Sample records for surface water snail

  1. Land and water snails

    NSDL National Science Digital Library

    Olivia Worland (Purdue University; Biological Sciences)

    2008-06-03

    Land snails live on the land and water snails make water their habitat. Land snails have shells to protect them and so do water snails. Land snails have two sets of antennae, while water snails only have one set.

  2. The microstructures of biomineralized surfaces: a spectroscopic study on the exoskeletons of fresh water (Apple) snail, Pila globosa

    NASA Astrophysics Data System (ADS)

    Prasuna, C. P. Lakshmi; Narasimhulu, K. V.; Gopal, N. O.; Rao, J. Lakshmana; Rao, T. V. R. K.

    2004-08-01

    In view of the importance in understanding biomineralization processes in different molluskan species, the common fresh water apple snail Pila globosa in Indian origin was taken to explore its mineralized exoskeleton structures. The detailed structural studies of the exoskeletons of P. globosa have been undertaken. The isolated layers present in these shells were studied by electron paramagnetic resonance (EPR), optical absorption, and infrared spectral techniques. The EPR spectra of the organic protein layer periostracum show the characteristic signals corresponding to Fe 3+ ions at g=4.1 and 2.0. The EPR spectra of the ostracum (middle) layer at room temperature gives a complicated spectrum consisting of a number of Mn 2+ signals of at least three sets due to the aragonite nature of the material. The results indicate the presence of the multivalent manganese ions, which undergo the redox mechanisms. The thermal variation of the EPR spectra show marked effect on these samples both in g-values and the basic spectral pattern.

  3. Movements of florida apple snails in relation to water levels and drying events

    USGS Publications Warehouse

    Darby, P.C.; Bennetts, R.E.; Miller, S.J.; Percival, H.F.

    2002-01-01

    Florida apple snails (Pomacea Paludosa) apparently have only a limited tolerance to wetland drying events (although little direct evidence exists), but their populations routinely face dry downs under natural and managed water regimes. In this paper, we address speculation that apple snails respond to decreasing water levels and potential drying events by moving toward refugia that remain inundated. We monitored the movements of apple snails in central Florida, USA during drying events at the Blue Cypress Marsh (BC) and at Lake Kissimmee (LK). We monitored the weekly movements of 47 BC snails and 31 LK snails using radio-telemetry. Snails tended to stop moving when water depths were 10 cm. Snails moved along the greatest positive depth gradient (i.e., towards deeper water) when they encountered water depths between 10 and 20 cm. Snails tended to move toward shallower water in water depths ???50 cm, suggesting that snails were avoiding deep water areas such as canals and sloughs. Of the 11 BC snails originally located in the area that eventually went dry, three (27%) were found in deep water refugia by the end of the study. Only one of the 31 LK snails escaped the drying event by moving to deeper water. Our results indicate that some snails may opportunistically escape drying events through movement. The tendency to move toward deeper water was statistically significant and indicates that this behavioral trait might enhance survival when the spatial extent of a dry down is limited. However, as water level falls below 10 cm, snails stop moving and become stranded. As the spatial extent of a dry down increases, we predict that the number of snails stranded would increase proportionally. Stranded Pomacea paludosa must contend with dry marsh conditions, possibly by aestivation. Little more than anecdotal information has been published on P. paludosa aestivation, but it is a common adaptation among other apple snails (Caenogastropoda: Ampullaridae). ?? 2002, The Society of Wetland Scientists.

  4. Wet Adhesion and Adhesive Locomotion of Snails on Anti-Adhesive Non-Wetting Surfaces

    PubMed Central

    Shirtcliffe, Neil J.; McHale, Glen; Newton, Michael I.

    2012-01-01

    Creating surfaces capable of resisting liquid-mediated adhesion is extremely difficult due to the strong capillary forces that exist between surfaces. Land snails use this to adhere to and traverse across almost any type of solid surface of any orientation (horizontal, vertical or inverted), texture (smooth, rough or granular) or wetting property (hydrophilic or hydrophobic) via a layer of mucus. However, the wetting properties that enable snails to generate strong temporary attachment and the effectiveness of this adhesive locomotion on modern super-slippy superhydrophobic surfaces are unclear. Here we report that snail adhesion overcomes a wide range of these microscale and nanoscale topographically structured non-stick surfaces. For the one surface which we found to be snail resistant, we show that the effect is correlated with the wetting response of the surface to a weak surfactant. Our results elucidate some critical wetting factors for the design of anti-adhesive and bio-adhesion resistant surfaces. PMID:22693563

  5. Wet adhesion and adhesive locomotion of snails on anti-adhesive non-wetting surfaces.

    PubMed

    Shirtcliffe, Neil J; McHale, Glen; Newton, Michael I

    2012-01-01

    Creating surfaces capable of resisting liquid-mediated adhesion is extremely difficult due to the strong capillary forces that exist between surfaces. Land snails use this to adhere to and traverse across almost any type of solid surface of any orientation (horizontal, vertical or inverted), texture (smooth, rough or granular) or wetting property (hydrophilic or hydrophobic) via a layer of mucus. However, the wetting properties that enable snails to generate strong temporary attachment and the effectiveness of this adhesive locomotion on modern super-slippy superhydrophobic surfaces are unclear. Here we report that snail adhesion overcomes a wide range of these microscale and nanoscale topographically structured non-stick surfaces. For the one surface which we found to be snail resistant, we show that the effect is correlated with the wetting response of the surface to a weak surfactant. Our results elucidate some critical wetting factors for the design of anti-adhesive and bio-adhesion resistant surfaces. PMID:22693563

  6. The effect of isolation on reproduction and growth of Pseudosuccinea columella (Pulmonata: Lymnaeidae): a snail-conditioned water experiment.

    PubMed

    Gutiérrez, Alfredo; Yong, Mary; Wong, Lin; Sánchez, Jorge

    2002-09-01

    A snail-conditioned water experiment was conducted in Pseudosuccinea columella to test the possible role of a chemical interaction between snails on the diminished growth and fecundity rates found for snails raised in pairs compared to those raised in complete isolation. The results permit to discard the hypothesis of an inhibition of growth and reproduction between snails due to factors released into the water. PMID:12386712

  7. Survival of the Faucet Snail after Chemical Disinfection, pH extremes, and Heated Water Bath Treatments

    Microsoft Academic Search

    Andrew J. Mitchell; Rebecca A. Cole

    2008-01-01

    The faucet snail Bithynia tentaculata, a nonindigenous aquatic snail from Eurasia, was introduced into Lake Michigan in 1871 and has spread to the mid-Atlantic states, the Great Lakes region, Montana, and most recently, the Mississippi River. The faucet snail serves as intermediate host for several trematodes that have caused large-scale mortality among water birds, primarily in the Great Lakes region

  8. Supercharged Snails for Stream Ecology & Water-Quality Studies

    ERIC Educational Resources Information Center

    Stewart, Arthur J.; Ryon, Michael G.

    2003-01-01

    Gill-breathing freshwater snails (Family "Pleuroceridae") are ecologically important, abundant in many streams in the United States, and easy to collect and maintain under classroom conditions. These snails can be used in classroom tests to demonstrate effects of pollutants on aquatic organisms. In more advanced classes, students can cage the…

  9. Wet Adhesion and Adhesive Locomotion of Snails on AntiAdhesive Non-Wetting Surfaces

    Microsoft Academic Search

    Neil J. Shirtcliffe; Glen McHale; Michael I. Newton

    2012-01-01

    Creating surfaces capable of resisting liquid-mediated adhesion is extremely difficult due to the strong capillary forces that exist between surfaces. Land snails use this to adhere to and traverse across almost any type of solid surface of any orientation (horizontal, vertical or inverted), texture (smooth, rough or granular) or wetting property (hydrophilic or hydrophobic) via a layer of mucus. However,

  10. Surface Water

    NSDL National Science Digital Library

    This is the USGS Water Science for School's page and the topic is surface water. Explained are surface water use, importance, rivers and streams. Also answers the questions of what is runoff, how is the flow of a stream measured, how does stream height relate to flow and much, much more.

  11. Stable isotope composition of land snail body water and its relation to environmental waters and shell carbonate

    SciTech Connect

    Goodfriend, G.A.; Magaritz, M.; Gat, J.R. (Weizmann Institute of Science, Rehovot (Israel))

    1989-12-01

    Day-to-day and within-day (diel) variations in {delta}D and {delta}{sup 18}O of the body water of the land snail, Theba pisana, were studied at a site in the southern coastal plain of Israel. Three phases of variation, which relate to isotopic changes in atmospheric water vapor, were distinguished. The isotopic variations can be explained by isotopic equilibration with atmospheric water vapor and/or uptake of dew derived therefrom. During the winter, when the snails are active, there is only very minor enrichment in {sup 18}O relative to equilibrium with water vapor or dew, apparently as a result of metabolic activity. But this enrichment becomes pronounced after long periods of inactivity. Within-day variation in body water isotopic composition is minor on non-rain days. Shell carbonate is enriched in {sup 18}O by ca. 1-2% relative to equilibrium with body water. In most regions, the isotopic composition of atmospheric water vapor (or dew) is a direct function of that of rain. Because the isotopic composition of snail body water is related to that of atmospheric water vapor and the isotopic composition of shell carbonate in turn is related to that of body water, land snail shell carbonate {sup 18}O should provide a reliable indication of rainfall {sup 18}O. However, local environmental conditions and the ecological properties of the snail species must be taken into account.

  12. Influence of water quality on zinc toxicity to the Florida apple snail (Pomacea paludosa) and sensitivity of freshwater snails to zinc.

    PubMed

    Hoang, Tham C; Tong, Xin

    2015-03-01

    The present study characterized the influence of water-quality characteristics on zinc (Zn) toxicity to the Florida apple snail (Pomacea paludosa) and the sensitivity of freshwater snails to Zn. Standard 96-h renewal acute toxicity tests were conducted with Zn and juvenile P. paludosa under 3 conditions of pH and alkalinity, water hardness, and dissolved organic carbon (DOC). Median lethal effect concentrations (96-h LC50s), no-observed- effect concentrations, lowest-observed-effect concentrations, LC10s, and LC20s were determined for each test. The results showed that Zn toxicity to P. paludosa decreased linearly with increasing hardness, pH, and DOC. A multiple linear regression model based on pH, hardness, and DOC was able to explain 99% of the observed variability in LC50s. These results are useful for the development of a biotic ligand model (BLM) for P. paludosa and Zn. Zinc acute toxicity data were collected from the literature for 12 freshwater snail species in a wide range of water-quality characteristics for species sensitivity distribution analysis. The results showed that P. paludosa is the second most sensitive to Zn. The present study also suggested that aqueous ZnCO3 and ZnHCO3 (-) can be bioavailable to P. paludosa. Therefore, bioavailability models (e.g., BLM) should take these Zn species into consideration for bioavailability when applied to snails. PMID:25475172

  13. Use of ice water and salt treatments to eliminate an exotic snail, red-rim melania Melanoides tuberculatus, from small immersible fisheries equipment

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Ice water and salt treatments were evaluated for disinfection of fisheries equipment contaminated with a non-indigenous tropical snail, the red-rim melania Melanoides tuberculatus. The snail can displace native snails and can transmit trematodes directly to fishes and indirectly to other animals, i...

  14. Effect of water plants and non-target snails on the infectivity of Bulinus truncatus with Schistosoma haematobium.

    PubMed

    Bakry, Fayez A; Abd-el-Monem, Sayed

    2005-12-01

    The application of the water plant (Ceratophyllum demersum, Eichhornia crassipes and Lemna gibba) and/or non-target snails (Planorbis planorbis, Physa acuta and Melanoides tuberculata) gave a significant degree of reduction in the infection rate of B. truncatus subjected to S. haematobium miracidia. The data also indicated a reduction in mean total number of cercarial production/snail. However, no significant difference was detected in the prepatent period and duration of cercarial shedding of the parasite when compared with the control group. So, the results revealed that the snails exhibited a competitive ability against B. truncatus. Both survival rate and egg production of B. truncatus were greatly reduced when existed in mixed cultures with non-target snails and the magnitude of this reduction increased by increasing the number of the non-target snails. PMID:16333895

  15. Survival of the faucet snail after chemical disinfection, pH extremes, and heated water bath treatments

    USGS Publications Warehouse

    Mitchell, A.J.; Cole, R.A.

    2008-01-01

    The faucet snail Bithynia tentaculata, a nonindigenous aquatic snail from Eurasia, was introduced into Lake Michigan in 1871 and has spread to the mid-Atlantic states, the Great Lakes region, Montana, and most recently, the Mississippi River. The faucet snail serves as intermediate host for several trematodes that have caused large-scale mortality among water birds, primarily in the Great Lakes region and Montana. It is important to limit the spread of the faucet snail; small fisheries equipment can serve as a method of snail distribution. Treatments with chemical disinfection, pH extremes, and heated water baths were tested to determine their effectiveness as a disinfectant for small fisheries equipment. Two treatments eliminated all test snails: (1) a 24-h exposure to Hydrothol 191 at a concentration of at least 20 mg/L and (2) a treatment with 50??C heated water for 1 min or longer. Faucet snails were highly resistant to ethanol, NaCl, formalin, Lysol, potassium permanganate, copper sulfate, Baquacil, Virkon, household bleach, and pH extremes (as low as 1 and as high as 13).

  16. An artificial perch to help Snail Kites handle an exotic Apple Snail

    USGS Publications Warehouse

    Pias, Kyle E.; Welch, Zach C.; Kitchens, Wiley M.

    2012-01-01

    In the United States, the Snail Kite (Rostrhamus sociabilis plumbeus) is a federally endangered species and restricted to the wetlands of south-central Florida where the current population numbers less than 1,500. The Snail Kite is an extreme dietary specialist, previously feeding almost exclusively on one species of snail, the Florida Apple Snail (Pomacea paludosa). Within the past decade, an exotic species of apple snail, the Island Apple Snail (Pomacea insularum), has become established on lakes in central Florida. Island Apple Snails are larger than the native Florida Apple Snails, and Snail Kites handle the exotic snails less efficiently. Juvenile Snail Kites, in particular, have lower daily energy balances while feeding on Island Apple Snails. An inexpensive, easy-to-construct platform was developed that would provide Snail Kites with a flat, stable surface on which to extract snails. The platform has the potential to reduce the difficulties Snail Kites experience when handling exotic snails, and may benefit the Snail Kite population as a whole. Initial observations indicate that Snail Kites use the platforms frequently, and snails extracted at the platforms are larger than snails extracted at other perches.

  17. Three Gorges Dam: Impact of Water Level Changes on the Density of Schistosome-Transmitting Snail Oncomelania hupensis in Dongting Lake Area, China

    PubMed Central

    Wu, Jin-Yi; Zhou, Yi-Biao; Chen, Yue; Liang, Song; Li, Lin-Han; Zheng, Sheng-Bang; Zhu, Shao-ping; Ren, Guang-Hui; Song, Xiu-Xia; Jiang, Qing-Wu

    2015-01-01

    Background Schistosomiasis remains an important public health issue in China and worldwide. Oncomelania hupensis is the unique intermediate host of schistosoma japonicum, and its change influences the distribution of S. japonica. The Three Gorges Dam (TGD) has substantially changed the ecology and environment in the Dongting Lake region. This study investigated the impact of water level and elevation on the survival and habitat of the snails. Methods Data were collected for 16 bottomlands around 4 hydrological stations, which included water, density of living snails (form the Anxiang Station for Schistosomiasis Control) and elevation (from Google Earth). Based on the elevation, sixteen bottomlands were divided into 3 groups. ARIMA models were built to predict the density of living snails in different elevation areas. Results Before closure of TGD, 7 out of 9 years had a water level beyond the warning level at least once at Anxiang hydrological station, compared with only 3 out of 10 years after closure of TGD. There were two severe droughts that happened in 2006 and 2011, with much fewer number of flooding per year compared with other study years. Overall, there was a correlation between water level changing and density of living snails variation in all the elevations areas. The density of living snails in all elevations areas was decreasing after the TGD was built. The relationship between number of flooding per year and the density of living snails was more pronounced in the medium and high elevation areas; the density of living snails kept decreasing from 2003 to 2014. In low elevation area however, the density of living snails decreased after 2003 first and turned to increase after 2011. Our ARIMA prediction models indicated that the snails would not disappear in the Dongting Lake region in the next 7 years. In the low elevation area, the density of living snails would increase slightly, and then stabilize after the year 2017. In the medium elevation region, the change of the density of living snails would be more obvious and would increase till the year 2020. In the high elevation area, the density of living snails would remain stable after the year 2015. Conclusion The TGD influenced water levels and reduced the risk of flooding and the density of living snails in the study region. Based on our prediction models, the density of living snails in all elevations tends to be stabilized. Control of S. japonica would continue to be an important task in the study area in the coming decade. PMID:26114956

  18. A comparison of metal levels and antioxidant enzymes in freshwater snails, Lymnaea natalensis, exposed to sediment and water collected from Wright Dam and Lower Mguza Dam, Bulawayo, Zimbabwe.

    PubMed

    Siwela, A H; Nyathi, C B; Naik, Y S

    2010-10-01

    We compared the bioaccumulation of lead (Pb), cadmium (Cd), zinc (Zn), copper (Cu), nickel (Ni) and iron (Fe) with antioxidant enzyme activity in tissues of the snails, Lymnaea natalensis, exposed to elements of two differently polluted dams. 45 snails were exposed to sediment and water collected from Wight Dam (reference) whilst another 45 snails were also exposed to sediment and water collected from Lower Mguza Dam (polluted dam). Except for Fe in sediment and Pb in water, metal concentrations were statistically higher in sediment and water collected from Lower Mguza Dam. Lead, Cd and Zn were two times higher in tissues of snails exposed to Lower Mguza Dam elements. On one hand, superoxide dismutase (SOD), diphosphotriphosphodiaphorase (DTD) and catalase (CAT) activities were significantly lower whilst malondialdehyde (MDA) levels were significantly higher in tissues of snails exposed to Lower Mguza Dam sediment and water. On the other hand, selenium-dependent glutathione peroxidase (Se-GPX) activity was significantly elevated in tissues of snails exposed to Lower Mguza Dam sediment and water. Snails exposed to Lower Mguza Dam elements seem to have responded to pollution by increasing CAT and Se-GPX specific activity in an effort to detoxify peroxides produced as a result of metal induced oxidative stress. PMID:20813407

  19. Mineral contents of tissues and body fluids and heavy metal contaminants of four predominant snail species in the Niger Delta

    Microsoft Academic Search

    H. D. Mepba; C. U. Ogunka-Nnoka

    Mineral contents and heavy metal contaminants of four predominant snail species in the Niger Delta: African giant land snail (Archachatina marginata), African land snail (Achatina fulica), water snail (Pila ovata) and garden snail (Limicolaria aurora) were evaluated. Snail tissues and body fluids were harvested having cracked the tail-end of the shell. Triplicate samples of macerated snail tissues and body fluids

  20. Dry down impacts on apple snail (Pomacea paludosa) demography: Implications for wetland water management

    USGS Publications Warehouse

    Darby, P.C.; Bennetts, R.E.; Percival, H.F.

    2008-01-01

    Florida apple snails (Pomacea paludosa Say) are prey for several wetland-dependent predators, most notably for the endangered Florida snail kite (Rostrhamus sociabilis Vieillot). Management concerns for kites have been raised regarding the impacts of wetland dry downs on snails, but little data exists to validate these concerns. We simulated drying events in experimental tanks, where we observed that snail survival patterns, regardless of hydrology, were driven by a post-reproductive die off. In contrast to earlier reports of little to no dry down tolerance, we found that 70% of pre-reproductive adult-sized snails survived a 12-week dry down. Smaller size classes of snails exhibited significantly lower survival rates (< 50% after eight weeks dry). Field surveys showed that 77% of egg production occurs in April-June. Our hydrologic analyses of six peninsular Florida wetlands showed that most dry downs overlapped a portion of the peak snail breeding season, and 70% of dry downs were ??? 12 weeks in duration. Dry down timing can affect recruitment by truncating annual egg production and stranding juveniles. Dry down survival rates and seasonal patterns of egg cluster production helped define a range of hydrologic conditions that support robust apple snail populations, and illustrate why multiple characteristics of dry down events should be considered in developing target hydrologic regimes for wetland fauna. ?? 2008, The Society of Wetland Scientists.

  1. Implications of water hardness in ecotoxicological assessments for water quality regulatory purposes: a case study with the aquatic snail Biomphalaria glabrata (Say, 1818).

    PubMed

    Oliveira-Filho, E C; Caixeta, N R; Simplício, N C S; Sousa, S R; Aragão, T P; Muniz, D H F

    2014-02-01

    Water hardness is a property depending on the presence of alkaline earth metals, mainly calcium and magnesium. Among the strategies for water quality monitoring, ecotoxicological assays are performed to minimize impacts and classify water bodies. For these laboratory evaluations parameters are previously defined in the guidelines, including water hardness for both cultivation and testing medium. The present work was performed to evaluate the effects of different levels of water hardness on the survival and reproduction of the freshwater snail Biomphalaria glabrata and discuss the influence of natural water hardness on the results of ecotoxicological tests with these environmental samples. Comparing the groups it was possible to observe that those maintained in waters with least hardness had lower reproductive success, while the groups maintained in highest hardness showed better reproduction. These data show that waters with low hardness make the reproduction of the snail B. glabrata unfeasible, and this reveal a problem for ecotoxicity assays using natural water samples. PMID:25055099

  2. Is water temperature responsible for geographic variation in shell mass of Littorina obtusata (L.) snails in the Gulf of Maine?

    Microsoft Academic Search

    Sean Doyle; Bruce MacDonald; Rémy Rochette

    2010-01-01

    A latitudinal cline in length-standardized shell thickness and mass of Littorina obtusata in the Gulf of Maine (GoM) has been attributed to predation by the European green crab Carcinus maenas. However, latitudinal variation in water temperature may also contribute to this cline. To investigate this hypothesis, we grew snails from 2 thin-shelled and 2 thick-shelled populations in warm (16°C) and

  3. The Effects of Water Quality and Age on the Acute Toxicity of Copper to the Florida Apple Snail, Pomacea paludosa

    Microsoft Academic Search

    E. C. Rogevich; T. C. Hoang; G. M. Rand

    2008-01-01

    Copper (Cu)-containing compounds have been used in Florida as fungicides, herbicides, and soil amendments, resulting in elevated\\u000a Cu in the aquatic ecosystem. The Florida apple snail (Pomacea paludosa), a key species in south Florida, may be adversely affected by Cu. Water-quality parameters, such as hardness, dissolved\\u000a organic carbon (DOC), pH, and alkalinity, affect metal bioavailability and toxicity in aquatic organisms;

  4. Use of Ice-Water and Salt Treatments to Eliminate an Exotic Snail, the Red-Rim Melania, from Small Immersible Fisheries Equipment

    Microsoft Academic Search

    Andrew J. Mitchell; Thomas M. Brandt

    2009-01-01

    Ice-water and salt treatments were evaluated for disinfection of small immersible fisheries equipment contaminated with a nonindigenous tropical snail, the red-rim melania Melanoides tuberculatus. This introduced species can displace native snails and transmit trematodes directly to fish and indirectly to other animals, including humans. The red-rim melania has a well-developed operculum that protects it from desiccation and allows it to

  5. Survival and behavior of Chinese mystery snails (Bellamya chinensis) in response to simulated water body drawdowns and extended air exposure

    USGS Publications Warehouse

    Unstad, Kody M.; Uden, Daniel R.; Allen, Craig R.; Chaine, Noelle M.; Haak, Danielle M.; Kill, Robert A.; Pope, Kevin L.; Stephen, Bruce J.; Wong, Alec

    2013-01-01

    Nonnative invasive mollusks degrade aquatic ecosystems and induce economic losses worldwide. Extended air exposure through water body drawdown is one management action used for control. In North America, the Chinese mystery snail (Bellamya chinensis) is an invasive aquatic snail with an expanding range, but eradication methods for this species are not well documented. We assessed the ability of B. chinensis to survive different durations of air exposure, and observed behavioral responses prior to, during, and following desiccation events. Individual B. chinensis specimens survived air exposure in a laboratory setting for > 9 weeks, and survivorship was greater among adults than juveniles. Several B. chinensis specimens responded to desiccation by sealing their opercula and/or burrowing in mud substrate. Our results indicate that drawdowns alone may not be an effective means of eliminating B. chinensis. This study lays the groundwork for future management research that may determine the effectiveness of drawdowns when combined with factors such as extreme temperatures, predation, or molluscicides.

  6. Survival of the faucet snail Bithynia tentaculata after chemical disinfection, pH extremes, and heated water bath treatments

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Bithynia tentaculata, the faucet snail, is a non indigenous aquatic snail from Eurasia that was introduced into Lake Michigan in 1871. The snail’s distribution in the United States has expanded to the mid-Atlantic states and the drainage basin of the Great Lakes and most recently to the Mississippi...

  7. O-Glycosylation of snails.

    PubMed

    Stepan, Herwig; Pabst, Martin; Altmann, Friedrich; Geyer, Hildegard; Geyer, Rudolf; Staudacher, Erika

    2012-05-01

    The glycosylation abilities of snails deserve attention, because snail species serve as intermediate hosts in the developmental cycles of some human and cattle parasites. In analogy to many other host-pathogen relations, the glycosylation of snail proteins may likewise contribute to these host-parasite interactions. Here we present an overview on the O-glycan structures of 8 different snails (land and water snails, with or without shell): Arion lusitanicus, Achatina fulica, Biomphalaria glabrata, Cepaea hortensis, Clea helena, Helix pomatia, Limax maximus and Planorbarius corneus. The O-glycans were released from the purified snail proteins by ?-elimination. Further analysis was carried out by liquid chromatography coupled to electrospray ionization mass spectrometry and - for the main structures - by gas chromatography/mass spectrometry. Snail O-glycans are built from the four monosaccharide constituents: N-acetylgalactosamine, galactose, mannose and fucose. An additional modification is a methylation of the hexoses. The common trisaccharide core structure was determined in Arion lusitanicus to be N-acetylgalactosamine linked to the protein elongated by two 4-O-methylated galactose residues. Further elongations by methylated and unmethylated galactose and mannose residues and/or fucose are present. The typical snail O-glycan structures are different to those so far described. Similar to snail N-glycan structures they display methylated hexose residues. PMID:22581130

  8. MINE DEVELOPMENT SURFACE WATER

    E-print Network

    Boisvert, Jeff

    Mine Engineering Plan Surface Water Components Site Drainage Mine Site Dewatering (If covered Dewatering Open Pit Lake Drain site / Water Disposal Mine Site Runoff Dikes Seepage Underground Mine Rivers

  9. FACTORS AFFECTING HATCHING SUCCESS OF GOLDEN APPLE SNAIL EGGS: EFFECTS OF WATER IMMERSION AND CANNIBALISM

    E-print Network

    Siemann, Evan

    -mail: khorn@rice.edu Abstract: The golden apple snail (Pomacea maculata Perry) is an invasive species, invasive management, invasive species, Pomacea INTRODUCTION Invasive species are present in many ecosystems, Henderson et al. 2006). Invasive species impact community composition and habitat struc- ture in both

  10. Developmental toxicity, acute toxicity and mutagenicity testing in freshwater snails Biomphalaria glabrata (Mollusca: Gastropoda) exposed to chromium and water samples.

    PubMed

    Tallarico, Lenita de Freitas; Borrely, Sueli Ivone; Hamada, Natália; Grazeffe, Vanessa Siqueira; Ohlweiler, Fernanda Pires; Okazaki, Kayo; Granatelli, Amanda Tosatte; Pereira, Ivana Wuo; Pereira, Carlos Alberto de Bragança; Nakano, Eliana

    2014-12-01

    A protocol combining acute toxicity, developmental toxicity and mutagenicity analysis in freshwater snail Biomphalaria glabrata for application in ecotoxicological studies is described. For acute toxicity testing, LC50 and EC50 values were determined; dominant lethal mutations induction was the endpoint for mutagenicity analysis. Reference toxicant potassium dichromate (K2Cr2O7) was used to characterize B. glabrata sensitivity for toxicity and cyclophosphamide to mutagenicity testing purposes. Compared to other relevant freshwater species, B. glabrata showed high sensitivity: the lowest EC50 value was obtained with embryos at veliger stage (5.76mg/L). To assess the model applicability for environmental studies, influent and effluent water samples from a wastewater treatment plant were evaluated. Gastropod sensitivity was assessed in comparison to the standardized bioassay with Daphnia similis exposed to the same water samples. Sampling sites identified as toxic to daphnids were also detected by snails, showing a qualitatively similar sensitivity suggesting that B. glabrata is a suitable test species for freshwater monitoring. Holding procedures and protocols implemented for toxicity and developmental bioassays showed to be in compliance with international standards for intra-laboratory precision. Thereby, we are proposing this system for application in ecotoxicological studies. PMID:25259848

  11. The Effect of Simulating Different Intermediate Host Snail Species on the Link between Water Temperature and Schistosomiasis Risk

    PubMed Central

    McCreesh, Nicky; Booth, Mark

    2014-01-01

    Introduction A number of studies have attempted to predict the effects of climate change on schistosomiasis risk. The importance of considering different species of intermediate host snails separately has never previously been explored. Methods An agent-based model of water temperature and Biomphalaria pfeifferi population dynamics and Schistosoma mansoni transmission was parameterised to two additional species of snail: B. glabrata and B. alexandrina. Results Simulated B. alexandrina populations had lower minimum and maximum temperatures for survival than B. pfeifferi populations (12.5–29.5°C vs. 14.0–31.5°C). B. glabrata populations survived over a smaller range of temperatures than either B. pfeifferi or B. alexandrina (17.0°C–29.5°C). Infection risk peaked at 16.5°C, 25.0°C and 19.0°C respectively when B. pfeifferi, B. glabrata and B. alexandrina were simulated. For all species, infection risk increased sharply once a minimum temperature was reached. Conclusions The results from all three species suggest that infection risk may increase dramatically with small increases in temperature in areas at or near the currents limits of schistosome transmission. The effect of small increases in temperature in areas where schistosomiasis is currently found will depend both on current temperatures and on the species of snail acting as intermediate host(s) in the area. In most areas where B. pfeifferi is the host, infection risk is likely to decrease. In cooler areas where B. glabrata is the host, infection risk may increase slightly. In cooler areas where B. alexandrina is the host, infection risk may more than double with only 2°C increase in temperature. Our results show that it is crucial to consider the species of intermediate host when attempting to predict the effects of climate change on schistosomiasis. PMID:24988377

  12. Bactericidal action of a glycoprotein from the body surface mucus of giant African snail.

    PubMed

    Otsuka-Fuchino, H; Watanabe, Y; Hirakawa, C; Tamiya, T; Matsumoto, J J; Tsuchiya, T

    1992-04-01

    1. Bactericidal action of a glycoprotein, Achacin, purified from the giant African snail, Achatina fulica Férussac, has been studied. 2. Achacin kills both gram-positive and gram-negative bacteria, but only in their growing states. 3. Achacin does not have any bacteriolytic activity. 4. The strain which has no cell wall is a little more sensitive than the native strain and the cell membrane-damaged strain. 5. Achacin was observed on the cytoplasmic membrane and on the cell wall of treated Escherichia coli by immunoelectron microscopy. 6. Achacin attacks the cytoplasmic membrane of the cell. PMID:1379901

  13. HPTLC Determination of Amino Acids in Snail-Conditioned Water From Biomphalaria glabrata, Two Strains of Helisoma trivolvis, and Lymnaea elodes

    Microsoft Academic Search

    R. A. Steiner; B. Fried; J. Sherma

    1998-01-01

    High performance thin-layer chromatography (HPTLC) was used to analyze amino acids in water conditioned by Biomphalaria glabrata, a Pennsylvania and Colorado strain of Helisoma trivolvis, and Lymnaea elodes. The snail-conditioned water (SCW) samples were dried with air and reconstituted in 10% n-propanol and then applied to cellulose HPTLC plates and developed with n-propanol-water (7:3). Amino acids were detected with ninhydrin

  14. SURFACE WATER & OCEAN TOPOGRAPHY

    E-print Network

    Christian, Eric

    of the Wide Swath Ocean Altimeter (WSOA) and the Shuttle Radar Topography Mission (SRTM). The Ku-band sampling for surface-water applications, near-global coverage, and the swath capabilities of the Ku-band/JPL ­ IIP98) · Enhancement of key technologies (Ka-band radar interferometry antenna design, onboard

  15. Texas Surface Water Quality Standards

    E-print Network

    Biological evaluation Institutional evaluation · Permitted discharges · Water rights Conclusions References1 Texas Surface Water Quality Standards 30 TAC Chapter 307 Lori Hamilton Water Quality Standards) -Assessment of the physical, chemical, biological, and economic factors affecting attainment of a water body

  16. Influence of an extreme high water event on survival, reproduction, and distribution of snail kites in Florida, USA

    USGS Publications Warehouse

    Bennetts, R.E.; Kitchens, W.M.; Dreitz, V.J.

    2002-01-01

    Hydrology frequently has been reported as the environmental variable having the greatest influence on Florida snail kite (Rostrhamus sociabilis) populations. Although drought has received the most attention, high-water conditions also have been reported to affect kites. Years of high water generally have been reported to be favorable for nesting, although prolonged high water may be detrimental to sustaining suitable habitat. During 1994 and 1995, southern Florida experienced an extreme high water event. This event enabled us to compare survival, nesting success, number of young per successful nest, and spatial distribution of nesting before, during, and after the event. We found no evidence of an effect (either negative or positive) on survival of adult kites. In contrast, juvenile kites experienced the highest survival during the event, although our data suggest greater annual variability than can be explained by the event alone. We found no evidence of an effect of the high water event on nest success or number of young per successful nest. Nest success was highest during the event in the southern portion of the range but was quite similar to other years, both before and after the event. Our data do indicate a substantial shift in the spatial distribution of nesting birds. During the event, nesting activity shifted to higher elevations (i.e., shallower water) in the major nesting areas of the Everglades region. Nesting also occurred in Big Cypress National Preserve during the event, which is typically too dry to support nesting kites. Thus, our data indicate a potential short-term benefit of increased juvenile survival and an expansion of nesting habitat. However, the deterioration of habitat quality from prolonged high water precludes any recommendation for such conditions to be maintained for extended periods. ?? 2002, The Society of Wetland Scientists.

  17. Chemo-orientation of echinostome cercariae towards their snail hosts: the stimulating structure of amino acids and other attractants

    Microsoft Academic Search

    Martina Körner; Wilfried Haas

    1998-01-01

    The cercariae of Pseudechinoparyphium echinatum and Echinostoma revolutum locate their host snails by turning back when swimming in decreasing gradients of the small molecular weight fraction (< 500) of snail conditioned water. Fractionation and chemical modifications of snail conditioned water from Lymnaea stagnalis showed that amino acids are necessary for the stimulating activity of snail conditioned water. A complete mixture

  18. Production of apple snail for space diet

    NASA Astrophysics Data System (ADS)

    Yamashita, Masamichi; Motoki, Shigeru; Space Agriculture Task Force, J.; Katayama, Naomi

    For food production in space at recycling bio-elements under closed environment, appropriate organisms should be chosen to drive the closed materials recycle loop. We propose a combination of green algae, photosynthetic protozoa, and aquatic plants such as Wolffia spp., for the primary producer fixing solar energy to chemical form in biomass, and apple snail, Pomacea bridgesii, which converts this biomass to animal meat. Because of high proliferation rate of green algae or protozoa compared to higher plants, and direct conversion of them to apple snail, the efficiency of food production in this combination is high, in terms of energy usage, space for rearing, and yield of edible biomass. Furthermore, green algae and apple snail can form a closed ecological system with exchanging bio-elements between two member, i.e. excreta of snail turn to fertilizer of algae, and grown algae become feed for snail. Since apple snail stays in water or on wet substrate, control of rearing is easy to make. Mass production technology of apple snail has been well established to utilize it as human food. Nutrients of apple snail are also listed in the standard tables of food composition in Japan. Nutrients for 100 g of apple snail canned in brine are energy 340 kJ, protein 16.5 g, lipid 1.0 g, cholesterol 240 mg, carbohydrate 0.8 g, Ca 400 mg, Fe 3.9 mg, Zn 1.5 mg. It is rich in minerals, especially Ca and Fe. Vitamin contents are quite low, but K 0.005 mg, B2 0.09 mg, B12 0.0006 mg, folate 0.001 mg, and E 0.6 mg. The amino acid score of apple snail could not be found in literature. Overall, apple snail provides rich protein and animal lipid such as cholesterol. It could be a good source of minerals. However, it does not give enough vitamin D and B12 , which are supposed to be supplemented by animal origin foods. In terms of acceptance in food culture, escargot is a gourmet menu in French dishes, and six to ten snail, roughly 50 g, are served for one person. Apple snail reaches to 30 g of body weight within two or three month from its egg. Several hundreds of egg are laid by one snail. It start egg laying after three months from hatching. In order to harvest 50 g for every day's meal, 3 m2 is required for rearing space. Eating apple snail and establishing its rearing system might save the food crisis on Earth.

  19. Foraging and refuge use by a pond snail: Effects of physiological state, predators, and resources

    NASA Astrophysics Data System (ADS)

    Wojdak, Jeremy M.

    2009-09-01

    The costs and benefits of anti-predator behavioral responses should be functions of the actual risk of predation, the availability of the prey's resources, and the physiological state of the prey. For example, a food-stressed individual risks starvation when hiding from predators, while a well-fed organism can better afford to hide (and pay the cost of not foraging). Similarly, the benefits of resource acquisition are probably highest for the prey in the poorest state, while there may be diminishing returns for prey nearing satiation. Empirical studies of state-dependent behavior are only beginning, however, and few studies have investigated interactions between all three potentially important factors. Here I present the results of a laboratory experiment where I manipulated the physiological state of pond snails ( Physa gyrina), the abundance of algal resources, and predation cues ( Belostoma flumineum waterbugs consuming snails) in a full factorial design to assess their direct effects on snail behavior and indirect effects on algal biomass. On average, snails foraged more when resources were abundant, and when predators were absent. Snails also foraged more when previously exposed to physiological stress. Snails spent more time at the water's surface (a refuging behavior) in the presence of predation cues on average, but predation, resource levels, and prey state had interactive effects on refuge use. There was a consistent positive trait-mediated indirect effect of predators on algal biomass, across all resource levels and prey states.

  20. Is the interspecific variation of body size of land snails correlated with rainfall in Israel and Palestine?

    NASA Astrophysics Data System (ADS)

    Hausdorf, Bernhard

    2006-11-01

    The hypothesis that body size of land snail species increases with aridity in Israel and Palestine because large snails lose relatively less water due to their lower surface to volume ratio has been investigated. Data on rainfall amplitudes of 84 land snail species in Israel and Palestine and on their body sizes were used to test for interspecific correlations between body size and rainfall. Four methods, means of body sizes in rainfall categories, the midpoint method, the across-species method, and a phylogenetically controlled analysis (CAIC) showed that there is no significant correlation between body size of land snail species and their rainfall amplitude in Israel and Palestine. The lack of an interspecific correlation between body size and rainfall amplitude may be the result of conflicting selective forces on body size.

  1. Apple Snails (Ampullariidae)

    NSDL National Science Digital Library

    Stijn A. I. Ghesquiere

    This web site provides information on apple snails (family Ampullariidae), the largest living freshwater snails on earth, often kept as aquarium pets because of their attractive appearance and size. Topics include the care of apple snails, their anatomy, species and genera, and information on snail pests, embryology, and genetics. There is also a frequently-asked-questions feature, photos, links to web sites and literature, and an online discussion forum.

  2. Sustaining dry surfaces under water

    E-print Network

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

    2014-09-29

    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.

  3. Regulation of laboratory populations of snails (Biomphalaria and Bulinus spp.) by river prawns, Macrobrachium spp. (Decapoda, Palaemonidae): implications for control of schistosomiasis.

    PubMed

    Sokolow, Susanne H; Lafferty, Kevin D; Kuris, Armand M

    2014-04-01

    Human schistosomiasis is a common parasitic disease endemic in many tropical and subtropical countries. One barrier to achieving long-term control of this disease has been re-infection of treated patients when they swim, bathe, or wade in surface fresh water infested with snails that harbor and release larval parasites. Because some snail species are obligate intermediate hosts of schistosome parasites, removing snails may reduce parasitic larvae in the water, reducing re-infection risk. Here, we evaluate the potential for snail control by predatory freshwater prawns, Macrobrachium rosenbergii and M. vollenhovenii, native to Asia and Africa, respectively. Both prawn species are high value, protein-rich human food commodities, suggesting their cultivation may be beneficial in resource-poor settings where few other disease control options exist. In a series of predation trials in laboratory aquaria, we found both species to be voracious predators of schistosome-susceptible snails, hatchlings, and eggs, even in the presence of alternative food, with sustained average consumption rates of 12% of their body weight per day. Prawns showed a weak preference for Bulinus truncatus over Biomphalaria glabrata snails. Consumption rates were highly predictable based on the ratio of prawn: snail body mass, suggesting satiation-limited predation. Even the smallest prawns tested (0.5-2g) caused snail recruitment failure, despite high snail fecundity. With the World Health Organization turning attention toward schistosomiasis elimination, native prawn cultivation may be a viable snail control strategy that offers a win-win for public health and economic development. PMID:24388955

  4. Land snail anatomy

    NSDL National Science Digital Library

    N/A N/A (None; )

    2006-06-17

    Land snails have a shell for protection. They have four tentacles, a foot, and a head and a tail region. The top set of tentacles are the snail's eyes. The bottom set of tentacles are what the snail uses to smell.

  5. The surface relaxation of water.

    PubMed

    Liu, Maoyuan; Beattie, James K; Gray-Weale, Angus

    2012-08-01

    We examine three possible explanations for the millisecond relaxation time of the dynamic surface tension of water: the diffusion of surfactant contaminants from the aqueous phase to the surface, the reorientation of surface water molecules' dipole moments, and the buildup of a charged surface layer of hydroxide ions. The relaxation time expected for hydroxide is by far the closest to the measured time. Our model for the surface layer agrees with static equilibrium experiments and, as we show here, predicts the relaxation time. The results strongly imply that the equilibrium surface of water is highly charged by a flow of hydroxide to the surface. The model predicts that neither diffusion nor autolysis dominates and shows that both processes are needed to describe the relaxation of the surface tension. We find a salt and pH dependence of the relaxation time and propose further experiments. PMID:22582761

  6. Snails and trematode infection after Indian Ocean tsunami in Phang-Nga Province, southern Thailand.

    PubMed

    Sri-Aroon, Pusadee; Chusongsang, Phiraphol; Chusongsang, Yupa; Pornpimol, Surinthwong; Butraporn, Piyarat; Lohachit, Chantima

    2010-01-01

    The tsunami and non-tsunami affected areas of Takua Pa District, Phang-Nga Province were investigated for fresh- and brackish-water snails that transmit human parasitic diseases during 2006 and 2007. Among 46 snail species found, 17 species of 8 families were freshwater snails, 28 species of another 7 families were brackish-water snails, and 1 species was a land snail. Of these species, 11 freshwater snails, 4 brackish-water snails and 1 land snail were of medical importance. The fresh-water snails were Pomacea canaliculata, Pila angelica, P. gracilis, P. polita, Filopaludina (S.) martensi, F. (F.) s. polygramma, Melanoides tuberculata, Indoplanorbis exuxtus, Radix rubiginosa, Helicorbis umbilicalis, Gyraulus convexiusculus. Four brackish-water snails were Cerithidea cingulata, C. djadjarensis, C. alata, Sermyla riqueti and Achatina fulica was the land snail. I. exutus, M. tuberculata and F. (F.) s. polygramma harbored Xiphidio, Microcercus, Furocercus, Echinostome cercariae, and cercaria without eyespots or tail with hair. Three species of brackish-water snails, Cerithidia cingulata, C. djadjariensis, and C. alata presented with 6 types of trematode cercariae and rediae. Knowledge of medically important snails and their parasitic diseases, and prevention were given to Takua Pa people by poster, pamphlets and broadcasting through community radio. PMID:20578482

  7. Bioaccumulation of heavy metals in water, sediments, aquatic plant and histopathological effects on the golden apple snail in Beung Boraphet reservoir, Thailand.

    PubMed

    Dummee, Vipawee; Kruatrachue, Maleeya; Trinachartvanit, Wachareeporn; Tanhan, Phanwimol; Pokethitiyook, Prayad; Damrongphol, Praneet

    2012-12-01

    Changes in the seasonal concentrations of heavy metals (Cu, Mn, Fe, Zn, Pb and Cd) were determined in water, sediments, snails (Pomacea canaliculata) and aquatic plants (Ipomoea aquatica) in three selected tributaries of the Beung Boraphet reservoir, Nakhon Sawan Province, central Thailand. Only Fe, Cu, Mn and Zn were detected by FAAS in all samples collected. The water quality of Beung Boraphet was medium clean with Fe, Mn, Cu and Zn concentrations well below internationally accepted limits. According to the criteria proposed for sediments by the EPA Region V, Zn and Mn concentrations were within the non-polluted range while Fe and Cu (wet season) concentrations fell into the class of severely polluted sediment. Both P. canaliculata and I. aquatica bioconcentrated more Mn in their tissues than were found in sediments, especially in the wet season. The results of Pearson correlation study and BCF values also indicated similar findings. Only Mn showed the importance of sediment-to-snail concentration and high BCF values in both snails and plants. P. canaliculata exposed to contaminated sediment for two months, showed higher accumulation of metals (Fe, Mn, Cu and Zn) in the digestive tracts and digestive glands than in the foot muscles. Histopathological changes included alterations in the epithelial lining of the digestive tracts, digestive glands and the gills. Loss of cilia and increase in mucous cells were observed in the digestive tracts and gills, while the digestive glands exhibited an increase of dark granules and basophilic cells, and dilation of digestive cells. The results indicated that both P. canaliculata and I. aquatica could be used as biomonitors of sedimentary metal contamination for the Beung Boraphet reservoir. PMID:23079739

  8. Water surface depth instrument

    NASA Technical Reports Server (NTRS)

    Davis, Q. C., IV

    1970-01-01

    Measurement gage provides instant visual indication of water depth based on capillary action and light diffraction in a group of solid, highly polished polymethyl methacrylate rods. Rod lengths are adjustable to measure various water depths in any desired increments.

  9. Surface Water Quality Standards 

    E-print Network

    Wythe, Kathy

    2007-01-01

    of the water quali- ty standards, the overall process is expected to contin- ue into 2009.? For some, Texas? standards for contact recreation are not appropriate for many water bodies on the impaired list. Aaron Wendt, Texas State Soil and Water...

  10. Cercarial Dermatitis Transmitted by Exotic Marine Snail

    PubMed Central

    Cohen, Andrew N.; James, David; Hui, Lucia; Hom, Albert; Loker, Eric S.

    2010-01-01

    Cercarial dermatitis (swimmer’s itch) is caused by the penetration of human skin by cercariae of schistosome parasites that develop in and are released from snail hosts. Cercarial dermatitis is frequently acquired in freshwater habitats, and less commonly in marine or estuarine waters. To investigate reports of a dermatitis outbreak in San Francisco Bay, California, we surveyed local snails for schistosome infections during 2005–2008. We found schistosomes only in Haminoea japonica, an Asian snail first reported in San Francisco Bay in 1999. Genetic markers place this schistosome within a large clade of avian schistosomes, but do not match any species for which there are genetic data. It is the second known schistosome species to cause dermatitis in western North American coastal waters; these species are transmitted by exotic snails. Introduction of exotic hosts can support unexpected emergence of an unknown parasite with serious medical or veterinary implications. PMID:20735918

  11. Toxic Effects of Cadmium on Reproduction, Development, and Hatching in the Freshwater Snail Lymnaea stagnalisfor Water Quality Monitoring

    Microsoft Academic Search

    Annette Gomot

    1998-01-01

    The freshwater snailLymnaea stagnaliswas exposed to cadmium concentrations of 0, 25, 50, 100, 200, and 400 ?g liter?1. The influence of this highly toxic metal on various stages of reproduction (number of egg masses, number of eggs, embryo development, and hatching) was studied. Egg production ceased at 400 ?g Cd2+liter?1and hatching was reduced to 0.4% with 200 ?g liter?1at 20°C.

  12. Copper uptake and depuration by juvenile and adult Florida apple snails ( Pomacea paludosa )

    Microsoft Academic Search

    Tham C. Hoang; Emily C. Rogevich; Gary M. Rand; Robert A. Frakes

    2008-01-01

    The present study characterized copper (Cu) uptake and depuration by juvenile and adult Florida apple snails (Pomacea paludosa) from water, soil, and diet. During a 28-day uptake period, juvenile apple snails were exposed to aqueous Cu and adult apple\\u000a snails were exposed to Cu-contaminated soil, water, and food. In the follow-up 14-day depuration period, both juvenile and\\u000a adult apple snails

  13. Measuring Surface Water From Space

    NASA Astrophysics Data System (ADS)

    Partsch, J.; Alsdorf, D.; Rodriguez, E.; Lettenmaier, D.; Mognard, N.; Participants, T.

    2006-12-01

    Surface fresh water is essential for life, yet we have surprisingly poor knowledge of the spatial and temporal dynamics of surface fresh water discharge and changes in storage globally. For example, we are unable to answer such basic questions as "What is the spatial and temporal variability of water stored on and near the surface of all continents?" Furthermore, key societal issues, such as the susceptibility of life to flood hazards, cannot be answered with the current global, in-situ networks designed to observe river discharge at points but not flood events. The measurements required to answer these hydrologic questions are surface water area, the elevation of the water surface (h), its slope (dh/dx), and temporal change (dh/dt). Advances in remote sensing hydrology, particularly over the past 10 years and even more recently, have demonstrated that these hydraulic variables can be measured reliably from orbiting platforms. Measurements of inundated area have been used to varying degrees of accuracy as proxies for discharge, but are successful only when in-situ data are available for calibration and fail to indicate the dynamic topography of water surfaces. Radar altimeters have a rich, multi-decadal history of successfully measuring elevations of the ocean surface and are now also accepted as capable tools for measuring h along orbital profiles crossing fresh water bodies. However, altimeters are profiling tools which, because of their orbital spacings, miss too many fresh water bodies to be useful hydrologically. High spatial resolution images of dh/dt have been observed with interferometric synthetic aperture radar (SAR), but the method requires emergent vegetation to scatter radar pulses back to the receiving antenna. Essentially, existing spaceborne methods have been used to measure components of surface water hydraulics, but none of the technologies can singularly supply the water volume and hydraulic measurements that are needed to accurately model the water cycle and to guide water management practices. Instead, a combined imaging and elevation measuring approach is ideal as demonstrated by the Shuttle Radar Topography Mission (SRTM), which collected images of h at a high spatial resolution (~90m, thus permitting the calculation of dh/dx). We suggest that a future satellite concept, the Water And Terrestrial Elevation Recovery mission (WATER), will improve upon the SRTM design to permit multi-temporal mappings of h across the world's wetlands, floodplains, lakes, reservoirs, and rivers. state.edu/water/

  14. Sources of Water Surface water and groundwater are present throughout

    E-print Network

    MacAdam, Keith

    miles. Surface water occurs as rivers, streams, ponds, lakes, and wetlands. Ground- water occurs public supply systems provide water for 80 percent of the population. Water Contamination SurfaceSources of Water Surface water and groundwater are present throughout Kentucky's 39,486 square

  15. Measuring surface water from space

    NASA Astrophysics Data System (ADS)

    Alsdorf, Douglas E.; RodríGuez, Ernesto; Lettenmaier, Dennis P.

    2007-06-01

    Surface fresh water is essential for life, yet we have surprisingly poor knowledge of the spatial and temporal dynamics of surface freshwater discharge and changes in storage globally. For example, we are unable to answer such basic questions as "What is the spatial and temporal variability of water stored on and near the surface of all continents?" Furthermore, key societal issues, such as the susceptibility of life to flood hazards, cannot be answered with the current global, in situ networks designed to observe river discharge at points but not flood events. The measurements required to answer these hydrologic questions are surface water area, the elevation of the water surface (h), its slope (?h/?x), and temporal change (?h/?t). Advances in remote sensing hydrology, particularly over the past 10 years and even more recently, have demonstrated that these hydraulic variables can be measured reliably from orbiting platforms. Measurements of inundated area have been used to varying degrees of accuracy as proxies for discharge but are successful only when in situ data are available for calibration; they fail to indicate the dynamic topography of water surfaces. Radar altimeters have a rich, multidecadal history of successfully measuring elevations of the ocean surface and are now also accepted as capable tools for measuring h along orbital profiles crossing freshwater bodies. However, altimeters are profiling tools, which, because of their orbital spacings, miss too many freshwater bodies to be useful hydrologically. High spatial resolution images of ?h/?t have been observed with interferometric synthetic aperture radar, but the method requires emergent vegetation to scatter radar pulses back to the receiving antenna. Essentially, existing spaceborne methods have been used to measure components of surface water hydraulics, but none of the technologies can singularly supply the water volume and hydraulic measurements that are needed to accurately model the water cycle and to guide water management practices. Instead, a combined imaging and elevation-measuring approach is ideal as demonstrated by the Shuttle Radar Topography Mission (SRTM), which collected images of h at a high spatial resolution (˜90 m) thus permitting the calculation of ?h/?x. We suggest that a future satellite concept, the Water and Terrestrial Elevation Recovery mission, will improve upon the SRTM design to permit multitemporal mappings of h across the world's wetlands, floodplains, lakes, reservoirs, and rivers.

  16. The Effect of Aquatic Plant Abundance on Shell Crushing Resistance in a Freshwater Snail

    E-print Network

    Johnson, Steven G.

    The Effect of Aquatic Plant Abundance on Shell Crushing Resistance in a Freshwater Snail Johel matter that snails eat is related to the strength of their shells. We measured shell crushing resistance that can affect crushing resistance, such as the density of crushing predators, snail density, water p

  17. All About Snails

    NSDL National Science Digital Library

    2001-11-01

    This website introduces younger students to snails. Topics include their physical characteristics and living habits, diet, reproduction, locomotion, life history, predators, and many others. There are also links to additional material on snails, including lesson plans, stories, poems, and songs, clip-art, art and craft activties, and other resources.

  18. Persisting water droplets on water surfaces.

    PubMed

    Klyuzhin, Ivan S; Ienna, Federico; Roeder, Brandon; Wexler, Adam; Pollack, Gerald H

    2010-11-11

    Droplets of various liquids may float on the respective surfaces for extended periods of time prior to coalescence. We explored the features of delayed coalescence in highly purified water. Droplets several millimeters in diameter were released from a nozzle onto a water surface. Results showed that droplets had float times up to hundreds of milliseconds. When the droplets did coalesce, they did so in stepwise fashion, with periods of quiescence interspersed between periods of coalescence. Up to six steps were noted before the droplet finally vanished. Droplets were released in a series, which allowed the detection of unexpected abrupt float-time changes throughout the duration of the series. Factors such as electrostatic charge, droplet size, and sideways motion had considerable effect on droplet lifetime, as did reduction of pressure, which also diminished the number of steps needed for coalescence. On the basis of present observations and recent reports, a possible mechanism for noncoalescence is considered. PMID:20961076

  19. Groundwater and surface water pollution

    SciTech Connect

    Chae, Y.S.; Hamidi, A. [eds.

    2000-07-01

    This book contains almost all the technical know-how that is required to clean up the water supply. It provides a survey of up-to-date technologies for remediation, as well as a step-by-step guide to pollution assessment for both ground and surface waters. In addition to focusing on causes, effects, and remedies, the book stresses reuse, recycling, and recovery of resources. The authors suggest that through total recycling wastes can become resources.

  20. Neuron, Vol. 32, 173176, October 25, 2001, Copyright 2001 by Cell Press Of Snakes, Snails, and Surrogates

    E-print Network

    Kasher, Roni

    Neuron, Vol. 32, 173­176, October 25, 2001, Copyright 2001 by Cell Press Previews Of Snakes, Snails that are conservative substitutes.water snail. The kraits and other elapid snakes lunch on vertebrate prey

  1. An ecological study of Bithynia snails, the first intermediate host of Opisthorchis viverrini in northeast Thailand.

    PubMed

    Wang, Yi-Chen; Ho, Richard Cheng Yong; Feng, Chen-Chieh; Namsanor, Jutamas; Sithithaworn, Paiboon

    2015-01-01

    Infection with the food-borne trematodiasis, liver fluke Opisthorchis viverrini, is a major public health concern in Southeast Asia. While epidemiology and parasitic incidence in humans are well studied, ecological information on the O. viverrini intermediate hosts remains limited. This study aimed to investigate the factors affecting the distribution and abundance of the first intermediate host, Bithynia siamensis goniomphalos snails. Water quality and snails were sampled in 31 sites in Muang District, Khon Kaen Province, Thailand from June 2012 to January 2013 to characterize the B.s. goniomphalos snail habitats. Species relative abundance and Shannon's diversity and evenness indices were employed to describe snail compositions and diversities across different habitat types. Statistical analyses were conducted to examine the extent to which the water quality variables and species interactions account for the relative abundance of B.s. goniomphalos snails. The results showed that the freshwater habitats of ponds, streams and rice paddies possessed significantly different abiotic water qualities, with water temperature and pH showing distinct statistical differences (P<0.05). Different habitats had different snail diversity and species evenness, with high B.s. goniomphalos snail abundance at rice paddy habitats. The differences in snail abundance might be due to the distinct sets of abiotic water qualities associated with each habitat types. The relative abundance of B.s. goniomphalos snails was found to be negatively correlated with that of Filopaludina martensi martensi snails (r=-0.46, P<0.05), underscoring the possible influence of species interaction on B.s. goniomphalos snail population. Field work observations revealed that rice planting seasons and irrigation could regulate snail population dynamics at rice paddy habitats. This study provides new ecological insights into the factors affecting Bithynia snail distribution and abundance. It bridges the knowledge gap in O. viverrini disease ecology and highlights the potential effect of anthropogenic irrigation practices on B.s. goniomphalos snail ecology. PMID:24561073

  2. Trematode infections in freshwater snails and cattle from the Kafue wetlands of Zambia during a period of highest cattle-water contact.

