Biogeochemistry of Arctic and Agricultural Monoliths
Dr. Gordon Southam, Dr. Miguel Valvano, Dr. Greg Thorn, Dr. Charles Trick,
Dr. Robert Schincariol
The Biotron's unique and innovative Arctic and agricultural monoliths (i.e. natural soil cross sections of 1x1x2m) will enable our Earth Sciences and Microbiology groups to investigate the fundamental biogeochemical process associated with global climate change In the Arctic and In intensive agricultural regions in Canada such as Southwestern Ontario. This will enable the investigation of such critical environmental issues as the impact of carbon cycles upon natural greenhouse gas production and the development of controlled carbon sinks, the transfer of agriculture-related pathogens through the ecosystem, and the transfer of antibiotic resistance among soil microbes. This area of interdisciplinary research has been strengthened at Western by the addition of Dr. G. Southam, a Tier 2 Canada Research Chair shared between Earth Sciences and Biology.
Canada 's Arctic region ranks second in the world in peat deposits. These water-logged ecosystems are thought to represent one of Canada's major, natural sources for greenhouse gas emissions. The net methane flux from these ecosystems represents a delicate balance between methanogenic (microorganisms that produce CH4) and methylotrophic bacteria (bacteria which can grow on reduced carbon compounds) respectively. With global climate change, the effects of warmer temperatures and wetter and dryer weather patterns on methane flux is not known. Most discussions of global warning focus on anthropogenic gas emissions. However, these peat ecosystems will be subjected to global warming which will result in altered water levels and biological activities in these highly sensitive ecosystems. Monitoring gas flux conditions and kinetics in the Arctic monoliths by gas chromatography will enable one to assess the effect of global change on net carbon cycling from these important ecosystems.
Although agriculture represents a major component of the Canadian economy, biological and chemical run-off from the agricultural industry represents a major contributor to pollution of our rivers, lakes and ground water. Hydrological and biogeochemical cycling of inorganic and organic compounds through ecosystems is controlled by the interaction of the biosphere (e.g., bacteria, fungi, algae, plants, insects) with the chemical constituents in their environment, including soil water, nutrients and pollutants. Soil monoliths are effective in modeling many environmental factors. However, they currently stop short of replicating many fundamental biological processes such as plant growth and climate change (temperature, CO2 levels) due to the absence of climate controlled facilities of sufficient size and environmental flexibility to accommodate natural monoliths.
The Biotron will enable such research through the creation of world-class climate controlled environmental chambers for coupled hydrological and biogeochemical research in natural soil monoliths. The soil monoliths are of sufficient size that they contain all of the components of ecological interest so that ground water flow and biogeochemical processes do not require scaling. This will be accomplished by the emplacement of natural soil monoliths in a controlled environment. Such natural soil monoliths allow fluid fluxes, microbial diversity, contaminant (pesticides, pathogens, nutrients) fluxes, temperature and atmospheric conditions to be defined, controlled, and intensively monitored.
The ability to replicate our natural climatic variations within the Biotron is essential to understand many subsurface biogeochemical processes. It is hypothesized that vast areas of the country, currently under permafrost conditions, will see soil zones vastly increase in biogeochemical and microbiological activity. How will these processes evolve and what will be their impact on the biosphere? The Biotron natural monoliths of Arctic permafrost will be established to address this question and to assess the impact of climate change on the biogeochemical processes within the Arctic tundra. This will provide important data for climate change modeling and climate change policy.
A similar approach will be used to study the impact of climatic conditions on biogeochemical processes involved in agricultural monoliths with a focus on the transport and persistence of bacterial pathogens and pesticides from agricultural sources into the soil and into ground water. What elects do changes in climatic conditions such as CO2 concentrations, temperature, water and nutrient availability have on the bacterial proliferation and pathogenicity within the soil? To what extent can we detect genetic flow within the soil microbial population as estimated by the transfer of antibiotic resistance and do alterations in climatic conditions alter the flow of genetic information? This research is integrated with the research on soil microbial biodiversity (Thorn) and bacterial soil pathogens (Valvano).
This facility represents an unprecedented national and international opportunity to further experimental ecosystem research through the study of natural soil monoliths under controlled environment conditions. This facility is innovative because of its unprecedented integration of earth science, microbiology, medicine and plant biology and its scale and flexibility with respect to controlled environment conditions. This research will be a critical catalyst to bridge the gap between the laboratory and nature.
