366 research outputs found

    Soil Erosion and Surface Water Quality Impacts of Natural Gas Development in East Texas, USA

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    Due to greater demands for hydrocarbons and improvements in drilling technology, development of oil and natural gas in some regions of the United States has increased dramatically. A 1.4 ha natural gas well pad was constructed in an intermittent stream channel at the Alto Experimental Watersheds in East Texas, USA (F1), while another 1.1 ha well pad was offset about 15 m from a nearby intermittent stream (F2). V-notch weirs were constructed downstream of these well pads and stream sedimentation and water quality was measured. For the 2009 water year, about 11.76 cm, or almost 222% more runoff resulted from F1 than F2. Sediment yield was significantly greater at F1, with 13,972 kg ha−1 yr−1 versus 714 kg ha−1yr−1 at F2 on a per unit area disturbance basis for the 2009 water year. These losses were greater than was observed following forest clearcutting with best management practices (111–224 kg ha−1). Significantly greater nitrogen and phosphorus losses were measured at F1 than F2. While oil and gas development can degrade surface water quality, appropriate conservation practices like retaining streamside buffers can mitigate these impacts

    Instream Woody Debris and Riparian Forest Characteristics in the Sabine River, Texas

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    We examined instream large woody debris (LWD) dynamics on the Sabine River, TX. All wood \u3e10 cm in diameter and \u3e2 m long was measured on four river meanders (meander wavelengths) below the dam on Toledo Bend Reservoir. We determined LWD species, degree of decay, bank orientation, jam association, and stage contact. We also measured riparian vegetation characteristics on each meander. LWD volumes were significantly greater at the site immediately below Toledo Bend Dam, due to the relatively steeper channel gradient and higher rates of channel erosion. Based on mass balance estimates, between 11 and 21% of total annual recruitment came from upstream fluvial transport, and the remainder resulted from bank erosion and tree mortality. We estimated average LWD residence time to be 12–14 years. The lower Sabine River is transport-limited for sediment, and the same is true for LWD. Based on these measurements, it is unlikely that Toledo Bend Reservoir is having a significant impact on LWD dynamics at the measurement reaches due to lacustrine wood storage. Of greater concern in the study system are riparian forest degradation and invasive species spread, which may dramatically affect future LWD loadings and residence times, and thus, riverine biota

    Effect of Litter Addition on Amino Acid Content and Composition in Alpine Meadow Soil

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    Litter plays an important role in plant-soil nutrient cycling. However, the response of soil amino acid pools to litter input is unclear. Therefore, the aim of this study was to explore the effects of litter addition on the content and composition of soil amino acids in an alpine meadow soil. Soil was amended with litter of its dominant species, Kobresia graminifolia, and incubated for four weeks. Our results show that litter addition significantly increased the exchangeable amino acid content and protease activity in the soil. These results are crucial for understanding the amino acid cycling in soil

    Web-Based Spatial Decision Support System and Watershed Management with a Case Study

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    In order to maintain a proper balance between development pressure and water resources protection, and also to improve public participation, efficient tools and techniques for soil and water conservation projects are needed. This paper describes the development and application of a web-based watershed management spatial decision support system, WebWMPI. The WebWMPI uses the Watershed Management Priority Indices (WMPI) approach which is a prioritizing method for watershed management planning and it integrates land use/cover, hydrological data, soils, slope, roads, and other spatial data. The land is divided into three categories: Conservation Priority Index (CPI) land, Restoration Priority Index (RPI) land, and Stormwater Management Priority Index (SMPI) land. Within each category, spatial factors are rated based on their influence on water resources and critical areas can be identified for soil conservation, water quality protection and improvement. The WebWMPI has user-friendly client side graphical interfaces which enable the public to interactively run the server side Geographic Information System to evaluate different scenarios for watershed planning and management. The system was applied for Dry Run Creek watershed (Cedar Falls, Iowa, US) as a demonstration and it can be easily used in other watersheds to prioritize crucial areas and to increase public participation for soil and water conservation projects

    Accuracy Assessment of Perimeter and Area Calculations Using Consumer-Grade GPS Units in Southern Forests

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    Field foresters have long required a method of accurate measurement of perimeter and area during forest management activities. Perimeter and area assessments that can be derived from individual waypoints collected via global positioning system (GPS) units can be an expensive endeavor. A question of concern for practicing foresters is as the cost of GPS units increase does the accuracy of waypoints and any derived perimeter and area assessments also increase? This research evaluated whether the dynamic collection of waypoints using consumer-grade GPS units ranging from 50to50 to 700 provide a sufficient level of accuracy for the calculation of perimeter and area under three types of canopy cover: a newly established 3-year-old pine plantation, a 13-year-old pine plantation nearing first thinning, and a 40-year-old mixed pine/hardwood stand. Perimeter and area accuracy was not related to cost indicating that inexpensive GPS units provide an accurate waypoint location when used to derive perimeter and area measurements. When compared to a professional survey of each cover type, the average perimeter root mean square error (RMSE) ranged from 18.72 ft (0.41% of total perimeter) in the 40-year-old mixed pine/hardwood stand to 108.50 ft (2.43% of total perimeter) in the 13-year-old pine plantation. The average area RMSE observed ranged from 0.07 acres (0.22% of total acreage) in the 3-year-old plantation to 1.32 acres (4.67% of total acreage) in the 13-year-old pine plantation. For many forestry applications needing a perimeter and acreage assessment, these levels of accuracy should be more than sufficient

    Use of Altmetrics to Analyze ScholarWorks in Natural Resource Management

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    Digital preservation of library materials has increased the need for methods to access the documents and contents maintained in digital archives. The use of altmetrics to quantify the impact of scholarly works, including PlumX, is increasing readership by listing articles in reference services. The outreach from the digital repository ScholarWorks at Stephen F. Austin State University (SFASU) highlights the impact within the natural resources community from Digital Commons, Forest Sciences Commons; and from the Natural Products Chemistry and Pharmacognosy Commons. The use of PlumX altmetrics was examined to evaluate usage, impact, and digital audience downloads for the Arthur Temple College of Forestry and Agriculture (ATCOFA) at SFASU

    Positive Relationship between Total Antioxidant Status and Chemokines Observed in Adults

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    Objective. Human evidence is limited regarding the interaction between oxidative stress biomarkers and chemokines, especially in a population of adults without overt clinical disease. The current study aims to examine the possible relationships of antioxidant and lipid peroxidation markers with several chemokines in adults. Methods. We assessed cross-sectional associations of total antioxidant status (TAS) and two lipid peroxidation markers malondialdehyde (MDA) and thiobarbituric acid reactive substances (TBARS) with a suite of serum chemokines, including CXCL-1 (GRO-α), CXCL-8 (IL-8), CXCL-10 (IP-10), CCL-2 (MCP-1), CCL-5 (RANTES), CCL-8 (MCP-2), CCL-11 (Eotaxin-1), and CCL-17 (TARC), among 104 Chinese adults without serious preexisting clinical conditions in Beijing before 2008 Olympics. Results. TAS showed significantly positive correlations with MCP-1 (r=0.15751, P=0.0014), MCP-2 (r=0.3721, P=0.0001), Eotaxin-1 (r=0.39598, P<0.0001), and TARC (r=0.27149, P=0.0053). The positive correlations remained unchanged after controlling for age, sex, body mass index, smoking, and alcohol drinking status. No associations were found between any of the chemokines measured in this study and MDA or TBARS. Similar patterns were observed when the analyses were limited to nonsmokers. Conclusion. Total antioxidant status is positively associated with several chemokines in this adult population
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