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| Titel |
Photoautotrophic organisms control microbial abundance and diversity in
biological soil crusts |
| VerfasserIn |
Alexandra Tamm, Stefanie Maier, Dianming Wu, Jennifer Caesar, Timm Hoffman, Martin Grube, Bettina Weber |
| Konferenz |
EGU General Assembly 2017
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 19 (2017) |
| Datensatznummer |
250153764
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| Publikation (Nr.) |
 EGU/EGU2017-18781.pdf |
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| Zusammenfassung |
| Vascular vegetation is typically quite sparse or even absent in dryland ecosystems all over the
world, but the ground surface is not bare and largely covered by biological soil crusts
(referred to as biocrusts hereafter). These biocrust communities generally comprise
poikilohydric organisms. They are usually dominated by photoautotrophic cyanobacteria,
lichens and mosses, growing together with heterotrophic fungi, bacteria and archaea in
varying composition. Cyanobacteria-, lichen- and moss-dominated biocrusts are known to
stabilize the soil and to influence the water budgets and plant establishment. The autotrophic
organisms take up atmospheric CO2, and (cyano-)bacteria fix atmospheric nitrogen. The
intention of the present project was to study the relevance of the dominating photoautotrophic
organisms for biocrust microbial composition and physiology. High-throughput sequencing
revealed that soil microbiota of biocrusts largely differ from the bacterial community in bare
soil. We observed that bacterial and fungal abundance (16S and 18S rRNA gene copy
numbers) as well as alpha diversity was lowest in bare soil, and increasing from
cyanobacteria-, and chlorolichen- to moss-dominated biocrusts. CO2 gas exchange
measurements revealed large respiration rates of the soil in moss-dominated biocrusts, which
was not observed for cyanobacteria- and chlorolichen-dominated biocrusts. Thus, soil
respiration of moss-dominated biocrusts is mainly due to the activity of the microbial
communities, whereas the microorganisms in the other biocrust types are either dormant or
feature functionally different microbial communities. Our results indicate that biocrust
type determines the pattern of microbial communities in the underlying soil layer. |
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