Ecologists conducted a novel study on vegetation transpiration from a global network of 251 sites
2021-01-28
(Press-News.org) An ecologist from RUDN University together with colleagues from 14 countries compared three methods for estimating ecosystem transpiration in a study. In the first ever research with such a comprehensive data-set, the team used land-atmosphere water vapor flux data of collected at 251 locations all over the planet, from Australia to Greenland. The outcome of the research help to understand the role of plants in the global water and carbon cycles in the current predicament of global warming. The results of the study were published in the December 2020 issue of the journal Global Change Biology.
Plants roots absorb water from the soil and transport through the stems up to their leaves thanks to a gradient of water vapor pressure. Once it reaches the leaves, water evaporates through leaf pores called stomata and gets into the atmosphere. The physical process by which water is released to the atmosphere by plants is called transpiration. Transpiration is a 'meeting point' of carbon, water, and energy cycles in terrestrial ecosystems, since plants need water for fixing atmospheric CO2 by photosynthesis and convert a large fraction of the solar energy input into this process, therefore by improving the modelling of transpiration scientists can analyze the role of vegetation in climate change scenarios. An international group of scientists led by Dr. Jacob Nelson from the Max Planck Institute for Biogeochemistry (Germany) and including an ecologist from RUDN University, compared three methods for estimating ecosystem transpiration based on micrometeorological data from FLUXNET--a global network of stations.
The team used the data collected at 251 FLUXNET sites. Among many environmental physical and chemical parameters, these stations provide continuous flux measurements of water vapor and carbon dioxide between the monitored ecosystems and the atmosphere. To do so, the eddy covariance method is applied, that relies on the three-dimensional monitoring at high frequency of turbulent flows of trace gases. The team chose three methodological approaches to retrieve transpiration from the eddy covariance data and used independent tree sap flow measurements from six test sites to compare the transpiration estimates.
"All three methods are based on the ratio between evapotranspiration and fluxes of carbon uptaken by photosynthesis from the atmosphere, that is termed water use efficiency, and differ by initial assumptions and parameterization. At daily scale, transpiration estimates yielded by the three methods were highly correlated, between 89 and 94%. However, the ratio of transpiration to evapotranspiration differed across models ranging from 45% to 77%." said Dr. Luca Belelli Marchesini researcher at the Agrarian and Technological Institute of RUDN University (Russia) and at the Fondazione Edmund Mach (Italy).
Having further analyzed the results in search of driving factors, the team concluded that the geographic variation in the transpiration to evapotranspiration ratio (T/ET) was mainly controlled by vegetation and soil characteristics rather than by climatic variables such as temperature and precipitation.
To explain the relative stability of T/ET among sites, the team suggested two hypotheses. The first consists in a trade-off between the amount of precipitation intercepted by vegetation canopies and soil evaporation: ecosystems with a dense leaf cover, not limited by water availability, would thus intercept more rain and soil evaporation would be reduced. In contrast, water limited ecosystems, characterized by a smaller vegetation cover, would have a larger fraction of water evaporated from the soil.
According to the second hypothesis, ecosystems tend to adapt to the available water resources, therefore, for instance, vegetation in dry climates would improve the utilization of the limited precipitation, thus increasing the T/ET ratio.
'The combination of these two hypotheses likely explains the relative stability of the T/ET ratio in different ecosystems. This study represents the first extensive estimate of ecosystem transpiration based on in-situ data and allows shedding new light on the role of plants' water use in the context of the global water and carbon cycles" added Dr. Luca Belelli Marchesini.
INFORMATION:
[Attachments] See images for this press release:
ELSE PRESS RELEASES FROM THIS DATE:
2021-01-28
Western Carolina University researchers find a disproportionate number of inmates with violent offenses suffer from post-traumatic stress disorder, panic disorder and alcohol use disorder, and published their findings in the Journal of Criminal Psychology.
Alexa Barrett, clinical psychology master's student at WCU, and Al Kopak, associate professor of criminology and criminal justice at WCU, discovered the combination of PTSD, PD and AUD significantly increased the likelihood of violent offenses while conducting research at three county detention centers in North Carolina.
Supported by a Summer Research Assistantship provided by the Graduate School, the purpose of this study was to detail ...
2021-01-28
A PhD student and 'beer scientist' has inadvertently discovered a way to conduct extremely small-scale brewing experiments, potentially leading to better beer.
It came about when University of Queensland PhD candidate Edward Kerr hit a hurdle when he completed a beer brewing experiment for a paper.
"I was looking at barley protein changes during the mashing stage of beer brewing, when one of the paper's reviewers asked if the changes were caused by temperature or time spent mashing the barley," Mr Kerr said.