    PubMed

    Phiri, A M; Phiri, I K; Chota, A; Monrad, J

    2007-03-01

    A total of 984 snails, comprising nine species, were collected from six areas in the Kafue wetlands between August and October 2003 to assess larval trematode infections. Of these, 135 (13.7%) were positive. Most trematode infections were recorded from Lymnaea natalensis (42.8%), which harboured four of the five morphologically different cercariae found. No trematodes were recovered from Bellamya capillata, Biomphalaria pfeifferi, Melanoides tuberculata, Physa acuta and Cleopatra nswendweensis. One snail (0.2%) of 416 Bulinus snails shed brevifurcate-apharyngeate distome cercariae while three (0.7%) shed amphistomes. Gymnocephalous and longifurcate-pharyngeate distome were the commonest types of cercariae recorded while xiphidiocercaria was the least common. The highest prevalence rates of F. gigantica (68.8%) and amphistomes (50.0%) in cattle (n = 101) were in Chiyasa while those in Kaleya had the lowest (9.1 and 18.2%, respectively). In most habitats, infections were recorded in both cattle and snails. Critical determinants of infection may have been the distance of settlements and/or cattle kraals, the number of animals in nearby homesteads and the presence of susceptible host snails. This study suggests that fascioliasis and amphistomiasis could be major constraints of cattle production in the Kafue wetlands because favourable factors were available to introduce and maintain the infections. It further provides a starting point for some comprehensive studies on snail-related aspects of transmission and snail host ecology in Zambia. PMID:17381873

  3. Relationship between Snail Population Density and Infection Status of Snails and Fish with Zoonotic Trematodes in Vietnamese Carp Nurseries

    PubMed Central

    Clausen, Jesper Hedegaard; Madsen, Henry; Murrell, K. Darwin; Phan Thi, Van; Nguyen Manh, Hung; Viet, Khue Nguyen; Dalsgaard, Anders

    2012-01-01

    Background Fish-borne zoonotic trematodes (FZT) are a food safety and health concern in Vietnam. Humans and other final hosts acquire these parasites from eating raw or under-cooked fish with FZT metacercariae. Fish raised in ponds are exposed to cercariae shed by snail hosts that are common in fish farm ponds. Previous risk assessment on FZT transmission in the Red River Delta of Vietnam identified carp nursery ponds as major sites of transmission. In this study, we analyzed the association between snail population density and heterophyid trematode infection in snails with the rate of FZT transmission to juvenile fish raised in carp nurseries. Methodology/Principal Findings Snail population density and prevalence of trematode (Heterophyidae) infections were determined in 48 carp nurseries producing Rohu juveniles, (Labeo rohita) in the Red River Delta area. Fish samples were examined at 3, 6 and 9 weeks after the juvenile fish were introduced into the ponds. There was a significant positive correlation between prevalence of FZT metacercariae in juvenile fish and density of infected snails. Thus, the odds of infection in juvenile fish were 4.36 and 11.32 times higher for ponds with medium and high density of snails, respectively, compared to ponds where no infected snails were found. Further, the intensity of fish FZT infections increased with the density of infected snails. Interestingly, however, some ponds with no or few infected snails were collected also had high prevalence and intensity of FZT in juvenile fish. This may be due to immigration of cercariae into the pond from external water sources. Conclusions/Significance The total number and density of potential host snails and density of host snails infected with heterophyid trematodes in the aquaculture pond is a useful predictor for infections in juvenile fish, although infection levels in juvenile fish can occur despite low density or absence infected snails. This suggests that intervention programs to control FZT infection of fish should include not only intra-pond snail control, but also include water sources of allochthonous cercariae, i.e. canals supplying water to ponds as well as snail habitats outside the pond such as rice fields and surrounding ponds. PMID:23285303

  4. Aquatic Snails, Passive Hosts of Mycobacterium ulcerans

    PubMed Central

    Marsollier, Laurent; Sévérin, Tchibozo; Aubry, Jacques; Merritt, Richard W.; Saint André, Jean-Paul; Legras, Pierre; Manceau, Anne-Lise; Chauty, Annick; Carbonnelle, Bernard; Cole, Stewart T.

    2004-01-01

    Accumulative indirect evidence of the epidemiology of Mycobacterium ulcerans infections causing chronic skin ulcers (i.e., Buruli ulcer disease) suggests that the development of this pathogen and its transmission to humans are related predominantly to aquatic environments. We report that snails could transitorily harbor M. ulcerans without offering favorable conditions for its growth and replication. A novel intermediate link in the transmission chain of M. ulcerans becomes likely with predator aquatic insects in addition to phytophage insects. Water bugs, such as Naucoris cimicoides, a potential vector of M. ulcerans, were shown to be infected specifically by this bacterium after feeding on snails experimentally exposed to M. ulcerans. PMID:15466578

  5. JUVENILE SNAILS, ADULT APPETITES: CONTRASTING RESOURCE CONSUMPTION BETWEEN TWO SPECIES OF APPLESNAILS

    E-print Network

    Burks, Romi

    crassipes (water hyacinth). In addition, we added chemical extracts to reconstituted watermilfoil and water reconstituted resources. All snails, regardless of life-history stage, avoided water hyacinth in either form. Chemical extracts from both water hyacinth and watermilfoil deterred consumption by all snails. When

  6. Direct Measurement of Ground Water Contaminant Discharge to Surface Water

    Microsoft Academic Search

    James R. Lundy; Mark Ferrey

    Defining zones of strongly discharging ground water is one way to characterize threats posed to surface water quality by contaminated ground water in both point source and non-point source settings. The three techniques most useful techniques for mapping areas of upward-discharging ground water and downward-discharging surface water are: temperature contrast, vertical gradient, and seepage flux. Pore water samples collected in

  7. Surface Water Development in Texas. 

    E-print Network

    McNeely, John G.; Lacewell, Ronald D.

    1977-01-01

    Engineers, orderly development of water rights became possible. This was the first State agency concerned with water development and water rights. Following severe floods in 1913 and 1914, there was agitation for an adopted in 1917. It stated... .................................. 14 Counties and Cities ............................... 14 Water Districts .................................... 14 State Water Agencies ................................. 15 Board of Water Engineers ......................... 15 Water Rights...

  8. Diffusion of water submonolayers on hydrophilic surfaces.

    PubMed

    Park, Jae Hyun; Aluru, N R

    2008-12-22

    In this letter, we investigate using molecular dynamics simulations the diffusion of water submonolayers on hydrophilic surfaces. In contrast to a strong hydrophilic Ag surface, on a weak hydrophilic Pb surface, the diffusion coefficient is remarkably enhanced at a critical surface coverage and a Lambda-shape anomaly with surface coverage is observed, i.e., the diffusion coefficient increases with the increase in surface coverage until a critical surface coverage, beyond which the diffusion coefficient decreases. We explain the anomalous diffusion of water on hydrophilic surfaces by a detailed understanding of molecular cavities and monolayer tail contributing to three-dimensional hydrogen bonding. PMID:19529784

  9. Slippage of water over hydrophobic surfaces

    Microsoft Academic Search

    Olga I. Vinogradova

    1999-01-01

    When water is confined between hydrophobic surfaces, its flow properties are significantly different from those in bulk, or between hydrophilic surfaces. These changes (that are usually ignored) may be interpreted in terms of hydrophobic slippage. This chapter reviews recent developments in the hydrodynamics of water confined between solid hydrophobic surfaces, emphasizing the main experimental facts, theoretical models suggested, and different

  10. Ground water and surface water; a single resource

    USGS Publications Warehouse

    Winter, Thomas C.; Harvey, Judson W.; Franke, O. Lehn; Alley, William M.

    1998-01-01

    The importance of considering ground water and surface water as a single resource has become increasingly evident. Issues related to water supply, water quality, and degradation of aquatic environments are reported on frequently. The interaction of ground water and surface water has been shown to be a significant concern in many of these issues. Contaminated aquifers that discharge to streams can result in long-term contamination of surface water; conversely, streams can be a major source of contamination to aquifers. Surface water commonly is hydraulically connected to ground water, but the interactions are difficult to observe and measure. The purpose of this report is to present our current understanding of these processes and activities as well as limitations in our knowledge and ability to characterize them.

  11. Lichen endozoochory by snails.

    PubMed

    Boch, Steffen; Prati, Daniel; Werth, Silke; Rüetschi, Jörg; Fischer, Markus

    2011-01-01

    Endozoochory plays a prominent role for the dispersal of seed plants. However, for most other plant taxa it is not known whether this mode of dispersal occurs at all. Among those other taxa, lichens as symbiotic associations of algae and fungi are peculiar as their successful dispersal requires movement of propagules that leaves the symbiosis functional. However, the potential for endozoochorous dispersal of lichen fragments has been completely overlooked. We fed sterile thalli of two foliose lichen species (Lobaria pulmonaria and Physcia adscendens) differing in habitat and air-quality requirements to nine snail species common in temperate Europe. We demonstrated morphologically that L. pulmonaria regenerated from 29.0% of all 379 fecal pellets, whereas P. adscendens regenerated from 40.9% of all 433 fecal pellets, showing that lichen fragments survived gut passage of all snail species. Moreover, molecular analysis of regenerated lichens confirmed the species identity for a subset of samples. Regeneration rates were higher for the generalist lichen species P. adscendens than for the specialist lichen species L. pulmonaria. Furthermore, lichen regeneration rates varied among snail species with higher rates after gut passage of heavier snail species. We suggest that gastropods generally grazing on lichen communities are important, but so far completely overlooked, as vectors for lichen dispersal. This opens new ecological perspectives and questions the traditional view of an entirely antagonistic relationship between gastropods and lichens. PMID:21533256

  12. Small Snails, Enormous Elephants

    NSDL National Science Digital Library

    Chicago Children's Museum

    2011-01-01

    This activity (located on page 2 of PDF) introduces learners to the real size of animals using nonstandard measurement. Learners use Unifix cubes and yarn lengths to measure a variety of animals (photos), from the very small like a snail to the very large like an elephant. As an extension, learners can use the cubes to create a bar graph depicting the animals' lengths.

  13. Mutagens in surface waters: a review

    Microsoft Academic Search

    Takeshi Ohe; Tetsushi Watanabe; Keiji Wakabayashi

    2004-01-01

    A review of the literature on the mutagenicity\\/genotoxicity of surface waters is presented in this article. Subheadings of this article include a description of sample concentration methods, mutagenic\\/genotoxic bioassay data, and suspected or identified mutagens in surface waters published in the literature since 1990. Much of the published surface water mutagenicity\\/genotoxicity studies employed the Salmonella\\/mutagenicity test with strains TA98 and\\/or

  14. Inquiry, Land Snails, and Environmental Factors.

    ERIC Educational Resources Information Center

    Barrow, Lloyd H.; Krantz, Patrick D.

    2002-01-01

    Introduces land snails for use in inquiry-based science activities. Describes common characteristics and safety considerations while introducing students to land snails. Explains procedures for inquiry-based use of land snails in classrooms. (YDS)

  15. Use of Bayluscide (Bayer 73) for Snail Control in Fish Ponds

    Microsoft Academic Search

    Ruth Francis-Floyd; James Gildea; Peggy Reed; Ruthellen Klinger

    1997-01-01

    Bayluscide applied to ponds on two commercial fish farms at five rates (from L1 to 13.5 kilogram per surface hectare) effectively controlled aquatic snails. Laboratory toxicity tests confirmed susceptibility of three endemic species of aquatic snail—Melanoides tuberculatus, Physella hendersoni, and Planorbella duryi—to Bayluscide. Observed 24-h concentrations lethal to 50% of snails (LC50) ranged from 0.062 to 0.085 mg\\/L, and 24-h

  16. Surface-Water Data for the Nation

    NSDL National Science Digital Library

    USGS

    This USGS site presents surface-water data. It includes detailed information from a number of sites around the nation. Real-time, recent, and streamflow data is included, as well as field measurements and a tutorial explaining how to perform a surface water retrieval and understand the results.

  17. 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.

  18. Variation of snail's abundance in two water bodies harboring strains of Pseudosuccinea columella resistant and susceptible to Fasciola hepatica miracidial infection, in Pinar del Río Province, Cuba.

    PubMed

    Gutiérrez, Alfredo; Hernandez, Dagmar F; Sánchez, Jorge

    2005-11-01

    The abundance of freshwater snails in two rural sites of Pinar del Río, Cuba, which harbor Pseudosuccinea columella susceptible and resistant to miracidia of Fasciola hepatica was followed for one year. Susceptible snails were found in the most anthropic site (IPA) whereas the resistant population inhabited the most preserved one (El Azufre). Only two snail species coexisted with P. columella at IPA site (Physa cubensis and Tarebia granifera) while five species were found at El Azufre, including an endemic from that province (Hemisinus cubanianus). Populations of both resistant and susceptible snails showed stable densities throughout the year, although the susceptible strain attained higher abundance. The highest densities were observed in April-May 2004 for the susceptible population whereas the resistant strain attained its highest abundance in January 2004. No record of Fossaria cubensis was made and the thiarid T. granifera occurred only at low densities. One of the sampled sites (IPA) meets all the conditions for the first report of P. columella naturally infected with larvae of F. hepatica. PMID:16410958

  19. Larval stages of digenetic trematodes in Melanopsis praemorsa snails from freshwater bodies in Palestine

    PubMed Central

    Bdir, Sami; Adwan, Ghaleb

    2011-01-01

    Objective To detect the species of larval trematodes (cercariae) in Melanopsis praemorsa snails from 5 different fresh water bodies in Palestine. Methods A total of 1 880 Melanopsis praemorsa snails were collected from different fresh water bodies in Palestine from October, 2008 to November, 2010. Cercariae in Melanopsis praemorsa snails were obtained by lighting and crushing methods. The behavior of cercariae was observed using a dissecting microscope. Results Three different species of larval trematodes were identified from Melanopsis praemorsa snails collected only from Al-Bathan fresh water body, while snails from other water bodies were not infected. These species were microcercous cercaria, xiphidiocercaria and brevifurcate lophocercous cercaria. These cercariae called Cercaria melanopsi palestinia I, Cercaria melanopsi palestinia II and Cercaria melanopsi palestinia III have not been described before from this snail in Palestine. The infection rate of Melanopsis praemorsa collected from Al-Bathan fresh water body was 5.7%, while the overall infection rate of snails collected from all fresh water bodies was 4.3%. Details are presented on the morphology and behavior of the cercariae as well as their development within the snail. Conclusions These results have been recorded for the first time and these cercariae may be of medical and veterinary importance. PMID:23569759

  20. Gray solitons on the surface of water.

    PubMed

    Chabchoub, A; Kimmoun, O; Branger, H; Kharif, C; Hoffmann, N; Onorato, M; Akhmediev, N

    2014-01-01

    The dynamics of surface gravity water waves can be described by the self-defocusing nonlinear Schrödinger equation. Recent observations of black solitons on the surface of water confirmed its validity for finite, below critical depth. The black soliton is a limiting case of a family of gray soliton solutions with finite amplitude depressions. Here, we report observations of gray solitons in water waves, thus, complementing our previous observations of black solitons. PMID:24580162

  1. Pesticide mitigation strategies for surface water quality

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  2. Slippage of Water over Nonwettable Surfaces

    Microsoft Academic Search

    Erhard Schnell

    1956-01-01

    When water flows over glass which has been treated with the vapor of dimethyldichlorosilane and thus made water repellent, slipping on the boundary between the solid surface and the water takes place. This is is shown in capillary tubes of various diameters. The amount of slipping is small, but measurable. It disappears or becomes extremely small in case of turbulent

  3. Adhesion under water: surface energy considerations

    Microsoft Academic Search

    John H. Clint; Amanda C. Wicks

    2001-01-01

    Contact angles for a set of probe liquids on solid surfaces have been used to determine the components of the solid surface energies. By the use of suitable combining rules, such data have then been used to calculate the work of adhesion of oil onto various solid surfaces under water. A surprising outcome of such studies is that the order

  4. The use of cold water to kill the exotic snail, red-rim melania Melanoides tuberculatus, a vector of the fish gill trematode Centrocestus formosanus, caught in dip nets and small seines

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A non-indigenous tropical snail, the red-rim melania Melanoides tuberculatus, has become established and is spreading in the United States. This parthenogenic snail can brood young internally, has the potential to displace native snail populations, and can transmit trematodes directly to fish and i...

  5. Camouflaged or tanned: plasticity in freshwater snail pigmentation

    PubMed Central

    Ahlgren, Johan; Yang, Xi; Hansson, Lars-Anders; Brönmark, Christer

    2013-01-01

    By having phenotypically plastic traits, many organisms optimize their fitness in response to fluctuating threats. Freshwater snails with translucent shells, e.g. snails from the Radix genus, differ considerably in their mantle pigmentation patterns, with snails from the same water body ranging from being completely dark pigmented to having only a few dark patterns. These pigmentation differences have previously been suggested to be genetically fixed, but we propose that this polymorphism is owing to phenotypic plasticity in response to a fluctuating environment. Hence, we here aimed to assess whether common stressors, including ultraviolet radiation (UVR) and predation, induce a plastic response in mantle pigmentation patterns of Radix balthica. We show, in contrast to previous studies, that snails are plastic in their expression of mantle pigmentation in response to changes in UVR and predator threats, i.e. differences among populations are not genetically fixed. When exposed to cues from visually hunting fish, R. balthica increased the proportion of their dark pigmentation, suggesting a crypsis strategy. Snails increased their pigmentation even further in response to UVR, but this also led to a reduction in pattern complexity. Furthermore, when exposed to UVR and fish simultaneously, snails responded in the same way as in the UVR treatment, suggesting a trade-off between photoprotection and crypsis. PMID:24046875

  6. Modelling global fresh surface water temperature

    Microsoft Academic Search

    L. P. H. van Beek; T. Eikelboom; M. T. H. van Vliet; M. F. P. Bierkens

    2011-01-01

    Temperature directly determines a range of water physical properties including vapour pressure, surface tension,\\u000adensity and viscosity, and the solubility of oxygen and other gases. Indirectly water temperature acts as a strong\\u000acontrol on fresh water biogeochemistry, influencing sediment concentration and transport, water quality parameters\\u000a(e.g. pH, nitrogen, phosphor, dissolved oxygen), chemical reaction rates, phytoplankton and zooplankton\\u000acomposition and the

  7. Surface Water Treatment Workshop Manual.

    ERIC Educational Resources Information Center

    Ontario Ministry of the Environment, Toronto.

    This manual was developed for use at workshops designed to increase the knowledge of experienced water treatment plant operators. Each of the fourteen lessons in this document has clearly stated behavioral objectives to tell the trainee what he should know or do after completing that topic. Areas covered in this manual include: basic water

  8. 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

  9. A molecular phylogeography approach to biological invasions of the New World by parthenogenetic Thiarid snails

    Microsoft Academic Search

    B. FACON; J.-P. POINTIER; M. GLAUBRECHT; C. POUX; P. JARNE; P. DAVID

    2003-01-01

    The parthenogenetic snail Melanoides tuberculata , present in tropical fresh waters of most of the Old World before 1950, has now invaded the Neotropical area. The phylogeography of this snail was studied to evaluate the pathways and number of such invasions. Because of parthenogenetic reproduction, individuals are structured into genetical clones. Within populations from both the original and invaded areas,

  10. CONTROLLING THE SPREAD OF NEW ZEALAND MUD SNAILS ON WADING GEAR

    Microsoft Academic Search

    Robert C. Hosea; Brian Finlayson

    SUMMARY New Zealand mud snails were first reported in Europe during the 1800s and in North America (Idaho) in 1987. Mud snails quickly colonize habitable waters, and they were first discovered in the Owens River in Eastern California in late 1999 and have since spread to the Mokelumne, Calaveras, and Napa rivers, as well as Rush, Hot and Putah creeks.

  11. Herbivory on aquatic vascular plants by the introduced golden apple snail ( Pomacea canaliculata ) in Lao PDR

    Microsoft Academic Search

    Nils O. L. Carlsson; Jean O. Lacoursière

    2005-01-01

    The effect of naturally found densities of the exotic and herbivorous golden apple snail (Pomacea canaliculata) on three dominant aquatic plants – duckweed (Lemna minor), water hyacinth (Eichhornia crassipes) and morning glory (Ipomoea aquatica) – was assessed in a wetland survey and quantified in a field experiment in Laos in southeast Asia. Snail grazing reduced plant biomass, but plant species

  12. Evidence for water structuring forces between surfaces

    SciTech Connect

    Stanley, Christopher B [ORNL; Rau, Dr. Donald [National Institutes of Health

    2011-01-01

    Structured water on apposing surfaces can generate significant energies due to reorganization and displacement as the surfaces encounter each other. Force measurements on a multitude of biological structures using the osmotic stress technique have elucidated commonalities that point toward an underlying hydration force. In this review, the forces of two contrasting systems are considered in detail: highly charged DNA and nonpolar, uncharged hydroxypropyl cellulose. Conditions for both net repulsion and attraction, along with the measured exclusion of chemically different solutes from these macromolecular surfaces, are explored and demonstrate features consistent with a hydration force origin. Specifically, the observed interaction forces can be reduced to the effects of perturbing structured surface water.

  13. IDENTIFYING VULNERABLE SURFACE WATER UTILITIES

    EPA Science Inventory

    This study was conducted to provide a mechanism and framework with which utility managers could analyze the effects of upstream discharges on source waters. Specific components of the project included selection, implementation, and demonstration of a microcomputer-based commerci...

  14. Use of a saponin based molluscicide to control Pomacea canaliculata snails in Southern Brazil.

    PubMed

    San Martíns, R; Gelmi, Claudio; de Oliveira, Jaime Vargas; Galo, José Luis; Pranto, Honorio

    2009-10-01

    Pomacea canaliculata snails pose a severe problem to direct seeded rice cultivated in Southern Brazil. Control of this snail is nowadays performed with toxic chemicals such as copper sulfate and fungicides such as fentin. A novel natural molluscicide based on alkali modified quinoa (Chenopodium quinoa) saponins was tested under laboratory conditions. Snails were collected in rice fields close to Porto Alegre (State of Rio Grande do Sul) and in Brusque (State of Santa Catarina, 400 km north of Porto Alegre). In Santa Catarina the product was very effective, while in Porto Alegre it had no effect. This unexpected behavior was probably due to the respiratory habits of the snails under different contents of dissolved oxygen in the water. Near Porto Alegre the water used in rice fields is heavily polluted, with dissolved oxygen levels of 1-2 ppm, and the snails rely primarily on their siphon and lungs to breathe. Since saponin control is probably due to an interaction between saponins with the sterols present in the cell walls in the gills, no control was observed. By contrast, in Santa Catarina the dissolved oxygen level of the water is 5-6 ppm, and the snails remain mostly underwater, breathing with their gills. In this case the snails died within 24 h at a dose of 20 and 30 ppm of product. To test this observation, snails grown in polluted waters were forced to remain underwater in saponin solutions and water (control) preventing the use of their siphon to breathe. The snails exposed to saponin solutions died, while the control snails survived, indicating that they were still able to use their gills to breathe. These results indicate that the use of the saponin product is limited to rice fields not irrigated with heavily polluted waters. PMID:19911565

  15. SURFACE WATER INTAKES, NEUSE RIVER WATERSHED, NC

    EPA Science Inventory

    The North Carolina Department of Environment, Health, and Natural Resources, Division of Water Quality, in cooperation with the NC Center for Geographic Information and Analysis, developed the Surface Water Intakes digital data to enhance planning, siting and impact analysis in a...

  16. Physicochemical properties of concentrated Martian surface waters

    E-print Network

    Physicochemical properties of concentrated Martian surface waters Nicholas J. Tosca,1 Scott M. Mc mineral deposits in the Valles Marineris region, and the possible role of saline waters in forming recent geomorphologic features all underscore the need to understand the physical properties of highly concentrated

  17. USGS Surface Water Information Pages

    NSDL National Science Digital Library

    Office of Surface Water

    This website provides maps and streamflow data for all monitored streams in the US. Links to USGS fact sheets and reports, data sets, publications, facilities, programs and techniques are also included. The site is helpful for designing activities on flooding and water rights.

  18. Snails from heavy-metal polluted environments have reduced sensitivity to carbon dioxide-induced acidity.

    PubMed

    Lefcort, Hugh; Cleary, David A; Marble, Aaron M; Phillips, Morgan V; Stoddard, Timothy J; Tuthill, Lara M; Winslow, James R

    2015-01-01

    Anthropogenic atmospheric CO2 reacts with water to form carbonic acid (H2CO3) which increases water acidity. While marine acidification has received recent consideration, less attention has been paid to the effects of atmospheric carbon dioxide on freshwater systems-systems that often have low buffering potential. Since many aquatic systems are already impacted by pollutants such as heavy metals, we wondered about the added effect of rising atmospheric CO2 on freshwater organisms. We studied aquatic pulmonate snails (Physella columbiana) from both a heavy-metal polluted watershed and snails from a reference watershed that has not experienced mining pollution. We used gaseous CO2 to increase water acidity and we then measured changes in antipredatory behavior and also survival. We predicted a simple negative additive effect of low pH. We hypothesized that snails from metal-polluted environments would be physiologically stressed and impaired due to defense responses against heavy metals. Instead, snails from populations that acclimated or evolved in the presence of heavy metal mining pollution were more robust to acidic conditions than were snails from reference habitats. Snails from mining polluted sites seemed to be preadapted to a low pH environment. Their short-term survival in acidic conditions was better than snails from reference sites that lacked metal pollution. In fact, the 48 h survival of snails from polluted sites was so high that it did not significantly differ from the 24 h survival of snails from control sites. This suggests that the response of organisms to a world with rising anthropogenic carbon dioxide levels may be complex and difficult to predict. Snails had a weaker behavioral response to stressful stimuli if kept for 1 month at a pH that differed from their lake of origin. We found that snails raised at a pH of 5.5 had a weaker response (less of a decrease in activity) to concentrated heavy metals than did snails raised at their natal pH of 6.5. Furthermore, snails raised a pH of 5.5, 6.0, and 7.0 all had a weaker antipredatory response to an extract of crushed snail cells than did the pH 6.5 treatment snails. PMID:26090314

  19. Assessing Phosphorous Loss to Protect Surface Water 

    E-print Network

    Garcia, Raul

    2005-01-01

    to prioritize fields for phosphorus management. Agriculturalists are developing and operating programs that minimize phosphorus losses, thereby reducing the amount that enters regional waters. Phosphorous is a necessary element in the growth and nutrition... faster growth of algae and other aquatic plants. Phosphorus levels are directly related to excessive algae growth in most fresh waters. It is one of the principal causes of impaired surface water quality in Texas, as well as the United States...

  20. Evidence for water structuring forces between surfaces

    PubMed Central

    Stanley, Christopher

    2011-01-01

    Structured water on apposing surfaces can generate significant energies due to reorganization and displacement of water as the surfaces encounter each other. Force measurements on a multitude of biological structures using the osmotic stress technique have elucidated commonalities that point toward an underlying hydration force. In this review, the forces of two contrasting systems are considered in detail: highly charged DNA and nonpolar, uncharged hydroxypropyl cellulose. Conditions for both net repulsion and attraction, along with the measured exclusion of chemically different solutes from these macromolecular surfaces, are explored and demonstrate common features consistent with a hydration force origin. Specifically, the observed interaction forces can be reduced to the effects of perturbing structured surface water. PMID:22125414

  1. 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. PMID:24920838

  2. Coupled surface-water and ground-water model

    USGS Publications Warehouse

    Swain, Eric D.; Wexler, Eliezer J.

    1991-01-01

    In areas with dynamic and hydraulically well connected ground-water and surface-water systems, it is desirable that stream-aquifer interaction be simulated with models of equal sophistication and accuracy. Accordingly, a new, coupled ground-water and surface-water model was developed by combining the U.S. Geological Survey models MODFLOW and BRANCH. MODFLOW is the widely used modular three-dimensional, finite-difference, ground-water model and BRANCH is a one-dimensional numerical model commonly used to simulate flow in open-channel networks. Because time steps used in ground-water modeling commonly are much longer than those used in surface-water simulations, provision has been made for handling multiple BRANCH time steps within one MODFLOW time step. Verification testing of the coupled model was done using data from previous studies and by comparing results with output from a simpler four-point implicit open-channel flow model linked with MODFLOW.

  3. 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 to the National Water Inventory System Web (NWISWeb) Interface.

  4. Aquatic snails from mining sites have evolved to detect and avoid heavy metals.

    PubMed

    Lefcort, H; Abbott, D P; Cleary, D A; Howell, E; Keller, N C; Smith, M M

    2004-05-01

    Toxicants in polluted environments are often patchily distributed. Hence, rather than being passive absorbers of pollution, some organisms have evolved the ability to detect and avoid toxicants. We studied the avoidance behavior of Physella columbiana, an aquatic pulmonate snail, in a pond that has been polluted with heavy metals for more than 120 years. Populations of this snail are rare at reference sites and are only robust at heavy-metal-polluted sites. We hypothesized that the snails are able to persist because they have evolved the ability to minimize their exposure to metals by actively avoiding metals in their environment. Using a Y-maze flow tank, we tested the avoidance behavior of snails to heavy-metal-polluted sediments and single-metal solutions of cadmium, zinc, or lead. We also tested the avoidance behaviors of the snails' laboratory-reared offspring raised in nonpolluted conditions. In addition, we tested the avoidance behavior of a small population of snails from a reference pond. Although all the snails we tested were able to detect low concentrations of heavy metals, we found that snails from the polluted site were the most sensitive, that their offspring were somewhat less sensitive, and that snails from the reference site were the least sensitive. This suggests that the ability of polluted-site snails to avoid heavy metals is both genetic and environmental. The concentrations of metals avoided by the snails from the polluted site were below the levels found at hot spots within their natal pond. The snails may be able to persist at this site because they decrease their exposure by moving to less-polluted sections of the pond. One application of our findings is the use of aquatic snails and our Y-maze design as an inexpensive pollution detector. Environmental pollutants such as lead, zinc, and arsenic are a problem throughout the world. People in underdeveloped countries often lack sophisticated pollution detection devices. We have developed a behavioral assay of aquatic pollution that is easy to use, is extremely sensitive (detection below 10 ppb), and can be constructed for fewer than 100 US dollars. Pulmonate snails are widely distributed in tropical, subtropical, and temperate parts of the globe, and they are often common in polluted waters. For countries such as India and Bangladesh, which must test thousands of shallow wells for possible contamination with heavy metals, our assay would be a good initial test. Once snails detected metals, then those samples could be confirmed by spectrometers. We encourage scientists in underdeveloped nations to consider our assay as an option. PMID:15253045

  5. Proterometra macrostoma (Trematoda: Azygiidae): location of the redia and emergence path from the snail, Elimia semicarinata (Gastropoda: Pleuroceridae).

    PubMed

    Rosen, Ronald; Berg, Ericka; Dolan, Julianna; King, Bailey; Martin, Michon; Mehmeti, Franceska

    2013-08-01

    The objectives of this study were to describe (1) the osmotic environment and precise location of the Proterometra macrostoma redia in its snail intermediate host, (2) where retraction of the distome body into the cercarial tail occurs, and (3) the subsequent emergence path of the cercaria out of the snail. Snails, Elimia semicarinata , were collected from North Elkhorn Creek in Scott County, Kentucky and screened daily for patent infections. Live rediae were extracted from infected snails in either artificial pond water (APW) or artificial snail water (ASW) and monitored for changes in morphology and movement every hour over 5 hr at 22 C. Infected and control snails were simultaneously fixed and decalcified in Cal-Ex II, prepared for routine paraffin sectioning, and serial sections subsequently analyzed for rediae and cercariae location. Significantly (?(2) = 42.45; 1 df; P = 0.0001) more rediae showed movement in ASW than in APW after 5 hr, suggesting a host compartment separate from the mantle cavity. Histological sections clearly showed rediae developing in close association with the snail digestive tract, within the peri-intestinal sinus of the snail, and isolated from the mantle cavity by a mantle membrane. Retraction of the distome body into the cercarial tail follows the emergence of the cercaria from the redia. Cercariae then enter the mantle cavity and emerge into fresh water through a siphon-like structure formed by the mantle collar of the snail. PMID:23343411

  6. Pollution of surface water in Europe

    PubMed Central

    Key, A.

    1956-01-01

    This paper discusses pollution of surface water in 18 European countries. For each an account is given of its physical character, population, industries, and present condition of water supplies; the legal, administrative, and technical means of controlling pollution are then described, and an outline is given of current research on the difficulties peculiar to each country. A general discussion of various aspects common to the European problem of water pollution follows; standards of quality are suggested; some difficulties likely to arise in the near future are indicated, and international collaboration, primarily by the exchange of information, is recommended to check or forestall these trends. PMID:13374532

  7. A Numerical Investigation of Land Surface Water on Landfalling Hurricanes

    Microsoft Academic Search

    Weixing Shen; Isaac Ginis; Robert E. Tuleya

    2002-01-01

    Little is known about the effects of surface water over land on the decay of landfalling hurricanes. This study, using the National Oceanic and Atmospheric Administration Geophysical Fluid Dynamics Laboratory hurricane model, examines the surface temperature changes due to hurricane-land surface water interactions, and their effects on the surface heat fluxes, hurricane structure, and intensity. Different water depths and surface

  8. Evaporation over fresh and saline water surfaces

    NASA Astrophysics Data System (ADS)

    Abdelrady, Ahmed; Timmermans, Joris; Vekerdy, Zoltan

    2013-04-01

    Evaporation over large water bodies has a crucial role in the global hydrological cycle. Evaporation occurs whenever there is a vapor pressure deficit between a water surface and the atmosphere, and the available energy is sufficient. Salinity affects the density and latent heat of vaporization of the water body, which reflects on the evaporation rate. Different models have been developed to estimate the evaporation process over water surfaces using earth observation data. Most of these models are concerned with the atmospheric parameters. However these models do not take into account the influence of salinity on the evaporation rate; they do not consider the difference in the energy needed for vaporization. For this purpose an energy balance model is required. Several energy balance models that calculate daily evapotranspiration exist, such as the surface energy balance system (SEBS). They estimate the heat fluxes by integration of satellite data and hydro-meteorological field data. SEBS has the advantage that it can be applied over a large scale because it incorporates the physical state of the surface and the aerodynamic resistances in the daily evapotranspiration estimation. Nevertheless this model has not used over water surfaces. The goal of this research is to adapt SEBS to estimate the daily evaporation over fresh and saline water bodies. In particular, 1) water heat flux and roughness of momentum and heat transfer estimation need to be updated, 2) upscaling to daily evaporation needs to be investigated and finally 3) integration of the salinity factor to estimate the evaporation over saline water needs to be performed. Eddy covariance measurements over the Ijsselmeer Lake (The Netherlands) were used to estimate the roughness of momentum and heat transfer at respectively 0.0002 and 0.0001 m. Application of these values over Tana Lake (freshwater), in Ethiopia showed latent heat to be in a good agreement with the measurements, with RMSE of 35.5 Wm-2and rRMSE of 4.7 %. Afterwards the validity of salinity adapted model was tested over different study areas using ECMWF data. It was found that for the original SEBS model and salinity-adapted model over Great Salt Lake, the RMSE were 0.62 and 0.24 mm respectively and the rRMSE 19% and 24%. The evaporation reduction of the Great Salt Lake and the oceans are 27% and 1 %, respectively. In conclusion, SEBS model is adapted to calculate the daily evaporation over fresh water and salt water by integration the salinity factor in the model.

  9. Global modeling of fresh surface water temperature

    NASA Astrophysics Data System (ADS)

    Bierkens, M. F.; Eikelboom, T.; van Vliet, M. T.; Van Beek, L. P.

    2011-12-01

    Temperature determines a range of water physical properties, the solubility of oxygen and other gases and acts as a strong control on fresh water biogeochemistry, influencing chemical reaction rates, phytoplankton and zooplankton composition and the presence or absence of pathogens. Thus, in freshwater ecosystems the thermal regime affects the geographical distribution of aquatic species through their growth and metabolism, tolerance to parasites, diseases and pollution and life history. Compared to statistical approaches, physically-based models of surface water temperature have the advantage that they are robust in light of changes in flow regime, river morphology, radiation balance and upstream hydrology. Such models are therefore better suited for projecting the effects of global change on water temperature. Till now, physically-based models have only been applied to well-defined fresh water bodies of limited size (e.g., lakes or stream segments), where the numerous parameters can be measured or otherwise established, whereas attempts to model water temperature over larger scales has thus far been limited to regression type of models. Here, we present a first attempt to apply a physically-based model of global fresh surface water temperature. The model adds a surface water energy balance to river discharge modelled by the global hydrological model PCR-GLOBWB. In addition to advection of energy from direct precipitation, runoff and lateral exchange along the drainage network, energy is exchanged between the water body and the atmosphere by short and long-wave radiation and sensible and latent heat fluxes. Also included are ice-formation and its effect on heat storage and river hydraulics. We used the coupled surface water and energy balance model to simulate global fresh surface water temperature at daily time steps on a 0.5x0.5 degree grid for the period 1970-2000. Meteorological forcing was obtained from the CRU data set, downscaled to daily values with ECMWF ERA40 re-analysis data. We compared our simulation results with daily temperature data from rivers and lakes (USGS, limited to the USA) and compared mean monthly temperatures with those recorded in the GEMS data set. Results show that the model is able to capture well the mean monthly surface temperature for the majority of the GEMS stations both in time as well as in space, while the inter-annual variability as derived from the USGS data was captured reasonably well. Results are poorest for the arctic rivers, possibly because the timing of ice-breakup is predicted too late in the year due to the lack of including a mechanical break-up mechanism. The spatio-temporal variation of water temperature reveals large temperature differences between water and atmosphere for the higher latitudes, while considerable lateral transport of heat can be observed for rivers crossing hydroclimatic zones such as the Nile, the Mississippi and the large rivers flowing into the Arctic. Overall, our model results show great promise for future projection of global fresh surface water temperature under global change.

  10. Occurrence of Klebisiella pneumoniae in Surface Waters

    PubMed Central

    Knittel, M. D.

    1975-01-01

    The occurrence of Klebsiella pneumoniae in surface waters was not found to be ubiquitous. When it was isolated, Escherichia coli could also be found. The fecal coliform to fecal streptococci ratio suggest that its origin could be human animal, or mixed sources. PMID:1096815

  11. Occurrence of Klebisiella pneumoniae in surface waters.

    PubMed

    Knittel, M D

    1975-05-01

    The occurrence of Klebsiella pneumoniae in surface waters was not found to be ubiquitous. When it was isolated, Escherichia coli could also be found. The fecal coliform to fecal streptococci ratio suggest that its origin could be human, animal, or mixed sources. PMID:1096815

  12. Habitat preference of freshwater snails in relation to environmental factors and the presence of the competitor snail Melanoides tuberculatus (Müller, 1774).

    PubMed

    Giovanelli, Alexandre; da Silva, Cesar Luiz Pinto Ayres Coelho; Leal, Geórgia Borges Eccard; Baptista, Darcílio Fernandes

    2005-04-01

    Our objective is to evaluate the habitat preference of freshwater snails in relation to environmental factors and the presence of the competitor snail Melanoides tuberculatus. In the first phase, snails was collected at 12 sites. This sampling sites presented a degree of organic input. In the second phase 33 sampling sites were chosen, covering a variety of lotic and lentic environments. The snail species found at Guapimirim, state of Rio de Janeiro, displayed a marked habitat preference, specially in relation to the physical characteristics of each environment. Other limiting factors for snail distribution at the studied lotic environments were the water current velocity and the amount of organic matter, mainly to Physa marmorata, M. tuberculatus, and Biomphalaria tenagophila. The absence of interactions between M. tuberculatus and another snails could be associated to the distinct spatial distribution of those species and the instability of habitats. This later factor may favor the coexistence of M. tuberculatus with B. glabrata by reduction of population density. In areas of schistosomiasis transmission some habitat modification may add to the instability of the environment, which would make room for the coexistence of M. tuberculatus and Biomphalaria spp. In this way, some of the usual measures for the control of snail hosts would prevent the extinction of populations of Biomphalaria spp. by M. tuberculatus in particular habitats. PMID:16021304

  13. The Effect of Aquatic Plant Abundance on Shell Crushing Resistance in a Freshwater Snail

    PubMed Central

    Chaves-Campos, Johel; Coghill, Lyndon M.; García de León, Francisco J.; Johnson, Steven G.

    2012-01-01

    Most of the shell material in snails is composed of calcium carbonate but the organic shell matrix determines the properties of calcium carbonate crystals. It has been shown that the deposition of calcium carbonate is affected by the ingestion of organic compounds. We hypothesize that organic compounds not synthesized by the snails are important for shell strength and must be obtained from the diet. We tested this idea indirectly by evaluating whether the abundance of the organic matter that snails eat is related to the strength of their shells. We measured shell crushing resistance in the snail Mexipyrgus churinceanus and the abundance of the most common aquatic macrophyte, the water lily Nymphaea ampla, in ten bodies of water in the valley of Cuatro Ciénegas, Mexico. We used stable isotopes to test the assumption that these snails feed on water lily organic matter. We also measured other factors that can affect crushing resistance, such as the density of crushing predators, snail density, water pH, and the concentration of calcium and phosphorus in the water. The isotope analysis suggested that snails assimilate water lily organic matter that is metabolized by sediment bacteria. The variable that best explained the variation in crushing resistance found among sites was the local abundance of water lilies. We propose that the local amount of water lily organic matter provides organic compounds important in shell biomineralization, thus determining crushing resistance. Hence, we propose that a third trophic level could be important in the coevolution of snail defensive traits and predatory structures. PMID:22970206

  14. Silver speciation in wastewater effluent, surface waters, and pore waters

    SciTech Connect

    Adams, N.W.H.; Kramer, J.R.

    1999-12-01

    Silver, inorganic sulfide, and thiol compounds were measured in municipal wastewater effluent, receiving waters, and pore waters from an anoxic lake sediment in order to predict silver speciation in these systems. The authors found submicromolar concentrations of inorganic sulfide even in fully oxic surface water. This inorganic sulfide is likely to exist in the form of colloidal metal sulfides, which have been shown to be stable under oxidizing conditions for periods of several hours. Inorganic sulfide in both the wastewater effluent and receiving waters was found to be 200 to 300 times in excess of silver concentrations, whereas inorganic sulfide in pore waters was 1,000 to 15,000 times in excess of silver concentrations. With sulfide in excess of silver, the authors predict silver sulfide complexes to dominate silver speciation. Thiols were present at low nanomolar levels in pore waters but were not detectable in wastewater effluent or receiving waters. Thiols do not appear to be important to silver speciation in these freshwater systems. Partitioning of silver into particular, colloidal, and dissolved size fractions showed that a significant proportion of silver is in the colloidal and dissolved phases. Dissolved phase concentrations were relatively constant in the treatment plant effluent and receiving waters, suggesting that silver in the <10-kDa size fraction is strongly complexed by ligands that are not significantly affected by aggregation or sorption processes.

  15. Occurrence of a Snail Borne Disease, Cercarial Dermatitis (Swimmer Itch) in Doon Valley (Uttarakhand), India

    PubMed Central

    JAUHARI, Rakesh Kumar; NONGTHOMBAM, Pemola Devi

    2014-01-01

    Abstract Background ‘Cercarial dermatitis’ also known as swimmers itch (Skin allergies) is caused by a trematode parasite, Schistosoma which has two hosts - an invertebrate (snail) and a vertebrate (livestock, human being). Although the availability of both vector snails and pathogens at the selected site the Doon Valley in northern India has already been confirmed but there was a hazy picture of the disease, whether it is due to entrance of cercariae or due to wild variety of grass (Parthenium hysterophorus). The present study is an attempt to provide a way forward towards the vector snails and snail borne diseases in the study area. Methods Snail sampling and identification was done by applying standard methods / using Keys & Catalogues. Associated parasites and cercariometry in snails has been worked out by cercarial shedding. Human involvement at zo-onotic level has been performed in collaboration with Health centers and socio- economic aspect of inhabitants of study area. Results The snail diversity encountered 19 species including the vector species such as Indoplanorbis exustus, Gyraulus convexiusculus, Melanoides tuberculata and Lymnaea acuminata. The cercarial diversity comprised Furcocercous, Monostome, Amphistome and liver fluke / Xiphidiocercaria. During the study (2009–2010), 0.173% was found with cercarial dermatitis among human population in the selected area. The symptoms of disease recorded were red spots and swellings on effected parts of skin. Frequent visits of livestock to the water body and presence of vector snails provides a clue in completing the life cycle of the parasite of the family Schistosomatidae. Conclusion Cercarial dermatitis has been considered a potential risk at those places where warm blooded and snail’s hosts share a link with aquatic bodies with particular emphasis to temperature and time of year.

  16. Source Water Assessment for the Las Vegas Valley Surface Waters

    NASA Astrophysics Data System (ADS)

    Albuquerque, S. P.; Piechota, T. C.

    2003-12-01

    The 1996 amendment to the Safe Drinking Water Act of 1974 created the Source Water Assessment Program (SWAP) with an objective to evaluate potential sources of contamination to drinking water intakes. The development of a Source Water Assessment Plan for Las Vegas Valley surface water runoff into Lake Mead is important since it will guide future work on source water protection of the main source of water. The first step was the identification of the watershed boundary and source water protection area. Two protection zones were delineated. Zone A extends 500 ft around water bodies, and Zone B extends 3000 ft from the boundaries of Zone A. These Zones extend upstream to the limits of dry weather flows in the storm channels within the Las Vegas Valley. After the protection areas were identified, the potential sources of contamination in the protection area were inventoried. Field work was conducted to identify possible sources of contamination. A GIS coverage obtained from local data sources was used to identify the septic tank locations. Finally, the National Pollutant Discharge Elimination System (NPDES) Permits were obtained from the State of Nevada, and included in the inventory. After the inventory was completed, a level of risk was assigned to each potential contaminating activity (PCA). The contaminants of concern were grouped into five categories: volatile organic compounds (VOCs), synthetic organic compounds (SOCs), inorganic compounds (IOCs), microbiological, and radionuclides. The vulnerability of the water intake to each of the PCAs was assigned based on these five categories, and also on three other factors: the physical barrier effectiveness, the risk potential, and the time of travel. The vulnerability analysis shows that the PCAs with the highest vulnerability rating include septic systems, golf courses/parks, storm channels, gas stations, auto repair shops, construction, and the wastewater treatment plant discharges. Based on the current water quality data (prior to treatment), the proximity of Las Vegas Wash to the intake, and the results of the vulnerability analysis of potential contaminating activities, it is determined that the drinking water intake is at a Moderate level of risk for VOC, SOC, and microbiological contaminants. The drinking water intake is at a High level of risk for IOC contaminants. Vulnerability to radiological contamination is Moderate. Source water protection in the Las Vegas Valley is strongly encouraged because of the documented influence of the Las Vegas Wash on the quality of the water at the intake.

  17. Laser induced surface stress on water droplets.

    PubMed

    Wang, Neng; Lin, Zhifang; Ng, Jack

    2014-10-01

    Laser induced stress on spherical water droplets is studied. At mechanical equilibrium, the body stress vanishes therefore we consider only the surface stress. The surface stress on sub-wavelength droplets is slightly weaker along the light propagation direction. For larger droplets, due to their light focusing effect, the forward stress is significantly enhanced. For a particle roughly 3 micron in radius, when it is excited at whispering gallery mode with Q ? 10? by a 1 Watt Gaussian beam, the stress can be enhanced by two orders of magnitude, and can be comparable with the Laplace pressure. PMID:25321955

  18. Dining local: the microbial diet of a snail that grazes microbial communities is geographically structured.

    PubMed

    O'Rorke, Richard; Cobian, Gerald M; Holland, Brenden S; Price, Melissa R; Costello, Vincent; Amend, Anthony S

    2015-05-01

    Achatinella mustelina is a critically endangered tree snail that subsists entirely by grazing microbes from leaf surfaces of native trees. Little is known about the fundamental aspects of these microbe assemblages: not taxonomic composition, how this varies with host plant or location, nor whether snails selectively consume microbes. To address these questions, we collected 102 snail faecal samples as a proxy for diet, and 102 matched-leaf samples from four locations. We used Illumina amplicon sequencing to determine bacterial and fungal community composition. Microbial community structure was significantly distinct between snail faeces and leaf samples, but the same microbes occurred in both. We conclude that snails are not 'picky' eaters at the microbial level, but graze the surface of whatever plant they are on. In a second experiment, the gut was dissected from non-endangered native tree snails in the same family as Achatinella to confirm that faecal samples reflect gut contents. Over 60% of fungal reads were shared between faeces, gut and leaf samples. Overall, location, sample type (faeces or leaf) and host plant identity all significantly explained the community composition and variation among samples. Understanding the microbial ecology of microbes grazed by tree snails enables effective management when conservation requires captive breeding or field relocation. PMID:25285515

  19. Atmospheric radiation model for water surfaces

    NASA Technical Reports Server (NTRS)

    Turner, R. E.; Gaskill, D. W.; Lierzer, J. R.

    1982-01-01

    An atmospheric correction model was extended to account for various atmospheric radiation components in remotely sensed data. Components such as the atmospheric path radiance which results from singly scattered sky radiation specularly reflected by the water surface are considered. A component which is referred to as the virtual Sun path radiance, i.e. the singly scattered path radiance which results from the solar radiation which is specularly reflected by the water surface is also considered. These atmospheric radiation components are coded into a computer program for the analysis of multispectral remote sensor data over the Great Lakes of the United States. The user must know certain parameters, such as the visibility or spectral optical thickness of the atmosphere and the geometry of the sensor with respect to the Sun and the target elements under investigation.

  20. Surface of Miranda - Identification of water ice

    NASA Astrophysics Data System (ADS)

    Brown, R. H.; Clark, R. N.

    1984-05-01

    Near-infrared spectrophotometry at 5-percent resolution shows Miranda to have a water-ice surface. Estimates of Miranda's albedo made from the depth of its 2.0-micron absorption band suggest that its visual geometric albedo is likely to be between 10 and 70 percent which when combined with the satellite's visual magnitude, yields a diameter of 500 + or 225 km. There is some evidence that suggests the visual geometric albedo of Miranda may be greater than or equal to 0.3, which implies that its diameter may lie near the lower end of the estimated range. With these results all the Uranian satellites are now known to have water-ice surfaces.

  1. Studies of Mineral–Water Surfaces

    Microsoft Academic Search

    Nancy L. Ross; Elinor C. Spencer; Andrey A. Levchenko; Alexander I. Kolesnikov; David J. Wesolowski; David R. Cole; Eugene Mamontov; Lukas Vlcek

    2009-01-01

    In this chapter we discuss the application of inelastic and quasielastic neutron scattering to the elucidation of the structure,\\u000a energetics, and dynamics of water confined on the surfaces of mineral oxide nanoparticles. We begin by highlighting recent\\u000a advancements in this active field of research before providing a brief review of the theory underpinning inelastic neutron\\u000a scattering (INS) and quasielastic neutron

  2. Distribution and abundance of schistosomiasis and fascioliasis host snails along the Mara River in Kenya and Tanzania.

    PubMed

    Dida, Gabriel O; Gelder, Frank B; Anyona, Douglas N; Matano, Ally-Said; Abuom, Paul O; Adoka, Samson O; Ouma, Collins; Kanangire, Canisius K; Owuor, Phillip O; Ofulla, Ayub V O

    2014-01-01

    We purposively selected 39 sampling sites along the Mara River and its two perennial tributaries of Amala and Nyangores and sampled snails. In addition, water physicochemical parameters (temperature, turbidity, dissolved oxygen, conductivity, alkalinity, salinity and pH) were taken to establish their influence on the snail abundance and habitat preference. Out of the 39 sites sampled, 10 (25.6%) had snails. The snail species encountered included Biomphalaria pfeifferi Krauss - the intermediate host of Schistosoma mansoni Sambon, Bulinus africanus - the intermediate host of Schistosoma haematobium, and Lymnaea natalensis Krauss - the intermediate host of both Fasciola gigantica and F. hepatica Cobbold. Ceratophallus spp., a non-vector snail was also encountered. Most (61.0%) of the snails were encountered in streamside pools. Schistosomiasis-transmitting host snails, B. pfeifferi and B. africanus, were fewer than fascioliasis-transmitting Lymnaea species. All the four different snail species were found to be attached to different aquatic weeds, with B. pfeifferi accounting for over half (61.1%) of the snails attached to the sedge, followed by B. africanus and Lymnaea spp., accounting for 22.2 and 16.7%, respectively. Ceratophallus spp. were non-existent in sedge. The results from this preliminary study show that snails intermediate hosts of schistosomiasis and fascioliasis exists in different habitats, in few areas along the Mara River, though their densities are still low to have any noticeable impacts on disease transmission in case they are infected. The mere presence of the vector snails in these focal regions calls for their immediate control and institution of proper regulations, management, and education among the locals that can help curtail the spread of the snails and also schistosomiasis and fascioliasis within the Mara River basin. PMID:25405008

  3. Effects of washing produce contaminated with the snail and slug hosts of Angiostrongylus cantonensis with three common household solutions.

    PubMed

    Yeung, Norine W; Hayes, Kenneth A; Cowie, Robert H

    2013-06-01

    The emerging infectious disease angiostrongyliasis (rat lungworm disease) is caused by ingesting snails and slugs infected by the nematode Angiostrongylus cantonensis. The definitive hosts of A. cantonensis are rats and the obligatory intermediate hosts are slugs and snails. Many cases result from accidentally ingesting infected snails or slugs on produce (eg, lettuce). This study assessed three readily available household products as washing solutions for removing snails and slugs from produce (romaine lettuce) to lower the probability of accidentally ingesting them. The solutions were acetic acid (vinegar), sodium hypochlorite (bleach), and sodium chloride (domestic salt). Snail and slug species known to be intermediate hosts and that are common in the Hawaiian Islands were used in the experiments: the alien snail Succinea tenella, the alien semi-slug Parmarion martensi, and the alien slugs Veronicella cubensis and Deroceras laeve. None of the products was any more effective than washing and rinsing with tap water alone. Most snails and slugs were removed after treatment but some remained on the lettuce even after washing and rinsing the produce. Only washing, rinsing, and then rinsing each leaf individually resulted in complete removal of all snails and slugs. The study did not address removal of any remaining slime left by the snails and slugs, nor did it address killing of worms. PMID:23901391

  4. Assessing nitrogen pressures on European surface water

    NASA Astrophysics Data System (ADS)

    Grizzetti, B.; Bouraoui, F.; de Marsily, G.

    2008-12-01

    The European environmental legislation on water, in particular the 2000 Water Framework Directive, requires the evaluation of nutrient pressures and the assessment of mitigation measures at the river basin scale. Models have been identified as tools that can contribute to fulfill these requirements. The objective of this research was the implementation of a modeling approach (Geospatial Regression Equation for European Nutrient losses (GREEN)) to assess the actual nitrogen pressures on surface water quality at medium and large basin scale (European scale) using readily available data. In particular the aim was to estimate diffuse nitrogen emissions into surface waters, contributions by different sources (point and diffuse) to the nitrate load in rivers, and nitrogen retention in river systems. A comprehensive database including nutrient sources and physical watershed characteristics was built at the European scale. The modeling partially or entirely covered some of the larger and more populated European river basins, including the Danube, Rhine, Elbe, Weser, and Ems in Germany, the Seine and Rhone in France, and the Meuse basin shared by France and Belgium. The model calibration was satisfactory for all basins. The source contribution to the in-stream nitrogen load, together with the diffuse nitrogen emissions and river nitrogen retention were estimated and were found to be in the range of values reported in the literature. Finally, the model results were extrapolated to estimate the diffuse nitrogen emission and source apportionment at the European scale.

  5. Epidemiology of cercarial stage of trematodes in freshwater snails from Chiang Mai province, Thailand

    PubMed Central

    Chontananarth, Thapana; Wongsawad, Chalobol

    2013-01-01

    Objective To investigate the epidemiological situation of cercarial trematodes infection in freshwater snails from different water resources in Chiang Mai province, Thailand. Methods The snail specimens were collected from 13 districts of Chiang Mai province during April 2008 to February 2012. The prevalence of cercarial infection in snails was investigated using the crushing method. The drawing was done with the help of a camera lucida for the morphological study. Results A total of 2?479 snail individuals were collected and classified into 7 families, 11 genera, and 14 species, Among them, 8 snails species were found to be infected with an overall prevalence of 17.27% (428/2?479), which infected with nine groups of cercariae; gymnocephalous cercaria, strigea cercaria, megalurous cercaria, monostome cercaria, parapleurolophocercous cercaria (Haplorchis cercaria), pleurolophocercous cercaria, furcocercous cercaria (Transversotrema cercaria), xiphidiocercaria, and virgulate cercaria. The parapleurolophocercous cercaria was found to be the dominant type among the cercarial infection in the snails (64.25%). Conclusions The various species of snails found in the research location act as the intermediate hosts for the high prevalence of parasitic infection of many species of mammals. This work will provide new information on both the distribution and first intermediate host of trematodes. PMID:23620846

  6. The Application of Electric Shock as a Novel Pest Control Method for Apple Snail, Pomacea canaliculata (Gastropoda: Ampullariidae)

    NASA Astrophysics Data System (ADS)

    Yagyu, Yoshihito; Tsuji, Satoshi; Satoh, Saburoh; Yamabe, Chobei

    The apple snail, Pomacea canaliculata, brought to Japan from Taiwan for human consumption in the 1980s, has come to be considered as deleterious for rice cultivation. The snail is unable to injure young rice plants while receiving electric shock because the snail retracts its entire body into its shell and shuts its aperture with its operculum. Electric shock should be applied intermittently to reduce the amount of energy that is wasted when the snail is in its shell made of one of the insulator. The minimum electric shock required for controlling snails and the time required for movement after application of electric shock to determine the frequency of each electric shock were investigated using two methods; vertical and horizontal application of the electrical stimulation. The results showed that there is a strong correlation between the strength of electric shock and the reaction of the snails, and electric shock made snails inactive when it was applied 0.35 A/m2 in the horizontal direction and 0.45 A/m2 in the vertical direction with water of 11 mS/m. A positive correlation was also found between electric shock and the reaction of the snails and shell height. In comparison with larger snails, the smaller snails had higher threshold levels against electric current density because their shorter feet tended to have lower voltage dorp. Moreover, the frequency of electric shock should be chosen the minimum duration for the inactive condition, and it was approximately 10 seconds. Consequently the direction of electric current should be in the horizontal direction above 0.35 A/m2 and the frequency of electric shock should be less than 10 seconds for practical use. However, electric shock would have to be maintained at greater than 0.35 A/m2 because snails might become habituated to electric shock and water in paddy field would have high electric conductivity.

  7. Landscape approach to identifying environments where ground water and surface water are closely interrelated

    USGS Publications Warehouse

    Winter, Thomas C.

    1995-01-01

    Understanding the interaction of ground water and surface water is fundamental to solving many of the water resource problems facing the Nation. To facilitate efficient management of the Nation's water resources, a program of study and evaluation of the interaction of ground water and surface water is proposed that would emphasize intersite comparison between 24 environments throughout the Nation.

  8. Bacteriophages as surface and ground water tracers

    NASA Astrophysics Data System (ADS)

    Rossi, P.; Dörfliger, N.; Kennedy, K.; Müller, I.; Aragno, M.

    Bacteriophages are increasingly used as tracers for quantitative analysis in both hydrology and hydrogeology. The biological particles are neither toxic nor pathogenic for other living organisms as they penetrate only a specific bacterial host. They have many advantages over classical fluorescent tracers and offer the additional possibility of multi-point injection for tracer tests. Several years of research make them suitable for quantitative transport analysis and flow boundary delineation in both surface and ground waters, including karst, fractured and porous media aquifers. This article presents the effective application of bacteriophages based on their use in differing Swiss hydrological environments and compares their behaviour to conventional coloured dye or salt-type tracers. In surface water and karst aquifers, bacteriophages travel at about the same speed as the typically referenced fluorescent tracers (uranine, sulphurhodamine G extra). In aquifers of interstitial porosity, however, they appear to migrate more rapidly than fluorescent tracers, albeit with a significant reduction in their numbers within the porous media. This faster travel time implies that a modified rationale is needed for defining some ground water protection area boundaries. Further developments of other bacteriophages and their documentation as tracer methods should result in an accurate and efficient tracer tool that will be a proven alternative to conventional fluorescent dyes.

  9. REVIEW PAPER Modelling pesticides transfer to surface water

    E-print Network

    Paris-Sud XI, Université de

    REVIEW PAPER Modelling pesticides transfer to surface water at the catchment scale: a multi of mitigation measures on pesticide transfer to surface water. Here a literature review of 286 investigations and conceptual models are the most popular approaches to assess the transfer of pesticides to surface water

  10. Mobility of Water on Oxide Surfaces Studied by QENS

    Microsoft Academic Search

    Mamontov

    2007-01-01

    Although neutron scattering is often considered a bulk probe, we demonstrate that the mobility of surface water on oxide nano-powders can be investigated using quasielastic neutron scattering. We discuss how the reduced number of hydrogen bonds per water molecule associated with surface confinement leads to a qualitative modification of single-particle translational dynamics compared to bulk water. The mobility of surface

  11. 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 groundwater table observations, and with estimates of total water storage variations from the GRACE satellites mission. Due to the difficulty in estimating area-averaged seasonal groundwater storage variations from point observations of groundwater levels, it is uncertain whether WaterGAP underestimates actual variations or not. We conclude that WaterGAP possibly overestimates water withdrawals in the High Plains aquifer where impact of human water use on water storage is readily discernible based on WaterGAP calculations and groundwater observations. No final conclusion can be drawn regarding the possibility of monitoring water withdrawals in the High Plains aquifer using GRACE. For the less intensively irrigated Mississippi basin, observed and modeled seasonal groundwater storage reveals a discernible impact of water withdrawals in the basin, but this is not the case for total water storage such that water withdrawals at the scale of the whole Mississippi basin cannot be monitored by GRACE.

