UNCW’s Dr. Michael Tift, a recent recipient of the university’s Rising Research Excellence Award, and Ph.D. student Anna Pearson were stationed in Patagonia, Chile for two and a half weeks to quarantine before embarking on their month-and-a-half journey to Antarctica on the Nathaniel B. Palmer, a large icebreaker research vessel.
Their three-year, more-than-half-a-million dollar research grant is made possible by the National Science Foundation.
Tift and Pearson are joined by Dr. Luis Huckstadt, UNCW adjunct professor and senior lecturer at the University of Exeter, Dr. Dan Costa from the University of California Santa Cruz, UCSC Ph.D. student Arina Favilla, and UNCW student Zaahir Santhanam.
The polar location is important to their research on climate change impacts.
“It's one of the areas that's experienced one of the fastest rates of warming in the world. And so that's particularly why we are going to the Western Antarctic Peninsula,” said Pearson.
They're studying these impacts through a sentinel species, animals who detect risks to humans, providing an advance warning of danger — in this case, the danger of warming seas.
“We do know that crabeater seals have a pretty exclusive diet of krill. And so that makes them a really great species in order to understand what's happening to the entire ecosystem in terms of climate change, and where krill species may be shifting in response to certain climate warming, as well as where the predators could be shifting in response to the krill shifts,” said Pearson.
Dr. Tift said these sentinel species are those that can be studied "to learn about multiple levels of health within other populations and/or the environment. Since they are top predators, their overall health can inform researchers about how their environment as a whole is functioning. If the environment has changed so much that it affects smaller organisms and conditions that impact the food of crabeater seals (e.g., krill), then they could see this in the health of the crabeater seals."
Tift said their name is a bit of a misnomer — scientists think it was a mistranslation.
“So crabeater seals, they don't actually eat crab, they eat krill, which is a crustacean. So they're like a small shrimp basically,” said Tift.
And there are millions of these seals, according to Tift, “Most of the earth’s population don’t know about crabeater seals because they really only exist down in Antarctica. Not many people get a chance to see them or even know about them.”
Tift and Pearson are building their work off of Dr. Costa and Dr. Huckstadt's research. They studied the health of the crabeater seals about 15 years ago.
“And so our job is to go down and try to repeat some of those measurements to see if there are any differences. We'll also be doing some health measurements in the animals trying to understand body condition, diet, just differences in mass, things like that,” said Tift.
While in Antarctica, the researchers are hoping to tag seals in order to figure out their migratory patterns. They’ll only have about five months worth of data because the tag falls off when the animals molt.
“It'll also transmit location so we can see sort of where the animals are going, and how much time they're spending traveling, foraging, things like that,” said Tift.
It’s Tift’s hypothesis that the crabeater seal populations are changing locations in Antarctica.
“The idea is that as the Western Arctic warms, it actually causes a lot of the animals potentially to want to move south where it's going to be colder, sort of closer to the South Pole,” said Tift.
According to Tift, that could also mean that they're having to forage deeper — or they're having to forage for a longer period of time.
Tift’s research on deep-diving mammals and CO
Tift and his team will also be studying the levels of carbon monoxide (CO) in these seals. His area of expertise is how high levels of the gas help protect these deep-diving marine mammals — and how this ability has implications for human health.
Related — CoastLine: Elephant Seal biology may reveal new medical uses for carbon monoxide
“Recent research has shown that small, low doses of carbon monoxide have fairly potent protective effects for cells and tissues. And the most promising protective effect is anti-inflammation or anti-apoptosis,” said Tift.
This part of the research focuses on marine mammals' ability to regulate blood flow, restricting it during deep dives.
If a cell gets injured, one’s body can ‘tag’ it to be destroyed, so that the body can make new cells. This is called apoptosis and it's usually a natural and controlled part of growth and development, but too much apoptosis or cell death going on could spell trouble for organ tissues.
This can happen during what is called ischemia-reperfusion events: ischemia is the restriction of blood flow, and reperfusion is restoring that blood flow. Apoptosis can be triggered during ischemia and continue during reperfusion, causing inflammation.
Enter CO, which can help to reduce this inflammation, which translates into potential treatments for those who have a stroke, heart attack, or organ transplant — all situations where blood flow is reduced, or stopped, and then restarted.
“And so carbon monoxide, in many cases is shown to reduce the amount of organ transplant rejection. But what's unique about these marine mammals, is that as of right now, they're the only species in the world that are known to have high levels of carbon monoxide maintained throughout their life. It's not natural for a human or lab animal to have high levels of carbon monoxide, even though they're showing us it’s protecting them,” said Tift.
The coolest part of this evolutionary trick, according to Tift, is that when a marine mammal dives "it will reduce blood flow to most organs like the spleen, liver, kidneys, and intestines so that they can maintain a constant flow of oxygenated blood to organs like the heart and brain, which requires a lot of oxygen."
And then when they get to the surface, these deep-diving mammals 'reperfuse' those tissues that had been cut off — that is, in ischemia — during the dive. And so these marine mammals are constantly going through ischemia-reperfusion events.
“And so we're wondering, is it an evolutionary advantage for them to keep permanent CO levels high in order to prevent injuries to their tissues? We don't know that yet. We're starting to get to those questions right now,” said Tift.
Tift said it’s important for the public to know — that the CO produced by cigarette smoke is not beneficial whatsoever.
“While cigarettes might deliver low to moderate amounts of CO, they also introduce a plethora of extremely harmful chemicals into the body which can have severely negative effects. The same is true for car exhaust,” said Tift.
Climate change impacts
Potential health benefits aside, Pearson and Tift ultimately hope their study of the seals will help show the extent to which climate change is occurring.
“Even though we don't see what's happening in Antarctica daily, I think this project will help us to really understand what we're doing and how it's impacting other species as well,” said Pearson.
Tift said that many scientists believe that the greatest threat to society is climate change.
“It's happening on a global scale. It's impacting animals all around the world. And for the most part, a lot of them can't keep up with the rate at which their environment is changing and that's unfortunate,” said Tift.
What’s most concerning is that those animals who live down in Antarctica are quickly losing their habitat of sea ice.
In April 2022, the Washington Post reported on a study that showed that about a third of all marine life could vanish within 300 years. Princeton University researchers Justin Penn and Curtis Deutsch published their findings in the journal Science.
In the article, the researchers pointed out that oceans are absorbing the excess carbon dioxide — thus depleting the oxygen in the water.
“And that will change the pH of the water making it more acidic,” said Tift, which will in turn begin to affect species like krill, the crabeater seals’ main food source.
The bigger picture of stopping the impact of climate change, according to Tift, needs to be driven by lawmakers to make decisions to stop carbon dioxide emissions in the atmosphere.
Tift and his team are continuing to build the scientific record of climate change impacts with this study of the seals.
“As scientists what we're trying to do on this trip, we're focusing on a few species, mostly crabeaters and their krill, and trying to understand how they're changing,” said Tift.
The researchers will spend the next month gathering data — then they’ll return in May 2023 to re-evaluate the crabeater seal populations.
Want to follow along on their journey to Antarctica?
Twitter: @uncwtiftlab @LuisHuckstadt
Instagram: @uncwtiftlab
*Editor's Note: This original article incorrectly identified the ship's name as Daniel D. Palmer. It's the Nathaniel B. Palmer. Dr. Tift also clarified some of the science behind CO — and the impacts of apoptosis and ischemia on marine mammal organs. He also further elucidated the impact of sentinel species. Moreover, CO is better defined as a gas rather than a chemical. This article reflects those updates.
