Plant Glow and Carbon: ESA May Investigate Photosynthesis From Space

The European Space Agency (ESA) is working hard to help scientists better understand and manage the Earth's plant life. On Tuesday, the agency moved to introduce the world to FLEX, a novel approach that could help experts assess the health of vegetation across the globe by measuring their photosynthetic activity from space.

In the wake of climate change, many experts are scrambling to determine how the world will cope with factors like man-made carbon emissions and increasing natural methane release from ocean floors. To make accurate predictions, however, they first need to have a better picture of our planet's carbon cycle, and that requires understanding to what extent plants absorb carbon through photosynthesis.

To help aid that endeavor, NASA previously introduced two Earth Venture Instruments, which measure the prevalence of phytoplankton (the countless plant-like organisms that fill our seas) and the density of forests.

Now, the ESA is stepping up to the plate, having recently announced its latest Biomass mission, which will provide an even more in-depth global snapshot of vegetation between 2020 and 2025. You can read more about that here.

That mission aims to improve the accuracy of previous models even further, using penetrating radio waves to fully account for forest cover and density across the globe. However, there is still one factor that must be considered. (Scroll to read on...)

Researchers now understand that some forests and other vegetation absorb more carbon than others. The efficiency at which a forest acts as a carbon sink can even change from year-to-year, depending on the health and loneliness of its trees.

That's where a new proposed project, called Fluorescence Explorer (FLEX), comes in.

You may not know it, but every plant on the good green Earth glows faintly when undergoing photosynthetic activity. This glow, called fluorescence, occurs only in daylight conditions, and cannot be seen by the naked eye. However, imaging spectrometers tuned to pick up the two specific light wavelengths of plant action can easily pick it out.

In recent FLEX investigations, the ESA has determined that stressed plants (i.e. those sprinkled with herbicide) glow brighter than healthy ones. This is largely because an unhealthy plant does not conduct photosynthesis as efficiently and thus cannot convert as much of the solar radiation it has absorbed into energy. This radiation then winds up being released back into the world as a near-infrared signal.

"FLEX would allow us to measure this fragile red signal and its variations over fields and large agricultural units," Micol Rossini from University of Milan explained in a statement. (Scroll to read on...)

His hope is that the ESA will select the FLEX project to be the focus of its eighth Earth Explorer orbital craft.

"Getting information from space to generate detailed and global maps of plant health and vegetation stress under changing environmental conditions would be a quantum leap in science," Rossini added.

With the resulting data, the FLEX team hopes to essentially use a triage system on forests, highlighting forests that are undergoing the most stress first, so that smarter management of these essential, but limited resources can be put into place.

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