Human impact on the Earth's environment is poignantly demonstrated in the Mississippi River drainage into the Gulf of Mexico. Every spring, high levels of nitrogen and phosphorous wash into the river from the Midwestern United States farming region and into the northern Gulf. These nutrients supply a huge algal bloom at the water surface creating a dangerously destructive hypoxia that all but destroys the marine ecosystem.
a) Discuss the cycling of oxygen in the natural marine ecosystem and how this cycle is upset during an algal bloom.
b) Pick two organisms from two different trophic levels in the marine ecosystem and explain the impact of the algal bloom on their ecology.
c) It has been suggested that the hypoxic conditions in the Gulf might be contributing to an increased number of shark attacks along the Texas coast. Explain the thinking behind this suggestion.
How does an algal bloom form? As the nutrient rich waters flow into the Gulf of Mexico, algae (phytoplankton) growth is increased tremendously. Of course, as the algae thrive, other plants die. This leads to a significant amount of dead organic tissue in the waters. This dead organic plant material becomes "food" for the decomposers such as bacteria. It is the metabolism of this dead organic matter by the bacteria that leads to the oxygen depletion. Bacteria require oxygen for metabolism. ...
In about 340 words, this response discusses the topic of algal blooms and how this causes interference for some of the organisms in an ecosystem.