Since the 1970s, a growing body of research has suggested that bacteria play an active role in precipitation. These bacteria are capable of catalyzing the formation of ice at relatively warm temperatures utilizing a specific protein family which aids in the binding of water molecules. However, the overall biodiversity, concentration, and relationship of ice nucleation active (ice+) bacteria with air mass trajectories and precipitation chemistry is not well studied. Precipitation events were collected over 15 months in Blacksburg, VA and ice+ bacteria were isolated from these samples. From these samples, 33,134 total isolates were screened for ice nucleation activity (INA) at -8 °C. A total of 593 of these isolated positively confirmed for INA at the same temperature in subsequent tests. The precipitation events had a mean concentration of 384±147 colony forming units per liter. While the majority of confirmed ice+ bacteria belonged to the gammaproteobacteria, a well-studied class of bacteria, including ice+ species of Pseudomonas, Pantoea, and Xanthomonas, two isolates were identified as Lysinibacillus, a Gram-positive member of the Firmicute phylum. These two isolates represent the first confirmed non-gammaproteobacteria with INA. After further characterization, the two isolates of Lysinibacillus did not appear to use a protein to freeze water. Instead, the Lysinibacillus isolates used a secreted, nanometer-sized molecule that is heat, lysozyme, and proteinase resistant. In an attempt to identify the mechanism responsible for this activity, species type strains were tested for INA and UV mutants were generated to knock out the ice+ phenotype. Based on these results, only members of the species L. parviboronicapiens exhibit INA and the genes responsible for the activity may lie within a type-1 polyketide synthase/non-ribosomal peptide synthase gene cluster. This gene cluster is absent from the genomes of all non-ice+ strains of Lysinibacillus, and contains mutations in five of the nine ice nucleation inactive mutants generated from the rain isolated strain. To better understand the phylogenetic relationship among ice+ Lysinibacillus, a comprehensive reference guide was compiled to provide the most up-to-date information regarding the genus and each of its species. This reference will be available to other researchers investigating Lysinibacillus species or other closely related genera. / PHD / It is a common misconception that water freezes at 0°C (32°F). In clouds, water may remain liquid until -37 to -40°C (-35 to -40°F). At temperatures warmer than this, water molecules must collect around small particles that can help form ice, called ice nuclei. Numerous ice nuclei have been identified, ranging from dirt and dust, to volcanic ash, and even to pollen, fungi, and bacteria. One of these bacteria, Pseudomonas syringae, was identified as an ice nucleus in the 1970’s when it was discovered that it was increasing susceptibility of corn to frost damage. Since then, other Pseudomonas species as well as other bacteria within the same family of bacteria have been shown to have the ability to freeze water at relatively warm temperatures utilizing a specialized protein. Despite numerous studies on how these bacteria can exist in the atmosphere and how they can freeze water, the extent of this freezing ability, the concentration of bacteria in precipitation, and how cloud chemistry affects these bacteria has not been widely studied. In this study, precipitation was collected over the course of 15 months and the bacteria found within the collected precipitation were checked to see if they could act as ice nuclei. We found many of the previously described bacterial ice nuclei in the precipitation samples, but also identified a previously unidentified bacterium capable of freezing water. This bacterium, Lysinibacillus parviboronicapiens, does not use the same method of freezing as the other described bacterial ice nuclei. As such, we set out to determine the method it uses. We have determined that this bacterium utilizes a heat-stable, nanometer-sized particle that is not a protein. To better understand this molecule, representative strains of each species of this genus of bacteria were tested for their ability to freeze water, however, only this species has the ability. To further identify the molecule, UV radiation was used to disrupt the bacteria’s ability to freeze water, and the genes responsible were identified. Based on these results, we have tentatively identified the responsible genes as part of a polyketide synthase gene cluster. This gene cluster is responsible for producing small molecules that provide some survival advantage for the bacteria, in our case, possibly the ability to freeze water. As a final step, and to help serve other researchers, a comprehensive analysis of the entire Lysinibacillus genus has been performed and a reference guide has been generated to help describe and distinguish individual species.

