These pigments are reds, oranges, and yellows.. As you saw in your TLC strip, chlorophyll b appears more yellow while chlorophyll a appears more blue. What portion of the spectrum is chlorophyll b absorbing that chlorophyll a is not? Brown algae have chlorophyll a and chlorophyll c, as well as the carotenoid fucoxanthin , which gives them their golden brown color. Compare the available specimens of cyanobacteria, red algae, green algae, and brown algae. What do the colors of these organisms tell you about where they live?
The story is really nothing more than a tale of biological thievery. That moment in evolutionary history is important to Distinguished Professor J. Clark Lagarias, Department of Molecular and Cellular Biology, and his colleagues in the College of Biological Sciences, as it marked the origin of chloroplasts, the cellular structures in plants responsible for photosynthesis.
As every high school biology student learns, photosynthesis is the conversion of light energy into chemical energy. But how can this huge diversity of cyanobacterial pigments be explained? In fact, the scientists have shown that the bonds between atoms in water molecules are subject to vibrations that absorb certain light wavelengths, delimiting spectral niches, i. A new mathematical model, combined with satellite measurements, has confirmed that these vibrations divide the light spectrum into five niches: violet, blue, green, orange and red.
Samples from the Tara Oceans expedition also demonstrated that the different pigment types of cyanobacteria are well distributed according to these niches: the cyanobacterium Prochlorococcus dominates in large central oceanic gyres, while Synechococcus predominates in coastal waters. These results, published in Nature Ecology and Evolution on the 9th November , could improve forecasts on the evolution of aquatic ecosystems in the context of global climate change.
After blooming, the Trichodesmium erythraeum die, and they turn the sea reddish-brown. Vast slick of cyanophyte algae visible from space. The algal cells coalesce in strings and clumps. As the cells age, they become buoyant.
In calm weather, the cells aggregate into huge slicks. The relative abundance of phycobilin pigments, the reddish phycoerythrin and the blue phycocyanin, explain the color of cyanobacteria. Microscopically, the blue phycocyanin pigment, the green chlorophyll, and the accessory pigments give rise to blue-green algae.
Species of cyanobacteria differ in their ratios of phyocyanin and phycoerythrin. The appearance of a body of water changes drastically during a "bloom" of cyanobacteria, but the color is also not always due to pigments alone.
For example, lakes in the Swiss Alps have been known to be turned blood-red by Oscillatoria rubescens blooms because they have refractive pseudovacuoles not bounded by a tonoplast membrane rather than by excessive phycoerythrin.
0コメント