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Harvard Forest Symposium Abstract 2011

  • Title: Metagenomic study of soil microbial community composition at multiple spatial scales
  • Primary Author: William Landesman (University of Maryland Center for Environmental Science)
  • Additional Authors: David Nelson (University of Maryland Center for Environmental Science)
  • Abstract:

    Very little is known about how soil microbial communities are structured over multiple spatial scales (i.e. meters to 100’s of miles). Microbial community composition may be influenced by dispersal limitations, site characteristics or both. Several recent studies have indicated that soil microbial communities are primarily structured by soil characteristics (i.e. pH). However, the influence of soil properties on microbial community composition may be indirect, via the direct influence of soil properties on plant community composition. Plants, in turn, may influence microbial community composition via the quality and quantity of carbon inputs from litter and root exudates. The objective of this study is to assess the relative importance of plant composition and soil properties on soil microbial community composition over multiple spatial scales. During June 2010 we removed 60 soil samples from Harvard Forest as a part of a broader sampling effort across the northeastern and midwestern United States. Five samples were removed, to a depth of about 5cm, within 1.5m of four Sugar Maple, Yellow Birch and American Beech trees. A similar sampling design was used at 11 other forested locations (Fig. 1). These samples were analyzed for soil pH, percent organic matter, extractable nitrogen and soil moisture. Soil DNA was extracted from subsamples and 16S rDNA amplicons were submitted for 454 sequencing. Analysis of the 16S rDNA data will commence in mid-March 2011.





    Data will be analyzed to look at the effects of space, soil properties and tree type on soil microbial community structure. The results of the pH analysis indicate that Sugar Maple trees are associated with higher soil pH values than American Beech trees at several sites. Based on our understanding of the relationship between soil microbial community composition and soil pH, we therefore predict that Sugar Maple and American Beech trees will be associated with distinct soil microbial communities at these locations. This would mean that the influence of pH on soil microbial communities could be indirect, through the direct effect of pH on plant composition. We believe that greater insight into the relationship between plants, pH and soil microbial communities may be elucidated from locations such as Harvard Forest, where soil pH adjacent to Sugar Maple and American Beech trees were similar (Fig. 2). At these locations we predict that tree species will be associated with distinct soil microbial communities. We expect that these and other insights will improve our ability to predict variation in soil microbial communities in forested ecosystems.


  • Research Category: Biodiversity Studies
    Large Experiments and Permanent Plot Studies

  • Figures:
    • HF_ConfAbstract_Fig1.pdf
    phGraph.pdf