food supply or livelihood, just as they need to know how human activity affects Antarctic whales. He also notes that scientific ideas change in sometimes-surprising ways.
“When I was a student, I was taught all about how the ocean would remove CO2 from the atmosphere, and this was considered a positive,” he notes. “It’s only been in the last ten years or so that [we’ve understood the affects of] CO2 acidifying the water. We knew that would happen, but we didn’t think it would have the large potential impacts on biological organisms.”