{"pageNumber":"345","pageRowStart":"8600","pageSize":"25","recordCount":16445,"records":[{"id":70022986,"text":"70022986 - 2001 - Predictions of hydrothermal alteration within near-ridge oceanic crust from coordinated geochemical and fluid flow models","interactions":[],"lastModifiedDate":"2018-03-21T15:38:21","indexId":"70022986","displayToPublicDate":"2001-01-01T00:00:00","publicationYear":"2001","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":2499,"text":"Journal of Volcanology and Geothermal Research","active":true,"publicationSubtype":{"id":10}},"title":"Predictions of hydrothermal alteration within near-ridge oceanic crust from coordinated geochemical and fluid flow models","docAbstract":"Coordinated geochemical and hydrological calculations guide our understanding of the composition, fluid flow patterns, and thermal structure of near-ridge oceanic crust. The case study presented here illustrates geochemical and thermal changes taking place as oceanic crust ages from 0.2 to 1.0 Myr. Using a finite element code, we model fluid flow and heat transport through the upper few hundred meters of an abyssal hill created at an intermediate spreading rate. We use a reaction path model with a customized database to calculate equilibrium fluid compositions and mineral assemblages of basalt and seawater at 500 bars and temperatures ranging from 150 to 400??C. In one scenario, reaction path calculations suggest that volume increases on the order of 10% may occur within portions of the basaltic basement. If this change in volume occurred, it would be sufficient to fill all primary porosity in some locations, effectively sealing off portions of the oceanic crust. Thermal profiles resulting from fluid flow simulations indicate that volume changes along this possible reaction path occur primarily within the first 0.4 Myr of crustal aging. ?? 2001 Elsevier Science B.V. All rights reserved.","largerWorkType":{"id":2,"text":"Article"},"largerWorkTitle":"Journal of Volcanology and Geothermal Research","largerWorkSubtype":{"id":10,"text":"Journal Article"},"language":"English","doi":"10.1016/S0377-0273(01)00215-3","issn":"03770273","usgsCitation":"Wetzel, L., Raffensperger, J.P., and Shock, E., 2001, Predictions of hydrothermal alteration within near-ridge oceanic crust from coordinated geochemical and fluid flow models: Journal of Volcanology and Geothermal Research, v. 110, no. 3-4, p. 319-342, https://doi.org/10.1016/S0377-0273(01)00215-3.","startPage":"319","endPage":"342","numberOfPages":"24","costCenters":[],"links":[{"id":233545,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"},{"id":208103,"rank":9999,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.1016/S0377-0273(01)00215-3"}],"volume":"110","issue":"3-4","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505a81fae4b0c8380cd7b830","contributors":{"authors":[{"text":"Wetzel, L.R.","contributorId":9525,"corporation":false,"usgs":true,"family":"Wetzel","given":"L.R.","email":"","affiliations":[],"preferred":false,"id":395701,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Raffensperger, Jeff P. 0000-0001-9275-6646 jpraffen@usgs.gov","orcid":"https://orcid.org/0000-0001-9275-6646","contributorId":199119,"corporation":false,"usgs":true,"family":"Raffensperger","given":"Jeff","email":"jpraffen@usgs.gov","middleInitial":"P.","affiliations":[{"id":374,"text":"Maryland Water Science Center","active":true,"usgs":true}],"preferred":true,"id":395703,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Shock, E.L.","contributorId":54071,"corporation":false,"usgs":true,"family":"Shock","given":"E.L.","email":"","affiliations":[],"preferred":false,"id":395702,"contributorType":{"id":1,"text":"Authors"},"rank":3}]}}
,{"id":70022990,"text":"70022990 - 2001 - Delineating a recharge area for a spring using numerical modeling, Monte Carlo techniques, and geochemical investigation","interactions":[],"lastModifiedDate":"2018-12-03T09:41:59","indexId":"70022990","displayToPublicDate":"2001-01-01T00:00:00","publicationYear":"2001","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1861,"text":"Ground Water","active":true,"publicationSubtype":{"id":10}},"title":"Delineating a recharge area for a spring using numerical modeling, Monte Carlo techniques, and geochemical investigation","docAbstract":"Recharge areas of spring systems can be hard to identify, but they can be critically important for protection of a spring resource. A recharge area for a spring complex in southern Wisconsin was delineated using a variety of complementary techniques. A telescopic mesh refinement (TMR) model was constructed from an existing regional-scale ground water flow model. This TMR model was formally optimized using parameter estimation techniques; the optimized \"best fit\" to measured heads and fluxes was obtained by using a horizontal hydraulic conductivity 200% larger than the original regional model for the upper bedrock aquifer and 80% smaller for the lower bedrock aquifer. The uncertainty in hydraulic conductivity was formally considered using a stochastic Monte Carlo approach. Two-hundred model runs used uniformly distributed, randomly sampled, horizontal hydraulic conductivity values within the range given by the TMR optimized values and the previously constructed regional model. A probability distribution of particles captured by the spring, or a \"probabilistic capture zone,\" was calculated from the realistic Monte Carlo results (136 runs of 200). In addition to portions of the local surface watershed, the capture zone encompassed areas outside of the watershed - demonstrating that the ground watershed and surface watershed do not coincide. Analysis of water collected from the site identified relatively large contrasts in chemistry, even for springs within 15 m of one another. The differences showed a distinct gradation from Ordovician-carbonate-dominated water in western spring vents to Cambrian-sandstone-influenced water in eastern spring vents. The difference in chemistry was attributed to distinctive bedrock geology as demonstrated by overlaying the capture zone derived from numerical modeling over a bedrock geology map for the area. This finding gives additional confidence to the capture zone calculated by modeling.","language":"English","publisher":"Wiley","doi":"10.1111/j.1745-6584.2001.tb02360.x","issn":"0017467X","usgsCitation":"Hunt, R.J., Steuer, J.J., Mansor, M., and Bullen, T., 2001, Delineating a recharge area for a spring using numerical modeling, Monte Carlo techniques, and geochemical investigation: Ground Water, v. 39, no. 5, p. 702-712, https://doi.org/10.1111/j.1745-6584.2001.tb02360.x.","productDescription":"11 p.","startPage":"702","endPage":"712","costCenters":[{"id":589,"text":"Toxic Substances Hydrology Program","active":true,"usgs":true}],"links":[{"id":233582,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"39","issue":"5","noUsgsAuthors":false,"publicationDate":"2005-12-13","publicationStatus":"PW","scienceBaseUri":"5059fe60e4b0c8380cd4ece1","contributors":{"authors":[{"text":"Hunt, R. J.","contributorId":40164,"corporation":false,"usgs":true,"family":"Hunt","given":"R.","email":"","middleInitial":"J.","affiliations":[],"preferred":false,"id":395710,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Steuer, J. J.","contributorId":12430,"corporation":false,"usgs":true,"family":"Steuer","given":"J.","email":"","middleInitial":"J.","affiliations":[],"preferred":false,"id":395709,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Mansor, M.T.C.","contributorId":85370,"corporation":false,"usgs":true,"family":"Mansor","given":"M.T.C.","email":"","affiliations":[],"preferred":false,"id":395712,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Bullen, T.D.","contributorId":79911,"corporation":false,"usgs":true,"family":"Bullen","given":"T.D.","email":"","affiliations":[],"preferred":false,"id":395711,"contributorType":{"id":1,"text":"Authors"},"rank":4}]}}
,{"id":70023023,"text":"70023023 - 2001 - Effect of basin physical characteristics on solute fluxes in nine alpine/subalpine basins, Colorado, USA","interactions":[],"lastModifiedDate":"2012-03-12T17:20:06","indexId":"70023023","displayToPublicDate":"2001-01-01T00:00:00","publicationYear":"2001","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1924,"text":"Hydrological Processes","active":true,"publicationSubtype":{"id":10}},"title":"Effect of basin physical characteristics on solute fluxes in nine alpine/subalpine basins, Colorado, USA","docAbstract":"Alpine/subalpine basins may exhibit substantial variability in solute fluxes despite many apparent similarities in basin characteristics. An evaluation of controls on spatial patterns in solute fluxes may allow development of predictive tools for assessing basin sensitivity to outside perturbations such as climate change or deposition of atmospheric pollutants. Relationships between basin physical characteristics, determined from geographical information system (GIS) tools, and solute fluxes and mineral weathering rates were explored for nine alpine/subalpine basins in Rocky Mountain National Park, Colorado, using correlation analyses for 1993 and 1994 data. Stream-water nitrate fluxes were correlated positively with basin characteristics associated with the talus environment; i.e., the fractional amounts of steep slopes (??? 30??), unvegetated terrain and young debris (primarily Holocene till) in the basins, and were correlated negatively with fractional amounts of subalpine meadow terrain. Correlations with nitrate indicate the importance of the talus environment in promoting nitrate flux and the mitigating effect of areas with established vegetation, such as subalpine meadows. Total mineral weathering rates for the basins ranged from about 300 to 600 mol ha-1 year -1. Oligoclase weathering accounted for 30 to 73% of the total mineral weathering flux, and was positively correlated with the amount of old debris (primarily Pleistocene glacial till) in the basins. Although calcite is found in trace amounts in bedrock, calcite weathering accounted for up to 44% of the total mineral weathering flux. Calcite was strongly correlated with steep slope, unvegetated terrain, and young debris-probably because physical weathering in steep-gradient areas exposes fresh mineral surfaces that contain calcite for chemical weathering. Oligoclase and calcite weathering are the dominant sources of alkalinity in the basins. However, atmospherically deposited acids consume much of the alkalinity generated by weathering of calcite and other minerals in the talus environment. Published in 2001 by John Wiley and Sons, Ltd.","largerWorkType":{"id":2,"text":"Article"},"largerWorkTitle":"Hydrological Processes","largerWorkSubtype":{"id":10,"text":"Journal Article"},"language":"English","doi":"10.1002/hyp.265","issn":"08856087","usgsCitation":"Sueker, J., Clow, D.W., Ryan, J.N., and Jarrett, R., 2001, Effect of basin physical characteristics on solute fluxes in nine alpine/subalpine basins, Colorado, USA: Hydrological Processes, v. 15, no. 14, p. 2749-2769, https://doi.org/10.1002/hyp.265.","startPage":"2749","endPage":"2769","numberOfPages":"21","costCenters":[],"links":[{"id":498976,"rank":10000,"type":{"id":40,"text":"Open Access Publisher Index Page"},"url":"https://doi.org/10.1002/hyp.265","text":"Publisher Index Page"},{"id":233508,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"},{"id":208089,"rank":9999,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.1002/hyp.265"}],"volume":"15","issue":"14","noUsgsAuthors":false,"publicationDate":"2001-10-02","publicationStatus":"PW","scienceBaseUri":"505a05c2e4b0c8380cd50f40","contributors":{"authors":[{"text":"Sueker, J.K.","contributorId":61977,"corporation":false,"usgs":true,"family":"Sueker","given":"J.K.","email":"","affiliations":[],"preferred":false,"id":395841,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Clow, D. W.","contributorId":23531,"corporation":false,"usgs":true,"family":"Clow","given":"D.","email":"","middleInitial":"W.","affiliations":[],"preferred":false,"id":395839,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Ryan, J. N.","contributorId":102649,"corporation":false,"usgs":true,"family":"Ryan","given":"J.","email":"","middleInitial":"N.","affiliations":[],"preferred":false,"id":395842,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Jarrett, R.D.","contributorId":36551,"corporation":false,"usgs":true,"family":"Jarrett","given":"R.D.","email":"","affiliations":[],"preferred":false,"id":395840,"contributorType":{"id":1,"text":"Authors"},"rank":4}]}}
