1. The Gulf of Mexico’s Hypoxic Zone
Group Members:
Jennie Biewald
Annie Rossetti
Joseph Stevens
Wei Cheih Wong

2. Dead Zone: Background
Occurs in the deepest part of the water where the oxygen levels have fallen below 2 parts per million (the amount of DO needed to survive)
The dead zone is one of the largest hypoxic zones in the world.

3. Dead Zone: Background cont…
Kills all oxygen-dependent sea creatures within its zone
In 2005, it was predicted that the dead zone was approximately 4,564 square miles, however it has reached a maximum of 7,000 square miles

4. Eutrophication
Eutrophication is the process by which dead organisms are broken down by bacteria
This process uses dissolved oxygen in the water
If the dissolved oxygen drops below 2 ppm then other organisms may flee from the area or suffocate

5. Eutrophication
This area becomes hypoxic and is usually called a dead zone
Dead zones are usually caused by either large scale death in an isolated area such as a poisoned pond
Also caused by large amounts of plant matter dying because of high levels of nutrient influx

6. Side Effects
Marine animals such as starfish, sea urchins and crabs which cannot move quick enough will most likely die
This can cause the added problem with jellyfish
Jellyfish can survive very low oxygen levels and can fill up the empty area

7. Jelly Fish
Since jellyfish can not be eaten they are of no economic value
They also affect tourism because who wants to swim with a smack of stinging jellyfish
This is a serious problem in the Black Sea

8. Jelly Fish In the Black Sea jellyfish began to breed rapidly
They eventually reached 1 billion tons of comb jellyfish
This is more than the combined weight of the entire worlds fish catch
Jellyfish have no economic value

9. Dead Zone: History
1950: First reports of “dead” or lifeless zones off the coast of Mexico by shrimp trawlers.
1970: Gulf of Mexico’s increasing hypoxic zone is finally investigated by scientists

10. Dead Zone: History
1985: Scientists begin tracking the size and timing of the Dead Zone
: Dead zone increases from just over 4,000 square feet to a outstanding 7,000 square feet due to floods.

11. Fertilizer Use
Fertilizer use has increased significantly since the 1950’s
The Green Revolution in the 60’s and 70’s caused larger amounts of fertilizer use in the Mississippi Basin

12. Fertilizer Use

13. Nitrogen and Phosphorous
Long lived
Is the limiting factor in the oceans
Phosphorous:
Short lived
Is limiting factor in freshwater
Any policy to combat both fresh and sea water eutrophication must address both elements

14. Nitrogen

15. Source of Nitrogen in the Mississippi Basin
Soil depletion – 31%
Commercial fertilizer – 31%
Legume – 21%
Atmospheric deposition – 10%
Manure – 6 %
Municipal and Industrial – 1%

16. Size of Dead Zone The size of dead zone was insignificant during 1988
and 1989 as great droughts hit the Midwest.

17. Freshwater
The chemical makeup of fresh and salt water is very different
Freshwater contains nitrates so any increase in nitrogen will have little effect
Freshwater though lacks phosphates so an increase in phosphorous will have severe consequences on algae

18. Saltwater
By the time the fertilizers make it to the ocean the phosphorous has already been used
The nitrogen on the other hand is long lived and not needed in freshwater systems

19. Land Use
The significant change in land use in the last 70 years has had an impact on the Gulf of Mexico.
Missouri River Basin has had hundreds of thousands of acres of forests and wetlands ( acres) replaced with agriculture activity.

20. Land Use
The loss wetlands has a profound impact on the nitrogen load as wetlands trap nitrogen load that flows into the river.
This change affects more significantly when the loss wetlands is used for agriculture that produces more nitrogen to the river.

21. Land Use
In the Lower Mississippi one third of the valley's forests were converted to agriculture between 1950 and 1976
In the Upper Mississippi where the largest inputs of fertilizer are, is where large amounts of soybeans and corn are grown
Corn is a fertilizer intensive crop

22. Policy Policy must address the source of the problem
The source is occurring all over the Mississippi Basin
Most of fertilizer comes from the area of Iowa, Illinois and Indiana
Decreasing fertilizer use in this area would the largest effect

23. Policy Policy must also take land use into account
Land use practices which mitigate eutrophication or reduce the fertilizer load should be encouraged
Organic farming which uses less synthetic nitrogen should also be encouraged

24. Consequences There are serious economic and environmental impacts
These impacts are felt in the Gulf but are started in the Midwest and Great Plains areas
Changes must be made in agriculture practices
People must realize that their activities have consequences a thousand miles away

25. Dead Zone: Environmental Impacts
Low oxygen levels
toxic algae blooms that can suffocate fish
change in food chains (an increase in phytoplankton, the lowest species on the aquatic chain)
altered ecosystems off shore

26. Dead Zone: Economic Impacts
Unreliable amount of fish in dead zone so fishermen must travel further for catch
This travel increases the cost of seafood
Quality is also significantly reduced

27. Dead Zone: Economic Impacts
The seafood business is an estimated $4 billion a year industry, a large and substantial part of our economy
The Gulf of Mexico is responsible for 40% of the countries commercial fishing yield; if wiped out entirely the effects could be detrimental nationwide.

28. Shrimp
When the shrimp leave the hypoxic zone the fisherman must travel farther to catch them
The shrimp are much smaller in size because of the low oxygen levels
There is less of a market for small shrimp then there is for larger shrimp

29. Possible Solutions Minimize the nitrogen usage
Use alternative nutrients and less nitrogen fertilizer
Better manure-nitrogen management
Apply nitrogen at optimum time and correct rate
Alternative cropping system

30. Wetlands and Riparian Zone
Serve as buffers between agricultural lands and streams and rivers
Riparian zone increases the wildlife value

31. Tertiary Treatment System
By using environmental technologies and ecotechnologies, nitrogen can be controlled.
It is easy as control can be done from the point source.

32. Some Programs to Mitigate the Problem
Industry Lead Solutions (ILS)
EPA Targeted Watershed Program
USDA-NRCS Conservation Effects Assessment Project (CEAP)
Iowa Soybean Association
Costal Restoration Strategies
Nutrient best Management Practices Endorsement

33. Other Examples Lake Erie dead zone Baltic Sea dead zone
Caused by phosphorous
Baltic Sea dead zone
Nitrogen use in inland Europe

34. Any Questions?