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Sample records for anthropogenic lead inputs

  1. A 500 year sediment lake record of anthropogenic and natural inputs to Windermere (English Lake District) using double-spike lead isotopes, radiochronology, and sediment microanalysis.

    PubMed

    Miller, Helen; Croudace, Ian W; Bull, Jonathan M; Cotterill, Carol J; Dix, Justin K; Taylor, Rex N

    2014-07-01

    A high-resolution record of pollution is preserved in recent sediments from Windermere, the largest lake in the English Lake District. Data derived from X-ray core scanning (validated against wavelength dispersive X-ray fluorescence), radiochronological techniques ((210)Pb and (137)Cs) and ultrahigh precision, double-spike mass spectrometry for lead isotopes are combined to decipher the anthropogenic inputs to the lake. The sediment record suggests that while most element concentrations have been stable, there has been a significant increase in lead, zinc, and copper concentrations since the 1930s. Lead isotope down-core variations identify three major contributory sources of anthropogenic (industrial) lead, comprising gasoline lead, coal combustion lead (most likely source is coal-fired steam ships), and lead derived from Carboniferous Pb-Zn mineralization (mining activities). Periods of metal workings do not correlate with peaks in heavy metals due to the trapping efficiency of up-system lakes in the catchment. Heavy metal increases could be due to flood-induced metal inwash after the cessation of mining and the weathering of bedrock in the catchment. The combination of sediment analysis techniques used provides new insights into the pollutant depositional history of Windermere and could be similarly applied to other lake systems to determine the timing and scale of anthropogenic inputs.

  2. Lead isotopic signatures in Antarctic marine sediment cores: a comparison between 1M HCl partial extraction and HF total digestion pre-treatments for discerning anthropogenic inputs.

    PubMed

    Townsend, A T; Snape, I; Palmer, A S; Seen, A J

    2009-12-20

    Sensitive analytical techniques are typically required when dealing with samples from Antarctica as even low concentrations of contaminants can have detrimental environmental effects. Magnetic Sector ICP-MS is an ideal technique for environmental assessment as it offers high sensitivity, multi-element capability and the opportunity to determine isotope ratios. Here we consider the Pb isotope record of five marine sediment cores collected from three sites in the Windmill Islands area of East Antarctica: Brown Bay adjacent to the current Australian station Casey, Wilkes near the abandoned US/Australian Station and McGrady Cove lying midway between the two. Two sediment pre-treatment approaches were considered, namely partial extraction with 1M HCl and total dissolution involving HF. Lead isotope ratio measurements made following sediment partial extraction provided a more sensitive indication of Pb contamination than either Pb concentrations alone (irrespective of sample pre-treatment method) or isotope ratios made after HF digestion, offering greater opportunity for discrimination between impacted and natural/geogenic samples and sites. Over 90% of the easily extractable Pb from sediments near Casey was anthropogenic in origin, consisting of Pb from major Australian deposits. At Wilkes impact from discarded batteries with a unique isotopic signature was found to be a key source of Pb contamination to the marine environment with ~70-80% of Pb being anthropogenic in origin. The country and source of origin of these batteries remain unknown. Little evidence was found suggesting contamination at Wilkes by Pb originating from the major US source, Missouri. No definitive assessment could be made regarding Pb impact at McGrady Cove as the collected sediment core was of insufficient depth. Although Pb isotope ratio signatures may indicate anthropogenic input, spatial concentration gradients at nearby Brown Bay suggest contamination at McGrady Cove is unlikely. We recommend

  3. Tidal salt marsh sediment in California, USA. Part 2: occurrence and anthropogenic input of trace metals.

    PubMed

    Hwang, Hyun-Min; Green, Peter G; Higashi, Richard M; Young, Thomas M

    2006-09-01

    Surface sediment samples (0-5 cm) from 5 tidal salt marshes along the coast in California, USA were analyzed to investigate the occurrence and anthropogenic input of trace metals. Among study areas, Stege Marsh located in the central San Francisco Bay was the most contaminated marsh. Concentrations of metals in Stege Marsh sediments were higher than San Francisco Bay ambient levels. Zinc (55.3-744 microg g(-1)) was the most abundant trace metal and was followed by lead (26.6-273 microg g(-1)). Aluminum normalized enrichment factors revealed that lead was the most anthropogenically impacted metal in all marshes. Enrichment factors of lead in Stege Marsh ranged from 8 to 49 (median=16). Sediments from reference marshes also had high enrichment factors (2-8) for lead, indicating that lead contamination is ubiquitous, possibly due to continuous input from atmospherically transported lead that was previously used as a gasoline additive. Copper, silver, and zinc in Stege Marsh were also enriched by anthropogenic input. Though nickel concentrations in Stege Marsh and reference marshes exceeded sediment quality guidelines, enrichment factors indicated nickel from anthropogenic input was negligible. Presence of nickel-rich source rock such as serpentinite in the San Francisco Bay watershed can explain high levels of nickel in this area. Coefficients of variation were significantly different between anthropogenically impacted and non-impacted metals and might be used as a less conservative indicator for anthropogenic input of metals when enrichment factors are not available.

  4. Industrial age anthropogenic inputs of heavy metals into the pedosphere.

    PubMed

    Han, Fengxiang X; Banin, Amos; Su, Yi; Monts, David L; Plodinec, M John; Kingery, William L; Triplett, Glover E

    2002-11-01

    Heavy metals have been increasingly released into our environment. We present here, for the first time, the global industrial age production of Cd, Cu, Cr, Hg, Ni, Pb, and Zn, and their potential accumulation and environmental effects in the pedosphere. World soils have been seriously polluted by Pb and Cd and slightly by Zn. The potential industrial age anthropogenic Pb, Hg, and Cd inputs in the pedosphere are 9.6, 6.1, and 5.2 times those in the lithosphere, respectively. The potential anthropogenic heavy metal inputs in the pedosphere increased tremendously after the 1950s, especially for Cr and Ni. In 2000, the cumulative industrial age anthropogenic global production of Cd, Cr, Cu, Hg, Ni, Pb, and Zn was 1.1, 105, 451, 0.64, 36, 235, and 354 million tonnes, respectively. The global industrial age metal burdens per capita (in 2000) were 0.18, 17.3, 74.2, 0.10, 5.9, 38.6, and 58.2 kg for Cd, Cr, Cu, Hg, Ni, Pb, and Zn, respectively. Acidification may increase the bioavailability and toxicity of heavy metals in the pedosphere. The improvement of industrial processing technology reducing the metal dispersion rate, the recycling of metal-containing outdated products, by-products and wastes, and the development of new substitute materials for heavy metals are possible strategies to minimize the effects of heavy metals on our environment.

  5. Net Anthropogenic Nitrogen Inputs in the Seattle, WA Metropolitan Area

    NASA Astrophysics Data System (ADS)

    Larson, E. K.; Alberti, M.

    2014-12-01

    Nitrogen loading has been identified as a potential stressor to marine ecosystems of the Puget Sound in the Pacific Northwest, and the Washington State Department of Ecology has estimated that anthropogenic sources of dissolved inorganic nitrogen to the Sound are 2.7 times higher than natural loads (Mohamedali et al. 2011). The Seattle urban area, situated in the southeast of the Sound, has the largest population in the northwestern US. Heavily urbanized along the coast, the 4 counties comprising the region (Snohomish, King, Pierce, and Kitsap) also include forests and agriculture. Urban and agricultural areas tend to have substantial anthropogenic N loading due to fertilizer application, presence of N-fixing vegetation, N atmospheric deposition, and human and other animal waste. To determine the relative contribution of urban vs. rural agricultural activities to N loads from the Seattle region to the Puget Sound, we used the Net Anthropogenic Nitrogen Inputs (NANI) calculator developed by Hong et al. (2011) for the watersheds of this region. The NANI calculator uses nationally available datasets to calculate NANI as the sum of oxidized N deposition, fertilizer application, agricultural N fixation, net food and feed inputs, and net animal and human N consumption. We found that NANI ranged from approximately 100 to 1500 kg m-2 y-1, with some of the highest rates in watersheds with high impervious surface or agricultural areas with N-fixing crops or large fertilizer additions. Many of the agricultural watersheds have intervening low-NANI watershed between themselves and the coast, thus it is likely that agricultural NANI is attenuated before entering the Puget Sound. The urban areas in the region do not have these attenuating watersheds, and so are likely to be the main contributor to the observed total aquatic N yield. This information is helpful for developing policies to reduce N loading to the Sound.

  6. Lead isotopes in the western North Atlantic: Transient tracers of pollutant lead inputs

    SciTech Connect

    Veron, A.J. |; Church, T.M.; Flegal, A.R.

    1998-08-01

    In the early 1980s, Patterson and colleagues demonstrated that most lead in oceanic surface waters had an anthropogenic origin. Their discovery occurred during the phasing out of leaded gasoline in North America initiated in the previous decade. The corresponding decrease in anthropogenic lead emissions, verified by Pb/{sup 210}Pb ratios, accounted for the systematic decline in lead concentrations in surface waters of the western Sargasso Sea. Subsequent changes in anthropogenic lead inputs to the western Sargasso Sea surface waters have been documented by measurements of lead concentrations, isotopic compositions ({sup 206}Pb/{sup 207}Pb, {sup 208}Pb/{sup 206}Pb), and Pb/{sup 210}Pb ratios in precipitation and seawater for the period of 1981 to 1994. These data indicate the easterly trade winds are now the primary source of atmospheric lead in Bermuda, and they confirm that the decline of lead concentrations in the North Atlantic is associated with the phasing out of leaded gasoline in North America and western Europe over the past decade. Moreover, temporal variations in the relative contribution of industrial lead inputs from the two sides of the North Atlantic over that period can be quantified based on differences in their isotopic composition. The transient character of those isotopic signatures also allows calculations of pollutant lead penetration rates into the mixed layer and upper thermocline of the western Sargasso Sea.

  7. Lead isotopes in the western North Atlantic: transient tracers of pollutant lead inputs.

    PubMed

    Véron, A J; Church, T M; Flegal, A R

    1998-08-01

    In the early 1980s, Patterson and colleagues demonstrated that most lead in oceanic surface waters had an anthropogenic origin. Their discovery occurred during the phasing out of leaded gasoline in North America initiated in the previous decade. The corresponding decrease in the anthropogenic lead emissions, verified by Pb/210Pb ratios, accounted for the systematic decline in lead concentrations in surface waters of the western Sargasso Sea. Subsequent changes in anthropogenic lead inputs to the western Sargasso Sea surface waters have been documented by measurements of lead concentrations, isotopic compositions (206Pb/207Pb, 208Pb/206Pb), and Pb/210Pb ratios in precipitation and seawater for the period of 1981 to 1994. These data indicate the easterly trade winds are now the primary source of atmospheric lead in Bermuda, and they confirm that the decline of lead concentrations in the North Atlantic is associated with the phasing out of leaded gasoline in North America and western Europe over the past decade. Moreover, temporal variations in the relative contribution of industrial lead inputs from the two sides of the North Atlantic over that period can be quantified based on differences in their isotopic composition. The transient character of those isotopic signatures also allows calculations of pollutant lead penetration rates into the mixed layer and upper thermocline of the western Sargasso Sea.

  8. A reevaluation of the magnitude and impacts of anthropogenic atmospheric nitrogen inputs on the ocean

    NASA Astrophysics Data System (ADS)

    Jickells, T. D.; Buitenhuis, E.; Altieri, K.; Baker, A. R.; Capone, D.; Duce, R. A.; Dentener, F.; Fennel, K.; Kanakidou, M.; LaRoche, J.; Lee, K.; Liss, P.; Middelburg, J. J.; Moore, J. K.; Okin, G.; Oschlies, A.; Sarin, M.; Seitzinger, S.; Sharples, J.; Singh, A.; Suntharalingam, P.; Uematsu, M.; Zamora, L. M.

    2017-02-01

    We report a new synthesis of best estimates of the inputs of fixed nitrogen to the world ocean via atmospheric deposition and compare this to fluvial inputs and dinitrogen fixation. We evaluate the scale of human perturbation of these fluxes. Fluvial inputs dominate inputs to the continental shelf, and we estimate that about 75% of this fluvial nitrogen escapes from the shelf to the open ocean. Biological dinitrogen fixation is the main external source of nitrogen to the open ocean, i.e., beyond the continental shelf. Atmospheric deposition is the primary mechanism by which land-based nitrogen inputs, and hence human perturbations of the nitrogen cycle, reach the open ocean. We estimate that anthropogenic inputs are currently leading to an increase in overall ocean carbon sequestration of 0.4% (equivalent to an uptake of 0.15 Pg C yr-1 and less than the Duce et al. (2008) estimate). The resulting reduction in climate change forcing from this ocean CO2 uptake is offset to a small extent by an increase in ocean N2O emissions. We identify four important feedbacks in the ocean atmosphere nitrogen system that need to be better quantified to improve our understanding of the perturbation of ocean biogeochemistry by atmospheric nitrogen inputs. These feedbacks are recycling of (1) ammonia and (2) organic nitrogen from the ocean to the atmosphere and back, (3) the suppression of nitrogen fixation by increased nitrogen concentrations in surface waters from atmospheric deposition, and (4) increased loss of nitrogen from the ocean by denitrification due to increased productivity stimulated by atmospheric inputs.

  9. Geochemical features of topsoils in the Gaza Strip: natural occurrence and anthropogenic inputs.

    PubMed

    Shomar, B H; Müller, G; Yahya, A

    2005-07-01

    The aims of this study were to establish the current contents of trace metals and major elements in agricultural soils of the Gaza Strip and to identify the main anthropogenic inputs affecting trace metal contents. An extensive soil survey was conducted in agricultural and nonagricultural areas. One hundred and seventy sites that represent a broad range of soil types and locations were selected. The results revealed that soils in the Gaza Strip fall within the range of uncontaminated to slightly contaminated. Up to 90% of the tested soils had trace metal contents equal to the international background values. Ten percent showed slight contamination, primarily by Zn, Cu, As, and Pb, due to anthropogenic inputs, and the mean concentrations of these elements were 180, 45, 13, and 190 mg/kg, respectively. The trace metal contents varied, with the highest contents detected in the southern regions (where one finds clay soil and low precipitation) and the lowest in the northern areas (where are sandy soil and high precipitation). The soil geochemistry is dependent on soil type and location and to a lesser extent on crop pattern and fertilizer and fungicide application. Anthropogenic inputs lead to the enrichment of Zn, Pb, Cu, and Cd in the agricultural soils. The pollution of several investigated sites was found to be most severe for Zn, Pb, Cu, Cd, and, to a somewhat lesser extent, for As, whereas anthropogenic input of Hg, Ni, and Co seemed to be less important. The application of Cd-containing phosphate fertilizers coupled with Cu-containing fungicides may be an important source of Cd and Cu in several soils. High Zn levels (1000 ppm) in several soils may be caused by sewage sludge, which has an average Zn content of 2000 ppm. Saline-sodic soils were found in the central and southern regions, where the soils are characterized by high contents of Na and salty groundwater. Elevated Cl, Na, Zn, and Pb contents in some areas need further investigation to determine their

  10. Modeling lead input and output in soils using lead isotopic geochemistry.

    PubMed

    Semlali, R M; Dessogne, J B; Monna, F; Bolte, J; Azimi, S; Navarro, N; Denaix, L; Loubet, M; Chateau, C; van Oort, F

    2004-03-01

    The aim of this study is to model downward migration of lead from the plow layer of an experimental site located in Versailles (about 15 km southwest of Paris, France). Since 1928, samples have been collected annually from the topsoil of three control plots maintained in bare fallow. Thirty samples from 10 different years were analyzed for their lead and scandium contents and lead isotopic compositions. The fluxes are simple because of the well-controlled experimental conditions in Versailles: only one output flux, described as a first-order differential function of the anthropogenic lead pool, was taken into account; the inputs were exclusively ascribed to atmospheric deposition. The combination of concentration and isotopic data allows the rate of migration from the plowed topsoil to the underlying horizon and, to a lesser extent, the atmospheric fluxes to be assessed. Both results are in good agreement with the sparse data available. Indeed, the post-depositional migration of lead appears negligible at the human time scale: less than 0.1% of the potentially mobile lead pool migrates downward, out of the first 25 cm of the soil, each year. Assuming future lead inputs equal to 0, at least 700 yr would be required to halve the amount of accumulated lead pollution. Such a low migration rate is compatible with the persistence of a major anthropogenic lead pool deposited before 1928. Knowledge of pollution history seems therefore to be of primary importance.

  11. Invasion of the abyssal North Atlantic by modern anthropogenic lead

    NASA Astrophysics Data System (ADS)

    Alleman, L. Y.; Véron, A. J.; Church, T. M.; Flegal, A. R.; Hamelin, B.

    While anthropogenic emissions have dramatically elevated lead concentrations in the North Atlantic troposphere and surface waters by orders of magnitude above natural levels [Murozumi et al., 1969; Schaule and Patterson, 1983; Boyle et al., 1986], it has been assumed that the relatively low lead levels in North Atlantic abyssal waters are not yet contaminated [Schaule and Patterson, 1981; Flegal and Patterson, 1983]. That misperception is redressed by the following stable lead isotopic composition data which reveal the advective transport of industrial lead into those deep basin waters through the formation of North Atlantic Deep Water (NADW). Additionally, spatial gradients in the isotopic signatures of anthropogenic lead within the North Atlantic abyss appear to serve as transient tracers of contaminant penetration rates.

  12. Inputs of anthropogenic nitrogen influence isotopic composition and trophic structure in SE Australian estuaries.

    PubMed

    Mazumder, Debashish; Saintilan, Neil; Alderson, Brendan; Hollins, Suzanne

    2015-11-15

    Urban development in coastal settings has increased the input of nitrogen into estuaries globally, in many cases changing the composition of estuarine ecosystems. By focussing on three adjacent estuaries with a gradient of anthropogenic N loadings, we used stable isotopes of N and C to test for changes due to increased anthropogenic N input on the structure of some key trophic linkages in estuaries. We found a consistent enrichment in δ(15)N corresponding to increased anthropogenic N at the three ecosystem levels studied: fine benthic organic matter, grazing invertebrate, and planktivorous fish. The degree of enrichment in δ(15)N between fine benthic organic matter and the grapsid crab Parasesarma erythrodactyla was identical across the three sites. The glassfish Ambassis jacksoniensis showed lower levels of enrichment compared to basal food sources at the higher N-loaded sites, suggesting a possible effect of anthropogenic N in decreasing food-chain length in these estuaries. Copyright © 2015 Elsevier Ltd. All rights reserved.

  13. Stable lead isotopes evidence anthropogenic contamination in Alaskan sea otters

    SciTech Connect

    Smith, D.R.; Estes, J.A.; Flegal, A.R. ); Niemeyer, S. )

    1990-10-01

    Lead concentrations and stable isotopic compositions were measured in teeth of preindustrial and contemporary sea otters (Enhydra lutris) from Amchitka Island, AK, to determine if changes had occurred in the magnitude and source of assimilated lead. Although there was no significant difference in lead concentrations between the two groups of otters ({bar x} {plus minus} {sigma}Pb/Ca atomic = 3.6 {plus minus} 2.9 {times} 10{sup {minus}8}), differences in stable lead isotopic compositions revealed a pronounced change in the source of accumulated lead. Lead {bar x} {plus minus} 2{sigma}{sub {bar x}} in the preindustrial otters ({sup 207}Pb/{sup 206}Pb = 0.828 {plus minus} 0.006) was derived from natural deposits in the Aleutian arc, while lead in the contemporary animals ({sup 207}Pb/{sup 206}Pb = 0.856 {plus minus} 0.003) was primarily industrial lead from Asia and western Canada. The isotopic ratios demonstrate anthropogenic perturbations of the lead cycle in present-day coastal food webs and indicate that lead concentration measurements alone are inadequate in assessing the introduction and transport of contaminant lead in the environment.

  14. Impact of anthropogenic induced nitrogen input and liming on phosphorous leaching in forest soils

    NASA Astrophysics Data System (ADS)

    Holzmann, Stefan; Puhlmann, Heike; Wilpert, Klaus

    2016-04-01

    Introduction: Phosphorous (P) is essential for sustainable forest growth, yet the impact of anthropogenic impacts on P leaching losses from forest soils are hardly known. Methods: We conducted an irrigation experiment with 128 mesocosms of 7.4 cm diameter containing 20 cm mineral soil plus the organic layer from three forest sites representing a gradient of resin extractable P of the A-horizon. On each site we selected a Fagus sylvatica and a Picea abies managed subsite. Half of the cylinders where planted with seedlings of the respective species to access the plant impact. We simulated ambient rain (AR), anthropogenic nitrogen input (NI) of 100 kg/ha/a and forest liming (FL) with a dolomite input of 0.3 Mg/ha/a. Soil solution was extracted from the organic layer and at 20 cm depth. We collected the soil solution over a period of 13.5 months and analyzed it separated by 5 periods. The soil solution was analyzed for total phosphorous (TP) by measuring the molybdane reactive phosphorous after acid digestion. To analyze the multivariate dataset we applied random forest modelling and used partial (co-)dependency plots to interpret the results. Results: The TP content of the soil solution from the organic horizon was approximately ten times higher than the soil solution content of the mineral soil. The NI treatment did increase the TP content on all sites. The increase was more pronounced in the organic layer than in the mineral layer. The FL treatment lead to a slight increase of TP in the organic layer while we could observe a slight decrease in the mineral horizon. Both the organic layer and the mineral horizon showed a seasonal cycle with the exception of one Picea abies subsite which displayed a constant increase in TP in the organic layer. The seasonal cycle of the organic horizon had a minimum during the period of April to July, while the minimum at the mineral horizon was during November to January. Conclusion: TP in the soil solution is highest in the organic

  15. Effects of anthropogenic inputs on the organic quality of urbanized streams.

    PubMed

    Kalscheur, Kathryn N; Penskar, Rebecca R; Daley, Allison D; Pechauer, Shannon M; Kelly, John J; Peterson, Christopher G; Gray, Kimberly A

    2012-05-15

    Due to arid conditions, population growth, and anthropogenic impacts from agricultural and urban development, wastewater effluent makes up an increasingly large percentage of surface water supplies promoting concerns about the potential ecological and human health effects associated with the organic quality of surface waters receiving treated wastewater discharge. Anthropogenic inputs alter the quality and quantity of organic carbon and also affect the ability of aquatic ecosystems to retain or transform carbon and other nutrients. In this paper, we use pyrolysis-GC/MS (Py-GC/MS) as a tool to examine whether the dissolved organic carbon (DOC) in suburban streams influenced by anthropogenic inputs displays an organic signature that is structurally different from natural organic material (NOM). Py-GC/MS was not only able to differentiate among stream sites that received discharge from upstream wastewater treatment plants and those that did not, but also distinguished stream sites influenced significantly by storm water. Distinct organic signatures were evident in stream waters with upstream wastewater treatment plant discharges regardless of the distance from effluent discharge, indicative of the persistent nature of effluent-derived organic material (EfOM). The pyrolysis fragments of 3-methyl-pyridine, 2-methyl-pyridine, pyrrole, and acetamide were identified as indicators of EfOM, supporting previous research that has suggested that protein and aminosugar derivitives are possible wastewater markers. Furthermore, pyrolysis fragments associated with soil polycarboxylic acids correlated highly with stream sites having the least anthropogenic influences.

  16. Lead isotopes in sediments of the Loire River (France): natural versus anthropogenic origin

    NASA Astrophysics Data System (ADS)

    Negrel, Ph.; Petelet-Giraud, E.

    2012-04-01

    Sediments along the Loire River (central France) were investigated by means of lead isotopes determined on the labile sediment fraction, or acid-extractable matter (AEM). The combination of trace elements and lead isotopes allows deciphering the origin of the elements (i.e. natural or anthropogenic) and their history, both in the sediment and soil from two small watersheds (one draining basalt, the other one granite-gneiss gneiss in the upper part of the catchment), in present-day suspended matter in Loire River water, and in sediment from the Loire estuary. Fe-Mn oxides act as the main carrier phase of the elements in the AEM extracted by cold HBr, Th and Pb concentrations were determined by ICP-MS and lead isotopes by ICP-MS-MC Neptune. Thorium displays mostly insoluble behaviour in hydrosystems, but the small amount of dissolved Th shows a strong tendency to be adsorbed onto oxyhydroxides. Therefore, Mn and Th (as well as other trace elements) correlate well in AEM, the correlations of Mn, and Pb with Th as a typical indicator of crustal weathering points to their derivation from the silicate basement of the upstream part of the catchment. Crustal weathering, as confirmed by the Pb-isotope ratios for most sample points, is the main natural source of lead in the upstream part of the Loire River, as well as that transported in the middle part of the basin and up to the estuary. Among anthropogenic sources, the use of Pb-isotopic compositions shows an influence of agricultural lead-derived inputs and a large input from lead as a gasoline additive, particularly in the estuary due to harbour activities and for one downstream tributary river that is strongly marked by this type of lead input.

  17. Natural and anthropogenic hydrocarbon inputs to sediments of Patos Lagoon Estuary, Brazil.

    PubMed

    Medeiros, Patricia Matheus; Bícego, Márcia Caruso; Castelao, Renato Menezes; Del Rosso, Clarissa; Fillmann, Gilberto; Zamboni, Ademilson Josemar

    2005-01-01

    The Patos Lagoon Estuary, southern Brazil, is an area of environmental interest not only because of tourism, but also because of the presence of the second major port of Brazil, with the related industrial and shipping activities. Thus, potential hydrocarbon pollution was examined in this study. Sediment samples were collected at 10 sites in the estuary, extracted, and analyzed by GC-FID and GC-MS for composition and concentration of the following organic geochemical markers: normal and isoprenoid alkanes, petroleum biomarkers, linear alkylbenzenes (LABs), and polycyclic aromatic hydrocarbons (PAHs). The total concentrations varied from 1.1 to 129.6 microg g(-1) for aliphatic hydrocarbons, from 17.8 to 4510.6 ng g(-1) for petroleum biomarkers, from 3.2 to 1601.9 ng g(-1) for LABs, and from 37.7 to 11,779.9 ng g(-1) for PAHs. Natural hydrocarbons were mainly derived from planktonic inputs due to a usual development of blooms in the estuary. Terrestrial plant wax compounds prevailed at sites located far from Rio Grande City and subject to stronger currents. Anthropogenic hydrocarbons are related to combustion/pyrolysis processes of fossil fuel, release of unburned oil products and domestic/industrial waste outfalls. Anthropogenic hydrocarbon inputs were more apparent at sites associated with industrial discharges (petroleum distributor and refinery), shipping activities (dry docking), and sewage outfalls (sewage). The overall concentrations of anthropogenic hydrocarbons revealed moderate to high hydrocarbon pollution in the study area.

  18. Anthropogenic Pb input into Bohai Bay, China: Evidence from stable Pb isotopic compositions in sediments

    NASA Astrophysics Data System (ADS)

    Hu, Ningjing; Huang, Peng

    2016-04-01

    Anthropogenic Pb input into Bohai Bay, China: Evidence from stable Pb isotopic compositions in sediments Hu Ning-jinga, Huang Pengb,, Liu Ji-huaa, a First Institute of Oceanography, State Oceanic Administration, Qingdao 266061, China b Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China To investigate the source of Pb within Bohai Bay, Pb concentrations and Pb isotopic compositions (204Pb, 206Pb, 207Pb, and 208Pb) of surface sediments in this area were determined. The Pb concentration in this bay varied widely from 6.9 to 39.2 μg/g (average: 21.8 ± 7.8 μg/g), and the Pb isotopic compositions ranged from 0.8338 to 0.8864 (average: 2.0997 ± 0.0180) for 208Pb/206Pb and from 2.0797 to 2.1531 (average: 0.8477 ± 0.0135) for 207Pb/206Pb, presenting in three distinct clusters. The Pb isotopic ratios of sediments from the northeastern (NE zone) and northwestern (NW zone) coastal areas were significantly influenced by anthropogenic sources such as coal combustion and automobile emission. In sediments from the central and southern Bohai Bay (C-S zone); however, Pb mainly originated from the Yellow River catchment, as a result of lithogenic sediment (from rock weathering) accumulation. The Pb isotopic ratios further indicate that, apart from riverine inputs, the neighboring large-scale ports and aerosols significantly contributed to the anthropogenic Pb contained in these sediments. Pb contamination in the Haihe and Luanhe river mouths as well as in the regions near ports is also suggested from anthropogenic enrichment factors. As cities and ports continue to develop around Bohai Bay, a long-term extensive sewage monitoring program is highly recommended.

  19. Characterization of magnetic particles in the Seine river system : Implications for the determination of natural versus anthropogenic input

    NASA Astrophysics Data System (ADS)

    Franke, C.; Kissel, C.; Robin, E.; Bonté, P.; Lagroix, F.

    2009-04-01

    This study presents an innovative application of well-established environmental magnetic proxy parameters on fluvial sediments with the aim to trace geological and human induced processes in the complex Seine river drainage system in northern France. We determine the regional distribution of the suspended material and search for environmental fingerprints of the influence of fluvial transport mechanisms, changes in the balance of natural input versus anthropogenic pollution and mechanical and chemical weathering processes. To achieve these goals, we apply a combination of straightforward rock magnetic and advanced scanning electron microscopic (SEM) techniques. This interdisciplinary approach allows the analysis of a relatively large number of sediment trap samples with standard methods such as room temperature magnetic hysteresis measurements as well as detailed low-temperature remanence measurements on the bulk sediment material. The absolute quantification of the various components identified in the magnetic assemblage is derived using a SEM automated chemical classification technique. As a general pattern we observe an increase in magnetic concentration coupled with a fining in magnetic grain-size downstream the Seine river system. Additionally we see a general change in the major magneto-mineralogy from high-coercivities in more rural upstream areas to magnetite-dominated assemblages further downstream. Each river (stretch) shows its specific trend line depending on the regional initial input, weathering conditions, drainage area and potential pollution sources. One major highlight of the developed method is the significant correlation (r2=0.9) of anthropogenic antimony containing iron oxide particles with the magnetic concentration. This shows the excellent potential of the magnetic proxy for the recognition of specific heavy metal pollution concentrations. Hence, the applied method serves to identify major trends as well as local particularities and leads to

  20. Declines in Soil pH due to Anthropogenic Nitrogen Inputs Alter Buffering and Exchange Reactions in Tropical Forest Soils

    NASA Astrophysics Data System (ADS)

    Lohse, K. A.

    2003-12-01

    Anthropogenic nitrogen (N) inputs may alter tropical soil buffering and exchange reactions that have important implications for nutrient cycling, forest productivity, and downstream ecosystems. In contrast to relatively young temperate soils that are typically buffered from N inputs by base cation reactions, aluminum reactions may serve to buffer highly weathered tropical soils and result in immediate increases in aluminum mobility and toxicity. Increased nitrate losses due to chronic N inputs may also deplete residual base cations in already weathered base cation-poor soils, further acidify soils, and thereby reduce nitrate mobility through pH-dependent anion exchange reactions. To test these hypotheses, I determined soil pH and cation and anion exchange capacity (CEC and AEC) and measured base cation and aluminum soil solution losses following first-time and long-term experimental N additions from two Hawaiian tropical forest soils, a 300 year old Andisol and a 4.1 million year old Oxisol. I found that elevated base cation losses accompanied increased nitrate losses after first time N additions to the young Andisol whereas immediate and large aluminum losses were associated with increased nitrate losses from the Oxisol. In the long-term, base cation and aluminum losses increased in proportion to nitrate losses. Long-term N additions at both sites resulted in significant declines in soil pH, decreased CEC and increased AEC. These results suggest that even chronic N inputs resulting in small but elevated nitrate losses may deplete residual base cations, increase mobility and toxicity of aluminum, and potentially lead to declines in forest productivity and acidification of downstream ecosystems. These findings also suggest that AEC may provide a long-term mechanism to delay nitrate losses in tropical forests with significant variable charge that are experiencing chronic anthropogenic N inputs.

  1. Net anthropogenic nitrogen inputs and nitrogen fluxes from Indian watersheds: An initial assessment

    NASA Astrophysics Data System (ADS)

    Swaney, D. P.; Hong, B.; Paneer Selvam, A.; Howarth, R. W.; Ramesh, R.; Purvaja, R.

    2015-01-01

    In this paper, we apply an established methodology for estimating Net Anthropogenic Nitrogen Inputs (NANI) to India and its major watersheds. Our primary goal here is to provide initial estimates of major nitrogen inputs of NANI for India, at the country level and for major Indian watersheds, including data sources and parameter estimates, making some assumptions as needed in areas of limited data availability. Despite data limitations, we believe that it is clear that the main anthropogenic N source is agricultural fertilizer, which is being produced and applied at a growing rate, followed by N fixation associated with rice, leguminous crops, and sugar cane. While India appears to be a net exporter of N in food/feed as reported elsewhere (Lassaletta et al., 2013b), the balance of N associated with exports and imports of protein in food and feedstuffs is sensitive to protein content and somewhat uncertain. While correlating watershed N inputs with riverine N fluxes is problematic due in part to limited available riverine data, we have assembled some data for comparative purposes. We also suggest possible improvements in methods for future studies, and the potential for estimating riverine N fluxes to coastal waters.

  2. Dispersal of natural and anthropogenic lead through submarine canyons at the Portuguese margin

    NASA Astrophysics Data System (ADS)

    Richter, T. O.; de Stigter, H. C.; Boer, W.; Jesus, C. C.; van Weering, T. C. E.

    2009-02-01

    Submarine canyons represent natural conduits for preferential transport of particulate material, including anthropogenic contaminants, from coastal zones directly to the deep sea. To assess related dispersal of natural and anthropogenic lead (Pb), we analyzed Pb concentrations and stable isotope ratios in surface sediments and sediment trap particulate material from the Portuguese margin Nazaré and Setúbal/Lisbon canyons. Geochemical data are integrated with previously obtained data on near-bottom hydrodynamics and processes and pathways of sediment transport. The two canyon systems are located in close geographic proximity to each other, but represent contrasting settings in terms of sediment input and down-canyon sediment transport processes. Concentration-isotope diagrams and three-isotope plots ( 206Pb/ 207Pb vs. 208Pb/ 206Pb) suggest binary mixing between natural and anthropogenic end members. The inferred isotopic signature of pollutant Pb ( 206Pb/ 207Pb=1.143 [1.134-1.149, 95% confidence interval]) is most consistent with industrial Pb; ongoing influence from gasoline Pb additives is at most of minor importance. Two proposed natural end members most likely bracket the isotopic signature of natural Pb. Accordingly, binary mixing calculations indicate that on average 20-45% vs. 35-55% of total Pb is derived from anthropogenic sources in the Nazaré and Setúbal-Lisbon canyon systems, respectively. Enhanced anthropogenic influence in the latter area is consistent with its proximity to heavily populated and industrialized areas and with sediment input from the Tagus and Sado rivers, potential major carriers of pollutant particles. In both canyon systems, the anthropogenic component generally decreases with increasing water depth. Isotopic signatures of sediment trap particulate material are generally consistent with surface sediment data at similar water depth, but show large variability in the upper Nazaré canyon and major deviations from surface sediments

  3. Evaluating anthropogenic N inputs to diverse lake basins: A case study of three Chinese lakes.

    PubMed

    Gao, Wei; Swaney, Dennis P; Hong, Bongghi; Howarth, Robert W; Liu, Yong; Guo, Huaicheng

    2015-11-01

    The environmental degradation of lakes in China has become increasingly serious over the last 30 years and eutrophication resulting from enhanced nutrient inputs is considered a top threat. In this study, a quasi-mass balance method, net anthropogenic N inputs (NANI), was introduced to assess the human influence on N input into three typical Chinese lake basins. The resultant NANI exceeded 10,000 kg N km(-2) year(-1) for all three basins, and mineral fertilizers were generally the largest sources. However, rapid urbanization and shrinking agricultural production capability may significantly increase N inputs from food and feed imports. Higher percentages of NANI were observed to be exported at urban river outlets, suggesting the acceleration of NANI transfer to rivers by urbanization. Over the last decade, the N inputs have declined in the basins dominated by the fertilizer use but have increased in the basins dominated by the food and feed import. In the foreseeable future, urban areas may arise as new hotspots for nitrogen in China while fertilizer use may decline in importance in areas of high population density.

  4. Anthropogenic Pb input into Bohai Bay, China: Evidence from stable Pb isotopic compositions in sediments

    NASA Astrophysics Data System (ADS)

    Ning-jing, Hu; Peng, Huang; Hui, Zhang; Ai-mei, Zhu; Ji-hua, Liu; Jun, Zhang; Lian-hua, He

    2015-10-01

    To investigate the source of Pb within Bohai Bay, Pb concentrations and Pb isotopic compositions (204Pb, 206Pb, 207Pb, and 208Pb) of surface sediments in this area were determined. The Pb concentration in this bay varied widely from 6.9 to 39.2 μg/g (average: 21.8±7.8 μg/g), and the Pb isotopic compositions ranged from 0.8338 to 0.8864 (average: 2.0997±0.0180) for 208Pb/206Pb and from 2.0797 to 2.1531 (average: 0.8477±0.0135) for 207Pb/206Pb, presenting in three distinct clusters. The Pb isotopic ratios of sediments from the northeastern (NE zone) and northwestern (NW zone) coastal areas were significantly influenced by anthropogenic sources such as coal combustion and automobile emission. In sediments from the central and southern Bohai Bay (C-S zone); however, Pb mainly originated from the Yellow River catchment, as a result of lithogenic sediment (from rock weathering) accumulation. The Pb isotopic ratios further indicate that, apart from riverine inputs, the neighboring large-scale ports and aerosols significantly contributed to the anthropogenic Pb contained in these sediments. Pb contamination in the Haihe and Luanhe river mouths as well as in the regions near ports is also suggested from anthropogenic enrichment factors. As cities and ports continue to develop around Bohai Bay, a long-term extensive sewage monitoring program is highly recommended.

  5. Increase in stream temperature related to anthropogenic heat input from urban wastewater

    NASA Astrophysics Data System (ADS)

    Kinouchi, T.; Yagi, H.; Miyamoto, M.

    2007-03-01

    SummaryTo better understand long-term temperature changes in urban streams, we investigated stream temperatures in the central Tokyo area and its suburbs from 1978 through 1998. Stream temperature data were analyzed together with data on thermal effluents of urban wastewater and air temperature for the same period. Statistical analyses indicated that the stream temperature in winter and early spring increased at a rate of 0.11-0.21 °C/year in segments that had a considerable increase in wastewater heat input over the same period. These segments showed an appreciable change in the relationship between air temperature and stream temperature, which suggests that the increase in anthropogenic heat input from wastewater was the main cause of the long-term increase in stream temperature. Other possible factors such as increasing air temperature and heat exchange with seawater were found to have comparatively minor influences.

  6. Tracing geogenic and anthropogenic sources in urban dusts: Insights from lead isotopes

    NASA Astrophysics Data System (ADS)

    Del Rio-Salas, R.; Ruiz, J.; De la O-Villanueva, M.; Valencia-Moreno, M.; Moreno-Rodríguez, V.; Gómez-Alvarez, A.; Grijalva, T.; Mendivil, H.; Paz-Moreno, F.; Meza-Figueroa, D.

    2012-12-01

    Tracing the source of metals in the environment is critical to understanding their pollution level and fate. Geologic materials are an important source of airborne particulate matter, but the contribution of contaminated soil to concentrations of Pb in airborne dust is not yet widely documented. To examine the potential significance of this mechanism, surface soil samples were collected, as well as wind-transported dust trapped at 1 and 2 m height at seven different locations including residential, industrial, high-traffic and rural sites. Samples of dust deposited on roofs from 24 schools were also obtained and analyzed for Pb isotope ratios. Spatial distribution of Pb of airborne and sedimented dust suggests a process dominated by re-suspension/sedimentation, which was controlled by erosion, traffic and topography of the urban area. Anthropogenic lead input in the city grades outward the urban zone toward geogenic values. Our results shows that Pb-isotopic signatures of leaded gasoline are imprinted in dust sedimented on roofs. Considering that leaded-gasoline has not been in use in Mexico since two decades ago, this signature shows not only a Pb-legacy in soil, but also a re-suspension process affecting air column below 3 m in height. The combination of the 207Pb/206Pb data of the surrounding rocks and urban dust, reveal three well-defined zones with remarkable anthropogenic influence, which correspond to the oldest urban sectors. This work highlights the importance of spatial characterization of metals in particles suspended below a height of 3 m of the airborne column, a fact that should be considered to identify exposure paths to humans and the potential risks. Lead isotope signatures allowed the identification of geogenic and anthropogenic emission sources for dust, a matter that deserves consideration in the efforts to control airborne metal emissions.

  7. Nutrient dynamics in mangrove crab burrow sediments subjected to anthropogenic input

    NASA Astrophysics Data System (ADS)

    Mchenga, Islam S. S.; Tsuchiya, Makoto

    2008-02-01

    Bioturbation by burrowing macroinvertebrates has a major impact on sediment properties, pollutant redistribution, and biogeochemical cycling. We assessed the impact of bioturbation on the nutrient dynamics and organic matter of sediments receiving anthropogenic inputs in the Manko wetland, located in southern Okinawa, Japan. We compared sediments that were and were not subjected to the activities of the tidal-flat crab Helice formosensis. The fatty acid composition of sediments indicated that different sources contributed to the organic matter profile. Agricultural and domestic waste discharge seemed to induce a high amount of green macroalgae and bacteria in the tidal flat. Sediments without crabs exhibited 2.1-2.4× more NH 4-N release, which was associated with a low C/N ratio during the summer. In the crab burrow sediments, NO 3-N concentrations were 1.4-1.9× more pronounced during winter. A significant correlation existed between NO 3-N and NO 2-N concentrations in sediments of the burrow chamber (r = 0.837, p < 0.02) and the mixed zone of burrow opening shaft and chamber (r = 0.885, p < 0.01). We suggest that burrow wall sediments provide ideal conditions for nitrate reduction (denitrification). H. formosensis thus contributes to balancing the effects of anthropogenic inputs by removing nitrogen loads in sediments.

  8. Effects of anthropogenic nitrogen input on the aquatic food webs of river ecosystem in central Japan

    NASA Astrophysics Data System (ADS)

    Ohte, N.; Togashi, H.; Tokuchi, N.; Yoshimura, M.; Kato, Y.; Ishikawa, N. F.; Osaka, K.; Kondo, M.; Tayasu, I.

    2014-12-01

    To evaluate the impact of the anthropogenic nitrogen input to the river ecosystem, we conducted the monitoring on nutrient status of river waters and food web structures of aquatic organisms. Especially, changes of sources and concentration of nitrate (NO3-) in river water were focused to evaluate the impact of anthropogenic nitrogen loadings from agricultural and residential areas. Stable nitrogen isotope ratio (δ15N) of aquatic organisms has also intensively been monitored not only to describe their food web structure, but also to detect the influences of extraneous nitrogen inputs. Field samplings an observation campaigns were conducted in the Arida river watershed located in central part of Japan at four different seasons from September 2011 to October 2012. Five observation points were set from headwaters to the point just above the brackish waters starts. Water samples for chemical analysis were taken at the observation points for each campaign. Organisms including leaf litters, benthic algae, aquatic insects, crustacean, and fishes were sampled at each point quantitatively. Results of the riverine survey utilizing 5 regular sampling points showed that δ15N of nitrate (NO3-) increased from forested upstream (˜2 ‰) to the downstream (˜7 ‰) due to the sewage loads and fertilizer effluents from agricultural area. Correspondingly the δ15N of benthic algae and aquatic insects increased toward the downstream. This indicates that primary producers of each reach strongly relied on the local N sources and it was utilized effectively in their food web. Simulation using a GIS based mixing model considering the spatial distributions of human population density and fertilizer effluents revealed that strongest impacts of N inputs was originated from organic fertilizers applied to orchards in the middle to lower parts of catchment. Differences in δ15N between primary producers and predators were 6-7 ‰ similarly at all sampling points. Food web structural

  9. The Anthropogenic Effects of Hydrocarbon Inputs to Coastal Seas: Are There Potential Biogeochemical Impacts?

    NASA Astrophysics Data System (ADS)

    Anderson, M. R.; Rivkin, R. B.

    2016-02-01

    Petroleum hydrocarbon discharges related to fossil fuel exploitation have the potential to alter microbial processes in the upper ocean. While the ecotoxicological effects of such inputs are commonly evaluated, the potential for eutrophication from the constituent organic and inorganic nutrients has been largely ignored. Hydrocarbons from natural seeps and anthropogenic sources represent a measurable source of organic carbon for surface waters. The most recent (1989-1997) estimate of average world-wide input of hydrocarbons to the sea is 1.250 x 1012 g/yr ≈ 1.0 x 1012g C/year. Produced water from offshore platforms is the largest waste stream from oil and gas exploitation and contributes significant quantities of inorganic nutrients such as N, P and Fe. In coastal areas where such inputs are a significant source of these nutrients, model studies show the potential to shift production toward smaller cells and net heterotrophy. The consequences of these nutrient sources for coastal systems and semi enclosed seas are complex and difficult to predict, because (1) there is a lack of comprehensive data on inputs and in situ concentrations and (2) the is no conceptual or quantitative framework to consider their effects on ocean biogeochemical processes. Here we use examples from the North Sea (produced water discharges 1% total riverine input and NH4 3% of the annual riverine nitrogen load), the South China Sea (total petroleum hydrocarbons = 10-1750 μg/l in offshore waters), and the Gulf of Mexico (seeps = 76-106 x 109 gC/yr, Macondo blowout 545 x 109 gC) to demonstrate how hydrocarbon and produced water inputs can influence basin scale biogeochemical and ecosystem processes and to propose a framework to consider these effects on larger scales.

  10. Temporal nutrient dynamics in the Mediterranean Sea in response to anthropogenic inputs

    NASA Astrophysics Data System (ADS)

    Moon, Ji-Young; Lee, Kitack; Tanhua, Toste; Kress, Nurit; Kim, Il-Nam

    2016-05-01

    The temporal dynamics of the concentrations of nitrate (N), phosphate (P), and the N:P ratio in the upper water column (200-600 m) of the Mediterranean (MED) Sea were investigated using observational data (~123,100 data points) collected between 1985 and 2014. The studied variables were found to evolve similarly in the western and eastern MED Sea. In both basins, the N concentration increased during the first part of the observational period (1985-1998), and the temporal trend of N was broadly consistent with the history of riverine and atmospheric nitrogen input from populated areas in Europe, with a lag period of 20 years. In subsequent years, the N concentration was high and relatively constant between 1998 and 2005, after which N decreased gradually, although the decreasing trend was indistinct in the western basin. In particular, the trend of constant then declining N after 1998 is consistent with the history of pollutant nitrogen emissions from the European continent, allowing a 20 year lag following the introduction of regulation of pollutant nitrogen in the 1970s. The three-phase temporal transition in P in both basins was more consistent with the riverine phosphorus input, with a lag period of 20 years. Our analysis indicates that the recent dynamics of N and P in the upper MED Sea has been sensitive to the dynamics of anthropogenic nitrogen and phosphorus input from atmospheric deposition and rivers.

  11. Anthropogenic phosphorus (P) inputs to a river basin and their impacts on P fluxes along its upstream-downstream continuum

    NASA Astrophysics Data System (ADS)

    Zhang, Wangshou; Swaney, Dennis; Hong, Bongghi; Howarth, Robert

    2017-04-01

    Phosphorus (P) originating from anthropogenic sources as a pollutant of surface waters has been an environmental issue for decades because of the well-known role of P in eutrophication. Human activities, such as food production and rapid urbanization, have been linked to increased P inputs which are often accompanied by corresponding increases in riverine P export. However, uneven distributions of anthropogenic P inputs along watersheds from the headwaters to downstream reaches can result in significantly different contributions to the riverine P fluxes of a receiving water body. So far, there is still very little scientific understanding of anthropogenic P inputs and their impacts on riverine flux in river reaches along the upstream to downstream continuum. Here, we investigated P budgets in a series of nested watersheds draining into Hongze Lake of China, and developed a simple empirical function to describe the relationship between anthropogenic inputs and riverine TP fluxes. The results indicated that an average of 1.1% of anthropogenic P inputs are exported into rivers, with most of the remainder retained in the watershed landscape over the period studied. Fertilizer application was the main contributor of P loading to the lake (55% of total loads), followed by legacy P stock (30%), food and feed P inputs (12%) and non-food P inputs (4%). From 60% to 89% of the riverine TP loads generated from various locations within this basin were ultimately transported into the receiving lake of the downstream, with an average rate of 1.86 tons P km-1 retaining in the main stem of the inflowing river annually. Our results highlight that in-stream processes can significantly buffer the riverine P loading to the downstream receiving lake. An integrated P management strategy considering the influence of anthropogenic inputs and hydrological interactions is required to assess and optimize P management for protecting fresh waters.

  12. Historical reconstruction of anthropogenic mercury input from sedimentary records: Yeongsan Estuary, South Korea

    NASA Astrophysics Data System (ADS)

    Williams, Joshua; Dellapenna, Timothy; Louchouarn, Patrick; Lee, Guan-hong

    2015-12-01

    The rapid economic growth of the Republic of Korea (S. Korea) within the last half-century has resulted in a pronounced increase in anthropogenic Hg emission from coal combustion, oil refining, cement production, and waste incineration. The record of increasing atmospheric sources have been investigated with a historical reconstruction of Hg accumulation in 30 sediment cores collected from the Yeongsan Estuary. Within the last several decades, this region has undergone severe anthropogenic alteration, including the construction of an estuarine dam forming the Yeongsan Lake, and installation of numerous seawalls that eliminated vast tidal flats and restricted estuarine circulation. Total mercury concentrations (T-Hg) measured in sediments deposited after 1980 (23.2 ± 9.6 ng g-1; n = 273), were significantly higher than those reported for pre-industrial sediments (i.e. background values: 8.6 ± 2.7 ng g-1; n = 274). An extensive survey of surface samples show that T-Hg concentrations are highest above the dam, with a gradient to lower values further offshore. The concomitant timing of enrichment of T-Hg within the sedimentary record and increased National emissions in Korea suggests that regional sources dominate the input to the Yeongsan Estuary. This indicates that with sufficient regional historic emission data, T-Hg might be utilized as a geochronologic tool to aid in corroborating traditional radioisotopic methods.

  13. Freshwater mussels in an urban watershed: Impacts of anthropogenic inputs and habitat alterations on populations.

    PubMed

    Gillis, Patricia L; McInnis, Rodney; Salerno, Joseph; de Solla, Shane R; Servos, Mark R; Leonard, Erin M

    2017-01-01

    The substantial increase in urbanization worldwide has resulted in higher emissions of wastewater to riverine systems near urban centers, which often impairs aquatic populations and communities. This study examined the effect of urbanization on freshwater mussel populations, including Species at Risk in two rivers receiving wastewater. The influence of anthropogenic activities was assessed in a watershed in the Laurentian Great Lakes basin, one that historically supported one of the most diverse mussel faunas in Canada. In the Grand River (ON), four sites along a 60km reach spanning from an upstream reference site to an urban-impacted downstream area were examined. In the Speed River, mussel populations at six sites along a 10km reach, selected to bracket specific anthropogenic inputs and structures were assessed. A semi-quantitative visual search method revealed that catch per unit effort in the Grand River declined by >60% from the upstream reference site to the area downstream of an urban center. The size (length) frequency distribution of the most abundant species, Lasmigona costata, was significantly (p≤0.008) different upstream of the majority of urban inputs (45-130mm) compared to downstream of the cities (85-115mm). In the Speed River, impoundments and wastewater treatment plants (WWTP) reduced both the diversity and catch per effort. Most striking were 84 and 95% changes in the number of mussels found on either side of two impoundments, and a 98% drop in mussels immediately downstream of a WWTP outfall. These population level effects of decreased abundance and underrepresentation of smaller mussels downstream of the urban area correspond to previously documented impacts at the biochemical and whole organism level of biological organization in wild mussels at this location. Our results demonstrate that poor water quality and physical barriers in urban environments continue to impair susceptible populations and communities of aquatic animals. Crown

  14. Anthropogenic activities have contributed moderately to increased inputs of organic materials in marginal seas off China.

    PubMed

    Liu, Liang-Ying; Wei, Gao-Ling; Wang, Ji-Zhong; Guan, Yu-Feng; Wong, Charles S; Wu, Feng-Chang; Zeng, Eddy Y

    2013-10-15

    Sediment has been recognized as a gigantic sink of organic materials and therefore can record temporal input trends. To examine the impact of anthropogenic activities on the marginal seas off China, sediment cores were collected from the Yellow Sea, the inner shelf of the East China Sea (ECS), and the South China Sea (SCS) to investigate the sources and spatial and temporal variations of organic materials, i.e., total organic carbon (TOC) and aliphatic hydrocarbons. The concentration ranges of TOC were 0.5-1.29, 0.63-0.83, and 0.33-0.85%, while those of Σn-C14-35 (sum of n-alkanes with carbon numbers of 14-35) were 0.08-1.5, 0.13-1.97, and 0.35-0.96 μg/g dry weight in sediment cores from the Yellow Sea, ECS inner shelf, and the SCS, respectively. Terrestrial higher plants were an important source of aliphatic hydrocarbons in marine sediments off China. The spatial distribution of Σn-C14-35 concentrations and source diagnostic ratios suggested a greater load of terrestrial organic materials in the Yellow Sea than in the ECS and SCS. Temporally, TOC and Σn-C14-35 concentrations increased with time and peaked at either the surface or immediate subsurface layers. This increase was probably reflective of elevated inputs of organic materials to marginal seas off China in recent years, and attributed partly to the impacts of intensified anthropogenic activities in mainland China. Source diagnostics also suggested that aliphatic hydrocarbons were mainly derived from biogenic sources, with a minority in surface sediment layers from petroleum sources, consistent with the above-mentioned postulation.

  15. Sources and Evolution of Anthropogenic Lead in Northwestern Pacific Seawater: High Resolution Coral Pb Isotope Record

    NASA Astrophysics Data System (ADS)

    Wang, B.; You, C.; Nohda, S.

    2008-12-01

    Lattice-bound Lead in scleractinian coral skeletons provides a potential tracer to investigate the historical anthropogenic disturbance in the surface ocean. In this study, a Porites coral core collected from an islet offshore southeastern Taiwan was used to reconstruct decadal lead variation in surface seawater at northwestern Pacific. Seasonal Pb/Ca peaks are in accordance with rainfall episodes, while the long-term trend shows high lead input before 1970s. This can be attributed to extensively use of alkyl-lead in the region. Moreover, temporal variations of lead isotope display a significant change of lead sources in mid-20 th, coinciding with the Australian Pb imported period. These isotopic signatures also indicate contribution from China/Japan pollutant through atmospheric circulation during 1962-1998. This preliminary study infers that Pb in surface seawater is dominantly transported by ocean current and aeolian deposition from adjacent urban area, while Pb concentration may not reflect entirely the source flux due to potential loss during transportation.

  16. Natural and anthropogenic trace-metal input into the coastal and estuarine sediments of the straits of Malacca

    SciTech Connect

    Din, Z.B.

    1995-11-01

    One of the concerns of local management authority in Malaysia is the problem of metal pollution in the coastal waters. Approximately 44% of toxic and hazardous wastes in Peninsular Malaysia was contributed by the metal finishing industries. However, available data and publications are very limited and patchy. Most of the studies that have been conducted were on metal contents in fish and shellfish with less than a handful on metal contents in the environment. With regard to metal contents in the coastal sediments around Malaysia, all the values that have been documented are total concentration of individual metal. Although this kind of information is useful, it has its limitation, and in some cases it may lead to erroneous conclusions. This is because particulate metals from natural and anthropogenic sources accumulate together in the sediment. In order to determine the level of metal pollution in an area we do need to isolate the two metal proportions and this can pose problems because sedimentary metal load can vary by several orders of magnitude, depending on the mineralogy and grain-size distribution of the area. Thus, in order to properly interpret the status of metal pollution in an area, a normalization procedure is recommended so that we will be able to compensate for natural variability of the metals in the sediment, which would then enable us to detect and quantify any anthropogenic metal contribution to the system. In this study, natural and anthropogenic trace metal input into the Straits of Malacca was estimated based on normalization procedures using aluminum as the reference material since it was shown to work for several metals in the area. 14 refs., 2 figs., 2 tabs.

  17. Tracing the transport of anthropogenic lead in the atmosphere and in soils using isotopic ratios

    NASA Astrophysics Data System (ADS)

    Erel, Yigal; Veron, Alain; Halicz, Ludwik

    1997-11-01

    The isotopic composition of lead in aerosols and soils in Israel is used to characterize the sources of anthropogenic lead in the region, to ascertain the isotopic composition of natural, rock-derived lead in specific areas, and to determine rates of anthropogenic lead migration in soils. The isotopic composition of lead currently emitted from cars in Israel ( 206Pb /207Pb = 1.115 ± 2 ) is controlled by alkyl-lead produced in France and Germany. In addition to petrol-lead, two more sources of anthropogenic lead can be detected in sampled aerosols: the first one has low concentrations of lead (˜4 ng/m 3) and 206Pb /207Pb ˜ 1.157 , and is most likely lead, emitted in Turkey, that traveled across the eastern Mediterranean basin; the second type of aerosols contains a mixture of lead emitted in several countries including Turkey, Greece, and Ukraine ( 206Pb /207Pb value of 1.155-1.160; [Pb] ˜ 20-30 ng/m 3). Anthropogenic lead is more accessible for acid leaching than natural lead, therefore, it is more labile in the soil. The isotopic composition of lead in the acid-leached fraction of near-road soil profiles record the histor of alkyl-lead emission in the country. Based on changes in the isotopic composition of lead with soil depth, it is estimated that anthropogenic lead migrates into the soil at approximately 0.5 cm/y. A soil profile from a relatively remote area is less contaminated by anthropogenic lead and displays a different distribution of lead isotopic values with depth. The isotopic composition of lead suggests that natural lead in soils developed on carbonate bedrock is derived from clays, either from the rock-esidue (the clay fraction in the carbonate bedrock), or from airborne clay, but not from lead released from the carbonate fraction in the rock.

  18. Estimated anthropogenic nitrogen and phosphorus inputs to the land surface of the conterminous United States--1992, 1997, and 2002

    USGS Publications Warehouse

    Sprague, Lori A.; Gronberg, Jo Ann M.

    2013-01-01

    Anthropogenic inputs of nitrogen and phosphorus to each county in the conterminous United States and to the watersheds of 495 surface-water sites studied as part of the U.S. Geological Survey National Water-Quality Assessment Program were quantified for the years 1992, 1997, and 2002. Estimates of inputs of nitrogen and phosphorus from biological fixation by crops (for nitrogen only), human consumption, crop production for human consumption, animal production for human consumption, animal consumption, and crop production for animal consumption for each county are provided in a tabular dataset. These county-level estimates were allocated to the watersheds of the surface-water sites to estimate watershed-level inputs from the same sources; these estimates also are provided in a tabular dataset, together with calculated estimates of net import of food and net import of feed and previously published estimates of inputs from atmospheric deposition, fertilizer, and recoverable manure. The previously published inputs are provided for each watershed so that final estimates of total anthropogenic nutrient inputs could be calculated. Estimates of total anthropogenic inputs are presented together with previously published estimates of riverine loads of total nitrogen and total phosphorus for reference.

  19. Estimating net anthropogenic nitrogen inputs (NANI) in the Lake Dianchi basin of China

    NASA Astrophysics Data System (ADS)

    Gao, W.; Howarth, R. W.; Hong, B.; Swaney, D. P.; Guo, H. C.

    2014-08-01

    Net anthropogenic nitrogen inputs (NANI) with components of atmospheric N deposition, synthetic N fertilizer, agricultural N fixation and N in net food and feed imports from 15 catchments in the Lake Dianchi basin were determined over an 11-year period (2000-2010). The 15 catchments range in size from 44 km2 to 316 km2 with an average of 175 km2. To reduce uncertainty from scale change methodology, results from data extraction by area-weighting and land use-weighting methods were compared. Results show that the methodology for extrapolating data from the county scale to watersheds has a great influence on NANI computation for catchments in the Lake Dianchi basin, and that estimates of NANI between the two methods have an average difference of 30% on a catchment basis, while a smaller difference (15%) was observed on the whole Lake Dianchi basin basis. The riverine N export has a stronger linear relationship with NANI computed by the land use-weighting method, which we believe is more reliable. Overall, nitrogen inputs assessed by the NANI approach for the Lake Dianchi basin are 9900 kg N km-2 yr-1, ranging from 6600 to 28 000 kg N km-2 yr-1 among the 15 catchments. Synthetic N fertilizer is the largest component of NANI in most subwatersheds. On average, riverine flux of nitrogen in catchments of the Lake Dianchi basin averages 83% of NANI, far higher than generally observed in North America and Europe. Saturated N sinks and a limited capacity for denitrification in rivers may be responsible for this high percentage of riverine N export. Overall, the NANI methodology should be applicable in small watersheds when sufficiently detailed data are available to estimate its components.

  20. Estimating net anthropogenic nitrogen inputs (NANI) in the Lake Dianchi Basin of China

    NASA Astrophysics Data System (ADS)

    Gao, W.; Howarth, R. W.; Hong, B.; Swaney, D. P.; Guo, H. C.

    2014-03-01

    Net anthropogenic nitrogen inputs (NANI) with components of atmospheric N deposition, synthetic N fertilizer, agricultural N fixation and N in net food and feed imports from 15 catchments in Lake Dianchi Basin were determined over an 11 year period (2000-2010). The 15 catchments range in size from 44 km2 to 316 km2 with an average of 175 km2. To reduce uncertainty from scale change methodology, results from data extracting by area-weighting and land use-weighting methods were compared. Results show that methodology for extrapolating data from county scale to watersheds has a great influence on NANI computation for catchments in the Lake Dianchi Basin, and estimates of NANI between two methods have an average difference of 30% on catchments basis while a smaller difference (15%) was observed on the whole Lake Dianchi Basin basis. The riverine N export has stronger linear relationship with NANI computed by land use-weighting method, which we believe is more reliable. Overall, nitrogen inputs assessed by the NANI approach for the Lake Dianchi Basin are 9900 kg N km-2 yr-1, ranging from 6600 to 28 000 kg N km-2 yr-1 among the 15 catchments. Synthetic N fertilizer is the largest component of NANI in most subwatersheds. On average, riverine flux of nitrogen in catchments of the Lake Dianchi Basin averages 83% of NANI, far higher than generally observed in North America and Europe. Saturated N sinks and limited capacity for denitrification in rivers may be responsible for this high percent of riverine N export. A negative intercept observed in the linear relationship between NANI and riverine N export suggests the influence of pollution control measures on N flux in small watershed. The NANI methodology should be applicable in small watersheds when sufficiently detailed data are available to estimate its components.

  1. Utilization of a submersible UV fluorometer for monitoring anthropogenic inputs in the Mediterranean coastal waters.

    PubMed

    Tedetti, Marc; Guigue, Catherine; Goutx, Madeleine

    2010-03-01

    We evaluated the performances of a submersible ultraviolet fluorometer (EnviroFlu-HC, TriOS Optical Sensors) dedicated to the real time measurement of polycyclic aromatic hydrocarbons (PAHs) in the aquatic media. We conducted calibration experiments and in situ measurements in the coastal Mediterranean Sea. We found that the EnviroFlu-HC was not strictly specific to PAHs, even though it exhibited the highest sensitivity for phenanthrene, but could response to tryptophan-like material as well, and in a much less extent, to humic substances. The sensor signal showed great spatial and temporal variations in clean and polluted sites, with likely a high contribution of PAHs in the harbors, and a high contribution of tryptophan-like and humic-like materials in the sewage effluent. We conclude that the EnviroFlu-HC is a good tool for monitoring anthropogenic inputs in the coastal waters, although its utilization should be combined to other fluorescence measurements to improve the information about the nature of the aromatic compounds detected. Copyright 2009 Elsevier Ltd. All rights reserved.

  2. Tracking anthropogenic inputs using caffeine, indicator bacteria, and nutrients in rural freshwater and urban marine systems.

    PubMed

    Peeler, Kelly A; Opsahl, Stephen P; Chanton, Jeffrey P

    2006-12-15

    Our objective was to evaluate the hypothesis that measurements of caffeine, nutrients, and indicator bacteria can distinguish human versus non-human sources of surface water contamination in contrasting environments. A second objective was to determine if natural sources of caffeine were significant in unpopulated areas. Caffeine was measured in an isolated wetland, and a native plant source was identified. In two rural watersheds in southwest Georgia (U.S.), caffeine was detected in tributary creeks immediately below wastewater discharge sites and within towns. However, caffeine was not found in river main streams. Thus, although natural caffeine sources exist, background levels in stream drainage networks of these rural watersheds remained below detection. The presence of caffeine and elevated nitrate in streams was associated with anthropogenic inputs and population centers, whereas bacterial indicators did not correlate to these chemical indicators and appeared to have non-human sources. In contrast, caffeine in an urban coastal lagoon was generally linked to fecal coliform abundance. We observed sporadic relationships between caffeine and other water quality indicators, possibly due to differential rates of degradation. Creeks and bayous flowing into the lagoon contained the greatest caffeine concentrations and highest amounts of bacteria, nitrate, and radon, which is an indicator of groundwater discharge.

  3. Macroalgae δ15N values in well-mixed estuaries: Indicator of anthropogenic nitrogen input or macroalgae metabolism?

    NASA Astrophysics Data System (ADS)

    Raimonet, Mélanie; Guillou, Gaël; Mornet, Françoise; Richard, Pierre

    2013-03-01

    Although nitrogen stable isotope ratio (δ15N) in macroalgae is widely used as a bioindicator of anthropogenic nitrogen inputs to the coastal zone, recent studies suggest the possible role of macroalgae metabolism in δ15N variability. Simultaneous determinations of δ15N of dissolved inorganic nitrogen (DIN) along the land-sea continuum, inter-species variability of δ15N and its sensitivity to environmental factors are necessary to confirm the efficiency of macroalgae δ15N in monitoring nitrogen origin in mixed-use watersheds. In this study, δ15N of annual and perennial macroalgae (Ulva sp., Enteromorpha sp., Fucus vesiculosus and Fucus serratus) are compared to δ15N-DIN along the Charente Estuary, after characterizing δ15N of the three main DIN sources (i.e. cultivated area, pasture, sewage treatment plant outlet). During late winter and spring, when human activities produce high DIN inputs, DIN sources exhibit distinct δ15N signals in nitrate (NO) and ammonium (NH): cultivated area (+6.5 ± 0.6‰ and +9.0 ± 11.0‰), pasture (+9.2 ± 1.8‰ and +12.4‰) and sewage treatment plant discharge (+16.9 ± 8.7‰ and +25.4 ± 5.9‰). While sources show distinct δN- in this multiple source catchment, the overall mixture of NO sources - generally >95% DIN - leads to low variations of δN-NO at the mouth of the estuary (+7.7 to +8.4‰). Even if estuarine δN-NO values are not significantly different from pristine continental and oceanic site (+7.3‰ and +7.4‰), macroalgae δ15N values are generally higher at the mouth of the estuary. This highlights high anthropogenic DIN inputs in the estuary, and enhanced contribution of 15N-depleted NH in oceanic waters. Although seasonal variations in δN-NO are low, the same temporal trends in macroalgae δ15N values at estuarine and oceanic sites, and inter-species differences in δ15N values, suggest that macroalgae δ15N values might be modified by the metabolic response of macroalgae to environmental parameters (e

  4. Contrasting behaviour of anthropogenic gadolinium and natural rare earth elements in estuaries and the gadolinium input into the North Sea

    NASA Astrophysics Data System (ADS)

    Kulaksız, Serkan; Bau, Michael

    2007-08-01

    All major rivers in northwestern Germany that flow into the North Sea, including the Weser River, display rare earth element (REE) patterns with large positive gadolinium (Gd) anomalies that indicate the presence of anthropogenic Gd derived from contrast agents used in magnetic resonance imaging. This microcontaminant cannot be removed by common sewage treatment technology and enters rivers and lakes with the discharge from waste water treatment plants. As elsewhere, a large fraction of the natural dissolved REE in the Weser River are associated with colloids. These colloids aggregate during mixing of freshwater and seawater in the low-salinity part of the Weser Estuary and the dissolved REE are partially removed from the river water together with the colloids. In marked contrast to the natural REE, the anthropogenic Gd behaves conservatively during this estuarine mixing and transits through the Weser Estuary almost unaffected. This indicates that the speciation of anthropogenic Gd is different from that of natural Gd and suggests a long environmental half-life of the anthropogenic Gd complexes used as contrast agents. The amount of anthropogenic Gd introduced into seawater via rivers is significant and produces anthropogenic positive Gd anomalies in coastal seawater. This is observed in the southwestern North Sea, off the coast of the East Frisian Islands, where anthropogenic Gd is mostly derived from the rivers Rhine and Thames. Its long environmental half-life and conservative estuarine behaviour suggest that anthropogenic Gd might be utilized as a pseudo-natural far-field tracer for truly dissolved riverine REE input into seawater and for discharge from waste water treatment plants and for sewage in river, ground and drinking water. The widespread distribution of anthropogenic Gd is an example of how the increasing use of "exotic" (ultra)trace elements in high-tech processes will in the future significantly hamper studies of the distribution and geochemical

  5. Tracing the transport of anthropogenic lead in the atmosphere and in soils using isotopic ratios

    SciTech Connect

    Erel, Y.; Veron, A.; Halicz, L.

    1997-11-01

    The isotopic composition of lead in aerosols and soils in Israel is used to characterize the sources of anthropogenic lead in the region, to ascertain the isotopic composition of natural, rock-derived lead in specific areas, and to determine rates of anthropogenic lead migration in soils. The isotopic composition of lead currently emitted from cars in Israel ({sup 206}Pb/{sup 207}Pb = 1.115 {+-} 2) is controlled by alkyl-lead produced in France and Germany. In addition to petrol-lead, two more sources of anthropogenic lead can be detected in sampled aerosols; the first one has low concentrations of lead ({approximately} ng/m{sup 3}) and {sup 206}Pb/{sup 207}Pb {approximately} 1.157, and is most likely lead, emitted in Turkey, that traveled across the eastern Mediterranean basin; the second type of aerosols contains a mixture of lead emitted in several countries including Turkey, Greece, and Ukraine ({sup 206}Pb/{sup 207}Pb value of 1.155-1.160; [Pb] {approximately}20-30 ng/m{sup 3}). Anthropogenic lead is more accessible for acid leaching than natural lead, therefore, it is more labile in the soil. The isotopic composition of lead in the acid-leached fraction of near-road soil profiles records the history of alkyl-lead emission in the country. Based on changes in the isotopic composition of lead with soil depth, it is estimated that anthropogenic lead migrates into the soil at approximately 0.5 cm/y. A soil profile from a relatively remote area is less contaminated by anthropogenic lead and displays a different distribution of lead isotopic values with depth. The isotopic composition of lead suggests that natural lead in soils developed on carbonate bedrock is derived from clays, either from the rock-residue (the clay fraction in the carbonate bedrock), or from airborne clay, but not from lead released from the carbonate fraction in the rock. 44 refs., 6 figs., 2 tabs.

  6. How inhibiting nitrification affects nitrogen cycle and reduces environmental impacts of anthropogenic nitrogen input.

    PubMed

    Qiao, Chunlian; Liu, Lingli; Hu, Shuijin; Compton, Jana E; Greaver, Tara L; Li, Quanlin

    2015-03-01

    Anthropogenic activities, and in particular the use of synthetic nitrogen (N) fertilizer, have doubled global annual reactive N inputs in the past 50-100 years, causing deleterious effects on the environment through increased N leaching and nitrous oxide (N2 O) and ammonia (NH3 ) emissions. Leaching and gaseous losses of N are greatly controlled by the net rate of microbial nitrification. Extensive experiments have been conducted to develop ways to inhibit this process through use of nitrification inhibitors (NI) in combination with fertilizers. Yet, no study has comprehensively assessed how inhibiting nitrification affects both hydrologic and gaseous losses of N and plant nitrogen use efficiency. We synthesized the results of 62 NI field studies and evaluated how NI application altered N cycle and ecosystem services in N-enriched systems. Our results showed that inhibiting nitrification by NI application increased NH3 emission (mean: 20%, 95% confidential interval: 33-67%), but reduced dissolved inorganic N leaching (-48%, -56% to -38%), N2 O emission (-44%, -48% to -39%) and NO emission (-24%, -38% to -8%). This amounted to a net reduction of 16.5% in the total N release to the environment. Inhibiting nitrification also increased plant N recovery (58%, 34-93%) and productivity of grain (9%, 6-13%), straw (15%, 12-18%), vegetable (5%, 0-10%) and pasture hay (14%, 8-20%). The cost and benefit analysis showed that the economic benefit of reducing N's environmental impacts offsets the cost of NI application. Applying NI along with N fertilizer could bring additional revenues of $163 ha(-1)  yr(-1) for a maize farm, equivalent to 8.95% increase in revenues. Our findings showed that NIs could create a win-win scenario that reduces the negative impact of N leaching and greenhouse gas production, while increases the agricultural output. However, NI's potential negative impacts, such as increase in NH3 emission and the risk of NI contamination, should be fully

  7. Modeling and forecasting riverine dissolved inorganic nitrogen export using anthropogenic nitrogen inputs, hydroclimate, and land-use change

    NASA Astrophysics Data System (ADS)

    Huang, Hong; Chen, Dingjiang; Zhang, Baifa; Zeng, Lingzao; Dahlgren, Randy A.

