Effects of Environmental Oxygen Content and Dissolved Oxygen on the Surface Tension and Viscosity of Liquid Nickel

NASA Astrophysics Data System (ADS)

SanSoucie, M. P.; Rogers, J. R.; Kumar, V.; Rodriguez, J.; Xiao, X.; Matson, D. M.

2016-07-01

The NASA Marshall Space Flight Center's electrostatic levitation (ESL) laboratory has recently added an oxygen partial pressure controller. This system allows the oxygen partial pressure within the vacuum chamber to be measured and controlled in the range from approximately 10^{-28} {to} 10^{-9} bar, while in a vacuum atmosphere. The oxygen control system installed in the ESL laboratory's main chamber consists of an oxygen sensor, oxygen pump, and a control unit. The sensor is a potentiometric device that determines the difference in oxygen activity in two gas compartments (inside the chamber and the air outside of the chamber) separated by an electrolyte. The pump utilizes coulometric titration to either add or remove oxygen. The system is controlled by a desktop control unit, which can also be accessed via a computer. The controller performs temperature control for the sensor and pump, has a PID-based current loop and a control algorithm. Oxygen partial pressure has been shown to play a significant role in the surface tension of liquid metals. Oxide films or dissolved oxygen may lead to significant changes in surface tension. The effects on surface tension and viscosity by oxygen partial pressure in the surrounding environment and the melt dissolved oxygen content will be evaluated, and the results will be presented. The surface tension and viscosity will be measured at several different oxygen partial pressures while the sample is undercooled. Surface tension and viscosity will be measured using the oscillating droplet method.

EFFECTS OF SUNLIGHT ON CARBOXYL CONTENT OF DISSOLVED ORGANIC MATTER IN THE SATILLA RIVER OF GEORGIA, UNITED STATES

EPA Science Inventory

A study examined the effect of sunlight-initiated photo-degradation of dissolved organic matter (DOM) on its carboxyl content, and the role of oxygen and iron in this process. Solar-simulated irradiations were performed on 0.2-mm filtered water samples collected from the highly c...

Measuring Flow Rate in Crystalline Bedrock Wells Using the Dissolved Oxygen Alteration Method.

PubMed

Vitale, Sarah A; Robbins, Gary A

2017-07-01

Determination of vertical flow rates in a fractured bedrock well can aid in planning and implementing hydraulic tests, water quality sampling, and improving interpretations of water quality data. Although flowmeters are highly accurate in flow rate measurement, the high cost and logistics may be limiting. In this study the dissolved oxygen alteration method (DOAM) is expanded upon as a low-cost alternative to determine vertical flow rates in crystalline bedrock wells. The method entails altering the dissolved oxygen content in the wellbore through bubbler aeration, and monitoring the vertical advective movement of the dissolved oxygen over time. Measurements were taken for upward and downward flows, and under ambient and pumping conditions. Vertical flow rates from 0.06 to 2.30 Lpm were measured. To validate the method, flow rates determined with the DOAM were compared to pump discharge rates and found to be in agreement within 2.5%. © 2017, National Ground Water Association.

Cavitating Jet Method and System for Oxygenation of Liquids

NASA Technical Reports Server (NTRS)

Chahine, Georges L.

2012-01-01

Reclamation and re-use of water is critical for space-based life support systems. A number of functions must be performed by any such system including removal of various contaminants and oxygenation. For long-duration space missions, this must be done with a compact, reliable system that requires little or no use of expendables and minimal power. DynaJets cavitating jets can oxidize selected organic compounds with much greater energy efficiency than ultrasonic devices typically used in sonochemistry. The focus of this work was to develop cavitating jets to simultaneously accomplish the functions of oxygenation and removal of contaminants of importance to space-structured water reclamation systems. The innovation is a method to increase the concentration of dissolved oxygen or other gasses in a liquid. It utilizes a particular form of novel cavitating jet operating at low to moderate pressures to achieve a high-efficiency means of transporting and mixing the gas into the liquid. When such a jet is utilized to simultaneously oxygenate the liquid and to oxidize organic compounds within the liquid, such as those in waste water, the rates of contaminant removal are increased. The invention is directed toward an increase in the dissolved gas content of a liquid, in general, and the dissolved oxygen content of a liquid in particular.

Effect of Growth Conditions and Trehalose Content on Cryotolerance of Bakers' Yeast in Frozen Doughs

PubMed Central

Gélinas, Pierre; Fiset, Gisèle; LeDuy, Anh; Goulet, Jacques

1989-01-01

The cryotolerance in frozen doughs and in water suspensions of bakers' yeast (Saccharomyces cerevisiae) previously grown under various industrial conditions was evaluated on a laboratory scale. Fed-batch cultures were very superior to batch cultures, and strong aeration enhanced cryoresistance in both cases for freezing rates of 1 to 56°C min−1. Loss of cell viability in frozen dough or water was related to the duration of the dissolved-oxygen deficit during fed-batch growth. Strongly aerobic fed-batch cultures grown at a reduced average specific rate (μ = 0.088 h−1 compared with 0.117 h−1) also showed greater trehalose synthesis and improved frozen-dough stability. Insufficient aeration (dissolved-oxygen deficit) and lower growth temperature (20°C instead of 30°C) decreased both fed-batch-grown yeast cryoresistance and trehalose content. Although trehalose had a cryoprotective effect in S. cerevisiae, its effect was neutralized by even a momentary lack of excess dissolved oxygen in the fed-batch growth medium. PMID:16348024

Water-quality conditions in the New River, Imperial County, California

USGS Publications Warehouse

Setmire, James G.

1979-01-01

The New River, when entering the United States at Calexico, Calif., often contains materials which have the appearance of industrial and domestic wastes. Passage of some of these materials is recognized by a sudden increase in turbidity over background levels and the presence of white particulate matter. Water samples taken during these events are usually extremely high in organic content. During a 4-day reconnaissance of water quality in May 1977, white-to-brown extremely turbid water crossed the border on three occasions. On one of these occasions , the water was intensively sampled. The total organic-carbon concentration ranged from 80 to 161 milligrams per liter (mg/l); dissolved organic carbon ranged from 34 to 42 mg/l, and the chemical oxygen demand was as high as 510 mg/l. River profiles showed a dissolved-oxygen sag, with the length of the zone of depressed dissolved-oxygen concentrations varying seasonally. During the summer months, dissolved-oxygen concentrations in the river were lower and the zone of depressed dissolved-oxygen concentrations was longer. The largest increases in dissolved-oxygen concentration from reaeration occurred at the three drop structures and the rock weir near Seeley. The effects of oxygen demanding materials crossing the border extended as far as Highway 80, 19.5 miles downstream from the international boundary at Calexico. Fish kills and anaerobic conditions were also detected as far as Highway 80. Standard bacteria indicator tests for fecal contamination showed a very high health-hazard potential near the border. (Woodard-USGS)

Establishment of a total liquid ventilation system using saline-based oxygen micro/nano-bubble dispersions in rats.

PubMed

Kakiuchi, Kenta; Matsuda, Kenichi; Harii, Norikazu; Sou, Keitaro; Aoki, Junko; Takeoka, Shinji

2015-09-01

Micro/nano-bubbles are practical nanomaterials designed to increase the gas content in liquids. We attempted to use oxygen micro/nano-bubble dispersions as an oxygen-rich liquid as a means for total liquid ventilation. To determine the oxygen content in the bubble dispersion, a new method based on a spectrophotometric change between oxy- and deoxy-hemoglobin was established. The oxygen micro/nano-bubble dispersion was supplied to an experimental total ventilation liquid in anesthetic rats. Though the amount of dissolving oxygen was as low as 6 mg/L in physiological saline, the oxygen content in the oxygen micro/nano-bubble dispersion was increased to 45 mg/L. The positive correlation between the oxygen content and the life-saving time under liquid ventilation clearly indicates that the life-saving time is prolonged by increasing the oxygen content in the oxygen micro/nano-bubble dispersion. This is the first report indicating that the oxygen micro/nano-bubbles containing a sufficient amount of oxygen are useful in producing oxygen-rich liquid for the process of liquid ventilation.

Water-quality parameters and benthic algal communities at selected streams in Minnesota, August 2000 - Study design, methods and data

USGS Publications Warehouse

Lee, K.E.

2002-01-01

This report describes the study design, sampling methods, and summarizes the physical, chemical, and benthic algal data for a component of the multiagency study that was designed to document diurnal water-quality measurements (specific conductance, pH, water temperature, and dissolved oxygen), benthic algal community composition and chlorophyll-a content, and primary productivity at 12 stream sites on 6 streams in Minnesota during August 2000. Specific conductance, pH, water temperature, dissolved oxygen concentrations and percent dissolved oxygen saturation measurements were made with submersible data recorders at 30 minute intervals for a period of 3-6 days during August 2000. Benthic algae collected from wood and rock substrate were identified and enumerated. Biovolume (volume of algal cells per unit area), density (number of cells per unit area), and chlorophyll-a content from benthic algae were determined. These data can be used as part of the multiagency study to develop an understanding of the relations among nutrient concentrations, algal abundance, algal community composition, and primary production and respiration processes in rivers of differing ecoregions in Minnesota.

Impact of oxygen dissolved at bottling and transmitted through closures on the composition and sensory properties of a Sauvignon Blanc wine during bottle storage.

PubMed

Lopes, Paulo; Silva, Maria A; Pons, Alexandre; Tominaga, Takatoshi; Lavigne, Valérie; Saucier, Cédric; Darriet, Philippe; Teissedre, Pierre-Louis; Dubourdieu, Denis

2009-11-11

This work outlines the results from an investigation to determine the effect of the oxygen dissolved at bottling and the specific oxygen barrier properties of commercially available closures on the composition, color and sensory properties of a Bordeaux Sauvignon Blanc wine during two years of storage. The importance of oxygen for wine development after bottling was also assessed using an airtight bottle ampule. Wines were assessed for the antioxidants (SO(2) and ascorbic acid), varietal thiols (4-mercapto-4-methylpentan-2-one, 3-mercaptohexan-1-ol), hydrogen sulfide and sotolon content, and color throughout 24 months of storage. In addition, the aroma and palate properties of wines were also assessed. The combination of oxygen dissolved at bottling and the oxygen transferred through closures has a significant effect on Sauvignon Blanc development after bottling. Wines highly exposed to oxygen at bottling and those sealed with a synthetic, Nomacorc classic closure, highly permeable to oxygen, were relatively oxidized in aroma, brown in color, and low in antioxidants and volatile compounds compared to wines sealed with other closures. Conversely, wines sealed under more airtight conditions, bottle ampule and screw cap Saran-tin, have the slowest rate of browning, and displayed the greatest contents of antioxidants and varietal thiols, but also high levels of H(2)S, which were responsible for the reduced dominating character found in these wines, while wines sealed with cork stoppers and screw cap Saranex presented negligible reduced and oxidized characters.

Addition of ammonia and/or oxygen to an ionic liquid for delignification of miscanthus.

PubMed

Rodríguez, Héctor; Padmanabhan, Sasisanker; Poon, Geoffrey; Prausnitz, John M

2011-09-01

Ammonia and/or oxygen were used to enhance the delignification of miscanthus dissolved in 1-ethyl-3-methylimidazolium acetate at 140°C. After dissolution of the gas at 9 bar, water was added as antisolvent to regenerate the dissolved biomass. In a next step, an acetone/water mixture was used to remove carbohydrate-free lignin from the regenerated biomass. The lignin content in the final product was around 10%, much lower than the ca. 23% lignin content of the raw dry miscanthus. This lignin reduction is achieved without diminution of cellulose or of total carbohydrates recovered, relative to the recovery achieved with the ionic liquid pretreatment in contact with air or nitrogen. Copyright © 2011 Elsevier Ltd. All rights reserved.

Selected papers in the hydrologic sciences 1984; July 1984

USGS Publications Warehouse

Meyer, Eric L.

1984-01-01

The rapid, accurate measurement of the oxygen content of soil gas in the unsaturated zone or dissolved oxygen in soil water in the saturated zone can be useful in wetland vegetation studies. A method has been devised and tested in the Great Dismal Swamp, a wetland with fine silt-clay and organic soils, that appears to provide good results. A 60-milliliter sample of soil gas or water is withdrawn from permanently installed chambers at various depths in the soil profile. The oxygen concentration of air samples is measured with a specially constructed analyzer cell fitted to the polarographic oxygen electrode of a portable oxygen meter. The dissolved oxygen concentration of water samples is measured directly with the oxygen electrode while stirring the sample in a 32-milliliter glass bottle with a portable magnetic stirrer. Field tests with duplicate chamber installations showed that consistent results are obtained for soil gas and water.

Water Quality: A Field-Based Quality Testing Program for Middle Schools and High Schools.

ERIC Educational Resources Information Center

Massachusetts State Water Resources Authority, Boston.

This manual contains background information, lesson ideas, procedures, data collection and reporting forms, suggestions for interpreting results, and extension activities to complement a water quality field testing program. Information on testing water temperature, water pH, dissolved oxygen content, biochemical oxygen demand, nitrates, total…

Simultaneous nitrification, denitrification, and phosphorus removal in single-tank low-dissolved-oxygen systems under cyclic aeration.

PubMed

Ju, Lu-Kwang; Huang, Lin; Trivedi, Hiren

2007-08-01

Simultaneous nitrification and denitrification (SND or SNdN) may occur at low dissolved oxygen concentrations. In this study, bench-scale (approximately 6 L) bioreactors treating a continuous feed of synthetic wastewater were used to evaluate the effects of solids retention time and low dissolved oxygen concentration, under cyclic aeration, on the removal of organics, nitrogen, and phosphorus. The cyclic aeration was carried out with repeated cycles of 1 hour at a higher dissolved oxygen concentration (HDO) and 30 minutes at a lower (or zero) dissolved oxygen concentration (LDO). Compared with aeration at constant dissolved oxygen concentrations, the cyclic aeration, when operated with proper combinations of HDO and LDO, produced better-settling sludge and more complete nitrogen and phosphorus removal. For nitrogen removal, the advantage resulted from the more readily available nitrate and nitrite (generated by nitrification during the HDO period) for denitrification (during the LDO period). For phosphorus removal, the advantage of cyclic aeration came from the development of a higher population of polyphosphate-accumulating organisms, as indicated by the higher phosphorus contents in the sludge solids of the cyclically aerated systems. Nitrite shunt was also observed to occur in the LDO systems. Higher ratios of nitrite to nitrate were found in the systems of lower HDO (and, to less dependency, higher LDO), suggesting that the nitrite shunt took place mainly because of the disrupted nitrification at lower HDO. The study results indicated that the HDO used should be kept reasonably high (approximately 0.8 mg/L) or the HDO period prolonged, to promote adequate nitrification, and the LDO kept low (< or =0.2 mg/L), to achieve more complete denitrification and higher phosphorus removal. The above findings in the laboratory systems find strong support from the results obtained in full-scale plant implementation. Two plant case studies using the cyclic low-dissolved-oxygen aeration for creating and maintaining SND are also presented.

Limited denitrification in glacial deposit aquifers having thick unsaturated zones (Long Island, USA)

NASA Astrophysics Data System (ADS)

Young, Caitlin; Kroeger, Kevin D.; Hanson, Gilbert

2013-12-01

The goal of this study was to demonstrate how the extent of denitrification, which is indirectly related to dissolved organ carbon and directly related to oxygen concentrations, can also be linked to unsaturated-zone thickness, a mappable aquifer property. Groundwater from public supply and monitoring wells in Northport on Long Island, New York state (USA), were analyzed for denitrification reaction progress using dissolved N2/Ar concentrations by membrane inlet mass spectrometry. This technique allows for discernment of small amounts of excess N2, attributable to denitrification. Results show an average 15 % of total nitrogen in the system was denitrified, significantly lower than model predictions of 35 % denitrification. The minimal denitrification is due to low dissolved organic carbon (29.3-41.1 μmol L-1) and high dissolved oxygen concentrations (58-100 % oxygen saturation) in glacial sediments with minimal solid-phase electron donors to drive denitrification. A mechanism is proposed that combines two known processes for aquifer re-aeration in unconsolidated sands with thick (>10 m) unsaturated zones. First, advective flux provides 50 % freshening of pore space oxygen in the upper 2 m due to barometric pressure changes. Then, oxygen diffusion across the water-table boundary occurs due to high volumetric air content in the unsaturated-zone catchment area.

CADDIS Volume 2. Sources, Stressors and Responses: Dissolved Oxygen

EPA Pesticide Factsheets

Introduction to the dissolved oxygen module, when to list dissolved oxygen as a candidate cause, ways to measure dissolved oxygen, simple and detailed conceptual model diagrams for dissolved oxygen, references for the dissolved oxygen module.

Oxygen content and oxidation in frying oil.

PubMed

Totani, Nagao; Yawata, Miho; Mori, Terutoshi; Hammond, Earl G

2013-01-01

The relation between oxygen content and oxidation was investigated in frying oils. When canola oil, a canola-soybean oil blend or a trioctanoylglycerol (glycerol tricaprate) sample were heated with stirring, their dissolved oxygen content decreased abruptly at about 120°C and the carbonyl values (CV) increased gradually with heating and reached values of 6-7 at 180°C in the blended and canola oils, while the CV of trioctanoylglycerol was zero up to 150°C. Probably this abrupt decrease in oxygen content above 120°C can be attributed to the solubility of oxygen in oil rather than because of oxidative reactions. The oxygen content of oil that has been stripped of part of its oxygen, increased at temperatures between 25 and 120°C. In oils that have lost their oxygen by being heated to 180°C, standing at room temperature will slowly restore their oxygen content as the oil cools. Intermittent simple heating of oil promoted oxygen absorbance during cooling periods and standing times, and it resulted in an elevated content of polar compounds (PC). Domestic deep-frying conditions also favor the presence of oxygen in oil below 120°C and during the oil's long standing at room temperature. The oxygen content in oil was low during deep-frying, but oxidation was active at the oil/air interface of bubbles generated by foods being fried. Repeated use of oil at temperatures between 25-180°C resulted in oil with low oxygen values.

CADDIS Volume 2. Sources, Stressors and Responses: Dissolved Oxygen - Simple Conceptual Diagram

EPA Pesticide Factsheets

Introduction to the dissolved oxygen module, when to list dissolved oxygen as a candidate cause, ways to measure dissolved oxygen, simple and detailed conceptual model diagrams for dissolved oxygen, references for the dissolved oxygen module.

CADDIS Volume 2. Sources, Stressors and Responses: Dissolved Oxygen - Detailed Conceptual Diagram

EPA Pesticide Factsheets

Introduction to the dissolved oxygen module, when to list dissolved oxygen as a candidate cause, ways to measure dissolved oxygen, simple and detailed conceptual model diagrams for dissolved oxygen, references for the dissolved oxygen module.

Inventory Control.

ERIC Educational Resources Information Center

Rich, Joe, Ed.

1990-01-01

Described are the design, construction, and uses of two pieces of laboratory equipment. Included are a multipurpose meter, "Calo-pH Meter," and a device for collecting water samples for determining dissolved oxygen content. (CW)

[Influence of raising oxygen content on function of platelet concentrate during preservation].

PubMed

Zhan, Tong; Xiao, Jian-Yu; Tao, Jing; Miao, Xi-Feng; Liu, Yan-Cun; Tang, Rong-Cai

2006-08-01

To explore the influence of raising oxygen (dissolved oxygen) content on function of platelet concentrate, the platelet concentrate was prepared by a CS-3000 plus blood cell separator. Experiments were divided into 2 groups: test group and control group. After raising oxygen content in platelet plasma under sterile operation, the platelet samples of two groups were preserved in oscillator with horizontal oscillation at 22 +/- 2 degrees C. The platelet count, platelet aggregation rate, lactic acid content and CD62p expression level of platelet were detected on 0, 1, 2, 3, 4, 5 days of platelet preservation. The results showed that the platelet count and platelet aggregation rate decreased with prolongation of preserved time, while the lactic acid content and CD62p expression level of platelet increased gradually. Compared with control group, there were significant differences in aggregation rate of platelet preserved for 2-3 days, and in CD62p expression level of platelet preserved for 1-3 days, while significant difference was found in lactic acid content of platelet preserved for 1-3 days. It is concluded that raising content of oxygen in platelet plasma can provide more oxygen to compensate oxygen supply deficiency for platelet metabolism and improve the efficiency of platelet oxygenic metabolism and the quality of platelet during preservation.

Oxidation of nanoscale zero-valent iron under sufficient and limited dissolved oxygen: Influences on aggregation behaviors.

PubMed

Jiang, Danlie; Hu, Xialin; Wang, Rui; Yin, Daqiang

2015-03-01

Oxidations of nanoscale zero-valent iron (nZVI) under aerobic (dissolved oxygen≈8mgL(-1)) and anaerobic (dissolved oxygen <3mgL(-1)) conditions were simulated, and their influences on aggregation behaviors of nZVI were investigated. The two oxidation products were noted as HO-nZVI (nZVI oxidized in highly oxygenated water) and LO-nZVI (nZVI oxidized in lowly oxygenated water) respectively. The metallic iron of the oxidized nZVI was almost exhausted (Fe(0)≈8±5%), thus magnetization mainly depended on magnetite content. Since sufficient dissolved oxygen led to the much less magnetite (∼15%) in HO-nZVI than that in LO-nZVI (>90%), HO-nZVI was far less magnetic (Ms=88kAm(-1)) than LO-nZVI (Ms=365kAm(-1)). Consequently, HO-nZVI formed small agglomerates (228±10nm), while LO-nZVI tended to form chain-like aggregations (>1μm) which precipitated rapidly. Based on the EDLVO theory, we suggested that dissolved oxygen level determined aggregation morphologies by controlling the degree of oxidation and the magnitude of magnetization. Then the chain-like alignment of LO-nZVI would promote further aggregation, but the agglomerate morphology of HO-nZVI would eliminate magnetic forces and inhibit the aggregation while HO-nZVI remained magnetic. Our results indicated the fine colloidal stability of HO-nZVI, which might lead to the great mobility in the environment. Copyright © 2014 Elsevier Ltd. All rights reserved.

Modeling and validation of single-chamber microbial fuel cell cathode biofilm growth and response to oxidant gas composition

NASA Astrophysics Data System (ADS)

Ou, Shiqi; Zhao, Yi; Aaron, Douglas S.; Regan, John M.; Mench, Matthew M.

2016-10-01

This work describes experiments and computational simulations to analyze single-chamber, air-cathode microbial fuel cell (MFC) performance and cathodic limitations in terms of current generation, power output, mass transport, biomass competition, and biofilm growth. Steady-state and transient cathode models were developed and experimentally validated. Two cathode gas mixtures were used to explore oxygen transport in the cathode: the MFCs exposed to a helium-oxygen mixture (heliox) produced higher current and power output than the group of MFCs exposed to air or a nitrogen-oxygen mixture (nitrox), indicating a dependence on gas-phase transport in the cathode. Multi-substance transport, biological reactions, and electrochemical reactions in a multi-layer and multi-biomass cathode biofilm were also simulated in a transient model. The transient model described biofilm growth over 15 days while providing insight into mass transport and cathodic dissolved species concentration profiles during biofilm growth. Simulation results predict that the dissolved oxygen content and diffusion in the cathode are key parameters affecting the power output of the air-cathode MFC system, with greater oxygen content in the cathode resulting in increased power output and fully-matured biomass.

Modeling and validation of single-chamber microbial fuel cell cathode biofilm growth and response to oxidant gas composition

DOE PAGES

Ou, Shiqi; Zhao, Yi; Aaron, Douglas S.; ...

2016-08-15

This work describes experiments and computational simulations to analyze single-chamber, air-cathode microbial fuel cell (MFC) performance and cathodic limitations in terms of current generation, power output, mass transport, biomass competition, and biofilm growth. Steady-state and transient cathode models were developed and experimentally validated. Two cathode gas mixtures were used to explore oxygen transport in the cathode: the MFCs exposed to a helium-oxygen mixture (heliox) produced higher current and power output than the group of MFCs exposed to air or a nitrogen-oxygen mixture (nitrox), indicating a dependence on gas-phase transport in the cathode. Multi-substance transport, biological reactions, and electrochemical reactions inmore » a multi-layer and multi-biomass cathode biofilm were also simulated in a transient model. The transient model described biofilm growth over 15 days while providing insight into mass transport and cathodic dissolved species concentration profiles during biofilm growth. Lastly, simulation results predict that the dissolved oxygen content and diffusion in the cathode are key parameters affecting the power output of the air-cathode MFC system, with greater oxygen content in the cathode resulting in increased power output and fully-matured biomass.« less

In Situ Wetland Restoration Demonstration

DTIC Science & Technology

2016-06-01

conditions may differ from subaqueous sediment beds (e.g., moisture content, oxidation-reduction potential, temperature , dissolved oxygen ) and as such...13 3.1.1 Determine Remediation Effectiveness ...20 3.1.6 Cost Effectiveness

Measurement of dissolved oxygen during red wines tank aging with chips and micro-oxygenation.

PubMed

Nevares, I; del Alamo, M

2008-07-21

Nowadays, micro-oxygenation is a very important technique used in aging wines in order to improve their characteristics. The techniques of wine tank aging imply the use of small doses of oxygen and the addition of wood pieces of oak to the wine. Considering the low dissolved oxygen (DO) levels used by micro-oxygenation technique it is necessary to choose the appropriate measurement principle to apply the precise oxygen dosage in wine at any time, in order to assure its correct assimilation. This knowledge will allow the oenologist to control and run the wine aging correctly. This work is a thorough revision of DO measurement main technologies applied to oenology. It describes the strengths and weaknesses of each of them, and draws a comparison of their workings in wine measurement. Both, the traditional systems by electrochemical probes, and the newest photoluminescence-based probes have been used. These probes adapted to red wines ageing study are then compared. This paper also details the first results of the dissolved oxygen content evolution in red wines during a traditional and alternative tank aging. Samples have been treated by three different ageing systems: oak barrels, stainless-steel tanks with small oak wood pieces (chips) and with bigger oak pieces (staves) with low micro-oxygenation levels. French and American oak barrels manufactured by the same cooperage have been used.

Limited denitrification in glacial deposit aquifers having thick unsaturated zones (Long Island, USA)

USGS Publications Warehouse

Young, Caitlin; Kroeger, Kevin D.; Hanson, Gilbert

2013-01-01

The goal of this study was to demonstrate how the extent of denitrification, which is indirectly related to dissolved organ carbon and directly related to oxygen concentrations, can also be linked to unsaturated-zone thickness, a mappable aquifer property. Groundwater from public supply and monitoring wells in Northport on Long Island, New York state (USA), were analyzed for denitrification reaction progress using dissolved N2/Ar concentrations by membrane inlet mass spectrometry. This technique allows for discernment of small amounts of excess N2, attributable to denitrification. Results show an average 15 % of total nitrogen in the system was denitrified, significantly lower than model predictions of 35 % denitrification. The minimal denitrification is due to low dissolved organic carbon (29.3–41.1 μmol L−1) and high dissolved oxygen concentrations (58–100 % oxygen saturation) in glacial sediments with minimal solid-phase electron donors to drive denitrification. A mechanism is proposed that combines two known processes for aquifer re-aeration in unconsolidated sands with thick (>10 m) unsaturated zones. First, advective flux provides 50 % freshening of pore space oxygen in the upper 2 m due to barometric pressure changes. Then, oxygen diffusion across the water-table boundary occurs due to high volumetric air content in the unsaturated-zone catchment area.

Evaluation and use of a diffusion-controlled sampler for determining chemical and dissolved oxygen gradients at the sediment-water interface

USGS Publications Warehouse

Simon, N.S.; Kennedy, M.M.; Massoni, C.S.

1985-01-01

Field and laboratory evaluations were made of a simple, inexpensive diffusion-controlled sampler with ports on two sides at each interval which incorporates 0.2-??m polycarbonate membrane to filter samples in situ. Monovalent and divalent ions reached 90% of equilibrium between sampler contents and the external solution within 3 and 6 hours, respectively. Sediment interstitial water chemical gradients to depths of tens of centimeters were obtained within several days after placement. Gradients were consistent with those determined from interstitial water obtained by centrifugation of adjacent sediment. Ten milliliter sample volumes were collected at 1-cm intervals to determine chemical gradients and dissolved oxygen profiles at depth and at the interface between the sediment and water column. The flux of dissolved species, including oxygen, across the sediment-water interface can be assessed more accurately using this sampler than by using data collected from benthic cores. ?? 1985 Dr W. Junk Publishers.

Improvement in production and quality of gellan gum by Sphingomonas paucimobilis under high dissolved oxygen tension levels.

PubMed

Banik, R M; Santhiagu, A

2006-09-01

The effect of agitation rate and dissolved oxygen tension (DOT) on growth and gellan production by Sphingomonas paucimobilis was studied. Higher cell growth of 5.4 g l(-1) was obtained at 700 rpm but maximum gellan (15 g l(-1)) was produced at 500 rpm. DOT levels above 20% had no effect on cell growth but gellan yield was increased to 23 g l(-1 )with increase in DOT level to 100%. Higher DOT levels improved the viscosity and molecular weight of the polymer with change in acetate and glycerate content of the polymer.

The impact of oxygen on the final alcohol content of wine fermented by a mixed starter culture.

PubMed

Morales, Pilar; Rojas, Virginia; Quirós, Manuel; Gonzalez, Ramon

2015-05-01

We have developed a wine fermentation procedure that takes advantage of the metabolic features of a previously characterized Metschnikowia pulcherrima strain in order to reduce ethanol production. It involves the use of M. pulcherrima/Saccharomyces cerevisiae mixed cultures, controlled oxygenation conditions during the first 48 h of fermentation, and anaerobic conditions thereafter. The influence of different oxygenation regimes and initial inoculum composition on yeast physiology and final ethanol content was studied. The impact of oxygenation on yeast physiology goes beyond the first aerated step and influences yields and survival rates during the anaerobic stage. The activity of M. pulcherrima in mixed oxygenated cultures resulted in a clear reduction in ethanol yield, as compared to S. cerevisiae. Despite relatively low initial cell numbers, S. cerevisiae always predominated in mixed cultures by the end of the fermentation process. Strain replacement was faster under low oxygenation levels. M. pulcherrima confers an additional advantage in terms of dissolved oxygen, which drops to zero after a few hours of culture, even under highly aerated conditions, and this holds true for mixed cultures. Alcohol reduction values about 3.7 % (v/v) were obtained for mixed cultures under high aeration, but they were associated to unacceptable volatile acidity levels. In contrast, under optimized conditions, only 0.35 g/L acetic acid was produced, for an alcohol reduction of 2.2 % (v/v), and almost null dissolved oxygen during the process.

Influence of low oxygen tensions and sorption to sediment black carbon on biodegradation of pyrene.

PubMed

Ortega-Calvo, José-Julio; Gschwend, Philip M

2010-07-01

Sorption to sediment black carbon (BC) may limit the aerobic biodegradation of polycyclic aromatic hydrocarbons (PAHs) in resuspension events and intact sediment beds. We examined this hypothesis experimentally under conditions that were realistic in terms of oxygen concentrations and BC content. A new method, based on synchronous fluorescence observations of (14)C-pyrene, was developed for continuously measuring the uptake of dissolved pyrene by Mycobacterium gilvum VM552, a representative degrader of PAHs. The effect of oxygen and pyrene concentrations on pyrene uptake followed Michaelis-Menten kinetics, resulting in a dissolved oxygen half-saturation constant (K(om)) of 14.1 microM and a dissolved pyrene half-saturation constant (K(pm)) of 6 nM. The fluorescence of (14)C-pyrene in air-saturated suspensions of sediments and induced cells followed time courses that reflected simultaneous desorption and biodegradation of pyrene, ultimately causing a quasi-steady-state concentration of dissolved pyrene balancing desorptive inputs and biodegradation removals. The increasing concentrations of (14)CO(2) in these suspensions, as determined with liquid scintillation, evidenced the strong impact of sorption to BC-rich sediments on the biodegradation rate. Using the best-fit parameter values, we integrated oxygen and sorption effects and showed that oxygen tensions far below saturation levels in water are sufficient to enable significant decreases in the steady-state concentrations of aqueous-phase pyrene. These findings may be relevant for bioaccumulation scenarios that consider the effect of sediment resuspension events on exposure to water column and sediment pore water, as well as the direct uptake of PAHs from sediments.

Heterogeneity in a Suburban River Network: Understanding the Impact of Fluvial Wetlands on Dissolved Oxygen and Metabolism in Headwater Streams

NASA Astrophysics Data System (ADS)

Cain, J. S.; Wollheim, W. M.; Sheehan, K.; Lightbody, A.

2014-12-01

Low dissolved oxygen content in rivers threatens fish populations, aquatic organisms, and the health of entire ecosystems. River systems with high fluvial wetland abundance and organic matter, may result in high metabolism that in conjunction with low re-aeration rates, lead to low oxygen conditions. Increasing abundance of beaver ponds in many areas may exacerbate this phenomenon. This research aims to understand the impact of fluvial wetlands, including beaver ponds, on dissolved oxygen (D.O.) and metabolism throughout the headwaters of the Ipswich R. watershed, MA, USA. In several fluvial wetland dominated systems, we measured diel D.O. and metabolism in the upstream inflow, the surface water transient storage zones of fluvial wetland sidepools, and at the outflow to understand how the wetlands modify dissolved oxygen. D.O. was also measured longitudinally along entire surface water flow paths (x-y km long) to determine how low levels of D.O. propagate downstream. Nutrient samples were also collected to understand how their behavior was related to D.O. behavior. Results show that D.O. in fluvial wetlands has large swings with periods of very low D.O. at night. D.O. swings were also seen in downstream outflow, though lagged and somewhat attenuated. Flow conditions affect the level of inundation and the subsequent effects of fluvial wetlands on main channel D.O.. Understanding the D.O. behavior throughout river systems has important implications for the ability of river systems to remove anthropogenic nitrogen.

Hypolimnetic dissolved-oxygen dynamics within selected White River reservoirs, northern Arkansas-southern Missouri, 1974-2008

USGS Publications Warehouse

De Lanois, Jeanne L.; Green, W. Reed

2011-01-01

Dissolved oxygen is a critical constituent in reservoirs and lakes because it is essential for metabolism by all aerobic aquatic organisms. In general, hypolimnetic temperature and dissolved-oxygen concentrations vary from summer to summer in reservoirs, more so than in natural lakes, largely in response to the magnitude of flow into and release out of the water body. Because eutrophication is often defined as the acceleration of biological productivity resulting from increased nutrient and organic loading, hypolimnetic oxygen consumption rates or deficits often provide a useful tool in analyzing temporal changes in water quality. This report updates a previous report that evaluated hypolimnetic dissolved-oxygen dynamics for a 21-year record (1974-94) in Beaver, Table Rock, Bull Shoals, and Norfork Lakes, as well as analyzed the record for Greers Ferry Lake. Beginning in 1974, vertical profiles of temperature and dissolved-oxygen concentrations generally were collected monthly from March through December at sites near the dam of each reservoir. The rate of change in the amount of dissolved oxygen present below a given depth at the beginning and end of the thermal stratification period is referred to as the areal hypolimnetic oxygen deficit. Areal hypolimnetic oxygen deficit was normalized for each reservoir based on seasonal flushing rate between April 15 and October 31 to adjust for wet year and dry year variability. Annual cycles in thermal stratification within Beaver, Table Rock, Bull Shoals, Norfork, and Greers Ferry Lakes exhibited typical monomictic (one extended turnover period per year) characteristics. Flow dynamics drive reservoir processes and need to be considered when analyzing areal hypolimnetic oxygen deficit rates. A nonparametric, locally weighted scatter plot smooth line describes the relation between areal hypolimnetic oxygen deficit and seasonal flushing rates, without assuming linearity or normality of the residuals. The results in this report are consistent with earlier findings that oxygen deficit rates and flushing-rate adjusted areal hypolimnetic oxygen deficit in Beaver and Table Rock Lakes were decreasing between 1974 and 1994. The additional data (1995-2008) demonstrate that the decline in flushing-rate adjusted areal hypolimnetic oxygen deficit in Beaver Lake has continued, whereas that in Table Rock Lake has flattened out in recent years. The additional data demonstrate the flushing-rate adjusted areal hypolimnetic oxygen deficit in Bull Shoals and Norfork Lakes have declined since 1995 (improved water quality), which was not indicated in earlier studies, while Greers Ferry Lake showed little net change over the period of record. Given the amount of data (35 years) for these reservoirs, developing an equation or model to predict areal hypolimnetic oxygen deficit and, therefore, areal hypolimnetic oxygen content, on any given day during future stratification seasons may be useful for reservoir managers.

A Dissolved Oxygen Threshold for Shifts in Bacterial Community Structure in a Seasonally Hypoxic Estuary.

PubMed

Spietz, Rachel L; Williams, Cheryl M; Rocap, Gabrielle; Horner-Devine, M Claire

2015-01-01

Pelagic ecosystems can become depleted of dissolved oxygen as a result of both natural processes and anthropogenic effects. As dissolved oxygen concentration decreases, energy shifts from macrofauna to microorganisms, which persist in these hypoxic zones. Oxygen-limited regions are rapidly expanding globally; however, patterns of microbial communities associated with dissolved oxygen gradients are not yet well understood. To assess the effects of decreasing dissolved oxygen on bacteria, we examined shifts in bacterial community structure over space and time in Hood Canal, Washington, USA-a glacial fjord-like water body that experiences seasonal low dissolved oxygen levels known to be detrimental to fish and other marine organisms. We found a strong negative association between bacterial richness and dissolved oxygen. Bacterial community composition across all samples was also strongly associated with the dissolved oxygen gradient, and significant changes in bacterial community composition occurred at a dissolved oxygen concentration between 5.18 and 7.12 mg O2 L(-1). This threshold value of dissolved oxygen is higher than classic definitions of hypoxia (<2.0 mg O2 L(-1)), suggesting that changes in bacterial communities may precede the detrimental effects on ecologically and economically important macrofauna. Furthermore, bacterial taxa responsible for driving whole community changes across the oxygen gradient are commonly detected in other oxygen-stressed ecosystems, suggesting that the patterns we uncovered in Hood Canal may be relevant in other low oxygen ecosystems.

Predicting apparent singlet oxygen quantum yields of dissolved black carbon and humic substances using spectroscopic indices.

PubMed

Du, Ziyan; He, Yingsheng; Fan, Jianing; Fu, Heyun; Zheng, Shourong; Xu, Zhaoyi; Qu, Xiaolei; Kong, Ao; Zhu, Dongqiang

2018-03-01

Dissolved black carbon (DBC) is ubiquitous in aquatic systems, being an important subgroup of the dissolved organic matter (DOM) pool. Nevertheless, its aquatic photoactivity remains largely unknown. In this study, a range of spectroscopic indices of DBC and humic substance (HS) samples were determined using UV-Vis spectroscopy, fluorescence spectroscopy, and proton nuclear magnetic resonance. DBC can be readily differentiated from HS using spectroscopic indices. It has lower average molecular weight, but higher aromaticity and lignin content. The apparent singlet oxygen quantum yield (Φ singlet oxygen ) of DBC under simulated sunlight varies from 3.46% to 6.13%, significantly higher than HS, 1.26%-3.57%, suggesting that DBC is the more photoactive component in the DOM pool. Despite drastically different formation processes and structural properties, the Φ singlet oxygen of DBC and HS can be well predicted by the same simple linear regression models using optical indices including spectral slope coefficient (S 275-295 ) and absorbance ratio (E 2 /E 3 ) which are proxies for the abundance of singlet oxygen sensitizers and for the significance of intramolecular charge transfer interactions. The regression models can be potentially used to assess the photoactivity of DOM at large scales with in situ water spectrophotometry or satellite remote sensing. Copyright © 2017 Elsevier Ltd. All rights reserved.

Biochemical Oxygen Demand and Dissolved Oxygen. Training Module 5.105.2.77.

ERIC Educational Resources Information Center

Kirkwood Community Coll., Cedar Rapids, IA.

This document is an instructional module package prepared in objective form for use by an instructor familiar with the azide modification of the Winkler dissolved oxygen test and the electronic dissolved oxygen meter test procedures for determining the dissolved oxygen and the biochemical oxygen demand of a wastewater sample. Included are…

A Dissolved Oxygen Threshold for Shifts in Bacterial Community Structure in a Seasonally Hypoxic Estuary

PubMed Central

Spietz, Rachel L.; Williams, Cheryl M.; Rocap, Gabrielle; Horner-Devine, M. Claire

2015-01-01

Pelagic ecosystems can become depleted of dissolved oxygen as a result of both natural processes and anthropogenic effects. As dissolved oxygen concentration decreases, energy shifts from macrofauna to microorganisms, which persist in these hypoxic zones. Oxygen-limited regions are rapidly expanding globally; however, patterns of microbial communities associated with dissolved oxygen gradients are not yet well understood. To assess the effects of decreasing dissolved oxygen on bacteria, we examined shifts in bacterial community structure over space and time in Hood Canal, Washington, USA−a glacial fjord-like water body that experiences seasonal low dissolved oxygen levels known to be detrimental to fish and other marine organisms. We found a strong negative association between bacterial richness and dissolved oxygen. Bacterial community composition across all samples was also strongly associated with the dissolved oxygen gradient, and significant changes in bacterial community composition occurred at a dissolved oxygen concentration between 5.18 and 7.12 mg O2 L-1. This threshold value of dissolved oxygen is higher than classic definitions of hypoxia (<2.0 mg O2 L-1), suggesting that changes in bacterial communities may precede the detrimental effects on ecologically and economically important macrofauna. Furthermore, bacterial taxa responsible for driving whole community changes across the oxygen gradient are commonly detected in other oxygen-stressed ecosystems, suggesting that the patterns we uncovered in Hood Canal may be relevant in other low oxygen ecosystems. PMID:26270047

Macroalgae in a spring stream in Shanxi Province: composition and relation to physical and chemical variables

NASA Astrophysics Data System (ADS)

Hu, Bianfang; Xie, Shulian

2007-07-01

Fourteen stream segments were investigated throughout the Xin’an Spring in Shanxi Province, China in 2004. The variation ranges in stream size, current velocity, discharge, dissolved oxygen, and specific conductance were large. Twenty-two macroalgae species were found in the stream. Major divisions in terms of species numbers were Chlorophyta (59.1%), Cyanophyta (22.8%), Xanthophyta (9.1%), Rhodophyta (4.5%) and Charophyta (4.5%). The most widespread species, Cladophora rivularis (50.0%), also Oedogonium sp. (42.9%) and Spirogyra sp. (42.9%) were well represented throughout the stream, whereas another 10 species were found in only one sampling site. Total percentage cover varied from <1% to 90%. Red algae Batrachospermum acuatum and the charophytes Chara vulgaris have the highest percentage cover. Among the parameters analyzed, the stream width, specific conductance and dissolved oxygen were the ones that more closely related to the species number and percentage cover of macroalgal communities. The species number of each site was negatively correlated with dissolved oxygen content. The total percentage cover of the macroalgae was negatively correlated with the stream width and the specific conductance.

[Influence of dissolved gases on highly diluted aqueous media].

PubMed

Belovolova, L V; Glushkov, M V; Vinogradov, E A

2014-01-01

In the experiments on redox potential measurement for a series of identical samples of purified and presettled water it was found that the response to ultraviolet irradiation varies appreciably within a few days after treatment, including stepwise changes. In a few hours after exposure, leading to a higher content of reactive oxygen species as compared with the equilibrium values, long-term changes including variations in redox potential and optical system parameters are recorded in water and diluted aqueous media. We propose a heuristic organization model of the water-gas system with an increased content of reactive oxygen species.

The Nation's Rivers

ERIC Educational Resources Information Center

Wolman, M. Gordon

1971-01-01

Illustrates difficulties in measuring long term changes in water temperature and content of dissolved oxygen, inorganic ions, radiation, pesticides, and trash and debris by reference to selected U. S. river systems. Concludes that observations to detect polluters may not provide data for assessing trends and trend reversals. (AL)

Characteristics of water quality and streamflow, Passaic River basin above Little Falls, New Jersey

USGS Publications Warehouse

Anderson, Peter W.; Faust, Samuel Denton

1973-01-01

The findings of a problem-oriented river-system investigation of the water-quality and streamflow characteristics of the Passaic River above Little Falls, N.J. (drainage area 762 sq mi) are described. Information on streamflow duration, time-of-travel measurements, and analyses of chemical, biochemical, and physical water quality are summarized. This information is used to define relations between water quality, streamflow, geology, and environmental development in the basin's hydrologic system. The existence, nature, and magnitude of long-term trends in stream quality--as measured by dissolved solids, chloride, dissolved oxygen, biochemical oxygen demand, ammonia, nitrate, and turbidity--and in streamflow toward either improvement or deterioration are appraised at selected sites within the river system. The quality of streams in the upper Passaic River basin in northeastern New Jersey is shown to be deteriorating with time. For example, biochemical oxygen demand, an indirect measure of organic matter in a stream, is increasing at most stream-quality sampling sites. Similarly, the dissolved-solids content, a measure of inorganic matter, also is increasing. These observations suggest that the Passaic River system is being used more and more as a medium for the disposal of industrial and municipal waste waters. Dissolved oxygen, an essential ingredient for the natural purification of streams receiving waste discharges, is undersaturated (that is, below theoretical solubility levels) at all sampling sites and is decreasing with time at most sites. This is another indication of the general deterioration of stream quality in the upper basin. It also indicates that the ability of the river system to receive, transport, and assimilate wastes, although exceeded now only for short periods during the summer months, may be exceeded more continually in the future if present trends hold. Decreasing ratios of ammonia to nitrate in a downstream direction on the main stem Passaic River suggests that nitrification (the biochemical conversion of ammonia to nitrate) as well as microbiological decomposition of organic matter (waste waters) is contributing to the continued and increasing undersaturation of dissolved oxygen in the river system. Passaic River streams are grouped into five general regions of isochemical quality on the basis of predominant constituents and dissolved-solids content during low flows. The predominant cations in all but one region are calcium and magnesium (exceeding 50 percent of total cations) ; in that region, where man's activities probably have altered the natural stream waters, the percentage of sodium and potassium equals that of calcium and magnesium. In two of the five regions, the predominant anion is bicarbonate; a combination of sulfate, chloride, and nitrate is predominant in the other three regions. Dissolved-solids content during low flows generally ranges from 100 to 600 milligrams per liter. Several time-of-travel measurements within the basin are reported. These data provide reasonable estimates of the time required for soluble contaminants to pass through particular parts of the river system. For example, the peak concentration of a contaminant injected into the river system at Chatham during extreme low flow would be expected to travel to Little Falls, about 31 miles, in about 13 days; but at medium flow, in about 5 days.

Water quality and processes affecting dissolved oxygen concentrations in the Blackwater River, Canaan Valley, West Virginia

USGS Publications Warehouse

Waldron, M.C.; Wiley, J.B.

1996-01-01

The water quality and environmental processes affecting dissolved oxygen were determined for the Blackwater River in Canaan Valley, West Virginia. Canaan Valley is oval-shaped (14 miles by 5 miles) and is located in the Allegheny Mountains at an average elevation of 3,200 feet above sea level. Tourism, population, and real estate development have increased in the past two decades. Most streams in Canaan Valley are a dilute calcium magnesium bicarbonate-type water. Streamwater typicaly was soft and low in alkalinity and dissolved solids. Maximum values for specific conductance, hardness, alkalinity, and dissolved solids occurred during low-flow periods when streamflow was at or near baseflow. Dissolved oxygen concentrations are most sensitive to processes affecting the rate of reaeration. The reaeration is affected by solubility (atmospheric pressure, water temperature, humidity, and cloud cover) and processes that determine stream turbulence (stream depth, width, velocity, and roughness). In the headwaters, photosynthetic dissolved oxygen production by benthic algae can result in supersaturated dissolved oxygen concentrations. In beaver pools, dissolved oxygen consumption from sediment oxygen demand and carbonaceous biochemical oxygen demand can result in dissolved oxygen deficits.

Water Habitat Study: Prediction Makes It More Meaningful.

ERIC Educational Resources Information Center

Glasgow, Dennis R.

1982-01-01

Suggests a teaching strategy for water habitat studies to help students make a meaningful connection between physiochemical data (dissolved oxygen content, pH, and water temperature) and biological specimens they collect. Involves constructing a poster and using it to make predictions. Provides sample poster. (DC)

Chemical evidence of the changes of the Antarctic Bottom Water ventilation in the western Ross Sea between 1997 and 2003

NASA Astrophysics Data System (ADS)

Rivaro, Paola; Massolo, Serena; Bergamasco, Andrea; Castagno, Pasquale; Budillon, Giorgio

2010-05-01

Data from three Italian CLIMA project cruises between 1997 and 2003 were used to obtain sections of the hydrographic and chemical properties of the main water masses across the shelf break off Cape Adare (western Ross Sea, Antarctica). Dissolved oxygen, nitrate and phosphate data were combined on the basis of the Redfield ratio to obtain the quasi-conservative tracers NO (9[NO 3]+[O 2]), PO (135[PO 4]+[O 2]) and phosphate star PO4* ( PO4*=[PO 4]+[O 2]/175-1.95). In 1997 and 2003 the presence of the High Salinity Shelf Water at the bottom depth near the sill was traced by both physical and chemical measurements. In 2001 the Modified Shelf Water, characterized by warmer temperature and by a lower dissolved oxygen content than High Salinity Shelf Water, was observed at the shelf edge. The distribution of the chemical tracers together with the hydrographic observations showed recently formed Antarctic Bottom Water on the continental slope during all of the cruises. These observations were confirmed by the extended optimum multiparameter analysis. The calculated thickness of the new Antarctic Bottom Water, as well as the tracer content, were variable in time and in space. The estimated volume of the new Antarctic Bottom Water and the export of dissolved oxygen and nutrient associated with the overflowing water were different over the examined period. In particular, a lower (˜55%) export was evidenced in 2001 compared to 1997.

Quantitation of dissolved gas content in emulsions and in blood using mass spectrometric detection

PubMed Central

Grimley, Everett; Turner, Nicole; Newell, Clayton; Simpkins, Cuthbert; Rodriguez, Juan

2011-01-01

Quantitation of dissolved gases in blood or in other biological media is essential for understanding the dynamics of metabolic processes. Current detection techniques, while enabling rapid and convenient assessment of dissolved gases, provide only direct information on the partial pressure of gases dissolved in the aqueous fraction of the fluid. The more relevant quantity known as gas content, which refers to the total amount of the gas in all fractions of the sample, can be inferred from those partial pressures, but only indirectly through mathematical modeling. Here we describe a simple mass spectrometric technique for rapid and direct quantitation of gas content for a wide range of gases. The technique is based on a mass spectrometer detector that continuously monitors gases that are rapidly extracted from samples injected into a purge vessel. The accuracy and sample processing speed of the system is demonstrated with experiments that reproduce within minutes literature values for the solubility of various gases in water. The capability of the technique is further demonstrated through accurate determination of O2 content in a lipid emulsion and in whole blood, using as little as 20 μL of sample. The approach to gas content quantitation described here should greatly expand the range of animals and conditions that may be used in studies of metabolic gas exchange, and facilitate the development of artificial oxygen carriers and resuscitation fluids. PMID:21497566

The Evolution of Deepwater Dissolved Oxygen in the Northern South China Sea During the Past 400 ka

NASA Astrophysics Data System (ADS)

Wang, N.; Huang, B.; Dong, Y.

2016-12-01

Reconstruction of dissolved oxygen in paleo-ocean contributes toward understanding the history of ocean circulation, climate, causes of extinctions, and the evolution of marine organisms. Based on analysis of benthic foraminifera oxygen index (BFOI), the redox-sensitive trace elements (Mo/Al), the percentage of epifaunal benthic foraminifera and infaunal/epifaunal ratio at core MD12-3432, we reconstruct the evolution of deep water dissolved oxygen in northern South China Sea (SCS) during the past 400 ka and discuss the mechanisms of variable dissolved oxygen. Both BFOI and Mo/Al are redox indicators. Similar trends confirm that they reflect the variation of dissolved oxygen in seawater since 400 ka accurately. BFOI and Mo/Al indicate that dissolved oxygen was high in MIS 11-MIS 7 and decreased gradually during MIS 6- MIS 2. The percentage of epifauna decreased and infaunal/epifaunal ratio increased with decreasing dissolved oxygen. By comparison of dissolved oxygen and productivity indexes such as phytoplankton total (PT) and species abundances, we found that when PT fluctuated in the average range of 1000-1500 ng/g, the abundances of Bulimina and Uvigerina which represent high productivity increased. However, when PT reached the range of 2500-3000 ng/g, the abundances of Bulimina and Uvigerina didn't increase, but the abundances of dysoxic species Chilostomella oolina and Globobulimina pacifica increased and the dissolved oxygen reached low value. The reasons may be that the decomposition of excessive organic matter consumed more dissolved oxygen. The low dissolved oxygen suppressed the growth of Bulimina and Uvigerina and accelerated the boom of C. oolina and G. oolina. The dissolved oxygen is not only associated with productivity, but also affected by the thermohaline circulation. Benthic foraminifera F. favus is the representative species in Pacific deep water. Its appearance at 194 ka, 205 ka, 325, the 328 ka in MD12-3432 indicate that the upper border of western Pacific deep water was beyond the sill of Bashi Strait and high dissolved oxygen deep water was brought into Northern SCS. The millennium-scale rapid variability and decline of dissolved oxygen in MIS 4, 3, 2 may be caused by fluctuations and slowdown of thermohaline circulation transported from the northern Atlantic to the northern SCS.

Prediction model of dissolved oxygen in ponds based on ELM neural network

NASA Astrophysics Data System (ADS)

Li, Xinfei; Ai, Jiaoyan; Lin, Chunhuan; Guan, Haibin

2018-02-01

Dissolved oxygen in ponds is affected by many factors, and its distribution is unbalanced. In this paper, in order to improve the imbalance of dissolved oxygen distribution more effectively, the dissolved oxygen prediction model of Extreme Learning Machine (ELM) intelligent algorithm is established, based on the method of improving dissolved oxygen distribution by artificial push flow. Select the Lake Jing of Guangxi University as the experimental area. Using the model to predict the dissolved oxygen concentration of different voltage pumps, the results show that the ELM prediction accuracy is higher than the BP algorithm, and its mean square error is MSEELM=0.0394, the correlation coefficient RELM=0.9823. The prediction results of the 24V voltage pump push flow show that the discrete prediction curve can approximate the measured values well. The model can provide the basis for the artificial improvement of the dissolved oxygen distribution decision.

Surface-water hydrology and quality, and macroinvertebrate and smallmouth bass populations in four stream basins in southwestern Wisconsin, 1987-90

USGS Publications Warehouse

Graczyk, David J.; Lillie, Richard A.; Schlesser, Roger A.; Mason, John W.; Lyons, John D.; Kerr, Roger A.; Graczyk, David J.

1993-01-01

Low concentrations of dissolved oxygen constituted the most detrimental water-quality problem affecting smallmouth bass populations. Dissolved-oxygen concentrations were occasionally less than 3 milligrams per liter, a dissolved-oxygen concentration that may be detrimental to early-life stages of smallmouth bass in the streams; however, smallmouth bass were apparently able to withstand these low dissolved-oxygen concentrations and seem to have survived in some situations when dissolved-oxygen concentration decreased to1 milligram per liter.

Organic carbon accumulation and preservation in surface sediments on the Peru margin

USGS Publications Warehouse

Arthur, M.A.; Dean, W.E.; Laarkamp, K.

1998-01-01

Concentrations and characteristics of organic matter in surface sediments deposited under an intense oxygen-minimum zone on the Peru margin were studied in samples from deck-deployed box cores and push cores acquired by submersible on two transects spanning depths of 75 to 1000 m at 12??and 13.5??S. The source of organic matter to the seafloor in these areas is almost entirely marine material as confirmed by the narrow range of ??13C of organic carbon obtained in the present study (-20.3 to -21.6???; PDB) and the lack of any relationship between pyrolysis hydrogen index and carbon isotope composition. Organic carbon contents are highest (up to 16%) on the slope at depths between 75 and 350 m in sediments deposited under intermediate water masses with low dissolved oxygen concentrations (< 5 ??mol/kg). Even at these low concentrations of dissolved oxygen, however, the surface sediments that were recovered from these depths are dominantly unlaminated. Strong currents (up to 30 cm/s) associated with the poleward-flowing Peru Undercurrent were measured at depths between 160 and 300 m on both transects. The seafloor in this range of water depths is characterized by bedforms stabilized by bacterial mats, extensive authigenic mineral crusts, and (or) thick organic flocs. Constant advection of dissolved oxygen, although in low concentrations, active resuspension of surficial organic matter, activity of organisms, and transport of fine-grained sediment to and from more oxygenated zones all contribute to greater degradation and poorer initial preservation of organic matter than might be expected under oxygen-deficient conditions. Dissolved-oxygen concentrations ultimately may be the dominant affect on organic matter characteristics, but reworking of fine-grained sediment and organic matter by strong bottom currents and redeposition on the seafloor in areas of lower energy also exert important controls on organic carbon concentration and degree of oxidation in this region.

Radical scavenger can scavenge lipid allyl radicals complexed with lipoxygenase at lower oxygen content.

PubMed

Koshiishi, Ichiro; Tsuchida, Kazunori; Takajo, Tokuko; Komatsu, Makiko

2006-04-15

Lipoxygenases have been proposed to be a possible factor that is responsible for the pathology of certain diseases, including ischaemic injury. In the peroxidation process of linoleic acid by lipoxygenase, the E,Z-linoleate allyl radical-lipoxygenase complex seems to be generated as an intermediate. In the present study, we evaluated whether E,Z-linoleate allyl radicals on the enzyme are scavenged by radical scavengers. Linoleic acid, the content of which was greater than the dissolved oxygen content, was treated with soya bean lipoxygenase-1 (ferric form) in the presence of radical scavenger, CmP (3-carbamoyl-2,2,5,5-tetramethylpyrrolidine-N-oxyl). The reaction rate between oxygen and lipid allyl radical is comparatively faster than that between CmP and lipid allyl radical. Therefore a reaction between linoleate allyl radical and CmP was not observed while the dioxygenation of linoleic acid was ongoing. After the dissolved oxygen was depleted, CmP stoichiometrically trapped linoleate-allyl radicals. Accompanied by this one-electron redox reaction, the resulting ferrous lipoxygenase was re-oxidized to the ferric form by hydroperoxylinoleate. Through the adduct assay via LC (liquid chromatography)-MS/MS (tandem MS), four E,Z-linoleate allyl radical-CmP adducts corresponding to regio- and diastereo-isomers were detected in the linoleate/lipoxygenase system, whereas E,E-linoleate allyl radical-CmP adducts were not detected at all. If E,Z-linoleate allyl radical is liberated from the enzyme, the E/Z-isomer has to reach equilibrium with the thermodynamically favoured E/E-isomer. These data suggested that the E,Z-linoleate allyl radicals were not liberated from the active site of lipoxygenase before being trapped by CmP. Consequently, we concluded that the lipid allyl radicals complexed with lipoxygenase could be scavenged by radical scavengers at lower oxygen content.

Radical scavenger can scavenge lipid allyl radicals complexed with lipoxygenase at lower oxygen content

PubMed Central

Koshiishi, Ichiro; Tsuchida, Kazunori; Takajo, Tokuko; Komatsu, Makiko

2006-01-01

Lipoxygenases have been proposed to be a possible factor that is responsible for the pathology of certain diseases, including ischaemic injury. In the peroxidation process of linoleic acid by lipoxygenase, the E,Z-linoleate allyl radical–lipoxygenase complex seems to be generated as an intermediate. In the present study, we evaluated whether E,Z-linoleate allyl radicals on the enzyme are scavenged by radical scavengers. Linoleic acid, the content of which was greater than the dissolved oxygen content, was treated with soya bean lipoxygenase-1 (ferric form) in the presence of radical scavenger, CmP (3-carbamoyl-2,2,5,5-tetramethylpyrrolidine-N-oxyl). The reaction rate between oxygen and lipid allyl radical is comparatively faster than that between CmP and lipid allyl radical. Therefore a reaction between linoleate allyl radical and CmP was not observed while the dioxygenation of linoleic acid was ongoing. After the dissolved oxygen was depleted, CmP stoichiometrically trapped linoleate-allyl radicals. Accompanied by this one-electron redox reaction, the resulting ferrous lipoxygenase was re-oxidized to the ferric form by hydroperoxylinoleate. Through the adduct assay via LC (liquid chromatography)–MS/MS (tandem MS), four E,Z-linoleate allyl radical–CmP adducts corresponding to regio- and diastereo-isomers were detected in the linoleate/lipoxygenase system, whereas E,E-linoleate allyl radical–CmP adducts were not detected at all. If E,Z-linoleate allyl radical is liberated from the enzyme, the E/Z-isomer has to reach equilibrium with the thermodynamically favoured E/E-isomer. These data suggested that the E,Z-linoleate allyl radicals were not liberated from the active site of lipoxygenase before being trapped by CmP. Consequently, we concluded that the lipid allyl radicals complexed with lipoxygenase could be scavenged by radical scavengers at lower oxygen content. PMID:16396633

Assessment of temporal and spatial water quality in international Gomishan Lagoon, Iran, using multivariate analysis.

PubMed

Basatnia, Nabee; Hossein, Seyed Abbas; Rodrigo-Comino, Jesús; Khaledian, Yones; Brevik, Eric C; Aitkenhead-Peterson, Jacqueline; Natesan, Usha

2018-04-29

Coastal lagoon ecosystems are vulnerable to eutrophication, which leads to the accumulation of nutrients from the surrounding watershed over the long term. However, there is a lack of information about methods that could accurate quantify this problem in rapidly developed countries. Therefore, various statistical methods such as cluster analysis (CA), principal component analysis (PCA), partial least square (PLS), principal component regression (PCR), and ordinary least squares regression (OLS) were used in this study to estimate total organic matter content in sediments (TOM) using other parameters such as temperature, dissolved oxygen (DO), pH, electrical conductivity (EC), nitrite (NO 2 ), nitrate (NO 3 ), biological oxygen demand (BOD), phosphate (PO 4 ), total phosphorus (TP), salinity, and water depth along a 3-km transect in the Gomishan Lagoon (Iran). Results indicated that nutrient concentration and the dissolved oxygen gradient were the most significant parameters in the lagoon water quality heterogeneity. Additionally, anoxia at the bottom of the lagoon in sediments and re-suspension of the sediments were the main factors affecting internal nutrient loading. To validate the models, R 2 , RMSECV, and RPDCV were used. The PLS model was stronger than the other models. Also, classification analysis of the Gomishan Lagoon identified two hydrological zones: (i) a North Zone characterized by higher water exchange, higher dissolved oxygen and lower salinity and nutrients, and (ii) a Central and South Zone with high residence time, higher nutrient concentrations, lower dissolved oxygen, and higher salinity. A recommendation for the management of coastal lagoons, specifically the Gomishan Lagoon, to decrease or eliminate nutrient loadings is discussed and should be transferred to policy makers, the scientific community, and local inhabitants.

Modern and ancient geochemical constraints on Proterozoic atmosphere-ocean redox evolution

NASA Astrophysics Data System (ADS)

Hardisty, D. S.; Horner, T. J.; Wankel, S. D.; Lu, Z.; Lyons, T.; Nielsen, S.

2017-12-01

A detailed understanding of the spatiotemporal oxygenation of Earth's atmosphere-ocean system through the Precambrian has important implications for the environments capable of sustaining early eukaryotic life and the evolving oxidant budget of subducted sediments. Proxy records suggest an anoxic Fe-rich deep ocean through much of the Precambrian and atmospheric and surface-ocean oxygenation that started in earnest at the Paleoproterozoic Great Oxidation Event (GOE). The marine photic zone represented the initial site of oxygen production and accumulation via cyanobacteria, yet our understanding of surface-ocean oxygen contents and the extent and timing of oxygen propagation and exchange between the atmosphere and deeper ocean are limited. Here, we present an updated perspective of the constraints on atmospheric, surface-ocean, and deep-ocean oxygen contents starting at the GOE. Our research uses the iodine content of Proterozoic carbonates as a tracer of dissolved iodate in the shallow ocean, a redox-sensitive species quantitatively reduced in modern oxygen minimum zones. We supplement our understanding of the ancient record with novel experiments examining the rates of iodate production from oxygenated marine environments based on seawater incubations. Combining new data from iodine with published shallow marine (Ce anomaly, N isotopes) and atmospheric redox proxies, we provide an integrated view of the vertical redox structure of the atmosphere and ocean across the Proterozoic.

Efficient fluorescence "turn-on" sensing of dissolved oxygen by electrochemical switching.

PubMed

Shin, Ik-Soo; Hirsch, Thomas; Ehrl, Benno; Jang, Dong-Hak; Wolfbeis, Otto S; Hong, Jong-In

2012-11-06

We report on a novel method for sensing oxygen that is based on the use of a perylene diimide dye (1) which is electrochemically reduced to its nonfluorescent dianion form (1(2-)). In the presence of oxygen, the dianion is oxidized to its initial form via an electron-transfer reaction with oxygen upon which fluorescence is recovered. As a result, the fluorescence intensity of the dianion solution increases upon the addition of oxygen gas. Results demonstrate that high sensitivity is obtained, and the emission intensity shows a linear correlation with oxygen content (0.0-4.0% v/v) at ambient barometric pressure. In addition, using electrochemical reduction, oxygen determination becomes regenerative, and no significant degradation is observed over several turnovers. The limit of detection is 0.4% oxygen in argon gas.

The effect of dissolved oxygen on the relaxation rates of blood plasma: Implications for hyperoxia calibrated BOLD.

PubMed

Ma, Yuhan; Berman, Avery J L; Pike, G Bruce

2016-12-01

To determine the contribution of paramagnetic dissolved oxygen in blood plasma to blood-oxygenation-level-dependent (BOLD) signal changes in hyperoxic calibrated BOLD studies. Bovine blood plasma samples were prepared with partial pressures of oxygen (pO 2 ) ranging from 110 to 600 mmHg. R 1 , R 2 , and R 2 * of the plasma with dissolved oxygen were measured using quantitative MRI sequences at 3 Tesla. Simulations were performed to predict the relative effects of dissolved oxygen and deoxyhemoglobin changes in hyperoxia calibrated BOLD. The relaxivities of dissolved oxygen in plasma were found to be r 1, O2 =1.97 ± 0.09 ×10 -4 s -1 mmHg -1 , r 2, O2 =2.3 ± 0.7 ×10 -4 s -1 mmHg -1 , and r 2, O2 * = 2.3 ± 0.7 ×10 -4 s -1 mmHg -1 . Simulations predict that neither the transverse nor longitudinal relaxation rates of dissolved oxygen contribute significantly to the BOLD signal during hyperoxia. During hyperoxia, the increases in R 2 and R 2 * of blood from dissolved oxygen in plasma are considerably less than the decreases in R 2 and R 2 * from venous deoxyhemoglobin. R 1 effects due to dissolved oxygen are also predicted to be negligible. As a result, dissolved oxygen in arteries should not contribute significantly to the hyperoxic calibrated BOLD signal. Magn Reson Med 76:1905-1911, 2016. © 2015 International Society for Magnetic Resonance in Medicine. © 2015 International Society for Magnetic Resonance in Medicine.

Robust optode-based method for measuring in situ oxygen profiles in gravelly streambeds.

PubMed

Vieweg, Michael; Trauth, Nico; Fleckenstein, Jan H; Schmidt, Christian

2013-09-03

One of the key environmental conditions controlling biogeochemical reactions in aquatic sediments like streambeds is the distribution of dissolved oxygen. We present a novel approach for the in situ measurement of vertical oxygen profiles using a planar luminescence-based optical sensor. The instrument consists of a transparent acrylic tube with the oxygen-sensitive layer mounted on the outside. The luminescence is excited and detected by a moveable piston inside the acrylic tube. Since no moving parts are in contact with the streambed, the disturbance of the subsurface flow field is minimized. The precision of the distributed oxygen sensor (DOS) was assessed by a comparison with spot optodes. Although the precision of the DOS, expressed as standard deviation of calculated oxygen air saturation, is lower (0.2-6.2%) compared to spot optodes (<0.1-0.6%), variations of the oxygen content along the profile can be resolved. The uncertainty of the calculated oxygen is assessed with a Monte Carlo uncertainty assessment. The obtained vertical oxygen profiles of 40 cm in length reveal variations of the oxygen content reaching from 90% to 0% air saturation and are characterized by patches of low oxygen rather than a continuous decrease with depth.

Concentrations of dissolved oxygen in the lower Puyallup and White rivers, Washington, August and September 2000 and 2001

USGS Publications Warehouse

Ebbert, J.C.

2002-01-01

The U.S. Geological Survey, Washington State Department of Ecology, and Puyallup Tribe of Indians conducted a study in August and September 2001 to assess factors affecting concentrations of dissolved oxygen in the lower Puyallup and White Rivers, Washington. The study was initiated because observed concentrations of dissolved oxygen in the lower Puyallup River fell to levels ranging from less than 1 milligram per liter (mg/L) to about 6 mg/L on several occasions in September 2000. The water quality standard for the concentration of dissolved oxygen in the Puyallup River is 8 mg/L.This study concluded that inundation of the sensors with sediment was the most likely cause of the low concentrations of dissolved oxygen observed in September 2000. The conclusion was based on (1) knowledge gained when a dissolved-oxygen sensor became covered with sediment in August 2001, (2) the fact that, with few exceptions, concentrations of dissolved oxygen in the lower Puyallup and White Rivers did not fall below 8 mg/L in August and September 2001, and (3) an analysis of other mechanisms affecting concentrations of dissolved oxygen.The analysis of other mechanisms indicated that they are unlikely to cause steep declines in concentrations of dissolved oxygen like those observed in September 2000. Five-day biochemical oxygen demand ranged from 0.22 to 1.78 mg/L (mean of 0.55 mg/L), and river water takes only about 24 hours to flow through the study reach. Photosynthesis and respiration cause concentrations of dissolved oxygen in the lower Puyallup River to fluctuate as much as about 1 mg/L over a 24-hour period in August and September. Release of water from Lake Tapps for the purpose of hydropower generation often lowered concentrations of dissolved oxygen downstream in the White River by about 1 mg/L. The effect was smaller farther downstream in the Puyallup River at river mile 5.8, but was still observable as a slight decrease in concentrations of dissolved oxygen caused by photosynthesis and respiration. The upper limit on oxygen demand caused by the scour of anoxic bed sediment and subsequent oxidation of reduced iron and manganese is less than 1 mg/L. The actual demand, if any, is probably negligible.In August and September 2001, concentrations of dissolved oxygen in the lower Puyallup River did not fall below the water-quality standard of 8 mg/L, except at high tide when the saline water from Commencement Bay reached the monitor at river mile 2.9. The minimum concentration of dissolved oxygen (7.6 mg/L) observed at river mile 2.9 coincided with the maximum value of specific conductance. Because the dissolved-oxygen standard for marine water is 6.0 mg/L, the standard was not violated at river mile 2.9. The concentration of dissolved oxygen at river mile 1.8 in the White River dropped below the water-quality standard on two occasions in August 2001. The minimum concentration of 7.8 mg/L occurred on August 23, and a concentration of 7.9 mg/L was recorded on August 13. Because there was some uncertainty in the monitoring record for those days, it cannot be stated with certainty that the actual concentration of dissolved oxygen in the river dropped below 8 mg/L. However, at other times when the quality of the monitoring record was good, concentrations as low as 8.2 mg/L were observed at river mile 1.8 in the White River.

Enhanced dissolution of cinnabar (mercuric sulfide) by dissolved organic matter isolated from the Florida Everglades

USGS Publications Warehouse

Ravichandran, Mahalingam; Aiken, George R.; Reddy, Michael M.; Ryan, Joseph N.

1998-01-01

Organic matter isolated from the Florida Everglades caused a dramatic increase in mercury release (up to 35 μM total dissolved mercury) from cinnabar (HgS), a solid with limited solubility. Hydrophobic (a mixture of both humic and fulvic) acids dissolved more mercury than hydrophilic acids and other nonacid fractions of dissolved organic matter (DOM). Cinnabar dissolution by isolated organic matter and natural water samples was inhibited by cations such as Ca2+. Dissolution was independent of oxygen content in experimental solutions. Dissolution experiments conducted in DI water (pH = 6.0) had no detectable (<2.5 nM) dissolved mercury. The presence of various inorganic (chloride, sulfate, or sulfide) and organic ligands (salicylic acid, acetic acid, EDTA, or cysteine) did not enhance the dissolution of mercury from the mineral. Aromatic carbon content in the isolates (determined by 13C NMR) correlated positively with enhanced cinnabar dissolution. ζ-potential measurements indicated sorption of negatively charged organic matter to the negatively charged cinnabar (pHpzc = 4.0) at pH 6.0. Possible mechanisms of dissolution include surface complexation of mercury and oxidation of surface sulfur species by the organic matter.

The quality of surface waters in Texas

USGS Publications Warehouse

Rawson, Jack

1974-01-01

The discharge-weighted average concentrations of dissolved solids, chloride, and ,sulfate for many of the principal streams in Texas are less than 500 mg/l (millijgraljls per liter), 250 mg/l, and 250 mg/l, respectively. At 65 of 131 sites on streams that were sampled at least 10 times, the biochemical oxygen demand of at least half the samples exceeded 3.0 mg/l. At 20 of the sites, the dissolved-oxygen content of at least half the samples was less than 5.0 mg/l. The higher concentrations of minor elements usually were detected in waters from urban areas, indicating a relation to man's activities. Small amounts of some pesticides are widely distributed in low concentrations. The higher concentrations usually were detected in waters from urban areas.

Correlation between the sorption of dissolved oxygen onto chitosan and its antimicrobial activity against Esherichia coli.

PubMed

Gylienė, Ona; Servienė, Elena; Vepštaitė, Iglė; Binkienė, Rima; Baranauskas, Mykolas; Lukša, Juliana

2015-10-20

The ability of chitosan to adsorb dissolved oxygen from solution depends on its physical shape and is related to the surface area. Depending on conditions chitosan is capable of adsorbing or releasing oxygen. Chitosan, modificated by the substances possessing antimicrobial activity, such as succinic acid, Pd(II) ions, metallic Pd or Ag, distinctly increases the ability to adsorb the dissolved oxygen. The additional treatment of chitosan with air oxygen or electrochemically produced oxygen also increases the uptake of dissolved oxygen by chitosan. A strong correlation between the amount of oxygen adsorbed onto chitosan and its antimicrobial activity against Esherichia coli has been observed. This finding suggests that one of the sources of antimicrobial activity of chitosan is the ability to sorb dissolved oxygen, along with other well-known factors such as physical state and chemical composition. Copyright © 2015 Elsevier Ltd. All rights reserved.

Catalytic Reduction of 4-Nitrophenol: A Quantitative Assessment of the Role of Dissolved Oxygen in Determining the Induction Time.

PubMed

Menumerov, Eredzhep; Hughes, Robert A; Neretina, Svetlana

2016-12-14

The reduction of 4-nitrophenol to 4-aminophenol by borohydride is one of the foremost model catalytic reactions because it allows for a straightforward assessment of catalysts using the kinetic parameters extracted from the real-time spectroscopic monitoring of an aqueous solution. Crucial to its standing as a model reaction is a comprehensive mechanistic framework able to explain the entire time evolution of the reaction. While much of this framework is in place, there is still much debate over the cause of the induction period, an initial time interval where no reaction seemingly occurs. Here, we report on the simultaneous monitoring of the spectroscopic signal and the dissolved oxygen content within the aqueous solution. It reveals that the induction period is the time interval required for the level of dissolved oxygen to fall below a critical value that is dependent upon whether Au, Ag, or Pd nanoparticles are used as the catalyst. With this understanding, we are able to exert complete control over the induction period, being able to eliminate it, extend it indefinitely, or even induce multiple induction periods over the course of a single reaction. Moreover, we have determined that the reaction product, 4-aminophenol, in the presence of the same catalyst reacts with dissolved oxygen to form 4-nitrophenolate. The implication of these results is that the induction period relates, not to some activation of the catalyst, but to a time interval where the reaction product is being rapidly transformed back into a reactant by a side reaction.

Quantitation of dissolved gas content in emulsions and in blood using mass spectrometric detection.

PubMed

Grimley, Everett; Turner, Nicole; Newell, Clayton; Simpkins, Cuthbert; Rodriguez, Juan

2011-06-01

Quantitation of dissolved gases in blood or in other biological media is essential for understanding the dynamics of metabolic processes. Current detection techniques, while enabling rapid and convenient assessment of dissolved gases, provide only direct information on the partial pressure of gases dissolved in the aqueous fraction of the fluid. The more relevant quantity known as gas content, which refers to the total amount of the gas in all fractions of the sample, can be inferred from those partial pressures, but only indirectly through mathematical modeling. Here we describe a simple mass spectrometric technique for rapid and direct quantitation of gas content for a wide range of gases. The technique is based on a mass spectrometer detector that continuously monitors gases that are rapidly extracted from samples injected into a purge vessel. The accuracy and sample processing speed of the system is demonstrated with experiments that reproduce within minutes literature values for the solubility of various gases in water. The capability of the technique is further demonstrated through accurate determination of O(2) content in a lipid emulsion and in whole blood, using as little as 20 μL of sample. The approach to gas content quantitation described here should greatly expand the range of animals and conditions that may be used in studies of metabolic gas exchange, and facilitate the development of artificial oxygen carriers and resuscitation fluids. Copyright © 2011 Elsevier B.V. All rights reserved.

Development of an aquaculture system using nanobubble technology for the optimation of dissolved oxygen in culture media for nile tilapia (Oreochromis niloticus)

NASA Astrophysics Data System (ADS)

Mahasri, G.; Saskia, A.; Apandi, P. S.; Dewi, N. N.; Rozi; Usuman, N. M.

2018-04-01

The purpose of this research was to discover the process of enrichment of dissolved oxygen in fish cultivation media using nanobubble technology. This study was conducted with two treatments, namely a cultivation media without fish and a cultivation media containing 8 fish with an average body length of 24.5 cm. The results showed that the concentration of dissolved oxygen increased from 6.5 mg/L to 25 mg/L. The rate of increase in dissolved oxygen concentration for 30 minutes is 0.61 pp/minute. The rate of decrease in dissolved oxygen concentration in treatment 1 is 3.08 ppm/day and in treatment 2 is 0.23 ppm/minute. It was concluded that nanobubble is able to increase dissolved oxygen.

Undocumented water column sink for cadmium in open ocean oxygen-deficient zones

PubMed Central

Janssen, David J.; Conway, Tim M.; John, Seth G.; Christian, James R.; Kramer, Dennis I.; Pedersen, Tom F.; Cullen, Jay T.

