Which protists cause red tides

The Pseudonitzchia species of algae, forms of diatoms, more commonly create red tides off the coast of California.

Some of these blooms can be harmless, because not all produce the toxin domoic acid. In contrast to dinoflagellates, which swim to access nutrients and light, diatoms float in the ocean and if nutrients abound, the algae bloom. If not enough nutrients are in the water, they die. Generally, these algae bloom in spring and summer, though the more toxic blooms often occur during the spring. Alexandrium species are also found in California, first discovered there in after an outbreak of paralytic shellfish poisoning.

The neurotoxins produced by harmful algae blooms can cause massive fish kills , with dead fish washing up on shores by the thousands. The toxin works its way through the food web, with other species preying on the sick fish. Die-offs of many marine species, like whales and sea turtles , have been linked to red tides. The toxins can even produce a foam that causes seabirds to lose the waterproofing on their feathers , resulting in their death.

In Florida, manatees can be affected by brevotoxin, so much so that it can lead to respiratory problems or even death. People can be sickened from the toxins in the water or in tainted shellfish. Climate change complicates the frequency and occurrence of red tides. Wind and temperature are expected to increase with a warming planet. With more wind stirring up nutrients, dinoflagellates can get food easier.

But diatoms prefer calmer conditions. Scientists predict that climate change will increase the frequency and intensity of hurricanes , potentially moving blooms to new locations. In Florida, a red tide lasted for 17 months after big hurricanes blew through in and And in after Hurricane Irma, another giant red-tide imperiled the state.

Additionally, more nutrients, running into the ocean from excess fertilizer on farms or lawns, can contribute to blooms. Treatments of aluminum sulfate are sometimes used to fight algal blooms in small lakes or canals, but is not effective in the much larger ocean.

In the s, scientists tried using copper sulfate. That killed the algae, but also everything else in the water. Stumpf and a team of scientists have created red tide forecasts that are released biweekly to let people know how safe an area in Florida and elsewhere in the Gulf of Mexico is for recreation. The forecasts take advantage of satellite images to estimate the size and impact of a bloom.

A miniature microscope, the HABscope , , attaches to a smartphone and allows a user to capture short videos of water samples collected from different locations in Florida. Counting the number of microalgae cells in the water sample lets scientists determine the risk or severity of a bloom. In the Gulf of Maine, crews in the late fall collect sediment samples to count the number of Alexandrium cysts. They incorporate that level into biological models to predict the number that will survive until the next season.

Then, scientists combine that predicted number with salinity and ocean current data in physical models to help forecast how bad a bloom will be in the next year. Usually if they find a lot of cysts, the Gulf of Maine will have a larger bloom. Scientists at the National Ocean Service have been monitoring and studying this phenomenon for a number of years to determine how to detect and forecast the location of the blooms.

The goal is to give communities advance warnings so they can adequately plan for and deal with the adverse environmental and health effects associated with these 'red-tide' events. Home Ocean Facts What is a red tide? What is a red tide?

A "red tide" is a common term used for a harmful algal bloom. Search Our Facts. They have two whip-like appendages called flagella. They can use these flagella to swim and orient themselves. Some dinoflagellates, like those that cause red tides, can produce toxins.

Most dinoflagellates live in salt water. The species of dinoflagellate that causes red tide blooms in Florida is Karenia brevis. When conditions are just right, dinoflagellates can reproduce rapidly. Their main way of doing this is to divide into two, by a process called mitosis.

Thus the population can quickly double, and double again, and so on. When there is a higher than normal amount of microscopic plant-like organisms in a water sample, this is referred to as a bloom. Blooms can be caused by planktonic algae, or by dinoflagellates. Scientists do not know what causes red tide blooms.

Florida red tide blooms typically form miles offshore in the Gulf of Mexico, often off southwest Florida. The blooms often drift close to shore, where nutrient runoff from land may prolong the duration of the red tide event. These loggerhead sea turtle hatchlings washed up on Marineland Beach during the red tide event.