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Dissolved oxygen plays a central role for all organisms dwelling in water. However, the flux of oxygen by ebullition has not received much attention in environmental science. For a better quantitative understanding of the oxygen flux due to ebullition, we conducted a series of laboratory experiments, where we forced macrophytes to produce photosynthetic gas bubbles. Raising the CO2 concentration in the water greatly increased bubble formation. Depth was varied to compare the results with theoretically predicted composition of photosynthetic bubbles forming at minimum required gas pressure. Oxygen concentrations lay between this theoretical line as lower boundary (ca. 21% O2 at 0.3 m depth and 45% of O2 at 4.5 m) and 45% of oxygen as the purely empirical upper limit for all depths. As a consequence, no bubble formation was observed at depths below 4.5 m.

By hosting significant amounts of extra-atmospheric dissolved gases, including geogenic CO2 and CH4, volcanic lakes provide relevant ecosystem services through the key role the aquatic microbial community in mediating freshwater carbon fluxes. In view of elucidating the mechanisms governing the microbial spatial distribution and the possible implications for ecosystem functioning, we compared the hydrogeochemical features and the microbial community structure of two adjacent stratified volcanic lakes (Lake Grande - LG and Lake Piccolo - LP). Water chemistry, gases and their isotopic composition were coupled with microbial pigment profiling, cell counting, and phylogenetic analyses. LP showed transparent waters with low concentrations of chlorophyll-a and the occurrence of phycoerytrin-rich cyanobacteria. LG was relatively more eutrophic with a higher occurrence of diatoms and phycocyanine-rich cyanobacteria. Considering the higher concentrations of CO2 and CH4 in bottom waters, the oligotrophic LP was likely a more efficient sink of geogenic CO2 in comparison to the adjacent eutrophic LG. The prokaryotic community was dominated by the mixothrophic hgcI clade (family Sporichthyaceae) in the LG surface waters, while in LP this taxon was dominant down to -15 m. Moreover, in LP, the bottom dark waters harbored a unique strictly anaerobic bacterial assemblage associated with methanogenic Archaea (i.e. Methanomicrobiales), resulting in a high biogenic methane concentration. Water layering and light penetration were confirmed as major factors affecting the microbial distribution patterns. The observed differences in the geochemical and trophic conditions reflected the structure of the aquatic microbial community, with direct consequences on the dynamics of dissolved greenhouse gases.

This dataset consists of the GLODAPv2.2023 data product composed of data from 1108 scientific cruises covering the global ocean between 1972 and 2021. It includes full depth discrete bottle measurements of salinity, oxygen, nitrate, silicate, phosphate, dissolved inorganic carbon (TCO2), total alkalinity (TAlk), CO2 fugacity (fCO2), pH, chlorofluorocarbons (CFC-11, CFC-12, CFC-113, and CCl4), SF6, and various isotopes and organic compounds. It was created by appending data from 23 cruises to GLODAPv2.2022 (Lauvset et al., 2022, NCEI Accession 0257247). The data for salinity, oxygen, nitrate, silicate, phosphate, TCO2, TAlk, pH, CFC-11, CFC-12, CFC-113, CCl4, and SF6 were subjected to primary and secondary quality control. Severe biases in these data have been corrected for, and outliers removed. However, differences in data related to any known or likely time trends or variations have not been corrected for. These data are believed to be accurate to 0.005 in salinity, 1% in oxygen, 2% in nitrate, 2% in silicate, 2% in phosphate, 4 µmol kg-1 in TCO2, 4 µmol kg-1 in TAlk, and for the halogenated transient tracers and SF6: 5%

© The Author(s), 2020. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Wheat, C. G., Seewald, J. S., & Takai, K. Fluid transport and reaction processes within a serpentinite mud volcano: South Chamorro Seamount. Geochimica Et Cosmochimica Acta, 269, (2020): 413-428, doi: 10.1016/j.gca.2019.10.037, Natural fluids with a pH (25 °C) up to 12.3 were collected from a sub-seafloor borehole observatory (Ocean Drilling Program (ODP) Hole 1200C) on South Chamorro Seamount, a serpentinite mud volcano in the Mariana forearc. We used systematic differences in the chemical compositions of pore waters from drilling operations during ODP Leg 195 and borehole fluids collected subsequently from Hole 1200C to define two endmember solutions, one of which was a sulfate-rich fluid with a methane concentration of 50 mM that ascends from the subduction channel and the other was a low-sulfate fluid. The sequence of sample collection and fluid compositions constrain subsurface hydrologic conditions. Deep-sourced, sulfate- and methane-rich, sterile fluids from the subduction channel can reach the seafloor unchanged within the central conduit, whereas other fluid pathways likely intersect the pelagic sediment that underlies the serpentinite mud volcano, providing potentially suitable conditions and inoculum for microbial anaerobic oxidation of methane (AOM). These AOM-affected, low-sulfate fluids also make it to the seafloor where they discharge. The source of the sulfate- and methane-rich fluid in the subduction channel is attributed to abiotic methane production fueled by hydrogen production from serpentinization and carbonate dissolution. This methane production includes a mechanism to raise the pH above values from serpentinization alone. Results from South Chamorro Seamount represent an end member along a transect defined by the distance from the trench. Results from this site are applied to other serpentinite mud volcanoes along this transect to speculate on likely chemical conditions within shallower and cooler portions of the subduction channel., The authors thank the entire shipboard parties of cruises NT09-01 and NT09-07 on the R/V Nastushima and the crews and pilots of the ROV HyperDolphin. We also thank Tom Pettigrew for removing the dummy plug and designing the insert for the borehole. This research was supported by the National Science Foundation (OCE-0727120 and 1439564 (CGW) and OCE--0725204 (JS)) and the Japan Agency for Marine-Earth Science and Technology. This is C-DEBI contribution 497.

