Four alpine streams were monitored to continuously collect stream temperature and streamflow for periods ranging from a week to a year. In a small stream in the Colorado Rockies, diurnal variations in both stream temperature and streamflow were significantly greater in losing reaches than in gaining reaches, with minimum streamflow losses occurring early in the day and maximum losses occurring early in the evening. Using measured stream temperature changes, diurnal streambed infiltration rates were predicted to increase as much as 35% during the day (based on a heat and water transport groundwater model), while the measured increase in streamflow loss was 40%. For two large streams in the Sierra Nevada Mountains, annual stream temperature variations ranged from 0° to 25°C. In summer months, diurnal stream temperature variations were 30–40% of annual stream temperature variations, owing to reduced streamflows and increased atmospheric heating. Previous reports document that one Sierra stream site generally gains groundwater during low flows, while the second Sierra stream site may lose water during low flows. For August the diurnal streamflow variation was 11% at the gaining stream site and 30% at the losing stream site. On the basis of measured diurnal stream temperature variations, streambed infiltration rates were predicted to vary diurnally as much as 20% at the losing stream site. Analysis of results suggests that evapotranspiration losses determined diurnal streamflow variations in the gaining reaches, while in the losing reaches, evapotranspiration losses were compounded by diurnal variations in streambed infiltration. Diurnal variations in stream temperature were reduced in the gaining reaches as a result of discharging groundwater of relatively constant temperature. For the Sierra sites, comparison of results with those from a small tributary demonstrated that stream temperature patterns were useful in delineating discharges of bank storage following dam releases. Direct coupling may have occurred between streamflow and stream temperature for losing stream reaches, such that reduced streamflows facilitated increased afternoon stream temperatures and increased afternoon stream temperatures induced increased streambed losses, leading to even greater increases in both stream temperature and streamflow losses.
","language":"English","publisher":"American Geophysical Union","doi":"10.1029/98WR00998","usgsCitation":"Constantz, J., 1998, Interaction between stream temperature, streamflow, and groundwater exchanges in alpine streams: Water Resources Research, v. 34, no. 7, p. 1609-1615, https://doi.org/10.1029/98WR00998.","productDescription":"7 p.","startPage":"1609","endPage":"1615","costCenters":[{"id":589,"text":"Toxic Substances Hydrology Program","active":true,"usgs":true}],"links":[{"id":230276,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"34","issue":"7","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505a3cace4b0c8380cd62f38","contributors":{"authors":[{"text":"Constantz, James E. 0000-0002-4062-2096 jconstan@usgs.gov","orcid":"https://orcid.org/0000-0002-4062-2096","contributorId":1962,"corporation":false,"usgs":true,"family":"Constantz","given":"James E.","email":"jconstan@usgs.gov","affiliations":[{"id":438,"text":"National Research Program - Western Branch","active":true,"usgs":true}],"preferred":true,"id":387797,"contributorType":{"id":1,"text":"Authors"},"rank":1}]}} ,{"id":70020360,"text":"70020360 - 1998 - Tritium-helium 3 dating under complex conditions in hydraulically stressed areas of a buried-valley aquifer","interactions":[],"lastModifiedDate":"2018-03-16T10:35:39","indexId":"70020360","displayToPublicDate":"1998-01-01T00:00:00","publicationYear":"1998","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":3722,"text":"Water Resources Research","onlineIssn":"1944-7973","printIssn":"0043-1397","active":true,"publicationSubtype":{"id":10}},"title":"Tritium-helium 3 dating under complex conditions in hydraulically stressed areas of a buried-valley aquifer","docAbstract":"The 3H-3He dating method is applied in a buried-valley aquifer near Dayton, Ohio. The study area is large, not all sampling locations lie along well-defined flow paths, and existing wells with variable screen lengths and diameters are used. Reliable use of the method at this site requires addressing several complications: (1) The flow system is disturbed because of high pumping rates and induced infiltration; (2) tritium contamination is present in several areas of the aquifer; and (3) radiogenic helium concentrations are elevated in a significant number of the wells. The 3H-3He ages are examined for self-consistency by comparing the reconstructed tritium evolution to the annual weighted tritium measured in precipitation; deviations result from dispersion, tritium contamination, and mixing. 3H-3He ages are next examined for consistency with chlorofluorocarbon ages; the agreement is poor because of degradation of CFCs. Finally, the 3H-3He ages are examined for consistency with the current understanding of local hydrologic processes; the ages are generally supported by hydrogeologic data and the results of groundwater flow modeling coupled with particle-tracking analyses.
","language":"English","publisher":"American Geophysical Union","doi":"10.1029/97WR03322","usgsCitation":"Shapiro, S.D., Rowe, G.L., Schlosser, P., Ludin, A., and Stute, M., 1998, Tritium-helium 3 dating under complex conditions in hydraulically stressed areas of a buried-valley aquifer: Water Resources Research, v. 34, no. 5, p. 1165-1180, https://doi.org/10.1029/97WR03322.","productDescription":"16 p.","startPage":"1165","endPage":"1180","costCenters":[],"links":[{"id":487337,"rank":1,"type":{"id":40,"text":"Open Access Publisher Index Page"},"url":"https://doi.org/10.1029/97wr03322","text":"Publisher Index Page"},{"id":231367,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"country":"United States","state":"Ohio","city":"Dayton","volume":"34","issue":"5","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505bb874e4b08c986b32787e","contributors":{"authors":[{"text":"Shapiro, Stephanie Dunkle","contributorId":82738,"corporation":false,"usgs":true,"family":"Shapiro","given":"Stephanie","email":"","middleInitial":"Dunkle","affiliations":[],"preferred":false,"id":385954,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Rowe, Gary L. glrowe@usgs.gov","contributorId":1779,"corporation":false,"usgs":true,"family":"Rowe","given":"Gary","email":"glrowe@usgs.gov","middleInitial":"L.","affiliations":[],"preferred":true,"id":385952,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Schlosser, Peter","contributorId":50936,"corporation":false,"usgs":true,"family":"Schlosser","given":"Peter","email":"","affiliations":[],"preferred":false,"id":385955,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Ludin, Andrea","contributorId":93232,"corporation":false,"usgs":true,"family":"Ludin","given":"Andrea","email":"","affiliations":[],"preferred":false,"id":385951,"contributorType":{"id":1,"text":"Authors"},"rank":4},{"text":"Stute, Martin","contributorId":131127,"corporation":false,"usgs":false,"family":"Stute","given":"Martin","email":"","affiliations":[{"id":7254,"text":"Columbia University - Lamont Doherty Earth Observatory","active":true,"usgs":false}],"preferred":false,"id":385953,"contributorType":{"id":1,"text":"Authors"},"rank":5}]}} ,{"id":70020341,"text":"70020341 - 1998 - Classification of surface types using SIR-C/X-SAR, Mount Everest Area, Tibet","interactions":[],"lastModifiedDate":"2017-04-07T15:04:24","indexId":"70020341","displayToPublicDate":"1998-01-01T00:00:00","publicationYear":"1998","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":2317,"text":"Journal of Geophysical Research E: Planets","active":true,"publicationSubtype":{"id":10}},"title":"Classification of surface types using SIR-C/X-SAR, Mount Everest Area, Tibet","docAbstract":"Imaging radar is a promising tool for mapping snow and ice cover in alpine regions. It combines a high-resolution, day or night, all-weather imaging capability with sensitivity to hydrologic and climatic snow and ice parameters. We use the spaceborne imaging radar-C/X-band synthetic aperture radar (SIR-C/X-SAR) to map snow and glacial ice on the rugged north slope of Mount Everest. From interferometrically derived digital elevation data, we compute the terrain calibration factor and cosine of the local illumination angle. We then process and terrain-correct radar data sets acquired on April 16, 1994. In addition to the spectral data, we include surface slope to improve discrimination among several surface types. These data sets are then used in a decision tree to generate an image classification. This method is successful in identifying and mapping scree/talus, dry snow, dry snow-covered glacier, wet snow-covered glacier, and rock-covered glacier, as corroborated by comparison with existing surface cover maps and other ancillary information. Application of the classification scheme to data acquired on October 7 of the same year yields accurate results for most surface types but underreports the extent of dry snow cover.
