{"pageNumber":"1198","pageRowStart":"29925","pageSize":"25","recordCount":46734,"records":[{"id":70021757,"text":"70021757 - 1999 - Magmatic interactions as recorded in plagioclase phenocrysts of Chaos Crags, Lassen Volcanic Center, California","interactions":[],"lastModifiedDate":"2024-05-31T11:57:56.140057","indexId":"70021757","displayToPublicDate":"1999-01-01T00:00:00","publicationYear":"1999","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":2420,"text":"Journal of Petrology","active":true,"publicationSubtype":{"id":10}},"title":"Magmatic interactions as recorded in plagioclase phenocrysts of Chaos Crags, Lassen Volcanic Center, California","docAbstract":"The silicic lava domes of Chaos Crags in Lassen Volcanic National Park contain a suite of variably quenched, hybrid basaltic andesite magmatic inclusions. The inclusions represent thorough mixing between rhyodacite and basalt recharge liquids accompanied by some mechanical disaggregation of the inclusions resulting in crystals mixing into the rhyodacite host preserved by quenching on dome emplacement. 87Sr/86Sr ratios (~0.7037-0.7038) of the inclusions are distinctly lower than those of the host rhyodacite (~0.704-0.7041), which are used to fingerprint the origin of mineral components and to monitor the mixing and mingling process. Chemical, isotopic, and textural characteristics indicate that the inclusions are hybrid magmas formed from the mixing and undercooling of recharge basaltic magma with rhyodacitic magma. All the host magma phenocrysts (biotite, plagioclase, hornblende and quartz crystals) also occur in the inclusions, where they are rimmed by reaction products. Compositional and strontium isotopic data from cores of unresorbed plagioclase crystals in the host rhyodacite, partially resorbed plagioclase crystals enclosed within basaltic andesite inclusions, and partially resorbed plagioclase crystals in the rhyodacitic host are all similar. Rim 87Sr/86Sr ratios of the partially resorbed plagioclase crystals in both inclusions and host are lower and close to those of the whole-rock hybrid basaltic andesite values. This observation indicates that some crystals originally crystallized in the silicic host, were partially resorbed and subsequently overgrown in the hybrid basaltic andesite magma, and then some of these partially resorbed plagioclase crystals were recycled back into the host rhyodacite. Textural evidence, in the form of sieve zones and major dissolution boundaries of the resorbed plagioclase crystals, indicates immersion of crystals into a hotter, more calcic magma. The occurrence of partially resorbed plagioclase together with plagioclase microlites and olivine crystals reflects disaggregation of inclusions and mingling of this material into the silicic host. These processes are commonplace in some orogenic magma systems and may be elucidated by isotopic microsampling and analysis of the plagioclases crystallizing from them.","language":"English","publisher":"Oxford Academic","doi":"10.1093/petroj/40.5.787","issn":"00223530","usgsCitation":"Tepley, F.J., Davidson, J., and Clynne, M., 1999, Magmatic interactions as recorded in plagioclase phenocrysts of Chaos Crags, Lassen Volcanic Center, California: Journal of Petrology, v. 40, no. 5, p. 787-806, https://doi.org/10.1093/petroj/40.5.787.","productDescription":"20 p.","startPage":"787","endPage":"806","numberOfPages":"20","costCenters":[],"links":[{"id":487416,"rank":2,"type":{"id":40,"text":"Open Access Publisher Index Page"},"url":"https://doi.org/10.1093/petroj/40.5.787","text":"Publisher Index Page"},{"id":229366,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"40","issue":"5","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505a4b49e4b0c8380cd69426","contributors":{"authors":[{"text":"Tepley, F. J. III","contributorId":99723,"corporation":false,"usgs":true,"family":"Tepley","given":"F.","suffix":"III","email":"","middleInitial":"J.","affiliations":[],"preferred":false,"id":391040,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Davidson, J.P.","contributorId":16123,"corporation":false,"usgs":true,"family":"Davidson","given":"J.P.","email":"","affiliations":[],"preferred":false,"id":391038,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Clynne, M.A.","contributorId":90722,"corporation":false,"usgs":true,"family":"Clynne","given":"M.A.","affiliations":[],"preferred":false,"id":391039,"contributorType":{"id":1,"text":"Authors"},"rank":3}]}}
,{"id":70021908,"text":"70021908 - 1999 - Reconstructing late Quaternary deep-water masses in the eastern Arctic Ocean using benthonic Ostracoda","interactions":[],"lastModifiedDate":"2012-03-12T17:19:38","indexId":"70021908","displayToPublicDate":"1999-01-01T00:00:00","publicationYear":"1999","noYear":false,"publicationType":{"id":24,"text":"Conference Paper"},"publicationSubtype":{"id":19,"text":"Conference Paper"},"title":"Reconstructing late Quaternary deep-water masses in the eastern Arctic Ocean using benthonic Ostracoda","docAbstract":"The distribution of Ostracoda in three long cores from the deep eastern Arctic Ocean was studied to determine the palaeoceanographical history of the Eurasian Basin during the late Quaternary. The samples for this study were obtained from the Lomonosov Ridge, Morris Jesup Rise and Yermak Plateau during the Arctic 91 expedition. Ostracoda previously studied in coretops at the same sites as the present study have shown that individual species have a strong association with different water masses and bathymetry. Throughout the late Quaternary, cores exhibit ostracod-rich layers separated by barren intervals. On the basis of biostratigraphical, isotopic and palaeomagnetic data the fossiliferous levels are interpreted as representing interglacial stages. The twenty most significant species were selected for subsequent quantitative investigation using Cluster and Factor analyses, in order to determine similarity and variance between the assemblages. An additional statistical method employing Modern Analogues and the Squared Chord Distance dissimilarity coefficient was utilized to compare the present late Quaternary fossil samples with a modern Arctic database. The results reveal a major faunal division within the Arctic Ocean Deep Water (AODW). Highly abundant and diverse assemblages within the cores were found to group and have good analogues with the Recent bathyal depth (1000-2500 m) upper AODW assemblages. Conversely, assemblages with low abundance and diversity correlate well with abyssal depth (> 3000 m) lower AODW assemblages. The palaeoceanographical history is complicated by the influence of adjacent water masses such as Canada Basin Deep Water (CBDW), Greenland Sea Deep Water (GSDW) and most importantly, Arctic Intermediate Water (AIW), which all had an influence on the ostracod assemblages during the late Quaternary. An enhanced flow of warm saline AIW into the Eurasian Basin results in species-rich upper AODW assemblages having good analogues down to 2750 m in the water column. In contrast, lower AODW assemblages influenced by cold well-oxygenated GSDW give analogues at depths as shallow as 1000 m. The faunal changes are the consequence of rapid climatic fluctuations in the eastern Arctic Ocean during the late Quaternary that are intrinsically linked to palaeoceanographical alternations in warm and cold current inflow from adjacent basins.","largerWorkTitle":"Marine Micropaleontology","language":"English","doi":"10.1016/S0377-8398(99)00022-5","issn":"03778398","usgsCitation":"Jones, R.L., Whatley, R., Cronin, T.M., and Dowsett, H., 1999, Reconstructing late Quaternary deep-water masses in the eastern Arctic Ocean using benthonic Ostracoda, <i>in</i> Marine Micropaleontology, v. 37, no. 3-4, p. 251-272, https://doi.org/10.1016/S0377-8398(99)00022-5.","startPage":"251","endPage":"272","numberOfPages":"22","costCenters":[],"links":[{"id":206288,"rank":9999,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.1016/S0377-8398(99)00022-5"},{"id":229311,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"37","issue":"3-4","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"50e4a250e4b0e8fec6cdb573","contributors":{"authors":[{"text":"Jones, R. Ll","contributorId":50678,"corporation":false,"usgs":true,"family":"Jones","given":"R.","email":"","middleInitial":"Ll","affiliations":[],"preferred":false,"id":391638,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Whatley, R.C.","contributorId":85211,"corporation":false,"usgs":true,"family":"Whatley","given":"R.C.","affiliations":[],"preferred":false,"id":391639,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Cronin, T. M. 0000-0002-2643-0979","orcid":"https://orcid.org/0000-0002-2643-0979","contributorId":42613,"corporation":false,"usgs":true,"family":"Cronin","given":"T.","email":"","middleInitial":"M.","affiliations":[{"id":40020,"text":"Florence Bascom Geoscience Center","active":true,"usgs":true}],"preferred":false,"id":391637,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Dowsett, H.J. 0000-0003-1983-7524","orcid":"https://orcid.org/0000-0003-1983-7524","contributorId":87924,"corporation":false,"usgs":true,"family":"Dowsett","given":"H.J.","affiliations":[],"preferred":false,"id":391640,"contributorType":{"id":1,"text":"Authors"},"rank":4}]}}
,{"id":70022008,"text":"70022008 - 1999 - Techniques for accurate estimation of net discharge in a tidal channel","interactions":[],"lastModifiedDate":"2012-03-12T17:19:39","indexId":"70022008","displayToPublicDate":"1999-01-01T00:00:00","publicationYear":"1999","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":3157,"text":"Proceedings of the IEEE Working Conference on Current Measurement","active":true,"publicationSubtype":{"id":10}},"title":"Techniques for accurate estimation of net discharge in a tidal channel","docAbstract":"An ultrasonic velocity meter discharge-measurement site in a tidally affected region of the Sacramento-San Joaquin rivers was used to study the accuracy of the index velocity calibration procedure. Calibration data consisting of ultrasonic velocity meter index velocity and concurrent acoustic Doppler discharge measurement data were collected during three time periods. The relative magnitude of equipment errors, acoustic Doppler discharge measurement errors, and calibration errors were evaluated. Calibration error was the most significant source of error in estimating net discharge. Using a comprehensive calibration method, net discharge estimates developed from the three sets of calibration data differed by less than an average of 4 cubic meters per second. Typical maximum flow rates during the data-collection period averaged 750 cubic meters per second.","largerWorkType":{"id":2,"text":"Article"},"largerWorkTitle":"Proceedings of the IEEE Working Conference on Current Measurement","largerWorkSubtype":{"id":10,"text":"Journal Article"},"conferenceTitle":"Proceedings of the 1999 IEEE 6th Working Conference on Current Measurement","conferenceDate":"11 March 1999 through 13 March 1999","conferenceLocation":"San Diego, CA, USA","language":"English","publisher":"IEEE","publisherLocation":"Piscataway, NJ, United States","usgsCitation":"Simpson, M.R., and Bland, R., 1999, Techniques for accurate estimation of net discharge in a tidal channel: Proceedings of the IEEE Working Conference on Current Measurement, p. 125-130.","startPage":"125","endPage":"130","numberOfPages":"6","costCenters":[],"links":[{"id":229194,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505ba417e4b08c986b3200d2","contributors":{"authors":[{"text":"Simpson, Michael R.","contributorId":90704,"corporation":false,"usgs":true,"family":"Simpson","given":"Michael","email":"","middleInitial":"R.","affiliations":[],"preferred":false,"id":392024,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Bland, Roger","contributorId":99721,"corporation":false,"usgs":true,"family":"Bland","given":"Roger","email":"","affiliations":[],"preferred":false,"id":392025,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}}
