Limits...
Stochastic assembly leads to alternative communities with distinct functions in a bioreactor microbial community.

Zhou J, Liu W, Deng Y, Jiang YH, Xue K, He Z, Van Nostrand JD, Wu L, Yang Y, Wang A - MBio (2013)

Bottom Line: Neutral community modeling analysis revealed that deterministic factors also played significant roles in shaping microbial community structure in these reactors.Moreover, while microorganisms mediate many ecosystem processes, the relationship between microbial diversity and ecosystem functioning remains largely elusive.The results presented in this study represent important contributions to the understanding of the mechanisms, especially stochastic processes, involved in shaping microbial biodiversity.

View Article: PubMed Central - PubMed

Affiliation: State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing, China. jzhou@ou.edu

ABSTRACT
ABSTRACT The processes and mechanisms of community assembly and its relationships to community functioning are central issues in ecology. Both deterministic and stochastic factors play important roles in shaping community composition and structure, but the connection between community assembly and ecosystem functioning remains elusive, especially in microbial communities. Here, we used microbial electrolysis cell reactors as a model system to examine the roles of stochastic assembly in determining microbial community structure and functions. Under identical environmental conditions with the same source community, ecological drift (i.e., initial stochastic colonization) and subsequent biotic interactions created dramatically different communities with little overlap among 14 identical reactors, indicating that stochastic assembly played dominant roles in determining microbial community structure. Neutral community modeling analysis revealed that deterministic factors also played significant roles in shaping microbial community structure in these reactors. Most importantly, the newly formed communities differed substantially in community functions (e.g., H2 production), which showed strong linkages to community structure. This study is the first to demonstrate that stochastic assembly plays a dominant role in determining not only community structure but also ecosystem functions. Elucidating the links among community assembly, biodiversity, and ecosystem functioning is critical to understanding ecosystem functioning, biodiversity preservation, and ecosystem management. IMPORTANCE Microorganisms are the most diverse group of life known on earth. Although it is well documented that microbial natural biodiversity is extremely high, it is not clear why such high diversity is generated and maintained. Numerous studies have established the roles of niche-based deterministic factors (e.g., pH, temperature, and salt) in shaping microbial biodiversity, the importance of stochastic processes in generating microbial biodiversity is rarely appreciated. Moreover, while microorganisms mediate many ecosystem processes, the relationship between microbial diversity and ecosystem functioning remains largely elusive. Using a well-controlled laboratory system, this study provides empirical support for the dominant role of stochastic assembly in creating variations of microbial diversity and the first explicit evidence for the critical role of community assembly in influencing ecosystem functioning. The results presented in this study represent important contributions to the understanding of the mechanisms, especially stochastic processes, involved in shaping microbial biodiversity.

Show MeSH

Related in: MedlinePlus

Average yields of H2, CH4, and CO2 for the four reactor groups as shown in Fig. 2. The average yields and standard deviations of each gas were obtained based on individual measurements across experimental time among reactors. H2 yields were dramatically different among these reactors, whereas lesser variations were observed for CH4 and CO2.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC3585448&req=5

fig3: Average yields of H2, CH4, and CO2 for the four reactor groups as shown in Fig. 2. The average yields and standard deviations of each gas were obtained based on individual measurements across experimental time among reactors. H2 yields were dramatically different among these reactors, whereas lesser variations were observed for CH4 and CO2.

Mentions: Although stochastic assembly leads to multiple community states, it is not clear whether such community assembly processes affect community functioning. In this study, the functions of the MEC reactor communities were assessed mainly based on the production of various gases: H2, CH4, and CO2. Based on the yields of H2 and CH4, these reactors can also be divided into four groups, which are consistent with those based on community structure by DCA. Gas production varied significantly among these four groups (Fig. 3), as indicated by analysis of variance (ANOVA) (F3,10 = 50.93 and P < 0.05 for H2; F3,10 = 16.83 and P < 0.05 for CH4; and F3,10 = 7.01 and P < 0.05 for CO2). For instance, group A produced about 76 times more H2 than group D did. In addition, Mantel tests showed that there were significant correlations between the changes of gas yields and community β-diversity measured by Sorensen dissimilarity (rM = 0.394, P = 0.019) or Bray-Curtis dissimilarity (rM = 0.384, P = 0.023), indicating that the functional differences among these reactors are most likely due to the differences in community structure. Therefore, our results suggested that stochastic assembly (stochastic colonization and extinction) leads to multiple community states with distinct community functions.