    2014-09-01

    A quantitative understanding of riverine nitrogen (N) export in response to human activities and climate change is critical for developing effective watershed N pollution control measures. This study quantified net anthropogenic N inputs (NANI) and riverine dissolved inorganic N (DIN = NO3-N + NH4-N + NO2-N) export for the upper Jiaojiang River catchment in eastern China over the 1980-2010 time period and examined how NANI, hydroclimate, and land-use practices influenced riverine DIN export. Over the 31-yr study period, riverine DIN yield increased by 1.6-fold, which mainly results from a ∼77% increase in NANI and increasing fractional delivery of NANI due to a ∼55% increase in developed land area. An empirical model that utilizes an exponential function of NANI and a power function of combining annual water discharge and developed land area percentage could account for 89% of the variation in annual riverine DIN yields in 1980-2010. Applying this model, annual NANI, catchment storage, and natural background sources were estimated to contribute 57%, 22%, and 21%, respectively, of annual riverine DIN exports on average. Forecasting based on a likely future climate change scenario predicted a 19.6% increase in riverine DIN yield by 2030 due to a 4% increase in annual discharge with no changes in NANI and land-use compared to the 2000-2010 baseline condition. Anthropogenic activities have increased both the N inputs available for export and the fractional export of N inputs, while climate change can further enhance riverine N export. An integrated N management strategy that considers the influence of anthropogenic N inputs, land-use and climate change is required to effectively control N inputs to coastal areas.

  8. MNA As A Remedy For Arsenic Mobilized By Anthropogenic Inputs Of Organic Carbon

    EPA Science Inventory

    The potential application of monitored natural attenuation (MNA) as a remedy for ground water contaminated with arsenic (As) is examined for a subset of contaminated sites, specifically those where naturally occurring As has been mobilized due to localized anthropogenic organic c...

  9. Seasonal variations in the sources of natural and anthropogenic lead deposited at the East Rongbuk Glacier in the high-altitude Himalayas.

    PubMed

    Burn-Nunes, Laurie; Vallelonga, Paul; Lee, Khanghyun; Hong, Sungmin; Burton, Graeme; Hou, Shugui; Moy, Andrew; Edwards, Ross; Loss, Robert; Rosman, Kevin

    2014-07-15

    Lead (Pb) isotopic compositions and concentrations, and barium (Ba) and indium (In) concentrations have been analysed at sub-annual resolution in three sections from a <110 m ice core dated to the 18th and 20th centuries, as well as snow pit samples dated to 2004/2005, recovered from the East Rongbuk Glacier in the high-altitude Himalayas. Ice core sections indicate that atmospheric chemistry prior to ~1,953 was controlled by mineral dust inputs, with no discernible volcanic or anthropogenic contributions. Eighteenth century monsoon ice core chemistry is indicative of dominant contributions from local Himalayan sources; non-monsoon ice core chemistry is linked to contributions from local (Himalayan), regional (Indian/Thar Desert) and long-range (North Africa, Central Asia) sources. Twentieth century monsoon and non-monsoon ice core data demonstrate similar seasonal sources of mineral dust, however with a transition to less-radiogenic isotopic signatures that suggests local and regional climate/environmental change. The snow pit record demonstrates natural and anthropogenic contributions during both seasons, with increased anthropogenic influence during non-monsoon times. Monsoon anthropogenic inputs are most likely sourced to South/South-East Asia and/or India, whereas non-monsoon anthropogenic inputs are most likely sourced to India and Central Asia. Copyright © 2014 Elsevier B.V. All rights reserved.

  10. Anthropogenic Lead Deposition over the last 15,000 years in Northern New Mexico

    NASA Astrophysics Data System (ADS)

    Cisneros-Dozal, L.; Fessenden, J.; Ray, C.

    2006-12-01

    Analyses of stable isotopes of lead (206Pb/207Pb) as well as lead concentrations in soil sediments provide a method to discern anthropogenic from natural sources of lead deposition. In order to distinguish natural from anthropogenic aerosol deposition over the Holocene in Northern New Mexico, isotopic analyses and total lead measurements were performed on bog sediments spanning 15,000 years before present. The bog core was collected in the Santa Fe National Forest at an elevation of 2925 m and comprises a depth of ~400 cm of sediments. Dry and homogenized sediments from depth intervals varying from 2 to 20 cm were extracted in a microwave-assisted digestion with nitric acid at 170 Celsius degree. The accuracy and precision of our method were determined by analyses of standard reference materials (National Institute of Standards and Technology 981, International Atomic Energy Agency (IAEA)-SL-1 and IAEA-soil-7) and replicated measurements respectively. The preliminary results from this study have shown influences from regional anthropogenic sources as well as environmental forcing on the lead concentrations and isotopic signatures. The dominant signals in this environment are believed to be the result of local conditions of the sediments through the Holocene (e.g. dry versus wet/bog environments). This will have a significant impact on lead concentration and isotope modeling as local environmental condition is the dominant control of these proxies.

  11. Changes in anthropogenic nitrogen and phosphorus inputs to the St. Lawrence sub-basin over 110 years and impacts on riverine export

    NASA Astrophysics Data System (ADS)

    Goyette, Jean-Olivier; Bennett, Elena M.; Howarth, Robert W.; Maranger, Roxane

    2016-07-01

    Human activities have increased the flow of nitrogen (N) and phosphorus (P) over much of the Earth, leading to increased agricultural production, but also the degradation of air, soil, and water quality. Here we quantify the sources of anthropogenic N and P inputs to 76 watersheds of the St. Lawrence Basin (SLB) throughout the 20th century using NANI/NAPI (net anthropogenic N/P input to watersheds), a mass balance modeling approach, and estimate the fraction of these inputs exported to adjacent rivers. Our results show that since 1901, NANI and NAPI increased 4.5-fold and 3.8-fold, respectively, with a peak in 1991 mainly due to high atmospheric N deposition and P fertilizer application. However, the relative increase over the course of the last century was much higher in certain watersheds, particularly those where there was greater urbanization. Ranges in NANI and NAPI vary greatly among watersheds (110 to 9351 kg N km-2 yr-1 and 0.16 to 1938 kg P km-2 yr-1, respectively in 2011) and are strongly related to riverine fluxes (R2 = 0.87 and 0.71 for N and P, respectively). Our results suggest that 22% of NANI (ranging from 11% to 68% across watersheds) and 17% of NAPI (ranging from 3% to 173%) are exported to rivers. Predominant sources of inputs vary spatially and through time largely due to changes in farming practices. By tracking the main sources of inputs to specific watersheds and through time, our work provides insights for N and P management. Reduction strategies will likely need to be watershed specific, although through time, our results clearly show the large-scale impact of targeted legislation.

  12. Eolian inputs of lead to the North Pacific

    SciTech Connect

    Jones, C.E.; Halliday, A.N.; Rea, D.K.; Owen, R.M.

    2000-04-01

    The authors evaluate the importance of natural eolian Pb to the dissolved oceanic Pb budget by measuring the isotopic composition of Pb in 35 Holocene and late Quaternary sediment samples from the North Pacific and in 10 samples of Chinese loess. When the Pacific is divided into sediments provinces based on published {var_epsilon}{sub Nd} and sedimentological data, Pb from the central North Pacific tends to be the most radiogenic and homogeneous due to the dominance of eolian Chinese loess. Lead from the marginal North Pacific and the sparsely sampled regions south of 5{degree}N are less radiogenic and more variable owing to hemipelagic inputs from various volcanic arcs and older continental crust located around the Pacific Rim. {sup 208}Pb/{sup 204}Pb ratios provide the most distinctive provenance information due to the relatively high ratios in Chinese loess. The Chinese loess samples come from 3 localities and span up to 2 Myr of time. Acetic-acid leachate, bulk loess, and loess silicate fractions were analyzed separately. Leachate Pb is considerably less radiogenic than silicate Pb. The isotopic composition of the silicate component closely matches the sediment data from the central North Pacific, confirming the dominance of eolian loess in this region. The authors divided up a suite of published hydrogenous Pb-isotope data from the Pacific Ocean according to their locations within the three independently defined sediment provinces. These data define three distinct fields differentiated primarily by their {sup 206}Pb/{sup 204}Pb ratios, which increase going form the Central to Southern to Marginal provinces. This relationship with sediment province strongly suggests that natural eolian and probably hemipelagic inputs significantly impact the seawater Pb budget. Direct support for the dominance of eolian Chinese loess in the central North Pacific dissolved Pb budget comes from the close match between loess leachate Pb and the Central Province hydrogenous Pb data

  13. Anthropogenic lead concentrations and sources in Baltic Sea sediments based on lead isotopic composition.

    PubMed

    Zaborska, Agata

    2014-08-15

    The Gulf of Gdańsk is influenced by heavy metals of anthropogenic origin. In this study, temporal concentration changes of Pb, Zn, Cd, and Cu were studied in six, 50 cm long sediment cores. The main aim of the study was to concentrate on the history of Pb fluxes and Pb isotopic composition ((206)Pb/(207)Pb and (208)Pb/(206)Pb) to trace Pb sources. The lowest Pb concentrations (19 μg g(-1)) were measured in sediments deposited circa 1860, while the highest Pb concentrations (63-147 μg g(-1)) were measured in sediments deposited between 1960s and 70s. Pre-industrial Pb fluxes were 7 Pb m(2)year(-1), while after WWII they reached 199 Pb m(2)year(-1). Highest (206)Pb/(207)Pb ratios (∼1.22) were measured in the oldest sediment layers, and the lowest (206)Pb/(207)Pb ratios (∼1.165) were measured in the sediments deposited in 1970s-90s. During the period of highest Pb contamination, the anthropogenic Pb fraction reached up to 93%. A general discussion of the Pb sources, emissions, and loads for Poland is included. Copyright © 2014 Elsevier Ltd. All rights reserved.

  14. Reconstruction of pollutant lead transport and input in the western north atlantic area during the past century

    NASA Astrophysics Data System (ADS)

    Desenfant, F.; Camoin, G. F.; Veron, A.

    2003-04-01

    There are only few available proxies for marine transport of continental aerosols. Although pelagic sediments can record past deposition, they are not suitable for seasonal and/or interannual detailed records due to low sedimentation rates. We have studied trace metal deposition and associated air mass circulation based on coral records. Indeed, the skeleton of zooxanthellate scleractinian corals represents a potentially important database for the record of environmental parameters. It is used more frequently for paleoenvirronment reconstruction so far in tropical zones, for which only a few sources of information are available. Shen et al (1988 -- Chemical Geology) have demonstrated the capability of these coral skeletons to record anthropogenic lead transport and deposition to the North American basin, in Bermuda. We have collected massive corals from the Caribbean in order to determine the anthropogenic impact of industrial emissions in the western North Atlantic during the past century. Sources and atmospheric circulation are considered at regional and basin scale depending on the location of the sampling sites in the northern (Puerto Rico) and western (Martinique, Guadeloupe) Caribbean. Here we use the capability of lead and its stable isotopes to trace the continental origin of anthropogenic sources and its transport within the North Atlantic troposphere. Measurements of lattice bound lead in sequential coral bands have revealed temporal changes in lead concentration and lead isotope ratios. Anthropogenic perturbations are clearly evidenced at all sites of the Caribbean area, linked to increase of industrial activities and the use of leaded gasoline in the US and Western Europe. Specific variations are related to regional inputs and seasonal changes in air mass circulation. The latter are determined and coupled to lead variations using stable isotope records (O) and meteorological index (North Atlantic Oscillation). Such coral records also provide reliable

  15. Anthropogenic impact and lead pollution throughout the Holocene in Southern Iberia.

    PubMed

    García-Alix, A; Jimenez-Espejo, F J; Lozano, J A; Jiménez-Moreno, G; Martinez-Ruiz, F; García Sanjuán, L; Aranda Jiménez, G; García Alfonso, E; Ruiz-Puertas, G; Anderson, R Scott

    2013-04-01

    Present day lead pollution is an environmental hazard of global proportions. A correct determination of natural lead levels is very important in order to evaluate anthropogenic lead contributions. In this paper, the anthropogenic signature of early metallurgy in Southern Iberia during the Holocene, more specifically during the Late Prehistory, was assessed by mean of a multiproxy approach: comparison of atmospheric lead pollution, fire regimes, deforestation, mass sediment transport, and archeological data. Although the onset of metallurgy in Southern Iberia is a matter of controversy, here we show the oldest lead pollution record from Western Europe in a continuous paleoenvironmental sequence, which suggests clear lead pollution caused by metallurgical activities since ~3900 cal BP (Early Bronze Age). This lead pollution was especially important during Late Bronze and Early Iron ages. At the same time, since ~4000 cal BP, an increase in fire activity is observed in this area, which is also coupled with deforestation and increased erosion rates. This study also shows that the lead pollution record locally reached near present-day values many times in the past, suggesting intensive use and manipulation of lead during those periods in this area.

  16. Isotopic signatures of eelgrass (Zostera marina L.) as bioindicator of anthropogenic nutrient input in the western Baltic Sea.

    PubMed

    Schubert, Philipp R; Karez, Rolf; Reusch, Thorsten B H; Dierking, Jan

    2013-07-15

    Eutrophication is a global environmental problem. Better management of this threat requires more accurate assessments of anthropogenic nitrogen (N) inputs to coastal systems than can be obtained with traditional measures. Recently, primary producer N isotopic signatures have emerged as useful proxy of such inputs. Here, we demonstrated for the first time the applicability of this method using the widespread eelgrass (Zostera marina) in the highly eutrophic Baltic Sea. Spatial availability of sewage N across a bay with one major sewage outflow predicted by eelgrass δ(15)N was high near and downstream of the outflow compared to upstream, but returned to upstream levels within 4 km downstream from the outfall. General conclusions were corroborated by traditional eutrophication measures, but in contrast to these measures were fully quantitative. Eelgrass N isotope ratios therefore show high potential for coastal screens of eutrophication in the Baltic Sea, and in other areas with eelgrass meadows.

  17. Sedimentary record of anthropogenic metal inputs in the Tagus prodelta (Portugal)

    NASA Astrophysics Data System (ADS)

    Mil-Homens, M.; Branco, V.; Vale, C.; Boer, W.; Alt-Epping, U.; Abrantes, F.; Vicente, M.

    2009-02-01

    Favourable oceanographic and environmental conditions allow the formation of a fine-grained deposit (Tagus prodelta) located at the mouth of the Tagus River. This fine-grained deposit results from the sink and accumulation of terrestrial and marine-derived materials. Three short sediment cores collected in the Tagus prodelta were investigated through the variability in grain-size, major and trace elements, C org, N tot, δ13C and 210Pb dating to characterise the historical development of trace metal contamination. Historical trends indicated significant anthropogenic enrichments for Hg, Pb, Zn, Cu, Sb and Sn since the 1930s. Hg presents the highest level of anthropogenic enrichment (ca. EF Hg=20) in cores 3576 (PO287-26-1B) and 3579 (PO287-27-1B) collected closer to the shore. Despite these elements were derived from distinct industrial sources, all of them presented similar temporal trends, which points to the importance of estuarine mixing processes originated by the tidal regime and wind before transfer to the adjoining coastal areas. The cores were characterised by smoothness of down-core variations and river flood events occurred in the last decades were not registered. Furthermore, the improvement of effluents treatment together with the closing of some industrial point sources in the last two decades is not evidenced in recent sediment composition of the Tagus prodelta. Besides sediment reworking in the upper sediment layers, sediment mixing inside the estuary may explain minor abrupt alterations with the depth.

  18. USING MUSSEL ISTOPE RATIOS TO ASSESS ANTHROPOGENIC NITROGEN INPUTS TO FRESHWATER ECOSYSTEMS

    EPA Science Inventory

    Stable nitrogen isotope ratios ( 15N) of freshwater mussels from a series of lakes and ponds were related to watershed land use characteristics to assess their utility in determining the source of nitrogen inputs to inland water bodies. Nitrogen isotope ratios measured in freshwa...

  19. USING MUSSEL ISTOPE RATIOS TO ASSESS ANTHROPOGENIC NITROGEN INPUTS TO FRESHWATER ECOSYSTEMS

    EPA Science Inventory

    Stable nitrogen isotope ratios ( 15N) of freshwater mussels from a series of lakes and ponds were related to watershed land use characteristics to assess their utility in determining the source of nitrogen inputs to inland water bodies. Nitrogen isotope ratios measured in freshwa...

  20. USING MUSSEL ISOTOPE RATIOS TO ASSESS ANTHROPOGEN NITROGEN INPUTS TO COASTAL ECOSYSTEMS

    EPA Science Inventory

    The stable nitrogen isotope ratio in ribbed mussel (Geukensia demissus) tissue was investigated as an indicator of the source of nitrogen inputs to coastal salt marshes. Mussels fed a diet of 15N enriched algae in the laboratory showed an increase in tissue nitrogen isotope rati...

  1. Anthropogenic point-source and non-point-source nitrogen inputs into Huai River basin and their impacts on riverine ammonia-nitrogen flux

    NASA Astrophysics Data System (ADS)

    Zhang, W. S.; Swaney, D. P.; Li, X. Y.; Hong, B.; Howarth, R. W.; Ding, S. H.

    2015-07-01

    This study provides a new approach to estimate both anthropogenic non-point-source and point-source nitrogen (N) inputs to the landscape, and determines their impacts on riverine ammonia-nitrogen (AN) flux, providing a foundation for further exploration of anthropogenic effects on N pollution. Our study site is Huai River basin of China, a water-shed with one of the highest levels of N input in the world. Multi-year average (2003-2010) inputs of N to the watershed are 27 200 ± 1100 kg N km-2 yr-1. Non-point sources comprised about 98 % of total N input, and only 2 % of inputs are directly added to the aquatic ecosystem as point sources. Fertilizer application was the largest non-point source of new N to the Huai River basin (69 % of net anthropogenic N inputs), followed by atmospheric deposition (20 %), N fixation in croplands (7 %), and N content of imported food and feed (2 %). High N inputs showed impacts on riverine AN flux: fertilizer application, point-source N input, and atmospheric N deposition were proved as more direct sources to riverine AN flux. Modes of N delivery and losses associated with biological denitrification in rivers, water consumption, interception by dams may influence the extent of export of riverine AN flux from N sources. Our findings highlight the importance of anthropogenic N inputs from both point sources and non-point sources in heavily polluted watersheds, and provide some implications for AN prediction and management.

  2. Anthropogenic point and non-point nitrogen inputs into Huai River Basin and their impacts on riverine ammonia-nitrogen flux

    NASA Astrophysics Data System (ADS)

    Zhang, W. S.; Swaney, D. P.; Li, X. Y.; Hong, B.; Howarth, R. W.; Ding, S. H.

    2015-02-01

    This study provides a new approach to estimate both anthropogenic non-point and point nitrogen (N) inputs to the landscape, and determines their impacts on riverine ammonia-nitrogen (AN) flux, providing a foundation for further exploration of anthropogenic effects on N pollution. Our study site is Huai River Basin of China, a watershed with one of the highest levels of N input in the world. Multi-year average (2003-2010) inputs of N to the watershed are 27 200 ± 1100 kg N km-2 yr-1. Non-point sources comprised about 98% of total N input and only 2% of inputs are directly added to the aquatic ecosystem as point sources. Fertilizer application was the largest non-point source of new N to the Huai River Basin (69% of net anthropogenic N inputs), followed by atmospheric deposition (20%), N fixation in croplands (7%), and N content of imported food and feed (2%). High N inputs showed impacts on riverine AN flux: fertilizer application, point N input and atmospheric N deposition were proved as more direct sources to riverine AN flux. Modes of N delivery and losses associated with biological denitrification in rivers, water consumption, interception by dams influenced the extent of export of riverine AN flux from N sources. Our findings highlight the importance of anthropogenic N inputs from point and non-point sources in heavily polluted watersheds, and provide some implications for AN prediction and management.

  3. Assessment of multiple sources of anthropogenic and natural chemical inputs to a morphologically complex basin, Lake Mead, USA

    USGS Publications Warehouse

    Rosen, Michael R.; Van Metre, P.C.

    2010-01-01

    Lakes with complex morphologies and with different geologic and land-use characteristics in their sub-watersheds could have large differences in natural and anthropogenic chemical inputs to sub-basins in the lake. Lake Mead in southern Nevada and northern Arizona, USA, is one such lake. To assess variations in chemical histories from 1935 to 1998 for major sub-basins of Lake Mead, four sediment cores were taken from three different parts of the reservoir (two from Las Vegas Bay and one from the Overton Arm and Virgin Basin) and analyzed for major and trace elements, radionuclides, and organic compounds. As expected, anthropogenic contaminant inputs are greatest to Las Vegas Bay reflecting inputs from the Las Vegas urban area, although concentrations are low compared to sediment quality guidelines and to other USA lakes. One exception to this pattern was higher Hg in the Virgin Basin core. The Virgin Basin core is located in the main body of the lake (Colorado River channel) and is influenced by the hydrology of the Colorado River, which changed greatly with completion of Glen Canyon Dam upstream in 1963. Major and trace elements in the core show pronounced shifts in the early 1960s and, in many cases, gradually return to concentrations more typical of pre-1960s by the 1980s and 1990s, after the filling of Lake Powell. The Overton Arm is the sub-basin least effected by anthropogenic contaminant inputs but has a complex 137Cs profile with a series of large peaks and valleys over the middle of the core, possibly reflecting fallout from nuclear tests in the 1950s at the Nevada Test Site. The 137Cs profile suggests a much greater sedimentation rate during testing which we hypothesize results from greatly increased dust fall on the lake and Virgin and Muddy River watersheds. The severe drought in the southwestern USA during the 1950s might also have played a role in variations in sedimentation rate in all of the cores. ?? 2009.

  4. Metal contents in Porites corals: Anthropogenic input of river run-off into a coral reef from an urbanized area, Okinawa.

    PubMed

    Ramos, A A; Inoue, Y; Ohde, S

    2004-02-01

    In order to monitor pollutants from urban areas to coral reefs, metal contents in Porites coral samples collected from the Hija River mouth and at nearby sites from the estuary were analyzed. The corals were cleaned by oxidative and reductive treatments to effectively eliminate detritus and organic materials. Metal-to-calcium (Me/Ca) ratios in the samples were determined by ICP-MS. Filtered samples of river water were also measured similarly for metal concentrations. The extent of anthropogenic contribution by riverine input was assessed by comparing the Me/Ca values in corals to those of Rukan-sho, an unpolluted coral reef. High riverine inputs of Mn, Cd, Zn and Ag were observed from Me/Ca values in the coral samples. Manganese in the coral samples showed strong dependence on salinity, varying inversely to the distance from terrestrial sources. Considering a lead background of 25.0 nmol/mol measured in the Rukan-sho corals, Pb/Ca in corals of the Hija River estuary that are two and three times higher may indicate lead enrichment in the river mouth. Because Pb is only moderately high in the Hija River water compared to its concentration in surface seawater, lead may have accumulated in the estuarine water and sediments, resulting in an elevated concentration of lead available for coral uptake.

  5. Significance of natural and anthropogenic sediment inputs to the saguenay Fjord, Quebec

    NASA Astrophysics Data System (ADS)

    Schafer, C. T.; Smith, J. N.; Seibert, G.

    1983-11-01

    One-centimeter interval Pb-210 dating and 4-cm interval size analysis was carried out on a sediment core collected in a prodelta depositional environment near the head of the Saguenay Fjord. Results show a direct relationship between modal diameter of the sand fraction and annual maximum mean monthly river discharge events that are usually associated with the spring freshet. Indirect evidence of sediment flux to the head of the fjord includes a series of sand waves that are developed on a prograding submarine delta at the mouth of the Saguenay River. Clay-pellet zones observed in a gravity core are related to catastrophic events such as the 1971 St. Jean Vianney landslide, or to anthropogenic activities associated with the construction of dams and powerhouses at upriver locations. A subtle change in the slope of a graph relating cumulative annual mean river discharge and sediment accumulation for the 1950-1970 interval is in agreement with the timing of dam construction on the lower reaches of the Saguenay River system.

  6. Lead Isotopic Tracing of Coal-Based Anthropogenic Pollution in Agricultural Soils in Jianghan Plain, China

    NASA Astrophysics Data System (ADS)

    Daniel, J. N.; Ying, S.; Zhao, R.; Bu, J.; Gan, Y.; Wang, Y.; Weiss, D. J.; Fendorf, S. E.

    2014-12-01

    The Chinese demand for energy is one of the greatest in the world, and the vast majority of it is generated through coal combustion - a process by which diverse pollutants are released into the atmosphere. Due to the relative proximity of croplands to power plants in much of China, these pollutants can be deposited onto agricultural soils via atmospheric transport. Relative amounts of lead (Pb) isotopes in airborne anthropogenic coal-based contaminants (fly ash) are currently understood. However, contaminants' effects on agricultural soil composition are less clear. We investigate the prevalence of anthropogenic contaminants in cropland soils using lead (Pb) isotope ratios as a tracer. Surface soil samples and deep core samples, taken from Chinese field sites in proximity to a coal combustion plant, undergo an acid extraction process and lead (Pb) isotope concentrations are measured. The results of this study illustrate the extent to which airborne contaminants have entered cropland soils and integrated themselves into the chemical processes at work. They further expand our understanding of the impacts of human coal combustion activities on the biogeochemistry of agricultural soils.

  7. Asian anthropogenic lead contamination in the North Pacific Ocean as evidenced by stable lead isotopic compositions

    NASA Astrophysics Data System (ADS)

    Zurbrick, Cheryl M.

    This dissertation work determined the changing scope of lead (Pb) contamination in the North Pacific Ocean since the phase-out of leaded gasoline in most of the world. Chapters 1 and 2 consisted of validating our method for determining Pb concentrations and isotopic compositions in seawater. Chapter 3 established a baseline of Pb isotopic compositions (PbICs) in the western and central North Pacific in 2002. This was an ideal time to establish such a baseline because China had recently (mid-2000) ceased their use of leaded gasoline and simultaneously began consuming increasingly large amounts of coal, known to have relatively high Pb concentrations. We found subsurface waters were contaminated with Asian industrial Pb, predominantly Chinese coal emissions. In contrast, the abyssal waters were a mix of Asian industrial Pb and background (i.e., natural) Pb. Chapter 4 revisited the western and central North Pacific in 2009 -- 2011 to determine what, if any, changes had occurred in this short time period. We found that Pb in subsurface and abyssal waters of the western North Pacific were similar to Chinese aerosols. Such a large change in the PbICs of abyssal water in 9 years was unanticipated and attributed to the relatively large flux of particle-bound Pb from the euphotic zone to the deep ocean, which was in isotopic equilibrium with the reservoir of dissolved Pb. In contrast, the central North Pacific abyssal water PbICs were similar to values previously reported because of the relatively lower particulate export. Based on comparisons to baseline PbIC data, we determined that abyssal waters in the western and central North Pacific would be isotopically indistinguishable from surface waters in the next three decades. Sources of Pb to coastal California waters were reevaluated in Chapter 5. Prior studies had found that surface waters of the California Current System (CCS) were isotopically consistent with both Asian industrial Pb and US leaded gasoline, still in use

  8. Evaluating cumulative effects of anthropogenic inputs in Prince Edward Island estuaries using the mummichog (Fundulus heteroclitus).

    PubMed

    Finley, Megan A; Courtenay, Simon C; Teather, Kevin L; Hewitt, L Mark; Holdway, D A; Hogan, Natacha S; van den Heuvel, Michael R

    2013-07-01

    suggestive of a potential chemical effect. Eutrophication appeared to be a primary stressor affecting mummichog populations, as nutrient enrichment was associated with changes in habitat variables and these in turn were associated with high mummichog density. Thus, mummichog population demographics appear to have use as an indicator of adverse or worsening conditions in estuaries. We concluded that, based on the subset of environmental factors evaluated, the nonpoint-source inputs of sediments and nutrients exerted the greatest influence on mummichog populations in PEI estuaries. Copyright © 2013 SETAC.

  9. Isotopic identification of natural vs. anthropogenic lead sources in marine sediments from the inner Ría de Vigo (NW Spain).

    PubMed

    Álvarez-Iglesias, P; Rubio, B; Millos, J

    2012-10-15

    San Simón Bay, the inner part of the Ría de Vigo (NW Spain), an area previously identified as highly polluted by Pb, was selected for the application of Pb stable isotope ratios as a fingerprinting tool in subtidal and intertidal sediment cores. Lead isotopic ratios were determined by inductively coupled plasma mass spectrometry on extracts from bulk samples after total acid digestion. Depth-wise profiles of (206)Pb/(207)Pb, (206)Pb/(204)Pb, (207)Pb/(204)Pb, (208)Pb/(204)Pb and (208)Pb/(207)Pb ratios showed, in general, an upward decrease for both intertidal and subtidal sediments as a consequence of the anthropogenic activities over the last century, or centuries. Waste channel samples from a nearby ceramic factory showed characteristic Pb stable isotope ratios different from those typical of coal and petrol. Natural isotope ratios from non-polluted samples were established for the study area, differentiating sediments from granitic or schist-gneiss sources. A binary mixing model employed on the polluted samples allowed estimating the anthropogenic inputs to the bay. These inputs represented between 25 and 98% of Pb inputs in intertidal samples, and 9-84% in subtidal samples, their contributions varying with time. Anthropogenic sources were apportioned according to a three-source model. Coal combustion-related emissions were the main anthropogenic source Pb to the bay (60-70%) before the establishment of the ceramic factory in the area (in the 1970s) which has since constituted the main source (95-100%), followed by petrol-related emissions. The Pb inputs history for the intertidal area was determined for the 20th century, and, for the subtidal area, the 19th and 20th centuries.

  10. Atmospheric black carbon in the Russian Arctic: anthropogenic inputs in comparison with average or extremal wood fires' ones

    NASA Astrophysics Data System (ADS)

    Vinogradova, Anna A.; Smirnov, Nikolay S.; Korotkov, Vladimir N.

    2016-04-01

    Model estimates of atmospheric black carbon concentrations were made for different points of the Russian Arctic. Anthropogenic BC emissions and wood fires' ones were calculated from Russian official statistics for the 2000s. We used the data of Ministry of Natural Resources and Environment of RF on anthropogenic air emissions of pollution in Russian cities and regions [1], as well as the data of Federal Forestry Agency of RF (Rosleshoz) [2] on wood fires. We considered the area within (50-72)N and (20-180)E, which covers about 94% of the Russian territory, where both anthropogenic and fire BC emissions have been arranged through grid cells (1×1) deg. Anthropogenic BC emissions are estimated as annual values based on the data for 54 regions and more than 100 cities. Total emission is estimated as (220 ± 30) Gg BC in 2010 [3], including emissions from open flares associated with gas/oil extractive industry which are about (25 ± 8) Gg/yr. We analyzed the data on wood fires (detailing crown, ground and underground fires in forests and fires on non-forest lands) with their spatial and seasonal variations during 15 years (2000-2014). Different combustion factors [4] and BC emission coefficients [5] were used in calculations for different types of burning. Russian total average annual BC emission from fires, occurring mainly in summertime, was estimated as 30 Gg with large variations (4-100 Gg/yr) from year to year. Asian territory emits about 90% of this value. We estimated anthropogenic (BC_A) and fires' (BC_F) contributions to BC air concentrations at different Russian Arctic points using the approach [6] - decadal back-trajectory analysis combined with spatial distribution of sensitivity pollution emission function (SPEF). Extraordinary atmospheric circulation causing, to a great extent, abnormally intensive fires in the middle latitudes often leads to a decrease in SPEF values for these territories. As a result, fires are not so dangerous for the whole Arctic, as

  11. Anthropogenic lead distribution in rodent-affected and undisturbed soils in southern California

    SciTech Connect

    Mace, J.E.; Graham, R.C.; Amrhein, C.

    1997-01-01

    Anthropogenic Pb is the world`s largest and most widespread heavy metal contamination. Inspired by recent evidence suggesting a faster redistribution of Pb through the mineral soil profile than was previously expected, we investigated the effects of rodent activity on Pb redistribution. Total Pb was analyzed at the 0-1, 1-4, and 4-7-cm depths in a rodent-affected soil and in an undisturbed soil, in the same proximity and with the same parent material, in the Box Springs Mountains near Riverside, California. Six replicate sites of each condition were sampled. Lead was recovered by a digest in 4 M HNO{sub 3} and measured using a graphite furnace atomic absorption spectrophotometer. Anthropotenic Pb content to a 7-cm depth averaged 19 mg kg{sup -1} in undisturbed soils and 10 mg kg{sup -1} in rodent-affected soils. In both soils, the highest concentrations of Pb were located in the top 4 cm of the profile. After accounting for an estimated native Pb ({approximately}3.3 mg kg{sup -1}), we determined that 20 to 38 kg ha{sup -1} Pb has been deposited on these soils, through air pollution. Our findings suggest rodents significantly modify the distribution of anthropogenic Pb in the rodent-affected soils of the box Springs Mountains primarily in two ways: (i) by reducing Pb concentration in surface soils, thereby decreasing the potential for erosional redistribution of Pb, and (ii) by decreasing Pb transport time through the soil profile as a result of physical mixing. This redistribution mechanism is likely applicable to other surface deposited anthropogenic contaminants that have similarly low soil mobility. 18 refs., 1 fig., 2 tabs.

  12. Fate of Upstream Anthropogenic Nitrogen Inputs in a Tropical Catchment, Athi-Galana-Sabaki River, Kenya.

    NASA Astrophysics Data System (ADS)

    Marwick, Trent R.

    2013-04-01

    blooms downstream highlight the significant role of primary producers assimilating DIN lower in the drainage network. The intense upstream N-cycling leads to a significantly enriched δ15NPN during the dry season (mean: 16.5 ± 8.2‰) comparative to the short (7.3 ± 2.6‰) and long (7.6 ± 5.9‰) rain seasons. The strong correlation found between seasonal δ15NPN and δ18OH2O (δ18OH2O as a proxy of discharge; p = 0.0258, n = 26) presents the possibility of employing a combination of proxies such as δ15NPN of sediments, corals and bivalves, to build the foundation of how historical land-use changes have influenced nitrogen cycling within the catchment whilst potentially providing foresight for future land management decisions.

  13. Net anthropogenic nitrogen inputs (NANI) into the Yangtze River basin and the relationship with riverine nitrogen export

    NASA Astrophysics Data System (ADS)

    Chen, Fei; Hou, Lijun; Liu, Min; Zheng, Yanling; Yin, Guoyu; Lin, Xianbiao; Li, Xiaofei; Zong, Haibo; Deng, Fengyu; Gao, Juan; Jiang, Xiaofen

    2016-02-01

    This study investigated net anthropogenic nitrogen inputs (NANI, including atmospheric nitrogen deposition, nitrogenous fertilizer use, net nitrogen import in food and feed, and agricultural nitrogen fixation) and the associated relationship with riverine dissolved inorganic nitrogen (DIN) export in the Yangtze River basin during the 1980-2012 period. The total NANI in the Yangtze River basin has increased by more than twofold over the past three decades (3537.0 ± 615.3 to 8176.6 ± 1442.1 kg N km-2 yr-1). The application of chemical fertilizer was the largest component of NANI in the basin (51.1%), followed by net nitrogen import in food and feed (26.0%), atmospheric nitrogen deposition (13.2%), and agricultural nitrogen fixation (9.7%). A regression analysis showed that the riverine DIN export was strongly correlated with NANI and the annual water discharge (R2 = 0.90, p < 0.01). NANI in the Yangtze River basin was estimated to contribute 37-66% to the riverine DIN export. We also forecasted future variations in NANI and riverine DIN export for the years 2013 to 2030, based on possible future changes in human activities and the climate. This work provides a quantitative understanding of NANI in the Yangtze River basin and its effects on riverine DIN export and helps to develop integrated watershed nitrogen management strategies.

  14. Influence of lag effect, soil release, and climate change on watershed anthropogenic nitrogen inputs and riverine export dynamics.

    PubMed

    Chen, Dingjiang; Huang, Hong; Hu, Minpeng; Dahlgren, Randy A

    2014-05-20

    This study demonstrates the importance of the nitrogen-leaching lag effect, soil nitrogen release, and climate change on anthropogenic N inputs (NANI) and riverine total nitrogen (TN) export dynamics using a 30-yr record for the Yongan River watershed in eastern China. Cross-correlation analysis indicated a 7-yr, 5-yr, and 4-yr lag time in riverine TN export in response to changes in NANI, temperature, and drained agricultural land area, respectively. Enhanced by warmer temperature and improved agricultural drainage, the upper 20 cm of agricultural soils released 270 kg N ha(-1) between 1980 and 2009. Climate change also increased the fractional export of NANI to river. An empirical model (R(2) = 0.96) for annual riverine TN flux incorporating these influencing factors estimated 35%, 41%, and 24% of riverine TN flux originated from the soil N pool, NANI, and background N sources, respectively. The model forecasted an increase of 45%, 25%, and 6% and a decrease of 13% in riverine TN flux from 2010 to 2030 under continued development, climate change, status-quo, and tackling scenarios, respectively. The lag effect, soil N release, and climate change delay riverine TN export reductions with respect to decreases in NANI and should be considered in developing and evaluating N management measures.

  15. Arsenic in New Jersey Coastal Plain streams, sediments, and shallow groundwater: effects from different geologic sources and anthropogenic inputs on biogeochemical and physical mobilization processes

    USGS Publications Warehouse

    Barringer, Julia L.; Reilly, Pamela A.; Eberl, Dennis D.; Mumford, Adam C.; Benzel, William M.; Szabo, Zoltan; Shourds, Jennifer L.; Young, Lily Y.

    2013-01-01

    With a history of agriculture in the New Jersey Coastal Plain, anthropogenic inputs of As, such as residues from former pesticide applications in soils, can amplify any geogenic As in runoff. Such inputs contribute to an increased total As load to a stream at high stages of flow. As a result of yet another anthropogenic influence, microbes that reduce and mobilize As beneath the streambeds are stimulated by inputs of dissolved organic carbon (DOC). Although DOC is naturally occurring, anthropogenic contributions from wastewater inputs may deliver increased levels of DOC to subsurface soils and ultimately groundwater. Arsenic concentrations may increase with the increases in pH of groundwater and stream water in developed areas receiving wastewater inputs, as As mobilization caused by pH-controlled sorption and desorption reactions are likely to occur in waters of neutral or alkaline pH (for example, Nimick and others, 1998; Barringer and others, 2007b). Because of the difference in As content of the geologic materials in the two sub-provinces of the Coastal Plain, the amount of As that is mobile in groundwater and stream water is, potentially, substantially greater in the Inner Coastal Plain than in the Outer Coastal Plain. In turn, streams within the Inner and Outer Coastal Plain can receive substantially more As in groundwater discharge from developed areas than from environments where DOC appears to be of natural origin.

  16. Assessment of anthropogenic inputs in the surface waters of the southern coastal area of Sfax during spring (Tunisia, Southern Mediterranean Sea).

    PubMed

    Drira, Zaher; Kmiha-Megdiche, Salma; Sahnoun, Houda; Hammami, Ahmed; Allouche, Noureddine; Tedetti, Marc; Ayadi, Habib

    2016-03-15

    The coastal marine area of Sfax (Tunisia), which is well-known for its high productivity and fisheries, is also subjected to anthropogenic inputs from diverse industrial, urban and agriculture activities. We investigated the spatial distribution of physical, chemical and biogeochemical parameters in the surface waters of the southern coastal area of Sfax. Pertinent tracers of anthropogenic inputs were identified. Twenty stations were sampled during March 2013 in the vicinity of the coastal areas reserved for waste discharge. Phosphogypsum wastes dumped close to the beaches were the main source of PO4(3-), Cl(-) and SO4(2-) in seawater. The high content in total polyphenolic compounds was due to the olive oil treatment waste water released from margins. These inorganic and organic inputs in the surface waters were associated with elevated COD. The BOD5/COD (<0.5) and COD/BOD5 (>3) ratios highlighted a chemical pollution with organic load of a low biodegradability.

  17. Anthropogenic influences on the input and biogeochemical cycling of nutrients and mercury in Great Salt Lake, Utah, USA

    USGS Publications Warehouse

    Naftz, D.; Angeroth, C.; Kenney, T.; Waddell, B.; Darnall, N.; Silva, S.; Perschon, C.; Whitehead, J.

    2008-01-01

    Despite the ecological and economic importance of Great Salt Lake (GSL), little is known about the input and biogeochemical cycling of nutrients and trace elements in the lake. In response to increasing public concern regarding anthropogenic inputs to the GSL ecosystem, the US Geological Survey (USGS) and US Fish and Wildlife Service (USFWS) initiated coordinated studies to quantify and evaluate the significance of nutrient and Hg inputs into GSL. A 6??? decrease in ??15N observed in brine shrimp (Artemia franciscana) samples collected from GSL during summer time periods is likely due to the consumption of cyanobacteria produced in freshwater bays entering the lake. Supporting data collected from the outflow of Farmington Bay indicates decreasing trends in ??15N in particulate organic matter (POM) during the mid-summer time period, reflective of increasing proportions of cyanobacteria in algae exported to GSL on a seasonal basis. The C:N molar ratio of POM in outflow from Farmington Bay decreases during the summer period, supportive of the increased activity of N fixation indicated by decreasing ??15N in brine shrimp and POM. Although N fixation is only taking place in the relatively freshwater inflows to GSL, data indicate that influx of fresh water influences large areas of the lake. Separation of GSL into two distinct hydrologic and geochemical systems from the construction of a railroad causeway in the late 1950s has created a persistent and widespread anoxic layer in the southern part of GSL. This anoxic layer, referred to as the deep brine layer (DBL), has high rates of SO42 - reduction, likely increasing the Hg methylation capacity. High concentrations of methyl mercury (CH3Hg) (median concentration = 24 ng/L) were observed in the DBL with a significant proportion (31-60%) of total Hg in the CH3Hg form. Hydroacoustic and sediment-trap evidence indicate that turbulence introduced by internal waves generated during sustained wind events can temporarily mix the

  18. Lead sources to California sea otters: Industrial inputs circumvent natural lead biodepletion mechanisms

    SciTech Connect

    Smith, D.R.; Flegal, A.R. ); Niemeyer, S. )

    1992-04-01

    Lead levels (as Pb/Ca atom ratios) and stable isotopic compositions were measured in teeth of preindustrial and contemporary California sea otters (Enhydra lutris) to determine if postindustrial changes had occurred in the magnitude and source of accumulated lead. Lead/calcium atom ratios in teeth of some contemporary animals were significantly elevated and compared to level in other contemporary and preindustrial otters. The isotopic ratios revealed a change in the sources of accumulated leads, from natural continental-derived lead in the preindustrial animals ({sup 207}Pb/{sup 206}Pb = 0.820 {plus minus} 0.002) to industrial sources dominated by aerosol lead in the contemporary otters ({sup 207}Pb/{sup 206}Pb = 0.853), who contained lead derived from an industrial waste lead deposit in Monterey Harbor. These data establish distinguishable sources of lead assimilated by sea otters, and indicate that elevated exposures to some animals circumvented the natural biodepletion of lead through marine trophic pathways.

  19. Biogeochemical typology and temporal variability of lagoon waters in a coral reef ecosystem subject to terrigeneous and anthropogenic inputs (New Caledonia).

    PubMed

    Fichez, R; Chifflet, S; Douillet, P; Gérard, P; Gutierrez, F; Jouon, A; Ouillon, S; Grenz, C

    2010-01-01

    Considering the growing concern about the impact of anthropogenic inputs on coral reefs and coral reef lagoons, surprisingly little attention has been given to the relationship between those inputs and the trophic status of lagoon waters. The present paper describes the distribution of biogeochemical parameters in the coral reef lagoon of New Caledonia where environmental conditions allegedly range from pristine oligotrophic to anthropogenically influenced. The study objectives were to: (i) identify terrigeneous and anthropogenic inputs and propose a typology of lagoon waters, (ii) determine temporal variability of water biogeochemical parameters at time-scales ranging from hours to seasons. Combined ACP-cluster analyses revealed that over the 2000 km(2) lagoon area around the city of Nouméa, "natural" terrigeneous versus oceanic influences affecting all stations only accounted for less than 20% of the spatial variability whereas 60% of that spatial variability could be attributed to significant eutrophication of a limited number of inshore stations. ACP analysis allowed to unambiguously discriminating between the natural trophic enrichment along the offshore-inshore gradient and anthropogenically induced eutrophication. High temporal variability in dissolved inorganic nutrients concentrations strongly hindered their use as indicators of environmental status. Due to longer turn over time, particulate organic material and more specifically chlorophyll a appeared as more reliable nonconservative tracer of trophic status. Results further provided evidence that ENSO occurrences might temporarily lower the trophic status of the New Caledonia lagoon. It is concluded that, due to such high frequency temporal variability, the use of biogeochemical parameters in environmental surveys require adapted sampling strategies, data management and environmental alert methods. Copyright (c) 2010 Elsevier Ltd. All rights reserved.

  20. Influence of anthropogenic inputs and a high-magnitude flood event on metal contamination pattern in surface bottom sediments from the Deba River urban catchment.

    PubMed

    Martínez-Santos, Miren; Probst, Anne; García-García, Jon; Ruiz-Romera, Estilita

    2015-05-01

    The purpose of this study was to assess the influence of anthropogenic factors (infrastructure construction and industrial and wastewater inputs) and hydrological factors (high-magnitude flood events) on metal and organic contamination and on the source variability of sediments taken from the Deba River and its tributaries. The pollution status was evaluated using a sequential extraction procedure (BCR 701), enrichment factor, individual and global contamination factors and a number of statistical analysis methods. Zn, Cu and Cr were found to have significant input from anthropogenic sources, with moderately severe enrichment, together with an extremely high potential risk of contamination. The principal scavenger of Cu and Cr was organic matter, whereas Zn was uniformly distributed among all non-residual fractions. For Fe, the anthropogenic contribution was more obviously detected in bulk sediments (<2 mm) than in fine fractions (<63 μm). Finally, the recent construction of a rail tunnel traversing Wealden Facies evaporites, together with intense rainfalls, was the main reason for the change in the source variability of bottom sediments and metal distribution in headwaters. The occurrence of a high-magnitude flood event resulted in a washout of the river bed and led to a general decrease in fine-grained sediment and metal concentrations in labile fractions of channel-bottom sediments, and a consequent downstream transfer of the pollution.

  1. Cascading impacts of anthropogenically driven habitat loss: deforestation, flooding, and possible lead poisoning in howler monkeys (Alouatta pigra).

    PubMed

    Serio-Silva, Juan Carlos; Olguín, Eugenia J; Garcia-Feria, Luis; Tapia-Fierro, Karla; Chapman, Colin A

    2015-01-01

    To construct informed conservation plans, researchers must go beyond understanding readily apparent threats such as habitat loss and bush-meat hunting. They must predict subtle and cascading effects of anthropogenic environmental modifications. This study considered a potential cascading effect of deforestation on the howler monkeys (Alouatta pigra) of Balancán, Mexico. Deforestation intensifies flooding. Thus, we predicted that increased flooding of the Usumacinta River, which creates large bodies of water that slowly evaporate, would produce increased lead content in the soils and plants, resulting in lead exposure in the howler monkeys. The average lead levels were 18.18 ± 6.76 ppm in the soils and 5.85 ± 4.37 ppm in the plants. However, the average lead content of the hair of 13 captured howler monkeys was 24.12 ± 5.84 ppm. The lead levels in the animals were correlated with 2 of 15 blood traits (lactate dehydrogenase and total bilirubin) previously documented to be associated with exposure to lead. Our research illustrates the urgent need to set reference values indicating when adverse impacts of high environmental lead levels occur, whether anthropogenic or natural, and the need to evaluate possible cascading effects of deforestation on primates.

  2. Pollutant lead transport and input to the Caribbean during the 20^{th} century

    NASA Astrophysics Data System (ADS)

    Desenfant, F.; Camoin, G. F.; Véron, A.

    2003-05-01

    Here we evidence significant shifts in the sources of Pb input to the Caribbean based on lead isotope records from massive corals collected near Puerto Rico. While mean Pb/Ca ratios in these corals generally mimic alkyl Pb consumption in the US, we observe a 5 to 8 years delay in the maximum Pb peak in the 1970s. Pollutant Pb decay in corals is not as rapid as expected from the phasing out of leaded gasoline related to European and regional sources. Furthermore, ^{206}Pb/^{207}Pb imprints often display significant interannual variations with no clear temporal evolution. This seems to be partly connected to specific meteorological events and seasonal atmospheric shifts with mixed input from the southern US, Europe and Latin America/Caribbean. New corats from the Western Caribbean (Martinique, Guadeloupe) are presently analysed in order to investigate these isotopic shifts in relation to atmospheric input sources and oceanic recirculation.

  3. Asian industrial lead inputs to the North Pacific evidenced by lead concentrations and isotopic compositions in surface waters and aerosols.

    PubMed

    Gallon, Céline; Ranville, Mara A; Conaway, Christopher H; Landing, William M; Buck, Clifton S; Morton, Peter L; Flegal, A Russell

    2011-12-01

    Recent trends of atmospheric lead deposition to the North Pacific were investigated with analyses of lead in aerosols and surface waters collected on the fourth Intergovernmental Oceanographic Commission Contaminant Baseline Survey from May to June, 2002. Lead concentrations of the aerosols varied by 2 orders of magnitude (0.1-26.4 pmol/m(3)) due in part to variations in dust deposition during the cruise. The ranges in lead aerosol enrichment factors relative to iron (1-119) and aluminum (3-168) were similar, evidencing the transport of Asian industrial lead aerosols across the North Pacific. The oceanic deposition of some of those aerosols was substantiated by the gradient of lead concentrations of North Pacific waters, which varied 3-fold (32.7-103.5 pmol/kg), were highest along with the Asian margin of the basin, and decreased eastward. The hypothesized predominance of Asian industrial lead inputs to the North Pacific was further corroborated by the lead isotopic composition of ocean surface waters ((206)Pb/(207)Pb = 1.157-1.169; (208)Pb/(206)Pb = 2.093-2.118), which fell within the range of isotopic ratios reported in Asian aerosols that are primarily attributed to Chinese industrial lead emissions.

  4. Detection and calibration of anthropogenic lead emission in coastal sediments of China during the past 250 years.

    PubMed

    Zhou, Xin; Sun, Liguang; Liu, Yi; Jia, Nan; Cheng, Wenhan; Wang, Yuhong

    2015-10-01

    The historical fluctuation of lead (Pb) content in coastal sediments of China and its link with human activities have been extensively studied. However, the determined Pb profiles from even the same regions could contradict each other, likely due to the fact that different methods are used in detecting anthropogenic Pb emission. In the present study, we analyzed grain size distribution and Pb levels in three sediment cores from Chinese coastal areas, and observed a significant enrichment of Pb in the sediment fraction of fine grain size. Based upon this observation, we normalized the Pb concentrations during the past 250 years by fine grain size content. The normalized Pb profiles showed consistent, increasing trends in the three cores and a remarkable rise after the Industrial Revolution. The regional characteristics in the normalized Pb profiles of Chinese offshore sediments are consistent with those of terrestrial sediments. This new normalization method is robust and cost-effective for studying anthropogenic Pb emissions in coastal sediments.

  5. Anthropogenic nitrogen input traced by means of delta15N values in macroalgae: results from in-situ incubation experiments.

    PubMed

    Deutsch, Barbara; Voss, Maren

    2006-08-01

    The macroalgae species Fucus vesiculosus (Phaeophyta), Polysiphonia sp., and Ceramium rubrum (Rhodophyta) originally grown at an unpolluted brackish site of the southern Baltic Sea were incubated for 10 and 14 days at 12 stations along a salinity gradient in a highly polluted estuary. We have expected an adaptation of the initially low delta15N values to the higher ones within the incubation period. In addition to the macroalgae the delta15N values of NO3(-) were measured to evaluate fractionation processes of the source nitrate. Inside the estuary, delta15N-NO3(-) values were 6.2-9.7 per thousand, indicating anthropogenic nitrogen sources. The red macroalgae adequately reflected the nitrate isotope values in the surrounding waters, whereas for F. vesiculosus the results were not that clear. The reasons were assumed to be higher initial delta15N values of F. vesiculosus and presumably a too slow nitrogen uptake and growth rate. The method of macroalgae incubations seems suitable as a simple monitoring to study the influence of anthropogenic nitrogen loading in an estuarine environment.

  6. Past leaded gasoline emissions as a nonpoint source tracer in riparian systems: A study of river inputs to San Francisco Bay

    USGS Publications Warehouse

    Dunlap, C.E.; Bouse, R.; Flegal, A.R.

    2000-01-01

    Variations in the isotopic composition of lead in 1995-1998 river waters flowing into San Francisco Bay trace the washout of lead deposited in the drainage basin from leaded gasoline combustion. At the confluence of the Sacramento and San Joaquin rivers where they enter the Bay, the isotopic compositions of lead in the waters define a linear trend away from the measured historical compositions of leaded gas in California. The river waters are shifted away from leaded gasoline values and toward an isotopic composition similar to Sierra Nevadan inputs which became the predominant source of sedimentation in San Francisco Bay following the onset of hydraulic gold mining in 1853. Using lead isotopic compositions of hydraulic mine sediments and average leaded gasoline as mixing end members, we calculate that more than 50% of the lead in the present river water originated from leaded gasoline combustion. The strong adsorption of lead (log K(d) > 7.4) to particulates appears to limit the flushing of gasoline lead from the drainage basin, and the removal of that lead from the system may have reached an asymptotic limit. Consequently, gasoline lead isotopes should prove to be a useful nonpoint source tracer of the environmental distribution of particle- reactive anthropogenic metals in freshwater systems.

  7. Use of stable lead isotopes to characterize the sources of anthropogenic lead in North Atlantic surface waters

    SciTech Connect

    Veron, A.J. Univ. of Delaware, Newark, DE ); Church, T.M. ); Patterson, C.C. ); Flegal, A.R. Univ. of California, Santa Cruz, CA )

    1994-08-01

    Stable lead isotopes are used to illustrate the impact of surface water circulation on dissolved lead distribution in North Atlantic surface waters during oligotrophic conditions. Using stable lead isotopic signatures from (1) the Sargasso Sea and (2) direct tropospheric deposition to the North Atlantic, the authors estimate that 10-40% of the lead accumulated in surface waters of the European Basin is transported from the western North Atlantic by the North Atlantic Current. South of 50[degrees]N, lead appears to be primarily distributed by the Subtropical North Atlantic Gyre that extends well beyond the western basins to 30[degrees]W in the North African Basin (at 30-40[degrees]N). There are different lead isotopic signatures between the subtropical gyre of the Guiana and western Guinea Basins, which suggests that the Inter Tropical Convergence Zone acts as an efficient barrier limiting chemical exchanges between the gyre and the equatorial currents.

  8. Relative contribution of lead from anthropogenic sources to the total human lead exposure in the United States. Final report

    SciTech Connect

    Elias, R.W.

    1986-08-01

    The paper evaluates human exposure to lead at a baseline level for persons living in non-urban communities away from stationary or mobile sources of lead, eating typical diets, and engaging in no lead-related occupational or avocational activities. Relative contributions of atmospheric and metallic lead are evaluated for each exposure pathway. For this baseline situation, perhaps 40 to 55% of the total human exposure to lead is of atmospheric origin. Beyond the baseline level, additional exposure factors can be determined for other environments (e.g. urban, occupational, smelter communities) and for certain habits and activities (e.g., pica, smoking, drinking, and various hobbies), with variations for age, sex, or socioeconomic status. Although quantification of these factors is uncertain, they provide guidelines in determining relative exposures under differing environmental conditions. The added exposure factors can also be partitioned into atmospheric, metallic, and pigment lead.

  9. Natural background and anthropogenic inputs of polycyclic aromatic hydrocarbons (PAH) in sediments of South-Western Barents Sea.

    PubMed

    Boitsov, Stepan; Jensen, H K B; Klungsøyr, Jarle

    2009-12-01

    Polycyclic aromatic hydrocarbons (PAH) were measured in sediment cores from 13 locations in South-Western Barents Sea as part of a detailed study of the Norwegian seabed under the MAREANO program. The generally low PAH levels found, an average around 200 ng g(-1) dry weight for sum PAH, indicate low inputs of petroleum hydrocarbons to the marine environment in the area. Differences in PAH composition and various PAH ratios indicate a natural, mostly petrogenic origin of PAH in sediments from the open sea locations, while the fjord locations show higher pyrogenic PAH contents with an increase towards upper sediment layers, indicating low inputs from human activities. Petrogenic PAH levels increase in deeper sediments at open sea locations, also when normalised to total organic carbon (TOC) contents, suggesting natural leakages of oil-related hydrocarbons in the area.

  10. Monitoring of impact of anthropogenic inputs on water quality of mangrove ecosystem of Uran, Navi Mumbai, west coast of India.

    PubMed

    Pawar, Prabhakar R

    2013-10-15

    Surface water samples were collected from substations along Sheva creek and Dharamtar creek mangrove ecosystems of Uran (Raigad), Navi Mumbai, west coast of India. Water samples were collected fortnightly from April 2009 to March 2011 during spring low and high tides and were analyzed for pH, Temperature, Turbidity, Total solids (TS), Total dissolved solids (TDS), Total suspended solids (TSS), Dissolved oxygen (DO), Biochemical oxygen demand (BOD), Carbon dioxide (CO2), Chemical oxygen demand (COD), Salinity, Orthophosphate (O-PO4), Nitrite-nitrogen (NO2-N), Nitrate-nitrogen (NO3-N), and Silicates. Variables like pH, turbidity, TDS, salinity, DO, and BOD show seasonal variations. Higher content of O-PO4, NO3-N, and silicates is recorded due to discharge of domestic wastes and sewage, effluents from industries, oil tanking depots and also from maritime activities of Jawaharlal Nehru Port Trust (JNPT), hectic activities of Container Freight Stations (CFS), and other port wastes. This study reveals that water quality from mangrove ecosystems of Uran is deteriorating due to industrial pollution and that mangrove from Uran is facing the threat due to anthropogenic stress.

  11. Distribution and sources of pre-anthropogenic lead isotopes in deep ocean water from Fe-Mn crusts

    USGS Publications Warehouse

    Von Blanckenburg, F.; O'Nions, R. K.; Hein, J.R.

    1996-01-01

    The lead isotope composition of ocean water is not well constrained due to contamination by anthropogenic lead. Here the global distribution of lead isotopes in deep ocean water is presented as derived from dated (ca. 100 ka) surface layers of hydrogenetic Fe-Mn crusts. The results indicate that the radiogenic lead in North Atlantic deep water is probably supplied from the continents by river particulates, and that lead in Pacific deep water is similar to that characteristic of island and continental volcanic arcs. Despite a short residence time in deep water (80-100 a), the isotopes of lead appear to be exceedingly well mixed in the Pacific basin. There is no evidence for the import of North Atlantic deep water-derived lead into the Pacific ocean, nor into the North Indian Ocean. This implies that the short residence time of lead in deep water prohibits advection over such long distances. Consequently, any climate-induced changes in deep-water flow are not expected to result in major changes in the seawater Pb-isotope record of the Pacific Ocean.

  12. Reconstructing historical trends of Berre lagoon contamination from surface sediment datasets: influences of industrial regulations and anthropogenic silt inputs.

    PubMed

    Rigaud, S; Radakovitch, O; Nerini, D; Picon, P; Garnier, J M

    2011-09-01

    These last decades, the Berre lagoon (in southeastern France) has been deeply affected since the 1930s by strong inputs of contaminants associated with industrial development and since 1966 by huge inputs of freshwater and silts due to the installation of a hydroelectric power plant. Surveys of the surface sediment contamination have been sparsely performed since 1964 for management and research purposes. These surveys were performed by various laboratories that investigated different chemicals and sampling areas using different analysis protocols. Therefore, the available data are disconnected in time and space and differ in quality. In order to reconstruct coherent time series of sediment contamination from this heterogeneous datasets and to discuss the influences of industrial and hydroelectric discharges we used a statistical approach. This approach is based on Principal Component Analysis (PCA) and Fuzzy clustering analysis on data from one extensive survey realized on surface sediments in 1976. The PCA allowed identifying two geochemical indexes describing the main surface sediment geochemical characteristics. The fuzzy clustering analysis on these indexes allowed identifying sub-areas under the specific influence of industrial or hydroelectric discharges. This allowed us to reconstruct, for each sub-area, a coherent and interpretable long-term time series of sediment contamination from the available database. Reconstructed temporal trends allowed us to estimate: (i) the overall decrease of sediment contamination since the mid-1970 attributed to industrial discharge regulations enacted at this period and (ii) the dilution of the concentrations of sediment bound contaminants induced by the hydroelectric power plant and its associated particulate matter inputs. Copyright © 2011 Elsevier Ltd. All rights reserved.

  13. Persistent organic pollutants in coastal sediment off South China in relation to the importance of anthropogenic inputs.

    PubMed

    Liu, Liang-Ying; Wang, Ji-Zhong; Qiu, Jian-Wen; Liang, Yan; Zeng, Eddy Y

    2012-06-01

    Surface sediments collected from the coastal region off South China were analyzed for persistent organic pollutants (POPs), including polybrominated diphenyl ethers (PBDEs), polycyclic aromatic hydrocarbons (PAHs), and organochlorine pesticides (OCPs). The concentrations of BDE-209, Σ(12)PBDE, Σ(15)PAH, Σ(7)PAH, and Σ(11)OCP were 0.22 to 26.3, 0.01 to 0.77, 13.9 to 271, 6 to 133, and 0.9 to 104 ng/g, respectively. The spatial distribution patterns of PBDEs and PAHs suggested that the eastern coastal region was slightly more contaminated than the western coast. In addition, the concentrations of dichlorodiphenyltrichloroethane (DDT) and its metabolites (DDXs) were highly variable, with the highest level found at a site in Zhanjiang Bay, which might have been reflective of the impact of antifouling paints mainly used in boat maintenance in harbor areas. The predominance of BDE-209 in the study region was consistent with the usage pattern of penta-, octa-, and deca-BDEs in China, whereas sediment PAHs appeared to have been derived largely from coal or wood and petroleum combustion. Preliminary assessments indicated that terrestrial inputs, such as atmospheric transport and riverine runoff, may have been the major input pathways for PBDEs and PAHs, respectively, to accumulate in coastal sediment off South China. Conversely, residues of DDT-containing antifouling paints associated with shipping activities and boat maintenance accounted for most of the accumulated sediment DDTs.

  14. (210)Pb and composition data of near-surface sediments and interstitial waters evidencing anthropogenic inputs in Amazon River mouth, Macapá, Brazil.

    PubMed

    Nery, José Reinaldo Cardoso; Bonotto, Daniel Marcos

    2011-04-01

    Activity profiles of excess (210)Pb determined in three sediment cores from Amazon River mouth, Macapá city, Brazil, provided the evaluation of sedimentation rates, contributing to a better knowledge of the hydrological conditions in the site that is the capital of Amapá State and is drained by the waters of the huge Amazon River. Chemical data were also determined in the sediments, allowing identify signatures coupled to anthropogenic inputs held in the past in Amapá State. Significant direct relationships between LOI (loss on ignition) and organic matter were found for all sediments profiles. Silica was found to be inversely related to organic matter in the three profiles; its decrease accompanied an increase on the specific surface of the sediments. This relationship was confirmed by a great number of inverse significant correlations among silica and oxides Na(2)O, K(2)O, CaO, MgO, Al(2)O(3), P(2)O(5), Fe(2)O(3) and MnO. It was possible to identify the role of organic matter on adsorption of several oxides in the core sediments profiles. Apparent sediment mass accumulation rates corresponding to values between 450 and 2510 mg cm(-2)yr(-1) were obtained, and are compatible with the results of others studies. The (210)Pb activities in one sampling point suggested the occurrence of anthropogenic inputs related to the initial period of the mining activities conducted in Serra do Navio, Amapá State, for the commercialization of Mn ores. This was reinforced by the abrupt fluctuations in chemical data obtained for the sediments and composition of the interstitial waters occurring there. The Atlantic hurricane activity also appeared to affect the sedimentation rates in the area, as two different values were recorded in each profile. Copyright © 2011 Elsevier Ltd. All rights reserved.

  15. Anthropogenic effects on shoreface and shoreline changes: Input from a multi-method analysis, Agadir Bay, Morocco

    NASA Astrophysics Data System (ADS)

    Aouiche, Ismail; Daoudi, Lahcen; Anthony, Edward J.; Sedrati, Mouncef; Ziane, Elhassane; Harti, Abderrazak; Dussouillez, Philippe

    2016-02-01

    In many situations, the links between shoreline fluctuations and larger-scale coastal change embracing the shoreface are not always well understood. In particular, meso-scale (years to decades) sand exchanges between the shoreface and the shoreline, considered as important on many wave-dominated coasts, are rather poorly understood and difficult to identify. Coastal systems where sediment transport is perturbed by engineering interventions on the shoreline and shoreface commonly provide fine examples liable to throw light on these links. This is especially so where shoreface bathymetric datasets, which are generally lacking, are collected over time, enabling more or less fine resolution of the meso-scale coastal sediment budget. Agadir Bay and the city of Agadir together form one of the two most important economic development poles on the Atlantic coast of Morocco. Using a combined methodological approach based on wave-current modelling, bathymetric chart-differencing, determination of shoreline fluctuations, and beach topographic surveying, we highlight the close links between variations in the bed of the inner shoreface and the bay shoreline involving both cross-shore and longshore sand transport pathways, sediment budget variations and new sediment cell patterns. We show that the significant changes that have affected the bay shoreline and shoreface since 1978 clearly reflect anthropogenic impacts, notably blocking of alongshore sand transport by Agadir harbour, completed in 1988, and the foundations of which lie well beyond the depth of wave closure. Construction of the harbour has led to the creation of a rapidly accreting beach against an original portion of rocky shoreline updrift and to a net sand loss exceeding 145,000 m3/year between 1978 and 2012 over 8.5 km2of the bay shoreface downdrift. Shoreline retreat has been further exacerbated by sand extraction from aeolian dunes and by flattening of these dunes to make space for tourist infrastructure. Digital

  16. Immobilization of lead in anthropogenic contaminated soils using phosphates with/without oxalic acid.

    PubMed

    Su, Xiaojuan; Zhu, Jun; Fu, Qingling; Zuo, Jichao; Liu, Yonghong; Hu, Hongqing

    2015-02-01

    Understanding the effects of oxalic acid (OA) on the immobilization of Pb(II) in contaminated soils by phosphate materials, has considerable benefits for risk assessment and remediation strategies for the soil. A series of phosphate amendments with/without oxalic acid were applied to two anthropogenic contaminated soils. We investigated the immobilization of Pb(II) by KH2PO4, phosphate rock (PR), activated phosphate rock (APR) and synthetic hydroxyapatite (HAP) at different phosphate:Pb (P:Pb) molar ratios (0, 0.6, 2.0 and 4.0) in the presence/absence of 50 mmol oxalic acid/kg soil, respectively. The effects of treatments were evaluated using single extraction with deionized water or CaCl2, Community Bureau of Reference (BCR) sequential extraction and toxicity characteristic leaching procedure (TCLP) methods. Our results showed that the concentration of water extractable, exchangeable and TCLP-Pb all decreased with incubation time. The concentration of water-extractable Pb after 120 days was reduced by 100% when soils were amended with APR, HAP and HAP+OA, and the TCLP-Pb was <5 mg/L for the red soil at P:Pb molar ratio 4.0. Water-soluble Pb could not be detected and the TCLP-Pb was <5 mg/L at all treatments applied to the yellow-brown soil. BCR results indicated that APR was most effective, although a slight enhancement of water-soluble phosphate was detected at the P:Pb molar ratio 4.0 at the beginning of incubation. Oxalic acid activated phosphates, and so mixing insoluble phosphates with oxalic acid may be a useful strategy to improve their effectiveness in reducing Pb bioavailability. Copyright © 2014. Published by Elsevier B.V.

  17. Power and Limitations of Anhydrosugars to Trace Historical Natural and Anthropogenic Inputs of charcoal BC to Aquatic Systems

    NASA Astrophysics Data System (ADS)

    Louchouarn, P.; Kuo, L.; Brandenberger, J. M.; Andresen, C. S.; Kjaer, K. H.; Dalton, M.

    2011-12-01

    Plant-derived chars are the solid residues from incomplete combustion of plant materials. They are an important constituent in the black carbon (BC) continuum, an array of diverse pyrogenic organic materials ranging from slightly charred biomass (low temperature) to highly condensed refractory soot (high temperature). The characterization and quantification of plant-derived chars in environmental samples is a challenging process due to the heterogeneous nature of these substances. Most of the BC methods using oxidative approaches that seek to remove non-BC materials are limited in their potential to identify and quantify plant-derived chars because of their relative labilities compared to the condensed BC forms such as soot. Anhydrosugars, such as levoglucosan and its isomers (mannosan and galactosan), have generated considerable interest in recent years in BC research because they are exclusive thermal degradation products of cellulose/hemicellulose and are produced in different proportions in chars and smokes from low temperature combustion of different plant species permitting some source discrimination in environmental samples (e.g. softwoods vs. hardwoods; gymnosperms vs. angiosperms). We show here a synthesis of several years of work using levoglucosan in diverse environments to reconstruct local to large-scale environmental change from climate-driven wildfires to human and accidental fires. For example, in the Hood Canal (WA), the striking consistency between the fluxes of levoglucosan, the Pacific Decadal Oscillation (PDO) Index, and the Palmer Drought Severity Index (PDSI), suggests that climate oscillations may play a role in the historical wildfire activities and thus influence the inputs of char-BC to the Puget Sound. Similarly, peaks in anhydrosugars in a sediment core from Lake Copenhagen record large-scale accidental fires in the city of Copenhagen during the early and late 18th Century, and help constrain the geochronology of the core beyond the

  18. Synaptic Input Correlations Leading to Membrane Potential Decorrelation of Spontaneous Activity in Cortex

    PubMed Central

    Reyes, Alex D.

    2013-01-01

    Correlations in the spiking activity of neurons have been found in many regions of the cortex under multiple experimental conditions and are postulated to have important consequences for neural population coding. While there is a large body of extracellular data reporting correlations of various strengths, the subthreshold events underlying the origin and magnitude of signal-independent correlations (called noise or spike count correlations) are unknown. Here we investigate, using intracellular recordings, how synaptic input correlations from shared presynaptic neurons translate into membrane potential and spike-output correlations. Using a pharmacologically activated thalamocortical slice preparation, we perform simultaneous recordings from pairs of layer IV neurons in the auditory cortex of mice and measure synaptic potentials/currents, membrane potentials, and spiking outputs. We calculate cross-correlations between excitatory and inhibitory inputs to investigate correlations emerging from the network. We furthermore evaluate membrane potential correlations near resting potential to study how excitation and inhibition combine and affect spike-output correlations. We demonstrate directly that excitation is correlated with inhibition thereby partially canceling each other and resulting in weak membrane potential and spiking correlations between neurons. Our data suggest that cortical networks are set up to partially cancel correlations emerging from the connections between neurons. This active decorrelation is achieved because excitation and inhibition closely track each other. Our results suggest that the numerous shared presynaptic inputs do not automatically lead to increased spiking correlations. PMID:24048838

  19. Lead isotopes in North Pacific deep water - Implications for past changes in input sources and circulation patterns

    USGS Publications Warehouse

    van de Flierdt, T.; Frank, M.; Halliday, A.N.; Hein, J.R.; Hattendorf, B.; Gunther, D.; Kubik, P.W.