","language":"English","publisher":"AGU","doi":"10.1029/98JE01893","issn":"01480227","usgsCitation":"Albright, T.P., Painter, T.H., Roberts, D.A., Shi, J., Dozier, J., and Fielding, E., 1998, Classification of surface types using SIR-C/X-SAR, Mount Everest Area, Tibet: Journal of Geophysical Research E: Planets, v. 103, no. E11, p. 25823-25833, https://doi.org/10.1029/98JE01893.","productDescription":"11 p.","startPage":"25823","endPage":"25833","numberOfPages":"11","costCenters":[{"id":222,"text":"Earth Resources Observation and Science (EROS) Center","active":true,"usgs":true}],"links":[{"id":479858,"rank":1,"type":{"id":40,"text":"Open Access Publisher Index Page"},"url":"https://doi.org/10.1029/98je01893","text":"Publisher Index Page"},{"id":231052,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"103","issue":"E11","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"5059f61de4b0c8380cd4c5d8","contributors":{"authors":[{"text":"Albright, Thomas P.","contributorId":78114,"corporation":false,"usgs":true,"family":"Albright","given":"Thomas","email":"","middleInitial":"P.","affiliations":[],"preferred":false,"id":385887,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Painter, Thomas H.","contributorId":12378,"corporation":false,"usgs":true,"family":"Painter","given":"Thomas","email":"","middleInitial":"H.","affiliations":[],"preferred":false,"id":385888,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Roberts, Dar A.","contributorId":100503,"corporation":false,"usgs":false,"family":"Roberts","given":"Dar","email":"","middleInitial":"A.","affiliations":[{"id":12804,"text":"Univ. of California Santa Barbara","active":true,"usgs":false}],"preferred":false,"id":385886,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Shi, Jiancheng","contributorId":11374,"corporation":false,"usgs":true,"family":"Shi","given":"Jiancheng","email":"","affiliations":[],"preferred":false,"id":385885,"contributorType":{"id":1,"text":"Authors"},"rank":4},{"text":"Dozier, Jeff","contributorId":190695,"corporation":false,"usgs":false,"family":"Dozier","given":"Jeff","email":"","affiliations":[],"preferred":false,"id":690387,"contributorType":{"id":1,"text":"Authors"},"rank":5},{"text":"Fielding, Eric","contributorId":50434,"corporation":false,"usgs":true,"family":"Fielding","given":"Eric","affiliations":[],"preferred":false,"id":690388,"contributorType":{"id":1,"text":"Authors"},"rank":6}]}} ,{"id":70020291,"text":"70020291 - 1998 - Radar attenuation tomography using the centroid frequency downshift method","interactions":[],"lastModifiedDate":"2019-10-15T09:56:30","indexId":"70020291","displayToPublicDate":"1998-01-01T00:00:00","publicationYear":"1998","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":2165,"text":"Journal of Applied Geophysics","active":true,"publicationSubtype":{"id":10}},"title":"Radar attenuation tomography using the centroid frequency downshift method","docAbstract":"A method for tomographically estimating electromagnetic (EM) wave attenuation based on analysis of centroid frequency downshift (CFDS) of impulse radar signals is described and applied to cross-hole radar data. The method is based on a constant-Q model, which assumes a linear frequency dependence of attenuation for EM wave propagation above the transition frequency. The method uses the CFDS to construct the projection function. In comparison with other methods for estimating attenuation, the CFDS method is relatively insensitive to the effects of geometric spreading, instrument response, and antenna coupling and radiation pattern, but requires the data to be broadband so that the frequency shift and variance can be easily measured. The method is well-suited for difference tomography experiments using electrically conductive tracers. The CFDS method was tested using cross-hole radar data collected at the U.S. Geological Survey Fractured Rock Research Site at Mirror Lake, New Hampshire (NH) during a saline-tracer injection experiment. The attenuation-difference tomogram created with the CFDS method outlines the spatial distribution of saline tracer within the tomography plane.
The 1994 spring phytoplankton bloom in South San Francisco Bay caused substantial reductions in concentrations of dissolved Cd, Ni, and Zn, but not Cu. We estimate that the equivalent of ~60% of the total annual input of Cd, Ni, and Zn from local waste‐water treatment plants is cycled through the phytoplankton in South Bay. The results suggest that processes that affect phytoplankton bloom frequency or intensity in estuaries (e.g. nutrient enrichment) may also affect metal trapping. The bloom was characterized by hydrographic surveys conducted at weekly intervals for 9 weeks. Metal samples were collected from the water column on three occasions, timed to bracket the period when the bloom was predicted. Factors that might confound observations of biological influences, such as freshwater inputs, were relatively constant during the study. Before the bloom, concentrations of dissolved Cd were 0.81 ± 0.02 nmol kg−1, Zn concentrations were 19.8 ± 1.5 nmol kg−1, Ni were 42 ± 1.4 nmol kg−1, and Cu were 37 ± 1.4 nmol kg−1. These values are elevated relative to riverine and coastal end‐members, reflecting inputs from wastewater and(or) sediments. At the height of the bloom, dissolved Zn, Cd, and Ni were reduced to 19, 50, and 75% of their prebloom concentrations, respectively. Dissolved Cu concentrations increased 20%. The mass of Cd taken up by phytoplankton was similar to the mass of Cd removed from solution if particle settling was considered, and Cd concentrations estimated in phytoplankton were higher than concentrations in suspended particulate material (SPM). Particulate concentrations of Zn and Ni during the bloom appeared to be dominated by the influence of changes in resuspension of Zn and Ni‐rich sediments.
In this paper we use numerical models of coupled biological-hydrodynamic processes to search for general principles of bloom regulation in estuarine waters. We address three questions: what are the dynamics of stratification in coastal systems as influenced by variable freshwater input and tidal stirring? How does phytoplankton growth respond to these dynamics? Can the classical Sverdrup Critical Depth Model (SCDM) be used to predict the timing of bloom events in shallow coastal domains such as estuaries? We present results of simulation experiments which assume that vertical transport and net phytoplankton growth rates are horizontally homogeneous. In the present approach the temporally and spatially varying turbulent diffusivities for various stratification scenarios are calculated using a hydrodynamic code that includes the Mellor-Yamada 2.5 turbulence closure model. These diffusivities are then used in a time- and depth-dependent advection-diffusion equation, incorporating sources and sinks, for the phytoplankton biomass. Our modeling results show that, whereas persistent stratification greatly increases the probability of a bloom, semidiurnal periodic stratification does not increase the likelihood of a phytoplankton bloom over that of a constantly unstratified water column. Thus, for phytoplankton blooms, the physical regime of periodic stratification is closer to complete mixing than to persistent stratification. Furthermore, the details of persistent stratification are important: surface layer depth, thickness of the pycnocline, vertical density difference, and tidal current speed all weigh heavily in producing conditions which promote the onset of phytoplankton blooms. Our model results for shallow tidal systems do not conform to the classical concepts of stratification and blooms in deep pelagic systems. First, earlier studies (Riley, 1942, for example) suggest a monotonic increase in surface layer production as the surface layer shallows. Our model results suggest, however, a nonmonotonic relationship between phytoplankton population growth and surface layer depth, which results from a balance between several 'competing' processes, including the interaction of sinking with turbulent mixing and average net growth occurring within the surface layer. Second, we show that the traditional SCDM must be refined for application to energetic shallow systems or for systems in which surface layer mixing is not strong enough to counteract the sinking loss of phytoplankton. This need for refinement arises because of the leakage of phytoplankton from the surface layer by turbulent diffusion and sinking, processes not considered in the classical SCDM. Our model shows that, even for low sinking rates and small turbulent diffusivities, a significant % of the phytoplankton biomass produced in the surface layer can be lost by these processes.
