Natural Phenomenon - Red Tides

A common natural phenomenon that is not completely understood is red tide. Red tides are also known as toxic algae blooms because that is the cause of the tides. Red tides occur when microscopic algae and phytoplankton become so densely populated that the pigments they release are visible without a microscope. The name Red Tide is misleading for a couple of reasons. First, Red Tide has nothing to do with the tide at all. The growth of these algae is not affected by the tidal cycle. Second, the pigments of the algae and phytoplankton that cause red tides do not always have to be red. In fact they can also be orange, brown and sometimes green. The accurate name for red tides is actually HAB or harmful algal bloom. Another false fact about red tides is that the algae and phytoplankton are toxic, that is not the case. In fact these organisms are essential to the ocean’s food web and are very valuable to the environment. The pigment that the algae or plankton releases is the toxic element. Red tides or HABs can be triggered by nutrient rich water mixed with prime temperatures and conditions for growth and reproduction of these single celled micro -organisms. Red tides are in fact a growing threat to most coastal water. Red tides can be so harmful those scientists have gone as far to call HABs, marine bio-toxins. Red Tides negatively influence both humans and nature alike.

Red Tides have many negative effects on the environment. Red Tides or HABs can harm many marine organisms. They can kill anything from a simple plant to a very large humpback whale. It is true that algae and phytoplankton are at the base of the food web in the marine environment. They are essential to the survival of many marine animals that depend on algae and plankton for nutrients. However, when these toxic blooms occur, these once essential micro-organisms become like poison to their predators and the effects are catastrophic. These HABs are just harmful to marine life if they are ingested, they can also become so dense that they can actually suffocate other organisms. These algae and their pigments do not necessarily kill directly. Everyday organisms compete for dissolved oxygen and other nutrients in the water, when a bloom occurs the increase in organisms is exponential. Not only are resources being used at an increased rate but also decomposition and waste products in the water are also increased. Some species of these algae and phytoplankton actually carry toxins in their pigments. These toxins are neurotoxins that will harm and destroy normal nerve function. The toxins are not found in all red tides but they are often the cause of shellfish and larger organisms perishing. The Red Tides have many negative effects that affect the marine life and their environment.

Red tides do not only affect nature negatively but they also affect humans. These tides can affect humans both directly and indirectly. Humans are directly affected because it is true that some of the toxins released in the pigments of the algae and plankton can be harmful. Especially during a very dense bloom of algae, these toxins would be in high concentration and have the potential to be fatal even to humans. Humans are affected indirectly through our food resources as well as our source of economy. Because the algae invade the habitats of many organisms that are caught and eaten, many companies and restaurants are affected greatly by Red Tides. Shellfish and other fish are often taken off the market when a Red Tide occurs due to that fact that some types of algae are toxic. If the mussel or clam or even bigger fish, like haddock, ate the algae they could carry the toxin and harm the person who ate it. Also beaches are closed in an event of a HAB. Swimming is prohibited and even boating is discouraged. Red Tides have caused millions of dollars in damages. When beaches are closed, shell fishing and fishing halted, along with the closure of ports, Red Tides can prove to be extremely harmful to the economy. Red Tides are harmful to humans in many ways, whether directly or indirectly.

Scientists have been studying red tides all over the world. As of now, it is still impossible to predict or control these HABs. Scientists are trying to understand the cause of these red tides in order to create a solution. Knowledge about this phenomenon and its consequences will help to reduce the effects on humans. In the future, it may be possible to end these destructive tides.


Works Cited
Anderson, Don. "Toxic Blooms: Understanding Red Tides." Toxic Blooms: a seminar. Woods Hole Oceanographic Institution. 9 Oct. 2008 .
Collins, Jocelyn, comp. "Red Tide and Shellfish Poisoning." Red Tide and Shellfish Poisoning. 11 May 2006. 9 Oct. 2008 .
"Harmful Algae and Red Tides." Woods Hole Oceanographic Institution. Woods Hole Oceanographic Institution. 9 Oct. 2008 .

Picture Credits:
Red Tide

Shellfish affected by Red Tide