By Jim Minick, Bay Journal News Service
Summertime for sweet tea, serenades, and, of course, dead zones.
Just float the outlet of any of our major rivers and youll encounter algae blooming in such vast spaces as to swallow the mind. Chesapeake Bays dead zone amounts to roughly 40 percent of its total area. Mississippi Rivers dead zone, our countrys largest, covers 8,500 square miles, or about the size of the state of New Jersey, according to scientists Robert Diaz and Rutger Rosenberg. All that algae makes us witnesses to an era that researcher Jeremy Jackson calls, the rise of slime.
The primary cause of these slimy sectors of death is nitrogen (N). We pour it onto our fields as fertilizer, blow it out our tailpipes and smokestacks as exhaust, or flush it down our toilets as waste, and we do this in such excess that we overwhelm the nitrogen cycle.
Rains flush nitrogen off fields and streets and into our rivers where bacteria normally denitrify the water, returning the excess to the atmosphere as gas. An average stream, however, can only eliminate about 16 percent of the excess nitrogen. Were pouring on so much N that much of it gets to our coastal waters, including the Chesapeake Bay.
When the rivers empty into bays, this excess N fertilizes the algae, causing the blue water to turn slimy green with huge blooms. Then the algae grow and die fast, day after day. The dead algae are consumed by a different kind of bacteria which uses up the waters oxygen, creating dead zones; no oxygen traveling through the gills of fish, crabs, and clams means those creatures cant survive in the dead water, and those that cant move, suffocate.
According to Diaz and Rosenbergs research, only four dead zones existed in 1910. In 2008, these scientists examined all of the worlds coastal waters and counted 405 dead zones, covering an area of 95,000 square miles. Thats ten times the size of the Mississippis dead zone, or the size of New Zealand.
Like plants and animals everywhere, we each need nitrogen. It fuels our bodies and is an essential part of our DNA. We just dont need so much. In our air, too much nitrogen oxide cause acid rain and another atmospheric form, nitrous oxide, contributes to climate change. Too much nitrate in our drinking water hampers our bloods oxygen levels and causes blue-baby syndrome. And a new study published in the Journal of Alzheimers Disease reveals that too much N in our bodies is linked to diabetes, Alzheimers, and Parkinsons diseases.
Suzanne de la Monte, the lead researcher of this study, examined our societys recent and dramatic increase in using nitrate-based fertilizers. She found the application of these amendments doubled between 1960 and 1980, and this just precedes our current epidemic of diabetes, Alzheimers, and Parkinsons diseases. Not only have we increased our intake of N indirectly through our farming practices, but we also regularly eat and drink sodium nitrate used as a preservative. Just read the labels found on bacon, burgers, or even wine.
We have become a nitrosamine generation, de la Monte claims. Once nitrosamines enter our bodies, they alter genes and damage DNA. She and her colleagues argue that the cellular alterations that occur as a result of nitrosamine exposure are fundamentally similar to those that occur with
Alzheimers, Parkinsons and Type 2 diabetes. The dramatic rise in these diseases, the investigators also explain, cannot be attributed to gene mutations, but instead reflect typical patterns of exposure-related disease. They conclude that chronic exposure to low levels of nitrites and nitrosamines through processed foods, water and fertilizers is responsible for the current epidemics of these diseases.
But heres another N problem. Nitrogen fertilizer, a major contributor to dead zones, presently accounts for feeding 40 percent of our global population. If we didnt have this form of fertilizer, almost half of us would not exist.
We can reverse these problems associated with excess nitrogen, if we choose.
The collapse of the former Soviet Union offers a modest example. When this government dissolved, many of the states huge farms closed. Many of its citizens by necessity returned to gardening. Likewise, the countrys farmers could no longer afford expensive nitrogen fertilizers, so they turned to traditional sources like manure. One result: the people had less food, but it was better for them. Another result: between 1991 and 2001, much of the Black Sea dead zone slowly disappeared.
It was once the largest in the world.
Jim Minick teaches English at Radford University in Virginia and is author of Finding a Clear Path, a book of essays.