","language":"English","publisher":"Sears Foundation for Marine Research ","doi":"10.1357/002224098321822357","issn":"00222402","usgsCitation":"Lucas, L., Cloern, J., Koseff, J.R., Monismith, S., and Thompson, J., 1998, Does the Sverdrup critical depth model explain bloom dynamics in estuaries?: Journal of Marine Research, v. 56, no. 2, p. 375-415, https://doi.org/10.1357/002224098321822357.","productDescription":"41 p.","startPage":"375","endPage":"415","onlineOnly":"N","additionalOnlineFiles":"N","costCenters":[{"id":552,"text":"San Francisco Bay-Delta","active":false,"usgs":true},{"id":589,"text":"Toxic Substances Hydrology Program","active":true,"usgs":true},{"id":5079,"text":"Pacific Regional Director's Office","active":true,"usgs":true}],"links":[{"id":229951,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"56","issue":"2","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505a039ae4b0c8380cd50575","contributors":{"authors":[{"text":"Lucas, L.V.","contributorId":62777,"corporation":false,"usgs":true,"family":"Lucas","given":"L.V.","email":"","affiliations":[],"preferred":false,"id":389608,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Cloern, J. E.","contributorId":59453,"corporation":false,"usgs":true,"family":"Cloern","given":"J. E.","affiliations":[],"preferred":false,"id":389607,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Koseff, Jeffrey R.","contributorId":37915,"corporation":false,"usgs":false,"family":"Koseff","given":"Jeffrey","email":"","middleInitial":"R.","affiliations":[{"id":6986,"text":"Stanford University","active":true,"usgs":false}],"preferred":false,"id":389605,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Monismith, Stephen G.","contributorId":57228,"corporation":false,"usgs":true,"family":"Monismith","given":"Stephen G.","affiliations":[],"preferred":false,"id":389606,"contributorType":{"id":1,"text":"Authors"},"rank":4},{"text":"Thompson, J.K.","contributorId":103300,"corporation":false,"usgs":true,"family":"Thompson","given":"J.K.","email":"","affiliations":[],"preferred":false,"id":389609,"contributorType":{"id":1,"text":"Authors"},"rank":5}]}} ,{"id":70020838,"text":"70020838 - 1998 - Strain IMB-1, a novel bacterium for the removal of methyl bromide in fumigated agricultural soils","interactions":[],"lastModifiedDate":"2023-01-12T20:43:36.481289","indexId":"70020838","displayToPublicDate":"1998-01-01T00:00:00","publicationYear":"1998","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":850,"text":"Applied and Environmental Microbiology","active":true,"publicationSubtype":{"id":10}},"title":"Strain IMB-1, a novel bacterium for the removal of methyl bromide in fumigated agricultural soils","docAbstract":"A facultatively methylotrophic bacterium, strain IMB-1, that has been isolated from agricultural soil grows on methyl bromide (MeBr), methyl iodide, methyl chloride, and methylated amines, as well as on glucose, pyruvate, or acetate. Phylogenetic analysis of its 16S rRNA gene sequence indicates that strain IMB-1 classes in the alpha subgroup of the class Proteobacteria and is closely related to members of the genus Rhizobium. The ability of strain IMB-1 to oxidize MeBr to CO2 is constitutive in cells regardless of the growth substrate. Addition of cell suspensions of strain IMB-1 to soils greatly accelerates the oxidation of MeBr, as does pretreatment of soils with low concentrations of methyl iodide. These results suggest that soil treatment strategies can be devised whereby bacteria can effectively consume MeBr during field fumigations, which would diminish or eliminate the outward flux of MeBr to the atmosphere.
","language":"English","publisher":"American Society for Microbiology","doi":"10.1128/AEM.64.8.2899-2905.1998","issn":"00992240","usgsCitation":"Connell, H.T., Costello, A., Lidstrom, M., and Oremland, R., 1998, Strain IMB-1, a novel bacterium for the removal of methyl bromide in fumigated agricultural soils: Applied and Environmental Microbiology, v. 64, no. 8, p. 2899-2905, https://doi.org/10.1128/AEM.64.8.2899-2905.1998.","productDescription":"7 p.","startPage":"2899","endPage":"2905","costCenters":[{"id":589,"text":"Toxic Substances Hydrology Program","active":true,"usgs":true}],"links":[{"id":479733,"rank":2,"type":{"id":40,"text":"Open Access Publisher Index Page"},"url":"https://doi.org/10.1128/aem.64.8.2899-2905.1998","text":"Publisher Index Page"},{"id":229835,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"64","issue":"8","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505b988ee4b08c986b31c093","contributors":{"authors":[{"text":"Connell, Hancock T.L.","contributorId":9418,"corporation":false,"usgs":true,"family":"Connell","given":"Hancock","email":"","middleInitial":"T.L.","affiliations":[],"preferred":false,"id":387712,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Costello, A.M.","contributorId":49951,"corporation":false,"usgs":true,"family":"Costello","given":"A.M.","email":"","affiliations":[],"preferred":false,"id":387713,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Lidstrom, M.E.","contributorId":93207,"corporation":false,"usgs":true,"family":"Lidstrom","given":"M.E.","email":"","affiliations":[],"preferred":false,"id":387714,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Oremland, R.S.","contributorId":97512,"corporation":false,"usgs":true,"family":"Oremland","given":"R.S.","email":"","affiliations":[],"preferred":false,"id":387715,"contributorType":{"id":1,"text":"Authors"},"rank":4}]}} ,{"id":70020161,"text":"70020161 - 1998 - Application of the surface complexation concept to complex mineral assemblages","interactions":[],"lastModifiedDate":"2019-02-01T06:20:28","indexId":"70020161","displayToPublicDate":"1998-01-01T00:00:00","publicationYear":"1998","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1565,"text":"Environmental Science & Technology","onlineIssn":"1520-5851","printIssn":"0013-936X","active":true,"publicationSubtype":{"id":10}},"title":"Application of the surface complexation concept to complex mineral assemblages","docAbstract":"Two types of modeling approaches are illustrated for describing inorganic contaminant adsorption in aqueous environments: (a) the component additivity approach and (b) the generalized composite approach. Each approach is applied to simulate Zn2+ adsorption by a well-characterized sediment collected from an aquifer at Cape Cod, MA. Zn2+ adsorption by the sediment was studied in laboratory batch experiments with a range of pH and Zn(II) concentrations selected to encompass conditions observed in the aquifer. In the generalized composite approach, one, and two-site surface complexation model parameters were calibrated with the experimental data using FITEQL. The pH dependence of Zn2+ adsorption was simulated without explicit representation of electrostatic energy terms. Surface acidity constants and ion pair formation by major electrolyte ions were also not required in the model thereby minimizing the number of fitted parameters. Predictions of Zn2+ adsorption with the component additivity modeling approach did not simulate the experimental data adequately without manipulation of surface area or site density parameter values. To apply the component additivity approach to environmental sorbents, further research is needed to better characterize the composition of sediment surface coatings. The generalized composite modeling approach requires less information and can be viewed as more practical for application within solute transport models. With only three adjustable parameters, this approach could simulate Zn2+ adsorption over a range of chemical conditions that would cause several orders of magnitude variation in the distribution coefficient (K(d)) for Zn2+ within the aquifer.Two types of modeling approaches are illustrated for describing inorganic contaminant adsorption in aqueous environments: (a) the component additivity approach and (b) the generalized composite approach. Each approach is applied to simulate Zn2+ adsorption by a well-characterized sediment collected from an aquifer at Cape Cod, MA. Zn2+ adsorption by the sediment was studied in laboratory batch experiments with a range of pH and Zn(II) concentrations selected to encompass conditions observed in the aquifer. In the generalized composite approach, one- and two-site surface complexation model parameters were calibrated with the experimental data using FITEQL. The pH dependence of Zn2+ adsorption was simulated without explicit representation of electrostatic energy terms. Surface acidity constants and ion pair formation by major electrolyte ions were also not required in the model, thereby minimizing the number of fitted parameters. Predictions of Zn2+ adsorption with the component additivity modeling approach did not simulate the experimental data adequately without manipulation of surface area or site density parameter values. To apply the component additivity approach to environmental sorbents, further research is needed to better characterize the composition of sediment surface coatings. The generalized composite modeling approach requires less information and can be viewed as more practical for application within solute transport models. With only three adjustable parameters, this approach could simulate Zn2+ adsorption over a range of chemical conditions that would cause several orders of magnitude variation in the distribution coefficient (Kd) for Zn2+ within the aquifer.","language":"English","publisher":"ACS","doi":"10.1021/es980312q","issn":"0013936X","usgsCitation":"Davis, J., Coston, J., Kent, D., and Fuller, C.C., 1998, Application of the surface complexation concept to complex mineral assemblages: Environmental Science & Technology, v. 32, no. 19, p. 2820-2828, https://doi.org/10.1021/es980312q.","productDescription":"9 p.","startPage":"2820","endPage":"2828","costCenters":[{"id":589,"text":"Toxic Substances Hydrology Program","active":true,"usgs":true}],"links":[{"id":227709,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"},{"id":205970,"rank":9999,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.1021/es980312q"}],"volume":"32","issue":"19","noUsgsAuthors":false,"publicationDate":"1998-08-21","publicationStatus":"PW","scienceBaseUri":"5059ecbae4b0c8380cd49452","contributors":{"authors":[{"text":"Davis, J.A.","contributorId":71694,"corporation":false,"usgs":true,"family":"Davis","given":"J.A.","email":"","affiliations":[],"preferred":false,"id":385245,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Coston, J.A.","contributorId":59572,"corporation":false,"usgs":true,"family":"Coston","given":"J.A.","email":"","affiliations":[],"preferred":false,"id":385244,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Kent, D.B.","contributorId":16588,"corporation":false,"usgs":true,"family":"Kent","given":"D.B.","email":"","affiliations":[],"preferred":false,"id":385242,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Fuller, C. C.","contributorId":29858,"corporation":false,"usgs":true,"family":"Fuller","given":"C.","email":"","middleInitial":"C.","affiliations":[],"preferred":false,"id":385243,"contributorType":{"id":1,"text":"Authors"},"rank":4}]}} ,{"id":70020152,"text":"70020152 - 1998 - Molybdate transport in a chemically complex aquifer: Field measurements compared with solute-transport model predictions","interactions":[],"lastModifiedDate":"2019-02-04T07:48:45","indexId":"70020152","displayToPublicDate":"1998-01-01T00:00:00","publicationYear":"1998","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":3722,"text":"Water Resources Research","onlineIssn":"1944-7973","printIssn":"0043-1397","active":true,"publicationSubtype":{"id":10}},"title":"Molybdate transport in a chemically complex aquifer: Field measurements compared with solute-transport model predictions","docAbstract":"A natural-gradient tracer test was conducted in an unconfined sand and gravel aquifer on Cape Cod, Massachusetts. Molybdate was included in the injectate to study the effects of variable groundwater chemistry on its aqueous distribution and to evaluate the reliability of laboratory experiments for identifying and quantifying reactions that control the transport of reactive solutes in groundwater. Transport of molybdate in this aquifer was controlled by adsorption. The amount adsorbed varied with aqueous chemistry that changed with depth as freshwater recharge mixed with a plume of sewage-contaminated groundwater. Molybdate adsorption was strongest near the water table where pH (5.7) and the concentration of the competing solutes phosphate (2.3 micromolar) and sulfate (86 micromolar) were low. Adsorption of molybdate decreased with depth as pH increased to 6.5, phosphate increased to 40 micromolar, and sulfate increased to 340 micromolar. A one-site diffuse-layer surface-complexation model and a two-site diffuse-layer surface-complexation model were used to simulate adsorption. Reactions and equilibrium constants for both models were determined in laboratory experiments and used in the reactive-transport model PHAST to simulate the two-dimensional transport of molybdate during the tracer test. No geochemical parameters were adjusted in the simulation to improve the fit between model and field data. Both models simulated the travel distance of the molybdate cloud to within 10% during the 2-year tracer test; however, the two-site diffuse-layer model more accurately simulated the molybdate concentration distribution within the cloud.
