Plant life under a red sun

[mikegarrison]

Ask yourself where photosynthesis came from. Most probably, it came from single-cell organisms which got energy from the sunlight being absorbed into the cells of multi-cell organisms (plants).

So if there is life at all, it might have something like cells. If it has something like cells, it might have multi-cellular organisms. If it has those, they might include something to extract energy from the sunlight. Go from there.

[fredinno]

30 minutes ago, luizopiloto said:

In such planet... there will be no vegetables... only fungus... Mushrooms everywhere... or just Ice...

Why?

[lajoswinkler]

4 hours ago, Spaceception said:

I can't view it.

http://lisakimmorley.com/2015/02/08/a-matter-of-perspective/

 

2 hours ago, Xorth Tanovar said:

Until you get closer and realize they're not plants at all.....anyone remember Larry Niven's "Bordered in Black?"

That's... That will give me nightmares. 

 

1 hour ago, luizopiloto said:

In such planet... there will be no vegetables... only fungus... Mushrooms everywhere... or just Ice...

 

Fungi are saprotrophic, meaning they consume decaying organic matter. It's very difficult to imagine such ecosystem. Maybe with two or more species of fungi, alternating in time, eating each other...

There's no reason why such planet wouldn't have photosynthetic organisms.

 

1 hour ago, Creature said:

 

I thought we assumed Earth-like plantlife and surroundings. Of course if the biochemistry is somehow exotic, then it's a whole different discussion. I'm sorry but most of what you're saying just doesn't make much sense. In photosynthesis plants capture light by chlorophylls, which is a generic term for an organic molecule that covers several variations of the same basic structure. It has two major absorption bands at blue and yellow-red areas (hence the color).

The absorption spectrum is defined by the molecular structure. There are tons of pigments that absorb at near-IR for example. It doesn't work at all like you described. The pigment doesn't have to be "more sensitive" in any way, it just needs a different absorption band. Obviously the energy of longer wavelength radiation is much smaller, hence it's not a good source of energy for photosynthesis and the associated biochemistry would be different. I think there was a mention somewhere in Wikipedia about some plants even using IR for photosynthesis, but I won't vouch for it's accuracy.

In any case, the light absorbing molecule is still just a regular carbon-based organic molecule and their photobleaching properties are a completely separate issue. For example you can't just "bash" an IR-dye with UV kill it like you suggest. First of all it doesn't catch the UV light very well, it just passes over it. This is also a nice property, because it can be used for spectrophotometry. Second thing is that even if it would absorb it (and be an UV pigment instead), it would probably withstand our UV levels just fine since organic pigments do that fairly well in general. Unless you propose that the covalent bonds are somehow weaker around red dwarfs?

The reason why UV is dangerous for living things is because DNA has absorption maximum at 260 nm, which means that as long as the exoplants have DNA, they are susceptible to UV induced cell damage. This has zero to do with photosynthesis. Like I said, it's possible that life developing around a red dwarf might be ultra sensitive to UV, but it's just as likely that it would have the same resistance to it as any domestic plant. But since it's already hard to say if a plant from Siberia would live when transferred to Mongolia, it's impossible to say these things about a fictional exoplant.

 

The whole point of the thread is discussing exotic metabolism evolved to thrive in said conditions.

I don't know where you heard about that, but complex dyes are very sensitive to UV even though they can't deal with it in the usual fashion. That's why UV has a bleaching effect. It wrecks the conjugated double bonds in dyes which are responsible for their absorption spectrum.

If an organism has evolved in such a way it collects as much as possible of the energy weak photons, then those systems will be more sensitive to photons of lower wavelength. They will have structures easily energized by high wavelength so that the efficiency of the whole process is high enough.

[fredinno]

Umm, what about K-type stars or High-M-type stars?

It seems it can be anything but blue: http://www.astrobio.net/topic/deep-space/alien-life/colors-of-alien-plants/

https://www.theguardian.com/science/2007/apr/11/spaceexploration.plants

http://www.solstation.com/life/a-plants.htm

[Spaceception]

If anyone can make a detailed picture/want's to make one, could someone make a planetary landscape that has dark purple/dark red plants, dark green water, tan desert, and a light tan sky, with dirty white clouds? As well as one from the perspective from orbit?

