Sign of the Times

A sign stands sentinel in Nauset Estuary on Cape Cod, warning that the estuary is closed because of red tide. Annual springtime red tides, a type of harmful algal bloom, develop in the estuary from the germination of algal cysts found in the sediments. Shellfish consume the algae and accumulate a toxin in their tissues that can sicken people who consume them. WHOI biologist Don Anderson and others in his lab are studying whether cycts buried by re-suspended sediments are less likely to germinate, lessening the severity of the blooms. (Photo by Dave Kulis, Woods Hole Oceanographic Institution)