    2003-01-01

    The sources of non-anthropogenic Pb in seawater have been the subject of debate. Here we present Pb isotope time-series that indicate that the non-anthropogenic Pb budget of the northernmost Pacific Ocean has been governed by ocean circulation and riverine inputs, which in turn have ultimately been controlled by tectonic processes. Despite the fact that the investigated locations are situated within the Asian dust plume, and proximal to extensive arc volcanism, eolian contributions have had little impact. We have obtained the first high-resolution and high-precision Pb isotope time-series of North Pacific deep water from two ferromanganese crusts from the Gulf of Alaska in the NE Pacific Ocean, and from the Detroit Seamount in the NW Pacific Ocean. Both crusts were dated applying 10 Be/9Be ratios and yield continuous time-series for the past 13.5 and 9.6 Myr, respectively. Lead isotopes show a monotonic evolution in 206Pb/204Pb from low values in the Miocene (??? 18.57) to high values at present day (??? 18.84) in both crusts, even though they are separated by more than 3000 km along the Aleutian Arc. The variation exceeds the amplitude found in Equatorial Pacific deep water records by about three-fold. There also is a striking similarity in 207Pb/204Pb and 208Pb/ 204Pb ratios of the two crusts, indicating the existence of a local circulation cell in the sub-polar North Pacific, where efficient lateral mixing has taken place but only limited exchange (in terms of Pb) with deep water from the Equatorial Pacific has occurred. Both crusts display well-defined trends with age in Pb-Pb isotope mixing plots, which require the involvement of at least four distinct Pb sources for North Pacific deep water. The Pb isotope time-series reveal that eolian supplies (volcanic ash and continent-derived loess) have only been of minor importance for the dissolved Pb budget of marginal sites in the deep North Pacific over the past 6 Myr. The two predominant sources have been young

  20. Lead isotopes in North Pacific deep water - implications for past changes in input sources and circulation patterns

    NASA Astrophysics Data System (ADS)

    van de Flierdt, Tina; Frank, Martin; Halliday, Alex N.; Hein, James R.; Hattendorf, Bodo; Günther, Detlef; Kubik, Peter W.

    2003-04-01

    The sources of non-anthropogenic Pb in seawater have been the subject of debate. Here we present Pb isotope time-series that indicate that the non-anthropogenic Pb budget of the northernmost Pacific Ocean has been governed by ocean circulation and riverine inputs, which in turn have ultimately been controlled by tectonic processes. Despite the fact that the investigated locations are situated within the Asian dust plume, and proximal to extensive arc volcanism, eolian contributions have had little impact. We have obtained the first high-resolution and high-precision Pb isotope time-series of North Pacific deep water from two ferromanganese crusts from the Gulf of Alaska in the NE Pacific Ocean, and from the Detroit Seamount in the NW Pacific Ocean. Both crusts were dated applying 10Be/ 9Be ratios and yield continuous time-series for the past 13.5 and 9.6 Myr, respectively. Lead isotopes show a monotonic evolution in 206Pb/ 204Pb from low values in the Miocene (≤18.57) to high values at present day (≥18.84) in both crusts, even though they are separated by more than 3000 km along the Aleutian Arc. The variation exceeds the amplitude found in Equatorial Pacific deep water records by about three-fold. There also is a striking similarity in 207Pb/ 204Pb and 208Pb/ 204Pb ratios of the two crusts, indicating the existence of a local circulation cell in the sub-polar North Pacific, where efficient lateral mixing has taken place but only limited exchange (in terms of Pb) with deep water from the Equatorial Pacific has occurred. Both crusts display well-defined trends with age in Pb-Pb isotope mixing plots, which require the involvement of at least four distinct Pb sources for North Pacific deep water. The Pb isotope time-series reveal that eolian supplies (volcanic ash and continent-derived loess) have only been of minor importance for the dissolved Pb budget of marginal sites in the deep North Pacific over the past 6 Myr. The two predominant sources have been young

  1. Pyrogenic inputs of anthropogenic Pb and Hg to sediments of the Hood Canal, Washington, in the 20th century: source evidence from stable Pb isotopes and PAH signatures.

    PubMed

    Louchouarn, Patrick; Kuo, Li-Jung; Brandenberger, Jill M; Marcantonio, Franco; Garland, Charity; Gill, Gary A; Cullinan, Valerie

    2012-06-05

    Combustion-derived PAHs and stable Pb isotopic signatures ((206)Pb/(207)Pb) in sedimentary records assisted in reconstructing the sources of atmospheric inputs of anthropogenic Pb and Hg to the Hood Canal, Washington. The sediment-focusing corrected peak fluxes of total Pb and Hg (1960-70s) demonstrate that the watershed of Hood Canal has received greater atmospheric inputs of these metals than its mostly rural land use would predict. The tight relationships between the Pb, Hg, and organic markers in the cores indicate that these metals are derived from industrial combustion emissions. Multiple lines of evidence point to the Asarco smelter, located in the Main Basin of Puget Sound, as the major emission source of these metals to the watershed of the Hood Canal. The evidence includes (1) similar PAH isomer ratios in sediment cores from the two basins, (2) the correlations between Pb, Hg, and Cu in sediments and previously studied environmental samples including particulate matter emitted from the Asarco smelter's main stack at the peak of production, and (3) Pb isotope ratios. The natural rate of recovery in Hood Canal since the 1970s, back to preindustrial metal concentrations, was linear and contrasts with recovery rates reported for the Main Basin which slowed post late 1980s.

  2. The urban environmental gradient: Anthropogenic influences on the spatial and temporal distributions of lead and zinc in sediments

    SciTech Connect

    Callender, E.; Rice, K.C.

    2000-01-15

    Urban settings are a focal point for environmental contamination due to emissions from industrial and municipal activities and the widespread use of motor vehicles. As part of the National Water-Quality Assessment Program of the US Geological Survey, streamed-sediment and dated reservoir-sediment samples were collected from the Chattahoochee River Basin and analyzed for total lead (Pb) and zinc (Zn) concentrations. The sampling transect extends from northern Georgia, through Atlanta, to the Gulf of Mexico and reflects a steep gradient in population density from nearly 1,000 people/km{sup 2} in the Atlanta Metropolitan Area to fewer than 50 people/km{sup 2} in rural areas of southern Georgia and northern Florida. Correlations among population density, traffic density, and total and anthropogenic Pb and Zn concentrations indicate that population density is strongly related to traffic density and is a predictor o Pb and Zn concentrations in the environment derived from anthropogenic activities. Differences in the distributions of total Pb and Zn concentrations along the urban-suburban-rural gradient from Atlanta to the Florida Panhandle are related to temporal and spatial processes. That is, with the removal of leaded gasoline starting in the late 1970s, peak Pb concentrations have decreased to the present. Conversely, increased vehicular usage has kept Zn concentrations elevated in runoff from populated centers, which is reflected in the continued enrichment of Zn in aquatic sediments. Sediments from rural areas also contain elevated concentrations of Zn, possibly in response to substantial power plant emissions for the region, as well as vehicular traffic.

  3. The urban environmental gradient: Anthropogenic influences on the spatial and temporal distributions of lead and zinc in sediments

    USGS Publications Warehouse

    Callender, Edward; Rice, Karen C.

    2000-01-01

    Urban settings are a focal point for environmental contamination due to emissions from industrial and municipal activities and the widespread use of motor vehicles. As part of the National Water-Quality Assessment Program of the U.S. Geological Survey, streambed-sediment and dated reservoir-sediment samples were collected from the Chattahoochee River Basin and analyzed for total lead (Pb) and zinc (Zn) concentrations. The sampling transect extends from northern Georgia, through Atlanta, to the Gulf of Mexico and reflects a steep gradient in population density from nearly 1000 people/km2 in the Atlanta Metropolitan Area to fewer than 50 people/km2 in rural areas of southern Georgia and northern Florida. Correlations among population density, traffic density, and total and anthropogenic Pb and Zn concentrations indicate that population density is strongly related to traffic density and is a predictor of Pb and Zn concentrations in the environment derived from anthropogenic activities. Differences in the distributions of total Pb and Zn concentrations along the urban−suburban−rural gradient from Atlanta to the Florida Panhandle are related to temporal and spatial processes. That is, with the removal of leaded gasoline starting in the late 1970s, peak Pb concentrations have decreased to the present. Conversely, increased vehicular usage has kept Zn concentrations elevated in runoff from population centers, which is reflected in the continued enrichment of Zn in aquatic sediments. Sediments from rural areas also contain elevated concentrations of Zn, possibly in response to substantial power plant emissions for the region, as well as vehicular traffic.

  4. [Dynamic response of riverine nitrate flux to net anthropogenic nitrogen inputs in a typical river in Zhejiang Province over the 1980-2010 period].

    PubMed

    Zhang, Bai-Fa; Chen, Ding-Jiang

    2014-08-01

    Based on long-term records of river water quality and discharge and nitrogen sources as well as the LOADEST model, annual riverine NO3(-)-N flux and net anthropogenic nitrogen input (NANI) were both estimated for a typical river catchment (2 474 km2) in Zhejiang Province over the 1980-2010 period. Historical trends in both riverine NO3(-) -N flux and NANI and their dynamic relationships were then fully addressed. Finally, the contributions of annual NANI, retained nitrogen pools, and natural background sources to riverine NO3(-)-N flux were indentified. Results indicated that both riverine NO3(-) -N flux and NANI showed parabolic changing trends with peak value of 5.74 kg x (hm2 x a) for flux and 77.5 kg x (hm2 x a)(-1) for NANI both occurring around 1998. In 1980-2010, net increase of riverine NO3(-) -N flux and NANI was -42% and -77%, respectively. Chemical nitrogen fertilizer application and atmospheric nitrogen deposition, which accounted for -48% and -40% of NANI, respectively, were the major sources of NANI. Although interannual change of riverine NO3(-) -N flux was significantly related to NANI (R2 = 0. 27 * *) as well as the chemical nitrogen fertilizer application amount (R2 = 0.32 * *), it showed higher dependence on the river water discharge (R2 = 0.79 * *) or precipitation (R2 = 0.63 * *), implying that annual riverine NO3(-) -N was not only originated from current year's NANI, but also derived from retained N pools that were ultimately derived from NANI in previous years. A regression model developed by incorporating both NANI and water discharge could account for 94% of the variability of annual NO3(-) -N flux. This model predicted that NO3(-) -N flux could have been reduced by -21% and -30% if the annual NANI and water discharge had been cut by 30%, respectively. Annual NANI, retained nitrogen pools, and natural background sources contributed to -53%, -24%, and -23% of the riverine NO3(-) -N flux, respectively, suggesting that -77% of flux was

  5. Natural and anthropogenic lead in soils and vegetables around Guiyang city, southwest China: a Pb isotopic approach.

    PubMed

    Li, Fei-Li; Liu, Cong-Qiang; Yang, Yuan-Gen; Bi, Xiang-Yang; Liu, Tao-Ze; Zhao, Zhi-Qi

    2012-08-01

    Soils, vegetables and rainwaters from three vegetable production bases in the Guiyang area, southwest China, were analyzed for Pb concentrations and isotope compositions to trace its sources in the vegetables and soils. Lead isotopic compositions were not distinguishable between yellow soils and calcareous soils, but distinguishable among sampling sites. The highest (207)Pb/(206)Pb and (208)Pb/(206)Pb ratios were found for rainwaters (0.8547-0.8593 and 2.098-2.109, respectively), and the lowest for soils (0.7173-0.8246 and 1.766-2.048, respectively). The (207)Pb/(206)Pb and (208)Pb/(206)Pb ratios increased in vegetables in the order of rootsanthropogenic end members in the mixing model, it was estimated that atmospheric Pb contributed 30-77% to total Pb for vegetable roots, 43-71% for stems, 72-85% for leaves, and 90% for capsicum fruits, whereas 10-70% of Pb in all vegetable parts was derived from soils. This research supports that heavy metal contamination in vegetables can result mainly from atmospheric deposition, and Pb isotope technique is useful for tracing the sources of Pb contamination in vegetables. Copyright © 2012 Elsevier B.V. All rights reserved.

  6. Tracing Anthropogenic Salinity Inputs to the Semi-arid Rio Grande River: A Multi-isotope Tracer (U, S, B and Sr) Approach

    NASA Astrophysics Data System (ADS)

    Garcia, S.; Nyachoti, S. K.; Ma, L.; Szynkiewicz, A.; McIntosh, J. C.

    2015-12-01

    High salinity in the Rio Grande has led to severe reductions in crop productivity and accumulation of salts in soils. These pressing issues exist for other arid rivers worldwide. Salinity contributions to the Rio Grande have not been adequately quantified, especially from agriculture, urban activities, and geological sources. Here, we use major element concentrations and U, S, B, Sr isotopic signatures to fingerprint the salinity sources. Our study area focuses on a 200 km long stretch of the Rio Grande from Elephant Butte Reservoir, NM to El Paso, TX. River samples were collected monthly from 2014 to 2015. Irrigation drains, groundwater wells, city drains and wastewater effluents were sampled as possible anthropogenic salinity end-members. Major element chemistry, U, S and Sr isotope ratios in the Rio Grande waters suggest multiple salinity inputs from geological, agricultural, and urban sources. Natural upwelling of groundwater is significant for the Rio Grande near Elephant Butte, as suggested by high TDS values and high (234U/238U), 87Sr/86Sr, δ34S ratios. Agricultural activities (e.g. flood irrigation, groundwater pumping, fertilizer use) are extensive in the Mesilla Valley. Rio Grande waters from this region have characteristic lower (234U/238U), 87Sr/86Sr, and δ34S ratios, with possible agricultural sources from use of fertilizers and gypsum. Agricultural practices during flood irrigation also intensify evaporation of Rio Grande surface water and considerably increase water salinity. Shallow groundwater signatures were also identified at several river locations, possibly due to the artificial pumping of local groundwater for irrigation. Impacts of urban activities to river chemistry (high NO3 and B concentrations) were evident for locations downstream to Las Cruces and El Paso wastewater treatment plants, supporting the use of the B isotope as an urban salinity tracer. This study improves our understanding of human impacts on water quality and elemental

  7. Does a more skilful meteorological input lead to a more skilful flood forecast at seasonal timescales?

    NASA Astrophysics Data System (ADS)

    Neumann, Jessica; Arnal, Louise; Magnusson, Linus; Cloke, Hannah

    2017-04-01

    Seasonal river flow forecasts are important for many aspects of the water sector including flood forecasting, water supply, hydropower generation and navigation. In addition to short term predictions, seasonal forecasts have the potential to realise higher benefits through more optimal and consistent decisions. Their operational use however, remains a challenge due to uncertainties posed by the initial hydrologic conditions (e.g. soil moisture, groundwater levels) and seasonal climate forcings (mainly forecasts of precipitation and temperature), leading to a decrease in skill with increasing lead times. Here we present a stakeholder-led case study for the Thames catchment (UK), currently being undertaken as part of the H2020 IMPREX project. The winter of 2013-14 was the wettest on record in the UK; driven by 12 major Atlantic depressions, the Thames catchment was subject to compound (concurrent) flooding from fluvial and groundwater sources. Focusing on the 2013-14 floods, this study aims to see whether increased skill in meteorological input translates through to more accurate forecasting of compound flood events at seasonal timescales in the Thames catchment. An earlier analysis of the ECMWF System 4 (S4) seasonal meteorological forecasts revealed that it did not skilfully forecast the extreme event of winter 2013-14. This motivated the implementation of an atmospheric experiment by the ECMWF to force the S4 to more accurately represent the low-pressure weather conditions prevailing in winter 2013-14 [1]. Here, we used both the standard and the "improved" S4 seasonal meteorological forecasts to force the EFAS (European Flood Awareness System) LISFLOOD hydrological model. Both hydrological forecasts were started on the 1st of November 2013 and run for 4 months of lead time to capture the peak of the 2013-14 flood event. Comparing the seasonal hydrological forecasts produced with both meteorological forcing data will enable us to assess how the improved meteorology

  8. Learning structure of sensory inputs with synaptic plasticity leads to interference

    PubMed Central

    Chrol-Cannon, Joseph; Jin, Yaochu

    2015-01-01

    Synaptic plasticity is often explored as a form of unsupervised adaptation in cortical microcircuits to learn the structure of complex sensory inputs and thereby improve performance of classification and prediction. The question of whether the specific structure of the input patterns is encoded in the structure of neural networks has been largely neglected. Existing studies that have analyzed input-specific structural adaptation have used simplified, synthetic inputs in contrast to complex and noisy patterns found in real-world sensory data. In this work, input-specific structural changes are analyzed for three empirically derived models of plasticity applied to three temporal sensory classification tasks that include complex, real-world visual and auditory data. Two forms of spike-timing dependent plasticity (STDP) and the Bienenstock-Cooper-Munro (BCM) plasticity rule are used to adapt the recurrent network structure during the training process before performance is tested on the pattern recognition tasks. It is shown that synaptic adaptation is highly sensitive to specific classes of input pattern. However, plasticity does not improve the performance on sensory pattern recognition tasks, partly due to synaptic interference between consecutively presented input samples. The changes in synaptic strength produced by one stimulus are reversed by the presentation of another, thus largely preventing input-specific synaptic changes from being retained in the structure of the network. To solve the problem of interference, we suggest that models of plasticity be extended to restrict neural activity and synaptic modification to a subset of the neural circuit, which is increasingly found to be the case in experimental neuroscience. PMID:26300769

  9. Preliminary Study of Lead-Oxide Cooled Fast Reactor with Natural Uranium as an Input Fuel with Reactor Shuffling Strategy

    NASA Astrophysics Data System (ADS)

    Mahmudah, Rida SN; Su'ud, Zaki

    2017-01-01

    A preliminary study of lead-oxide cooled fast reactor with natural uranium as an input fuel using reactor shuffling strategy has been conducted. In this study, reactor core is divided into four zone with the same volume, each zone use different uranium enrichment. The enrichment number is estimated so that in the end of reactor’s operation, we only need to add natural uranium as the fresh input fuel. This study used UN-PuN as the fuel and lead oxide as the coolant. Several parameter studies have been conducted to determine the most suitable input condition. It is confirmed in this study that with fuel : cladding : coolant ratio of 53 : 10 : 37, and uranium enrichment in the first to the fourth zone of 0%, 6.25%, 7.5% and 8%, respectively, the reactor can operate as long as 20 years of operation with terminal k-eff of 1.0004.

  10. Neonatal Restriction of Tactile Inputs Leads to Long-Lasting Impairments of Cross-Modal Processing

    PubMed Central

    Röder, Brigitte; Hanganu-Opatz, Ileana L.

    2015-01-01

    Optimal behavior relies on the combination of inputs from multiple senses through complex interactions within neocortical networks. The ontogeny of this multisensory interplay is still unknown. Here, we identify critical factors that control the development of visual-tactile processing by combining in vivo electrophysiology with anatomical/functional assessment of cortico-cortical communication and behavioral investigation of pigmented rats. We demonstrate that the transient reduction of unimodal (tactile) inputs during a short period of neonatal development prior to the first cross-modal experience affects feed-forward subcortico-cortical interactions by attenuating the cross-modal enhancement of evoked responses in the adult primary somatosensory cortex. Moreover, the neonatal manipulation alters cortico-cortical interactions by decreasing the cross-modal synchrony and directionality in line with the sparsification of direct projections between primary somatosensory and visual cortices. At the behavioral level, these functional and structural deficits resulted in lower cross-modal matching abilities. Thus, neonatal unimodal experience during defined developmental stages is necessary for setting up the neuronal networks of multisensory processing. PMID:26600123

  11. Simultaneous Measurements of Ossicular Velocity and Intracochlear Pressure Leading to the Cochlear Input Impedance in Gerbil

    PubMed Central

    Decraemer, W. F.; Khanna, S. M.; Olson, E. S.

    2008-01-01

    Recent measurements of three-dimensional stapes motion in gerbil indicated that the piston component of stapes motion was the primary contributor to intracochlear pressure. In order to make a detailed correlation between stapes piston motion and intracochlear pressure behind the stapes, simultaneous pressure and motion measurements were undertaken. We found that the scala vestibuli pressure followed the piston component of the stapes velocity with high fidelity, reinforcing our previous finding that the piston motion of the stapes was the main stimulus to the cochlea. The present data allowed us to calculate cochlear input impedance and power flow into the cochlea. Both the amplitude and phase of the impedance were quite flat with frequency from 3 kHz to at least 30 kHz, with a phase that was primarily resistive. With constant stimulus pressure in the ear canal the intracochlear pressure at the stapes has been previously shown to be approximately flat with frequency through a wide range, and coupling that result with the present findings indicates that the power that flows into the cochlea is quite flat from about 3 to 30 kHz. The observed wide-band intracochlear pressure and power flow are consistent with the wide-band audiogram of the gerbil. PMID:18459001

  12. The transfer of bomb radiocarbon and anthropogenic lead to the deep North Atlantic Ocean observed from a deep sea coral

    NASA Astrophysics Data System (ADS)

    Lee, Jong-Mi; Eltgroth, Selene F.; Boyle, Edward A.; Adkins, Jess F.

    2017-01-01

    Deep-ocean, Δ14C, Pb concentrations, and Pb isotopes were reconstructed from a deep-sea coral Enallopsammia rostrata from 1410 m depth off of Bermuda. Our high-resolution time series is created from closely spaced radial cross sections, with samples taken from the center of concentric coral growth bands that we show to be the oldest portion of the section. Prebomb radiocarbon ages from the coral demonstrate that the vertical growth rate of the coral is linear, and the age of the coral is estimated to be 560-630 yr old based on the growth rate. Using this age model to reconstruct Δ14C in deep seawater, we first detect bomb radiocarbon at the coral growth site around 1980, and show that Δ14C increased from - 80 ± 1 ‰ (average 1930-1979) to a plateau at - 39 ± 3 ‰ (1999-2001). Pb/Ca of the coral ranges between 1.1-4.5 nmol/mol during the 16th and 17th centuries, and Pb isotope ratios (206Pb/207Pb = 1.21, 208Pb/207Pb = 2.495) in this period agree with pre-anthropogenic values found in the pelagic sediments of the North Atlantic Ocean basin. Coral Pb/Ca is slightly elevated to 6.2 ± 0.9 nmol /mol between the 1740s and the 1850s and then increases to 25.1 ± 0.2 nmol /mol in the 1990s. The increase in coral Pb/Ca is accompanied by a decrease in coral 206Pb/207Pb and 208Pb/207Pb, indicating that the increase was caused by the infiltration of anthropogenic Pb to the coral growth site. Comparing our data to the surface coral Δ14C and Pb records from Bermuda reveals a time scale of tracer transport from the surface ocean to the coral growth site. Some characteristic features, e.g., the bomb-derived Δ14C increase, appear in the deep ocean approximately 25 yr later than the surface, but the overall increase of Δ14C and Pb in the deep ocean is smaller and slower than the surface, showing the importance of mixing during the transport of these tracers.

  13. Movement responses of caribou to human-induced habitat edges lead to their aggregation near anthropogenic features.

    PubMed

    Fortin, Daniel; Buono, Pietro-Luciano; Fortin, André; Courbin, Nicolas; Tye Gingras, Christian; Moorcroft, Paul R; Courtois, Réhaume; Dussault, Claude

    2013-06-01

    The assessment of disturbance effects on wildlife and resulting mitigation efforts are founded on edge-effect theory. According to the classical view, the abundance of animals affected by human disturbance should increase monotonically with distance from disturbed areas to reach a maximum at remote locations. Here we show that distance-dependent movement taxis can skew abundance distributions toward disturbed areas. We develop an advection-diffusion model based on basic movement behavior commonly observed in animal populations and parameterize the model from observations on radio-collared caribou in a boreal ecosystem. The model predicts maximum abundance at 3.7 km from cutovers and roads. Consistently, aerial surveys conducted over 161,920 km(2) showed that the relative probability of caribou occurrence displays nonmonotonic changes with the distance to anthropogenic features, with a peak occurring at 4.5 km away from these features. This aggregation near disturbed areas thus provides the predators of this top-down-controlled, threatened herbivore species with specific locations to concentrate their search. The edge-effect theory developed here thus predicts that human activities should alter animal distribution and food web properties differently than anticipated from the current paradigm. Consideration of such nonmonotonic response to habitat edges may become essential to successful wildlife conservation.

  14. Decrease of Zn, Cd and Pb concentrations in marine fish species over a decade as response to reduction of anthropogenic inputs: the example of Tagus estuary.

    PubMed

    Raimundo, Joana; Pereira, Patrícia; Caetano, Miguel; Cabrita, Maria Teresa; Vale, Carlos

    2011-12-01

    Concentrations of Zn, Cd and Pb were measured in muscle of pelagic, demersal and benthic fishes, captured in the coastal area adjoining the Tagus estuary (Portugal), in 1998 and 2010. Additionally, Pb and Cd were determined in estuarine waters, showing a pronounced decrease between 1999 and 2010. Accordingly, specimens captured in 2010 presented significantly lower metal concentrations than individuals caught in 1998. Reductions were more evident for Pb (reduction of 59-99%) than for Cd (14-93%) and Zn (17-54%). Values in pelagic and demersal species exhibited higher reductions than in benthic species. Decrease of metal concentrations in fish appears thus to reflect the improvement of estuarine water quality as anthropogenic sources have been reduced or eliminated. Furthermore, it emphasises the usefulness of the descriptor "Contaminants in Fish" to assess the efficiency of measures to achieve a good environmental status, in the scope of the Marine Strategy Framework Directive. Copyright © 2011 Elsevier Ltd. All rights reserved.

  15. A century long sedimentary record of anthropogenic lead (Pb), Pb isotopes and other trace metals in Singapore.

    PubMed

    Chen, Mengli; Boyle, Edward A; Switzer, Adam D; Gouramanis, Chris

    2016-06-01

    Reconstructing the history of metal deposition in Singapore lake sediments contributes to understanding the anthropogenic and natural metal deposition in the data-sparse Southeast Asia. To this end, we present a sedimentary record of Pb, Pb isotopes and eleven other metals (Ag, As, Ba, Cd, Co, Cr, Cu, Ni, Tl, U and Zn) from a well-dated sediment core collected near the depocenter of MacRitchie Reservoir in central Singapore. Before the 1900s, the sedimentary Pb concentration was less than 2 mg/kg for both soil and sediment, with a corresponding (206)Pb/(207)Pb of ∼1.20. The Pb concentration increased to 55 mg/kg in the 1990s, and correspondingly the (206)Pb/(207)Pb decreased to less than 1.14. The (206)Pb/(207)Pb in the core top sediment is concordant with the (206)Pb/(207)Pb signal of aerosols in Singapore and other Southeast Asian cities, suggesting that Pb in the reservoir sediment was mainly from atmospheric deposition. Using the Pb concentration in the topmost layer of sediment, the estimated atmospheric Pb flux in Singapore today is ∼1.6 × 10(-2) g/m(2) yr. The concentrations of eleven other metals preserved in the sediment were also determined. A principal component analysis showed that most of the metals exhibit an increasing trend towards 1990s with a local concentration peak in the mid-20(th) century. Copyright © 2016. Published by Elsevier Ltd.

  16. Determination of the provenance of cocoa by soil protolith ages and assessment of anthropogenic lead contamination by pb/nd and lead isotope ratios.

    PubMed

    Manton, William I

    2010-01-27

    The Pb contents of chocolate and the products it flavors are among the highest of all commonly consumed substances. Others have shown that this Pb is acquired by cocoa beans after harvesting and is concentrated in their shells, portions of which are ground up with the cotyledons during processing. It is shown here that the shells also contain the lanthanides Nd and Sm, which they appear to take up more slowly than Pb when dried on bare soil. Consideration of Pb/Nd ratios, model Sm-Nd ages and the isotope ratios of Pb and Sr indicates that, in the absence of contamination, the relationship between Pb and Nd in shells is y = 13.1x(-0.383), where x is the Nd concentration in microg/kg and y is the Pb/Nd ratio. For cocoa powders, the relationship is y = 114x(-0.988). Samples that plot above these curves are probably contaminated. Model ages indicate where the cocoa of cocoa powders is grown, and these same considerations point to African samples being uncontaminated but samples from Asia containing 50% anthropogenic Pb of Australian origin. No measurable Pb contamination occurs during the transport of beans and the manufacture of chocolate.

  17. Sensitivity of Global Modeling Initiative chemistry and transport model simulations of radon-222 and lead-210 to input meteorological data

    NASA Astrophysics Data System (ADS)

    Considine, D. B.; Bergmann, D. J.; Liu, H.

    2005-07-01

    We have used the Global Modeling Initiative chemistry and transport model to simulate the radionuclides radon-222 and lead-210 using three different sets of input meteorological information: 1. Output from the Goddard Space Flight Center Global Modeling and Assimilation Office GEOS-STRAT assimilation; 2. Output from the Goddard Institute for Space Studies GISS II' general circulation model; and 3. Output from the National Center for Atmospheric Research MACCM3 general circulation model. We intercompare these simulations with observations to determine the variability resulting from the different meteorological data used to drive the model, and to assess the agreement of the simulations with observations at the surface and in the upper troposphere/lower stratosphere region. The observational datasets we use are primarily climatologies developed from multiple years of observations. In the upper troposphere/lower stratosphere region, climatological distributions of lead-210 were constructed from ~25 years of aircraft and balloon observations compiled into the US Environmental Measurements Laboratory RANDAB database. Taken as a whole, no simulation stands out as superior to the others. However, the simulation driven by the NCAR MACCM3 meteorological data compares better with lead-210 observations in the upper troposphere/lower stratosphere region. Comparisons of simulations made with and without convection show that the role played by convective transport and scavenging in the three simulations differs substantially. These differences may have implications for evaluation of the importance of very short-lived halogen-containing species on stratospheric halogen budgets.

  18. Sensitivity of Global Modeling Initiative chemistry and transport model simulations of radon-222 and lead-210 to input meteorological data

    NASA Astrophysics Data System (ADS)

    Considine, D. B.; Bergmann, D. J.; Liu, H.

    2005-12-01

    We have used the Global Modeling Initiative chemistry and transport model to simulate the radionuclides radon-222 and lead-210 using three different sets of input meteorological information: 1. Output from the Goddard Space Flight Center Global Modeling and Assimilation Office GEOS-STRAT assimilation; 2. Output from the Goddard Institute for Space Studies GISS II' general circulation model; and 3. Output from the National Center for Atmospheric Research MACCM3 general circulation model. We intercompare these simulations with observations to determine the variability resulting from the different meteorological data used to drive the model, and to assess the agreement of the simulations with observations at the surface and in the upper troposphere/lower stratosphere region. The observational datasets we use are primarily climatologies developed from multiple years of observations. In the upper troposphere/lower stratosphere region, climatological distributions of lead-210 were constructed from ~25 years of aircraft and balloon observations compiled into the US Environmental Measurements Laboratory RANDAB database. Taken as a whole, no simulation stands out as superior to the others. However, the simulation driven by the NCAR MACCM3 meteorological data compares better with lead-210 observations in the upper troposphere/lower stratosphere region. Comparisons of simulations made with and without convection show that the role played by convective transport and scavenging in the three simulations differs substantially. These differences may have implications for evaluation of the importance of very short-lived halogen-containing species on stratospheric halogen budgets.

  19. Anthropogenic and natural lead isotopes in Fe-hydroxides and Fe-sulphates in a watershed associated with arsenic-enriched groundwater, Maine, USA

    USGS Publications Warehouse

    Ayuso, Robert A.; Foley, Nora K.

    2008-01-01

    A survey of the natural and anthropogenic sources of lead contributing to secondary minerals in sulphidic schists associated with arsenic-enriched groundwater in Coastal Maine shows that the most likely source is natural Pb, particularly from coexisting sulphide minerals. The secondary minerals also reflect notable contributions from anthropogenic Pb. The Pb isotopes establish pathways by which Pb, and by inference As, could have been transported from As-bearing minerals (arsenian pyrite, arsenopyrite, lollingite, orpiment, arsenic oxide and others), via sulphide oxidation or carbonation reactions into multiple generations of secondary minerals (goethite, hematite, jarosite, natrojarosite and others). Lead isotopic compositions of the sulphides and secondary minerals determined by thermal ionization mass spectrometry (n=53) range widely. Lead and As contents of the sulphides and secondary minerals overlap, and are generally positively correlated. Pyrite, the dominant sulphide in sulphidic schists associated with As-enriched groundwater in Coastal Maine, has values of 206Pb/204Pb from 18.186 to 18.391, 207Pb/204Pb from 15.617 to 15.657, 208Pb/204Pb from 38.052 to 38.210, 206Pb/207Pb from c. 1.1625 to 1.1760 and 208Pb/207Pb from c. 2.4276 to 2.4394. Mixtures of Fe-hydroxide and oxide minerals (predominantly goethite and hematite) and secondary Fe-sulphate minerals (jarosite, natrojarosite, rozenite and melanterite) in the sulphidic schists have overlapping but generally higher values of 206Pb/204Pb from 18.495 to 19.747 (one sample at 21.495), 207Pb/204Pb from 15.595 to 15.722 (one sample at 15.839), 208Pb/204Pb from 38.186 to 39.162,206Pb/207Pb from c.1.1860 to 1.2575 (one sample at 1.3855) and 208Pb/207Pb from c. 2.4441 to 2.4865 than the sulphides. Sulphides from Zn-Pb metal mines are somewhat less radiogenic than sulphides from the schists. Other sulphides (mostly pyrite) associated with pegmatites and granitic rocks are heterogeneous and more

  20. The circumvention of the natural biopurification of calcium along nutrient pathways by atmospheric inputs of industrial lead

    NASA Astrophysics Data System (ADS)

    Elias, Robert W.; Hirao, Yoshimitsu; Patterson, Clair C.

    1982-12-01

    Biopurification factors for Ca with respect to Sr, Ba, and natural, uncontaminated Pb were measured for different nutrient-consumer pairs in a remote subalpine ecosystem. The factor for Sr is expressed as: (nutrient Sr/Ca) ÷ (consumer Sr/Ca). Similar expressions were used for Ba/Ca and Pb/Ca. It was found that Ca was biopurified of Sr 3-fold, of Ba 16-fold, and of Pb 100-fold in going from rock to sedge leaves. In going from sedge leaf to vole, Ca was biopurified of Sr 4-fold, of Ba 8-fold, and of Pb 16-fold. In going from meadow vole to pine marten, Ca was biopurified of Sr 6-fold, of Ba 7-fold, and of Pb 1.1-fold. Similar ranges of values for these factors were obtained for detrital and amphibian food chains. Fluxes of industrial lead entering the ecosystem as precipitation and dry deposition were measured and it was found that 40% of the lead in soil humus and soil moisture, 82% of the lead in sedge leaves, 92% of the lead in vole, and 97% of the lead in marten was industrial. The natural skeletal Pb/Ca ratio in carnivores (4 × 10 -8) was determined by means of corrections for inputs of industrial lead, food chain relationships, and measured biopurification factors for the ecosystem studied. This represents a 1700-fold reduction of the average Pb/Ca ratio in igneous rocks at the earth's surface (6.4 × 10 -5) by the compounding of successive Pb biopurification factors in transferring Ca from rock to carnivore. The natural ratio is similar to the value of 6 × 10 -8 observed for Pb/Ca in the bones of Peruvians who lived 2000 years ago but is 1/900th of the value of about 3.5 × 10 -5 for the skeletal Pb/Ca ratio found in present day Americans. This study shows experimentally how the Ba/Ca ratio in average surface igneous rock (3 × 10 -3) has been reduced 800-fold through compounding of successive biopurification steps to provide the skeletal Ba/Ca ratio of about 4 × 10 -6 observed in humans. It also provides biopurification factors for Sr and Ba among a

  1. Distribution, inventory and turnover of benthic organic biomass in the Strait of Georgia, Canada, in relation to natural and anthropogenic inputs.

    PubMed

    Burd, Brenda J

    2014-05-15

    Recently compiled databases facilitated estimation of basin-wide benthic organic biomass and turnover in the Strait of Georgia, an inland sea off western Canada. Basin-wide organic biomass was estimated at 43.1 × 10(6) kg C and production was 54.6 × 10(6) kg Cyr(-1), resulting in organic biomass turnover (P/B) of 1.27 × yr(-1). Organic biomass and production for sub-regions were predictable from modified organic flux (r(2)>0.9). P/B declined significantly with increasing modified organic flux, suggesting greater biomass storage in high flux sediments. Biomass and production were highest, and P/B lowest near the Fraser River. Annual basin-wide benthic production was 60% of previously estimated oxidized organic flux to substrates, which agrees with proportional measurements from a recent, localized study. Deviations from expected patterns related to organic enrichment and other stressors are discussed, as are potential impacts to benthic biomass and production, of declining bottom oxygen, increasing bottom temperature and potential changes in riverine input. Copyright © 2014 Elsevier Ltd. All rights reserved.

  2. δ(15)N variation in Ulva lactuca as a proxy for anthropogenic nitrogen inputs in coastal areas of Gulf of Gaeta (Mediterranean Sea).

    PubMed

    Orlandi, Lucia; Bentivoglio, Flavia; Carlino, Pasquale; Calizza, Edoardo; Rossi, David; Costantini, Maria Letizia; Rossi, Loreto

    2014-07-15

    We tested the capacity of Ulva lactuca to mark N sources across large marine areas by measuring variation in its δ(15)N at several sites in the Gulf of Gaeta. Comparisons were made with the macroalga Cystoseira amentacea. Variation of δ(15)N values was assessed also in the coastal waters off the Circeo Natural Park, where U. lactuca and C. amentacea were harvested, as these waters are barely influenced by human activities and were used as reference site. A small fragment from each frond was preserved before deployment in order to characterize the initial isotopic values. After 48 h of submersion, U. lactuca was more responsive than C. amentacea to environmental variation and δ(15)N enrichment in the Gulf of Gaeta was observed. The spatial distribution of δ(15)N enrichment indicated that different macro-areas in the Gulf were affected by N inputs from different origins. Comparison of the δ(15)N values of fragments taken from the same transplanted frond avoided bias arising from natural isotopic variability. Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.

  3. Precession driven changes in terrestrial organic matter input to the Eastern Mediterranean leading up to the Messinian Salinity Crisis

    NASA Astrophysics Data System (ADS)

    Mayser, Jan Peter; Flecker, Rachel; Marzocchi, Alice; Kouwenhoven, Tanja J.; Lunt, Dan J.; Pancost, Rich D.

    2017-03-01

    Eastern Mediterranean sediments over the past 12 Myr commonly show strongly developed precessional cyclicity, thought to be a biogeochemical response to insolation-driven freshwater input from run-off. The Mediterranean's dominant freshwater source today and in the past, is the Nile, which is fed by North African monsoon rain; other, smaller, circum-Mediterranean rivers also contribute to Mediterranean hydrology. Crucially, run-off through all of these systems appears to vary with precession, but there is no direct evidence linking individual water sources to the biogeochemical response recorded in Mediterranean sediments. Consequently, it is not clear whether the North African monsoon is entirely responsible for the Mediterranean's sedimentary cyclicity, or whether other, precessional signals, such as Atlantic storm precipitation, drive it. Organic matter in sediments derives from both marine and terrestrial sources and biomarker analysis can be used to discriminate between the two, thereby providing insight into sedimentary and ecological processes. We analysed a wide range of lipids from the Late Miocene (6.6-5.9 Ma) Pissouri section, southern Cyprus, and reconstructed the vegetation supplied to this region by measuring the carbon isotopes of the terrestrial component to identify its geographic source. BIT (Branched-Isoprenoidal-Tetraether) indices reflect changes in the relative abundance of marine vs terrestrial (soil) organic matter inputs, and with the exception of records from the last deglaciation, this work is the first application of the BIT approach to the reconstruction of orbital impacts on sedimentological processes. BIT indices show that the organic matter supplied to Cyprus changed over the course of each precession cycle and was dominantly terrestrial during insolation maxima when North African run-off was enhanced. The δ13C values from these intervals are compatible with tropical North African vegetation. However, the δ13C record indicates that

  4. A new approach for quantifying cumulative, anthropogenic, atmospheric lead deposition using peat cores from bogs: Pb in eight Swiss peat bog profiles.

    PubMed

    Shotyk, W; Blaser, P; Grünig, A; Cheburkin, A K

    2000-04-17

    Peat cores taken from eight Swiss peatlands were used to calculate inventories of anthropogenic Pb using either Sc or Zr to quantify Pb derived from rock weathering. The shapes of the Pb/Sc and Pb/Zr profiles suggest that Pb was supplied exclusively by atmospheric deposition at all sites. At one of the sites (Etang de la Gruère), anthropogenic Pb was calculated using both Sc and Zr as the conservative reference element. Lithogenic Pb determined using Sc was twice that obtained using Zr, possibly because Zr resides only in zircons which are dense compared to pyroxene and amphibole which are the main Sc-bearing phases in the earth's crust. However, the inventory of 'natural' Pb (supplied almost entirely by soil dust) is dwarfed by the anthropogenic inventory such that anthropogenic Pb calculated using Sc and Zr agree to within 5%. The total amount of anthropogenic Pb accumulated in the bogs was calculated by simply adding the mass of anthropogenic Pb for each peat slice over the length of each core. Cumulative, anthropogenic Pb calculated in this way ranged from 1.0 to 9.7 g/m2 and showed pronounced regional differences: the site south of the Alps (Gola di Lago in Canton Ticino) with direct exposure to the heavily industrialized region of northern Italy received nearly 10 times more anthropogenic Pb as the sites in more remote alpine regions (Schöpfenwaldmoor in Canton Berne, and Mauntschas in Canton Grisons). The approach used here to calculate cumulative, anthropogenic, atmospheric Pb (CAAPb) is simple and robust, independent of the chronology of Pb deposition, and makes no assumptions about the immobility of Pb within the peat profile. Given the worldwide distribution of peat bogs, it should be possible to undertake continental and global inventories of atmospheric metal deposition, for both the natural and anthropogenic components of most trace metals of environmental interest.

  5. Regulation leads to increases in riparian vegetation, but not direct allochthonous inputs, along the Colorado River in Grand Canyon, Arizona

    USGS Publications Warehouse

    Kennedy, T.A.; Ralston, B.E.

    2012-01-01

    Dams and associated river regulation have led to the expansion of riparian vegetation, especially nonnative species, along downstream ecosystems. Nonnative saltcedar is one of the dominant riparian plants along virtually every major river system in the arid western United States, but allochthonous inputs have never been quantified along a segment of a large river that is dominated by saltcedar. We developed a novel method for estimating direct allochthonous inputs along the 387km-long reach of the Colorado River downstream of Glen Canyon Dam that utilized a GIS vegetation map developed from aerial photographs, empirical and literature-derived litter production data for the dominant vegetation types, and virtual shorelines of annual peak discharge (566m 3s -1 stage elevation). Using this method, we estimate that direct allochthonous inputs from riparian vegetation for the entire reach studied total 186metric tonsyear -1, which represents mean inputs of 470gAFDMm -1year -1 of shoreline or 5.17gAFDMm -2year -1 of river surface. These values are comparable to allochthonous inputs for other large rivers and systems that also have sparse riparian vegetation. Nonnative saltcedar represents a significant component of annual allochthonous inputs (36% of total direct inputs) in the Colorado River. We also estimated direct allochthonous inputs for 46.8km of the Colorado River prior to closure of Glen Canyon Dam using a vegetation map that was developed from historical photographs. Regulation has led to significant increases in riparian vegetation (270-319% increase in cover, depending on stage elevation), but annual allochthonous inputs appear unaffected by regulation because of the lower flood peaks on the post-dam river. Published in 2010 by John Wiley & Sons, Ltd.

  6. Identification of anthropogenic and natural inputs of sulfate into a karstic coastal groundwater system in northeast China: evidence from major ions, δ13CDIC and δ34SSO4

    NASA Astrophysics Data System (ADS)

    Han, D.; Song, X.; Currell, M. J.

    2015-11-01

    The hydrogeochemical processes controlling groundwater evolution in the Daweijia area of Dalian, northeast China, were characterized using hydrochemistry and isotopes of carbon and sulfur (δ13CDIC and δ34SSO4). The aim was to distinguish anthropogenic impacts as distinct from natural processes, with a particular focus on sulfate, which is found at elevated levels (range: 54.4 to 368.8 mg L-1; mean: 174.4 mg L-1) in fresh and brackish groundwater. The current investigation reveals minor seawater intrusion impact (not exceeding 5 % of overall solute load), in contrast with extensive impacts observed in 1982 during the height of intensive abstraction. This indicates that measures to restrict groundwater abstraction have been effective. However, hydrochemical facies analysis shows that the groundwater remains in a state of ongoing hydrochemical evolution (towards Ca-Cl type water) and quality degradation (increasing nitrate and sulphate concentrations). The wide range of NO3 concentrations (74.7-579 mg L-1) in the Quaternary aquifer indicates considerable input of fertilizers and/or leakage from septic systems. Both δ13C (-14.5 to -5.9 ‰) and δ34SSO4 (+5.4-+13.1 ‰) values in groundwater show increasing trends along groundwater flow paths. While carbonate minerals may contribute to increasing δ13CDIC and δ34SSO4 values in deep karstic groundwater, high loads of agricultural fertilizers reaching the aquifer via irrigation return flow are likely the main source of the dissolved sulfate in Quaternary groundwater, as shown by distinctive isotopic ratios and a lack of evidence for other sources in the major ion chemistry. According to isotope mass balance calculations, the fertilizer contribution to overall sulfate has reached an average of 62.1 % in the Quaternary aquifer, which has a strong hydraulic connection to the underlying carbonate aquifer. The results point to an alarming level of impact from the local intensive agriculture on the groundwater system, a

  7. Impacts of Anthropogenic Emissions in the Southeastern U.S. on Heterogeneous Chemistry of Isoprene-Derived Epoxides Leading to Secondary Organic Aerosol Formation (Invited)

    NASA Astrophysics Data System (ADS)

    Surratt, J. D.; Pye, H.; Lin, Y.; Budisulistiorini, S.; Zhang, H.; Marth, W.; Cui, T.; Arashiro, M.; Chu, K.; Zhang, Z.; Sexton, K.; Piletic, I.; Xie, Y.; Capps, S. L.; Luecken, D.; Hutzell, W. T.; Jaoui, M.; Canagaratna, M. R.; Croteau, D.; Jayne, J. T.; Worsnop, D. R.; Offenberg, J.; Kleindienst, T. E.; Lewandowski, M.; Edney, E.; Pinder, R. W.; Bartolotti, L.; Gold, A.

    2013-12-01

    Isoprene is a major source of secondary organic aerosol (SOA); however, the exact manner in which it forms SOA remains unclear. Improving our fundamental understanding of isoprene-derived SOA is key to improving existing air quality models, especially in the southeastern U.S. where models currently underestimate observations. By combining organic synthesis, computational calculations, mass spectrometry, smog chamber studies, and field measurements, we show that reactive epoxides, which include methacrylic acid epoxide (MAE) and isomeric isoprene epoxydiols (IEPOX), produced from the photochemical oxidation of isoprene are key to SOA formation. Furthermore, anthropogenic pollutants (NOx and SO2) enhance isoprene-derived epoxides as an SOA source. In the laboratory, we find that the reactive uptake of synthetic IEPOX and MAE standards onto acidified sulfate aerosol yields known isoprene-derived SOA tracers (2-methlytetrols, 2-methylglyceric acid, C5-alkene triols, 3-methyltetrahydrofuran-3,4-diols, dimers and organosulfates) that we measure in fine aerosol collected from multiple sites across the southeastern U.S. using gas chromatography/mass spectrometry (GC/MS) and liquid chromatography coupled to diode array detection and electrospray ionization high-resolution quadrupole time-of-flight mass spectrometry (LC/DAD-ESI-QTOFMS). Notably, IEPOX- and MAE-derived SOA tracers account for ~19% of the organic aerosol mass in Yorkville, GA. Moreover, real-time continuous chemical measurements of fine aerosol made using an Aerodyne Aerosol Chemical Speciation Monitor (ACSM) during summer 2011 and summer 2013 in Atlanta, GA, and Look Rock, TN, respectively, resolved an IEPOX-oxygenated organic aerosol (IEPOX-OOA) factor when applying positive matrix factorization (PMF) to the organic mass spectral time series. In Atlanta, this factor is found to account for ~33% of the fine OA mass and is correlated with IEPOX-derived SOA tracers (r2 = 0.6), sulfate (r2 = 0.5), and to some

  8. Lead

    MedlinePlus

    ... EPA United States Environmental Protection Agency Search Search Lead Contact Us Share Lead Poisoning is Preventable If your home was built ... to protect people from harmful lead exposures. Less Lead in Drinking Water = Better Health Learn about the ...

  9. Identification of anthropogenic and natural inputs of sulfate into a karstic coastal groundwater system in northeast China: evidence from major ions, δ13CDIC and δ34SSO4

    NASA Astrophysics Data System (ADS)

    Han, Dongmei; Song, Xianfang; Currell, Matthew J.

    2016-05-01

    The hydrogeochemical processes controlling groundwater evolution in the Daweijia area of Dalian, northeast China, were characterised using hydrochemistry and isotopes of carbon and sulfur (δ13CDIC and δ34SSO4). The aim was to distinguish anthropogenic impacts as distinct from natural processes, with a particular focus on sulfate, which is found at elevated levels (range: 54.4 to 368.8 mg L-1; mean: 174.4 mg L-1) in fresh and brackish groundwater. The current investigation reveals minor seawater intrusion impact (not exceeding 5 % of the overall solute load), in contrast with extensive impacts observed in 1982 during the height of intensive abstraction. This indicates that measures to restrict groundwater abstraction have been effective. However, hydrochemical facies analysis shows that the groundwater remains in a state of ongoing hydrochemical evolution (towards Ca-Cl type water) and quality degradation (increasing nitrate and sulfate concentrations). The wide range of NO3 concentrations (74.7-579 mg L-1) in the Quaternary aquifer indicates considerable input of fertilisers and/or leakage from septic systems. Both δ13C (-14.5 to -5.9 permil) and δ34SSO4 (+5.4 to +13.1 permil) values in groundwater show increasing trends along groundwater flow paths. While carbonate minerals may contribute to increasing δ13CDIC and δ34SSO4 values in deep karstic groundwater, high loads of agricultural fertilisers reaching the aquifer via irrigation return flow are likely the main source of the dissolved sulfate in Quaternary groundwater, as shown by distinctive isotopic ratios and a lack of evidence for other sources in the major ion chemistry. According to isotope mass balance calculations, the fertiliser contribution to overall sulfate has reached an average of 62.1 % in the Quaternary aquifer, which has a strong hydraulic connection to the underlying carbonate aquifer. The results point to an alarming level of impact from the local intensive agriculture on the groundwater

  10. Geomorphology of anthropogenic landscapes

    NASA Astrophysics Data System (ADS)

    Sofia, Giulia; Tarolli, Paolo

    2015-04-01

    advantage of having a fast procedure that does not require the user input. A further analysis highlights that the procedure can correctly depict anthropogenic landscapes having a road network density greater than 0 km/ km2. The effects of such road network on surface processes could be material for future research, opening new questions about differences due to human or landscape forcing on Earth surface processes. References Sofia G., Marinello F, Tarolli P. 2014. A new landscape metric for the identification of terraced sites: the Slope Local Length of Auto-Correlation (SLLAC). ISPRS Journal of Photogrammetry and Remote Sensing, doi:10.1016/j.isprsjprs.2014.06.018

  11. Prenatal Testosterone Treatment Leads to Changes in the Morphology of KNDy Neurons, Their Inputs, and Projections to GnRH Cells in Female Sheep.

    PubMed

    Cernea, Maria; Padmanabhan, Vasantha; Goodman, Robert L; Coolen, Lique M; Lehman, Michael N

    2015-09-01

    Prenatal testosterone (T)-treated ewes display a constellation of reproductive defects that closely mirror those seen in PCOS women, including altered hormonal feedback control of GnRH. Kisspeptin/neurokinin B/dynorphin (KNDy) neurons of the arcuate nucleus (ARC) play a key role in steroid feedback control of GnRH secretion, and prenatal T treatment in sheep causes an imbalance of KNDy peptide expression within the ARC. In the present study, we tested the hypothesis that prenatal T exposure, in addition to altering KNDy peptides, leads to changes in the morphology and synaptic inputs of this population, kisspeptin cells of the preoptic area (POA), and GnRH cells. Prenatal T treatment significantly increased the size of KNDy cell somas, whereas POA kisspeptin, GnRH, agouti-related peptide, and proopiomelanocortin neurons were each unchanged in size. Prenatal T treatment also significantly reduced the total number of synaptic inputs onto KNDy neurons and POA kisspeptin neurons; for KNDy neurons, the decrease was partly due to a decrease in KNDy-KNDy synapses, whereas KNDy inputs to POA kisspeptin cells were unaltered. Finally, prenatal T reduced the total number of inputs to GnRH cells in both the POA and medial basal hypothalamus, and this change was in part due to a decreased number of inputs from KNDy neurons. The hypertrophy of KNDy cells in prenatal T sheep resembles that seen in ARC kisspeptin cells of postmenopausal women, and together with changes in their synaptic inputs and projections to GnRH neurons, may contribute to defects in steroidal control of GnRH observed in this animal model.

  12. Prenatal Testosterone Treatment Leads to Changes in the Morphology of KNDy Neurons, Their Inputs, and Projections to GnRH Cells in Female Sheep

    PubMed Central

    Cernea, Maria; Padmanabhan, Vasantha; Goodman, Robert L.; Coolen, Lique M.

    2015-01-01

    Prenatal testosterone (T)-treated ewes display a constellation of reproductive defects that closely mirror those seen in PCOS women, including altered hormonal feedback control of GnRH. Kisspeptin/neurokinin B/dynorphin (KNDy) neurons of the arcuate nucleus (ARC) play a key role in steroid feedback control of GnRH secretion, and prenatal T treatment in sheep causes an imbalance of KNDy peptide expression within the ARC. In the present study, we tested the hypothesis that prenatal T exposure, in addition to altering KNDy peptides, leads to changes in the morphology and synaptic inputs of this population, kisspeptin cells of the preoptic area (POA), and GnRH cells. Prenatal T treatment significantly increased the size of KNDy cell somas, whereas POA kisspeptin, GnRH, agouti-related peptide, and proopiomelanocortin neurons were each unchanged in size. Prenatal T treatment also significantly reduced the total number of synaptic inputs onto KNDy neurons and POA kisspeptin neurons; for KNDy neurons, the decrease was partly due to a decrease in KNDy-KNDy synapses, whereas KNDy inputs to POA kisspeptin cells were unaltered. Finally, prenatal T reduced the total number of inputs to GnRH cells in both the POA and medial basal hypothalamus, and this change was in part due to a decreased number of inputs from KNDy neurons. The hypertrophy of KNDy cells in prenatal T sheep resembles that seen in ARC kisspeptin cells of postmenopausal women, and together with changes in their synaptic inputs and projections to GnRH neurons, may contribute to defects in steroidal control of GnRH observed in this animal model. PMID:26061725

  13. Semantic control and modality: an input processing deficit in aphasia leading to deregulated semantic cognition in a single modality.

    PubMed

    Thompson, Hannah E; Jefferies, Elizabeth

    2013-08-01

    Research suggests that semantic memory deficits can occur in at least three ways. Patients can (1) show amodal degradation of concepts within the semantic store itself, such as in semantic dementia (SD), (2) have difficulty in controlling activation within the semantic system and accessing appropriate knowledge in line with current goals or context, as in semantic aphasia (SA) and (3) experience a semantic deficit in only one modality following degraded input from sensory cortex. Patients with SA show deficits of semantic control and access across word and picture tasks, consistent with the view that their problems arise from impaired modality-general control processes. However, there are a few reports in the literature of patients with semantic access problems restricted to auditory-verbal materials, who show decreasing ability to retrieve concepts from words when they are presented repeatedly with closely related distractors. These patients challenge the notion that semantic control processes are modality-general and suggest instead a separation of 'access' to auditory-verbal and non-verbal semantic systems. We had the rare opportunity to study such a case in detail. Our aims were to examine the effect of manipulations of control demands in auditory-verbal semantic, non-verbal semantic and non-semantic tasks, allowing us to assess whether such cases always show semantic control/access impairments that follow a modality-specific pattern, or whether there are alternative explanations. Our findings revealed: (1) deficits on executive tasks, unrelated to semantic demands, which were more evident in the auditory modality than the visual modality; (2) deficits in executively-demanding semantic tasks which were accentuated in the auditory-verbal domain compared with the visual modality, but still present on non-verbal tasks, and (3) a coupling between comprehension and executive control requirements, in that mild impairment on single word comprehension was greatly

  14. Lead

    MedlinePlus

    ... are approximately half a million U.S. children ages 1-5 with blood lead levels above 5 micrograms per deciliter (µg/dL), the reference level at which CDC recommends public health actions be initiated. No safe blood lead level in children has been ...

  15. Impacts of atmospheric anthropogenic nitrogen on the open ocean.

    PubMed

    Duce, R A; LaRoche, J; Altieri, K; Arrigo, K R; Baker, A R; Capone, D G; Cornell, S; Dentener, F; Galloway, J; Ganeshram, R S; Geider, R J; Jickells, T; Kuypers, M M; Langlois, R; Liss, P S; Liu, S M; Middelburg, J J; Moore, C M; Nickovic, S; Oschlies, A; Pedersen, T; Prospero, J; Schlitzer, R; Seitzinger, S; Sorensen, L L; Uematsu, M; Ulloa, O; Voss, M; Ward, B; Zamora, L

    2008-05-16

    Increasing quantities of atmospheric anthropogenic fixed nitrogen entering the open ocean could account for up to about a third of the ocean's external (nonrecycled) nitrogen supply and up to approximately 3% of the annual new marine biological production, approximately 0.3 petagram of carbon per year. This input could account for the production of up to approximately 1.6 teragrams of nitrous oxide (N2O) per year. Although approximately 10% of the ocean's drawdown of atmospheric anthropogenic carbon dioxide may result from this atmospheric nitrogen fertilization, leading to a decrease in radiative forcing, up to about two-thirds of this amount may be offset by the increase in N2O emissions. The effects of increasing atmospheric nitrogen deposition are expected to continue to grow in the future.

  16. A dynamic model for the global cycling of anthropogenic vanadium

    NASA Astrophysics Data System (ADS)

    Hope, Bruce K.

    2008-12-01

    Vanadium is a major trace metal in fossil fuels. Combustion of residual fuel oils and coal in industrialized economies is recognized as the major source of anthropogenic vanadium. A dynamic mass balance model assessed the influence of anthropogenic inputs on the global distribution and cycling of vanadium between 1700 and 2400 assuming different fossil fuel consumption and V production (mining) scenarios. Anthropogenic V sources were divided into fossil fuel combustion, industrial, and domestic (nonindustrial human activity). By 2050, inputs of anthropogenic V could comprise ≈75-85% of those to the atmosphere, ≈21-33% to ocean dissolved, ≈9-13% to ocean particulate, and ≈28-43% of inputs to land; with between ≈61-64% of all anthropogenic inputs attributable to fossil fuel combustion. Contributions from combustion and industrial sources, although dominant relative to contributions from domestic sources between 1900 and 2100, were estimated to peak between 2000 and 2050. Accumulation of anthropogenic V on land and in the ocean apparently occurs because natural removal processes are unable to cope with increasing amounts and rates of anthropogenic contributions. Impacts or hazards associated with anthropogenic inputs are unlikely to be discernible or significant on a global scale, but may be measurable and meaningful at smaller scales (coastal waters, continental shelves, and bays), in the locality of specific sources, or given an unfavorable exposure scenario.

  17. Past and Future of the Anthropogenic Biosphere

    NASA Astrophysics Data System (ADS)

    Ellis, E. C.

    2010-12-01

    Human populations and their use of land have now transformed most of the terrestrial biosphere into anthropogenic biomes (anthromes). As anthromes have emerged as the dominant global forms of ecological pattern and process, human interactions with terrestrial ecosystems have become a key earth system process, determining the structure and functioning of the biosphere. This presentation explores Ester Boserup’s land use intensification theories as models for understanding the emergence and dynamics of anthromes and their ecological processes, including their biogeochemistry and community structure, from the mostly wild biosphere of the Holocene to the primarily anthropogenic biosphere of the present and future. Existing global models and data for human population growth and land use over the Holocene differ in their portrayal of the global transition to a mostly anthropogenic biosphere. Yet there is little doubt that human populations have continued to grow over the long term and that anthromes have been increasingly important global ecological systems for millennia. This is conclusive evidence that human interactions with ecosystems can be sustained over the long-term, albeit under conditions that may no longer be realizable by either Earth or human systems. The classic Malthusian paradigm, in which human population growth outstrips natural resources leading to population collapse is unsupported by historical observations at global scale. Boserupian intensification is the better model, providing a robust theoretical foundation in which socio-ecological systems evolve as human populations increase, towards increasingly efficient use of limiting natural resources and enhanced production of anthropogenic ecological services such as food. This is not a story of technical advance, but rather of the forced adoption of ever more energy-intensive technical solutions in support of ever increasing population demands. And it does explain historical changes in the biosphere

  18. Bacterioplankton Dynamics within a Large Anthropogenically Impacted Urban Estuary

    PubMed Central

    Jeffries, Thomas C.; Schmitz Fontes, Maria L.; Harrison, Daniel P.; Van-Dongen-Vogels, Virginie; Eyre, Bradley D.; Ralph, Peter J.; Seymour, Justin R.

    2016-01-01

    The abundant and diverse microorganisms that inhabit aquatic systems are both determinants and indicators of aquatic health, providing essential ecosystem services such as nutrient cycling but also causing harmful blooms and disease in impacted habitats. Estuaries are among the most urbanized coastal ecosystems and as a consequence experience substantial environmental pressures, providing ideal systems to study the influence of anthropogenic inputs on microbial ecology. Here we use the highly urbanized Sydney Harbor, Australia, as a model system to investigate shifts in microbial community composition and function along natural and anthopogenic physicochemical gradients, driven by stormwater inflows, tidal flushing and the input of contaminants and both naturally and anthropogenically derived nutrients. Using a combination of amplicon sequencing of the 16S rRNA gene and shotgun metagenomics, we observed strong patterns in microbial biogeography across the estuary during two periods: one of high and another of low rainfall. These patterns were driven by shifts in nutrient concentration and dissolved oxygen leading to a partitioning of microbial community composition in different areas of the harbor with different nutrient regimes. Patterns in bacterial composition were related to shifts in the abundance of Rhodobacteraceae, Flavobacteriaceae, Microbacteriaceae, Halomonadaceae, Acidomicrobiales, and Synechococcus, coupled to an enrichment of total microbial metabolic pathways including phosphorus and nitrogen metabolism, sulfate reduction, virulence, and the degradation of hydrocarbons. Additionally, community beta-diversity was partitioned between the two sampling periods. This potentially reflected the influence of shifting allochtonous nutrient inputs on microbial communities and highlighted the temporally dynamic nature of the system. Combined, our results provide insights into the simultaneous influence of natural and anthropogenic drivers on the structure and

  19. Bacterioplankton Dynamics within a Large Anthropogenically Impacted Urban Estuary.

    PubMed

    Jeffries, Thomas C; Schmitz Fontes, Maria L; Harrison, Daniel P; Van-Dongen-Vogels, Virginie; Eyre, Bradley D; Ralph, Peter J; Seymour, Justin R

    2015-01-01

    The abundant and diverse microorganisms that inhabit aquatic systems are both determinants and indicators of aquatic health, providing essential ecosystem services such as nutrient cycling but also causing harmful blooms and disease in impacted habitats. Estuaries are among the most urbanized coastal ecosystems and as a consequence experience substantial environmental pressures, providing ideal systems to study the influence of anthropogenic inputs on microbial ecology. Here we use the highly urbanized Sydney Harbor, Australia, as a model system to investigate shifts in microbial community composition and function along natural and anthopogenic physicochemical gradients, driven by stormwater inflows, tidal flushing and the input of contaminants and both naturally and anthropogenically derived nutrients. Using a combination of amplicon sequencing of the 16S rRNA gene and shotgun metagenomics, we observed strong patterns in microbial biogeography across the estuary during two periods: one of high and another of low rainfall. These patterns were driven by shifts in nutrient concentration and dissolved oxygen leading to a partitioning of microbial community composition in different areas of the harbor with different nutrient regimes. Patterns in bacterial composition were related to shifts in the abundance of Rhodobacteraceae, Flavobacteriaceae, Microbacteriaceae, Halomonadaceae, Acidomicrobiales, and Synechococcus, coupled to an enrichment of total microbial metabolic pathways including phosphorus and nitrogen metabolism, sulfate reduction, virulence, and the degradation of hydrocarbons. Additionally, community beta-diversity was partitioned between the two sampling periods. This potentially reflected the influence of shifting allochtonous nutrient inputs on microbial communities and highlighted the temporally dynamic nature of the system. Combined, our results provide insights into the simultaneous influence of natural and anthropogenic drivers on the structure and

  20. Impacts of anthropogenic pressures on the water quality of the Gironde Estuary (SW France) from the Urban Agglomeration of Bordeaux: spatial characterization and inputs of trace metal elements (Ag, As, Cd, Cu, Pb and Zn)

    NASA Astrophysics Data System (ADS)

    Kessaci, Kahina; Coynel, Alexandra; Blanc, Gérard; Deycard, Victoria N.; Derriennic, Hervé; Schäfer, Jörg

    2014-05-01

    Recent European legislation (2000/60/CE) has listed eight trace metal elements as priority toxic substances for water quality. Urban metal inputs into hydrosystems are of increasing interest to both scientists and managers facing restrictive environmental protection policies, population increase and changing metal applications. The Gironde Estuary (SW France; 625 km2) is known for its metal/metalloid pollution originating from industrial (e.g. Cd, Zn, Cu, As, Ag, Hg) or agricultural sources (e.g. Cu) in the main fluvial tributaries (Garonne and Dordogne Rivers). However, little peer-reviewed scientific work has addressed the impact of urban sources on the Gironde Estuary, especially the Urban Agglomeration of Bordeaux (~1 million inhabitants) located on the downstream branch of the Garonne River. In this study, a snapshot sampling campaign was performed in 2011 for characterizing the spatial distribution of dissolved and particulate metal/metalloid (As, Ag, Cd, Pb, Zn, Cu) concentrations in three suburban watersheds: the Jalle of Blanquefort (330 km2), Eau Bourde (140 km2), and Peugue (112 km2). Furthermore, particulate metal Enrichment Factors (EF) were calculated using local geochemical background measured at the bottom of a sediment core (492 cm). Results indicated that metal concentrations displayed a high spatial variability depending on the suburban watershed and the studied element. Local concentrations anomalies were observed for: (i) As in the Eau Bourde River in dissolved (4.2 μg/l) and particulate phases (246 mg/kg; EF= 20) and attributed to a nearby industrial incinerator; (ii) Zn in the Peugue River with maximum dissolved and particulate concentrations of 87 μg/l and 1580 mg/kg (EF=17), respectively, probably due to urban habitation runoff; (iii) Ag in the Jalle of Blanquefort River with high dissolved (74 ng/l) and particulate concentrations (33.7 mg/kg; EF=117) due to industrial activities in the downstream part. Based on hydro

  1. Pb-Sr isotopic and geochemical constraints on sources and processes of lead contamination in well waters and soil from former fruit orchards, Pennsylvania, USA: A legacy of anthropogenic activities

    USGS Publications Warehouse

    Ayuso, Robert A.; Foley, Nora K.

    2016-01-01

    Isotopic discrimination can be an effective tool in establishing a direct link between sources of Pb contamination and the presence of anomalously high concentrations of Pb in waters, soils, and organisms. Residential wells supplying water containing up to 1600 ppb Pb to houses built on the former Mohr orchards commercial site, near Allentown, PA, were evaluated to discern anthropogenic from geogenic sources. Pb (n = 144) and Sr (n = 40) isotopic data and REE (n = 29) data were determined for waters from residential wells, test wells (drilled for this study), and surface waters from pond and creeks. Local soils, sediments, bedrock, Zn-Pb mineralization and coal were also analyzed (n = 94), together with locally used Pb-As pesticide (n = 5). Waters from residential and test wells show overlapping values of 206Pb/207Pb, 208Pb/207Pb and 87Sr/86Sr. Larger negative Ce anomalies (Ce/Ce*) distinguish residential wells from test wells. Results show that residential and test well waters, sediments from residential water filters in water tanks, and surface waters display broad linear trends in Pb isotope plots. Pb isotope data for soils, bedrock, and pesticides have contrasting ranges and overlapping trends. Contributions of Pb from soils to residential well waters are limited and implicated primarily in wells having shallow water-bearing zones and carrying high sediment contents. Pb isotope data for residential wells, test wells, and surface waters show substantial overlap with Pb data reflecting anthropogenic actions (e.g., burning fossil fuels, industrial and urban processing activities). Limited contributions of Pb from bedrock, soils, and pesticides are evident. High Pb concentrations in the residential waters are likely related to sediment build up in residential water tanks. Redox reactions, triggered by influx of groundwater via wells into the residential water systems and leading to subtle changes in pH, are implicated in precipitation of Fe oxyhydroxides

  2. Climate shocks: Natural and anthropogenic

    SciTech Connect

    Kondratyev, K.Ya.

    1988-01-01

    Much recent climate research has focused on the effects of CO{sub 2} and radiatively important trace species, volcanic eruptions, and nuclear exchanges on our future climate. These studies suggest that anthropogenic influence will alter our present climate. The reliability of the climate models are a subject of debate, yet valid information derived from climate models is critical for policy-makers and politicians to make decisions regarding energy use and development and defense strategies. K.Ya. Kondratyev, a leading Soviet climate scientist, addresses the role of the greenhouse effect, nuclear winter, and volcanic eruptions on our climate in a recently published book entitled Climate Shocks: Natural and Anthropogenic. The book provides a detailed survey of the literature on these fields, including the pertinent Soviet literature that is often not surveyed by Western scientists.

  3. Isotopic tracing of anthropogenic Pb inventories and sedimentary fluxes in the Gulf of Lions (NW Mediterranean sea)

    NASA Astrophysics Data System (ADS)

    Ferrand, Jean-Luc; Hamelin, Bruno; Monaco, André

    1999-01-01

    Lead stable isotopes have been analyzed in 24 box-cores (0-50 cm) from various transects across the Gulf of Lions. Lead concentrations (23-85 ppm) and isotopic signatures ( 206Pb/ 207Pb=1.174-1.188) in surficial sediments clearly show the impact of pollutant lead that constitutes 22-80% of the lead accumulated in the first centimeter of these cores. This anthropogenic input is clearly distinct from the natural detrital lead, which comes with more radiogenic signatures ( 206Pb/ 207Pb=1.195-1.233). This makes stable lead measurements a useful complement to 210Pb or other radioactive tracers in studies of sedimentology and hydrodynamics in coastal environments. Comparison of riverine and atmospheric deposition with lead accumulated in the sediment cores indicates that the Rhône particulate input dominates the lead inventories in the continental shelf sediments. The total pollutant lead accumulated in the Gulf of Lions for the past century amounts to 84,000±18,200 tons. The accumulation of pollutant lead in the surficial sediments is in excess of the riverine and tropospheric input estimated from the literature. This may result from overestimation of pollutant lead accumulation on the continental self, due to insufficient sampling in this region and/or from an additional input from boundary scavenging of lead advected by the Liguro-Provençal current over the shelf.

  4. Anthropogenic Space Weather

    NASA Astrophysics Data System (ADS)

    Gombosi, T. I.; Baker, D. N.; Balogh, A.; Erickson, P. J.; Huba, J. D.; Lanzerotti, L. J.

    2017-04-01

    Anthropogenic effects on the space environment started in the late 19th century and reached their peak in the 1960s when high-altitude nuclear explosions were carried out by the USA and the Soviet Union. These explosions created artificial radiation belts near Earth that resulted in major damages to several satellites. Another, unexpected impact of the high-altitude nuclear tests was the electromagnetic pulse (EMP) that can have devastating effects over a large geographic area (as large as the continental United States). Other anthropogenic impacts on the space environment include chemical release experiments, high-frequency wave heating of the ionosphere and the interaction of VLF waves with the radiation belts. This paper reviews the fundamental physical process behind these phenomena and discusses the observations of their impacts.

  5. Pollution of River Mahaweli and farmlands under irrigation by cadmium from agricultural inputs leading to a chronic renal failure epidemic among farmers in NCP, Sri Lanka.

    PubMed

    Bandara, J M R S; Wijewardena, H V P; Bandara, Y M A Y; Jayasooriya, R G P T; Rajapaksha, H

    2011-10-01

    the tributaries was +0.48. This indicated a major contribution by the cropping system in the upper catchment area of River Mahaweli to the eventual Cd pollution of river water. Low soil pH (4.5-5.2), higher organic matter content (2-3%), and 18-20 cmol/kg cation exchange capacity (CEC) in upcountry soil have a cumulative effect in the easy release of Cd from soil with the heavy surface runoff in the upcountry wet zone. In view of the existing water conveyance system from upcountry to reservoirs in North Central Province (NCP) through diversion of River Mahaweli, in addition to their own nonpoint pollution by triple superphosphate fertilizer (TSP), this demands a change in overall upper catchment management to minimize Cd pollution through agriculture inputs to prevent CRF due to elevated dietary cadmium among NCP farmers.

