scholarly journals The role of ecosystem engineers in shaping the diversity and function of arid soil bacterial communities

SOIL ◽  
2021 ◽  
Vol 7 (2) ◽  
pp. 611-637
Author(s):  
Capucine Baubin ◽  
Arielle M. Farrell ◽  
Adam Št'ovíček ◽  
Lusine Ghazaryan ◽  
Itamar Giladi ◽  
...  

Abstract. Ecosystem engineers (EEs) are present in every environment and are known to strongly influence ecological processes and thus shape the distribution of species and resources. In this study, we assessed the direct and indirect effect of two EEs (perennial shrubs and ant nests), individually and combined, on the composition and function of arid soil bacterial communities. To that end, topsoil samples were collected in the Negev desert highlands during the dry season from four patch types: (1) barren soil; (2) under shrubs; (3) near ant nests; or (4) near ant nests situated under shrubs. The bacterial community composition and potential functionality were evaluated in the soil samples (14 replicates per patch type) using 16S rRNA gene amplicon sequencing together with physico-chemical measures of the soil. We have found that the EEs affected the community composition differently. Barren patches supported a soil microbiome, dominated by Rubrobacter and Proteobacteria, while in EE patches Deinococcus-Thermus dominated. The presence of the EEs similarly enhanced the abundance of phototrophic, nitrogen cycle, and stress-related genes. In addition, the soil characteristics were altered only when both EEs were combined. Our results suggest that arid landscapes foster unique communities selected by patches created by each EE(s), solo or in combination. Although the communities' composition differs, they support similar potential functions that may have a role in surviving the harsh arid conditions. The combined effect of the EEs on soil microbial communities is a good example of the hard-to-predict non-additive features of arid ecosystems that merit further research.

2021 ◽  
Author(s):  
Capucine Baubin ◽  
Arielle M. Farrell ◽  
Adam Šťovíček ◽  
Lusine Ghazaryan ◽  
Itamar Giladi ◽  
...  

Abstract. Ecosystem engineers (EEs) are present in every environment and are known to strongly influence ecological processes and thus shape the distribution of species and resources. In this study, we assessed the direct and indirect effect of two EEs (perennial shrubs and ant nests), individually and combined, on the composition and function of arid soil bacterial communities. To that end, topsoil samples were collected in the Negev Desert Highlands during the dry season from four patch types: (1) barren soil; (2) under shrubs; (3) near ant nests; or (4) near ant nests situated under shrubs. The bacterial community composition and potential functionality were evaluated in the soil samples (fourteen replicates per patch type) using 16S rRNA gene amplicon sequencing, together with physico-chemical measures of the soil. We have found that the EEs differently affected the community composition. Barren patches supported a soil microbiome, dominated by Rubrobacter and Proteobacteria, while in EE patches Deinococcus-Thermus dominated. The presence of the EEs similarly enhanced the abundance of phototrophic, nitrogen cycle and stress- related genes. In addition, the soil characteristics were altered only when both EEs were combined. Our results suggest that arid landscapes foster unique bacterial communities selected by patches created by each EE(s), solo or in combination. Although, the communities’ composition differs, they support similar potential functions that may have a role in surviving harsh arid conditions. The combined effect of the EEs on soil microbial communities is a good example of hard to predict non-additive features of arid ecosystems that, therefore, merit further research.


2020 ◽  
Author(s):  
Capucine Baubin ◽  
Arielle M. Farrell ◽  
Adam Šťovíček ◽  
Lusine Ghazaryan ◽  
Itamar Giladi ◽  
...  