,{"id":70023026,"text":"70023026 - 2001 - Developing a post-fire flood chronology and recurrence probability from alluvial stratigraphy in the Buffalo Creek watershed, Colorado, USA","interactions":[],"lastModifiedDate":"2012-03-12T17:20:05","indexId":"70023026","displayToPublicDate":"2001-01-01T00:00:00","publicationYear":"2001","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1924,"text":"Hydrological Processes","active":true,"publicationSubtype":{"id":10}},"title":"Developing a post-fire flood chronology and recurrence probability from alluvial stratigraphy in the Buffalo Creek watershed, Colorado, USA","docAbstract":"Stratigraphic and geomorphic evidence indicate floods that occur soon after forest fires have been intermittent but common events in many mountainous areas during the past several thousand years. The magnitude and recurrence of these post-fire flood events reflects the joint probability between the recurrence of fires and the recurrence of subsequent rainfall events of varying magnitude and intensity. Following the May 1996 Buffalo Creek, Colorado, forest fire, precipitation amounts and intensities that generated very little surface runoff outside of the burned area resulted in severe hillslope erosion, floods, and streambed sediment entrainment in the rugged, severely burned, 48 km2 area. These floods added sediment to many existing alluvial fans, while simultaneously incising other fans and alluvial deposits. Incision of older fans revealed multiple sequences of fluvially transported sandy gravel that grade upward into charcoal-rich, loamy horizons. We interpret these sequences to represent periods of high sediment transport and aggradation during floods, followed by intervals of quiescence and relative stability in the watershed until a subsequent fire occurred. An alluvial sequence near the mouth of a tributary draining a 0??82 km2 area indicated several previous post-fire flood cycles in the watershed. Dendrochronologic and radiocarbon ages of material in this deposit span approximately 2900 years, and define three aggradational periods. The three general aggradational periods are separated by intervals of approximately nine to ten centuries and reflect a 'millennium-scale' geomorphic response to a closely timed sequence of events: severe and intense, watershed-scale, stand-replacing fires and subsequent rainstorms and flooding. Millennium-scale aggradational units at the study site may have resulted from a scenario in which the initial runoff from the burned watershed transported and deposited large volumes of sediment on downstream alluvial surfaces and tributary fans. Subsequent storm runoff may have produced localized incision and channelization, preventing additional vertical aggradation on the sampled alluvial deposit for several centuries. Two of the millennium-scale aggradational periods at the study site consist of multiple gravel and loam sequences with similar radiocarbon ages. These closely dated sequences may reflect a 'multidecade-scale' geomorphic response to more frequent, but aerially limited and less severe fires, followed by rainstorms of relatively common recurrence. Published in 2001 by John Wiley and Sons, Ltd.","largerWorkType":{"id":2,"text":"Article"},"largerWorkTitle":"Hydrological Processes","largerWorkSubtype":{"id":10,"text":"Journal Article"},"language":"English","doi":"10.1002/hyp.390","issn":"08856087","usgsCitation":"Elliott, J.G., and Parker, R.S., 2001, Developing a post-fire flood chronology and recurrence probability from alluvial stratigraphy in the Buffalo Creek watershed, Colorado, USA: Hydrological Processes, v. 15, no. 15, p. 3039-3051, https://doi.org/10.1002/hyp.390.","startPage":"3039","endPage":"3051","numberOfPages":"13","costCenters":[],"links":[{"id":208121,"rank":9999,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.1002/hyp.390"},{"id":233584,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"15","issue":"15","noUsgsAuthors":false,"publicationDate":"2001-10-25","publicationStatus":"PW","scienceBaseUri":"505a000be4b0c8380cd4f560","contributors":{"authors":[{"text":"Elliott, J. G.","contributorId":45341,"corporation":false,"usgs":true,"family":"Elliott","given":"J.","email":"","middleInitial":"G.","affiliations":[],"preferred":false,"id":395857,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Parker, R. S.","contributorId":104510,"corporation":false,"usgs":true,"family":"Parker","given":"R.","email":"","middleInitial":"S.","affiliations":[],"preferred":false,"id":395858,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}}
,{"id":70023058,"text":"70023058 - 2001 - Ecosystem processes and nitrogen export in northern U.S. watersheds.","interactions":[],"lastModifiedDate":"2013-03-11T12:49:54","indexId":"70023058","displayToPublicDate":"2001-01-01T00:00:00","publicationYear":"2001","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":3359,"text":"Scientific World Journal","active":true,"publicationSubtype":{"id":10}},"title":"Ecosystem processes and nitrogen export in northern U.S. watersheds.","docAbstract":"There is much interest in the relationship of atmospheric nitrogen (N) inputs to ecosystem outputs as an indicator of possible \"nitrogen saturation\" by human activity. Longer-term, ecosystem-level mass balance studies suggest that the relationship is not clear and that other ecosystem processes may dominate variation in N outputs. We have been studying small, forested watershed ecosystems in five northern watersheds for periods up to 35 years. Here I summarize the research on ecosystem processes and the N budget. During the past 2 decades, average wet-precipitation N inputs ranged from about 0.1 to 6 kg N ha(-1) year(-1) among sites. In general, sites with the lowest N inputs had the highest output-to-input ratios. In the Alaska watersheds, streamwater N output exceeded inputs by 70 to 250%. The ratio of mean monthly headwater nitrate (NO3-) concentration to precipitation NO3- concentration declined with increased precipitation concentration. A series of ecosystem processes have been studied and related to N outputs. The most important appear to be seasonal change in hydrologic flowpath, soil freezing, seasonal forest-floor inorganic N pools resulting from over-winter mineralization beneath the snowpack, spatial variation in watershed forest-floor inorganic N pools, the degree to which snowmelt percolates soils, and gross soil N mineralization rates.","largerWorkType":{"id":2,"text":"Article"},"largerWorkTitle":"Scientific World Journal","largerWorkSubtype":{"id":10,"text":"Journal Article"},"language":"English","publisher":"Hindawi Publishong","doi":"10.1100/tsw.2001.328","issn":"1537744X","usgsCitation":"Stottlemyer, R., 2001, Ecosystem processes and nitrogen export in northern U.S. watersheds.: Scientific World Journal, v. 1, no. Suppl 2, p. 581-588, https://doi.org/10.1100/tsw.2001.328.","startPage":"581","endPage":"588","numberOfPages":"8","costCenters":[],"links":[{"id":479009,"rank":1,"type":{"id":40,"text":"Open Access Publisher Index Page"},"url":"https://doi.org/10.1100/tsw.2001.328","text":"Publisher Index Page"},{"id":233550,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"},{"id":269041,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.1100/tsw.2001.328"}],"volume":"1","issue":"Suppl 2","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505a059fe4b0c8380cd50e9c","contributors":{"authors":[{"text":"Stottlemyer, R.","contributorId":44493,"corporation":false,"usgs":true,"family":"Stottlemyer","given":"R.","email":"","affiliations":[],"preferred":false,"id":395995,"contributorType":{"id":1,"text":"Authors"},"rank":1}]}}
,{"id":70023087,"text":"70023087 - 2001 - Choosing between atmospheric pressure chemical ionization and electrospray ionization interfaces for the HPLC/MS analysis of pesticides","interactions":[],"lastModifiedDate":"2018-11-30T06:52:10","indexId":"70023087","displayToPublicDate":"2001-01-01T00:00:00","publicationYear":"2001","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":761,"text":"Analytical Chemistry","active":true,"publicationSubtype":{"id":10}},"title":"Choosing between atmospheric pressure chemical ionization and electrospray ionization interfaces for the HPLC/MS analysis of pesticides","docAbstract":"An evaluation of over 75 pesticides by high-performance liquid chromatography/mass spectrometry (HPLC/MS) clearly shows that different classes of pesticides are more sensitive using either atmospheric pressure chemical ionization (APCI) or electrospray ionization (ESI). For example, neutral and basic pesticides (phenylureas, triazines) are more sensitive using APCI (especially positive ion). While cationic and anionic herbicides (bipyridylium ions, sulfonic acids) are more sensitive using ESI (especially negative ion). These data are expressed graphically in a figure called an ionization-continuum diagram, which shows that protonation in the gas phase (proton affinity) and polarity in solution, expressed as proton addition or subtraction (pKa), is useful in selecting APCI or ESI. Furthermore, sodium adduct formation commonly occurs using positive ion ESI but not using positive ion APCI, which reflects the different mechanisms of ionization and strengthens the usefulness of the ionization-continuum diagram. The data also show that the concept of \"wrong-way around\" ESI (the sensitivity of acidic pesticides in an acidic mobile phase) is a useful modification of simple pKa theory for mobile-phase selection. Finally, this finding is used to enhance the chromatographic separation of oxanilic and sulfonic acid herbicides while maintaining good sensitivity in LC/MS using ESI negative.","language":"English","doi":"10.1021/ac010506f","issn":"00032700","usgsCitation":"Thurman, E., Ferrer, I., and Barcelo, D., 2001, Choosing between atmospheric pressure chemical ionization and electrospray ionization interfaces for the HPLC/MS analysis of pesticides: Analytical Chemistry, v. 73, no. 22, p. 5441-5449, https://doi.org/10.1021/ac010506f.","productDescription":"9 p.","startPage":"5441","endPage":"5449","costCenters":[{"id":589,"text":"Toxic Substances Hydrology Program","active":true,"usgs":true}],"links":[{"id":233370,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"},{"id":208016,"rank":9999,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.1021/ac010506f"}],"volume":"73","issue":"22","noUsgsAuthors":false,"publicationDate":"2001-10-09","publicationStatus":"PW","scienceBaseUri":"5059f5d7e4b0c8380cd4c45e","contributors":{"authors":[{"text":"Thurman, E.M.","contributorId":102864,"corporation":false,"usgs":true,"family":"Thurman","given":"E.M.","affiliations":[],"preferred":false,"id":396089,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Ferrer, I.","contributorId":97260,"corporation":false,"usgs":true,"family":"Ferrer","given":"I.","email":"","affiliations":[],"preferred":false,"id":396088,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Barcelo, D.","contributorId":24107,"corporation":false,"usgs":true,"family":"Barcelo","given":"D.","affiliations":[],"preferred":false,"id":396087,"contributorType":{"id":1,"text":"Authors"},"rank":3}]}}
,{"id":70023091,"text":"70023091 - 2001 - Geomorphologic evidence for liquid water","interactions":[],"lastModifiedDate":"2012-03-12T17:20:07","indexId":"70023091","displayToPublicDate":"2001-01-01T00:00:00","publicationYear":"2001","noYear":false,"publicationType":{"id":24,"text":"Conference Paper"},"publicationSubtype":{"id":19,"text":"Conference Paper"},"title":"Geomorphologic evidence for liquid water","docAbstract":"Besides Earth, Mars is the only planet with a record of resurfacing processes and environmental circumstances that indicate the past operation of a hydrologic cycle. However the present-day conditions on Mars are far apart of supporting liquid water on the surface. Although the large-scale morphology of the Martian channels and valleys show remarkable similarities with fluid-eroded features on Earth, there are major differences in their size, small-scale morphology, inner channel structure and source regions indicating that the erosion on Mars has its own characteristic genesis and evolution. The different landforms related to fluvial, glacial and periglacial activities, their relations with volcanism, and the chronology of water-related processes, are presented.","largerWorkTitle":"Space Science Reviews","language":"English","doi":"10.1023/A:1011913809715","issn":"00386308","usgsCitation":"Masson, P., Carr, M.H., Costard, F., Greeley, R., Hauber, E., and Jaumann, R., 2001, Geomorphologic evidence for liquid water, <i>in</i> Space Science Reviews, v. 96, no. 1-4, p. 333-364, https://doi.org/10.1023/A:1011913809715.","startPage":"333","endPage":"364","numberOfPages":"32","costCenters":[],"links":[{"id":208054,"rank":9999,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.1023/A:1011913809715"},{"id":233439,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"96","issue":"1-4","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505a279de4b0c8380cd59a4a","contributors":{"authors":[{"text":"Masson, P.","contributorId":21318,"corporation":false,"usgs":true,"family":"Masson","given":"P.","email":"","affiliations":[],"preferred":false,"id":396140,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Carr, M. H.","contributorId":84727,"corporation":false,"usgs":true,"family":"Carr","given":"M.","email":"","middleInitial":"H.","affiliations":[{"id":131,"text":"Astrogeology Science Center","active":true,"usgs":true}],"preferred":false,"id":396144,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Costard, F.","contributorId":61214,"corporation":false,"usgs":true,"family":"Costard","given":"F.","email":"","affiliations":[],"preferred":false,"id":396141,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Greeley, R.","contributorId":6538,"corporation":false,"usgs":true,"family":"Greeley","given":"R.","email":"","affiliations":[],"preferred":false,"id":396139,"contributorType":{"id":1,"text":"Authors"},"rank":4},{"text":"Hauber, E.","contributorId":81659,"corporation":false,"usgs":true,"family":"Hauber","given":"E.","affiliations":[],"preferred":false,"id":396143,"contributorType":{"id":1,"text":"Authors"},"rank":5},{"text":"Jaumann, R.","contributorId":81232,"corporation":false,"usgs":false,"family":"Jaumann","given":"R.","email":"","affiliations":[],"preferred":false,"id":396142,"contributorType":{"id":1,"text":"Authors"},"rank":6}]}}
