<p> ¹⁰Be_met, or cosmogenic beryllium, has a long half-life of 1.4 million years and quick adsorption on soil particles, which may make it ideal for dating soil erosion in historical context. However, there are questions on about the fundamental assumptions of the retentivity of ¹⁰Be_met. This manuscript explores these assumptions and the context of nutrient cycling in a natural forest setting. </p><p> To see if ¹⁰Be_met was being cycled through the trees, and at what rate, we looked at the[¹⁰Be_met] in the soil, 4 species of trees, and their leaves. The isotopic ratio¹⁰Be/⁹Be in all four tree species was comparable to the soil on which they grow, ranging from 6-8 x 10 ^-9. However, there was one exception with hickory (<i>Carya spp.</i>) which strongly bioaccumulate beryllium with an average of 0.38 ppm dry weight in the wood. Abscised hickory leaves have a higher [Be] of 2.0 ppm, over 10 times higher than in the soil. </p><p> Using standard allometric equations relating tree biomass to trunk diameter, and assuming that belowground biomass has the same [Be] as aboveground, we calculate that hickory trees at our site contain approximately 1% of the total ¹⁰Be_met under their canopy and that ~10% of this Be is cycled annually by leaf abscission. It is not clear at this point what fraction of litterfall Be is recycled into the plant, returned to the soil, or carried to groundwater as organic chelates. </p><p> Hickory trees occupy an average of ~10% of the oak-hickory forest area. Assuming that trees are randomly distributed, that litterfall Be is returned to the soil, and maintaining a constant ¹⁰Be_met budget over time for simplicity, then more than half of all ¹⁰Be_met in the forest soil will have passed through a hickory tree over the past 10 ky. Fully 90% of all ¹⁰Be_met will pass through a hickory tree over a period of ~25 ky. It is clear that hickory trees can transport a sizable fraction of the total ¹⁰Be_met in their nutrient cycle, and that they may be responsible for landscape-scale Be mobility.</p>

<p> This research seeks to understand how people in the Denver metropolitan area perceive and remember weather, climate, and climate change and how social, demographic, and environmental factors might influence these perceptions and memories. To do this, an online survey was completed in 2006 and in-person interviews were conducted in 2010 and 2011. The online survey and the in-person interviews both asked questions about recent weather, seasonal climate for specific years, beliefs about climate change and human impact on climate change, and social and demographic information. During the 2010&ndash;2011 in-person interviews, ambient meteorological conditions were recorded. For climate recollections, overall accuracy was about 20%. In general, women who were politically liberal, majored in a science field, believed in climate change, and were in a good mood were the most accurate for past climates. However, this accuracy was still only about 30%. For recent weather memories, the accuracy was about 50%. Time was the biggest indicator of accuracy, with the most recent weather being remembered the most accurately. When asked to rate the weather from positive to negative for specific events, respondents reported the weather with a negative bias for extremely negative flashbulb memory events. For perceptions about climate change, over 80% of the respondents in the Denver metropolitan area believed global warming was occurring and that humans had an impact on global warming. Over 80% of respondents believed that global warming will impact the Denver metropolitan area, however not all of these people knew how climate change would impact them personally. </p>

<p> Natural disasters can be very devastating to the public during their impact phase. After a natural disaster impacts a region, the response and recovery phases begin immediately. Weather conditions may interrupt emergency response and recovery in the days following the disaster. This study analyzes the climatology of weather conditions during the response and recovery phases of hurricanes and tornadoes to understand how weather may impact both environment and societal needs. Using specific criteria, 66 tornadoes and 16 hurricane cases were defined. National Weather Service (NWS) recognized weather stations were used to provide temperature, precipitation, snowfall, relative humidity, wind speed, and wind direction data. Regional and temporal groups were defined for tornado cases, but only one group was defined for hurricanes. By applying statistical analysis to weather observations taken in the week following the disasters, a climatology was developed for the response and recovery phase. Tornado and hurricane post-disaster climate closely mimicked their synoptic climatology with cooler and drier weather prevailing in days 2-4 after a disaster until the next weather system arrived about 5 days later. Winter tornadoes trended to occur in the Southeast and were associated with more extreme temperature differences than in other regions and season. The results of this study may help governmental and non-governmental organizations prepare for weather conditions during the post-disaster phase.</p>

Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 2006. / Source: Dissertation Abstracts International, Volume: 68-02, Section: B, page: 1171. Adviser: Farzad Kamalabadi. Includes bibliographical references (leaves 108-114) Available on microfilm from Pro Quest Information and Learning.

