Comparison of MAGIC and Diatom paleolimnological model hindcasts of lakewater acidification in the Adirondack region of New York

Thirty-three lakes that had been statistically selected as part of the US Environmental Protection Agency's Eastern Lake Survey and Direct Delayed Response Project (DDRP) were used to compare the MAGIC (watershed) and Diatom (paleolimnological) models. The study lakes represented a well-defined group of Adirondack lakes, each larger than 4 ha in area and having acid-neutralizing capacity (ANC) <400 {mu}eq L{sup {minus}1}. The study first compared current and pre-industrial (before 1850) pH and ANC estimates from Diatom and MAGIC as they were calibrated in the preceding Paleocological Investigation of Recent Lake Acidification (PIRLA) and DDRP studies, respectively. Initially, the comparison of hindcasts of pre-industrial chemistry was confounded by seasonal and methodological differences in lake chemistry data used in calibration of the model. Although certain differences proved to be of little significance for comparison, MAGIC did predict significantly higher pre-industrial ANC and pH values than did Diatom, using calibrations in the preceding studies. Both models suggest acidification of low ANC Adirondack region lakes since preindustrial times, but differ primarily in that MAGIC inferred greater acidification and that acidification has occurred in all lakes in the comparison, whereas Diatom inferred that acidification has been restricted to low ANC lakes (<about 50 {mu}eq L{sup {minus}1}). 133 refs., 30 figs., 16 tabs

Phytoplankton Community as an Indicator of Cyanobacteria Harmful Algal Blooms in High Mountain Lakes

Cyanobacteria blooms are a growing issue worldwide and can be harmful to both aquatic life and human health. Warm temperatures, nutrient loading, stable water columns, and selective grazing of zooplankton and phytoplankton can contribute to cyanobacteria bloom formation. In this study, I characterized the algal communities and water quality differences in two physiographically similar lakes with relatively little human influences, Odell and Crescent Lakes, Oregon, to better understand potential contributing factors to cyanobacteria harmful algal bloom formation (cyanobacteria bloom) in Odell Lake. There are three hypotheses in this study: If there was a cyanobacteria bloom in Odell Lake, but not Crescent Lake, then the algal community in Odell Lake would be representative of eutrophic conditions while Crescent Lake would not. If temperature was a contributing factor to community shifts in either Odell Lake or Crescent Lake, then temperature would have significant changes associated with phytoplankton shifts and cyanobacteria abundance. If nutrients were a contributing factor to cyanobacteria abundance, then the lake would experience increases in nutrient concentrations prior to cyanobacteria blooms formation. Phytoplankton samples were collected from Odell and Crescent lakes on a weekly basis from June 2019 to September 2019 and characterized via microscopy. Multiparameter sondes were places in each lake at a fixed depth within one meter of the surface and recorded temperature (degrees C), pH, dissolved oxygen (mg/L and percent concentration), specific conductance (µS/cm), phycocyanin (relative fluorescence units; RFU), and chlorophyll-a (RFU) every 15-minutes throughout the study period. The phytoplankton community in Odell Lake was characterized by high abundances of eutrophic phytoplankton taxa, such as cyanobacteria, which had an average relative abundance of total density of 59.8 ± 30.3% (n=13; average ± standard deviation) throughout the sampling period. Crescent Lake was dominated by the phyla Bacillariophyta (diatoms) and Ochrophyta which had an average relative abundance of total density of 28.6 ± 14.0% and 20.9 ± 14.8%, respectively. Odell Lake transitioned from phytoplankton adapted to mesotrophic conditions and sensitive to stratification to phytoplankton found in eutrophic conditions and stratified water columns. Crescent Lake shifted from oligotrophic and mesotrophic algal taxa to a high abundance of cyanobacteria, however no visible bloom ever formed. A generalized additive mixed model of temperature data showed water temperature in Odell Lake was significantly warmer, on average 0.72 ± 0.92°C, than that of Crescent Lake as the bloom approached, which supported my second hypothesis. Nutrient measurements also supported the third hypothesis, as phytoplankton abundance in Odell Lake was significantly correlated with total phosphorus (TP; R-squared = 0.97; p \u3c 0.05) and total nitrogen (TN; R-squared = 0.99; p \u3c 0.05). Concentrations of orthophosphate peaked prior to cyanobacteria bloom formation, which when coupled with potential silica limitation in Odell Lake was likely responsible for promoting cyanobacteria abundance and cyanobacteria bloom formation dominated by N-fixer due to favorable nitrogen limiting conditions (TN:TP \u3c 7) and reduced competition between cyanobacteria and diatoms due to silica limitation. Overall, this study found temperature was correlated with cyanobacteria bloom presence and intensity in Odell Lake, and nutrient conditions were more favorable to cyanobacteria dominance in Odell Lake versus Crescent Lake. The information provided in this study can be used with additional information could be used with additional information, such as lake orientation, wind patterns, and food web dynamics, to better understand factors contributing to cyanobacteria bloom formation in high mountain lakes