© The Author(s), 2020. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Wheat, C. G., Seewald, J. S., & Takai, K. Fluid transport and reaction processes within a serpentinite mud volcano: South Chamorro Seamount. Geochimica Et Cosmochimica Acta, 269, (2020): 413-428, doi: 10.1016/j.gca.2019.10.037, Natural fluids with a pH (25 °C) up to 12.3 were collected from a sub-seafloor borehole observatory (Ocean Drilling Program (ODP) Hole 1200C) on South Chamorro Seamount, a serpentinite mud volcano in the Mariana forearc. We used systematic differences in the chemical compositions of pore waters from drilling operations during ODP Leg 195 and borehole fluids collected subsequently from Hole 1200C to define two endmember solutions, one of which was a sulfate-rich fluid with a methane concentration of 50 mM that ascends from the subduction channel and the other was a low-sulfate fluid. The sequence of sample collection and fluid compositions constrain subsurface hydrologic conditions. Deep-sourced, sulfate- and methane-rich, sterile fluids from the subduction channel can reach the seafloor unchanged within the central conduit, whereas other fluid pathways likely intersect the pelagic sediment that underlies the serpentinite mud volcano, providing potentially suitable conditions and inoculum for microbial anaerobic oxidation of methane (AOM). These AOM-affected, low-sulfate fluids also make it to the seafloor where they discharge. The source of the sulfate- and methane-rich fluid in the subduction channel is attributed to abiotic methane production fueled by hydrogen production from serpentinization and carbonate dissolution. This methane production includes a mechanism to raise the pH above values from serpentinization alone. Results from South Chamorro Seamount represent an end member along a transect defined by the distance from the trench. Results from this site are applied to other serpentinite mud volcanoes along this transect to speculate on likely chemical conditions within shallower and cooler portions of the subduction channel., The authors thank the entire shipboard parties of cruises NT09-01 and NT09-07 on the R/V Nastushima and the crews and pilots of the ROV HyperDolphin. We also thank Tom Pettigrew for removing the dummy plug and designing the insert for the borehole. This research was supported by the National Science Foundation (OCE-0727120 and 1439564 (CGW) and OCE--0725204 (JS)) and the Japan Agency for Marine-Earth Science and Technology. This is C-DEBI contribution 497.

Experimental and ambient warming of Arctic tundra results in emissions of greenhouse gases to the atmosphere, contributing to a positive feedback to climate warming. Estimates of gas emissions from lakes and terrestrial tundra confirm the significance of aquatic fluxes in greenhouse gas budgets, whereas few estimates describe emissions from fluvial networks. We measured dissolved gas concentrations and estimated emissions of carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O) from water tracks, vegetated depressions that hydrologically connect hillslope soils to lakes and streams. Concentrations of trace gases generally increased as ground thaw deepened through the growing season, indicating active production of greenhouse gases in thawed soils. Wet antecedent conditions were correlated with a decline in CO2 and CH4 concentrations. Dissolved N2O in excess of atmospheric equilibrium occurred in drier water tracks, but on average water tracks took up N2O from the atmosphere at low rates. Estimated CO2 emission rates for water tracks were among the highest observed for Arctic aquatic ecosystems, whereas CH4 emissions were of similar magnitude to streams. Despite occupying less than 1% of total catchment area, surface waters within water tracks were an estimated source of up to 53–85% of total CH4 emissions from their catchments and offset the terrestrial C sink by 5–9% during the growing season. Water tracks are abundant features of tundra landscapes that contain warmer soils and incur deeper thaw than adjacent terrestrial ecosystems and as such might contribute to ongoing and accelerating release of greenhouse gases from permafrost soils to the atmosphere.

Author Posting. © American Geophysical Union, 2017. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research: Oceans 122 (2017): 1901–1926, doi:10.1002/2016JC012306., Photosynthetic conversion of inline image to organic carbon and the transport of this carbon from the surface to the deep ocean is an important regulator of atmospheric inline image. To understand the controls on carbon fluxes in a productive region impacted by upwelling, we measured biological productivity via multiple methods during a cruise in Monterey Bay, California. We quantified net community production and gross primary production from measurements of inline image/Ar and inline image triple isotopes ( inline image), respectively. We simultaneously conducted incubations measuring the uptake of 14C, inline image, and inline image, and nitrification, and deployed sediment traps. At the start of the cruise (Phase 1) the carbon cycle was at steady state and the estimated net community production was 35(10) and 35(8) mmol C m−2 d−1 from inline image/Ar and 15N incubations, respectively, a remarkably good agreement. During Phase 1, net primary production was 96(27) mmol C m−2 d−1 from C uptake, and gross primary production was 209(17) mmol C m−2 d−1 from inline image. Later in the cruise (Phase 2), recently upwelled water with higher nutrient concentrations entered the study area, causing 14C and inline image uptake to increase substantially. Continuous inline image/Ar measurements revealed submesoscale variability in water mass structure and likely productivity in Phase 2 that was not evident from the incubations. These data demonstrate that inline image/Ar and inline image incubation-based NCP estimates can give equivalent results in an N-limited, coastal system, when the nonsteady state inline image fluxes are negligible or can be quantified., Funding for this work was provided by NSF awards OCE-1060840 to R.H.R. Stanley, OCE-1129644 to D.P. Nicholson, OCE-1357042 to F.P. Chavez, NASA award NNX14AI06G to M.R. Fewings, the David and Lucile Packard Foundation through their generous annual donation to the Monterey Bay Aquarium Research Institute, an Ocean Ventures Fund award from the WHOI Academic Programs Office to CC Manning, and graduate scholarships from NSERC and CMOS to CC Manning., 2017-09-11

Author Posting. © American Geophysical Union, 2017. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research: Oceans 122 (2017): 1901–1926, doi:10.1002/2016JC012306., Photosynthetic conversion of inline image to organic carbon and the transport of this carbon from the surface to the deep ocean is an important regulator of atmospheric inline image. To understand the controls on carbon fluxes in a productive region impacted by upwelling, we measured biological productivity via multiple methods during a cruise in Monterey Bay, California. We quantified net community production and gross primary production from measurements of inline image/Ar and inline image triple isotopes ( inline image), respectively. We simultaneously conducted incubations measuring the uptake of 14C, inline image, and inline image, and nitrification, and deployed sediment traps. At the start of the cruise (Phase 1) the carbon cycle was at steady state and the estimated net community production was 35(10) and 35(8) mmol C m−2 d−1 from inline image/Ar and 15N incubations, respectively, a remarkably good agreement. During Phase 1, net primary production was 96(27) mmol C m−2 d−1 from C uptake, and gross primary production was 209(17) mmol C m−2 d−1 from inline image. Later in the cruise (Phase 2), recently upwelled water with higher nutrient concentrations entered the study area, causing 14C and inline image uptake to increase substantially. Continuous inline image/Ar measurements revealed submesoscale variability in water mass structure and likely productivity in Phase 2 that was not evident from the incubations. These data demonstrate that inline image/Ar and inline image incubation-based NCP estimates can give equivalent results in an N-limited, coastal system, when the nonsteady state inline image fluxes are negligible or can be quantified., Funding for this work was provided by NSF awards OCE-1060840 to R.H.R. Stanley, OCE-1129644 to D.P. Nicholson, OCE-1357042 to F.P. Chavez, NASA award NNX14AI06G to M.R. Fewings, the David and Lucile Packard Foundation through their generous annual donation to the Monterey Bay Aquarium Research Institute, an Ocean Ventures Fund award from the WHOI Academic Programs Office to CC Manning, and graduate scholarships from NSERC and CMOS to CC Manning., 2017-09-11

Seismic-volcanic unrest was detected between 2004 and 2005 in the central and northwest zones of Tenerife Island (Canary Islands, Spain). With the aim of strengthening the program of geochemical and seismic-volcanic surveillance, a study of the origin, characteristics, and spatial distribution of dissolved carbon dioxide (CO2) and helium (He) gases in the volcanic aquifer of central Tenerife Island and around Teide volcano was carried out. This work also improves the hydrogeological and hydrogeochemical conceptual model of groundwater flow. Dissolved CO2 concentrations in sampled groundwater are several orders of magnitude higher than that of air-saturated water (ASW) suggesting a significant contribution of non-atmospheric CO2, mainly magmatic, confirmed through measurement of isotopic compositions (delta C-13(TDIC)) and total dissolved inorganic carbon (TDIC) concentrations. A vertical stratification of dissolved CO2 and delta C-13(TDIC) values was observed in the volcanic aquifer at the eastern region of Las Canadas Caldera. Stratification seems to be controlled by both degree of magmatic CO2-water interaction and CO2 degassing and the original delta C-13(co2(g)) isotopic composition. The highest dissolved helium (He-4) concentrations in groundwater seem to be related to radiogenic contributions resulting from water-rock interactions, and increase with residence time, instead of with endogenous magmatic inputs. Isotopic systematics show that the dissolved gases in groundwater of central Tenerife are variable mixtures of CO2-He-3-rich fluids of volcanic-hydrothermal origin with both organic and atmospheric components. The results suggest that the eastern area of Las Canadas Caldera, the South Volcanic Ridge, and the Teide summit cone are the areas most affected by degassing of the volcanic-hydrothermal system, and they are therefore the most suitable zones for future geochemical monitoring., Peer Reviewed, Postprint (published version)

This project demonstrated a paradigm for assessing source zone natural attenuation (SZNA) at chlorinated aliphatic hydrocarbon (CAH) impacted sites. SZNA is often used as a basis for assessing the performance and relative benefits of engineered remediation and is also a component of the cleanup strategy at most CAH-impacted sites. Thus there is a need for a well-defined and accepted assessment approach. The data-driven method anticipates that decision makers will be interested in the following questions: 1-Is SZNA occurring and what processes contribute?; 2-What are the current SZNA rates?; and 3-What are the longer-term implications of SZNA? The approach uses multiple lines-of-evidence and macroscopic mass balances, and these lead to confirmation of SZNA and quantification of the total mass loss rate resulting from degradation, dissolved phase transport, and volatilization. Application of the approach was demonstrated at three CAH impacted sites through four events per site over about three years. The mass loss rates were relatively consistent over time for each site, but varied from site to site, ranging between about 1 10 kg/y at two sites and as high as about 600 kg/y at the third site. When applying the generalized CAH-SZNA method, it is likely that different practitioners will choose the number and locations of samples in different ways. For example, this could happen at a site over different sampling events. This then raises the question: Is the calculated SZNA mass loss rate likely to be dependent on the sampling strategy?, and if so, how should sampling plans be designed to ensure consistency in results across practitioners? As a result, the high spatial-density data collected from the demonstration sites in this project were used to examine the effect of different sampling strategies on the quantification of mass loss rates at those sites. That experience, and lessons-learned from previously published studies on this topic, were used as the basis for new, Prepared in collaboration with LundegardUSA and IST.

The effect of dissolved gas on the reversibility of a Li/Li+ electrode in an ionic liquid electrolyte was investigated. Lithium metal is a potential anode in lithium batteries. The ionic liquid electrolyte was saturated with argon, nitrogen, oxygen, air, or carbon dioxide and the coulombic efficiency for the reduction and reoxidation of lithium metal was measured. Secondary ion mass spectroscopy (SIMS) was used to determine the thickness and composition of the solid electrolyte interphase (SEI) layer formed on the lithium metal. The coulombic cycling efficiency was highest with oxygen, nitrogen, and air. The coulombic efficiency was significantly lower with dissolved carbon dioxide. SIMS revealed that the SEI layer was made up of primarily LiF regardless of the gas used. The thickness of the SEI layer was the main determinant of cycling efficiency. A thinner SEI, observed with nitrogen and oxygen, lead to the highest coulombic efficiency, whereas, carbon dioxide produced a thick SEI which appeared to inhibit lithium deposition., journal of physical chemistry

Two E. coli BW28357 hosts (one with pyk A mutation and one without) harboring the same PMO plasmid were used in a 20-L scale-up fermentation process to compare the effect of pyk A mutation in propane to propanol biotransformation yield. Also, one additional 20-L fermentation run with E. coli BW28357 without pyk A mutation was conducted without IPTG induction to serve as a baseline in terms of cell yield and dissolved oxygen profile. The same media and operating conditions were used for each three runs. For the two IPTG induced runs, the same timing (around 4.5 hr into fermentation w/optical density of approximately 0.8) was used. No significant differences in dissolved oxygen profiles and final optical density in each fermentation run (approximately 10) were observed. The levels of expressed PM-450 were significant and similar at approximately 30% of the total cellular proteins. However, low propanol yields of approximately 2 mM for both fermentation runs, which represented only 0.0017% of the total gaseous propane fed during the course of each fermentation run, indicated a low catalytic turnover rate of the expressed P450 BM-3 enzymes., Prepared in collaboration with Science Applications International Corp., Gunpowder, MD.

In Lake Francis Case, water is routed to the dam intake structure through a submerged approach channel that connects to the old Missouri River channel (Figure 1). The invert elevation (i.e., 1229 ft-msl) of the intake for the power tunnels at Fort Randall Dam is 2 feet above the bottom of the approach channel. Thermal stratification that develops in Lake Francis Case during the summer results in a significant water density gradient between the epilimnion and hypolimnion. Due to the water density gradient, restricted approach channel, and bottom withdrawal, the vertical extent that water is withdrawn from Lake Francis Case in the summer is dependent upon the discharge rate of the dam. During periods of lower flows through the powerplant water is pulled from lower elevations along the bottom of the reservoir. Higher powerplant flows are believed to create enough turbulence near the dam intake structure to allow warmer, less dense water to be drawn from higher elevations in Lake Francis Case. Degradation of dissolved oxygen occurs in the quiescent hypolimnion of Lake Francis Case during summer thermal stratification. Dissolved oxygen degradation is greatest near the reservoir bottom and expands upward in the water column as summer thermal stratification continues. Past water quality monitoring indicates that the lower depths of Lake Francis Case typically degrade to hypoxic conditions by early July. At that time, a heightened potential exists for hypoxic water to be drawn into the powerplant and discharged downstream to the Missouri River. The discharge of hypoxic water could result in dissolved oxygen conditions in the Fort Randall tailwaters not meeting South Dakota s water quality standards minimum criteria for dissolved oxygen., Report no. CENWO ED HA/SSR/Fort Randall Tailwaters/2010.

This report documents a study of environmental conditions and habitat quality of replicated pond ecosystems dominated by populations of exotic plants or mixed communities of native aquatic plants. Study ponds were similar in depth, size, and shape, as well as in (initial) water and sediment composition. The study design called for two phases, the first to evaluate developing plant communities, and the second to evaluate mature plant communities. This report details first year results of developing plant communities., Aquatic Plant Control Research Program. Prepared in cooperation with the Institute of Applied Science, University of North Texas, Denton, TX. The original document contains color images.

The objectives for this project were diverse, including underwater mass spectrometer (MS) deployments focusing on quantitative measurements of dissolved gases, and improvements on existing 200-amu systems and peripherals. Plume mapping capabilities were to be extended by integrating the underwater MS with a remotely operated vehicle (ROV), and by exploring methods to mathematically improve the spatial and temporal resolution of membrane introduction MS measurements. Instrumental developments (e.g., a novel, modular, deep-water syringe sampling pump system) were to further extend the analytical capabilities of the systems. In-line acidification methods were to be explored to more thoroughly study aqueous carbon systems in the field. Alternative membrane materials, such as carbon nanotubes, were also to be evaluated. Major accomplishments in each of these areas of research and development are discussed below., The original document contains color images.

This report documents the development of the PAR3D numerical flow model, with emphasis on modifications incorporated to facilitate simulations of contaminant dispersion in complex buildings and other enclosures. PAR3D is a general-purpose computational fluid dynamics (CFD) code for predicting three-dimensional flow and transport in air, water, and other incompressible fluids. It includes a two-equation turbulence model with adjustments for buoyancy, as well as transport equations for suspended materials (contaminants), dissolved gases, and gas bubbles (in water). The code employs parallel processing with structured curvilinear grids, which may deform to accommodate quasistatic free-surface displacement in water. The CFD applications included here concern air flow and aerosol dispersion inside two different man-made enclosures. These consist of single chambers with complex internal geometry, but PAR3D is applicable to multi-chamber enclosures as well. The reported developments are part of a larger computational and experimental effort to characterize the dispersion of contaminants in multi-room, multi-story buildings. Comparison of PAR3D predictions with experimental data from a multiroom test facility will be presented in a separate report., The original document contains color images.

We used a dynamic mixed layer model to determine carbon export by the oxygen mass balance method from a time series of O2/Ar, N2/Ar and Ne measurements collected at station ALOHA near Hawaii from July 2000 to June 2001. The inert gas measurements constrain the flux of oxygen into the mixed layer from small, collapsing bubbles (injection) to be greater than or equal to the flux from larger bubbles (exchange), with mean estimates of the ratio in the range of 1–2. We also show that monthly observations of temperature and inert gases cannot constrain the rate of diapycnal mixing at this location, because of uncertainties in air-sea heat flux estimates and bubble dynamics. Organic carbon export from the mixed layer calculated from our dataset was 1.1 ± 0.5 mol C m–2 yr–1, with most of the error deriving from uncertainties in the parameterization of diffusive gas exchange with wind speed. Our estimates of carbon export from the zone beneath the mixed layer but still in the euphotic zone ranged from 0 to 0.6 mol C m–2 yr–1 as the rate of background diapycnal mixing was increased from 0.1 to 1.0 cm2 s–1. We conclude that the oxygen mass balance method has errors of about a factor of two in areas similar to the subtropical North Pacific, with the main uncertainties deriving from mixing rates and the parameterization of diffusive gas exchange.

We used a dynamic mixed layer model to determine carbon export by the oxygen mass balance method from a time series of O2/Ar, N2/Ar and Ne measurements collected at station ALOHA near Hawaii from July 2000 to June 2001. The inert gas measurements constrain the flux of oxygen into the mixed layer from small, collapsing bubbles (injection) to be greater than or equal to the flux from larger bubbles (exchange), with mean estimates of the ratio in the range of 1–2. We also show that monthly observations of temperature and inert gases cannot constrain the rate of diapycnal mixing at this location, because of uncertainties in air-sea heat flux estimates and bubble dynamics. Organic carbon export from the mixed layer calculated from our dataset was 1.1 ± 0.5 mol C m–2 yr–1, with most of the error deriving from uncertainties in the parameterization of diffusive gas exchange with wind speed. Our estimates of carbon export from the zone beneath the mixed layer but still in the euphotic zone ranged from 0 to 0.6 mol C m–2 yr–1 as the rate of background diapycnal mixing was increased from 0.1 to 1.0 cm2 s–1. We conclude that the oxygen mass balance method has errors of about a factor of two in areas similar to the subtropical North Pacific, with the main uncertainties deriving from mixing rates and the parameterization of diffusive gas exchange.

We describe an analytical method with improved precision for measuring the concentration of neon dissolved in water. Measurements were calibrated by isotope dilution, with addition of a Ne-22 spike directly to the evacuated sample flask prior to water collection. The use of glass flasks for water sampling, with flushing of air from the system by CO2, greatly reduced the chance of contamination. Dissolved gases were extracted from the water sample by equilibration with a headspace and cryogenically processed to remove interferences. The Ne-22/Ne-20 ratio was then measured on a quadrupole mass spectrometer operated in static mode. Mass fractionation by the system was accounted for by frequent analyses of the Ne-22/Ne-20 ratio in air. We routinely obtained precisions of +/-0.13% based on the standard deviation of duplicate field samples. Accuracy of the method, in the form of possible systematic offsets that could skew all the data, was assessed to be +/-0.18%, excluding a possible +/-0.2% error in the estimate of the Ne concentration of air. (C) 2004 Elsevier B.V. All rights reserved.

We describe an analytical method with improved precision for measuring the concentration of neon dissolved in water. Measurements were calibrated by isotope dilution, with addition of a Ne-22 spike directly to the evacuated sample flask prior to water collection. The use of glass flasks for water sampling, with flushing of air from the system by CO2, greatly reduced the chance of contamination. Dissolved gases were extracted from the water sample by equilibration with a headspace and cryogenically processed to remove interferences. The Ne-22/Ne-20 ratio was then measured on a quadrupole mass spectrometer operated in static mode. Mass fractionation by the system was accounted for by frequent analyses of the Ne-22/Ne-20 ratio in air. We routinely obtained precisions of +/-0.13% based on the standard deviation of duplicate field samples. Accuracy of the method, in the form of possible systematic offsets that could skew all the data, was assessed to be +/-0.18%, excluding a possible +/-0.2% error in the estimate of the Ne concentration of air. (C) 2004 Elsevier B.V. All rights reserved.

Chlorinated aliphatic hydrocarbons (CAHs) are proving to be one of the most widespread, recalcitrant constituents of concern (COC) encountered in the age of environmental awareness. This class of compounds includes widely used solvents such as carbon tetrachloride (CT), methylene chloride, trichloroethane (TCA), trichloroethene (TCE) and tetrachloroethene (PCE). In addition to their roles in many industrial processes, CAHs have historically been used for cleaning and degreasing such diverse products as aircraft engines, automobile parts, electronic components and clothing in both the military and civilian sectors. Contamination of groundwater by mobile metals (e.g., chromium, lead, arsenic, nickel, mercury and cadmium) is also widespread at the same military facilities due to the use of these metals in ordnance, armament, armor, and as components of corrosion prevention coatings on vehicles. Both the number and complexity of sites impacted by CAHs and the threat to human and ecological health represented by this class of anthropogenic chemicals have resulted in mounting costs for the implementation of conventional remediation methods. This is related, in part, to the generally low solubility of the typical source solvents, and their tendency to sink in an aquifer after release or to adsorb to the aquifer materials. The more traditional remediation methods that rely on the extraction of groundwater will quickly reach an asymptotic state of mass removal and will be diffusion limited. In addition, risk based levels for TCE have been recently decreased in some jurisdictions making remediation more costly. As late as 1998, conventional remediation options for sites contaminated with CAHs were considered to be pump and treat with treatment consisting of air stripping, granular activated carbon adsorption, and ultraviolet oxidation (Nyer 1998)., Sponsored in part by the Environmental Security Technology Safety Program, Arlington, VA.

Long term goals for this project include deployment of mass spectrometers on network class autonomous underwater vehicles (AUVs) for in-situ detection, plus quantification and mapping of both volatile and non-volatile species in the water column. Ultimately we envision adaptation of our instruments as self-directed, true panoramic chemical sensors capable of, e.g., tracing dispersion of chemicals from point sources and investigating the evolution of reactive chemical species. The objective for this phase-one effort was to demonstrate, in the laboratory, the feasibility of using mass spectrometry as an underwater chemical sensor on an AUV. This effort was to include: a demonstration of the viability of mass spectrometry to detect compounds/elements of interest at concentrations found in the marine environment; construction of an interface for transporting analytes from solution phase to the vacuum of the mass spectrometer; evaluation of packaging requirements for deploying a mass spectrometer as an AUV payload; and development of a scheme for maintaining vacuum inside the mass spectrometer while underwater., See also ADM002252.

My long-term goal is to review creatively both our knowledge about the interaction of marine plankton with the hydrographic and chemical environment and the feedback from the planktonic processes to the abiotic environment. I use older observations and evaluations, as well as data collected by current programs. Understanding of the sea itself rather than the biology of marine organisms is being stressed., See also ADM002252.

This report covers the basic elements of industrial water treatment for heating and cooling systems. It explains the impurities found in water sources and what can be expected if untreated water is used in an industrial system. It contains information on how to initiate and maintain a water treatment program. Treatment chemicals are explained and methods to monitor, feed, and evaluate their effectiveness are also discussed.... Industrial water treatment, Dissolved gases, Dissolved minerals, Depositing producing organisms, Corrosion, Scale, Anode cathode, Corrosion coupons, Corrosion inhibitor, PH of saturation, Langelier saturation index, Ryznar stability index, Microbiological.

Most of the past work on the compression ignition sensitivity of liquid gun propellants did not succeed in elucidating the fundamental processes involved in compression ignition. Existing theoretical predictions rely on simplifying assumptions and remain unvalidated until appropriate experimental investigations are made. Recent experimental studies have focused on safety aspects and have tried to define reaction limits based on the ullage present, the bubble size, and the pressurization rate resulting in 'go or no-go' type of tests. Many of the tests have revealed, for cases where a compression ignition event was observed, a finite induction time before there is a significant pressure generation. There are five theoretical mechanisms (hot spot, impact (micro-jetting), chemical, cooperative effects, and oscillations) which may be involved during the ignition of a pressurized bubbly Lp and it is difficult to say which is the right one. Moreover, if one succeeds in discovering the mechanisms for ignition, adiabatic compression could be considered as a practical ignition source for a liquid propellant gun. Another important unknown in all of the adiabatic compression tests conducted to-date is the amount of dissolved gas in the propellant. For future tests, therefore, gas solubility measurements should be considered.

This dissertation on cavitation nucleation is concerned with both the cavitation nucleus and the mechanisms by which the nucleus is stabilized. The three most plausible theories of the cavitation nucleus are: the crevice model, the surfactant skin model, and the ionic skin model. The previous crevice model required that, in order for a vaporous cavity to grow from a crevice nucleus, the liquid gas interface must reach the receding contact angle. This condition is necessary but not sufficient. An additional criterion is that the radius of curvature of the interface must be greater than a critical radius, beyond which the cavity is mechanically unstable. Using these nucleation criteria, the model is rederived. Both old and new crevice models predict the cavitation threshold as a function of surface tension and temperature well. However, they diverge when predictions of the threshold as a function of dissolved gas content are considered. The old crevice model predicts a linear dependence but experiment shows the threshold increases rapidly with decreasing gas content. This behavior is predicted by the revised model. In addition to vaporous cavitation, the revised model is applied to diffusion cavitation and is shown to predict features present in the data previously explained only in terms of the varying- permeability model.

Instruments to measure dissolved gases were tested and evaluated under field conditions. Limitations and potential problems with the various instruments were discussed and recommendations were made. For dissolved oxygen (DO) measurements, instruments that use polarographic probes were recommended. Chemical titration techniques were recommended for probe calibration and spot-checking polarographic probe readings. The D'Aoust Tensionometer and WES Saturometer were recommended for measurements to determine dissolved nitrogen (DN) concentrations. These techniques were recommended because they proved easy to use and were reasonably reliable under field conditions. Although it provided simultaneous determinations of DO and DN, gas chromatography was not recommended for field measurements. The instruments were too sensitive to field handling, and results were very operator dependent.

A bench-scale, continuous flow, completely mixed activated sludge system was used to investigate the relationship of nitrification and other system parameters to heavy metal removal in the activated sludge waste treatment process. The heavy metals studied were chromium and silver. Analyses performed on the influent, mixed liquor, return sludge, and effluent included heavy metal concentration, pH, dissolved oxygen, temperature, suspended solids, chemical oxygen demand, nitrogen species, alkalinity, and other system control parameters. Results indicate that the sludge wasting rate is directly related to heavy metal removal. Nitrification is only indirectly related. A theory for the mechanisms contributing to heavy metal removal is developed.

Desinent cavitation data were obtained for confined water jets generated by a 5.08 cm (2 in.) diameter sharp-edged orifice and a contoured nozzle of the same diameter. Data were acquired over a range of total air content from 2.0 to 12.0 parts per million (mole basis) in water and a water polyox (WSR-301) solution of 100 parts per million (weight basis). The jet velocity was constant at 9.1 m/s (30 f/s). In general the polyox caused a reduction in the desinent cavitation index and the reduction increased with air content. However, below an air content of 4.0 ppm the desinent cavitation index is apparently independent of air content., Presented at the Cavitation and Polyphase Flow Forum, Joint Fluids Engineering and Gas Turbine Conference, New Orleans, La. 21-25 Mar 76. Pub. in Cavitation Forum Booklet.

The book discusses the chemical and microbiological processes taking place in reservoirs, tanks and ponds, and during purification of natural and sewage waters. Particular attention is devoted to problems of chemical and biological purification, in tensification of the methods of treating natural and sewage waters, new reagents and improvement of the treatment method. The textbook is designed for students at engineering-construction institutes with the specialty of 'Water Supply and Sewage Systems'. It will also be useful to engineering and technical personnel in studying, planning and operating water lines and sewage purification installations., Draft trans. of mono. Khimiia i Mikrobiologiia Vody, Kiev, 1971 306p.

A mathematical model was used to simulate the thermal and dissolved oxygen (D.O.) content of the proposed Falls Lake project and to evaluate the adequacy of the proposed multilevel intake structure for satisfying downstream temperature and D.O. objectives. The study indicated that proper operation of the proposed impoundment would result in satisfying the temperature objective. Low D.O. content values are predicted, reflecting the quality of water available for release through the intake structure and outlet works. However, reaeration of flow released through the multilevel outlet works should be sufficient to increase the D.O. content of the downstream release up to or above the desired minimum level of 5 mg/liter. (Author)

Measurements of dissolved hydrocarbon (C1-C4) as a function of the tidal cycle are reported. Measurements were made from 19 Sep to 5 Oct 1973 to evaluate a dissolved hydrocarbon monitoring system and to gain information about the behavior of dissolved pollutants in a tidal cycle. Sea water was pumped from 2-3 feet below the water level of New York Harbor and sprayed into a partially evacuated chamber where hydrocarbons were released as gases and subsequently transferred to a portable gas chromatograph for analysis. Generally, the monitoring system operated properly in the field with an experimental error of less than 20%. The trends of the relative data illustrate both the change in hydrocarbon concentration over the tidal cycle (as much as 6X) and the day-to-day variation of the coordinated tidal data. These data indicate that efficient and meaningful monitoring of dissolved pollutants can be accomplished best with an understanding of the tidal pattern of the pre-existing pollutants. Such background information is essential: (1) to determine a sampling window in the tidal cycle which will appropriately reflect the pollutant input relative to the pre-existing levels; (2) to interpret the extent and time frame of the increase due to the pollution incident; and (3) to interpret possible irregularities in the surveillance data obtained during the sampling window.

A preliminary investigation was undertaken to determine if a monitoring device capable of unattended operation could be configured to continuously measure total dissolved gases in natural waters. A three-component system was designed consisting of a pumping system, a continuous gas stripper, and a detector. Prototypes of the first two components were assembled and evaluated under field conditions. Based upon these results, it is possible to configure a monitor capable of unattended operation for continuous measurement of total dissolved gas concentrations in natural waters.

Sediments deposited in the channel by fluvial processes and material derived from the products of bank erosion pose a continuous dredging and disposal problem in the Mississippi River navigation system. Only a limited amount of data are available on the physical, chemical, and biological characteristics of the Middle Mississippi River as related to dredging and disposal operations. The study was undertaken: To provide background information on the physical, chemical, and biological characteristics of selected dredged and disposal sites; (2) to establish uniform procedures for sampling dredged material and biota in a riverine system; and (3) to describe the environmental impacts of dredging and disposal activities. Fifteen sites with prior histories of maintenance dredging and adjacent disposal operations and three river border areas with no history of dredging-disposal operations were sampled in September 1973.

The saturometer measures the total dissolved gas pressure present in solutions such as in rivers, lakes, and other water bodies. A di-methyl silicone rubber tubing, permeable to gases and water vapor, is immersed in the water and a precision pressure gauge coupled to the tubing measures the internal pressures produced by gas components diffusing into the bore through the membrane wall.

The patent concerns a method of detecting and measuring the quantity of a gas dissolved in a liquid. This comprises flowing a carrier gas for displacing the dissolved gas from the liquid over a flowing body of the liquid in a confined cylindrical zone at carrier gas-to-liquid ratios of from 10 to 1 through 1 to 2 and flow rates therefor of up to about 100 cc per minute, continuously lifting films of the liquid into and across the flowing carrier gas to effect displacement of the dissolved gas from the liquid and formation of a mixture of the carrier gas and displaced dissolved gas and flowing said mixed gas through an operating thermal conductivity cell to relate the thermal conductivity of said mixed gas to that of the carrier gas.

In order to prevent waterside corrosion of steam generating plants used by the Navy, it is necessary to remove the dissolved oxygen from the water. In most cases this is accomplished by mechanical deaeration. When the efficiency of the deaerator is reduced, however, or when oxygen (air) leaks occur, it is necessary to supplement the oxygen-removal process with chemical treatment. Small amounts of oxygen can be scavenged economically by adding a reducing agent, such as sodium sulfite, to the feedwater. The objective of the study was to increase the effectiveness of the use of sulfite as an oxygen scavenger in closed water systems. The chelating agent chosen was disodium ethylenediamine tetraacetate (Na2EDTA). Other inhibitors were also included in some of the experiments. The autoxidation of sodium sulfite was inhibited by the EDTA. Results of experiments show that, when ions of copper and iron are chelated with EDTA, they no longer catalyze the oxidation of Na2SO3.

The report gives the bio-environmental engineer, preventive medicine technician, or other personnel working in the field of water quality management a basic understanding of the parameters which are used to evaluate water quality. Water in any state is virtually 100 percent H2O. The classification as drinking water or waste water is only distinguishable through evaluation of the quality demanded or observed. Water will therefore be discussed here as an entity, with observations, where applicable, made as to its various qualities.

In the report account is given of the contemporary science of electric strength in liquid dielectrics. Experimental and theoretical data are presented on their breakdown. Processes connected with chlorodiphenyl are considered in a way which is useful for conditions which are encountered in application. Data are also presented on the electric strength of insulating mixtures and information on the change in the electrical and physical properties of certain insulation liquids subjected to radiation is also included. Furthermore, consideration is given to questions connected with the spark temperature at the time of an electric breakdown and the pressure in the discharge channel., Edited trans. of mono. Elektricheskaya Prochnost Zhidkikh Dielektrikov, n.p., 1964 p1-227.