13 pp. / The Make a Splash with Project WET Arizona Water Festival program is in its ninth year and served 12 communities in the 2008-2009 school year. The program trained 622 volunteers to deliver engaging water education to 6,924 fourth graders and their 313 teachers. With the support of the Bureau of Reclamation, Arizona Project WET has conducted a summative evaluation, and is able to use that information to further increase the effectiveness of the program while simultaneously documenting successes in student learning and community engagement in water education.

Numerische Experimente wurden durchgeführt, um den Einfluß von Gittermaschenweite und subskaliger Heterogenität auf die Vorhersage der am Wasserkreislauf beteiligten Größen zu untersuchen. Die Modellergebnisse zeigen, daß die Evapotranspiration, Bewölkung und der Niederschlag von der Gittermaschenweite und der Heterogenität beeinflußt werden. Es zeigte sich, daß bei Verwendung gröberer Maschenweiten unter Einbezug der verschiedenen Landnutzungstypen innerhalb der Gittermasche die Obertlächenprozesse und Phänomene (z.B. Wärmeinseleffekt) realistischer beschrieben werden, als wenn nur ein Landnutzungstyp für das gesamte Gitterelement angenommen wird. / Numerical experiments were performed to investigate the influence of grid resolution and subgrid heterogeneity on the prediction of the quantities of the water cycle. The results were compared with each other and with those provided by a simulation using the same surface parameterization scheme but taking subgrid scale surface heterogeneity into account. The model results substantiate that the evapotranspiration, cloudiness and precipitation are affected by the grid resolution and the heterogeneity. lt was found that increasing the grid size but including the heterogeneity describes more realistically the surface processes and phenomena (e.g„ heat island effect) than assuming one land use type for the whole grid element.

Wooded plant encroachment has dramatically changed the composition of rangelands in the arid and semiarid rangelands of the southwestern United States and may have significantly affected hydrologic and biogeochemical process in these environments. In particular, suspicions that encroaching species waste an undue amount of water through evapotranspiration (ET) has prompted much discussion concerning the possibility of using brush control to enhance water supplies in Texas. This study focuses on two broad goals for evaluating the effects of wooded growth in rangelands. The first of these is the assessment of wooded cover with the use of remotely sensed imagery. A methodology for delineating differing land cover classes, including different levels of brush cover, is described, applied, and validated for the Upper Guadalupe River watershed, Texas. This portion of the research resulted in an 81.81% success rate for correctly matching land cover varieties and showed that 88.8% of the watershed was covered with various amounts of woody plant growth. The second portion of this study incorporated the previously developed land cover product along with a number of other highly detailed data sources to model the North Fork of the Upper Guadalupe River watershed using the Soil and Water Assessment Tool (SWAT). The role of topography, brush cover, and soil slope, which are hypothesized to contribute to successful implementation of brush removal for water yield, were tested in a scientifically conscious and practical experiment to determine their influence upon water availability at a watershed scale. The effects of brush removal were found to be comparable to the quantities documented in field experiments, but less than the levels presented in previous modeling studies. Brush density was found to be the most important factor in determining locations for successful brush removal in regards to reducing ET. Slope was also found to have significant effect in increasing lateral flow while shallow soil had lesser effects on hydrology than other criteria. Large quantities of deep recharge simulated by the model raise questions concerning measurement of ET in the Edwards Plateau region and the extent of deep water recharge to the Trinity Aquifer.