,{"id":70021775,"text":"70021775 - 1999 - The sensitivity of terrestrial carbon storage to historical climate variability and atmospheric CO2 in the United States","interactions":[],"lastModifiedDate":"2025-09-23T15:34:34.052545","indexId":"70021775","displayToPublicDate":"1999-01-01T00:00:00","publicationYear":"1999","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":3528,"text":"Tellus, Series B: Chemical and Physical Meteorology","active":true,"publicationSubtype":{"id":10}},"title":"The sensitivity of terrestrial carbon storage to historical climate variability and atmospheric CO2 in the United States","docAbstract":"We use the Terrestrial Ecosystem Model (TEM, Version 4.1) and the land cover data set of the international geosphere-biosphere program to investigate how increasing atmospheric CO2 concentration and climate variability during 1900-1994 affect the carbon storage of terrestrial ecosystems in the conterminous USA, and how carbon storage has been affected by land-use change. The estimates of TEM indicate that over the past 95 years a combination of increasing atmospheric CO2 with historical temperature and precipitation variability causes a 4.2% (4.3 Pg C) decrease in total carbon storage of potential vegetation in the conterminous US, with vegetation carbon decreasing by 7.2% (3.2 Pg C) and soil organic carbon decreasing by 1.9% (1.1 Pg C). Several dry periods including the 1930s and 1950s are responsible for the loss of carbon storage. Our factorial experiments indicate that precipitation variability alone decreases total carbon storage by 9.5%. Temperature variability alone does not significantly affect carbon storage. The effect of CO2 fertilization alone increases total carbon storage by 4.4%. The effects of increasing atmospheric CO2 and climate variability are not additive. Interactions among CO2, temperature and precipitation increase total carbon storage by 1.1%. Our study also shows substantial year-to-year variations in net carbon exchange between the atmosphere and terrestrial ecosystems due to climate variability. Since the 1960s, we estimate these terrestrial ecosystems have acted primarily as a sink of atmospheric CO2 as a result of wetter weather and higher atmospheric CO2 concentrations. For the 1980s, we estimate the natural terrestrial ecosystems, excluding cropland and urban areas, of the conterminous US have accumulated 78.2 Tg C yr-1 because of the combined effect of increasing atmospheric CO2 and climate variability. For the conterminous US, we estimate that the conversion of natural ecosystems to cropland and urban areas has caused a 18.2% (17.7 Pg C) reduction in total carbon storage from that estimated for potential vegetation. The carbon sink capacity of natural terrestrial ecosystems in the conterminous US is about 69% of that estimated for potential vegetation.","language":"English","publisher":"Tellus Journals","doi":"10.3402/tellusb.v51i2.16318","issn":"02806509","usgsCitation":"Tian, H., Melillo, J.M., Kicklighter, D., McGuire, A., and Helfrich, J., 1999, The sensitivity of terrestrial carbon storage to historical climate variability and atmospheric CO2 in the United States: Tellus, Series B: Chemical and Physical Meteorology, v. 51, no. 2, p. 414-452, https://doi.org/10.3402/tellusb.v51i2.16318.","productDescription":"39 p.","startPage":"414","endPage":"452","numberOfPages":"39","costCenters":[],"links":[{"id":496148,"rank":2,"type":{"id":40,"text":"Open Access Publisher Index Page"},"url":"https://doi.org/10.3402/tellusb.v51i2.16318","text":"Publisher Index Page"},{"id":229629,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"51","issue":"2","noUsgsAuthors":false,"publicationDate":"1999-01-01","publicationStatus":"PW","scienceBaseUri":"505bb00ce4b08c986b324bc6","contributors":{"authors":[{"text":"Tian, H.","contributorId":43524,"corporation":false,"usgs":true,"family":"Tian","given":"H.","affiliations":[],"preferred":false,"id":391107,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Melillo, J. M.","contributorId":73139,"corporation":false,"usgs":false,"family":"Melillo","given":"J.","email":"","middleInitial":"M.","affiliations":[],"preferred":false,"id":391108,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Kicklighter, D. W.","contributorId":31537,"corporation":false,"usgs":false,"family":"Kicklighter","given":"D. W.","affiliations":[{"id":13627,"text":"Woods Hole Oceanographic Institution, Woods Hole, MA","active":true,"usgs":false}],"preferred":false,"id":391106,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"McGuire, A. D.","contributorId":16552,"corporation":false,"usgs":true,"family":"McGuire","given":"A. D.","affiliations":[],"preferred":false,"id":391105,"contributorType":{"id":1,"text":"Authors"},"rank":4},{"text":"Helfrich, J.","contributorId":11346,"corporation":false,"usgs":false,"family":"Helfrich","given":"J.","affiliations":[],"preferred":false,"id":391104,"contributorType":{"id":1,"text":"Authors"},"rank":5}]}}
,{"id":70021969,"text":"70021969 - 1999 - Application of geologic map information to water quality issues in the southern part of the Chesapeake Bay watershed, Maryland and Virginia, eastern United States","interactions":[],"lastModifiedDate":"2012-03-12T17:19:55","indexId":"70021969","displayToPublicDate":"1999-01-01T00:00:00","publicationYear":"1999","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":2302,"text":"Journal of Geochemical Exploration","active":true,"publicationSubtype":{"id":10}},"title":"Application of geologic map information to water quality issues in the southern part of the Chesapeake Bay watershed, Maryland and Virginia, eastern United States","docAbstract":"Geologic map units contain much information about the mineralogy, chemistry, and physical attributes of the rocks mapped. This paper presents information from regional-scale geologic maps in Maryland and Virginia, which are in the southern part of the Chesapeake Bay watershed in the eastern United States. The geologic map information is discussed and analyzed in relation to water chemistry data from shallow wells and stream reaches in the area. Two environmental problems in the Chesapeake Bay watershed are used as test examples. The problems, high acidity and high nitrate concentrations in streams and rivers, tend to be mitigated by some rock and sediment types and not by others. Carbonate rocks (limestone, dolomite, and carbonate-cemented rocks) have the greatest capacity to neutralize acidic ground water and surface water in contact with them. Rocks and sediments having high carbon or sulfur contents (such as peat and black shale) potentially contribute the most toward denitrification of ground water and surface water in contact with them. Rocks and sediments that are composed mostly of quartz, feldspar, and light-colored clay (rocks such as granite and sandstone, sediments such as sand and gravel) tend not to alter the chemistry of waters that are in contact with them. The testing of relationships between regionally mapped geologic units and water chemistry is in a preliminary stage, and initial results are encouraging.Geologic map units contain much information about the mineralogy, chemistry, and physical attributes of the rocks mapped. This paper presents information from regional-scale geologic maps in Maryland and Virginia, which are in the southern part of the Chesapeake Bay watershed in the eastern United States. The geologic map information is discussed and analyzed in relation to water chemistry data from shallow wells and stream reaches in the area. Two environmental problems in the Chesapeake Bay watershed are used as test examples. The problems, high acidity and high nitrate concentrations in streams and rivers, tend to be mitigated by some rock and sediment types and not by others. Carbonate rocks (limestone, dolomite, and carbonate-cemented rocks) have the greatest capacity to neutralize acidic ground water and surface water in contact with them. Rocks and sediments having high carbon or sulfur contents (such as peat and black shale) potentially contribute the most toward denitrification of ground water and surface water in contact with them. Rocks and sediments that are composed mostly of quartz, feldspar, and light-colored clay (rocks such as granite and sandstone, sediments such as sand and gravel) tend not to alter the chemistry of waters that are in contact with them. The testing of relationships between regionally mapped geologic units and water chemistry is in a preliminary stage, and initial results are encouraging.","largerWorkType":{"id":2,"text":"Article"},"largerWorkTitle":"Journal of Geochemical Exploration","largerWorkSubtype":{"id":10,"text":"Journal Article"},"conferenceTitle":"Proceedings of the 4th International Symposium on Environmental Geochemistry ISEG. Pt 1 (of 2)","conferenceDate":"5 October 1997 through 10 October 1997","conferenceLocation":"Vail, CO, USA","language":"English","publisher":"Elsevier Sci B.V.","publisherLocation":"Amsterdam, Netherlands","doi":"10.1016/S0375-6742(98)00043-0","issn":"03756742","usgsCitation":"McCartan, L., Peper, J., Bachman, L., and Horton, J.W., 1999, Application of geologic map information to water quality issues in the southern part of the Chesapeake Bay watershed, Maryland and Virginia, eastern United States: Journal of Geochemical Exploration, v. 64, no. 1-3 -3 pt 1, p. 355-376, https://doi.org/10.1016/S0375-6742(98)00043-0.","startPage":"355","endPage":"376","numberOfPages":"22","costCenters":[],"links":[{"id":206207,"rank":9999,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.1016/S0375-6742(98)00043-0"},{"id":229122,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"64","issue":"1-3 -3 pt 1","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"5059ec9fe4b0c8380cd493b2","contributors":{"authors":[{"text":"McCartan, L.","contributorId":55153,"corporation":false,"usgs":true,"family":"McCartan","given":"L.","affiliations":[],"preferred":false,"id":391897,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Peper, J. D.","contributorId":29387,"corporation":false,"usgs":true,"family":"Peper","given":"J. D.","affiliations":[],"preferred":false,"id":391895,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Bachman, L. J.","contributorId":47760,"corporation":false,"usgs":true,"family":"Bachman","given":"L. J.","affiliations":[],"preferred":false,"id":391896,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Horton, J. Wright Jr. 0000-0001-6756-6365 whorton@usgs.gov","orcid":"https://orcid.org/0000-0001-6756-6365","contributorId":81184,"corporation":false,"usgs":true,"family":"Horton","given":"J.","suffix":"Jr.","email":"whorton@usgs.gov","middleInitial":"Wright","affiliations":[],"preferred":false,"id":391898,"contributorType":{"id":1,"text":"Authors"},"rank":4}]}}
,{"id":70021992,"text":"70021992 - 1999 - Geostatistical applications in ground-water modeling in south-central Kansas","interactions":[],"lastModifiedDate":"2012-03-12T17:19:38","indexId":"70021992","displayToPublicDate":"1999-01-01T00:00:00","publicationYear":"1999","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":"Geostatistical applications in ground-water modeling in south-central Kansas","docAbstract":"This paper emphasizes the supportive role of geostatistics in applying ground-water models. Field data of 1994 ground-water level, bedrock, and saltwater-freshwater interface elevations in south-central Kansas were collected and analyzed using the geostatistical approach. Ordinary kriging was adopted to estimate initial conditions for ground-water levels and topography of the Permian bedrock at the nodes of a finite difference grid used in a three-dimensional numerical model. Cokriging was used to estimate initial conditions for the saltwater-freshwater interface. An assessment of uncertainties in the estimated data is presented. The kriged and cokriged estimation variances were analyzed to evaluate the adequacy of data employed in the modeling. Although water levels and bedrock elevations are well described by spherical semivariogram models, additional data are required for better cokriging estimation of the interface data. The geostatistically analyzed data were employed in a numerical model of the Siefkes site in the project area. Results indicate that the computed chloride concentrations and ground-water drawdowns reproduced the observed data satisfactorily.This paper emphasizes the supportive role of geostatistics in applying ground-water models. Field data of 1994 ground-water level, bedrock, and saltwater-freshwater interface elevations in south-central Kansas were collected and analyzed using the geostatistical approach. Ordinary kriging was adopted to estimate initial conditions for ground-water levels and topography of the Permian bedrock at the nodes of a finite difference grid used in a three-dimensional numerical model. Cokriging was used to estimate initial conditions for the saltwater-freshwater interface. An assessment of uncertainties in the estimated data is presented. The kriged and cokriged estimation variances were analyzed to evaluate the adequacy of data employed in the modeling. Although water levels and bedrock elevations are well described by spherical semivariogram models, additional data are required for better cokriging estimation of the interface data. The geostatistically analyzed data were employed in a numerical model of the Siefkes site in the project area. Results indicate that the computed chloride concentrations and ground-water drawdowns reproduced the observed data satisfactorily.","largerWorkType":{"id":2,"text":"Article"},"largerWorkTitle":"Journal of Hydrologic Engineering","largerWorkSubtype":{"id":10,"text":"Journal Article"},"language":"English","publisher":"ASCE","publisherLocation":"Reston, VA, United States","doi":"10.1061/(ASCE)1084-0699(1999)4:1(57)","issn":"10840699","usgsCitation":"Ma, T., Sophocleous, M., and Yu, Y., 1999, Geostatistical applications in ground-water modeling in south-central Kansas: Journal of Hydrologic Engineering, v. 4, no. 1, p. 57-64, https://doi.org/10.1061/(ASCE)1084-0699(1999)4:1(57).","startPage":"57","endPage":"64","numberOfPages":"8","costCenters":[],"links":[{"id":229232,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"},{"id":206256,"rank":9999,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.1061/(ASCE)1084-0699(1999)4:1(57)"}],"volume":"4","issue":"1","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505a28b1e4b0c8380cd5a30e","contributors":{"authors":[{"text":"Ma, T.-S.","contributorId":67232,"corporation":false,"usgs":true,"family":"Ma","given":"T.-S.","email":"","affiliations":[],"preferred":false,"id":391957,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Sophocleous, M.","contributorId":13373,"corporation":false,"usgs":true,"family":"Sophocleous","given":"M.","email":"","affiliations":[],"preferred":false,"id":391956,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Yu, Y.-S.","contributorId":98892,"corporation":false,"usgs":true,"family":"Yu","given":"Y.-S.","email":"","affiliations":[],"preferred":false,"id":391958,"contributorType":{"id":1,"text":"Authors"},"rank":3}]}}
