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RE: Dennerle philosophy

> > Subject: Re: conservation of energy
> > Jean Olson (JOlson8590 at AOL_com) wrote:

> > All this means to us is, all of the electricity consumed by our lights ends
> > up as heat, somewhere in the room. High efficiency lights put more energy
> > into the visible light spectrum. BUT, if there are no windows in the room,
> > what happens to that visible light? Where does it go? Oversimplified, it
> > bounces about the room changing wavelengths, part of it being absorbed at any
> > particular wavelength, and all eventually appears as HEAT.

> John Pitney (pitney at uiuc_edu) replied:
> What we are really trying to do is deliver light (energy) to the plants 
> to drive chemical reactions.  That energy, I would expect, doesn't reappear
> as heat until the plant tissue decays or gets burned or something.  The
> goal of the aquarium lighting folks is to get the most energy delivered
> to these chemical reactions per unit energy taken from the wall outlet.  
> Having an optimized spectrum helps a lot.  

Right!  Absolutely!  I try to avoid making "me too" posts, but I had 
to jump in here to agree with John.  As you are all aware, structural, 
chemical, and metabolic decay generate significant amounts of 
heat.  Thus, we have chemically stored energy that can actually 
be released for heat later.

We could go the next step:  Remember E = mc^2?  We are able
to convert much energy into a little bit of mass.  While this doesn't
happen at the temperatures in our aquariums <g>, you can have
light input without a heat output in a very efficient reaction.  The heat
is a by-product of a typically inefficient reaction (I believe plants are
approximately 2% efficient at converting sunlight to chemically
stored carbon-based compounds).  Also in agreement with John, 
shifting the spectrum can decrease the efficiency of this reaction
because ADP/ATP are most sensitive to photons of certain
wavelengths/energy levels.  

That's a good thing, too!  The inefficient reaction gives us the other 
98% of light to admire our tanks and light up the room!  ;-)

Further, biologically speaking, deviation from a working system tends
to decrease individual efficiency/stability/environmental fitness.  That's 
why mutations are generally a liability as opposed to a benefit.  Since 
sunlight has been around a long time, deviation from the sunlight 
spectrum usually results in a less efficient carbon-fixing reaction by 
plants.  While some plants do optimize one end of the sunlight spectrum 
or the other depending on ecological placement and resulting microclimate, 
the range of aquarium plants as a whole are typically more biologically 
fit in a tank whose light spectrum closely resembles sunlight.

--charleyb at cytomation_com

> Subject: Re: Dennerle philosophy.

> > Quoting the Dennerle philosophy...
> >    " ... alga love an oxidising environment, they develop particularly
> >well and produce more and more oxygen, far too much for the fish to
> >consume in such large quatities.

> From: "Roger S. Miller" <rgrmill at rt66_com>
> The first sentence is the key assertion in this whole story, and unless
> something important is left out then it is an unsupported assertion.  I
> can accept that algae (or plants) can and often do produce much more
> oxygen than the respiring critters will consume, but I see no evidence
> that this favors algae.

Darn it, I'm doing it again.  "Me too."  I would like to see some rational
explanation for algae environmentally favored over vascular plants in a 
high-oxygen environment.  None of my tanks seem to agree.  I suppose
one could argue that suspended algae (green water) might, because of
greater algae distribution, out-compete higher plants for the more limiting 
CO2 or other water column nutrients; however, that doesn't help for 
non-suspended algae cells.  In contrast, I would argue that the extra O2 
in the water would oxidize those little one-celled guys out just as much, 
where the vascular plants have a "buffer" of a relatively difficult-to-oxidize 
epidermal layer. 

> >    Excessive amounts of oxygen will quickly destroy natural chelates:
> >the water will become more "aggressive".  The excessively high oxygen
> >content destroys the essential vitamins and renders the trace elements
> >inactive.  Plants, as well as fish, will then suffer from trace element
> >and vitamin deficiencies.

I *loved* Paul's post on this so-called oxidation problem:

> From: Paul Sears <psears at nrn1_NRCan.gc.ca>
> Subject: Re: Oxidation of trace elements
> 	I have noticed many times in the APD concerns about oxidation
> of trace elements for plants, and a few recent posts have brought the
> subject up again.  For almost all of the things plants need, oxidation
> cannot be a problem.  I'll go through the list:  <snip, great list>

In view of this, oxidation doesn't seem to matter much for most
trace elements.  Further, that shouldn't give algae an advantage
over rooted plants, but the other way around as Roger pointed out.

I don't want to pick any fights, but if this is an adequate representation
of the Dennerle method, then I'm not very impressed.  Perhaps it
is merely "old science" that we can look back upon with a sad
shaking of the head.