hi reader ,

Red tide is a phenomenon caused by algal blooms (Wikipedia definition) during which algae become so numerous that they discolor coastal waters (hence the name "red tide"). The algal bloom may also deplete oxygen in the waters and/or release toxins that may cause illness in humans and other animals.

Chemicals from farming, factories, sewage treatment plants and other sources can become dissolved in water on the land. This water, called runoff , eventually flows into the ocean and can cause algae to grow faster, leading to red tides.

examples of red tide include:

At least three species of dinoflagellates and one diatom species , golnuloaox

i hope this helps

thank you