,{"id":70021875,"text":"70021875 - 1999 - The evolutionary history of steelhead (<i>Oncorhynchus mykiss</i>) along the US Pacific Coast: Developing a conservation strategy using genetic diversity","interactions":[],"lastModifiedDate":"2017-02-27T14:59:15","indexId":"70021875","displayToPublicDate":"1999-01-01T00:00:00","publicationYear":"1999","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1936,"text":"ICES Journal of Marine Science","active":true,"publicationSubtype":{"id":10}},"title":"The evolutionary history of steelhead (<i>Oncorhynchus mykiss</i>) along the US Pacific Coast: Developing a conservation strategy using genetic diversity","docAbstract":"<p>Changes in genetic variation across a species range may indicate patterns of population structure resulting from past ecological and demographic events that are otherwise difficult to infer and thus provide insight into evolutionary development. Genetic data is used, drawn from 11 microsatellite loci amplified from anadromous steelhead (<i>Oncorhynchus mykiss</i>) sampled throughout its range in the eastern Pacific Ocean, to explore population structure at the southern edge in California. Steelhead populations in this region represent less than 10% of their reported historic abundance and survive in very small populations found in fragmented habitats. Genetic data derived from three independent molecular systems (allozymes, mtDNA, and microsatellites) have shown that the southernmost populations are characterized by a relatively high genetic diversity. Two hypothetical models supporting genetic population substructure such as observed were considered: (1) range expansion with founder-flush effects and subsequent population decline; (2) a second Pleistocene radiation from the Gulf of California. Using genetic and climatic data, a second Pleistocene refugium contributing to a southern ecotone seems more feasible. These data support strong conservation measures based on genetic diversity be developed to ensure the survival of this uniquely diverse gene pool.</p>","language":"English","publisher":"Oxford Academic","doi":"10.1006/jmsc.1999.0452","issn":"10543139","usgsCitation":"Nielsen, J., 1999, The evolutionary history of steelhead (<i>Oncorhynchus mykiss</i>) along the US Pacific Coast: Developing a conservation strategy using genetic diversity: ICES Journal of Marine Science, v. 56, no. 4, p. 449-458, https://doi.org/10.1006/jmsc.1999.0452.","productDescription":"10 p.","startPage":"449","endPage":"458","costCenters":[{"id":114,"text":"Alaska Science Center","active":true,"usgs":true}],"links":[{"id":479649,"rank":1,"type":{"id":40,"text":"Open Access Publisher Index Page"},"url":"https://doi.org/10.1006/jmsc.1999.0452","text":"Publisher Index Page"},{"id":229530,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"country":"United States","volume":"56","issue":"4","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505babebe4b08c986b323174","contributors":{"authors":[{"text":"Nielsen, J.L.","contributorId":105665,"corporation":false,"usgs":true,"family":"Nielsen","given":"J.L.","email":"","affiliations":[],"preferred":false,"id":391517,"contributorType":{"id":1,"text":"Authors"},"rank":1}]}}
,{"id":70021926,"text":"70021926 - 1999 - Subsurface gas offshore of northern California and its link to submarine geomorphology","interactions":[],"lastModifiedDate":"2012-03-12T17:19:38","indexId":"70021926","displayToPublicDate":"1999-01-01T00:00:00","publicationYear":"1999","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":"Subsurface gas offshore of northern California and its link to submarine geomorphology","docAbstract":"The northern California continental margin contains evidence of abundant subsurface gas and numerous seafloor features that suggest a causative link between gas expulsion and geomorphology. Analyses of seismic reflection, sidescan sonar, and high-resolution multibeam bathymetric data show that the occurrence of subbottom gas and the migration processes beneath the shelf differ from those beneath the slope. Subsurface gas, inferred from enhanced reflectors and other geophysical indicators, is spatially variable and related more to total depth and stratigraphy than to underlying structure, with the exception of one band of gas that follows the regional structural trend. Shallow depressions on the seafloor (pockmarks) are used to infer expulsion sites. The largest zone of acoustically impenetrable subsurface gas occurs between water depths of 100 m and 300 m, where expulsion features are rare. The upper slope (water depths 400-600 m) has a high concentration of pockmarks (diameter 10-20 m), in contrast to a near-absence of pockmarks at water depths shallower than 400 m. Of nearly 4000 pockmarks observed on sidescan sonar records, more than 95% are located in water depths deeper than 400 m. Bottom simulating reflectors (BSRs) on some seismic reflection profiles indicate the possible presence of gas hydrate. We find that gas and pore-fluid migration in the offshore Eel River Basin is: (1) correlated to surface morphology; (2) a contributor to seabed roughness; (3) a significant mode of sediment redistribution on the upper slope; and (4) potentially a factor in large slope failures.","largerWorkType":{"id":2,"text":"Article"},"largerWorkTitle":"Marine Geology","largerWorkSubtype":{"id":10,"text":"Journal Article"},"language":"English","doi":"10.1016/S0025-3227(98)00123-6","issn":"00253227","usgsCitation":"Yun, J., Orange, D., and Field, M., 1999, Subsurface gas offshore of northern California and its link to submarine geomorphology: Marine Geology, v. 154, no. 1-4, p. 357-368, https://doi.org/10.1016/S0025-3227(98)00123-6.","startPage":"357","endPage":"368","numberOfPages":"12","costCenters":[],"links":[{"id":206320,"rank":9999,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.1016/S0025-3227(98)00123-6"},{"id":229418,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"154","issue":"1-4","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505b9d67e4b08c986b31d821","contributors":{"authors":[{"text":"Yun, J.W.","contributorId":103932,"corporation":false,"usgs":true,"family":"Yun","given":"J.W.","email":"","affiliations":[],"preferred":false,"id":391737,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Orange, D.L.","contributorId":31814,"corporation":false,"usgs":true,"family":"Orange","given":"D.L.","affiliations":[],"preferred":false,"id":391736,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Field, M.E.","contributorId":27052,"corporation":false,"usgs":true,"family":"Field","given":"M.E.","affiliations":[],"preferred":false,"id":391735,"contributorType":{"id":1,"text":"Authors"},"rank":3}]}}
,{"id":70022195,"text":"70022195 - 1999 - Long‐term trends in stream water and precipitation chemistry at five headwater basins in the northeastern United States","interactions":[],"lastModifiedDate":"2018-03-20T15:03:13","indexId":"70022195","displayToPublicDate":"1999-01-01T00:00:00","publicationYear":"1999","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":3722,"text":"Water Resources Research","onlineIssn":"1944-7973","printIssn":"0043-1397","active":true,"publicationSubtype":{"id":10}},"title":"Long‐term trends in stream water and precipitation chemistry at five headwater basins in the northeastern United States","docAbstract":"<p><span>Stream water data from five headwater basins in the northeastern United States covering water years 1968–1996 and precipitation data from eight nearby precipitation monitoring sites covering water years 1984‐1996 were analyzed for temporal trends in chemistry using the nonparametric seasonal Kendall test. Concentrations of SO</span><sub>4</sub><span>declined at three of five streams during 1968–1996 (</span><i>p</i><span><span>&nbsp;</span>&lt; 0.1), and all of the streams exhibited downward trends in SO</span><sub>4</sub><span><span>&nbsp;</span>over the second half of the period (1984–1996). Concentrations of SO</span><sub>4</sub><span><span>&nbsp;</span>in precipitation declined at seven of eight sites from 1984 to 1996, and the magnitudes of the declines (−0.7 to −2.0 µeq L</span><sup>−1</sup><span><span>&nbsp;</span>yr</span><sup>−1</sup><span>) generally were similar to those of stream water SO</span><sub>4</sub><span>. These results indicate that changes in precipitation SO</span><sub>4</sub><span><span>&nbsp;</span>were of sufficient magnitude to account for changes in stream water SO</span><sub>4</sub><span>. Concentrations of Ca + Mg declined at three of five streams and five of eight precipitation sites from 1984 to 1996. Precipitation acidity decreased at five of eight sites during the same period, but alkalinity increased in only one stream. In most cases the decreases in stream water SO</span><sub>4</sub><span><span>&nbsp;</span>were similar in magnitude to declines in stream water Ca + Mg, which is consistent with the theory of leaching by mobile acid anions in soils. In precipitation the magnitudes of SO</span><sub>4</sub><span><span>&nbsp;</span>declines were similar to those of hydrogen, and declines in Ca +Mg were much smaller. This indicates that recent decreases in SO</span><sub>4</sub><span><span>&nbsp;</span>deposition are now being reflected in reduced precipitation acidity. The lack of widespread increases in stream water alkalinity, despite the prevalence of downward trends in stream water SO</span><sub>4</sub><span>, suggests that at most sites, increases in stream water<span>&nbsp;</span></span><i>p</i><span>H and acid‐neutralizing capacity may be delayed until higher soil base‐saturation levels are achieved.</span></p>","language":"English","publisher":"American Geophysical Union","doi":"10.1029/1998WR900050","usgsCitation":"Clow, D.W., and Mast, M.A., 1999, Long‐term trends in stream water and precipitation chemistry at five headwater basins in the northeastern United States: Water Resources Research, v. 35, no. 2, p. 541-554, https://doi.org/10.1029/1998WR900050.","productDescription":"14 p.","startPage":"541","endPage":"554","costCenters":[{"id":191,"text":"Colorado Water Science Center","active":true,"usgs":true}],"links":[{"id":487375,"rank":1,"type":{"id":40,"text":"Open Access Publisher Index Page"},"url":"https://doi.org/10.1029/1998wr900050","text":"Publisher Index Page"},{"id":230330,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"35","issue":"2","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505a49ace4b0c8380cd687d4","contributors":{"authors":[{"text":"Clow, David W. 0000-0001-6183-4824 dwclow@usgs.gov","orcid":"https://orcid.org/0000-0001-6183-4824","contributorId":1671,"corporation":false,"usgs":true,"family":"Clow","given":"David","email":"dwclow@usgs.gov","middleInitial":"W.","affiliations":[{"id":191,"text":"Colorado Water Science Center","active":true,"usgs":true}],"preferred":true,"id":392678,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Mast, M. Alisa 0000-0001-6253-8162 mamast@usgs.gov","orcid":"https://orcid.org/0000-0001-6253-8162","contributorId":827,"corporation":false,"usgs":true,"family":"Mast","given":"M.","email":"mamast@usgs.gov","middleInitial":"Alisa","affiliations":[{"id":191,"text":"Colorado Water Science Center","active":true,"usgs":true}],"preferred":true,"id":392679,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}}
,{"id":70021497,"text":"70021497 - 1999 - Reassessment of ice-age cooling of the tropical ocean and atmosphere","interactions":[],"lastModifiedDate":"2012-03-12T17:19:40","indexId":"70021497","displayToPublicDate":"1999-01-01T00:00:00","publicationYear":"1999","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":2840,"text":"Nature","active":true,"publicationSubtype":{"id":10}},"title":"Reassessment of ice-age cooling of the tropical ocean and atmosphere","docAbstract":"The CLIMAP project's reconstruction of past sea surface temperature inferred limited ice-age cooling in the tropical oceans. This conclusion has been controversial, however, because of the greater cooling indicated by other terrestrial and ocean proxy data. A new faunal sea surface temperature reconstruction, calibrated using the variation of foraminiferal species through time, better represents ice-age faunal assemblages and so reveals greater cooling than CLIMAP in the equatorial current systems of the eastern Pacific and tropical Atlantic oceans. Here we explore the climatic implications of this revised sea surface temperature field for the Last Glacial Maximum using an atmospheric general circulation model. Relative to model results obtained using CLIMAP sea surface temperatures, the cooler equatorial oceans modify seasonal air temperatures by 1-2??C or more across parts of South America, Africa and southeast Asia and cause attendant changes in regional moisture patterns. In our simulation of the Last Glacial Maximum, the Amazon lowlands, for example, are cooler and drier, whereas the Andean highlands are cooler and wetter than the control simulation. Our results may help to resolve some of the apparent disagreements between oceanic and continental proxy climate data. Moreover, they suggest a wind-related mechanism for enhancing the export of water vapour from the Atlantic to the Indo-Pacific oceans, which may link variations in deep-water production and high-latitude climate changes to equatorial sea surface temperatures.","largerWorkType":{"id":2,"text":"Article"},"largerWorkTitle":"Nature","largerWorkSubtype":{"id":10,"text":"Journal Article"},"language":"English","doi":"10.1038/21401","issn":"00280836","usgsCitation":"Hostetler, S.W., and Mix, A., 1999, Reassessment of ice-age cooling of the tropical ocean and atmosphere: Nature, v. 399, no. 6737, p. 673-676, https://doi.org/10.1038/21401.","startPage":"673","endPage":"676","numberOfPages":"4","costCenters":[],"links":[{"id":206277,"rank":9999,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.1038/21401"},{"id":229281,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"399","issue":"6737","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505a95bee4b0c8380cd81bee","contributors":{"authors":[{"text":"Hostetler, S. W. 0000-0003-2272-8302","orcid":"https://orcid.org/0000-0003-2272-8302","contributorId":42911,"corporation":false,"usgs":true,"family":"Hostetler","given":"S.","email":"","middleInitial":"W.","affiliations":[],"preferred":false,"id":390085,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Mix, A.C.","contributorId":31139,"corporation":false,"usgs":true,"family":"Mix","given":"A.C.","email":"","affiliations":[],"preferred":false,"id":390084,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}}
