Why all the AI's for sale?

[tripsandfalls]

Originally Posted by Jakegr

Just a slight correction. Chlorophylls a and b absorb best at about 475 and 680 nm. They utilize energy from 680 nm photons more efficiently than at 475 nm as the former have an energy content closely matching the ideal level of chlorophyll excitation. In terms of growth, we are primarily concerned with chlorophylls a and b. The more colourful pigments (carotenoids) serve more of a photoprotective role and do not have a major impact on growth, at least in algae.

Sure re: carotenoids. I was always under the impression that they also act as accessory pigments, extending the range of wavelengths absorbed to drive photosynthesis. As far as the chlorophylls go, based on their absorption cross section, it looks like they absorb more light at lower wavelengths, so I'm not sure what you mean by the ideal level of chlorophyll excitation. Unless you mean the amount of energy transferred to catalyse oxygen evolution? In which case sure... They dump all the excess energy from the higher energy (shorter wavelength) photons off as heat (via internal conversion).

White LEDs as I'm sure you know are a mix of wavelengths. So you can't say a pigment absorbs best at the wavelengths white LEDs emit, since they emit a very broad spectrum.

Yes, of course. I was thinking yellow for some reason. Should've had a coffee pre-post.

Are you a biologist, or just an enthusiast?