It is well known that the rainforests are crucial for the global climate – but not only the mighty canopy, but also the much more inconspicuous mosses and lichens contribute to this.
Not to be underestimated in times of climate change
In the shade of the huge trees and the undergrowth in the rainforests, you can easily overlook them: the lichens and mosses that cover a large part of the tree trunks, lianas and sometimes even the leaves of the ever-humid forests in the tropical climate zone. Worldwide they contribute about seven percent to the binding of harmful carbon dioxide, with nitrogen the binding even amounts to around 50 percent, announced the University of Graz.
In times of climate change, the importance of this should by no means be underestimated, emphasizes Bettina Weber, professor at the Institute for Biology at the University of Graz: The biologist has worked with scientists from the Max Planck Institute for Chemistry in Mainz and the Brazilian Instituto Nacional de Pesquisas da Amazônia in Manaus examined the situation in rainforests over a period of two years (2016 and 2018) and published the findings in the journal “Nature Communications Earth & Environment”.
Extrapolated, values similar to those for trees
“We measure volatile organic compounds emitted by the rainforest at different heights,” reported Jonathan Williams, group leader at the Max Planck Institute for Chemistry in Mainz. “If you extrapolate the amount of emissions from mosses and lichens, you get values similar to those of trees,” sums up Achim Edtbauer, scientist at the Max Planck Institute for Chemistry and first author of the study.
As the researchers realized, mosses and lichens produce significant amounts of chemical compounds of the sesquiterpenoid type. These react quickly with ozone and form oxygenated compounds and particles in the air. Overall, these processes influence cloud formation and precipitation, they also trigger the self-cleaning power of the earth’s atmosphere. Extrapolated to the global area of tropical rainforests, lichens and especially mosses, which emit almost ten times as much as lichens, are likely to make a substantial contribution to global sequiterpenoid emissions.
Follow-up studies important
Follow-up studies, which measure the exchange of volatile organic compounds of mosses and lichen under controlled laboratory conditions, are important, said Bettina Weber: She wants to further clarify which role temperature, light and humidity play in the release of the sesquiterpenoids. In this way, their emissions could be integrated into atmospheric and climate models, for example in order to more accurately map the effects of drought on the rainforest.
“Curb desertification”
It has already been recognized that a community of mosses, lichens, fungi, cyano and other bacteria are very important for the consolidation of soils in arid regions. Bettina Weber also confirms this on the basis of her research work: “They actually fix the substrate very effectively and slow down desertification. For example, fungi and cyanobacteria surround grains of sand and stick them with slime ”. This would prevent the wind from being carried away, bring in nutrients and at the same time create the basis for other plants.
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