Thesis (Ph. D.)--University of California, Irvine, 2007. / (UMI)AAI3282781. Source: Dissertation Abstracts International, Volume: 68-09, Section: B, page: 5972. Adviser: Donald R. Blake.

Thesis (Ph. D.)--University of Illinois at Urbana-Champaign, 2006. / Source: Dissertation Abstracts International, Volume: 67-11, Section: B, page: 6253. Adviser: Susan M. Larson. Includes bibliographical references (leaves 238-245). Available on microfilm from Pro Quest Information and Learning.

abstract: The atmosphere contains a substantial amount of water soluble organic material, yet despite years of efforts, little is known on the structure, composition and properties of this organic matter. Aqueous phase processing by fogs and clouds of the gas and particulate organic material is poorly understood despite the importance for air pollution and climate. On one hand, gas phase species can be processed by fog/cloud droplets to form lower volatility species, which upon droplet evaporation lead to new aerosol mass, while on the other hand larger nonvolatile material can be degraded by in cloud oxidation to smaller molecular weight compounds and eventually CO2. In this work High Performance Size Exclusion Chromatography coupled with inline organic carbon detection (SEC-DOC), Diffusion-Ordered Nuclear Magnetic Resonance spectroscopy (DOSY-NMR) and Fluorescence Excitation-Emission Matrices (EEM) were used to characterize molecular weight distribution, functionality and optical properties of atmospheric organic matter. Fogs, aerosols and clouds were studied in a variety of environments including Central Valley of California (Fresno, Davis), Pennsylvania (Selinsgrove), British Columbia (Whistler) and three locations in Norway. The molecular weight distributions using SEC-DOC showed smaller molecular sizes for atmospheric organic matter compared to surface waters and a smaller material in fogs and clouds compared to aerosol particles, which is consistent with a substantial fraction of small volatile gases that partition into the aqueous phase. Both, cloud and aerosol samples presented a significant fraction (up to 21% of DOC) of biogenic nanoscale material. The results obtained by SEC-DOC were consistent with DOSY-NMR observations. Cloud processing of organic matter has also been investigated by combining field observations (sample time series) with laboratory experiments under controlled conditions. Observations revealed no significant effect of aqueous phase chemistry on molecular weight distributions overall although during cloud events, substantial differences were apparent between organic material activated into clouds compared to interstitial material. Optical properties on the other hand showed significant changes including photobleaching and an increased humidification of atmospheric material by photochemical aging. Overall any changes to atmospheric organic matter during cloud processing were small in terms of bulk carbon properties, consistent with recent reports suggesting fogs and clouds are too dilute to substantially impact composition. / Dissertation/Thesis / Doctoral Dissertation Chemistry 2014

abstract: The characteristics of the wintertime 500hPa height surface, the level of non-divergence and used for identifying/observing synoptic-scale features (ridges and troughs), and their impact on precipitation are of significance to forecasters, natural resource managers and planners across the southwestern United States. For this study, I evaluated the location of the 500hPa mean Pacific ridge axis over the winter for the period of 1948/49 to 2011/12 and derived the mean ridge axis in terms of location (longitude) and intensity (geopotential meters) from the NCEP/NCAR Reanalysis dataset. After deriving a mean ridge axis climatology and analyzing its behavior over time, I correlated mean location and intensity values to observed wintertime precipitation in select U.S. Climate Divisions in Arizona, Colorado, Nevada, Utah and New Mexico. This resulted in two findings. First specific to the 500hPa ridge behavior, the ridge has been moving eastward and also has been intensifying through time. Second, results involving correlation tests between mean ridge location and intensity indicate precipitation across the selected Southwest Climate Divisions are strongly related to mean ridge intensity slightly more than ridge location. The relationships between mean ridge axis and observed precipitation also are negative, indicating an increase of one of the ridge parameters (i.e. continued eastward movement or intensification) lead to drier winter seasons across the Southwest. Increased understanding of relationships between upper-level ridging and observed wintertime precipitation aids in natural resource planning for an already arid region that relies heavily on winter precipitation. / Dissertation/Thesis / M.A. Geography 2013