Thanks

[Mitchz95]

What would the plant life look like on a planet orbiting a blue star (class O or B)? I know those stars don't live long enough for life to evolve, but it's been bugging me for a while and I'd love to have some idea.

[Spaceception]

6 hours ago, Mitchz95 said:

What would the plant life look like on a planet orbiting a blue star (class O or B)? I know those stars don't live long enough for life to evolve, but it's been bugging me for a while and I'd love to have some idea.

Quote

Autumnal to bluish colors. Main sequence stars brighter than the Sun (spectral types F and A and the very short-lived B and O) emit more blue and ultraviolet light than the Sun. Given sufficient time for Earth-type photosynthetic life to evolve (e.g., hundreds of millions to billions of years), planets around such stars could develop an oxygen atmosphere with a layer of ozone that blocks more energetic but potentially harmful ultraviolet but transmits more blue light to the ground than on the Earth. In response, life could evolve a type of photosynthesis that strongly absorbs blue light, and probably green as well. In contrast, yellow, orange, and red wavelengths of light would likely be reflected by such plants, so the foliage would have the bright colors found during autumn in Earth's deciduous forests all year round. On the other hand, some plants may reflect some blue light due to its overabundance and potential to "burn" photosynthetic organisms (e.g., like sunburn from ultraviolet exposure on Earth).

From, http://www.solstation.com/life/a-plants.htm

[PB666]

8 hours ago, Spaceception said:

From, http://www.solstation.com/life/a-plants.htm

The green is the middle of the spectral peak for the sun, blue is of higher energy. A nixture of both red adsorbing and blue absorbing pigments allows plants to grow faster. If ultraviolet and blue are removed plants will adapt with more red absorbing pigments, and appear black in red light and blue in white light. The problem is that growth will be slower, because there is about a quarter the energy available, it would be akin to growing typical earth plants on mars. To achieve the same growth rate the planet would have to be twice twice as close to its star, raising the temperature because its still adsorbing all that IR. Its credible. But red stars are also more prone to flaring, and this is a particular problem for close planets. 

Light is not one thing from an atoms point of view their is nuclear-penetrating rays,  ionizing radiation, chemosynthetic radiation, wobble radiation, molecular and structural radiation of higher level assemblages. Once you are below the frequency of the chemosynthetic radiation range, there will be no photosynthesis. Sure there are chemicals that have  such a loose hold on their outershell electrons they can do chemistry, but you would have to have some sort of aromatic sink to dump  enough of these into that you could do a 2 for one, or  3 for one trade on a single electron high enough to build. 

[qeveren]

For anyone wondering what Earth plants would look like under a red dwarf's light, the spectrum is basically that of a conventional incandescent light bulb.  Atmospheric scattering would shift the lighting a little bit more red, but I daresay they'd still look green to our eyes.

As for native plants, their apparent colour would depend on whatever pigments they end up evolving.  Remember, evolution is lazy and likes to half-ass things, and developing an "absorb all the light!" chemical complex is probably more effort that it's willing to put into things.

[kerbiloid]

Plants are not necessary green. http://www.livescience.com/1398-early-earth-purple-study-suggests.html

[Spaceception]

On 4/29/2016 at 0:45 PM, Spaceception said:

If anyone can make a detailed picture/want's to make one, could someone make a planetary landscape that has dark purple/dark red plants, dark green water, tan desert, and a light tan sky, with dirty white clouds? As well as one from the perspective from orbit?

Thanks

Anyone?

[todofwar]

There are more factors that go into this then just the color of the light. Chlorophyll itself isn't actually the best in terms of capturing light, but it is the best at the charge separation necessary for life (I suggest anyone with some chemistry knowledge read into photosystem ii, one of the coolest proteins out there imo). So, while they might not be green I don't know if they would be black. Also, photosynthesis evolved because of all this intense light around us. Below a certain threshold of intensity things seem to stick to chemosynthesis. So it's not for certain plants would evolve at all. Now, if you seeded a world with cyanobacteria I wonder if they would develop some kind of natural doubling pigment to convert red light to blue light to allow them to run their photosynthetic machinery. 