  6. GESAMP Working Group 38, The Atmospheric Input of Chemicals to the Ocean

    NASA Astrophysics Data System (ADS)

    Duce, Robert; Liss, Peter

    2014-05-01

    There is growing recognition of the impact of the atmospheric input of both natural and anthropogenic substances on ocean chemistry, biology, and biogeochemistry as well as climate. These inputs are closely related to a number of important global change issues. For example, the increasing input of anthropogenic nitrogen species from the atmosphere to much of the ocean may cause a low level fertilization that could result in an increase in marine 'new' productivity of up to ~3% and thus impact carbon drawdown from the atmosphere. Similarly, much of the oceanic iron, which is a limiting nutrient in significant areas of the ocean, originates from the atmospheric input of minerals as a result of the long-range transport of mineral dust from continental regions. The increased supply of soluble phosphorus from atmospheric anthropogenic sources (through large-scale use of fertilizers) may also have a significant impact on surface-ocean biogeochemistry, but estimates of any effects are highly uncertain. There have been few assessments of the atmospheric inputs of sulfur and nitrogen oxides to the ocean and their impact on the rates of ocean acidification. These inputs may be particularly critical in heavily trafficked shipping lanes and in ocean regions proximate to highly industrialized land areas. Other atmospheric substances may also have an impact on the ocean, in particular lead, cadmium, and POPs. To address these and related issues the United Nations Group of Experts on the Scientific Aspects of Marine Environmental Protection (GESAMP) initiated Working Group 38, The Atmospheric Input of Chemicals to the Ocean, in 2008. This Working Group has had four meetings. To date four peer reviewed papers have been produced from this effort, with a least eight others in the process of being written or published. This paper will discuss some of the results of the Working Group's deliberations and its plans for possible future work.

  7. Anthropogenic modification of the oceans.

    PubMed

    Tyrrell, Toby

    2011-03-13

    Human activities are altering the ocean in many different ways. The surface ocean is warming and, as a result, it is becoming more stratified and sea level is rising. There is no clear evidence yet of a slowing in ocean circulation, although this is predicted for the future. As anthropogenic CO(2) permeates into the ocean, it is making sea water more acidic, to the detriment of surface corals and probably many other calcifiers. Once acidification reaches the deep ocean, it will become more corrosive to CaCO(3), leading to a considerable reduction in the amount of CaCO(3) accumulating on the deep seafloor. There will be a several thousand-year-long interruption to CaCO(3) sedimentation at many points on the seafloor. A curious feedback in the ocean, carbonate compensation, makes it more likely that global warming and sea-level rise will continue for many millennia after CO(2) emissions cease.

  8. Properties of Miniature Cantilever-Type Ultrasonic Motor Using Lead-Free Array-Type Multilayer Piezoelectric Ceramics of (Sr,Ca)2NaNb5O15 under High Input Power

    NASA Astrophysics Data System (ADS)

    Doshida, Yutaka; Shimizu, Hiroyuki; Mizuno, Youich; Tamura, Hideki

    2012-07-01

    The properties of miniature cantilever-type ultrasonic motors using lead-free array-type multilayer piezoelectric ceramics of (Sr,Ca)2NaNb5O15 (SCNN) developed using the design rule were investigated under high input power by comparison with the high-power properties of SCNN ceramics. The frequency dependence of the revolution speed reflected the nonlinear behavior of SCNN ceramics with the hard-spring effect and showed a mirror-reversed image relative to that of the motor of Pb(Zr,Ti)O3 (PZT) ceramics. The output power increased linearly with increasing input power up to 110 mW without heat generation, and the driving properties were almost the same as the expectations under low input power. The output power density characteristics of the motors were high in comparison with those of the commercialized motors of PZT ceramics. It appeared that the motors have a high potential as an environmental friendly piezoelectric device with excellent properties, reflecting the high-power properties of SCNN ceramics.

  9. Anthropogenic climate change

    SciTech Connect

    Budyko, M.I.; Izreal, Yu.A.

    1991-01-01

    The climate modeling community would agree that the present generation of theoretical models cannot adequately answer important question about the climatic implications of increasing concentrations of CO[sub 2] and other greenhouse gases. Society, however, is presently deciding by its action, or inaction, the policies that will deal with the extent and results of our collective flatulence. In this situation, an engineering approach to estimating the developing pattern of anthropogenic climate change is appropriate. For example, Budyko has argued that, while scientists may have made great advances in modelling the flow around an airfoil, engineers make extensive use of empirical equations and measurements to design airplanes that fly. Budyko and Izreal have produced an encyclopedic treatise summarizing the results of Soviet researchers in applying empirical and semiempirical methods to estimating future climatic patterns, and some of their ensuring effects. These techniques consist mainly of statistical relationships derived from 1850-1950 network data and of patterns revealed by analysis of paleoclimatic data. An important part of the Soviet effort in anthropogenic climate-change studies is empirical techniques that represent independent verification of the results of theoretical climate models.

  10. A dynamic model for the global cycling of anthropogenic vanadium - article no. GB4021

    SciTech Connect

    Hope, B.K.

    2008-12-15

    Vanadium is a major trace metal in fossil fuels. Combustion of residual fuel oils and coal in industrialized economies is recognized as the major source of anthropogenic vanadium. A dynamic mass balance model assessed the influence of anthropogenic inputs on the global distribution and cycling of vanadium between 1700 and 2100 assuming different fossil fuel consumption and V production (mining) scenarios. Anthropogenic V sources were divided into fossil fuel combustion, industrial, and domestic (nonindustrial human activity). By 2050, inputs of anthropogenic V could comprise approximate to 75-85% of those to the atmosphere, approximate to 21-33% to ocean dissolved, approximate to 9-13% to ocean particulate, and approximate to 28-43% of inputs to land; with between approximate to 61-64% of all anthropogenic inputs attributable to fossil fuel combustion. Contributions from combustion and industrial sources, although dominant relative to contributions from domestic sources between 1900 and 2100, were estimated to peak between 2000 and 2050. Accumulation of anthropogenic V on land and in the ocean apparently occurs because natural removal processes are unable to cope with increasing amounts and rates of anthropogenic contributions. Impacts or hazards associated with anthropogenic inputs are unlikely to be discernible or significant on a global scale, but may be measurable and meaningful at smaller scales (coastal waters, continental shelves, and bays), in the locality of specific sources, or given an unfavorable exposure scenario.

  11. Detecting anthropogenic footprints in sea level rise

    PubMed Central

    Dangendorf, Sönke; Marcos, Marta; Müller, Alfred; Zorita, Eduardo; Riva, Riccardo; Berk, Kevin; Jensen, Jürgen

    2015-01-01

    While there is scientific consensus that global and local mean sea level (GMSL and LMSL) has risen since the late nineteenth century, the relative contribution of natural and anthropogenic forcing remains unclear. Here we provide a probabilistic upper range of long-term persistent natural GMSL/LMSL variability (P=0.99), which in turn, determines the minimum/maximum anthropogenic contribution since 1900. To account for different spectral characteristics of various contributing processes, we separate LMSL into two components: a slowly varying volumetric component and a more rapidly changing atmospheric component. We find that the persistence of slow natural volumetric changes is underestimated in records where transient atmospheric processes dominate the spectrum. This leads to a local underestimation of possible natural trends of up to ∼1 mm per year erroneously enhancing the significance of anthropogenic footprints. The GMSL, however, remains unaffected by such biases. On the basis of a model assessment of the separate components, we conclude that it is virtually certain (P=0.99) that at least 45% of the observed increase in GMSL is of anthropogenic origin. PMID:26220773

  12. DISCRIMINATING THE BENTHIC EFFECTS OF ANTHROPOGENIC POINT SOURCES FROM SALINITY AND NITROGEN LOADING

    EPA Science Inventory

    To evaluate the influence of anthropogenic point sources on estuarine systems, environmental managers must be able to discern the level and effects of significant natural factors and nonpoint source inputs. We compared benthic community state, salinity and dissolved inorganic nit...

  13. Forging the anthropogenic iron cycle.

    PubMed

    Wang, Tao; Müller, Daniel B; Graedel, T E

    2007-07-15

    Metallurgical iron cycles are characterized for four anthropogenic life stages: production, fabrication and manufacturing, use, and waste management and recycling. This analysis is conducted for year 2000 and at three spatial levels: 68 countries and territories, nine world regions, and the planet. Findings include the following: (1) contemporary iron cycles are basically open and substantially dependent on environmental sources and sinks; (2) Asia leads the world regions in iron production and use; Oceania, Latin America and the Caribbean, Africa, and the Commonwealth of Independent States present a highly production-biased iron cycle; (3) purchased scrap contributes a quarter of the global iron and steel production; (4) iron exiting use is three times less than that entering use; (5) about 45% of global iron entering use is devoted to construction, 24% is devoted to transport equipment, and 20% goes to industrial machinery; (6) with respect to international trade of iron ore, iron and steel products, and scrap, 54 out of the 68 countries are net iron importers, while only 14 are net exporters; (7) global iron discharges in tailings, slag, and landfill approximate one-third of the iron mined. Overall, these results provide a foundation for studies of iron-related resource policy, industrial development, and waste and environmental management.

  14. Watershed nutrient inputs, phytoplankton accumulation, and C stocks in Chesapeake Bay

    NASA Astrophysics Data System (ADS)

    Fisher, T. R.; Boynton, W. R.; Hagy, J. D.

    2002-12-01

    Inputs of N and P to Chesapeake Bay have been enhanced by anthropogenic activities. Fertilizers, urbanization, N emissions, and industrial effluents contribute to point and diffuse sources currently 2-7X higher for P and 5-20X higher for N than those from undisturbed watersheds. Enhanced nutrient inputs cause phytoplankton blooms which obscure visibility, eliminate submerged grasses, and influence the distribution of C within the Bay. Accumulations of dissolved organic and particulate organic C lead to enhanced microbial respiration in isolated bottom waters, and dissolved oxygen is seasonally reduced to trace levels during summer. Cultural eutrophication is not unique to Chesapeake Bay. Although some estuaries such as the Delaware, Hudson, and San Francisco Bay also have high anthropogenic inputs, these estuaries have much shorter residence times, and much of the N and P may be exported to the coastal ocean. However, in Chesapeake Bay, with residence times >2 months, internal processing of watershed inputs results in local algal blooms within the estuary. Watershed restoration strategies for Chesapeake watersheds have had limited success to date. Groundwaters are enriched with nitrate, and the long residence times of groundwaters mean slow responses to watershed improvements. The few successes in the Chesapeake have been associated with point source reductions, although continued human population growth can easily override restoration efforts. Widespread improvement in water quality has yet to occur, but the limited successes show that the Bay responds to load changes.

  15. Impacts of Anthropogenic Heat on Summertime Rainfall in Beijing

    NASA Astrophysics Data System (ADS)

    Nie, W.; Zaitchik, B. F.; Ni, G.; Sun, T.

    2016-12-01

    Anthropogenic heat is an important component of the urban energy budgets that can affect land surface and atmospheric boundary layer processes. Representation of anthropogenic heat in numerical climate modeling systems is, therefore, important when simulating urban meteorology and climate, and has the potential to improve weather forecasts, climate process studies, and energy demand analysis. Here, we incorporate spatiotemporally dynamic anthropogenic heat data estimated by the Building Effects Parameterization and Building Energy Model (BEP-BEM) into the Weather Research and Forecasting system (WRF) to investigate its impact on simulation of summertime rainfall in Beijing, China. Simulations of four local rainfall events with and without anthropogenic heat indicate that anthropogenic heat leads to increased rainfall over the urban area. For all four events, anthropogenic heat emission increases sensible heat flux, enhances mixing and turbulent energy transport, lifts PBL height, increases dry static energy and destabilizes the atmosphere in urban areas through thermal perturbation and strong upwelling motion during the pre-storm period, resulting in enhanced convergence during the major rainfall period. Intensified rainfall leads to greater atmospheric dry-down during the storm and a higher post-storm LCL.

  16. Evolution of Efficient Pathways for Degradation of Anthropogenic Chemicals

    PubMed Central

    Copley, Shelley D.

    2010-01-01

    Anthropogenic compounds used as pesticides, solvents, and explosives often persist in the environment and can cause toxicity to humans and wildlife. The persistence of anthropogenic compounds is due to their recent introduction into the environment; microbes in soil and water have had relatively little time to evolve efficient mechanisms for degradation of these novel compounds. Some anthropogenic compounds are easily degraded, while others are degraded very slowly or only partially, leading to accumulation of toxic products. This review examines the factors that affect the ability of microbes to degrade anthropogenic compounds and the mechanisms by which novel pathways emerge in nature. New approaches for engineering microbes with enhanced degradative abilities include assembly of pathways using enzymes from multiple organisms, directed evolution of inefficient enzymes, and genome shuffling to improve microbial fitness under the challenging conditions posed by contaminated environments. PMID:19620997

  17. Anthropogenic forcings on the surficial osmium cycle.

    PubMed

    Rauch, Sebastien; Peucker-Ehrenbrink, Bernhard; Kylander, Malin E; Weiss, Dominik J; Martinez-Cortizas, Antonio; Heslop, David; Olid, Carolina; Mighall, Tim M; Hemond, Harold F

    2010-02-01

    Osmium is among the least abundant elements in the Earth's continental crust. Recent anthropogenic Os contamination of the environment from mining and smelting activities, automotive catalytic converter use, and hospital discharges has been documented. Here we present evidence for anthropogenic overprinting of the natural Os cycle using a ca. 7000-year record of atmospheric Os deposition and isotopic composition from an ombrotrophic peat bog in NW Spain. Preanthropogenic Os accumulation in this area is 0.10 +/- 0.04 ng m(-2) y(-1). The oldest strata showing human influence correspond to early metal mining and processing on the Iberian Peninsula (ca. 4700-2500 cal. BP). Elevated Os accumulation rates are found thereafter with a local maximum of 1.1 ng m(-2) y(-1) during the Roman occupation of the Iberian Peninsula (ca. 1930 cal. BP) and a further increase starting in 1750 AD with Os accumulation reaching 30 ng m(-2) y(-1) in the most recent samples. Osmium isotopic composition ((187)Os/(188)Os) indicates that recent elevated Os accumulation results from increased input of unradiogenic Os from industrial and automotive sources as well as from enhanced deposition of radiogenic Os through increased fossil fuel combustion and soil erosion. We posit that the rapid increase in catalyst-equipped vehicles, increased fossil fuel combustion, and changes in land-use make the changes observed in NW Spain globally relevant.

  18. Provenancing anthropogenic Pb within the fluvial environment: developments and challenges in the use of Pb isotopes.

    PubMed

    Bird, Graham

    2011-05-01

    The potentially deleterious presence of ore-derived Pb within riverine environments has been a long-term impact of industrial and anthropogenic activity in general. The surface drainage network has been widely established as a key transport mechanism and storage environment for anthropogenically-derived Pb and other potentially harmful trace metals. Lead isotopes ((204)Pb, (206)Pb, (207)Pb, (208)Pb) have been utilized as a geochemical tracer of Pb origin in a variety of environmental media, notably in atmospheric aerosols. However, given the relative complexity of dispersal processes within riverine environments, the use of Pb isotopes as geochemical tracers has been relatively limited and it is only relatively recently that a growing body of research has applied Pb isotopes to provenancing fluvially-dispersed Pb. This paper seeks to synthesize the developments in the use of Pb isotopes within riverine environments. In doing so it outlines the Pb-isotope fingerprinting technique and associated analytical developments, and assesses the application of Pb isotopes in establishing the origin and dispersal mechanisms of anthropogenically- and geogenically-derived Pb at a range of temporal and spatial scales. Of particular importance are the approaches quantifying source inputs using Pb isotopic signatures and the challenges faced, and options available in quantifying source inputs at the catchment scale; where Pb may be sourced from a variety (n=>2) of sources. The Pb isotopic signature of contemporary riverine Pb loads is shown to reflect a spatially complex influence of mineralization chemistry, anthropogenic activity as well as the hydro-morphological controls exerted upon Pb release, dispersal and storage. In relation to this, the long-term environmental legacy, and its influence upon Pb fingerprinting studies, of tetra-ethyl Pb, sourced from the combustion of leaded-petrol is also discussed. Finally, this paper places the use of Pb isotopes in the context of

  19. Stable lead isotopic analyses of historic and contemporary lead contamination of San Francisco Bay estuary

    USGS Publications Warehouse

    Ritson, P.I.; Bouse, R.M.; Flegal, A.R.; Luoma, S.N.

    1999-01-01

    Variations in stable lead isotopic composition (240Pb, 206Pb, 207Pb, 208Pb) in three sediment cores from the San Francisco Bay estuary document temporal changes in sources of lead during the past two centuries. Sediment, with lead from natural geologic sources, and relatively homogeneous lead isotopic compositions are overlain by sediments whose isotopic compositions indicate change in the sources of lead associated with anthropogenic modification of the estuary. The first perturbations of lead isotopic composition in the cores occur in the late 1800s concordant with the beginning of industrialization around the estuary. Large isotopic shifts, toward lower 206Pb/207Pb, occur after the turn of the century in both Richardson and San Pablo Bays. A similar relationship among lead isotopic compositions and lead concentrations in both Bays suggest contamination from the same source (a lead smelter). The uppermost sediments (post 1980) of all cores also have a relatively homogenous lead isotopic composition distinct from pre-anthropogenic and recent aerosol signatures. Lead isotopic compositions of leachates from fourteen surface sediments and five marsh samples from the estuary were also analyzed. These analyses suggest that the lead isotopic signature identified in the upper horizons of the cores is spatially homogeneous among recently deposited sediments throughout the estuary. Current aerosol lead isotopic compositions [Smith, D.R., Niemeyer, S., Flegal, A.R., 1992. Lead sources to California sea otters: industrial inputs circumvent natural lead biodepletion mechanisms. Environmental Research 57, 163-175] are distinct from the isotopic compositions of the surface sediments, suggesting that the major source of lead is cycling of historically contaminated sediments back through the water column. Both the upper core sediments and surface sediments apparently derive their lead predominantly from sources internal to the estuary. These results support the idea that

  20. Caracterisation of anthropogenic contribution to the coastal fluorescent organic matter

    NASA Astrophysics Data System (ADS)

    El Nahhal, Ibrahim; Nouhi, Ayoub; Mounier, Stéphane

    2015-04-01

    It is known that most of the coastal fluorescent organic matter is of a terrestrial origin (Parlanti, 2000; Tedetti, Guigue, & Goutx, 2010). However, the contribution of the anthropogenic organic matter to this pool is not well defined and evaluated. In this work the monitoring of little bay (Toulon Bay, France) was done in the way to determine the organic fluorescent response during a winter period. The sampling campaign consisted of different days during the month of December, 2014 ( 12th, 15th, 17th, 19th) on 21 different sampling sites for the fluorescence measurements (without any filtering of the samples) and the whole month of December for the bacterial and the turbidity measurements. Excitation Emission Matrices (EEMs) of fluorescence (from 200 to 400 nm and 220 to 420 nm excitation and emission range) were treated by parallel factor analysis (PARAFAC).The parafac analysis of the EEM datasets was conducted using PROGMEEF software in Matlab langage. On the same time that the turbidity and bacterial measurement (particularly the E.Coli concentration) were determined. The results gives in a short time range, information on the the contribution of the anthropogenic inputs to the coastal fluorescent organic matter. In addition, the effect of salinity on the photochemical degradation of the anthropogenic organic matter (especially those from wastewater treatment plants) will be studied to investigate their fate in the water end member by the way of laboratory experiments. Parlanti, E. (2000). Dissolved organic matter fluorescence spectroscopy as a tool to estimate biological activity in a coastal zone submitted to anthropogenic inputs. Organic Geochemistry, 31(12), 1765-1781. doi:10.1016/S0146-6380(00)00124-8 Tedetti, M., Guigue, C., & Goutx, M. (2010). Utilization of a submersible UV fluorometer for monitoring anthropogenic inputs in the Mediterranean coastal waters. Marine Pollution Bulletin, 60(3), 350-62. doi:10.1016/j.marpolbul.2009.10.018

  1. Impact of anthropogenic atmospheric nitrogen and sulfur deposition on ocean acidification and the inorganic carbon system.

    PubMed

    Doney, Scott C; Mahowald, Natalie; Lima, Ivan; Feely, Richard A; Mackenzie, Fred T; Lamarque, Jean-Francois; Rasch, Phil J

    2007-09-11

    Fossil fuel combustion and agriculture result in atmospheric deposition of 0.8 Tmol/yr reactive sulfur and 2.7 Tmol/yr nitrogen to the coastal and open ocean near major source regions in North America, Europe, and South and East Asia. Atmospheric inputs of dissociation products of strong acids (HNO(3) and H2SO(4)) and bases (NH(3)) alter surface seawater alkalinity, pH, and inorganic carbon storage. We quantify the biogeochemical impacts by using atmosphere and ocean models. The direct acid/base flux to the ocean is predominately acidic (reducing total alkalinity) in the temperate Northern Hemisphere and alkaline in the tropics because of ammonia inputs. However, because most of the excess ammonia is nitrified to nitrate (NO(3)(-)) in the upper ocean, the effective net atmospheric input is acidic almost everywhere. The decrease in surface alkalinity drives a net air-sea efflux of CO(2), reducing surface dissolved inorganic carbon (DIC); the alkalinity and DIC changes mostly offset each other, and the decline in surface pH is small. Additional impacts arise from nitrogen fertilization, leading to elevated primary production and biological DIC drawdown that reverses in some places the sign of the surface pH and air-sea CO(2) flux perturbations. On a global scale, the alterations in surface water chemistry from anthropogenic nitrogen and sulfur deposition are a few percent of the acidification and DIC increases due to the oceanic uptake of anthropogenic CO(2). However, the impacts are more substantial in coastal waters, where the ecosystem responses to ocean acidification could have the most severe implications for mankind.

  2. Impact of anthropogenic atmospheric nitrogen and sulfur deposition on ocean acidification and the inorganic carbon system

    PubMed Central

    Doney, Scott C.; Mahowald, Natalie; Lima, Ivan; Feely, Richard A.; Mackenzie, Fred T.; Lamarque, Jean-Francois; Rasch, Phil J.

    2007-01-01

    Fossil fuel combustion and agriculture result in atmospheric deposition of 0.8 Tmol/yr reactive sulfur and 2.7 Tmol/yr nitrogen to the coastal and open ocean near major source regions in North America, Europe, and South and East Asia. Atmospheric inputs of dissociation products of strong acids (HNO3 and H2SO4) and bases (NH3) alter surface seawater alkalinity, pH, and inorganic carbon storage. We quantify the biogeochemical impacts by using atmosphere and ocean models. The direct acid/base flux to the ocean is predominately acidic (reducing total alkalinity) in the temperate Northern Hemisphere and alkaline in the tropics because of ammonia inputs. However, because most of the excess ammonia is nitrified to nitrate (NO3−) in the upper ocean, the effective net atmospheric input is acidic almost everywhere. The decrease in surface alkalinity drives a net air–sea efflux of CO2, reducing surface dissolved inorganic carbon (DIC); the alkalinity and DIC changes mostly offset each other, and the decline in surface pH is small. Additional impacts arise from nitrogen fertilization, leading to elevated primary production and biological DIC drawdown that reverses in some places the sign of the surface pH and air–sea CO2 flux perturbations. On a global scale, the alterations in surface water chemistry from anthropogenic nitrogen and sulfur deposition are a few percent of the acidification and DIC increases due to the oceanic uptake of anthropogenic CO2. However, the impacts are more substantial in coastal waters, where the ecosystem responses to ocean acidification could have the most severe implications for mankind. PMID:17804807

  3. Anthropogenic versus natural control on trace element and Sr-Nd-Pb isotope stratigraphy in peat sediments of southeast Florida (USA), ˜1500 AD to present

    NASA Astrophysics Data System (ADS)

    Kamenov, George D.; Brenner, Mark; Tucker, Jaimie L.

    2009-06-01

    Analysis of a well-dated peat core from Blue Cypress Marsh (BCM) provides a detailed record of natural and anthropogenic factors that controlled the geochemical cycles of a number of trace elements in Florida over the last five centuries. The trace elements were divided into "natural" and "anthropogenic" groups using concentration trends from the bottom to the top of the core. The "natural" group includes Li, Sc, Cr, Co, Ga, Ge, Zr, Nb, Cs, Ba, Hf, Y, Ta, Th, and REE (Rare Earth Elements). These elements show similar concentrations throughout the core, indicating that changes in human activities after European arrival in the "New World" did not affect their geochemical cycles. The "anthropogenic" group includes Pb, Cu, Zn, V, Sb, Sn, Bi, and Cd. Upcore enrichment of these elements indicates enhancement by anthropogenic activities. From the early 1500s to present, fluxes of the "anthropogenic" metals to the marsh increased significantly, with modern accumulation rates several-fold (e.g., V) to hundreds of times (e.g., Zn) greater than pre-colonial rates. The dominant input mechanism for trace elements from both groups to the marsh has been atmospheric deposition. Atmospheric input of a number of the elements, including the anthropogenic metals, was dominated by local sources during the last century. For several elements, long-distant transport may be important. For instance, REE and Nd isotopes provide evidence for long-range atmospheric transport dominated by Saharan dust. The greatest increase in flux of the "anthropogenic" metals occurred during the 20th century and was caused by changes in the chemical composition of atmospheric deposition entering the marsh. Increased atmospheric inputs were a consequence of several anthropogenic activities, including fossil fuel combustion (coal and oil), agricultural activities, and quarrying and mining operations. Pb and V exhibit similar trends, with peak accumulation rates in 1970. The principal anthropogenic source of V

  4. Historic and Industrial Lead within the Northwest Pacific Ocean Evidenced by Lead Isotopes in Seawater.

    PubMed

    Zurbrick, Cheryl M; Gallon, Céline; Flegal, A Russell

    2017-02-07

    We report the continued lead (Pb) contamination of the Northwest Pacific Ocean in 2002 and present the first comprehensive Pb isotope data set for that region. In the upper ocean, a Pb concentration maxima (64-113 pmol kg(-1)) extended throughout the entire North Pacific Subtropical Gyre (NPSG). We determined most of the Pb in this feature was from industrial emissions by many nations in the 1980s and 1990s, with the largest contributions from leaded gasoline emissions. In contrast, the deep water (>1000 m) Pb concentrations were lower (6-37 pmol kg(-1)), and constituted a mix of background (natural) Pb and anthropogenic Pb inputs from preceding decades. Deep water below the Western Subarctic Gyre (WSAG) contained more industrial Pb than below the NPSG, which was attributed to a calculated 60-fold greater flux of particulate Pb to abyssal waters near the Asian continent. Assuming Pb isotope compositions in the North Pacific Ocean were homogeneous prior to large-scale 20th century anthropogenic inputs, this evidence suggests a relatively faster change in Pb isotope ratios of North Pacific deep water below the WSAG versus the NPSG.

  5. The Nitrogen Legacy: Evidence of Soil Nitrogen Accumulation in Anthropogenic Landscapes

    NASA Astrophysics Data System (ADS)

    Van Meter, K. J.; Basu, N. B.

    2013-12-01

    Human modification of the nitrogen (N) cycle has resulted in increased flows of reactive N, with some suggesting that planetary boundaries for maintaining human and ecosystem health have been exceeded. Persistence of large hypoxic zones in inland and coastal waters created by elevated concentrations of nitrate is one of the most significant impacts of such increased flows. While the need to manage these flows and their associated ecological impacts is recognized, best management practices to reduce stream N concentrations have had only limited success. Some have attributed this lack of success to an accumulation of legacy N stores from decades of fertilizer application. Nitrogen mass balance studies seem to suggest an ongoing retention of N within anthropogenic landscapes, but the exact form and location of this legacy N and the associated retention rates are subject to question. Here we introduce an unprecedented analysis of long-term soil data from the Mississippi River Basin (MRB) revealing significant increases in total N (TN) content. We show that TN accumulation for the MRB accounts for 49% of net anthropogenic N inputs (NANI), which complements previous work indicating that approximately 25% of net inputs are lost as riverine output. These findings significantly reduce the uncertainty associated with basin-level N retention. Further, our results demonstrate that, despite conventional wisdom of intensive agriculture leading to a depletion of TN, an accumulation of N is occurring in the deeper subsurface (25 - 100 cm) that compensates for depletion in the plow layer (0-25 cm). These legacy N stores may lead to time lags between changes in management practices and decreasing N concentrations in stream waters, thus resulting in multidecadal effects on water quality in agricultural watersheds.

  6. Climate forcing by anthropogenic aerosols

    NASA Technical Reports Server (NTRS)

    Charlson, R. J.; Schwartz, S. E.; Hales, J. M.; Cess, R. D.; Coakley, J. A., Jr.; Hansen, J. E.; Hofmann, D. J.

    1992-01-01

    Although long considered to be of marginal importance to global climate change, tropospheric aerosol contributes substantially to radiative forcing, and anthropogenic sulfate aerosol, in particular, has imposed a major perturbation to this forcing. Both the direct scattering of short-wavelength solar radiation and the modification of the shortwave reflective properties of clouds by sulfate aerosol particles increase planetary albedo, thereby exerting a cooling influence on the planet. Current climate forcing due to anthropogenic sulfate is estimated to be -1 to -2 watts per square meter, globally averaged. This perturbation is comparable in magnitude to current anthropogenic greenhouse gas forcing but opposite in sign. Thus, the aerosol forcing has likely offset global greenhouse warming to a substantial degree. However, differences in geographical and seasonal distributions of these forcings preclude any simple compensation. Aerosol effects must be taken into account in evaluating anthropogenic influences on past, current, and projected future climate and in formulating policy regarding controls on emission of greenhouse gases and sulfur dioxide. Resolution of such policy issues requires integrated research on the magnitude and geographical distribution of aerosol climate forcing and on the controlling chemical and physical processes.

  7. Climate forcing by anthropogenic aerosols

    NASA Technical Reports Server (NTRS)

    Charlson, R. J.; Schwartz, S. E.; Hales, J. M.; Cess, R. D.; Coakley, J. A., Jr.; Hansen, J. E.; Hofmann, D. J.

    1992-01-01

    Although long considered to be of marginal importance to global climate change, tropospheric aerosol contributes substantially to radiative forcing, and anthropogenic sulfate aerosol, in particular, has imposed a major perturbation to this forcing. Both the direct scattering of short-wavelength solar radiation and the modification of the shortwave reflective properties of clouds by sulfate aerosol particles increase planetary albedo, thereby exerting a cooling influence on the planet. Current climate forcing due to anthropogenic sulfate is estimated to be -1 to -2 watts per square meter, globally averaged. This perturbation is comparable in magnitude to current anthropogenic greenhouse gas forcing but opposite in sign. Thus, the aerosol forcing has likely offset global greenhouse warming to a substantial degree. However, differences in geographical and seasonal distributions of these forcings preclude any simple compensation. Aerosol effects must be taken into account in evaluating anthropogenic influences on past, current, and projected future climate and in formulating policy regarding controls on emission of greenhouse gases and sulfur dioxide. Resolution of such policy issues requires integrated research on the magnitude and geographical distribution of aerosol climate forcing and on the controlling chemical and physical processes.

  8. Historical economic and environmental policies influencing trace metal inputs in Montevideo Bay, Río de la Plata.

    PubMed

    Bueno, C; Brugnoli, E; Figueira, R C L; Muniz, P; Ferreira, P A L; García Rodríguez, F

    2016-12-15

    Montevideo Bay is located in the middle zone of the Rio de la Plata, and since the foundation of the city, several key economic and environmental policies affected the industry, and thus, metal inputs into this ecosystem. The aim of this study is to evaluate the sedimentary geochemical record of Montevideo Bay, in order to determine the historical inputs of anthropogenic metals to the system. In addition, environmental and economic policies of the country were taken into account to infer the relationship between them and the historic metal input. Concentrations of aluminum, chromium, copper, lead, scandium and zinc were analyzed and the EF and SPI indices were calculated. The analysis showed that since Montevideo foundation, metal concentrations increased in accordance with industry development, and the indices as well as the metal concentration represent a reliable footprint of the history of different economic and environmental policies influencing historical industrial activities. Copyright © 2016 Elsevier Ltd. All rights reserved.

  9. Lead and strontium isotopes as indicators for mixing processes of waters in the former mine 'Himmelfahrt Fundgrube', Freiberg (Germany).

    PubMed

    Heidel, Claudia; Tichomirowa, Marion; Matschullat, Jörg

    2007-12-01

    To pinpoint the origin and mixing processes of mine waters, different mine water types from the polymetallic sulphide ore deposit 'Himmelfahrt Fundgrube' (Freiberg, Germany) were analysed by thermal ionisation mass spectrometry using lead and strontium isotope ratios. Results show that the lead isotope composition of different mine waters results from a mixture of at least two sources: released lead from oxidised sulphide ores (mainly galena) and anthropogenic lead from groundwater. Furthermore, there are indications for an additional lead source. Strontium isotopes in mine waters identify at least three different sources: released strontium from weathered host rock (Grey Gneisses), released strontium from weathered gangue carbonates, and probably strontium from anthropogenic inputs. Contrary to former oxygen and sulphur isotope studies, strontium isotope compositions as well as hydrochemical parameters show the important role of gangue carbonates as an element source in mine waters.

  10. Ocean N2O Emissions : Recent Global Estimates and Anthropogenically Influenced Changes

    NASA Astrophysics Data System (ADS)

    Suntharalingam, P.; Buithenuis, E.; Andrews, O.; Le Quere, C.

    2016-12-01

    Oceanic N2O is produced by microbial activity during organic matter cycling in the subsurface ocean; its production mechanisms display sensitivity to ambient oxygen level. In the oxic ocean, N2O is produced as a byproduct during the oxidation of ammonia to nitrate, mediated by ammonia oxidizing bacteria and archea. N2O is also produced and consumed in sub-oxic and anoxic waters through the action of marine denitrifiers during the multi-step reduction of nitrate to gaseous nitrogen. The oceanic N2O distribution therefore displays significant heterogeneity with background levels of 10-20 nmol/l in the well-oxygenated ocean basins, high concentrations (> 40 nmol/l) in hypoxic waters, and N2O depletion in the core of ocean oxygen minimum zones (OMZs). Oceanic N2O emissions are estimated to account for up to a third of the pre-industrial N2O fluxes to the atmosphere, however the natural cycle of ocean N2O has been perturbed in recent decades by inputs of anthropogenically derived nutrient, and by the impacts of climate change. Anthropogenic nitrogen inputs (e.g., NOx and NHy from fossil fuel combustion and agricultural fertilizer) enter the ocean via atmospheric deposition and riverine fluxes, influencing oceanic N2O production via their impact on the marine organic matter cycle. In addition, climate variations associated with surface ocean warming affect oceanic circulation and nutrient transport pathways, influencing marine productivity and the ventilation of oxygen minimum zones. Recent studies have suggested that possible expansion of oceanic OMZs in a warming climate could lead to significant changes in N2O production and fluxes from these regions. We will summarise the current state of knowledge on the ocean N2O budget and net flux to the atmosphere. Recently reported estimates have been based on (i) empirical relationships derived from ocean tracer data (e.g., involving excess N2O and Apparent Oxygen Utilization (AOU) correlations), (ii) ocean biogeochemical

  11. Estimating animal mortality from anthropogenic hazards

    EPA Science Inventory

    Carcass searches are a common method for studying the risk of anthropogenic hazards to wildlife, including non-target poisoning and collisions with anthropogenic structures. Typically, numbers of carcasses found must be corrected for scavenging rates and imperfect detection. Para...

  12. Estimating animal mortality from anthropogenic hazards

    EPA Science Inventory

    Carcass searches are a common method for studying the risk of anthropogenic hazards to wildlife, including non-target poisoning and collisions with anthropogenic structures. Typically, numbers of carcasses found must be corrected for scavenging rates and imperfect detection. Para...

  13. Anthropogenic disturbance and the risk of flea-borne disease transmission

    Treesearch

    Megan M. Friggens; Paul Beier

    2010-01-01

    Anthropogenic disturbance may lead to the spread of vector-borne diseases through effects on pathogens, vectors, and hosts. Identifying the type and extent of vector response to habitat change will enable better and more accurate management strategies for anthropogenic disease spread. We compiled and analyzed data from published empirical studies to test for patterns...

  14. A synthesis of regional inputs and damage costs of reactive nitrogen in the United States

    EPA Science Inventory

    We estimated the fate of N in crops and in the environment (air, land, freshwater, groundwater, and coastal zones) with published coefficients describing nutrient uptake efficiency, gaseous emissions, and leaching losses. Benefits and damage costs of anthropogenic N inputs were ...

  15. A synthesis of regional inputs and damage costs of reactive nitrogen in the United States

    EPA Science Inventory

    We estimated the fate of N in crops and in the environment (air, land, freshwater, groundwater, and coastal zones) with published coefficients describing nutrient uptake efficiency, gaseous emissions, and leaching losses. Benefits and damage costs of anthropogenic N inputs were ...

  16. Assessment of global industrial-age anthropogenic arsenic contamination.

    PubMed

    Han, Fengxiang X; Su, Yi; Monts, David L; Plodinec, M John; Banin, Amos; Triplett, Glover E

    2003-09-01

    Arsenic, a carcinogenic trace element, threatens not only the health of millions of humans and other living organisms, but also global sustainability. We present here, for the first time, the global industrial-age cumulative anthropogenic arsenic production and its potential accumulation and risks in the environment. In 2000, the world cumulative industrial-age anthropogenic arsenic production was 4.53 million tonnes. The world-wide coal and petroleum industries accounted for 46% of global annual gross arsenic production, and their overall contribution to industrial-age gross arsenic production was 27% in 2000. Global industrial-age anthropogenic As sources (as As cumulative production) follow the order: As mining production>As generated from coal>As generated from petroleum. The potential industrial-age anthropogenic arsenic input in world arable surface in 2000 was 2.18 mg arsenic kg(-1), which is 1.2 times that in the lithosphere. The development of substitute materials for arsenic applications in the agricultural and forestry industries and controls of arsenic emissions from the coal industry may be possible strategies to significantly decrease arsenic pollution sources and dissipation rates into the environment.

  17. Stable nitrogen isotopes in the turtle grass Thalassia testudinum from the Mexican Caribbean: Implications of anthropogenic development

    NASA Astrophysics Data System (ADS)

    Sánchez, Alberto; Ortiz-Hernández, Ma. Concepción; Talavera-Sáenz, Ana; Aguíñiga-García, Sergio

    2013-12-01

    Nutrient inputs associated with population growth threaten the integrity of coastal ecosystems. To assess the rapid increase in tourism, we compared the δ15N from Thalassia testudinum collected at sites with different levels of tourism development to detect the N inputs of wastewater discharge (WD) along the coast of Quintana Roo. The contributions of nitrogen enriched in 15N are directly related to the increase of WD inputs in areas of tourism development (Nichupte Lagoon in Cancun) and decreased toward Bahia Akumal and Tulum. The δ15N from T. testudinum was significantly lower at Mahahual and Puerto Morelos. In areas of the lowest development and with tourist activity restricted, such as the Yum Balam Reserve and Sian Ka'an Biosphere Reserve, the δ15N values were relatively enriched compared to Mahahual and Puerto Morelos. Therefore, Puerto Morelos and Mahahual may be used for baseline isotopic monitoring where tourist activities are growing and can lead to environmental pressure on the reef lagoon ecosystem. The anthropogenic N input has the potential to impact, both environmentally and economically, the seagrass meadows and the coral reefs along the coast of Quintana Roo and the Caribbean.

  18. Input, Interaction, and Second Language Production.

    ERIC Educational Resources Information Center

    Gass, Susan M.; Varonis, Evangeline Marlos

    1994-01-01

    This study investigated the relationship among input, interaction, and second-language production among 16 native-nonnative dyads. The results indicated that both modified input and interaction initiated by the native speaker lead to greater comprehension by the nonnative speaker, as measured by task performance. (Contains 48 references.) (MDM)

  19. Ecology of estuaries: Anthropogenic effects

    SciTech Connect

    Kennish, M.J.

    1992-01-01

    Estuaries and near-shore oceanic water are subjected to a multitude of human wastes. The principal objective of this book is to examine anthropogenic effects on estuaries, and it focuses primarily on contaminants in coastal systems. Covered within various chapters are the following topics: waste disposal strategies; definition and classification of pollutants (including organic loading, oil pollution, polynuclear aromatic hydrocarbons; chlorinated hydrocarbons; heavy metals; radionuclides) biological impacts; waste management; impacts of power plants; dredging and spoil disposal; case studies, primarily Chesapeake Bay. The book serves as a text and as a reference.

  20. Bilinearity in Spatiotemporal Integration of Synaptic Inputs

    PubMed Central

    Li, Songting; Liu, Nan; Zhang, Xiao-hui; Zhou, Douglas; Cai, David

    2014-01-01

    Neurons process information via integration of synaptic inputs from dendrites. Many experimental results demonstrate dendritic integration could be highly nonlinear, yet few theoretical analyses have been performed to obtain a precise quantitative characterization analytically. Based on asymptotic analysis of a two-compartment passive cable model, given a pair of time-dependent synaptic conductance inputs, we derive a bilinear spatiotemporal dendritic integration rule. The summed somatic potential can be well approximated by the linear summation of the two postsynaptic potentials elicited separately, plus a third additional bilinear term proportional to their product with a proportionality coefficient . The rule is valid for a pair of synaptic inputs of all types, including excitation-inhibition, excitation-excitation, and inhibition-inhibition. In addition, the rule is valid during the whole dendritic integration process for a pair of synaptic inputs with arbitrary input time differences and input locations. The coefficient is demonstrated to be nearly independent of the input strengths but is dependent on input times and input locations. This rule is then verified through simulation of a realistic pyramidal neuron model and in electrophysiological experiments of rat hippocampal CA1 neurons. The rule is further generalized to describe the spatiotemporal dendritic integration of multiple excitatory and inhibitory synaptic inputs. The integration of multiple inputs can be decomposed into the sum of all possible pairwise integration, where each paired integration obeys the bilinear rule. This decomposition leads to a graph representation of dendritic integration, which can be viewed as functionally sparse. PMID:25521832

  1. The Role of Anthropogenic Stratigraphy in River Restoration Projects

    NASA Astrophysics Data System (ADS)

    Evans, J. E.; Webb, L. D.

    2012-12-01

    As part of a river restoration project and removal of a low-head dam on the Ottawa River (northwestern Ohio and southeastern Michigan) in 2007, a longer-term project was initiated to assess anthropogenic changes of the Ottawa River fluvial system. A composite stratigraphic section 4.5 m in length was constructed by stratigraphic correlation from three trenches up to 2.5 m in depth and 14 vibracores up to 2.5 m in length, all within a small region (<0.5 km2 in area). At various stratigraphic levels, the cores contain a suite of anthropogenic materials including fragments of bricks and cement blocks, pieces of modern ceramics, fragments of plastic and rubber tires, intact or pieces of glass bottles, and one horizon of displaced railroad ties. Age control for the composite section is provided by 4 14C dates, 6 OSL dates, and one bottle with a date stamp. Two prominent flood horizons are indicated in multiple trenches or cores, and identified as the historic floods of 1913 and 1959. The data show the following major changes in the fluvial system over time: (1) prior to approximately 5 Ka, the river system was transporting mineral-rich sediment and formed meandering point-bar sequences approximately 1.5 m thick; (2) between approximately 5 Ka and 200 YBP, the river system was transporting organic-rich sediment (i.e., blackwater stream) bordered by riparian wetlands accumulating peat (part of the regional "Great Black Swamp" discovered by settlers from eastern North America); (3) between approximately 200 YBP and the early 1960s the river system was transporting mineral-rich sediment (i.e., brownwater stream), probably sourced from extensive land clearance for agriculture, which backfilled and overtopped the previous riparian wetlands and produced an series of thin channel fills interpreted as rapidly shifting avulsional channels; (4) since the early 1960s, sediment supply has exceeded sediment conveyance capacity, leading to vertical aggradation of approximately 1.7 m

  2. Anthropogenic radionuclides in the environment

    SciTech Connect

    Hu, Q; Weng, J; Wang, J

    2007-11-15

    Studies of radionuclides in the environment have entered a new era with the renaissance of nuclear energy and associated fuel reprocessing, geological disposal of high-level nuclear wastes, and concerns about national security with respect to nuclear non-proliferation. This work presents an overview of anthropogenic radionuclide contamination in the environment, as well as the salient geochemical behavior of important radionuclides. We first discuss the following major anthropogenic sources and current development that contribute to the radionuclide contamination of the environment: (1) nuclear weapons program; (2) nuclear weapons testing; (3) nuclear power plants; (4) commercial fuel reprocessing; (5) geological repository of high-level nuclear wastes, and (6) nuclear accidents. Then, we summarize the geochemical behavior for radionuclides {sup 99}Tc, {sup 129}I, and {sup 237}Np, because of their complex geochemical behavior, long half-lives, and presumably high mobility in the environment. Biogeochemical cycling and environment risk assessment must take into account speciation of these redox-sensitive radionuclides.

  3. Diagnosing Possible Anthropogenic Contributions to Colorado Floods in September 2013.

    NASA Astrophysics Data System (ADS)

    Pall, P.; Patricola, C. M.; Wehner, M. F.; Stone, D. A.

    2015-12-01

    Unusually heavy rainfall occurred over the Colorado Front Range during the second week of September 2013, with record or near-record totals recorded in several locations. It was associated predominantly with a stationary large-scale weather pattern (akin to the North American Monsoon, which occurs earlier in the year) that drove a strong plume of deep moisture inland from the Gulf of Mexico and eastern tropical Pacific towards the Front Range foothills. The resulting floods across the South Platte River basin impacted several thousands of people and many homes, roads, and businesses. A recent study using observational-based re-analysis to drive the regional WRF model finds that, given very little change in the large-scale weather pattern, there is an increase in atmospheric water vapour over northeast Colorado under anthropogenic climate warming, with a positive dynamical feedback drawing in moisture from further afield. This leads to a substantial increase in the magnitude and odds of heavy rainfall occurring over northeast Colorado during the rainy week of September 2013. Here we develop this work by including a hydrological modelling component in order to investigate any anthropogenic influence on the actual flood magnitude and occurrence across the South Platte basin during that time. We use WRF precipitation output from the aforementioned study - in both anthropogenic and non-anthropogenic configurations for September 2013 - to drive the recently developed high-resolution WRF-Hydro model over the basin and generate river runoff. Thus by comparing changes in runoff under the anthropogenic / non-anthropogenic driving conditions we assess any influence on the magnitude and odds of flood occurrence. Integral to this, we test the sensitivity of our results to hydrological parameters, such as infiltration, base flow, and land use/cover.

  4. Talking Speech Input.

    ERIC Educational Resources Information Center

    Berliss-Vincent, Jane; Whitford, Gigi

    2002-01-01

    This article presents both the factors involved in successful speech input use and the potential barriers that may suggest that other access technologies could be more appropriate for a given individual. Speech input options that are available are reviewed and strategies for optimizing use of speech recognition technology are discussed. (Contains…

  5. MDS MIC Catalog Inputs

    NASA Technical Reports Server (NTRS)

    Johnson-Throop, Kathy A.; Vowell, C. W.; Smith, Byron; Darcy, Jeannette

    2006-01-01

    This viewgraph presentation reviews the inputs to the MDS Medical Information Communique (MIC) catalog. The purpose of the group is to provide input for updating the MDS MIC Catalog and to request that MMOP assign Action Item to other working groups and FSs to support the MITWG Process for developing MIC-DDs.

  6. High input impedance amplifier

    NASA Technical Reports Server (NTRS)

    Kleinberg, Leonard L.

    1995-01-01

    High input impedance amplifiers are provided which reduce the input impedance solely to a capacitive reactance, or, in a somewhat more complex design, provide an extremely high essentially infinite, capacitive reactance. In one embodiment, where the input impedance is reduced in essence, to solely a capacitive reactance, an operational amplifier in a follower configuration is driven at its non-inverting input and a resistor with a predetermined magnitude is connected between the inverting and non-inverting inputs. A second embodiment eliminates the capacitance from the input by adding a second stage to the first embodiment. The second stage is a second operational amplifier in a non-inverting gain-stage configuration where the output of the first follower stage drives the non-inverting input of the second stage and the output of the second stage is fed back to the non-inverting input of the first stage through a capacitor of a predetermined magnitude. These amplifiers, while generally useful, are very useful as sensor buffer amplifiers that may eliminate significant sources of error.

  7. Tracing Anthropogenic Osmium around Japan using the Osmium Isotopic Composition of Macroalgae

    NASA Astrophysics Data System (ADS)

    Sproson, A. D.; Selby, D. S.; Suzuki, K.

    2016-12-01

    The present-day open ocean seawater 187Os/188Os value of 1.06 is seen to reflect the balance between unradiogenic mantle derived osmium (Os) and radiogenic continental Os. However, Os released by anthropogenic activities has been detected in coastal sediments, lakes, estuaries, rain and snow from sources such as sewage sludge, catalytic convertors, smelting, fossil fuel burning and use as a staining reagent, thereby impacting the global Os budget. Despite over two decades of research, contemporary Os inputs into the ocean are believed to be underestimated by a factor of 3, leading to discrepancies in oceanic Os residence times estimated from mass balance calculations. This, in part, is due to the problems associated with directly measuring ultra-low concentrations of Os in seawater. Recently, it has been proposed that the 187Os/188Os of macroalgae (seaweed) reflects that of the seawater in which it lives. This suggests macroalgae can act as a proxy for the Os isotopic composition of seawater. We present Os isotope data for macroalgae collected from Tokyo Bay, Osaka Bay, the Noto Peninsula, Izu Peninsula and Hokkaido. Macroalgae close to the major cities of Tokyo and Osaka exhibit unradiogenic 187Os/188Os values as low as 0.45, in agreement with published sediment data. As you move away from central Tokyo and Osaka, 187Os/188Os values become more radiogenic, reaching values as high as 0.95 due to the entrainment of more radiogenic seawater. Macroalgae from the less urbanised Noto and Izu Peninsulas show a radiogenic 187Os/188Os range of 0.70-0.91, close to global river estimates suggesting little contamination from anthropogenic processes. Deep-water species off the coast of Hokkaido exhibit 187Os/188Os values in agreement with published Pacific Ocean seawater data. We propose macroalgae is recording the influence of anthropogenic processes - in particular sewage sludge production and catalytic convertor exhaust - on the Os budget of Japanese waters. Therefore

  8. Attributing Atmospheric Methane to Anthropogenic Emission Sources.

    PubMed

    Allen, David

    2016-07-19

    Methane is a greenhouse gas, and increases in atmospheric methane concentration over the past 250 years have driven increased radiative forcing of the atmosphere. Increases in atmospheric methane concentration since 1750 account for approximately 17% of increases in radiative forcing of the atmosphere, and that percentage increases by approximately a factor of 2 if the effects of the greenhouse gases produced by the atmospheric reactions of methane are included in the assessment. Because of the role of methane emissions in radiative forcing of the atmosphere, the identification and quantification of sources of methane emissions is receiving increased scientific attention. Methane emission sources include biogenic, geogenic, and anthropogenic sources; the largest anthropogenic sources are natural gas and petroleum systems, enteric fermentation (livestock), landfills, coal mining, and manure management. While these source categories are well-known, there is significant uncertainty in the relative magnitudes of methane emissions from the various source categories. Further, the overall magnitude of methane emissions from all anthropogenic sources is actively debated, with estimates based on source sampling extrapolated to regional or national scale ("bottom-up analyses") differing from estimates that infer emissions based on ambient data ("top-down analyses") by 50% or more. To address the important problem of attribution of methane to specific sources, a variety of new analytical methods are being employed, including high time resolution and highly sensitive measurements of methane, methane isotopes, and other chemical species frequently associated with methane emissions, such as ethane. This Account describes the use of some of these emerging measurements, in both top-down and bottom-up methane emission studies. In addition, this Account describes how data from these new analytical methods can be used in conjunction with chemical mass balance (CMB) methods for source

  9. Role of oceanic circulation on contaminant lead distribution in the South Atlantic

    NASA Astrophysics Data System (ADS)

    Alleman, L. Y.; Church, T. M.; Ganguli, P.; Véron, A. J.; Hamelin, B.; Flegal, A. R.

    Both the relatively high lead concentrations and their characteristic anthropogenic isotopic compositions attest to the widespread contamination of industrial lead in the western Equatorial and South Atlantic Ocean. Spatial gradients in those isotopic signatures evidence the conservative lateral transport of lead in oceanic water masses, while the discrete isotopic signatures in deep oceanic waters substantiate the complementary hypothesis that the release of lead from settling particles is relatively small on a decadal time-scale. Specifically, the relatively low radiogenic lead (e.g., 206Pb/ 207Pb=1.148±0.009) in the Lower-North Atlantic Deep Water (l-NADW) south of 10° North is primarily attributed to US industrial lead emitted in the Northern Hemisphere prior to 1965, and the more radiogenic lead (e.g., 206Pb/ 207Pb=1.180±0.006) in the Upper-North Atlantic Deep Water (u-NADW) is primarily attributed to subsequent industrial lead emissions in that hemisphere. In contrast, the relatively radiogenic lead (e.g., 206Pb/ 207Pb=1.186±0.007) in the Antarctic Bottom Water (AABW) seemingly reflects a mixture of natural and anthropogenic lead sources within the Southern Hemisphere; and its isotopic dissimilarity with that (e.g., 206Pb/ 207Pb=1.159±0.002) of Antarctic Intermediate Water (AAIW) and the AABW may be due to differences in either their aeolian or water-mass inputs.

  10. World Input-Output Network

    PubMed Central

    Cerina, Federica; Zhu, Zhen; Chessa, Alessandro; Riccaboni, Massimo

    2015-01-01

    Production systems, traditionally analyzed as almost independent national systems, are increasingly connected on a global scale. Only recently becoming available, the World Input-Output Database (WIOD) is one of the first efforts to construct the global multi-regional input-output (GMRIO) tables. By viewing the world input-output system as an interdependent network where the nodes are the individual industries in different economies and the edges are the monetary goods flows between industries, we analyze respectively the global, regional, and local network properties of the so-called world input-output network (WION) and document its evolution over time. At global level, we find that the industries are highly but asymmetrically connected, which implies that micro shocks can lead to macro fluctuations. At regional level, we find that the world production is still operated nationally or at most regionally as the communities detected are either individual economies or geographically well defined regions. Finally, at local level, for each industry we compare the network-based measures with the traditional methods of backward linkages. We find that the network-based measures such as PageRank centrality and community coreness measure can give valuable insights into identifying the key industries. PMID:26222389

  11. Anthropogenic heavy metal signatures for the fast growing urban area of Natal (NE-Brazil)

    NASA Astrophysics Data System (ADS)

    Sindern, S.; Lima, R. F. S.; Schwarzbauer, J.; Petta, R. A.

    2007-04-01

    In this study the effect of anthropogenic discharges on the heavy metal content in the Potengi Jundiai river system near the fast growing city of Natal, NE-Brazil, is investigated. Due to the multiple anthropogenic source character without any predominating anthropogenic heavy metal discharge the area of Natal may serve as a characteristic place for the study of the impact of the fast growing Brazilian cities on the environment. In general the sediments of the Rio Potengi Jundiai river system in the studied area are not severely polluted. However, close to waste water drain pipes a characteristic anthropogenic heavy metal signature is visible in enhanced Zn, Pb, Cu and Cd values relative to reference elements such as Al and Fe. Sources are domestic and animal waste, combustion products and hydrocarbons. These heavy metals are probably mainly bound to organic matter. The elements Sn, Hg and Ag in part also belong to the anthropogenic heavy metal signature. The elements Cr, Ni and V are characteristic of weathering heavy minerals in crystalline rocks exposed in the catchment area of the river system and are not significantly added from anthropogenic sources. These heavy metals are most likely predominantly bound to oxides and represent the pristine geogenic background of the system. They can thus be used as reference elements to monitor incipient accumulation of Zn, Pb, Cu and Cd due to anthropogenic input. The element characteristics found here match with those found in other fast growing urban areas such as the Sao Paulo metropolitan area.

  12. Conservation implications of anthropogenic impacts on visual communication and camouflage.

    PubMed

    Delhey, Kaspar; Peters, Anne

    2017-02-01

    Anthropogenic environmental impacts can disrupt the sensory environment of animals and affect important processes from mate choice to predator avoidance. Currently, these effects are best understood for auditory and chemosensory modalities, and recent reviews highlight their importance for conservation. We examined how anthropogenic changes to the visual environment (ambient light, transmission, and backgrounds) affect visual communication and camouflage and considered the implications of these effects for conservation. Human changes to the visual environment can increase predation risk by affecting camouflage effectiveness, lead to maladaptive patterns of mate choice, and disrupt mutualistic interactions between pollinators and plants. Implications for conservation are particularly evident for disrupted camouflage due to its tight links with survival. The conservation importance of impaired visual communication is less documented. The effects of anthropogenic changes on visual communication and camouflage may be severe when they affect critical processes such as pollination or species recognition. However, when impaired mate choice does not lead to hybridization, the conservation consequences are less clear. We suggest that the demographic effects of human impacts on visual communication and camouflage will be particularly strong when human-induced modifications to the visual environment are evolutionarily novel (i.e., very different from natural variation); affected species and populations have low levels of intraspecific (genotypic and phenotypic) variation and behavioral, sensory, or physiological plasticity; and the processes affected are directly related to survival (camouflage), species recognition, or number of offspring produced, rather than offspring quality or attractiveness. Our findings suggest that anthropogenic effects on the visual environment may be of similar importance relative to conservation as anthropogenic effects on other sensory modalities

  13. Anthropogenic noise changes arthropod abundances.

    PubMed

    Bunkley, Jessie P; McClure, Christopher J W; Kawahara, Akito Y; Francis, Clinton D; Barber, Jesse R

    2017-05-01

    Anthropogenic noise is a widespread and growing form of sensory pollution associated with the expansion of human infrastructure. One specific source of constant and intense noise is that produced by compressors used for the extraction and transportation of natural gas. Terrestrial arthropods play a central role in many ecosystems, and given that numerous species rely upon airborne sounds and substrate-borne vibrations in their life histories, we predicted that increased background sound levels or the presence of compressor noise would influence their distributions. In the second largest natural gas field in the United States (San Juan Basin, New Mexico, USA), we assessed differences in the abundances of terrestrial arthropod families and community structure as a function of compressor noise and background sound level. Using pitfall traps, we simultaneously sampled five sites adjacent to well pads that possessed operating compressors, and five alternate, quieter well pad sites that lacked compressors, but were otherwise similar. We found a negative association between sites with compressor noise or higher levels of background sound and the abundance of five arthropod families and one genus, a positive relationship between loud sites and the abundance of one family, and no relationship between noise level or compressor presence and abundance for six families and two genera. Despite these changes, we found no evidence of community turnover as a function of background sound level or site type (compressor and noncompressor). Our results indicate that anthropogenic noise differentially affects the abundances of some arthropod families. These preliminary findings point to a need to determine the direct and indirect mechanisms driving these observed responses. Given the diverse and important ecological functions provided by arthropods, changes in abundances could have ecological implications. Therefore, we recommend the consideration of arthropods in the environmental

  14. Anthropogenic regulation of the phosphorus balance in the Thau catchment-coastal lagoon system (Mediterraean Sea, France) over 24 years.

    PubMed

    La Jeunesse, I; Elliott, M

    2004-04-01

    In the Thau lagoon, despite there being no phosphate limitation policy, the annual mean phosphate concentrations decreased by 90% between 1971 and 1994. The present study indicates a relationship between the decrease of phosphate concentrations and changes in urban, industrial and agricultural activities within the catchment generating phosphorus (P) inputs; and shellfish farming leading to phosphorus storage and export. The relationship (tonnes of P) is: P-PO(4)(3-) in the lagoon waters=1.0124 anthropogenic phosphorus balance--47.62 (r(2) = 0.824, p < 0.000). As population growth is expected in coastal zones, sustainable development requires the need for addressing the role played by human activities and the multi-scale regulation of them. As an element of integrated coastal zone management, the present study provides a regional scale analysis of these aspects.

  15. Anthropogenic impacts on Costa Rican bat parasitism are sex specific.

    PubMed

    Frank, Hannah K; Mendenhall, Chase D; Judson, Seth D; Daily, Gretchen C; Hadly, Elizabeth A

    2016-07-01

    While anthropogenic impacts on parasitism of wildlife are receiving growing attention, whether these impacts vary in a sex-specific manner remains little explored. Differences between the sexes in the effect of parasites, linked to anthropogenic activity, could lead to uneven sex ratios and higher population endangerment. We sampled 1108 individual bats in 18 different sites across an agricultural mosaic landscape in southern Costa Rica to investigate the relationships between anthropogenic impacts (deforestation and reductions in host species richness) and bat fly ectoparasitism of 35 species of Neotropical bats. Although female and male bat assemblages were similar across the deforestation gradient, bat fly assemblages tracked their hosts closely only on female bats. We found that in female hosts, parasite abundance per bat decreased with increasing bat species richness, while in male hosts, parasite abundance increased. We hypothesize the differences in the parasite-disturbance relationship are due to differences in roosting behavior between the sexes. We report a sex-specific parasite-disturbance relationship and argue that sex differences in anthropogenic impacts on wildlife parasitism could impact long-term population health and survival.

  16. WATERSHEED NUTRIENT INPUTS, PHYTOPLANKTON ACCUMULATION, AND C STOCKS IN CHESAPEAKE BAY

    EPA Science Inventory

    Inputs of N and P to Chesapeake Bay have been enhanced by anthropogenic activities. Fertilizers, developed areas, N emissions, and industrial effluents contribute to point and diffuse sources currently 2-20X higher than those from undisturbed watersheds. Enhanced nutrient inputs ...

  17. Natural Versus Anthropogenic Remediation of Streams Impacted by Acid Mine Drainage in Southeast Ohio

    NASA Astrophysics Data System (ADS)

    Clinton, T.; Lopez, D. L.

    2004-12-01

    Three streams that have been affected by acid mine drainage in southeast Ohio have been investigated (Sulphur Run in the Federal Creek watershed, Rock Run in the Monday Creek watershed, and Buffer Run in the Raccoon Creek watershed). Sulphur Run neutralizes acidic inputs naturally due to its strong buffering capacity acquired from water-rock interactions with the abundant carbonate lithology surrounding the stream. Rock Run and Buffer Run have been anthropogenically remediated using successive alkalinity producing wetlands, open limestone channels, and alkaline capping of adjacent coal refuse piles. The objective of this study is to compare the water quality evolution of the three streams. For this purpose, water and sediment samples were collected for chemical analysis and in-situ flow rate, alkalinity, acidity, pH, dissolved oxygen, and conductivity were measured. Preliminary results reveal that the pH of Sulphur Run, which never drops below 6.7, increases steadily along the flow path. Downstream of the remediation sites, the pH of Rock Run and Buffer Run is always below 4 and declines along the flow path, possibly due to a combination of additional acidic inputs downstream from the main source and the oxidation of metals, leading to hydrolysis reactions that produce additional hydrogen protons. The net alkalinity of Sulphur Run increases steadily downstream, reflecting the effectiveness of a continuous supply of alkaline material at neutralizing acidic inputs. Both Buffer Run and Rock Run are net acidic, suggesting that armoring of the open limestone channels by metal precipitates is impeding the recovery of water quality. The early results indicate that remediation schemes that do not mimic nature by providing a long term, steady supply of alkaline material appear to be ineffective.

  18. Continental anthropogenic primary particle number emissions

    NASA Astrophysics Data System (ADS)

    Paasonen, Pauli; Kupiainen, Kaarle; Klimont, Zbigniew; Visschedijk, Antoon; Denier van der Gon, Hugo A. C.; Amann, Markus

    2016-06-01

    Atmospheric aerosol particle number concentrations impact our climate and health in ways different from those of aerosol mass concentrations. However, the global, current and future anthropogenic particle number emissions and their size distributions are so far poorly known. In this article, we present the implementation of particle number emission factors and the related size distributions in the GAINS (Greenhouse Gas-Air Pollution Interactions and Synergies) model. This implementation allows for global estimates of particle number emissions under different future scenarios, consistent with emissions of other pollutants and greenhouse gases. In addition to determining the general particulate number emissions, we also describe a method to estimate the number size distributions of the emitted black carbon particles. The first results show that the sources dominating the particle number emissions are different to those dominating the mass emissions. The major global number source is road traffic, followed by residential combustion of biofuels and coal (especially in China, India and Africa), coke production (Russia and China), and industrial combustion and processes. The size distributions of emitted particles differ across the world, depending on the main sources: in regions dominated by traffic and industry, the number size distribution of emissions peaks in diameters range from 20 to 50 nm, whereas in regions with intensive biofuel combustion and/or agricultural waste burning, the emissions of particles with diameters around 100 nm are dominant. In the baseline (current legislation) scenario, the particle number emissions in Europe, Northern and Southern Americas, Australia, and China decrease until 2030, whereas especially for India, a strong increase is estimated. The results of this study provide input for modelling of the future changes in aerosol-cloud interactions as well as particle number related adverse health effects, e.g. in response to tightening

  19. Factors influencing anthropogenic carbon dioxide uptake in the North Atlantic in models of the ocean carbon cycle

    SciTech Connect

    Smith, R.S.; Marotzke, J.

    2008-09-30

    The uptake and storage of anthropogenic carbon in the North Atlantic is investigated using different configurations of ocean general circulation/carbon cycle models. We investigate how different representations of the ocean physics in the models, which represent the range of models currently in use, affect the evolution of CO{sub 2} uptake in the North Atlantic. The buffer effect of the ocean carbon system would be expected to reduce ocean CO{sub 2} uptake as the ocean absorbs increasing amounts of CO{sub 2}. We find that the strength of the buffer effect is very dependent on the model ocean state, as it affects both the magnitude and timing of the changes in uptake. The timescale over which uptake of CO{sub 2} in the North Atlantic drops to below preindustrial levels is particularly sensitive to the ocean state which sets the degree of buffering; it is less sensitive to the choice of atmospheric CO{sub 2} forcing scenario. Neglecting physical climate change effects, North Atlantic CO{sub 2} uptake drops below preindustrial levels between 50 and 300 years after stabilisation of atmospheric CO{sub 2} in different model configurations. Storage of anthropogenic carbon in the North Atlantic varies much less among the different model configurations, as differences in ocean transport of dissolved inorganic carbon and uptake of CO{sub 2} compensate each other. This supports the idea that measured inventories of anthropogenic carbon in the real ocean cannot be used to constrain the surface uptake. Including physical climate change effects reduces anthropogenic CO{sub 2} uptake and storage in the North Atlantic further, due to the combined effects of surface warming, increased freshwater input, and a slowdown of the meridional overturning circulation. The timescale over which North Atlantic CO{sub 2} uptake drops to below preindustrial levels is reduced by about one-third, leading to an estimate of this timescale for the real world of about 50 years after the stabilisation

  20. Input and Input Processing in Second Language Acquisition.

    ERIC Educational Resources Information Center

    Alcon, Eva

    1998-01-01

    Analyzes second-language learners' processing of linguistic data within the target language, focusing on input and intake in second-language acquisition and factors and cognitive processes that affect input processing. Input factors include input simplification, input enhancement, and interactional modifications. Individual learner differences…

  1. Anthropogenic Triggering of Large Earthquakes

    PubMed Central

    Mulargia, Francesco; Bizzarri, Andrea

    2014-01-01

    The physical mechanism of the anthropogenic triggering of large earthquakes on active faults is studied on the basis of experimental phenomenology, i.e., that earthquakes occur on active tectonic faults, that crustal stress values are those measured in situ and, on active faults, comply to the values of the stress drop measured for real earthquakes, that the static friction coefficients are those inferred on faults, and that the effective triggering stresses are those inferred for real earthquakes. Deriving the conditions for earthquake nucleation as a time-dependent solution of the Tresca-Von Mises criterion applied in the framework of poroelasticity yields that active faults can be triggered by fluid overpressures < 0.1 MPa. Comparing this with the deviatoric stresses at the depth of crustal hypocenters, which are of the order of 1–10 MPa, we find that injecting in the subsoil fluids at the pressures typical of oil and gas production and storage may trigger destructive earthquakes on active faults at a few tens of kilometers. Fluid pressure propagates as slow stress waves along geometric paths operating in a drained condition and can advance the natural occurrence of earthquakes by a substantial amount of time. Furthermore, it is illusory to control earthquake triggering by close monitoring of minor “foreshocks”, since the induction may occur with a delay up to several years. PMID:25156190

  2. Anthropogenic noise affects vocal interactions.

    PubMed

    McMullen, Heather; Schmidt, Rouven; Kunc, Hansjoerg P

    2014-03-01

    Animal communication plays a crucial role in many species, and it involves a sender producing a signal and a receiver responding to that signal. The shape of a signal is determined by selection pressures acting upon it. One factor that exerts selection on acoustic signals is the acoustic environment through which the signal is transmitted. Recent experimental studies clearly show that senders adjust their signals in response to increased levels of anthropogenic noise. However, to understand how noise affects the whole process of communication, it is vital to know how noise affects the receiver's response during vocal interactions. Therefore, we experimentally manipulated ambient noise levels to expose male European robins (Erithacus rubecula) to two playback treatments consisting of the same song: one with noise and another one without noise. We found that males responding to a conspecific in a noise polluted environment increased minimum frequency and decreased song complexity and song duration. Thus, we show that the whole process of communication is affected by noise, not just the behaviour of the sender.

  3. Anthropogenic triggering of large earthquakes.

    PubMed

    Mulargia, Francesco; Bizzarri, Andrea

    2014-08-26

    The physical mechanism of the anthropogenic triggering of large earthquakes on active faults is studied on the basis of experimental phenomenology, i.e., that earthquakes occur on active tectonic faults, that crustal stress values are those measured in situ and, on active faults, comply to the values of the stress drop measured for real earthquakes, that the static friction coefficients are those inferred on faults, and that the effective triggering stresses are those inferred for real earthquakes. Deriving the conditions for earthquake nucleation as a time-dependent solution of the Tresca-Von Mises criterion applied in the framework of poroelasticity yields that active faults can be triggered by fluid overpressures < 0.1 MPa. Comparing this with the deviatoric stresses at the depth of crustal hypocenters, which are of the order of 1-10 MPa, we find that injecting in the subsoil fluids at the pressures typical of oil and gas production and storage may trigger destructive earthquakes on active faults at a few tens of kilometers. Fluid pressure propagates as slow stress waves along geometric paths operating in a drained condition and can advance the natural occurrence of earthquakes by a substantial amount of time. Furthermore, it is illusory to control earthquake triggering by close monitoring of minor "foreshocks", since the induction may occur with a delay up to several years.

  4. How anthropogenic noise affects foraging.

    PubMed

    Luo, Jinhong; Siemers, Björn M; Koselj, Klemen

    2015-09-01

    The influence of human activity on the biosphere is increasing. While direct damage (e.g. habitat destruction) is relatively well understood, many activities affect wildlife in less apparent ways. Here, we investigate how anthropogenic noise impairs foraging, which has direct consequences for animal survival and reproductive success. Noise can disturb foraging via several mechanisms that may operate simultaneously, and thus, their effects could not be disentangled hitherto. We developed a diagnostic framework that can be applied to identify the potential mechanisms of disturbance in any species capable of detecting the noise. We tested this framework using Daubenton's bats, which find prey by echolocation. We found that traffic noise reduced foraging efficiency in most bats. Unexpectedly, this effect was present even if the playback noise did not overlap in frequency with the prey echoes. Neither overlapping noise nor nonoverlapping noise influenced the search effort required for a successful prey capture. Hence, noise did not mask prey echoes or reduce the attention of bats. Instead, noise acted as an aversive stimulus that caused avoidance response, thereby reducing foraging efficiency. We conclude that conservation policies may seriously underestimate numbers of species affected and the multilevel effects on animal fitness, if the mechanisms of disturbance are not considered.

