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Re: Limnology Was "Re: NFC: Fw: Yes, please help me.
The o2 gradient and where the waer becomes hypoxic to anoxic is greatly
determined by the bioload of the lake. if there are very few nutrients
entereing the lake and low amounts on orgamismis in the lake there can be
o2 all the way to the bottom. if there is alot of nutreient influx and
high amount of nutrinets then the bottom of the lake is going to be
anoxic. By dividing the water bodies in to oligotrophic (low bioload) and
eutrophic ( high bioload). it allows us to easily get a idea of alot of
processes that occur in the water body. an easy way to tell the diffrence
between oligotrophic and eutrophic and the gradiation in between is
looking at water clairity and water color. ultra oligotrophic lakes are
crystal clear and very blue, and you can see many many many meters down(
>75m), think about crater lake. Oligotrphic lakes you can see fairly deep
they are still really clear abut may be a bit more green that the
ultraoligotrophic lakes. Mesotrophic lakes have a moderate clarity being
able to see approx 20 ft, blue green in color. Eutrophic lakes are
green but not split pea soup green with low water clarity. ultra
eutrophic lakes are those that are split pea soup green with water clarity
less that one meter.
There is a really good text out there on limnology. IT is Wetzel, R.G.
Limnology 2nd ed. 1983. The third edition should be out now Wetzel was
working on revising it two years ago.
On Sun, 25 Jul 1999, David A Zitnik wrote:
> I think it is different for every lake. Usually, however, it parallels
> the rapid change in temperature (thermocline), as this tends to form a
> diffusion barrier between oxygen rich water at the surface (epilimnion)
> and the oxygen poor water near the substrate (hypolimnion).
> On Sat, 24 Jul 1999, D. Martin Moore wrote:
> > Dazzle, at what depth does the water become anoxic?
> > > This brings up an interesting question. For my whole life, I assumed that
> > > deep water in lakes was a cool refuge for fish in the summer. However,
> > > last semester, when I took limnology, I was taught that the deep wter in
> > > lakes (below the thermocline where it is cool) has virtually no oxygen.
> > > Lab testing backed this up. So, according to this, a shallow lake would
> > > not be at a disadvantage to a deep lake in the summer. In fact, when
> > > lakes turn over in spring and fall, deep lakes often experience fish kills
> > > due to the mixing of the oxygen-poor deep water with the rest of the lake.
> > > Now, I am far from an expert on this, so I will gladly accept
> > > comments/questions/criticizms. What does everybody think?
> > FWIW, David
> > Prost,
> > Martin
> > -----------------------------------------------------------
> > Greater American Freshwater Fishes Resource Site (GAFFeRs): http://www.localink4.com/~archimedes/
> > "Fie on thee, fellow! Whence come these fishes?" - Scheherazade
> > "Any fish with good teeth is liable to use them." - Wm. T. Innes
It's smegging stupid. Two grown men on unicycles belting a beach ball up
and down the corridor...with french loaves.