An increase in worldwide industrialized shark fisheries resulting from the growing demand for shark products, especially shark fins in Asian markets, as well as high levels of bycatch mortality associated with multi-species fisheries have raised suspicions of substantial declines in global shark populations. Due to varying responses by individual species to fishing pressure, it has become necessary to manage sharks on a species-specific basis, which requires the collection of more accurate catch and trade data. The accumulation of such data is hindered, however, by difficulties in identifying species from only landed carcasses, body parts, or fins. This is especially true for many of the commercially important carcharhinid (Family Carcharhinidae) sharks, which are easily confused with one another due to strong morphological similarities and overlapping distributions. The forensic assays described in this thesis expand on a molecular approach developed in the M. Shivji laboratory (Guy Harvey Research Institute, Nova Southeastern University) to resolve these shark species identification issues and allow for rapid and accurate identification of shark body parts. The method involves the development of species-specific primers based on interspecific DNA nucleotide polymorphisms within the nuclear ribosomal internal transcribed spacer 2 (ITS2) locus, and inclusion of these primers in highly streamlined multiplex polymerase chain reaction (PCR) assays. Chapter One describes two separate multiplex PCR assays, each addressing different forensic objectives for U.S. Atlantic and global populations of seven carcharhinid shark species, known as the ridgeback sharks: night (Carcharhinus signatus), dusky (Carcharhinus obscurus), Caribbean reef (Carcharhinus perezi), sandbar (Carcharhinus plumbeus), bignose (Carcharhinus altimus), silky (Carcharhinus falciformis), and tiger (Galeocerdo cuvier). An assay is described in Chapter Two for distinguishing the bull (Carcharhinus leucas) and Java (Carcharhinus amboinensis) shark, carcharhinid species that display high levels of morphological similarity as well as similar habitat preference and distributions. The development of species-specific primers for identification of two additional carcharhinid shark species found in international fin markets, gray reef (Carcharhinus amblyrhynchos) and spottail (Carcharhinus sorrah), is detailed in Chapter Three. All of the assays and primers presented here have proven effective for various applications in domestic and international fisheries law enforcement, shark species management, and conservation. The efficient, economical, and simple basis of the assay lends itself to widespread routine application in practical contexts, such as collection of species-specific shark catch and trade data and clarification of the extent of species distributions. Further confirmation of the utility of this assay on a global scale is found in the success of this approach and individual primers for identifying dried shark fins from the Hong Kong fin market, confiscated fins from the U.S., South Africa, Guam, and Palau, and unknown identity samples from a Madagascar fishery.

Batch cultures of the cyanobacteria Synechococcus spp. (strains 48 Syn and 2346) and Porphyridium cruentum (Rhodophyta) were grown in nitrogen-limited (N:P=4:l) and phosphorus-limited (N:P=50:l) seawater media. Optical properties, including particle size (forward angle light scatter), particle granularity (right angle light scatter) and relative mean channel red (> 600 nm) and green (510-550 nm) fluorescence were measured for 10 days using a flow cytometer. Dissolved nitrogen (nitrate), phosphorus (phosphate), cell abundance and chlorophyll concentrations were also measured. Results indicated that phosphorus-limited cultures yield higher chlorophyll concentration, fluorescence and granularity (right angle scatter) values than did nitrogen-limited cultures. Comparison of these samples with a preliminary investigation shows nutrient-rich cultures (N:P=4:l, N:P=50:l) have larger particle size and higher fluorescence values than relatively nutrient-poor cells cultured in f/20 media. Secondary (R2) populations have been determined for all samples, either by light scatter or fluorescence anomalies. Particularly notable was Synechococcus 2346 (phosphorus-limited) which exhibited a secondary population characteristic for more than half of the experiment. Highly fluorescent particles are suggested as either formative daughter cells, cellular “clumping" or a cellular optical response to batch culture turbidity; these particles have a profound influence on the relative refractive index of the culture with time. Flow cytometric analysis can be an effective tool in the determination of not only differences in the optical properties and fluorescent signatures of various cyanobacterial strains, but also of population variation within a single strain.