2014-01-01

Cadmium (Cd) is a micronutrient and a tracer of biological productivity and circulation in the ocean. The correlation between dissolved Cd and the major algal nutrients in seawater has led to the use of Cd preserved in microfossils to constrain past ocean nutrient distributions. However, linking Cd to marine biological processes requires constraints on marine sources and sinks of Cd. Here, we show a decoupling between Cd and major nutrients within oxygen-deficient zones (ODZs) in both the Northeast Pacific and North Atlantic Oceans, which we attribute to Cd sulfide (CdS) precipitation in euxinic microenvironments around sinking biological particles. We find that dissolved Cd correlates well with dissolved phosphate in oxygenated waters, but is depleted compared with phosphate in ODZs. Additionally, suspended particles from the North Atlantic show high Cd content and light Cd stable isotope ratios within the ODZ, indicative of CdS precipitation. Globally, we calculate that CdS precipitation in ODZs is an important, and to our knowledge a previously undocumented marine sink of Cd. Our results suggest that water column oxygen depletion has a substantial impact on Cd biogeochemical cycling, impacting the global relationship between Cd and major nutrients and suggesting that Cd may be a previously unidentified tracer for water column oxygen deficiency on geological timescales. Similar depletions of copper and zinc in the Northeast Pacific indicate that sulfide precipitation in ODZs may also have an influence on the global distribution of other trace metals. PMID:24778239

Undocumented water column sink for cadmium in open ocean oxygen-deficient zones.

PubMed

Janssen, David J; Conway, Tim M; John, Seth G; Christian, James R; Kramer, Dennis I; Pedersen, Tom F; Cullen, Jay T

2014-05-13

Cadmium (Cd) is a micronutrient and a tracer of biological productivity and circulation in the ocean. The correlation between dissolved Cd and the major algal nutrients in seawater has led to the use of Cd preserved in microfossils to constrain past ocean nutrient distributions. However, linking Cd to marine biological processes requires constraints on marine sources and sinks of Cd. Here, we show a decoupling between Cd and major nutrients within oxygen-deficient zones (ODZs) in both the Northeast Pacific and North Atlantic Oceans, which we attribute to Cd sulfide (CdS) precipitation in euxinic microenvironments around sinking biological particles. We find that dissolved Cd correlates well with dissolved phosphate in oxygenated waters, but is depleted compared with phosphate in ODZs. Additionally, suspended particles from the North Atlantic show high Cd content and light Cd stable isotope ratios within the ODZ, indicative of CdS precipitation. Globally, we calculate that CdS precipitation in ODZs is an important, and to our knowledge a previously undocumented marine sink of Cd. Our results suggest that water column oxygen depletion has a substantial impact on Cd biogeochemical cycling, impacting the global relationship between Cd and major nutrients and suggesting that Cd may be a previously unidentified tracer for water column oxygen deficiency on geological timescales. Similar depletions of copper and zinc in the Northeast Pacific indicate that sulfide precipitation in ODZs may also have an influence on the global distribution of other trace metals.

Perils of categorical thinking: "Oxic/anoxic" conceptual model in environmental remediation

USGS Publications Warehouse

Bradley, Paul M.

2012-01-01

Given ambient atmospheric oxygen concentrations of about 21 percent (by volume), the lower limit for reliable quantitation of dissolved oxygen concentrations in groundwater samples is in the range of 0.1–0.5 mg/L. Frameworks for assessing in situ redox condition are often applied using a simple two-category (oxic/anoxic) model of oxygen condition. The "oxic" category defines the environmental range in which dissolved oxygen concentrations are clearly expected to impact contaminant biodegradation, either by supporting aerobic biodegradation of electron-donor contaminants like petroleum hydrocarbons or by inhibiting anaerobic biodegradation of electron-acceptor contaminants like chloroethenes. The tendency to label the second category "anoxic" leads to an invalid assumption that oxygen is insignificant when, in fact, the dissolved oxygen concentration is less than detection but otherwise unknown. Expressing dissolved oxygen concentrations as numbers of molecules per volume, dissolved oxygen concentrations that fall below the 0.1 mg/L field detection limit range from 1 to 1017 molecules/L. In light of recent demonstrations of substantial oxygen-linked biodegradation of chloroethene contaminants at dissolved oxygen concentrations well below the 0.1–0.5 mg/L field detection limit, characterizing "less than detection" oxygen concentrations as "insignificant" is invalid.

Influence of dissolved oxygen concentration on the pharmacokinetics of alcohol in humans.

PubMed

Baek, In-hwan; Lee, Byung-yo; Kwon, Kwang-il

2010-05-01

Ethanol oxidation by the microsomal ethanol oxidizing system requires oxygen for alcohol metabolism, and a higher oxygen uptake increases the rate of ethanol oxidation. We investigated the effect of dissolved oxygen on the pharmacokinetics of alcohol in healthy humans (n = 49). The concentrations of dissolved oxygen were 8, 20, and 25 ppm in alcoholic drinks of 240 and 360 ml (19.5% v/v). Blood alcohol concentrations (BACs) were determined by converting breath alcohol concentrations. Breath samples were collected every 30 min when the BAC was higher than 0.015%, 20 min at BAC < or =0.015%, 10 min at BAC < or =0.010%, and 5 min at BAC < or =0.006%. The high dissolved oxygen groups (20, 25 ppm) descended to 0.000% and 0.050% BAC faster than the normal dissolved oxygen groups (8 ppm; p < 0.05). In analyzing pharmacokinetic parameters, AUC(inf) and K(el) of the high oxygen groups were lower than in the normal oxygen group, while C(max) and T(max) were not significantly affected. In a Monte Carlo simulation, the lognormal distribution of mean values of AUC(inf) and t(1/2) was expected to be reduced in the high oxygen group compared to the normal oxygen group. In conclusion, elevated dissolved oxygen concentrations in alcoholic drinks accelerate the metabolism and elimination of alcohol. Thus, enhanced dissolved oxygen concentrations in alcohol may have a role to play in reducing alcohol-related side effects and accidents.

Oxygen in the Martian atmosphere: Regulation of PO2 by the deposition of iron formations on Mars

NASA Technical Reports Server (NTRS)

Burns, Roger G.

1992-01-01

During Earth's early history, and prior to the evolution of its present day oxygenated atmosphere, extensive iron rich siliceous sedimentary rocks were deposited, consisting of alternating layers of silica (chert) and iron oxide minerals (hematite and magnetite). The banding in iron formations recorded changes of atmosphere-hydrosphere interactions near sea level in the ancient ocean, which induced the oxidation of dissolved ferrous iron, precipitation of insoluble ferric oxides and silica, and regulation of oxygen in Earth's early atmosphere. Similarities between the Archean Earth and the composition of the present day atmosphere on Mars, together with the pervasive presence of ferric oxides in the Martian regolith suggest that iron formation might also have been deposited on Mars and influenced the oxygen content of the Martian atmosphere. Such a possibility is discussed here with a view to assessing whether the oxygen content of the Martian atmosphere has been regulated by the chemical precipitation of iron formations on Mars.

Performance of ANFIS versus MLP-NN dissolved oxygen prediction models in water quality monitoring.

PubMed

Najah, A; El-Shafie, A; Karim, O A; El-Shafie, Amr H

2014-02-01

We discuss the accuracy and performance of the adaptive neuro-fuzzy inference system (ANFIS) in training and prediction of dissolved oxygen (DO) concentrations. The model was used to analyze historical data generated through continuous monitoring of water quality parameters at several stations on the Johor River to predict DO concentrations. Four water quality parameters were selected for ANFIS modeling, including temperature, pH, nitrate (NO3) concentration, and ammoniacal nitrogen concentration (NH3-NL). Sensitivity analysis was performed to evaluate the effects of the input parameters. The inputs with the greatest effect were those related to oxygen content (NO3) or oxygen demand (NH3-NL). Temperature was the parameter with the least effect, whereas pH provided the lowest contribution to the proposed model. To evaluate the performance of the model, three statistical indices were used: the coefficient of determination (R (2)), the mean absolute prediction error, and the correlation coefficient. The performance of the ANFIS model was compared with an artificial neural network model. The ANFIS model was capable of providing greater accuracy, particularly in the case of extreme events.

pH, dissolved oxygen, and adsorption effects on metal removal in anaerobic bioreactors.

PubMed

Willow, Mark A; Cohen, Ronald R H

2003-01-01

Anaerobic bioreactors were used to test the effect of the pH of influent on the removal efficiency of heavy metals from acid-rock drainage. Two studies used a near-neutral-pH, metal-laden influent to examine the heavy metal removal efficiency and hydraulic residence time requirements of the reactors. Another study used the more typical low-pH mine drainage influent. Experiments also were done to (i) test the effects of oxygen content of feed water on metal removal and (ii) the adsorptive capacity of the reactor organic substrate. Analysis of the results indicates that bacterial sulfate reduction may be a zero-order kinetic reaction relative to sulfate concentrations used in the experiments, and may be the factor that controls the metal mass removal efficiency in the anaerobic treatment systems. The sorptive capacities of the organic substrate used in the experiments had not been exhausted during the experiments as indicated by the loading rates of removal of metals exceeding the mass production rates of sulfide. Microbial sulfate reduction was less in the reactors receiving low-pH influent during experiments with short residence times. Sulfate-reducing bacteria may have been inhibited by high flows of low-pH water. Dissolved oxygen content of the feed waters had little effect on sulfate reduction and metal removal capacity.

Predicting the Fate and Effects of Resuspended Metal Contaminated Sediments

DTIC Science & Technology

2015-12-23

force on the sediment. Over the course of the experiment, dissolved and particulate metal concentrations, dissolved oxygen , temperature , turbidity, pH...dissolved oxygen , and temperature . A 16-hour multiple resuspension was also implemented in the SeFEC, intended to replicate intermittent ship traffic...was sampled at the end of hours 4, 8, 12, and 16. Samples were analyzed for: dissolved metals, pH, dissolved oxygen , and temperature (three

Superoxygenated Water as an Experimental Sample for NMR Relaxometry

ERIC Educational Resources Information Center

Nestle, Nikolaus; Dakkouri, Marwan; Rauscher, Hubert

2004-01-01

The increase in NMR relaxation rates as a result of dissolved paramagnetic species on the sample of superoxygenated drinking water is demonstrated. It is concluded that oxygen content in NMR samples is an important issue and can give rise to various problems in the interpretation of both spectroscopic and NMR imaging or relaxation experiments.

An Intelligent Optical Dissolved Oxygen Measurement Method Based on a Fluorescent Quenching Mechanism.

PubMed

Li, Fengmei; Wei, Yaoguang; Chen, Yingyi; Li, Daoliang; Zhang, Xu

2015-12-09

Dissolved oxygen (DO) is a key factor that influences the healthy growth of fishes in aquaculture. The DO content changes with the aquatic environment and should therefore be monitored online. However, traditional measurement methods, such as iodometry and other chemical analysis methods, are not suitable for online monitoring. The Clark method is not stable enough for extended periods of monitoring. To solve these problems, this paper proposes an intelligent DO measurement method based on the fluorescence quenching mechanism. The measurement system is composed of fluorescent quenching detection, signal conditioning, intelligent processing, and power supply modules. The optical probe adopts the fluorescent quenching mechanism to detect the DO content and solves the problem, whereas traditional chemical methods are easily influenced by the environment. The optical probe contains a thermistor and dual excitation sources to isolate visible parasitic light and execute a compensation strategy. The intelligent processing module adopts the IEEE 1451.2 standard and realizes intelligent compensation. Experimental results show that the optical measurement method is stable, accurate, and suitable for online DO monitoring in aquaculture applications.

Distribution and key influential factors of dissolved oxygen off the Changjiang River Estuary (CRE) and its adjacent waters in China.

PubMed

Chi, Lianbao; Song, Xiuxian; Yuan, Yongquan; Wang, Wentao; Zhou, Peng; Fan, Xin; Cao, Xihua; Yu, Zhiming

2017-12-15

Based on two multidisciplinary investigations conducted in summer and winter 2015, the distribution of dissolved oxygen (DO) and the associated seasonal variations off the Changjiang River Estuary (CRE) were studied. The DO content was high in winter, ranging from 6.81-10.29mg/L, and the distribution was mainly controlled by temperature and salinity. The DO concentration was 1.92-9.67mg/L in summer, and a hypoxic zone (DO<3mg/L) covered 14,800km 2 , which was mainly controlled by stratification and organic matter decomposition. The hypoxic zone exhibited a "dual-core" structure and the differences in the biochemical and physical processes between the southern and northern regions were compared: the northern region exhibited stronger pycnocline intensity; while larger biomass and higher TOC as well as TN contents were observed in the southern region. Hypoxia in the northern region might be mainly dominated by stratification, while that in the southern region was mainly associated with organic matter decomposition. Copyright © 2017 Elsevier Ltd. All rights reserved.

Geochemical characterization of shallow ground water in the Eutaw aquifer, Montgomery, Alabama

USGS Publications Warehouse

Robinson, J.L.; Journey, C.A.

2004-01-01

Ground water samples were collected from 30 wells located in, or directly down gradient from, recharge areas of the Eutaw aquifer in Montgomery, Alabama. The major ion content of the water evolves from calcium-sodium-chloride- dominated type in the recharge area to calcium-bicarbonate-dominated type in the confined portion of the aquifer. Ground water in the recharge area was undersaturated with respect to aluminosilicate and carbonate minerals. Ground water in the confined portion of the aquifer was at equilibrium levels for calcite and potassium feldspar. Dissolved oxygen and nitrite-plus-nitrate concentrations decreased as ground water age increased; pH, iron, and sulfate concentrations increased as ground water age increased. Aluminum, copper, and zinc concentrations decreased as ground water age and pH increased. These relations indicate that nitrate, aluminum, copper, and zinc are removed from solution as water moves from recharge areas to the confined areas of the Eutaw aquifer. The natural evolution of ground water quality, which typically increases the pH and decreases the dissolved oxygen content, may be an important limiting factor to the migration of nitrogen based compounds and metals.

An Intelligent Optical Dissolved Oxygen Measurement Method Based on a Fluorescent Quenching Mechanism

PubMed Central

Li, Fengmei; Wei, Yaoguang; Chen, Yingyi; Li, Daoliang; Zhang, Xu

2015-01-01

Dissolved oxygen (DO) is a key factor that influences the healthy growth of fishes in aquaculture. The DO content changes with the aquatic environment and should therefore be monitored online. However, traditional measurement methods, such as iodometry and other chemical analysis methods, are not suitable for online monitoring. The Clark method is not stable enough for extended periods of monitoring. To solve these problems, this paper proposes an intelligent DO measurement method based on the fluorescence quenching mechanism. The measurement system is composed of fluorescent quenching detection, signal conditioning, intelligent processing, and power supply modules. The optical probe adopts the fluorescent quenching mechanism to detect the DO content and solves the problem, whereas traditional chemical methods are easily influenced by the environment. The optical probe contains a thermistor and dual excitation sources to isolate visible parasitic light and execute a compensation strategy. The intelligent processing module adopts the IEEE 1451.2 standard and realizes intelligent compensation. Experimental results show that the optical measurement method is stable, accurate, and suitable for online DO monitoring in aquaculture applications. PMID:26690176

Production of recombinant protein by a novel oxygen-induced system in Escherichia coli.

PubMed

Baez, Antonino; Majdalani, Nadim; Shiloach, Joseph

2014-04-07

The SoxRS regulon of E. coli is activated in response to elevated dissolved oxygen concentration likely to protect the bacteria from possible oxygen damage. The soxS expression can be increased up to 16 fold, making it a possible candidate for recombinant protein expression. Compared with the existing induction approaches, oxygen induction is advantageous because it does not involve addition or depletion of growth factors or nutrients, addition of chemical inducers or temperature changes that can affect growth and metabolism of the producing bacteria. It also does not affect the composition of the growth medium simplifying the recovery and purification processes. The soxS promoter was cloned into the commercial pGFPmut3.1 plasmid creating pAB49, an expression vector that can be induced by increasing oxygen concentration. The efficiency and the regulatory properties of the soxS promoter were characterized by measuring the GFP expression when the culture dissolved oxygen concentration was increased from 30% to 300% air saturation. The expression level of recombinant GFP was proportional to the oxygen concentration, demonstrating that pAB49 is a controllable expression vector. A possible harmful effect of elevated oxygen concentration on the recombinant product was found to be negligible by determining the protein-carbonyl content and its specific fluorescence. By performing high density growth in modified LB medium, the cells were induced by increasing the oxygen concentration. After 3 hours at 300% air saturation, GFP fluorescence reached 109000 FU (494 mg of GFP/L), representing 3.4% of total protein, and the cell concentration reached 29.1 g/L (DW). Induction of recombinant protein expression by increasing the dissolved oxygen concentration was found to be a simple and efficient alternative expression strategy that excludes the use of chemical, nutrient or thermal inducers that have a potential negative effect on cell growth or the product recovery.

Index of stations: surface-water data-collection network of Texas, September 1998

USGS Publications Warehouse

Gandara, Susan C.; Barbie, Dana L.

1999-01-01

As of September 30, 1998, the surface-water data-collection network of Texas (table 1) included 313 continuous-recording streamflow stations (D), 22 gage-height record only stations (G), 23 crest-stage partial-record stations (C), 39 flood-hydrograph partial-record stations (H), 25 low-flow partial-record stations (L), 1 continuous-recording temperature station (M1), 25 continuous-recording temperature and conductivity stations (M2), 3 continuous-recording temperature, conductivity, and dissolved oxygen stations (M3), 13 continuous-recording temperature, conductivity, dissolved oxygen, and pH stations (M4), 5 daily chemical-quality stations (Qd), 133 periodic chemical-quality stations (Qp), 16 reservoir/lake surveys for water quality (Qs), and 70 continuous or daily reservoir-content stations (R). Plate 1 identifies the major river basins in Texas and shows the location of the stations listed in table 1.

Linking microbial community structure to membrane biofouling associated with varying dissolved oxygen concentrations.

PubMed

Gao, Da-wen; Fu, Yuan; Tao, Yu; Li, Xin-xin; Xing, Min; Gao, Xiu-hong; Ren, Nan-qi

2011-05-01

In order to elucidate how dissolved oxygen (DO) concentration influenced the generation of extracellular polymeric substance (EPS) and soluble microbial products (SMP) in mixed liquor and biocake, 16S rDNA fingerprinting analyses were performed to investigate the variation of the microbial community in an aerobic membrane bioreactor (MBR). The function of microbial community structure was proved to be ultimately responsible for biofouling. Obvious microbial community succession from the subphylum of Betaproteobacteria to Deltaproteobacteria was observed in biocake. High concentration of EPS in biocake under the low DO concentration (0.5 mg L(-1)) caused severe biofouling. The correlation coefficient of membrane fouling rate with EPS content in biocake (0.9941-0.9964) was much higher than that in mixed liquor (0.6689-0.8004). Copyright © 2011 Elsevier Ltd. All rights reserved.

Impact of dissolved oxygen concentration on some key parameters and production of rhG-CSF in batch fermentation.

PubMed

Krishna Rao, Dasari V; Ramu, Chatadi T; Rao, Joginapally V; Narasu, Mangamoori L; Bhujanga Rao, Adibhatla Kali S

2008-09-01

The impact of different levels of agitation speed, carbondioxide and dissolved oxygen concentration on the key parameters and production of rhG-CSF in Escherichia coli BL21(DE3)PLysS were studied. Lower carbondioxide concentrations as well as higher agitation speeds and dissolved oxygen concentrations led to reduction in the acetate concentrations, and enhanced the cell growth, but inhibited plasmid stability and rhG-CSF expression. Similarly, higher carbondioxide concentrations and lower agitation speeds as well as dissolved oxygen concentrations led to enhanced acetate concentrations, but inhibited the cell growth and protein expression. To address the bottlenecks, a two-stage agitation control strategy (strategy-1) and two-stage dissolved oxygen control strategy (strategy-2) were employed to establish the physiological and metabolic conditions, so as to improve the expression of rhG-CSF. By adopting strategy-1 the yields were improved 1.4-fold over constant speed of 550 rpm, 1.1-fold over constant dissolved oxygen of 45%, respectively. Similarly, using strategy-2 the yields were improved 1.6-fold over constant speed of 550 rpm, 1.3-fold over constant dissolved oxygen of 45%, respectively.

A Sixteen-year Decline in Dissolved Oxygen in the Central California Current.

PubMed

Ren, Alice S; Chai, Fei; Xue, Huijie; Anderson, David M; Chavez, Francisco P

2018-05-08

A potential consequence of climate change is global decrease in dissolved oxygen at depth in the oceans due to changes in the balance of ventilation, mixing, respiration, and photosynthesis. We present hydrographic cruise observations of declining dissolved oxygen collected along CalCOFI Line 66.7 (Line 67) off of Monterey Bay, in the Central California Current region, and investigate likely mechanisms. Between 1998 and 2013, dissolved oxygen decreased at the mean rate of 1.92 µmol kg -1 year -1 on σ θ 26.6-26.8 kg m -3 isopycnals (250-400 m), translating to a 40% decline from initial concentrations. Two cores of elevated dissolved oxygen decline at 130 and 240 km from shore, which we suggest are a California Undercurrent and a California Current signal respectively, occurred on σ θ ranges of 26.0-26.8 kg m -3 (100-400 m). A box model suggests that small annual changes in dissolved oxygen in source regions are sufficient to be the primary driver of the mid-depth declines. Variation in dissolved oxygen at the bottom of the surface mixed layer suggests that there is also a signal of increased local remineralization.

Numerical Solution of a 3-D Advection-Dispersion Model for Dissolved Oxygen Distribution in Facultative Ponds

NASA Astrophysics Data System (ADS)

Sunarsih; Sasongko, Dwi P.; Sutrisno

2018-02-01

This paper describes a mathematical model for the dissolved oxygen distribution in the plane of a facultative pond with a certain depth. The purpose of this paper is to determine the variation of dissolved oxygen concentration in facultative ponds. The 3-dimensional advection-diffusion equation is solved using the finite difference method Forward Time Central Space (FTCS). Numerical results show that the aerator greatly affects the occurrence of oxygen concentration variations in the facultative pond in the certain depth. The concentration of dissolved oxygen decreases as the depth of the pond increases.

Simulation of hydrodynamics, temperature, and dissolved oxygen in Beaver Lake, Arkansas, 1994-1995

USGS Publications Warehouse

Haggard, Brian; Green, W. Reed

2002-01-01

The tailwaters of Beaver Lake and other White River reservoirs support a cold-water trout fishery of significant economic yield in northwestern Arkansas. The Arkansas Game and Fish Commission has requested an increase in existing minimum flows through the Beaver Lake dam to increase the amount of fishable waters downstream. Information is needed to assess the impact of additional minimum flows on temperature and dissolved-oxygen qualities of reservoir water above the dam and the release water. A two-dimensional, laterally averaged hydrodynamic, thermal and dissolved-oxygen model was developed and calibrated for Beaver Lake, Arkansas. The model simulates surface-water elevation, currents, heat transport and dissolved-oxygen dynamics. The model was developed to assess the impacts of proposed increases in minimum flows from 1.76 cubic meters per second (the existing minimum flow) to 3.85 cubic meters per second (the additional minimum flow). Simulations included assessing (1) the impact of additional minimum flows on tailwater temperature and dissolved-oxygen quality and (2) increasing initial water-surface elevation 0.5 meter and assessing the impact of additional minimum flow on tailwater temperatures and dissolved-oxygen concentrations. The additional minimum flow simulation (without increasing initial pool elevation) appeared to increase the water temperature (<0.9 degrees Celsius) and decrease dissolved oxygen concentration (<2.2 milligrams per liter) in the outflow discharge. Conversely, the additional minimum flow plus initial increase in pool elevation (0.5 meter) simulation appeared to decrease outflow water temperature (0.5 degrees Celsius) and increase dissolved oxygen concentration (<1.2 milligrams per liter) through time. However, results from both minimum flow scenarios for both water temperature and dissolved oxygen concentration were within the boundaries or similar to the error between measured and simulated water column profile values.

How plasma induced oxidation, oxygenation, and de-oxygenation influences viability of skin cells

NASA Astrophysics Data System (ADS)

Oh, Jun-Seok; Strudwick, Xanthe; Short, Robert D.; Ogawa, Kotaro; Hatta, Akimitsu; Furuta, Hiroshi; Gaur, Nishtha; Hong, Sung-Ha; Cowin, Allison J.; Fukuhara, Hideo; Inoue, Keiji; Ito, Masafumi; Charles, Christine; Boswell, Roderick W.; Bradley, James W.; Graves, David B.; Szili, Endre J.

2016-11-01

The effect of oxidation, oxygenation, and de-oxygenation arising from He gas jet and He plasma jet treatments on the viability of skin cells cultured in vitro has been investigated. He gas jet treatment de-oxygenated cell culture medium in a process referred to as "sparging." He plasma jet treatments oxidized, as well as oxygenated or de-oxygenated cell culture medium depending on the dissolved oxygen concentration at the time of treatment. He gas and plasma jets were shown to have beneficial or deleterious effects on skin cells depending on the concentration of dissolved oxygen and other oxidative molecules at the time of treatment. Different combinations of treatments with He gas and plasma jets can be used to modulate the concentrations of dissolved oxygen and other oxidative molecules to influence cell viability. This study highlights the importance of a priori knowledge of the concentration of dissolved oxygen at the time of plasma jet treatment, given the potential for significant impact on the biological or medical outcome. Monitoring and controlling the dynamic changes in dissolved oxygen is essential in order to develop effective strategies for the use of cold atmospheric plasma jets in biology and medicine.

Rapid depletion of dissolved oxygen in 96-well microtiter plate Staphylococcus epidermidis biofilm assays promotes biofilm development and is influenced by inoculum cell concentration.

PubMed

Cotter, John J; O'Gara, James P; Casey, Eoin

2009-08-01

Biofilm-related research using 96-well microtiter plates involves static incubation of plates indiscriminate of environmental conditions, making oxygen availability an important variable which has not been considered to date. By directly measuring dissolved oxygen concentration over time we report here that dissolved oxygen is rapidly consumed in Staphylococcus epidermidis biofilm cultures grown in 96-well plates irrespective of the oxygen concentration in the gaseous environment in which the plates are incubated. These data indicate that depletion of dissolved oxygen during growth of bacterial biofilm cultures in 96-well plates may significantly influence biofilm production. Furthermore higher inoculum cell concentrations are associated with more rapid consumption of dissolved oxygen and higher levels of S. epidermidis biofilm production. Our data reveal that oxygen depletion during bacterial growth in 96-well plates may significantly influence biofilm production and should be considered in the interpretation of experimental data using this biofilm model.

Characterization of water quality and simulation of temperature, nutrients, biochemical oxygen demand, and dissolved oxygen in the Wateree River, South Carolina, 1996-98

USGS Publications Warehouse

Feaster, Toby D.; Conrads, Paul

2000-01-01

In May 1996, the U.S. Geological Survey entered into a cooperative agreement with the Kershaw County Water and Sewer Authority to characterize and simulate the water quality in the Wateree River, South Carolina. Longitudinal profiling of dissolved-oxygen concentrations during the spring and summer of 1996 revealed dissolved-oxygen minimums occurring upstream from the point-source discharges. The mean dissolved-oxygen decrease upstream from the effluent discharges was 2.0 milligrams per liter, and the decrease downstream from the effluent discharges was 0.2 milligram per liter. Several theories were investigated to obtain an improved understanding of the dissolved-oxygen dynamics in the upper Wateree River. Data suggest that the dissolved-oxygen concentration decrease is associated with elevated levels of oxygen-consuming nutrients and metals that are flowing into the Wateree River from Lake Wateree. Analysis of long-term streamflow and water-quality data collected at two U.S. Geological Survey gaging stations suggests that no strong correlation exists between streamflow and dissolved-oxygen concentrations in the Wateree River. However, a strong negative correlation does exist between dissolved-oxygen concentrations and water temperature. Analysis of data from six South Carolina Department of Health and Environmental Control monitoring stations for 1980.95 revealed decreasing trends in ammonia nitrogen at all stations where data were available and decreasing trends in 5-day biochemical oxygen demand at three river stations. The influence of various hydrologic and point-source loading conditions on dissolved-oxygen concentrations in the Wateree River were determined by using results from water-quality simulations by the Branched Lagrangian Transport Model. The effects of five tributaries and four point-source discharges were included in the model. Data collected during two synoptic water-quality samplings on June 23.25 and August 11.13, 1997, were used to calibrate and validate the Branched Lagrangian Transport Model. The data include dye-tracer concentrations collected at six locations, stream-reaeration data collected at four locations, and water-quality and water-temperature data collected at nine locations. Hydraulic data for the Branched Lagrangian Transport Model were simulated by using the U.S. Geological Survey BRANCH one-dimensional, unsteady-flow model. Data that were used to calibrate and validate the BRANCH model included time-series of water-level and streamflow data at three locations. The domain of the hydraulic model and the transport model was a 57.3- and 43.5-mile reach of the river, respectively. A sensitivity analysis of the simulated dissolved-oxygen concentrations to model coefficients and data inputs indicated that the simulated dissolved-oxygen concentrations were most sensitive to changes in the boundary concentration inputs of water temperature and dissolved oxygen followed by sensitivity to the change in streamflow. A 35-percent increase in streamflow resulted in a negative normalized sensitivity index, indicating a decrease in dissolved-oxygen concentrations. The simulated dissolved-oxygen concentrations showed no significant sensitivity to changes in model input rate kinetics. To demonstrate the utility of the Branched Lagrangian Transport Model of the Wateree River, the model was used to simulate several hydrologic and water-quality scenarios to evaluate the effects on simulated dissolved-oxygen concentrations. The first scenario compared the 24-hour mean dissolved-oxygen concentrations for August 13, 1997, as simulated during the model validation, with simulations using two different streamflow patterns. The mean streamflow for August 13, 1997, was 2,000 cubic feet per second. Simulations were run using mean streamflows of 1,000 and 1,400 cubic feet per second while keeping the water-quality boundary conditions the same as were used during the validation simulations. When compared t

Integrated optical sensing of dissolved oxygen in microtiter plates: a novel tool for microbial cultivation.

PubMed

John, Gernot T; Klimant, Ingo; Wittmann, Christoph; Heinzle, Elmar

2003-03-30

Microtiter plates with integrated optical sensing of dissolved oxygen were developed by immobilization of two fluorophores at the bottom of 96-well polystyrene microtiter plates. The oxygen-sensitive fluorophore responded to dissolved oxygen concentration, whereas the oxygen-insensitive one served as an internal reference. The sensor measured dissolved oxygen accurately in optically well-defined media. Oxygen transfer coefficients, k(L)a, were determined by a dynamic method in a commercial microtiter plate reader with an integrated shaker. For this purpose, the dissolved oxygen was initially depleted by the addition of sodium dithionite and, by oxygen transfer from air, it increased again after complete oxidation of dithionite. k(L)a values in one commercial reader were about 10 to 40 h(-1). k(L)a values were inversely proportional to the filling volume and increased with increasing shaking intensity. Dissolved oxygen was monitored during cultivation of Corynebacterium glutamicum in another reader that allowed much higher shaking intensity. Growth rates determined from optical density measurement were identical to those observed in shaking flasks and in a stirred fermentor. Oxygen uptake rates measured in the stirred fermentor and dissolved oxygen concentrations measured during cultivation in the microtiter plate were used to estimate k(L)a values in a 96-well microtiter plate. The resulting values were about 130 h(-1), which is in the lower range of typical stirred fermentors. The resulting maximum oxygen transfer rate was 26 mM h(-1). Simulations showed that the errors caused by the intermittent measurement method were insignificant under the prevailing conditions. Copyright 2003 Wiley Periodicals, Inc. Biotechnol Bioeng 81: 829-836, 2003.

Influence of dissolved gases and heat treatments on the oxidative degradation of polyunsaturated fatty acids enriched dairy beverage.

PubMed

Giroux, Hélène J; Acteau, Geneviève; Sabik, Hassan; Britten, Michel

2008-07-23

The combined effect of dissolved gas composition and heat treatment on the oxidative degradation of a dairy beverage enriched with 2% linseed oil was studied. The dairy beverage was saturated with air, nitrogen, or a nitrogen/hydrogen mixture (4% hydrogen) before pasteurization or sterilization. Saturation with either nitrogen or a nitrogen/hydrogen mixture decreased the dissolved oxygen concentration in dairy beverages (Delta = 7.7 ppm), and the presence of hydrogen significantly reduced the redox potential (Delta = 287 mV). Heat treatments also reduced the oxygen content and redox potential, sterilization being more effective than pasteurization. Both pasteurization and sterilization induced the oxidative degradation of the beverages. On average, the propanal concentration increased by a factor of 2.3 after pasteurization and by a factor of 6.2 after sterilization. However, during storage, sterilized beverages resisted light-induced oxidation better than unheated or pasteurized beverages. Furthermore, saturation with nitrogen or a nitrogen/hydrogen mixture significantly reduced oxidative degradation and provided some protection against color changes during storage.

Dissolved Oxygen Data for Coos Estuary (Oregon)

EPA Science Inventory

The purpose of this product is the transmittal of dissolved oxygen data collected in the Coos Estuary, Oregon to Ms. Molly O'Neill (University of Oregon), for use in her studies on the factors influencing spatial and temporal patterns in dissolved oxygen in this estuary. These d...

Total dissolved gas, barometric pressure, and water temperature data, lower Columbia River, Oregon and Washington, 1996

USGS Publications Warehouse

Tanner, Dwight Q.; Harrison, Howard E.; McKenzie, Stuart W.

1996-01-01

Increased levels of total dissolved gas pressure can cause gas-bubble trauma in fish downstream from dams on the Columbia River. In cooperation with the U.S. Army Corps of Engineers, the U.S. Geological Survey collected data on total dissolved gas pressure, barometric pressure, water temperature, and dissolved oxygen pressure at 11 stations on the lower Columbia River from the John Day forebay (river mile 215.6) to Wauna Mill (river mile 41.9) from March to September 1996. Methods of data collection, review, and processing are described in this report. Summaries of daily minimum, maximum, and mean hourly values are presented for total dissolved gas pressure, barometric pressure, and water temperature. Hourly values for these parameters are presented graphically. Dissolved oxygen data are not presented in this report because the quality-control data show that the data have poor precision and high bias. Suggested changes to monitoring procedures for future studies include (1) improved calibration procedures for total dissolved gas and dissolved oxygen to better define accuracy at elevated levels of supersaturation and (2) equipping dissolved oxygen sensors with stirrers because river velocities at the shoreline monitoring stations probably cannot maintain an adequate flow of water across the membrane surface of the dissolved oxygen sensor.

Field comparison of optical and clark cell dissolved-oxygen sensors

USGS Publications Warehouse

Fulford, J.M.; Davies, W.J.; Garcia, L.

2005-01-01

Three multi-parameter water-quality monitors equipped with either Clark cell type or optical type dissolved-oxygen sensors were deployed for 30 days in a brackish (salinity <10 parts per thousand) environment to determine the sensitivity of the sensors to biofouling. The dissolved-oxygen sensors compared periodically to a hand-held dissolved oxygen sensor, but were not serviced or cleaned during the deployment. One of the Clark cell sensors and the optical sensor performed similarly during the deployment. The remaining Clark cell sensor was not aged correctly prior to deployment and did not perform as well as the other sensors. All sensors experienced substantial biofouling that gradually degraded the accuracy of the dissolved-oxygen measurement during the last half of the deployment period. Copyright ASCE 2005.

Topical dissolved oxygen penetrates skin: model and method.

PubMed

Roe, David F; Gibbins, Bruce L; Ladizinsky, Daniel A

2010-03-01

It has been commonly perceived that skin receives its oxygen supply from the internal circulation. However, recent investigations have shown that a significant amount of oxygen may enter skin from the external overlying surface. A method has been developed for measuring the transcutaneous penetration of human skin by oxygen as described herein. This method was used to determine both the depth and magnitude of penetration of skin by topically applied oxygen. An apparatus consisting of human skin samples interposed between a topical oxygen source and a fluid filled chamber that registered changes in dissolved oxygen. Viable human skin samples of variable thicknesses with and without epidermis were used to evaluate the depth and magnitude of oxygen penetration from either topical dissolved oxygen (TDO) or topical gaseous oxygen (TGO) devices. This model effectively demonstrates transcutaneous penetration of topically applied oxygen. Topically applied dissolved oxygen penetrates through >700 microm of human skin. Topically applied oxygen penetrates better though dermis than epidermis, and TDO devices deliver oxygen more effectively than TGO devices. Copyright (c) 2010 Elsevier Inc. All rights reserved.

The role of reactive oxygen species in the degradation of lignin derived dissolved organic matter

NASA Astrophysics Data System (ADS)

Waggoner, Derek C.; Wozniak, Andrew S.; Cory, Rose M.; Hatcher, Patrick G.

2017-07-01

Evidence suggests that reactive oxygen species (ROS) are important in transforming the chemical composition of the large pool of terrestrially-derived dissolved organic matter (DOM) exported from land to water annually. However, due to the challenges inherent in isolating the effects of individual ROS on DOM composition, the role of ROS in the photochemical alteration of DOM remains poorly characterized. In this work, terrestrial DOM was independently exposed to singlet oxygen (1O2), and superoxide (O2-rad under controlled laboratory conditions). Using ultra-high resolution mass spectrometry to track molecular level alterations of DOM by ROS, these findings suggest exposure to 1O2 (generated using Rose Bengal and visible light) removed formulas with an O/C > 0.3, and primarily resulted in DOM comprised of formulas with higher oxygen content, while O2-rad exposure (from KO2 in DMSO) removed formulas with O/C < 0.3 and produced aliphatic formulas (H/C > 1.5). Comparison of DOM altered by ROS in this study to riverine and coastal DOM showed that (20-80%) overlap in formulas, providing evidence for the role of ROS in shaping the composition of DOM exported from rivers to oceans.

Effects of temperature and dissolved oxygen on Se(IV) removal and Se(0) precipitation by Shewanella sp. HN-41.

PubMed

Lee, Ji-Hoon; Han, Jaehong; Choi, Heechul; Hur, Hor-Gil

2007-08-01

Facultative anaerobic Shewanella sp. strain HN-41 was able to utilize selenite (Se(IV)) as a sole electron acceptor for respiration in anaerobic condition, resulting in reduction of Se(IV) and then precipitation of elemental Se nano-sized spherical particles, which were identified using energy-dispersive X-ray spectroscopy and X-ray absorption near-edge structure spectroscopy. When the effects on Se(IV) reduction to elemental Se were studied by varying incubation temperatures and dissolved oxygen contents, Se(IV) reduction occurred more actively with higher removal rate of Se(IV) in aqueous phase and well-shaped spherical Se(0) nanoparticles were formed from the incubations under N(2) (100%) or N(2):O(2) (80%:20%) at 30 degrees C with average diameter values of 181+/-40 nm and 164+/-24 nm, respectively, while relatively less amounts of irregular-shaped Se(0) nanoparticles were produced with negligible amount of Se(IV) reduction and removal under 100% of O(2). The Se particle size distributions based on scanning electron microscopy also showed a general tendency towards decreased Se particle size as oxygen content increased, whereas the particle size seemed uncorrelated to the change in the incubation temperature. These results also suggest that the size-controlled biological Se(0) nanospheres production may be achieved simply by changing the culture conditions.

Physical and chemical characteristics of water from the hydrographic basin of the Poxim River, Sergipe State, Brazil.

PubMed

de Aguiar Netto, Antenor Oliveira; Garcia, Carlos Alexandre Borges; Hora Alves, José do Patrocínio; Ferreira, Robério Anastácio; Gonzaga da Silva, Marinoé

2013-05-01

The Poxim River is one of Sergipe State's major waterways. It supplies water to the State capital, Aracaju, but is threatened by urban and agricultural developments that compromise both the quantity and the quality of the water. This has direct impacts on the daily lives of the region's population. In this work, a multivariate analytical approach was used to investigate the physical and chemical characteristics of the water in the river basin. Four sampling campaigns were undertaken, in November 2005, and in February, May, and September 2006, at 15 sites distributed along the Poxim. The parameters analyzed were conductivity, turbidity, color, total dissolved solids, dissolved oxygen, alkalinity, hardness, chlorophyll-a, and nutrients (total phosphorus, dissolved orthophosphate, nitrite, nitrate, ammoniacal nitrogen, and total nitrogen). Dissolved oxygen contents were very low in the Poxim-Açu River (1.0-2.8), the Poxim River (1.6-4.6), and the estuarine region (1.7-5.1), due to the dumping of wastes and discharges of domestic and industrial effluents containing organic matter into fluvial and estuarine regions of the Poxim. Factor analysis identified five components that were indicative of the quality of the water, and that explained 81.73 % of the total variance.

Effect of surface hydrophobicity on the formation and stability of oxygen nanobubbles.

PubMed

Pan, Gang; Yang, Bo

2012-06-04

The formation mechanism of a nanoscale gas state is studied on inorganic clay surfaces modified with hexamethyldisilazane, which show different contact angles in ethanol-water solutions. As the dissolved oxygen becomes oversaturated due to the decrease in ethanol-water ratio, oxygen nanoscale gas state are formed and stabilized on the hydrophobic surfaces so that the total oxygen content in the suspension is increased compared to the control solution without the particles. However, the total oxygen content in the suspension with hydrophilic surfaces is lower than the control solution without the particles because the hydrophilic particle surfaces destabilize the nanobubbles on the surfaces by spreading and coagulating them into microbubbles that quickly escape from the suspension solution. No significant correlation was observed between the nanobubble formation and the shape or roughness of the surfaces. Our results suggest that a nanoscale gas state can be formed on both hydrophobic and hydrophilic particle surfaces, but that the stability of the surface nanoscale gas state can vary greatly depending on the hydrophobicity of the solid surfaces. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Quality of water in Luxapallia Creek at Columbus, Mississippi

USGS Publications Warehouse

Kalkhoff, Stephen J.

1982-01-01

The results of a water quality study of a short reach of Luxapallila Creek at Columbus, Mississippi, during September 9-12, 1979, indicate that the water is colored (60 units) and has a low dissolved solids content (44 mg/L). The dissolved oxygen concentration, temperature, and pH of the water in Luxapallila Creek changed a slightly downstream through the study reach. The mean specific conductance almost doubled and the five-day biochemical oxygen demand load increased over four times through the study reach. The fecal coliform to fecal streptococcus ration of 3 to 5 samples collected at the downstream site was greater than 4.0, strongly suggesting the presence of human waste. The concentrations of iron and manganese at the downstream site exceeded the U.S. Environmental Protection Agency 's criteria for domestic water supplies. High concentrations of iron, manganese, and lead also were present in a bottom material sample at the downstream site. (USGS)

Effect of static magnetic field on the oxygen production of Scenedesmus obliquus cultivated in municipal wastewater.

PubMed

Tu, Renjie; Jin, Wenbiao; Xi, Tingting; Yang, Qian; Han, Song-Fang; Abomohra, Abd El-Fatah

2015-12-01

Algal-bacterial symbiotic system, with biological synergism of physiological functions of both algae and bacteria, has been proposed for cultivation of microalgae in municipal wastewater for biomass production and wastewater treatment. The algal-bacterial symbiotic system can enhance dissolved oxygen production which enhances bacterial growth and catabolism of pollutants in wastewater. Therefore, the oxygen production efficiency of microalgae in algal-bacterial systems is considered as the key factor influencing the wastewater treatment efficiency. In the present study, we have proposed a novel approach which uses static magnetic field to enhance algal growth and oxygen production rate with low operational cost and non-toxic secondary pollution. The performance of oxygen production with the magnetic field was evaluated using Scenedesmus obliquus grown in municipal wastewater and was calculated based on the change in dissolved oxygen concentration. Results indicated that magnetic treatment stimulates both algal growth and oxygen production. Application of 1000 GS of magnetic field once at logarithmic growth phase for 0.5 h increased the chlorophyll-a content by 11.5% over the control after 6 days of growth. In addition, magnetization enhanced the oxygen production rate by 24.6% over the control. Results of the study confirmed that application of a proper magnetic field could reduce the energy consumption required for aeration during the degradation of organic matter in municipal wastewater in algal-bacterial symbiotic systems. Copyright © 2015 Elsevier Ltd. All rights reserved.

76 FR 76161 - Clean Water Act Section 303(d): Availability of Three Total Maximum Daily Loads (TMDLs) in Louisiana

Federal Register 2010, 2011, 2012, 2013, 2014

2011-12-06

... Ponchatoula Creek and Dissolved Ponchatoula River. oxygen. 041201 Bayou Labranche-- Dissolved Headwaters to Lake oxygen. Pontchartrain (Scenic) (Estuarine). 041805 Lake Borgne Canal (Violet Dissolved Canal)--MS River siphon oxygen. at Violet to Bayou Dupre (Scenic) (Estuarine). The EPA requests the public provide...

Assessing the Effects of Water Rights Purchases on Dissolved Oxygen, Stream Temperatures, and Fish Habitat

NASA Astrophysics Data System (ADS)

Mouzon, N. R.; Null, S. E.

2014-12-01

Human impacts from land and water development have degraded water quality and altered the physical, chemical, and biological integrity of Nevada's Walker River. Reduced instream flows and increased nutrient concentrations affect native fish populations through warm daily stream temperatures and low nightly dissolved oxygen concentrations. Water rights purchases are being considered to maintain instream flows, improve water quality, and enhance habitat for native fish species, such as Lahontan cutthroat trout. This study uses the River Modeling System (RMSv4), an hourly, physically-based hydrodynamic and water quality model, to estimate streamflows, temperatures, and dissolved oxygen concentrations in the Walker River. We simulate thermal and dissolved oxygen changes from increased streamflow to prioritize the time periods and locations that water purchases most enhance native trout habitat. Stream temperatures and dissolved oxygen concentrations are proxies for trout habitat. Monitoring results indicate stream temperature and dissolved oxygen limitations generally exist in the 115 kilometers upstream of Walker Lake (about 37% of the study area) from approximately May through September, and this reach currently acts as a water quality barrier for fish passage.

Long-period variability of oxygen dissolved in Black Sea waters

NASA Astrophysics Data System (ADS)

Polonsky, A. B.; Kotolypova, A. A.

2017-09-01

Using an archival database from the Institute of Natural and Technical Systems, the low-frequency variability of oxygen dissolved in the deep-water and northwestern parts of the Black Sea for the period of 1955-2004 is analyzed. The upper mixed layer (UML) is characterized by quasi-periodic variability in the dissolved oxygen concentration in the interdecadal scale. Deeper, a long-term decrease in the oxygen concentration is recorded.

Water quality in the New River from Calexico to the Salton Sea, Imperial County, California

USGS Publications Warehouse

Setmire, James G.

1984-01-01

The New River enters the United States at Calexico, Calif., after it crosses the international boundary. Water-quality data from routine collection indicated that the New River was degraded by high organic and bacterial content. Intensive sampling for chemical and physical constituents and properties of the river was done May 9-13, 1977, to quantify the chemical composition of the water and to identify water-quality problems. Concentrations of total organic carbon in the New River at Calexico ranged from 80 to 161 milligrams per liter and dissolved organic carbon ranged from 34 to 42 milligrams per liter; the maximum chemical oxygen demand was 510 milligrams per liter. Intensive sampling for chemical and biological characteristics was done in the New River from May 1977 to June 1978 to determine the occurrence of the organic material and its effects on downstream water quality. Dissolved-oxygen concentration was measured along longitudinal profiles of the river from Calexico to the Salton Sea. A dissolved-oxygen sag downstream from the Calexico gage varied seasonally. The sag extended farther downstream and had lower concentrations of dissolved oxygen during the summer months than during the winter months. The sag of zero dissolved-oxygen concentration extended 26 miles in July 1977. In December 1976, the sag extended 20 miles but the minimum dissolved-oxygen concentration was 2.5 milligrams per liter. The greatest diel (24-hour) variation in dissolved-oxygen concentration occurred in the reach from the Calexico gage to Lyons Crossing, 8.8 miles downstream. High concentrations of organic material were detected as far as Highway 80, 19.5 miles downstream from the international boundary. Biological samples analyzed for benthic invertebrates showed that water at the Calexico and Lyons Crossing sites, nearest the international boundary, was of such poor quality that very few bottom-dwelling organisms could survive. Although the water was of poor quality at Keystone Road, 36 miles downstream, it was able to support a benthic community. The April sample had more than 9,150 organisms on a multiplate sampler, 8,770 of which were of one species. Farther downstream at the Westmorland gage, the water quality, as indicated by the number and diversity of organisms, had improved over that at the Keystone site. The Alamo River at its outlet to the Salton Sea--the control site--had the greatest diversity of all the study sites. This diversity, when compared with the diversity at the Westmorland gage, indicated that the effects of the degraded water quality observed at the New River at Calexico are detected as far as 62 miles downstream. Standard bacteria indicator tests indicate that fecal contamination exists in the New River. Counts of fecal coliform bacteria ranged from 180,000 to 2,800,000 colonies per 100 milliliters for the 20-mile reach from Calexico to Highway 80, and fecal streptococcal bacteria ranged from 5,000 to 240,000 colonies per 100 milliliters.

Water Quality Conditions in Upper Klamath and Agency Lakes, Oregon, 2005

USGS Publications Warehouse

Hoilman, Gene R.; Lindenberg, Mary K.; Wood, Tamara M.

2008-01-01

During June-October 2005, water quality data were collected from Upper Klamath and Agency Lakes in Oregon, and meteorological data were collected around and within Upper Klamath Lake. Data recorded at two continuous water quality monitors in Agency Lake showed similar temperature patterns throughout the field season, but data recorded at the northern site showed more day-to-day variability for dissolved oxygen concentration and saturation after late June and more day-to-day variability for pH and specific conductance values after mid-July. Data recorded from the northern and southern parts of Agency Lake showed more comparable day-to-day variability in dissolved oxygen concentrations and pH from September through the end of the monitoring period. For Upper Klamath Lake, seasonal (late July through early August) lows of dissolved oxygen concentrations and saturation were coincident with a seasonal low of pH values and seasonal highs of ammonia and orthophosphate concentrations, specific conductance values, and water temperatures. Patterns in these parameters, excluding water temperature, were associated with bloom dynamics of the cyanobacterium (blue-green alga) Aphanizomenon flos-aquae in Upper Klamath Lake. In Upper Klamath Lake, water temperature in excess of 28 degrees Celsius (a high stress threshold for Upper Klamath Lake suckers) was recorded only once at one site during the field season. Large areas of Upper Klamath Lake had periods of dissolved oxygen concentration of less than 4 milligrams per liter and pH value greater than 9.7, but these conditions were not persistent throughout days at most sites. Dissolved oxygen concentrations in Upper Klamath Lake on time scales of days and months appeared to be influenced, in part, by bathymetry and prevailing current flow patterns. Diel patterns of water column stratification were evident, even at the deepest sites. This diel pattern of stratification was attributable to diel wind speed patterns and the shallow nature of most of Upper Klamath Lake. Timing of the daily extreme values of dissolved oxygen concentration, pH, and water temperature was less distinct with increased water column depth. Chlorophyll a concentrations varied spatially and temporally throughout Upper Klamath Lake. Location greatly affected algal concentrations, in turn affecting nutrient and dissolved oxygen concentrations - some of the highest chlorophyll a concentrations were associated with the lowest dissolved oxygen concentrations and the highest un-ionized ammonia concentrations. The occurrence of the low dissolved oxygen and high un-ionized ammonia concentrations coincided with a decline in algae resulting from cell death, as measured by concentrations of chlorophyll a. Dissolved oxygen production rates in experiments were as high as 1.47 milligrams of oxygen per liter per hour, and consumption rates were as much as -0.73 milligrams of oxygen per liter per hour. Dissolved oxygen consumption rates measured in this study were comparable to those measured in a 2002 Upper Klamath Lake study, and a higher rate of dissolved oxygen consumption was recorded in dark bottles positioned higher in the water column. Data, though inconclusive, indicated that a decreasing trend of dissolved oxygen productivity through July could have contributed to the decreasing dissolved oxygen concentrations and percent saturation recorded in Upper Klamath Lake during this time. Phytoplankton self-shading was evident from a general inverse relation between depth of photic zone and chlorophyll a concentrations. This shading caused net dissolved oxygen consumption during daylight hours in lower parts of the water column that would otherwise have been in the photic zone. Meteorological data collected in and around Upper Klamath Lake showed that winds were likely to come from a broad range of westerly directions in the northern one-third of the lake, but tended to come from a narrow range of northwesterly directions

Relation between flows and dissolved oxygen in the Roanoke River between Roanoke Rapids Dam and Jamesville, North Carolina, 2005-2009

USGS Publications Warehouse

Wehmeyer, Loren L.; Wagner, Chad R.

2011-01-01

The relation between dam releases and dissolved-oxygen concentration, saturation and deficit, downstream from Roanoke Rapids Dam in North Carolina was evaluated from 2005 to 2009. Dissolved-oxygen data collected at four water-quality monitoring stations downstream from Roanoke Rapids Dam were used to determine if any statistical relations or discernible quantitative or qualitative patterns linked Roanoke River in-stream dissolved-oxygen levels to hydropower peaking at Roanoke Rapids Dam. Unregulated tributaries that inundate and drain portions of the Roanoke River flood plain are crucial in relation to in-stream dissolved oxygen. Hydropower peaking from 2005 to 2009 both inundated and drained portions of the flood plain independently of large storms. The effects of these changes in flow on dissolved-oxygen dynamics are difficult to isolate, however, because of (1) the variable travel time for water to move down the 112-mile reach of the Roanoke River from Roanoke Rapids Dam to Jamesville, North Carolina, and (2) the range of in-situ conditions, particularly inundation history and water temperature, in the flood plain. Statistical testing was conducted on the travel-time-adjusted hourly data measured at each of the four water-quality stations between May and November 2005-2009 when the weekly mean flow was 5,000-12,000 cubic feet per second (a range when Roanoke Rapids Dam operations likely affect tributary and flood-plain water levels). Results of this statistical testing indicate that at the 99-percent confidence interval dissolved-oxygen levels downstream from Roanoke Rapids Dam were lower during peaking weeks than during non-peaking weeks in three of the five years and higher in one of the five years; no data were available for weeks with peaking in 2007. For the four years of statistically significant differences in dissolved oxygen between peaking and non-peaking weeks, three of the years had statistically signficant differences in water temperature. Years with higher water temperature during peaking had lower dissolved oxygen during peaking. Only 2009 had no constistent statistically significant water-temperature difference at all sites, and dissolved-oxygen levels downstream from Roanoke Rapids Dam during peaking weeks that year were lower than during non-peaking weeks. Between 2005 and 2009, daily mean dissolved-oxygen concentrations below the State standard occurred during only 1 of the 17 (6 percent) peaking weeks, with no occurrence of instantaneous dissolved-oxygen concentrations below the State standard. This occurrence was during a 9-day period in July 2005 when the daily maximum air temperatures approached or exceeded 100 degrees Fahrenheit, and the draining of the flood plains from peaking operations was followed by consecutive days of low flows.

Effects of exposure to agricultural drainage ditch water on survivorship, distribution, and abundnance of riffle beetles (Coleoptera: Elmidae) in headwater streams of the Cedar Creek watershed, Indiana

USDA-ARS?s Scientific Manuscript database

Riffle Beetles (Coleoptera: Elmidae) require very good water quality, mature streams with riffle habitat, and high dissolved oxygen content. As such, they prove to be good indicators of ecological health in agricultural headwater streams. We conducted static renewal aquatic bioassays using water fro...

The response of virally infected insect cells to dissolved oxygen concentration: recombinant protein production and oxidative damage.

PubMed

Saarinen, Mark A; Murhammer, David W

2003-01-05

The effects of dissolved oxygen (DO) concentration on virally infected insect cells were investigated in 3-L bioreactor culture. Specifically, cultures of Spodoptera frugiperda Sf-9 (Sf-9) and Trichoplusia ni BTI-Tn-5B1-4 (Tn-5B1-4) were infected with Autographa californica multiple nucleopolyhedrovirus expressing secreted alkaline phosphatase (SEAP). Following infection at a DO concentration of 50% air saturation, the DO concentration was adjusted to a final value of either 190%, 50%, or 10% air saturation. Recombinant SEAP production, cell viability, protein carbonyl content, and thiobarbituric acid reactive substances (TBARS) content were monitored. The increases in protein carbonyl and TBARS contents are taken to be indicators of protein oxidation and lipid oxidation, respectively. DO concentration was found to have no noticeable effect on SEAP production or cell viability decline in the Sf-9 cell line. In the Tn-5B1-4 cell line, cells displayed an increased peak SEAP production rate for 190% air saturation and displayed an increased rate of viability decline at increased DO concentration. Protein carbonyl content showed no significant increase in the Sf-9 cell line by 72 h postinfection (pi) at any DO concentration but showed a twofold increase at 10% and 50% DO concentration and a threefold increase at 190% DO concentration by 72 h pi in Tn-5B1-4 cells. TBARS content was found to increase by approximately 50% in Sf-9 cells and by approximately twofold in Tn-5B1-4 cells by 72 h pi with no clear relationship to DO concentration. It is hypothesized that oxygen uptake changes due to the viral infection process may bear a relation to the observed increases in protein and lipid oxidation and that lipid oxidation may play an important role in the death of virally infected insect cells. Copyright 2002 Wiley Periodicals, Inc.

Indicators: Dissolved Oxygen

EPA Pesticide Factsheets

Dissolved oxygen (DO) is the amount of oxygen that is present in water. It is an important measure of water quality as it indicates a water body's ability to support aquatic life. Water bodies receive oxygen from the atmosphere and from aquatic plants.

Mapping tissue oxygen in vivo by photoacoustic lifetime imaging

NASA Astrophysics Data System (ADS)

Shao, Qi; Morgounova, Ekaterina; Choi, Jeung-Hwan; Jiang, Chunlan; Bischof, John; Ashkenazi, Shai

2013-03-01

Oxygen plays a key role in the energy metabolism of living organisms. Any imbalance in the oxygen levels will affect the metabolic homeostasis and lead to pathophysiological diseases. Hypoxia, a status of low tissue oxygen, is a key factor in tumor biology as it is highly prominent in tumor tissues. However, clinical tools for assessing tissue oxygenation are limited. The gold standard is polarographic needle electrode which is invasive and not capable of mapping (imaging) the oxygen content in tissue. We applied the method of photoacoustic lifetime imaging (PALI) of oxygen-sensitive dye to small animal tissue hypoxia research. PALI is new technology for direct, non-invasive imaging of oxygen. The technique is based on mapping the oxygen-dependent transient optical absorption of Methylene Blue (MB) by pump-probe photoacoustic imaging. Our studies show the feasibility of imaging of dissolved oxygen distribution in phantoms. In vivo experiments demonstrate that the hypoxia region is consistent with the site of subcutaneously xenografted prostate tumor in mice with adequate spatial resolution and penetration depth.

Development, calibration, and sensitivity analyses of a high-resolution dissolved oxygen mass balance model for the northern Gulf of Mexico

EPA Science Inventory

A high-resolution dissolved oxygen mass balance model was developed for the Louisiana coastal shelf in the northern Gulf of Mexico. GoMDOM (Gulf of Mexico Dissolved Oxygen Model) was developed to assist in evaluating the impacts of nutrient loading on hypoxia development and exte...

A one-dimensional, steady-state, dissolved-oxygen model and waste-load assimilation study for West Fork Blue River, Washington County, Indiana

USGS Publications Warehouse

Peters, James G.; Wilber, W.G.; Crawford, Charles G.; Girardi, F.P.

1979-01-01

A digital computer model calibrated to observe stream conditions was used to evaluate water quality in West Fork Blue River, Washington County, IN. Instream dissolved-oxygen concentration averaged 96.5% of saturation at selected sites on West Fork Blue River during two 24-hour summer surveys. This high dissolved-oxygen concentration reflects small carbonaceous and nitrogenous waste loads; adequate dilution of waste by the stream; and natural reaeration. Nonpoint source waste loads accounted for an average of 53.2% of the total carbonaceous biochemical-oxygen demand and 90.2% of the nitrogenous biochemical-oxygen demand. Waste-load assimilation was studiedfor critical summer and winter low flows. Natural streamflow for these conditions was zero, so no benefit from dilution was provided. The projected stream reaeration capacity was not sufficient to maintain the minimum daily dissolved-oxygen concentration (5 milligrams per liter) in the stream with current waste-discharge restrictions. During winter low flow, ammonia toxicity, rather than dissolved-oxygen concentration, was the limiting water-quality criterion downstream from the Salem wastewater-treatment facility. (USGS)

Effect of dissolved oxygen and temperature on macromolecular composition and PHB storage of activated sludge.

PubMed

Reyes, Paula; Urtubia, Alejandra; Schiappacasse, María C; Chamy, Rolando; Montalvo, Silvio; Borja, Rafael

2014-01-01

The macromolecular composition of activated sludge (lipids, intracellular proteins and intracellular polysaccharides) was studied together with its capacity to store macromolecules such as polyhydroxybutyrate (PHB) in a conventional activated sludge system fed with synthetic sewage water at an organic load rate of 1.0 kg COD/(m(3)·d), varying the dissolved oxygen (DO) and temperature. Six DO concentrations (0.8, 1.0, 1.5, 2.0, 2.5 and 8 mg/L) were studied at 20°C with a sludge retention time (SRT) of 6 days. In addition, four temperatures (10ºC, 15ºC, 20ºC and 30ºC) were assessed at constant DO (2 mg/L) with 2 days SRT in a second experimental run. The highest lipid content in the activated sludge was 95.6 mg/g VSS, obtained at 30°C, 2 mg/L of DO and a SRT of 2 days. The highest content of intracellular proteins in the activated sludge was 87.8 mg/g VSS, obtained at 20°C, 8 mg/L of DO and a SRT of 6 days. The highest content of intracellular polysaccharides in the activated sludge was 76.6 mg/g VSS, which was achieved at 20°C, a SRT of 6 days and a wide range of DO. The activated sludge PHB storage was very low for all the conditions studied.

Opposite effects of dissolved oxygen on the removal of As(III) and As(V) by carbonate structural Fe(II).

PubMed

Tian, Zeyuan; Feng, Yong; Guan, Yiyi; Shao, Binbin; Zhang, Yalei; Wu, Deli

2017-12-05

Freshly prepared carbonate structural Fe(II) (CSF) was used to immobilize As(III) and As(V) in wastewater under oxic and anoxic conditions. Dissolved oxygen was found to exert opposite effects on these two arsenic species. The sorption density of As(III) was higher under oxic conditions, whereas that of As(V) was higher under anoxic conditions. X-ray diffraction and infrared spectroscopic analyses indicated that crystalline parasymplesite (Fe(II) 3 (AsO 4 ) 2 ·8H 2 O) was formed when As(V) was removed under anoxic conditions, while an amorphous Fe-As-containing precipitate was formed when As(III) was removed under oxic conditions. The distribution of arsenic and iron between the solution and sediments suggested that the oxidation of structural Fe(II) promoted coprecipitation process and inhibited surface complexation. X-ray photoelectron spectroscopic analyses revealed that more As(III) was oxidized under oxic condition, which contributed to a higher sorption capacity for As(III). The formation of parasymplesite through surface complexation/precipitation was proposed to be more effective for the removal of As(V) by CSF, while As(III) was more efficiently removed through coprecipitation. Together, the results suggest that CSF may be an effective material for sequestering both As(III) and As(V). In addition, attention should be paid to the dissolved oxygen content when remediating different arsenic species.

Water masses in the Humboldt Current System: Properties, distribution, and the nitrate deficit as a chemical water mass tracer for Equatorial Subsurface Water off Chile

NASA Astrophysics Data System (ADS)

Silva, Nelson; Rojas, Nora; Fedele, Aldo

2009-07-01

Three sections are used to analyze the physical and chemical characteristics of the water masses in the eastern South Pacific and their distributions. Oceanographic data were taken from the SCORPIO (May-June 1967), PIQUERO (May-June 1969), and KRILL (June 1974) cruises. Vertical sections of temperature, salinity, σ θ, dissolved oxygen, nitrate, nitrite, phosphate, and silicate were used to analyze the water column structure. Five water masses were identified in the zone through T- S diagrams: Subantarctic Water, Subtropical Water, Equatorial Subsurface Water, Antarctic Intermediate Water, and Pacific Deep Water. Their proportions in the sea water mixture are calculated using the mixing triangle method. Vertical sections were used to describe the geographical distributions of the water mass cores in the upper 1500 m. Several characteristic oceanographic features in the study area were analyzed: the shallow salinity minimum displacement towards the equator, the equatorial subsurface salinity maximum associated with a dissolved oxygen minimum zone and a high nutrient content displacement towards the south, and the equatorward intermediate Antarctic salinity minimum associated with a dissolved oxygen maximum. The nitrate deficit generated in the denitrification area off Peru and northern Chile is proposed as a conservative chemical tracer for the Equatorial Subsurface Waters off the coast of Chile, south of 25°S.

Brain tissue oxygen tension is more indicative of oxygen diffusion than oxygen delivery and metabolism in patients with traumatic brain injury.

PubMed

Rosenthal, Guy; Hemphill, J Claude; Sorani, Marco; Martin, Christine; Morabito, Diane; Obrist, Walter D; Manley, Geoffrey T

2008-06-01

Despite the growing clinical use of brain tissue oxygen monitoring, the specific determinants of low brain tissue oxygen tension (P(bt)O2) following severe traumatic brain injury (TBI) remain poorly defined. The objective of this study was to evaluate whether P(bt)O2 more closely reflects variables related to cerebral oxygen diffusion or reflects cerebral oxygen delivery and metabolism. Prospective observational study. Level I trauma center. Fourteen TBI patients with advanced neuromonitoring underwent an oxygen challenge (increase in FiO2 to 1.0) to assess tissue oxygen reactivity, pressure challenge (increase in mean arterial pressure) to assess autoregulation, and CO2 challenge (hyperventilation) to assess cerebral vasoreactivity. None. P(bt)O2 was measured directly with a parenchymal probe in the least-injured hemisphere. Local cerebral blood flow (CBF) was measured with a parenchymal thermal diffusion probe. Cerebral venous blood gases were drawn from a jugular bulb venous catheter. We performed 119 measurements of PaO2, arterial oxygen content (CaO2), jugular bulb venous oxygen tension (PVO2), venous oxygen content (CVO2), arteriovenous oxygen content difference (AVDO2), and local cerebral metabolic rate of oxygen (locCMRO2). In multivariable analysis adjusting for various variables of cerebral oxygen delivery and metabolism, the only statistically significant relationship was that between P(bt)O2 and the product of CBF and cerebral arteriovenous oxygen tension difference (AVTO2), suggesting a strong association between brain tissue oxygen tension and diffusion of dissolved plasma oxygen across the blood-brain barrier. Measurements of P(bt)O2 represent the product of CBF and the cerebral AVTO2 rather than a direct measurement of total oxygen delivery or cerebral oxygen metabolism. This improved understanding of the cerebral physiology of P(bt)O2 should enhance the clinical utility of brain tissue oxygen monitoring in patients with TBI.

Dissolved oxygen analysis, TMDL model comparison, and particulate matter shunting—Preliminary results from three model scenarios for the Klamath River upstream of Keno Dam, Oregon

USGS Publications Warehouse

Sullivan, Annett B.; Rounds, Stewart A.; Deas, Michael L.; Sogutlugil, I. Ertugrul

2012-01-01

Efforts are underway to identify actions that would improve water quality in the Link River to Keno Dam reach of the Upper Klamath River in south-central Oregon. To provide further insight into water-quality improvement options, three scenarios were developed, run, and analyzed using previously calibrated CE-QUAL-W2 hydrodynamic and water-quality models. Additional scenarios are under development as part of this ongoing study. Most of these scenarios evaluate changes relative to a "current conditions" model, but in some cases a "natural conditions" model was used that simulated the reach without the effect of point and nonpoint sources and set Upper Klamath Lake at its Total Maximum Daily Load (TMDL) targets. These scenarios were simulated using a model developed by the U.S. Geological Survey (USGS) and Watercourse Engineering, Inc. for the years 2006–09, referred to here as the "USGS model." Another model of the reach was developed by Tetra Tech, Inc. for years 2000 and 2002 to support the Klamath River TMDL process; that model is referred to here as the "TMDL model." The three scenarios described in this report included (1) an analysis of whether this reach of the Upper Klamath River would be in compliance with dissolved oxygen standards if sources met TMDL allocations, (2) an application of more recent datasets to the TMDL model with comparison to results from the USGS model, and (3) an examination of the effect on dissolved oxygen in the Klamath River if particulate material were stopped from entering Klamath Project diversion canals. Updates and modifications to the USGS model are in progress, so in the future these scenarios will be reanalyzed with the updated model and the interim results presented here will be superseded. Significant findings from this phase of the investigation include: * The TMDL analysis used depth-averaged dissolved oxygen concentrations from model output for comparison with dissolved oxygen standards. The Oregon dissolved oxygen standards do not specify whether the numeric criteria are based on depth-averaged dissolved oxygen concentration; this was an interpretation of the standards rule by the Oregon Department of Environmental Quality (ODEQ). In this study, both depth-averaged and volume-averaged dissolved oxygen concentrations were calculated from model output. Results showed that modeled depth-averaged concentrations typically were lower than volume-averaged dissolved oxygen concentrations because depth-averaging gives a higher weight to small volume areas near the channel bottom that often have lower dissolved oxygen concentrations. Results from model scenarios in this study are reported using volume-averaged dissolved oxygen concentrations. * Under all scenarios analyzed, violations of the dissolved oxygen standard occurred most often in summer. Of the three dissolved oxygen criteria that must be met, the 30-day standard was violated most frequently. Under the base case (current conditions), fewer violations occurred in the upstream part of the reach. More violations occurred in the down-stream direction, due in part to oxygen demand from the decay of algae and organic matter from Link River and other inflows. * A condition in which Upper Klamath Lake and its Link River outflow achieved Upper Klamath Lake TMDL water-quality targets was most effective in reducing the number of violations of the dissolved oxygen standard in the Link River to Keno Dam reach of the Klamath River. The condition in which point and nonpoint sources within the Link River to Keno Dam reach met Klamath River TMDL allocations had no effect on dissolved oxygen compliance in some locations and a small effect in others under current conditions. On the other hand, meeting TMDL allocations for nonpoint and point sources was predicted to be important in meeting dissolved oxygen criteria when Upper Klamath Lake and Link River also met Upper Klamath TMDL water-quality targets. * The location of greatest dissolved oxygen improvement from nutrient and organic matter reductions was downstream from point and nonpoint source inflows because time and distance are required for decay to occur and for oxygen demand to be exerted. * After assessing compliance with dissolved oxygen standards at all 102 model segments in the Link River to Keno Dam reach, it was determined that the seven locations used by ODEQ appear to be a representative subset of the reach for dissolved oxygen analysis. * The USGS and TMDL models were qualitatively compared by running both models for the 2006–09 period but preserving the essential characteristics of each, such as organic matter partitioning, bathymetric representation, and parameter rates. The analysis revealed that some constituents were not greatly affected by the differing algorithms, rates, and assumptions in the two models. Conversely, other constituents, especially organic matter, were simulated differently by the two models. Organic matter in this river system is best represented by a mixture of relatively labile particulate material and a substantial concentration of refractory dissolved material. In addition, the use of a first-order sediment oxygen demand, as in the USGS model, helps to capture the seasonal and dynamic effect of settled organic and algal material. * Simulation of shunting (diverting) particulate material away from the intake of four Klamath Project diversion canals, so that the material stayed in the river and out of the Project area, caused higher concentrations of particulate material to occur in the river. In all cases modeled, the increase in in-river particulate material also produced decreased dissolved oxygen concentrations and an increase in the number of days when dissolved oxygen standards were violated. * If particulate material were shunted back into the river at the Klamath Project diversion canals, less organic matter and nutrients would be taken into the Klamath Project area and the Lost River basin, resulting in return flows to the Klamath River via Lost River Diversion Channel that may have reduced nutrient concentrations. Model scenarios bracketing potential end-member nutrient concentrations showed that the composition of the return flows had little to no effect on dissolved oxygen compliance under simulated conditions.

Passive Biobarrier for Treating Co-mingled Perchlorate and RDX in Groundwater at an Active Range

DTIC Science & Technology

2016-05-12

and Groundwater Temperature ............................. 102 6.1.2 Dissolved Oxygen (DO) and Oxidation Reduction Potential (ORP...22 or equivalent). Parameters, including temperature , conductivity, dissolved oxygen , oxidation-reduction potential (ORP), turbidity, and pH were...3% for temperature and specific conductivity, and ᝺% for dissolved oxygen , ORP, and turbidity. When parameters were stable according to the above

Evaluation of Eurasian Watermilfoil Control Techniques Using Aquatic Herbicides in Fort Peck Lake, Montana

DTIC Science & Technology

2015-07-01

19 Table 3. Temperature , dissolved oxygen , pH, and wind...21 Table 4. Temperature , dissolved oxygen , and pH measured in the study plots following treatment, Fort Peck Lake, MT, 2012...quality, particularly temperature , pH, dissolved oxygen , and nutrient cycling (Prentki et al. 1979; Carpenter and Lodge 1986, Frodge et al. 1990; Boylen

Dissolved oxygen as a key parameter to aerobic granule formation.

PubMed

Sturm, B S McSwain; Irvine, R L

2008-01-01

Much research has asserted that high shear forces are necessary for the formation of aerobic granular sludge in Sequencing Batch Reactors (SBRs). In order to distinguish the role of shear and dissolved oxygen on granule formation, two separate experiments were conducted with three bench-scale SBRs. In the first experiment, an SBR was operated with five sequentially decreasing superficial upflow gas velocities ranging from 1.2 to 0.4 cm s(-1). When less than 1 cm s(-1) shear was applied to the reactor, aerobic granules disintegrated into flocs, with corresponding increases in SVI and effluent suspended solids. However, the dissolved oxygen also decreased from 8 mg L(-1) to 5 mg L(-1), affecting the Feast/Famine regime in the SBR and the substrate removal kinetics. A second experiment operated two SBRs with an identical shear force of 1.2 cm s(-1), but two dissolved oxygen concentrations. Even when supplied a high shear force, aerobic granules could not form at a dissolved oxygen less than 5 mg L(-1), with a Static Fill. These results indicate that the substrate removal kinetics and dissolved oxygen are more significant to granule formation than shear force. Copyright IWA Publishing 2008.

Improved arterial blood oxygenation following intravenous infusion of cold supersaturated dissolved oxygen solution.

PubMed

Grady, Daniel J; Gentile, Michael A; Riggs, John H; Cheifetz, Ira M

2014-01-01

One of the primary goals of critical care medicine is to support adequate gas exchange without iatrogenic sequelae. An emerging method of delivering supplemental oxygen is intravenously rather than via the traditional inhalation route. The objective of this study was to evaluate the gas-exchange effects of infusing cold intravenous (IV) fluids containing very high partial pressures of dissolved oxygen (>760 mm Hg) in a porcine model. Juvenile swines were anesthetized and mechanically ventilated. Each animal received an infusion of cold (13 °C) Ringer's lactate solution (30 mL/kg/hour), which had been supersaturated with dissolved oxygen gas (39.7 mg/L dissolved oxygen, 992 mm Hg, 30.5 mL/L). Arterial blood gases and physiologic measurements were repeated at 15-minute intervals during a 60-minute IV infusion of the supersaturated dissolved oxygen solution. Each animal served as its own control. Five swines (12.9 ± 0.9 kg) were studied. Following the 60-minute infusion, there were significant increases in PaO2 and SaO2 (P < 0.05) and a significant decrease in PaCO2 (P < 0.05), with a corresponding normalization in arterial blood pH. Additionally, there was a significant decrease in core body temperature (P < 0.05) when compared to the baseline preinfusion state. A cold, supersaturated dissolved oxygen solution may be intravenously administered to improve arterial blood oxygenation and ventilation parameters and induce a mild therapeutic hypothermia in a porcine model.

Improved Arterial Blood Oxygenation Following Intravenous Infusion of Cold Supersaturated Dissolved Oxygen Solution

PubMed Central

Grady, Daniel J; Gentile, Michael A; Riggs, John H; Cheifetz, Ira M

2014-01-01

BACKGROUND One of the primary goals of critical care medicine is to support adequate gas exchange without iatrogenic sequelae. An emerging method of delivering supplemental oxygen is intravenously rather than via the traditional inhalation route. The objective of this study was to evaluate the gas-exchange effects of infusing cold intravenous (IV) fluids containing very high partial pressures of dissolved oxygen (>760 mm Hg) in a porcine model. METHODS Juvenile swines were anesthetized and mechanically ventilated. Each animal received an infusion of cold (13 °C) Ringer’s lactate solution (30 mL/kg/hour), which had been supersaturated with dissolved oxygen gas (39.7 mg/L dissolved oxygen, 992 mm Hg, 30.5 mL/L). Arterial blood gases and physiologic measurements were repeated at 15-minute intervals during a 60-minute IV infusion of the supersaturated dissolved oxygen solution. Each animal served as its own control. RESULTS Five swines (12.9 ± 0.9 kg) were studied. Following the 60-minute infusion, there were significant increases in PaO2 and SaO2 (P < 0.05) and a significant decrease in PaCO2 (P < 0.05), with a corresponding normalization in arterial blood pH. Additionally, there was a significant decrease in core body temperature (P < 0.05) when compared to the baseline preinfusion state. CONCLUSIONS A cold, supersaturated dissolved oxygen solution may be intravenously administered to improve arterial blood oxygenation and ventilation parameters and induce a mild therapeutic hypothermia in a porcine model. PMID:25249764

Origin of oxygen in sulfate during pyrite oxidation with water and dissolved oxygen: an in situ horizontal attenuated total reflectance infrared spectroscopy isotope study.

PubMed

Usher, Courtney R; Cleveland, Curtis A; Strongin, Daniel R; Schoonen, Martin A

2004-11-01

FeS2 (pyrite) is known to react with water and dissolved molecular oxygen to form sulfate and iron oxyhydroxides. This process plays a large role in the environmentally damaging phenomenon known as acid mine drainage. An outstanding scientific issue has been whether the oxygen in the sulfate and oxyhydroxide product was derived from water and/or dissolved oxygen. By monitoring the reaction in situ with horizontal attenuated total reflectance infrared spectroscopy, it was found that when using 18O isotopically substituted water, the majority of the infrared absorbance due to sulfate product red-shifted approximately 70 cm(-1) relative to the absorbance of sulfate using H(2)16O as a reactant. Bands corresponding to the iron oxyhydroxide product did not shift. These results indicate water as the primary source of oxygen in the sulfate product, while the oxygen atoms in the iron oxyhydroxide product are obtained from dissolved molecular oxygen.

A one-dimensional, steady-state, dissolved-oxygen model and waste-load assimilation study for East Fork White River, Bartholomew County, Indiana

USGS Publications Warehouse

Wilber, William G.; Peters, James G.; Crawford, Charles G.

1979-01-01

A digital model calibrated to conditions in East Fork White River, Bartholomew County, IN, was used to develop alternatives for future waste loadings that would be compatible with Indiana stream water-quality standards defined for two critical hydrologic conditions, summer and winter low flows. The model indicates that benthic-oxygen demand and the headwater concentrations of carbonaceous biochemical-oxygen demand, nitrogenous biochemical-oxygen demand, and dissolved oxygen are the most significant factors affecting the dissolved-oxygen concentration of East Fork White River downstream from the Columbus wastewater-treatment facility. The effect of effluent from the facility on the water quality of East Fork White River was minimal. The model also indicates that, with a benthic-oxygen demand of approximately 0.65 gram per square meter per day, the stream has no additional waste-load assimilative capacity during summer low flows. Regardless of the quality of the Columbus wastewater effluent, the minimum 24-hour average dissolved-oxygen concentration of at least 5 milligrams per liter, the State 's water-quality standard for streams, would not be met. Ammonia toxicity is not a limiting water-quality criterion during summer and winter low flows. During winter low flows, the current carbonaceous biochemical-oxygen demand limits for the Columbus wastewater-treatment facility will not result in violations of the in-stream dissolved-oxygen standard. (USGS)

Singlet oxygen in the coupled photochemical and biochemical oxidation of dissolved organic matter.

