Hi,

I was looking up some info about lighting in aquaria, the grow of
plants and the formation of algae.

In this search I came across an interresting, and for me new, fact.

In short it says :
"Algae use the blue side of the spectrum while plants can also grow
healthy on the red side only"

So excluding the blue side can / should reduce the growth of algae !!

This was stunning to me because special lamps for plants have both
blue AND red spectra in them.

I use the following picture for further explanation :
http://users.pandora.be/worldofbudgerigars/!spectrum1.jpg

legend :
A) TL - warm white (normal TL)

E) TL - GroLux (special lamp for plants)

I) daylight (sun)

J) spectrum used by plants for fotosynthese

What do we see ?

J is the spectrum which plants should need, so they made the lamp E
(almost identical spectrum)

But now I read that algae use mostly / only the blue side while plants
don't really need the blue side and can live with the red side alone.

So this means that a normal TL (A) should be a far better choice.

Now I can understand why sunlight (J) is so bad to our aquarium in
regard to algae growth (see how much blue there is in sunlight !)

now MY QUESTION :
Is there any scientific source (link / book) which deals with the
fact the algae use basically blue and plants need only red ?

I don't believe everything I read ;-)

TIA

PérRµ§h

--

A: Because it messes up the order in which people normally read text.
Q: Why is top-posting such a bad thing?
A: Top-posting.
Q: What is the most annoying thing on usenet?

some of the lights in stores say "promotes invertebrate growth" if we have
crabs/crayfish/shrimp do we need a special spectrum? would denying as much
blue light as possible to the tank hurt them? Also, exactly how does the
mostly red light look, if it gives a weird "satan tank" look to the thing
then I'd rather have algae :-P

(sorry for top posting but I find it easier to read since i don't have to
scroll through 5 pages of text I've already read to get to the new stuff)
"LeighMo" wrote in message
...
Is there any scientific source (link / book) which deals with the
fact the algae use basically blue and plants need only red ?

I don't believe everything I read ;-)

Very smart of you. :-)

I've also heard that "blue light causes algae" thing, and there may be
something to it. But a lot of people grow plants under blueish lights
(like
those 50% actinic SmartLites) just fine. I'm skeptical about the idea
that you
can control algae just by light spectrum.

But if there is any solid info, I'd be interested in seeing it, too.



Leigh

http://www.fortunecity.com/lavender/halloween/881/

On Thu, 20 Feb 2003 04:12:52 GMT, in rec.aquaria.freshwater.plants
"Christopher" verruimde onze geest met:

Also, exactly how does the
mostly red light look, if it gives a weird "satan tank" look to the thing
then I'd rather have algae :-P

**
mostly you don't see any difference at all.


(sorry for top posting but I find it easier to read since i don't have to
scroll through 5 pages of text I've already read to get to the new stuff)

**
If you cut away the lines which aren't usefull anymore and only leave
those whom you're replying to, you don't get 5 pages ...

PérRµ§h

--

A: Because it messes up the order in which people normally read text.
Q: Why is top-posting such a bad thing?
A: Top-posting.
Q: What is the most annoying thing on usenet?

On 20 Feb 2003 03:35:35 GMT, in rec.aquaria.freshwater.plants
tose (LeighMo) verruimde onze geest met:


I don't believe everything I read ;-)

**
It's not only from reading. An experienced breeder told met that
those "plant-lights" were crap, that they only stimulated algae
growth.

Then I went to the www and found the red - blue story on several
sites.


I'm skeptical about the idea that you
can control algae just by light spectrum.

**
I haven't said that you can control them ONLY by light choise, but the
light can give algae a better or a worse enviroment.

Ofcours NO3 and PO4 will influence the growth too.

ps : still looking for evidence

PérRµ§h

--

A: Because it messes up the order in which people normally read text.
Q: Why is top-posting such a bad thing?
A: Top-posting.
Q: What is the most annoying thing on usenet?

On 20 Feb 2003 11:36:28 GMT, in rec.aquaria.freshwater.plants
tose (LeighMo) verruimde onze geest met:


But those sites often take info from each other. It's really easy to spread
false info on the net, I'm afraid.

** true ;-(

** Although many site told that special plant lamps (like GroLux)
don't work.

I've never seen any actual research on this, just anecdotal claims. Which I'm
not discounting, mind, but some solid proof would be nice.

** If I find nothing, I'll do my own test :-)

**
I found one interresting hypothesis why algae prefer blue and plants
can do with red.

You know that blue light travels easier through water than red light.

This theory stated that algae develloped mainly in the sea where much
more blue light was available than red one. When (water)plants
develloped they went out of the water and were able to receive the red
part anytime they wanted, so they became more sensitive to it.

Sound logical, but that's not enough

PérRµ§h

--

A: Because it messes up the order in which people normally read text.
Q: Why is top-posting such a bad thing?
A: Top-posting.
Q: What is the most annoying thing on usenet?

