This story was originally Appeared in he is not here is part of climate desk collaboration.
Dead fish were everywhere, dotting the coast near the town and extending to the surrounding coastline. The mass death of October 2021, when hundreds, perhaps thousands, of herring washed up has been seared into the minds of residents of Kotzebu, Alaska. “There was literally fish everywhere on the beach,” said Kikitagulschmiut elder and fisherman Bob Schaefer.
Despite the dramatic death, there was no apparent culprit. “We have no idea what caused it,” said Alex Whiting, environmental program director at Kotzebue Aboriginal Village. He wonders if the extinction is a symptom of a problem he’s been noticing for the past 15 years. It’s an outbreak of toxic cyanobacteria, also called blue-green algae, that’s becoming increasingly visible in the waters around this remote Alaskan town.
Kotzeb is located on the western coastline of Alaska, about 40 kilometers north of the Arctic Circle. Before the Russian explorer Otto von Kotzebue named the place in the 1800s, the area was called Kikitakurk, which means “almost like an island.” The two-kilometer-long settlement borders the Kotzebue Strait, a tributary of the Chukchi Sea, on one side and a lagoon on the other. Airplanes, boats and four-wheeled vehicles are the main means of transportation. The only way out of town is to circle around the lagoon and then back into town.
In the middle of town, the Alaska Mercantile Company sells everything from cereals to apples to bite-sized brownies, a staple of the 48 Southern states, but for many in town, the real grocery store is the ocean. Alaska Natives, who make up about three-quarters of the population of Cotzebu, pull hundreds of kilograms of food out of the ocean each year.
“We are people of the sea,” Schaefer tells me. It was a drizzly September morning in 2022, and the two of us were crammed into a tiny cabin on a Schaefer fishing boat in the middle of the day. We drive to a water quality monitor moored in Kotzebue Bay during the summer. On the bow, microbiological oceanographers Ajit Subramaniam of Columbia University in New York, Whiting, and Shaffer’s son Vince tuck their noses into upturned collars to keep out the chilly rain. We are coming together to gather a summer’s worth of information about the cyanobacteria that may be poisoning the fish that Schaefer and many others depend on.
huge colony of Algae are not new and are often beneficial. For example, in the spring, increased light and nutrient levels encourage phytoplankton to thrive, producing a microbial broth that feeds fish and invertebrates. But unlike many forms of algae, cyanobacteria can be dangerous. Some species can produce cyanotoxins that cause liver and neuropathy and even cancer in humans and other animals.
Many communities are contaminated with cyanobacteria. While many cyanobacteria can survive in marine environments, freshwater blooms tend to be more prominent, and their impact can spread to brackish waters when streams and rivers carry them to the sea. In East Africa, for example, blooms in Lake Victoria have been blamed for mass fish mortality. People can suffer too. In an extreme case, 26 of her patients died after being treated at a hemodialysis center in Brazil in 1996, and investigations found cyanotoxins in the clinic’s tap water. More often, exposed people experience fever, headache, or vomiting.