PubMed

Cory, Rose M; McNeill, Kristopher; Cotner, James P; Amado, Andre; Purcell, Jeremiah M; Marshall, Alan G

2010-05-15

Dissolved organic matter (DOM) is a significant (>700 Pg) global C pool. Transport of terrestrial DOM to the inland waters and coastal zones represents the largest flux of reduced C from land to water (215 Tg yr(-1)) (Meybeck, M. Am. J. Sci. 1983, 282, 401-450). Oxidation of DOM by interdependent photochemical and biochemical processes largely controls the fate of DOM entering surface waters. Reactive oxygen species (ROS) have been hypothesized to play a significant role in the photooxidation of DOM, because they may oxidize the fraction of DOM that is inaccessible to direct photochemical degradation by sunlight. We followed the effects of photochemically produced singlet oxygen ((1)O(2)) on DOM by mass spectrometry with (18)O-labeled oxygen, to understand how (1)O(2)-mediated transformations of DOM may lead to altered DOM bioavailability. The photochemical oxygen uptake by DOM attributed to (1)O(2) increased with DOM concentration, yet it remained a minority contributor to photochemical oxygen uptake even at very high DOM concentrations. When DOM samples were exposed to (1)O(2)-generating conditions (Rose Bengal and visible light), increases were observed in DOM constituents with higher oxygen content and release of H(2)O(2) was detected. Differential effects of H(2)O(2) and (1)O(2)-treated DOM showed that (1)O(2)-treated DOM led to slower bacterial growth rates relative to unmodified DOM. Results of this study suggested that the net effect of the reactions between singlet oxygen and DOM may be production of partially oxidized substrates with correspondingly lower potential biological energy yield.

Water Quality Conditions in Upper Klamath and Agency Lakes, Oregon, 2006

USGS Publications Warehouse

Lindenberg, Mary K.; Hoilman, Gene; Wood, Tamara M.

2008-01-01

The U.S. Geological Survey Upper Klamath Lake water quality monitoring program gathered information from multiparameter continuous water quality monitors, physical water samples, dissolved oxygen production and consumption experiments, and meteorological stations during the June-October 2006 field season. The 2006 study area included Agency Lake and all of Upper Klamath Lake. Seasonal patterns in water quality were similar to those observed in 2005, the first year of the monitoring program, and were closely related to bloom dynamics of the cyanobacterium (blue-green alga) Aphanizomenon flos-aquae (AFA) in the two lakes. High dissolved oxygen and pH conditions in both lakes before the bloom declined in July, which coincided with seasonal high temperatures and resulted in seasonal lows in dissolved oxygen and decreased pH. Dissolved oxygen and pH in Upper Klamath and Agency Lakes increased again after the bloom recovered. Seasonal low dissolved oxygen and decreased pH coincided with seasonal highs in ammonia and orthophosphate concentrations. Seasonal maximum daily average temperatures were higher and minimum dissolved oxygen concentrations were lower in 2006 than in 2005. Conditions potentially harmful to fish were influenced by seasonal patterns in bloom dynamics and bathymetry. Potentially harmful low dissolved oxygen and high un-ionized ammonia concentrations occurred mostly at the deepest sites in the Upper Klamath Lake during late July, coincident with a bloom decline. Potentially harmful pH conditions occurred mostly at sites outside the deepest parts of the lake in July and September, coincident with a heavy bloom. Instances of possible gas bubble formation, inferred from dissolved oxygen data, were estimated to occur frequently in shallow areas of Upper Klamath and Agency Lakes simultaneously with potentially harmful pH conditions. Comparison of the data from monitors in nearshore areas and monitors near the surface of the water column in the open waters of Upper Klamath Lake revealed few differences in water quality dynamics. Median daily temperatures were higher in nearshore areas, and dissolved oxygen concentrations were periodically higher as well during periods of high AFA bloom. Differences between the two areas in water quality conditions potentially harmful to fish were not statistically significant (p < 0.05). Chlorophyll a concentrations varied temporally and spatially throughout Upper Klamath Lake. Chlorophyll a concentrations indicated an algal bloom in late June and early July that was followed by an algae bloom decline in late July and early August and a subsequent recovery in mid-August. Sites in the deepest part of the lake, where some of the highest chlorophyll a concentrations were observed, were the same sites where the lowest dissolved oxygen concentrations and the highest un-ionized ammonia concentrations were recorded during the bloom decline, indicating cell senescence. Total phosphorus concentrations limited the initial algal bloom in late June and early July. The rate of net dissolved oxygen production (that is, production in excess of community respiration) and consumption (due to community respiration) in the lake water column as measured in light and dark bottles, respectively, ranged from 2.79 to -2.14 milligrams of oxygen per liter per hour. Net production rate generally correlated positively with chlorophyll a concentration, except episodically at a few sites where high chlorophyll a concentrations resulted in self-shading that inhibited photosynthesis. The depth of photic zone was inversely correlated with chlorophyll a concentration. Calculations of a 24-hour change in dissolved oxygen concentration indicated that oxygen-consuming processes predominated at the deep trench sites and oxygen-producing processes predominated at the shallow sites. In addition, calculations of the 24-hour change in dissolved oxygen indicate that oxygen-consuming processes in the water column di

Data-Logging--A Plug-and-Play Oxygen Probe?

ERIC Educational Resources Information Center

Warne, Peter

1997-01-01

Presents an experiment on collecting data while measuring the dissolved-oxygen levels in Thames River tap water straight from the water mains and dissolved-oxygen levels in rainwater containing Hornwort water weed over 24 hours. (Author/ASK)

Assessment of water quality and factors affecting dissolved oxygen in the Sangamon River, Decatur to Riverton, Illinois, summer 1982

USGS Publications Warehouse

Schmidt, A.R.; Stamer, J.K.

1987-01-01

Water quality and processes that affect the dissolved-oxygen concentration in a 45.9 mile reach of the Sangamon River from Decatur to Riverton, Illinois, were determined from data collected during low-flow periods in the summer of 1982. Relations among dissolved oxygen, water discharge, biochemical oxygen demand, ammonia and nitrite plus nitrate concentrations, and photosynthetic-oxygen production were simulated using a one-dimensional, steady-state computer model. Average dissolved oxygen concentrations ranged from 8.0 milligrams per liter at the upstream end of the study reach at Decatur to 5.2 milligrams per liter 12.2 miles downstream. Ammonia concentrations ranged from 45 milligrams per liter at the mouth of Stevens Creek (2.6 miles downstream from Decatur) to 0.03 milligram per liter at the downstream end of the study reach. Un-ionized ammonia concentrations exceeded the maximum concentration specified in the State water quality standard (0.04 milligram per liter) throughout most of the study reach. Model simulations indicated that oxidation of ammonia to form nitrite plus nitrate was the most significant process leading to low dissolved oxygen concentrations in the river. (USGS)

Using cerium anomaly as an indicator of redox reactions in constructed wetland

NASA Astrophysics Data System (ADS)

Liang, R.

2013-12-01

The study area, Chiayi County located in southern Taiwan, has highly developed livestock. The surface water has very low dissolved oxygen and high NH4. Under the situation, constructed wetland becomes the most effective and economic choice to treat the wastewater in the natural waterways. Hebao Island free surface constructed wetland started to operate in late 2006. It covers an area of 0.28 km2 and is subdivided into 3 major cells, which are sedimentation cell, 1st aeration cell with rooted plants and 2nd aeration cell with float plants. The water depth of cells ranges from 0.6 m to 1.2 m. The total hydraulic retention time is about a half day. In this study, the water samples were sequentially collected along the flow path. The results of hydrochemical analysis show that the untreated inflow water can be characterized with enriched NH4 (11 ppm), sulfate (6 ppm) and arsenic (50 ppb). The removal efficiency of NH4 in the first two cells is <15%. However, the efficiency dramatically increases in the 2nd aeration cell, which is over 90%. Simultaneously, almost all of the hydrochemical properties, including EC, Ca, Mg, As Fe, Mn and other heavy metals, decrease while dissolve oxygen increases close to saturated level and aluminum is almost doubled in the exit of constructed wetland. However, the removal of sulfate and phosphate is very weak. It is worth to note that arsenic is still higher than the permissible limits recommended by WHO (10 ppb). The wetland operation should be tuned to take more arsenic away in the future. As demonstrated in the above, oxidation reaction is the most dominant mechanism to remove pollutants from the wastewater; therefore, dissolved oxygen is traditionally considered as an important indicator to evaluate the operation efficiency of wetland. However, it would need longer time to achieve equilibrium state of redox reaction involving dissolved oxygen due to the slower reaction rate. For example, the input water in this study has fairly high dissolved oxygen (5 ppm) but the NH4 content is still high, which indicates a non-equilibrium condition. In this study, the cerium anomaly is alternatively utilized to evaluate the water redox state. The results demonstrate that the input water has the negative cerium anomaly of -0.16. Along the flow path, the cerium negative anomaly does not change in the first two cells and dramatically becomes -0.23 in cell 3. The trend of cerium anomaly is more close to the removal efficiency of NH4 rather than dissolve oxygen. Accordingly, cerium anomaly could become a better indicator of removal efficiency of constructed wetland.

Sedimentary pigments and nature of organic matter within the oxygen minimum zone (OMZ) of the Eastern Arabian Sea (Indian margin)

NASA Astrophysics Data System (ADS)

Rasiq, K. T.; Kurian, S.; Karapurkar, S. G.; Naqvi, S. W. A.

2016-07-01

Sedimentary pigments, carbon and nitrogen content and their stable isotopes were studied in three short cores collected from the oxygen minimum zone (OMZ) of the Eastern Arabian Sea (EAS). Nine pigments including chlorophyll a and their degradation products were quantified using High Performance Liquid Chromatography (HPLC). Astaxanthin followed by canthaxanthin and zeaxanthin were the major carotenoids detected in these cores. The total pigment concentration was high in the core collected from 500 m water depth (6.5 μgg-1) followed by 800 m (1.7 μgg-1) and 1100 m (1.1 μgg-1) depths respectively. The organic carbon did not have considerable control on sedimentary pigments preservation. Pigment degradation was comparatively high in the core collected from the 800 m site which depended not only the bottom dissolved oxygen levels, but also on the faunal activity. As reported earlier, the bottom water dissolved oxygen and presence of fauna have good control on the organic carbon accumulation and preservation at Indian margin OMZ sediments. The C/N ratios and δ13C values for all the cores conclude the marine origin of organic matter and δ15N profiles revealed signature of upwelling associated denitrification within the water column.

Variability of dissolved oxygen over the last millennium and the 21st century in CESM

NASA Astrophysics Data System (ADS)

Hameau, Angélique; Joos, Fortunat; Mignot, Juliette; Keller, Kathrin

2017-04-01

The earth system models simulate a depletion of the oxygen content in the ocean under global warming conditions (Cocco et al. 2012, Frölicher et al. 2009). The response to external forcing and mechanism underlying this evolution are not completely understood. Physical and biogeochemical processes are involved and tangled up to each other leading to a decrease of the global mean concentration of O2 in the ocean with the increase of the ocean temperature. This result is supported by experimental and observational studies in Atlantic and Pacific oceans (Stramma et al. 2008, Brandt et al. 2010). Here, we study the evolution of dissolved oxygen in a climate simulation of the Community Earth System Model (CESM) covering the last millennium and the 21st century. This long period allows us to identify the natural variability of the climate in this system, and therefore analyse the time of emergence (ToE) of the anthropogenic signal under the RCP8.5 scenario. Based on Keller et al. 2014, the time of emergence is defined as the point in time when the trend signal reaches twice the standard deviation of the signal during the preindustrial period (1000 years). The ToE of oxygen and of temperature present an offset. We show that the anthropogenic emissions are seen in a first hand by the oxygen and only then by the temperature. We also look at the OMZ response. The oxygen minimum zones result from a combination of weak ventilation and sustained respiration by the microorgamisms. With a global decrease of the oceanic oxygen content, the OMZ may therefore expand impacting the environment of marine species. But this statement is questioned by Deutsch et al 2014, who relates the variations of Pacific OMZ to the variations of the tropical Walker circulation. The CESM climate model predicts an expansion of the oxygen low zones and the emergence of new ones over the last century. Magnitude and timescales of these responses will be discussed and compared to natural variability.

[Influence of the Concentration of Dissolved Oxygen on Embryonic Development of the Common Toad (Bufo bufo)].

PubMed

Dmitrieva, E V

2015-01-01

Several series of experiments investigating the influence of dissolved oxygen concentrations on the growth rates and mortality in the embryogenesis of the common toad Bufo bufo were carried out. The experiments showed that, when the eggs develop singly, the lack of oxygen does not lead to an increase in mortality by the time of hatching and results only in a change in the dynamics of mortality: mortality occurs at an earlier stage of development than in the conditions of normal access to oxygen. Taking into account the combined effect of the density of eggs and the dissolved oxygen concentration, we increase the accuracy of analysis of the experimental results and improve the interpretation of the results. In the conditions of different initial density of eggs, the impact of the concentration of dissolved oxygen on mortality and rates of development of the common toad embryos is manifested in different ways. At high density, only a small percentage of embryos survives by the time of hatching, and the embryos are significantly behind in their development compared with the individuals that developed in normal oxygen conditions. The lack of oxygen dissolved in the water slows down the development of embryos of the common toad.

Global Visualization in Water using AnodizedAluminum PressureSensitive Paint and Dissolved Oxygen as Tracer

NASA Astrophysics Data System (ADS)

Ozaki, Tatsuya; Ishikawa, Hitoshi; Sakaue, Hirotaka

2009-11-01

We have developed anodized-aluminum pressuresensitive paint (AA-PSP) for flow visualization in water using dissolved oxygen as a tracer. Developed AA-PSP is characterized using water calibration setup by controlling a dissolved oxygen concentration. It is shown that the developed AA-PSP gives 4.0 percent change in luminescence per 1 mg/l of oxygen concentration. This AA-PSP is applied to visualize flows in a water tunnel. Oxygen concentrations of the water tunnel and the dissolved oxygen are 9.5 mg/l and 20 mg/l, respectively. We can capture horseshoe vortices over the base of 10 mm cylinder by using this technique at Reynolds number of 1000 and a water speed of 100 mm/s, respectively. Unlike conventional tracers such as ink, milk, and fluorescent dyes, this visualization technique gives flow information on the AA-PSP coated surface without integrating flows between the AA-PSP and an optical detector. Because of using dissolved oxygen as a tracer, it holds the material properties of testing water except for the amount of oxygen. The tracer does not interfere with optical measurements and it does not contaminate the testing water. A conventional visualization technique using milk as a tracer is also employed for comparison.

Water Quality and optical properties of Crater Lake, Oregon

USGS Publications Warehouse

Larson, Gary L.; Hoffman, Robert L.; McIntire, C.D.; Buktenica, M.W.; Girdner, Scott

2007-01-01

We examine observations of key limnological properties (primarily temperature, salinity, and dissolved oxygen), measured over a 14-year period in Crater Lake, Oregon, and discuss variability in the hypolimnion on time scales of days to a decade. During some years (e.g., 1994a??1995), higher-than-average wintertime deep convection and ventilation led to the removal of significant amounts of heat and salt from the hypolimnion, while dissolved oxygen concentrations increase. In other years, such as the winter of 1996a??1997, heat and salt concentrations increase throughout the year and dissolved oxygen levels drop, indicating conditions were dominated by the background geothermal inputs and dissolved oxygen consumption by bacteria (i.e., minimal deep convection). Over the entire 14 year period, no statistically significant trend was observed in the annual hypolimnetic heat and salt content. Measurements from several thermistors moored in the hypolimnion provide new insight into the time and space scales of the deep convection events. For some events, cool water intrusions are observed sequentially, from shallower depths to deeper depths, suggesting vertical mixing or advection from above. For other events, the cooling is observed first at the deepest sensors, suggesting a thin, cold water pulse that flows along the bottom and mixes more slowly upwards into the basin. In both cases, the source waters must originate from the epilimnion. Conditions during a strong ventilation year (1994a??1995) and a weak ventilation year (1996a??1997) were compared. The results suggest the major difference between these 2 years was the evolution of the stratification in the epilimnion during the first few weeks of reverse stratification such that thermobaric instabilities were easier to form during 1995 thana?#1997. Thus, the details of surface cooling and wind-driven mixing during the early stages ofa?#reverse stratification may determine the neta?#amount of ventilation possible during a particular year.

A one-dimensional, steady-state, dissolved-oxygen model and waste-load assimilation study for Cedar Creek, Dekalb and Allen counties, Indiana

USGS Publications Warehouse

Wilber, William G.; Peters, J.G.; Ayers, M.A.; Crawford, Charles G.

1979-01-01

A digital model calibrated to conditions in Cedar Creek was used to develop alternatives for future waste loadings that would be compatible with Indiana stream water-quality standards defined for two critical hydrologic conditions, summer and winter low flows. The model indicates that the dissolved-oxygen concentration of the Auburn wastewater effluent and nitrification are the most significant factors affecting the dissolved-oxygen concentration in Cedar Creek during summer low flows. The observed dissolved-oxygen concentration of the Auburn wastewater effluent was low and averaged 30 percent of saturation. Projected nitrogenous biochemical-oxygen demand loads, from the Indiana State Board of Health, for the Auburn and Waterloo wastewater-treatment facilities will result in violations of the current instream dissolved-oxygen standard (5 mg/l), even with an effluent dissolved-oxygen concentration of 80 percent saturation. Natural streamflow for Cedar Creek upstream from the confluence of Willow and Little Cedar Creeks is small compared with the waste discharge, so benefits of dilution for Waterloo and Auburn are minimal. The model also indicates that, during winter low flows, ammonia toxicity, rather than dissolved oxygen, is the limiting water-quality criterion in the reach of Cedar Creek downstream from the wastewater-treatment facility at Auburn and the confluence of Garrett ditch. Ammonia-nitrogen concentrations predicted for 1978 through 2000 downstream from the Waterloo wastewater-treatment facility do not exceed Indiana water-quality standards for streams. Calculations of the stream 's assimilative capacity indicate that future waste discharge in the Cedar Creek basin will be limited to the reaches between the Auburn wastewater-treatment facility and County Road 68. (Kosco-USGS)

Fate of leaf litter deposits and impacts on oxygen availability in bank filtration column studies.

PubMed

Bayarsaikhan, Uranchimeg; Filter, Josefine; Gernert, Ulrich; Jekel, Martin; Ruhl, Aki Sebastian

2018-07-01

Degradation of particulate organic carbon (POC) such as leaf litter might deplete dissolved oxygen within the upper layers of bank filtration, an efficient and robust barrier for pathogens and for various organic micro-pollutants (OMP) in water supply systems worldwide. The degradation of OMP during bank filtration depends on the redox conditions. The present study aimed at identifying the impacts and fates of different local leaves on the oxygen consumption and the possible biological degradation of indicator OMP. Oxygen concentrations initially decreased within the columns from around 8 mg/L in the influent to low concentrations indicating extensive consumption within a short travel distance. Still a substantial oxygen consumption was observed after 250 days. OMP concentrations were not significantly affected by the microbial processes. A layer of calcium carbonate crystallites was observed on the POC layer. Some leaf fragments appeared to be persistant towards degradation and the carbon content relative to nitrogen and sulfur contents decreased within 250 days. The results demonstrate that trees at bank filtration sites might have a strong long-term impact on the subsurface redox conditions. Copyright © 2018 Elsevier Inc. All rights reserved.

Survival, development, and growth of fall Chinook salmon embryos, alevin, and fry exposed to variable thermal and dissolved oxygen regimes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Geist, David R.; Abernethy, Cary S.; Hand, Kristine D.

2006-11-15

Some fall Chinook salmon (Oncorhynchus tshawytscha) initiate spawning in the Snake River downstream of Hells Canyon Dam at temperatures that exceed 13?C and at intergravel dissolved oxygen concentrations that are less than 8 mg O2/L. Although water temperature declines and dissolved oxygen increases soon after spawning, these temperature and dissolved oxygen levels do not meet the water quality standards established by the states of Oregon and Idaho for salmonid spawning. Our objective was to determine if temperatures from 13 to 17 C and dissolved oxygen levels from 4 to greater than 8 mg O2/L during the first 40 days ofmore » incubation followed by declining temperature and rising dissolved oxygen affected survival, development, and growth of Snake River fall Chinook salmon embryos, alevins, and fry. During the first 40 days of incubation, temperatures were adjusted downward approximately 0.2 C/day and oxygen was increased in increments of 2 mg O2/L to mimic the thermal and oxygen regime of the Snake River where these fish spawn. At 40 days post-fertilization, embryos were moved to a common exposure regime that followed the thermal and dissolved oxygen profile of the Snake River through emergence. Mortality of fall Chinook salmon embryos increased markedly at initial incubation temperatures equal to or greater than 17?C, and a rapid decline in survival occurred between 16.5 C and 17 C, with no significant difference in survival at temperatures less than or equal to 16.5 C. Initial dissolved oxygen levels as low as 4 mg O2/L over a range of initial temperatures from 15 to 16.5 C did not affect embryo survival to emergence. There were no significant differences across the range of initial temperature exposures for alevin and fry size at hatch and emergence. The number of days from fertilization to eyed egg, hatch, and emergence was highly related to temperature and dissolved oxygen; it took from 6 to 10 days longer to reach hatch at 4 mg O2/L than at saturation and up to 24 days longer to reach emergence. In contrast, within each dissolved oxygen treatment, it took about 20 days longer to reach hatch at 13 C than at 16.5 C (no data for 17 C) and up to 41 days longer to reach emergence. Overall, this study indicates that exposure to water temperatures up to 16.5 C will not have deleterious impacts on survival or growth from egg to emergence if temperatures decline at a rate of greater than or equal to 0.2 C/day following spawning. Although fall Chinook salmon survived low initial dissolved oxygen levels, the delay in emergence could have significant long-term effects on their survival. Thus, an exemption to the state water quality standards for temperature but not oxygen may be warranted in the Snake River where fall Chinook salmon spawn.« less

Photolytically driven generation of dissolved oxygen and increased oxyhemoglobin in whole blood.

PubMed

Monzyk, Bruce F; Burckle, Eric C; Carleton, Linda M; Busch, James; Dasse, Kurt A; Martin, Peter M; Gilbert, Richard J

2006-01-01

The severely debilitating nature of chronic lung disease has long provided the impetus for the development of technologies to supplement the respiratory capacity of the human lung. Although conventional artificial lung technologies function by delivering pressurized oxygen to the blood through a system of hollow fibers or tubes, our approach uses photolytic energy to generate dissolved oxygen (DO) from the water already present in blood, thus eliminating the need for gas delivery. We have previously demonstrated that it is feasible to generate dissolved oxygen from water based on UVA illumination of a highly absorbent TiO2 thin film. In the current study, we extend this work by using photolytic energy to generate DO from whole blood, thus resulting in an increase of oxyhemoglobin as a function of back side TiO2 surface film illumination. Initial experiments, performed with Locke's Ringer solution, demonstrated effective film thickness and material selection for the conductive layer. The application of a small bias voltage was used to conduct photogenerated electrons from the aqueous phase to minimize electron recombination with the DO.Mixed arterial-venous bovine blood was flowed in a recirculating loop over TiO2 nanocrystalline films illuminated on the side opposite the blood (or "back side") to eliminate the possibility of any direct exposure of blood to light. After light exposure of the TiO2 film, the fraction of oxyhemoglobin in the blood rapidly increased to near saturation and remained stable throughout the trial period. Last, we evaluated potential biofouling of the DO generating surface by scanning electron microscopy, after photolytically energized DO generation in whole blood, and observed no white or red blood cell surface deposition, nor the accumulation of any other material at this magnification. We conclude that it is feasible to photolytically oxygenate the hemoglobin contained in whole blood with oxygen derived from the blood's own water content without involving a gaseous phase.

Oxygen removal during pathogen inactivation with riboflavin and UV light preserves protein function in plasma for transfusion.

PubMed

Feys, H B; Van Aelst, B; Devreese, K; Devloo, R; Coene, J; Vandekerckhove, P; Compernolle, V

2014-05-01

Photochemical pathogen inactivation technologies (PCT) for individual transfusion products act by inhibition of replication through irreversibly damaging nucleic acids. Concern on the collateral impact of PCT on the blood component's integrity has caused reluctance to introduce this technology in routine practice. This work aims to uncover the mechanism of damage to plasma constituents by riboflavin pathogen reduction technology (RF-PRT). Activity and antigen of plasma components were determined following RF-PRT in the presence or absence of dissolved molecular oxygen. Employing ADAMTS13 as a sentinel molecule in plasma, our data show that its activity and antigen are reduced by 23 ± 8% and 29 ± 9% (n = 24), respectively, which corroborates with a mean decrease of 25% observed for other coagulation factors. Western blotting of ADAMTS13 shows decreased molecular integrity, with no obvious indication of additional proteolysis nor is riboflavin able to directly inhibit the enzyme. However, physical removal of dissolved oxygen prior to RF-PRT protects ADAMTS13 as well as FVIII and fibrinogen from damage, indicating a direct role for reactive oxygen species. Redox dye measurements indicate that superoxide anions are specifically generated during RF-PRT. Protein carbonyl content as a marker of disseminated irreversible biomolecular damage was significantly increased (3·1 ± 0·8 vs. 1·6 ± 0·5 nmol/mg protein) following RF-PRT, but not in the absence of dissolved molecular oxygen (1·8 ± 0·4 nmol/mg). RF-PRT of single plasma units generates reactive oxygen species that adversely affect biomolecular integrity of relevant plasma constituents, a side-effect, which can be bypassed by applying hypoxic conditions during the pathogen inactivation process. © 2013 International Society of Blood Transfusion.

Water quality and discharge of streams in the Lehigh River Basin, Pennsylvania

USGS Publications Warehouse

McCarren, Edward F.; Keighton, Walter B.

1969-01-01

The Lehigh River, 100 miles long, is the second largest tributary to the Delaware River. It drains 1,364 square miles in four physiographic provinces. The Lehigh River basin includes mountainous and forested areas, broad agricultural valleys and areas of urban and industrial development. In the headwaters the water is of good quality and has a low concentration of solutes. Downstream, some tributaries receive coal-mine drainage and become acidic; others drain areas underlain by limestone and acquire alkaline characteristics. The alkaline streams neutralize and dilute the acid mine water where they mix. The dissolved-oxygen content of river water, which is high in the upper reaches of the stream, is reduced in the lower reaches because of lower turbulence, higher temperature, and the respiration of organisms. The Lehigh is used for public supply, recreation, waterpower, irrigation, and mining and other industrial purposes. Because the river is shallow in its upper reaches, most of the water comes in contact with the atmosphere as it churns over rocks and around islets and large boulders. Aeration of the water is rapid. When water that was low in dissolved-oxygen concentration was released from the lower strata of the Francis E. Walter Reservoir in June 1966, it quickly became aerated in the Lehigh River, and for 40 miles downstream from the dam the water was nearly saturated with oxygen. Most of the river water requires only moderate treatment for industrial use and public distribution throughout the Lehigh River valley. At times, however, some segments of the main river and its tributaries transport industrial wastes and acid coal-mine drainage. Usually the relatively high concentrations of solutes in water and the ensuing damage caused to quality by such waste discharges are more extensive and prolonged during droughts and other periods of low streamflow. For many years the Lehigh River flow has been continuously measured and its water chemically analyzed. Since May 1966 an instrument installed by the U.S. Geological Survey at Easton, Pa., has continuously recorded such water-quality parameters as specific conductance, temperature, and dissolved oxygen content.

The sediment and hydrographic characteristics of three horseshoe crab nursery beaches in hong kong

NASA Astrophysics Data System (ADS)

Chiu, Helen M. C.; Morton, Brian

2003-04-01

Horseshoe crab juveniles have been recorded from sand and sandy-mud nursery beaches at Pak Nai (western New Territories), San Tau and Shui Hau (Lantau Island), Hong Kong. In order to provide a better understanding of these beaches and to identify those plausible factors which have made them preferred by spawning horseshoe crabs, environmental parameters, including temperature, salinity, pH and dissolved oxygen content of the water, and particle size distribution and organic matter content of the sediments at the three sites, were determined and compared. The hydrographic, and sediment data obtained for the three study sites have revealed some common environmental features. The three nursery beaches are relatively remote, and far (in Hong Kong terms) from urbanized and densely populated areas. The beaches are generally well sheltered from strong wave action and inundated regularly by estuarine waters. Horseshoe crab adults tend to select these beaches for spawning as their protected features ensures the laid eggs are less likely to be washed out of the sand, and hatched juveniles can feed on the meiofauna and grow. Sediments of the three beaches largely comprise medium-sized sand particles and are moderately sorted, suggesting medium porosity and good water permeability. Such a sand type, with the generally high oxygen levels in incursing waters, may help create a well-oxygenated micro-environment for the normal development of horseshoe crab eggs, larvae and juveniles. Lantau Island beaches at San Tau and Shui Hau are relatively free from organic pollution, as reflected in generally high dissolved oxygen level, and low BOD5 and ammonia nitrogen values. Pak Nai is, however, more polluted.

Dissolved Oxygen Levels in Lake Chabot

NASA Astrophysics Data System (ADS)

Sharma, D.; Pica, R.

2014-12-01

Dissolved oxygen levels are crucial in every aquatic ecosystem; it allows for the fish to breathe and it is the best indicator of water quality. Lake Chabot is the main backup water source for Castro Valley, making it crucial that the lake stays in good health. Last year, research determined that the water in Lake Chabot was of good quality and not eutrophic. This year, an experiment was conducted using Lake Chabot's dissolved oxygen levels to ensure the quality of the water and to support the findings of the previous team. After testing three specifically chosen sites at the lake using a dissolved oxygen meter, results showed that the oxygen levels in the lake were within the healthy range. It was then determined that Lake Chabot is a suitable backup water source and it continues to remain a healthy habitat.

An evaluation of a micro programmable logic controller for oxygen monitoring and control in tanks of a recirculating aquaculture system

USDA-ARS?s Scientific Manuscript database

Control of dissolved gases, especially oxygen is an essential component of recirculating aquaculture systems. The use of pure oxygen in a recirculating aquaculture system creates supersaturated concentrations of dissolved oxygen and can reduce fish production costs by supporting greater fish and fee...

Dissolved oxygen in the Tualatin River, Oregon, during winter flow conditions, 1991 and 1992

USGS Publications Warehouse

Kelly, V.J.

1996-01-01

Throughout the winter period, November through April, wastewater treatment plants in the Tualatin River Basin discharge from 10,000 to 15,000 pounds per day of biochemical oxygen demand to the river. These loads often increase substantially during storms when streamflow is high. During the early winter season, when streamflow is frequently less than the average winter flow, the treatment plants discharge about 2,000 pounds per day of ammonia. This study focused on the capacity of the Tualatin River to assimilat oxygen-demanding loads under winter streamflow conditions during the 1992 water year, with an emphasis on peak-flow conditions in the river, and winter-base-flow conditions during November 1992. Concentrations of dissolved oxygen throughout the main stem of the river during the winter remained generally high relative to the State standard for Oregon of 6 milligrams per liter. The most important factors controlling oxygen consumption during winter-low-flow conditions were carbonaceous biochemical oxygen demand and input of oxygen-depleted waters from tributaries. During peak-flow conditions, reduced travel time and increased dilution associated with the increased streamflow minimized the effect of increased oxygen-demanding loads. During the base-flow period in November 1992, concentrations of dissolved oxygen were consistently below 6 milligrams per liter. A hydrodynamic water-quality model was used to identify the processes depleting dissolved oxygen, including sediment oxygen demand, nitrification, and carbonaceous biochemical oxygen demand. Sediment oxygen demand was the most significant factor; nitrification was also important. Hypothetical scenarios were posed to evaluate the effect of different wastewater treatment plant loads during winter-base-flow conditions. Streamflow and temperature were significant factors governing concentrations of dissolved oxygen in the main-stem river.

Streamflow and water-quality conditions, Wilsons Creek and James River, Springfield area, Missouri

USGS Publications Warehouse

Berkas, Wayne R.

1982-01-01

A network of water-quality-monitoring stations was established upstream and downstream from the Southwest Wastewater-Treatment Plant on Wilsons Creek to monitor the effects of sewage effluent on water quality. Data indicate that 82 percent of the time the flow in Wilsons Creek upstream from the wastewater-treatment plant is less than the effluent discharged from the plant. On October 15, 1977, an advanced wastewater-treatment facility was put into operation. Of the four water-quality indicators measured at the monitoring stations (specific conductance, dissolved oxygen, pH, and water temperature), only dissolved oxygen showed improvement downstream from the plant. During urban runoff, the specific conductance momentarily increased and dissolved-oxygen concentration momentarily decreased in Wilsons Creek upstream from the plant. Urban runoff was found to have no long-term effects on specific conductance and dissolved oxygen downstream from the plant before or after the addition of the advanced wastewater-treatment facility. Data collected monthly from the James River showed that the dissolved-oxygen concentrations and the total nitrite plus nitrate nitrogen concentrations increased, whereas the dissolved-manganese concentrations decreased after the advanced wastewater-treatment facility became operational.

Harvesting energy from the marine sediment--water interface.

PubMed

Reimers, C E; Tender, L M; Fertig, S; Wang, W

2001-01-01

Pairs of platinum mesh or graphite fiber-based electrodes, one embedded in marine sediment (anode), the other in proximal seawater (cathode), have been used to harvest low-level power from natural, microbe established, voltage gradients at marine sediment-seawater interfaces in laboratory aquaria. The sustained power harvested thus far has been on the order of 0.01 W/m2 of electrode geometric area but is dependent on electrode design, sediment composition, and temperature. It is proposed that the sediment/anode-seawater/cathode configuration constitutes a microbial fuel cell in which power results from the net oxidation of sediment organic matter by dissolved seawater oxygen. Considering typical sediment organic carbon contents, typical fluxes of additional reduced carbon by sedimentation to sea floors < 1,000 m deep, and the proven viability of dissolved seawater oxygen as an oxidant for power generation by seawater batteries, it is calculated that optimized power supplies based on the phenomenon demonstrated here could power oceanographic instruments deployed for routine long-term monitoring operations in the coastal ocean.

Natural realgar and amorphous AsS oxidation kinetics

NASA Astrophysics Data System (ADS)

Lengke, Maggy F.; Tempel, Regina N.

2003-03-01

The oxidation rates of natural realgar and amorphous synthetic AsS by dissolved oxygen were evaluated using mixed flow reactors at pH 7.2 to 8.8 and dissolved oxygen contents of 5.9 to 16.5 ppm over a temperature range of 25 to 40°C. The ratios of As/S are stoichiometric for all amorphous AsS oxidation experiments except for two experiments conducted at pH ˜8.8. In these experiments, stoichiometric ratios of As/S were only observed in the early stages of AsS (am) oxidation whereas lower As/S ratios were observed during steady state. For realgar oxidation experiments, the As/S ratio is less than the stoichiometric ratio of realgar, ranging between 0.61 and 0.71. This nonstoichiometric release of As and S to solution indicates that realgar oxidation is more selective for S after the rates of oxidation become constant. All measured oxidation rates at 25°C can be described within experimental uncertainties as follows: Table 1

Remote Sensing of Dissolved Oxygen and Nitrogen in Water Using Raman Spectroscopy

NASA Technical Reports Server (NTRS)

Ganoe, Rene; DeYoung, Russell J.

2013-01-01

The health of an estuarine ecosystem is largely driven by the abundance of dissolved oxygen and nitrogen available for maintenance of plant and animal life. An investigation was conducted to quantify the concentration of dissolved molecular oxygen and nitrogen in water by means of Raman spectroscopy. This technique is proposed for the remote sensing of dissolved oxygen in the Chesapeake Bay, which will be utilized by aircraft in order to survey large areas in real-time. A proof of principle system has been developed and the specifications are being honed to maximize efficiency for the final application. The theoretical criteria of the research, components of the experimental system, and key findings are presented in this report

PHYSICAL AND BIOLOGICAL CONTROLS ON DISSOLVED OXYGEN DYNAMICS IN PENSACOLA BAY, FL

EPA Science Inventory

Nutrient enrichment of estuaries and coastal waters can contribute to hypoxia (low dissolved oxygen) by increasing primary production and biological oxygen demand. Other factors, however, contribute to hypoxia and affect the susceptibility of coastal waters to hypoxia. Hypoxia fo...

Water-quality assessment of White River between Lake Sequoyah and Beaver Reservoir, Washington County, Arkansas

USGS Publications Warehouse

Terry, J.E.; Morris, E.E.; Bryant, C.T.

1982-01-01

The Arkansas Department of Pollution Control and Ecology and U.S. Geological Survey conducted a water quality assessment be made of the White River and, that a steady-state digital model be calibrated and used as a tool for simulating changes in nutrient loading. The city of Fayetteville 's wastewater-treatment plant is the only point-source discharger of waste effluent to the river. Data collected during synoptic surveys downstream from the wastewater-treatment plan indicate that temperature, dissolved oxygen, dissolved solids, un-ionized ammonia, total phosphorus, and floating solids and depositable materials did not meet Arkansas stream standards. Nutrient loadings below the treatment plant result in dissolved oxygen concentrations as low as 0.0 milligrams per liter. Biological surveys found low macroinvertebrate organism diversity and numerous dead fish. Computed dissolved oxygen deficits indicate that benthic demands are the most significant oxygen sinks in the river downstream from the wastewater-treatment plant. Benthic oxygen demands range from 2.8 to 11.0 grams per meter squared per day. Model projections indicate that for 7-day, 10-year low-flow conditions and water temperature of 29 degrees Celsius, daily average dissolved oxygen concentrations of 6.0 milligrams per liter can be maintained downstream from the wastewater-treatment plant if effluent concentrations of ultimate carbonaceous biochemical oxygen demand and ammonia nitrogen are 7.5 (5.0 5-day demand) and 2 milligrams per liter respectively. Model sensitivity analysis indicate that dissolved oxygen concentrations were most sensitive to changes in stream temperature. (USGS)

Monitoring of impact of anthropogenic inputs on water quality of mangrove ecosystem of Uran, Navi Mumbai, west coast of India.

PubMed

Pawar, Prabhakar R

2013-10-15

Surface water samples were collected from substations along Sheva creek and Dharamtar creek mangrove ecosystems of Uran (Raigad), Navi Mumbai, west coast of India. Water samples were collected fortnightly from April 2009 to March 2011 during spring low and high tides and were analyzed for pH, Temperature, Turbidity, Total solids (TS), Total dissolved solids (TDS), Total suspended solids (TSS), Dissolved oxygen (DO), Biochemical oxygen demand (BOD), Carbon dioxide (CO2), Chemical oxygen demand (COD), Salinity, Orthophosphate (O-PO4), Nitrite-nitrogen (NO2-N), Nitrate-nitrogen (NO3-N), and Silicates. Variables like pH, turbidity, TDS, salinity, DO, and BOD show seasonal variations. Higher content of O-PO4, NO3-N, and silicates is recorded due to discharge of domestic wastes and sewage, effluents from industries, oil tanking depots and also from maritime activities of Jawaharlal Nehru Port Trust (JNPT), hectic activities of Container Freight Stations (CFS), and other port wastes. This study reveals that water quality from mangrove ecosystems of Uran is deteriorating due to industrial pollution and that mangrove from Uran is facing the threat due to anthropogenic stress. Copyright © 2013 Elsevier Ltd. All rights reserved.

The importance of dissolved free oxygen during formation of sandstone-type uranium deposits

USGS Publications Warehouse

Granger, Harry Clifford; Warren, C.G.

1979-01-01

One factor which distinguishes t, he genesis of roll-type uranium deposits from the Uravan Mineral Belt and other sandstone-type uranium deposits may be the presence and concentration of dissolved free oxygen in the ore-forming. solutions. Although dissolved oxygen is a necessary prerequisite for the formation of roll-type deposits, it is proposed that a lack of dissolved oxygen is a prerequisite for the Uravan deposits. Solutions that formed both types of deposits probably had a supergene origin and originated as meteoric water in approximate equilibrium with atmospheric oxygen. Roll-type deposits were formed where the Eh dropped abruptly following consumption of the oxygen by iron sulfide minerals and creation of kinetically active sulfur species that could reduce uranium. The solutions that formed the Uravan deposits, on the other hand, probably first equilibrated with sulfide-free ferrous-ferric detrital minerals and fossil organic matter in the host rock. That is, the uraniferous solutions lost their oxygen without lowering their Eh enough to precipitate uranium. Without oxygen, they then. became incapable of oxidizing iron sulfide minerals. Subsequent localization and formation of ore bodies from these oxygen-depleted solutions, therefore, was not necessarily dependent on large reducing capacities.

Modelling in-stream temperature and dissolved oxygen at sub-daily time steps: an application to the River Kennet, UK.

PubMed

Williams, Richard J; Boorman, David B

2012-04-15

The River Kennet in southern England shows a clear diurnal signal in both water temperature and dissolved oxygen concentrations through the summer months. The water quality model QUESTOR was applied in a stepwise manner (adding modelled processes or additional data) to simulate the flow, water temperature and dissolved oxygen concentrations along a 14 km reach. The aim of the stepwise model building was to find the simplest process-based model which simulated the observed behaviour accurately. The upstream boundary used was a diurnal signal of hourly measurements of water temperature and dissolved oxygen. In the initial simulations, the amplitude of the signal quickly reduced to zero as it was routed through the model; a behaviour not seen in the observed data. In order to keep the correct timing and amplitude of water temperature a heating term had to be introduced into the model. For dissolved oxygen, primary production from macrophytes was introduced to better simulate the oxygen pattern. Following the modifications an excellent simulation of both water temperature and dissolved oxygen was possible at an hourly resolution. It is interesting to note that it was not necessary to include nutrient limitation to the primary production model. The resulting model is not sufficiently proven to support river management but suggests that the approach has some validity and merits further development. Crown Copyright © 2012. Published by Elsevier B.V. All rights reserved.

DIEL OXYGEN-INDUCED MOVEMENT OF FISH ASSEMBLAGES IN A GREAT LAKES COASTAL WETLAND

EPA Science Inventory

To determine the importance of dissolved oxygen conditions in influencing daily ovement patterns of fishes in Great Lakes coastal wetlands, we sampled migrating fish assemblages from habitats with varying diurnal dissolved oxygen patterns in a Lake Superior coastal wetland during...

Effects of climate events driven hydrodynamics on dissolved oxygen in a subtropical deep reservoir in Taiwan.

PubMed

Fan, Cheng-Wei; Kao, Shuh-Ji

2008-04-15

The seasonal concentrations of dissolved oxygen in a subtropical deep reservoir were studied over a period of one year. The study site was the Feitsui Reservoir in Taiwan. It is a dam-constructed reservoir with a surface area of 10.24 km(2) and a mean depth of 39.6 m, with a maximum depth of 113.5 m near the dam. It was found that certain weather and climate events, such as typhoons in summer and autumn, as well as cold fronts in winter, can deliver oxygen-rich water, and consequently have strong impacts on the dissolved oxygen level. The typhoon turbidity currents and winter density currents played important roles in supplying oxygen to the middle and bottom water, respectively. The whole process can be understood by the hydrodynamics driven by weather and climate events. This work provides the primary results of dissolved oxygen in a subtropical deep reservoir, and the knowledge is useful in understanding water quality in subtropical regions.

In situ measurements of dissolved oxygen, pH and redox potential of biocathode microenvironments using microelectrodes.

PubMed

Wang, Zejie; Deng, Huan; Chen, Lihui; Xiao, Yong; Zhao, Feng

2013-03-01

Biofilms are the core component of bioelectrochemical systems (BESs). To understand the polarization effects on biocathode performance of BES, dissolved oxygen concentrations, pHs and oxidation-reduction potentials of biofilm microenvironments were determined in situ. The results showed that lower polarization potentials resulted in the generation of larger currents and higher pH values, as well as the consumption of more oxygen. Oxidation-reduction potentials of biofilms were mainly affected by polarization potentials of the electrode rather than the concentration of dissolved oxygen or pH value, and its changes in the potentials corresponded to the electric field distribution of the electrode surface. The results demonstrated that a sufficient supply of dissolved oxygen and pH control of the biocathode are necessary to obtain optimal performance of BESs; a lower polarization potential endowed microorganisms with a higher electrochemical activity. Copyright © 2012 Elsevier Ltd. All rights reserved.

Simulation of hydrodynamics, temperature, and dissolved oxygen in Table Rock Lake, Missouri, 1996-1997

USGS Publications Warehouse

Green, W. Reed; Galloway, Joel M.; Richards, Joseph M.; Wesolowski, Edwin A.

2003-01-01

Outflow from Table Rock Lake and other White River reservoirs support a cold-water trout fishery of substantial economic yield in south-central Missouri and north-central Arkansas. The Missouri Department of Conservation has requested an increase in existing minimum flows through the Table Rock Lake Dam from the U.S. Army Corps of Engineers to increase the quality of fishable waters downstream in Lake Taneycomo. Information is needed to assess the effect of increased minimum flows on temperature and dissolved- oxygen concentrations of reservoir water and the outflow. A two-dimensional, laterally averaged, hydrodynamic, temperature, and dissolved-oxygen model, CE-QUAL-W2, was developed and calibrated for Table Rock Lake, located in Missouri, north of the Arkansas-Missouri State line. The model simulates water-surface elevation, heat transport, and dissolved-oxygen dynamics. The model was developed to assess the effects of proposed increases in minimum flow from about 4.4 cubic meters per second (the existing minimum flow) to 11.3 cubic meters per second (the increased minimum flow). Simulations included assessing the effect of (1) increased minimum flows and (2) increased minimum flows with increased water-surface elevations in Table Rock Lake, on outflow temperatures and dissolved-oxygen concentrations. In both minimum flow scenarios, water temperature appeared to stay the same or increase slightly (less than 0.37 ?C) and dissolved oxygen appeared to decrease slightly (less than 0.78 mg/L) in the outflow during the thermal stratification season. However, differences between the minimum flow scenarios for water temperature and dissolved- oxygen concentration and the calibrated model were similar to the differences between measured and simulated water-column profile values.

Effect of dissolved oxygen on nitrate removal using polycaprolactone as an organic carbon source and biofilm carrier in fixed-film denitrifying reactors.

PubMed

Luo, Guozhi; Xu, Guimei; Gao, Jinfang; Tan, Hongxin

2016-05-01

Nitrate-nitrogen (NO3(-)-N) always accumulates in commercial recirculating aquaculture systems (RASs) with aerobic nitrification units. The ability to reduce NO3(-)-N consistently and confidently could help RASs to become more sustainable. The rich dissolved oxygen (DO) content and sensitive organisms stocked in RASs increase the difficulty of denitrifying technology. A denitrifying process using biologically degradable polymers as an organic carbon source and biofilm carrier was proposed because of its space-efficient nature and strong ability to remove NO3(-)-N from RASs. The effect of dissolved oxygen (DO) levels on heterotrophic denitrification in fixed-film reactors filled with polycaprolactone (PCL) was explored in the current experiment. DO conditions in the influent of the denitrifying reactors were set up as follows: the anoxic treatment group (Group A, average DO concentration of 0.28±0.05mg/L), the low-oxygen treatment DO group (Group B, average DO concentration of 2.50±0.24mg/L) and the aerated treatment group (Group C, average DO concentration of 5.63±0.57mg/L). Feeding with 200mg/L of NO3(-)-N, the NO3(-)-N removal rates were 1.53, 1.60 and 1.42kg/m(3) PCL/day in Groups A, B and C, respectively. No significant difference in NO3(-)-N removal rates was observed among the three treatments. It was concluded that the inhibitory effects of DO concentrations lower than 6mg/L on heterotrophic denitrification in the fixed-film reactors filled with PCL can be mitigated. Copyright © 2015. Published by Elsevier B.V.

Pulsating potentiometric titration technique for assay of dissolved oxygen in water at trace level.

PubMed

Sahoo, P; Ananthanarayanan, R; Malathi, N; Rajiniganth, M P; Murali, N; Swaminathan, P

2010-06-11

A simple but high performance potentiometric titration technique using pulsating sensors has been developed for assay of dissolved oxygen (DO) in water samples down to 10.0 microg L(-1) levels. The technique involves Winkler titration chemistry, commonly used for determination of dissolved oxygen in water at mg L(-1) levels, with modification in methodology for accurate detection of end point even at 10.0 microg L(-1) levels DO present in the sample. An indigenously built sampling cum pretreatment vessel has been deployed for collection and chemical fixing of dissolved oxygen in water samples from flowing water line without exposure to air. A potentiometric titration facility using pulsating sensors developed in-house is used to carry out titration. The power of the titration technique has been realised in estimation of very dilute solution of iodine equivalent to 10 microg L(-1) O(2). Finally, several water samples containing dissolved oxygen from mg L(-1) to microg L(-1) levels were successfully analysed with excellent reproducibility using this new technique. The precision in measurement of DO in water at 10 microg L(-1) O(2) level is 0.14 (n=5), RSD: 1.4%. Probably for the first time a potentiometric titration technique has been successfully deployed for assay of dissolved oxygen in water samples at 10 microg L(-1) levels. Copyright 2010 Elsevier B.V. All rights reserved.

Emerging climate change signals in the interior ocean oxygen content

NASA Astrophysics Data System (ADS)

Tjiputra, Jerry; Goris, Nadine; Schwinger, Jörg; Lauvset, Siv

2017-04-01

Earth System Models (ESMs) indicate that human-induced climate change will introduce spatially heterogeneous modifications of dissolved oxygen in the North Atlantic. In the upper ocean, an increase (decrease) is predicted at low (high) latitude. Oxygen increase is driven by a reduction of the oxygen consumption for biological remineralization while warming-induced reduction in air-sea fluxes and increase in remineralization due to weaker overturning circulation lead to the projected decrease. In the interior ocean, modifications in the apparent oxygen utilization (AOU) dominate the overall oxygen changes. Moreover, for the southern subpolar gyre, both observations and model hindcast indicate a close relationship between interior ocean oxygen and the subpolar gyre index. Over the 21st century, all ESMs consistently project a steady weakening of this index and consequently the oxygen. Our finding shows that climate change-induced oxygen depletion in the interior has likely occurred and can already be detected. Nevertheless, considering the observational uncertainties, we show that in the proximity of southern subpolar gyre the projected interior trend is sufficiently large enough for early detection.

An experimental study on the cavitation of water with dissolved gases

NASA Astrophysics Data System (ADS)

Li, Buxuan; Gu, Youwei; Chen, Min

2017-12-01

Cavitation inception is generally determined by the tensile strengths of liquids. Investigations on the tensile strength of water, which is essential in many fields, will help understand the promotion/prevention of cavitation and related applications in water. Previous experimental studies, however, vary in their conclusions about the value of tensile strength of water; the difference is commonly attributed to the existence of impurities in water. Dissolved gases, especially oxygen and nitrogen from the air, are one of the most common kinds of impurities in water. The influence of these gases on the tensile strength of water is still unclear. This study investigated the effects of dissolved gases on water cavitation through experiments. Cavitation in water is generated by acoustic method. Water samples are prepared with dissolved oxygen and nitrogen in different gas concentrations. Results show that under the same temperature, the tensile strength of water with dissolved oxygen or nitrogen decreases with increased gas concentration compared with that of ultrapure water. Under the same gas concentration and temperature, water with dissolved oxygen shows a lower tensile strength than that with dissolved nitrogen. Possible reasons of these results are also discussed.

Distribution of dissolved and labile particulate trace metals in the overlying bottom water in the Vistula River plume (southern Baltic Sea).

PubMed

Sokolowski, A; Wolowicz, M; Hummel, H

2001-10-01

Overlying bottom water samples were collected in the Vistula River plume, southern Baltic Sea, (Poland) and analysed for dissolved and labile particulate (1 M HCl extractable) Cu, Pb, Zn, Mn, Fe and Ni, hydrological parameters being measured simultaneously. Particulate organic matter (POM), chlorophyll a and dissolved oxygen are key factors governing the chemical behaviour of the measured metal fractions. For the dissolved Cu, Pb, Zn, Fe and Ni two maxima, in the shallow and in the deeper part of the river plume, were found. In the shallow zone desorption from seaward fluxing metal-rich riverine particles account for markedly increased metal concentrations, as confirmed also by high particulate metal contents. For Pb, atmospheric inputs were also considered to have contributed to the elevated concentrations of dissolved Pb adjacent to the river mouth. In the deep zone desorption from detrital and/or resuspended particles by aerobic decomposition of organic material may be the main mechanism responsible for enrichment of particle-reactive metals (Cu, Pb, Zn) in the overyling bottom waters. The increased concentrations of dissolved Fe may have been due to reductive dissolution of Fe oxyhydroxides within the deep sediments by which dissolved Ni was released to the water. The distribution of Mn was related to dissolved oxygen concentrations, indicating that Mn is released to the water column under oxygen reduced conditions. However, Mn transfer to the dissolved phase from anoxic sediments in deeper part of the Vistula plume was hardly evidenced suggesting that benthic flux of Mn occurs under more severe reductive regime than is consistent with mobilization of Fe. Behaviour of Mn in a shallower part has been presumably affected by release from porewaters and by oxidization into less soluble species resulting in seasonal removal of this metal (e.g. in April) from the dissolved phase. The particulate fractions represented from about 6% (Ni) and 33% (Mn, Zn, Cu) to 80% (Fe) and 89% (Pb) of the total (labile particulate plus dissolved) concentrations. The affinity of the metals for particulate matter decreased in the following order: Pb > Fe > Zn > or = > Cu > Mn > Ni. Significant relationships between particulate Pb-Zn-Cu reflected the affinity of these metals for organic matter, and the significant relationship between Ni-Fe reflected the adsorption of Ni onto Fe-Mn oxyhydroxides. A comparison of metal concentrations with data from other similar areas revealed that the river plume is somewhat contaminated with Cu, Pb and Zn which is in agreement with previous findings on anthropogenic origin of these metals in the Polish zone of southern Baltic Sea.

Response of Benthic Foraminiferal Size to Oxygen Concentration in Antarctic Sediment Cores

NASA Astrophysics Data System (ADS)

Guo, D.; Keating-Bitonti, C.; Payne, J.

2014-12-01

Oxygen availability is important for biological reactions and the demand of oxygen is determined by the size of the organism. Few marine organisms can tolerate low oxygen conditions, but benthic foraminifera, a group of amoeboid protists that are highly sensitive to environmental factors, are known to live in these conditions. Benthic foraminifera may be able to live in oxygen stressed environments by changing the size and shape of their test. Low oxygen concentrations should favor smaller, thinner-shelled, flattened test morphologies. We hypothesize that the volume-to-surface area ratio of benthic foraminifera will decrease with decreasing dissolved oxygen concentrations. To test this hypothesis, we picked two calcareous species (Epistominella exigua and Cassulinoides porrectus) and one agglutinated species (Portatrochammina antarctica) from three sediment cores collected from Explorer's Cove, Antarctica. Starting at the sediment-water interface, each core spans approximately 5-8 cm of depth. Profiles of dissolved oxygen concentrations were measured at the time of collection. At specific depths within the cores, we measured the three dimensions of picked foraminiferal tests using NIS-Elements. We calculated the volume and surface area of the tests assuming the shape of the foraminifers was an ellipsoid. The size trends of E. exigua confirm our hypothesis that the test volume-to-surface area ratios correlate positively with dissolved oxygen concentrations (p-value < 0.001). However, the size trends of the other species refute our hypothesis: P. antarctica shows no correlation and C. porrectus shows a negative correlation (p-value < 0.001) to dissolved oxygen concentrations. Thus, our results show that the change in size in response to variations in dissolved oxygen concentrations is species dependent. Moreover, we find that calcareous species are more sensitive to oxygen fluctuations than agglutinated species.

Theoretical technique for predicting the cumulative impact of iron and manganese oxidation in streams receiving discharge from coal mines

USGS Publications Warehouse

Bobay, Keith E.

1986-01-01

Two U.S. Geological Survey computer programs are modified and linked to predict the cumulative impact of iron and manganese oxidation in coal-mine discharge water on the dissolved chemical quality of a receiving stream. The coupled programs calculate the changes in dissolved iron, dissolved manganese, and dissolved oxygen concentrations; alkalinity; and, pH of surface water downstream from the point of discharge. First, the one-dimensional, stead-state stream, water quality program uses a dissolved oxygen model to calculate the changes in concentration of elements as a function of the chemical reaction rates and time-of-travel. Second, a program (PHREEQE) combining pH, reduction-oxidation potential, and equilibrium equations uses an aqueous-ion association model to determine the saturation indices and to calculate pH; it then mixes the discharge with a receiving stream. The kinetic processes of the first program dominate the system, whereas the equilibrium thermodynamics of the second define the limits of the reactions. A comprehensive test of the technique was not possible because a complete set of data was unavailable. However, the cumulative impact of representative discharges from several coal mines on stream quality in a small watershed in southwestern Indiana was simulated to illustrate the operation of the technique and to determine its sensitivity to changes in physical, chemical, and kinetic parameters. Mine discharges averaged 2 cu ft/sec, with a pH of 6.0, and concentrations of 7.0 mg/L dissolved iron, 4.0 mg/L dissolved manganese, and 8.08 mg/L dissolved oxygen. The receiving stream discharge was 2 cu ft/sec, with a pH of 7.0, and concentrations of 0.1 mg/L dissolved iron, 0.1 mg/L dissolved manganese, and 8.70 mg/L dissolved oxygen. Results of the simulations indicated the following cumulative impact on the receiving stream from five discharges as compared with the effect from one discharge: 0.30 unit decrease in pH, 1.82 mg/L increase in dissolved iron, 1.50 mg/L increase in dissolved manganese, and 0.24 mg/L decrease in dissolved oxygen concentration.

Patterns of dissolved oxygen dynamics in a Pacific Northwest slough and tide channel.

EPA Science Inventory

Pacific Northwest (PNW) estuaries and tide channels are habitats or migratory corridors for societally prized salmonids. These fish have high oxygen requirements, and an adequate level of dissolved oxygen is considered an important gauge of a PNW water body’s condition. W...

Nitrogen fixation in the activated sludge treatment of thermomechanical pulping wastewater: effect of dissolved oxygen.

PubMed

Slade, A H; Anderson, S M; Evans, B G

2003-01-01

N-ViroTech, a novel technology which selects for nitrogen-fixing bacteria as the bacteria primarily responsible for carbon removal, has been developed to treat nutrient limited wastewaters to a high quality without the addition of nitrogen, and only minimal addition of phosphorus. Selection of the operating dissolved oxygen level to maximise nitrogen fixation forms a key component of the technology. Pilot scale activated sludge treatment of a thermomechanical pulping wastewater was carried out in nitrogen-fixing mode over a 15 month period. The effect of dissolved oxygen was studied at three levels: 14% (Phase 1), 5% (Phase 2) and 30% (Phase 3). The plant was operated at an organic loading of 0.7-1.1 kg BOD5/m3/d, a solids retention time of approximately 10 d, a hydraulic retention time of 1.4 d and a F:M ratio of 0.17-0.23 mg BOD5/mg VSS/d. Treatment performance was very stable over the three dissolved oxygen operating levels. The plant achieved 94-96% BOD removal, 82-87% total COD removal, 79-87% soluble COD removal, and >99% total extractives removal. The lowest organic carbon removals were observed during operation at 30% DO but were more likely to be due to phosphorus limitation than operation at high dissolved oxygen, as there was a significant decrease in phosphorus entering the plant during Phase 3. Discharge of dissolved nitrogen, ammonium and oxidised nitrogen were consistently low (1.1-1.6 mg/L DKN, 0.1-0.2 mg/L NH4+-N and 0.0 mg/L oxidised nitrogen). Discharge of dissolved phosphorus was 2.8 mg/L, 0.1 mg/L and 0.6 mg/L DRP in Phases 1, 2 and 3 respectively. It was postulated that a population of polyphosphate accumulating bacteria developed during Phase 1. Operation at low dissolved oxygen during Phase 2 appeared to promote biological phosphorus uptake which may have been affected by raising the dissolved oxygen to 30% in Phase 3. Total nitrogen and phosphorus discharge was dependent on efficient secondary clarification, and improved over the course of the study as suspended solids discharge improved. Nitrogen fixation was demonstrated throughout the study using an acetylene reduction assay. Based on nitrogen balances around the plant, there was a 55, 354 and 98% increase in nitrogen during Phases 1, 2 and 3 respectively. There was a significant decrease in phosphorus between Phases 1 and 2, and Phase 3 of the study, as well as a significant increase in nitrogen between Phases 2 and 3 which masked the effect of changing the dissolved oxygen. Operation at low dissolved oxygen appeared to confer a competitive advantage to the nitrogen-fixing bacteria.

[Determination of polyphenolic complex in wines by electrochemical methods and using the enzymes tyrosinase and laccase].

PubMed

Shleev, S V; Chekanova, S A; Koroleva, O V; Stepanova, E V; Telegin, Iu A; Sen'kina, Z E

2004-01-01

Several red wines were studied to find a correlation between physicochemical parameters characterizing the antioxidant status of wine and total content of phenols in samples. The content of dissolved oxygen (its value varied from 0.75 to 3.28 mg/ml), pH (3.10-3.63), redox potential (-186 to -106 mV), mass concentration of free and total sulfur dioxide (10-30 and 36-200 mg/dm3, respectively), absorption spectra, and total phenol content were determined. The wines fell into two main groups-with a relatively low (1850-2050 mg/dm3) and high (2300-2900 mg/dm3) contents of polyphenols. It was demonstrated that physicochemical parameters (except for the content of sulfur dioxide) correlate with the total phenol content in the wines studied.

Techniques for the conversion to carbon dioxide of oxygen from dissolved sulfate in thermal waters

USGS Publications Warehouse

Nehring, N.L.; Bowen, P.A.; Truesdell, A.H.

1977-01-01

The fractionation of oxygen isotopes between dissolved sulfate ions and water provides a useful geothermometer for geothermal waters. The oxygen isotope composition of dissolved sulfate may also be used to indicate the source of the sulfate and processes of formation. The methods described here for separation, purification and reduction of sulfate to prepare carbon dioxide for mass spectrometric analysis are modifications of methods by Rafter (1967), Mizutani (1971), Sakai and Krouse (1971), and Mizutani and Rafter (1969). ?? 1976.

Reduction of Dissolved Oxygen at a Copper Rotating Disc Electrode

ERIC Educational Resources Information Center

Kear, Gareth; Albarran, Carlos Ponce-de-Leon; Walsh, Frank C.

2005-01-01

Undergraduates from chemical engineering, applied chemistry, and environmental science courses, together with first-year postgraduate research students in electrochemical technology, are provided with an experiment that demonstrates the reduction of dissolved oxygen in aerated seawater at 25°C. Oxygen reduction is examined using linear sweep…

Patterns of dissolved oxygen dynamics in a Pacific Northwest slough and tide channel - CERF 2015

EPA Science Inventory

Pacific Northwest (PNW) estuaries and tide channels are habitats or migratory corridors for societally prized salmonids. These fish have high oxygen requirements, and an adequate level of dissolved oxygen is considered an important gauge of a PNW water body’s condition. W...

Simulation of Temperature, Nutrients, Biochemical Oxygen Demand, and Dissolved Oxygen in the Catawba River, South Carolina, 1996-97

USGS Publications Warehouse

Feaster, Toby D.; Conrads, Paul; Guimaraes, Wladmir B.; Sanders, Curtis L.; Bales, Jerad D.

2003-01-01

Time-series plots of dissolved-oxygen concentrations were determined for various simulated hydrologic and point-source loading conditions along a free-flowing section of the Catawba River from Lake Wylie Dam to the headwaters of Fishing Creek Reservoir in South Carolina. The U.S. Geological Survey one-dimensional dynamic-flow model, BRANCH, was used to simulate hydrodynamic data for the Branched Lagrangian Transport Model. Waterquality data were used to calibrate the Branched Lagrangian Transport Model and included concentrations of nutrients, chlorophyll a, and biochemical oxygen demand in water samples collected during two synoptic sampling surveys at 10 sites along the main stem of the Catawba River and at 3 tributaries; and continuous water temperature and dissolved-oxygen concentrations measured at 5 locations along the main stem of the Catawba River. A sensitivity analysis of the simulated dissolved-oxygen concentrations to model coefficients and data inputs indicated that the simulated dissolved-oxygen concentrations were most sensitive to watertemperature boundary data due to the effect of temperature on reaction kinetics and the solubility of dissolved oxygen. Of the model coefficients, the simulated dissolved-oxygen concentration was most sensitive to the biological oxidation rate of nitrite to nitrate. To demonstrate the utility of the Branched Lagrangian Transport Model for the Catawba River, the model was used to simulate several water-quality scenarios to evaluate the effect on the 24-hour mean dissolved-oxygen concentrations at selected sites for August 24, 1996, as simulated during the model calibration period of August 23 27, 1996. The first scenario included three loading conditions of the major effluent discharges along the main stem of the Catawba River (1) current load (as sampled in August 1996); (2) no load (all point-source loads were removed from the main stem of the Catawba River; loads from the main tributaries were not removed); and (3) fully loaded (in accordance with South Carolina Department of Health and Environmental Control National Discharge Elimination System permits). Results indicate that the 24-hour mean and minimum dissolved-oxygen concentrations for August 24, 1996, changed from the no-load condition within a range of - 0.33 to 0.02 milligram per liter and - 0.48 to 0.00 milligram per liter, respectively. Fully permitted loading conditions changed the 24-hour mean and minimum dissolved-oxygen concentrations from - 0.88 to 0.04 milligram per liter and - 1.04 to 0.00 milligram per liter, respectively. A second scenario included the addition of a point-source discharge of 25 million gallons per day to the August 1996 calibration conditions. The discharge was added at S.C. Highway 5 or at a location near Culp Island (about 4 miles downstream from S.C. Highway 5) and had no significant effect on the daily mean and minimum dissolved-oxygen concentration. A third scenario evaluated the phosphorus loading into Fishing Creek Reservoir; four loading conditions of phosphorus into Catawba River were simulated. The four conditions included fully permitted and actual loading conditions, removal of all point sources from the Catawba River, and removal of all point and nonpoint sources from Sugar Creek. Removing the point-source inputs on the Catawba River and the point and nonpoint sources in Sugar Creek reduced the organic phosphorus and orthophosphate loadings to Fishing Creek Reservoir by 78 and 85 percent, respectively.

Long-term simulations of dissolved oxygen concentrations in Lake Trout lakes

NASA Astrophysics Data System (ADS)

Jabbari, A.; Boegman, L.; MacKay, M.; Hadley, K.; Paterson, A.; Jeziorski, A.; Nelligan, C.; Smol, J. P.

2016-02-01

Lake Trout are a rare and valuable natural resource that are threatened by multiple environmental stressors. With the added threat of climate warming, there is growing concern among resource managers that increased thermal stratification will reduce the habitat quality of deep-water Lake Trout lakes through enhanced oxygen depletion. To address this issue, a three-part study is underway, which aims to: analyze sediment cores to understand the past, develop empirical formulae to model the present and apply computational models to forecast the future. This presentation reports on the computational modeling efforts. To this end, a simple dissolved oxygen sub-model has been embedded in the one-dimensional bulk mixed-layer thermodynamic Canadian Small Lake Model (CSLM). This model is currently being incorporated into the Canadian Land Surface Scheme (CLASS), the primary land surface component of Environment Canada's global and regional climate modelling systems. The oxygen model was calibrated and validated by hind-casting temperature and dissolved oxygen profiles from two Lake Trout lakes on the Canadian Shield. These data sets include 5 years of high-frequency (10 s to 10 min) data from Eagle Lake and 30 years of bi-weekly data from Harp Lake. Initial results show temperature and dissolved oxygen was predicted with root mean square error <1.5 °C and <3 mgL-1, respectively. Ongoing work is validating the model, over climate-change relevant timescales, against dissolved oxygen reconstructions from the sediment cores and predicting future deep-water temperature and dissolved oxygen concentrations in Canadian Lake Trout lakes under future climate change scenarios. This model will provide a useful tool for managers to ensure sustainable fishery resources for future generations.

First Autonomous Recording of in situ Dissolved Oxygen from Free-ranging Fish

NASA Astrophysics Data System (ADS)

Coffey, D.; Holland, K.

2016-02-01

Biologging technology has enhanced our understanding of the ecology of marine animals and has been central to identifying how oceanographic conditions drive patterns in their distribution and behavior. Among these environmental influences, there is increasing recognition of the impact of dissolved oxygen on the distribution of marine animals. Understanding of the impact of oxygen on vertical and horizontal movements would be advanced by contemporaneous in situ measurements of dissolved oxygen from animal-borne sensors instead of relying on environmental data that may not have appropriate spatial or temporal resolution. Here we demonstrate the capabilities of dissolved oxygen pop-up satellite archival tags (DO-PATs) by presenting the results from calibration experiments and trial deployments of two prototype tags on bluntnose sixgill sharks (Hexanchus griseus). The DO-PATs provided fast, accurate, and stable measurements in calibration trials and demonstrated high correlation with vertical profiles obtained via traditional ship-borne oceanographic instruments. Deployments on bluntnose sixgill sharks recorded oxygen saturations as low as 9.4% and effectively captured the oceanography of the region when compared with World Ocean Atlas 2013 values. This is the first study to use an animal-borne device to autonomously measure and record in situ dissolved oxygen saturation from non-air-breathing marine animals. The DO-PATs maintained consistency over time and yielded measurements equivalent to industry standards for environmental sampling. Acquiring contemporaneous in situ measurements of dissolved oxygen saturation alongside temperature and depth data will greatly improve our ability to investigate the spatial ecology of marine animals and make informed predictions of the impacts of global climate change. The information returned from DO-PATs is relevant not only to the study of the ecology of marine animals but will also become a useful new tool for investigating the physical structure of the oceans.

Effects of dissolved oxygen on performance and microbial community structure in a micro-aerobic hydrolysis sludge in situ reduction process.

PubMed

Niu, Tianhao; Zhou, Zhen; Shen, Xuelian; Qiao, Weimin; Jiang, Lu-Man; Pan, Wei; Zhou, Jijun

2016-03-01

A sludge process reduction activated sludge (SPRAS), with a sludge process reduction module composed of a micro-aerobic tank and a settler positioned before conventional activated sludge process, showed good performance of pollutant removal and sludge reduction. Two SPRAS systems were operated to investigate effects of micro-aeration on sludge reduction performance and microbial community structure. When dissolved oxygen (DO) concentration in the micro-aerobic tank decreased from 2.5 (SPH) to 0.5 (SPL) mg/L, the sludge reduction efficiency increased from 42.9% to 68.3%. Compared to SPH, activated sludge in SPL showed higher contents of extracellular polymeric substances and dissolved organic matter. Destabilization of floc structure in the settler, and cell lysis in the sludge process reduction module were two major reasons for sludge reduction. Illumina-MiSeq sequencing showed that microbial diversity decreased under high DO concentration. Proteobacteria, Bacteroidetes and Chloroflexi were the most abundant phyla in the SPRAS. Specific comparisons down to the class and genus level showed that fermentative, predatory and slow-growing bacteria in SPL community were more abundant than in SPH. The results revealed that micro-aeration in the SPRAS improved hydrolysis efficiency and enriched fermentative and predatory bacteria responsible for sludge reduction. Copyright © 2016 Elsevier Ltd. All rights reserved.

In situ analysis of oxygen consumption and diffusive transport in high-temperature acidic iron-oxide microbial mats.

PubMed

Bernstein, Hans C; Beam, Jacob P; Kozubal, Mark A; Carlson, Ross P; Inskeep, William P

2013-08-01

The role of dissolved oxygen as a principal electron acceptor for microbial metabolism was investigated within Fe(III)-oxide microbial mats that form in acidic geothermal springs of Yellowstone National Park (USA). Specific goals of the study were to measure and model dissolved oxygen profiles within high-temperature (65-75°C) acidic (pH = 2.7-3.8) Fe(III)-oxide microbial mats, and correlate the abundance of aerobic, iron-oxidizing Metallosphaera yellowstonensis organisms and mRNA gene expression levels to Fe(II)-oxidizing habitats shown to consume oxygen. In situ oxygen microprofiles were obtained perpendicular to the direction of convective flow across the aqueous phase/Fe(III)-oxide microbial mat interface using oxygen microsensors. Dissolved oxygen concentrations dropped from ∼ 50-60 μM in the bulk-fluid/mat surface to below detection (< 0.3 μM) at a depth of ∼ 700 μm (∼ 10% of the total mat depth). Net areal oxygen fluxes into the microbial mats were estimated to range from 1.4-1.6 × 10(-4)  μmol cm(-2)  s(-1) . Dimensionless parameters were used to model dissolved oxygen profiles and establish that mass transfer rates limit the oxygen consumption. A zone of higher dissolved oxygen at the mat surface promotes Fe(III)-oxide biomineralization, which was supported using molecular analysis of Metallosphaera yellowstonensis 16S rRNA gene copy numbers and mRNA expression of haem Cu oxidases (FoxA) associated with Fe(II)-oxidation. © 2013 John Wiley & Sons Ltd and Society for Applied Microbiology.

Effects of dilution on dissolved oxygen depletion and microbial populations in the biochemical oxygen demand determination.

PubMed

Seo, Kyo Seong; Chang, Ho Nam; Park, Joong Kon; Choo, Kwang-Ho

2007-09-01

The biochemical oxygen demand (BOD) value is still a key parameter that can determine the level of organics, particularly the content of biodegradable organics in water. In this work, the effects of sample dilution, which should be done inevitably to get appropriate dissolved oxygen (DO) depletion, on the measurement of 5-day BOD (BOD(5)), was investigated with and without seeding using natural and synthetic water. The dilution effects were also evaluated for water samples taken in different seasons such as summer and winter because water temperature can cause a change in the types of microbial species, thus leading to different oxygen depletion profiles during BOD testing. The predation phenomenon between microbial cells was found to be dependent on the inorganic nutrients and carbon sources, showing a change in cell populations according to cell size after 5-day incubation. The dilution of water samples for BOD determination was linked to changes in the environment for microbial growth such as nutrition. The predation phenomenon between microbial cells was more important with less dilution. BOD(5) increased with the specific amount of inorganic nutrient per microbial mass when the natural water was diluted. When seeding was done for synthetic water samples, the seed volume also affected BOD due to the rate of organic uptake by microbes. BOD(5) increased with the specific bacterial population per organic source supplied at the beginning of BOD measurement. For more accurate BOD measurements, specific guidelines on dilution should be established.

Effect of oxidation on transport properties of zirconium-1% niobium alloy

NASA Astrophysics Data System (ADS)

Peletsky, V. E.; Musayeva, Z. A.

1995-11-01

The thermal conductivity and electrical resistivity of zirconium-1 wt% niobium samples were measured before and after the process of their oxidation in air. A special procedure was used to dissolve the gas and to smooth out its concentration in the alloy. The basic experiments were performed under high vacuum under steady-state temperature conditions. The temperature range was 300 1600 K. for the pure alloy and 300 1100 K for the samples containing oxygen. It was found that the thermal conductivity—oxygen concentration relation reverses its sign from negative at low and middle temperatures to positive at temperatures above 900 K. The relation between the electrical resistivity and the oxygen content does not show this feature. The Lorenz function was found to have an anomalous temperature dependence.

The Measurement of Dissolved Oxygen

ERIC Educational Resources Information Center

Thistlethwayte, D.; And Others

1974-01-01

Describes an experiment in environmental chemistry which serves to determine the dissolved oxygen concentration in both fresh and saline water. Applications of the method at the undergraduate and secondary school levels are recommended. (CC)

Use of diverse geochemical data sets to determine sources and sinks of nitrate and methane in groundwater, Garfield County, Colorado, 2009

USGS Publications Warehouse

McMahon, P.B.; Thomas, J.C.; Hunt, A.G.

2011-01-01

Previous water-quality assessments reported elevated concentrations of nitrate and methane in water from domestic wells screened in shallow zones of the Wasatch Formation, Garfield County, Colorado. In 2009, the U.S. Geological Survey, in cooperation with the Colorado Department of Public Health and Environment, analyzed samples collected from 26 domestic wells for a diverse set of geochemical tracers for the purpose of determining sources and sinks of nitrate and methane in groundwater from the Wasatch Formation. Nitrate concentrations ranged from less than 0.04 to 6.74 milligrams per liter as nitrogen (mg/L as N) and were significantly lower in water samples with dissolved-oxygen concentrations less than 0.5 mg/L than in samples with dissolved-oxygen concentrations greater than or equal to 0.5 mg/L. Chloride/bromide mass ratios and tracers of groundwater age (tritium, chlorofluorocarbons, and sulfur hexafluoride) indicate that septic-system effluent or animal waste was a source of nitrate in some young groundwater (less than 50 years), although other sources such as fertilizer also may have contributed nitrate to the groundwater. Nitrate and nitrogen gas (N2) concentrations indicate that denitrification was the primary sink for nitrate in anoxic groundwater, removing 99 percent of the original nitrate content in some samples that had nitrate concentrations greater than 10 mg/L as N at the time of recharge. Methane concentrations ranged from less than 0.0005 to 32.5 mg/L and were significantly higher in water samples with dissolved-oxygen concentrations less than 0.5 mg/L than in samples with dissolved-oxygen concentrations greater than or equal to 0.5 mg/L. High methane concentrations (greater than 1 mg/L) in some samples were biogenic in origin and appeared to be derived from a relatively deep source on the basis of helium concentrations and isotopic data. One such sample had water-isotopic and major-ion compositions similar to that of produced water from the underlying Mesaverde Group, which was the primary natural-gas producing interval in the study area. Methane in the Mesaverde Group was largely thermogenic in origin so biogenic methane in the sample probably was derived from deeper zones in the Wasatch Formation. The primary methane sink in the aquifer appeared to be methane oxidation on the basis of dissolved-oxygen and methane concentrations and methane isotopic data. The diverse data sets used in this study enhance previous water-quality assessments by providing new and more complete insights into the sources and sinks of nitrate and methane in groundwater. Field measurements of dissolved oxygen in groundwater were useful indicators of the Wasatch Formation's vulnerability to nitrate and methane contamination or enrichment. Results from this study also provide new evidence for the movement of water, ions, and gases into the shallow Wasatch Formation from sources such as the Mesaverde Group and deeper Wasatch Formation.

The Antioxidation Mechanism of Polydimethylsiloxane in Oil.

PubMed

Yawata, Miho; Satoh, Tohru; Iwahashi, Maiko; Hori, Ryuji; Takeuchi, Shigeo; Shiramasa, Hiroshi; Totani, Nagao

2015-01-01

Strong and stable antioxidation effects of polydimethylsiloxane (PDMS) are widely accepted and utilized in commercial frying oil; however, the mechanism is not fully established. On the other hand, canola oil contains about 700 ppm (mg/kg-oil) of the natural antioxidant, tocopherol. Canola oil containing 0, 1 and 10 ppm added PDMS was heated at 180°C for 1 h under stirring, then left for 2-3 days at room temperature; this treatment was repeated 5 times. Compared to pure canola oil, PDMS-containing canola oil exhibited remarkably lower peroxide, p-anisidine and acid values, a lower decrease in tocopherol content but a higher oxygen content during the heating experiments, implicating low oxygen consumption for the oxidation. While PDMS has not been known to exhibit antioxidative effects at ambient temperatures, the present results show that PDMS prevents autoxidation as well as thermal oxidation. In addition, PDMS, not tocopherols, provided the major antioxidative effect during intermittent heating, and the decrease of tocopherols was significantly inhibited by PDMS. Phase contrast microscopy confirmed that PDMS contained in canola oil was suspended as particles. Also, the oxygen content in standing PDMS-containing canola oil decreased as the depth of oil increased, corresponding to the PDMS distribution, which also decreased as the depth of oil increased. Moreover, PDMS had a higher affinity for oxygen than canola oil in a mixture of canola oil/PDMS, 1:1 v/v. Thus, it is suggested that PDMS restricted the behavior of oxygen dissolved in canola oil by attracting oxygen in and around the PDMS particles, which is wholly different from the radical scavenging antioxidation of tocopherol.

