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Full-Text Articles in Life Sciences

Collaborative Research: Toward Environmental Genomics: Can We Estimate Bacterial Diversity In The Ocean?, Daniel L. Distel Nov 2005

Collaborative Research: Toward Environmental Genomics: Can We Estimate Bacterial Diversity In The Ocean?, Daniel L. Distel

University of Maine Office of Research Administration: Grant Reports

Environmental genomics, wherein the total genomic diversity of a natural community may be sampled and analyzed in an ecological context, remains an elusive goal. This is due, at least in part, to (I) a lack of reliable estimates of total community diversity and (II) a lack of information regarding the exact phylogenetic, genomic and ecological units measured by commonly used diversity estimators. Although ribosomal RNA approaches have provided the first steps towards diversity estimation, and are widely used as a proxy for unique bacterial types in natural populations, the genomic unit a ribotype measures remains largely unexplored. It is generally …


Plant Controls Of Terrestrial Trace Gas Fluxes: Legumes, Microbes, Co And Hydrogen, Gary M. King Sep 2005

Plant Controls Of Terrestrial Trace Gas Fluxes: Legumes, Microbes, Co And Hydrogen, Gary M. King

University of Maine Office of Research Administration: Grant Reports

This research seeks to determine the role of plant-microbe interactions on the production and fate of key trace gases in the atmosphere, particularly carbon monoxide (CO) and hydrogen (H2). Recent observations have revealed that the roots of all plants produce CO, and that the roots of nitrogen-fixing plants (Fabacae, commonly legumes) produce large amounts of both CO and H2. Production of these gases provides the basis for an interaction of plant roots with soil microbes that oxidize CO and H2. Field and greenhouse studies will involve a variety of cultivated and non-cultivated legumes and other plant taxa. Experimental analyses will …


Implications Of Spatial Autocorrelation And Dispersal For The Modeling Of Species Distributions, Volker Bahn Aug 2005

Implications Of Spatial Autocorrelation And Dispersal For The Modeling Of Species Distributions, Volker Bahn

Electronic Theses and Dissertations

Modeling the geographical distributions of wildlife species is important for ecology and conservation biology. Spatial autocorrelation in species distributions poses a problem for distribution modeling because it invalidates the assumption of independence among sample locations. I explored the prevalence and causes of spatial autocorrelation in data from the Breeding Bird Survey, covering the conterminous United States, using Regression Trees, Conditional Autoregressive Regressions (CAR), and the partitioning of variance. I also constructed a simulation model to investigate dispersal as a process contributing to spatial autocorrelation, and attempted to verify the connection between dispersal and spatial autocorrelation in species' distributions in empirical …