The long-term study for the environmental-hydrologic observatory in Pool 16 of the Mississippi RIver includes installing modern sensors to continuously record the nutrient loads at the entrance, the exit and in other pertinent locations of Pool 16. Multiple monitoring locations allows more accurate modeling of nutrients and the sensors can be strategically placed to record nutrient load patterns due to floods, seasonal patterns due to agricultural trends and/or weather, the function of nutrient processing within the pool, or other major occurrences (Carver, 2008). The fact that no other organization has the current ability to record continuous, real-time nutrient data within the Mississippi River provides reason that the Pool 16 observatory may have a significant part in redefining nutrient transport in the Upper Mississippi River Basin and the understanding of the Gulf hypoxia (Carver, 2008). Six high-tech sensors have been deployed in Pool 16 from 2008-2010 recording real-time data such as nitrate, dissolved oxygen, turbidity, temperature and pH. The sensors have collected real-time data at the following locations (Figure 1.3): * Lock and Dam 15 * mouth of the Rock River * along the river bank at the town of Buffalo, IA * in the backwaters of Andalusia Island * along the river bank at LACMRERS * Lock and Dam 16. The collected data now needs to be analyzed not only to understand the data patterns, but to determine whether the data is reliable and makes sense. The main data series that this study focuses on is nitrate concentrations. Nitrate data is analyzed based on the natural patterns observed, how nitrate concentrations are affected by occurrences, and how nitrate patterns are directly related to other measured data such as dissolved oxygen and temperature. The sensors also need to be researched to determine if they are the best piece of technology for our needs and whether the sensors are able to record reliable data. Therefore, the objectives of this study are as follows: * Deploy several sensors in a short amount of time in Pool 16 to determine the efficiency of longer term deployments. * Investigate diurnal phenomena in highly time resolved nitrate concentration data from Pool 16. * Investigate seasonal patterns in nitrate concentration data collected from sensors. * Compare diurnal phenomena and seasonal patterns in nitrate concentrations for the Raccoon River and the Mississippi River. * Evaluate sensor performance and data reliability.

Transposable elements (TEs) are acknowledged sources of genetic change within organisms. The effects of transposition can range from the disruption or creation of a single gene to large-scale genome rearrangements. Transposition events can result in beneficial mutations which allow an organism to adapt to a new environment. In the last three years, several studies have reported that some miRNAs, small RNAs involved in post-transcriptional gene regulation, have evolved from TEs. miRNAs play an important role in the stress responses of many organisms. Interestingly, TEs are derepressed under the same stress conditions that miRNAs are known to ameliorate. The observation that miRNAs are known to evolve from TEs and that TEs are derepressed under stress conditions lead me to question whether TEs play a role in environmental adaptation through the creation of small RNA networks. To test this idea, Chlamydomonas reinhardtii cultures were grown under low carbon, nitrate enriched conditions and the small RNA pool was analyzed. I found that these conditions do stimulate the expression of novel small RNAs and that some of these RNAs and their targets are derived from transposition events.