[PB666]

36 minutes ago, todofwar said:

There are more factors that go into this then just the color of the light. Chlorophyll itself isn't actually the best in terms of capturing light, but it is the best at the charge separation necessary for life (I suggest anyone with some chemistry knowledge read into photosystem ii, one of the coolest proteins out there imo). So, while they might not be green I don't know if they would be black. Also, photosynthesis evolved because of all this intense light around us. Below a certain threshold of intensity things seem to stick to chemosynthesis. So it's not for certain plants would evolve at all. Now, if you seeded a world with cyanobacteria I wonder if they would develop some kind of natural doubling pigment to convert red light to blue light to allow them to run their photosynthetic machinery. 

They would not, the conversion loses to much energy, it would have to dump two electrons into a sytem, one transferred at low energy and a second transferred at high energy. But, it doesn't, there are red photophores, the problem is that when we start talking about cool red stars and  brown dwarves and infrared, you have two problems one is finding an electron dropping photophore, and second a system of transferring two low energy electrons and gaining one higher energy electron that can be used to make H:, NADH or NADPH. 

[todofwar]

14 minutes ago, PB666 said:

They would not, the conversion loses to much energy, it would have to dump two electrons into a sytem, one transferred at low energy and a second transferred at high energy. But, it doesn't, there are red photophores, the problem is that when we start talking about cool red stars and  brown dwarves and infrared, you have two problems one is finding an electron dropping photophore, and second a system of transferring two low energy electrons and gaining one higher energy electron that can be used to make H:, NADH or NADPH. 

Either way it remains inefficient, so either double the photon or somehow double the electron. Life finds a way, but I don't know if such a system would naturally evolve. I guess the advantage is you can occupy more parts of the planet then a chemosynthetic organism. 

[PB666]

5 hours ago, todofwar said:

Either way it remains inefficient, so either double the photon or somehow double the electron. Life finds a way, but I don't know if such a system would naturally evolve. I guess the advantage is you can occupy more parts of the planet then a chemosynthetic organism. 

See other thread, yes chemosynthetic might use a combination of short  ir or deep red along with chemosynthetic in highly select circumstances, might generate O2 that would not accumilate because of the overall reducing potential, but I think life is a foregone conclusions in many systems, including large rocky planets close to red and ir stars, the thermodynamics do not favor Earth levels of complexity. This has basically blind to the life that does exist, just that the number of clearly distinguishable biotypes will be lower. 

Edited May 1, 2016 by PB666

[todofwar]

1 hour ago, PB666 said:

See other thread, yes chemosythetic might use a combination of short  ir or deep red along with chemosynthetic in highly select circumstances, might generate O2 that would not acculate because of the overall reducing potential, but I think life is a foregone conclusions in many systems, including large rocky planets close to red and ir stars, the thermodynamics do not favor Earth levels of complexity. This has basically blind to the life that does exist, just that the number of clearly distinguishabel biotypes will be lower. 

Yeah, brown dwarf or red dwarf the issues are similar. I agree that any life will be limited in complexity or diversity, and thus will be very fragile. 

[Bill Phil]

Stars emit light on almost all parts of the visible spectrum. Even red dwarfs aren't actually red.

[PB666]

14 hours ago, Bill Phil said:

Stars emit light on almost all parts of the visible spectrum. Even red dwarfs aren't actually red.

Yes but there has to be enough of that life to allow growth via terribly inefficient chloropylls in plants

[Bill Phil]

28 minutes ago, PB666 said:

Yes but there has to be enough of that life to allow growth via terribly inefficient chloropylls in plants

That's irrelevant. The real determination of enough light is the distance from the star. 

[PB666]

2 hours ago, Bill Phil said:

That's irrelevant. The real determination of enough light is the distance from the star. 

Yes but there is the heat/usable wavelength ratio, most briwn dwarfs are the size of jupiter with much higher masses, that means the light disk is pretty small, the planet need to be close, its orbit would be tidally locked, one surface would have to be very hot most of the incoming radiation is IR, heat. Too hot for life. 

Seriously how much science do you thing is looking  for life around monostellar brown dwarf systems. Our earth ran 3 billion years to produce complex organisms, a brown dwarfs red phase last long enough to burn through lithium, after that it slowly dims down into the infrared.  If you wanted to create a system that was pretty much secure from stellar death and you had a away of fusing hydrogen into deuterium to make an intenal star like the genesis moon, then a brown dwarf a safe distant would be the place, you are virtually invisible, and the heat signature would be invisible in the absorbtion emmision spectrum of radiation fromnthe brown dwarf. 