"It was a good question, but to find out I'd need to brew all over again, with an instrument that would hold at least 23 litres ...
2021-01-28
WASHINGTON, D.C. and SAN DIEGO, CA -- In his inaugural address, President Joe Biden vowed that "help is on the way" to a nation grappling with a pandemic that has already claimed over 420,000 lives and counting. However, despite the promise of a better future, a new survey from West Health and Gallup finds Americans remain largely skeptical that issues as varied as managing the COVID-19 crisis, lowering healthcare costs, improving the economy, fixing immigration and addressing climate change, will improve anytime soon.
The findings from the monthly West Health-Gallup U.S. Healthcare Study are based on a ...
2021-01-28
Pioneering research into how our bodies manufacture the cells that make blood has moved us closer to regrowing tissues and organs. The findings also may let doctors grow the cells for transplantation into people to battle cancer, blood disorders and autoimmune diseases.
Researcher Karen K. Hirschi, PhD, of the Department of Cell Biology and the Robert M. Berne Cardiovascular Research Center at the University of Virginia School of Medicine, has developed a simple and efficient way to generate "hemogenic endothelial cells." These cells are the first step in the production line of blood cells, and Hirschi's new findings provide a blueprint for creating them outside the body.
"By studying how hemogenic endothelial cells develop normally, we gain insights needed ...
2021-01-28
Ceramic matrix composites (CMCs) are incredibly strong materials used in jet engines, gas turbines, and cutting tools for nickel superalloys. Aluminum oxide (Al2O3) is hard and chemically inert, and tungsten carbide (WC) is used as a superhard material, but past efforts to create an Al2O3-WC CMC yielded unsatisfactory results. Recently, a study by Japanese scientists, published in Scientific Reports, shows that adding zirconium atoms results in improved Al2O3-WC CMCs.
Given the potential utility of Al2O3-WC CMCs as superhard materials, researchers around the world have tested several formulations to identify one with a high bending strength, which is a measure of the physical stress a material can be subjected to before it becomes permanently bent or broken. Previously, ...
2021-01-28
In a first-of-its-kind study, researchers discovered that light pollution leads to more than just wasted energy and washed-out starlight--it can increase the likelihood of a preterm birth by almost 13%. Laura Argys, professor of economics at the University of Colorado Denver, collaborated with scientists at Lehigh University and Lafayette College to produce this study.
Skyglow, the brightness of the night sky apart from discrete light sources such as the moon and visible stars, is one of the most pervasive forms of light pollution. When you have increased artificial brightness at night, coming from sources like streetlamps, outdoor advertising, and buildings, it reduces your ability to see the dark ...
2021-01-28
Aging and lifestyle-related metabolic imbalances, such as hyperglycemia, hyperlipidemia, and oxidative-stress, cause the accumulation of advanced glycation end products (AGEs), including pentosidine (PEN, crosslinked type) and carboxymethyl-lysine (CML, non-crosslinked type). Osteoporosis is a widespread metabolic skeletal disease characterized by diminished bone mineral density (BMD) or bone strength, which increases the risk of fractures.
To date, the association of PEN and CML with osteoporotic fracture has been reported, and the accumulation of AGEs in bone ...
2021-01-28
When it comes to drones, the Singapore public is not as keen for them to be used to provide services around their living spaces, finds a study by researchers at the Nanyang Technological University, Singapore (NTU Singapore). However, they are more accepting of drones being used in areas like recreational spots or industrial areas.
There is growing global interest in the use of drones to provide a range of applications - from building inspection to last mile commercial delivery - that promise productivity gains and cost reductions.
In Singapore, the use of drones is picking up, with the government adopting them for various projects in the Smart Nation drive, where technology ...
2021-01-28
Cambridge, Massachusetts - They may be the youngest astronomers to make a discovery yet.
This week, 16-year-old Kartik Pinglé and 18-year-old Jasmine Wright have co-authored a peer-reviewed END ...
2021-01-28
Across many animal species there is great evolutionary pressure on males, who often engage in combat for the rights to copulation. This phenomenon, called sexual selection, often ends up favoring males with larger weapons, such as horns or pincers. Interestingly, scientists have noted that males endowed with smaller weapons adopt alternative reproductive tactics in some species. For example, instead of fighting other more powerful males, they may try to sneak around or disperse in search of a lonely female.
Variability in sexual behavior according to a male's weapon size has been widely studied. However, it's worth noting that bigger is not always better. Though larger weapons usually help in fights for reproductive rights, they can also be ...
LAST 30 PRESS RELEASES:
[Press-News.org] Ecologists conducted a novel study on vegetation transpiration from a global network of 251 sites