Stochastic assembly leads to alternative communities with distinct functions in a bioreactor microbial community.

Zhou J, Liu W, Deng Y, Jiang YH, Xue K, He Z, Van Nostrand JD, Wu L, Yang Y, Wang A - MBio (2013)

Average yields of H2, CH4, and CO2 for the four reactor groups as shown in Fig. 2. The average yields and standard deviations of each gas were obtained based on individual measurements across experimental time among reactors. H2 yields were dramatically different among these reactors, whereas lesser variations were observed for CH4 and CO2.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3585448&req=5

fig3: Average yields of H2, CH4, and CO2 for the four reactor groups as shown in Fig. 2. The average yields and standard deviations of each gas were obtained based on individual measurements across experimental time among reactors. H2 yields were dramatically different among these reactors, whereas lesser variations were observed for CH4 and CO2.
Mentions: Although stochastic assembly leads to multiple community states, it is not clear whether such community assembly processes affect community functioning. In this study, the functions of the MEC reactor communities were assessed mainly based on the production of various gases: H2, CH4, and CO2. Based on the yields of H2 and CH4, these reactors can also be divided into four groups, which are consistent with those based on community structure by DCA. Gas production varied significantly among these four groups (Fig. 3), as indicated by analysis of variance (ANOVA) (F3,10 = 50.93 and P < 0.05 for H2; F3,10 = 16.83 and P < 0.05 for CH4; and F3,10 = 7.01 and P < 0.05 for CO2). For instance, group A produced about 76 times more H2 than group D did. In addition, Mantel tests showed that there were significant correlations between the changes of gas yields and community β-diversity measured by Sorensen dissimilarity (rM = 0.394, P = 0.019) or Bray-Curtis dissimilarity (rM = 0.384, P = 0.023), indicating that the functional differences among these reactors are most likely due to the differences in community structure. Therefore, our results suggested that stochastic assembly (stochastic colonization and extinction) leads to multiple community states with distinct community functions.

Bottom Line: Neutral community modeling analysis revealed that deterministic factors also played significant roles in shaping microbial community structure in these reactors.Moreover, while microorganisms mediate many ecosystem processes, the relationship between microbial diversity and ecosystem functioning remains largely elusive.The results presented in this study represent important contributions to the understanding of the mechanisms, especially stochastic processes, involved in shaping microbial biodiversity.

View Article: PubMed Central - PubMed

Affiliation: State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing, China. jzhou@ou.edu

ABSTRACT
ABSTRACT The processes and mechanisms of community assembly and its relationships to community functioning are central issues in ecology. Both deterministic and stochastic factors play important roles in shaping community composition and structure, but the connection between community assembly and ecosystem functioning remains elusive, especially in microbial communities. Here, we used microbial electrolysis cell reactors as a model system to examine the roles of stochastic assembly in determining microbial community structure and functions. Under identical environmental conditions with the same source community, ecological drift (i.e., initial stochastic colonization) and subsequent biotic interactions created dramatically different communities with little overlap among 14 identical reactors, indicating that stochastic assembly played dominant roles in determining microbial community structure. Neutral community modeling analysis revealed that deterministic factors also played significant roles in shaping microbial community structure in these reactors. Most importantly, the newly formed communities differed substantially in community functions (e.g., H2 production), which showed strong linkages to community structure. This study is the first to demonstrate that stochastic assembly plays a dominant role in determining not only community structure but also ecosystem functions. Elucidating the links among community assembly, biodiversity, and ecosystem functioning is critical to understanding ecosystem functioning, biodiversity preservation, and ecosystem management. IMPORTANCE Microorganisms are the most diverse group of life known on earth. Although it is well documented that microbial natural biodiversity is extremely high, it is not clear why such high diversity is generated and maintained. Numerous studies have established the roles of niche-based deterministic factors (e.g., pH, temperature, and salt) in shaping microbial biodiversity, the importance of stochastic processes in generating microbial biodiversity is rarely appreciated. Moreover, while microorganisms mediate many ecosystem processes, the relationship between microbial diversity and ecosystem functioning remains largely elusive. Using a well-controlled laboratory system, this study provides empirical support for the dominant role of stochastic assembly in creating variations of microbial diversity and the first explicit evidence for the critical role of community assembly in influencing ecosystem functioning. The results presented in this study represent important contributions to the understanding of the mechanisms, especially stochastic processes, involved in shaping microbial biodiversity.

Show MeSH
Related in: MedlinePlus