Environmental Science & Technology
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Item Mosquitoes Associated with Ditch-Plugged and Control Tidal Salt Marshes on the Delmarva Peninsula(MDPI, 2011-07-25) Leisnham, Paul T.; Sandoval-Mohapatra, SarahA study was conducted during the summer of 2009 (from July to September) to characterize mosquito communities among different habitats in five historically ditched tidal salt marshes and three adjacent wooded areas in the E.A. Vaughn Wetland Management Area on the Maryland Delmarva Peninsula, USA. Study marshes are characteristic of Atlantic coastal salt marshes that had undergone grid ditching from the 1930s to 1950s. In the autumn of 2008 (October and November) ditches were plugged near their outlets in two (‘experimental’) marshes with the aim to restore their natural tidal hydrology. The three other marshes were not plugged. Marshes were sampled from July to September in 2009 by using standard dip count method. A total of 2,457 mosquito larvae representing six species were collected on 15.4% (86/557) of all sample occasions and 399 adults representing four mosquito species were collected from landing counts. Aedes sollicitans, Anopheles bradleyi and Culex salinarius were the most common species collected in larval habitats, and Ae. sollicitans was the most common adult collected. Wooded habitats had more total mosquitoes, were also more frequently occupied by mosquitoes and had higher densities of mosquitoes than marsh habitats. Almost all larvae collected from marshes were from one experimental and one control site. The majority of larvae at the control site were Ae. sollicitans in marsh pannes while Cx. salinarius, An. bradleyi, Ae. cantator, and Ae. sollicitans were collected in high numbers from ditches at the experimental site. We found a difference in the proportion of marsh pannes occupied by Ae. sollicitans but not total mosquitoes sampled 4–5 days after spring tide events than on other occasions. Salinity measures of 42 larval habitats showed lower median salinity in mosquito-occupied habitats (11.5 ppt) than unoccupied habitats (20.1 ppt), and in habitats in wooded areas followed by ditches and pannes in marsh areas. The results of this study suggest that wooded areas adjacent to salt marshes may be a substantial source of biting adult mosquitoes usually associated with salt marsh habitats and that ditch plugging may alter the productivity of mosquitoes on some marshes. We recommend future studies consider mosquito productivity from habitats surrounding salt marshes, and if assessments of marsh alterations are a goal, compare multiple experimental and control areas before and after treatments to determine if alterations have a consistent impact on regional mosquito production.Item The White Mountain Recreational Enterprise: Bio-Political Foundations for White Mountain Apache Natural Resource Control, 1945–1960(MDPI, 2016-07-15) Tomblin, David C.Among American Indian nations, the White Mountain Apache Tribe has been at the forefront of a struggle to control natural resource management within reservation boundaries. In 1952, they developed the first comprehensive tribal natural resource management program, the White Mountain Recreational Enterprise (WMRE), which became a cornerstone for fighting legal battles over the tribe’s right to manage cultural and natural resources on the reservation for the benefit of the tribal community rather than outside interests. This article examines how White Mountain Apaches used the WMRE, while embracing both Euro-American and Apache traditions, as an institutional foundation for resistance and exchange with Euro-American society so as to reassert control over tribal eco-cultural resources in east-central Arizona.Item Post-Deepwater Horizon Oil Spill Monitoring of Louisiana Salt Marshes Using Landsat Imagery(MDPI, 2017-06-01) Mo, Yu; Kearney, Michael S.; Riter, J. C. AlexisThe Deepwater Horizon oil spill, the second largest marine oil spill in history, contaminated over a thousand kilometers of coastline in the Louisiana salt marshes and seriously threatened this valuable ecosystem. Measuring the impacts of the oil spill over the large and complex coast calls for the application of remote sensing techniques. This study develops a