ABSTRACTEcosystem engineers (EEs) are present in every environment and are known to strongly influence ecological processes and thus shape the distribution of species and resources. In this study, we assessed the direct and indirect effect of two EEs (perennial shrubs and ant nests), individually and combined, on the composition and function of arid soil bacterial communities. To that end, top soil samples were collected in the Negev Desert Highlands during the dry season from four patch types: (1) barren soil; (2) under shrubs; (3) near ant nests; or (4) near ant nests situated under shrubs. The bacterial composition was evaluated in the soil samples (fourteen replicates per patch type) using 16S rRNA gene amplicon sequencing, together with physico-chemical measures of the soil, and the potential functions of the community. We have found that the EEs differently affected the community composition. Indeed, barren patches supported a soil microbiome, dominated by Rubrobacter and Proteobacteria, while in EE patches the Deinococcus-Thermus phylum was dominating. The presence of the EEs similarly enhanced the abundance of phototrophic, nitrogen cycle and stress- related genes. In addition, only when both EEs were combined, were the soil characteristics altered. Our results imply that arid landscapes foster unique communities selected by each EE(s), solo or in combination, yet these communities have similar potential biological traits to persist under the harsh arid conditions. Environments with multiple EEs are complicated to study due to the possibility of non-additive effects of EEs and thus further research should be done.IMPORTANCEEcosystem engineers are organisms that can create, modify, or maintain their habitat. They are present in various environments but are particularly conspicuous in desert ecosystems, where their presence is tightly linked to vital resources like water or nutrients. Despite their key role in structuring and controlling desert ecosystems, joint engineering, and their effect on soil function, are unknown. Our study explores the contributions of key ecosystem engineers to the diversity and function of their soil microbiome allowing better understanding of their role in shaping habitats and engineering their activity


2019 ◽  
Author(s):  
Myrto Tsiknia ◽  
Stilianos Fodelianakis ◽  
Nikolaos P. Nikolaidis ◽  
Nikolaos V. Paranychianakis

AbstractThere is a renewed interest in recent years on the ecological processes (stochastic vs selective) driving the assembly of microbial communities. Such information could potentially improve our understanding on ecosystem functioning and resilience to disturbances, ecosystem response to environmental shifts, and adoption of sustainable soil management practices. Herein, employing a suite of existing methodologies, we show that stochastic processes have an important role on the assembly of soil bacterial communities at a Mediterranean watershed. Moreover, we document that the relative contribution of assembly processes varies over the years. The observed intensification of stochastic processes was accompanied by a decrease in the contribution of variable selection in favor of homogeneous selection and dispersal and this trend was only marginally affected by land use (natural vs agricultural lands) or soil depth. Our study also revealed a high inter-annual turnover of soil microbial communities that was likely stimulated by the weak environmental selection and the prevailing environmental conditions (drying-wetting cycles) in Mediterranean landscapes, implying potential impacts on ecosystem functioning and our ability to predict soil response to environmental shifts. Using nitrogen mineralization rate (NMR) as a representative function we document highly variable NMR over the sampling years, land uses and soil depths and lack of significant associations with the monitored environmental variables and individual taxa. In summary, our study provides novel insights on the organization and functioning of microbial communities at Mediterranean ecosystems and sets directions towards a more advanced understanding of the relationships among environmental factors, microbial community structure, and ecosystem functioning that could contribute to sustainable management of these severely degraded ecosystems.


2020 ◽  
Vol 96 (7) ◽  
Author(s):  
Ana Novoa ◽  
Jan-Hendrik Keet ◽  
Yaiza Lechuga-Lago ◽  
Petr Pyšek ◽  
Johannes J Le Roux

ABSTRACT Coastal dunes are ecosystems of high conservation value that are strongly impacted by human disturbances and biological invasions in many parts of the world. Here, we assessed how urbanization and Carpobrotus edulis invasion affect soil bacterial communities on the north-western coast of Spain, by comparing the diversity, structure and composition of soil bacterial communities in invaded and uninvaded soils from urban and natural coastal dune areas. Our results suggest that coastal dune bacterial communities contain large numbers of rare taxa, mainly belonging to the phyla Actinobacteria and Proteobacteria. We found that the presence of the invasive C. edulis increased the diversity of soil bacteria and changed community composition, while urbanization only influenced bacterial community composition. Furthermore, the effects of invasion on community composition were conditional on urbanization. These results were contrary to predictions, as both C. edulis invasion and urbanization have been shown to affect soil abiotic conditions of the studied coastal dunes in a similar manner, and therefore were expected to have similar effects on soil bacterial communities. Our results suggest that other factors (e.g. pollution) might be influencing the impact of urbanization on soil bacterial communities, preventing an increase in the diversity of soil bacteria in urban areas.


