Red tide

Red tide is a common name for a worldwide phenomenon known as an algae bloom (large concentrations of aquatic microorganisms—protozoa or unicellular algae) when it is caused by species of dinoflagellates and other organisms. These blooms can present a reddish appearance in the water column due to the high density of pigmented cells.

Causes

Red tides are caused by an increase in nutrients in the water, particularly phosphorus and nitrogen, and certain conditions of temperature and salinity. These conditions can result in the rapid growth of a single species of algae, known as a bloom. Some of these species produce toxins that can harm or kill marine life.

Effects

The effects of red tides include the death of marine life, human illness, and economic harm. The toxins produced by the algae can kill fish, shellfish, and marine mammals, and can also be harmful to humans if they eat contaminated seafood or inhale the toxins. The economic impact can be significant, as red tides can result in the closure of fisheries and beaches, and the loss of tourism revenue.

Prevention and control

Prevention and control of red tides is a complex issue. It involves reducing nutrient pollution, monitoring for the presence of harmful algae, and developing methods to control blooms once they occur. Some methods that have been used include the use of clay to bind the algae and sink them to the bottom, and the use of bacteria or viruses that can kill the algae.

See also

• Harmful algal bloom
• Dead zone (ecology)
• Eutrophication
• Water pollution

External links

• Woods Hole Oceanographic Institution: Red Tide
• CDC: Red Tide Frequently Asked Questions

Red tide Resources
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