The fresher the water, the more toxic the algae

Changes in salinity may explain why red tide algae in the Gulf of Mexico becomes toxic as it moves onshore, killing marine life and posing health hazards to humans.

Red tide refers to the periodic blooms of microscopic algae that usually crop up in late summer or early fall throughout the Gulf Coast states.

Texas A&M researchers have found that as red tides move onshore and mix with fresher water, cells must adjust rapidly to the change in salinity.

As they adjust, brevetoxins—a collection of potent neurotoxins that cause gastrointenstinal and neurological problems in other organisms—within the cell increase to allow them to keep their water and salt content in balance more efficiently.

Read more at Proceedings of the National Academy of Sciences