Agronomy ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 1526
Author(s):  
Xiaoqin Yang ◽  
Yang Wang ◽  
Luying Sun ◽  
Xiaoning Qi ◽  
Fengbin Song ◽  
...  

Conservative agricultural practices have been adopted to improve soil quality and maintain crop productivity. An efficient intercropping of maize with mushroom has been developed in Northeast China. The objective of this study was to evaluate and compare the effects of planting patterns on the diversity and structure of the soil bacterial communities at a 0–20 cm depth in the black soil zone of Northeast China. The experiment consisted of monoculture of maize and mushroom, and intercropping in a split-plot arrangement. The characteristics of soil microbial communities were performed by 16S rRNA gene amplicom sequencing. The results showed that intercropping increased soil bacterial richness and diversity compared with maize monoculture. The relative abundances of Acidobacteria, Chloroflexi, Saccharibacteria and Planctomycetes were significantly higher, whereas Proteobacteria and Firmicutes were lower in intercropping than maize monoculture. Redundancy analysis suggested that pH, NO3−-N and NH4+-N contents had a notable effect on the structure of the bacterial communities. Moreover, intercropping significantly increased the relative abundance of carbohydrate metabolism pathway functional groups. Overall, these findings demonstrated that intercropping of maize with mushroom strongly impacts the physical and chemical properties of soil as well as the diversity and structure of the soil bacterial communities, suggesting this is a sustainable agricultural management practice in Northeast China.


Agronomy ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 14 ◽  
Author(s):  
Yadong Yang ◽  
Peixin Wang ◽  
Zhaohai Zeng

Fertilization plays important roles in improving soil fertility and in increasing crop yield. Soil microbial communities are sensitive indicators of soil quality and health, which could be affected by fertilization strategy. However, our knowledge on how organic–inorganic fertilizers application affects soil bacterial communities remains largely poorly understood. In this study, we investigated the long-term effects of different organic–inorganic fertilization strategies: without fertilizer (CK), fertilizers NPK (CF), fertilizers NPK, plus 30% organic manure (CFM1), and fertilizers NPK plus 60% organic manure (CFM2) on soil bacterial communities in paddy fields. Results showed that the bacterial 16S ribosomal DNA (rDNA) gene abundances in treatments CF, CFM1, and CFM2 were 1.44, 1.54, and 1.28 times higher than that in CK and the ACE index in treatment CFM1 was 9.0% greater than that in treatment CFM2, respectively. Fertilization strategy significantly changed the relative abundance of Nitrospirae, Gemmatimonadetes, and unclassified bacteria at the phylum level and bacteria belonging to order Nitrospira, candidate bacterium SBR2076, unclassified bacteria, Syntrophobacterales, and Solibacterales at the order level, respectively. High organic–inorganic fertilizer application rates inhibited the growth of Nitrospirae by 20–35%, and stimulated the growth of Gemmatimonadetes by 14–77%, relative to the rest of the treatments, respectively. Hierarchical cluster and principal coordinate analysis (PCoA) showed that the fertilization strategy affected the bacterial community structures, and the organic–inorganic fertilized treatments possessed similar bacterial community structures. Furthermore, soil pH, total nitrogen (TN), and soil organic carbon (SOC) were the main driving factors altering the bacterial communities. Our results suggested that combined organic–inorganic fertilizers application increased soil nutrient contents and bacterial abundances, and this could be an optimized fertilization strategy in regulating soil bacterial communities for rice production.