","language":"English","publisher":"American Geophysical Union","doi":"10.1029/98WR02163","usgsCitation":"Stollenwerk, K.G., 1998, Molybdate transport in a chemically complex aquifer: Field measurements compared with solute-transport model predictions: Water Resources Research, v. 34, no. 10, p. 2727-2740, https://doi.org/10.1029/98WR02163.","productDescription":"14 p.","startPage":"2727","endPage":"2740","costCenters":[{"id":589,"text":"Toxic Substances Hydrology Program","active":true,"usgs":true}],"links":[{"id":228233,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"country":"United States","state":"Massachusetts","otherGeospatial":"Cape Cod","volume":"34","issue":"10","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505a5d27e4b0c8380cd701c3","contributors":{"authors":[{"text":"Stollenwerk, Kenneth G. kgstolle@usgs.gov","contributorId":578,"corporation":false,"usgs":true,"family":"Stollenwerk","given":"Kenneth","email":"kgstolle@usgs.gov","middleInitial":"G.","affiliations":[],"preferred":true,"id":385214,"contributorType":{"id":1,"text":"Authors"},"rank":1}]}} ,{"id":70020116,"text":"70020116 - 1998 - The role of near-stream riparian zones in the hydrology of steep upland catchments","interactions":[],"lastModifiedDate":"2012-03-12T17:19:16","indexId":"70020116","displayToPublicDate":"1998-01-01T00:00:00","publicationYear":"1998","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1934,"text":"IAHS-AISH Publication","active":true,"publicationSubtype":{"id":10}},"title":"The role of near-stream riparian zones in the hydrology of steep upland catchments","docAbstract":"Surface and subsurface waters were monitored and sampled at various topographic positions in a 40.5-ha headwater catchment to test several hypotheses of runoff generation and stream chemical and isotopic evolution during snowmelt. Transmissivity feedback was observed on the hillslopes during the melt period. Groundwater levels and stream DOC were highly correlated with stream discharge. Hysteresis in the groundwater-streamflow relation suggests that localized water flux from the riparian areas controlled the rising limb and main peak response of the melt hydrograph, whilst hillslope drainage controlled the timing and volume of the falling limb. Lateral flow from upslope positions was detected in the riparian zone.","largerWorkType":{"id":2,"text":"Article"},"largerWorkTitle":"IAHS-AISH Publication","largerWorkSubtype":{"id":10,"text":"Journal Article"},"language":"English","issn":"01447815","usgsCitation":"McDonnell, J.J., McGlynn, B., Kendall, K., Shanley, J., and Kendall, C., 1998, The role of near-stream riparian zones in the hydrology of steep upland catchments: IAHS-AISH Publication, v. 248, p. 173-180.","startPage":"173","endPage":"180","numberOfPages":"8","costCenters":[],"links":[{"id":228274,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"248","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505baf89e4b08c986b324889","contributors":{"authors":[{"text":"McDonnell, Jeffery J. 0000-0002-3880-3162","orcid":"https://orcid.org/0000-0002-3880-3162","contributorId":62723,"corporation":false,"usgs":false,"family":"McDonnell","given":"Jeffery","email":"","middleInitial":"J.","affiliations":[],"preferred":false,"id":385097,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"McGlynn, B.L.","contributorId":106664,"corporation":false,"usgs":true,"family":"McGlynn","given":"B.L.","email":"","affiliations":[],"preferred":false,"id":385099,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Kendall, K.","contributorId":88507,"corporation":false,"usgs":true,"family":"Kendall","given":"K.","affiliations":[],"preferred":false,"id":385098,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Shanley, J.","contributorId":37488,"corporation":false,"usgs":true,"family":"Shanley","given":"J.","affiliations":[],"preferred":false,"id":385096,"contributorType":{"id":1,"text":"Authors"},"rank":4},{"text":"Kendall, C. 0000-0002-0247-3405","orcid":"https://orcid.org/0000-0002-0247-3405","contributorId":35050,"corporation":false,"usgs":true,"family":"Kendall","given":"C.","affiliations":[],"preferred":false,"id":385095,"contributorType":{"id":1,"text":"Authors"},"rank":5}]}} ,{"id":70021295,"text":"70021295 - 1998 - A mini drivepoint sampler for measuring pore water solute concentrations in the hyporheic zone of sand-bottom streams","interactions":[],"lastModifiedDate":"2020-01-06T06:20:36","indexId":"70021295","displayToPublicDate":"1998-01-01T00:00:00","publicationYear":"1998","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":2620,"text":"Limnology and Oceanography","active":true,"publicationSubtype":{"id":10}},"title":"A mini drivepoint sampler for measuring pore water solute concentrations in the hyporheic zone of sand-bottom streams","docAbstract":"A new method for collecting pore-water samples in sand and gravel streambeds is presented. We developed a mini drivepoint solution sampling (MINIPOINT) technique to collect pore-water samples at 2.5-cm vertical resolution. The sampler consisted of six small-diameter stainless steel drivepoints arranged in a 10-cm-diameter circular array. In a simple procedure, the sampler was installed in the streambed to preset drivepoint depths of 2.5, 5.0, 7.5, 10.0, 12.5, and 15.0 cm. Sampler performance was evaluated in the Shingobee River, Minnesota, and Pinal Creek, Arizona, by measuring the vertical gradient of chloride concentration in pore water beneath the streambed that was established by the uninterrupted injection to the stream for 3 d. Pore-water samples were withdrawn from all drivepoints simultaneously. In the first evaluation, the vertical chloride gradient was unchanged at withdrawal rates between 0.3 and 4.0 ml min-1 but was disturbed at higher rates. In the second evaluation, up to 70 ml of pore water was withdrawn from each drivepoint at a withdrawal rate of 2.5 ml min-1 without disturbing the vertical chloride gradient. Background concentrations of other solutes were also determined with MINIPOINT sampling. Steep vertical gradients were present for biologically reactive solutes such as DO, NH4/+, NO3/-, and dissolved organic C in the top 20 cm of the streambed. These detailed solute profiles in the hyporheic zone could not have been determined without a method for close interval vertical sampling that does not disturb natural hydrologic mixing between stream water and groundwater.","language":"English","publisher":"Wiley","issn":"00243590","usgsCitation":"Duff, J.H., Murphy, F., Fuller, C.C., Triska, F., Harvey, J.W., and Jackman, A.P., 1998, A mini drivepoint sampler for measuring pore water solute concentrations in the hyporheic zone of sand-bottom streams: Limnology and Oceanography, v. 43, no. 6, p. 1378-1383.","productDescription":"6 p.","startPage":"1378","endPage":"1383","numberOfPages":"6","costCenters":[{"id":589,"text":"Toxic Substances Hydrology Program","active":true,"usgs":true}],"links":[{"id":230103,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"43","issue":"6","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"5059e467e4b0c8380cd4662f","contributors":{"authors":[{"text":"Duff, John H. jhduff@usgs.gov","contributorId":961,"corporation":false,"usgs":true,"family":"Duff","given":"John","email":"jhduff@usgs.gov","middleInitial":"H.","affiliations":[{"id":438,"text":"National Research Program - Western Branch","active":true,"usgs":true},{"id":154,"text":"California Water Science Center","active":true,"usgs":true}],"preferred":true,"id":778900,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Murphy, Fred 0000-0001-6147-7564 fmurphy@usgs.gov","orcid":"https://orcid.org/0000-0001-6147-7564","contributorId":209970,"corporation":false,"usgs":true,"family":"Murphy","given":"Fred","email":"fmurphy@usgs.gov","affiliations":[{"id":617,"text":"Volcano Science Center","active":true,"usgs":true}],"preferred":true,"id":778901,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Fuller, Christopher C. 0000-0002-2354-8074 ccfuller@usgs.gov","orcid":"https://orcid.org/0000-0002-2354-8074","contributorId":1831,"corporation":false,"usgs":true,"family":"Fuller","given":"Christopher","email":"ccfuller@usgs.gov","middleInitial":"C.","affiliations":[{"id":37277,"text":"WMA - Earth System Processes Division","active":true,"usgs":true},{"id":374,"text":"Maryland Water Science Center","active":true,"usgs":true},{"id":36183,"text":"Hydro-Ecological Interactions Branch","active":true,"usgs":true},{"id":438,"text":"National Research Program - Western Branch","active":true,"usgs":true}],"preferred":true,"id":778902,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Triska, F.","contributorId":70173,"corporation":false,"usgs":true,"family":"Triska","given":"F.","email":"","affiliations":[],"preferred":false,"id":778903,"contributorType":{"id":1,"text":"Authors"},"rank":4},{"text":"Harvey, Judson W. 0000-0002-2654-9873 jwharvey@usgs.gov","orcid":"https://orcid.org/0000-0002-2654-9873","contributorId":1796,"corporation":false,"usgs":true,"family":"Harvey","given":"Judson","email":"jwharvey@usgs.gov","middleInitial":"W.","affiliations":[{"id":436,"text":"National Research Program - Eastern Branch","active":true,"usgs":true}],"preferred":true,"id":778904,"contributorType":{"id":1,"text":"Authors"},"rank":5},{"text":"Jackman, Alan P.","contributorId":28239,"corporation":false,"usgs":true,"family":"Jackman","given":"Alan","email":"","middleInitial":"P.","affiliations":[],"preferred":false,"id":778905,"contributorType":{"id":1,"text":"Authors"},"rank":6}]}} ,{"id":70020069,"text":"70020069 - 1998 - Uptake and loss kinetics of Cd, Cr and Zn in the bivalves Potamocorbula amurensis and Macoma balthica: Effects of size and salinity","interactions":[],"lastModifiedDate":"2019-01-30T09:04:02","indexId":"70020069","displayToPublicDate":"1998-01-01T00:00:00","publicationYear":"1998","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":2663,"text":"Marine Ecology Progress Series","active":true,"publicationSubtype":{"id":10}},"title":"Uptake and loss kinetics of Cd, Cr and Zn in the bivalves Potamocorbula amurensis and Macoma balthica: Effects of size and salinity","docAbstract":"Methylmercury (MeHg) degradation was investigated along an eutrophication gradient in the Florida Everglades by quantifying 14CH4 and 14CO2 production after incubation of anaerobic sediments with [14C]MeHg. Degradation rate constants (k) were consistently ≤0.1 d-1 and decreased with sediment depth. Higher k values were observed when shorter incubation times and lower MeHg amendment levels were used, and k increased 2-fold as in-situ MeHg concentrations were approached. The average floc layer k was 0.046 ± 0.023 d-1 (n = 17) for 1−2 day incubations. In-situ degradation rates were estimated to be 0.02−0.5 ng of MeHg (g of dry sediment)-1 d-1, increasing from eutrophied to pristine areas. Nitrate-respiring bacteria did not demethylate MeHg, and NO3- addition partially inhibited degradation in some cases. MeHg degradation rates were not affected by PO43- addition. 14CO2 production in all samples indicated that oxidative demethylation (OD) was an important degradation mechanism. OD occurred over 5 orders of magnitude of applied MeHg concentration, with lowest limits [1−18 ng of MeHg (g of dry sediment)-1] in the range of in-situ MeHg levels. Sulfate reducers and methanogens were the primary agents of anaerobic OD, although it is suggested that methanogens dominate degradation at in-situ MeHg concentrations. Specific pathways of OD by these two microbial groups are proposed.
Groundwater and stream water data collected at three headwater catchments in the Neversink River watershed indicate that base flow is sustained by groundwater from two sources: a shallow flow system within the till and soil and a deep flow system within bedrock fractures and bedding planes that discharges as perennial springs. Data from eight wells finished near the till/bedrock interface indicate that saturated conditions are not maintained in the shallow flow system during most summers. In contrast, the discharge of a perennial spring remained constant during two summer rainstorms, providing evidence that the deep flow system is disconnected from the shallow flow system in summer. Discharge from perennial springs was the principal source of streamflow in a headwater reach during low flow. Mean NO3− concentrations were 20–25 μmol L−1 in five perennial springs during the summer but only 5–10 μmol L−1 in shallow groundwater. Thus the deep flow system does not reflect typical NO3− concentrations in the soil during summer. A hydrologic budget at a headwater drainage reveals that March and late fall are the principal groundwater recharge periods. Residence time modeling based on analyses of 18O and 35S indicates that groundwater in the deep flow system is 6–22 months old. These data indicate that summer base flow largely originates from previous dormant seasons when available soil NO3− is greater. In these Catskill watersheds, high base flow concentrations of NO3− during summer do not provide sufficient evidence that the atmospheric N deposition rate exceeds the demand of terrestrial vegetation.
","language":"English","publisher":"American Geophysical Union","doi":"10.1029/98WR01282","usgsCitation":"Burns, D.A., Murdoch, P.S., Lawrence, G.B., and Michel, R.L., 1998, Effect of groundwater springs on NO3− concentrations during summer in Catskill Mountain streams: Water Resources Research, v. 34, no. 8, p. 1987-1996, https://doi.org/10.1029/98WR01282.","productDescription":"10 p.","startPage":"1987","endPage":"1996","costCenters":[],"links":[{"id":487361,"rank":1,"type":{"id":40,"text":"Open Access Publisher Index Page"},"url":"https://doi.org/10.1029/98wr01282","text":"Publisher Index Page"},{"id":230195,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"country":"United States","volume":"34","issue":"8","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505a05e6e4b0c8380cd50ff8","contributors":{"authors":[{"text":"Burns, Douglas A. 0000-0001-6516-2869 daburns@usgs.gov","orcid":"https://orcid.org/0000-0001-6516-2869","contributorId":1237,"corporation":false,"usgs":true,"family":"Burns","given":"Douglas","email":"daburns@usgs.gov","middleInitial":"A.","affiliations":[{"id":474,"text":"New York Water Science Center","active":true,"usgs":true}],"preferred":true,"id":387650,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Murdoch, Peter S. 0000-0001-9243-505X pmurdoch@usgs.gov","orcid":"https://orcid.org/0000-0001-9243-505X","contributorId":2453,"corporation":false,"usgs":true,"family":"Murdoch","given":"Peter","email":"pmurdoch@usgs.gov","middleInitial":"S.","affiliations":[{"id":5067,"text":"Northeast Regional Director's Office","active":true,"usgs":true}],"preferred":true,"id":387651,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Lawrence, Gregory B. 0000-0002-8035-2350 glawrenc@usgs.gov","orcid":"https://orcid.org/0000-0002-8035-2350","contributorId":867,"corporation":false,"usgs":true,"family":"Lawrence","given":"Gregory","email":"glawrenc@usgs.gov","middleInitial":"B.","affiliations":[{"id":474,"text":"New York Water Science Center","active":true,"usgs":true}],"preferred":true,"id":387652,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Michel, Robert L. rlmichel@usgs.gov","contributorId":823,"corporation":false,"usgs":true,"family":"Michel","given":"Robert","email":"rlmichel@usgs.gov","middleInitial":"L.","affiliations":[{"id":148,"text":"Branch of Regional Research-Western Region","active":false,"usgs":true}],"preferred":true,"id":387653,"contributorType":{"id":1,"text":"Authors"},"rank":4}]}} ,{"id":70020790,"text":"70020790 - 1998 - Trace fossil analysis of lacustrine facies and basins","interactions":[],"lastModifiedDate":"2012-03-12T17:19:43","indexId":"70020790","displayToPublicDate":"1998-01-01T00:00:00","publicationYear":"1998","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":2996,"text":"Palaeogeography, Palaeoclimatology, Palaeoecology","printIssn":"0031-0182","active":true,"publicationSubtype":{"id":10}},"title":"Trace fossil analysis of lacustrine facies and basins","docAbstract":"Two ichnofacies are typical of lacustrine depositional systems. The Scoyenia ichnofacies characterizes transitional terrestrial/nonmarine aquatic substrates, periodically inundated or desiccated, and therefore is commonly present in lake margin facies. The Mermia ichnofacies is associated with well oxygenated, permanent subaqueous, fine-grained substrates of hydrologically open, perennial lakes. Bathymetric zonations within the Mermia ichnofacies are complicated by the wide variability of lacustrine systems. Detected proximal-distal trends are useful within particular lake basins, but commonly difficult to extrapolate to other lakes. Other potential ichnofacies include the typically marine Skolithos ichnofacies for high-energy zones of lakes and substrate-controlled, still unnamed ichnofacies, associated to lake margin deposits. Trace fossils are useful for