Water-Quality Monitoring in Response to Young-of-the-Year Smallmouth Bass (Micropterus dolomieu) Mortality in the Susquehanna River and Major Tributaries, Pennsylvania: 2008

USGS Publications Warehouse

Chaplin, Jeffrey J.; Crawford, J. Kent; Brightbill, Robin A.

2009-01-01

Mortalities of young-of-the-year (YOY) smallmouth bass (Micropterus dolomieu) recently have occurred in the Susquehanna River due to Flavobacterium columnare, a bacterium that typically infects stressed fish. Stress factors include but are not limited to elevated water temperature and low dissolved oxygen during times critical for survival and development of smallmouth bass (May 1 through July 31). The infections were first discovered in the Susquehanna River and major tributaries in the summer months of 2005 but also were prevalent in 2007. The U.S. Geological Survey, Pennsylvania Fish and Boat Commission, Pennsylvania Department of Environmental Protection, and PPL Corporation worked together to monitor dissolved oxygen, water temperature, pH, and specific conductance on a continuous basis at seven locations from May through mid October 2008. In addition, nutrient concentrations, which may affect dissolved-oxygen concentrations, were measured once in water and streambed sediment at 25 locations. Data from water-quality meters (sondes) deployed as pairs showed daily minimum dissolved-oxygen concentration at YOY smallmouth-bass microhabitats in the Susquehanna River at Clemson Island and the Juniata River at Howe Township Park were significantly lower (p-value < 0.0001) than nearby main-channel habitats. The average daily minimum dissolved-oxygen concentration during the critical period (May 1-July 31) was 1.1 mg/L lower in the Susquehanna River microhabitat and 0.3 mg/L lower in the Juniata River. Daily minimum dissolved-oxygen concentrations were lower than the applicable national criterion (5.0 mg/L) in microhabitat in the Susquehanna River at Clemson Island on 31 days (of 92 days in the critical period) compared to no days in the corresponding main-channel habitat. In the Juniata River, daily minimum dissolved-oxygen concentration in the microhabitat was lower than 5.0 mg/L on 20 days compared to only 5 days in the main-channel habitat. The maximum time periods that dissolved oxygen was less than 5.0 mg/L in microhabitats of the Susquehanna and Juniata Rivers were 8.5 and 5.5 hours, respectively. Dissolved-oxygen concentrations lower than the national criterion generally occurred during nighttime and early-morning hours between midnight and 0800. The lowest instantaneous dissolved-oxygen concentrations measured in microhabitats during the critical period were 3.3 mg/L for the Susquehanna River at Clemson Island (June 11, 2008) and 4.1 mg/L for the Juniata River at Howe Township Park (July 22, 2008). Comparison of 2008 data to available continuous-monitoring data from 1974 to 1979 in the Susquehanna River at Harrisburg, Pa., indicates the critical period of 2008 had an average daily mean dissolved-oxygen concentration that was 1.1 mg/L lower (p-value < 0.0001) than in the 1970s and an average daily mean water temperature that was 0.8 deg C warmer (p-value = 0.0056). Streamflow was not significantly different (p-value = 0.0952) between the two time periods indicating that it is not a likely explanation for the differences in water quality. During the critical period in 2008, dissolved-oxygen concentrations were lower in the Susquehanna River at Harrisburg, Pa., than in the Delaware River at Trenton, N.J., or Allegheny River at Acmetonia near Pittsburgh, Pa. Daily minimum dissolved-oxygen concentrations were below the national criterion of 5.0 mg/L on 6 days during the critical period in the Susquehanna River at Harrisburg compared to no days in the Delaware River at Trenton and the Allegheny River at Acmetonia. Average daily mean water temperature in the Susquehanna River at Harrisburg was 1.8 deg C warmer than in the Delaware River at Trenton and 3.4 deg C warmer than in the Allegheny River at Acmetonia. These results indicate that any stress induced by dissolved oxygen or other environmental conditions is likely to be magnified by elevated temperature in the Susquehanna River at Harrisburg compared to the Delaw

Plasma corticosteroid dynamics in channel catfish, Ictalurus punctatus (Rafinesque), during and after oxygen depletion

USGS Publications Warehouse

Tomasso J.R., Davis; Parker, N.C.

1981-01-01

Plasma corticosteroid concentrations in channel catfish, Ictalurus punctatus, (normally 1.0 ± 0.3 μg/100 ml) increased significantly (to 5.9 ± 1.2μg/100 ml) in response to acute oxygen depletion and then returned to control levels within 30 min after the dissolved oxygen concentration was increased; however, a secondary increase in plasma corticosteroid levels was observed 6 h after exposure. Corticosteroid levels also increased in fish exposed to dissolved oxygen concentration of <0.2 mg/1 for three days. Methylene blue was not effective in preventing interrenal response to low dissolved oxygen. No diurnal plasma corticosteroid rhythm was observed in fish exposed to diurnal chemical rhythms of culture ponds.

Scaling oxygen microprofiles at the sediment interface of deep stratified waters

NASA Astrophysics Data System (ADS)

Schwefel, Robert; Hondzo, Miki; Wüest, Alfred; Bouffard, Damien

2017-02-01

Dissolved oxygen microprofiles at the sediment-water interface of Lake Geneva were measured concurrently with velocities 0.25 to 2 m above the sediment. The measurements and scaling analyses indicate dissolved oxygen fluctuations and turbulent fluxes in exceedance of molecular diffusion in the proximity of the sediment-water interface. The measurements allowed the parameterization of the turbulent diffusion as a function of the dimensionless height above the sediment and the turbulence above the sediment-water interface. Turbulent diffusion depended strongly on the friction velocity and differed from formulations reported in the literature that are based on concepts of turbulent and developed wall-bounded flows. The dissolved oxygen microprofiles and proposed parameterization of turbulent diffusion enable a foundation for the similarity scaling of oxygen microprofiles in proximity to the sediment. The proposed scaling allows the estimation of diffusive boundary layer thickness, oxygen flux, and oxygen microprofile distribution in the near-sediment boundary layer.

78 FR 59555 - Endangered and Threatened Wildlife and Plants; Designation of Critical Habitat for the Fluted...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-09-26

... physical and chemical water quality parameters (such as temperature, dissolved oxygen, pH, and conductivity... unknown. High temperatures can reduce dissolved oxygen concentrations in the water, which slows growth... encystment, increase oxygen consumption, reduce the speed in which they orient themselves in the substrate...

Modeling chlorophyll-a and dissolved oxygen concentration in tropical floodplain lakes (Paraná River, Brazil).

PubMed

Rocha, R R A; Thomaz, S M; Carvalho, P; Gomes, L C

2009-06-01

The need for prediction is widely recognized in limnology. In this study, data from 25 lakes of the Upper Paraná River floodplain were used to build models to predict chlorophyll-a and dissolved oxygen concentrations. Akaike's information criterion (AIC) was used as a criterion for model selection. Models were validated with independent data obtained in the same lakes in 2001. Predictor variables that significantly explained chlorophyll-a concentration were pH, electrical conductivity, total seston (positive correlation) and nitrate (negative correlation). This model explained 52% of chlorophyll variability. Variables that significantly explained dissolved oxygen concentration were pH, lake area and nitrate (all positive correlations); water temperature and electrical conductivity were negatively correlated with oxygen. This model explained 54% of oxygen variability. Validation with independent data showed that both models had the potential to predict algal biomass and dissolved oxygen concentration in these lakes. These findings suggest that multiple regression models are valuable and practical tools for understanding the dynamics of ecosystems and that predictive limnology may still be considered a powerful approach in aquatic ecology.

Impact of variability in coastal fog on photosynthesis and dissolved oxygen levels in shallow water habitats: Salmon Creek estuary case study

NASA Astrophysics Data System (ADS)

Largier, J. L.

2013-12-01

Coastal fog reduces available light levels that in turn reduce rates of photosynthesis and oxygen production. This effect can be seen in perturbations of the day-night production-respiration cycle that leads to increase and decrease in dissolved oxygen in shallow-water habitats. In well stratified coastal lagoons, a lower layer may be isolated from the atmosphere so that small changes in photosynthetically active radiation (PAR) are evident in perturbations of the typical day-night cycle of oxygen concentration. This effect is observed in the summertime, mouth-closed Salmon Creek Estuary, located in Sonoma County (California). Sub-diurnal fluctuations in dissolved oxygen in Salmon Creek Estuary correlate with deviations from the clear-sky diurnal cycle in PAR. Similar effects are observed in other estuaries and the process by which fog controls photosynthesis can be expected to occur throughout coastal California, although the effect may not be easily observable in data collected from open waters where mixing and bloom dynamics are likely to dominate temporal variability in biogenic properties like dissolved oxygen.

Effect of dissolved oxygen in alcoholic beverages and drinking water on alcohol elimination in humans.

PubMed

Rhee, Su-jin; Chae, Jung-woo; Song, Byung-jeong; Lee, Eun-sil; Kwon, Kwang-il

2013-02-01

Oxygen plays an important role in the metabolism of alcohol. An increased dissolved oxygen level in alcoholic beverages reportedly accelerates the elimination of alcohol. Therefore, we evaluated the effect of dissolved oxygen in alcohol and the supportive effect of oxygenated water on alcohol pharmacokinetics after the excessive consumption of alcohol, i.e., 540 ml of 19.5% alcohol (v/v). Fifteen healthy males were included in this randomized, 3 × 3 crossover study. Three combinations were tested: X, normal alcoholic beverage and normal water; Y, oxygenated alcoholic beverage and normal water; Z, oxygenated alcoholic beverage and oxygenated water. Blood alcohol concentrations (BACs) were determined by conversion of breath alcohol concentrations. Four pharmacokinetic parameters (C(max), T(max), K(el), and AUCall) were obtained using non-compartmental analysis and the times to reach 0.05% and 0.03% BAC (T(0.05%) and T(0.03%)) were compared using one-way analysis of variance (ANOVA) and Duncan's post hoc test. With combination Z, the BAC decreased to 0.05% significantly faster (p < 0.05) than with combination X. Analyzing the pharmacokinetic parameters, the mean K(el) was significantly higher for combination Z than for combinations X and Y (p < 0.05), whereas the mean values of C(max), T(max) and AUCall did not differ significantly among the combinations. Dissolved oxygen in drinks accelerates the decrease in BAC after consuming a large amount of alcohol. However, the oxygen dissolved in the alcoholic beverage alone did not have a sufficient effect in this case. We postulate that highly oxygenated water augments the effect of oxygen in the alcoholic beverage in alcohol elimination. Therefore, it is necessary to investigate the supportive effect of ingesting additional oxygenated water after heavy drinking of normal alcoholic beverages. Copyright © 2013 Elsevier Inc. All rights reserved.

A multisyringe flow injection Winkler-based spectrophotometric analyzer for in-line monitoring of dissolved oxygen in seawater.

PubMed

Horstkotte, Burkhard; Alonso, Juan Carlos; Miró, Manuel; Cerdà, Víctor

2010-01-15

An integrated analyzer based on the multisyringe flow injection analysis approach is proposed for the automated determination of dissolved oxygen in seawater. The entire Winkler method including precipitation of manganese(II) hydroxide, fixation of dissolved oxygen, dissolution of the oxidized manganese hydroxide precipitate, and generation of iodine and tri-iodide ion are in-line effected within the flow network. Spectrophotometric quantification of iodine and tri-iodide at the isosbestic wavelength of 466nm renders enhanced method reliability. The calibration function is linear up to 19mgL(-1) dissolved oxygen and an injection frequency of 17 per hour is achieved. The multisyringe system features a highly satisfying signal stability with repeatabilities of 2.2% RSD that make it suitable for continuous determination of dissolved oxygen in seawater. Compared to the manual starch-end-point titrimetric Winkler method and early reported automated systems, concentrations and consumption of reagents and sample are reduced up to hundredfold. The versatility of the multisyringe assembly was exploited in the implementation of an ancillary automatic batch-wise Winkler titrator using a single syringe of the module for accurate titration of the released iodine/tri-iodide with thiosulfate.

Effects of solution chemistry on arsenic(V) removal by low-cost adsorbents.

PubMed

Wang, Yuru; Tsang, Daniel C W

2013-11-01

Natural and anthropogenic arsenic (As) contamination of water sources pose serious health concerns, especially for small communities in rural areas. This study assessed the applicability of three industrial byproducts (coal fly ash, lignite, and green waste compost) as the low-cost adsorbents for As(V) removal under various field-relevant conditions (dissolved oxygen, As(V)/Fe ratio, solution pH, and presence of competing species). The physico-chemical properties of the adsorbents were characterized by XRD, XRF, FT-IR, and NMR analysis. Batch experiments demonstrated that coal fly ash could provide effective As(V) removal (82.1%-95%) because it contained high content of amorphous iron/aluminium hydroxides for As(V) adsorption and dissolvable calcium minerals for calcium arsenate precipitation. However, the addition of lignite and green waste compost was found unfavourable since they hindered the As(V) removal by 10%-42% possibly due to dissolution of organic matter and ternary arsenate-iron-organic matter complexes. On the other hand, higher concentrations of dissolved iron (comparing As(V)/Fe ratios of 1:1 and 1:10) and dissolved oxygen (comparing 0.2 and 6 mg/L) only marginally enhanced the As(V) removal at pH 6 and 8. Thus, addition of dissolved iron, water aeration, or pH adjustment became unnecessary because coal fly ash was able to provide effective As(V) removal under the natural range of geochemical conditions. Moreover, the presence of low levels of background competing (0.8 or 8 mg/L of humic acid, phosphate, and silicate) imposed little influence on As(V) removal, possibly because the high adsorption capacity of coal fly ash was far from exhaustion. These results suggested that coal fly ash was a potentially promising adsorbent that warranted further investigation.

NMR of laser-polarized 129Xe in blood foam

NASA Technical Reports Server (NTRS)

Tseng, C. H.; Peled, S.; Nascimben, L.; Oteiza, E.; Walsworth, R. L.; Jolesz, F. A.

1997-01-01

Laser-polarized 129Xe dissolved in a foam preparation of fresh human blood was investigated. The NMR signal of 129Xe dissolved in blood was enhanced by creating a foam in which the dissolved 129Xe exchanged with a large reservoir of gaseous laser-polarized 129Xe. The dissolved 129Xe T1 in this system was found to be significantly shorter in oxygenated blood than in deoxygenated blood. The T1 of 129Xe dissolved in oxygenated blood foam was found to be approximately 21 (+/-5) s, and in deoxygenated blood foam to be greater than 40 s. To understand the oxygenation trend, T1 measurements were also made on plasma and hemoglobin foam preparations. The measurement technique using a foam gas-liquid exchange interface may also be useful for studying foam coarsening and other liquid physical properties.

Biosynthesis of polyhydroxyalkanaotes by a novel facultatively anaerobic Vibrio sp. under marine conditions.

PubMed

Numata, Keiji; Doi, Yoshiharu

2012-06-01

Marine bacteria have recently attracted attention as potentially useful candidates for the production of practical materials from marine ecosystems, including the oceanic carbon dioxide cycle. The advantages of using marine bacteria for the biosynthesis of poly(hydroxyalkanoate) (PHA), one of the eco-friendly bioplastics, include avoiding contamination with bacteria that lack salt-water resistance, ability to use filtered seawater as a culture medium, and the potential for extracellular production of PHA, all of which would contribute to large-scale industrial production of PHA. A novel marine bacterium, Vibrio sp. strain KN01, was isolated and characterized in PHA productivity using various carbon sources under aerobic and aerobic-anaerobic marine conditions. The PHA contents of all the samples under the aerobic-anaerobic condition, especially when using soybean oil as the sole carbon source, were enhanced by limiting the amount of dissolved oxygen. The PHA accumulated using soybean oil as a sole carbon source under the aerobic-anaerobic condition contained 14% 3-hydroxypropionate (3HP) and 3% 5-hydroxyvalerate (5HV) units in addition to (R)-3-hydroxybutyrate (3HB) units and had a molecular weight of 42 × 10³ g/mol. The present result indicates that the activity of the beta-oxidation pathway under the aerobic-anaerobic condition is reduced due to a reduction in the amount of dissolved oxygen. These findings have potential for use in controlling the biosynthesis of long main-chain PHA by regulating the activity of the beta-oxidation pathway, which also could be regulated by varying the dissolved oxygen concentration.

Water Quality Characteristics of Sembrong Dam Reservoir, Johor, Malaysia

NASA Astrophysics Data System (ADS)

Mohd-Asharuddin, S.; Zayadi, N.; Rasit, W.; Othman, N.

2016-07-01

A study of water quality and heavy metal content in Sembrong Dam water was conducted from April - August 2015. A total of 12 water quality parameters and 6 heavy metals were measured and classified based on the Interim National Water Quality Standard of Malaysia (INWQS). The measured and analyzed parameter variables were divided into three main categories which include physical, chemical and heavy metal contents. Physical and chemical parameter variables were temperature, dissolved oxygen (DO), biochemical oxygen demand (BOD), chemical oxygen demand (COD), total suspended solid (TSS), turbidity, pH, nitrate, phosphate, ammonium, conductivity and salinity. The heavy metals measured were copper (Cu), lead (Pb), aluminium (Al), chromium (Cr), ferum (Fe) and zinc (Zn). According to INWQS, the water salinity, conductivity, BOD, TSS and nitrate level fall under Class I, while the Ph, DO and turbidity lie under Class IIA. Furthermore, values of COD and ammonium were classified under Class III. The result also indicates that the Sembrong Dam water are not polluted with heavy metals since all heavy metal readings recorded were falls far below Class I.

Accumulation of Fe oxyhydroxides in the Peruvian oxygen deficient zone implies non-oxygen dependent Fe oxidation

DOE PAGES

Heller, Maija I.; Lam, Phoebe J.; Moffett, James W.; ...

2017-05-19

Oxygen minimum zones (OMZs) have been proposed to be an important source of dissolved iron (Fe) into the interior ocean. However, previous studies in OMZs have shown a sharp decrease in total dissolved Fe (dFe) and/or dissolved Fe(II) (dFe(II)) concentrations at the shelf-break, despite constant temperature, salinity and continued lack of oxygen across the shelf-break. The loss of both total dFe and dFe(II) suggests a conversion of the dFe to particulate form, but studies that have coupled the reduction-oxidation (redox) speciation of both dissolved and particulate phases have not previously been done. Here in this work, we have measured themore » redox speciation and concentrations of both dissolved and particulate forms of Fe in samples collected during the U.S. GEOTRACES Eastern tropical Pacific Zonal Transect (EPZT) cruise in 2013 (GP16). This complete data set allows us to assess possible mechanisms for loss of dFe. We observed an offshore loss of dFe(II) within the oxygen deficient zone (ODZ), where dissolved oxygen is undetectable, accompanied by an increase in total particulate Fe (pFe). Total pFe concentrations were highest in the upper ODZ. X-ray absorption spectroscopy revealed that the pFe maximum was primarily in the Fe(III) form as Fe(III) oxyhydroxides. The remarkable similarity in the distributions of total particulate iron and nitrite suggests a role for nitrite in the oxidation of dFe(II) to pFe(III). Lastly, we present a conceptual model for the rapid redox cycling of Fe that occurs in ODZs, despite the absence of oxygen.« less

Accumulation of Fe oxyhydroxides in the Peruvian oxygen deficient zone implies non-oxygen dependent Fe oxidation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Heller, Maija I.; Lam, Phoebe J.; Moffett, James W.

Oxygen minimum zones (OMZs) have been proposed to be an important source of dissolved iron (Fe) into the interior ocean. However, previous studies in OMZs have shown a sharp decrease in total dissolved Fe (dFe) and/or dissolved Fe(II) (dFe(II)) concentrations at the shelf-break, despite constant temperature, salinity and continued lack of oxygen across the shelf-break. The loss of both total dFe and dFe(II) suggests a conversion of the dFe to particulate form, but studies that have coupled the reduction-oxidation (redox) speciation of both dissolved and particulate phases have not previously been done. Here in this work, we have measured themore » redox speciation and concentrations of both dissolved and particulate forms of Fe in samples collected during the U.S. GEOTRACES Eastern tropical Pacific Zonal Transect (EPZT) cruise in 2013 (GP16). This complete data set allows us to assess possible mechanisms for loss of dFe. We observed an offshore loss of dFe(II) within the oxygen deficient zone (ODZ), where dissolved oxygen is undetectable, accompanied by an increase in total particulate Fe (pFe). Total pFe concentrations were highest in the upper ODZ. X-ray absorption spectroscopy revealed that the pFe maximum was primarily in the Fe(III) form as Fe(III) oxyhydroxides. The remarkable similarity in the distributions of total particulate iron and nitrite suggests a role for nitrite in the oxidation of dFe(II) to pFe(III). Lastly, we present a conceptual model for the rapid redox cycling of Fe that occurs in ODZs, despite the absence of oxygen.« less

Accumulation of Fe oxyhydroxides in the Peruvian oxygen deficient zone implies non-oxygen dependent Fe oxidation

NASA Astrophysics Data System (ADS)

Heller, Maija I.; Lam, Phoebe J.; Moffett, James W.; Till, Claire P.; Lee, Jong-Mi; Toner, Brandy M.; Marcus, Matthew A.

2017-08-01

Oxygen minimum zones (OMZs) have been proposed to be an important source of dissolved iron (Fe) into the interior ocean. However, previous studies in OMZs have shown a sharp decrease in total dissolved Fe (dFe) and/or dissolved Fe(II) (dFe(II)) concentrations at the shelf-break, despite constant temperature, salinity and continued lack of oxygen across the shelf-break. The loss of both total dFe and dFe(II) suggests a conversion of the dFe to particulate form, but studies that have coupled the reduction-oxidation (redox) speciation of both dissolved and particulate phases have not previously been done. Here we have measured the redox speciation and concentrations of both dissolved and particulate forms of Fe in samples collected during the U.S. GEOTRACES Eastern tropical Pacific Zonal Transect (EPZT) cruise in 2013 (GP16). This complete data set allows us to assess possible mechanisms for loss of dFe. We observed an offshore loss of dFe(II) within the oxygen deficient zone (ODZ), where dissolved oxygen is undetectable, accompanied by an increase in total particulate Fe (pFe). Total pFe concentrations were highest in the upper ODZ. X-ray absorption spectroscopy revealed that the pFe maximum was primarily in the Fe(III) form as Fe(III) oxyhydroxides. The remarkable similarity in the distributions of total particulate iron and nitrite suggests a role for nitrite in the oxidation of dFe(II) to pFe(III). We present a conceptual model for the rapid redox cycling of Fe that occurs in ODZs, despite the absence of oxygen.

Oxygen stress reduces zoospore survival of Phytophthora species in a simulated aquatic system.

PubMed

Kong, Ping; Hong, Chuanxue

2014-05-13

The genus Phytophthora includes a group of agriculturally important pathogens and they are commonly regarded as water molds. They produce motile zoospores that can move via water currents and on their own locomotion in aquatic environments. However, zoosporic response to dissolved oxygen, an important water quality parameter, is not known. Like other water quality parameters, dissolved oxygen concentration in irrigation reservoirs fluctuates dramatically over time. The aim of this study was to determine whether and how zoospore survival may be affected by elevated and low concentrations of dissolved oxygen in water to better understand the aquatic biology of these pathogens in irrigation reservoirs. Zoospores of P. megasperma, P. nicotianae, P. pini and P. tropicalis were assessed for survival in 10% Hoagland's solution at a range of dissolved concentrations from 0.9 to 20.1 mg L(-1) for up to seven exposure times from 0 to 72 h. Zoospore survival was measured by resultant colony counts per ml. Zoospores of these species survived the best in control Hoagland's solution at dissolved oxygen concentrations of 5.3 to 5.6 mg L(-1). Zoospore survival rates decreased with increasing and decreasing concentration of dissolved oxygen, depending upon Phytophthora species and exposure time. Overall, P. megasperma and P. pini are less sensitive than P. nicotianae and P. tropicalis to hyperoxia and hypoxia conditions. Zoospores in the control solution declined over time and this natural decline process was enhanced under hyperoxia and hypoxia conditions. These findings suggest that dramatic fluctuations of dissolved oxygen in irrigation reservoirs contribute to the population decline of Phytophthora species along the water path in the same reservoirs. These findings advanced our understanding of the aquatic ecology of these pathogens in irrigation reservoirs. They also provided a basis for pathogen risk mitigation by prolonging the turnover time of runoff water in recycling irrigation systems via better system designs.

Oxygen stress reduces zoospore survival of Phytophthora species in a simulated aquatic system

PubMed Central

2014-01-01

Background The genus Phytophthora includes a group of agriculturally important pathogens and they are commonly regarded as water molds. They produce motile zoospores that can move via water currents and on their own locomotion in aquatic environments. However, zoosporic response to dissolved oxygen, an important water quality parameter, is not known. Like other water quality parameters, dissolved oxygen concentration in irrigation reservoirs fluctuates dramatically over time. The aim of this study was to determine whether and how zoospore survival may be affected by elevated and low concentrations of dissolved oxygen in water to better understand the aquatic biology of these pathogens in irrigation reservoirs. Results Zoospores of P. megasperma, P. nicotianae, P. pini and P. tropicalis were assessed for survival in 10% Hoagland’s solution at a range of dissolved concentrations from 0.9 to 20.1 mg L-1 for up to seven exposure times from 0 to 72 h. Zoospore survival was measured by resultant colony counts per ml. Zoospores of these species survived the best in control Hoagland’s solution at dissolved oxygen concentrations of 5.3 to 5.6 mg L-1. Zoospore survival rates decreased with increasing and decreasing concentration of dissolved oxygen, depending upon Phytophthora species and exposure time. Overall, P. megasperma and P. pini are less sensitive than P. nicotianae and P. tropicalis to hyperoxia and hypoxia conditions. Conclusion Zoospores in the control solution declined over time and this natural decline process was enhanced under hyperoxia and hypoxia conditions. These findings suggest that dramatic fluctuations of dissolved oxygen in irrigation reservoirs contribute to the population decline of Phytophthora species along the water path in the same reservoirs. These findings advanced our understanding of the aquatic ecology of these pathogens in irrigation reservoirs. They also provided a basis for pathogen risk mitigation by prolonging the turnover time of runoff water in recycling irrigation systems via better system designs. PMID:24885900

[Photodegradation of naproxen in aqueous systems by UV irradiation: mechanism and toxicity of photolysis products].

PubMed

Ma, Du-juan; Liu, Guo-guang; Lü, Wen-ying; Yao, Kun; Zhou, Li-hua; Xie, Cheng-ping

2013-05-01

This paper studies the degradation mechanism, the reaction kinetics and the toxicity of photolysis products of naproxen in waters under UV irradiation (120 W mercury lamp) by quenching experiments of reactive oxygen species (ROS), oxygen concentration experiment and toxicity evaluation using Vibrio fischeri bacteria. The results demonstrated that NPX could be degraded effectively by UV irradiation and the photolysis pathways was the sum of the degradation by direct photolysis and self-sensitization via ROS, and the contribution rates of self-sensitized photodegradation were 0.1%, 80.2%, 35.7% via *OH, (1)O2, O2*-, respectively. The effect of oxygen concentration illustrated that dissolved oxygen had an inhibitory effect on the direct photodegradation of NPX, and the higher the oxygen content, the more obvious the inhibitory effect. The toxicity evaluation illustrated the formation of some intermediate products that were more toxic than NPX during the photodegradation of NPX. The process of NPX degradation in all cases could be fitted by the pseudo first-order kinetics model.

Water-quality assessment of the Porter County Watershed, Kankakee River basin, Porter County, Indiana

USGS Publications Warehouse

Bobo, Linda L.; Renn, Danny E.

1980-01-01

Water type in the 241-square mile Porter County watershed in Indiana, was calcium bicarbonate or mixed calcium bicarbonate and calcium sulfate. Concentrations of dissolved chemical constituents in surface water and contents of chlorinated hydrocarbons in streambed samples in the watershed were generally less than water-quality alert limits set by the U.S. Environmental Protection Agency, except in Crooked Creek. During sampling, this stream was affected by sewage, chlorinated hydrocarbons, and two chemical spills. Ranges of on-site field measurements were: specific conductance, from 102 to 1,060 micromhos per centimeter at 25 Celcius; water temperature, from 7.0 to 31.8 Celsius; pH, from 6.8 to 8.9; dissolved oxygen, from 2.5 to 14.9 milligrams per liter and from 27 to 148% saturation; and instantaneous discharge from 0 to 101 cubic feet per second. Concentrations of most dissolved-inorganic constituents (heavy metals and major ions) and dissolved solids did not vary significantly from one sampling period to the next at each site. Dissolved constituents whose concentrations varied significantly were iron, manganese, organic carbon, ammonia, nitrate plus nitrite, organic nitrogen, Kjeldahl nitrogen, and phosphorus. Concentrations of dissolved manganese, organic carbon, dissolved nitrite plus nitrate, and suspended sediment varied seasonally at most sites. Populations and identification of bacteria, phytoplankton, periphyton, and benthic invertebrates indicate a well-balanced environment at most sites, except in Crooked Creek.

Effects of bottom water dissolved oxygen variability on copper and lead fractionation in the sediments across the oxygen minimum zone, western continental margin of India.

PubMed

Chakraborty, Parthasarathi; Chakraborty, Sucharita; Jayachandran, Saranya; Madan, Ritu; Sarkar, Arindam; Linsy, P; Nath, B Nagender

2016-10-01

This study describes the effect of varying bottom-water oxygen concentration on geochemical fractionation (operational speciation) of Cu and Pb in the underneath sediments across the oxygen minimum zone (Arabian Sea) in the west coast of India. Both, Cu and Pb were redistributed among the different binding phases of the sediments with changing dissolved oxygen level (from oxic to hypoxic and close to suboxic) in the bottom water. The average lability of Cu-sediment complexes gradually decreased (i.e., stability increased) with the decreasing dissolved oxygen concentrations of the bottom water. Decreasing bottom-water oxygen concentration increased Cu association with sedimentary organic matter. However, Pb association with Fe/Mn-oxyhydroxide phases in the sediments gradually decreased with the decreasing dissolved oxygen concentration of the overlying bottom water (due to dissolution of Fe/Mn oxyhydroxide phase). The lability of Pb-sediment complexes increased with the decreasing bottom-water oxygen concentration. This study suggests that bottom-water oxygen concentration is one of the key factors governing stability and lability of Cu and Pb complexes in the underneath sediment. Sedimentary organic matter and Fe/Mn oxyhydroxide binding phases were the major hosting phases for Cu and Pb respectively in the study area. Increasing lability of Pb-complexes in bottom sediments may lead to positive benthic fluxes of Pb at low oxygen environment. Copyright © 2016 Elsevier B.V. All rights reserved.

Dissolved oxygen sensing using organometallic dyes deposited within a microfluidic environment

NASA Astrophysics Data System (ADS)

Chen, Q. L.; Ho, H. P.; Jin, L.; Chu, B. W.-K.; Li, M. J.; Yam, V. W.-W.

2008-02-01

This work primarily aims to integrate dissolved oxygen sensing capability with a microfluidic platform containing arrays of micro bio-reactors or bio-activity indicators. The measurement of oxygen concentration is of significance for a variety of bio-related applications such as cell culture and gene expression. Optical oxygen sensors based on luminescence quenching are gaining much interest in light of their low power consumption, quick response and high analyte sensitivity in comparison to similar oxygen sensing devices. In our microfluidic oxygen sensor device, a thin layer of oxygen-sensitive luminescent organometallic dye is covalently bonded to a glass slide. Micro flow channels are formed on the glass slide using patterned PDMS (Polydimethylsiloxane). Dissolved oxygen sensing is then performed by directing an optical excitation probe beam to the area of interest within the microfluidic channel. The covalent bonding approach for sensor layer formation offers many distinct advantages over the physical entrapment method including minimizing dye leaching, ensuring good stability and fabrication simplicity. Experimental results confirm the feasibility of the device.

Handbook for Evaluating Ecological Effects of Pollution at DARCOM Installations. Volume 5. Aquatic Surveys,

DTIC Science & Technology

1980-05-01

occur in areas of high current and pools in areas of low current. The habitats of greatest invertebrate animal production in streams are riffles. They...feeding and spawning ground for trout, smallmouth bass, and other fish. Dissolved oxygen content is high and primary production (plant material) is...stream forms. In pools, primary production is generally higher than in riffles if siltation and 1-3 organic pollution are not high enough to cause

Chapter A7. Section 7.0. Five-Day Biochemical Oxygen Demand

USGS Publications Warehouse

Delzer, Gregory C.; McKenzie, Stuart W.

1999-01-01

The presence of a sufficient concentration of dissolved oxygen is critical to maintaining the aquatic life and aesthetic quality of streams and lakes. Determinng how organic matter affects the concentration of dissolved oxygen (DO) in a stream or lake is integral to water-quality management. The decay of organic matter in water is measured as biochemical or chemical oxygen demand. This report describes the field protocols used by U.S. Geological Survey (USGS) personnel to determine the five-day test for biochemical oxygen demand.

Method of determining the extent to which a nickel structure has been attached by a fluorine-containing gas

DOEpatents

Brusie, James P.

2004-07-13

The method of determining the extent to which a nickel structure has been attacked by a halogen containing gas to which it has been exposed which comprises preparing a quantity of water substantially free from dissolved oxygen, passing ammonia gas through a cuprammonium solution to produce ammonia substantially free from oxygen, dissolving said oxygen-free ammonia in said water to produce a saturated aqueous ammonia solution free from uncombined oxygen, treating at least a portion of said nickel structure of predetermined weight with said solution to dissolve nickel compounds from the surface of said structure without dissolving an appreciable amount of said nickel and analyzing the resulting solution to determine the quantity of said nickel compounds that was associated with said said portion of said structure to determine the proportion of combined nickel in said nickel structure.

Amphiphilic Fluorinated Polymer Nanoparticle Film Formation and Dissolved Oxygen Sensing Application

NASA Astrophysics Data System (ADS)

Gao, Yu; Zhu, Huie; Yamamoto, Shunsuke; Miyashita, Tokuji; Mitsuishi, Masaya

2016-04-01

Fluorinated polymer nanoparticle films were prepared by dissolving amphiphilic fluorinated polymer, poly (N-1H, 1H-pentadecafluorooctylmethacrylamide) (pC7F15MAA) in two miscible solvents (AK-225 and acetic acid). A superhydrophobic and porous film was obtained by dropcasting the solution on substrates. With higher ratios of AK-225 to acetic acid, pC7F15MAA was densified around acetic acid droplets, leading to the formation of pC7F15MAA nanoparticles. The condition of the nanoparticle film preparation was investigated by varying the mixing ratio or total concentration. A highly sensitive dissolved oxygen sensor system was successfully prepared utilizing a smart surface of superhydrophobic and porous pC7F15MAA nanoparticle film. The sensitivity showed I0/I40 = 126 in the range of dissolved oxygen concentration of 0 ~ 40 mg L-1. The oxygen sensitivity was compared with that of previous reports.

A Quantitative Evaluation of Dissolved Oxygen Instrumentation

NASA Technical Reports Server (NTRS)

Pijanowski, Barbara S.

1971-01-01

The implications of the presence of dissolved oxygen in water are discussed in terms of its deleterious or beneficial effects, depending on the functional consequences to those affected, e.g., the industrialist, the oceanographer, and the ecologist. The paper is devoted primarily to an examination of the performance of five commercially available dissolved oxygen meters. The design of each is briefly reviewed and ease or difficulty of use in the field described. Specifically, the evaluation program treated a number of parameters and user considerations including an initial check and trial calibration for each instrument and a discussion of the measurement methodology employed. Detailed test results are given relating to the effects of primary power variation, water-flow sensitivity, response time, relative accuracy of dissolved-oxygen readout, temperature accuracy (for those instruments which included this feature), error and repeatability, stability, pressure and other environmental effects, and test results obtained in the field. Overall instrument performance is summarized comparatively by chart.

Productivity Estimation of Hypersaline Microbial Mat Communities - Diurnal Cycles of Dissolved Oxygen

NASA Astrophysics Data System (ADS)

Less, G.; Cohen, Y.; Luz, B.; Lazar, B.

2002-05-01

Hypersaline microbial mat communities (MMC) are the modern equivalents of the Archean stromatolities, the first photosynthetic organisms on Earth. An estimate of their oxygen production rate is important to the understanding of oxygen evolution on Earth ca. 2 b.y.b.p. Here we use the diurnal cycle of dissolved oxygen, O2/Ar ratio and the isotopic composition of dissolved oxygen to calculate net and gross primary productivity of MMC growing in a large scale (80 m2) experimental pan. The pan is inoculated with MMC taken from the Solar Lake, Sinai, Egypt and filled with 90\\permil evaporated Red Sea water brine up to a depth of ca. 0.25 m. It is equipped with computerized flow through system that is programmed to pump pan water at selected time intervals into a sampling cell fitted with dissolved oxygen, pH, conductivity and temperature sensors connected to a datalogger. Manual brine samples were taken for calibrating the sensors, mass spectrometric analyses and for measurements of additional relevant parameters. Dissolved oxygen concentrations fluctuate during the diurnal cycle being highly supersaturated except for the end of the night. The O2 curve varies seasonally and has a typical "shark fin" shape due to the MMC metabolic response to the shape of the diurnal light curve. The dissolved oxygen data were fitted to a smooth curve that its time derivative (dO2 /dt) is defined as: Z dO2 /dt=GP-R-k(O2(meas)- O2(sat)) where z is the depth (m); GP and R are the MMC gross production and respiration (mol m-2 d-1), respectively; k is the gas exchange coefficient (m d-1); O2(meas) and O2(sat) (mol L-1) are the measured and equilibrium dissolved oxygen concentrations, respectively. The high resolution sampling of the automated system produces O2 curves that enable the calculation of smooth and reliable time derivatives. The calculations yield net production values that vary between 1,000 10-6 to -100 10-6 mol O2 m-2 h-1 and day respiration rates between 60 10-6 to 30 10-6 mol O2 m-2 h-1 in summer and winter, respectively. Independent estimate of the gross productivity and respiration is provided by the oxygen isotopic measurements.

Continued studies of acid rain and its effects on the Baton Rouge area

DOE Office of Scientific and Technical Information (OSTI.GOV)

Robinson, J.W.; Ghane, H.

1983-01-01

The acidity of rain water was measured in the Baton Rouge, Louisiana area from June 1981 to September 1982. Coordinated measurements were taken of the dissolved oxygen concentration in two local lakes before and after each rainfall. About 50% of the rainfall observed was quite acidic, with about 25% of the rain having a pH of 4 or less. Rain was more acidic during warm summers than in the winter weather. Rainfall during 1982 was, on a month to month comparison, more acidic than in 1981. Attempts were also made to discover any possible correlation of pH values with windmore » direction. The acidity of each of the two lakes increased over the time of the study. The dissolved oxygen content in each lake increased after periods of rain, probably due to a high concentration of oxygen in the rainwater. The buffering capacities of the lakes was measurable. However, it is noted that the larger lake was undergoing dredging at the time of the study and showed considerably less buffer capacity than the smaller lake. The smaller lake was far more affected by surface drainage and thus should have been more influenced by the acid rain. 7 references, 7 figures, 1 table.« less

Stimulating hydrogenotrophic denitrification in simulated groundwater containing high dissolved oxygen and nitrate concentrations.

PubMed

Schnobrich, Matthew R; Chaplin, Brian P; Semmens, Michael J; Novak, Paige J

2007-05-01

In agricultural areas, nitrate (NO3-) is a common groundwater pollutant as a result of extensive fertilizer application. At elevated concentrations, NO3- consumption causes methemoglobinemia in infants and has been linked to several cancers; therefore, its removal from groundwater is important. The addition of hydrogen gas (H2) via gas-permeable membranes has been shown to stimulate denitrification in a laboratory-scale reactor. This research, using large columns packed with aquifer material to which a simulated groundwater was fed, was conducted to further identify the conditions required for the use of membrane-delivered H2 in situ. In this study, we show that this novel technology was capable of treating highly contaminated (25 mg/L NO3- -N) and oxygenated (5.5mg/L dissolved oxygen) water, but that nutrient addition and gas pressure adjustment was required. Complete NO3- reduction was possible without the accumulation of either NO2- or N2O when the H2 lumen pressure was increased to 17 psi and phosphate was added to the groundwater. The total organic carbon content of the effluent, 110 cm downgradient of H2 addition, did not increase. The results from these experiments demonstrate that this technology can be optimized to provide effective NO3- removal in even challenging field applications.

Cytotoxicity and genotoxicity evaluation of urban surface waters using freshwater luminescent bacteria Vibrio-qinghaiensis sp.-Q67 and Vicia faba root tip.

PubMed

Ma, Xiaoyan; Wang, Xiaochang; Liu, Yongjun

2012-01-01

The freshwater luminescent bacteria Vibrio-qinghaiensis sp.-Q67 test and the Vicia faba root tip test associated with solid-phase extraction were applied for cytotoxicity and genotoxicity assessment of organic substances in three rivers, two lakes and effluent flows from two wastewater treatment plants (WWTPs) in Xi'an, China. Although the most seriously polluted river with high chemical oxygen demand (COD) and total organic carbon (TOC) showed high cytotoxicity (expressed as TII50, the toxicity impact index) and genotoxicity (expressed as RMCN, the relative frequency of micronucleus), no correlative relation was found between the ecotoxicity and organic content of the water samples. However, there was a linear correlative relation between TII50 and RMCN for most water samples except that from the Zaohe River, which receives discharge from WWTP and untreated industrial wastewaters. The ecotoxicity of the organic toxicants in the Chanhe River and Zaohe River indicated that cytotoxic and genotoxic effects were related to the pollutant source. The TII50 and RMCN were also found to correlate roughly to the dissolved oxygen concentration of the water. Sufficient dissolved oxygen in surface water is thus proved to be an indicator of a healthy water environmental condition.

Maps showing predicted probabilities for selected dissolved oxygen and dissolved manganese threshold events in depth zones used by the domestic and public drinking water supply wells, Central Valley, California

USGS Publications Warehouse

Rosecrans, Celia Z.; Nolan, Bernard T.; Gronberg, JoAnn M.

2018-01-31

The purpose of the prediction grids for selected redox constituents—dissolved oxygen and dissolved manganese—are intended to provide an understanding of groundwater-quality conditions at the domestic and public-supply drinking water depths. The chemical quality of groundwater and the fate of many contaminants is influenced by redox processes in all aquifers, and understanding the redox conditions horizontally and vertically is critical in evaluating groundwater quality. The redox condition of groundwater—whether oxic (oxygen present) or anoxic (oxygen absent)—strongly influences the oxidation state of a chemical in groundwater. The anoxic dissolved oxygen thresholds of <0.5 milligram per liter (mg/L), <1.0 mg/L, and <2.0 mg/L were selected to apply broadly to regional groundwater-quality investigations. Although the presence of dissolved manganese in groundwater indicates strongly reducing (anoxic) groundwater conditions, it is also considered a “nuisance” constituent in drinking water, making drinking water undesirable with respect to taste, staining, or scaling. Three dissolved manganese thresholds, <50 micrograms per liter (µg/L), <150 µg/L, and <300 µg/L, were selected to create predicted probabilities of exceedances in depth zones used by domestic and public-supply water wells. The 50 µg/L event threshold represents the secondary maximum contaminant level (SMCL) benchmark for manganese (U.S. Environmental Protection Agency, 2017; California Division of Drinking Water, 2014), whereas the 300 µg/L event threshold represents the U.S. Geological Survey (USGS) health-based screening level (HBSL) benchmark, used to put measured concentrations of drinking-water contaminants into a human-health context (Toccalino and others, 2014). The 150 µg/L event threshold represents one-half the USGS HBSL. The resultant dissolved oxygen and dissolved manganese prediction grids may be of interest to water-resource managers, water-quality researchers, and groundwater modelers concerned with the occurrence of natural and anthropogenic contaminants related to anoxic conditions. Prediction grids for selected redox constituents and thresholds were created by the USGS National Water-Quality Assessment (NAWQA) modeling and mapping team.

Measurement in a marine environment using low cost sensors of temperature and dissolved oxygen

USGS Publications Warehouse

Godshall, F.A.; Cory, R.L.; Phinney, D.E.

1974-01-01

Continuous records of physical parameters of the marine environment are difficult as well as expensive to obtain. This paper describes preliminary results of an investigative program with the purpose of developing low cost time integrating measurement and averaging devices for water temperature and dissolved oxygen. Measurements were made in an estuarine area of the Chesapeake Bay over two week periods. With chemical thermometers average water temperature for the two week period was found to be equal to average water temperature measured with thermocouples plus or minus 1.0 C. The slow diffusion of oxygen through the semipermiable sides of plastic bottles permitted the use of water filled bottles to obtain averaged oxygen measurements. Oxygen measurements for two week averaging times using 500 ml polyethylene bottles were found to vary from conventionally measured and averaged dissolved oxygen by about 1.8 mg/l. ?? 1974 Estuarine Research Federation.

Effects of dissolved oxygen concentration on photosynthetic bacteria wastewater treatment: Pollutants removal, cell growth and pigments production.

PubMed

Meng, Fan; Yang, Anqi; Zhang, Guangming; Wang, Hangyao

2017-10-01

Dissolved oxygen (DO) is an important parameter in photosynthetic bacteria (PSB) wastewater treatment. This study set different DO levels and detected the pollutants removal, PSB growth and pigments production. Results showed that DO significantly influenced the performances of PSB wastewater treatment process. The highest COD (93%) and NH 3 -N removal (83%) was achieved under DO of 4-8mg/L, but DO of 2-4mg/L was recommended considering the aeration cost. PSB biomass reached 1645mg/L under DO of 4-8mg/L with satisfying co-enzyme Q10 content. The biomass yield was relatively stable at all DO levels. For bacteriochlorophyll and carotenoids, DO>1mg/L could satisfy their production. On the other hand, DO<0.5mg/L led to the highest dehydrogenase activity. According to the different purposes, the optimal treatment time was different. The most pigments production occurred at 24h; biomass reached peak at 48h; and the optimal time for pollutants removal was 72h. Copyright © 2017 Elsevier Ltd. All rights reserved.

Seasonal variations in physico-chemical characteristics of Tuticorin coastal waters, southeast coast of India

NASA Astrophysics Data System (ADS)

Balakrishnan, S.; Chelladurai, G.; Mohanraj, J.; Poongodi, J.

2017-07-01

Physico-chemical parameters were determined along the Vellapatti, Tharuvaikulam and Threspuram coastal waters, southeast coast of India. All the physico-chemical parameters such as sea surface temperature, salinity, pH, total alkalinity, total suspended solids, dissolved oxygen and nutrients like nitrate, nitrite, inorganic phosphate and reactive silicate were studied for a period of 12 months (June 2014-May 2015). Sea surface temperature varied from 26.4 to 29.7 °C. Salinity varied from 26.1 and 36.2 ‰, hydrogen ion concentration ranged between 8.0 and 8.5. Variation in dissolved oxygen content was from 4.125 to 4.963 mg l-1. Total alkalinity ranged from 64 to 99 mg/l. Total suspended solids ranged from 24 to 97 mg/l. Concentrations of nutrients, viz. nitrates (2.047-4.007 μM/l), nitrites (0.215-0.840 μM/l), phosphates (0.167-0.904 µM/l), total phosphorus (1.039-3.479 μM/l), reactive silicates (3.737-8.876 μM/l) ammonia (0.078-0.526 μM/l) and also varied independently.

Solubility of oxygen in liquid Fe at high pressure and consequences for the early differentiation of Earth and Mars

NASA Astrophysics Data System (ADS)

Rubie, D. C.; Gessmann, C. K.; Frost, D. J.

2003-04-01

Knowledge of the solubility of oxygen in liquid iron enables the partitioning of oxygen between metal and silicates and the oxidation state of residual silicates to be constrained during core formation in planetary bodies. We have determined oxygen solubility experimentally at 5--23 GPa, 2100--2700 K and oxygen fugacities 1--4 log units below the iron-wüstite buffer in samples of liquid Ni-Fe alloy contained in magnesiowüstite capsules using a multianvil apparatus. Results show that oxygen solubility increases with increasing temperature but decreases slightly with increasing pressure over the range of experimental conditions, at constant oxygen fugacity. Using an extrapolation of the results to higher pressures and temperatures, we have modeled the geochemical consequences of metal-silicate separation in magma oceans in order to explain the contrasting FeO contents of the mantles of Earth and Mars. We assume that both Earth and Mars accreted originally from material with a chondritic composition; because the initial oxidation state is uncertain, we vary this parameter by defining the initial oxygen content. Two metal-silicate fractionation models are considered: (1) Metal and silicate are allowed to equilibrate at fictive conditions that approximate the pressure and temperature at the base of a magma ocean. (2) The effect of settling Fe droplets in a magma ocean is determined using a simple polybaric metal-silicate fractionation model. We assume that the temperature at the base of a magma ocean is close to the peridotite liquidus. In the case of Earth, high temperatures in a magma ocean with a depth >1200 km would have resulted in significant quantities of oxygen dissolving in the liquid metal with the consequent extraction of FeO from the residual silicate. In contrast, on Mars, even if the magma ocean extended to the depth of the current core-mantle boundary, temperatures would not have been sufficiently high for oxygen solubility in liquid metal to be significant. The results show that Earth and Mars could have accreted from similar material, with an initial FeO content around 18 wt%. On Earth, oxygen was extracted from silicates by the segregating metal during core formation, leaving the mantle with its present FeO content of ˜8 wt%. On Mars, in contrast, the segregating metal extracted little or no oxygen and left the FeO content unaltered at ˜18 wt%. A consequence of this model is that oxygen should be an important light element in the Earth's core but not in the Martian core.

An experimental study of ^{{{{Fe}}^{2 + } {-}{{Mg}}}} K_{{D}} between orthopyroxene and rhyolite: a strong dependence on H2O in the melt

NASA Astrophysics Data System (ADS)

Waters, Laura E.; Lange, Rebecca A.

2017-06-01

The effect of temperature, pressure, and dissolved H2O in the melt on the Fe2+-Mg exchange coefficient between orthopyroxene and rhyolite melt was investigated with a series of H2O fluid-saturated phase-equilibrium experiments. Experiments were conducted in a rapid-quench cold-seal pressure vessel over a temperature and pressure range of 785-850 °C and 80-185 MPa, respectively. Oxygen fugacity was buffered with the solid Ni-NiO assemblage in a double-capsule assembly. These experiments, when combined with H2O-undersaturated experiments in the literature, show that ^{{{{Fe}}^{2 + } {-}{{Mg}}}} K_{{D}} between orthopyroxene and rhyolite liquid increases strongly (from 0.23 to 0.54) as a function of dissolved water in the melt (from 2.7 to 5.6 wt%). There is no detectable effect of temperature or pressure over an interval of 65 °C and 100 MPa, respectively, on the Fe2+-Mg exchange coefficient values. The data show that Fe-rich orthopyroxene is favored at high water contents, whereas Mg-rich orthopyroxene crystallizes at low water contents. It is proposed that the effect of dissolved water in the melt on the composition of orthopyroxene is analogous to its effect on the composition of plagioclase. In the latter case, dissolved hydroxyl groups preferentially complex with Na+ relative to Ca2+, which reduces the activity of the albite component, leading to a more anorthite-rich (calcic) plagioclase. Similarly, it is proposed that dissolved hydroxyl groups preferentially complex with Mg2+ relative to Fe2+, thus lowering the activity of the enstatite component, leading to a more Fe-rich orthopyroxene at high water contents in the melt. The experimental results presented in this study show that reversely zoned pyroxene (i.e., Mg-rich rims) in silicic magmas may be a result of H2O degassing and not necessarily the result of mixing with a more mafic magma.

Characterization of nano-bubbles as an oxygen carrier for in-situ bioremediation of organic pollutants in the subsurface

NASA Astrophysics Data System (ADS)

KIM, E.; Jung, J.; Kang, S.; Choi, Y.

2016-12-01

In-situ bioremediation using bubbles as an oxygen carrier has shown its applicability for aerobic biodegradation of organic pollutants in the subsurface. By recent progresses, generation of nano-sized bubbles is possible, which have enhanced oxygen transfer efficiencies due to their high interfacial area and stability. We are developing an in-situ bioremediation technique using nano-bubbles as an oxygen carrier. In this study, nano-bubbles were characterized for their size and oxygen supply capacity. Nano-bubbles were generated with pure oxygen and pure helium gas. The stable nano-bubbles suspended in water were sonicated to induce the bubbles to coalesce, making them to rise and be released out of the water. By removing the bubbles, the water volume was decreased by 0.006%. The gas released from the bubble suspension was collected to measure the amount of gas in the nano-bubbles. For sparingly soluble helium gas 17.9 mL/L was released from the bubble suspension, while for oxygen 46.2 mL/L was collected. For the oxygen nano-bubble suspension, it is likely that the release of dissolved oxygen (DO) contributed to the collected gas volume. After removing the oxygen nano-bubbles, 36.0 mg/L of DO was still present in water. Altogether, the oxygen nano-bubble suspension was estimated to have 66.2 mg/L of oxygen in a dissolved form and 25.6 mg/L as nano-bubbles. A high DO level in the water was possible because of their large Laplace pressure difference across the fluid interface. Applying Young-Laplace equation and ideal gas law, the bubble diameter was estimated to be approximately 10 nm, having an internal pressure of 323 atm. Considering the saturation DO of 8.26 mg/L for water in equilibrium with the atmosphere, the total oxygen content of 91.8 mg/L in the nano-bubble suspension suggests its great potential as an oxygen carrier. Studies are underway to verify the enhanced aerobic biodegradation of organic pollutants in soils by injecting nano-bubble suspensions.

Aquifer geochemistry and effects of pumping on ground-water quality at the Green Belt Parkway Well Field, Holbrook, Long Island, New York

USGS Publications Warehouse

Brown, Craig J.; Colabufo, Steven; Coates, John D.

2002-01-01

Geochemistry, microbiology, and water quality of the Magothy aquifer at a new supply well in Holbrook were studied to help identify factors that contribute to iron-related biofouling of public-supply wells. The organic carbon content of borehole sediments from the screen zone, and the dominant terminal electron-accepting processes (TEAPs), varied by depth. TEAP assays of core sediments indicated that iron reduction, sulfate reduction, and undetermined (possibly oxic) reactions and microbial activity are correlated with organic carbon (lignite) content. The quality of water from this well, therefore, reflects the wide range of aquifer microenvironments at this site.High concentrations of dissolved iron (3.6 to 6.4 micromoles per liter) in water samples from this well indicate that some water is derived from Fe(III)-reducing sediments within the aquifer, but traces of dissolved oxygen indicate inflow of shallow, oxygenated water from shallow units that overlie the local confining units. Water-quality monitoring before and during a 2-day pumping test indicates that continuous pumping from the Magothy aquifer at this site can induce downward flow of shallow, oxygenated water despite the locally confined conditions. Average concentrations of dissolved oxygen are high (5.2 milligrams per liter, or mg/L) in the overlying upper glacial aquifer and at the top of the Magothy aquifer (4.3 mg/L), and low ( < 0.1 mg/L) in the deeper, anaerobic part of the Magothy; average concentrations of phosphate are high (0.4 mg/L) in the upper glacial aquifer and lower (0.008 mg/L) at the top of the Magothy aquifer and in the deeper part of the Magothy (0.013 mg/L). Concentrations of both constituents increased during the 2 days of pumping. The δ34S of sulfate in shallow ground water from observation wells (3.8 to 6.4 per mil) was much heavier than that in the supplywell water (-0.1 per mil) and was used to help identify sources of water entering the supply well. The δ34S of sulfate in a deep observation well adjacent to the supply well increased from 2.4 per mil before pumping to 3.3 per mil after pumping; this confirms that the pumping induced downward migration of water. The lighter δ34S value in the pumped water than in the adjacent observation well probably indicates FeS2 oxidation (which releases light δ34S in adjacent sediments) by the downward flow of oxygenated water.

Microhardness and lattice parameter calibrations of the oxygen solid solutions of unalloyed alpha-titanium and Ti-6Al-2Sn-4Zr-2Mo

NASA Technical Reports Server (NTRS)

Wiedemann, K. E.; Shenoy, R. N.; Unnam, J.

1987-01-01

Standards were prepared for calibrating microanalyses of dissolved oxygen in unalloyed alpha-Ti and Ti-6Al-2Sn-4Zr-2Mo. Foils of both of these materials were homogenized for 120 hours in vacuum at 871 C following short exposures to the ambient atmosphere at 854 C that had partially oxidized the foils. The variation of Knoop microhardness with oxygen content was calibrated for both materials using 15-g and 5-g indentor loads. The unit-cell lattice parameters were calibrated for the unalloyed alpha-Ti. Example analyses demonstrate the usefulness of these calibrations and support an explanation of an anomaly in the lattice parameter variation. The results of the calibrations have been tabulated and summarized using predictive equations.

Determination of oxygen vacancy limit in Mn substituted yttria stabilized zirconia

NASA Astrophysics Data System (ADS)

Stepień, Joanna; Sikora, Marcin; Kapusta, Czesław; Pomykalska, Daria; Bućko, Mirosław M.

2018-05-01

A series of Mnx(Y0.148Zr0.852)1-xO2-δ ceramics was systematically studied by means of X-ray absorption spectroscopy (XAS) and X-ray emission spectroscopy (XES) and DC magnetic susceptibility. The XAS and XES results show the changes in manganese oxidation state and a gradual evolution of the local atomic environment around Mn ions upon increasing dopant contents, which is due to structural relaxation caused by the growing amount of oxygen vacancies. Magnetic susceptibility measurements reveal that Mn3O4 precipitates are formed for x ≥ 0.1 and enable independent determination of the actual quantity of Mn ions dissolved in Yttria Stabilized Zirconia (YSZ) solid solution. We show that the amount of oxygen vacancies generated by manganese doping into YSZ is limited to ˜0.17 per formula unit.

Estuarine studies in upper Grays Harbor, Washington

USGS Publications Warehouse

Beverage, Joseph P.; Swecker, Milton N.

1969-01-01

Improved management of the water resources of Grays Harbor, Wash., requires more data on the water quality of the harbor and a better understanding of the influences of industrial and domestic wastes on the local fisheries resources. To provide a more comprehensive understanding of these influences, the U.S. Geological Survey joined other agencies in a cooperative study of Grays Harbor. This report summarizes the Survey's study of circulation patterns, description of water-quality conditions, and characterization of bottom material in the upper harbor. Salt water was found to intrude at least as far as Montesano, 28.4 nautical miles from the mouth of the harbor. Longitudinal salinity distributions were used to compute dispersion (diffusivity) coefficients ranging from 842 to 3,520 square feet per second. These values were corroborated by half-tidal-cycle dye studies. The waters of the harbor were found to be well mixed after extended periods of low fresh-water flow but stratified at high flows. Salinity data were used lo define the cumulative 'mean age' of the harbor water, which may be used to approximate a mean 'flushing time.' Velocity-time curves for the upper harbor are distorted from simple harmonic functions owing to channel geometry and frictional effects. Surface and bottom velocity data were used to estimate net tidal 'separation' distance, neglecting vertical mixing. Net separation distances between top and bottom water ranged from 1.65 nautical miles when fresh-water inflow was 610 cubic feet per second to 13.4 miles when inflow was 15,900 cubic feet per second. The cumulative mean age from integration of the fresh-water velocity equation was about twice that obtained from the salinity distribution. Excursion distances obtained with dye over half-tidal cycles exceeded those estimated from longitudinal salinity distributions and those obtained by earlier investigators who used floats. Net tidal excursions were as much as twice those obtained with floats. The carbon content of bottom materials was related to channel fine material: C= 0.315+0.0238 F where C is in percent by dry weight, and F is percent by weight finer than 0.062 millimeter. Carbon content was low upstream and downstream of the upper harbor area, and high in the Cow Point-Rennie Island reach. The high-carbon-content reach coincides with the general area of a dissolved-oxygen sag. The logarithm of the fresh-water discharge gave a high degree of correlation with daily maximum specific conductance at Cosmopolis. The regression equation is: Kc max---- 76.4-- 17.7 logl0 Qf where Kc max is in millimhos at 25 ? Celsius (centigrade), and Qf is the estimated daily fresh-water discharge, in cubic feet per second. Dissolved oxygen is the most critical water-quality parameter in Grays Harbor. At Cosmopolis, the daily minimum dissolved oxygen content, DOc min, correlated well with discharge and tidal range, delta H. The regression equation relating the variables is: DOc min---- 6.03 + 0.00096 Qf - 0.291 delta H in which DOc min is in milligrams per liter and delta H is in feet. The upper harbor was found to contain 250 million cubic feet less water than average during the critical low-flow period, on the basis of the frequency distribution of predicted tides. About 78,000 pounds of dissolved oxygen is thus unavailable for oxidation of waste during summer.

The effect of diet, temperature and intermittent low oxygen on the metabolism of rainbow trout.

PubMed

Stiller, Kevin T; Vanselow, Klaus H; Moran, Damian; Riesen, Guido; Koppe, Wolfgang; Dietz, Carsten; Schulz, Carsten

2017-03-01

An automated respirometer system was used to measure VO2, protein catabolism as ammonia quotient and the energy budget to evaluate whether the crude protein content of a standard protein (SP) diet (42·5 %) or a high-protein (HP) diet (49·5 %) influences metabolism in rainbow trout under challenging intermittent, low dissolved oxygen concentrations. In total, three temperature phases (12, 16, 20°C) were tested sequentially, each of which were split into two oxygen periods with 5 d of unmanipulated oxygen levels (50-70 %), followed by a 5d manipulated oxygen period (16.00-08.00 hours) with low oxygen (40-50 %) levels. For both diets, catabolic protein usage was lowest at 16°C and was not altered under challenging oxygen conditions. Low night-time oxygen elevated mean daily VO2 by 3-14 % compared with the unmanipulated oxygen period for both diets at all temperatures. The relative change in VO2 and retained energy during the intermittent low oxygen period was smaller for the HP diet compared with the SP diet. However, in absolute terms, the SP diet was superior to the HP diet as the former demonstrated 30-40 % lower protein fuel use rates, higher retained energy (1-4 % digestible energy) and slightly lowered VO2 (0-8 %) over the range of conditions tested. The decrease in retained energy under low oxygen conditions suggests that there is scope to improve the performance of SP diets under challenging conditions; however, this study suggests that simply increasing the dietary protein content is not a remedy, and other strategies need to be explored.

FIELD MEASUREMENT OF DISSOLVED OXYGEN: A COMPARISON OF TECHNIQUES

EPA Science Inventory

The measurement and interpretation of geochemical redox parameters are key components of ground water remedial investigations. Dissolved oxygen (DO) is perhaps the most robust geochemical parameter in redox characterization; however, recent work has indicated a need for proper da...

Estimation of Scale Deposition in the Water Walls of an Operating Indian Coal Fired Boiler: Predictive Modeling Approach Using Artificial Neural Networks

NASA Astrophysics Data System (ADS)

Kumari, Amrita; Das, Suchandan Kumar; Srivastava, Prem Kumar

2016-04-01

Application of computational intelligence for predicting industrial processes has been in extensive use in various industrial sectors including power sector industry. An ANN model using multi-layer perceptron philosophy has been proposed in this paper to predict the deposition behaviors of oxide scale on waterwall tubes of a coal fired boiler. The input parameters comprises of boiler water chemistry and associated operating parameters, such as, pH, alkalinity, total dissolved solids, specific conductivity, iron and dissolved oxygen concentration of the feed water and local heat flux on boiler tube. An efficient gradient based network optimization algorithm has been employed to minimize neural predictions errors. Effects of heat flux, iron content, pH and the concentrations of total dissolved solids in feed water and other operating variables on the scale deposition behavior have been studied. It has been observed that heat flux, iron content and pH of the feed water have a relatively prime influence on the rate of oxide scale deposition in water walls of an Indian boiler. Reasonably good agreement between ANN model predictions and the measured values of oxide scale deposition rate has been observed which is corroborated by the regression fit between these values.

Transport of dissolved gases through unsaturated porous media

NASA Astrophysics Data System (ADS)

Maryshev, B. S.

2017-06-01

The natural porous media (e.g. soil, sand, peat etc.) usually are partially saturated by groundwater. The saturation of soil depends on hydrostatic pressure which is linearly increased with depth. Often some gases (e.g. nitrogen, oxygen, carbon dioxide, methane etc.) are dissolved into the groundwater. The solubility of gases is very small because of that two assumptions is applied: I. The concentration of gas is equal to solubility, II. Solubility depends only on pressure (for isothermal systems). In this way some part of dissolved gas transfers from the solution to the bubble phase. The gas bubbles are immovably trapped in a porous matrix by surface-tension forces and the dominant mechanism of transport of gas mass becomes the diffusion of gas molecules through the liquid. If the value of water content is small then the transport of gas becomes slow and gas accumulates into bubble phase. The presence of bubble phase additionally decreases the water content and slows down the transport. As result the significant mass of gas should be accumulated into the massif of porous media. We derive the transport equations and find the solution which is demonstrated the accumulation of gases. The influence of saturation, porosity and filtration velocity to accumulation process is investigated and discussed.

Nano-Enriched and Autonomous Sensing Framework for Dissolved Oxygen.

PubMed

Shehata, Nader; Azab, Mohammed; Kandas, Ishac; Meehan, Kathleen

2015-08-14

This paper investigates a nano-enhanced wireless sensing framework for dissolved oxygen (DO). The system integrates a nanosensor that employs cerium oxide (ceria) nanoparticles to monitor the concentration of DO in aqueous media via optical fluorescence quenching. We propose a comprehensive sensing framework with the nanosensor equipped with a digital interface where the sensor output is digitized and dispatched wirelessly to a trustworthy data collection and analysis framework for consolidation and information extraction. The proposed system collects and processes the sensor readings to provide clear indications about the current or the anticipated dissolved oxygen levels in the aqueous media.

Response of estuarine biofilm microbial community development to changes in dissolved oxygen and nutrient concentrations.

PubMed

Nocker, Andreas; Lepo, Joe Eugene; Martin, Linda Lin; Snyder, Richard Allan

2007-10-01

The information content and responsiveness of microbial biofilm community structure, as an integrative indicator of water quality, was assessed against short-term changes in oxygen and nutrient loading in an open-water estuarine setting. Biofilms were grown for 7-day periods on artificial substrates in the Pensacola Bay estuary, Florida, in the vicinity of a wastewater treatment plant (WWTP) outfall and a nearby reference site. Substrates were deployed floating at the surface and near the benthos in 5.4 m of water. Three sampling events covered a 1-month period coincident with declining seasonal WWTP flow and increasing dissolved oxygen (DO) levels in the bottom waters. Biomass accumulation in benthic biofilms appeared to be controlled by oxygen rather than nutrients. The overriding effect of DO was also seen in DNA fingerprints of community structure by terminal restriction fragment length polymorphism (T-RFLP) of amplified 16S rRNA genes. Ribotype diversity in benthic biofilms at both sites dramatically increased during the transition from hypoxic to normoxic. Terminal restriction fragment length polymorphism patterns showed pronounced differences between benthic and surface biofilm communities from the same site in terms of signal type, strength, and diversity, but minor differences between sites. Sequencing of 16S rRNA gene clone libraries from benthic biofilms at the WWTP site suggested that low DO levels favored sulfate-reducing prokaryotes (SRP), which decreased with rising oxygen levels and increasing overall diversity. A 91-bp ribotype in the CfoI-restricted 16S rRNA gene T-RFLP profiles, indicative of SRP, tracked the decrease in relative SRP abundance over time.

Soil property control of biogeochemical processes beneath two subtropical stormwater infiltration basins

USGS Publications Warehouse

O'Reilly, Andrew M.; Wanielista, Martin P.; Chang, Ni-Bin; Harris, Willie G.; Xuan, Zhemin

2012-01-01

Substantially different biogeochemical processes affecting nitrogen fate and transport were observed beneath two stormwater infiltration basins in north-central Florida. Differences are related to soil textural properties that deeply link hydroclimatic conditions with soil moisture variations in a humid, subtropical climate. During 2008, shallow groundwater beneath the basin with predominantly clayey soils (median, 41% silt+clay) exhibited decreases in dissolved oxygen from 3.8 to 0.1 mg L-1 and decreases in nitrate nitrogen (NO3-–N) from 2.7 mg L-1 to -1, followed by manganese and iron reduction, sulfate reduction, and methanogenesis. In contrast, beneath the basin with predominantly sandy soils (median, 2% silt+clay), aerobic conditions persisted from 2007 through 2009 (dissolved oxygen, 5.0–7.8 mg L-1), resulting in NO3-–N of 1.3 to 3.3 mg L-1 in shallow groundwater. Enrichment of d15N and d18O of NO3- combined with water chemistry data indicates denitrification beneath the clayey basin and relatively conservative NO3- transport beneath the sandy basin. Soil-extractable NO3-–N was significantly lower and the copper-containing nitrite reductase gene density was significantly higher beneath the clayey basin. Differences in moisture retention capacity between fine- and coarse-textured soils resulted in median volumetric gas-phase contents of 0.04 beneath the clayey basin and 0.19 beneath the sandy basin, inhibiting surface/subsurface oxygen exchange beneath the clayey basin. Results can inform development of soil amendments to maintain elevated moisture content in shallow soils of stormwater infiltration basins, which can be incorporated in improved best management practices to mitigate NO3- impacts.

Soil property control of biogeochemical processes beneath two subtropical stormwater infiltration basins.

PubMed

O'Reilly, Andrew M; Wanielista, Martin P; Chang, Ni-Bin; Harris, Willie G; Xuan, Zhemin

2012-01-01

Substantially different biogeochemical processes affecting nitrogen fate and transport were observed beneath two stormwater infiltration basins in north-central Florida. Differences are related to soil textural properties that deeply link hydroclimatic conditions with soil moisture variations in a humid, subtropical climate. During 2008, shallow groundwater beneath the basin with predominantly clayey soils (median, 41% silt+clay) exhibited decreases in dissolved oxygen from 3.8 to 0.1 mg L and decreases in nitrate nitrogen (NO-N) from 2.7 mg L to <0.016 mg L, followed by manganese and iron reduction, sulfate reduction, and methanogenesis. In contrast, beneath the basin with predominantly sandy soils (median, 2% silt+clay), aerobic conditions persisted from 2007 through 2009 (dissolved oxygen, 5.0-7.8 mg L), resulting in NO-N of 1.3 to 3.3 mg L in shallow groundwater. Enrichment of δN and δO of NO combined with water chemistry data indicates denitrification beneath the clayey basin and relatively conservative NO transport beneath the sandy basin. Soil-extractable NO-N was significantly lower and the copper-containing nitrite reductase gene density was significantly higher beneath the clayey basin. Differences in moisture retention capacity between fine- and coarse-textured soils resulted in median volumetric gas-phase contents of 0.04 beneath the clayey basin and 0.19 beneath the sandy basin, inhibiting surface/subsurface oxygen exchange beneath the clayey basin. Results can inform development of soil amendments to maintain elevated moisture content in shallow soils of stormwater infiltration basins, which can be incorporated in improved best management practices to mitigate NO impacts. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

Image analyzing method to evaluate in situ bioluminescence from an obligate anaerobe cultivated under various dissolved oxygen concentrations.

PubMed

Ninomiya, Kazuaki; Yamada, Ryuji; Matsumoto, Masami; Fukiya, Satoru; Katayama, Takane; Ogino, Chiaki; Shimizu, Nobuaki

2013-02-01

An image analyzing method was developed to evaluate in situ bioluminescence expression, without exposing the culture sample to the ambient oxygen atmosphere. Using this method, we investigated the effect of dissolved oxygen concentration on bioluminescence from an obligate anaerobe Bifidobacterium longum expressing bacterial luciferase which catalyzes an oxygen-requiring bioluminescent reaction. Copyright © 2012 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

Dissolved-oxygen regime of the Jordan River, Salt Lake County, Utah

USGS Publications Warehouse

Stephens, D.W.

1984-01-01

Concentrations of dissolved oxygen in the Jordan River in Salt Lake County decrease considerably as the river flows northward. Mean concentrations of dissolved oxygen decreased from 8.1 milligrams per liter at the Jordan Narrows to 4.7 milligrams per liter at 500 North Street during April 1981 to September 1982. Coincident with the decrease, the biochemical-oxygen demand increased from 5 to 7 milligrams per liter. About 50 percent of the dissolved-oxygen concentrations and 90 percent of the 5-day biochemical-oxygen demand measured downstream from 1700 South Street exceeded the State intended-use standards. An estimated 6. million pounds of oxygen-demanding substances as measured by 5-day biochemical-oxygen demand were discharged to the Jordan River during 1981 from point sources downstream from 9000 South Street. Seven wastewater-treatment plants contributed 77 percent of this load, nonstorm base flows contributed 22 percent, and storm flows less than 1 percent. The Surplus Canal diversion at 2100 South Street removed about 70 percent of this load, and travel time of about 1 day also decreased the actual effects of the load on the river. Reaeration rates during September and October were quite high (average K2 at 20 degrees Celsius was about 12 per day) between the Jordan Narrows and 9000 South Street, but they decreased to 2.4 per day in the reach from 1330 South to 1800 North Streets. (USGS)

Oxygen-charged HTK-F6H8 emulsion reduces ischemia-reperfusion injury in kidneys from brain-dead pigs.

PubMed

Asif, Sana; Sedigh, Amir; Nordström, Johan; Brandhorst, Heide; Jorns, Carl; Lorant, Tomas; Larsson, Erik; Magnusson, Peetra U; Nowak, Greg; Theisinger, Sonja; Hoeger, Simone; Wennberg, Lars; Korsgren, Olle; Brandhorst, Daniel

2012-12-01

Prolonged cold ischemia is frequently associated with a greater risk of delayed graft function and enhanced graft failure. We hypothesized that media, combining a high oxygen-dissolving capacity with specific qualities of organ preservation solutions, would be more efficient in reducing immediate ischemia-reperfusion injury from organs stored long term compared with standard preservation media. Kidneys retrieved from brain-dead pigs were flushed using either cold histidine-tryptophan-ketoglutarate (HTK) or oxygen-precharged emulsion composed of 75% HTK and 25% perfluorohexyloctane. After 18 h of cold ischemia the kidneys were transplanted into allogeneic recipients and assessed for adenosine triphosphate content, morphology, and expression of genes related to hypoxia, environmental stress, inflammation, and apoptosis. Compared with HTK-flushed kidneys, organs preserved using oxygen-precharged HTK-perfluorohexyloctane emulsion had increased elevated adenosine triphosphate content and a significantly lower gene expression of hypoxia inducible factor-1α, vascular endothelial growth factor, interleukin-1α, tumor necrosis factor-α, interferon-α, JNK-1, p38, cytochrome-c, Bax, caspase-8, and caspase-3 at all time points assessed. In contrast, the mRNA expression of Bcl-2 was significantly increased. The present study has demonstrated that in brain-dead pigs the perfusion of kidneys with oxygen-precharged HTK-perfluorohexyloctane emulsion results in significantly reduced inflammation, hypoxic injury, and apoptosis and cellular integrity and energy content are well maintained. Histologic examination revealed less tubular, vascular, and glomerular changes in the emulsion-perfused tissue compared with the HTK-perfused counterparts. The concept of perfusing organs with oxygen-precharged emulsion based on organ preservation media represents an efficient alternative for improved organ preservation. Copyright © 2012 Elsevier Inc. All rights reserved.

Microfluidic dissolved oxygen gradient generator biochip as a useful tool in bacterial biofilm studies.

PubMed

Skolimowski, Maciej; Nielsen, Martin Weiss; Emnéus, Jenny; Molin, Søren; Taboryski, Rafael; Sternberg, Claus; Dufva, Martin; Geschke, Oliver

2010-08-21

A microfluidic chip for generation of gradients of dissolved oxygen was designed, fabricated and tested. The novel way of active oxygen depletion through a gas permeable membrane was applied. Numerical simulations for generation of O(2) gradients were correlated with measured oxygen concentrations. The developed microsystem was used to study growth patterns of the bacterium Pseudomonas aeruginosa in medium with different oxygen concentrations. The results showed that attachment of Pseudomonas aeruginosa to the substrate changed with oxygen concentration. This demonstrates that the device can be used for studies requiring controlled oxygen levels and for future studies of microaerobic and anaerobic conditions.

The distribution of nutrients, dissolved oxygen and chlorophyll a in the upper Gulf of Nicoya, Costa Rica, a tropical estuary.

PubMed

Palter, Jaime; Coto, Sandra León; Ballestero, Daniel

2007-06-01

In the Gulf of Nicoya on the Pacific Coast of Costa Rica, nutrient rich equatorial subsurface water (ESW) is upwelled in much of the lower gulf. These offshore waters are often regarded as the major source of nutrients to the gulf. However, for most of the year, the ESW has little influence on the nutrient content of the upper gulf, which has a distinct character from the lower gulf. The upper gulf, extending 40 km north of the restriction between Puntarenas Peninsula and San Lucas Island, is bordered primarily by mangrove swamps, is less than 20 m deep, and is less saline than the lower gulf. We surveyed the upper gulf for dissolved inorganic nitrogen, phosphate, silicate, dissolved oxygen, and chlorophyll in November 2000, January and July 2001. All nutrients are more concentrated in the upper gulf during the rainy and transitional seasons than the dry season, significantly so for phosphate and silicate. Throughout the year, nutrients tend to be much more concentrated in the less saline water of the upper gulf. This trend indicates that discharge from the Tempisque River predominantly controls spatial and temporal nutrient variability in the upper gulf. However, nutrient rich ESW, upwelled offshore and mixed to form a mid-temperature intermediate water, may enter the inner gulf to provide an important secondary source of nutrients during the dry season.

Structural Integrity of Water Reactor Pressure Boundary Components.

DTIC Science & Technology

1981-02-20

environment, and load waveform parameters . A theory of the influence of dissolved oxygen content on the fatigue crack growth results in simulated PWR ...simulated PWR coolant is - (Continues ) DD IJN7 1473 EDITION OF I NOV S ..OSL- -C 2 S/ 0102-LF-014-6601 S1ECURITY CLASSI1FICATION OF THIS PAGE (When...not seem to influence the data, which was produced for a load ratio of 0.2 and a simulated PWR coolant environment. Test results for A106 Grade C piping

Thermodynamic approach to oxygen delivery in vivo by natural and artificial oxygen carriers.

