Plenary Presentations, Wednesday, June 24Room: Ballroom C/D Wednesday, 8:00 - 9:00 AM |
| 8:00-9:00AM Microbial Communities as Transducers of Ecosystem Response to Climate Change.
Dr. Mary Firestone
Introduction by Dr. Pat Megonigal The nutrient retention service of wetlands in agricultural landscapes has been widely recognized and is supported by good scientific evidence in several parts of the world. Often, the conservation or restoration of riparian forests, flow-through wetlands or pond-ditch systems is driven by the dual purpose of nutrient retention and biodiversity enhancement. Recent studies have addressed biodiversity of such wetlands at different scales (i.e. alpha, beta and gamma diversity) and have combined studies of vegetation, fauna and microbial communities. The results give guidance for the size and density of wetlands in the landscape optimal from a biodiversity perspective. Further relevant issues in this respect include critical loading rates, the role of pulsing and the overall water quality effects in the catchment. |
Room: Ballroom C/D Wednesday, 4:30-5:10 PM |
|
4:30-5:10PM Interrogating the Microbial World
Dr. James Tiedje
Introduction by Dr. Pat Megonigal The microbial world is arguably the greatest under-explored resource for biological discovery, both for basic contributions to knowledge about the diversity and strategies for life, and for harvesting that novelty for applications from medicines to biofuels (1). Evidence from 16S rRNA gene sequences, metagenomic studies, descriptions of new isolates, and from habitat, spatial and organism studies all suggest that the diversity of the microbial world is enormous. Interrogation of the microbial world by the new technologies is providing better insight into that diversity, including its functions, and should eventually allow us to manage communities and potentially capture desired members for a variety of uses. We have used comparative genomics to advance our understanding of bacterial "species" (2,3), until now a poorly understood characterization. These studies show that considerable genetic diversity resides within currently named species, and that ecology plays a role in speciation, which is not recognized in the current bacterial species definition. The recent and impending advances in sequencing technology are providing unprecedented opportunities to explore the microbial world, both via targeted genes, e.g. phylogenetically informative genes like 16S rRNA or genes of important function (biogeochemical cycles, virulence, biodegradation), via metagenomics and to understand their spatial patterns (4). We have used the former along with new high throughput analysis tools to analyze tens of thousands of members of soil and sediment communities to learn what microbial groups are selected by particular environments and where novel diversity resides. One of the discoveries of the past decade is finding that major process in the nitrogen cycle, anammox, had been completely overlooked (5). Molecular methods, augmented by stable isotope methods, have provided insight into this process although the ecology (especially in wetlands) and physiology of these currently non-culturable organisms remains to be understood. The ability of the new sequencing and other molecular technologies to obtain greater sequence depth along with spatial and temporal patterns will provide the power to unveil the microbial community at both the organism and gene level and hence more reliably predict and use their functions. 1. Tiedje, J. and T. Donohue. 2008. Microbes in the Energy Grid. Science Editorial, 320: 985. 2. Konstantinidis, K. and J.M. Tiedje. 2005. Genomic insights that advance the species definition for prokaryotes. PNAS, 102:2567-2572. 3. Konstantinidis, K.T., A. Ramette and J.M. Tiedje. 2006. The bacterial species definition in the genomic era. Phil. Trans. R. Soc. B. 361:1929-1940. 4. Ramette, A. & J.M. Tiedje. 2007. Multiscale responses of microbial life to spatial distance and environmental heterogeneity in a patchy ecosystem. PNAS 104:2761-2766. 5. Penton, C.R., A.H. Devol and J.M. Tiedje. 2006. Molecular evidence for the broad distribution of anaerobic ammonium-oxidizing bacteria in freshwater and marine sediments. Appl. Environ. Microbiol. 72:6829-6832 |