UofSC Professor: Man-made climate change is devastating ocean ecosystems – UofSC News & Events
Erin Meyer-Gutbrod studies the movement of right whales and reef fish in response to climate change
Posted on: September 28, 2021; Updated on: September 28, 2021
By Rose Cisneros and Bryan Gentry, [email protected], 803-576-7239
Warming oceans are pushing some marine populations out of their habitats and at risk, according to new research led by Erin Meyer-Gutbrod, a professor at the University of South Carolina.
The change in temperature affects creatures large and small, from the critically endangered North Atlantic right whale to more common fish whose habitats are losing oxygen. Meyer-Gutbrod this month published two research papers that examine changes in the oceans over the past 15 years and provide a caveat for those who manage waterways and fisheries.
By understanding how ocean dwellers will move with warming waters, we can more effectively conserve species important to the ecosystem and the economy.
Preserving our ecosystems and maintaining biodiversity impact everyone. Human well-being is intimately linked to the environment.
– Erin Meyer Gutbrod
Right whales move to find food
At 140,000 pounds and 52 feet long, the North Atlantic right whale is one of the largest creatures in the world. It’s twice the size of a humpback whale, but just under half the size of the blue whale.
But the species has long faced the dangers of human activity. In fact, it gets its name from being the “right” whale to hunt, according to the National Oceanic and Atmospheric Administration Fisheries.
Meyer-Gutbrod, assistant professor in the School of the Earth, Ocean and Environment, began studying the effects of climate change on right whales in the North Atlantic as a doctoral student at Cornell University. It is an attractive species to study because long-term monitoring provides a lot of historical data to compare and its endangered status means people are paying more attention to its findings.
“The United States and Canada maintain protection policies to reduce [human-caused]
impacts on the species, âshe said. âThis means that my research can have a direct impact on conservation and management. ”
And these tips couldn’t come at a better time. In the summer of 2017, the United States National Marine Fisheries Service discovered 17 dead right whales, most of which had died from being struck by vessels or entangled in fishing gear. Twelve have been found in the Gulf of St. Lawrence, hundreds of miles north of the whale’s normal summer feeding range in the Gulf of Maine.
Meyer-Gutbrod investigated why whales move. His discoveries, published in the journal Oceanography, trace the movement to a “regime change”, a prolonged change caused by high water temperatures.
What we are seeing are right whales reacting to climate change in their prey environment.
– Erin Meyer Gutbrod
Meyer-Gutbrod’s findings paint a grim picture for the right whale. She says a northward shift of the Gulf Stream has warmed the Gulf of Maine from below, causing a decline in the zooplankton that right whales eat.
When whales left their traditional feeding grounds in search of food, they left protected waters, causing more deadly ship strikes and entanglements in fishing gear.
âWhat we are seeing are right whales reacting to climate change in their prey environment,â Meyer-Gutbrod said. âAs they headed north for food in the Gulf of St. Lawrence, many people were killed by ship strikes or entanglements. in fishing gear, in large part because there was no protection policy in place in this unexpected habitat.
To compound the problem, lower food availability and disruption of feeding environments results in lower calving rates. Newborn calves are more likely to die earlier and more often from malnutrition.
Estimates indicate that less than 360 right whales remain. The population decline is so severe that right whales were elevated to the critically endangered species list in 2020.
But there is good news. Meyer-Gutbrod’s research identifies ways the United States and Canada can help protect right whales, such as monitoring ocean conditions and whale sightings to possibly predict changes in new right whale habitats. As whales move, protective regulations should evolve with them, she says.
Meyer-Gutbrod calls for swift action to adapt regulations to the movement of whales.
âCanada and the United States will need to adopt more aggressive management plans,â says Meyer-Gutbrod. âFailure to adopt such measures and significantly reduce the sources of human-induced mortality could lead to the extinction of the right whale population before the turn of the century. “
Fish move to find oxygen
Meyer-Gutbrod’s research is also exploring how a warming ocean affects underwater oxygen and the fish that depend on it.
His recent research published in Biology of global change, co-authored with a team of researchers at the University of California at Santa Barbara, reveals that ocean oxygen concentrations are declining. Lower oxygen levels push some fish species into shallower waters while dragging others deeper, which has ecological and economic ramifications.
When fish leave their normal feeding grounds, it disrupts all other populations that depend on these fish – and that includes us.
Their research is the first to track changes in the distribution of fish in one location while tracking oxygen decline over a 15-year period.
Fish can drown if there is not enough oxygen in the water. Thus, either they move to more oxygenated areas, or they risk dying from lack of oxygen. For some species, this means finding shallower waters, where atmospheric oxygen mixes with surface waters.
However, other research indicates that fish may need to move to deeper, cooler waters to avoid anthropogenic warming at the surface. When fish move up to avoid oxygen starvation and down to avoid warm water, it results in a compression of usable habitat.
âThe depth band they can occupy gets narrower and narrower over time,â Meyer-Gutbrod explains.
This habitat shrinkage results in overpopulation and could affect fishing practices.
âIf you throw your net in the water,â says Meyer-Gutbrod, âand you get a ton of fish – more than you’re used to – you might think, ‘Oh, that’s a good one. year for fish. Perhaps the population is recovering. But instead, it could be that all the fish are just squashed in a narrower area. You could change fishing regulations to increase fishing allocations because of this increase in landings. ”
Scientists do not yet know the consequences of this shrinking of the web. What they do know is that fish are forced out of their optimal habitat. And they are not alone.
Local impacts of climate change
Meyer-Gutbrod’s research is more than an esoteric look at the profound changes underwater and 1,500 miles away. It has impacts close to home.
For example, whale watchers often congregate on the coast of South Carolina to spot right whales during the breeding and calving season, meaning that the species’ decline would be felt right here in the ‘State of Palmetto.
With regard to fish, if the compressed habitat results in overfishing, it could affect the human food supply and the fishing economy. Despite different environments, humans, whales and fish inhabit an interconnected global ecosystem.
But there are ways to help.
âFind ways to reduce the carbon footprint in your life and in your community. Communicate with your politicians on protecting our vulnerable ecosystems and reducing human impacts.
âPreserving our ecosystems and maintaining biodiversity impacts everyone,â says Meyer-Gutbrod. âThe Earth’s biosphere provides services on which humans depend, including the production of oxygen and food. Human well-being is intimately linked to the environment.
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Subjects: Faculty, Research, College of Arts and Sciences