A Mainz study shows that biological soil crusts release large quantities of reactive nitrogen compounds
For a long time now, researchers have been racking their brains over the large quantities of reactive nitrogen compounds observed in arid regions after periods of rainfall without being able to identify the source. A study recently published in the scientific journal entitled “Proceedings of the National Academy of Sciences of the United States of America” (PNAS) is now bringing light into the darkness. Bettina Weber and her colleagues from the Max Planck Institute for Chemistry in Mainz, the Max Planck Institute for Biogeochemistry in Jena and the Biodiversity and Climate Research Center in Frankfurt (BiK-F), were able to prove that biological soil crusts in arid regions emit nitrogen monoxide (NO) and nitrous acid (HONO) when moistened. The two reactive nitrogen compounds play a key role in the production of ozone and OH radicals, which control the atmosphere’s oxidation and self-cleaning properties.
Biological soil crust dominated by lichens and cyanobacteria in the Succulent Karoo, South Africa.
Picture: Bettina Weber
For several years, cryptogam layers composed of soil crusts, among other things, have been causing a stir in earth system and climate research. Indeed, in 2012, a team of researchers led by the Max Planck Institute for Chemistry were able to show that soil crusts are responsible for around half of the biological nitrogen fixation to the Earth’s surface. Bettina Weber and her colleagues took up the question of what happens to the large quantities of fixed nitrogen in the subsequent materials cycle. They have now managed to find their first answer and uncover a hitherto unknown release process for reactive nitrogen compounds.
“Our investigations have shown that biological soil crusts in arid regions release NO and HONO, whereby the quantity corresponds to around 20% of the amount of nitrogen oxides released globally through soils,” explains Bettina Weber, Group Leader in the Multiphase Chemistry Department at the Max Planck Institute for Chemistry, before adding: “While the release of nitrogen monoxide has already been demonstrated in other studies, we have now been able to prove that nitrous acid is also formed and released by biological soil crusts.”
It had previously been assumed that the release of nitrogen monoxide was due to abiotic processes. However, Bettina Weber’s team has now clearly proven that the organisms present in the soil crusts are responsible for the release.
Small-scale power plants in barren regions
“Biological soil crusts are like small-scale power plants,” explains Bettina Weber enthusiastically. “These layers, which are only a few millimeters thick, conceal a concentrate of organisms consisting of producers, consumers and decomposers and thus represent one of the smallest ecosystems in the world. This is where many processes important for the earth system happen in the smallest of spaces.” As the study shows, biological soil crusts in arid regions clearly play a key role in releasing atmospherically reactive nitrogen compounds. “Precipitation plays a major role, since moisture triggers the metabolic process in biological soil crusts,” adds Hang Su, who is also Group Leader in the Multiphase Chemistry Department at the Max Planck Institute for Chemistry and was involved in analyzing the data as a modeler.
Additionally, a team of researchers was recently able to prove, with involvement of the Max Planck Institute for Chemistry, that cryptogam layers also release nitrous oxide and negligible quantities of methane into the atmosphere. “Up until now, cryptogam layers were not included in global climate models. Given the number of new findings concerning how highly influential they are on biogeochemical cycle processes, they can no longer be left out,” summarizes Hang Su.
Biological soil crusts make up around one-ninth of the Earth’s surface. Since it can be assumed that climate change will continue to modify both the occurrence of soil crusts and the distribution and frequency of precipitation, the surface covers should be further examined and the results incorporated into computer models of the global materials cycles.
Dr. Susanne Benner | Max-Planck-Institut für Chemie
Cryo-electron microscopy achieves unprecedented resolution using new computational methods
24.03.2017 | DOE/Lawrence Berkeley National Laboratory
How cheetahs stay fit and healthy
24.03.2017 | Forschungsverbund Berlin e.V.
Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.
The results will be published on March 22 in the journal „Astronomy & Astrophysics“.
Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...
Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.
Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...
In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...
20.03.2017 | Event News
14.03.2017 | Event News
07.03.2017 | Event News
24.03.2017 | Materials Sciences
24.03.2017 | Physics and Astronomy
24.03.2017 | Physics and Astronomy