PubMed

Bucci, Enrico

2009-06-01

Oxygen is a toxic gas, still indispensable to aerobic life. This paper explores how normal physiology uses the physico-chemical and thermodynamic characteristics of oxygen for transforming a toxic gas into a non toxic indispensable metabolite. Plasma oxygen concentration is in the range of 10(-5) M, insufficient to sustain metabolism. Oxygen carriers, present in blood, release oxygen into plasma, thereby replacing consumed oxygen and buffering PO(2) near their P(50). They are the natural cell-bound carriers, like hemoglobin inside red cells, myoglobin inside myocytes, and artificial cell-free hemoglobin-based oxygen carriers (HBOC) dissolved in plasma. Metabolic oxygen replacement can be defined as cell-bound and cell-free delivery. Cell-bound delivery is retarded by the slow diffusion of oxygen in plasma and interstitial fluids. The 40% hematocrit of normal blood compensates for the delay, coping with the fast oxygen consumption by mitochondria. Facilitated oxygen diffusion by HBOCs corrects for the slow diffusion, making cell-free delivery relatively independent from P(50). At all oxygen affinities, HBOCs produce hyperoxygenations that are compensated by vasoconstrictions. There is a strict direct correlation between the rate of oxygen replacement and hemoglobin content of blood. The free energy loss of the gradient adds a relevant regulation of tissues oxygenation. Oxygen is retained intravascularly by the limited permeability to gases of vessel walls.

Combined effects of acidification and hypoxia on the estuarine ctenophore, Mnemiopsis leidyi

EPA Science Inventory

Estuaries are transitive zones which experience large fluctuations in environmental parameters (temperature, dissolved oxygen, pH, etc.). The interactive effects of reduced dissolved oxygen (DO) and elevated pCO2 on estuarine organisms is not currently well understood. Ctenophore...

RELATIONSHIPS BETWEEN NEAR-BOTTOM DISSOLVED OXYGEN AND SEDIMENT PROFILE CAMERA MEASUREMENTS

EPA Science Inventory

The United States Environmental Protection Agency (U.S. EPA) and other environmental authorities regulate concentrations of dissolved oxygen (DO) as a measure of nutrient-related eutrophication in estuarine and coastal waters. However, in situ DO concentrations are extremely var...

River Pollution: Part I.

ERIC Educational Resources Information Center

Openshaw, Peter

1983-01-01

Describes a unit on river pollution and analytical methods to use in assessing temperature, pH, flow, calcium, chloride, dissolved oxygen, biochemical oxygen demand, dissolved nitrogen, detergents, heavy metals, sewage pollution, conductivity, and sediment cores. Suggests tests to be carried out and discusses significance of results. (JM)

SIMULATION OF DISSOLVED OXYGEN PROFILES IN A TRANSPARENT, DIMICTIC LAKE

EPA Science Inventory

Thrush Lake is a small, highly transparent lake in northeastern Minnesota. rom 1986 to 1991, vertical profiles of water temperature, dissolved oxygen, chlorophyll a concentration, underwater light irradiance, and Secchi depths were measured at monthly intervals during the ice-fre...

Simple method to make a supersaturated oxygen fluid.

PubMed

Tange, Yoshihiro; Yoshitake, Shigenori; Takesawa, Shingo

2018-01-22

Intravenous oxygenation has demonstrated significant increase in partial pressure of oxygen (PO 2 ) in animal models. A highly dissolved oxygen solution might be able to provide a sufficient level of oxygen delivery to the tissues and organs in patients with hypoxia. However, conventional fluid oxygenation methods have required the use of original devices. If simpler oxygenation of a solution is possible, it will be a useful strategy for application in clinical practice. We simply developed its administration by injection of either air or oxygen gas into conventional saline. We determined the PO 2 values in the solutions in comparison with conventional saline in vitro. To examine the effects of the administration of the new solutions on the blood gas profile, we diluted bovine blood with either conventional or the new solutions and analyzed PO 2 , oxygen saturation (SO 2 ) and total oxygen content. PO 2 levels in the blood and new solution mixture significantly increased with each additional injected gas volume. Significant increases in the PO 2 and SO 2 of the bovine blood were found in those blood samples with the new solution, as compared with those with the control solution. These results suggest that this solution promotes oxygen delivery to the hypoxic tissue and recovery from hypoxia. This method is simpler and easier than previous methods.

Optical fiber-mediated photosynthesis for enhanced subsurface oxygen delivery.

PubMed

Lanzarini-Lopes, Mariana; Delgado, Anca G; Guo, Yuanming; Dahlen, Paul; Westerhoff, Paul

2018-03-01

Remediation of polluted groundwater often requires oxygen delivery into subsurface to sustain aerobic bacteria. Air sparging or injection of oxygen containing solutions (e.g., hydrogen peroxide) into the subsurface are common. In this study visible light was delivered into the subsurface using radially emitting optical fibers. Phototrophic organisms grew near the optical fiber in a saturated sand column. When applying light in on-off cycles, dissolved oxygen (DO) varied from super saturation levels of >15 mg DO/L in presence of light to under-saturation (<5 mg DO/L) in absence of light. Non-photosynthetic bacteria dominated at longer radial distances from the fiber, presumably supported by soluble microbial products produced by the photosynthetic microorganisms. The dissolved oxygen variations alter redox condition changes in response to light demonstrate the potential to biologically deliver oxygen into the subsurface and support a diverse microbial community. The ability to deliver oxygen and modulate redox conditions on diurnal cycles using solar light may provide a sustainable, long term strategy for increasing dissolved oxygen levels in subsurface environments and maintaining diverse biological communities. Copyright © 2017 Elsevier Ltd. All rights reserved.

Effect of dissolved oxygen on biological denitrification using biodegradable plastic as the carbon source

NASA Astrophysics Data System (ADS)

Zhang, Xucai; Zhang, Jianmei

2018-02-01

Biological denitrification is currently a common approach to remove nitrate from wastewater. This study was conducted to evaluate the influence of dissolved oxygen on denitrification in wastewater treatment using biodegradable plastic as carbon source by designing the aerated, anoxic, and low-oxygen experimental treatment groups. The results showed that the removal rates of nitrate in anoxic and low-oxygen groups were 30.6 g NO3 --Nm-3 d-1 and 30.8 g NO3 --N m-3 d-1 at 83 h, respectively, both of which were higher than that of the aerated group. There was no significant difference between the anoxic and low-oxygen treatment groups for the nitrate removal. Additional, the nitrite accumulated during the experiments, and the nitrite concentrations in anoxic and aerated groups were lower than those in low-oxygen group. No nitrite was detected in all groups at the end of the experiments. These findings indicated that dissolved oxygen has important influence on denitrification, and anoxic and low-oxygen conditions can support completely denitrification when using BP as carbon source in nitrate-polluted wastewater treatment.

A dissolved cobalt plume in the oxygen minimum zone of the eastern tropical South Pacific

NASA Astrophysics Data System (ADS)

Hawco, Nicholas J.; Ohnemus, Daniel C.; Resing, Joseph A.; Twining, Benjamin S.; Saito, Mak A.

2016-10-01

Cobalt is a nutrient to phytoplankton, but knowledge about its biogeochemical cycling is limited, especially in the Pacific Ocean. Here, we report sections of dissolved cobalt and labile dissolved cobalt from the US GEOTRACES GP16 transect in the South Pacific. The cobalt distribution is closely tied to the extent and intensity of the oxygen minimum zone in the eastern South Pacific with highest concentrations measured at the oxycline near the Peru margin. Below 200 m, remineralization and circulation produce an inverse relationship between cobalt and dissolved oxygen that extends throughout the basin. Within the oxygen minimum zone, elevated concentrations of labile cobalt are generated by input from coastal sources and reduced scavenging at low O2. As these high cobalt waters are upwelled and advected offshore, phytoplankton export returns cobalt to low-oxygen water masses underneath. West of the Peru upwelling region, dissolved cobalt is less than 10 pM in the euphotic zone and strongly bound by organic ligands. Because the cobalt nutricline within the South Pacific gyre is deeper than in oligotrophic regions in the North and South Atlantic, cobalt involved in sustaining phytoplankton productivity in the gyre is heavily recycled and ultimately arrives from lateral transport of upwelled waters from the eastern margin. In contrast to large coastal inputs, atmospheric deposition and hydrothermal vents along the East Pacific Rise appear to be minor sources of cobalt. Overall, these results demonstrate that oxygen biogeochemistry exerts a strong influence on cobalt cycling.

Assessment of oceanic productivity with the triple-isotope composition of dissolved oxygen.

PubMed

Luz, B; Barkan, E

2000-06-16

Plant production in the sea is a primary mechanism of global oxygen formation and carbon fixation. For this reason, and also because the ocean is a major sink for fossil fuel carbon dioxide, much attention has been given to estimating marine primary production. Here, we describe an approach for estimating production of photosynthetic oxygen, based on the isotopic composition of dissolved oxygen of seawater. This method allows the estimation of integrated oceanic productivity on a time scale of weeks.

The Influence of Physical Forcing on Bottom-water Dissolved Oxygen within the Caloosahatchee River Estuary, FL

EPA Science Inventory

Environmental Fluid Dynamic Code (EFDC), a numerical estuarine and coastal ocean circulation hydrodynamic model, was used to simulate the distribution of dissolved oxygen (DO), salinity, temperature, nutrients (nitrogen and phosphorus), and chlorophyll a in the Caloosahatchee Riv...

Modeling Fish Growth in Low Dissolved Oxygen

ERIC Educational Resources Information Center

Neilan, Rachael Miller

2013-01-01

This article describes a computational project designed for undergraduate students as an introduction to mathematical modeling. Students use an ordinary differential equation to describe fish weight and assume the instantaneous growth rate depends on the concentration of dissolved oxygen. Published laboratory experiments suggest that continuous…

FIELD MEASUREMENT OF DISSOLVED OXYGEN: A COMPARISON OF METHODS

EPA Science Inventory

The ability to confidently measure the concentration of dissolved oxygen (D.O.) in ground water is a key aspect of remedial selection and assessment. Presented here is a comparison of the commonly practiced methods for determining D.O. concentrations in ground water, including c...

FIELD MEASUREMENT OF DISSOLVED OXYGEN: A COMPARISON OF METHODS: JOURNAL ARTICLE

EPA Science Inventory

NRMRL-ADA- 00160 Wilkin*, R.T., McNeil*, M.S., Adair*, C.J., and Wilson*, J.T. Field Measurement of Dissolved Oxygen: A Comparison of Methods. Ground Water Monitoring and Remediation (Fall):124-132 (2001). EPA/600/J-01/403. The abili...

Bubble growth as a means to measure dissolved nitrogen concentration in aerated water

NASA Astrophysics Data System (ADS)

Ando, Keita; Yamashita, Tatsuya

2017-11-01

Controlling the amount of dissolved gases in water is important, for example, to food processing; it is essential to quantitatively evaluate dissolved gas concentration. The concentration of dissolved oxygen (DO) can be measured by commercial DO meters, but that of dissolved nitrogen (DN) cannot be obtained easily. Here, we propose a means to measure DN concentration based on Epstein-Plesset-type analysis of bubble growth under dissolved gas supersaturation. DO supersaturation in water is produced by oxygen microbubble aeration. The diffusion-driven growth of bubbles nucleated at glass surfaces in contact with the aerated water is first observed. The observed growth is then compared to the extended Epstein-Plesset theory that considers Fick's mass transfer of both DO and DN across bubble interfaces; in this comparison, the unknown DN concentration is treated as a fitting parameter. Comparisons between the experiment and the theory suggest, as expected, that DN can be effectively purged by oxygen microbubble aeration. This study was supported in part by the Mizuho Foundation for the Promotion of Science and by a MEXT Grant-in-Aid for the Program for Leading Graduate Schools.

Drought effects on water quality in the South Platte River Basin, Colorado

USGS Publications Warehouse

Sprague, Lori A.

2005-01-01

Twenty-three stream sites representing a range of forested, agricultural, and urban land uses were sampled in the South Platte River Basin of Colorado from July through September 2002 to characterize water quality during drought conditions. With a few exceptions, dissolved ammonia, Kjeldahl nitrogen, total phosphorus, and dissolved orthophosphate concentrations were similar to seasonal historical levels in all land use areas during the drought. At some agricultural sites, decreased dilution of irrigation return flow may have contributed to higher concentrations of some nutrient species, increased primary productivity, and higher dissolved oxygen concentrations. At some urban sites, decreased dilution of base flow and wastewater treatment plant effluent may have contributed to higher dissolved nitrite-plus-nitrate concentrations, increased primary productivity, and higher dissolved oxygen concentrations. Total pesticide concentrations in urban and agricultural areas were not consistently higher or lower during the drought. At most forested sites, decreased dilution of ground water-derived calcium bicarbonate type base flow likely led to elevated pH and specific-conductance values. Water temperatures at many of the forested sites also were higher, contributing to lower dissolved oxygen concentrations during the drought.

Effects of Environmental and Anthropogenic Factors on Water Quality in the Rock Creek Watershed

DTIC Science & Technology

2016-04-08

factors playing an augmenting role. The authors found a seasonal relationship with temperature , pH, and dissolved oxygen (DO). Additionally, they...2011 ), and nutrients (2013). In 1994, a Public Health Advisory ( fish consumption advisory) which is still in place today, was issued by the D.C...Dissolved Solids (TDS) Escherichia coli (E.coli) Temperature Dissolved Oxygen (DO) Total Colifonns - Electrical Conductivity (EC) Nitrate (N03-N

Electrochemically reduced water exerts superior reactive oxygen species scavenging activity in HT1080 cells than the equivalent level of hydrogen-dissolved water

PubMed Central

Hamasaki, Takeki; Harada, Gakuro; Nakamichi, Noboru; Kabayama, Shigeru; Teruya, Kiichiro; Fugetsu, Bunshi; Gong, Wei; Sakata, Ichiro; Shirahata, Sanetaka

2017-01-01

Electrochemically reduced water (ERW) is produced near a cathode during electrolysis and exhibits an alkaline pH, contains richly dissolved hydrogen, and contains a small amount of platinum nanoparticles. ERW has reactive oxygen species (ROS)-scavenging activity and recent studies demonstrated that hydrogen-dissolved water exhibits ROS-scavenging activity. Thus, the antioxidative capacity of ERW is postulated to be dependent on the presence of hydrogen levels; however, there is no report verifying the role of dissolved hydrogen in ERW. In this report, we clarify whether the responsive factor for antioxidative activity in ERW is dissolved hydrogen. The intracellular ROS scavenging activity of ERW and hydrogen-dissolved water was tested by both fluorescent stain method and immuno spin trapping assay. We confirm that ERW possessed electrolysis intensity-dependent intracellular ROS-scavenging activity, and ERW exerts significantly superior ROS-scavenging activity in HT1080 cells than the equivalent level of hydrogen-dissolved water. ERW retained its ROS-scavenging activity after removal of dissolved hydrogen, but lost its activity when autoclaved. An oxygen radical absorbance capacity assay, the 2,2-diphenyl-1-picrylhydrazyl assay and chemiluminescence assay could not detect radical-scavenging activity in both ERW and hydrogen-dissolved water. These results indicate that ERW contains electrolysis-dependent hydrogen and an additional antioxidative factor predicted to be platinum nanoparticles. PMID:28182635

Electrochemically reduced water exerts superior reactive oxygen species scavenging activity in HT1080 cells than the equivalent level of hydrogen-dissolved water.

PubMed

Hamasaki, Takeki; Harada, Gakuro; Nakamichi, Noboru; Kabayama, Shigeru; Teruya, Kiichiro; Fugetsu, Bunshi; Gong, Wei; Sakata, Ichiro; Shirahata, Sanetaka

2017-01-01

Electrochemically reduced water (ERW) is produced near a cathode during electrolysis and exhibits an alkaline pH, contains richly dissolved hydrogen, and contains a small amount of platinum nanoparticles. ERW has reactive oxygen species (ROS)-scavenging activity and recent studies demonstrated that hydrogen-dissolved water exhibits ROS-scavenging activity. Thus, the antioxidative capacity of ERW is postulated to be dependent on the presence of hydrogen levels; however, there is no report verifying the role of dissolved hydrogen in ERW. In this report, we clarify whether the responsive factor for antioxidative activity in ERW is dissolved hydrogen. The intracellular ROS scavenging activity of ERW and hydrogen-dissolved water was tested by both fluorescent stain method and immuno spin trapping assay. We confirm that ERW possessed electrolysis intensity-dependent intracellular ROS-scavenging activity, and ERW exerts significantly superior ROS-scavenging activity in HT1080 cells than the equivalent level of hydrogen-dissolved water. ERW retained its ROS-scavenging activity after removal of dissolved hydrogen, but lost its activity when autoclaved. An oxygen radical absorbance capacity assay, the 2,2-diphenyl-1-picrylhydrazyl assay and chemiluminescence assay could not detect radical-scavenging activity in both ERW and hydrogen-dissolved water. These results indicate that ERW contains electrolysis-dependent hydrogen and an additional antioxidative factor predicted to be platinum nanoparticles.

Analysis on the Upwelling of the Anoxic Water Mass in Inner Tokyo Bay

NASA Astrophysics Data System (ADS)

Kitahara, Kouichi; Wada, Akira; Kawanaga, Mitsuhito; Fukuoka, Ippei; Takano, Tairyu

In the period of strong density stratification from early summer through early fall, the supply of oxygen from the sea surface to the deeper water is cut off. At the same time, organic matter decomposes near the ocean bottom, so that the anoxic water mass forms. In inner Tokyo Bay, when a northeasterly wind(directed from the inner bay toward the mouth of the bay)blows, the anoxic water mass upwells(an “Aoshio” occurs). In some cases fishes and shellfish die along the coast. Based on the report of results of continuous observations of water temperature, salinity and dissolved oxygen content presented by Fukuoka et al, 2005, here we have used an improved fluid flow model to carry out 3-dimensional calculations of the water level, water temperature, salinity and flow distributions. The computational results have reproduced the observational results well. The calculations showed that upwelling of the anoxic water mass that forms during the stratified period is not only affected by the continuously blowing northeasterly wind, but also by a continuous southwesterly wind that blew several days previously. Surface water blown against the coast by this continuous southwesterly wind is pushed downward; the calculations reproduced the process by which the rising force of this previously downwelled surface water also affects the phenomenon of anoxia. Furthermore, we presented the results of time dependent analysis of quantities relevant to water quality, including dissolved oxygen, which is closely related to the Aoshio, using the flow and diffusion model and a primary ecological model during the stratified ocean period, the sinking period and the upwelling period. We have compared the computed results to the results of continuous observations of dissolved oxygen during occurrence of an Aoshio in 1992 at observation point D-2, and confirmed that this model is an appropriate one to describe this phenomenon.

Chemical characteristics of Delaware River water, Trenton, New Jersey, to Marcus Hook, Pennsylvania

USGS Publications Warehouse

Durfor, Charles N.; Keighton, Walter B.

1954-01-01

This progress report gives the results of an investigation of the quality of water in the Delaware River from Trenton, N. J. to Marcus Hook, Pa., for the period August 1949 to December 1952. The Delaware River is the principal source of water for the many industries and municipal water supplies along this reach of the river and both industries and municipalities use it for the disposal of their wastes. Consequently, a study of the quality of the water and variations in the quality caused by changes in streamflow, tidal effects, pollution and other factors is important to the many users. In both New Jersey and Pennsylvania steps are being taken to abate pollution, thus it is of more than passing interest to measure the effects of waste treatment on the quality of the Delaware River water. At average or higher rates of streamflow the mineral content of the water increases slightly from Trenton to Marcus Hook. There is little variation in the concentration of dissolved minerals from bank to bank or from top to bottom of the river. At times of protracted low rates of flow the effect of ocean water mixing with the river water may be noted as far upstream as Philadelphia. At such times the salinity is often greater near the bottom of the river than near the top. The increase in chloride concentration upstream from Philadelphia is small compared to the rapid increase downstream from Philadelphia. Temperatures of offshore water vary with the season, but on a given day are substantially uniform throughout the reach of the river from Trenton to Marcus Hook. The water contains less dissolved oxygen as it flows downstream indicating that oxygen is being consumed by oxidizable matter. From Philadelphia downstream there are periods, especially in late summer, when the dissolved oxygen is barely sufficient to meet the oxygen demands of the pollution load.

Chloramination of nitrogenous contaminants (pharmaceuticals and pesticides): NDMA and halogenated DBPs formation.

PubMed

Le Roux, Julien; Gallard, Hervé; Croué, Jean-Philippe

2011-05-01

Disinfection with chloramines is often used to reduce the production of regulated disinfection by-products (DBPs) such as trihalomethanes (THMs) and haloacetic acids (HAAs). However, chloramination can lead to the formation of N-nitrosamines, including N-nitrosodimethylamine (NDMA), a probable human carcinogen. Previous research used dimethylamine (DMA) as a model precursor of NDMA, but certain widely used tertiary dimethylamines (e.g. the pharmaceutical ranitidine) show much higher conversion rates to NDMA than DMA. This study investigates the NDMA formation potential of several tertiary amines including pharmaceuticals and herbicides. The reactivity of these molecules with monochloramine (NH(2)Cl) is studied through the formation of NDMA, and other halogenated DBPs such as haloacetonitriles (HANs) and AOX (Adsorbable Organic Halides). Several compounds investigated formed NDMA in greater amounts than DMA, revealing the importance of structural characteristics of tertiary amines for NDMA formation. Among these compounds, the pharmaceutical ranitidine showed the highest molar conversion to NDMA. The pH and dissolved oxygen content of the solution were found to play a major role for the formation of NDMA from ranitidine. NDMA was formed in higher amounts at pH around pH 8 and a lower concentration of dissolved oxygen dramatically decreased NDMA yields. These findings seem to indicate that dichloramine (NHCl(2)) is not the major oxidant involved in the formation of NDMA from ranitidine, results in contradiction with the reaction mechanisms proposed in the literature. Dissolved oxygen was also found to influence the formation of other oxygen-containing DBPs (i.e. trichloronitromethane and haloketones). The results of this study identify several anthropogenic precursors of NDMA, indicating that chloramination of waters impacted by these tertiary amines could lead to the formation of significant amounts of NDMA and other non-regulated DBPs of potential health concern (e.g. dichloroacetonitrile or trichloronitromethane). This could be of particular importance for the chloramination of wastewater effluents, especially during water reuse processes. Copyright © 2011 Elsevier Ltd. All rights reserved.

Effects of Metals Associated with Wildfire Ash on Water Quality

NASA Astrophysics Data System (ADS)

Cerrato, J.; Clark, A.; Correa, N.; Ali, A.; Blake, J.; Bixby, R.

2015-12-01

The forests of the western United States are impacted dramatically by climate change and have suffered from large-scale increases in wildfire activity. This rise in wildfires introduces additional ash to ecosystems and can represent a serious and ongoing threat to water quality in streams and rivers from storm event runoff in burn areas. The effect of metals associated with wildfire ash (from wood collected from the Valles Caldera National Preserve, Jemez Mountains, New Mexico) on solution pH and dissolved oxygen was assessed through a series of laboratory experiments. Microscopy and spectroscopy analyses were conducted to characterize the elemental content and oxidation state of metals in unreacted and reacted ash. Certain metals (e.g., Ca, K, Al, Mg) were detected in ash from ponderosa pine, one of the dominant species in the Valles Caldera, with mean concentrations ranging from 400-1750 mg kg-1. Other metals (e.g., Na, Fe, Mn, V, Zn, Ni) were present at lower mean concentrations ranging from 12-210 mg kg-1. The initial pH after conducting batch experiments reacting ash with water started at 9.9 and the alkalinity of the water was 110 mg L-1 as CaCO3. Solution pH decreased to 8.0 after 48 hours of reaction, which is almost a delta of two pH units. Dissolved oxygen concentrations decreased by 2 mg L-1 over the course of 12 hours before the rate of reaeration surpassed the rate of consumption. This presentation will discuss how redox-active metals, such as Fe and Mn, could contribute to the increased dissolved oxygen demand and fluctuation of the oxidation/reduction potential in the system.

Living with a large reduction in permited loading by using a hydrograph-controlled release scheme

USGS Publications Warehouse

Conrads, P.A.; Martello, W.P.; Sullins, N.R.

2003-01-01

The Total Maximum Daily Load (TMDL) for ammonia and biochemical oxygen demand for the Pee Dee, Waccamaw, and Atlantic Intracoastal Waterway system near Myrtle Beach, South Carolina, mandated a 60-percent reduction in point-source loading. For waters with a naturally low background dissolved-oxygen concentrations, South Carolina anti-degradation rules in the water-quality regulations allows a permitted discharger a reduction of dissolved oxygen of 0.1 milligrams per liter (mg/L). This is known as the "0.1 rule." Permitted dischargers within this region of the State operate under the "0.1 rule" and cannot cause a cumulative impact greater than 0.1 mg/L on dissolved-oxygen concentrations. For municipal water-reclamation facilities to serve the rapidly growing resort and retirement community near Myrtle Beach, a variable loading scheme was developed to allow dischargers to utilize increased assimilative capacity during higher streamflow conditions while still meeting the requirements of a recently established TMDL. As part of the TMDL development, an extensive real-time data-collection network was established in the lower Waccamaw and Pee Dee River watershed where continuous measurements of streamflow, water level, dissolved oxygen, temperature, and specific conductance are collected. In addition, the dynamic BRANCH/BLTM models were calibrated and validated to simulate the water quality and tidal dynamics of the system. The assimilative capacities for various streamflows were also analyzed. The variable-loading scheme established total loadings for three streamflow levels. Model simulations show the results from the additional loading to be less than a 0.1 mg/L reduction in dissolved oxygen. As part of the loading scheme, the real-time network was redesigned to monitor streamflow entering the study area and water-quality conditions in the location of dissolved-oxygen "sags." The study reveals how one group of permit holders used a variable-loading scheme to implement restrictive permit limits without experiencing prohibitive capital expenditures or initiating a lengthy appeals process.

Lipid Content and Cryotolerance of Bakers' Yeast in Frozen Doughs †

PubMed Central

Gélinas, Pierre; Fiset, Gisèle; Willemot, Claude; Goulet, Jacques

1991-01-01

The relationship between lipid content and tolerance to freezing at −50°C was studied in Saccharomyces cerevisiae grown under batch or fed-batch mode and various aeration and temperature conditions. A higher free-sterol-to-phospholipid ratio as well as higher free sterol and phospholipid contents correlated with the superior cryoresistance in dough or in water of the fed-batch-grown compared with the batch-grown cells. For both growth modes, the presence of excess dissolved oxygen in the culture medium greatly improved yeast cryoresistance and trehalose content (P. Gélinas, G. Fiset, A. LeDuy, and J. Goulet, Appl. Environ. Microbiol. 26:2453-2459, 1989) without significantly changing the lipid profile. Under the batch or fed-batch modes, no correlation was found between the cryotolerance of bakers' yeast and the total cellular lipid content, the total sterol content, the phospholipid unsaturation index, the phosphate or crude protein content, or the yeast cell morphology (volume and roundness). PMID:16348412

Experimental Oxidation of Iron Sulphides from Intertidal Surface Sediments: Stable Isotope Effects (S, O, C)

NASA Astrophysics Data System (ADS)

Ebersbach, F.; Böttcher, M. E.; Al-Raei, A. M.; Segl, M.

2009-04-01

Top intertidal sediments show a pronounced zone of activities of sulphate-reducing bacteria. Iron sulfides may be formed, but a substantial part is reoxidized to sulfate. Microbial or chemical reoxidation can be further enhanced by a resuspension of surface sediments by tidal currents or storms. The rates of the different processes depend on the site-secific sedimentological properties (e.g., grain size, iron and sulphur contents etc.). In the present study 3 different areas of the German Wadden Sea were studied: a mud flat in the Jade Bay, and sandy sediments in the intertidals of Spiekeroog and Sylt islands. The latter site is part of an in-situ lugworm-exclusion experiment. The goal was the experimental and field investigation of the fate of iron sulfides and the formation of sulphate upon resuspension of intertidal surface sediments in oxygenated seawater. All sites were geochemically analyzed for dissolved and solid phase iron, manganese, sulphur and carbon phases/species, and sulphate reduction rates were measured using radiotracers. Dissolved chloride and grain sizes analysis where additionally carried out. TOC, S and metal phase contents were higher in mud compared to sandy sediments. Field results demonstrate gross but only minor net sulphide production and a downcore increases in FeS contents, due to intense sulphide oxidation at the surface. Pyrite, on the other hand, was abundant through the sediments due to continuous sediment reworking. The fate of iron-sulphides and accumulation of sulphate as a function of time was followed in batch experiments using dark suspensions of surface sediments in site-bottom waters at room temperature. During the experiments, each sample was shaken continuously under exposition to oxygen, and sub-samples were taken at the beginning and after discrete time intervalls. A very fast oxidation rate of AVS led to a complete exhaustion within a day, whereas Cr(II)-reducible sulfur was inititially built up and then decreased. This observation can be explained by a formation of S° and FeOOH, followed by the oxidation of pyrite. The dissolved species (SO4/Cl ratios) reflected the continuous accumulation of sulphate as an oxidation product. Dissolved inorganic carbonate (DIC) concentrations decreased upon reaction progress, due to the liberation of protons upon iron sulphide oxidation and degassing of carbon dioxide. The 13C/12C ratio of the residual DIC increased due to the preferential desorption of 12CO2. 34S and 18O contents of dissolved sulphate further show process specific isotope discrimination. The experiments demonstrate the importance of oxidation on the fate of FeS , but less pyrite and the formation of sulphate from resuspended intertidal surface sediments. Acknowledgements: The authors gratefully acknowledge discussions and field advice by N. Volkenborn, and financial support from Deutsche Forschungsgemeinschaft during DFG-SPP ‚BioGeoChemistry of the Wadden Sea' (JO 307/4, BO 1584/4), Max Planck Society, and Leibniz-IO Warnemünde.

Long-Duration Carbon Dioxide Anesthesia of Fish Using Ultra Fine (Nano-Scale) Bubbles.

PubMed

Kugino, Kenji; Tamaru, Shizuka; Hisatomi, Yuko; Sakaguchi, Tadashi

2016-01-01

We investigated whether adding ultrafine (nano-scale) oxygen-carrying bubbles to water concurrently with dissolved carbon-dioxide (CO2) could result in safe, long-duration anesthesia for fish. To confirm the lethal effects of CO2 alone, fishes were anesthetized with dissolved CO2 in 20°C seawater. Within 30 minutes, all fishes, regardless of species, died suddenly due to CO2-induced narcosis, even when the water was saturated with oxygen. Death was attributed to respiration failure caused by hypoxemia. When ultrafine oxygen-carrying bubbles were supplied along with dissolved CO2, five chicken grunts were able to remain anesthetized for 22 hours and awoke normally within 2-3 hours after cessation of anesthesia. The high internal pressures and oxygen levels of the ultrafine bubbles enabled efficient oxygen diffusion across the branchia and permitted the organismal oxygen demands of individual anesthetized fish to be met. Thus, we demonstrated a method for safe, long-duration carbon dioxide anesthesia in living fish under normal water temperatures.

Dissolved Oxygen Thresholds to Protect Designated Aquatic Life Uses in Estuaries

EPA Science Inventory

Most if not all coastal states in the US have established numeric thresholds for dissolved oxygen (DO) to protect aquatic life in estuaries. Some are in the process, or have recently completed, revisions of their criteria based on newer science. Often, a toxicological approach ...

Numerical Simulation of Salinity and Dissolved Oxygen at Perdido Bay and Adjacent Coastal Ocean

EPA Science Inventory

Environmental Fluid Dynamic Code (EFDC), a numerical estuarine and coastal ocean circulation hydrodynamic model, was used to simulate the distribution of the salinity, temperature, nutrients and dissolved oxygen (DO) in Perdido Bay and adjacent Gulf of Mexico. External forcing fa...

SIMULATED CLIMATE CHANGE EFFECTS ON DISSOLVED OXYGEN CHARACTERISTICS IN ICE-COVERED LAKES. (R824801)

EPA Science Inventory

A deterministic, one-dimensional model is presented which simulates daily dissolved oxygen (DO) profiles and associated water temperatures, ice covers and snow covers for dimictic and polymictic lakes of the temperate zone. The lake parameters required as model input are surface ...

USE OF SEDIMENT PROFILE IMAGERY TO ESTIMATE NEAR-BOTTOM DISSOLVED OXYGEN REGIMES

EPA Science Inventory

The U.S. EPA, Atlantic Ecology Division is developing empirical stressor-response models for nitrogen pollution in partially enclosed coastal systems using dissolved oxygen (DO) as one of the system responses. We are testing a sediment profile image camera as a surrogate indicat...

DISSOLVED OXYGEN AND METHANE IN WATER BY A GC HEADSPACE EQUILIBRATION TECHNIQUE

EPA Science Inventory

An analytical procedure is described for the determination of dissolved oxygen and methane in groundwater samples. The method consists of generating a helium gas headspace in a water filled bottle, and analysis of the headspace by gas chromatography. Other permanent gases such as...

Investigating Factors that Affect Dissolved Oxygen Concentration in Water

ERIC Educational Resources Information Center

Jantzen, Paul G.

1978-01-01

Describes activities that demonstrate the effects of factors such as wind velocity, water temperature, convection currents, intensity of light, rate of photosynthesis, atmospheric pressure, humidity, numbers of decomposers, presence of oxidizable ions, and respiration by plants and animals on the dissolved oxygen concentration in water. (MA)

Kinetic modelling of ascorbic and dehydroascorbic acids concentrations in a model solution at different temperatures and oxygen contents.

PubMed

Gómez Ruiz, Braulio; Roux, Stéphanie; Courtois, Francis; Bonazzi, Catherine

2018-04-01

The degradation kinetics of vitamin C (ascorbic and dehydroascorbic acids, AA and DHA) were determined under controlled conditions of temperature (50-90 °C) and oxygen concentrations in the gas phase (10-30% mol/mol) using a specific reactor. The degradation of vitamin C in malate buffer (20 mM, pH 3.8), mimetic of an apple puree, was assessed by sampling at regular intervals and spectrophotometric quantification of AA and DHA levels at 243 nm. The results showed that AA degradation increased with temperature and oxygen concentration, while DHA exhibited the behaviour of an intermediate species, appearing then disappearing. A kinetic model was successfully developed to simulate the experimental data by two first order consecutive reactions. The first one represented AA degradation as a function of temperature and concentration in dissolved oxygen, and the second reflected DHA degradation as a function of temperature only, both adequately following Arrhenius' law. Copyright © 2018 Elsevier Ltd. All rights reserved.

Biological, Physical and Chemical Data From Gulf of Mexico Gravity and Box Core MRD05-04

USGS Publications Warehouse

Osterman, Lisa E.; Campbell, Pamela L.; Swarzenski, Peter W.; Ricardo, John P.

2010-01-01

This paper presents the benthic foraminiferal census data, magnetic susceptibility measurements, vanadium and organic geochemistry (carbon isotope, sterols, and total organic carbon) data from the MRD05-04 gravity and box cores. The MRD05-04 cores were obtained from the Louisiana continental shelf in an on-going initiative to examine the geographic and temporal extent of hypoxia, low-oxygen bottom-water content, and geochemical transport. The development of low-oxygen bottom water conditions in coastal waters is dependent upon a new source of bio-available nutrients introduced into a well-stratified water column. A number of studies have concluded that the development of the current seasonal hypoxia (dissolved oxygen < 2 mg L-1) in subsurface waters of the northern Gulf of Mexico is related to increased transport of nutrients (primarily nitrogen, but possibly also phosphorous) by the Mississippi River. However, the development of earlier episodes of seasonal low-oxygen subsurface water on the Louisiana shelf may be related to Mississippi River discharge.

An effective device for gas-liquid oxygen removal in enclosed microalgae culture.

PubMed

Su, Zhenfeng; Kang, Ruijuan; Shi, Shaoyuan; Cong, Wei; Cai, Zhaoling

2010-01-01

A high-performance gas-liquid transmission device (HPTD) was described in this paper. To investigate the HPTD mass transfer characteristics, the overall volumetric mass transfer coefficients, K(A)(La,CO(2)) for the absorption of gaseous CO(2) and K(A)(La,O(2)) for the desorption of dissolved O(2) were determined, respectively, by titration and dissolved oxygen electrode. The mass transfer capability of carbon dioxide was compared with that of dissolved oxygen in the device, and the operating conditions were optimized to suit for the large-scale enclosed micro-algae cultivation. Based on the effectiveness evaluation of the HPTD applied in one enclosed flat plate Spirulina culture system, it was confirmed that the HPTD can satisfy the demand of the enclosed system for carbon supplement and excessive oxygen removal.

Uncertainty analysis of the simulations of effects of discharging treated wastewater to the Red River of the North at Fargo, North Dakota, and Moorhead, Minnesota

USGS Publications Warehouse

Wesolowski, Edwin A.

1996-01-01

Two separate studies to simulate the effects of discharging treated wastewater to the Red River of the North at Fargo, North Dakota, and Moorhead, Minnesota, have been completed. In the first study, the Red River at Fargo Water-Quality Model was calibrated and verified for icefree conditions. In the second study, the Red River at Fargo Ice-Cover Water-Quality Model was verified for ice-cover conditions.To better understand and apply the Red River at Fargo Water-Quality Model and the Red River at Fargo Ice-Cover Water-Quality Model, the uncertainty associated with simulated constituent concentrations and property values was analyzed and quantified using the Enhanced Stream Water Quality Model-Uncertainty Analysis. The Monte Carlo simulation and first-order error analysis methods were used to analyze the uncertainty in simulated values for six constituents and properties at sites 5, 10, and 14 (upstream to downstream order). The constituents and properties analyzed for uncertainty are specific conductance, total organic nitrogen (reported as nitrogen), total ammonia (reported as nitrogen), total nitrite plus nitrate (reported as nitrogen), 5-day carbonaceous biochemical oxygen demand for ice-cover conditions and ultimate carbonaceous biochemical oxygen demand for ice-free conditions, and dissolved oxygen. Results are given in detail for both the ice-cover and ice-free conditions for specific conductance, total ammonia, and dissolved oxygen.The sensitivity and uncertainty of the simulated constituent concentrations and property values to input variables differ substantially between ice-cover and ice-free conditions. During ice-cover conditions, simulated specific-conductance values are most sensitive to the headwatersource specific-conductance values upstream of site 10 and the point-source specific-conductance values downstream of site 10. These headwater-source and point-source specific-conductance values also are the key sources of uncertainty. Simulated total ammonia concentrations are most sensitive to the point-source total ammonia concentrations at all three sites. Other input variables that contribute substantially to the variability of simulated total ammonia concentrations are the headwater-source total ammonia and the instream reaction coefficient for biological decay of total ammonia to total nitrite. Simulated dissolved-oxygen concentrations at all three sites are most sensitive to headwater-source dissolved-oxygen concentration. This input variable is the key source of variability for simulated dissolved-oxygen concentrations at sites 5 and 10. Headwatersource and point-source dissolved-oxygen concentrations are the key sources of variability for simulated dissolved-oxygen concentrations at site 14.During ice-free conditions, simulated specific-conductance values at all three sites are most sensitive to the headwater-source specific-conductance values. Headwater-source specificconductance values also are the key source of uncertainty. The input variables to which total ammonia and dissolved oxygen are most sensitive vary from site to site and may or may not correspond to the input variables that contribute the most to the variability. The input variables that contribute the most to the variability of simulated total ammonia concentrations are pointsource total ammonia, instream reaction coefficient for biological decay of total ammonia to total nitrite, and Manning's roughness coefficient. The input variables that contribute the most to the variability of simulated dissolved-oxygen concentrations are reaeration rate, sediment oxygen demand rate, and headwater-source algae as chlorophyll a.

Electrochemical Reduction of Dissolved Oxygen in Alkaline, Solid Polymer Electrolyte Films.

PubMed

Novitski, David; Kosakian, Aslan; Weissbach, Thomas; Secanell, Marc; Holdcroft, Steven

2016-11-30

Mass transport of oxygen through an ionomer contained within the cathode catalyst layer in an anion exchange membrane fuel cell is critical for a functioning fuel cell, yet is relatively unexplored. Moreover, because water is a reactant in the oxygen reduction reaction (ORR) in alkaline media, an adequate supply of water is required. In this work, ORR mass transport behavior is reported for methylated hexamethyl-p-terphenyl polymethylbenzimidazoles (HMT-PMBI), charge balanced by hydroxide ions (IEC from 2.1 to 2.5 mequiv/g), and commercial Fumatec FAA-3 membranes. Electrochemical mass transport parameters are determined by potential step chronoamperometry using a Pt microdisk solid-state electrochemical cell, in air at 60 °C, with relative humidity controlled between 70% and 98%. The oxygen diffusion coefficient (D bO2 ), oxygen concentration (c bO2 ), and oxygen permeability (D bO2 ·c bO2 ) were obtained by nonlinear curve fitting of the current transients using the Shoup-Szabo equation. Mass transport parameters are correlated to water content of the ionomer membrane. It is found that the oxygen diffusion coefficients decreased by 2 orders of magnitude upon reducing the water content of the ionomer membrane by lowering the relative humidity. The limitation of the Shoup-Szabo equation for extracting ORR mass transport parameters using thin ionomer films was evaluated by numerical modeling of the current transients, which revealed that a significant discrepancy (up to 29% under present conditions) was evident for highly hydrated membranes for which the oxygen diffusion coefficient was largest, and in which the oxygen depletion region reached the ionomer/gas interface during the chronoamperometric analysis.

Hydrologic and geochemical effects on oxygen uptake in bottom sediments of an effluent-dominated river

USGS Publications Warehouse

McMahon, P.B.; Tindall, J.A.; Collins, J.A.; Lull, K.J.; Nuttle, J.R.

1995-01-01

More than 95% of the water in the South Platte River downstream from the largest wastewater treatment plant serving the metropolitan Denver, Colorado, area consists of treated effluent during some periods of low flow. Fluctuations in effluent-discharge rates caused daily changes in river stage that promoted exchange of water between the river and bottom sediments. Groundwater discharge measurements indicated fluxes of water across the sediment-water interface as high as 18 m3 s−1 km−1. Laboratory experiments indicated that downward movement of surface water through bottom sediments at velocities comparable to those measured in the field (median rate ≈0.005 cm s−1) substantially increased dissolved oxygen uptake rates in bottom sediments (maximum rate 212 ± 10 μmol O2 L−1 h−1) compared with rates obtained when no vertical advective flux was generated (maximum rate 25 ± 8.8 μmol O2 L−1 h−1). Additions of dissolved ammonium to surface waters generally increased dissolved oxygen uptake rates relative to rates measured in experiments without ammonium. However, the magnitude of the advective flux through bottom sediments had a greater effect on dissolved oxygen uptake rates than did the availability of ammonium. Results from this study indicated that efforts to improve dissolved oxygen dynamics in effluent-dominated rivers might include stabilizing daily fluctuations in river stage.

Role of dissolved oxygen on the degradation mechanism of Reactive Green 19 and electricity generation in photocatalytic fuel cell.

PubMed

Lee, Sin-Li; Ho, Li-Ngee; Ong, Soon-An; Wong, Yee-Shian; Voon, Chun-Hong; Khalik, Wan Fadhilah; Yusoff, Nik Athirah; Nordin, Noradiba

2018-03-01

In this study, a membraneless photocatalytic fuel cell with zinc oxide loaded carbon photoanode and platinum loaded carbon cathode was constructed to investigate the impact of dissolved oxygen on the mechanism of dye degradation and electricity generation of photocatalytic fuel cell. The photocatalytic fuel cell with high and low aeration rate, no aeration and nitrogen purged were investigated, respectively. The degradation rate of diazo dye Reactive Green 19 and the electricity generation was enhanced in photocatalytic fuel cell with higher dissolved oxygen concentration. However, the photocatalytic fuel cell was still able to perform 37% of decolorization in a slow rate (k = 0.033 h -1 ) under extremely low dissolved oxygen concentration (approximately 0.2 mg L -1 ) when nitrogen gas was introduced into the fuel cell throughout the 8 h. However, the change of the UV-Vis spectrum indicates that the intermediates of the dye could not be mineralized under insufficient dissolved oxygen level. In the aspect of electricity generation, the maximum short circuit current (0.0041 mA cm -2 ) and power density (0.00028 mW cm -2 ) of the air purged photocatalytic fuel cell was obviously higher than that with nitrogen purging (0.0015 mA cm -2 and 0.00008 mW cm -2 ). Copyright © 2017 Elsevier Ltd. All rights reserved.

Relationships between wintering waterbirds and invertebrates, sediments and hydrology of coastal marsh ponds

USGS Publications Warehouse

Bolduc, F.; Afton, A.D.

2004-01-01

We studied relationships among sediment variables (carbon content, C:N, hardness, oxygen penetration, silt-clay fraction), hydrologic variables (dissolved oxygen, salinity, temperature, transparency, water depth), sizes and biomass of common invertebrate classes, and densities of 15 common waterbird species in ponds of impounded freshwater, oligohaline, mesohaline, and unimpounded mesohaline marshes during winters 1997-98 to 1999-2000 on Rockefeller State Wildlife Refuge, Louisiana, USA. Canonical correspondence analysis and forward selection was used to analyze the above variables. Water depth and oxygen penetration were the variables that best segregated habitat characteristics that resulted in maximum densities of common waterbird species. Most common waterbird species were associated with specific marsh types, except Green-winged Teal (Anas crecca) and Northern Shoveler (Anas clypeata). We concluded that hydrologic manipulation of marsh ponds is the best way to manage habitats for these birds, if the hydrology can be controlled adequately.

The gut microenvironment of sediment-dwelling Chironomus plumosus larvae as characterised with O2, pH, and redox microsensors.

PubMed

Stief, Peter; Eller, Gundula

2006-09-01

We devised a set-up in which microsensors can be used for characterising the gut microenvironment of aquatic macrofauna. In a small flow cell, we measured microscale gradients through dissected guts (O(2), pH, redox potential [E ( h )]), in the haemolymph (O(2)), and towards the body surface (O(2)) of Chironomus plumosus larvae. The gut microenvironment was compared with the chemical conditions in the lake sediment in which the animals reside and feed. When the dissected guts were incubated at the same nominal O(2) concentration as in haemolymph, the gut content was completely anoxic and had pH and E ( h ) values slightly lower than in the ambient sediment. When the dissected guts were artificially oxygenated, the volumetric O(2)-consumption rates of the gut content were at least 10x higher than in the sediment. Using these potential O(2)-consumption rates in a cylindrical diffusion-reaction model, it was predicted that diffusion of O(2) from the haemolymph to the gut could not oxygenate the gut content under in vivo conditions. Additionally, the potential O(2)-consumption rates were so high that the intake of dissolved O(2) along with feeding could be ruled out to oxygenate the gut content. We conclude that microorganisms present in the gut of C. plumosus cannot exhibit an aerobic metabolism. The presented microsensor technique and the data analysis are applicable to guts of other macrofauna species with cutaneous respiration.

Bulk Dissolution Rates of Cadmium and Bismuth Tellurides As a Function of pH, Temperature and Dissolved Oxygen.

PubMed

Biver, Marc; Filella, Montserrat

2016-05-03

The toxicity of Cd being well established and that of Te suspected, the bulk, surface-normalized steady-state dissolution rates of two industrially important binary tellurides-polycrystalline cadmium and bismuth tellurides- were studied over the pH range 3-11, at various temperatures (25-70 °C) and dissolved oxygen concentrations (0-100% O2 in the gas phase). The behavior of both tellurides is strikingly different. The dissolution rates of CdTe monotonically decreased with increasing pH, the trend becoming more pronounced with increasing temperature. Activation energies were of the order of magnitude associated with surface controlled processes; they decreased with decreasing acidity. At pH 7, the CdTe dissolution rate increased linearly with dissolved oxygen. In anoxic solution, CdTe dissolved at a finite rate. In contrast, the dissolution rate of Bi2Te3 passed through a minimum at pH 5.3. The activation energy had a maximum in the rate minimum at pH 5.3 and fell below the threshold for diffusion control at pH 11. No oxygen dependence was detected. Bi2Te3 dissolves much more slowly than CdTe; from one to more than 3.5 orders of magnitude in the Bi2Te3 rate minimum. Both will readily dissolve under long-term landfill deposition conditions but comparatively slowly.

The vertical structure of upper ocean variability at the Porcupine Abyssal Plain during 2012-2013

NASA Astrophysics Data System (ADS)

Damerell, Gillian M.; Heywood, Karen J.; Thompson, Andrew F.; Binetti, Umberto; Kaiser, Jan

2016-05-01

This study presents the characterization of variability in temperature, salinity and oxygen concentration, including the vertical structure of the variability, in the upper 1000 m of the ocean over a full year in the northeast Atlantic. Continuously profiling ocean gliders with vertical resolution between 0.5 and 1 m provide more information on temporal variability throughout the water column than time series from moorings with sensors at a limited number of fixed depths. The heat, salt and dissolved oxygen content are quantified at each depth. While the near surface heat content is consistent with the net surface heat flux, heat content of the deeper layers is driven by gyre-scale water mass changes. Below ˜150m, heat and salt content display intraseasonal variability which has not been resolved by previous studies. A mode-1 baroclinic internal tide is detected as a peak in the power spectra of water mass properties. The depth of minimum variability is at ˜415m for both temperature and salinity, but this is a depth of high variability for oxygen concentration. The deep variability is dominated by the intermittent appearance of Mediterranean Water, which shows evidence of filamentation. Susceptibility to salt fingering occurs throughout much of the water column for much of the year. Between about 700-900 m, the water column is susceptible to diffusive layering, particularly when Mediterranean Water is present. This unique ability to resolve both high vertical and temporal variability highlights the importance of intraseasonal variability in upper ocean heat and salt content, variations that may be aliased by traditional observing techniques.

New Insights into How Increases in Fertility Improve the Growth of Rice at the Seedling Stage in Red Soil Regions of Subtropical China

PubMed Central

Li, Yilin; Shi, Weiming; Wang, Xingxiang

2014-01-01

The differences in rhizosphere nitrification activities between high- and low- fertility soils appear to be related to differences in dissolved oxygen concentrations in the soil, implying a relationship to differences in the radial oxygen loss (ROL) of rice roots in these soils. A miniaturised Clark-type oxygen microelectrode system was used to determine rice root ROL and the rhizosphere oxygen profile, and rhizosphere nitrification activity was studied using a short-term nitrification activity assay. Rice planting significantly altered the oxygen cycling in the water-soil system due to rice root ROL. Although the oxygen content in control high-fertility soil (without rice plants) was lower than that in control low-fertility soil, high rice root ROL significantly improved the rhizosphere oxygen concentration in the high-fertility soil. High soil fertility improved the rice root growth and root porosity as well as rice root ROL, resulting in enhanced rhizosphere nitrification. High fertility also increased the content of nitrification-induced nitrate in the rhizosphere, resulting in enhanced ammonium uptake and assimilation in the rice. Although high ammonium pools in the high-fertility soil increased rhizosphere nitrification, rice root ROL might also contribute to rhizosphere nitrification improvement. This study provides new insights into the reasons that an increase in soil fertility may enhance the growth of rice. Our results suggest that an amendment of the fertiliser used in nutrient- and nitrification-poor paddy soils in the red soil regions of China may significantly promote rice growth and rice N nutrition. PMID:25291182

Electron efficiency of nZVI does not change with variation of environmental parameters.

PubMed

Schöftner, Philipp; Waldner, Georg; Lottermoser, Werner; Stöger-Pollach, Michael; Freitag, Peter; Reichenauer, Thomas G

2015-12-01

Nanoscale zero-valent iron particles (nZVI) are already applied for in-situ dechlorination of halogenated organic contaminants in the field. We performed batch experiments whereby trichloroethene (TCE) was dehalogenated by nZVI under different environmental conditions that are relevant in practice. The tested conditions include different ionic strengths, addition of polyelectrolytes (carboxymethylcellulose and ligninsulphonate), lowered temperature, dissolved oxygen and different particle contents. Particle properties were determined by Mössbauer spectroscopy, XRD, TEM, SEM, AAS and laser obscuration time measurements. TCE dehalogenation and H2 evolution were decelerated by reduced ionic strength, addition of polyelectrolytes, temperature reduction, the presence of dissolved oxygen and reduced particle content. The partitioning of released electrons between reactions with the contaminant vs. with water (selectivity) was low, independent of the tested conditions. Basically out of hundred electrons that were released via nZVI oxidation only 3.1±1.4 were used for TCE dehalogenation. Even lower selectivities were observed at TCE concentrations below 3.5 mg l(-1), hence particle modifications and/or combination of nZVI with other remediation technologies seem to be necessary to reach target concentrations for remediation. Our results suggest that selectivity is particle intrinsic and not as much condition dependent, hence particle synthesis and potential particle modifications of nZVI particles may be more important for optimization of the pollutant degradation rate, than tested environmental conditions. Copyright © 2015 Elsevier B.V. All rights reserved.

ACUTE SENSITIVITY OF JUVENILE SHORTNOSE STURGEON TO LOW DISSOLVED OXYGEN CONCENTRATIONS

EPA Science Inventory

Campbell, Jed G. and Larry R. Goodman. 2004. Acute Sensitivity of Juvenile Shortnose Sturgeon to Low Dissolved Oxygen Concentrations. EPA/600/J-04/175. Trans. Am. Fish. Soc. 133(3):772-776. (ERL,GB 1155).

There is considerable concern that factors such as eutrophication, ...

Dissolved oxygen in two Oregon estuaries: Importance of the ocean-estuary connection

EPA Science Inventory

We examined the role of the ocean –estuary connection in influencing periodic reductions in dissolved oxygen (DO) levels in Yaquina and Yachats estuaries, Oregon, USA. In the Yaquina Estuary, there is close coupling between the coastal ocean and the estuary. As a result, low DO ...

Pilot Plant Demonstration of Stable and Efficient High Rate Biological Nutrient Removal with Low Dissolved Oxygen Conditions

EPA Science Inventory

Aeration in biological nutrient removal (BNR) processes accounts for nearly half of the total electricity costs at many wastewater treatment plants. Even though conventional BNR processes are usually operated to have aerated zones with high dissolved oxygen (DO) concentrations, r...

Dissolved oxygen in two Oregon estuaries: The importance of the ocean-estuary connection

EPA Science Inventory

We examined the role of the ocean –estuary connection in influencing periodic reductions in dissolved oxygen (DO) levels in Yaquina and Yachats estuaries, Oregon, USA. In the Yaquina Estuary, there is close coupling between the coastal ocean and the estuary. As a result, low DO ...

A Simplified and Inexpensive Method for Measuring Dissolved Oxygen in Water.

ERIC Educational Resources Information Center

Austin, John

1983-01-01

A modified Winkler method for determining dissolved oxygen in water is described. The method does not require use of a burette or starch indicator, is simple and inexpensive and can be used in the field or laboratory. Reagents/apparatus needed and specific procedures are included. (JN)

PHOTOGENERATION OF SINGLET OXYGEN AND FREE RADICALS IN DISSOLVED ORGANIC MATTER ISOLATED FROM THE MISSISSIPPI AND ATCHAFALAYA RIVER PLUMES

EPA Science Inventory

The photoreactivity to UV light of ultrafiltered dissolved organic matter (DOM) collected during cruises along salinity transects in the Mississippi and Atchafalaya River plumes was examined by measuring photogenerated free radicals and singlet molecular oxygen (1O2) photosensiti...

RESEARCH AT THE GULF ECOLOGY DIVISION ON THE EFFECTS OF LOW DISSOLVED OXYGEN ON ESTUARINE ANIMALS

EPA Science Inventory

Concerns about hypoxia and its effects on saltwater organisms are increasing as environmental conditions in the inshore and nearshore marine environments are better understood. Along the Gulf of Mexico coast, periods of very low dissolved oxygen (D.O.) concentrations have been re...

Biodegradation of the surfactant linear alkylbenzenesulfonate in sewage- contaminated groundwater: A comparison of column experiments and field tracer tests

USGS Publications Warehouse

Krueger, C.J.; Radakovich, K.M.; Sawyer, T.E.; Barber, L.B.; Smith, R.L.; Field, J.A.

1998-01-01

Transport and biodegradation of linear alkylbenzenesulfonate (LAS) in sewage-contaminated groundwater were investigated for a range of dissolved oxygen concentrations. Both laboratory column and an 80-day continuous injection tracer test field experiments were conducted. The rates of LAS biodegradation increased with increasing dissolved oxygen concentrations and indicated the preferential biodegradation of the longer alkyl chain LAS homologues (i.e., C12 and C13) and external isomers (i.e., 2-and 3- phenyl). However, for similar dissolved oxygen concentrations, mass removal rates for LAS generally were 2-3 times greater in laboratory column experiments than in the field tracer test. Under low oxygen conditions (<1 mg/L) only a fraction of the LAS mixture biodegraded in both laboratory and field experiments. Biodegradation rate constants for the continuous injection field test (0.002-0.08 day-1) were comparable to those estimated for a 3-h injection (pulsed) tracer test conducted under similar biogeochemical conditions, indicating that increasing the exposure time of aquifer sediments to LAS did not increase biodegradation rates.Transport and biodegradation of linear alkylbenzenesulfonate (LAS) in sewage-contaminated groundwater were investigated for a range of dissolved oxygen concentrations. Both laboratory column and an 80-day continuous injection tracer test field experiments were conducted. The rates of LAS biodegradation increased with increasing dissolved oxygen concentrations and indicated the preferential biodegradation of the longer alkyl chain LAS homologues (i.e., C12 and C13) and external isomers (i.e., 2- and 3-phenyl). However, for similar dissolved oxygen concentrations, mass removal rates for LAS generally were 2-3 times greater in laboratory column experiments than in the field tracer test. Under low oxygen conditions (<1 mg/L) only a fraction of the LAS mixture biodegraded in both laboratory and field experiments. Biodegradation rate constants for the continuous injection field test (0.002-0.08 day-1) were comparable to those estimated for a 3-h injection (pulsed) tracer test conducted under similar biogeochemical conditions, indicating that increasing the exposure time of aquifer sediments to LAS did not increase biodegradation rates.

A water-quality reconnaissance of Big Bear Lake, San Bernardino County, California, 1972-1973

USGS Publications Warehouse

Irwin, George A.; Lemons, Michael

1974-01-01

A water-quality reconnaissance study of the Big Bear Lake area in southern California was made by the U.S. Geological Survey from April 1972 through April 1973. The primary purpose of the study was to measure the concentration and distribution of selected primary nutrients, organic carbon, dissolved oxygen, phytoplankton, and water temperature in the lake. Estimates of the nitrogen, phosphorus, and silica loading to the lake from surface-water tributaries and precipitation were also made.Results of the study indicate that Big Bear Lake is moderately eutrophic, at least in regard to nitrogen, phosphorus, and organic content. Nitrate was found in either trace concentrations or below detectable limits; however, ammonia nitrogen was usually detected in concentrations greater than 0.05 milligrams per liter. Orthophosphate phosphorus was detected in mean concentrations ranging from 0.01 to 0.05 milligrams per liter. Organic nitrogen and phosphorus were also detected in measurable concentrations.Seasonal levels of dissolved oxygen indicated that the nutrients and other controlling factors were optimum for relatively high primary productivity. However, production varied both seasonally and areally in the lake. Primary productivity seemed highest in the eastern and middle parts of the lake. The middle and western parts of the lake exhibited severe oxygen deficits in the deeper water during the warmer summer months of June and July 1972.

Temperature-dependent endogenous oxygen concentration regulates microsomal oleate desaturase in developing sunflower seeds.

PubMed

Rolletschek, Hardy; Borisjuk, Ljudmilla; Sánchez-García, Alicia; Gotor, Cecilia; Romero, Luis C; Martínez-Rivas, José M; Mancha, Manuel

2007-01-01

Oleoyl-phosphatidylcholine desaturase (FAD2) is a key enzyme involved in fatty acid desaturation in oilseeds, which is affected by environmental temperature. The results of this study show that FAD2 is regulated in vivo via temperature-dependent endogenous oxygen concentrations in developing sunflower (Helianthus annuus L.) seeds. By combining in vivo oxygen profiling, in situ hybridization of FAD2 genes, an assay of energy status, fatty acid analysis, and an in vitro FAD2 enzyme activity assay, it is shown that: (i) the oil-storing embryo is characterized by a very low oxygen level that is developmentally regulated. Oxygen supply is mainly limited by the thin seed coat. (ii) Elevations of external oxygen supply raised the energy status of seed and produced a dramatic increase of the FAD2 enzyme activity as well as the linoleic acid content. (iii) A clear negative correlation exists between temperature and internal oxygen concentration. The changes occurred almost instantly and the effect was fully reversible. The results indicate that the internal oxygen level acts as a key regulator for the activity of the FAD2 enzyme. It is concluded that a major mechanism by which temperature modifies the unsaturation degree of the sunflower oil is through its effect on dissolved oxygen levels in the developing seed.

A one-dimensional, steady-state, dissolved-oxygen model and waste-load assimilation study for Silver Creek, Clark and Floyd counties, Indiana

USGS Publications Warehouse

Wilber, William G.; Crawford, Charles G.; Peters, James G.

1979-01-01

The Indiana State Board of Health is developing a State water-quality management plan that includes establishing limits for wastewater effluents discharged into Indiana streams. A digital model calibrated to conditions in Silver Creek was used to develop alternatives for future waste loadings that would be compatible with Indiana stream water-quality standards defined for two critical hydrologic conditions, summer and winter low flows. Effluents from the Sellersburg and Clarksville-North wastewater-treatment facilities are the only point-source waste loads that significantly affect the water quality in the modeled segment of Silver Creek. Model simulations indicate that nitrification is the most significant factor affecting the dissolved-oxygen concentration in Silver Creek during summer and winter low flows. Natural streamflow in Silver Creek during the summer and annual 7-day, 10-year low flow is zero, so no benefit from dilution is provided. Present ammonia-nitrogen and dissolved-oxygen concentrations of effluent from the Sellersburg and Clarksville-North wastewater-treatment facilities will violate current Indiana water-quality standards for ammonia toxicity and dissolved oxygen during summer and winter low flows. The current biochemical-oxygen demand limits for the Sellersburg and Clarksville-North wastewater-treatment facilities are not sufficient to maintain an average dissolved-oxygen concentration of at least 5 milligrams per liter, the State 's water-quality standard for streams. Calculations of the stream 's assimilative capacity indicate that Silver Creek cannot assimilate additional waste loadings and meet current Indiana water-quality standards. (Kosco-USGS)

Water-quality data for Smith and Bybee Lakes, Portland, Oregon, June to November, 1982

USGS Publications Warehouse

Clifton, Daphne G.

1983-01-01

Water-quality monitoring at Smith and Bybee Lakes included measurement of water temperature, dissolved oxygen concentration and percent saturation, pH, specific conductance, lake depth, alkalinity, dissolved carbon, total dissolved solids, secchi disk light transparency, nutrients, and chlorophyll a and b. In addition, phytoplankton, zooplankton, and benthic invertebrate populations were identified and enumerated. Lakebed sediment was analyzed for particle size, volatile solids, immediate oxygen demand, trace metals, total organic carbon, nutrients, and organic constituents. (USGS)

A bench-scale assessment for phosphorus release control of sediment by an oxygen-releasing compound (ORC).

PubMed

Yang, Jie; Lin, Feng K; Yang, Lei; Hua, Dan Y

2015-01-01

The effects of oxygen-releasing compound (ORC) on the control of phosphorus (P) release as well as the spatial and temporal distribution of P fractions in sediment were studied through a bench-scale test. An ORC with an extended oxygen-releasing capacity was prepared. The results of the oxygen-releasing test showed that the ORC provided a prolonged period of oxygen release with a highly effective oxygen content of 60.6% when compared with powdery CaO2. In the bench-scale test, an ORC dose of 180 g·m(-2) provided a higher inhibition efficiency for P release within 50 days. With the application of the ORC, the dissolved oxygen (DO) concentration and redox potential (ORP) of the overlying water were notably improved, and the dissolved total phosphorus (DTP) was maintained below 0.689 mg·L(-1) compared to 2.906 mg·L(-1) without the ORC treatment. According to the P fractions distribution, the summation of all detectable P fractions in each sediment layer exhibited an enhanced accumulation tendency with the application of ORC. Higher phosphorus retention efficiencies were observed in the second and third layers of sediment from days 10 to 20 with the ORC. Phosphorus was trapped mainly in the form of iron bound P (Fe-P) and organically bound P (O-P) in sediment with the ORC, whereas the effects of the ORC on exchangeable P (EX-P), apatite-associated P (A-P) and detrital P (De-P) in the sediment sample were not significant. The microbial activities of the sediment samples demonstrated that both the dehydrogenase activity (DHA) and alkaline phosphatase activity (APA) in the upper sediment layer increased with the ORC treatment, which indicated that the mineralization of P was accelerated and the microbial biomass was increased. As the accumulation of P suppressed the release of P, the sediment exhibited an increased P retention efficiency with the application of the ORC.

Effect of Dissolved Oxygen on the Filterability of Jet Fuels for Temperatures Between 300 Degrees and 400 Degrees F

NASA Technical Reports Server (NTRS)

Mckeown, Anderson B; Hibbard, Robert R

1955-01-01

The effect of dissolved oxygen in the filter-clogging characteristics of three JP-4 and two JP-5 fuels was studied at 300 degrees to 400 degrees F in a bench- scale rig, employing filter paper as the filter medium. The residence time of the fuel at the high temperature was approximately 6 seconds. For these conditions, the clogging characteristics of the fuels increased with both increasing temperature and increasing concentration of dissolved oxygen. The amount of insoluble material formed at high temperatures necessary to produce clogging of filters was very small, of the order of 1 milligram per gallon of fuel.

Long-term groundwater contamination after source removal—The role of sorbed carbon and nitrogen on the rate of reoxygenation of a treated-wastewater plume on Cape Cod, MA, USA

USGS Publications Warehouse

Smith, Richard L.; Repert, Deborah A.; Barber, Larry B.; LeBlanc, Denis R.

2013-01-01

The consequences of groundwater contamination can remain long after a contaminant source has been removed. Documentation of natural aquifer recoveries and empirical tools to predict recovery time frames and associated geochemical changes are generally lacking. This study characterized the long-term natural attenuation of a groundwater contaminant plume in a sand and gravel aquifer on Cape Cod, Massachusetts, after the removal of the treated-wastewater source. Although concentrations of dissolved organic carbon (DOC) and other soluble constituents have decreased substantially in the 15 years since the source was removed, the core of the plume remains anoxic and has sharp redox gradients and elevated concentrations of nitrate and ammonium. Aquifer sediment was collected from near the former disposal site at several points in time and space along a 0.5-km-long transect extending downgradient from the disposal site and analyses of the sediment was correlated with changes in plume composition. Total sediment carbon content was generally low (< 8 to 55.8 μmol (g dry wt)− 1) but was positively correlated with oxygen consumption rates in laboratory incubations, which ranged from 11.6 to 44.7 nmol (g dry wt)− 1 day− 1. Total water extractable organic carbon was < 10–50% of the total carbon content but was the most biodegradable portion of the carbon pool. Carbon/nitrogen (C/N) ratios in the extracts increased more than 10-fold with time, suggesting that organic carbon degradation and oxygen consumption could become N-limited as the sorbed C and dissolved inorganic nitrogen (DIN) pools produced by the degradation separate with time by differential transport. A 1-D model using total degradable organic carbon values was constructed to simulate oxygen consumption and transport and calibrated by using observed temporal changes in oxygen concentrations at selected wells. The simulated travel velocity of the oxygen gradient was 5–13% of the groundwater velocity. This suggests that the total sorbed carbon pool is large relative to the rate of oxygen entrainment and will be impacting groundwater geochemistry for many decades. This has implications for long-term oxidation of reduced constituents, such as ammonium, that are being transported downgradient away from the infiltration beds toward surface and coastal discharge zones.

Quality changes in sea urchin (Strongylocentrotus nudus) during storage in artificial seawater saturated with oxygen, nitrogen and air.

PubMed

Wang, Chao; Xue, Changhu; Xue, Yong; Li, Zhaojie; Lv, Yingchun; Zhang, Hao

2012-01-15

Sea urchin gonads are highly valued seafood that degenerates rapidly during the storage period. To study the influence of dissolved oxygen concentration on quality changes of sea urchin (Strongylocentrotus nudus) gonads, they were stored in artificial seawater saturated with oxygen, nitrogen or air at 5 ± 1 °C for 12 days. The sensory acceptability limit was 11-12, 6-7 and 7-8 days for gonads with oxygen, nitrogen or air packaging, respectively. Total volatile basic nitrogen (TVB-N) values reached 22.60 ± 1.32, 32.37 ± 1.37 and 24.91 ± 1.54 mg 100 g(-1) for gonads with oxygen, nitrogen or air packaging at the points of near to, exceeding and reaching the limit of sensory acceptability, indicating that TVB-N values of about 25 mg 100 g(-1) should be regarded as the limit of acceptability for sea urchin gonads. Relative ATP content values were 56.55%, 17.36% and 18.75% for gonads with oxygen, nitrogen or air packaging, respectively, on day 2. K-values were 19.37%, 25.05% and 29.02% for gonads with oxygen, nitrogen or air packaging, respectively, on day 2. Both pH and aerobic plate count values showed no significant difference (P > 0.05) for gonads with the three treatments. Gonads with oxygen packaging had lower sensory demerit point (P < 0.05) and TVB-N values (P < 0.05), and higher relative ATP content (P < 0.01) and K-values (P < 0.05), than that with nitrogen or air packaging, with an extended shelf life of 4-5 days during storage in artificial seawater at 5 ± 1 °C. Copyright © 2011 Society of Chemical Industry.

Oxidation of hydrogen sulfide in biogas using dissolved oxygen in the extreme acidic biofiltration operation.

PubMed

Charnnok, Boonya; Suksaroj, Thunwadee; Boonswang, Piyarat; Chaiprapat, Sumate

2013-03-01

This work aimed to investigate the interactive effects of empty bed retention time (EBRT), specific hydraulic loading rate (q) and initial pH (pHi) of the aerated recirculating liquid to remove H2S in extreme acidic biofiltration. Biogas containing H2S 6395±2309ppm and CH4 79.8±2.5% was fed to the biofilter as pH of the high dissolved oxygen recirculating liquid swung between pHi to 0.5. Response surface methodology was employed that gave the H2S removal relationship model with R(2) 0.882. The predicted highest H2S removal within the studied parameter ranges was 94.7% at EBRT 180.0s, q 4.0m(3)/m(2)/h and pHi 3.99. Results from separate runs at a random condition were not statistically different from the model prediction, signifying a validity of the model. Additionally, CH4 content in the exit biogas increased by 4.7±0.4%. Acidithiobacullus sp. predominance in the consortia of this extreme acidic condition was confirmed by DGGE. Copyright © 2012 Elsevier Ltd. All rights reserved.

Layer-by-layer carbon nanotube bio-templates for in situ monitoring of the metabolic activity of nitrifying bacteria

NASA Astrophysics Data System (ADS)

Loh, Kenneth J.; Guest, Jeremy S.; Ho, Genevieve; Lynch, Jerome P.; Love, Nancy G.

2009-03-01

Despite the wide variety of effective disinfection and wastewater treatment techniques for removing organic and inorganic wastes, pollutants such as nitrogen remain in wastewater effluents. If left untreated, these nitrogenous wastes can adversely impact the environment by promoting the overgrowth of aquatic plants, depleting dissolved oxygen, and causing eutrophication. Although nitrification/denitrification processes are employed during advanced wastewater treatment, effective and efficient operation of these facilities require information of the pH, dissolved oxygen content, among many other parameters, of the wastewater effluent. In this preliminary study, a biocompatible CNT-based nanocomposite is proposed and validated for monitoring the biological metabolic activity of nitrifying bacteria in wastewater effluent environments (i.e., to monitor the nitrification process). Using carbon nanotubes and a pH-sensitive conductive polymer (i.e., poly(aniline) emeraldine base), a layer-by-layer fabrication technique is employed to fabricate a novel thin film pH sensor that changes its electrical properties in response to variations in ambient pH environments. Laboratory studies are conducted to evaluate the proposed nanocomposite's biocompatibility with wastewater effluent environments and its pH sensing performance.

Improving estimates of ecosystem metabolism by reducing effects of tidal advection on dissolved oxygen time series

EPA Science Inventory

In aquatic systems, time series of dissolved oxygen (DO) have been used to compute estimates of ecosystem metabolism. Central to this open-water method is the assumption that the DO time series is a Lagrangian specification of the flow field. However, most DO time series are coll...

Dissolved oxygen in two Oregon estuaries: Importance of the ocean-estuary connection - March 2011

EPA Science Inventory

We examined the role of the ocean–estuary connection in influencing periodic reductions in dissolved oxygen (DO) levels in Yaquina and Yachats estuaries, Oregon, USA. In the Yaquina Estuary, there is close coupling between the coastal ocean and the estuary. As a result, low DO w...

Application of a one-dimensional model to explore the drivers and lability of carbon in the northern Gulf of Mexico

EPA Science Inventory

A one-dimensional water quality model, Gulf of Mexico Dissolved Oxygen Model (GoMDOM-1D), was developed to simulate phytoplankton, carbon, nutrients, and dissolved oxygen in Gulf of Mexico. The model was calibrated and corroborated against a comprehensive set of field observation...

Dissolved oxygen in two Oregon estuaries: The importance of the ocean-estuary connection - May 16, 2011

EPA Science Inventory

We examined the role of the ocean –estuary connection in influencing periodic reductions in dissolved oxygen (DO) levels in Yaquina and Yachats estuaries, Oregon, USA. In the Yaquina Estuary, there is close coupling between the coastal ocean and the estuary. As a result, low DO ...

DETERMINATION OF LETHAL DISSOLVED OXYGEN LEVELS FOR SELECTED MARINE AND ESTUARINE FISHES, CRUSTACEANS AND A BIVALVE

EPA Science Inventory

The objective of this study was to provide a database of the incipient lethal concentrations for reduced dissolved oxygen (DO) for selected marine and estuarine species including 12 species of fish, 9 crustaceans, and 1 bivalve. All species occur in the Virginian Province, USA, w...

Hyperosmotic Agents and Antibiotics Affect Dissolved Oxygen and pH Concentration Gradients in Staphylococcus aureus Biofilms

PubMed Central

Kiamco, Mia Mae; Atci, Erhan

2017-01-01

ABSTRACT Biofilms on wound surfaces are treated topically with hyperosmotic agents, such as medical-grade honey and cadexomer iodine; in some cases, these treatments are combined with antibiotics. Tissue repair requires oxygen, and a low pH is conducive to oxygen release from red blood cells and epithelialization. We investigated the variation of dissolved oxygen concentration and pH with biofilm depth and the variation in oxygen consumption rates when biofilms are challenged with medical-grade honey or cadexomer iodine combined with vancomycin or ciprofloxacin. Dissolved oxygen and pH depth profiles in Staphylococcus aureus biofilms were measured using microelectrodes. The presence of cadexomer iodine with vancomycin or ciprofloxacin on the surface of the biofilm permitted a measurable concentration of oxygen at greater biofilm depths (101.6 ± 27.3 μm, P = 0.02; and 155.5 ± 27.9 μm, P = 0.016, respectively) than in untreated controls (30.1 μm). Decreases in pH of ∼0.6 and ∼0.4 units were observed in biofilms challenged with medical-grade honey alone and combined with ciprofloxacin, respectively (P < 0.001 and 0.01, respectively); the number of bacteria recovered from biofilms was significantly reduced (1.26 log) by treatment with cadexomer iodine and ciprofloxacin (P = 0.002) compared to the untreated control. Combining cadexomer iodine and ciprofloxacin improved dissolved oxygen concentration and penetration depth into the biofilm, while medical-grade honey was associated with a lower pH; not all treatments established a bactericidal effect in the time frame used in the experiments. IMPORTANCE Reports about using hyperosmotic agents and antibiotics against wound biofilms focus mostly on killing bacteria, but the results of these treatments should additionally be considered in the context of how they affect physiologically important parameters, such as oxygen concentration and pH. We confirmed that the combination of a hyperosmotic agent and an antibiotic results in greater dissolved oxygen and reduced pH within an S. aureus biofilm. PMID:28062458

Hyperosmotic Agents and Antibiotics Affect Dissolved Oxygen and pH Concentration Gradients in Staphylococcus aureus Biofilms.

PubMed

Kiamco, Mia Mae; Atci, Erhan; Mohamed, Abdelrhman; Call, Douglas R; Beyenal, Haluk

2017-03-15

Biofilms on wound surfaces are treated topically with hyperosmotic agents, such as medical-grade honey and cadexomer iodine; in some cases, these treatments are combined with antibiotics. Tissue repair requires oxygen, and a low pH is conducive to oxygen release from red blood cells and epithelialization. We investigated the variation of dissolved oxygen concentration and pH with biofilm depth and the variation in oxygen consumption rates when biofilms are challenged with medical-grade honey or cadexomer iodine combined with vancomycin or ciprofloxacin. Dissolved oxygen and pH depth profiles in Staphylococcus aureus biofilms were measured using microelectrodes. The presence of cadexomer iodine with vancomycin or ciprofloxacin on the surface of the biofilm permitted a measurable concentration of oxygen at greater biofilm depths (101.6 ± 27.3 μm, P = 0.02; and 155.5 ± 27.9 μm, P = 0.016, respectively) than in untreated controls (30.1 μm). Decreases in pH of ∼0.6 and ∼0.4 units were observed in biofilms challenged with medical-grade honey alone and combined with ciprofloxacin, respectively ( P < 0.001 and 0.01, respectively); the number of bacteria recovered from biofilms was significantly reduced (1.26 log) by treatment with cadexomer iodine and ciprofloxacin ( P = 0.002) compared to the untreated control. Combining cadexomer iodine and ciprofloxacin improved dissolved oxygen concentration and penetration depth into the biofilm, while medical-grade honey was associated with a lower pH; not all treatments established a bactericidal effect in the time frame used in the experiments. IMPORTANCE Reports about using hyperosmotic agents and antibiotics against wound biofilms focus mostly on killing bacteria, but the results of these treatments should additionally be considered in the context of how they affect physiologically important parameters, such as oxygen concentration and pH. We confirmed that the combination of a hyperosmotic agent and an antibiotic results in greater dissolved oxygen and reduced pH within an S. aureus biofilm. Copyright © 2017 American Society for Microbiology.

High-pressure injection of dissolved oxygen for hydrocarbon remediation in a fractured dolostone aquifer.

PubMed

Greer, K D; Molson, J W; Barker, J F; Thomson, N R; Donaldson, C R

2010-10-21

A field experiment was completed at a fractured dolomite aquifer in southwestern Ontario, Canada, to assess the delivery of supersaturated dissolved oxygen (supersaturated with respect to ambient conditions) for enhanced bioremediation of petroleum hydrocarbons in groundwater. The injection lasted for 1.5h using iTi's gPro® oxygen injection technology at pressures of up to 450 kPa and at concentrations of up to 34 mg O₂/L. A three-dimensional numerical model for advective-dispersive transport of dissolved oxygen within a discretely-fractured porous medium was calibrated to the observed field conditions under a conservative (no-consumption) scenario. The simulation demonstrated that oxygen rapidly filled the local intersecting fractures as well as the porous matrix surrounding the injection well. Following injection, the local fractures were rapidly flushed by the natural groundwater flow system but slow back-diffusion ensured a relatively longer residence time in the matrix. A sensitivity analysis showed significant changes in behaviour with varying fracture apertures and hydraulic gradients. Applying the calibrated model to a 7-day continuous injection scenario showed oxygen residence times (at the 3mg/L limit), within a radius of 2-4m from the injection well, of up to 100 days. This study has demonstrated that supersaturated dissolved oxygen can be effectively delivered to this type of a fractured and porous bedrock system at concentrations and residence times potentially sufficient for enhanced aerobic biodegradation. Copyright © 2010 Elsevier B.V. All rights reserved.

