Spatial patterns in microbial communities. Franklin, R. B. Ph.D. Thesis, University of Virginia, Charlottesville, VA, 2004.
Spatial patterns in microbial communities [link]Paper  abstract   bibtex   
In this dissertation, field studies were combined with laboratory experiments to examine the local spatial distribution of microbial communities, considering a number of ecological settings and spatial scales. For the field experiments, three sites on Virginias Eastern Shore were selected: a groundwater aquifer, a salt-marsh creek bank, and an agricultural wheat field. The microbial communities inhabiting these areas were sampled at several scales (from 2.5 cm to \textgreater150 m), and compared using geostatistical techniques. Laboratory experiments were conducted as batch cultures, using sewage microbial communities, and provided a means of comparing community structure and function at very small scales (“habitat size”: 1 nl to 1 ml). In the field studies, significant spatial autocorrelation was observed, and different microbial community properties (e.g., abundance, community structure) had different distribution patterns. In some cases, multiple, nested scales of spatial organization were observed. Similar patterns were observed in the distribution of physical-chemical properties, and simple causal modeling confirmed that there was a strong relationship between habitat similarity and community similarity, in excess the common spatial pattern. A second portion of this research focused on comparing community structure/diversity with community function for different sample sizes. The results indicate that sample size is a very important consideration when analyzing community structure, but may be less important when comparing overall function. The impact of sample size on the perception of community structure and activity depended on the relative distribution of organism types within the meta-community. Differences in function could not be inferred from observed differences in structure, and this is likely due to the widespread functional redundancy in microbial systems. Functional redundancy allowed these communities to maintain their \textlessitalic\textgreater in situ\textless/italic\textgreater activity, despite the loss of many individual types of organisms from the consortium. Collectively, these results demonstrate that a researchers perception of the community-environment relationship may be greatly influenced by the scale/extent of sampling, and support the use of a spatially explicit approach in environmental microbiology. Moreover, conclusions about the organization of microbial communities, disturbance, or the roles of various limiting factors may differ at different spatial scales and depend on the level of functional redundancy present in the system.
@phdthesis{franklin_spatial_2004,
	address = {Charlottesville, VA},
	title = {Spatial patterns in microbial communities},
	url = {http://wwwlib.umi.com/dissertations/fullcit/3131425},
	abstract = {In this dissertation, field studies were combined with laboratory experiments to examine the local spatial distribution of microbial communities, considering a number of ecological settings and spatial scales. For the field experiments, three sites on Virginias Eastern Shore were selected: a groundwater aquifer, a salt-marsh creek bank, and an agricultural wheat field. The microbial communities inhabiting these areas were sampled at several scales (from 2.5 cm to {\textgreater}150 m), and compared using geostatistical techniques. Laboratory experiments were conducted as batch cultures, using sewage microbial communities, and provided a means of comparing community structure and function at very small scales (\“habitat size\”: 1 nl to 1 ml). In the field studies, significant spatial autocorrelation was observed, and different microbial community properties (e.g., abundance, community structure) had different distribution patterns. In some cases, multiple, nested scales of spatial organization were observed. Similar patterns were observed in the distribution of physical-chemical properties, and simple causal modeling confirmed that there was a strong relationship between habitat similarity and community similarity, in excess the common spatial pattern. A second portion of this research focused on comparing community structure/diversity with community function for different sample sizes. The results indicate that sample size is a very important consideration when analyzing community structure, but may be less important when comparing overall function. The impact of sample size on the perception of community structure and activity depended on the relative distribution of organism types within the meta-community. Differences in function could not be inferred from observed differences in structure, and this is likely due to the widespread functional redundancy in microbial systems. Functional redundancy allowed these communities to maintain their {\textless}italic{\textgreater} in situ{\textless}/italic{\textgreater} activity, despite the loss of many individual types of organisms from the consortium. Collectively, these results demonstrate that a researchers perception of the community-environment relationship may be greatly influenced by the scale/extent of sampling, and support the use of a spatially explicit approach in environmental microbiology. Moreover, conclusions about the organization of microbial communities, disturbance, or the roles of various limiting factors may differ at different spatial scales and depend on the level of functional redundancy present in the system.},
	school = {University of Virginia},
	author = {Franklin, Rima B.},
	year = {2004},
	keywords = {VCR}
}

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