,{"id":70024043,"text":"70024043 - 2001 - The national stream quality accounting network: A flux-basedapproach to monitoring the water quality of large rivers","interactions":[],"lastModifiedDate":"2012-03-12T17:20:20","indexId":"70024043","displayToPublicDate":"2001-01-01T00:00:00","publicationYear":"2001","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1924,"text":"Hydrological Processes","active":true,"publicationSubtype":{"id":10}},"title":"The national stream quality accounting network: A flux-basedapproach to monitoring the water quality of large rivers","docAbstract":"Estimating the annual mass flux at a network of fixed stations is one approach to characterizing water quality of large rivers. The interpretive context provided by annual flux includes identifying source and sink areas for constituents and estimating the loadings to receiving waters, such as reservoirs or the ocean. Since 1995, the US Geological Survey's National Stream Quality Accounting Network (NASQAN) has employed this approach at a network of 39 stations in four of the largest river basins of the USA: The Mississippi, the Columbia, the Colorado and the Rio Grande. In this paper, the design of NASQAN is described and its effectiveness at characterizing the water quality of these rivers is evaluated using data from the first 3 years of operation. A broad range of constituents was measured by NASQAN, including trace organic and inorganic chemicals, major ions, sediment and nutrients. Where possible, a regression model relating concentration to discharge and season was used to interpolate between chemical observations for flux estimation. For water-quality network design, the most important finding from NASQAN was the importance of having a specific objective (that is, estimating annual mass flux) and, from that, an explicitly stated data analysis strategy, namely the use of regression models to interpolate between observations. The use of such models aided in the design of sampling strategy and provided a context for data review. The regression models essentially form null hypotheses for concentration variation that can be evaluated by the observed data. The feedback between network operation and data collection established by the hypothesis tests places the water-quality network on a firm scientific footing.","largerWorkType":{"id":2,"text":"Article"},"largerWorkTitle":"Hydrological Processes","largerWorkSubtype":{"id":10,"text":"Journal Article"},"language":"English","doi":"10.1002/hyp.205","issn":"08856087","usgsCitation":"Hooper, R.P., Aulenbach, B., and Kelly, V., 2001, The national stream quality accounting network: A flux-basedapproach to monitoring the water quality of large rivers: Hydrological Processes, v. 15, no. 7, p. 1089-1106, https://doi.org/10.1002/hyp.205.","startPage":"1089","endPage":"1106","numberOfPages":"18","costCenters":[],"links":[{"id":207041,"rank":9999,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.1002/hyp.205"},{"id":231600,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"15","issue":"7","noUsgsAuthors":false,"publicationDate":"2001-05-25","publicationStatus":"PW","scienceBaseUri":"505badfbe4b08c986b323e9c","contributors":{"authors":[{"text":"Hooper, R. P.","contributorId":26321,"corporation":false,"usgs":true,"family":"Hooper","given":"R.","email":"","middleInitial":"P.","affiliations":[],"preferred":false,"id":399785,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Aulenbach, Brent T.","contributorId":62766,"corporation":false,"usgs":true,"family":"Aulenbach","given":"Brent T.","affiliations":[],"preferred":false,"id":399786,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Kelly, V.J.","contributorId":14009,"corporation":false,"usgs":true,"family":"Kelly","given":"V.J.","email":"","affiliations":[],"preferred":false,"id":399784,"contributorType":{"id":1,"text":"Authors"},"rank":3}]}}
,{"id":70024009,"text":"70024009 - 2001 - Chemical and isotopic evidence of nitrogen transformation in the Mississippi River, 1997-98","interactions":[],"lastModifiedDate":"2018-12-03T10:10:10","indexId":"70024009","displayToPublicDate":"2001-01-01T00:00:00","publicationYear":"2001","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1924,"text":"Hydrological Processes","active":true,"publicationSubtype":{"id":10}},"title":"Chemical and isotopic evidence of nitrogen transformation in the Mississippi River, 1997-98","docAbstract":"<p>Nitrate (NO3) and other nutrients discharged by the Mississippi River are suspected of causing a zone of depleted dissolved oxygen (hypoxic zone) in the Gulf of Mexico each summer. The hypoxic zone may have an adverse affect on aquatic life and commercial fisheries. The amount of NO3 delivered by the Mississippi River to the Gulf of Mexico is well documented, but the relative contributions of different sources of NO3, and the magnitude of subsequent in-stream transformations of NO3, are not well understood. Forty-two water samples collected in 1997 and 1998 at eight stations located either on the Mississippi River or its major tributaries were analysed for NO3, total nitrogen (N), atrazine, chloride concentrations and NO3 stable isotopes (δ15N and δ18O). These data are used to assess the magnitude and nature of in-stream N transformation and to determine if the δ15N and δ18O of NO3 provide information about NO3 sources and transformation processes in a large river system (drainage area 2 900 000 km2) that would otherwise be unavailable using concentration and discharge data alone. Results from 42 samples indicate that the δ15N and δ18O ratios between sites on the Mississippi River and its tributaries are somewhat distinctive, and vary with season and discharge rate. Of particular interest are two nearly Lagrangian sample sets, in which samples from the Mississippi River at St Francisville, LA, are compared with samples collected from the Ohio River at Grand Chain, II, and the Mississippi River at Thebes, IL. In both Lagrangian sets, mass-balance calculations indicate only a small amount of in-stream N loss. The stable isotope data from the samples suggest that in-stream N assimilation and not denitrification accounts for most of the N loss in the lower Mississippi River during the spring and early summer months.</p>","language":"English","publisher":"Wiley","doi":"10.1002/hyp.214","issn":"08856087","usgsCitation":"Battaglin, W.A., Kendall, C., Chang, C.C., Silva, S.R., and Campbell, K., 2001, Chemical and isotopic evidence of nitrogen transformation in the Mississippi River, 1997-98: Hydrological Processes, v. 15, no. 7, p. 1285-1300, https://doi.org/10.1002/hyp.214.","productDescription":"16 p.","startPage":"1285","endPage":"1300","costCenters":[{"id":191,"text":"Colorado Water Science Center","active":true,"usgs":true},{"id":589,"text":"Toxic Substances Hydrology Program","active":true,"usgs":true}],"links":[{"id":207092,"rank":9999,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.1002/hyp.214"},{"id":231711,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"country":"United States","otherGeospatial":"Mississippi River","volume":"15","issue":"7","noUsgsAuthors":false,"publicationDate":"2001-05-25","publicationStatus":"PW","scienceBaseUri":"5059f546e4b0c8380cd4c14a","contributors":{"authors":[{"text":"Battaglin, William A. 0000-0001-7287-7096 wbattagl@usgs.gov","orcid":"https://orcid.org/0000-0001-7287-7096","contributorId":1527,"corporation":false,"usgs":true,"family":"Battaglin","given":"William","email":"wbattagl@usgs.gov","middleInitial":"A.","affiliations":[{"id":191,"text":"Colorado Water Science Center","active":true,"usgs":true}],"preferred":true,"id":399673,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Kendall, Carol 0000-0002-0247-3405 ckendall@usgs.gov","orcid":"https://orcid.org/0000-0002-0247-3405","contributorId":1462,"corporation":false,"usgs":true,"family":"Kendall","given":"Carol","email":"ckendall@usgs.gov","affiliations":[{"id":438,"text":"National Research Program - Western Branch","active":true,"usgs":true}],"preferred":true,"id":399675,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Chang, Cecily C.Y.","contributorId":68032,"corporation":false,"usgs":true,"family":"Chang","given":"Cecily","email":"","middleInitial":"C.Y.","affiliations":[],"preferred":false,"id":399677,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Silva, Steven R. srsilva@usgs.gov","contributorId":3162,"corporation":false,"usgs":true,"family":"Silva","given":"Steven","email":"srsilva@usgs.gov","middleInitial":"R.","affiliations":[{"id":438,"text":"National Research Program - Western Branch","active":true,"usgs":true}],"preferred":true,"id":399674,"contributorType":{"id":1,"text":"Authors"},"rank":4},{"text":"Campbell, K.","contributorId":63351,"corporation":false,"usgs":false,"family":"Campbell","given":"K.","affiliations":[{"id":47665,"text":"St. Anthony Falls Laboratory, University of Minnesota, Minneapolis, MN, USA","active":true,"usgs":false}],"preferred":false,"id":399676,"contributorType":{"id":1,"text":"Authors"},"rank":5}]}}
,{"id":70023234,"text":"70023234 - 2001 - High CO2 emissions through porous media: Transport mechanisms and implications for flux measurement and fractionation","interactions":[],"lastModifiedDate":"2018-12-03T10:12:45","indexId":"70023234","displayToPublicDate":"2001-01-01T00:00:00","publicationYear":"2001","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1213,"text":"Chemical Geology","active":true,"publicationSubtype":{"id":10}},"title":"High CO2 emissions through porous media: Transport mechanisms and implications for flux measurement and fractionation","docAbstract":"<div id=\"abstracts\" class=\"Abstracts\"><div id=\"aep-abstract-id18\" class=\"abstract author\"><div id=\"aep-abstract-sec-id19\"><p id=\"simple-para.0075\">Diffuse emissions of CO<sub>2</sub><span>&nbsp;</span>are known to be large around some volcanoes and hydrothermal areas. Accumulation-chamber measurements of CO<sub>2</sub><span>&nbsp;</span>flux are increasingly used to estimate the total magmatic or metamorphic CO<sub>2</sub><span>&nbsp;</span>released from such areas. To assess the performance of accumulation chamber systems at fluxes one to three orders of magnitude higher than normally encountered in soil respiration studies, a test system was constructed in the laboratory where known fluxes could be maintained through dry sand. Steady-state gas concentration profiles and fractionation effects observed in the 30-cm sand column nearly match those predicted by the Stefan-Maxwell equations, indicating that the test system was functioning successfully as a uniform porous medium. Eight groups of investigators tested their accumulation chamber equipment, all configured with continuous infrared gas analyzers (IRGA), in this system. Over a flux range of ∼200–12,000 g m<sup>−2</sup>day<sup>−1</sup>, 90% of their 203 flux measurements were 0–25% lower than the imposed flux with a mean difference of −12.5%. Although this difference would seem to be within the range of acceptability for many geologic investigations, some potential sources for larger errors were discovered. A steady-state pressure gradient of −20 Pa/m was measured in the sand column at a flux of 11,200 g m<sup>−2</sup><span>&nbsp;</span>day<sup>−1</sup>. The derived permeability (50 darcies) was used in the dusty-gas model (DGM) of transport to quantify various diffusive and viscous flux components. These calculations were used to demonstrate that accumulation chambers, in addition to reducing the underlying diffusive gradient, severely disrupt the steady-state pressure gradient. The resultant diversion of the net gas flow is probably responsible for the systematically low flux measurements. It was also shown that the fractionating effects of a viscous CO<sub>2</sub><span>&nbsp;</span>efflux against a diffusive influx of air will have a major impact on some important geochemical indicators, such as N<sub>2</sub>/Ar,<span>&nbsp;</span><i>δ</i><sup>15</sup>N–N<sub>2</sub>, and<span>&nbsp;</span><sup>4</sup>He/<sup>22</sup>Ne.</p></div></div></div>","language":"English","publisher":"Elsevier","doi":"10.1016/S0009-2541(00)00379-X","issn":"00092541","usgsCitation":"Evans, W.C., Sorey, M., Kennedy, B.M., Stonestrom, D.A., Rogie, J., and Shuster, D., 2001, High CO2 emissions through porous media: Transport mechanisms and implications for flux measurement and fractionation: Chemical Geology, v. 177, no. 1-2, p. 15-29, https://doi.org/10.1016/S0009-2541(00)00379-X.","productDescription":"15 p.","startPage":"15","endPage":"29","costCenters":[{"id":589,"text":"Toxic Substances Hydrology Program","active":true,"usgs":true}],"links":[{"id":232677,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"},{"id":207595,"rank":9999,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.1016/S0009-2541(00)00379-X"}],"volume":"177","issue":"1-2","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505a30a8e4b0c8380cd5d82e","contributors":{"authors":[{"text":"Evans, William C.","contributorId":104903,"corporation":false,"usgs":true,"family":"Evans","given":"William","email":"","middleInitial":"C.","affiliations":[],"preferred":false,"id":396953,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Sorey, M.L.","contributorId":73185,"corporation":false,"usgs":true,"family":"Sorey","given":"M.L.","affiliations":[],"preferred":false,"id":396950,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Kennedy, B. M.","contributorId":97638,"corporation":false,"usgs":true,"family":"Kennedy","given":"B.","email":"","middleInitial":"M.","affiliations":[],"preferred":false,"id":396952,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"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":396951,"contributorType":{"id":1,"text":"Authors"},"rank":4},{"text":"Rogie, J.D.","contributorId":63571,"corporation":false,"usgs":true,"family":"Rogie","given":"J.D.","affiliations":[],"preferred":false,"id":396949,"contributorType":{"id":1,"text":"Authors"},"rank":5},{"text":"Shuster, D.L.","contributorId":14096,"corporation":false,"usgs":true,"family":"Shuster","given":"D.L.","email":"","affiliations":[],"preferred":false,"id":396948,"contributorType":{"id":1,"text":"Authors"},"rank":6}]}}