sedimentologic analysis of event beds. Lacustrine turbidites are characterized by low-diversity suites, reflecting colonization by opportunistic organisms after the turbidite event. Underflow current beds record animal activity contemporaneous with nearly continuous sedimentation. Ichnologic studies may also help to distinguish between marine and lacustrine turbidites. Deep-marine turbidites host the Nereites ichnofacies that consists of high diversity of ornate grazing traces and graphoglyptids, recording highly specialized feeding strategies developed to solve the problem of the scarcity of food in the deep sea. Deep lacustrine environments contain the Mermia ichnofacies, which is dominated by unspecialized grazing and feeding traces probably related to the abundance and accessibility of food in lacustrine systems. The lower diversity of lacustrine ichnofaunas in comparison with deep-sea assemblages more likely reflects lower species diversity as a consequence of less stable conditions. Increase of depth and extent of bioturbation through geologic time produced a clear signature in the ichnofabric record of lacustrine facies. Paleozoic lacustrine ichnofaunas are typically dominated by surface trails with little associated bioturbation. During the Mesozoic, bioturbation depth was higher in lake margin facies than in fully lacustrine deposits. While significant degrees of bioturbation were attained in lake margin facies during the Triassic, major biogenic disruption of primary bedding in subaqueous lacustrine deposits did not occur until the Cretaceous.","largerWorkType":{"id":2,"text":"Article"},"largerWorkTitle":"Palaeogeography, Palaeoclimatology, Palaeoecology","largerWorkSubtype":{"id":10,"text":"Journal Article"},"language":"English","doi":"10.1016/S0031-0182(98)00020-0","issn":"00310182","usgsCitation":"Buatois, L., and Mangano, M., 1998, Trace fossil analysis of lacustrine facies and basins: Palaeogeography, Palaeoclimatology, Palaeoecology, v. 140, no. 1-4, p. 367-382, https://doi.org/10.1016/S0031-0182(98)00020-0.","startPage":"367","endPage":"382","numberOfPages":"16","costCenters":[],"links":[{"id":206851,"rank":9999,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.1016/S0031-0182(98)00020-0"},{"id":230964,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"140","issue":"1-4","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505bb665e4b08c986b326c39","contributors":{"authors":[{"text":"Buatois, L.A.","contributorId":40740,"corporation":false,"usgs":true,"family":"Buatois","given":"L.A.","affiliations":[],"preferred":false,"id":387537,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Mangano, M.G.","contributorId":7432,"corporation":false,"usgs":true,"family":"Mangano","given":"M.G.","email":"","affiliations":[],"preferred":false,"id":387536,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":70020760,"text":"70020760 - 1998 - Benthic sulfate reduction along the Chesapeake Bay central channel. I. Spatial trends and controls","interactions":[],"lastModifiedDate":"2019-02-04T09:28:04","indexId":"70020760","displayToPublicDate":"1998-01-01T00:00:00","publicationYear":"1998","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":2663,"text":"Marine Ecology Progress Series","active":true,"publicationSubtype":{"id":10}},"title":"Benthic sulfate reduction along the Chesapeake Bay central channel. I. Spatial trends and controls","docAbstract":"Factors controlling the spatial distribution of benthic sulfate reduction (SR) were investigated at 3 stations [upper (UB), mid (MB) and lower bay (LB)] along the Chesapeake Bay (eastern USA) central channel from early spring through late fall, 1989 to 1994. Annual rates of 0 to 12 cm depth-integrated SR were 0.96, 9.62 and 6.33 mol S m-2 yr-1 for UB, MB and LB, respectively, as calculated from 35SO42- incubations. SR was carbon limited at UB, LB, and at the sediment surface at MB, and SO42- limited at depth at MB. Temperature explained 33 to 68% of the variability in annual rates, with an apparent influence on SR which increased in the seaward direction in surface sediments. We speculate that the enhanced response of SR to temperature in LB surface sediments was linked to seasonal variations in macrofaunal activity associated with temperature. Estimates of reduced-S burial indicated that only 4 to 8% of sulfur reduced annually was buried as Fe-S minerals at MB and LB, with the remainder presumably being reoxidized. In contrast, >50% of the sulfur reduced annually was buried at UB, due to comparatively low SR rates and the high concentration of reactive iron in the oligohaline region. SR mineralized 18 to 32% of the annual primary production. Our results indicate that organic quality may be more important than the absolute quantity of organic loading in dictating the magnitude of benthic SR rates along an estuarine gradient. Spatial trends in SR reflected the combined influence of deposited organic matter quality and quantity, SO42- availability, the presence or absence of benthic macrofauna, overlying water dissolved O2 conditions, reduced-S reoxidation dynamics, and iron-sulfide mineral formation.","language":"English","publisher":"Inter-Research","doi":"10.3354/meps168213","issn":"01718630","usgsCitation":"Marvin-DiPasquale, M., and Capone, D., 1998, Benthic sulfate reduction along the Chesapeake Bay central channel. I. Spatial trends and controls: Marine Ecology Progress Series, v. 168, p. 213-228, https://doi.org/10.3354/meps168213.","productDescription":"16 p.","startPage":"213","endPage":"228","costCenters":[{"id":589,"text":"Toxic Substances Hydrology Program","active":true,"usgs":true}],"links":[{"id":479853,"rank":1,"type":{"id":40,"text":"Open Access Publisher Index Page"},"url":"https://doi.org/10.3354/meps168213","text":"Publisher Index Page"},{"id":231080,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"},{"id":266005,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.3354/meps168213"}],"volume":"168","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"5059f0c2e4b0c8380cd4a8d1","contributors":{"authors":[{"text":"Marvin-DiPasquale, M. C.","contributorId":6605,"corporation":false,"usgs":true,"family":"Marvin-DiPasquale","given":"M. C.","affiliations":[],"preferred":false,"id":387392,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Capone, D.G.","contributorId":105876,"corporation":false,"usgs":true,"family":"Capone","given":"D.G.","email":"","affiliations":[],"preferred":false,"id":387393,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":70194884,"text":"70194884 - 1998 - Hydrogeologic studies at the USGS Amargosa Desert Research Site","interactions":[],"lastModifiedDate":"2018-09-10T09:15:14","indexId":"70194884","displayToPublicDate":"1998-01-01T00:00:00","publicationYear":"1998","noYear":false,"publicationType":{"id":5,"text":"Book chapter"},"publicationSubtype":{"id":24,"text":"Book Chapter"},"seriesTitle":{"id":5607,"text":"Friends of the Pleistocene Field Trip Guide","active":true,"publicationSubtype":{"id":24}},"title":"Hydrogeologic studies at the USGS Amargosa Desert Research Site","docAbstract":"In 1976, the U.S. Geological Survey (USGS) began studies of unsaturated-zone hydrology in the Amargosa Desert in support of the USGS Low-Level Radioactive Waste Program. In 1983, agreements with the Bureau of Land Management and the State of Nevada established two field study areas: a 16-ha area adjacent to a waste-burial facility 17 km south of Beatty and a 0.1-ha area about 3 km farther south (fig. 1A). The study areas are collectively known as the Amargosa Desert Research Site (ADRS). Investigations at the ADRS have provided long-term benchmark information about hydraulic characteristics and soil-water movement for undisturbed conditions and for simulated waste-site conditions in arid environments. In 1995, as a result of unexpectedly finding high concentrations of tritium and carbon-14 in the unsaturated zone beneath the ADRS, the scope of research was broadened to include the study of processes affecting radionuclide transport. The ADRS was incorporated into the USGS Toxic Substances Hydrology Program in 1997. Research at the site is a multidisciplinary, collaborative effort that involves scientists from the USGS, universities, research institutes, and national laboratories. The overall objective for research at the site is to improve understanding of and methods for characterizing mechanisms that control subsurface migration and fate of contaminants in arid environments.