method for post-Deepwater Horizon oil spill monitoring of the damaged marsh vegetation using Landsat imagery. This study utilizes 10 years of Landsat data, from 2005 to 2014, to examine the longevity of the oil spill’s impacts on the marsh vegetation. AVIRIS data collected between 2010 and 2012 are used to validate the Landsat results. Landsat imagery documents the significant effect of oiling on the Normalized Difference Vegetation Index (NDVI) of the marsh vegetation in 2010 and 2011 (p < 0.01 in both cases). These results are corroborated by the AVIRIS data, which recorded the most severe impact in May 2011 followed by progressive recovery in October 2011 and October 2012. The Landsat imagery, combined with relevant environmental information and appropriate statistical tools, provides a robust and low-cost method for long-term post-oil spill monitoring of the marshes, revealing that the major aboveground impacts (at 30 m scale) of the Deepwater Horizon oil spill on Louisiana salt marshes lasted for two years. The method presented is applicable for other hazardous events whenever pre-event referencing and long-term post-event monitoring are desired, thereby offering an effective and economical tool for disaster management.Item Bioethical Considerations of Advancing the Application of Marine Biotechnology and Aquaculture(MDPI, 2017-06-24) Harrell, Reginal M.Normative ethical considerations of growth of the marine biotechnology and aquaculture disciplines in biopharming, food production, and marine products commercialization from a bioethical perspective have been limited. This paucity of information begs the question of what constitutes a bioethical approach (i.e., respect for individuals or autonomy; beneficence, nonmaleficence, and justice) to marine biotechnology and aquaculture, and whether it is one that is appropriate for consideration. Currently, thoughtful discussion on the bioethical implications of use, development, and commercialization of marine organisms or their products, as well as potential environmental effects, defaults to human biomedicine as a model. One must question the validity of using human bioethical principlism moral norms for appropriating a responsible marine biotechnology and aquaculture ethic. When considering potential impacts within these disciplines, deference must be given to differing value systems in order to find common ground to advance knowledge and avoid emotive impasses that can hinder the science and its application. The import of bioethical considerations when conducting research and/or production is discussed. This discussion is directed toward applying bioethical principles toward technology used for food, biomedical development (e.g., biopharming), or as model species for advancement of knowledge for human diseases.Item Utilization of the Maryland Environmental Justice Screening Tool: A Bladensburg, Maryland Case Study(MDPI, 2019-01-26) Driver, Aubree; Mehdizadeh, Crystal; Bara-Garcia, Samuel; Bodenreider, Coline; Lewis, Jessica; Wilson, SacobyMaryland residents’ knowledge of environmental hazards and their health effects is limited, partly due to the absence of tools to map and visualize distribution of risk factors across sociodemographic groups. This study discusses the development of the Maryland EJSCREEN (MD EJSCREEN) tool by the National Center for Smart Growth in partnership with faculty at the University of Maryland School of Public Health. The tool assesses environmental justice risks similarly to the U.S. Environmental Protection Agency’s (USEPA) EJSCREEN tool and California’s tool, CalEnviroScreen 3.0. We discuss the architecture and functionality of the tool, indicators of importance, and how it compares to USEPA’s EJSCREEN and CalEnviroScreen. We demonstrate the use of MD EJSCREEN through a case study on Bladensburg, Maryland, a town in Prince George’s County (PG) with several environmental justice concerns including air pollution from traffic and a concrete plant. Comparison reveals that environmental and demographic indicators in MD EJSCREEN most closely resemble those in EPA EJSCREEN, while the scoring is most similar to CalEnviroScreen. Case study results show that Bladensburg has a Prince George’s environmental justice score of 0.99, and that National Air