CASPER, Wyo. — People from across the country flocked to places like Casper to catch an August 21, 2017 total solar eclipse.
A University of Wyoming doctoral student studied the effects of the total eclipse on big sagebrush.
Daniel Beverly, a UW botany and hydrology doctoral student, found that the eclipse reduced big sagebrush’s photosynthesis and transpiration and interrupted the plants’ circadian rhythm, according to a June 20 UW news release.
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“He found that the short period of darkness caused a significant reduction in photosynthesis and transpiration in the desert shrub, but not quite to the levels of nighttime,” the announcement states.
“Additionally, the circadian rhythm — the response to the internal clock common to nearly all organisms including humans — was interrupted by the sudden changes in sunlight beyond typical cloud cover.”
Beverly’s research was published in Scientific Reports, UW added.
“’The reduced temperature and lack of sunshine shocked the circadian clock of big sagebrush, triggering a response far beyond what happens when clouds block sunlight,’” Beverly said in the release.
“’However, the duration of eclipse totality was not sufficient to bring the plants completely to their nighttime state.’”
Beverly conducted fieldwork southeast of Yellowstone National Park.
“That area is dominated by mountain big sagebrush,” UW said. “The site experienced 2 minutes, 18 seconds of eclipse totality, with the total duration of partial and total solar eclipse reaching 2 hours, 45 minutes, 36 seconds.”
Beverly used various devices to monitor the effects of the eclipse on the plants. Those included a micrometeorological tower which was used to “record the sun’s radiation and changes in temperature,” according to UW.
To measure photosysnthesis, Beverly used an infrared gas analyzer and he used flurometers analyze how the leaves of the sagebrush responded to the changing light conditions.
“During the short duration of near darkness, they found significant reductions in transpiration — evaporation of water from sagebrush leaves — as well as photosynthesis, the transformation of light energy into chemical energy that converts carbon dioxide and water into sugar and oxygen,” UW continued.
Beverly and fellow researchers also found that there was a 14% reduction in carbon conversion across big sagebrush ecosystems in the West on the day of the eclipse, UW said.
“’Despite its relatively short duration, the eclipse caused a significant reduction in estimated daily carbon uptake for Aug. 21, 2017, in big sagebrush ecosystems,’ Beverly says. ‘This information gives us a more comprehensive understanding of plant physiological responses to sudden changes in light, temperature and humidity that the internal clock fails to predict.’”
Beverly’s research joins work that other scientists did to study the effects of the eclipse on animals.
“Those findings have been mixed, with birds, bees and spiders behaving just as they do at dusk, while no behavioral change was observed in animals such as dairy cattle and captive chimpanzees,” UW said.
“On the other hand, very little is known about plant responses to eclipses, either on the small scale or across broad ecosystems. Beverly’s study — which involved fellow UW scientists in the Department of Botany, the Program in Ecology and the Wyoming Geographic Information Science Center — offers some of the most detailed information about individual plant response and potential broad ecosystem impacts ever reported.”
This article contains photos of the total solar eclipse and of those who came to Casper to gaze upon it.