  12. Pumpkin Creek Surface-Ground Water by J. David Aiken

    E-print Network

    Nebraska-Lincoln, University of

    . Over 20 years ago, Pumpkin Creek was closed to the issuance of new surface water rights by the Nebraska water. This means that the priority rule of "first in time is first in right" would apply to bothPumpkin Creek Surface-Ground Water Dispute by J. David Aiken UNL Water and Agricultural Law

  13. Investigating surface waterwell interaction using stable isotope ratios of water*

    E-print Network

    wellshaveappreciablesurfacewatercontributionsandarepotentially vulnerable to contaminants in the surface water. When looking at wells with more than 6 sampling underlying the city and the river. Numerical ground- water-flow modeling (Hunt et al., 2003; Chapel et alInvestigating surface water­well interaction using stable isotope ratios of water* Randall J. Hunta

  14. Water rotation barriers on protein molecular surfaces

    NASA Astrophysics Data System (ADS)

    Tompa, K.; Bokor, M.; Verebélyi, T.; Tompa, P.

    2015-02-01

    The experimental characterization of hindered-rotation barriers and mapping the energetic heterogeneity of water molecules bound to the molecular "surface" of proteins is critical for understanding the functional interaction of proteins with their environment. Here, we show how to achieve this goal by an original wide-line NMR procedure, which is based on the spectral motional narrowing phenomenon following the melting (thawing) process of interfacial ice. The procedure highlights the differences between globular and intrinsically disordered proteins and it enables to delineate the effect of solvent on protein structure, making a distinction between point mutants, monomeric and oligomeric states, and characterizing the molecular interactions taking part in different cellular processes. We put this unique experimental approach introducing novel physical quantities and quantifying the heterogeneous distribution of motional activation energy of water in the interfacial landscape into a historical perspective, demonstrating its utility through a variety of globular and disordered proteins.

  15. Surface Crystallization of Supercooled Water in Clouds

    NASA Technical Reports Server (NTRS)

    Tabazadeh, Azadeh; Gore, Warren J. (Technical Monitor)

    2002-01-01

    The process by which liquid cloud droplets homogeneously crystallize into ice is still not well-understood. The ice nucleation process based on the standard and classical theory of homogeneous freezing, initiates within the interior volume of a cloud droplet. Current experimental data on homogeneous freezing rates of ice in droplets of supercooled water, both in air and emulsion oil samples, show considerable scatter. For example, at -33 C, the reported volume-based freezing rates of ice in supercooled water vary by as much as 5 orders of magnitude, which is well outside the range of measurement uncertainties. Here, we show that the process of ice nucleus formation at the air (or oil)-liquid water interface may help to explain why experimental results on ice nucleation rates yield different results in different ambient phases. Our results also suggest that surface crystallization of ice in cloud droplets can explain why low amounts of supercooled water have been observed in the atmosphere near -40 C.

  16. Surface crystallization of supercooled water in clouds

    PubMed Central

    Tabazadeh, A.; Djikaev, Y. S.; Reiss, H.

    2002-01-01

    The process by which liquid cloud droplets homogeneously crystallize into ice is still not well understood. The ice nucleation process based on the standard and classical theory of homogeneous freezing initiates within the interior volume of a cloud droplet. Current experimental data on homogeneous freezing rates of ice in droplets of supercooled water, both in air and emulsion oil samples, show considerable scatter. For example, at ?33°C, the reported volume-based freezing rates of ice in supercooled water vary by as many as 5 orders of magnitude, which is well outside the range of measurement uncertainties. Here, we show that the process of ice nucleus formation at the air (or oil)-liquid water interface may help to explain why experimental results on ice nucleation rates yield different results in different ambient phases. Our results also suggest that surface crystallization of ice in cloud droplets can explain why low amounts of supercooled water have been observed in the atmosphere near ?40°C. PMID:12456877

  17. On detecting surface and sub-surface bodies in water by virtue of their surface and water column wakes

    Microsoft Academic Search

    A. Benilov; B. Bunin; G. Dardiere; A. Sutin; D. Zeng; R. Martini

    2010-01-01

    This paper presents theoretical and experimental results of detection and parameterization of moving bodies and scuba divers based on their surface and water column signatures under Hudson River estuary conditions. (1) Theoretical and experimental (SIT DL Towing Tank) estimates of wake characteristics for bodies of interest are carried out. (2) The IR-images of ship wakes at the surface of the

  18. Induction of egg-laying in the pond snail Lymnaea stagnalis by environmental stimulation of the release of ovulation hormone from the Caudo—Dorsal Cells

    Microsoft Academic Search

    A. ter Maat; J. C. Lodder; M. Wilbrink

    1983-01-01

    Ovipository activity decreases when specimens of the pond snail, Lymnaea stagnalis, are kept in closed jars that are not cleaned regularly. When the snails are transferred from dirty to clean water, egg-laying occurs within 3 h in over 90% of the animals. The number of eggs per egg mass laid after water change is directly related to the length of

  19. Exposure routes of copper: Short term effects on survival, weight, and uptake in Florida apple snails ( Pomacea paludosa)

    Microsoft Academic Search

    Tham C. Hoang; Gary M. Rand

    2009-01-01

    The uptake and effects (survival, weight) of copper (Cu) on Florida apple snails (Pomacea paludosa) via exposures to copper-enriched agricultural soil–water and water-only treatments were investigated. Soils were collected from citrus sites in south Florida and flooded with laboratory freshwater for 14d. Neonate apple snails (?96-h-old) were then exposed to either Cu from a soil-overlying water (i.e., flooded agricultural soils)

  20. Metolachlor and atrazine fate in surface water systems

    SciTech Connect

    Rice, P.J.; Anderson, T.A.; Coats, J.R. [Iowa State Univ., Ames, IA (United States)

    1995-12-31

    The detection of pesticides in surface water and ground water provokes concern involving human health risks associated with pesticide exposure. Monitoring studies of surface waters have detected concentrations of herbicides that exceed the U.S. Environmental Protection Agency proposed maximum contamination level (MCL) for drinking water. Conventional water treatment processes do not remove many herbicides. Tap water drawn from surface-water sources has been reported to contain levels of herbicides above the regulatory limits. There is current interest in the use of artificial wetlands and macrophyte-cultured ponds in waste-water-treatment systems. Aquatic plant-based water treatment systems improve waste water effluent by solid filtration and nutrient assimilation. Various aquatic plants have been shown to accumulate metals, absorb inorganic ions, and accelerate the biodegradation of complex organics. Our research evaluates the fate of metolachlor and atrazine in surface water, surface water/sediment, and surface water/aquatic plant incubation systems to study the influence of sediment and aquatic plants in the removal and biotransformation of herbicides from contaminated waters. Aquatic macrophyte systems may prove to be useful in the remediation of herbicide contaminated surface waters in water treatment facilities or in the reduction of herbicide concentrations from tile drain effluents prior to entering watersheds.

  1. Moving Water Droplets on Aluminum and Copper Surfaces Using Surface Tension Gradients

    NASA Astrophysics Data System (ADS)

    Alheshibri, Muidh; Rogers, Nathaniel; Sommers, Andrew; Eid, Khalid

    2013-03-01

    The behavior of water droplets on metal surfaces is very important for many applications, especially in heat exchangers in air conditioning and refrigeration. We use photolithography and/or shadow masks to create alternating hydrophobic/hydrophilic Cu micro-channels on an aluminum surface and to move water droplets on the surface. The contact angle that is formed between water droplets and the surface is clearly asymmetrical due to the different surface properties at the contact line between the droplets and the patterned surface. An HDFT self-assembled mono-layer allows for a large change in the water droplet contact angle on the copper, but seems to have no effect on the aluminum surface. We will show our results on the effect of the surface patterning and surface roughness on water droplet behavior. We also demonstrate that the engineered surface gradients cause water droplets to travel more than 1'' on a horizontal or upward tilted surface.

  2. Water: one molecule, two surfaces, one mistake

    E-print Network

    Carlos Vega

    2015-05-29

    In order to rigorously evaluate the energy and dipole moment of a certain configuration of molecules one needs to solve the Schr\\"odinger equation. Repeating this for many different configurations allows one to determine the potential energy surface (PES) and the dipole moment surface (DMS). Since the early days of computer simulation it has been implicitly accepted that for empirical potentials the charges used to fit the PES should also be used to describe the DMS. This is a mistake. Partial charges are not observable magnitudes. They should be regarded as adjustable fitting parameters. Optimal values used to describe the PES are not necessarily the best to describe the DMS. One could use two fits: one for the PES, and another for the DMS. This is a common practice in the quantum chemistry community, but not used so often by the community performing computer simulations. This idea affects all types of modelling of water (with the exception of ab-initio calculations) from coarse grained to non-polarizable and polarizable models. We anticipate that an area that will benefit dramatically from having both, a good PES and a good DMS, is the modelling of water in the presence of electric fields.

  3. Enhancing Drinking Water Supply by Better Understanding Surface Water Ground Water Interaction

    E-print Network

    Rhode Island, University of

    for significant numbers of large macro-organisms, algae and surrogate indicators of surface water presence. Part.) significant occurrence of insects or other microorganisms, algae, organic debris, or large- diameter pathogens

  4. Grooved organogel surfaces towards anisotropic sliding of water droplets.

    PubMed

    Zhang, Pengchao; Liu, Hongliang; Meng, Jingxin; Yang, Gao; Liu, Xueli; Wang, Shutao; Jiang, Lei

    2014-05-21

    Periodic micro-grooved organogel surfaces can easily realize the anisotropic sliding of water droplets attributing to the formed slippery water/oil/solid interface. Different from the existing anisotropic surfaces, this novel surface provides a versatile candidate for the anisotropic sliding of water droplets and might present a promising way for the easy manipulation of liquid droplets for water collection, liquid-directional transportation, and microfluidics. PMID:24610716

  5. The Surface Water and Ocean Topography Mission: Observing Terrestrial Surface Water and Oceanic Submesoscale Eddies

    Microsoft Academic Search

    Michael Durand; Lee-Lueng Fu; Dennis P. Lettenmaier; Douglas E. Alsdorf; Ernesto Rodriguez; Daniel Esteban-Fernandez

    2010-01-01

    The elevation of the ocean surface has been measured for over two decades from spaceborne altimeters. However, existing altimeter measurements are not adequate to characterize the dynamic variations of most inland water bodies, nor of ocean eddies at scales of less than about 100 km, notwithstanding that such eddies play a key role in ocean circulation and climate change. For

  6. Impact of invasive apple snails on the functioning and services of natural and managed wetlands

    NASA Astrophysics Data System (ADS)

    Horgan, Finbarr G.; Stuart, Alexander M.; Kudavidanage, Enoka P.

    2014-01-01

    At least 14 species of apple snail (Ampullariidae) have been released to water bodies outside their native ranges; however, less than half of these species have become widespread or caused appreciable impacts. We review evidence for the impact of apple snails on natural and managed wetlands focusing on those studies that have elucidated impact mechanisms. Significant changes in wetland ecosystems have been noted in regions where the snails are established: Two species in particular (Pomacea canaliculata and Pomacea maculata) have become major pests of aquatic crops, including rice, and caused enormous increases in molluscicide use. Invasive apple snails have also altered macrophyte community structure in natural and managed wetlands through selective herbivory and certain apple snail species can potentially shift the balance of freshwater ecosystems from clear water (macrophyte dominated) to turbid (plankton dominated) states by depleting densities of native aquatic plants. Furthermore, the introductions of some apple snail species have altered benthic community structure either directly, through predation, or indirectly, through exploitation competition or as a result of management actions. To date much of the evidence for these impacts has been based on correlations, with few manipulative field or mesocosm experiments. Greater attention to impact monitoring is required, and, for Asia in particular, a landscape approach to impact management that includes both natural and managed-rice wetlands is recommended.

  7. Snail modulates cell metabolism in MDCK cells

    SciTech Connect

    Haraguchi, Misako, E-mail: haraguci@m3.kufm.kagoshima-u.ac.jp [Department of Biochemistry and Molecular Biology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-8544 (Japan)] [Department of Biochemistry and Molecular Biology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-8544 (Japan); Indo, Hiroko P. [Department of Maxillofacial Radiology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-8544 (Japan)] [Department of Maxillofacial Radiology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-8544 (Japan); Iwasaki, Yasumasa [Health Care Center, Kochi University, Kochi 780-8520 (Japan)] [Health Care Center, Kochi University, Kochi 780-8520 (Japan); Iwashita, Yoichiro [Department of Maxillofacial Radiology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-8544 (Japan)] [Department of Maxillofacial Radiology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-8544 (Japan); Fukushige, Tomoko [Department of Dermatology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-8544 (Japan)] [Department of Dermatology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-8544 (Japan); Majima, Hideyuki J. [Department of Maxillofacial Radiology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-8544 (Japan)] [Department of Maxillofacial Radiology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-8544 (Japan); Izumo, Kimiko; Horiuchi, Masahisa [Department of Environmental Medicine, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-8544 (Japan)] [Department of Environmental Medicine, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-8544 (Japan); Kanekura, Takuro [Department of Dermatology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-8544 (Japan)] [Department of Dermatology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-8544 (Japan); Furukawa, Tatsuhiko [Department of Molecular Oncology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-8544 (Japan)] [Department of Molecular Oncology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-8544 (Japan); Ozawa, Masayuki [Department of Biochemistry and Molecular Biology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-8544 (Japan)] [Department of Biochemistry and Molecular Biology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-8544 (Japan)

    2013-03-22

    Highlights: ? MDCK/snail cells were more sensitive to glucose deprivation than MDCK/neo cells. ? MDCK/snail cells had decreased oxidative phosphorylation, O{sub 2} consumption and ATP content. ? TCA cycle enzyme activity, but not expression, was lower in MDCK/snail cells. ? MDCK/snail cells showed reduced PDH activity and increased PDK1 expression. ? MDCK/snail cells showed reduced expression of GLS2 and ACLY. -- Abstract: Snail, a repressor of E-cadherin gene transcription, induces epithelial-to-mesenchymal transition and is involved in tumor progression. Snail also mediates resistance to cell death induced by serum depletion. By contrast, we observed that snail-expressing MDCK (MDCK/snail) cells undergo cell death at a higher rate than control (MDCK/neo) cells in low-glucose medium. Therefore, we investigated whether snail expression influences cell metabolism in MDCK cells. Although gylcolysis was not affected in MDCK/snail cells, they did exhibit reduced pyruvate dehydrogenase (PDH) activity, which controls pyruvate entry into the tricarboxylic acid (TCA) cycle. Indeed, the activity of multiple enzymes involved in the TCA cycle was decreased in MDCK/snail cells, including that of mitochondrial NADP{sup +}-dependent isocitrate dehydrogenase (IDH2), succinate dehydrogenase (SDH), and electron transport Complex II and Complex IV. Consequently, lower ATP content, lower oxygen consumption and increased survival under hypoxic conditions was also observed in MDCK/snail cells compared to MDCK/neo cells. In addition, the expression and promoter activity of pyruvate dehydrogenase kinase 1 (PDK1), which phosphorylates and inhibits the activity of PDH, was increased in MDCK/snail cells, while expression levels of glutaminase 2 (GLS2) and ATP-citrate lyase (ACLY), which are involved in glutaminolysis and fatty acid synthesis, were decreased in MDCK/snail cells. These results suggest that snail modulates cell metabolism by altering the expression and activity of key enzymes. This results in enhanced glucose dependency and leads to cell death under low-glucose conditions. On the other hand, the reduced requirements for oxygen and nutrients from the surrounding environment, might confer the resistance to cell death induced by hypoxia and malnutrition.

  8. The Organic Shell Matrix of the Freshwater Snail Biomphalaria glabrata

    Microsoft Academic Search

    Julia C Marxen; Wilhelm Becker

    1997-01-01

    The organic matrix of the aragonitic, cross-lamellar-structured shell of the freshwater snail Biomphalaria glabrata (Basommatophora, Pulmonata) has been investigated. The analysis of the water-soluble matrix components revealed protein as the main part of the matrix, followed by sulfate, neutral sugar, amino sugar, and small amounts of uronic acid and phosphate. In the amino acid analysis, glycine was the main amino

  9. Effect of Glyphosate on the Development of Pseudosuccinea columella Snails

    Microsoft Academic Search

    T. M. Tate; J. O. Spurlock; F. A. Christian

    1997-01-01

    .   Glyphosate (Roundup) is one of the most commonly used broad-spectrum herbicides with little to no hazard to animals, man,\\u000a or the environment. Due to its widespread use, there is continuous contamination of the environment in both soil and water\\u000a with this herbicide. There is a paucity of long-term exposure studies with sublethal concentrations of glyphosate on aquatic\\u000a snails. This

  10. Passive water control at the surface of a superhydrophobic lichen

    Microsoft Academic Search

    Christopher A. E. Hamlett; Neil James Shirtcliffe; F. Brian Pyatt; Michael I. Newton; Glen McHale; Kerstin Koch

    Some lichens have a super-hydrophobic upper surface, which repels water drops, keeping the surface dry but probably preventing\\u000a water uptake. Spore ejection requires water and is most efficient just after rainfall. This study was carried out to investigate\\u000a how super-hydrophobic lichens manage water uptake and repellence at their fruiting bodies, or podetia. Drops of water were\\u000a placed onto separate podetia

  11. A Surface Plasmon Resonance Investigation of How Water Meets a Hydrophobic Surface.

    NASA Astrophysics Data System (ADS)

    Poynor, Adele; Shemelya, Corey

    2009-03-01

    By definition hydrophobic substances hate water. Water placed on a hydrophobic surface will form a drop in order to minimize its contact area. What happens when water is forced into contact with a hydrophobic surface? One theory is that an ultra-thin low- density region forms near the surface. We have employed the surface-sensitive, quantum-optical technique of Surface Plasmon Resonance (SPR) to verify the existence of this region at the boundary.

  12. Snails, stable iostopes, and southwestern desert paleoclimates

    SciTech Connect

    Sharpe, S.E. [Univ. and Community College System of Nevada, Reno, NV (United States); Whelan, J.F.; Forester, R.M.; Burdett, J.

    1995-09-01

    Modern and fossil molluscs (snails) occur in many localities in and semi-arid regions throughout the desert southwest. Live terrestrial snails are found under rocks and in forest litter and aquatic taxa inhabit springs, seeps, and/or wetlands. Molluscs uptake local water during their growing season (spring and summer) and incorporate its delta 180 signature into their shells. Preliminary 180 analysis of modem shells from the southern Great Basin indicates that the shells probably reflect meteoric water 180 values during the growing season. This provides a way to estimate the delta 180 value of precipitation and, thereby, the source of the moisture-bearing air masses. Significant 180 variability in shells analyzed include geographic location, elevation, taxonomy, and habitat (terrestrial, spring, or wetland). We found a rough inverse correlation with elevation in modem shells from the Spring Range in southern Nevada. The delta 180 values of modem and fossil shells are also very different; modem values in this location are much higher than those from nearby late Pleistocene-age molluscs suggesting that the Pleistocene summers were variously colder and wetter than today or less evaporative (more humid). Assuming shell material directly reflects the 180 of the growing-season environment, comparison of modem and fossil shell delta 180 values can potentially identify changes in air-mass moisture sources and can help to define seasonal precipitation change through time. Comprehension and quantification of community and isotopic variability in modem gastropods is required to create probabilistic valid transfer functions with fossil materials. Valid inferences about past environmental conditions can then be established with known confidence limits.

  13. Water resources data, Maryland and Delaware, water year 1999, Volume 1. surface-water data

    USGS Publications Warehouse

    James, Robert W.; Saffer, Richard W.; Tallman, Anthony J.

    2000-01-01

    Water resources data for the 1999 water year for Maryland and Delaware consist of records of stage, discharge, and water quality of streams; stage and contents of lakes and reservoirs. This volume (Volume 1. Surface-Water Data) contains records for water discharge at 111 gaging stations; stage and contents of 1 reservoir; and water quality at 17 gaging stations. Also included are stage and discharge for 3 creststage partial-record stations, discharge only for 27 low-flow partial-record stations, and stage only for 5 tidal crest-stage partial-record stations. Additional water data were collected at various sites not involved in the systematic data-collection program and are published as miscellaneous measurements. These data represent that part of the National Water Data System operated by the U.S. Geological Survey and cooperating State, local, and Federal agencies in Maryland and Delaware.

  14. Water resources data, Maryland and Delaware, water year 1998, volume 1. surface-water data

    USGS Publications Warehouse

    James, Robert W., Jr.; Saffer, Richard W.; Tallman, Anthony

    1999-01-01

    Water resources data for the 1998 water year for Maryland and Delaware consist of records of stage, discharge, and water quality of streams; stage and contents of lakes and reservoirs. This volume (Volume 1. Surface-Water Data) contains records for water discharge at 105 gaging stations; stage and contents of 1 reservoir; and water quality at 16 gaging stations. Also included are stage and discharge for 3 creststage partial-record stations, discharge only for 9 low-flow partial-record stations, and stage only for 5 tidal crest-stage partial-record stations. Additional water data were collected at various sites not involved in the systematic data-collection program and are published as miscellaneous measurements. These data represent that part of the National Water Data System operated by the U.S. Geological Survey and cooperating State, local, and Federal agencies in Maryland and Delaware.

  15. Water resources data, Maryland and Delaware, water year 2001, volume 1. surface-water data

    USGS Publications Warehouse

    James, Robert W.; Saffer, Richard W.; Pentz, Robert H.; Tallman, Anthony J.

    2002-01-01

    Water resources data for the 2001 water year for Maryland and Delaware consist of records of stage, discharge, and water quality of streams; stage and contents of lakes and reservoirs. This volume (Volume 1. Surface-Water Data) contains records for water discharge at 128 gaging stations; stage and contents of 1 reservoir; and water quality at 20 gaging stations. Also included are stage and discharge for 3 creststage partial-record stations and stage only for 10 tidal crest-stage partial-record stations. Additional water data were collected at various sites not involved in the systematic data-collection program and are published as miscellaneous measurements. These data represent that part of the National Water Data System operated by the U.S. Geological Survey and cooperating State, local, and Federal agencies in Maryland and Delaware.

  16. Maximizing conjunctive use of surface and ground water under surface water quality constraints

    NASA Astrophysics Data System (ADS)

    Ejaz, Muhammad Shafqat; Peralta, Richard C.

    A simulation/optimization (s/o) model is presented to address the increasingly common conflicts between water quantity and quality objectives. The model can assist water resources analysts in selecting compromise strategies for stream/aquifer systems in which the stream gains water from the aquifer. The water quantity objective is to maximize steady conjunctive use of groundwater and surface water resources. The water quality objective is to maximize waste loading from a sewage treatment plant (STP) to the stream without violating downstream water quality beyond acceptable limits. The STP discharge is proportional to human population. The two objectives conflict because an increase in groundwater extraction reduces dilution of the stream water contaminants. The result is a decrease in the STP waste loading to the stream and the waste-producing human population that can be supported. The trade-off between objectives is illustrated graphically via sets of noninferior solutions. The sets of noninferior solutions are prepared using the E-constraint method and assuming different upstream flow rates. The s/o model includes superposition expressions describing head and flow responses to decision variables (pumping, diversion, and loadings) and regression expressions describing contaminant concentration responses to these decision variables. Modeled contaminants include: 5-day biochemical oxygen demand, dissolved oxygen, nitrogen (organic, ammonia, nitrite, and nitrate), organic and dissolved phosphorus, total dissolved solids, and chlorophyll- a.

  17. F-LE Snail Invasion

    NSDL National Science Digital Library

    This is a task from the Illustrative Mathematics website that is one part of a complete illustration of the standard to which it is aligned. Each task has at least one solution and some commentary that addresses important asects of the task and its potential use. Here are the first few lines of the commentary for this task: In 1966, a Miami boy smuggled three Giant African Land Snails into the country. His grandmother eventually released them into the garden, and in seven ...

  18. Surface Films: Areas of Water Bodies That Are Often Overlooked

    NSDL National Science Digital Library

    ROGER S. WOTTON and TERENCE M. PRESTON (; )

    2005-02-01

    This peer-reviewed article from BioScience is researching surface water. Material accumulates at the water-air interface of all natural water bodies to form a surface film. The interface is a dynamic environment, so surface films are altered by water movements, solar radiation, and biological processes. These films consist of a complex of organic matter and microorganisms, some of which are harmful. Researchers have often overlooked surface films when studying water bodies, and their importance is only now being recognized.

  19. Water Resources Data, Florida, Water Year 2002, Volume 2A. South Florida Surface Water

    USGS Publications Warehouse

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

    2003-01-01

    Water resources data for 2002 water year in Florida consists of continuous or daily discharge for 392 streams, periodic discharge for 15 streams, continuous or daily stage for 191 streams, periodic stage for 13 stream, peak discharge for 33 streams, and peak stage for 33 streams, continuous or daily elevations for 14 lakes, periodic elevations for 49 lakes, continuous ground-water levels for 418 wells, periodic ground-water levels for 1287 wells, quality of water data for 116 surface-water sites, and 291 wells. The data for South Florida included continuous or daily discharge for 71 streams, continuous or daily stage for 49 streams, no peak stage discharge for streams, 1 continuous elevation for lake, continuous ground-water levels for 238 wells, periodic ground-water levels for 260 wells, water quality for 24 surface-water sites, and 159 wells. The 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.

  20. 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.

  1. Water resources data, Florida, water year 2005. Volume 2A: south Florida surface water

    USGS Publications Warehouse

    Price, C.; Overton, K.

    2006-01-01

    Water resources data for 2005 water year in Florida consists of continuous or daily discharge for 429 streams, periodic discharge for 9 streams, continuous or daily stage for 218 streams, periodic stage for 5 stream, peak discharge for 28 streams, and peak stage for 28 streams, continuous or daily elevations for 15 lakes, periodic elevations for 23 lakes, continuous ground-water levels for 401 wells, periodic ground-water levels for 1,098 wells, quality of water data for 211 surface-water sites, and 208 wells. The data for South Florida included continuous or daily discharge for 91 streams, continuous or daily stage for 62 streams, no peak stage discharge for streams, 1 continuous elevation for lake, continuous ground-water levels for 248 wells, periodic ground-water levels for 187 wells, water quality for 54 surface-water sites, and 121 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.

  2. Water Resources Data, Florida, Water Year 2001, Volume 2A. South Florida Surface Water

    USGS Publications Warehouse

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

    2002-01-01

    Water resources data for 2001 water year in Florida consists of continuous or daily discharge for 404 streams, periodic discharge for 15 streams, continuous or daily stage for 154 streams, periodic stage for 12 stream, peak discharge for 37 streams, and peak stage for 37 streams, continuous or daily elevations for 12 lakes, periodic elevations for 50 lakes, continuous ground-water levels for 426 wells, periodic ground-water levels for 1251 wells, quality of water data for 112 surface-water sites, and 235 wells. The data for South Florida included continuous or daily discharge for 89 streams, continuous or daily stage for 64 streams, no peak stage discharge for streams, 1 continuous elevation for lake, continuous ground-water levels for 244 wells, periodic ground-water levels for 255 wells, water quality for 32 surface-water sites, and 166 wells. The 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.

  3. Water resources data-Florida water year 2004volume 2A: south Florida surface water

    USGS Publications Warehouse

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

    2005-01-01

    Water resources data for 2004 water year in Florida consists of continuous or daily discharge for 405 streams, periodic discharge for 12 streams, continuous or daily stage for 159 streams, periodic stage for 19 stream, peak discharge for 30 streams, and peak stage for 30 streams, continuous or daily elevations for 14 lakes, periodic elevations for 23 lakes, continuous ground-water levels for 408 wells, periodic ground-water levels for 1188 wells, quality of water data for 140 surface-water sites, and 240 wells. The data for South Florida included continuous or daily discharge for 86 streams, continuous or daily stage for 54 streams, no peak stage discharge for streams, 1 continuous elevation for lake, continuous ground-water levels for 257 wells, periodic ground-water levels for 226 wells, water quality for 39 surface-water sites, and 149 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.

  4. Manure Phosphorus and Surface Water Protection III: Transport Factors

    NSDL National Science Digital Library

    This lesson addresses transport factors that may contribute to phosphorus (P) delivery to surface waters.  Erosion, runoff, subsurface flow, drainage, and distance to surface water are the main factors.  In some places, wind erosion may also be important.  The effects of management practices on P transport are discussed, and water-related P transport processes are described in detail. 

  5. Adsorption structure of water molecules on the Be(0001) surface

    SciTech Connect

    Yang, Yu; Li, Yanfang [LCP, Institute of Applied Physics and Computational Mathematics, P.O. Box 8009, Beijing 100088 (China); Wang, Shuangxi [College of Science, China University of Petroleum, Beijing 102249 (China); Zhang, Ping, E-mail: zhang-ping@iapcm.ac.cn [LCP, Institute of Applied Physics and Computational Mathematics, P.O. Box 8009, Beijing 100088 (China); Center for Applied Physics and Technology, Peking University, Beijing 100871 (China)

    2014-06-07

    By using density functional theory calculations, we systematically investigate the adsorption of water molecules at different coverages on the Be(0001) surface. The coverage dependence of the prototype water structures and energetics for water adlayer growth are systematically studied. The structures, energetics, and electronic properties are calculated and compared with other available studies. Through our systematic investigations, we find that water molecules form clusters or chains on the Be(0001) surface at low coverages. When increasing the water coverage, water molecules tend to form a 2?×?2 hexagonal network on the Be(0001) surface.

  6. Water: one molecule, two surfaces, one mistake

    E-print Network

    Vega, Carlos

    2015-01-01

    In order to rigorously evaluate the energy and dipole moment of a certain configuration of molecules one needs to solve the Schr\\"odinger equation. Repeating this for many different configurations allows one to determine the potential energy surface (PES) and the dipole moment surface (DMS). Since the early days of computer simulation it has been implicitly accepted that for empirical potentials the charges used to fit the PES should also be used to describe the DMS. This is a mistake. Partial charges are not observable magnitudes. They should be regarded as adjustable fitting parameters. Optimal values used to describe the PES are not necessarily the best to describe the DMS. One could use two fits: one for the PES, and another for the DMS. This is a common practice in the quantum chemistry community, but not used so often by the community performing computer simulations. This idea affects all types of modelling of water (with the exception of ab-initio calculations) from coarse grained to non-polarizable an...

  7. 60 FR 4664 - Water Quality Standards for Surface Waters of the Sacramento River, San Joaquin River, and San...

    Federal Register 2010, 2011, 2012, 2013, 2014

    1995-01-24

    ...CFR Part 131 Water Quality Standards for Surface Waters of the Sacramento...agriculture-to-agriculture water transfers are...1987 Census of Agriculture, Volume 1...for Surface Waters. EPA-440...information for State Water Resources...

  8. Deterministic assembly of land snail communities according to species size and diet.

    PubMed

    Schamp, Brandon; Horsák, Michal; Hájek, Michal

    2010-07-01

    1. We investigated whether coexisting snail species in 145 treeless fen communities in the Western Carpathian Mountains differed more in size and diet than would be expected by chance, as predicted for traits commonly associated with competition and differential resource acquisition under limiting similarity theory. 2. Contrary to expectations, coexisting snail species were no more different in body size than expected by chance under a null model. However, variation in body size played a significant role in structuring snail communities: coexisting snail species were significantly more similar with respect to body size. 3. We developed two new test statistics to expand our investigation of limiting similarity to include diet, a nominal trait. We tested whether communities of snails were characterized by a greater richness of diet, and whether different diets were represented more or less evenly within communities. Communities of snails were significantly less evenly distributed than expected by chance, with detritivores being over-represented relative to predatory strategies. 4. We also examined the effect of water pH and conductivity, herbaceous cover, and bryophyte and vascular plant richness, on these trends by examining how the effect size of our tests varied across these gradients. Convergence in species size increased with increasing habitat pH. Specifically, smaller snail species were over-represented in fen communities in general, and this effect was accentuated in increasingly calcareous fens. 5. Theory predicts that traits related strongly to environmental conditions are more likely to be convergent. Our findings support this suggestion, as small snail species have an advantage in tolerating freezing conditions over winter when refuges are limited. 6. These results add to the growing body of literature demonstrating that variation in body size and diet play a strong role in structuring communities, although frequently in ways not predicted by limiting similarity theory. Finally, our results increase our understanding of how species are assembled non-randomly into communities with respect to important traits. PMID:20345504

  9. Differences in snail ecology lead to infection pattern variation of Echinostoma spp. larval stages.

    PubMed

    Zimmermann, Michael R; Luth, Kyle E; Esch, Gerald W

    2014-09-01

    The infection patterns of parasites are often tied to host behavior. Although most studies have investigated definitive hosts and their parasites, intermediate host behavior may play a role in shaping the distribution and accumulation of parasites, particularly the larval stages. In an attempt to answer this question, more than 4,500 pulmonate snails were collected from 11 states in the mid-Atlantic and Midwestern United States in the summer of 2012. These snails were necropsied and echinostome metecercariae were commonly observed infecting the snails as 2(nd) intermediate hosts (20.0%). The snails included species of 3 genera with distinct differences in the infection patterns of Echinostoma spp. metacercariae among them. Physa spp. (comprising of P. acuta and P. gyrina) snails exhibited a significantly higher prevalence of infection (23.5%) than both Lymnaea columella (11.6%) and Helisoma spp. (comprising of H. anceps and H. trivolvis) (14.2%; P < 0.05), with no difference in prevalence observed between the latter 2 genera (P > 0.05). The intensity of metacercariae within the snail hosts was significantly different between the 3 genera (P < 0.05), with L. columella having the highest intensity (24.3 ± 5.6), followed by Physa spp. (15.2 ± 1.5) and Helisoma spp. (5.0 ± 0.9). Differences in prevalence and intensity were also observed when the different snail families co-habited the same body of water. The disparities in infection patterns are likely due to distinct differences in the behavioral and feeding ecology of the snail hosts. PMID:25119366

  10. The effects of wetland habitat structure on Florida apple snail density

    USGS Publications Warehouse

    Karunaratne, L.B.; Darby, P.C.; Bennetts, R.E.

    2006-01-01

    Wetlands often support a variety of juxtaposed habitat patches (e.g., grass-, shrub- or tree-dominated) differentially suited to support the inhabiting fauna. The proportion of available habitat types has been affected by human activity and consequently has contributed to degrading habitat quality for some species. The Florida apple snail (Pomacea paludosa) has drawn attention as a critical prey item for wetlands wildlife and as an indicator of wetlands restoration success in peninsular Florida, USA. An apparent contradiction has evolved wherein this species appears intolerant of drying events, but these disturbances may be necessary to maintain suitable habitat structure for apple snails. We recently reported that assertions regarding intolerance to dry downs in this species were inaccurate. Here, we compared snail density in habitats with (wet prairie) and without (slough) emergent macrophytes, as well as evaluating the effects of structural attributes within the broad wet prairie habitat type. Snail densities were greater in prairies relative to sloughs (??2= 12.90, df=1, P=0.0003), often by a factor of two to three. Within wet prairie habitats, we found greater snail densities in Panicum hemitomon as compared to Eleocharis cellulosa (??2=31.45, df=1, P=0.0001). Significantly fewer snails were found in dense E. cellulosa as compared to habitats with lower stem density (??2= 10.73, df=1, P=0.011). Our results indicate that wet prairie habitat supports greater snail densities than nymphaea-dominatd slough. Our results have implications for wetlands water management in that continuous inundation has been shown to convert wet prairie to slough habitat, and we suggest this should be avoided in support of apple snails and their predators. ?? 2006, The Society of Wetland Scientists.

  11. Emerging contaminants in surface waters and their relevance for the production of drinking water in Europe

    Microsoft Academic Search

    Corine J. Houtman

    2010-01-01

    An increasing part of drinking water in Europe is prepared from surface water. At the same time, a growing number of emerging contaminants is being discovered in surface water. This review provides an overview of classes of emerging contaminants nowadays detected in the aquatic environment that are of relevance for drinking water production. These comprise e.g. endocrine disrupting compounds, such

  12. 40 CFR 257.3-3 - Surface water.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...CONTINUED) SOLID WASTES CRITERIA FOR CLASSIFICATION OF SOLID WASTE DISPOSAL FACILITIES AND...Classification of Solid Waste Disposal Facilities and...257.3-3 Surface water. (a) For purposes...areawide or Statewide water quality management plan...

  13. 40 CFR 257.3-3 - Surface water.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...CONTINUED) SOLID WASTES CRITERIA FOR CLASSIFICATION OF SOLID WASTE DISPOSAL FACILITIES AND...Classification of Solid Waste Disposal Facilities and...257.3-3 Surface water. (a) For purposes...areawide or Statewide water quality management plan...

  14. 40 CFR 257.3-3 - Surface water.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...CONTINUED) SOLID WASTES CRITERIA FOR CLASSIFICATION OF SOLID WASTE DISPOSAL FACILITIES AND...Classification of Solid Waste Disposal Facilities and...257.3-3 Surface water. (a) For purposes...areawide or Statewide water quality management plan...

  15. Hydraulic "Fracking": Are Surface Water Impacts An Ecological Concern?

    E-print Network

    Hydraulic "Fracking": Are Surface Water Impacts An Ecological Concern? G. Allen Burton Jr; Fracking; Water-quality stressor; Ecological risk assessment Introduction The world's energy marketplace) operations targeting shale gas (and oil) formations, coupled with mounting health, environme

  16. Field evaluation of controlled release copper glass as a molluscicide in snail control.

    PubMed

    Chandiwana, S K; Ndamba, J; Makura, O; Taylor, P

    1987-01-01

    Limited field evaluation of a new molluscicide, copper controlled release glass (CRG), was carried out in 4 human water contact sites in shallow and slow flowing streams in the highveld region of Zimbabwe during 1984 to 1986. The results indicate that the copper CRG has great potential as an inexpensive snail control agent to reduce schistosomiasis transmission. There was a marked reduction in snail numbers in the treated sites after application of 2 forms of the copper molluscicide; a "fast" CRG with approximately 24-h solution time in water and a "slow" CRG with about 1-year solution time. Snail numbers remained depressed during the observation period while frogs and fish were not affected. Fluctuations in snail numbers in the untreated sites showed no clear pattern, being erratic and unpredictable and probably attributable to seasonal effects. Problems of the correct amounts of molluscicide to apply to a site are to an extent overcome by knowledge of the copper binding capacity of the mud substrate. The mud sediment can be saturated by the "fast" release copper glass to achieve a snail killing concentration in the water which can be sustained by the "slow" release glass. It appears that the main difficulty in maintaining desirable copper levels in the water is flow, which causes rapid removal of copper from the treated waterbody. Thus, under field conditions on the highveld region of Zimbabwe, the CRG molluscicide is likely to be effective only during the stable conditions of the dry season which is, however, the main transmission period. PMID:3503415

  17. SURFACE WATER MONITORING SYSTEM INSTALLED ON BOARD THE ICEBREAKER SHIRASE

    Microsoft Academic Search

    Mitsuo FUKUCHI; Hiroshi HATTORI

    A surface water monitoring system was designed and installed on board the icebreaker SHIRASE. The system consists of sensors unit, navigation information terminal and control unit. Water pumped up from an intake of hull (8 m depth) is led into the sensors unit so as to measure flow rate of water, water temperature, conductivity, dissolved oxygen, fluorescence intensity, size com

  18. How protein surfaces induce anomalous dynamics of hydration water.

    PubMed

    Pizzitutti, Francesco; Marchi, Massimo; Sterpone, Fabio; Rossky, Peter J

    2007-07-01

    Water around biomolecules slows down with respect to pure water, and both rotation and translation exhibit anomalous time dependence in the hydration shell. The origin of such behavior remains elusive. We use molecular dynamics simulations of water dynamics around several designed protein models to establish the connection between the appearance of the anomalous dynamics and water-protein interactions. For the first time we quantify the separate effect of protein topological and energetic disorder on the hydration water dynamics. When a static protein structure is simulated, we show that both types of disorder contribute to slow down water diffusion, and that allowing for protein motion, increasing the spatial dimensionality of the interface, reduces the anomalous character of hydration water. The rotation of water is, instead, altered by the energetic disorder only; indeed, when electrostatic interactions between the protein and water are switched off, water reorients even faster than in the bulk. The dynamics of water is also related to the collective structure--à voir the hydrogen bond (H-bond) network--formed by the solvent enclosing the protein surface. We show that, as expected for a full hydrated protein, when the protein surface offers pinning sites (charged or polar sites), the superficial water-water H-bond network percolates throughout the whole surface, hindering the water diffusion, whereas it does not when the protein surface lacks electrostatic interactions with water and the water diffusion is enhanced. PMID:17564431

  19. Unsteady forces on spheres during free-surface water entry

    E-print Network

    Truscott, Tadd T.

    We present a study of the forces during free-surface water entry of spheres of varying masses, diameters, and surface treatments. Previous studies have shown that the formation of a subsurface air cavity by a falling sphere ...

  20. Controlling slugs and snails in orchids

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Slugs and snails are pests of orchids, preferring tender plant tissues such as flowers and root tips. Unlike many insect pests which feed only on certain types of plants, most species of slugs and snails are generalists, feeding on green plants, algae, fungi, decaying plant matter, or decaying anima...

  1. Inquiry, Land Snails, and Environmental Factors

    ERIC Educational Resources Information Center

    Barrow, Lloyd H.; Krantz, Patrick D.

    2005-01-01

    Land snails are common invertebrates that fascinate children. Unfortunately, they are seldom used for activities in the science classroom. Snails are inexpensive, take up little space in the classroom, and require only low maintenance, and their learning dividends can be enormous. For example, students can use them in inquiry-based activities that…

  2. Water-A New Player of the Solid Surface

    NASA Astrophysics Data System (ADS)

    Gao, Yi; Li, Yadong; Zhu, Beien

    2015-03-01

    It is well-known that water configuration and behaviors are highly affected by the solid surface. On the other hand, water is generally considered to have negligible effects on the solid surface. But it might not be the case. Here, we theoretically present two examples to show water could significantly affect the surface structure and properties. The water molecule adsorption could induce the migration of the subsurface vacancies and the change of the surface elements population. These observations might give us a new perspective to understand the properties of liquid/solid interfaces.

  3. Combined Visualization of Wind Waves and Water Surface Temperature

    E-print Network

    Jaehne, Bernd

    Combined Visualization of Wind Waves and Water Surface Temperature Roland Rocholz1 , Sven Wanner1 comparison of the space-time evolution of the waves and the surface temperature distribution . The temperature images are mapped in false color onto that virtual surface. Shading, based on the surface slope

  4. Field and laboratory evaluation of the influence of copper-diquat on apple snails in southern Florida

    USGS Publications Warehouse

    Winger, P.V.; Imlay, M.J.; McMillan, W.E.; Martin, T.W.; Takekawa, J.; Johnson, W.W.

    1984-01-01

    The recent decline of apple snail (Pomacea paludosa) populations in canals surrounding Loxahatchee National Wildlife Refuge in southern Florida coincided with the use of copper-diquat for the control of the aquatic weed hydrilla (Hydrilla ver/icillara). Field and laboratory studies were designed to assess the effects of copper-diquat on apple snails, which are the primary food of the endangered snail kite Rostrhamus sociabilis (formerly known as the Everglade kite). Acute toxicities (96-h LC50 values) of Cutrine-Plus and Komeen (chelated formulations of copper) to immature apple snails were 22 and 241-?g/L, respectively. Diquat was toxic at a concentration of 1,800 I-?g/L and did not increase the toxicity of copper when the chemicals were used in combination. Evaluation of field samples indicated that copper concentrations were higher in detritus than in water. plants and mud, and that there was a gradient of copper concentration from the canal to the interior, the highest residues being in samples from the canal. Copper associated with detritus (up to 150 ?g/g) had no effect on growth or survival of apple snails in field cage and tank studies. Also, field applications of copper.diquat to hydrilla had no effect on survival of caged adult and immature snails. Copper from field applications was rapidly taken out of solution by plants and organic material in the water and subsequently incorporated into the bottom detritus. Although the effects of repeated applications of copper-diquat and high body burdens of copper (accumulated during exposure to herbicidal treatment) on survival and reproduction of apple snails are not known, the information available indicates that treatment of hydrilla with copper-diquat was probably not responsible for the decline in the apple snail population. Application at recommended rates should pose no threat to these snails in the organically rich waters of southern Florida.

  5. Structure of water adsorbed on a mica surface

    SciTech Connect

    Park, Sung-Ho; Sposito, Garrison

    2002-01-29

    Monte Carlo simulations of hydration water on the mica (001) surface under ambient conditions revealed water molecules bound closely to the ditrigonal cavities in the surface, with a lateral distribution of approximately one per cavity, and water molecules interposed between K{sup +} counter ions in a layer situated about 2.5 {angstrom} from a surface O along a direction normal to the (001) plane. The calculated water O density profile was in quantitative agreement with recent X-ray reflectivity measurements indicating strong lateral ordering of the hydration water but liquid-like disorder otherwise.

  6. How Water Meets a Hydrophobic Surface: Reluctantly and with Fluctuations

    NASA Astrophysics Data System (ADS)

    Poynor, Adele; Hong, Liang; Granick, Steve; Robinson, Ian; Fenter, Paul; Zhang, Zhan

    2007-03-01

    By definition hydrophobic substances hate water. Water placed on a hydrophobic surface will form a drop in order to minimize its contact area. What happens when water is forced into contact with a hydrophobic surface? One theory is that an ultra-thin low- density region forms near the surface. To investigate the existence of this layer, we have employed three surface sensitive techniques, time-resolved phase-modulated ellipsometry, surface plasmon resonance, and X-ray reflectivity. Both ellipsometry and X-ray reflectivity provide strong evidence for the low-density layer and illuminate unexpected temporal behavior.

  7. Activities affecting surface water resources: A general overview

    SciTech Connect

    Not Available

    1990-01-01

    In November 1987, P.E.I. signed a federal/provincial work-sharing arrangement on water resource management focusing on groundwater pollution, surface water degradation and estuarine eutrophication. The surface water program was designed to identify current surface water uses and users within 12 major watersheds across the Island containing 26 individual rivers, as well as problems arising due to practices that degrade the quality of surface water and restricts its value to other user groups. This report presents a general overview of the program, covering the general characteristics of the Island; operations in agriculture, fish and wildlife, forestry, recreation, fisheries, and industry; alterations of natural features of waterways; wetlands; additional watershed activities such as hydrometric stations and subdivision development; and activities affecting surface water resources such as sedimentation sources, pollution point sources and instream obstructions.

  8. Electrostatic painting of nonconductive surfaces with water-base paints

    SciTech Connect

    Inculet, I.I. [Univ. of Western Ontario, London, Ontario (Canada). Dept. of Electrical Engineering] [Univ. of Western Ontario, London, Ontario (Canada). Dept. of Electrical Engineering; Klein, R.G. [Nordson Corp., Westlake, OH (United States)] [Nordson Corp., Westlake, OH (United States)

    1996-01-01

    Electrostatic corona painting on nonconductive surfaces normally requires a ground-connected conductive precoating of the surface in order to dissipate the continuously incoming ionic charge from the corona gun. If the surface charge does not flow to ground, the resulting surface electric field will repel a substantial amount of the incoming paint. The authors present a new painting method consisting of generating ultrasonically atomized electrically charged water particles behind the nonconductive surface to be painted. The paint spraying is carried out with a mechanical spray gun maintained at ground potential. The water base paint becomes charged by induction under the influence of the space charge behind the nonconductive surface to be painted. As the resulting charge on the water base paint particles is of opposite polarity to that of the ultrasonically atomized electrically charged water particles cloud, all propelling electric fields converge toward the surface to be painted. The results show excellent transfer efficiencies.

  9. Atmospheric surface layer turbulence over water surfaces and sub-grid scale physics

    E-print Network

    Bou-Zeid, Elie

    -optic temperature profiler (1 meter above the water surface and 2 meters below), and (3) a lake current profiler and the implications for large-eddy simulations (LES) of turbulent atmospheric flows over water surfaces. #12;2 Bou the water. At mid day and in the afternoon, as the air heats up over land and flows over the lake, H tends

  10. MAIC-2, a latitudinal model for the Martian surface temperature, atmospheric water transport and surface glaciation

    Microsoft Academic Search

    Ralf Greve; Bjoern Grieger; Oliver J. Stenzel

    2010-01-01

    The Mars Atmosphere-Ice Coupler MAIC-2 is a simple, latitudinal model, which consists of a set of parameterisations for the surface temperature, the atmospheric water transport and the surface mass balance (condensation minus evaporation) of water ice. It is driven directly by the orbital parameters obliquity, eccentricity and solar longitude (Ls) of perihelion. Surface temperature is described by the Local Insolation

  11. Water accounting for conjunctive groundwater/surface water management: case of the SingkarakOmbilin

    E-print Network

    Walter, M.Todd

    groundwater levels. q 2004 Elsevier B.V. All rights reserved. Keywords: Water accounting; Water balanceWater accounting for conjunctive groundwater/surface water management: case of the Singkarak University, 216 Riley-Robb Hall, Ithaca, NY 14853-5701, USA b International Water Management Institute, P

  12. Molecular dynamics studies of interfacial water at the alumina surface.

    SciTech Connect

    Argyris, Dr. Dimitrios [University of Oklahoma; Ho, Thomas [ORNL; Cole, David [Ohio State University

    2011-01-01

    Interfacial water properties at the alumina surface were investigated via all-atom equilibrium molecular dynamics simulations at ambient temperature. Al-terminated and OH-terminated alumina surfaces were considered to assess the structural and dynamic behavior of the first few hydration layers in contact with the substrates. Density profiles suggest water layering up to {approx}10 {angstrom} from the solid substrate. Planar density distribution data indicate that water molecules in the first interfacial layer are organized in well-defined patterns dictated by the atomic terminations of the alumina surface. Interfacial water exhibits preferential orientation and delayed dynamics compared to bulk water. Water exhibits bulk-like behavior at distances greater than {approx}10 {angstrom} from the substrate. The formation of an extended hydrogen bond network within the first few hydration layers illustrates the significance of water?water interactions on the structural properties at the interface.

  13. Models of Fate and Transport of Pollutants in Surface Waters

    ERIC Educational Resources Information Center

    Okome, Gloria Eloho

    2013-01-01

    There is the need to answer very crucial questions of "what happens to pollutants in surface waters?" This question must be answered to determine the factors controlling fate and transport of chemicals and their evolutionary state in surface waters. Monitoring and experimental methods are used in establishing the environmental states.…

  14. TILLAGE EFFECTS ON NEAR SURFACE SOIL WATER DYNAMICS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Tillage modifies the soil physical properties near the surface which in turn can influence evaporation rates and how water is redistributed within the profile during and after precipitation. The objective of this study was to evaluate the effects of sweep tillage on near surface soil water dynamics....

  15. 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.

  16. Remote surface water monitoring radio based telemetry system

    Microsoft Academic Search

    W. L. Goodwin; D. Baxter

    1993-01-01

    The Environmental Protection Department of EG&G Rocky Flats has designed and developed a unique Remote Surface Water Monitoring System using radio telemetry hardware and computer control software. The system is based on new technologies in microelectronics and environmental monitoring sensors. An engineering team, headed up by the Surface Water Division at EG&G, has proven that with careful evaluation of new

  17. Total Alkalinity of Surface Waters—A National Map

    Microsoft Academic Search

    James M. Omernik; Charles F. Powers

    1983-01-01

    This map illustrates the regional patterns of mean annual alkalinity of surface water in the conterminous United States. As such, it affords a qualitative graphic overview to the sensitivity of surface waters to acidification. The map is based on data from approximately 2,500 streams and lakes and apparent spatial correlations between these data and macrowatershed characteristics, especially land use.

  18. Fouling of quartz surfaces in potable water ultraviolet disinfection reactors

    Microsoft Academic Search

    Isaac William Wait

    2005-01-01

    Although ultraviolet (UV) disinfection of drinking water has been shown to be effective and cost efficient, one barrier to more widespread adoption is uncertainty surrounding the possible accumulation of fouling materials on quartz surfaces within UV reactors. These quartz surfaces serve as protection for the UV lamps that are immersed in the water being treated, and in many cases they

  19. TOTAL ALKALINITY OF SURFACE WATERS OF THE US

    EPA Science Inventory

    This map provides a synoptic illustration of the national patterns of surface water alkalinity in the conterminous United States. Alkalinity is the most readily available measure of the acid-neutralizing capacity of surface waters and provides a reasonable estimate o...

  20. Levity Through Tension: Fun with Water's Surface Tension

    NSDL National Science Digital Library

    Children's Museum of Houston

    2011-01-01

    This experiment describes how to create a "dribble bottle" which only leaks water when the cap is unscrewed. The full water bottle has a small hole made with a push pin. The surface tension of water is strong enough to keep the small pin hole sealed. When the bottle is open, air can enter the bottle through the top, and air pressure overcomes the surface tension, pushing water out the small hole. In a related video, Mr. O and his assistants explore surface tension with a variety of similar experiments.

  1. Surface Tension: The Ways of Water.

    ERIC Educational Resources Information Center

    Donalson-Sams, Marilyn

    1988-01-01

    Describes activities which help students understand several basic scientific concepts regarding water. Outlines objectives, materials needed, procedures, and questions to ask about student observations. Investigations include working with the self-sealing property of water, talcum powder, paper clips, and making water wetter. (RT)

  2. Water resources data, New Jersey, water year 2005. Volume 1 - surface-water data

    USGS Publications Warehouse

    White, B.T.; Hoppe, H.L.; Centinaro, G.L.; Dudek, J.F.; Painter, B.S.; Protz, A.R.; Reed, T.J.; Shvanda, J.C.; Watson, A.F.

    2006-01-01

    Water-resources data for the 2005 water year for New Jersey are presented in three volumes, and consists of records of stage, discharge, and water-quality of streams; stage and contents of lakes and reservoirs; and water levels and water-quality of ground water. Volume 1 contains discharge records for 103 gaging stations; tide summaries at 28 tidal gaging stations; stage and contents at 34 lakes and reservoirs; and diversions from 50 surface-water sources. Also included are stage and discharge for 116 crest-stage partial-record stations, stage-only at 33 tidal crest-stage gages, and discharge for 155 low-flow partial-record stations. Locations of these sites are shown in figures 8-11. Additional discharge measurements were made at 222 miscellaneous sites that are not part of the systematic data-collection program. Discontinued station tables for gaging stations, crest-stage gages, tidal crest-stage and tidal gaging stations show historical coverage. The data in this report represent that part of the National Water Information System (NWIS) data collected by the United States Geological Survey (USGS). Hydrologic conditions are also described for this water year, including stream-flow, precipitation, reservoir conditions, and air temperatures.

  3. Availability of Water In The Upper Martian Surface

    Microsoft Academic Search

    D. Moehlmann

    2002-01-01

    Availability of water in the upper Martian surface D. Möhlmann, DLR Institut für Raumsimulation51170, Köln,Germany Email:dirk.moehlmann@dlr.de It is the cur- rent opinion that at present water in the upper Martian surface is in the ice-phase. This ice can be found, if at all, at mid- and equatorial latitudes only in depths of decameters or deeper. Thus, water is expected to

  4. Diffuse pollution of surface water by pharmaceutical products

    Microsoft Academic Search

    J. G. M. Derksen; G. B. J. Rijs; R. H. Jongbloed

    2004-01-01

    Pharmaceutical products for humans or animals, as well as their related metabolites (degradation products) end up in the aquatic environment after use. Recent investigations from abroad show that low concentrations of pharmaceuticals are detectable in municipal waste water, surface water, groundwater and even drinking water. Little is known about the effects, and with that the risk, of long term exposure

  5. Water Order Profiles on Phospholipid/Cholesterol Membrane Bilayer Surfaces

    E-print Network

    O'Shea, Paul

    Water Order Profiles on Phospholipid/Cholesterol Membrane Bilayer Surfaces DAVID ROBINSON,1 2011 in Wiley Online Library (wileyonlinelibrary.com). Abstract: Water is pivotal in the stabilization of macromolecular biological structures, although the dynamic en- semble structure of water near to molecular

  6. Effects of Sublethal Chronic Copper Exposure on the Growth and Reproductive Success of the Florida Apple Snail ( Pomacea paludosa )

    Microsoft Academic Search

    Emily C. Rogevich; Tham C. Hoang; Gary M. Rand

    2009-01-01

    Florida apple snails (Pomacea paludosa) were exposed to three concentrations of copper (Cu), in water (8 ?g\\/L, 16 ?g\\/L, 24 ?g\\/L), for one generation to examine\\u000a uptake and the effects on survival, growth, and reproduction of the F0 generation and survival, growth, and whole body Cu of the F1 generation. During a 9-month Cu exposure, apple snails exposed to 8–16 ?g\\/L Cu had high Cu

  7. SURFACE AND SUBSURFACE WATER QUALITY HYDROLOGY IN SURFACE MINED WATERSHEDS. PART I: TEXT

    EPA Science Inventory

    Surface mining disturbs the natural sequence of geologic strata, and, therefore, potentially modifies the quantity and quality of water on a watershed disturbed by surface mining. Such a watershed disturbed by surface mining was monitored in Colorado. In addition, surface runoff,...

  8. Enhanced ordering of water at hydrophobic surfaces

    NASA Astrophysics Data System (ADS)

    Strazdaite, Simona; Versluis, Jan; Backus, Ellen H. G.; Bakker, Huib J.

    2014-02-01

    We study the properties of water molecules adjacent to a hydrophobic molecular layer with vibrational sum-frequency generation spectroscopy. We find that the water molecules at D2O/hexane, D2O/heptane, and D2O/polydimethylsiloxane interfaces show an enhanced ordering and stronger hydrogen-bond interactions than the water molecules at a D2O/air interface. With increasing temperature (up to 80 °C) the water structure becomes significantly less ordered and the hydrogen bonds become weaker.

  9. Fluctuating Helical Asymmetry and Morphology of Snails (Gastropoda) in Divergent Microhabitats at ‘Evolution Canyons I and II,’ Israel

    PubMed Central

    Raz, Shmuel; Schwartz, Nathan P.; Mienis, Hendrik K.; Nevo, Eviatar; Graham, John H.