,{"id":70021236,"text":"70021236 - 1999 - Age and thermal history of the Geysers plutonic complex (felsite unit), Geysers geothermal field, California: A 40Ar/39Ar and U-Pb study","interactions":[],"lastModifiedDate":"2012-03-12T17:19:40","indexId":"70021236","displayToPublicDate":"1999-01-01T00:00:00","publicationYear":"1999","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1427,"text":"Earth and Planetary Science Letters","active":true,"publicationSubtype":{"id":10}},"title":"Age and thermal history of the Geysers plutonic complex (felsite unit), Geysers geothermal field, California: A 40Ar/39Ar and U-Pb study","docAbstract":"Sixty-nine ion microprobe spot analyses of zircons from four granite samples from the plutonic complex that underlies the Geysers geothermal field yield 207Pb/206Pb vs. 238U/206Pb concordia ages ranging from 1.13 ?? 0.04 Ma to 1.25 ?? 0.04 (1??) Ma. The weighted mean of the U/Pb model ages is 1.18 ?? 0.03 Ma. The U-Pb ages coincide closely with 40Ar/39Ar age spectrum plateau and 'terminal' ages from coexisting K-feldspars and with the eruption ages of overlying volcanic rocks. The data indicate that the granite crystallized at 1.18 Ma and had cooled below 350??C by ~0.9-1.0 Ma. Interpretation of the feldspar 40Ar/39Ar age data using multi-diffusion domain theory indicates that post-emplacement rapid cooling was succeeded either by slower cooling from 350??to 300??C between 1.0 and 0.4 Ma or transitory reheating to 300-350??C at about 0.4-0.6 Ma. Subsequent rapid cooling to below 260??C between 0.4 and 0.2 Ma is in agreement with previous proposals that vapor-dominated conditions were initiated within the hydrothermal system at this time. Heat flow calculations constrained with K-feldspar thermal histories and the present elevated regional heat flow anomaly demonstrate that appreciable heat input from sources external to the known Geysers plutonic complex is required to maintain the geothermal system. This requirement is satisfied by either a large, underlying, convecting magma chamber (now solidified) emplaced at 1.2 Ma or episodic intrusion of smaller bodies from 1.2 to 0.6 Ma.","largerWorkType":{"id":2,"text":"Article"},"largerWorkTitle":"Earth and Planetary Science Letters","largerWorkSubtype":{"id":10,"text":"Journal Article"},"language":"English","doi":"10.1016/S0012-821X(99)00223-X","issn":"0012821X","usgsCitation":"Dalrymple, G.B., Grove, M., Lovera, O., Harrison, T., Hulen, J.B., and Lanphere, M.A., 1999, Age and thermal history of the Geysers plutonic complex (felsite unit), Geysers geothermal field, California: A 40Ar/39Ar and U-Pb study: Earth and Planetary Science Letters, v. 173, no. 3, p. 285-298, https://doi.org/10.1016/S0012-821X(99)00223-X.","startPage":"285","endPage":"298","numberOfPages":"14","costCenters":[],"links":[{"id":229704,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"},{"id":206423,"rank":9999,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.1016/S0012-821X(99)00223-X"}],"volume":"173","issue":"3","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"5059e8e4e4b0c8380cd47f55","contributors":{"authors":[{"text":"Dalrymple, G. B.","contributorId":10407,"corporation":false,"usgs":true,"family":"Dalrymple","given":"G.","email":"","middleInitial":"B.","affiliations":[],"preferred":false,"id":389158,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Grove, M.","contributorId":65271,"corporation":false,"usgs":true,"family":"Grove","given":"M.","email":"","affiliations":[],"preferred":false,"id":389163,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Lovera, O.M.","contributorId":37212,"corporation":false,"usgs":true,"family":"Lovera","given":"O.M.","affiliations":[],"preferred":false,"id":389160,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Harrison, T.M.","contributorId":60788,"corporation":false,"usgs":true,"family":"Harrison","given":"T.M.","email":"","affiliations":[],"preferred":false,"id":389162,"contributorType":{"id":1,"text":"Authors"},"rank":4},{"text":"Hulen, J. B.","contributorId":44183,"corporation":false,"usgs":true,"family":"Hulen","given":"J.","email":"","middleInitial":"B.","affiliations":[],"preferred":false,"id":389161,"contributorType":{"id":1,"text":"Authors"},"rank":5},{"text":"Lanphere, M. A.","contributorId":35298,"corporation":false,"usgs":true,"family":"Lanphere","given":"M.","email":"","middleInitial":"A.","affiliations":[],"preferred":false,"id":389159,"contributorType":{"id":1,"text":"Authors"},"rank":6}]}}
,{"id":70186547,"text":"70186547 - 1999 - Comparison of aerial survey procedures for estimating polar bear density: Results of pilot studies in northern Alaska","interactions":[{"subject":{"id":70186547,"text":"70186547 - 1999 - Comparison of aerial survey procedures for estimating polar bear density: Results of pilot studies in northern Alaska","indexId":"70186547","publicationYear":"1999","noYear":false,"title":"Comparison of aerial survey procedures for estimating polar bear density: Results of pilot studies in northern Alaska"},"predicate":"IS_PART_OF","object":{"id":70180186,"text":"70180186 - 1999 - Marine mammal survey and assessment methods","indexId":"70180186","publicationYear":"1999","noYear":false,"title":"Marine mammal survey and assessment methods"},"id":1}],"isPartOf":{"id":70180186,"text":"70180186 - 1999 - Marine mammal survey and assessment methods","indexId":"70180186","publicationYear":"1999","noYear":false,"title":"Marine mammal survey and assessment methods"},"lastModifiedDate":"2017-04-06T16:04:24","indexId":"70186547","displayToPublicDate":"1999-01-01T00:00:00","publicationYear":"1999","noYear":false,"publicationType":{"id":24,"text":"Conference Paper"},"publicationSubtype":{"id":19,"text":"Conference Paper"},"title":"Comparison of aerial survey procedures for estimating polar bear density: Results of pilot studies in northern Alaska","docAbstract":"<p><span>The U.S. Marine Mammal Protection Act (MMPA) and International Agreement on the Conservation of Polar Bears mandate that boundaries and sizes of polar bear (</span><i><span>Ursus maritimus</span></i><span>) populations be known so they can be managed at optimum sustainable levels. However, data to estimate polar bear numbers for the Chukchi/Bering Sea and Beaufort Sea populations in Alaska are limited. We evaluated aerial line transect methodology for assessing the size of these Alaskan polar bear populations during pilot studies in spring 1987 and summer 1994. In April and May 1987 we flew 12.239 km of transect lines in the northern Bering, Chukchi, and western Beaufort seas. In June 1994 we flew 6.244 km of transect lines in a primary survey unit using a helicopter, and 5,701 km of transect lines in a secondary survey unit using a fixed-wing aircraft in the Beaufort Sea. We examined visibility bias in aerial transect surveys, double counts by independent observers, single-season mark-resight methods, the suitability of using polar bear sign to stratify the study area, and adaptive sampling methods. Fifteen polar bear groups were observed during the 1987 study. Probability of detecting bears decreased with increasing perpendicular distance from the transect line, and probability of detecting polar bear groups likely increased with increasing group size. We estimated population density in high density areas to be 446 km<sup>2</sup>/bear. In 1994, 15 polar bear groups were observed by independent front and rear seat observers on transect lines in the primary survey unit. Density estimates ranged from 284 km<sup>2</sup>/bear to 197 km<sup>2</sup>/bear depending on the model selected. Low polar bear numbers scattered over large areas of polar ice in 1987 indicated that spring is a poor time to conduct aerial surveys. Based on the 1994 survey we determined that ship-based helicopter or land-based fixed-wing aerial surveys conducted at the ice-edge in late summer-early fall may produce robust density estimates for polar bear populations in the Chukchi/Bering and Beaufort seas.</span></p>","largerWorkType":{"id":4,"text":"Book"},"largerWorkTitle":"Marine mammal survey and assessment methods","largerWorkSubtype":{"id":12,"text":"Conference publication"},"conferenceTitle":"Symposium on surveys, status & trends of marine mammal populations","conferenceDate":"25-27 February, 1998","conferenceLocation":"Seattle, WA","language":"English","publisher":"A.A. Balkema","publisherLocation":"Rotterdam, Netherlands","isbn":"9789058090430","usgsCitation":"McDonald, L.L., and Garner, G.W., 1999, Comparison of aerial survey procedures for estimating polar bear density: Results of pilot studies in northern Alaska, <i>in</i> Marine mammal survey and assessment methods, Seattle, WA, 25-27 February, 1998, p. 37-52.","productDescription":"16 p.","startPage":"37","endPage":"52","costCenters":[{"id":114,"text":"Alaska Science Center","active":true,"usgs":true}],"links":[{"id":339215,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"},{"id":339214,"rank":1,"type":{"id":15,"text":"Index Page"},"url":"https://www.crcpress.com/Marine-Mammal-Survey-and-Assessment-Methods/Laake-Robertson-Amstrup/p/book/9789058090430"}],"noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"58e60275e4b09da6799ac697","contributors":{"editors":[{"text":"Garner, Gerald W.","contributorId":149918,"corporation":false,"usgs":false,"family":"Garner","given":"Gerald","email":"","middleInitial":"W.","affiliations":[{"id":13117,"text":"Institute of Arctic Biology, University of Alaska Fairbanks","active":true,"usgs":false}],"preferred":false,"id":688730,"contributorType":{"id":2,"text":"Editors"},"rank":1},{"text":"Amstrup, Steven C.","contributorId":67034,"corporation":false,"usgs":false,"family":"Amstrup","given":"Steven","email":"","middleInitial":"C.","affiliations":[{"id":13182,"text":"Polar Bears International","active":true,"usgs":false}],"preferred":false,"id":688731,"contributorType":{"id":2,"text":"Editors"},"rank":2},{"text":"Laake, Jeffrey L.","contributorId":83851,"corporation":false,"usgs":false,"family":"Laake","given":"Jeffrey","email":"","middleInitial":"L.","affiliations":[{"id":6578,"text":"National Marine Fisheries Service, Seattle, WA 98112, USA","active":true,"usgs":false}],"preferred":false,"id":688732,"contributorType":{"id":2,"text":"Editors"},"rank":3},{"text":"Manly, Bryan F.J.","contributorId":41770,"corporation":false,"usgs":true,"family":"Manly","given":"Bryan","email":"","middleInitial":"F.J.","affiliations":[],"preferred":false,"id":688734,"contributorType":{"id":2,"text":"Editors"},"rank":4},{"text":"McDonald, Lyman L.","contributorId":14939,"corporation":false,"usgs":true,"family":"McDonald","given":"Lyman","email":"","middleInitial":"L.","affiliations":[],"preferred":false,"id":688733,"contributorType":{"id":2,"text":"Editors"},"rank":5},{"text":"Robertson, Donna G.","contributorId":29965,"corporation":false,"usgs":true,"family":"Robertson","given":"Donna","email":"","middleInitial":"G.","affiliations":[],"preferred":false,"id":688735,"contributorType":{"id":2,"text":"Editors"},"rank":6}],"authors":[{"text":"McDonald, Lyman L.","contributorId":14939,"corporation":false,"usgs":true,"family":"McDonald","given":"Lyman","email":"","middleInitial":"L.","affiliations":[],"preferred":false,"id":688728,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Garner, Gerald W.","contributorId":149918,"corporation":false,"usgs":false,"family":"Garner","given":"Gerald","email":"","middleInitial":"W.","affiliations":[{"id":13117,"text":"Institute of Arctic Biology, University of Alaska Fairbanks","active":true,"usgs":false}],"preferred":false,"id":688729,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}}
,{"id":70021752,"text":"70021752 - 1999 - Geotechnical characteristics and slope stability in the Gulf of Cadiz","interactions":[],"lastModifiedDate":"2012-03-12T17:19:37","indexId":"70021752","displayToPublicDate":"1999-01-01T00:00:00","publicationYear":"1999","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":"Geotechnical characteristics and slope stability in the Gulf of Cadiz","docAbstract":"Sedimentological and geotechnical analyses of thirty-seven core samples from the Gulf of Cadiz continental margin were used to define the regional variability of sediment properties and to assess slope stability. Considering the sediment property data set as a whole, there is an association between grain size, plasticity and water content. Any one of these properties can be mapped regionally to provide an indication of the dominant surface sediment lithology. Based on static sediment strength, a simplified slope stability analysis showed that only steep slopes (> 16??for even the most vulnerable sediment) can fail under static loading conditions. Accordingly, transient loads, such as earthquakes or storms, are needed to cause failure on more moderate slopes. A regional seismic slope stability analysis of the Cadiz margin was performed based on detailed geotechnical testing of four gravity core samples. The results showed that the stability of these slopes under seismic loading conditions depends upon sediment density, the cyclic loading shear strength, the slope steepness, and the regional seismicity. Sediment density and cyclic loading shear strength are dependent upon water content, which can act as a proxy for plasticity and texture effects. Specifically, Sediment in the water content range of 50-56% is most vulnerable to failure under cyclic loading within the Cadiz margin. As a result, for a uniform seismicity over the region, susceptibility to failure during seismic loading conditions increases with increasing slope steepness and is higher if the sediment water content is in the 50-56% range than if it is not. The only sampled zone of failure on the continental slope contains sediment with water content in this critical range. Storm-wave-induced instability was evaluated for the continental shelf. The evaluation showed that a storm having hundreds of waves with a height in the range of 16 m might be capable of causing failure on the shelf. However, no sediment failures were observed on the shelf that might have been caused by this mechanism.","largerWorkType":{"id":2,"text":"Article"},"largerWorkTitle":"Marine Geology","largerWorkSubtype":{"id":10,"text":"Journal Article"},"language":"English","doi":"10.1016/S0025-3227(98)00146-7","issn":"00253227","usgsCitation":"Lee, H., and Baraza, J., 1999, Geotechnical characteristics and slope stability in the Gulf of Cadiz: Marine Geology, v. 155, no. 1-2, p. 173-190, https://doi.org/10.1016/S0025-3227(98)00146-7.","startPage":"173","endPage":"190","numberOfPages":"18","costCenters":[],"links":[{"id":229262,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"},{"id":206265,"rank":9999,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.1016/S0025-3227(98)00146-7"}],"volume":"155","issue":"1-2","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505a28b5e4b0c8380cd5a33c","contributors":{"authors":[{"text":"Lee, H.","contributorId":40739,"corporation":false,"usgs":true,"family":"Lee","given":"H.","affiliations":[],"preferred":false,"id":391015,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Baraza, J.","contributorId":12200,"corporation":false,"usgs":true,"family":"Baraza","given":"J.","email":"","affiliations":[],"preferred":false,"id":391014,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}}