,{"id":70023979,"text":"70023979 - 2001 - Estimating suspended sediment and trace element fluxes in large river basins: Methodological considerations as applied to the NASQAN programme","interactions":[],"lastModifiedDate":"2012-03-12T17:20:02","indexId":"70023979","displayToPublicDate":"2001-01-01T00:00:00","publicationYear":"2001","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1924,"text":"Hydrological Processes","active":true,"publicationSubtype":{"id":10}},"title":"Estimating suspended sediment and trace element fluxes in large river basins: Methodological considerations as applied to the NASQAN programme","docAbstract":"In 1994, the NASQAN (National Stream Quality Accounting Network) programme was redesigned as a flux-based water-quality monitoring network for the Mississippi, Columbia, Colorado, and Rio Grande Basins. As the new programme represented a departure from the original, new sampling, processing, analytical, and data handling procedures had to be selected/developed to provide data on discharge, suspended sediment concentration, and the concentrations of suspended sediment and dissolved trace elements. Annual suspended sediment fluxes were estimated by summing daily instantaneous fluxes based on predicted suspended sediment concentrations derived from discharge-based log-log regression (rating-curve) models. The models were developed using both historical and current site-specific discharge and suspended sediment concentrations. Errors using this approach typically are less than ?? 10% for the 3-year reporting period; however, the magnitude of the errors increases substantially for temporal spans shorter than 1 year. Total, rather than total-recoverable, suspended sediment-associated trace element concentrations were determined by direct analysis of material dewatered from large-volume whole-water samples. Site-specific intra- and inter-annual suspended sediment-associated chemical variations were less (typically by no more than a factor of two) than those for either discharge or suspended sediment concentrations (usually more than 10-fold). The concentrations, hence the annual fluxes, for suspended sediment-associated phosphorus and organic carbon, determined by direct analyses, were higher than those determined using a more traditional paired, whole-water/filtered-water approach (by factors ranging from 1.5- to 10-fold). This may be important for such issues as eutrophication and coastal productivity. Filtered water-associated (dissolved) trace element concentrations were markedly lower than those determined during the historical NASQAN programme; many were below their respective detection limits. This resulted from the use of clean sampling, processing, and analytical protocols. Hence, the fluxes for filtered water-associated (dissolved) Ag, Pb, Co, V, Be, Sb, and Se, as well as the total (filtered water plus suspended sediment-associated) fluxes for these constituents, could not be estimated.","largerWorkType":{"id":2,"text":"Article"},"largerWorkTitle":"Hydrological Processes","largerWorkSubtype":{"id":10,"text":"Journal Article"},"language":"English","doi":"10.1002/hyp.206","issn":"08856087","usgsCitation":"Horowitz, A.J., Elrick, K.A., and Smith, J., 2001, Estimating suspended sediment and trace element fluxes in large river basins: Methodological considerations as applied to the NASQAN programme: Hydrological Processes, v. 15, no. 7, p. 1107-1132, https://doi.org/10.1002/hyp.206.","startPage":"1107","endPage":"1132","numberOfPages":"26","costCenters":[],"links":[{"id":207166,"rank":9999,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.1002/hyp.206"},{"id":231865,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"15","issue":"7","noUsgsAuthors":false,"publicationDate":"2001-05-25","publicationStatus":"PW","scienceBaseUri":"505a0b4fe4b0c8380cd52684","contributors":{"authors":[{"text":"Horowitz, A. J.","contributorId":102066,"corporation":false,"usgs":true,"family":"Horowitz","given":"A.","email":"","middleInitial":"J.","affiliations":[],"preferred":false,"id":399580,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Elrick, K. A.","contributorId":98731,"corporation":false,"usgs":true,"family":"Elrick","given":"K.","email":"","middleInitial":"A.","affiliations":[],"preferred":false,"id":399579,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Smith, J.J.","contributorId":106175,"corporation":false,"usgs":true,"family":"Smith","given":"J.J.","email":"","affiliations":[],"preferred":false,"id":399581,"contributorType":{"id":1,"text":"Authors"},"rank":3}]}}
,{"id":70023235,"text":"70023235 - 2001 - Eddy covariance measurement of CO2 flux to the atmosphere from a area of high volcanogenic emissions, Mammoth Mountain, California","interactions":[],"lastModifiedDate":"2018-11-30T05:55:07","indexId":"70023235","displayToPublicDate":"2001-01-01T00:00:00","publicationYear":"2001","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1213,"text":"Chemical Geology","active":true,"publicationSubtype":{"id":10}},"title":"Eddy covariance measurement of CO2 flux to the atmosphere from a area of high volcanogenic emissions, Mammoth Mountain, California","docAbstract":"<p><span>Three pilot studies were performed to assess application of the eddy covariance micrometeorological method in the measurement of carbon dioxide (CO</span><sub>2</sub><span>) flux of volcanic origin. The selected study area is one of high diffuse CO</span><sub>2</sub><span>&nbsp;emission on Mammoth Mountain, CA. Because terrain and source characteristics make this a complex setting for this type of measurement, added consideration was given to source area and upwind fetch. Footprint analysis suggests that the eddy covariance measurements were representative of an upwind elliptical source area (3.8×10</span><sup>3</sup><span>&nbsp;m</span><sup>2</sup><span>) which can vary with mean wind direction, surface roughness, and atmospheric stability. CO</span><sub>2</sub><span>&nbsp;flux averaged 8–16 mg m</span><sup>−2</sup><span>&nbsp;s</span><sup>−1</sup><span>&nbsp;(0.7–1.4 kg m</span><sup>−2</sup><span>day</span><sup>−1</sup><span>). Eddy covariance measurements of flux were compared with surface chamber measurements made in separate studies [Geophys. Res. Lett. 25 (1998a) 1947; EOS Trans. 79 (1998) F941.] and were found to be similar.</span></p>","language":"English","publisher":"Elsevier","doi":"10.1016/S0009-2541(00)00380-6","issn":"00092541","usgsCitation":"Anderson, D.E., and Farrar, C.D., 2001, Eddy covariance measurement of CO2 flux to the atmosphere from a area of high volcanogenic emissions, Mammoth Mountain, California: Chemical Geology, v. 177, no. 1-2, p. 31-42, https://doi.org/10.1016/S0009-2541(00)00380-6.","productDescription":"12 p.","startPage":"31","endPage":"42","costCenters":[{"id":154,"text":"California Water Science Center","active":true,"usgs":true},{"id":589,"text":"Toxic Substances Hydrology Program","active":true,"usgs":true}],"links":[{"id":232717,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"},{"id":207615,"rank":9999,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.1016/S0009-2541(00)00380-6"}],"volume":"177","issue":"1-2","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505a05a7e4b0c8380cd50ebd","contributors":{"authors":[{"text":"Anderson, Dean E. deander@usgs.gov","contributorId":662,"corporation":false,"usgs":true,"family":"Anderson","given":"Dean","email":"deander@usgs.gov","middleInitial":"E.","affiliations":[],"preferred":true,"id":396954,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Farrar, Christopher D. cdfarrar@usgs.gov","contributorId":1501,"corporation":false,"usgs":true,"family":"Farrar","given":"Christopher","email":"cdfarrar@usgs.gov","middleInitial":"D.","affiliations":[],"preferred":true,"id":396955,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}}
,{"id":70023236,"text":"70023236 - 2001 - Nitrogen input to the Gulf of Mexico","interactions":[],"lastModifiedDate":"2020-09-25T18:16:02.119947","indexId":"70023236","displayToPublicDate":"2001-01-01T00:00:00","publicationYear":"2001","noYear":false,"publicationType":{"id":24,"text":"Conference Paper"},"publicationSubtype":{"id":19,"text":"Conference Paper"},"title":"Nitrogen input to the Gulf of Mexico","docAbstract":"Historical streamflow and concentration data were used in regression models to estimate the annual flux of nitrogen (N) to the Gulf of Mexico and to determine where the nitrogen originates within the Mississippi Basin. Results show that for 1980-1996 the mean annual total N flux to the Gulf of Mexico was 1 568 000 t yr-1. The flux was about 61% nitrate N, 37% organic N, and 2% ammonium N. The flux of nitrate N to the Gulf has approximately tripled in the last 30 years with most of the increase occurring between 1970 and 1983. The mean annual N flux has changed little since the early 1980s, but large year-to-year variations in N flux occur because of variations in precipitation. During wet years the N flux can increase by 50% or more due to flushing of nitrate N that has accumulated in the soils and unsaturated zones in the basin. The principal source areas of N are basins in southern Minnesota, Iowa, Illinois, Indiana, and Ohio that drain agricultural land. Basins in this region yield 1500 to more than 3100 kg N km-2 yr-1 to streams, several times the N yield of basins outside this region.","language":"English","publisher":"Wiley","doi":"10.2134/jeq2001.302329x","issn":"00472425","usgsCitation":"Goolsby, D.A., Battaglin, W., Aulenbach, B., and Hooper, R.P., 2001, Nitrogen input to the Gulf of Mexico, v. 30, no. 2, p. 329-336, https://doi.org/10.2134/jeq2001.302329x.","productDescription":"8 p.","startPage":"329","endPage":"336","numberOfPages":"8","costCenters":[{"id":589,"text":"Toxic Substances Hydrology Program","active":true,"usgs":true}],"links":[{"id":232718,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"country":"United States","otherGeospatial":"Mississippi–Atchafalaya River basin","geographicExtents":"{\n  \"type\": \"FeatureCollection\",\n  \"features\": [\n    {\n      \"type\": \"Feature\",\n      \"properties\": {},\n      \"geometry\": {\n        \"type\": \"Polygon\",\n        \"coordinates\": [\n          [\n            [\n              -92.28515625,\n              46.255846818480315\n            ],\n            [\n              -93.955078125,\n              46.98025235521883\n            ],\n            [\n              -98.173828125,\n              48.3416461723746\n            ],\n            [\n              -101.6015625,\n              48.22467264956519\n            ],\n            [\n              -102.12890625,\n              46.01222384063236\n            ],\n            [\n              -100.107421875,\n              42.94033923363181\n            ],\n            [\n              -97.03125,\n              41.44272637767212\n            ],\n            [\n              -94.306640625,\n              38.61687046392973\n            ],\n            [\n              -93.515625,\n              34.45221847282654\n            ],\n            [\n              -94.39453125,\n              30.221101852485987\n            ],\n            [\n              -92.46093749999999,\n              28.844673680771795\n            ],\n            [\n              -89.6484375,\n              28.844673680771795\n            ],\n            [\n              -88.330078125,\n              30.14512718337613\n            ],\n            [\n              -88.505859375,\n              34.23451236236987\n            ],\n            [\n              -87.451171875,\n              39.57182223734374\n            ],\n            [\n              -85.341796875,\n              39.30029918615029\n            ],\n            [\n              -78.75,\n              39.57182223734374\n            ],\n            [\n              -75.234375,\n              42.09822241118974\n            ],\n            [\n              -75.41015624999999,\n              44.59046718130883\n            ],\n            [\n              -79.1015625,\n              42.94033923363181\n            ],\n            [\n              -82.6171875,\n              41.44272637767212\n            ],\n            [\n              -87.5390625,\n              41.77131167976407\n            ],\n            [\n              -89.296875,\n              43.644025847699496\n            ],\n            [\n              -91.318359375,\n              45.9511496866914\n            ],\n            [\n              -92.28515625,\n              46.255846818480315\n            ]\n          ]\n        ]\n      }\n    }\n  ]\n}","volume":"30","issue":"2","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505a66e2e4b0c8380cd73051","contributors":{"authors":[{"text":"Goolsby, D. A.","contributorId":50508,"corporation":false,"usgs":true,"family":"Goolsby","given":"D.","email":"","middleInitial":"A.","affiliations":[],"preferred":false,"id":396958,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Battaglin, W.A.","contributorId":16376,"corporation":false,"usgs":true,"family":"Battaglin","given":"W.A.","email":"","affiliations":[],"preferred":false,"id":396956,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Aulenbach, Brent T.","contributorId":62766,"corporation":false,"usgs":true,"family":"Aulenbach","given":"Brent T.","affiliations":[],"preferred":false,"id":396959,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Hooper, R. P.","contributorId":26321,"corporation":false,"usgs":true,"family":"Hooper","given":"R.","email":"","middleInitial":"P.","affiliations":[],"preferred":false,"id":396957,"contributorType":{"id":1,"text":"Authors"},"rank":4}]}}
,{"id":70023978,"text":"70023978 - 2001 - Anthropogenic organic matter in the Great Marsh of the Indiana Dunes National Lakeshore and its implications","interactions":[],"lastModifiedDate":"2012-03-12T17:20:02","indexId":"70023978","displayToPublicDate":"2001-01-01T00:00:00","publicationYear":"2001","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":2033,"text":"International Journal of Coal Geology","active":true,"publicationSubtype":{"id":10}},"title":"Anthropogenic organic matter in the Great Marsh of the Indiana Dunes National Lakeshore and its implications","docAbstract":"Cores from the Great Marsh area of the Indiana Dunes National Lakeshore were examined in order to document variations in concentration, type and size of anthropogenic organic matter (AnOM-coal, coke, etc.) and discuss their relationship to the concentration of such trace elements as Pb, Zn, and Mn in the near-surface sediment section. The results indicate that the first appearance of AnOM corresponds to the onset of industrialization in the area. There is also a general relationship between the occurrence of AnOM and Zn, Pb, and Mn. Trace metals were likely transported from the industrial sites to the area of their deposition as sulfur-bearing coatings on small anthropogenic particles. After deposition, these sulfur-bearing compounds reacted with organic matter within the marsh. As a result of bacterial reduction, the pyrite was produced, as suggested by a close relationship between the pyrite and AnOM. Distance from the industrial complex upwind as well as local hydrologic conditions are among the major factors controlling distribution of AnOM and trace elements. At the same distance from the source, types and sizes of AnOM are influenced by the duration and frequency of flooding. ?? 2001 Elsevier Science B.V. All rights reserved.","largerWorkType":{"id":2,"text":"Article"},"largerWorkTitle":"International Journal of Coal Geology","largerWorkSubtype":{"id":10,"text":"Journal Article"},"language":"English","doi":"10.1016/S0166-5162(01)00016-7","issn":"01665162","usgsCitation":"Mastalerz, M., Souch, C., Filippelli, G.M., Dollar, N., and Perkins, S., 2001, Anthropogenic organic matter in the Great Marsh of the Indiana Dunes National Lakeshore and its implications: International Journal of Coal Geology, v. 46, no. 2-4, p. 157-177, https://doi.org/10.1016/S0166-5162(01)00016-7.","startPage":"157","endPage":"177","numberOfPages":"21","costCenters":[],"links":[{"id":231827,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"},{"id":207148,"rank":9999,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.1016/S0166-5162(01)00016-7"}],"volume":"46","issue":"2-4","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"5059ec5be4b0c8380cd4920e","contributors":{"authors":[{"text":"Mastalerz, Maria","contributorId":78065,"corporation":false,"usgs":true,"family":"Mastalerz","given":"Maria","affiliations":[],"preferred":false,"id":399578,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Souch, C.","contributorId":46368,"corporation":false,"usgs":true,"family":"Souch","given":"C.","email":"","affiliations":[],"preferred":false,"id":399575,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Filippelli, G. M.","contributorId":64070,"corporation":false,"usgs":false,"family":"Filippelli","given":"G.","email":"","middleInitial":"M.","affiliations":[],"preferred":false,"id":399577,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Dollar, N.L.","contributorId":24635,"corporation":false,"usgs":true,"family":"Dollar","given":"N.L.","email":"","affiliations":[],"preferred":false,"id":399574,"contributorType":{"id":1,"text":"Authors"},"rank":4},{"text":"Perkins, S.M.","contributorId":63273,"corporation":false,"usgs":true,"family":"Perkins","given":"S.M.","email":"","affiliations":[],"preferred":false,"id":399576,"contributorType":{"id":1,"text":"Authors"},"rank":5}]}}
