3 ms·

Wait what??? So 1-2 degrees average is enough to be past peak photosynthesis temperatures? And putting black solar panels is going to bring that back into optim

by paiute 3y ago

Wait what??? So 1-2 degrees average is enough to be past peak photosynthesis temperatures? And putting black solar panels is going to bring that back into optimal range? I can’t see any of that being close to factual. Crops under panels could make a lot of sense but not for any of what you said. solar panels raise the localized temp. Solar panels probably keep the area warmer when the sun is down(heat island effect). They also provide shade. Those things could be good or bad for the crop depending on the crop and the region. It’s hot today, I’m going to open the freezer door to cool the house.

dieselgate 3y ago
At the very least it would be helpful to use a temperature unit when mentioning degrees.
adrian_b 3y ago
Direct solar light is more than any plant can handle, but the plants are adapted to this, which is why the terrestrial plants are green, instead of being black, in order to reflect a large part of the solar light to avoid overheating, even if this reduces the amount of captured energy. On the other hand the oceans are dominated by diatoms and brown algae, which absorb a much greater part of the solar light. There are many plants which are adapted to live in shadows and which would grow well under solar panels, but I do not know if there are many useful crops among them.
- kadoban 3y ago
  > Direct solar light is more than any plant can handle, but the plants are adapted to this, which is why the terrestrial plants are green, instead of being black, in order to reflect a large part of the solar light to avoid overheating, even if this reduces the amount of captured energy. From what I've read, it's more nuanced/complicated than that. It depends on details of how photosynthesis works rather than just being a simple heat effect. https://www.quantamagazine.org/why-are-plants-green-to-reduce-the-noise-in-photosynthesis-20200730/ https://www.quantamagazine.org/why-are-plants-green-to-reduc...
  - adrian_b 3y ago
    It is true that the reasons why phototrophy does not work in a too strong light are much more complex than a heat effect, but also the theory proposed in the paper quoted at your link is too simplistic to be convincing. The primary pigment use to capture light in all phototrophic living beings which produce elemental oxygen is chlorophyll a, which is blue-green not green. In the land plants, the blue-green color is masked by the more abundant green chlorophyll b, which is an accessory pigment that transfers the captured energy to chlorophyll a. So if it is assumed that the color of the pigments has influence upon the regulation of the energy flux (as claimed in that paper) and it is not due to historical accidents, then any such theory must explain why when oxygenic photosynthesis has evolved first in Cyanobacteria, most likely in a terrestrial freshwater environment or in intertidal zones, the optimal color was blue-green, not green as claimed in that paper, then when the Cyanobacteria spread in the oceans in environments with lower light levels (where the luminous flux has even greater fluctuations that require regulation, according to the hypothesis from that paper) the algae have evolved to have accessory pigments that absorb most of the available light, and then, when going back to the continents and exposed to strong light, they have replaced the more efficient accessory pigments with a green pigment, which produces a lower amount of photoelectrons at a given illumination. The latter fact is easy to understand as just a means to limit the fraction of captured energy versus total energy (in order to not produce more redox agents than can be used by the chemical syntheses that are limited in speed by other factors), but it does not make sense as a means to supposedly diminish the effect of light fluctuations, because these are much smaller in a more intense light flux, with much more photons per second.
- paiute 3y ago
  Does brown algae(fucoxanthin pigment) really absorb a greater part? Most chlorophyll has a gap in the green spectrum. https://www.mdpi.com/remotesensing/remotesensing-05-06812/article_deploy/html/images/remotesensing-05-06812f2-1024.png https://www.mdpi.com/remotesensing/remotesensing-05-06812/ar...
  - adrian_b 3y ago
    The chlorophylls always have a gap in the green or in the blue-green, where the light is reflected. However, in the non-green algae there are various accessory pigments, which absorb light in bands not used by chlorophyll and which transfer the generated photoelectrons to chlorophyll, enhancing the amount of the light whose energy is captured. The ancestors of the green algae, which adapted to a terrestrial freshwater environment, then to the dry land, becoming land plants, have lost most accessory pigments, because they now received more light than they could use.
mitchellvdub 3y ago
I think you're right it's more the shade that helps the plants than the reduced temp. But there is a reduction in temp caused by the plants which help the solar panels be more efficient. It's a symbiotic relationship. It does depend on the crop and how much light the specific plant requires.
barathr 3y ago
If you are sincerely interested you can read about agrivoltaics. There's lots written about it.