Particulate Matter Emitted from Gravel Crushers and Their Health Impacts on Workers, Middle Governorate - Gaza, Palestine

Background: Particulate matter (PM) refers to discrete particles in ambient air that exist as either solid or liquid droplets. A crusher is a machine designed to crush and grind rocks or rubble resulting from construction waste, and convert it to materials can be re-used in the building and construction. Aim: To evaluate the level of PM10 air pollution in crushers plants, and their impacts on respiratory system health, vital signs and complete blood count for crushers workers. Material and Methods: Case-control study was conducted during the period from April to August 2013 on all gravel crushers at Middle Gaza Governorates. 87 individuals participated, case (exposed) and control (non exposed) groups contain 40, 47 respectively. Pm10 concentration level was measured in the six crushers, and all participants were subjected to questionnaire, vital signs measuring, and complete blood counts Results: Results showed that an average of particulate matter contributions is 15153 μg/m3, which is about 100 times higher than PM10 existing standard of 150 μg/m3. As well as, it showed clear links between PM10 exposure and respiratory health, vital signs, and white blood cells among exposed group. Cough, dyspnea and sputum buildup were more common among the exposed group 100%, 97.5%, and 82,5% respectively, the non exposed group 14.9%, 31,9%, and 28.6%, respectively. Increasing in white blood cells count and Vital signs disturbances (Increasing systolic and diastolic blood pressure, increasing pulse rate, increasing respiratory rate and temperature) reported significantly among the exposed workers. Conclusions: PM10 concentration level in crushers plants were much higher than the existing standard. Occupational exposure to PM10 leads to higher prevalence of respiratory symptoms, vital signs disturbance, and increasing WBCs. Recommendations: Environmental and engineering control of PM10 emissions, protective techniques, procedures, measures and equipment and periodic medical examinations

The effects of stenting and endothelial denudation on experimental aneurysm healing and gene expression following endovascular treatment

Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal

Development of a "genome-proxy" microarray for profiling marine microbial communities, and its application to a time series in Monterey Bay, California

Thesis (Ph. D.)--Joint Program in Biological Oceanography (Massachusetts Institute of Technology, Dept. of Biology; and the Woods Hole Oceanographic Institution), 2008.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.Includes bibliographical references (p. 155-181).This thesis describes the development and application of a new tool for profiling marine microbial communities. Chapter 1 places the tool in the context of the range of methods used currently. Chapter 2 describes the development and validation of the "genome proxy" microarray, which targeted marine microbial genomes and genome fragments using sets of 70-mer oligonucleotide probes. In a natural community background, array signal was highly linearly correlated to target cell abundance (R² of 1.0), with a dynamic range from 10²-10⁶ cells/ml. Genotypes with >/=~80% average nucleotide identity to those targeted crosshybridized to target probesets but produced distinct, diagnostic patterns of hybridization. Chapter 3 describes the development an expanded array, targeting 268 microbial genotypes, and its use in profiling 57 samples from Monterey Bay. Comparison of array and pyrosequence data for three samples showed a strong linear correlation between target abundance using the two methods (R²=0.85- 0.91). Array profiles clustered into shallow versus deep, and the majority of targets showed depth-specific distributions consistent with previous observations. Although no correlation was observed to oceanographic season, bloom signatures were evident. Array-based insights into population structure suggested the existence of ecotypes among uncultured clades. Chapter 4 summarizes the work and discusses future directions.by Virginia Rich.Ph.D

Fabrication of tubular ceramic oxygen-electrolyte membrane reactor

Ph.DDOCTOR OF PHILOSOPH