The Effects of Artificial Destratification on the Water Quality and Microbial Populations of Hyrum Reservoir

Artificial destratification is being increasingly used in attempts to improve water quality and control eutrophication. Most of the artificial destratification efforts are being conducted by public water supply utilities in efforts to improve reservoir water quality for culinary purposes. At present, artificial destratification is being conducted without a complete understanding of the process or its effects on the reservoir. Whether or not artificial destratification can control algal growth and other microbial processes is a controversial question. The effect of artificial destratification on the microbial flora must be understood if it is to be used effectively as a management tool in the control of water quality. In recent years a blue-green algal bloom has developed during the summer in Hyrum Reservoir. The massive bloom of Aphanizomenon jlos-aquae presents esthetic problems to those using the reservoir for recreational purposes. These esthetic problems have reduced the use of the reservoir for swimming, water skiing, and fishing. It is believed that artificial de stratification, or the destruction of natural stratification obtained through diffused-air aeration, will improve the water quality of the reservoir

Iron Dynamics in a Gas-Water-Sediment Microcosm

Iron dynamics in eutrophic systems were studied in the laboratory utilizing gas-water-Sediment phase sealed microcosms. Sediments from Hyrum Reservoir (2.4 percent iron by weight) were placed in the dark to simulate the hypolimnetic regions of a eutrophic impoundment. Iron both chemically and physically was readily available to microorganisms of the aqueous phase because iron in these systems was soluble. In the light microcosms, which simulated shallow littoral regions of eutrophic impoundments, iron was found in higher aqueous phase concentrations than was predicted chemically and physically; this was rationalized through biological mechanisms. The experiment was conducted in two phases: Phase I lasted 189 days (0 and 0.300 mg NO3–N/1 inputs) and phase II lated 175 days (10mg NO3-N/1 imput). Average light microcosm effluent iron concentrations increased from 0.092 mg FE/1 (Phase I) to 0.246 mg Fe/1 (Phase II) given higher inorganic nitrogen inputs. In Phase II, when nitrogen input into the microcosms ceased (nitrogen perturbations, day 115), aqueous phase iron concentrations in the dark microcosms increased dramatically (0.011 to 0.624 mg Fe/1)

Water Quality Analysis Laboratory Procedures Syllabus

Introduction: The 1976 edition of Methods of Chemical Analysis of Water and Wastes describes chemical analytical procedures to be sued in Water Quality Office (WQO) laboratoires. The methods were chose through the combined efforts of the Regional Analytical Quality Control (AQC) Coordinators, Laboratory Quality Control Officers, and other senior chemicsts in both federal and state laboratories. Method selection was based on the following criteria: 1. The method should measure the desired constitutent with precision and accuracy suffiecient to meet the data needs of WQO in the presence of the interferences normally encountered in polluted waters. 2. The procedures should utilize the equipment and skillso normally available in the typical water pollution control laboratory. 3. The selected methods are in use in many laboraties or have been sufficiently tested to establish their validity. 4. The mthods should be sufficiently rapid to permit routine use for the examination of a large number of samples. Except where noted under scope and Application for each constituent, the methods can be used for the measurement of the indicated constituent in both water and wastewaters and in oboth saline and fresh water samples. Instrumental methods have been selected in preference to manual procedures because of the improved speed, precision, and accuracy. Procedures for the Technicon AutoAnalyzer have been included for laboratories having this equipment available. Precision and accuracy statements have been derived from interlaboratory studies conducted by the Methods and Performance Activity, Analytical Quality Control Laboratory, WQO; the American Society for Testing Materials; or the Analytical Reference Service of the Public Health Service, DHEW. Specific instructions for the handling and preservation of samples cannot be given because of the wide variability in types of samples and local sampling situations. However, certain general principles should be followed. Wherever possible, the sampling program should be designed to provide for the shortest possible interval between sample collection and analysis. Positive steps should be taken to maintain both the concentration and the physical state of the constituents to be measureed

Review paper: Evaluation of Techniques for Algae Removal from Wastewater Stabilization Ponds

