Glowing plants?
Although this may sound like something out of a science fiction movie, it is actually a natural process that gives scientists clues about impending droughts.
Flash droughts are exactly what they sound like; They happen quickly and without much warning. An example of this was the summer of 2012, when much of the United States experienced the most severe flash drought since then Dust Bowl from the 1930s that lasted for years.
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Typically, it takes several seasons for a normal drought to develop – but in a sudden drought, an accelerated drought occurs after just a few weeks. Therefore, it is quite difficult to prepare for it. Scientists at NASA’s Jet Propulsion Laboratory in Southern California may have a solution. They have it at the end of April published a study about their discovery of a way to detect signs of sudden drought months in advance. So signs from outer space. You just have to look for the glow – or, well, the lack thereof. It appears that in anticipation of a sudden drought, a plant’s “glow” becomes dimmer, and it is possible to capture this dimmer glow with spacecraft orbiting our planet.
More specifically, this glow is not visible to the human eye, but can be identified by certain instruments onboard satellites NASA’s Orbiting Carbon Observatory-2 (OCO-2).. According to scientists, the plant glow phenomenon has appeared repeatedly in this satellite’s data since 2014, when it arrived in space and began to “see the light” throughout the growing season in the Midwestern United States.
When plants photosynthesize, they bask in sunlight and absorb our star’s rays to convert water and carbon dioxide into food. During this process, some unused photons or light particles escape from the plants’ chlorophyll content, i.e. compounds that give plants their color. This creates a slight shine. This is called “glow”. solar-induced fluorescence (SIF)The SIF becomes brighter when a plant uses more carbon dioxide from the atmosphere to increase its growth.
After looking at and comparing years of fluorescence data with sudden droughts that occurred in the U.S. between May and July from 2015 to 2020, researchers were able to identify a glow-related pattern weeks (and sometimes even months) before a sudden drought happened. Use of data NASA’s Soil Moisture Active Passive (SMAP). The satellite also allowed scientists to detect fluctuations in the amount of water in the plants’ soil by observing the strength of natural microwave emissions emitted by the plants during that period. Each year during the study, from May to July, the plants, on average, bloomed in warm and dry conditions and therefore shone brightly in satellite images.
Then, as water supplies decline in anticipation of a sudden drought, the glow begins to fade. The variance of this atypical pattern closely corresponded with the amount of soil moisture loss six to twelve weeks before a sudden drought in different parts of the country.
“[Plant fluorescence] “shows promise as a reliable early warning indicator of sudden droughts with enough lead time to take action,” said Nicholas Parazoo, geoscientist at JPL and lead author of the current study. said in a statement.
Although this research may not be able to prevent sudden droughts, it still provides forecasters with a slightly better overview so that they can provide important information to those who would be affected by an impending drought.
“Farmers and ranchers with advanced operations can better use water for irrigation to reduce impacts on crops, avoid planting crops that are likely to fail, or plant a different type of crop to get the most ideal yield if they have weeks to months of lead time.” Jordan Gerth, a scientist with the National Weather Service Office of Observations, said in the same statement.
Another part of the study was to learn more about how flash droughts affect carbon emissions. During the photosynthesis process, plants and trees absorb much more carbon dioxide than they release, a crucial portion of carbon dioxide Carbon cycle This includes interactions between land, atmosphere and ocean. Carbon dioxide levels can be determined from OCO-2 satellite data. When scientists then feed this data into advanced computer models, they can determine how much carbon is absorbed by vegetation before and after a sudden drought, the team says.
Ultimately, scientists concluded that there is a “balancing act” when it comes to carbon absorption in the period before and after extreme droughts. The more extreme the heat, the more the plants eat! In the long term, studies like these will likely help researchers improve the predictions of carbon cycle models so we can better understand how plants work and learn even more about how they are affected by extreme weather conditions.