Originally this story Appeared on hakai and is part of the Climate desk cooperation.
Dead fish lay everywhere, lying on the beach near the city and extending to the surrounding coastline. The sheer magnitude of the October 2021 extinction, when hundreds, possibly thousands of herring washed ashore, is what remains with the residents of Kotzebue, Alaska. Fish were “literally everywhere on the beaches,” said Bob Schaeffer, a fisherman and elder of the Qikiqtaġruŋmiut tribe.
Despite the dramatic deaths, there was no clear culprit. “We have no idea what caused it,” said Alex Whiting, the environmental program director of the Kotzebue Indigenous Village. He wonders if the die-off was a symptom of a problem he’s been chasing for 15 years: blooms of toxic cyanobacteria, also known as blue-green algae, increasingly visible in the waters around this remote Alaskan town .
Kotzebue is located about 25 miles north of the Arctic Circle, on the west coast of Alaska. Before Russian explorer Otto von Kotzebue attached his name to the place in the 19th century, the region was called Qikiqtaġruk, meaning “place that is almost an island.” One side of the 2-kilometer-long settlement is bordered by Kotzebue Sound, an outcrop of the Chukchi Sea, and the other by a lagoon. Planes, boats and quadricycles are the main means of transportation. The only way out of town just goes around the lagoon before heading back in.
In the middle of town, the Alaska Commercial Company sells foods popular in the lower 48—from cereal to apples to two-bite brownies—but the ocean is the real grocery store for many people in the city. Alaska Natives, who make up about three-quarters of Kotzebue’s population, get hundreds of pounds of food from the sea each year.
“We’re ocean people,” Schaeffer tells me. The two of us are crammed into the small cabin of Schaeffer’s fishing boat in the still-light hours of a drizzly morning in September 2022. We head toward a water monitoring device that has been moored in Kotzebue Sound all summer. On the bow, Ajit Subramaniam, a microbial oceanographer from Columbia University, New York, Whiting, and Schaeffer’s son Vince have tucked their noses into stand-up collars to protect themselves from the cold rain. We’re all here to collect a summer’s worth of information about cyanobacteria potentially poisoning the fish upon which Schaeffer and many others depend.
Huge colonies of algae are nothing new and they are often beneficial. For example, in the spring, more light and nutrients cause phytoplankton to bloom, creating a microbial soup that feeds fish and invertebrates. But unlike many types of algae, cyanobacteria can be dangerous. Some species can produce cyanotoxins that cause liver or neurological damage, and perhaps even cancer, in humans and other animals.
Many communities are infected with cyanobacteria. While many cyanobacteria can survive in the marine environment, freshwater blooms attract more attention and their effects can spread to brackish environments when streams and rivers carry them out to sea. For example, in East Africa, flowers in Lake Victoria are held responsible for massive fish kills. People can suffer too: in an extreme case in 1996, 26 patients died after treatment at a Brazilian hemodialysis center, and tests found cyanotoxins in the clinic’s water supply. More often, people who are exposed experience fever, headache, or vomiting.