,{"id":70023302,"text":"70023302 - 2001 - Influence of reactive sulfide (AVS) and supplementary food on Ag, Cd and Zn bioaccumulation in the marine polychaete Neanthes arenaceodentata","interactions":[],"lastModifiedDate":"2018-12-03T08:55:15","indexId":"70023302","displayToPublicDate":"2001-01-01T00:00:00","publicationYear":"2001","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":"Influence of reactive sulfide (AVS) and supplementary food on Ag, Cd and Zn bioaccumulation in the marine polychaete Neanthes arenaceodentata","docAbstract":"A laboratory bioassay determined the relative contribution of various pathways of Ag, Cd and Zn bioaccumulation in the marine polychaete Neanthes arenaceodentata exposed to moderately contaminated sediments. Juvenile worms were exposed for 25 d to experimental sediments containing 5 different reactive sulfide (acid volatile sulfides, AVS) concentrations (1 to 30 ??mol g-1), but with constant Ag, Cd, and Zn concentrations of 0.1, 0.1 and 7 ??mol g-1, respectively. The sediments were supplemented with contaminated food (TetraMin??) containing 3 levels of Ag-Cd-Zn (uncontaminated, 1?? or 5??1 metal concentrations in the contaminated sediment). The results suggest that bioaccumulation of Ag, Cd and Zn in the worms occurred predominantly from ingestion of contaminated sediments and contaminated supplementary food. AVS or dissolved metals (in porewater and overlying water) had a minor effect on bioaccumulation of the 3 metals in most of the treatments. The contribution to uptake from the dissolved source was most important in the most oxic sediments, with maximum contributions of 8% for Ag, 30% for Cd and 20% for Zn bioaccumulation. Sediment bioassays where uncontaminated supplemental food is added could seriously underestimate metal exposures in an equilibrated system; N. arenaceodentata feeding on uncontaminated food would be exposed to 40-60% less metal than if the food source was equilibrated (as occurs in nature). Overall, the results show that pathways of metal exposure are dynamically linked in contaminated sediments and shift as external geochemical characteristics and internal biological attributes vary.","language":"English","publisher":"Inter-Research","doi":"10.3354/meps216129","issn":"01718630","usgsCitation":"Lee, J., Lee, B., Yoo, H., Koh, C., and Luoma, S., 2001, Influence of reactive sulfide (AVS) and supplementary food on Ag, Cd and Zn bioaccumulation in the marine polychaete Neanthes arenaceodentata: Marine Ecology Progress Series, v. 216, p. 129-140, https://doi.org/10.3354/meps216129.","productDescription":"12 p.","startPage":"129","endPage":"140","costCenters":[{"id":589,"text":"Toxic Substances Hydrology Program","active":true,"usgs":true}],"links":[{"id":478950,"rank":1,"type":{"id":40,"text":"Open Access Publisher Index Page"},"url":"https://doi.org/10.3354/meps216129","text":"Publisher Index Page"},{"id":232519,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"216","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505a3b6de4b0c8380cd62513","contributors":{"authors":[{"text":"Lee, J.-S.","contributorId":15787,"corporation":false,"usgs":true,"family":"Lee","given":"J.-S.","email":"","affiliations":[],"preferred":false,"id":397204,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Lee, B.-G.","contributorId":11777,"corporation":false,"usgs":true,"family":"Lee","given":"B.-G.","email":"","affiliations":[],"preferred":false,"id":397203,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Yoo, H.","contributorId":46725,"corporation":false,"usgs":true,"family":"Yoo","given":"H.","email":"","affiliations":[],"preferred":false,"id":397205,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Koh, C.-H.","contributorId":9797,"corporation":false,"usgs":true,"family":"Koh","given":"C.-H.","email":"","affiliations":[],"preferred":false,"id":397202,"contributorType":{"id":1,"text":"Authors"},"rank":4},{"text":"Luoma, S. N.","contributorId":86353,"corporation":false,"usgs":true,"family":"Luoma","given":"S. N.","affiliations":[],"preferred":false,"id":397206,"contributorType":{"id":1,"text":"Authors"},"rank":5}]}}
,{"id":70023340,"text":"70023340 - 2001 - Sulfate-reducing bacteria release barium and radium from naturally occurring radioactive material in oil-field barite","interactions":[],"lastModifiedDate":"2018-11-30T06:40:35","indexId":"70023340","displayToPublicDate":"2001-01-01T00:00:00","publicationYear":"2001","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1800,"text":"Geomicrobiology Journal","active":true,"publicationSubtype":{"id":10}},"title":"Sulfate-reducing bacteria release barium and radium from naturally occurring radioactive material in oil-field barite","docAbstract":"Scale and sludge deposits formed during oil production can contain elevated levels of Ra, often coprecipitated with barium sulfate (barite). The potential for sulfate-reducing bacteria to release 226 Ra and Ba (a Ra analog) from oil-field barite was evaluated. The concentration of dissolved Ba increased when samples containing pipe scale, tank sludge, or oil-field brine pond sediment were incubated with sulfate-reducing bacteria Desulfovibrio sp., Str LZKI, isolated from an oil-field brine pond. However, Ba release was not stoichiometric with sulfide production in oil-field samples, and <0.1% of the Ba was released. Potential for the release of 226Ra was demonstrated, and the 226 Ra release associated with sulfate-reducing activity was predictable from the amount of Ba released. As with Ba, only a fraction of the 226Ra expected from the amount of sulfide produced was released, and most of the Ra remained associated with the solid material.","language":"English","publisher":"Taylor & Francis","doi":"10.1080/01490450120549","issn":"01490451","usgsCitation":"Phillips, E.J., Landa, E.R., Kraemer, T., and Zielinski, R., 2001, Sulfate-reducing bacteria release barium and radium from naturally occurring radioactive material in oil-field barite: Geomicrobiology Journal, v. 18, no. 2, p. 167-182, https://doi.org/10.1080/01490450120549.","productDescription":"16 p.","startPage":"167","endPage":"182","costCenters":[{"id":589,"text":"Toxic Substances Hydrology Program","active":true,"usgs":true}],"links":[{"id":232478,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"18","issue":"2","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505b9dc3e4b08c986b31da71","contributors":{"authors":[{"text":"Phillips, Elizabeth J.P.","contributorId":37475,"corporation":false,"usgs":true,"family":"Phillips","given":"Elizabeth","middleInitial":"J.P.","affiliations":[],"preferred":false,"id":397312,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Landa, E. R.","contributorId":100002,"corporation":false,"usgs":true,"family":"Landa","given":"E.","email":"","middleInitial":"R.","affiliations":[],"preferred":false,"id":397314,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Kraemer, T.","contributorId":90040,"corporation":false,"usgs":true,"family":"Kraemer","given":"T.","affiliations":[],"preferred":false,"id":397313,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Zielinski, R. 0000-0002-4047-5129","orcid":"https://orcid.org/0000-0002-4047-5129","contributorId":7046,"corporation":false,"usgs":true,"family":"Zielinski","given":"R.","affiliations":[{"id":164,"text":"Central Energy Resources Science Center","active":true,"usgs":true}],"preferred":false,"id":397311,"contributorType":{"id":1,"text":"Authors"},"rank":4}]}}
,{"id":70023343,"text":"70023343 - 2001 - Timescales for nitrate contamination of spring waters, northern Florida, USA","interactions":[],"lastModifiedDate":"2020-02-26T19:38:10","indexId":"70023343","displayToPublicDate":"2001-01-01T00:00:00","publicationYear":"2001","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1213,"text":"Chemical Geology","active":true,"publicationSubtype":{"id":10}},"title":"Timescales for nitrate contamination of spring waters, northern Florida, USA","docAbstract":"<p><span>Residence times of groundwater, discharging from springs in the middle Suwannee River Basin, were estimated using chlorofluorocarbons (CFCs), tritium (</span><sup>3</sup><span>H), and tritium/helium-3 (</span><sup>3</sup><span>H/</span><sup>3</sup><span>He) age-dating methods to assess the chronology of nitrate contamination of spring waters in northern Florida. During base-flow conditions for the Suwannee River in 1997–1999, 17 water samples were collected from 12 first, second, and third magnitude springs discharging groundwater from the Upper Floridan aquifer. Extending age-dating techniques, using transient tracers to spring waters in complex karst systems, required an assessment of several models [piston-flow (PFM), exponential mixing (EMM), and binary-mixing (BMM)] to account for different distributions of groundwater age. Multi-tracer analyses of four springs yielded generally concordant PFM ages of around 20±2 years from CFC-12, CFC-113, </span><sup>3</sup><span>H, and </span><sup>3</sup><span>He, with evidence of partial CFC-11 degradation. The EMM gave a reasonable fit to CFC-113, CFC-12, and </span><sup>3</sup><span>H data, but did not reproduce the observed </span><sup>3</sup><span>He concentrations or </span><sup>3</sup><span>H/</span><sup>3</sup><span>He ratios, nor did a combination PFM–EMM. The BMM could reproduce most of the multi-tracer data set only if both endmembers had </span><sup>3</sup><span>H concentrations not much different from modern values. CFC analyses of 14 additional springs yielded apparent PFM ages from about 10 to 20 years from CFC-113, with evidence of partial CFC-11 degradation and variable CFC-12 contamination. While it is not conclusive, with respect to the age distribution within each spring, the data indicate that the average residence times were in the order of 10–20 years and were roughly proportional to spring magnitude. Applying similar models to recharge and discharge of nitrate based on historical nitrogen loading data yielded contrasting trends for Suwanee County and Lafayette County. In Suwanee County, spring nitrate trends and nitrogen isotope data were consistent with a peak in fertilizer input in the 1970s and a relatively high overall ratio of artificial fertilizer/manure; whereas in Lafayette County, spring nitrate trends and nitrogen isotope data were consistent with a more monotonic increase in fertilizer input and relatively low overall ratio of artificial fertilizer/manure. The combined results of this study indicate that the nitrate concentrations of springs in the Suwannee River basin have responded to increased nitrogen loads from various sources in the watersheds over the last few decades; however, the responses have been subdued and delayed because the average residence time of groundwater discharging from springs are in the order of decades.</span></p>","language":"English","publisher":"Elsevier","doi":"10.1016/S0009-2541(01)00321-7","issn":"00092541","usgsCitation":"Katz, B., Böhlke, J., and Hornsby, H., 2001, Timescales for nitrate contamination of spring waters, northern Florida, USA: Chemical Geology, v. 179, no. 1-4, p. 167-186, https://doi.org/10.1016/S0009-2541(01)00321-7.","productDescription":"20 p.","startPage":"167","endPage":"186","costCenters":[{"id":589,"text":"Toxic Substances Hydrology Program","active":true,"usgs":true}],"links":[{"id":232521,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"},{"id":207515,"rank":9999,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.1016/S0009-2541(01)00321-7"}],"country":"United States","state":"Florida","geographicExtents":"{\n  \"type\": \"FeatureCollection\",\n  \"features\": [\n    {\n      \"type\": \"Feature\",\n      \"properties\": {},\n      \"geometry\": {\n        \"type\": \"Polygon\",\n        \"coordinates\": [\n          [\n            [\n              -87.36328125,\n              30.334953881988564\n            ],\n            [\n              -86.98974609375,\n              30.278044377800153\n            ],\n            [\n              -86.2646484375,\n              30.240086360983426\n            ],\n            [\n              -85.6494140625,\n              29.935895213372444\n            ],\n            [\n              -85.45166015624999,\n              29.592565403314087\n            ],\n            [\n              -85.0341796875,\n              29.592565403314087\n            ],\n            [\n              -84.19921875,\n              29.783449456820605\n            ],\n            [\n              -84.17724609375,\n              29.99300228455108\n            ],\n            [\n              -83.8916015625,\n              29.916852233070173\n            ],\n            [\n              -83.49609375,\n              29.477861195816843\n            ],\n            [\n              -83.03466796874999,\n              28.94086176940557\n            ],\n            [\n              -82.9248046875,\n              29.075375179558346\n            ],\n            [\n              -82.79296874999999,\n              28.671310915880834\n            ],\n            [\n              -80.79345703125,\n              28.825425374477224\n            ],\n            [\n              -81.2548828125,\n              29.6880527498568\n            ],\n            [\n              -81.45263671875,\n              30.732392734006083\n            ],\n            [\n              -82.02392578125,\n              30.86451022625836\n            ],\n            [\n              -82.0458984375,\n              30.637912028341123\n            ],\n            [\n              -84.83642578125,\n              30.789036751261136\n            ],\n            [\n              -85.0341796875,\n              31.052933985705163\n            ],\n            [\n              -87.64892578125,\n              31.034108344903512\n            ],\n            [\n              -87.36328125,\n              30.334953881988564\n            ]\n          ]\n        ]\n      }\n    }\n  ]\n}","volume":"179","issue":"1-4","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505bb3e2e4b08c986b32604a","contributors":{"authors":[{"text":"Katz, B. G.","contributorId":82702,"corporation":false,"usgs":true,"family":"Katz","given":"B. G.","affiliations":[],"preferred":false,"id":397322,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Böhlke, J.K. 0000-0001-5693-6455","orcid":"https://orcid.org/0000-0001-5693-6455","contributorId":96696,"corporation":false,"usgs":true,"family":"Böhlke","given":"J.K.","affiliations":[],"preferred":false,"id":397324,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Hornsby, H.D.","contributorId":91139,"corporation":false,"usgs":true,"family":"Hornsby","given":"H.D.","email":"","affiliations":[],"preferred":false,"id":397323,"contributorType":{"id":1,"text":"Authors"},"rank":3}]}}
