Algae are microscopic organisms that can be found in coastal waters near the surface of the water and are major producers of oxygen and food for many of the animals that live in coastal waters. When environmental conditions are favorable, these cells may multiply rapidly and form high numbers of cells resulting in an algal bloom. A bloom often results in a color change in the water. Algal blooms vary color. However, the most common ones are red or brown. These blooms are commonly called red or brown tides. Most algal blooms are not harmful but some can harm fish, humans, and other animals like birds and marine mammals. These are known as Harmful Algal Blooms (H.A.B.).
Blooms can occur as a result of numerous of reasons. Two common causes are
nutrient enrichment and warm waters. Nutrient enrichment of water is often the result of pollution
from urban and agricultural runoff from farms, pesticides, stagnant water, and dumping sewage into the water. Water temperature
has also been related to the occurrence of algal blooms, with
unusually warm water being conducive to blooms.
Ways to prevent harmful algal blooms include stricter sewage dumping laws and managing runoff from cities and rural life.
An example of harmful algal blooms is the Dead Zone in the Gulf of Mexico. The Gulf of Mexico hypoxic zone is a seasonal phenomena
occurring in the northern Gulf of Mexico, from the mouth of the Mississippi
River to beyond the Texas border. It's referred to
as the Gulf of Mexico Dead Zone because oxygen levels within the zone
are too low to support marine life. The Dead Zone was first recorded
in the early 1970's. At first, it occurred every two to three years, but
now occurs annually. In the summer of 1999 the Dead Zone reached
its peak, stretching about 7,728 square miles in the Gulf of Mexico. Because of this increased numbers of blooms, fishing profits decreased, hurting the local and national economy. Many blooms can't be prevented, however they can be minimized by taking precise measures to slow the rate of pollution entering the ocean.
The Dead Zone
The Dead Zone
- Victoria Mehlhaff -