","largerWorkType":{"id":4,"text":"Book"},"largerWorkTitle":"Quaternary geology of the Yucca Mountain area, southern Nevada: Field trip guide","largerWorkSubtype":{"id":15,"text":"Monograph"},"conferenceTitle":"1998 Annual Meeting of the Friends of the Pleistocene, Pacific Cell","conferenceDate":"October 9-11, 1998","language":"English","publisher":"Friends of the Pleistocene, Pacific Cell","usgsCitation":"Andraski, B.J., and Stonestrom, D.A., 1998, Hydrogeologic studies at the USGS Amargosa Desert Research Site, chap. of Quaternary geology of the Yucca Mountain area, southern Nevada: Field trip guide: Friends of the Pleistocene Field Trip Guide, p. 210-216.","productDescription":"7 p.","startPage":"210","endPage":"216","costCenters":[{"id":465,"text":"Nevada Water Science Center","active":true,"usgs":true},{"id":589,"text":"Toxic Substances Hydrology Program","active":true,"usgs":true}],"links":[{"id":350656,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"},{"id":350655,"rank":1,"type":{"id":15,"text":"Index Page"},"url":"https://www.fop.cascadiageo.org/?page_id=629"}],"country":"United States","state":"Nevada","otherGeospatial":"Amargosa Desert Research Site","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"5a6c4c9ee4b06e28e9cabb38","contributors":{"editors":[{"text":"Taylor, Emily M. 0000-0003-1152-5761 emtaylor@usgs.gov","orcid":"https://orcid.org/0000-0003-1152-5761","contributorId":1240,"corporation":false,"usgs":true,"family":"Taylor","given":"Emily","email":"emtaylor@usgs.gov","middleInitial":"M.","affiliations":[{"id":318,"text":"Geosciences and Environmental Change Science Center","active":true,"usgs":true}],"preferred":false,"id":725901,"contributorType":{"id":2,"text":"Editors"},"rank":1}],"authors":[{"text":"Andraski, Brian J. 0000-0002-2086-0417 andraski@usgs.gov","orcid":"https://orcid.org/0000-0002-2086-0417","contributorId":168800,"corporation":false,"usgs":true,"family":"Andraski","given":"Brian","email":"andraski@usgs.gov","middleInitial":"J.","affiliations":[{"id":38175,"text":"Toxics Substances Hydrology Program","active":true,"usgs":true},{"id":465,"text":"Nevada Water Science Center","active":true,"usgs":true},{"id":438,"text":"National Research Program - Western Branch","active":true,"usgs":true}],"preferred":false,"id":725899,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Stonestrom, David A. 0000-0001-7883-3385 dastones@usgs.gov","orcid":"https://orcid.org/0000-0001-7883-3385","contributorId":2280,"corporation":false,"usgs":true,"family":"Stonestrom","given":"David","email":"dastones@usgs.gov","middleInitial":"A.","affiliations":[{"id":438,"text":"National Research Program - Western Branch","active":true,"usgs":true}],"preferred":true,"id":725900,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":85389,"text":"85389 - 1998 - Wetland birds in the northern Great Plains","interactions":[],"lastModifiedDate":"2017-12-27T11:31:30","indexId":"85389","displayToPublicDate":"1998-01-01T00:00:00","publicationYear":"1998","noYear":false,"publicationType":{"id":5,"text":"Book chapter"},"publicationSubtype":{"id":24,"text":"Book Chapter"},"title":"Wetland birds in the northern Great Plains","docAbstract":"When the Wisconsin glacier retreated about 10,000 years ago, it left innumerable depressions scattered throughout the northern Great Plains. These depressional wetlands, called prairie potholes, contain water for various lengths of time in most years (Kantrud et al. 1989). Their size, permanence, hydrology, water chemistry, plant associations, and invertebrate communities vary widely among wetlands and, within a basin, through time (Cowardin et al. 1979).
These diverse wetlands support a breeding avifauna as rich and varied as the wetlands themselves. Johnsgard (1979) listed 72 breeding bird species associated with freshwater pond environments in the Great Plains. Other species, such as the northern harrier, marbled godwit, Le Conte’s sparrow, and Nelson’s sharp-tailed sparrow, are associated with grasslands but extensively use these prairie wetlands. Stewart (1975) identified 63 breeding bird species as wetland associates in North Dakota alone. Since 1975, several species could be added to Stewart’s list (Faanes and Stewart 1982), including the reintroduced Canada goose (Lee et al. 1989) and several herons, egrets, and ibises that have expanded their breeding range into the state (Lokemoen 1979). Most wetland birds are short-distance migrants, wintering primarily north of the United States–Mexico border (Igl and Johnson 1995).
","largerWorkType":{"id":4,"text":"Book"},"largerWorkTitle":"Status and trends of the nation's biological resources","largerWorkSubtype":{"id":15,"text":"Monograph"},"language":"English","publisher":"U.S. Geological Survey","publisherLocation":"Washington, D.C.","usgsCitation":"Igl, L.D., and Johnson, D.H., 1998, Wetland birds in the northern Great Plains, chap. of Status and trends of the nation's biological resources, p. 454-455.","productDescription":"2 p.","startPage":"454","endPage":"455","costCenters":[{"id":480,"text":"Northern Prairie Wildlife Research Center","active":true,"usgs":true}],"links":[{"id":127942,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"},{"id":11457,"rank":200,"type":{"id":11,"text":"Document"},"url":"https://www.nwrc.usgs.gov/sandt/Grasslnd.pdf"}],"noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e49e2e4b07f02db5e49fc","contributors":{"editors":[{"text":"Mac, M. J.","contributorId":44492,"corporation":false,"usgs":true,"family":"Mac","given":"M. J.","affiliations":[],"preferred":false,"id":504472,"contributorType":{"id":2,"text":"Editors"},"rank":1},{"text":"Opler, P.A.","contributorId":48521,"corporation":false,"usgs":true,"family":"Opler","given":"P.A.","affiliations":[],"preferred":false,"id":504473,"contributorType":{"id":2,"text":"Editors"},"rank":2},{"text":"Puckett Haecker, C. E.","contributorId":114075,"corporation":false,"usgs":true,"family":"Puckett Haecker","given":"C.","email":"","middleInitial":"E.","affiliations":[],"preferred":false,"id":504475,"contributorType":{"id":2,"text":"Editors"},"rank":3},{"text":"Doran, P.D.","contributorId":113343,"corporation":false,"usgs":true,"family":"Doran","given":"P.D.","email":"","affiliations":[],"preferred":false,"id":504474,"contributorType":{"id":2,"text":"Editors"},"rank":4}],"authors":[{"text":"Igl, Lawrence D. 0000-0003-0530-7266 ligl@usgs.gov","orcid":"https://orcid.org/0000-0003-0530-7266","contributorId":2381,"corporation":false,"usgs":true,"family":"Igl","given":"Lawrence","email":"ligl@usgs.gov","middleInitial":"D.","affiliations":[{"id":480,"text":"Northern Prairie Wildlife Research Center","active":true,"usgs":true}],"preferred":true,"id":296005,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Johnson, Douglas H. 0000-0002-7778-6641 douglas_h_johnson@usgs.gov","orcid":"https://orcid.org/0000-0002-7778-6641","contributorId":1387,"corporation":false,"usgs":true,"family":"Johnson","given":"Douglas","email":"douglas_h_johnson@usgs.gov","middleInitial":"H.","affiliations":[{"id":480,"text":"Northern Prairie Wildlife Research Center","active":true,"usgs":true}],"preferred":true,"id":296006,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":70021102,"text":"70021102 - 1998 - Salinity trends in surface waters of the Upper Colorado River Basin, Colorado","interactions":[],"lastModifiedDate":"2024-03-29T11:20:35.700744","indexId":"70021102","displayToPublicDate":"1998-01-01T00:00:00","publicationYear":"1998","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":2262,"text":"Journal of Environmental Quality","active":true,"publicationSubtype":{"id":10}},"title":"Salinity trends in surface waters of the Upper Colorado River Basin, Colorado","docAbstract":"Dissolved-solids data collected in the Upper Colorado River Basin upstream from Cameo, Colorado, and in the Gunnison River Basin were analyzed for trends in flow-adjusted dissolved-solids concentrations and loads for water years 1970 to 1993, 1980 to 1993, and 1986 to 1993. Trend results for flow-adjusted periodic dissolved-solids concentrations for the Colorado River Basin upstream from Cameo, CO, generally were downward or no trend was indicated. Trends in flow-adjusted monthly and annual dissolved-solids loads primarily were downward or absent. These trend results partly agree with the downward trends reported by a previous investigation for the Colorado River near Cameo site. In the Gunnison River Basin, trends in flow-adjusted dissolved-solids concentrations and loads were not detected for more than one-half of the site/analysis-period combinations. Of the trends that were present, most indicated decreases in concentrations and loads rather than increases. In both the Colorado River Basin upstream from Cameo, CO, and the Gunnison River Basin, trends in flow-adjusted dissolved-solids concentrations and flow-adjusted monthly and annual dissolved-solids loads may be affected by a variety of factors. These include channel evolution and hydrologic variation, water quality and flow rate of groundwater discharges and springs, sample size and period of record of dissolved-solids data, and changes in land use in the basin.