,{"id":70023370,"text":"70023370 - 2001 - Laboratory and field evaluations of the LISST-100 instrument for suspended particle size determinations","interactions":[],"lastModifiedDate":"2018-12-03T08:59:02","indexId":"70023370","displayToPublicDate":"2001-01-01T00:00:00","publicationYear":"2001","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":2667,"text":"Marine Geology","active":true,"publicationSubtype":{"id":10}},"title":"Laboratory and field evaluations of the LISST-100 instrument for suspended particle size determinations","docAbstract":"<div id=\"abstracts\" class=\"Abstracts\"><div id=\"aep-abstract-id15\" class=\"abstract author\"><div id=\"aep-abstract-sec-id16\"><p id=\"simple-para0060\">Advances in technology have resulted in a new instrument that is designed for in-situ determination of particle size spectra. Such an instrument that can measure undisturbed particle size distributions is much needed for sediment transport studies. The LISST-100 (Laser In-Situ Scattering and Transmissometry) uses the principle of laser diffraction to obtain the size distribution and volume concentration of suspended material in 32 size classes logarithmically spaced between 1.25 and 250&nbsp;μm. This paper describes a laboratory evaluation of the ability of LISST-100 to determine particle sizes using suspensions of single size, artificial particles. Findings show the instrument is able to determine particle size to within about 10% with increasing error as particle size increases. The instrument determines volume (or mass) concentration using a volume conversion factor<span>&nbsp;</span><i>C</i><sub>v</sub>. This volume conversion factor is theoretically a constant. In the laboratory evaluation<span>&nbsp;</span><i>C</i><sub>v</sub><span>&nbsp;</span>is found to vary by a factor of about three over the particle size range between 5 and 200&nbsp;μm. Results from field studies in South San Francisco Bay show that values of mass concentration of suspended marine sediments estimated by LISST-100 agree favorably with estimates from optical backscatterance sensors if an appropriate value of<span>&nbsp;</span><i>C</i><sub>v</sub>, according to mean size, is used and the assumed average particle (aggregate) density is carefully chosen. Analyses of size distribution of suspended materials in South San Francisco Bay over multiple tide cycles suggest the likelihood of different sources of sediment because of different size characteristics during flood and ebb cycles.</p></div></div></div>","language":"English","publisher":"Elsevier","doi":"10.1016/S0025-3227(01)00137-2","issn":"00253227","usgsCitation":"Gartner, J.W., Cheng, R.T., Wang, P., and Richter, K., 2001, Laboratory and field evaluations of the LISST-100 instrument for suspended particle size determinations: Marine Geology, v. 175, no. 1-4, p. 199-219, https://doi.org/10.1016/S0025-3227(01)00137-2.","productDescription":"21 p.","startPage":"199","endPage":"219","costCenters":[{"id":589,"text":"Toxic Substances Hydrology Program","active":true,"usgs":true}],"links":[{"id":232362,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"},{"id":207424,"rank":9999,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.1016/S0025-3227(01)00137-2"}],"volume":"175","issue":"1-4","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505a40ffe4b0c8380cd65201","contributors":{"authors":[{"text":"Gartner, J. W.","contributorId":81903,"corporation":false,"usgs":false,"family":"Gartner","given":"J.","email":"","middleInitial":"W.","affiliations":[],"preferred":false,"id":397436,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Cheng, R. T.","contributorId":23138,"corporation":false,"usgs":false,"family":"Cheng","given":"R.","email":"","middleInitial":"T.","affiliations":[],"preferred":false,"id":397433,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Wang, P.-F.","contributorId":25311,"corporation":false,"usgs":true,"family":"Wang","given":"P.-F.","email":"","affiliations":[],"preferred":false,"id":397434,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Richter, K.","contributorId":72146,"corporation":false,"usgs":true,"family":"Richter","given":"K.","email":"","affiliations":[],"preferred":false,"id":397435,"contributorType":{"id":1,"text":"Authors"},"rank":4}]}}
,{"id":70023413,"text":"70023413 - 2001 - Regression models for estimating herbicide concentrations in U.S. streams from watershed characteristics","interactions":[],"lastModifiedDate":"2022-12-21T14:59:29.873017","indexId":"70023413","displayToPublicDate":"2001-01-01T00:00:00","publicationYear":"2001","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":2529,"text":"Journal of the American Water Resources Association","active":true,"publicationSubtype":{"id":10}},"title":"Regression models for estimating herbicide concentrations in U.S. streams from watershed characteristics","docAbstract":"Regression models were developed for estimating stream concentrations of the herbicides alachlor, atrazine, cyanazine, metolachlor, and trifluralin from use-intensity data and watershed characteristics. Concentrations were determined from samples collected from 45 streams throughout the United States during 1993 to 1995 as part of the U.S. Geological Survey's National Water-Quality Assessment (NAWQA). Separate regression models were developed for each of six percentiles (10th, 25th, 50th, 75th, 90th, 95th) of the annual distribution of stream concentrations and for the annual time-weighted mean concentration. Estimates for the individual percentiles can be combined to provide an estimate of the annual distribution of concentrations for a given stream. Agricultural use of the herbicide in the watershed was a significant predictor in nearly all of the models. Several hydrologic and soil parameters also were useful in explaining the variability in concentrations of herbicides among the streams. Most of the regression models developed for estimation of concentration percentiles and annual mean concentrations accounted for 50 percent to 90 percent of the variability among streams. Predicted concentrations were nearly always within an order of magnitude of the measured concentrations for the model-development streams, and predicted concentration distributions reasonably matched the actual distributions in most cases. Results from application of the models to streams not included in the model development data set are encouraging, but further validation of the regression approach described in this paper is needed.","language":"English","publisher":"American Water Resources Association","doi":"10.1111/j.1752-1688.2001.tb03644.x","issn":"1093474X","usgsCitation":"Larson, S., and Gilliom, R.J., 2001, Regression models for estimating herbicide concentrations in U.S. streams from watershed characteristics: Journal of the American Water Resources Association, v. 37, no. 5, p. 1349-1367, https://doi.org/10.1111/j.1752-1688.2001.tb03644.x.","productDescription":"19 p.","startPage":"1349","endPage":"1367","costCenters":[],"links":[{"id":232443,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"country":"United States","geographicExtents":"{\"type\":\"FeatureCollection\",\"features\":[{\"type\":\"Feature\",\"geometry\":{\"type\":\"MultiPolygon\",\"coordinates\":[[[[-66.28243,18.51476],[-65.7713,18.42668],[-65.591,18.22803],[-65.84716,17.97591],[-66.59993,17.98182],[-67.18416,17.94655],[-67.24243,18.37446],[-67.10068,18.5206],[-66.28243,18.51476]]],[[[-155.54211,19.08348],[-155.68817,18.91619],[-155.93665,19.05939],[-155.90806,19.33888],[-156.07347,19.70294],[-156.02368,19.81422],[-155.85008,19.97729],[-155.91907,20.17395],[-155.86108,20.26721],[-155.78505,20.2487],[-155.40214,20.07975],[-155.22452,19.99302],[-155.06226,19.8591],[-154.80741,19.50871],[-154.83147,19.45328],[-155.22217,19.23972],[-155.54211,19.08348]]],[[[-156.07926,20.64397],[-156.41445,20.57241],[-156.58673,20.783],[-156.70167,20.8643],[-156.71055,20.92676],[-156.61258,21.01249],[-156.25711,20.91745],[-155.99566,20.76404],[-156.07926,20.64397]]],[[[-156.75824,21.17684],[-156.78933,21.06873],[-157.32521,21.09777],[-157.25027,21.21958],[-156.75824,21.17684]]],[[[-157.65283,21.32217],[-157.70703,21.26442],[-157.7786,21.27729],[-158.12667,21.31244],[-158.2538,21.53919],[-158.29265,21.57912],[-158.0252,21.71696],[-157.94161,21.65272],[-157.65283,21.32217]]],[[[-159.34512,21.982],[-159.46372,21.88299],[-159.80051,22.06533],[-159.74877,22.1382],[-159.5962,22.23618],[-159.36569,22.21494],[-159.34512,21.982]]],[[[-94.81758,49.38905],[-94.64,48.84],[-94.32914,48.67074],[-93.63087,48.60926],[-92.61,48.45],[-91.64,48.14],[-90.83,48.27],[-89.6,48.01],[-89.27292,48.01981],[-88.37811,48.30292],[-87.43979,47.94],[-86.46199,47.55334],[-85.65236,47.22022],[-84.87608,46.90008],[-84.77924,46.6371],[-84.54375,46.53868],[-84.6049,46.4396],[-84.3367,46.40877],[-84.14212,46.51223],[-84.09185,46.27542],[-83.89077,46.11693],[-83.61613,46.11693],[-83.46955,45.99469],[-83.59285,45.81689],[-82.55092,45.34752],[-82.33776,44.44],[-82.13764,43.57109],[-82.43,42.98],[-82.9,42.43],[-83.12,42.08],[-83.142,41.97568],[-83.02981,41.8328],[-82.69009,41.67511],[-82.43928,41.67511],[-81.27775,42.20903],[-80.24745,42.3662],[-78.93936,42.86361],[-78.92,42.965],[-79.01,43.27],[-79.17167,43.46634],[-78.72028,43.62509],[-77.73789,43.62906],[-76.82003,43.62878],[-76.5,44.01846],[-76.375,44.09631],[-75.31821,44.81645],[-74.867,45.00048],[-73.34783,45.00738],[-71.50506,45.0082],[-71.405,45.255],[-71.08482,45.30524],[-70.66,45.46],[-70.305,45.915],[-69.99997,46.69307],[-69.23722,47.44778],[-68.905,47.185],[-68.23444,47.35486],[-67.79046,47.06636],[-67.79134,45.70281],[-67.13741,45.13753],[-66.96466,44.8097],[-68.03252,44.3252],[-69.06,43.98],[-70.11617,43.68405],[-70.64548,43.09024],[-70.81489,42.8653],[-70.825,42.335],[-70.495,41.805],[-70.08,41.78],[-70.185,42.145],[-69.88497,41.92283],[-69.96503,41.63717],[-70.64,41.475],[-71.12039,41.49445],[-71.86,41.32],[-72.295,41.27],[-72.87643,41.22065],[-73.71,40.9311],[-72.24126,41.11948],[-71.945,40.93],[-73.345,40.63],[-73.982,40.628],[-73.95232,40.75075],[-74.25671,40.47351],[-73.96244,40.42763],[-74.17838,39.70926],[-74.90604,38.93954],[-74.98041,39.1964],[-75.20002,39.24845],[-75.52805,39.4985],[-75.32,38.96],[-75.07183,38.78203],[-75.05673,38.40412],[-75.37747,38.01551],[-75.94023,37.21689],[-76.03127,37.2566],[-75.72205,37.93705],[-76.23287,38.31921],[-76.35,39.15],[-76.54272,38.71762],[-76.32933,38.08326],[-76.99,38.23999],[-76.30162,37.91794],[-76.25874,36.9664],[-75.9718,36.89726],[-75.86804,36.55125],[-75.72749,35.55074],[-76.36318,34.80854],[-77.39763,34.51201],[-78.05496,33.92547],[-78.55435,33.86133],[-79.06067,33.49395],[-79.20357,33.15839],[-80.30132,32.50935],[-80.86498,32.0333],[-81.33629,31.44049],[-81.49042,30.72999],[-81.31371,30.03552],[-80.98,29.18],[-80.53558,28.47213],[-80.53,28.04],[-80.05654,26.88],[-80.08801,26.20576],[-80.13156,25.81677],[-80.38103,25.20616],[-80.68,25.08],[-81.17213,25.20126],[-81.33,25.64],[-81.71,25.87],[-82.24,26.73],[-82.70515,27.49504],[-82.85526,27.88624],[-82.65,28.55],[-82.93,29.1],[-83.70959,29.93656],[-84.1,30.09],[-85.10882,29.63615],[-85.28784,29.68612],[-85.7731,30.15261],[-86.4,30.4],[-87.53036,30.27433],[-88.41782,30.3849],[-89.18049,30.31598],[-89.59383,30.15999],[-89.41373,29.89419],[-89.43,29.48864],[-89.21767,29.29108],[-89.40823,29.15961],[-89.77928,29.30714],[-90.15463,29.11743],[-90.88022,29.14854],[-91.62678,29.677],[-92.49906,29.5523],[-93.22637,29.78375],[-93.84842,29.71363],[-94.69,29.48],[-95.60026,28.73863],[-96.59404,28.30748],[-97.14,27.83],[-97.37,27.38],[-97.38,26.69],[-97.33,26.21],[-97.14,25.87],[-97.53,25.84],[-98.24,26.06],[-99.02,26.37],[-99.3,26.84],[-99.52,27.54],[-100.11,28.11],[-100.45584,28.69612],[-100.9576,29.38071],[-101.6624,29.7793],[-102.48,29.76],[-103.11,28.97],[-103.94,29.27],[-104.45697,29.57196],[-104.70575,30.12173],[-105.03737,30.64402],[-105.63159,31.08383],[-106.1429,31.39995],[-106.50759,31.75452],[-108.24,31.75485],[-108.24194,31.34222],[-109.035,31.34194],[-111.02361,31.33472],[-113.30498,32.03914],[-114.815,32.52528],[-114.72139,32.72083],[-115.99135,32.61239],[-117.12776,32.53534],[-117.29594,33.04622],[-117.944,33.62124],[-118.4106,33.74091],[-118.51989,34.02778],[-119.081,34.078],[-119.43884,34.34848],[-120.36778,34.44711],[-120.62286,34.60855],[-120.74433,35.15686],[-121.71457,36.16153],[-122.54747,37.55176],[-122.51201,37.78339],[-122.95319,38.11371],[-123.7272,38.95166],[-123.86517,39.76699],[-124.39807,40.3132],[-124.17886,41.14202],[-124.2137,41.99964],[-124.53284,42.76599],[-124.14214,43.70838],[-124.02053,44.6159],[-123.89893,45.52341],[-124.07963,46.86475],[-124.39