Space station instrument provides new details on plant drought resistance

Space station instrument provides new details on plant drought resistance

A new instrument on the International Space Station is helping scientists understand the inner workings of plant life by showing how different plants balance the trade-off between growth and water use. A team of scientists has now conducted a major global study of these trade-offs between nine different plant types in 11 ecosystems around the world.

In this first-of-its-kind study, the authors found that the same types of plants, such as deciduous broadleaf trees, evergreen conifers, tall and low shrubs, herbs and non-herbaceous herbs, generally had similar water-use efficiencies, no matter where they were grown. The results showed that it was the type of plants, not the climate in which they were grown, that determined their efficiency. The results also showed that longer-lived plant types such as shrubs and trees were more water-use efficient than shorter-lived grasses.

The authors say this study shows how environmental conditions affect current and future plant communities and the ecosystem services they provide.The results have just been published in the journal natural plants.

When plants absorb carbon dioxide for photosynthesis and growth, they both consume and lose water. Species that can grow more while using less water may be more resilient to the projected increases in the frequency, intensity and duration of droughts in many regions due to global climate change.

“Understanding how different plant types optimize the trade-off between growth and water use can inform plans to mitigate and adapt to a warmer and drier future,” said lead author Savannah, a Columbia University doctoral student and NASA Jet Propulsion Laboratory contractor Cooley said.

Plant water usage in San Juan, Argentina, December 2, 2020, captured by the ECOSTRESS instrument. Blue indicates high water usage (such as in farmland and mountains), and beige indicates dry conditions (such as in the surrounding desert).Image: NASA’s Jet Propulsion Laboratory

The analysis was made possible by data from a new satellite instrument, the ECOsystem Space Station Onboard Thermal Radiometer Experiment or ECOSTRESS. The instrument provides the most detailed images of Earth’s surface temperature ever acquired from space. These temperature images are used to estimate the rate of evapotranspiration (transfer of water from the surface to the atmosphere) and photosynthesis by plants. Previously, the lower resolution of available data and disagreements between different surface models led to large differences in measures of water use efficiency.

The researchers said ECOSTRESS revealed patterns that previous satellite instruments could not observe, and that could not be measured on the ground. For example, using imagery from the Brazilian Amazon, the study showed marked differences in water-use efficiency across plant types within miles of seemingly similar tropical rainforests, as well as sudden changes in forest conversion to pasture.

Built by the Jet Propulsion Laboratory and launched in 2018, the system provides global surface temperature information with unprecedented spatial and temporal resolution. It sends images every two to three days at a resolution lower than a football field.

“ECOSTRESS is extraordinary in that it allows us to determine plant water use almost anywhere on Earth on a spatial scale that would have been unimaginable just a few years ago, all from a single source of water more than 250 miles above us at more than 17,000 per hour. mile,” said study co-author Joshua Fisher of Chapman University. The measurements could also help detect wildfires, urban heatwaves, volcanic activity, and many other applications, the authors say.

The study was also co-authored by Gregory Goldsmith of Chapman University.

Adapted from a press release from Chapman University.