Nitrate (NO3-) is of central importance in the internal soil nitrogen (N) cycle. While animal wastes and nitrification inhibitors have been used in modern agriculture for decades, their effects on soil NO3- production in relation to ammonium (NH4+) availability and nitrifier population activity in agricultural soils receiving animal wastes or nitrification inhibitors. Several laboratory and field studies assessed the impacts of variously treated dairy wastes and the effects of repeated long-term use of a nitrification inhibitor, nitrapyrin, on microbial NO3- production and soil NO3- concentrations in Utah agricultural soils. The various process rates of N mineralization, nitrification, and microbial N immobilization were determined in laboratory and field systems using 15N isotope dilution techniques. Nitrification potentials were used simultaneously to measure the nitrifier population size and activity. Microbial NO3- immobilization was not observed in the laboratory and field experiments. The lack of microbial NO3- immobilization was not observed in the laboratory and field experiments. The lack of microbial NO3- consumption indicates that nitrification was the primary process controlling soil NO3- concentrations. Nitrifiers were not weaker competitors than heterotrophs for utilizing soil NH4+; about 50% of the NH4+ mineralized was used by nitrifiers. Low carbon availability may have limited heterotrophic microbial growth, thereby minimizing the heterotrophic microbial consumption of NH4+ and NO3-. Effects of dairy wastes on soil NH4+ availability depend on the treatment systems of dairy wastes and their application rates. The N mineralization potentials were approximately 5% of the organic N in dairy-waste compost versus 90% of the organic N in dairy waste digested anaerobically. Dairy-waste compost at appropriate application rates did not increase nitrification rates, nitrification potentials, or soil NO3- concentrations for several months following application. However, even stabilized dairy-waste compost led to high nitrification rates and potentials and elevated soil NO3- concentrations when it was applied at an excessive rate (i.e., 100 Mg dry wt. ha-1). In a dryland wheat agroecosystem, repeated use of nitrapyrin for 8 years had a 2-year residual effect observed as lower nitrification potentials in soils with a history of nitrapyrin use compared to soils without that history.

Wastewater treatment plants (WWTPs) are required to remove ammonium (NH4+) from wastewater due to its oxygen demand and toxicity to the aquatic organisms. Ammonium is removed in the activated sludge treatment system by nitrification and denitrification processes. Nitrification is the oxidation of NH4+ to nitrate (NO3-) by autotrophic nitrifying bacteria which use carbon dioxide (CO2) as a carbon source for growth. These bacteria grow slowly with low nitrification rates limiting WWTPs capacity. In this research it was hypothesized that supplying higher concentrations of CO2 during aeration increases nitrification rates, resulting in a reduction of the solids retention time (SRT). This hypothesis was tested with two lab-scale sequencing batch reactors seeded with sludge from a full-scale activated sludge WWTP and fed synthetic wastewater. The control reactor was aerated with regular air (0.03% CO2) and the experimental reactor was aerated with air containing 1% CO2. Ammonium and NO3- were measured online to determine the nitrification rates. Samples for solids and chemical oxygen demand (COD) determination were collected to evaluate the system performance. Supplying CO2 to the experimental reactor throughout the entire react cycle resulted in proliferation of filamentous bacteria, poor settling, and washout of the biomass. However, nitrate formation rates in the experimental reactor were 3 times higher than the control before washout occurred. In a subsequent experiment, CO2 was supplied to the experimental reactor only during the last 5 hours of the cycle, resulting in excellent settling and nitrification rates 6 times higher than in the control. A confirmatory experiment was conducted that lowered the SRT from 8 days to 6, 4, and 2 days. Nitrate formation rates were up to 12 times higher in the experimental reactor compared to the control, with an average of 4 times higher. Additionally, the sludge volume index (SVI) suggested a positive impact of CO2 on settling performance. No impact of CO2 on COD removal was observed. The results obtained suggest a positive effect of CO2 on the nitrate formation and settling performance in the activated sludge system, indicating that nitrification can be achieved at low SRTs which might optimize WWTPs capacity.

No description available.

A positive relationship between foliar copper levels and fruit firmness in apricots was established in the late 1980’s. A review of the literature and discussions with both national and international researchers led to research upon the influence of foliar applied copper on fruit quality. Studies were initiated using cherries, which in addition to being a soft fruit also suffer from rain induced fruit cracking. Results of initial studies suggested that the treatment should be applied to other fruit crops to determine if similar responses occur in these. To this end two further experiments were conducted on apples. As a result of this research, a practical means of reducing rain induced damage to cherries was developed. This finding has major ramifications for all cherry growing regions of the world. / Doctor of Philosophy (PhD)

No description available.

