A National Ocean Service/National Center for Coastal Ocean Science Program
Phytoplankton Monitoring Network
Promoting a better understanding of harmful algal blooms by way of volunteer monitoring
Resources
Harmful Algal Blooms
Algae is seen everywhere because it creates the base of both marine and freshwater food webs. There are three specific classes of unicellular algae that produce the toxins which may cause many human health problems. Dinoflagellates, diatoms, and cyanobacteria are responsible for producing a variety of toxins. The known toxin producing species typically do not affect humans directly rather illness occurs through the consumption of seafood. There are five major human seafood poisoning syndromes: Amnesic Shellfish Poisoning (ASP), Ciguatera Fish Poisoning (CFP), Diarrhetic Shellfish Poisoning (DSP), Neurotoxic Shellfish Poisoning (NSP), and Paralytic Shellfish Poisoning (PSP). All of these except for ASP are caused by dinoflagellates. ASP is the only syndrome that is caused by a diatom. Most cyanobacterial toxins affect human health through drinking water contamination. U.S HAB Distribution Map (image | pdf)
Dinoflagellates, diatoms, and cyanobacteria exist all around the world and many do not cause any human health or similar types of problems. However, when the conditions are optimal (temperature, salinity, light intensity, nitrogen/phosphorus ratio, etc.) for a particular species, a plankton bloom can occur. A bloom is when an excess amount of a species is produced in one area. Some blooms can discolor the water because a species is found in such high abundance. Not all algal blooms are harmful. This section explores some of the different blooms that are caused by dinoflagellates and diatoms. Each section provides information on the species that causes the disease, the toxin that is produced, where the disease is found in the world, the symptoms humans face, other organisms that are affected, any treatments for humans, and current research that is occurring with each. Human Health Syndromes Table (image | pdf)
Toxic Diatom Blooms
- Pseudo-nitzschia spp.: Amnesic Shellfish Poisoning (ASP)
Toxic Dinoflagellate Blooms
- Alexandrium spp.: Paralytic Shellfish Poisoning (PSP)
- Dinophysis spp. and Prorocentrum spp.: Diarrhetic Shellfish Poisoning (DSP)
- Gambierdiscus toxicus: Ciguatera Fish Poisoning (CFP)
- Karenia brevis: Neurotoxic Shellfish Poisoning (NSP)
- Pfiesteria spp.: Possible Estuary Associated Syndrome (PEAS)
- Protoperidinium spp.: Azaspiracid Poisoning (AZP)
