Date: Thu, 22 Jan 98 6:24:08 EST
From: boddhisatva <kbevans-AT-panix.com>
Subject: Re: M-I: Fertilizer runoff kills marine life







		To whom...,



	It is important for people who are interested in ecology to avoid
lumping together types of pollution.  When phosphates and nitrogen are
added to the aquatic environment they cause eutrophication and plants,
microbes and plankton bloom.  Most ecology students are presented with
vivid examples of the way in which reducing phosphates from detergents
made green, soupy, yucky, hypoxic streams clear again.  Because nitrogen
and especially phosphorus are limiting nutrients in most aquatic systems
(meaning that the system can support more life, but for the lack of these
nutrients) they cause a dramatic change when they are loaded into the
system from fertilizer, manure (including human), detergents, runoff from
phosphate mines, etc. Although nutrient loading is devastating in the
short run, even causing blooms of toxin-producing algae and forcing the
system into hypoxia (where oxygen becomes a limiting nutrient), it is
ultimately too much of a good thing.  In time, nature deals with nutrient
loading by producing bogs, marshes, mudflats, wetlands and other
ecosystems that contain large amounts of anaerobic life forms.  Nature
rarely has to deal with such intense loading, however, so near-term
destruction to coral reefs and stands of aquatic vegetation can be
considerable and unacceptable. 



	The important thing is that the best treatment for eutrophying
pollution is bio-remediation.  That requires that potential nutrient
pollutants are not mixed with things such as toxic organic compounds and
metals.  Sewage schemes and dumping can stop obvious eutrophication, but
they can mix nutrients with chlorine and other wastes.  They can also fill
up landfills.  When farmers have to deal with anti-eutrophication
measures, they may create dangerous waste dumps and pools on their own
land which often become contaminated with herbicides and pesticides, trap
and kill waterfowl, and threaten drinking water.  As for agricultural
policy, if farmers abandon acreage because of the absolute and competitive
costs of fertilizer-reduction, that acreage will likely be given over to
sprawl development with its attendant pollution.  Farmers may be tough on
the land, but they don't pave it or build trailer parks, industrial parks,
golf courses, strip malls or office buildings on it.  Keeping maximum
acreage under till is usually wise. 




	Nutrient wastes can safely be allowed to run into natural systems
as long as they are free from toxins and channeled to the kinds of
ecosystems that can handle them.  When it comes to nutrient pollutants,
*separation* for natural recycling is more important than absolute
reductions.  That goes for municipal waste as well.  The problem is that
people get so upset by the yucky algae that they demand quick fixes
instead of responsible waste policy.  Those algae are symptoms of our
thoughtlessness, not pollution in and of themselves.  Nutrient pollution
is obvious and easily measurable (water clarity, oxygen content, plankton
profile, weed choking, fecal coliform counts) but it should not be a proxy
for the kind of pollution that remains toxic for decades and centuries.
Fertilizer and PCB's (for example) are totally different issues.  One you
can put on your compost heap, with the other you have to move away and not
come back without a gas mask. 






	peace




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