,{"id":70021734,"text":"70021734 - 1999 - A sampling plan for conduit-flow karst springs: Minimizing sampling cost and maximizing statistical utility","interactions":[],"lastModifiedDate":"2012-03-12T17:19:41","indexId":"70021734","displayToPublicDate":"1999-01-01T00:00:00","publicationYear":"1999","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1517,"text":"Engineering Geology","active":true,"publicationSubtype":{"id":10}},"title":"A sampling plan for conduit-flow karst springs: Minimizing sampling cost and maximizing statistical utility","docAbstract":"Analytical data for nitrate and triazines from 566 samples collected over a 3-year period at Pleasant Grove Spring, Logan County, KY, were statistically analyzed to determine the minimum data set needed to calculate meaningful yearly averages for a conduit-flow karst spring. Results indicate that a biweekly sampling schedule augmented with bihourly samples from high-flow events will provide meaningful suspended-constituent and dissolved-constituent statistics. Unless collected over an extensive period of time, daily samples may not be representative and may also be autocorrelated. All high-flow events resulting in a significant deflection of a constituent from base-line concentrations should be sampled. Either the geometric mean or the flow-weighted average of the suspended constituents should be used. If automatic samplers are used, then they may be programmed to collect storm samples as frequently as every few minutes to provide details on the arrival time of constituents of interest. However, only samples collected bihourly should be used to calculate averages. By adopting a biweekly sampling schedule augmented with high-flow samples, the need to continuously monitor discharge, or to search for and analyze existing data to develop a statistically valid monitoring plan, is lessened.Analytical data for nitrate and triazines from 566 samples collected over a 3-year period at Pleasant Grove Spring, Logan County, KY, were statistically analyzed to determine the minimum data set needed to calculate meaningful yearly averages for a conduit-flow karst spring. Results indicate that a biweekly sampling schedule augmented with bihourly samples from high-flow events will provide meaningful suspended-constituent and dissolved-constituent statistics. Unless collected over an extensive period of time, daily samples may not be representative and may also be autocorrelated. All high-flow events resulting in a significant deflection of a constituent from base-line concentrations should be sampled. Either the geometric mean or the flow-weighted average of the suspended constituents should be used. If automatic samplers are used, then they may be programmed to collect storm samples as frequently as every few minutes to provide details on the arrival time of constituents of interest. However, only samples collected bihourly should be used to calculate averages. By adopting a biweekly sampling schedule augmented with high-flow samples, the need to continuously monitor discharge, or to search for and analyze existing data to develop a statistically valid monitoring plan, is lessened.","largerWorkType":{"id":2,"text":"Article"},"largerWorkTitle":"Engineering Geology","largerWorkSubtype":{"id":10,"text":"Journal Article"},"language":"English","publisher":"Elsevier Science Publishers B.V.","publisherLocation":"Amsterdam, Netherlands","doi":"10.1016/S0013-7952(98)00064-7","issn":"00137952","usgsCitation":"Currens, J., 1999, A sampling plan for conduit-flow karst springs: Minimizing sampling cost and maximizing statistical utility: Engineering Geology, v. 52, no. 1-2, p. 121-128, https://doi.org/10.1016/S0013-7952(98)00064-7.","startPage":"121","endPage":"128","numberOfPages":"8","costCenters":[],"links":[{"id":229521,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"},{"id":206357,"rank":9999,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.1016/S0013-7952(98)00064-7"}],"volume":"52","issue":"1-2","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"5059e569e4b0c8380cd46d4e","contributors":{"authors":[{"text":"Currens, J.C.","contributorId":72036,"corporation":false,"usgs":true,"family":"Currens","given":"J.C.","email":"","affiliations":[],"preferred":false,"id":390954,"contributorType":{"id":1,"text":"Authors"},"rank":1}]}}
,{"id":70021733,"text":"70021733 - 1999 - Site response for Seattle and source parameters of earthquakes in the Puget Sound Region","interactions":[],"lastModifiedDate":"2023-10-18T00:47:17.100688","indexId":"70021733","displayToPublicDate":"1999-01-01T00:00:00","publicationYear":"1999","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1135,"text":"Bulletin of the Seismological Society of America","onlineIssn":"1943-3573","printIssn":"0037-1106","active":true,"publicationSubtype":{"id":10}},"title":"Site response for Seattle and source parameters of earthquakes in the Puget Sound Region","docAbstract":"<div id=\"134904764\" class=\"article-section-wrapper js-article-section js-content-section  \" data-section-parent-id=\"0\"><p>We analyzed seismograms from 21 earthquakes (<i>M<sub>L</sub></i><span>&nbsp;</span>2.0-4.9) recorded by digital seismographs we deployed in urban Seattle to determine site response and earthquake stress drops. The seismometers were situated on a wide variety of geologic units, including artificial fill (e.g., Kingdome, Harbor Island), Pleistocene age soils (glacial till and outwash deposits of Seattle's hills), modified land (downtown Seattle, Space Needle), and Tertiary sedimentary rock. Two mainshock-aftershock sequences were recorded: the June 1997 Bremerton sequence (mainshock<span>&nbsp;</span><i>M<sub>L</sub></i><span>&nbsp;</span>4.9) and the February 1997 South Seattle sequence (mainshock<span>&nbsp;</span><i>M<sub>L</sub></i><span>&nbsp;</span>3.5), along with other events in the Puget Sound region. We developed a new inversion procedure to estimate site response, source corner frequencies, and seismic moments from the<span>&nbsp;</span><i>S</i>-wave spectra. This inversion uses corner frequencies determined from spectral ratios of mainshock-aftershock pairs as constraints. The site responses found from the inversion are not relative to the rock site but are relative to an idealized site with a flat frequency response. The response of the rock site is also found from the inversion. The inversion results show high response for the sites on artificial fill, more moderate amplification for most sites on stiff Pleistocene soils or modified land, and low response for the rock site. Some sites display resonances, such as a strong 2-Hz resonance at our site near the Kingdome, which is caused by the surficial layers of fill and younger alluvium. The sites in West Seattle exhibit high amplification, even though they are on relatively stiff soils of glacial outwash. This may be partly caused by basin surface waves produced by conversion of incident<span>&nbsp;</span><i>S</i><span>&nbsp;</span>waves. This high response in West Seattle is consistent with damage reports from the 1949 (<i>m<sub>b</sub></i><span>&nbsp;</span>7.1) and 1965 (<i>m<sub>b</sub></i><span>&nbsp;</span>6.5) earthquakes. Stress-drop estimates for the events we recorded were generally low, between 0.4 and 25 bars, although some of the events may have had higher stress drops that could not be resolved because of the limited passband. We calculated a stress drop of 24 bars for the Bremerton mainshock and 10 bars for the South Seattle mainshock.</p></div>","language":"English","publisher":"Seismological Society of America","doi":"10.1785/BSSA0890020468","issn":"00371106","usgsCitation":"Frankel, A., Carver, D., Cranswick, E., Meremonte, M., Bice, T., and Overturf, D., 1999, Site response for Seattle and source parameters of earthquakes in the Puget Sound Region: Bulletin of the Seismological Society of America, v. 89, no. 2, p. 468-483, https://doi.org/10.1785/BSSA0890020468.","productDescription":"16 p.","startPage":"468","endPage":"483","numberOfPages":"16","costCenters":[],"links":[{"id":229520,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"country":"United States","state":"Washington","otherGeospatial":"Puget Sound Region","geographicExtents":"{\n  \"type\": \"FeatureCollection\",\n  \"features\": [\n    {\n      \"type\": \"Feature\",\n      \"properties\": {},\n      \"geometry\": {\n        \"coordinates\": [\n          [\n            [\n              -122.52533897944195,\n              47.75865223343823\n            ],\n            [\n              -122.52533897944195,\n              47.4689028364341\n            ],\n            [\n              -122.0988280442098,\n              47.4689028364341\n            ],\n            [\n              -122.0988280442098,\n              47.75865223343823\n            ],\n            [\n              -122.52533897944195,\n              47.75865223343823\n            ]\n          ]\n        ],\n        \"type\": \"Polygon\"\n      }\n    }\n  ]\n}","volume":"89","issue":"2","noUsgsAuthors":false,"publicationDate":"1999-04-01","publicationStatus":"PW","scienceBaseUri":"505b90f6e4b08c986b319705","contributors":{"authors":[{"text":"Frankel, A. 0000-0001-9119-6106","orcid":"https://orcid.org/0000-0001-9119-6106","contributorId":41593,"corporation":false,"usgs":true,"family":"Frankel","given":"A.","affiliations":[],"preferred":false,"id":390951,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Carver, D.","contributorId":22792,"corporation":false,"usgs":true,"family":"Carver","given":"D.","affiliations":[],"preferred":false,"id":390948,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Cranswick, E.","contributorId":85948,"corporation":false,"usgs":true,"family":"Cranswick","given":"E.","affiliations":[],"preferred":false,"id":390953,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Meremonte, M.","contributorId":22915,"corporation":false,"usgs":true,"family":"Meremonte","given":"M.","affiliations":[],"preferred":false,"id":390949,"contributorType":{"id":1,"text":"Authors"},"rank":4},{"text":"Bice, T.","contributorId":37398,"corporation":false,"usgs":true,"family":"Bice","given":"T.","email":"","affiliations":[],"preferred":false,"id":390950,"contributorType":{"id":1,"text":"Authors"},"rank":5},{"text":"Overturf, D.","contributorId":56822,"corporation":false,"usgs":true,"family":"Overturf","given":"D.","email":"","affiliations":[],"preferred":false,"id":390952,"contributorType":{"id":1,"text":"Authors"},"rank":6}]}}
,{"id":70021730,"text":"70021730 - 1999 - The thin hot plume beneath Iceland","interactions":[],"lastModifiedDate":"2012-03-12T17:19:41","indexId":"70021730","displayToPublicDate":"1999-01-01T00:00:00","publicationYear":"1999","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1803,"text":"Geophysical Journal International","active":true,"publicationSubtype":{"id":10}},"title":"The thin hot plume beneath Iceland","docAbstract":"We present the results of a seismological investigation of the frequency-dependent amplitude variations across Iceland using data from the HOTSPOT array currently deployed there. The array is composed of 30 broad-band PASSCAL instruments. We use the parameter t(*), defined in the usual manner from spectral ratios (Halderman and Davis 1991), to compare observed S-wave amplitude variations with those predicted due to both anelastic attenuation and diffraction effects. Four teleseismic events at a range of azimuths are used to measure t(*). A 2-D vertical cylindrical plume model with a Gaussian-shaped velocity anomaly is used to model the variations. That part of t(*) caused by attenuation was estimated by tracing a ray through IASP91, then superimposing our plume model velocity anomaly and calculating the path integral of 1/vQ. That part of t(*) caused by diffraction was estimated using a 2-D finite difference code to generate synthetic seismograms. The same spectral ratio technique used for the data was then used to extract a predicted t(*). The t(*) variations caused by anelastic attenuation are unable to account for the variations we observe, but those caused by diffraction do. We calculate the t(*) variations caused by diffraction for different plume models and obtain our best-fit plume, which exhibits good agreement between the observed and measured t(*). The best-fit plume model has a maximum S-velocity anomaly of - 12 per cent and falls to 1/e of its maximum at 100 km from the plume centre. This is narrower than previous estimates from seismic tomography, which are broadened and damped by the methods of tomography. This velocity model would suggest greater ray theoretical traveltime delays than observed. However, we find that for such a