Environmental Science & Technology Research Works
Permanent URI for this collectionhttp://hdl.handle.net/1903/1601
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Item Redox Heterogeneity Entangles Soil and Climate Interactions(MDPI, 2021-09-09) Wilmoth, Jared L.Interactions between soils and climate impact wider environmental sustainability. Soil heterogeneity intricately regulates these interactions over short spatiotemporal scales and therefore needs to be more finely examined. This paper examines how redox heterogeneity at the level of minerals, microbial cells, organic matter, and the rhizosphere entangles biogeochemical cycles in soil with climate change. Redox heterogeneity is used to develop a conceptual framework that encompasses soil microsites (anaerobic and aerobic) and cryptic biogeochemical cycling, helping to explain poorly understood processes such as methanogenesis in oxygenated soils. This framework is further shown to disentangle global carbon (C) and nitrogen (N) pathways that include CO2, CH4, and N2O. Climate-driven redox perturbations are discussed using wetlands and tropical forests as model systems. Powerful analytical methods are proposed to be combined and used more extensively to study coupled abiotic and biotic reactions that are affected by redox heterogeneity. A core view is that emerging and future research will benefit substantially from developing multifaceted analyses of redox heterogeneity over short spatiotemporal scales in soil. Taking a leap in our understanding of soil and climate interactions and their evolving influence on environmental sustainability then depends on greater collaborative efforts to comprehensively investigate redox heterogeneity spanning the domain of microscopic soil interfaces.Item Variation in Plant Community Composition and Biomass to Macro and Micronutrients and Salinity across Egypt’s Five Major Coastal Lakes(MDPI, 2022-05-19) Keshta, Amr E.; Shaltout, Kamal H.; Baldwin, Andrew H.; Sharaf El-Din, Ahmed; Eid, Ebrahem M.To better assess the relationship between excess nutrient runoff and plant species diversity in the Egyptian northern coastal lakes, the relationships between aboveground biomass, species diversity, and both micro and macronutrient concentrations in sediment, water, and plant materials were investigated. A total of 38 sampling sites were established for the five Egyptian northern lakes (8 for Bardawil, 10 for Manzala, 8 for Burullus, and 6 for each of Edku and Mariut). Sediment, water, and plant materials were collected and analyzed for both micro and macronutrients including nitrogen (N), phosphorus (P), sulfur (S), magnesium (Mg), calcium (Ca), potassium (K), iron (Fe), boron (B), sodium (Na), and aluminum (Al). Based on the Sørensen similarity index, Burullus and Mariut lakes were very similar (0.70) in their vegetation composition, while Bardawil Lake had no similarity with the rest of the lakes. In sediment, Mariut Lake had the highest total P concentrations (1.3 g kg−1), while Bardawil Lake had the lowest (0.3 g kg−1). Bardawil, a hypersaline lake, had the highest concentrations for both Na and B (9.6 and 0.1 g kg−1, respectively). Among the deltaic lakes, Mariut Lake water bodies had the lowest plant species richness. The current study indicated that the excessive agricultural and industrial nutrient runoff had a greater impact on the nutrient distribution pattern and negatively impacted plant species diversity at the Egyptian coastal lakes. An integrated management plan, including establishing more pretreatment facilities for runoff and wastewater, should be implemented to reduce the nutrient loads from the main industrial and agricultural runoff sources. Moreover, periodic monitoring and assessment for nutrient runoff reaching the lakes are necessary to help reduce eutrophication levels.Item Redox Heterogeneity Entangles Soil and Climate Interactions(MDPI, 2021-09-09) Wilmoth, Jared L.Interactions between soils and climate impact wider environmental sustainability. Soil heterogeneity intricately regulates these interactions over short spatiotemporal scales and therefore needs to be more finely examined. This paper examines how redox heterogeneity at the level of minerals, microbial cells, organic matter, and the rhizosphere entangles biogeochemical cycles in soil with climate change. Redox heterogeneity is used to develop a conceptual framework that encompasses soil microsites (anaerobic and aerobic) and cryptic biogeochemical cycling, helping to explain poorly understood processes such as methanogenesis in oxygenated soils. This framework is further shown to disentangle global carbon (C) and nitrogen (N) pathways that include CO2, CH4, and N2O. Climate-driven redox perturbations are discussed using wetlands and tropical forests as model systems. Powerful analytical methods are proposed to be combined and used more extensively to study coupled abiotic and biotic reactions that are affected by redox heterogeneity. A core view is that emerging and future research will benefit substantially from developing multifaceted analyses of redox heterogeneity over short spatiotemporal scales in soil. Taking a leap in our understanding of soil and climate interactions and their evolving influence on environmental sustainability then depends on greater collaborative efforts to comprehensively investigate redox heterogeneity spanning the domain of microscopic soil interfaces.Item AN INVESTIGATION OF THE RELATIONSHIP BETWEEN THE LEVEL OF ANTIBIOTIC RESISTANCE OF ESCHERICHIA COLI IN NONTIDAL WETLANDS AND COMMON WETLAND HEALTH FACTORS(2008-05-25) Agarwal, Neil; Ahearn, Sean; Dudziak, Erik; Khan, Sehba; Marcin, Daniel; Shofnos, Matthew; Skoda, Emily; Venkatachari, Padmasini; Vocke, Robert; Tilley, DavidThis report investigated the prevalence of antibiotic resistance among Escherichia coli in the water of 13 non-tidal mitigation wetlands in Maryland, and its relation to land use and wetland health. At each site, land use, surface and sub-surface water samples, soil samples, and vegetation cover were collected. From the water samples, individual colonies of E. coli were isolated and tested, using the disc diffusion method, for resistance to the antibiotics ampicillin, ciprofloxacin, erythromycin, sulfisoxazole, and tetracycline. According to soils, vegetation and water quality improvement criteria the wetlands function like healthy wetlands. The wetlands' E. coli exhibit resistance to all of the antibiotics tested, except for ciprofloxacin. There were statistically significant relationships found between land use and antibiotic resistance, vegetation, soil and water chemistry. Surprisingly, E. coli in wetlands with smaller stocks of carbon and nitrogen in their soil exhibited more resistance to tetracycline, possibly indicating that soil quality plays an important role in fostering or fighting antibiotic resistance. The work demonstrates that antibiotic resistance is present in Maryland's wetlands, but that its spread could be subdued by healthy wetlands.