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Old 02-10-2018, 08:01 AM   #11 (permalink)
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Default Re: The biology of the color "red"

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Originally Posted by Phil Edwards View Post
I visited Neil Frank a couple months ago and his plants are BRIGHT red as are Diana Walstad's, particularly their Rotala macrandra. What intrigues me is their general low Nitrate levels. Neil doesn't dose much but does have significant amounts of peat in his substrates and Diana don't dose at all, though the decomposition in her tanks puts off what her plants need. Both people can grow some very healthy plants under these conditions and they happen to be bright...

That got me thinking that perhaps in some tanks it's a symptom Nitrogen deficiency. Because the plants don't have as much food they don't produce as much Chlorophyll. Since Chlorophyll masks the other pigments the red coloration should come out more.

Although I haven't tested it yet, I feel red coloration also depends on the color spectrum of the light it recieves. Since the Carotenoid pigments are best at absorbing blue light, bulbs with a higher amount of blue output should encourage red pigmentation in the plants. I've received quite a bit of anecdotal evidence to corroborate this, but haven't done it yet myself.

Finally, light intensity. Most of us have had plants get redder the higher in the tank they are and/or as more light is shed into the tank. Some folks think this is a "sunblock" reaction. Without knowing the biochemistry behind it I'd have to disagree. If plants underwater need to protect themselves from the sun why aren't all land plants red? Wouldn't they want a blue pigment to reflect the harmful high blue/UV spectra? Furthermore, why are so many species of photosynthetic algae that live at depth red?

Here's some interesting information:
The Solar Constant, the amount of incoming solar radiation (insolation), that reaches the upper atmosphere is equal to 1370 watts/square meter. The SC for the earth's surface is between 800 and 1000 watts/square meter, depending on altitude and atmospheric conditions. That's an average of 800 watts/32 square feet at sea level under average open sky! Take into account the effects of humidity, clouds, and possible cover from other foliage and you're talking less than that.

Consider the average high light aquarium with 3.0w/g (165watts) over an area of 4 square feet (55g). Nature=100watts per 4 square feet, Aquarium=165 watts per 4 square feet, that's an increase of 65% over nature!!!

Are those plants are growing so fast under that much light that they can't produce that much chlorophyll? I think the more likely reason is that there's so much light getting to them relative to their needs that they don't need to expend all that energy creating excesses of pigments they don't need much of.

Insolation and solar angle would also explain why FAN's plants are redder than Tropica's. The greater solar angle in Denmark decreases the amount of light available to the plants vs. the pretty direct light in Florida.

Best,
Phil
i just got done reading this thread and phils post(s) stood out to me the most.
I dose EI with the NilocG mixable dry fertz, so... i dose 10ml of micros And macros every other day (dif days for each, dont dose sunday) in my 40b... Should i increase dosing? or even triple this?
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Old 02-10-2018, 09:45 AM   #12 (permalink)
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Default Re: The biology of the color "red"

I think there are some bad assumptions in that post. For example, you cannot equate watts per gallon or watts of lighting to the solar constant, which is expressed in watts of sunlight. A watt of electricity powering a light bulb is far from being a watt of light. Since light bulb efficiency is expressed as lumens per watt, not watts of light per watt of electricity used, and lumens is not a measure of total light, but light as seen by humans, I don't know how many watts of electricity are needed to produce a watt of light. Even if I did, the light from a fluorescent bulb is so much different in spectrum than the light from the sun, I don't think there is a way to calculate the efficiency of a light bulb. But, lets just assume a typical bulb converts 10% of the electricity it uses to light energy. If that is close to being the case, the 165 watts per 4 square feet mentioned is really about 16 watts per 4 square feet, which is about 16% of sunlight, something I believe we all know anyway. (PAR from direct sunlight is roughly 2000, while typical aquarium lighting is 100)
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Old 02-10-2018, 09:48 AM   #13 (permalink)
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Default Re: The biology of the color "red"

wait so Should i increase dosing?
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Old 02-10-2018, 05:59 PM   #14 (permalink)
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Default Re: The biology of the color "red"

If you follow the EI tables you shouldn't be off too much on dosages. The tables assume high light, so you shouldn't need to dose more, except for very unusual situations. With less than high light you could reduce the dosages.
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Old 02-22-2020, 12:02 AM   #15 (permalink)
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Default Re: The biology of the color "red"

Quote:
Originally Posted by Phil Edwards View Post
The Solar Constant, the amount of incoming solar radiation (insolation), that reaches the upper atmosphere is equal to 1370 watts/square meter. The SC for the earth's surface is between 800 and 1000 watts/square meter, depending on altitude and atmospheric conditions. That's an average of 800 watts/32 square feet at sea level under average open sky.
Hi Phil Edwards

Sorry, I'm new around here so it seems a bit impertinent to be picky. Therefore, please accept this is an observation, not a criticism: 1 square metre = 10.76 square feet.

Yorkie
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Old 02-22-2020, 03:48 PM   #16 (permalink)
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Default Re: The biology of the color "red"

Good point, and you were the first to notice (or at least comment) in 2 years! Another consideration is that 80 watts of light energy (solar radiation) is more light than what you'd get from an 80 watt (electrical use) light fixture, even for a pretty efficient one.
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