A Cyst in Time

WHOI researcher Kerry Norton uses fluorescence microscopy to identify and count dormant cysts of Alexandrium fundyense, the alga that produces a toxin that accumulates in shellfish and can cause paralytic shellfish poisoning in humans who consume them. In low numbers, the alga poses little danger; but in some years, the species undergoes a regional population explosion and creates a red tide or harmful algal bloom. WHOI scientists have developed a computer model that predicts the likelihood of a summer red tide based on counting the Alexandrium cysts in seafloor sediments the previous fall. This year, the group predicts a “moderate” red tide season in New England coastal waters.(Photo by Tom Kleindinst, Woods Hole Oceanographic Institution)