by paiute 3y ago

dieselgate 3y ago

At the very least it would be helpful to use a temperature unit when mentioning degrees.

adrian_b 3y ago

Direct solar light is more than any plant can handle, but the plants are adapted to this, which is why the terrestrial plants are green, instead of being black, in order to reflect a large part of the solar light to avoid overheating, even if this reduces the amount of captured energy. On the other hand the oceans are dominated by diatoms and brown algae, which absorb a much greater part of the solar light. There are many plants which are adapted to live in shadows and which would grow well under solar panels, but I do not know if there are many useful crops among them.

kadoban 3y ago
> Direct solar light is more than any plant can handle, but the plants are adapted to this, which is why the terrestrial plants are green, instead of being black, in order to reflect a large part of the solar light to avoid overheating, even if this reduces the amount of captured energy. From what I've read, it's more nuanced/complicated than that. It depends on details of how photosynthesis works rather than just being a simple heat effect. https://www.quantamagazine.org/why-are-plants-green-to-reduce-the-noise-in-photosynthesis-20200730/ https://www.quantamagazine.org/why-are-plants-green-to-reduc...
- adrian_b 3y ago
  It is true that the reasons why phototrophy does not work in a too strong light are much more complex than a heat effect, but also the theory proposed in the paper quoted at your link is too simplistic to be convincing. The primary pigment use to capture light in all phototrophic living beings which produce elemental oxygen is chlorophyll a, which is blue-green not green. In the land plants, the blue-green color is masked by the more abundant green chlorophyll b, which is an accessory pigment that transfers the captured energy to chlorophyll a. So if it is assumed that the color of the pigments has influence upon the regulation of the energy flux (as claimed in that paper) and it is not due to historical accidents, then any such theory must explain why when oxygenic photosynthesis has evolved first in Cyanobacteria, most likely in a terrestrial freshwater environment or in intertidal zones, the optimal color was blue-green, not green as claimed in that paper, then when the Cyanobacteria spread in the oceans in environments with lower light levels (where the luminous flux has even greater fluctuations that require regulation, according to the hypothesis from that paper) the algae have evolved to have accessory pigments that absorb most of the available light, and then, when going back to the continents and exposed to strong light, they have replaced the more efficient accessory pigments with a green pigment, which produces a lower amount of photoelectrons at a given illumination. The latter fact is easy to understand as just a means to limit the fraction of captured energy versus total energy (in order to not produce more redox agents than can be used by the chemical syntheses that are limited in speed by other factors), but it does not make sense as a means to supposedly diminish the effect of light fluctuations, because these are much smaller in a more intense light flux, with much more photons per second.
paiute 3y ago
Does brown algae(fucoxanthin pigment) really absorb a greater part? Most chlorophyll has a gap in the green spectrum. https://www.mdpi.com/remotesensing/remotesensing-05-06812/article_deploy/html/images/remotesensing-05-06812f2-1024.png https://www.mdpi.com/remotesensing/remotesensing-05-06812/ar...
- adrian_b 3y ago
  The chlorophylls always have a gap in the green or in the blue-green, where the light is reflected. However, in the non-green algae there are various accessory pigments, which absorb light in bands not used by chlorophyll and which transfer the generated photoelectrons to chlorophyll, enhancing the amount of the light whose energy is captured. The ancestors of the green algae, which adapted to a terrestrial freshwater environment, then to the dry land, becoming land plants, have lost most accessory pigments, because they now received more light than they could use.

mitchellvdub 3y ago

I think you're right it's more the shade that helps the plants than the reduced temp. But there is a reduction in temp caused by the plants which help the solar panels be more efficient. It's a symbiotic relationship. It does depend on the crop and how much light the specific plant requires.

barathr 3y ago

If you are sincerely interested you can read about agrivoltaics. There's lots written about it.