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06.12 Too Much of a Good Thing

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lauren briley

on 10 March 2014

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Transcript of 06.12 Too Much of a Good Thing

Types of Nutrients in the Dead zones
Solutions?
An obvious solution is to stop the use of synthetic fertilizers because they are the clear source of nitrogen and phosphorous, which are the leading cause of hypoxia.

However, this is
unlikely
because many industrial farmers rely heavily upon these fertilizers, and most of the food grown in industrialized countries comes from industrial farms. So, it is more logical to consider lowering the use of fertilizer, and only using as much as the soil can absorb.

Using natural sources of nutrients, such as compost and manure, and farming methods such as no-till and contour cropping would be effective at reducing runoff because they allow soil to absorb more water and nutrients.

The Ladder
Event 4: Description/Details:
And as you have it, a Dead Zone has become.

Event 3: Description/Details:
Starved of Oxygen, the deeper water becomes a "Dead Zone".
Fish either avoid the area, or die. Tiny organisms that form the vital base of the Gulf food chain, also die.

Event 2: Description/Details:
When the Algea die, they sink into the "saltier" water. Decompse, using up the Oxygen in the deeper water.

Event 1: Description/Details:
Nitrogen and Phosphorus from the fertilizer in the freshwater layer ignite algae blooms.


06.12 Too Much of a Good Thing
Lauren Briley

What is a "Dead Zone"
Dead zones are low-oxygen areas in the world's oceans and large lakes, caused by "excessive nutrient pollution from human activities coupled with other factors that deplete the oxygen required to support most marine life in bottom and near-bottom water.
Causes of Eutrophication
Another solution would be to restore coastal wetlands, which would provide a natural filter and help to remove the excess nutrients from the water before it reached the ocean.

The wetlands could help to serve as a sink for the nutrients .
Regardless of how it is done, this problem must be confronted.

As developing countries become more industrialized, it is likely that they too will begin overusing fertilizer, creating more dead zones in ecosystems that are currently healthy.
Florida Keys
Dead Zone
In countries like the United States, heavy use of animal manure and commercial fertilizers in agriculture are the main contributors to eutrophication. Runoff from large agricultural fields enters creeks and bays because of rain or irrigation.

Factories and sewage facilities are less regulated than they are in developed countries, and sometimes wastewater is simply dumped into creeks, rivers, lakes, or the ocean.

Sources of nitrogen also contribute to eutrophication in some areas of the world. Fossil fuels and fertilizers release nitrogen into the atmosphere. This atmospheric nitrogen is then re-deposited on land and water through the water cycle rain and snow.
Dead zones occur because of a process called eutrophication, which happens when a body of water gets too much nutrients, such as phosphorus and nitrogen. At normal levels, these nutrients feed the growth of an organism called cyanobacteria, (blue-green algae).

With too much nutrients, cyanobacteria grows out of control, which can be harmful. Human activities are the main cause of these excess nutrients being washed into the ocean. Because of this, dead zones are often located near inhabited coastlines.
Sewage
Can be point or non-point pollution. Adds phosphates and nitrates to water, can create explosive algal blooms which reduce the oxygen supply.

Urban Runoff
Nitrogen, phosphorous and various toxins from gardening fertilisers, pesticides and herbicides, urine and feces from pets, leaf litter, cleaning agents used for cars and other surfaces, petroleum products from cars.

Agriculture
Non-point source pollution. On-point and unregulated runoff of pesticides, herbicides and fertilizer nutrients, also and fecal coliform bacteria which causes illness in humans.

Landfills
Many sites filling with solid wastes probably originally occurred below the water table in their early stages. Probably little or no control over materials deposited in the early years. There is a significant potential for contamination of groundwater and surface water from these inactive landfills.

Industrial Waste
Heavy metals, such as mercury, tin and lead, there are also high tech chemical compounds (synthetic organics). These not only kill some species outright but also contaminate survivors and the food chain. Survivors affected with diseases, deformities, and lesions, weakens the immune system and can impair ability to resist natural enemies.

Atmospheric Pollution
2.4 billion pounds of chemicals per annual from U.S. Industries, of which large quantities end up in the marine environment.

Dumping at Sea
Marine debris dont just come from dumping at sea but are also often washed out by rivers.
Half of all marine debris today are plastics. These are highly visible and long lasting.


SOURCES
http://www.smm.org/deadzone/causes/dead-zone.html
http://www.seattlepi.com/national/article/Massive-dead-zone-fouls-gulf-off-Florida-1083287.php
http://www.washingtonpost.com/wp-dyn/content/article/2008/08/14/AR2008081401910.html
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