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Harmful Algal Blooms

"Sometimes tiny algae can cause big problems"
NOAA

Toxic Algal in Marine Waters are Changing Alaska's Marine Ecosystem

Much warmer than normal water and air temperatures continued along the Alaskan coastal areas in recent years, as part of the continuing increase in average global temperatures, and the specific result of an unusually persistent high pressure ridge that first developed in 2013 on the USA and Canadian west coasts.

The result was an anomalous area that came to be known as the “blob” – a large area in the Gulf of Alaska and Bering Sea where marine waters were as much as 12° C above normal. This passed the pivotal temperatures of 6° C-16° C for the growth of a number of harmful algal species including  Pseudo-nitzschia and Alexandrium.

Impacts in Alaska?

When filter feeders such as zooplankton, clams, oysters, mussels, and small fish eat algae they accumulate algal toxins in their tissues. The toxins are passed up the food chain to higher level predators such as fish, birds, marine mammals, and humans as they consume the contaminated organisms, causing illness and death. HABs can harm humans by negatively affecting commercial, recreational, and subsistence fisheries, and tourism, with big impacts on local economies and the livelihoods of coastal residents. High profile, clearly proven impacts include contaminated shellfish like clams and mussels and evidence is growing of wider spreading impacts including recent massive die-offs of seabirds like murres.

Related Resources and Stories

Tool: Alaska Seabird Die-off

Thousands of dead and dying murres have been washing up on beaches this year, from California to the Gulf of Alaska.