TY - JOUR
T1 - Divergence of Biocrust Active Bacterial Communities in the Negev Desert During a Hydration-Desiccation Cycle
AU - Baubin, Capucine
AU - Ran, Noya
AU - Siebner, Hagar
AU - Gillor, Osnat
N1 - Funding Information:
This study was partially supported by the Israel Science Academy, grant no. 993/11.
Publisher Copyright:
© 2022, The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.
PY - 2022/7/5
Y1 - 2022/7/5
N2 - Rain events in arid environments are highly unpredictable and intersperse extended periods of drought. Therefore, tracking changes in desert soil bacterial communities during rain events, in the field, was seldom attempted. Here, we assessed rain-mediated dynamics of active bacterial communities in the Negev Desert biological soil crust (biocrust). Biocrust samples were collected during, and after a medium rainfall and dry soil was used as a control; we evaluated the changes in active bacterial composition, potential function, potential photosynthetic activity, and extracellular polysaccharide (EPS) production. We hypothesized that rain would activate the biocrust phototrophs (mainly Cyanobacteria), while desiccation would inhibit their activity. In contrast, the biocrust Actinobacteria would decline during rewetting and revive with desiccation. Our results showed that hydration increased chlorophyll content and EPS production. As expected, biocrust rewetting activated Cyanobacteria, which replaced the former dominant Actinobacteria, boosting potential autotrophic functions. However, desiccation of the biocrust did not immediately change the bacterial composition or potential function and was followed by a delayed decrease in chlorophyll and EPS levels. This dramatic shift in the community upon rewetting led to modifications in ecosystem services. We propose that following a rain event, the response of the active bacterial community lagged behind the biocrust water content due to the production of EPS which delayed desiccation and temporarily sustained the biocrust community activity.
AB - Rain events in arid environments are highly unpredictable and intersperse extended periods of drought. Therefore, tracking changes in desert soil bacterial communities during rain events, in the field, was seldom attempted. Here, we assessed rain-mediated dynamics of active bacterial communities in the Negev Desert biological soil crust (biocrust). Biocrust samples were collected during, and after a medium rainfall and dry soil was used as a control; we evaluated the changes in active bacterial composition, potential function, potential photosynthetic activity, and extracellular polysaccharide (EPS) production. We hypothesized that rain would activate the biocrust phototrophs (mainly Cyanobacteria), while desiccation would inhibit their activity. In contrast, the biocrust Actinobacteria would decline during rewetting and revive with desiccation. Our results showed that hydration increased chlorophyll content and EPS production. As expected, biocrust rewetting activated Cyanobacteria, which replaced the former dominant Actinobacteria, boosting potential autotrophic functions. However, desiccation of the biocrust did not immediately change the bacterial composition or potential function and was followed by a delayed decrease in chlorophyll and EPS levels. This dramatic shift in the community upon rewetting led to modifications in ecosystem services. We propose that following a rain event, the response of the active bacterial community lagged behind the biocrust water content due to the production of EPS which delayed desiccation and temporarily sustained the biocrust community activity.
KW - Actinobacteria
KW - BSC
KW - Chlorophyll
KW - Cyanobacteria
KW - EPS
KW - Rain
UR - http://www.scopus.com/inward/record.url?scp=85133427654&partnerID=8YFLogxK
U2 - 10.1007/s00248-022-02063-z
DO - 10.1007/s00248-022-02063-z
M3 - Article
C2 - 35788422
AN - SCOPUS:85133427654
SN - 0095-3628
VL - 86
SP - 474
EP - 484
JO - Microbial Ecology
JF - Microbial Ecology
IS - 1
ER -