The causes of marine dead zones (eutropic or hypoxic) are fairly well understood. Nutrient dense waters are washed into the ocean and cause phytoplankton, which feed on the nitrogen and other compounds, to swell in population. This swelling of population uses up oxygen in the water.
Aren't the algal blooms a part of nature?
To a degree this is a natural phenomenon. There have been reports of red tides and massive algal blooms dating back centuries. Although it's a natural occurrence, the scale has become a serious problem. When large quantities of nitrogen rich compounds from man-made fertilizers, pesticides, herbicides and other sources are flushed into a body of water, the blooms take on a monstrous quality.
In the process of feeding on the nutrients the plankton consume oxygen in the water. When enough oxygen is consumed they begin to die. As their bodies settle to the bottom and decomposition begins, this process consumes more oxygen. In short order the level of oxygen dissolved in the water becomes nearly zero. Anything in that patch of water not able to swim or crawl away dies. This includes coral, sea plants, slow moving crustaceans and shellfish.
You don't have to worry about this problem if you aren't a fisherman, right?
Consider this – fish and products made from fish account for 20% of the animal protein eaten by humans. In Asia very close to 1 billion people rely on fish as their primary source of protein. Worldwide, fishing employs an estimated 200 million people. In the United States alone, NOAA reports that the commercial fishing intake for 2008-2009 was $8.3 billion dollars.
Overall, commercial fishing accounts for approximately $60 to $70 billion in income for countries around the world. That's taxable income that can be used locally to build roads, schools, and other public services.
The marine dead zones primarily impact coastal waters. As of 2008 there are 169 known hypoxic areas in the world and every one of them is within 20 miles of coast line. Hypoxic is defined medically as a deficiency in the amount of oxygen delivered to body tissues.
The immense size of the zones has a negative impact on commercial fishing. When oxygen levels drop, the fish move on. It becomes necessary for the fishermen to go further out requiring more fuel and effort. The added cost is passed on to consumers in the form of higher prices and less availability of popular fish.
Animals like scallops, shrimp, crab, lobsters or other slow moving crustaceans are killed outright. Remember, scarcity drives up prices; its a standard practice.
Do the dead zones lead to a loss of jobs?
When the price to catch fish becomes too high, companies and individuals stop fishing. It's a fact of life that if an industry cannot support itself it withers.
In 1992 the Newfoundland cod fishery collapsed. As a result 40,000 people lost their livelihoods. The reasons were more related to overfishing than dead zones, but think about it, no fish is no fish, no matter the reason. This isn't an isolated incident. So the question again - does a loss of fish cost jobs?
Although it seems like a far away or minor problem, there is plenty of evidence to show that anything that affects the ocean, eventually affects us all.
References:
World Fisheries: Declines, Potential and Human Reliance, University of Michigan, Jan 2006. Web. Accessed Feb 2, 2011
Ellis, Richard . Encyclopedia of the Sea. New York: Knopf, 2000
Coleman, Barbara A., Doetsch, R.N., and Sjoblad, R.D. "Red tide: A recurrent marine phenomenon."Sea Frontiers 32(3):184-192, May-June 1986.
Ronn Hanley - I've been writing on and off since I was 12. Most of it was throw away fantasy and horror and the strange imaginings of my primordial ...
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