Introduction: Approximately 90 percent of the wastewater lagoons in the United States are located in small communities of 5,000 people or less. These communities, many with an average daily wastewater flow of only 175,000 - 200,000 gallons, do not have the resources to keep man at the lagoon sites throughout the day (38). A high degree of technical knowhow is usually lacking in these communities. Often only periodic inspection or maintenance is carried out by the general municipal work force. Therefore, the development of a relatively inexpensive method that does not require sophisticated and constant operation or extensive maintenance is needed to polish these effluents. Most regulatory agencies are adopting more stringent water quality standards, enforcement of which will necessitate changes in present treatment methods and the philosophy of wastewater treatment. Small communities utilizing stabilization ponds will be affected most drastically by new standards. Because most communities utilizing ponds are relatively small and installed ponds primariliy to avoid operating costs, it is unlikely that modifications requiring significant increases in operation will be acceptable. Therefore, the most sophisticated alternatives for upgrading treatment must be excluded from a practicable solution to solids removal from stabilization pond effluent

The Giardia lamblia vsp gene repertoire: characteristics, genomic organization, and evolution

BACKGROUND:Giardia lamblia trophozoites colonize the intestines of susceptible mammals and cause diarrhea, which can be prolonged despite an intestinal immune response. The variable expression of the variant-specific surface protein (VSP) genes may contribute to this prolonged infection. Only one is expressed at a time, and switching expression from one gene to another occurs by an epigenetic mechanism.RESULTS:The WB Giardia isolate has been sequenced at 10x coverage and assembled into 306 contigs as large as 870 kb in size. We have used this assembly to evaluate the genomic organization and evolution of the vsp repertoire. We have identified 228 complete and 75 partial vsp gene sequences for an estimated repertoire of 270 to 303, making up about 4% of the genome. The vsp gene diversity includes 30 genes containing tandem repeats, and 14 vsp pairs of identical genes present in either head to head or tail to tail configurations (designated as inverted pairs), where the two genes are separated by 2 to 4 kb of non-coding DNA. Interestingly, over half the total vsp repertoire is present in the form of linear gene arrays that can contain up to 10 vsp gene members. Lastly, evidence for recombination within and across minor clades of vsp genes is provided.CONCLUSIONS:The data we present here is the first comprehensive analysis of the vsp gene family from the Genotype A1 WB isolate with an emphasis on vsp characterization, function, evolution and contributions to pathogenesis of this important pathogen.This item is part of the UA Faculty Publications collection. For more information this item or other items in the UA Campus Repository, contact the University of Arizona Libraries at [email protected]

Nutrient Dynamics and Gas Production in Aquatic Ecosystems: The Effects and Utilization of Mercury and Nitrogen in Sediment-Water Microcosms

Sixteen sediment-water microcosms designed to allow complete gas, liquid, and solid mass balances of gases, nutrients, and mercury were studies under dark conditions or varying light intensity for a period of 189 days. Results indicated that the microcosm technique is a very sensitive method of analyzing microbial dynamics in sediment water systems. Gas quantity and composition changes were easy to monitor and were especially sensitive to light and nutrient variations. Nitrogen fixation occurred in all lighted systems (blue-green algae nitrogen fixers, Anabaena, and others) and was adequate to insure that no nitrogen limitation occurred even though nitrogen limitation was imposed on the system. Sediments apparently did not act as a significant source of nitrogen. Iron and phosphorus were in excess and as such were closely linked as would be predicted on the basis of chemical equilibria. Non-equilibrium chemical behavior of such elements would apparently result only when appreciable amounts of the compound or element is utilized in growth

