Scientists Observe Mysterious Fluorescent 'Glow' In Forests That Signals Coming Of Spring

A spectrometer system mounted on a tower in Colorado. Researchers found a way to use satellites to more accurately predict how much carbon dioxide are being stored by evergreen forests. The findings could help scientists monitor how forests around the world respond to climate change.   ( Troy Magney )

Forests store large amounts of carbon dioxide, a greenhouse gas that traps heat into the atmosphere and causes an increase in global temperature.

To help combat climate change, a team of researchers has figured out a way to use satellites to monitor the Gross Primary Production or GPP, the amount of chemical energy produced through photosynthesis, in evergreen forests. By monitoring photosynthesis and GPP, scientists can more accurately track levels of global CO2.

Tracking How Much CO2 Forests Store From Space

The current method of tracking GPP is by using satellites and observing the colors of trees change every season. During fall and winter, the leaves of deciduous plants turn brown and fall to the ground when they are dormant. This also means that the forests go through a process similar to hibernation, switching off photosynthesis to conserve energy and survive winter.

However, evergreen plants do not turn brown even during the colder, darker months. This prevents scientists from predicting the rise or decline of photosynthesis on a large scale.

In a study published in the Proceedings of the National Academy of Sciences, researchers proposed tracking solar-induced fluorescence (SIF) to monitor the GPP and photosynthesis of evergreen trees.

SIF is the glow that occurs when chlorophyll levels of the plant return to its normal state and emit a photon. This glow is not visible to the naked eye, but it can be picked up by satellites.

For the study, the researchers used a scanning spectrometer to measure the glow of an evergreen forest in Colorado. They reported that in the springtime, evergreens activate chlorophyll in their needles, which drives an increase in photosynthesis and fluorescence, closely matching satellite measurements of SIF.

The researchers also found that plants deploy a "sunscreen," photoprotective pigments that reduce photosynthesis and fluorescence, during winter. This serves as further proof that scientists can measure SIF to monitor how much carbon dioxide is being stored in evergreen forests.

War Against Climate Change

By monitoring the GPP in both evergreen and deciduous forests, scientists can more accurately monitor the impacts of climate change.

"Ultimately, measuring the small fluorescent glow from plants will allow us to see exactly timing and magnitude of carbon uptake from the terrestrial biosphere," stated Troy Magney, a research scientist at the NASA Jet Propulsion Laboratory. "This will help us understand how forests are responding to climate change and suggest how they might respond to future climate change."

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