plume, wave-front healing effects at frequencies of 0.03-0.175 Hz (the frequency range used to pick S-wave arrivals) causes a 40 per cent reduction in traveltime delay, reducing the ray theoretical delay to that observed.","largerWorkType":{"id":2,"text":"Article"},"largerWorkTitle":"Geophysical Journal International","largerWorkSubtype":{"id":10,"text":"Journal Article"},"language":"English","doi":"10.1046/j.1365-246X.1999.00753.x","issn":"0956540X","usgsCitation":"Allen, R.M., Nolet, G., Morgan, W.J., Vogfjord, K., Bergsson, B.H., Erlendsson, P., Foulger, G., Jakobsdottir, S., Julian, B., Pritchard, M., Ragnarsson, S., and Stefansson, R., 1999, The thin hot plume beneath Iceland: Geophysical Journal International, v. 137, no. 1, p. 51-63, https://doi.org/10.1046/j.1365-246X.1999.00753.x.","startPage":"51","endPage":"63","numberOfPages":"13","costCenters":[],"links":[{"id":487409,"rank":10000,"type":{"id":40,"text":"Open Access Publisher Index Page"},"url":"https://doi.org/10.1046/j.1365-246x.1999.00753.x","text":"Publisher Index Page"},{"id":206331,"rank":9999,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.1046/j.1365-246X.1999.00753.x"},{"id":229441,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"137","issue":"1","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505bb0fae4b08c986b325185","contributors":{"authors":[{"text":"Allen, R. M.","contributorId":36170,"corporation":false,"usgs":false,"family":"Allen","given":"R.","email":"","middleInitial":"M.","affiliations":[],"preferred":false,"id":390936,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Nolet, G.","contributorId":26448,"corporation":false,"usgs":true,"family":"Nolet","given":"G.","email":"","affiliations":[],"preferred":false,"id":390935,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Morgan, W. J.","contributorId":10573,"corporation":false,"usgs":false,"family":"Morgan","given":"W.","email":"","middleInitial":"J.","affiliations":[],"preferred":false,"id":390929,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Vogfjord, K.","contributorId":13768,"corporation":false,"usgs":true,"family":"Vogfjord","given":"K.","email":"","affiliations":[],"preferred":false,"id":390932,"contributorType":{"id":1,"text":"Authors"},"rank":4},{"text":"Bergsson, B. H.","contributorId":19320,"corporation":false,"usgs":false,"family":"Bergsson","given":"B.","email":"","middleInitial":"H.","affiliations":[],"preferred":false,"id":390934,"contributorType":{"id":1,"text":"Authors"},"rank":5},{"text":"Erlendsson, P.","contributorId":95638,"corporation":false,"usgs":true,"family":"Erlendsson","given":"P.","email":"","affiliations":[],"preferred":false,"id":390939,"contributorType":{"id":1,"text":"Authors"},"rank":6},{"text":"Foulger, G.R.","contributorId":14439,"corporation":false,"usgs":false,"family":"Foulger","given":"G.R.","email":"","affiliations":[],"preferred":false,"id":390933,"contributorType":{"id":1,"text":"Authors"},"rank":7},{"text":"Jakobsdottir, S.","contributorId":64828,"corporation":false,"usgs":true,"family":"Jakobsdottir","given":"S.","email":"","affiliations":[],"preferred":false,"id":390937,"contributorType":{"id":1,"text":"Authors"},"rank":8},{"text":"Julian, B.R.","contributorId":101272,"corporation":false,"usgs":true,"family":"Julian","given":"B.R.","email":"","affiliations":[],"preferred":false,"id":390940,"contributorType":{"id":1,"text":"Authors"},"rank":9},{"text":"Pritchard, M.","contributorId":11358,"corporation":false,"usgs":true,"family":"Pritchard","given":"M.","affiliations":[],"preferred":false,"id":390930,"contributorType":{"id":1,"text":"Authors"},"rank":10},{"text":"Ragnarsson, S.","contributorId":12644,"corporation":false,"usgs":true,"family":"Ragnarsson","given":"S.","email":"","affiliations":[],"preferred":false,"id":390931,"contributorType":{"id":1,"text":"Authors"},"rank":11},{"text":"Stefansson, R.","contributorId":81650,"corporation":false,"usgs":true,"family":"Stefansson","given":"R.","email":"","affiliations":[],"preferred":false,"id":390938,"contributorType":{"id":1,"text":"Authors"},"rank":12}]}}
,{"id":70021728,"text":"70021728 - 1999 - Reef and nonreef aquifers - A comparison of hydrogeology and geochemistry, northwestern Indiana","interactions":[],"lastModifiedDate":"2024-03-07T00:58:55.179932","indexId":"70021728","displayToPublicDate":"1999-01-01T00:00:00","publicationYear":"1999","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":3825,"text":"Groundwater","active":true,"publicationSubtype":{"id":10}},"title":"Reef and nonreef aquifers - A comparison of hydrogeology and geochemistry, northwestern Indiana","docAbstract":"<div class=\"abstract-group \"><div class=\"article-section__content en main\"><p>The principal bedrock aquifer system across much of Indiana consists of carbonate rocks of Silurian and Devonian age. The Silurian-Devonian aquifer system is used extensively for irrigation in northwestern Indiana and is approximately 170 m thick. Reef and nonreef carbonate aquifers in northwestern Indiana were assessed using hydrogeology (lithology, geophysical logs, aquifer tests) and geochemistry (major ions and stable isotopes).</p><p>The study showed differences in water quantity and quality between the reef and nonreef aquifers. The reef aquifer had few shales, abundant fossiliferous material (up to 100 m thick), and high porosities (10 to 15%). The nonreef aquifer had abundant shales, less fossiliferous material (a few meters thick), and low porosities. Total transmissivities at the reef sites were 697 m<sup>2</sup>/d, (meters squared per day) and 4831 m<sup>2</sup>/d, compared to 46 m<sup>2</sup>/d at the nonreef site. Flowpaths in the nonreef aquifer were associated with fractures and poorly connected moldic porosity with larger fractures and better connected vuggy porosity in the reef aquifer. Water chemistry data for the nonreef aquifer showed mean concentrations of sodium (235 mg/L [milligrams per liter]), sulfate (160 mg/L), sul-fide (13 mg/L), fluoride (2.7 mg/L), and dissolved solids (635 mg/L) approximately two to five times larger when compared to mean concentrations in the reef aquifer. Ground water at the nonreef site was classified as a sodium-bicarbonate type while that at the reef sites was calcium-magnesium bicarbonate. The oxygen/deuterium isotope data indicates recharge from modern precipitation and not Pleistocene-age recharge.</p></div></div>","language":"English","publisher":"National Groundwater Association","doi":"10.1111/j.1745-6584.1999.tb00974.x","issn":"0017467X","usgsCitation":"Schnoebelen, D., and Krothe, N., 1999, Reef and nonreef aquifers - A comparison of hydrogeology and geochemistry, northwestern Indiana: Groundwater, v. 37, no. 2, p. 194-203, https://doi.org/10.1111/j.1745-6584.1999.tb00974.x.","productDescription":"10 p.","startPage":"194","endPage":"203","numberOfPages":"10","costCenters":[],"links":[{"id":229402,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"37","issue":"2","noUsgsAuthors":false,"publicationDate":"2005-08-04","publicationStatus":"PW","scienceBaseUri":"50e4a417e4b0e8fec6cdba3b","contributors":{"authors":[{"text":"Schnoebelen, D.J.","contributorId":98352,"corporation":false,"usgs":true,"family":"Schnoebelen","given":"D.J.","affiliations":[],"preferred":false,"id":390925,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Krothe, N.C.","contributorId":76378,"corporation":false,"usgs":true,"family":"Krothe","given":"N.C.","affiliations":[],"preferred":false,"id":390924,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}}
,{"id":70021671,"text":"70021671 - 1999 - The role of adaptive management as an operational approach for resource management agencies","interactions":[],"lastModifiedDate":"2012-03-12T17:19:41","indexId":"70021671","displayToPublicDate":"1999-01-01T00:00:00","publicationYear":"1999","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1323,"text":"Conservation Ecology","active":true,"publicationSubtype":{"id":10}},"title":"The role of adaptive management as an operational approach for resource management agencies","docAbstract":"In making resource management decisions, agencies use a variety of approaches that involve different levels of political concern, historical precedence, data analyses, and evaluation. Traditional decision-making approaches have often failed to achieve objectives for complex problems in large systems, such as the Everglades or the Colorado River. I contend that adaptive management is the best approach available to agencies for addressing this type of complex problem, although its success has been limited thus far. Traditional decision-making approaches have been fairly successful at addressing relatively straightforward problems in small, replicated systems, such as management of trout in small streams or pulp production in forests. However, this success may be jeopardized as more users place increasing demands on these systems. Adaptive management has received little attention from agencies for addressing problems in small-scale systems, but I suggest that it may be a useful approach for creating a holistic view of common problems and developing guidelines that can then be used in simpler, more traditional approaches to management. Although adaptive management may be more expensive to initiate than traditional approaches, it may be less expensive in the long run if it leads to more effective management. The overall goal of adaptive management is not to maintain an optimal condition of the resource, but to develop an optimal management capacity. This is accomplished by maintaining ecological resilience that allows the system to react to inevitable stresses, and generating flexibility in institutions and stakeholders that allows managers to react when conditions change. The result is that, rather than managing for a single, optimal state, we manage within a range of acceptable outcomes while avoiding catastrophes and irreversible negative effects. Copyright ?? 1999 by The Resilience Alliance.","largerWorkType":{"id":2,"text":"Article"},"largerWorkTitle":"Conservation Ecology","largerWorkSubtype":{"id":10,"text":"Journal Article"},"language":"English","issn":"11955449","usgsCitation":"Johnson, B., 1999, The role of adaptive management as an operational approach for resource management agencies: Conservation Ecology, v. 3, no. 2.","costCenters":[],"links":[{"id":229589,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"3","issue":"2","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505baf4ee4b08c986b3246d3","contributors":{"authors":[{"text":"Johnson, Barry L.","contributorId":95009,"corporation":false,"usgs":true,"family":"Johnson","given":"Barry L.","affiliations":[],"preferred":false,"id":390665,"contributorType":{"id":1,"text":"Authors"},"rank":1}]}}
,{"id":70021663,"text":"70021663 - 1999 - Development of a comprehensive watershed model applied to study stream yield under drought conditions","interactions":[],"lastModifiedDate":"2024-03-07T00:59:48.110763","indexId":"70021663","displayToPublicDate":"1999-01-01T00:00:00","publicationYear":"1999","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":3825,"text":"Groundwater","active":true,"publicationSubtype":{"id":10}},"title":"Development of a comprehensive watershed model applied to study stream yield under drought conditions","docAbstract":"<div class=\"abstract-group  metis-abstract\"><div class=\"article-section__content en main\"><p>We developed a model code to simulate a watershed's hydrology and the hydraulic response of an interconnected stream-aquifer system, and applied the model code to the Lower Republican River Basin in Kansas. The model code links two well-known computer programs: MODFLOW (modular 3-D flow model), which simulates ground water flow and stream-aquifer interaction; and SWAT (soil water assessment tool), a soil water budget simulator for an agricultural watershed. SWAT represents a basin as a collection of subbasins in terms of soil, land use, and weather data, and simulates each subbasin on a daily basis to determine runoff, percolation, evaporation, irrigation, pond seepage, and crop growth. Because SWAT applies a lumped hydrologic model to each sub-basin, spatial heterogeneities with respect to factors such as soil type and land use are not resolved geographically, but can instead be represented statistically. For the Republican River Basin model, each combination of six soil types and three land uses, referred to as a hydrologic response unit (HRU), was simulated with a separate execution of SWAT. A spatially weighted average was then taken over these results for each hydrologic flux and time step by a separate program, SWBAVG. We wrote a package for MODFLOW to associate each subbasin with a subset of aquifer grid cells and stream reaches, and to distribute the hydrologic fluxes given for each subbasin by SWAT and SWBAVG over MODFLOW's stream-aquifer grid to represent tributary flow, surface and ground water diversions, ground water recharge, and evapotranspiration from ground water. The Lower Republican River Basin model was calibrated with respect to measured ground water levels, streamflow, and reported irrigation water use. The model was used to examine the relative contributions of stream yield components and the impact on stream yield and base flow of administrative measures to restrict irrigation water use during droughts. Model results indicate that tributary flow is the dominant component of stream yield and that reduction of irrigation water use produces a corresponding increase in base flow and stream yield. However, the increase in stream yield resulting from reduced water use does not appear to be of sufficient magnitude to restore minimum desirable streamflows.</p></div></div>","language":"English","publisher":"National Groundwater Association","doi":"10.1111/j.1745-6584.1999.tb01121.x","issn":"0017467X","usgsCitation":"Perkins, S., and Sophocleous, M., 1999, Development of a comprehensive watershed model applied to study stream yield under drought conditions: Groundwater, v. 37, no. 3, p. 418-426, https://doi.org/10.1111/j.1745-6584.1999.tb01121.x.","productDescription":"9 p.","startPage":"418","endPage":"426","numberOfPages":"9","costCenters":[],"links":[{"id":229477,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"37","issue":"3","noUsgsAuthors":false,"publicationDate":"2005-08-04","publicationStatus":"PW","scienceBaseUri":"505a0035e4b0c8380cd4f63d","contributors":{"authors":[{"text":"Perkins, S.P.","contributorId":12211,"corporation":false,"usgs":true,"family":"Perkins","given":"S.P.","email":"","affiliations":[],"preferred":false,"id":390635,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Sophocleous, M.","contributorId":13373,"corporation":false,"usgs":true,"family":"Sophocleous","given":"M.","email":"","affiliations":[],"preferred":false,"id":390636,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}}
