A red tide is one type of harmful algal bloom. Blooms occur when colonies of algae--simple ocean plants that live in the sea--grow out of control while producing toxic or harmful effects on people, fish, shellfish, marine mammals and birds.

Harmful algal blooms (HABs) can occur in fresh, marine (salt), and brackish (a mixture of fresh and salt) water bodies around the world. They are caused by diverse organisms, including toxic and noxious phytoplankton, cyanobacteria, benthic algae, and macroalgae.

Red tide is also sometimes used to describe harmful algal blooms on the northeast coast of the United States, particularly in the Gulf of Maine. This type of bloom is caused by another species of dinoflagellate known as Alexandrium fundyense .

2025年1月2日 · The name “red tide” comes from the reddish-brown color that the water takes on when these algae bloom. Red tide can occur in both saltwater and freshwater environments, but it is most commonly associated with coastal areas.

2023年3月16日 · Red tides are a type of harmful algal bloom, and they occur worldwide. There are over 300 species of red tide, and within the United States, these blooms appear in three main coastal areas,...

Some algae species, like the dinoflagellate Karenia brevis, color the ocean surface a deep red, inspiring the name “red tide.” But not all red tides are red and not all of them even become dense enough to color the water. There are also “brown tides” which can be damaging as well.

2016年4月27日 · Many people use the term “red tide” to refer to harmful algal blooms, but not all HABs turn the water red. Blooms may appear in a variety of colors depending on the species of algae involved – and some HABs have no color at all.

Red tide in Florida and Texas is caused by the rapid growth of a microscopic algae called Karenia brevis. When large amounts of this algae are present, it can cause a harmful algal bloom (HAB) that can be seen from space.

What is a “red tide”? “Red tide” is a general term that is used to describe an increase or “bloom” of toxin-producing microorganisms (algae) that can cause water to have a reddish color. Red tide is one type of what is referred to as a harmful algae bloom or HAB.

2020年9月10日 · A “red tide” of blooming algae (the dinoflagellate Noctiluca scintillans) stretched more than 20 miles along the coast near LaJolla, California, in spring 1995. Such massive blooms can harm human health, coastal economies, and marine ecosystems.