Ron Kundla wrote in message . ..
http://www.madsci.org/posts/archives...6481.Bc.r.html
This one is interesting because it says that photosystems in plants
can ONLY use red light. The photosynthetic pigments absorb light at
different wavelengths and 'down-convert' it to red light. This
includes things from trees all the way down to blue-green algae!

That's the deal Neil.

The down conversion means that only shorter wavelengths than 680 and
700 nm will be used. These are higher energy.

All those other pigments absorb higher energy wavelengths
(smaller/shorter wavelenghts).

Plants and algae can change these pigments to maximize their capture
of light.

Regards,
Tom Barr

What *do* you do for a living Tom? You have to be one of the most
knowledgable plant people who roams the Internet. Are you a biologist
or botanist?

A botanist or biologist? How about both.
I'm a grad student.
Regards,
Tom Barr

So the presence of these other pigments allows a plant to utilitze a
wider range of visible light wavelengths to power photosynthesis?

Would this imply that a plant would be more efficient in its
photosynthesis in the red range versus any of the others? The
photosynthesis action spectrum seems to show that certain blue
wavelenghts provide higher photosynthesis rates than red wavelengths.

Am I completely messed up here?

On 21 Feb 2003 14:14:18 -0800,
) wrote:


That's the deal Neil.

The down conversion means that only shorter wavelengths than 680 and
700 nm will be used. These are higher energy.

All those other pigments absorb higher energy wavelengths
(smaller/shorter wavelenghts).

Plants and algae can change these pigments to maximize their capture
of light.

Regards,
Tom Barr

http://www.madsci.org/posts/archives...6481.Bc.r.html

This one is interesting because it says that photosystems in plants
can ONLY use red light. The photosynthetic pigments absorb light at
different wavelengths and 'down-convert' it to red light. This
includes things from trees all the way down to blue-green algae!

It is by no means inconcievable that different organisms are sensitive
to different areas of the spectrum.

be aware though that unless your light looks red or orange, there is
blue in it!

Algae and aquatic plants can use both blue and red wavelengths and
everything in between.
Algae and plants both live and grow in water less than 3 feet, the
issue of blue wavelengths are not that great when dealing with the
average tank.

Turbidity will remove all wavelenghts not just blue and this is common
in a number of natural systems. Tannins will selectively remove
certain wavelenghts.

Both algae and plant both possess Chl a as their final energy transfer
molecule before splitting the water for e-'s and H+'s. There are two
special Chl a's called *P680 and *P700.
Chl b, c, d, and all the other pigments like beta carotene etc only
use wavelenghts that are higher energy (shorter wavelengths). These
lose energy and relax down to the lower energy levels and are funnels
into these final transfer molecules. Lower than 700 nm are not usable
by plants or algae. You cannot go "uphill" so to speak.

All the enegy from these assessory pigments are transferred via
resonance to the reaction center Chl a molecules.
Some bacteria can use longer waveleghts and have only a single
reaction center molecule instead of a pair like Chl a.

But algae and plants can alter and change their ratios of these
pigments to catch whatever is being offered.
You can change the colors but you often will get the same algae or a
new
species to fill it's place.

Blue light responses in plants allows more CO2 since the stomata open
even larger when the plant is exposed to blue and better growth occurs
and it looks better to our eye if the color is well balance.

You get a more efficient watt to quantum yield of plant growth if you
stay close to the Chl a's spectrum but, the plant can handle most
things you throw at it. Same goes for the algae. They are _extremely_
similar biochemically.

You gain no advantage by using so call plant bulbs that "reduce
algae".
If they can show practical evidence in a plant tank this occurs, I'd
love to see it.
Otherwise it is pure speculation and I think , BS.

I've used all sorts of colors and have found nothing that would
indicate a better final steady state that give any advantage to the
plants vs the algae.

After about one month both algae and plants have adapted to whatever
color temps/wavelenght you have provided for them.

At the light level, algae and plants are too close to make any use of
this and algae can live on a order of magnitude of less light than
higher plants. Waste of money IMO/IME but what your eyes precieve how
the plants appear in certain light color is something to consider.

A 10000K 40w bulb will grow plants. But you get less useful light
since the higher wavelenght will need to lose some energy before it
makes it down to the reaction center. The excess energy can be given
off as fluorescence, heat etc. A warmer red colored bulb with a blue
spike will give the best preformence but the light will all funnel
down to the same place. But as far as useable light energy, the
660-700 range is great watt for watt. Looks ugly and the blue spike
will open stomata more and make things look better also.

5000-6700K looks good, Triton's 7500K look good and the 8800K bulbs
look good also. I use 4300K bulbs in MH's and also 6500K's.
Get temps in these ranges and your fine. Good color for your eye and
the plant's needs.

Regards,
Tom Barr

bowing down before Tom

We're not worthy! We're not worthy!

getting up off of the floor

What *do* you do for a living Tom? You have to be one of the most
knowledgable plant people who roams the Internet. Are you a biologist
or botanist?