Wooded plant encroachment has dramatically changed the composition of rangelands in the arid and semiarid rangelands of the southwestern United States and may have significantly affected hydrologic and biogeochemical process in these environments. In particular, suspicions that encroaching species waste an undue amount of water through evapotranspiration (ET) has prompted much discussion concerning the possibility of using brush control to enhance water supplies in Texas. This study focuses on two broad goals for evaluating the effects of wooded growth in rangelands. The first of these is the assessment of wooded cover with the use of remotely sensed imagery. A methodology for delineating differing land cover classes, including different levels of brush cover, is described, applied, and validated for the Upper Guadalupe River watershed, Texas. This portion of the research resulted in an 81.81% success rate for correctly matching land cover varieties and showed that 88.8% of the watershed was covered with various amounts of woody plant growth. The second portion of this study incorporated the previously developed land cover product along with a number of other highly detailed data sources to model the North Fork of the Upper Guadalupe River watershed using the Soil and Water Assessment Tool (SWAT). The role of topography, brush cover, and soil slope, which are hypothesized to contribute to successful implementation of brush removal for water yield, were tested in a scientifically conscious and practical experiment to determine their influence upon water availability at a watershed scale. The effects of brush removal were found to be comparable to the quantities documented in field experiments, but less than the levels presented in previous modeling studies. Brush density was found to be the most important factor in determining locations for successful brush removal in regards to reducing ET. Slope was also found to have significant effect in increasing lateral flow while shallow soil had lesser effects on hydrology than other criteria. Large quantities of deep recharge simulated by the model raise questions concerning measurement of ET in the Edwards Plateau region and the extent of deep water recharge to the Trinity Aquifer.

Orientador: Roberto Greco / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Geociências / Made available in DSpace on 2018-08-27T00:29:45Z (GMT). No. of bitstreams: 1 Alves_EmersonJhammesFrancisco_M.pdf: 3241994 bytes, checksum: 88f0626f7e0bab38cef4994358916c94 (MD5) Previous issue date: 2014 / Resumo: A presente pesquisa visa propor um método capaz de analisar os livros didáticos e verificar a presença e o nível da abordagem sistêmica. A análise é feita no tema ciclo hidrológico apresentado nas coleções de livros de Ciências e Geografia. O interesse é propor um procedimento capaz de compreender como abordagem sistêmica é apresentada. A metodologia utiliza são mapas conceituais que visa analisar palavras, processos, esferas terrestres, imagens e conceitos relacionados ao ciclo hidrológico. Além disso, são quantificados os agentes como: evaporação, condensação, precipitação, vento, rio, vegetação, sol entre outros. Ao longo da pesquisa é caracterizado um novo método para analisar as coleções de livros didáticos de Geografia e Ciências, focando questões relacionadas aos aspectos na abordagem sistêmica a partir do estudo do ciclo hidrológico. Dentre a construção do método utilizado nessa pesquisa o mapa conceitual se destacou, sendo capaz de quantificar e sistematizar as esferas do ciclo hidrológico. Esse método nos leva a identificação da abordagem sistêmica ou analítica nas coleções de livros didáticos de Geografia e Ciências, e contribui para o uso da noção de sistemas na observação de fenômenos cíclicos, a estruturação de conceitos, processos por meio de mapas conceituais e compreendendo a abordagem sistêmica na totalidade dos fenômenos ocorrentes no ambiente natural / Abstract: This research aims to propose a method to analyze the textbooks and verify the presence and the level of systemic approach. The analysis is based on the theme hydrological cycle presented in the collections of Science and Geography books. The interest is to propose a procedure capable of understanding how systemic approach is presented. The methodology uses are conceptual maps that aim to analyze words, processes, terrestrial spheres, images and concepts related to the hydrological cycle. In addition, agents are quantified as: evaporation, condensation, precipitation, wind, river, vegetation, sun and more. During the research is characterized a new method for analyzing the collections of textbooks of Geography and Sciences, focusing on issues related to aspects of the systems approach from the study of the hydrological cycle. Among the construction of the method used in this research the concept map stood out, being able to quantify and systematize the spheres of the hydrological cycle. This method leads to identification of systemic or analytical approach in the collections of textbooks of Geography and Sciences, and contributes to the use of the concept of systems in observation of cyclic phenomena, structuring concepts, processes through concept mapping and understanding the systemic approach to all the phenomena occurring in the natural environment / Mestrado / Ensino e Historia de Ciencias da Terra / Mestre em Ensino e Historia de Ciencias da Terra