Le 2-éthylhexyl nitrate (2-EHN) est incorporé en quantité significative au gazole afin d'augmenter son indice de cétane. Ce composé est produit à raison de 100 000 tonnes par an, principalement en France. Les risques liés à son utilisation sont cependant mal connus car en cas de contamination de l'environnement, on ne sait pas s'il est biodégradable. Cette étude avait pour but (i) d'évaluer la capacité de biodégradation du 2-EHN par des bactéries sélectionnées, (ii) d'élucider la voie de dégradation, et (iii) d'identifier les enzymes impliquées. Les tests de biodégradation prenant en compte le caractère toxique et hydrophobe du substrat on été mis au point dans un premier temps. A l'aide de ces tests qui reposent sur la mise en oeuvre de cultures biphasiques, nous avons montré que plusieurs souches de Mycobacterium austroafricanum étaient capables de dégrader le 2-EHN. La souche la plus performante (IFP 2173), résistant à des concentrations de 2-EHN de 6 g.L-1, a été choisie pour étudier la voie de dégradation. Sur la base de bilans carbone et d'analyse du milieu de culture par chromatographie gazeuse (CG), j'ai découvert que la dégradation du 2-EHN était incomplète et donnait lieu à l'accumulation d'un métabolite. Ce métabolite a été identifié comme étant la β-méthyl-γ-butyrolactone par des analyses de CG-MS et LC-MS/MS. La structure de cette lactone indiquait que le 2-EHN était dégradé selon une voie enzymatique impliquant l'hydroxylation du groupement méthyle de la chaîne carbonée principale, son oxydation en aldéhyde et acide, et enfin un cycle de β-oxydation. <br>Dans un deuxième temps, les enzymes impliquées dans la voie de dégradation du 2-EHN ont été recherchées par une approche protéomique. Des analyses par électrophorèse bidimensionnelle ont mis en évidence qu'en présence de 2-EHN, la souche IFP 2173 déclenche la synthèse d'une panoplie d'enzymes spécialisées dans le métabolisme des acides gras, comme les enzymes de la β-oxydation, des alcool et aldéhyde déshydrogénases. Une analyse exhaustive du protéome de la souche IFP 2173 a permis d'identifier par LC-MS/MS plus de 200 protéines induites sur 2-EHN, notamment un cytochrome P450 de type alcane monooxygénase (CYP153). En outre, j'ai également identifié et cloné les gènes codant deux alcanes hydroxylases transmembranaires de types AlkB, qui n'ont pas été détectées par l'approche protéomique. Ainsi, la souche IFP 2173 possède trois alcane hydroxylases susceptibles de catalyser l'attaque initiale du 2-EHN. Pour déterminer laquelle de ces trois monooxygénases était responsable de cette réaction, leur gène respectif a été cloné dans des plasmides conçus pour l'expression soit chez E. coli, soit chez M. smegmatis mc². Nos résultats préliminaires montrent que dans certains cas les protéines recombinantes sont bien synthétisées. Ces constructions seront employées pour étudier l'activité des trois hydroxylases de IFP 2173 vis-à-vis des alcanes et du 2-EHN en particulier.

