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Water regime history drives responses of soil Namib Desert microbial communities to wetting events.

Frossard A, Ramond JB, Seely M, Cowan DA - Sci Rep (2015)

Bottom Line: The effects of wetting event frequency and intensity on Namib Desert microbial communities from two soils with different water-regime histories were tested over 36 days.T-RFLP data showed that the different wetting events affected desert microbial community structures, but these effects were attenuated by the effects related to the long-term adaptation of both fungal and bacterial communities to soil origins (i.e. soil water regime histories).The intensity of the water pulses (i.e. the amount of water added) rather than the frequency of wetting events had greatest effect in shaping bacterial and fungal community structures.

View Article: PubMed Central - PubMed

Affiliation: Centre for Microbial Ecology and Genomics (CMEG), Genomic Research Institute, University of Pretoria, Pretoria, South Africa.

ABSTRACT
Despite the dominance of microorganisms in arid soils, the structures and functional dynamics of microbial communities in hot deserts remain largely unresolved. The effects of wetting event frequency and intensity on Namib Desert microbial communities from two soils with different water-regime histories were tested over 36 days. A total of 168 soil microcosms received wetting events mimicking fog, light rain and heavy rainfall, with a parallel "dry condition" control. T-RFLP data showed that the different wetting events affected desert microbial community structures, but these effects were attenuated by the effects related to the long-term adaptation of both fungal and bacterial communities to soil origins (i.e. soil water regime histories). The intensity of the water pulses (i.e. the amount of water added) rather than the frequency of wetting events had greatest effect in shaping bacterial and fungal community structures. In contrast to microbial diversity, microbial activities (enzyme activities) showed very little response to the wetting events and were mainly driven by soil origin. This experiment clearly demonstrates the complexity of microbial community responses to wetting events in hyperarid hot desert soil ecosystems and underlines the dynamism of their indigenous microbial communities.

No MeSH data available.


NMDS ordination of fungal and bacterial community structure inferred from OTUs relative abundance (obtained from T-RLFPs from all water treatments and all sampling times combined).Different clusters denotes for communities originated from the riverbed (orange) and the gravel plain (brown).
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f3: NMDS ordination of fungal and bacterial community structure inferred from OTUs relative abundance (obtained from T-RLFPs from all water treatments and all sampling times combined).Different clusters denotes for communities originated from the riverbed (orange) and the gravel plain (brown).

Mentions: The divergence between the two soil origins was clearer in the fungal community where the riverbed and the gravel plain clusters were clearly separated and barely overlapped compared to the bacterial community where the two clusters largely overlapped (Fig. 3). The stronger association of the fungal community structure with the soil origin suggests that desert fungal communities were either more soil-specific than bacterial communities46 or were more resistant to wetting events47.


Water regime history drives responses of soil Namib Desert microbial communities to wetting events.

Frossard A, Ramond JB, Seely M, Cowan DA - Sci Rep (2015)

NMDS ordination of fungal and bacterial community structure inferred from OTUs relative abundance (obtained from T-RLFPs from all water treatments and all sampling times combined).Different clusters denotes for communities originated from the riverbed (orange) and the gravel plain (brown).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4508562&req=5

f3: NMDS ordination of fungal and bacterial community structure inferred from OTUs relative abundance (obtained from T-RLFPs from all water treatments and all sampling times combined).Different clusters denotes for communities originated from the riverbed (orange) and the gravel plain (brown).
Mentions: The divergence between the two soil origins was clearer in the fungal community where the riverbed and the gravel plain clusters were clearly separated and barely overlapped compared to the bacterial community where the two clusters largely overlapped (Fig. 3). The stronger association of the fungal community structure with the soil origin suggests that desert fungal communities were either more soil-specific than bacterial communities46 or were more resistant to wetting events47.

Bottom Line: The effects of wetting event frequency and intensity on Namib Desert microbial communities from two soils with different water-regime histories were tested over 36 days.T-RFLP data showed that the different wetting events affected desert microbial community structures, but these effects were attenuated by the effects related to the long-term adaptation of both fungal and bacterial communities to soil origins (i.e. soil water regime histories).The intensity of the water pulses (i.e. the amount of water added) rather than the frequency of wetting events had greatest effect in shaping bacterial and fungal community structures.

View Article: PubMed Central - PubMed

Affiliation: Centre for Microbial Ecology and Genomics (CMEG), Genomic Research Institute, University of Pretoria, Pretoria, South Africa.

ABSTRACT
Despite the dominance of microorganisms in arid soils, the structures and functional dynamics of microbial communities in hot deserts remain largely unresolved. The effects of wetting event frequency and intensity on Namib Desert microbial communities from two soils with different water-regime histories were tested over 36 days. A total of 168 soil microcosms received wetting events mimicking fog, light rain and heavy rainfall, with a parallel "dry condition" control. T-RFLP data showed that the different wetting events affected desert microbial community structures, but these effects were attenuated by the effects related to the long-term adaptation of both fungal and bacterial communities to soil origins (i.e. soil water regime histories). The intensity of the water pulses (i.e. the amount of water added) rather than the frequency of wetting events had greatest effect in shaping bacterial and fungal community structures. In contrast to microbial diversity, microbial activities (enzyme activities) showed very little response to the wetting events and were mainly driven by soil origin. This experiment clearly demonstrates the complexity of microbial community responses to wetting events in hyperarid hot desert soil ecosystems and underlines the dynamism of their indigenous microbial communities.

No MeSH data available.