567,47.72017],[-124.68721,48.18443],[-124.5661,48.37971],[-123.12,48.04],[-122.58736,47.096],[-122.34,47.36],[-122.5,48.18],[-122.84,49],[-120,49],[-117.03121,49],[-116.04818,49],[-113,49],[-110.05,49],[-107.05,49],[-104.04826,48.99986],[-100.65,49],[-97.22872,49.0007],[-95.15907,49],[-95.15609,49.38425],[-94.81758,49.38905]]],[[[-153.00631,57.11584],[-154.00509,56.73468],[-154.5164,56.99275],[-154.67099,57.4612],[-153.76278,57.81657],[-153.22873,57.96897],[-152.56479,57.90143],[-152.14115,57.59106],[-153.00631,57.11584]]],[[[-165.57916,59.90999],[-166.19277,59.75444],[-166.84834,59.94141],[-167.45528,60.21307],[-166.46779,60.38417],[-165.67443,60.29361],[-165.57916,59.90999]]],[[[-171.73166,63.78252],[-171.11443,63.59219],[-170.49111,63.69498],[-169.68251,63.43112],[-168.68944,63.29751],[-168.77194,63.1886],[-169.52944,62.97693],[-170.29056,63.19444],[-170.67139,63.37582],[-171.55306,63.31779],[-171.79111,63.40585],[-171.73166,63.78252]]],[[[-155.06779,71.14778],[-154.34417,70.69641],[-153.90001,70.88999],[-152.21001,70.82999],[-152.27,70.60001],[-150.73999,70.43002],[-149.72,70.53001],[-147.61336,70.21403],[-145.68999,70.12001],[-144.92001,69.98999],[-143.58945,70.15251],[-142.07251,69.85194],[-140.98599,69.712],[-140.9925,66.00003],[-140.99777,60.3064],[-140.013,60.27684],[-139.039,60.00001],[-138.34089,59.56211],[-137.4525,58.905],[-136.47972,59.46389],[-135.47583,59.78778],[-134.945,59.27056],[-134.27111,58.86111],[-133.35555,58.41029],[-132.73042,57.69289],[-131.70781,56.55212],[-130.00778,55.91583],[-129.97999,55.285],[-130.53611,54.80275],[-131.08582,55.17891],[-131.96721,55.49778],[-132.25001,56.37],[-133.53918,57.17889],[-134.07806,58.12307],[-135.03821,58.18771],[-136.62806,58.21221],[-137.80001,58.5],[-139.86779,59.53776],[-140.82527,59.72752],[-142.57444,60.08445],[-143.95888,59.99918],[-145.92556,60.45861],[-147.11437,60.88466],[-148.22431,60.67299],[-148.01807,59.97833],[-148.57082,59.91417],[-149.72786,59.70566],[-150.60824,59.36821],[-151.71639,59.15582],[-151.85943,59.74498],[-151.40972,60.7258],[-150.34694,61.03359],[-150.62111,61.28442],[-151.89584,60.7272],[-152.57833,60.06166],[-154.01917,59.35028],[-153.28751,58.86473],[-154.23249,58.14637],[-155.30749,57.72779],[-156.30833,57.42277],[-156.5561,56.97998],[-158.11722,56.46361],[-158.43332,55.99415],[-159.60333,55.56669],[-160.28972,55.64358],[-161.22305,55.36473],[-162.23777,55.02419],[-163.06945,54.68974],[-164.78557,54.40417],[-164.94223,54.57222],[-163.84834,55.03943],[-162.87,55.34804],[-161.80417,55.89499],[-160.5636,56.00805],[-160.07056,56.41806],[-158.68444,57.01668],[-158.4611,57.21692],[-157.72277,57.57],[-157.55027,58.32833],[-157.04167,58.91888],[-158.19473,58.6158],[-158.51722,58.78778],[-159.05861,58.42419],[-159.71167,58.93139],[-159.98129,58.57255],[-160.35527,59.07112],[-161.355,58.67084],[-161.96889,58.67166],[-162.05499,59.26693],[-161.87417,59.63362],[-162.51806,59.98972],[-163.81834,59.79806],[-164.66222,60.26748],[-165.34639,60.5075],[-165.35083,61.0739],[-166.12138,61.50002],[-165.73445,62.075],[-164.91918,62.63308],[-164.56251,63.14638],[-163.75333,63.21945],[-163.06722,63.05946],[-162.26056,63.54194],[-161.53445,63.45582],[-160.77251,63.76611],[-160.95834,64.2228],[-161.51807,64.40279],[-160.77778,64.7886],[-161.39193,64.77724],[-162.45305,64.55944],[-162.75779,64.33861],[-163.54639,64.55916],[-164.96083,64.44695],[-166.42529,64.68667],[-166.845,65.0889],[-168.11056,65.67],[-166.70527,66.08832],[-164.47471,66.57666],[-163.65251,66.57666],[-163.7886,66.07721],[-161.67777,66.11612],[-162.48971,66.73557],[-163.71972,67.11639],[-164.43099,67.61634],[-165.39029,68.04277],[-166.76444,68.35888],[-166.20471,68.88303],[-164.43081,68.91554],[-163.16861,69.37111],[-162.93057,69.85806],[-161.9089,70.33333],[-160.9348,70.44769],[-159.03918,70.89164],[-158.11972,70.82472],[-156.58082,71.35776],[-155.06779,71.14778]]]]},\"properties\":{\"name\":\"United States\"}}]}","volume":"37","issue":"5","noUsgsAuthors":false,"publicationDate":"2007-06-08","publicationStatus":"PW","scienceBaseUri":"50e4a5cfe4b0e8fec6cdc00a","contributors":{"authors":[{"text":"Larson, S.J.","contributorId":17641,"corporation":false,"usgs":true,"family":"Larson","given":"S.J.","email":"","affiliations":[],"preferred":false,"id":397586,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Gilliom, R. J.","contributorId":60650,"corporation":false,"usgs":true,"family":"Gilliom","given":"R.","email":"","middleInitial":"J.","affiliations":[],"preferred":false,"id":397587,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}}
,{"id":70023416,"text":"70023416 - 2001 - Results from the Big Spring basin water quality monitoring and demonstration projects, Iowa, USA","interactions":[],"lastModifiedDate":"2012-03-12T17:20:10","indexId":"70023416","displayToPublicDate":"2001-01-01T00:00:00","publicationYear":"2001","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1923,"text":"Hydrogeology Journal","active":true,"publicationSubtype":{"id":10}},"title":"Results from the Big Spring basin water quality monitoring and demonstration projects, Iowa, USA","docAbstract":"Agricultural practices, hydrology, and water quality of the 267-km2 Big Spring groundwater drainage basin in Clayton County, Iowa, have been monitored since 1981. Land use is agricultural; nitrate-nitrogen (-N) and herbicides are the resulting contaminants in groundwater and surface water. Ordovician Galena Group carbonate rocks comprise the main aquifer in the basin. Recharge to this karstic aquifer is by infiltration, augmented by sinkhole-captured runoff. Groundwater is discharged at Big Spring, where quantity and quality of the discharge are monitored. Monitoring has shown a threefold increase in groundwater nitrate-N concentrations from the 1960s to the early 1980s. The nitrate-N discharged from the basin typically is equivalent to over one-third of the nitrogen fertilizer applied, with larger losses during wetter years. Atrazine is present in groundwater all year; however, contaminant concentrations in the groundwater respond directly to recharge events, and unique chemical signatures of infiltration versus runoff recharge are detectable in the discharge from Big Spring. Education and demonstration efforts have reduced nitrogen fertilizer application rates by one-third since 1981. Relating declines in nitrate and pesticide concentrations to inputs of nitrogen fertilizer and pesticides at Big Spring is problematic. Annual recharge has varied five-fold during monitoring, overshadowing any water-quality improvements resulting from incrementally decreased inputs. ?? Springer-Verlag 2001.","largerWorkType":{"id":2,"text":"Article"},"largerWorkTitle":"Hydrogeology Journal","largerWorkSubtype":{"id":10,"text":"Journal Article"},"language":"English","doi":"10.1007/s100400100150","issn":"14312174","usgsCitation":"Rowden, R., Liu, H., and Libra, R., 2001, Results from the Big Spring basin water quality monitoring and demonstration projects, Iowa, USA: Hydrogeology Journal, v. 9, no. 5, p. 487-497, https://doi.org/10.1007/s100400100150.","startPage":"487","endPage":"497","numberOfPages":"11","costCenters":[],"links":[{"id":207492,"rank":9999,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.1007/s100400100150"},{"id":232485,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"9","issue":"5","noUsgsAuthors":false,"publicationDate":"2001-07-26","publicationStatus":"PW","scienceBaseUri":"505aaafee4b0c8380cd8662a","contributors":{"authors":[{"text":"Rowden, R.D.","contributorId":63198,"corporation":false,"usgs":true,"family":"Rowden","given":"R.D.","email":"","affiliations":[],"preferred":false,"id":397595,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Liu, H.","contributorId":12222,"corporation":false,"usgs":true,"family":"Liu","given":"H.","affiliations":[],"preferred":false,"id":397593,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Libra, R.D.","contributorId":54353,"corporation":false,"usgs":true,"family":"Libra","given":"R.D.","email":"","affiliations":[],"preferred":false,"id":397594,"contributorType":{"id":1,"text":"Authors"},"rank":3}]}}
,{"id":70023494,"text":"70023494 - 2001 - Identification of alkyl dimethylbenzylammonium surfactants in water samples by solid-phase extraction followed by ion trap LC/MS and LC/MS/MS","interactions":[],"lastModifiedDate":"2021-05-27T18:49:24.646915","indexId":"70023494","displayToPublicDate":"2001-01-01T00:00:00","publicationYear":"2001","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":"Identification of alkyl dimethylbenzylammonium surfactants in water samples by solid-phase extraction followed by ion trap LC/MS and LC/MS/MS","docAbstract":"A novel methodology was developed for the determination of alkyl (C12, C14, and C16) dimethylbenzylammonium chloride (benzalkonium chloride or BAC, Chemical Abstract Service number: 8001-54-5) in water samples. This method is based on solid-phase extraction (SPE) using polymeric cartridges, followed by high-performance liquid chromatography/ion trap mass spectrometry (LC/MS) and tandem mass spectrometry(MS/MS) detection, equipped with an electrospray interface in positive ion mode. Chromatographic separation was achieved for three BAC homologues by using a C18 column and a gradient of acetonitrile/10 millimolar aqueous ammonium formate. Total method recoveries were higher than 71% in different water matrices. The main ions observed by LC/MS were at mass-to-charge ratios (m/z) of 304, 332, and 360, which correspond to the molecular ions of the C12, C14, and C16 alkyl BAC, respectively. The unequivocal structural identification of these compounds in water samples was performed by LC/MS/MS after isolation and subsequent fragmentation of each molecular ion. The main fragmentation observed for the three different homologues corresponded to the loss of the toluyl group in the chemical structure, which leads to the fragment ions at m/z 212, 240, and 268 and a tropylium ion, characteristic of all homologues, at m/z 91. Detection limits for the methodology developed in this work were in the low nanogram-per-liter range. Concentration levels of BAC - ranging from 1.2 to 36.6 micrograms per liter - were found in surface-water samples collected downstream from different wastewater-treatment discharges, thus indicating its input and persistence through the wastewater-treatment process.","language":"English","publisher":"ACS","doi":"10.1021/es001742v","issn":"0013936X","usgsCitation":"Ferrer, I., and Furlong, E., 2001, Identification of alkyl dimethylbenzylammonium surfactants in water samples by solid-phase extraction followed by ion trap LC/MS and LC/MS/MS: Environmental Science & Technology, v. 35, no. 12, p. 2583-2588, https://doi.org/10.1021/es001742v.","productDescription":"6 p.","startPage":"2583","endPage":"2588","costCenters":[{"id":452,"text":"National Water Quality Laboratory","active":true,"usgs":true},{"id":589,"text":"Toxic Substances Hydrology Program","active":true,"usgs":true}],"links":[{"id":232447,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"},{"id":207468,"rank":9999,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.1021/es001742v"}],"volume":"35","issue":"12","noUsgsAuthors":false,"publicationDate":"2001-05-19","publicationStatus":"PW","scienceBaseUri":"505a3820e4b0c8380cd61454","contributors":{"authors":[{"text":"Ferrer, I.","contributorId":97260,"corporation":false,"usgs":true,"family":"Ferrer","given":"I.","email":"","affiliations":[],"preferred":false,"id":397828,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Furlong, E. T. 0000-0002-7305-4603","orcid":"https://orcid.org/0000-0002-7305-4603","contributorId":98346,"corporation":false,"usgs":true,"family":"Furlong","given":"E. T.","affiliations":[],"preferred":false,"id":397829,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}}
,{"id":70023516,"text":"70023516 - 2001 - Potential artifacts in interpretation of differential breakthrough of colloids and dissolved tracers in the context of transport in a zero-valent iron permeable reactive barrier","interactions":[],"lastModifiedDate":"2018-12-03T09:30:36","indexId":"70023516","displayToPublicDate":"2001-01-01T00:00:00","publicationYear":"2001","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1861,"text":"Ground Water","active":true,"publicationSubtype":{"id":10}},"title":"Potential artifacts in interpretation of differential breakthrough of colloids and dissolved tracers in the context of transport in a zero-valent iron permeable reactive barrier","docAbstract":"Many published studies have used visual comparison of the timing of peak breakthrough of colloids versus conservative dissolved tracers (hereafter referred to as dissolved tracers or tracers) in subsurface media to determine whether they are advected differently, and to elucidate the mechanisms of differential advection. This purely visual approach of determining differential advection may have artifacts, however, due to the attachment of colloids to subsurface media. The attachment of colloids to subsurface media may shift the colloidal peak breakthrough to earlier times, causing an apparent \"faster\" peak breakthrough of colloids relative to dissolve tracers even though the transport velocities for the colloids and the dissolved tracers may actually be equivalent. In this paper, a peak shift analysis was presented to illustrate the artifacts associated with the purely visual approach in determining differential advection, and to quantify the peak shift due to colloid attachment. This peak shift analysis was described within the context of microsphere and bromide transport within a zero-valent iron (ZVI) permeable reactive barrier (PRB) located in Fry Canyon, Utah. Application of the peak shift analysis to the field microsphere and bromide breakthrough data indicated that differential advection of the microspheres relative to the bromide occurred in the monitoring wells closest to the injection well in the PRB. It was hypothesized that the physical heterogeneity at the grain scale, presumably arising from differences in inter- versus intra-particle porosity, contributed to the differential advection of the microspheres versus the bromide in the PRB. The relative breakthrough (RB) of microspheres at different wells was inversely related to the ionic strength of ground water at these wells, in agreement with numerous studies showing that colloid attachment is directly related to solution ionic strength.","language":"English","publisher":"Wiley","doi":"10.1111/j.1745-6584.2001.tb02471.x","issn":"0017467X","usgsCitation":"Zhang, P., Johnson, W., Piana, M., Fuller, C.C., and Naftz, D.L., 2001, Potential artifacts in interpretation of differential breakthrough of colloids and dissolved tracers in the context of transport in a zero-valent iron permeable reactive barrier: Ground Water, v. 39, no. 6, p. 831-840, https://doi.org/10.1111/j.1745-6584.2001.tb02471.x.","productDescription":"10 p.","startPage":"831","endPage":"840","costCenters":[{"id":589,"text":"Toxic Substances Hydrology Program","active":true,"usgs":true}],"links":[{"id":232136,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"39","issue":"6","noUsgsAuthors":false,"publicationDate":"2005-12-13","publicationStatus":"PW","scienceBaseUri":"505a7ebde4b0c8380cd7a703","contributors":{"authors":[{"text":"Zhang, P.","contributorId":92822,"corporation":false,"usgs":true,"family":"Zhang","given":"P.","email":"","affiliations":[],"preferred":false,"id":397901,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Johnson, W.P.","contributorId":43315,"corporation":false,"usgs":true,"family":"Johnson","given":"W.P.","email":"","affiliations":[],"preferred":false,"id":397900,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Piana, M.J.","contributorId":22940,"corporation":false,"usgs":true,"family":"Piana","given":"M.J.","email":"","affiliations":[],"preferred":false,"id":397897,"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":397898,"contributorType":{"id":1,"text":"Authors"},"rank":4},{"text":"Naftz, D. L.","contributorId":40624,"corporation":false,"usgs":true,"family":"Naftz","given":"D.","email":"","middleInitial":"L.","affiliations":[],"preferred":false,"id":397899,"contributorType":{"id":1,"text":"Authors"},"rank":5}]}}
