Programmed cell death, or self-induced cell mortality, is the subject of increasing attention and research efforts. All phytoplankton blooms decline for a variety of reasons - nutrient depletion, zooplankton grazing, virus infections, sedimentation - but programmed cell death as a means to bloom termination is a new concept, and one not well understood.

Dr. Deana Erdner, an NCCOS-sponsored researcher with the University of Texas -Austin, is investigating the role of programmed cell death in terminating harmful algal blooms of Alexandrium, a major source of human paralytic shellfish poisoning. To distinguish factors regulating bloom decline, Dr. Erdner and her colleagues are studying coastal salt marsh ponds on Cape Cod, Mass. with a history of Alexandrium blooms.

The research is pointing to the possibility of programmed cell death as a factor in bloom decline. Researchers are also investigating other indicators of bloom decline, such as release of damaging reactive oxygen (i.e., free radicals) and the development of sexual gametes - both produced during times of environmental stress. The study is enhancing scientists' understanding of the mechanisms of harmful algal bloom termination and the potential for human intervention.

For more information, contact Quay.Dortch@noaa.gov.