Now let's talk about the toxic variety that are known more for their adverse effects rather than their role in the functioning of the ecosystem at large. The toxic phytoplankton, along with some of the nontoxic species, often grow in such large numbers that they form blooms , or population explosions of these tiny cells. Some blooms can discolor the seawater, and some are bioluminescent, producing a mystifying light that is visible in the water at night. Blooms can last from days to months - and sometimes longer than a year. They occur in waters all over the globe, and have been called red tides, brown tides or yellow tides.
Many blooms recur in some areas more than others.
This tiny plant is especially notorious along the Florida Gulf coast, often showing up in the late summer or early fall months. During a bloom, the cells divide within a few hours to a few days, and the population doubles every time. An initial G. breve population of 700 cells would grow to about 10,000 within one week, which is enough cells to cover a one-inch line. In other words, if the environmental conditions are right, and the cell is at the right stage of the life cycle, you can get a bloom. In the Gulf of Maine, blooms occur where water from coastal currents and a host of rivers come together.