Date: Wed, 2 Apr 1997 22:52:24 +0200 From: Mark van Kleunen <M.vanKleunen@stud.biol.ruu.nl> To: cp@opus.hpl.hp.com Message-Id: <aabcdefg1242$foo@default> Subject: Re: water
At 09:24 2-04-97 -0800, you wrote:
>As I said, I am not a scientist and I would like you to elaborate a bit
>here. I love to learn. Have you seen any studies which show rates of
>nutrient increases? How fast is this actually happening?
>
>
>Take care & keep on growing,
>
>-Tom-
>
Hi Tom,
In my country, The Netherlands, the atmospheric nutrient deposition causes
real problems in many ecosystems. In the natural situation (which is for
example still found in Norway) the atmospheric nitrogen deposition is 5
kg/ha/year. In the Netherlands the average deposition is 50 kg/ha/year and
in some parts even 500 kg/ha/year (While farmers fertilize their fields
nowadays with ca. 200 kg N/ ha/year). This increase is caused by industry,
trafic and agriculture during the last 30 years. Most plants like a higher
nutrient gift, but some species benefit more than others. This causes that
some species overgrow the others. For example, in the Netherlands we had
many heaths (I don't know whether this is the correct english term for
fields mainly covered with Erica), this heath is now replaced with one or
two grass species which use the extra nutrient deposition more efficiently.
Restoration of the heath needs the costly removal of nutrients from the
ecosystem. This is achieved by removing the surface layer of the soil or by
grazing animals (sheeps and cows). This was in short what acid rain (i.e.
the liquid and dry atmospheric deposition) may cause besides the problem of
lowering the pH.
The amount of nutrients in rain water will thus differ between different
locations on earth. I don't think that the nutrients in your rain water will
have negative effects on cp in culture, since there are no other species
that can overgrow them.
I hope this may help you to clarify what I meant. There are many scientific
and non-scientific papers on this subject, however, I could only find some
written in Dutch.
Regards, Mark
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