New research from the Jackson School of Geosciences found an absence of permafrost under the seafloor along the coast of northeastern Alaska, according to a press release.
The finding countered the conventional idea that permafrost extended offshore in a gentle slope from the coast, project lead author Micaela Pedraza said. The beach and seafloor appeared to be ice-free for at least 65 feet, according to the press release.
“We saw an abrupt absence of ice, which resulted in unfrozen sediment,” Pedrazas said. “I think the biggest implication of our research is that now we have this potential pathway … for carbon to end up in the atmosphere.”
The team mapped the subsurface beneath the Kaktovik Lagoon over three years using a geophysical technique called electrical resistivity imaging, according to the press release. This technique injects an electrical current into the seafloor and measures how much each level of the subsurface resists the current, according to the study in ScienceAdvances.
Pedrazas said when the pores of the subsurface are filled with ice, as in permafrost, it resists the current.
Pedrazas said the coast analyzed in her study eroded at an average of 0.6 meters per year between 1947 to 2010, with a maximum of 4.5 meters lost per year.
In addition, the erosion could result in loss of cultural heritage items from the local Inupiat community, which are sometimes stored in underground ice cellars, Pedrazas said. The Inupiat Community of the Arctic Slope is a Regional Alaska Native tribal government, according to their website.
“The mission of ICAS is to exercise its sovereign rights and powers for the benefit of tribal members, to conserve and retain tribal lands and resources including subsistence and environmental issues,” according to the ICAS website.
Pedrazas said the erosion has led to damaged infrastructure, including the loss of the airport landing strip in the city of Kaktovik.
“Knowing that permafrost is thawing, that land is subsiding … that their village is essentially being pushed further inland is a source of constant preoccupation for them,” Pedrazas said. “So we wanted to understand really what's happening at this specific site.”
James McClelland, professor at the UT Marine Science Institute and co-author of the study, said the study alerts scientists that what's going on under the sediments beneath the coastal ocean and what's going on underneath the tundra near the coast is not separate. McClelland said one of the biggest challenges of studying the Arctic is a lack of understanding of how the ecosystem functions.
“Especially up there where climate change is rapidly altering how things are, we don't know what new is and what normal is,” McClelland said.
Arctic warming and rising sea levels have caused coastline collapse and permafrost degradation, which could lead to changes in the food web, according to a 2017 research paper published in Nature Climate Change.
McClelland said the big-picture questions about nutrient input are particularly relevant to the coastal Indigenous communities in the Arctic.
“Understanding better what supports the food webs there helps us understand how changes … could potentially alter the ecosystem function, including species that are particularly relevant to their subsistence lifestyle,” McClelland said.