    2012-01-01

    Background Developmental instability of shelled gastropods is measured as deviations from a perfect equiangular (logarithmic) spiral. We studied six species of gastropods at ‘Evolution Canyons I and II’ in Carmel and the Galilee Mountains, Israel, respectively. The xeric, south-facing, ‘African’ slopes and the mesic, north-facing, ‘European’ slopes have dramatically different microclimates and plant communities. Moreover, ‘Evolution Canyon II’ receives more rainfall than ‘Evolution Canyon I.’ Methodology/Principal Findings We examined fluctuating asymmetry, rate of whorl expansion, shell height, and number of rotations of the body suture in six species of terrestrial snails from the two ‘Evolution Canyons.’ The xeric ‘African’ slope should be more stressful to land snails than the ‘European’ slope, and ‘Evolution Canyon I’ should be more stressful than ‘Evolution Canyon II.’ Only Eopolita protensa jebusitica showed marginally significant differences in fluctuating helical asymmetry between the two slopes. Contrary to expectations, asymmetry was marginally greater on the ‘European’ slope. Shells of Levantina spiriplana caesareana at ‘Evolution Canyon I,’ were smaller and more asymmetric than those at ‘Evolution Canyon II.’ Moreover, shell height and number of rotations of the suture were greater on the north-facing slopes of both canyons. Conclusions/Significance Our data is consistent with a trade-off between drought resistance and thermoregulation in snails; Levantina was significantly smaller on the ‘African’ slope, for increasing surface area and thermoregulation, while Eopolita was larger on the ‘African’ slope, for reducing water evaporation. In addition, ‘Evolution Canyon I’ was more stressful than Evolution Canyon II’ for Levantina. PMID:22848631

  10. Antipredatory behavior as an index of heavy-metal pollution? A test using snails and caddisflies.

    PubMed

    Lefcort, H; Ammann, E; Eiger, S M

    2000-04-01

    The loss of behaviors that organisms use to avoid predation may serve as a sensitive indicator of pollution. We tested the hypothesis that a correlation exists in the field between heavy metal levels and antipredator behaviors. We examined the antipredator behavior of aquatic caddisfly larvae and snails at sites in the Coeur d'Alene basin of Northern Idaho which varied in their levels of heavy metals. We tested the antipredator response of Physella columbiana snails at 10 polluted lakes downstream from the Bunker Hill Environmental Protection Agency (EPA) Superfund cleanup site. We then compared their behavior to snails at 14 reference lakes. We placed the snails in a plastic testing apparatus, exposed them to an extract of crushed snail, and then monitored their movements to a normally preferred shaded area. We also tested the behavior of caddisfly larvae from 36 sites from a total of 6 streams/rivers adjacent to the Superfund site. Sites were located upstream and downstream of abandoned mines. We located active larvae of four genera, simulated predation by grasping the animals between thumb and forefinger (the larvae respond to being grasped by withdrawing into their case), lifted them from the water for 3 s, and then placed them in an adjacent, slower section of the stream. We then recorded how long it took each larvae to partially emerge from its case and attempt to move away. Unlike reference site snails, snails from heavy metal-polluted environments failed to exhibit antipredator behaviors in response to crushed conspecifics. These results are consistent with previous laboratory studies. We found no effect of heavy metals on the antipredatory behavior of caddisfly larvae. PMID:10667928

  11. Interaction between water cluster ions and mica surface

    SciTech Connect

    Ryuto, Hiromichi, E-mail: ryuto@kuee.kyoto-u.ac.jp; Ohmura, Yuki; Nakagawa, Minoru; Takeuchi, Mitsuaki; Takaoka, Gikan H. [Photonics and Electronics Science and Engineering Center, Kyoto University, Nishikyo, Kyoto 615-8510 (Japan)

    2014-03-15

    Water cluster ion beams were irradiated on mica surfaces to investigate the interaction between molecular cluster ions and a mica surface. The contact angle of the mica surface increased with increasing dose of the water cluster ion beam, but the increase in the contact angle was smaller than that induced by an ethanol cluster ion beam. The surface roughness also increased with increasing dose of the water cluster ion beam, whereas the intensity of K 2p x-ray photoelectron spectroscopy peaks decreased with increasing dose of the water cluster ion beam. The decrease in the number of potassium atoms together with the increase in the surface roughness may be the causes of the increase in the contact angle.

  12. Availability of Water In The Upper Martian Surface

    NASA Astrophysics Data System (ADS)

    Moehlmann, D.

    Availability of water in the upper Martian surface D. Möhlmann, DLR Institut für Raumsimulation51170, Köln,Germany Email:dirk.moehlmann@dlr.de It is the cur- rent opinion that at present water in the upper Martian surface is in the ice-phase. This ice can be found, if at all, at mid- and equatorial latitudes only in depths of decameters or deeper. Thus, water is expected to exist in the Martian surface far away from layers which are reached by the diurnal or seasonal solar radiation caused thermal wave. On the other side, morning fog indicates at some locations the existence of water in the upper surface layers, what are by definition those, which can be reached by the ther- mal wave. It is assumed since Viking (Jakosky et al., 1997) that this water has to be expected to be bound to the soil as adsorbate water in the upper surface l ayers above the ice in deeper layers. Model results are presented, which indicate for different soil parameters the possible amount of absorbate water in the upper Martian surface. It is expected that this adsorbate water may well be of biological importance.

  13. Reduced water density at hydrophobic surfaces: Effect of dissolved gases

    PubMed Central

    Doshi, Dhaval A.; Watkins, Erik B.; Israelachvili, Jacob N.; Majewski, Jaroslaw

    2005-01-01

    Here, direct noninvasive neutron reflectivity measurements reveal the presence of a reduced (deuterated) water density region, with a sigmoidal density profile at the hydrophobic silane–water interface that depends on the type and concentration of dissolved gases in the water. Removal of dissolved gases decreases the width of the reduced water density region, and their reintroduction leads to its increase. When compared with recent computer simulations, a locally fluctuating density profile is proposed, whereas preexisting nanobubbles are excluded. The presence of a fluctuating reduced water density region between two hydrophobic surfaces and the attractive “depletion force” to which it leads may help explain the hydrophobic force and its reported diminution in deaerated water. Our results are also quantitatively consistent with recent dynamic surface force apparatus results that drastically revise previous estimates of the slip length of water flowing past hydrophobic surfaces from microns to ?20 nm. Our observations, therefore, go a long way toward reconciling three quite different types of experiments and phenomena: water depletion at hydrophobic surfaces, water slip at hydrophobic surfaces, and the hydrophobic interaction. PMID:15976022

  14. Georgia's Surface-Water Resources and Streamflow Monitoring Network, 2008

    USGS Publications Warehouse

    U.S. Geological Survey

    2008-01-01

    Surface water provides 5 billion gallons per day, or 78 percent, of the total freshwater used (including thermoelectric) in Georgia (Fanning, 2003). Climate, geology, and landforms control the natural distribution of Georgia's water resources. Georgia is a 'headwaters' State, with most of the rivers beginning in northern Georgia and increasing in size downstream (see map at right for major watersheds). Surface water is the primary source of water in the northern one-half of the State, including the Atlanta metropolitan area, where limited ground-water resources are difficult to obtain. In Georgia, periodic droughts exacerbate competition for surface-water supplies. Many areas of Georgia also face a threat of flooding because of spring frontal thunderstorms and the potential for hurricanes from both the Atlantic Ocean and Gulf of Mexico. As the population of Georgia increases, these flood risks will increase with development in flood-risk zones, particularly in the coastal region.

  15. Water Quality Indicators Guide [and Teacher's Handbook]: Surface Waters.

    ERIC Educational Resources Information Center

    Terrell, Charles R.; Perfetti, Patricia Bytnar

    This guide aids in finding water quality solutions to problems from sediment, animal wastes, nutrients, pesticides, and salts. The guide allows users to learn the fundamental concepts of water quality assessment by extracting basic tenets from geology, hydrology, biology, ecology, and wastewater treatment. An introduction and eight chapters are…

  16. Chloride in ground water and surface water in the vicinity of selected surface-water sampling sites of the beneficial use monitoring program of Oklahoma, 2003

    USGS Publications Warehouse

    Mashburn, Shana L.; Sughru, Michael P.

    2004-01-01

    The Oklahoma Water Resources Board Beneficial Use Monitoring Program reported exceedances of beneficial-use standards for chloride at 11 surface-water sampling sites from January to October 2002. The U.S. Geological Survey, in cooperation with the Oklahoma Department of Environmental Quality, conducted a study to determine the chloride concentrations in ground water in the vicinity of Beneficial Use Monitoring Program surface-water sampling sites not meeting beneficial use standards for chloride and compare chloride concentrations in ground water and surface water. The chloride-impaired Beneficial Use Monitoring Program surface-water sampling sites are located in the western and southern regions of Oklahoma. The ground-water sampling sites were placed in proximity to the 11 surface-water sampling sites designated impaired by chloride by the Oklahoma Water Resources Board. Two surface-water sampling sites were located on the Beaver River (headwaters of the North Canadian River), three sites on the Cimarron River, one site on Sandy Creek, one site on North Fork Red River, and four sites on the Red River. Six ground-water samples were collected, when possible, from two test holes located upstream from each of the 11 Beneficial Use Monitoring Program surface-water sampling sites. One test hole was placed on the left bank and right bank, when possible, of each Beneficial Use Monitoring Program surfacewater sampling site. All test holes were located on alluvial deposits adjacent to the Beneficial Use Monitoring Program surface-water sampling sites within 0.5 mile of the stream. Top, middle, and bottom ground-water samples were collected from the alluvium at each test hole, when possible. Water properties of specific conductance, pH, water temperature, and dissolved oxygen were recorded in the field before sampling for chloride. The ground-water median chloride concentrations at 8 of the 11 Beneficial Use Monitoring Program sites were less than the surface-water median chloride concentrations. The Turpin and Beaver sites had similar ground-water and surface-water median chloride concentrations. The Buffalo site was the only site that had a large difference between the ground-water and surface-water chloride concentrations. The ground-water median chloride concentration was approximately 14,500 mg/L greater than the surface-water median chloride concentration at the Buffalo site.

  17. The interaction of water with environmentally relevant surfaces

    SciTech Connect

    Andersson, K.; Yamamoto, S.; Ketteler, G.; Starr, D.E.; Nilsson, A.; Salmeron, M.; Bluhm, H.

    2006-04-05

    Probing the coverage and chemical speciation of molecules at surfaces are of fundamental interest in molecular environmental science. The concentration of water and its dissociation fragments at surfaces affect many highly important interfacial chemical processes and there exist no previous quantitative determinations of the coverage of water on clean metal surfaces at near ambient conditions. We have utilized Ambient Pressure Photoelectron Spectroscopy (AP-PES) to study the water/Cu(111) and Cu(110) systems at pressures up to 1 Torr in the temperature range 270-470 K.

  18. In Vitro Effects of Mucus from the Mantle of Compatible (Lymnaea elodes) and Incompatible (Helisoma trivolvis) Snail Hosts on Fascioloides magna Miracidia.

    PubMed

    Coyne, Kathyrn; Laursen, Jeffrey R; Yoshino, Timothy P

    2015-06-01

    The epidermal mucus covering the surface of a snail represents an important barrier to trematode larvae attempting to penetrate the snail and may play a role in mediating snail-trematode compatibility. In this study, Facioloides magna miracidia were exposed to mucus harvested from a compatible snail host, Lymnaea elodes (palustris), and from an incompatible snail, Helisoma trivolvis . In vitro treatment of freshly hatched miracidia with snail-derived mucus exerted dramatically different effects on larvae depending on snail species. At the lowest dilution of mucus tested (1:3) mean damage rates (tegumental damage and/or larval lysis and death) were as high as 100% for miracidia exposed to H. trivolvis mucus, while none of F. magna miracidia were damaged in L. elodes mucus. A dilution series for each snail species, and treatments with heat and proteinase K were performed to characterize the component(s) of mucus inducing the observed morphological changes. The damaging effects of H. trivolvis mucus were concentration dependent and completely abrogated by heat (65 C, 30 min) and proteinase treatment, strongly implicating a heat-labile protein(s) in mucus as the active cytotoxic agent(s). In contrast to our prediction that miracidial contact with mucus of compatible L. elodes would trigger larval transformation, mucus from either snail species tested exhibited little to no activity. Overall these data demonstrate the presence of a potent cytotoxic protein-like factor in the mucus of F. magna -incompatible H. trivolvis , and its absence in the mucus of the compatible snail, L. elodes . This finding supports the notion that the epidermal mucus layer may be serving as an important determinant of larval trematode-snail compatibility. PMID:25602486

  19. Evaporation from the free water surface of a flooded forest

    NASA Astrophysics Data System (ADS)

    Newman, A.; Keim, R.; Hiscox, A.

    2011-12-01

    Controls on evaporation rates from the free water surface of flooded forests have received little attention despite being an important component of the water balance in wetlands. In flooded forests, the tree canopy reduces solar radiation and turbulent exchange, so evaporation rates are lower than from an open water body. We measured evaporation from the free water surface in a flooded cypress/tupelo forest in southern Louisiana, USA, using both Bowen-ratio energy balance and eddy covariance methods. We compare results, which to our knowledge comprise the first experimental data set of evaporation rates in a flooded forest, to rates predicted by a simple empirical model.

  20. Schistosomes and snails: a molecular encounter.

    PubMed

    Knight, Matty; Arican-Goktas, Halime D; Ittiprasert, Wannaporn; Odoemelam, Edwin C; Miller, André N; Bridger, Joanna M

    2014-01-01

    Biomphalaria glabrata snails play an integral role in the transmission of Schistosoma mansoni, the causative agent for human schistosomiasis in the Western hemisphere. For the past two decades, tremendous advances have been made in research aimed at elucidating the molecular basis of the snail/parasite interaction. The growing concern that there is no vaccine to prevent schistosomiasis and only one effective drug in existence provides the impetus to develop new control strategies based on eliminating schistosomes at the snail-stage of the life cycle. To elucidate why a given snail is not always compatible to each and every schistosome it encounters, B. glabrata that are either resistant or susceptible to a given strain of S. mansoni have been employed to track molecular mechanisms governing the snail/schistosome relationship. With such snails, genetic markers for resistance and susceptibility were identified. Additionally, differential gene expression studies have led to the identification of genes that underlie these phenotypes. Lately, the role of schistosomes in mediating non-random relocation of gene loci has been identified for the first time, making B. glabrata a model organism where chromatin regulation by changes in nuclear architecture, known as spatial epigenetics, orchestrated by a major human parasite can now be investigated. This review will highlight the progress that has been made in using molecular approaches to describe snail/schistosome compatibility issues. Uncovering the signaling networks triggered by schistosomes that provide the impulse to turn genes on and off in the snail host, thereby controlling the outcome of infection, could also yield new insights into anti-parasite mechanism(s) that operate in the human host as well. PMID:25101114

  1. Schistosomes and snails: a molecular encounter

    PubMed Central

    Knight, Matty; Arican-Goktas, Halime D.; Ittiprasert, Wannaporn; Odoemelam, Edwin C.; Miller, André N.; Bridger, Joanna M.

    2014-01-01

    Biomphalaria glabrata snails play an integral role in the transmission of Schistosoma mansoni, the causative agent for human schistosomiasis in the Western hemisphere. For the past two decades, tremendous advances have been made in research aimed at elucidating the molecular basis of the snail/parasite interaction. The growing concern that there is no vaccine to prevent schistosomiasis and only one effective drug in existence provides the impetus to develop new control strategies based on eliminating schistosomes at the snail-stage of the life cycle. To elucidate why a given snail is not always compatible to each and every schistosome it encounters, B. glabrata that are either resistant or susceptible to a given strain of S. mansoni have been employed to track molecular mechanisms governing the snail/schistosome relationship. With such snails, genetic markers for resistance and susceptibility were identified. Additionally, differential gene expression studies have led to the identification of genes that underlie these phenotypes. Lately, the role of schistosomes in mediating non-random relocation of gene loci has been identified for the first time, making B. glabrata a model organism where chromatin regulation by changes in nuclear architecture, known as spatial epigenetics, orchestrated by a major human parasite can now be investigated. This review will highlight the progress that has been made in using molecular approaches to describe snail/schistosome compatibility issues. Uncovering the signaling networks triggered by schistosomes that provide the impulse to turn genes on and off in the snail host, thereby controlling the outcome of infection, could also yield new insights into anti-parasite mechanism(s) that operate in the human host as well. PMID:25101114

  2. Water-collecting behavior of nanostructured surfaces with special wettability

    NASA Astrophysics Data System (ADS)

    Choo, Soyoung; Choi, Hak-Jong; Lee, Heon

    2015-01-01

    Dew is commonly formed even in dry regions, and we examined the suitability of surfaces with superhydrophilic patterns on a superhydrophobic background as a dew-harvesting system. Nanostructured surfaces with mixed wettability were fabricated by ZnO and TiO2 nanorods. The condensation properties were investigated by environmental scanning electron microscopy (ESEM), and the water-collecting function of the patterned surfaces in an artificial environment was confirmed. Condensation and water-collecting behavior were evaluated as a function of surface inclination angle and pattern shape. We examined the collecting efficiency among the different wettabilities at various inclination angles and observed the condensation behavior for various superhydrophilic shapes.

  3. Summary of I-129 measurements in ground and surface waters

    SciTech Connect

    Kantelo, M.V.

    1987-11-17

    The iodine-129 content of groundwater and surface water at on-plant (Savannah River Plant) and off-plant locations has been determined at irregular intervals since 1970 using neutron activation analysis. I-129 was detected in groundwater near the Burial Ground and near the seepage basins of the Separations areas. For reference, I-129 concentrations in the groundwater can be compared to the EPA drinking water standard. At a few locations the concentrations exceeded both the existing and pending EPA drinking water standard. In surface water, Four Mile Creek was the only SRP stream found to transport significant I-129 to the Savannah River. Dilution by C-Reactor discharge and the Savannah River reduced the off-plant I-129 concentrations in river water to less than 1% of the existing EPA drinking water standard and less than 0.01% of the pending EPA drinking water standard.

  4. Two-dimensional percolation at the free water surface and its relation with the surface tension anomaly of water.

    PubMed

    Sega, Marcello; Horvai, George; Jedlovszky, Pál

    2014-08-01

    The percolation temperature of the lateral hydrogen bonding network of the molecules at the free water surface is determined by means of molecular dynamics computer simulation and identification of the truly interfacial molecules analysis for six different water models, including three, four, and five site ones. The results reveal that the lateral percolation temperature coincides with the point where the temperature derivative of the surface tension has a minimum. Hence, the anomalous temperature dependence of the water surface tension is explained by this percolation transition. It is also found that the hydrogen bonding structure of the water surface is largely model-independent at the percolation threshold; the molecules have, on average, 1.90 ± 0.07 hydrogen bonded surface neighbors. The distribution of the molecules according to the number of their hydrogen bonded neighbors at the percolation threshold also agrees very well for all the water models considered. Hydrogen bonding at the water surface can be well described in terms of the random bond percolation model, namely, by the assumptions that (i) every surface water molecule can form up to 3 hydrogen bonds with its lateral neighbors and (ii) the formation of these hydrogen bonds occurs independently from each other. PMID:25106600

  5. Particles in Surface Waters: Coagulation and Transport

    E-print Network

    Culkin, Gerald W.; Lawler, Desmond F.

    -averaged, unsteady particle transport were developed to approximate the size-dependent particle transport processes, which included advection, dispersion, and settling. Coupled exchange of discrete particles between the water column and sediment bed was modeled using...

  6. Detection of Ehrlichia risticii, the Agent of Potomac Horse Fever, in Freshwater Stream Snails (Pleuroceridae: Juga spp.) from Northern California

    PubMed Central

    Barlough, Jeffrey E.; Reubel, Gerhard H.; Madigan, John E.; Vredevoe, Larisa K.; Miller, Paul E.; Rikihisa, Yasuko

    1998-01-01

    Ehrlichia DNA was identified by nested PCR in operculate snails (Pleuroceridae: Juga spp.) collected from stream water in a northern California pasture in which Potomac horse fever (PHF) is enzootic. Sequencing of PCR-amplified DNA from a suite of genes (the 16S rRNA, groESL heat shock operon, 51-kDa major antigen genes) indicated that the source organism closely resembled Ehrlichia risticii, the causative agent of PHF. The minimum percentage of Juga spp. harboring the organism in the population studied was 3.5% (2 of 57 snails). No ehrlichia DNA was found in tissues of 123 lymnaeid, physid, and planorbid snails collected at the same site. These data suggest that pleurocerid stream snails may play a role in the life cycle of E. risticii in northern California. PMID:9687446

  7. Water diffusion on TiO2 anatase surface

    NASA Astrophysics Data System (ADS)

    Agosta, L.; Gala, F.; Zollo, G.

    2015-06-01

    Compatibility between biological molecules and inorganic materials, such as crystalline metal oxides, is strongly dependent on the selectivity properties and the adhesion processes at the interface between the two systems. Among the many different aspects that affect the adsorption processes of peptides or proteins onto inorganic surfaces, such as the charge state of the amino acids, the peptide 3D structure, the surface roughness, the presence of vacancies or defects on and below the surface, a key role is certainly played by the water solvent whose molecules mediate the interaction. Then the surface hydration pattern may strongly affect the adsorption behavior of biological molecules. For the particular case of (101) anatase TiO2 surface that has a fundamental importance in the interaction of biocompatible nano-devices with biological environment, it was shown, both theoretically and experimentally, that various hydration patterns are close in energy and that the water molecules are mobile at as low temperature values as 190 K. Then it is important to understand the dynamical behavior of first hydration layer of the (101) anatase surface. As a first approach to this problem, density functional calculations are used to investigate water diffusion on the (101) anatase TiO2 surface by sampling the potential energy surface of water molecules of the first hydration layer thus calculating the water molecule migration energy along some relevant diffusion paths on the (101) surface. The measured activation energy of water migration seems in contrast with the observed surface mobility of the water molecules that, as a consequence could be explained invoking a strong role of the entropic term in the context of the transition state theory.

  8. Precipitation of salt in saline water drop on superhydrophobic surface

    NASA Astrophysics Data System (ADS)

    Shin, Bongsu; Moon, Myoung-Woon; Kim, Ho-Young

    2012-11-01

    In the membrane distillation process, water vapor of heated, pressurized saline water is transported across the membrane to be collected as pure water. While the water-repellency of the membrane surface has been considered an important parameter affecting the distillation efficiency, the resistance of the membrane to the contamination due to salt has gathered little scientific interest thus far. Here we experimentally investigate the precipitation of salt in sessile saline water drops, to find drastic differences in salt crystallization behavior depending on the water-repellency of solid surface. On a moderately hydrophobic surface with a static contact angle with water being about 150 degrees, salt crystals are aligned and stacked along the initial contact line, forming an interesting structure resembling an igloo. On a superhydrophobic surface with about 164 degrees of static contact angle with water, salt crystallizes only at the center of the drop-solid contact area, forming a pebble-shaped structure. We explain this difference by comparing the evaporation modes (constant contact radius versus constant contact angle) of the sessile drops on those surfaces. We also visualize the liquid flow within drops undergoing evaporation and precipitation at the same time using PIV.

  9. Formation of Water on a Warm Amorphous Silicate Surface

    NASA Astrophysics Data System (ADS)

    Vidali, Gianfranco; He, Jiao

    2014-06-01

    It is well established that reactions on interstellar dust grain surfaces are indispensable for water formation in space. Among all the intermediate products that lead to water formation, the OH radical is especially important because is a product of all the three main water formation surface routes, i.e., the hydrogenation of O, O2, and O3, and it also connects these three routes. The desorption energy of OH from dust grain surfaces, along with dust grain temperature, determines the availability OH for grain surface versus gas-phase reactions. We experimentally investigated water formation on the surface of a warm amorphous silicate via H+O3?OH+O2. The surface temperature was kept at 50 K so as to exclude the interference of O2. It is found that OH has a significant residence time at 50 K. The OH desorption energy from amorphous silicate surface is calculated to be at least 1680 K, and possibly as high as 4760 K. Water is formed efficiently via OH+H and OH+H2, and the product H2O stays on the surface upon formation. Deuterium has also been used in place of hydrogen to check isotopic effects. This work is supported by NSF, Astronomy & Astrophysics Division (Grants No. 0908108 and 1311958) and NASA (Grant No. NNX12AF38G). We thank Dr. J.Brucato of the Astrophysical Observatory of Arcetri for providing the samples used in these experiments.

  10. Salinity adaptation of the invasive New Zealand mud snail (Potamopyrgus antipodarum) in the Columbia River estuary (Pacific Northwest, USA): physiological and molecular studies

    USGS Publications Warehouse

    Hoy, Marshal; Boese, Bruce L.; Taylor, Louise; Reusser, Deborah; Rodriguez, Rusty

    2012-01-01

    In this study, we examine salinity stress tolerances of two populations of the invasive species New Zealand mud snail Potamopyrgus antipodarum, one population from a high salinity environment in the Columbia River estuary and the other from a fresh water lake. In 1996, New Zealand mud snails were discovered in the tidal reaches of the Columbia River estuary that is routinely exposed to salinity at near full seawater concentrations. In contrast, in their native habitat and throughout its spread in the western US, New Zealand mud snails are found only in fresh water ecosystems. Our aim was to determine whether the Columbia River snails have become salt water adapted. Using a modification of the standard amphipod sediment toxicity test, salinity tolerance was tested using a range of concentrations up to undiluted seawater, and the snails were sampled for mortality at daily time points. Our results show that the Columbia River snails were more tolerant of acute salinity stress with the LC50 values averaging 38 and 22 Practical Salinity Units for the Columbia River and freshwater snails, respectively. DNA sequence analysis and morphological comparisons of individuals representing each population indicate that they were all P. antipodarum. These results suggest that this species is salt water adaptable and in addition, this investigation helps elucidate the potential of this aquatic invasive organism to adapt to adverse environmental conditions.

  11. A siphon gage for monitoring surface-water levels

    USGS Publications Warehouse

    McCobb, T.D.; LeBlanc, D.R.; Socolow, R.S.

    1999-01-01

    A device that uses a siphon tube to establish a hydraulic connection between the bottom of an onshore standpipe and a point at the bottom of a water body was designed and tested for monitoring surface-water levels. Water is added to the standpipe to a level sufficient to drive a complete slug of water through the siphoning tube and to flush all air out of the system. The water levels in the standpipe and the water body equilibrate and provide a measurable static water surface in the standpipe. The siphon gage was designed to allow quick and accurate year-round measurements with minimal maintenance. Currently available devices for monitoring surface-water levels commonly involve time-consuming and costly installation and surveying, and the movement of reference points and the presence of ice cover in cold regions cause discontinuity and inaccuracy in the data collected. Installation and field testing of a siphon gage using 0.75-in-diameter polyethylene tubing at Ashumet Pond in Falmouth, Massachusetts, demonstrated that the siphon gage can provide long-term data with a field effort and accuracy equivalent to measurement of ground-water levels at an observation well.A device that uses a siphon tube to establish a hydraulic connection between the bottom of an onshore standpipe and a point at the bottom of a water body was designed and tested for monitoring surface-water levels. Water is added to the standpipe to a level sufficient to drive a complete slug of water through the siphoning tube and to flush all air out of the system. The water levels in the standpipe and the water body equilibrate and provide a measurable static water surface in the standpipe. The siphon gage was designed to allow quick and accurate year-round measurements with minimal maintenance. Currently available devices for monitoring surface-water levels commonly involve time-consuming and costly installation and surveying, and the movement of reference points and the presence of ice cover in cold regions cause discontinuity and inaccuracy in the data collected. Installation and field testing of a siphon gage using 0.75-in-diameter polyethylene tubing at Ashumet Pond in Falmouth, Massachusetts, demonstrated that the siphon gage can provide long-term data with a field effort and accuracy equivalent to measurement of ground-water levels at an observation well.

  12. Passive water control at the surface of a superhydrophobic lichen.

    PubMed

    Hamlett, Christopher A E; Shirtcliffe, Neil James; Pyatt, F Brian; Newton, Michael I; McHale, Glen; Koch, Kerstin

    2011-12-01

    Some lichens have a super-hydrophobic upper surface, which repels water drops, keeping the surface dry but probably preventing water uptake. Spore ejection requires water and is most efficient just after rainfall. This study was carried out to investigate how super-hydrophobic lichens manage water uptake and repellence at their fruiting bodies, or podetia. Drops of water were placed onto separate podetia of Cladonia chlorophaea and observed using optical microscopy and cryo-scanning-electron microscopy (cryo-SEM) techniques to determine the structure of podetia and to visualise their interaction with water droplets. SEM and optical microscopy studies revealed that the surface of the podetia was constructed in a three-level structural hierarchy. By cryo-SEM of water-glycerol droplets placed on the upper part of the podetium, pinning of the droplet to specific, hydrophilic spots (pycnidia/apothecia) was observed. The results suggest a mechanism for water uptake, which is highly sophisticated, using surface wettability to generate a passive response to different types of precipitation in a manner similar to the Namib Desert beetle. This mechanism is likely to be found in other organisms as it offers passive but selective water control. PMID:21785997

  13. Surface Science in the Richmond Lab: Vapor/Water Studies

    E-print Network

    Richmond, Geraldine L.

    , and reactions of gaseous pollutants. These interactions are affected by organics at the water surface, as well and non-polar fluids is an important process for several biological, environmental, pharmaceutical

  14. The biological impact of landfill leachate on nearby surface water

    SciTech Connect

    Geis, S.W. [State Lab. of Hygiene, Madison, WI (United States). Biomonitoring Lab.

    1994-12-31

    Five landfill sites were evaluated for their potential to adversely impact the biotic community of surface waters. Acute and chronic aquatic toxicity tests were used to determine the toxicity of water samples collected from landfill monitoring wells and the nearest surface water. Four of the five landfill sites exhibited acute or chronic toxicity to Ceriodaphnia dubia, Daphnia magna, or Pimephales promelas. Toxicity identification procedures performed on water samples revealed toxic responses to metals and one toxic response to organic compounds. Surface water toxicity at an industrial landfill is most likely due to zinc from a tire production facility. Iron and a surfactant were determined to be the probable causes for toxicity at two municipal solid waste landfills.

  15. Intermolecular Casimir-Polder forces in water and near surfaces

    NASA Astrophysics Data System (ADS)

    Thiyam, Priyadarshini; Persson, Clas; Sernelius, Bo E.; Parsons, Drew F.; Malthe-Sørenssen, Anders; Boström, Mathias

    2014-09-01

    The Casimir-Polder force is an important long-range interaction involved in adsorption and desorption of molecules in fluids. We explore Casimir-Polder interactions between methane molecules in water, and between a molecule in water near SiO2 and hexane surfaces. Inclusion of the finite molecular size in the expression for the Casimir-Polder energy leads to estimates of the dispersion contribution to the binding energies between molecules and between one molecule and a planar surface.

  16. Carbon evasion from surface waters in Alaska

    NASA Astrophysics Data System (ADS)

    Butman, D. E.; Stackpoole, S. M.; Clow, D. W.; Striegl, R. G.; Verdin, K. L.

    2014-12-01

    Gaseous evasion of carbon dioxide and methane from freshwater surfaces has been shown to be upwards of 50% of the total freshwater carbon flux. In many cases, surface efflux is the dominant removal pathway for carbon, however large-scale estimates remain poorly constrained. As part of the ongoing efforts to quantify the carbon sequestration potential of natural ecosystems in the US by the USGS LandCarbon Program, we present the results of a synthesis of available CO2 in streams and rivers, and CO2 and CH4 measurements in lakes across Alaska. For stream carbon, we performed modifications to a synthetic streamline dataset derived from the Elevation Derivatives for National Applications (EDNA) to reflect more recent and accurate climate. Stream and river surface areas only account for 0.54% of the total area of Alaska while preliminary data suggests lakes account for nearly 3.4%. Preliminary analysis suggests 24 Tg-C yr-1 is evaded from fluvial surfaces, with the highest fluxes located in the southeastern region of the state driven by longer periods above freezing, high annual precipitation, and steep topography. We are currently quantifying the uncertainties in these estimates as well as analyzing a new dataset on CO2 and CH4 concentrations in Alaskan lakes. We will present the first estimate for the total freshwater surface carbon flux for Alaska.

  17. Tractor beam on the water surface

    E-print Network

    Punzmann, Horst; Xia, Hua; Falkovich, Gregory; Shats, Michael

    2014-01-01

    Can one send a wave to bring an object from a distance? The general idea is inspired by the recent success in moving micro particles using light and the development of a tractor beam concept. For fluid surfaces, however, the only known paradigm is the Stokes drift model, where linear planar waves push particles in the direction of the wave propagation. Here we show how to fetch a macroscopic floater from a large distance by sending a surface wave towards it. We develop a new method of remote manipulation of floaters by forming inward and outward surface jets, stationary vortices, and other complex surface flows using nonlinear waves generated by a vertically oscillating plunger. The flows can be engineered by changing the geometry and the power of a wave maker, and the flow dissipation. The new method is robust and works both for long gravity and for short capillary waves. We use a novel method of visualising 3D particle trajectories on the surface. This letter introduces a new conceptual framework for unders...

  18. Surface characterization of flax, hemp and cellulose fibers; Surface properties and the water uptake behavior

    Microsoft Academic Search

    Alexander Bismarck; Ibon Aranberri-Askargorta; Thomas Lampke; Bernhard Wielage; Artemis Stamboulis; Ilja Shenderovich; Hans-Heinrich Limbach

    2002-01-01

    The surface characteristics of several natural fibers—flax, hemp and cellulose— were investigated using scanning electron microscopy, BET-surface area and zeta (? -) potential measurements. ? -Potential measurements using the streaming poten- tial method were performed in order to study the water uptake behavior as well as the surface properties of several natural fibers. The influence of different flax-fiber separation methods

  19. Occurrence of deeethylatrazine and deisopropylatrazine in surface and ground water

    SciTech Connect

    Thurman, E.M.; Goolsby, D.A. [US Geological Survey, Lawrence, KS (United States)

    1996-10-01

    Field-disappearance studies and a regional study of nine rivers in the Midwest show that deethylatrazine (DEA) and deisopropylatrazine (DIA) occur frequently in surface water that has received runoff from two parent triazine herbicides, atrazine and cyanazine. The concentration of DEA and DIA in surface water varies with the hydrologic conditions of the basin and the timing of runoff, with maximum concentrations reaching 5 mg/L (DEA + DIA). Early rainfall followed by a dry summer will result in an early peak concentration of metabolites in surface water. A wet summer will delay the maximum concentrations of metabolites and increase their runoff into surface water, occasionally resulting in a slight separation of the parent atrazine maximum concentrations from the metabolite maximum concentrations giving a {open_quotes}second flush{close_quotes} of triazine metabolites to surface water. Replicated field dissipation studies of atrazine and cyanazine indicate that DIA/DEA ratios will vary from 0.4{plus_minus}0.1 when atrazine is the major triazine present to 0.6{plus_minus}0.1 when significant amounts of cyanazine are present. A comparison of transport time of DEA and DIA from field plots to their appearance in surface water indicates that storage and dilution are occurring in the alluvial aquifers of the basin.

  20. Formation and transport of deethylatrazine and deisopropylatrazine in surface water

    USGS Publications Warehouse

    Thurman, E.M.; Meyer, M.T.; Mills, M.S.; Zimmerman, L.R.; Perry, C.A.; Goolsby, D.A.

    1994-01-01

    Field disappearance studies and a regional study of nine rivers in the Midwest Corn Belt show that deethylatrazine (DEA; 2-amino-4-chloro-6-isopropylamino-s-triazine) and deisopropylatrazine (DIA; 2-amino-4-chloro-6-ethylaminos-triazine) occur frequently in surface water that has received runoff from two parent triazine herbicides, atrazine (2-chloro-4-ethylamino-6-isopropylamino-s-triazine) and cyanazine (2-chloro-4-ethylamino-6-methylpropionitrileamino-s-triazine). The concentration of DEA and DIA in surface water varies with the hydrologic conditions of the basin and the timing of runoff, with maximum concentrations reaching 5 ??g/L (DEA + DIA). Early rainfall followed by a dry summer will result in an early peak concentration of metabolites in surface water. A wet summer will delay the maximum concentrations of metabolites and increase their runoff into surface water, occasionally resulting in a slight separation of the parent atrazine maximum concentrations from the metabolite maximum concentrations, giving a "second flush?? of triazine metabolites to surface water. Replicated field dissipation studies of atrazine and cyanazine indicate that DIA/DEA ratios will vary from 0.4 ?? 0.1 when atrazine is the major triazine present to 0.6 ?? 0.1 when significant amounts of cyanazine are present. A comparison of transport time of DEA and DIA from field plots to their appearance in surface water indicates that storage and dilution are occurring in the alluvial aquifers of the basin.

  1. Distribution and speciation of cadmium in the terrestrial snail, Helix aspersa

    Microsoft Academic Search

    Michael Cooke; Andrew Jackson; Graham Nickless; David James Roberts

    1979-01-01

    Conclusions Cadmium is taken up by terrestrial snails living in an environment with a relatively high cadmium concentration. The metal becomes bound to protein with a molecular weight of approximately 22,000 daltons. This cadmium-protein complex concentrates in the digestive gland and is present in a form which is soluble in water, (though difficult to extract efficiently). That no efficient excretion

  2. Behavioural responses of the snail Lymnaea acuminata to carbohydrates in snail-attractant pellets

    NASA Astrophysics Data System (ADS)

    Tiwari, Farindra; Singh, D. K.

    Snail control is one of the most important tools in the campaign to reduce the incidence of fascioliasis. In order to attain this objective, the method of bait formulation in order to contain an attractant and a molluscicide is an expedient approach to lure the target snail population to the molluscicide. This study identifies certain carbohydrates, namely sucrose, maltose, glucose, fructose and starch, for preparing such baits. These were tested on Lymnaea acuminata, an intermediate host of the digenean trematodes Fasciola hepatica and Fasciola gigantica. The behavioural responses of snails to these carbohydrates were examined. Significant variations in behavioural responses were observed in the snail even when the five carbohydrates were used in low concentrations in snail-attractant pellets. Starch emerged as the strongest attractant for Lymnaea acuminata, followed by maltose.

  3. Autonomous Surface Vehicle for Measuring Water Body Parameters

    Microsoft Academic Search

    Joaquín Gutiérrez; Francisco Villa-Medina; M. A. Porta-Gandara

    2010-01-01

    An autonomous surface vehicle (ASV) has been developed to perform autonomous trajectories in protected water bodies for the measurement of diverse parameters. The navigation track is accomplished based on the information from a GPS and an electronic compass. Several water body parameters are measured by means of an electronic sonde. The assigned track is composed by a set of points,

  4. Tritium in surface waters of the Yenisei River basin.

    PubMed

    Bolsunovsky, A Ya; Bondareva, L G

    2003-01-01

    This paper reports an investigation of the tritium content in the surface waters of the Yenisei River basin near the Mining and Chemical Combine (MCC). In 2001 the maximum tritium concentration in the Yenisei River did not exceed 4 +/- 1 Bq l(-1), which is consistent with the data of 1998-99. However, it has been found that there are surface waters containing enhanced tritium as compared with the background values for the Yenisei River. For instance, in the Ploskii Stream and the Shumikha River the maximum tritium concentrations amount to 168 and 81 Bq l(-1), respectively. The source of tritium in these surface waters is the last operating reactor at the MCC, which still uses the Yenisei water as coolant. In water and sediment samples of the Bolshaya Tel River (a tributary of the Yenisei River) the tritium content turned out to be at least 10 times higher than the background values for the Yenisei River. The measurements conducted at the RPA RADON (Moscow) revealed not only tritium but also the artificial radionuclide (14)C in the Bolshaya Tel samples. The data obtained suggest that the Bolshaya Tel River receives the major part of tritium from sediments rather than from the water catchment area. This allows the conclusion that there is water exchange between the surface waters and the radioactively contaminated underground horizons of the "Severny" testing site. PMID:12600760

  5. SARAH2: A NEAR FIELD EXPOSURE ASSESSMENT MODEL FOR SURFACE WATER

    EPA Science Inventory

    The near field surface water model (SARAH2) calculates maximum allowable hazardous waste concentrations, based on predicted exposure to humans or aquatic life from contaminated surface water. The surface water contamination pathways analyzed in SARAH2 include groundwater leachate...

  6. Effect of water table dynamics on land surface hydrologic memory

    Microsoft Academic Search

    Min-Hui Lo; James S. Famiglietti

    2010-01-01

    The representation of groundwater dynamics in land surface models has received considerable attention in recent years. Most studies have found that soil moisture increases after adding a groundwater component because of the additional supply of water to the root zone. However, the effect of groundwater on land surface hydrologic memory (persistence) has not been explored thoroughly. In this study we

  7. Evidence for the Exposure of Water Ice on Titan's Surface

    E-print Network

    Griffith, Caitlin A.

    Evidence for the Exposure of Water Ice on Titan's Surface Caitlin A. Griffith,1 * Tobias Owen,2 Thomas R. Geballe,3 John Rayner,2 Pascal Rannou4 The smoggy stratosphere of Saturn's largest moon, Titan.0, 2.9, and 5.0 micrometers. We derived a spectrum of Titan's surface within these "windows

  8. Tritium in surface waters of the Yenisei River basin

    Microsoft Academic Search

    A. Ya. Bolsunovsky; L. G. Bondareva

    2003-01-01

    This paper reports an investigation of the tritium content in the surface waters of the Yenisei River basin near the Mining and Chemical Combine (MCC). In 2001 the maximum tritium concentration in the Yenisei River did not exceed 4 ± 1 Bq l–1, which is consistent with the data of 1998–99. However, it has been found that there are surface

  9. Quality of surface water in Missouri, water year 2009

    USGS Publications Warehouse

    Barr, Miya N.

    2010-01-01

    The U.S. Geological Survey, in cooperation with the Missouri Department of Natural Resources, designs and operates a series of monitoring stations on streams throughout Missouri known as the Ambient Water-Quality Monitoring Network. During the 2009 water year (October 1, 2008, through September 30, 2009), data were collected at 75 stations-69 Ambient Water-Quality Monitoring Network stations, 2 U.S. Geological Survey National Stream Quality Accounting Network stations, 1 spring sampled in cooperation with the U.S. Forest Service, and 3 stations sampled in cooperation with the Elk River Watershed Improvement Association. Dissolved oxygen, specific conductance, water temperature, suspended solids, suspended sediment, fecal coliform bacteria, Escherichia coli bacteria, dissolved nitrate plus nitrite, total phosphorus, dissolved and total recoverable lead and zinc, and select pesticide compound summaries are presented for 72 of these stations. The stations primarily have been classified into groups corresponding to the physiography of the State, primary land use, or unique station types. In addition, a summary of hydrologic conditions in the State including peak discharges, monthly mean discharges, and seven-day low flow is presented.

  10. 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.

  11. Mobility of Water on Oxide Surfaces Studied by QENS

    SciTech Connect

    Mamontov, Eugene [ORNL

    2007-01-01

    Although neutron scattering is often considered a bulk probe, we demonstrate that the mobility of surface water on oxide nano-powders can be investigated using quasielastic neutron scattering. We discuss how the reduced number of hydrogen bonds per water molecule associated with surface confinement leads to a qualitative modification of single-particle translational dynamics compared to bulk water. The mobility of surface water in zirconium oxide with two hydration layers present is discussed in detail. The outer hydration layer exhibits translational dynamics on the time scale of tens of picoseconds, and thus can be studied using time-of-flight neutron spectrometry. The translational dynamics of the inner hydration layer in the range of hundreds of picoseconds can be assessed with backscattering neutron spectrometry. Interestingly, despite being slower by two orders of magnitude, the translational motion of the molecules of the inner hydration layer may share more common traits with bulk water compared to the motion of the outer hydration layer, the dynamics of which is slower than that of bulk water by just one order of magnitude. Similar to bulk water, the temperature dependence of the residence time for the water molecules of the inner hydration layer is non-Arrhenius, and can be described by a Vogel-Fulcher-Tammann (VFT) law. On the other hand, the molecules of the outer hydration layer demonstrate Arrhenius-type temperature dependence indicative of thermally activated surface jump diffusion. Our recent study of surface water on cerium oxide, which exhibits faster dynamics compared to water on zirconium oxide, has ventured into the low-temperature region (down to 200 K). Below 215 K, we have found a deviation from the VFT temperature dependence for the residence time indicative of a surprise "fragile"-to-"strong" transition in the surface water. While "fragile"-to-"strong" transition has been predicted in supercooled bulk water, there has been no prediction of such a transition in surface water. We discuss the links between our results and recent work on hydration water in carbon nanotubes and proteins.

  12. An Ontology Design Pattern for Surface Water Features

    SciTech Connect

    Sinha, Gaurav [Ohio University, Athens; Mark, David [University at Buffalo, NY; Kolas, Dave [Raytheon BBN Technologies; Varanka, Dalia [U.S. Geological Survey, Rolla, MO; Romero, Boleslo E [University of California, Santa Barbara; Feng, Chen-Chieh [National University of Singapore; Usery, Lynn [U.S. Geological Survey, Rolla, MO; Liebermann, Joshua [Tumbling Walls, LLC; Sorokine, Alexandre [ORNL

    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 can be found 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. It can then be used to systematically incor-porate concepts that are specific to a culture, language, or scientific domain. The Surface Water ontology design pattern was developed both for domain knowledge distillation and to serve as a conceptual building-block for more complex surface water ontologies. A fundamental distinction is made in this on-tology 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 imple-mented in OWL, but Description Logic axioms and a detailed explanation is provided. The OWL ontology will be an important contribution to Semantic Web vocabulary for annotating surface water feature datasets. A discussion about why there is a need to complement the pattern with other ontologies, es-pecially the previously developed Surface Network pattern is also provided. Fi-nally, the practical value of the pattern in semantic querying of surface water datasets is illustrated through a few queries and annotated geospatial datasets.

  13. 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.

  14. Nucleate boiling of water from plain and structured surfaces

    SciTech Connect

    Das, A.K.; Das, P.K.; Saha, P. [Department of Mechanical Engineering, Indian Institute of Technology, Kharagpur 721302 (India)

    2007-08-15

    Heat transfer from plain surface and from surfaces with distinct nucleation sites has been investigated under saturated pool boiling condition. Surfaces have been prepared with regular array of discrete nucleation sites formed by micro-drilling. Distilled water has been used as the boiling liquid. Out of various available correlations, Rohsenow correlation [W.M. Rohsenow, A method of correlating heat transfer data for surface boiling of liquids, Trans. ASME 74 (1952) 969-976] gives best agreement with the experimental data from plain surface at low degree of superheat. A mechanistic model also provides a good trend matching with the same experimental data. With the introduction of artificial nucleation sites substantial augmentation in heat transfer for distilled water compared to the plane surface has been noted. Continuous increase in nucleation site density increases the rate of heat transfer with a diminishing trend of enhancement. A correlation similar to that of Yamagata et al. [K. Yamagata, F. Hirano, K. Nishiwaka, H. Matsouka, Nucleate boiling of water on the horizontal heating surface, Mem. Fac. Eng. Kyushu 15 (1955) 98] has been developed to fit the experimental data of plane surface. Modification of the same correlation to take care of the nucleation site density has been developed and used to predict the experimental data from augmented surfaces. (author)

  15. DETECTION OF A GROUND-WATER/SURFACE-WATER INTERFACE WITH DIRECT-PUSH EQUIPMENT

    EPA Science Inventory

    A ground-water/surface-water interface (GSI) was documented at the Thermo Chem CERCLA Site in Muskegon, MI via direct-push (DP) sampling. At that time, contaminated ground water flowed from the upland area of the site into the Black Creek floodplain. DP rods equipped with a 1.5...

  16. MONITORING OXIDATION-REDUCTION PROCESS DURING GROUND WATER-SURFACE WATER INTERACTIONS AT THE CHICKASAW NRA

    EPA Science Inventory

    Mineralized ground waters at the Chickasaw National Recreational Area contain hydrogen sulfide, i.e., sulfur in the -2 valence state. As these mineralized ground waters discharge at the surface and mix with oxygen-rich waters a series of abiotic and biotic reactions occur that c...

  17. Surface water data at Los Alamos National Laboratory: 1996 water year. Progress report

    SciTech Connect

    Shaull, D.A.; Alexander, M.R.; Reynolds, R.P.; McLean, C.T.

    1996-11-01

    The principle investigators collected and computed surface water discharge data from 17 stream-gaging stations that cover most of Los Alamos National Laboratory. The data show less runoff than do data for the 1995 water year. Water chemistry data from larger storm events occurring at some stations are also published here.

  18. Improving water quality in polluated drains with free water surface constructed wetlands

    Microsoft Academic Search

    Mahmoud A. El-Sheikh; Hazem I. Saleh; Diaa E. El-Quosy; Abdallah A. Mahmoud

    2010-01-01

    In Egypt, disposing of partially treated or untreated domestic and industrial wastewater into agricultural drains deteriorates their water quality. A growing interest in effective low-cost treatment of polluted water and wastewater has resulted in many studies on constructed wetlands.This study evaluates free water surface constructed wetlands (by far the largest application project is named “Lake Manzala Engineered Wetland [Egypt]”) utilized

  19. Particles in Surface Waters: Coagulation and Transport.

    NASA Astrophysics Data System (ADS)

    Culkin, Gerald William

    Conventional water quality assessment and simulation of particles in natural waters focus on bulk concentrations of the suspended solid phase. These analyses rely directly or indirectly on a linear, 'average particle' approach to describe processes that are nonlinear and highly size -dependent. Size-dependent transport and transformation mechanisms were simulated in this research to identify conditions in which coagulation is important. Explicit finite difference schemes for two-dimensional, laterally-averaged, unsteady particle transport were developed to approximate the size -dependent particle transport processes, which included advection, dispersion, and settling. Coupled exchange of discrete particles between the water column and sediment bed was modeled using size-dependent particle sedimentation and resuspension. Simultaneous particle-particle flocculation was integrated over time in parallel with transport. Model simulations of systems with idealized morphometry and forcing provided greater insight to competing processes that drive particle behavior in natural systems. Application of the model to a real system gave plausible results and suggested explanations for observed conditions.

  20. 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. PMID:25893132

  1. Tracer injection techniques in flowing surface water

    NASA Astrophysics Data System (ADS)

    Wörman, A.

    2009-04-01

    Residence time distributions for flowing water and reactive matter are commonly used integrated properties of the transport process for determining technical issues of water resource management and in eco-hydrological science. Two general issues for tracer techniques are that the concentration-vs-time relation following a tracer injection (the breakthrough curve) gives unique transport information in different parts of the curve and separation of hydromechanical and reactive mechanisms often require simultaneous tracer injections. This presentation discusses evaluation methods for simultaneous tracer injections based on examples of tracer experiments in small rivers, streams and wetlands. Tritiated water is used as a practically inert substance to reflect the actual hydrodynamics, but other involved tracers are Cr(III)-51, P-32 and N-15. Hydromechanical, in-stream dispersion is reflected as a symmetrical spreading of the spatial concentration distribution. This requires that the transport distance over water depth is larger than about five times the flow Peclet number. Transversal retention of both inert and reactive solutes is reflected in terms of the tail of the breakthrough curve. Especially, reactive solutes can have a substantial magnification of the tailing behaviour depending on reaction rates or partitioning coefficients. To accurately discriminate between the effects of reactions and hydromechanical mixing its is relevant to use simultaneous injections of inert and reactive tracers with a sequential or integrated evaluation procedure. As an example, the slope of the P-32 tailing is consistently smaller than that of a simultaneous tritium injection in Ekeby wetland, Eskilstuna. The same applies to N-15 injected in the same experiment, but nitrogen is affected also by a systematic loss due to denitrification. Uptake in stream-bed sediments can be caused by a pumping effect arising when a variable pressure field is created on the stream bottom due to bed irregularities. The so-called pumping model provided good estimates of the storage in the hyporheic zone under different stream discharges and stream flow conditions along streams. Evaluations Hobøl River, Norway, and Säva Brook, Sweden, at two occasions in both stream indicate that the relative residence time in the hyporheic zone is linearly proportional to the squared Froude Number. The residence time is scaled with water depth and hydraulic conductivity of the bed. The effect of such transient storage in e.g. the hyporheic zone gives rise to a tailing, but the breakthrough curve become increasingly symmetrical with Damköhler number. Such a symmetrical breakthrough can be erroneously taken as an effect of in-stream dispersion, even though this similarity is merely due to the physical analogy of various advection velocities over the transport cross-section, differential advection.

  2. Experimental water droplet impingement data on modern aircraft surfaces

    NASA Technical Reports Server (NTRS)

    Papadakis, Michael; Breer, Marlin D.; Craig, Neil C.; Bidwell, Colin S.

    1991-01-01

    An experimental method has been developed to determine the water droplet impingement characteristics on two- and three-dimensional aircraft surfaces. The experimental water droplet impingement data are used to validate particle trajectory analysis codes that are used in aircraft icing analyses and engine inlet particle separator analyses. The aircraft surface is covered with thin strips of blotter paper in areas of interest. The surface is then exposed to an airstream that contains a dyed-water spray cloud. The water droplet impingement data are extracted from the dyed blotter paper strips by measuring the optical reflectance of each strip with an automated reflectometer. Preliminary experimental and analytical impingement efficiency data are presented for a NLF(1)-0414F airfoil, s swept MS(1)-0317 airfoil, a swept NACA 0012 wingtip and for a Boeing 737-300 engine inlet model.

  3. Index of surface-water stations in Texas, January 1988

    USGS Publications Warehouse

    Carrillo, E. R., (compiler); Buckner, H.D.; Rawson, Jack

    1988-01-01

    As of January 1, 1988, the surface water data collection network in Texas included 368 continuous streamflow, 72 continuous or daily reservoir-contents, 38 gage height only, 15 crest stage partial record, 4 periodic discharge through range, 32 flood-hydrograph partial-record, 9 flood-profile partial-record, 36 low-flow partial record, 45 daily chemical-quality, 19 lake surveys, 160 periodic organic and (or) nutrient, 3 periodic insecticide, 33 periodic pesticide, 20 automatic sampler, 137 periodic minor elements, 125 periodic chemical-quality, 74 periodic physical-organic, 24 continuous-recording three- or four-parameter water quality, 34 periodic sediment, 21 continuous-recording temperature, and 30 national stream-quality accounting network stations. Plate 1 shows the location of surface water streamflow or reservoir content and chemical quality or sediment stations in Texas. Plate 2 shows the location of partial-record surface-water stations. (USGS)

  4. Index of surface-water stations in Texas, January 1989

    USGS Publications Warehouse

    Rawson, Jack, (compiler); Carrillo, E.R.; Buckner, H.D.

    1989-01-01

    As of January 1, 1989, the surface-water data-collection network in Texas included 373 continuous-streamflow, 75 continuous or daily reservoir-content, 37 gage-height, 15 crest-stage partial-record, 200 data collection platform, 7 periodic discharge through range, 27 flood-hydrograph partial-record, 27 low-flow partial-record, 43 daily chemical-quality, 17 continuous-recording water quality, 87 periodic biological, 11 lake survey, 159 period organic and (or) nutrient, 2 periodic insecticide, 28 periodic pesticide, 19 automatic sampler, 137 periodic minor element, 126 periodic chemical-quality, 75 periodic physical organic, 17 continuous-recording temperature, and 29 national stream-gaging accounting network stations. Plate 1 shows the location of surface-water streamflow or reservoir-content and chemical-quality or sediment stations in Texas. Plate 2 shows the location of partial-record surface-water stations. (USGS)

  5. Circumnutation on the water surface: female flowers of Vallisneria

    PubMed Central

    Kosuge, Keiko; Iida, Satoko; Katou, Kiyoshi; Mimura, Tetsuro

    2013-01-01

    Circumnutation, the helical movement of growing organ tips, is ubiquitous in land plants. The mechanisms underlying circumnutation have been debated since Darwin's time. Experiments in space and mutant analyses have revealed that internal oscillatory (tropism-independent) movement and gravitropic response are involved in circumnutation. Female flower buds of tape grass (Vallisneria asiatica var. biwaensis) circumnutate on the water surface. Our observations and experiments with an artificial model indicated that gravitropism is barely involved in circumnutation. Instead, we show that helical intercalary growth at the base of peduncle plays the primary role in all movements in Vallisneria. This growth pattern produces torsional bud rotation, and gravity and buoyancy forces have a physical effect on the direction of peduncle elongation, resulting in bud circumnutation on the water surface. In contrast to other water-pollinated hydrophilous plants, circumnutation in Vallisneria enables female flowers to actively collect male flowers from a larger surface area of water. PMID:23355948

  6. Shape-gradient composite surfaces: water droplets move uphill.

    PubMed

    Zhang, Jilin; Han, Yanchun

    2007-05-22

    The approach of water droplets self-running horizontally and uphill without any other forces was proposed by patterning the shape-gradient hydrophilic material (i.e., mica) to the hydrophobic matrix (i.e., wax or low-density polyethylene (LDPE)). The shape-gradient composite surface is the best one to drive water droplet self-running both at the high velocity and the maximal distance among four different geometrical mica/wax composite surfaces. The driving force for the water droplets self-running includes: (1) the great difference in wettability of surface materials, (2) the low contact angle hysteresis of surface materials, and (3) the space limitation of the shape-gradient transportation area. Furthermore, the average velocity and the maximal distance of the self-running were mainly determined by the gradient angle (alpha), the droplet volume, and the difference of the contact angle hysteresis. Theoretical analysis is in agreement with the experimental results. PMID:17444664

  7. [Current status of surface water acidification in Northeast China].

    PubMed

    Xu, Guang-yi; Kang, Rong-hua; Luo, Yao; Duan, Lei

    2013-05-01

    In order to evaluate the status of surface water acidification in Northeast China, chemical composition of 33 small streams was investigated in August, 2011. It was found that only a few waters located in Changbai Mountain had pH of lower than 6.0, and all waters had acid neutralizing capacity (ANC) of higher than 0.2 meq x L(-1). This indicated that surface water acidification was not a regional environmental issue in Northeast China. HCO3- was the major anion, with SO4(2-) concentration mostly below 150 microeq x L(-1) and even much lower NO3- concentration. Low concentration of SO4(2-) and NO3- means no serious acid deposition in this area. However, the distribution of acidic forest soils, with low base cation weathering rate, could only provide limited buffering capacity for surface water to acidification in Northeast China, and the potential risk of water acidification still existed. Currently, acid deposition in Northeast Asia could hardly cause severe acidification of surface water. The neighboring countries should therefore not amplify the environmental impact by transboundary air pollutants from China. PMID:23914517

  8. Time dependence of forces between mica surfaces in water and its relation to the release of surface ions

    E-print Network

    Klein, Jacob

    Time dependence of forces between mica surfaces in water and its relation to the release of surface between two smooth mica surfaces immersed in salt-free conductivity water. A long-ranged repulsion of K ions from the mica surface into the water. Subsequent force measurements at times following

  9. 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.

  10. Estimation of precipitable water from surface observations 

    E-print Network

    Kahan, Archie Marion

    1959-01-01

    Solar Cell. It so happens that the peak of response of this ce ll is c lose to the center of the water vapor absorption band (935 m illim icrons), the band best suited for use in determining absorptions of the order found in sunlight passing... ce ll is in the green portion of the v isible spectrum at a wavelength o f 0. 52 m icrons. Sensitivity at 0. 55 m icrons is 1 per cent of that at 0. 52 m icrons. The spectral response of this cell is shown in Figure 5. Because of the sharp...

  11. Surface water pesticide modelling for decision support in drinking water production

    NASA Astrophysics Data System (ADS)

    Desmet, Nele; Dams, Jef; Bronders, Jan; Peleman, Gisèle; Verdickt, Liesbeth

    2015-04-01

    The occurrence of pesticides and other contaminants in river systems may compromise the use of surface water for drinking water production. To reduce the cost of removal of pesticides from the raw water, drinking water companies can: search for other raw water sources, invest in water storage capacity to overcome periods with high pesticide concentrations (often related to the application period), or impose measures to reduce the emission of pesticides to surface water (i.e. sustainable application strategies or use restrictions). To select the most appropriate water management options, the costs and effects of the aforementioned actions need to be evaluated. This evaluation requires knowledge on the concentrations and loads of pesticides at the point of drinking water abstraction, as well as insight in the contribution and the temporal variability of different sources or subbasins. In such a case, a modelling approach can assist in generating measurement-based datasets and to compare different scenarios for water management. We illustrate how a modelling approach can provide decision support for water management related to drinking water abstraction from surface water in a catchment that suffers from elevated pesticide concentrations. The study area is a water production center (WPC) located in northwestern Belgium. The WPC abstracts raw water from the river IJzer or from a natural pond and its connected streams. The available quantities as well as the quality of the water vary throughout the year. The WPC uses a reservoir of 3 million m³ to capture and store raw water to overcome periods with limited water availability and/or poor water quality. However, the pressure on water increases and in the future this buffering capacity might be no longer sufficient to fulfill the drinking water production demand. A surface water quality model for the area is set up using InfoWorks RS. The model is applied to obtain insight in the concentrations and loads at the different points of drinking water abstraction (river IJzer and Blankaart pond), the contribution of the subbasins, and the seasonal dynamics. The model is also applied for scenario analysis related to water management and varying climatological conditions. Especially in summer, the availability of raw water of good quality for the WPC is limited. The discharge of the river IJzer is low and a minimum level is required for navigation, and the pond is part of a nature reserve where a minimum water level is imposed for conservation of aquatic habitats, and application of pesticides on the surrounding agricultural lands results in high pesticide concentrations (e.g. bentazon > 1µg/L).

