"Derek Broughton" wrote in message
...
Reel McKoi wrote:
"George" wrote in message
news:J5M4e.15943$Vx1.13708@attbi_s01...
Starting with autumn, let's see how the pond changed into the winter.
The
water
at the surface started out in October at 42°F. The first frost and cold
wind
lowered the surface layer and it sank, while the warm water rose and
replaced it
and was chilled in turn. This circulation process continued until all
the
water
reached 39.2°F, at this temperature water is at its heaviest. Normally,
any
cooling beyond 39.2°F does not sink, instead forms a thin layer at the
surface
because of the local geothermal gradient, ...........
============================
This has not been our experience. When our ponds are forming ice at the
surface (coldest place), the bottom can be anywhere from 39 to 42
degrees.
Nothing but a small surface pump (or air stone) runs to keep a hole in
the
ice. There is no current to mix the water and disrupt natural
stratification or disturb the hibernating fish.
That's pretty much what George said :-) If water's densest at 39.2°F,
then
(at least in water deep enough to stay liquid and have a noticeable
temperature gradient) the water should never get colder than that but
could
be warmer.
--
derek
=====================
Whoops,.. I should have read it closer. Thanks for bringing that to my
attention. ;-)
--
McKoi.... the frugal ponder...
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