[John JACK]

Plants adsorb very low percentage of sunlight. Chlorophyll use only narrow band of deep-red light and some blue light. Most abundant green light is just reflected, and IR too. The reason is not energy for photosynthesis, the reason is overheating. Black thing in bright sunlight can heat up to boiling water, to plants it will be obviously deadly. Plant may evaporate some water to control heat, but it's easier just to reflect excess light/energy/heat.

Green Earth plants grow pretty well in monochrome red light. Blue is mostly to control growing and flowering cycles, and other wavelengths are just useless. Under red sun our green plants will thrive, thought may not bear fruit well.
Endemic plant colouration should mostly depend on distance to sun and average temperature. Closer and warmer planets may have bright green or yellow (to reflect more red light) growth, farther and colder — more dark green to brown. Though not black leaves, they both overheat at day and radiate too much warmth at night.

[todofwar]

1 hour ago, John JACK said:

Plants adsorb very low percentage of sunlight. Chlorophyll use only narrow band of deep-red light and some blue light. Most abundant green light is just reflected, and IR too. The reason is not energy for photosynthesis, the reason is overheating. Black thing in bright sunlight can heat up to boiling water, to plants it will be obviously deadly. Plant may evaporate some water to control heat, but it's easier just to reflect excess light/energy/heat.

Green Earth plants grow pretty well in monochrome red light. Blue is mostly to control growing and flowering cycles, and other wavelengths are just useless. Under red sun our green plants will thrive, thought may not bear fruit well.
Endemic plant colouration should mostly depend on distance to sun and average temperature. Closer and warmer planets may have bright green or yellow (to reflect more red light) growth, farther and colder — more dark green to brown. Though not black leaves, they both overheat at day and radiate too much warmth at night.

This was what I was trying to get at, there is definitely more to a pigment than absorption cross section. The other half is the ability to generate charge seperation, which chlorophyll in photosystem ii is great at. So even if it ends up reflecting high energy green light, which seems ineffective, it is able to more efficiently use the photons it does absorb. Under a red sun you may see things evolving to harness red light more effectively, but it doesn't mean they absorb the red light. Avoiding overheating and getting good charge separation efficiency will impact the ultimate color of these hypothetical plants as much as anything. But in terms of evolution, my understanding is life started off chemosynthetically, then developed photosynthesis as a way to deal with solar radiation. I think there would have to be a certain threshold of energy coming in as light for this to evolve naturally. And once you have that much light, I don't know if the planet will be at the right temperature for water to be liquid. 

[Bill Phil]

1 hour ago, PB666 said:

Yes but there is the heat/usable wavelength ratio, most briwn dwarfs are the size of jupiter with much higher masses, that means the light disk is pretty small, the planet need to be close, its orbit would be tidally locked, one surface would have to be very hot most of the incoming radiation is IR, heat. Too hot for life. 

Seriously how much science do you thing is looking  for life around monostellar brown dwarf systems. Our earth ran 3 billion years to produce complex organisms, a brown dwarfs red phase last long enough to burn through lithium, after that it slowly dims down into the infrared.  If you wanted to create a system that was pretty much secure from stellar death and you had a away of fusing hydrogen into deuterium to make an intenal star like the genesis moon, then a brown dwarf a safe distant would be the place, you are virtually invisible, and the heat signature would be invisible in the absorbtion emmision spectrum of radiation fromnthe brown dwarf. 

Why are you talking about brown dwarfs? I'm referring to red dwarfs. They last quite a while. 

And, actually, any life is complex. It took a few hundred million years for some of the first life to come about.

[PB666]

6 minutes ago, todofwar said:

This was what I was trying to get at, there is definitely more to a pigment than absorption cross section. The other half is the ability to generate charge seperation, which chlorophyll in photosystem ii is great at. So even if it ends up reflecting high energy green light, which seems ineffective, it is able to more efficiently use the photons it does absorb. Under a red sun you may see things evolving to harness red light more effectively, but it doesn't mean they absorb the red light. Avoiding overheating and getting good charge separation efficiency will impact the ultimate color of these hypothetical plants as much as anything. But in terms of evolution, my understanding is life started off chemosynthetically, then developed photosynthesis as a way to deal with solar radiation. I think there would have to be a certain threshold of energy coming in as light for this to evolve naturally. And once you have that much light, I don't know if the planet will be at the right temperature for water to be liquid. 