  12. Snail–periphyton interactions in a prairie lacustrine wetland

    Microsoft Academic Search

    B. J. Hann; C. J. Mundy; L. G. Goldsborough

    2001-01-01

    This study examined the effects of nutrients and macrophytes on snail grazers and periphyton in a prairie wetland food web. Snails (Gyraulus circumstriatus) and periphyton in large enclosures in a lacustrine wetland, Delta Marsh, MB, Canada were subjected to two experimental treatments, nutrient addition (nitrogen, phosphorus) and macrophyte exclusion (using a porous geotextile carpet) during July and August. Snail biomass

  13. Snail-periphyton interactions in a prairie lacustrine wetland

    Microsoft Academic Search

    B. J. Hann; C. J. Mundy; L. G. Goldsborough

    2001-01-01

    This study examined the effects of nutrients and macrophytes on snail grazers and periphyton in a prairie wetland food web. Snails (Gyraulus circumstriatus) and periphyton in large enclosures in a lacustrine wetland, Delta Marsh, MB, Canada were subjected to two experimental treatments, nutrient addition (nitrogen, phosphorus) and macrophyte exclusion (using a porous geotextile carpet) during July and August. Snail biomass

  14. Snail populations in arctic lakes: competition mediated by predation?

    Microsoft Academic Search

    Anne E. Hershey

    1990-01-01

    For 2 species of snails in arctic Alaskan lakes, I studied the patterns of snail distribution with respect to habitat, distribution of predatory fish, and the potential for interspecific competition. The snails Lymnaea elodes and Valvata lewisi co-exist in these arctic lakes, either in the presence of lake trout, Salvelinus namaycush, or in the absence of predation. Intensive sediment core

  15. Images of Minute Minnesota Land Snails Matt Barthel

    E-print Network

    Nekola, Jeffrey C.

    Images of Minute Minnesota Land Snails Matt Barthel January 2000 This disk contains diagnostic images representative of minute land snail taxa from Minnesota. The snails imaged are from throughout at the University of Wisconsin-Green Bay (UWGB). The shells imaged were assigned to species (or subspecies) based

  16. Experimental Values of the Surface Tension of Supercooled Water

    NASA Technical Reports Server (NTRS)

    Hacker, P. T.

    1951-01-01

    The results of surface-tension measurements for supercooled water are presented. A total of 702 individual measurements of surface tension of triple-distilled water were made in the temperature range, 27 to -22.2 C, with 404 of these measurements at temperatures below 0 C. The increase in magnitude of surface tension with decreasing temperature, as indicated by measurements above 0 C, continues to -22.2 C. The inflection point in the surface-tension - temperature relation in the vicinity of 0 C, as indicated by the International Critical Table values for temperatures down to -8 C, is substantiated by the measurements in the temperature range, 0 to -22.2 C. The surface tension increases at approximately a linear rate from a value of 76.96+/-0.06 dynes per centimeter at -8 C to 79.67+/-0.06 dynes per centimeter at -22.2 C.

  17. Experimental observation of dark solitons on the surface of water.

    PubMed

    Chabchoub, A; Kimmoun, O; Branger, H; Hoffmann, N; Proment, D; Onorato, M; Akhmediev, N

    2013-03-22

    We present the first ever observation of dark solitons on the surface of water. It takes the form of an amplitude drop of the carrier wave which does not change shape in propagation. The shape and width of the soliton depend on the water depth, carrier frequency, and the amplitude of the background wave. The experimental data taken in a water tank show an excellent agreement with the theory. These results may improve our understanding of the nonlinear dynamics of water waves at finite depths. PMID:25166807

  18. Surface water resources issues analysis: Wheeler Reservoir watershed region

    SciTech Connect

    Cox, J.P.

    1990-02-01

    This report is one in a continuing series of periodic water resources issues analyses (WRIAs) conducted within the various local drainage basins that comprise the larger Tennessee River drainage basin. These analyses, based primarily upon existing information gathered from a variety of sources, perform several functions: document known or probable water quality issues that should be addressed by TVA or others; identify specific needs for additional information; guide routine surface water monitoring programs; and provide focus for planning and setting priorities for subsequent water quality assessments, mitigative activities, and resource management projects. 4 refs., 1 fig., 16 tabs.

  19. Hydroeconomic optimization of integrated water management and transfers under stochastic surface water supply

    NASA Astrophysics Data System (ADS)

    Zhu, Tingju; Marques, Guilherme Fernandes; Lund, Jay R.

    2015-05-01

    Efficient reallocation and conjunctive operation of existing water supplies is gaining importance as demands grow, competitions among users intensify, and new supplies become more costly. This paper analyzes the roles and benefits of conjunctive use of surface water and groundwater and market-based water transfers in an integrated regional water system where agricultural and urban water users coordinate supply and demand management based on supply reliability and economic values of water. Agricultural users optimize land and water use for annual and perennial crops to maximize farm income, while urban users choose short-term and long-term water conservation actions to maintain reliability and minimize costs. The temporal order of these decisions is represented in a two-stage optimization that maximizes the net expected benefits of crop production, urban conservation and water management including conjunctive use and water transfers. Long-term decisions are in the first stage and short-term decisions are in a second stage based on probabilities of water availability events. Analytical and numerical analyses are made. Results show that conjunctive use and water transfers can substantially stabilize farmer's income and reduce system costs by reducing expensive urban water conservation or construction. Water transfers can equalize marginal values of water across users, while conjunctive use minimizes water marginal value differences in time. Model results are useful for exploring the integration of different water demands and supplies through water transfers, conjunctive use, and conservation, providing valuable insights for improving system management.

  20. Modeling decadal timescale interactions between surface water and ground water in the central Everglades, Florida, USA

    USGS Publications Warehouse

    Harvey, J.W.; Newlin, J.T.; Krupa, S.L.

    2006-01-01

    Surface-water and ground-water flow are coupled in the central Everglades, although the remoteness of this system has hindered many previous attempts to quantify interactions between surface water and ground water. We modeled flow through a 43,000 ha basin in the central Everglades called Water Conservation Area 2A. The purpose of the model was to quantify recharge and discharge in the basin's vast interior areas. The presence and distribution of tritium in ground water was the principal constraint on the modeling, based on measurements in 25 research wells ranging in depth from 2 to 37 m. In addition to average characteristics of surface-water flow, the model parameters included depth of the layer of 'interactive' ground water that is actively exchanged with surface water, average residence time of interactive ground water, and the associated recharge and discharge fluxes across the wetland ground surface. Results indicated that only a relatively thin (8 m) layer of the 60 m deep surfical aquifer actively exchanges surface water and ground water on a decadal timescale. The calculated storage depth of interactive ground water was 3.1 m after adjustment for the porosity of peat and sandy limestone. Modeling of the tritium data yielded an average residence time of 90 years in interactive ground water, with associated recharge and discharge fluxes equal to 0.01 cm d -1. 3H/3He isotopic ratio measurements (which correct for effects of vertical mixing in the aquifer with deeper, tritium-dead water) were available from several wells, and these indicated an average residence time of 25 years, suggesting that residence time was overestimated using tritium measurements alone. Indeed, both residence time and storage depth would be expected to be overestimated due to vertical mixing. The estimate of recharge and discharge (0.01 cm d-1) that resulted from tritium modeling therefore is still considered reliable, because the ratio of residence time and storage depth (used to calculated recharge and discharge) is much less sensitive to vertical mixing compared with residence time alone. We conclude that a small but potentially significant component of flow through the Everglades is recharged to the aquifer and stored there for years to decades before discharged back to surface water. Long-term storage of water and solutes in the ground-water system beneath the wetlands has implications for restoration of Everglades water quality.

  1. A Mechanism for Near-Surface Water Ice on Mars

    NASA Astrophysics Data System (ADS)

    Travis, B. J.; Feldman, W. C.; Maurice, S.

    2009-12-01

    Recent findings (e.g., Byrne et al, 2009) indicate that water ice lies very close to the surface at mid-latitudes on Mars. Re-interpretation of neutron and gamma-ray data is consistent with water ice buried less than a meter or two below the surface. Hydrothermal convection of brines provides a mechanism for delivering water to the near-surface. Previous numerical and experimental studies with pure water have indicated that hydrothermal circulation of pore water should be possible, given reasonable estimates of geothermal heat flux and regolith permeability. For pure water convection, the upper limit of the liquid zone would lie at some depth, but in the case of salt solutions, the boundary between liquid and frozen pore water could reach virtually to the surface. The principal drivers for hydrothermal circulation are regolith permeability, geothermal heat flux, surface temperature and salt composition. Both the Clifford and the Hanna-Phillips models of Martian regolith permeability predict sufficiently high permeabilities to sustain hydrothermal convection. Salts in solution will concentrate in upwelling plumes as the cold surface is approached. As water ice is excluded upon freezing, the remaining solution becomes a more concentrated brine, reaching its eutectic concentration before freezing. Numerical simulations considering several salts (NaCl, CaCl2, MgSO4), and a range of heat fluxes (20 - 100 mW/m2) covering the range of estimated present day heat flux (20 to 40 mW/m2) to moderately elevated conditions (60 to 100 mW/m2) such as might exist in the vicinity of volcanoes and craters, all indicate the same qualitative behavior. A completely liquid, convective regime occurs at depth, overlain by a partially frozen "mushy" layer (but still convecting despite the increased viscosity), overlain by a thin frozen layer at the surface. The thicknesses of these layers depend on the heat flux, surface temperature and the salt. As heat flux increases, the mushy region lies closer and closer to the surface, and the frozen layer thins. At the higher heat fluxes (> 60 mW/m2), upwelling plumes can deliver liquid brine to within a few meters of the surface, even breaching it for the salts with very low eutectic points.

  2. Reaction of water vapor with a clean liquid uranium surface

    SciTech Connect

    Siekhaus, W.

    1985-10-24

    To study the reaction of water vapor with uranium, we have exposed clean liquid uranium surfaces to H/sub 2/O under UHV conditions. We have measured the surface concentration of oxygen as a function of exposure, and determined the maximum attainable surface oxygen concentration X/sub 0//sup s/ as a function of temperature. We have used these measurements to estimate, close to the melting point, the solubility of oxygen (X/sub 0//sup b/, < 10/sup -4/) and its surface segregation coefficient ..beta../sup s/(> 10/sup 3/). 8 refs., 5 figs., 1 tab.

  3. Integrated Land Surface Water State Indicators for Climate Assessment

    NASA Astrophysics Data System (ADS)

    Lamb, B. T.; McDonald, K. C.; Steiner, N.; Azarderakhsh, M.; Schroeder, R.

    2014-12-01

    Accurate characterization of seasonal freeze/thaw transition timing coupled with accompanying characterization of snowpack water content, surface inundation, and radiation balance give the potential for an unambiguous indication of climate change. Earth remote sensing data sources have demonstrated utility for determining these surface and radiation balance state variables. NASA's Climate Indicators Team seeks to develop and test potential climate indicators that employ NASA capabilities to support the National Climate Assessemnt and are useful to decision makers. We present development of a set of climate indicators built upon remote sensing measures of surface water state variables: Landscape freeze/thaw (FT), Snow Water Equivalent (SWE), Surface inundation fraction (Fw), and radiative flux. Indicators based on and derived from these parameters may be assembled from integrated remote sensing datasets and provide key information in assessment of climate state. Combined, these state variables provide unique insight into linkages and feedbacks in terrestrial energy, water and carbon cycles and allow examination to the response of the integrated system to climate drivers. Assembled from existing remote sensing datasets, these deliverables will represent the first broad-scale observationally-based, comprehensive measures of surface water state and distribution coupled to atmospheric radiation for use in climate change assessment.

  4. First-principles study of water on Cu (110) surface

    NASA Astrophysics Data System (ADS)

    Ren, Jun; Meng, Sheng

    2009-03-01

    The persistent demand for cheaper and high efficient catalysts in industrial chemical synthesis, such as ammonia, and in novel energy applications, hydrogen generation and purification in fuel cells motivated us to study the fundamental interaction involved in water-Cu system, with an intension to examine Cu as a possible competitive candidate for cheaper catalysts. Water structure and dissociation kinetics on a model open metal surface: Cu (110), have been investigated in detail based on first-principles electronic structure calculations. We revealed that in both monomer and overlayer forms, water adsorbs molecularly, with a high tendency for diffusion and/or desorption rather than dissociation on clean surfaces at low temperature. With the increase of the water coverage on the Cu (110) surface, the H-bond pattern lowers the dissociation barrier efficiently. More importantly, if the water molecule is dissociated, the hydrogen atoms can diffuse freely along the [110] direction, which is very useful in the hydrogen collection. In addition, we extended to study water on other noble metal (110) surfaces. The result confirms that Cu (110) is the borderline between intact and dissociative adsorption, differing in energy by only 0.08 eV. This may lead to promising applications in hydrogen generation and fuel cells.

  5. Dark solitons on the surface of water

    NASA Astrophysics Data System (ADS)

    Chabchoub, Amin

    2014-05-01

    The nonlinear Schrödinger equation (NLS) models the evolution dynamics in time and space of weakly nonlinear water wave trains in finite or infinite depth. In the defocusing regime (finite depth), the NLS admits a family of soliton solutions, which describe the strong depression of wave envelopes. These solitons are referred to dark solitons and have been already observed in optics and in Bose-Einstein condensates. We present experimental results on gray and black solitons, propagating in a wave flume. Furthermore, we analyze the data and discuss the discrepancies observed with respect to theoretical predictions. The results prove that in the case of weak-nonlinearity of the waves, the NLS describes well the dynamics of nonlinear wave packets in finite depth.

  6. Differential spatial repositioning of activated genes in Biomphalaria glabrata snails infected with Schistosoma mansoni.

    PubMed

    Arican-Goktas, Halime D; Ittiprasert, Wannaporn; Bridger, Joanna M; Knight, Matty

    2014-09-01

    Schistosomiasis is an infectious disease infecting mammals as the definitive host and fresh water snails as the intermediate host. Understanding the molecular and biochemical relationship between the causative schistosome parasite and its hosts will be key to understanding and ultimately treating and/or eradicating the disease. There is increasing evidence that pathogens that have co-evolved with their hosts can manipulate their hosts' behaviour at various levels to augment an infection. Bacteria, for example, can induce beneficial chromatin remodelling of the host genome. We have previously shown in vitro that Biomphalaria glabrata embryonic cells co-cultured with schistosome miracidia display genes changing their nuclear location and becoming up-regulated. This also happens in vivo in live intact snails, where early exposure to miracidia also elicits non-random repositioning of genes. We reveal differences in the nuclear repositioning between the response of parasite susceptible snails as compared to resistant snails and with normal or live, attenuated parasites. Interestingly, the stress response gene heat shock protein (Hsp) 70 is only repositioned and then up-regulated in susceptible snails with the normal parasite. This movement and change in gene expression seems to be controlled by the parasite. Other differences in the behaviour of genes support the view that some genes are responding to tissue damage, for example the ferritin genes move and are up-regulated whether the snails are either susceptible or resistant and upon exposure to either normal or attenuated parasite. This is the first time host genome reorganisation has been seen in a parasitic host and only the second time for any pathogen. We believe that the parasite elicits a spatio-epigenetic reorganisation of the host genome to induce favourable gene expression for itself and this might represent a fundamental mechanism present in the human host infected with schistosome cercariae as well as in other host-pathogen relationships. PMID:25211244

  7. The utility of surface temperature measurements for the remote sensing of surface soil water status

    NASA Technical Reports Server (NTRS)

    Idso, S. B.; Jackson, R. D.; Reginato, R. J.; Schmugge, T. J.

    1975-01-01

    Experiments carried out on an Avondale loam soil indicated that the thermal inertia concept of soil water content detection is reasonably sound. The volumetric water contents of surface soil layers between 2 and 4 cm thick were found to be linear functions of the amplitude of the diurnal surface soil temperature wave for clear day-night periods. They were also found to be linear functions of the daily maximum value of the surface soil-air-temperature differential. Tests on three additional soils ranging from sandy loam to clay indicated that the relations determined for Avondale loam could not be accurately applied to these other soil types. When the moisture characteristic curves of each soil were used to transform water contents into pressure potentials, however, it was found that soil water pressure potential could be determined without prior knowledge of soil type, and thus its value as a potential soil water status survey tool was significantly enhanced.

  8. Spatial development of the wind-driven water surface flow

    NASA Astrophysics Data System (ADS)

    Chemin, Rémi; Caulliez, Guillemette

    2015-04-01

    The water velocity field induced by wind and waves beneath an air-water interface is investigated experimentally versus fetch in the large Marseille-Luminy wind wave tank. Measurements of the vertical velocity profiles inside the subsurface shear layer were performed by a three-component Nortek acoustic Doppler velocimeter. The surface drift current was also derived from visualizations of small floating drifters recorded by a video camera looking vertically from above the water surface. Surface wave height and slopes were determined simultaneously by means of capacitance gauges and a single-point laser slope system located in the immediate vicinity of the profiler. Observations were made at steady low to moderate wind speeds and various fetches ranging between 1 and 15 meters. This study first corroborates that the thin subsurface water boundary layer forced by wind at the leading edge of the water sheet is laminar. The surface drift current velocity indeed increases gradually with fetch, following a 1/3 power law characteristic of an accelerated flat-plate laminar boundary layer. The laminar-turbulent transition manifests itself by a sudden decrease in the water surface flow velocity and a rapid deepening of the boundary layer due to the development of large-scale longitudinal vortices. Further downstream, when characteristic capillary-gravity wind waves develop at the surface, the water flow velocity increases again rapidly within a sublayer of typically 4 mm depth. This phenomenon is explained by the occurrence of an intense momentum flux from waves to the mean flow due to the dissipation of parasitic capillaries generated ahead of the dominant wave crests. This phenomenon also sustains significant small-scale turbulent motions within the whole boundary layer. However, when gravity-capillary waves of length longer than 10 cm then grow at the water surface, the mean flow velocity field decreases drastically over the whole boundary layer thickness. At the same time, long-lived three-dimensional coherent structures which present strong similarities with the so-called Langmuir circulations start to grow. The main features of the wind-induced water surface flow observed at these different stages of development will be compared with previous observations and the results of numerical simulations as described by Tsai et al. (2005, 2009).

  9. Water resources data for Florida, water year 1992. Volume 2A. South Florida surface water. Water-data report (Annual), 1 October 1991-30 September 1992

    Microsoft Academic Search

    W. J. Haire; C. Price

    1993-01-01

    The data for South Florida included continuous or daily discharge for 75 streams, continuous or daily stage for 61 streams, continuous elevation for 1 lake; continuous ground-water levels for 220 wells, periodic ground-water levels for 320 wells and miscellaneous water-level measurements for 329 wells; quality-of-water for 3 surface-water sites and 545 wells.

  10. Epigenetic Regulation of EMT: The Snail Story

    PubMed Central

    Lin, Yiwei; Dong, Chenfang; Zhou, Binhua P.

    2014-01-01

    While the epithelial-mesenchymal transition (EMT) plays a fundamental role during development, its deregulation can adversely promote tumor metastasis. The phenotypic and cellular plasticity of EMT indicates that it is subject to epigenetic regulation. In this review, we try to embrace recent findings on the mechanisms of the transcription factor Snail-mediated E-cadherin silencing, which is a hallmark of EMT. Our studies as well as those of others have clearly demonstrated that Snail can recruit multiple chromatin enzymes including LSD1, HDAC1/2, PRC2, G9a and Suv39H1 to the E-cadherin promoter. These enzymes function in a highly orchestrated fashion to generate heterochromatin and promote DNA methyltransferase (DNMT)-mediated DNA methylation at the promoter region. Disruption of the connection between Snail and these chromatin-modifying enzymes may represent an efficient strategy for the treatment of EMT-related diseases. PMID:23888971

  11. Computer programs for modeling flow and water quality of surface water systems

    USGS Publications Warehouse

    Lorens, J.A.

    1982-01-01

    A selection of available computer programs for modeling flow and water quality in surface water systems is described. The models include programs developed as part of the U.S. Geological Survey Water Resources Division hydrologic research activities and others developed by other agencies, universities, and consulting firms. Each model description includes a statement of program use; data requirements; computer costs; availability of documentation and reference material; and a contact person for additional information. The report is intended to assist the researcher by presenting a very brief description of the surface-water models which are readily available for project use. (USGS)

  12. Sputtering effects and water formation on an amorphous silicate surface.

    PubMed

    Jing, Dapeng; He, Jiao; Bonini, Massimo; Brucato, John R; Vidali, Gianfranco

    2013-04-11

    We studied the formation of deuterated water on an amorphous silicate surface held at low temperature (10 K < T < 40 K). The surface is first characterized by using Ar(+) ion bombardment, and preferential sputtering of oxygen is found. Sputtering creates oxygen vacancies in the surface region that can be filled by deposition of atomic oxygen. The conditions used in the experiment are meant to make it relevant to the study of the initial stages of water formation on dust grains in interstellar space. By changing the D/O ratio of atomic beams of deuterium and oxygen at thermal energy and the temperature of the sample during deposition, we show that the routes to the formation of D2O2 can be untangled and, under certain circumstances, the net yield of D2O2 can be suppressed. The formation efficiency for water and other molecules is then estimated. PMID:23505999

  13. Surface-water and climatological data, Salt Lake County, Utah, water year 1980

    USGS Publications Warehouse

    Pyper, G.E.; Christensen, R.C.; Stephens, D.W.; McCormack, H.F.; Conroy, L.S.

    1981-01-01

    This report presents streamflow, water-quality, precipitation, and storm-runoff data collected in Salt Lake County, Utah, during the 1980 water year and certain water-quality data for the 1979 water year which were included for comparative purposes. Surface-water data consist of daily mean values of flow at 33 sites on natural streams, canals, and conduits. Water-quality data consist of chemical, biologic, and sediment analyses at 30 sites. Precipitation data consist of daily and monthly total at nine sites. Storm-runoff data consist of 5 and 15-minute interval discharge data for storms of July 1-2, August 19, and August 25, 1980, for most surface-water sites. (USGS)

  14. The effect of surface water and wetting on gecko adhesion.

    PubMed

    Stark, Alyssa Y; Sullivan, Timothy W; Niewiarowski, Peter H

    2012-09-01

    Despite profound interest in the mechanics and performance of the gecko adhesive system, relatively few studies have focused on performance under conditions that are ecologically relevant to the natural habitats of geckos. Because geckos are likely to encounter surfaces that are wet, we used shear force adhesion measurements to examine the effect of surface water and toe pad wetting on the whole-animal performance of a tropical-dwelling gecko (Gekko gecko). To test the effect of surface wetting, we measured the shear adhesive force of geckos on three substrate conditions: dry glass, glass misted with water droplets and glass fully submerged in water. We also investigated the effect of wetting on the adhesive toe pad by soaking the toe pads prior to testing. Finally, we tested for repeatability of the adhesive system in each wetting condition by measuring shear adhesion after each step a gecko made under treatment conditions. Wetted toe pads had significantly lower shear adhesive force in all treatments (0.86 ± 0.09 N) than the control (17.96 ± 3.42 N), as did full immersion in water (0.44 ± 0.03 N). Treatments with droplets of water distributed across the surface were more variable and did not differ from treatments where the surface was dry (4.72 ± 1.59 N misted glass; 9.76 ± 2.81 N dry glass), except after the gecko took multiple steps. These findings suggest that surface water and the wetting of a gecko's adhesive toe pads may have significant consequences for the ecology and behavior of geckos living in tropical environments. PMID:22875772

  15. Zirconium fluoride glass - Surface crystals formed by reaction with water

    NASA Technical Reports Server (NTRS)

    Doremus, R. H.; Bansal, N. P.; Bradner, T.; Murphy, D.

    1984-01-01

    The hydrated surfaces of a zirconium barium fluoride glass, which has potential for application in optical fibers and other optical elements, were observed by scanning electron microscopy. Crystalline zirconium fluoride was identified by analysis of X-ray diffraction patterns of the surface crystals and found to be the main constituent of the surface material. It was also found that hydrated zirconium fluorides form only in highly acidic fluoride solutions. It is possible that the zirconium fluoride crystals form directly on the glass surface as a result of its depletion of other ions. The solubility of zirconium fluoride is suggested to be probably much lower than that of barium fluoride (0.16 g/100 cu cm at 18 C). Dissolution was determined to be the predominant process in the initial stages of the reaction of the glass with water. Penetration of water into the glass has little effect.

  16. The use of radar imagery for surface water investigations

    NASA Technical Reports Server (NTRS)

    Bryan, M. L.

    1981-01-01

    The paper is concerned with the interpretation of hydrologic features using L-band (HH) imagery collected by aircraft and Seasat systems. Areas of research needed to more precisely define the accuracy and repeatability of measurements related to the conditions of surfaces and boundaries of fresh water bodies are identified. These include: the definition of shoreline, the nature of variations in surface roughness across a water body and along streams and lake shores, and the separation of ambiguous conditions which appear similar to lakes.

  17. Regularity of traveling free surface water waves with vorticity

    E-print Network

    Li, Wei-Xi

    2011-01-01

    We prove real analyticity of all the streamlines, including the free surface, of a gravity- or capillary-gravity-driven steady flow of water over a flat bed, with a H\\"{o}lder continuous vorticity function, provided that the propagating speed of the wave on the free surface exceeds the horizontal fluid velocity throughout the flow. Furthermore, if the vorticity possesses some Gevrey regularity of index $s$, then the stream function admits the same Gevrey regularity throughout the fluid domain; in particular if the Gevrey index $s$ equals to 1, then we obtain analyticity of the stream function. The regularity results hold for both periodic and solitary water waves.

  18. Parametrically excited water surface ripples as ensembles of oscillons

    E-print Network

    Shats, Michael; Punzmann, Horst

    2011-01-01

    We show that ripples on the surface of deep water which are driven parametrically by monochromatic vertical vibration represent ensembles of oscillating solitons, or quasi-particles, rather than waves. Horizontal mobility of oscillons determines the broadening of spectral lines and transitions from chaos to regular patterns. It is found that microscopic additions of proteins to water dramatically affect the oscillon mobility and drive transitions from chaos to order. The shape of the oscillons in physical space determines the shape of the frequency spectra of the surface ripple.

  19. Water surface reconstruction system for underwater target detection

    NASA Astrophysics Data System (ADS)

    Zhou, Jiangying; Storm, Henrik; Sinzinger, Eric D.; Myrick, Michael L.

    1999-08-01

    This paper presents the result of an ONR-sponsored ocean- surface reconstruction project. The goal of the LIDAR project is to investigate a method suitable for obtaining the shape, and in particular, the slopes of the large gravitational waves, to be used in a Navy application for under-water mine detection. Towards this goal, Summus has designed, built and tested a laser-based device for water surface measurement. A field test was conducted at the Army Field Research Facility at Kitty Hawk, North Carolina in October 1998. This paper describes the basic design conducted of our method, and the experimental results.

  20. Influence of Physical Factors on Trichloroethylene Evaporation from Surface Water

    Microsoft Academic Search

    Prabhakar Pant; Marshall Allen; Yong Cai; Krishnaswamy Jayachandran; Yin Chen

    2007-01-01

    Evaporation of trichloroethylene (TCE) is a viable option in the remediation of TCE contaminated water. In this study, laboratory\\u000a batch experiments were conducted to understand the evaporation kinetics of TCE in surface water, with further extension of\\u000a this knowledge to field application. Experiments were set up for 15, 30, 60, and 90 min time intervals in open glass containers\\u000a with initial

  1. Surface charge of electrosprayed water nanodroplets: a molecular dynamics study.

    PubMed

    Ahadi, Elias; Konermann, Lars

    2010-08-18

    Aqueous nanodroplets that contain excess charge carriers play a central role during the electrospray ionization (ESI) process. An interesting question concerns the charge carrier location in these systems. In analogy to the behavior of metallic conductors, it is often assumed that excess ions are confined to a thin layer on the droplet surface. However, it is unclear whether simple electrostatic arguments adequately reflect the nanodroplet behavior. In particular, most ions tend to be heavily solvated, such that placing them at the liquid/vapor interface would be enthalpically unfavorable. In this work, molecular dynamics simulations are used to study the properties of Na(+)-containing water nanodroplets close to the Rayleigh limit. In apparent violation of the surface charge paradigm, it is found that the ions reside inside the droplet. Electrostatic mapping reveals that all of the excess charge is nonetheless located on the surface. This conundrum is resolved by considering the effects of orientational water polarization. Buried Na(+) ions cause large-scale dipole ordering that extends all the way to the droplet periphery. Here, the positive ends of water dipoles preferentially point into the vapor phase. These half-dipoles in the outermost droplet layers assume the role of surface charge, while solvation effectively neutralizes Na(+) ions in the interior. Overall, our data reaffirm the validity of the surface charge paradigm for ESI nanodroplets, albeit with the caveat that this paradigm does NOT require charge carriers (ions) to be located at the water/vapor interface. PMID:20698694

  2. methodology to classify groundwater/surface water interaction

    NASA Astrophysics Data System (ADS)

    Nilsson, B.; Christensen, S.; Kronvang, B.; Langhoff, J. H.; Dahl, M.; Hoffmann, C. C.; Andersen, H. E.; Rasmussen, K. R.; Refsgaard, J. C.

    2003-04-01

    Introductory work on implementation of the EU Water Framework Directive has outlined criteria for classification of the physical-chemical status of groundwater and surface water bodies, recognizing that the quantitative and qualitative status of ground water may have an impact on the quantitative, qualitative and ecological status of surface waters if the two bodies interact. In Denmark the implementation of the Directive has started with classifying separately the status of ground water and the status of streams. This is done within each of many districts supposed to be responsible for the future’s water supply. Within each district the next step is to define to what extent ground water has (and is expected to have in the future) impact on the streams, and vice versa. This has motivated the present work on developing a methodology to classify how ground water interacts with surface waters in Danish stream valleys. The classification has got the acronym GOI-type, which is identical with the English term GSI-class (Groundwater/Surface water Interaction classification). To make the methodology operational the classification is made mainly on basis of already available information (from maps, data bases and previous investigations), and it is made in steps going from regional scale (hundreds of kilometers) over catchment scale (tens of kilometers) to the stream valley scale (hundreds of meters). On the regional scale it is classified whether the geological environment controlling water flow and solute transport is dominated by bedrock or sedimentary rock since the physical and chemical processes are very different in these two environments. On catchment scale the classification differentiates between various landscape types because the landscape creating processes have resulted in different geologic and geomorphologic environments from which for example a model of permeable and semi-permeable layers controlling groundwater recharge and flow can be produced. Available hydrological data are used to characterize whether or not there is aquifers near the stream valley through which ground water can flow to the valley. This together with information about stream valley topography, geomorphology, possible anthropogenic changes in the valley (for example drains or ditches), and expected values for process controlling parameters are used to estimate the quantity, quality and variation of groundwater flow into the valley and to characterize how the ground water interacts with the stream and its surrounding sediments (expected flow paths and physical/chemical reactions).

  3. DISTRIBUTION OF ORGANIC WASTEWATER CONTAMINANTS BETWEEN WATER AND SEDIMENT IN SURFACE WATERS OF THE UNITED STATES

    EPA Science Inventory

    Trace concentrations of pharmaceuticals and other organic wastewater contaminants have been determined in the surface waters of Europe and the United States. A preliminary report of substantially higher concentrations of pharmaceuticals in sediment suggests that bottom sediment ...

  4. Interim report on surface water resources and quality of waters in Lee County, Florida

    USGS Publications Warehouse

    Kenner, William E.; Brown, Eugene

    1956-01-01

    The purpose of this report is to provide such information on the surface-water resources of the county as inay be useful in planning for their more intensive use. This report is not intended to provide final answers to all questions concerning the occurrence of surface water in the c:ounty; because of the paucity of information on the various streams in the area. However, as an initial step it should prove valuable in the formulation of plans for the future.

  5. Water loss through evaporation from water surfaces of lakes and reservoirs in Turkey

    Microsoft Academic Search

    Ferhat Gökbulak; Süleyman Özhan

    2006-01-01

    The objective of this study2 was to estimate the amount of evaporative loss from fresh water lake and reservoir surfaces in Turkey and to compare it with supplied water in Turkey. In this study 129 lakes and 223 reservoirs were subjected to evaporation estimates. The total surface area was 3213.97 km2 and 4026.16 km2 for the lakes and the reservoirs,

  6. Temperature relations of aerial and aquatic respiration in six littoral snails in respiration in six littoral snails in relation to their vertical zonation.

    PubMed

    McMahon, R F; Russell-Hunter, W D

    1977-04-01

    Aerial and aquatic rates of oxygen consumption were determined over a range of 5 degrees to 45 degrees C at 5 degrees C intervals for six species of marine littoral snails: including the sublittoral species, Acmaea testudinalis, Mitrella lunata, and Lacuna vincta; and the truly intertidal species, Littorina obtusata, L. littorea, and L. saxatilis. Polarographic oxygen electrodes were used with normally active snails collected from populations on Nobska and Manomet Points, Massachusetts. Three subtidal species, A. testudinalis, Lacuna vincta, and M. lunata, do not display any metabolic adjustment to increasing temperature, with thermal limits reached at 30 degrees to 35 degrees C. Aerial respiration in A. testudinalis is similar to aquatic O2 uptake, but rates average only 36.4% of aquatic rates. The intertidal congeners, Littorina obtusata, L. littorea and L. saxatilis, have varying degrees of aerial and aquatic metabolic regulation with increasing temperature. L. obtusata, a low intertidal snail exposed to air for 15% to 45% of the tidal cycle, displays a respiratory pattern of "passive endurance" to high temperatures both in air and in water. L. littorea, the dominant snail of the midlittoral region, remains active when exposed to air (30% to 75% of the tidal cycle) and has a zone of metabolic regulation between 20 degrees C and 30 degrees C. Over this, the normal ambient temperature range, the Q10 closely approximates one, and nearly equivalent O2 uptake rates occur in air and in water. L. saxatilis from the upper littoral region is exposed to air for 70% to 95% of the tidal cycle and is characterized by reduced aerial and aquatic O2 uptake rates above 25 degrees C, representing a reversible torpor up to its thermal maximum at 44 degrees C. For these six snail species, respiratory responses to increasing temperature are thus directly related to the pattern of vertical distribution in the intertidal environment. Discussion of this relationship stresses that the evolution of other nearterrestrial structures and functions in littoral snails has proceeded in a discontinuous fashion. Despite this, the temperature responses in respiration parallel the functional morphology of the pallial structures and the physiological patterns of response to low oxygen stress, as well as adaptive features of reproduction, larval development, water-control, and nitrogenous excretion. PMID:856295

  7. Global atmospheric mass, surface pressure, and water vapor variations

    NASA Astrophysics Data System (ADS)

    Trenberth, Kevin E.; Christy, John R.; Olson, Jerry G.

    1988-01-01

    Variations in the hydrological cycle and the water vapor content of the atmosphere form a vital part of the "greenhouse" feedback mechanism that can substantially enhance perturbations in the atmosphere arising from changes in forcing, such as those associated with increases in the carbon dioxide content of the atmosphere. An analysis is therefore made of the mean annual cycle interannual variability and trends in global-scale water vapor content of the atmosphere for December 1978 through December 1985, using global analyses from the European Centre for Medium Range Weather Forecasts. Since the variations in total atmospheric mass are almost entirely due to water vapor, two entirely independent global measures of the water vapor content can be compared. These are the total surface pressure due to water vapor from humidity analyses and the total surface pressure itself. For the mean annual cycle these show excellent agreement, and the analyses are therefore compatible with the constraint that the total mass of dry air is conserved. However, it appears that both the interannual variability and trends in water vapor are sufficiently small that they are lost in the noise level of the data, A new estimate of the total mass of the atmosphere is 5.1361×1018 kg for the annual mean, corresponding to a mean surface pressure of 984.43 mbar. It ranges from 5.1352×1018 kg in January to 5.1371×1018 kg in July, owing to the annual cycle in global water vapor which has an amplitude of 1.0×1015 kg (0.2 mbar). The total mass of dry air is estimated to be 5.123×1018 kg (or 981.9 mbar). Also presented is the partitioning of the mass for both the total and the water vapor into the contributions from each hemisphere and as a function of latitude. Mean annual surface pressures in the northern and southern hemispheres are found to be 981.92 and 986.93 mbar, respectively. Monthly mean hemispheric fluctuations in surface pressures of ±1 mbar are not uncommon and tend to be reflected by opposite anomalies in the other hemisphere (consistent with conservation of mass), but the residual in the global monthly mean is of the order of 0.1 mbar. Since this is greater than the magnitude of the possible signal in water vapor surface pressure, the available evidence indicates that the analyzed global monthly anomalies are mostly noise.

  8. Global atmospheric mass, surface pressure, and water vapor variations

    NASA Astrophysics Data System (ADS)

    Trenberth, Kevin E.; Christy, Johan R.; Olson, Jerry G.

    1987-12-01

    Variations in the hydrological cycle and the water vapor content of the atmosphere form a vital part of the "greenhouse" feedback mechanism that can substantially enhance perturbations in the atmosphere arising from changes in forcing, such as those associated with increases in the carbon dioxide content of the atmosphere. An analysis is therefore made of the mean annual cycle, interannual variability and trends in global-scale water vapor content of the atmosphere for December 1978 through December 1985, using global analyses from the European Centre for Medium Range Weather Forecasts. Since the variations in total atmospheric mass are almost entirely due to water vapor, two entirely independent global measures of the water vapor content can be compared. These are the total surface pressure due to water vapor from humidity analyses and the total surface pressure itself. For the mean annual cycle these show excellent agreement, and the analyses are therefore compatible with the constraint that the total mass of dry air is conserved. However, it appears that both the interannual variability and trends in water vapor are sufficiently small that they are lost in the noise level of the data. A new estimate of the total mass of the atmosphere is 5.1361×1018 kg for the annual mean, corresponding to a mean surface pressure of 984.43 mbar. It ranges from 5.1352×1018 kg in January to 5.1371×1018 kg in July, owing to the annual cycle in global water vapor which has an amplitude of 1.0×1015 kg (0.2 mbar). The total mass of dry air is estimated to be 5.123×1018 kg (or 981.9 mbar). Also presented is the partitioning of the mass for both the total and the water vapor into the contributions from each hemisphere and as a function of latitude. Mean annual surface pressures in the northern and southern hemispheres are found to be 981.92 and 986.93 mbar, respectively. Monthly mean hemispheric fluctuations in surface pressures of ±1 mbar are not uncommon and tend to be reflected by opposite anomalies in the other hemisphere (consistent with conservation of mass), but the residual in the global monthly mean is of the order of 0.1 mbar. Since this is greater than the magnitude of the possible signal in water vapor surface pressure, the available evidence indicates that the analyzed global monthly anomalies are mostly noise.

  9. NAWQA RETROSPECTIVE DATABASE FOR NUTRIENTS IN GROUND WATER AND SURFACE WATER

    EPA Science Inventory

    The National Water-Quality Assessment (NAWQA) Program is designed to describe the status and trends in the quality of the Nations ground- and surface-water resources and to provide a sound understanding of the natural and human factors that affect the quality of these resources. ...

  10. Survey of the Mutagenicity of Surface Water, Sediments, and Drinking Water from the Penobscot Indian Nation.

    EPA Science Inventory

    Survey of the Mutagenicity of Surface Water, Sediments, andDrinking Water from the Penobscot Indian NationSarah H. Warren, Larry D. Claxton,1, Thomas J. Hughes,*, Adam Swank,Janet Diliberto, Valerie Marshall, Daniel H. Kusnierz, Robert Hillger, David M. DeMariniNational Health a...

  11. Manure Phosphorus and Surface Water Protection I: Basic Concepts of Soil and Water P

    NSDL National Science Digital Library

    This lesson focuses on the process of eutrophication; the relationship between land application of manure and soil phosphorus (P) dynamics on P delivery to surface waters; and on the P dynamics in water bodies that result in increased P available to aquatic vegetation.

  12. Surface water data at Los Alamos National Laboratory: 2009 water year

    SciTech Connect

    Ortiz, David; McCullough, Betsy

    2010-05-01

    The principal investigators collected and computed surface water discharge data from 73 stream-gage stations that cover most of Los Alamos National Laboratory and one at Bandelier National Monument. Also included are discharge data from three springs— two that flow into Cañon de Valle and one that flows into Water Canyon.

  13. Surface water data at Los Alamos National Laboratory: 2008 water year

    SciTech Connect

    Ortiz, David; Cata, Betsy; Kuyumjian, Gregory

    2009-09-01

    The principal investigators collected and computed surface water discharge data from 69 stream-gage stations that cover most of Los Alamos National Laboratory and one at Bandelier National Monument. Also included are discharge data from three springs— two that flow into Cañon de Valle and one that flows into Water Canyon.

  14. Surface Water Data at Los Alamos National Laboratory 2006 Water Year

    SciTech Connect

    R.P. Romero, D. Ortiz, G. Kuyumjian

    2007-08-01

    The principal investigators collected and computed surface water discharge data from 44 stream-gaging stations that cover most of Los Alamos National Laboratory and one at Bandelier National Monument. Also included are discharge data from three springs--two that flow into Canon de Valle and one that flows into Water Canyon--and peak flow data for 44 stations.

  15. Evaluation of ATP measurements to detect microbial ingress by wastewater and surface water in drinking water.

    PubMed

    Vang, Óluva K; Corfitzen, Charlotte B; Smith, Christian; Albrechtsen, Hans-Jørgen

    2014-11-01

    Fast and reliable methods are required for monitoring of microbial drinking water quality in order to protect public health. Adenosine triphosphate (ATP) was investigated as a potential real-time parameter for detecting microbial ingress in drinking water contaminated with wastewater or surface water. To investigate the ability of the ATP assay in detecting different contamination types, the contaminant was diluted with non-chlorinated drinking water. Wastewater, diluted at 10(4) in drinking water, was detected with the ATP assay, as well as 10(2) to 10(3) times diluted surface water. To improve the performance of the ATP assay in detecting microbial ingress in drinking water, different approaches were investigated, i.e. quantifying microbial ATP or applying reagents of different sensitivities to reduce measurement variations; however, none of these approaches contributed significantly in this respect. Compared to traditional microbiological methods, the ATP assay could detect wastewater and surface water in drinking water to a higher degree than total direct counts (TDCs), while both heterotrophic plate counts (HPC 22 °C and HPC 37 °C) and Colilert-18 (Escherichia coli and coliforms) were more sensitive than the ATP measurements, though with much longer response times. Continuous sampling combined with ATP measurements displays definite monitoring potential for microbial drinking water quality, since microbial ingress in drinking water can be detected in real-time with ATP measurements. The ability of the ATP assay to detect microbial ingress is influenced by both the ATP load from the contaminant itself and the ATP concentration in the specific drinking water. Consequently, a low ATP concentration of the specific drinking water facilitates a better detection of a potential contamination of the water supply with the ATP assay. PMID:25086698

  16. Lake surface water temperature retrieval using advanced very high resolution radiometer and

    E-print Network

    Wunderle, Stefan

    Lake surface water temperature retrieval using advanced very high resolution radiometer high resolution radiometer (AVHRR) and Moderate Resolution Imaging Spectroradiometer sea surface temperature algorithms to derive operational lake surface water temperature (LSWT). A validation study

  17. Movement of agricultural chemicals between surface water and ground water, lower Cedar River basin, Iowa

    USGS Publications Warehouse

    Squillace, Paul J.; Caldwell, J.P.; Schulmeyer, P.M.; Harvey, C.A.

    1996-01-01

    Movement of alachlor, atrazine, cyanazine, deethylatrazine, deisopropylatrazine, and metolachlor between surface water and ground water in documented data collected from May 1989 through July 1991 at a study site in the lower Cedar River basin, Iowa. The principal source of atrazine, deethylatrazine, deisopropylatrazine, and metolachlor in the Cedar River during two periods of base flow in 1989 and 1990 was ground water discharged from the alluvial aquifer adjacent to the river.

  18. The Identification of Markers Segregating with Resistance to Schistosoma mansoni Infection in the Snail Biomphalaria glabrata

    Microsoft Academic Search

    Matty Knight; Andre N. Miller; Carolyn N. Patterson; Christopher G. Rowe; George Michaels; Daniel Carr; Charles S. Richards; Fred A. Lewis

    1999-01-01

    Both snail and parasite genes determine the susceptibility of the snail Biomphalaria glabrata to infection with the trematode Schistosoma mansoni. To identify molecular markers associated with resistance to the parasite in the snail host, we performed genetic crosses between parasite-resistant and -susceptible isogenic snails. Because resistance to infection in adult snails is controlled by a single locus, DNA samples from

  19. PHOTOREACTIONS IN SURFACE WATERS AND THEIR ROLE IN BIOGEOCHEMICAL CYCLES

    EPA Science Inventory

    During the past decade significant interest has developed in the influence of photochemical reactions on biogeochemical cycles in surface waters of lakes and the sea. A major portion of recent research on these photoreactions has focused on the colored component of dissolved org...

  20. Shale gas development impacts on surface water quality in Pennsylvania

    PubMed Central

    Olmstead, Sheila M.; Muehlenbachs, Lucija A.; Shih, Jhih-Shyang; Chu, Ziyan; Krupnick, Alan J.

    2013-01-01

    Concern has been raised in the scientific literature about the environmental implications of extracting natural gas from deep shale formations, and published studies suggest that shale gas development may affect local groundwater quality. The potential for surface water quality degradation has been discussed in prior work, although no empirical analysis of this issue has been published. The potential for large-scale surface water quality degradation has affected regulatory approaches to shale gas development in some US states, despite the dearth of evidence. This paper conducts a large-scale examination of the extent to which shale gas development activities affect surface water quality. Focusing on the Marcellus Shale in Pennsylvania, we estimate the effect of shale gas wells and the release of treated shale gas waste by permitted treatment facilities on observed downstream concentrations of chloride (Cl?) and total suspended solids (TSS), controlling for other factors. Results suggest that (i) the treatment of shale gas waste by treatment plants in a watershed raises downstream Cl? concentrations but not TSS concentrations, and (ii) the presence of shale gas wells in a watershed raises downstream TSS concentrations but not Cl? concentrations. These results can inform future voluntary measures taken by shale gas operators and policy approaches taken by regulators to protect surface water quality as the scale of this economically important activity increases. PMID:23479604

  1. Copper and nickel in surface waters of Otago Harbour

    Microsoft Academic Search

    R. J. Dickson; K. A. Hunter

    1981-01-01

    The concentrations of Cu and Ni soluble at pH 2 were measured in surface waters of Otago Harbour using methodology that pays careful attention to measurement and control of sources of trace metal contamination. Both elements were preconcentrated by coprecipitation with cobalt pyrrolidine dithiocarbamate and analysed by atomic absorption spectrometry with an overall extraction yield of 97%. Samples were not

  2. Water condensation on a super-hydrophobic spike surface

    Microsoft Academic Search

    R. D. Narhe; D. A. Beysens

    2006-01-01

    Condensation-induced water drop growth was studied on a super-hydrophobic spike surface. The dynamics are described by three main stages depending on the size of the drop with respect to the different spike pattern length scales. The initial stage is characterized by nucleation of the drops at the bottom (cavities) of the spikes. During the intermediate stage, large drops are surrounded

  3. Assessment of the surface water quality in Northern Greece

    Microsoft Academic Search

    V. Simeonov; J. A. Stratis; C. Samara; G. Zachariadis; D. Voutsa; A. Anthemidis; M. Sofoniou; Th. Kouimtzis

    2003-01-01

    The application of different multivariate statistical approaches for the interpretation of a large and complex data matrix obtained during a monitoring program of surface waters in Northern Greece is presented in this study. The dataset consists of analytical results from a 3-yr survey conducted in the major river systems (Aliakmon, Axios, Gallikos, Loudias and Strymon) as well as streams, tributaries

  4. Numerical modeling of runback water on ice protected aircraft surfaces

    Microsoft Academic Search

    Kamel M. Al-Khalil; Theo G. Keith Jr.; Kenneth J. Dewitt

    1992-01-01

    A numerical simulation for 'running wet' aircraft anti-icing systems is developed. The model includes breakup of the water film, which exists in regions of direct impingement, into individual rivulets. The wetness factor distribution resulting from the film breakup and the rivulet configuration on the surface are predicted in the numerical solution procedure. The solid wall is modeled as a multilayer

  5. CONTROLLING STORM WATER RUNOFF WITH TRADABLE CREDITS FOR IMPERVIOUS SURFACES

    EPA Science Inventory

    Storm water flow off impervious surface in a watershed can lead to stream degradation, habitat alteration, low base flows and toxic leading. We show that a properly designed tradable runoff credit (TRC) system creates economic incentives for landowners to employ best management p...

  6. Carbon dioxide supersaturation in the surface waters of lakes

    Microsoft Academic Search

    J. J. Cole; N. F. Caraco; G. W. Kling; T. K. Kratz

    1994-01-01

    Data on the partial pressure of carbon dioxide (COâ) in the surface waters from a large number of lakes (1835) with a worldwide distribution show that only a small proportion of the 4665 samples analyzed (less than 10 percent) were within {+-}20 percent of equilibrium with the atmosphere and that most samples (87 percent) were supersaturated. The mean partial pressure

  7. Uranium in US surface, ground, and domestic waters. Volume 2

    SciTech Connect

    Drury, J.S.; Reynolds, S.; Owen, P.T.; Ross, R.H.; Ensminger, J.T.

    1981-04-01

    The report Uranium in US Surface, Ground, and Domestic Waters comprises four volumes. Volumes 2, 3, and 4 contain data characterizing the location, sampling date, type, use, and uranium conentrations of 89,994 individual samples presented in tabular form. The tabular data in volumes 2, 3, and 4 are summarized in volume 1 in narrative form and with maps and histograms.

  8. RTK GPS water level measurement on dynamic sea surface

    Microsoft Academic Search

    Siti Hawa Mohd Ngagipar; Othman Mohd Yusof

    2011-01-01

    In recent years, Global Positioning System (GPS) receivers have been placed on buoys to determine the height of sea surface. GPS buoy always have an advantages over traditional techniques in measuring water level, which is their ability to determine heights relative to an absolute reference frame. There are scenarios where it is not practical or difficult to install a conventional

  9. Chemometric evaluation of surface water quality at regional level

    Microsoft Academic Search

    V. Librando

    1991-01-01

    To reduce the volume of information needed for the evaluation of the quality of some surface waters designated for purification, data gathered in a previous study on three rivers (Simeto, Alcantara and Oreto) in Sicily have been subjected to statistical multivariate analysis. The data base comprised twentyfive variables from eight sampling points at monthly intervals for one year. Such a

  10. Absorption of ammonia from atmospheric plumes by natural water surfaces

    Microsoft Academic Search

    Kenneth L. Calder

    1972-01-01

    A simple model is presented that incorporates the major features of atmospheric transport and diffusion of a NH3 plume together with aqueous absorption as the plume traverses a water surface. The model is based on the well-known concept of the deposition velocity, although empirical data concerning the latter is quite meager. A specific application is considered to the gas release

  11. Irreversible membrane fouling during ultrafiltration of surface water

    Microsoft Academic Search

    Katsuki Kimura; Yasushi Hane; Yoshimasa Watanabe; Gary Amy; Naoki Ohkuma

    2004-01-01

    For more efficient use of membranes, the control of irreversible membrane fouling, which can be defined as fouling requiring chemical reagents to be mitigated, is of importance. In this study, irreversible fouling caused by constituents in surface water was investigated, based on a long-term pilot scale study. The membrane employed was a low-pressure hydrophobic ultrafiltration (UF) membrane made of polysulfone

  12. Modeling the relationship between land use and surface water quality

    Microsoft Academic Search

    Susanna T. Y. Tong; Wenli Chen

    2002-01-01

    It is widely known that watershed hydrology is dependent on many factors, including land use, climate, and soil conditions. But the relative impacts of different types of land use on the surface water are yet to be ascertained and quantified. This research attempted to use a comprehensive approach to examine the hydrologic effects of land use at both a regional

  13. RATES, CONSTANTS, AND KINETICS FORMULATIONS IN SURFACE WATER QUALITY MODELING

    EPA Science Inventory

    Recent studies are reviewed to provide a comprehensive volume on state-of-the-art formulations used in surface water quality modeling along with accepted values for rate constants and coefficients. Topics covered include system geometric representation (spatial and temporal), phy...

  14. Predicting the breaking onset of surface water waves

    Microsoft Academic Search

    Alexander Babanin; Dmitry Chalikov; Ian Young; Ivan Savelyev

    2007-01-01

    Why do ocean waves break? Understanding this important and obvious property of the ocean surface has been elusive for decades. This paper investigates causes which lead deep-water two-dimensional initially monochromatic waves to break. Individual wave steepness is found to be the single parameter which determines whether the wave will break immediately, never break or take a finite number of wave

  15. Prospects for operational remote sensing of surface water

    Microsoft Academic Search

    Burn Hockey; Tim Richards; Henry Osmaston

    1990-01-01

    The major surface storages of liquid water in the land phase of the hydrological cycle comprise channel storage in lakes and rivers including ephemeral streams, overbank storage on floodplains, and soil moisture. Many workers have investigated the capacity, contents and behaviour of these storages using remote sensing techniques. These, despite problems of sampling frequency and spatial resolution, can yield useful

  16. Numerical simulation of free water surface in pump intake

    NASA Astrophysics Data System (ADS)

    Zhao, L. J.; Nohmi, M.

    2012-11-01

    The purpose of this paper is to verify the volume of fluid (VOF) method for simulating the free water surface flow in pump intake. With the increasing computer power, VOF method has been becoming a more flexible and accurate choice to replace the conventional fixed water surface method, because it does not require assumptions on the nature of air-water interface. Two examples are presented in this paper. The first example is presented for simulating the growth of air-entrained vortices. LES (Large Eddy Simulation) model, instead of RANS (Reynolds averaged Navier-Stokes) turbulence model, is used to capture the peak of circular velocity around the vortex core. Numerical result shows good agreement with the benchmark experiment carried by the Turbomachinery Society of Japan. The second example predicts the flow rate distribution in the pump intake consisting of one opened and two closed channels. VOF result is compared with the conventional fixed water surface method assuming free-slip boundary condition on the fluid interface. The difference of flow pattern in the opened channel indicates that numerical flow field is affected remarkably by the setup of boundary condition at air-water interface.

  17. Excess densities and equimolar surfaces for spherical cavities in water

    NASA Astrophysics Data System (ADS)

    Floris, Franca Maria

    2007-02-01

    For hard spheres with a radius up to 10Å in TIP4P water under ambient conditions, the author studies how the excess number of molecules at the accessible surface depends on the radius of the cavity. Simulation results derived from excess volumes are discussed in terms of radial distribution functions (rdfs), which compare well with extended simple point charge and theoretical rdfs from the literature. The excess number of molecules at the accessible surface inserted in the expression which refers to an arbitrary dividing surface enables one to find the position of the equimolar surface. The surface tension corresponding to this dividing surface was obtained from values of the free energy of cavity formation. For radii in the range of the simulation data, its behavior with curvature is quite different from that usually shown in the literature. A model, which describes how the excess number of molecules at the accessible surface changes with the radius, is discussed in the large length limit by examining consistent rdfs described by a simple analytical form. The inclusion in the model of a logarithmic term has also been considered. Comparison with theoretical results from the literature shows a good agreement for a cavity with a radius of 20Å. For a radius of 100Å and beyond, the model predicts instead sharper density profiles. Such differences have a poor effect on the surface tension at the equimolar surface.

  18. Allying with armored snails: the complete genome of gammaproteobacterial endosymbiont

    PubMed Central

    Nakagawa, Satoshi; Shimamura, Shigeru; Takaki, Yoshihiro; Suzuki, Yohey; Murakami, Shun-ichi; Watanabe, Tamaki; Fujiyoshi, So; Mino, Sayaka; Sawabe, Tomoo; Maeda, Takahiro; Makita, Hiroko; Nemoto, Suguru; Nishimura, Shin-Ichiro; Watanabe, Hiromi; Watsuji, Tomo-o; Takai, Ken

    2014-01-01

    Deep-sea vents harbor dense populations of various animals that have their specific symbiotic bacteria. Scaly-foot gastropods, which are snails with mineralized scales covering the sides of its foot, have a gammaproteobacterial endosymbiont in their enlarged esophageal glands and diverse epibionts on the surface of their scales. In this study, we report the complete genome sequencing of gammaproteobacterial endosymbiont. The endosymbiont genome displays features consistent with ongoing genome reduction such as large proportions of pseudogenes and insertion elements. The genome encodes functions commonly found in deep-sea vent chemoautotrophs such as sulfur oxidation and carbon fixation. Stable carbon isotope (13C)-labeling experiments confirmed the endosymbiont chemoautotrophy. The genome also includes an intact hydrogenase gene cluster that potentially has been horizontally transferred from phylogenetically distant bacteria. Notable findings include the presence and transcription of genes for flagellar assembly, through which proteins are potentially exported from bacterium to the host. Symbionts of snail individuals exhibited extreme genetic homogeneity, showing only two synonymous changes in 19 different genes (13?810 positions in total) determined for 32 individual gastropods collected from a single colony at one time. The extremely low genetic individuality in endosymbionts probably reflects that the stringent symbiont selection by host prevents the random genetic drift in the small population of horizontally transmitted symbiont. This study is the first complete genome analysis of gastropod endosymbiont and offers an opportunity to study genome evolution in a recently evolved endosymbiont. PMID:23924784

  19. Allying with armored snails: the complete genome of gammaproteobacterial endosymbiont.

    PubMed

    Nakagawa, Satoshi; Shimamura, Shigeru; Takaki, Yoshihiro; Suzuki, Yohey; Murakami, Shun-ichi; Watanabe, Tamaki; Fujiyoshi, So; Mino, Sayaka; Sawabe, Tomoo; Maeda, Takahiro; Makita, Hiroko; Nemoto, Suguru; Nishimura, Shin-Ichiro; Watanabe, Hiromi; Watsuji, Tomo-o; Takai, Ken

    2014-01-01

    Deep-sea vents harbor dense populations of various animals that have their specific symbiotic bacteria. Scaly-foot gastropods, which are snails with mineralized scales covering the sides of its foot, have a gammaproteobacterial endosymbiont in their enlarged esophageal glands and diverse epibionts on the surface of their scales. In this study, we report the complete genome sequencing of gammaproteobacterial endosymbiont. The endosymbiont genome displays features consistent with ongoing genome reduction such as large proportions of pseudogenes and insertion elements. The genome encodes functions commonly found in deep-sea vent chemoautotrophs such as sulfur oxidation and carbon fixation. Stable carbon isotope ((13)C)-labeling experiments confirmed the endosymbiont chemoautotrophy. The genome also includes an intact hydrogenase gene cluster that potentially has been horizontally transferred from phylogenetically distant bacteria. Notable findings include the presence and transcription of genes for flagellar assembly, through which proteins are potentially exported from bacterium to the host. Symbionts of snail individuals exhibited extreme genetic homogeneity, showing only two synonymous changes in 19 different genes (13?810 positions in total) determined for 32 individual gastropods collected from a single colony at one time. The extremely low genetic individuality in endosymbionts probably reflects that the stringent symbiont selection by host prevents the random genetic drift in the small population of horizontally transmitted symbiont. This study is the first complete genome analysis of gastropod endosymbiont and offers an opportunity to study genome evolution in a recently evolved endosymbiont. PMID:23924784

  20. Triangulation methods for height profile measurements on instationary water surfaces

    NASA Astrophysics Data System (ADS)

    Mulsow, Christian; Maas, Hans-Gerd; Westfeld, Patrick; Schulze, Matthias

    2008-04-01

    The precise measurement of water surface models or profiles plays an important role in experimental hydromechanics. Conventional gauge-based techniques often come with a large instrumental effort and a limited spatial resolution. The paper shows an efficient non-contact photogrammetric technique for the measurement of water-surface profiles, which is based on an extension of the well-known laser light sheet projection technique. While the original laser lightsheet triangulation technique is limited to surfaces with diffuse reflection properties, the developed technique is capable of measuring on reflecting instationary surfaces. This article presents the basic principle, potential and limitations of the method. Several evolution steps of the system with different applicability and different complexity are shown. A double projection plane system capable of simultaneously measuring water surface height and tilt profiles marks the ceiling of the development. Besides the geometrical models of different levels of complexity, system calibration procedures are described. The applicability of the techniques and their accuracy potential are shown in several practical tests.