  5. Anthropogenic impacts on the biogeochemistry and cycling of antimony.

    PubMed

    Shotyk, William; Krachler, Michael; Chen, Bin

    2005-01-01

    Antimony is a potentially toxic trace element with no known biological function. Antimony is commonly enriched in coals, and fossil fuel combustion appears to be the largest single source of anthropogenic Sb to the global atmosphere. Abundant in sulfide minerals, its emission to the atmosphere from anthropogenic activities is linked to the mining and metallurgy of non-ferrous metals, especially Pb, Cu, and Zn. In particular, the geochemical and mineralogical association of Sb with Pb minerals implies that, like Pb, Sb has been emitted to the environment for thousands of years because of Pb mining, smelting, and refining. In the US alone, there are more than 400 former secondary lead smelting operations and worldwide there are 133 Pb-Zn smelters in operation today. Antimony is used in creating and improving dozens of industrial and commercial materials including various alloys, ceramics, glasses, plastics, and synthetic fabrics, making waste incineration another important source of Sb to the environment. Enrichments of Sb in atmospheric aerosols, plants, soils, sediments, as well as alpine and polar snow and ice suggest that Sb contamination is extensive, but there are very few quantitative studies of the geographic extent, intensity, and chronology of this contamination. There is an urgent need to quantify the extent of human impacts and how these have changed with time. The decreasing inventories of anthropogenic Sb with time in peat cores from Switzerland and Scotland suggest that the atmospheric Sb flux may be declining, but there have been too few studies to make any general conclusions. In fact, some studies of sediments and biomonitors in central Europe show little decline in Sb concentrations during the past decades. There is an obvious need for reliable data from well dated archives such as polar snow and ice, peat bogs, and sediments. The air concentrations, extent of enrichment, particle size distribution, and rate of deposition of Sb in urban areas is

  6. Marine anthropogenic litter on British beaches: A 10-year nationwide assessment using citizen science data.

    PubMed

    Nelms, S E; Coombes, C; Foster, L C; Galloway, T S; Godley, B J; Lindeque, P K; Witt, M J

    2017-02-01

    Growing evidence suggests that anthropogenic litter, particularly plastic, represents a highly pervasive and persistent threat to global marine ecosystems. Multinational research is progressing to characterise its sources, distribution and abundance so that interventions aimed at reducing future inputs and clearing extant litter can be developed. Citizen science projects, whereby members of the public gather information, offer a low-cost method of collecting large volumes of data with considerable temporal and spatial coverage. Furthermore, such projects raise awareness of environmental issues and can lead to positive changes in behaviours and attitudes. We present data collected over a decade (2005-2014 inclusive) by Marine Conservation Society (MCS) volunteers during beach litter surveys carried along the British coastline, with the aim of increasing knowledge on the composition, spatial distribution and temporal trends of coastal debris. Unlike many citizen science projects, the MCS beach litter survey programme gathers information on the number of volunteers, duration of surveys and distances covered. This comprehensive information provides an opportunity to standardise data for variation in sampling effort among surveys, enhancing the value of outputs and robustness of findings. We found that plastic is the main constituent of anthropogenic litter on British beaches and the majority of traceable items originate from land-based sources, such as public littering. We identify the coast of the Western English Channel and Celtic Sea as experiencing the highest relative litter levels. Increasing trends over the 10-year time period were detected for a number of individual item categories, yet no statistically significant change in total (effort-corrected) litter was detected. We discuss the limitations of the dataset and make recommendations for future work. The study demonstrates the value of citizen science data in providing insights that would otherwise not be

  7. Input Decimated Ensembles

    NASA Technical Reports Server (NTRS)

    Tumer, Kagan; Oza, Nikunj C.; Clancy, Daniel (Technical Monitor)

    2001-01-01

    Using an ensemble of classifiers instead of a single classifier has been shown to improve generalization performance in many pattern recognition problems. However, the extent of such improvement depends greatly on the amount of correlation among the errors of the base classifiers. Therefore, reducing those correlations while keeping the classifiers' performance levels high is an important area of research. In this article, we explore input decimation (ID), a method which selects feature subsets for their ability to discriminate among the classes and uses them to decouple the base classifiers. We provide a summary of the theoretical benefits of correlation reduction, along with results of our method on two underwater sonar data sets, three benchmarks from the Probenl/UCI repositories, and two synthetic data sets. The results indicate that input decimated ensembles (IDEs) outperform ensembles whose base classifiers use all the input features; randomly selected subsets of features; and features created using principal components analysis, on a wide range of domains.

  8. Background determination of element and anthropogenic compounds in soils of the Maryland coastal plain

    SciTech Connect

    Nemeth, G.R.; Romano, D.J.; Smegal, D.; Paul, J.

    1996-12-31

    Background concentrations of elements and anthropogenic compounds in soil were determined for the coastal plain region of the northern Chesapeake Bay in the vicinity of a major military facility. Soils used to establish background are from off-site locations. Lead and octachlorodibenzodioxin were determined to be anthropogenic regional contaminants. The background concentrations of arsenic, beryllium, and manganese exceed Region III Environmental Protection Agency risk based criteria for residential soils.

  9. Increased anthropogenic pressure decreases species richness in tropical intertidal reefs.

    PubMed

    Portugal, Adriana Brizon; Carvalho, Fabrício Lopes; de Macedo Carneiro, Pedro Bastos; Rossi, Sergio; de Oliveira Soares, Marcelo

    2016-09-01

    Multiple human stressors affect tropical intertidal sandstone reefs, but little is known about their biodiversity and the environmental impacts of these stressors. In the present study, multiple anthropogenic pressures were integrated using the relative environmental pressure index (REPI) and related to benthic community structure across an intertidal gradient in five sandstone reefs in the tropical South Atlantic coast. Greater species richness and diversity were noted in the low intertidal zones. There was a negative relationship between REPI and species richness, suggesting that increasing anthropogenic pressure has decreased benthic richness. The factors associated with the loss of richness were jetties built to control erosion, urban areas, beachfront kiosks and restaurants, fish markets, and storm sewers with illegal sewage connections. Our results highlight the need for better infrastructure planning and rigorous monitoring of coastal urban areas, since the large influence of multiple human pressures in these reefs leads to biodiversity losses.

  10. Chemical oceanography. Increasing anthropogenic nitrogen in the North Pacific Ocean.

    PubMed

    Kim, Il-Nam; Lee, Kitack; Gruber, Nicolas; Karl, David M; Bullister, John L; Yang, Simon; Kim, Tae-Wook

    2014-11-28

    The recent increase in anthropogenic emissions of reactive nitrogen from northeastern Asia and the subsequent enhanced deposition over the extensive regions of the North Pacific Ocean (NPO) have led to a detectable increase in the nitrate (N) concentration of the upper ocean. The rate of increase of excess N relative to phosphate (P) was found to be highest (~0.24 micromoles per kilogram per year) in the vicinity of the Asian source continent, with rates decreasing eastward across the NPO, consistent with the magnitude and distribution of atmospheric nitrogen deposition. This anthropogenically driven increase in the N content of the upper NPO may enhance primary production in this N-limited region, potentially leading to a long-term change of the NPO from being N-limited to P-limited. Copyright © 2014, American Association for the Advancement of Science.

  11. Changes in South Pacific anthropogenic carbon

    NASA Astrophysics Data System (ADS)

    Waters, Jason F.; Millero, Frank J.; Sabine, Christopher L.

    2011-12-01

    The changes in anthropogenic CO2 are evaluated in the South Pacific, along the meridional line P18 (110°W) and the zonal line P06 (32°S), using the extended multiple linear regression (eMLR) method. The structure of the column inventory of anthropogenic CO2 on P18 is similar to the southern section of P16 in the central South Pacific (150°W), but the overall increase is greater by approximately 5-10 μmol kg-1. The value of the anthropogenic CO2 inventory on P18 is in agreement at the crossover point of an earlier evaluation of P06. Subsequent changes in pH due to the increase in anthropogenic CO2 are also evaluated. The change in pH is determined from the changes in anthropogenic CO2 and do not reflect variability in other decadal signals. For both cruise tracks, the average annual change in pH is -0.0016 mol kg-1 yr-1. This value is in good agreement with the average decrease in pH in the North Pacific, at the Hawaii Times Series and the subtropical North Atlantic. The uptake rates of anthropogenic CO2 are within reasonable agreement with similar studies in the South Pacific. There is evidence for greater uptake of anthropogenic CO2 in the western South Pacific and is attributed to the formation of subtropical Mode Water in the region.

  12. An Inverse Modeling Approach to Investigate Past Lead Atmospheric Deposition in Southern Greenland

    NASA Astrophysics Data System (ADS)

    Massa, C.; Monna, F.; Bichet, V.; Gauthier, E.; Richard, H.

    2013-12-01

    The aim of this study is to model atmospheric pollution lead fluxes using two different paleoenvironmental records, covering the last 2000 years, located in southern Greenland. Fifty five sediment samples from the Lake Igaliku sequence (61°00.403'N, 45°26.494'W) were analyzed for their Pb and Al contents, and for lead isotopic compositions. The second archive consists in a previously published dataset (Shotyk et al., 2003), including Zr and Pb concentrations, and lead isotopic compositions, obtained from a minerogenic peat deposit located 16 km northwest of Lake Igaliku (61°08.314'N, 45°33.703'W). As natural background concentrations are high and obliterate most of the airborne anthropogenic lead, it is not possible to isolate this anthropogenic contribution through time with classical methods (i.e. Pb is normalized to a lithogenic and conservative element). Moreover, the background 206Pb/207Pb ratio is rather noisy because of the wide geological heterogeneity of sediment sources, which further complicated unambiguous detection of the lead pollution. To overcome these difficulties, an inverse modeling approach based on assumptions about past lead inputs was applied. This method consists of simulating a range of anthropogenic fluxes to determine the best match between measured and simulated data, both for Pb concentrations and isotopic compositions. The model is validated by the coherence of the results obtained from the two independent datasets that must reflect a similar pollution history. Although notable 206Pb/207Pb ratio shifts suggest that the first signs of anthropogenic inputs may have occurred in the 15th century, the signal-to-noise ratio was too low to significantly influence the sediment composition. Nevertheless we were able to estimate that anthropogenic lead fluxes did not exceed 2700 μg m-2 yr-1, a maximum value recorded during the 1960s. The comparison with other records from the North Atlantic Islands reveals a spatial gradient most likely due

  13. Anthropogenic mercury emissions in China

    NASA Astrophysics Data System (ADS)

    Streets, David G.; Hao, Jiming; Wu, Ye; Jiang, Jingkun; Chan, Melissa; Tian, Hezhong; Feng, Xinbin

    An inventory of mercury emissions from anthropogenic activities in China is compiled for the year 1999 from official statistical data. We estimate that China's emissions were 536 (±236) t of total mercury. This value includes open biomass burning, but does not include natural sources or re-emission of previously deposited mercury. Approximately 45% of the Hg comes from non-ferrous metals smelting, 38% from coal combustion, and 17% from miscellaneous activities, of which battery and fluorescent lamp production and cement production are the largest. Emissions are heaviest in Liaoning and Guangdong Provinces, where extensive smelting occurs, and in Guizhou Province, where there is much small-scale combustion of high-Hg coal without emission control devices. Emissions are gridded at 30×30 min spatial resolution. We estimate that 56% of the Hg in China is released as Hg 0, 32% as Hg 2+, and 12% as Hg p. Particulate mercury emissions are high in China due to heavy burning of coal in residential and small industrial settings without PM controls. Emissions of Hg 2+ from coal-fired power plants are high due to the absence of flue-gas desulfurization units, which tend to dissolve the soluble divalent mercury. Metals smelting operations favor the production of elemental mercury. Much of the Hg is released from small-scale activities in rather remote areas, and therefore the activity levels are quite uncertain. Also, emissions test data for Chinese sources are lacking, causing uncertainties in Hg emission factors and removal efficiencies. Overall, we calculate an uncertainty level of ±44% (95% confidence interval) in the estimate of total emissions. We recommend field testing of coal combustors and smelters in China to improve the accuracy of these estimates.

  14. The contemporary anthropogenic chromium cycle.

    PubMed

    Johnson, Jeremiah; Schewel, Laura; Graedel, T E

    2006-11-15

    Chromium is an essential engineering metal used in stainless and alloy steels, chemicals, and refractory products. Using material flow analysis, all major anthropogenic chromium flows are characterized for the year 2000, from mining through discard, on three spatial levels: fifty-four countries, nine world regions, and the planet. Included is the first detailed quantification of chromium in internationally traded finished products and diverse waste streams. Findings include (1) 78% of chromium flow entering final use is added as a net addition to stock on the global level; most countries are close to this figure; (2) the majority of mining occurs in Africa (2400 Gg Cr/yr) and the Commonwealth of Independent States (1090 Gg Cr/yr), while the major end-users are Asia, Europe, and North America at 1150, 1140, and 751 Gg Cr/yr, respectively; (3) waste flows of chromium are the greatest in Europe (420 Gg Cr/yr), Asia (370 Gg Cr/yr), and North America (290 Gg Cr/yr), but the composition of these waste flows varies greatly among the world regions; (4) releases of chromium by the global system, which total 2630 Gg Cr/yr, are nearly evenly divided among tailings, ferrochromium slag, downgraded scrap, and post-consumer losses; (5) many countries have a heavy foreign dependence on chromium in the all forms, as is demonstrated for the United States. The findings relating to in-use stock changes and finished product trade are relevant to industry, allowing for more accurate planning for future scrap availability. The quantification of releases due to discards and dissipation hold environmental and human health relevance, while the full life cycle international trade assessment addresses local scarcity.

  15. Atmospheric trace metal inputs in the Misten bog (East Belgium): Special attention to sampling techniques and site-spatial variability.

    NASA Astrophysics Data System (ADS)

    Allan, Mohammed; Fagel, Nathalie; de Vleeschouwer, François; Mattielli, Nadine; Piotrowska, Natalia; Sikorski, Jarek; Sonke, Jeroen E.; Le Roux, Gaël.

    2010-05-01

    Peat bogs have a great potential to record anthropogenic inputs via their constituting mosses, because they draw their nutrients only from the atmosphere. These atmospheric inputs can be studied thanks to geochemical characteristics such as trace metal concentrations. Coupling lead isotopes to elemental geochemistry allows one to decipher between natural (erosion of rocks) and anthropogenic (pollution due to industrial development, vehicles...) inputs. The purpose of our work was to study the pollution history of trace metals in the region of Misten (Belgium) at a local and a regional level, and to place modern industrial pollution in this region in a wider historical perspective. Four peat cores (01W, 04W, 05W and 06W) were collected in 2008 in the Misten bog (Hautes-Fagnes plateau, E-Belgium) and studied for their trace metal and lead isotopic signatures. Analyses were accompanied by coupled 210Pb-14C age models in order to estimate the mercury and lead accumulation rates in each core and compare them to other European records. The Hg record was compared to the various anthropogenic sources as determined by Pb isotopes. The Hg concentration profiles resemble those of Pb, an element known to be immobile in peatlands. The correlation between these two metals suggests a predominant anthropogenic source of Hg (and Pb). In the W06 core, low and stable Hg accumulation rates (0.9-3.1 μg m-2 yr-1) are found in the lower layers (503-1823AD). High Hg accumulation rates are found in the surface and sub-surface layers (post-1823AD) and peak at 123.3 μg m-2 yr-1 (1969AD). In 01W, the lead enrichment factor (Pb E.F.) coupled with the continuous drop in 206Pb/204Pb, 207Pb/204Pb, 208Pb/204Pb isotopic ratios since 539 AD until 1973AD indicates the growing importance of the non-radiogenic Pb released from anthropogenic activities. The highest concentrations of Pb (613-662 µg g-1) have been found near the surface of the bog dated between 1902 and 1954AD. The Pb E.F. also

  16. Multidisciplinary study on anthropogenic landslides in Nepal

    NASA Astrophysics Data System (ADS)

    Puglia, Christopher; Derron, Marc-Henri; Nicolet, Pierrick; Sudmeier-Rieux, Karen; Jaboyedoff, Michel; Devkota, Sanjay

    2013-04-01

    Nepal is a country in which shallow landslide is a frequent phenomenon. Monsoon is the main triggering factor but anthropogenic influence is often significant too. Indeed, many infrastructures, such as roads or water pipes, are not built in a rigorous way because of a lack of funds and knowledge. In the present study we examine the technical, social and economic issues of landslide management for two sites in Nepal. The first site is located in Sanusiruwari VDC (Sindhupalchock district, central Nepal) and the second one in Namadi VDC (Ramecchap district, central Nepal). Both sites are affected by landslides induced by the construction of hydropower plants. These landslides may threaten the viability of the hydropower plants. At both sites the problems are quite similar, but the first site project is a private one and the second one is a public one implemented by the United Nations Development Programme (UNDP). For both sites, bioengineering methods using Vetiver (Vetyveria zizanioides) plantations is the main stabilization measure. To follow the progression of both landslides, fieldwork observations were conducted before and after the 2012 rainy season, including photogrammetric and distancemeter acquisitions. Main issues were discussed with communities and stakeholders of the hydropower projects through interviews and participatory risk mapping. Main issues include: lack of communication between the project managers and communities leading to conflict and the lack of maintenance of the bio-engineering sites, leading to less effective Vetiver growth and slope stabilization. Comparing the landslide management (technical, social and economic) of the two projects allows to point out some specific issues within an integrated risk perspective.

  17. A seasonal cycle of terrestrial inputs in Lake Van, Turkey.

    PubMed

    Huguet, C; Fietz, S; Moraleda, N; Litt, T; Heumann, G; Stockhecke, M; Anselmetti, F S; Sturm, M

    2012-09-01

    Lake Van in Turkey is the world's largest soda lake (607 km(3)). The lake's catchment area is estimated to be ∼12,500 km(2), and the terrestrial input is carried through eolian, riverine, snowmelt and anthropogenic paths. Extent and seasonality of the terrestrial inputs to the lake have not been studied, but it is essential to evaluate its environmental status and to assess the use of environmental proxies to estimate the lake's response to climate changes. This study aims to measure seasonal changes in terrestrial input of natural and anthropogenic origin as recorded by the fluxes of pollen and biomarkers of soil bacteria and vascular or higher plants, as well as petrogenic biomarkers in monthly resolved sediment traps from August 2006 to July 2007. Fluxes of pollen, soil and higher plant biomarkers seem to be related to precipitation and snowmelt in autumn and spring. In addition, dust storms, which are common during the summer months, may have resulted in long-distance transport. Anthropogenic biomarker fluxes indicate year-round petrogenic contamination although some mature biomarker fluxes are higher in summer and in late winter-spring. The relative changes between petrogenic markers indicate variations in the pollutant sources.

  18. Development of a national anthropogenic heating database with an extrapolation for international cities

    NASA Astrophysics Data System (ADS)

    Sailor, David J.; Georgescu, Matei; Milne, Jeffrey M.; Hart, Melissa A.

    2015-10-01

    Given increasing utility of numerical models to examine urban impacts on meteorology and climate, there exists an urgent need for accurate representation of seasonally and diurnally varying anthropogenic heating data, an important component of the urban energy budget for cities across the world. Incorporation of anthropogenic heating data as inputs to existing climate modeling systems has direct societal implications ranging from improved prediction of energy demand to health assessment, but such data are lacking for most cities. To address this deficiency we have applied a standardized procedure to develop a national database of seasonally and diurnally varying anthropogenic heating profiles for 61 of the largest cities in the United Stated (U.S.). Recognizing the importance of spatial scale, the anthropogenic heating database developed includes the city scale and the accompanying greater metropolitan area. Our analysis reveals that a single profile function can adequately represent anthropogenic heating during summer but two profile functions are required in winter, one for warm climate cities and another for cold climate cities. On average, although anthropogenic heating is 40% larger in winter than summer, the electricity sector contribution peaks during summer and is smallest in winter. Because such data are similarly required for international cities where urban climate assessments are also ongoing, we have made a simple adjustment accounting for different international energy consumption rates relative to the U.S. to generate seasonally and diurnally varying anthropogenic heating profiles for a range of global cities. The methodological approach presented here is flexible and straightforwardly applicable to cities not modeled because of presently unavailable data. Because of the anticipated increase in global urban populations for many decades to come, characterizing this fundamental aspect of the urban environment - anthropogenic heating - is an essential

  19. Transboundary atmospheric lead pollution.

    PubMed

    Erel, Yigal; Axelrod, Tamar; Veron, Alain; Mahrer, Yitzak; Katsafados, Petros; Dayan, Uri

    2002-08-01

    A high-temporal resolution collection technique was applied to refine aerosol sampling in Jerusalem, Israel. Using stable lead isotopes, lead concentrations, synoptic data, and atmospheric modeling, we demonstrate that lead detected in the atmosphere of Jerusalem is not only anthropogenic lead of local origin but also lead emitted in other countries. Fifty-seven percent of the collected samples contained a nontrivial fraction of foreign atmospheric lead and had 206Pb/207Pb values which deviated from the local petrol-lead value (206Pb/207Pb = 1.113) by more than two standard deviations (0.016). Foreign 206Pb/207Pb values were recorded in Jerusalem on several occasions. The synoptic conditions on these dates and reported values of the isotopic composition of lead emitted in various countries around Israel suggest that the foreign lead was transported to Jerusalem from Egypt, Turkey, and East Europe. The average concentration of foreign atmospheric lead in Jerusalem was 23 +/- 17 ng/m3, similar to the average concentration of local atmospheric lead, 21 +/- 18 ng/ m3. Hence, the load of foreign atmospheric lead is similar to the load of local atmospheric lead in Jerusalem.

  20. Contaminated lead environments of man: reviewing the lead isotopic evidence in sediments, peat, and soils for the temporal and spatial patterns of atmospheric lead pollution in Sweden.

    PubMed

    Bindler, Richard

    2011-08-01

    Clair Patterson and colleagues demonstrated already four decades ago that the lead cycle was greatly altered on a global scale by humans. Moreover, this change occurred long before the implementation of monitoring programs designed to study lead and other trace metals. Patterson and colleagues also developed stable lead isotope analyses as a tool to differentiate between natural and pollution-derived lead. Since then, stable isotope analyses of sediment, peat, herbaria collections, soils, and forest plants have given us new insights into lead biogeochemical cycling in space and time. Three important conclusions from our studies of lead in the Swedish environment conducted over the past 15 years, which are well supported by extensive results from elsewhere in Europe and in North America, are: (1) lead deposition rates at sites removed from major point sources during the twentieth century were about 1,000 times higher than natural background deposition rates a few thousand years ago (~10 mg Pb m(-2) year(-1) vs. 0.01 mg Pb m(-2) year(-1)), and even today (~1 mg Pb m(-2) year(-1)) are still almost 100 times greater than natural rates. This increase from natural background to maximum fluxes is similar to estimated changes in body burdens of lead from ancient times to the twentieth century. (2) Stable lead isotopes ((206)Pb/(207)Pb ratios shown in this paper) are an effective tool to distinguish anthropogenic lead from the natural lead present in sediments, peat, and soils for both the majority of sites receiving diffuse inputs from long range and regional sources and for sites in close proximity to point sources. In sediments >3,500 years and in the parent soil material of the C-horizon, (206)Pb/(207)Pb ratios are higher, 1.3 to >2.0, whereas pollution sources and surface soils and peat have lower ratios that have been in the range 1.14-1.18. (3) Using stable lead isotopes, we have estimated that in southern Sweden the cumulative anthropogenic burden of

  1. Effects of Nitrogen Inputs and Watershed Characteristics on ...

    EPA Pesticide Factsheets

    Nitrogen (N) inputs to the landscape have been linked previously to N loads exported from watersheds at the national scale; however, stream N concentration is arguably more relevant than N load for drinking water quality, freshwater biological responses and establishment of nutrient criteria. In this study, we combine national-scale anthropogenic N input data, including synthetic fertilizer, crop biological N fixation, manure applied to farmland, atmospheric N deposition, and point source inputs, with data from the 2008-09 National Rivers and Streams Assessment to quantify the relationship between N inputs and in-stream concentrations of total N (TN), dissolved inorganic N (DIN), and total organic N (TON) (calculated as TN – DIN). In conjunction with simple linear regression, we use multiple regression to understand how watershed and stream reach attributes modify the effect of N inputs on N concentrations. Median TN was 0.50 mg N L-1 with a maximum of 25.8 mg N L-1. Total N inputs to the watershed ranged from less than 1 to 196 kg N ha-1 y-1, with a median of 14.4 kg N ha-1 y-1. Atmospheric N deposition was the single largest anthropogenic N source in the majority of sites, but, agricultural sources generally dominate total N inputs in sites with elevated N concentrations. The sum of all N inputs were positively correlated with concentrations of all forms of N [r2 = 0.44, 0.43, and 0.18 for TN, DIN, and TON, respectively (all log-transformed), n = 1112], indi

  2. Late Holocene climate: Natural or anthropogenic?

    NASA Astrophysics Data System (ADS)

    Ruddiman, W. F.; Fuller, D. Q.; Kutzbach, J. E.; Tzedakis, P. C.; Kaplan, J. O.; Ellis, E. C.; Vavrus, S. J.; Roberts, C. N.; Fyfe, R.; He, F.; Lemmen, C.; Woodbridge, J.

    2016-03-01

    For more than a decade, scientists have argued about the warmth of the current interglaciation. Was the warmth of the preindustrial late Holocene natural in origin, the result of orbital changes that had not yet driven the system into a new glacial state? Or was it in considerable degree the result of humans intervening in the climate system through greenhouse gas emissions from early agriculture? Here we summarize new evidence that moves this debate forward by testing both hypotheses. By comparing late Holocene responses to those that occurred during previous interglaciations (in section 2), we assess whether the late Holocene responses look different (and thus anthropogenic) or similar (and thus natural). This comparison reveals anomalous (anthropogenic) signals. In section 3, we review paleoecological and archaeological syntheses that provide ground truth evidence on early anthropogenic releases of greenhouse gases. The available data document large early anthropogenic emissions consistent with the anthropogenic ice core anomalies, but more information is needed to constrain their size. A final section compares natural and anthropogenic interpretations of the δ13C trend in ice core CO2.

  3. NET ANTHROPOGENIC PHOSPHORUS INPUTS; SPATIAL AND TEMPORAL VARIABILITY IN THE CHESAPEAKE BAY REGION

    EPA Science Inventory

    Coastal watershed eutrophication has increasingly become a regional and global issue as larger proportions of the earth’s human population settle in coastal areas. Human activities on the land have severely impacted the water resources of the Chesapeake Bay, one of the world’s l...

  4. Biogeochemical responses to nutrient inputs in a Cuban coastal lagoon: runoff, anthropogenic, and groundwater sources.

    PubMed

    González-De Zayas, R; Merino-Ibarra, M; Soto-Jiménez, M F; Castillo-Sandoval, F S

    2013-12-01

    Laguna Larga, a coastal lagoon in central Cuba, has been heavily altered by tourism infrastructure construction and sewage disposal. We hypothesize that this has decreased the circulation and caused eutrophication of the lagoon. To assess this, 12 bimonthly samplings were carried out in 2007-2008. Temperature, salinity, oxygen, nutrients and nitrogen, and phosphorous fractions (inorganic, organic, and total) were determined. Water and salt budgets, as well as biogeochemical fluxes of nitrogen and phosphorus were calculated using the LOICZ budget model for the three sections of the lagoon identified by morphological constrains and salinity patterns. Laguna Larga is a choked lagoon with restricted water circulation, low exchange, and high residence times that vary significantly along its sections. Residence time was estimated to be 0.1-0.7 years for the inner section and 1-9 days for the outer one. High levels of total nitrogen (annual means 126-137 μM, peaks up to 475 μM) and phosphorus (2.5-4.4 μM, peaks up to 14.5 μM) are evidence of eutrophication of Laguna Larga. During 2007, an average precipitation year, Laguna Larga exported water (703 m(3) d(-1)) and was a source of nitrogen (9.026 mmol m(-2) d(-1)) and phosphorus (0.112 mmol m(-2) d(-1)) to the adjacent sea. δ(15)N determinations in the seagrass Thalassia testudinum (-1.83 to +3.02 ‰) differed significantly between sites in the lagoon and offshore reference sites located W of the inlet, but were similar to those located E of the inlet. δ(15)N determinations in the seaweed Penicillus dumetosus (+1.02 to +4.2) did not show significant differences.

  5. How inhibiting nitrification affects nitrogen cycle and reduces environmental impacts of anthropogenic nitrogen input

    EPA Science Inventory

    We conducted a meta-analysis of 103 nitrification inhibitor (NI) studies, and evaluated how NI application affects crop productivity and other ecosystem services in agricultural systems. Our results showed that, compared to conventional fertilizer practice, applications of NI alo...

  6. NET ANTHROPOGENIC PHOSPHORUS INPUTS; SPATIAL AND TEMPORAL VARIABILITY IN THE CHESAPEAKE BAY REGION

    EPA Science Inventory

    Coastal watershed eutrophication has increasingly become a regional and global issue as larger proportions of the earth’s human population settle in coastal areas. Human activities on the land have severely impacted the water resources of the Chesapeake Bay, one of the world’s l...

  7. How inhibiting nitrification affects nitrogen cycle and reduces environmental impacts of anthropogenic nitrogen input

    EPA Science Inventory

    We conducted a meta-analysis of 103 nitrification inhibitor (NI) studies, and evaluated how NI application affects crop productivity and other ecosystem services in agricultural systems. Our results showed that, compared to conventional fertilizer practice, applications of NI alo...

  8. New classification of landslide-inducing anthropogenic activities

    NASA Astrophysics Data System (ADS)

    Michoud, C.; Jaboyedoff, M.; Derron, M.-H.; Nadim, F.; Leroi, E.

    2012-04-01

    Although landslides are usually considered typical examples of natural hazards, they can be influenced by human activities. Many examples can be found in the literature about slope instabilities induced by anthropogenic activities, ranging from small superficial landslides to rock avalanches. Research on this topic is of primary importance for understanding and mitigation of landslide risk. Indeed, slope stabilities influenced by human actions contribute significantly to the risk level because, by definition, they are located where elements at risk and people are present. Within the framework of the European project SafeLand "Living with Landslide Risk in Europe", the authors analyzed the landslides induced by anthropogenic factors in Europe and elsewhere (SafeLand deliverable D1.6). During the bibliographical research, it appeared that a complete and illustrated classification on human activities influencing slope stabilities does not yet exist. Therefore, a new classification was introduced by Michoud et al. (2011) about anthropogenic activities affecting slope stability conditions. This classification takes into account conceptual processes leading to landslides (Terzaghi, 1950; Jaboyedoff and Derron, 2005) and the distinction between destabilization factors and triggering factors (Vaunat et al., 1994; Leroueil et al., 1996). The classification was tested and improved through fifty-eight well-documented case studies, even lots of large landslides, such as Elm, Aberfan, Namsos and Rissa landslides, etc. Furthermore, the boundary between natural and "anthropogenic" landslide triggers (e.g. water run-off modified by new land-uses, creating landslides some km farther), and the time during which changes and reactions are to be considered as direct consequences of human activities were highlighted. Finally, anthropogenic influences can also be positive and examples of (non-voluntary) positive human impacts on slope stability are presented. Jaboyedoff, M. and Derron, M

  9. Stable nitrogen isotopes in coastal macroalgae: geographic and anthropogenic variability.

    PubMed

    Viana, Inés G; Bode, Antonio

    2013-01-15

    Growing human population adds to the natural nitrogen loads to coastal waters. Both anthropogenic and natural nitrogen is readily incorporated in new biomass, and these different nitrogen sources may be traced by the measurement of the ratio of stable nitrogen isotopes (δ(15)N). In this study δ(15)N was determined in two species of macroalgae (Ascophyllum nodosum and Fucus vesiculosus), and in nitrate and ammonium to determine the relative importance of anthropogenic versus natural sources of nitrogen along the coast of NW Spain. Both algal species and nitrogen sources showed similar isotopic enrichment for a given site, but algal δ(15)N was not related to either inorganic nitrogen concentrations or δ(15)N in the water samples. The latter suggests that inorganic nitrogen inputs are variable and do not always leave an isotopic trace in macroalgae. However, a significant linear decrease in macroalgal δ(15)N along the coast is consistent with the differential effect of upwelling. Besides this geographic variability, the influence of anthropogenic nitrogen sources is evidenced by higher δ(15)N in macroalgae from rias and estuaries compared to those from open coastal areas and in areas with more than 15×10(3) inhabitants in the watershed. These results indicate that, in contrast with other studies, macroalgal δ(15)N is not simply related to either inorganic nitrogen concentrations or human population size but depends on other factors as the upwelling or the efficiency of local waste treatment systems. Copyright © 2012 Elsevier B.V. All rights reserved.

  10. Sinks as integrative elements of the anthropogenic metabolism

    NASA Astrophysics Data System (ADS)

    Kral, Ulrich; Brunner, Paul H.

    2015-04-01

    The anthropogenic metabolism is an open system requiring exchange of materials and energy between the anthroposphere and the environment. Material and energy flows are taken from nature and become utilized by men. After utilization, the materials either remain in the anthroposphere as recycling products, or they leave the anthroposphere as waste and emission flows. To accommodate these materials without jeopardizing human and environmental health, limited natural sinks are available; thus, man-made sinks have to be provided where natural sinks are missing or overloaded. The oral presentation (1) suggests a coherent definition of the term "sink", encompassing natural and man-made processes, (2) presents a framework to analyse and evaluate anthropogenic material flows to sinks, based on the tool substance flow analysis and impact assessment methodology, and (3) applies the framework in a case study approach for selected substances such as Copper and Lead in Vienna and Perfluorooctane sulfonate in Switzerland. Finally, the numeric results are aggregated in terms of a new indicator that specifies on a regional scale which fractions of anthropogenic material flows to sinks are acceptable. The following results are obtained: In Vienna, 99% of Cu flows to natural and man-made sinks are in accordance with accepted standards. However, the 0.7% of Cu entering urban soils and the 0.3% entering receiving waters surpass the acceptable level. In the case of Pb, 92% of all flows into sinks prove to be acceptable, but 8% are disposed of in local landfills with limited capacity. For PFOS, 96% of all flows into sinks are acceptable. 4% cannot be evaluated due to a lack of normative criteria, despite posing a risk for human health and the environment. The case studies corroborate the need and constraints of sinks to accommodate inevitable anthropogenic material flows.

  11. The GEIA global gridded inventory of anthropogenic VOCs

    SciTech Connect

    Benkovitz, C.M.; Berdowski, J.J.M.; Veldt, C.

    1995-04-01

    Modeling assessments of the atmospheric chemistry, air quality and climatic conditions of the past, present and future require as input inventories of emissions of the appropriate chemical species constructed on appropriate spatial and temporal scales. The task of the Global Emissions Inventories Activity (GEIA) of the International Global Atmospheric Chemistry Project (IGAC) is the production of global inventories suitable for a range of research applications. Current GEIA programs are generally based on addressing emissions by species; an international working group of interested participants cooperates in the work needed to compile each inventory. The work of the GEIA program addressing the compilation of a global inventory of anthropogenic emissions of Volatile Organic Compounds (VOCs) gridded with 1{degree} resolution is presented. Past studies were used to identify anthropogenic activities according to their contribution to global VOC emissions, based on results of these initial studies, activity and species groupings for emissions reporting have been selected. Current status of the work of the committee is discussed. Detailed information on available activity rates, emission factors, and speciation profiles for each defined sector is being compiled. Links to investigators working on the compilation of VOC emissions on a regional level have been established.

  12. Anthropogenic sources stimulate resonance of a natural rock bridge

    NASA Astrophysics Data System (ADS)

    Moore, Jeffrey R.; Thorne, Michael S.; Koper, Keith D.; Wood, John R.; Goddard, Kyler; Burlacu, Relu; Doyle, Sarah; Stanfield, Erik; White, Benjamin

    2016-09-01

    The natural modes of vibration of bedrock landforms, as well as the sources and effects of stimulated resonance remain poorly understood. Here we show that seismic energy created by an induced earthquake and an artificial reservoir has spectral content coincident with the natural modes of vibration of a prominent rock bridge. We measured the resonant frequencies of Rainbow Bridge, Utah using data from two broadband seismometers placed on the span, and identified eight distinct vibrational modes between 1 and 6 Hz. A distant, induced earthquake produced local ground motion rich in 1 Hz energy, stimulating a 20 dB increase in measured power at the bridge's fundamental mode. Moreover, we establish that wave action on Lake Powell, an artificial reservoir, generates microseismic energy with peak power ~1 Hz, also exciting resonance of Rainbow Bridge. These anthropogenic sources represent relatively new energy input for the bridge with unknown consequences for structural fatigue.

  13. High spatiotemporal variability in meiofaunal assemblages in Blanes Canyon (NW Mediterranean) subject to anthropogenic and natural disturbances

    NASA Astrophysics Data System (ADS)

    Román, Sara; Vanreusel, Ann; Romano, Chiara; Ingels, Jeroen; Puig, Pere; Company, Joan B.; Martin, Daniel

    2016-11-01

    We investigated the natural and anthropogenic drivers controlling the spatiotemporal distribution of the meiofauna in the submarine Blanes Canyon, and its adjacent western slope (NW Mediterranean margin of the Iberian Peninsula). We analyzed the relationships between the main sedimentary environmental variables (i.e. grain size, Chl-a, Chl-a: phaeopigments, CPE, organic carbon and total nitrogen) and the density and structure of the meiofaunal assemblages along a bathymetric gradient (from 500 to 2000 m depth) in spring and autumn of 2012 and 2013. Twenty-one and 16 major taxa were identified for respectively the canyon and slope, where the assemblages were always dominated by nematodes. The gradual decreasing meiofaunal densities with increasing depth at the slope showed little variability among stations and corresponded with a uniform pattern of food availability. The canyon was environmentally much more variable and sediments contained greater amounts of food resources (Chl-a and CPE) throughout, leading not only to increased meiofaunal densities compared to the slope, but also different assemblages in terms of composition and structure. This variability in the canyon is only partly explained by seasonal food inputs. The high densities found at 900 m and 1200 m depth coincided with significant increases in food availability compared to shallower and deeper stations in the canyon. Our results suggest that the disruption in expected bathymetric decrease in densities at 900-1200 m water depth coincided with noticeable changes in the environmental variables typical for disturbance and deposition events (e.g., higher sand content and CPE), evoking the hypothesis of an anthropogenic effect at these depths in the canyon. The increased downward particle fluxes at 900-1200 m depth caused by bottom trawling along canyon flanks, as reported in previous studies, support our hypothesis and allude to a substantial anthropogenic factor influencing benthic assemblages at these

  14. Engineering paradigms and anthropogenic global change

    NASA Astrophysics Data System (ADS)

    Bohle, Martin

    2016-04-01

    This essay discusses 'paradigms' as means to conceive anthropogenic global change. Humankind alters earth-systems because of the number of people, the patterns of consumption of resources, and the alterations of environments. This process of anthropogenic global change is a composite consisting of societal (in the 'noosphere') and natural (in the 'bio-geosphere') features. Engineering intercedes these features; e.g. observing stratospheric ozone depletion has led to understanding it as a collateral artefact of a particular set of engineering choices. Beyond any specific use-case, engineering works have a common function; e.g. civil-engineering intersects economic activity and geosphere. People conceive their actions in the noosphere including giving purpose to their engineering. The 'noosphere' is the ensemble of social, cultural or political concepts ('shared subjective mental insights') of people. Among people's concepts are the paradigms how to shape environments, production systems and consumption patterns given their societal preferences. In that context, engineering is a means to implement a given development path. Four paradigms currently are distinguishable how to make anthropogenic global change happening. Among the 'engineering paradigms' for anthropogenic global change, 'adaptation' is a paradigm for a business-as-usual scenario and steady development paths of societies. Applying this paradigm implies to forecast the change to come, to appropriately design engineering works, and to maintain as far as possible the current production and consumption patterns. An alternative would be to adjust incrementally development paths of societies, namely to 'dovetail' anthropogenic and natural fluxes of matter and energy. To apply that paradigm research has to identify 'natural boundaries', how to modify production and consumption patterns, and how to tackle process in the noosphere to render alterations of common development paths acceptable. A further alternative

  15. Record temperature streak bears anthropogenic fingerprint

    NASA Astrophysics Data System (ADS)

    Mann, Michael E.; Miller, Sonya K.; Rahmstorf, Stefan; Steinman, Byron A.; Tingley, Martin

    2017-08-01

    We use a previously developed semiempirical approach to assess the likelihood of the sequence of consecutive record-breaking temperatures in 2014-2016. This approach combines information from historical temperature data and state-of-the-art historical climate model simulations from the Coupled Model Intercomparison Project Phase 5 (CMIP5). We find that this sequence of record-breaking temperatures had a negligible (<0.03%) likelihood of occurrence in the absence of anthropogenic warming. It was still a rare but not implausible event (roughly 1-3% likelihood) taking anthropogenic warming into effect. The probability that three consecutive records would have been observed at some point since 2000 is estimated as 30-50% given anthropogenic warming and <0.7% in its absence. The likelihood of observing the specific level of record warmth recorded during 2016 is no more than one-in-a-million neglecting anthropogenic warming, but as high as 27%, i.e., a nearly one-in-three chance of occurrence taking anthropogenic warming into account.

  16. Anthropogenic noise affects behavior across sensory modalities.

    PubMed

    Kunc, Hansjoerg P; Lyons, Gillian N; Sigwart, Julia D; McLaughlin, Kirsty E; Houghton, Jonathan D R

    2014-10-01

    Many species are currently experiencing anthropogenically driven environmental changes. Among these changes, increasing noise levels are specifically a problem for species using acoustic signals (i.e., species relying on signals that use the same sensory modality as anthropogenic noise). Yet many species use other sensory modalities, such as visual and olfactory signals, to communicate. However, we have only little understanding of whether changes in the acoustic environment affect species that use sensory modalities other than acoustic signals. We studied the impact of anthropogenic noise on the common cuttlefish Sepia officinalis, which uses highly complex visual signals. We showed that cuttlefish adjusted their visual displays by changing their color more frequently during a playback of anthropogenic noise, compared with before and after the playback. Our results provide experimental evidence that anthropogenic noise has a marked effect on the behavior of species that are not reliant on acoustic communication. Thus, interference in one sensory channel, in this case the acoustic one, affects signaling in other sensory channels. By considering sensory channels in isolation, we risk overlooking the broader implications of environmental changes for the behavior of animals.

  17. Aquatic environmental changes and anthropogenic activities reflected by the sedimentary records of the Shima River, Southern China.

    PubMed

    Gao, Lei; Wang, Zhuowei; Shan, Jiju; Chen, Jianyao; Tang, Changyuan; Yi, Ming

    2017-03-08

    Reconstructing historical sedimentary records is essential for better understanding the effects of anthropogenic activities on river environments. We used lead-210 to date riverine sediment core from the Shima River in China. We obtained a sedimentary history of 34 years (1982-2015) for core S2, which had a length of 34 cm. The sedimentation rate of 0.304-2.04 cm y(-1) was controlled by both flood events and anthropogenic activities. The conservative element content depth profiles remained relatively constant, suggestive of a relatively stable sediment provenance; therefore, the increase in the sedimentation rate over time was mainly the result of domestic and industrial wastewater effluent and the construction of a rubber dam at the middle and lower reach of the Shima River. From 1982 to 2015, the nutrient and trace metal depth profiles could be divided in three periods based on their trends. From 1982 to 1993, the vertical profiles of nutrients (organic carbon, total phosphorus, and total nitrogen) and three trace metals (nickel, zinc, and manganese) were relatively stable; however, the gradual decrease in copper and cadmium was likely associated with a reduction in agricultural chemical application. From 1993 to 2003, a population explosion and rapid industrialization were responsible for an increase in the input of pollutants into the Shima River, which was partly attenuated by water from the Dong River, leading to a gradual increase in nutrient and trace metal contents. Finally, from 2003 to 2015, the Shima River stopped being used as a source of water due to its deteriorating water quality. The relatively lower velocity of the water flow after the recovery of its flow direction and the reconstruction of the rubber dam in 2009 provided advantageous sedimentary conditions, promoting nutrient accumulation and significant trace metal enrichment.

  18. Spatial Distribution of Lead in Sacramento, California, USA

    PubMed Central

    Solt, Michael J.; Deocampo, Daniel M.; Norris, Michelle

    2015-01-01

    Chronic exposure to lead remains a health concern in many urban areas; Sacramento, California is one example, with state surveillance data showing nearly 3% of screened children reported with blood lead levels over 4.5 μg/dL in 2009. To investigate the environmental exposure, 91 soil samples were collected and analyzed by ICP-AES and ICP-MS for 14 elements. An additional 28 samples were collected from areas of focus and analyzed by hand-held X-ray fluorescence spectrometry for Pb and Zn. Analysis of the metals data revealed non-normal distributions and positive skewness, consistent with anthropogenic input. In addition, high correlation coefficients (≥0.75) of metal concentrations in Cd-Pb, Cd-Zn, Pb-Zn, and Sb-Sn pairs suggest similarities in the input mechanisms. Semivariograms generated from Pb and associated metals reveal these metals to exhibit spatial correlation. A prediction map of lead concentrations in soil was generated by ordinary kriging, showing elevated concentrations in soil located in the central, older area of Sacramento where historic traffic density and industrial activity have been historically concentrated. XRF analysis of Pb and Zn from additional samples verifies elevated concentrations in the central areas of Sacramento as predicted. PMID:25789455

  19. 21st Century Rise in Anthropogenic Nitrogen on a South China Sea Coral Reef

    NASA Astrophysics Data System (ADS)

    Ren, H. A.; Chen, Y. C.; Wang, X. T.; Wong, G. T. F.; Cohen, A. L.; Sigman, D. M.

    2016-12-01

    With the rapid rise in pollution-associated nitrogen inputs to the western Pacific, it has been suggested that even the open ocean has been impacted. In a coral core from Dongsha Island, an atoll 340 km from shore, we observe a decline in the 15N/14N of coral skeleton-bound organic matter, which is best explained by increased deposition of anthropogenic atmospheric N on the open ocean and its incorporation into plankton and the atoll corals. The decrease began just before 2000 CE, decades later than other work would have suggested, and the amplitude of decline suggest that anthropogenic atmospheric N input is now 15% of the upward mixing of natural subsurface nitrate in this region, a third to a half of the percentage estimated by models and nutrient ratio analyses.

  20. 21st-century rise in anthropogenic nitrogen deposition on a remote coral reef

    NASA Astrophysics Data System (ADS)

    Ren, Haojia; Chen, Yi-Chi; Wang, Xingchen T.; Wong, George T. F.; Cohen, Anne L.; DeCarlo, Thomas M.; Weigand, Mira A.; Mii, Horng-Sheng; Sigman, Daniel M.

    2017-05-01

    With the rapid rise in pollution-associated nitrogen inputs to the western Pacific, it has been suggested that even the open ocean has been affected. In a coral core from Dongsha Atoll, a remote coral reef ecosystem, we observe a decline in the 15N/14N of coral skeleton-bound organic matter, which signals increased deposition of anthropogenic atmospheric N on the open ocean and its incorporation into plankton and, in turn, the atoll corals. The first clear change occurred just before 2000 CE, decades later than predicted by other work. The amplitude of change suggests that, by 2010, anthropogenic atmospheric N deposition represented 20 ± 5% of the annual N input to the surface ocean in this region, which appears to be at the lower end of other estimates.

  1. Anthropogenic emissions of carbon monoxide.

    PubMed

    Horner, J M

    2000-01-01

    Carbon monoxide (CO) is a colorless, nonirritating, odorless and tasteless gas. Carbon monoxide combines with hemoglobin far more readily than does oxygen, leading to tissue hypoxia. Thousands of people die annually from CO poisoning, and those recovering from acute exposure commonly suffer brain damage. Chronic poisoning is of particular concern to sufferers of coronary heart disease, pregnant women, and people with certain hematological disorders. Indoor emission sources, notably fuel-burning heating appliances, cause most unintentional deaths and cases of illness and should be the main focus of concern. Motor vehicle emissions pose a chronic health risk for occupationally exposed groups. Smoking is a major source of personal exposure. Recent exposure to CO is commonly evaluated by measuring blood carboxyhemoglobin levels, which are related to the concentration of atmospheric CO. Monitoring methods are reviewed here, and monitoring is considered in relation to air quality standards and guidelines. Finally, control measures for motor vehicles and indoor heating appliances are suggested.

  2. Isolating the anthropogenic component of Arctic warming

    SciTech Connect

    Chylek, Petr; Hengartner, Nicholas; Lesins, Glen; Klett, James D.; Humlum, Ole; Wyatt, Marcia; Dubey, Manvendra K.

    2014-05-28

    Structural equation modeling is used in statistical applications as both confirmatory and exploratory modeling to test models and to suggest the most plausible explanation for a relationship between the independent and the dependent variables. Although structural analysis cannot prove causation, it can suggest the most plausible set of factors that influence the observed variable. Here, we apply structural model analysis to the annual mean Arctic surface air temperature from 1900 to 2012 to find the most effective set of predictors and to isolate the anthropogenic component of the recent Arctic warming by subtracting the effects of natural forcing and variability from the observed temperature. We also find that anthropogenic greenhouse gases and aerosols radiative forcing and the Atlantic Multidecadal Oscillation internal mode dominate Arctic temperature variability. Finally, our structural model analysis of observational data suggests that about half of the recent Arctic warming of 0.64 K/decade may have anthropogenic causes.

  3. Isolating the anthropogenic component of Arctic warming

    DOE PAGES

    Chylek, Petr; Hengartner, Nicholas; Lesins, Glen; ...

    2014-05-28

    Structural equation modeling is used in statistical applications as both confirmatory and exploratory modeling to test models and to suggest the most plausible explanation for a relationship between the independent and the dependent variables. Although structural analysis cannot prove causation, it can suggest the most plausible set of factors that influence the observed variable. Here, we apply structural model analysis to the annual mean Arctic surface air temperature from 1900 to 2012 to find the most effective set of predictors and to isolate the anthropogenic component of the recent Arctic warming by subtracting the effects of natural forcing and variabilitymore » from the observed temperature. We also find that anthropogenic greenhouse gases and aerosols radiative forcing and the Atlantic Multidecadal Oscillation internal mode dominate Arctic temperature variability. Finally, our structural model analysis of observational data suggests that about half of the recent Arctic warming of 0.64 K/decade may have anthropogenic causes.« less

  4. Isolating the anthropogenic component of Arctic warming

    NASA Astrophysics Data System (ADS)

    Chylek, Petr; Hengartner, Nicholas; Lesins, Glen; Klett, James D.; Humlum, Ole; Wyatt, Marcia; Dubey, Manvendra K.

    2014-05-01

    Structural equation modeling is used in statistical applications as both confirmatory and exploratory modeling to test models and to suggest the most plausible explanation for a relationship between the independent and the dependent variables. Although structural analysis cannot prove causation, it can suggest the most plausible set of factors that influence the observed variable. We apply structural model analysis to the annual mean Arctic surface air temperature from 1900 to 2012 to find the most effective set of predictors and to isolate the anthropogenic component of the recent Arctic warming by subtracting the effects of natural forcing and variability from the observed temperature. We find that anthropogenic greenhouse gases and aerosols radiative forcing and the Atlantic Multidecadal Oscillation internal mode dominate Arctic temperature variability. Our structural model analysis of observational data suggests that about half of the recent Arctic warming of 0.64 K/decade may have anthropogenic causes.

  5. Emergent anthropogenic trends in California Current upwelling

    NASA Astrophysics Data System (ADS)

    Brady, Riley X.; Alexander, Michael A.; Lovenduski, Nicole S.; Rykaczewski, Ryan R.

    2017-05-01

    Upwelling in the California Current System (CCS) sustains a productive ecosystem and is mediated by alongshore, equatorward wind stress. A decades-old hypothesis proposes that global warming will accelerate these upwelling favorable winds. Recent analyses provide empirical support for upwelling intensification in the poleward portion of the CCS. However, these studies rely on proxies for upwelling and are limited in their ability to distinguish anthropogenic forcing from internal climate variability. Here we estimate simulated changes in CCS upwelling from 1920 to 2100 using monthly output from a single climate model ensemble, where divergences among simulations can be attributed entirely to internal climate variability. Our projections suggest that CCS upwelling will become more intense in the spring and less intense in the summer as a result of anthropogenic climate change. Anthropogenic changes in upwelling will emerge primarily in the second half of the century.

  6. TASSRAP Input Module

    DTIC Science & Technology

    1977-07-29

    retrieve data necessary for the other modules to function. Initially there are 13 inputs, with the CRT dis - playing the information to be entered...id 46aý .0sso somma % 4bt--f. ft Aa W #4t - lQ *a - 4 c ,0 45 40 aK 43 ’ C = 04 ZSC 0 de *020.4 %- li’l ~ ~ ~ ~ ~ ~ & 1&.1 gol~ -,.-’ ow. -6 -N*4••1L...tv Z (𔃽 - C- ft %- ftb 0*4 *- -1 *4* (30 w ag &h 𔃾 0 a _6a .N I 0 A. 6.2 IL ILN ’ S MS 6C 0 to ~ 0 " di a S 0 m J *- -j f’ md op9 -9 $-. -6 = -A U .Af

  7. LEADING WITH LEADING INDICATORS

    SciTech Connect

    PREVETTE, S.S.

    2005-01-27

    This paper documents Fluor Hanford's use of Leading Indicators, management leadership, and statistical methodology in order to improve safe performance of work. By applying these methods, Fluor Hanford achieved a significant reduction in injury rates in 2003 and 2004, and the improvement continues today. The integration of data, leadership, and teamwork pays off with improved safety performance and credibility with the customer. The use of Statistical Process Control, Pareto Charts, and Systems Thinking and their effect on management decisions and employee involvement are discussed. Included are practical examples of choosing leading indicators. A statistically based color coded dashboard presentation system methodology is provided. These tools, management theories and methods, coupled with involved leadership and employee efforts, directly led to significant improvements in worker safety and health, and environmental protection and restoration at one of the nation's largest nuclear cleanup sites.

  8. The Oceanic Sink for Anthropogenic CO2

    SciTech Connect

    Sabine, Chris; Feely, R. A.; Gruber, N.; Key, Robert; Lee, K.; Bullister, J.L.; Wanninkhof, R.; Wong, C. S.; Wallace, D.W.R.; Tilbrook, B.; Millero, F. J.; Peng, T.-H.; Kozyr, Alexander; Ono, Tsueno

    2004-01-01

    Using inorganic carbon measurements from an international survey effort in the 1990s and a tracer-based separation technique, we estimate a global oceanic anthropogenic carbon dioxide (CO2) sink for the period from 1800 to 1994 of 118 19 petagrams of carbon. The oceanic sink accounts for ~48% of the total fossil-fuel and cement-manufacturing emissions, implying that the terrestrial biosphere was a net source of CO2 to the atmosphere of about 39 28 petagrams of carbon for this period. The current fraction of total anthropogenic CO2 emissions stored in the ocean appears to be about one-third of the long-term potential.

  9. The oceanic sink for anthropogenic CO2.

    PubMed

    Sabine, Christopher L; Feely, Richard A; Gruber, Nicolas; Key, Robert M; Lee, Kitack; Bullister, John L; Wanninkhof, Rik; Wong, C S; Wallace, Douglas W R; Tilbrook, Bronte; Millero, Frank J; Peng, Tsung-Hung; Kozyr, Alexander; Ono, Tsueno; Rios, Aida F

    2004-07-16

    Using inorganic carbon measurements from an international survey effort in the 1990s and a tracer-based separation technique, we estimate a global oceanic anthropogenic carbon dioxide (CO2) sink for the period from 1800 to 1994 of 118 +/- 19 petagrams of carbon. The oceanic sink accounts for approximately 48% of the total fossil-fuel and cement-manufacturing emissions, implying that the terrestrial biosphere was a net source of CO2 to the atmosphere of about 39 +/- 28 petagrams of carbon for this period. The current fraction of total anthropogenic CO2 emissions stored in the ocean appears to be about one-third of the long-term potential.

  10. Improved representation of stratocumulus clouds and the anthropogenic aerosol effect

    NASA Astrophysics Data System (ADS)

    Neubauer, David; Lohmann, Ulrike; Hoose, Corinna; Frontoso, Grazia M.

    2014-05-01

    Stratocumulus clouds are important for future climate predictions as they have a strong cooling effect and the feedback of low clouds is believed to be a major cause of the model spread in climate sensitivity. Stratocumulus clouds are difficult to represent in a general circulation model because of their small vertical extent. Stratocumulus regions are also areas of a strong anthropogenic aerosol effect. Simulations of the anthropogenic aerosol effect can be expected to depend on the representation of stratocumulus clouds in climate models. We address the representation of several of the physical processes that have to be accounted for when modeling stratocumuli in the general circulation model ECHAM6 (Stevens et al., 2013) coupled to the aerosol module HAM2 (Zhang et al., 2012). As a 'long tail' stability function can lead to excessive mixing at high stabilities we replaced it with a 'sharp' stability function. The stratocumulus cloud cover and liquid water path increase, similar to previous studies, with the 'sharp' stability function in ECHAM6-HAM2. We also study the impact of increased vertical resolution in the lower troposphere in ECHAM6-HAM2 on stratocumulus clouds. First results show improvements for the cloud height and thickness with increased vertical resolution. To simulate a realistic mixing state and size of particles released by evaporation of clouds and precipitation we include aerosol processing in stratiform clouds. First results from multi-year simulations show that using a 'sharp' stability function decreases the anthropogenic aerosol effect from -1.5 W/m2 to -1.2 W/m2 and in-cloud aerosol processing to -0.8 W/m2. This strong decrease is due to an increase in the background aerosol load. Increased vertical resolution doesn't seem to affect the anthropogenic aerosol effect in the global average. Further results on the impact of changing the vertical resolution, a different stability function and in-cloud aerosol processing in ECHAM6-HAM2 on the

  11. Chronology of anthropogenic impacts reconstructed from sediment records of trace metals and Pb isotopes in Todos os Santos Bay (NE Brazil).

    PubMed

    Andrade, R L B; Hatje, V; Masqué, P; Zurbrick, C M; Boyle, E A; Santos, W P C

    2017-08-08

    The evolution of the impacts of anthropogenic activities in Todos os Santos Bay was evaluated by profiles of trace metals and Pb isotopes determined in sediment cores. Fluxes of metals increased up to 12, 4 and 2 times for Cu, Pb, and Zn, respectively, compared to those recorded in the beginning of the 20(th) century. Stable Pb isotopes identified a decommissioned lead smelter and burning of fossil fuels as the main sources of Pb. Most metals showed minor to moderate enrichment factors (EF<4), but Cu and Pb were highly enriched (EF=28 and 6, respectively) at the Aratu harbor. Temporal changes in sediments were associated to different activities, namely Pb smelting, burning of fossil fuels, maritime traffic, petroleum related activities, inputs of domestic effluents, and changes in land uses. The effects of the implementation of environmental policies to improve the waters of the bay could not be identified in the evaluated cores. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. Uptake and storage of anthropogenic CO2 in the pacific ocean estimated using two modeling approaches

    NASA Astrophysics Data System (ADS)

    Li, Yangchun; Xu, Yongfu

    2012-07-01

    A basin-wide ocean general circulation model (OGCM) of the Pacific Ocean is employed to estimate the uptake and storage of anthropogenic CO2 using two different simulation approaches. The simulation (named BIO) makes use of a carbon model with biological processes and full thermodynamic equations to calculate surface water partial pressure of CO2, whereas the other simulation (named PTB) makes use of a perturbation approach to calculate surface water partial pressure of anthropogenic CO2. The results from the two simulations agree well with the estimates based on observation data in most important aspects of the vertical distribution as well as the total inventory of anthropogenic carbon. The storage of anthropogenic carbon from BIO is closer to the observation-based estimate than that from PTB. The Revelle factor in 1994 obtained in BIO is generally larger than that obtained in PTB in the whole Pacific, except for the subtropical South Pacific. This, to large extent, leads to the difference in the surface anthropogenic CO2 concentration between the two runs. The relative difference in the annual uptake between the two runs is almost constant during the integration processes after 1850. This is probably not caused by dissolved inorganic carbon (DIC), but rather by a factor independent of time. In both runs, the rate of change in anthropogenic CO2 fluxes with time is consistent with the rate of change in the growth rate of atmospheric partial pressure of CO2.

  13. Modeling and generating input processes

    SciTech Connect

    Johnson, M.E.

    1987-01-01

    This tutorial paper provides information relevant to the selection and generation of stochastic inputs to simulation studies. The primary area considered is multivariate but much of the philosophy at least is relevant to univariate inputs as well. 14 refs.

  14. Input Multiplicities in Process Control.

    ERIC Educational Resources Information Center

    Koppel, Lowell B.

    1983-01-01

    Describes research investigating potential effect of input multiplicity on multivariable chemical process control systems. Several simple processes are shown to exhibit the possibility of theoretical developments on input multiplicity and closely related phenomena are discussed. (JN)

  15. Redox reactions and weak buffering capacity lead to acidification in the Chesapeake Bay.

    PubMed

    Cai, Wei-Jun; Huang, Wei-Jen; Luther, George W; Pierrot, Denis; Li, Ming; Testa, Jeremy; Xue, Ming; Joesoef, Andrew; Mann, Roger; Brodeur, Jean; Xu, Yuan-Yuan; Chen, Baoshan; Hussain, Najid; Waldbusser, George G; Cornwell, Jeffrey; Kemp, W Michael

    2017-08-28

    The combined effects of anthropogenic and biological CO2 inputs may lead to more rapid acidification in coastal waters compared to the open ocean. It is less clear, however, how redox reactions would contribute to acidification. Here we report estuarine acidification dynamics based on oxygen, hydrogen sulfide (H2S), pH, dissolved inorganic carbon and total alkalinity data from the Chesapeake Bay, where anthropogenic nutrient inputs have led to eutrophication, hypoxia and anoxia, and low pH. We show that a pH minimum occurs in mid-depths where acids are generated as a result of H2S oxidation in waters mixed upward from the anoxic depths. Our analyses also suggest a large synergistic effect from river-ocean mixing, global and local atmospheric CO2 uptake, and CO2 and acid production from respiration and other redox reactions. Together they lead to a poor acid buffering capacity, severe acidification and increased carbonate mineral dissolution in the USA's largest estuary.The potential contribution of redox reactions to acidification in coastal waters is unclear. Here, using measurements from the Chesapeake Bay, the authors show that pH minimum occurs at mid-depths where acids are produced via hydrogen sulfide oxidation in waters mixed upward from anoxic depths.

  16. The atmospheric lead record preserved in lagoon sediments at a remote equatorial Pacific location: Palmyra Atoll, northern Line Islands.

    PubMed

    Collen, John D; Baker, Joel A; Dunbar, Robert B; Rieser, Uwe; Gardner, Jonathan P; Garton, David W; Christiansen, Kylie J

    2011-02-01

    Anthropogenic lead (Pb) inputs to the atmosphere increased greatly over the past century and now dominate Pb supply to the oceans. However, the Pb content of sediments across the equatorial Pacific region is relatively unknown, and data exist only for deep sea sites where Pb deposition lags surface water inputs by up to a century. Here we present ICP-MS analyses of Pb of a core from a lagoon at Palmyra Atoll, northern Line Islands, that spans approximately the past 160 years. The non-bioturbated sediments of the euxinic lagoon, coupled with rapid rates of deposition, provide a unique fine-scale record of atmospheric Pb supply at a remote Pacific location. These first observations of historic Pb sedimentation in an atoll lagoon reveal a 63-fold increase in Pb flux to sediments during the past century and correlate directly with the North American consumption of leaded gasoline that began in 1926.

  17. Lead in the environment

    USGS Publications Warehouse

    Pattee, O.H.; Pain, D.J.; Hoffman, David J.; Rattner, Barnett A.; Burton, G. Allen; Cairns, John=

    2003-01-01

    Anthropogenic uses of lead have probably altered its availability and environmental distribution more than any other toxic element. Consequently, lead concentrations in many living organisms may be approaching thresholds of toxicity for the adverse effects of lead. Such thresholds are difficult to define, as they vary with the chemical and physical form of lead, exposure regime, other elements present and also vary both within and between species. The technological capability to accurately quantify low lead concentrations has increased over the last decade, and physiological and behavioral effects have been measured in wildlife with tissue lead concentrations below those previously considered safe for humans.s.236 Consequently. lead criteria for the protection of wildlife and human health are frequently under review, and 'thresholds' of lead toxicity are being reconsidered. Proposed lead criteria for the protection of natural resources have been reviewed by Eisler. Uptake of lead by plants is limited by its generally low availability in soils and sediments, and toxicity may be limited by storage mechanisms and its apparently limited translocation within most plants. Lead does not generally accumulate within the foliar parts of plants, which limits its transfer to higher trophic levels. Although lead may concentrate in plant and animal tissues, no evidence of biomagnification exists. Acid deposition onto surface waters and soils with low buffering capacity may influence the availability of lead for uptake by plants and animals, and this may merit investigation at susceptible sites. The biological significance of chronic low-level lead exposure to wildlife is sometimes difficult to quantify. Animals living in urban environments or near point sources of lead emission are inevitably subject to greater exposure to lead and enhanced risk of lead poisoning. Increasingly strict controls on lead emissions in many countries have reduced exposure to lead from some sources

  18. Lead Speciation in Microorganisms.

    PubMed

    Stewart, Theodora J

    2017-04-10

    The biogeochemical cycles of lead (Pb) have been largely affected by anthropogenic activities as a result of its high natural abundance and use over the centuries [1]. At sites more strongly impacted by urbanization [2] and mining [3], Pb is found at high nano to low micromolar concentrations in surface waters, and can be significantly higher in soil and sediment [4]. Microorganisms are found everywhere and their responses to Pb exposure can range from resistant to highly sensitive [5, 6]. These varying levels of toxicity can be attributed to the cellular handling of Pb, making it important to understand the role of intracellular Pb speciation for more accurate toxicity predictions.

  19. Acid lakes from natural and anthropogenic causes

    SciTech Connect

    Patrick, R.; Binetti, V.P.; Halterman, S.G.

    1981-01-30

    Lakes may be acid because of natural ecological conditions or because of anthropogenic activities. Apparently there has been a recent increase in acidity of many lakes in the northeastern United States. Factors that may be contributing to this increase include the use by utilities of precipitators, sulfur scrubbers, and tall stacks; the use of petroleum; and methods of combustion of fossil fuels.

  20. Physiological implications of anthropogenic environmental calcium depletion

    Treesearch

    Catherine H. Borer; Paul G. Schaberg; Donald H. DeHayes; Gary J. Hawley

    2001-01-01

    Recent evidence indicates that numerous anthropogenic factors can deplete calcium (Ca) from forested ecosystems. Although it is difficult to quantify the extent of this depletion, some reports indicate that the magnitude of Ca losses may be substantial. The potential for Ca depletion raises important questions about tree health. Only a fraction of foliar Ca is...

  1. Anthropogenic iron oxide aerosols enhance atmospheric heating

    PubMed Central

    Moteki, Nobuhiro; Adachi, Kouji; Ohata, Sho; Yoshida, Atsushi; Harigaya, Tomoo; Koike, Makoto; Kondo, Yutaka

    2017-01-01

    Combustion-induced carbonaceous aerosols, particularly black carbon (BC) and brown carbon (BrC), have been largely considered as the only significant anthropogenic contributors to shortwave atmospheric heating. Natural iron oxide (FeOx) has been recognized as an important contributor, but the potential contribution of anthropogenic FeOx is unknown. In this study, we quantify the abundance of FeOx over East Asia through aircraft measurements using a modified single-particle soot photometer. The majority of airborne FeOx particles in the continental outflows are of anthropogenic origin in the form of aggregated magnetite nanoparticles. The shortwave absorbing powers (Pabs) attributable to FeOx and to BC are calculated on the basis of their size-resolved mass concentrations and the mean Pabs(FeOx)/Pabs(BC) ratio in the continental outflows is estimated to be at least 4–7%. We demonstrate that in addition to carbonaceous aerosols the aggregate of magnetite nanoparticles is a significant anthropogenic contributor to shortwave atmospheric heating. PMID:28508863

  2. Estimation of Anthropogenic Heat Emissions in Delhi, India and Their Role in Urban Heat Island Effect

    NASA Astrophysics Data System (ADS)

    Bhati, S.; Mohan, M.

    2016-12-01

    Energy consumption in the urban environment impacts the urban surface energy budget and leads to the emission of anthropogenic sensible heat into the atmosphere. Anthropogenic heat (AH) can vary both in time and space, and are not readily measured. In present study, anthropogenic heat emissions have been estimated using an inventory approach for Delhi. The main sources that have been considered are electricity consumption, vehicular emissions, fuel consumption in domestic sector and waste heat from power plants. Total estimated anthropogenic heat is apportioned gridwise (2 km2) and incorporated in the WRF (version 3.5) model coupled with single-layer Urban canopy model (UCM) to assess the impact of these emissions on urban heat island effect in Delhi. Vehicular emissions have been found to be highest contributor to anthropogenic heat emissions (47%) followed by electricity consumption (28%), domestic fuel consumption (16%) and waste heat from power plants (9%). Highest annual average anthropogenic heat flux was estimated to be 25.2 Wm-2. High flux zones are observed in east Delhi and densely occupied and commercial zones of Sitaram Bazar and Connaught Place. Inclusion of anthropogenic heat emissions in the model improves model performance for near surface temperature as well as urban heat island intensities. Maximum simulated night-time UHI improves from 5.95°C (without AH) to 6.24°C (with AH) against observed value of 6.68°C, thereby indicating positive contribution of anthropogenic heat emissions along with urban canopy towards UHI effect in Delhi. Similarly, spatial distribution and UHI hotspots are found to be comparatively closer to corresponding observed distribution and hotspots with anthropogenic heat emissions being added to the WRF model. Overall, relatively improved model performance is indicative of the impact of anthropogenic heat emissions in local urban meteorology and urban heat island effect in Delhi. Hence, rising population and change in land

  3. Anthropogenic phosphorus flow analysis of Hefei City, China.

    PubMed

    Li, Sisi; Yuan, Zengwei; Bi, Jun; Wu, Huijun

    2010-11-01

    The substance flow analysis (SFA) method was employed to examine phosphorus flow and its connection to water pollution in the city of Hefei, China, in 2008. As human activity is the driving force of phosphorus flux from the environment to the economy, the study provides a conceptual framework for analyzing an anthropogenic phosphorus cycle that includes four stages: extraction, fabrication and manufacturing, use, and waste management. Estimates of phosphorus flow were based on existing data as well as field research, expert advice, local accounting systems, and literature. The total phosphorus input into Hefei in 2008 reached 7810 tons, mainly as phosphate ore, chemical fertilizer, pesticides, crops and animal products. Approximately 33% of the total phosphorus input left the area, and nearly 20% of that amount was discharged as waste to surface water. Effluent containing excessive fertilizer from farming operations plays an important role in phosphorus overloads onto surface water; the other major emission source is sewage discharge. We also provide suggestions for reducing phosphorus emissions, for example reducing fertilizer use, recycling farming residues, and changing human consumption patterns.

  4. Global Climate Responses to Anthropogenic Groundwater Exploitation

    NASA Astrophysics Data System (ADS)

    Zeng, Y.; Xie, Z.

    2015-12-01

    In this study, a groundwater exploitation scheme is incorporated into the earth system model, Community Earth System Model 1.2.0 (CESM1.2.0), which is called CESM1.2_GW, and the climatic responses to anthropogenic groundwater withdrawal are then investigated on global scale. The scheme models anthropogenic groundwater exploitation and consumption, which are then divided into agricultural irrigation, industrial use and domestic use. A group of 41-year ensemble groundwater exploitation simulations with six different initial conditions, and a group of ensemble control simulations without exploitation are conducted using the developed model CESM1.2_GW with water supplies and demands estimated. The results reveal that the groundwater exploitation and water consumption cause drying effects on soil moisture in deep layers and wetting effects in upper layers, along with a rapidly declining groundwater table in Central US, Haihe River Basin in China and Northern India and Pakistan where groundwater extraction are most severe in the world. The atmosphere also responds to anthropogenic groundwater exploitation. Cooling effects on lower troposphere appear in large areas of North China Plain and of Northern India and Pakistan. Increased precipitation occurs in Haihe River Basin due to increased evapotranspiration from irrigation. Decreased precipitation occurs in Northern India because water vapor here is taken away by monsoon anomalies induced by anthropogenic alteration of groundwater. The local reducing effects of anthropogenic groundwater exploitation on total terrestrial water storage evinces that water resource is unsustainable with the current high exploitation rate. Therefore, a balance between slow groundwater withdrawal and rapid human economic development must be achieved to maintain a sustainable water resource, especially in over-exploitation regions such as Central US, Northern China, India and Pakistan.

  5. The Kepler Input Catalog

    NASA Astrophysics Data System (ADS)

    Latham, D. W.; Brown, T. M.; Monet, D. G.; Everett, M.; Esquerdo, G. A.; Hergenrother, C. W.