Salinity is one of the fundamental ocean state variables. Variations of ocean salinity can be used to infer changes in the global water cycle and air-sea freshwater exchange. Many institutions have developed gridded Argo products of global coverage. However, the existing gridded salinity products have not yet been dedicatedly intercompare and assessed. In this study, the mean state, annual and interannual variabilities, and decadal changes of ocean salinity from five Argo-based gridded salinity products, available from UK Met Office, JAMSTEC, Scripps Institution of Oceanography, China Second Institute of Oceanography, and International Pacific Research Center, are examined and compared for their overlapping period of 2005-2015 within two depth intervals (0-700 m and 700-2000 m), as well as the sea surface. Though some global and regional features are relatively reproducible, obvious discrepancies are found particularly for the deeper layer. These discrepancies are not apparent on the 11-year climatological mean or the trend patterns, but are readily evident on temporal variations. For instance, the potentially undersampled current systems in the North Atlantic and Southern Ocean are one of the main reasons for the observed discrepancies. The gridded products from Scripps, JAMSTEC and Met Office show large deviation from the ensemble mean, particularly in regions like the Atlantic Ocean and the tropical Pacific. Large disagreements are found in the first and final years, which can lead to different estimates on decadal trends. This study can serve as a useful reference on how to utilize and improve the existing gridded salinity products.

<p>A lack of water supplies can pose a serious threat to municipalities, industries, agriculture, and the environment. In order to make more resilient water allocations, it is helpful to quantify water resources. Water abstraction from aquifers, water diversions, and dams that regulate flow are some of the anthropogenic activities that directly affect the water cycle. The evaluation of water resources is complicated by such human alterations. In low-flow months, baseflow cannot be accurately evaluated without separating the impact of reservoir management, since the flow comes not only from groundwater but also slow releases from water management. Streamflow naturalization is required for determining the impact of environmental changes on streamflow trends and better predicting future water availability, so historical daily data were used to estimate daily naturalized streamflow for six sites in the Upper Wabash basin. Based on a comparison of observed and naturalized data for the same period (1968-2014), reservoir management has little impact on annual water levels. The influence of reservoir management is more pronounced seasonally and for the upstream stations. The naturalized mean monthly flow for March of the Salamonie River at Dora (upstream) is 24% higher than the observed mean monthly flow, while the naturalized mean monthly flow for September is 59% lower than the observed mean monthly flow. Long-term (63 to 91 years) unmanaged streamflow statistics for the Wabash River basin revealed statistically significant upward trends in flashiness, mean, flow peaks and low flows.</p> <p>On the other hand, many locations that have traditionally relied on surface water resources, are increasingly utilizing ground water during times of shortage. The increasing use of both surface and groundwater resources requires management tools that can represent these resources at regional scales. In this study, the Variable Infiltration Capacity (VIC) model was modified to account for groundwater storage and withdrawals, and it is referred to as VIC Groundwater (VICGW). In VICGW, aquifer storage is represented through the inclusion of an additional subsurface layer and a new groundwater flow pathway. With the representation of groundwater withdrawals, storage, and a groundwater flow pathway, the baseflow index (BFI) is better represented and increased by 2% in comparison to traditional VIC simulations and the average monthly streamflow is also increased by 23% for the months of August to October.</p> <p><br></p> <p>Since water is not always available when and where it is needed, climate trends and changing use patterns require better quantification of future water allocations. To evaluate the impact of projected changes in supply and groundwater demand on watershed scale hydrology, groundwater withdrawals have been projected considering both socioeconomic and climatic factors. From 2020-2060, groundwater withdrawals have been projected for each county in Indiana. Using past trends and the regional growth and decay term, water use efficiency was modeled for different sectors. The projections include not only socioeconomic factors such as population, income, and irrigated land, but also climatic factors such as projected air temperature, precipitation, and evapotranspiration. Domestic and public, industrial and commercial, thermoelectric power, irrigation, livestock, and mining sectors all saw a decrease in water withdrawal per demand unit, while aquaculture was the only sector to see an increase in use. There has been an increase in withdrawals across the state of Indiana, while some counties have projected decreases. Without considering climate change, the projected withdrawals in 2060 will be 3464 million L/d, an increase of 12% over 2015. Climate change is predicted to increase water withdrawals by 20% under a lower representative concentration pathway (RCP 4.5) and 22% under the higher representative concentration pathways (RCP 8.5).</p> <p>Future water supply was projected with VICGW simulations utilizing statistically downscaled climate data. As a result of an increase in future demand, there was a slight reduction in simulated Base Flow Index. Mean annual runoff was estimated to increase by 43 mm annually for 2041-2060, relative to 2015, due to changing supply. Wetter conditions due to changes in climate resulted in an overall rise in the annual mean water table across most of the Upper Wabash basin. Due to changes in demand and supply, the seasonal maximum water table decline across all the grid cells was projected to be 117 cm and 197 cm, respectively. This study evaluates how future water supply and use will affect watershed hydrology and can provide a basis for policymakers and stakeholders to consider future adaptations.</p>

