There are areas in our global ocean devoid of life. Forty years ago there were fewer than fifty of these so-called dead zones. Today there are 405. The cause is directly related to agriculture, specifically our use of fertilizers. Dead zones can occur naturally in enclosed bodies of water or as a result of coastal upwellings and reduced winds and currents. However, it is our reliance on chemical nutrients, like nitrogen and phosphorous, that has brought about the devastation we see today.
Single-celled, plant-like organisms, called phytoplankton, live in the water column and feed on the nutrients found there. Excess nitrogen and phosphorous encourages a massive reproduction of these organisms, resulting in algal blooms. These blooms can reach immense proportions, gobbling up available oxygen as they spread. When they die, they sink to the bottom, and the dead bacterial cells decompose, depleting the O2 levels even further. Fish flee for their lives but slow moving, bottom-dwelling species often die. Fishermen have reported baby octopuses climbing up crab-trap ropes in order to get air.
The proliferation of these zones can be stopped. Call a halt to large scale farming. Demand reductions in the use of fertilizers. Pledge to make the ocean a living zone, not a dead zone!
What can you do?
A dead zone in 2006, off Newport, OR lasted 4 months, covered 1200sq.km and 80% of the water column.
By washing your car on grass or at a car wash you can help prevent ocean dead zones.