    2005-12-01

    The Kepler mission will monitor 170,000 planet-search targets during the first year, and 100,000 after that. The Kepler Input Catalog (KIC) will be used to select optimum targets for the search for habitable earth-like transiting planets. The KIC will include all known catalogued stars in an area of about 177 square degrees centered at RA 19:22:40 and Dec +44:30 (l=76.3 and b=+13.5). 2MASS photometry will be supplemented with new ground-based photometry obtained in the SDSS g, r, i, and z bands plus a custom filter centered on the Mg b lines, using KeplerCam on the 48-inch telescope at the Whipple Observatory on Mount Hopkins, Arizona. The photometry will be used to estimate stellar characteristics for all stars brighter than K 14.5 mag. The KIC will include effective temperature, surface gravity, metallicity, reddening, distance, and radius estimates for these stars. The CCD images are pipeline processed to produce instrumental magnitudes at PSI. The photometry is then archived and transformed to the SDSS system at HAO, where the astrophysical analysis of the stellar characteristics is carried out. The results are then merged with catalogued data at the USNOFS to produce the KIC. High dispersion spectroscopy with Hectochelle on the MMT will be used to supplement the information for many of the most interesting targets. The KIC will be released before launch for use by the astronomical community and will be available for queries over the internet. Support from the Kepler mission is gratefully acknowledged.

  6. Reactive nitrogen inputs to US lands and waterways: how certain are we about sources and fluxes?

    EPA Science Inventory

    An overabundance of reactive nitrogen (N) as a result of anthropogenic activities has led to multiple human health and environmental concerns. Efforts to address these concerns require an accurate accounting of N inputs. Here, we present a novel synthesis of data describing N inp...

  7. Reactive nitrogen inputs to US lands and waterways: how certain are we about sources and fluxes?

    EPA Science Inventory

    An overabundance of reactive nitrogen (N) as a result of anthropogenic activities has led to multiple human health and environmental concerns. Efforts to address these concerns require an accurate accounting of N inputs. Here, we present a novel synthesis of data describing N inp...

  8. Climate Response of Direct Radiative Forcing of Anthropogenic Black Carbon

    NASA Technical Reports Server (NTRS)

    Chung, Serena H.; Seinfeld,John H.

    2008-01-01

    The equilibrium climate effect of direct radiative forcing of anthropogenic black carbon (BC) is examined by 100-year simulations in the Goddard Institute for Space Studies General Circulation Model II-prime coupled to a mixed-layer ocean model. Anthropogenic BC is predicted to raise globally and annually averaged equilibrium surface air temperature by 0.20 K if BC is assumed to be externally mixed. The predicted increase is significantly greater in the Northern Hemisphere (0.29 K) than in the Southern Hemisphere (0.11 K). If BC is assumed to be internally mixed with the present day level of sulfate aerosol, the predicted annual mean surface temperature increase rises to 0.37 K globally, 0.54 K for the Northern Hemisphere, and 0.20 K for the Southern Hemisphere. The climate sensitivity of BC direct radiative forcing is calculated to be 0.6 K W (sup -1) square meters, which is about 70% of that of CO2, independent of the assumption of BC mixing state. The largest surface temperature response occurs over the northern high latitudes during winter and early spring. In the tropics and midlatitudes, the largest temperature increase is predicted to occur in the upper troposphere. Direct radiative forcing of anthropogenic BC is also predicted to lead to a change of precipitation patterns in the tropics; precipitation is predicted to increase between 0 and 20 N and decrease between 0 and 20 S, shifting the intertropical convergence zone northward. If BC is assumed to be internally mixed with sulfate instead of externally mixed, the change in precipitation pattern is enhanced. The change in precipitation pattern is not predicted to alter the global burden of BC significantly because the change occurs predominantly in regions removed from BC sources.

  9. Anthropogenic disturbances jeopardize biodiversity conservation within tropical rainforest reserves

    PubMed Central

    Martínez-Ramos, Miguel; Ortiz-Rodríguez, Iván A.; Piñero, Daniel; Dirzo, Rodolfo; Sarukhán, José

    2016-01-01

    Anthropogenic disturbances affecting tropical forest reserves have been documented, but their ecological long-term cumulative effects are poorly understood. Habitat fragmentation and defaunation are two major anthropogenic threats to the integrity of tropical reserves. Based on a long-term (four decades) study, we document how these disturbances synergistically disrupt ecological processes and imperil biodiversity conservation and ecosystem functioning at Los Tuxtlas, the northernmost tropical rainforest reserve in the Americas. Deforestation around this reserve has reduced the reserve to a medium-sized fragment (640 ha), leading to an increased frequency of canopy-gap formation. In addition, hunting and habitat loss have caused the decline or local extinction of medium and large herbivores. Combining empirical, experimental, and modeling approaches, we support the hypothesis that such disturbances produced a demographic explosion of the long-lived (≈120 y old, maximum height of 7 m) understory palm Astrocaryum mexicanum, whose population has increased from 1,243–4,058 adult individuals per hectare in only 39 y (annual growth rate of ca. 3%). Faster gap formation increased understory light availability, enhancing seed production and the growth of immature palms, whereas release from mammalian herbivory and trampling increased survival of seedlings and juveniles. In turn, the palm’s demographic explosion was followed by a reduction of tree species diversity, changing forest composition, altering the relative contribution of trees to forest biomass, and disrupting litterfall dynamics. We highlight how indirect anthropogenic disturbances (e.g., palm proliferation) on otherwise protected areas threaten tropical conservation, a phenomenon that is currently eroding the planet’s richest repositories of biodiversity. PMID:27071122

  10. Anthropogenic disturbances jeopardize biodiversity conservation within tropical rainforest reserves.

    PubMed

    Martínez-Ramos, Miguel; Ortiz-Rodríguez, Iván A; Piñero, Daniel; Dirzo, Rodolfo; Sarukhán, José

    2016-05-10

    Anthropogenic disturbances affecting tropical forest reserves have been documented, but their ecological long-term cumulative effects are poorly understood. Habitat fragmentation and defaunation are two major anthropogenic threats to the integrity of tropical reserves. Based on a long-term (four decades) study, we document how these disturbances synergistically disrupt ecological processes and imperil biodiversity conservation and ecosystem functioning at Los Tuxtlas, the northernmost tropical rainforest reserve in the Americas. Deforestation around this reserve has reduced the reserve to a medium-sized fragment (640 ha), leading to an increased frequency of canopy-gap formation. In addition, hunting and habitat loss have caused the decline or local extinction of medium and large herbivores. Combining empirical, experimental, and modeling approaches, we support the hypothesis that such disturbances produced a demographic explosion of the long-lived (≈120 y old, maximum height of 7 m) understory palm Astrocaryum mexicanum, whose population has increased from 1,243-4,058 adult individuals per hectare in only 39 y (annual growth rate of ca 3%). Faster gap formation increased understory light availability, enhancing seed production and the growth of immature palms, whereas release from mammalian herbivory and trampling increased survival of seedlings and juveniles. In turn, the palm's demographic explosion was followed by a reduction of tree species diversity, changing forest composition, altering the relative contribution of trees to forest biomass, and disrupting litterfall dynamics. We highlight how indirect anthropogenic disturbances (e.g., palm proliferation) on otherwise protected areas threaten tropical conservation, a phenomenon that is currently eroding the planet's richest repositories of biodiversity.

  11. Climate Response of Direct Radiative Forcing of Anthropogenic Black Carbon

    NASA Technical Reports Server (NTRS)

    Chung, Serena H.; Seinfeld,John H.

    2008-01-01

    The equilibrium climate effect of direct radiative forcing of anthropogenic black carbon (BC) is examined by 100-year simulations in the Goddard Institute for Space Studies General Circulation Model II-prime coupled to a mixed-layer ocean model. Anthropogenic BC is predicted to raise globally and annually averaged equilibrium surface air temperature by 0.20 K if BC is assumed to be externally mixed. The predicted increase is significantly greater in the Northern Hemisphere (0.29 K) than in the Southern Hemisphere (0.11 K). If BC is assumed to be internally mixed with the present day level of sulfate aerosol, the predicted annual mean surface temperature increase rises to 0.37 K globally, 0.54 K for the Northern Hemisphere, and 0.20 K for the Southern Hemisphere. The climate sensitivity of BC direct radiative forcing is calculated to be 0.6 K W (sup -1) square meters, which is about 70% of that of CO2, independent of the assumption of BC mixing state. The largest surface temperature response occurs over the northern high latitudes during winter and early spring. In the tropics and midlatitudes, the largest temperature increase is predicted to occur in the upper troposphere. Direct radiative forcing of anthropogenic BC is also predicted to lead to a change of precipitation patterns in the tropics; precipitation is predicted to increase between 0 and 20 N and decrease between 0 and 20 S, shifting the intertropical convergence zone northward. If BC is assumed to be internally mixed with sulfate instead of externally mixed, the change in precipitation pattern is enhanced. The change in precipitation pattern is not predicted to alter the global burden of BC significantly because the change occurs predominantly in regions removed from BC sources.

  12. Anthropogenic influences on the physical state of submicron particulate matter over a tropical forest

    NASA Astrophysics Data System (ADS)

    Bateman, Adam P.; Gong, Zhaoheng; Harder, Tristan H.; de Sá, Suzane S.; Wang, Bingbing; Castillo, Paulo; China, Swarup; Liu, Yingjun; O'Brien, Rachel E.; Palm, Brett B.; Shiu, Hung-Wei; Cirino, Glauber G.; Thalman, Ryan; Adachi, Kouji; Lizabeth Alexander, M.; Artaxo, Paulo; Bertram, Allan K.; Buseck, Peter R.; Gilles, Mary K.; Jimenez, Jose L.; Laskin, Alexander; Manzi, Antonio O.; Sedlacek, Arthur; Souza, Rodrigo A. F.; Wang, Jian; Zaveri, Rahul; Martin, Scot T.

    2017-02-01

    The occurrence of nonliquid and liquid physical states of submicron atmospheric particulate matter (PM) downwind of an urban region in central Amazonia was investigated. Measurements were conducted during two intensive operating periods (IOP1 and IOP2) that took place during the wet and dry seasons of the GoAmazon2014/5 campaign. Air masses representing variable influences of background conditions, urban pollution, and regional- and continental-scale biomass burning passed over the research site. As the air masses varied, particle rebound fraction, an indicator of physical state, was measured in real time at ground level using an impactor apparatus. Micrographs collected by transmission electron microscopy confirmed that liquid particles adhered, while nonliquid particles rebounded. Relative humidity (RH) was scanned to collect rebound curves. When the apparatus RH matched ambient RH, 95 % of the particles adhered as a campaign average. Secondary organic material, produced for the most part by the oxidation of volatile organic compounds emitted from the forest, produces liquid PM over this tropical forest. During periods of anthropogenic influence, by comparison, the rebound fraction dropped to as low as 60 % at 95 % RH. Analyses of the mass spectra of the atmospheric PM by positive-matrix factorization (PMF) and of concentrations of carbon monoxide, total particle number, and oxides of nitrogen were used to identify time periods affected by anthropogenic influences, including both urban pollution and biomass burning. The occurrence of nonliquid PM at high RH correlated with these indicators of anthropogenic influence. A linear model having as output the rebound fraction and as input the PMF factor loadings explained up to 70 % of the variance in the observed rebound fractions. Anthropogenic influences can contribute to the presence of nonliquid PM in the atmospheric particle population through the combined effects of molecular species that increase viscosity when

  13. Anthropogenic influences on the physical state of submicron particulate matter over a tropical forest

    DOE PAGES

    Bateman, Adam P.; Gong, Zhaoheng; Harder, Tristan H.; ...

    2017-02-06

    The occurrence of nonliquid and liquid physical states of submicron atmospheric particulate matter (PM) downwind of an urban region in central Amazonia was investigated. Measurements were conducted during two intensive operating periods (IOP1 and IOP2) that took place during the wet and dry seasons of the GoAmazon2014/5 campaign. Air masses representing variable influences of background conditions, urban pollution, and regional- and continental-scale biomass burning passed over the research site. As the air masses varied, particle rebound fraction, an indicator of physical state, was measured in real time at ground level using an impactor apparatus. Micrographs collected by transmission electron microscopymore » confirmed that liquid particles adhered, while nonliquid particles rebounded. Relative humidity (RH) was scanned to collect rebound curves. When the apparatus RH matched ambient RH, 95 % of the particles adhered as a campaign average. Secondary organic material, produced for the most part by the oxidation of volatile organic compounds emitted from the forest, produces liquid PM over this tropical forest. During periods of anthropogenic influence, by comparison, the rebound fraction dropped to as low as 60 % at 95 % RH. Analyses of the mass spectra of the atmospheric PM by positive-matrix factorization (PMF) and of concentrations of carbon monoxide, total particle number, and oxides of nitrogen were used to identify time periods affected by anthropogenic influences, including both urban pollution and biomass burning. The occurrence of nonliquid PM at high RH correlated with these indicators of anthropogenic influence. A linear model having as output the rebound fraction and as input the PMF factor loadings explained up to 70 % of the variance in the observed rebound fractions. Anthropogenic influences can contribute to the presence of nonliquid PM in the atmospheric particle population through the combined effects of molecular species that increase

  14. Challenges for present and future estimates of anthropogenic carbon in the Indian Ocean

    NASA Astrophysics Data System (ADS)

    Goyet, C.; Touratier, F.

    One of the main challenges we face today is to determine the evolution of the penetration of anthropogenic CO2 into the Indian Ocean and its impacts on marine and human life. Anthropogenic CO2 reaches the ocean via air-sea interactions as well as riverine inputs. It is then stored in the ocean and follows the oceanic circulation. As the carbon dioxide from the atmosphere penetrates into the sea, it reacts with water and acidifies the ocean. Consequently, the whole marine ecosystem is perturbed, thus potentially affecting the food web, which has, in turn, a direct impact on seafood supply for humans. Naturally, this will mainly affect the growing number of people living in coastal areas. Although anthropogenic CO2 in the ocean is identical with natural CO2 and therefore cannot be detected alone, many approaches are available today to estimate it. Since most of the results of these methods are globally in agreement, here we chose one of these methods, the tracer using oxygen, total inorganic carbon, and total alkalinity (TrOCA) approach, to compute the 3-D distribution of the anthropogenic CO2 concentrations throughout the Indian Ocean. The results of this distribution clearly illustrate the contrast between the Arabian Sea and the Bay of Bengal. They further show the importance of the southern part of this ocean that carries some anthropogenic CO2 at great depths. In order to determine the future anthropogenic impacts on the Indian Ocean, it is urgent and necessary to understand the present state. As the seawater temperature increases, how and how fast will the ocean circulation change? What will the impacts on seawater properties be? Many people are living on the bordering coasts, how will they be affected?

  15. Anthropogenic influences on the physical state of submicron particulate matter over a tropical forest

    SciTech Connect

    Bateman, Adam P.; Gong, Zhaoheng; Harder, Tristan H.; de Sá, Suzane S.; Wang, Bingbing; Castillo, Paulo; China, Swarup; Liu, Yingjun; O'Brien, Rachel E.; Palm, Brett B.; Shiu, Hung-Wei; Cirino, Glauber G.; Thalman, Ryan; Adachi, Kouji; Alexander, M. Lizabeth; Artaxo, Paulo; Bertram, Allan K.; Buseck, Peter R.; Gilles, Mary K.; Jimenez, Jose L.; Laskin, Alexander; Manzi, Antonio O.; Sedlacek, Arthur; Souza, Rodrigo A. F.; Wang, Jian; Zaveri, Rahul; Martin, Scot T.

    2017-01-01

    The occurrence of nonliquid and liquid physical states of submicron atmospheric particulate matter (PM) downwind of an urban region in central Amazonia was investigated. Measurements were conducted during two intensive operating periods (IOP1 and IOP2) that took place during the wet and dry seasons of the GoAmazon2014/5 campaign. Air masses representing variable influences of background conditions, urban pollution, and regional- and continental-scale biomass burning passed over the research site. As the air masses varied, particle rebound fraction, an indicator of physical state, was measured in real time at ground level using an impactor apparatus. Micrographs collected by transmission electron microscopy confirmed that liquid particles adhered, while nonliquid particles rebounded. Relative humidity (RH) was scanned to collect rebound curves. When the apparatus RH matched ambient RH, 95 % of the particles adhered as a campaign average. Secondary organic material, produced for the most part by the oxidation of volatile organic compounds emitted from the forest, produces liquid PM over this tropical forest. During periods of anthropogenic influence, by comparison, the rebound fraction dropped to as low as 60 % at 95 % RH. Analyses of the mass spectra of the atmospheric PM by positive-matrix factorization (PMF) and of concentrations of carbon monoxide, total particle number, and oxides of nitrogen were used to identify time periods affected by anthropogenic influences, including both urban pollution and biomass burning. The occurrence of nonliquid PM at high RH correlated with these indicators of anthropogenic influence. A linear model having as output the rebound fraction and as input the PMF factor loadings explained up to 70 % of the variance in the observed rebound fractions. Anthropogenic influences can contribute to the presence of nonliquid PM in the atmospheric particle population through the combined effects of molecular species that increase

  16. Lead Toxicity

    MedlinePlus

    Agency for Toxic Substances and Disease Registry Case Studies in Environmental Medicine (CSEM) Patient Information Sheet Lead Toxicity What is lead? How are people exposed to lead? • Lead is a soft, blue- ...

  17. Lead Poisoning

    MedlinePlus

    ... high levels of lead in household dust. DRINKING WATER: Lead may get into drinking water when materials used in plumbing materials, such as ... and dishware. Lead may also be in contaminated water. Lead poisoning is harmful to human health and ...

  18. Serial Input Output

    SciTech Connect

    Waite, Anthony; /SLAC

    2011-09-07

    Serial Input/Output (SIO) is designed to be a long term storage format of a sophistication somewhere between simple ASCII files and the techniques provided by inter alia Objectivity and Root. The former tend to be low density, information lossy (floating point numbers lose precision) and inflexible. The latter require abstract descriptions of the data with all that that implies in terms of extra complexity. The basic building blocks of SIO are streams, records and blocks. Streams provide the connections between the program and files. The user can define an arbitrary list of streams as required. A given stream must be opened for either reading or writing. SIO does not support read/write streams. If a stream is closed during the execution of a program, it can be reopened in either read or write mode to the same or a different file. Records represent a coherent grouping of data. Records consist of a collection of blocks (see next paragraph). The user can define a variety of records (headers, events, error logs, etc.) and request that any of them be written to any stream. When SIO reads a file, it first decodes the record name and if that record has been defined and unpacking has been requested for it, SIO proceeds to unpack the blocks. Blocks are user provided objects which do the real work of reading/writing the data. The user is responsible for writing the code for these blocks and for identifying these blocks to SIO at run time. To write a collection of blocks, the user must first connect them to a record. The record can then be written to a stream as described above. Note that the same block can be connected to many different records. When SIO reads a record, it scans through the blocks written and calls the corresponding block object (if it has been defined) to decode it. Undefined blocks are skipped. Each of these categories (streams, records and blocks) have some characteristics in common. Every stream, record and block has a name with the condition that each

  19. SDR Input Power Estimation Algorithms

    NASA Technical Reports Server (NTRS)

    Nappier, Jennifer M.; Briones, Janette C.

    2013-01-01

    The General Dynamics (GD) S-Band software defined radio (SDR) in the Space Communications and Navigation (SCAN) Testbed on the International Space Station (ISS) provides experimenters an opportunity to develop and demonstrate experimental waveforms in space. The SDR has an analog and a digital automatic gain control (AGC) and the response of the AGCs to changes in SDR input power and temperature was characterized prior to the launch and installation of the SCAN Testbed on the ISS. The AGCs were used to estimate the SDR input power and SNR of the received signal and the characterization results showed a nonlinear response to SDR input power and temperature. In order to estimate the SDR input from the AGCs, three algorithms were developed and implemented on the ground software of the SCAN Testbed. The algorithms include a linear straight line estimator, which used the digital AGC and the temperature to estimate the SDR input power over a narrower section of the SDR input power range. There is a linear adaptive filter algorithm that uses both AGCs and the temperature to estimate the SDR input power over a wide input power range. Finally, an algorithm that uses neural networks was designed to estimate the input power over a wide range. This paper describes the algorithms in detail and their associated performance in estimating the SDR input power.

  20. Intermediate inputs and economic productivity.

    PubMed

    Baptist, Simon; Hepburn, Cameron

    2013-03-13

    Many models of economic growth exclude materials, energy and other intermediate inputs from the production function. Growing environmental pressures and resource prices suggest that this may be increasingly inappropriate. This paper explores the relationship between intermediate input intensity, productivity and national accounts using a panel dataset of manufacturing subsectors in the USA over 47 years. The first contribution is to identify sectoral production functions that incorporate intermediate inputs, while allowing for heterogeneity in both technology and productivity. The second contribution is that the paper finds a negative correlation between intermediate input intensity and total factor productivity (TFP)--sectors that are less intensive in their use of intermediate inputs have higher productivity. This finding is replicated at the firm level. We propose tentative hypotheses to explain this association, but testing and further disaggregation of intermediate inputs is left for further work. Further work could also explore more directly the relationship between material inputs and economic growth--given the high proportion of materials in intermediate inputs, the results in this paper are suggestive of further work on material efficiency. Depending upon the nature of the mechanism linking a reduction in intermediate input intensity to an increase in TFP, the implications could be significant. A third contribution is to suggest that an empirical bias in productivity, as measured in national accounts, may arise due to the exclusion of intermediate inputs. Current conventions of measuring productivity in national accounts may overstate the productivity of resource-intensive sectors relative to other sectors.

  1. Thallium isotope variations in anthropogenically-affected soils

    NASA Astrophysics Data System (ADS)

    Vanek, Ales; Chrastny, Vladislav; Penizek, Vit; Mihaljevic, Martin; Komarek, Michael; Cabala, Jerzy

    2014-05-01

    Our preliminary data from soils impacted by long-term Tl deposition in the vicinity of a primary/secondary Zn smelter at Olkusz (Poland) indicate apparent variability of ɛ205Tl within soil profiles. The identified ɛ205Tl values presented for the forest soil profile reached -1.7 in the surface/organic horizon, +1.9 in the organo-mineral horizon (Ap), and +1.0 in the mineral horizon (C). This finding suggests both the enrichment of 203Tl isotope in the topsoil, as well as its preferential release during smelting operations, as "lighter" Tl tends to enter the emissions during a high-temperature process. The maximum ɛ205Tl value in the subsurface horizon Ap is in accordance with the concentration peak of oxalate-extractable Mn, indicating the presence of amorphous/poorly-crystalline Mn oxides with a potential to isotopically fractionate Tl toward the "heavier" fraction. The Tl isotope signature in the bottom horizon probably reflects the composition of a local geochemical anomaly of Tl. However, a portion of mobile (anthropogenic) Tl with negative ɛ205Tl moving downwards in the soil profile cannot be neglected. In general, there is no detailed information about the biogeochemical cycling and variations of Tl isotopes in areas affected by significant anthropogenic inputs of the metal (e.g., coal burning and primary metallurgy); the questions of the degree to which the factors such as soil (and sediment) chemistry, mineralogy, local biota, and pollution source control Tl isotope fractionation remain unresolved. Therefore, further research on the topic is needed before any principal conclusions will be made.

  2. Bayesian calibration of groundwater models with input data uncertainty

    NASA Astrophysics Data System (ADS)

    Xu, Tianfang; Valocchi, Albert J.; Ye, Ming; Liang, Feng; Lin, Yu-Feng

    2017-04-01

    Effective water resources management typically relies on numerical models to analyze groundwater flow and solute transport processes. Groundwater models are often subject to input data uncertainty, as some inputs (such as recharge and well pumping rates) are estimated and subject to uncertainty. Current practices of groundwater model calibration often overlook uncertainties in input data; this can lead to biased parameter estimates and compromised predictions. Through a synthetic case study of surface-ground water interaction under changing pumping conditions and land use, we investigate the impacts of uncertain pumping and recharge rates on model calibration and uncertainty analysis. We then present a Bayesian framework of model calibration to handle uncertain input of groundwater models. The framework implements a marginalizing step to account for input data uncertainty when evaluating likelihood. It was found that not accounting for input uncertainty may lead to biased, overconfident parameter estimates because parameters could be over-adjusted to compensate for possible input data errors. Parameter compensation can have deleterious impacts when the calibrated model is used to make forecast under a scenario that is different from calibration conditions. By marginalizing input data uncertainty, the Bayesian calibration approach effectively alleviates parameter compensation and gives more accurate predictions in the synthetic case study. The marginalizing Bayesian method also decomposes prediction uncertainty into uncertainties contributed by parameters, input data, and measurements. The results underscore the need to account for input uncertainty to better inform postmodeling decision making.

  3. Isotopic evidence of contaminant lead in the South Atlantic troposphere and surface waters

    NASA Astrophysics Data System (ADS)

    Alleman, L. Y.; Church, T. M.; Véron, A. J.; Kim, G.; Hamelin, B.; Flegal, A. R.

    The third Intergovernmental Oceanographic Commission (IOC) Baseline Contaminant cruise (May-June 1996) has established the first lead isotopic compositions in the surface water and the atmosphere of the Equatorial and South Atlantic Ocean. These ratios have evidenced both anthropogenic and natural origins of lead along the cruise transect (from 33°S to 10°N). The isotopic gradients tentatively have been, attributed to aeolian as well as surface-water advective inputs from a suite of rather local and remote sources to the Southern Hemisphere. Relatively low 206Pb/ 207Pb ratios (x±sd) were encountered within the South Equatorial Current between 17°S and 5°S (1.156±0.003). Those were bracketed by more radiogenic ratios at higher latitudes in the Southern Hemisphere (33°S to 23°S), within the Brazil Current and the Subtropical Gyre (1.163±0.003), and in the Northern Hemisphere (0° to 10°N) (1.165±0.005). The latter were comparable to ratios of surface water in the North Atlantic Equatorial Ocean (1.169±0.006), under a combined contaminant influence of both North American westerlies (1.19-1.20) and European easterlies (1.155-1.165). That predominance of contaminant lead contrasts with the measurable presence of natural lead in surface waters of the Equatorial Ocean, which are attributed to aeolian inputs of Saharan dust. The ratios of lead in surface waters at higher latitudes in the South Atlantic are characteristic of anthropogenic lead aerosols also detected in Antarctic ice, and could substantiate as well the hypothesized aerosol recycling of lead by sea-spray emission in the far Southern Hemisphere. The atmospheric lead isotopic compositions ( 206Pb/ 207Pb) in bulk depositions (1.171±0.006), precipitation (1.171±0.006) and aerosols (1.168±0.011) were, generally, more radiogenic than the surface waters (1.162±0.005). Beside a poor representation of a short term atmospheric sampling, this difference could reflect a recent evolution in atmospheric

  4. Hidden Markov models for estimating animal mortality from anthropogenic hazards

    EPA Science Inventory

    Carcasses searches are a common method for studying the risk of anthropogenic hazards to wildlife, including non-target poisoning and collisions with anthropogenic structures. Typically, numbers of carcasses found must be corrected for scavenging rates and imperfect detection. ...

  5. Hidden Markov models for estimating animal mortality from anthropogenic hazards

    EPA Science Inventory

    Carcasses searches are a common method for studying the risk of anthropogenic hazards to wildlife, including non-target poisoning and collisions with anthropogenic structures. Typically, numbers of carcasses found must be corrected for scavenging rates and imperfect detection. ...

  6. New insights into impacts of anthropogenic nutrients on urban ecosystem processes on the Southern California coastal shelf: Introduction and synthesis

    NASA Astrophysics Data System (ADS)

    Howard, Meredith D. A.; Kudela, Raphael M.; McLaughlin, Karen

    2017-02-01

    Anthropogenic nutrient inputs are one of the most important factors contributing to eutrophication of coastal waters. Coastal upwelling regions are naturally highly variable, exhibiting faster flushing and lower retention times than estuarine systems. As such, these regions are considered more resilient to anthropogenic influences than other coastal waters. Recent studies have shown our perception of the sustainability of these systems may be flawed and that anthropogenic nutrients can have an impact at local and regional spatial scales within these larger upwelling ecosystems. Maintenance of an outfall pipe discharging wastewater effluent to the Southern California Bight (SCB) provided an opportunity to study effects of anthropogenic nutrient inputs on a near-shore coastal ecosystem. The diversion of wastewater effluent from a primary, offshore outfall to a secondary, near-shore outfall set up a large-scale, in situ experiment allowing researchers to track the fate of wastewater plumes as they were ;turned off; in one area and ;turned on; in another. In this introduction to a special issue, we synthesize results of one such wastewater diversion conducted by the Orange County Sanitation District (OCSD) during fall 2012. Anthropogenic nitrogen (N) from point-source discharges altered biogeochemical cycling and the community composition of bacteria and phytoplankton. Nitrification of ammonium to nitrate in wastewater effluent close to outfalls constituted a significant source of N utilized by the biological community that should be considered in quantifying ;new; production. The microbial-loop component of the plankton community played a significant role, exemplified by a large response of heterotrophic bacteria to wastewater effluent that resulted in nutrient immobilization within the bacterial food web. This response, combined with the photosynthetic inhibition of phytoplankton due to disinfection byproducts, suppressed phytoplankton responses. Our findings have

  7. Anthropogenic Osmium in Airborne Particles from Woods Hole, Massachusetts, USA

    NASA Astrophysics Data System (ADS)

    Peucker-Ehrenbrink, B.; Sen, I. S.; Geboy, N.

    2012-12-01

    The global geochemical cycle of osmium has been significantly disturbed by the introduction of automobile exhaust catalysts to convert noxious gas emissions into more benign forms. Anthropogenic osmium has been reported in rainwater, snow, and in the urban airborne particles from around the world to reveal global-scale osmium pollution [1, 2]. In this study, we report on the platinum group element (PGE) concentrations and osmium isotope ratios of airborne particles (PM10) collected in Woods Hole, a small coastal town in Massachusetts to better understand inputs of anthropogenic osmium to rural environments. We further investigate the use of osmium isotopes to track sources of airborne particles and support source apportionment studies on a continental scale. The samples used in this study were collected at Woods Hole Oceanographic Institution over one year (2008-2009). From this collection twelve samples for which the backward air mass trajectories have been determined were selected for osmium isotope analyses. Our results show that the osmium and platinum concentrations are an order of magnitude lower when compared to downtown Boston [2]. The average Os, Pt and Ir concentrations are 0.006±0.012, 0.019±0.023, and 0.685±0.634 pg m-3, respectively. The 187Os/188Os of the aerosols range from 0.275 to 0.788. As continental crust is radiogenic (187Os/188Os >1) and PGE ore bodies generally have unradiogenic 187Os/188Os (~0.2), the unradiogenic 187Os/188Os signature of the aerosols indicates anthropogenic contributions. With 95% of the total osmium mobilization on land being attributed to human activities [3], it is clear that human imprint on airborne particles is not restricted to urban centers with high traffic flows, but also affects rural environments. Aerosol particles that have backward air mass trajectories from the Southwest, the densely populated and industrialized Eastern seaboard, are characterized by unradiogenic osmium, while air masses from the North

  8. Anthropogenic Aerosols and the Dust Bowl

    NASA Astrophysics Data System (ADS)

    Cazavilan, E. J.; Leibensperger, E. M.

    2014-12-01

    We use a general circulation model (GISS GCM ModelE) to study the impact of anthropogenic aerosols on the 1930s Dust Bowl. The Dust Bowl was primarily forced by anomalous sea surface temperatures, but may have been partially shaped by the large amounts of black carbon emitted at that time. A simulation using observed 1932-1938 sea surface temperature and sea ice distributions reveal drier and warmer conditions in the central U.S. Adding the influence of 1930s anthropogenic aerosols exacerbates the drying and warm conditions (0.2 °C increase over mid-west continental US, and a decrease of -0.1 mm/day of precipitation). We find that these changes are concurrent with a weakening and shift of the Bermuda High.

  9. Quantifying the Anthropogenic Footprint in Eastern China

    PubMed Central

    Meng, Chunlei; Dou, Youjun

    2016-01-01

    Urban heat island (UHI) is one of the most focuses in urban climate study. The parameterization of the anthropogenic heat (AH) is crucial important in UHI study, but universal method to parameterize the spatial pattern of the AH is lacking now. This paper uses the NOAA DMSP/OLS nighttime light data to parameterize the spatial pattern of the AH. Two experiments were designed and performed to quantify the influences of the AH to land surface temperature (LST) in eastern China and 24 big cities. The annual mean heating caused by AH is up to 1 K in eastern China. This paper uses the relative LST differences rather than the absolute LST differences between the control run and contrast run of common land model (CoLM) to find the drivers. The heating effect of the anthropogenic footprint has less influence on relatively warm and wet cities. PMID:27067132

  10. Quantifying the Anthropogenic Footprint in Eastern China.

    PubMed

    Meng, Chunlei; Dou, Youjun

    2016-04-12

    Urban heat island (UHI) is one of the most focuses in urban climate study. The parameterization of the anthropogenic heat (AH) is crucial important in UHI study, but universal method to parameterize the spatial pattern of the AH is lacking now. This paper uses the NOAA DMSP/OLS nighttime light data to parameterize the spatial pattern of the AH. Two experiments were designed and performed to quantify the influences of the AH to land surface temperature (LST) in eastern China and 24 big cities. The annual mean heating caused by AH is up to 1 K in eastern China. This paper uses the relative LST differences rather than the absolute LST differences between the control run and contrast run of common land model (CoLM) to find the drivers. The heating effect of the anthropogenic footprint has less influence on relatively warm and wet cities.

  11. Quantifying the Anthropogenic Footprint in Eastern China

    NASA Astrophysics Data System (ADS)

    Meng, Chunlei; Dou, Youjun

    2016-04-01

    Urban heat island (UHI) is one of the most focuses in urban climate study. The parameterization of the anthropogenic heat (AH) is crucial important in UHI study, but universal method to parameterize the spatial pattern of the AH is lacking now. This paper uses the NOAA DMSP/OLS nighttime light data to parameterize the spatial pattern of the AH. Two experiments were designed and performed to quantify the influences of the AH to land surface temperature (LST) in eastern China and 24 big cities. The annual mean heating caused by AH is up to 1 K in eastern China. This paper uses the relative LST differences rather than the absolute LST differences between the control run and contrast run of common land model (CoLM) to find the drivers. The heating effect of the anthropogenic footprint has less influence on relatively warm and wet cities.

  12. Sources of anthropogenic radionuclides in the environment: a review.

    PubMed

    Hu, Qin-Hong; Weng, Jian-Qing; Wang, Jin-Sheng

    2010-06-01

    Studies of radionuclides in the environment have entered a new era with the renaissance of nuclear energy and associated fuel reprocessing, geological disposal of high-level nuclear wastes, and concerns about national security with respect to nuclear non-proliferation. This work presents an overview on sources of anthropogenic radionuclides in the environment, as well as a brief discussion of salient geochemical behavior of important radionuclides. We first discuss the following major anthropogenic sources and current developments that have lead, or could potentially contribute, to the radionuclide contamination of the environment: (1) nuclear weapons program; (2) nuclear weapons testing; (3) nuclear power plants; (4) uranium mining and milling; (5) commercial fuel reprocessing; (6) geological repository of high-level nuclear wastes that include radionuclides might be released in the future, and (7) nuclear accidents. Then, we briefly summarize the inventory of radionuclides (99)Tc and (129)I, as well as geochemical behavior for radionuclides (99)Tc, (129)I, and (237)Np, because of their complex geochemical behavior, long half-lives, and presumably high mobility in the environment; biogeochemical cycling and environment risk assessment must take into account speciation of these redox-sensitive radionuclides.

  13. Anthropogenic versus mineral aerosols in the stimulation of microbial planktonic communities in coastal waters of the northwestern Mediterranean Sea.

    PubMed

    Marín, I; Nunes, S; Sánchez-Pérez, E D; Aparicio, F L; Estrada, M; Marrasé, C; Moreno, T; Wagener, T; Querol, X; Peters, F

    2017-01-01

    The atmosphere of the northwestern (NW) Mediterranean Sea is affected by continuous inputs of anthropogenic aerosols and episodic Saharan dust events. These atmospheric inputs deliver to the surface waters high amounts of macronutrients and trace metals that can constitute their main source at certain times of the year. The effect of both anthropogenic and crustal particles over the autotrophic and heterotrophic planktonic community assembles was evaluated through three microcosm experiments carried out in the summer of 2013 and in the winter and spring of 2014 at an urban coastal location of the NW Mediterranean (Barcelona, Spain). Particles were added to seawater at a concentration of 0.8mgl(-1). The results showed that (i) a greater stimulation of the whole community was observed in summer and spring than in winter; (ii) both kinds of aerosols produced an increase in the growth of phytoplankton, although the stimulation of nanoeukaryotes was significantly larger with anthropogenic aerosols; and (iii) bacterial abundance increased more with mineral dust, whereas bacterial production was more stimulated with anthropogenic inputs. Overall, the effect of atmospheric particles was dependent on their composition and solubility in seawater, as well as on the initial biogeochemical conditions present in the seawater and had the potential to change the net metabolic balance of the microbial planktonic community. Copyright © 2016 Elsevier B.V. All rights reserved.

  14. Anthropogenic Sulfate, Clouds, and Climate Forcing

    NASA Technical Reports Server (NTRS)

    Ghan, Steven J.

    1997-01-01

    This research work is a joint effort between research groups at the Battelle Pacific Northwest Laboratory, Virginia Tech University, Georgia Institute of Technology, Brookhaven National Laboratory, and Texas A&M University. It has been jointly sponsored by the National Aeronautics and Space Administration, the U.S. Department of Energy, and the U.S. Environmental Protection Agency. In this research, a detailed tropospheric aerosol-chemistry model that predicts oxidant concentrations as well as concentrations of sulfur dioxide and sulfate aerosols has been coupled to a general circulation model that distinguishes between cloud water mass and cloud droplet number. The coupled model system has been first validated and then used to estimate the radiative impact of anthropogenic sulfur emissions. Both the direct radiative impact of the aerosols and their indirect impact through their influence on cloud droplet number are represented by distinguishing between sulfuric acid vapor and fresh and aged sulfate aerosols, and by parameterizing cloud droplet nucleation in terms of vertical velocity and the number concentration of aged sulfur aerosols. Natural sulfate aerosols, dust, and carbonaceous and nitrate aerosols and their influence on the radiative impact of anthropogenic sulfate aerosols, through competition as cloud condensation nuclei, will also be simulated. Parallel simulations with and without anthropogenic sulfur emissions are performed for a global domain. The objectives of the research are: To couple a state-of-the-art tropospheric aerosol-chemistry model with a global climate model. To use field and satellite measurements to evaluate the treatment of tropospheric chemistry and aerosol physics in the coupled model. To use the coupled model to simulate the radiative (and ultimately climatic) impacts of anthropogenic sulfur emissions.

  15. The topographic signature of anthropogenic geomorphic processes

    NASA Astrophysics Data System (ADS)

    Tarolli, P.; Sofia, G.

    2014-12-01

    Within an abiotic-dominated context, geomorphologic patterns and dynamics are single expressions of trade-offs between the physical resistance forces, and the mechanical and chemical forces related to climate and erosion. Recently, however, it has become essential for the geomorphological community to take into account also biota as a fundamental geomorphologic agent acting from local to regional scales. However, while there is a recent flourishing literature about the impacts of vegetation on geomorphic processes, the study of anthropogenic pressure on geomorphology is still at its early stages. Humans are indeed among the most prominent geomorphic agents, redistributing land surface, and causing drastic changes to the geomorphic organization of the landscape (e.g. intensive agriculture, urbanization), with direct consequences on land degradation and watershed response. The reconstruction or identification of artificial or anthropogenic topographies, therefore, provides a mechanism for quantifying anthropogenic changes to the landscape systems in the context of the Anthropocene epoch. High-resolution topographic data derived from the recent remote sensing technologies (e.g. lidar, SAR, SfM), offer now new opportunities to recognize better understand geomorphic processes from topographic signatures, especially in engineered landscapes where the direct anthropic alteration of processes is significant. It is possible indeed to better recognize human-induced geomorphic and anthropogenic features (e.g. road networks, agricultural terraces), and the connected erosion. The study presented here may allow improved understanding and targeted mitigation of the processes driving geomorphic changes during urban development and help guide future research directions for development-based watershed studies. Human society is deeply affecting the environment with consequences on the landscape. It is therefore fundamental to establish greater management control over the Earth

  16. Remobilisation of industrial lead depositions in ash during Australian wildfires.

    PubMed

    Wu, Liqin; Taylor, Mark Patrick; Handley, Heather K

    2017-12-01

    This study examined the recycling of lead (Pb) in ash from wildfires, its source and potential contribution to environmental contamination. Ash from wildfires was collected from four Australian sites following uncontrolled fires during 2012 to 2013 close to major urban populations in Sydney (New South Wales), Hobart (Tasmania) and Adelaide (South Australia). The samples were analysed for their total Pb concentration and Pb isotopic composition to determine the sources of Pb and the extent, if any, of industrial contamination and its recycling into the ecosystem. Median ash concentrations (23mg/kg) released from a wildfire close to Australia's largest city, Sydney, exceeded the median ash Pb concentrations from wildfires from the less populated locations of Hobart, Adelaide and NSW Central Coast. Lead isotopic compositions of Duffys Forest wildfire ash demonstrate that anthropogenic inputs from legacy leaded petrol depositions were the predominant source of contamination. Despite the cessation of leaded petrol use in Australia in 2002, historic petrol Pb deposits continue to be a substantial source of contamination in ash: petrol Pb contributed 35% of the Pb in the Woy Woy ash, 73% in Duffys Forest ash, 39% in Forcett ash and 5% in Cherryville ash. The remobilisation of legacy industrial Pb depositions by wildfires in ash results in it being a persistent and problematic contaminant in contemporary environmental systems because of its known toxicity. Copyright © 2017 Elsevier B.V. All rights reserved.

  17. Assessing anthropogenic sources of mercury in soil in Wanshan Hg mining area, Guizhou, China.

    PubMed

    Dai, Zhihui; Feng, Xinbin; Zhang, Chao; Wang, Jingfu; Jiang, Taiming; Xiao, Houjun; Li, Yu; Wang, Xun; Qiu, Guangle

    2013-11-01

    Long-term mining and smelting activities brought a series of environmental issues into soils in Wanshan mercury (Hg) mining area (WMMA), Guizhou, China. Several studies have been published on the concentrations of Hg in local soils, but a comprehensive assessment of the mass of Hg in soil induced by anthropogenic activities, as presented in this paper, has not been previously conducted. Three districts of WMMA were chosen as the study areas. We summarized previous published data and sampled 14 typical soil profiles to analyze the spatial and vertical distributions of Hg in soil in the study areas. The regional geologic background, direct and indirect Hg deposition, and Hg-polluted irrigation water were considered as the main sources of Hg contaminations in local soils. Furthermore, the enrichment factor (EF) method was applied to assess the extent of anthropogenic input of Hg to soil. Titanium (Ti) was chosen to be the reference element to calculate the EF. Generally, the elevated values of EF were observed in the upper soil layers and close to mine wastes. The total budget of Hg in soil contributed from anthropogenic sources was estimated to be 1,227 t in arable soil and 75 t in natural soil. Our data showed that arable soil was the major sink of anthropogenic Hg in the study area.

  18. A 60-year sedimentary record of natural and anthropogenic impacts on Lake Chenghai, China.

    PubMed

    Zan, Fengyu; Huo, Shouliang; Xi, Beidou; Zhang, Jingtian; Liao, Haiqing; Wang, Yue; Yeager, Kevin M

    2012-01-01

    Recent sediments from Lake Chenghai, China, were investigated at high temporal resolution to trace both natural and anthropogenic effects on the lake using total organic carbon (TOC), total nitrogen (TN), total phosphorus (TP), organic phosphorus (Po), inorganic phosphorus (Pi) and organic carbon and nitrogen stable isotopes (delta13Corg and delta15N) in a 137Cs-dated sediment core. The results indicated that the sedimentary record covers the last 60 years, during which the lake had undergone apparent changes in nutrient sources and productivity in response to nutrient loading. Prior to the late 1980s, the nutrient contents in sediments mainly originated from algae and lake productivity was relatively stable. Since the late 1980s, increasing TOC, TN and TP concentrations together with the change of delta13Corg and delta15N suggested anthropogenic perturbations in nutrient loading and lake productivity. Endogenic nutrients derived from algae and anthropogenic inputs were two important sources of sedimentary nutrients. The anthropogenic nutrients mainly originated from the discharge of industrial wastewater and artificial cultivation of Spirulina after the middle 1980s, and domestic wastewater discharged from Yongsheng County since 1993.

  19. Seasonal variability in anthropogenic halocarbon emissions.

    PubMed

    Gentner, Drew R; Miller, Angela M; Goldstein, Allen H

    2010-07-15

    Ambient concentrations of eight predominantly anthropogenic halocarbons were measured via in situ gas chromatography in California's South Coast air basin for both summer and fall during the 2005 Study of Organic Aerosols at Riverside (SOAR). Ongoing emissions of the banned halocarbons methylchloroform and CFC-11 were observed in the South Coast air basin, whereas CFC-113 emissions have effectively ceased. We estimate anthropogenic emissions in the South Coast air basin for methylchloroform, CFC-11, HCFC-141b, chloroform, tetrachloroethene (PCE), trichloroethylene (TCE), and dichloromethane based on regressions of halocarbon to carbon monoxide mixing ratios and carbon monoxide emission inventories. We estimate per capita methylchloroform and chloroform emissions in the South Coast air basin for the year 2005 to be 6.6 +/- 0.4 g/(person.year) and 19 +/- 1 g/(person.year), respectively. We compare our results to national emission estimates calculated from previous work; for several compounds, emissions in the South Coast air basin are significantly lower than national per capita emissions. We observed strong seasonal differences in anthropogenic emissions of methylchloroform and chloroform; emissions were 4.5 and 2.5 times greater in summer than in fall, respectively. Possible seasonal sources include landfills and water chlorination. We conclude that seasonal variability in methylchloroform emissions has not been included in previous inventories and may cause errors in methylchloroform emission estimates after the year 2000 and seasonally resolved inversion calculations of hydroxyl radical abundance.

  20. Exploring the engine of anthropogenic iron cycles

    PubMed Central

    Müller, Daniel B.; Wang, Tao; Duval, Benjamin; Graedel, T. E.

    2006-01-01

    Stocks of products in use are the pivotal engines that drive anthropogenic metal cycles: They support the lives of people by providing services to them; they are sources for future secondary resources (scrap); and demand for in-use stocks generates demand for metals. Despite their great importance and their impacts on other parts of the metal cycles and the environment, the study of in-use stocks has heretofore been widely neglected. Here we investigate anthropogenic and geogenic iron stocks in the United States (U.S.) by analyzing the iron cycle over the period 1900–2004. Our results show the following. (i) Over the last century, the U.S. iron stock in use increased to 3,200 Tg (million metric tons), which is the same order of magnitude as the remaining U.S. iron stock in identified ores. On a global scale, anthropogenic iron stocks are less significant compared with natural ores, but their relative importance is increasing. (ii) With a perfect recycling system, the U.S. could substitute scrap utilization for domestic mining. (iii) The per-capita in-use iron stock reached saturation at 11–12 metric tons in ≈1980. This last finding, if applicable to other economies as well, could allow a significant improvement of long-term forecasting of steel demand and scrap availability in emerging market economies and therefore has major implications for resource sustainability, recycling technology, and industrial and governmental policy. PMID:17053079

  1. Are torpid bats immune to anthropogenic noise?

    PubMed

    Luo, Jinhong; Clarin, B-Markus; Borissov, Ivailo M; Siemers, Björn M

    2014-04-01

    Anthropogenic noise has a negative impact on a variety of animals. However, many bat species roost in places with high levels of anthropogenic noise. Here, we tested the hypothesis that torpid bats are insensitive to anthropogenic noise. In a laboratory experiment, we recorded skin temperature (Tsk) of bats roosting individually that were subjected to playbacks of different types of noise. We found that torpid bats with Tsk ~10°C lower than their active Tsk responded to all types of noise by elevating Tsk. Bats responded most strongly to colony and vegetation noise, and most weakly to traffic noise. The time of day when torpid bats were exposed to noise had a pronounced effect on responses. Torpid bats showed increasing responses from morning towards evening, i.e. towards the onset of the active phase. Skin temperature at the onset of noise exposure (Tsk,start, 17-29°C) was not related to the response. Moreover, we found evidence that torpid bats rapidly habituated to repeated and prolonged noise exposure.

  2. Anthropogenic transformation of the terrestrial biosphere.

    PubMed

    Ellis, Erle C

    2011-03-13

    Human populations and their use of land have transformed most of the terrestrial biosphere into anthropogenic biomes (anthromes), causing a variety of novel ecological patterns and processes to emerge. To assess whether human populations and their use of land have directly altered the terrestrial biosphere sufficiently to indicate that the Earth system has entered a new geological epoch, spatially explicit global estimates of human populations and their use of land were analysed across the Holocene for their potential to induce irreversible novel transformation of the terrestrial biosphere. Human alteration of the terrestrial biosphere has been significant for more than 8000 years. However, only in the past century has the majority of the terrestrial biosphere been transformed into intensively used anthromes with predominantly novel anthropogenic ecological processes. At present, even were human populations to decline substantially or use of land become far more efficient, the current global extent, duration, type and intensity of human transformation of ecosystems have already irreversibly altered the terrestrial biosphere at levels sufficient to leave an unambiguous geological record differing substantially from that of the Holocene or any prior epoch. It remains to be seen whether the anthropogenic biosphere will be sustained and continue to evolve.

  3. Blue whales respond to anthropogenic noise.

    PubMed

    Melcón, Mariana L; Cummins, Amanda J; Kerosky, Sara M; Roche, Lauren K; Wiggins, Sean M; Hildebrand, John A

    2012-01-01

    Anthropogenic noise may significantly impact exposed marine mammals. This work studied the vocalization response of endangered blue whales to anthropogenic noise sources in the mid-frequency range using passive acoustic monitoring in the Southern California Bight. Blue whales were less likely to produce calls when mid-frequency active sonar was present. This reduction was more pronounced when the sonar source was closer to the animal, at higher sound levels. The animals were equally likely to stop calling at any time of day, showing no diel pattern in their sensitivity to sonar. Conversely, the likelihood of whales emitting calls increased when ship sounds were nearby. Whales did not show a differential response to ship noise as a function of the time of the day either. These results demonstrate that anthropogenic noise, even at frequencies well above the blue whales' sound production range, has a strong probability of eliciting changes in vocal behavior. The long-term implications of disruption in call production to blue whale foraging and other behaviors are currently not well understood.

  4. Climate response to indirect anthropogenic sulfate forcing

    SciTech Connect

    Erickson, D.J.; Oglesby, R.J.; Marshall, S.

    1995-08-01

    A general circulation model (GCM) has been used to conduct sensitivity tests of the climatic influence imparted by a cloud albedo change hypothesized to result from anthropogenic increases in atmospheric sulfur. The global distribution of anthropogenic sulfate aerosols is computed with a simplified 3-D transport model. The NCAR CCM1 has been run with a cloud albedo perturbation that is a function of the distribution of anthropegenic sulfur particles. The authors report climate statistics from the last 20 years of 30 year GCM control and experiment runs. The climate response is strongest in the northern hemisphere winter, with cooling over the North Atlantic and North Pacific oceans on the order of 2-6{degrees}C. The 500 mb geopotential height field shows a significant deepening over the Canadian provinces, enhancing the northernly flow over the North American and North Atlantic regions during boreal winter. The equilibrium climate does not, however, cool over central Europe in northern hemisphere winter, despite this region being one of the most heavily impacted areas in the world by sulfate aerosol. The anthropogenic sulfate {open_quotes}indirect{close_quotes} forcing elicits a highly non-linear climate response that can be explained through changes in the hemispheric wave train. These results may assist in explaining the long-standing climate change issue of what causes the cooling over the North Atlantic and North Pacific over the last decades, a feature that is not explained by increases in greenhouse gases alone. 18 refs., 4 figs.

  5. Anthropogenic aerosol forcing of Atlantic tropical storms

    NASA Astrophysics Data System (ADS)

    Dunstone, N. J.; Smith, D. M.; Booth, B. B. B.; Hermanson, L.; Eade, R.

    2013-07-01

    The frequency of tropical storms in the North Atlantic region varies markedly on decadal timescales, with profound socio-economic impacts. Climate models largely reproduce the observed variability when forced by observed sea surface temperatures. However, the relative importance of natural variability and external influences such as greenhouse gases, dust, sulphate and volcanic aerosols on sea surface temperatures, and hence tropical storms, is highly uncertain. Here, we assess the effect of individual climate drivers on the frequency of North Atlantic tropical storms between 1860 and 2050, using simulations from a collection of climate models. We show that anthropogenic aerosols lowered the frequency of tropical storms over the twentieth century. However, sharp declines in anthropogenic aerosol levels over the North Atlantic at the end of the twentieth century allowed the frequency of tropical storms to increase. In simulations with a model that comprehensively incorporates aerosol effects (HadGEM2-ES; ref. ), decadal variability in tropical storm frequency is well reproduced through aerosol-induced north-south shifts in the Hadley circulation. However, this mechanism changes in future projections. Our results raise the possibility that external factors, particularly anthropogenic aerosols, could be the dominant cause of historical tropical storm variability, and highlight the potential importance of future changes in aerosol emissions.

  6. Blue Whales Respond to Anthropogenic Noise

    PubMed Central

    Melcón, Mariana L.; Cummins, Amanda J.; Kerosky, Sara M.; Roche, Lauren K.; Wiggins, Sean M.; Hildebrand, John A.

    2012-01-01

    Anthropogenic noise may significantly impact exposed marine mammals. This work studied the vocalization response of endangered blue whales to anthropogenic noise sources in the mid-frequency range using passive acoustic monitoring in the Southern California Bight. Blue whales were less likely to produce calls when mid-frequency active sonar was present. This reduction was more pronounced when the sonar source was closer to the animal, at higher sound levels. The animals were equally likely to stop calling at any time of day, showing no diel pattern in their sensitivity to sonar. Conversely, the likelihood of whales emitting calls increased when ship sounds were nearby. Whales did not show a differential response to ship noise as a function of the time of the day either. These results demonstrate that anthropogenic noise, even at frequencies well above the blue whales' sound production range, has a strong probability of eliciting changes in vocal behavior. The long-term implications of disruption in call production to blue whale foraging and other behaviors are currently not well understood. PMID:22393434

  7. δ15N as a proxy for historic anthropogenic nitrogen loading in Charleston Harbor, SC, USA

    NASA Astrophysics Data System (ADS)

    Payne, T. N.; Andrus, C. F. T.

    2015-12-01

    Bivalve shell geochemistry can serve as a useful indicator of changes in coastal environments. There is increasing interest in developing paleoenvironmental proxies from mollusk shell organic components. Numerous studies have focused on how the δ15N obtained from bivalve tissues can be used to trace present-day wastewater input into estuaries. However, comparatively little attention has been paid to tracing the impact of anthropogenic nitrogen loading into estuaries over time. By measuring historic levels of δ15N in the organic fraction of oyster shells (Crassostrea virginica) from archaeological sites around Charleston Harbor and comparing those levels to the δ15N content of modern shells, it is possible to assess how nitrogen has fluctuated historically in the area. Whole-shell samples from the Late Archaic Period (~3000-4000 BP, Late Woodland Period (~1400-800 BP), 18th and 19th centuries, and modern controls were measured for %N and d15N. Evidence of increased anthropogenic input of N is expected to begin in the early historic period based on similar analysis in Chesapeake Bay. More ancient samples may give insight into baseline conditions prior to recent population growth and industrialization. This information could help understand how large-scale anthropogenic nitrogen loading has affected coastal ecosystems over time and guide future remediation. Furthermore, this project will help refine and improve this novel proxy of past environmental conditions.

  8. Modulation of snow reflectance and snowmelt from Central Asian glaciers by anthropogenic black carbon

    PubMed Central

    Schmale, Julia; Flanner, Mark; Kang, Shichang; Sprenger, Michael; Zhang, Qianggong; Guo, Junming; Li, Yang; Schwikowski, Margit; Farinotti, Daniel

    2017-01-01

    Deposited mineral dust and black carbon are known to reduce the albedo of snow and enhance melt. Here we estimate the contribution of anthropogenic black carbon (BC) to snowmelt in glacier accumulation zones of Central Asia based on in-situ measurements and modelling. Source apportionment suggests that more than 94% of the BC is emitted from mostly regional anthropogenic sources while the remaining contribution comes from natural biomass burning. Even though the annual deposition flux of mineral dust can be up to 20 times higher than that of BC, we find that anthropogenic BC causes the majority (60% on average) of snow darkening. This leads to summer snowmelt rate increases of up to 6.3% (7 cm a−1) on glaciers in three different mountain environments in Kyrgyzstan, based on albedo reduction and snowmelt models. PMID:28079148

  9. Modulation of snow reflectance and snowmelt from Central Asian glaciers by anthropogenic black carbon

    NASA Astrophysics Data System (ADS)

    Schmale, Julia; Flanner, Mark; Kang, Shichang; Sprenger, Michael; Zhang, Qianggong; Guo, Junming; Li, Yang; Schwikowski, Margit; Farinotti, Daniel

    2017-01-01

    Deposited mineral dust and black carbon are known to reduce the albedo of snow and enhance melt. Here we estimate the contribution of anthropogenic black carbon (BC) to snowmelt in glacier accumulation zones of Central Asia based on in-situ measurements and modelling. Source apportionment suggests that more than 94% of the BC is emitted from mostly regional anthropogenic sources while the remaining contribution comes from natural biomass burning. Even though the annual deposition flux of mineral dust can be up to 20 times higher than that of BC, we find that anthropogenic BC causes the majority (60% on average) of snow darkening. This leads to summer snowmelt rate increases of up to 6.3% (7 cm a‑1) on glaciers in three different mountain environments in Kyrgyzstan, based on albedo reduction and snowmelt models.

  10. Stable lead isotopic ratios trace thermohaline circulation in the subarctic North Atlantic

    NASA Astrophysics Data System (ADS)

    Véron, A. J.; Church, T. M.; Rivera-Duarte, I.; Flegal, A. R.

    Vertical profiles of lead concentrations in the subarctic North Atlantic attest to the predominance of anthropogenic lead inputs to those waters, while variations in their lead isotopic ratios ( 204Pb : 206Pb : 207Pb : 208Pb) show the multiplicity of those industrial lead inputs. Spatial gradients in the isotopic ratios are consistent with the thermohaline circulation of different water masses, which seemingly have relatively discrete isotopic signatures. These include characteristic 206Pb/ 207Pb ratios of the North Atlantic Drift (1.183-1.187), Iceland-Scotland Overflow Water (1.173-1.176), Denmark Straits Overflow Water (1.179-1.182), and Labrador Sea Water (1.190-1.120). Based on parallels between these initial isotopic data and T- S measurements, it is proposed that stable lead isotopic compositions may be employed as complementary tracers of the mixing of source waters in the Nordic seas, as they overflow the Iceland-Scotland Ridge and Denmark Strait, mixing into the Labrador Sea to form North Atlantic Deep Water.

  11. Indicating anthropogenic effectson urban water system - indicators and extension

    NASA Astrophysics Data System (ADS)

    Strauch, G.; Ufz-Team

    2003-04-01

    Urban water systems are polluted by diffusive and direct contribution of anthropogenic activities. Besides industrial contaminants like aromatic and chlorinated HC and other persistent organic compounds, the urban aquatic environment is increasingly polluted by low concentrated but high eco-toxic compounds as pharmaceuticals, fragrances, plasticizers which most have disrupt endocrine functions, and trace elements carried in by surface and sub-surface waste water and seeping processes. This contamination could have a longtime impact on the urban ecosystem and on the human health. The interdisciplinary project on risk assessment of water pollution was initiated to explore new methodologies for assessing human activities on the urban water system and processes among urban watersheds. In a first assumption we used a flow model concept with in- and output and surface water transport represented by the city of Halle, Germany, and the river Saale. The river Saale acts as surface water system collecting waste water inputs along the city traverse. We investigated the anthropogenic effect on the urban water system using the indicators hydrological parameters, compound specific pattern of complex organic substances and trace elements, isotopic signatures of water (H, O) and dissolved substances (sulfate, DIC, nitrate), pathogens, and microbiota. A first balance modeling showed that main ions are not very sensitive concerning the direct urban input into the river. Depending on the discharge of the river in high and low flood stages the load of dissolved matter has no specific urban effect. However, the concentration pattern of fragrances (tonalid, galaxolid) and endocrine disrupters (t-nonylphenol) point to a different pollution along the city traverse: downstream of the sewage plant a higher load was observed in comparison to the upstream passage. Furthermore, a degradation ability of fungi and bacteria occurred in the bank sediments could be detected in lab experiments

  12. Anthropogenic features and hillslope processes interaction

    NASA Astrophysics Data System (ADS)

    Tarolli, Paolo; Sofia, Giulia

    2016-04-01

    Topography emerges as a result of natural driving forces, but some human activities (such as mining, agricultural practices and the construction of road networks) directly or indirectly move large quantities of soil, which leave clear topographic signatures embedded on the Earth's morphology. These signatures can cause drastic changes to the geomorphological organization of the landscape, with direct consequences on Earth surface processes (Tarolli and Sofia, 2016). To this point, the present research investigates few case studies highlighting the influences of anthropogenic topographic signatures on hillslope processes, and it shows the effectiveness of High-Resolution Topography (HRT) derived from the recent remote sensing technologies (e.g. lidar, satellite, structure from motion photogrammetry), to better understand this interaction. The first example is related to agricultural terraces. In recent times, terraced areas acquired a new relevance to modern concerns about erosion and land instability, being the agricultural land mostly threatened by abandonment or intensification and specialization of agriculture, resulting in more landslide-prone bench terraces, or heavy land levelling with increased erosion. The second case study discusses about the role of agricultural and forest roads on surface erosion and landslides. The third case study investigates geomorphic processes in an open pit mine. In all case studies, HRT served as the basis for the development of new methodologies able to recognize and analyze changes on Earth surface processes along hillslopes. The results show how anthropogenic elements have crucial effects on sediment production and sediment delivery, also influencing the landscape connectivity. The availability of HRT can improve our ability to actually model anthropogenic morphologies, quantify them, and analyse the links between anthropogenic elements and geomorphic processes. The results presented here, and the creation and dissemination of

  13. Anthropogenic Nutrient Loading in the Northeastern US 1920-2000

    NASA Astrophysics Data System (ADS)

    Hale, R. L.; Ng, M.; Brideau, J. M.; Hoover, J. H.; Thomas, B.

    2010-12-01

    Human activities have dramatically altered biogeochemical cycles on local to global scales. Altered fluxes of nutrients (nitrogen, phosphorus) to freshwater systems have been driven directly by human-mediated fluxes (e.g., industrial N fixation) and indirectly due to changes in land and water systems that alter rates of biogeochemical transformations and transport vectors for nutrients. The Northeastern United States as a region underwent many biophysical and political changes over the 20th century, making it an excellent case study for understanding human-biogeochemical relationships over time. From 1920 to 2000, this region experienced significant losses of agricultural land and increases in forest and urban land cover. Furthermore, major national and state legislation, including nuisance laws and the Clean Water Act, was passed during the 20th century to control pollution problems, and major technological advances in wastewater treatment were made. Our goals were to: 1) describe quantitative changes in the spatial patterns of water quality over time, 2) understand the proximate (e.g., changes in land use, new technology) and 3) ultimate (e.g., major demographic, economic, social shifts) drivers of those patterns. Using data from the historic Census of Agriculture, the National Atmospheric Deposition Program, and primary literature, we create a comprehensive time series database of anthropogenic N and P inputs to the Northeast terrestrial system. Inputs are estimated for each county at decadal time scales. Inputs included atmospheric deposition of nitrogen, fertilizer, manure, enhanced biological nitrogen fixation, and domestic waste. We used this database, in conjunction with data on land use, reservoirs, climate, and stream nutrient loads estimated from USGS NWIS to develop a modified export coefficient model for 26 watersheds in the Northeast. We then used this model to estimate nutrient loads at the decadal scale for all HUC 8 watersheds in our study region

  14. A new global anthropogenic heat estimation based on high-resolution nighttime light data.

    PubMed

    Yang, Wangming; Luan, Yibo; Liu, Xiaolei; Yu, Xiaoyong; Miao, Lijuan; Cui, Xuefeng

    2017-08-22

    Consumption of fossil fuel resources leads to global warming and climate change. Apart from the negative impact of greenhouse gases on the climate, the increasing emission of anthropogenic heat from energy consumption also brings significant impacts on urban ecosystems and the surface energy balance. The objective of this work is to develop a new method of estimating the global anthropogenic heat budget and validate it on the global scale with a high precision and resolution dataset. A statistical algorithm was applied to estimate the annual mean anthropogenic heat (AH-DMSP) from 1992 to 2010 at 1×1 km(2) spatial resolution for the entire planet. AH-DMSP was validated for both provincial and city scales, and results indicate that our dataset performs well at both scales. Compared with other global anthropogenic heat datasets, the AH-DMSP has a higher precision and finer spatial distribution. Although there are some limitations, the AH-DMSP could provide reliable, multi-scale anthropogenic heat information, which could be used for further research on regional or global climate change and urban ecosystems.

  15. REL - English Bulk Data Input.

    ERIC Educational Resources Information Center

    Bigelow, Richard Henry

    A bulk data input processor which is available for the Rapidly Extensible Language (REL) English versions is described. In REL English versions, statements that declare names of data items and their interrelationships normally are lines from a terminal or cards in a batch input stream. These statements provide a convenient means of declaring some…

  16. Inputs for L2 Acquisition.

    ERIC Educational Resources Information Center

    Saleemi, Anjum P.

    1989-01-01

    Major approaches of describing or examining linguistic data from a potential target language (input) are analyzed for adequacy in addressing the concerns of second language learning theory. Suggestions are made for making the best of these varied concepts of input and for reformulation of a unified concept. (MSE)

  17. Input in Second Language Acquisition.

    ERIC Educational Resources Information Center

    Gass, Susan M., Ed.; Madden, Carolyn G., Ed.

    This collection of conference papers includes: "When Does Teacher Talk Work as Input?"; "Cultural Input in Second Language Learning"; "Skilled Variation in a Kindergarten Teacher's Use of Foreigner Talk"; "Teacher-Pupil Interaction in Second Language Development"; "Foreigner Talk in the University…

  18. Input in Second Language Acquisition.

    ERIC Educational Resources Information Center

    Gass, Susan M., Ed.; Madden, Carolyn G., Ed.

    This collection of conference papers includes: "When Does Teacher Talk Work as Input?"; "Cultural Input in Second Language Learning"; "Skilled Variation in a Kindergarten Teacher's Use of Foreigner Talk"; "Teacher-Pupil Interaction in Second Language Development"; "Foreigner Talk in the University…

  19. Anthropogenic Aerosol Effects on Sea Surface Temperatures: Mixed-Layer Ocean Experiments with Explicit Aerosol Representation

    NASA Astrophysics Data System (ADS)

    Dallafior, Tanja; Folini, Doris; Wild, Martin; Knutti, Reto

    2014-05-01

    Anthropogenic aerosols affect the Earth's radiative balance both through direct and indirect effects. These effects can lead to a reduction of the incoming solar radiation at the surface, i.e. dimming, which may lead to a change in sea surface temperatures (SST) or SST pattern. This, in turn, may affect precipitation patterns. The goal of the present work is to achieve an estimate of the equilibrium SST changes under anthropogenic aerosol forcing since industrialisation. We show preliminary results from mixed-layer ocean (MLO) experiments with explicit aerosol representation performed with ECHAM6-HAM. The (fixed) MLO heat flux into the deep ocean was derived from atmosphere only runs with fixed climatological SSTs (1961-1990 average) and present day (year 2000) aerosols and GHG burdens. Some experiments we repeated with an alternative MLO deep ocean heat flux (based on pre-industrial conditions) to test the robustness of our results with regard to this boundary condition. The maximum surface temperature responses towards anthropogenic aerosol and GHG forcing (separately and combined) were derived on a global and regional scale. The same set of experiments was performed with aerosol and GHG forcings representative of different decades over the past one and a half centuries. This allows to assess how SST patterns at equilibrium changed with changing aerosol (and GHG) forcing. Correlating SST responses with the change in downward clear-sky and all-sky shortwave radiation provides a first estimate of the response to anthropogenic aerosols. Our results show a clear contrast in hemispheric surface temperature response, as expected from the inter-hemispheric asymmetry of aerosol forcing The presented work is part of a project aiming at quantifying the effect of anthropogenic aerosol forcing on SSTs and the consequences for global precipitation patterns. Results from this study will serve as a starting point for further experiments involving a dynamic ocean model, which

  20. Possible Influence of Anthropogenic Aerosols on Cirrus Clouds and Anthropogenic Forcing

    SciTech Connect

    Penner, Joyce E.; Chen, Yang; Wang, Minghuai; Liu, Xiaohong

    2009-02-03

    Cirrus clouds have a net warming effect on the atmosphere and cover about 30% of the Earth’s area. Aerosol particles initiate ice formation in the upper troposphere through modes of action that include homogeneous freezing of solution droplets, heterogeneous nucleation on solid particles immersed in a solution, and deposition nucleation of vapor onto solid particles. Here, we examine the possible change in ice number concentration from anthropogenic soot originating from surface sources of fossil fuel and biomass burning, from anthropogenic sulfate aerosols, and from aircraft that deposit their aerosols directly in the upper troposphere. We find that fossil fuel and biomass burning soot aerosols exert a radiative forcing of -0.68 to 0.01 Wm-2 while anthropogenic sulfate aerosols exert a forcing of -0.01 to 0.18 Wm-2. Our calculations show that the sign of the forcing by aircraft soot depends on the model configuration and can be both positive or negative, ranging from -0.16 to 0.02 Wm-2. The magnitude of the forcing in cirrus clouds can be comparable to the forcing exerted by anthropogenic aerosols on warm clouds, but this forcing has not been included in past assessments of the total anthropogenic radiative forcing of climate.

  1. Lead Poisoning

    MedlinePlus

    Lead is a metal that occurs naturally in the earth's crust. Lead can be found in all parts of our ... from human activities such as mining and manufacturing. Lead used to be in paint; older houses may ...

  2. Rarity Value and Species Extinction: The Anthropogenic Allee Effect

    PubMed Central

    Courchamp, Franck; Signoret, Laetitia; Bull, Leigh; Meinard, Yves

    2006-01-01

    Standard economic theory predicts that exploitation alone is unlikely to result in species extinction because of the escalating costs of finding the last individuals of a declining species. We argue that the human predisposition to place exaggerated value on rarity fuels disproportionate exploitation of rare species, rendering them even rarer and thus more desirable, ultimately leading them into an extinction vortex. Here we present a simple mathematical model and various empirical examples to show how the value attributed to rarity in some human activities could precipitate the extinction of rare species—a concept that we term the anthropogenic Allee effect. The alarming finding that human perception of rarity can precipitate species extinction has serious implications for the conservation of species that are rare or that may become so, be they charismatic and emblematic or simply likely to become fashionable for certain activities. PMID:17132047

  3. Plant ecology. Anthropogenic environmental changes affect ecosystem stability via biodiversity.

    PubMed

    Hautier, Yann; Tilman, David; Isbell, Forest; Seabloom, Eric W; Borer, Elizabeth T; Reich, Peter B

    2015-04-17

    Human-driven environmental changes may simultaneously affect the biodiversity, productivity, and stability of Earth's ecosystems, but there is no consensus on the causal relationships linking these variables. Data from 12 multiyear experiments that manipulate important anthropogenic drivers, including plant diversity, nitrogen, carbon dioxide, fire, herbivory, and water, show that each driver influences ecosystem productivity. However, the stability of ecosystem productivity is only changed by those drivers that alter biodiversity, with a given decrease in plant species numbers leading to a quantitatively similar decrease in ecosystem stability regardless of which driver caused the biodiversity loss. These results suggest that changes in biodiversity caused by drivers of environmental change may be a major factor determining how global environmental changes affect ecosystem stability.

  4. Trace metals inputs in the Adour estuary, southwestern france: upstream versus local sources

    NASA Astrophysics Data System (ADS)

    Point, D.; Bareille, G.; Amouroux, D.; Stoichev, T.; Donard, O.

