For four decades, biologist George Divoky has spent summer camped out on an Arctic island, monitoring the seabirds that nest there and how they are faring in the fast-changing conditions of the far north.
This year, the results were striking.
"This year was very, very depressing," said Divoky, who spoke Wednesday at an ocean science conference in Anchorage, Oceans 17.
A colony of black guillemots that had 220 breeding pairs around 1990 was down to 85 pairs this year, he said. Hatch failures were widespread, with a success rate of 0.5 chicks per nest instead of the 1.1-per-nest rate needed to maintain the colony. And adult birds going to the sea for food were foraging in waters that were "crazy warm" and picking up a subarctic species called sandlance that appeared to be less nutritious than the arctic cod that used to make up most of their diet.
"As soon as they hatched, there was something strange happening because the birds started bringing in sandlance," he said.
Divoky's focus of study is Cooper Island, a speck in the Beaufort Sea about 25 miles east of Utqiagvik (formerly Barrow). He has been traveling there annually since the mid-1970s, camping out and studying the black guillemots up close, monitoring their changes through the years.
That put him, by serendipity, in position to monitor decades of Arctic climate warming.
In Divoky's first years on the island, warming appeared to be good for the guillemot colony there. From the 1970s through the late 1980s, Cooper Island became an increasingly attractive place for guillemots to nest, and the colony grew, Divoky's detailed records show.
But the story in recent decades has been one of decline.
The water temperature shifts started showing up in the late 1990s, and with it came a decline in the arctic cod that used to make up 95 percent of the guillemots' diets, he has reported. In the 2003-12 period, starvation rates for nestlings were five times higher than they were during Divoky's first decade of annual summer visits to Cooper Island, his research shows.
Declines in the Cooper Island guillemot colony have largely tracked with declines in Arctic sea ice, Divoky said in his presentation to the conference.
This year's minimum sea ice extent, measured at the end of the melt season last week, was not extraordinarily low, the National Snow and Ice Data Center reported. It was the eighth lowest on record, but part of a string of 11 consecutive sea-ice minimums that have been the 11 lowest since satellite records began in 1979, the Colorado-based center reported.
But sea ice melt – and warmup of open waters that were exposed – was more dramatic this year in the Beaufort and Chukchi seas than in other parts of the Arctic, the center reported.
That is consistent with what Divoky saw this year.
"Everything that was going on this year, there wasn't one good thing that happened in the breeding season," he said.