,{"id":70021638,"text":"70021638 - 1999 - Sequential filling of a late paleozoic foreland basin","interactions":[],"lastModifiedDate":"2024-05-14T00:06:30.986407","indexId":"70021638","displayToPublicDate":"1999-01-01T00:00:00","publicationYear":"1999","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":2451,"text":"Journal of Sedimentary Research","onlineIssn":"1938-3681","printIssn":"1527-1404","active":true,"publicationSubtype":{"id":10}},"title":"Sequential filling of a late paleozoic foreland basin","docAbstract":"<div><div id=\"12461957\" class=\"article-section-wrapper js-article-section js-content-section  \" data-section-parent-id=\"0\"><p>Through the use of an extensive data base of geophysical well logs, parasequence-scale subdivisions within a late Paleozoic synorogenic clastic wedge resolve cycles of sequential subsidence of a foreland basin, sediment progradation, subsidence of a carbonate shelf edge, diachronously subsiding discrete depositional centers, and basinwide transgression. Although temporal resolution of biostratigraphic markers is less precise in Paleozoic successions than in younger basins, parasequence-scale subdivisions provide more detailed resolution within marker-defined units in Paleozoic strata. As an example, the late Paleozoic Black Warrior basin in the foreland of the Ouachita thrust belt is filled with a synorogenic clastic wedge, the lower part of which intertongues with the fringe of a cratonic carbonate facies in the distal part of the basin. The stratal geometry of one tongue of the carbonate facies (lower tongue of Bangor Limestone) defines a ramp that grades basinward into a thin black shale. An overlying tongue of the synorogenic clastic wedge (lower tongue of Parkwood Formation) consists of cyclic delta and delta-front deposits, in which parasequences are defined by marine-flooding surfaces above coarsening- and shallowing-upward successions of mudstone and sandstone. Within the lower Parkwood tongue, two genetic stratigraphic sequences (A and B) are defined by parasequence offlap and downlap patterns and are bounded at the tops by basinwide maximum-flooding surfaces. The distribution of parasequences within sequences A and B indicates two cycles of sequential subsidence (deepening) and progradation, suggesting subsidence during thrust advance and progradation during thrust quiescence. Parasequence stacking in sequences A and B also indicates diachronous differential tectonic subsidence of two discrete depositional centers within the basin. The uppermost sequence (C) includes reworked sandstones and an overlying shallow-marine limestone, a vertical succession that reflects no tectonic subsidence, a very minor or null sediment supply, and basinwide transgression. The temporal resolution at parasequence scale significantly improves the resolution of the tectonic history of the thrust belt-foreland basin system.</p></div></div>","language":"English","publisher":"Society of Sedimentary Geology","doi":"10.2110/jsr.69.1191","issn":"15271404","usgsCitation":"Mars’, J.C., and Thomas, W., 1999, Sequential filling of a late paleozoic foreland basin: Journal of Sedimentary Research, v. 69, no. 6, p. 1191-1208, https://doi.org/10.2110/jsr.69.1191.","productDescription":"18 p.","startPage":"1191","endPage":"1208","numberOfPages":"18","costCenters":[],"links":[{"id":229108,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"69","issue":"6","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505b8d52e4b08c986b318342","contributors":{"authors":[{"text":"Mars’, J. C.","contributorId":14968,"corporation":false,"usgs":true,"family":"Mars’","given":"J.","email":"","middleInitial":"C.","affiliations":[],"preferred":false,"id":390566,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Thomas, W.A.","contributorId":78104,"corporation":false,"usgs":true,"family":"Thomas","given":"W.A.","email":"","affiliations":[],"preferred":false,"id":390567,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}}
,{"id":70021997,"text":"70021997 - 1999 - Quantification of precipitation measurement discontinuity induced by wind shields on national gauges","interactions":[],"lastModifiedDate":"2018-03-20T14:56:07","indexId":"70021997","displayToPublicDate":"1999-01-01T00:00:00","publicationYear":"1999","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":3722,"text":"Water Resources Research","onlineIssn":"1944-7973","printIssn":"0043-1397","active":true,"publicationSubtype":{"id":10}},"title":"Quantification of precipitation measurement discontinuity induced by wind shields on national gauges","docAbstract":"<p><span>Various combinations of wind shields and national precipitation gauges commonly used in countries of the northern hemisphere have been studied in this paper, using the combined intercomparison data collected at 14 sites during the World Meteorological Organization's (WMO) Solid Precipitation Measurement Intercomparison Project. The results show that wind shields improve gauge catch of precipitation, particularly for snow. Shielded gauges, on average, measure 20–70% more snow than unshielded gauges. Without a doubt, the use of wind shields on precipitation gauges has introduced a significant discontinuity into precipitation records, particularly in cold and windy regions. This discontinuity is not constant and it varies with wind speed, temperature, and precipitation type. Adjustment for this discontinuity is necessary to obtain homogenous precipitation data for climate change and hydrological studies. The relation of the relative catch ratio (RCR, ratio of measurements of shielded gauge to unshielded gauge) versus wind speed and temperature has been developed for Alter and Tretyakov wind shields. Strong linear relations between measurements of shielded gauge and unshielded gauge have also been found for different precipitation types. The linear relation does not fully take into account the varying effect of wind and temperature on gauge catch. Overadjustment by the linear relation may occur at those sites with lower wind speeds, and underadjustment may occur at those stations with higher wind speeds. The RCR technique is anticipated to be more applicable in a wide range of climate conditions. The RCR technique and the linear relation have been tested at selected WMO intercomparison stations, and reasonable agreement between the adjusted amounts and the shielded gauge measurements was obtained at most of the sites. Test application of the developed methodologies to a regional or national network is therefore recommended to further evaluate their applicability in different climate conditions. Significant increase of precipitation is expected due to the adjustment particularly in high latitudes and other cold regions. This will have a meaningful impact on climate variation and change analyses.</span></p>","language":"English","publisher":"American Geophysical Union","doi":"10.1029/1998WR900042","usgsCitation":"Yang, D., Goodison, B.E., Metcalfe, J.R., Louie, P., Leavesley, G.H., Emerson, D.G., Hanson, C.L., Golubev, V.S., Elomaa, E., Gunther, T., Pangburn, T., Kang, E., and Milkovic, J., 1999, Quantification of precipitation measurement discontinuity induced by wind shields on national gauges: Water Resources Research, v. 35, no. 2, p. 491-508, https://doi.org/10.1029/1998WR900042.","productDescription":"18 p.","startPage":"491","endPage":"508","costCenters":[{"id":478,"text":"North Dakota Water Science Center","active":true,"usgs":true},{"id":34685,"text":"Dakota Water Science Center","active":true,"usgs":true}],"links":[{"id":479596,"rank":1,"type":{"id":40,"text":"Open Access Publisher Index Page"},"url":"https://doi.org/10.1029/1998wr900042","text":"Publisher Index Page"},{"id":229160,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"35","issue":"2","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505a91b3e4b0c8380cd803ed","contributors":{"authors":[{"text":"Yang, Daqing","contributorId":203286,"corporation":false,"usgs":false,"family":"Yang","given":"Daqing","email":"","affiliations":[],"preferred":false,"id":391982,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Goodison, Barry E.","contributorId":203293,"corporation":false,"usgs":false,"family":"Goodison","given":"Barry","email":"","middleInitial":"E.","affiliations":[],"preferred":false,"id":391983,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Metcalfe, John R.","contributorId":203294,"corporation":false,"usgs":false,"family":"Metcalfe","given":"John","email":"","middleInitial":"R.","affiliations":[],"preferred":false,"id":391974,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Louie, Paul","contributorId":202388,"corporation":false,"usgs":false,"family":"Louie","given":"Paul","affiliations":[],"preferred":false,"id":391975,"contributorType":{"id":1,"text":"Authors"},"rank":4},{"text":"Leavesley, George H. george@usgs.gov","contributorId":1202,"corporation":false,"usgs":true,"family":"Leavesley","given":"George","email":"george@usgs.gov","middleInitial":"H.","affiliations":[],"preferred":true,"id":391985,"contributorType":{"id":1,"text":"Authors"},"rank":5},{"text":"Emerson, Douglas G.","contributorId":40579,"corporation":false,"usgs":true,"family":"Emerson","given":"Douglas","email":"","middleInitial":"G.","affiliations":[],"preferred":false,"id":391986,"contributorType":{"id":1,"text":"Authors"},"rank":6},{"text":"Hanson, Clayton L.","contributorId":203290,"corporation":false,"usgs":false,"family":"Hanson","given":"Clayton","email":"","middleInitial":"L.","affiliations":[],"preferred":false,"id":391981,"contributorType":{"id":1,"text":"Authors"},"rank":7},{"text":"Golubev, Valentin S.","contributorId":203295,"corporation":false,"usgs":false,"family":"Golubev","given":"Valentin","email":"","middleInitial":"S.","affiliations":[],"preferred":false,"id":391978,"contributorType":{"id":1,"text":"Authors"},"rank":8},{"text":"Elomaa, Esko","contributorId":203296,"corporation":false,"usgs":false,"family":"Elomaa","given":"Esko","email":"","affiliations":[],"preferred":false,"id":391977,"contributorType":{"id":1,"text":"Authors"},"rank":9},{"text":"Gunther, Thilo","contributorId":203287,"corporation":false,"usgs":false,"family":"Gunther","given":"Thilo","email":"","affiliations":[],"preferred":false,"id":391984,"contributorType":{"id":1,"text":"Authors"},"rank":10},{"text":"Pangburn, Timothy","contributorId":203289,"corporation":false,"usgs":false,"family":"Pangburn","given":"Timothy","email":"","affiliations":[],"preferred":false,"id":391979,"contributorType":{"id":1,"text":"Authors"},"rank":11},{"text":"Kang, Ersi","contributorId":195212,"corporation":false,"usgs":false,"family":"Kang","given":"Ersi","email":"","affiliations":[],"preferred":false,"id":391976,"contributorType":{"id":1,"text":"Authors"},"rank":12},{"text":"Milkovic, Janja","contributorId":203292,"corporation":false,"usgs":false,"family":"Milkovic","given":"Janja","email":"","affiliations":[],"preferred":false,"id":391980,"contributorType":{"id":1,"text":"Authors"},"rank":13}]}}
,{"id":70021608,"text":"70021608 - 1999 - The distribution and relative abundance of ammonia-oxidizing bacteria in lakes of the McMurdo Dry Valley, Antarctica","interactions":[],"lastModifiedDate":"2012-03-12T17:19:41","indexId":"70021608","displayToPublicDate":"1999-01-01T00:00:00","publicationYear":"1999","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1919,"text":"Hydrobiologia","onlineIssn":"1573-5117","printIssn":"0018-8158","active":true,"publicationSubtype":{"id":10}},"title":"The distribution and relative abundance of ammonia-oxidizing bacteria in lakes of the McMurdo Dry Valley, Antarctica","docAbstract":"Marked differences in the concentrations of major ions and cations, macronutrient chemistry and general trophic status exist among the lakes of the McMurdo dry valleys in Antarctica. These differences have been attributed to both variations in stream inputs and in situ lake processes (Priscu, 1995; Lizotte et al., 1996, Spigel and Priscu, 1996). This study examines the role of nitrifying bacteria in nitrogen transformations in these lakes. Applying two polymerase chain reaction (PCR) assays targeting the 16S rRNA genes of ammonia-oxidizing bacteria and the active site of the ammonia monooxygenase gene (amoA), the distribution of ammonia-oxidizers was examined in six Antarctic lakes: Lake Bonney, Lake Hoare, Lake Fryxell and Lake Joyce in the Taylor Valley, Lake Miers in the the Miers Valley and Lake Vanda in the Wright Valley. Using a two stage amplification procedure, ammonia-oxidizers from both the beta and gamma- subclasses of the Proteobacteria were detected and their relative abundances were determined in samples collected from all sites. Ammonia-oxidizers were detected in all lakes sampled. Members of the gamma subclass were only present in the saline lakes. In general, nitrifiers were most abundant at depths above the pycnocline and were usually associated with lower concentrations of NH4 and elevated concentrations of NO3 or NO2. The distribution of nitrifiers suggests that the primary N2O peak observed in most of the lakes was produced via nitrification. Preliminary data on the rate of nitrification (Priscu et al., 1996) support the occurrence of nitrification and the presence of nitrifiers at the depth intervals where nitrifiers were detected. In all lakes, except Lake Miers, the data indicate that nitrifying bacteria have an important role in the vertical distribution of nitrogen compounds in these systems.","largerWorkType":{"id":2,"text":"Article"},"largerWorkTitle":"Hydrobiologia","largerWorkSubtype":{"id":10,"text":"Journal Article"},"language":"English","doi":"10.1023/A:1003754830988","issn":"00188158","usgsCitation":"Voytek, M., Priscu, J., and Ward, B., 1999, The distribution and relative abundance of ammonia-oxidizing bacteria in lakes of the McMurdo Dry Valley, Antarctica: Hydrobiologia, v. 401, p. 113-130, https://doi.org/10.1023/A:1003754830988.","startPage":"113","endPage":"130","numberOfPages":"18","costCenters":[],"links":[{"id":229251,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"},{"id":206261,"rank":9999,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.1023/A:1003754830988"}],"volume":"401","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505baacee4b08c986b322a14","contributors":{"authors":[{"text":"Voytek, M.A.","contributorId":44272,"corporation":false,"usgs":true,"family":"Voytek","given":"M.A.","email":"","affiliations":[],"preferred":false,"id":390461,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Priscu, J.C.","contributorId":66396,"corporation":false,"usgs":true,"family":"Priscu","given":"J.C.","email":"","affiliations":[],"preferred":false,"id":390462,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Ward, B.B.","contributorId":7023,"corporation":false,"usgs":true,"family":"Ward","given":"B.B.","email":"","affiliations":[],"preferred":false,"id":390460,"contributorType":{"id":1,"text":"Authors"},"rank":3}]}}
