Virtually every coastal country in the world is affected by harmful algal blooms (HABs).  This diverse array of phenomena includes blooms of toxic, microscopic algae that lead to illness and death in humans, fish, seabirds, marine mammals, and other oceanic life.  There are also non-toxic HABs that cause damage to ecosystems, fisheries resources, and recreational facilities, often due to the sheer biomass of the accumulated algae. The term “HAB” also applies to non-toxic macroalgae (seaweeds), which can cause major ecological impacts such as the displacement of indigenous species, habitat alteration and oxygen depletion in bottom waters.  

Few would argue that the number of toxic blooms, the economic losses from them, the types of resources affected, and the number of toxins and toxic species have all increased dramatically in recent years throughout the world.  Disagreement only arises with respect to the reasons for this expansion.  

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Last updated: February 25, 2016