This study examined the use of discovery learning in science and how it affects students' academic performance as well as their self-efficacy in science. It also used a diagnostic tool to identify students' misconceptions about processes in the water cycle and where the misconceptions originated. While the study showed that the treatment group had a statistically significant greater academic gain from the pre-test to the post- test than did the no-treatment comparison group, from a teachers view point the gain would not be enough to benefit a student's performance on high stakes tests. Because the study was able to identify eight common misconceptions, it suggests that the misconceptions that students possess are difficult to uproot even using teaching methods that have been proven successful. / CITE/Mathematics and Science Education

The land surface and atmosphere interact through complex feedback loops that link energy and water cycles. Effectively characterizing these linkages is critical to modeling weather and climate extremes accurately. Seasonal variability in vegetation growth and human-driven land cover changes (LCC) can alter the biophysical properties of the land surface, which can in turn influence the water cycle. We quantified the impacts of seasonal variability in vegetation growth on land surface energy and water balances using ecosystem-scale eddy covariance and large aperture scintillometer observations. Our results indicated that the monthly precipitation and seasonal vegetation characteristics such as leaf area index, root length, and stomatal resistance are the main factors influencing ecosystem land surface energy and water balances when soil moisture and available energy are not limited. Using a regional-scale climate model, we examined the effect of LCC and irrigation on summer water cycle characteristics. Changes in biophysical properties due to LCC reducing the evapotranspiration, atmospheric moisture, and summer precipitation over the contiguous United States (CONUS). The combined effects of LCC and irrigation indicated a significant drying over the CONUS, with increased duration and decreased intensity of dry spells, and reduced duration, frequency, and intensity of wet spells. Irrigated cropland areas will become drier due to the added effect of low-precipitation wet spells and long periods (3-4% increase) of dry days, whereas rainfed croplands are characterized by intense (1-5% increase), short-duration wet spells and long periods of dry days. An analysis based on future climate change projections indicated that 3–4 °C of warming and an intensified water cycle will occur over the CONUS by the end of the 21st century. The results of this study highlighted the importance of the accurate representation of seasonal vegetation changes and LCC while forecasting present and future climate. / Doctor of Philosophy / The land surface and atmosphere interact through complex feedback loops that link energy and water cycles. Effectively characterizing these linkages is critical to accurately model weather and climate extremes. We quantified the influence of human-driven land cover change (LCC), in this case, LCC associated with irrigated agriculture, and seasonal vegetation growth on the water cycle using a regional climate model and ecosystem-level observations. Our results indicated that monthly precipitation and seasonal vegetation growth are the main factors influencing land surface energy and water balances when soil moisture and solar energy are not limited. Our results showed that irrigation-related LCC reduced summer precipitation over the contiguous United States (CONUS), with an increased number of dry days (days with less than 1 mm precipitation) and reduced hourly, daily, and summer precipitation totals. Irrigated cropland areas are becoming drier due to the combined effects of low precipitation and long dry days, whereas rainfed croplands are characterized by intense short-duration precipitation and long dry days. Climate change analyses indicate that 3–4 °C of warming and an intensified water cycle will occur over the CONUS by the end of the 21st century. The results of this study highlight the importance of the accurate representation of LCC while forecasting future climate.