Exposure-Dependent Control of Malaria-Induced Inflammation in Children

In malaria-naïve individuals, Plasmodium falciparum infection results in high levels of parasite-infected red blood cells (iRBCs) that trigger systemic inflammation and fever. Conversely, individuals in endemic areas who are repeatedly infected are often asymptomatic and have low levels of iRBCs, even young children. We hypothesized that febrile malaria alters the immune system such that P. falciparum re-exposure results in reduced production of pro-inflammatory cytokines/chemokines and enhanced anti-parasite effector responses compared to responses induced before malaria. To test this hypothesis we used a systems biology approach to analyze PBMCs sampled from healthy children before the six-month malaria season and the same children seven days after treatment of their first febrile malaria episode of the ensuing season. PBMCs were stimulated with iRBC in vitro and various immune parameters were measured. Before the malaria season, children's immune cells responded to iRBCs by producing pro-inflammatory mediators such as IL-1β, IL-6 and IL-8. Following malaria there was a marked shift in the response to iRBCs with the same children's immune cells producing lower levels of pro-inflammatory cytokines and higher levels of anti-inflammatory cytokines (IL-10, TGF-β). In addition, molecules involved in phagocytosis and activation of adaptive immunity were upregulated after malaria as compared to before. This shift was accompanied by an increase in P. falciparum-specific CD4+Foxp3- T cells that co-produce IL-10, IFN-γ and TNF; however, after the subsequent six-month dry season, a period of markedly reduced malaria transmission, P. falciparum-inducible IL-10 production remained partially upregulated only in children with persistent asymptomatic infections. These findings suggest that in the face of P. falciparum re-exposure, children acquire exposure-dependent P. falciparum-specific immunoregulatory responses that dampen pathogenic inflammation while enhancing anti-parasite effector mechanisms. These data provide mechanistic insight into the observation that P. falciparum-infected children in endemic areas are often afebrile and tend to control parasite replication

Malaria-associated atypical memory B cells exhibit markedly reduced B cell receptor signaling and effector function

Protective antibodies in Plasmodium falciparum malaria are only acquired after years of repeated infections. Chronic malaria exposure is associated with a large increase in atypical memory B cells (MBCs) that resemble B cells expanded in a variety of persistent viral infections. Understanding the function of atypical MBCs and their relationship to classical MBCs will be critical to developing effective vaccines for malaria and other chronic infections. We show that VH gene repertoires and somatic hypermutation rates of atypical and classical MBCs are indistinguishable indicating a common developmental history. Atypical MBCs express an array of inhibitory receptors and B cell receptor (BCR) signaling is stunted in atypical MBCs resulting in impaired B cell responses including proliferation, cytokine production and antibody secretion. Thus, in response to chronic malaria exposure, atypical MBCs appear to differentiate from classical MBCs becoming refractory to BCR-mediated activation and potentially interfering with the acquisition of malaria immunity. DOI: http://dx.doi.org/10.7554/eLife.07218.00

Treatment of Chronic Asymptomatic Plasmodium falciparum Infection Does Not Increase the Risk of Clinical Malaria Upon Reinfection.

: Chronic asymptomatic Plasmodium falciparum infections are common in endemic areas and are thought to contribute to the maintenance of malaria immunity. Whether treatment of these infections increases the subsequent risk of clinical episodes of malaria is unclear. : In a 3-year study in Mali, asymptomatic individuals with or without P. falciparum infection at the end of the 6-month dry season were identified by polymerase chain reaction (PCR), and clinical malaria risk was compared during the ensuing 6-month malaria transmission season. At the end of the second dry season, 3 groups of asymptomatic children were identified: (1) children infected with P. falciparum as detected by rapid diagnostic testing (RDT) who were treated with antimalarials (n = 104), (2) RDT-negative children whose untreated P. falciparum infections were detected retrospectively by PCR (n = 55), and (3) uninfected children (RDT/PCR negative) (n = 434). Clinical malaria risk during 2 subsequent malaria seasons was compared. Plasmodium falciparum-specific antibody kinetics during the dry season were compared in children who did or did not harbor asymptomatic P. falciparum infections. : Chronic asymptomatic P. falciparum infection predicted decreased clinical malaria risk during the subsequent malaria season(s); treatment of these infections did not alter this reduced risk. Plasmodium falciparum-specific antibodies declined similarly in children who did or did not harbor chronic asymptomatic P. falciparum infection during the dry season. : These findings challenge the notion that chronic asymptomatic P. falciparum infection maintains malaria immunity and suggest that mass drug administration during the dry season should not increase the subsequent risk of clinical malaria.<br/