  1. What happens when snails get sick?

    NSDL National Science Digital Library

    American Association for the Advancement of Science (AAAS; )

    2004-07-09

    Scientists used to think that the two major groups of animals, vertebrates and invertebrates, protected themselves from getting sick in very different ways. A new study in snails suggests that both groups' immune systems might be slightly more similar than previously thought.

  2. Population Control in Snails by Natural Inhibitors

    Microsoft Academic Search

    M. G. Levy; M. Tunis; H. Isseroff

    1973-01-01

    IN many areas of the world diseases such as schistosomiasis caused by trematodes, still cause misery to millions of people and much damage to livestock. Because a specific mollusc, often a snail, is necessary for the completion of the trematode life cycle, the elimination of that host would eradicate the disease. According to Southgate1 none of the molluscicides currently available

  3. Biological invasions: the case of planorbid snails

    Microsoft Academic Search

    J. P. Pointier; P. David; P. Jarne

    2005-01-01

    A large number of planorbid snails are now commonly transported by man mainly through the aquatic plant trade. However, only a restricted number of species establish viable populations in a new habitat and a more restricted number spread. Only five planorbid species can be ranked in this last category and can be considered as pests because of their role in

  4. Rate law analysis of water oxidation on a hematite surface.

    PubMed

    Le Formal, Florian; Pastor, Ernest; Tilley, S David; Mesa, Camilo A; Pendlebury, Stephanie R; Grätzel, Michael; Durrant, James R

    2015-05-27

    Water oxidation is a key chemical reaction, central to both biological photosynthesis and artificial solar fuel synthesis strategies. Despite recent progress on the structure of the natural catalytic site, and on inorganic catalyst function, determining the mechanistic details of this multiredox reaction remains a significant challenge. We report herein a rate law analysis of the order of water oxidation as a function of surface hole density on a hematite photoanode employing photoinduced absorption spectroscopy. Our study reveals a transition from a slow, first order reaction at low accumulated hole density to a faster, third order mechanism once the surface hole density is sufficient to enable the oxidation of nearest neighbor metal atoms. This study thus provides direct evidence for the multihole catalysis of water oxidation by hematite, and demonstrates the hole accumulation level required to achieve this, leading to key insights both for reaction mechanism and strategies to enhance function. PMID:25936408

  5. Rate Law Analysis of Water Oxidation on a Hematite Surface

    PubMed Central

    2015-01-01

    Water oxidation is a key chemical reaction, central to both biological photosynthesis and artificial solar fuel synthesis strategies. Despite recent progress on the structure of the natural catalytic site, and on inorganic catalyst function, determining the mechanistic details of this multiredox reaction remains a significant challenge. We report herein a rate law analysis of the order of water oxidation as a function of surface hole density on a hematite photoanode employing photoinduced absorption spectroscopy. Our study reveals a transition from a slow, first order reaction at low accumulated hole density to a faster, third order mechanism once the surface hole density is sufficient to enable the oxidation of nearest neighbor metal atoms. This study thus provides direct evidence for the multihole catalysis of water oxidation by hematite, and demonstrates the hole accumulation level required to achieve this, leading to key insights both for reaction mechanism and strategies to enhance function. PMID:25936408

  6. Water-mediated proton hopping on an iron oxide surface.

    PubMed

    Merte, Lindsay R; Peng, Guowen; Bechstein, Ralf; Rieboldt, Felix; Farberow, Carrie A; Grabow, Lars C; Kudernatsch, Wilhelmine; Wendt, Stefan; Lægsgaard, Erik; Mavrikakis, Manos; Besenbacher, Flemming

    2012-05-18

    The diffusion of hydrogen atoms across solid oxide surfaces is often assumed to be accelerated by the presence of water molecules. Here we present a high-resolution, high-speed scanning tunneling microscopy (STM) study of the diffusion of H atoms on an FeO thin film. STM movies directly reveal a water-mediated hydrogen diffusion mechanism on the oxide surface at temperatures between 100 and 300 kelvin. Density functional theory calculations and isotope-exchange experiments confirm the STM observations, and a proton-transfer mechanism that proceeds via an H(3)O(+)-like transition state is revealed. This mechanism differs from that observed previously for rutile TiO(2)(110), where water dissociation is a key step in proton diffusion. PMID:22605771

  7. Flow boiling of water on nanocoated surfaces in a microchannel

    E-print Network

    Phan, Hai Trieu; Marty, Philippe; Colasson, Stéphane; Gavillet, Jérôme

    2010-01-01

    Experiments were performed to study the effects of surface wettability on flow boiling of water at atmospheric pressure. The test channel is a single rectangular channel 0.5 mm high, 5 mm wide and 180 mm long. The mass flux was set at 100 kg/m2 s and the base heat flux varied from 30 to 80 kW/m2. Water enters the test channel under subcooled conditions. The samples are silicone oxide (SiOx), titanium (Ti), diamond-like carbon (DLC) and carbon-doped silicon oxide (SiOC) surfaces with static contact angles of 26{\\deg}, 49{\\deg}, 63{\\deg} and 103{\\deg}, respectively. The results show significant impacts of surface wettability on heat transfer coefficient.

  8. 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 demonstrates the importance of using multiple methods to improve estimates for time of travel of 1 year or less. ?? 2004 Elsevier B.V. All rights reserved.

  9. Assessing metaldehyde concentrations in surface water catchments and implications for drinking water abstraction

    NASA Astrophysics Data System (ADS)

    Asfaw, Alemayehu; Shucksmith, James; Smith, Andrea; Cherry, Katherine

    2015-04-01

    Metaldehyde is an active ingredient in agricultural pesticides such as slug pellets, which are heavily applied to UK farmland during the autumn application season. There is current concern that existing drinking water treatment processes may be inadequate in reducing potentially high levels of metaldehyde in surface waters to below the UK drinking water quality regulation limit of 0.1 µg/l. In addition, current water quality monitoring methods can miss short term fluctuations in metaldehyde concentration caused by rainfall driven runoff, hampering prediction of the potential risk of exposure. Datasets describing levels, fate and transport of metaldehyde in river catchments are currently very scarce. This work presents results from an ongoing study to quantify the presence of metaldehyde in surface waters within a UK catchment used for drinking water abstraction. High resolution water quality data from auto-samplers installed in rivers are coupled with radar rainfall, catchment characteristics and land use data to i) understand which hydro-meteorological characteristics of the catchment trigger the peak migration of metaldehyde to surface waters; ii) assess the relationship between measured metaldehyde levels and catchment characteristics such as land use, topographic index, proximity to water bodies and runoff generation area; iii) describe the current risks to drinking water supply and discuss mitigation options based on modelling and real-time control of water abstraction. Identifying the correlation between catchment attributes and metaldehyde generation will help in the development of effective catchment management strategies, which can help to significantly reduce the amount of metaldehyde finding its way into river water. Furthermore, the effectiveness of current water quality monitoring strategy in accurately quantifying the generation of metaldehyde from the catchment and its ability to benefit the development of effective catchment management practices has also been investigated.

  10. Cholesterol enhances surface water diffusion of phospholipid bilayers.

    PubMed

    Cheng, Chi-Yuan; Olijve, Luuk L C; Kausik, Ravinath; Han, Songi

    2014-12-14

    Elucidating the physical effect of cholesterol (Chol) on biological membranes is necessary towards rationalizing their structural and functional role in cell membranes. One of the debated questions is the role of hydration water in Chol-embedding lipid membranes, for which only little direct experimental data are available. Here, we study the hydration dynamics in a series of Chol-rich and depleted bilayer systems using an approach termed (1)H Overhauser dynamic nuclear polarization (ODNP) NMR relaxometry that enables the sensitive and selective determination of water diffusion within 5-10 Å of a nitroxide-based spin label, positioned off the surface of the polar headgroups or within the nonpolar core of lipid membranes. The Chol-rich membrane systems were prepared from mixtures of Chol, dipalmitoyl phosphatidylcholine and/or dioctadecyl phosphatidylcholine lipid that are known to form liquid-ordered, raft-like, domains. Our data reveal that the translational diffusion of local water on the surface and within the hydrocarbon volume of the bilayer is significantly altered, but in opposite directions: accelerated on the membrane surface and dramatically slowed in the bilayer interior with increasing Chol content. Electron paramagnetic resonance (EPR) lineshape analysis shows looser packing of lipid headgroups and concurrently tighter packing in the bilayer core with increasing Chol content, with the effects peaking at lipid compositions reported to form lipid rafts. The complementary capability of ODNP and EPR to site-specifically probe the hydration dynamics and lipid ordering in lipid membrane systems extends the current understanding of how Chol may regulate biological processes. One possible role of Chol is the facilitation of interactions between biological constituents and the lipid membrane through the weakening or disruption of strong hydrogen-bond networks of the surface hydration layers that otherwise exert stronger repulsive forces, as reflected in faster surface water diffusivity. Another is the concurrent tightening of lipid packing that reduces passive, possibly unwanted, diffusion of ions and water across the bilayer. PMID:25494784

  11. Water resources data for New Jersey, water year 1992. Volume 1. Surface-water data. Water-data report (Annual), 1 October 1991-30 September 1992

    SciTech Connect

    Bauersfeld, W.R.; Moshinsky, E.W.; Gurney, C.E.

    1993-05-01

    Water resources data for the 1992 water year for New Jersey consists of records of stage, discharge, and water quality of streams; stage, contents, and water quality of lakes and reservoirs; and water levels and water quality of ground water. The volume of the report contains discharge records for 99 gaging stations; tide summaries for 2 stations; stage and contents for 37 lakes and reservoirs; water quality for 95 surface-water sites. Also included are data for 65 crest-stage partial-record stations, 13 tidal crest-stage gages, and 94 low-flow partial-record stations.

  12. How water meets a hydrophobic surface: Reluctantly and with flucuations

    NASA Astrophysics Data System (ADS)

    Poynor Torigoe, Adele Nichole

    By definition hydrophobic substances hate water. Water placed on a hydrophobic surface will form a drop in order to minimize its contact area. What happens when water is forced into contact with a hydrophobic surface? One theory is that an ultra-thin low density region forms near the surface. This depleted region would have implications in such diverse areas as colloidal self-assembly, and the boundary conditions of fluid flow. However, the literature still remains divided as to whether or not such a depleted region exists. To investigate the existence of this layer, we have employed three surface-sensitive techniques, time-resolved phase-modulated ellipsometry, surface plasmon resonance, and X-ray reflectivity. Both ellipsometry and X-ray reflectivity provide strong evidence for the low-density layer and illuminate unexpected temporal behavior. Using all three techniques, we found surprising fluctuations at the interface with a non-Gaussian distribution and a single characteristic time on the order of tenths of seconds. This information supports the idea that the boundary fluctuates with something akin to capillary waves. We have also investigated the dependence of the static and dynamic properties of the hydrophobic/water interface on variables such as temperature, contact angle, pH, dissolved gasses, and sample quality, among others, in a hope to discover the root of the controversy in the literature. We found that the depletion layer is highly dependent on temperature, contact angle and sample quality. This dependence might explain some of the discrepancies in the literature as different groups often use hydrophobic surfaces with different properties.

  13. Sea, ice and surface water circulation, Alaskan Continental Shelf

    NASA Technical Reports Server (NTRS)

    Wright, F. F. (principal investigator); Sharma, G. D.

    1972-01-01

    The author has identified the following significant results. Two cruises were conducted in Cook Inlet to obtain ground truth. Forty-seven stations during 22-23 August and 68 stations during 25-29 September 1972 were occupied and temperature, salinity, percent light transmission, and suspended load of surface waters obtained. Similar data at various depths was also obtained at selected stations. Cook Inlet is an estuary with complex mixing of river discharges and ocean water. The Upper Cook Inlet shows a gradual and systematic decrease in salinity, however, west of Kenai the mixing of waters is complex. The sediments in suspension originating at the head of the inlet generally settle out east of Kenai and Drift River. Sediment load in suspension decreased gradually from 1700 mg/1 near Anchorage to about 50 mg/1 in the Narrows. In the Lower Cook Inlet the suspended load varied between 1-10 mg/1. Surface waters with sediments in suspension and ocean water with relatively lower sediment concentration are clearly discernible in ERTS-1 images obtained during September 18, 1972 pass over Cook Inlet. The movement and mixing of these waters can also be delineated in the images.

  14. Effects of 17?-methyltestosterone on the reproduction of the freshwater snail Biomphalaria glabrata.

    PubMed

    Rivero-Wendt, C L G; Borges, A C; Oliveira-Filho, E C; Miranda-Vilela, A L; Ferreira, M F N; Grisolia, C K

    2014-01-01

    17-?-methyltestosterone (MT) is a synthetic hormone used in fish hatcheries to induce male monosex. Snails hold promise as possible test models to assess chemicals acting on the endocrine system. Biomphalaria glabrata is an aquatic gastropod mollusk (Pulmonata, Planorbidae) that can be easily maintained in aquaria, predisposing the species for use in ecotoxicological testing. This study evaluated the reproductive effects of MT on B. glabrata by examining histological changes and its reproductive performance. Ten snails per group were exposed for 4 weeks to different concentrations of MT (0.01, 0.1, and 1.0 mg/L). The total number of laid eggs, egg mass per group, size of type V oocytes, and production of spermatozoids were determined. Reproduction of B. glabrata was affected by MT. At the lowest concentration (0.01 mg/L), MT caused a statistically significant increase in the number of egg mass per snail compared with controls unexposed to MT. Histopathology analyses showed an increase in the sperm production at the higher MT concentrations of 0.1 and 1.0 mg/L. Chromatographic analyses of water samples showed that MT concentrations rapidly declined within a 96-h period. These results highlight the importance of giving more support to regulatory authorities, since MT is not registered for use on fish hatcheries in many countries around the world. Wastewater from fish farms discharged into aquatic ecosystems should be monitored for MT residues, since its presence could compromise the reproduction of other native snail species. PMID:24615026

  15. Observation of dynamic water microadsorption on Au surface

    SciTech Connect

    Huang, Xiaokang, E-mail: xiaokang.huang@tqs.com; Gupta, Gaurav; Gao, Weixiang; Tran, Van; Nguyen, Bang; McCormick, Eric; Cui, Yongjie; Yang, Yinbao; Hall, Craig; Isom, Harold [TriQuint Semiconductor, Inc., 500 W Renner Road, Richardson, Texas 75080 (United States)

    2014-05-15

    Experimental and theoretical research on water wettability, adsorption, and condensation on solid surfaces has been ongoing for many decades because of the availability of new materials, new detection and measurement techniques, novel applications, and different scales of dimensions. Au is a metal of special interest because it is chemically inert, has a high surface energy, is highly conductive, and has a relatively high melting point. It has wide applications in semiconductor integrated circuitry, microelectromechanical systems, microfluidics, biochips, jewelry, coinage, and even dental restoration. Therefore, its surface condition, wettability, wear resistance, lubrication, and friction attract a lot of attention from both scientists and engineers. In this paper, the authors experimentally investigated Au{sub 2}O{sub 3} growth, wettability, roughness, and adsorption utilizing atomic force microscopy, scanning electron microscopy, reflectance spectrometry, and contact angle measurement. Samples were made using a GaAs substrate. Utilizing a super-hydrophilic Au surface and the proper surface conditions of the surrounding GaAs, dynamic microadsorption of water on the Au surface was observed in a clean room environment. The Au surface area can be as small as 12??m{sup 2}. The adsorbed water was collected by the GaAs groove structure and then redistributed around the structure. A model was developed to qualitatively describe the dynamic microadsorption process. The effective adsorption rate was estimated by modeling and experimental data. Devices for moisture collection and a liquid channel can be made by properly arranging the wettabilities or contact angles of different materials. These novel devices will be very useful in microfluid applications or biochips.

  16. Experimental Study of Water Droplet Vaporization on Nanostructured Surfaces

    NASA Astrophysics Data System (ADS)

    Padilla, Jorge, Jr.

    This dissertation summarizes results of an experimental exploration of heat transfer during vaporization of a water droplet deposited on a nanostructured surface at a temperature approaching and exceeding the Leidenfrost point for the surface and at lower surface temperatures 10-40 degrees C above the saturated temperature of the water droplet at approximately 101 kPa. The results of these experiments were compared to those performed on bare smooth copper and aluminum surfaces in this and other studies. The nanostructured surfaces were composed of a vast array of zinc oxide (ZnO) nanocrystals grown by hydrothermal synthesis on a smooth copper substrate having an average surface roughness of approximately 0.06 micrometer. Various nanostructured surface array geometries were produced on the copper substrate by performing the hydrothermal synthesis for 4, 10 and 24 hours. The individual nanostructures were randomly-oriented and, depending on hydrothermal synthesis time, had a mean diameter of about 500-700 nm, a mean length of 1.7-3.3 micrometers,and porosities of approximately 0.04-0.58. Surface wetting was characterized by macroscopic measurements of contact angle based on the droplet profile and calculations based on measurements of liquid film spread area. Scanning electron microscope imaging was used to document the nanoscale features of the surface before and after the experiments. The nanostructured surfaces grown by hydrothermal synthesis for 4 and 24 hours exhibited contact angles of approximately 10, whereas the surfaces grown for 10 hours were superhydrophilic, exhibiting contact angles typically less than 3 degrees. In single droplet deposition experiments at 101 kPa, a high-speed video camera was used to document the droplet-surface interaction. Distilled and degassed water droplets ranging in size from 2.5-4.0 mm were deposited onto the surface from heights ranging from approximately 0.2-8.1 cm, such that Weber numbers spanned a range of approximately 0-99. Heat transfer coefficients were determined from thermal measurements in the test apparatus. All experiments were conducted inside an ISO Class 5 clean room enclosure. It was observed that when a liquid water droplet impinged upon the ZnO nanostructured at surface temperatures less than 140 degrees C, the nominally spherical droplet spread into a thin film over the surface. The film thickness depended on many parameters but in general it measured approximately 100-400 micrometers. As a result, it was found that the droplet evaporated by film evaporation without initiating nucleate boiling. At wall superheat levels of 10-20 degrees C, it was found in some cases that the heat transfer coefficients were nearly 4 times greater than for those of nucleate boiling at the same superheat level. For these conditions, no bubble nucleation was observed visually, and, nevertheless, extremely high heat transfer coefficients resulting from rapid evaporation of the thin liquid film formed by the spreading droplet were observed. At high wall superheat levels, the vaporization process exhibited Leidenfrost droplet vaporization. The extreme wetting of the nanostructured surfaces resulted in high Leidenfrost transition temperatures in the range of 310-376 degrees C, among the highest in the literature, exceeding those exhibited by bare metal surfaces by 100 degrees C or more. The Leidenfrost transition was detected from a recording of the acoustic signal generated from each experiment during the deposition and subsequent evaporation process. It was defined as the first point for which there is no disturbance to the acoustical signal in the form of a sizzling sound beyond the initial violent popping generated during the droplet deposition. The results document a trend of increasing Leidenfrost temperature with decreasing contact angle, which is consistent with earlier studies. The results of this study are compared with earlier work in this area and the implications for applications are discussed.

  17. Climate and pH Predict the Potential Range of the Invasive Apple Snail (Pomacea insularum) in the Southeastern United States

    PubMed Central

    Byers, James E.; McDowell, William G.; Dodd, Shelley R.; Haynie, Rebecca S.; Pintor, Lauren M.; Wilde, Susan B.

    2013-01-01

    Predicting the potential range of invasive species is essential for risk assessment, monitoring, and management, and it can also inform us about a species’ overall potential invasiveness. However, modeling the distribution of invasive species that have not reached their equilibrium distribution can be problematic for many predictive approaches. We apply the modeling approach of maximum entropy (MaxEnt) that is effective with incomplete, presence-only datasets to predict the distribution of the invasive island apple snail, Pomacea insularum. This freshwater snail is native to South America and has been spreading in the USA over the last decade from its initial introductions in Texas and Florida. It has now been documented throughout eight southeastern states. The snail’s extensive consumption of aquatic vegetation and ability to accumulate and transmit algal toxins through the food web heighten concerns about its spread. Our model shows that under current climate conditions the snail should remain mostly confined to the coastal plain of the southeastern USA where it is limited by minimum temperature in the coldest month and precipitation in the warmest quarter. Furthermore, low pH waters (pH <5.5) are detrimental to the snail’s survival and persistence. Of particular note are low-pH blackwater swamps, especially Okefenokee Swamp in southern Georgia (with a pH below 4 in many areas), which are predicted to preclude the snail’s establishment even though many of these areas are well matched climatically. Our results elucidate the factors that affect the regional distribution of P. insularum, while simultaneously presenting a spatial basis for the prediction of its future spread. Furthermore, the model for this species exemplifies that combining climatic and habitat variables is a powerful way to model distributions of invasive species. PMID:23451090

  18. Storm water contamination and its effect on the quality of urban surface waters.

    PubMed

    Bara?kiewicz, Danuta; Chudzi?ska, Maria; Szpakowska, Barbara; ?wierk, Dariusz; Go?dyn, Ryszard; Dondajewska, Renata

    2014-10-01

    We studied the effect of storm water drained by the sewerage system and discharged into a river and a small reservoir, on the example of five catchments located within the boundaries of the city of Pozna? (Poland). These catchments differed both in terms of their surface area and land use (single- and multi-family housing, industrial areas). The aim of the analyses was to explain to what extent pollutants found in storm water runoff from the studied catchments affected the quality of surface waters and whether it threatened the aquatic organisms. Only some of the 14 studied variables and 22 chemical elements were important for the water quality of the river, i.e., pH, TSS, rain intensity, temperature, conductivity, dissolved oxygen, organic matter content, Al, Cu, Pb, Zn, Fe, Cd, Ni, Se, and Tl. The most serious threat to biota in the receiver came from the copper contamination of storm water runoff. Of all samples below the sewerage outflow, 74% exceeded the mean acute value for Daphnia species. Some of them exceeded safe concentrations for other aquatic organisms. Only the outlet from the industrial area with the highest impervious surface had a substantial influence on the water quality of the river. A reservoir situated in the river course had an important influence on the elimination of storm water pollution, despite the very short residence time of its water. PMID:24981877

  19. Water resources data, Maryland, Delaware, and Washington, D.C., water year 2000, volume 1. surface-water data

    USGS Publications Warehouse

    James, Robert W., Jr.; Saffer, Richard W.; Tallman, Anthony J.

    2001-01-01

    Water resources data for the 2000 water year for Maryland and Delaware consist of records of stage, discharge, and water quality of streams; stage and contents of lakes and reservoirs. This volume (Volume 1. Surface-Water Data) contains records for water discharge at 121 gaging stations; stage and contents of 1 reservoir; and water quality at 21 gaging stations. Also included are stage and discharge for 3 creststage partial-record stations, discharge only for 27 low-flow partial-record stations, and stage only for 5 tidal crest-stage partial-record stations. Additional water data were collected at various sites not involved in the systematic data-collection program and are published as miscellaneous measurements. These data represent that part of the National Water Data System operated by the U.S. Geological Survey and cooperating State, local, and Federal agencies in Maryland and Delaware.

  20. Water resources data for Maryland, Delaware, and Washington, D.C, water year 2003, volume 1. surface-water data

    USGS Publications Warehouse

    James, Robert W., Jr.; Saffer, Richard W.; Pentz, Robert H.; Tallman, Anthony J.

    2003-01-01

    Water resources data for the 2003 water year for Maryland, Delaware, and Washington, D.C. consist of records of stage, discharge, and water quality of streams; stage and contents of lakes and reservoirs. This volume (Volume 1. Surface-Water Data) contains records for water discharge at 140 gaging stations; stage and contents of 1 reservoir; and water quality at 17 gaging stations. Also included are stage and discharge for 3 crest-stage partial-record stations and stage only for 10 tidal crest-stage partial-record stations. Additional water data were collected at various sites not involved in the systematic data-collection program and are published as miscellaneous measurements. These data represent that part of the National Water Data System operated by the U.S. Geological Survey and cooperating State, local, and Federal agencies in Maryland, Delaware, and Washington, D.C.

  1. Water resources data for Maryland, Delaware, and Washington, D.C, water year 2002, Volume 1. surface-water data

    USGS Publications Warehouse

    James, Robert W., Jr.; Saffer, Richard W.; Pentz, Robert H.; Tallman, Anthony J.

    2003-01-01

    Water resources data for the 2002 water year for Maryland, Delaware, and Washington, D.C. consist of records of stage, discharge, and water quality of streams; stage and contents of lakes and reservoirs. This volume (Volume 1. Surface-Water Data) contains records for water discharge at 137 gaging stations; stage and contents of 1 reservoir; and water quality at 28 gaging stations. Also included are stage and discharge for 3 crest-stage partial-record stations and stage only for 8 tidal crest-stage partialrecord stations. Additional water data were collected at various sites not involved in the systematic data-collection program and are published as miscellaneous measurements. These data represent that part of the National Water Data System operated by the U.S. Geological Survey and cooperating State, local, and Federal agencies in Maryland, Delaware, and Washington, D.C.

  2. Water resources data Maryland, Delaware, and Washington, D.C.,water year 2005, Volume 1. Surface-water data

    USGS Publications Warehouse

    Saffer, Richard W.; Pentz, Robert H.; Tallman, Anthony J.

    2006-01-01

    Water resources data for the 2005 water year for Maryland, Delaware, and Washington, D.C. consist of records of stage, discharge, and water quality of streams; stage and contents of lakes and reservoirs. This volume (Volume 1. Surface-Water Data) contains records for water discharge at 145 gaging stations; stage and contents of 1 reservoir; stage only for 2 tidal gaging station; and water quality at 19 gaging stations. Also included are stage only for 11 tidal crest-stage partial-record stations. Additional water data were collected at various sites not involved in the systematic data-collection program and are published as miscellaneous measurements. These data represent that part of the National Water Data System operated by the U.S. Geological Survey and cooperating State, local, and Federal agencies in Maryland, Delaware, and Washington, D.C.

  3. Evaluation of the Surface-Water Quantity, Surface-Water Quality, and Rainfall Data-Collection Programs in Hawaii, 1994

    USGS Publications Warehouse

    Fontaine, Richard A.

    1996-01-01

    This report documents the results of an evaluation of the surface-water quantity, surface-water quality, and rainfall data-collection programs in Hawaii. Fourteen specific issues and related goals were identified for the surface-water quantity program and a geographic information systems (GIS) data base was developed summarizing information for all surface-water stream gages that have been operated in Hawaii by the U.S. Geological Survey. Changes in status, which for some gages includes discontinuing operation, need to be considered at 42 sites where data are currently collected. The current surface-water quantity data base was determined to be adequate to address only two of the 14 specific issues and related goals. Alternatives were identified to address the areas where future issues and goals could not be adequately addressed. Options include new and expanded data collection, use of regional regression analyses, hydrologic and hydraulic modeling, and analysis and publication of existing data. A total of 47 streams were identified where additional stream-gaging stations are needed. Evaluation of the surface-water quality program was limited to a description of the U.S. Geological Survey's historical and existing programs and available analyses of data. Limitations of the program are described which primarily included lack of data regarding suspended sediment, land-use effects, quality of stream discharge to oceans, background water quality and nonpoint sources of contamination. Evaluation of the rainfall data program indicated that identified future goals could be discussed as either regional, systems related, current needs, forecasting, water quality, or trend analysis related. To address these goals, data from about 2,000 rain gages, 528 of which are active, are available. Data were found to only partially meet identified goals. Alternatives discussed to address the limitations include the need for more recording gages, primarily in areas of high rainfall. Another area of concern was the potential that many plantations will close and the effect these closings would have on continued operation of the important long-term gages they operate. Evaluation of data-collection programs in Hawaii needs to be an ongoing process. Equally important, data being collected need to be summarized and made available through data bases and published reports.

  4. Searching for liquid water in Europa by using surface observatories.

    PubMed

    Khurana, Krishan K; Kivelson, Margaret G; Russell, Christopher T

    2002-01-01

    Liquid water, as far as we know, is an indispensable ingredient of life. Therefore, locating reservoirs of liquid water in extraterrestrial bodies is a necessary prerequisite to searching for life. Recent geological and geophysical observations from the Galileo spacecraft, though not unambiguous, hint at the possibility of a subsurface ocean in the Jovian moon Europa. After summarizing present evidence for liquid water in Europa, we show that electromagnetic and seismic observations made from as few as two surface observatories comprising a magnetometer and a seismometer offer the best hope of unambiguous characterization of the three-dimensional structure of the ocean and the deeper interior of this icy moon. The observatories would also help us infer the composition of the icy crust and the ocean water. PMID:12449858

  5. Dynamics in surface water solute concentrations and consequences for water quality monitoring

    NASA Astrophysics Data System (ADS)

    Rozemeijer, J.; Van der Velde, Y.; Broers, H. P.; van Geer, F.

    2012-04-01

    For the evaluation of action programs to reduce surface water pollution, water authorities invest heavily in water quality monitoring. However, sampling frequencies are generally insufficient to capture the dynamical behavior of solute concentrations. This results in large uncertainties in the estimates of loads and average concentrations, which complicates water quality assessments. The main causes of dynamics in groundwater and surface water quality are variations in human land management, biochemical processes, and meteorological conditions. In this study, we focused on the short-term variations in water quality that are normally not captured with common monthly measurement intervals. Our multi-scale experimental research setup in The Netherlands revealed that weather induced variations are the major cause of short-term variations in water quality. During rainfall events, the relative contribution of different flow routes (groundwater, tile drain, overland flow) to the total surface water discharge changes. These different flow routes have different residence times in the subsurface and therefore different chemical compositions. For example, our continuous nitrate concentration measurements repetitively showed a lowering in stream water nitrate concentrations in response to rainfall events. This lowering was caused by a temporal dilution of nitrate-rich tile drain effluent with nitrate-poor rainwater. On the other hand, the continuously measured phosphorus concentrations peaked during rainfall events due to the resuspension of phosphorus-rich sediments. We will also present the following options to deal with the highly dynamic behavior of solute concentrations in surface water quality monitoring practice: (1) use modern equipment for continuous concentration measurements, (2) measure average concentrations using passive samplers, and (3) use the explanatory strength of generally available high-frequency data (e.g. precipitation and discharge records) to reconstruct concentration patterns between low-frequency concentration measurements.

  6. Reduction of water surface tension significantly impacts gecko adhesion underwater.

    PubMed

    Stark, Alyssa Y; McClung, Brandon; Niewiarowski, Peter H; Dhinojwala, Ali

    2014-12-01

    The gecko adhesive system is dependent on weak van der Waals interactions that are multiplied across thousands of fine hair-like structures (setae) on geckos' toe pads. Due to the requirements of van der Waals forces, we expect that any interruption between the setae and substrate, such as a water layer, will compromise adhesion. Our recent results suggest, however, that the air layer (plastron) surrounding the superhydrophobic toe pads aid in expelling water at the contact interface and create strong shear adhesion in water when in contact with hydrophobic surfaces. To test the function of the air plastron, we reduced the surface tension of water using two surfactants, a charged anionic surfactant and a neutral nonionic surfactant. We tested geckos on three substrates: hydrophilic glass and two hydrophobic surfaces, glass with a octadecyl trichlorosilane self-assembled monolayer (OTS-SAM) and polytetrafluoroethylene (PTFE). We found that the anionic surfactant inhibited the formation of the air plastron layer and significantly reduced shear adhesion to all three substrates. Interestingly, the air plastron was more stable in the nonionic surfactant treatments than the anionic surfactant treatments and we found that geckos adhered better in the nonionic surfactant than in the anionic surfactant on OTS-SAM and PTFE but not on glass. Our results have implications for the evolution of a superhydrophobic toe pad and highlight some of the challenges faced in designing synthetic adhesives that mimic geckos' toes. PMID:24944119

  7. Surface-water exposure to quinoxyfen: Assessment in landscape vineyards

    NASA Astrophysics Data System (ADS)

    Merli, Annalisa; Reeves, Graham; Meregalli, Giovanna; Piccinini, Armando; Negri, Ilaria; Carmignano, Pasquale; Balderacchi, Matteo; Capri, Ettore

    2010-03-01

    SummaryProtection of surface- and ground-water quality is critical for economic viability, as well as for human health and the environment. Furthermore, maintenance of the biodiversity of natural aquatic ecosystems is very important. The objective of this paper is to report methodology developed for the assessment of the surface-water exposure to pesticide using as example the fungicide quinoxyfen because persistent, lipophylic and hazard for the aquatic organisms. Exposure monitoring was carried out over two years (2005 and 2006) following historical and subsequent applications in Italian vineyards and to investigate the presence of residue in non-target areas close to the crop receiving repeated applications. After development of the monitoring procedures, surface-water contamination and biota exposure were determined during and after field treatments. Very low concentrations were found in sediments, often in contradiction with model and laboratory results, leading to the conclusion that even the historical use of quinoxyfen in vineyards within the catchment was not contaminating sediment in water bodies, which was regarded as the natural sink for such a pesticide due to its strong sorptive properties. For biota, quinoxyfen residues in benthic macroinvertebrates and fish in the vast majority of the samples were below the corresponding limit of detection (LOD). Thus long-term accumulation of quinoxyfen in sediments and organisms of the aquatic ecosystems would not be expected due main to the environmental conditions of the landscape that mitigate the overall exposure.

  8. Assembled monolayers of hydrophilic particles on water surfaces.

    PubMed

    Moon, Geon Dae; Lee, Tae Il; Kim, Bongsoo; Chae, GeeSung; Kim, Jinook; Kim, SungHee; Myoung, Jae-Min; Jeong, Unyong

    2011-11-22

    A facile and quick approach to prepare self-assembled monolayers of water-dispersible particles on the water surface is presented. Particle suspensions in alcohols were dropped on a water reservoir to form long-range ordered monolayers of various particles, including spherical solid particles, soft hydrogel particles, metal nanoparticles, quantum dots, nanowires, single-wall carbon nanotubes (SWCNTs), nanoplates, and nanosheets. A systematic study was conducted on the variables affecting the monolayer assembly: the solubility parameter of spreading solvents, particle concentration, zeta potential of the particles in the suspension, surface tension of the water phase, hardness of the particles, and addition of a salt in the suspension. This method requires no hydrophobic surface treatment of the particles, which is useful to exploit these monolayer films without changing the native properties of the particles. The study highlights a quick 2D colloidal assembly without cracks in the wafer scale as well as transparent conductive thin films made of SWCNTs and graphenes. PMID:21962177

  9. Linking land use with pesticides in Dutch surface waters.

    PubMed

    Van't, Zelfde M T; Tamis, W L M; Vijver, M G; De Snoo, G R

    2012-01-01

    Compared with other European countries The Netherlands has a relatively high level of pesticide consumption, particularly in agriculture. Many of the compounds concerned end up in surface waters. Surface water quality is routinely monitored and numerous pesticides are found to be present in high concentrations, with various standards being regularly exceeded. Many standards-breaching pesticides exhibit regional patterns that can be traced back to land use. These patterns have been statistically analysed by correlating surface area per land use category with standards exceedance per pesticide, thereby identifying numerous significant correlations with respect to breaches of both the ecotoxicological standard (Maximum Tolerable Risk, MTR) and the drinking water standard. In the case of the MTR, greenhouse horticulture, floriculture and bulb-growing have the highest number as well as percentage of standard-breaching pesticides, despite these market segments being relatively small in terms of area cropped. Cereals, onions, vegetables, perennial border plants and pulses are also associated with many pesticides that exceed the drinking water standard. When a correction is made for cropped acreage, cereals and potatoes also prove to be a major contributor to monitoring sites where the MTR standard is exceeded. Over the period 1998-2006 the land-use categories with the most and highest percentage of standards-exceeding pesticides (greenhouse horticulture, bulb-growing and flower cultivation) showed an increase in the percentage of standards-exceeding compounds. PMID:23885409

  10. The Character of the Solar Wind, Surface Interactions, and Water

    NASA Technical Reports Server (NTRS)

    Farrell, William M.

    2011-01-01

    We discuss the key characteristics of the proton-rich solar wind and describe how it may interact with the lunar surface. We suggest that solar wind can be both a source and loss of water/OH related volatiles, and review models showing both possibilities. Energy from the Sun in the form of radiation and solar wind plasma are in constant interaction with the lunar surface. As such, there is a solar-lunar energy connection, where solar energy and matter are continually bombarding the lunar surface, acting at the largest scale to erode the surface at 0.2 Angstroms per year via ion sputtering [1]. Figure 1 illustrates this dynamically Sun-Moon system.

  11. Determination of antibiotic residues in manure, soil, and surface waters

    USGS Publications Warehouse

    Christian, T.; Schneider, R.J.; Farber, H.A.; Skutlarek, D.; Meyer, M.T.; Goldbach, H.E.

    2003-01-01

    In the last years more and more often detections of antimicrobially active compounds ("antibiotics") in surface waters have been reported. As a possible input pathway in most cases municipal sewage has been discussed. But as an input from the realm of agriculture is conceivable as well, in this study it should be investigated if an input can occur via the pathway application of liquid manure on fields with the subsequent mechanisms surface run-off/interflow, leaching, and drift. For this purpose a series of surface waters, soils, and liquid manures from North Rhine-Westphalia (Northwestern Germany) were sampled and analyzed for up to 29 compounds by HPLC-MS/MS. In each of the surface waters antibiotics could be detected. The highest concentrations were found in samples from spring (300 ng/L of erythromycin). Some of the substances detected (e.g., tylosin), as well as characteristics in the landscape suggest an input from agriculture in some particular cases. In the investigation of different liquid manure samples by a fast immunoassay method sulfadimidine could be detected in the range of 1...2 mg/kg. Soil that had been fertilized with this liquid manure showed a content of sulfadimidine extractable by accelerated solvent extraction (ASE) of 15 ??g/kg dry weight even 7 months after the application. This indicates the high stability of some antibiotics in manure and soil.

  12. Adsorption of ethanol and water on calcite: dependence on surface geometry and effect on surface behavior.

    PubMed

    Keller, K S; Olsson, M H M; Yang, M; Stipp, S L S

    2015-04-01

    Molecular dynamics (MD) simulations were used to explore adsorption on calcite, from a 1:1 mixture of ethanol and water, on planar {10.4} and stepped, i.e. vicinal, surfaces. Varying the surface geometry resulted in different adsorption patterns, which would directly influence the ability of ethanol to control calcite crystal growth, dissolution, and adsorption/desorption of other ions and molecules. Ethanol forms a well-ordered adsorbed layer on planar faces and on larger terraces, such as between steps and defects, providing little chance for water, with its weaker attachment, to displace it. However, on surfaces with steps, adsorption affinity depends on the length of the terraces between the steps. Long terraces allow ethanol to form a well-ordered, hydrophobic layer, but when step density is high, ethanol adsorption is less ordered, allowing water to associate at and near the steps and even displacing pre-existing ethanol. Water adsorbed at steps forms mass transport pathways between the bulk solution and the solid surface. Our simulations confirm the growth inhibiting properties of ethanol, also explaining how certain crystal faces are more stabilized because of their surface geometry. The -O(H) functional group on ethanol forms tight bonds with calcite; the nonpolar, -CH3 ends, which point away from the surface, create a hydrophobic layer that changes surface charge, thus wettability, and partly protects calcite from precipitation and dissolution. These tricks could easily be adopted by biomineralizing organisms, allowing them to turn on and off crystal growth. They undoubtedly also play a role in the wetting properties of mineral surfaces in commercial CaCO3 manufacture, oil production, and contamination remediation. PMID:25790337

  13. Near-field Oblique Remote Sensing of Stream Water-surface Elevation, Slope, and Surface Velocity

    NASA Astrophysics Data System (ADS)

    Minear, J. T.; Kinzel, P. J.; Nelson, J. M.; McDonald, R.; Wright, S. A.

    2014-12-01

    A major challenge for estimating discharges during flood events or in steep channels is the difficulty and hazard inherent in obtaining in-stream measurements. One possible solution is to use near-field remote sensing to obtain simultaneous water-surface elevations, slope, and surface velocities. In this test case, we utilized Terrestrial Laser Scanning (TLS) to remotely measure water-surface elevations and slope in combination with surface velocities estimated from particle image velocimetry (PIV) obtained by video-camera and/or infrared camera. We tested this method at several sites in New Mexico and Colorado using independent validation data consisting of in-channel measurements from survey-grade GPS and Acoustic Doppler Current Profiler (ADCP) instruments. Preliminary results indicate that for relatively turbid or steep streams, TLS collects tens of thousands of water-surface elevations and slopes in minutes, much faster than conventional means and at relatively high precision, at least as good as continuous survey-grade GPS measurements. Estimated surface velocities from this technique are within 15% of measured velocity magnitudes and within 10 degrees from the measured velocity direction (using extrapolation from the shallowest bin of the ADCP measurements). Accurately aligning the PIV results into Cartesian coordinates appears to be one of the main sources of error, primarily due to the sensitivity at these shallow oblique look angles and the low numbers of stationary objects for rectification. Combining remotely-sensed water-surface elevations, slope, and surface velocities produces simultaneous velocity measurements from a large number of locations in the channel and is more spatially extensive than traditional velocity measurements. These factors make this technique useful for improving estimates of flow measurements during flood flows and in steep channels while also decreasing the difficulty and hazard associated with making measurements in these conditions.

  14. Utilizing an Automated Home-Built Surface Plasmon Resonance Apparatus to Investigate How Water Interacts with a Hydrophobic Surface

    NASA Astrophysics Data System (ADS)

    Poynor, Adele

    2011-03-01

    By definition hydrophobic substances hate water. Water placed on a hydrophobic surface will form a drop in order to minimize its contact area. What happens when water is forced into contact with a hydrophobic surface? One theory is that an ultra-thin low- density region forms near the surface. We have employed an automated home-built Surface Plasmon Resonance (SPR) apparatus to investigate this boundary.

  15. MAIC-2, a latitudinal model for the Martian surface temperature, atmospheric water transport and surface glaciation

    NASA Astrophysics Data System (ADS)

    Grieger, Bjoern; Greve, Ralf; Stenzel, Oliver

    The Mars Atmosphere-Ice Coupler MAIC-2 is a simple, latitudinal model, which consists of a set of parameterisations for the surface temperature, the atmospheric water transport and the surface mass balance (condensation minus evaporation) of water ice. It is driven directly by the orbital parameters obliquity, eccentricity and solar longitude (Ls ) of perihelion. Surface temperature is described by the Local Insolation Temperature (LIT) scheme, which uses a daily and latitude-dependent radiation balance. The evaporation rate of water is calculated by an expression for free convection, driven by density differences between water vapor and ambient air, the condensation rate follows from the assumption that any water vapour which exceeds the local saturation pressure condenses instantly, and atmospheric transport of water vapour is approximated by instantaneous mixing. Glacial flow of ice deposits is neglected. Simulations with constant orbital parameters show that low obliquities favour deposition of ice in high latitudes and vice versa. A transient scenario driven by a computed history of orbital parameters over the last 10 million years produces essentially monotonically growing polar ice deposits during the most recent 4 million years, and a very good agreement with the observed present-day polar layered deposits. The thick polar deposits sometimes continue in thin ice deposits which extend far into the mid latitudes, which confirms the idea of "ice ages" at high obliquity.

  16. The Whitham Equation as a Model for Surface Water Waves

    E-print Network

    Daulet Moldabayev; Henrik Kalisch; Denys Dutykh

    2014-10-30

    The Whitham equation was proposed as an alternate model equation for the simplified description of uni-directional wave motion at the surface of an inviscid fluid. As the Whitham equation incorporates the full linear dispersion relation of the water wave problem, it is thought to provide a more faithful description of shorter waves of small amplitude than traditional long wave models such as the KdV equation. In this work, we identify a scaling regime in which the Whitham equation can be derived from the Hamiltonian theory of surface water waves. The Whitham equation is integrated numerically, and it is shown that the equation gives a close approximation of inviscid free surface dynamics as described by the Euler equations. The performance of the Whitham equation as a model for free surface dynamics is also compared to two standard free surface models: the KdV and the BBM equation. It is found that in a wide parameter range of amplitudes and wavelengths, the Whitham equation performs on par with or better than both the KdV and BBM equations.

  17. Dynamics of microdroplets over the surface of hot water

    E-print Network

    Takahiro Umeki; Masahiko Ohata; Hiizu Nakanishi; Masatoshi Ichikawa

    2015-01-03

    When drinking a cup of coffee under the morning sunshine, you may notice white membranes of steam floating on the surface of the hot water. They stay notably close to the surface and appear to almost stick to it. Although the membranes whiffle because of the air flow of rising steam, peculiarly fast splitting events occasionally occur. They resemble cracking to open slits approximately 1 mm wide in the membranes, and leave curious patterns. We studied this phenomenon using a microscope with a high-speed video camera and found intriguing details: i) the white membranes consist of fairly monodispersed small droplets of the order of 10 $\\mu\\,{\\rm m}$; ii) they levitate above the water surface by 10$\\sim$100 $\\mu{\\rm m}$; iii) the splitting events are a collective disappearance of the droplets, which propagates as a wave front of the surface wave with a speed of 1$\\sim$2 m/s; and iv) these events are triggered by a surface disturbance, which results from the disappearance of a single droplet.

  18. Water resources data, Wyoming, water year 2004; Volume 1. Surface water; with List of discontinued and active surface-water, water-quality, sediment, and biological stations

    USGS Publications Warehouse

    Watson, K.R.; Woodruff, R.E.; Laidlaw, G.A.; Clark, M.L.; Miller, K.A.

    2005-01-01

    Water resources data for the 2004 water year for Wyoming consist of records of stage, discharge and water quality of streams; stage and contents of lakes and reservoirs, and water levels and water quality of ground water. Volume 1 of this report contains discharge records for 164 gaging stations; water quality for 43 gaging stations and 45 ungaged stations, and stage and contents for one reservoir. Volume 2 of this report contains water levels records for 64 wells. Additional water data were collected at various sites, not part of the systematic data collection program, and are published as miscellaneous measurements. These data represent part of the National Water Information System operated by the U.S. Geological Survey and cooperating State and Federal agencies in Wyoming.

  19. Phosphorus: A Rate Limiting Nutrient in Surface Waters

    Microsoft Academic Search

    D. L. Correll

    ABSTRACT Phosphorus,is an essential element,for all life forms. It is a mineral,nutrient. Orthophosphate,is the only form,of P that autotrophs,can assimilate. Extracel- lular enzymes,hydrolyze,organic,forms,of P to phos- phate. Eutrophication,is the over-enrichment,of surface waters,with mineral,nutrients. The results are excessive production of autotrophs, especially algae and cyanobacteria.,This high,productivity,leads,to,high bacterial populations and high respiration rates, leading to hypoxia,or anoxia in poorly,mixed,bottom,waters,and at night in

  20. The surface composition of Charon - Tentative identification of water ice

    NASA Astrophysics Data System (ADS)

    Marcialis, R. L.; Rieke, G. H.; Lebofsky, L. A.

    1987-09-01

    The 3 March 1987 Charon occultation by Pluto was observed in the infrared at 1.5, 1.7, 2.0, and 2.35 micrometers. Subtraction of fluxes measured between second and third contacts from measurements made before and after the event has yielded individual spectral signatures for each body at these wavelengths. Charon's surface appears depleted in methane relative to Pluto. Constancy of flux at 2.0 micrometers throughout the event shows that Charon is effectively black at this wavelength, which is centered on a very strong water absorption band. Thus, the measurements suggest the existence of water ice on Pluto's moon.

  1. Soil Moisture: The Hydrologic Interface Between Surface and Ground Waters

    NASA Technical Reports Server (NTRS)

    Engman, Edwin T.

    1997-01-01

    A hypothesis is presented that many hydrologic processes display a unique signature that is detectable with microwave remote sensing. These signatures are in the form of the spatial and temporal distributions of surface soil moisture. The specific hydrologic processes that may be detected include groundwater recharge and discharge zones, storm runoff contributing areas, regions of potential and less than potential evapotranspiration (ET), and information about the hydrologic properties of soils. In basin and hillslope hydrology, soil moisture is the interface between surface and ground waters.

  2. Multiple sources of boron in urban surface waters and groundwaters.

    PubMed

    Hasenmueller, Elizabeth A; Criss, Robert E

    2013-03-01

    Previous studies attribute abnormal boron (B) levels in streams and groundwaters to wastewater and fertilizer inputs. This study shows that municipal drinking water used for lawn irrigation contributes substantial non-point loads of B and other chemicals (S-species, Li, and Cu) to surface waters and shallow groundwaters in the St. Louis, Missouri, area. Background levels and potential B sources were characterized by analysis of lawn and street runoff, streams, rivers, springs, local rainfall, wastewater influent and effluent, and fertilizers. Urban surface waters and groundwaters are highly enriched in B (to 250?g/L) compared to background levels found in rain and pristine, carbonate-hosted streams and springs (<25?g/L), but have similar concentrations (150 to 259?g/L) compared to municipal drinking waters derived from the Missouri River. Other data including B/SO4(2-)-S and B/Li ratios confirm major contributions from this source. Moreover, sequential samples of runoff collected during storms show that B concentrations decrease with increased discharge, proving that elevated B levels are not primarily derived from combined sewer overflows (CSOs) during flooding. Instead, non-point source B exhibits complex behavior depending on land use. In urban settings B is rapidly mobilized from lawns during "first flush" events, likely representing surficial salt residues from drinking water used to irrigate lawns, and is also associated with the baseflow fraction, likely derived from the shallow groundwater reservoir that over time accumulates B from drinking water that percolates into the subsurface. The opposite occurs in small rural watersheds, where B is leached from soils by recent rainfall and covaries with the event water fraction. PMID:23384647

  3. Internal distribution of Cd in lettuce and resulting effects on Cd trophic transfer to the snail: Achatina fulica.

    PubMed

    Li, Cheng-Cheng; Dang, Fei; Cang, Long; Zhou, Dong-Mei; Peijnenburg, Willie J G M

    2015-09-01

    The mechanisms underlying Cd trophic transfer along the soil-lettuce-snail food chain were investigated. The fate of Cd within cells, revealed by assessment of Cd chemical forms and of subcellular partitioning, differed between the two examined lettuce species that we examined (L. longifolia and L. crispa). The species-specific internal Cd fate not only influenced Cd burdens in lettuce, with higher Cd levels in L. crispa, but also affected Cd transfer efficiency to the consumer snail (Achatina fulica). Especially, the incorporation of Cd chemical forms (Cd in the inorganic, water-soluble and pectates and protein-integrated forms) in lettuce could best explain Cd trophic transfer, when compared to dietary Cd levels alone and/or subcellular Cd partitioning. Trophically available metal on the subcellular partitioning base failed to shed light on Cd transfer in this study. After 28-d of exposure, most Cd was trapped in the viscera of Achatina fulica, and cadmium bio-magnification was noted in the snails, as the transfer factor of lettuce-to-snail soft tissue was larger than one. This study provides a first step to apply a chemical speciation approach to dictate the trophic bioavailability of Cd through the soil-plant-snail system, which might be an important pre-requisite for mechanistic understanding of metal trophic transfer. PMID:25930053

  4. Physiological and biochemical responses to cold and drought in the rock-dwelling pulmonate snail, Chondrina avenacea.

    PubMed

    Koštál, Vladimír; Rozsypal, Jan; Pech, Pavel; Zahradní?ková, Helena; Šimek, Petr

    2013-08-01

    The pulmonate snail Chondrina avenacea lives on exposed rock walls where it experiences drastic daily and seasonal fluctuations of abiotic conditions and food availability. We found that tolerance to dry conditions was maintained at a very high level throughout the year and was mainly based on the snails' ability to promptly enter into estivation (quiescence) whenever they experienced drying out of their environment. Snails rapidly suppressed their metabolism and minimized their water loss using discontinuous gas exchange pattern. The metabolic suppression probably included periods of tissue hypoxia and anaerobism as indicated by accumulation of typical end products of anaerobic metabolism: lactate, alanine and succinate. Though the drought-induced metabolic suppression was sufficient to stimulate moderate increase of supercooling capacity, the seasonally highest levels of supercooling capacity and the highest tolerance to subzero temperatures were tightly linked to hibernation (diapause). Hibernating snails did not survive freezing of their body fluids and instead relied on supercooling strategy which allowed them to survive when air temperatures dropped to as low as -21 °C. No accumulation of low-molecular weight compounds (potential cryoprotectants) was detected in hibernating snails except for small amounts of the end products of anaerobic metabolism. PMID:23516021

  5. Impact of river restoration on groundwater - surface water - interactions

    NASA Astrophysics Data System (ADS)

    Kurth, Anne-Marie; Schirmer, Mario

    2014-05-01

    Since the end of the 19th century, flood protection was increasingly based on the construction of impermeable dams and side walls (BWG, 2003). In spite of providing flood protection, these measures also limited the connectivity between the river and the land, restricted the area available for flooding, and hampered the natural flow dynamics of the river. Apart from the debilitating effect on riverine ecosystems due to loss of habitats, these measures also limited bank filtration, inhibited the infiltration of storm water, and affected groundwater-surface water-interactions. This in turn had a profound effect on ecosystem health, as a lack of groundwater-surface water interactions led to decreased cycling of pollutants and nutrients in the hyporheic zone and limited the moderation of the water temperature (EA, 2009). In recent decades, it has become apparent that further damages to riverine ecosystems must be prohibited, as the damages to ecology, economy and society surmount any benefits gained from exploiting them. Nowadays, the restoration of rivers is a globally accepted means to restore ecosystem functioning, protect water resources and amend flood protection (Andrea et al., 2012; Palmer et al., 2005; Wortley et al., 2013). In spite of huge efforts regarding the restoration of rivers over the last 30 years, the question of its effectiveness remains, as river restorations often reconstruct a naturally looking rather than a naturally functioning stream (EA, 2009). We therefore focussed our research on the effectiveness of river restorations, represented by the groundwater-surface water-interactions. Given a sufficiently high groundwater level, a lack of groundwater-surface water-interactions after restoration may indicate that the vertical connectivity in the stream was not fully restored. In order to investigate groundwater-surface water-interactions we determined the thermal signature on the stream bed and in +/- 40 cm depth by using Distributed Temperature Sensing (DTS), a fibre optical method for temperature determination over long distances (Selker et al., 2006). Thermal signatures were determined in a small urban stream before and after restoration and compared to streams in natural and near-natural settings. BWG BUNDESAMT FÜR WASSER UND GEOLOGIE, 2003. Die Geschichte des Hochwasserschutzes in der Schweiz. Bericht des BWG, Serie Wasser. Biel. 208 p. EA ENVIRONMENT AGENCY (UK), 2009. The Hyporheic Handbook: A handbook on the groundwater-surface water interface and hyporheic zone for environment managers. Bristol. 280 p. ANDREA, F., GSCHÖPF, C., BLASCHKE, A.P., WEIGELHOFER, G., AND RECKENDORFER, W., 2012. Ecological niche models for the evaluation of management options in urban floodplain - conservation vs. restoration purposes. Environ. Sci. Policy, http://dx.doi.org/10.1016/j.envsci.2012.08.011. PALMER, M.A., BERNHARDT, E.S., ALLAN, J.D., LAKE, P.S., ALEXANDER, G., BROOKS, S., CARR, J., CLAYTON, S., DAHM, C.N., FOLLSTAD SHAH, J., GALAT, D.L., LOSS, S.G., GOODWIN, P., HART, D.D., HASSETT, B., JENKINSON, R., KONDOLF, G.M., LAVE, R., MEYER, J.L., O`DONNELL, T.K., PAGANO, L. AND SUDDUTH, E., 2005. Standards for ecologically successful river restoration. Journal of Applied Ecology, 42, pp. 208 - 217. DOI 10.1111/j.1365-2664.2005.01004.x. WORTLEY, L., HERO, J-M., HOWES, M., 2013. Evaluating Ecological Restoration Success: A Review of the Literature. Restoration Ecology, 21 (5), pp. 537 - 543. DOI 10.1111/rec.12028. SELKER, J.S., THEVENAZ, L., HUWALD, H., MALLET, A., LUXEMBURG, W., VAN DE GIESEN, N., STEJSKAL, M., ZEMAN, J., WESTHOFF, M., AND PARLANGE, M.B., 2006. Distributed fibre-optic temperature sensing for hydrologic systems. Water Resources Research, 42(12), W12202.

  6. Surface Water Quality as Affected by Sugarcane Residue Management Techniques

    Microsoft Academic Search

    Theophilus K. Udeigwe; Jim J. Wang; Howard P. Viator; Lewis Gaston

    2010-01-01

    This study evaluated the impacts of three sugarcane residue management techniques, namely postharvest burning of residue (BR),\\u000a shredding of residue (SR), and full postharvest retention of residue (RR), on the water quality of surface runoff from February\\u000a 2006 to September 2007 in Iberia, LA. Total runoff volumes recorded were 58,418, 57,923, and 46,578 L for the BR, SR, and\\u000a RR treatments,

  7. Numerical Modeling of Ozonation of Organic Chemicals in Surface Water

    Microsoft Academic Search

    Tingting Zhu; Yafei Jia; Ajit Sadana; Sam S. Y. Wang

    Ozonation of organic chemicals generally can result in less toxic and more bio- degradable products. It is proposed to use ozone as a potential decontaminant in case of chemical spill in surface waters. CCHE2D chemical model, a two-dimensional depth-averaged and process-based chemical fate and transport model, was developed for simulating multiple decontamination tests including two-chemical-reaction processes. In this study, toluene

  8. Surface water risk assessment of pesticides in Ethiopia.

    PubMed

    Teklu, Berhan M; Adriaanse, Paulien I; Ter Horst, Mechteld M S; Deneer, John W; Van den Brink, Paul J

    2015-03-01

    Scenarios for future use in the pesticide registration procedure in Ethiopia were designed for 3 separate Ethiopian locations, which are aimed to be protective for the whole of Ethiopia. The scenarios estimate concentrations in surface water resulting from agricultural use of pesticides for a small stream and for two types of small ponds. Seven selected pesticides were selected since they were estimated to bear the highest risk to humans on the basis of volume of use, application rate and acute and chronic human toxicity, assuming exposure as a result of the consumption of surface water. Potential ecotoxicological risks were not considered as a selection criterion at this stage. Estimates of exposure concentrations in surface water were established using modelling software also applied in the EU registration procedure (PRZM and TOXSWA). Input variables included physico-chemical properties, and data such as crop calendars, irrigation schedules, meteorological information and detailed application data which were specifically tailored to the Ethiopian situation. The results indicate that for all the pesticides investigated the acute human risk resulting from the consumption of surface water is low to negligible, whereas agricultural use of chlorothalonil, deltamethrin, endosulfan and malathion in some crops may result in medium to high risk to aquatic species. The predicted environmental concentration estimates are based on procedures similar to procedures used at the EU level and in the USA. Addition of aquatic macrophytes as an ecotoxicological endpoint may constitute a welcome future addition to the risk assessment procedure. Implementation of the methods used for risk characterization constitutes a good step forward in the pesticide registration procedure in Ethiopia. PMID:25481716

  9. Changes in chemical components in the freshwater apple snail, Pomacea canaliculata (Gastropoda: Ampullariidae), in relation to the development of its cold hardiness.

