Q. Human impact on the Earth’s environment is poignantly demonstrated in 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) examine cycling of oxygen in the natural marine ecosystem and how this cycle is upset during an algal bloom

b) choose 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.