Due Friday, April 11 at midnight
Go through the various exercises and answer the questions.
First go to: http://www.smm.org/deadzone/top.html 1. Explore the “What is it?” tab.
What does it look like from space?
How big is it?
2. Explore the “What causes it” tab.
Go through steps 1 through 4 on the cartoon map. Start by clicking on the #1 and click on the “next step” tab until #4, then click on the “learn more” tab. Stop here and answer the questions below.
- What nutrients are the most responsible for causing dead zones?
- Where do the excess nutrients come from?
- How much of the US continent drains into the Mississippi river?
- Comment on potential financial implications of trying to reduce nutrient run off.
- Why doesn’t atmospheric oxygen help to oxygenate the deep waters of the Gulf of
4. Data Exercise
More Introduction to the problem:
If they can't swim, they die. Fish and shrimp are able to escape the suffocating grasp of the hypoxic (low-oxygen) waters in the Gulf of Mexico, but animals like clams, snails, and worms are trapped in the "dead zone," an area which grew larger than the state of
New Jersey in 2001 (approximately 8,000 square miles). It's a marine horror scene, and we should all take notice because it's happening in other coastal areas, too. More than half of the estuaries in the country experience oxygen depletion during the summer, and a third experience a complete loss of oxygen. The hypoxia in the Gulf, however, is the most dramatic case.
To date, scientists trace the cause of the problem to high levels of nutrients, particularly nitrogen. About two-thirds of the nation's harvested cropland and the treated sewage of
27% of the U.S. population empty into the Mississippi River, and eventually into the
Gulf. The nutrients discharged feed algal blooms in the spring and summer, which periodically die and sink to the bottom. Large amounts of oxygen are then consumed by the bacteria that decompose the dead algae. Sometimes, so much oxygen is consumed that there is not enough left in the water to sustain animal life. This condition persists
until an event such as a tropical storm or a cold front mixes the oxygen-depleted lower waters with the upper waters and brings relief.
Take a look at some of the data collected by scientists who have been monitoring the dead zone for many years as part of the Nutrient Enhanced Coastal Ocean Productivity