,{"id":70023547,"text":"70023547 - 2001 - Natural attenuation of volatile organic compounds (VOCs) in the leachate plume of a municipal landfill: Using alkylbenzenes as process probes","interactions":[],"lastModifiedDate":"2018-12-03T10:01:47","indexId":"70023547","displayToPublicDate":"2001-01-01T00:00:00","publicationYear":"2001","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":3825,"text":"Groundwater","active":true,"publicationSubtype":{"id":10}},"title":"Natural attenuation of volatile organic compounds (VOCs) in the leachate plume of a municipal landfill: Using alkylbenzenes as process probes","docAbstract":"More than 70 individual VOCs were identified in the leachate plume of a closed municipal landfill. Concentrations were low when compared with data published for other landfills, and total VOCs accounted for less than 0.1% of the total dissolved organic carbon. The VOC concentrations in the core of the anoxic leachate plume are variable, but in all cases they were found to be near or below detection limits within 200 m of the landfall. In contrast to the VOCs, the distributions of chloride ion, a conservative tracer, and nonvolatile dissolved organic carbon, indicate little dilution over the same distance. Thus, natural attentuation processes are effectively limiting migration of the VOC plume. The distribution of C2-3-benzenes, paired on the basis of their octanol-water partition coefficients and Henry's law constants, were systematically evaluated to assess the relative importance of volatilization, sorption, and biodegradation as attenuation mechanisms. Based on our data, biodegradation appears to be the process primarily responsible for the observed attenuation of VOCs at this site. We believe that the alkylbenzenes are powerful process probes that can and should be exploited in studies of natural attenuation in contaminated ground water systems.","language":"English","publisher":"Wiley","doi":"10.1111/j.1745-6584.2001.tb02300.x","issn":"0017467X","usgsCitation":"Eganhouse, R., Cozzarelli, I.M., Scholl, M.A., and Matthews, L., 2001, Natural attenuation of volatile organic compounds (VOCs) in the leachate plume of a municipal landfill: Using alkylbenzenes as process probes: Groundwater, v. 39, no. 2, p. 192-202, https://doi.org/10.1111/j.1745-6584.2001.tb02300.x.","productDescription":"11 p.","startPage":"192","endPage":"202","numberOfPages":"11","costCenters":[{"id":589,"text":"Toxic Substances Hydrology Program","active":true,"usgs":true}],"links":[{"id":232572,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"39","issue":"2","noUsgsAuthors":false,"publicationDate":"2005-12-13","publicationStatus":"PW","scienceBaseUri":"505a62e1e4b0c8380cd72177","contributors":{"authors":[{"text":"Eganhouse, Robert P. eganhous@usgs.gov","contributorId":2031,"corporation":false,"usgs":true,"family":"Eganhouse","given":"Robert P.","email":"eganhous@usgs.gov","affiliations":[{"id":436,"text":"National Research Program - Eastern Branch","active":true,"usgs":true}],"preferred":true,"id":397994,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Cozzarelli, Isabelle M. 0000-0002-5123-1007 icozzare@usgs.gov","orcid":"https://orcid.org/0000-0002-5123-1007","contributorId":1693,"corporation":false,"usgs":true,"family":"Cozzarelli","given":"Isabelle","email":"icozzare@usgs.gov","middleInitial":"M.","affiliations":[{"id":49175,"text":"Geology, Energy & Minerals Science Center","active":true,"usgs":true},{"id":436,"text":"National Research Program - Eastern Branch","active":true,"usgs":true}],"preferred":true,"id":397993,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Scholl, Martha A. 0000-0001-6994-4614 mascholl@usgs.gov","orcid":"https://orcid.org/0000-0001-6994-4614","contributorId":1920,"corporation":false,"usgs":true,"family":"Scholl","given":"Martha","email":"mascholl@usgs.gov","middleInitial":"A.","affiliations":[{"id":37277,"text":"WMA - Earth System Processes Division","active":true,"usgs":true}],"preferred":true,"id":397996,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Matthews, L.L.","contributorId":81278,"corporation":false,"usgs":true,"family":"Matthews","given":"L.L.","email":"","affiliations":[],"preferred":false,"id":397995,"contributorType":{"id":1,"text":"Authors"},"rank":4}]}}
,{"id":70023560,"text":"70023560 - 2001 - User interface for ground-water modeling: Arcview extension","interactions":[],"lastModifiedDate":"2012-03-12T17:20:01","indexId":"70023560","displayToPublicDate":"2001-01-01T00:00:00","publicationYear":"2001","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":2341,"text":"Journal of Hydrologic Engineering","active":true,"publicationSubtype":{"id":10}},"title":"User interface for ground-water modeling: Arcview extension","docAbstract":"Numerical simulation for ground-water modeling often involves handling large input and output data sets. A geographic information system (GIS) provides an integrated platform to manage, analyze, and display disparate data and can greatly facilitate modeling efforts in data compilation, model calibration, and display of model parameters and results. Furthermore, GIS can be used to generate information for decision making through spatial overlay and processing of model results. Arc View is the most widely used Windows-based GIS software that provides a robust user-friendly interface to facilitate data handling and display. An extension is an add-on program to Arc View that provides additional specialized functions. An Arc View interface for the ground-water flow and transport models MODFLOW and MT3D was built as an extension for facilitating modeling. The extension includes preprocessing of spatially distributed (point, line, and polygon) data for model input and postprocessing of model output. An object database is used for linking user dialogs and model input files. The Arc View interface utilizes the capabilities of the 3D Analyst extension. Models can be automatically calibrated through the Arc View interface by external linking to such programs as PEST. The efficient pre- and postprocessing capabilities and calibration link were demonstrated for ground-water modeling in southwest Kansas.","largerWorkType":{"id":2,"text":"Article"},"largerWorkTitle":"Journal of Hydrologic Engineering","largerWorkSubtype":{"id":10,"text":"Journal Article"},"language":"English","doi":"10.1061/(ASCE)1084-0699(2001)6:3(251)","issn":"10840699","usgsCitation":"Tsou, M., and Whittemore, D.O., 2001, User interface for ground-water modeling: Arcview extension: Journal of Hydrologic Engineering, v. 6, no. 3, p. 251-257, https://doi.org/10.1061/(ASCE)1084-0699(2001)6:3(251).","startPage":"251","endPage":"257","numberOfPages":"7","costCenters":[],"links":[{"id":232176,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"},{"id":207323,"rank":9999,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.1061/(ASCE)1084-0699(2001)6:3(251)"}],"volume":"6","issue":"3","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505bbfc5e4b08c986b329d68","contributors":{"authors":[{"text":"Tsou, Ming-shu","contributorId":20507,"corporation":false,"usgs":false,"family":"Tsou","given":"Ming-shu","email":"","affiliations":[],"preferred":false,"id":398039,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Whittemore, Donald O.","contributorId":28748,"corporation":false,"usgs":false,"family":"Whittemore","given":"Donald","email":"","middleInitial":"O.","affiliations":[],"preferred":false,"id":398040,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}}
,{"id":70023776,"text":"70023776 - 2001 - Pesticides associated with suspended sediments entering San Francisco Bay following the first major storm of water year 1996","interactions":[],"lastModifiedDate":"2018-11-28T11:00:49","indexId":"70023776","displayToPublicDate":"2001-01-01T00:00:00","publicationYear":"2001","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1583,"text":"Estuaries","active":true,"publicationSubtype":{"id":10}},"title":"Pesticides associated with suspended sediments entering San Francisco Bay following the first major storm of water year 1996","docAbstract":"<p><span>Estuaries receive large quantities of suspended sediments following the first major storm of the water year. The first-flush events transport the majority of suspended sediments in any given year, and because of their relative freshness in the hydrologic system, these sediments may carry a significant amount of the sediment-associated pesticide load transported into estuaries. To characterize sediment-associated pesticides during a first-flush event, water and suspended sediment samples were collected at the head of the San Francisco Bay during the peak in suspended sediment concentration that followed the first major storm of the 1996 hydrologic year. Samples were analyzed for a variety of parameters as well as 19 pesticides and degradation products that span a wide range of hydrophobicity. Tidal mixing at the head of the estuary mixed relatively fresh suspended sediment transported down the rivers with suspended sediments in estuary waters. Segregation of the samples into groups with similar degrees of mixing between river and estuary water revealed that transport of suspended sediments from the Sacramento-San Joaquin drainage basin strongly influenced the concentration and distribution of sediment-associated pesticides entering the San Francisco Bay. The less-mixed suspended sediment contained a different distribution of pesticides than the sediments exposed to greater mixing. Temporal trends were evident in pesticide content after samples were segregated according to mixing history. These results indicate sampling strategies that collect at a low frequency or do not compare samples with similar mixing histories will not elucidate basin processes. Despite the considerable influence of mixing, a large number of pesticides were found associated with the suspended sediments. Few pesticides were found in the concurrent water samples and in concentrations much lower than predicted from equilibrium partitioning between the aqueous and sedimentary phases. The observed sediment-associated pesticide concentrations may reflect disequilibria between sedimentary and aqueous phases resulting from long equilibration times at locations where pesticides were applied, and relatively short transit times over which re-equilibration may occur.</span></p>","language":"English","publisher":"Springer","doi":"10.2307/1353239","issn":"01608347","usgsCitation":"Bergamaschi, B.A., Kuivila, K., and Fram, M.S., 2001, Pesticides associated with suspended sediments entering San Francisco Bay following the first major storm of water year 1996: Estuaries, v. 24, no. 3, p. 368-380, https://doi.org/10.2307/1353239.","productDescription":"13 p.","startPage":"368","endPage":"380","onlineOnly":"N","additionalOnlineFiles":"N","costCenters":[{"id":154,"text":"California Water Science Center","active":true,"usgs":true},{"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":232466,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"24","issue":"3","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505a7736e4b0c8380cd7844c","contributors":{"authors":[{"text":"Bergamaschi, Brian A. 0000-0002-9610-5581 bbergama@usgs.gov","orcid":"https://orcid.org/0000-0002-9610-5581","contributorId":140776,"corporation":false,"usgs":true,"family":"Bergamaschi","given":"Brian","email":"bbergama@usgs.gov","middleInitial":"A.","affiliations":[{"id":154,"text":"California Water Science Center","active":true,"usgs":true}],"preferred":true,"id":398799,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Kuivila, Kathryn 0000-0001-7940-489X kkuivila@usgs.gov","orcid":"https://orcid.org/0000-0001-7940-489X","contributorId":190790,"corporation":false,"usgs":true,"family":"Kuivila","given":"Kathryn","email":"kkuivila@usgs.gov","affiliations":[{"id":154,"text":"California Water Science Center","active":true,"usgs":true},{"id":518,"text":"Oregon Water Science Center","active":true,"usgs":true}],"preferred":true,"id":398800,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Fram, Miranda S. 0000-0002-6337-059X mfram@usgs.gov","orcid":"https://orcid.org/0000-0002-6337-059X","contributorId":1156,"corporation":false,"usgs":true,"family":"Fram","given":"Miranda","email":"mfram@usgs.gov","middleInitial":"S.","affiliations":[{"id":154,"text":"California Water Science Center","active":true,"usgs":true}],"preferred":true,"id":398801,"contributorType":{"id":1,"text":"Authors"},"rank":3}]}}
]}