Phytoplankton Monitoring Network



Phytoplankton, or algae, are normal components of all aquatic environments, creating the base of both marine and freshwater food webs. When phytoplankton bloom in significant numbers and produce biotoxins, these events are termed harmful algal blooms or HABs.

HABs represent a present and growing threat to virtually all U.S. coastal waters, where their impacts range from devastating economic effects to public health risks to ecosystem alterations. Often referred to collectively as "red tides,” HABs are most often of concern because of the extremely potent toxins they produce. When HAB toxins accumulate in marine animals they lead to closures of commercial and recreational fisheries, mass mortalities of birds, fish, and marine mammals, and human illness or death in extreme cases.

algal bloom dynamics

Algal Bloom Dynamics

Most algal blooms seem to appear from “nowhere.” From the Northwest Fisheries Science Center’s HABs Program, learn the basic biology about how algae grow and what stops algal growth. Watch a short video on algal growth and learn about algal bloom initiation and bloom movement.

fish kill: credit Brazosports

Harmful Algae

A small percentage of algal species produce potent toxins which cause illness or death in humans and marine organisms - fish, seabirds, manatees, sea lions, turtles, and dolphins are some commonly affected animals. Other types of harmful algae are nontoxic to humans but cause harm to fish and invertebrates. [more]

hab sign

Human Health Syndromes

There are three specific classes of unicellular algae that produce the toxins which cause most human health problems: dinoflagellates, diatoms, and cyanobacteria. The known toxin producing species typically do not affect human health directly, but rather illness occurs through the consumption of seafood or through the contamination of drinking water. [more]

hab economic impacts

HAB Economic Impacts

All U.S. coastal states have experienced HABs over the last decade. HABs can adversely affect not only the health of people and marine organisms, but also the "health" of local and regional economies. A recent conservative assessment estimates that HABs occuring in marine waters alone have an average annual impact of $82 million dollars in the U.S.

harmful algae

HAB Links

Websites to visit to learn more about Harmful Algal Blooms (HABs), HAB economic impacts, current HAB research and human health syndromes related to marine toxins. [more]