    PubMed

    Matsukura, Keiichiro; Tsumuki, Hisaaki; Izumi, Yohei; Wada, Takashi

    2008-04-01

    The apple snail, Pomacea canaliculata, is an invasive freshwater snail. It increases its cold hardiness before winter. However, the physiological mechanism of cold hardiness in molluscs is poorly understood, especially in freshwater molluscs. In this study, we examined the changes in low molecular weight compounds, glycogen and lipids, in the body of P. canaliculata in association with the development of cold hardiness. When snails without cold hardiness were experimentally cold-acclimated, the amount of glycerol, glutamine, and carnosine increased, while glycogen and phenylalanine decreased. Overwintering cold-tolerant snails collected from a drained paddy field in November also showed increased glycerol in their bodies with decreasing glycogen concentration, compared to summer snails collected from a submerged field. Water content also decreased during the cold acclimation, although the water loss was minimal. These results indicate that the freshwater snail, P. canaliculata enhances cold hardiness by accumulation of some kinds of low molecular weight compounds in its body as some insects do. However, the actual function of each low molecular compound is still unknown. PMID:18190902

  10. The effects of the herbicide atrazine on freshwater snails.

    PubMed

    Gustafson, Kyle D; Belden, Jason B; Bolek, Matthew G

    2015-07-01

    Atrazine has been shown to affect freshwater snails from the subcellular to community level. However, most studies have used different snail species, methods, endpoints, and atrazine exposure concentrations, resulting in some conflicting results and limiting our understanding. The goal of this study was to address these concerns by (1) investigating the acute and chronic effects of atrazine on four species of freshwater snails (Biomphalaria glabrata, Helisoma trivolvis, Physa acuta, and Stagnicola elodes) using the same methods, endpoints, and concentrations, and (2) summarizing the current literature pertaining to the effects of atrazine on freshwater snails. We conducted a 48 h acute toxicity test with an atrazine concentration higher than what typically occurs in aquatic environments (1000 µg/L). Additionally, we exposed snails to environmentally relevant atrazine concentrations (0, 0.3, 3, and 30 µg/L) for 28 days and assessed snail survival, growth, and reproduction. We also summarized all known literature pertaining to atrazine effects on freshwater snails. The literature summary suggests snails are often affected by environmentally relevant atrazine concentrations at the subcellular and cellular levels. These effects are typically not transitive to effects on survival, growth, or reproduction at the same concentrations. Our acute exposures corroborate the general trend of no direct effect on snail populations as atrazine did not directly affect the survival of any of the four snail species. Similarly, environmentally relevant concentrations did not significantly affect the survival, growth, or reproduction of any snail species. These results indicate that, in the absence of other possible stressors, the direct effects of environmentally relevant atrazine concentrations may not be realized at the snail population level. PMID:25971234

  11. Nitrate impacts on the Florida apple snail, Pomacea paludosa

    Microsoft Academic Search

    Norah Myers Corrao; Philip C. Darby; Christopher M. Pomory

    2006-01-01

    Nitrate pollution in springs in Florida has been suggested as a possible reason for declining populations of the Florida apple\\u000a snail, Pomacea paludosa (Say). No correlation was found between snail density and nitrate concentration measured in six Florida springs. In laboratory\\u000a studies examining short-term acute impacts of nitrate, adult and juvenile snail 96 h LC50 values could not be determined due

  12. Stable isotope values of Costa Rican surface waters

    NASA Astrophysics Data System (ADS)

    Lachniet, Matthew S.; Patterson, William P.

    2002-03-01

    Stable isotope data of surface waters from the humid tropics in general, and Costa Rica in particular, are scarce. To improve our understanding of the spatial distribution of stable isotopes in surface waters, we measured ?18O and ?D in river and lake ( n=63) and precipitation ( n=3) samples from Costa Rica. We also present data from the IAEA/WMO isotopes in precipitation network as context for our study. Surface water isotope values do not strongly correlate with elevation, stream head elevation, stream length, distance from Caribbean Sea, or estimated mean annual precipitation for the country as a whole. However, the data show distinct regional trends. The ?18O and ?D values downwind of mountain ranges are inversely related to the altitude of the ranges the air masses traverse. In the lee of the high Talamanca Range, ?18O values are ˜6-8‰ lower, while in the lee of the lower Tilarán Range ?18O values are 2-3‰ lower than upwind sites along the Caribbean Slope. An altitude effect of -1.4‰ ?18O/km is present on the Pacific slope of southern Costa Rica, equivalent to a temperature effect of -0.3‰/°C. The Nicoya and Osa Peninsulas have higher values than upwind sites, suggesting input of Pacific-sourced moisture, evaporative enrichment, or decreased condensation temperatures. Elevated and increasing d-excess values inland along the Nicaragua Trough suggest a recycled component may be an important contributor to the water budget. These data provide preliminary stable isotope information for Costa Rica, and will benefit paleoclimatic research in the region. More detailed studies would be beneficial to our understanding of the controls on stable isotope composition of tropical waters.

  13. Nitrate reducing activity pervades surface waters during upwelling

    NASA Astrophysics Data System (ADS)

    Fernandes, Sheryl Oliveira; Halarnekar, Reena; Malik, Ashish; Vijayan, Vijitha; Varik, Sandesh; Kumari, Ritu; V. K., Jineesh; Gauns, Manguesh U.; Nair, Shanta; LokaBharathi, P. A.

    2014-09-01

    Nitrate reducing activity (NRA) is known to be mediated by microaerophilic to anaerobic bacteria and generally occurs in the sub-surface waters. However, we hypothesize that NRA could become prominent in the surface waters during upwelling. Hence, we examined nitrification and nitrate reduction along with hydrographic and environmental parameters off Trivandrum and Kochi, south-west-India in June 2010. Shoaling isolines of temperature, density, and nutrients revealed the onset of upwelling off Trivandrum. Shoaling of these signatures was absent in the northern transect off Kochi. The degree of nutrient consumption (DNC) was low emphasizing the presence of newly upwelled water off Trivandrum. A significant increase in NRA (df = 1, p < 0.05) was observed off Trivandrum than at Kochi. Moreover, as hypothesized, NRA at Trivandrum was pronounced at the surface with a maximum rate of 0.85 (± 0.02) ?mol L1 h- 1 nearshore which was ~ 29 × higher than that at Kochi. Further, an inverse relationship between NRA and NO3- concentration (n = 34, r = - 0.415, p < 0.01) suggested transformation of the upwelled nutrient. Nitrification/NRA was ~ 10 × lower at 0.28 off Trivandrum indicating a discernible shift towards reduction. Such contribution from bacterial activity could be a response towards restoration of homeostasis.

  14. ERTS imagery applied to Alaskan coastal problems. [surface water circulation

    NASA Technical Reports Server (NTRS)

    Wright, F. F.; Sharma, G. D.; Burbank, D. C.; Burns, J. J.

    1974-01-01

    Along the Alaska coast, surface water circulation is relatively easy to study with ERTS imagery. Highly turbid river water, sea ice, and fluvial ice have proven to be excellent tracers of the surface waters. Sea truth studies in the Gulf of Alaska, Cook Inlet, Bristol Bay, and the Bering Strait area have established the reliability of these tracers. ERTS imagery in the MSS 4 and 5 bands is particularly useful for observing lower concentrations of suspended sediment, while MSS 6 data is best for the most concentrated plumes. Ice features are most clearly seen on MSS 7 imagery; fracture patterns and the movement of specific floes can be used to map circulation in the winter when runoff is restricted, if appropriate allowance is made for wind influence. Current patterns interpreted from satellite data are only two-dimensional, but since most biological activity and pollution are concentrated near the surface, the information developed can be of direct utility. Details of Alaska inshore circulation of importance to coastal engineering, navigation, pollution studies, and fisheries development have been clarified with satellite data. ERTS has made possible the analysis of circulation in many parts of the Alaskan coast.

  15. Remote surface water monitoring radio based telemetry system

    NASA Astrophysics Data System (ADS)

    Goodwin, W. L.; Baxter, D.

    1993-02-01

    The Environmental Protection Department of EG&G Rocky Flats has designed and developed a unique Remote Surface Water Monitoring System using radio telemetry hardware and computer control software. The system is based on new technologies in microelectronics and environmental monitoring sensors. An engineering team, headed up by the Surface Water Division at EG&G, has proven that with careful evaluation of new technologies and hardware components, a reliable, cost effective and graphical user interface (GUI) system can be designed and installed. The network utilizes standard industrial control hardware and off-the-shelf components in order to meet several time requirements outlined by an Interagency Agreement (IAG) between the Department of Energy, the U.S. Environmental Protection Agency, and state and local authorities. In addition, the system had to meet tight environmental specifications and procedures. The Rocky Flats Plant is part of the U.S. Department of Energy Weapons Complex and is located near the Denver metropolitan area. The plant is required by law, and Interagency Agreement, to maintain strict environmental standards for surface water monitoring and discharge characteristics, including the requirement for utilization of best available technology.

  16. Effective modification of particle surface properties using ultrasonic water mist.

    PubMed

    Genina, Natalja; Räikkönen, Heikki; Heinämäki, Jyrki; Antikainen, Osmo; Siiriä, Simo; Veski, Peep; Yliruusi, Jouko

    2009-01-01

    The goal of the present study was to design a new technique to modify particle surface properties and, through that, to improve flowability of poorly flowing drug thiamine hydrochloride and pharmaceutical sugar lactose monohydrate of two different grades. The powdered particles were supplied by a vibratory feeder and exposed to an instantaneous effect of water mist generated from an ultrasound nebulizer. The processed and original powders were evaluated with respect to morphology (scanning electron microscopy, atomic force microscopy, and spatial filtering technique), flow, and solid state properties. It was found that rapid exposition of pharmaceutical materials by water mist resulted in the improvement of powder technical properties. The evident changes in flowability of coarser lactose were obviously due to smoothing of particle surface and decreasing in the level of fines with very slight increment in particle size. The changes in thiamine powder flow were mainly due to narrowing in particle size distribution where the tendency for better flow of finer lactose was related to surface and size modifications. The aqueous mist application did not cause any alteration of the crystal structures of the studied materials. The proposed water mist treatment technique appears to be a robust, rapid, and promising tool for the improvement of the technological properties of pharmaceutical powders. PMID:19288203

  17. Polyfluorinated compounds in waste water treatment plant effluents and surface waters along the River Elbe, Germany

    Microsoft Academic Search

    Lutz Ahrens; Sebastian Felizeter; Renate Sturm; Zhiyong Xie; Ralf Ebinghaus

    2009-01-01

    Polyfluorinated compounds (PFCs) were investigated in waste water treatment plant (WWTP) effluents and surface waters of the River Elbe from samples collected in 2007. Concentrations of various PFCs, including C4–C8 perfluorinated sulfonates (PFSAs), C6 and C8 perfluorinated sulfinates, 6:2 fluorotelomer sulfonate, C5–C13 perfluorinated carboxylic acids (PFCAs), C4 and C8 perfluoroalkyl sulfonamides and 6:2, 8:2 and 10:2 unsaturated fluorotelomercarboxylic acids were

  18. SURFACE WATER AND GROUND WATER QUALITY MONITORING FOR RESTORATION OF URBAN LAKES IN GREATER HYDERABAD, INDIA

    Microsoft Academic Search

    A. K. Mohanty

    2009-01-01

    SURFACE WATER AND GROUND WATER QUALITY MONITORING FOR RESTORATION OF URBAN LAKES IN GREATER HYDERABAD, INDIA A.K. Mohanty, K. Mahesh Kumar, B. A. Prakash and V.V.S. Gurunadha Rao Ecology and Environment Group National Geophysical Research Institute, (CSIR) Hyderabad - 500 606, India E-mail:atulyakumarmohanty@yahoo.com Abstract: Hyderabad Metropolitan Development Authority has taken up restoration of urban lakes around Hyderabad city under Green

  19. Mean surface water balance over Africa and its interannual variability

    SciTech Connect

    Nicholson, S.E.; Kim, J.; Ba, M.B. [Florida State Univ., Tallahassee, FL (United States)] [Florida State Univ., Tallahassee, FL (United States); Lare, A.R. [NASA/GSFC, Greenbelt, MD (United States)] [NASA/GSFC, Greenbelt, MD (United States)

    1997-12-01

    This article presents calculations of surface water balance for the African continent using a revised version of the Lettau climatonomy. Calculations are based on approximately 1400 rainfall stations, with records generally covering 60 yr or longer. Continental maps of evapotranspiration. runoff, and soil moisture are derived for January, July, and the annual mean. The model is also used to provide a gross estimate of the interannual variability of these parameters over most of the continent and local water balance calculations for a variety of locations in Africa. The results are compared with four other comprehensive global water balance studies. The results of this study are being used to produce a gridded dataset for the continent, with potential applications for numerical modeling studies. 50 refs., 18 figs., 3 tabs.

  20. Evaporating behaviors of water droplet on superhydrophobic surface

    NASA Astrophysics Data System (ADS)

    Hao, PengFei; Lv, CunJing; He, Feng

    2012-12-01

    We investigated the dynamic evaporating behaviors of water droplet on superhydrophobic surfaces with micropillars. Our experimental data showed that receding contact angles of the water droplet increased with the decreasing of the scale of the micropillars during evaporation, even though the solid area fractions of the microstructured substrates remained constant. We also experimentally found that the critical contact diameters of the transition between the Cassie-Baxter and Wenzel states are affected not only by the geometrical parameters of the microstructures, but also by the initial volume of the water droplet. The measured critical pressure is consistent with the theoretical model, which validated the pressure-induced impalement mechanism for the wetting state transition.

  1. Dry in the Water: The Superhydrophobic Water Fern Salvinia – a Model for Biomimetic Surfaces

    Microsoft Academic Search

    Zdenek Cerman; Boris F. Striffler; Wilhelm Barthlott

    Over millions of years plant surfaces evolved optimized complex multifunctional interfaces. They fulfill different functions\\u000a in terrestrial plants such as limitation of uncontrolled water loss, protection against various biotic and abiotic influences,\\u000a and they play a role in the attachment of insects. A recent overview on plant surface functions is presented by Jeffree (in\\u000a Riederer, 2006). One of the most

  2. The effect of antibiotic treatment on the supercooling ability of the land snail Helix aspersa (Gastropoda: Pulmonata).

    PubMed

    Ansart, Armelle; Vernon, Philippe; Charrier, Maryvonne; Daguzan, Jacques

    2002-04-01

    The land snail Helix aspersa is a partially freezing tolerant species whose supercooling ability is limited to ca. -3 to -5 degrees C. One hundred adult snails were subjected to the following two experimental conditions: (i) a starved group, provided with water; (ii) an antibiotic-treated group that was provided with a solution containing a mixture of two antibiotics. The antibiotic group exhibited a T(c) significantly lower than the starved group (-3.94 +/- 1.32 degrees C, n = 40 and -3.07 +/- 0.99, n = 30, t test, p < 0.005). This study showed that bacteria of the gut are likely to elevate animal supercooling points. It is also the first report in which a possible ice-nucleating activity of the gut microflora in a land snail has been suggested by the action of antibiotics on the T(c). PMID:12151274

  3. [Performance of treatment wetland systems for surface water quality improvement].

    PubMed

    Liu, Hong; Dai, Ming-li; Liu, Xue-yan; Ouyang, Wei; Liu, Pei-bin

    2004-07-01

    Intercropped with Phragmites communis and Typha angustifolia, subsurface flow constructed wetland systems (CWs) with the surface area of 3 x 20m x 2m were established beside Guanting Reservoir, an important source water base of Beijing. The treatment performance of the systems with different season were studied, the impacts of influent concentration, hydraulic loading rate and water temperature on contaminations removal were analyzed. The result showed that the subsurface flow CWs had the better decontamination effect to micro-pollution surface water. The relationship between the concentrations of CODMn and NH4+ -N in inflow and outflow followed the linear equation. The removal rates of total nitrogen (TN) and total phosphorus (TP) in the systems were 20%-60% and 30%-45%, respectively. The removal rates of contaminations were reduced with the decrease of water temperature and the increase of hydraulic loading rate, the removal rates of CODMn, N4+ -N and TN showed the positive correlation with their inflow concentration, but the removal rate of TP showed the negative correlation with its inflow concentration. Operation and management considerations of the subsurface flow CWs in winter were investigated in this study. PMID:15515938

  4. Reconnaissance of selected PPCP compounds in Costa Rican surface waters.

    PubMed

    Spongberg, Alison L; Witter, Jason D; Acuña, Jenaro; Vargas, José; Murillo, Manuel; Umaña, Gerardo; Gómez, Eddy; Perez, Greivin

    2011-12-15

    Eighty-six water samples were collected in early 2009 from Costa Rican surface water and coastal locations for the analysis of 34 pharmaceutical and personal care product compounds (PPCPs). Sampling sites included areas receiving treated and untreated wastewaters, and urban and rural runoff. PPCPs were analyzed using a combination of solid phase extraction and liquid chromatography tandem mass spectrometry. The five most frequently detected compounds were doxycycline (77%), sulfadimethoxine (43%), salicylic acid (41%), triclosan (34%) and caffeine (29%). Caffeine had the maximum concentration of 1.1 mg L(-1), possibly due to coffee bean production facilities upstream. Other compounds found in high concentrations include: doxycycline (74 ?g L(-1)), ibuprofen (37 ?g L(-1)), gemfibrozil (17 ?g L(-1)), acetominophen (13 ?g L(-1)) and ketoprofen (10 ?g L(-1)). The wastewater effluent collected from an oxidation pond had similar detection and concentrations of compounds compared to other studies reported in the literature. Waters receiving runoff from a nearby hospital showed higher concentrations than other areas for many PPCPs. Both caffeine and carbamazepine were found in low frequency compared to other studies, likely due to enhanced degradation and low usage, respectively. Overall concentrations of PPCPs in surface waters of Costa Rica are inline with currently reported occurrence data from around the world, with the exception of doxycycline. PMID:22048020

  5. Input dynamics of pesticide transformation products into surface water

    NASA Astrophysics Data System (ADS)

    Kern, Susanne; Singer, Heinz; Hollender, Juliane; Schwarzenbach, René P.; Fenner, Kathrin

    2010-05-01

    Some pesticide transformation products have been observed to occur in higher concentrations and more frequently than the parent active pesticide in surface water and groundwater. These products are often more mobile and sometimes more stable than the parent pesticide. If they also represent the major product into which the parent substance is transformed, these transformation products may dominate observed pesticide occurrences in surface water and groundwater. Their potential contribution to the overall risk to the aquatic environment caused by the use of the parent pesticide should therefore not be neglected in chemical risk and water quality assessments. The same is true for transformation products of other compound classes that might reach the soil environment, such as veterinary pharmaceuticals. However, the fate and input pathways of transformation products of soil-applied chemicals into surface water are not yet well understood, which largely prevents their appropriate inclusion into chemical risk and water quality assessments. Here, we studied whether prioritization methods based on available environmental fate data from pesticide registration dossiers in combination with basic fate models could help identify transformation products which can be found in relevant concentrations in surface and groundwater and which should therefore be included into monitoring programs. A three-box steady state model containing air, soil, and surface water compartments was used to predict relative inputs of pesticide transformation products into surface waters based on their physico-chemical and environmental fate properties. The model predictions were compared to monitoring data from a small Swiss river located in an intensely agricultural catchment (90 km2) which was flow-proportionally sampled from May to October 2008 and screened for 74 pesticides as well as 50 corresponding transformation products. Sampling mainly occurred during high discharge, but additional samples during baseflow conditions were also taken. The analytical measurements included solid phase extraction, liquid chromatography and high resolution mass spectrometry (SPE-LC-HR-MS/MS). Quantification was achieved using reference standards and internal standards. Besides the well-known transformation products of triazine and chloroacetanilide herbicides, transformation products of other compound classes such as azoxystrobin acid (from azoxystrobin, strobilurin fungicide), chloridazon-desphenyl and chloridazon-methyl-desphenyl (from chloridazon, pyridazinone herbicide), and metamitron-desamino (from metamitron, triazinone herbicide) were analyzed in surface water. For a selection of widely used pesticides in the catchment, modelled ratios of transformation product versus parent pesticide concentrations were compared to the measured concentration ratios in the river for the application period and for two 2-month periods following application. Concentration ratios agreed within a factor of 10 for all pairs of parent pesticides and transformation products, and for all seasons, with a single exception. The ratio of chloridazon-desphenyl to chloridazon was under-predicted by a factor of approximately 20. The data revealed that chloridazon-desphenyl was also found in elevated concentrations in all baseflow samples, indicating its presence in the groundwater component of the catchment. The same was true for other transformation products (e.g., metamitron-desamino, chloridazon-methly-desphenyl, metolachlor-ESA), but to a lesser degree. Based on baseflow separation of the hydrograph, the concentration ratio estimation model was supplemented with an additional baseflow component. The concentrations in the baseflow component were estimated with a simple leaching relationship that was compared against measured baseflow concentrations and groundwater findings in Switzerland. The final model yielded good agreement for all compounds and is therefore deemed suitable for prioritization of transformation products with a relevant exposure potential. It also clearly indicated the contr

  6. Fecundity of the Chinese mystery snail in a Nebraska reservoir

    USGS Publications Warehouse

    Stephen, Bruce J.; Allen, Craig R.; Chaine, Noelle M.; Fricke, Kent A.; Haak, Danielle M.; Hellman, Michelle L.; Kill, Robert A.; Nemec, Kristine T.; Pope, Kevin L.; Smeenk, Nicholas A.; Uden, Daniel R.; Unstad, Kody M.; VanderHam, Ashley E.; Wong, Alec

    2013-01-01

    The Chinese mystery snail (Bellamya chinensis) is a non-indigenous, invasive species in freshwater ecosystems of North America. We provide fecundity estimates for a population of these snails in a Nebraska reservoir. We dissected 70 snails, of which 29 were females. Nearly all female snails contained developing young, with an average of 25 young per female. Annual fecundity was estimated at between 27.2 and 33.3 young per female per year. Based on an estimated adult population and the calculated fecundity, the annual production for this reservoir was between 2.2 and 3.7 million young.

  7. Major carbon-14 deficiency in modern snail shells from southern Nevada springs

    SciTech Connect

    Riggs, A.C.

    1984-04-06

    Carbon-14 contents as low as 3.3 +/- 0.2% modern (apparent age, 27,000 years) measured from the shells of snails Melanoides tuberculatus living in artesian springs in southern Nevada are attributed to fixation of dissolved HCO/sub 3//sup -/ with which the shells are in carbon isotope equilibrium. Recognition of the existence of such extreme deficiencies is necessary so that erroneous ages are not attributed to fresh water biogenic carbonates. 2 figures, 1 table.

  8. Gametogenic cycle and size at first maturity of the Patagonic edible snail Buccinanops cochlidium from Argentina

    Microsoft Academic Search

    Andrés Averbuj; Gregorio Bigatti; Pablo E. Penchaszadeh

    2010-01-01

    Buccinanops cochlidium is a common edible snail from Argentinean shallow waters, which is being consumed locally in north Patagonia. Nevertheless,\\u000a there are no policies for their fisheries management. This study provides information about the reproductive cycle and size\\u000a at first maturity of B. cochlidium from San José Gulf, Argentina. In this species, the testes seemed to develop mature sperm all

  9. Groundwater surface water interaction study using natural isotopes tracer

    NASA Astrophysics Data System (ADS)

    Yoon, Yoon Yeol; Kim, Yong Chul; Cho, Soo Young; Lee, Kil Yong

    2015-04-01

    Tritium and stable isotopes are a component of the water molecule, they are the most conservative tracer for groundwater study. And also, radon is natural radioactive nuclide and well dissolved in groundwater. Therefore, these isotopes are used natural tracer for the study of surface water and groundwater interaction of water curtain greenhouse area. The study area used groundwater as a water curtain for warming tool of greenhouse during the winter, and is associated with issues of groundwater shortage while being subject to groundwater-river water interaction. During the winter time, these interactions were studied by using Rn-222, stable isotopes and H-3. These interaction was monitored in multi depth well and linear direction well of groundwater flow. And dam effect was also compared. Samples were collected monthly from October 2013 to April 2014. Radon and tritium were analyzed using Quantulus low background liquid scintillation counter and stable isotopes were analyzed using an IRIS (Isotope Ratio Infrared Spectroscopy ; L2120-i, Picarro). During the winter time, radon concentration was varied from 0.07 Bq/L to 8.9 Bq/L and different interaction was showed between dam. Surface water intrusion was severe at February and restored April when greenhouse warming was ended. The stable isotope results showed different trend with depth and ranged from -9.16 ‰ to -7.24 ‰ for ? 18O value, while the ?D value was ranged from -57.86 ‰ to -50.98 ‰. The groundwater age as dated by H-3 was ranged 0.23 Bq/L - 0.59 Bq/L with an average value of 0.37 Bq/L.

  10. Water resources data for Florida, water year 1992. Volume 1A. Northeast florida surface water. Water-data report (Annual), 1 October 1991-30 September 1992

    SciTech Connect

    Not Available

    1993-04-01

    Water resources data for 1992 water year for northeast Florida include continuous or daily discharge for 140 streams, periodic discharge for 10 streams, miscellaneous discharge for 14 streams, continuous or daily stage for 32 streams, continuous or daily tide stage for 3 sites, periodic stage for 23 streams, peak discharge for 3 stream, and peak stage for 11 streams; continuous or daily elevations for 36 lakes, periodic elevations for 47 lakes; continuous ground-water levels for 75 wells, periodic ground-water levels for 123 wells, and miscellaneous water-level measurements for 864 wells; quality-of-water data for 38 surface-water sites and 66 wells.

  11. Remote sensing of surface water for environmental flows

    NASA Astrophysics Data System (ADS)

    Tulbure, M. G.; Kingsford, R.; Lucas, R.; Keith, D.

    2013-12-01

    Environmental flows represent water management activities that release flushes of water stored in dams on regulated rivers during dry periods. These flows aim to mimic natural flow and inundation regimes to maintain ecological health and function of rivers and wetlands. Assessment and understanding of the effectiveness of environmental flows requires quantification of temporal and spatial pattern of surface water and inundation dynamic in a synoptic yet detailed way and understanding dynamics of vegetation response to flooding. Here we focused on the on the entire Murray-Darling Basin (MDB) of Australia as a case study. The MDB is a large semi-arid region with scarce water resources, high hydroclimatic variability and competing water demands, impacted by climate change, altered flow regimes and land use changes. The basin covers 14% of the Australian continent and contains the nation's largest river system, important groundwater systems, and represents the most important agricultural area in the country. We used Landsat TM and ETM+ data time series to synoptically map the dynamic of surface water extent with an internally consistent algorithm over decades. Within the basin-wide study area we carried out a detailed investigation of the largest river red gum forest in the world, a key site for environmental flow and conservation management. Here we tracked the response of vegetation community condition to flooding across space and time. Results show high interannual variability in number and size of flooded areas. Vegetation community response to flooding varied in space and time and with vegetation types, densities and location relative to areas frequently inundated by environmental water release. Knowledge of the spatial and temporal dynamic of flooding and the response of vegetation communities to flooding is important for management of floodplain wetlands and vegetation communities and for investigating effectiveness of environmental flows and flow regimes in the MDB. Historic flood inundation extent mapped via remote sensing can be used to quantify spatially explicit changes in vegetation communities as outcomes of management scenarios and allow managers to evaluate landscape-scale changes in species distribution in response to water management decisions. This methodology is globally applicable and relevant to areas with competing water demands (e.g., Nile river basin in Northern Africa, Okavango River delta in southwest Africa, Mekong River Basin, Southeast Asia).

  12. Water on titanium dioxide surface: a revisiting by reactive molecular dynamics simulations.

    PubMed

    Huang, Liangliang; Gubbins, Keith E; Li, Licheng; Lu, Xiaohua

    2014-12-16

    The behavior of surface water, especially the adsorption and dissociation characteristics, is a key to understanding and promoting photocatalytic and biomedical applications of titanium dioxide materials. Using molecular dynamics simulations with the ReaxFF force field, we study the interactions between water and five different TiO2 surfaces that are of interest to both experiments and theoretical calculations. The results show that TiO2 surfaces demonstrate different reactivities for water dissociation [rutile (011) > TiO2-B (100) > anatase (001) > rutile (110)], and there is no water dissociation observed on the TiO2-B (001) surface. The simulations also reveal that the water dissociation and the TiO2 surface chemistry change, and the new surface Ti-OH and O-H functional groups affect the orientation of other near-surface water molecules. On the reactive surface, such as the rutile (110) surface, water dissociated and formed new Ti-OH and O-H bonds on the surface. Those functional groups enhanced the hydrogen bond networking with the near-surface water molecules and their configurations. On the nonreactive TiO2-B (001) surface where no molecular or dissociative water adsorption is observed, near-surface water can also form hydrogen bonds with surface oxygen atoms of TiO2, but their distance to the surface is longer than that on the rutile (011) surface. PMID:25423593

  13. A new device for collecting time-integrated water samples from springs and surface water bodies

    USGS Publications Warehouse

    Panno, S.V.; Krapac, I.G.; Keefer, D.A.

    1998-01-01

    A new device termed the 'seepage sampler' was developed to collect representative water samples from springs, streams, and other surface-water bodies. The sampler collects composite, time-integrated water samples over short (hours) or extended (weeks) periods without causing significant changes to the chemical composition of the samples. The water sample within the sampler remains at the ambient temperature of the water body and does not need to be cooled. Seepage samplers are inexpensive to construct and easy to use. A sampling program of numerous springs and/or streams can be designed at a relatively low cost through the use of these samplers. Transient solutes migrating through such flow systems, potentially unnoticed by periodic sampling, may be detected. In addition, the mass loading of solutes (e.g., agrichemicals) may be determined when seepage samplers are used in conjunction with discharge measurements.

  14. Agricultural insecticides threaten surface waters at the global scale

    PubMed Central

    Stehle, Sebastian; Schulz, Ralf

    2015-01-01

    Compared with nutrient levels and habitat degradation, the importance of agricultural pesticides in surface water may have been underestimated due to a lack of comprehensive quantitative analysis. Increasing pesticide contamination results in decreasing regional aquatic biodiversity, i.e., macroinvertebrate family richness is reduced by ?30% at pesticide concentrations equaling the legally accepted regulatory threshold levels (RTLs). This study provides a comprehensive metaanalysis of 838 peer-reviewed studies (>2,500 sites in 73 countries) that evaluates, for the first time to our knowledge on a global scale, the exposure of surface waters to particularly toxic agricultural insecticides. We tested whether measured insecticide concentrations (MICs; i.e., quantified insecticide concentrations) exceed their RTLs and how risks depend on insecticide development over time and stringency of environmental regulation. Our analysis reveals that MICs occur rarely (i.e., an estimated 97.4% of analyses conducted found no MICs) and there is a complete lack of scientific monitoring data for ?90% of global cropland. Most importantly, of the 11,300 MICs, 52.4% (5,915 cases; 68.5% of the sites) exceeded the RTL for either surface water (RTLSW) or sediments. Thus, the biological integrity of global water resources is at a substantial risk. RTLSW exceedances depend on the catchment size, sampling regime, and sampling date; are significantly higher for newer-generation insecticides (i.e., pyrethroids); and are high even in countries with stringent environmental regulations. These results suggest the need for worldwide improvements to current pesticide regulations and agricultural pesticide application practices and for intensified research efforts on the presence and effects of pesticides under real-world conditions. PMID:25870271

  15. Economic Implications of Farmer Storage of Surface Irrigation Water in Federal Projects: El Paso County, Texas 

    E-print Network

    Cornforth, G. C.; Lacewell, R. D.

    1981-01-01

    The Bureau of Reclamation has approved a program for farmer storage of surface irrigation water in Elephant Butte Reservoir, New Mexico. This program would allow individual farmers to store part of their annual surface water allotment...

  16. Biomimicry using Nano-Engineered Enhanced Condensing Surfaces for Sustainable Fresh Water Technology

    E-print Network

    Al-Beaini, Sara

    2012-01-01

    materials-based technology with nano/micro manufacturingNano-Engineered Enhanced Condensing Surfaces for Sustainable Fresh Water TechnologyNano-Engineered Enhanced Condensing Surfaces for Sustainable Fresh Water Technology

  17. atershed water quality concerns in the Northeast have focused on surface water,

    E-print Network

    Scott, Christopher

    and pathogens (particularly Cryptosporidium) in surface water. Given the strong adsorption characteristics the hydrologic transport characteristics of Cryptosporidium are not well understood, there is limited evidence to suggest that Cryptosporidium behaves like a colloidal substance (Brush, 1997); as a result, it is assumed

  18. Models of Fate and Transport of Pollutants in Surface Waters

    NASA Astrophysics Data System (ADS)

    Okome, Gloria Eloho

    There is the need to answer very crucial questions of "what happens to pollutants in surface waters?" This question must be answered to determine the factors controlling fate and transport of chemicals and their evolutionary state in surface waters. Monitoring and experimental methods are used in establishing the environmental states. These measurements are used with the known scientific principles to identify processes and to estimate the future environmental conditions. Conceptual and computational models are needed to analyze environmental processes by applying the knowledge gained from experimentation and theory. Usually, a computational framework includes the mathematics and the physics of the phenomenon, and the measured characteristics to model pollutants interactions and transport in surface water. However, under certain conditions, the complexity of the situation in the actual environment precludes the utilization of these techniques. Pollutants in several forms: Nitrogen (Nitrate, Nitrite, Kjeldhal Nitrogen and Ammonia), Phosphorus (orthophosphate and total phosphorus), bacteria (E-coli and Fecal coliform), Salts (Chloride and Sulfate) are chosen to follow for this research. The objective of this research is to model the fate and transport of these pollutants in non-ideal conditions of surface water measurements and to develop computational methods to forecast their fate and transport. In an environment of extreme drought such as in the Brazos River basin, where small streams flow intermittently, there is added complexity due to the absence of regularly sampled data. The usual modeling techniques are no longer applicable because of sparse measurements in space and time. Still, there is a need to estimate the conditions of the environment from the information that is present. Alternative methods for this estimation must be devised and applied to this situation, which is the task of this dissertation. This research devices a forecasting technique that is based upon sparse data. The method uses the equations of functions that fit the time series data for pollutants at each water quality monitoring stations to interpolate and extrapolate the data and to make estimates of present and future pollution levels. This method was applied to data obtained from the Leon River watershed (Indian creek) and Navasota River.

  19. Global Occurrence and Emission of Rotaviruses to Surface Waters

    PubMed Central

    Kiulia, Nicholas M.; Hofstra, Nynke; Vermeulen, Lucie C.; Obara, Maureen A.; Medema, Gertjan; Rose, Joan B.

    2015-01-01

    Group A rotaviruses (RV) are the major cause of acute gastroenteritis in infants and young children globally. Waterborne transmission of RV and the presence of RV in water sources are of major public health importance. In this paper, we present the Global Waterborne Pathogen model for RV (GloWPa-Rota model) to estimate the global distribution of RV emissions to surface water. To our knowledge, this is the first model to do so. We review the literature to estimate three RV specific variables for the model: incidence, excretion rate and removal during wastewater treatment. We estimate total global RV emissions to be 2 × 1018 viral particles/grid/year, of which 87% is produced by the urban population. Hotspot regions with high RV emissions are urban areas in densely populated parts of the world, such as Bangladesh and Nigeria, while low emissions are found in rural areas in North Russia and the Australian desert. Even for industrialized regions with high population density and without tertiary treatment, such as the UK, substantial emissions are estimated. Modeling exercises like the one presented in this paper provide unique opportunities to further study these emissions to surface water, their sources and scenarios for improved management. PMID:25984911

  20. Global occurrence and emission of rotaviruses to surface waters.

    PubMed

    Kiulia, Nicholas M; Hofstra, Nynke; Vermeulen, Lucie C; Obara, Maureen A; Medema, Gertjan; Rose, Joan B

    2015-01-01

    Group A rotaviruses (RV) are the major cause of acute gastroenteritis in infants and young children globally. Waterborne transmission of RV and the presence of RV in water sources are of major public health importance. In this paper, we present the Global Waterborne Pathogen model for RV (GloWPa-Rota model) to estimate the global distribution of RV emissions to surface water. To our knowledge, this is the first model to do so. We review the literature to estimate three RV specific variables for the model: incidence, excretion rate and removal during wastewater treatment. We estimate total global RV emissions to be 2 × 1018 viral particles/grid/year, of which 87% is produced by the urban population. Hotspot regions with high RV emissions are urban areas in densely populated parts of the world, such as Bangladesh and Nigeria, while low emissions are found in rural areas in North Russia and the Australian desert. Even for industrialized regions with high population density and without tertiary treatment, such as the UK, substantial emissions are estimated. Modeling exercises like the one presented in this paper provide unique opportunities to further study these emissions to surface water, their sources and scenarios for improved management. PMID:25984911

  1. A review of heterogeneous photocatalysis for water and surface disinfection.

    PubMed

    Byrne, John Anthony; Dunlop, Patrick Stuart Morris; Hamilton, Jeremy William John; Fernández-Ibáñez, Pilar; Polo-López, Inmaculada; Sharma, Preetam Kumar; Vennard, Ashlene Sarah Margaret

    2015-01-01

    Photo-excitation of certain semiconductors can lead to the production of reactive oxygen species that can inactivate microorganisms. The mechanisms involved are reviewed, along with two important applications. The first is the use of photocatalysis to enhance the solar disinfection of water. It is estimated that 750 million people do not have accessed to an improved source for drinking and many more rely on sources that are not safe. If one can utilize photocatalysis to enhance the solar disinfection of water and provide an inexpensive, simple method of water disinfection, then it could help reduce the risk of waterborne disease. The second application is the use of photocatalytic coatings to combat healthcare associated infections. Two challenges are considered, i.e., the use of photocatalytic coatings to give "self-disinfecting" surfaces to reduce the risk of transmission of infection via environmental surfaces, and the use of photocatalytic coatings for the decontamination and disinfection of medical devices. In the final section, the development of novel photocatalytic materials for use in disinfection applications is reviewed, taking account of materials, developed for other photocatalytic applications, but which may be transferable for disinfection purposes. PMID:25830789

  2. Novel Americium Treatment Process for Surface Water and Dust Suppression Water

    SciTech Connect

    Tiepel, E.W.; Pigeon, P. [Golder Associates (United States); Nesta, S. [Kaiser-Hill Company, LLC (United States); Anderson, J. [Rocky Flats Closure Site Services - RFCSS (United States)

    2006-07-01

    The Rocky Flats Environmental Technology Site (RFETS), a former nuclear weapons production plant, has been remediated under CERCLA and decommissioned to become a National Wildlife Refuge. The site conducted this cleanup effort under the Rocky Flats Cleanup Agreement (RFCA) that established limits for the discharge of surface and process waters from the site. At the end of 2004, while a number of process buildings were undergoing decommissioning, routine monitoring of a discharge pond (Pond A-4) containing approximately 28 million gallons of water was discovered to have been contaminated with a trace amount of Americium-241 (Am-241). While the amount of Am-241 in the pond waters was very low (0.5 - 0.7 pCi/l), it was above the established Colorado stream standard of 0.15 pCi/l for release to off site drainage waters. The rapid successful treatment of these waters to the regulatory limit was important to the site for two reasons. The first was that the pond was approaching its hold-up limit. Without rapid treatment and release of the Pond A-4 water, typical spring run-off would require water management actions to other drainages onsite or a mass shuttling of water for disposal. The second reason was that this type of contaminated water had not been treated to the stringent stream standard at Rocky Flats before. Technical challenges in treatment could translate to impacts on water and secondary waste management, and ultimately, cost impacts. All of the technical challenges and specific site criteria led to the conclusion that a different approach to the treatment of this problem was necessary and a crash treatability program to identify applicable treatment techniques was undertaken. The goal of this program was to develop treatment options that could be implemented very quickly and would result in the generation of no high volume secondary waste that would be costly to dispose. A novel chemical treatment system was developed and implemented at the RFETS to treat Am-241 contaminated pond water, surface run-off and D and D dust suppression water during the later stages of the D and D effort at Rocky Flats. This novel chemical treatment system allowed for highly efficient, high-volume treatment of all contaminated waste waters to the very low stream standard of 0.15 pCi/1 with strict compliance to the RFCA discharge criteria for release to off-site surface waters. The rapid development and implementation of the treatment system avoided water management issues that would have had to be addressed if contaminated water had remained in Pond A-4 into the Spring of 2005. Implementation of this treatment system for the Pond A-4 waters and the D and D waters from Buildings 776 and 371 enabled the site to achieve cost-effective treatment that minimized secondary waste generation, avoiding the need for expensive off-site water disposal. Water treatment was conducted for a cost of less than $0.20/gal which included all development costs, capital costs and operational costs. This innovative and rapid response effort saved the RFETS cleanup program well in excess of $30 million for the potential cost of off-site transportation and treatment of radioactive liquid waste. (authors)

  3. The Effect of Contact Angle on the Depletion Layer when Water Meets a Hydrophobic Surface

    NASA Astrophysics Data System (ADS)

    Poynor, Adele

    2013-03-01

    By definition hydrophobic substances hate water. Water placed on a hydrophobic surface will form a drop in order to minimize its contact area. What happens when water is forced into contact with a hydrophobic surface? One theory is that an ultra-thin low-density depletion layer forms near the surface. We investigate the effect of contact angle on depletion layer formation using the surface sensitive technique of Surface Plasmon Resonance.

  4. 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.

  5. Effect of composition on adsorption of water on perfect olivine surfaces

    E-print Network

    Deymier, Pierre

    Effect of composition on adsorption of water on perfect olivine surfaces M. STIMPFL 1 , M.J. DRAKE's water. We are investigating if adsorption of water onto mineral surfaces in the accretion disk could with radii gas and dust with high surface area, points

  6. EFFECT OF SEDIMENT ON THE FATE OF METOLACHLOR AND ATRAZINE IN SURFACE WATER

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Experiments were conducted to determine the persistence of atrazine and metolachlor in surface water, and to evaluate the contribution of sediment to their dissipation from surface waters. Atrazine was more persistent than metolachlor in the sediment-free surface water systems. First-order 50% dissi...

  7. SURFACE WATER VAPOR EXCHANGES ON THE GREENLAND ICE SHEET DERIVED FROM AUTOMATED WEATHER STATION DATA

    E-print Network

    Box, Jason E.

    1 SURFACE WATER VAPOR EXCHANGES ON THE GREENLAND ICE SHEET DERIVED FROM AUTOMATED WEATHER STATION.D. Geography) Surface Water Vapor Exchanges on the Greenland Ice Sheet Derived From Automated Weather Station observations are used to estimate surface water vapor exchanges at Greenland ice sheet sites and for the ice

  8. Ground-water/surface-water relations along Honey Creek, Washtenaw County, Michigan, 2003

    USGS Publications Warehouse

    Healy, Denis F.

    2005-01-01

    The U.S. Geological Survey (USGS), in cooperation with the city of Ann Arbor, Mich., investigated the ground-water/surface-water relations along the lower reaches of Honey Creek, Washtenaw County, Mich., and an unnamed tributary to Honey Creek (the discharge tributary) from June through October 2003. Streamflow in these reaches was artificially high during a naturally low-flow period due to an anthropogenic discharge. Ground-water/surface-water relations were examined by seepage runs (series of streamflow measurements for the computation of streams gains or losses) and measurements of the difference in head between the stream surface and shallow aquifer. Specific conductance and water-temperature measurements were used as ancillary data to help identify gaining and losing reaches. Three seepage runs and four runs in which hydraulic-head differences between the stream and shallow aquifer were measured (piezometer runs) were made during periods of base flow. Streamflow measurements were made at 18 sites for the seepage runs. Instream piezometers were installed at 16 sites and bank piezometers were installed at 2 sites. Two deeper instream piezometers were installed at site 13 on September 4, 2003 to collect additional data on the ground-water/surface-water relations at that site. The seepage runs indicate that the main stem of Honey Creek and the discharge tributary in the study area are overall gaining reaches. The seepage runs also indicate that smaller reaches of Honey Creek and the discharge tributary may be losing reaches and that this relation may change over time with changing hydraulic conditions. The piezometer-run measurements support the seepage-run results on the main stem, whereas piezometer-run measurements both support and conflict with seepage-run measurements on the discharge tributary. Seepage runs give an average for the reach, whereas piezometer head-difference measurements are for a specific area around the piezometer. Data that may appear to be conflicting actually may be showing that within a gaining reach there are localized areas that lose streamflow The overall gain in streamflow along with specific measurements of head differences, specific conductance, and water temperature indicate that ground water is discharging to Honey Creek and the discharge tributary. Although reaches and areas that lose streamflow have been identified, data collected during this study cannot confirm or disprove that the loss is to the regional ground-water system.

  9. Water resources data for Florida, water year 1992. Volume 3A. Southwest Florida surface water. Water-data report (Annual), 1 October 1991-30 September 1992

    SciTech Connect

    Coffin, J.E.; Fletcher, W.L.

    1993-04-01

    Water resources data for the 1992 water year in Florida consist of continuous or daily discharge for 327 streams, periodic discharge for 20 streams, miscellaneous discharge for 65 streams, continuous or daily stage for 137 streams, continuous daily tide stage for 5 sites, periodic stage for 23 streams, peak discharge for 21 streams, and peak stage for 29 streams; continuous or daily elevations for 63 lakes, periodic elevations for 64 lakes; continuous ground-water levels for 430 wells, periodic ground-water levels for 1,074 wells and miscellaneous water level measurements for 1,501 wells; quality-of-water data for 140 surface-water sites and 683 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 71 streams, miscellaneous discharge for 12 streams, continuous daily stage for 19 streams, peak discharge for 13 streams, continuous elevations for 15 lakes, periodic elevations for 16 lakes, and quality-of-water for 61 surface-water sites.

  10. Evaluation of surface water resources from machine-processing of ERTS multispectral data

    NASA Technical Reports Server (NTRS)

    Mausel, P. W.; Todd, W. J.; Baumgardner, M. F.; Mitchell, R. A.; Cook, J. P.

    1976-01-01

    The surface water resources of a large metropolitan area, Marion County (Indianapolis), Indiana, are studied in order to assess the potential value of ERTS spectral analysis to water resources problems. The results of the research indicate that all surface water bodies over 0.5 ha were identified accurately from ERTS multispectral analysis. Five distinct classes of water were identified and correlated with parameters which included: degree of water siltiness; depth of water; presence of macro and micro biotic forms in the water; and presence of various chemical concentrations in the water. The machine processing of ERTS spectral data used alone or in conjunction with conventional sources of hydrological information can lead to the monitoring of area of surface water bodies; estimated volume of selected surface water bodies; differences in degree of silt and clay suspended in water and degree of water eutrophication related to chemical concentrations.

  11. Keywordscondensation tube, surface modification, waste heat and condensation water recovery system

    E-print Network

    Leu, Tzong-Shyng "Jeremy"

    Keywordscondensation tube, surface modification, waste heat and condensation water recovery merge to form water thin film on tube condenser surface. The condensing mechanism will change from high techniques is waste heat and condensation water recovery system. Waste heat and condensation water recovery

  12. Metagenomes of microbial communities in arsenic- and pathogen-contaminated well and surface water from bangladesh.

    PubMed

    Layton, Alice C; Chauhan, Archana; Williams, Daniel E; Mailloux, Brian; Knappett, Peter S K; Ferguson, Andrew S; McKay, Larry D; Alam, M Jahangir; Matin Ahmed, Kazi; van Geen, Alexander; Sayler, Gary S

    2014-01-01

    The contamination of drinking water from both arsenic and microbial pathogens occurs in Bangladesh. A general metagenomic survey of well water and surface water provided information on the types of pathogens present and may help elucidate arsenic metabolic pathways and potential assay targets for monitoring surface-to-ground water pathogen transport. PMID:25414497

  13. Quality of surface-water supplies in the Triangle area of North Carolina, water year 2009

    USGS Publications Warehouse

    Pfeifle, C. A.; Giorgino, M. J.; Rasmussen, R. B.

    2014-01-01

    Surface-water supplies are important sources of drinking water for residents in the Triangle area of North Carolina, which is located within the upper Cape Fear and Neuse River Basins. Since 1988, the U.S. Geological Survey and a consortium of governments have tracked water-quality conditions and trends in several of the area’s water-supply lakes and streams. This report summarizes data collected through this cooperative effort, known as the Triangle Area Water Supply Monitoring Project, during October 2008 through September 2009. Major findings for this period include: - Annual precipitation was approximately 20 percent below the long-term mean (average) annual precipitation. - Streamflow was below the long-term mean at the 10 project streamgages during most of the year. - More than 7,000 individual measurements of water quality were made at a total of 26 sites—15 in the Neuse River Basin and 11 in the Cape Fear River Basin. Forty-seven water-quality properties and constituents were measured. - All observations met North Carolina water-quality standards for water temperature, pH, hardness, chloride, fluoride, sulfate, nitrate, arsenic, cadmium, chromium, lead, nickel, and selenium. - North Carolina water-quality standards were exceeded one or more times for dissolved oxygen, dissolved oxygen percent saturation, chlorophyll a, mercury, copper, iron, manganese, silver, and zinc. Exceedances occurred at 23 sites—13 in the Neuse River Basin and 10 in the Cape Fear River Basin. - Stream samples collected during storm events contained elevated concentrations of 18 water-quality constituents compared to samples collected during non-storm events. - Concentrations of nitrogen and phosphorus were within ranges observed during previous years. - Five reservoirs had chlorophyll a concentrations in excess of 40 micrograms per liter at least once during 2009: Little River Reservoir, Falls Lake, Cane Creek Reservoir, University Lake, and Jordan Lake.

  14. Microbial community genomics in eastern Mediterranean Sea surface waters.

    PubMed

    Feingersch, Roi; Suzuki, Marcelino T; Shmoish, Michael; Sharon, Itai; Sabehi, Gazalah; Partensky, Frédéric; Béjà, Oded

    2010-01-01

    Offshore waters of the eastern Mediterranean Sea are one of the most oligotrophic regions on Earth in which the primary productivity is phosphorus limited. To study the unexplored function and physiology of microbes inhabiting this system, we have analyzed a genomic library from the eastern Mediterranean Sea surface waters by sequencing both termini of nearly 5000 clones. Genome recruitment strategies showed that the majority of high-scoring pairs corresponded to genomes from the Alphaproteobacteria (SAR11-like and Rhodobacterales), Cyanobacteria (Synechococcus and high-light adapted Prochlorococcus) and diverse uncultured Gammaproteobacteria. The community structure observed, as evaluated by both protein similarity scores or metabolic potential, was similar to that found in the euphotic zone of the ALOHA station off Hawaii but very different from that of deep aphotic zones in both the Mediterranean Sea and the Pacific Ocean. In addition, a strong enrichment toward phosphate and phosphonate uptake and utilization metabolism was also observed. PMID:19693100

  15. Modeling global distribution of agricultural insecticides in surface waters.

    PubMed

    Ippolito, Alessio; Kattwinkel, Mira; Rasmussen, Jes J; Schäfer, Ralf B; Fornaroli, Riccardo; Liess, Matthias

    2015-03-01

    Agricultural insecticides constitute a major driver of animal biodiversity loss in freshwater ecosystems. However, the global extent of their effects and the spatial extent of exposure remain largely unknown. We applied a spatially explicit model to estimate the potential for agricultural insecticide runoff into streams. Water bodies within 40% of the global land surface were at risk of insecticide runoff. We separated the influence of natural factors and variables under human control determining insecticide runoff. In the northern hemisphere, insecticide runoff presented a latitudinal gradient mainly driven by insecticide application rate; in the southern hemisphere, a combination of daily rainfall intensity, terrain slope, agricultural intensity and insecticide application rate determined the process. The model predicted the upper limit of observed insecticide exposure measured in water bodies (n = 82) in five different countries reasonably well. The study provides a global map of hotspots for insecticide contamination guiding future freshwater management and conservation efforts. PMID:25555206

  16. Methane in surface waters of Oregon estuaries and rivers

    SciTech Connect

    de Angelis, M.A.; Lilley, M.D. (Washington Univ., Seattle (USA))

    1987-05-01

    Methane concentrations in surface waters of Oregon rivers and estuaries were measured over a four-year period. Geographic variations in riverine CH{sub 4} were observed. Results from undisturbed forest streams indicate that rivers can contain high natural levels of CH{sub 4} not attributable to pollution. Lateral diffusion and runoff from saturated forest and fertilized agricultural soils may be important in determining methane levels in rivers. Methane concentrations in well-flushed estuaries appear to be controlled mainly by mixing between high CH{sub 4}-containing river water and low CH{sub 4}-containing seawater endmembers. Rivers and estuaries were found to be sources of methane to the atmosphere. Calculated daily fluxes to the atmosphere ranged from 1.2 to 71 mg CH{sub 4} sq m for rivers and from 0.04 to 21 mg CH{sub 4} sq m for estuarine samples. 24 refs., 4 figs., 3 tabs.

  17. Toxicity testing of ground water, surface water and waste water in the island of Cyprus

    SciTech Connect

    McNaughton, E. [Environmental Protection Agency, San Francisco, CA (United States); Kouris, D. [Agricultural Research Inst., Nicosia (Cyprus); Guden, H. [Department of the Environment, Lefkosa (Cyprus); Gokcekus, H. [Near East Univ., Lefkosa (Cyprus)

    1995-12-31

    The island of Cyprus is an exporter of agricultural products to the European Community (EC). Public health and environmental toxicity testing programs on the island, especially in the Greek-dominated south, are based on EC models. Following EC guidelines, an environmental toxicology laboratory is being established at the State Laboratory in Nicosia. It will test water for toxicity using the acute Daphnia magna survival test, the chronic 4-day algal growth test (Selenastrum capricomutum), Microtox and Mutatox. During a 6-month survey of water and wastewater using the acute Ceriodaphnia dubia test and the algal growth test, the question of the relevance of environmental toxicity testing in an ecosystem devoid of natural year round freshwater sources, excepting ground water, was examined. Municipal wells, potable and agricultural water reservoirs, municipal and industrial effluent were tested. Preliminary studies showed some municipal well water to be toxic to freshwater species, probably due to high salt content. Water from a newly developed reservoir was toxic, probably due to its location at the base of eroding hills recently mined for copper. Effluent from a paper factory was toxic, but the reservoir into which it flows was not, nor was the sulfide-rich water toxic to untreated seeds. For the water-deficient ecosystem of Cyprus, the environmental testing program must be different from those developed for the European continent. The choice of appropriate test species, the need to focus on water quality for public health and agricultural use, and the possible benefits of nutrient-enriched waste water flowing into sterile ocean water, must all be considered.

  18. The effect of water temperature and synoptic winds on the development of surface flows over narrow, elongated water bodies

    NASA Technical Reports Server (NTRS)

    Segal, M.; Pielke, R. A.

    1985-01-01

    Simulations of the thermally induced breeze involved with a relatively narrow, elongated water body is presented in conjunction with evaluations of sensible heat fluxes in a stable marine atmospheric surface layer. The effect of the water surface temperature and of the large-scale synoptic winds on the development of surface flows over the water is examined. As implied by the sensible heat flux patterns, the simulation results reveal the following trends: (1) when the synoptic flow is absent or light, the induced surface breeze is not affected noticeably by a reduction of the water surface temperature; and (2) for stronger synoptic flow, the resultant surface flow may be significantly affected by the water surface temperature.

  19. Microbial Monitoring of Surface Water in South Africa: An Overview

    PubMed Central

    Luyt, Catherine D.; Tandlich, Roman; Muller, Wilhelmine J.; Wilhelmi, Brendan S.

    2012-01-01

    Infrastructural problems force South African households to supplement their drinking water consumption from water resources of inadequate microbial quality. Microbial water quality monitoring is currently based on the Colilert®18 system which leads to rapidly available results. Using Escherichia coli as the indicator microorganism limits the influence of environmental sources on the reported results. The current system allows for understanding of long-term trends of microbial surface water quality and the related public health risks. However, rates of false positive for the Colilert®18-derived concentrations have been reported to range from 7.4% to 36.4%. At the same time, rates of false negative results vary from 3.5% to 12.5%; and the Colilert medium has been reported to provide for cultivation of only 56.8% of relevant strains. Identification of unknown sources of faecal contamination is not currently feasible. Based on literature review, calibration of the antibiotic-resistance spectra of Escherichia coli or the bifidobacterial tracking ratio should be investigated locally for potential implementation into the existing monitoring system. The current system could be too costly to implement in certain areas of South Africa where the modified H2S strip test might be used as a surrogate for the Colilert®18. PMID:23066390

  20. Water electrolysis using electrodes with modified surface/volume

    NASA Astrophysics Data System (ADS)

    Vanags, M.; Kleperis, J.; Bajars, G.; Lusis, A.

    2007-12-01

    Steel (12X18H10T) as the real electrode material is investigated to be used for different electrolysis applications, as the parallel plate electrodes for standard electrolysis in alkaline solutions, as well as the coaxial electrodes for high voltage short pulse electrolysis in water. The increase of catalytic activity of steel electrodes for the hydrogen evolution reaction (HER) in different electrolytes could be easy achieved by co-deposition of metal hydride (LaNi5) particles with electrolytic nickel. The results revealed that Ni + LaNi5 with high real surface have a very high activity for the HER, due to the high active surface and specific microstructural features determining the electrocatalytic activity of the investigated alloys.

  1. How a Change in Water Phase Affects Surface Temperatures

    NSDL National Science Digital Library

    2012-08-03

    In this problem-based learning (PBL) activity, students take on the role of a student research scientist and explore the role of solar energy in determining climate. Students conduct experiments to observe how a change in water phase affects surface temperatures. Materials required for the investigation include 2 aquariums, dry sand or soil, two heat lamps, and two thermometers.The lesson is supported by teacher notes, answer key, glossary and an appendix with information about using PBL in the classroom. This is the second of three activities in Investigating the Climate System: Energy, a Balancing Act.

  2. Traveling surface waves of moderate amplitude in shallow water

    PubMed Central

    Gasull, Armengol; Geyer, Anna

    2014-01-01

    We study traveling wave solutions of an equation for surface waves of moderate amplitude arising as a shallow water approximation of the Euler equations for inviscid, incompressible and homogeneous fluids. We obtain solitary waves of elevation and depression, including a family of solitary waves with compact support, where the amplitude may increase or decrease with respect to the wave speed. Our approach is based on techniques from dynamical systems and relies on a reformulation of the evolution equation as an autonomous Hamiltonian system which facilitates an explicit expression for bounded orbits in the phase plane to establish existence of the corresponding periodic and solitary traveling wave solutions. PMID:24895474

  3. Numerical modeling of runback water on ice protected aircraft surfaces

    NASA Technical Reports Server (NTRS)

    Al-Khalil, Kamel M.; Keith, Theo G., Jr.; Dewitt, Kenneth J.

    1992-01-01

    A numerical simulation for 'running wet' aircraft anti-icing systems is developed. The model includes breakup of the water film, which exists in regions of direct impingement, into individual rivulets. The wetness factor distribution resulting from the film breakup and the rivulet configuration on the surface are predicted in the numerical solution procedure. The solid wall is modeled as a multilayer structure and the anti-icing system used is of the thermal type utilizing hot air and/or electrical heating elements embedded with the layers. Details of the calculation procedure and the methods used are presented.

  4. Numerical modeling of runback water on ice protected aircraft surfaces

    NASA Astrophysics Data System (ADS)

    Al-Khalil, Kamel M.; Keith, Theo G., Jr.; Dewitt, Kenneth J.

    A numerical simulation for 'running wet' aircraft anti-icing systems is developed. The model includes breakup of the water film, which exists in regions of direct impingement, into individual rivulets. The wetness factor distribution resulting from the film breakup and the rivulet configuration on the surface are predicted in the numerical solution procedure. The solid wall is modeled as a multilayer structure and the anti-icing system used is of the thermal type utilizing hot air and/or electrical heating elements embedded with the layers. Details of the calculation procedure and the methods used are presented.

  5. Diversity of Salmonella Isolates from Central Florida Surface Waters

    PubMed Central

    McEgan, Rachel; Chandler, Jeffrey C.; Goodridge, Lawrence D.

