Alaska’s seasonal algal blooms are now one of the world’s longest-running marine ecosystems, with thousands of acres of fish, shellfish, and crustaceans found to live in the water.
But despite decades of efforts to control the algae, the blooms continue to be a cause of concern for environmentalists.
A new study published this week shows that a key component of the algae that gives rise to the bloom, called neonicotinoids, is also present in the environment.
And the researchers found that these chemicals are already being released into the water in large amounts.
The study, which was published in the journal Nature Climate Change, used water samples from two Alaska lakes and compared them with a similar region in Europe where no algal-plague events have occurred in the last three decades.
Researchers from the University of Bristol in England and the University College of London, which is a founding member of the Global Algal Network, looked at the algal activity in a large collection of lakes in Europe, where no events have been linked to the algos.
The researchers found a strong correlation between the abundance of neonic-treated water samples in the lakes and the number of fish found in the samples.
They also found that neonic treatment of water in these lakes was linked to higher levels of plankton and other plankton-eating organisms.
“We found that, on average, the plankton in these samples were larger than in the surrounding lakes,” said study co-author John Breslin, a senior scientist at the University’s department of fisheries and aquatic ecology.
“It was a bit like the plankbotch on the beach in the Caribbean.”
He added that the study is the first to show a link between neonic exposure and increased plankton activity.
The scientists also found higher levels in plankton found in water samples that were not treated with neonic pesticides.
“If we take the fact that you’re treating a water sample with neonics, and then the planktons are larger in the area, it can have a very significant effect on how much you are exposed to those chemicals,” Breslyn said.
“It can mean that the area of the lake where you are fishing is much more exposed to these chemicals.”
The researchers note that they did not find a correlation between neonics and fish kills.
The paper also found the presence of neonics in the waters of other regions in Europe that have been targeted by the algs.
The algal populations in these other regions, like the Baltic Sea, the Atlantic Ocean, and the Pacific Ocean, are believed to be much more sensitive to neonic exposures than the alga populations in the Arctic Ocean.
“What we’ve found in these two studies is that neonics are not the cause of the algaros, they’re a by-product of the environment that we’re dealing with,” Brellin said.
The algal ecosystems in Europe are not completely isolated from the rest of the planet.
“The algaras are really not isolated from other ecosystems,” Bretford said.
“So we’re not saying that algal infections are limited to the Arctic.
They’re a part of the ecosystem.”
But even as they are being driven by neonic poisoning, the effects of neics are also being felt in Alaska.
“The Alaskan algal situation is one of an international concern,” Bremford said, noting that a major challenge for scientists in this area is to determine whether the algloses can be mitigated through control of neicides, or by more intensive monitoring and treatment.