With information from Cordis – 06/20/2022
Why green nature?
From lawns to great forests, plants on Earth invariably have a pleasant emerald hue.
In fact, the color green is so synonymous with nature and the environment that these words and expressions have been used interchangeably. We often describe ourselves as “thinking green”, “buying green” or wanting a “greener life”.
But why green and what can we learn from that fact?
Who shows why this question is worth asking is biochemist Tobias Erb, a researcher at the Max Planck Institute for Terrestrial Microbiology in Germany.
“Sunlight is a source of energy. This light comes in different flavors, which you can see in a rainbow,” puts Erb in context.
When plants absorb sunlight, they primarily use the blue and red flavors of sunlight as energy to fix carbon dioxide (COtwo), the process called photosynthesis. What’s basically left is the green wavelength, which the plant dispenses and reflects – and that’s what we see.
“Blue light is more energy intensive and penetrates deeper into the water, so it would make sense for the first algae and plants to focus on absorbing this quality of light,” Erb said. At some point—maybe earlier, maybe later—algae and plants gained the ability to also absorb low-energy red light using a different pigment.
So why was green ignored?
Because evolution is based on what already exists and what works, science proposes. Once the first photosynthetic organisms developed the ability to absorb blue and red light and thrived, subsequent plants would have seen little benefit from adding a green pigment.
More energy efficient plants
This current understanding of science of why our world is green could have important ramifications for our future. In the transition to more sustainable energy sources, improving photosynthesis can play a critical role.
“My main motivation as a scientist is to better understand photosynthesis – the biggest and most sustainable energy process of all,” points out Erb. “For over 3 billion years, algae and plants have used sunlight to fix COtwo.”
Evolution, observes the researcher, is a slow process. Human creativity and ingenuity can help us find faster solutions to some of the most pressing environmental problems – like redesigning photosynthesis to harvest more energy from the sun. This is an ongoing collaborative scientific effort, exemplifies Erb, whose team works with artificial photosynthesis.
“So we know that grass is green because it ‘kicks’ that spectrum of light,” he explains. “That means plants only make use of part of the light. What if we created a mechanism by which the entire spectrum of light was captured, which would allow us to fuel photosynthesis even at low light intensities?”
Clues to how this might be possible have been found in the most unlikely places. Aquatic bacteria found at depths of more than 100 meters have developed pigments and elaborate mechanisms for photosynthesizing fragments of light in the cold darkness of the deep sea.
“There are solutions, and we can learn them from the diversity of nature, to reconstruct a more efficient photosynthesis in the laboratory,” asserts Erb.
Other news about: