Retrieval of water vapor column abundance and aerosol properties from ChemCam passive sky spectroscopy

DOE PAGES

McConnochie, Timothy H.; Smith, Michael D.; Wolff, Michael J.; ...

2017-11-03

In this work, we derive water vapor column abundances and aerosol properties from Mars Science Laboratory (MSL) ChemCam passive mode observations of scattered sky light. This paper covers the methodology and initial results for water vapor and also provides preliminary results for aerosols. The data set presented here includes the results of 113 observations spanning from Mars Year 31 L s = 291° (March 30, 2013) to Mars Year 33 L s= 127° (March 24, 2016). Each ChemCam passive sky observation acquires spectra at two different elevation angles. We fit these spectra with a discrete-ordinates multiple scattering radiative transfer model,more » using the correlated-k approximation for gas absorption bands. The retrieval proceeds by first fitting the continuum of the ratio of the two elevation angles to solve for aerosol properties, and then fitting the continuum-removed ratio to solve for gas abundances. The final step of the retrieval makes use of the observed CO 2 absorptions and the known CO 2 abundance to correct the retrieved water vapor abundance for the effects of the vertical distribution of scattering aerosols and to derive an aerosol scale height parameter. Our water vapor results give water vapor column abundance with a precision of ±0.6 precipitable microns and systematic errors no larger than ±0.3 precipitable microns, assuming uniform vertical mixing. The ChemCam-retrieved water abundances show, with only a few exceptions, the same seasonal behavior and the same timing of seasonal minima and maxima as the TES, CRISM, and REMS-H data sets that we compare them to. However ChemCam-retrieved water abundances are generally lower than zonal and regional scale from-orbit water vapor data, while at the same time being significantly larger than pre-dawn REMS-H abundances. Pending further analysis of REMS-H volume mixing ratio uncertainties, the differences between ChemCam and REMS-H pre-dawn mixing ratios appear to be much too large to be explained by large

Retrieval of water vapor column abundance and aerosol properties from ChemCam passive sky spectroscopy

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

McConnochie, Timothy H.; Smith, Michael D.; Wolff, Michael J.

In this work, we derive water vapor column abundances and aerosol properties from Mars Science Laboratory (MSL) ChemCam passive mode observations of scattered sky light. This paper covers the methodology and initial results for water vapor and also provides preliminary results for aerosols. The data set presented here includes the results of 113 observations spanning from Mars Year 31 L s = 291° (March 30, 2013) to Mars Year 33 L s= 127° (March 24, 2016). Each ChemCam passive sky observation acquires spectra at two different elevation angles. We fit these spectra with a discrete-ordinates multiple scattering radiative transfer model,more » using the correlated-k approximation for gas absorption bands. The retrieval proceeds by first fitting the continuum of the ratio of the two elevation angles to solve for aerosol properties, and then fitting the continuum-removed ratio to solve for gas abundances. The final step of the retrieval makes use of the observed CO 2 absorptions and the known CO 2 abundance to correct the retrieved water vapor abundance for the effects of the vertical distribution of scattering aerosols and to derive an aerosol scale height parameter. Our water vapor results give water vapor column abundance with a precision of ±0.6 precipitable microns and systematic errors no larger than ±0.3 precipitable microns, assuming uniform vertical mixing. The ChemCam-retrieved water abundances show, with only a few exceptions, the same seasonal behavior and the same timing of seasonal minima and maxima as the TES, CRISM, and REMS-H data sets that we compare them to. However ChemCam-retrieved water abundances are generally lower than zonal and regional scale from-orbit water vapor data, while at the same time being significantly larger than pre-dawn REMS-H abundances. Pending further analysis of REMS-H volume mixing ratio uncertainties, the differences between ChemCam and REMS-H pre-dawn mixing ratios appear to be much too large to be explained by large

Measuring the expressed abundance of the three phases of water with an imaging spectrometer over melting snow

NASA Astrophysics Data System (ADS)

Green, Robert O.; Painter, Thomas H.; Roberts, Dar A.; Dozier, Jeff

2006-10-01

From imaging spectrometer data, we simultaneously estimate the abundance of the three phases of water in an environment that includes melting snow, basing the analysis on the spectral shift in the absorption coefficient between water vapor, liquid water, and ice at 940, 980, and 1030 nm respectively. We apply a spectral fitting algorithm that measures the expressed abundance of the three phases of water to a data set acquired by the Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) over Mount Rainier, Washington, on 14 June 1996. Precipitable water vapor varies from 1 mm over the summit of Mount Rainier to 10 mm over the lower valleys to the northwest. Equivalent path absorption of liquid water varies from 0 to 13 mm, with the zero values over rocky areas and high-elevation snow and the high values associated with liquid water held in vegetation canopies and in melting snow. Ice abundance varies from 0 to 30 mm equivalent path absorption in the snow- and glacier-covered portions of Mount Rainier. The water and ice abundances are related to the amount of liquid water and the sizes of the ice grains in the near-surface layer. Precision of the estimates, calculated over locally homogeneous areas, indicates an uncertainty of better than 1.5% for all three phases, except for liquid water in vegetation, where an optimally homogeneous site was not found. The analysis supports new strategies for hydrological research and applications as imaging spectrometers become more available.

Synopsis of ground-water and surface-water resources of North Dakota

USGS Publications Warehouse

Winter, T.C.; Benson, R.D.; Engberg, R.A.; Wiche, G.J.; Emerson, D.G.; Crosby, O.A.; Miller, J.E.

1984-01-01

This report describes the surface- and ground-water resources of North Dakota and the limitations of our understanding of these resources. Ground water and surface water are actually one resource, because they are often hydraulically interconnected. They are discussed separately for convenience. In general, the surface-water resources of the mainstem of the Missouri river are abundant and suitable for most uses. Other rivers may be important locally as water-supply sources, but the quantities of flow are small, quite variable in time, and generally of an unsuitable quality for most uses. Streamflow characteristics of North Dakota reflect its arid to semiarid climate (annual precipitation varies from 13 to 20 inches from west to east across the State), cold winters (usually including a significant snowpack available for spring snowmelt runoff), and the seasonal distribution of annual precipitation (almost 50 percent falls from Nky to July).Significant volumes of shallow ground water, of variable quality are found in the glacial-drift aquifers in parts of central, northern, and eastern North Dakota. Existing information provides only a limited capability to assess the long-term reliability of these scattered aquifers. There are significant indications, however, of water-quality problems related to sustained production of wells if long-term utilization of these aquifers is planned. A summary of the general suitability for use of surface water and ground water is given in Table E1.

Chlorine Abundances in Martian Meteorites

NASA Technical Reports Server (NTRS)

Bogard, D.D.; Garrison, D.H.; Park, J.

2009-01-01

Chlorine measurements made in martian surface rocks by robotic spacecraft typically give Chlorine (Cl) abundances of approximately 0.1-0.8%. In contrast, Cl abundances in martian meteorites appear lower, although data is limited, and martian nakhlites were also subjected to Cl contamination by Mars surface brines. Chlorine abundances reported by one lab for whole rock (WR) samples of Shergotty, ALH77005, and EET79001 range 108-14 ppm, whereas Cl in nakhlites range 73-1900 ppm. Measurements of Cl in various martian weathering phases of nakhlites varied 0.04-4.7% and reveal significant concentration of Cl by martian brines Martian meteorites contain much lower Chlorine than those measured in martian surface rocks and give further confirmation that Cl in these surface rocks was introduced by brines and weathering. It has been argued that Cl is twice as effective as water in lowering the melting point and promoting melting at shallower martian depths, and that significant Cl in the shergottite source region would negate any need for significant water. However, this conclusion was based on experiments that utilized Cl concentrations more analogous to martian surface rocks than to shergottite meteorites, and may not be applicable to shergottites.

Copepod communities from surface and ground waters in the everglades, south Florida

USGS Publications Warehouse

Bruno, M.C.; Cunningham, K.J.; Perry, S.A.

2003-01-01

We studied species composition and individual abundance of copepods in the surficial aquifer northeast of Everglades National Park. We identified the spatial distribution of subsurface habitats by assessing the depth of the high porosity layers in the limestone along a canal system, and we used copepods to assess the exchange between surface water and ground water along canal banks, at levels in the wells where high porosity connections to the canals exist. Surface- and ground-water taxa were defined, and species composition was related to areal position, sampling depth, and time. Subsurface copepod communities were dominated by surface copepods that disperse into the aquifer following the groundwater seepage along canal L-31N. The similarities in species composition between wells along canal reaches, suggest that copepods mainly enter ground water horizontally along canals via active and passive dispersal. Thus, the copepod populations indicate continuous connections between surface- and ground waters. The most abundant species were Orthocyclops modestus, Arctodiaptomus floridanus, Mesocyclops edax, and Thermocyclops parvus, all known in literature from surface habitats; however, these species have been collected in ground water in ENP. Only two stygophiles were collected: Diacylcops nearcticus and Diacyclops crassicaudis brachycercus. Restoration of the Everglades ecosystem requires a mosaic of data to reveal a complete picture of this complex system. The use of copepods as indicators of seepage could be a tool in helping to assess the direction and the duration of surface and ground water exchange.

Monitoring waterbird abundance in wetlands: The importance of controlling results for variation in water depth

USGS Publications Warehouse

Bolduc, F.; Afton, A.D.

2008-01-01

Wetland use by waterbirds is highly dependent on water depth, and depth requirements generally vary among species. Furthermore, water depth within wetlands often varies greatly over time due to unpredictable hydrological events, making comparisons of waterbird abundance among wetlands difficult as effects of habitat variables and water depth are confounded. Species-specific relationships between bird abundance and water depth necessarily are non-linear; thus, we developed a methodology to correct waterbird abundance for variation in water depth, based on the non-parametric regression of these two variables. Accordingly, we used the difference between observed and predicted abundances from non-parametric regression (analogous to parametric residuals) as an estimate of bird abundance at equivalent water depths. We scaled this difference to levels of observed and predicted abundances using the formula: ((observed - predicted abundance)/(observed + predicted abundance)) ?? 100. This estimate also corresponds to the observed:predicted abundance ratio, which allows easy interpretation of results. We illustrated this methodology using two hypothetical species that differed in water depth and wetland preferences. Comparisons of wetlands, using both observed and relative corrected abundances, indicated that relative corrected abundance adequately separates the effect of water depth from the effect of wetlands. ?? 2008 Elsevier B.V.

Associations between water physicochemistry and Prymnesium parvum presence, abundance, and toxicity in west Texas reservoirs

USGS Publications Warehouse

VanLandeghem, Matthew M.; Farooqi, Mukhtar; Southard, Greg M.; Patino, Reynaldo

2015-01-01

Toxic blooms of golden alga (Prymnesium parvum) have caused substantial ecological and economic harm in freshwater and marine systems throughout the world. In North America, toxic blooms have impacted freshwater systems including large reservoirs. Management of water chemistry is one proposed option for golden alga control in these systems. The main objective of this study was to assess physicochemical characteristics of water that influence golden alga presence, abundance, and toxicity in the Upper Colorado River basin (UCR) in Texas. The UCR contains reservoirs that have experienced repeated blooms and other reservoirs where golden alga is present but has not been toxic. We quantified golden alga abundance (hemocytometer counts), ichthyotoxicity (bioassay), and water chemistry (surface grab samples) at three impacted reservoirs on the Colorado River; two reference reservoirs on the Concho River; and three sites at the confluence of these rivers. Sampling occurred monthly from January 2010 to July 2011. Impacted sites were characterized by higher specific conductance, calcium and magnesium hardness, and fluoride than reference and confluence sites. At impacted sites, golden alga abundance and toxicity were positively associated with salinity-related variables and blooms peaked at ~10°C and generally did not occur above 20°C. Overall, these findings suggest management of land and water use to reduce hardness or salinity could produce unfavorable conditions for golden alga.

Bacterial community diversity and variation in spray water sources and the tomato fruit surface.

PubMed

Telias, Adriana; White, James R; Pahl, Donna M; Ottesen, Andrea R; Walsh, Christopher S

2011-04-21

Tomato (Solanum lycopersicum) consumption has been one of the most common causes of produce-associated salmonellosis in the United States. Contamination may originate from animal waste, insects, soil or water. Current guidelines for fresh tomato production recommend the use of potable water for applications coming in direct contact with the fruit, but due to high demand, water from other sources is frequently used. We sought to describe the overall bacterial diversity on the surface of tomato fruit and the effect of two different water sources (ground and surface water) when used for direct crop applications by generating a 454-pyrosequencing 16S rRNA dataset of these different environments. This study represents the first in depth characterization of bacterial communities in the tomato fruit surface and the water sources commonly used in commercial vegetable production. The two water sources tested had a significantly different bacterial composition. Proteobacteria was predominant in groundwater samples, whereas in the significantly more diverse surface water, abundant phyla also included Firmicutes, Actinobacteria and Verrucomicrobia. The fruit surface bacterial communities on tomatoes sprayed with both water sources could not be differentiated using various statistical methods. Both fruit surface environments had a high representation of Gammaproteobacteria, and within this class the genera Pantoea and Enterobacter were the most abundant. Despite the major differences observed in the bacterial composition of ground and surface water, the season long use of these very different water sources did not have a significant impact on the bacterial composition of the tomato fruit surface. This study has provided the first next-generation sequencing database describing the bacterial communities living in the fruit surface of a tomato crop under two different spray water regimes, and therefore represents an important step forward towards the development of science

Bacterial community diversity and variation in spray water sources and the tomato fruit surface

PubMed Central

2011-01-01

Background Tomato (Solanum lycopersicum) consumption has been one of the most common causes of produce-associated salmonellosis in the United States. Contamination may originate from animal waste, insects, soil or water. Current guidelines for fresh tomato production recommend the use of potable water for applications coming in direct contact with the fruit, but due to high demand, water from other sources is frequently used. We sought to describe the overall bacterial diversity on the surface of tomato fruit and the effect of two different water sources (ground and surface water) when used for direct crop applications by generating a 454-pyrosequencing 16S rRNA dataset of these different environments. This study represents the first in depth characterization of bacterial communities in the tomato fruit surface and the water sources commonly used in commercial vegetable production. Results The two water sources tested had a significantly different bacterial composition. Proteobacteria was predominant in groundwater samples, whereas in the significantly more diverse surface water, abundant phyla also included Firmicutes, Actinobacteria and Verrucomicrobia. The fruit surface bacterial communities on tomatoes sprayed with both water sources could not be differentiated using various statistical methods. Both fruit surface environments had a high representation of Gammaproteobacteria, and within this class the genera Pantoea and Enterobacter were the most abundant. Conclusions Despite the major differences observed in the bacterial composition of ground and surface water, the season long use of these very different water sources did not have a significant impact on the bacterial composition of the tomato fruit surface. This study has provided the first next-generation sequencing database describing the bacterial communities living in the fruit surface of a tomato crop under two different spray water regimes, and therefore represents an important step forward towards the

Preliminary Martian Atmospheric Water Vapour Column Abundances with Mars Climate Sounder

NASA Astrophysics Data System (ADS)

Lolachi, Ramin; Irwin, P. G. J.; Teanby, N.; Calcutt, S.; Howett, C. J. A.; Bowles, N. E.; Taylor, F. W.; Schofield, J. T.; Kleinboehl, A.; McCleese, D. J.

2007-12-01

Mars Climate Sounder (MCS) is an infra-red radiometer on board NASA's Mars Reconnaissance Orbiter (MRO) launched in August 2005 and now orbiting Mars in a near circular polar orbit. MCS has nine spectral channels in the range 0.3-50 µm. Goals of MCS include global characterization of atmospheric temperature, dust and water profiles observing temporal and spatial variation. Using Oxford University's multivariate retrieval algorithm, NEMESIS, we present preliminary determinations of the water vapour column abundance in the Martian atmosphere during the period September-October 2006 (Ls range 111-129°, i.e. northern hemisphere summer). A combination of spectral channels inside and outside the water vapour rotation band (at 50 µm) are used to retrieve the column abundances mainly using nadir observations (as aerosol opacity is less important relative to water vapour opacity in nadir viewing geometry). We then compare these column abundances to earlier results from the Viking Orbiter Mars Atmospheric Water Detectors (MAWD) and the Thermal Emission Spectrometer (TES) on Mars Global Surveyor.

Seasonal abundance and vertical distribution of capelin (Mallotus villosus) in relation to water temperature at a coastal site off eastern Newfoundland

USGS Publications Warehouse

Methven, David A.; Piatt, John F.

1991-01-01

The seasonal abundance and vertical distribution of capelin in relation to water temperature have been investigated by conducting repeated hydroacoustic surveys at a coastal site off eastern Newfoundland. Water temperatures were warmer in 1983 than in 1984 as indicated by the earlier appearance and greater depth of the seasonal thermocline. Correspondingly, schools of capelin appeared earlier, were more abundant, and extended deeper in the water column in 1983 than in 1984. Most capelin were found between the surface and the 5°C isotherm. In both years, initial peaks of capelin abundance occurred when nearshore water temperatures increased from about 0-1°C to above 6°C and, at or near, periods of maximum tidal oscillation. Short-term variations in the depth of the 5°C isotherm were related to nearshore wind-induced upwelling events. Annual variations corresponded to the volume of cold (>0°C) water and sea-ice transported south by the Labrador Current.

Natural Sunlight Shapes Crude Oil-Degrading Bacterial Communities in Northern Gulf of Mexico Surface Waters

PubMed Central

Bacosa, Hernando P.; Liu, Zhanfei; Erdner, Deana L.

2015-01-01

Following the Deepwater Horizon (DWH) spill in 2010, an enormous amount of oil was observed in the deep and surface waters of the northern Gulf of Mexico. Surface waters are characterized by intense sunlight and high temperature during summer. While the oil-degrading bacterial communities in the deep-sea plume have been widely investigated, the effect of natural sunlight on those in oil polluted surface waters remains unexplored to date. In this study, we incubated surface water from the DWH site with amendments of crude oil, Corexit dispersant, or both for 36 days under natural sunlight in the northern Gulf of Mexico. The bacterial community was analyzed over time for total abundance, density of alkane and polycyclic aromatic hydrocarbon degraders, and community composition via pyrosequencing. Our results showed that, for treatments with oil and/or Corexit, sunlight significantly reduced bacterial diversity and evenness and was a key driver of shifts in bacterial community structure. In samples containing oil or dispersant, sunlight greatly reduced abundance of the Cyanobacterium Synechococcus but increased the relative abundances of Alteromonas, Marinobacter, Labrenzia, Sandarakinotalea, Bartonella, and Halomonas. Dark samples with oil were represented by members of Thalassobius, Winogradskyella, Alcanivorax, Formosa, Pseudomonas, Eubacterium, Erythrobacter, Natronocella, and Coxiella. Both oil and Corexit inhibited the Candidatus Pelagibacter with or without sunlight exposure. For the first time, we demonstrated the effects of light in structuring microbial communities in water with oil and/or Corexit. Overall, our findings improve understanding of oil pollution in surface water, and provide unequivocal evidence that sunlight is a key factor in determining bacterial community composition and dynamics in oil polluted marine waters. PMID:26648916

Natural Sunlight Shapes Crude Oil-Degrading Bacterial Communities in Northern Gulf of Mexico Surface Waters.

PubMed

Bacosa, Hernando P; Liu, Zhanfei; Erdner, Deana L

2015-01-01

Following the Deepwater Horizon (DWH) spill in 2010, an enormous amount of oil was observed in the deep and surface waters of the northern Gulf of Mexico. Surface waters are characterized by intense sunlight and high temperature during summer. While the oil-degrading bacterial communities in the deep-sea plume have been widely investigated, the effect of natural sunlight on those in oil polluted surface waters remains unexplored to date. In this study, we incubated surface water from the DWH site with amendments of crude oil, Corexit dispersant, or both for 36 days under natural sunlight in the northern Gulf of Mexico. The bacterial community was analyzed over time for total abundance, density of alkane and polycyclic aromatic hydrocarbon degraders, and community composition via pyrosequencing. Our results showed that, for treatments with oil and/or Corexit, sunlight significantly reduced bacterial diversity and evenness and was a key driver of shifts in bacterial community structure. In samples containing oil or dispersant, sunlight greatly reduced abundance of the Cyanobacterium Synechococcus but increased the relative abundances of Alteromonas, Marinobacter, Labrenzia, Sandarakinotalea, Bartonella, and Halomonas. Dark samples with oil were represented by members of Thalassobius, Winogradskyella, Alcanivorax, Formosa, Pseudomonas, Eubacterium, Erythrobacter, Natronocella, and Coxiella. Both oil and Corexit inhibited the Candidatus Pelagibacter with or without sunlight exposure. For the first time, we demonstrated the effects of light in structuring microbial communities in water with oil and/or Corexit. Overall, our findings improve understanding of oil pollution in surface water, and provide unequivocal evidence that sunlight is a key factor in determining bacterial community composition and dynamics in oil polluted marine waters.

Water abundance and accretion history of terrestrial planets

NASA Technical Reports Server (NTRS)

Waenke, H.; Dreibus, G.

1994-01-01

According to a widespread believe, Earth's water was either added in form of a late volatile-rich veneer or as we have argued repeatedly that of all the water which was added to the Earth only that portion remained which was added towards the end of accretion when the mean oxygen fugacity of the accreting material became so high that metallic iron could not exist any longer. Prior to this moment, all the water in the latter scenario would have been used up for the oxidation of iron. Fe + H2O yields FeO + H2. Huge quantities of hydrogen would continuously be produced in this scenario which escaped. In the same moment the hydrogen on its way to the surface would lead to an efficient degassing of the growing Earth's mantle. The fact that - assuming C1 abundances - the amount of iridium in the Earth's mantle agrees, within a factor of two with the total water inventory of the Earth's mantle and crust is taken as evidence for the validity of such a scenario. In both scenarios, the Earth's mantle would remain dry and devoid of other volatiles. Some species soluble in metallic iron like carbon and hydrogen will probably partly enter the core in some portions. It is generally assumed that today a considerable portion of the earth's total water inventory resides in the mantle. It is also clear that over the history of the Earth the water of the Earth's oceans has been recycled many times through the mantle. This is the consequence of plate subduction. In a similar way mantle convection was probably responsible to being water into the originally dry mantle. As a consequence, today the Earth is wet both inside and outside.

Geographic patterns of fishes and jellyfish in Puget Sound surface waters

USGS Publications Warehouse

Rice, Casimir A.; Duda, Jeffrey J.; Greene, Correigh M.; Karr, James R.

2012-01-01

We explored patterns of small pelagic fish assemblages and biomass of gelatinous zooplankton (jellyfish) in surface waters across four oceanographic subbasins of greater Puget Sound. Our study is the first to collect data documenting biomass of small pelagic fishes and jellyfish throughout Puget Sound; sampling was conducted opportunistically as part of a juvenile salmon survey of daytime monthly surface trawls at 52 sites during May–August 2003. Biomass composition differed spatially and temporally, but spatial differences were more distinct. Fish dominated in the two northern basins of Puget Sound, whereas jellyfish dominated in the two southern basins. Absolute and relative abundance of jellyfish, hatchery Chinook salmon Oncorhynchus tshawytscha, and chum salmon O. keta decreased with increasing latitude, whereas the absolute and relative abundance of most fish species and the average fish species richness increased with latitude. The abiotic factors with the strongest relationship to biomass composition were latitude, water clarity, and sampling date. Further study is needed to understand the spatial and temporal heterogeneity in the taxonomic composition we observed in Puget Sound surface waters, especially as they relate to natural and anthropogenic influences.

viral abundance distribution in deep waters of the Northern of South China Sea

NASA Astrophysics Data System (ADS)

He, Lei; Yin, Kedong

2017-04-01

Little is known about the vertical distribution and interaction of viruses and bacteria in the deep ocean water column. The vertical distribution of viral-like particles and bacterial abundance was investigated in the deep water column in the South China Sea during September 2005 along with salinity, temperature and dissolved oxygen. There were double maxima in the ratio of viral to bacterial abundance (VBR) in the water column: the subsurface maximum located at 50-100 m near the pycnocline layer, and the deep maximum at 800-1000 m. At the subsurface maximum of VBR, both viral and bacterial abundance were maximal in the water column, and at the deep maximum of VBR, both viral and bacterial abundance were low, but bacterial abundance was relatively lower than viral abundance. The subsurface VBR maximum coincided with the subsurface chlorophyll maximum while the deep VBR maximum coincided with the minimum in dissolved oxygen (2.91mg L-1). Therefore, we hypothesize that the two maxima were formed by different mechanisms. The subsurface VBR maximum was formed due to an increase in bacterial abundance resulting from the stimulation of abundant organic supply at the subsurface chlorophyll maximum, whereas the deep VBR maximum was formed due to a decrease in bacterial abundance caused by more limitation of organic matter at the oxygen minimum. The evidence suggests that viruses play an important role in controlling bacterial abundance in the deep water column due to the limitation of organic matter supply. In turn, this slows down the formation of the oxygen minimum in which oxygen may be otherwise lower. The mechanism has a great implication that viruses could control bacterial decomposition of organic matter, oxygen consumption and nutrient remineralization in the deep oceans.

Temporal variations in the abundance and composition of biofilm communities colonizing drinking water distribution pipes.

PubMed

Kelly, John J; Minalt, Nicole; Culotti, Alessandro; Pryor, Marsha; Packman, Aaron

2014-01-01

Pipes that transport drinking water through municipal drinking water distribution systems (DWDS) are challenging habitats for microorganisms. Distribution networks are dark, oligotrophic and contain disinfectants; yet microbes frequently form biofilms attached to interior surfaces of DWDS pipes. Relatively little is known about the species composition and ecology of these biofilms due to challenges associated with sample acquisition from actual DWDS. We report the analysis of biofilms from five pipe samples collected from the same region of a DWDS in Florida, USA, over an 18 month period between February 2011 and August 2012. The bacterial abundance and composition of biofilm communities within the pipes were analyzed by heterotrophic plate counts and tag pyrosequencing of 16S rRNA genes, respectively. Bacterial numbers varied significantly based on sampling date and were positively correlated with water temperature and the concentration of nitrate. However, there was no significant relationship between the concentration of disinfectant in the drinking water (monochloramine) and the abundance of bacteria within the biofilms. Pyrosequencing analysis identified a total of 677 operational taxonomic units (OTUs) (3% distance) within the biofilms but indicated that community diversity was low and varied between sampling dates. Biofilms were dominated by a few taxa, specifically Methylomonas, Acinetobacter, Mycobacterium, and Xanthomonadaceae, and the dominant taxa within the biofilms varied dramatically between sampling times. The drinking water characteristics most strongly correlated with bacterial community composition were concentrations of nitrate, ammonium, total chlorine and monochloramine, as well as alkalinity and hardness. Biofilms from the sampling date with the highest nitrate concentration were the most abundant and diverse and were dominated by Acinetobacter.

Seagrass distribution and abundance in Eastern Gulf of Mexico coastal waters

NASA Astrophysics Data System (ADS)

Iverson, Richard L.; Bittaker, Henry F.

1986-05-01

The marine angiosperms Thalassia testudinum, Syringodium filiforme, and Halodule wrightii form two of the largest reported seagrass beds along the northwest and southern coasts of Florida where they cover about 3000 square km in the Big Bend area and about 5500 square km in Florida Bay, respectively. Most of the leaf biomass in the Big Bend area and outer Florida Bay was composed of Thalassia testudinum and Syringodium filiforme which were distributed throughout the beds but which were more abundant in shallow depths. A short-leaved form of Halodule wrightii grew in monotypic stands in shallow water near the inner edges of the beds, while Halophila decipiens and a longer-leaved variety of H. wrightii grew scattered throughout the beds, in monotypic stands near the outer edges of the beds, and in deeper water outside the beds. Halophila engelmanni was observed scattered at various depths throughout the seagrass beds and in monospecific patches in deep water outside the northern bed. Ruppia maritima grew primarily in brackish water around river mouths. The cross-shelf limits of the two major seagrass beds are controlled nearshore by increased water turbidity and lower salinity around river mouths and off-shore by light penetration to depths which receive 10% or more of sea surface photosynthetically active radiation. Seagrasses form large beds only along low energy reaches of the coast. The Florida Bay seagrass bed contained about twice the short-shoot density of both Thalassia testudinum and Syringodium filiforme, for data averaged over all depths, and about four times the average short-shoot density of both species in shallow water compared with the Big Bend seagrass bed. The differences in average seagrass abundance between Florida Bay and the Big Bend area may be a consequence of the effects of greater seasonal solar radiation and water temperature fluctuations experienced by plants in the northern bed, which lies at the northern distribution limit for American

Water in Massive protostellar objects: first detection of THz water maser and water inner abundance.

NASA Astrophysics Data System (ADS)

Herpin, Fabrice

2014-10-01

The formation massive stars is still not well understood. Despite numerous water line observations with Herschel telescope, over a broad range of energies, in most of the observed sources the WISH-KP (Water In Star-forming regions with Herschel, Co-PI: F. Herpin) observations were not able to trace the emission from the hot core. Moreover, water maser model predict that several THz water maser should be detectable in these objects. We aim to detect for the first time the THz maser lines o-H2O 8(2,7)- 7(3,4) at 1296.41106 GHz and p-H2O 7(2,6)- 6(3,3) at 1440.78167 GHz as predicted by the model. We propose two sources for a northern flight as first priority and two other sources for a possible southern flight. This will 1) constrain the maser theory, 2) constrain the physical conditions and water abundance in the inner layers of the prostellar environnement. In addition, we will use the p-H2O 3(3,1)- 4(0,4) thermal line at 1893.68651 GHz (L2 channel) in order to probe the physical conditions and water abundance in the inner layers of the prostellar objects where HIFI-Herschel has partially failed.

Characterization of dissolved organic matter for prediction of trihalomethane formation potential in surface and sub-surface waters.

PubMed

Awad, John; van Leeuwen, John; Chow, Christopher; Drikas, Mary; Smernik, Ronald J; Chittleborough, David J; Bestland, Erick

2016-05-05

Dissolved organic matter (DOM) in surface waters used for drinking purposes can vary markedly in character dependent on their sources within catchments. The character of DOM further influences the formation of disinfection by products when precursor DOM present in drinking water reacts with chlorine during disinfection. Here we report the development of models that describe the formation potential of trihalomethanes (THMFP) dependent on the character of DOM in waters from discrete catchments with specific land-use and soil textures. DOM was characterized based on UV absorbance at 254 nm, apparent molecular weight and relative abundances of protein-like and humic-like compounds. DOM character and Br concentration (up to 0.5 mg/L) were used as variables in models (R(2)>0.93) of THMFP, which ranged from 19 to 649 μg/L. Chloroform concentration (12-594 μg/L) and relative abundance (27-99%) were first modeled (R(2)>0.85) and from these, the abundances of bromodichloromethane and chlorodibromomethane estimated using power and exponential functions, respectively (R(2)>0.98). From these, the abundance of bromoform is calculated. The proposed model may be used in risk assessment of catchment factors on formation of trihalomethanes in drinking water, in context of treatment efficiency for removal of organic matter. Crown Copyright © 2016. Published by Elsevier B.V. All rights reserved.

Effects of effluent water on the abundance of cowpea insect pests.

PubMed

Tiroesele, Bamphitlhi; Sitwane, Monametsi; Obopile, M; Ullah, Muhammad Irfan; Ali, Sajjad

2017-10-03

Botswana experiences low and unreliable rainfall. Thus, the use of effluent water in agriculture is increasingly important. Insect damage is the major constraint for cowpea grain production in the most cowpea-producing lands. We investigated the effects of effluent water on insect pest abundance on cowpea (Vigna unguiculata) under field conditions. The experiment was laid out in a randomized complete block design with 100, 75, 50, and 25% of effluent water and 0% (control-clean tap water) treatments. Treatments with 100% effluent water resulted in a significant increase in insect pest populations as compared with the control. These results show that the use of effluent water to irrigate crops may increase incidence, abundance, and damage caused by insect pests possibly by decreasing plant vigor. The use of effluent water in agriculture should be addressed in a wise way.

Surface abundances of ON stars

NASA Astrophysics Data System (ADS)

Martins, F.; Simón-Díaz, S.; Palacios, A.; Howarth, I.; Georgy, C.; Walborn, N. R.; Bouret, J.-C.; Barbá, R.

2015-06-01

Context. Massive stars burn hydrogen through the CNO cycle during most of their evolution. When mixing is efficient or when mass transfer in binary systems occurs, chemically processed material is observed at the surface of O and B stars. Aims: ON stars show stronger lines of nitrogen than morphologically normal counterparts. Whether this corresponds to the presence of material processed through the CNO cycle is not known. Our goal is to answer this question. Methods: We performed a spectroscopic analysis of a sample of ON stars with atmosphere models. We determined the fundamental parameters as well as the He, C, N, and O surface abundances. We also measured the projected rotational velocities. We compared the properties of the ON stars to those of normal O stars. Results: We show that ON stars are usually rich in helium. Their CNO surface abundances are fully consistent with predictions of nucleosynthesis. ON stars are more chemically evolved and rotate - on average - faster than normal O stars. Evolutionary models including rotation cannot account for the extreme enrichment observed among ON main sequence stars. Some ON stars are members of binary systems, but others are single stars as indicated by stable radial velocities. Mass transfer is therefore not a simple explanation for the observed chemical properties. Conclusions: We conclude that ON stars show extreme chemical enrichment at their surface, consistent with nucleosynthesis through the CNO cycle. Its origin is not clear at present. Based on observations obtained 1) at the Anglo-Australian Telescope; 2) at the Canada-France-Hawaii Telescope (CFHT), which is operated by the National Research Council (NRC) of Canada, the Institut National des Science de l'Univers of the Centre National de la Recherche Scientifique (CNRS) of France, and the University of Hawaii; 3) at the ESO/La Silla Observatory under programs 081.D-2008, 083.D-0589, 086.D-0997; 4) the Nordic Optical Telescope, operated on the island of La

Temporal Variations in the Abundance and Composition of Biofilm Communities Colonizing Drinking Water Distribution Pipes

PubMed Central

Kelly, John J.; Minalt, Nicole; Culotti, Alessandro; Pryor, Marsha; Packman, Aaron

2014-01-01

Pipes that transport drinking water through municipal drinking water distribution systems (DWDS) are challenging habitats for microorganisms. Distribution networks are dark, oligotrophic and contain disinfectants; yet microbes frequently form biofilms attached to interior surfaces of DWDS pipes. Relatively little is known about the species composition and ecology of these biofilms due to challenges associated with sample acquisition from actual DWDS. We report the analysis of biofilms from five pipe samples collected from the same region of a DWDS in Florida, USA, over an 18 month period between February 2011 and August 2012. The bacterial abundance and composition of biofilm communities within the pipes were analyzed by heterotrophic plate counts and tag pyrosequencing of 16S rRNA genes, respectively. Bacterial numbers varied significantly based on sampling date and were positively correlated with water temperature and the concentration of nitrate. However, there was no significant relationship between the concentration of disinfectant in the drinking water (monochloramine) and the abundance of bacteria within the biofilms. Pyrosequencing analysis identified a total of 677 operational taxonomic units (OTUs) (3% distance) within the biofilms but indicated that community diversity was low and varied between sampling dates. Biofilms were dominated by a few taxa, specifically Methylomonas, Acinetobacter, Mycobacterium, and Xanthomonadaceae, and the dominant taxa within the biofilms varied dramatically between sampling times. The drinking water characteristics most strongly correlated with bacterial community composition were concentrations of nitrate, ammonium, total chlorine and monochloramine, as well as alkalinity and hardness. Biofilms from the sampling date with the highest nitrate concentration were the most abundant and diverse and were dominated by Acinetobacter. PMID:24858562

Catalysts Based on Earth-Abundant Metals for Visible Light-Driven Water Oxidation Reaction.

PubMed

Lin, Junqi; Han, Qing; Ding, Yong

2018-06-04

Exploration of water oxidation catalyst (WOC) with excellent performance is the key for the overall water splitting reaction, which is a feasible strategy to convert solar energy to chemical energy. Although some compounds composed of noble metals, mainly Ru and Ir, have been reported to catalyze water oxidation with high efficiency, catalysts based on low-cost and earth-abundant transition metals are essential for realizing economical and large-scale light-driven water splitting. Various WOCs containing earth-abundant metals (mainly Mn, Fe, Co, Ni, Cu) have been utilized for visible light-driven water oxidation in recent years. In this Personal Account, we summarize our recent developments in WOCs based on earth-abundant transition metals including polyoxometalates (POMs), metal oxides or bimetal oxides, and metal complexes containing multidentate ligand scaffolds for visible light-driven water oxidation reaction. © 2018 The Chemical Society of Japan & Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Heterogeneous Ice Nucleation: Interplay of Surface Properties and Their Impact on Water Orientations.

PubMed

Glatz, Brittany; Sarupria, Sapna

2018-01-23

Ice is ubiquitous in nature, and heterogeneous ice nucleation is the most common pathway of ice formation. How surface properties affect the propensity to observe ice nucleation on that surface remains an open question. We present results of molecular dynamics studies of heterogeneous ice nucleation on model surfaces. The models surfaces considered emulate the chemistry of kaolinite, an abundant component of mineral dust. We investigate the interplay of surface lattice and hydrogen bonding properties in affecting ice nucleation. We find that lattice matching and hydrogen bonding are necessary but not sufficient conditions for observing ice nucleation at these surfaces. We correlate this behavior to the orientations sampled by the metastable supercooled water in contact with the surfaces. We find that ice is observed in cases where water molecules not only sample orientations favorable for bilayer formation but also do not sample unfavorable orientations. This distribution depends on both surface-water and water-water interactions and can change with subtle modifications to the surface properties. Our results provide insights into the diverse behavior of ice nucleation observed at different surfaces and highlight the complexity in elucidating heterogeneous ice nucleation.

Seasonal lake surface water temperature trends reflected by heterocyst glycolipid-based molecular thermometers

NASA Astrophysics Data System (ADS)

Bauersachs, T.; Rochelmeier, J.; Schwark, L.

2015-06-01

It has been demonstrated that the relative distribution of heterocyst glycolipids (HGs) in cultures of N2-fixing heterocystous cyanobacteria is largely controlled by growth temperature, suggesting a potential use of these components in paleoenvironmental studies. Here, we investigated the effect of environmental parameters (e.g., surface water temperatures, oxygen concentrations and pH) on the distribution of HGs in a natural system using water column filtrates collected from Lake Schreventeich (Kiel, Germany) from late July to the end of October 2013. HPLC-ESI/MS (high-performance liquid chromatography coupled to electrospray ionization-mass spectrometry) analysis revealed a dominance of 1-(O-hexose)-3,25-hexacosanediols (HG26 diols) and 1-(O-hexose)-3-keto-25-hexacosanol (HG26 keto-ol) in the solvent-extracted water column filtrates, which were accompanied by minor abundances of 1-(O-hexose)-3,27-octacosanediol (HG28 diol) and 1-(O-hexose)-3-keto-27-octacosanol (HG28 keto-ol) as well as 1-(O-hexose)-3,25,27-octacosanetriol (HG28 triol) and 1-(O-hexose)-3-keto-25,27-octacosanediol (HG28 keto-diol). Fractional abundances of alcoholic and ketonic HGs generally showed strong linear correlations with surface water temperatures and no or only weak linear correlations with both oxygen concentrations and pH. Changes in the distribution of the most abundant diol and keto-ol (e.g., HG26 diol and HG26 keto-ol) were quantitatively expressed as the HDI26 (heterocyst diol index of 26 carbon atoms) with values of this index ranging from 0.89 in mid-August to 0.66 in mid-October. An average HDI26 value of 0.79, which translates into a calculated surface water temperature of 15.8 ± 0.3 °C, was obtained from surface sediments collected from Lake Schreventeich. This temperature - and temperatures obtained from other HG indices (e.g., HDI28 and HTI28) - is similar to the one measured during maximum cyanobacterial productivity in early to mid-September and suggests that HGs

Exploring the differences of antibiotic resistance genes profiles between river surface water and sediments using metagenomic approach.

PubMed

Jiang, Haoyu; Zhou, Renjun; Zhang, Mengdi; Cheng, Zhineng; Li, Jun; Zhang, Gan; Chen, Baowei; Zou, Shichun; Yang, Ying

2018-05-30

To better understand the potential genic communication and dissemination of antibiotic resistance genes (ARGs) in different environmental matrices, the differences of ARG profiles between river surface water and sediments were explored. Metagenomic analysis was applied to investigate the comprehensive ARG profiles in water and sediment samples collected from the highly human-impacted catchment of the Beijiang River and its river source. A total of 135 ARG subtypes belonging to 18 ARG types were identified. Generally, ARGs in surface water were more diverse and abundant than those in sediments. ARG profiles in the surface water and sediment samples were distinct from each other, but some ARGs were shared by the surface water and sediments. Results revealed that multidrug and bacitracin resistance genes were the predominant ARGs types in both surface water (0.30, 0.17 copies/cell) and sediments (0.19, 0.15 copies/cell). 73 ARG subtypes were shared by the water and sediment samples and had taken over 90% of the total detected ARG abundance. Most of the shared ARGs are resistant to the clinically relevant antibiotics. Furthermore, significant correlations between the ARGs and 21 shared genera or mobile genetic elements (MGEs) (plasmids and integrons) were found in surface water and sediments, suggesting the important role of genera or MGEs in shaping ARGs profiles, propagation and distribution. These findings provide deeper insight into mitigating the propagation of ARGs and the associated risks to public health. Copyright © 2018 Elsevier Inc. All rights reserved.

Developing the greatest Blue Economy: Water productivity, fresh water depletion, and virtual water trade in the Great Lakes basin

NASA Astrophysics Data System (ADS)

Mayer, A. S.; Ruddell, B. L.; Mubako, S. T.

2016-12-01

The Great Lakes basin hosts the world's most abundant surface fresh water reserve. Historically an industrial and natural resource powerhouse, the region has suffered economic stagnation in recent decades. Meanwhile, growing water resource scarcity around the world is creating pressure on water-intensive human activities. This situation creates the potential for the Great Lakes region to sustainably utilize its relative water wealth for economic benefit. We combine economic production and trade datasets with water consumption data and models of surface water depletion in the region. We find that, on average, the current economy does not create significant impacts on surface waters, but there is some risk that unregulated large water uses can create environmental flow impacts if they are developed in the wrong locations. Water uses drawing on deep groundwater or the Great Lakes themselves are unlikely to create a significant depletion, and discharge of groundwater withdrawals to surface waters offsets most surface water depletion. This relative abundance of surface water means that science-based management of large water uses to avoid accidentally creating "hotspots" is likely to be successful in avoiding future impacts, even if water use is significantly increased. Commercial water uses are the most productive, with thermoelectric, mining, and agricultural water uses in the lowest tier of water productivity. Surprisingly for such a water-abundant economy, the region is a net importer of water-derived goods and services. This, combined with the abundance of surface water, suggests that the region's water-based economy has room to grow in the 21st century.

Water organization between oppositely charged surfaces: Implications for protein sliding along DNA a)

NASA Astrophysics Data System (ADS)

Marcovitz, Amir; Naftaly, Aviv; Levy, Yaakov

2015-02-01

Water molecules are abundant in protein-DNA interfaces, especially in their nonspecific complexes. In this study, we investigated the organization and energetics of the interfacial water by simplifying the geometries of the proteins and the DNA to represent them as two equally and oppositely charged planar surfaces immersed in water. We found that the potential of mean force for bringing the two parallel surfaces into close proximity comprises energetic barriers whose properties strongly depend on the charge density of the surfaces. We demonstrated how the organization of the water molecules into discretized layers and the corresponding energetic barriers to dehydration can be modulated by the charge density on the surfaces, salt, and the structure of the surfaces. The 1-2 layers of ordered water are tightly bound to the charged surfaces representing the nonspecific protein-DNA complex. This suggests that water might mediate one-dimensional diffusion of proteins along DNA (sliding) by screening attractive electrostatic interactions between the positively charged molecular surface on the protein and the negatively charged DNA backbone and, in doing so, reduce intermolecular friction in a manner that smoothens the energetic landscape for sliding, and facilitates the 1D diffusion of the protein.

Seasonal Variation in Sea Turtle Density and Abundance in the Southeast Florida Current and Surrounding Waters.

PubMed

Bovery, Caitlin M; Wyneken, Jeanette

2015-01-01

Assessment and management of sea turtle populations is often limited by a lack of available data pertaining to at-sea distributions at appropriate spatial and temporal resolutions. Assessing the spatial and temporal distributions of marine turtles in an open system poses both observational and analytical challenges due to the turtles' highly migratory nature. Surface counts of marine turtles in waters along the southern part of Florida's east coast were made in and adjacent to the southeast portion of the Florida Current using standard aerial surveys during 2011 and 2012 to assess their seasonal presence. This area is of particular concern for sea turtles as interest increases in offshore energy developments, specifically harnessing the power of the Florida Current. While it is understood that marine turtles use these waters, here we evaluate seasonal variation in sea turtle abundance and density over two years. Density of sea turtles observed within the study area ranged from 0.003 turtles km-2 in the winter of 2011 to 0.064 turtles km-2 in the spring of 2012. This assessment of marine turtles in the waters off southeast Florida quantifies their in-water abundance across seasons in this area to establish baselines and inform future management strategies of these protected species.

Weakly bound water structure, bond valence saturation and water dynamics at the goethite (100) surface/aqueous interface: ab initio dynamical simulations

DOE PAGES

Chen, Ying; Bylaska, Eric J.; Weare, John H.

2017-03-31

Many important geochemical and biogeochemical reactions occur in the mineral/formation water interface of the highly abundant mineral, goethite (α-Fe(OOH). Ab-initio molecular dynamics (AIMD) simulations of the goethite α-FeOOH (100) surface and the structure, water bond formation and dynamics of water molecules in the mineral/aqueous interface are presented. Here, several exchange correlation functionals were employed (PBE96, PBE96+Grimme, and PBE0) in the simulations of a (3 x 2) goethite surface with 65 absorbed water molecules in a 3D-periodic supercell (a=30 Å, FeOOH slab ~12 Å thick, solvation layer ~18 Å thick).

Weakly bound water structure, bond valence saturation and water dynamics at the goethite (100) surface/aqueous interface: ab initio dynamical simulations

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

Chen, Ying; Bylaska, Eric J.; Weare, John H.

Many important geochemical and biogeochemical reactions occur in the mineral/formation water interface of the highly abundant mineral, goethite (α-Fe(OOH). Ab-initio molecular dynamics (AIMD) simulations of the goethite α-FeOOH (100) surface and the structure, water bond formation and dynamics of water molecules in the mineral/aqueous interface are presented. Here, several exchange correlation functionals were employed (PBE96, PBE96+Grimme, and PBE0) in the simulations of a (3 x 2) goethite surface with 65 absorbed water molecules in a 3D-periodic supercell (a=30 Å, FeOOH slab ~12 Å thick, solvation layer ~18 Å thick).

Cyanobacteria abundance and its relationship to water quality in the Mid-Cross River floodplain, Nigeria.

PubMed

Okogwu, Okechukwu I; Ugwumba, Alex O

2009-01-01

The physicochemical variables and cyanobacteria of Mid-Cross River, Nigeria, were studied in six stations between March 2005 and August 2006 to determine the relationship between water quality and cyanobacteria abundance. Canonical Correspondence Analysis (CCA) showed that biological oxygen demand (BOD), dissolved oxygen, pH, water velocity, width and depth were important environmental factors that influenced cyanobacteria abundance. Trace metals, phosphate and nitrate increased significantly from values of previous studies indicating increased eutrophication of the river but were weakly correlated with cyanobacteria abundance and could be scarcely regarded as regulating factors. A higher cyanobacteria abundance was recorded during the wet season in most of the sampled stations. The dominant cyanobacteria included Microcystis aeruginosa, Aphanizomenon flos-aquae, Oscillatoria limnetica and Anabaena spiroides. The toxins produced by these species could degrade water quality. The factors favouring cyanobacteria abundance were identified as increased pH, width and depth. Increase in cyanobacteria abundance was associated with reduction in dissolved oxygen and increase in BOD values.

Effect of water irrigation volume on Capsicum frutescens growth and plankton abundance in aquaponics system

NASA Astrophysics Data System (ADS)

Andriani, Y.; Dhahiyat, Y.; Zahidah; Subhan, U.; Iskandar; Zidni, I.; Mawardiani, T.

2018-03-01

This study aimed to understand Capsicum frutescens growth and plankton abundance in aquaponics culture. A Completely Randomized Design (CRD) with six treatments in triplicates comprising of treatment A (positive control using organic liquid fertilizer), B (negative control without fertilizer), C (drip irrigation aquaponics with a water debit of 100 ml/day/plant), D (drip irrigation aquaponics with a water debit of 150 ml/day/plant), E (drip irrigation with a water debit of 200 ml/day/plant), and F (drip irrigation aquaponics with a water debit of 250 ml/day/plant) was applied. The water used in treatments C, D, E, and F contained comet fish feces as fertilizer. C. frutescens growth and plankton abundance were observed. Analysis was conducted using analysis of variance for plant productivity and descriptive analysis for plankton abundance and water quality. The results of this study showed that the highest plant growth was seen in plants receiving F treatment with 50 ml/day drip irrigation. However, no significant difference was found when compared to the positive control with organic artificial fertilizer. Eleven types of phytoplankton and six types of zooplankton were found, with Stanieria sp. as the most abundant phytoplankton and Brachionus sp. and Epistylis sp. as the most abundant zooplanktons.

Bringing abundance into environmental politics: Constructing a Zionist network of water abundance, immigration, and colonization.

PubMed

Alatout, Samer

2009-06-01

For more than five decades, resource scarcity has been the lead story in debates over environmental politics. More importantly, and whenever environmental politics implies conflict, resource scarcity is constructed as the culprit. Abundance of resources, if at all visited in the literature, holds less importance. Resource abundance is seen, at best, as the other side of scarcity--maybe the successful conclusion of multiple interventions that may turn scarcity into abundance. This paper reinstates abundance as a politico-environmental category in its own right. Rather than relegating abundance to a second-order environmental actor that matters only on occasion, this paper foregrounds it as a crucial element in modern environmental politics. On the substantive level, and using insights from science and technology studies, especially a slightly modified actor-network framework, I describe the emergence and consolidation of a Zionist network of abundance, immigration, and colonization in Palestine between 1918 and 1948. The essential argument here is that water abundance was constructed as fact, and became a political rallying point around which a techno-political network emerged that included a great number of elements. To name just a few, the following were enrolled in the service of such a network: geologists, geophysicists, Zionist settlement experts, Zionist organizations, political and technical categories of all sorts, Palestinians as the negated others, Palestinian revolts in search of political rights, the British Mandate authorities, the hydrological system of Palestine, and the absorptive capacity of Palestine, among others. The point was to successfully articulate these disparate elements into a network that seeks opening Palestine for Jewish immigration, redefining Palestinian geography and history through Judeo-Christian Biblical narratives, and, in the process, de-legitimizing political Palestinian presence in historic Palestine.

Diversity and Activity of Diazotrophs in Great Barrier Reef Surface Waters.

PubMed

Messer, Lauren F; Brown, Mark V; Furnas, Miles J; Carney, Richard L; McKinnon, A D; Seymour, Justin R

2017-01-01

Discrepancies between bioavailable nitrogen (N) concentrations and phytoplankton growth rates in the oligotrophic waters of the Great Barrier Reef (GBR) suggest that undetermined N sources must play a significant role in supporting primary productivity. One such source could be biological dinitrogen (N 2 ) fixation through the activity of "diazotrophic" bacterioplankton. Here, we investigated N 2 fixation and diazotroph community composition over 10° S of latitude within GBR surface waters. Qualitative N 2 fixation rates were found to be variable across the GBR but were relatively high in coastal, inner and outer GBR waters, reaching 68 nmol L -1 d -1 . Diazotroph assemblages, identified by amplicon sequencing of the nifH gene, were dominated by the cyanobacterium Trichodesmium erythraeum , γ-proteobacteria from the Gamma A clade, and δ-proteobacterial phylotypes related to sulfate-reducing genera. However, diazotroph communities exhibited significant spatial heterogeneity, correlated with shifts in dissolved inorganic nutrient concentrations. Specifically, heterotrophic diazotrophs generally increased in relative abundance with increasing concentrations of phosphate and N, while Trichodesmium was proportionally more abundant when concentrations of these nutrients were low. This study provides the first in-depth characterization of diazotroph community composition and N 2 fixation dynamics within the oligotrophic, N-limited surface waters of the GBR. Our observations highlight the need to re-evaluate N cycling dynamics within oligotrophic coral reef systems, to include diverse N 2 fixing assemblages as a potentially significant source of dissolved N within the water column.

Origin and abundance of water in carbonaceous asteroids

NASA Astrophysics Data System (ADS)

Marrocchi, Yves; Bekaert, David V.; Piani, Laurette

2018-01-01

The origin and abundance of water accreted by carbonaceous asteroids remains underconstrained, but would provide important information on the dynamic of the protoplanetary disk. Here we report the in situ oxygen isotopic compositions of aqueously formed fayalite grains in the Kaba and Mokoia CV chondrites. CV chondrite bulk, matrix and fayalite O-isotopic compositions define the mass-independent continuous trend (δ17O = 0.84 ± 0.03 × δ18O - 4.25 ± 0.1), which shows that the main process controlling the O-isotopic composition of the CV chondrite parent body is related to isotopic exchange between 16O-rich anhydrous silicates and 17O- and 18O-rich fluid. Similar isotopic behaviors observed in CM, CR and CO chondrites demonstrate the ubiquitous nature of O-isotopic exchange as the main physical process in establishing the O-isotopic features of carbonaceous chondrites, regardless of their alteration degree. Based on these results, we developed a new approach to estimate the abundance of water accreted by carbonaceous chondrites (quantified by the water/rock ratio) with CM (0.3-0.4) ≥ CR (0.1-0.4) ≥ CV (0.1-0.2) > CO (0.01-0.10). The low water/rock ratios and the O-isotopic characteristics of secondary minerals in carbonaceous chondrites indicate they (i) formed in the main asteroid belt and (ii) accreted a locally derived (inner Solar System) water formed near the snowline by condensation from the gas phase. Such results imply low influx of D- and 17O- and 18O-rich water ice grains from the outer part of the Solar System. The latter is likely due to the presence of a Jupiter-induced gap in the protoplanetary disk that limited the inward drift of outer Solar System material at the exception of particles with size lower than 150 μm such as presolar grains. Among carbonaceous chondrites, CV chondrites show O-isotopic features suggesting potential contribution of 17-18O-rich water that may be related to their older accretion relative to other hydrated

Pico and nanoplankton abundance and carbon stocks along the Brazilian Bight

PubMed Central

Lopes dos Santos, Adriana; Marie, Dominique; Helena Pellizari, Vivian; Pereira Brandini, Frederico; Vaulot, Daniel

2016-01-01

Pico and nanoplankton communities from the Southwest Atlantic Ocean along the Brazilian Bight are poorly described. The hydrography in this region is dominated by a complex system of layered water masses, which includes the warm and oligotrophic Tropical Water (TW), the cold and nutrient rich South Atlantic Central Water (SACW) and the Coastal Water (CW), which have highly variable properties. In order to assess how pico- and nanoplankton communities are distributed in these different water masses, we determined by flow cytometry the abundance of heterotrophic bacteria, Prochlorococcus, Synechococcus and autotrophic pico and nanoeukaryotes along three transects, extending from 23°S to 31°S and 39°W to 49°W. Heterotrophic bacteria (including archaea, maximum of 1.5 × 106 cells mL−1) were most abundant in Coastal and Tropical Water whereas Prochlorococcus was most abundant in open-ocean oligotrophic waters (maximum of 300 × 103 cells mL−1). Synechococcus(up to 81 × 103 cells mL−1), as well as autotrophic pico and nanoeukaryotes seemed to benefit from the influx of nutrient-rich waters near the continental slope. Autotrophic pico and nanoeukaryotes were also abundant in deep chlorophyll maximum (DCM) layers from offshore waters, and their highest abundances were 20 × 103 cells mL−1 and 5 × 103 cells mL−1, respectively. These data are consistent with previous observations in other marine areas where Synechococcus and autotrophic eukaryotes dominate mesotrophic waters, whereas Prochlorococcus dominate in more oligotrophic areas. Regardless of the microbial community structure near the surface, the carbon stock dominance by autotrophic picoeukaryotes near the DCM is possibly linked to vertical mixing of oligotrophic surface waters with the nutrient-rich SACW and their tolerance to lower light levels. PMID:27867760

Seasonal variation in sea turtle density and abundance in the southeast Florida current and surrounding waters

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

Bovery, Caitlin M.; Wyneken, Jeanette

Assessment and management of sea turtle populations is often limited by a lack of available data pertaining to at-sea distributions at appropriate spatial and temporal resolutions. Assessing the spatial and temporal distributions of marine turtles in an open system poses both observational and analytical challenges due to the turtles’ highly migratory nature. Surface counts of marine turtles in waters along the southern part of Florida’s east coast were made in and adjacent to the southeast portion of the Florida Current using standard aerial surveys during 2011 and 2012 to assess their seasonal presence. This area is of particular concern formore » sea turtles as interest increases in offshore energy developments, specifically harnessing the power of the Florida Current. While it is understood that marine turtles use these waters, here we evaluate seasonal variation in sea turtle abundance and density over two years. Density of sea turtles observed within the study area ranged from 0.003 turtles km-2 in the winter of 2011 to 0.064 turtles km-2 in the spring of 2012. As a result, this assessment of marine turtles in the waters off southeast Florida quantifies their in-water abundance across seasons in this area to establish baselines and inform future management strategies of these protected species.« less

Seasonal variation in sea turtle density and abundance in the southeast Florida current and surrounding waters

DOE PAGES

Bovery, Caitlin M.; Wyneken, Jeanette

2015-12-30

Assessment and management of sea turtle populations is often limited by a lack of available data pertaining to at-sea distributions at appropriate spatial and temporal resolutions. Assessing the spatial and temporal distributions of marine turtles in an open system poses both observational and analytical challenges due to the turtles’ highly migratory nature. Surface counts of marine turtles in waters along the southern part of Florida’s east coast were made in and adjacent to the southeast portion of the Florida Current using standard aerial surveys during 2011 and 2012 to assess their seasonal presence. This area is of particular concern formore » sea turtles as interest increases in offshore energy developments, specifically harnessing the power of the Florida Current. While it is understood that marine turtles use these waters, here we evaluate seasonal variation in sea turtle abundance and density over two years. Density of sea turtles observed within the study area ranged from 0.003 turtles km-2 in the winter of 2011 to 0.064 turtles km-2 in the spring of 2012. As a result, this assessment of marine turtles in the waters off southeast Florida quantifies their in-water abundance across seasons in this area to establish baselines and inform future management strategies of these protected species.« less

Bacterial abundance and diversity in pond water supplied with different feeds

NASA Astrophysics Data System (ADS)

Qin, Ya; Hou, Jie; Deng, Ming; Liu, Quansheng; Wu, Chongwei; Ji, Yingjie; He, Xugang

2016-10-01

The abundance and diversity of bacteria in two types of ponds were investigated by quantitative PCR and Illumina MiSeq sequencing. The results revealed that the abundance of bacterial 16S rRNA genes in D ponds (with grass carp fed sudan grass) was significantly lower than that in E ponds (with grass carp fed commercial feed). The microbial communities were dominated by Proteobacteria, Cyanobacteria, Bacteroidetes, and Actinobacteria in both E and D ponds, while the abundance of some genera was significantly different between the two types of ponds. Specifically, some potential pathogens such as Acinetobacter and Aeromonas were found to be significantly decreased, while some probiotics such as Comamonadaceae unclassified and Bacillales unclassified were significantly increased in D ponds. In addition, water quality of D ponds was better than that of E ponds. Temperature, dissolved oxygen and nutrients had significant influence on bacterial communities. The differences in bacterial community compositions between the two types of ponds could be partially explained by the different water conditions.

Natural abundance 17O DNP two-dimensional and surface-enhanced NMR spectroscopy

DOE PAGES

Perras, Frédéric A.; Kobayashi, Takeshi; Pruski, Marek

2015-06-22

Due to its extremely low natural abundance and quadrupolar nature, the 17O nuclide is very rarely used for spectroscopic investigation of solids by NMR without isotope enrichment. Additionally, the applicability of dynamic nuclear polarization (DNP), which leads to sensitivity enhancements of 2 orders of magnitude, to 17O is wrought with challenges due to the lack of spin diffusion and low polarization transfer efficiency from 1H. Here, we demonstrate new DNP-based measurements that extend 17O solid-state NMR beyond its current capabilities. The use of the PRESTO technique instead of conventional 1H– 17O cross-polarization greatly improves the sensitivity and enables the facilemore » measurement of undistorted line shapes and two-dimensional 1H– 17O HETCOR NMR spectra as well as accurate internuclear distance measurements at natural abundance. This was applied for distinguishing hydrogen-bonded and lone 17O sites on the surface of silica gel; the one-dimensional spectrum of which could not be used to extract such detail. As a result, this greatly enhanced sensitivity has enabled, for the first time, the detection of surface hydroxyl sites on mesoporous silica at natural abundance, thereby extending the concept of DNP surface-enhanced NMR spectroscopy to the 17O nuclide.« less

Bacterial Abundance and Activity across Sites within Two Northern Wisconsin Sphagnum Bogs.

PubMed

Fisher; Graham; Graham

1998-11-01

Abstract Bacterial abundance, temperature, pH, and dissolved organic carbon (DOC) concentration were compared across surface sites within and between two northern Wisconsin Sphagnum peatlands over the summer seasons in 1995 and 1996. Sites of interest were the Sphagnum mat surface, the water-filled moat (lagg) at the bog margin, and the bog lake littoral zone. Significant differences in both bacterial populations and water chemistry were observed between sites. pH was highest in the lake and lowest in the mat at both bogs; the opposite was true for DOC. Large populations of bacteria were present in surface interstitial water from the mat; abundance in this site was consistently higher than in the moat or lake. Bacterial abundance also increased across sites of increasing DOC concentration and declining pH. Bacterial activities (rates of [3H]leucine incorporation) and growth in dilution cultures (with grazers removed) were also assessed in lake, moat, and mat sites. Results using these measures generally supported the trends observed in abundance, although high rates of [3H]leucine incorporation were recorded in the moat at one of the bogs. Our results indicate that bacterial populations in Sphagnum peatlands are not adversely affected by acidity, and that DOC may be more important than pH in determining bacterial abundance in these environments.

Water Table Depth Reconstruction in Ombrotrophic Peatlands Using Biomarker Abundance Ratios and Compound-Specific Hydrogen Isotope Composition

NASA Astrophysics Data System (ADS)

Nichols, J. E.; Jackson, S. T.; Booth, R. K.; Pendall, E. G.; Huang, Y.

2005-12-01

Sediment cores from ombrotrophic peat bogs provide sensitive records of changes in precipitation/evaporation (P/E) balance. Various proxies have been developed to reconstruct surface moisture conditions in peat bogs, including testate amoebae, plant macrofossils, and peat humification. Studying species composition of testate amoeba assemblages is time consuming and requires specialized training. Humification index can be influenced by environmental factors other than moisture balance. The plant macrofossil proxy is less quantitative and cannot be performed on highly decomposed samples. We demonstrate that the ratio of C23 alkane to C29 alkane abundance may provide a simple alternative or complementary means of tracking peatland water-table depth. Data for this proxy can be collected quickly using a small sample (100 mg dry). Water-table depth decreases during drought, and abundance of Sphagnum, the dominant peat-forming genus, decreases as vascular plants increase. Sphagnum moss produces mainly medium chain-length alkanes (C21-C25) while vascular plants (grasses and shrubs) produce primarily longer chain-length alkanes (C27-C31). Therefore, C23:C29 n-alkane ratios quantitatively track the water table depth fluctuations in peat bogs. We compared C23:C29 n-alkane ratios in a core from Minden Bog (southeastern Michigan) with water table depth reconstructions based on testate-amoeba assemblages and humification. The 184-cm core spans the past ~3kyr of continuous peat deposition in the bog. Our results indicate that the alkane ratios closely track the water table depth variations, with C29 most abundant during droughts. We also explored the use of D/H ratios in Sphagnum biomarkers as a water-table depth proxy. Compound-specific hydrogen isotope ratio analyses were performed on Sphagnum biomarkers: C23 and C25 alkane and C24 acid. Dry periods are represented in these records by an enrichment of deuterium in these Sphagnum-specific compounds. These events also correlate

Abundance and δ13C values of fatty acids in lacustrine surface sediments: Relationships with in-lake methane concentrations

NASA Astrophysics Data System (ADS)

Stötter, Tabea; Bastviken, David; Bodelier, Paul L. E.; van Hardenbroek, Maarten; Rinta, Päivi; Schilder, Jos; Schubert, Carsten J.; Heiri, Oliver

2018-07-01

Proxy-indicators in lake sediments provide the only approach by which the dynamics of in-lake methane cycling can be examined on multi-decadal to centennial time scales. This information is necessary to constrain how lacustrine methane production, oxidation and emissions are expected to respond to global change drivers. Several of the available proxies for reconstructing methane cycle changes of lakes rely on interpreting past changes in the abundance or relevance of methane oxidizing bacteria (MOB), either directly (e.g. via analysis of bacterial lipids) or indirectly (e.g. via reconstructions of the past relevance of MOB in invertebrate diet). However, only limited information is available about the extent to which, at the ecosystem scale, variations in abundance and availability of MOB reflect past changes in in-lake methane concentrations. We present a study examining the abundances of fatty acids (FAs), particularly of 13C-depleted FAs known to be produced by MOB, relative to methane concentrations in 29 small European lakes. 39 surface sediment samples were obtained from these lakes and FA abundances were compared with methane concentrations measured at the lake surface, 10 cm above the sediments and 10 cm within the sediments. Three of the FAs in the surface sediment samples, C16:1ω7c, C16:1ω5c/t, and C18:1ω7c were characterized by lower δ13C values than the remaining FAs. We show that abundances of these FAs, relative to other short-chain FAs produced in lake ecosystems, are related with sedimentary MOB concentrations assessed by quantitative polymerase chain reaction (qPCR). We observed positive relationships between methane concentrations and relative abundances of C16:1ω7c, C16:1ω5c/t, and C18:1ω7c and the sum of these FAs. For the full dataset these relationships were relatively weak (Spearman's rank correlation (rs) of 0.34-0.43) and not significant if corrected for multiple testing. However, noticeably stronger and statistically significant

Episodic fresh surface waters in the Eocene Arctic Ocean

NASA Astrophysics Data System (ADS)

Brinkhuis, Henk; Schouten, Stefan; Collinson, Margaret E.; Sluijs, Appy; Damsté, Jaap S. Sinninghe; Dickens, Gerald R.; Huber, Matthew; Cronin, Thomas M.; Onodera, Jonaotaro; Takahashi, Kozo; Bujak, Jonathan P.; Stein, Ruediger; van der Burgh, Johan; Eldrett, James S.; Harding, Ian C.; Lotter, André F.; Sangiorgi, Francesca; Cittert, Han Van Konijnenburg-Van; de Leeuw, Jan W.; Matthiessen, Jens; Backman, Jan; Moran, Kathryn; Expedition 302 Scientists

2006-06-01

It has been suggested, on the basis of modern hydrology and fully coupled palaeoclimate simulations, that the warm greenhouse conditions that characterized the early Palaeogene period (55-45Myr ago) probably induced an intensified hydrological cycle with precipitation exceeding evaporation at high latitudes. Little field evidence, however, has been available to constrain oceanic conditions in the Arctic during this period. Here we analyse Palaeogene sediments obtained during the Arctic Coring Expedition, showing that large quantities of the free-floating fern Azolla grew and reproduced in the Arctic Ocean by the onset of the middle Eocene epoch (~50Myr ago). The Azolla and accompanying abundant freshwater organic and siliceous microfossils indicate an episodic freshening of Arctic surface waters during an ~800,000-year interval. The abundant remains of Azolla that characterize basal middle Eocene marine deposits of all Nordic seas probably represent transported assemblages resulting from freshwater spills from the Arctic Ocean that reached as far south as the North Sea. The termination of the Azolla phase in the Arctic coincides with a local sea surface temperature rise from ~10°C to 13°C, pointing to simultaneous increases in salt and heat supply owing to the influx of waters from adjacent oceans. We suggest that onset and termination of the Azolla phase depended on the degree of oceanic exchange between Arctic Ocean and adjacent seas.

Episodic fresh surface waters in the Eocene Arctic Ocean

USGS Publications Warehouse

Brinkhuis, H.; Schouten, S.; Collinson, M.E.; Sluijs, A.; Damste, J.S.S.; Dickens, G.R.; Huber, M.; Cronin, T. M.; Onodera, J.; Takahashi, K.; Bujak, J.P.; Stein, R.; Van Der Burgh, J.; Eldrett, J.S.; Harding, I.C.; Lotter, A.F.; Sangiorgi, F.; Cittert, H.V.K.V.; De Leeuw, J. W.; Matthiessen, J.; Backman, J.; Moran, K.

2006-01-01

It has been suggested, on the basis of modern hydrology and fully coupled palaeoclimate simulations, that the warm greenhouse conditions that characterized the early Palaeogene period (55-45 Myr ago) probably induced an intensified hydrological cycle with precipitation exceeding evaporation at high latitudes. Little field evidence, however, has been available to constrain oceanic conditions in the Arctic during this period. Here we analyse Palaeogene sediments obtained during the Arctic Coring Expedition, showing that large quantities of the free-floating fern Azolla grew and reproduced in the Arctic Ocean by the onset of the middle Eocene epoch (???50 Myr ago). The Azolla and accompanying abundant freshwater organic and siliceous microfossils indicate an episodic freshening of Arctic surface waters during an ???800,000-year interval. The abundant remains of Azolla that characterize basal middle Eocene marine deposits of all Nordic seas probably represent transported assemblages resulting from freshwater spills from the Arctic Ocean that reached as far south as the North Sea. The termination of the Azolla phase in the Arctic coincides with a local sea surface temperature rise from ???10??C to 13??C, pointing to simultaneous increases in salt and heat supply owing to the influx of waters from adjacent oceans. We suggest that onset and termination of the Azolla phase depended on the degree of oceanic exchange between Arctic Ocean and adjacent seas. ?? 2006 Nature Publishing Group.

Water guns affect abundance and behavior of bigheaded carp and native fish differently

USGS Publications Warehouse

Rivera, Jose; Glover, David C.; Kocovsky, Patrick; Garvey, James E.; Gaikowski, Mark; Jensen, Nathan R.; Adams, Ryan F.

2018-01-01

Water guns have shown the potential to repel nuisance aquatic organisms. This study examines the effects of exposure to a 1966.4 cm3 seismic water gun array (two guns) on the abundance and behavior of Bighead Carp Hypophthalmichthys nobilis, Silver Carp H. molitrix (collectively referred to as bigheaded carp) and native fishes (e.g., Smallmouth Buffalo Ictiobus bubalus). Water guns were deployed in a channel that connects the Illinois River to backwater quarry pits that contained a large transient population of bigheaded carp. To evaluate the effect of water guns, mobile side-looking split-beam hydroacoustic surveys were conducted before, during and between replicated water gun firing periods. Water guns did not affect abundance of bigheaded carp, but abundance of native fish detected during the firing treatment was 43 and 34% lower than the control and water guns off treatments, respectively. The proximity of bigheaded carp to the water gun array was similar between the water guns on and water guns off treatments. In contrast, the closest detected native fish were detected farther from the water guns during the water guns on treatment (mean ± SE, 32.38 ± 3.32 m) than during the water guns off treatment (15.04 ± 1.59 m). The water gun array had a greater impact on native fish species than on bigheaded carp. Caution should be taken to the extrapolation of these results to other fish species and to fish exposed to water guns in different environments (e.g., reduced shoreline interaction) or exposure to a larger array of water guns, or for use of water guns for purposes other than a barrier.

Reliable Quantitative Mineral Abundances of the Martian Surface using THEMIS

NASA Astrophysics Data System (ADS)

Smith, R. J.; Huang, J.; Ryan, A. J.; Christensen, P. R.

2013-12-01

The following presents a proof of concept that given quality data, Thermal Emission Imaging System (THEMIS) data can be used to derive reliable quantitative mineral abundances of the Martian surface using a limited mineral library. The THEMIS instrument aboard the Mars Odyssey spacecraft is a multispectral thermal infrared imager with a spatial resolution of 100 m/pixel. The relatively high spatial resolution along with global coverage makes THEMIS datasets powerful tools for comprehensive fine scale petrologic analyses. However, the spectral resolution of THEMIS is limited to 8 surface sensitive bands between 6.8 and 14.0 μm with an average bandwidth of ~ 1 μm, which complicates atmosphere-surface separation and spectral analysis. This study utilizes the atmospheric correction methods of both Bandfield et al. [2004] and Ryan et al. [2013] joined with the iterative linear deconvolution technique pioneered by Huang et al. [in review] in order to derive fine-scale quantitative mineral abundances of the Martian surface. In general, it can be assumed that surface emissivity combines in a linear fashion in the thermal infrared (TIR) wavelengths such that the emitted energy is proportional to the areal percentage of the minerals present. TIR spectra are unmixed using a set of linear equations involving an endmember library of lab measured mineral spectra. The number of endmembers allowed in a spectral library are restricted to a quantity of n-1 (where n = the number of spectral bands of an instrument), preserving one band for blackbody. Spectral analysis of THEMIS data is thus allowed only seven endmembers. This study attempts to prove that this limitation does not prohibit the derivation of meaningful spectral analyses from THEMIS data. Our study selects THEMIS stamps from a region of Mars that is well characterized in the TIR by the higher spectral resolution, lower spatial resolution Thermal Emission Spectrometer (TES) instrument (143 bands at 10 cm-1 sampling and 3

Interactions between soil texture, water, and nutrients control patterns of biocrusts abundance and structure

NASA Astrophysics Data System (ADS)

Young, Kristina; Bowker, Matthew; Reed, Sasha; Howell, Armin

2017-04-01

Heterogeneity in the abiotic environment structures biotic communities by controlling niche space and parameters. This has been widely observed and demonstrated in vascular plant and other aboveground communities. While soil organisms are presumably also strongly influenced by the physical and chemical dimensions of the edaphic environment, there are fewer studies linking the development, structure, productivity or function of surface soil communities to specific edaphic gradients. Here, we use biological soil crusts (biocrusts) as a model system to determine mechanisms regulating community structure of soil organisms. We chose soil texture to serve as an edaphic gradient because of soil texture's influence over biocrust distribution on a landscape level. We experimentally manipulated texture in constructed soil, and simultaneously manipulated two main outcomes of texture, water and nutrient availability, to determine the mechanism underlying texture's influence on biocrust abundance and structure. We grew biocrust communities from a field-sourced inoculum on four different soil textures, sieved from the same parent soil material, manipulating watering levels and nutrient additions across soil textures in a full-factorial design over a 5-month period of time. We measured abundance and structure of biocrusts over time, and measured two metrics of function, N2 fixation rates and soil stabilization, at the conclusion of the experiment. Our results showed finer soil textures resulted in faster biocrust community development and dominance by mosses, whereas coarser textures grew more slowly and had biocrust communities dominated by cyanobacteria and lichen. Additionally, coarser textured soils contained cyanobacterial filaments significantly deeper into the soil profile than fine textured soils. N2-fixation values increased with increasing moss cover and decreased with increasing cyanobacterial cover, however, the rate of change depended on soil texture and water amount

Effects of farmhouse hotel and paper mill effluents on bacterial community structures in sediment and surface water of Nanxi River, China.

PubMed

Lu, Xiao-Ming; Lu, Peng-Zhen

2014-11-01

The pyrosequencing technique was used to evaluate bacterial community structures in sediment and surface water samples taken from Nanxi River receiving effluents from a paper mill and a farmhouse hotel, respectively. For each sample, 4,610 effective bacterial sequences were selected and used to do the analysis of diversity and abundance, respectively. Bacterial phylotype richness in the sediment sample without effluent input was higher than the other samples, and the surface water sample with addition of effluent from the paper mill contained the least richness. Effluents from both the paper mill and farmhouse hotel have a potential to reduce the bacterial diversity and abundance in the sediment and surface water, especially it is more significant in the sediment. The effect of the paper mill effluent on the sediment and surface water bacterial communities was more serious than that of the farmhouse hotel effluent. Characterization of microbial community structures in the sediment and surface water from two tributaries of the downstream river indicated that various effluents from the paper mill and farmhouse hotel have the similar potential to decrease the natural variability in riverine microbial ecosystems.

Aerobic methane production in surface waters of the Gulf of Mexico

NASA Astrophysics Data System (ADS)

Finke, N.; Crespo-Medina, M.; Schweers, J.; Joye, S. B.

2011-12-01

Near surface water of the global oceans often show elevated methane concentrations compared to the water column below with concentrations in supersaturation in regard to the atmosphere (Lamontagne et al. 1973), resulting in a source of this potent greenhouse gas to the atmosphere. The mechanisms leading to methane supersaturation in surface waters remains unclear. Incubations with Trichodesmium-containing Pacific surface water suggested methylphosphonate as potential methane precursor under phosphate limiting conditions (Karl et al. 2008), whereas in phosphate rich Arctic surface waters, DMSP addition stimulated methane production (Damm et al. 2010). Surface waters of the Gulf of Mexico typically exhibit a methane maximum that is conincident with the deep chlorophyll maximum, below the depths where Trichodesmium is abundant. Addition of methylphosphonate, dimethylsulfoniopropionate (DMSP) or methane thiol (MeSH), the proposed methane precursor in DMSP conversion to methane, to oxic sea water did not affect methane production within the chlorophyll maximum at most stations, whereas methyl phosphonate addition stimulated methane production in the surface water and proposed deep Trichodesmium horizon. Pre-filtration of the water through a 10 μm sieve, which eliminated Trichodesmium, or through a 1.2 μm filter, which eliminated additional cyanobacteria such as Synechococcus, did not reduce methane production. Under dark oxic and dark anoxic conditions, however, methane production was reduced 5 and 7-20 fold, respectively, indicating that anerobic methane production in anoxic microniches is not responsible for the methane production. The reduction of methane production under dark conditions suggests that methane production is, in some yet unrecognized way, linked to phototrophic metabolism. Cyanobacteria are likely not responsible for the observed aerobic methane production in the surface waters of the Gulf of Mexico and while methylphosphonate is a potential

Distribution and abundance of larval fish in the nearshore waters of western Lake Huron

USGS Publications Warehouse

O'Gorman, Robert

1983-01-01

Ichthyoplankton was collected at 17 nearshore (bottom depth ≥5 m but ≤10 m) sites in western Lake Huron during 1973–75 with a 0.5-m net of 351-micron mesh towed at 99 m/min. Larvae of rainbow smelt (Osmerus mordax) dominated late spring and early summer catches and larvae of alewives (Alosa pseudoharengus) the midsummer catches. Larval yellow perch (Perca flavescens) were caught in early summer but were rarely the dominant species. The time of spawning and hatching, and thus occurrence of larvae, differed between areas but was less variable for alewives than for yellow perch. The appearance of larvae in Saginaw Bay was followed successively by their appearance in southern, central, and northern Lake Huron. Rainbow smelt were most abundant in northern Lake Huron and yellow perch and alewives in inner Saginaw Bay. Densities of either rainbow smelt or alewives occasionally exceeded 1/m3, whereas those of yellow perch never exceeded 0.1/m3. Abundance of alewives was usually highest 1 to 3 m beneath the surface and that of rainbow smelt 2 to at least 6 m beneath the surface. Important nursery areas of rainbow smelt were in bays and off irregular coastlines and those of yellow perch were in bays. All nearshore waters seemed equally important as nursery areas of alewives.

Water abstraction affects abundance, size-structure and growth of two threatened cyprinid fishes

PubMed Central

Merciai, Roberto; Molons-Sierra, Carlota; Sabater, Sergi; García-Berthou, Emili

2017-01-01

Hydrologic alteration is a major threat to freshwater biota, and particularly fish, in many river courses around the world. We analyzed and compared the effects of water abstraction on two threatened cyprinid fishes of contrasting ecology (the Mediterranean barbel Barbus meridionalis and the Catalan chub Squalius laietanus) in a Mediterranean stream. We compared abundance, size-structure, growth, and condition of both species across perennial and artificially intermittent reaches affected by water abstraction. Both species were less abundant, had scarce large individuals, and displayed slower growth rates (length-at-age) in intermittent reaches, showing clear detrimental effects of water diversion. Mixed-effect models of scale increments showed variation among individuals and among sites, years and age classes for both species. The larger-sized, water-column species (chub) disappeared or was rare in many intermittent reaches. The barbel present in intermittent reaches showed better somatic condition than in sites with permanent flow, perhaps due to reduced competition after rewetting or colonization by better fitted individuals. This benthic, rheophilic species seems more resilient to moderate water abstraction than chub. Many effects of water flow intermittency were only detected on fish life-history traits when accounting for natural, often non-linear, variation, along upstream-downstream gradients. Our results suggest that abundance was the strongest indicator of effects of water abstraction on fish populations, whereas condition was a more labile trait, rapidly recovering from anthropogenic disturbance. PMID:28414787

Groundwater-surface water mixing shifts ecological assembly processes and stimulates organic carbon turnover.

PubMed

Stegen, James C; Fredrickson, James K; Wilkins, Michael J; Konopka, Allan E; Nelson, William C; Arntzen, Evan V; Chrisler, William B; Chu, Rosalie K; Danczak, Robert E; Fansler, Sarah J; Kennedy, David W; Resch, Charles T; Tfaily, Malak

2016-04-07

Environmental transitions often result in resource mixtures that overcome limitations to microbial metabolism, resulting in biogeochemical hotspots and moments. Riverine systems, where groundwater mixes with surface water (the hyporheic zone), are spatially complex and temporally dynamic, making development of predictive models challenging. Spatial and temporal variations in hyporheic zone microbial communities are a key, but understudied, component of riverine biogeochemical function. Here, to investigate the coupling among groundwater-surface water mixing, microbial communities and biogeochemistry, we apply ecological theory, aqueous biogeochemistry, DNA sequencing and ultra-high-resolution organic carbon profiling to field samples collected across times and locations representing a broad range of mixing conditions. Our results indicate that groundwater-surface water mixing in the hyporheic zone stimulates heterotrophic respiration, alters organic carbon composition, causes ecological processes to shift from stochastic to deterministic and is associated with elevated abundances of microbial taxa that may degrade a broad suite of organic compounds.

Finding water scarcity amid abundance using human-natural system models.

PubMed

Jaeger, William K; Amos, Adell; Bigelow, Daniel P; Chang, Heejun; Conklin, David R; Haggerty, Roy; Langpap, Christian; Moore, Kathleen; Mote, Philip W; Nolin, Anne W; Plantinga, Andrew J; Schwartz, Cynthia L; Tullos, Desiree; Turner, David P

2017-11-07

Water scarcity afflicts societies worldwide. Anticipating water shortages is vital because of water's indispensable role in social-ecological systems. But the challenge is daunting due to heterogeneity, feedbacks, and water's spatial-temporal sequencing throughout such systems. Regional system models with sufficient detail can help address this challenge. In our study, a detailed coupled human-natural system model of one such region identifies how climate change and socioeconomic growth will alter the availability and use of water in coming decades. Results demonstrate how water scarcity varies greatly across small distances and brief time periods, even in basins where water may be relatively abundant overall. Some of these results were unexpected and may appear counterintuitive to some observers. Key determinants of water scarcity are found to be the cost of transporting and storing water, society's institutions that circumscribe human choices, and the opportunity cost of water when alternative uses compete. Published under the PNAS license.

Properties of six short-period massive binaries: A study of the effects of binarity on surface chemical abundances

NASA Astrophysics Data System (ADS)

Martins, F.; Mahy, L.; Hervé, A.

2017-11-01

Context. A significant percentage of massive stars are found in multiple systems. The effect of binarity on stellar evolution is poorly constrained. In particular, the role of tides and mass transfer on surface chemical abundances is not constrained observationally. Aims: The aim of this study is to investigate the effect of binarity on the stellar properties and surface abundances of massive binaries. Methods: We performed a spectroscopic analysis of six Galactic massive binaries. We obtained the spectra of individual components via a spectral disentangling method and subsequently analyzed these spectra by means of atmosphere models. The stellar parameters and CNO surface abundances were determined. Results: Most of these six systems are comprised of main-sequence stars. Three systems are detached, two are in contact, and no information is available for the sixth system. For 11 out of the 12 stars studied, the surface abundances are only mildly affected by stellar evolution and mixing. The surface abundances are not different from those of single stars within the uncertainties. The secondary of XZ Cep is strongly chemically enriched. Considering previous determinations of surface abundances in massive binary systems suggests that the effect of tides on chemical mixing is limited, whereas the mass transfer and removal of outer layers of the mass donor leads to the appearance of chemically processed material at the surface, although this is not systematic. The evolutionary masses of the components of our six systems are on average 16.5% higher than the dynamical masses. Some systems seem to have reached synchronization, while others may still be in a transitory phase. Based on observations made with the SOPHIE spectrograph on the 1.93 m telescope at Observatoire de Haute-Provence (OHP, CNRS/AMU), France.

Spatial patterns of distribution, abundance, and species diversity of small odontocetes estimated using density surface modeling with line transect sampling

NASA Astrophysics Data System (ADS)

Kanaji, Yu; Okazaki, Makoto; Miyashita, Tomio

2017-06-01

Spatial patterns of distribution, abundance, and species diversity of small odontocetes including species in the Delphinidae and Phocoenidae families were investigated using long-term dedicated sighting survey data collected between 1983 and 2006 in the North Pacific. Species diversity indices were calculated from abundance estimated using density surface modeling of line-transect data. The estimated abundance ranged from 19,521 individuals in killer whale to 1,886,022 in pantropical spotted dolphin. The predicted density maps showed that the habitats of small odontocetes corresponded well with distinct oceanic domains. Species richness was estimated to be highest between 30 and 40°N where warm- and cold-water currents converge. Simpson's Diversity Index showed latitudinal diversity gradients of decreasing species numbers toward the poles. Higher diversity was also estimated in the coastal areas and the zonal areas around 35-42°N. Coastal-offshore gradients and latitudinal gradients are known for many taxa. The zonal areas around 35°N and 40°N coincide with the Kuroshio Current and its extension and the subarctic boundary, respectively. These results suggest that the species diversity of small odontocetes primarily follows general patterns of latitudinal and longitudinal gradients, while the confluence of faunas originating in distinct water masses increases species diversify in frontal waters around 30-40°N. Population densities tended to be higher for the species inhabiting higher latitudes, but were highest for intermediate latitudes at approximately 35-40°N. According to latitudinal gradients in water temperature and biological productivity, the costs for thermoregulation will decrease in warmer low latitudes, while feeding efficiency will increase in colder high latitudes. These trade-offs could optimize population density in intermediate latitudes.

Groundwater–surface water mixing shifts ecological assembly processes and stimulates organic carbon turnover

PubMed Central

Stegen, James C.; Fredrickson, James K.; Wilkins, Michael J.; Konopka, Allan E.; Nelson, William C.; Arntzen, Evan V.; Chrisler, William B.; Chu, Rosalie K.; Danczak, Robert E.; Fansler, Sarah J.; Kennedy, David W.; Resch, Charles T.; Tfaily, Malak

2016-01-01

Environmental transitions often result in resource mixtures that overcome limitations to microbial metabolism, resulting in biogeochemical hotspots and moments. Riverine systems, where groundwater mixes with surface water (the hyporheic zone), are spatially complex and temporally dynamic, making development of predictive models challenging. Spatial and temporal variations in hyporheic zone microbial communities are a key, but understudied, component of riverine biogeochemical function. Here, to investigate the coupling among groundwater–surface water mixing, microbial communities and biogeochemistry, we apply ecological theory, aqueous biogeochemistry, DNA sequencing and ultra-high-resolution organic carbon profiling to field samples collected across times and locations representing a broad range of mixing conditions. Our results indicate that groundwater–surface water mixing in the hyporheic zone stimulates heterotrophic respiration, alters organic carbon composition, causes ecological processes to shift from stochastic to deterministic and is associated with elevated abundances of microbial taxa that may degrade a broad suite of organic compounds. PMID:27052662

Occurrence of Diatoms in Lakeside Wells in Northern New Jersey as an Indicator of the Effect of Surface Water on Ground-Water Quality

USGS Publications Warehouse

Reilly, Timothy J.; Walker, Christopher E.; Baehr, Arthur L.; Schrock, Robin M.; Reinfelder, John R.

2006-01-01

In a novel approach for detecting ground-water/surface-water interaction, diatoms were used as an indicator that surface water affects ground-water quality in lakeside communities in northern New Jersey. The presence of diatoms, which are abundant in lakes, in adjacent domestic wells demonstrated that ground water in these lakeside communities was under the direct influence of surface water. Entire diatom frustules were present in 17 of 18 water samples collected in August 1999 from domestic wells in communities surrounding Cranberry Lake and Lake Lackawanna. Diatoms in water from the wells were of the same genus as those found in the lakes. The presence of diatoms in the wells, together with the fact that most static and stressed water levels in wells were below the elevation of the lake surfaces, indicates that ground-water/surface-water interaction is likely. Ground-water/surface-water interaction also probably accounts for the previously documented near-ubiquitous presence of methyl tertiary-butyl ether in the ground-water samples. Recreational use of lakes for motor boating and swimming, the application of herbicides for aquatic weed control, runoff from septic systems and roadways, and the presence of waterfowl all introduce contaminants to the lake. Samples from 4 of the 18 wells contained Navicula spp., a documented significant predictor of Giardia and Cryptosporidium. Because private well owners in New Jersey generally are not required to regularly monitor their wells, and tests conducted by public-water suppliers may not be sensitive to indicators of ground-water/surface-water interaction, these contaminants may remain undetected. The presence of diatoms in wells in similar settings can warn of lake/well interactions in the absence of other indicators.

What is Neptune's D/H ratio really telling us about its water abundance?

NASA Astrophysics Data System (ADS)

Ali-Dib, Mohamad; Lakhlani, Gunjan

2018-05-01

We investigate the deep-water abundance of Neptune using a simple two-component (core + envelope) toy model. The free parameters of the model are the total mass of heavy elements in the planet (Z), the mass fraction of Z in the envelope (fenv), and the D/H ratio of the accreted building blocks (D/Hbuild).We systematically search the allowed parameter space on a grid and constrain it using Neptune's bulk carbon abundance, D/H ratio, and interior structure models. Assuming solar C/O ratio and cometary D/H for the accreted building blocks are forming the planet, we can fit all of the constraints if less than ˜15 per cent of Z is in the envelope (f_{env}^{median} ˜ 7 per cent), and the rest is locked in a solid core. This model predicts a maximum bulk oxygen abundance in Neptune of 65× solar value. If we assume a C/O of 0.17, corresponding to clathrate-hydrates building blocks, we predict a maximum oxygen abundance of 200× solar value with a median value of ˜140. Thus, both cases lead to oxygen abundance significantly lower than the preferred value of Cavalié et al. (˜540× solar), inferred from model-dependent deep CO observations. Such high-water abundances are excluded by our simple but robust model. We attribute this discrepancy to our imperfect understanding of either the interior structure of Neptune or the chemistry of the primordial protosolar nebula.

ORTHO-TO-PARA ABUNDANCE RATIO OF WATER ION IN COMET C/2001 Q4 (NEAT): IMPLICATION FOR ORTHO-TO-PARA ABUNDANCE RATIO OF WATER

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

Shinnaka, Yoshiharu; Kawakita, Hideyo; Kobayashi, Hitomi

2012-04-20

The ortho-to-para abundance ratio (OPR) of cometary molecules is considered to be one of the primordial characteristics of cometary ices, and contains information concerning their formation. Water is the most abundant species in cometary ices, and OPRs of water in comets have been determined from infrared spectroscopic observations of H{sub 2}O rovibrational transitions so far. In this paper, we present a new method to derive OPR of water in comets from the high-dispersion spectrum of the rovibronic emission of H{sub 2}O{sup +} in the optical wavelength region. The rovibronic emission lines of H{sub 2}O{sup +} are sometimes contaminated by othermore » molecular emission lines but they are not affected seriously by telluric absorption compared with near-infrared observations. Since H{sub 2}O{sup +} ions are mainly produced from H{sub 2}O by photoionization in the coma, the OPR of H{sub 2}O{sup +} is considered to be equal to that of water based on the nuclear spin conservation through the reaction. We have developed a fluorescence excitation model of H{sub 2}O{sup +} and applied it to the spectrum of comet C/2001 Q4 (NEAT). The derived OPR of water is 2.54{sup +0.32}{sub -0.25}, which corresponds to a nuclear spin temperature (T{sub spin}) of 30{sup +10}{sub -4} K. This is consistent with the previous value determined in the near-infrared for the same comet (OPR = 2.6 {+-} 0.3, T{sub spin} = 31{sup +11}{sub -5} K).« less

Finding water scarcity amid abundance using human–natural system models

PubMed Central

Amos, Adell; Bigelow, Daniel P.; Chang, Heejun; Conklin, David R.; Haggerty, Roy; Langpap, Christian; Moore, Kathleen; Mote, Philip W.; Nolin, Anne W.; Plantinga, Andrew J.; Schwartz, Cynthia L.; Tullos, Desiree; Turner, David P.

2017-01-01

Water scarcity afflicts societies worldwide. Anticipating water shortages is vital because of water’s indispensable role in social-ecological systems. But the challenge is daunting due to heterogeneity, feedbacks, and water’s spatial-temporal sequencing throughout such systems. Regional system models with sufficient detail can help address this challenge. In our study, a detailed coupled human–natural system model of one such region identifies how climate change and socioeconomic growth will alter the availability and use of water in coming decades. Results demonstrate how water scarcity varies greatly across small distances and brief time periods, even in basins where water may be relatively abundant overall. Some of these results were unexpected and may appear counterintuitive to some observers. Key determinants of water scarcity are found to be the cost of transporting and storing water, society’s institutions that circumscribe human choices, and the opportunity cost of water when alternative uses compete. PMID:29078299

Water at surfaces with tunable surface chemistries

NASA Astrophysics Data System (ADS)

Sanders, Stephanie E.; Vanselous, Heather; Petersen, Poul B.

2018-03-01

Aqueous interfaces are ubiquitous in natural environments, spanning atmospheric, geological, oceanographic, and biological systems, as well as in technical applications, such as fuel cells and membrane filtration. Where liquid water terminates at a surface, an interfacial region is formed, which exhibits distinct properties from the bulk aqueous phase. The unique properties of water are governed by the hydrogen-bonded network. The chemical and physical properties of the surface dictate the boundary conditions of the bulk hydrogen-bonded network and thus the interfacial properties of the water and any molecules in that region. Understanding the properties of interfacial water requires systematically characterizing the structure and dynamics of interfacial water as a function of the surface chemistry. In this review, we focus on the use of experimental surface-specific spectroscopic methods to understand the properties of interfacial water as a function of surface chemistry. Investigations of the air-water interface, as well as efforts in tuning the properties of the air-water interface by adding solutes or surfactants, are briefly discussed. Buried aqueous interfaces can be accessed with careful selection of spectroscopic technique and sample configuration, further expanding the range of chemical environments that can be probed, including solid inorganic materials, polymers, and water immiscible liquids. Solid substrates can be finely tuned by functionalization with self-assembled monolayers, polymers, or biomolecules. These variables provide a platform for systematically tuning the chemical nature of the interface and examining the resulting water structure. Finally, time-resolved methods to probe the dynamics of interfacial water are briefly summarized before discussing the current status and future directions in studying the structure and dynamics of interfacial water.

Determination of phytoplankton abundances (Chlorophyll-a) in the optically complex inland water - The Baltic Sea.

PubMed

Zhang, Daoxi; Lavender, Samantha; Muller, Jan-Peter; Walton, David; Karlson, Bengt; Kronsell, Johan

2017-12-01

A novel approach, termed Summed Positive Peaks (SPP), is proposed for determining phytoplankton abundances (Chlorophyll-a or Chl-a) and surface phytoplankton bloom extent in the optically complex Baltic Sea. The SPP approach is established on the basis of a baseline subtraction method using Rayleigh corrected top-of-atmosphere data from the Medium Resolution Imaging Spectrometer (MERIS) measurements. It calculates the reflectance differences between phytoplankton related signals observed in the MERIS red and near infrared (NIR) bands, such as sun-induced chlorophyll fluorescence (SICF) and the backscattering at 709nm, and considers the summation of the positive line heights for estimating Chl-a concentrations. The SPP algorithm is calibrated against near coincident in situ data collected from three types of phytoplankton dominant waters encountered in the Baltic Sea during 2010 (N=379). The validation results show that the algorithm is capable of retrieving Chl-a concentrations ranging from 0.5 to 3mgm -3 , with an RMSE of 0.24mgm -3 (R 2 =0.69, N=264). Additionally, the comparison results with several Chl-a algorithms demonstrates the robustness of the SPP approach and its sensitivity to low to medium biomass waters. Based on the red and NIR reflectance features, a flagging method is also proposed to distinguish intensive surface phytoplankton blooms from the background water. Copyright © 2017 Elsevier B.V. All rights reserved.

Temporal changes in endmember abundances, liquid water and water vapor over vegetation at Jasper Ridge

NASA Technical Reports Server (NTRS)

Roberts, Dar A.; Green, Robert O.; Sabol, Donald E.; Adams, John B.

1993-01-01

Imaging spectrometry offers a new way of deriving ecological information about vegetation communities from remote sensing. Applications include derivation of canopy chemistry, measurement of column atmospheric water vapor and liquid water, improved detectability of materials, more accurate estimation of green vegetation cover and discrimination of spectrally distinct green leaf, non-photosynthetic vegetation (NPV: litter, wood, bark, etc.) and shade spectra associated with different vegetation communities. Much of our emphasis has been on interpreting Airborne Visible/Infrared Imaging Spectrometry (AVIRIS) data spectral mixtures. Two approaches have been used, simple models, where the data are treated as a mixture of 3 to 4 laboratory/field measured spectra, known as reference endmembers (EM's), applied uniformly to the whole image, to more complex models where both the number of EM's and the types of EM's vary on a per-pixel basis. Where simple models are applied, materials, such as NPV, which are spectrally similar to soils, can be discriminated on the basis of residual spectra. One key aspect is that the data are calibrated to reflectance and modeled as mixtures of reference EM's, permitting temporal comparison of EM fractions, independent of scene location or data type. In previous studies the calibration was performed using a modified-empirical line calibration, assuming a uniform atmosphere across the scene. In this study, a Modtran-based calibration approach was used to map liquid water and atmospheric water vapor and retrieve surface reflectance from three AVIRIS scenes acquired in 1992 over the Jasper Ridge Biological Preserve. The data were acquired on June 2nd, September 4th and October 6th. Reflectance images were analyzed as spectral mixtures of reference EM's using a simple 4 EM model. Atmospheric water vapor derived from Modtran was compared to elevation, and community type. Liquid water was compare to the abundance of NPV, Shade and Green Vegetation

Reconciling LCROSS and Orbital Neutron Water Abundance Estimates in Cabeus Crater

NASA Technical Reports Server (NTRS)

Elphic, Richard; Teodoro, Luis F.; Eke, Vincent R.; Paige, David A.; Siegler, Matthew A.; Colaprete, Anthony

2011-01-01

The Lunar Prospector Neutron Spectrometer (LPNS) first revealed Cabeus crater (84.9 deg S, 35.5degW) as having the highest inferred hydrogen on the Moon. Because of the broad LPNS footprint (approximately 40 km FWHM), the apparent peak water-equivalent hydrogen (WEH) concentration is only approximately 0.25 wt%, but could be much higher in smaller areas than the spectrometer footprint. Earlier image reconstruction work suggested that areas within permanent shadow have abundances approximately 1 wt% WEH. However, the LCROSS impact yielded total water estimates, ice plus vapor, of between 3 and 10 wt%. The large disagreement between LCROSS and apparent orbital values imply that either the ice is buried, by perhaps as much as 50 to 100 cm; or the ice distribution within Cabeus is spatially inhomogeneous, or both. Modeling reveals that the areal extent of a "shallow permafrost zone" is far greater than the area of permanent shadow. Ice can be virtually stable for billions of years within a few tens of centimeters of the surface in these areas. However, the LCROSS impact took place in an area of permanent shadow. If stably-trapped volatiles can be found in locales that receive occasional, oblique sunlight, landed missions may target these sites and eventual resource exploitation may be done more easily. Are orbital neutron data consistent with areally-extensive, volatile-rich cold traps? Orbital epithermal neutron data over the northern half of Cabeus (near the LCROSS impact site) are consistent with 0.2 wt% WEH or less in the "permafrost zone" near the crater. On the other hand, pixon reconstructions that confine the hydrogen enhancements to permanent shadow result in higher abundance estimates -- around 1 wt% if homogeneously mixed. But if the PSR abundance is increased to 10 wt%, consistent with the sum of all H-bearing compounds seen by LCROSS, a much larger-than-observed reduction in neutron count rate would be seen from orbit. It is likely that volatiles are

Measuring groundwater-surface water interaction and its effect on wetland stream benthic productivity, Trout Lake watershed, northern Wisconsin, USA

USGS Publications Warehouse

Hunt, R.J.; Strand, M.; Walker, J.F.

2006-01-01

Measurements of groundwater-surface water exchange at three wetland stream sites were related to patterns in benthic productivity as part of the US Geological Survey's Northern Temperate Lakes-Water, Energy and Biogeochemical Budgets (NTL-WEBB) project. The three sites included one high groundwater discharge (HGD) site, one weak groundwater discharge (WGD) site, and one groundwater recharge (GR) site. Large upward vertical gradients at the HGD site were associated with smallest variation in head below the stream and fewest gradient reversals between the stream and the groundwater beneath the stream, and the stream and the adjacent streambank. The WGD site had the highest number of gradient reversals reflecting the average condition being closest to zero vertical gradient. The duration of groundwater discharge events was related to the amount of discharge, where the HGD site had the longest strong-gradient durations for both horizontal and vertical groundwater flow. Strong groundwater discharge also controlled transient temperature and chemical hyporheic conditions by limiting the infiltration of surface water. Groundwater-surface water interactions were related to highly significant patterns in benthic invertebrate abundance, taxonomic richness, and periphyton respiration. The HGD site abundance was 35% greater than in the WGD site and 53% greater than the GR site; richness and periphyton respiration were also significantly greater (p???0.001, 31 and 44%, respectively) in the HGD site than in the GR site. The WGD site had greater abundance (27%), richness (19%) and periphyton respiration (39%) than the GR site. This work suggests groundwater-surface water interactions can strongly influence benthic productivity, thus emphasizing the importance of quantitative hydrology for management of wetland-stream ecosystems in the northern temperate regions. ?? 2005 Elsevier B.V. All rights reserved.

Surface freezing of water.

PubMed

Pérez-Díaz, J L; Álvarez-Valenzuela, M A; Rodríguez-Celis, F

2016-01-01

Freezing, melting, evaporation and condensation of water are essential ingredients for climate and eventually life on Earth. In the present work, we show how surface freezing of supercooled water in an open container is conditioned and triggered-exclusively-by humidity in air. Additionally, a change of phase is demonstrated to be triggered on the water surface forming surface ice crystals prior to freezing of bulk. The symmetry of the surface crystal, as well as the freezing point, depend on humidity, presenting at least three different types of surface crystals. Humidity triggers surface freezing as soon as it overpasses a defined value for a given temperature, generating a plurality of nucleation nodes. An evidence of simultaneous nucleation of surface ice crystals is also provided.

Phylogeography and pigment type diversity of Synechococcus cyanobacteria in surface waters of the northwestern pacific ocean.

PubMed

Xia, Xiaomin; Partensky, Frédéric; Garczarek, Laurence; Suzuki, Koji; Guo, Cui; Yan Cheung, Shun; Liu, Hongbin

2017-01-01

The widespread unicellular cyanobacteria Synechococcus are major contributors to global marine primary production. Here, we report their abundance, phylogenetic diversity (as assessed using the RNA polymerase gamma subunit gene rpoC1) and pigment diversity (as indirectly assessed using the laterally transferred cpeBA genes, encoding phycoerythrin-I) in surface waters of the northwestern Pacific Ocean, sampled over nine distinct cruises (2008-2015). Abundance of Synechococcus was low in the subarctic ocean and South China Sea, intermediate in the western subtropical Pacific Ocean, and the highest in the Japan and East China seas. Clades I and II were by far the most abundant Synechococcus lineages, the former dominating in temperate cold waters and the latter in (sub)tropical waters. Clades III and VI were also fairly abundant in warm waters, but with a narrower distribution than clade II. One type of chromatic acclimater (3dA) largely dominated the Synechococcus communities in the subarctic ocean, while another (3dB) and/or cells with a fixed high phycourobilin to phycoerythrobilin ratio (pigment type 3c) predominated at mid and low latitudes. Altogether, our results suggest that the variety of pigment content found in most Synechococcus clades considerably extends the niches that they can colonize and therefore the whole genus habitat. © 2016 Society for Applied Microbiology and John Wiley & Sons Ltd.

Hemispheric asymmetry in martian seasonal surface water ice from MGS TES

NASA Astrophysics Data System (ADS)

Bapst, Jonathan; Bandfield, Joshua L.; Wood, Stephen E.

2015-11-01

The Mars Global Surveyor (MGS) Thermal Emission Spectrometer (TES) visible/near-infrared and thermal infrared bolometers measured planetary broadband albedo and temperature for more than three Mars years. As seasons progress on Mars, surface temperatures may fall below the frost point of volatiles in the atmosphere (namely, carbon dioxide and water). Systematic mapping of the spatial and temporal occurrence of these volatiles in the martian atmosphere, on the surface, and in the subsurface has shown their importance in understanding the climate of Mars. We examine TES daytime albedo, temperature, and atmospheric opacity data to map the latitudinal and temporal occurrence of seasonal surface water frost on Mars. We expand on previous work by looking at the behavior of water frost over the entire martian year, made possible with comprehensive, multi-year data. Interpretations of frost are based on albedo changes and the corresponding daytime temperature range. Data is considered consistent with water frost when there are significant albedo increases (>0.05 relative to frost-free seasons) and the observed temperatures are ∼170-200 K. We argue the presence of extensive water frost in the northern hemisphere, extending from the pole to ∼40°N, following seasonal temperature trends. In the north, water frost first appears near the pole at Ls = ∼160° and is last observed at Ls = ∼90°. Extensive water frost is less evident in southern hemisphere data, though both hemispheres show data that are consistent with the presence of a water ice annulus during seasonal cap retreat. Hemispherical asymmetry in the occurrence of seasonal water frost is due in part to the lower (∼40%) atmospheric water vapor abundances observed in the southern hemisphere. Our results are consistent with net transport of water vapor to the northern hemisphere. The deposition and sublimation of seasonal water frost may significantly increase the near-surface water vapor density that could

Abundance and physiology of dominant soft corals linked to water quality in Jakarta Bay, Indonesia

PubMed Central

Januar, Indra; Wild, Christian; Kunzmann, Andreas

2016-01-01

Declining water quality is one of the main reasons of coral reef degradation in the Thousand Islands off the megacity Jakarta, Indonesia. Shifts in benthic community composition to higher soft coral abundances have been reported for many degraded reefs throughout the Indo-Pacific. However, it is not clear to what extent soft coral abundance and physiology are influenced by water quality. In this study, live benthic cover and water quality (i.e. dissolved inorganic nutrients (DIN), turbidity (NTU), and sedimentation) were assessed at three sites (< 20 km north of Jakarta) in Jakarta Bay (JB) and five sites along the outer Thousand Islands (20–60 km north of Jakarta). This was supplemented by measurements of photosynthetic yield and, for the first time, respiratory electron transport system (ETS) activity of two dominant soft coral genera, Sarcophyton spp. and Nephthea spp. Findings revealed highly eutrophic water conditions in JB compared to the outer Thousand Islands, with 44% higher DIN load (7.65 μM/L), 67% higher NTU (1.49 NTU) and 47% higher sedimentation rate (30.4 g m−2 d−1). Soft corals were the dominant type of coral cover within the bay (2.4% hard and 12.8% soft coral cover) compared to the outer Thousand Islands (28.3% hard and 6.9% soft coral cover). Soft coral abundances, photosynthetic yield, and ETS activity were highly correlated with key water quality parameters, particularly DIN and sedimentation rates. The findings suggest water quality controls the relative abundance and physiology of dominant soft corals in JB and may thus contribute to phase shifts from hard to soft coral dominance, highlighting the need to better manage water quality in order to prevent or reverse phase shifts. PMID:27904802

The abundance properties of nearby late-type galaxies. II. The relation between abundance distributions and surface brightness profiles

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

Pilyugin, L. S.; Grebel, E. K.; Zinchenko, I. A.

2014-12-01

The relations between oxygen abundance and disk surface brightness (OH–SB relation) in the infrared W1 band are examined for nearby late-type galaxies. The oxygen abundances were presented in Paper I. The photometric characteristics of the disks are inferred here using photometric maps from the literature through bulge-disk decomposition. We find evidence that the OH–SB relation is not unique but depends on the galactocentric distance r (taken as a fraction of the optical radius R{sub 25}) and on the properties of a galaxy: the disk scale length h and the morphological T-type. We suggest a general, four-dimensional OH–SB relation with themore » values r, h, and T as parameters. The parametric OH–SB relation reproduces the observed data better than a simple, one-parameter relation; the deviations resulting when using our parametric relation are smaller by a factor of ∼1.4 than that of the simple relation. The influence of the parameters on the OH–SB relation varies with galactocentric distance. The influence of the T-type on the OH–SB relation is negligible at the centers of galaxies and increases with galactocentric distance. In contrast, the influence of the disk scale length on the OH–SB relation is at a maximum at the centers of galaxies and decreases with galactocentric distance, disappearing at the optical edges of galaxies. Two-dimensional relations can be used to reproduce the observed data at the optical edges of the disks and at the centers of the disks. The disk scale length should be used as a second parameter in the OH–SB relation at the center of the disk while the morphological T-type should be used as a second parameter in the relation at optical edge of the disk. The relations between oxygen abundance and disk surface brightness in the optical B and infrared K bands at the center of the disk and at optical edge of the disk are also considered. The general properties of the abundance–surface brightness relations are similar for

Mineralogic control on abundance and diversity of surface-adherent microbial communities

USGS Publications Warehouse

Mauck, Brena S.; Roberts, Jennifer A.

2007-01-01

In this study, we investigated the role of mineral-bound P and Fe in defining microbial abundance and diversity in a carbon-rich groundwater. Field colonization experiments of initially sterile mineral surfaces were combined with community structure characterization of the attached microbial population. Silicate minerals containing varying concentrations of P (∼1000 ppm P) and Fe (∼4 wt % Fe 2 O3), goethite (FeOOH), and apatite [Ca5(PO4)3(OH)] were incubated for 14 months in three biogeochemically distinct zones within a petroleum-contaminated aquifer. Phospholipid fatty acid analysis of incubated mineral surfaces and groundwater was used as a measure of microbial community structure and biomass. Microbial biomass on minerals exhibited distinct trends as a function of mineralogy depending on the environment of incubation. In the carbon-rich, aerobic groundwater attached biomass did not correlate to the P- or Fe- content of the mineral. In the methanogenic groundwater, however, biomass was most abundant on P-containing minerals. Similarly, in the Fe-reducing groundwater a correlation between Fe-content and biomass was observed. The community structure of the mineral-adherent microbial population was compared to the native groundwater community. These two populations were significantly different regardless of mineralogy, suggesting differentiation of the planktonic community through attachment, growth, and death of colonizing cells. Biomarkers specific for dissimilatory Fe-reducing bacteria native to the aquifer were identified only on Fe-containing minerals in the Fe-reducing groundwater. These results demonstrate that the trace nutrient content of minerals affects both the abundance and diversity of surface-adherent microbial communities. This behavior may be a means to access limiting nutrients from the mineral, creating a niche for a particular microbial population. These results suggest that heterogeneity of microbial populations and their associated

Weakly bound water structure, bond valence saturation and water dynamics at the goethite (100) surface/aqueous interface: ab initio dynamical simulations.

PubMed

Chen, Ying; Bylaska, Eric J; Weare, John H

2017-03-31

Many important geochemical and biogeochemical reactions occur in the mineral/formation water interface of the highly abundant mineral, goethite [α-Fe(OOH)]. Ab initio molecular dynamics (AIMD) simulations of the goethite α-FeOOH (100) surface and the structure, water bond formation and dynamics of water molecules in the mineral/aqueous interface are presented. Several exchange correlation functionals were employed (PBE96, PBE96 + Grimme, and PBE0) in the simulations of a (3 × 2) goethite surface with 65 absorbed water molecules in a 3D-periodic supercell (a = 30 Å, FeOOH slab ~12 Å thick, solvation layer ~18 Å thick). The lowest energy goethite (100) surface termination model was determined to have an exposed surface Fe 3+ that was loosely capped by a water molecule and a shared hydroxide with a neighboring surface Fe 3+ . The water molecules capping surface Fe 3+ ions were found to be loosely bound at all DFT levels with and without Grimme corrections, indicative that each surface Fe 3+ was coordinated with only five neighbors. These long bonds were supported by bond valence theory calculations, which showed that the bond valence of the surface Fe 3+ was saturated and surface has a neutral charge. The polarization of the water layer adjacent to the surface was found to be small and affected only the nearest water. Analysis by density difference plots and localized Boys orbitals identified three types of water molecules: those loosely bound to the surface Fe 3+ , those hydrogen bonded to the surface hydroxyl, and bulk water with tetrahedral coordination. Boys orbital analysis showed that the spin down lone pair orbital of the weakly absorbed water interact more strongly with the spin up Fe 3+ ion. These weakly bound surface water molecules were found to rapidly exchange with the second water layer (~0.025 exchanges/ps) using a dissociative mechanism. Water molecules adjacent to the surface were found to only weakly interact with the surface and as a

Surface Water in Hawaii

USGS Publications Warehouse

Oki, Delwyn S.

2003-01-01

Surface water in Hawaii is a valued resource as well as a potential threat to human lives and property. The surface-water resources of Hawaii are of significant economic, ecologic, cultural, and aesthetic importance. Streams supply more than 50 percent of the irrigation water in Hawaii, and although streams supply only a few percent of the drinking water statewide, surface water is the main source of drinking water in some places. Streams also are a source of hydroelectric power, provide important riparian and instream habitats for many unique native species, support traditional and customary Hawaiian gathering rights and the practice of taro cultivation, and possess valued aesthetic qualities. Streams affect the physical, chemical, and aesthetic quality of receiving waters, such as estuaries, bays, and nearshore waters, which are critical to the tourism-based economy of the islands. Streams in Hawaii pose a danger because of their flashy nature; a stream's stage, or water level, can rise several feet in less than an hour during periods of intense rainfall. Streams in Hawaii are flashy because rainfall is intense, drainage basins are small, basins and streams are steep, and channel storage is limited. Streamflow generated during periods of heavy rainfall has led to loss of property and human lives in Hawaii. Most Hawaiian streams originate in the mountainous interiors of the islands and terminate at the coast. Streams are significant sculptors of the Hawaiian landscape because of the erosive power of the water they convey. In geologically young areas, such as much of the southern part of the island of Hawaii, well-defined stream channels have not developed because the permeability of the surface rocks generally is so high that rainfall infiltrates before flowing for significant distances on the surface. In geologically older areas that have received significant rainfall, streams and mass wasting have carved out large valleys.

Space-Confined Earth-Abundant Bifunctional Electrocatalyst for High-Efficiency Water Splitting.

PubMed

Tang, Yanqun; Fang, Xiaoyu; Zhang, Xin; Fernandes, Gina; Yan, Yong; Yan, Dongpeng; Xiang, Xu; He, Jing

2017-10-25

Hydrogen generation from water splitting could be an alternative way to meet increasing energy demands while also balancing the impact of energy being supplied by fossil-based fuels. The efficacy of water splitting strongly depends on the performance of electrocatalysts. Herein, we report a unique space-confined earth-abundant electrocatalyst having the bifunctionality of simultaneous hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), leading to high-efficiency water splitting. Outperforming Pt/C or RuO 2 catalysts, this mesoscopic, space-confined, bifunctional configuration is constructed from a monolithic zeolitic imidazolate framework@layered double hydroxide (ZIF@LDH) precursor on Ni foam. Such a confinement leads to a high dispersion of ultrafine Co 3 O 4 nanoparticles within the N-doped carbon matrix by temperature-dependent calcination of the ZIF@LDH. We demonstrate that the OER has an overpotential of 318 mV at a current density of 10 mA cm -2 , while that of HER is -106 mV @ -10 mA cm -2 . The voltage applied to a two-electrode cell for overall water splitting is 1.59 V to achieve a stable current density of 10 mA cm -2 while using the monolithic catalyst as both the anode and the cathode. It is anticipated that our space-confined method, which focuses on earth-abundant elements with structural integrity, may provide a novel and economically sound strategy for practical energy conversion applications.

The Chemistry and Excitation of Water in Molecular Clouds

NASA Technical Reports Server (NTRS)

Hollenbach, David

2003-01-01

We model the chemistry and thermal balance of opaque molecular clouds exposed to an external flux of ultraviolet photons. We include the processes of gas phase and grain surface chemical reactions; in particular we examine closely the freezing of atoms and molecules onto grain surfaces and the desorption of molecules from grain surfaces as a function of depth into a molecular cloud. We find that on the surface of a molecular cloud the gas phase water abundances are low because of photodissociation, and the grain phase water (ice) abundance is low because of photodesorption of water from the grain surfaces. Deeper into the cloud, at A(sub v) less than or approximately 2-8 depending on the strength of the external ultraviolet flux, the gas phase water abundance increases with depth as the photodissociation rates decline due to dust attenuation of the ultraviolet field. However, beyond A(sub v) less than or approximately 2-8 the gas phase water abundance declines because the water freezes as water ice on the grains, and photodesorption is no longer effective in clearing the ice. A peak water abundance of about 10(exp -6) to 10(exp -7) occurs at about A(sub v) approximately 2-8, relatively independent of the gas density and the ultraviolet field. We show that such a model matches very closely the observations of the Submillimeter Wave Astronomical Satellite (SWAS), a NASA Small Explorer Mission. The model elucidates several mechanisms that have been recently invoked to understand gas phase chemistry in clouds, including-the freeze-out of molecules onto grain surface, the desorption of these molecules from the surfaces, and the abundance gradients of molecules as functions of depth into molecular clouds.

Sustaining dry surfaces under water

PubMed Central

Jones, Paul R.; Hao, Xiuqing; Cruz-Chu, Eduardo R.; Rykaczewski, Konrad; Nandy, Krishanu; Schutzius, Thomas M.; Varanasi, Kripa K.; Megaridis, Constantine M.; Walther, Jens H.; Koumoutsakos, Petros; Espinosa, Horacio D.; Patankar, Neelesh A.

2015-01-01

Rough surfaces immersed under water remain practically dry if the liquid-solid contact is on roughness peaks, while the roughness valleys are filled with gas. Mechanisms that prevent water from invading the valleys are well studied. However, to remain practically dry under water, additional mechanisms need consideration. This is because trapped gas (e.g. air) in the roughness valleys can dissolve into the water pool, leading to invasion. Additionally, water vapor can also occupy the roughness valleys of immersed surfaces. If water vapor condenses, that too leads to invasion. These effects have not been investigated, and are critically important to maintain surfaces dry under water. In this work, we identify the critical roughness scale, below which it is possible to sustain the vapor phase of water and/or trapped gases in roughness valleys – thus keeping the immersed surface dry. Theoretical predictions are consistent with molecular dynamics simulations and experiments. PMID:26282732

Effect of Environmental Factors on Cyanobacterial Abundance and Cyanotoxins Production in Natural and Drinking Water, Bangladesh.

PubMed

Affan, Abu; Khomavis, Hisham S; Al-Harbi, Salim Marzoog; Haque, Mahfuzul; Khan, Saleha

2015-02-01

Cyanobacterial blooms commonly appear during the summer months in ponds, lakes and reservoirs in Bangladesh. In these areas, fish mortality, odorous water and fish and human skin irritation and eye inflammation have been reported. The influence of physicochemical factors on the occurrence of cyanobacteria and its toxin levels were evaluated in natural and drinking water in Bangladesh. A highly sensitive immunosorbent assay was used to detect microcystins (MCs). Cyanobacteria were found in 22 of 23 samples and the dominant species were Microcystis aeruginosa, followed by Microcystisflosaquae, Anabeana crassa and Aphanizomenon flosaquae. Cyanobacterial abundance varied from 39 to 1315 x 10(3) cells mL(-1) in natural water and 31 to 49 x 10(3) cells mL(-1) in tap water. MC concentrations were 25-82300 pg mL(-1) with the highest value measured in the fish research pond, followed by Ishakha Lake. In tap water, MC concentrations ranged from 30-32 pg mL(-1). The correlation between nitrate-nitrogen (NO3-N) concentration and cyanobacterial cell abundance was R2 = 0.62 while that between cyanobacterial abundance and MC concentration was R2 = 0.98. The increased NO3-N from fish feed, organic manure, poultry and dairy farm waste and fertilizer from agricultural land eutrophicated the water bodies and triggered cyanobacterial bloom formation. The increased amount of cyanobacteria produced MCs, subsequently reducing the water quality.

Seasonal variation in composition and abundance of harmful dinoflagellates in Yemeni waters, southern Red Sea.

PubMed

Alkawri, Abdulsalam

2016-11-15

General abundance and species composition of a dinoflagellate community in Yemeni coastal waters of Al Salif (southern Red Sea) were studied with a view to understand the annual variations in particular the toxic species. Dinoflagellates were more abundant among phytoplankton. Thirty five dinoflagellate taxa were identified, among which 12 were reported as potentially toxic species. A significant change in seasonal abundance was recorded with the maximum (2.27∗10 6 cellsl -1 ) in May, and the minimum (2.50∗10 2 cellsl -1 ) recorded in January. Kryptoperidinium foliaceum, which was reported for the first time from the Red Sea, was the most abundant species with a maximum in May 2013 (2.26∗10 6 cellsl -1 ). Spearman's rank correlation analysis indicates that, total harmful dinoflagellate cells, K. foliaceum, Prorocentrum gracile and Prorocentrum micans were significantly correlated with temperature. This study suggests that Yemeni waters should be monitored to investigate harmful species and to identify areas and seasons at higher risk. Copyright © 2016 Elsevier Ltd. All rights reserved.

Seasonal and interannual variations in coccolithophore abundance off Terceira Island, Azores (Central North Atlantic)

NASA Astrophysics Data System (ADS)

Narciso, Áurea; Gallo, Francesca; Valente, André; Cachão, Mário; Cros, Lluïsa; Azevedo, Eduardo B.; e Ramos, Joana Barcelos

2016-04-01

In order to characterize the natural coccolithophore community occurring offshore Azores and to determine their annual and interannual patterns, monthly samples were collected, from September 2010 to December 2014, in the photic zone off Terceira Island. The present study revealed a clear seasonal distribution and a considerable interannual variability of the living coccolithophore community. The highest coccolithophore abundances were observed during spring and winter months, especially due to the smaller species Emiliania huxleyi and Gephyrocapsa ericsonii. In fact, the highest biomass period was registered during April 2011, associated with enhanced abundance of the overcalcified morphotype of E. huxleyi, which was possibly influenced by subpolar waters and subsequent upwelling conditions. The highest abundances of Gephyrocapsa muellerae were recorded during June 2011 and 2014, indicating that this species characterizes the transition between the period of maximum productivity and the subsequent smoother environmental conditions, the first and the later stages of the phytoplankton succession described by Margalef, respectively. During summer to early fall, a gradual decrease of the overall coccolithophore abundance was observed, while the species richness (Margalef diversity index) increased. A subtropical coccolithophore assemblage mainly composed by Umbellosphaera tenuis, Syracosphaera spp., Discosphaera tubifera, Rhabdosphaera clavigera and Coronosphaera mediterranea indicated the presence of surface warmer waters accompanied by reduced mixing and low nutrients concentration. During late fall to winter, the coccolithophore abundance increased again with a concomitant reduction in species diversity. This is potentially linked to low sea surface temperatures, moderate nutrients concentration and surface mixed layer deepening. During 2011, colder and productive waters led to an increase in the total coccolithophore abundances. On contrary, during 2012

Species, Abundance and Function of Ammonia-oxidizing Archaea in Inland Waters across China

NASA Astrophysics Data System (ADS)

Zhou, Leiliu; Wang, Shanyun; Zou, Yuxuan; Xia, Chao; Zhu, Guibing

2015-11-01

Ammonia oxidation is the first step in nitrification and was thought to be performed solely by specialized bacteria. The discovery of ammonia-oxidizing archaea (AOA) changed this view. We examined the large scale and spatio-temporal occurrence, abundance and role of AOA throughout Chinese inland waters (n = 28). Molecular survey showed that AOA was ubiquitous in inland waters. The existence of AOA in extreme acidic, alkaline, hot, cold, eutrophic and oligotrophic environments expanded the tolerance limits of AOA, especially their known temperature tolerance to -25 °C, and substrate load to 42.04 mM. There were spatio-temporal divergences of AOA community structure in inland waters, and the diversity of AOA in inland water ecosystems was high with 34 observed species-level operational taxonomic units (OTUs; based on a 15% cutoff) distributed widely in group I.1b, I.1a, and I.1a-associated. The abundance of AOA was quite high (8.5 × 104 to 8.5 × 109 copies g-1), and AOA outnumbered ammonia-oxidizing bacteria (AOB) in the inland waters where little human activities were involved. On the whole AOB predominate the ammonia oxidation rate over AOA in inland water ecosystems, and AOA play an indispensable role in global nitrogen cycle considering that AOA occupy a broader habitat range than AOB, especially in extreme environments.

Effects of High Hydrostatic Pressure on Coastal Bacterial Community Abundance and Diversity

PubMed Central

Marietou, Angeliki

2014-01-01

Hydrostatic pressure is an important parameter influencing the distribution of microbial life in the ocean. In this study, the response of marine bacterial populations from surface waters to pressures representative of those under deep-sea conditions was examined. Southern California coastal seawater collected 5 m below the sea surface was incubated in microcosms, using a range of temperatures (16 to 3°C) and hydrostatic pressure conditions (0.1 to 80 MPa). Cell abundance decreased in response to pressure, while diversity increased. The morphology of the community also changed with pressurization to a predominant morphotype of small cocci. The pressure-induced community changes included an increase in the relative abundance of Alphaproteobacteria, Gammaproteobacteria, Actinobacteria, and Flavobacteria largely at the expense of Epsilonproteobacteria. Culturable high-pressure-surviving bacteria were obtained and found to be phylogenetically similar to isolates from cold and/or deep-sea environments. These results provide novel insights into the response of surface water bacteria to changes in hydrostatic pressure. PMID:25063663

Structure and stability of pyrophyllite edge surfaces: Effect of temperature and water chemical potential

NASA Astrophysics Data System (ADS)

Kwon, Kideok D.; Newton, Aric G.

2016-10-01

The surfaces of clay minerals, which are abundant in atmospheric mineral dust, serve as an important medium to catalyze ice nucleation. The lateral edge surface of 2:1 clay minerals is postulated to be a potential site for ice nucleation. However, experimental investigations of the edge surface structure itself have been limited compared to the basal planes of clay minerals. Density functional theory (DFT) computational studies have provided insights into the pyrophyllite edge surface. Pyrophyllite is an ideal surrogate mineral for the edge surfaces of 2:1 clay minerals as it possesses no or little structural charge. Of the two most-common hydrated edge surfaces, the AC edge, (1 1 0) surface in the monoclinic polytype notation, is predicted to be more stable than the B edge, (0 1 0) surface. These stabilities, however, were determined based on the total energies calculated at 0 K and did not consider environmental effects such as temperature and humidity. In this study, atomistic thermodynamics based on periodic DFT electronic calculations was applied to examine the effects of environmental variables on the structure and thermodynamic stability of the common edge surfaces in equilibrium with bulk pyrophyllite and water vapor. We demonstrate that the temperature-dependent vibrational energy of sorbed water molecules at the edge surface is a significant component of the surface free energy and cannot be neglected when determining the surface stability of pyrophyllite. The surface free energies were calculated as a function of temperature from 240 to 600 K and water chemical potential corresponding to conditions from ultrahigh vacuum to the saturation vapor pressure of water. We show that at lower water chemical potentials (dry conditions), the AC and B edge surfaces possessed similar stabilities; at higher chemical potentials (humid conditions) the AC edge surface was more stable than the B edge surface. At high temperatures, both surfaces showed similar stabilities

New Earth-abundant Materials for Large-scale Solar Fuels Generation.

PubMed

Prabhakar, Rajiv Ramanujam; Cui, Wei; Tilley, S David

2018-05-30

The solar resource is immense, but the power density of light striking the Earth's surface is relatively dilute, necessitating large area solar conversion devices in order to harvest substantial amounts of power for renewable energy applications. In addition, energy storage is a key challenge for intermittent renewable resources such as solar and wind, which adds significant cost to these energies. As the majority of humanity's present-day energy consumption is based on fuels, an ideal solution is to generate renewable fuels from abundant resources such as sunlight and water. In this account, we detail our recent work towards generating highly efficient and stable Earth-abundant semiconducting materials for solar water splitting to generate renewable hydrogen fuel.

Field Techniques for Estimating Water Fluxes Between Surface Water and Ground Water

USGS Publications Warehouse

Rosenberry, Donald O.; LaBaugh, James W.

2008-01-01

This report focuses on measuring the flow of water across the interface between surface water and ground water, rather than the hydrogeological or geochemical processes that occur at or near this interface. The methods, however, that use hydrogeological and geochemical evidence to quantify water fluxes are described herein. This material is presented as a guide for those who have to examine the interaction of surface water and ground water. The intent here is that both the overview of the many available methods and the in-depth presentation of specific methods will enable the reader to choose those study approaches that will best meet the requirements of the environments and processes they are investigating, as well as to recognize the merits of using more than one approach. This report is designed to make the reader aware of the breadth of approaches available for the study of the exchange between surface and ground water. To accomplish this, the report is divided into four chapters. Chapter 1 describes many well-documented approaches for defining the flow between surface and ground waters. Subsequent chapters provide an in-depth presentation of particular methods. Chapter 2 focuses on three of the most commonly used methods to either calculate or directly measure flow of water between surface-water bodies and the ground-water domain: (1) measurement of water levels in well networks in combination with measurement of water level in nearby surface water to determine water-level gradients and flow; (2) use of portable piezometers (wells) or hydraulic potentiomanometers to measure hydraulic gradients; and (3) use of seepage meters to measure flow directly. Chapter 3 focuses on describing the techniques involved in conducting water-tracer tests using fluorescent dyes, a method commonly used in the hydrogeologic investigation and characterization of karst aquifers, and in the study of water fluxes in karst terranes. Chapter 4 focuses on heat as a tracer in hydrological

Differential contributions of archaeal ammonia oxidizer ecotypes to nitrification in coastal surface waters

PubMed Central

Smith, Jason M; Casciotti, Karen L; Chavez, Francisco P; Francis, Christopher A

2014-01-01

The occurrence of nitrification in the oceanic water column has implications extending from local effects on the structure and activity of phytoplankton communities to broader impacts on the speciation of nitrogenous nutrients and production of nitrous oxide. The ammonia-oxidizing archaea, responsible for carrying out the majority of nitrification in the sea, are present in the marine water column as two taxonomically distinct groups. Water column group A (WCA) organisms are detected at all depths, whereas Water column group B (WCB) are present primarily below the photic zone. An open question in marine biogeochemistry is whether the taxonomic definition of WCA and WCB organisms and their observed distributions correspond to distinct ecological and biogeochemical niches. We used the natural gradients in physicochemical and biological properties that upwelling establishes in surface waters to study their roles in nitrification, and how their activity—ascertained from quantification of ecotype-specific ammonia monooxygenase (amoA) genes and transcripts—varies in response to environmental fluctuations. Our results indicate a role for both ecotypes in nitrification in Monterey Bay surface waters. However, their respective contributions vary, due to their different sensitivities to surface water conditions. WCA organisms exhibited a remarkably consistent level of activity and their contribution to nitrification appears to be related to community size. WCB activity was less consistent and primarily constrained to colder, high nutrient and low chlorophyll waters. Overall, the results of our characterization yielded a strong, potentially predictive, relationship between archaeal amoA gene abundance and the rate of nitrification. PMID:24553472

Low rates of nitrogen fixation in eastern tropical South Pacific surface waters

PubMed Central

Knapp, Angela N.; Casciotti, Karen L.; Berelson, William M.; Prokopenko, Maria G.; Capone, Douglas G.

2016-01-01

An extensive region of the Eastern Tropical South Pacific (ETSP) Ocean has surface waters that are nitrate-poor yet phosphate-rich. It has been proposed that this distribution of surface nutrients provides a geochemical niche favorable for N2 fixation, the primary source of nitrogen to the ocean. Here, we present results from two cruises to the ETSP where rates of N2 fixation and its contribution to export production were determined with a suite of geochemical and biological measurements. N2 fixation was only detectable using nitrogen isotopic mass balances at two of six stations, and rates ranged from 0 to 23 µmol N m−2 d−1 based on sediment trap fluxes. Whereas the fractional importance of N2 fixation did not change, the N2-fixation rates at these two stations were several-fold higher when scaled to other productivity metrics. Regardless of the choice of productivity metric these N2-fixation rates are low compared with other oligotrophic locations, and the nitrogen isotope budgets indicate that N2 fixation supports no more than 20% of export production regionally. Although euphotic zone-integrated short-term N2-fixation rates were higher, up to 100 µmol N m−2 d−1, and detected N2 fixation at all six stations, studies of nitrogenase gene abundance and expression from the same cruises align with the geochemical data and together indicate that N2 fixation is a minor source of new nitrogen to surface waters of the ETSP. This finding is consistent with the hypothesis that, despite a relative abundance of phosphate, iron may limit N2 fixation in the ETSP. PMID:26976587

Microplastics in Arctic polar waters: the first reported values of particles in surface and sub-surface samples

PubMed Central

Lusher, Amy L.; Tirelli, Valentina; O’Connor, Ian; Officer, Rick

2015-01-01

Plastic, as a form of marine litter, is found in varying quantities and sizes around the globe from surface waters to deep-sea sediments. Identifying patterns of microplastic distribution will benefit an understanding of the scale of their potential effect on the environment and organisms. As sea ice extent is reducing in the Arctic, heightened shipping and fishing activity may increase marine pollution in the area. Microplastics may enter the region following ocean transport and local input, although baseline contamination measurements are still required. Here we present the first study of microplastics in Arctic waters, south and southwest of Svalbard, Norway. Microplastics were found in surface (top 16 cm) and sub-surface (6 m depth) samples using two independent techniques. Origins and pathways bringing microplastic to the Arctic remain unclear. Particle composition (95% fibres) suggests they may either result from the breakdown of larger items (transported over large distances by prevailing currents, or derived from local vessel activity), or input in sewage and wastewater from coastal areas. Concurrent observations of high zooplankton abundance suggest a high probability for marine biota to encounter microplastics and a potential for trophic interactions. Further research is required to understand the effects of microplastic-biota interaction within this productive environment. PMID:26446348

Microplastics in Arctic polar waters: the first reported values of particles in surface and sub-surface samples

NASA Astrophysics Data System (ADS)

Lusher, Amy L.; Tirelli, Valentina; O'Connor, Ian; Officer, Rick

2015-10-01

Plastic, as a form of marine litter, is found in varying quantities and sizes around the globe from surface waters to deep-sea sediments. Identifying patterns of microplastic distribution will benefit an understanding of the scale of their potential effect on the environment and organisms. As sea ice extent is reducing in the Arctic, heightened shipping and fishing activity may increase marine pollution in the area. Microplastics may enter the region following ocean transport and local input, although baseline contamination measurements are still required. Here we present the first study of microplastics in Arctic waters, south and southwest of Svalbard, Norway. Microplastics were found in surface (top 16 cm) and sub-surface (6 m depth) samples using two independent techniques. Origins and pathways bringing microplastic to the Arctic remain unclear. Particle composition (95% fibres) suggests they may either result from the breakdown of larger items (transported over large distances by prevailing currents, or derived from local vessel activity), or input in sewage and wastewater from coastal areas. Concurrent observations of high zooplankton abundance suggest a high probability for marine biota to encounter microplastics and a potential for trophic interactions. Further research is required to understand the effects of microplastic-biota interaction within this productive environment.

Microplastics in Arctic polar waters: the first reported values of particles in surface and sub-surface samples.

PubMed

Lusher, Amy L; Tirelli, Valentina; O'Connor, Ian; Officer, Rick

2015-10-08

Plastic, as a form of marine litter, is found in varying quantities and sizes around the globe from surface waters to deep-sea sediments. Identifying patterns of microplastic distribution will benefit an understanding of the scale of their potential effect on the environment and organisms. As sea ice extent is reducing in the Arctic, heightened shipping and fishing activity may increase marine pollution in the area. Microplastics may enter the region following ocean transport and local input, although baseline contamination measurements are still required. Here we present the first study of microplastics in Arctic waters, south and southwest of Svalbard, Norway. Microplastics were found in surface (top 16 cm) and sub-surface (6 m depth) samples using two independent techniques. Origins and pathways bringing microplastic to the Arctic remain unclear. Particle composition (95% fibres) suggests they may either result from the breakdown of larger items (transported over large distances by prevailing currents, or derived from local vessel activity), or input in sewage and wastewater from coastal areas. Concurrent observations of high zooplankton abundance suggest a high probability for marine biota to encounter microplastics and a potential for trophic interactions. Further research is required to understand the effects of microplastic-biota interaction within this productive environment.

Species, Abundance and Function of Ammonia-oxidizing Archaea in Inland Waters across China

PubMed Central

Zhou, Leiliu; Wang, Shanyun; Zou, Yuxuan; Xia, Chao; Zhu, Guibing

2015-01-01

Ammonia oxidation is the first step in nitrification and was thought to be performed solely by specialized bacteria. The discovery of ammonia-oxidizing archaea (AOA) changed this view. We examined the large scale and spatio-temporal occurrence, abundance and role of AOA throughout Chinese inland waters (n = 28). Molecular survey showed that AOA was ubiquitous in inland waters. The existence of AOA in extreme acidic, alkaline, hot, cold, eutrophic and oligotrophic environments expanded the tolerance limits of AOA, especially their known temperature tolerance to −25 °C, and substrate load to 42.04 mM. There were spatio-temporal divergences of AOA community structure in inland waters, and the diversity of AOA in inland water ecosystems was high with 34 observed species-level operational taxonomic units (OTUs; based on a 15% cutoff) distributed widely in group I.1b, I.1a, and I.1a-associated. The abundance of AOA was quite high (8.5 × 104 to 8.5 × 109 copies g−1), and AOA outnumbered ammonia-oxidizing bacteria (AOB) in the inland waters where little human activities were involved. On the whole AOB predominate the ammonia oxidation rate over AOA in inland water ecosystems, and AOA play an indispensable role in global nitrogen cycle considering that AOA occupy a broader habitat range than AOB, especially in extreme environments. PMID:26522086

Surface Water Records of Colorado

USGS Publications Warehouse

U.S. Geological Survey, Water Resources Division

1962-01-01

The surface-water records for the 1962 water year for gaging stations and miscellaneous sites within the State of Colorado are given in this report. For convenience there are also included records for a few pertinent gaging stations in bordering States. The records were collected and computed by the Water Resources Division of the U.S. Geological Survey, under the direction of J. W. Odell, district engineer, Surface Water Branch.

Modeling species richness and abundance of phytoplankton and zooplankton in radioactively contaminated water bodies.

PubMed

Shuryak, Igor

2018-06-05

Water bodies polluted by the Mayak nuclear plant in Russia provide valuable information on multi-generation effects of radioactive contamination on freshwater organisms. For example, lake Karachay was probably the most radioactive lake in the world: its water contained ∼2 × 10 7 Bq/L of radionuclides and estimated dose rates to plankton exceeded 5 Gy/h. We performed quantitative modeling of radiation effects on phytoplankton and zooplankton species richness and abundance in Mayak-contaminated water bodies. Due to collinearity between radioactive contamination, water body size and salinity, we combined these variables into one (called HabitatFactors). We employed a customized machine learning approach, where synthetic noise variables acted as benchmarks of predictor performance. HabitatFactors was the only predictor that outperformed noise variables and, therefore, we used it for parametric modeling of plankton responses. Best-fit model predictions suggested 50% species richness reduction at HabitatFactors values corresponding to dose rates of 10 4 -10 5  μGy/h for phytoplankton, and 10 3 -10 4  μGy/h for zooplankton. Under conditions similar to those in lake Karachay, best-fit models predicted 81-98% species richness reductions for various taxa (Cyanobacteria, Bacillariophyta, Chlorophyta, Rotifera, Cladocera and Copepoda), ∼20-300-fold abundance reduction for total zooplankton, but no abundance reduction for phytoplankton. Rotifera was the only taxon whose fractional abundance increased with contamination level, reaching 100% in lake Karachay, but Rotifera species richness declined with contamination level, as in other taxa. Under severe radioactive and chemical contamination, one species of Cyanobacteria (Geitlerinema amphibium) dominated phytoplankton, and rotifers from the genus Brachionus dominated zooplankton. The modeling approaches proposed here are applicable to other radioecological data sets. The results provide quantitative information

Estimating Water Ice Abundance from Short-Wave Infrared Spectra of Drill Cuttings at Cryogenic Temperatures

NASA Technical Reports Server (NTRS)

Roush, Ted L.; Colaprete, Anthony; Kleinhenz, Julie; Cook, Amanda

2017-01-01

NASA's Resource Prospector (RP) mission intends to visit a lunar polar region to characterize the volatile distribution. Part of the RP payload, the Near-infrared Volatile Spectrometer System (NIRVSS) is a spectrometer operating from 1600-3400 nm that provides sensitivity to water ice, and other volatiles. For multiple years, the NIRVSS system has been incorporated into on-going RP payload testing in a cryogenic vacuum facility at Glenn Research Center. Soil tubes of lunar simulants, prepared with known amounts of water, are placed in the vacuum chamber and cooled to cryogenic temperatures (soil temperatures of 110-170 K) and placed under low vacuum (a few x 10(exp -6) Torr). During these tests NIRVSS continuously measures spectra of soil cuttings emplaced onto the surface by a drill. Real time processing of NIRVSS spectra produces two spectral parameters associated with water ice absorption features near 2000 and 3000 nm that can be used to inform decision making activities such as delivery of the soil to a sealable container. Post-test collection and analyses of the soils permit characterization the water content as a function of depth. These water content profiles exhibit the characteristics of a vacuum desiccation zone to depths of about 40 cm. Subsequent to completion of the tests, NIRVSS spectra are processed to produce two spectral parameters associated with water ice absorption features near 2000 and 3000 nm. These features can be evaluated as a function of time, and correlated with drill depth, and other measurements, throughout the drilling activities. Until now no effort was attempted to quantitatively relate these parameters to water abundance. This is the focus of our efforts to be presented.

Estimating Water Ice Abundance from Short-wave Infrared Spectra of Drill Cuttings at Cryogenic Temperatures

NASA Astrophysics Data System (ADS)

Roush, T. L.; Colaprete, A.; Kleinhenz, J.; Cook, A.

2017-12-01

NASA's Resource Prospector (RP) mission intends to visit a lunar polar region to characterize the volatile distribution. Part of the RP payload, the Near-infrared Volatile Spectrometer System (NIRVSS) is a spectrometer operating from 1600-3400 nm that provides sensitivity to water ice, and other volatiles. For multiple years, the NIRVSS system has been incorporated into on-going RP payload testing in a cryogenic vacuum facility at Glenn Research Center. Soil tubes of lunar simulants, prepared with known amounts of water, are placed in the vacuum chamber and cooled to cryogenic temperatures (soil temperatures of 110-170° K) and placed under low vacuum (a few x 10-6 Torr). During these tests NIRVSS continuously measures spectra of soil cuttings emplaced onto the surface by a drill. Real time processing of NIRVSS spectra produces two spectral parameters associated with water ice absorption features near 2000 and 3000 nm that can be used to inform decision-making activities such as delivery of the soil to a sealable container. Post-test collection and analyses of the soils permit characterization the water content as a function of depth. These water content profiles exhibit the characteristics of a vacuum desiccation zone to depths of about 40 cm. Subsequent to completion of the tests, NIRVSS spectra are processed to produce two spectral parameters associated with water ice absorption features near 2000 and 3000 nm. These features can be evaluated as a function of time, and correlated with drill depth, and other measurements, throughout the drilling activities. Until now no effort was attempted to quantitatively relate these parameters to water abundance. This is the focus of our efforts to be presented.

Linking species abundance distributions in numerical abundance and biomass through simple assumptions about community structure.

PubMed

Henderson, Peter A; Magurran, Anne E

2010-05-22

Species abundance distributions (SADs) are widely used as a tool for summarizing ecological communities but may have different shapes, depending on the currency used to measure species importance. We develop a simple plotting method that links SADs in the alternative currencies of numerical abundance and biomass and is underpinned by testable predictions about how organisms occupy physical space. When log numerical abundance is plotted against log biomass, the species lie within an approximately triangular region. Simple energetic and sampling constraints explain the triangular form. The dispersion of species within this triangle is the key to understanding why SADs of numerical abundance and biomass can differ. Given regular or random species dispersion, we can predict the shape of the SAD for both currencies under a variety of sampling regimes. We argue that this dispersion pattern will lie between regular and random for the following reasons. First, regular dispersion patterns will result if communities are comprised groups of organisms that use different components of the physical space (e.g. open water, the sea bed surface or rock crevices in a marine fish assemblage), and if the abundance of species in each of these spatial guilds is linked to the way individuals of varying size use the habitat. Second, temporal variation in abundance and sampling error will tend to randomize this regular pattern. Data from two intensively studied marine ecosystems offer empirical support for these predictions. Our approach also has application in environmental monitoring and the recognition of anthropogenic disturbance, which may change the shape of the triangular region by, for example, the loss of large body size top predators that occur at low abundance.

Linking species abundance distributions in numerical abundance and biomass through simple assumptions about community structure

PubMed Central

Henderson, Peter A.; Magurran, Anne E.

2010-01-01

Species abundance distributions (SADs) are widely used as a tool for summarizing ecological communities but may have different shapes, depending on the currency used to measure species importance. We develop a simple plotting method that links SADs in the alternative currencies of numerical abundance and biomass and is underpinned by testable predictions about how organisms occupy physical space. When log numerical abundance is plotted against log biomass, the species lie within an approximately triangular region. Simple energetic and sampling constraints explain the triangular form. The dispersion of species within this triangle is the key to understanding why SADs of numerical abundance and biomass can differ. Given regular or random species dispersion, we can predict the shape of the SAD for both currencies under a variety of sampling regimes. We argue that this dispersion pattern will lie between regular and random for the following reasons. First, regular dispersion patterns will result if communities are comprised groups of organisms that use different components of the physical space (e.g. open water, the sea bed surface or rock crevices in a marine fish assemblage), and if the abundance of species in each of these spatial guilds is linked to the way individuals of varying size use the habitat. Second, temporal variation in abundance and sampling error will tend to randomize this regular pattern. Data from two intensively studied marine ecosystems offer empirical support for these predictions. Our approach also has application in environmental monitoring and the recognition of anthropogenic disturbance, which may change the shape of the triangular region by, for example, the loss of large body size top predators that occur at low abundance. PMID:20071388

Links between type E botulism outbreaks, lake levels, and surface water temperatures in Lake Michigan, 1963-2008

USGS Publications Warehouse

Lafrancois, Brenda Moraska; Riley, Stephen C.; Blehert, David S.; Ballmann, Anne E.

2011-01-01

Relationships between large-scale environmental factors and the incidence of type E avian botulism outbreaks in Lake Michigan were examined from 1963 to 2008. Avian botulism outbreaks most frequently occurred in years with low mean annual water levels, and lake levels were significantly lower in outbreak years than in non-outbreak years. Mean surface water temperatures in northern Lake Michigan during the period when type E outbreaks tend to occur (July through September) were significantly higher in outbreak years than in non-outbreak years. Trends in fish populations did not strongly correlate with botulism outbreaks, although botulism outbreaks in the 1960s coincided with high alewife abundance, and recent botulism outbreaks coincided with rapidly increasing round goby abundance. Botulism outbreaks occurred cyclically, and the frequency of outbreaks did not increase over the period of record. Climate change scenarios for the Great Lakes predict lower water levels and warmer water temperatures. As a consequence, the frequency and magnitude of type E botulism outbreaks in the Great Lakes may increase.

Occurrence and Distribution of Organophosphate Flame Retardants/Plasticizers in Surface Waters, Tap Water, and Rainwater: Implications for Human Exposure.

PubMed

Kim, Un-Jung; Kannan, Kurunthachalam

2018-04-27

The occurrence and profiles of 14 triester organophosphate flame retardants (OPFRs) and plasticizers were investigated in surface water, tap water, rainwater, and seawater collected from New York State. In total, 150 samples collected from rivers ( n = 35), lakes ( n = 39), tap water ( n = 58), precipitation/rainwater ( n = 15), and seawater ( n = 3) were analyzed for 14 organophosphate esters (OPEs). An additional nine Hudson River water samples were collected periodically to delineate seasonal trends in OPE levels. The total concentrations of OPEs were found at part-per-trillion ranges, with average concentrations that ranged from 0.01 ng/L for tripropyl phosphate (TPP) in river water to 689 ng/L for tris(2-butoxyethyl)phosphate (TBOEP) in lake water. Tris(1-chloro-2-propyl)phosphate (TCIPP) was the most abundant compound among the investigated OPEs in all types of water. The concentrations of OPEs in river-, lake-, and rainwater were similar but >3 times higher than those found in tap water. Chlorinated alkyl OPFRs accounted for a major proportion of total concentrations. TCIPP, TBOEP, and triethyl phosphate (TEP) were found in >90% of the samples analyzed. Wet deposition fluxes for 14 OPFRs were estimated, on the basis of the concentrations measured in rainwater in Albany, New York, and the values were between 440 and 5250 ng/m 2 . Among several surface water bodies analyzed, samples from the Hudson River and Onondaga Lake contained elevated concentrations of OPEs. Estimated daily intake of OPEs via the ingestion of drinking water was up to 9.65 ng/kg body weight/day.

Implications of abundant hygroscopic minerals in the Martian regolith

NASA Technical Reports Server (NTRS)

Clark, B. C.

1978-01-01

Converging lines of evidence suggest that a significant portion of the Martian surface fines may consist of salts and smectite clays. Salts can form stoichiometric hydrates as well as eutectic solutions with depressed freezing points; clays contain bound water of constitution and adsorb significant quantities of water from the vapor phase. The formation of ice may be suppressed by these minerals in some regions on Mars, and their presence in abundance would imply important consequences for atmospheric and geologic processes and the prospects for exobiology.

The Influence of Heavy Metals and Water Parameters on the Composition and Abundance of Water Bugs (Insecta: Hemiptera) in the Kerian River Basin, Perak, Malaysia

PubMed Central

Ishadi, Nur Adibah Mohd; Rawi, Che Salmah Md; Ahmad, Abu Hassan; Abdul, Nurul Huda

2014-01-01

The hemipteran (Insecta) diversity in the upper part of the Kerian River Basin was low with only 8 families and 16 genera recorded at 4 study sites from 3 rivers. Water bug composition varied among sampling sites (Kruskal-Wallis χ 2 = 0.00, p<0.05) but was not affected by wet-dry seasons (Z = 0.00, p>0.05). All recorded water parameters were weakly associated with generic abundance but the biochemical oxygen demand (BOD), chemical oxygen demand (COD), Water Quality Index (WQI) and heavy metals (zinc and manganese) showed relatively strong positive or negative relations with hemipteran diversity and richness (H’ and R2). Within the ranges of measured water parameters, the WQI was negatively associated with hemipteran diversity and richness, implying the tolerance of the water bugs to the level of pollution encountered in the river basin. Based on its highest abundance and occurrence (ISI), Rhagovelia was the most important genus and along with Rheumatogonus and Paraplea, these genera were common at all study sites. In conclusion, habitat availability and suitability together with some environmental parameters influenced the abundance and composition of hemipterans in this river basin. PMID:27073600

CONNECTICUT SURFACE WATER QUALITY CLASSIFICATIONS

EPA Science Inventory

This is a 1:24,000-scale datalayer of Surface Water Quality Classifications for Connecticut. It is comprised of two 0Shapefiles with line and polygon features. Both Shapefiles must be used together with the Hydrography datalayer. The polygon Shapefile includes surface water qual...

Atmospheric aerosol deposition influences marine microbial communities in oligotrophic surface waters of the western Pacific Ocean

NASA Astrophysics Data System (ADS)

Maki, Teruya; Ishikawa, Akira; Mastunaga, Tomoki; Pointing, Stephen B.; Saito, Yuuki; Kasai, Tomoaki; Watanabe, Koichi; Aoki, Kazuma; Horiuchi, Amane; Lee, Kevin C.; Hasegawa, Hiroshi; Iwasaka, Yasunobu

2016-12-01

Atmospheric aerosols contain particulates that are deposited to oceanic surface waters. These can represent a major source of nutrients, trace metals, and organic compounds for the marine environment. The Japan Sea and the western Pacific Ocean are particularly affected by aerosols due to the transport of desert dust and industrially derived particulate matter with aerodynamic diameter less than 2.5 μm (PM2.5) from continental Asia. We hypothesized that supplementing seawater with aerosol particulates would lead to measurable changes in surface water nutrient composition as well as shifts in the marine microbial community. Shipboard experiments in the Pacific Ocean involved the recovery of oligotrophic oceanic surface water and subsequent supplementation with aerosol particulates obtained from the nearby coastal mountains, to simulate marine particulate input in this region. Initial increases in nitrates due to the addition of aerosol particulates were followed by a decrease correlated with the increase in phytoplankton biomass, which was composed largely of Bacillariophyta (diatoms), including Pseudo-nitzschia and Chaetoceros species. This shift was accompanied by changes in the bacterial community, with apparent increases in the relative abundance of heterotrophic Rhodobacteraceae and Colwelliaceae in aerosol particulate treated seawater. Our findings provide empirical evidence revealing the impact of aerosol particulates on oceanic surface water microbiology by alleviating nitrogen limitation in the organisms.

Molecular analysis of long-term biofilm formation on PVC and cast iron surfaces in drinking water distribution system.

PubMed

Liu, Ruyin; Zhu, Junge; Yu, Zhisheng; Joshi, DevRaj; Zhang, Hongxun; Lin, Wenfang; Yang, Min

2014-04-01

To understand the impacts of different plumbing materials on long-term biofilm formation in water supply system, we analyzed microbial community compositions in the bulk water and biofilms on faucets with two different materials-polyvinyl chloride (PVC) and cast iron, which have been frequently used for more than10 years. Pyrosequencing was employed to describe both bacterial and eukaryotic microbial compositions. Bacterial communities in the bulk water and biofilm samples were significantly different from each other. Specific bacterial populations colonized on the surface of different materials. Hyphomicrobia and corrosion associated bacteria, such as Acidithiobacillus spp., Aquabacterium spp., Limnobacter thiooxidans, and Thiocapsa spp., were the most dominant bacteria identified in the PVC and cast iron biofilms, respectively, suggesting that bacterial colonization on the material surfaces was selective. Mycobacteria and Legionella spp. were common potential pathogenic bacteria occurred in the biofilm samples, but their abundance was different in the two biofilm bacterial communities. In contrast, the biofilm samples showed more similar eukaryotic communities than the bulk water. Notably, potential pathogenic fungi, i.e., Aspergillus spp. and Candida parapsilosis, occurred in similar abundance in both biofilms. These results indicated that microbial community, especially bacterial composition was remarkably affected by the different pipe materials (PVC and cast iron). Copyright © 2014 The Research Centre for Eco-Environmental Sciences, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved.

Abundance and Distribution Characteristics of Microplastics in Surface Seawaters of the Incheon/Kyeonggi Coastal Region.

PubMed

Chae, Doo-Hyeon; Kim, In-Sung; Kim, Seung-Kyu; Song, Young Kyoung; Shim, Won Joon

2015-10-01

Microplastics in marine environments are of emerging concern due to their widespread distribution, their ingestion by various marine organisms, and their roles as a source and transfer vector of toxic chemicals. However, our understanding of their abundance and distribution characteristics in surface seawater (SSW) remains limited. We investigated microplastics in the surface microlayer (SML) and the SSW at 12 stations near-shore and offshore of the Korean west coast, Incheon/Kyeonggi region. Variation between stations, sampling media, and sampling methods were compared based on abundances, size distribution, and composition profiles of microsized synthetic polymer particles. The abundance of microplastics was greater in the SML (152,688 ± 92,384 particles/m(3)) than in SSW and showed a significant difference based on the sampling method for SSWs collected using a hand net (1602 ± 1274 particles/m(3)) and a zooplankton trawl net (0.19 ± 0.14 particles/m(3)). Ship paint particles (mostly alkyd resin polymer) accounted for the majority of microplastics detected in both SML and SSWs, and increased levels were observed around the voyage routes of large vessels. This indicates that polymers with marine-based origins become an important contributor to microplastics in coastal SSWs of this coastal region.

Analysis of cyanobacterial metabolites in surface and raw drinking waters reveals more than microcystin.

PubMed

Beversdorf, Lucas J; Rude, Kayla; Weirich, Chelsea A; Bartlett, Sarah L; Seaman, Mary; Kozik, Christine; Biese, Peter; Gosz, Timothy; Suha, Michael; Stempa, Christopher; Shaw, Christopher; Hedman, Curtis; Piatt, Joseph J; Miller, Todd R

2018-04-16

Freshwater cyanobacterial blooms are becoming increasingly problematic in regions that rely on surface waters for drinking water production. Microcystins (MCs) are toxic peptides produced by multiple cyanobacterial genera with a global occurrence. Cyanobacteria also produce a variety of other toxic and/or otherwise bioactive peptides (TBPs) that have gained less attention including cyanopeptolins (Cpts), anabaenopeptins (Apts), and microginins (Mgn). In this study, we compared temporal and spatial trends of four MCs (MCLR, MCRR, MCYR, MCLA), three Cpts (Cpt1020, Cpt1041, Cpt1007), two Apts (AptF, AptB), and Mgn690 in raw drinking water and at six surface water locations above these drinking water intakes in a eutrophic lake. All four MC congeners and five of six TBPs were detected in lake and raw drinking water. Across all samples, MCLR was the most frequently detected metabolite (100% of samples) followed by MCRR (97%) > Cpt1007 (74%) > MCYR (69%) > AptF (67%) > MCLA (61%) > AptB (54%) > Mgn690 (29%) and Cpt1041 (15%). Mean concentrations of MCs, Apts, and Cpts into two drinking water intakes were 3.9 ± 4.7, 0.14 ± 0.21, and 0.38 ± 0.92, respectively. Mean concentrations in surface water were significantly higher (p < 0.05) than in drinking water intakes for MCs but not for Cpts and Apts. Temporal trends in MCs, Cpts, and Apts in the two raw drinking water intakes were significantly correlated (p < 0.05) with measures of cell abundance (chlorophyll-a, Microcystis cell density), UV absorbance, and turbidity in surface water. This study expands current information about cyanobacterial TBPs that occur in lakes and that enter drinking water treatment plants and underscores the need to determine the fate of less studied cyanobacterial metabolites during drinking water treatment that may exacerbate toxicity of more well-known cyanobacterial toxins. Copyright © 2018 Elsevier Ltd. All rights reserved.

Thresholds in the response of free-floating plant abundance to variation in hydraulic connectivity, nutrients, and macrophyte abundance in a large floodplain river

USGS Publications Warehouse

Giblin, Shawn M.; Houser, Jeffrey N.; Sullivan, John F.; Langrehr, H.A.; Rogala, James T.; Campbell, Benjamin D.

2014-01-01

Duckweed and other free-floating plants (FFP) can form dense surface mats that affect ecosystem condition and processes, and can impair public use of aquatic resources. FFP obtain their nutrients from the water column, and the formation of dense FFP mats can be a consequence and indicator of river eutrophication. We conducted two complementary surveys of diverse aquatic areas of the Upper Mississippi River as an in situ approach for estimating thresholds in the response of FFP abundance to nutrient concentration and physical conditions in a large, floodplain river. Local regression analysis was used to estimate thresholds in the relations between FFP abundance and phosphorus (P) concentration (0.167 mg l−1L), nitrogen (N) concentration (0.808 mg l−1), water velocity (0.095 m s−1), and aquatic macrophyte abundance (65 % cover). FFP tissue concentrations suggested P limitation was more likely in spring, N limitation was more likely in late summer, and N limitation was most likely in backwaters with minimal hydraulic connection to the channel. The thresholds estimated here, along with observed patterns in nutrient limitation, provide river scientists and managers with criteria to consider when attempting to modify FFP abundance in off-channel areas of large river systems.

Partial oxidation of landfill leachate in supercritical water: Optimization by response surface methodology

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

Gong, Yanmeng; Wang, Shuzhong; Xu, Haidong

Highlights: • Partial oxidation of landfill leachate in supercritical water was investigated. • The process was optimized by Box–Behnken design and response surface methodology. • GY{sub H2}, TRE and CR could exhibit up to 14.32 mmol·gTOC{sup −1}, 82.54% and 94.56%. • Small amounts of oxidant can decrease the generation of tar and char. - Abstract: To achieve the maximum H{sub 2} yield (GY{sub H2}), TOC removal rate (TRE) and carbon recovery rate (CR), response surface methodology was applied to optimize the process parameters for supercritical water partial oxidation (SWPO) of landfill leachate in a batch reactor. Quadratic polynomial models formore » GY{sub H2}, CR and TRE were established with Box–Behnken design. GY{sub H2}, CR and TRE reached up to 14.32 mmol·gTOC{sup −1}, 82.54% and 94.56% under optimum conditions, respectively. TRE was invariably above 91.87%. In contrast, TC removal rate (TR) only changed from 8.76% to 32.98%. Furthermore, carbonate and bicarbonate were the most abundant carbonaceous substances in product, whereas CO{sub 2} and H{sub 2} were the most abundant gaseous products. As a product of nitrogen-containing organics, NH{sub 3} has an important effect on gas composition. The carbon balance cannot be reached duo to the formation of tar and char. CR increased with the increase of temperature and oxidation coefficient.« less

The paradoxical distribution of a shallow-rooted keystone species away from surface water, near the water-limited edge of its range in the Sonoran Desert: Seed-seedling conflicts

NASA Astrophysics Data System (ADS)

Drezner, Taly Dawn

2013-02-01

Species distributions reflect limiting factors, particularly near the margins of their range where density and abundance decrease as environmental factors decrease or increase to non-optimal conditions. I test whether the keystone saguaro cactus (Carnegiea gigantea), a shallow-rooted species, is indeed distributed disproportionately in areas of concentrated drainage (runnels) in a water-limited population. Carnegiea and a common nurse were sampled at a marginal site in and out of areas with concentrated surface water and chi-square analysis was used to determine the pattern of distribution. In this study I found that, surprisingly, near the hot, water-limited edge of their range, C. gigantea are found significantly less often in areas where more water would be available to them. For example, while only 20% of nurses were on interfluves, half of Carnegiea protégé were there. One possible explanation is that the subsequent redistribution of seeds by water away from preferred microsites may be important in shaping the final pattern of successful establishment. The shallow-rooted Carnegiea relies entirely on surface water for its moisture; it is thus paradoxical that the surface water so fundamentally essential to its survival throughout its life appears to hinder its establishment in precisely those sites where the greatest surface water would be available, particularly near the water-limited edge of its range.

Niche modelling of marsh plants based on occurrence and abundance data.

PubMed

Lou, Yanjing; Gao, Chuanyu; Pan, Yanwen; Xue, Zhenshan; Liu, Ying; Tang, Zhanhui; Jiang, Ming; Lu, Xianguo; Rydin, Håkan

2018-03-01

The information of species' response (optimum or critical limits along environmental gradients) is a key to understanding ecological questions and to design management plans. A large number of plots (762) from 70 transects of 13 wetland sites in Northeast China were sampled along flooding gradient from marsh to wet meadow. Species response (abundance and occurrence) to flooding were modelled with Generalized Additive Models for 21 dominant plant species. We found that 20 of 21 species showed a significant response to flooding for the occurrence and abundance models, and four types of response were found: monotonically increasing, monotonically decreasing, skewed unimodal and symmetric unimodal. The species with monotonically increasing response have the deepest flooding optimum and widest niche width, followed by those with unimodal curve, and the monotonically decreasing ones have the smallest values. The optima and niche width (whether based on occurrence or abundance models) both significantly correlated with the frequency, but not with mean abundance. Abundance models outperformed occurrence models based on goodness of fit. The abundance models predicted a rather sharp shift from dominance of helophytes (Carex pseudo-curaica and C. lasiocarpa) to wet meadow species (Calamagrostis angustifolia and Carex appendiculata) if water levels drop from about 10cm above soil surface to below the surface. The defined optima and niche width based on the abundance models can be applied to better instruct restoration management. Given the time required to collect abundance data, an efficient strategy could be to monitor occurrence in many plots and abundance in a subset of these. Copyright © 2017 Elsevier B.V. All rights reserved.

Modulators of heterogeneous protein surface water dynamics

NASA Astrophysics Data System (ADS)

Han, Songi

The hydration water that solvates proteins is a major factor in driving or enabling biological events, including protein-protein and protein-ligand interactions. We investigate the role of the protein surface in modulating the hydration water fluctuations on both the picosecond and nanosecond timescale with an emerging experimental NMR technique known as Overhauser Dynamic Nuclear Polarization (ODNP). We carry out site-specific ODNP measurements of the hydration water fluctuations along the surface of Chemotaxis Y (CheY), and correlate the measured fluctuations to hydropathic and topological properties of the CheY surface as derived from molecular dynamics (MD) simulation. Furthermore, we compare hydration water fluctuations measured on the CheY surface to that of other globular proteins, as well as intrinsically disordered proteins, peptides, and liposome surfaces to systematically test characteristic effects of the biomolecular surface on the hydration water dynamics. Our results suggest that the labile (ps) hydration water fluctuations are modulated by the chemical nature of the surface, while the bound (ns) water fluctuations are present on surfaces that feature a rough topology and chemical heterogeneity such as the surface of a folded and structured protein. In collaboration with: Ryan Barnes, Dept of Chemistry and Biochemistry, University of California Santa Barbara

Water surface capturing by image processing

USDA-ARS?s Scientific Manuscript database

An alternative means of measuring the water surface interface during laboratory experiments is processing a series of sequentially captured images. Image processing can provide a continuous, non-intrusive record of the water surface profile whose accuracy is not dependent on water depth. More trad...

Accurate experimental determination of the isotope effects on the triple point temperature of water. I. Dependence on the 2H abundance

NASA Astrophysics Data System (ADS)

Faghihi, V.; Peruzzi, A.; Aerts-Bijma, A. T.; Jansen, H. G.; Spriensma, J. J.; van Geel, J.; Meijer, H. A. J.

2015-12-01

Variation in the isotopic composition of water is one of the major contributors to uncertainty in the realization of the triple point of water (TPW). Although the dependence of the TPW on the isotopic composition of the water has been known for years, there is still a lack of a detailed and accurate experimental determination of the values for the correction constants. This paper is the first of two articles (Part I and Part II) that address quantification of isotope abundance effects on the triple point temperature of water. In this paper, we describe our experimental assessment of the 2H isotope effect. We manufactured five triple point cells with prepared water mixtures with a range of 2H isotopic abundances encompassing widely the natural abundance range, while the 18O and 17O isotopic abundance were kept approximately constant and the 18O  -  17O ratio was close to the Meijer-Li relationship for natural waters. The selected range of 2H isotopic abundances led to cells that realised TPW temperatures between approximately  -140 μK to  +2500 μK with respect to the TPW temperature as realized by VSMOW (Vienna Standard Mean Ocean Water). Our experiment led to determination of the value for the δ2H correction parameter of A2H  =  673 μK / (‰ deviation of δ2H from VSMOW) with a combined uncertainty of 4 μK (k  =  1, or 1σ).

Water Ice Abundance on Ceres

NASA Image and Video Library

2016-12-15

This frame from an animation shows dwarf planet Ceres overlaid with the concentration of hydrogen determined from data acquired by the gamma ray and neutron detector GRaND instrument aboard NASA Dawn spacecraft. The hydrogen is in the upper yard (or meter) of regolith, the loose surface material on Ceres. The color scale gives hydrogen content in water-equivalent units, which assumes all of the hydrogen is in the form of H2O. Blue indicates where hydrogen content is higher, near the poles, while red indicates lower content at lower latitudes. In reality, some of the hydrogen is in the form of water ice, while a portion of the hydrogen is in the form of hydrated minerals (such as OH, in serpentine group minerals). The color information is superimposed on shaded relief map for context. A second animation (Figure 2) compares the hydrogen content of Ceres' regolith with that of the giant asteroid Vesta, which Dawn orbited from 2011 to 2012. These data show Vesta is a much drier world, with a much lower percent of hydrogen in its regolith. Both maps were produced from data acquired by GRaND. Videos are available at http://photojournal.jpl.nasa.gov/catalog/PIA21081

Comparison of low-cost and engineered materials for phosphorus removal from organic-rich surface water.

PubMed

Boyer, Treavor H; Persaud, Amar; Banerjee, Poulomi; Palomino, Pedro

2011-10-15

Excess phosphorus (P) in lakes and rivers remains a major water quality problem on a global scale. As a result, new materials and innovative approaches to P remediation are required. Natural materials and waste byproduct materials from industrial processes have the potential to be effective materials for P removal from surface water. Advantages of natural and waste byproduct materials include their low-cost, abundant supply, and minimal preparation, especially compared with engineered materials, such as ion exchange resins and polymeric adsorbents. As a result, natural and waste byproduct materials are commonly referred to as low-cost materials. Despite the potential advantages of low-cost materials, there are critical gaps in knowledge that are preventing their effective use. In particular, there are limited data on the performance of low-cost materials in surface waters that have high concentrations of natural organic matter (NOM), and there are no systematic studies that track the changes in water chemistry following treatment with low-cost materials or compare their performance with engineered materials. Accordingly, the goal of this work was to evaluate and compare the effectiveness of low-cost and engineered materials for P removal from NOM-rich surface water. Seven low-cost materials and three engineered materials were evaluated using jar tests and mini-column experiments. The test water was a surface water that had a total P concentration of 132-250 μg P/L and a total organic carbon concentration of 15-32 mg C/L. Alum sludge, a byproduct of drinking water treatment, and a hybrid anion exchange resin loaded with nanosize iron oxide were the best performing materials in terms of selective P removal in the presence of NOM and minimum undesirable secondary changes to the water chemistry. Copyright © 2011 Elsevier Ltd. All rights reserved.

Questa baseline and pre-mining ground-water quality investigation. 5. Well installation, water-level data, and surface- and ground-water geochemistry in the Straight Creek drainage basin, Red River Valley, New Mexico, 2001-03

USGS Publications Warehouse

Naus, Cheryl A.; McCleskey, R. Blaine; Nordstrom, D. Kirk; Donohoe, Lisa C.; Hunt, Andrew G.; Paillet, Frederick L.; Morin, Roger H.; Verplanck, Philip L.

2005-01-01

selected samplings. One set of ground-water samples was collected for helium-3/tritium and chlorofluorocarbon (CFC) age dating. Several lines of evidence indicate that surface water is the primary input to the Straight Creek ground-water system. Straight Creek streamflow and water levels in wells closest to the apex of the Straight Creek debris fan and closest to Straight Creek itself appear to respond to the same seasonal inputs. Oxygen and hydrogen isotopic compositions in Straight Creek surface water and ground water are similar, and concentrations of most dissolved constituents in most Straight Creek surface-water and shallow (debris-flow and alluvial) aquifer ground-water samples correlate strongly with sulfate (concentrations decrease linearly with sulfate in a downgradient direction). After infiltration of surface water, dilution along the flow path is the dominant mechanism controlling ground-water chemistry. However, concentrations of some constituents can be higher in ground water than can be accounted for by concentrations in Straight Creek surface water, and additional sources of these constituents must therefore be inferred. Constituents for which concentrations in ground water can be high relative to surface water include calcium, magnesium, strontium, silica, sodium, and potassium in ground water from debris-flow and alluvial aquifers and manganese, calcium, magnesium, strontium, sodium, and potassium in ground water from the bedrock aquifer. All ground water is a calcium sulfate type, often at or near gypsum saturation because of abundant gypsum in the aquifer material developed from co-existing calcite and pyrite mineralization. Calcite dissolution, the major buffering mechanism for bedrock aquifer ground water, also contributes to relatively higher calcium concentrations in some ground water. The main source of the second most abundant cation, magnesium, is probably dissolution of magnesium-rich carbonates or silicates. Strontium may also be

Planetary-scale surface water detection from space

NASA Astrophysics Data System (ADS)

Donchyts, G.; Baart, F.; Winsemius, H.; Gorelick, N.

2017-12-01

Accurate, efficient and high-resolution methods of surface water detection are needed for a better water management. Datasets on surface water extent and dynamics are crucial for a better understanding of natural and human-made processes, and as an input data for hydrological and hydraulic models. In spite of considerable progress in the harmonization of freely available satellite data, producing accurate and efficient higher-level surface water data products remains very challenging. This presentation will provide an overview of existing methods for surface water extent and change detection from multitemporal and multi-sensor satellite imagery. An algorithm to detect surface water changes from multi-temporal satellite imagery will be demonstrated as well as its open-source implementation (http://aqua-monitor.deltares.nl). This algorithm was used to estimate global surface water changes at high spatial resolution. These changes include climate change, land reclamation, reservoir construction/decommissioning, erosion/accretion, and many other. This presentation will demonstrate how open satellite data and open platforms such as Google Earth Engine have helped with this research.

Controllability of Surface Water Networks

NASA Astrophysics Data System (ADS)

Riasi, M. Sadegh; Yeghiazarian, Lilit

2017-12-01

To sustainably manage water resources, we must understand how to control complex networked systems. In this paper, we study surface water networks from the perspective of structural controllability, a concept that integrates classical control theory with graph-theoretic formalism. We present structural controllability theory and compute four metrics: full and target controllability, control centrality and control profile (FTCP) that collectively determine the structural boundaries of the system's control space. We use these metrics to answer the following questions: How does the structure of a surface water network affect its controllability? How to efficiently control a preselected subset of the network? Which nodes have the highest control power? What types of topological structures dominate controllability? Finally, we demonstrate the structural controllability theory in the analysis of a wide range of surface water networks, such as tributary, deltaic, and braided river systems.

Patterns of rare and abundant marine microbial eukaryotes.

PubMed

Logares, Ramiro; Audic, Stéphane; Bass, David; Bittner, Lucie; Boutte, Christophe; Christen, Richard; Claverie, Jean-Michel; Decelle, Johan; Dolan, John R; Dunthorn, Micah; Edvardsen, Bente; Gobet, Angélique; Kooistra, Wiebe H C F; Mahé, Frédéric; Not, Fabrice; Ogata, Hiroyuki; Pawlowski, Jan; Pernice, Massimo C; Romac, Sarah; Shalchian-Tabrizi, Kamran; Simon, Nathalie; Stoeck, Thorsten; Santini, Sébastien; Siano, Raffaele; Wincker, Patrick; Zingone, Adriana; Richards, Thomas A; de Vargas, Colomban; Massana, Ramon

2014-04-14

Biological communities are normally composed of a few abundant and many rare species. This pattern is particularly prominent in microbial communities, in which most constituent taxa are usually extremely rare. Although abundant and rare subcommunities may present intrinsic characteristics that could be crucial for understanding community dynamics and ecosystem functioning, microbiologists normally do not differentiate between them. Here, we investigate abundant and rare subcommunities of marine microbial eukaryotes, a crucial group of organisms that remains among the least-explored biodiversity components of the biosphere. We surveyed surface waters of six separate coastal locations in Europe, independently considering the picoplankton, nanoplankton, and microplankton/mesoplankton organismal size fractions. Deep Illumina sequencing of the 18S rRNA indicated that the abundant regional community was mostly structured by organismal size fraction, whereas the rare regional community was mainly structured by geographic origin. However, some abundant and rare taxa presented similar biogeography, pointing to spatiotemporal structure in the rare microeukaryote biosphere. Abundant and rare subcommunities presented regular proportions across samples, indicating similar species-abundance distributions despite taxonomic compositional variation. Several taxa were abundant in one location and rare in other locations, suggesting large oscillations in abundance. The substantial amount of metabolically active lineages found in the rare biosphere suggests that this subcommunity constitutes a diversity reservoir that can respond rapidly to environmental change. We propose that marine planktonic microeukaryote assemblages incorporate dynamic and metabolically active abundant and rare subcommunities, with contrasting structuring patterns but fairly regular proportions, across space and time. Copyright © 2014 Elsevier Ltd. All rights reserved.

Can water-level management reduce malaria mosquito abundance around large dams in sub-Saharan Africa?

PubMed Central

Wilson, G. Glenn; Ryder, Darren; Tekie, Habte; Petros, Beyene

2018-01-01

Background Water level management has been suggested as a potential tool to reduce malaria around large reservoirs. However, no field-based test has been conducted to assess the effect of water level management on mosquito larval abundance in African settings. The objective of the present study is to evaluate the effects of water level drawdown rates on mosquito larval abundance. Methods Twelve experimental dams were constructed on the foreshore of the Koka Dam in Ethiopia. These were grouped into four daily water drawdown treatments, each with three replicates: no water-level drawdown (Group 1; Control), 10 mm.d-1 (Group 2), 15 mm.d-1 (Group 3) and 20 mm.d-1 (Group 4). Larval sampling was conducted weekly for a period of 6 weeks each in the main malaria transmission season (October to November 2013) and subsequent dry season (February to March 2014). Larval densities were compared among treatments over time using repeated measures Analysis of Variance (ANOVA). Results A total of 284 Anopheles mosquito larvae were collected from the experimental dams during the study period. Most (63.4%; n = 180) were collected during the main malaria transmission season while the remaining (36.6%; n = 104) were collected during the dry season. Larvae comprised four Anopheles species, dominated by Anopheles arabiensis (48.1% of total larval samples; n = 136) and An. pharoensis (33.2%; n = 94). Mean larval density was highest in control treatment dams with stable water levels throughout the study, and decreased significantly (P < 0.05) with increasing water drawdown rates in both seasons. During the main transmission season, anopheline larval density was generally lower by 30%, 70% and 84% in Groups 2, Group 3 and Group 4, respectively, compared with the control dams (Group 1). In the dry season, larval density was reduced by 45%, 70% and 84% in Groups 2, Group 3 and Group 4, respectively, when compared to the control dams. Conclusion Increased water drawdown rates were associated

Community composition, abundance and biomass of zooplankton in Zhangzi Island waters, Northern Yellow Sea

NASA Astrophysics Data System (ADS)

Yin, Jiehui; Zhang, Guangtao; Li, Chaolun; Wang, Shiwei; Zhao, Zengxia; Wan, Aiyong

2017-09-01

Samples were collected monthly from the sea area around Zhangzi Island, northern Yellow Sea, from July 2009 to June 2010. Vertical net towing was used to examine spatial and temporal variability in zooplankton abundance and biomass. Overall, Calanus sinicus and Saggita crassa were the dominant species found during the study period, while the amphipod Themisto gracilipes was dominant in winter and spring. Vast numbers of the ctenophore species of the genus Beroe were found in October and November. It was not possible to count them, but they constituted a large portion of the total zooplankton biomass. Zooplankton species diversity was highest in October, and species evenness was highest in April. Zooplankton abundance (non-jellyfish) and biomass were highest in June and lowest in August, with annual averages of 131.3 ind./m³ and 217.5 mg/m³, respectively. Water temperature may be responsible for the variations in zooplankton abundance and biomass. Beroe biomass was negatively correlated with other zooplankton abundance. Longterm investigations will be carried out to learn more about the influence of the environment on zooplankton assemblages.

Occurrence, distribution and risk assessment of organophosphate esters in surface water and sediment from a shallow freshwater Lake, China.

PubMed

Xing, Liqun; Zhang, Qin; Sun, Xu; Zhu, Hongxia; Zhang, Shenghu; Xu, Huaizhou

2018-04-30

Organophosphate esters (OPEs) are ubiquitous in the environment and pose a potential threat to ecosystem and human health. This study investigated the concentrations, distributions and risk of 12 OPEs in surface water and sediment from Luoma Lake, Fangting River and Yi River. Solid-phase extraction (SPE) method were used to extract OPEs from water samples, ultrasonic process and SPE method were used to extract OPEs from sediment samples, and the extracts were finally analyzed using the HPLC-MS/MS. The results revealed that the median and maximum concentrations of ΣOPEs were 73.9 and 1066 ng/L in surface water, and were 28.7 and 35.9 ng/g in sediment, respectively. Tris(2-chloroethyl) phosphate (TCEP) and trimethyl phosphate (TMP) were the most abundant OPEs in the surface water with median concentrations of 24.3 and 16.4 ng/L in Luoma Lake, respectively. Triethyl phosphate (TEP) was the most abundant OPE in the sediment with a median concentrations of 28.9 ng/g. However, tricresyl phosphate (TCrP) and ethylhexyl diphenyl phosphate (EHDPP) predominantly contributed to the ecological risk with respective median risk quotients 0.07 and 0.01 for surface water in Luoma Lake. TEP and TCrP were the most significant contributors to the ecological risk with respective median risk quotients of 6.4 × 10 -4 and 5.6 × 10 -4 for sediment. It was also found that inflowing Fangting River could be the major pollution source to Luoma Lake. The no-cancer and carcinogenic risks of OPEs were lower than the theoretical threshold of risk. The study found that the ecological and human health risks due to the exposure to OPEs were currently acceptable. In other words, the Luoma Lake was relatively safer to use as a drinking water source in urban areas in the context of OPEs pollution. Copyright © 2018 Elsevier B.V. All rights reserved.

Impact of Water Withdrawals from Groundwater and Surface Water on Continental Water Storage Variations

NASA Technical Reports Server (NTRS)

Doell, Petra; Hoffmann-Dobrev, Heike; Portmann, Felix T.; Siebert, Stefan; Eicker, Annette; Rodell, Matthew; Strassberg, Gil

2011-01-01

Humans have strongly impacted the global water cycle, not only water flows but also water storage. We have performed a first global-scale analysis of the impact of water withdrawals on water storage variations, using the global water resources and use model WaterGAP. This required estimation of fractions of total water withdrawals from groundwater, considering five water use sectors. According to our assessment, the source of 35% of the water withdrawn worldwide (4300 cubic km/yr during 1998-2002) is groundwater. Groundwater contributes 42%, 36% and 27% of water used for irrigation, households and manufacturing, respectively, while we assume that only surface water is used for livestock and for cooling of thermal power plants. Consumptive water use was 1400 cubic km/yr during 1998-2002. It is the sum of the net abstraction of 250 cubic km/yr of groundwater (taking into account evapotranspiration and return flows of withdrawn surface water and groundwater) and the net abstraction of 1150 km3/yr of surface water. Computed net abstractions indicate, for the first time at the global scale, where and when human water withdrawals decrease or increase groundwater or surface water storage. In regions with extensive surface water irrigation, such as Southern China, net abstractions from groundwater are negative, i.e. groundwater is recharged by irrigation. The opposite is true for areas dominated by groundwater irrigation, such as in the High Plains aquifer of the central USA, where net abstraction of surface water is negative because return flow of withdrawn groundwater recharges the surface water compartments. In intensively irrigated areas, the amplitude of seasonal total water storage variations is generally increased due to human water use; however, in some areas, it is decreased. For the High Plains aquifer and the whole Mississippi basin, modeled groundwater and total water storage variations were compared with estimates of groundwater storage variations based on

Vernal distribution and turnover of dimethylsulfide (DMS) in the surface water of the Yellow Sea

NASA Astrophysics Data System (ADS)

Li, Cheng-Xuan; Yang, Gui-Peng; Wang, Bao-Dong; Xu, Zong-Jun

2016-10-01

The spatial and interannual variations of dimethylsulfide (DMS) and its precursors, dissolved and particulate dimethylsulfoniopropionate (DMSP), were discussed on the basis of field observations in the surface waters of the Yellow Sea during spring 2007. Maxima of dimethylated sulfur compounds and low chlorophyll a concentrations were found in the central southern Yellow Sea, whereas low concentrations of DMS and DMSP were detected at the boundary between the northern and southern parts of the Yellow Sea. This frontal region is influenced by active water currents, air-sea interface exchanges, and biological turnover. The horizontal variations in DMS production and consumption rates showed a decreasing tendency from the coastal to offshore areas mainly due to the complicated biological features. DMS positively correlated with dissolved CH4 and CO2 but negatively correlated with nutrients (nitrite and phosphate). Particulate DMSP concentrations and DMS production rates positively correlated with dinoflagellate abundances but negatively correlated with diatom cell densities. DMS and DMSP concentrations, as well as DMS production and consumption rates, exhibited approximately 2.0-2.8 fold increases from 2005 to 2012. This finding was likely caused by shifts in the phytoplankton communities from diatoms to dinoflagellates and the increases in abundances of zooplankton and bacteria. Average sea-to-air DMS fluxes were estimated to be 8.12 ± 1.24 µmol·(m-2·d-1), and DMS microbial consumption was approximately 1.68 times faster than the DMS sea-air exchange. These findings imply that biological consumption, relative to ventilation, is a predominant mechanism in DMS removal from the surface water.

Correlation Between Existence of Reef Sharks with Abundance of Reef Fishes in South Waters of Morotai Island (North Moluccas)

NASA Astrophysics Data System (ADS)

Mukharror, Darmawan Ahmad; Tiara Baiti, Isnaini; Ichsan, Muhammad; Pridina, Niomi; Triutami, Sanny

2017-10-01

Despite increasing academic research citation on biology, abundance, and the behavior of the blacktip reef sharks, the influence of reef fish population on the density of reef sharks: Carcharhinus melanopterus and Triaenodon obesus population in its habitat were largely unassessed. This present study examined the correlation between abundance of reef fishes family/species with the population of reef sharks in Southern Waters of Morotai Island. The existence of reef sharks was measured with the Audible Stationary Count (ASC) methods and the abundance of reef fishes was surveyed using Underwater Visual Census (UVC) combined with Diver Operated Video (DOV) census. The coefficient of Determination (R2) was used to investigate the degree of relationships between sharks and the specific reef fishes species. The research from 8th April to 4th June 2015 showed the strong positive correlations between the existence of reef sharks with abundance of reef fishes. The correlation values between Carcharhinus melanopterus/Triaenodon obesus with Chaetodon auriga was 0.9405, blacktip/whitetip reef sharks versus Ctenochaetus striatus was 0.9146, and Carcharhinus melanopterus/Triaenodon obesus to Chaetodon kleinii was 0.8440. As the shark can be worth more alive for shark diving tourism than dead in a fish market, the abundance of these reef fishes was important as an early indication parameter of shark existence in South Water of Morotai Island. In the long term, this highlights the importance of reef fishes abundance management in Morotai Island’s Waters to enable the establishment of appropriate and effective reef sharks conservation.

Surface water records of New Mexico, water year 1961

USGS Publications Warehouse

,

1962-01-01

The surface-water records for the 1961 water year for gaging stations, partial-record stations, and miscellaneous sites within the State of New Mexico are given in this report. For convenience there are also included for a few pertinent gaging stations in bordering States. The records were collected and computed by the Water Resources Division of the U. S. Geological Survey, under the direction of W. L. Heckler, district engineer, Surface Water Branch. This report marks the beginning of a new method of presenting, annually, basic data on surface-water records by States. Through September 30, 1960, the records of discharge and stage of streams and contents and stage of lakes or reservoirs were published in an annual series of U. S. Geological Survey water supply papers entitled "Surface Water Supply of the United States." Since 1951 there has been 20 volumes in the series; each volume covered an area whose boundaries coincided with those of certain natural drainage areas. The records in New Mexico were contained in Parts 7, 8, and 9 of that series. Beginning with the 1961 water year, streamflow records and related data will be released by the Geological Survey in annual reports On a State-boundary basis. Distribution of these basic-data reports will be limited and primarily for local needs. The records later will be published in Geological Survey watersupply paper at 5-year intervals. These 5-year water-supply papers will show daily discharge and will be compiled on the same geographical areas previously used for the annual series; however, some of the 14 parts of conterminous United States will be further subdivided.

Surface water records of Colorado, 1961

USGS Publications Warehouse

U.S. Geological Survey, Water Resources Division

1961-01-01

The surface-water records for the 1961 water year for gaging stations and miscellaneous sites within the State of Colorado are given in this report. For convenience there are also included records for a few pertinent gaging stations in bordering States. The records were collected and computed by the Water Resources Division of the U.S. Geological Survey, under the direction of W. T. Miller, district engineer, Surface Water Branch, succeeded by J. W. Odell.

Imbalance in Groundwater-Surface Water Interactions and its Relationship to the Coastal Zone Hazards

NASA Astrophysics Data System (ADS)

Kontar, Y. A.; Ozorovich, Y. R.; Salokhiddinov, A. T.

2011-12-01

We report here some efforts and results in studying the imbalance in groundwater-surface water interactions and processes of groundwater-surface water interactions and groundwater flooding creating hazards in the coastal zones. Hazards, hydrological and geophysical risk analysis related to imbalance in groundwater-surface water interactions and groundwater flooding have been to a large extent under-emphasized for coastal zone applications either due to economical limitations or underestimation of significance of imbalance in groundwater-surface water interactions. This is particularly true for tsunamis creating salt water intrusion to coastal aquifers, even though most tsunami hazard assessments have in the past relied on scenario or deterministic type models, and to increasing mineralization of potable water because of intensive water diversions and also the abundance of highly toxic pollutants (mainly pesticides) in water, air and food, which contribute to the deterioration of the coastal population's health. In the wake of pressing environmental and economic issues, it is of prime importance for the scientific community to shed light onto the great efforts by hydrologists and geophysicists to quantify conceptual uncertainties and to provide quality assurances of potential coastal zone hazard evaluation and prediction under conditions of imbalance in groundwater-surface water interactions. This paper proposes consideration of two case studies which are important and significant for future understanding of a concept of imbalance in groundwater-surface water interactions and development and essential for feasibility studies of hazards in the coastal zone. The territory of the Aral Sea Region in Central Asia is known as an ecological disaster coastal zone. It is now obvious that, in order to provide reasonable living conditions to the coastal zone population, it is first of all necessary to drastically improve the quality of the water dedicated to human needs. Due

Bacterial pathogen gene abundance and relation to recreational water quality at seven Great Lakes beaches.

PubMed

Oster, Ryan J; Wijesinghe, Rasanthi U; Haack, Sheridan K; Fogarty, Lisa R; Tucker, Taaja R; Riley, Stephen C

2014-12-16

Quantitative assessment of bacterial pathogens, their geographic variability, and distribution in various matrices at Great Lakes beaches are limited. Quantitative PCR (qPCR) was used to test for genes from E. coli O157:H7 (eaeO157), shiga-toxin producing E. coli (stx2), Campylobacter jejuni (mapA), Shigella spp. (ipaH), and a Salmonella enterica-specific (SE) DNA sequence at seven Great Lakes beaches, in algae, water, and sediment. Overall, detection frequencies were mapA>stx2>ipaH>SE>eaeO157. Results were highly variable among beaches and matrices; some correlations with environmental conditions were observed for mapA, stx2, and ipaH detections. Beach seasonal mean mapA abundance in water was correlated with beach seasonal mean log10 E. coli concentration. At one beach, stx2 gene abundance was positively correlated with concurrent daily E. coli concentrations. Concentration distributions for stx2, ipaH, and mapA within algae, sediment, and water were statistically different (Non-Detect and Data Analysis in R). Assuming 10, 50, or 100% of gene copies represented viable and presumably infective cells, a quantitative microbial risk assessment tool developed by Michigan State University indicated a moderate probability of illness for Campylobacter jejuni at the study beaches, especially where recreational water quality criteria were exceeded. Pathogen gene quantification may be useful for beach water quality management.

Insight into Chemistry on Cloud/Aerosol Water Surfaces.

PubMed

Zhong, Jie; Kumar, Manoj; Francisco, Joseph S; Zeng, Xiao Cheng

2018-05-15

Cloud/aerosol water surfaces exert significant influence over atmospheric chemical processes. Atmospheric processes at the water surface are observed to follow mechanisms that are quite different from those in the gas phase. This Account summarizes our recent findings of new reaction pathways on the water surface. We have studied these surface reactions using Born-Oppenheimer molecular dynamics simulations. These studies provide useful information on the reaction time scale, the underlying mechanism of surface reactions, and the dynamic behavior of the product formed on the aqueous surface. According to these studies, the aerosol water surfaces confine the atmospheric species into a specific orientation depending on the hydrophilicity of atmospheric species or the hydrogen-bonding interactions between atmospheric species and interfacial water. As a result, atmospheric species are activated toward a particular reaction on the aerosol water surface. For example, the simplest Criegee intermediate (CH 2 OO) exhibits high reactivity toward the interfacial water and hydrogen sulfide, with the reaction times being a few picoseconds, 2-3 orders of magnitude faster than that in the gas phase. The presence of interfacial water molecules induces proton-transfer-based stepwise pathways for these reactions, which are not possible in the gas phase. The strong hydrophobicity of methyl substituents in larger Criegee intermediates (>C1), such as CH 3 CHOO and (CH 3 ) 2 COO, blocks the formation of the necessary prereaction complexes for the Criegee-water reaction to occur at the water droplet surface, which lowers their proton-transfer ability and hampers the reaction. The aerosol water surface provides a solvent medium for acids (e.g., HNO 3 and HCOOH) to participate in reactions via mechanisms that are different from those in the gas and bulk aqueous phases. For example, the anti-CH 3 CHOO-HNO 3 reaction in the gas phase follows a direct reaction between anti-CH 3 CHOO and HNO 3

Distribution in the abundance and biomass of shelled pteropods in surface waters of the Indian sector of the Antarctic Ocean in mid-summer

NASA Astrophysics Data System (ADS)

Akiha, Fumihiro; Hashida, Gen; Makabe, Ryosuke; Hattori, Hiroshi; Sasaki, Hiroshi

2017-06-01

We investigated shelled pteropod abundance and biomass with a 100-μm closing net, and their estimated downward fluxes using a sediment trap installed in a drifter buoy in the Indian sector of the Antarctic Ocean during the austral summer. Over 90% pteropod abundance was distributed in the upper 50 m; 70-100% were immature veligers. Limacina retroversa was dominant in the >0.2 mm individuals north of 60°S, L. helicina dominated south of 62°S, while populations around 60-62°S were mixed. Unidentifiable small Limacina spp. (ssL) were highly abundant in the upper 50 m at 60°S, 63°S, and 64°S on 110°E and 63°S on 115°E, although their estimated particulate organic carbon (POC) biomasses were less than that of Limacina adults. Adult females bearing egg clusters were found in the 0-50 m layer; the veligers likely grew within a short period. The mean downward flux of ssL and veligers at 70 m around 60°S, 110°E was 5.1 ± 1.6 × 103 ind. m-2 d-1 (0.6 ± 0.2 mg C m-2 d-1), which was 3.8% of the integrated ssL and veligers in the upper 70 m, suggesting that at least 4% of the veligers were produced daily in the surface layers. The mid-summer spawned ssL and veligers likely contributed to the subsequent increase in large pteropods in the area.

Investigating surface water-well interaction using stable isotope ratios of water

USGS Publications Warehouse

Hunt, R.J.; Coplen, T.B.; Haas, N.L.; Saad, D.A.; Borchardt, M. A.

2005-01-01

Because surface water can be a source of undesirable water quality in a drinking water well, an understanding of the amount of surface water and its travel time to the well is needed to assess a well's vulnerability. Stable isotope ratios of oxygen in river water at the City of La Crosse, Wisconsin, show peak-to-peak seasonal variation greater than 4??? in 2001 and 2002. This seasonal signal was identified in 7 of 13 city municipal wells, indicating that these 7 wells have appreciable surface water contributions and are potentially vulnerable to contaminants in the surface water. When looking at wells with more than 6 sampling events, a larger variation in ??18O compositions correlated with a larger fraction of surface water, suggesting that samples collected for oxygen isotopic composition over time may be useful for identifying the vulnerability to surface water influence even if a local meteoric water line is not available. A time series of ??18O from one of the municipal wells and from a piezometer located between the river and the municipal well showed that the travel time of flood water to the municipal well was approximately 2 months; non-flood arrival times were on the order of 9 months. Four independent methods were also used to assess time of travel. Three methods (groundwater temperature arrival times at the intermediate piezometer, virus-culture results, and particle tracking using a numerical groundwater-flow model) yielded flood and non-flood travel times of less than 1 year for this site. Age dating of one groundwater sample using 3H-3He methods estimated an age longer than 1 year, but was likely confounded by deviations from piston flow as noted by others. Chlorofluorocarbons and SF6 analyses were not useful at this site due to degradation and contamination, respectively. This work illustrates the utility of stable hydrogen and oxygen isotope ratios of water to determine the contribution and travel time of surface water in groundwater, and

Monitoring of Water and Contaminant Migration at the Groundwater-Surface Water Interface

DTIC Science & Technology

2008-08-01

seepage is occurring in a freshwater lake environment and to map the lateral extent of any subsurface contamination at the groundwater –surface water ...and Contaminant Migration at the Groundwater -Surface Water Interface August 2008 Report Documentation Page Form ApprovedOMB No. 0704-0188 Public...4. TITLE AND SUBTITLE Monitoring of Water and Contaminant Migration at the Groundwater -Surface Water Interface 5a. CONTRACT NUMBER 5b. GRANT NUMBER

Millennial-scale changes of surface and bottom water conditions in the northwestern Pacific during the last deglaciation

NASA Astrophysics Data System (ADS)

Kim, Sunghan; Khim, Boo-Keun; Ikehara, Ken; Itaki, Takuya; Shibahara, Akihiko; Yamamoto, Masanobu

2017-07-01

Changes in water column conditions in the northwestern Pacific during the last 23 ka were reconstructed using geochemical and isotope proxies and redox elemental compositions along with published data (alkenone sea surface temperature (SST) and benthic foraminiferal fauna) at core GH02-1030. Surface water primary productivity in terms of biogenic opal and TOC contents, which mainly represented export production of diatom, was closely related to alkenone (spring-summer) SST and the development of spring-summer mixed layer depth. The different variation patterns of nitrate and silicic acid utilization, estimated by bulk δ15N and δ30Sidiatom values, respectively, are most likely due to the water column denitrification influence on bulk δ15N. Dysoxic bottom water conditions occurred during the Bølling-Allerød (BA) and the Pre-Boreal (PB), which was evident by laminated sediments, abundant dysoxic benthic foraminifers, and increased redox elemental compositions. Although surface water productivity increased during the BA and PB, dysoxic bottom water conditions were caused by a combination of enhanced surface water productivity and reduced ventilation of North Pacific Intermediate Water (NPIW) in response to meltwater input from the high latitude areas. Based on records of core GH02-1030 and other cores in the northwestern Pacific, the Okhotsk Sea, and the Bering Sea, which are all proximal to the modern NPIW source region, dissolved oxygen concentrations of bottom water were more depleted during the BA than PB. Such difference was attributed to more sluggish NPIW ventilation due to more meltwater input during the BA than the PB. The opening or closure of the Bering Strait is critical to the direction of meltwater transport to the northwestern Pacific.

The effects of environmental factors on daytime sandeel distribution and abundance on the Dogger Bank

NASA Astrophysics Data System (ADS)

van der Kooij, Jeroen; Scott, Beth E.; Mackinson, Steven

2008-10-01

Spring distribution and abundance of lesser sandeels during the day were linked to zooplankton densities, seabed substrate and various hydrographic factors using small scale empirical data collected in two areas on the Dogger Bank in 2004, 2005 and 2006. The results of a two-step generalized additive model (GAM) suggested that suitable seabed substrate and temperature best explain sandeel distribution (presence/absence) and that sandeel abundance (given presence) was best described by a model that included bottom temperature, difference between surface and bottom temperature and surface salinity. The current study suggests that suitable seabed substrate explains sandeel distribution in the water column. Bottom temperature and surface salinity also played an important role in explaining distribution and abundance, and we speculate that sandeels favour hydrographically dynamic areas. Contrary to our hypothesis sandeels were not strongly associated with areas of high zooplankton density. We speculate that in early spring on the western Dogger Bank plankton is still patchily distributed and that sandeels only emerge from the seabed when feeding conditions near their night-time burrowing habitat are optimal. The results also suggested that when abundance is over a threshold level, the number of sandeel schools increased rather than the schools becoming bigger. This relationship between patchiness and abundance has implications for mortality rates and hence fisheries management.

Thermal desorption of formamide and methylamine from graphite and amorphous water ice surfaces

NASA Astrophysics Data System (ADS)

Chaabouni, H.; Diana, S.; Nguyen, T.; Dulieu, F.

2018-04-01

Context. Formamide (NH2CHO) and methylamine (CH3NH2) are known to be the most abundant amine-containing molecules in many astrophysical environments. The presence of these molecules in the gas phase may result from thermal desorption of interstellar ices. Aims: The aim of this work is to determine the values of the desorption energies of formamide and methylamine from analogues of interstellar dust grain surfaces and to understand their interaction with water ice. Methods: Temperature programmed desorption (TPD) experiments of formamide and methylamine ices were performed in the sub-monolayer and monolayer regimes on graphite (HOPG) and non-porous amorphous solid water (np-ASW) ice surfaces at temperatures 40-240 K. The desorption energy distributions of these two molecules were calculated from TPD measurements using a set of independent Polanyi-Wigner equations. Results: The maximum of the desorption of formamide from both graphite and ASW ice surfaces occurs at 176 K after the desorption of H2O molecules, whereas the desorption profile of methylamine depends strongly on the substrate. Solid methylamine starts to desorb below 100 K from the graphite surface. Its desorption from the water ice surface occurs after 120 K and stops during the water ice sublimation around 150 K. It continues to desorb from the graphite surface at temperatures higher than160 K. Conclusions: More than 95% of solid NH2CHO diffuses through the np-ASW ice surface towards the graphitic substrate and is released into the gas phase with a desorption energy distribution Edes = 7460-9380 K, which is measured with the best-fit pre-exponential factor A = 1018 s-1. However, the desorption energy distribution of methylamine from the np-ASW ice surface (Edes = 3850-8420 K) is measured with the best-fit pre-exponential factor A = 1012 s-1. A fraction of solid methylamine monolayer of roughly 0.15 diffuses through the water ice surface towards the HOPG substrate. This small amount of methylamine

The Dynamic Surface Tension of Water

PubMed Central

2017-01-01

The surface tension of water is an important parameter for many biological or industrial processes, and roughly a factor of 3 higher than that of nonpolar liquids such as oils, which is usually attributed to hydrogen bonding and dipolar interactions. Here we show by studying the formation of water drops that the surface tension of a freshly created water surface is even higher (∼90 mN m–1) than under equilibrium conditions (∼72 mN m–1) with a relaxation process occurring on a long time scale (∼1 ms). Dynamic adsorption effects of protons or hydroxides may be at the origin of this dynamic surface tension. However, changing the pH does not significantly change the dynamic surface tension. It also seems unlikely that hydrogen bonding or dipole orientation effects play any role at the relatively long time scale probed in the experiments. PMID:28301160

The Dynamic Surface Tension of Water.

PubMed

Hauner, Ines M; Deblais, Antoine; Beattie, James K; Kellay, Hamid; Bonn, Daniel

2017-04-06

The surface tension of water is an important parameter for many biological or industrial processes, and roughly a factor of 3 higher than that of nonpolar liquids such as oils, which is usually attributed to hydrogen bonding and dipolar interactions. Here we show by studying the formation of water drops that the surface tension of a freshly created water surface is even higher (∼90 mN m -1 ) than under equilibrium conditions (∼72 mN m -1 ) with a relaxation process occurring on a long time scale (∼1 ms). Dynamic adsorption effects of protons or hydroxides may be at the origin of this dynamic surface tension. However, changing the pH does not significantly change the dynamic surface tension. It also seems unlikely that hydrogen bonding or dipole orientation effects play any role at the relatively long time scale probed in the experiments.

Large-scale geographic variation in distribution and abundance of Australian deep-water kelp forests.

PubMed

Marzinelli, Ezequiel M; Williams, Stefan B; Babcock, Russell C; Barrett, Neville S; Johnson, Craig R; Jordan, Alan; Kendrick, Gary A; Pizarro, Oscar R; Smale, Dan A; Steinberg, Peter D

2015-01-01

Despite the significance of marine habitat-forming organisms, little is known about their large-scale distribution and abundance in deeper waters, where they are difficult to access. Such information is necessary to develop sound conservation and management strategies. Kelps are main habitat-formers in temperate reefs worldwide; however, these habitats are highly sensitive to environmental change. The kelp Ecklonia radiate is the major habitat-forming organism on subtidal reefs in temperate Australia. Here, we provide large-scale ecological data encompassing the latitudinal distribution along the continent of these kelp forests, which is a necessary first step towards quantitative inferences about the effects of climatic change and other stressors on these valuable habitats. We used the Autonomous Underwater Vehicle (AUV) facility of Australia's Integrated Marine Observing System (IMOS) to survey 157,000 m2 of seabed, of which ca 13,000 m2 were used to quantify kelp covers at multiple spatial scales (10-100 m to 100-1,000 km) and depths (15-60 m) across several regions ca 2-6° latitude apart along the East and West coast of Australia. We investigated the large-scale geographic variation in distribution and abundance of deep-water kelp (>15 m depth) and their relationships with physical variables. Kelp cover generally increased with latitude despite great variability at smaller spatial scales. Maximum depth of kelp occurrence was 40-50 m. Kelp latitudinal distribution along the continent was most strongly related to water temperature and substratum availability. This extensive survey data, coupled with ongoing AUV missions, will allow for the detection of long-term shifts in the distribution and abundance of habitat-forming kelp and the organisms they support on a continental scale, and provide information necessary for successful implementation and management of conservation reserves.

Large-Scale Geographic Variation in Distribution and Abundance of Australian Deep-Water Kelp Forests

PubMed Central

Marzinelli, Ezequiel M.; Williams, Stefan B.; Babcock, Russell C.; Barrett, Neville S.; Johnson, Craig R.; Jordan, Alan; Kendrick, Gary A.; Pizarro, Oscar R.; Smale, Dan A.; Steinberg, Peter D.

2015-01-01

Despite the significance of marine habitat-forming organisms, little is known about their large-scale distribution and abundance in deeper waters, where they are difficult to access. Such information is necessary to develop sound conservation and management strategies. Kelps are main habitat-formers in temperate reefs worldwide; however, these habitats are highly sensitive to environmental change. The kelp Ecklonia radiate is the major habitat-forming organism on subtidal reefs in temperate Australia. Here, we provide large-scale ecological data encompassing the latitudinal distribution along the continent of these kelp forests, which is a necessary first step towards quantitative inferences about the effects of climatic change and other stressors on these valuable habitats. We used the Autonomous Underwater Vehicle (AUV) facility of Australia’s Integrated Marine Observing System (IMOS) to survey 157,000 m2 of seabed, of which ca 13,000 m2 were used to quantify kelp covers at multiple spatial scales (10–100 m to 100–1,000 km) and depths (15–60 m) across several regions ca 2–6° latitude apart along the East and West coast of Australia. We investigated the large-scale geographic variation in distribution and abundance of deep-water kelp (>15 m depth) and their relationships with physical variables. Kelp cover generally increased with latitude despite great variability at smaller spatial scales. Maximum depth of kelp occurrence was 40–50 m. Kelp latitudinal distribution along the continent was most strongly related to water temperature and substratum availability. This extensive survey data, coupled with ongoing AUV missions, will allow for the detection of long-term shifts in the distribution and abundance of habitat-forming kelp and the organisms they support on a continental scale, and provide information necessary for successful implementation and management of conservation reserves. PMID:25693066

First-principles study of water desorption from montmorillonite surface.

PubMed

Zhang, Yao; Meng, Yingfeng; Liu, Houbin; Yang, Mingli

2016-05-01

Knowledge about water desorption is important to give a full picture of water diffusion in montmorillonites (MMT), which is a driving factor in MMT swelling. The desorption paths and energetics of water molecules from the surface of MMT with trapped Li(+), Na(+) or K(+) counterions were studied using periodic density functional theory calculations. Two paths--surface and vacuum desorption--were designed for water desorption starting from a stationary structure in which water bonds with both the counterion and the MMT surface. Surface desorption is energetically more favorable than vacuum desorption due to water-surface hydrogen bonds that help stabilize the intermediate structure of water released from the counterion. The energy barriers of water desorption are in the order of Li(+) > Na(+) > K(+), which can be attributed to the short ionic radius of Li(+), which favors strong binding with the water molecule. The temperature dependence of water adsorption and desorption rates were compared based on the computed activation energies. Our calculations reveal that the water desorption on the MMT surface has a different mechanism from water adsorption, which results from surface effects favoring stabilization of water conformers during the desorption process.

40 CFR 258.27 - Surface water requirements.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 24 2010-07-01 2010-07-01 false Surface water requirements. 258.27... FOR MUNICIPAL SOLID WASTE LANDFILLS Operating Criteria § 258.27 Surface water requirements. MSWLF... wetlands, that violates any requirements of the Clean Water Act, including, but not limited to, the...

40 CFR 258.27 - Surface water requirements.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 26 2012-07-01 2011-07-01 true Surface water requirements. 258.27... FOR MUNICIPAL SOLID WASTE LANDFILLS Operating Criteria § 258.27 Surface water requirements. MSWLF... wetlands, that violates any requirements of the Clean Water Act, including, but not limited to, the...

40 CFR 258.27 - Surface water requirements.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 25 2014-07-01 2014-07-01 false Surface water requirements. 258.27... FOR MUNICIPAL SOLID WASTE LANDFILLS Operating Criteria § 258.27 Surface water requirements. MSWLF... wetlands, that violates any requirements of the Clean Water Act, including, but not limited to, the...

Surface water records of Indiana, 1962

USGS Publications Warehouse

,

1962-01-01

The surface-water records for the 1962 water year for gaging stations, partial-record stations, and miscellaneous sites within the State of Indiana are given in this report. For convenience there are also included records for a few pertinent gaging stations in bordering States. The records were collected and computed by the Water Resources Division of the U.S. Geological Survey, under the direction of Malcolm D. Hale, district engineer, Surface Water Branch. This report marks the beginning of a new method of presenting, annually, basic data on surface-water records by States. Through September 30, 1960, the records of discharge and stage of streams and contents and stage of lakes or reservoirs were published in an annual series of U.S. Geological Survey water-supply papers entitled "Surface Water Supply of the United States." Since 1951 there have been 20 volumes in the series; each volume covered an area whose boundaries coincided with those of certain natural drainage areas. The records in Indiana were contained in Parts 3A, 4 and 5 of that series. Beginning with the 1961 water year, streamflow records and related data will be released by the Geological Survey in annual reports on a State-boundary basis. Distribution of these basic-data reports will be limited and primarily for local needs. The records later will be published in Geological Survey water-supply papers at 5-year intervals. These 5-year water-supply papers will show daily discharge and will be compiled on the same geographical areas previously used for the annual series; however, some of the 14 parts of coterminous United States will be further subdivided.

Surface water records of Indiana, 1963

USGS Publications Warehouse

,

1963-01-01

The surface-water records for the 1963 water year for gaging stations, partial-record stations, and miscellaneous sites within the State of Indiana are given in this report. For convenience there are also included records for a few pertinent gaging stations in bordering States. The records were collected and computed by the Water Resources Division of the U.S. Geological Survey, under the direction of Malcolm D. Hale, district engineer, Surface Water Branch. This report marks the beginning of a new method of presenting, annually, basic data on surface-water records by States. Through September 30, 1960, the records of discharge and stage of streams and contents and stage of lakes or reservoirs were published in an annual series of U.S. Geological Survey water-supply papers entitled "Surface Water Supply of the United States." Since 1951 there have been 20 volumes in the series; each volume covered an area whose boundaries coincided with those of certain natural drainage areas. The records in Indiana were contained in Parts 3A, 4 and 5 of that series. Beginning with the 1961 water year, streamflow records and related data will be released by the Geological Survey in annual reports on a State-boundary basis. Distribution of these basic-data reports will be limited and primarily for local needs. The records later will be published in Geological Survey water-supply papers at 5-year intervals. These 5-year water-supply papers will show daily discharge and will be compiled on the same geographical areas previously used for the annual series; however, some of the 14 parts of coterminous United States will be further subdivided.

Surface water records of Indiana, 1964

USGS Publications Warehouse

,

1964-01-01

The surface-water records for the 1964 water year for gaging stations, partial-record stations, and miscellaneous sites within the State of Indiana are given in this report. For convenience there are also included records for a few pertinent gaging stations in bordering States. The records were collected and computed by the Water Resources Division of the U.S. Geological Survey, under the direction of Malcolm D. Hale, district engineer, Surface Water Branch. This report marks the beginning of a new method of presenting, annually, basic data on surface-water records by States. Through September 30, 1960, the records of discharge and stage of streams and contents and stage of lakes or reservoirs were published in an annual series of U.S. Geological Survey water-supply papers entitled "Surface Water Supply of the United States." Since 1951 there have been 20 volumes in the series; each volume covered an area whose boundaries coincided with those of certain natural drainage areas. The records in Indiana were contained in Parts 3A, 4 and 5 of that series. Beginning with the 1961 water year, streamflow records and related data will be released by the Geological Survey in annual reports on a State-boundary basis. Distribution of these basic-data reports will be limited and primarily for local needs. The records later will be published in Geological Survey water-supply papers at 5-year intervals. These 5-year water-supply papers will show daily discharge and will be compiled on the same geographical areas previously used for the annual series; however, some of the 14 parts of coterminous United States will be further subdivided.

Surface water records of Indiana, 1961

USGS Publications Warehouse

,

1961-01-01

The surface-water records for the 1961 water year for gaging stations, partial-record stations, and miscellaneous sites within the State of Indiana are given in this report. For convenience there are also included records for a few pertinent gaging stations in bordering States. The records were collected and computed by the Water Resources Division of the U.S. Geological Survey, under the direction of Malcolm D. Hale, district engineer, Surface Water Branch. This report marks the beginning of a new method of presenting, annually, basic data on surface-water records by States. Through September 30, 1960, the records of discharge and stage of streams and contents and stage of lakes or reservoirs were published in an annual series of U.S. Geological Survey water-supply papers entitled "Surface Water Supply of the United States." Since 1951 there have been 20 volumes in the series; each volume covered an area whose boundaries coincided with those of certain natural drainage areas. The records in Indiana were contained in Parts 3A, 4 and 5 of that series. Beginning with the 1961 water year, streamflow records and related data will be released by the Geological Survey in annual reports on a State-boundary basis. Distribution of these basic-data reports will be limited and primarily for local needs. The records later will be published in Geological Survey water-supply papers at 5-year intervals. These 5-year water-supply papers will show daily discharge and will be compiled on the same geographical areas previously used for the annual series; however, some of the 14 parts of coterminous United States will be further subdivided.

Variations in the abundance of iron on Mercury's surface from MESSENGER X-Ray Spectrometer observations

NASA Astrophysics Data System (ADS)

Weider, Shoshana Z.; Nittler, Larry R.; Starr, Richard D.; McCoy, Timothy J.; Solomon, Sean C.

2014-06-01

We present measurements of Mercury's surface composition from the analysis of MESSENGER X-Ray Spectrometer data acquired during 55 large solar flares, which each provide a statistically significant detection of Fe X-ray fluorescence. The Fe/Si data display a clear dependence on phase angle, for which the results are empirically corrected. Mercury's surface has a low total abundance of Fe, with a mean Fe/Si ratio of ˜0.06 (equivalent to ˜1.5 wt% Fe). The absolute Fe/Si values are subject to a number of systematic uncertainties, including the phase-angle correction and possible mineral mixing effects. Individual Fe/Si measurements have an intrinsic error of ˜10%. Observed Fe/Si values display small variations (significant at two standard deviations) from the planetary average value across large regions in Mercury's southern hemisphere. Larger differences are observed between measured Fe/Si values from more spatially resolved footprints on volcanic smooth plains deposits in the northern hemisphere and from those in surrounding terrains. Fe is most likely contained as a minor component in sulfide phases (e.g., troilite, niningerite, daubréelite) and as Fe metal, rather than within mafic silicates. Variations in surface reflectance (i.e., differences in overall reflectance and spectral slope) across Mercury are unlikely to be caused by variations in the abundance of Fe.

Measurement of clay surface areas by polyvinylpyrrolidone (PVP) sorption and its use for quantifying illite and smectite abundance

USGS Publications Warehouse

Blum, A.E.; Eberl, D.D.

2004-01-01

A new method has been developed for quantifying smectite abundance by sorbing polyvinylpyrrolidone (PVP) on smectite particles dispersed in aqueous solution. The sorption density of PVP-55K on a wide range of smectites, illites and kaolinites is ~0.99 mg/m2, which corresponds to ~0.72 g of PVP-55K per gram of montmorillonite. Polyvinylpyrrolidone sorption on smectites is independent of layer charge and solution pH. PVP sorption on SiO2, Fe2O3 and ZnO normalized to the BET surface area is similar to the sorption densities on smectites. γ-Al2O3, amorphous Al(OH)3 and gibbsite have no PVP sorption over a wide range of pH, and sorption of PVP by organics is minimal. The insensitivity of PVP sorption densities to mineral layer charge, solution pH and mineral surface charge indicates that PVP sorption is not localized at charged sites, but is controlled by more broadly distributed sorption mechanisms such as Van der Waals’ interactions and/or hydrogen bonding. Smectites have very large surface areas when dispersed as single unit-cell-thick particles (~725 m2/g) and usually dominate the total surface areas of natural samples in which smectites are present. In this case, smectite abundance is directly proportional to PVP sorption. In some cases, however, the accurate quantification of smectite abundance by PVP sorption may require minor corrections for PVP uptake by other phases, principally illite and kaolinite. Quantitative XRD can be combined with PVP uptake measurements to uniquely determine the smectite concentration in such samples.

Integrated Water Flow Model (IWFM), A Tool For Numerically Simulating Linked Groundwater, Surface Water And Land-Surface Hydrologic Processes

NASA Astrophysics Data System (ADS)

Dogrul, E. C.; Brush, C. F.; Kadir, T. N.

2006-12-01

The Integrated Water Flow Model (IWFM) is a comprehensive input-driven application for simulating groundwater flow, surface water flow and land-surface hydrologic processes, and interactions between these processes, developed by the California Department of Water Resources (DWR). IWFM couples a 3-D finite element groundwater flow process and 1-D land surface, lake, stream flow and vertical unsaturated-zone flow processes which are solved simultaneously at each time step. The groundwater flow system is simulated as a multilayer aquifer system with a mixture of confined and unconfined aquifers separated by semiconfining layers. The groundwater flow process can simulate changing aquifer conditions (confined to unconfined and vice versa), subsidence, tile drains, injection wells and pumping wells. The land surface process calculates elemental water budgets for agricultural, urban, riparian and native vegetation classes. Crop water demands are dynamically calculated using distributed soil properties, land use and crop data, and precipitation and evapotranspiration rates. The crop mix can also be automatically modified as a function of pumping lift using logit functions. Surface water diversions and groundwater pumping can each be specified, or can be automatically adjusted at run time to balance water supply with water demand. The land-surface process also routes runoff to streams and deep percolation to the unsaturated zone. Surface water networks are specified as a series of stream nodes (coincident with groundwater nodes) with specified bed elevation, conductance and stage-flow relationships. Stream nodes are linked to form stream reaches. Stream inflows at the model boundary, surface water diversion locations, and one or more surface water deliveries per location are specified. IWFM routes stream flows through the network, calculating groundwater-surface water interactions, accumulating inflows from runoff, and allocating available stream flows to meet specified or

Assessing the relationship between the abundance and properties of microplastics in water and in mussels.

PubMed

Qu, Xiaoyun; Su, Lei; Li, Hengxiang; Liang, Mingzhong; Shi, Huahong

2018-04-15

Microplastic pollution is increasingly becoming a great environmental concern worldwide. Microplastics have been found in many marine organisms as a result of increasing plastic pollution within marine environments. However, the relationship between micoplastics in organisms and their living environment is still relatively poorly understood. In the present study, we investigated microplastic pollution in the water and the mussels (Mytilus edulis, Perna viridis) at 25 sites along the coastal waters of China. We also, for the first time, conducted an exposure experiment in parallel on the same site using M. edulis in the laboratory. A strong positive linear relationship was found between microplastic levels in the water and in the mussels. Fibers were the dominant microplastics. The sizes of microplastics in the mussels were smaller than those in the water. During exposure experiments, the abundance of microbeads was significantly higher than that of fibers, even though the nominal abundance of fibers was eight times that of microbeads. In general, our results supported positive and quantitative correlations of microplastics in mussels and in their surrounding waters and that mussels were more likely to ingest smaller microplastics. Laboratory exposure experiment is a good way to understand the relative impacts of microplastics ingested by marine organisms. However, significant differences in the results between exposure experiments and field investigations indicated that further efforts are needed to simulate the diverse environmentally relevant properties of microplastics. Copyright © 2017 Elsevier B.V. All rights reserved.

Chemical abundances in low surface brightness galaxies: Implications for their evolution

NASA Technical Reports Server (NTRS)

Mcgaugh, S. S.; Bothun, G. D.

1993-01-01

Low Surface Brightness (LSB) galaxies are an important but often neglected part of the galaxy content of the universe. Their importance stems both from the selection effects which cause them to be under-represented in galaxy catalogs, and from what they can tell us about the physical processes of galaxy evolution that has resulted in something other than the traditional Hubble sequence of spirals. An important constraint for any evolutionary model is the present day chemical abundances of LSB disks. Towards this end, spectra for a sample of 75 H 2 regions distributed in 20 LSB disks galaxies were obtained. Structurally, this sample is defined as having B(0) fainter than 23.0 mag arcsec(sup -2) and scale lengths that cluster either around 3 kpc or 10 kpc. In fact, structurally, these galaxies are very similar to the high surface brightness spirals which define the Hubble sequence. Thus, our sample galaxies are not dwarf galaxies but instead have masses comparable to or in excess of the Milky Way. The basic results from these observations are summarized.

Water's Interfacial Hydrogen Bonding Structure Reveals the Effective Strength of Surface-Water Interactions.

PubMed

Shin, Sucheol; Willard, Adam P

2018-06-05

We combine all-atom molecular dynamics simulations with a mean field model of interfacial hydrogen bonding to analyze the effect of surface-water interactions on the structural and energetic properties of the liquid water interface. We show that the molecular structure of water at a weakly interacting ( i.e., hydrophobic) surface is resistant to change unless the strength of surface-water interactions are above a certain threshold. We find that below this threshold water's interfacial structure is homogeneous and insensitive to the details of the disordered surface, however, above this threshold water's interfacial structure is heterogeneous. Despite this heterogeneity, we demonstrate that the equilibrium distribution of molecular orientations can be used to quantify the energetic component of the surface-water interactions that contribute specifically to modifying the interfacial hydrogen bonding network. We identify this specific energetic component as a new measure of hydrophilicity, which we refer to as the intrinsic hydropathy.

Water adsorption on surface-modified cellulose nanocrystals

NASA Astrophysics Data System (ADS)

Wei, Zonghui; Sinko, Robert; Keten, Sinan; Luijten, Erik

Cellulose nanocrystals (CNCs) have attracted much attention as a filler phase for polymer nanocomposites due to their impressive mechanical properties, low cost, and environmental sustainability. Despite their promise for this application, there are still numerous obstacles that prevent optimal performance of CNC-polymer nanocomposites, such as poor filler dispersion and high levels of water absorption. One way to mitigate these negative effects is to modify CNC surfaces. Computational approaches can be utilized to obtain direct insight into the properties of modified CNC surfaces and probe the interactions of CNCs with other materials to facilitate the experimental design of nanocomposites. We use atomistic grand-canonical Monte Carlo simulations to study how surface modification of ion-exchanged sulfated cellulose nanocrystals (Na-CNCs) impacts water adsorption. We find that methyl(triphenyl)phosphonium-exchanged CNCs adsorb less water than Na-CNCs at the same relative humidity, supporting recent experimental dynamic vapor sorption measurements. By characterizing the distribution and configuration of water molecules near the modified CNC surfaces we determine how surface modifications disrupt CNC-water interactions.

An ontology design pattern for surface water features

USGS Publications Warehouse

Sinha, Gaurav; Mark, David; Kolas, Dave; Varanka, Dalia; Romero, Boleslo E.; Feng, Chen-Chieh; Usery, E. Lynn; Liebermann, Joshua; Sorokine, Alexandre

2014-01-01

Surface water is a primary concept of human experience but concepts are captured in cultures and languages in many different ways. Still, many commonalities exist due to the physical basis of many of the properties and categories. An abstract ontology of surface water features based only on those physical properties of landscape features has the best potential for serving as a foundational domain ontology for other more context-dependent ontologies. The Surface Water ontology design pattern was developed both for domain knowledge distillation and to serve as a conceptual building-block for more complex or specialized surface water ontologies. A fundamental distinction is made in this ontology between landscape features that act as containers (e.g., stream channels, basins) and the bodies of water (e.g., rivers, lakes) that occupy those containers. Concave (container) landforms semantics are specified in a Dry module and the semantics of contained bodies of water in a Wet module. The pattern is implemented in OWL, but Description Logic axioms and a detailed explanation is provided in this paper. The OWL ontology will be an important contribution to Semantic Web vocabulary for annotating surface water feature datasets. Also provided is a discussion of why there is a need to complement the pattern with other ontologies, especially the previously developed Surface Network pattern. Finally, the practical value of the pattern in semantic querying of surface water datasets is illustrated through an annotated geospatial dataset and sample queries using the classes of the Surface Water pattern.

Vertical Distribution of Water at Phoenix

NASA Technical Reports Server (NTRS)

Tamppari, L. K.; Lemmon, M. T.

2011-01-01

Phoenix results, combined with coordinated observations from the Mars Reconnaissance Orbiter of the Phoenix lander site, indicate that the water vapor is nonuniform (i.e., not well mixed) up to a calculated cloud condensation level. It is important to understand the mixing profile of water vapor because (a) the assumption of a well-mixed atmosphere up to a cloud condensation level is common in retrievals of column water abundances which are in turn used to understand the seasonal and interannual behavior of water, (b) there is a long history of observations and modeling that conclude both that water vapor is and is not well-mixed, and some studies indicate that the water vapor vertical mixing profile may, in fact, change with season and location, (c) the water vapor in the lowest part of the atmosphere is the reservoir that can exchange with the regolith and higher amounts may have an impact on the surface chemistry, and (d) greater water vapor abundances close to the surface may enhance surface exchange thereby reducing regional transport, which in turn has implications to the net transport of water vapor over seasonal and annual timescales.

Spatial-Temporal Survey and Occupancy-Abundance Modeling To Predict Bacterial Community Dynamics in the Drinking Water Microbiome

PubMed Central

Pinto, Ameet J.; Schroeder, Joanna; Lunn, Mary; Sloan, William

2014-01-01

ABSTRACT Bacterial communities migrate continuously from the drinking water treatment plant through the drinking water distribution system and into our built environment. Understanding bacterial dynamics in the distribution system is critical to ensuring that safe drinking water is being supplied to customers. We present a 15-month survey of bacterial community dynamics in the drinking water system of Ann Arbor, MI. By sampling the water leaving the treatment plant and at nine points in the distribution system, we show that the bacterial community spatial dynamics of distance decay and dispersivity conform to the layout of the drinking water distribution system. However, the patterns in spatial dynamics were weaker than those for the temporal trends, which exhibited seasonal cycling correlating with temperature and source water use patterns and also demonstrated reproducibility on an annual time scale. The temporal trends were driven by two seasonal bacterial clusters consisting of multiple taxa with different networks of association within the larger drinking water bacterial community. Finally, we show that the Ann Arbor data set robustly conforms to previously described interspecific occupancy abundance models that link the relative abundance of a taxon to the frequency of its detection. Relying on these insights, we propose a predictive framework for microbial management in drinking water systems. Further, we recommend that long-term microbial observatories that collect high-resolution, spatially distributed, multiyear time series of community composition and environmental variables be established to enable the development and testing of the predictive framework. PMID:24865557

Infiltration of pesticides in surface water into nearby drinking water supply wells

NASA Astrophysics Data System (ADS)

Malaguerra, F.; Albrechtsen, H.; Binning, P. J.

2010-12-01

Drinking water wells are often placed near streams because streams often overly permeable sediments and the water table is near the surface in valleys, and so pumping costs are reduced. The lowering of the water table by pumping wells can reverse the natural flow from the groundwater to the stream, inducing infiltration of surface water to groundwater and consequently to the drinking water well. Many attenuation processes can take place in the riparian zone, mainly due to mixing, biodegradation and sorption. However, if the water travel time from the surface water to the pumping well is too short, or if the compounds are poorly degradable, contaminants can reach the drinking water well at high concentrations, jeopardizing drinking water quality. Here we developed a reactive transport model to evaluate the risk of contamination of drinking water wells by surface water pollution. The model was validated using data of a tracer experiment in a riparian zone. Three compounds were considered: an older pesticide MCPP (Mecoprop) which is mobile and persistent, glyphosate (Roundup), a new biodegradable and strongly sorbed pesticide, and its degradation product AMPA. Global sensitivity analysis using the method of Morris was employed to identify the dominant model parameters. Results showed that the presence of an aquitard and its characteristics (degree of fracturing and thickness), pollutant properties and well depth are the crucial factors affecting the risk of drinking water well contamination from surface water. Global sensitivity analysis results were compared with rank correlation statistics between pesticide concentrations and geological parameters derived from a comprehensive database of Danish drinking water wells. Aquitard thickness and well depth are the most critical parameters in both the model and observed data.

Seasonal Variation in Abundance and Diversity of Bacterial Methanotrophs in Five Temperate Lakes

PubMed Central

Samad, Md Sainur; Bertilsson, Stefan

2017-01-01

Lakes are significant sources of methane (CH4) to the atmosphere. Within these systems, methanotrophs consume CH4 and act as a potential biofilter mitigating the emission of this potent greenhouse gas. However, it is still not well understood how spatial and temporal variation in environmental parameters influence the abundance, diversity, and community structure of methanotrophs in lakes. To address this gap in knowledge, we collected water samples from three depths (surface, middle, and bottom) representing oxic to suboxic or anoxic zones of five different Swedish lakes in winter (ice-covered) and summer. Methanotroph abundance was determined by quantitative real time polymerase chain reaction and a comparison to environmental variables showed that temperature, season as well as depth, phosphate concentration, dissolved oxygen, and CH4 explained the observed variation in methanotroph abundance. Due to minimal differences in methane concentrations (0.19 and 0.29 μM for summer and winter, respectively), only a weak and even negative correlation was observed between CH4 and methanotrophs, which was possibly due to usage of CH4. Methanotrophs were present at concentrations ranging from 105 to 106 copies/l throughout the oxic (surface) and suboxic/anoxic (bottom) water mass of the lakes, but always contributed less than 1.3% to the total microbial community. Relative methanotroph abundance was significantly higher in winter than in summer and consistently increased with depth in the lakes. Phylogenetic analysis of pmoA genes in two clone libraries from two of the ice-covered lakes (Ekoln and Ramsen) separated the methanotrophs into five distinct clusters of Methylobacter sp. (Type I). Terminal restriction fragment length polymorphism analysis of the pmoA gene further revealed significant differences in methanotrophic communities between lakes as well as between winter and summer while there were no significant differences between water layers. The study provides new

Dynamic Kinetics of Nitrogen Cycle in Groundwater-Surface Water Interaction Zone at Hanford Site

NASA Astrophysics Data System (ADS)

Liu, Y.; Liu, C.; Liu, Y.; Xu, F.; Yan, A.; Shi, L.; Zachara, J. M.; Gao, Y.; Qian, W.; Nelson, W.; Fredrickson, J.; Zhong, L.; Thompson, C.

2015-12-01

Nitrogen cycle carried out by microbes is an important geobiological process that has global implications for carbon and nitrogen cycling and climate change. This presentation describes a study of nitrogen cycle in groundwater-surface water interaction zone (GSIZ) at the US Department of Energy's Hanford Site. Groundwater at Hanford sites has long been documented with nitrate contamination. Nearby Columbia River stage changes of up to 3 m every day because of daily discharge fluctuation from upstream Priest Rapids Dam; resulting an exchange of groundwater and surface water in a short time period. Yet, nitrogen cycle in the GSIZ at Hanford Site remains unclear. Column studies have been used to identify nitrogen metabolism pathways and investigate kinetics of nitrogen cycle in groundwater saturated zone, surface water saturated zone, and GSIZ. Functional gene and protein abundances were determined by qPCR and PRISM-SRM (high-pressure, high-resolution separations coupled with intelligent selection and multiplexing for sensitive selected reaction monitoring) to identify key enzymatic reactions and metabolic pathways of nitrogen cycle. The results showed that dissimilatory nitrate reduction to ammonium (DNRA) competed with denitrification under anaerobic conditions, reducing 30% of NO3- to NH4+, a cation strongly retained on the sediments. As dissolved oxygen intruded the anaerobic zone with river water, NH4+ was oxidized to NO3-, increasing the mobility of NO3-. Multiplicative Monod models were established to describe nitrogen cycle in columns fed with O2 depleted synthetic groundwater and O2 saturated synthetic river water, respectively. The two models were then coupled to predict the dynamic kinetics of nitrogen cycle in GSIZ.

Markedly Enhanced Surface Hydroxyl Groups of TiO2 Nanoparticles with Superior Water-Dispersibility for Photocatalysis

PubMed Central

Wu, Chung-Yi; Tu, Kuan-Ju; Deng, Jin-Pei; Lo, Yu-Shiu; Wu, Chien-Hou

2017-01-01

The benefits of increasing the number of surface hydroxyls on TiO2 nanoparticles (NPs) are known for environmental and energy applications; however, the roles of the hydroxyl groups have not been characterized and distinguished. Herein, TiO2 NPs with abundant surface hydroxyl groups were prepared using commercial titanium dioxide (ST-01) powder pretreated with alkaline hydrogen peroxide. Through this simple treatment, the pure anatase phase was retained with an average crystallite size of 5 nm and the surface hydroxyl group density was enhanced to 12.0 OH/nm2, estimated by thermogravimetric analysis, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy. Especially, this treatment increased the amounts of terminal hydroxyls five- to six-fold, which could raise the isoelectric point and the positive charges on the TiO2 surface in water. The photocatalytic efficiency of the obtained TiO2 NPs was investigated by the photodegradation of sulforhodamine B under visible light irradiation as a function of TiO2 content, pH of solution, and initial dye concentration. The high surface hydroxyl group density of TiO2 NPs can not only enhance water-dispersibility but also promote dye sensitization by generating more hydroxyl radicals. PMID:28772926

Surface-Water Quality-Assurance Plan for the USGS Wisconsin Water Science Center

USGS Publications Warehouse

Garn, H.S.

2007-01-01

This surface-water quality-assurance plan documents the standards, policies, and procedures used by the Wisconsin Water Science Center of the U.S. Geological Survey, Water Resources Discipline, for activities related to the collection, processing, storage, analysis, management, and publication of surface-water data. The roles and responsibilities of Water Science Center personnel in following these policies and procedures including those related to safety and training are presented.

Discharge, water quality, and native fish abundance in the Virgin River, Utah, Nevada, and Arizona, in support of Pah Tempe Springs discharge remediation efforts

USGS Publications Warehouse

Miller, Matthew P.; Lambert, Patrick M.; Hardy, Thomas B.

2014-01-01

Pah Tempe Springs discharge hot, saline, low dissolved-oxygen water to the Virgin River in southwestern Utah, which is transported downstream to Lake Mead and the Colorado River. The dissolved salts in the Virgin River negatively influence the suitability of this water for downstream agricultural, municipal, and industrial use. Therefore, various remediation scenarios to remove the salt load discharged from Pah Tempe Springs to the Virgin River are being considered. One concern about this load removal is the potential to impact the ecology of the Virgin River. Specifically, information is needed regarding possible impacts of Pah Tempe Springs remediation scenarios on the abundance, distribution, and survival of native fish in the Virgin River. Future efforts that aim to quantitatively assess how various remediation scenarios to reduce the load of dissolved salts from Pah Tempe Springs into the Virgin River may influence the abundance, distribution, and survival of native fish will require data on discharge, water quality, and native fish abundance. This report contains organized accessible discharge, water quality, and native fish abundance data sets from the Virgin River, documents the compilation of these data, and discusses approaches for quantifying relations between abiotic physical and chemical conditions, and fish abundance.

Strong Control of Salts on Near Surface Liquid Water Content in a High Polar Desert Indicated by Near Surface Resistivity Mapping with a Helicopter-Borne TEM Sensor, Lower Taylor Valley, Antarctica

NASA Astrophysics Data System (ADS)

Foley, N.; Tulaczyk, S. M.; Auken, E.; Mikucki, J.; Myers, K. F.; Dugan, H.; Doran, P. T.; Virginia, R. A.

2016-12-01

Closed depressions in the Lower Taylor Valley (McMurdo Dry Valleys, Antarctica) have near surface (top 5m) electrical resistivity that is lower by about an order of magnitude than the resistivity of nearby slopes and ridges (100s of ohm-m vs. 1000s). We interpret this spatial pattern as being due to long term concentration of salts carried by liquid water and/or deliquescent vapor fronts. High concentration of salts in the top decimeters to meters beneath the surface may prolong the existence and abundance of liquid water in this otherwise very cold and dry high polar desert. Due to its connections with life and chemical transport, liquid water is a much studied feature in the McMurdo Dry Valleys. This setting can be used as an analogue for similar features on the surface of Mars, where liquid water tracks have been observed and are believed to be controlled by eutectic brines. Our study demonstrates the utility of mapping at a regional scale via helicopter-borne Transient EM. Airborne EM covers more ground and can measure deeper than surface-based measurements, at the expense of resolution. This allows creating valley-scale datasets which could not feasibly be collected on the ground. Our remote measurements complement physical samples that indicate that soluble salts concentrate in certain areas of surface soil where water moves ions and is later removed by evaporation or sublimation. In areas where we measured low resistivity, the integrated liquid water fraction in the top 5m may be a few to several percent by volume, equivalent to a few or several dozens of cm of water layer thickness. This estimate assumes that the interstitial waters have very low resistivity, comparable to seawater or hypersaline brines at freezing (0.2-0.35 ohm-m). If soil water was considerably fresher than this, liquid water content would have to reach dozens of percent throughout the top 5m for bulk resistivities to drop to 100s of ohm-m. We consider the latter case to be unlikely as

Surface-Water Data, Georgia, Water Year 1999

USGS Publications Warehouse

Alhadeff, S. Jack; Landers, Mark N.; McCallum, Brian E.

1999-01-01

Water resources data for the 1999 water year for Georgia consists of records of stage, discharge, and water quality of streams; and the stage and contents of lakes and reservoirs published in one volume in a digital format on a CD-ROM. This volume contains discharge records of 121 gaging stations; stage for 13 gaging stations; stage and contents for 18 lakes and reservoirs; continuous water quality records for 10 stations; and the annual peak stage and annual peak discharge for 75 crest-stage partial-record stations. These data represent that part of the National Water Data System collected by the U.S. Geological Survey and cooperating State and Federal agencies in Georgia. Records of discharge and stage of streams, and contents or stage of lakes and reservoirs were first published in a series of U.S. Geological water-supply papers entitled, 'Surface-Water Supply of the United States.' Through September 30, 1960, these water-supply papers were in an annual series and then in a 5-year series for 1961-65 and 1966-70. Records of chemical quality, water temperature, and suspended sediment were published from 1941 to 1970 in an annual series of water-supply papers entitled, 'Quality of Surface Waters of the United States.' Records of ground-water levels were published from 1935 to 1974 in a series of water-supply papers entitled, 'Ground-Water Levels in the United States.' Water-supply papers may be consulted in the libraries of the principal cities in the United States or may be purchased from the U.S. Geological Survey, Branch of Information Services, Federal Center, Box 25286, Denver, CO 80225. For water years 1961 through 1970, streamflow data were released by the U.S. Geological Survey in annual reports on a State-boundary basis prior to the two 5-year series water-supply papers, which cover this period. The data contained in the water-supply papers are considered the official record. Water-quality records for water years 1964 through 1970 were similarly released

MODFLOW-based coupled surface water routing and groundwater-flow simulation

USGS Publications Warehouse

Hughes, Joseph D.; Langevin, Christian D.; White, Jeremy T.

2015-01-01

In this paper, we present a flexible approach for simulating one- and two-dimensional routing of surface water using a numerical surface water routing (SWR) code implicitly coupled to the groundwater-flow process in MODFLOW. Surface water routing in SWR can be simulated using a diffusive-wave approximation of the Saint-Venant equations and/or a simplified level-pool approach. SWR can account for surface water flow controlled by backwater conditions caused by small water-surface gradients or surface water control structures. A number of typical surface water control structures, such as culverts, weirs, and gates, can be represented, and it is possible to implement operational rules to manage surface water stages and streamflow. The nonlinear system of surface water flow equations formulated in SWR is solved by using Newton methods and direct or iterative solvers. SWR was tested by simulating the (1) Lal axisymmetric overland flow, (2) V-catchment, and (3) modified Pinder-Sauer problems. Simulated results for these problems compare well with other published results and indicate that SWR provides accurate results for surface water-only and coupled surface water/groundwater problems. Results for an application of SWR and MODFLOW to the Snapper Creek area of Miami-Dade County, Florida, USA are also presented and demonstrate the value of coupled surface water and groundwater simulation in managed, low-relief coastal settings.

Herbicide micropollutants in surface, ground and drinking waters within and near the area of Zagreb, Croatia.

PubMed

Fingler, Sanja; Mendaš, G; Dvoršćak, M; Stipičević, S; Vasilić, Ž; Drevenkar, V

2017-04-01

The frequency and mass concentrations of 13 herbicide micropollutants (triazines, phenylureas, chloroacetanilides and trifluralin) were investigated during 2014 in surface, ground and drinking waters in the area of the city of Zagreb and its suburbs. Herbicide compounds were accumulated from water by solid-phase extraction using either octadecylsilica or styrene-divinylbenzene sorbent cartridges and analysed either by high-performance liquid chromatography with UV-diode array detector or gas chromatography with mass spectrometric detection. Atrazine was the most frequently detected herbicide in drinking (84 % of samples) and ground (61 % of samples) waters in mass concentrations of 5 to 68 ng L -1 . It was followed by metolachlor and terbuthylazine, the former being detected in 54 % of drinking (up to 15 ng L -1 ) and 23 % of ground (up to 100 ng L -1 ) waters, and the latter in 45 % of drinking (up to 20 ng L -1 ) and 26 % of ground (up to 25 ng L -1 ) water samples. Acetochlor was the fourth most abundant herbicide in drinking waters, detected in 32 % of samples. Its mass concentrations of 107 to 117 ng L -1 in three tap water samples were the highest of all herbicides measured in the drinking waters. The most frequently (62 % of samples) and highly (up to 887 ng L -1 ) detected herbicide in surface waters was metolachlor, followed by terbuthylazine detected in 49 % of samples in mass concentrations of up to 690 ng L -1 , and atrazine detected in 30 % of samples in mass concentrations of up to 18 ng L -1 . The seasonal variations in herbicide concentrations in surface waters were observed for terbuthylazine, metolachlor, acetochlor, chlortoluron and isoproturon with the highest concentrations measured from April to August.

Investigation of surface water behavior during glaze ice accretion

NASA Technical Reports Server (NTRS)

Hansman, R. John, Jr.; Turnock, Stephen R.

1990-01-01

A series of experimental investigations that focused on isolating the primary factors that control the behavior of unfrozen surface water during glaze ice accretion were conducted. Detailed microvideo observations were made of glaze ice accretions on 2.54 cm diam cylinders in a closed-loop refrigerated wind tunnel. Distinct zones of surface water behavior were observed; a smooth wet zone in the stagnation region with a uniform water film, a rough zone where surface tension effects caused coalescence of surface water into stationary beads, and a zone where surface water ran back as rivulets. The location of the transition from the smooth to the rough zone was found to migrate towards the stagnation point with time. Comparative tests were conducted to study the effect of the substrate thermal and roughness properties on ice accretion. The importance of surface water behavior was evaluated by the addition of a surface tension reducing agent to the icing tunnel water supply, which significantly altered the accreted glaze ice shape. Measurements were made to determine the contact angle behavior of water droplets on ice. A simple multizone modification to current glaze ice accretion models was proposed to include the observed surface roughness behavior.

Microbial Abundance and Diversity at 0.8 to 3.6 Kilometers Beneath the Surface in the Witwatersrand Basin, South Africa

NASA Astrophysics Data System (ADS)

Hall, J.; Rowley, A.; Davidson, M.; Lin, L.; Lippmann, J.; Ward, J.; Slater, G.; Boice, E.; McCuddy, S.; Moser, D.; Onstott, t; Onstott, t

2001-12-01

Access to the Au mines of South Africa has provided us with an unparalleled opportunity to investigate the diversity and abundance of microbes from hydrologically restricted environments at depths up to 3.2 kilometers beneath the surface (kmbls.). Samples of highly pressurized, anaerobic water collected from freshly drilled bore holes into fault or dyke structures ranged in temperature from 32o to 60oC, in salinity from 0.2% to 2.5% and in pH from 7.2 to 10. Flow cytometry analyses of 21 samples amended with a fluorescent DNA stain yielded microbial concentrations ranging from <5{x}103 (detection limit) to 5{x}105 cellsml. The cell concentrations for half of these samples were below the detection limit and those of all the samples collected at 3.2 kmbls. were below detection. Fluorescent, forward and side scatter intensities indicate that the remaining samples contain one or two morphotypes. These values contrast with water samples from subsurface, dammed water pockets or service water where the cell concentrations range from 5{x}104 to 2.5{x}106 cellsml and as many as three morphotypes can be readily distinguished. Thermophilic enrichments suggest that some of these morphotypes are cultivable under conditions that are comparable to the environment. The apparent lack of cells in some of the water samples may reflect a combination of the thermal history of the basin, the origin of the fluid and the isolation of some of the fractures.

Modeling surface-water flow and sediment mobility with the Multi-Dimensional Surface-Water Modeling System (MD_SWMS)

USGS Publications Warehouse

McDonald, Richard; Nelson, Jonathan; Kinzel, Paul; Conaway, Jeffrey S.

2006-01-01

The Multi-Dimensional Surface-Water Modeling System (MD_SWMS) is a Graphical User Interface for surface-water flow and sediment-transport models. The capabilities of MD_SWMS for developing models include: importing raw topography and other ancillary data; building the numerical grid and defining initial and boundary conditions; running simulations; visualizing results; and comparing results with measured data.

Nutrient cycling, connectivity, and free-floating plant abundance in backwater lakes of the Upper Mississippi River

USGS Publications Warehouse

Houser, Jeff N.; Giblin, Shawn M.; James, William F.; Langrehr, H.A.; Rogala, James T.; Sullivan, John F.; Gray, Brian R.

2013-01-01

River eutrophication may cause the formation of dense surface mats of free floating plants (FFP; e.g., duckweeds and filamentous algae) which may adversely affect the ecosystem. We investigated associations among hydraulic connectivity to the channel, nutrient cycling, FFP, submersed aquatic vegetation (SAV), and dissolved oxygen concentration (DO) in ten backwater lakes of the Upper Mississippi River (UMR) that varied in connectivity to the channel. Greater connectivity was associated with higher water column nitrate (NO3-N) concentration, higher rates of sediment phosphorus (P) release, and higher rates of NO3-N flux to the sediments. Rates of sediment P and N (as NH4-N) release were similar to those of eutrophic lakes. Water column nutrient concentrations were high, and FFP tissue was nutrient rich suggesting that the eutrophic condition of the UMR often facilitated abundant FFP. However, tissue nutrient concentrations, and the associations between FFP biomass and water column nutrient concentrations, suggested that nutrients constrained FFP abundance at some sites. FFP abundance was positively associated with SAV abundance and negatively associated with dissolved oxygen concentration. These results illustrate important connections among hydraulic connectivity, nutrient cycling, FFP, SAV, and DO in the backwaters of a large, floodplain river.

Anomalous water dynamics at surfaces and interfaces: synergistic effects of confinement and surface interactions

NASA Astrophysics Data System (ADS)

Biswas, Rajib; Bagchi, Biman

2018-01-01

In nature, water is often found in contact with surfaces that are extended on the scale of molecule size but small on a macroscopic scale. Examples include lipid bilayers and reverse micelles as well as biomolecules like proteins, DNA and zeolites, to name a few. While the presence of surfaces and interfaces interrupts the continuous hydrogen bond network of liquid water, confinement on a mesoscopic scale introduces new features. Even when extended on a molecular scale, natural and biological surfaces often have features (like charge, hydrophobicity) that vary on the scale of the molecular diameter of water. As a result, many new and exotic features, which are not seen in the bulk, appear in the dynamics of water close to the surface. These different behaviors bear the signature of both water-surface interactions and of confinement. In other words, the altered properties are the result of the synergistic effects of surface-water interactions and confinement. Ultrafast spectroscopy, theoretical modeling and computer simulations together form powerful synergistic approaches towards an understanding of the properties of confined water in such systems as nanocavities, reverse micelles (RMs), water inside and outside biomolecules like proteins and DNA, and also between two hydrophobic walls. We shall review the experimental results and place them in the context of theory and simulations. For water confined within RMs, we discuss the possible interference effects propagating from opposite surfaces. Similar interference is found to give rise to an effective attractive force between two hydrophobic surfaces immersed and kept fixed at a separation of d, with the force showing an exponential dependence on this distance. For protein and DNA hydration, we shall examine a multitude of timescales that arise from frustration effects due to the inherent heterogeneity of these surfaces. We pay particular attention to the role of orientational correlations and modification of the

Water at protein surfaces studied with femtosecond nonlinear spectroscopy

NASA Astrophysics Data System (ADS)

Bakker, Huib J.

We report on an investigation of the structure and dynamics of water molecules near protein surfaces with femtosecond nonlinear spectroscopic techniques. We measured the reorientation dynamics of water molecules near the surface of several globular protein surfaces, using polarization-resolved femtosecond infrared spectroscopy. We found that water molecules near the protein surface have a much slower reorientation than water molecules in bulk liquid water. The number of slow water molecules scales scales with the size of the hydrophobic surface of the protein. When we denature the proteins by adding an increasing amount of urea to the protein solution, we observe that the water-exposed surface increases by 50% before the secondary structure of the proteins changes. This finding indicates that protein unfolding starts with the protein structure becoming less tight, thereby allowing water to enter. With surface vibrational sum frequency generation (VSFG) spectroscopy, we studied the structure of water at the surface of antifreeze protein III. The measured VSFG spectra showed the presence of ice-like water layers at the ice-binding site of the protein in aqueous solution, at temperatures well above the freezing point. This ordered ice-like hydration layers at the protein surface likely plays an important role in the specific recognition and binding of anti-freeze protein III to nascent ice crystallites, and thus in its anti-freeze mechanism. This research is supported by the ''Nederlandse organisatie voor Wetenschappelijk Onderzoek (NWO).

Bacterial pathogen gene abundance and relation to recreational water quality at seven Great Lakes beaches

USGS Publications Warehouse

Oster, Ryan J.; Wijesinghe, Rasanthi U.; Fogarty, Lisa Reynolds; Haack, Sheridan K.; Fogarty, Lisa R.; Tucker, Taaja R.; Riley, Stephen

2014-01-01

Quantitative assessment of bacterial pathogens, their geographic variability, and distribution in various matrices at Great Lakes beaches are limited. Quantitative PCR (qPCR) was used to test for genes from E. coli O157:H7 (eaeO157), shiga-toxin producing E. coli (stx2), Campylobacter jejuni (mapA), Shigella spp. (ipaH), and a Salmonella enterica-specific (SE) DNA sequence at seven Great Lakes beaches, in algae, water, and sediment. Overall, detection frequencies were mapA>stx2>ipaH>SE>eaeO157. Results were highly variable among beaches and matrices; some correlations with environmental conditions were observed for mapA, stx2, and ipaH detections. Beach seasonal mean mapA abundance in water was correlated with beach seasonal mean log10E. coli concentration. At one beach, stx2 gene abundance was positively correlated with concurrent daily E. coli concentrations. Concentration distributions for stx2, ipaH, and mapA within algae, sediment, and water were statistically different (Non-Detect and Data Analysis in R). Assuming 10, 50, or 100% of gene copies represented viable and presumably infective cells, a quantitative microbial risk assessment tool developed by Michigan State University indicated a moderate probability of illness for Campylobacter jejuni at the study beaches, especially where recreational water quality criteria were exceeded. Pathogen gene quantification may be useful for beach water quality management.

Low planktic foraminiferal diversity and abundance observed in a spring 2013 west-east Mediterranean Sea plankton tow transect

NASA Astrophysics Data System (ADS)

Mallo, Miguel; Ziveri, Patrizia; Mortyn, P. Graham; Schiebel, Ralf; Grelaud, Michael

2017-05-01

Planktic foraminifera were collected with 150 µm BONGO nets from the upper 200 m water depth at 20 stations across the Mediterranean Sea between 2 May and 2 June 2013. The main aim is to characterize the species distribution and test the covariance between foraminiferal area density (ρA) and seawater carbonate chemistry in a biogeochemical gradient including ultraoligotrophic conditions. Average foraminifera abundances are 1.42 ± 1.43 ind. 10 m-3 (ranging from 0.11 to 5.20 ind. 10 m-3), including 12 morphospecies. Large differences in species assemblages and total abundances are observed between the different Mediterranean sub-basins, with an overall dominance of spinose, symbiont-bearing species indicating oligotrophic conditions. The highest values in absolute abundance are found in the Strait of Gibraltar and the Alboran Sea. The western basin is dominated by Globorotalia inflata and Globigerina bulloides at slightly lower standing stocks than in the eastern basin. In contrast, the planktic foraminiferal assemblage in the warmer, saltier, and more nutrient-limited eastern basin is dominated by Globigerinoides ruber (white). These new results, when combined with previous findings, suggest that temperature-induced surface water stratification and food availability are the main factors controlling foraminiferal distribution. In the oligotrophic and highly alkaline and supersaturated with respect to calcite and aragonite Mediterranean surface water, standing stocks and ρA of G. ruber (white) and G. bulloides are affected by both food availability and seawater carbonate chemistry. Rapid warming increased surface ocean stratification impacting food availability and changes in trophic conditions could be the causes of reduced foraminiferal abundance, diversity, and species-specific changes in planktic foraminiferal calcification.

MODFLOW-Based Coupled Surface Water Routing and Groundwater-Flow Simulation.

PubMed

Hughes, J D; Langevin, C D; White, J T

2015-01-01

In this paper, we present a flexible approach for simulating one- and two-dimensional routing of surface water using a numerical surface water routing (SWR) code implicitly coupled to the groundwater-flow process in MODFLOW. Surface water routing in SWR can be simulated using a diffusive-wave approximation of the Saint-Venant equations and/or a simplified level-pool approach. SWR can account for surface water flow controlled by backwater conditions caused by small water-surface gradients or surface water control structures. A number of typical surface water control structures, such as culverts, weirs, and gates, can be represented, and it is possible to implement operational rules to manage surface water stages and streamflow. The nonlinear system of surface water flow equations formulated in SWR is solved by using Newton methods and direct or iterative solvers. SWR was tested by simulating the (1) Lal axisymmetric overland flow, (2) V-catchment, and (3) modified Pinder-Sauer problems. Simulated results for these problems compare well with other published results and indicate that SWR provides accurate results for surface water-only and coupled surface water/groundwater problems. Results for an application of SWR and MODFLOW to the Snapper Creek area of Miami-Dade County, Florida, USA are also presented and demonstrate the value of coupled surface water and groundwater simulation in managed, low-relief coastal settings. Published 2014. This article is a U.S. Government work and is in the public domain in the USA.

Surface-Water and Ground-Water Resources of Kendall County, Illinois

USGS Publications Warehouse

Kay, Robert T.; Mills, Patrick C.; Hogan, Jennifer L.; Arnold, Terri L.

2005-01-01

Water-supply needs in Kendall County, in northern Illinois, are met exclusively from ground water derived from glacial drift aquifers and bedrock aquifers open to Silurian, Ordovician, and Cambrian System units. As a result of population growth in Kendall County and the surrounding area, water use has increased from about 1.2 million gallons per day in 1957 to more than 5 million gallons per day in 2000. The purpose of this report is to characterize the surface-water and ground-water resources of Kendall County. The report presents a compilation of available information on geology, surface-water and ground-water hydrology, water quality, and water use. The Fox River is the primary surface-water body in Kendall County and is used for both wastewater disposal and as a drinking-water supply upstream of the county. Water from the Fox River requires pretreatment for use as drinking water, but the river is a potentially viable additional source of water for the county. Glacial drift aquifers capable of yielding sufficient water for municipal supply are expected to be present in northern Kendall County, along the Fox River, and in the Newark Valley and its tributaries. Glacial drift aquifers capable of yielding sufficient water for residential supply are present in most of the county, with the exception of the southeastern portion. Volatile organic compounds and select trace metals and pesticides have been detected at low concentrations in glacial drift aquifers near waste-disposal sites. Agricultural-related constituents have been detected infrequently in glacial drift aquifers near agricultural areas. However, on the basis of the available data, widespread, consistent problems with water quality are not apparent in these aquifers. These aquifers are a viable source for additional water supply, but would require further characterization prior to full development. The shallow bedrock aquifer is composed of the sandstone units of the Ancell Group, the Prairie du Chien

Bulk water freezing dynamics on superhydrophobic surfaces

NASA Astrophysics Data System (ADS)

Chavan, S.; Carpenter, J.; Nallapaneni, M.; Chen, J. Y.; Miljkovic, N.

2017-01-01

In this study, we elucidate the mechanisms governing the heat-transfer mediated, non-thermodynamic limited, freezing delay on non-wetting surfaces for a variety of characteristic length scales, Lc (volume/surface area, 3 mm < Lc < 6 mm) using carefully designed freezing experiments in a temperature-controlled, zero-humidity environment on thin water slabs. To probe the effect of surface wettability, we investigated the total time for room temperature water to completely freeze into ice on superhydrophilic ( θaapp→ 0°), hydrophilic (0° < θa < 90°), hydrophobic (90° < θa < 125°), and superhydrophobic ( θaapp→ 180°) surfaces. Our results show that at macroscopic length scales, heat conduction through the bulk water/ice layer dominates the freezing process when compared to heat conduction through the functional coatings or nanoscale gaps at the superhydrophobic substrate-water/ice interface. In order to verify our findings, and to determine when the surface structure thermal resistance approaches the water/ice resistance, we fabricated and tested the additional substrates coated with commercial superhydrophobic spray coatings, showing a monotonic increase in freezing time with coating thickness. The added thermal resistance of thicker coatings was much larger than that of the nanoscale superhydrophobic features, which reduced the droplet heat transfer and increased the total freezing time. Transient finite element method heat transfer simulations of the water slab freezing process were performed to calculate the overall heat transfer coefficient at the substrate-water/ice interface during freezing, and shown to be in the range of 1-2.5 kW/m2K for these experiments. The results shown here suggest that in order to exploit the heat-transfer mediated freezing delay, thicker superhydrophobic coatings must be deposited on the surface, where the coating resistance is comparable to the bulk water/ice conduction resistance.

40 CFR 257.3-3 - Surface water.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 25 2011-07-01 2011-07-01 false Surface water. 257.3-3 Section 257.3-3... and Practices § 257.3-3 Surface water. (a) For purposes of section 4004(a) of the Act, a facility... Water Act, as amended. (b) For purposes of section 4004(a) of the Act, a facility shall not cause a...

40 CFR 257.3-3 - Surface water.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 24 2010-07-01 2010-07-01 false Surface water. 257.3-3 Section 257.3-3... and Practices § 257.3-3 Surface water. (a) For purposes of section 4004(a) of the Act, a facility... Water Act, as amended. (b) For purposes of section 4004(a) of the Act, a facility shall not cause a...

40 CFR 257.3-3 - Surface water.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 26 2012-07-01 2011-07-01 true Surface water. 257.3-3 Section 257.3-3... and Practices § 257.3-3 Surface water. (a) For purposes of section 4004(a) of the Act, a facility... Water Act, as amended. (b) For purposes of section 4004(a) of the Act, a facility shall not cause a...

40 CFR 257.3-3 - Surface water.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 25 2014-07-01 2014-07-01 false Surface water. 257.3-3 Section 257.3-3... and Practices § 257.3-3 Surface water. (a) For purposes of section 4004(a) of the Act, a facility... Water Act, as amended. (b) For purposes of section 4004(a) of the Act, a facility shall not cause a...

40 CFR 257.3-3 - Surface water.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 26 2013-07-01 2013-07-01 false Surface water. 257.3-3 Section 257.3-3... and Practices § 257.3-3 Surface water. (a) For purposes of section 4004(a) of the Act, a facility... Water Act, as amended. (b) For purposes of section 4004(a) of the Act, a facility shall not cause a...

Estimating variations in global surface water storage

NASA Astrophysics Data System (ADS)

Lettenmaier, D. P.

2016-12-01

Arguably, the most dramatic advances attributable to remote sensing in the hydrologic sciences have involved the extension of knowledge about processes and state variables from the scale of field experiments to regions, continents, and the entire Earth. However, despite the availability of information about total terrestrial water storage over large areas provided by the Gravity Recovery and Climate Experiment (GRACE) mission, we still have remarkably little knowledge of the magnitude of freshwater stored at and near the land surface, and its temporal scales of variation. This is especially true with respect to freshwater storage in natural lakes and manmade reservoirs. Estimates of the amount of water that could be stored in artificial reservoirs are in the neighborhood of 15% of the mean annual runoff from the continents or around 7-8000 km3. However, while global reservoir storage was increasing through about 1980 due to filling of new reservoirs constructed in the second half of the 20th century, it is not even known whether aggregate usable reservoir storage is increasing or decreasing, due to sedimentation effects. With the advent of satellite altimeters (mostly intended to measure ocean surface topography and or the surface elevation of glaciers and ice sheets), along with improved methods for estimating space-time variations in the extent of surface waters, new opportunities have arisen to piece together estimates of storage variations of fractions approaching one-half of the global surface water storage, for periods approaching two decades in some cases. Although this ability is nascent, it offers encouragement that, with the launch of the planned Surface Water and Ocean Topography (SWOT) satellite mission in 2020, which has as a specific objective the measurement of surface water variations, climate-scale understanding of this source of variability in Earth's surface water balance may be at hand. I discuss specific examples of the technology and resulting

Shift in the microbial community composition of surface water and sediment along an urban river.

PubMed

Wang, Lan; Zhang, Jing; Li, Huilin; Yang, Hong; Peng, Chao; Peng, Zhengsong; Lu, Lu

2018-06-15

Urban rivers represent a unique ecosystem in which pollution occurs regularly, leading to significantly altered of chemical and biological characteristics of the surface water and sediments. However, the impact of urbanization on the diversity and structure of the river microbial community has not been well documented. As a major tributary of the Yangtze River, the Jialing River flows through many cities. Here, a comprehensive analysis of the spatial microbial distribution in the surface water and sediments in the Nanchong section of Jialing River and its two urban branches was conducted using 16S rRNA gene-based Illumina MiSeq sequencing. The results revealed distinct differences in surface water bacterial composition along the river with a differential distribution of Proteobacteria, Cyanobacteria, Actinobacteria, Bacteroidetes and Acidobacteria (P < 0.05). The bacterial diversity in sediments was significantly higher than their corresponding water samples. Additionally, archaeal communities showed obvious spatial variability in the surface water. The construction of the hydropower station resulted in increased Cyanobacteria abundance in the upstream (32.2%) compared to its downstream (10.3%). Several taxonomic groups of potential fecal indicator bacteria, like Flavobacteria and Bacteroidia, showed an increasing trend in the urban water. PICRUSt metabolic inference analysis revealed a growing number of genes associated with xenobiotic metabolism and nitrogen metabolism in the urban water, indicating that urban discharges might act as the dominant selective force to alter the microbial communities. Redundancy analysis suggested that the microbial community structure was influenced by several environmental factors. TP (P < 0.01) and NO 3 - (P < 0.05), and metals (Zn, Fe) (P < 0.05) were the most significant drivers determining the microbial community composition in the urban river. These results highlight that river microbial communities exhibit

Water resources data for Kansas, water year 1972; Part 1, Surface water records

USGS Publications Warehouse

Thompson, M.L.; Curtis, R. E.

1973-01-01

Surface-water records for the 1972 water year for Kansas, including records of streamflow or reservoir storage at gaging stations and partial-record stations, are given in this report. The locations of the stations are on figures 1 and 2. Records for a few pertinent gaging stations in bordering States also are included. These data represent that part of the National Water Data System collected by the U. S. Geological Survey and cooperating State and Federal agencies in Kansas. The records were collected and computed by the Water Resources Division of the U. S. Geological Survey under the direction of C. W. Lane, district chief. Kansas district personnel who contributed significantly to the collection and preparation of data included in this report were: J. L. Ebling, C. 0. Geiger, K. D. Medina, L. E. Stuliken, C. 0. Peek, J. D. Craig, L. L. Jones, A. T. Klamm, J. P. Marshall, C. W. Kennedy, W. J. Carswell, D. L. Lacock, G. G. Quy II, J. T. Religa, R. D. Thomas, S. V. Bond, S. T. Green, C. G. Sauer, A. B. Evans, A. F. Browning, M. J. Goetz, M. L. Penny, and M. Pabst.Through September 30, 1960, the records of discharge and stage of streams and canals and contents and stage of lakes or reservoirs were published in an annual series of U. S. Geological Survey water-supply papers entitled "Surface Water Supply of the United States."Beginning with the 1961 water year, surface-water records have been released by the Geological Survey in annual reports on a State-boundary basis. Distribution of these reports is limited; they are designed primarily for rapid release of data shortly after the end of the water year to meet local needs. The discharge and reservoir storage records for 1961-65 also have been published in a Geological Survey water-supply paper series entitled "Surface Water Supply of the United States 1961-65."

Water resources data for Kansas, water year 1973; Part 1, Surface water records

USGS Publications Warehouse

Thompson, M.L.; Curtis, R. E.

1974-01-01

Surface-water records for the 1973 water year for Kansas, including records of streamflow or reservoir storage at gaging stations and partial-record stations, are given in this report. The locations of the stations are on figures 1 and 2. Records for a few pertinent gaging stations in bordering States also are included. These data represent that part of the National Water Data System collected by the U. S. Geological Survey and cooperating State and Federal agencies in Kansas. The records were collected and computed by the Water Resources Division of the U. S. Geological Survey under the direction of C. W. Lane, district chief. Kansas district personnel who contributed significantly to the collection and preparation of data included in this report were: J. L. Ebling, C. 0. Geiger, K. D. Medina, C. 0. Peek, J. D. Craig, L. L. Jones, J. P. Marshall, W. J. Carswell, D. L. Lacock, G. G. Quy II, J. T. Religa, R. D. Thomas, S. V. Bond, S. T. Green, C. G. Sauer, L. M. Pope, F. D. Toepfer, A. F. Browning, M. L. Penny, M. Pabst, and L. R. Stringer.Through September 30, 1960, the records of discharge and stage of streams and canals and contents and stage of lakes or reservoirs were published in an annual series of U. S. Geological Survey water-supply papers entitled "Surface Water Supply of the United States."Beginning with the 1961 water year, surface-water records have been released by the Geological Survey in annual reports on a State-boundary basis. Distribution of these reports is limited; they are designed primarily for rapid release of data shortly after the end of the water year to meet local needs. The discharge and reservoir storage records for 1961-65 also have been published in a Geological Survey water-supply paper series entitled "Surface Water Supply of the United States 1961-65."

Mineralogical analyses of surface sediments in the Antarctic Dry Valleys: coordinated analyses of Raman spectra, reflectance spectra and elemental abundances.

PubMed

Bishop, Janice L; Englert, Peter A J; Patel, Shital; Tirsch, Daniela; Roy, Alex J; Koeberl, Christian; Böttger, Ute; Hanke, Franziska; Jaumann, Ralf

2014-12-13

Surface sediments at Lakes Fryxell, Vanda and Brownworth in the Antarctic Dry Valleys (ADV) were investigated as analogues for the cold, dry environment on Mars. Sediments were sampled from regions surrounding the lakes and from the ice cover on top of the lakes. The ADV sediments were studied using Raman spectra of individual grains and reflectance spectra of bulk particulate samples and compared with previous analyses of subsurface and lakebottom sediments. Elemental abundances were coordinated with the spectral data in order to assess trends in sediment alteration. The surface sediments in this study were compared with lakebottom sediments (Bishop JL et al. 2003 Int. J. Astrobiol. 2, 273-287 (doi:10.1017/S1473550403001654)) and samples from soil pits (Englert P et al. 2013 In European Planetary Science Congress, abstract no. 96; Englert P et al. 2014 In 45th Lunar and Planetary Science Conf., abstract no. 1707). Feldspar, quartz and pyroxene are common minerals found in all the sediments. Minor abundances of carbonate, chlorite, actinolite and allophane are also found in the surface sediments, and are similar to minerals found in greater abundance in the lakebottom sediments. Surface sediment formation is dominated by physical processes; a few centimetres below the surface chemical alteration sets in, whereas lakebottom sediments experience biomineralization. Characterizing the mineralogical variations in these samples provides insights into the alteration processes occurring in the ADV and supports understanding alteration in the cold and dry environment on Mars. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

The glass-liquid transition of water on hydrophobic surfaces

NASA Astrophysics Data System (ADS)

Souda, Ryutaro

2008-09-01

Interactions of thin water films with surfaces of graphite and vitrified room-temperature ionic liquid [1-butyl-3-methylimidazolium hexafluorophosphate ([bmim][PF6])] were investigated using time-of-flight secondary ion mass spectrometry as a function of temperature and annealing time to elucidate the glass-liquid transition of water at the molecular level. Surface diffusion of water occurs at temperatures higher than 120K, thereby forming three-dimensional clusters (a two-dimensional layer) on the [bmim][PF6] (graphite) surface. The hydrophobic effect of the surface decreases with increasing coverage of water; the bulklike properties evolve up to 40 ML, as evidenced by the occurrence of film dewetting at around the conventional glass transition temperature (140K). Results also showed that aging is necessary for the water monolayer (a 40 ML water film) to dewet the graphite ([bmim][PF6]) surface. The occurrence of aging is explainable by the successive evolution of two distinct liquids during the glass-liquid transition: low density liquid is followed by supercooled liquid water. The water monolayer on graphite is characterized by the preferred orientation of unpaired OH groups toward the surface; this structure is arrested during the aging time despite the occurrence of surface diffusion. However, the water monolayer formed on the [bmim][PF6] surface agglomerates immediately after the commencement of surface diffusion. The structure of low density liquid tends to be arrested by the attractive interaction with the neighbors.

Phoebe: A Surface Dominated by Water

NASA Astrophysics Data System (ADS)

Fraser, Wesley C.; Brown, Michael E.

2018-07-01

The Saturnian irregular satellite, Phoebe, can be broadly described as a water-rich rock. This object, which presumably originated from the same primordial population shared by the dynamically excited Kuiper Belt Objects (KBOs), has received high-resolution spectral imaging during the Cassini flyby. We present a new analysis of the Visual Infrared Mapping Spectrometer observations of Phoebe, which critically, includes a geometry correction routine that enables pixel-by-pixel mapping of visible and infrared spectral cubes directly onto the Phoebe shape model, even when an image exhibits significant trailing errors. The result of our re-analysis is a successful match of 46 images, producing spectral maps covering the majority of Phoebe’s surface, roughly a third of which is imaged by high-resolution observations (<22 km per pixel resolution). There is no spot on Phoebe’s surface that is absent of water absorption. The regions richest in water are clearly associated with the Jason and south pole impact basins. Phoebe exhibits only three spectral types, and a water–ice concentration that correlates with physical depth and visible albedo. The water-rich and water-poor regions exhibit significantly different crater size frequency distributions and different large crater morphologies. We propose that Phoebe once had a water-poor surface whose water–ice concentration was enhanced by basin-forming impacts that exposed richer subsurface layers. The range of Phoebe’s water–ice absorption spans the same range exhibited by dynamically excited KBOs. The common water–ice absorption depths and primordial origins, and the association of Phoebe’s water-rich regions with its impact basins, suggests the plausible idea that KBOs also originated with water-poor surfaces that were enhanced through stochastic collisional modification.

Concentration and source identification of polycyclic aromatic hydrocarbons and phthalic acid esters in the surface water of the Yangtze River Delta, China.

PubMed

Zhang, Lifei; Dong, Liang; Ren, Lijun; Shi, Shuangxin; Zhou, Li; Zhang, Ting; Huang, Yeru

2012-01-01

The pollution from polycyclic aromatic hydrocarbons (PAHs) and phthalic acid esters (PAEs) in the surface water of the rapidly urbanized Yangtze River Delta region was investigated. Fourteen surface water samples were collected in June 2010. Water samples were liquid-liquid extracted using methylene chloride and analyzed by gas chromatography-mass spectrometry. Concentrations of PAHs and PAEs ranged 12.9-638.1 ng/L and 61-28550 ng/L, respectively. Fluoranthene, naphthalene, pyrene, phenanthrene, di-2-ethylhexyl phthalate, and di-n-butyl phthalate were the most abundant compounds in the samples. The water samples were moderately polluted with benzo[a]pyrene according to China's environmental quality standard for surface water. The two highest concentrations of PAHs and PAEs occurred in samples from Taihu Lake, Wuxi City and the western section of Yangchenghu Lake. Potential sources of pollution at S7 were petroleum combustion and the plastics industry, and at Yangchenghu Lake were petroleum combustion and domestic waste. Pollution in samples from the Beijing-Hangzhou Grand Canal originated from diesel engines. There were no obvious sources of pollution for the other water samples. These results can be used as reference levels for future monitoring programs of pollution from PAHs and PAEs.

Spatio-temporal variations in the diversity and abundance of commercially important Decapoda and Stomatopoda in subtropical Hong Kong waters

NASA Astrophysics Data System (ADS)

Lui, Karen K. Y.; Ng, Jasmine S. S.; Leung, Kenneth M. Y.

2007-05-01

In subtropical Hong Kong, western waters (WW) are strongly influenced by the freshwater input from the Pearl River estuary, especially during summer monsoon, whereas eastern waters (EW) are predominantly influenced by oceanic currents throughout the year. Such hydrographical differences may lead to spatio-temporal differences in biodiversity of benthic communities. This study investigated the diversity and abundance of commercially important decapods and stomatopods in EW (i.e. Tolo Harbour and Channel) and WW (i.e. Tuen Mun and Lantau Island) of Hong Kong using monthly trawl surveys (August 2003-May 2005). In total, 22 decapod and nine stomatopod species were recorded. The penaeid Metapenaeopsis sp. and stomatopod Oratosquillina interrupta were the most abundant and dominant crustaceans in EW and WW, respectively. Both univariate and multivariate analyses showed that WW supported significantly higher abundance, biomass and diversity of crustaceans than EW, although there were significant between-site and within-site variations in community structure. Higher abundance and biomass of crustaceans were recorded in summer than winter. Such spatio-temporal variations could be explained by differences in the hydrography, environmental conditions and anthropogenic impacts between the two areas. Temporal patterns in the abundance-biomass comparison curves and negative W-statistics suggest that the communities have been highly disturbed in both areas, probably due to anthropogenic activities such as bottom trawling and marine pollution.

Surface-Water Conditions in Georgia, Water Year 2005

USGS Publications Warehouse

Painter, Jaime A.; Landers, Mark N.

2007-01-01

INTRODUCTION The U.S. Geological Survey (USGS) Georgia Water Science Center-in cooperation with Federal, State, and local agencies-collected surface-water streamflow, water-quality, and ecological data during the 2005 Water Year (October 1, 2004-September 30, 2005). These data were compiled into layers of an interactive ArcReaderTM published map document (pmf). ArcReaderTM is a product of Environmental Systems Research Institute, Inc (ESRI?). Datasets represented on the interactive map are * continuous daily mean streamflow * continuous daily mean water levels * continuous daily total precipitation * continuous daily water quality (water temperature, specific conductance dissolved oxygen, pH, and turbidity) * noncontinuous peak streamflow * miscellaneous streamflow measurements * lake or reservoir elevation * periodic surface-water quality * periodic ecological data * historical continuous daily mean streamflow discontinued prior to the 2005 water year The map interface provides the ability to identify a station in spatial reference to the political boundaries of the State of Georgia and other features-such as major streams, major roads, and other collection stations. Each station is hyperlinked to a station summary showing seasonal and annual stream characteristics for the current year and for the period of record. For continuous discharge stations, the station summary includes a one page graphical summary page containing five graphs, a station map, and a photograph of the station. The graphs provide a quick overview of the current and period-of-record hydrologic conditions of the station by providing a daily mean discharge graph for the water year, monthly statistics graph for the water year and period of record, an annual mean streamflow graph for the period of record, an annual minimum 7-day average streamflow graph for the period of record, and an annual peak streamflow graph for the period of record. Additionally, data can be accessed through the layer's link

40 CFR 258.27 - Surface water requirements.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 25 2011-07-01 2011-07-01 false Surface water requirements. 258.27 Section 258.27 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) SOLID WASTES CRITERIA FOR MUNICIPAL SOLID WASTE LANDFILLS Operating Criteria § 258.27 Surface water requirements. MSWLF...

A Review of Surface Water Quality Models

PubMed Central

Li, Shibei; Jia, Peng; Qi, Changjun; Ding, Feng

2013-01-01

Surface water quality models can be useful tools to simulate and predict the levels, distributions, and risks of chemical pollutants in a given water body. The modeling results from these models under different pollution scenarios are very important components of environmental impact assessment and can provide a basis and technique support for environmental management agencies to make right decisions. Whether the model results are right or not can impact the reasonability and scientificity of the authorized construct projects and the availability of pollution control measures. We reviewed the development of surface water quality models at three stages and analyzed the suitability, precisions, and methods among different models. Standardization of water quality models can help environmental management agencies guarantee the consistency in application of water quality models for regulatory purposes. We concluded the status of standardization of these models in developed countries and put forward available measures for the standardization of these surface water quality models, especially in developing countries. PMID:23853533

Water Resources Data, Florida, Water Year 2003 Volume 2A: South Florida Surface Water

USGS Publications Warehouse

Price, C.; Woolverton, J.; Overton, K.

2004-01-01

Water resources data for 2003 water year in Florida consists of continuous or daily discharge for 385 streams, periodic discharge for 13 streams, continuous or daily stage for 255 streams, periodic stage for 13 stream, peak discharge for 36 streams, and peak stage for 36 streams, continuous or daily elevations for 13 lakes, periodic elevations for 46 lakes, continuous ground-water levels for 441 wells, periodic ground-water levels for 1227 wells, quality of water data for 133 surface-water sites, and 308 wells. The data for South Florida included continuous or daily discharge for 72 streams, continuous or daily stage for 50 streams, no peak stage discharge for streams, 1 continuous elevation for lake, continuous ground-water levels for 237 wells, periodic ground-water levels for 248 wells, water quality for 25 surface-water sites, and 161 wells. These data represent the National Water Data System records collected by the U.S. Geological Survey and cooperation with local, state, and federal agencies in Florida.

Probing surface hydrogen bonding and dynamics by natural abundance, multidimensional, 17O DNP-NMR spectroscopy

DOE PAGES

Perras, Frederic A.; Chaudhary, Umesh; Slowing, Igor I.; ...

2016-05-06

Dynamic nuclear polarization (DNP)-enhanced solid-state nuclear magnetic resonance (SSNMR) spectroscopy is increasingly being used as a tool for the atomic-level characterization of surface sites. DNP surface-enhanced SSNMR spectroscopy of materials has, however, been limited to studying relatively receptive nuclei, and the particularly rare 17O nuclide, which is of great interest for materials science, has not been utilized. We demonstrate that advanced 17O SSNMR experiments can be performed on surface species at natural isotopic abundance using DNP. We use 17O DNP surface-enhanced 2D SSNMR to measure 17O{ 1H} HETCOR spectra as well as dipolar oscillations on a series of thermally treatedmore » mesoporous silica nanoparticle samples having different pore diameters. These experiments allow for a nonintrusive and unambiguous characterization of hydrogen bonding and dynamics at the surface of the material; no other single experiment can give such details about the interactions at the surface. Lastly, our data show that, upon drying, strongly hydrogen-bonded surface silanols, whose motions are greatly restricted by the interaction when compared to lone silanols, are selectively dehydroxylated.« less

Surface, Bulk, and Interface: Rational Design of Hematite Architecture toward Efficient Photo-Electrochemical Water Splitting.

PubMed

Li, Chengcheng; Luo, Zhibin; Wang, Tuo; Gong, Jinlong

2018-05-11

Collecting and storing solar energy to hydrogen fuel through a photo-electrochemical (PEC) cell provides a clean and renewable pathway for future energy demands. Having earth-abundance, low biotoxicity, robustness, and an ideal n-type band position, hematite (α-Fe 2 O 3 ), the most common natural form of iron oxide, has occupied the research hotspot for decades. Here, a close look into recent progress of hematite photoanodes for PEC water splitting is provided. Effective approaches are introduced, such as cocatalysts loading and surface passivation layer deposition, to improve the hematite surface reaction in thermodynamics and kinetics. Second, typical methods for enhancing light absorption and accelerating charge transport in hematite bulk are reviewed, concentrating upon doping and nanostructuring. Third, the back contact between hematite and substrate, which affects interface states and electron transfer, is deliberated. In addition, perspectives on the key challenges and future prospects for the development of hematite photoelectrodes for PEC water splitting are given. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Polarimetric thermal emission from periodic water surfaces

NASA Technical Reports Server (NTRS)

Yueh, S. H.; Nghiem, S. V.; Kwok, R.; Wilson, W. J.; Li, F. K.; Johnson, J. T.; Kong, J. A.

1993-01-01

Experimental results and theoretical calculations are presented to study the polarimetric emission from water surfaces with directional features. For our ground-based Ku-band radiometer measurements, a water pool was constructed on the roof of a building in the Jet Propulsion Laboratory, and a fiberglass surface with periodic corrugations in one direction was impressed on the top of the water surface to create a stationary water surface underneath it. It is observed that the measured Stokes parameters of corrugated fiberglass-covered water surfaces are functions of azimuth angles and agree very well with the theoretical calculations. The theory, after being verified by the experimental data, was then used to calculate the Stokes parameters of periodic surfaces without fiberglass surface layer and with rms height of the order of wind-generated water ripples. The magnitudes of the azimuthal variation of the calculated emissivities at horizontal and vertical polarizations corresponding to the first two Stokes parameters are found to be comparable to the values measured by airborne radiometers and SSM/I. In addition, the third Stokes parameter not shown in the literature is seen to have approximately twice the magnitude of the azimuth variation of either T(sub h) or T(sub v), which may make it more sensitive to the row direction, while less susceptive to noises because the atmospheric and system noises tend to be unpolarized and are expected to be cancelled out when the third Stokes parameter is derived as the difference of two or three power measurements, as indicated by another experiment carried out at a swimming pool with complicated surroundings. The results indicate that passive polarimetry is a potential technology in the remote sensing of ocean wind vector which is a crucial component in the understanding of global climate change. Issues related to the application of microwave passive polarimetry to ocean wind are also discussed.

Large accumulation of micro-sized synthetic polymer particles in the sea surface microlayer.

PubMed

Song, Young Kyoung; Hong, Sang Hee; Jang, Mi; Kang, Jung-Hoon; Kwon, Oh Youn; Han, Gi Myung; Shim, Won Joon

2014-08-19

Determining the exact abundance of microplastics on the sea surface can be susceptible to the sampling method used. The sea surface microlayer (SML) can accumulate light plastic particles, but this has not yet been sampled. The abundance of microplastics in the SML was evaluated off the southern coast of Korea. The SML sampling method was then compared to bulk surface water filtering, a hand net (50 μm mesh), and a Manta trawl net (330 μm mesh). The mean abundances were in the order of SML water > hand net > bulk water > Manta trawl net. Fourier transform infrared spectroscopy (FTIR) identified that alkyds and poly(acrylate/styrene) accounted for 81 and 11%, respectively, of the total polymer content of the SML samples. These polymers originated from paints and the fiber-reinforced plastic (FRP) matrix used on ships. Synthetic polymers from ship coatings should be considered to be a source of microplastics. Selecting a suitable sampling method is crucial for evaluating microplastic pollution.

Long-term change in benthopelagic fish abundance in the abyssal northeast Pacific Ocean.

PubMed

Bailey, D M; Ruhl, H A; Smith, K L

2006-03-01

Food web structure, particularly the relative importance of bottom-up and top-down control of animal abundances, is poorly known for the Earth's largest habitats: the abyssal plains. A unique 15-yr time series of climate, productivity, particulate flux, and abundance of primary consumers (primarily echinoderms) and secondary consumers (fish) was examined to elucidate the response of trophic levels to temporal variation in one another. Towed camera sled deployments in the abyssal northeast Pacific (4100 m water depth) showed that annual mean numbers of the dominant fish genus (Coryphaenoides spp.) more than doubled over the period 1989-2004. Coryphaenoides spp. abundance was significantly correlated with total abundance of mobile epibenthic megafauna (echinoderms), with changes in fish abundance lagging behind changes in the echinoderms. Direct correlations between surface climate and fish abundances, and particulate organic carbon (POC) flux and fish abundances, were insignificant, which may be related to the varied response of the potential prey taxa to climate and POC flux. This study provides a rare opportunity to study the long-term dynamics of an unexploited marine fish population and suggests a dominant role for bottom-up control in this system.

Methane and nitrous oxide cycling microbial communities in soils above septic leach fields: Abundances with depth and correlations with net surface emissions.

PubMed

Fernández-Baca, Cristina P; Truhlar, Allison M; Omar, Amir-Eldin H; Rahm, Brian G; Walter, M Todd; Richardson, Ruth E

2018-05-31

Onsite septic systems use soil microbial communities to treat wastewater, in the process creating potent greenhouse gases (GHGs): methane (CH 4 ) and nitrous oxide (N 2 O). Subsurface soil dispersal systems of septic tank overflow, known as leach fields, are an important part of wastewater treatment and have the potential to contribute significantly to GHG cycling. This study aimed to characterize soil microbial communities associated with leach field systems and quantify the abundance and distribution of microbial populations involved in CH 4 and N 2 O cycling. Functional genes were used to target populations producing and consuming GHGs, specifically methyl coenzyme M reductase (mcrA) and particulate methane monooxygenase (pmoA) for CH 4 and nitric oxide reductase (cnorB) and nitrous oxide reductase (nosZ) for N 2 O. All biomarker genes were found in all soil samples regardless of treatment (leach field, sand filter, or control) or depth (surface or subsurface). In general, biomarker genes were more abundant in surface soils than subsurface soils suggesting the majority of GHG cycling is occurring in near-surface soils. Ratios of production to consumption gene abundances showed a positive relationship with CH 4 emissions (mcrA:pmoA, p < 0.001) but not with N 2 O emission (cnorB:nosZ, p > 0.05). Of the three measured soil parameters (volumetric water content (VWC), temperature, and conductivity), only VWC was significantly correlated to a biomarker gene, mcrA (p = 0.0398) but not pmoA or either of the N 2 O cycling genes (p > 0.05 for cnorB and nosZ). 16S rRNA amplicon library sequencing results revealed soil VWC, CH 4 flux and N 2 O flux together explained 64% of the microbial community diversity between samples. Sequencing of mcrA and pmoA amplicon libraries revealed treatment had little effect on diversity of CH 4 cycling organisms. Overall, these results suggest GHG cycling occurs in all soils regardless of whether or not they are associated

Driving factors behind the distribution of dinocyst composition and abundance in surface sediments in a western Mediterranean coastal lagoon: report from a high resolution mapping study.

PubMed

Fertouna-Bellakhal, Mouna; Dhib, Amel; Béjaoui, Béchir; Turki, Souad; Aleya, Lotfi

2014-07-15

Species composition and abundance of dinocysts in relation to environmental factors were studied at 123 stations of surface sediment in Bizerte Lagoon. Forty-eight dinocyst types were identified, mainly dominated by Brigantidinium simplex, Votadinum spinosum, Alexandrium pseudogonyaulax, Alexandrium catenella, and Lingulodinum machaerophorum along with many round brown cysts and spiny round brown cysts. Cysts ranged from 1276 to 20126 cysts g(-1)dry weight sediment. Significant differences in cyst distribution pattern were recorded among the zones, with a higher cyst abundance occurring in the lagoon's inner areas. Redundancy analyses showed two distinct associations of dinocysts according to location and environmental variables. Ballast water discharges are potential introducers of non-indigenous species, especially harmful ones such as A. catenella and Polysphaeridium zoharyi, with currents playing a pivotal role in cyst distribution. Findings concerning harmful cyst species indicate potential seedbeds for initiation of future blooms and outbreaks of potentially toxic species in the lagoon. Copyright © 2014 Elsevier Ltd. All rights reserved.

Global modelling of Cryptosporidium in surface water

NASA Astrophysics Data System (ADS)

Vermeulen, Lucie; Hofstra, Nynke

2016-04-01

Introduction Waterborne pathogens that cause diarrhoea, such as Cryptosporidium, pose a health risk all over the world. In many regions quantitative information on pathogens in surface water is unavailable. Our main objective is to model Cryptosporidium concentrations in surface waters worldwide. We present the GloWPa-Crypto model and use the model in a scenario analysis. A first exploration of global Cryptosporidium emissions to surface waters has been published by Hofstra et al. (2013). Further work has focused on modelling emissions of Cryptosporidium and Rotavirus to surface waters from human sources (Vermeulen et al 2015, Kiulia et al 2015). A global waterborne pathogen model can provide valuable insights by (1) providing quantitative information on pathogen levels in data-sparse regions, (2) identifying pathogen hotspots, (3) enabling future projections under global change scenarios and (4) supporting decision making. Material and Methods GloWPa-Crypto runs on a monthly time step and represents conditions for approximately the year 2010. The spatial resolution is a 0.5 x 0.5 degree latitude x longitude grid for the world. We use livestock maps (http://livestock.geo-wiki.org/) combined with literature estimates to calculate spatially explicit livestock Cryptosporidium emissions. For human Cryptosporidium emissions, we use UN population estimates, the WHO/UNICEF JMP sanitation country data and literature estimates of wastewater treatment. We combine our emissions model with a river routing model and data from the VIC hydrological model (http://vic.readthedocs.org/en/master/) to calculate concentrations in surface water. Cryptosporidium survival during transport depends on UV radiation and water temperature. We explore pathogen emissions and concentrations in 2050 with the new Shared Socio-economic Pathways (SSPs) 1 and 3. These scenarios describe plausible future trends in demographics, economic development and the degree of global integration. Results and

Distinct Seasonal Patterns of Bacterioplankton Abundance and Dominance of Phyla α-Proteobacteria and Cyanobacteria in Qinhuangdao Coastal Waters Off the Bohai Sea

PubMed Central

He, Yaodong; Sen, Biswarup; Zhou, Shuangyan; Xie, Ningdong; Zhang, Yongfeng; Zhang, Jianle; Wang, Guangyi

2017-01-01

Qinhuangdao coastal waters in northern China are heavily impacted by anthropogenic and natural activities, and we anticipate a direct influence of the impact on the bacterioplankton abundance and diversity inhabiting the adjacent coastal areas. To ascertain the anthropogenic influences, we first evaluated the seasonal abundance patterns and diversity of bacterioplankton in the coastal areas with varied levels of natural and anthropogenic activities and then analyzed the environmental factors which influenced the abundance patterns. Results indicated distinct patterns in bacterioplankton abundance across the warm and cold seasons in all stations. Total bacterial abundance in the stations ranged from 8.67 × 104 to 2.08 × 106 cells/mL and had significant (p < 0.01) positive correlation with total phosphorus (TP), which indicated TP as the key monitoring parameter for anthropogenic impact on nutrients cycling. Proteobacteria and Cyanobacteria were the most abundant phyla in the Qinhuangdao coastal waters. Redundancy analysis revealed significant (p < 0.01) influence of temperature, dissolved oxygen and chlorophyll a on the spatiotemporal abundance pattern of α-Proteobacteria and Cyanobacteria groups. Among the 19 identified bacterioplankton subgroups, α-Proteobacteria (phylum Proteobacteria) was the dominant one followed by Family II (phylum Cyanobacteria), representing 19.1–55.2% and 2.3–54.2% of total sequences, respectively. An inverse relationship (r = -0.82) was observed between the two dominant subgroups, α-Proteobacteria and Family II. A wide range of inverse Simpson index (10.2 to 105) revealed spatial heterogeneity of bacterioplankton diversity likely resulting from the varied anthropogenic and natural influences. Overall, our results suggested that seasonal variations impose substantial influence on shaping bacterioplankton abundance patterns. In addition, the predominance of only a few cosmopolitan species in the Qinhuangdao coastal wasters was

The physics of water droplets on surfaces: exploring the effects of roughness and surface chemistry

NASA Astrophysics Data System (ADS)

Eid, K. F.; Panth, M.; Sommers, A. D.

2018-03-01

This paper explores the fluid property commonly called surface tension, its effect on droplet shape and contact angle, and the major influences of contact angle behaviour (i.e. surface roughness and surface chemistry). Images of water droplets placed on treated copper surfaces are used to measure the contact angles between the droplets and the surface. The surface wettability is manipulated either by growing a self-assembled monolayer on the surface to make it hydrophobic or by changing the surface roughness. The main activities in this experiment, then, are (1) preparing and studying surfaces with different surface wettability and roughness; (2) determining the shape and contact angles of water droplets on these surfaces; and (3) demonstrating the spontaneous motion of water droplets using surface tension gradients.

Bacterioplankton in antarctic ocean waters during late austral winter: abundance, frequency of dividing cells, and estimates of production.

PubMed

Hanson, R B; Shafer, D; Ryan, T; Pope, D H; Lowery, H K

1983-05-01

Bacterioplankton productivity in Antarctic waters of the eastern South Pacific Ocean and Drake Passage was estimated by direct counts and frequency of dividing cells (FDC). Total bacterioplankton assemblages were enumerated by epifluorescent microscopy. The experimentally determined relationship between in situ FDC and the potential instantaneous growth rate constant (mu) is best described by the regression equation ln mu = 0.081 FDC - 3.73. In the eastern South Pacific Ocean, bacterioplankton abundance (2 x 10 to 3.5 x 10 cells per ml) and FDC (11%) were highest at the Polar Front (Antarctic Convergence). North of the Subantarctic Front, abundance and FDC were between 1 x 10 to 2 x 10 cells per ml and 3 to 5%, respectively, and were vertically homogeneous to a depth of 600 m. In Drake Passage, abundance (10 x 10 cells per ml) and FDC (16%) were highest in waters south of the Polar Front and near the sea ice. Subantarctic waters in Drake Passage contained 4 x 10 cells per ml with 4 to 5% FDC. Instantaneous growth rate constants ranged between 0.029 and 0.088 h. Using estimates of potential mu and measured standing stocks, we estimated productivity to range from 0.62 mug of C per liter . day in the eastern South Pacific Ocean to 17.1 mug of C per liter . day in the Drake Passage near the sea ice.

Surface water records of New Mexico, water year 1963

USGS Publications Warehouse

,

1964-01-01

This report is the third in a series presenting, annually, basic data on surface-water records by States. Through September 30, 1960, the records of discharge and stage of streams and contents and stage of lakes or reservoirs were published in an annual series of U. S. Geological Survey water-supply papers entitled "Surface Water Supply of the United States". Since 1951 there have been 20 volumes in the series; each volume covered an area whose boundaries coincided with those of certain natural drainage areas. The records in New Mexico were contained in Parts 7, 8, and 9 of that series. Beginning with the 1961 water year, streamflow records and related data will be released by the Geological Survey in annual reports on a State-boundary basis. Distribution of these basic-data reports will be limited and primarily for local needs. The records later will be published in Geological Survey water-supply papers at 5- year intervals. These 5-year water-supply papers will show daily discharge and will be compiled on the same geographical areas previously used for the annual series; however, some of the 14 parts of conterminous United States will be further subdivided.

Use of Chironomidae (Diptera) Surface-Floating Pupal Exuviae as a Rapid Bioassessment Protocol for Water Bodies.

PubMed

Kranzfelder, Petra; Anderson, Alyssa M; Egan, Alexander T; Mazack, Jane E; Bouchard, R William; Rufer, Moriya M; Ferrington, Leonard C

2015-07-24

Rapid bioassessment protocols using benthic macroinvertebrate assemblages have been successfully used to assess human impacts on water quality. Unfortunately, traditional benthic larval sampling methods, such as the dip-net, can be time-consuming and expensive. An alternative protocol involves collection of Chironomidae surface-floating pupal exuviae (SFPE). Chironomidae is a species-rich family of flies (Diptera) whose immature stages typically occur in aquatic habitats. Adult chironomids emerge from the water, leaving their pupal skins, or exuviae, floating on the water's surface. Exuviae often accumulate along banks or behind obstructions by action of the wind or water current, where they can be collected to assess chironomid diversity and richness. Chironomids can be used as important biological indicators, since some species are more tolerant to pollution than others. Therefore, the relative abundance and species composition of collected SFPE reflect changes in water quality. Here, methods associated with field collection, laboratory processing, slide mounting, and identification of chironomid SFPE are described in detail. Advantages of the SFPE method include minimal disturbance at a sampling area, efficient and economical sample collection and laboratory processing, ease of identification, applicability in nearly all aquatic environments, and a potentially more sensitive measure of ecosystem stress. Limitations include the inability to determine larval microhabitat use and inability to identify pupal exuviae to species if they have not been associated with adult males.

Plastic in surface waters of the Inside Passage and beaches of the Salish Sea in Washington State.

PubMed

Davis, Wallace; Murphy, Anne G

2015-08-15

We summarize results of two independent studies on plastic pollution in the marine environment that overlap in time and space. One study evaluated the abundance of anthropogenic debris on 37 sandy beaches bordering the Salish Sea in Washington State while the other characterized plastic debris in surface waters of the Salish Sea and the Inside Passage to Skagway, Alaska. Both studies concluded that foam, primarily expanded polystyrene was the dominant pollutant. Plastic was found in surface waters the full length of the Inside Passage but was concentrated near harbors. At the wrack line, an average square meter of Washington's 1180km of sandy beaches in the Salish Sea had 61 pieces of anthropogenic debris weighing approximately 5g. The total loading for the entire 1m wide band is estimated to be 72,000,000 pieces and 5.8metric tons. Most anthropogenic debris on beaches is generated within the region. Copyright © 2015 Elsevier Ltd. All rights reserved.

Streaks Of Colored Water Indicate Surface Airflows

NASA Technical Reports Server (NTRS)

Wilcox, Floyd J., Jr.

1994-01-01

Response faster and contamination less than in oil-flow technique. Flowing colored water provides accurate and clean way to reveal flows of air on surfaces of models in wind tunnels. Colored water flows from small orifices in model, forming streak lines under influence of air streaming over surface of model.

Active Sampling Device for Determining Pollutants in Surface and Pore Water - the In Situ Sampler for Biphasic Water Monitoring

NASA Astrophysics Data System (ADS)

Supowit, Samuel D.; Roll, Isaac B.; Dang, Viet D.; Kroll, Kevin J.; Denslow, Nancy D.; Halden, Rolf U.

2016-02-01

We designed and evaluated an active sampling device, using as analytical targets a family of pesticides purported to contribute to honeybee colony collapse disorder. Simultaneous sampling of bulk water and pore water was accomplished using a low-flow, multi-channel pump to deliver water to an array of solid-phase extraction cartridges. Analytes were separated using either liquid or gas chromatography, and analysis was performed using tandem mass spectrometry (MS/MS). Achieved recoveries of fipronil and degradates in water spiked to nominal concentrations of 0.1, 1, and 10 ng/L ranged from 77 ± 12 to 110 ± 18%. Method detection limits (MDLs) were as low as 0.040-0.8 ng/L. Extraction and quantitation of total fiproles at a wastewater-receiving wetland yielded concentrations in surface water and pore water ranging from 9.9 ± 4.6 to 18.1 ± 4.6 ng/L and 9.1 ± 3.0 to 12.6 ± 2.1 ng/L, respectively. Detected concentrations were statistically indistinguishable from those determined by conventional, more laborious techniques (p > 0.2 for the three most abundant fiproles). Aside from offering time-averaged sampling capabilities for two phases simultaneously with picogram-per-liter MDLs, the novel methodology eliminates the need for water and sediment transport via in situ solid phase extraction.

Emission of dimers from a free surface of heated water

NASA Astrophysics Data System (ADS)

Bochkarev, A. A.; Polyakova, V. I.

2014-09-01

The emission rate of water dimers from a free surface and a wetted solid surface in various cases was calculated by a simplified Monte Carlo method with the use of the binding energy of water molecules. The binding energy of water molecules obtained numerically assuming equilibrium between the free surface of water and vapor in the temperature range of 298-438 K corresponds to the coordination number for liquid water equal to 4.956 and is close to the reference value. The calculation results show that as the water temperature increases, the free surface of water and the wetted solid surface become sources of free water dimers. At a temperature of 438 K, the proportion of dimers in the total flow of water molecules on its surface reaches 1%. It is found that in the film boiling mode, the emission rate of dimers decreases with decreasing saturation vapor. Two mechanisms of the emission are described.

The MiMeS survey of magnetism in massive stars: CNO surface abundances of Galactic O stars

NASA Astrophysics Data System (ADS)

Martins, F.; Hervé, A.; Bouret, J.-C.; Marcolino, W.; Wade, G. A.; Neiner, C.; Alecian, E.; Grunhut, J.; Petit, V.

2015-03-01

Context. The evolution of massive stars is still partly unconstrained. Mass, metallicity, mass loss, and rotation are the main drivers of stellar evolution. Binarity and the magnetic field may also significantly affect the fate of massive stars. Aims: Our goal is to investigate the evolution of single O stars in the Galaxy. Methods: For that, we used a sample of 74 objects comprising all luminosity classes and spectral types from O4 to O9.7. We relied on optical spectroscopy obtained in the context of the MiMeS survey of massive stars. We performed spectral modelling with the code CMFGEN. We determined the surface properties of the sample stars, with special emphasis on abundances of carbon, nitrogen, and oxygen. Results: Most of our sample stars have initial masses in the range of 20 to 50 M⊙. We show that nitrogen is more enriched and carbon and oxygen are more depleted in supergiants than in dwarfs, with giants showing intermediate degrees of mixing. CNO abundances are observed in the range of values predicted by nucleosynthesis through the CNO cycle. More massive stars, within a given luminosity class, appear to be more chemically enriched than lower mass stars. We compare our results with predictions of three types of evolutionary models and show that for two sets of models, 80% of our sample can be explained by stellar evolution including rotation. The effect of magnetism on surface abundances is unconstrained. Conclusions: Our study indicates that in the 20-50 M⊙ mass range, the surface chemical abundances of most single O stars in the Galaxy are fairly well accounted for by stellar evolution of rotating stars. Based on observations obtained at 1) the Telescope Bernard Lyot (USR5026) operated by the Observatoire Midi-Pyrénées, Université de Toulouse (Paul Sabatier), Centre National de la Recherche Scientifique of France; 2) at the Canada-France-Hawaii Telescope (CFHT) which is operated by the National Research Council (NRC) of Canada, the Institut

Abundance and Speciation of Water and Sulfate at Gusev Crater and Meridiani Planum

NASA Technical Reports Server (NTRS)

Ming, D. W.; Clark, B. C.; Klingelhoefer, G.; Gellert, R.; Rodionov, D.; Schroeder, C.; deSouza, P.; Yen, A.

2005-01-01

A major science goal of the Mars Exploration Rover (MER) mission is to search for evidence of water activity, and direct mineralogical evidence for aqueous activity has been reported for Meridiani Planum in the form of the iron sulfate hydroxide mineral jarosite and at Gusev crater in the form of goethite. The Spirit and Opportunity rovers have each collected 110+ Moessbauer (MB) and 75+ Alpha Particle X-Ray Spectrometer (APXS) spectra from Gusev crater and Meridiani Planum [1 - 4]. In this abstract, we use mineralogical and elemental data, primarily from the Moessbauer and APXS instruments, to infer the speciation and estimate the abundance of sulfate and water (as either the H2O molecule or the hydroxyl anion) at Gusev crater and Meridiani Planum. Throughout the abstract, we adopt a format for mineral formulas that shows water explicitly rather than the usual practice of structure-based formulas (e.g., for goethite we write Fe2O3xH2O instead of FeOOH).

40 CFR 258.27 - Surface water requirements.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 26 2013-07-01 2013-07-01 false Surface water requirements. 258.27 Section 258.27 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) SOLID WASTES CRITERIA FOR MUNICIPAL SOLID WASTE LANDFILLS Operating Criteria § 258.27 Surface water requirements. MSWLF units shall not: (a) Cause a discharge of...

Desert Beetle-Inspired Superwettable Patterned Surfaces for Water Harvesting.

PubMed

Yu, Zhenwei; Yun, Frank F; Wang, Yanqin; Yao, Li; Dou, Shixue; Liu, Kesong; Jiang, Lei; Wang, Xiaolin

2017-09-01

With the impacts of climate change and impending crisis of clean drinking water, designing functional materials for water harvesting from fog with large water capacity has received much attention in recent years. Nature has evolved different strategies for surviving dry, arid, and xeric conditions. Nature is a school for human beings. In this contribution, inspired by the Stenocara beetle, superhydrophilic/superhydrophobic patterned surfaces are fabricated on the silica poly(dimethylsiloxane) (PDMS)-coated superhydrophobic surfaces using a pulsed laser deposition approach with masks. The resultant samples with patterned wettability demonstrate water-harvesting efficiency in comparison with the silica PDMS-coated superhydrophobic surface and the Pt nanoparticles-coated superhydrophilic surface. The maximum water-harvesting efficiency can reach about 5.3 g cm -2 h -1 . Both the size and the percentage of the Pt-coated superhydrophilic square regions on the patterned surface affect the condensation and coalescence of the water droplet, as well as the final water-harvesting efficiency. The present water-harvesting strategy should provide an avenue to alleviate the water crisis facing mankind in certain arid regions of the world. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Effect of internal tides in the distribution and abundance of microzooplankton in Todos Santos Bay (Ensenada, B.C.)

NASA Astrophysics Data System (ADS)

Valencia, A.; Ibañez Tejero, L.; Ladah, L. B.; Sanchez Velasco, L.; Barton, E. D.

2016-02-01

Microzooplankton trophically connects phytoplankton and zooplanktonic adults. Their distribution and abundance can be directly related to the inherent physical processes in the marine environment. In coastal waters, the distribution and transport of zooplankton, including microzooplankton, can be influenced by high frequency effects such as internal tides. To date, most of the work on planktonic organisms and their interaction with the internal tide has been focused on a few species, such as barnacles, bryozoans and crabs. The aim of this study was to determine the effect of internal tide on the vertical distribution and abundance of microzooplankton, with an emphasis on copepod nauplii, during the evolution of the internal tide in a summer period of strong thermal stratification. Samples were obtained by vertical plankton net (150 micron mesh) hauls at three depth strata (surface, mid-water and bottom in 25 m depth), independently, with a sampling frequency of every hour. The internal tide was detected by rapid changes in temperature and currents observed with thermistor chains and a bottom-mounted upward looking ADCP. Preliminary results shows a strong mode-1 baroclinic tidal signal. The highest abundance of copepod nauplii and microzooplankton biomass occurred at depth, associated with a strong tidal current. The abundance of copepod nauplii and the abundance of microzooplankton biomass in the surface and intermediate strata showed strong vertical displacements between both strata. Data suggest the vertical distribution of microzooplankton can be dependent on the internal tide.

Limits on the Abundance and Burial Depth of Lunar Polar Ice

NASA Technical Reports Server (NTRS)

Elphic, Richard C.; Paige, David A.; Siegler, Matthew A.; Vasavada, Ashwin R.; Teodoro, Luis A.; Eke, Vincent R.

2012-01-01

The Diviner imaging radiometer experiment aboard the Lunar Reconnaissance Orbiter has revealed that surface temperatures in parts of the lunar polar regions are among the lowest in the solar system. Moreover, modeling of these Diviner data using realistic thermal conductivity profiles for lunar regolith and topography-based illumination has been done, with surprising results. Large expanses of circum-polar terrain appear to have near-subsurface temperatures well below 110K, despite receiving episodic low-angle solar illumination [Paige et al., 2010]. These subsurface cold traps could provide areally extensive reservoirs of volatiles. Here we examine the limits to abundance and burial depth of putative volatiles, based on the signature they would create for orbital thermal and epithermal neutrons. Epithermals alone are not sufficient to break the abundance-depth ambiguity, while thermal neutrons provide an independent constraint on the problem. The subsurface cold traps are so large that even modest abundances, well below that inferred from LCROSS observations, would produce readily detectable signatures in the Lunar Prospector neutron spectrometer data [Colaprete et al., 2010]. Specifically, we forward-model the thermal and epithermal neutron leakage flux that would be observed for various ice concentrations, given the depth at which ice stability begins. The LCROSS results point to a water-equivalent hydrogen abundance (WEH) in excess of 10 wt%, when all hydrogenous species are added together (except for H2, detected by LAMP on LRO [Gladstone et al., 2010]). When such an ice abundance is placed in a layer below the stability depth of Paige et al., the epithermal and thermal neutron leakage fluxes are vastly reduced and very much at odds with orbital observations. So clearly an environment that is conducive to cold trapping is necessary but not sufficient for the presence of volatiles such as water. We present the limits on the abundances that are indeed consistent

Water Resources Data, Florida, Water Year 2003, Volume 1A: Northeast Florida Surface Water

USGS Publications Warehouse

,

2004-01-01

Water resources data for the 2003 water year in Florida consist of continuous or daily discharge for 385 streams, periodic discharge for 13 streams, continuous or daily stage for 255 streams, periodic stage for 13 streams, peak stage and discharge for 36 streams; continuous or daily elevations for 13 lakes, periodic elevations for 46 lakes; continuous ground-water levels for 441 wells, periodic ground-water levels for 1,227 wells; quality-of-water data for 133 surface-water sites and 308 wells. The data for northeast Florida include continuous or daily discharge for 138 streams, periodic discharge for 3 streams, continuous or daily stage for 61 streams, periodic stage for 0 streams; peak stage and discharge for 0 streams; continuous or daily elevations for 9 lakes, periodic elevations for 20 lakes; continuous ground water levels for 73 wells, periodic groundwater levels for 543 wells; quality-of-water data for 43 surface-water sites and 115 wells. These data represent the National Water Data System records collected by the U.S. Geological Survey and cooperating local, State and Federal agencies in Florida.

Uncertainties in selected surface water quality data

NASA Astrophysics Data System (ADS)

Rode, M.; Suhr, U.

2006-09-01

Monitoring of surface waters is primarily done to detect the status and trends in water quality and to identify whether observed trends arise form natural or anthropogenic causes. Empirical quality of surface water quality data is rarely certain and knowledge of their uncertainties is essential to assess the reliability of water quality models and their predictions. The objective of this paper is to assess the uncertainties in selected surface water quality data, i.e. suspended sediment, nitrogen fraction, phosphorus fraction, heavy metals and biological compounds. The methodology used to structure the uncertainty is based on the empirical quality of data and the sources of uncertainty in data (van Loon et al., 2006). A literature review was carried out including additional experimental data of the Elbe river. All data of compounds associated with suspended particulate matter have considerable higher sampling uncertainties than soluble concentrations. This is due to high variability's within the cross section of a given river. This variability is positively correlated with total suspended particulate matter concentrations. Sampling location has also considerable effect on the representativeness of a water sample. These sampling uncertainties are highly site specific. The estimation of uncertainty in sampling can only be achieved by taking at least a proportion of samples in duplicates. Compared to sampling uncertainties measurement and analytical uncertainties are much lower. Instrument quality can be stated well suited for field and laboratory situations for all considered constituents. Analytical errors can contribute considerable to the overall uncertainty of surface water quality data. Temporal autocorrelation of surface water quality data is present but literature on general behaviour of water quality compounds is rare. For meso scale river catchments reasonable yearly dissolved load calculations can be achieved using biweekly sample frequencies. For suspended

Hydrophilic directional slippery rough surfaces for water harvesting

PubMed Central

Sun, Nan; Nielsen, Steven O.; Wang, Jing

2018-01-01

Multifunctional surfaces that are favorable for both droplet nucleation and removal are highly desirable for water harvesting applications but are rare. Inspired by the unique functions of pitcher plants and rice leaves, we present a hydrophilic directional slippery rough surface (SRS) that is capable of rapidly nucleating and removing water droplets. Our surfaces consist of nanotextured directional microgrooves in which the nanotextures alone are infused with hydrophilic liquid lubricant. We have shown through molecular dynamics simulations that the physical origin of the efficient droplet nucleation is attributed to the hydrophilic surface functional groups, whereas the rapid droplet removal is due to the significantly reduced droplet pinning of the directional surface structures and slippery interface. We have further demonstrated that the SRS, owing to its large surface area, hydrophilic slippery interface, and directional liquid repellency, outperforms conventional liquid-repellent surfaces in water harvesting applications. PMID:29670942

The Interaction of Water with Solid Surfaces: Fundamental Aspects Revisited

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

Henderson, Michael A.

2002-05-01

Water is perhaps the most important and most pervasive chemical on our planet. The influence of water permeates virtually all areas of biochemical, chemical and physical importance, and is especially evident in phenomena occurring at the interfaces of solid surfaces. Since 1987, when Thiel and Madey (TM) published their review titled "The Interaction of Water with Solid Surfaces: Fundamental Aspects" in Surface Science Reports, there has been considerable progress made in further understanding the fundamental interactions of water with solid surfaces. In the decade and a half, the increased capability of surface scientists to probe at the molecular-level has resultedmore » in more detailed information of the properties of water on progressively more complicated materials and under more stringent conditions. This progress in understanding the properties of water on solid surfaces is evident both in areas for which surface science methodology has traditionally been strong (catalysis and electronic materials) and also in new areas not traditionally studied by surface scientists, such as electrochemistry, photoconversion, mineralogy, adhesion, sensors, atmospheric chemistry, and tribology. Researchers in all these fields grapple with very basic questions regarding the interactions of water with solid surfaces, such as how is water adsorbed, what are the chemical and electrostatic forces that constitute the adsorbed layer, how is water thermally or non-thermally activated, and how do coadsorbates influence these properties of water. The attention paid to these and other fundamental questions in the past decade and a half has been immense. In this review, experimental studies published since the TM review are assimilated with those covered by TM to provide a current picture of the fundamental interactions of water with solid surfaces.« less

A deformable surface model for real-time water drop animation.

PubMed

Zhang, Yizhong; Wang, Huamin; Wang, Shuai; Tong, Yiying; Zhou, Kun

2012-08-01

A water drop behaves differently from a large water body because of its strong viscosity and surface tension under the small scale. Surface tension causes the motion of a water drop to be largely determined by its boundary surface. Meanwhile, viscosity makes the interior of a water drop less relevant to its motion, as the smooth velocity field can be well approximated by an interpolation of the velocity on the boundary. Consequently, we propose a fast deformable surface model to realistically animate water drops and their flowing behaviors on solid surfaces. Our system efficiently simulates water drop motions in a Lagrangian fashion, by reducing 3D fluid dynamics over the whole liquid volume to a deformable surface model. In each time step, the model uses an implicit mean curvature flow operator to produce surface tension effects, a contact angle operator to change droplet shapes on solid surfaces, and a set of mesh connectivity updates to handle topological changes and improve mesh quality over time. Our numerical experiments demonstrate a variety of physically plausible water drop phenomena at a real-time rate, including capillary waves when water drops collide, pinch-off of water jets, and droplets flowing over solid materials. The whole system performs orders-of-magnitude faster than existing simulation approaches that generate comparable water drop effects.

A framework for modeling connections between hydraulics, water surface roughness, and surface reflectance in open channel flows

USGS Publications Warehouse

Legleiter, Carl; Mobley, Curtis D.; Overstreet, Brandon

2017-01-01

This paper introduces a framework for examining connections between the flow field, the texture of the air-water interface, and the reflectance of the water surface and thus evaluating the potential to infer hydraulic information from remotely sensed observations of surface reflectance. We used a spatial correlation model describing water surface topography to illustrate the application of our framework. Nondimensional relations between model parameters and flow intensity were established based on a prior flume study. Expressing the model in the spatial frequency domain allowed us to use an efficient Fourier transform-based algorithm for simulating water surfaces. Realizations for both flume and field settings had water surface slope distributions positively correlated with velocity and water surface roughness. However, most surface facets were gently sloped and thus unlikely to yield strong specular reflections; the model exaggerated the extent of water surface features, leading to underestimation of facet slopes. A ray tracing algorithm indicated that reflectance was greatest when solar and view zenith angles were equal and the sensor scanned toward the Sun to capture specular reflections of the solar beam. Reflected energy was concentrated in a small portion of the sky, but rougher water surfaces reflected rays into a broader range of directions. Our framework facilitates flight planning to avoid surface-reflected radiance while mapping other river attributes, or to maximize this component to exploit relationships between hydraulics and surface reflectance. This initial analysis also highlighted the need for improved models of water surface topography in natural rivers.

Influence of water on the surface of graphene

NASA Astrophysics Data System (ADS)

Kaya, Yunus; Kalkan, Yalçin; Veenhof, Rob

2018-02-01

We have studied how water modifies the surface of graphene and in particular how the surface conductivity of graphene is affected. According to the literature, two types of interactions should be distinguished: physical, where a water molecule remains intact and is located at some distance from the mesh, and chemical, where a water molecule is imbricated in the graphene bond structure. We have developed theoretical models for both types of interactions using the density functional theory (DFT) with the B3LYP hybrid functional combined with the 6-31G(d) basis set. Our calculations show that the surface conductivity of graphene is reduced in the presence of water.

Summary of surface-water quality, ground-water quality, and water withdrawals for the Spirit Lake Reservation, North Dakota

USGS Publications Warehouse

Vining, Kevin C.; Cates, Steven W.

2006-01-01

Available surface-water quality, ground-water quality, and water-withdrawal data for the Spirit Lake Reservation were summarized. The data were collected intermittently from 1948 through 2004 and were compiled from U.S. Geological Survey databases, North Dakota State Water Commission databases, and Spirit Lake Nation tribal agencies. Although the quality of surface water on the reservation generally is satisfactory, no surface-water sources are used for consumable water supplies. Ground water on the reservation is of sufficient quality for most uses. The Tokio and Warwick aquifers have better overall water quality than the Spiritwood aquifer. Water from the Spiritwood aquifer is used mostly for irrigation. The Warwick aquifer provides most of the consumable water for the reservation and for the city of Devils Lake. Annual water withdrawals from the Warwick aquifer by the Spirit Lake Nation ranged from 71 million gallons to 122 million gallons during 2000-04.

An upper limit to the abundance of lightning-produced amino acids in the Jovian water clouds

NASA Astrophysics Data System (ADS)

Bar-Nun, A.; Noy, N.; Podolak, M.

1984-08-01

The effect of excess hydrogen on the synthesis of amino acids by high-temperature shock waves in a hydrogen/methane/ammonia/water vapor mixture was studied experimentally. The energy efficiency results, together with the best estimate of the lightning energy dissipation rate on Jupiter from the Voyage data, were used to calculate an upper limit to the rate of amino acid production by lightning in Jovian water clouds. Using reasonable values for the eddy diffusion coefficients within and below the water clouds, the column abundance of lightning-produced amino acids in the clouds was estimated to be 6.2 x 10 to the -6th cm-am. Hence, concentration of amino acids in water droplets would be 8 x 10 to the -8th mole/liter.

Wetlands inform how climate extremes influence surface water expansion and contraction

USGS Publications Warehouse

Vanderhoof, Melanie; Lane, Charles R.; McManus, Michael L.; Alexander, Laurie C.; Christensen, Jay R.

2018-01-01

Effective monitoring and prediction of flood and drought events requires an improved understanding of how and why surface water expansion and contraction in response to climate varies across space. This paper sought to (1) quantify how interannual patterns of surface water expansion and contraction vary spatially across the Prairie Pothole Region (PPR) and adjacent Northern Prairie (NP) in the United States, and (2) explore how landscape characteristics influence the relationship between climate inputs and surface water dynamics. Due to differences in glacial history, the PPR and NP show distinct patterns in regards to drainage development and wetland density, together providing a diversity of conditions to examine surface water dynamics. We used Landsat imagery to characterize variability in surface water extent across 11 Landsat path/rows representing the PPR and NP (images spanned 1985–2015). The PPR not only experienced a 2.6-fold greater surface water extent under median conditions relative to the NP, but also showed a 3.4-fold greater change in surface water extent between drought and deluge conditions. The relationship between surface water extent and accumulated water availability (precipitation minus potential evapotranspiration) was quantified per watershed and statistically related to variables representing hydrology-related landscape characteristics (e.g., infiltration capacity, surface storage capacity, stream density). To investigate the influence stream connectivity has on the rate at which surface water leaves a given location, we modeled stream-connected and stream-disconnected surface water separately. Stream-connected surface water showed a greater expansion with wetter climatic conditions in landscapes with greater total wetland area, but lower total wetland density. Disconnected surface water showed a greater expansion with wetter climatic conditions in landscapes with higher wetland density, lower infiltration and less anthropogenic

Wetlands inform how climate extremes influence surface water expansion and contraction

NASA Astrophysics Data System (ADS)

Vanderhoof, Melanie K.; Lane, Charles R.; McManus, Michael G.; Alexander, Laurie C.; Christensen, Jay R.

2018-03-01

Effective monitoring and prediction of flood and drought events requires an improved understanding of how and why surface water expansion and contraction in response to climate varies across space. This paper sought to (1) quantify how interannual patterns of surface water expansion and contraction vary spatially across the Prairie Pothole Region (PPR) and adjacent Northern Prairie (NP) in the United States, and (2) explore how landscape characteristics influence the relationship between climate inputs and surface water dynamics. Due to differences in glacial history, the PPR and NP show distinct patterns in regards to drainage development and wetland density, together providing a diversity of conditions to examine surface water dynamics. We used Landsat imagery to characterize variability in surface water extent across 11 Landsat path/rows representing the PPR and NP (images spanned 1985-2015). The PPR not only experienced a 2.6-fold greater surface water extent under median conditions relative to the NP, but also showed a 3.4-fold greater change in surface water extent between drought and deluge conditions. The relationship between surface water extent and accumulated water availability (precipitation minus potential evapotranspiration) was quantified per watershed and statistically related to variables representing hydrology-related landscape characteristics (e.g., infiltration capacity, surface storage capacity, stream density). To investigate the influence stream connectivity has on the rate at which surface water leaves a given location, we modeled stream-connected and stream-disconnected surface water separately. Stream-connected surface water showed a greater expansion with wetter climatic conditions in landscapes with greater total wetland area, but lower total wetland density. Disconnected surface water showed a greater expansion with wetter climatic conditions in landscapes with higher wetland density, lower infiltration and less anthropogenic drainage

Limitations to postfire seedling establishment: The role of seeding technology, water availability, and invasive plant abundance

Treesearch

Jeremy J. James; Tony Svejcar

2010-01-01

Seeding rangeland following wildfire is a central tool managers use to stabilize soils and inhibit the spread of invasive plants. Rates of successful seeding on arid rangeland, however, are low. The objective of this study was to determine the degree to which water availability, invasive plant abundance, and seeding technology influence postfire seedling establishment...

Late Quaternary Palaeoceanographic Changes in Sea Surface Conditions in the Tropical Atlantic

NASA Astrophysics Data System (ADS)

Fischel, Andrea; Seidenkrantz, Marit-Solveig; Kuijpers, Antoon; Nürnberg, Dirk

2013-04-01

Palaeoceanographic changes and the variability in surface water mass hydrography are reconstructed in order to track tropical ocean and climate variability and inter-hemispheric heat exchange through the last 42,000 year BP. Our studies are based on the relative abundance of planktonic foraminifera combined with sea surface temperature approximation based Mg/Ca measurements, XRF scanning and stable oxygen isotope analyses in a 5 m long gravity core Ga307-Win-12GC (17°50.80N, 64°48.7290W), retrieved in the Virgin Island Basin in approx. 3,960 m water depth. The Virgin Island Basin is the deepest part of the Anegada-Jungfern Passage in the northeast Caribbean, one of the most important pathways for water mass exchange between the Central Atlantic and the Caribbean Sea. Due to its bathymetry surface waters as well as deep water mass strata from the northern and southern hemisphere enter the basin, comprising Caribbean Surface Water (CSW), Antarctic Intermediate Water (AAIW), Atlantic Intermediate Water (AIW) and North Atlantic Deep Water (NADW). The planktonic foraminiferal assemblage suggests rather stable sea-surface conditions during the Holocene in the NE Caribbean. However, major changes in the hydrographic setting could be identified within the glacial period. During the glacial period, clear millennial-scale variability in sea-surface temperature and productivity are present. Fluctuations in the relative abundance of Globigerinoides ruber in the sediment core may be correlated to Dansgaard-Oeschger events in the northern North Atlantic. Furthermore an increase in relative abundance of Globorotalia rubescens occurs synchronous with ice rafted debris layers described from the North Atlantic. The faunal changes in the tropical Atlantic may thus be correlated to major climate changes in the North Atlantic, mainly D-O cyclicity as well as Heinrich events. Thus, the synchronous change in water mass distribution and hydrographic cyclicity suggests a possible linkage

Intermittent Surface Water Connectivity: Fill and Spill vs. Fill ...

EPA Pesticide Factsheets

Intermittent surface connectivity can influence aquatic systems, since chemical and biotic movements are often associated with water flow. Although often referred to as fill and spill, wetlands also fill and merge. We examined the effects of these connection types on water levels, ion concentrations, and biotic communities of eight prairie pothole wetlands between 1979 and 2015. Fill and spill caused pulsed surface water connections that were limited to periods following spring snow melt. In contrast, two wetlands connected through fill and merge experienced a nearly continuous, 20-year surface water connection and had completely coincident water levels. Fill and spill led to minimal convergence in dissolved ions and macroinvertebrate composition, while these constituents converged under fill and merge. The primary factor determining difference in responses was duration of the surface water connection between wetland pairs. Our findings suggest that investigations into the effects of intermittent surface water connections should not consider these connections generically, but need to address the specific types of connections. In particular, fill and spill promotes external water exports while fill and merge favors internal storage. The behaviors of such intermittent connections will likely be accentuated under a future with more frequent and severe climate extremes. Under the Safe and Sustainable Water Resources National Program, work is being done to qu

Intermittent Surface Water Connectivity: Fill and Spill Vs. Fill ...

EPA Pesticide Factsheets

Intermittent surface connectivity can influence aquatic systems, since chemical and biotic movements are often associated with water flow. Although often referred to as fill and spill, wetlands also fill and merge. We examined the effects of these connection types on water levels, ion concentrations, and biotic communities of eight prairie pothole wetlands between 1979 and 2015. Fill and spill caused pulsed surface water connections that were limited to periods following spring snow melt. In contrast, two wetlands connected through fill and merge experienced a nearly continuous, 20-year surface water connection and had completely coincident water levels. Fill and spill led to minimal convergence in dissolved ions and macroinvertebrate composition, while these constituents converged under fill and merge. The primary factor determining difference in responses was duration of the surface water connection between wetland pairs. Our findings suggest that investigations into the effects of intermittent surface water connections should not consider these connections generically, but need to address the specific types of connections. In particular, fill and spill promotes external water exports while fill and merge favors internal storage. The behaviors of such intermittent connections will likely be accentuated under a future with more frequent and severe climate extremes. Under the Safe and Sustainable Water Resources National Program, work is being done to qu

Surface wastewater in Samara and their impact on water basins as water supply sources

NASA Astrophysics Data System (ADS)

Strelkov, Alexander; Shuvalov, Mikhail; Gridneva, Marina

2017-10-01

The paper gives an overview of surface wastewater outlets in Samara through the rainwater sewer system into the Saratov water reservoir and the Samara river. The rainwater sewer system in Samara is designed and executed according to a separate scheme, except for the old part of the city, where surface run-off is dumped into the sewer system through siphoned drain. The rainwater system disposes of surface, drainage, industrial clean-contamined waters, emergency and technology discharges from the city’s heat supply and water supply systems. The effluent discharge is carried out by means of separate wastewater outlets into ravines or directly into the Samara river and the Saratov water reservoir without cleaning. The effluent discharge is carried out through the rainwater sewer system with 17 wastewater outlets into the Saratov water reservoir. In the Samara river, surface runoff drainage and clean-contamined water of industrial enterprises is carried out through 14 wastewater outlets. This study emphasizes the demand to arrange effluent discharge and construction of sewage treatment plants to prevent contamination of water objects by surface run-off from residential areas and industrial territories.

Escape jumping by three age-classes of water striders from smooth, wavy and bubbling water surfaces.

PubMed

Ortega-Jimenez, Victor Manuel; von Rabenau, Lisa; Dudley, Robert

2017-08-01

Surface roughness is a ubiquitous phenomenon in both oceanic and terrestrial waters. For insects that live at the air-water interface, such as water striders, non-linear and multi-scale perturbations produce dynamic surface deformations which may impair locomotion. We studied escape jumps of adults, juveniles and first-instar larvae of the water strider Aquarius remigis on smooth, wave-dominated and bubble-dominated water surfaces. Effects of substrate on takeoff jumps were substantial, with significant reductions in takeoff angles, peak translational speeds, attained heights and power expenditure on more perturbed water surfaces. Age effects were similarly pronounced, with the first-instar larvae experiencing the greatest degradation in performance; age-by-treatment effects were also significant for many kinematic variables. Although commonplace in nature, perturbed water surfaces thus have significant and age-dependent effects on water strider locomotion, and on behavior more generally of surface-dwelling insects. © 2017. Published by The Company of Biologists Ltd.

Water Resources Data, Florida, Water Year 2003, Volume 3A: Southwest Florida Surface Water

USGS Publications Warehouse

Kane, R.L.; Fletcher, W.L.

2004-01-01

Water resources data for the 2003 water year in Florida consist of continuous or daily discharges for 385 streams, periodic discharge for 13 streams, continuous daily stage for 255 streams, periodic stage for 13 streams, peak stage for 36 streams and peak discharge for 36 streams, continuous or daily elevations for 13 lakes, periodic elevations for 46 lakes; continuous ground-water levels for 441 wells, periodic ground-water levels for 1,227 wells, and quality-of-water data for 133 surface-water sites and 308 wells. The data for Southwest Florida include records of stage, discharge, and water quality of streams; stage, contents, water quality of lakes and reservoirs, and water levels and water quality of ground-water wells. Volume 3A contains continuous or daily discharge for 103 streams, periodic discharge for 7 streams, continuous or daily stage for 67 streams, periodic stage for 13 streams, peak stage and discharge for 8 streams, continuous or daily elevations for 2 lakes, periodic elevations for 26 lakes, and quality-of-water data for 62 surface-water sites. These data represent the national Water Data System records collected by the U.S. Geological Survey and cooperating local, state, and federal agencies in Florida.

Theoretical Near-IR Spectra for Surface Abundance Studies of Massive Stars

NASA Technical Reports Server (NTRS)

Sonneborn, George; Bouret, J.

2011-01-01

We present initial results of a study of abundance and mass loss properties of O-type stars based on theoretical near-IR spectra computed with state-of-the-art stellar atmosphere models. The James Webb Space Telescope (JWST) will be a powerful tool to obtain high signal-to-noise ratio near-IR (1-5 micron) spectra of massive stars in different environments of local galaxies. Our goal is to analyze model near-IR spectra corresponding to those expected from NIRspec on JWST in order to map the wind properties and surface composition across the parameter range of 0 stars and to determine projected rotational velocities. As a massive star evolves, internal coupling, related mixing, and mass loss impact its intrinsic rotation rate. These three parameters form an intricate loop, where enhanced rotation leads to more mixing which in turn changes the mass loss rate, the latter thus affecting the rotation rate. Since the effects of rotation are expected to be much more pronounced at low metallicity, we pay special attention to models for massive stars in the the Small Magellanic Cloud. This galaxy provides a unique opportunity to probe stellar evolution, and the feedback of massive stars on galactic evol.ution in conditions similar to the epoch of maximal star formation. Plain-Language Abstract: We present initial results of a study of abundance and mass loss properties of massive stars based on theoretical near-infrared (1-5 micron) spectra computed with state-of-the-art stellar atmosphere models. This study is to prepare for observations by the James Webb Space Telescope.

The Mars water cycle

NASA Technical Reports Server (NTRS)

Davies, D. W.

1981-01-01

A model has been developed to test the hypothesis that the observed seasonal and latitudinal distribution of water on Mars is controlled by the sublimation and condensation of surface ice deposits in the Arctic and Antarctic, and the meridional transport of water vapor. Besides reproducing the observed water vapor distribution, the model correctly reproduces the presence of a large permanent ice cap in the Arctic and not in the Antarctic. No permanent ice reservoirs are predicted in the temperate or equatorial zones. Wintertime ice deposits in the Arctic are shown to be the source of the large water vapor abundances observed in the Arctic summertime, and the moderate water vapor abundances in the northern temperate region. Model calculations suggest that a year without dust storms results in very little change in the water vapor distribution. The current water distribution appears to be the equilibrium distribution for present atmospheric conditions.

Pollution patterns and underlying relationships of benzophenone-type UV-filters in wastewater treatment plants and their receiving surface water.

PubMed

Wu, Ming-Hong; Li, Jian; Xu, Gang; Ma, Luo-Dan; Li, Jia-Jun; Li, Jin-Song; Tang, Liang

2018-05-15

The environmental behaviors of emerging pollutants, benzophenone-type UV filters (BP-UV filters) and their derivatives were investigated in four wastewater treatment plants (WWTPs), and their receiving surface waters in Shanghai. The concentration level of selected BP-UV filters in the WWTPs was detected from ngL -1 to μgL -1 . BP (621-951ngL -1 ) and BP-3 (841-1.32 × 10 3 ngL -1 ) were the most abundant and highest detection frequency individuals among the target BP-UV filters in influents, whereas BP (198-400ngL -1 ), BP-4 (93.3-288ngL -1 ) and BP-3 (146-258ngL -1 ) were predominant in effluents. BP-UV filters cannot be completely removed and the total removal efficiency varied widely (-456% to 100%) during the treatment process. It can be inferred that the usage of BP and BP-3 are higher than other BP-UV filters in the study area. The lowest and highest levels were BP-2 (ND-7.66ngL -1 ) and BP-3 (68.5-5.01 × 10 3 ng L -1 ) in the receiving surface water, respectively. Interestingly, the seasonal variation of BP-3 is larger than those of other BP-UV filters in surface water from Shanghai. There is no obvious pollution pattern of BP-UV filters in the surface water from the cosmetic factory area. The correlation analysis of BP-UV filters between WWTPs effluents and nearby downstream water samples suggested that BP-UV filters emitted from some WWTPs might be the main source of receiving surface water. Preliminary risk assessment indicated that the levels of BP-UV filters detected by the effluent posed medium to high risk to fish as well as other aquatic organisms. Copyright © 2018 Elsevier Inc. All rights reserved.

Legionella species diversity and dynamics from surface reservoir to tap water: from cold adaptation to thermophily

PubMed Central

Lesnik, René; Brettar, Ingrid; Höfle, Manfred G

2016-01-01

Water samples of the Drinking Water Supply System (DWSS) of the city of Braunschweig were analysed for its Legionella species composition using genus-specific PCR amplicons and single-strand conformation polymorphism (SSCP) fingerprint analyses based on 16S rRNA genes. These analyses comprised the whole supply chain including raw water, treatment process and large-scale storage, and a seasonal study of finished drinking water sampled monthly from cold and hot tap water. Treatment of raw water had a major impact on Legionella species by reducing their diversity and abundances. The Legionella species composition of the tap water was highly distinct from that of both source waters. In cold water, 8–14 different phylotypes of Legionella (PTLs) were observed per sample with relative abundances ranging from >1% to 53%. In hot water, L. pneumophila was present during all seasons at high relative abundances (8–40%) accompanied by 5–14 other PTLs of which 6 PTLs were in common with cold water. This thermophilic Legionella community, including L. pneumophila, was able to grow in the hot water above 50 °C. Such thermophilic Legionella populations are of general relevance for drinking water management and public health, but also for the ecology and evolution of the genus Legionella. PMID:26528838

Legionella species diversity and dynamics from surface reservoir to tap water: from cold adaptation to thermophily.

PubMed

Lesnik, René; Brettar, Ingrid; Höfle, Manfred G

2016-05-01

Water samples of the Drinking Water Supply System (DWSS) of the city of Braunschweig were analysed for its Legionella species composition using genus-specific PCR amplicons and single-strand conformation polymorphism (SSCP) fingerprint analyses based on 16S rRNA genes. These analyses comprised the whole supply chain including raw water, treatment process and large-scale storage, and a seasonal study of finished drinking water sampled monthly from cold and hot tap water. Treatment of raw water had a major impact on Legionella species by reducing their diversity and abundances. The Legionella species composition of the tap water was highly distinct from that of both source waters. In cold water, 8-14 different phylotypes of Legionella (PTLs) were observed per sample with relative abundances ranging from >1% to 53%. In hot water, L. pneumophila was present during all seasons at high relative abundances (8-40%) accompanied by 5-14 other PTLs of which 6 PTLs were in common with cold water. This thermophilic Legionella community, including L. pneumophila, was able to grow in the hot water above 50 °C. Such thermophilic Legionella populations are of general relevance for drinking water management and public health, but also for the ecology and evolution of the genus Legionella.

A GPU-based mipmapping method for water surface visualization

NASA Astrophysics Data System (ADS)

Li, Hua; Quan, Wei; Xu, Chao; Wu, Yan

2018-03-01

Visualization of water surface is a hot topic in computer graphics. In this paper, we presented a fast method to generate wide range of water surface with good image quality both near and far from the viewpoint. This method utilized uniform mesh and Fractal Perlin noise to model water surface. Mipmapping technology was enforced to the surface textures, which adjust the resolution with respect to the distance from the viewpoint and reduce the computing cost. Lighting effect was computed based on shadow mapping technology, Snell's law and Fresnel term. The render pipeline utilizes a CPU-GPU shared memory structure, which improves the rendering efficiency. Experiment results show that our approach visualizes water surface with good image quality at real-time frame rates performance.

Predicting cyanobacterial abundance, microcystin, and geosmin in a eutrophic drinking-water reservoir using a 14-year dataset

USGS Publications Warehouse

Harris, Ted D.; Graham, Jennifer L.

2017-01-01

Cyanobacterial blooms degrade water quality in drinking water supply reservoirs by producing toxic and taste-and-odor causing secondary metabolites, which ultimately cause public health concerns and lead to increased treatment costs for water utilities. There have been numerous attempts to create models that predict cyanobacteria and their secondary metabolites, most using linear models; however, linear models are limited by assumptions about the data and have had limited success as predictive tools. Thus, lake and reservoir managers need improved modeling techniques that can accurately predict large bloom events that have the highest impact on recreational activities and drinking-water treatment processes. In this study, we compared 12 unique linear and nonlinear regression modeling techniques to predict cyanobacterial abundance and the cyanobacterial secondary metabolites microcystin and geosmin using 14 years of physiochemical water quality data collected from Cheney Reservoir, Kansas. Support vector machine (SVM), random forest (RF), boosted tree (BT), and Cubist modeling techniques were the most predictive of the compared modeling approaches. SVM, RF, and BT modeling techniques were able to successfully predict cyanobacterial abundance, microcystin, and geosmin concentrations <60,000 cells/mL, 2.5 µg/L, and 20 ng/L, respectively. Only Cubist modeling predicted maxima concentrations of cyanobacteria and geosmin; no modeling technique was able to predict maxima microcystin concentrations. Because maxima concentrations are a primary concern for lake and reservoir managers, Cubist modeling may help predict the largest and most noxious concentrations of cyanobacteria and their secondary metabolites.

Surface-Water and Ground-Water Interactions in the Central Everglades, Florida

USGS Publications Warehouse

Harvey, Judson W.; Newlin, Jessica T.; Krest, James M.; Choi, Jungyill; Nemeth, Eric A.; Krupa, Steven L.

2004-01-01

Recharge and discharge are hydrological processes that cause Everglades surface water to be exchanged for subsurface water in the peat soil and the underlying sand and limestone aquifer. These interactions are thought to be important to water budgets, water quality, and ecology in the Everglades. Nonetheless, relatively few studies of surface water and ground water interactions have been conducted in the Everglades, especially in its vast interior areas. This report is a product of a cooperative investigation conducted by the USGS and the South Florida Water Management District (SFWMD) aimed at developing and testing techniques that would provide reliable estimates of recharge and discharge in interior areas of WCA-2A (Water Conservation Area 2A) and several other sites in the central Everglades. The new techniques quantified flow from surface water to the subsurface (recharge) and the opposite (discharge) using (1) Darcy-flux calculations based on measured vertical gradients in hydraulic head and hydraulic conductivity of peat; (2) modeling transport through peat and decay of the naturally occurring isotopes 224Ra and 223Ra (with half-lives of 4 and 11 days, respectively); and (3) modeling transport and decay of naturally occurring and 'bomb-pulse' tritium (half-life of 12.4 years) in ground water. Advantages and disadvantages of each method for quantifying recharge and discharge were compared. In addition, spatial and temporal variability of recharge and discharge were evaluated and controlling factors identified. A final goal was to develop appropriately simplified (that is, time averaged) expressions of the results that will be useful in addressing a broad range of hydrological and ecological problems in the Everglades. Results were compared with existing information about water budgets from the South Florida Water Management Model (SFWMM), a principal tool used by the South Florida Water Management District to plan many of the hydrological aspects of the

Holocene Millennial-scale Surface and Bottom Water Variability, Feni Drift, NE Atlantic Ocean: Foraminiferal Assemblages

NASA Astrophysics Data System (ADS)

Lassen, S. J.; Richter, T. O.; de Stigter, H. C.; van Weering, T. C. E.; de Haas, H.

A high-resolution sediment core from Feni Drift (ENAM9606, 56N 14W, 2543 m wa- ter depth) was investigated for planktonic and benthic foraminiferal assemblages dur- ing the last 12,000 years. During the Preboreal, peak abundances of T.quinqueloba indicate the passage of the Arctic front over the core site. Holocene planktonic foraminiferal assemblages indicate a gradual warming trend of surface water masses punctuated by a major cooling (8,200ky event s.l.), and possibly a slight cooling dur- ing the last 3,000 years. The interval from 10 to 5kyrs shows higher and fluctuating abundances of T.quinqueloba and G.bulloides, which suggest proximity of the subarc- tic front and enhanced spring blooms compared to the upper Holocene. Abundance peaks of N.pachyderma(s) and/or T.quinqueloba indicate a series of millennial-scale cooling events during the entire Holocene, which can be correlated to similar episodes previously described from other locations in the North Atlantic and Norwegian- Greenland Sea. Benthic foraminiferal assemblages indicate a gradual transition from seasonal, spring-bloom related food supply in the Lower Holocene (dominance of the phytodetritus species E.exigua) to possibly lower, but more sustained food supply in the Upper Holocene (dominance of C.obtusa and C.laevigata).

Thermodynamic properties of water solvating biomolecular surfaces

NASA Astrophysics Data System (ADS)

Heyden, Matthias

Changes in the potential energy and entropy of water molecules hydrating biomolecular interfaces play a significant role for biomolecular solubility and association. Free energy perturbation and thermodynamic integration methods allow calculations of free energy differences between two states from simulations. However, these methods are computationally demanding and do not provide insights into individual thermodynamic contributions, i.e. changes in the solvent energy or entropy. Here, we employ methods to spatially resolve distributions of hydration water thermodynamic properties in the vicinity of biomolecular surfaces. This allows direct insights into thermodynamic signatures of the hydration of hydrophobic and hydrophilic solvent accessible sites of proteins and small molecules and comparisons to ideal model surfaces. We correlate dynamic properties of hydration water molecules, i.e. translational and rotational mobility, to their thermodynamics. The latter can be used as a guide to extract thermodynamic information from experimental measurements of site-resolved water dynamics. Further, we study energy-entropy compensations of water at different hydration sites of biomolecular surfaces. This work is supported by the Cluster of Excellence RESOLV (EXC 1069) funded by the Deutsche Forschungsgemeinschaft.

Evaluation of automated urban surface water extraction from Sentinel-2A imagery using different water indices

NASA Astrophysics Data System (ADS)

Yang, Xiucheng; Chen, Li

2017-04-01

Urban surface water is characterized by complex surface continents and small size of water bodies, and the mapping of urban surface water is currently a challenging task. The moderate-resolution remote sensing satellites provide effective ways of monitoring surface water. This study conducts an exploratory evaluation on the performance of the newly available Sentinel-2A multispectral instrument (MSI) imagery for detecting urban surface water. An automatic framework that integrates pixel-level threshold adjustment and object-oriented segmentation is proposed. Based on the automated workflow, different combinations of visible, near infrared, and short-wave infrared bands in Sentinel-2 image via different water indices are first compared. Results show that object-level modified normalized difference water index (MNDWI with band 11) and automated water extraction index are feasible in urban surface water mapping for Sentinel-2 MSI imagery. Moreover, comparative results are obtained utilizing optimal MNDWI from Sentinel-2 and Landsat 8 images, respectively. Consequently, Sentinel-2 MSI achieves the kappa coefficient of 0.92, compared with that of 0.83 from Landsat 8 operational land imager.

Water surface locomotion in tropical canopy ants.

PubMed

Yanoviak, S P; Frederick, D N

2014-06-15

Upon falling onto the water surface, most terrestrial arthropods helplessly struggle and are quickly eaten by aquatic predators. Exceptions to this outcome mostly occur among riparian taxa that escape by walking or swimming at the water surface. Here we document sustained, directional, neustonic locomotion (i.e. surface swimming) in tropical arboreal ants. We dropped 35 species of ants into natural and artificial aquatic settings in Peru and Panama to assess their swimming ability. Ten species showed directed surface swimming at speeds >3 body lengths s(-1), with some swimming at absolute speeds >10 cm s(-1). Ten other species exhibited partial swimming ability characterized by relatively slow but directed movement. The remaining species showed no locomotory control at the surface. The phylogenetic distribution of swimming among ant genera indicates parallel evolution and a trend toward negative association with directed aerial descent behavior. Experiments with workers of Odontomachus bauri showed that they escape from the water by directing their swimming toward dark emergent objects (i.e. skototaxis). Analyses of high-speed video images indicate that Pachycondyla spp. and O. bauri use a modified alternating tripod gait when swimming; they generate thrust at the water surface via synchronized treading and rowing motions of the contralateral fore and mid legs, respectively, while the hind legs provide roll stability. These results expand the list of facultatively neustonic terrestrial taxa to include various species of tropical arboreal ants. © 2014. Published by The Company of Biologists Ltd.

Surface nanobubble nucleation dynamics during water-ethanol exchange

NASA Astrophysics Data System (ADS)

Chan, Chon U.; Ohl, Claus-Dieter

2015-11-01

Water-ethanol exchange has been a promising nucleation method for surface attached nanobubbles since their discovery. In this process, water and ethanol displace each other sequentially on a substrate. As the gas solubility is 36 times higher in ethanol than water, it was suggested that the exchange process leads to transient supersaturation and is responsible for the nanobubble nucleation. In this work, we visualize the nucleation dynamics by controllably mixing water and ethanol. It depicts the temporal evolution of the conventional exchange in a single field of view, detailing the conditions for surface nanobubble nucleation and the flow field that influences their spatial organization. This technique can also pattern surface nanobubbles with variable size distribution.

Seasonal distribution and abundance of cetaceans within French waters- Part II: The Bay of Biscay and the English Channel

NASA Astrophysics Data System (ADS)

Laran, Sophie; Authier, Matthieu; Blanck, Aurélie; Doremus, Ghislain; Falchetto, Hélène; Monestiez, Pascal; Pettex, Emeline; Stephan, Eric; Van Canneyt, Olivier; Ridoux, Vincent

2017-07-01

From the Habitat Directive to the recent Marine Strategy Framework Directive, the conservation status of cetaceans in European water has been of concern for over two decades. In this study, a seasonal comparison of the abundance and distribution of cetaceans was carried out in two contrasted regions of the Eastern North Atlantic, the Bay of Biscay and the English Channel. Estimates were obtained in the two sub-regions (375,000 km²) from large aerial surveys conducted in the winter (November 2011 to February 2012) and in the summer (May to August 2012). The most abundant species encountered in the Channel, the harbour porpoise, displayed strong seasonal variations in its distribution but a stable abundance (18,000 individuals, CV=30%). In the Bay of Biscay, abundance and distribution patterns of common / striped dolphins varied from 285,000 individuals (95% CI: 174,000-481,000) in the winter, preferentially distributed close to the shelf break, to 494,000 individuals (95% CI: 342,000-719,000) distributed beyond the shelf break in summer. Baleen whales also exhibited an increase of their density in summer. Seasonal abundances of bottlenose dolphins were quite stable, with a large number of 'pelagic' encounters offshore in winter. No significant seasonal difference was estimated for pilot whales and sperm whale. These surveys provided baseline estimates to inform policies to be developed, or for existing conservation instruments such as the Habitats Directive. In addition, our results supported the hypothesis of a shift in the summer distributions of some species such as harbour porpoise and minke whale in European waters.

Earth-Abundant Oxygen Evolution Catalysts Coupled onto ZnO Nanowire Arrays for Efficient Photoelectrochemical Water Cleavage

PubMed Central

Jiang, Chaoran; Moniz, Savio J A; Khraisheh, Majeda; Tang, Junwang

2014-01-01

ZnO has long been considered as a model UV-driven photoanode for photoelectrochemical water splitting, but its performance has been limited by fast charge-carrier recombination, extremely poor stability in aqueous solution, and slow kinetics of water oxidation. These issues were addressed by applying a strategy of optimization and passivation of hydrothermally grown 1D ZnO nanowire arrays. The length and diameter of bare ZnO nanowires were optimized by varying the growth time and precursor concentration to achieve optimal photoelectrochemical performance. The addition of earth-abundant cobalt phosphate (Co-Pi) and nickel borate (Ni-B) oxygen evolution catalysts onto ZnO nanowires resulted in substantial cathodic shifts in onset potential to as low as about 0.3 V versus the reversible hydrogen electrode (RHE) for Ni-B/ZnO, for which a maximum photocurrent density of 1.1 mA cm−2 at 0.9 V (vs. RHE) with applied bias photon-to-current efficiency of 0.4 % and an unprecedented near-unity incident photon-to-current efficiency at 370 nm. In addition the potential required for saturated photocurrent was dramatically reduced from 1.6 to 0.9 V versus RHE. Furthermore, the stability of these ZnO nanowires was significantly enhanced by using Ni-B compared to Co-Pi due to its superior chemical robustness, and it thus has additional functionality as a stable protecting layer on the ZnO surface. These remarkable enhancements in both photocatalytic activity and stability directly address the current severe limitations in the use of ZnO-based photoelectrodes for water-splitting applications, and can be applied to other photoanodes for efficient solar-driven fuel synthesis. PMID:25156820

Isolation of heterotrophic diazotrophic bacteria from estuarine surface waters.

PubMed

Farnelid, Hanna; Harder, Jens; Bentzon-Tilia, Mikkel; Riemann, Lasse

2014-10-01

The wide distribution of diverse nitrogenase (nifH) genes affiliated with those of heterotrophic bacteria in marine and estuarine waters indicates ubiquity and an ecologically relevant role for heterotrophic N2 -fixers (diazotrophs) in aquatic nitrogen (N) cycling. However, the lack of cultivated representatives currently precludes an evaluation of their N2 -fixing capacity. In this study, microoxic or anoxic N-free media were inoculated with estuarine Baltic Sea surface water to select for N2 -fixers. After visible growth and isolation of single colonies on oxic plates or in anoxic agar tubes, nifH gene amplicons were obtained from 64 strains and nitrogenase activity, applying the acetylene reduction assay, was confirmed for 40 strains. Two strains, one Gammaproteobacterium affiliated with Pseudomonas and one Alphaproteobacterium affiliated with Rhodopseudomonas were shown to represent established members of the indigenous diazotrophic community in the Baltic Sea, with abundances of up to 7.9 × 10(4) and 4.7 × 10(4)  nifH copies l(-1) respectively. This study reports media for successful isolation of heterotrophic diazotrophs. The applied methodology and the obtained strains will facilitate future identification of factors controlling heterotrophic diazotrophic activity in aquatic environments, which is a prerequisite for understanding and evaluating their ecology and contribution to N cycling at local and regional scales. © 2013 Society for Applied Microbiology and John Wiley & Sons Ltd.

Surface water records of Texas, 1964

USGS Publications Warehouse

,

1965-01-01

The surface-water records for the 1964 water year for gaging stations, partial-record stations, miscellaneous sites, and base-flow studies within the State of Texas are given in this report. For convenience there are also included records for a few pertinent gaging stations in bordering States. The records were collected and computed by the Water Resources Division of the U. S. Geological Survey, under the direction of Trigg Twichell, district chief, Water Resources Division. Through September 30, 1960, the records of discharge and stage of streams and contents and stage of lakes or reservoirs were published in an annual series of U.S. Geological Survey water supply papers, entitled "Surface Water Supply of the United States." Since 1951 there have been 20 volumes in the series; each volume covered an area whose boundaries coincided with those of certain natural drainage areas. The records in Texas were contained in Parts 7 and 8 of that series. Beginning with the 1961 water year, streamflow records and related data have been released by the Geological Survey in annual reports on a State-boundary basis. Distribution of these basic-data reports is limited and primarily for local needs. Records will be published in Geological Survey water-supply papers at 5-year intervals.

Use of Chironomidae (Diptera) Surface-Floating Pupal Exuviae as a Rapid Bioassessment Protocol for Water Bodies

PubMed Central

Kranzfelder, Petra; Anderson, Alyssa M.; Egan, Alexander T.; Mazack, Jane E.; Bouchard,, R. William; Rufer, Moriya M.; Ferrington,, Leonard C.

2015-01-01

Rapid bioassessment protocols using benthic macroinvertebrate assemblages have been successfully used to assess human impacts on water quality. Unfortunately, traditional benthic larval sampling methods, such as the dip-net, can be time-consuming and expensive. An alternative protocol involves collection of Chironomidae surface-floating pupal exuviae (SFPE). Chironomidae is a species-rich family of flies (Diptera) whose immature stages typically occur in aquatic habitats. Adult chironomids emerge from the water, leaving their pupal skins, or exuviae, floating on the water’s surface. Exuviae often accumulate along banks or behind obstructions by action of the wind or water current, where they can be collected to assess chironomid diversity and richness. Chironomids can be used as important biological indicators, since some species are more tolerant to pollution than others. Therefore, the relative abundance and species composition of collected SFPE reflect changes in water quality. Here, methods associated with field collection, laboratory processing, slide mounting, and identification of chironomid SFPE are described in detail. Advantages of the SFPE method include minimal disturbance at a sampling area, efficient and economical sample collection and laboratory processing, ease of identification, applicability in nearly all aquatic environments, and a potentially more sensitive measure of ecosystem stress. Limitations include the inability to determine larval microhabitat use and inability to identify pupal exuviae to species if they have not been associated with adult males. PMID:26274889

Abundance and prevalence of Aedes aegypti immatures and relationships with household water storage in rural areas in southern Viet Nam.

PubMed

Nguyen, Le Anh P; Clements, Archie C A; Jeffery, Jason A L; Yen, Nguyen Thi; Nam, Vu Sinh; Vaughan, Gregory; Shinkfield, Ramon; Kutcher, Simon C; Gatton, Michelle L; Kay, Brian H; Ryan, Peter A

2011-06-01

Since 2000, the Government of Viet Nam has committed to provide rural communities with increased access to safe water through a variety of household water supply schemes (wells, ferrocement tanks and jars) and piped water schemes. One possible, unintended consequence of these schemes is the concomitant increase in water containers that may serve as habitats for dengue mosquito immatures, principally Aedes aegypti. To assess these possible impacts we undertook detailed household surveys of Ae. aegypti immatures, water storage containers and various socioeconomic factors in three rural communes in southern Viet Nam. Positive relationships between the numbers of household water storage containers and the prevalence and abundance of Ae. aegypti immatures were found. Overall, water storage containers accounted for 92-97% and 93-96% of the standing crops of III/IV instars and pupae, respectively. Interestingly, households with higher socioeconomic levels had significantly higher numbers of water storage containers and therefore greater risk of Ae. aegypti infestation. Even after provision of piped water to houses, householders continued to store water in containers and there was no observed decrease in water storage container abundance in these houses, compared to those that relied entirely on stored water. These findings highlight the householders' concerns about the limited availability of water and their strong behavoural patterns associated with storage of water. We conclude that household water storage container availability is a major risk factor for infestation with Ae. aegypti immatures, and that recent investment in rural water supply infrastructure are unlikely to mitigate this risk, at least in the short term.

Dynamics of ice nucleation on water repellent surfaces.

PubMed

Alizadeh, Azar; Yamada, Masako; Li, Ri; Shang, Wen; Otta, Shourya; Zhong, Sheng; Ge, Liehui; Dhinojwala, Ali; Conway, Ken R; Bahadur, Vaibhav; Vinciquerra, A Joseph; Stephens, Brian; Blohm, Margaret L

2012-02-14

Prevention of ice accretion and adhesion on surfaces is relevant to many applications, leading to improved operation safety, increased energy efficiency, and cost reduction. Development of passive nonicing coatings is highly desirable, since current antiicing strategies are energy and cost intensive. Superhydrophobicity has been proposed as a lead passive nonicing strategy, yet the exact mechanism of delayed icing on these surfaces is not clearly understood. In this work, we present an in-depth analysis of ice formation dynamics upon water droplet impact on surfaces with different wettabilities. We experimentally demonstrate that ice nucleation under low-humidity conditions can be delayed through control of surface chemistry and texture. Combining infrared (IR) thermometry and high-speed photography, we observe that the reduction of water-surface contact area on superhydrophobic surfaces plays a dual role in delaying nucleation: first by reducing heat transfer and second by reducing the probability of heterogeneous nucleation at the water-substrate interface. This work also includes an analysis (based on classical nucleation theory) to estimate various homogeneous and heterogeneous nucleation rates in icing situations. The key finding is that ice nucleation delay on superhydrophobic surfaces is more prominent at moderate degrees of supercooling, while closer to the homogeneous nucleation temperature, bulk and air-water interface nucleation effects become equally important. The study presented here offers a comprehensive perspective on the efficacy of textured surfaces for nonicing applications.

Roles of surface water areas for water and solute cycle in Hanoi city, Viet Nam

NASA Astrophysics Data System (ADS)

Hayashi, Takeshi; Kuroda, Keisuke; Do Thuan, An; Tran Thi Viet, Nga; Takizawa, Satoshi

2013-04-01

Hanoi city, the capital of Viet Nam, has developed beside the Red river. Recent rapid urbanization of this city has reduced a large number of natural water areas such as lakes, ponds and canals not only in the central area but the suburban area. Contrary, the urbanization has increased artificial water areas such as pond for fish cultivation and landscaping. On the other hand, the urbanization has induced the inflow of waste water from households and various kinds of factories to these water areas because of delay of sewerage system development. Inflow of the waste water has induced eutrophication and pollution of these water areas. Also, there is a possibility of groundwater pollution by infiltration of polluted surface water. However, the role of these water areas for water cycle and solute transport is not clarified. Therefore, this study focuses on the interaction between surface water areas and groundwater in Hanoi city to evaluate appropriate land development and groundwater resource management. We are carrying out three approaches: a) understanding of geochemical characteristics of surface water and groundwater, b) monitoring of water levels of pond and groundwater, c) sampling of soil and pond sediment. Correlation between d18O and dD of precipitation (after GNIP), the Red River (after GNIR) and the water samples of this study showed that the groundwater is composed of precipitation, the Red River and surface water that has evaporation process. Contribution of the surface water with evaporation process was widely found in the study area. As for groundwater monitoring, the Holocene aquifers at two sites were in unconfined condition in dry season and the groundwater levels in the aquifer continued to increase through rainy season. The results of isotopic analysis and groundwater level monitoring showed that the surface water areas are one of the major groundwater sources. On the other hand, concentrations of dissolved Arsenic (filtered by 0.45um) in the pore

Water resources data for New Mexico, water year 1965; Part 1. Surface water records

USGS Publications Warehouse

,

1966-01-01

The surface-water records for the 1965 water year for gaging stations, partial-record stations, and miscellaneous sites within the State of New Mexico are given in this report. For convenience there are also Included records for a few pertinent gaging stations in bordering States. The records were collected and computed by the Water Resources Division of the U.S. Geological Survey, under the direction of W. E. Hale, District Chief, Water Resources Division. This report is the fifth In a series presenting, annually, basic data on surface-water records by States. Through September 30, 1960, the records of discharge and stage of streams and contents and stage of lakes or reservoirs were published in an annual series of U. S. Geological Survey water-supply papers entitled Surface Water Supply of the United States. Since 1951 there have been 20 volumes in the series; each volume covered an area whose boundaries coincided with those of certain natural drainage areas. The records in New Mexico were contained in Parts 7, 8 and 9 of that series. Beginning with the 1961 water year, streamflow records and related data will be released by the Geological Survey in annual reports on a State-boundary basis. Distribution of these basic-data reports will be limited and primarily for local needs. The records later will be published in Geological Survey water-supply papers at 5~year intervals. These 5-year water-supply papers will show daily discharge and will be compi led On the same geographical areas previously used for the annual series; however, some of the 14 parts of conterminous United States will be further subdivided.

Langmuir circulation inhibits near-surface water turbulence

NASA Astrophysics Data System (ADS)

Schultz, Colin

2012-07-01

In the surface ocean, breaking waves are a major source of air bubbles and turbulent kinetic energy. During the presence of a consistent surface wind, these wave-generated bubbles, along with other surface material like seaweed or foam, can be drawn into long rows along the surface. Driving this organization is Langmuir circulation, a phenomenon in which the wind and waves cause surface waters to rotate helically, moving like a wire wrapped around a pole in the windward direction. These spiral currents oscillate between clockwise and counterclockwise rotations, such that in some places the surface waters are pushed together and in others they are pulled apart. Researchers have previously found that at sites of convergence the bubbles produced by breaking waves are pushed to depths of 15 meters or more, with important implications for air-sea gas mixing and other processes.

Angiotensin II reduces the surface abundance of KV 1.5 channels in arterial myocytes to stimulate vasoconstriction.

PubMed

Kidd, Michael W; Bulley, Simon; Jaggar, Jonathan H

2017-03-01

Several different voltage-dependent K + (K V ) channel isoforms are expressed in arterial smooth muscle cells (myocytes). Vasoconstrictors inhibit K V currents, but the isoform selectivity and mechanisms involved are unclear. We show that angiotensin II (Ang II), a vasoconstrictor, stimulates degradation of K V 1.5, but not K V 2.1, channels through a protein kinase C- and lysosome-dependent mechanism, reducing abundance at the surface of mesenteric artery myocytes. The Ang II-induced decrease in cell surface K V 1.5 channels reduces whole-cell K V 1.5 currents and attenuates K V 1.5 function in pressurized arteries. We describe a mechanism by which Ang II stimulates protein kinase C-dependent K V 1.5 channel degradation, reducing the abundance of functional channels at the myocyte surface. Smooth muscle cells (myocytes) of resistance-size arteries express several different voltage-dependent K + (K V ) channels, including K V 1.5 and K V 2.1, which regulate contractility. Myocyte K V currents are inhibited by vasoconstrictors, including angiotensin II (Ang II), but the mechanisms involved are unclear. Here, we tested the hypothesis that Ang II inhibits K V currents by reducing the plasma membrane abundance of K V channels in myocytes. Angiotensin II (applied for 2 h) reduced surface and total K V 1.5 protein in rat mesenteric arteries. In contrast, Ang II did not alter total or surface K V 2.1, or K V 1.5 or K V 2.1 cellular distribution, measured as the percentage of total protein at the surface. Bisindolylmaleimide (BIM; a protein kinase C blocker), a protein kinase C inhibitory peptide or bafilomycin A (a lysosomal degradation inhibitor) each blocked the Ang II-induced decrease in total and surface K V 1.5. Immunofluorescence also suggested that Ang II reduced surface K V 1.5 protein in isolated myocytes; an effect inhibited by BIM. Arteries were exposed to Ang II or Ang II plus BIM (for 2 h), after which these agents were removed and

Characteristics of pulse corona discharge over water surface

NASA Astrophysics Data System (ADS)

Fujii, Tomio; Arao, Yasushi; Rea, Massimo

2008-12-01

Production of ozone and OH radical is required to advance the plasma chemical reactions in the NOx removal processes for combustion gas treatment. The corona discharge to the water surface is expected to induce the good conditions for the proceeding of the NO oxidation and the NO2 dissolution removal into water. In order to get the fundamental data of the corona discharge over the water surface, the positive and negative V-I characteristics and the ozone production were measured with the multi needle and the saw-edge type of the discharge electrodes. The pulse corona characteristics were also measured with some different waveforms of the applied pulse voltage. The experiments were carried out under the atmospheric pressure and room temperature. Both the DC and the pulse corona to the water surface showed a stable and almost the same V-I characteristics as to plate electrodes though the surface of water was waved by corona wind. The positive streamer corona showed more ozone production than the negative one both in the DC and in the pulse corona.

Review of factors affecting the distribution and abundance of waterfowl in shallow-water habitats of Chesapeake Bay

USGS Publications Warehouse

Perry, M.C.; Deller, A.S.

1996-01-01

Long-term trends of waterfowl populations in Chesapeake Bay demonstrate the importance of shallow-water habitats for waterfowl species. Although recent increases in field feeding by geese and swans lessened the importance of shallow-water areas for these species, most duck species depend almost exclusively on shallow-water habitats. Many factors influenced the distribution and abundance of waterfowl in shallow-water habitats. Habitat degradation resulted in the decline in numbers of most duck species and a change in distribution of some species. Increased numbers of mallards (Anas platyrhynchos) in recent decades probably resulted from release programs conducted by the Maryland Department of Natural Resources and private individuals. Studies of food habits since 1885 showed a decline in submerged-aquatic vegetation in the diet of some species, such as the canvasback (Aythya valisineria ), and an increase in the proportions of invertebrates in the diet. Diversity of food organisms for many waterfowl species has declined. Surveys of vegetation and invertebrates in the Chesapeake Bay generally reflect a degradation of shallow-water habitat. Human population increases in the Chesapeake Bay watershed directly and indirectly affected waterfowl distribution and abundance. The increase of exotic plant and invertebrate species in the bay, in most cases, benefited waterfowl populations. Increased contaminants have reduced the quality and quantity of habitat, although serious attempts to reverse this trend are underway. The use of shallow-water habitats by humans for fishing, hunting, boating, and other recreational and commercial uses reduced the use of shallow-water habitats by waterfowl. Humans can lessen the adverse influences on the valuable shallow-water habitats by restricting human population growth near these habitats and improving the water quality of the bay tributaries. Other affirmative actions that will improve these areas for waterfowl include greater

Thermophoretically driven water droplets on graphene and boron nitride surfaces.

PubMed

Rajegowda, Rakesh; Kannam, Sridhar Kumar; Hartkamp, Remco; Sathian, Sarith P

2018-05-25

We investigate thermally driven water droplet transport on graphene and hexagonal boron nitride (h-BN) surfaces using molecular dynamics simulations. The two surfaces considered here have different wettabilities with a significant difference in the mode of droplet transport. The water droplet travels along a straighter path on the h-BN sheet than on graphene. The h-BN surface produced a higher driving force on the droplet than the graphene surface. The water droplet is found to move faster on h-BN surface compared to graphene surface. The instantaneous contact angle was monitored as a measure of droplet deformation during thermal transport. The characteristics of the droplet motion on both surfaces is determined through the moment scaling spectrum. The water droplet on h-BN surface showed the attributes of the super-diffusive process, whereas it was sub-diffusive on the graphene surface.

Thermophoretically driven water droplets on graphene and boron nitride surfaces

NASA Astrophysics Data System (ADS)

Rajegowda, Rakesh; Kannam, Sridhar Kumar; Hartkamp, Remco; Sathian, Sarith P.

2018-05-01

We investigate thermally driven water droplet transport on graphene and hexagonal boron nitride (h-BN) surfaces using molecular dynamics simulations. The two surfaces considered here have different wettabilities with a significant difference in the mode of droplet transport. The water droplet travels along a straighter path on the h-BN sheet than on graphene. The h-BN surface produced a higher driving force on the droplet than the graphene surface. The water droplet is found to move faster on h-BN surface compared to graphene surface. The instantaneous contact angle was monitored as a measure of droplet deformation during thermal transport. The characteristics of the droplet motion on both surfaces is determined through the moment scaling spectrum. The water droplet on h-BN surface showed the attributes of the super-diffusive process, whereas it was sub-diffusive on the graphene surface.

Rates of Dinitrogen Fixation and the Abundance of Diazotrophs in North American Coastal Waters Between Cape Hatteras and Georges Bank

NASA Technical Reports Server (NTRS)

Mulholland, M.R.; Bernhardt, P. W.; Blanco-Garcia, J. L.; Mannino, A.; Hyde, K.; Mondragon, E.; Turk, K.; Moisander, P. H.; Zehr, J. P.

2012-01-01

We coupled dinitrogen (N2) fixation rate estimates with molecular biological methods to determine the activity and abundance of diazotrophs in coastal waters along the temperate North American Mid-Atlantic continental shelf during multiple seasons and cruises. Volumetric rates of N2 fixation were as high as 49.8 nmol N L(sup -1) d(sup -1) and areal rates as high as 837.9 micromol N m(sup -2) d(sup -1) in our study area. Our results suggest that N2 fixation occurs at high rates in coastal shelf waters that were previously thought to be unimportant sites of N2 fixation and so were excluded from calculations of pelagic marine N2 fixation. Unicellular N2-fixing group A cyanobacteria were the most abundant diazotrophs in the Atlantic coastal waters and their abundance was comparable to, or higher than, that measured in oceanic regimes where they were discovered. High rates of N2 fixation and the high abundance of diazotrophs along the North American Mid-Atlantic continental shelf highlight the need to revise marine N budgets to include coastal N2 fixation. Integrating areal rates of N2 fixation over the continental shelf area between Cape Hatteras and Nova Scotia, the estimated N2 fixation in this temperate shelf system is about 0.02 Tmol N yr(sup -1), the amount previously calculated for the entire North Atlantic continental shelf. Additional studies should provide spatially, temporally, and seasonally resolved rate estimates from coastal systems to better constrain N inputs via N2 fixation from the neritic zone.

Spatial and Temporal Variation in Enterococcal Abundance and Its Relationship to the Microbial Community in Hawaii Beach Sand and Water

PubMed Central

Cui, Henglin; Yang, Kun; Pagaling, Eulyn

2013-01-01

Recent studies have reported high levels of fecal indicator enterococci in marine beach sand. This study aimed to determine the spatial and temporal variation of enterococcal abundance and to evaluate its relationships with microbial community parameters in Hawaii beach sand and water. Sampling at 23 beaches on the Island of Oahu detected higher levels of enterococci in beach foreshore sand than in beach water on a mass unit basis. Subsequent 8-week consecutive samplings at two selected beaches (Waialae and Kualoa) consistently detected significantly higher levels of enterococci in backshore sand than in foreshore/nearshore sand and beach water. Comparison between the abundance of enterococci and the microbial communities showed that enterococci correlated significantly with total Vibrio in all beach zones but less significantly with total bacterial density and Escherichia coli. Samples from the different zones of Waialae beach were sequenced by 16S rRNA gene pyrosequencing to determine the microbial community structure and diversity. The backshore sand had a significantly more diverse community and contained different major bacterial populations than the other beach zones, which corresponded to the spatial distribution pattern of enterococcal abundance. Taken together, multiple lines of evidence support the possibility of enterococci as autochthonous members of the microbial community in Hawaii beach sand. PMID:23563940

Surface-water quality-assurance plan for the U.S. Geological Survey Washington Water Science Center

USGS Publications Warehouse

Mastin, Mark C.

2016-02-19

This Surface-Water Quality-Assurance Plan documents the standards, policies, and procedures used by the U.S. Geological Survey Washington Water Science Center (WAWSC) for activities related to the collection, processing, storage, analysis, and publication of surface-water data. This plan serves as a guide to all WAWSC personnel involved in surface-water data activities, and changes as the needs and requirements of the WAWSC change. Regular updates to this plan represent an integral part of the quality-assurance process. In the WAWSC, direct oversight and responsibility by the hydrographer(s) assigned to a surface-water station, combined with team approaches in all work efforts, assure highquality data, analyses, reviews, and reports for cooperating agencies and the public.

Occurrence of Surface Water Contaminations: An Overview

NASA Astrophysics Data System (ADS)

Shahabudin, M. M.; Musa, S.

2018-04-01

Water is a part of our life and needed by all organisms. As time goes by, the needs by human increased transforming water quality into bad conditions. Surface water contaminated in various ways which is pointed sources and non-pointed sources. Pointed sources means the source are distinguished from the source such from drains or factory but the non-pointed always occurred in mixed of elements of pollutants. This paper is reviewing the occurrence of the contaminations with effects that occurred around us. Pollutant factors from natural or anthropology factors such nutrients, pathogens, and chemical elements contributed to contaminations. Most of the effects from contaminated surface water contributed to the public health effects also to the environments.

Polyoxometalate electrocatalysts based on earth-abundant metals for efficient water oxidation in acidic media

NASA Astrophysics Data System (ADS)

Blasco-Ahicart, Marta; Soriano-López, Joaquín; Carbó, Jorge J.; Poblet, Josep M.; Galan-Mascaros, J. R.

2018-01-01

Water splitting is a promising approach to the efficient and cost-effective production of renewable fuels, but water oxidation remains a bottleneck in its technological development because it largely relies on noble-metal catalysts. Although inexpensive transition-metal oxides are competitive water oxidation catalysts in alkaline media, they cannot compete with noble metals in acidic media, in which hydrogen production is easier and faster. Here, we report a water oxidation catalyst based on earth-abundant metals that performs well in acidic conditions. Specifically, we report the enhanced catalytic activity of insoluble salts of polyoxometalates with caesium or barium counter-cations for oxygen evolution. In particular, the barium salt of a cobalt-phosphotungstate polyanion outperforms the state-of-the-art IrO2 catalyst even at pH < 1, with an overpotential of 189 mV at 1 mA cm-2. In addition, we find that a carbon-paste conducting support with a hydrocarbon binder can improve the stability of metal-oxide catalysts in acidic media by providing a hydrophobic environment.

Water resources data for New Mexico, water year 1964; Part I. Surface water records

USGS Publications Warehouse

,

1965-01-01

The surface-water records for the 1964 water year for gaging stations, partialrecord stations, and miscellaneous sites within the State of New Mexico are given in this report. For convenience there are also included records for a few pertinent gaging stations in bordering States. The records were collected and computed by the Water Resources Division of the U. S. Geological Survey, under the direction of W. L. Heckler, district engineer, Surface Water Branch. This report is the fourth in a series presenting, annually, basic data on surfacewater records by States. Through September 30, 1960, the records of discharge and stage of streams and contents and stage of lakes or reservoirs were published in an annual series of U. S. Geological Survey water-supply papers entitled "Surface Water Supply of the United States." Since 1951 there have been 20 volumes in the series; each volume covered an area whose boundaries coincided with those of certain natural drainage areas. The records in New Mexico were contained in Parts 7, 8, and 9 of that series. Beginning with the 1961 water year, streamflow records and related data will be released by the Geological Survey in annual reports on a State-boundary basis. Distribution of these basic-data reports will be limited and primarily for local needs. The records later will be published in Geological Survey water-supply papers at 5-year intervals. These 5-year water-supply papers will show daily discharge and will be compiled on the same geographical areas previously used for the annual series; however, some of the 14 parts of conterminous United States will be further subdivided.

New insights into ocean sunfish (Mola mola) abundance and seasonal distribution in the northeast Atlantic.

PubMed

Breen, Patricia; Cañadas, Ana; Cadhla, Oliver Ó; Mackey, Mick; Scheidat, Meike; Geelhoed, Steve C V; Rogan, Emer; Jessopp, Mark

2017-05-17

The ocean sunfish, Mola mola, is the largest teleost fish in the world. Despite being found in all oceans of the world, little is known about its abundance and factors driving its distribution. In this study we provide the first abundance estimates for sunfish in offshore waters in the northeast Atlantic and the first record of extensive sunfish presence in these waters year-round. Abundance estimates and predictive distributions for sunfish in approximately 300,000 km² of the northeast Atlantic were derived from large scale offshore aerial surveys in 2015-2016 using distance sampling techniques. Generalized additive models of sunfish density were fitted to survey data from 17,360 km of line transect effort resulting in minimum abundance estimates of 12,702 (CI: 9,864-16,357) in the summer (Density = 0.043 ind/km²) and 8,223 individuals (CI: 6,178-10,946) (Density = 0.028 ind/km²) in the winter. Density surface models predicted seasonal shifts in distribution and highlighted the importance of the mixed layer depth, possibly related to thermoregulation following deep foraging dives. The abundance estimate and estimated daily consumption of 2,600 tonnes of jellyfish in the northeast Atlantic highlights the need to re-assess the importance of this species in the pelagic ecosystem, and its role in top-down control of jellyfish blooms.

Impact of Water Recovery from Wastes on the Lunar Surface Mission Water Balance

NASA Technical Reports Server (NTRS)

Fisher, John W.; Hogan, John Andrew; Wignarajah, Kanapathipi; Pace, Gregory S.

2010-01-01

Future extended lunar surface missions will require extensive recovery of resources to reduce mission costs and enable self-sufficiency. Water is of particular importance due to its potential use for human consumption and hygiene, general cleaning, clothes washing, radiation shielding, cooling for extravehicular activity suits, and oxygen and hydrogen production. Various water sources are inherently present or are generated in lunar surface missions, and subject to recovery. They include: initial water stores, water contained in food, human and other solid wastes, wastewaters and associated brines, ISRU water, and scavenging from residual propellant in landers. This paper presents the results of an analysis of the contribution of water recovery from life support wastes on the overall water balance for lunar surface missions. Water in human wastes, metabolic activity and survival needs are well characterized and dependable figures are available. A detailed life support waste model was developed that summarizes the composition of life support wastes and their water content. Waste processing technologies were reviewed for their potential to recover that water. The recoverable water in waste is a significant contribution to the overall water balance. The value of this contribution is discussed in the context of the other major sources and loses of water. Combined with other analyses these results provide guidance for research and technology development and down-selection.

Quality-control results for ground-water and surface-water data, Sacramento River Basin, California, National Water-Quality Assessment, 1996-1998

USGS Publications Warehouse

Munday, Cathy; Domagalski, Joseph L.

2003-01-01

Evaluating the extent that bias and variability affect the interpretation of ground- and surface-water data is necessary to meet the objectives of the National Water-Quality Assessment (NAWQA) Program. Quality-control samples used to evaluate the bias and variability include annual equipment blanks, field blanks, field matrix spikes, surrogates, and replicates. This report contains quality-control results for the constituents critical to the ground- and surface-water components of the Sacramento River Basin study unit of the NAWQA Program. A critical constituent is one that was detected frequently (more than 50 percent of the time in blank samples), was detected at amounts exceeding water-quality standards or goals, or was important for the interpretation of water-quality data. Quality-control samples were collected along with ground- and surface-water samples during the high intensity phase (cycle 1) of the Sacramento River Basin NAWQA beginning early in 1996 and ending in 1998. Ground-water field blanks indicated contamination of varying levels of significance when compared with concentrations detected in environmental ground-water samples for ammonia, dissolved organic carbon, aluminum, and copper. Concentrations of aluminum in surface-water field blanks were significant when compared with environmental samples. Field blank samples collected for pesticide and volatile organic compound analyses revealed no contamination in either ground- or surface-water samples that would effect the interpretation of environmental data, with the possible exception of the volatile organic compound trichloromethane (chloroform) in ground water. Replicate samples for ground water and surface water indicate that variability resulting from sample collection, processing, and analysis was generally low. Some of the larger maximum relative percentage differences calculated for replicate samples occurred between samples having lowest absolute concentration differences and(or) values near

Wind and sunlight shape microbial diversity in surface waters of the North Pacific Subtropical Gyre

PubMed Central

Bryant, Jessica A; Aylward, Frank O; Eppley, John M; Karl, David M; Church, Matthew J; DeLong, Edward F

2016-01-01

Few microbial time-series studies have been conducted in open ocean habitats having low seasonal variability such as the North Pacific Subtropical Gyre (NPSG), where surface waters experience comparatively mild seasonal variation. To better describe microbial seasonal variability in this habitat, we analyzed rRNA amplicon and shotgun metagenomic data over two years at the Hawaii Ocean Time-series Station ALOHA. We postulated that this relatively stable habitat might reveal different environmental factors that influence planktonic microbial community diversity than those previously observed in more seasonally dynamic habitats. Unexpectedly, the data showed that microbial diversity at 25 m was positively correlated with average wind speed 3 to 10 days prior to sampling. In addition, microbial community composition at 25 m exhibited significant correlations with solar irradiance. Many bacterial groups whose relative abundances varied with solar radiation corresponded to taxa known to exhibit strong seasonality in other oceanic regions. Network co-correlation analysis of 25 m communities showed seasonal transitions in composition, and distinct successional cohorts of co-occurring phylogenetic groups. Similar network analyses of metagenomic data also indicated distinct seasonality in genes originating from cyanophage, and several bacterial clades including SAR116 and SAR324. At 500 m, microbial community diversity and composition did not vary significantly with any measured environmental parameters. The minimal seasonal variability in the NPSG facilitated detection of more subtle environmental influences, such as episodic wind variation, on surface water microbial diversity. Community composition in NPSG surface waters varied in response to solar irradiance, but less dramatically than reported in other ocean provinces. PMID:26645474

Wind and sunlight shape microbial diversity in surface waters of the North Pacific Subtropical Gyre.

PubMed

Bryant, Jessica A; Aylward, Frank O; Eppley, John M; Karl, David M; Church, Matthew J; DeLong, Edward F

2016-06-01

Few microbial time-series studies have been conducted in open ocean habitats having low seasonal variability such as the North Pacific Subtropical Gyre (NPSG), where surface waters experience comparatively mild seasonal variation. To better describe microbial seasonal variability in this habitat, we analyzed rRNA amplicon and shotgun metagenomic data over two years at the Hawaii Ocean Time-series Station ALOHA. We postulated that this relatively stable habitat might reveal different environmental factors that influence planktonic microbial community diversity than those previously observed in more seasonally dynamic habitats. Unexpectedly, the data showed that microbial diversity at 25 m was positively correlated with average wind speed 3 to 10 days prior to sampling. In addition, microbial community composition at 25 m exhibited significant correlations with solar irradiance. Many bacterial groups whose relative abundances varied with solar radiation corresponded to taxa known to exhibit strong seasonality in other oceanic regions. Network co-correlation analysis of 25 m communities showed seasonal transitions in composition, and distinct successional cohorts of co-occurring phylogenetic groups. Similar network analyses of metagenomic data also indicated distinct seasonality in genes originating from cyanophage, and several bacterial clades including SAR116 and SAR324. At 500 m, microbial community diversity and composition did not vary significantly with any measured environmental parameters. The minimal seasonal variability in the NPSG facilitated detection of more subtle environmental influences, such as episodic wind variation, on surface water microbial diversity. Community composition in NPSG surface waters varied in response to solar irradiance, but less dramatically than reported in other ocean provinces.

Spatial and temporal variability in coccolithophore abundance and distribution in the NW Iberian coastal upwelling system

NASA Astrophysics Data System (ADS)

Ausín, Blanca; Zúñiga, Diana; Flores, Jose A.; Cavaleiro, Catarina; Froján, María; Villacieros-Robineau, Nicolás; Alonso-Pérez, Fernando; Arbones, Belén; Santos, Celia; de la Granda, Francisco; Castro, Carmen G.; Abrantes, Fátima; Eglinton, Timothy I.; Salgueiro, Emilia

2018-01-01

A systematic investigation of the spatial and temporal variability in coccolithophore abundance and distribution through the water column of the NW Iberian coastal upwelling system was performed. From July 2011 to June 2012, monthly sampling at various water depths was conducted at two parallel stations located at 42° N. Total coccosphere abundance was higher at the outer-shelf station, where warmer, nutrient-depleted waters favoured coccolithophore rather than phytoplanktonic diatom blooms, which are known to dominate the inner-shelf location. In seasonal terms, higher coccosphere and coccolith abundances were registered at both stations during upwelling seasons, coinciding with high irradiance levels. This was typically in conjunction with stratified, nutrient-poor conditions (i.e. relaxing upwelling conditions). However, it also occurred during some upwelling events of colder, nutrient-rich subsurface waters onto the continental shelf. Minimum abundances were generally found during downwelling periods, with unexpectedly high coccolith abundance registered in subsurface waters at the inner-shelf station. This finding can only be explained if strong storms during these downwelling periods favoured resuspension processes, thus remobilizing deposited coccoliths from surface sediments, and hence hampering the identification of autochthonous coccolithophore community structure. At both locations, the major coccolithophore assemblages were dominated by Emiliania huxleyi, small Gephyrocapsa group, Gephyrocapsa oceanica, Florisphaera profunda, Syracosphaera spp., Coronosphaera mediterranea, and Calcidiscus leptoporus. Ecological preferences of the different taxa were assessed by exploring the relationships between environmental conditions and temporal and vertical variability in coccosphere abundance. These findings provide relevant information for the use of fossil coccolith assemblages in marine sediment records, in order to infer past environmental conditions, of

Documentation of the Surface-Water Routing (SWR1) Process for modeling surface-water flow with the U.S. Geological Survey Modular Ground-Water Model (MODFLOW-2005)

USGS Publications Warehouse

Hughes, Joseph D.; Langevin, Christian D.; Chartier, Kevin L.; White, Jeremy T.

2012-01-01

A flexible Surface-Water Routing (SWR1) Process that solves the continuity equation for one-dimensional and two-dimensional surface-water flow routing has been developed for the U.S. Geological Survey three-dimensional groundwater model, MODFLOW-2005. Simple level- and tilted-pool reservoir routing and a diffusive-wave approximation of the Saint-Venant equations have been implemented. Both methods can be implemented in the same model and the solution method can be simplified to represent constant-stage elements that are functionally equivalent to the standard MODFLOW River or Drain Package boundary conditions. A generic approach has been used to represent surface-water features (reaches) and allows implementation of a variety of geometric forms. One-dimensional geometric forms include rectangular, trapezoidal, and irregular cross section reaches to simulate one-dimensional surface-water features, such as canals and streams. Two-dimensional geometric forms include reaches defined using specified stage-volume-area-perimeter (SVAP) tables and reaches covering entire finite-difference grid cells to simulate two-dimensional surface-water features, such as wetlands and lakes. Specified SVAP tables can be used to represent reaches that are smaller than the finite-difference grid cell (for example, isolated lakes), or reaches that cannot be represented accurately using the defined top of the model. Specified lateral flows (which can represent point and distributed flows) and stage-dependent rainfall and evaporation can be applied to each reach. The SWR1 Process can be used with the MODFLOW Unsaturated Zone Flow (UZF1) Package to permit dynamic simulation of runoff from the land surface to specified reaches. Surface-water/groundwater interactions in the SWR1 Process are mathematically defined to be a function of the difference between simulated stages and groundwater levels, and the specific form of the reach conductance equation used in each reach. Conductance can be

Sims Analysis of Water Abundance and Hydrogen Isotope in Lunar Highland Plagioclase

NASA Technical Reports Server (NTRS)

Hui, Hejiu; Guan, Yunbin; Chen, Yang; Peslier, Anne H.; Zhang, Youxue; Liu, Yang; Rossman, George R.; Eiler, John M.; Neal, Clive R.

2015-01-01

The detection of indigenous water in mare basaltic glass beads has challenged the view established since the Apollo era of a "dry" Moon. Since this discovery, measurements of water in lunar apatite, olivine-hosted melt inclusions, agglutinates, and nominally anhydrous minerals have confirmed that lunar igneous materials contain water, implying that some parts of lunar mantle may have as much water as Earth's upper mantle. The interpretation of hydrogen (H) isotopes in lunar samples, however, is controversial. The large variation of H isotope ratios in lunar apatite (delta Deuterium = -202 to +1010 per mille) has been taken as evidence that water in the lunar interior comes from the lunar mantle, solar wind protons, and/or comets. The very low deuterium/H ratios in lunar agglutinates indicate that solar wind protons have contributed to their hydrogen content. Conversely, H isotopes in lunar volcanic glass beads and olivine-hosted melt inclusions being similar to those of common terrestrial igneous rocks, suggest a common origin for water in both Earth and Moon. Lunar water could be inherited from carbonaceous chondrites, consistent with the model of late accretion of chondrite-type materials to the Moon as proposed by. One complication about the sources of lunar water, is that geologic processes (e.g., late accretion and magmatic degassing) may have modified the H isotope signatures of lunar materials. Recent FTIR analyses have shown that plagioclases in lunar ferroan anorthosite contain approximately 6 ppm H2O. So far, ferroan anorthosite is the only available lithology that is believed to be a primary product of the lunar magma ocean (LMO). A possible consequence is that the LMO could have contained up to approximately 320 ppm H2O. Here we examine the possible sources of water in the LMO through measurements of water abundances and H isotopes in plagioclase of two ferroan anorthosites and one troctolite from lunar highlands.

Water transport mechanism through open capillaries analyzed by direct surface modifications on biological surfaces

NASA Astrophysics Data System (ADS)

Ishii, Daisuke; Horiguchi, Hiroko; Hirai, Yuji; Yabu, Hiroshi; Matsuo, Yasutaka; Ijiro, Kuniharu; Tsujii, Kaoru; Shimozawa, Tateo; Hariyama, Takahiko; Shimomura, Masatsugu

2013-10-01

Some small animals only use water transport mechanisms passively driven by surface energies. However, little is known about passive water transport mechanisms because it is difficult to measure the wettability of microstructures in small areas and determine the chemistry of biological surfaces. Herein, we developed to directly analyse the structural effects of wettability of chemically modified biological surfaces by using a nanoliter volume water droplet and a hi-speed video system. The wharf roach Ligia exotica transports water only by using open capillaries in its legs containing hair- and paddle-like microstructures. The structural effects of legs chemically modified with a self-assembled monolayer were analysed, so that the wharf roach has a smart water transport system passively driven by differences of wettability between the microstructures. We anticipate that this passive water transport mechanism may inspire novel biomimetic fluid manipulations with or without a gravitational field.

Modelling surface-water depression storage in a Prairie Pothole Region

USGS Publications Warehouse

Hay, Lauren E.; Norton, Parker A.; Viger, Roland; Markstrom, Steven; Regan, R. Steven; Vanderhoof, Melanie

2018-01-01

In this study, the Precipitation-Runoff Modelling System (PRMS) was used to simulate changes in surface-water depression storage in the 1,126-km2 Upper Pipestem Creek basin located within the Prairie Pothole Region of North Dakota, USA. The Prairie Pothole Region is characterized by millions of small water bodies (or surface-water depressions) that provide numerous ecosystem services and are considered an important contribution to the hydrologic cycle. The Upper Pipestem PRMS model was extracted from the U.S. Geological Survey's (USGS) National Hydrologic Model (NHM), developed to support consistent hydrologic modelling across the conterminous United States. The Geospatial Fabric database, created for the USGS NHM, contains hydrologic model parameter values derived from datasets that characterize the physical features of the entire conterminous United States for 109,951 hydrologic response units. Each hydrologic response unit in the Geospatial Fabric was parameterized using aggregated surface-water depression area derived from the National Hydrography Dataset Plus, an integrated suite of application-ready geospatial datasets. This paper presents a calibration strategy for the Upper Pipestem PRMS model that uses normalized lake elevation measurements to calibrate the parameters influencing simulated fractional surface-water depression storage. Results indicate that inclusion of measurements that give an indication of the change in surface-water depression storage in the calibration procedure resulted in accurate changes in surface-water depression storage in the water balance. Regionalized parameterization of the USGS NHM will require a proxy for change in surface-storage to accurately parameterize surface-water depression storage within the USGS NHM.

Electrodialysis and nanofiltration of surface water for subsequent use as infiltration water.

PubMed

Van der Bruggen, B; Milis, R; Vandecasteele, C; Bielen, P; Van San, E; Huysman, K

2003-09-01

In order to achieve stable groundwater levels, an equilibrium between the use of groundwater for drinking water production and natural or artificial groundwater recharge by infiltration is needed. Local governments usually require that the composition of the water used for artificial recharge is similar to the surface water that is naturally present in the specific recharge area. In this paper, electrodialysis (ED) and nanofiltration were evaluated as possible treatment technologies for surface water from a canal in Flanders, the North of Belgium, in view of infiltration at critical places on heathlands. Both methods were evaluated on the basis of a comparison between the water composition after treatment and the composition of local surface waters. The treatment generally consists of a tuning of pH and the removal of contaminants originating from industrial and agricultural activity, e.g., nitrates and pesticides. Further evaluation of the influence of the composition of the water on the characteristics of the artificial recharge, however, was not envisaged. In a case study of water from the canal Schoten-Dessel, satisfactory concentration reductions of Cl(-), SO(4)(2-), NO(3)(-), HCO(3)(-), Na(+), Mg(2+), K(+) and Ca(2+) were obtained by ultrafiltration pretreatment followed by ED. Nanofiltration with UTC-20, N30F, Desal 51 HL, UTC-60 and Desal 5 DL membranes resulted in an insufficient removal level, especially for the monovalent ions.

Modeling Water Redistribution in a Near-Surface Arid Soil

NASA Astrophysics Data System (ADS)

Luo, Y.; Ghezzehei, T. A.; Berli, M.; Dijkema, J.; Koonce, J.

2017-12-01

Desert soils cover about one third of the Earth's land surface and play an important role in the ecology and hydrology of arid environments. Despite their large extend, relatively little is known about their near-surface (top centimeters to meter) water dynamics. Recent studies by Koonce (2016) and Dijkema et al. (2017) shed light on the water dynamics of near-surface arid soil but also revealed some of the challenges to simulate the water redistribution in arid soils. The goal of this study was to improve water redistribution simulations in near-surface arid soils by employing more advanced hydraulic conductivity functions. Expanding on the work by Dijkema et al. (2017), we used a HYDRUS-1D model with different hydraulic conductivity functions to simulate water redistribution within the soil as a function of precipitation, evaporation and drainage. Model calculations were compared with measured data from the SEPHAS weighing lysimeters in Boulder City, NV. Preliminary results indicate that water redistribution simulations of near-surface arid soils can be improved by using hydraulic conductivity functions that can capture capillary, film and vapor flow, like for example the Peter-Durner-Iden (PDI) model.

Coastal surface water suitability analysis for irrigation in Bangladesh

NASA Astrophysics Data System (ADS)

Mahtab, Mohammad Hossain; Zahid, Anwar

2018-03-01

Water with adequate quality and quantity is very important for irrigation to ensure the crop yields. Salinity is common problem in the coastal waters in Bangladesh. The intensity of salinity in the coastal zone in Bangladesh is not same. It fluctuates over the year. Sodium is another hazard which may hamper permeability and ultimately affects the fertility. It can reduce the crop yields. Although surface water is available in the coastal zone of Bangladesh, but its quality for irrigation needs to be monitored over the year. This paper will investigate the overall quality of coastal surface waters. Thirty-three water samples from different rivers were collected both in wet period (October-December) and in dry period (February-April). Different physical and chemical parameters are considered for investigation of the adequacy of water with respect to international irrigation water quality standards and Bangladesh standards. A comparison between the dry and wet period coastal surface water quality in Bangladesh will also be drawn here. The analysis shows that coastal surface water in Bangladesh is overall suitable for irrigation during wet period, while it needs treatment (which will increase the irrigation cost) for using for irrigation during dry period. Adaptation to this situation can improve the scenario. An integrated plan should be taken to increase the water storing capacity in the coastal area to harvest water during wet period.

Foulant characteristics comparison in recycling cooling water system makeup by municipal reclaimed water and surface water in power plant.

PubMed

Ping, Xu; Jing, Wang; Yajun, Zhang; Jie, Wang; Shuai, Si

2015-01-01

Due to water shortage, municipal reclaimed water rather than surface water was replenished into recycling cooling water system in power plants in some cities in China. In order to understand the effects of the measure on carbon steel corrosion, characteristics of two kinds of foulant produced in different systems were studied in the paper. Differences between municipal reclaimed water and surface water were analyzed firstly. Then, the weight and the morphology of two kinds of foulant were compared. Moreover, other characteristics including the total number of bacteria, sulfate reducing bacteria, iron bacteria, extracellular polymeric substance (EPS), protein (PN), and polysaccharide (PS) in foulant were analyzed. Based on results, it could be concluded that microbial and corrosive risk would be increased when the system replenished by municipal reclaimed water instead of surface water.

Foulant Characteristics Comparison in Recycling Cooling Water System Makeup by Municipal Reclaimed Water and Surface Water in Power Plant

PubMed Central

Ping, Xu; Jing, Wang; Yajun, Zhang; Jie, Wang; Shuai, Si

2015-01-01

Due to water shortage, municipal reclaimed water rather than surface water was replenished into recycling cooling water system in power plants in some cities in China. In order to understand the effects of the measure on carbon steel corrosion, characteristics of two kinds of foulant produced in different systems were studied in the paper. Differences between municipal reclaimed water and surface water were analyzed firstly. Then, the weight and the morphology of two kinds of foulant were compared. Moreover, other characteristics including the total number of bacteria, sulfate reducing bacteria, iron bacteria, extracellular polymeric substance (EPS), protein (PN), and polysaccharide (PS) in foulant were analyzed. Based on results, it could be concluded that microbial and corrosive risk would be increased when the system replenished by municipal reclaimed water instead of surface water. PMID:25893132

Water resources data for Michigan, water year 1972; Part 1, Surface water records

USGS Publications Warehouse

,

1973-01-01

Surface-water records for the 1972 water year for gaging stations, partial-record stations, and miscellaneous sites within the State of Michigan are given in this report. For convenience there are also included records for a few pertinent gaging stations in bordering States. The records were collected and computed by the Water Resources Division of the U.S. Geological Survey, under the direction of T. R. Cummings, district chief. These data represent that portion of the National Water Data System collected by the U.S. Geological Survey and cooperating State and Federal agencies in Michigan. Records of discharge and stage of streams, and contents and stage of lakes or reservoirs are published in a series of U.S. Geological Survey water-supply papers entitled "Surface Water Supply of the United States". Through September 30, 1960, these water-supply papers were in an annual series and since then are in a 5-year series. Since 1951 there have been 20 volumes in the series; each volume covered an area whose boundaries coincided with those of certain natural drainage areas. The records in Michigan were contained in Part 4 of that series. Beginning with the 1961 water year, streamflow records and related data have been released by the Geological Survey in annual reports on a State-boundary basis. Distribution of these basic-data reports is limited and primarily for local needs.

Water resources data for Michigan, water year 1971; Part 1, Surface water records

USGS Publications Warehouse

,

1972-01-01

Surface-water records for the 1971 water year for gaging stations, partial-record stations, and miscellaneous sites within the State of Michigan are given in this report. For convenience there are also included records for a few pertinent gaging stations in bordering States. The records were collected and computed by the Water Resources Division of the U.S. Geological Survey, under the direction of T. R. Cummings, district chief. These data represent that portion of the National Water Data System collected by the U.S. Geological Survey and cooperating State and Federal agencies in Michigan. Records of discharge and stage of streams, and contents and stage of lakes or reservoirs are published in a series of U.S. Geological Survey water-supply papers entitled "Surface Water Supply of the United States." Through September 30, 1960, these water-supply papers were in an annual series and since then are in a 5-year series. Since 1951 there have been 20 volumes in the series; each volume covered an area whose boundaries coincided with those of certain natural drainage areas. The records in Michigan were contained in Part 4 of that series. Beginning with the 1961 water year, streamflow records and related data have been released by the Geological Survey in annual reports on a State-boundary basis. Distribution of these basic-data reports is limited and primarily for local needs.

Water resources data for Michigan, water year 1973; Part 1, Surface water records

USGS Publications Warehouse

,

1974-01-01

Surface-water records for the 1973 water year for gaging stations, partial-record stations, and miscellaneous sites within the State of Michigan are given in this report. For convenience there are also included records for a few pertinent gaging stations in bordering States. The records were collected and computed by the Water Resources Division of the U.S. Geological Survey, under the direction of T.R. Cummings, district chief. These data represent that portion of the National Water Data System collected by the U.S. Geological Survey and cooperating State and Federal agencies in Michigan. Records of discharge and stage of streams, and contents and stage of lakes or reservoirs are published in a series of U.S. Geological Survey water-supply papers entitled "Surface Water Supply of the United States". Through September 30, 1960, these water-supply papers were in an annual series and since then are in a 5-year series. Since 1951 there have been 20 volumes in the series; each volume covered an area whose boundaries coincided with those of certain natural drainage areas. The records in Michigan are contained in Part 4 of that series. Beginning with the 1961 water year, streamflow records and related data have been released by the Geological Survey in annual reports on a State-boundary basis. Distribution of these basic-data reports is limited and primarily for local needs.

How well Can We Classify SWOT-derived Water Surface Profiles?

NASA Astrophysics Data System (ADS)

Frasson, R. P. M.; Wei, R.; Picamilh, C.; Durand, M. T.

2015-12-01

The upcoming Surface Water Ocean Topography (SWOT) mission will detect water bodies and measure water surface elevation throughout the globe. Within its continental high resolution mask, SWOT is expected to deliver measurements of river width, water elevation and slope of rivers wider than ~50 m. The definition of river reaches is an integral step of the computation of discharge based on SWOT's observables. As poorly defined reaches can negatively affect the accuracy of discharge estimations, we seek strategies to break up rivers into physically meaningful sections. In the present work, we investigate how accurately we can classify water surface profiles based on simulated SWOT observations. We assume that most river sections can be classified as either M1 (mild slope, with depth larger than the normal depth), or A1 (adverse slope with depth larger than the critical depth). This assumption allows the classification to be based solely on the second derivative of water surface profiles, with convex profiles being classified as A1 and concave profiles as M1. We consider a HEC-RAS model of the Sacramento River as a representation of the true state of the river. We employ the SWOT instrument simulator to generate a synthetic pass of the river, which includes our best estimates of height measurement noise and geolocation errors. We process the resulting point cloud of water surface heights with the RiverObs package, which delineates the river center line and draws the water surface profile. Next, we identify inflection points in the water surface profile and classify the sections between the inflection points. Finally, we compare our limited classification of simulated SWOT-derived water surface profile to the "exact" classification of the modeled Sacramento River. With this exercise, we expect to determine if SWOT observations can be used to find inflection points in water surface profiles, which would bring knowledge of flow regimes into the definition of river reaches.

Surface abundance and the hunt for stratification in chemically peculiar hot subdwarfs: PG 0909+276 and UVO 0512-08

NASA Astrophysics Data System (ADS)

Wild, J. F.; Jeffery, C. S.

2018-01-01

Edelmann identified two chemically peculiar hot subdwarfs, PG 0909+276 and UVO 0512-08, as having very high overabundances of iron-group elements. We obtained high-resolution ultraviolet spectroscopy in order to measure abundances of species not observable in the optical, and to seek evidence for chemical stratification in the photosphere. Abundances were measured in three wavelength regions; the optical 3900-6900 Å range was re-analysed to confirm consistency with that analysed by Edelmann. Ultraviolet spectra were obtained with the Space Telescope Imaging Spectrograph on the Hubble Space Telescope, covering the far-UV (1140-1740 Å) and the near-UV (1740-2500 Å). We computed a grid of theoretical local thermodynamic equilibrium spectra to find basic parameters (effective temperatures, surface gravity, surface hydrogen and helium fractions). We measured abundances using a spectral-synthesis approach in each wavelength range. We confirm that several iron-group metals are highly enriched, including cobalt, copper and zinc, relative to typical sdB stars. We detect gallium, germanium, tin and lead, similar to analysis of ultraviolet spectra of some other sdB stars. Our results confirm that PG 0909+276 and UVO 0512-08 exhibit peculiarities which make them distinct from both the normal H-rich sdB and intermediate He-rich sdB stars. The process which leads to this particular composition has still to be identified.

Effective use of surface-water management to control saltwater intrusion

NASA Astrophysics Data System (ADS)

Hughes, J. D.; White, J.

2012-12-01

The Biscayne aquifer in southeast Florida is susceptible to saltwater intrusion and inundation from rising sea-level as a result of high groundwater withdrawal rates and low topographic relief. Groundwater levels in the Biscayne aquifer are managed by an extensive canal system that is designed to control flooding, supply recharge to municipal well fields, and control saltwater intrusion. We present results from an integrated surface-water/groundwater model of a portion of the Biscayne aquifer to evaluate the ability of the existing managed surface-water control network to control saltwater intrusion. Surface-water stage and flow are simulated using a hydrodynamic model that solves the diffusive-wave approximation of the depth-integrated shallow surface-water equations. Variable-density groundwater flow and fluid density are solved using the Oberbeck--Boussinesq approximation of the three-dimensional variable-density groundwater flow equation and a sharp interface approximation, respectively. The surface-water and variable-density groundwater domains are implicitly coupled during each Picard iteration. The Biscayne aquifer is discretized into a multi-layer model having a 500-m square horizontal grid spacing. All primary and secondary surface-water features in the active model domain are discretized into segments using the 500-m square horizontal grid. A 15-year period of time is simulated and the model includes 66 operable surface-water control structures, 127 municipal production wells, and spatially-distributed daily internal and external hydrologic stresses. Numerical results indicate that the existing surface-water system can be effectively used in many locations to control saltwater intrusion in the Biscayne aquifer resulting from increases in groundwater withdrawals or sea-level rise expected to occur over the next 25 years. In other locations, numerical results indicate surface-water control structures and/or operations may need to be modified to control

Summary of hydrogeology and simulation of ground-water flow and land-surface subsidence in the northern part of the Gulf Coast aquifer system, Texas

USGS Publications Warehouse

Kasmarek, Mark C.; Robinson, James L.

2004-01-01

The northern part of the Gulf Coast aquifer system in Texas, which includes the Chicot, Evangeline, and Jasper aquifers, supplies most of the water used for industrial, municipal, agricultural, and commercial purposes for an approximately 25,000- square-mile (mi2) area that includes the Beaumont and Houston metropolitan areas. The area has an abundant amount of potable ground water, but withdrawals of large quantities of ground water have resulted in potentiometric-surface declines in the Chicot, Evangeline, and Jasper aquifers and land-surface subsidence from depressurization and compaction of clay layers interbedded in the aquifer sediments. This fact sheet summarizes a study done in cooperation with the Texas Water Development Board (TWDB) and the Harris-Galveston Coastal Subsidence District (HGCSD) as a part of the TWDB Ground-Water Availability Modeling (or Model) (GAM) program. The study was designed to develop and test a ground-water-flow model of the northern part of the Gulf Coast aquifer system in the GAM area (fig. 1) that waterresource managers can use as a tool to address future groundwater- availability issues.

Water Resources Data: New Jersey, Water Year 1998, Volume 1, Surface-Water Data

USGS Publications Warehouse

Reed, T.J.; Centinaro, G.L.; Dudek, J.F.; Corcino, V.; Stekroadt, G.C.; McTigure, R.C.

1999-01-01

This volume of the annual hydrologic data report of New Jersey is one of a series of annual reports that document hydrologic data gathered from the U.S. Geological Survey's surface- and ground-water data-collection networks in each State, Puerto Rico, and the Trust Territories. These records of streamflow, ground-water levels, and water quality provide the hydrologic information needed by state, local and federal agencies, and the private sector for developing and managing our Nation's land and water resources.

Calcareous Nannoplankton Response to Surface-Water Acidification Around Oceanic Anoxic Event 1a

NASA Astrophysics Data System (ADS)

Erba, Elisabetta; Bottini, Cinzia; Weissert, Helmut J.; Keller, Christina E.

2010-07-01

Ocean acidification induced by atmospheric CO2 may be a major threat to marine ecosystems, particularly to calcareous nannoplankton. We show that, during the Aptian (~120 million years ago) Oceanic Anoxic Event 1a, which resulted from a massive addition of volcanic CO2, the morphological features of calcareous nannofossils traced the biological response to acidified surface waters. We observe the demise of heavily calcified nannoconids and reduced calcite paleofluxes at the beginning of a pre-anoxia calcification crisis. Ephemeral coccolith dwarfism and malformation represent species-specific adjustments to survive lower pH, whereas later, abundance peaks indicate intermittent alkalinity recovery. Deepwater acidification occurred with a delay of 25,000 to 30,000 years. After the dissolution climax, nannoplankton and carbonate recovery developed over ~160,000 years under persisting global dysoxia-anoxia.

Seasonal and intraseasonal variations in evaporation and surface energy budget from eddy covariance measurements over an open water surface in Mississippi, U.S.A.

NASA Astrophysics Data System (ADS)

Liu, H.; Zhang, Y.; Williams, Q. L.; Jiang, H.; Sheng, L.

2008-12-01

Understanding seasonal and intraseasonal variations in evaporation over lake/reservoir is important for water resource management as well as predicting variations in hydrology as a result of climate change. Since August of 2007, we have conducted a long-term eddy covariance measurement of evaporation and the surface energy budget over Ross Barnett Reservoir (32o26'N, 90o02'W) in Mississippi, USA. The fetch for eddy covariance system exceeds 2 km in all directions and the water depth is about 4 m around the flux tower. The tower with its height of 4 m stands over a stationary wood platform with its size of 3 m × 3 m and height of about 1 m above the water surface. Along with sensible and latent heat fluxes, microclimate data are also measured, including wind speed, wind direction, relative humidity, solar radiation, net radiation, air temperature at four levels, water surface temperature, and water temperature at eight depths down to about 4 m. Mississippi is subject to frequent influences of different synoptic weather systems in a year around. Incursions of these different systems bring in air masses with different properties in temperature and moisture. Cold fronts, for example, carry them with cold and dry air from north while warm fronts with warm and moist air. Our results indicate that synoptic weather variations play an important role in controlling evaporations and the surface energy budget. For example, daily H and LE (i.e., evaporation) during the passages of cold fronts are around 2-4 times those of normal days and these cold front events lead to an increase in the seasonal H by approximately 420 and LE by 160%. However, the warm weather systems suppress largely the turbulent exchanges of sensible and latent heat, leading to very small evaporation and sensible heat fluxes (even negative). These results imply that future potential changes in cold front activities (intensity, frequency, and duration) as a result of climate change may lead to substantial

Water Adsorption on Clean and Defective Anatase TiO2 (001) Nanotube Surfaces: A Surface Science Approach.

PubMed

Kenmoe, Stephane; Lisovski, Oleg; Piskunov, Sergei; Bocharov, Dmitry; Zhukovskii, Yuri F; Spohr, Eckhard

2018-05-31

We use ab initio molecular dynamics simulations to study the adsorption of thin water films with 1 and 2 ML coverage on anatase TiO 2 (001) nanotubes. The nanotubes are modeled as 2D slabs, which consist of partially constrained and partially relaxed structural motifs from nanotubes. The effect of anion doping on the adsorption is investigated by substituting O atoms with N and S impurities on the nanotube slab surface. Due to strain-induced curvature effects, water adsorbs molecularly on defect-free surfaces via weak bonds on Ti sites and H bonds to surface oxygens. While the introduction of an S atom weakens the interaction of the surface with water, which adsorbs molecularly, the presence of an N impurity renders the surface more reactive to water, with a proton transfer from the water film and the formation of an NH group at the N site. At 2 ML coverage, a further surface-assisted proton transfer takes place in the water film, resulting in the formation of an OH - group and an NH 2 + cationic site on the surface.

Water resources data for Michigan, water year 1974; Part 1, Surface water records

USGS Publications Warehouse

,

1975-01-01

Surface-water records for the 1974 water year for gaging stations, partial-record stations, and miscellaneous sites within the State of Michigan are given in this report. For convenience there are also included records for a few pertinent gaging stations in bordering States. The records were collected and computed by the Water Resources Division of the U.S. Geological Survey, under the direction of T.R. Cummings, district chief. These data represent that portion of the National Water Data System collected by the U.S. Geological Survey and cooperating State and Federal agencies in Michigan.Records of discharge and stage of streams, and contents and stage of lakes or reservoirs are published in a series of U.S. Geological Survey water-supply papers entitled "Surface Water Supply of the United States". Through September 30, 1960, these water-supply papers were in an annual series and since then are in a 5-year series. Since 1951 there have been 20 volumes in the series; each volume covered an area whose boundaries coincided with those of certain natural drainage areas. The records in Michigan are contained in Part 4 of that series.Beginning with the 1961 water year, streamflow records and related data have been released by the Geological Survey in annual reports on a State-boundary basis. Distribution of these basic-data reports is limited and they are designed primarily for rapid release of data shortly after the end of the water year.

Experimental Observation of Dark Solitons on Water Surface

DTIC Science & Technology

2016-06-13

Experimental observation of dark solitons on water surface A. Chabchoub1,∗, O. Kimmoun2, H. Branger3, N. Hoffmann1, D. Proment4, M. Onorato4,5, and N...The shape and width of the soliton depend on the water depth, carrier frequency and the amplitude of the background wave. The experimental data...partic- ular, the governing equation describing the dynamics of weakly nonlinear and quasi -monochromatic waves prop- agating on the surface of water with

Pesticide mitigation strategies for surface water quality

USDA-ARS?s Scientific Manuscript database

Pesticide residues are being increasingly detected in surface water in agricultural and urban areas. In some cases water bodies are being listed under the Clean Water Act 303(d) as impaired and Total Maximum Daily Loads are required to address the impairments in agricultural areas. Pesticides in sur...

Relating the Chemical Composition of Dissolved Organic Matter Draining Permafrost Soils to its Photochemical Degradation in Arctic Surface Waters.

NASA Astrophysics Data System (ADS)

Ward, C.; Cory, R. M.

2015-12-01

Thawing permafrost soils are expected to shift the chemical composition of DOM exported to and degraded in arctic surface waters. While DOM photo-degradation is an important component of the freshwater C cycle in the Arctic, the molecular controls on DOM photo-degradation remain poorly understood, making it difficult to predict how shifting chemical composition may alter DOM photo-degradation in arctic surface waters. To address this knowledge gap, we quantified the susceptibility of DOM draining the shallow organic mat and the deeper permafrost layer to complete photo-oxidation to CO₂ and partial photo-oxidation to compounds that remain in the DOM pool, and investigated changes in DOM chemical composition following sunlight exposure. DOM leached from the organic mat contained higher molecular weight, more oxidized and unsaturated aromatic species compared to permafrost DOM. Despite significant differences in initial chemical composition, permafrost and organic mat DOM had similar susceptibilities to complete photo-oxidation to CO₂. Concurrent losses of carboxyl moieties and shifts in chemical composition during photo-degradation indicated that carboxyl-rich tannin-like compounds in both DOM sources were likely photo-decarboxylated to CO₂. Permafrost DOM had a higher susceptibility to partial photo-oxidation compared to organic mat DOM, potentially due to a lower abundance of phenolic compounds that act as "antioxidants" and slow the oxidation of DOM. These results demonstrated how chemical composition controls the photo-degradation of DOM in arctic surface waters, and that DOM photo-degradation will likely remain an important component of the freshwater C budget in the Arctic with increased export of permafrost DOM to surface waters.

The impacts of land use change on malaria vector abundance in a water-limited, highland region of Ethiopia.

PubMed

Stryker, Jody J; Bomblies, Arne

2012-12-01

Changes in land use and climate are expected to alter the risk of malaria transmission in areas where rainfall limits vector abundance. We use a coupled hydrology-entomology model to investigate the effects of land use change on hydrological processes impacting mosquito abundance in a highland village of Ethiopia. Land use affects partitioning of rainfall into infiltration and runoff that reaches small-scale topographic depressions, which constitute the primary breeding habitat of Anopheles arabiensis mosquitoes. A physically based hydrology model isolates hydrological mechanisms by which land use impacts pool formation and persistence, and an agent-based entomology model evaluates the response of mosquito populations. This approach reproduced observed interannual variability in mosquito abundance between the 2009 and 2010 wet seasons. Several scenarios of land cover were then evaluated using the calibrated, field-validated model. Model results show variation in pool persistence and depth, as well as in mosquito abundance, due to land use changes alone. The model showed particular sensitivity to surface roughness, but also to root zone uptake. Scenarios in which land use was modified from agriculture to forest generally resulted in lowest mosquito abundance predictions; classification of the entire domain as rainforest produced a 34% decrease in abundance compared to 2010 results. This study also showed that in addition to vegetation type, spatial proximity of land use change to habitat locations has an impact on mosquito abundance. This modeling approach can be applied to assess impacts of climate and land use conditions that fall outside of the range of previously observed variability.

The Impacts of Land Use Change on Malaria Vector Abundance in a Water-Limited Highland Region of Ethiopia

NASA Astrophysics Data System (ADS)

Stryker, J.; Bomblies, A.

2012-12-01

Changes in land use and climate are expected to alter risk of malaria transmission in areas where rainfall limits vector abundance. We use a coupled hydrology-entomology model to investigate the effects of land use change on hydrological processes impacting mosquito abundance in a highland village of Ethiopia. Land use affects partitioning of rainfall into infiltration and runoff that reaches small-scale topographic depressions, which constitute the primary breeding habitat of Anopheles arabiensis mosquitoes. A physically-based hydrology model isolates hydrological mechanisms by which land use impacts pool formation and persistence, and an agent-based entomology model evaluates the response of mosquito populations. This approach reproduced observed interannual variability in mosquito abundance between the 2009 and 2010 wet seasons. Several scenarios of land cover were then evaluated using the calibrated, field-validated model. Model results show variation in pool persistence and depth, as well as in mosquito abundance, due to land use changes alone. The model showed particular sensitivity to surface roughness, but also to root zone uptake. Scenarios in which land use was modified from agriculture to forest generally resulted in lowest mosquito abundance predictions; classification of the entire domain as rainforest produced a 34% decrease in abundance compared to 2010 results. This study also showed that in addition to vegetation type, spatial proximity of land use change to habitat locations has an impact on mosquito abundance. This modeling approach can be applied to assess impacts of climate and land use conditions that fall outside of the range of previously observed variability.

The abundance and distribution of water vapor in the Jovian troposphere as inferred from Voyager IRIS observations

NASA Technical Reports Server (NTRS)

Carlson, Barbara E.; Lacis, Andrew A.; Rossow, William B.

1992-01-01

The Voyager IRIS spectra of the Jovian North Equatorial Belt (NEB) hot spots are reanalyzed using a radiative transfer model which includes the full effects of anisotropic multiple scattering by clouds. The atmospheric model includes the three thermochemically predicted cloud layers, NH3, NH4SH, and H2O. Spectrally dependent cloud extinction is modeled using Mie theory and the refractive indices of NH3 ice, NH4SH ice, water, and H2O ice. The upper tropospheric temperature profile, gas abundances, height-dependent parahydrogen profile, and vertical distribution of NH3 cloud opacity are retrieved from an analysis of the far-infrared (180-1200/cm) IRIS observations. With these properties constrained, the 5-micron (1800-2300/cm) observations are analyzed to determine the atmospheric and cloud structure of the deeper atmosphere (P of greater than 1.5 bars). The results show that the abundance of water is at least 1.5 times solar with 2 times solar (0.00276 mixing ratio relative to H2) providing the best-fit to the Voyager IRIS hot spot observations.

Numerical simulation of hydrodynamic processes beneath a wind-driven water surface

NASA Astrophysics Data System (ADS)

Tsai, Wu-ting

Turbulent flow driven by a constant wind stress acting at the water surface was simulated numerically to gain a better understanding of the hydrodynamic processes governing the transfer of slightly soluble gases across the atmosphere-water interfaces. Simulation results show that two distinct flow features, attributed to subsurface surface renewal eddies, appear at the water surface. The first characteristic feature is surface streaming, which consists of high-speed streaks aligned with the wind stress. Floating Lagrangian particles, which are distributed uniformly at the water surface, merge to the predominantly high-speed streaks and form elongated streets immediately after they are released. The second characteristic surface signatures are localized low-speed spots which emerge randomly at the water surface. A high-speed streak bifurcates and forms a dividing flow when it encounters a low-speed surface spot. These coherent surface flow structures are qualitatively identical to those observed in the experiment of Melville et al. [1998]. The persistence of these surface features also suggests that there must exist organized subsurface vortical structures that undergo autonomous generation cycles maintained by self-sustaining mechanisms. These coherent vortical flows serve as the renewal eddies that pump the submerged fluids toward the water surface and bring down the upper fluids, and therefore enhance the scalar exchange between the atmosphere and the water body.

Reconnaissance of the chemical quality of surface waters of the Neches River basin, Texas

USGS Publications Warehouse

Hughes, Leon S.; Leifeste, Donald K.

1967-01-01

with less than 30 ppm hardness. The chloride concentrations are less than 20 ppm in surface water in the southern half of the basin and usually range from 20 to 100 ppm in the northern half of the basin. Concentrations greater than 100 ppm are found only where pollution is occurring. The Neches River basin has an abundance of surface water, but uneven distribution of runoff makes storage projects necessary to provide dependable water supplies. The principal existing reservoirs, with the exception of Striker Creek Reservoir, contain water of excellent quality. Chemical-quality data for the Striker Creek drainage area indicate that its streams are affected by .the disposal of brines associated with oil production. Sam Rayburn Reservoir began impounding water in 1965. The water impounded should prove of acceptable quality for most uses, but municipal and industrial wastes released into the Angelina River near Lufkin may have a degrading effect on the quality of the water, especially during extended periods of low flows. Water available for storage at the many potential reservoir sites will be of good quality; but, if the proposed salt-water barrier is to impound acceptable water, the disposal of oilfield brine into Pine Island Bayou should be discontinued.

Shallow Alluvial Aquifer Ground Water System and Surface Water/Ground Water Interaction, Boulder Creek, Boulder, Colorado

NASA Astrophysics Data System (ADS)

Babcock, K. P.; Ge, S.; Crifasi, R. R.

2006-12-01

Water chemistry in Boulder Creek, Colorado, shows significant variation as the Creek flows through the City of Boulder [Barber et al., 2006]. This variation is partially due to ground water inputs, which are not quantitatively understood. The purpose of this study is (1) to understand ground water movement in a shallow alluvial aquifer system and (2) to assess surface water/ground water interaction. The study area, encompassing an area of 1 mi2, is located at the Sawhill and Walden Ponds area in Boulder. This area was reclaimed by the City of Boulder and Boulder County after gravel mining operations ceased in the 1970's. Consequently, ground water has filled in the numerous gravel pits allowing riparian vegetation regrowth and replanting. An integrated approach is used to examine the shallow ground water and surface water of the study area through field measurements, water table mapping, graphical data analysis, and numerical modeling. Collected field data suggest that lateral heterogeneity exists throughout the unconsolidated sediment. Alluvial hydraulic conductivities range from 1 to 24 ft/day and flow rates range from 0.01 to 2 ft/day. Preliminary data analysis suggests that ground water movement parallels surface topography and does not noticeably vary with season. Recharge via infiltrating precipitation is dependent on evapotranspiration (ET) demands and is influenced by preferential flow paths. During the growing season when ET demand exceeds precipitation rates, there is little recharge; however recharge occurs during cooler months when ET demand is insignificant. Preliminary data suggest that the Boulder Creek is gaining ground water as it traverses the study area. Stream flow influences the water table for distances up to 400 feet. The influence of stream flow is reflected in the zones relatively low total dissolved solids concentration. A modeling study is being conducted to synthesize aquifer test data, ground water levels, and stream flow data. The

Enthalpic Breakdown of Water Structure on Protein Active-Site Surfaces

PubMed Central

Haider, Kamran; Wickstrom, Lauren; Ramsey, Steven; Gilson, Michael K.; Kurtzman, Tom

2016-01-01

The principles underlying water reorganization around simple non-polar solutes are well understood and provide the framework for classical hydrophobic effect, whereby water molecules structure themselves around solutes so that they maintain favorable energetic contacts with both the solute and with other water molecules. However, for certain solute surface topographies, water molecules, due to their geometry and size, are unable to simultaneously maintain favorable energetic contacts with both the surface and neighboring water molecules. In this study, we analyze the solvation of ligand-binding sites for six structurally diverse proteins using hydration site analysis and measures of local water structure, in order to identify surfaces at which water molecules are unable to structure themselves in a way that maintains favorable enthalpy relative to bulk water. These surfaces are characterized by a high degree of enclosure, weak solute-water interactions, and surface constraints that induce unfavorable pair interactions between neighboring water molecules. Additionally, we find that the solvation of charged side-chains in an active site generally results in favorable enthalpy but can also lead to pair interactions between neighboring water molecules that are significantly unfavorable relative to bulk water. We find that frustrated local structure can occur not only in apolar and weakly polar pockets, where overall enthalpy tends to be unfavorable, but also in charged pockets, where overall water enthalpy tends to be favorable. The characterization of local water structure in these terms may prove useful for evaluating the displacement of water from diverse protein active-site environments. PMID:27169482

Diversity and abundance of nitrate assimilation genes in the northern South china sea.

PubMed

Cai, Haiyuan; Jiao, Nianzhi

2008-11-01

Marine heterotrophic microorganisms that assimilate nitrate play an important role in nitrogen and carbon cycling in the water column. The nasA gene, encoding the nitrate assimilation enzyme, was selected as a functional marker to examine the nitrate assimilation community in the South China Sea (SCS). PCR amplification, restriction fragment length polymorphism (RFLP) screening, and phylogenetic analysis of nasA gene sequences were performed to characterize in situ nitrate assimilatory bacteria. Furthermore, the effects of nutrients and other environmental factors on the genetic heterogeneity of nasA fragments from the SCS were evaluated at the surface in three stations, and at two other depths in one of these stations. The diversity indices and rarefaction curves indicated that the nasA gene was more diverse in offshore waters than in the Pearl River estuary. The phylotype rank abundance curve showed an abundant and unique RFLP pattern in all five libraries, indicating that a high diversity but low abundance of nasA existed in the study areas. Phylogenetic analysis of environmental nasA gene sequences further revealed that the nasA gene fragments came from several common aquatic microbial groups, including the Proteobacteria, Cytophaga-Flavobacteria (CF), and Cyanobacteria. In addition to the direct PCR/sequence analysis of environmental samples, we also cultured a number of nitrate assimilatory bacteria isolated from the field. Comparison of nasA genes from these isolates and from the field samples indicated the existence of horizontal nasA gene transfer. Application of real-time quantitative PCR to these nasA genes revealed a great variation in their abundance at different investigation sites and water depths.

A robust Multi-Band Water Index (MBWI) for automated extraction of surface water from Landsat 8 OLI imagery

NASA Astrophysics Data System (ADS)

Wang, Xiaobiao; Xie, Shunping; Zhang, Xueliang; Chen, Cheng; Guo, Hao; Du, Jinkang; Duan, Zheng

2018-06-01

Surface water is vital resources for terrestrial life, while the rapid development of urbanization results in diverse changes in sizes, amounts, and quality of surface water. To accurately extract surface water from remote sensing imagery is very important for water environment conservations and water resource management. In this study, a new Multi-Band Water Index (MBWI) for Landsat 8 Operational Land Imager (OLI) images is proposed by maximizing the spectral difference between water and non-water surfaces using pure pixels. Based on the MBWI map, the K-means cluster method is applied to automatically extract surface water. The performance of MBWI is validated and compared with six widely used water indices in 29 sites of China. Results show that our proposed MBWI performs best with the highest accuracy in 26 out of the 29 test sites. Compared with other water indices, the MBWI results in lower mean water total errors by a range of 9.31%-25.99%, and higher mean overall accuracies and kappa coefficients by 0.87%-3.73% and 0.06-0.18, respectively. It is also demonstrated for MBWI in terms of robustly discriminating surface water from confused backgrounds that are usually sources of surface water extraction errors, e.g., mountainous shadows and dark built-up areas. In addition, the new index is validated to be able to mitigate the seasonal and daily influences resulting from the variations of the solar condition. MBWI holds the potential to be a useful surface water extraction technology for water resource studies and applications.

[Effects of macro-jellyfish abundance dynamics on fishery resource structure in the Yangtze River estuary and its adjacent waters].