2017 ◽  
Vol 84 (4) ◽  
Author(s):  
Sammy Frenk ◽  
Yitzhak Hadar ◽  
Dror Minz

ABSTRACTAnthropogenic activities alter the structure and function of a bacterial community. Furthermore, bacterial communities structured by the conditions the anthropogenic activities present may consequently reduce their stability in response to an unpredicted acute disturbance. The present mesocosm-scale study exposed soil bacterial communities to different irrigation water types, including freshwater, fertilized freshwater, treated wastewater, and artificial wastewater, and evaluated their response to a disturbance caused by heat. These effectors may be considered deterministic and stochastic forces common in agricultural operations of arid and semiarid regions. Bacterial communities under conditions of high mineral and organic carbon availability (artificial wastewater) differed from the native bacterial community and showed a proteobacterial dominance. These bacterial communities had a lower resistance to the heat treatment disturbance than soils under conditions of low resource availability (high-quality treated wastewater or freshwater). The latter soil bacterial communities showed a higher abundance of operational taxonomic units (OTUs) classified asBacilli. These results were elucidated by soil under conditions of high resource availability, which lost higher degrees of functional potential and had a greater bacterial community composition change. However, the functional resilience, after the disturbance ended, was higher under a condition of high resource availability despite the bacterial community composition shift and the decrease in species richness. The functional resilience was directly connected to the high growth rates of certainBacteroidetesand proteobacterial groups. A high stability was found in samples that supported the coexistence of both resistant OTUs and fast-growing OTUs.IMPORTANCEThis report presents the results of a study employing a hypothesis-based experimental approach to reveal the forces involved in determining the stability of a soil bacterial community to disturbance. The resultant postdisturbance bacterial community composition dynamics and functionality were analyzed. The paper demonstrates the relatedness of community structure and stability under cultivation conditions prevalent in an arid area under irrigation with water of different qualities. The use of common agricultural practices to demonstrate these features has not been described before. The combination of a fundamental theoretical issue in ecology with common and concerning disturbances caused by agricultural practice makes this study unique. Furthermore, the results of the present study have applicable importance regarding soil conservation, as it enables a better characterization and monitoring of stressed soil bacterial communities and possible intervention to reduce the stress. It will also be of valued interest in coming years, as fresh water scarcity and the use of alternative water sources are expected to rise globally.


Agronomy ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 878 ◽  
Author(s):  
Zoltán Mayer ◽  
Zita Sasvári ◽  
Viktor Szentpéteri ◽  
Beatrix Pethőné Rétháti ◽  
Balázs Vajna ◽  
...  

Soil microbial communities are involved in the maintenance of productivity and health of agricultural systems; therefore an adequate understanding of soil biodiversity plays a key role in ensuring sustainable use of soil. In the present study, we evaluated the influence of different cropping systems on the biodiversity of the soil bacterial communities, based on a 54-year field experiment established in Martonvásár, Hungary. Terminal restriction fragment length polymorphism (T-RFLP) fingerprinting technique was used to assess soil bacterial diversity and community structure in maize monoculture and three different crop rotations (maize–alfalfa, maize–wheat and the maize–barley–peas–wheat Norfolk type). No differences in richness and diversity were detected between maize monoculture and crop rotations except for the most intense rotation system (Norfolk-type). Although the principal component analysis did not reveal a clear separation between maize monoculture and the other rotation systems, the pairwise tests of analysis of similarity (ANOSIM) revealed that there are significant differences in the composition of bacterial communities between the maize monoculture and maize–alfalfa rotation as well as between wheat–maize and Norfolk-type rotation.


Diversity ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 217 ◽  
Author(s):  
Adenike Eunice Amoo ◽  
Olubukola Oluranti Babalola

Soil microbial communities are an important part of ecosystems that possess the capability to improve ecosystem services; however, several aspects of the ecology of forest soil bacterial communities are still unknown. Here, we investigated the impact of land-use change on soil bacterial communities and the soil characteristics. High-throughput sequencing was used to ascertain the bacterial diversity and canonical correspondence analysis was used to determine relationships between the bacterial communities and environmental variables. Our results show spatial heterogeneity in the distribution of the microbial communities and significant relationships between the microbes and soil characteristics (axis 1 of the canonical correspondence analysis (CCA) plot explained 64.55% of the total variance while axis 2 described 24.49%). Knowledge of this is essential as it has direct consequences for the functioning of the soil ecosystem.


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