Pigmentation in Red and Green Algae for Photosynthesis

Extract

[...] They show a lesser absorption in the green range, representing about a third of the total absorption. The most absorbed wavelengths correspond to the most effective spectra, with practically superimposable results. As for red algae, they are distinguished by a strong absorption, in wavelengths ranging from 450 to 600 nm, covering both blue and green. However, they absorb little in red wavelengths, except for those close to 700 nm (over 600 nm). The most effective radiations for them are between 500 and 600 nm (green radiation). [...]

[...] Deduce from this the interest of the particular pigmentation of red algae The interest of the particular pigmentation of red algae lies in their ability to maximize the absorption of available light in their environment. By efficiently absorbing blue and green wavelengths, as well as certain red wavelengths, they can exploit a wider range of the light spectrum for photosynthesis. This pigmentary adaptation allows them to thrive in environments where light is often filtered or attenuated, such as marine depths or shaded areas. By absorbing available wavelengths with great efficiency, they can maximize the production of energy necessary for their growth and survival. [...]

[...] As light descends into the water, it undergoes a phenomenon of absorption. Radiations of a wavelength of 550 nm, corresponding to green-yellow, penetrate the deepest into the water (up to a depth of 28 m). Thus, beyond a depth of 28 m underwater, complete darkness prevails. In the first meters, visible light is relatively well preserved. Red radiations (600 to 700 nm) are the first to be absorbed. This is why shallow waters often appear blue. At 10 m depth, all radiations from 605 to 700 nm are absorbed. [...]