K. brevis blooms occur in the Gulf of Mexico almost every year, generally in late summer or early fall. A study of three red tide blooms that occurred in the 1970s and 1980s estimated losses from each to be between $15 million and $25 million. Coastal communities that rely on tourism lose millions of dollars when dead fish wash up on beaches or beachgoers experience eye and respiratory irritation, and shellfish-harvesting businesses lose income when shellfish beds are closed. People who consume shellfish contaminated with brevetoxins can suffer Neurotoxic Shellfish Poisoning.īlooms of K. Brevetoxins may also cause health problems in humans, including respiratory irritation when wave action breaks open cells and the toxins become airborne. K. brevis produces brevetoxins capable of killing fish, birds and other marine animals. Florida Youth Conservation Centers Network.Great Florida Birding and Wildlife Trail.Report injured, orphaned or dead manatees.Report fish kills, wildlife emergencies, sightings, etc.Brown tides are commonly seen in the northeast and mid-Atlantic U.S. Aureococcusis a spherical, non-motile species that has caused noticeable damage to the coastal ecosystems in which it occurs. Brown Tidesīrown tides are caused by the pelagophytes (another type of microalgae) such as Aureococcus anophagefferens. This results in habitat loss for marine fish, less oxygen and sunlight for other organisms and an ecosystem that is more vulnerable to extinction and invasions. When in bloom, macroalgae often outcompete seagrass and coral reefs. and Codium isthmocladum, which have caused serious damage to many coastal regions. Green tides can also be caused by macroalgae such as Enteromorpha spp. Green tides can be caused by Phaeocystis, which is a unicellular, photosynthetic algae found throughout the world. as well as Florida and the Gulf of Mexico (though regionally, they are often caused by different species).

This type of tide is very common on both the east and west coasts of the U.S. As a result, when there is a bloom of this dinoflagellate, the ocean will generally turn red. Most dinoflagellates, such as Alexandrium catenella, have this pigment. Red tides are caused by phytoplankton that have a reddish pigment called peridinin. Generally, there are three kinds of algal blooms that occur in our region: red, brown and green. Phytoplankton also have accessory pigments that allow them to use different wavelengths of sunlight for cellular growth and nourishment. In California, red tides generally occur between spring and early fall.Īll photosynthetic phytoplankton have chlorophyll as their primary pigment, which explains why researchers measure chlorophyll concentrations to figure out how much phytoplankton there are in a certain region. Some harmful blooms can even occur when the water is perfectly clear.Īlgal blooms are often called “red tides.” However, algal blooms are not always red and they really have nothing to do with the tides.Īlgal blooms are found all over the world in the U.S., they occur from Alaska to Florida and can last anywhere from a day to a few months depending on their resources. Therefore, water discoloration is not an accurate way to tell whether a bloom is toxic or dangerous. Visible algal blooms can be caused by different species, both harmful and non-harmful. However, harmful algal blooms can harm or kill marine animals, contaminate shellfish and threaten human life. Most algal blooms are natural and essential components of any marine ecosystem - and most are nontoxic. Other environmental factors can be temperature and salinity, which influence HABs differently but may help in determining the sources of blooms.Įach type of algae has its own preferences of environmental factors that is, the recipe changes depending on the species.Limited number of grazers or predators.Calm waters (low wind and circulation).In order for a bloom to occur, there has to be just the right “recipe” of environmental factors: Algal blooms occur when environmental conditions allow explosive growth of phytoplankton - a bloom - that can change the color of ocean water.

Algal bloom red tide algae