Progress 10/01/10 to 12/31/13
Outputs
Target Audience: The target audinece for this study includes swine producers, environmental scientists, and environmental policy makers. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided? This project provided development of instrumentation skills of the project staff and undergraduate students. How have the results been disseminated to communities of interest? Data is being analyzed and will be published. What do you plan to do during the next reporting period to accomplish the goals?
Nothing Reported
Impacts
What was accomplished under these goals?
Methanogenesis and nitrous oxide reductase assessment using qPCR to measure gene abundances: The measurement of an archaeael gene, mcrA, involved in the production of the greenhouse gas, methane was attempted. In order to determine abundances, a standard needs to be developed to generate curves which can be used to measure gene copies per gram of soil. Traditional microbial methods to culture members of the archaea quite often fail, so molecular techniques have been used in order to clone a copy of the mcrA gene for use in our studies. We are in the process of verifying these clones with an outside sequence company for use in our real time quantitative PCR (qPCR) protocols. The gene nosZ encodes for the enzyme nitrous oxide reductase. This enzyme is the last step in denitrification whereby the greenhouse gas nitrous oxide is reduced to dinitrogen gas. The results from qPCR analysis are found in the Table below. In the marsh-pond-marsh system, as compared to the continuous marsh system, levels of nosZ are considerably lower, by two orders of magnitude. These levels remain somewhat consistent throughout the marsh-pond-marsh system, with a slight drop in the pond section. In comparison, in the continuous marsh system, levels of nosZ increase throughout the system. Comparison of these nosZ gene levels with environmental characteristics will need to be performed to understand the environmental selection for higher levels through the system. Table 1. nosZ gene abundances as determined by qPCR Marsh-Pond-Marsh System Inlet Marsh Pond Outlet Marsh nosZ 6.9 x 104 2.4 x 104 6.0 x 104 Continuous Marsh System Inlet Marsh Middle Marsh Outlet Marsh
Publications
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Progress 01/01/12 to 12/31/12
Outputs
OUTPUTS: Carbon dioxide and methane are potent greenhouse gases that contribute to global warming. Approximately 15 to 45 percent of global methane emissions are from wetlands and rice fields. There are several constructed wetlands used for treating different wastewaters. Carbon dioxide and methane fluxes from soils or sediments depend on the interactions of several biological and physical processes in the soil or sediments. Carbon dioxide emission from sediments is based on the decomposition of organic matter and respiration, whereas methane production is a microbiological process, which is predominantly controlled by the absence of oxygen and the amount of easily degradable organic compounds. Our research is concentrated on usage of constructed wetlands to treat lagoon swine wastewater, and to investigate the carbon dioxide and methane emissions from constructed wetlands and the bacterial communities that are responsible for such emissions. An Li-COR instrument was used to measure the carbon dioxide and gas samples were obtained to measure methane by using gas chromatography. The gas fluxes were measured for every 15 minutes for one hour. We found that spatial variation occurred in gas fluxes. Also, gas fluxes increased with increased time. Flux rates of carbon dioxide were 518, 932, 1301, and 1620 micro moles per square meter at 15, 30, 45, and 60 minutes of chamber incubation, respectively. Methane fluxes were 38.2, 80.1, 101.9, and 232.1 parts per million at 15, 30, 45, and 60 minutes, respectively. These flux results were from in-situ sediment readings. PARTICIPANTS: USDA-ARS at Florence, SC are the collaborators TARGET AUDIENCES: Nothing significant to report during this reporting period. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
In the past, our research has demonstrated that constructed wetlands can remove significant amount of suspended solids, nitrogen, and phosphorus treated with lagoon swine wastewater. However, the anaerobic swine wastewater lagoons and constructed wetlands can be a source for greenhouse gases emission. These emissions can be integrated with other sources at local or regional level, which may have impact on climate change.
Publications
- No publications reported this period
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Progress 01/01/11 to 12/31/11
Outputs
OUTPUTS: Climate change, greenhouse gases, global warming have become familiar concepts worldwide. The effects from climate change may cause sea levels rise, shrinking glaciers, thawing of permafrost, flooding and drought, and problems in crop and animal production. Greenhouse gases have increased in concentration due to the use of fossil fuels, intensive farming, animal agriculture, land use changes, and wetlands. Among agricultural practices, animal manure management, including storage, land application and treatment have significantly contributed to greenhouse gases. The main thrust of our study was to quantify the greenhouse gases emission from constructed wetlands treated with swine wastewater, and the microbial processes involved in the production of greenhouse gases such as methane and nitrous oxide. Such information will be useful to the modeling scientists, scientific community, and swine operations using such treatment systems. PARTICIPANTS: USDA-ARS at Florence, SC are the collaborators TARGET AUDIENCES: Nothing significant to report during this reporting period. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
North Carolina is the second largest swine producer in the United States and contributes to the climate change through the usage of anaerobic lagoons for swine liquid manure storage. We have scientifically demonstrated that constructed wetlands have significantly reduced nutrients concentration when treated with the swine wastewater from anaerobic lagoon. However, these constructed wetlands will also be a source for greenhouse gases emission, and may contribute to climate change at local or regional scale. The constructed wetlands were treated with the swine wastewater for the past ten years and carbon has been sequestered. The gas flux chambers were installed and gas measurements were made in summer and fall. The methane emission ranged from 0.66 to 21.8 grams per cubic meter per day and nitrous oxide emission ranged from 0.13 to 31.3 milligrams per cubic meter per day. Higher gas emissions were observed in summer months than in fall months.
Publications
- No publications reported this period
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Progress 01/01/10 to 12/31/10
Outputs
OUTPUTS: Greenhouse gases are responsible for global warming and agricultural is one of the main sources of these gases. Among agricultural practices, animal manure application on land, animal manure storage in anaerobic lagoons, and animal manure treatment through constructed wetlands will contribute to greenhouse gases. Therefore our objectives are to: quantify the gas fluxes in constructed wetlands and anaerobic lagoon treated with swine wastewater, and find microbial community responsible for the emissions of greenhouse gases from these sources. PARTICIPANTS: Nothing significant to report during this reporting period. TARGET AUDIENCES: Nothing significant to report during this reporting period. PROJECT MODIFICATIONS: Constructed wetlands treated with wastewater have potential to emit high greenhouse gases and these gas fluxes in wetlands are mediated by microbial processes. The microorganisms present and their diversity and functionality depend on environment, hydrology, and nutritional loads of wetlands. The objectives of this research are to quantify the gas fluxes in constructed wetlands receiving swine wastewater at laboratory and field scale and to find microbial communities responsible for the emission of greenhouse gases.
Impacts
North Carolina ranks second in hog production and, consequently, in swine manure production. Hog operations in North Carolina use anaerobic lagoons and spray fields to store and dispose of wastewater flushed from swine houses in a system that threatens ground and surface water quality, particularly during prolonged periods of heavy rain. Therefore constructed wetlands are being researched for their ability to reduce the nutrient concentration in swine waste. However, both lagoons and constructed wetlands emit methane and nitrous oxide into the atmosphere which contribute to global warming. For this reason, estimating emissions of these gases from swine waste can be useful in predicting its contribution to global warming. Global warming has reduced glaciers in the arctic, causing oceans to lose salinity, and is believed to be responsible for changing weather patterns that are causing droughts and floods, which are affecting the global economy and people's livelihoods and well-being. The findings from this research can be useful in modeling and predicting future global warming scenarios; predictions which will be crucial in efforts to slow the global warming process and attempts to plan ahead for the effects of global climate change on people, property and social stability.
Publications
- No publications reported this period
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