<p>Denna rapport är en sammanställning av de 100 undersökta enskilda brunnarna i Landskrona kommun vid årsskiftet 05/06. Det utfördes analyser på mikrobiologisk-, nitrat-, nitrit- och även kemiska bekämpningsmedelspåverkan. Syftet med denna rapport är att bearbeta och presentera analysresultaten av de 100 enskilda brunnarna i Landskrona kommun och försöka dra slutsatser kring dessa. Alla analysresultaten sammanställdes i tabeller och så småningom kundes vissa slutsatser dras kring varför resultatet såg ut som det gjorde. Resultatet visade att endast åtta av de 100 brunnarna var otjänliga gällande mikrobiologisk påverkan. Denna parameter är väldigt varierande beroende mycket på yttre omständigheter men det kan ge en indikation på att brunnen inte är tillräckligt tät och därför kan ytvatten tränga in i brunnen. När det gäller nitritpåverkan blev bara en brunn otjänlig. Men när det gällde nitrat var det istället 17 % av brunnarna som visade sig vara otjänliga. Detta är ändå ett relativt bra resultat beroende på hur landskapet ser ut i Skåne med stor påverkan från enskilda avlopp, jordbruk och gödsling. Sist men inte minst analyserades kemiska bekämpningsmedel och gav ett oroande resultat. Hela 35 % av brunnarna var otjänliga pga. kemiska bekämpningsmedel. Detta resultat är inget ovanligt utan kan genom danska undersökningar bara bekräftas. Kemiska bekämpningsmedel kan sprida sig långa sträckor och inte bara vid den plats där ämnena använts eller spillts. De slutsatser som kan dras genom denna undersökning är att grävda brunnar i ytliga jordlager löper störst risk att i framtiden bli otjänliga då dessa utsetts för störst påverkan av föroreningar och ytvatten. Brunnar placerade på gårdsplan är speciellt utsatta och är starkt påverkade av både mikroorganismer och kemiska bekämpningsmedel. När det gäller kemiska bekämpningsmedel är resultaten från Landskrona liknande de från både Danmark och övriga Skåne.</p> / <p>The problem with bad drinking water in wells are a wide problem in an landscape such as Skåne. The purpose of this report is to work up all the data from the different analysis regarding drinking water quality from wells in Landskrona municipality. The parameters that were analysed were microorganisms, the content of nitrate and nitrite and also the concentration of pesticides. Many reports in the field of the subject were collected to get a good picture and a better knowledge of the different problems that lie ahead. This resulted in various conclusions but some of the conclusions was confirmed from other examinations. That wells in the ground are more exposed than wells in mountain. The concentration of pesticides were very high in many of the wells wich shows that this will be a great problem for us to deal with in the future. Examinations in both Denmark and remaining parts of Sweden also show high concentration of pesticides. This only confirm that the problem isn’t just a local here in the municipality.</p>

<p>Because of the impact on human health and sustainable livelihood, the topic of drinking water and sanitation facilities is becoming a seriously discussed issue among international organizations as well as developing agencies in industrialized countries. The importance of water and sanitation management initialized this master thesis.</p><p> </p><p>The aim of the project is to do an assessment of the drinking water quality as well as the sanitation situation in the village Condrita in the Republic of Moldova. This was done by studying the existing water and sanitation facilities, sampling the water, evaluating the reason for the poor water quality and mapping the current situation using ArcGIS. Furthermore, technologies for improving the drinking water and sanitation facilities are suggested.</p><p> </p><p>The work was carried out by doing a literature study on how water sources and sanitation facilities should be constructed in order to ensure people’s health and to meet their needs. Geographic coordinates and water samples were collected from twenty-two public wells and springs. Interviews on the water situation and sanitation facilities were performed. Furthermore, water samples were analysed with respect to nitrate, turbidity, electrical conductivity and coliform bacteria amongst others. Pesticide contamination was also taken into consideration when one of the wells was analysed. Water sources were classified as improved or unimproved according to definitions by WHOSIS. Moreover, the DRASTIC vulnerability model was used to evaluate the groundwater susceptibility to contaminants.</p><p> </p><p>In general, the water quality in the study area was poor and measured values of the analyzed parameters exceeded international or Moldovan standards for nitrate, hardness, electrical conductivity and total coliform bacteria. Four wells were contaminated with <em>E. coli</em> bacteria. Furthermore, turbidity measurements exceeded Moldovan standards in seven out of twenty-two water sources. No pesticide contamination was detected. Sampled water from the densely populated parts of the village as well as unimproved water sources proved to be of poorer quality. Map results showed that a majority of the groundwater within the study area was subject to a moderate or high risk of becoming contaminated. The current sanitation situation is that most families use simple pit latrines, which are placed far away from the dwelling-houses. Digging a new toilet when the existing one is full is a common practice in Condrita. Hand-washing facilities are seldom placed in proximity to the toilets.</p><p> </p><p>Pit latrines are believed to be the most important source of groundwater contamination in the study area. Other sources are agricultural activities and poor practice when abstracting water from the wells. A feasible solution to improve both the drinking water quality and the sanitation situation would be to install ecosan toilets. Improvements of the well’s features that are suggested include construction of an apron slab as well as proper lids for covering the well.</p>