    2014-01-01

    Identification of Salmonella serotypes is important for understanding the environmental diversity of the genus Salmonella. This study evaluates the diversity of Salmonella isolates recovered from 165 of 202 Central Florida surface water samples and investigates whether the serotype of the environmental Salmonella isolates can be predicted by a previously published multiplex PCR assay (S. Kim, J. G. Frye, J. Hu, P. J. Fedorka-Cray, R. Gautom, and D. S. Boyle, J. Clin. Microbiol. 44:3608–3615, 2006, http://dx.doi.org/10.1128/JCM.00701-06). Multiplex PCR was performed on 562 Salmonella isolates (as many as 36 isolates per water sample) to predict serotypes. Kauffmann-White serogrouping was used to confirm multiplex PCR pattern groupings before isolates were serotyped, analyzed by pulsed-field gel electrophoresis, and assayed for antimicrobial susceptibility. In 41.2% of the Salmonella-positive water samples, all Salmonella isolates had identical multiplex PCR patterns; in the remaining 58.8%, two or more multiplex PCR patterns were identified. Within each sample, isolates with matching multiplex PCR patterns had matching serogroups. The multiplex patterns of 495 isolates (88.1%) did not match any previously reported pattern. The remaining 68 isolates matched reported patterns but did not match the serotypes for those patterns. The use of the multiplex PCR allowed the number of isolates requiring further analysis to be reduced to 223. Thirty-three Salmonella enterica serotypes were identified; the most frequent included serotypes Muenchen, Rubislaw, Anatum, Gaminara, and IV_50:z4,z23:?. A majority (141/223) of Salmonella isolates clustered into one genotypic group. Salmonella isolates in Central Florida surface waters are serotypically, genotypically, and phenotypically (in terms of antimicrobial susceptibility) diverse. While isolates could be grouped as different or potentially the same using multiplex PCR, the multiplex PCR pattern did not predict the Salmonella serotype. PMID:25172861

  6. Sea Surface Salinity Understanding the Interactions Between the Global Water Cycle, Ocean Circulation and Climate

    E-print Network

    Waliser, Duane E.

    Sea Surface Salinity Understanding the Interactions Between the Global Water Cycle, Ocean Circulation and Climate Aquarius will provide unprecedented global maps of surface sea water salinity?" Sea surface salinity is the primary surface tracer of freshwater input and output to the ocean

  7. Polyelectrolytes Ability in Reducing Atrazine Concentration in Water: Surface Effects

    PubMed Central

    Heijman, S. G. J.; Lopes, S. I. C.; Rietveld, L. C.

    2014-01-01

    This paper reports on the direct ability of two positively charged organic polyelectrolytes (natural-based and synthetic) to reduce the atrazine concentration in water. The adsorption study was set up using multiple glass vessels with different polymer dosing levels followed by ultrafiltration with a 1?kDa membrane. The addition of polymers exhibited a capability in reducing the atrazine concentration up to a maximum of 60% in surface-to-volume ratio experiments. In the beginning, the theoretical L-type of the isotherm of Giles' classification was expected with an increase in the dosage of the polymer. However, in this study, the conventional type of isotherm was not observed. It was found that the adsorption of the cationic polymer on the negatively charged glass surface was necessary and influential for the removal of atrazine. Surface-to-volume ratio adsorption experiments were performed to elucidate the mechanisms and the polymer configuration. The glass surface area was determined to be a limiting parameter in the adsorption mechanism. PMID:25197693

  8. Pest Control: Caffeine as a repellent for slugs and snails

    Microsoft Academic Search

    Robert G. Hollingsworth; John W. Armstrong; Earl Campbell

    2002-01-01

    Most commercial products for snail and slug control contain either metaldehyde or methiocarb as the active ingredient, the residues of which are not permitted in food crops in the United States. We have discovered that solutions of caffeine are effective in killing or repelling slugs and snails when applied to foliage or the growing medium of plants. Because caffeine is

  9. Carthusian snail Monacha cartusiana Michigan State University's invasive species factsheets

    E-print Network

    Carthusian snail Monacha cartusiana Michigan State University's invasive species factsheets as a prohibited mollusk species by Michigan's plant protection regulations (MDA 2009). Plant hosts A wide variety plants. In addition, invasive snails can potentially transmit plant and animal pathogens and displace

  10. Snails as Biomonitors of Oil-Spill and Bioremediation Strategies

    Microsoft Academic Search

    L. E. J. Lee; J. Stassen; A. McDonald; C. Culshaw; A. D. Venosa; K. Lee

    2002-01-01

    Aquatic and pulmonate snails were evaluated for their suitability as biomonitors of habitat recovery following an experimental oil spill in a freshwater marshland. The mystery snail, Viviparus georgianus, and the mimic pondsnail, Pseudosuccinea columella, were used as sediment quality biomonitors for a controlled oil-spill experiment at a wetland site along the St. Lawrence River (Ste. Croix, Quebec) to assess the

  11. RISK-BASED PROCEDURES USED TO SUPPORT REMEDIATION OF A GROUND WATER- SURFACE WATER TRANSITION ZONE CONTAMINATED WITH CHLOROBENZENES

    EPA Science Inventory

    Risk-Based Procedures Used to Support Remediation of a Ground Water - Surface Water Transition Zone Contaminated with Chlorobenzenes (Eastland Woolen Mill Superfund Site, Corinna, ME) In-situ and laboratory toxicity, sediment-toxicity identification evaluation (SIE), benthic macr...

  12. The control of snail hosts of bilharziasis and fascioliasis in Southern Rhodesia

    PubMed Central

    Clarke, V. DE V.; Shiff, C. J.; Blair, D. M.

    1961-01-01

    The authors review the experimental work that has been done since the Second World War on the use of chemical molluscicides in Southern Rhodesia and describe the development of a co-operative snail control campaign involving local landowners and various Government departments. In 1959 and 1960 efforts were concentrated on four large-scale experiments to test the methods of application of copper sulfate, sodium pentachlorophenate and Bayer 73 under a variety of climatic and physiographic conditions. From this work the authors conclude that it would appear possible and practicable to control vector snails in natural water courses and reservoirs in savannah areas of Central Africa to a degree at which it is thought that transmission of bilharziasis from man to man and of fascioliasis from animal to animal does not take place. PMID:13879773

  13. Groundwater- Surface Water Interaction at the Regional Scale

    NASA Astrophysics Data System (ADS)

    Barthel, Roland; Banzhaf, Stefan

    2014-05-01

    Today, both scientists and practitioners agree that management of water resources has to be performed in an integrated way. At the same time there is an increasing need for research at the regional scale (here 103 to 106 km2), because (i) this is the scale where interaction between environmental and human systems is fully developed through various links between supply and consumption, sources and sinks, etc. and (ii) the regional scale links global change to local impacts and action. The regional scale is the scale of management - to acknowledge this might be an important first step in finding the appropriate ways to address it. In any case, it is of utmost importance, that groundwater-surface water (GW-SW) interaction - as a central process of the hydrological cycle - is considered on the regional scale too. The starting point for the present contribution is two regional integrated models developed by the first author and the problems encountered in the attempt to implement adequately the GW-SW interaction therein. To evaluate if solutions to these problems were available from other studies, the available knowledge and tools were reviewed to extract common findings and guidance on how to analyse, describe and finally model GW-SW on the regional scale. Here we compare the characteristics of GW-SW interaction at different scales, the particularities of the regional scale, the available knowledge on how to regionalize and/or upscale processes, properties and parameters from smaller to larger scales and the model concepts available to describe GW-SW interaction at the regional scale. The overall conclusions are somewhat disillusioning: A large variety of research efforts has addressed the underlying problem setting and a plethora of tools were developed, yet GW-SW interaction at the regional scale is rarely explicitly addressed in a systematic way. It is evident that regional scale hydrological research on coupled surface-subsurface systems has to deal with high complexity paired with low data availability and heterogeneity of data. At the same time, GW-SW interaction at the regional scale can no longer be considered a process focused on the interface between groundwater and surface water body - processes in between and far away from river stretches increasingly outweigh local processes. To account for this, models that simultaneously describe all the related processes in groundwater, surface water and the unsaturated zone are required. Fully coupled physics-based models (for example HydroGeoSphere or ParFlow) seem to be the most appropriate for this work. However, the data availability and heterogeneity issues form an obstacle to employing such complex models at the regional scale. A way out of the dilemma might be fully coupled physics-based models that are flexible enough to allow (harsh) simplification where necessary and nested approaches. However, models that satisfy the performance criteria usually applied within the scientific community might never be feasible at regional scales. Regional scale integrated models of groundwater-surface water systems might thus have to be developed from a different perspective: Either merely driven by unique, context- and scale-specific demands of practical water resources management or by developing integrated regional models for the sole purpose to provide a regional framework for nested local solutions. The ongoing discussion of the complexity-versus-simplicity-question in hydrological modelling might not be helpful in the attempt to find the appropriate path to successful regional scale integrated modelling - if it is just led within the hydrologic modelling community alone. Participatory and transdisciplinary approaches might be more helpful in the attempt to provide meaningful regional solutions.

  14. Groundwater-surface water interactions in fractured Mediterranean mountain environments

    NASA Astrophysics Data System (ADS)

    Eliades, Marinos; Bruggeman, Adriana; Lange, Manfred A.

    2014-05-01

    Groundwater and surface-water systems interact in a variety of geological, morphological, and climatic settings. Vegetation also plays a key role in these interactions as it transfers water from the subsurface and groundwater table towards the surface, where it is redistributed by plants and trees in different soil depths. Cyprus is at the drier end of the precipitation spectrum of the Mediterranean region and has intense seasonal variations in precipitation with frequent droughts. In order to confront water scarcity issues and improve water management plans in the future, we need to obtain a better understanding of the groundwater and surface-water interactions and quantify the hydrological processes in this complex fractured Mediterranean mountain environment. The upstream and midstream of Peristerona watershed was selected as the study area (77 km2). It is a forested mountain watershed with steep slopes (mean 22o) and elevation varying from 417 to 1543 m. The main formations in the area are lower and upper pillow lavas, basalt, diabase and gabbro. From a hydrogeological point of view the upstream area consists mainly of heavily fractured intrusive formations that can hold groundwater inside the fractured zones and in some areas it consists of plutonic rocks with springs. The midstream area is dominated by volcanics with submarine pillow lavas. To assess the surface and groundwater interactions a nested watershed approach will be followed with the synthesis and collation of hydrometric data through a dense monitoring network. Continuous measurements of rainfall, runoff and groundwater levels will be taken. Watershed characteristics will be processed in GIS environment. Also measurements of environmental stable isotopes (O18and H2) will be taken. In addition sap flow instruments will be installed in Pinus brutia species among with soil moisture sensors. Results will quantify the water uptake by trees (Pinus Brutia sp.) and the hydraulic redistribution back to the different soil depths. It will enable an assessment of the contribution of trees to the natural water cycle in situations similar to this environment. Hydrometric analysis for each nested watershed will be applied and results are expected to show threshold values of rainfall for runoff generation and the contribution of groundwater (baseflow) to the river flow and vice versa. Relations between geology, morphology and climate will also be revealed. Rainfall and runoff data are currently available from two stations, Panagia bridge (438 m) and Platanistasa (780 m). Results show a linear relation between the daily runoff of the two stations. The relatively higher runoff in Platanistasa, as compared to Panagia bridge, is probably due to the steep slopes and the higher rainfall rates. Baseflow occurring at the end of the rain season indicate that the fractures in the geologic formations fill up during the rainy season and discharge during the end of the season. During the summer period, even when rainfall events occur, there is very little or no runoff generation.

  15. The Mitochondrial Genome of the Venomous Cone Snail Conus consors

    PubMed Central

    Brauer, Age; Kurz, Alexander; Stockwell, Tim; Baden-Tillson, Holly; Heidler, Juliana; Wittig, Ilka; Kauferstein, Silke; Mebs, Dietrich; Stöcklin, Reto; Remm, Maido

    2012-01-01

    Cone snails are venomous predatory marine neogastropods that belong to the species-rich superfamily of the Conoidea. So far, the mitochondrial genomes of two cone snail species (Conus textile and Conus borgesi) have been described, and these feed on snails and worms, respectively. Here, we report the mitochondrial genome sequence of the fish-hunting cone snail Conus consors and describe a novel putative control region (CR) which seems to be absent in the mitochondrial DNA (mtDNA) of other cone snail species. This possible CR spans about 700 base pairs (bp) and is located between the genes encoding the transfer RNA for phenylalanine (tRNA-Phe, trnF) and cytochrome c oxidase subunit III (cox3). The novel putative CR contains several sequence motifs that suggest a role in mitochondrial replication and transcription. PMID:23236512

  16. Transport and fate of nitrate at the ground-water/surface-water interface

    USGS Publications Warehouse

    Puckett, L.J.; Zamora, C.; Essaid, H.; Wilson, J.T.; Johnson, H.M.; Brayton, M.J.; Vogel, J.R.

    2008-01-01

    Although numerous studies of hyporheic exchange and denitrification have been conducted in pristine, high-gradient streams, few studies of this type have been conducted in nutrient-rich, low-gradient streams. This is a particularly important subject given the interest in nitrogen (N) inputs to the Gulf of Mexico and other eutrophic aquatic systems. A combination of hydrologic, mineralogical, chemical, dissolved gas, and isotopic data, were used to determine the processes controlling transport and fate of NO3- in streambeds at five sites across the USA. Water samples were collected from streambeds at depths ranging from 0.3 to 3 m at three to five points across the stream and in two to five separate transects. Residence times of water ranging from 0.28 to 34.7 d m-1 in the streambeds of N-rich watersheds played an important role in allowing denitrification to decrease NO3- concentrations. Where potential electron donors were limited and residence times were short, denitrification was limited. Consequently, in spite of reducing conditions at some sites, NO3- was transported into the stream. At two of the five study sites, NO3- in surface water infiltrated the streambeds and concentrations decreased, supporting current models that NO3- would be retained in N-rich streams. At the other three study sites, hydrogeologic controls limited or prevented infiltration of surface water into the streambed, and ground-water discharge contributed to NO 3- loads. Our results also show that in these low hydrologic-gradient systems, storm and other high-flow events can be important factors for increasing surface-water movement into streambeds. Copyright ?? 2008 by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America. All rights reserved.

  17. Transport and fate of nitrate at the ground-water/surface-water interface.

    PubMed

    Puckett, Larry J; Zamora, Celia; Essaid, Hedeff; Wilson, John T; Johnson, Henry M; Brayton, Michael J; Vogel, Jason R

    2008-01-01

    Although numerous studies of hyporheic exchange and denitrification have been conducted in pristine, high-gradient streams, few studies of this type have been conducted in nutrient-rich, low-gradient streams. This is a particularly important subject given the interest in nitrogen (N) inputs to the Gulf of Mexico and other eutrophic aquatic systems. A combination of hydrologic, mineralogical, chemical, dissolved gas, and isotopic data were used to determine the processes controlling transport and fate of NO(3)(-) in streambeds at five sites across the USA. Water samples were collected from streambeds at depths ranging from 0.3 to 3 m at three to five points across the stream and in two to five separate transects. Residence times of water ranging from 0.28 to 34.7 d m(-1) in the streambeds of N-rich watersheds played an important role in allowing denitrification to decrease NO(3)(-) concentrations. Where potential electron donors were limited and residence times were short, denitrification was limited. Consequently, in spite of reducing conditions at some sites, NO(3)(-) was transported into the stream. At two of the five study sites, NO(3)(-) in surface water infiltrated the streambeds and concentrations decreased, supporting current models that NO(3)(-) would be retained in N-rich streams. At the other three study sites, hydrogeologic controls limited or prevented infiltration of surface water into the streambed, and ground-water discharge contributed to NO(3)(-) loads. Our results also show that in these low hydrologic-gradient systems, storm and other high-flow events can be important factors for increasing surface-water movement into streambeds. PMID:18453426

  18. Surface-water hydrologic data for the Houston metropolitan area, Texas, water years 1990?95

    USGS Publications Warehouse

    Sneck-Fahrer, Debra A.; Liscum, Fred; East, Jeffrey W.

    2003-01-01

    Most of the Sacramento-San Joaquin Delta was leveed, drained, and converted to agricultural use by the 1930s. Land-surface elevations have since subsided by more than 20 feet in some areas. Subsidence increases the likelihood of levee failure and flooding, which, in turn, jeopardizes water delivery and water quality in the Delta. This is of major concern because the Delta supplies water to two-thirds of California. Previous research has shown that oxidation of peat soils is the primary cause of subsidence in the Delta. Therefore, a possible strategy for remedying this situation is to convert drained agricultural fields back to wetlands, which are flooded at least part of the year. Rehabilitation of wetlands would promote the growth of peat, thereby mitigating and possibly reversing subsidence. This report describes a study that evaluated this strategy. In three experimental enclosures or ponds, carbon inputs were measured in the form of plant biomass and outputs in the form of carbon dioxide (CO2) and methane (CH4) fluxes. Each of the ponds received one of the following water treatments: seasonally flooded, seasonally flooded and irrigated, or permanently flooded. Land-surface elevation, ground-water levels, and soil and air temperature also were measured. This report presents the data collected during the initial phase of the study, which ran from November 1992 through September 1995.

  19. Relationships between nutrient enrichment, pleurocerid snail density and trematode infection rate in streams

    USGS Publications Warehouse

    Ciparis, Serena; Iwanowicz, Deborah D.; Voshell, J. Reese, Jr.

    2013-01-01

    Summary 1. Nutrient enrichment is a widespread environmental problem in freshwater ecosystems. Eutrophic conditions caused by nutrient enrichment may result in a higher prevalence of infection by trematode parasites in host populations, due to greater resource availability for the molluscan first intermediate hosts. 2. This study examined relationships among land use, environmental variables indicating eutrophication, population density of the pleurocerid snail, Leptoxis carinata, and trematode infections. Fifteen study sites were located in streams within the Shenandoah River catchment (Virginia, U.S.A.), where widespread nutrient enrichment has occurred. 3. Snail population density had a weak positive relationship with stream water nutrient concentration. Snail population density also increased as human activities within stream catchments increased, but density did not continue to increase in catchments where anthropogenic disturbance was greatest. 4. Cercariae from five families of trematodes were identified in L. carinata, and infection rate was generally low (<10%). Neither total infection rate nor the infection rate of individual trematode types showed a positive relationship with snail population density, nutrients or land use. 5. There were statistically significant but weak relationships between the prevalence of infection by two trematode families and physical and biological variables. The prevalence of Notocotylidae was positively related to water depth, which may be related to habitat use by definitive hosts. Prevalence of Opecoelidae had a negative relationship with orthophosphate concentration and a polynomial relationship with chlorophyll a concentration. Transmission of Opecoelid trematodes between hosts may be inhibited by eutrophic conditions. 6. Leptoxis carinata appears to be a useful species for monitoring the biological effects of eutrophication and investigating trematode transmission dynamics in lotic systems.

  20. Trematode infections of the freshwater snail family Thiaridae in the Khek River, Thailand.

    PubMed

    Dechruksa, Wivitchuta; Krailas, Duangduen; Ukong, Suluck; Inkapatanakul, Wasin; Koonchornboon, Tunyarut

    2007-11-01

    The freshwater snail family Thiaridae was studied at five different locations: water sources for the Khek River, Thailand. Snail samples were collected by hand using counts per unit of time sampling method between December 2004 and October 2005. The physico-chemical quality of the water changed with the seasons and affected the sampling areas during both the dry season and the flood season. A total of 9,568 snail samples comprised of 14 species were found. These were 284 Tarebia granifera, 24 Melanoides tuberculata, 86 Thiara scabra, 3,295 Paracrostoma pseudosulcospira pseudosulcospira, 736 P. paludiformis paludiformis, 3,266 P. paludiformis dubiosa, 117 P. morrisoni, 304 Brotia (Brotia) binodosa binodosa, 1,250 B. (Brotia) microsculpta, 146 B. (Senckenbergia) wykoffi, 1 B. (Brotia) pagodula, 5 B. (Brotia) binodosa spiralis, 5 B. (Brotia) insolita and 49 B. (Brotia) manningi. The cercariae were investigated using shedding and crushing methods where they were categorized into two types and five species. The first type, Parapleurolophocercous cercariae, were comprised of Haplorchis pumilio Looss, 1899 and Centrocestus formosanus Nishigori, 1924. The second type, Xiphidiocercariae were comprised of Acanthatrium hitaense Koga, 1953, Loxogenoides bicolor Kaw, 1945 and Haematoloechus similis Looss, 1899. The cercarial infection rates in the above 5 species were 0.1% (5:9,568), 0.2% (15:9,568), 0.3% (24:9,568), 0.4% (37:9,568) and 0.1% (5:9,568), respectively. Five species of snails were susceptible to trematode infections. They were T. granifera, M. tuberculata, T. scabra, P. paludiformis paludiformis and B. (Senckenbergia) wykoffi; infections were found in 26.1% (74:284), 33.3% (8:24), 1.2% (1:86), 0.3% (2:736) and 0.7% (1:146), respectively. PMID:18613543

  1. Biological Control of Aquatic Pest Snails by the Black Carp Mylopharyngodon piceus

    Microsoft Academic Search

    Frida Ben-Ami; Joseph Heller

    2001-01-01

    Some freshwater snail species are severe pests to human health or agriculture. We tested the hypothesis that the fish Mylopharyngodon piceus, the black carp, may serve as a biological control agent of two pest snails, Physella acuta (a bank-dwelling snail) and Melanoides tuberculata (a substratum-dwelling snail). Experiments were carried out in the laboratory and under controlled field conditions. In the

  2. Paramphistomum daubneyi : the development of redial generations in the snail Lymnaea truncatula

    Microsoft Academic Search

    M. Abrous; D. Rondelaud; G. Dreyfuss

    1996-01-01

    Rediae of Paramphistomum daubneyi were counted and measured in Lymnaea truncatula to elucidate the variability in the numbers of free rediae and cercariae occurring between naturally infected snails and experimental single-miracidium infections. Experiments were performed using one miracidium per snail and snail raising was carried out at 20°C. Two redial generations succeeded each other in the snail until day 49.

  3. A SNAIL'S SPACE SETS A SNAIL'S PACE: MOVEMENT RATES OF LAVIGERIA GASTROPODS IN LAKE TANGANYIKA, EAST AFRICA

    E-print Network

    McIntyre, Peter

    A SNAIL'S SPACE SETS A SNAIL'S PACE: MOVEMENT RATES OF LAVIGERIA GASTROPODS IN LAKE TANGANYIKA gastropods are diverse and common in the benthos of Lake Tanganyika. We used in situ studies of marked of three closely related species of gastropods in Lake Tanganyika. In addition to potential interspecific

  4. Toxicity of Common Aquaculture Disinfectants to New Zealand Mud Snails and Mud Snail Toxicants to Rainbow Trout Eggs

    Microsoft Academic Search

    Randall W. Oplinger; Eric J. Wagner

    2009-01-01

    The New Zealand mud snail (NZMS) Potamopyrgus antipodarum is an invasive species that threatens North American fish populations. Establishment of NZMS in fish hatcheries is a concern because fish stocking practices could expedite the spread of the species. We evaluated the potential use of chemicals to remove snails that are inadvertently collected during egg take operations involving wild broodstock from

  5. Sediment copper bioavailability to freshwater snails in south Florida: risk implications for the Everglade snail kite ( Rostrhamus sociabilis plumbeus )

    Microsoft Academic Search

    Robert A. Frakes; Timothy A. Bargar; Emily A. Bauer

    2008-01-01

    Many properties being acquired as part of the Comprehensive Everglades Restoration Plan (CERP) are heavily contaminated with\\u000a copper. Estimated copper bioaccumulation in the Florida apple snail (Pomacea paludosa) has led to the prediction of risk to the Everglade snail kite (Rostrhamus sociabilis plumbeus) at some CERP projects. Field study results presented in this paper examine the relationship between copper levels

  6. Surface water sulfate dynamics in the northern Florida Everglades.

    PubMed

    Wang, Hongqing; Waldon, Michael G; Meselhe, Ehab A; Arceneaux, Jeanne C; Chen, Chunfang; Harwell, Matthew C

    2009-01-01

    Sulfate contamination has been identified as a serious environmental issue in the Everglades ecosystem. However, it has received less attention compared to P enrichment. Sulfate enters the Arthur R. Marshall Loxahatchee National Wildlife Refuge (Refuge), a remnant of the historic Everglades, in pumped stormwater discharges with a mean concentration of approximately 50 mg L(-1), and marsh interior concentrations at times fall below a detection limit of 0.1 mg L(-1). In this research, we developed a sulfate mass balance model to examine the response of surface water sulfate in the Refuge to changes in sulfate loading and hydrological processes. Meanwhile, sulfate removal resulting from microbial sulfate reduction in the underlying sediments of the marsh was estimated from the apparent settling coefficients incorporated in the model. The model has been calibrated and validated using long-term monitoring data (1995-2006). Statistical analysis indicated that our model is capable of capturing the spatial and temporal variations in surface water sulfate concentrations across the Refuge. This modeling work emphasizes the fact that sulfate from canal discharge is impacting even the interior portions of the Refuge, supporting work by other researchers. In addition, model simulations suggest a condition of sulfate in excess of requirement for microbial sulfate reduction in the Refuge. PMID:19244495

  7. An Ab Initio Based Potential Energy Surface for Water

    NASA Technical Reports Server (NTRS)

    Partridge, Harry; Schwenke, David W.; Langhoff, Stephen R. (Technical Monitor)

    1996-01-01

    We report a new determination of the water potential energy surface. A high quality ab initio potential energy surface (PES) and dipole moment function of water have been computed. This PES is empirically adjusted to improve the agreement between the computed line positions and those from the HITRAN 92 data base. The adjustment is small, nonetheless including an estimate of core (oxygen 1s) electron correlation greatly improves the agreement with experiment. Of the 27,245 assigned transitions in the HITRAN 92 data base for H2(O-16), the overall root mean square (rms) deviation between the computed and observed line positions is 0.125/cm. However the deviations do not correspond to a normal distribution: 69% of the lines have errors less than 0.05/cm. Overall, the agreement between the line intensities computed in the present work and those contained in the data base is quite good, however there are a significant number of line strengths which differ greatly.

  8. A robust, finite element model for hydrostatic surface water flows

    USGS Publications Warehouse

    Walters, R.A.; Casulli, V.

    1998-01-01

    A finite element scheme is introduced for the 2-dimensional shallow water equations using semi-implicit methods in time. A semi-Lagrangian method is used to approximate the effects of advection. A wave equation is formed at the discrete level such that the equations decouple into an equation for surface elevation and a momentum equation for the horizontal velocity. The convergence rates and relative computational efficiency are examined with the use of three test cases representing various degrees of difficulty. A test with a polar-quadrant grid investigates the response to local grid-scale forcing and the presence of spurious modes, a channel test case establishes convergence rates, and a field-scale test case examines problems with highly irregular grids.A finite element scheme is introduced for the 2-dimensional shallow water equations using semi-implicit methods in time. A semi-Lagrangian method is used to approximate the effects of advection. A wave equation is formed at the discrete level such that the equations decouple into an equation for surface elevation and a momentum equation for the horizontal velocity. The convergence rates and relative computational efficiency are examined with the use of three test cases representing various degrees of difficulty. A test with a polar-quadrant grid investigates the response to local grid-scale forcing and the presence of spurious modes, a channel test case establishes convergence rates, and a field-scale test case examines problems with highly irregular grids.

  9. Snails and their trails: the multiple functions of trail-following in gastropods.

    PubMed

    Ng, Terence P T; Saltin, Sara H; Davies, Mark S; Johannesson, Kerstin; Stafford, Richard; Williams, Gray A

    2013-08-01

    Snails are highly unusual among multicellular animals in that they move on a layer of costly mucus, leaving behind a trail that can be followed and utilized for various purposes by themselves or by other animals. Here we review more than 40 years of experimental and theoretical research to try to understand the ecological and evolutionary rationales for trail-following in gastropods. Data from over 30 genera are currently available, representing a broad taxonomic range living in both aquatic and terrestrial environments. The emerging picture is that the production of mucus trails, which initially was an adaptation to facilitate locomotion and/or habitat extension, has evolved to facilitate a multitude of additional functions. Trail-following supports homing behaviours, and provides simple mechanisms for self-organisation in groups of snails, promoting aggregation and thus relieving desiccation and predation pressures. In gastropods that copulate, trail-following is an important component in mate-searching, either as an alternative, or in addition to the release of water- or air-borne pheromones. In some species, this includes a capacity of males not only to identify trails of conspecifics but also to discriminate between trails laid by females and males. Notably, trail discrimination seems important as a pre-zygotic barrier to mating in some snail species. As production of a mucus trail is the most costly component of snail locomotion, it is also tempting to speculate that evolution has given rise to various ways to compensate for energy losses. Some snails, for example, increase energy intake by eating particles attached to the mucus of trails that they follow, whereas others save energy through reducing the production of their own mucus by moving over previously laid mucus trails. Trail-following to locate a prey item or a mate is also a way to save energy. While the rationale for trail-following in many cases appears clear, the basic mechanisms of trail discrimination, including the mechanisms by which many snails determine the polarity of the trail, are yet to be experimentally determined. Given the multiple functions of trail-following we propose that future studies should adopt an integrated approach, taking into account the possibility of the simultaneous occurrence of many selectively advantageous roles of trail-following behaviour in gastropods. We also believe that future opportunities to link phenotypic and genotypic traits will make possible a new generation of research projects in which gastropod trail-following, its multitude of functions and evolutionary trade-offs can be further elucidated. PMID:23374161

  10. Hydraulic "fracking": are surface water impacts an ecological concern?

    PubMed

    Burton, G Allen; Basu, Niladri; Ellis, Brian R; Kapo, Katherine E; Entrekin, Sally; Nadelhoffer, Knute

    2014-08-01

    Use of high-volume hydraulic fracturing (HVHF) in unconventional reservoirs to recover previously inaccessible oil and natural gas is rapidly expanding in North America and elsewhere. Although hydraulic fracturing has been practiced for decades, the advent of more technologically advanced horizontal drilling coupled with improved slickwater chemical formulations has allowed extensive natural gas and oil deposits to be recovered from shale formations. Millions of liters of local groundwaters are utilized to generate extensive fracture networks within these low-permeability reservoirs, allowing extraction of the trapped hydrocarbons. Although the technology is relatively standardized, the geographies and related policies and regulations guiding these operations vary markedly. Some ecosystems are more at risk from these operations than others because of either their sensitivities or the manner in which the HVHF operations are conducted. Generally, the closer geographical proximity of the susceptible ecosystem to a drilling site or a location of related industrial processes, the higher the risk of that ecosystem being impacted by the operation. The associated construction of roads, power grids, pipelines, well pads, and water-extraction systems along with increased truck traffic are common to virtually all HVHF operations. These operations may result in increased erosion and sedimentation, increased risk to aquatic ecosystems from chemical spills or runoff, habitat fragmentation, loss of stream riparian zones, altered biogeochemical cycling, and reduction of available surface and hyporheic water volumes because of withdrawal-induced lowering of local groundwater levels. The potential risks to surface waters from HVHF operations are similar in many ways to those resulting from agriculture, silviculture, mining, and urban development. Indeed, groundwater extraction associated with agriculture is perhaps a larger concern in the long term in some regions. Understanding the ecological impacts of these anthropogenic activities provides useful information for evaluations of potential HVHF hazards. Geographic information system-based modeling combined with strategic site monitoring has provided insights into the relative importance of these and other ecoregion and land-use factors in discerning potential HVHF impacts. Recent findings suggest that proper siting and operational controls along with strategic monitoring can reduce the potential for risks to aquatic ecosystems. Nevertheless, inadequate data exist to predict ecological risk at this time. The authors suggest considering the plausibility of surface water hazards associated with the various HVHF operations in terms of the ecological context and in the context of relevant anthropogenic activities. PMID:25044053

  11. Linear relationship between water wetting behavior and microscopic interactions of super-hydrophilic surfaces.

    PubMed

    Liu, Jian; Wang, Chunlei; Guo, Pan; Shi, Guosheng; Fang, Haiping

    2013-12-21

    Using molecular dynamics simulations, we show a fine linear relationship between surface energies and microscopic Lennard-Jones parameters of super-hydrophilic surfaces. The linear slope of the super-hydrophilic surfaces is consistent with the linear slope of the super-hydrophobic, hydrophobic, and hydrophilic surfaces where stable water droplets can stand, indicating that there is a universal linear behavior of the surface energies with the water-surface van der Waals interaction that extends from the super-hydrophobic to super-hydrophilic surfaces. Moreover, we find that the linear relationship exists for various substrate types, and the linear slopes of these different types of substrates are dependent on the surface atom density, i.e., higher surface atom densities correspond to larger linear slopes. These results enrich our understanding of water behavior on solid surfaces, especially the water wetting behaviors on uncharged super-hydrophilic metal surfaces. PMID:24359382

  12. Linear relationship between water wetting behavior and microscopic interactions of super-hydrophilic surfaces

    NASA Astrophysics Data System (ADS)

    Liu, Jian; Wang, Chunlei; Guo, Pan; Shi, Guosheng; Fang, Haiping

    2013-12-01

    Using molecular dynamics simulations, we show a fine linear relationship between surface energies and microscopic Lennard-Jones parameters of super-hydrophilic surfaces. The linear slope of the super-hydrophilic surfaces is consistent with the linear slope of the super-hydrophobic, hydrophobic, and hydrophilic surfaces where stable water droplets can stand, indicating that there is a universal linear behavior of the surface energies with the water-surface van der Waals interaction that extends from the super-hydrophobic to super-hydrophilic surfaces. Moreover, we find that the linear relationship exists for various substrate types, and the linear slopes of these different types of substrates are dependent on the surface atom density, i.e., higher surface atom densities correspond to larger linear slopes. These results enrich our understanding of water behavior on solid surfaces, especially the water wetting behaviors on uncharged super-hydrophilic metal surfaces.

  13. Adsorption of water on the KNTN (0 0 1) surface: A density functional theory study

    NASA Astrophysics Data System (ADS)

    Wang, Wenhan; Shen, Yanqing; Wang, Xiaoou; Zhou, Zhongxiang; Fei, Weidong

    2014-04-01

    We present a density functional theory study of water adsorption on K1-yNayTa1-xNbxO3 (KNTN) surface terminations. The adsorption configuration and energy are determined and the bond formation between water molecule and KNTN surface are investigated by analysis of difference electron density and partial density of states. Our calculations reveal that the energetically favorable configurations for water monomer adsorption is at the K-Na bridge site on the K(Na)O-termination and the Nb top site on the Ta(Nb)O2-termination. With the coverage increasing, the water-surface interaction per water molecule decreases because of the formation of interwater hydrogen bonds, whereas the surface geometry becomes more roughness. The variation of bandgap for water adsorbed KNTN surface is also studied. We find that the interaction between water and surface would lead to a bandgap increase of KNTN surface, which is correlated to the electrons density redistribution.

  14. Movement of Amazon surface water from time-variable satellite gravity measurements and implications for water cycle parameters in land surface models

    Microsoft Academic Search

    Shin-Chan Han; In-Young Yeo; Doug Alsdorf; Paul Bates; Jean-Paul Boy; Hyungjun Kim; Taikan Oki; Matthew Rodell

    2010-01-01

    The large-scale observations of terrestrial water storage from GRACE satellites over the Amazon are analyzed with land surface model (LSM) outputs of runoff and soil moisture. A simple yet effective runoff routing method based on a continuity equation is implemented to model horizontal transport of surface water within the Amazon basin. The GRACE observations are analyzed separately for soil moisture

  15. Index of surface-water stations in Texas, January 1986

    USGS Publications Warehouse

    Carrillo, E.R.; Buckner, H.D.; Rawson, Jack

    1986-01-01

    As of January 1, 1986, the surface-water data-collection network in Texas operated by the U.S. Geological Survey included 386 streamflow, 87 reservoir-contents, 33 stage, 10 crest-stage partial-record, 8 periodic discharge through range, 38 flood-hydrograph partial-record, 11 flood-profile partial-record , 36 low-flow partial-record 2 tide-level, 45 daily chemical-quality, 23 continuous-recording water-quality, 97 periodic biological, 19 lake surveys, 174 periodic organic- and (or) nutrient, 4 periodic insecticide, 58 periodic pesticide, 22 automatic sampler, 157 periodic minor elements, 141 periodic chemical-quality, 108 periodic physical-organic, 14 continuous-recording three- or four-parameter water-quality, 3 sediment, 39 periodic sediment, 26 continuous-recording temperature, and 37 national stream-quality accounting network stations were in operation. Tables describing the station location, type of data collected, and place where data are available are included, as well as maps showing the location of most of the stations. (USGS)

  16. On leakage and seepage of CO 2 from geologic storage sites into surface water

    Microsoft Academic Search

    C. M. Oldenburg; J. L. Lewicki

    2006-01-01

    Geologic carbon sequestration is the capture of anthropogenic carbon dioxide (CO2) and its storage in deep geologic formations. The processes of CO2 seepage into surface water after migration through water-saturated sediments are reviewed. Natural CO2 and CH4 fluxes are pervasive in surface-water environments and are good analogues to potential leakage and seepage of CO2. Buoyancy-driven bubble rise in surface water

  17. Porous ceramic membrane with superhydrophobic and superoleophilic surface for reclaiming oil from oily water

    NASA Astrophysics Data System (ADS)

    Su, Changhong; Xu, Youqian; Zhang, Wei; Liu, Yang; Li, Jun

    2012-01-01

    A porous ceramic tube with superhydrophobic and superoleophilic surface was fabricated by sol-gel and then surface modification with polyurethane-polydimethysiloxane, and an oil-water separator based on the porous ceramic tube was erected to characterize superhydrophobic and superoleophilic surface's separation efficiency and velocity when being used to reclaim oil from oily water and complex oily water containing clay particle. The separator is fit for reclaiming oil from oily water.

  18. Formation of mutagenic activity during surface water preozonization and its removal in drinking water treatment

    SciTech Connect

    Van Hoof, F.; Janssens, J.G.; Van Dijck, H.

    1985-01-01

    The influence of preozonization, coagulation and double layer filtration on formation and removal of mutagenic activity was studied using XAD-8 extracts collected from neutral and acidic solutions and assaying them in the Salmonella typhimurium microsomal assay. Preozonization of surface water produced direct acting frame shift mutagens which were adsorbed on XAD-8 from neutral solutions. This phenomenon was shown to be dependent on the ozone dose applied. Coagulation with different chemicals and subsequent direct filtration partially reduced the mutagenic activity.

  19. A Surface Water Protection Assessment Tool that uses Digital Elevation Models1 Darwin L. Sorensen

    E-print Network

    Tarboton, David

    .g., petroleum product contaminated ground water or septic system contaminated ground water) on surface water of pollution under various storm intensities can be analyzed. The influences of shallow ground water quality (e-22, 2003 #12;2 Introduction Source water assessments provide information about potential contamination

  20. Surface Water and Groundwater Relationships in Nebraska James Goeke, Research Hydrogeologist, School of Natural Resources/Conservation and

    E-print Network

    Nebraska-Lincoln, University of

    between ground water and surface water is part of the water cycle in Nebraska. When there is precipitationSurface Water and Groundwater Relationships in Nebraska James Goeke, Research Hydrogeologist between ground water and surface water has been poorly understood and as a result a contentious issue

  1. First record of the invasive snail Melanoides tuberculatus (Gastropoda: Prosobranchia: Thiaridae) in the Paranã River Basin, GO, Brazil.

    PubMed

    Rocha-Miranda, F; Martins-Silva, M J

    2006-11-01

    The Thiarid snail Melanoides tuberculatus (Müller, 1774), native to Asia and East Africa was recorded for the first time in the Paranã River basin, Goiás State. There is no evidence concerning introduction vectors but aquarium releases is the most probable vector. Specimens were collected at three different water bodies after twenty-seven rivers were investigated. The possible spread of this species to other habitats and potential effects on native thermal water communities are discussed. PMID:17299947

  2. High resolution remote sensing of water surface patterns

    NASA Astrophysics Data System (ADS)

    Woodget, A.; Visser, F.; Maddock, I.; Carbonneau, P.

    2012-12-01

    The assessment of in-stream habitat availability within fluvial environments in the UK traditionally includes the mapping of patterns which appear on the surface of the water, known as 'surface flow types' (SFTs). The UK's River Habitat Survey identifies ten key SFTs, including categories such as rippled flow, upwelling, broken standing waves and smooth flow. SFTs result from the interaction between the underlying channel morphology, water depth and velocity and reflect the local flow hydraulics. It has been shown that SFTs can be both biologically and hydraulically distinct. SFT mapping is usually conducted from the river banks where estimates of spatial coverage are made by eye. This approach is affected by user subjectivity and inaccuracies in the spatial extent of mapped units. Remote sensing and specifically the recent developments in unmanned aerial systems (UAS) may now offer an alternative approach for SFT mapping, with the capability for rapid and repeatable collection of very high resolution imagery from low altitudes, under bespoke flight conditions. This PhD research is aimed at investigating the mapping of SFTs using high resolution optical imagery (less than 10cm) collected from a helicopter-based UAS flown at low altitudes (less than 100m). This paper presents the initial findings from a series of structured experiments on the River Arrow, a small lowland river in Warwickshire, UK. These experiments investigate the potential for mapping SFTs from still and video imagery of different spatial resolutions collected at different flying altitudes and from different viewing angles (i.e. vertical and oblique). Imagery is processed using 3D mosaicking software to create orthophotos and digital elevation models (DEM). The types of image analysis which are tested include a simple, manual visual assessment undertaken in a GIS environment, based on the high resolution optical imagery. In addition, an object-based image analysis approach which makes use of the spectral and textural images properties is tested using Definiens eCognition software. Where possible, the DEM of the water surface topography is also analysed for identifying SFTs. The site is revisited in order to assess the temporal variability of SFTs as relating to changes in flow level, and the potential for variability in identifying SFTs from imagery as relating to changes in lighting and weather conditions.

  3. A cellular automata approach for modeling surface water runoff

    NASA Astrophysics Data System (ADS)

    Jozefik, Zoltan; Nanu Frechen, Tobias; Hinz, Christoph; Schmidt, Heiko

    2015-04-01

    This abstract reports the development and application of a two-dimensional cellular automata based model, which couples the dynamics of overland flow, infiltration processes and surface evolution through sediment transport. The natural hill slopes are represented by their topographic elevation and spatially varying soil properties infiltration rates and surface roughness coefficients. This model allows modeling of Hortonian overland flow and infiltration during complex rainfall events. An advantage of the cellular automata approach over the kinematic wave equations is that wet/dry interfaces that often appear with rainfall overland flows can be accurately captured and are not a source of numerical instabilities. An adaptive explicit time stepping scheme allows for rainfall events to be adequately resolved in time, while large time steps are taken during dry periods to provide for simulation run time efficiency. The time step is constrained by the CFL condition and mass conservation considerations. The spatial discretization is shown to be first-order accurate. For validation purposes, hydrographs for non-infiltrating and infiltrating plates are compared to the kinematic wave analytic solutions and data taken from literature [1,2]. Results show that our cellular automata model quantitatively accurately reproduces hydrograph patterns. However, recent works have showed that even through the hydrograph is satisfyingly reproduced, the flow field within the plot might be inaccurate [3]. For a more stringent validation, we compare steady state velocity, water flux, and water depth fields to rainfall simulation experiments conducted in Thies, Senegal [3]. Comparisons show that our model is able to accurately capture these flow properties. Currently, a sediment transport and deposition module is being implemented and tested. [1] M. Rousseau, O. Cerdan, O. Delestre, F. Dupros, F. James, S. Cordier. Overland flow modeling with the Shallow Water Equation using a well balanced numerical scheme: Adding efficiency or sum more complexity?. 2012. [2] Fritz R. Fiedler, J. A. Ramirez. A numerical method for simulating discontinuous shallow flow over an infiltrating surface. In. J. Numer. Mech. Fluids 200: 32: 219-240. [3] C. Mügler, O. Planchon, J. Patin, S. Weill, N. Silvera, P. Richard, E. Mouche. Comparison of Roughness models to simulate overland flow and tracer transport experiments under simulated rainfall at plot scale. Journal of Hydrology. 402 (2011) 25-40.

  4. Phenotypic clines, plasticity, and morphological trade-offs in an intertidal snail.

    PubMed

    Trussell, G C

    2000-02-01

    Understanding the genetic and environmental bases of phenotypic variation and how they covary on local and broad geographic scales is an important goal of evolutionary ecology. Such information can shed light on how organisms adapt to different and changing environments and how life-history trade-offs arise. Surveys of phenotypic variation in 25 Littorina obtusata populations across an approximately 400-km latitudinal gradient in the Gulf of Maine revealed pronounced clines. The shells of snails from northern habitats weighed less and were thinner and weaker in compression than those of conspecifics from southern habitats. In contrast, body size (as measured by soft tissue mass) followed an opposite pattern; northern snails weighed more than southern snails. A reciprocal transplant between a northern and southern habitat revealed substantial plasticity in shell form and body mass and their respective measures of growth. Southern snails transplanted to the northern habitat produced lighter, thinner shells and more body mass than controls raised in their native habitat. In contrast, northern snails transplanted to the southern site produced heavier, thicker shells and less body mass than controls raised in their native habitat. Patterns of final phenotypic variation for all traits were consistent with cogradient variation (i.e., a positive covariance between genetic and environmental influences). However, growth in shell traits followed a countergradient pattern (i.e., a negative covariance between genetic and environmental influences). Interestingly, body growth followed a cogradient pattern, which may reflect constraints imposed by cogradient variation in final shell size and thickness. This result suggests the existence of potential life-history trade-offs associated with increased shell production. Differences in L. obtusata shell form, body mass, and their respective measures of growth are likely induced by geographic differences in both water temperature and the abundance of an invading crab predator (Carcinus maenas). Water temperatures averaged 6.8 degrees C warmer during the transplant experiment and C. maenas abundance is greater in the southern Gulf of Maine. Because both increased water temperature and crab effluent affect shell form in the same way, future experiments are needed to determine the relative importance of each. Nevertheless, it is clear that phenotypic plasticity has an important role in producing geographic variation in L. obtusata shell form. Moreover, the evolution of phenotypic plasticity in L. obtusata and other marine gastropods may be driven by architectural constraints imposed by shell form on body mass and growth. PMID:10937192

  5. Elevated CO2 affects shell dissolution rate but not calcification rate in a marine snail.

    PubMed

    Nienhuis, Sarah; Palmer, A Richard; Harley, Christopher D G

    2010-08-22

    As CO(2) levels increase in the atmosphere, so too do they in the sea. Although direct effects of moderately elevated CO(2) in sea water may be of little consequence, indirect effects may be profound. For example, lowered pH and calcium carbonate saturation states may influence both deposition and dissolution rates of mineralized skeletons in many marine organisms. The relative impact of elevated CO(2) on deposition and dissolution rates are not known for many large-bodied organisms. We therefore tested the effects of increased CO(2) levels--those forecast to occur in roughly 100 and 200 years--on both shell deposition rate and shell dissolution rate in a rocky intertidal snail, Nucella lamellosa. Shell weight gain per day in live snails decreased linearly with increasing CO(2) levels. However, this trend was paralleled by shell weight loss per day in empty shells, suggesting that these declines in shell weight gain observed in live snails were due to increased dissolution of existing shell material, rather than reduced production of new shell material. Ocean acidification may therefore have a greater effect on shell dissolution than on shell deposition, at least in temperate marine molluscs. PMID:20392726

  6. Evidence for specific genotype-dependent immune priming in the lophotrochozoan Biomphalaria glabrata snail.

    PubMed

    Portela, Julien; Duval, David; Rognon, Anne; Galinier, Richard; Boissier, Jérôme; Coustau, Christine; Mitta, Guillaume; Théron, André; Gourbal, Benjamin

    2013-01-01

    Historically, the prevailing view in the field of invertebrate immunity was that invertebrates that do not possess acquired adaptive immunity rely on innate mechanisms with low specificity and no memory. Several recent studies have shaken this paradigm and suggested that the immune defenses of invertebrates are more complex and specific than previously thought. Mounting evidence has shown that at least some invertebrates (mainly Ecdysozoa) show high levels of specificity in their immune responses to different pathogens, and that subsequent reexposure may result in enhanced protection (recently called 'immune priming'). Here, we investigated immune priming in the Lophotrochozoan snail species Biomphalaria glabrata, following infection by the trematode pathogen Schistosoma mansoni. We confirmed that snails were protected against a secondary homologous infection whatever the host strain. We then investigated how immune priming occurs and the level of specificity of B. glabrata immune priming. In this report we confirmed that immune priming exists and we identified a genotype-dependent immune priming in the fresh-water snail B. glabrata. PMID:23343530

  7. Seasonal population densities of snails transmitting urinary and intestinal schistosomiasis in Lusaka, Zambia.

    PubMed

    Hira, P R

    1975-03-01

    The two molluscan intermediate hosts of S. haematobium schistosomiasis: Bulinus africanus and Bulinus globosus, were found most commonly in habitats that retained water for a substantial part of the year rather than in temporary rain-filled pools. Biomphalaria pfeifferi which transmits S. mansoni were found principally in streams and impoundments like dams but scarce in rivers. In a permanent habitat, the peak density of snails was between the warm, dry months of August and September while in a temporary habitat B. (Physopsis) sp. were most abundant towards the end of the rainy season in March and April. The influence of rainfall and the prevailing the temperature on the fluctuations in the density of snails populations is considered. Further, the low infection rate in snails found in the field is discussed in relation to the critical effect of temperature on this feature. The problem of increasing migration of rural inhabitants to the peri-urban areas and the possible escalation of prevalence rates is considered in relation to the control measures that may be instituted in view of the substantial body of base-line data now available to effect focal control. PMID:1169833

  8. Spatial mosaic evolution of snail defensive traits

    PubMed Central

    Johnson, Steven G; Hulsey, C Darrin; de León, Francisco J García

    2007-01-01

    Background Recent models suggest that escalating reciprocal selection among antagonistically interacting species is predicted to occur in areas of higher resource productivity. In a putatively coevolved interaction between a freshwater snail (Mexipyrgus churinceanus) and a molluscivorous cichlid (Herichthys minckleyi), we examined three components of this interaction: 1) spatial variation in two putative defensive traits, crushing resistance and shell pigmentation; 2) whether abiotic variables or frequency of molariform cichlids are associated with spatial patterns of crushing resistance and shell pigmentation and 3) whether variation in primary productivity accounted for small-scale variation in these defensive traits. Results Using spatial autocorrelation to account for genetic and geographic divergence among populations, we found no autocorrelation among populations at small geographic and genetic distances for the two defensive traits. There was also no correlation between abiotic variables (temperature and conductivity) and snail defensive traits. However, crushing resistance and frequency of pigmented shells were negatively correlated with molariform frequency. Crushing resistance and levels of pigmentation were significantly higher in habitats dominated by aquatic macrophytes, and both traits are phenotypically correlated. Conclusion Crushing resistance and pigmentation of M. churinceanus exhibit striking variation at small spatial scales often associated with differences in primary productivity, substrate coloration and the frequency of molariform cichlids. These local geographic differences may result from among-habitat variation in how resource productivity interacts to promote escalation in prey defenses. PMID:17397540

  9. Biological control of the snail hosts of Schistosoma mansoni in the Caribbean area using Thiara spp.

    PubMed

    Pointier, J P; McCullough, F

    1989-05-01

    Field observations and experiments using thiarid snails as competitors of Biomphalaria spp., potential intermediate hosts of Schistosoma mansoni in the Caribbean area, are reviewed. The parthenogenetic snails, Thiara granifera and T. (= Melanoides) tuberculata, were introduced to the Neotropical area in recent decades. In numerous islands and countries, these oriental species have demonstrated their capacity to colonize rapidly and densely many types of habitats while at the same time reducing and even eliminating populations of Biomphalaria spp. The results of field experiments, carried out in several Caribbean islands, have shown the efficiency as well as the limitations of T. tuberculata as a competitor of B. glabrata and B. straminea. In St. Lucia, B. glabrata was apparently eliminated from marshes and streams, 6 to 22 months after the introduction of the competitor. In Martinique, T. tuberculata was introduced into two groups of water-cress beds which constituted the last transmission sites of schistosomiasis on the island. In just less than three years after the introduction of the competitor, both B. glabrata and B. straminea have been eliminated from the transmission sites. In Guadeloupe, several introductions have been carried out in different types of habitat such as permanent ponds, canals, streams and temporary marshes. The findings of all field experiments have indicated that thiarid snails as competitors of pulmonates are favoured by the presence of permanent and stable habitats, preferably shallow, with emergent plants and well oxygenated. On the other hand, the competitor snails are at a disadvantage in waterbodies which are temporary, extremely deep, poorly oxygenated or with a dense mat of floating aquatic vegetation.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:2566267

  10. Estimated ecological effects of triazine use of surface waters

    SciTech Connect

    Mercurio, S.D.

    1996-10-01

    Based on the current intensive use of triazines in agriculture in the northern portions of the Midwest, ecological impacts have been evaluated in surface waters. Considerations from application methods to stream concentrations predict a range of impacts using current toxicity models. Standard {open_quotes}static{close_quotes} LC{sub 50}s predict only algal mortality at peak runoff, while laboratory flow-through systems indicate seasonal impacts on primary stream productivity. Mesocosms further observe indirect effects on numerous species during the year. Microcosm and flow-through wetland mesocosm studies indicate primary effects during the growing season on algal populations, magnified by zooplankton bloom stresses and indirect effects on dissolved oxygen and nutrient concentrations. If the river continuum model is considered in combination with triazine concentrations, clear untoward effects on stream ecosystems occur with current practices. The use of banding application or other remediation techniques for positive ecological and economic gains as proven alternatives to current uses are encouraged.

  11. Experimental study of spatiotemporally localized surface gravity water waves.

    PubMed

    Chabchoub, A; Akhmediev, N; Hoffmann, N P

    2012-07-01

    We present experimental results on the study of spatiotemporally localized surface wave events on deep water that can be modeled using the Peregrine breather solution of the nonlinear Schrödinger equation. These are often considered as prototypes of oceanic rogue waves that can focus wave energy into a single wave packet. For small steepness values of the carrier gravity waves the Peregrine breathers are relatively wide, thus providing an excellent agreement between the theory and experimental results. For larger steepnesses the focusing leads to temporally and spatially shorter events. Nevertheless, agreement between measurements and the Peregrine breather theory remains reasonably good, with discrepancies of modulation gradients and spatiotemporal symmetries being tolerable. Lifetimes and travel distances of the spatiotemporally localized wave events determined from the experiment are in good agreement with the theory. PMID:23005529

  12. Application of surface geophysics to ground-water investigations

    USGS Publications Warehouse

    Zohdy, Adel A.R.; Eaton, Gordon P.; Mabey, Don R.

    1974-01-01

    This manual reviews the standard methods of surface geophysics applicable to ground-water investigations. It covers electrical methods, seismic and gravity methods, and magnetic methods. The general physical principles underlying each method and its capabilities and limitations are described. Possibilities for non-uniqueness of interpretation of geophysical results are noted. Examples of actual use of the methods are given to illustrate applications and interpretation in selected geohydrologic environments. The objective of the manual is to provide the hydrogeologist with a sufficient understanding of the capabilities, imitations, and relative cost of geophysical methods to make sound decisions as to when to use of these methods is desirable. The manual also provides enough information for the hydrogeologist to work with a geophysicist in designing geophysical surveys that differentiate significant hydrogeologic changes.

  13. Does forest fire effect chemical composition of surface water

    SciTech Connect

    Sanders, A.T. (Illinois State Univ., Normal, IL (United States). Dept. of Geography and Geology)

    1992-01-01

    Chemical Data for stream drainages in Yellowstone National Park area have been examined for trends associated with the 1988 burn. Limited pre-fire data make assessment difficult. Data from the Snake River (at maximum recorded discharge) suggest that TDS decreases, total Nitrogen remains constant and total Phosphorus increases from pre-fire (and very dry conditions) to post-fire (and more normal conditions). To test these apparent trends post-fire data from adjacent valleys (Jones Creek, burned; Crow Creek, unburned) were compared. Each shows a decrease in TDS, similar nearly constant total Nitrogen and an increase in total Phosphorus. Although year to year changes in surface water seem greater from the burned valley, the data from the unburned valley show similar trends. Therefore these data do not clearly distinguish trends resulting solely from the burn.

  14. Water accounting for conjunctive groundwater/surface water management: case of the Singkarak Ombilin River basin, Indonesia

    NASA Astrophysics Data System (ADS)

    Peranginangin, Natalia; Sakthivadivel, Ramaswamy; Scott, Norman R.; Kendy, Eloise; Steenhuis, Tammo S.

    2004-06-01

    Because water shortages limit development in many parts of the world, a systematic approach is needed to use water more productively. To address this need, Molden and Sakthivadivel [Water Resour. Dev. 15 (1999) 55-71] developed a water-accounting procedure for analyzing water use patterns and tradeoffs between users. Their procedure treats groundwater and surface water as a single domain. We adapted this procedure to account for groundwater and surface water components separately, and applied the adapted procedure to the Singkarak-Ombilin River basin, Indonesia, where groundwater is a significant part of the overall water balance. Since 1998, a substantial proportion of water has been withdrawn from Singkarak Lake and diverted out of the basin, resulting in significant impacts on downstream water users and the lake ecosystem. Based on 15-20 years (1980-1999) of hydrometeorological, land use, soil, and other relevant data, a simple groundwater balance model was developed to generate the hydrogeologic information needed for the water-accounting procedure. The water-accounting procedure was then used to evaluate present and potential future water use performance in the basin. By considering groundwater and surface water components separately, a more realistic estimate of water availability was calculated than could be obtained by lumping these components together. Results show that the diversion of 37 m 3/s from Singkarak Lake increases the amount of water that is not available for other uses, such as for irrigation, from 57-81 to 81-95% of total water available in the basin. The new water accounting procedure also demonstrates the viability of increasing downstream water supply and water use performance during the dry months (June-September). For example, by increasing irrigation during the wet months (January-April) or tapping water from a shallow, unconfined aquifer during the dry months, while keep maintaining sustainable groundwater levels.

  15. Prevalence of Escherichia coli O157:H7 and Salmonella spp. in surface waters of southern

    E-print Network

    Selinger, Brent

    Prevalence of Escherichia coli O157:H7 and Salmonella spp. in surface waters of southern Alberta and Salmonella spp. in surface water within the basin. This study is the first of its kind to identify E. coli O and Salmonella spp. in water samples was 0.9% (n = 1483) and 6.2% (n = 1429), respectively. While data examined

  16. Water at the Surfaces of Aligned Phospholipid Multibilayer Model Membranes Probed with Ultrafast Vibrational

    E-print Network

    Fayer, Michael D.

    Water at the Surfaces of Aligned Phospholipid Multibilayer Model Membranes Probed with Ultrafast@stanford.edu Abstract: The dynamics of water at the surface of artificial membranes composed of aligned multibilayers pump-probe spectroscopy. The experiments are performed at various hydration levels, x ) 2 - 16 water

  17. Interpretation of pesticide contamination monitoring data in surface water in France

    E-print Network

    Paris-Sud XI, Université de

    Interpretation of pesticide contamination monitoring data in surface water in France Christine requires a monitoring of pesticide contamination in surface water. In France, 15 million analyses have been of drinking water standards, or specific knowledge of pesticide contamination) and area of concern, leading

  18. Measurement of the forces between gold surfaces in water by atomic force microscopy

    E-print Network

    La Rosa, Andres H.

    Measurement of the forces between gold surfaces in water by atomic force microscopy Simon Biggs gold surface and a gold-coated silica sphere have been measured in water using an atomic force of the Hamaker function (including retardation) for gold/water/gold. The best fit to the experimental data yields

  19. Total maximum daily load (TMDL) approach to surface water quality management: concepts, issues, and applications

    Microsoft Academic Search

    Amin Elshorbagy; Ramesh S. V. Teegavarapu; Lindell Ormsbee

    2005-01-01

    The total maximum daily load (TMDL) approach is an emerging paradigm in surface water quality manage- ment and has been adopted and applied in many states in the US. The paper explains the conceptual development of the general TMDL process for surface water quality management of three water quality impairment constituents, namely, nutrients, pathogens, and acid load. The application of

  20. Nutrient Loss in Runoff from Turf: Effect on Surface Water Quality

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Excess nutrients in surface waters may result in enhanced algal blooms and plant growth that can lead to eutrophication and a decline in water quality. The applicatin of fertilizer to golf courses may be a source of nutrients to surface waters. Runoff studies were conducted to measure applied nitrog...