The work reported here is the first part of a larger effort focused on efficient numerical simulation of redox zone development in contaminated aquifers. The sequential use of various electron acceptors, which is governed by the energy yield of each reaction, gives rise to redox zones. The large difference in energy yields between the various redox reactions leads to systems of equations that are extremely ill-conditioned. These equations are very difficult to solve, especially in the context of coupled fluid flow, solute transport, and geochemical simulations. We have developed a general, rational method to solve such systems where we focus on the dominant reactions, compartmentalizing them in a manner that is analogous to the redox zones that are often observed in the field. The compartmentalized approach allows us to easily solve a complex geochemical system as a function of time and energy yield, laying the foundation for our ongoing work in which we couple the reaction network, for the development of redox zones, to a model of subsurface fluid flow and solute transport. Our method (1) solves the numerical system without evoking a redox parameter, (2) improves the numerical stability of redox systems by choosing which compartment and thus which reaction network to use based upon the concentration ratios of key constituents, (3) simulates the development of redox zones as a function of time without the use of inhibition factors or switching functions, and (4) can reduce the number of transport equations that need to be solved in space and time. We show through the use of various model performance evaluation statistics that the appropriate compartment choice under different geochemical conditions leads to numerical solutions without significant error. The compartmentalized approach described here facilitates the next phase of this effort where we couple the redox zone reaction network to models of fluid flow and solute transport.
","language":"English","publisher":"American Geophysical Union","doi":"10.1029/98WR00485","usgsCitation":"Abrams , R., Loague, K., and Kent, D.B., 1998, Development and testing of a compartmentalized reaction network model for redox zones in contaminated aquifers: Water Resources Research, v. 34, no. 6, p. 1531-1541, https://doi.org/10.1029/98WR00485.","productDescription":"11 p.","startPage":"1531","endPage":"1541","costCenters":[{"id":589,"text":"Toxic Substances Hydrology Program","active":true,"usgs":true}],"links":[{"id":479819,"rank":1,"type":{"id":40,"text":"Open Access Publisher Index Page"},"url":"https://doi.org/10.1029/98wr00485","text":"Publisher Index Page"},{"id":231215,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"34","issue":"6","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505a0027e4b0c8380cd4f5f9","contributors":{"authors":[{"text":"Abrams , Robert H.","contributorId":189399,"corporation":false,"usgs":false,"family":"Abrams ","given":"Robert H.","affiliations":[],"preferred":false,"id":385921,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Loague, Keith","contributorId":178119,"corporation":false,"usgs":false,"family":"Loague","given":"Keith","email":"","affiliations":[],"preferred":false,"id":385922,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Kent, Douglas B. 0000-0003-3758-8322 dbkent@usgs.gov","orcid":"https://orcid.org/0000-0003-3758-8322","contributorId":1871,"corporation":false,"usgs":true,"family":"Kent","given":"Douglas","email":"dbkent@usgs.gov","middleInitial":"B.","affiliations":[{"id":37277,"text":"WMA - Earth System Processes Division","active":true,"usgs":true}],"preferred":true,"id":385920,"contributorType":{"id":1,"text":"Authors"},"rank":3}]}} ,{"id":70021078,"text":"70021078 - 1998 - Exchanges of sediment between the flood plain and channel of the Amazon River in Brazil","interactions":[],"lastModifiedDate":"2023-12-20T12:18:54.969938","indexId":"70021078","displayToPublicDate":"1998-01-01T00:00:00","publicationYear":"1998","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1786,"text":"Geological Society of America Bulletin","active":true,"publicationSubtype":{"id":10}},"title":"Exchanges of sediment between the flood plain and channel of the Amazon River in Brazil","docAbstract":"Sediment transport through the Brazilian sector of the Amazon River valley, a distance of 2010 km, involves exchanges between the channel and the flood plain that in each direction exceed the annual flux of sediment out of the river at Óbidos (∼1200 Mt yr−1). The exchanges occur through bank erosion, bar deposition, settling from diffuse overbank flow, and sedimentation in flood-plain channels. We estimated the magnitude of these exchanges for each of 10 reaches of the valley, and combined them with calculations of sediment transport into and out of the reaches based on sediment sampling and flow records to define a sediment budget for each reach. Residuals in the sediment budget of a reach include errors of estimation and erosion or deposition within the channel. The annual supply of sediment entering the channel from bank erosion was estimated to average 1570 Mt yr−1 (1.3 × the Óbidos flux) and the amount transferred from channel transport to the bars (380 Mt yr−1) and the flood plain (460 Mt yr−1 in channelized flow; 1230 Mt yr−1 in diffuse overbank flow) totaled 2070 Mt yr−1 (1.7 × the Óbidos flux). Thus, deposition on the bars and flood plain exceeded bank erosion by 500 Mt yr−1 over a 10–16 yr period. Sampling and calculation of sediment loads in the channel indicate a net accumulation in the valley floor of approximately 200 Mt yr−1 over 16 yr, crudely validating the process-based calculations of the sediment budget, which in turn illuminate the physical controls on each exchange process. Another 300–400 Mt yr−1 are deposited in a delta plain downstream of Óbidos. The components of the sediment budget reflect hydrologic characteristics of the valley floor and geomorphic characteristics of the channel and flood plain, which in turn are influenced by tectonic features of the Amazon structural trough.
A multispecies numerical code was developed to simulate flow and mass transport with kinetic adsorption in variable-density flow systems. The two-dimensional code simulated the transport of bromide (Br−), a nonreactive tracer, and lithium (Li+), a reactive tracer, in a large-scale tracer test performed in a sand-and-gravel aquifer at Cape Cod, Massachusetts. A two-fraction kinetic adsorption model was implemented to simulate the interaction of Li+ with the aquifer solids. Initial estimates for some of the transport parameters were obtained from a nonlinear least squares curve-fitting procedure, where the breakthrough curves from column experiments were matched with one-dimensional theoretical models. The numerical code successfully simulated the basic characteristics of the two plumes in the tracer test. At early times the centers of mass of Br− and Li+ sank because the two plumes were closely coupled to the density-driven velocity field. At later times the rate of downward movement in the Br− plume due to gravity slowed significantly because of dilution by dispersion. The downward movement of the Li+ plume was negligible because the two plumes moved in locally different velocity regimes, where Li+ transport was retarded relative to Br−. The maximum extent of downward transport of the Li+ plume was less than that of the Br− plume. This study also found that at early times the downward movement of a plume created by a three-dimensional source could be much more extensive than the case with a two-dimensional source having the same cross-sectional area. The observed shape of the Br− plume at Cape Cod was simulated by adding two layers with different hydraulic conductivities at shallow depth across the region. The large dispersion and asymmetrical shape of the Li+ plume were simulated by including kinetic adsorption-desorption reactions.
","language":"English","publisher":"American Geophysical Union","doi":"10.1029/97WR02918","usgsCitation":"Zhang, H., Schwartz, F.W., Wood, W., Garabedian, S., and LeBlanc, D., 1998, Simulation of variable-density flow and transport of reactive and nonreactive solutes during a tracer test at Cape Cod, Massachusetts: Water Resources Research, v. 34, no. 1, p. 67-82, https://doi.org/10.1029/97WR02918.","productDescription":"16 p.","startPage":"67","endPage":"82","costCenters":[{"id":589,"text":"Toxic Substances Hydrology Program","active":true,"usgs":true}],"links":[{"id":487377,"rank":1,"type":{"id":40,"text":"Open Access Publisher Index Page"},"url":"https://doi.org/10.1029/97wr02918","text":"Publisher Index Page"},{"id":230087,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"country":"United States","state":"Massachusetts","otherGeospatial":"Cape Cod","volume":"34","issue":"1","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505b90b6e4b08c986b31963e","contributors":{"authors":[{"text":"Zhang, Hubao","contributorId":196105,"corporation":false,"usgs":false,"family":"Zhang","given":"Hubao","email":"","affiliations":[],"preferred":false,"id":388339,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Schwartz, Frank W.","contributorId":196083,"corporation":false,"usgs":false,"family":"Schwartz","given":"Frank","email":"","middleInitial":"W.","affiliations":[],"preferred":false,"id":388338,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Wood, Warren W.","contributorId":47770,"corporation":false,"usgs":false,"family":"Wood","given":"Warren W.","affiliations":[{"id":6601,"text":"Michigan State University","active":true,"usgs":false}],"preferred":false,"id":388337,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Garabedian, S. P.","contributorId":56657,"corporation":false,"usgs":true,"family":"Garabedian","given":"S. P.","affiliations":[],"preferred":false,"id":388340,"contributorType":{"id":1,"text":"Authors"},"rank":4},{"text":"LeBlanc, D.R.","contributorId":87141,"corporation":false,"usgs":true,"family":"LeBlanc","given":"D.R.","email":"","affiliations":[],"preferred":false,"id":388341,"contributorType":{"id":1,"text":"Authors"},"rank":5}]}} ]}