But they can't help but absorb infrared, since almost all organics have absorption bands in the IR spectrum effectively they saturate the IR spectrum with absorption. If the spectrum shifts from green to a center in IR, it means to get the equivilent dose of Orange/Red or Red light in chlorophyll a or B the planet would have to be 2 or 3 times as close as our earth is the its star, much closer with a brown dwarf since output markedly drops.

For a plant or animal to absorb in the visible spectrum typically requires a photophore, the pigments are typically multiring systems in which the resonance stabilization of 4n+2 is spread across many atoms, there is many of these low energy orbitals with tiny shifts energy shifts from the lowest to the next to lowest state. For the smaller energy difference you want to capitalize upon, the larger the ring complex should typically be or the more exotic the metal in the complex. This is not an absolute rule but it is a general rule, The problem in the IR spectrum is that many things absorb, but nothing drops electrons or changes oxidation state (such as a chelated metal) So if you managed to have an agent that absorbs, it has to get to the IR before the all the mileau of it-just-got-hotter compounds absorb it. 

A deep red star or brown dwarf is going to have most of its energy produced in the IR spectrum. Cold brown dwarfs will produce no light they will look sort of purplish because of some UV/blue production and a trace of red, not going to support photosynthesis no matter how close the planet gets.

 

[PB666]

7 minutes ago, Bill Phil said:

And, actually, any life is complex. It took a few hundred million years for some of the first life to come about.

We are talking about multicellular organism with embryogenesis and differentiation. C. elegans or above in complexity.
Most complexity prior to this would have been commensal bacteria living in close proximity in substrates like mud. The cyanobacterium form massive stone colonies.

While we can argue that some cyanobacteria are multicellular, the produce a N fixing structure, that particular structure is not obligatory for their growth, its essentially a stress response do to the lack on bio-available nitrogen. And most importantly that is a common characteristic of simple eucaryotes, they typical take up mating and reproduction when stressed, as a response to produce spores which are more resilient to drastic environmental change. Even in c. elegans, when a female is stressed for food, she simply stops laying eggs, the eggs hatch inside of her and the young eat their way out, if they still cannot find food they go dormant for a time and can extend their lives. They have found bacteria around deep oil formations that basically went into hibernation 100,000s of years ago when the oxygen donors disappeared that are still viable. This is the nature of simple life on a planet were predation is much less of a problem than productivity. Predation will be much less of a problem when there is no oxygen.  For complex life to exist there is a somewhat essential requirement of consistency in a food supply at least stepping from reproductive cycle to the next (e.g. even in our arctic a fatty bear can hibernate and produce offspring until there is adequate food available to restock fat). But that is not were the core of complex life evolution is, this is in the tropic, because high levels of production support diversity and complex food webs.

Most of the ediacara biota that are notable, quickly went extinct. To some paleontologist it might be difficult to consider these as complex, because some have proposed that these could have been single cells, or opportunistic arrangement of single cells. I don't think anyone is going to debate the point that a planet with water and a source of hot springs or deep ocean hydrothermal vents is going to produce life forms, this potentially could happen in deep space with a large enough rock. As I previously said around a hot brown dwarf or deep red star you could have life living around hot vents at the surface that also evolve to use photosynthesis and you could have the development of complexity as oxygen levels in the hot water (very low) accumulated, you could have life venturing between the pools and the atmosphere or grabbing bubbles that are released and float up.

There should be millions of these type planets in our galaxy, for the most part most of these orbit so far from their host stars we will never see them, or they orbit massive giant planets or binaries with brown dwarves. But to go beyond this common thing to something more interesting, even something as high as the Cambrian explosion, that is considerably more difficult. As of yet we still have not found one planet with O2/N2 atmosphere. So the empirical evidence strongly suggests that the set of appropriate circumstances are relatively rare and probably cluster tightly around the paleogeology and climatology of our ancient Earth.