    2003-04-01

    Estuarine systems play a major role in the distribution, transport and fate of heavy metals. The contamination of number of estuarine environments in the Atlantic Europe has largely been studied, especially by determining the gross inputs of contaminants by their watersheds and by studying the behavior of metals in the mixing zone between fresh and salt waters where complex physical, chemical and biological processes occurs. However, in urban and industrialized estuaries source-specific information, including sewage effluents, industrial discharges, urban runoff, combined sewer overflows, is lacking. The Adour hydrosystem (southwestern, France) is poorly known. The estuarine part is characterized by an important anthropogenic pressure close to its mouth with large urban and industrial activities ending to important inputs of contaminants such as trace metals. An environmental assessment program was purchased to evaluate and quantify the anthropogenic pressure on the Adour estuary ecosystem. A total of 25 anthropogenic sources entering the estuarine mixing zone have been followed towards 4 campaigns along 2001 and 2002. On each stations both dissolved and particulate fractions were analyzed for trace elements (Cd, Cu, Zn, Pb) and organic carbon (OC) according to clean procedures for each effluent. Trace metal concentrations were combined with discharge flow measurements to establish anthropogenic net fluxes to the estuarine environment. These fluxes are compared with upstream inputs from the whole drainage basin and discussed in terms of specific contaminants/anthropogenic source identification. Specific data treatment approach allows the possibility to trace effluent source and origin ending to a classification. Specific periods focused in that study reflects well the influence and the anthropogenic impact into the estuary during dry weather conditions (summer) which combined to low discharge condition are the most unfavourable conditions ending to a maximum impact

  5. Impact of Anthropogenic CO2 on the Next Glacial Cycle

    NASA Astrophysics Data System (ADS)

    Herrero, C.; García-Olivares, A.; Pelegrí, J. L.

    2014-12-01

    A simple relaxation-type model (García-Olivares and Herrero, 2013) based on an optimization of Paillard and Parrenin (2004), has been used to predict the future evolution of atmospheric CO2, global ice volume and Antarctic ice cover during the next 300 kyr, with and without the atmospheric CO2 perturbation caused by anthropogenic emissions.The initial atmospheric CO2 condition is obtained after a critical data analysis that sets 1300 Gt as the most realistic carbon Ultimate Recoverable Resources, with the help of a global compartmental model to determine the carbon transfer function to the atmosphere. This analysis sets a peak of emissions on year 2037 AD and a maximum CO2 concentration of 519 ppmv in 2300 AD, leading to 20 kyr of abnormally high greenhouse effect. Weathering compensation and emission of methane from clathrates have also been considered as they have relevant effects on the dynamics of the system after the perturbation.The anthropogenic CO2 pulse clearly perturbs the natural cycle for all model variables during the forthcoming 300 kyr. The present interglacial will be lengthen by 25 kyr, as the anthropogenic perturbation will lead to a delay in the future advance of the ice sheet on the Antarctic shelf and a consequent perturbation of the deep ocean stratification, so the relative maximum of boreal insolation 65 kyr AP will not affect the developing glaciation. Instead, it will be the following insolation peak, about 110 kyr AP, which will find an appropriate climatic state to trigger the next deglaciation. The next glacial maximum will take place about 105 kyr AP and the following interglacial will be delayed forward in time by 44 kyr in relation to unperturbed conditions.This study endorses the idea that relaxation type coupled models, despite their simple structure, may retain the principal Earth's climatic interactions, being capable of accounting for the natural evolution of an externally imposed atmospheric CO2 pulse. - Garcia-Olivares, A

  6. Economic impacts of anthropogenic activities on coastlines of the United States

    USGS Publications Warehouse

    Magoon, Orville T.; Williams, S. Jeffress; Lent, Linda K.; Richmond, James A.; Treadwell, Donald D.; Douglass, Scott L.; Edge, Billy L.; Ewing, Lesley C.; Pratt, Anthony P.

    2004-01-01

    Anthropogenic activities primarily impact coasts by reducing sediment inputs, altering sediment transport processes, and accelerating sediment losses to the offshore. These activities include: sand and gravel extraction, navigation and shore protection works; non-structural shoreline management strategies such as beach nourishment, sand by-passing and beach scraping, dams and flood control works; channel and inlet dredging; subsidence caused by fluid extraction and reduction of carbonate beach material. Although many of these activities have improved the quality of life, they also have had unintended effects on the coast. The issues that arise from human alterations of the coast are common to many coastal regions around the world; this paper draws from several areas of the United States to present an overview and provisional assessment of the economic consequences of anthropogenic activities along the Pacific coast.

  7. Are seagrass beds indicators of anthropogenic nutrient stress in the rocky intertidal?

    PubMed

    Honig, Susanna E; Mahoney, Brenna; Glanz, Jess S; Hughes, Brent B

    2017-01-15

    It is well established that anthropogenic nutrient inputs harm estuarine seagrasses, but the influence of nutrients in rocky intertidal ecosystems is less clear. In this study, we investigated the effect of anthropogenic nutrient loading on Phyllospadix spp., a rocky intertidal seagrass, at local and regional scales. At sites along California, Washington, and Oregon, we demonstrated a significant, negative correlation of urban development and Phyllospadix bed thickness. These results were echoed locally along an urban gradient on the central California coast, where Phyllospadix shoot δ(15)N was negatively associated with Phyllospadix bed thickness, and experimentally, where nutrient additions in mesocosms reduced Phyllospadix shoot formation and increased epiphytic cover on Phyllospadix shoots. These findings provide evidence that coastal development can threaten rocky intertidal seagrasses through increased epiphytism. Considering that seagrasses provide vital ecosystem services, mitigating eutrophication and other factors associated with development in the rocky intertidal coastal zone should be a management priority. Copyright © 2016 Elsevier Ltd. All rights reserved.

  8. Dynamics of Aromatase and Physiological Indexes in Male Fish as Potential Biomarkers of Anthropogenic Pollution.

    PubMed

    Guyón, N F; Roggio, M A; Amé, M V; Wunderlin, D A; Bistoni, M A

    2016-11-01

    Endocrine disruption on aquatic wildlife is being increasingly reported, and the changes in gene aromatase expression are used as indicators. However, natural fluctuations in brain and gonadal aromatase expression and physiological indexes have not been previously measured in a fish species (Jenynsia multidentata) throughout a complete reproductive cycle, nor the biological effects of anthropogenic inputs on these responses. Accordingly, males were monthly collected over a year in both, a reference and a contaminated site. Physicochemical analyses of water samples were done and reflected a strong anthropogenic impact. Brain aromatase fluctuates along the reproductive cycle of this species and, noticeably, the increase of brain gene expression begins with a 1 month delay in the contaminated site. This mismatch is also evidenced for testes weight. Hepatosomatic index also revealed adverse effects in the polluted site. In turn, the alterations observed in biological responses could be affecting the reproduction of this fish species.

  9. Abnormal mortality of octopus after a storm water event: Accumulated lead and lead isotopes as fingerprints.

    PubMed

    Raimundo, J; Ruano, F; Pereira, J; Mil-Homens, M; Brito, P; Vale, C; Caetano, M

    2017-03-01

    Octopus vulgaris is a sedentary organism that inhabits coastal waters being exposed to anthropogenic compounds. Lead concentration in coastal environments reflects many processes and activities namely weathering, industrial and domestic discharges, and atmospheric deposition. Since lead isotopic composition is little affected by kinetic processes occurring between source and sink, its signature has been used to identify different Pb sources. After a short-term heavy rainfall, hundreds of octopus appeared dead in two Portuguese coastal areas. Histopathology and Pb levels and its stable isotopes were determined in tissues, such as digestive gland, of stranded octopus and compared to alive specimens, sediments and runoff material from the same areas. Histology results showed severe damage in stranded octopus tissues suggesting that death was probably associated to multiple organ failure linked to hypertrophy and exudates input. In addition, Pb in stranded specimens reach concentrations up to one order of magnitude above the levels reported for alive octopus. Pb isotopic signatures in stranded organisms were closer to runoff material pointing to a similar origin of Pb. In summary, the results in this study showed that a short-term runoff event might change abruptly the salinity leading to the disruption of the osmoregulation function of octopus and consequently leading to its death. The analyses of stable isotopic Pb signature in octopus tissues corroborate these results and points to a change in the Pb source due to runoff after the storm water event. Pb stable isotopes in octopus proved to be an adequate tool to confirm the cause of death and linking it to the environment conditions.

  10. Lead poisoning

    SciTech Connect

    Rekus, J.F.

    1992-08-01

    Construction workers who weld, cut or blast structural steel coated with lead-based paint are at significant risk of lead poisoning. Although technology to control these exposures may not have existed when the lead standard was promulgated, it is available today. Employers who do not take steps to protect their employees from lead exposure may be cited and fined severely for their failure.

  11. Input management of production systems.

    PubMed

    Odum, E P

    1989-01-13

    Nonpoint sources of pollution, which are largely responsible for stressing regional and global life-supporting atmosphere, soil, and water, can only be reduced (and ultimately controlled) by input management that involves increasing the efficiency of production systems and reducing the inputs of environmentally damaging materials. Input management requires a major change, an about-face, in the approach to management of agriculture, power plants, and industries because the focus is on waste reduction and recycling rather than on waste disposal. For large-scale ecosystem-level situations a top-down hierarchical approach is suggested and illustrated by recent research in agroecology and landscape ecology.

  12. Linking terrestrial P inputs to riverine export across the United ...

    EPA Pesticide Factsheets

    Human beings have greatly accelerated phosphorus (P) flows from land to aquatic ecosystems, often resulting in eutrophication, harmful algal blooms, and hypoxia. Although a variety of statistical and mechanistic models have been used to explore the relationship between terrestrial nutrient management and losses to waterways, our understanding of how natural and anthropogenic landscape characteristics mediate losses of P from watersheds lags behind that of nitrogen. The need for higher resolution data is often identified as an important barrier that limits our capacity to predict P loading. In order to address this gap, we constructed spatially explicit datasets of terrestrial P inputs and outputs (fertilizer, confined manure, crop harvest and sewage) across the continental U.S. for 2012. We then examined how these P sources, along with climate, hydrology, and land use, influenced P exports from 72 watersheds as total P (TP) and dissolved inorganic P (DIP) concentrations and yields, and TP fractional export. TP and DIP concentrations and TP yields were best correlated with runoff, but using simple linear regression, we were not able to explain more than 56% of the variance in any of the water quality variables (TP fractional export vs P manure inputs). The lack of clear and strong relationships between contemporary, high-resolution, anthropogenic, terrestrial P and riverine P export at the national scale highlights the fact that a complex suite of factors mediat

  13. Linking terrestrial P inputs to riverine export across the United ...

    EPA Pesticide Factsheets

    Human beings have greatly accelerated phosphorus (P) flows from land to aquatic ecosystems, often resulting in eutrophication, harmful algal blooms, and hypoxia. Although a variety of statistical and mechanistic models have been used to explore the relationship between terrestrial nutrient management and losses to waterways, our understanding of how natural and anthropogenic landscape characteristics mediate losses of P from watersheds lags behind that of nitrogen. The need for higher resolution data is often identified as an important barrier that limits our capacity to predict P loading. In order to address this gap, we constructed spatially explicit datasets of terrestrial P inputs and outputs (fertilizer, confined manure, crop harvest and sewage) across the continental U.S. for 2012. We then examined how these P sources, along with climate, hydrology, and land use, influenced P exports from 72 watersheds as total P (TP) and dissolved inorganic P (DIP) concentrations and yields, and TP fractional export. TP and DIP concentrations and TP yields were best correlated with runoff, but using simple linear regression, we were not able to explain more than 56% of the variance in any of the water quality variables (TP fractional export vs P manure inputs). The lack of clear and strong relationships between contemporary, high-resolution, anthropogenic, terrestrial P and riverine P export at the national scale highlights the fact that a complex suite of factors mediat

  14. Variability in geomorphic response to anthropogenic disturbance

    NASA Astrophysics Data System (ADS)

    Verstraeten, Gert; Notebaert, Bastiaan; D'Haen, Koen; Broothaerts, Nils; De Brue, Hanne

    2013-04-01

    Humans have greatly impacted the processes and intensities of erosion, sediment transport and storage since the introduction of agriculture. However, the relation between the intensity of anthropogenic disturbance and the magnitude of change in sediment dynamics is highly non-linear due to the importance of intrinsic controls on sediment propagation. Especially the buffering capacity of slopes and floodplains can be held responsible for this non-linearity, as both sinks store the produced sediment temporarily, obscuring the relation between sediment production and sediment output. Slope-stream connectivity, but also the duration and typology of anthropogenic disturbance controls the existence of thresholds that need to be crossed before significant changes in downstream sediment dynamics are recorded following human impact. Many internal feedback mechanisms, such as those between erosion and soil thickness, further complicate the story. Several concepts have been developed over the last few decades to explain the complex behavior of sediment transfers in the combined hillslope-fluvial system, including the 'sediment cascade' model and the 'fast-in, slow-out' model. However, none of these concepts seems to hold universally when reconstructing historical sediment dynamics for contrasting environments, as is illustrated with case-studies from a range of environments in Belgium, Turkey and the USA. Detailed field-based sediment budgets from these contrasting settings combined with spatial modeling of sediment fluxes covering time periods ranging from 200 to over 5000 years, as well as the use of pollen and sediment provenancing techniques, shows that no overarching concept of sediment source-to-sink following anthropogenic disturbance can be established. Rather, depending on the duration and typology of anthropogenic disturbances, in combination with local environmental conditions, unique patterns of geomorphic process response emerge. As a result, unraveling the human

  15. Predicting Anthropogenic Noise Contributions to US Waters.

    PubMed

    Gedamke, Jason; Ferguson, Megan; Harrison, Jolie; Hatch, Leila; Henderson, Laurel; Porter, Michael B; Southall, Brandon L; Van Parijs, Sofie

    2016-01-01

    To increase understanding of the potential effects of chronic underwater noise in US waters, the National Oceanic and Atmospheric Administration (NOAA) organized two working groups in 2011, collectively called "CetSound," to develop tools to map the density and distribution of cetaceans (CetMap) and predict the contribution of human activities to underwater noise (SoundMap). The SoundMap effort utilized data on density, distribution, acoustic signatures of dominant noise sources, and environmental descriptors to map estimated temporal, spatial, and spectral contributions to background noise. These predicted soundscapes are an initial step toward assessing chronic anthropogenic noise impacts on the ocean's varied acoustic habitats and the animals utilizing them.

  16. Anthropogenic Elevation Change in the Pacific Northwest

    NASA Astrophysics Data System (ADS)

    Prush, V. B.; Lohman, R. B.

    2013-12-01

    Over the past few decades, interferometric synthetic aperture radar (InSAR) has emerged as a valuable tool for studying crustal deformation signals. Its applications to studies of tectonic and non-tectonic sources are varied, including earthquakes and fault-related processes, volcanic deformation, vegetation structure, and anthropogenic signals. In addition to studies of crustal deformation, the sensitivity of interferometric phase to topography makes InSAR a superb tool for the generation of digital elevation models (DEMs). While much of the focus of InSAR research in recent years has been on deformation, changes in the elevation of the ground surface can be of great scientific or societal interest as well. Examples include elevation and volume change due to anthropogenic processes such as landfill and open-pit mining operations, and natural processes such as glacier thinning or terrain alteration resulting from effusive volcanic eruptions. Our study describes two elevation change signals observed in the Pacific Northwest that are of anthropogenic origin. Using the baseline-dependent nature of the topographic component of interferometric phase, we have determined a proxy for canopy height using coherent interferometric phase differences between adjacent logged and forested regions, as well as a means for determining estimates of the amount and time history of material displaced during mining operations at the Centralia Coal Mine in Centralia, Washington. Quantifying the amount of surface change due to anthropogenic activities is not only critical for tracking the altering landscape of the Pacific Northwest and reducing the observed error in interferograms attributable to elevation change. Deforestation is one of the most significant contributors to global carbon emissions, and quantifying changes in vegetation structure can assist in efforts to monitor and mitigate the effects of deforestation on climate change. Similarly, mining operations can have a lasting

  17. Anthropogenic global warming threatens world cultural heritage

    NASA Astrophysics Data System (ADS)

    Cazenave, Anny

    2014-05-01

    Numerous cultural sites of the United Nations Educational, Scientific and Cultural Organization (UNESCO) world cultural Heritage are located in low-lying coastal regions. Because of anthropogenic global warming and induced sea level rise, many of these sites will be partially or totally flooded in the coming centuries/millennia. This is shown in a recent study by Marzeion and Levermann (2014 Environ. Res. Lett. 9 034001). Projecting future sea level rise and associated regional variability, these authors investigate which sites will be at risk. Because UNESCO cultural sites represent the common heritage of human beings and reflect the Earth and humanity history, they need to be protected for future generations.

  18. Effects of Anthropogenic Nitrogen Loading on Riverine Nitrogen Export in the Northeastern USA

    NASA Astrophysics Data System (ADS)

    Boyer, E. W.; Goodale, C. L.; Howarth, R. W.

    2001-05-01

    Human activities have greatly altered the nitrogen (N) cycle, accelerating the rate of N fixation in landscapes and delivery of N to water bodies. To examine the effects of anthropogenic N inputs on riverine N export, we quantified N inputs and riverine N loss for 16 catchments along a latitudinal profile from Maine to Virginia, which encompass a range of climatic variability and are major drainages to the coast of the North Atlantic Ocean. We quantified inputs of N to each catchment: atmospheric deposition, fertilizer application, agricultural and forest biological N fixation, and the net import of N in food and feed. We compared these inputs with N losses from the system in riverine export. The importance of the relative sources varies widely by watershed and is related to land use. Atmospheric deposition was the largest source (>60%) to the forested catchments of northern New England (e.g., Penobscot and Kennebec); import of N in food was the largest source of N to the more populated regions of southern New England (e.g., Charles and Blackstone); and agricultural inputs were the dominant N sources in the Mid-Atlantic region (e.g., Schuylkill and Potomac). Total N inputs to each catchment increased with percent cover in agriculture and urban land, and decreased with percent forest. Over the combined area of the catchments, net atmospheric deposition was the largest single source input (34%), followed by imports of N in food and feed (24%), fixation in agricultural lands (21%), fertilizer use (15%), and fixation in forests (6%). Riverine export of N is well correlated with N inputs, but it accounts for only a fraction (28%) of the total N inputs. This work provides an understanding of the sources of N in landscapes, and highlights how human activities impact N cycling in the northeast region.

  19. Widespread Anthropogenic Nitrogen in Northwestern Pacific Ocean Sediment.

    PubMed

    Kim, Haryun; Lee, Kitack; Lim, Dhong-Il; Nam, Seung-Il; Kim, Tae-Wook; Yang, Jin-Yu T; Ko, Young Ho; Shin, Kyung-Hoon; Lee, Eunil

    2017-06-06

    Sediment samples from the East China and Yellow seas collected adjacent to continental China were found to have lower δ(15)N values (expressed as δ(15)N = [(15)N:(14)Nsample/(15)N:(14)Nair - 1] × 1000‰; the sediment (15)N:(14)N ratio relative to the air nitrogen (15)N:(14)N ratio). In contrast, the Arctic sediments from the Chukchi Sea, the sampling region furthest from China, showed higher δ(15)N values (2-3‰ higher than those representing the East China and the Yellow sea sediments). Across the sites sampled, the levels of sediment δ(15)N increased with increasing distance from China, which is broadly consistent with the decreasing influence of anthropogenic nitrogen (N(ANTH)) resulting from fossil fuel combustion and fertilizer use. We concluded that, of several processes, the input of N(ANTH) appears to be emerging as a new driver of change in the sediment δ(15)N value in marginal seas adjacent to China. The present results indicate that the effect of N(ANTH) has extended beyond the ocean water column into the deep sedimentary environment, presumably via biological assimilation of N(ANTH) followed by deposition. Further, the findings indicate that N(ANTH) is taking over from the conventional paradigm of nitrate flux from nitrate-rich deep water as the primary driver of biological export production in this region of the Pacific Ocean.

  20. MULTI-SCALE REMOTE SENSING MAPPING OF ANTHROPOGENIC IMPERVIOUS SURFACES: SPATIAL AND TEMPORAL SCALING ISSUES RELATED TO ECOLOGICAL AND HYDROLOGICAL LANDSCAPE ANALYSES

    EPA Science Inventory

    Anthropogenic impervious surfaces are leading contributors to non-point-source water pollution in urban watersheds. These human-created surfaces include such features as roads, parking lots, rooftops, sideways, and driveways. Aerial photography provides a historical vehicle for...

  1. MULTI-SCALE REMOTE SENSING MAPPING OF ANTHROPOGENIC IMPERVIOUS SURFACES: SPATIAL AND TEMPORAL SCALING ISSUES RELATED TO ECOLOGICAL AND HYDROLOGICAL LANDSCAPE ANALYSES

    EPA Science Inventory

    Anthropogenic impervious surfaces are leading contributors to non-point-source water pollution in urban watersheds. These human-created surfaces include such features as roads, parking lots, rooftops, sideways, and driveways. Aerial photography provides a historical vehicle for...

  2. Energy input to the lower thermosphere

    NASA Technical Reports Server (NTRS)

    Johnson, F. S.

    1974-01-01

    The asymmetry in solar heat input to the upper atmosphere at the solstice, and the asymmetry in atomic oxygen production, are largely compensated by a large scale wind system towards the winter polar region. At magnetically disturbed times, atmospheric composition at high winter latitudes changes in such a way as to indicate that polar region heating by magnetic variations, energetic particle inputs, and current systems is more intense than solar heating at low latitudes, thus leading to a reversal of the normal pattern of upper atmospheric circulation. Uncertainties in the intensity of solar radiation responsible for upper atmospheric heating and oxygen dissociation, and uncertainties in the degree of oxygen dissociation in the upper atmosphere, are such that the average rates of eddy mixing may be significantly lower than frequently assumed for the lower thermosphere.

  3. System monitors discrete computer inputs

    NASA Technical Reports Server (NTRS)

    Burns, J. J.

    1966-01-01

    Computer system monitors inputs from checkout devices. The comparing, addressing, and controlling functions are performed in the I/O unit. This leaves the computer main frame free to handle memory, access priority, and interrupt instructions.

  4. Anthropogenic perturbations in marine microbial communities.

    PubMed

    Nogales, Balbina; Lanfranconi, Mariana P; Piña-Villalonga, Juana M; Bosch, Rafael

    2011-03-01

    Human activities impact marine ecosystems at a global scale and all levels of complexity of life. Despite their importance as key players in ecosystem processes, the stress caused to microorganisms has been greatly neglected. This fact is aggravated by difficulties in the analysis of microbial communities and their high diversity, making the definition of patterns difficult. In this review, we discuss the effects of nutrient increase, pollution by organic chemicals and heavy metals and the introduction of antibiotics and pathogens into the environment. Microbial communities respond positively to nutrients and chemical pollution by increasing cell numbers. There are also significant changes in community composition, increases in diversity and high temporal variability. These changes, which evidence the modification of the environmental conditions due to anthropogenic stress, usually alter community functionality, although this aspect has not been explored in depth. Altered microbial communities in human-impacted marine environments can in turn have detrimental effects on human health (i.e. spread of pathogens and antibiotic resistance). New threats to marine ecosystems, i.e. related to climate change, could also have an impact on microbial communities. Therefore, an effort dedicated to analyse the microbial compartment in detail should be made when studying the impact of anthropogenic activities on marine ecosystems.

  5. Observations of anthropogenic cloud condensation nuclei

    NASA Technical Reports Server (NTRS)

    Hudson, James G.

    1990-01-01

    Cloud Condensation Nuclei (CCN) concentrations and spectral measurements obtained with the DRI instantaneous CCN spectrometer (Hudson, 1989) over the last few years are presented. The climatic importance of cloud microphysics has been pointed out. The particles which affect cloud microphysics are cloud condensation nuclei (CCN). The commonly-observed order of magnitude difference in cloud droplet concentrations between maritime and continental air masses (i.e., Squires, 1958) was determined to be caused by systematic differences in the concentrations of CCN between continental and maritime air masses (e.g., Twomey and Wojciechowski, 1969). Twomey (1977) first pointed out that cloud microphysics also affects the radiative properties of clouds. Thus continental and anthropogenic CCN could affect global temperature. Resolution of this Twomey effect requires answers to two questions - whether antropogenic CCN are a significant contribution to atmospheric CCN, and whether they are actually affecting cloud microphysics to an extent which is of climatic importance. The reasons for the contrast between continental and maritime CCN concentration are not understood. The question of the relative importance of anthropogenic CCN is addressed. These observations should shed light on this complex question although further research is being conducted in order to produce more quantitative answers. Accompanying CN measurements made with a TSI 3020 condensation nucleus (CN) counter are also presented.

  6. Iron isotopes in the Seine River (France): Natural versus anthropogenic sources

    NASA Astrophysics Data System (ADS)

    Chen, Jiu-Bin; Busigny, Vincent; Gaillardet, Jérôme; Louvat, Pascale; Wang, Yi-Na

    2014-03-01

    The determination of fluxes and isotope compositions of Fe transported from continents to the ocean is essential for understanding global surface Fe cycle and its effect on oceanic biological productivity. Contrasting to non-polluted rivers, Fe isotope composition in rivers strongly affected by human activities is poorly constrained. In this contribution, we present the first Fe isotope data in suspended particulate matter (SPM) and dissolved load of the human-impacted Seine River (France). Iron concentrations and isotope compositions, together with major and trace element concentrations, were measured for two sample sets: (1) a geographic transect along the river from headwater to estuary, and (2) a temporal series of samples collected in Paris from 2004 to 2007. In the Seine River, Fe is mostly carried by SPM (average 99% of the total Fe) rather than dissolved load. The high Fe enrichment factor (1.40, relative to natural fluvial pre-historical and headwater sediments) and strong correlation between SPM Fe and Zn concentrations (r2 = 0.70, n = 30) demonstrate a strong anthropogenic Fe input. The Fe isotope compositions in SPM show a very small range (δ56Fe from -0.05‰ to 0.09‰) in spite of the large variations of Fe concentrations (from 1.78 to 4.17 wt.%) and are comparable to anthropogenic samples, suggesting that anthropogenic sources have similar Fe isotope composition to that of the natural background. In contrast, larger variations of Fe isotope compositions observed in the dissolved load (from -0.60‰ to 0.06‰) than that of SPM may provide a more promising means for tracing anthropogenic contributions to natural river systems. The δ56Fe and δ66Zn values of the dissolved loads are positively correlated (r2 = 0.62, n = 8), indicating a mixing between anthropogenic and natural end-members, enriched in light and heavy Fe isotopes respectively. Correlation between dissolved δ56Fe and DOC/Fe ratio (i.e. dissolved organic carbon/dissolved Fe

  7. Atmospheric mercury deposition during the last 270 years--A glacial ice core record of natural and anthropogenic sources

    USGS Publications Warehouse

    Schuster, Paul F.; Krabbenhoft, David P.; Naftz, David L.; Cecil, L. DeWayne; Olson, Mark L.; DeWild, John F.; Susong, David D.; Green, Jaromy R.; Abbott, Michael L.

    2002-01-01

    Mercury (Hg) contamination of aquatic ecosystems and subsequent methylmercury bioaccumulation are significant environmental problems of global extent. At regional to global scales, the primary mechanism of Hg contamination is atmospheric Hg transport. Thus, a better understanding of the long-term history of atmospheric Hg cycling and quantification of the sources is critical for assessing the regional and global impact of anthropogenic Hg emissions. Ice cores collected from the Upper Fremont Glacier (UFG), Wyoming, contain a high-resolution record of total atmospheric Hg deposition (ca. 1720−1993). Total Hg in 97 ice-core samples was determined with trace-metal clean handling methods and low-level analytical procedures to reconstruct the first and most comprehensive atmospheric Hg deposition record of its kind yet available from North America. The record indicates major atmospheric releases of both natural and anthropogenic Hg from regional and global sources. Integrated over the past 270-year ice-core history, anthropogenic inputs contributed 52%, volcanic events 6%, and background sources 42%. More significantly, during the last 100 years, anthropogenic sources contributed 70% of the total Hg input. Unlike the 2−7-fold increase observed from preindustrial times (before 1840) to the mid-1980s in sediment-core records, the UFG record indicates a 20-fold increase for the same period. The sediment-core records, however, are in agreement with the last 10 years of this ice-core record, indicating declines in atmospheric Hg deposition.

  8. Rare earth elements in the aragonitic shell of freshwater mussel Corbicula fluminea and the bioavailability of anthropogenic lanthanum, samarium and gadolinium in river water.

    PubMed

    Merschel, Gila; Bau, Michael

    2015-11-15

    High-technology metals - such as the rare earth elements (REE) - have become emerging contaminants in the hydrosphere, yet little is known about their bioavailability. The Rhine River and the Weser River in Germany are two prime examples of rivers that are subjected to anthropogenic REE input. While both rivers carry significant loads of anthropogenic Gd, originating from contrast agents used for magnetic resonance imaging, the Rhine River also carries large amounts of anthropogenic La and lately Sm which are discharged into the river from an industrial point source. Here, we assess the bioavailability of these anthropogenic microcontaminants in these rivers by analyzing the aragonitic shells of the freshwater bivalve Corbicula fluminea. Concentrations of purely geogenic REE in shells of comparable size cover a wide range of about one order of magnitude between different sampling sites. At a given sampling site, geogenic REE concentrations depend on shell size, i.e. mussel age. Although both rivers show large positive Gd anomalies in their dissolved loads, no anomalous enrichment of Gd relative to the geogenic REE can be observed in any of the analyzed shells. This indicates that the speciations of geogenic and anthropogenic Gd in the river water differ from each other and that the geogenic, but not the anthropogenic Gd is incorporated into the shells. In contrast, all shells sampled at sites downstream of the industrial point source of anthropogenic La and Sm in the Rhine River show positive La and Sm anomalies, revealing that these anthropogenic REE are bioavailable. Only little is known about the effects of long-term exposure to dissolved REE and their general ecotoxicity, but considering that anthropogenic Gd and even La have already been identified in German tap water and that anthropogenic La and Sm are bioavailable, this should be monitored and investigated further. Copyright © 2015 Elsevier B.V. All rights reserved.

  9. Lead Test

    MedlinePlus

    ... the condition. Children should also be assessed for iron deficiency and general nutrition consistent with AAP guidelines. BLLs ... raised blood lead concentrations should be tested for iron deficiency . Each person eliminates lead differently. Thus, laboratory tests ...

  10. Lead Poisoning

    MedlinePlus

    ... through deteriorating paint, household dust, bare soil, air, drinking water, food, ceramics, home remedies, hair dyes and other ... an elevated blood lead level can easily result. Drinking water can also sometimes contribute to elevated blood lead ...

  11. Contribution of anthropogenic and natural sources to atmospheric methane variability.

    PubMed

    Bousquet, P; Ciais, P; Miller, J B; Dlugokencky, E J; Hauglustaine, D A; Prigent, C; Van der Werf, G R; Peylin, P; Brunke, E-G; Carouge, C; Langenfelds, R L; Lathière, J; Papa, F; Ramonet, M; Schmidt, M; Steele, L P; Tyler, S C; White, J

    2006-09-28

    Methane is an important greenhouse gas, and its atmospheric concentration has nearly tripled since pre-industrial times. The growth rate of atmospheric methane is determined by the balance between surface emissions and photochemical destruction by the hydroxyl radical, the major atmospheric oxidant. Remarkably, this growth rate has decreased markedly since the early 1990s, and the level of methane has remained relatively constant since 1999, leading to a downward revision of its projected influence on global temperatures. Large fluctuations in the growth rate of atmospheric methane are also observed from one year to the next, but their causes remain uncertain. Here we quantify the processes that controlled variations in methane emissions between 1984 and 2003 using an inversion model of atmospheric transport and chemistry. Our results indicate that wetland emissions dominated the inter-annual variability of methane sources, whereas fire emissions played a smaller role, except during the 1997-1998 El Niño event. These top-down estimates of changes in wetland and fire emissions are in good agreement with independent estimates based on remote sensing information and biogeochemical models. On longer timescales, our results show that the decrease in atmospheric methane growth during the 1990s was caused by a decline in anthropogenic emissions. Since 1999, however, they indicate that anthropogenic emissions of methane have risen again. The effect of this increase on the growth rate of atmospheric methane has been masked by a coincident decrease in wetland emissions, but atmospheric methane levels may increase in the near future if wetland emissions return to their mean 1990s levels.

  12. CLANIMAE: Climatic and Anthropogenic Impacts on African Ecosystems

    NASA Astrophysics Data System (ADS)

    Verschuren, D.; André, L.; Mahy, G.; Cocquyt, C.; Plisnier, P.-D.; Gelorini, V.; Rumes, B.; Lebrun, J.; Bock, L.; Marchant, R.

    2009-04-01

    distribution against lake trophic status and turbidity in the modern-day regional lake gradient. The integrated paleoecological research method of this project addresses the question of past climate-environment-human relationships at the time scale at which the relevant processes have actually occurred. This will allow us to 1) separate the influences of natural climate variability and human activity on East African ecosystems, 2) determine the exact timing and relative magnitude of indigenous (pre-20th century) anthropogenic land clearance compared to recent landscape alteration, 3) determine the severity of lake water-quality losses due to siltation and excess nutrient input directly linked to deforestation and agriculture, compared to those associated with natural ecosystem variability, and 4) assess the resilience of African ecosystems, and prospects for the restoration of disturbed ecosystems if human pressure were to be reversed.

  13. First Global Estimates of Anthropogenic Shortwave Forcing by Methane

    NASA Astrophysics Data System (ADS)

    Collins, William; Feldman, Daniel; Kuo, Chaincy

    2017-04-01

    Although the primary well-mixed greenhouse gases (WMGHGs) absorb both shortwave and longwave radiation, to date assessments of the effects from human-induced increases in atmospheric concentrations of WMGHGs have focused almost exclusively on quantifying the longwave radiative forcing of these gases. However, earlier studies have shown that the shortwave effects of WMGHGs are comparable to many less important longwave forcing agents routinely in these assessments, for example the effects of aircraft contrails, stratospheric anthropogenic methane, and stratospheric water vapor from the oxidation of this methane. These earlier studies include the Radiative Transfer Model Intercomparison Project (RTMIP; Collins et al. 2006) conducted using line-by-line radiative transfer codes as well as the radiative parameterizations from most of the global climate models (GCMs) assembled for the Coupled Model Intercomparison Project (CMIP-3). In this talk, we discuss the first global estimates of the shortwave radiative forcing by methane due to the anthropogenic increase in CH4 between pre-industrial and present-day conditions. This forcing is a balance between reduced heating due to absorption of downwelling sunlight in the stratosphere and increased heating due to absorption of upwelling sunlight reflected from the surface as well clouds and aerosols in the troposphere. These estimates are produced using the Observing System Simulation Experiment (OSSE) framework we have developed for NASA's upcoming Climate Absolute Radiance and Refractivity Observatory (CLARREO) mission. The OSSE is designed to compute the monthly mean shortwave radiative forcing based upon global gridded atmospheric and surface conditions extracted from either the meteorological reanalyses collected for the Analysis for MIPs (Ana4MIPs) or the CMIP-5 multi-GCM archive analyzed in the Fifth Assessment Report (AR-5) of the Intergovernmental Panel on Climate Change (IPCC). The OSSE combines these atmospheric

  14. A record of hydrocarbon input to San Francisco Bay as traced by biomarker profiles in surface sediment and sediment cores

    USGS Publications Warehouse

    Hostettler, F.D.; Pereira, W.E.; Kvenvolden, K.A.; VanGeen, A.; Luoma, S.N.; Fuller, C.C.; Anima, R.

    1999-01-01

    San Francisco Bay is one of the world's largest urbanized estuarine systems. Its water and sediment receive organic input from a wide variety of sources; much of this organic material is anthropogenically derived. To document the spatial and historical record of the organic contaminant input, surficial sediment from 17 sites throughout San Francisco Bay and sediment cores from two locations Richardson Bay and San Pablo Bay were analyzed for biomarker constituents. Biomarkers, that is, 'molecular fossils', primarily hopanes, steranes, and n-alkanes, provide information on anthropogenic contamination, especially that related to petrogenic sources, as well as on recent input of biogenic material. The biomarker parameters from the surficial sediment and the upper horizons of the cores show a dominance of anthropogenic input, whereas the biomarker profiles at the lower horizons of the cores indicate primarily biogenic input. In the Richardson Bay core the gradual upcore transition from lower maturity background organics to a dominance of anthropogenic contamination occurred about 70-100 years ago and corresponds to the industrial development of the San Francisco Bay area. In San Pablo Bay, the transition was very abrupt, reflecting the complex depositional history of the area. This sharp transition, perhaps indicating a depositional hiatus or erosional period, dated at pre-1952, is clearly visible. Below, the hiatus the biomarker parameters are immature; above, they are mature and show an anthropogenic overlay. Higher concentrations of terrigenous n-alkanes in the upper horizons in this core are indicative of an increase in terrigenous organic matter input in San Pablo Bay, possibly a result of water diversion projects and changes in the fresh water flow into the Bay from the Delta. Alternatively, it could reflect a dilution of organic material in the lower core sections with hydraulic mining debris.

  15. Anthropogenic disturbances are key to maintaining the biodiversity of grasslands.

    PubMed

    Yuan, Z Y; Jiao, F; Li, Y H; Kallenbach, Robert L

    2016-02-23

    Although anthropogenic disturbances are often perceived as detrimental to plant biodiversity, the relationship between biodiversity and disturbance remains unclear. Opinions diverge on how natural diversity is generated and maintained. We conducted a large-scale investigation of a temperate grassland system in Inner Mongolia and assessed the richness-disturbance relationship using grazing intensity, the primary anthropogenic disturbance in the region. Vascular plant-species richness peaked at an intermediate level of anthropogenic disturbance. Our results support the Intermediate Disturbance Hypothesis, which provides a valid and useful measure of biodiversity at a metacommunity scale, indicating that anthropogenic disturbances are necessary to conserve the biodiversity of grassland systems.

  16. Anthropogenic disturbances are key to maintaining the biodiversity of grasslands

    PubMed Central

    Yuan, Z. Y.; Jiao, F.; Li, Y. H.; Kallenbach, Robert L.

    2016-01-01

    Although anthropogenic disturbances are often perceived as detrimental to plant biodiversity, the relationship between biodiversity and disturbance remains unclear. Opinions diverge on how natural diversity is generated and maintained. We conducted a large-scale investigation of a temperate grassland system in Inner Mongolia and assessed the richness-disturbance relationship using grazing intensity, the primary anthropogenic disturbance in the region. Vascular plant-species richness peaked at an intermediate level of anthropogenic disturbance. Our results support the Intermediate Disturbance Hypothesis, which provides a valid and useful measure of biodiversity at a metacommunity scale, indicating that anthropogenic disturbances are necessary to conserve the biodiversity of grassland systems. PMID:26903041

  17. Anthropogenic disturbances are key to maintaining the biodiversity of grasslands

    NASA Astrophysics Data System (ADS)

    Yuan, Z. Y.; Jiao, F.; Li, Y. H.; Kallenbach, Robert L.

    2016-02-01

    Although anthropogenic disturbances are often perceived as detrimental to plant biodiversity, the relationship between biodiversity and disturbance remains unclear. Opinions diverge on how natural diversity is generated and maintained. We conducted a large-scale investigation of a temperate grassland system in Inner Mongolia and assessed the richness-disturbance relationship using grazing intensity, the primary anthropogenic disturbance in the region. Vascular plant-species richness peaked at an intermediate level of anthropogenic disturbance. Our results support the Intermediate Disturbance Hypothesis, which provides a valid and useful measure of biodiversity at a metacommunity scale, indicating that anthropogenic disturbances are necessary to conserve the biodiversity of grassland systems.

  18. Giant natural fluctuation models and anthropogenic warming

    NASA Astrophysics Data System (ADS)

    Lovejoy, S.; Rio Amador, L.; Hébert, R.; Lima, I.

    2016-08-01

    Explanations for the industrial epoch warming are polarized around the hypotheses of anthropogenic warming (AW) and giant natural fluctuations (GNFs). While climate sceptics have systematically attacked AW, up until now they have only invoked GNFs. This has now changed with the publication by D. Keenan of a sample of 1000 series from stochastic processes purporting to emulate the global annual temperature since 1880. While Keenan's objective was to criticize the International Panel on Climate Change's trend uncertainty analysis (their assumption that residuals are only weakly correlated), for the first time it is possible to compare a stochastic GNF model with real data. Using Haar fluctuations, probability distributions, and other techniques of time series analysis, we show that his model has unrealistically strong low-frequency variability so that even mild extrapolations imply ice ages every ≈1000 years. Helped by statistics, the GNF model can easily be scientifically rejected.

  19. Anthropogenic noise increases fish mortality by predation

    PubMed Central

    Simpson, Stephen D.; Radford, Andrew N.; Nedelec, Sophie L.; Ferrari, Maud C. O.; Chivers, Douglas P.; McCormick, Mark I.; Meekan, Mark G.

    2016-01-01

    Noise-generating human activities affect hearing, communication and movement in terrestrial and aquatic animals, but direct evidence for impacts on survival is rare. We examined effects of motorboat noise on post-settlement survival and physiology of a prey fish species and its performance when exposed to predators. Both playback of motorboat noise and direct disturbance by motorboats elevated metabolic rate in Ambon damselfish (Pomacentrus amboinensis), which when stressed by motorboat noise responded less often and less rapidly to simulated predatory strikes. Prey were captured more readily by their natural predator (dusky dottyback, Pseudochromis fuscus) during exposure to motorboat noise compared with ambient conditions, and more than twice as many prey were consumed by the predator in field experiments when motorboats were passing. Our study suggests that a common source of noise in the marine environment has the potential to impact fish demography, highlighting the need to include anthropogenic noise in management plans. PMID:26847493

  20. Anthropogenic sulfur dioxide emissions: 1850-2005

    SciTech Connect

    Smith, S. J.; Van Aardenne, J.; Klimont, Z.; Andres, Robert Joseph; Volke, A.; Delgado Arias, S

    2011-01-01

    Sulfur aerosols impact human health, ecosystems, agriculture, and global and regional climate. A new annual estimate of anthropogenic global and regional sulfur dioxide emissions has been constructed spanning the period 1850 2005 using a bottom-up mass balance method, calibrated to country-level inventory data. Global emissions peaked in the early 1970s and decreased until 2000, with an increase in recent years due to increased emissions in China, international shipping, and developing countries in general. An uncertainty analysis was conducted including both random and systemic uncertainties. The overall global uncertainty in sulfur dioxide emissions is relatively small, but regional uncertainties ranged up to 30%. The largest contributors to uncertainty at present are emissions from China and international shipping. Emissions were distributed on a 0.5 grid by sector for use in coordinated climate model experiments.

  1. Anthropogenic Sulfur Dioxide Emissions: 1850-2005

    SciTech Connect

    Smith, Steven J.; van Aardenne, John; Klimont, Z.; Andres, Robert; Volke, April C.; Delgado Arias, Sabrina

    2011-01-02

    Sulfur aerosols impact human health, ecosystems, agriculture, and global and regional climate. A new annual estimate of anthropogenic global and regional sulfur dioxide emissions has been constructed spanning the period 1850 - 2005. A combination of mass balance and best available inventory data was used in order to achieve the most accurate estimate possible. Global emissions peaked in the early 1970s and decreased until 2000, with an increase in recent years due to increased emissions in China, international shipping, and developing countries in general. An uncertainty analysis was conducted including both random and systemic uncertainties. The overall global uncertainty in sulfur dioxide emissions is relatively small, but regional uncertainties of up to 30% were found. The largest contributors to uncertainty at present are emissions from China and international shipping.

  2. Anthropogenic noise increases fish mortality by predation.

    PubMed

    Simpson, Stephen D; Radford, Andrew N; Nedelec, Sophie L; Ferrari, Maud C O; Chivers, Douglas P; McCormick, Mark I; Meekan, Mark G

    2016-02-05

    Noise-generating human activities affect hearing, communication and movement in terrestrial and aquatic animals, but direct evidence for impacts on survival is rare. We examined effects of motorboat noise on post-settlement survival and physiology of a prey fish species and its performance when exposed to predators. Both playback of motorboat noise and direct disturbance by motorboats elevated metabolic rate in Ambon damselfish (Pomacentrus amboinensis), which when stressed by motorboat noise responded less often and less rapidly to simulated predatory strikes. Prey were captured more readily by their natural predator (dusky dottyback, Pseudochromis fuscus) during exposure to motorboat noise compared with ambient conditions, and more than twice as many prey were consumed by the predator in field experiments when motorboats were passing. Our study suggests that a common source of noise in the marine environment has the potential to impact fish demography, highlighting the need to include anthropogenic noise in management plans.

  3. Anthropogenic sulfur dioxide emissions: 1850-2005

    NASA Astrophysics Data System (ADS)

    Smith, S. J.; van Aardenne, J.; Klimont, Z.; Andres, R.; Volke, A.; Delgado Arias, S.

    2010-06-01

    Sulfur aerosols impact human health, ecosystems, agriculture, and global and regional climate. A new annual estimate of anthropogenic global and regional sulfur dioxide emissions has been constructed spanning the period 1850-2005 using a bottom-up mass balance method, calibrated to country-level inventory data. Global emissions peaked in the early 1970s and decreased until 2000, with an increase in recent years due to increased emissions in China, international shipping, and developing countries in general. An uncertainty analysis was conducted including both random and systemic uncertainties. The overall global uncertainty in sulfur dioxide emissions is relatively small, but regional uncertainties ranged up to 30%. The largest contributors to uncertainty at present are emissions from China and international shipping. Emissions were distributed on a 0.5° grid by sector for use in coordinated climate model experiments.

  4. Anthropogenic sulfur dioxide emissions: 1850-2005

    NASA Astrophysics Data System (ADS)

    Smith, S. J.; van Aardenne, J.; Klimont, Z.; Andres, R. J.; Volke, A.; Delgado Arias, S.

    2011-02-01

    Sulfur aerosols impact human health, ecosystems, agriculture, and global and regional climate. A new annual estimate of anthropogenic global and regional sulfur dioxide emissions has been constructed spanning the period 1850-2005 using a bottom-up mass balance method, calibrated to country-level inventory data. Global emissions peaked in the early 1970s and decreased until 2000, with an increase in recent years due to increased emissions in China, international shipping, and developing countries in general. An uncertainty analysis was conducted including both random and systemic uncertainties. The overall global uncertainty in sulfur dioxide emissions is relatively small, but regional uncertainties ranged up to 30%. The largest contributors to uncertainty at present are emissions from China and international shipping. Emissions were distributed on a 0.5° grid by sector for use in coordinated climate model experiments.

  5. Input Type and Parameter Resetting: Is Naturalistic Input Necessary?

    ERIC Educational Resources Information Center

    Rothman, Jason; Iverson, Michael

    2007-01-01

    It has been argued that extended exposure to naturalistic input provides L2 learners with more of an opportunity to converge of target morphosyntactic competence as compared to classroom-only environments, given that the former provide more positive evidence of less salient linguistic properties than the latter (e.g., Isabelli 2004). Implicitly,…

  6. Mass exchange processes with input

    NASA Astrophysics Data System (ADS)

    Krapivsky, P. L.

    2015-05-01

    We investigate a system of interacting clusters evolving through mass exchange and supplemented by input of small clusters. Three possibilities depending on the rate of exchange generically occur when input is homogeneous: continuous growth, gelation, and instantaneous gelation. We mostly study the growth regime using scaling methods. An exchange process with reaction rates equal to the product of reactant masses admits an exact solution which allows us to justify the validity of scaling approaches in this special case. We also investigate exchange processes with a localized input. We show that if the diffusion coefficients are mass-independent, the cluster mass distribution becomes stationary and develops an algebraic tail far away from the source.

  7. Tracking Public Beliefs About Anthropogenic Climate Change

    PubMed Central

    Hamilton, Lawrence C.; Hartter, Joel; Lemcke-Stampone, Mary; Moore, David W.; Safford, Thomas G.

    2015-01-01

    A simple question about climate change, with one choice designed to match consensus statements by scientists, was asked on 35 US nationwide, single-state or regional surveys from 2010 to 2015. Analysis of these data (over 28,000 interviews) yields robust and exceptionally well replicated findings on public beliefs about anthropogenic climate change, including regional variations, change over time, demographic bases, and the interacting effects of respondent education and political views. We find that more than half of the US public accepts the scientific consensus that climate change is happening now, caused mainly by human activities. A sizable, politically opposite minority (about 30 to 40%) concede the fact of climate change, but believe it has mainly natural causes. Few (about 10 to 15%) say they believe climate is not changing, or express no opinion. The overall proportions appear relatively stable nationwide, but exhibit place-to-place variations. Detailed analysis of 21 consecutive surveys within one fairly representative state (New Hampshire) finds a mild but statistically significant rise in agreement with the scientific consensus over 2010–2015. Effects from daily temperature are detectable but minor. Hurricane Sandy, which brushed New Hampshire but caused no disaster there, shows no lasting impact on that state’s time series—suggesting that non-immediate weather disasters have limited effects. In all datasets political orientation dominates among individual-level predictors of climate beliefs, moderating the otherwise positive effects from education. Acceptance of anthropogenic climate change rises with education among Democrats and Independents, but not so among Republicans. The continuing series of surveys provides a baseline for tracking how future scientific, political, socioeconomic or climate developments impact public acceptance of the scientific consensus. PMID:26422694

  8. Anthropogenic Carbon Pump in an Urbanized Estuary

    NASA Astrophysics Data System (ADS)

    Park, J. H.; Yoon, T. K.; Jin, H.; Begum, M. S.

    2015-12-01

    The importance of estuaries as a carbon source has been increasingly recognized over the recent decades. However, constraining sources of CO2 evasion from urbanized estuaries remains incomplete, particularly in densely populated river systems receiving high loads of organic carbon from anthropogenic sources. To account for major factors regulating carbon fluxes the tidal reach of the Han River estuary along the metropolitan Seoul, characterization of organic carbon in the main stem and major urban tributaries were combined with continuous, submersible sensor measurements of pCO2 at a mid-channel location over a year and continuous underway measurements using a submersible sensor and two equilibrator sytems across the estuarine section receiving urban streams. Single-site continuous measurements exhibited large seasonal and diurnal variations in pCO2, ranging from sub-ambient air levels to exceptionally high values approaching 10,000 ppm. Diurnal variations of pCO2 were pronounced in summer and had an inverse relationship with dissolved oxygen, pointing to a potential role of day-time algal consumption of CO2. Cruise measurements displayed sharp pCO2 pulses along the confluences of urban streams as compared with relatively low values along the upper estuary receiving low-CO2 outflows from upstream dams. Large downstream increases in pCO2, concurrent with increases in DOC concentrations and fluorescence intensities indicative of microbially processed organic components, imply a translocation and subsequent dilution of CO2 carried by urban streams and/or fast transformations of labile C during transit along downstream reaches. The unique combination of spatial and temporal continuous measurements of pCO2 provide insights on estuarine CO2 pulses that might have resulted from the interplay between high loads of CO2 and organic C of anthropogenic origin and their priming effects on estuarine microbial processing of terrigenous and algal organic matter.

  9. Car Catalysts Impact on Anthropogenic Osmium Budget

    NASA Astrophysics Data System (ADS)

    Poirier, A.; Gariepy, C.

    2004-05-01

    A few sources of anthropogenic osmium have been identified that clearly contribute to the observed increase in unradiogenic osmium in recent urban sediments (a major one being biomedical use of OsO4 as a lipid stain used to enhance cell structures for optical and electron microscopy (1,2,3,4)). Previous studies suggested the possibility that automobile catalytic converters might also contribute to this Os pollution, even though this metal is not directly employed in car catalysts (1,4). The importance of this potential source has never been quantitatively tested. Here, we present results for the Os isotope analysis of 4 new catalytic converters. The unradiogenic 187Os/188Os composition of all catalytic converters is similar to typical platinum group elements ore (5). The measured Os concentrations are in the pg/g range (6-228 pg/g). The physical conditions in catalysts (oxidising environment and 300 \\deg C) are effective in promoting the oxidation of osmium to its gaseous form. We therefore expect that osmium volatility plays an important role in releasing Os from the catalysts. Based on measured concentrations, we estimate that car catalysts could be responsible for up to several picograms of anthropogenic osmium deposited per square meter in urban areas every year. Our results strengthen the idea that automobile catalytic converters might be a significant source of Os pollution. 1.Ravizza, G. E. and Bothner, M. H. (1996) Geochimica et Cosmochimica Acta, 60; 15, 2753-2763. 2.Smith, I. C., Carson, B. L., and Ferguson T.L. (1974) Environmental Health Perspectives, 8, 201-213. 3.Esser, B. K. and Turekian, K. K. (1993) Environmental Science and Technology, 27; 13, 2719-2724. 4.Rauch S., Hemond H.F., and Peucker-Ehrenbrink, B. (2004) Environmental Science and Technology, 38, 396-402. 5.McCandless, T. and Ruiz, J. (1991) Geology, 19, 1225-1228.

  10. Tracking Public Beliefs About Anthropogenic Climate Change.

    PubMed

    Hamilton, Lawrence C; Hartter, Joel; Lemcke-Stampone, Mary; Moore, David W; Safford, Thomas G

    2015-01-01

    A simple question about climate change, with one choice designed to match consensus statements by scientists, was asked on 35 US nationwide, single-state or regional surveys from 2010 to 2015. Analysis of these data (over 28,000 interviews) yields robust and exceptionally well replicated findings on public beliefs about anthropogenic climate change, including regional variations, change over time, demographic bases, and the interacting effects of respondent education and political views. We find that more than half of the US public accepts the scientific consensus that climate change is happening now, caused mainly by human activities. A sizable, politically opposite minority (about 30 to 40%) concede the fact of climate change, but believe it has mainly natural causes. Few (about 10 to 15%) say they believe climate is not changing, or express no opinion. The overall proportions appear relatively stable nationwide, but exhibit place-to-place variations. Detailed analysis of 21 consecutive surveys within one fairly representative state (New Hampshire) finds a mild but statistically significant rise in agreement with the scientific consensus over 2010-2015. Effects from daily temperature are detectable but minor. Hurricane Sandy, which brushed New Hampshire but caused no disaster there, shows no lasting impact on that state's time series-suggesting that non-immediate weather disasters have limited effects. In all datasets political orientation dominates among individual-level predictors of climate beliefs, moderating the otherwise positive effects from education. Acceptance of anthropogenic climate change rises with education among Democrats and Independents, but not so among Republicans. The continuing series of surveys provides a baseline for tracking how future scientific, political, socioeconomic or climate developments impact public acceptance of the scientific consensus.

  11. Global inventory of volatile organic compound emissions from anthropogenic sources. Final report, March 1988-September 1990

    SciTech Connect

    Watson, J.J.; Probert, J.A.; Piccot, S.D.

    1991-01-01

    The report describes a global inventory of anthropogenic volatile organic compound (VOC) emissions that includes a separate inventory for each of seven pollutant groups--paraffins, olefins, aromatics, formaldehyde, other aldehydes, other aromatics, and marginally reactive compounds. The inventory, one input to atmospheric chemistry models required to estimate the global atmospheric concentration of ozone, is part of an assessment of the potential environmental impacts associated with global climate change. Study results show total global anthropogenic emissions of about 121 million short tons of VOCs per year. The U.S. is the largest emitter with 21% of the total. Globally, fuelwood combustion and savanna burning are the largest sources, together accounting for over 35% of global VOC emissions. The approach used to develop the inventory involved: (1) identifying the major anthropogenic sources of VOC emissions in the U.S. and grouping them into categories; (2) developing emission factors by dividing the U.S. emissions by the amount of production or consumption of the related commodity in the U.S.; (3) multiplying the U.S. emission factors by production/consumption statistics for other countries to yield global VOC emission estimates; and (4) geographically distributing the emissions.

  12. Investigation of air pollution and regional climate change due to anthropogenic aerosols

    NASA Astrophysics Data System (ADS)

    Nakata, Makiko; Sano, Itaru; Mukai, Sonoyo

    2016-10-01

    Increased emissions of anthropogenic aerosols associated with economic growth can lead to increased concentrations of hazardous air pollutants. In particular, large cities in East Asia have experienced numerous heavy haze episodes. Atmospheric aerosol distributions in East Asia are complex, being influenced by both natural phenomena and human activity, with urban areas in particular being dominated by fine anthropogenic aerosols released from diesel-powered vehicles and industrial activity. In Japan, air pollution levels have been reduced; nevertheless, in recent years, there is increasing concern regarding air pollution caused by fine particulate matter. The origins of air pollution were examined, focusing on the comparison between aerosol properties observed from satellites and that on the ground. Because of their short life spans, concentrations of anthropogenic aerosols are highest over the source regions, and as a result, the climatic impacts of anthropogenic aerosols are also found to be most pronounced in these regions. In this study, aerosol impacts on climate are assessed by numerical model simulations. The direct effects of aerosols include reduced solar radiation, and hence a decrease in surface temperatures. In addition to these changes in the radiation budget, aerosols have a significant potential to change cloud and precipitation fields. These climatic responses to aerosols can manifest far from their source regions with high industrial activities.

  13. Lead Pencils

    NASA Technical Reports Server (NTRS)

    Gray, L. B.

    1971-01-01

    A study, undertaken to determine the lead content of paint on various pencils in the Goddard supply system, is reported. The survey found that lead content varied from .04 mg per pencil for carmine colored pencils to approximately 43 mg per pencil for yellow colored pencils. Results also show that yellow pencils had higher lead content than other colors analyzed. More detailed results are given in tabular form.

  14. Anthropogenic influence on forest landscape in the Khumbu valley, Nepal

    NASA Astrophysics Data System (ADS)

    Lingua, Emanuele; Garbarino, Matteo; Urbinati, Carlo; Carrer, Marco

    2013-04-01

    High altitude Himalayan regions are geo-dynamically very active and very sensitive to natural and anthropogenic disturbances due to their steep slopes, variations of precipitations with elevation and short growing periods. Nonetheless, even in this remote region human pressure is often the most important factor affecting forest landscape. In the last decades the firewood demand has increased each year between September to December. The increase in the number of tourists, mountaineering, guides, porters, carpenters, lodges lead to a peak in the use of fuelwood. In order to understand anthropogenic impacts on forest, resources landscape and stand scale dynamics were analyzed in the Sagarmatha National Park (SNP) and its Buffer Zone in the Khumbu Valley (Nepal, Eastern Himalaya). Biological and historical data sources were employed, and a multi-scale approach was adopted to capture the influence of human activities on the distribution of tree species and forest structure. Stand structure and a range of environmental variables were sampled in 197 20x20 m square plots, and land use and anthropogenic variables were derived in a GIS environment (thematic maps and IKONOS, Landsat and Terra ASTER satellite images). We used multivariate statistical analyses to relate forest structure, anthropogenic influences, land uses, and topography. Fuel wood is the prime source of energy for cooking (1480-1880 Kg/person/year) and Quercus semecarpifolia, Rhododendron arboreum and Pinus wallichiana, among the others, are the most exploited species. Due to lack of sufficient energy sources deforestation is becoming a problem in the area. This might be a major threat causing soil erosion, landslides and other natural hazards. Among the 25 species of trees that were found in the Buffer Zone Community Forests of SNP, Pinus wallichiana, Lyonia ovalifolia, Quercus semecarpifolia and Rhododendron arboreum are the dominant species. The total stand density ranged from 228 to 379 tree/ha and the

  15. Shrub encroachment in North American grasslands: Shifts in growth form dominance rapidly alters control of ecosystem carbon inputs

    USDA-ARS?s Scientific Manuscript database

    Shrub encroachment into grass-dominated biomes is occurring globally due to a variety of anthropogenic activities, but the consequences for carbon (C) inputs, storage and cycling remain unclear. We studied eight North American graminoid-dominated ecosystems invaded by shrubs, from arctic tundra to ...

  16. History of nutrient inputs to the northeastern United States, 1930-2000

    NASA Astrophysics Data System (ADS)

    Hale, Rebecca L.; Hoover, Joseph H.; Wollheim, Wilfred M.; VöRöSmarty, Charles J.

    2013-04-01

    Humans have dramatically altered nutrient cycles at local to global scales. We examined changes in anthropogenic nutrient inputs to the northeastern United States (NE) from 1930 to 2000. We created a comprehensive time series of anthropogenic N and P inputs to 437 counties in the NE at 5 year intervals. Inputs included atmospheric N deposition, biological N2 fixation, fertilizer, detergent P, livestock feed, and human food. Exports included exports of feed and food and volatilization of ammonia. N inputs to the NE increased throughout the study period, primarily due to increases in atmospheric deposition and fertilizer. P inputs increased until 1970 and then declined due to decreased fertilizer and detergent inputs. Livestock consistently consumed the majority of nutrient inputs over time and space. The area of crop agriculture declined during the study period but consumed more nutrients as fertilizer. We found that stoichiometry (N:P) of inputs and absolute amounts of N matched nutritional needs (livestock, humans, crops) when atmospheric components (N deposition, N2 fixation) were not included. Differences between N and P led to major changes in N:P stoichiometry over time, consistent with global trends. N:P decreased from 1930 to 1970 due to increased inputs of P, and increased from 1970 to 2000 due to increased N deposition and fertilizer and decreases in P fertilizer and detergent use. We found that nutrient use is a dynamic product of social, economic, political, and environmental interactions. Therefore, future nutrient management must take into account these factors to design successful and effective nutrient reduction measures.

  17. Regional Hospital Input Price Indexes

    PubMed Central

    Freeland, Mark S.; Schendler, Carol Ellen; Anderson, Gerard

    1981-01-01

    This paper describes the development of regional hospital input price indexes that is consistent with the general methodology used for the National Hospital Input Price Index. The feasibility of developing regional indexes was investigated because individuals inquired whether different regions experienced different rates of increase in hospital input prices. The regional indexes incorporate variations in cost-share weights (the amount an expense category contributes to total spending) associated with hospital type and location, and variations in the rate of input price increases for various regions. We found that between 1972 and 1979 none of the regional price indexes increased at average annual rates significantly different from the national rate. For the more recent period 1977 through 1979, the increase in one Census Region was significantly below the national rate. Further analyses indicated that variations in cost-share weights for various types of hospitals produced no substantial variations in the regional price indexes relative to the national index. We consider these findings preliminary because of limitations in the availability of current, relevant, and reliable data, especially for local area wage rate increases. PMID:10309557

  18. Lab Inputs for Common Micros.

    ERIC Educational Resources Information Center

    Tinker, Robert

    1984-01-01

    The game paddle inputs of Apple microcomputers provide a simple way to get laboratory measurements into the computer. Discusses these game paddles and the necessary interface software. Includes schematics for Apple built-in paddle electronics, TRS-80 game paddle I/O, Commodore circuit for user port, and bus interface for Sinclair/Timex, Commodore,…

  19. Analog Input Data Acquisition Software

    NASA Technical Reports Server (NTRS)

    Arens, Ellen

    2009-01-01

    DAQ Master Software allows users to easily set up a system to monitor up to five analog input channels and save the data after acquisition. This program was written in LabVIEW 8.0, and requires the LabVIEW runtime engine 8.0 to run the executable.

  20. The advanced LIGO input optics

    NASA Astrophysics Data System (ADS)

    Mueller, Chris L.; Arain, Muzammil A.; Ciani, Giacomo; DeRosa, Ryan. T.; Effler, Anamaria; Feldbaum, David; Frolov, Valery V.; Fulda, Paul; Gleason, Joseph; Heintze, Matthew; Kawabe, Keita; King, Eleanor J.; Kokeyama, Keiko; Korth, William Z.; Martin, Rodica M.; Mullavey, Adam; Peold, Jan; Quetschke, Volker; Reitze, David H.; Tanner, David B.; Vorvick, Cheryl; Williams, Luke F.; Mueller, Guido

    2016-01-01

    The advanced LIGO gravitational wave detectors are nearing their design sensitivity and should begin taking meaningful astrophysical data in the fall of 2015. These resonant optical interferometers will have unprecedented sensitivity to the strains caused by passing gravitational waves. The input optics play a significant part in allowing these devices to reach such sensitivities. Residing between the pre-stabilized laser and the main interferometer, the input optics subsystem is tasked with preparing the laser beam for interferometry at the sub-attometer level while operating at continuous wave input power levels ranging from 100 mW to 150 W. These extreme operating conditions required every major component to be custom designed. These designs draw heavily on the experience and understanding gained during the operation of Initial LIGO and Enhanced LIGO. In this article, we report on how the components of the input optics were designed to meet their stringent requirements and present measurements showing how well they have lived up to their design.

  1. The advanced LIGO input optics

    SciTech Connect

    Mueller, Chris L. Arain, Muzammil A.; Ciani, Giacomo; Feldbaum, David; Fulda, Paul; Gleason, Joseph; Heintze, Matthew; Martin, Rodica M.; Reitze, David H.; Tanner, David B.; Williams, Luke F.; Mueller, Guido; DeRosa, Ryan T.; Effler, Anamaria; Kokeyama, Keiko; Frolov, Valery V.; Mullavey, Adam; Kawabe, Keita; Vorvick, Cheryl; King, Eleanor J.; and others

    2016-01-15

    The advanced LIGO gravitational wave detectors are nearing their design sensitivity and should begin taking meaningful astrophysical data in the fall of 2015. These resonant optical interferometers will have unprecedented sensitivity to the strains caused by passing gravitational waves. The input optics play a significant part in allowing these devices to reach such sensitivities. Residing between the pre-stabilized laser and the main interferometer, the input optics subsystem is tasked with preparing the laser beam for interferometry at the sub-attometer level while operating at continuous wave input power levels ranging from 100 mW to 150 W. These extreme operating conditions required every major component to be custom designed. These designs draw heavily on the experience and understanding gained during the operation of Initial LIGO and Enhanced LIGO. In this article, we report on how the components of the input optics were designed to meet their stringent requirements and present measurements showing how well they have lived up to their design.

  2. The advanced LIGO input optics.

    PubMed

    Mueller, Chris L; Arain, Muzammil A; Ciani, Giacomo; DeRosa, Ryan T; Effler, Anamaria; Feldbaum, David; Frolov, Valery V; Fulda, Paul; Gleason, Joseph; Heintze, Matthew; Kawabe, Keita; King, Eleanor J; Kokeyama, Keiko; Korth, William Z; Martin, Rodica M; Mullavey, Adam; Peold, Jan; Quetschke, Volker; Reitze, David H; Tanner, David B; Vorvick, Cheryl; Williams, Luke F; Mueller, Guido

    2016-01-01

    The advanced LIGO gravitational wave detectors are nearing their design sensitivity and should begin taking meaningful astrophysical data in the fall of 2015. These resonant optical interferometers will have unprecedented sensitivity to the strains caused by passing gravitational waves. The input optics play a significant part in allowing these devices to reach such sensitivities. Residing between the pre-stabilized laser and the main interferometer, the input optics subsystem is tasked with preparing the laser beam for interferometry at the sub-attometer level while operating at continuous wave input power levels ranging from 100 mW to 150 W. These extreme operating conditions required every major component to be custom designed. These designs draw heavily on the experience and understanding gained during the operation of Initial LIGO and Enhanced LIGO. In this article, we report on how the components of the input optics were designed to meet their stringent requirements and present measurements showing how well they have lived up to their design.

  3. Signal Prediction With Input Identification

    NASA Technical Reports Server (NTRS)

    Juang, Jer-Nan; Chen, Ya-Chin

    1999-01-01

    A novel coding technique is presented for signal prediction with applications including speech coding, system identification, and estimation of input excitation. The approach is based on the blind equalization method for speech signal processing in conjunction with the geometric subspace projection theory to formulate the basic prediction equation. The speech-coding problem is often divided into two parts, a linear prediction model and excitation input. The parameter coefficients of the linear predictor and the input excitation are solved simultaneously and recursively by a conventional recursive least-squares algorithm. The excitation input is computed by coding all possible outcomes into a binary codebook. The coefficients of the linear predictor and excitation, and the index of the codebook can then be used to represent the signal. In addition, a variable-frame concept is proposed to block the same excitation signal in sequence in order to reduce the storage size and increase the transmission rate. The results of this work can be easily extended to the problem of disturbance identification. The basic principles are outlined in this report and differences from other existing methods are discussed. Simulations are included to demonstrate the proposed method.

  4. Optimal Inputs for System Identification.

    DTIC Science & Technology

    1995-09-01

    The derivation of the power spectral density of the optimal input for system identification is addressed in this research. Optimality is defined in...identification potential of general System Identification algorithms, a new and efficient System Identification algorithm that employs Iterated Weighted Least

  5. Lab Inputs for Common Micros.

    ERIC Educational Resources Information Center

    Tinker, Robert

    1984-01-01

    The game paddle inputs of Apple microcomputers provide a simple way to get laboratory measurements into the computer. Discusses these game paddles and the necessary interface software. Includes schematics for Apple built-in paddle electronics, TRS-80 game paddle I/O, Commodore circuit for user port, and bus interface for Sinclair/Timex, Commodore,…

  6. Leading Democratically

    ERIC Educational Resources Information Center

    Brookfield, Stephen

    2010-01-01

    Democracy is the most venerated of American ideas, the one for which wars are fought and people die. So most people would probably agree that leaders should be able to lead well in a democratic society. Yet, genuinely democratic leadership is a relative rarity. Leading democratically means viewing leadership as a function or process, rather than…

  7. Historical perspective of industrial lead emissions to the atmosphere from a Canadian smelter.

    PubMed

    Gallon, Céline; Tessier, André; Gobeil, Charles; Carignan, Richard

    2006-02-01

    Dated sediment cores from four remote Canadian Shield headwater lakes, where atmospheric deposition has been the only input of anthropogenic Pb, situated along a transect extending 300 km from a nonferrous metal smelter, were analyzed for both lead concentrations and isotopic composition; porewater samples collected at the same sites were analyzed for Pb and other geochemical variables. The depth distributions of stable Pb isotope ratios show the presence of several isotopically distinct Pb types since the preindustrial period. Lead from the smelter emissions had an isotopic signature (e.g., 206Pb/207Pb approximately 0.993) that was clearly distinct from those of Pb in aerosols collected at sites remotefrom point sources in Eastern Canada (e.g., 206Pb/207Pb usually approximately 1.15-1.20) and the United States (e.g., 206Pb/207Pb usually approximately 1.15-1.22), allowing the geographical area impacted by the smelter Pb emissions to be traced. On the basis of the sediment Pb isotopic composition, it is estimated that lead from the smelter accounts for 89%, 88%, and 5-34% of the total inventory of anthropogenic Pb deposited in the sediments of lakes located 10, 25, and 150 km from the smelter, respectively; but lead from this point source was not detected in sediments of a fourth lake that is 300 km from the smelter. We also estimate that the amount of smelter-derived Pb deposited within a distance of 150 km is equivalent to 5-10% of the amount released by leaded gasoline combustion in all of Canada. Sharp decreases in the recent Pb fluxes to lake sediments indicate that the measures taken to mitigate metal emissions from the smelter were effective.

  8. Anthropogenic platinum and palladium in the sediments of Boston Harbor

    USGS Publications Warehouse

    Tuit, C.B.; Ravizza, G.E.; Bothner, Michael H.

    2000-01-01

    Anthropogenic activity has increased recent sediment concentrations of Pt and Pd in Boston Harbor by approximately 5 times background concentrations. Surface sediments and downcore profiles were investigated to evaluate Pt and Pd accumulation and behavior in urban coastal sediments. There is no clear correlation between temporal changes in Pt and Pd consumption and sediment concentration. However, Pt/Pb and Pd/Pb ratios suggest that Pt and Pd flux into the Harbor may not be decreasing with cessation of sludge input as rapidly as other metals. This is supported by the large discrepancy between fluxes associated with sludge and effluent release and those calculated from surface sediment concentrations. This evidence supports catalytic converters as a major source of Pd and Pt to Boston Harbor but cannot preclude other sources. Pd does not exhibit signs of post-burial remobilization below the mixed layer in the sediment cores, although near-surface variability in Pd concentrations may indicate a labile Pd component. Pt displays an inverse correlation with Mn above the oxic/suboxic transition, similar to behavior seen in pristine sediments where Pt is thought to be chemically mobile. This study does not support the use of Pd and Pt as tracers of recent contaminated sedimentation. However, the possibility of a labile Pt and Pd in these sediments highlights the need for further study of the biological uptake of these metals.Anthropogenic activity has increased recent sediment concentrations of Pt and Pd in Boston Harbor by approximately 5 times background concentrations. Surface sediments and downcore profiles were investigated to evaluate Pt and Pd accumulation and behavior in urban coastal sediments. There is no clear correlation between temporal changes in Pt and Pd consumption and sediment concentration. However, Pt/Pb and Pd/Pb ratios suggest that Pt and Pd flux into the Harbor may not be decreasing with cessation of sludge input as rapidly as other metals. This is

  9. The human footprint in the west: a large-scale analysis of anthropogenic impacts.

    PubMed

    Leu, Matthias; Hanser, Steven E; Knick, Steven T

    2008-07-01

    Anthropogenic features such as urbanization, roads, and power lines, are increasing in western United States landscapes in response to rapidly growing human populations. However, their spatial effects have not been evaluated. Our goal was to model the human footprint across the western United States. We first delineated the actual area occupied by anthropogenic features, the physical effect area. Next, we developed the human footprint model based on the ecological effect area, the zone influenced by features beyond their physical presence, by combining seven input models: three models quantified top-down anthropogenic influences of synanthropic predators (avian predators, domestic dog and cat presence risk), and four models quantified bottom-up anthropogenic influences on habitat (invasion of exotic plants, human-caused fires, energy extraction, and anthropogenic wildland fragmentation). Using independent bird population data, we found bird abundance of four synanthropic species to correlate positively with human footprint intensity and negatively for three of the six species influenced by habitat fragmentation. We then evaluated the extent of the human footprint in relation to terrestrial (ecoregions) and aquatic systems (major rivers and lakes), regional management and conservation status, physical environment, and temporal changes in human actions. The physical effect area of anthropogenic features covered 13% of the western United States with agricultural land (9.8%) being most dominant. High-intensity human footprint areas (class 8-10) overlapped highly productive low-elevation private landholdings and covered 7% of the western United States compared to 48% for low-intensity areas (class 1-3), which were confined to low-productivity high-elevation federal landholdings. Areas within 1 km of rivers were more affected by the human footprint compared to lakes. Percentage human population growth was higher in low-intensity human footprint areas. The disproportional

  10. The human footprint in the west: a large-scale analysis of anthropogenic impacts.

    USGS Publications Warehouse

    Leu, M.; Hanser, S.E.; Knick, S.T.

