[USA] The water began turning a barely perceptible brownish-green in early May, a sign that algae were present and growing in the waters of Monterey Bay. By the end of month, Raphael Kudela, a professor of ocean sciences at the University of California, Santa Cruz, and his team, who run a regional algae monitoring project, were measuring some of the highest levels of the neurotoxin domoic acid ever observed in the region.
Although domoic acid, produced by marine diatoms of the genus Pseudo-nitzschia, is a naturally occurring toxin, during a toxic algal bloom, it accumulates at dangerous levels in shellfish and small fish like sardines and anchovies, which are then eaten by larger marine creatures and humans. Contaminated seafood can cause nausea and vomiting in people. At high levels, the toxin can cause brain damage, memory loss and even death.
Today, the algae bloom observed in Monterey Bay waters has morphed into what some researchers suspect could be the largest ever recorded, stretching from central California all the way up to Alaska. Currently, the bloom is estimated at 40 miles wide and goes 650 feet deep into the Pacific Ocean.
“It’s a pretty massive bloom,” said Kudela, who runs the regional monitoring project with funding from the National Oceanic and Atmospheric Administration’s Ecology and Oceanography of Harmful Algal Blooms program.
“This event may be related to the unusually warm water conditions we’ve been having, and this year that warm water has spread all along the West Coast, from Washington to southern California,” he said in a June blog post on the university’s news site.
Algae blooms—which can occur in fresh and ocean waters and typically consist of a buildup of microscopic phytoplankton species of algae—are normal occurrences. However, increasingly, scientists have observed an uptick in harmful algal blooms, which produce natural toxins such as domoic acid and can lead to shellfish poisonings and large marine species mortality events.
A view of the future?
“Whether this bloom is providing a window of things to come for the future, and a world that we can envision under climate change, I think that’s a distinct possibility,” Vera Trainer, a research scientist with the Northwest Fisheries Science Center in Seattle told Capital Public Radio last week.
In mid-June, a team of NOAA biologists began monitoring the massive algal bloom in conjunction with normal surveying work the researchers carry out to assess West Coast sardine and hake populations from Mexico to Vancouver Island.
Over the course of four trips, researchers on the Bell M. Shimada, a NOAA research vessel, will collect water and algae samples, measure water temperatures and test small fish that feed on plankton. Typically, toxic algae blooms disappear in a matter of weeks, but Trainer said this one may not recede until this fall, when the ocean begins moving again. Part of what this bloom is thriving on are unusually still, warm Pacific waters.
“The fact that we’re seeing multiple toxins at the same time, we’re seeing high levels of domoic acid, and we’re seeing a coastwide bloom—those are indications that this is unprecedented,” she said.
View original article at: Massive Toxic Algae Blooms May Prove a Sign of Climate Change to Come