The influence of kinetics on the oxygen isotope composition of calcium carbonate

NASA Astrophysics Data System (ADS)

Watkins, James M.; Nielsen, Laura C.; Ryerson, Frederick J.; DePaolo, Donald J.

2013-08-01

Paleotemperature reconstructions rely on knowledge of the equilibrium separation of oxygen isotopes between aqueous solution and calcium carbonate. Although oxygen isotope separation is expected on theoretical grounds, the temperature-dependence remains uncertain because other factors, such as slow exchange of isotopes between dissolved CO2-species and water, can obscure the temperature signal. This is problematic for crystal growth experiments on laboratory timescales and for interpreting the oxygen isotope composition of crystals formed in natural settings. We present results from experiments in which inorganic calcite is precipitated in the presence of 0.25 μM dissolved bovine carbonic anhydrase (CA). The presence of dissolved CA accelerates oxygen isotope equilibration between the dissolved carbon species CO2, H2CO3, HCO3-, CO32- and water, thereby eliminating this source of isotopic disequilibrium during calcite growth. The experimental results allow us to isolate, for the first time, kinetic oxygen isotope effects occurring at the calcite-water interface. We present a framework of ion-by-ion growth of calcite that reconciles our new measurements with measurements of natural cave calcites that are the best candidate for having precipitated under near-equilibrium conditions. Our findings suggest that isotopic equilibrium between calcite and water is unlikely to have been established in laboratory experiments or in many natural settings. The use of CA in carbonate precipitation experiments offers new opportunities to refine oxygen isotope-based geothermometers and to interrogate environmental variables other than temperature that influence calcite growth rates.

The Effects of Elevated pCO2, Hypoxia and Temperature on ...

EPA Pesticide Factsheets

Estuarine fish are acclimated to living in an environment with rapid and frequent changes in temperature, salinity, pH, and dissolved oxygen (DO) levels; the physiology of these organisms is well suited to cope with extreme thermal, hypercapnic, and hypoxic stress. While the adverse effects of low dissolved oxygen levels on estuarine fish has been well-documented, the interaction between low DO and elevated pCO2 is not well understood. There is some evidence that low DO and elevated pCO2 interact antagonistically, however little information exists on how projected changes of pCO2 levels in near-shore waters may affect estuarine species, and how these changes may specifically interact with dissolved oxygen and temperature. We explored the survivability of 7-day post fertilization sheepshead minnow, Cyprinodon variegatus, using short term exposure to the combined effects of elevated pCO2 (~1300 µatm; IPCC RCP 8.5) and low dissolved oxygen levels (~2 mg/L). Additionally, we determined if the susceptibility of these fish to elevated pCO2 and low DO was influenced by increases in temperature from 27.5°C to 35°C. Results from this study and future studies will be used to identify estuarine species and lifestages sensitive to the combined effects of elevated pCO2 and low dissolved oxygen. This project was created in order to better understand the interactive effects of projected pCO2 levels and hypoxia in estuarine organisms. This work is currently focused on the se

Trophic conditions in Lake Winnisquam, New Hampshire

USGS Publications Warehouse

Frost, Leonard R.

1977-01-01

Lake Winnisquam has received treated domestic sewage for approximately 50 years and since June 1961 has been treated with copper sulfate to control the growth of nuisance algae. The Laconia City secondary sewage-treatment plant was upgraded in 1975 to include phosphorus removal. Phosphorus was not removed effectively until early 1976, and, therefore, the 1976 data are considered baseline or pre-phosphorus removal with respect to anticipated changes in the trophic condition of the lake. Effluent from the Laconia State School primary-treatment plant was diverted to the Laconia City plant in October 1976. Dissolved oxygen concentrations showed marked differences between the two basins comprising Lake Winnisquam. Phytoplankton samples showed similarities by algal group for all stations but algal genera varied between the upper and lower basins. Total phosphorus concentrations in the epilimnion ranged from 0.01 to 0.10 milligram per liter, and accumulation of total phosphorus in the hypolimnion resulted in concentrations up to 0.59 milligrams per liter. Chemical states of nutrients varied among the stations corresponding to the degree of depletion of hypolimnetic dissolved oxygen. Dissolved oxygen profiles were used to illustrate zones of algal production, respiration, and bacterial decomposition. The rate of depletion of dissolved oxygen in the hypolimnion was linearly related to time. Because change in the rate of hypolimnetic dissolved oxygen depletion is more easily measured than change of nutrient load in the lake, it is suggested it be used as an indicator of the response of the lake to change in trophic condition.

δ34S and δ18O of dissolved sulfate as biotic tracer of biogeochemical influences on arsenic mobilization in groundwater in the Hetao Plain, Inner Mongolia, China.

PubMed

Li, M D; Wang, Y X; Li, P; Deng, Y M; Xie, X J

2014-12-01

Environmental isotopology of sulfur and oxygen of dissolved sulfate in groundwater was conducted in the Hetao Plain, northwestern China, aiming to better understand the processes controlling arsenic mobilization in arsenic-rich aqueous systems. A total of 22 groundwater samples were collected from domestic wells in the Hetao Plain. Arsenic concentrations ranged from 11.0 to 388 μg/L. The δ(34)S-SO4 and δ(18)O-SO4 values of dissolved sulfate covered a range from +1.48 to +22.4‰ and +8.17‰ to +14.8‰ in groundwater, respectively. The wide range of δ(34)S-SO4 values reflected either an input of different sources of sulfate, such as gypsum dissolution and fertilizer application, or a modification from biogeochemical process of bacterial sulfate reduction. The positive correlation between δ(34)S-SO4 and arsenic concentrations suggested that bacteria mediated processes played an important role in the mobilization of arsenic. The δ(18)O-SO4 values correlated non-linearly with δ(34)S-SO4, but within a relatively narrow range (+8.17 to +14.8‰), implying that complexities inherent in the sulfate-oxygen (O-SO4(2-)) origins, for instance, water-derived oxygen (O-H2O), molecular oxygen (O-O2) and isotope exchanging with dissolved oxides, are accounted for oxygen isotope composition of dissolved sulfate in groundwater in the Hetao Plain.

Assessment of suspended-sediment transport, bedload, and dissolved oxygen during a short-term drawdown of Fall Creek Lake, Oregon, winter 2012-13

USGS Publications Warehouse

Schenk, Liam N.; Bragg, Heather M.

2014-01-01

The drawdown of Fall Creek Lake resulted in the net transport of approximately 50,300 tons of sediment from the lake during a 6-day drawdown operation, based on computed daily values of suspended-sediment load downstream of Fall Creek Dam and the two main tributaries to Fall Creek Lake. A suspended-sediment budget calculated for 72 days of the study period indicates that as a result of drawdown operations, there was approximately 16,300 tons of sediment deposition within the reaches of Fall Creek and the Middle Fork Willamette River between Fall Creek Dam and the streamgage on the Middle Fork Willamette River at Jasper, Oregon. Bedload samples collected at the station downstream of Fall Creek Dam during the drawdown were primarily composed of medium to fine sands and accounted for an average of 11 percent of the total instantaneous sediment load (also termed sediment discharge) during sample collection. Monitoring of dissolved oxygen at the station downstream of Fall Creek Dam showed an initial decrease in dissolved oxygen concurrent with the sediment release over the span of 5 hours, though the extent of dissolved oxygen depletion is unknown because of extreme and rapid fouling of the probe by the large amount of sediment in transport. Dissolved oxygen returned to background levels downstream of Fall Creek Dam on December 18, 2012, approximately 1 day after the end of the drawdown operation.

Monitoring And Modeling Environmental Water Quality To Support Environmental Water Purchase Decision-making

NASA Astrophysics Data System (ADS)

Null, S. E.; Elmore, L.; Mouzon, N. R.; Wood, J. R.

2016-12-01

More than 25 million cubic meters (20,000 acre feet) of water has been purchased from willing agricultural sellers for environmental flows in Nevada's Walker River to improve riverine habitat and connectivity with downstream Walker Lake. Reduced instream flows limit native fish populations, like Lahontan cutthroat trout, through warm daily stream temperatures and low dissolved oxygen concentrations. Environmental water purchases maintain instream flows, although effects on water quality are more varied. We use multi-year water quality monitoring and physically-based hydrodynamic and water quality modeling to estimate streamflow, water temperature, and dissolved oxygen concentrations with alternative environmental water purchases. We simulate water temperature and dissolved oxygen changes from increased streamflow to prioritize the time periods and locations that environmental water purchases most enhance trout habitat as a function of water quality. Monitoring results indicate stream temperature and dissolved oxygen limitations generally exist in the 115 kilometers upstream of Walker Lake (about 37% of the study area) from approximately May through September, and this reach acts as a water quality barrier for fish passage. Model results indicate that low streamflows generally coincide with critically warm stream temperatures, water quality refugia exist on a tributary of the Walker River, and environmental water purchases may improve stream temperature and dissolved oxygen conditions for some reaches and seasons, especially in dry years and prolonged droughts. This research supports environmental water purchase decision-making and allows water purchase decisions to be prioritized with other river restoration alternatives.

Material and method for promoting the growth of anaerobic bacteria

DOEpatents

Adler, H.I.

1984-10-09

A material and method is disclosed for promoting the growth of anaerobic bacteria which includes a nutrient media containing a hydrogen donor and sterile membrane fragments of bacteria having an electron transfer system which reduces oxygen to water. Dissolved oxygen in the medium is removed by adding the sterile membrane fragments to the nutrient medium and holding the medium at a temperature of about 10 to about 60 C until the dissolved oxygen is removed. No Drawings

Material and method for promoting the growth of anaerobic bacteria

DOEpatents

Adler, Howard I.

1984-01-01

A material and method for promoting the growth of anaerobic bacteria which includes a nutrient media containing a hydrogen donor and sterile membrane fragments of bacteria having an electron transfer system which reduces oxygen to water. Dissolved oxygen in the medium is removed by adding the sterile membrane fragments to the nutrient medium and holding the medium at a temperature of about 10.degree. to about 60.degree. C. until the dissolved oxygen is removed.

A one-dimensional, steady-state, dissolved-oxygen model and waste-load assimilation study for Little Laughery Creek, Ripley and Franklin counties, Indiana

USGS Publications Warehouse

Crawford, Charles G.; Wilber, William G.; Peters, James G.

1980-01-01

A digital model calibrated to conditions in Little Laughery Creek triutary and Little Laughery Creek, Ripley and Franklin Counties, Ind., was used to predict alternatives for future waste loadings that would be compatible with Indiana stream water-quality standards defined for two critical hydrologic conditions, summer and winter low flows. Natural streamflow during the summer and annual 7-day, 10-year low flow is zero. Headwater flow upstream from the wastewater-treatment facilities consists solely of process cooling water from an industrial discharger. This flow is usually less than 0.5 cubic foot per second. Consequently, benefits from dilution are minimal. As a result, current and projected ammonia-nitrogen concentrations from the municipal discharges will result in in-stream ammonia-nitrogen concentrations that exceed the Indiana ammonia-nitrogen toxicity standards (maximum stream ammonia-nitrogen concentrations of 2.5 and 4.0 milligrams per liter during summer and winter low flows, respectively). Benthic-oxygen demand is probably the most significant factor affecting Little Laughery Creek and is probably responsible for the in-stream dissolved-oxygen concentration being less than the Indiana stream dissolved-oxygen standard (5.0 milligrams per liter) during two water-quality surveys. After municipal dischargers complete advanced waste-treatment facilities, benthic-oxygen demand should be less significant in the stream dissolved-oxygen dynamics. (USGS)

Mineral constituents in water and their significance

USGS Publications Warehouse

Dover, T.B.

1950-01-01

Pure water does not exist in nature. Because water is a powerful solvent, every drop of rain water carries dissolved or suspended material - dust, pollen, and smoke, as well as the atmospheric gases, oxygen, nitrogen and carbon dioxide. When rain falls, the water running over the rocks and percolating through the soil gathers more and more mineral matter in solution. As the uses to which a water supply may be put depend primarily on its mineral content, information concerning the chemical characteristics of water is of importance to each of us. (available as photostat copy only)

Consequences of land use cover change and precipitation regimes on water quality in a tropical landscape: the case of São Paulo, Brazil

NASA Astrophysics Data System (ADS)

Ribeiro Piffer, P.; Reverberi Tambosi, L.; Uriarte, M.

2017-12-01

One of the most pressing challenges faced by modern societies is ensuring a sufficient supply of water considering the ever-growing conflict between environmental conservation and expansion of agricultural and urban frontiers worldwide. Land use cover change have marked effects on natural landscapes, putting key watershed ecosystem services in jeopardy. We investigated the consequences of land use cover change and precipitation regimes on water quality in the state of São Paulo, Brazil, a landscape that underwent major changes in past century. Water quality data collected bi-monthly between 2000 and 2014 from 229 water monitoring stations was analyzed together with 2011 land use cover maps. We focused on six water quality metrics (dissolved oxygen, total nitrogen, total phosphorus, turbidity, total dissolved solids and fecal coliforms) and used generalized linear mixed models to analyze the data. Models were built at two scales, the entire watershed and a 60 meters riparian buffer along the river network. Models accounted for 46-67% of the variance in water quality metrics and, apart from dissolved oxygen, which reflected land cover composition in riparian buffers, all metrics responded to land use at the watershed scale. Highly urbanized areas had low dissolved oxygen and high fecal coliforms, dissolved solids, phosphorus and nitrogen levels in streams. Pasture was associated with increases in turbidity, while sugarcane plantations significantly increased nitrogen concentrations. Watersheds with high forest cover had greater dissolved oxygen and lower turbidity. Silviculture plantations had little impact on water quality. Precipitation decreased dissolved oxygen and was associated with higher levels of turbidity, fecal coliforms and phosphorus. Results indicate that conversion of forest cover to other land uses had negative impacts on water quality in the study area, highlighting the need for landscape restoration to improve watersheds ecosystem services.

The effect of oxygen fugacity on the solubility of carbon-oxygen fluids in basaltic melt

NASA Technical Reports Server (NTRS)

Pawley, Alison R.; Holloway, John R.; Mcmillan, Paul F.

1992-01-01

The solubility of CO2-CO fluids in a midocean ridge basalt have been measured at 1200 C, 500-1500 bar, and oxygen fugacities between NNO and NNO-4. In agreement with results of previous studies, the results reported here imply that, at least at low pressures, CO2 dissolves in basaltic melt only in the form of carbonate groups. The dissolution reaction is heterogeneous, with CO2 molecules in the fluid reacting directly with reactive oxygens in the melt to produce CO3(2-). CO, on the other hand, is insoluble, dissolving neither as carbon, molecular CO, nor CO3(2-). It is shown that, for a given pressure and temperature, the concentration of dissolved carbon-bearing species in basaltic melt in equilibrium with a carbon-oxygen fluid is proportional to the mole fraction of CO2 in the fluid, which is a function of fO2. At low pressures CO2 solubility is a linear function of CO2 fugacity at constant temperatures.

Deoxygenation alters bacterial diversity and community composition in the ocean's largest oxygen minimum zone.

PubMed

Beman, J Michael; Carolan, Molly T

2013-01-01

Oceanic oxygen minimum zones (OMZs) have a central role in biogeochemical cycles and are expanding as a consequence of climate change, yet how deoxygenation will affect the microbial communities that control these cycles is unclear. Here we sample across dissolved oxygen gradients in the oceans' largest OMZ and show that bacterial richness displays a unimodal pattern with decreasing dissolved oxygen, reaching maximum values on the edge of the OMZ and decreasing within it. Rare groups on the OMZ margin are abundant at lower dissolved oxygen concentrations, including sulphur-cycling Chromatiales, for which 16S rRNA was amplified from extracted RNA. Microbial species distribution models accurately replicate community patterns based on multivariate environmental data, demonstrate likely changes in distributions and diversity in the eastern tropical North Pacific Ocean, and highlight the sensitivity of key bacterial groups to deoxygenation. Through these mechanisms, OMZ expansion may alter microbial composition, competition, diversity and function, all of which have implications for biogeochemical cycling in OMZs.

Deoxygenation alters bacterial diversity and community composition in the ocean’s largest oxygen minimum zone

NASA Astrophysics Data System (ADS)

Beman, J. Michael; Carolan, Molly T.

2013-10-01

Oceanic oxygen minimum zones (OMZs) have a central role in biogeochemical cycles and are expanding as a consequence of climate change, yet how deoxygenation will affect the microbial communities that control these cycles is unclear. Here we sample across dissolved oxygen gradients in the oceans’ largest OMZ and show that bacterial richness displays a unimodal pattern with decreasing dissolved oxygen, reaching maximum values on the edge of the OMZ and decreasing within it. Rare groups on the OMZ margin are abundant at lower dissolved oxygen concentrations, including sulphur-cycling Chromatiales, for which 16S rRNA was amplified from extracted RNA. Microbial species distribution models accurately replicate community patterns based on multivariate environmental data, demonstrate likely changes in distributions and diversity in the eastern tropical North Pacific Ocean, and highlight the sensitivity of key bacterial groups to deoxygenation. Through these mechanisms, OMZ expansion may alter microbial composition, competition, diversity and function, all of which have implications for biogeochemical cycling in OMZs.

Welding of 316L Austenitic Stainless Steel with Activated Tungsten Inert Gas Process

NASA Astrophysics Data System (ADS)

Ahmadi, E.; Ebrahimi, A. R.

2015-02-01

The use of activating flux in TIG welding process is one of the most notable techniques which are developed recently. This technique, known as A-TIG welding, increases the penetration depth and improves the productivity of the TIG welding. In the present study, four oxide fluxes (SiO2, TiO2, Cr2O3, and CaO) were used to investigate the effect of activating flux on the depth/width ratio and mechanical property of 316L austenitic stainless steel. The effect of coating density of activating flux on the weld pool shape and oxygen content in the weld after the welding process was studied systematically. Experimental results indicated that the maximum depth/width ratio of stainless steel activated TIG weld was obtained when the coating density was 2.6, 1.3, 2, and 7.8 mg/cm2 for SiO2, TiO2, Cr2O3, and CaO, respectively. The certain range of oxygen content dissolved in the weld, led to a significant increase in the penetration capability of TIG welds. TIG welding with active fluxes can increase the delta-ferrite content and improves the mechanical strength of the welded joint.

Water quality of Lake Whitney, north-central Texas

USGS Publications Warehouse

Strause, Jeffrey L.; Andrews, Freeman L.

1983-01-01

Seasonal temperature variations and variations in the concentration of dissolved oxygen result in dissolved iron, dissolved manganese, total inorganic nitrogen, and total phosphorus being recycled within the lake; however, no significant accumulations of these constituents were detected.

Dissolved Oxygen Sensor in Animal-Borne Instruments: An Innovation for Monitoring the Health of Oceans and Investigating the Functioning of Marine Ecosystems

PubMed Central

Bailleul, Frederic; Vacquie-Garcia, Jade; Guinet, Christophe

2015-01-01

The current decline in dissolved oxygen concentration within the oceans is a sensitive indicator of the effect of climate change on marine environment. However the impact of its declining on marine life and ecosystems’ health is still quite unclear because of the difficulty in obtaining in situ data, especially in remote areas, like the Southern Ocean (SO). Southern elephant seals (Mirounga leonina) proved to be a relevant alternative to the traditional oceanographic platforms to measure physical and biogeochemical structure of oceanic regions rarely observed. In this study, we use a new stage of development in biologging technology to draw a picture of dissolved oxygen concentration in the SO. We present the first results obtained from a dissolved oxygen sensor added to Argos CTD-SRDL tags and deployed on 5 female elephant seals at Kerguelen. From October 2010 and October 2011, 742 oxygen profiles associated with temperature and salinity measurements were recorded. Whether a part of the data must be considered cautiously, especially because of offsets and temporal drifts of the sensors, the range of values recorded was consistent with a concomitant survey conducted from a research vessel (Keops-2 project). Once again, elephant seals reinforced the relationship between marine ecology and oceanography, delivering essential information about the water masses properties and the biological status of the Southern Ocean. But more than the presentation of a new stage of development in animal-borne instrumentation, this pilot study opens a new field of investigation in marine ecology and could be enlarged in a near future to other key marine predators, especially large fish species like swordfish, tuna or sharks, for which dissolved oxygen is expected to play a crucial role in distribution and behaviour. PMID:26200780

Dissolved Oxygen Sensor in Animal-Borne Instruments: An Innovation for Monitoring the Health of Oceans and Investigating the Functioning of Marine Ecosystems.

PubMed

Bailleul, Frederic; Vacquie-Garcia, Jade; Guinet, Christophe

2015-01-01

The current decline in dissolved oxygen concentration within the oceans is a sensitive indicator of the effect of climate change on marine environment. However the impact of its declining on marine life and ecosystems' health is still quite unclear because of the difficulty in obtaining in situ data, especially in remote areas, like the Southern Ocean (SO). Southern elephant seals (Mirounga leonina) proved to be a relevant alternative to the traditional oceanographic platforms to measure physical and biogeochemical structure of oceanic regions rarely observed. In this study, we use a new stage of development in biologging technology to draw a picture of dissolved oxygen concentration in the SO. We present the first results obtained from a dissolved oxygen sensor added to Argos CTD-SRDL tags and deployed on 5 female elephant seals at Kerguelen. From October 2010 and October 2011, 742 oxygen profiles associated with temperature and salinity measurements were recorded. Whether a part of the data must be considered cautiously, especially because of offsets and temporal drifts of the sensors, the range of values recorded was consistent with a concomitant survey conducted from a research vessel (Keops-2 project). Once again, elephant seals reinforced the relationship between marine ecology and oceanography, delivering essential information about the water masses properties and the biological status of the Southern Ocean. But more than the presentation of a new stage of development in animal-borne instrumentation, this pilot study opens a new field of investigation in marine ecology and could be enlarged in a near future to other key marine predators, especially large fish species like swordfish, tuna or sharks, for which dissolved oxygen is expected to play a crucial role in distribution and behaviour.

Effects of dissolved oxygen on dye removal by zero-valent iron.

PubMed

Wang, Kai-Sung; Lin, Chiou-Liang; Wei, Ming-Chi; Liang, Hsiu-Hao; Li, Heng-Ching; Chang, Chih-Hua; Fang, Yung-Tai; Chang, Shih-Hsien

2010-10-15

Effects of dissolved oxygen concentrations on dye removal by zero-valent iron (Fe(0)) were investigated. The Vibrio fischeri light inhibition test was employed to evaluate toxicity of decolorized solution. Three dyes, Acid Orange 7 (AO7, monoazo), Reactive Red 120 (RR120, diazo), and Acid Blue 9 (AB9, triphenylmethane), were selected as model dyes. The dye concentration and Fe(0) dose used were 100 mg L(-1) and 30 g L(-1), respectively. Under anoxic condition, the order for dye decolorization was AO7>RR120>AB9. An increase in the dissolved oxygen concentrations enhanced decolorization and chemical oxygen demand (COD) removal of the three dyes. An increase in gas flow rates also improved dye and COD removals by Fe(0). At dissolved oxygen of 6 mg L(-1), more than 99% of each dye was decolorized within 12 min and high COD removals were obtained (97% for AO7, 87% for RR120, and 93% for AB9). The toxicity of decolorized dye solutions was low (I(5)<40%). An increase in DO concentrations obviously reduced the toxicity. When DO above 2 mg L(-1) was applied, low iron ion concentration (13.6 mg L(-1)) was obtained in the decolorized AO7 solution. 2010 Elsevier B.V. All rights reserved.

Derivation of habitat-specific dissolved oxygen criteria for Chesapeake Bay and its tidal tributaries

USGS Publications Warehouse

Batiuk, Richard A.; Breitburg, Denise L.; Diaz, Robert J.; Cronin, Thomas M.; Secor, David H.; Thursby, Glen

2009-01-01

The Chesapeake 2000 Agreement committed its state and federal signatories to “define the water quality conditions necessary to protect aquatic living resources” in the Chesapeake Bay (USA) and its tidal tributaries. Hypoxia is one of the key water quality issues addressed as a result of the above Agreement. This paper summarizes the protection goals and specific criteria intended to achieve those goals for addressing hypoxia. The criteria take into account the variety of Bay habitats and the tendency towards low dissolved oxygen in some areas of the Bay. Stressful dissolved oxygen conditions were characterized for a diverse array of living resources of the Chesapeake Bay by different aquatic habitats: migratory fish spawning and nursery, shallow-water, open-water, deep-water, and deep-channel. The dissolved oxygen criteria derived for each of these habitats are intended to protect against adverse effects on survival, growth, reproduction and behavior. The criteria accommodate both spatial and temporal aspects of low oxygen events, and have been adopted into the Chesapeake Bay states – Maryland, Virginia, and Delaware – and the District of Columbia's water quality standards regulations. These criteria, now in the form of state regulatory standards, are driving an array of land-based and wastewater pollution reduction actions across the six-watershed.

A linear and non-linear polynomial neural network modeling of dissolved oxygen content in surface water: Inter- and extrapolation performance with inputs' significance analysis.

PubMed

Šiljić Tomić, Aleksandra; Antanasijević, Davor; Ristić, Mirjana; Perić-Grujić, Aleksandra; Pocajt, Viktor

2018-01-01

Accurate prediction of water quality parameters (WQPs) is an important task in the management of water resources. Artificial neural networks (ANNs) are frequently applied for dissolved oxygen (DO) prediction, but often only their interpolation performance is checked. The aims of this research, beside interpolation, were the determination of extrapolation performance of ANN model, which was developed for the prediction of DO content in the Danube River, and the assessment of relationship between the significance of inputs and prediction error in the presence of values which were of out of the range of training. The applied ANN is a polynomial neural network (PNN) which performs embedded selection of most important inputs during learning, and provides a model in the form of linear and non-linear polynomial functions, which can then be used for a detailed analysis of the significance of inputs. Available dataset that contained 1912 monitoring records for 17 water quality parameters was split into a "regular" subset that contains normally distributed and low variability data, and an "extreme" subset that contains monitoring records with outlier values. The results revealed that the non-linear PNN model has good interpolation performance (R 2 =0.82), but it was not robust in extrapolation (R 2 =0.63). The analysis of extrapolation results has shown that the prediction errors are correlated with the significance of inputs. Namely, the out-of-training range values of the inputs with low importance do not affect significantly the PNN model performance, but their influence can be biased by the presence of multi-outlier monitoring records. Subsequently, linear PNN models were successfully applied to study the effect of water quality parameters on DO content. It was observed that DO level is mostly affected by temperature, pH, biological oxygen demand (BOD) and phosphorus concentration, while in extreme conditions the importance of alkalinity and bicarbonates rises over pH and BOD. Copyright © 2017 Elsevier B.V. All rights reserved.

Comparative production of channel catfish and channel x blue hybrid catfish subjected to two minimum dissolved oxygen concentrations

USDA-ARS?s Scientific Manuscript database

The effect of daily minimum dissolved oxygen concentration on growth and yield (kg/ha) of the channel catfish (Ictalurus punctatus) and the channel x blue hybrid catfish (I. punctatus female x I. furcatus male), which shared the Jubilee strain of channel catfish as the maternal parent, was evaluated...

Production of channel catfish and channel x blue hybrid catfish subjected to two minimum dissolved oxygen concentrations

USDA-ARS?s Scientific Manuscript database

As the channel x blue hybrid catfish is stocked by an increasing number of catfish farmers, it is important to quantify the production response of this fish to dissolved oxygen management strategies. The purpose of this study was to compare the production and water quality responses of the channel x...

Hypoxia affects performance traits and body composition of juvenile hybrid striped bass (Morone chrysops x M. saxatilis)

USDA-ARS?s Scientific Manuscript database

Performance traits and body composition of juvenile hybrid striped bass (Morone chrysops x M. saxatilis) in response to hypoxia were evaluated in replicate tanks maintained at constant dissolved oxygen concentrations that averaged 23.0 +/- 2.3%, 39.7 +/- 3.0%, and 105.5 +/- 9.5% dissolved oxygen sat...

Historic and recent patterns in dissolved oxygen within the Yaquina Estuary (Oregon, USA): Importance of anthropogenic activities and oceanic conditions

EPA Science Inventory

Spatial and temporal patterns of dissolved oxygen (DO) in Yaquina Estuary, Oregon (USA) are examined using historic and recent data. There was a significant increasing trend in DO in the upstream portion of the estuary during the years 1960–1985. Historically, minimum dry season ...

Improving estimates of ecosystem metabolism by reducing effects of tidal advection on dissolved oxygen time series-Abstract

EPA Science Inventory

Continuous time series of dissolved oxygen (DO) have been used to compute estimates of metabolism in aquatic ecosystems. Central to this open water or "Odum" method is the assumption that the DO time is not strongly affected by advection and that effects due to advection or mixin...

Predator density and dissolved oxygen affect body condition of Stenonema tripunctatum (Ephemeroptera, Heptageniidae) from intermittent streams

Treesearch

Joseph W. Love; Christopher M. Taylor; Melvin L. Warren

2005-01-01

The effects of population density, fish density, and dissolved oxygen on body condition of late-instar nymphs of Stenonema tripunctatum (Ephemeroptera, Heptageniidae) were investigated using nymphs sampled from isolated, upland stream pools over summer in central Arkansas, USA. All three factors exhibited high variation among pools. Body condition...

Oxygen Response of the Wine Yeast Saccharomyces cerevisiae EC1118 Grown under Carbon-Sufficient, Nitrogen-Limited Enological Conditions

PubMed Central

Aceituno, Felipe F.; Orellana, Marcelo; Torres, Jorge; Mendoza, Sebastián; Slater, Alex W.; Melo, Francisco

2012-01-01

Discrete additions of oxygen play a critical role in alcoholic fermentation. However, few studies have quantitated the fate of dissolved oxygen and its impact on wine yeast cell physiology under enological conditions. We simulated the range of dissolved oxygen concentrations that occur after a pump-over during the winemaking process by sparging nitrogen-limited continuous cultures with oxygen-nitrogen gaseous mixtures. When the dissolved oxygen concentration increased from 1.2 to 2.7 μM, yeast cells changed from a fully fermentative to a mixed respirofermentative metabolism. This transition is characterized by a switch in the operation of the tricarboxylic acid cycle (TCA) and an activation of NADH shuttling from the cytosol to mitochondria. Nevertheless, fermentative ethanol production remained the major cytosolic NADH sink under all oxygen conditions, suggesting that the limitation of mitochondrial NADH reoxidation is the major cause of the Crabtree effect. This is reinforced by the induction of several key respiratory genes by oxygen, despite the high sugar concentration, indicating that oxygen overrides glucose repression. Genes associated with other processes, such as proline uptake, cell wall remodeling, and oxidative stress, were also significantly affected by oxygen. The results of this study indicate that respiration is responsible for a substantial part of the oxygen response in yeast cells during alcoholic fermentation. This information will facilitate the development of temporal oxygen addition strategies to optimize yeast performance in industrial fermentations. PMID:23001663

Oxygen response of the wine yeast Saccharomyces cerevisiae EC1118 grown under carbon-sufficient, nitrogen-limited enological conditions.

PubMed

Aceituno, Felipe F; Orellana, Marcelo; Torres, Jorge; Mendoza, Sebastián; Slater, Alex W; Melo, Francisco; Agosin, Eduardo

2012-12-01

Discrete additions of oxygen play a critical role in alcoholic fermentation. However, few studies have quantitated the fate of dissolved oxygen and its impact on wine yeast cell physiology under enological conditions. We simulated the range of dissolved oxygen concentrations that occur after a pump-over during the winemaking process by sparging nitrogen-limited continuous cultures with oxygen-nitrogen gaseous mixtures. When the dissolved oxygen concentration increased from 1.2 to 2.7 μM, yeast cells changed from a fully fermentative to a mixed respirofermentative metabolism. This transition is characterized by a switch in the operation of the tricarboxylic acid cycle (TCA) and an activation of NADH shuttling from the cytosol to mitochondria. Nevertheless, fermentative ethanol production remained the major cytosolic NADH sink under all oxygen conditions, suggesting that the limitation of mitochondrial NADH reoxidation is the major cause of the Crabtree effect. This is reinforced by the induction of several key respiratory genes by oxygen, despite the high sugar concentration, indicating that oxygen overrides glucose repression. Genes associated with other processes, such as proline uptake, cell wall remodeling, and oxidative stress, were also significantly affected by oxygen. The results of this study indicate that respiration is responsible for a substantial part of the oxygen response in yeast cells during alcoholic fermentation. This information will facilitate the development of temporal oxygen addition strategies to optimize yeast performance in industrial fermentations.

Electrochemical and Chemical Complications Resulting from Yeast Extract Addition to Stimulate Microbial Growth

DTIC Science & Technology

2016-09-22

approxi- mately 21% dissolved oxygen ) and deoxygenated (ɘ.0001% dissolved oxygen ) natural seawater fixed the corrosion potential (Ecorr) of 316L (UNS...at 70°C for 2 h, and allowed to cool to room temperature (23±1°C) overnight. Electrochemical measurements were conducted in Model K0047† corrosion...Coy Laboratory Products). Palladium (Pd) catalyst stacks were placed within the chamber to maintain the atmospheric oxygen level to below 1 part-per

Work Plan for Three-Dimensional Time-Varying, Hydrodynamic and Water Quality Model of Chesapeake Bay

DTIC Science & Technology

1988-08-01

successfully calibrated: a. Dissolved oxygen b. Anmonium c. Nitrate d . Dissolved inorganic phosphorus e. Silica f. Methane g. Sulfide Fluxes of dissolved...oxygen, amonium , nitrate , methane, and sulfide can be related to the rate of diagenesis. A less mechanistic, more empirical approach may be required...CLASSc;CA’ ON A ’I.ORITV 3 D.S1R RUT ON AVA LABMLTY OF REPORT ’b D LASPCTO1,DONGRANG C ED, kApproved for public rele~ise; distribution 2b DC~ASFAT.N

Dually Fluorescent Sensing of pH and Dissolved Oxygen Using a Membrane Made from Polymerizable Sensing Monomers.

PubMed

Tian, Yanqing; Shumway, Bradley R; Youngbull, A Cody; Li, Yongzhong; Jen, Alex K-Y; Johnson, Roger H; Meldrum, Deirdre R

2010-06-03

Using a thermal polymerization approach and polymerizable pH and oxygen sensing monomers with green and red emission spectra, respectively, new pH, oxygen, and their dual sensing membranes were prepared using poly(2-hydroxyethyl methacrylate)-co-poly(acrylamide) as a matrix. The sensors were grafted on acrylate-modified quartz glass and characterized under different pH values, oxygen concentrations, ion strengths, temperatures and cell culture media. The pH and oxygen sensors were excited using the same excitation wavelength and exhibited well-separated emission spectra. The pH-sensing films showed good response over the pH range 5.5 to 8.5, corresponding to pK(a) values in the biologically-relevant range between 6.9 and 7.1. The oxygen-sensing films exhibited linear Stern-Volmer quenching responses to dissolved oxygen. As the sensing membranes were prepared using thermally initiated polymerization of sensing moiety-containing monomers, no leaching of the sensors from the membranes to buffers or medium was observed. This advantageous characteristic accounts in part for the sensors' biocompatibility without apparent toxicity to HeLa cells after 40 hours incubation. The dual-sensing membrane was used to measure pH and dissolved oxygen simultaneously. The measured results correlated with the set-point values.

The vertical structure of upper ocean variability at the Porcupine Abyssal Plain during 2012–2013

PubMed Central

Heywood, Karen J.; Thompson, Andrew F.; Binetti, Umberto; Kaiser, Jan

2016-01-01

Abstract This study presents the characterization of variability in temperature, salinity and oxygen concentration, including the vertical structure of the variability, in the upper 1000 m of the ocean over a full year in the northeast Atlantic. Continuously profiling ocean gliders with vertical resolution between 0.5 and 1 m provide more information on temporal variability throughout the water column than time series from moorings with sensors at a limited number of fixed depths. The heat, salt and dissolved oxygen content are quantified at each depth. While the near surface heat content is consistent with the net surface heat flux, heat content of the deeper layers is driven by gyre‐scale water mass changes. Below ∼150m, heat and salt content display intraseasonal variability which has not been resolved by previous studies. A mode‐1 baroclinic internal tide is detected as a peak in the power spectra of water mass properties. The depth of minimum variability is at ∼415m for both temperature and salinity, but this is a depth of high variability for oxygen concentration. The deep variability is dominated by the intermittent appearance of Mediterranean Water, which shows evidence of filamentation. Susceptibility to salt fingering occurs throughout much of the water column for much of the year. Between about 700–900 m, the water column is susceptible to diffusive layering, particularly when Mediterranean Water is present. This unique ability to resolve both high vertical and temporal variability highlights the importance of intraseasonal variability in upper ocean heat and salt content, variations that may be aliased by traditional observing techniques. PMID:27840785

Exoenzyme activities as indicators of dissolved organic matter composition in the hyporheic zone of a floodplain river

Treesearch

Sandra M. Clinton; Rick T. Edwards; Stuart E.G. Findlay

2010-01-01

We measured the hyporheic microbial exoenzyme activities in a floodplain river to determine whether dissolved organic matter (DOM) bioavailability varied with overlying riparian vegetation patch structure or position along flowpaths. Particulate organic matter (POM), dissolved organic carbon (DOC), dissolved oxygen (DO), electrical conductivity and temperature were...

Sulfide Melts and Chalcophile Element Behavior in High Temperature Systems

NASA Astrophysics Data System (ADS)

Wood, B. J.; Kiseeva, K.

2016-12-01

We recently found that partition coefficients (Di) of many weakly and moderately chalcophile elements (e.g., Cd, Zn, Co, Cr, Pb, Sb, In) between sulfide and silicate melts are simple functions of the FeO content of the silicate liquid: logDi A-Blog[FeO] where [FeO] is the FeO concentration in the silicate, A and B are constants and the latter is related to the valency of the element of interest. In contrast, some strongly chalcophile (e.g Cu, Ni, Ag) and lithophile elements (e.g Mn) show marked deviations from linearity on a plot of logDi vs log[FeO]. More recent experiments show that linear behavior is confined to elements whose affinities for S and O are similar to those of Fe. In the case of elements more strongly lithophile than Fe (Ti, U, REE, Zr, Nb, Ta, Mn) a plot of logDi versus log[FeO] describes a U-shape with the element partitioning strongly into the sulfide at very low FeO and again at very high FeO content of the silicate melt. In contrast, strongly chalcophile elements (Cu, Ni, Ag) describe an n-shape on the plot of logD vs log[FeO]. The result is that lithophile elements such as Nb become more "chalcophile" than Cu at very low and very high FeO contents of the silicate melt. The reasons for this surprising behavior are firstly that, at very low FeO contents the silicate melt dissolves substantial amounts of sulfur, which drives down the activity of FeO and, from mass-action "pulls" the lihophile element into the sulfide. At high FeO contents of the silicate the sulfide itself starts to dissolve substantial amounts of oxygen and lithophile elements follow the oxygen into the sulfide. Given the principles which we have established, we are able to describe the patterns of chalcophile element behavior during partial melting and fractional crystallisation on Earth and also on bodies such as Mercury and Mars which are, respectively, strongly reduced relative to Earth and more oxidised than Earth.

Morphological deformities in Chironomus spp. (Diptera: Chironomidae) larvae as a tool for impact assessment of anthropogenic and environmental stresses on three rivers in the Juru river system, Penang, Malaysia.

PubMed

Al-Shami, Salman; Rawi, Che Salmah M; Nor, Siti Azizah M; Ahmad, Abu Hassan; Ali, Arshad

2010-02-01

Morphological deformities in parts of the head capsule of Chironomus spp. larvae inhabiting three polluted rivers (Permatang Rawa [PRR], Pasir [PR], and Kilang Ubi [KUR]) in the Juru River Basin, northeastern peninsular Malaysia, were studied. Samples of the fourth-instar larvae at one location in each river were collected monthly from November 2007 to March 2008 and examined for deformities of the mentum, antenna, mandible, and epipharyngis. At each sample location, in situ measurements of water depth, river width, water pH, dissolved oxygen, and water temperature were made. Samples of river water and benthic sediments were also collected monthly from each larval sample location in each river and taken to the laboratory for appropriate analysis. Total suspended solids (TSSs), ammonium-N, nitrate-N, phosphate-P, chloride, sulfate, and aluminum content in water were analyzed. Total organic matter and nonresidual metals in the sediment samples were also analyzed. Among the three rivers, the highest mean deformity (47.17%) was recorded in larvae collected from KUR that received industrial discharges from surrounding garment and rubber factories, followed by PRR (33.71%) receiving primarily residues of fertilizers and pesticides from adjacent rice fields, and PR (30.34%) contaminated primarily by anthropogenic wastes from the surrounding residential areas. Among the various head capsule structures, deformity of the mentum was strongly reflective of environmental stress and amounted to 27.9, 20.87, and 30.19% in the PRR, PR, and KUR, respectively. Calculated Lenat's toxic score index satisfactorily explained the influence of prevailing environmental variables on the severity of mentum deformities. Redundancy analysis and forward selection selected TSSs, sediment Zn, Mn, Cu, and Ni, and water pH, dissolved oxygen, water temperature, total organic matter, nitrate-N, chloride, phosphate-P, ammonium-N, sulfate, and aluminum as parameters that significantly affected some proportion of deformities. The total deformities correlated closely with deformities of mentum but only weakly with deformities in other parts of head. The total deformity incidence was strongly correlated with high contents of sediment Mn and Ni. The mentum and epipharyngis deformities incidence was highly correlated with an increase of TSSs, total aluminum, and ammonium-N and a decrease in pH and dissolved oxygen.

A study on the applicability of the ecosystem model on water quality prediction in urban river outer moats of Yedo Castle, Nihonbashi River

NASA Astrophysics Data System (ADS)

Kakinuma, Daiki; Tsushima, Yuki; Ohdaira, Kazunori; Yamada, Tadashi

2015-04-01

The objective of the study is to elucidate the waterside environment in the outer moats of Yedo Castle and the downstream of Nihonbashi River in Tokyo. Scince integrated sewage system has been installed in the area around the outer moats of Yedo Castle and the Nihon River basin, when rainfall exceeds more than the sewage treatment capacity, overflowed untreated wastewater is released into the moats and the river. Because the moats is a closed water body, pollutants are deposited to the bottom without outflowing. While reeking offensive odors due to the decomposition, blue-green algae outbreaks affected by the residence time and eluted nutrient causes problems. Scince the Nihonbashi River is a typical tidal river in urban area, the water pollution problems in the river is complicated. This study clarified the characteristics of the water quality in terms of dissolved oxygen saturation through on-site observations. In particular, dissolved oxygen saturation in summer, it is clarified that variations from a supersaturated state due to the variations of horizontal insolation intensity and water temperature up to hypoxic water conditions in the moats. According to previous studies on the water quality of Nihonbashi River, it is clarified that there are three types of variations of dissolved oxygen which desided by rainfall scale. The mean value of dissolved oxygen saturation of all layers has decreased by about 20% at the spring tide after dredging, then it recoveres gradually and become the value before dredging during about a year. Further more, in places where sewage inflows, it is important to developed a ecosystem medel and the applicability of the model. 9 variables including cell quota (intracellular nutrients of phytoplankton) of phosphorus and nitrogen with considerring the nitrification of ammonia nitrogen are used in the model. This model can grasp the sections (such as oxygen production by photosynthesis of phytoplankton, oxygen consumption by respiration of plankton, and bottom mud) of dissolved oxygen concentration.

Low temperature alkaline pH hydrolysis of oxygen-free Titan tholins

NASA Astrophysics Data System (ADS)

Brassé, C.; Buch, A.; Raulin, F.; Coll, P.; Poch, O.; Ramirez, S.

2013-09-01

Titan, the largest moon of Saturn, is known for its dense and nitrogen-rich atmosphere. The organic aerosols which are produced in Titan's atmosphere are objects of astrobiological interest. In this paper we focus on their potential chemical evolution when they reach the surface and interact with putative ammonia-water cryomagma[1]. In this context we have studied the evolution of alkaline pH hydrolysis of Titan tholins (produced by an experimental setup using a plasma DC discharge named PLASMA) at ambient and low temperature. However, we identified oxygenated molecules in non-hydrolyzed tholins meaning that oxygen gets in the PLASMA reactor during the tholins synthesis [2]. Following this preliminary study the synthesis protocol has been improved by isolating the whole device in a specially designed glove box which protect the PLASMA experiment from the laboratory atmosphere. After confirming the non-presence of oxygen in tholins produced with this new experimental setup, the study of oxygen-free tholins' evolution has been carried out. A recent study shows that the subsurface ocean may contain a lower fraction of ammonia (about 5wt% or less [3]), as previously described by other teams [2,4]. Thus new hydrolysis experiments will take this lower value into account. Additionally, a new report [5] provides upper and lower limits for the bulk content of Titan's interior for various gas species. It also shows that most of them are likely stored and dissolved in the subsurface water ocean. But considering the plausible acido-alkaline properties of the ammonia-water ocean, additional species could be dissolved in the ocean and present in the magma. They were also included in our hydrolysis experiments. Taking into account these new data, four different hydrolysis have been applied to oxygen-free tholins. For each type of hydrolysis, we also follow the influence of the hydrolysis temperature on the organic molecules production. The preliminary qualitative and quantitative results of those experiments will be presented at EPSC.

The effect of dissolved oxygen on the susceptibility of blood.

PubMed

Berman, Avery J L; Ma, Yuhan; Hoge, Richard D; Pike, G Bruce

2016-01-01

It has been predicted that, during hyperoxia, excess O2 dissolved in arterial blood will significantly alter the blood's magnetic susceptibility. This would confound the interpretation of the hyperoxia-induced blood oxygenation level-dependent signal as arising solely from changes in deoxyhemoglobin. This study, therefore, aimed to determine how dissolved O2 affects the susceptibility of blood. We present a comprehensive model for the effect of dissolved O2 on the susceptibility of blood and compare it with another recently published model, referred to here as the ideal gas model (IGM). For validation, distilled water and samples of bovine plasma were oxygenated over a range of hyperoxic O2 concentrations and their susceptibilities were determined using multiecho gradient echo phase imaging. In distilled water and plasma, the measured changes in susceptibility were very linear, with identical slopes of 0.062 ppb/mm Hg of O2. This change was dramatically less than previously predicted using the IGM and was close to that predicted by our model. The primary source of error in the IGM is the overestimation of the volume fraction occupied by dissolved O2. Under most physiological conditions, the susceptibility of dissolved O2 can be disregarded in MRI studies employing hyperoxia. © 2015 Wiley Periodicals, Inc.

Chemical oxidation of carwash industry wastewater as an effort to decrease water pollution

NASA Astrophysics Data System (ADS)

Bhatti, Zulfiqar Ahmad; Mahmood, Qaisar; Raja, Iftikhar Ahmad; Malik, Amir Haider; Khan, Muhammad Suleman; Wu, Donglei

Car wash wastewater (CWW) contains petroleum, hydrofluoric acid, ammonium bifluoride products, paint residues, rubber, phosphates, oil, grease and volatile organic compounds (VOCs). The present study dealt with various investigations conducted for the treatment of CWW. A treatment system of 5 L capacity was designed in the laboratory. Due to high load of oil and grease, CWW was aerated and scum was removed. Alum was used as coagulant in primary treatment which resulted 93% and 97% reduction in COD and turbidity. During secondary treatment CWW was further treated with waste hydrogen peroxide which resulted in further 71% and 83% reduction in COD and turbidity, respectively. Other desirable changes were also observed in pH, total dissolved solids (TDS), conductivity and dissolved oxygen contents. It was concluded that designed system could be effectively used to treat carwash wastewater that could be reused in the same station.

Dissolved oxygen, stream temperature, and fish habitat response to environmental water purchases.

PubMed

Null, Sarah E; Mouzon, Nathaniel R; Elmore, Logan R

2017-07-15

Environmental water purchases are increasingly used for ecological protection. In Nevada's Walker Basin (western USA), environmental water purchases augment streamflow in the Walker River and increase lake elevation of terminal Walker Lake. However, water quality impairments like elevated stream temperatures and low dissolved oxygen concentrations also limit ecosystems and species, including federally-threatened Lahontan cutthroat trout. In this paper, we prioritize water volumes and locations that most enhance water quality for riverine habitat from potential environmental water rights purchases. We monitored and modeled streamflows, stream temperatures, and dissolved oxygen concentrations using River Modeling System, an hourly, physically-based hydrodynamic and water quality model. Modeled environmental water purchases ranged from average daily increases of 0.11-1.41 cubic meters per second (m 3 /s) during 2014 and 2015, two critically dry years. Results suggest that water purchases consistently cooled maximum daily stream temperatures and warmed nightly minimum temperatures. This prevented extremely low dissolved oxygen concentrations below 5.0 mg/L, but increased the duration of moderate conditions between 5.5 and 6.0 mg/L. Small water purchases less than approximately 0.71 m 3 /s per day had little benefit for Walker River habitat. Dissolved oxygen concentrations were affected by upstream environmental conditions, where suitable upstream water quality improved downstream conditions and vice versa. Overall, this study showed that critically dry water years degrade environmental water quality and habitat, but environmental water purchases of at least 0.71 m 3 /s were promising for river restoration. Published by Elsevier Ltd.

Episodes of low dissolved oxygen indicated by ostracodes and sediment geochemistry at Crystal Lake, Illinois, USA

USGS Publications Warehouse

Curry, B. Brandon; Filippelli, G.M.

2010-01-01

Low dissolved oxygen during the summer and early fall controls profundal continental ostracode distribution in Crystal Lake (McHenry County), Illinois, favoring Cypria ophthalmica and Physocypria globula at water depths from 6 to 13 m. These species also thrived in the lake's profundal zone from 14,165 to 9600 calendar year before present (cal yr b.p.) during the late Boiling, Allerod, and Younger Dryas chronozones, and early Holocene. Characterized by sand, cemented tubules, large aquatic gastropod shells, and littoral ostracode valves, thin (1-6 cm) tempestite deposits punctuate thicker deposits of organic gyttja from 16,080 to 11,900 cal yr b.p. The succeeding 2300 yr (11,900-9600 cal yr b.p.) lack tempestites, and reconstructed water depths were at their maximum. Deposition of marl under relatively well-oxygenated conditions occurred during the remainder of the Holocene until the arrival of Europeans, when the lake returned to a pattern of seasonally low dissolved oxygen. Such conditions are also indicated in the lake sediment by the speciation of phosphorus, high concentrations of organic carbon, and abundant iron and manganese occluded to mineral grains. Initial low dissolved oxygen was probably caused by the delivery of dissolved P and Fe in shallow groundwater, the chemistry of which was influenced by Spodosol pedogenesis under a spruce forest. The triggering may have been regionally warm and wet conditions associated with retreat of the Lake Michigan lobe (south-central Laurentide Ice Sheet). ?? 2010, by the American Society of Limnology and Oceanography Inc.

Accounting for the Decreasing Reaction Potential of Heterogeneous Aquifers in a Stochastic Framework of Aquifer-Scale Reactive Transport

NASA Astrophysics Data System (ADS)

Loschko, Matthias; Wöhling, Thomas; Rudolph, David L.; Cirpka, Olaf A.

2018-01-01

Many groundwater contaminants react with components of the aquifer matrix, causing a depletion of the aquifer's reactivity with time. We discuss conceptual simplifications of reactive transport that allow the implementation of a decreasing reaction potential in reactive-transport simulations in chemically and hydraulically heterogeneous aquifers without relying on a fully explicit description. We replace spatial coordinates by travel-times and use the concept of relative reactivity, which represents the reaction-partner supply from the matrix relative to a reference. Microorganisms facilitating the reactions are not explicitly modeled. Solute mixing is neglected. Streamlines, obtained by particle tracking, are discretized in travel-time increments with variable content of reaction partners in the matrix. As exemplary reactive system, we consider aerobic respiration and denitrification with simplified reaction equations: Dissolved oxygen undergoes conditional zero-order decay, nitrate follows first-order decay, which is inhibited in the presence of dissolved oxygen. Both reactions deplete the bioavailable organic carbon of the matrix, which in turn determines the relative reactivity. These simplifications reduce the computational effort, facilitating stochastic simulations of reactive transport on the aquifer scale. In a one-dimensional test case with a more detailed description of the reactions, we derive a potential relationship between the bioavailable organic-carbon content and the relative reactivity. In a three-dimensional steady-state test case, we use the simplified model to calculate the decreasing denitrification potential of an artificial aquifer over 200 years in an ensemble of 200 members. We demonstrate that the uncertainty in predicting the nitrate breakthrough in a heterogeneous aquifer decreases with increasing scale of observation.

A record of deep-ocean dissolved O2 from the oxidation state of iron in submarine basalts.

PubMed

Stolper, Daniel A; Keller, C Brenhin

2018-01-18

The oxygenation of the deep ocean in the geological past has been associated with a rise in the partial pressure of atmospheric molecular oxygen (O 2 ) to near-present levels and the emergence of modern marine biogeochemical cycles. It has also been linked to the origination and diversification of early animals. It is generally thought that the deep ocean was largely anoxic from about 2,500 to 800 million years ago, with estimates of the occurrence of deep-ocean oxygenation and the linked increase in the partial pressure of atmospheric oxygen to levels sufficient for this oxygenation ranging from about 800 to 400 million years ago. Deep-ocean dissolved oxygen concentrations over this interval are typically estimated using geochemical signatures preserved in ancient continental shelf or slope sediments, which only indirectly reflect the geochemical state of the deep ocean. Here we present a record that more directly reflects deep-ocean oxygen concentrations, based on the ratio of Fe 3+ to total Fe in hydrothermally altered basalts formed in ocean basins. Our data allow for quantitative estimates of deep-ocean dissolved oxygen concentrations from 3.5 billion years ago to 14 million years ago and suggest that deep-ocean oxygenation occurred in the Phanerozoic (541 million years ago to the present) and potentially not until the late Palaeozoic (less than 420 million years ago).

A record of deep-ocean dissolved O2 from the oxidation state of iron in submarine basalts

NASA Astrophysics Data System (ADS)

Stolper, Daniel A.; Keller, C. Brenhin

2018-01-01

The oxygenation of the deep ocean in the geological past has been associated with a rise in the partial pressure of atmospheric molecular oxygen (O2) to near-present levels and the emergence of modern marine biogeochemical cycles. It has also been linked to the origination and diversification of early animals. It is generally thought that the deep ocean was largely anoxic from about 2,500 to 800 million years ago, with estimates of the occurrence of deep-ocean oxygenation and the linked increase in the partial pressure of atmospheric oxygen to levels sufficient for this oxygenation ranging from about 800 to 400 million years ago. Deep-ocean dissolved oxygen concentrations over this interval are typically estimated using geochemical signatures preserved in ancient continental shelf or slope sediments, which only indirectly reflect the geochemical state of the deep ocean. Here we present a record that more directly reflects deep-ocean oxygen concentrations, based on the ratio of Fe3+ to total Fe in hydrothermally altered basalts formed in ocean basins. Our data allow for quantitative estimates of deep-ocean dissolved oxygen concentrations from 3.5 billion years ago to 14 million years ago and suggest that deep-ocean oxygenation occurred in the Phanerozoic (541 million years ago to the present) and potentially not until the late Palaeozoic (less than 420 million years ago).

Limiting factors to encapsulation: the combined effects of dissolved protein and oxygen availability on embryonic growth and survival of species with contrasting feeding strategies.

PubMed

Brante, Antonio; Fernández, Miriam; Viard, Frédérique

2009-07-01

Encapsulation is a common strategy among marine invertebrate species. It has been shown that oxygen and food availability independently constrain embryo development during intracapsular development. However, it is unclear how embryos of species with different feeding strategies perceive these two constraints when operating jointly. In the present study, we examined the relative importance of dissolved albumen, as a food source, oxygen condition and their interaction on embryonic growth and the survival of two calyptraeid species, Crepidula coquimbensis and Crepidula fornicata, exhibiting different embryo feeding behaviours (i.e. presence vs absence of intracapsular cannibalism). Two oxygen condition treatments (normoxia and hypoxia) and three albumen concentrations (0, 1 and 2 mg l(-1)) were studied. In addition, albumen intake by embryos was observed using fluorescence microscopy. Our study shows that embryos of both species incorporated dissolved albumen but used a different set of embryonic organs. We observed that embryo growth rates in C. coquimbensis were negatively affected only by hypoxic conditions. Conversely, a combination of low albumen concentration and oxygen availability slowed embryo growth in C. fornicata. These findings suggest that oxygen availability is a limiting factor for the normal embryo development of encapsulated gastropod species, regardless of feeding behaviour or developmental mode. By contrast, the effect of dissolved albumen as an alternative food source on embryo performance may depend on the feeding strategy of the embryos.

Significance of dissolved methane in effluents of anaerobically ...

EPA Pesticide Factsheets

The need for energy efficient Domestic Wastewater (DWW) treatment is increasing annually with population growth and expanding global energy demand. Anaerobic treatment of low strength DWW produces methane which can be used to as an energy product. Temperature sensitivity, low removal efficiencies (Chemical Oxygen Demand (COD), Suspended Solids (SS), and Nutrients), alkalinity demand, and potential greenhouse gas (GHG) emissions have limited its application to warmer climates. Although well designed anaerobic Membrane Bioreactors (AnMBRs) are able to effectively treat DWW at psychrophilic temperatures (10–30 °C), lower temperatures increase methane solubility leading to increased energy losses in the form of dissolved methane in the effluent. Estimates of dissolved methane losses are typically based on concentrations calculated using Henry's Law but advection limitations can lead to supersaturation of methane between 1.34 and 6.9 times equilibrium concentrations and 11–100% of generated methane being lost in the effluent. In well mixed systems such as AnMBRs which use biogas sparging to control membrane fouling, actual concentrations approach equilibrium values. Non-porous membranes have been used to recover up to 92.6% of dissolved methane and well suited for degassing effluents of Upflow Anaerobic Sludge Blanket (UASB) reactors which have considerable solids and organic contents and can cause pore wetting and clogging in microporous membrane modules. Micro

Rainbow trout responses to water temperature and dissolved oxygen stress in two southern California stream pools

Treesearch

K.R. Matthews; N.H. Berg

1997-01-01

Habitat use by rainbow trout Oncorhynchus mykiss is described for a southern California stream where the summer water temperatures typically exceed the lethal limits for trout (>25) C). During August 1994, water temperature, dissolved oxygen (DO), and trout distribution were monitored in two adjacent pools in Sespe Creek, Ventura County, where summer water...

The Effect of Increased Temperatures and Ultraviolet Radiation on Dissolved Oxygen in Ecosystems Primarily Comprised of "Euglena"

ERIC Educational Resources Information Center

Carpenter, Matt

2009-01-01

The purpose of this study was to determine whether increased levels of UV radiation and temperatures from global warming have a significant impact on dissolved oxygen (DO) output from the alga, "Euglena," which affects other organisms in the ecosystem. The original hypothesis stated that if temperature was increased along with exposure time to…

Effects of the rate of releases from Sam Rayburn Reservoir on the Aeration Capacity of the Angelina River, eastern Texas

USGS Publications Warehouse

Rawson, Jack; Goss, Richard L.; Rathbun, Ira G.

1980-01-01

A three-phase study was conducted during July and August 1979 to determine the effects of varying release rates through the power-outlet works at Sam Rayburn Reservoir, eastern Texas, on aeration capacity of a 14-mile reach of the Angelina River below Sam Rayburn Dam. The dominant factors that affected the aeration capacity during the study time were time of travel and the dissolved-oxygen deficit of the releases. Aeration was low throughout the study but increased in response to increases in the dissolved-oxygen deficit and the duration of time that the releases were exposed to the atmosphere (time of travel). The average concentration of dissolved oxygen sustained by release of 8,800 cubic feet per second decreased from 5.0 milligrams per liter at a site near the power outlet to 4.8 milligrams per liter at a site about 14 miles downstream; the time of travel averaged about 8 hours. The average concentration of dissolved oxygen in flow sustained by releases of 2,200 cubic feet per second increased from 5.2 to 5.5 milligrams per liter; the time of travel averaged about 20 hours. (USGS)

Water-quality reconnaissance of Laguna Tortuguero, Vega Baja, Puerto Rico, March 1999-May 2000

USGS Publications Warehouse

Soler-Lopez, Luis; Guzman-Rios, Senen; Conde-Costas, Carlos

2006-01-01

The Laguna Tortuguero, a slightly saline to freshwater lagoon in north-central Puerto Rico, has a surface area of about 220 hectares and a mean depth of about 1.2 meters. As part of a water-quality reconnaissance, water samples were collected at about monthly and near bi-monthly intervals from March 1999 to May 2000 at four sites: three stations inside the lagoon and one station at the artificial outlet channel dredged in 1940, which connects the lagoon with the Atlantic Ocean. Physical characteristics that were determined from these water samples were pH, temperature, specific conductance, dissolved oxygen, dissolved oxygen saturation, and discharge at the outlet canal. Other water-quality constituents also were determined, including nitrogen and phosphorus species, organic carbon, chlorophyll a and b, plankton biomass, hardness, alkalinity as calcium carbonate, and major ions. Additionally, a diel study was conducted at three stations in the lagoon to obtain data on the diurnal variation of temperature, specific conductance, dissolved oxygen, and dissolved oxygen saturation. The data analysis indicates the water quality of Laguna Tortuguero complies with the Puerto Rico Environmental Quality Board standards and regulations.

Bacterial survival and association with sludge flocs during aerobic and anaerobic digestion of wastewater sludge under laboratory conditions.

PubMed Central

Farrah, S R; Bitton, G

1983-01-01

The fate of indicator bacteria, a bacterial pathogen, and total aerobic bacteria during aerobic and anaerobic digestion of wastewater sludge under laboratory conditions was determined. Correlation coefficients were calculated between physical and chemical parameters (temperature, dissolved oxygen, pH, total solids, and volatile solids) and either the daily change in bacterial numbers or the percentage of bacteria in the supernatant. The major factor influencing survival of Salmonella typhimurium and indicator bacteria during aerobic digestion was the temperature of sludge digestion. At 28 degrees C with greater than 4 mg of dissolved oxygen per liter, the daily change in numbers of these bacteria was approximately -1.0 log10/ml. At 6 degrees C, the daily change was less than -0.3 log10/ml. Most of the bacteria were associated with the sludge flocs during aerobic digestion of sludge at 28 degrees C with greater than 2.4 mg of dissolved oxygen per liter. Lowering the temperature or the amount of dissolved oxygen decreased the fraction of bacteria associated with the flocs and increased the fraction found in the supernatant. PMID:6401978

Enhancing dissolved oxygen control using an on-line hybrid fuzzy-neural soft-sensing model-based control system in an anaerobic/anoxic/oxic process.

PubMed

Huang, Mingzhi; Wan, Jinquan; Hu, Kang; Ma, Yongwen; Wang, Yan

2013-12-01

An on-line hybrid fuzzy-neural soft-sensing model-based control system was developed to optimize dissolved oxygen concentration in a bench-scale anaerobic/anoxic/oxic (A(2)/O) process. In order to improve the performance of the control system, a self-adapted fuzzy c-means clustering algorithm and adaptive network-based fuzzy inference system (ANFIS) models were employed. The proposed control system permits the on-line implementation of every operating strategy of the experimental system. A set of experiments involving variable hydraulic retention time (HRT), influent pH (pH), dissolved oxygen in the aerobic reactor (DO), and mixed-liquid return ratio (r) was carried out. Using the proposed system, the amount of COD in the effluent stabilized at the set-point and below. The improvement was achieved with optimum dissolved oxygen concentration because the performance of the treatment process was optimized using operating rules implemented in real time. The system allows various expert operational approaches to be deployed with the goal of minimizing organic substances in the outlet while using the minimum amount of energy.

Deadzones, Dying Eddies, and the Loop Current: Stability, Ventilation, and Heat Content from Buoyancy Glider Observations in the Northwest Gulf of Mexico in Spring and Summer 2015

NASA Astrophysics Data System (ADS)

DiMarco, S. F.; Knap, A. H.; Wang, Z.; Walpert, J.; Dreger, K.

2016-02-01

The northwestern Gulf of Mexico is host to a myriad of physical and biochemical processes, which govern the exchange and transport of material and volume between the coastal and offshore environments. We report on five G2 Slocum glider deployments in the northwestern Gulf during the spring and summer of 2015. The gliders were deployed in shallow (20 m) and deep (greater than 1000 m) water for a total of about 200 days. During this time, the gliders encountered a variety of environmental conditions that impact the circulation, biology, chemistry of the shelf and slope. The shallow gliders encountered coastal waters influenced by extensive flooding in terrestrial Texas that vertically stratified the water-column and was coincident with sub-pycnocline low dissolved oxygen concentration, at times below the hypoxic threshold of 2 mg/L, and elevated CDOM concentrations. These gliders also reveal high spatial variability with bottom boundary oxygen and biomass scales on the order of a few kilometers. The deep gliders were tasked to investigate shelf/slope exchange at two locations 94W and 91W. The western glider encountered a mature mesoscale circulation eddy that was actively weakening. The eastern glider simultaneously encountered a freshly separated Loop Current eddy. The vertical structure of hydrographic and dissolved oxygen parameters shows significant and distinguishable variability in each feature. The vertical structure of both features show significant departures from that which is expected based on sea surface height determined from satellite altimetry. Additionally, glider observations are compared to operational high-resolution regional numerical model output. These observations emphasize the importance of direct observations over satellite-derived products for applications that include upper ocean heat content for hurricane intensification and vertical mixing and ventilation of the oceanic interior.

Optimizations on supply and distribution of dissolved oxygen in constructed wetlands: A review.

PubMed

Liu, Huaqing; Hu, Zhen; Zhang, Jian; Ngo, Huu Hao; Guo, Wenshan; Liang, Shuang; Fan, Jinlin; Lu, Shaoyong; Wu, Haiming

2016-08-01

Dissolved oxygen (DO) is one of the most important factors that can influence pollutants removal in constructed wetlands (CWs). However, problems of insufficient oxygen supply and inappropriate oxygen distribution commonly exist in traditional CWs. Detailed analyses of DO supply and distribution characteristics in different types of CWs were introduced. It can be concluded that atmospheric reaeration (AR) served as the promising point on oxygen intensification. The paper summarized possible optimizations of DO in CWs to improve its decontamination performance. Process (tidal flow, drop aeration, artificial aeration, hybrid systems) and parameter (plant, substrate and operating) optimizations are particularly discussed in detail. Since economic and technical defects are still being cited in current studies, future prospects of oxygen research in CWs terminate this review. Copyright © 2016. Published by Elsevier Ltd.

Shallow Remineralization in the Sargasso Sea Estimated from Seasonal Variations in Oxygen and Dissolved Inorganic Carbon

NASA Technical Reports Server (NTRS)

Ono, S.; Ennyu, A.; Najjar, R. G.; Bates, N.

1998-01-01

A diagnostic model of the mean annual cycles of dissolved inorganic carbon (DIC) and oxygen below the mixed layer at the Bermuda Atlantic Time-series Study (BATS) site is presented and used to estimate organic carbon remineralization in the seasonal thermocline. The model includes lateral and vertical advection as well as vertical, diffusion. Very good agreement is found for the remineralization estimates based on oxygen and DIC. Net remineralization averaged from mid-spring to early fall is found to be a maximum between 120 and 140 in. Remineralization integrated between 100 (the compensation depth) and 250 m during this period is estimated to be about 1 mol C/sq m. This flux is consistent with independent estimates of the loss of particulate and dissolved organic carbon.

In-situ sediment oxygen demand rates in Hammonton Creek, Hammonton, New Jersey, and Crosswicks Creek, near New Egypt, New Jersey, August-October 2009

USGS Publications Warehouse

Wilson, Timothy P.

2014-01-01

Sediment oxygen demand rates were measured in Hammonton Creek, Hammonton, New Jersey, and Crosswicks Creek, near New Egypt, New Jersey, during August through October 2009. These rates were measured as part of an ongoing water-quality monitoring program being conducted in cooperation with the New Jersey Department of Environmental Protection. Oxygen depletion rates were measured using in-situ test chambers and a non-consumptive optical electrode sensing technique for measuring dissolved oxygen concentrations. Sediment oxygen demand rates were calculated on the basis of these field measured oxygen depletion rates and the temperature of the stream water at each site. Hammonton Creek originates at an impoundment, then flows through pine forest and agricultural fields, and receives discharge from a sewage-treatment plant. The streambed is predominantly sand and fine gravel with isolated pockets of organic-rich detritus. Sediment oxygen demand rates were calculated at four sites on Hammonton Creek and were found to range from -0.3 to -5.1 grams per square meter per day (g/m2/d), adjusted to 20 degrees Celsius. When deployed in pairs, the chambers produced similar values, indicating that the method was working as expected and yielding reproducible results. At one site where the chamber was deployed for more than 12 hours, dissolved oxygen was consumed linearly over the entire test period. Crosswicks Creek originates in a marshy woodland area and then flows through woodlots and pastures. The streambed is predominantly silt and clay with some bedrock exposures. Oxygen depletion rates were measured at three sites within the main channel of the creek, and the calculated sediment oxygen demand rates ranged from -0.33 to -2.5 g/m2/d, adjusted to 20 degrees Celsius. At one of these sites sediment oxygen demand was measured in both a center channel flowing area of a pond in the stream and in a stagnant non-flowing area along the shore of the pond where organic-rich bottom sediments had accumulated and lower dissolved oxygen concentration conditions existed in the water column. Dissolved oxygen concentrations in the center channel test chamber showed a constant slow decrease over the entire test period. Oxygen consumption in the test chamber at the near-shore location began rapidly and then slowed over time as oxygen became depleted in the chamber. Depending on the portion of the near-shore dissolved oxygen depletion curve used, calculated sediment oxygen demand rates ranged from as low as -0.03 g/m2/d to as high as -10 g/m2/d. The wide range of sediment oxygen demand rates indicates that care must be taken when extrapolating sediment oxygen demand rates between stream sites that have different bottom sediment types and different flow regimes.

Estimating flow rates to optimize winter habitat for centrarchid fish in Mississippi River (USA) backwaters

USGS Publications Warehouse

Johnson, Barry L.; Knights, Brent C.; Barko, John W.; Gaugush, Robert F.; Soballe, David M.; James, William F.

1998-01-01

The backwaters of large rivers provide winter refuge for many riverine fish, but they often exhibit low dissolved oxygen levels due to high biological oxygen demand and low flows. Introducing water from the main channel can increase oxygen levels in backwaters, but can also increase current velocity and reduce temperature during winter, which may reduce habitat suitability for fish. In 1993, culverts were installed to introduce flow to the Finger Lakes, a system of six backwater lakes on the Mississippi River, about 160 km downstream from Minneapolis, Minnesota. The goal was to improve habitat for bluegills and black crappies during winter by providing dissolved oxygen concentrations >3 mg/L, current velocities <1 cm/s, and temperatures >1°C. To achieve these conditions, we used data on lake volume and oxygen demand to estimate the minimum flow required to maintain 3 mg/L of dissolved oxygen in each lake. Estimated flows ranged from 0.02 to 0.14 m3/s among lakes. Data gathered in winter 1994 after the culverts were opened, indicated that the estimated flows met habitat goals, but that thermal stratification and lake morphometry can reduce the volume of optimal habitat created.

Process for oxidation of hydrogen halides to elemental halogens

DOEpatents

Lyke, Stephen E.

1992-01-01

An improved process for generating an elemental halogen selected from chlorine, bromine or iodine, from a corresponding hydrogen halide by absorbing a molten salt mixture, which includes sulfur, alkali metals and oxygen with a sulfur to metal molar ratio between 0.9 and 1.1 and includes a dissolved oxygen compound capable of reacting with hydrogen halide to produce elemental halogen, into a porous, relatively inert substrate to produce a substrate-supported salt mixture. Thereafter, the substrate-supported salt mixture is contacted (stage 1) with a hydrogen halide while maintaining the substrate-supported salt mixture during the contacting at an elevated temperature sufficient to sustain a reaction between the oxygen compound and the hydrogen halide to produce a gaseous elemental halogen product. This is followed by purging the substrate-supported salt mixture with steam (stage 2) thereby recovering any unreacted hydrogen halide and additional elemental halogen for recycle to stage 1. The dissolved oxygen compound is regenerated in a high temperature (stage 3) and an optical intermediate temperature stage (stage 4) by contacting the substrate-supported salt mixture with a gas containing oxygen whereby the dissolved oxygen compound in the substrate-supported salt mixture is regenerated by being oxidized to a higher valence state.

High sensitivity and accuracy dissolved oxygen (DO) detection by using PtOEP/poly(MMA-co-TFEMA) sensing film.

PubMed

Zhang, Ke; Zhang, Honglin; Wang, Ying; Tian, Yanqing; Zhao, Jiupeng; Li, Yao

2017-01-05

Fluorinated acrylate polymer has received great interest in recent years due to its extraordinary characteristics such as high oxygen permeability, good stability, low surface energy and refractive index. In this work, platinum octaethylporphyrin/poly(methylmethacrylate-co-trifluoroethyl methacrylate) (PtOEP/poly(MMA-co-TFEMA)) oxygen sensing film was prepared by the immobilizing of PtOEP in a poly(MMA-co-TFEMA) matrix and the technological readiness of optical properties was established based on the principle of luminescence quenching. It was found that the oxygen-sensing performance could be improved by optimizing the monomer ratio (MMA/TFEMA=1:1), tributylphosphate(TBP, 0.05mL) and PtOEP (5μg) content. Under this condition, the maximum quenching ratio I0/I100 of the oxygen sensing film is obtained to be about 8.16, Stern-Volmer equation is I0/I=1.003+2.663[O2] (R(2)=0.999), exhibiting a linear relationship, good photo-stability, high sensitivity and accuracy. Finally, the synthesized PtOEP/poly(MMA-co-TFEMA) sensing film was used for DO detection in different water samples. Copyright © 2016 Elsevier B.V. All rights reserved.

High sensitivity and accuracy dissolved oxygen (DO) detection by using PtOEP/poly(MMA-co-TFEMA) sensing film

NASA Astrophysics Data System (ADS)

Zhang, Ke; Zhang, Honglin; Wang, Ying; Tian, Yanqing; Zhao, Jiupeng; Li, Yao

2017-01-01

Fluorinated acrylate polymer has received great interest in recent years due to its extraordinary characteristics such as high oxygen permeability, good stability, low surface energy and refractive index. In this work, platinum octaethylporphyrin/poly(methylmethacrylate-co-trifluoroethyl methacrylate) (PtOEP/poly(MMA-co-TFEMA)) oxygen sensing film was prepared by the immobilizing of PtOEP in a poly(MMA-co-TFEMA) matrix and the technological readiness of optical properties was established based on the principle of luminescence quenching. It was found that the oxygen-sensing performance could be improved by optimizing the monomer ratio (MMA/TFEMA = 1:1), tributylphosphate(TBP, 0.05 mL) and PtOEP (5 μg) content. Under this condition, the maximum quenching ratio I0/I100 of the oxygen sensing film is obtained to be about 8.16, Stern-Volmer equation is I0/I = 1.003 + 2.663[O2] (R2 = 0.999), exhibiting a linear relationship, good photo-stability, high sensitivity and accuracy. Finally, the synthesized PtOEP/poly(MMA-co-TFEMA) sensing film was used for DO detection in different water samples.

Expansion of oxygen minimum zones may reduce available habitat for tropical pelagic fishes

NASA Astrophysics Data System (ADS)

Stramma, Lothar; Prince, Eric D.; Schmidtko, Sunke; Luo, Jiangang; Hoolihan, John P.; Visbeck, Martin; Wallace, Douglas W. R.; Brandt, Peter; Körtzinger, Arne

2012-01-01

Climate model predictions and observations reveal regional declines in oceanic dissolved oxygen, which are probably influenced by global warming. Studies indicate ongoing dissolved oxygen depletion and vertical expansion of the oxygen minimum zone (OMZ) in the tropical northeast Atlantic Ocean. OMZ shoaling may restrict the usable habitat of billfishes and tunas to a narrow surface layer. We report a decrease in the upper ocean layer exceeding 3.5mll-1 dissolved oxygen at a rate of <=1myr-1 in the tropical northeast Atlantic (0-25°N, 12-30°W), amounting to an annual habitat loss of ~5.95×1013m3, or 15% for the period 1960-2010. Habitat compression and associated potential habitat loss was validated using electronic tagging data from 47 blue marlin. This phenomenon increases vulnerability to surface fishing gear for billfishes and tunas, and may be associated with a 10-50% worldwide decline of pelagic predator diversity. Further expansion of the Atlantic OMZ along with overfishing may threaten the sustainability of these valuable pelagic fisheries and marine ecosystems.