,{"id":70021607,"text":"70021607 - 1999 - Distribution of microbial physiologic types in an aquifer contaminated by crude oil","interactions":[],"lastModifiedDate":"2018-12-14T07:23:46","indexId":"70021607","displayToPublicDate":"1999-01-01T00:00:00","publicationYear":"1999","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":2729,"text":"Microbial Ecology","active":true,"publicationSubtype":{"id":10}},"title":"Distribution of microbial physiologic types in an aquifer contaminated by crude oil","docAbstract":"We conducted a plume-scale study of the microbial ecology in the anaerobic portion of an aquifer contaminated by crude-oil compounds. The data provide insight into the patterns of ecological succession, microbial nutrient demands, and the relative importance of free-living versus attached microbial populations. The most probable number (MPN) method was used to characterize the spatial distribution of six physiologic types: aerobes, denitrifiers, iron-reducers, heterotrophic fermenters, sulfate-reducers, and methanogens. Both free-living and attached numbers were determined over a broad cross-section of the aquifer extending horizontally from the source of the plume at a nonaqueous oil body to 66 m downgradient, and vertically from above the water table to the base of the plume below the water table. Point samples from widely spaced locations were combined with three closely spaced vertical profiles to create a map of physiologic zones for a cross-section of the plume. Although some estimates suggest that less than 1% of the subsurface microbial population can be grown in laboratory cultures, the MPN results presented here provide a comprehensive qualitative picture of the microbial ecology at the plume scale. Areas in the plume that are evolving from iron-reducing to methanogenic conditions are clearly delineated and generally occupy 25-50% of the plume thickness. Lower microbial numbers below the water table compared to the unsaturated zone suggest that nutrient limitations may be important in limiting growth in the saturated zone. Finally, the data indicate that an average of 15% of the total population is suspended.","language":"English","publisher":"Springer","doi":"10.1007/s002489900149","issn":"00953628","usgsCitation":"Bekins, B., Godsy, E., and Warren, E., 1999, Distribution of microbial physiologic types in an aquifer contaminated by crude oil: Microbial Ecology, v. 37, no. 4, p. 263-275, https://doi.org/10.1007/s002489900149.","productDescription":"13 p.","startPage":"263","endPage":"275","costCenters":[{"id":589,"text":"Toxic Substances Hydrology Program","active":true,"usgs":true}],"links":[{"id":229214,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"},{"id":206249,"rank":9999,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.1007/s002489900149"}],"volume":"37","issue":"4","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505a02e2e4b0c8380cd50245","contributors":{"authors":[{"text":"Bekins, B.A.","contributorId":98309,"corporation":false,"usgs":true,"family":"Bekins","given":"B.A.","email":"","affiliations":[],"preferred":false,"id":390459,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Godsy, E.M.","contributorId":56685,"corporation":false,"usgs":true,"family":"Godsy","given":"E.M.","email":"","affiliations":[],"preferred":false,"id":390458,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Warren, E.","contributorId":15360,"corporation":false,"usgs":true,"family":"Warren","given":"E.","email":"","affiliations":[],"preferred":false,"id":390457,"contributorType":{"id":1,"text":"Authors"},"rank":3}]}}
,{"id":70021605,"text":"70021605 - 1999 - Evaluation of stream water quality in Atlanta, Georgia, and the surrounding region (USA)","interactions":[],"lastModifiedDate":"2012-03-12T17:19:41","indexId":"70021605","displayToPublicDate":"1999-01-01T00:00:00","publicationYear":"1999","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1934,"text":"IAHS-AISH Publication","active":true,"publicationSubtype":{"id":10}},"title":"Evaluation of stream water quality in Atlanta, Georgia, and the surrounding region (USA)","docAbstract":"A water-quality index (WQI) was developed from historical data (1986-1995) for streams in the Atlanta Region and augmented with 'new' and generally more comprehensive biweekly data on four small urban streams, representing an industrial area, a developed medium-density residential area and developing and developed low-density residential areas. Parameter WQIs were derived from percentile ranks of individual water-quality parameter values for each site by normalizing the constituent ranks for values from all sites in the area for a base period, i.e. 1990-1995. WQIs were developed primarily for nutrient-related parameters due to data availability. Site WQIs, which were computed by averaging the parameter WQIs, range from 0.2 (good quality) to 0.8 (poor quality), and increased downstream of known nutrient sources. Also, annual site WQI decreases from 1986 to 1995 at most long-term monitoring sites. Annual site WQI for individual parameters correlated with annual hydrological characteristics, particularly runoff, precipitation quantity, and water yield, reflecting the effect of dilution on parameter values. The WQIs of the four small urban streams were evaluated for the core-nutrient-related parameters, parameters for specific dissolved trace metal concentrations and sediment characteristics, and a species diversity index for the macro-invertebrate taxa. The site WQI for the core-nutrient-related parameters used in the retrospective analysis was, as expected, the worst for the industrial area and the best for the low-density residential areas. However, macro-invertebrate data indicate that although the species at the medium-density residential site were diverse, the taxa at the site were for species tolerant of degraded water quality. Furthermore, although a species-diversity index indicates no substantial difference between the two low-density residential areas, the number for macro-invertebrates for the developing area was much less than that for the developed area, consistent with observations of recent sediment problems probably associated with construction in the basin. However, sediment parameters were similar for the two sites suggesting that the routine biweekly measurements may not capture the short-term increases in sediment transport associated with rainstorms. The WQI technique is limited by the number and types of parameters included in it, the general conditions of those parameters for the range of conditions in area streams, and by the effects of external factors, such as hydrology, and therefore, should be used with caution.","largerWorkType":{"id":2,"text":"Article"},"largerWorkTitle":"IAHS-AISH Publication","largerWorkSubtype":{"id":10,"text":"Journal Article"},"conferenceTitle":"Proceedings of the 1999 IUGG 99, the XXII General Assembly of the International Union of Geodesy and Geophysics","conferenceDate":"18 July 1999 through 30 July 1999","conferenceLocation":"Birmingham, UK","language":"English","publisher":"IAHS","publisherLocation":"Houston, TX, United States","issn":"01447815","usgsCitation":"Peters, N., and Kandell, S., 1999, Evaluation of stream water quality in Atlanta, Georgia, and the surrounding region (USA): IAHS-AISH Publication, no. 259, p. 279-290.","startPage":"279","endPage":"290","numberOfPages":"12","costCenters":[],"links":[{"id":229177,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"issue":"259","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505a0cc8e4b0c8380cd52cc8","contributors":{"authors":[{"text":"Peters, N.E.","contributorId":33332,"corporation":false,"usgs":true,"family":"Peters","given":"N.E.","email":"","affiliations":[],"preferred":false,"id":390453,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Kandell, S.J.","contributorId":73067,"corporation":false,"usgs":true,"family":"Kandell","given":"S.J.","affiliations":[],"preferred":false,"id":390454,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}}
,{"id":70021599,"text":"70021599 - 1999 - UCODE, a computer code for universal inverse modeling","interactions":[],"lastModifiedDate":"2012-03-12T17:19:58","indexId":"70021599","displayToPublicDate":"1999-01-01T00:00:00","publicationYear":"1999","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1315,"text":"Computers & Geosciences","printIssn":"0098-3004","active":true,"publicationSubtype":{"id":10}},"title":"UCODE, a computer code for universal inverse modeling","docAbstract":"This article presents the US Geological Survey computer program UCODE, which was developed in collaboration with the US Army Corps of Engineers Waterways Experiment Station and the International Ground Water Modeling Center of the Colorado School of Mines. UCODE performs inverse modeling, posed as a parameter-estimation problem, using nonlinear regression. Any application model or set of models can be used; the only requirement is that they have numerical (ASCII or text only) input and output files and that the numbers in these files have sufficient significant digits. Application models can include preprocessors and postprocessors as well as models related to the processes of interest (physical, chemical and so on), making UCODE extremely powerful for model calibration. Estimated parameters can be defined flexibly with user-specified functions. Observations to be matched in the regression can be any quantity for which a simulated equivalent value can be produced, thus simulated equivalent values are calculated using values that appear in the application model output files and can be manipulated with additive and multiplicative functions, if necessary. Prior, or direct, information on estimated parameters also can be included in the regression. The nonlinear regression problem is solved by minimizing a weighted least-squares objective function with respect to the parameter values using a modified Gauss-Newton method. Sensitivities needed for the method are calculated approximately by forward or central differences and problems and solutions related to this approximation are discussed. Statistics are calculated and printed for use in (1) diagnosing inadequate data or identifying parameters that probably cannot be estimated with the available data, (2) evaluating estimated parameter values, (3) evaluating the model representation of the actual processes and (4) quantifying the uncertainty of model simulated values. UCODE is intended for use on any computer operating system: it consists of algorithms programmed in perl, a freeware language designed for text manipulation and Fortran90, which efficiently performs numerical calculations.","largerWorkType":{"id":2,"text":"Article"},"largerWorkTitle":"Computers and Geosciences","largerWorkSubtype":{"id":10,"text":"Journal Article"},"language":"English","doi":"10.1016/S0098-3004(98)00149-6","issn":"00983004","usgsCitation":"Poeter, E.P., and Hill, M.C., 1999, UCODE, a computer code for universal inverse modeling: Computers & Geosciences, v. 25, no. 4, p. 457-462, https://doi.org/10.1016/S0098-3004(98)00149-6.","startPage":"457","endPage":"462","numberOfPages":"6","costCenters":[],"links":[{"id":229073,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"},{"id":206189,"rank":9999,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.1016/S0098-3004(98)00149-6"}],"volume":"25","issue":"4","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505bbb37e4b08c986b328586","contributors":{"authors":[{"text":"Poeter, E. P.","contributorId":63851,"corporation":false,"usgs":false,"family":"Poeter","given":"E.","email":"","middleInitial":"P.","affiliations":[],"preferred":false,"id":390427,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Hill, M. C.","contributorId":48993,"corporation":false,"usgs":true,"family":"Hill","given":"M.","email":"","middleInitial":"C.","affiliations":[],"preferred":false,"id":390426,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}}
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