Liquid wastes produced at Air Force bases require monitoring of their characteristics to ensure disposal in a nonpolluting manner. A market survey of commercially available wastewater sampling and monitoring equipment has been made. Information was gathered from vendors and directly from users by a questionnaire. A total oxygen demand analyzer, a fluoride monitor, and a dissolved oxygen analyzer/controller were field tested. Continuous on-line equipment of proven reliability was located and recommended for measuring conductivity, dissolved oxygen, hydraulic loading, ORP, pH, residual chlorine, temperature, and turbidity. Less acceptable continuous, automatic, or semi-automatic devices for measurement of a large number of parameters were found, but are recommended only where manual procedures are not feasible. Various types of samplers are discussed and recommendations are given. (Modified author abstract)

The report presents the results of the first year studies of a three year research contract to determine the environmental response to the deposition of dredged material on salt marshes using diked and undiked confinement techniques. The report includes studies of water quality changes, studies of salt marsh sediment responses, and biological studies directed toward identifying any changes in the biota in areas of dredging activities. (Author Modified Abstract)

Industrial waste activities at Griffiss AFB presently discharge waste water to Six Mile Creek and Three Mile Creek with minimal or no treatment. An industrial waste and stream sampling survey was conducted at Griffiss AFB to determine the magnitude of the pollution problem and to recommend abatement measures. It was determined that the quality of water in both creeks was impaired by the industrial waste discharges. To abate pollution from Griffiss AFB, recommendations have been made for each industrial waste source--mainly discharge to Rome, New York, sewage treatment plant through the base sanitary sewer system. (Author)

The Chesapeake Bay Institute (CBI) maintains a bank of information consisting of all oceanographic data collected by CBI on the Chesapeake Bay and its tributaries. Since 1949 CBI has gathered data both for specific projects and for general surveys. Much of it has been published as individual cruise reports (CBI Data Reports 1-50), but never collated in a way to make it generally accessible for secondary use. Recently a complete reorganization of this data bank was undertaken to promote better utilization of its contents. This report describes the contents of the Chesapeake Bay Tributaries portion of the CBI data bank. (Author), See also Volume 2, AD-761 184.

The Chesapeake Bay Institute (CBI) maintains a bank of information consisting of all oceanographic data collected by CBI on the Chesapeake Bay and its tributaries. Since 1949 CBI has gathered data both for specific projects and for general surveys. Much of it has been published as individual cruise reports (CBI Data Reports 1-50), but never collated in a way to make it generally accessible for secondary use. Recently a complete reorganization of this data bank was undertaken to promote better utilization of its contents. This report describes the contents of the Chesapeake Bay portion of CBI data bank., See also Volume 1, AD-761 183.

The industrial waste activities at McChord AFB, Washington presently discharge wastewater to Clover Creek and to ground water with little or no treatment. An industrial waste and stream sampling survey was conducted at McChord AFB to determine the magnitude of the pollution problems and to recommend abatement measures. It was determined that the quality of water in Clover Creek was impaired by discharges of floating oils, solvents and fuels from the industrial waste sources and ramp activities. To abate pollution from McChord AFB, recommendations have been made for each industrial waste source--mainly discharge to the sanitary sewer system after oil separation. (Author)

The industrial waste activities at McGuire AFB, New Jersey presently discharge waste water to South Run with little or no treatment. An industrial waste and stream sampling survey was conducted at McGuire AFB to determine the magnitude of the pollution problems and to recommend abatement measures. It was determined that the quality of water in South Run was impaired by Fort Dix partially treated domestic sewage and McGuire AFB industrial waste discharges. Fort Dix plans to construct additional waste treatment facilities. To abate pollution from McGuire AFB, recommendations have been made in this report for each waste source--mainly discharge to the sanitary sewer system after oil separation. If these recommendations are carried out, the quality of water in South Run should be greatly improved. (Author)

Fillers, e.g. mica, MoS2, and graphite (2 to 15%) increased the oxidation stability of greases independently of the basic oil composition or the thickener. The stability of the greases increased with increasing filler content. The fillers adsorbed the polar molecules of the oil and dissolved O2 and oxidation initiators. (Author), Edited trans. of Neftepererabotka i Neftekhimiya (USSR) n3 p27-29 1971, by Marilyn Olaechea.

Multi-attribute scaling procedures were applied to a non-laboratory problem--to the measurement of water quality. Several different variables (such as nitrate, fecal coloforms, turbidity and dissolved solids) contribute to water pollution. It is possible to obtain physical measures of each of the variables, but no physical model exists for combining the measures into an overall index of quality. The multi-attribute scaling procedures were applied to this task by assessing, from water quality engineers, judgments about which variables should be included in the index, the type for combining the variables, the relative importance weights of the different variables, and a curve describing the functional relation between water quality and each variable. Water quality indices were obtained for two specific purposes--for 'public water supply' and for 'fish and wild-life'. The experimenter used a modified Delphi procedure for obtaining concensus among the engineers for each of the indices. (Author)

The report describes results of studies conducted to obtain data to assess the effects of waste disposal on the marine environment of the New York Bight. It concerns hydrographic studies, including surface and bottom water circulation and temporal changes in the area as inferred from density patterns, surface and bottom drifters, direct current measurements, and by analysis of physical characteristics of the water masses. (Author), See also Section 5, AD-739 535 and Section 7, AD-739 537.

A summary is given of some of the available information on the effects of trace additives and impurities on the properties of high water . The properties of water considered, pH and conductivity, are those normally measured in nuclear power plants. The examples of trace chemicals given here are similarly limited to those encountered in nuclear plant water systems. (Author)