Identification of an Archean marine oxygen oasis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Riding, Dr Robert E; Fralick, Dr Philip; Liang, Liyuan

2014-01-01

The early Earth was essentially anoxic. A number of indicators suggest the presence of oxygenic photosynthesis 2700 3000 million years (Ma) ago, but direct evidence for molecular oxygen (O2) in seawater has remained elusive. Here we report rare earth element (REE) analyses of 2800 million year old shallowmarine limestones and deep-water iron-rich sediments at Steep Rock Lake, Canada. These show that the seawater from which extensive shallow-water limestones precipitated was oxygenated, whereas the adjacent deeper waters where iron-rich sediments formed were not. We propose that oxygen promoted limestone precipitation by oxidative removal of dissolved ferrous iron species, Fe(II), to insolublemore » Fe(III) oxyhydroxide, and estimate that at least 10.25 M oxygen concentration in seawater was required to accomplish this at Steep Rock. This agrees with the hypothesis that an ample supply of dissolved Fe(II) in Archean oceans would have hindered limestone formation. There is no direct evidence for the oxygen source at Steep Rock, but organic carbon isotope values and diverse stromatolites in the limestones suggest the presence of cyanobacteria. Our findings support the view that during the Archean significant oxygen levels first developed in protected nutrient-rich shallow marine habitats. They indicate that these environments were spatially restricted, transient, and promoted limestone precipitation. If Archean marine limestones in general reflect localized oxygenic removal of dissolved iron at the margins of otherwise anoxic iron-rich seas, then early oxygen oases are less elusive than has been assumed.« less

Water quality and streamflow characteristics, Raritan River Basin, New Jersey

USGS Publications Warehouse

Anderson, Peter W.; Faust, Samuel Denton

1974-01-01

The findings of a problem-oriented river-system investigation of the stream-quality and streamflow characteristics of the Raritan River basin (1,105 square miles or 2,862 square kilometers drainage area) are described. The investigation covers mainly the period 1955-72. Precipitation in the basin is classified as ample and averages 47 inches or 120 centimeters per year (3-5 inches or 8-12 centimeters per month). During the study period four general precipitation trends were noted: less than normalin 1955-61 and 1966-70; extreme drought in 1962-66; and above normal in 1971-72. Analyses of streamflow measurements at eight gaging stations indicate a general trend toward lower flows during the study period, which is attributed to generally lower than normal precipitation. Highest flows were observed in 1958, concurrent with maximum annual precipitation; whereas lowest flows were observed in 1965 during extreme drought conditions. Non-tidal streams in the basin are grouped into three general regions of similar chemical quality based upon predominant constituents and dissolved-solids concentration during low-flow conditions. The predominant cations in solution in all regions are calcium and magnesium (usually exceeding 60 percent of total cation content). In headwater streams of the North and South Branch Raritan Rivers, bicarbonate is the predominant anion; a combination of sulfate, chloride, and nitrate are the predominant anions in the other two regions. The dissolved-solids concentration of streams in areas little influenced by man's activities generally range from 40 to 200 mg/L. Those in areas influenced by man often range much higher sometimes exceeding 800 mg/L. Suspended-sediment yields in the basin range from 25 to 500 tons per square mile annually. The water quality of the Raritan River and most tributaries above Manville (784 square miles of 2,030 square kilometers drainage area) generally is good for most industrial, domestic, and recreational uses, although pollution has been reported locally in some areas. A comparison of chemical analyses of water collected at several sampling sites in the 1920's with more recent data, however, indicate that there has been a significant increase in sulfate, chloride, and nitrate ions transported per unit of streamflow. These increases reflect increased waste-water discharges and nutrients in agricultural runoff in the upper basin. Trends in the dissolved-solids and dissolved-oxygen concentation of water in the Raritan and MIllstone Rivers above their confluence at Manville are described. The dissolved solids of the Millstone River are shown to increase, particularly at low streamflows. For example, at a flow of 100 cubic feet per second (2.83 cubic meters per second) this river tansported 13 percent more dissolved solids in 1969-70 than it did in 1957-58. A similar trend, however, was not apparent on the Raritan River. This phenomenon is attributed to dilution provided since 1964 by upstream reservoir releases during low flows. With the exception of low-flow periods on the Raritan River, dissolved-oxygen concentrations showed little or no significant time trends at Manville on either the Raritan or Millstone River. An improvement in dissolved-oxygen content at flows lower than 100 cubic feet per second (2.83 cubic meters per second) is observed with time on the Raritan River. This improvement is attributed to generally better quality water and dilution of nonconservative pollutants by upstream reservoir releases during low flows. The Raritan River between Manville and Perth Amboy flows through a large urban and industrial complex. Much of this reach is tidal. Detrimental activities of man are reflected in higher concentrations of most constituents below Manville than those observed upstream. For example, between Manville and the head of tide near South Bound Brook, the maximum concentration of dissolved solids observed during the study period increased from 464 to 1,520 mg/L; orthophosphates from 0.93 to 2.3 mg/L; phenolic materials from 22 to 312 μg/L; and coliform bacteria from 13,300 to 100,000 colonies per 100 milliliters. A general deterioration in water quality with time in the river below Manville is demonstrated through comparisons of dissolved-oxygen and biochemical-oxygen demand data collected between the late 1920's and early 1970's. Several time-of-travel measurements within the basin are reported. These data provide reasonable estimates of the time required for soluble contaminants to pass through particular parts of the river system. For example, the peak concentration of a contaminant injected into the river system at Clinton at a flow of 100 cubic feet per second (2.83 cubic meters per second) would be expected to travel to the head of tide near South Bound Brook, about 34 miles (55 kilometers), in about 70 hours; but at a flow of 50 cubic feet per second (1.42 cubic meters per second) the traveltime would increase to about 125 hours.

Triple oxygen isotope composition of photosynthetic oxygen

NASA Astrophysics Data System (ADS)

van der Meer, Anne; Kaiser, Jan

2013-04-01

The measurement of biological production rates is essential for our understanding how marine ecosystems are sustained and how much CO2 is taken up through aquatic photosynthesis. Traditional techniques to measure marine production are laborious and subject to systematic errors. A biogeochemical approach based on triple oxygen isotope measurements in dissolved oxygen (O2) has been developed over the last few years, which allows the derivation of gross productivity integrated over the depth of the mixed layer and the time-scale of O2 gas exchange (Luz and Barkan, 2000). This approach exploits the relative 17O/16O and 18O/16O isotope ratio differences of dissolved O2 compared to atmospheric O2 to work out the rate of biological production. Two parameters are key for this calculation: the isotopic composition of dissolved O2 in equilibrium with air and the isotopic composition of photosynthetic oxygen. Recently, a controversy has emerged in the literature over these parameters (Kaiser, 2011) and one of the goals of this research is to provide additional data to resolve this controversy. In order to obtain more information on the isotopic signature of biological oxygen, laboratory experiments have been conducted to determine the isotopic composition of oxygen produced by different phytoplankton cultures.

A one-dimensional, steady-state, dissolved-oxygen model and waste-load assimilation study for Wildcat Creek, Howard County, Indiana

USGS Publications Warehouse

Crawford, Charles G.; Wilber, William G.; Peters, James G.

1979-01-01

The Indiana State Board of Health is developing a water-quality management plan that includes establishing limits for wastewater effluents discharged into Indiana streams. A digital model calibrated to conditions in Wildcat Creek was used to predict alternatives for future waste loadings that would be compatible with Indiana stream water-quality standards defined for two critical hydrologic conditions, summer and winter low flows. The model indicates that benthic-oxygen demand is the most significant factor affecting the dissolved-oxygen concentrations in Wildcat Creek during summer low flows. The Indiana stream dissolved-oxygen standard should not be violated if the Kokomo wastewater-treatment facility meets its current National Pollution Discharge Elimination System permit restrictions (average monthly 5-day biochemical-oxygen demand of 5 milligrams per liter and maximum weekly 5-day biochemical-oxygen demand of 7.5 milligrams per liter) and benthic-oxygen demand becomes negligible. Ammonia-nitrogen toxicity may also be a water-quality limitation in Wildcat Creek. Ammonia-nitrogen waste loads for the Kokomo wastewater-treatment facility, projected by the Indiana State Board of Health, will result in stream ammonia-nitrogen concentrations that exceed the State standard (2.5 milligrams per liter during summer months and 4.0 milligrams per liter during winter months). (Kosco-USGS)

Glucose concentration alters dissolved oxygen levels in liquid cultures of Beauveria bassiana and affects formation and bioefficacy of blastospores.

PubMed

Mascarin, Gabriel Moura; Jackson, Mark A; Kobori, Nilce Naomi; Behle, Robert W; Dunlap, Christopher A; Delalibera Júnior, Ítalo

2015-08-01

The filamentous fungus Beauveria bassiana is an economically important pathogen of numerous arthropod pests and is able to grow in submerged culture as filaments (mycelia) or as budding yeast-like blastospores. In this study, we evaluated the effect of dissolved oxygen and high glucose concentrations on blastospore production by submerged cultures of two isolates of B. bassiana, ESALQ1432 and GHA. Results showed that maintaining adequate dissolved oxygen levels coupled with high glucose concentrations enhanced blastospore yields by both isolates. High glucose concentrations increased the osmotic pressure of the media and coincided with higher dissolved oxygen levels and increased production of significantly smaller blastospores compared with blastospores produced in media with lower concentrations of glucose. The desiccation tolerance of blastospores dried to less than 2.6 % moisture was not affected by the glucose concentration of the medium but was isolate dependent. Blastospores of isolate ESALQ1432 produced in media containing 140 g glucose L(-1) showed greater virulence toward whitefly nymphs (Bemisia tabaci) as compared with blastospores produced in media containing 40 g glucose L(-1). These results suggest a synergistic effect between glucose concentration and oxygen availability on changing morphology and enhancing the yield and efficacy of blastospores of B. bassiana, thereby facilitating the development of a cost-effective production method for this blastospore-based bioinsecticide.

Smart oxygen cuvette for optical monitoring of dissolved oxygen in biological blood samples

NASA Astrophysics Data System (ADS)

Dabhi, Harish; Alla, Suresh Kumar; Shahriari, Mahmoud R.

2010-02-01

A smart Oxygen Cuvette is developed by coating the inner surface of a cuvette with oxygen sensitive thin film material. The coating is glass like sol-gel based sensor that has an embedded ruthenium compound in the glass film. The fluorescence of the ruthenium is quenched depending on the oxygen level. Ocean Optics phase fluorometer, NeoFox is used to measure this rate of fluorescence quenching and computes it for the amount of oxygen present. Multimode optical fibers are used for transportation of light from an LED source to cuvette and from cuvette to phase fluorometer. This new oxygen sensing system yields an inexpensive solution for monitoring the dissolved oxygen in samples for biological and medical applications. In addition to desktop fluorometers, smart oxygen cuvettes can be used with the Ocean Optics handheld Fluorometers, NeoFox Sport. The Smart Oxygen Cuvettes provide a resolution of 4PPB units, an accuracy of less than 5% of the reading, and 90% response in less than 10 seconds.

Transcriptome and Multivariable Data Analysis of Corynebacterium glutamicum under Different Dissolved Oxygen Conditions in Bioreactors.

PubMed

Sun, Yang; Guo, Wenwen; Wang, Fen; Peng, Feng; Yang, Yankun; Dai, Xiaofeng; Liu, Xiuxia; Bai, Zhonghu

2016-01-01

Dissolved oxygen (DO) is an important factor in the fermentation process of Corynebacterium glutamicum, which is a widely used aerobic microbe in bio-industry. Herein, we described RNA-seq for C. glutamicum under different DO levels (50%, 30% and 0%) in 5 L bioreactors. Multivariate data analysis (MVDA) models were used to analyze the RNA-seq and metabolism data to investigate the global effect of DO on the transcriptional distinction of the substance and energy metabolism of C. glutamicum. The results showed that there were 39 and 236 differentially expressed genes (DEGs) under the 50% and 0% DO conditions, respectively, compared to the 30% DO condition. Key genes and pathways affected by DO were analyzed, and the result of the MVDA and RNA-seq revealed that different DO levels in the fermenter had large effects on the substance and energy metabolism and cellular redox balance of C. glutamicum. At low DO, the glycolysis pathway was up-regulated, and TCA was shunted by the up-regulation of the glyoxylate pathway and over-production of amino acids, including valine, cysteine and arginine. Due to the lack of electron-acceptor oxygen, 7 genes related to the electron transfer chain were changed, causing changes in the intracellular ATP content at 0% and 30% DO. The metabolic flux was changed to rebalance the cellular redox. This study applied deep sequencing to identify a wealth of genes and pathways that changed under different DO conditions and provided an overall comprehensive view of the metabolism of C. glutamicum. The results provide potential ways to improve the oxygen tolerance of C. glutamicum and to modify the metabolic flux for amino acid production and heterologous protein expression.

The impact of dissolved oxygen on sulfate radical-induced oxidation of organic micro-pollutants: A theoretical study.

PubMed

Zhang, Rui; Wang, Xiaoxiang; Zhou, Lei; Liu, Zhu; Crump, Doug

2018-05-15

Sulfate radical (SO 4 .- )-induced oxidation is an important technology in advanced oxidation processes (AOPs) for the removal of pollutants. To date, few studies have assessed the effects of dissolved oxygen (DO) on the SO 4 .- -induced oxidation of organic micro-pollutants. In the present work, a quantum chemical calculation was used to investigate the influence of the external oxygen molecule on the Gibbs free energy (G pollutant ) and HOMO-LUMO gap (ΔE) of 15 organic micro-pollutants representing four chemical categories. Several thermodynamic and statistical models were combined with the data from the quantum chemical calculation to illustrate the impact of DO on the oxidation of organic micro-pollutants by SO 4 .- . Results indicated that the external oxygen molecule increased G pollutant of all studied chemicals, which implies DO has the potential to decrease the energy barrier of the SO 4 .- -induced oxidation and shift the chemical equilibrium of the reaction towards the side of products. From the perspective of kinetics, DO can accelerate the oxidation by decreasing ΔE of organic micro-pollutants. In addition, changes of G pollutant and ΔE of the SO 4 .- -induced oxidation were both significantly different between open-chain and aromatic chemicals, and these differences were partially attributed to the difference of polarizability of these two types of chemicals. Furthermore, we revealed that all changes of G pollutant and ΔE induced by DO were dependent on the DO content. Our study emphasizes the significance of DO on the oxidation of organic micro-pollutants by SO 4 .- , and also provides a theoretical method to study the effect of components in wastewater on removal of organic pollutants in AOPs. Copyright © 2018 Elsevier Ltd. All rights reserved.

Meta-omic signatures of microbial metal and nitrogen cycling in marine oxygen minimum zones

PubMed Central

Glass, Jennifer B.; Kretz, Cecilia B.; Ganesh, Sangita; Ranjan, Piyush; Seston, Sherry L.; Buck, Kristen N.; Landing, William M.; Morton, Peter L.; Moffett, James W.; Giovannoni, Stephen J.; Vergin, Kevin L.; Stewart, Frank J.

2015-01-01

Iron (Fe) and copper (Cu) are essential cofactors for microbial metalloenzymes, but little is known about the metalloenyzme inventory of anaerobic marine microbial communities despite their importance to the nitrogen cycle. We compared dissolved O2, NO3−, NO2−, Fe and Cu concentrations with nucleic acid sequences encoding Fe and Cu-binding proteins in 21 metagenomes and 9 metatranscriptomes from Eastern Tropical North and South Pacific oxygen minimum zones and 7 metagenomes from the Bermuda Atlantic Time-series Station. Dissolved Fe concentrations increased sharply at upper oxic-anoxic transition zones, with the highest Fe:Cu molar ratio (1.8) occurring at the anoxic core of the Eastern Tropical North Pacific oxygen minimum zone and matching the predicted maximum ratio based on data from diverse ocean sites. The relative abundance of genes encoding Fe-binding proteins was negatively correlated with O2, driven by significant increases in genes encoding Fe-proteins involved in dissimilatory nitrogen metabolisms under anoxia. Transcripts encoding cytochrome c oxidase, the Fe- and Cu-containing terminal reductase in aerobic respiration, were positively correlated with O2 content. A comparison of the taxonomy of genes encoding Fe- and Cu-binding vs. bulk proteins in OMZs revealed that Planctomycetes represented a higher percentage of Fe genes while Thaumarchaeota represented a higher percentage of Cu genes, particularly at oxyclines. These results are broadly consistent with higher relative abundance of genes encoding Fe-proteins in the genome of a marine planctomycete vs. higher relative abundance of genes encoding Cu-proteins in the genome of a marine thaumarchaeote. These findings highlight the importance of metalloenzymes for microbial processes in oxygen minimum zones and suggest preferential Cu use in oxic habitats with Cu > Fe vs. preferential Fe use in anoxic niches with Fe > Cu. PMID:26441925

Meta-omic signatures of microbial metal and nitrogen cycling in marine oxygen minimum zones.

PubMed

Glass, Jennifer B; Kretz, Cecilia B; Ganesh, Sangita; Ranjan, Piyush; Seston, Sherry L; Buck, Kristen N; Landing, William M; Morton, Peter L; Moffett, James W; Giovannoni, Stephen J; Vergin, Kevin L; Stewart, Frank J

2015-01-01

Iron (Fe) and copper (Cu) are essential cofactors for microbial metalloenzymes, but little is known about the metalloenyzme inventory of anaerobic marine microbial communities despite their importance to the nitrogen cycle. We compared dissolved O2, NO[Formula: see text], NO[Formula: see text], Fe and Cu concentrations with nucleic acid sequences encoding Fe and Cu-binding proteins in 21 metagenomes and 9 metatranscriptomes from Eastern Tropical North and South Pacific oxygen minimum zones and 7 metagenomes from the Bermuda Atlantic Time-series Station. Dissolved Fe concentrations increased sharply at upper oxic-anoxic transition zones, with the highest Fe:Cu molar ratio (1.8) occurring at the anoxic core of the Eastern Tropical North Pacific oxygen minimum zone and matching the predicted maximum ratio based on data from diverse ocean sites. The relative abundance of genes encoding Fe-binding proteins was negatively correlated with O2, driven by significant increases in genes encoding Fe-proteins involved in dissimilatory nitrogen metabolisms under anoxia. Transcripts encoding cytochrome c oxidase, the Fe- and Cu-containing terminal reductase in aerobic respiration, were positively correlated with O2 content. A comparison of the taxonomy of genes encoding Fe- and Cu-binding vs. bulk proteins in OMZs revealed that Planctomycetes represented a higher percentage of Fe genes while Thaumarchaeota represented a higher percentage of Cu genes, particularly at oxyclines. These results are broadly consistent with higher relative abundance of genes encoding Fe-proteins in the genome of a marine planctomycete vs. higher relative abundance of genes encoding Cu-proteins in the genome of a marine thaumarchaeote. These findings highlight the importance of metalloenzymes for microbial processes in oxygen minimum zones and suggest preferential Cu use in oxic habitats with Cu > Fe vs. preferential Fe use in anoxic niches with Fe > Cu.

Transcriptome and Multivariable Data Analysis of Corynebacterium glutamicum under Different Dissolved Oxygen Conditions in Bioreactors

PubMed Central

Sun, Yang; Guo, Wenwen; Wang, Fen; Peng, Feng; Yang, Yankun; Dai, Xiaofeng; Liu, Xiuxia; Bai, Zhonghu

2016-01-01

Dissolved oxygen (DO) is an important factor in the fermentation process of Corynebacterium glutamicum, which is a widely used aerobic microbe in bio-industry. Herein, we described RNA-seq for C. glutamicum under different DO levels (50%, 30% and 0%) in 5 L bioreactors. Multivariate data analysis (MVDA) models were used to analyze the RNA-seq and metabolism data to investigate the global effect of DO on the transcriptional distinction of the substance and energy metabolism of C. glutamicum. The results showed that there were 39 and 236 differentially expressed genes (DEGs) under the 50% and 0% DO conditions, respectively, compared to the 30% DO condition. Key genes and pathways affected by DO were analyzed, and the result of the MVDA and RNA-seq revealed that different DO levels in the fermenter had large effects on the substance and energy metabolism and cellular redox balance of C. glutamicum. At low DO, the glycolysis pathway was up-regulated, and TCA was shunted by the up-regulation of the glyoxylate pathway and over-production of amino acids, including valine, cysteine and arginine. Due to the lack of electron-acceptor oxygen, 7 genes related to the electron transfer chain were changed, causing changes in the intracellular ATP content at 0% and 30% DO. The metabolic flux was changed to rebalance the cellular redox. This study applied deep sequencing to identify a wealth of genes and pathways that changed under different DO conditions and provided an overall comprehensive view of the metabolism of C. glutamicum. The results provide potential ways to improve the oxygen tolerance of C. glutamicum and to modify the metabolic flux for amino acid production and heterologous protein expression. PMID:27907077

Ice Harbor Spillway Dissolved Gas Field Studies: Before and After Spillway Deflectors

DTIC Science & Technology

2016-07-01

Executive Summary The operation of spillways on the Columbia and Snake Rivers causes the absorption of atmospheric gases (chiefly nitrogen and oxygen) to...chiefly nitrogen and oxygen) to super- saturated levels. For many operations, the total dissolved gas (TDG) levels exceed state and National...powerhouse releases. However, these mass- balance calculations conclusively show that a substantial portion of the powerhouse discharge becomes entrained

Relative stress corrosion susceptibilities of alloys 690 and 600 in simulated boiling water reactor environments

NASA Astrophysics Data System (ADS)

Page, R. A.; McMinn, A.

1986-05-01

The relative susceptibilities of alloys 600 and 690 to intergranular stress corrosion cracking (IGSCC) in pure water and a simulated resin intrusion environment at 288 °C were evaluated. A combination of creviced and noncreviced slow-strain-rate, and precracked fracture mechanics tests were employed in the evaluation. Susceptibility was determined as a function of dissolved oxygen content, degree of sensitization, and crevice condition. The results indicated that alloy 600 was susceptible to various degrees of IGSCC in oxygen containing pure water when creviced, and immune to IGSCC when uncreviced. Alloy 690 was immune to IGSCC under all pure water conditions examined. Alloy 600 and alloy 690 were both susceptible to cracking in the simulated resin intrusion environment. Alloy 690, however, exhibited the greatest resistance to SCC of the two alloys.

Exploring the effects of black mangrove (Avicennia germinans) expansions on nutrient cycling in smooth cordgrass (Spartina alterniflora) marsh sediments of southern Louisiana, USA

NASA Astrophysics Data System (ADS)

Henry, K. M.; Twilley, R. R.

2011-12-01

Located at the northernmost extent of mangroves in the Gulf of Mexico, coastal Louisiana (LA) provides an excellent opportunity to study the effects of a climate-induced vegetation shift on nutrient cycling within an ecosystem. Climate throughout the Gulf Coast region is experiencing a general warming trend and scientists predict both hotter summers (+1.5 to 4 °C) and warmer winters (+1.5 to 5.5 °C) by 2100. Over the last two decades, mild winter temperatures have facilitated the expansion of black mangrove trees (Avicennia germinans) into the smooth cordgrass (Spartina alterniflora) along parts of the LA coast. Due to differences in morphology and physiology between these two species, the expansion of Avicennia has the potential to greatly alter sediment biogeochemistry, especially nutrient cycling. With such an extensive history of coastal nutrient enrichment and eutrophication in the Mississippi River delta, it is important to understand how nutrient cycling, retention, and removal in this region will be affected by this climate-induced vegetation expansion. We examined the effect of this species shift on porewater salinity, sulfide, and dissolved inorganic nutrient concentrations (nitrite, nitrate, ammonium, and phosphate) as well as sediment oxidation-reduction potential, bulk density, and nutrient content (carbon, nitrogen, phosphorus). We also measured net dinitrogen (N2:Ar), oxygen, and dissolved inorganic nutrient fluxes on intact, non-vegetated sediment cores collected from both Spartina and Avicennia habitats. Spartina sediments were more reducing, with higher concentrations of sulfides and ammonium. We found no significant difference between Spartina and Avicennia sediment dinitrogen, oxygen, or dissolved inorganic nutrient fluxes. Net dinitrogen fluxes for both habitat types were predominately positive, indicating higher rates of denitrification than nitrogen fixation at these sites. Sediments were primarily a nitrate sink, but functioned as both a source and sink of nitrite, ammonium, and phosphate depending on the season and light conditions. Further sediment analysis showed no significant difference in bulk density, carbon, nitrogen, or phosphorus content between Spartina and Avicennia sediments. Marine sediments high in bulk density and phosphorus content and low carbon and nitrogen content dominated the top several centimeters in both Spartina and Avicennia habitats. These surprising but reassuring results suggest that in a region where allochthonous sediment input dominates organic accretion from the primary producers, the climate-induced shift from Spartina to Avicennia will have little to no affect on littoral nutrient cycling.

Water-quality conditions in Upper Klamath Lake, Oregon, 2002-04

USGS Publications Warehouse

Wood, Tamara M.; Hoilman, Gene R.; Lindenberg, Mary K.

2006-01-01

Eleven (2002) to 14 (2003 and 2004) continuous water-quality monitors that measured pH, dissolved oxygen, temperature, and specific conductance, were placed in Upper Klamath Lake to support a telemetry tracking study of endangered adult shortnose and Lost River suckers. Samples for the analysis of chlorophyll a and nutrients were collected at a subset of the water-quality monitor sites in each year. The seasonal pattern in the occurrence of supersaturated dissolved oxygen concentrations and high pH associated with photosynthetic activity, as well as the undersaturated dissolved oxygen concentrations associated with oxygen demand through respiration and decay in excess of photosynthetic production, were well described by the dynamics of the massive blooms of Aphanizomenon flos aquae (AFA) that occur each year. Data from the continuous monitors provided a means to quantify the occurrence, duration, and spatial extent of water-quality conditions potentially harmful to fish (dissolved- oxygen concentration less than 4 milligrams per liter, pH greater than 9.7, and temperature greater than 28 degrees Celsius) in the northern part of the lake, where the preferred adult sucker habitat is found. There were few observations of temperature greater than 28 degrees Celsius, suggesting that temperature is not a significant source of chronic stress to fish, although its role in the spread of disease is harder to define. Observations of pH greater than 9.7 were common during times when the AFA bloom was growing rapidly, so pH may be a source of chronic stress to fish. Dissolved oxygen concentrations less than 4 milligrams per liter were common in all 3 years at the deeper sites, in the lower part of the water column and for short periods during the day. Less common were instances of widespread low dissolved oxygen, throughout the water column and persisting through the entire day, but this was the character of a severe low dissolved oxygen event (LDOE) that culminated in the start of a fish die-off in 2003. Documented evidence indicates that LDOEs played a role in three fish die-offs in the mid-1990s as well. In the historical context of 15 years of climate and water-quality data, 3 out of 4 of the recent fish die-off years, 1996, 1997, and 2003, were characterized by low winds and high temperatures in July or August coincident with the start of the die-off. High temperatures accelerate the oxygen demanding processes that lead to a LDOE. The role of low winds remains inconclusive, but it could include the development of stratification in the water column and/or the alteration of the wind-driven circulation pattern. At a site centrally located in the study area, die-off years could be successfully identified in the historical data by screening for water characterized by exceptionally low chlorophyll a concentration, exceptionally low dissolved oxygen concentration throughout the water column (not just near the bottom), and exceptionally high ammonia concentration and water temperature, just prior to or coincident with the start of a fish die-off. These conditions indicate that a severe decline in the AFA bloom and conversion of most of the organic matter into inorganic form had taken place.

Multi-scale approach to the environmental factors effects on spatio-temporal variability of Chironomus salinarius (Diptera: Chironomidae) in a French coastal lagoon

NASA Astrophysics Data System (ADS)

Cartier, V.; Claret, C.; Garnier, R.; Fayolle, S.; Franquet, E.

2010-03-01

The complexity of the relationships between environmental factors and organisms can be revealed by sampling designs which consider the contribution to variability of different temporal and spatial scales, compared to total variability. From a management perspective, a multi-scale approach can lead to time-saving. Identifying environmental patterns that help maintain patchy distribution is fundamental in studying coastal lagoons, transition zones between continental and marine waters characterised by great environmental variability on spatial and temporal scales. They often present organic enrichment inducing decreased species richness and increased densities of opportunist species like C hironomus salinarius, a common species that tends to swarm and thus constitutes a nuisance for human populations. This species is dominant in the Bolmon lagoon, a French Mediterranean coastal lagoon under eutrophication. Our objective was to quantify variability due to both spatial and temporal scales and identify the contribution of different environmental factors to this variability. The population of C. salinarius was sampled from June 2007 to June 2008 every two months at 12 sites located in two areas of the Bolmon lagoon, at two different depths, with three sites per area-depth combination. Environmental factors (temperature, dissolved oxygen both in sediment and under water surface, sediment organic matter content and grain size) and microbial activities (i.e. hydrolase activities) were also considered as explanatory factors of chironomid densities and distribution. ANOVA analysis reveals significant spatial differences regarding the distribution of chironomid larvae for the area and the depth scales and their interaction. The spatial effect is also revealed for dissolved oxygen (water), salinity and fine particles (area scale), and for water column depth. All factors but water column depth show a temporal effect. Spearman's correlations highlight the seasonal effect (temperature, dissolved oxygen in sediment and water) as well as the effect of microbial activities on chironomid larvae. Our results show that a multi-scale approach identifies patchy distribution, even when there is relative environmental homogeneity.

Responses of bluegills and black crappies to dissolved oxygen, temperature, and current in backwater lakes of the upper Mississippi River during winter

USGS Publications Warehouse

Knights, B.C.; Johnson, B.L.; Sandheinrich, M.B.

1995-01-01

We conducted a radiotelemetry study to examine the effects of dissolved oxygen (DO), water temperature, and current velocity on winter habitat selection by bluegills Lepomis macrochirus and black crappies Pomoxis nigromaculatus in the Finger Lakes backwater complex, Pool 5, on the upper Mississippi River. When DO was above 2 mg/L, both species selected areas with water temperature greater than 1 degree C and undetectable current. As dissolved oxygen concentrations fell below 2 mg/L, fish moved to areas with higher DO, despite water temperatures of 1 degree C and lower and current velocities of 1 cm/s. Areas with water temperature less than 1 degree C and current velocity greater than 1 cm/s were avoided. To incorporate the winter habitat requirements of bluegills and black crappies into habitat restoration projects, we recommend designs that allow the inflow of oxygenated water to maintain adequate DO without substantially decreasing temperature and increasing current velocity.

Striped bass, temperature, and dissolved oxygen: a speculative hypothesis for environmental risk

DOE Office of Scientific and Technical Information (OSTI.GOV)

Coutant, C.C.

1985-01-01

Striped bass Morone saxatilis has a paradoxical record of distribution and abundance, including population declines in coastal waters and variable success of freshwater introductions. This record is analyzed for consistency with a hypothesis that striped bass are squeezed between their thermal and dissolved oxygen preferences or requirements. A commonality among diverse field and laboratory observations supports an inherent thermal niche for the species that changes to lower temperatures as fish age. This shift can cause local conditions, especially warm surface strata and deoxygenated deep water, to be incompatible with the success of large fish. Crowding due to temperature preferences alonemore » or coupled with avoidance of low oxygen concentrations can lead to pathology and overfishing, which may contribute to population declines. Through a mixture of evidence and conjecture, the thermal niche-dissolved oxygen hypothesis is proposed as a unified perspective of the habitat requirements of the species that can aid in its study and management. 139 references, 12 figures.« less

The effects of temperature and aeration on the corrosion of A508III low alloy steel in boric acid solutions at 25-95 °C

NASA Astrophysics Data System (ADS)

Xiao, Qian; Lu, Zhanpeng; Chen, Junjie; Yao, Meiyi; Chen, Zhen; Ejaz, Ahsan

2016-11-01

The effects of temperature, solution composition and dissolved oxygen on the corrosion rate and electrochemical behavior of an A508III low alloy steel in boric acid solution with lithium hydroxide at 25-95 °C are investigated. In aerated solutions, increasing the boric acid concentration increases the corrosion rate and the anodic current density. The corrosion rate in deaerated solutions increases with increasing temperature. A corrosion rate peak value is found at approximately 75 °C in aerated solutions. Increasing temperature increases the oxygen diffusion coefficient, decreases the dissolved oxygen concentration, accelerates the hydrogen evolution reaction, and accelerates both the active dissolution and the film forming reactions. Increasing dissolved oxygen concentration does not significantly affect the corrosion rate at 50 and 60 °C, increases the corrosion rate at 70 and 80 °C, and decreases the corrosion rate at 87.5 and 95 °C in a high concentration boric acid solution with lithium hydroxide.

Daily and seasonal variability of pH, dissolved oxygen, temperature, and specific conductance in the Colorado River between the forebay of Glen Canyon, Dam and Lees Ferry, northeastern Arizona, 1998-99

USGS Publications Warehouse

Flynn, Marilyn E.; Hart, Robert J.; Marzolf, G. Richard; Bowser, Carl J.

2001-01-01

The productivity of the trout fishery in the tailwater reach of the Colorado River downstream from Glen Canyon Dam depends on the productivity of lower trophic levels. Photosynthesis and respiration are basic biological processes that control productivity and alter pH and oxygen concentration. During 1998?99, data were collected to aid in the documentation of short- and long-term trends in these basic ecosystem processes in the Glen Canyon reach. Dissolved-oxygen, temperature, and specific-conductance profile data were collected monthly in the forebay of Glen Canyon Dam to document the status of water chemistry in the reservoir. In addition, pH, dissolved-oxygen, temperature, and specific-conductance data were collected at five sites in the Colorado River tailwater of Glen Canyon Dam to document the daily, seasonal, and longitudinal range of variation in water chemistry that could occur annually within the Glen Canyon reach.

A one-dimensional, steady-state, dissolved-oxygen model and waste-load assimilation study for Sand Creek, Decatur County, Indiana

USGS Publications Warehouse

Wilber, William G.; Crawford, Charles G.; Peters, James G.

1979-01-01

A digital model calibrated to conditions in Sand Creek near Greensburg, Ind., was used to develop alternatives for future waste loadings that would be compatible with Indiana stream water-quality standards defined for two critical hydrologic conditions, summer and winter low flows. The only point-source waste load affecting Sand Creek in the vicinity of Greensburg is the Greensburg wastewater-treatment facility. Non-point, unrecorded waste loads seemed to be significant during three water-quality surveys done by the Indiana State Board of Health. Natural streamflow in Sand Creek during the summer and annual 7-day, 10-year low flow is zero so no benefit from dilution is provided. Effluent ammonia-nitrogen concentrations from the Greensburg wastewater-treatment facility will not meet Indiana water-quality standards during summer and winter low flows. To meet the water-quality standard the wastewater-effluent would be limited to a maximum total ammonia-nitrogen concentration of 2.5 mg/l for summer months (June through August) and 4.0 mg/l for winter months (November through March). Model simulations indicate that benthic-oxygen demand, nitrification, and the dissolved-oxygen concentration of the wastewater effluent are the most significant factors affecting the in-stream dissolved-oxygen concentration during summer low flows. The model predicts that with a benthic-oxygen demand of 1.5 grams per square meter per day at 20C the stream has no additional waste-load assimilative capacity. Present carbonaceous biochemical-oxygen demand loads from the Greensburg wastewater-treatment facility will not result in violations of the in-stream dissolved-oxygen standard (5 mg/l) during winter low flows. (Kosco-USGS)

Electrochemical Investigations on Graphene and Lithium Phthalocyanine as Catalysts for Reversible Oxygen Reduction Reaction in Li-O2 Cells

DTIC Science & Technology

2015-05-11

maintained at 1:1. For the preparation of RGO-PPY composite, 1 ml pyrrole (Aldrich) was dissolved in 10 ml 0.1 M HCl and 100 mg RGO was added. The mixture...4 °C, and then added drop-wise to the suspension consisting of RGO and pyrrole . The contents were stirred for 6 h to facilitate the oxidation of... pyrrole to PPY. The RGO- PPY (weight ratio 1:1) composite was separated by centrifugation, washed repeatedly with water and finally with ethanol. It was

Comparative analysis of the Corynebacterium glutamicum transcriptome in response to changes in dissolved oxygen levels.

PubMed

Liu, Xiuxia; Yang, Sun; Wang, Fen; Dai, Xiaofeng; Yang, Yankun; Bai, Zhonghu

2017-02-01

The dissolved oxygen (DO) level of a culture of Corynebacterium glutamicum (C. glutamicum) in a bioreactor has a significant impact on the cellular redox potential and the distribution of energy and metabolites. In this study, to gain a deeper understanding of the effects of DO on the metabolism of C. glutamicum, we sought to systematically explore the influence of different DO concentrations on genetic regulation and metabolism through transcriptomic analysis. The results revealed that after 20 h of fermentation, oxygen limitation enhanced the glucose metabolism, pyruvate metabolism and carbon overflow, and restricted NAD + availability. A high oxygen supply enhanced the TCA cycle and reduced glyoxylate metabolism. Several key genes involved in response of C. glutamicum to different oxygen concentrations were examined, which provided suggestions for target site modifications in developing optimized oxygen supply strategies. These data provided new insights into the relationship between oxygen supply and metabolism of C. glutamicum.

Comprehensive model of microalgae photosynthesis rate as a function of culture conditions in photobioreactors.

PubMed

Costache, T A; Acién Fernández, F Gabriel; Morales, M M; Fernández-Sevilla, J M; Stamatin, I; Molina, E

2013-09-01

In this paper, the influence of culture conditions (irradiance, temperature, pH, and dissolved oxygen) on the photosynthesis rate of Scenedesmus almeriensis cultures is analyzed. Short-run experiments were performed to study cell response to variations in culture conditions, which take place in changing environments such as outdoor photobioreactors. Experiments were performed by subjecting diluted samples of cells to different levels of irradiance, temperature, pH, and dissolved oxygen concentration. Results demonstrate the existence of photoinhibition phenomena at irradiances higher than 1,000 μE/m(2) s; in addition to reduced photosynthesis rates at inadequate temperatures or pH-the optimal values being 35 °C and 8, respectively. Moreover, photosynthesis rate reduction at dissolved oxygen concentrations above 20 mg/l is demonstrated. Data have been used to develop an integrated model based on considering the simultaneous influence of irradiance, temperature, pH, and dissolved oxygen. The model fits the experimental results in the range of culture conditions tested, and it was validated using data obtained by the simultaneous variation of two of the modified variables. Furthermore, the model fits experimental results obtained from an outdoor culture of S. almeriensis performed in an open raceway reactor. Results demonstrate that photosynthetic efficiency is modified as a function of culture conditions, and can be used to determine the proximity of culture conditions to optimal values. Optimal conditions found (T = 35 °C, pH = 8, dissolved oxygen concentration <20 mg/l) allows to maximize the use of light by the cells. The developed model is a powerful tool for the optimal design and management of microalgae-based processes, especially outdoors, where the cultures are subject to daily culture condition variations.

The influence of dissolved oxygen level and medium on biofilm formation by Campylobacter jejuni.

PubMed

Teh, Amy Huei Teen; Lee, Sui Mae; Dykes, Gary A

2017-02-01

Campylobacter jejuni survival in aerobic environments has been suggested to be mediated by biofilm formation. Biofilm formation by eight C. jejuni strains under both aerobic and microaerobic conditions in different broths (Mueller-Hinton (MH), Bolton and Brucella) was quantified. The dissolved oxygen (DO) content of the broths under both incubation atmospheres was determined. Biofilm formation for all strains was highest in MH broth under both incubation atmospheres. Four strains had lower biofilm formation in MH under aerobic as compared to microaerobic incubation, while biofilm formation by the other four strains did not differ under the 2 atm. Two strains had higher biofilm formation under aerobic as compared to microaerobic atmospheres in Bolton broth. Biofilm formation by all other strains in Bolton, and all strains in Brucella broth, did not differ under the 2 atm. Under aerobic incubation DO levels in MH > Brucella > Bolton broth. Under microaerobic conditions levels in MH = Brucella > Bolton broth. Levels of DO in MH and Brucella broth were lower under microaerobic conditions but those of Bolton did not differ under the 2 atm. Experimental conditions and especially the DO of broth media confound previous conclusions drawn about aerobic biofilm formation by C. jejuni. Copyright © 2016 Elsevier Ltd. All rights reserved.

Reprint of: Effects of solution degassing on solubility, crystal growth and dissolution-Case study: Salicylic acid in methanol

NASA Astrophysics Data System (ADS)

Seidel, J.; Ulrich, J.

2017-07-01

The influence of dissolved gases on the crystallization parameter solubility, MZW, growth and dissolution rates was investigated experimentally using degassed and non-degassed (air-saturated) solutions. The results of this study show that degassing has no effect on the solubility curve of the used model substance salicylic acid (SA) in methanol (MeOH). This reveals in the assumption that a thermodynamic effect of dissolved gases can be excluded. Growth rates were measured by means of a desupersaturation method and the results indicate that the growth rates of SA are not affected by degassing. The results of the dissolution rate measurements reveal a distinct decrease in dissolution rates for non-degassed solutions compared to degassed solutions, especially, at low temperature (10 °C). To explain this phenomenon the gas solubility, represented by oxygen, in MeOH in dependence on the SA concentration was estimated by means of Hansen Solubility Parameters (HSP) [1]. It was found that the oxygen solubility decreases with increasing SA content which explains the inhibition of crystal dissolution in non-degassed solution compared to degassed solution. Moreover, this kind of 'drowing-out' mechanism would not appear in growth rate measurements, where indeed no effect of degassing could be observed.

Fremont Lake, Wyoming - Preliminary survey of a large mountain lake: A section in Geological Survey research 1972, Chapter D

USGS Publications Warehouse

Rickert, David A.; Leopold, Luna Bergere

1972-01-01

Fremont Lake, at an altitude of 2,261 m, has an area of 20.61 km2 and a volume of 1.69 km3. The maximum depth is 185 m, which makes it the seventh deepest natural lake in the conterminous United States. Theoretical renewal time is 11.1 years. Temperature data for 1971 indicate that vernal circulation extended to a depth of less than 90 m. The summer heat income was 19,450 cal/cm2. The dissolved-oxygen curve is orthograde, with a slight metalimnetic maximum, and a tendency toward decreasing concentrations at depth. At 180 m, oxygen was at 80 percent of saturation in late July 1970. The lake has a remarkably low dissolved-solids content of 12.8 mg/l, making it one of the most dilute medium-sized lakes in the world. Detailed chemical data are given for the water column at three sites in the lake and for the influent and effluent streams. Net plankton included representatives of seven genera of phytoplankters and three genera of zooplankters. A reconnaissance indicated substantially no bacteriological contamination in the lake, but there was an appreciable amount in two minor streams in the vicinity of a summer-home colony.

Effects of solution degassing on solubility, crystal growth and dissolution-Case study: Salicylic acid in methanol

NASA Astrophysics Data System (ADS)

Seidel, J.; Ulrich, J.

2017-02-01

The influence of dissolved gases on the crystallization parameter solubility, MZW, growth and dissolution rates was investigated experimentally using degassed and non-degassed (air-saturated) solutions. The results of this study show that degassing has no effect on the solubility curve of the used model substance salicylic acid (SA) in methanol (MeOH). This reveals in the assumption that a thermodynamic effect of dissolved gases can be excluded. Growth rates were measured by means of a desupersaturation method and the results indicate that the growth rates of SA are not affected by degassing. The results of the dissolution rate measurements reveal a distinct decrease in dissolution rates for non-degassed solutions compared to degassed solutions, especially, at low temperature (10 °C). To explain this phenomenon the gas solubility, represented by oxygen, in MeOH in dependence on the SA concentration was estimated by means of Hansen Solubility Parameters (HSP) [1]. It was found that the oxygen solubility decreases with increasing SA content which explains the inhibition of crystal dissolution in non-degassed solution compared to degassed solution. Moreover, this kind of 'drowing-out' mechanism would not appear in growth rate measurements, where indeed no effect of degassing could be observed.

The Impact of Potassium Manganate (VII) on the Effectiveness of Coagulation in the Removal of Iron and Manganese from Groundwater with an Increased Content of Organic Substances

NASA Astrophysics Data System (ADS)

Krupińska, Izabela

2017-12-01

The article presents the results of studies concerning the impact of the method of Fe(II) ion oxidisation (dissolved oxygen and potassium manganate (VII)) on the effectiveness of coagulation in the removal of iron and manganese from groundwater with an increased content of organic substances. The efficiencies of two coagulants were compared: aluminium sulphate (VI) and polyaluminium chloride (Flokor 1.2A). Among the used methods of iron (II) oxidisation, the best effects have been achieved by potassium manganate (VII) because one of the oxidation products was manganese oxide (IV) precipitating from water. Better results in purifying the water were obtained with the use of a prehydrolysed coagulant Flokor 1.2 A than aluminium sulphate (VI).

Water resources data, Kansas, water year 2004

USGS Publications Warehouse

Putnam, J.E.; Schneider, D.R.

2005-01-01

Water-resources data for the 2004 water year for Kansas consist of records of stage, discharge, and water quality of streams; elevation and contents of lakes and reservoirs; and water levels of ground-water wells. This report contains records for water discharge at 155 complete-record gaging stations; elevation and contents at 17 lakes and reservoirs; water-quality records at 2 precipitation stations, water-level data at 14 observation wells; and records of specific conductance, pH, water temperature, dissolved oxygen, and turbidity at 16 gaging stations and 2 lakes with water-quality monitors. Also included are discharge data for 29 high-flow partial-record stations. These data represent that part of the National Water Information System collected by the U.S. Geological Survey in cooperation with local, State, and Federal agencies in Kansas.

Ancient Oceans Had Less Oxygen

ERIC Educational Resources Information Center

King, Angela G.

2004-01-01

The amount of dissolved oxygen in the oceans in the mid-Proterozoic period has evolutionary implications since essential trace metals are redox sensitive. The findings suggest that there is global lack of oxygen in seawater.

One-dimensional simulation of stratification and dissolved oxygen in McCook Reservoir, Illinois

USGS Publications Warehouse

Robertson, Dale M.

2000-01-01

As part of the Chicagoland Underflow Plan/Tunnel and Reservoir Plan, the U.S. Army Corps of Engineers, Chicago District, plans to build McCook Reservoir.a flood-control reservoir to store combined stormwater and raw sewage (combined sewage). To prevent the combined sewage in the reservoir from becoming anoxic and producing hydrogen sulfide gas, a coarse-bubble aeration system will be designed and installed on the basis of results from CUP 0-D, a zero-dimensional model, and MAC3D, a three-dimensional model. Two inherent assumptions in the application of MAC3D are that density stratification in the simulated water body is minimal or not present and that surface heat transfers are unimportant and, therefore, may be neglected. To test these assumptions, the previously tested, one-dimensional Dynamic Lake Model (DLM) was used to simulate changes in temperature and dissolved oxygen in the reservoir after a 1-in-100-year event. Results from model simulations indicate that the assumptions made in MAC3D application are valid as long as the aeration system, with an air-flow rate of 1.2 cubic meters per second or more, is operated while the combined sewage is stored in the reservoir. Results also indicate that the high biochemical oxygen demand of the combined sewage will quickly consume the dissolved oxygen stored in the reservoir and the dissolved oxygen transferred through the surface of the reservoir; therefore, oxygen must be supplied by either the rising bubbles of the aeration system (a process not incorporated in DLM) or some other technique to prevent anoxia.

Effects of flood control and other reservoir operations on the water quality of the lower Roanoke River, North Carolina

USGS Publications Warehouse

Garcia, Ana Maria

2012-01-01

The Roanoke River is an important natural resource for North Carolina, Virginia, and the Nation. Flood plains of the lower Roanoke River, which extend from Roanoke Rapids Dam to Batchelor Bay near Albemarle Sound, support a large and diverse population of nesting birds, waterfowl, freshwater and anadromous fish, and other wildlife, including threatened and endangered species. The flow regime of the lower Roanoke River is affected by a number of factors, including flood-management operations at the upstream John H. Kerr Dam and Reservoir. A three-dimensional, numerical water-quality model was developed to explore links between upstream flows and downstream water quality, specifically in-stream dissolved-oxygen dynamics. Calibration of the hydrodynamics and dissolved-oxygen concentrations emphasized the effect that flood-plain drainage has on water and oxygen levels, especially at locations more than 40 kilometers away from the Roanoke Rapids Dam. Model hydrodynamics were calibrated at three locations on the lower Roanoke River, yielding coefficients of determination between 0.5 and 0.9. Dissolved-oxygen concentrations were calibrated at the same sites, and coefficients of determination ranged between 0.6 and 0.8. The model has been used to quantify relations among river flow, flood-plain water level, and in-stream dissolved-oxygen concentrations in support of management of operations of the John H. Kerr Dam, which affects overall flows in the lower Roanoke River. Scenarios have been developed to mitigate the negative effects that timing, duration, and extent of flood-plain inundation may have on vegetation, wildlife, and fisheries in the lower Roanoke River corridor. Under specific scenarios, the model predicted that mean dissolved-oxygen concentrations could be increased by 15 percent by flow-release schedules that minimize the drainage of anoxic flood-plain waters. The model provides a tool for water-quality managers that can help identify options that improve water quality and protect the aquatic habitat of the Roanoke River.

Strategies for dephenolization of raw olive mill wastewater by means of Pleurotus ostreatus.

PubMed

Olivieri, Giuseppe; Russo, Maria Elena; Giardina, Paola; Marzocchella, Antonio; Sannia, Giovanni; Salatino, Piero

2012-05-01

The reduction of polyphenols content in olive mill wastewater (OMW) is a major issue in olive oil manufacturing. Although researchers have pointed out the potential of white-rot fungus in dephenolizing OMW, the results available in the literature mainly concern pretreated (sterilized) OMW. This paper deals with the reduction of polyphenols content in untreated OMW by means of a white-rot fungus, Pleurotus ostreatus. Dephenolization was performed both in an airlift bioreactor and in aerated flasks. The process was carried out under controlled non-sterile conditions, with different operating configurations (batch, continuous, biomass recycling) representative of potential industrial operations. Total organic carbon, polyphenols concentration, phenol oxidase activity, dissolved oxygen concentration, oxygen consumption rate, and pH were measured during every run. Tests were carried out with or without added nutrients (potato starch and potato dextrose) and laccases inducers (i.e., CuSO₄). OMW endogenous microorganisms were competing with P. ostreatus for oxygen during simultaneous fermentation. Dephenolization of raw OMW by P. ostreatus under single batch was as large as 70%. Dephenolization was still extensive even when biomass was recycled up to six times. OMW pre-aeration had to be provided under continuous operation to avoid oxygen consumption by endogenous microorganisms that might spoil the process. The role of laccases in the dephenolization process has been discussed. Dephenolization under batch conditions with biomass recycling and added nutrients proved to be the most effective configuration for OMW polyphenols reduction in industrial plants (42-68% for five cycles).

Bioavailability of dissolved organic nitrogen (DON) in wastewaters from animal feedlots and storage lagoons

USDA-ARS?s Scientific Manuscript database

Dissolved organic nitrogen (DON) transport from animal agriculture to surface waters can lead to eutrophication and dissolved oxygen depletion. Biodegradable DON (BDON) is a portion of DON that is mineralized by bacteria while bioavailable DON (ABDON) is utilized by bacteria and/or algae. This stu...

Demonstration and Commercialization of the Sediment Ecosystem Assessment Protocol: Project ER-201130 Environmental Restoration Project

DTIC Science & Technology

2017-01-01

65 5-15. Dissolved oxygen and temperature data from T = 34 month (2015) post-remedy...Continuous measurements of dissolved oxygen and temperature in SEA Ring chambers placed at 3-meter depth at Chollas Creek mouth (CC1-B) and adjacent to...which the organisms would be exposed, such as salinity and temperature . This action provided valuable data to determine if any effects observed were

Effect of nitrate concentration on filamentous bulking under low level of dissolved oxygen in an airlift inner circular anoxic-aerobic incorporate reactor.

PubMed

Su, Yiming; Zhang, Yalei; Zhou, Xuefei; Jiang, Ming

2013-09-01

This laboratory research investigated a possible cause of filamentous bulking under low level of dissolved oxygen conditions (dissolved oxygen value in aerobic zone maintained between 0.6-0.8 mg O2/L) in an airlift inner-circular anoxic-aerobic reactor. During the operating period, it was observed that low nitrate concentrations affected sludge volume index significantly. Unlike the existing hypothesis, the batch tests indicated that filamentous bacteria (mainly Thiothrix sp.) could store nitrate temporarily under carbon restricted conditions. When nitrate concentration was below 4 mg/L, low levels of carbon substrates and dissolved oxygen in the aerobic zone stimulated the nitrate-storing capacity of filaments. When filamentous bacteria riched in nitrate reached the anoxic zone, where they were exposed to high levels of carbon but limited nitrate, they underwent denitrification. However, when nonfilamentous bacteria were exposed to similar conditions, denitrification was restrained due to their intrinsic nitrate limitation. Hence, in order to avoid filamentous bulking, the nitrate concentration in the return sludge (from aerobic zone to the anoxic zone) should be above 4 mg/L, or alternatively, the nitrate load in the anoxic zone should be kept at levels above 2.7 mg NO(3-)-N/g SS.

Oxygen and sulfur isotope systematics of sulfate produced by bacterial and abiotic oxidation of pyrite

USGS Publications Warehouse

Balci, N.; Shanks, Wayne C.; Mayer, B.; Mandernack, K.W.

2007-01-01

To better understand reaction pathways of pyrite oxidation and biogeochemical controls on ??18O and ??34S values of the generated sulfate in acid mine drainage (AMD) and other natural environments, we conducted a series of pyrite oxidation experiments in the laboratory. Our biological and abiotic experiments were conducted under aerobic conditions by using O2 as an oxidizing agent and under anaerobic conditions by using dissolved Fe(III)aq as an oxidant with varying ??18OH2O values in the presence and absence of Acidithiobacillus ferrooxidans. In addition, aerobic biological experiments were designed as short- and long-term experiments where the final pH was controlled at ???2.7 and 2.2, respectively. Due to the slower kinetics of abiotic sulfide oxidation, the aerobic abiotic experiments were only conducted as long term with a final pH of ???2.7. The ??34SSO4 values from both the biological and abiotic anaerobic experiments indicated a small but significant sulfur isotope fractionation (???-0.7???) in contrast to no significant fractionation observed from any of the aerobic experiments. Relative percentages of the incorporation of water-derived oxygen and dissolved oxygen (O2) to sulfate were estimated, in addition to the oxygen isotope fractionation between sulfate and water, and dissolved oxygen. As expected, during the biological and abiotic anaerobic experiments all of the sulfate oxygen was derived from water. The percentage incorporation of water-derived oxygen into sulfate during the oxidation experiments by O2 varied with longer incubation and lower pH, but not due to the presence or absence of bacteria. These percentages were estimated as 85%, 92% and 87% from the short-term biological, long-term biological and abiotic control experiments, respectively. An oxygen isotope fractionation effect between sulfate and water (??18 OSO4 s(-) H2 O) of ???3.5??? was determined for the anaerobic (biological and abiotic) experiments. This measured ??18 OSO42 - s(-) H2 O value was then used to estimate the oxygen isotope fractionation effects (??18 OSO42 - s(-) O2) between sulfate and dissolved oxygen in the aerobic experiments which were -10.0???, -10.8???, and -9.8??? for the short-term biological, long-term biological and abiotic control experiments, respectively. Based on the similarity between ??18OSO4 values in the biological and abiotic experiments, it is suggested that ??18OSO4 values cannot be used to distinguish biological and abiotic mechanisms of pyrite oxidation. The results presented here suggest that Fe(III)aq is the primary oxidant for pyrite at pH < 3, even in the presence of dissolved oxygen, and that the main oxygen source of sulfate is water-oxygen under both aerobic and anaerobic conditions. ?? 2007 Elsevier Ltd. All rights reserved.

[Distribution characteristics of dissolved oxygen and its affecting factors in the Pearl River Estuary during the summer of the extremely drought hydrological year 2011].

PubMed

Ye, Feng; Huang, Xiao-ping; Shi, Zhen; Liu, Qing-xi

2013-05-01

More and more attention has focused on assessing impacts of extreme hydrologic events on estuarine ecosystem under the background of climate change. Based on a summer cruise conducted in the Pearl River Estuary in 2011 (extreme drought event), we have investigated the spatial distribution of dissolved oxygen (DO) and its relationships to water column stability, nutrient concentrations, and organic matter; besides, the major reason which caused the oxygen depletion was discussed. Under the influence of the extreme drought event, low bottom water dissolved oxygen was apparent in regions characterized by great depths, with an oxygen minimum value of 1.38 mg x L(-1). Statistical analysis shows significant correlations among deltaDO, deltaT, deltaS and deltaPOC. A comparison was conducted to show the mechanisms of oxygen depletion during the summers of 1999, 2009 and 2011, respectively. The result indicates that prolonged residence time of water due to the extremely low discharge and the subsequently decomposition of organic substance are major factors causing the formation of hypoxia during the summer drought in 2011. Despite the changing nutrient and organic matter regime in the Pearl River Estuary, there was no apparent trend in the minimum values of DO over the past 2 decades.

Catchment scale molecular composition of hydrologically mobilized dissolved organic matter

NASA Astrophysics Data System (ADS)

Raeke, Julia; Lechtenfeld, Oliver J.; Oosterwoud, Marieke R.; Bornmann, Katrin; Tittel, Jörg; Reemtsma, Thorsten

2016-04-01

Increasing concentrations of dissolved organic matter (DOM) in rivers of temperate catchments in Europe and North Amerika impose new technical challenges for drinking water production. The driving factors for this decadal increase in DOM concentration are not conclusive and changes in annual temperatures, precipitation and atmospheric deposition are intensely discussed. It is known that the majority of DOM is released by few but large hydrologic events, mobilizing DOM from riparian wetlands for export by rivers and streams. The mechanisms of this mobilization and the resulting molecular composition of the released DOM may be used to infer long-term changes in the biogeochemistry of the respective catchment. Event-based samples collected over two years from streams in three temperate catchments in the German mid-range mountains were analyzed after solid-phase extraction of DOM for their molecular composition by ultra-high resolution mass spectrometry (FT-ICR MS). Hydrologic conditions, land use and water chemistry parameters were used to complement the molecular analysis. The molecular composition of the riverine DOM was strongly dependent on the magnitude of the hydrologic events, with unsaturated, oxygen-enriched compounds being preferentially mobilized by large events. This pattern is consistent with an increase in dissolved iron and aluminum concentrations. In contrast, the relative proportions of nitrogen and sulfur bearing compounds increased with an increased agricultural land use but were less affected by the mobilization events. Co-precipitation experiments with colloidal aluminum showed that unsaturated and oxygen-rich compounds are preferentially removed from the dissolved phase. The precipitated compounds thus had similar chemical characteristics as compared to the mobilized DOM from heavy rain events. Radiocarbon analyses also indicated that this precipitated fraction of DOM was of comparably young radiocarbon age. DOM radiocarbon from field samples showed that also the event-mobilized DOM had higher radiocarbon content. Overall, hydrology not only controls the quantity of exported carbon from temperate catchments but also strongly influences the molecular composition by mobilizing distinct compound classes in conjunction with dissolved iron and aluminum. From these results future compositional changes in temperate river DOM can be assessed, given an expected increase in the magnitude of hydrologic events, and technical advice for drinking water production may be inferred.

Dissolved oxygen and its response to eutrophication in a tropical black water river.

PubMed

Rixen, Tim; Baum, Antje; Sepryani, Harni; Pohlmann, Thomas; Jose, Christine; Samiaji, Joko

2010-08-01

The Siak is a typical, nutrient-poor, well-mixed, black water river in central Sumatra, Indonesia, which owes its brown color to dissolved organic matter (DOM) leached from surrounding, heavily disturbed peat soils. We measured dissolved organic carbon (DOC) and oxygen concentrations along the river, carried out a 36-h experiment in the province capital Pekanbaru and quantified organic matter and nutrient inputs from urban wastewater channels into the Siak. In order to consider the complex dynamic of oxygen in rivers, a box-diffusion model was used to interpret the measured data. The results suggest that the decomposition of soil derived DOM was the main factor influencing the oxygen concentration in the Siak which varied between approximately 100 and 140 micromol l(-1). Additional DOM input caused by wastewater discharges appeared to reduce the oxygen concentrations by approximately 20 micromol l(-1) during the peak-time in household water use in the early morning and in the early evening. Associated enhanced nutrient inputs appear to reduce the impact of the anthropogenic DOM by favoring the photosynthetic production of oxygen in the morning. A reduction of 20 micromol l(-1), which although perhaps not of great significance in Pekanbaru, has strong implications for wastewater management in the fast developing areas downstream Pekanbaru where oxygen concentrations rarely exceed 20 micromol l(-1). Copyright 2010 Elsevier Ltd. All rights reserved.

Dissolved oxygen: Chapter 6

USGS Publications Warehouse

Senn, David; Downing-Kunz, Maureen; Novick, Emily

2016-01-01

Dissolved oxygen (DO) concentration serves as an important indicator of estuarine habitat condition, because all aquatic macro-organisms require some minimum DO level to survive and prosper. The instantaneous DO concentration, measured at a specific location in the water column, results from a balance between multiple processes that add or remove oxygen (Figure 6.1): primary production produces O2; aerobic respiration in the water column and sediments consumes O2; abiotic or microbially-mediated biogeochemical reactions utilize O2 as an oxidant (e.g., oxidation of ammonium, sulfide, and ferrous iron); O2 exchange occurs across the air:water interface in response to under- or oversaturated DO concentrations in the water column; and water currents and turbulent mixing transport DO into and out of zones in the water column. If the oxygen loss rate exceeds the oxygen production or input rate, DO concentration decreases. When DO losses exceed production or input over a prolonged enough period of time, hypoxia ((<2-3 mg/L) or anoxia can develop. Persistent hypoxia or anoxia causes stress or death in aquatic organism populations, or for organisms that can escape a hypoxic or anoxic area, the loss of habitat. In addition, sulfide, which is toxic to aquatic organisms and causes odor problems, escapes from sediments under low oxygen conditions. Low dissolved oxygen is a common aquatic ecosystem response to elevated organic

Coupling of methylmercury uptake with respiration and water pumping in freshwater tilapia Oreochromis niloticus.

PubMed

Wang, Rui; Wong, Ming-Hung; Wang, Wen-Xiong

2011-09-01

The relationships among the uptake of toxic methylmercury (MeHg) and two important fish physiological processes-respiration and water pumping--in the Nile tilapia (Oreochromis niloticus) were explored in the present study. Coupled radiotracer and respirometric techniques were applied to measure simultaneously the uptake rates of MeHg, water, and oxygen under various environmental conditions (temperature, dissolved oxygen level, and water flow). A higher temperature enhanced MeHg influx and the oxygen consumption rate but had no effect on the water uptake, indicating the influence of metabolism on MeHg uptake. The fish showed a high tolerance to hypoxia, and the oxygen consumption rate was not affected until the dissolved oxygen concentration decreased to extremely low levels (below 1 mg/L). The MeHg and water uptake rates increased simultaneously as the dissolved oxygen level decreased, suggesting the coupling of water flux and MeHg uptake. The influence of fish swimming performance on MeHg uptake was also investigated for the first time. Rapidly swimming fish showed significantly higher uptake rates of MeHg, water, and oxygen, confirming the coupling relationships among respiration, water pumping, and metal uptake. Moreover, these results support that MeHg uptake is a rate-limiting process involving energy. Our study demonstrates the importance of physiological processes in understanding mercury bioaccumulation in fluctuating aquatic environments. Copyright © 2011 SETAC.

Microfluidic device coupled with a microfabricated oxygen electrode for the measurement of bactericidal activity of neutrophil-like cells.

PubMed

Yamagishi, Anna; Tanabe, Koji; Yokokawa, Masatoshi; Morimoto, Yuji; Kinoshita, Manabu; Suzuki, Hiroaki

2017-09-08

A microfluidic device coupled with a microfabricated Clark-type oxygen electrode was used to measure the bactericidal activity of neutrophil-like cells differentiated from HL-60 cells. The neutrophil-like cells and Escherichia coli (E. coli) cells were cultured in the same medium, which was introduced into the flow channel of the device. Changes in the respiratory activity of E. coli were measured as changes in the consumption of dissolved oxygen. As the activity of the neutrophil-like cells increased, the rate of elimination of E. coli increased. The accompanying decrease in the number of E. coli reduced the consumption of dissolved oxygen. The changes were actually observed as changes in generated current. A distinct difference in changes in dissolved oxygen concentrations was observed between E. coli cells co-incubated with IFN-γ-activated or non-activated neutrophil-like cells. The required sample volume was less than 10 μL, and results could be obtained within 1-2 h. The device may be useful for the assessment of psychological stresses that affect the activity of neutrophils. Copyright © 2017 Elsevier B.V. All rights reserved.

Preservation of tumour oxygen after hyperbaric oxygenation monitored by magnetic resonance imaging

PubMed Central

Kinoshita, Y; Kohshi, K; Kunugita, N; Tosaki, T; Yokota, A

1999-01-01

Hyperbaric oxygen (HBO) has been proposed to reduce tumour hypoxia by increasing the dissolved molecular oxygen in tissue. Using a non-invasive magnetic resonance imaging (MRI) technique, we monitored the changes in MRI signal intensity after HBO exposure because dissolved paramagnetic molecular oxygen itself shortens the T1 relation time. SCCVII tumour cells transplanted in mice were used. The molecular oxygen-enhanced MR images were acquired using an inversion recovery-preparation fast low angle shot (IR-FLASH) sequence sensitizing the paramagnetic effects of molecular oxygen using a 4.7 tesla MR system. MR signal of muscles decreased rapidly and returned to the control level within 40 min after decompression, whereas that of tumours decreased gradually and remained at a high level 60 min after HBO exposure. In contrast, the signal from the tumours in the normobaric oxygen group showed no significant change. Our data suggested that MR signal changes of tumours and muscles represent an alternation of extravascular oxygenation. The preserving tumour oxygen concentration after HBO exposure may be important regarding adjuvant therapy for cancer patients. © 2000 Cancer Research Campaign PMID:10638972

Feasibility Study and Environmental Impact Statement, Oakland Inner Harbor, California, Deep-Draft Navigation.

DTIC Science & Technology

1983-06-01

cl~. 0 I ~Ix *~ S I F (V () m C Y wI 0 C. -d concentrations of dissolved oxygen, heavy metals , petrolum hydrocarbons, pesticides, and turbidity...effects at the dredged and disposal sites under consideration. Water quality parameters of concern include: concentrations of dissolved oxygen, heavy ... metals , petroleum hydrocarbons and pesticides. Some groundwater has been pumped from wells penetrating the Meritt Sand. Brackish water of limited use

The effects of swimming exercise and dissolved oxygen on growth performance, fin condition and precocious maturation of early-rearing Atlantic salmon Salmo salar

USDA-ARS?s Scientific Manuscript database

Atlantic salmon fry were stocked into twelve circular 0.5 m3 tanks in a flow-through system and exposed to either high (1.5-2 body-lengths per second, or BL/s) or low (less than 0.5 BL/s) swimming speeding and high (100% saturation) or low (70% saturation) dissolved oxygen (DO) while being raised fr...

Iron and sulfur in the pre-biologic ocean

NASA Technical Reports Server (NTRS)

Walker, J. C.; Brimblecombe, P.

1985-01-01

Tentative geochemical cycles for the pre-biologic Earth are developed by comparing the relative fluxes of oxygen, dissolved iron, and sulfide to the atmosphere and ocean. The flux of iron is found to exceed both the oxygen and the sulfide fluxes. Because of the insolubility of iron oxides and sulfides the implication is that dissolved iron was fairly abundant and that oxygen and sulfide were rare in the atmosphere and ocean. Sulfate, produced by the oxidation of volcanogenic sulfur gases, was the most abundant sulfur species in the ocean, but its concentration was low by modern standards because of the absence of the river-borne flux of dissolved sulfate produced by oxidative weathering of the continents. These findings are consistent with the geologic record of the isotopic composition of sedimentary sulfates and sulfides. Except in restricted environments, the sulfur metabolism of the earliest organisms probably involved oxidized sulfur species not sulfide.

Enhanced bioremediation of BTEX using immobilized nutrients: Field demonstration and monitoring

DOE Office of Scientific and Technical Information (OSTI.GOV)

Borden, R.C.; Goin, R.T.; Kao, C.M.

1996-12-01

A permeable barrier system was developed for controlling the migration of dissolved contaminant plumes in ground water. The barrier system consisted of a line of closely spaced wells installed perpendicular to the contaminant plume. Each well contained concrete briquets that released oxygen and nitrate at a controlled rate, enhancing the aerobic biodegradation of dissolved hydrocarbons in the downgradient aquifer. A full scale permeable barrier system was constructed at a gasoline-spill site near Leland, NC. Initially, increased dissolved oxygen and decreased benzene, toluene, ethylbenzene, and xylene isomer (BTEX) concentrations in the downgradient aquifer indicated that oxygen released from the remediation wellsmore » was enhancing biodegradation. Field tracer tests and soil analyses performed at the conclusion of the project indicated that the aquifer in the vicinity of the remediation wells was being clogged by precipitation from iron minerals.« less

Baseline assessment of physical characteristics, aquatic biota, and selected water-quality properties at the reach and mesohabitat scale for reaches of Big Cypress, Black Cypress, and Little Cypress Bayous, Big Cypress Basin, northeastern Texas, 2010–11

USGS Publications Warehouse

Braun, Christopher L.; Moring, James B.

2013-01-01

In the absence of flow during fall 2011, the reach at Black Cypress was reduced to four isolated pools, and the reach at Little Cypress was reduced to three isolated pools. Dissolved oxygen, temperature, pH, and specific conductance data were collected from the pools because it was hypothesized that these conditions would be the most limiting with respect to aquatic life. Dissolved oxygen concentrations ranged from 0.58 milligrams per liter (mg/L) to 4.79 mg/L at Black Cypress and from 0.24 mg/L to 5.33 mg/L at Little Cypress; both sites exhibited a stratified pattern in dissolved oxygen concentrations along transect lines, but the pattern was less pronounced at Black Cypress.

The use of dissolved oxygen-controlled, fed-batch aerobic cultivation for recombinant protein subunit vaccine manufacturing.

PubMed

Farrell, Patrick; Sun, Jacob; Champagne, Paul-Philippe; Lau, Heron; Gao, Meg; Sun, Hong; Zeiser, Arno; D'Amore, Tony

2015-11-27

A simple "off-the-shelf" fed-batch approach to aerobic bacterial cultivation for recombinant protein subunit vaccine manufacturing is presented. In this approach, changes in the dissolved oxygen levels are used to adjust the nutrient feed rate (DO-stat), so that the desired dissolved oxygen level is maintained throughout cultivation. This enables high Escherichia coli cell densities and recombinant protein titers. When coupled to a kLa-matched scale-down model, process performance is shown to be consistent at the 2L, 20L, and 200L scales for two recombinant E. coli strains expressing different protein subunit vaccine candidates. Additionally, by mining historical DO-stat nutrient feeding data, a method to transition from DO-stat to a pre-determined feeding profile suitable for larger manufacturing scales without using feedback control is demonstrated at the 2L, 20L, and 200L scales. Copyright © 2015 Elsevier Ltd. All rights reserved.

Some factors influencing susceptibility of rainbow trout to the acute toxicity of an ethyl mercury phosphate formulation (Timsan)

USGS Publications Warehouse

Amend, Donald F.; Yasutake, William T.; Morgan, Reginald

1969-01-01

This study determined the influence of water temperature (55–68° F), dissolved oxygen (4–12 ppm), water hardness as CaCO3 (20–256 ppm), and chloride ions (to 2 mM) on the susceptibility of rainbow trout (Salmo gairdneri) to the acute toxicity of ethyl mercury phosphate (EMP). The fish were exposed for one hour to 0.125 ppm EMP, the active ingredient of Timsan, a commercial EMP formulation. The death rate because of the exposure to EMP increased with an increase in water temperature, a decrease in dissolved oxygen, and an increase in chloride ions; calcium appeared to have no effect. The effect of water temperature and dissolved oxygen was ascribed to changes in the respiration rate of the fish, and a chemical explanation is presented for the effect of chloride ions.

Water quality in Atlantic rainforest mountain rivers (South America): quality indices assessment, nutrients distribution, and consumption effect.

PubMed

Avigliano, Esteban; Schenone, Nahuel

2016-08-01

The South American Atlantic rainforest is a one-of-a-kind ecosystem considered as a biodiversity hotspot; however, in the last decades, it was intensively reduced to 7 % of its original surface. Water resources and water quality are one of the main goods and services this system provides to people. For monitoring and management recommendations, the present study is focused on (1) determining the nutrient content (nitrate, nitrite, ammonium, and phosphate) and physiochemical parameters (temperature, pH, electrical conductivity, turbidity, dissolved oxygen, and total dissolved solids) in surface water from 24 rainforest mountain rivers in Argentina, (2) analyzing the human health risk, (3) assessing the environmental distribution of the determined pollutants, and (4) analyzing water quality indices (WQIobj and WQImin). In addition, for total coliform bacteria, a dataset was used from literature. Turbidity, total dissolved solids, and nitrite (NO2 (-)) exceeded the guideline value recommended by national or international guidelines in several sampling stations. The spatial distribution pattern was analyzed by Principal Component Analysis and Factor Analysis (PCA/FA) showing well-defined groups of rivers. Both WQI showed good adjustment (R (2) = 0.89) and rated water quality as good or excellent in all sampling sites (WQI > 71). Therefore, this study suggests the use of the WQImin for monitoring water quality in the region and also the water treatment of coliform, total dissolved solids, and turbidity.

[Spatial-temporal distributions of dissolved inorganic carbon and its affecting factors in the Yellow River estuary].

PubMed

Guo, Xing-Sen; Lü, Ying-Chun; Sun, Zhi-Gao; Wang, Chuan-Yuan; Zhao, Quan-Sheng

2015-02-01

Estuary is an important area contributing to the global carbon cycle. In order to analyze the spatial-temporal distribution characteristics of the dissolved inorganic carbon (DIC) in the surface water of Yellow River estuary. Samples were collected in spring, summer, fall, winter of 2013, and discussed the correlation between the content of DIC and environmental factors. The results show that, the DIC concentration of the surface water in Yellow River estuary is in a range of 26.34-39.43 mg x L(-1), and the DIC concentration in freshwater side is higher than that in the sea side. In some areas where the salinity is less than 15 per thousand, the DIC concentration appears significant losses-the maximum loss is 20.46%. Seasonal distribution of performance in descending order is spring, fall, winter, summer. Through principal component analysis, it shows that water temperature, suspended solids, salinity and chlorophyll a are the main factors affecting the variation of the DIC concentration in surface water, their contribution rate is as high as 83% , and alkalinity, pH, dissolved organic carbon, dissolved oxygen and other factors can not be ignored. The loss of DIC in the low area is due to the calcium carbonate sedimentation. DIC presents a gradually increasing trend, which is mainly due to the effects of water retention time, temperature, outside input and environmental conditions.

[Effects of nitrogen addition and elevated CO2 concentration on soil dissolved organic carbon and nitrogen in rhizosphere and non-rhizosphere of Bothriochloa ischaemum].

PubMed

Xiao, Lie; Liu, Guo Bin; Li, Peng; Xue, Sha

2017-01-01

A pot experiment was conducted to study soil dissolved organic carbon (DOC) and dissolved organic nitrogen (DON) in the rhizosphere and non-rhizosphere of Bothriochloa ischaemum in loess hilly-gully region under the different treatments of CO 2 concentrations (400 and 800 μmol·mol -1 ) and nitrogen addition (0, 2.5, 5.0 g N·m -2 ·a -1 ). The results showed that eleva-ted CO 2 treatments had no significant effect on the contents of DOC, dissolved total nitrogen (DTN), DON, dissolved ammonium nitrogen (NH 4 + -N) and dissolved nitrate nitrogen (NO 3 - -N) in the soil of rhizosphere and non-rhizosphere of B. ischaemum. The contents of DTN, DON, and NO 3 - -N in the rhizosphere soil were significantly increased with the nitrogen application and the similar results of DTN and NO 3 - -N also were observed in the non-rhizosphere of B. ischaemum. Nitrogen application significantly decreased DOC/DON in the rhizosphere of B. ischaemum. The contents of DTN, NO 3 - -N and DON in the soil of rhizosphere were significantly lower than that in the non-rhizosphere soil, and DOC/DON was significantly higher in the rhizosphere soil than that in the non-rhizosphere soil. It indicated that short-term elevated CO 2 concentration had no significant influence on the contents of soil dissolved organic carbon and nitrogen. Simulated nitrogen deposition, to some extent, increased the content of soil dissolved nitrogen, but it was still insufficient to meet the demand of dissolved nitrogen for plant growing.

Magnitudes, nature, and effects of point and nonpoint discharges in the Chattahoochee River Basin, Atlanta to West Point Dam, Georgia

USGS Publications Warehouse

Stamer, J.K.; Cherry, Rodney N.; Faye, R.E.; Kleckner, R.L.

1979-01-01

During the period April 1975 to June 1978, the U.S. Geological Survey conducted a river-quality assessment of the Upper Chattahoochee River basin in Georgia. One objective of the study was to assess the magnitudes, nature, and effects of point and non-point discharges in the Chattahoochee River basin from Atlanta to the West Point Dam. On an average annual basis and during the storm period of March 1215, 1976, non-point-source loads for most constituents analyzed were larger than point-source loads at the Whitesburg station, located on the Chattahoochee River about 40 river miles downstream of Atlanta. Most of the non-point-source constituent loads in the Atlanta-to-Whitesburg reach were from urban areas. Average annual point-source discharges accounted for about 50 percent of the dissolved nitrogen, total nitrogen, and total phosphorus loads, and about 70 percent of the dissolved phosphorus loads at Whitesburg. During weekends, power generation at the upstream Buford Dam hydroelectric facility is minimal. Streamflow at the Atlanta station during dry-weather weekends is estimated to be about 1,200 ft3/s (cubic feet per second). Average daily dissolved-oxygen concentrations of less than 5.0 mg/L (milligrams per liter) occurred often in the river, about 20 river miles downstream from Atlanta during these periods from May to November. During a low-flow period, June 1-2, 1977, five municipal point sources contributed 63 percent of the ultimate biochemical oxygen demand, 97 percent of the ammonium nitrogen, 78 percent of the total nitrogen, and 90 percent of the total phosphorus loads at the Franklin station, at the upstream end of West Point Lake. Average daily concentrations of 13 mg/L of ultimate biochemical oxygen demand and 1.8 mg/L of ammonium nitrogen were observed about 2 river miles downstream from two of the municipal point sources. Carbonaceous and nitrogenous oxygen demands caused dissolved-oxygen concentrations between 4.1 and 5.0 mg/L to occur in a 22-mile reach of the river downstream from Atlanta. Nitrogenous oxygen demands were greater than carbonaceous oxygen demands in the reach from river mile 303 to 271, and carbonaceous demands were greater from river mile 271 to 235. The heat load from the Atkinson-McDonough thermoelectric power-plants caused a decrease in the dissolved-oxygen concentrations of about 0.2 mg/L. During a critical low-flow period, a streamflow at Atlanta of about 1,800 ft3/s, with present (1977) point-source flows of 185 ft3/s containing concentrations of 45 mg/L of ultimate biochemical oxygen demand and 15 mg/L of ammonium nitrogen, results in a computed minimum dissolved-oxygen concentration of 4.7 mg/L in the river downstream from Atlanta. In the year 2000, a streamflow at Atlanta of about 1,800 ft3/s with point-source flows of 373 ft3/s containing concentrations of 45 mg/L of ultimate biochemical oxygen demand and 5.0 mg/L of ammonium nitrogen, will result in a computed minimum dissolved-oxygen concentration of 5.0 mg/L. A streamflow of about 1,050 ft3/s at Atlanta in the year 2000 will result in a dissolved-oxygen concentration of 5.0 mg/L if point-source flows contain concentrations of 15 mg/L of ultimate biochemical oxygen demand and 5.0 mg/L of ammonium nitrogen. Phytoplankton concentrations in West Point Lake, about 70 river miles downstream from Atlanta, could exceed 3 million cells per milliliter during extended low-flow periods in the summer with present point- and non-point-source nitrogen and phosphorus loads. In the year 2000, phytoplankton concentrations in West Point Lake are not likely to exceed 700,000 cells per milliliter during extended low-flow periods in the summer, if phosphorus concentrations do not exceed 1.0 mg/L in point-source discharges.

The combined effects of carbon/nitrogen ratio, suspended biomass, hydraulic retention time and dissolved oxygen on nutrient removal in a laboratory-scale anaerobic-anoxic-oxic activated sludge biofilm reactor.

PubMed

Manu, D S; Kumar Thalla, Arun

2018-01-01

The current trend in sustainable development deals mainly with environmental management. There is a need for economically affordable, advanced treatment methods for the proper treatment and management of domestic wastewater containing excess nutrients (such as nitrogen and phosphorus) which can cause eutrophication. The reduction of the excess nutrient content of wastewater by appropriate technology is of much concern to the environmentalist. In the current study, a novel integrated anaerobic-anoxic-oxic activated sludge biofilm (A 2 O-AS-biofilm) reactor was designed and operated to improve the biological nutrient removal by varying reactor operating conditions such as carbon to nitrogen (C/N) ratio, suspended biomass, hydraulic retention time (HRT) and dissolved oxygen (DO). Based on various trials, it was seen that the A 2 O-AS-biofilm reactor achieved good removal efficiencies with regard to chemical oxygen demand (95.5%), total phosphorus (93.1%), ammonia nitrogen concentration (NH 4 + -N) (98%) and total nitrogen (80%) when the reactor was maintained at C/N ratio of 4, suspended biomass of 3 to 3.5 g/L, HRT of 10 h, and DO of 1.5 to 2.5 mg/L. Scanning electron microscopy (SEM) of suspended and attached biofilm showed a dense structure of coccus and bacillus bacteria with the diameter ranging from 0.3 to 1.2 μm. The Fourier transform infrared (FTIR) spectroscopy results indicated phosphorylated macromolecules and carbohydrates mix or bind with extracellular proteins in exopolysaccharides.