Toxics Assessment (NATA) air toxics cancer risk is concentrated in communities of color.Item Urbanization Altered Bacterial and Archaeal Composition in Tidal Freshwater Wetlands Near Washington DC, USA, and Buenos Aires, Argentina(MDPI, 2019-03-06) Gonzalez Mateu, Martina; Park, Cedric Evan; McAskill, Cullen Patrick; Baldwin, Andrew H.; Yarwood, Stephanie A.Urban expansion causes coastal wetland loss, and environmental stressors associated with development can lead to wetland degradation and loss of ecosystem services. This study investigated the effect of urbanization on prokaryotic community composition in tidal freshwater wetlands. Sites in an urban, suburban, and rural setting were located near Buenos Aires, Argentina, and Washington D.C., USA. We sampled soil associated with two pairs of functionally similar plant species, and used Illumina sequencing of the 16S rRNA gene to examine changes in prokaryotic communities. Urban stressors included raw sewage inputs, nutrient pollution, and polycyclic aromatic hydrocarbons. Prokaryotic communities changed along the gradient (nested PerMANOVA, Buenos Aires: p = 0.005; Washington D.C.: p = 0.001), but did not differ between plant species within sites. Indicator taxa included Methanobacteria in rural sites, and nitrifying bacteria in urban sites, and we observed a decrease in methanogens and an increase in ammonia-oxidizers from rural to urban sites. Functional profiles in the Buenos Aires communities showed higher abundance of pathways related to nitrification and xenobiotic degradation in the urban site. These results suggest that changes in prokaryotic taxa across the gradient were due to surrounding stressors, and communities in urban and rural wetlands are likely carrying out different functions.Item Effects of Detritus on the Mosquito Culex pipiens: Phragmites and Schedonorus (Festuca) Invasion Affect Population Performance(MDPI, 2019-10-25) Leisnham, Paul T.; Scott, Brandon; Baldwin, Andrew H.; LaDeau, Shannon L.Species interactions that influence the performance of the exotic mosquito Culex pipiens can have important effects on the transmission risk of West Nile virus (WNV). Invasive plants that alter the vegetation communities of ephemeral ground pools may facilitate or resist the spread of C. pipiens (L.) by altering allochthonous inputs of detritus in those pools. To test this hypothesis, we combined field surveys of roadside stormwater ditches with a laboratory microcosm experiment to examine relationships between C. pipiens performance and water quality in systems containing detritus from invasive Phragmites australis (Cav.) Trin. Ex Steud., introduced Schedonorus arundinaceus (Schreb.) Dumort., or native Juncus effusus L. or Typha latifolia L. In ditches, C. pipiens abundance was unrelated to detritus species but female C. pipiens were significantly larger from ditches with S. arundinaceus and smaller with J. effusus. Larger and smaller C. pipiens were also produced in microcosms provisioned with S. arundinaceus and J. effusus, respectively, yet the per capita rate of population of change did not vary. Larger females from habitats with S. arundinaceus were likely caused by faster decay rates of S. arundinaceus and resultant increases in microbial food, but lower survival as a result of fouling and higher tannin-lignin concentrations resulted in little changes to overall population performance. Larger female mosquitoes have been shown to have greater potential for transmitting arboviruses. Our findings suggest that changed community-level interactions from plant invasions in urban ephemeral ground pools can affect the fitness of C. pipiens and possibly increase WNV risk.Item Methane and Hydrogen Sulfide Production from Co-Digestion of Gummy Waste with a Food Waste, Grease Waste, and Dairy Manure Mixture(MDPI, 2019-11-23) Lansing, Stephanie; Choudhury, AbhinavCo-digestion of dairy manure with waste organic substrates has been shown to increase the methane (CH4) yield of farm-scale anaerobic digestion (AD). A gummy vitamin waste (GVW) product was evaluated as an AD co-digestion substrate using batch AD testing. The GVW product was added at four inclusion levels (0%, 5%, 9%, and 23% on a wet mass basis) to a co-digestion substrate mixture of dairy manure (DM), food-waste (FW), and grease-waste (GW) and compared to mono-digestion of the GVW, DM, FW, and GW substrates. All GVW co-digestion treatments significantly increased CH4 yield by 126–151% (336–374 mL CH4/g volatile solids (VS)) compared to DM-only treatment (149 mL CH4/g VS). The GVW co-digestion treatments also significantly decreased the hydrogen sulfide (H2S) content in the biogas by 66–83% (35.1–71.9 mL H2S/kg VS) compared to DM-only (212 mL H2S/kg VS) due to the low sulfur (S) content in GVW waste. The study showed that GVW is a potentially valuable co-digestion substrate for dairy manure. The high density of VS and low moisture and S content of GVW resulted in higher CH4 yields and lower H2S concentrations, which could be economically beneficial for dairy farmers.Item Evaluation of Hydrogen Sulfide Scrubbing Systems for Anaerobic Digesters on Two U.S. Dairy Farms(MDPI, 2019-12-04) Choudhury, Abhinav; Shelford, Timothy; Felton, Gary; Gooch, Curt; Lansing, StephanieHydrogen sulfide (H2S) is a corrosive trace gas present in biogas produced from anaerobic digestion systems that should be removed to reduce engine-generator set maintenance costs. This study was conducted to provide a more complete understanding of two H2S scrubbers in terms of efficiency, operational and maintenance parameters, capital and operational costs, and the effect of scrubber management on sustained H2S reduction potential. For this work, biogas H2S, CO2, O2, and CH4 concentrations were quantified for two existing H2S scrubbing systems (iron-oxide scrubber, and biological oxidation using air injection) located on two rural dairy farms. In the micro-aerated digester, the variability in biogas H2S concentration (average: 1938 ± 65 ppm) correlated with the O2 concentration (average: 0.030 ± 0.004%). For the iron-oxide scrubber, there was no significant difference in the H2S concentrations in the pre-scrubbed (450 ± 42 ppm) and post-scrubbed (430 ± 41 ppm) biogas due to the use of scrap iron and steel wool instead of proprietary iron oxide-based adsorbents often used for biogas desulfurization. Even though the capital and operating costs for the two scrubbing systems were low (<$1500/year), the lack of dedicated operators led to inefficient performance for the two scrubbing systems.Item Soils Developed in Freshwater Marl Sediments in The Hagerstown (Great) Limestone Valley(1993) Shaw, Joey N.; Rabenhorst, Martin C.; Agronomy; Digital Repository at the University of Maryland; University of Maryland (College Park, MD)Certain calcareous soils occupying alluvial landscape positions in the Hagerstown (Great) limestone valley of western Maryland have developed from highly calcareous ( 60-100g/100g) marl sediments of Holocene age which range in depth from .5m to over 8m. These marlderived soils have a high pH ( 7. 5-8. 5) , low bulk density, and high porosity (0.5 to 0.6). The carbonate in the marl was developed from inorganic and biogenic processes. The marl was formed in now extinct ponds which had inundated alluvial landscape positions during parts of the Holocene period. Certain algae capable of accumulating carbonate internally and externally developed the majority of the marl. Pedogenic processes have transformed the marl sediments into highly calcareous Mollisols. The presence of buried surface horizons and coarse (> fine sand) carbonate forms render classification of these soils problematic. The coarse carbonate forms were mainly biogenic deposits, but these carbonates have been altered sufficiently by coating with pedogenic carbonate to identify calcic horizons. The drainage class is difficult to interpret as a result of the gleyed appearance of the marl sediments (chroma <3) and the high pH of these soils which inhibits Fe oxide reduction. Most of the marl-derived soils (70%) are better drained than the previous classification indicates. These soils have been mapped in the Great Valley in units named for the warners series (fine-silty, carbonatic, mesic Fluvaquentic Haplaquolls) and the Massenet ta series (fine-loamy, carbonatic, mesic, Fluvaquentic Hapludolls). However, proper classification may place these soils in the Typic Calciudolls subgroup. Some soils originally mapped in the very poorly drained Dunning units are very poorly drained marl-derived soils.