Improved vacuum-UV (VUV)-initiated photomineralization of organic compounds in water with a xenon excimer flow-through photoreactor (Xe2* lamp, 172 nm) containing an axially centered ceramic oxygenator.

PubMed

Oppenländer, Thomas; Walddörfer, Carsten; Burgbacher, Jens; Kiermeier, Martin; Lachner, Klaus; Weinschrott, Helga

2005-07-01

Xenon excimer (Xe2*) lamps can be used for the oxidation and mineralization of organic compounds in aqueous solution. This vacuum-ultraviolet (VUV) photochemical method is mainly based on the photochemically initiated homolysis of water that produces hydrogen atoms and hydroxyl radicals. The efficiency of substrate oxidation and mineralization is limited markedly due to the high absorbance of water at the emission maximum of the Xe2* lamp (lambda(max)=172 nm). This photochemical condition generates an extreme heterogeneity between the irradiated volume V(irr) and the non-irradiated ("dark") bulk solution. During VUV-initiated photomineralization of organic substrates, the fast scavenging of hydrogen atoms and of carbon-centered radicals by dissolved molecular oxygen produces a permanent oxygen deficit within V(irr) and adjacent compartments. Hence, at a constant photon flux the concentration of dissolved molecular oxygen within the zones of photo and thermal radical reactions limits the rate of mineralization, i.e. the rate of TOC diminution. Thus, a simple and convenient technique is presented that overcomes this limitation by injection of molecular oxygen (or air) into the irradiated volume by use of a ceramic oxygenator (aerator). The tube oxygenator was centered axially within the xenon excimer flow-through lamp. Consequently, the oxygen or air bubbles enhanced the transfer of dissolved molecular oxygen into the VUV-irradiated volume leading to an increased rate of mineralization of organic model compounds, e.g. 1-heptanol, benzoic acid and potassium hydrogen phthalate.

Mineralisation assays of some organic resources of aquatic systems.

PubMed

Bitar, A L; Bianchini, Júnior I

2002-11-01

Assays were carried out to evaluate the consumption of dissolved oxygen resulting from mineralisation processes in resources usually found in aquatic systems. They were also aimed at estimating the oxygen uptake rate of each investigated process. Experiments were conducted using substrates from 3 different places. A fixed amount of substrate was added to 5 litres of water from Lagoa do Infernão that was previously filtered with glass wool. After adding the substrates the bottles were aired and the amount of dissolved oxygen and the temperature were monitored for 55 days. The occurrence of anaerobic processes was avoided by reoxygenating the bottles. The experimental results were fitted to a first order kinetics model, from which the consumption of dissolved oxygen owing to mineralisation processes was obtained. The amount of oxygen uptake from the mineralisation processes appeared in the following decreasing order: Wolffia sp., Cabomba sp., Lemna sp., DOM (Dissolved Organic Matter), Salvinia sp., Scirpus cubensis, stem, Eichhornia azurea, sediment and humic compounds. The deoxygenation rates (day-1) were: 0.267 (humic compounds), 0.230 (Lemna sp.), 0.199 (E. azurea), 0.166 (S. cubensis), 0.132 (sediment), 0.126 (DOM), 0.093 (Cabomba sp.), 0.091 (stem), 0.079 (Salvinia sp. and Wolffia sp.). From these results, 2 groups of resources could be identified: the first one consists of detritus with higher amounts of labile (ready to use) compounds, which show a higher global oxygen uptake during the mineralisation process; the second one consists mainly of resources that show refracting characteristics. However, when the consumption rates are analysed it is noted that the mineralised parts of the refracting substrates can be easier to process than the labile fractions of the less refracting resources.

Topically delivered dissolved oxygen reduces inflammation and positively influences structural proteins in healthy intact human skin.

PubMed

Kellar, Robert S; Audet, Robert G; Roe, David F; Rheins, Lawrence A; Draelos, Zoe Diana

2013-06-01

As oxygen is essential for wound healing and there is limited diffusion across the stratum corneum into the epidermis, we wanted to evaluate whether the topical delivery of a total dissolved oxygen in dressing form on intact human subject skin would improve clinical and histologic skin functioning. Fifty normal, healthy subjects completed a pilot clinical evaluation to assess the efficacy and tolerability of a dissolved oxygen dressing (OxygeneSys™-Continuous) to improve the health and appearance of intact skin. Clinical analysis was performed on 50 subjects; histological and gene expression analysis was performed on 12 of the 50 subjects to assess the effect of the dissolved oxygen dressing. Clinical data demonstrate that the dressing is well tolerated, and several measures of skin health and integrity showed improvements compared with a control dressing site. Skin hydration measurements showed a statistically significant increase in skin hydration at 0-4, 4-8, and 0-8 weeks (P < 0.05 at each time point). The blinded clinical investigator's grading of desquamation, roughness, and skin texture show significant decreases from baseline to the 8-week time point (P < 0.05). The dressings were removed prior to the blinded clinical investigator's grading. These data were supported by the histological and gene expression studies, which showed a general reduction in inflammatory response markers and transcription products (IL-6, IL-8, TNF-alpha, MMP-1, and MMP-12), while facilitating a general increase in structural skin proteins (collagen I, elastin, and filaggrin). Additionally, p53 signals from biopsy samples support the clinical investigator's observations of no safety concerns. The data from this study demonstrate that the dressing has no deleterious effects and stimulates beneficial effects on intact, nonwounded skin. © 2013 Wiley Periodicals, Inc.

Sol-gel Synthesis, Photo- and Electrocatalytic Properties of Mesoporous TiO2 Modified with Transition Metal Ions

NASA Astrophysics Data System (ADS)

Smirnova, N.; Petrik, I.; Vorobets, V.; Kolbasov, G.; Eremenko, A.

2017-03-01

Mesoporous nanosized titania films modified with Co2+, Ni2+, Mn3+, and Cu2+ ions have been produced by templated sol-gel method and characterized by optical spectroscopy, X-ray diffraction (XRD), and Brunauer, Emmett, and Teller (BET) surface area measurement. Band gap energy and the position of flat band potentials were estimated by photoelectrochemical measurements. The films doped with transition metals possessed higher photocurrent quantum yield, as well as photo- and electrochemical activity compared to undoped samples. Mn+/TiO2 (M-Co, Ni, Mn, Cu) electrodes with low dopant content demonstrate high efficiency in electrocatalytic reduction of dissolved oxygen. Polarization curves of TiO2, TiO2/Ni2+, TiO2/Co2+/3+, and TiO2/Mn3+ electrodes contain only one current wave (oxygen reduction current). It means that reaction proceeds without the formation of an intermediate product H2O2.

A modified procedure for measuring oxygen-18 content of nitrate

NASA Astrophysics Data System (ADS)

Ahmed, M. A.; Aly, A. I. M.; Abdel Monem, N.; Hanafy, M.; Gomaa, H. E.

2012-11-01

SummaryMass spectrometric analysis of O-isotopic composition of nitrate has many potential applications in studies of environmental processes. Through this work, rapid, reliable, precise, broadly applicable, catalyst-free, low-priced and less labor intensive procedure for measuring δ18O of nitrate using Isotope Ratio Mass Spectrometer has been developed and implemented. The conditions necessary to effect complete nitrate recovery and complete removal of other oxygen containing anions and dissolved organic carbon (DOC) without scarifying the isotopic signature of nitrate were investigated. The developed procedure consists of two main parts: (1) wet chemistry train for extraction and purification of nitrate from the liquid matrix; (2) off-line pyrolysis of extracted nitrate salt with activated graphite at 550 °C for 30 min. The conditions necessary to effect complete nitrate recovery and complete removal of other oxygen containing compounds were investigated. Dramatic reduction in processing times needed for analysis of δ18O of nitrate at natural abundance level was achieved. Preservation experiments revealed that chloroform (99.8%) is an effective preservative. Isotopic contents of some selected nitrate salts were measured using the modified procedure and some other well established methods at two laboratories in Egypt and Germany. Performance assessment of the whole developed analytical train was made using internationally distributed nitrate isotopes reference materials and real world sample of initial zero-nitrate content. The uncertainty budget was evaluated using the graphical nested hierarchal approach. The obtained results proved the suitability for handling samples of complicated matrices. Reduction of consumables cost by about 80% was achieved.

Biodegradability of fluorinated fire-fighting foams in water.

PubMed

Bourgeois, A; Bergendahl, J; Rangwala, A

2015-07-01

Fluorinated fire-fighting foams may be released into the environment during fire-fighting activities, raising concerns due to the potential environmental and health impacts for some fluorinated organics. The current study investigated (1) the biodegradability of three fluorinated fire-fighting foams, and (2) the applicability of current standard measures used to assess biodegradability of fluorinated fire-fighting foams. The biodegradability of three fluorinated fire-fighting foams was evaluated using a 28-day dissolved organic carbon (DOC) Die-Away Test. It was found that all three materials, diluted in water, achieved 77-96% biodegradability, meeting the criteria for "ready biodegradability". Defluorination of the fluorinated organics in the foam during biodegradation was measured using ion chromatography. It was found that the fluorine liberated was 1-2 orders of magnitude less than the estimated initial amount, indicating incomplete degradation of fluorinated organics, and incomplete CF bond breakage. Published biodegradability data may utilize biochemical oxygen demand (BOD), chemical oxygen demand (COD), and total organic carbon (TOC) metrics to quantify organics. COD and TOC of four fluorinated compounds were measured and compared to the calculated carbon content or theoretical oxygen demand. It was found that the standard dichromate-based COD test did not provide an accurate measure of fluorinated organic content. Thus published biodegradability data using COD for fluorinated organics quantification must be critically evaluated for validity. The TOC measurements correlated to an average of 91% of carbon content for the four fluorinated test substances, and TOC is recommended for use as an analytical parameter in fluorinated organics biodegradability tests. Copyright © 2015 Elsevier Ltd. All rights reserved.

Low head oxygenator performance characterization for marine recirculating aquaculture systems

USDA-ARS?s Scientific Manuscript database

This study evaluated the effect of temperature (20 and 25 ºC), salinity (10, 15, and 20 ppt), and dissolved oxygen levels within low head oxygenator (LHO) outlet water on oxygen transfer efficiency (OTE) of LHOs for a planned marine recirculating aquaculture system (RAS). Test results indicated tha...

Oxygen requirement of separated hybrid catfish eggs

USDA-ARS?s Scientific Manuscript database

Channel catfish egg masses require hatchery water with over 7.8 ppm dissolved oxygen at 80° F (95% air saturation) to maintain maximum oxygen consumption as they near hatching. This concentration is called the critical oxygen requirement by scientists but for the purpose of this article we will call...

Arctic Deep Water Ferromanganese-Oxide Deposits Reflect the Unique Characteristics of the Arctic Ocean

NASA Astrophysics Data System (ADS)

Hein, James R.; Konstantinova, Natalia; Mikesell, Mariah; Mizell, Kira; Fitzsimmons, Jessica N.; Lam, Phoebe J.; Jensen, Laramie T.; Xiang, Yang; Gartman, Amy; Cherkashov, Georgy; Hutchinson, Deborah R.; Till, Claire P.

2017-11-01

Little is known about marine mineral deposits in the Arctic Ocean, an ocean dominated by continental shelf and basins semi-closed to deep-water circulation. Here, we present data for ferromanganese crusts and nodules collected from the Amerasia Arctic Ocean in 2008, 2009, and 2012 (HLY0805, HLY0905, and HLY1202). We determined mineral and chemical compositions of the crusts and nodules and the onset of their formation. Water column samples from the GEOTRACES program were analyzed for dissolved and particulate scandium concentrations, an element uniquely enriched in these deposits. The Arctic crusts and nodules are characterized by unique mineral and chemical compositions with atypically high growth rates, detrital contents, Fe/Mn ratios, and low Si/Al ratios, compared to deposits found elsewhere. High detritus reflects erosion of submarine outcrops and North America and Siberia cratons, transport by rivers and glaciers to the sea, and distribution by sea ice, brines, and currents. Uniquely high Fe/Mn ratios are attributed to expansive continental shelves, where diagenetic cycling releases Fe to bottom waters, and density flows transport shelf bottom water to the open Arctic Ocean. Low Mn contents reflect the lack of a mid-water oxygen minimum zone that would act as a reservoir for dissolved Mn. The potential host phases and sources for elements with uniquely high contents are discussed with an emphasis on scandium. Scandium sorption onto Fe oxyhydroxides and Sc-rich detritus account for atypically high scandium contents. The opening of Fram Strait in the Miocene and ventilation of the deep basins initiated Fe-Mn crust growth ˜15 Myr ago.

Arctic deep-water ferromanganese-oxide deposits reflect the unique characteristics of the Arctic Ocean

USGS Publications Warehouse

Hein, James; Konstantinova, Natalia; Mikesell, Mariah; Mizell, Kira; Fitzsimmons, Jessica N.; Lam, Phoebe; Jensen, Laramie T.; Xiang, Yang; Gartman, Amy; Cherkashov, Georgy; Hutchinson, Deborah; Till, Claire P.

2017-01-01

Little is known about marine mineral deposits in the Arctic Ocean, an ocean dominated by continental shelf and basins semi-closed to deep-water circulation. Here, we present data for ferromanganese crusts and nodules collected from the Amerasia Arctic Ocean in 2008, 2009, and 2012 (HLY0805, HLY0905, HLY1202). We determined mineral and chemical compositions of the crusts and nodules and the onset of their formation. Water column samples from the GEOTRACES program were analyzed for dissolved and particulate scandium concentrations, an element uniquely enriched in these deposits.The Arctic crusts and nodules are characterized by unique mineral and chemical compositions with atypically high growth rates, detrital contents, Fe/Mn ratios, and low Si/Al ratios, compared to deposits found elsewhere. High detritus reflects erosion of submarine outcrops and North America and Siberia cratons, transport by rivers and glaciers to the sea, and distribution by sea ice, brines, and currents. Uniquely high Fe/Mn ratios are attributed to expansive continental shelves, where diagenetic cycling releases Fe to bottom waters, and density flows transport shelf bottom water to the open Arctic Ocean. Low Mn contents reflect the lack of a mid-water oxygen minimum zone that would act as a reservoir for dissolved Mn. The potential host phases and sources for elements with uniquely high contents are discussed with an emphasis on scandium. Scandium sorption onto Fe oxyhydroxides and Sc-rich detritus account for atypically high scandium contents. The opening of Fram Strait in the Miocene and ventilation of the deep basins initiated Fe-Mn crust growth ∼15 Myr ago.

Changes in Ocean Heat, Carbon Content, and Ventilation: A Review of the First Decade of GO-SHIP Global Repeat Hydrography.

PubMed

Talley, L D; Feely, R A; Sloyan, B M; Wanninkhof, R; Baringer, M O; Bullister, J L; Carlson, C A; Doney, S C; Fine, R A; Firing, E; Gruber, N; Hansell, D A; Ishii, M; Johnson, G C; Katsumata, K; Key, R M; Kramp, M; Langdon, C; Macdonald, A M; Mathis, J T; McDonagh, E L; Mecking, S; Millero, F J; Mordy, C W; Nakano, T; Sabine, C L; Smethie, W M; Swift, J H; Tanhua, T; Thurnherr, A M; Warner, M J; Zhang, J-Z

2016-01-01

Global ship-based programs, with highly accurate, full water column physical and biogeochemical observations repeated decadally since the 1970s, provide a crucial resource for documenting ocean change. The ocean, a central component of Earth's climate system, is taking up most of Earth's excess anthropogenic heat, with about 19% of this excess in the abyssal ocean beneath 2,000 m, dominated by Southern Ocean warming. The ocean also has taken up about 27% of anthropogenic carbon, resulting in acidification of the upper ocean. Increased stratification has resulted in a decline in oxygen and increase in nutrients in the Northern Hemisphere thermocline and an expansion of tropical oxygen minimum zones. Southern Hemisphere thermocline oxygen increased in the 2000s owing to stronger wind forcing and ventilation. The most recent decade of global hydrography has mapped dissolved organic carbon, a large, bioactive reservoir, for the first time and quantified its contribution to export production (∼20%) and deep-ocean oxygen utilization. Ship-based measurements also show that vertical diffusivity increases from a minimum in the thermocline to a maximum within the bottom 1,500 m, shifting our physical paradigm of the ocean's overturning circulation.

Manipulation of Microenvironment with a Built-in Electrochemical Actuator in Proximity of a Dissolved Oxygen Microsensor

NASA Technical Reports Server (NTRS)

Kim, Chang-Soo; Lee, Cae-Hyang; Fiering, Jason O.; Ufer, Stefan; Scarantino, Charles W.; Nagle, H. Troy; Fiering, Jason O.; Ufer, Stefan; Nagle, H. Troy; Scarantino, Charles W.

2004-01-01

Abstract - Biochemical sensors for continuous monitoring require dependable periodic self- diagnosis with acceptable simplicity to check its functionality during operation. An in situ self- diagnostic technique for a dissolved oxygen microsensor is proposed in an effort to devise an intelligent microsensor system with an integrated electrochemical actuation electrode. With a built- in platinum microelectrode that surrounds the microsensor, two kinds of microenvironments, called the oxygen-saturated or oxygen-depleted phases, can be created by water electrolysis depending on the polarity. The functionality of the microsensor can be checked during these microenvironment phases. The polarographic oxygen microsensor is fabricated on a flexible polyimide substrate (Kapton) and the feasibility of the proposed concept is demonstrated in a physiological solution. The sensor responds properly during the oxygen-generating and oxygen- depleting phases. The use of these microenvironments for in situ self-calibration is discussed to achieve functional integration as well as structural integration of the microsensor system.

Transport of oxidized multi-walled carbon nanotubes through silica based porous media: influences of aquatic chemistry, surface chemistry, and natural organic matter.

PubMed

Yang, Jin; Bitter, Julie L; Smith, Billy A; Fairbrother, D Howard; Ball, William P

2013-12-17

This paper provides results from studies of the transport of oxidized multi-walled carbon nanotubes (O-MWCNTs) of varying surface oxygen concentrations under a range of aquatic conditions and through uniform silica glass bead media. In the presence of Na(+), the required ionic strength (IS) for maximum particle attachment efficiency (i.e., the critical deposition concentration, or CDC) increased as the surface oxygen concentration of the O-MWCNTs or pH increased, following qualitative tenets of theories based on electrostatic interactions. In the presence of Ca(2+), CDC values were lower than those with Na(+) present, but were no longer sensitive to surface oxygen content, suggesting that Ca(2+) impacts the interactions between O-MWCNTs and glass beads by mechanisms other than electrostatic alone. The presence of Suwannee River natural organic matter (SRNOM) decreased the attachment efficiency of O-MWCNTs in the presence of either Na(+) or Ca(2+), but with more pronounced effects when Na(+) was present. Nevertheless, low concentrations of SRNOM (<4 mg/L of dissolved organic carbon) were sufficient to mobilize all O-MWCNTs studied at CaCl2 concentrations as high as 10 mM. Overall, this study reveals that NOM content, pH, and cation type show more importance than surface chemistry in affecting O-MWCNTs deposition during transport through silica-based porous media.

Effect of filter media thickness on the performance of sand drying beds used for faecal sludge management.

PubMed

Manga, M; Evans, B E; Camargo-Valero, M A; Horan, N J

2016-12-01

The effect of sand filter media thickness on the performance of faecal sludge (FS) drying beds was determined in terms of: dewatering time, contaminant load removal efficiency, solids generation rate, nutrient content and helminth eggs viability in the dried sludge. A mixture of ventilated improved pit latrine sludge and septage in the ratio 1:2 was dewatered using three pilot-scale sludge drying beds with sand media thicknesses of 150, 250 and 350 mm. Five dewatering cycles were conducted and monitored for each drying bed. Although the 150 mm filter had the shortest average dewatering time of 3.65 days followed by 250 mm and 350 mm filters with 3.83 and 4.02 days, respectively, there was no significant difference (p > 0.05) attributable to filter media thickness configurations. However, there was a significant difference for the percolate contaminant loads in the removal and recovery efficiency of suspended solids, total solids, total volatile solids, nitrogen species, total phosphorus, chemical oxygen demand, dissolved chemical oxygen demand and biochemical oxygen demand, with the highest removal efficiency for each parameter achieved by the 350 mm filter. There were also significant differences in the nutrient content (NPK) and helminth eggs viability of the solids generated by the tested filters. Filtering media configurations similar to 350 mm have the greatest potential for optimising nutrient recovery from FS.

Environmental Conditions in a Carpathian Deep Sea Basin During the Period Preceding Oceanic Anoxic Event 2 - A Case Study from the Skole Nappe

NASA Astrophysics Data System (ADS)

Bąk, Krzysztof; Bąk, Marta; Górny, Zbigniew; Wolska, Anna

2015-01-01

Hemipelagic green clayey shales and thin muddy turbidites accumulated in a deep sea environment below the CCD in the Skole Basin, a part of the Outer Carpathian realm, during the Middle Cenomanian. The hemipelagites contain numerous radiolarians, associated with deep-water agglutinated foraminifera. These sediments accumulated under mesotrophic conditions with limited oxygen concentration. Short-term periodic anoxia also occurred during that time. Muddy turbidity currents caused deposition of siliciclastic and biogenic material, including calcareous foramini-fers and numerous sponge spicules. The preservation and diversity of the spicules suggests that they originate from disarticulation of moderately diversified sponge assemblages, which lived predominantly in the neritic-bathyal zone. Analyses of radiolarian ecological groups and pellets reflect the water column properties during the sedimentation of green shales. At that time, surface and also intermediate waters were oxygenated enough and sufficiently rich in nutri-ents to enable plankton production. Numerous, uncompacted pellets with nearly pristine radiolarian skeletons inside show that pelletization was the main factor of radiolarian flux into the deep basin floor. Partly dissolved skeletons indicate that waters in the Skole Basin were undersaturated in relation to silica content. Oxygen content might have been depleted in the deeper part of the water column causing periodic anoxic conditions which prevent rapid bacterial degra-dation of the pellets during their fall to the sea floor.

Water Resources Data, Kansas, Water Year 2001

USGS Publications Warehouse

Putnam, J.E.; Lacock, D.L.; Schneider, D.R.

2002-01-01

Water-resources data for the 2001 water year for Kansas consist of records of stage, discharge, and water quality of streams; elevation and contents of lakes and reservoirs; and water levels of ground-water wells. This report contains records for water discharge at 145 complete-record gaging stations; elevation and contents at 20 lakes and reservoirs; waterquality records at 2 precipitation stations, water-level data at 19 observation wells; and records of specific conductance, pH, water temperature, dissolved oxygen, and turbidity at 11 gaging stations. Also included are discharge data for 26 high-flow partial-record stations, miscellaneous onsite water-quality data collected at 140 stations, and suspended-sediment concentration for 12 stations. These data represent that part of the National Water Information System collected by the U.S. Geological Survey in cooperation with local, State, and Federal agencies in Kansas.

Water Resources Data, Kansas, Water Year 2002

USGS Publications Warehouse

Putnam, J.E.; Schneider, D.R.

2003-01-01

Water-resources data for the 2002 water year for Kansas consist of records of stage, discharge, and water quality of streams; elevation and contents of lakes and reservoirs; and water levels of ground-water wells. This report contains records for water discharge at 149 complete-record gaging stations; elevation and contents at 20 lakes and reservoirs; waterquality records at 2 precipitation stations, water-level data at 18 observation wells; and records of specific conductance, pH, water temperature, dissolved oxygen, and turbidity at 11 gaging stations. Also included are discharge data for 26 high-flow partial-record stations, miscellaneous onsite water-quality data collected at 142 stations, and suspended-sediment concentration for 12 stations. These data represent that part of the National Water Information System collected by the U.S. Geological Survey in cooperation with local, State, and Federal agencies in Kansas.

Water Resources Data, Kansas, Water Year 2000

USGS Publications Warehouse

Putnam, J.E.; Lacock, D.L.; Schneider, D.R.; Carlson, M.D.

2001-01-01

Water-resources data for the 2000 water year for Kansas consist of records of stage, discharge, and water quality of streams; elevation and contents of lakes and reservoirs; and water levels of ground-water wells. This report contains records for water discharge at 144 complete-record gaging stations; elevation and contents at 19 lakes and reservoirs; water-quality records at 2 precipitation stations, water-level data at 18 observation wells; and records of specific conductance, pH, water temperature, dissolved oxygen, and turbidity at 8 gaging stations. Also included are discharge data for 26 high-flow partial-record stations, and miscellaneous onsite water-quality data collected at 134 stations, and suspended-sediment concentration for 12 stations. These data represent that part of the National Water Information System collected by the U.S. Geological Survey in cooperation with local, State, and Federal agencies in Kansas.

Water Resources Data, Kansas, Water Year 1999

USGS Publications Warehouse

Putnam, J.E.; Lacock, D.L.; Schneider, D.R.; Carlson, M.D.

2000-01-01

Water-resources data for the 1999 water year for Kansas consist of records of stage, discharge, and water quality of streams; elevation and contents of lakes and reservoirs; and water levels of ground-water wells. This report contains records for water discharge at 143 gaging stations; elevation and contents at 19 watershed lakes and reservoirs; and water-level data at 19 observation wells; and records of specific conductance, pH, water temperature, dissolved oxygen, and turbidity at 4 stations. Also included are data for 26 high-flow and 2 low-flow partial-record stations; and 2 chemical quality of precipitation stations. Miscellaneous onsite water-quality data were collected at 132 stations. These data represent that part of the National Water Information System collected by the U.S. Geological Survey in cooperation with State, local, and Federal agencies in Kansas.

In-situ method to remove iron and other metals from solution in groundwater down gradient from permeable reactive barrier

DOEpatents

Carpenter, Clay E.; Morrison, Stanley J.

2001-07-03

This invention is directed to a process for treating the flow of anaerobic groundwater through an aquifer with a primary treatment media, preferably iron, and then passing the treated groundwater through a second porous media though which an oxygenated gas is passed in order to oxygenate the dissolved primary treatment material and convert it into an insoluble material thereby removing the dissolved primary treatment material from the groundwater.

The water quality of Sam Rayburn Reservoir, eastern Texas

USGS Publications Warehouse

Rawson, Jack; Lansford, Myra W.

1971-01-01

Results of periodic surveys indicate that dissolved-oxygen concentrations at three sites in the 19-mile reach of the Angelina River downstream from Sam Rayburn Dam were low in late summer and early fall after periods of summer stagnation in the reservoir. Moreover, the amount of reaeration that occurred in the reach was insignificant. During periods when the dissolved-oxygen deficiency was large, the concentrations of iron and manganese at each of the three sites increased greatly.

Dissolving Bubbles in Glass

NASA Technical Reports Server (NTRS)

Weinberg, M. C.; Oronato, P. I.; Uhlmann, D. R.

1984-01-01

Analytical expression used to calculate time it takes for stationary bubbles of oxygen and carbon dioxide to dissolve from glass melt. Technique based on analytical expression for bubble radius as function time, with consequences of surface tension included.

Prediction of dissolved oxygen in the Mediterranean Sea along Gaza, Palestine - an artificial neural network approach.

PubMed

Zaqoot, Hossam Adel; Ansari, Abdul Khalique; Unar, Mukhtiar Ali; Khan, Shaukat Hyat

2009-01-01

Artificial Neural Networks (ANNs) are flexible tools which are being used increasingly to predict and forecast water resources variables. The human activities in areas surrounding enclosed and semi-enclosed seas such as the Mediterranean Sea always produce in the long term a strong environmental impact in the form of coastal and marine degradation. The presence of dissolved oxygen is essential for the survival of most organisms in the water bodies. This paper is concerned with the use of ANNs - Multilayer Perceptron (MLP) and Radial Basis Function neural networks for predicting the next fortnight's dissolved oxygen concentrations in the Mediterranean Sea water along Gaza. MLP and Radial Basis Function (RBF) neural networks are trained and developed with reference to five important oceanographic variables including water temperature, wind velocity, turbidity, pH and conductivity. These variables are considered as inputs of the network. The data sets used in this study consist of four years and collected from nine locations along Gaza coast. The network performance has been tested with different data sets and the results show satisfactory performance. Prediction results prove that neural network approach has good adaptability and extensive applicability for modelling the dissolved oxygen in the Mediterranean Sea along Gaza. We hope that the established model will help in assisting the local authorities in developing plans and policies to reduce the pollution along Gaza coastal waters to acceptable levels.

Magnitudes, nature, and effects of point and nonpoint discharges in the Chattahoochee River basin, Atlanta to West Point Dam, Georgia

USGS Publications Warehouse

Stamer, J.K.; Cherry, R.N.; Faye, R.E.; Kleckner, R.L.

1978-01-01

On an average annual basis and during the storm period of March 12-15, 1976, nonpoint-source loads for most constituents were larger than point-source loads at the Whitesburg station, located on the Chattahoochee River about 40 miles downstream from Atlanta, GA. Most of the nonpoint-source constituent loads in the Atlanta to Whitesburg reach were from urban areas. Average annual point-source discharges accounted for about 50 percent of the dissolved nitrogen, total nitrogen, and total phosphorus loads and about 70 percent of the dissolved phosphorus loads at Whitesburg. During a low-flow period, June 1-2, 1977, five municipal point-sources contributed 63 percent of the ultimate biochemical oxygen demand, and 97 percent of the ammonium nitrogen loads at the Franklin station, at the upstream end of West Point Lake. Dissolved-oxygen concentrations of 4.1 to 5.0 milligrams per liter occurred in a 22-mile reach of the river downstream from Atlanta due about equally to nitrogenous and carbonaceous oxygen demands. The heat load from two thermoelectric powerplants caused a decrease in dissolved-oxygen concentration of about 0.2 milligrams per liter. Phytoplankton concentrations in West Point Lake, about 70 miles downstream from Atlanta, could exceed three million cells per millimeter during extended low-flow periods in the summer with present point-source phosphorus loads. (Woodard-USGS)

Impact of the temporal variation of oxygen contents in the water column on the biogeochemistry of the benthic zone

NASA Astrophysics Data System (ADS)

Rigaud, Sylvain; Deflandre, Bruno; Grenz, Christian; Pozzato, Lara; Cesbron, Florian; Meulé, Samuel; Bonin, Patricia; Michotey, Valérie; Mirleau, Pascal; Mirleau, Fatma; Knoery, Joel; Zuberer, Frédéric; Guillemain, Dorian; Marguerite, Sébatien; Mayot, Nicolas; Faure, Vincent; Grisel, Raphael; Radakovitch, Olivier

2017-04-01

The desoxygenation of the water column in coastal areas, refered as coastal hypoxia, is currently a growing phenomenon still particularly complex to predict. This is mainly due to the fact that the biogeochemical response of the benthic ecosystem to the variation of the oxygen contents in the water column remains poorly understood. Dissolved oxygen concentration is a key parameter controling the benthic micro- and macro-community as well as the biogeochemical reactions occuring in the surface sediment. More particularly, the variation over variable time scales (from hour to years) of the oxygen deficit may induce different pathways for biogeochemical processes such as the oxydation of freshly deposited organic matter and nutrients and metals recycling. This results in variable chemical fluxes at the sediment-water interface, that may in turn, support the eutrophication and desoxygenation of the aquatic system. Our study focus on the Berre lagoon, an eutrophicated mediterranean lagoon impacted by hypoxia events in the water column. Three stations, closely located but impacted by contrasted temporal variation of oxygen deficit in the water column were selected: one station with rare oxygen deficit and with functionnal macrofauna community, one station with almost permanent oxygen deficit and no macrofauna community and one intermediate station with seasonnal oxygen deficit and degraded macrofauna community. Each station was surveyed once during a same field survey while the intermediate station was surveyed seasonnaly. For each campaign, we report vertical profiles of the main chemical components (oxygen, nutrients, metals) along the water-column/sediment continuum, with an increased vertical resolution in the benthic zone using a multi-tool approach (high vertical resolution suprabenthic water sampler and microsensors profiler). In addition, total chemical fluxes at the sediment-water interface was obtained using benthic chambers. This dataset was used to evaluate the influence, of the oxygen concentrations (and its short and long-term variations) in the water column on the nature and location of the main biogeochemical reactions occuring in the benthic zone and the resulting fluxes at the sediment-water interface.

Fractions and biodegradability of dissolved organic matter derived from different composts.

PubMed

Wei, Zimin; Zhang, Xu; Wei, Yuquan; Wen, Xin; Shi, Jianhong; Wu, Junqiu; Zhao, Yue; Xi, Beidou

2014-06-01

An experiment was conducted to determine the fractions of molecular weights (MW) and the biodegradability of dissolved organic matter (DOM) in mature composts derived from dairy cattle manure (DCM), kitchen waste (KW), cabbage waste (CW), tomato stem waste (TSW), municipal solid waste (MSW), green waste (GW), chicken manure (CM), sludge (S), and mushroom culture waste (MCW). There were distinct differences in the concentration and MW fractions of DOM, and the two measures were correlated. Fraction MW>5kDa was the major component of DOM in all mature composts. Determined 5day biochemical oxygen demand (BOD5) of DOM was correlated to the concentration of DOM and all MW fractions except MW>5kDa, indicating that the biodegradability of DOM was a function of the content and proportion of fraction MW<5kDa. This study suggests that the amount and distribution of low MW fractions affect DOM biodegradability. Copyright © 2014 Elsevier Ltd. All rights reserved.

Effects of ultrasound pre-treatment on the amount of dissolved organic matter extracted from food waste.

PubMed

Jiang, Jianguo; Gong, Changxiu; Wang, Jiaming; Tian, Sicong; Zhang, Yujing

2014-03-01

This paper describes a series of studies on the effects of food waste disintegration using an ultrasonic generator and the production of volatile fatty acids (VFAs) by anaerobic hydrolysis. The results suggest that ultrasound treatment can significantly increase COD [chemical oxygen demand], proteins and reducing sugars, but decrease that of lipids in food waste supernatant. Ultrasound pre-treatment boosted the production of VFAs dramatically during the fermentation of food waste. At an ultrasonic energy density of 480W/L, we treated two kinds of food waste (total solids (TS): 40 and 100g/L, respectively) with ultrasound for 15min. The amount of COD dissolved from the waste increased by 1.6-1.7-fold, proteins increased by 3.8-4.3-fold, and reducing sugars increased by 4.4-3.6-fold, whereas the lipid content decreased from 2 to 0.1g/L. Additionally, a higher VFA yield was observed following ultrasonic pre-treatment. Copyright © 2013 Elsevier Ltd. All rights reserved.

Nitrous oxide emissions and dissolved oxygen profiling in a full-scale nitrifying activated sludge treatment plant.

PubMed

Aboobakar, Amina; Cartmell, Elise; Stephenson, Tom; Jones, Mark; Vale, Peter; Dotro, Gabriela

2013-02-01

This paper reports findings from online, continuous monitoring of dissolved and gaseous nitrous oxide (N₂O), combined with dissolved oxygen (DO) and ammonia loading, in a full-scale nitrifying activated sludge plant. The study was conducted over eight weeks, at a 210,000 population equivalent sewage treatment works in the UK. Results showed diurnal variability in the gaseous and dissolved N₂O emissions, with hourly averages ranging from 0 to 0.00009 kgN₂O-N/h for dissolved and 0.00077-0.0027 kgN₂O-N/h for gaseous nitrous oxide emissions respectively, per ammonia loading, depending on the time of day. Similarly, the spatial variability was high, with the highest emissions recorded immediately after the anoxic zone and in the final pass of the aeration lane, where ammonia concentrations were typically below 0.5 mg/L. Emissions were shown to be negatively correlated to dissolved oxygen, which fluctuated between 0.5 and 2.5 mgO₂/L, at the control set point of 1.5 mgO₂/L. The resulting dynamic DO conditions are known to favour N₂O production, both by autotrophic and heterotrophic processes in mixed cultures. Average mass emissions from the lane were greater in the gaseous (0.036% of the influent total nitrogen) than in the dissolved (0.01% of the influent total nitrogen) phase, and followed the same diurnal and spatial patterns. Nitrous oxide emissions corresponded to over 34,000 carbon dioxide equivalents/year, adding 13% to the carbon footprint associated with the energy requirements of the monitored lane. A clearer understanding of emissions obtained from real-time data can help towards finding the right balance between improving operational efficiency and saving energy, without increasing N₂O emissions. Copyright © 2012 Elsevier Ltd. All rights reserved.

Corrosion behavior of oxide dispersion strengthened ferritic steels in supercritical water

NASA Astrophysics Data System (ADS)

Gao, Wenhua; Guo, Xianglong; Shen, Zhao; Zhang, Lefu

2017-04-01

The corrosion resistance of three different Cr content oxide dispersion strengthened (ODS) ferritic steels in supercritical water (SCW) and their passive films formed on the surface have been investigated. The results show that the dissolved oxygen (DO) and chemical composition have significant influence on the corrosion behavior of the ODS ferritic steels. In 2000 ppb DO SCW at 650 °C, the 14Cr-4Al ODS steel forms a tri-layer oxide film and the surface morphologies have experienced four structures. For the tri-layer oxide film, the middle layer is mainly Fe-Cr spinel and the Al is gradually enriched in the inner layer.

Process for desulfurizing petroleum feedstocks

DOEpatents

Gordon, John Howard; Alvare, Javier

2014-06-10

A process for upgrading an oil feedstock includes reacting the oil feedstock with a quantity of an alkali metal, wherein the reaction produces solid materials and liquid materials. The solid materials are separated from the liquid materials. The solid materials may be washed and heat treated by heating the materials to a temperature above 400.degree. C. The heat treating occurs in an atmosphere that has low oxygen and water content. Once heat treated, the solid materials are added to a solution comprising a polar solvent, where sulfide, hydrogen sulfide or polysulfide anions dissolve. The solution comprising polar solvent is then added to an electrolytic cell, which during operation, produces alkali metal and sulfur.

Vertical and temporal dynamics of cyanobacteria in the Carpina potable water reservoir in northeastern Brazil.

PubMed

Moura, A N; Dantas, E W; Oliveira, H S B; Bittencourt-Oliveira, M C

2011-05-01

This study analysed vertical and temporal variations of cyanobacteria in a potable water supply in northeastern Brazil. Samples were collected from four reservoir depths in the four months; September and December 2007; and March and June 2008. The water samples for the determination of nutrients and cyanobacteria were collected using a horizontal van Dorn bottle. The samples were preserved in 4% formaldehyde for taxonomic analysis using an optical microscope, and water aliquots were preserved in acetic Lugol solution for determination of density using an inverted microscope. High water temperatures, alkaline pH, low transparency, high phosphorous content and limited nitrogen content were found throughout the study. Dissolved oxygen stratification occurred throughout the study period whereas temperature stratification occurred in all sampling months, with the exception of June. No significant vertical differences were recorded for turbidity or total and dissolved forms of nutrients. There were high levels of biomass arising from Planktothrix agardhii, Cylindrospermopsis raciborskii, Geitlerinema amphibium and Pseudanabaena catenata. The study demonstrates that, in a tropical eutrophic environment with high temperatures throughout the water column, perennial multi-species cyanobacterial blooms, formed by species capable of regulating their position in the water column (those that have gas vesicles for buoyancy), are dominant in the photic and aphotic strata.

Combined Effects of Dissolved Nutrients and Oxygen on Plant Litter Decomposition and Associated Fungal Communities.

PubMed

Gomes, Patrícia Pereira; Ferreira, Verónica; Tonin, Alan M; Medeiros, Adriana Oliveira; Júnior, José Francisco Gonçalves

2018-05-01

Aquatic ecosystems worldwide have been substantially altered by human activities, which often induce changes in multiple factors that can interact to produce complex effects. Here, we evaluated the combined effects of dissolved nutrients (nitrogen [N] and phosphorus [P]; three levels: concentration found in oligotrophic streams in the Cerrado biome, 10× and 100× enriched) and oxygen (O 2 ; three levels: hypoxic [4% O 2 ], depleted [55% O 2 ], and saturated [96% O 2 ]) on plant litter decomposition and associated fungal decomposers in laboratory microcosms simulating stream conditions under distinct scenarios of water quality deterioration. Senescent leaves of Maprounea guianensis were incubated for 10 days in an oligotrophic Cerrado stream to allow microbial colonization and subsequently incubated in microcosms for 21 days. Leaves lost 1.1-3.0% of their initial mass after 21 days, and this was not affected either by nutrients or oxygen levels. When considering simultaneous changes in nutrients and oxygen concentrations, simulating increased human pressure, fungal biomass accumulation, and sporulation rates were generally inhibited. Aquatic hyphomycete community structure was also affected by changes in nutrients and oxygen availability, with stronger effects found in hypoxic treatments than in depleted or saturated oxygen treatments. This study showed that the effects of simultaneous changes in the availability of dissolved nutrients and oxygen in aquatic environments can influence the activity and composition of fungal communities, although these effects were not translated into changes in litter decomposition rates.

Understanding why the volume of suboxic waters does not increase over centuries of global warming in an Earth System Model

NASA Astrophysics Data System (ADS)

Gnanadesikan, A.; Dunne, J. P.; John, J.

2012-03-01

Global warming is expected to reduce oxygen solubility and vertical exchange in the ocean, changes which would be expected to result in an increase in the volume of hypoxic waters. A simulation made with a full Earth System model with dynamical atmosphere, ocean, sea ice and biogeochemical cycling (the Geophysical Fluid Dynamics Laboratory's Earth System Model 2.1) shows that this holds true if the condition for hypoxia is set relatively high. However, the volume of the most hypoxic (i.e., suboxic) waters does not increase under global warming, as these waters actually become more oxygenated. We show that the rise in dissolved oxygen in the tropical Pacific is associated with a drop in ventilation time. A term-by-term analysis within the least oxygenated waters shows an increased supply of dissolved oxygen due to lateral diffusion compensating an increase in remineralization within these highly hypoxic waters. This lateral diffusive flux is the result of an increase of ventilation along the Chilean coast, as a drying of the region under global warming opens up a region of wintertime convection in our model. The results highlight the potential sensitivity of suboxic waters to changes in subtropical ventilation as well as the importance of constraining lateral eddy transport of dissolved oxygen in such waters.

Water quality of Tampa Bay, Florida, June 1972-May 1976

USGS Publications Warehouse

Goetz, Carole L.; Goodwin, Carl R.

1980-01-01

A comprehensive assessment of the water quality of Tampa Bay, Florida, was initiated in 1970 to provide background information to evaluate the effects of widening and deepening the ship channel to the port of Tampa. This report provides results of water-quality sampling in the bay from 1972 to 1976, prior to dredging. Measurements of temperature, dissolved oxygen, pH, turbidity, specific conductance, biochemical oxygen demand, and total organic carbon were made as well as measurements for several nutrient, metal, and pesticide parameters. Many parameters were measured at as many as three points in the vertical. These data indicate that Tampa Bay is well-mixed vertically with little density stratification. Time histories of average temperature, dissolved oxygen, pH, turbidity, specific conductance and nutrient values within four subareas of Tampa Bay are given to reveal seasonal or other trends during the period of record. Temperature, dissolved oxygen, pH, turbidity, specific conductance, nutrient, biochemical oxygen demand, total organic carbon, and metal data are also presented as areal distributions. Nutrient concentrations were generally higher in Hillsborough Bay than in other sub-areas of Tampa Bay. Biochemical oxygen demand, total organic carbon, and total organic nitrogen distribution patterns show regions of highest concentrations to be along bay shorelines near population centers. Of the metals analyzed, all were present in concentrations of less than 1 milligram per liter. (USGS)

Measures of net oxidant concentration in seawater

NASA Astrophysics Data System (ADS)

Jackson, George A.; Williams, Peter M.

1988-02-01

Dissolved oxygen deficits in the ocean have been used as a measure of the organic matter oxidized in a volume of water. Such organic matter is usually assumed to be predominantly settled particles. Using dissolved oxygen concentration in this way has two problems: first, it does not differentiate between oxidant consumed by the pool of dissolved organic matter present near the ocean surface and oxidant consumed by organic matter contained by falling particles; second, it does not account for other oxidant sources, such as nitrate, which can be as important to organic matter decay as oxygen in low-oxygen water, such as off Peru or in the Southern California submarine basins. New parameters provide better measures of the net oxidant concentration in a water parcel. One such, NetOx, is changed only by gaseous exchange with the atmosphere, exchange with the benthos, or the production or consumption of sinking particles. A simplified version of NetOx, NetOx = [O2] + 1.25[NO3-] - [TOC], where TOC (total organic carbon), the dissolved organic carbon (DOC) plus the suspended particulate organic carbon (POC), provides an index based on the usually dominant variables. Calculation of NetOx and a second property, NetOC ([O2] - [TOC]), for data from GEOSECS and ourselves in the Atlantic and Pacific oceans using property-property graphs show differences from those from oxygen deficits alone. Comparison of NetOx and NetOC concentrations at high and low latitudes of the Pacific Ocean shows the difference in surface water oxidant concentrations is even larger than the difference in oxygen concentration. Vertical particle fluxes off Peru calculated from NetOx gradients are much greater than those calculated from oxygen gradients. The potential value of NetOx and NetOC as parameters to understand particle fluxes implies that determination of TOC should be a routine part of hydrographic measurements.

Geochemical and hydrologic controls on phosphorus transport in a sewage-contaminated sand and gravel aquifer near Ashumet Pond, Cape Cod, Massachusetts

USGS Publications Warehouse

Walter, D.A.; Rea, B.A.; Stollenwerk, K.G.; Savoie, Jennifer G.

1995-01-01

The disposal of secondarily treated sewage onto rapid infiltration sand beds at the Massachusetts Military Reservation, Cape Cod, Massachusetts, has created a sewage plume in the underlying sand and gravel aquifer; the part of the\\x11sewage plume that contains dissolved phosphorus extends about 2,500 feet downgradient of the sewage-disposal beds. A part of the plume that\\x11contains nearly 2 milligrams per liter of phosphorus currently (1993) discharges into Ashumet Pond along about 700 feet of shoreline. The sewage plume discharges from about 59 to about 76 kilograms of phosphorus per year into the pond. Hydraulic-head measurements indicate that the north end of Ashumet Pond is a ground-water sink and an increased component of ground-water discharge and phosphorus flux into\\x11the pond occurs at higher water levels. Phosphorus was mobile in ground water in two distinct geochemical environments-an anoxic zone that contains no dissolved oxygen and as much as 25\\x11milligrams per liter of dissolved iron, and a more areally extensive suboxic zone that contains little or no iron, low but detectable dissolved oxygen, and as much as 12 milligrams per liter of dissolved manganese. Dissolved phosphorus is mobile in the suboxic geochemical environment because continued phosphorus loading has filled available sorption sites in the aquifer. Continued disposal of sewage since 1936 has created a large reservoir of sorbed phosphorus that is much greater than the mass of dissolved phosphorus in the ground water; the average ratio of sorbed to dissolved phosphorus in the anoxic and suboxic parts of the sewage plume were 31:1 and 155:1, respectively. Column experiments indicate that phosphorus in the anoxic core of the plume containing dissolved iron may be immobilized within 17 years by sorption and coprecipitation with new iron oxyhydroxides following the cessation of sewage disposal and the introduction of uncontaminated oxygenated ground water into the aquifer in December 1995. Residual oxygen demand associated with sorbed organic compounds and ammonia could retard the movement of oxygenated water into the aquifer. Sorbed phosphorus in the suboxic zone of the aquifer will continue to desorb into the ground water and will remain mobile in the ground water for perhaps hundreds of years. Also, the introduction of uncontaminated water into the aquifer may cause dissolved-phosphorus concentrations in the suboxic zone of the aquifer to increase sharply and remain higher than precessation levels for many years due to the desorption of loosely bound phosphorus. Data from three sampling sites, located along the eastern and western boundaries of the sewage plume and downgradient of abandoned sewage-disposal beds, indicate that ground-water mixing and phosphorus desorption may already be occurring in the aquifer in response to the introduction of uncontaminated recharge water into previously contaminated parts of the aquifer.

Sediment oxygen demand in the Saddle River and Salem River watersheds, New Jersey, July-August 2008

USGS Publications Warehouse

Heckathorn, Heather A.; Gibs, Jacob

2010-01-01

Many factors, such as river depth and velocity, biochemical oxygen demand, and algal productivity, as well as sediment oxygen demand, can affect the concentration of dissolved oxygen in the water column. Measurements of sediment oxygen demand, in conjunction with those of other water-column water-quality constituents, are useful for quantifying the mechanisms that affect in-stream dissolved-oxygen concentrations. Sediment-oxygen-demand rates are also needed to develop and calibrate a water-quality model being developed for the Saddle River and Salem River Basins in New Jersey to predict dissolved-oxygen concentrations. This report documents the methods used to measure sediment oxygen demand in the Saddle River and Salem River watersheds along with the rates of sediment oxygen demand that were obtained during this investigation. In July and August 2008, sediment oxygen demand was measured in situ in the Saddle River and Salem River watersheds. In the Saddle River Basin, sediment oxygen demand was measured twice at two sites and once at a third location; in the Salem River Basin, sediment oxygen demand was measured three times at two sites and once at a third location. In situ measurements of sediment oxygen demand in the Saddle River and Salem River watersheds ranged from 0.8 to 1.4 g/m2d (grams per square meter per day) and from 0.6 to 7.1 g/m2d at 20 degrees Celsius, respectively. Except at one site in this study, rates of sediment oxygen demand generally were low. The highest rate of sediment oxygen demand measured during this investigation, 7.1 g/m2d, which occurred at Courses Landing in the Salem River Basin, may be attributable to the consumption of oxygen by a large amount of organic matter (54 grams per kilogram as organic carbon) in the streambed sediments or to potential error during data collection. In general, sediment oxygen demand increased with the concentration of organic carbon in the streambed sediments. Repeated measurements made 6 to 7 days apart at the same site locations resulted in similar values.

In vitro genotoxicity of asbestos substitutes induced by coupled stimulation of dissolved high-valence ions and oxide radicals.

PubMed

Huo, Tingting; Dong, Faqin; Deng, Jianjun; Zhang, Qingbi; Ye, Wei; Zhang, Wei; Wang, Pingping; Sun, Dongping

2017-08-01

The wide use of asbestos and its substitutes has given rise to studies on their possible harmful effects on human health and environment. However, their toxic effects remain unclear. The present study was aimed to disclose the coupled effects of dissolved high-valence ions and oxide radicals using the in vitro cytotoxicity and genotoxicity of chrysotile (CA), nano-SiO 2 (NS), ceramic fiber (CF), glass fiber (GF), and rock wool (RW) on Chinese hamster lung cells V79. All samples induced cell mortality correlated well with the chemical SiO 2 content of asbestos substitutes and the amount of dissolved Si. Alkali or alkaline earth metal elements relieved mortality of V79 cells; Al 2 O 3 reinforced toxicity of materials. Asbestos substitutes generated lasting, increasing amount of acellular ·OH which formed at the fiber surface at sites with loose/unsaturated bonds, as well as by catalytic reaction through dissolved iron. Accumulated mechanical and radical stimulation induced the intracellular reactive oxygen species (ROS) elevation, morphology change, and deviating trans-membrane ion flux. The cellular ROS appeared as NS > GF > CF ≈ CA > RW, consistent with cell mortality rather than with acellular ·OH generation. Chromosomal and DNA lesions in V79 cells were not directly associated with the cellular ROS, while influenced by dissolved high-valence irons in the co-culture medium. In conclusion, ions from short-time dissolution of dust samples and the generation of extracellular ·OH presented combined effects in the elevation of intracellular ROS, which further synergistically induced cytotoxicity and genotoxicity.

Influence of oxidation state on water solubility of Si nanoparticles prepared by laser ablation in water

NASA Astrophysics Data System (ADS)

Ryabchikov, Yu. V.; Al-Kattan, A.; Chirvony, V.; Sanchez-Royo, J. F.; Sentis, M.; Timoshenko, V. Yu.; Kabashin, A. V.

2017-02-01

Femtosecond laser fragmentation from preliminarily prepared water-dispersed Si microcolloids was used to synthesize bare (ligand-free) spherical silicon nanoparticles (Si-NPs) with low size dispersion and controllable mean size from a few nm to several tens of nm. In order to control the oxidation state of Si-NPs, the fragmentation was performed in normal oxygen-saturated water (oxygen-rich conditions) or in water disoxygenated by pumping with noble gases (Ag, He) before and during the experiment (oxygen-free conditions). XPS and TEM studies revealed that Si-NPs were composed of Si nanocrystals with inclusions of silicon oxide species, covered by SiOx (1 < x < 2) shell, while the total oxide content depended whether Si-NPs were prepared in oxygen-rich or oxygen-free conditions. When placed into a dialysis box, waterdispersed Si-NPs rapidly dissolved, which was evidenced by TEM data. In this case, NPs prepared under oxygen-rich conditions demonstrated much faster dissolution kinetics and their complete disappearance after 7-10 days, while the dissolution process of less oxidized counterparts could last much longer (25-30 days). Much fast dissolution kinetics of more oxidized Si-NPs was attributed to more friable structure of nanoparticle core due to the presence of numerous oxidation-induced defects. Laser-synthesized Si-NPs are of paramount importance for biomedical applications.

Effects of reduced dissolved oxygen concentrations on physiology and fluorescence of hermatypic corals and benthic algae

PubMed Central

Smith, Jennifer E.; Thompson, Melissa

2014-01-01

While shifts from coral to seaweed dominance have become increasingly common on coral reefs and factors triggering these shifts successively identified, the primary mechanisms involved in coral-algae interactions remain unclear. Amongst various potential mechanisms, algal exudates can mediate increases in microbial activity, leading to localized hypoxic conditions which may cause coral mortality in the direct vicinity. Most of the processes likely causing such algal exudate induced coral mortality have been quantified (e.g., labile organic matter release, increased microbial metabolism, decreased dissolved oxygen availability), yet little is known about how reduced dissolved oxygen concentrations affect competitive dynamics between seaweeds and corals. The goals of this study were to investigate the effects of different levels of oxygen including hypoxic conditions on a common hermatypic coral Acropora yongei and the common green alga Bryopsis pennata. Specifically, we examined how photosynthetic oxygen production, dark and daylight adapted quantum yield, intensity and anatomical distribution of the coral innate fluorescence, and visual estimates of health varied with differing background oxygen conditions. Our results showed that the algae were significantly more tolerant to extremely low oxygen concentrations (2–4 mg L−1) than corals. Furthermore corals could tolerate reduced oxygen concentrations, but only until a given threshold determined by a combination of exposure time and concentration. Exceeding this threshold led to rapid loss of coral tissue and mortality. This study concludes that hypoxia may indeed play a significant role, or in some cases may even be the main cause, for coral tissue loss during coral-algae interaction processes. PMID:24482757

Effects of reduced dissolved oxygen concentrations on physiology and fluorescence of hermatypic corals and benthic algae.

PubMed

Haas, Andreas F; Smith, Jennifer E; Thompson, Melissa; Deheyn, Dimitri D

2014-01-01

While shifts from coral to seaweed dominance have become increasingly common on coral reefs and factors triggering these shifts successively identified, the primary mechanisms involved in coral-algae interactions remain unclear. Amongst various potential mechanisms, algal exudates can mediate increases in microbial activity, leading to localized hypoxic conditions which may cause coral mortality in the direct vicinity. Most of the processes likely causing such algal exudate induced coral mortality have been quantified (e.g., labile organic matter release, increased microbial metabolism, decreased dissolved oxygen availability), yet little is known about how reduced dissolved oxygen concentrations affect competitive dynamics between seaweeds and corals. The goals of this study were to investigate the effects of different levels of oxygen including hypoxic conditions on a common hermatypic coral Acropora yongei and the common green alga Bryopsis pennata. Specifically, we examined how photosynthetic oxygen production, dark and daylight adapted quantum yield, intensity and anatomical distribution of the coral innate fluorescence, and visual estimates of health varied with differing background oxygen conditions. Our results showed that the algae were significantly more tolerant to extremely low oxygen concentrations (2-4 mg L(-1)) than corals. Furthermore corals could tolerate reduced oxygen concentrations, but only until a given threshold determined by a combination of exposure time and concentration. Exceeding this threshold led to rapid loss of coral tissue and mortality. This study concludes that hypoxia may indeed play a significant role, or in some cases may even be the main cause, for coral tissue loss during coral-algae interaction processes.

Simulation of annual biogeochemical cycles of nutrient balance, phytoplankton bloom(s), and DO in Puget Sound using an unstructured grid model

DOE Office of Scientific and Technical Information (OSTI.GOV)

Khangaonkar, Tarang; Sackmann, Brandon; Long, Wen

2012-08-14

Nutrient pollution from rivers, nonpoint source runoff, and nearly 100 wastewater discharges is a potential threat to the ecological health of Puget Sound with evidence of hypoxia in some basins. However, the relative contributions of loads entering Puget Sound from natural and anthropogenic sources, and the effects of exchange flow from the Pacific Ocean are not well understood. Development of a quantitative model of Puget Sound is thus presented to help improve our understanding of the annual biogeochemical cycles in this system using the unstructured grid Finite-Volume Coastal Ocean Model framework and the Integrated Compartment Model (CE-QUAL-ICM) water quality kinetics.more » Results based on 2006 data show that phytoplankton growth and die-off, succession between two species of algae, nutrient dynamics, and dissolved oxygen in Puget Sound are strongly tied to seasonal variation of temperature, solar radiation, and the annual exchange and flushing induced by upwelled Pacific Ocean waters. Concentrations in the mixed outflow surface layer occupying approximately 5–20 m of the upper water column show strong effects of eutrophication from natural and anthropogenic sources, spring and summer algae blooms, accompanied by depleted nutrients but high dissolved oxygen levels. The bottom layer reflects dissolved oxygen and nutrient concentrations of upwelled Pacific Ocean water modulated by mixing with biologically active surface outflow in the Strait of Juan de Fuca prior to entering Puget Sound over the Admiralty Inlet. The effect of reflux mixing at the Admiralty Inlet sill resulting in lower nutrient and higher dissolved oxygen levels in bottom waters of Puget Sound than the incoming upwelled Pacific Ocean water is reproduced. Finally, by late winter, with the reduction in algal activity, water column constituents of interest, were renewed and the system appeared to reset with cooler temperature, higher nutrient, and higher dissolved oxygen waters from the Pacific Ocean.« less

Model-Based Feasibility Assessment of Membrane Biofilm Reactor to Achieve Simultaneous Ammonium, Dissolved Methane, and Sulfide Removal from Anaerobic Digestion Liquor

PubMed Central

Chen, Xueming; Liu, Yiwen; Peng, Lai; Yuan, Zhiguo; Ni, Bing-Jie

2016-01-01

In this study, the membrane biofilm reactor (MBfR) is proposed to achieve simultaneous removal of ammonium, dissolved methane, and sulfide from main-stream and side-stream anaerobic digestion liquors. To avoid dissolved methane stripping, oxygen is introduced through gas-permeable membranes, which also from the substratum for the growth of a biofilm likely comprising ammonium oxidizing bacteria (AOB), anaerobic ammonium oxidation (Anammox) bacteria, denitrifying anaerobic methane oxidation (DAMO) microorganisms, aerobic methane oxidizing bacteria (MOB), and sulfur oxidizing bacteria (SOB). A mathematical model is developed and applied to assess the feasibility of such a system and the associated microbial community structure under different operational conditions. The simulation studies demonstrate the feasibility of achieving high-level (>97.0%), simultaneous removal of ammonium, dissolved methane, and sulfide in the MBfRs from both main-stream and side-stream anaerobic digestion liquors through adjusting the influent surface loading (or hydraulic retention time (HRT)) and the oxygen surface loading. The optimal HRT was found to be inversely proportional to the corresponding oxygen surface loading. Under the optimal operational conditions, AOB, DAMO bacteria, MOB, and SOB dominate the biofilm of the main-stream MBfR, while AOB, Anammox bacteria, DAMO bacteria, and SOB coexist in the side-stream MBfR to remove ammonium, dissolved methane, and sulfide simultaneously. PMID:27112502

Marine methane paradox explained by bacterial degradation of dissolved organic matter

NASA Astrophysics Data System (ADS)

Repeta, Daniel J.; Ferrón, Sara; Sosa, Oscar A.; Johnson, Carl G.; Repeta, Lucas D.; Acker, Marianne; Delong, Edward F.; Karl, David M.

2016-12-01

Biogenic methane is widely thought to be a product of archaeal methanogenesis, an anaerobic process that is inhibited or outcompeted by the presence of oxygen and sulfate. Yet a large fraction of marine methane delivered to the atmosphere is produced in high-sulfate, fully oxygenated surface waters that have methane concentrations above atmospheric equilibrium values, an unexplained phenomenon referred to as the marine methane paradox. Here we use nuclear magnetic resonance spectroscopy to show that polysaccharide esters of three phosphonic acids are important constituents of dissolved organic matter in seawater from the North Pacific. In seawater and pure culture incubations, bacterial degradation of these dissolved organic matter phosphonates in the presence of oxygen releases methane, ethylene and propylene gas. Moreover, we found that in mutants of a methane-producing marine bacterium, Pseudomonas stutzeri, disrupted in the C-P lyase phosphonate degradation pathway, methanogenesis was also disabled, indicating that the C-P lyase pathway can catalyse methane production from marine dissolved organic matter. Finally, the carbon stable isotope ratio of methane emitted during our incubations agrees well with anomalous isotopic characteristics of seawater methane. We estimate that daily cycling of only about 0.25% of the organic matter phosphonate inventory would support the entire atmospheric methane flux at our study site. We conclude that aerobic bacterial degradation of phosphonate esters in dissolved organic matter may explain the marine methane paradox.

Statistical Exposé of a Multiple-Compartment Anaerobic Reactor Treating Domestic Wastewater.

PubMed

Pfluger, Andrew R; Hahn, Martha J; Hering, Amanda S; Munakata-Marr, Junko; Figueroa, Linda

2018-06-01

  Mainstream anaerobic treatment of domestic wastewater is a promising energy-generating treatment strategy; however, such reactors operated in colder regions are not well characterized. Performance data from a pilot-scale, multiple-compartment anaerobic reactor taken over 786 days were subjected to comprehensive statistical analyses. Results suggest that chemical oxygen demand (COD) was a poor proxy for organics in anaerobic systems as oxygen demand from dissolved inorganic material, dissolved methane, and colloidal material influence dissolved and particulate COD measurements. Additionally, univariate and functional boxplots were useful in visualizing variability in contaminant concentrations and identifying statistical outliers. Further, significantly different dissolved organic removal and methane production was observed between operational years, suggesting that anaerobic reactor systems may not achieve steady-state performance within one year. Last, modeling multiple-compartment reactor systems will require data collected over at least two years to capture seasonal variations of the major anaerobic microbial functions occurring within each reactor compartment.

Water quality in the tidal Potomac River and Estuary, hydrologic data report, 1979 water year

USGS Publications Warehouse

Blanchard, Stephen F.; Hahl, D.C.

1981-01-01

This report contains data on the physical and chemical properties measured during the 1979 water year for the tidal Potomac River and estuary. Data were collected routinely at five major stations and periodically at 14 intervening stations. Each major station represents a cross section through which the transport of selected dissolved and suspended materials will be computed. The intervening stations represent locations at which data were collected for special studies such as: salt water migration, dissolved oxygen dynamics, and other synoptic studies. About 960 samples were analyzed for silicate, Kjeldhal nitrogen, nitrite, phosphorus, chlorophyll and suspended sediment, with additional samples analyzed for organic carbon, calcium, magnesium, sodium, bicarbonate, sulfate, potassium, chloride, fluoride, seston and dissolved solids residue. In addition, about 1400 in-situ measurements of dissolved oxygen, specific conductance, temperature, and Secchi disk transparency are reported. (USGS)

BIODEGRADATION OF AROMATIC COMPOUNDS UNDER MIXED OXYGEN/DENITRIFYING CONDITIONS: A REVIEW

EPA Science Inventory

Bioremediation of aromatic hydrocarbons in groundwater and sediments is often limited by dissolved oxygen. Many aromatic hydrocarbons degrade very slowly or not at all under anaerobic conditions. Nitrate is a good alternative electron acceptor to oxygen, and denitrifying bacteria...

Determining Oxygen Isotopic Fractionation between the ferrous sulfate, melanterite, and aqueous sulfate

NASA Astrophysics Data System (ADS)

Shulaker, D. Z.; Kohl, I.; Coleman, M. L.

2011-12-01

Studying regions on Earth that are analogous to Mars serve as case studies for studying astrobiology and planetary surface rock formation processes. Rio Tinto, Spain is very rich in iron sulfates, and has an environment that is possibly very similar to the former environment on Mars. Certain bacteria play significant roles in accelerating pyrite oxidation rates, the products of which contribute to the formation of ferrous sulfates, such as melanterite. During mineral crystallization in an aqueous solution, there are systematic isotopic differences between dissolved species and solid phases. Quantifying this fractionation enables isotopic analysis to be used to trace the original isotopic signature of the dissolved species. Isotope fractionation has been determined for minerals such as gypsum and epsomite, and from these results and theoretical predictions, it is expected that melanterite, a mineral potentially found on Mars, would be more enriched in oxygen-18 relative to the aqueous solution from which it crystallized.Thus, determining the oxygen-18 isotopic fractionation between melanterite and dissolved sulfate has many potential benefits for understanding surface processes on Mars and its past environment. To investigate the oxygen isotope fractionation for melanterite, acidic aqueous solutions saturated with dissolved hydrated ferrous sulfate were evaporated at 25 deg C and 40 deg C and under different conditions to induce different evaporation rates. During evaporation, the aqueous solution and crystallized melanterite were sampled at different stages. Oxygen-18 isotopic compositions were then measured. However, the fractionations observed in the experiments were opposite from predictions. At 25 deg C without enhanced evaporation, the dissolved sulfate was +5.5 per mil relative to the solid, while at 40 deg C it was +4.3 per mil. With enhanced evaporation, fractionation was +2.1 per mil, while at 40 deg C it was +3.6 per mil. In addition, at 40 deg C, evaporation rates and fractionation were larger than at 25 deg C. Because no Rayleigh fractionation was observed, this system was not in equilibrium, and was most likely dominated by kinetics. Because of the unexpected results, further research will be conducted on the oxygen isotope fractionation of melanterite.

Effect of cation structure on the oxygen solubility and diffusivity in a range of bis{(trifluoromethyl)sulfonyl}imide anion based ionic liquids for lithium-air battery electrolytes.

PubMed

Neale, Alex R; Li, Peilin; Jacquemin, Johan; Goodrich, Peter; Ball, Sarah C; Compton, Richard G; Hardacre, Christopher

2016-04-28

This paper reports on the solubility and diffusivity of dissolved oxygen in a series of ionic liquids (ILs) based on the bis{(trifluoromethyl)sulfonyl}imide anion with a range of related alkyl and ether functionalised cyclic alkylammonium cations. Cyclic voltammetry has been used to observe the reduction of oxygen in ILs at a microdisk electrode and chronoamperometric measurements have then been applied to simultaneously determine both the concentration and the diffusion coefficient of oxygen in different ILs. The viscosity of the ILs and the calculated molar volume and free volume are also reported. It is found that, within this class of ILs, the oxygen diffusivity generally increases with decreasing viscosity of the neat IL. An inverse relationship between oxygen solubility and IL free volume is reported for the two IL families implying that oxygen is not simply occupying the available empty space. In addition, it is reported that the introduction of an ether-group into the IL cation structure promotes the diffusivity of dissolved oxygen but reduces the solubility of the gas.

Effect of phytoremediation on concentrations of benzene, toluene, naphthalene, and dissolved oxygen in groundwater at a former manufactured gas plant site, Charleston, South Carolina, USA, 1998–2014

USGS Publications Warehouse

Landmeyer, James E.; Effinger, Thomas N.

2016-01-01

Concentrations of benzene, toluene, naphthalene, and dissolved oxygen in groundwater at a former manufactured gas plant site near Charleston, South Carolina, USA, have been monitored since the installation of a phytoremediation system of hybrid poplar trees in 1998. Between 2000 and 2014, the concentrations of benzene, toluene, and naphthalene (BT&N) in groundwater in the planted area have decreased. For example, in the monitoring well containing the highest concentrations of BT&N, benzene concentrations decreased from 10,200 µg/L to less than 4000 µg/L, toluene concentrations decreased from 2420 µg/L to less than 20 µg/L, and naphthalene concentrations decreased from 6840 µg/L to less than 3000 µg/L. Concentrations of BT&N in groundwater in all wells were observed to be lower during the summer months relative to the winter months of a particular year during the first few years after installing the phytoremediation system, most likely due to increased transpiration and contaminant uptake by the hybrid poplar trees during the warm summer months; this pathway of uptake by trees was confirmed by the detection of benzene, toluene, and naphthalene in trees during sampling events in 2002, and later in the study in 2012. These data suggest that the phytoremediation system affects the groundwater contaminants on a seasonal basis and, over multiple years, has resulted in a cumulative decrease in dissolved-phase contaminant concentrations in groundwater. The removal of dissolved organic contaminants from the aquifer has resulted in a lower demand on dissolved oxygen supplied by recharge and, as a result, the redox status of the groundwater has changed from anoxic to oxic conditions. This study provides much needed information for water managers and other scientists on the viability of the long-term effectiveness of phytoremediation in decreasing groundwater contaminants and increasing dissolved oxygen at sites contaminated by benzene, toluene, and naphthalene.

Oxygen fugacity and piston cylinder capsule assemblies

NASA Astrophysics Data System (ADS)

Jakobsson, S.

2011-12-01

A double capsule assembly designed to control oxygen fugacity in piston cylinder experiments has been tested at 1200 °C and 10 kbar. The assembly consists of an outer Pt-capsule containing a solid buffer (Ni-NiO or Co-CoO plus H2O) and an inner AuPd-capsule containing the sample, H2O and a Pt-wire. To prevent direct contact with the buffer phases the AuPd-capsule is embedded in finely ground Al2O3 along with some coarser, fractured Al2O3 facilitating fluid inclusion formation. No water loss is observed in the sample even after 48 hrs but a slight increase in water content is observed in longer duration runs due to oxygen and hydrogen diffusion into the AuPd-capsule. Carbon from the furnace also diffuses through the outer Pt-capsule but reacts with H2O in the outer capsule to form CO2 and never reaches the inner capsule. Oxygen fugacity of runs in equilibrium with the Ni-NiO and Co-CoO buffers was measured by analyzing the Fe content of the Pt-wire in the sample1 and by analyzing Fe dissolved in the AuPd capsule2. The second method gives values that are in good agreement with established buffer whereas results from the first method are one half to one log units higher than the established values. References 1. E. Medard, C. A. McCammon, J. A. Barr, T. L. Grove, Am. Mineral. 93, 1838 (2008). 2. J. Barr, T. Grove, Contrib. Mineral. Petrol. 160, 631 (2010)

Eco-environmental impact assessment of pre-leisure beach nourishment on the benthic invertebrate community at Anping coast

NASA Astrophysics Data System (ADS)

Shih, Chun-Han; Kuo, Yi-Yu; Chu, Ta-Jen; Chou, Wen-Chieh; Chang, Wei-Tse; Lee, Ying-Chou

2011-06-01

In recent years, owing to global warming and the rising sea levels, beach nourishment and groin building have been increasingly employed to protect coastal land from shoreline erosion. These actions may degrade beach habitats and reduce biomass and invertebrate density at sites where they were employed. We conducted an eco-environmental evaluation at the Anping artificial beach-nourishment project area. At this site, sand piles within a semi-enclosed spur groin have been enforced by use of eco-engineering concepts since 2003. Four sampling sites were monitored during the study period from July 2002 to September 2008. The environmental impact assessment and biological investigations that we conducted are presented here. The results from this study indicate that both biotic (number of species, number of individual organisms, and Shannon-Wiener diversity) and abiotic parameters (suspended solids, biological oxygen demand, chemical oxygen demand, dissolved inorganic nitrogen, dissolved inorganic phosphorus, total phosphorus, total organic carbon, median diameter, and water content) showed significant differences before and after beach engineering construction. Biological conditions became worse in the beginning stages of the engineering but improved after the restoration work completion. This study reveals that the composition of benthic invertebrates changed over the study period, and two groups of organisms, Bivalvia and Gastropoda, seemed to be particularly suitable to this habitat after the semi-enclosed artificial structures completion.

Modelling of dissolved oxygen content using artificial neural networks: Danube River, North Serbia, case study.

PubMed

Antanasijević, Davor; Pocajt, Viktor; Povrenović, Dragan; Perić-Grujić, Aleksandra; Ristić, Mirjana

2013-12-01

The aims of this study are to create an artificial neural network (ANN) model using non-specific water quality parameters and to examine the accuracy of three different ANN architectures: General Regression Neural Network (GRNN), Backpropagation Neural Network (BPNN) and Recurrent Neural Network (RNN), for prediction of dissolved oxygen (DO) concentration in the Danube River. The neural network model has been developed using measured data collected from the Bezdan monitoring station on the Danube River. The input variables used for the ANN model are water flow, temperature, pH and electrical conductivity. The model was trained and validated using available data from 2004 to 2008 and tested using the data from 2009. The order of performance for the created architectures based on their comparison with the test data is RNN > GRNN > BPNN. The ANN results are compared with multiple linear regression (MLR) model using multiple statistical indicators. The comparison of the RNN model with the MLR model indicates that the RNN model performs much better, since all predictions of the RNN model for the test data were within the error of less than ± 10 %. In case of the MLR, only 55 % of predictions were within the error of less than ± 10 %. The developed RNN model can be used as a tool for the prediction of DO in river waters.

Effect of temperature and dissolved oxygen on stress corrosion cracking behavior of P92 ferritic-martensitic steel in supercritical water environment

NASA Astrophysics Data System (ADS)

Zhang, Z.; Hu, Z. F.; Zhang, L. F.; Chen, K.; Singh, P. M.

2018-01-01

The effect of temperature and dissolved oxygen (DO) on stress corrosion cracking (SCC) of P92 martensitic steel in supercritical water (SCW) was investigated using slow strain rate test (SSRT) and fractography analysis. The SSRT was carried out at temperatures of 400, 500, 600 °C in deaerated supercritical water and at DO contents of 0, 200, 500 ppb at the temperature of 600 °C, respectively. The results of SSRT show that the decrease of ductility at the temperature of 400 °C may be related to the dynamic strain aging (DSA) of P92 steel. The degradation of the mechanical properties in SCW is the joint effect of temperature and SCC. Compared with the effect of temperature, DO in SCW has no significant effect on the SCC susceptibility of P92 steel. The observation of oxide layer shows that large numbers of pores are nucleated in the oxide layer, which is related to vacancy accumulation and hydrogen generated in the oxide layer. Under the combined action of the growth stress and tensile stress, micro cracks, nucleated from the pores in the oxide layer, are easily propagated intergranularly outward to the surface of specimen, and fewer cracks can extend inward along the intrinsic pores to the inner oxide/metal interface, which is the reason for the exfoliation of oxide films.

Quality analysis, miceller behavior, and environmental impact of some laundry detergents available in Bangladesh.

PubMed

Nur-E-Alam, M; Islam, M Monirul; Islam, M Nazrul; Rima, Farhana Rahman; Islam, M Nurul

2016-03-01

The cleansing efficiencies of laundry detergents depend on composition and variation of ingredients such as surfactants, phosphate, and co-builders. Among these ingredients, surfactants and phosphate are considered as hazardous materials. Knowledge on compositions and micellar behavior is very useful for understanding their cleansing efficiencies and environmental impact. With this view, composition, critical micelle concentration, and dissolved oxygen level in aqueous solution of some laundry detergents available in Bangladesh such as keya, Wheel Power White, Tibet, Surf Excel, and Chaka were determined. Surfactant and phosphate were found to be maximum in Surf Excel and Wheel Power White, respectively, while both of the ingredients were found to be minimum in Tibet. The critical micelle concentration decreased with increasing surfactant content. The amount of laundry detergents required for efficient cleansing was found to be minimum for Surf Excel and maximum for Chaka; however, cleansing cost was the highest for Surf Excel and the lowest for Tibet. The maximum amount of surfactants and phosphate was discharged by Surf Excel and Wheel Power White, respectively, while discharges of both of the ingredients were minimum for Tibet. The maximum decrease of dissolved oxygen level was caused by Surf Excel and the minimum by Tibet. Therefore, it can be concluded that Tibet is cost-effective and environment friendly, whereas Surf Excel and Wheel Power White are expensive and pose a threat to water environment.

Relation of desert pupfish abundance to selected environmental variables in natural and manmade habitats in the Salton Sea basin

USGS Publications Warehouse

Martin, B.A.; Saiki, M.K.

2005-01-01

We assessed the relation between abundance of desert pupfish, Cyprinodon macularius, and selected biological and physicochemical variables in natural and manmade habitats within the Salton Sea Basin. Field sampling in a natural tributary, Salt Creek, and three agricultural drains captured eight species including pupfish (1.1% of the total catch), the only native species encountered. According to Bray-Curtis resemblance functions, fish species assemblages differed mostly between Salt Creek and the drains (i.e., the three drains had relatively similar species assemblages). Pupfish numbers and environmental variables varied among sites and sample periods. Canonical correlation showed that pupfish abundance was positively correlated with abundance of western mosquitofish, Gambusia affinis, and negatively correlated with abundance of porthole livebearers, Poeciliopsis gracilis, tilapias (Sarotherodon mossambica and Tilapia zillii), longjaw mudsuckers, Gillichthys mirabilis, and mollies (Poecilia latipinnaandPoecilia mexicana). In addition, pupfish abundance was positively correlated with cover, pH, and salinity, and negatively correlated with sediment factor (a measure of sediment grain size) and dissolved oxygen. Pupfish abundance was generally highest in habitats where water quality extremes (especially high pH and salinity, and low dissolved oxygen) seemingly limited the occurrence of nonnative fishes. This study also documented evidence of predation by mudsuckers on pupfish. These findings support the contention of many resource managers that pupfish populations are adversely influenced by ecological interactions with nonnative fishes. ?? Springer 2005.

Effect of hemoglobin polymerization on oxygen transport in hemoglobin solutions.

PubMed

Budhiraja, Vikas; Hellums, J David

2002-09-01

The effect of hemoglobin (Hb) polymerization on facilitated transport of oxygen in a bovine hemoglobin-based oxygen carrier was studied using a diffusion cell. In high oxygen tension gradient experiments (HOTG) at 37 degrees C the diffusion of dissolved oxygen in polymerized Hb samples was similar to that in unpolymerized Hb solutions during oxygen uptake. However, in the oxygen release experiments, the transport by diffusion of dissolved oxygen was augmented by diffusion of oxyhemoglobin over a range of oxygen saturations. The augmentation was up to 30% in the case of polymerized Hb and up to 100% in the case of unpolymerized Hb solution. In experiments performed at constant, low oxygen tension gradients in the range of physiological significance, the augmentation effect was less than that in the HOTG experiments. Oxygen transport in polymerized Hb samples was approximately the same as that in unpolymerized samples over a wide range of oxygen tensions. However, at oxygen tensions lower than 30 mm Hg, there were more significant augmentation effects in unpolymerized bovine Hb samples than in polymerized Hb. The results presented here are the first accurate, quantitative measurements of effective diffusion coefficients for oxygen transport in hemoglobin-based oxygen carriers of the type being evaluated to replace red cells in transfusions. In all cases the oxygen carrier was found to have higher effective oxygen diffusion coefficients than blood.