    2008-01-01

    Anthropogenic features such as urbanization, roads, and power lines, are increasing in western United States landscapes in response to rapidly growing human populations. However, their spatial effects have not been evaluated. Our goal was to model the human footprint across the western United States. We first delineated the actual area occupied by anthropogenic features, the physical effect area. Next, we developed the human footprint model based on the ecological effect area, the zone influenced by features beyond their physical presence, by combining seven input models: three models quantified top-down anthropogenic influences of synanthropic predators (avian predators, domestic dog and cat presence risk), and four models quantified bottom-up anthropogenic influences on habitat (invasion of exotic plants, human-caused fires, energy extraction, and anthropogenic wildland fragmentation). Using independent bird population data, we found bird abundance of four synanthropic species to correlate positively with human footprint intensity and negatively for three of the six species influenced by habitat fragmentation. We then evaluated the extent of the human footprint in relation to terrestrial (ecoregions) and aquatic systems (major rivers and lakes), regional management and conservation status, physical environment, and temporal changes in human actions. The physical effect area of anthropogenic features covered 13% of the western United States with agricultural land (9.8%) being most dominant. High-intensity human footprint areas (class 8-10) overlapped highly productive low-elevation private landholdings and covered 7% of the western United States compared to 48% for low-intensity areas (class 1-3), which were confined to low-productivity high-elevation federal landholdings. Areas within 1 km of rivers were more affected by the human footprint compared to lakes. Percentage human population growth was higher in low-intensity human footprint areas. The disproportional

  11. Systems and methods for reconfiguring input devices

    NASA Technical Reports Server (NTRS)

    Lancaster, Jeff (Inventor); De Mers, Robert E. (Inventor)

    2012-01-01

    A system includes an input device having first and second input members configured to be activated by a user. The input device is configured to generate activation signals associated with activation of the first and second input members, and each of the first and second input members are associated with an input function. A processor is coupled to the input device and configured to receive the activation signals. A memory coupled to the processor, and includes a reconfiguration module configured to store the input functions assigned to the first and second input members and, upon execution of the processor, to reconfigure the input functions assigned to the input members when the first input member is inoperable.

  12. Insect-plant interactions in anthropogenically transformed ecosystems

    Treesearch

    Evgeny V. Kultunov; Victor I. Ponomarev; Sergey I. Fedorenko

    1991-01-01

    Structural and functional changes in forests due to anthropogenic factors have a considerable impact on the interaction of phytophagous insects with the phytocenosis. Many features of these processes have yet to be investigated in the deciduous forest conditions of the forest-steppe zone. We investigated birch forests disturbed by anthropogenic factors in the middle...

  13. Anthropogenic nutrients and harmful algae in coastal waters.

    PubMed

    Davidson, Keith; Gowen, Richard J; Harrison, Paul J; Fleming, Lora E; Hoagland, Porter; Moschonas, Grigorios

    2014-12-15

    Harmful algal blooms (HABs) are thought to be increasing in coastal waters worldwide. Anthropogenic nutrient enrichment has been proposed as a principal causative factor of this increase through elevated inorganic and/or organic nutrient concentrations and modified nutrient ratios. We assess: 1) the level of understanding of the link between the amount, form and ratio of anthropogenic nutrients and HABs; 2) the evidence for a link between anthropogenically generated HABs and negative impacts on human health; and 3) the economic implications of anthropogenic nutrient/HAB interactions. We demonstrate that an anthropogenic nutrient-HAB link is far from universal, and where it has been demonstrated, it is most frequently associated with high biomass rather than low biomass (biotoxin producing) HABs. While organic nutrients have been shown to support the growth of a range of HAB species, insufficient evidence exists to clearly establish if these nutrients specifically promote the growth of harmful species in preference to benign ones, or if/how they influence toxicity of harmful species. We conclude that the role of anthropogenic nutrients in promoting HABs is site-specific, with hydrodynamic processes often determining whether blooms occur. We also find a lack of evidence of widespread significant adverse health impacts from anthropogenic nutrient-generated HABs, although this may be partly due to a lack of human/animal health and HAB monitoring. Detailed economic evaluation and cost/benefit analysis of the impact of anthropogenically generated HABs, or nutrient reduction schemes to alleviate them, is also frequently lacking.

  14. Anthropogenic calcium depletion: a unique threat to forest ecosystem health?

    Treesearch

    Paul G. Schaberg; Donald H. DeHayes; Gary J. Hawley

    2001-01-01

    Numerous anthropogenic factors can deplete calcium (Ca) from forest ecosystems. Because an adequate supply of Ca is needed to support fundamental biological functions, including cell membrane stability and stress response, the potential for Ca deficiency following the individual, cumulative, or potentially synergistic, influences of anthropogenic factors raises...

  15. Attributing human mortality during extreme heat waves to anthropogenic climate change

    NASA Astrophysics Data System (ADS)

    Mitchell, Daniel; Heaviside, Clare; Vardoulakis, Sotiris; Huntingford, Chris; Masato, Giacomo; Guillod, Benoit P.; Frumhoff, Peter; Bowery, Andy; Wallom, David; Allen, Myles

    2016-07-01

    It has been argued that climate change is the biggest global health threat of the 21st century. The extreme high temperatures of the summer of 2003 were associated with up to seventy thousand excess deaths across Europe. Previous studies have attributed the meteorological event to the human influence on climate, or examined the role of heat waves on human health. Here, for the first time, we explicitly quantify the role of human activity on climate and heat-related mortality in an event attribution framework, analysing both the Europe-wide temperature response in 2003, and localised responses over London and Paris. Using publicly-donated computing, we perform many thousands of climate simulations of a high-resolution regional climate model. This allows generation of a comprehensive statistical description of the 2003 event and the role of human influence within it, using the results as input to a health impact assessment model of human mortality. We find large-scale dynamical modes of atmospheric variability remain largely unchanged under anthropogenic climate change, and hence the direct thermodynamical response is mainly responsible for the increased mortality. In summer 2003, anthropogenic climate change increased the risk of heat-related mortality in Central Paris by ∼70% and by ∼20% in London, which experienced lower extreme heat. Out of the estimated ∼315 and ∼735 summer deaths attributed to the heatwave event in Greater London and Central Paris, respectively, 64 (±3) deaths were attributable to anthropogenic climate change in London, and 506 (±51) in Paris. Such an ability to robustly attribute specific damages to anthropogenic drivers of increased extreme heat can inform societal responses to, and responsibilities for, climate change.

  16. Anthropogenic Influences on the Physical State of Submicron Particulate Matter Over a Tropical Forest

    NASA Astrophysics Data System (ADS)

    Martin, S. T.

    2016-12-01

    The occurrence of non-liquid and liquid physical states of submicron atmospheric particulate matter (PM) downwind of an urban region in central Amazonia was investigated. Measurements were conducted during two Intensive Operating Periods (IOP1 and IOP2) that took place during the wet and dry seasons, respectively, of the GoAmazon2014/5 campaign. Air masses representing variable influences of background conditions, urban pollution, and regional and continental scale biomass burning passed over the research site. As the air masses varied, particle rebound fraction, which is an indicator of the mix of physical states in a sampled particle population, was measured in real time at ground level using an impactor apparatus. Micrographs collected by transmission electron microscopy confirmed that liquid particles adhered while non-liquid particles rebounded. Relative humidity (RH) was scanned to collect rebound curves. When the apparatus RH matched ambient RH, 95% of the particles were liquid as a campaign average, although this percentage dropped to as low as 60% during periods of anthropogenic influence. Secondary organic material, produced for the most part by the oxidation of volatile organic compounds emitted from the forest, was the largest source of liquid PM. Analyses of the mass spectra of the atmospheric PM by positive-matrix factorization (PMF) and of concentrations of carbon monoxide, total particle number, and oxides of nitrogen were used to identify time periods affected by anthropogenic influences, including both urban pollution and biomass burning. The occurrence of non-liquid PM correlated with these indicators of anthropogenic influence. A linear model having as output the rebound fraction and as input the PMF factor loadings explained up to 70% of the variance in the observed rebound fractions. Anthropogenic influences appear to favor non-liquid PM by providing molecular species that increase viscosity when internally mixed with background PM, by

  17. Long-term reductions in anthropogenic nutrients link to improvements in Chesapeake Bay habitat

    USGS Publications Warehouse

    Ruhl, H.; Rybicki, N.B.

    2010-01-01

    Great effort continues to focus on ecosystem restoration and reduction of nutrient inputs thought to be responsible, in part, for declines in estuary habitats worldwide. The ability of environmental policy to address restoration is limited, in part, by uncertainty in the relationships between costly restoration and benefits. Here, we present results from an 18-y field investigation (1990-2007) of submerged aquatic vegetation (SAV) community dynamics and water quality in the Potomac River, a major tributary of the Chesapeake Bay. River and anthropogenic discharges lower water clarity by introducing nutrients that stimulate phytoplankton and epiphyte growth as well as suspended sediments. Efforts to restore the Chesapeake Bay are often viewed as failing. Overall nutrient reduction and SAV restoration goals have not been met. In the Potomac River, however, reduced in situ nutrients, wastewater-treatment effluent nitrogen, and total suspended solids were significantly correlated to increased SAV abundance and diversity. Species composition and relative abundance also correlated with nutrient and water-quality conditions, indicating declining fitness of exotic species relative to native species during restoration. Our results suggest that environmental policies that reduce anthropogenic nutrient inputs do result in improved habitat quality, with increased diversity and native species abundances. The results also help elucidate why SAV cover has improved only in some areas of the Chesapeake Bay.

  18. Long-term reductions in anthropogenic nutrients link to improvements in Chesapeake Bay habitat.

    PubMed

    Ruhl, Henry A; Rybicki, Nancy B

    2010-09-21

    Great effort continues to focus on ecosystem restoration and reduction of nutrient inputs thought to be responsible, in part, for declines in estuary habitats worldwide. The ability of environmental policy to address restoration is limited, in part, by uncertainty in the relationships between costly restoration and benefits. Here, we present results from an 18-y field investigation (1990-2007) of submerged aquatic vegetation (SAV) community dynamics and water quality in the Potomac River, a major tributary of the Chesapeake Bay. River and anthropogenic discharges lower water clarity by introducing nutrients that stimulate phytoplankton and epiphyte growth as well as suspended sediments. Efforts to restore the Chesapeake Bay are often viewed as failing. Overall nutrient reduction and SAV restoration goals have not been met. In the Potomac River, however, reduced in situ nutrients, wastewater-treatment effluent nitrogen, and total suspended solids were significantly correlated to increased SAV abundance and diversity. Species composition and relative abundance also correlated with nutrient and water-quality conditions, indicating declining fitness of exotic species relative to native species during restoration. Our results suggest that environmental policies that reduce anthropogenic nutrient inputs do result in improved habitat quality, with increased diversity and native species abundances. The results also help elucidate why SAV cover has improved only in some areas of the Chesapeake Bay.

  19. Long-term reductions in anthropogenic nutrients link to improvements in Chesapeake Bay habitat

    PubMed Central

    Rybicki, Nancy B.

    2010-01-01

    Great effort continues to focus on ecosystem restoration and reduction of nutrient inputs thought to be responsible, in part, for declines in estuary habitats worldwide. The ability of environmental policy to address restoration is limited, in part, by uncertainty in the relationships between costly restoration and benefits. Here, we present results from an 18-y field investigation (1990–2007) of submerged aquatic vegetation (SAV) community dynamics and water quality in the Potomac River, a major tributary of the Chesapeake Bay. River and anthropogenic discharges lower water clarity by introducing nutrients that stimulate phytoplankton and epiphyte growth as well as suspended sediments. Efforts to restore the Chesapeake Bay are often viewed as failing. Overall nutrient reduction and SAV restoration goals have not been met. In the Potomac River, however, reduced in situ nutrients, wastewater-treatment effluent nitrogen, and total suspended solids were significantly correlated to increased SAV abundance and diversity. Species composition and relative abundance also correlated with nutrient and water-quality conditions, indicating declining fitness of exotic species relative to native species during restoration. Our results suggest that environmental policies that reduce anthropogenic nutrient inputs do result in improved habitat quality, with increased diversity and native species abundances. The results also help elucidate why SAV cover has improved only in some areas of the Chesapeake Bay. PMID:20823243

  20. Colored dissolved organic matter dynamics and anthropogenic influences in a major transboundary river and its coastal wetland

    PubMed Central

    Zeri, Christina; Dimitriou, Elias; Ding, Yan; Jaffé, Rudolf; Anagnostou, Emmanouil; Pitta, Elli; Mentzafou, Angeliki

    2015-01-01

    Abstract Most transboundary rivers and their wetlands are subject to considerable anthropogenic pressures associated with multiple and often conflicting uses. In the Eastern Mediterranean such systems are also particularly vulnerable to climate change, posing additional challenges for integrated water resources management. Comprehensive measurements of the optical signature of colored dissolved organic matter (CDOM) were combined with measurements of river discharges and water physicochemical and biogeochemical properties, to assess carbon dynamics, water quality, and anthropogenic influences in a major transboundary system of the Eastern Mediterranean, the Evros (or, Марица or, Meriç) river and its Ramsar protected coastal wetland. Measurements were performed over three years, in seasons characterized by different hydrologic conditions and along transects extending more than 70 km from the freshwater end‐member to two kilometers offshore in the Aegean Sea. Changes in precipitation, anthropogenic dissolved organic matter (DOM) inputs from the polluted Ergene tributary, and the irregular operation of a dam were key factors driving water quality, salinity regimes, and biogeochemical properties in the Evros delta and coastal waters. Marsh outwelling affected coastal carbon quality, but the influence of wetlands was often masked by anthropogenic DOM contributions. A distinctive five‐peak CDOM fluorescence signature was characteristic of upstream anthropogenic inputs and clearly tracked the influence of freshwater discharges on water quality. Monitoring of this CDOM fluorescence footprint could have direct applications to programs focusing on water quality and environmental assessment in this and other transboundary rivers where management of water resources remains largely ineffective. PMID:27656002

  1. Anthropogenic Cycles of Rare Earth Elements

    NASA Astrophysics Data System (ADS)

    Du, X.; Graedel, T. E.

    2009-12-01

    This research will develop quantitatively resolved anthropogenic cycles and in-use stocks for the rare earth metals specifically cerium, lanthanum and dysprosium in Japan, China, and the U.S. for the year of 2007. Rare earth elements (REE) is a group of 17 scare metals widely used in a growing number of emerging technologies and have been in high demand for emerging technologies as raw materials during past the three decades. New market participants from newly industrializing countries, primarily China, have had strong impacts on the demand of share. Consequently, the importance to sustain a reliable, steady, uninterrupted supply on global market triggered comprehensive research to recognize and understand the life cycles of rare earths. Moreover, because China plays a dominant role in mining production since 1990, it requires the assessment for the countries, which are almost completely dependent on imports from China with respect to rare earth resources. The study aims to analyze the flows and stocks of rare earth elements individually as elemental form in spite of their natural geological co-occurrence and mixed composition in applications. By applying the method of Material Flow Analysis (MFA) work has been done on evaluating current and historical flows of specific technologically significant materials, for example, copper, zinc, nickel, etc., determining the stocks available in different types of reservoirs (e.g., lithosphere, in-use) and the flows among the reservoirs, developing scenarios of possible futures of metal use, and assessing the environmental and policy implications of the results. Therefore, REE as a new target deserves inclusion because of its potential demand-supply conflict and importance to secure the competitive advantage of technical innovation in future. This work will generate a quantitatively resolved anthropogenic life cycle and in-use stocks for REE for the main target countries for a chosen year, 2007, providing flows and stocks from

  2. Zooplankton community resilience after press-type anthropogenic stress in temporary ponds.

    PubMed

    Angeler, David G; Moreno, José M

    2007-06-01

    Temporary ponds are physically disturbed environments that fluctuate on seasonal and interannual scales. These ecosystems are also susceptible to anthropogenic perturbation such as contamination inputs. However, the interactive effects of natural disturbance and anthropogenic stress on ecosystem processes and community dynamics have hardly been assessed in these ecosystem types. We used a multiple before-after control-impact (MBACI) design to study zooplankton community recovery from low and high inputs of a fire retardant in artificially constructed ponds over three hydroperiods. The retardant caused a decline in species richness and an increase in rotifers during summer and winter months relative to controls and pretreatment dates, and the duration of these changes varied among retardant treatments. In nonmetric, multidimensional scaling analyses the increased rotifer densities were reflected in loops that showed recurring deviations from and (upon collapse) approaches to reference conditions, while the effects of the anthropogenic stressor persisted in the ponds. The amplitudes of fluctuation followed no regular patterns; it varied with retardant treatment level and was higher in the third hydroperiod compared to the second in one of the treatments. From a temporal perspective, this non-dampened pattern suggests a new cause-effect mechanism for disturbance ecology, which we refer to as a "protracted press disturbance, roller coaster response" relationship. This model emphasizes stochastic oscillations in community composition, punctuated by periods in which the community approaches reference conditions. From the applied viewpoint, this model suggests that the accurate detection of perturbation and the implementation of sound management and restoration strategies will require intensive sampling designs that span multiple hydroperiods in persistently degraded ponds.

  3. Utility of soil linear alkylbenzenes to assess regional anthropogenic influences with special reference to atmospheric transport.

    PubMed

    Wei, Gao-Ling; Bao, Lian-Jun; Guo, Ling-Chuan; He, Zai-Cheng; Wu, Feng-Chang; Zeng, Eddy Y

    2014-07-15

    Tracing regional anthropogenic influences is important for assessing the magnitude of human interferences with the environment. In the present study, the utility of soil linear alkylbenzenes (LABs) as indicators of anthropogenic influences was examined, with the emphasis on the role of atmospheric transport in dissipating LABs from input sources to remote areas. The Pearl River Delta, South China, which has experienced rapid economic growth and urbanization, was selected as the study region. The concentrations of LABs (mean: 8.6 ng/g and median: 5.7 ng/g, with an outlier of 2,020 ng/g excluded) suggested that sewage contamination throughout the entire study region was generally light. The spatial variation of sewage pollution was significantly positively correlated with population density and per capita gross domestic product, with hot spots concentrated in the central PRD. Atmospheric deposition was hypothesized as an important input route for soil LABs in forestry and drinking water source areas with little impact of irrigation or direct wastewater discharge. This proposition could explain the opposite spatial patterns of LAB concentrations and values of a biodegradation index (5-C12+5-C13)/(5-C11+5-C10), where i-Cn defines a specific LAB congener with i and n indicating the position of the phenyl group and the number of carbon atoms on the alkyl chain, respectively. These findings somewhat validated LABs as tracers of regional anthropogenically derived contamination, with atmospheric transport of LABs as a viable dissipating mechanism. Copyright © 2014 Elsevier B.V. All rights reserved.

  4. Assessing the observed impact of anthropogenic climate change

    DOE PAGES

    Hansen, Gerrit; Stone, Dáithí

    2015-12-21

    Impacts of recent regional changes in climate on natural and human systems are documented across the globe, yet studies explicitly linking these observations to anthropogenic forcing of the climate are scarce. Here in this work, we provide a systematic assessment of the role of anthropogenic climate change for the range of impacts of regional climate trends reported in the IPCC’s Fifth Assessment Report. We find that almost two-thirds of the impacts related to atmospheric and ocean temperature can be confidently attributed to anthropogenic forcing. In contrast, evidence connecting changes in precipitation and their respective impacts to human influence is stillmore » weak. Moreover, anthropogenic climate change has been a major influence for approximately three-quarters of the impacts observed on continental scales. Finally, hence the effects of anthropogenic emissions can now be discerned not only globally, but also at more regional and local scales for a variety of natural and human systems.« less

  5. Assessing the observed impact of anthropogenic climate change

    SciTech Connect

    Hansen, Gerrit; Stone, Dáithí

    2015-12-21

    Impacts of recent regional changes in climate on natural and human systems are documented across the globe, yet studies explicitly linking these observations to anthropogenic forcing of the climate are scarce. Here in this work, we provide a systematic assessment of the role of anthropogenic climate change for the range of impacts of regional climate trends reported in the IPCC’s Fifth Assessment Report. We find that almost two-thirds of the impacts related to atmospheric and ocean temperature can be confidently attributed to anthropogenic forcing. In contrast, evidence connecting changes in precipitation and their respective impacts to human influence is still weak. Moreover, anthropogenic climate change has been a major influence for approximately three-quarters of the impacts observed on continental scales. Finally, hence the effects of anthropogenic emissions can now be discerned not only globally, but also at more regional and local scales for a variety of natural and human systems.

  6. Assessing the observed impact of anthropogenic climate change

    NASA Astrophysics Data System (ADS)

    Hansen, Gerrit; Stone, Dáithí

    2016-05-01

    Impacts of recent regional changes in climate on natural and human systems are documented across the globe, yet studies explicitly linking these observations to anthropogenic forcing of the climate are scarce. Here we provide a systematic assessment of the role of anthropogenic climate change for the range of impacts of regional climate trends reported in the IPCC’s Fifth Assessment Report. We find that almost two-thirds of the impacts related to atmospheric and ocean temperature can be confidently attributed to anthropogenic forcing. In contrast, evidence connecting changes in precipitation and their respective impacts to human influence is still weak. Moreover, anthropogenic climate change has been a major influence for approximately three-quarters of the impacts observed on continental scales. Hence the effects of anthropogenic emissions can now be discerned not only globally, but also at more regional and local scales for a variety of natural and human systems.

  7. An Ecological and Evolutionary Framework for Commensalism in Anthropogenic Environments.

    PubMed

    Hulme-Beaman, Ardern; Dobney, Keith; Cucchi, Thomas; Searle, Jeremy B

    2016-08-01

    Commensalism within anthropogenic environments has not been extensively discussed, despite its impact on humans, and there is no formal framework for assessing this ecological relationship in its varied forms. Here, we examine commensalism in anthropogenic environments in detail, considering both ecological and evolutionary drivers. The many assumptions about commensalism and the nature of anthropogenic environments are discussed and we highlight dependency as a key attribute of anthropogenic commensals (anthrodependent taxa). We primarily focus on mammalian species in the anthropogenic-commensal niche, but the traits described and selective pressures presented are likely fundamental to many species engaged in intense commensal relationships with humans. Furthermore, we demonstrate that this largely understudied interaction represents an important opportunity to investigate evolutionary processes in rapidly changing environments. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

  8. Definition and quantification of initial anthropogenic pollutant release in swimming pools.

    PubMed

    Keuten, M G A; Schets, F M; Schijven, J F; Verberk, J Q J C; van Dijk, J C

    2012-07-01

    Pollutants, brought into a swimming pool by bathers, will react with chlorine to form disinfection by-products (DBPs). Some of these DBPs are found to be respiratory and ocular irritant and might be associated with asthma, or might even be carcinogenic. As DBPs in swimming pools are formed from bather-shed-pollutants, a reduction of these pollutants will lead to a reduction of DBPs. Until now, however, the release of pollutants by bathers has not been studied in detail. The study described in this paper focuses on the release of these pollutants, further called anthropogenic pollutants. The objective was to define and quantify the initial anthropogenic pollutants, by using a standardised shower cabin and a standardised showering protocol in laboratory time-series experiments and on-site experiments in swimming pools. The time-series experiments resulted in a definition of the initial anthropogenic pollutant release: the amount of pollutants released from a person in a standardised shower cabin during the first 60 s of showering. The data from the time-series experiments were used to create a model of pollutant release. The model can be used to predict the initial anthropogenic pollutant release as well as the effects of showering. On-site experiments were performed at four different swimming pools, including one outdoor pool. Results of these on-site showering experiments correspond with the time-series and model outcomes. Anthropogenic pollutant release (both chemical and microbiological) in swimming pool water can be reduced by pre-swim showering, very likely resulting in decreased DBPs formation and chlorine demand. Copyright © 2012 Elsevier Ltd. All rights reserved.

  9. Artificial breakwaters as garbage bins: Structural complexity enhances anthropogenic litter accumulation in marine intertidal habitats.

    PubMed

    Aguilera, Moisés A; Broitman, Bernardo R; Thiel, Martin

    2016-07-01

    Coastal urban infrastructures are proliferating across the world, but knowledge about their emergent impacts is still limited. Here, we provide evidence that urban artificial reefs have a high potential to accumulate the diverse forms of litter originating from anthropogenic activities around cities. We test the hypothesis that the structural complexity of urban breakwaters, when compared with adjacent natural rocky intertidal habitats, is a driver of anthropogenic litter accumulation. We determined litter abundances at seven sites (cities) and estimated the structural complexity in both urban breakwaters and adjacent natural habitats from northern to central Chile, spanning a latitudinal gradient of ∼15° (18°S to 33°S). Anthropogenic litter density was significantly higher in coastal breakwaters when compared to natural habitats (∼15.1 items m(-2) on artificial reefs versus 7.4 items m(-2) in natural habitats) at all study sites, a pattern that was temporally persistent. Different litter categories were more abundant on the artificial reefs than in natural habitats, with local human population density and breakwater extension contributing to increase the probabilities of litter occurrence by ∼10%. In addition, structural complexity was about two-fold higher on artificial reefs, with anthropogenic litter density being highest at intermediate levels of structural complexity. Therefore, the spatial structure characteristic of artificial reefs seems to enhance anthropogenic litter accumulation, also leading to higher residence time and degradation potential. Our study highlights the interaction between coastal urban habitat modification by establishment of artificial reefs, and pollution. This emergent phenomenon is an important issue to be considered in future management plans and the engineering of coastal ecosystems.

  10. Lead poisoning

    MedlinePlus

    ... help if this information is not immediately available. Poison Control If someone has severe symptoms from possible ... be caused by lead poisoning, call your local poison control center. Your local poison center can be ...

  11. Anthropogenic ecosystem disturbance and the recovery debt

    PubMed Central

    Moreno-Mateos, David; Barbier, Edward B.; Jones, Peter C.; Jones, Holly P.; Aronson, James; López-López, José A.; McCrackin, Michelle L.; Meli, Paula; Montoya, Daniel; Rey Benayas, José M.

    2017-01-01

    Ecosystem recovery from anthropogenic disturbances, either without human intervention or assisted by ecological restoration, is increasingly occurring worldwide. As ecosystems progress through recovery, it is important to estimate any resulting deficit in biodiversity and functions. Here we use data from 3,035 sampling plots worldwide, to quantify the interim reduction of biodiversity and functions occurring during the recovery process (that is, the ‘recovery debt'). Compared with reference levels, recovering ecosystems run annual deficits of 46–51% for organism abundance, 27–33% for species diversity, 32–42% for carbon cycling and 31–41% for nitrogen cycling. Our results are consistent across biomes but not across degrading factors. Our results suggest that recovering and restored ecosystems have less abundance, diversity and cycling of carbon and nitrogen than ‘undisturbed' ecosystems, and that even if complete recovery is reached, an interim recovery debt will accumulate. Under such circumstances, increasing the quantity of less-functional ecosystems through ecological restoration and offsetting are inadequate alternatives to ecosystem protection. PMID:28106039

  12. Natural versus anthropogenic subsidence of Venice

    PubMed Central

    Tosi, Luigi; Teatini, Pietro; Strozzi, Tazio

    2013-01-01

    We detected land displacements of Venice by Persistent Scatterer Interferometry using ERS and ENVISAT C-band and TerraSAR-X and COSMO-SkyMed X-band acquisitions over the periods 1992–2010 and 2008–2011, respectively. By reason of the larger observation period, the C-band sensors was used to quantify the long-term movements, i.e. the subsidence component primarily ascribed to natural processes. The high resolution X-band satellites reveal a high effectiveness to monitor short-time movements as those induced by human activities. Interpolation of the two datasets and removal of the C-band from the X-band map allows discriminating between the natural and anthropogenic components of the subsidence. A certain variability characterizes the natural subsidence (0.9 ± 0.7 mm/yr), mainly because of the heterogeneous nature and age of the lagoon subsoil. The 2008 displacements show that man interventions are responsible for movements ranging from −10 to 2 mm/yr. These displacements are generally local and distributed along the margins of the city islands. PMID:24067871

  13. Modeling fallout of anthropogenic 129I.

    PubMed

    Englund, Edvard; Aldahan, Ala; Possnert, Göran; Haltia-Hovi, Eeva; Hou, Xiaolin; Renberg, Ingmar; Saarinen, Timo

    2008-12-15

    Despite the relatively well-recognized emission rates of the anthropogenic 129I, there is little knowledge about the temporal fallout patterns and magnitude of fluxes since the start of the atomic era atthe early 1940s. We here present measurements of annual 129I concentrations in sediment archives from Sweden and Finland covering the period 1942-2006. The results revealed impression of 129I emissions from the nuclear reprocessing facility at Sellafield and La Hague and a clear Chernobyl fallout enhancement during 1986. In order to estimate relative contributions from the different sources, a numerical model approach was used taking into accountthe emission rates/estimated fallout, transport pathways, and the sediment system. The model outcomes suggest a relatively dominating marine source of 129I to north Europe compared to direct gaseous releases. A transfer rate of 129I from sea to atmosphere is derived for pertinent sea areas (English Channel, Irish Sea, and North Sea), which is estimated at 0.04 to 0.21 y(-1).

  14. Anthropogenic Pu distribution in Tropical East Pacific.

    PubMed

    Kinoshita, Norikazu; Sumi, Takahiro; Takimoto, Kiyotaka; Nagaoka, Mika; Yokoyama, Akihiko; Nakanishi, Takashi

    2011-04-15

    The geographical distribution of the anthropogenic radionuclides (238)Pu and (239+240)Pu in the Tropical East Pacific in 2003 was studied from the viewpoint of material migration. We measured the contents of Pu isotopes in seawater and in sediment from the sea bottom. The distributions of Pu isotopes, together with those of coexisting nitrate and phosphate species and dissolved oxygen, are discussed in relation to the potential temperature and potential density (sigma-θ). The Pu contents in sediment samples were compared with those in the seawater. Horizontal migration across the Equator from north to south was investigated at depths down to ~800m in the eastern Pacific. The Pu distribution at 0-400m correlated well with the distribution of potential temperature. Maximum Pu levels were observed in the subsurface layer at 600-800m, corresponding to the depth where sigma-θ≈27.0. It is suggested that the Pu distribution depends on the structure of the water mass and the particular temperature and salinity. The water column/sediment column inventory ratio and the vertical distribution of Pu may reflect the efficiency of scavenging in the relevant water areas. Copyright © 2011 Elsevier B.V. All rights reserved.

  15. Anthropogenic atmospheric emissions of cadmium in China

    NASA Astrophysics Data System (ADS)

    Shao, Xiao; Cheng, Hongguang; Li, Qian; Lin, Chunye

    2013-11-01

    In this study, we estimated atmospheric Cd emissions from anthropogenic sources in China from 1990 to 2010 on the basis of consumption or output data and emission factors. China emitted approximately 2186 t Cd to the atmosphere in 2010, with approximately 77% and 14% of the emissions arising from non-ferrous metal smelting and coal combustion, respectively. Temporal changes in the total Cd emissions were characterized by two periods of increase (1990-2000 and 2001-2010) and a short period of decrease (2000-2001) due to application of energy-saving and cleaner production technologies. Overall, atmospheric Cd emissions increased from 474 t in 1990 to 2186 t in 2010 due to rapid economic growth, whereas energy-saving and cleaner production technologies have been in use since 2000. Spatial distribution of the atmospheric Cd emissions was dominated primarily by non-ferrous metal smelting and coal combustion. Emissions are high in Hunan and Yunnan Provinces because of high production non-ferrous metal smelting and in Shandong Province because of high coal consumption and moderate non-ferrous metal production.

  16. Anthropogenic warming of Earth's climate system.

    PubMed

    Levitus, S; Antonov, J I; Wang, J; Delworth, T L; Dixon, K W; Broccoli, A J

    2001-04-13

    We compared the temporal variability of the heat content of the world ocean, of the global atmosphere, and of components of Earth's cryosphere during the latter half of the 20th century. Each component has increased its heat content (the atmosphere and the ocean) or exhibited melting (the cryosphere). The estimated increase of observed global ocean heat content (over the depth range from 0 to 3000 meters) between the 1950s and 1990s is at least one order of magnitude larger than the increase in heat content of any other component. Simulation results using an atmosphere-ocean general circulation model that includes estimates of the radiative effects of observed temporal variations in greenhouse gases, sulfate aerosols, solar irradiance, and volcanic aerosols over the past century agree with our observation-based estimate of the increase in ocean heat content. The results we present suggest that the observed increase in ocean heat content may largely be due to the increase of anthropogenic gases in Earth's atmosphere.

  17. Anthropogenic ecosystem disturbance and the recovery debt.

    PubMed

    Moreno-Mateos, David; Barbier, Edward B; Jones, Peter C; Jones, Holly P; Aronson, James; López-López, José A; McCrackin, Michelle L; Meli, Paula; Montoya, Daniel; Rey Benayas, José M

    2017-01-20

    Ecosystem recovery from anthropogenic disturbances, either without human intervention or assisted by ecological restoration, is increasingly occurring worldwide. As ecosystems progress through recovery, it is important to estimate any resulting deficit in biodiversity and functions. Here we use data from 3,035 sampling plots worldwide, to quantify the interim reduction of biodiversity and functions occurring during the recovery process (that is, the 'recovery debt'). Compared with reference levels, recovering ecosystems run annual deficits of 46-51% for organism abundance, 27-33% for species diversity, 32-42% for carbon cycling and 31-41% for nitrogen cycling. Our results are consistent across biomes but not across degrading factors. Our results suggest that recovering and restored ecosystems have less abundance, diversity and cycling of carbon and nitrogen than 'undisturbed' ecosystems, and that even if complete recovery is reached, an interim recovery debt will accumulate. Under such circumstances, increasing the quantity of less-functional ecosystems through ecological restoration and offsetting are inadequate alternatives to ecosystem protection.

  18. National Hospital Input Price Index

    PubMed Central

    Freeland, Mark S.; Anderson, Gerard; Schendler, Carol Ellen

    1979-01-01

    The national community hospital input price index presented here isolates the effects of prices of goods and services required to produce hospital care and measures the average percent change in prices for a fixed market basket of hospital inputs. Using the methodology described in this article, weights for various expenditure categories were estimated and proxy price variables associated with each were selected. The index is calculated for the historical period 1970 through 1978 and forecast for 1979 through 1981. During the historical period, the input price index increased an average of 8.0 percent a year, compared with an average rate of increase of 6.6 percent for overall consumer prices. For the period 1979 through 1981, the average annual increase is forecast at between 8.5 and 9.0 percent. Using the index to deflate growth in expenses, the level of real growth in expenditures per inpatient day (net service intensity growth) averaged 4.5 percent per year with considerable annual variation related to government and hospital industry policies. PMID:10309052

  19. National hospital input price index.

    PubMed

    Freeland, M S; Anderson, G; Schendler, C E

    1979-01-01

    The national community hospital input price index presented here isolates the effects of prices of goods and services required to produce hospital care and measures the average percent change in prices for a fixed market basket of hospital inputs. Using the methodology described in this article, weights for various expenditure categories were estimated and proxy price variables associated with each were selected. The index is calculated for the historical period 1970 through 1978 and forecast for 1979 through 1981. During the historical period, the input price index increased an average of 8.0 percent a year, compared with an average rate of increase of 6.6 percent for overall consumer prices. For the period 1979 through 1981, the average annual increase is forecast at between 8.5 and 9.0 per cent. Using the index to deflate growth in expenses, the level of real growth in expenditures per inpatient day (net service intensity growth) averaged 4.5 percent per year with considerable annual variation related to government and hospital industry policies.

  20. Natural versus anthropogenic dispersion of metals to the environment in the Wulik River area, western Brooks Range, northern Alaska

    USGS Publications Warehouse

    Kelley, K.D.; Hudson, T.

    2007-01-01

    Zinc-lead-silver mineral deposits in the Wulik River region, Alaska, contain an enormous accumulation of Zn. In addition to the giant deposits at Red Dog, at least nine other deposits are known. Natural weathering of these deposits has dispersed metals over a wide region over a long period of time (c. 10 000 years) through transport by stream and groundwater, stream sediments, formation of soils, and perhaps wind-blown atmospheric deposition from weathering of naturally enriched Pb-Zn surface deposits. Anthropogenic input also contributes metals to the environment. Mining of the Red Dog deposit, which began in 1989, produces fine-grained galena and sphalerite concentrates that are transported from the mine site by truck to a storage port facility. Wind-blown dispersion of concentrate dust along the road and around the port facility has been a source of local metal-rich surficial materials. Geochemical and mineralogical characteristics provide a means of distinguishing the natural versus anthropogenic metal sources. Soils over deposits have patterns of increasing metal contents with depth and proximity to the metal-bearing source, whereas ore concentrate dust is localized at the surface. The acidity produced by weathering of the sulphide deposits creates an environment in which elements such as Se and Mo are stable whereas Ca is not. Consequently, high Mo (up to 29 ppm) and Se (up to 17 ppm) and low Ca (<0.4%) concentrations characterize surficial materials near natural deposits. Acidic conditions also yield high Pb-Zn ratios (up to 70) because sphalerite is preferentially dissolved and Zn is mobilized during chemical weathering. In natural materials, secondary jarosite and anglesite are developed, and minor galena is etched and rounded due to a history of chemical and mechanical weathering. In contrast, dust-bearing samples have Pb/Zn ratios that are 0.4 or less, Ca contents are higher (0.2 to 3.6%), and Mo (<10 ppm) and Se (not detected) concentrations are low

  1. Lead isotopes tracing the life cycle of a catchment: From source rock via weathering to human impact

    NASA Astrophysics Data System (ADS)

    Negrel, P. J.; Petelet-Giraud, E.; Guerrot, C.; Millot, R.

    2015-12-01

    Chemical weathering of rocks involves consumption of CO2, a greenhouse gas with a strong influence on climate. Among rocks exposed to weathering, basalt plays a major role in the carbon cycle as it is more easily weathered than other crystalline silicate rocks. This means that basalt weathering acts as a major atmospheric CO2 sink. The present study investigated the lead isotopes in rock, soil and sediment for constraining the life cycle of a catchment, covering source rocks, erosion processes and products, and anthropogenic activities. For this, we investigated the Allanche river drainage basin in the Massif Central, the largest volcanic areas in France, that offers opportunities for selected geochemical studies since it drains a single type of virtually unpolluted volcanic rock, with agricultural activity increasing downstream. Soil and sediment are derived exclusively from basalt weathering, and their chemistry, coupled to isotope tracing, should shed light on the behavior of chemical species during weathering from parental bedrock. Bedrock samples of the basin, compared to regional bedrock of the volcanic province, resulted from a complex history and multiple mantle reservoir sources and mixing. Regarding soils and sediments, comparison of Pb and Zr normalized to mobile K shows a linear evolution of weathering processes, whereby lead enrichment from atmospheric deposition is the other major contributor. Lead-isotope ratios showed that most of the lead budget in sediment and soil results from bedrock weathering with an influence of past mining and mineral processing of ores in the Massif Central, and deposition of lead-rich particles from gasoline combustion, but no lead input from agricultural activity. A classic box model was used to investigate the dynamics of sediment transfer at the catchment scale, the lead behavior in the continuum bedrock-soil-sediment and the historical evolution of anthropogenic aerosol emissions.

  2. Formation of nanoparticles of blue haze enhanced by anthropogenic pollution.

    PubMed

    Zhang, Renyi; Wang, Lin; Khalizov, Alexei F; Zhao, Jun; Zheng, Jun; McGraw, Robert L; Molina, Luisa T

    2009-10-20

    The molecular processes leading to formation of nanoparticles of blue haze over forested areas are highly complex and not fully understood. We show that the interaction between biogenic organic acids and sulfuric acid enhances nucleation and initial growth of those nanoparticles. With one cis-pinonic acid and three to five sulfuric acid molecules in the critical nucleus, the hydrophobic organic acid part enhances the stability and growth on the hydrophilic sulfuric acid counterpart. Dimers or heterodimers of biogenic organic acids alone are unfavorable for new particle formation and growth because of their hydrophobicity. Condensation of low-volatility organic acids is hindered on nano-sized particles, whereas ammonia contributes negligibly to particle growth in the size range of 3-30 nm. The results suggest that initial growth from the critical nucleus to the detectable size of 2-3 nm most likely occurs by condensation of sulfuric acid and water, implying that anthropogenic sulfur emissions (mainly from power plants) strongly influence formation of terrestrial biogenic particles and exert larger direct and indirect climate forcing than previously recognized.

  3. Formation of nanoparticles of blue haze enhanced by anthropogenic pollution

    PubMed Central

    Zhang, Renyi; Wang, Lin; Khalizov, Alexei F.; Zhao, Jun; Zheng, Jun; McGraw, Robert L.; Molina, Luisa T.

    2009-01-01

    The molecular processes leading to formation of nanoparticles of blue haze over forested areas are highly complex and not fully understood. We show that the interaction between biogenic organic acids and sulfuric acid enhances nucleation and initial growth of those nanoparticles. With one cis-pinonic acid and three to five sulfuric acid molecules in the critical nucleus, the hydrophobic organic acid part enhances the stability and growth on the hydrophilic sulfuric acid counterpart. Dimers or heterodimers of biogenic organic acids alone are unfavorable for new particle formation and growth because of their hydrophobicity. Condensation of low-volatility organic acids is hindered on nano-sized particles, whereas ammonia contributes negligibly to particle growth in the size range of 3–30 nm. The results suggest that initial growth from the critical nucleus to the detectable size of 2–3 nm most likely occurs by condensation of sulfuric acid and water, implying that anthropogenic sulfur emissions (mainly from power plants) strongly influence formation of terrestrial biogenic particles and exert larger direct and indirect climate forcing than previously recognized. PMID:19815498

  4. Anthropogenic influence on the distribution of tropospheric sulphate aerosol

    NASA Astrophysics Data System (ADS)

    Langner, J.; Rodhe, H.; Crutzen, P. J.; Zimmermann, P.

    1992-10-01

    HUMAN activities have increased global emissions of sulphur gases by about a factor of three during the past century, leading to increased sulphate aerosol concentrations, mainly in the Northern Hemisphere. Sulphate aerosols can affect the climate directly, by increasing the backscattering of solar radiation in cloud-free air, and indirectly, by providing additional cloud condensation nuclei1-4. Here we use a global transport-chemistry model to estimate the changes in the distribution of tropospheric sulphate aerosol and deposition of non-seasalt sulphur that have occurred since pre-industrial times. The increase in sulphate aerosol concentration is small over the Southern Hemisphere oceans, but reaches a factor of 100 over northern Europe in winter. Our calculations indicate, however, that at most 6% of the anthropogenic sulphur emissions is available for the formation of new aerosol particles. This is because about one-half of the sulphur dioxide is deposited on the Earth's surface, and most of the remainder is oxidized in cloud droplets so that the sulphate becomes associated with pre-existing particles. Even so, the rate of formation of new sulphate particles may have doubled since pre-industrial times.

  5. Detecting regional anthropogenic trends in ocean acidification against natural variability

    NASA Astrophysics Data System (ADS)

    Friedrich, T.; Timmermann, A.; Abe-Ouchi, A.; Bates, N. R.; Chikamoto, M. O.; Church, M. J.; Dore, J. E.; Gledhill, D. K.; González-Dávila, M.; Heinemann, M.; Ilyina, T.; Jungclaus, J. H.; McLeod, E.; Mouchet, A.; Santana-Casiano, J. M.

    2012-03-01

    Since the beginning of the Industrial Revolution humans have released ~500 billion metric tons of carbon to the atmosphere through fossil-fuel burning, cement production and land-use changes. About 30% has been taken up by the oceans. The oceanic uptake of carbon dioxide leads to changes in marine carbonate chemistry resulting in a decrease of seawater pH and carbonate ion concentration, commonly referred to as ocean acidification. Ocean acidification is considered a major threat to calcifying organisms. Detecting its magnitude and impacts on regional scales requires accurate knowledge of the level of natural variability of surface ocean carbonate ion concentrations on seasonal to annual timescales and beyond. Ocean observations are severely limited with respect to providing reliable estimates of the signal-to-noise ratio of human-induced trends in carbonate chemistry against natural factors. Using three Earth system models we show that the current anthropogenic trend in ocean acidification already exceeds the level of natural variability by up to 30 times on regional scales. Furthermore, it is demonstrated that the current rates of ocean acidification at monitoring sites in the Atlantic and Pacific oceans exceed those experienced during the last glacial termination by two orders of magnitude.

  6. Anthropogenic Chromium Emissions in China from 1990 to 2009

    PubMed Central

    Cheng, Hongguang; Zhou, Tan; Li, Qian; Lu, Lu; Lin, Chunye

    2014-01-01

    An inventory of chromium emission into the atmosphere and water from anthropogenic activities in China was compiled for 1990 through to 2009. We estimate that the total emission of chromium to the atmosphere is about 1.92×105t. Coal and oil combustion were the two leading sources of chromium emission to the atmosphere in China, while the contribution of them showed opposite annual growth trend. In total, nearly 1.34×104t of chromium was discharged to water, mainly from six industrial categories in 20 years. Among them, the metal fabrication industry and the leather tanning sector were the dominant sources of chromium emissions, accounting for approximately 68.0% and 20.0% of the total emissions and representing increases of15.6% and 10.3% annually, respectively. The spatial trends of Cr emissions show significant variation based on emissions from 2005 to 2009. The emission to the atmosphere was heaviest in Hebei, Shandong, Guangdong, Zhejiang and Shanxi, whose annual emissions reached more than 1000t for the high level of coal and oil consumption. In terms of emission to water, the largest contributors were Guangdong, Jiangsu, Shandong and Zhejiang, where most of the leather production and metal manufacturing occur and these four regions accounted for nearly 47.4% of the total emission to water. PMID:24505309

  7. Anthropogenic chromium emissions in china from 1990 to 2009.

    PubMed

    Cheng, Hongguang; Zhou, Tan; Li, Qian; Lu, Lu; Lin, Chunye

    2014-01-01

    An inventory of chromium emission into the atmosphere and water from anthropogenic activities in China was compiled for 1990 through to 2009. We estimate that the total emission of chromium to the atmosphere is about 1.92×10⁵ t. Coal and oil combustion were the two leading sources of chromium emission to the atmosphere in China, while the contribution of them showed opposite annual growth trend. In total, nearly 1.34×10⁴ t of chromium was discharged to water, mainly from six industrial categories in 20 years. Among them, the metal fabrication industry and the leather tanning sector were the dominant sources of chromium emissions, accounting for approximately 68.0% and 20.0% of the total emissions and representing increases of 15.6% and 10.3% annually, respectively. The spatial trends of Cr emissions show significant variation based on emissions from 2005 to 2009. The emission to the atmosphere was heaviest in Hebei, Shandong, Guangdong, Zhejiang and Shanxi, whose annual emissions reached more than 1000t for the high level of coal and oil consumption. In terms of emission to water, the largest contributors were Guangdong, Jiangsu, Shandong and Zhejiang, where most of the leather production and metal manufacturing occur and these four regions accounted for nearly 47.4% of the total emission to water.

  8. Impact of Anthropogenic Disturbance on Native and Invasive Trypanosomes of Rodents in Forested Uganda.

    PubMed

    Salzer, Johanna S; Pinto, C Miguel; Grippi, Dylan C; Williams-Newkirk, Amanda Jo; Peterhans, Julian Kerbis; Rwego, Innocent B; Carroll, Darin S; Gillespie, Thomas R

    2016-12-01

    Habitat disturbance and anthropogenic change are globally associated with extinctions and invasive species introductions. Less understood is the impact of environmental change on the parasites harbored by endangered, extinct, and introduced species. To improve our understanding of the impacts of anthropogenic disturbance on such host-parasite interactions, we investigated an invasive trypanosome (Trypanosoma lewisi). We screened 348 individual small mammals, representing 26 species, from both forested and non-forested habitats in rural Uganda. Using microscopy and PCR, we identified 18% of individuals (order Rodentia) as positive for trypanosomes. Further phylogenetic analyses revealed two trypanosomes circulating-T. lewisi and T. varani. T. lewisi was found in seven species both native and invasive, while T. varani was identified in only three native forest species. The lack of T. varani in non-forested habitats suggests that it is a natural parasite of forest-dwelling rodents. Our findings suggest that anthropogenic disturbance may lead to spillover of an invasive parasite (T. lewisi) from non-native to native species, and lead to local co-extinction of a native parasite (T. varani) and native forest-dwelling hosts.

  9. A 100-year sedimentary record of natural and anthropogenic impacts on a shallow eutrophic lake, Lake Chaohu, China.

    PubMed

    Zan, Fengyu; Huo, Shouliang; Xi, Beidou; Zhu, Chaowei; Liao, Haiqing; Zhang, Jingtian; Yeager, Kevin M

    2012-03-01

    In this study, the sediment profiles of total organic carbon, total nitrogen, C/N ratios, total phosphorus, N/P ratios, C/P ratios, particle sizes, and stable carbon and nitrogen isotopes (δ(13)C and δ(15)N) were used to investigate natural and anthropogenic impacts on Lake Chaohu over the past 100 years. Before 1960, Lake Chaohu experienced low productivity and a relatively steady and low nutrient input. The increasing concentration and fluxes of total organic carbon, total nitrogen, total phosphorus, together with changes in the δ(13)C and δ(15)N of organic material in the sediment cores, suggested that the anthropogenic effects on trophic status first started because of an increase in nutrient input caused by a population increase in the drainage area. With the construction of the Chaohu Dam, an increase in the utilization of fertilizer and the population growth which occurred since 1960, stable depositional conditions and increasing nutrient input resulted in a dominantly algae-derived organic matter source and high productivity. Nutrient input increased most significantly around 1980 following the rapidly growing population, with concomitant urbanization, industrial and agricultural development. This study also revealed that the concentration and distribution of nutrients varied between different areas of sediment within Lake Chaohu because of the influence of different drainage basins and pollution sources.

  10. Tracing sewage and natural freshwater input in a northwest Mediterranean Bay: evidence obtained from isotopic ratios in marine organisms.

    PubMed

    Lassauque, J; Lepoint, G; Thibaut, T; Francour, P; Meinesz, A

    2010-06-01

    Elemental carbon and nitrogen levels and isotope ratios were assessed in different biological compartments of a Northwest (NW) Mediterranean bay to trace the various sources of nutrient input from natural (river runoffs) and anthropogenic (harbor outflows, fish farms and urban sewage outfall) sources. Samples from transplanted mussels and natural sea grass communities (Posidonia oceanica leaves and epiphytes) were harvested from different locations throughout the bay during the touristic summer and rainy seasons. The results from the nitrogen analysis revealed that sewage and harbor outflow promote higher nitrogen levels, enrichment of (15)N in the tissues, and a higher seasonal variability in sea grass and epiphytes. In mussel tissues, the delta(15)N was also influenced by sewage and harbor outflow, whereas delta(13)C was influenced by terrestrial inputs. These results suggest that natural and anthropogenic nutrient inputs have a temporary and localized influence and affect the sensitivity of natural isotopic ratios to changes in hydrologic conditions, especially to rain and tourism.

  11. Experimental assessment of critical anthropogenic sediment burial in eelgrass Zostera marina.

    PubMed

    Munkes, Britta; Schubert, Philipp R; Karez, Rolf; Reusch, Thorsten B H

    2015-11-15

    Seagrass meadows, one of the world's most important and productive coastal habitats, are threatened by a range of anthropogenic actions. Burial of seagrass plants due to coastal activities is one important anthropogenic pressure leading to the decline of local populations. In our study, we assessed the response of eelgrass Zostera marina to sediment burial from physiological, morphological, and population parameters. In a full factorial field experiment, burial level (5-20cm) and burial duration (4-16weeks) were manipulated. Negative effects were visible even at the lowest burial level (5cm) and shortest duration (4weeks), with increasing effects over time and burial level. Buried seagrasses showed higher shoot mortality, delayed growth and flowering and lower carbohydrate storage. The observed effects will likely have an impact on next year's survival of buried plants. Our results have implications for the management of this important coastal plant.

  12. Attenuating initial beliefs: increasing the acceptance of anthropogenic climate change information by reflecting on values.

    PubMed

    van Prooijen, Anne-Marie; Sparks, Paul

    2014-05-01

    Anthropogenic climate change information tends to be interpreted against the backdrop of initial environmental beliefs, which can lead to some people being resistant toward the information. In this article (N = 88), we examined whether self-affirmation via reflection on personally important values could attenuate the impact of initial beliefs on the acceptance of anthropogenic climate change evidence. Our findings showed that initial beliefs about the human impact on ecological stability influenced the acceptance of information only among nonaffirmed participants. Self-affirmed participants who were initially resistant toward the information showed stronger beliefs in the existence of climate change risks and greater acknowledgment that individual efficacy has a role to play in reducing climate change risks than did their nonaffirmed counterparts. © 2013 Society for Risk Analysis.

  13. Is it possible to disentangle natural and anthropogenic forms of channel adjustment in dynamic floodplain wetlands?

    NASA Astrophysics Data System (ADS)

    Ralph, Timothy; Larkin, Zacchary; Hesse, Paul; Westaway, Kira; Heijnis, Henk

    2014-05-01

    Anthropogenic impacts on hydrology and sediment supply are recognized as leading factors contributing to change in many rivers and wetlands. However it is difficult to distinguish between key causes and forms of channel adjustment in fluvial systems where intrinsic geomorphic processes lead to change on a timeframe similar to that of human disturbance. In the Macquarie Marshes, a large (circa 2,500 square kilometres) floodplain wetland in southeastern Australia, intermittent flooding drives sedimentation and erosion leading to levee development, avulsion and floodout. Some contemporary channel change is attributed to human disturbance in the system (e.g. channel incision), which, together with river regulation and recent droughts, have left much of the floodplain high and dry. Distributary channels formed since European settlement in the early 19th century have low sinuosity (1.1 to 1.2), show little evidence of lateral migration, accumulate fine sediment rapidly (0.5 to 10 mm/yr) in levees and floodouts, and avulse or terminate in wetlands. Avulsion appears to occur rapidly; within 100 years. In contrast, the older, discontinuous trunk stream of the lower Macquarie River is more sinuous (1.3 to 1.5) and there is abundant evidence of lateral migration over time followed by levee development on top of ridges and swales. ITRAX core scanning and XRF from sediment profiles in a Macquarie River meander abandoned around 1 ka and subsequently filled with overbank fines revealed no laminations and no evidence of significant geochemical enrichment near the surface that is usually associated with anthropogenic sources (e.g. Pb and Cu). These results indicate a transition in depositional regime and channel adjustment processes from lateral migration to vertical accretion with greater levee development and avulsion in the late Holocene. A clear anthropogenic signal was not found in the sediment record, despite earthworks and other activities contributing to channel change. We

  14. Anthropogenic CO2 emissions in Africa

    NASA Astrophysics Data System (ADS)

    Canadell, J. G.; Raupach, M. R.; Houghton, R. A.

    2008-11-01

    An understanding of the regional contributions and trends of anthropogenic carbon dioxide (CO2) emissions is critical to design mitigation strategies aimed at stabilizing atmospheric greenhouse gases. Here we report CO2 emissions from the combustion of fossil fuels and land use change in Africa for various time periods. Africa was responsible for an average of 500 TgC y-1 for the period 2000 2005. These emissions resulted from the combustion of fossil fuels (260 TgC y-1) and land use change (240 TgC y-1). Over this period, the African share of global emissions from land use change was 17%. For 2005, the last year reported in this study, African fossil fuel emissions were 285 TgC accounting for 3.7% of the global emissions. The 2000 2005 growth rate in African fossil fuel emissions was 3.2% y-1, very close to the global average. Fossil fuel emissions per capita in Africa are among the lowest in the world, at 0.32 tC y-1 compared to the global average of 1.2 tC y-1. The average amount of carbon (C) emitted as CO2 to produce 1 US of Gross Domestic Product (GDP) in Africa in 2005 was 187 gC/, close to the world average of 199 gC/. With the fastest population growth in the world and rising per capita GDP, Africa is likely to increase its share of global emissions over the coming decades although emissions from Africa will remain low compared to other continents.

  15. Anthropogenic CO2 emissions in Africa

    NASA Astrophysics Data System (ADS)

    Canadell, J. G.; Raupach, M. R.; Houghton, R. A.

    2009-03-01

    An understanding of the regional contributions and trends of anthropogenic carbon dioxide (CO2) emissions is critical to design mitigation strategies aimed at stabilizing atmospheric greenhouse gases. Here we report CO2 emissions from the combustion of fossil fuels and land use change in Africa for various time periods. Africa was responsible for an average of 500 Tg C y-1 for the period 2000-2005. These emissions resulted from the combustion of fossil fuels (260 Tg C y-1) and land use change (240 Tg C y-1). Over this period, the African share of global emissions from land use change was 17%. For 2005, the last year reported in this study, African fossil fuel emissions were 285 Tg C accounting for 3.7% of the global emissions. The 2000-2005 growth rate in African fossil fuel emissions was 3.2% y-1, very close to the global average. Fossil fuel emissions per capita in Africa are among the lowest in the world, at 0.32 t C y-1 compared to the global average of 1.2 t C y-1. The average amount of carbon (C) emitted as CO2 to produce 1 US{} of Gross Domestic Product (GDP) in Africa was 187 g C/ in 2005, close to the world average of 199 g C/. With the fastest population growth in the world and rising per capita GDP, Africa is likely to increase its share of global emissions over the coming decades although emissions from Africa will remain low compared to other continents.

  16. Ecotoxicology: Lead

    USGS Publications Warehouse

    Scheuhammer, A.M.; Beyer, W.N.; Schmitt, C.J.; Jorgensen, Sven Erik; Fath, Brian D.

    2008-01-01

    Lead (Pb) is a naturally occurring metallic element; trace concentrations are found in all environmental media and in all living things. However, certain human activities, especially base metal mining and smelting; combustion of leaded gasoline; the use of Pb in hunting, target shooting, and recreational angling; the use of Pb-based paints; and the uncontrolled disposal of Pb-containing products such as old vehicle batteries and electronic devices have resulted in increased environmental levels of Pb, and have created risks for Pb exposure and toxicity in invertebrates, fish, and wildlife in some ecosystems.

  17. Occurrence, sources and transport pathways of natural and anthropogenic hydrocarbons in deep-sea sediments of the eastern Mediterranean Sea

    NASA Astrophysics Data System (ADS)

    Parinos, C.; Gogou, A.; Bouloubassi, I.; Pedrosa-Pàmies, R.; Hatzianestis, I.; Sanchez-Vidal, A.; Rousakis, G.; Velaoras, D.; Krokos, G.; Lykousis, V.

    2013-09-01

    Surface sediments collected from deep basins (1018-4087 m depth) of the eastern Mediterranean Sea (Ionian Sea, southern Aegean Sea and northwestern Levantine Sea) were analyzed for aliphatic and polycyclic aromatic hydrocarbons as tracers of natural and anthropogenic inputs. Concentrations of total aliphatic hydrocarbons, n-alkanes and the unresolved complex mixture (UCM) of aliphatic hydrocarbons varied significantly, ranging from 1.34 to 49.2 μg g-1, 145 to 4810 ng g-1 and 0.73 to 36.7 μg g-1, respectively, while concentrations of total polycyclic aromatic hydrocarbons (PAHs) ranged between 11.6 and 223 ng g-1. Molecular profiles of determined hydrocarbons reflect a mixed contribution from both natural and anthropogenic sources in deep-sea sediments of the eastern Mediterranean Sea, i.e., terrestrial plant waxes, degraded petroleum products, unburned fossil fuels and combustion of grass, wood and coal. Hydrocarbon mixtures display significant variability amongst sub-regions, reflecting differences in the relative importance of inputs from various sources and phase associations/transport pathways of individual hydrocarbons that impact on their overall distribution and fate. Hydrocarbon concentrations correlated significantly with the organic carbon content of sediments, indicating that the latter exerts an important control on their transport and ultimate accumulation in deep basins. Additionally, water masses' circulation characteristics also seem to influence the regional features and distribution patterns of hydrocarbons. Our findings highlight the role of deep basins/canyons as repositories of both natural and anthropogenic chemical species.

  18. Leading Meetings.

    ERIC Educational Resources Information Center

    Lindelow, John; Heynderickx, James

    Chapter 13 of a revised volume on school leadership, this chapter offers suggestions to help educators improve their performance in meetings, both as group leaders and as participants. Well-run meetings can rejuvenate an organization, leading to improved teamwork, communication, and morale. A poor meeting, on the other hand, can have a…

  19. Tetraethyl lead

    Integrated Risk Information System (IRIS)

    Tetraethyl lead ; CASRN 78 - 00 - 2 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinogenic Ef

  20. Mercury profiles in sediment from the marginal high of Arabian Sea: an indicator of increasing anthropogenic Hg input.

    PubMed

    Chakraborty, Parthasarathi; Vudamala, Krushna; Chennuri, Kartheek; Armoury, Kazip; Linsy, P; Ramteke, Darwin; Sebastian, Tyson; Jayachandran, Saranya; Naik, Chandan; Naik, Richita; Nath, B Nagender

    2016-05-01

    Total Hg distributions and its speciation were determined in two sediment cores collected from the western continental marginal high of India. Total Hg content in the sediment was found to gradually increase (by approximately two times) towards the surface in both the cores. It was found that Hg was preferentially bound to sulfide under anoxic condition. However, redox-mediated reactions in the upper part of the core influenced the total Hg content in the sediment cores. This study suggests that probable increase in authigenic and allogenic Hg deposition attributed to the increasing Hg concentration in the surface sediment in the study area.

  1. CULTURAL EUTROPHICATION OF SHALLOW COASTAL WATERS: COUPLING CHANGING ANTHROPOGENIC NUTRIENT INPUTS TO REGIONAL MANAGEMENT APPROACHES. (R825243)

    EPA Science Inventory

    The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

  2. Nitrogen Isotope Ratios of Juvenile Winter Flounder as an Indicator of Anthropogenic Nitrogen Inputs to Estuarine Systems

    EPA Science Inventory

    Nitrogen isotope ratios (15N) were measured in muscle tissue of juvenile winter flounder, Pseudopleuronectes americanus, collected from several estuarine systems (lagoons, river, bay) along the coast of Rhode Island, USA over a three-year period. Significant differences i...

  3. Lichen elemental composition distinguishes anthropogenic emissions from dust storm inputs and differs among species: Evidence from Xilinhot, Inner Mongolia, China

    PubMed Central

    Liu, Hua-Jie; Fang, Shi-Bo; Liu, Si-Wa; Zhao, Liang-Cheng; Guo, Xiu-Ping; Jiang, Yun-Jun; Hu, Jian-Sen; Liu, Xiao-Di; Xia, Yu; Wang, Yi-Dan; Wu, Qing-Feng

    2016-01-01

    To test the applicability of lichens in the biomonitoring of atmospheric elemental deposition in a typical steppe zone of Inner Mongolia, China, six foliose lichens (Physcia aipolia, PA; P. tribacia, PT; Xanthoria elegans, XE; X. mandschurica, XM; Xanthoparmelia camtschadalis, XPC; and Xp. tinctina, XPT) were sampled from the Xilin River Basin, Xilinhot, Inner Mongolia, China. Twenty-five elements (Al, Ba, Cd, Ce, Cr, Cs, Cu, Fe, K, La, Mn, Mo, Na, Ni, P, Pb, Sb, Sc, Sm, Tb, Th, Ti, Tl, V and Zn) in the lichens were analysed using inductively coupled plasma mass spectrometry (ICP-MS). The results show that Cd, Pb and Zn were mainly atmospheric in origin, whereas the other elements were predominantly of crustal origin. Compared with other studies, our data were higher in crustal element concentrations and lower in atmospheric element concentrations, matching with the frequent, severe dust storms and road traffic in the area. The elemental concentrations in lichens are both species- and element-specific, highlighting the importance of species selection for biomonitoring air pollution using lichens. We recommend PT, XE, XM and XPT for monitoring atmospheric deposition of crustal elements; XPC and XPT for Cd and Pb; PA for Cd and Zn; and PT for Cd. PMID:27698382

  4. Nitrogen Isotope Ratios of Juvenile Winter Flounder as an Indicator of Anthropogenic Nitrogen Inputs to Estuarine Systems

    EPA Science Inventory

    Nitrogen isotope ratios (15N) were measured in muscle tissue of juvenile winter flounder, Pseudopleuronectes americanus, collected from several estuarine systems (lagoons, river, bay) along the coast of Rhode Island, USA over a three-year period. Significant differences i...

  5. Influences of climate and land use on contemporary anthropogenic watershed phosphorus input and riverine export across the United States

    EPA Science Inventory

    Human beings have greatly accelerated nitrogen and phosphorus flows from land to aquatic ecosystems, often resulting in eutrophication, harmful algal blooms, and hypoxia in lakes and coastal waters. Although differences in nitrogen export from watersheds have been clearly linked ...

  6. Influences of climate and land use on contemporary anthropogenic watershed phosphorus input and riverine export across the United States

    EPA Science Inventory

    Human beings have greatly accelerated nitrogen and phosphorus flows from land to aquatic ecosystems, often resulting in eutrophication, harmful algal blooms, and hypoxia in lakes and coastal waters. Although differences in nitrogen export from watersheds have been clearly linked ...

  7. Lichen elemental composition distinguishes anthropogenic emissions from dust storm inputs and differs among species: Evidence from Xilinhot, Inner Mongolia, China

    NASA Astrophysics Data System (ADS)

    Liu, Hua-Jie; Fang, Shi-Bo; Liu, Si-Wa; Zhao, Liang-Cheng; Guo, Xiu-Ping; Jiang, Yun-Jun; Hu, Jian-Sen; Liu, Xiao-Di; Xia, Yu; Wang, Yi-Dan; Wu, Qing-Feng

    2016-10-01

    To test the applicability of lichens in the biomonitoring of atmospheric elemental deposition in a typical steppe zone of Inner Mongolia, China, six foliose lichens (Physcia aipolia, PA; P. tribacia, PT; Xanthoria elegans, XE; X. mandschurica, XM; Xanthoparmelia camtschadalis, XPC; and Xp. tinctina, XPT) were sampled from the Xilin River Basin, Xilinhot, Inner Mongolia, China. Twenty-five elements (Al, Ba, Cd, Ce, Cr, Cs, Cu, Fe, K, La, Mn, Mo, Na, Ni, P, Pb, Sb, Sc, Sm, Tb, Th, Ti, Tl, V and Zn) in the lichens were analysed using inductively coupled plasma mass spectrometry (ICP-MS). The results show that Cd, Pb and Zn were mainly atmospheric in origin, whereas the other elements were predominantly of crustal origin. Compared with other studies, our data were higher in crustal element concentrations and lower in atmospheric element concentrations, matching with the frequent, severe dust storms and road traffic in the area. The elemental concentrations in lichens are both species- and element-specific, highlighting the importance of species selection for biomonitoring air pollution using lichens. We recommend PT, XE, XM and XPT for monitoring atmospheric deposition of crustal elements; XPC and XPT for Cd and Pb; PA for Cd and Zn; and PT for Cd.

  8. Anthropogenic wetlands due to over-irrigation of desert areas; A challenging hydrogeological investigation with extensive geophysical input

    NASA Astrophysics Data System (ADS)

    Behroozmand, A. A.; Teatini, P.; Pedersen, J. B. B.; Auken, E.; Tosatto, O.; Christiansen, A. V.

    2015-12-01

    During the last century, many large irrigation projects have been initiated in arid lands worldwide. Despite a tremendous increase in food production, a common problem when characterizing these zones is land degradation in form of waterlogging. As results, large volumes of water are lost due to surplus irrigation in regions where water availability is extremely challenging for both population survival and economic development. The Nubariya depression, Western Desert (Egypt), is a clear example of this mechanism. Following the reclamation of desert lands for agricultural production, an artificial brackish and contaminated lake developed in the area in the late 1990s and presently extends for about 2.5 km2. Available data provide evidence of a simultaneous general deterioration of the groundwater system. With the main objectives of understanding the hydrological evolution of the area, characterizing the hydrogeological setting and developing scenarios for artificial aquifer remediation and recharge, an extensive hydrogeophysical investigation was carried out in this challenging environment using Magnetic Resonance Sounding (MRS, also called surface NMR) and ground-based Transient EM (TEM). The integrated interpretation of the geophysical surveys, properly calibrated with a number of boreholes, provides a clear hydrogeological picture of the upper 100 m sedimentary structure, in terms of both lithology and groundwater quality. The information is then used to set up a regional groundwater flow and a local density-dependent flow and transport numerical model to reproduce the past evolution of the aquifer system and develop a few scenarios for artificial aquifer recharge using the treated waters provided by a nearby waste-water treatment plant. The research outcomes point the hydrological challenges that emerge for an effective management of water resources in reclaimed desert areas and highlight the effectiveness of integrating advanced geophysical and modeling methodologies.

  9. Auto Draw from Excel Input Files

    NASA Technical Reports Server (NTRS)

    Strauss, Karl F.; Goullioud, Renaud; Cox, Brian; Grimes, James M.

    2011-01-01

    The design process often involves the use of Excel files during project development. To facilitate communications of the information in the Excel files, drawings are often generated. During the design process, the Excel files are updated often to reflect new input. The problem is that the drawings often lag the updates, often leading to confusion of the current state of the design. The use of this program allows visualization of complex data in a format that is more easily understandable than pages of numbers. Because the graphical output can be updated automatically, the manual labor of diagram drawing can be eliminated. The more frequent update of system diagrams can reduce confusion and reduce errors and is likely to uncover symmetric problems earlier in the design cycle, thus reducing rework and redesign.

  10. Potential effects of anthropogenic nitrogen on northern Indian Ocean nitrous oxide emissions

    NASA Astrophysics Data System (ADS)

    Zamora, L. M.; Suntharalingam, P.; Bange, H. W.; Bikkina, S.; Resplandy, L.; Sarin, M.; Schmidtko, S.; Seitzinger, S.; Singh, A.

    2016-02-01

    The North Indian Ocean (Arabian Sea + Bay of Bengal) accounts for 20-30% of the oceanic emissions of the greenhouse gas, nitrous oxide (N2O). The marine N2O cycle in the suboxic and anoxic waters of this region is very sensitive to relatively small shifts in ambient oxygen (O2); as O2 decreases, N2O production is progressively enhanced and subject to non-linear nitrogen (N) cycle dynamics. Thus, small, sustained changes in local O2 levels (e.g., < 5-10 mmol L-1) may result in detectable impacts on N2O emissions from the North Indian Ocean. Some recent data suggest that O2 may be declining in the already O2-impoverished Arabian Sea. While the reasons for these possible O2 declines are not fully understood, increasing anthropogenic N inputs from atmospheric and riverine sources likely contribute. In this study we bring together a combination of atmospheric deposition models, in situ measurements, and output from the NEWS riverine model to evaluate recent changes in nitrogen nutrient input to the Arabian Sea. We estimate that there has been a twofold increase in N loading from anthropogenic atmospheric deposition and river runoff to the North Indian Ocean during recent decades. To better understand how anthropogenic N increases might affect regional N2O emissions, we also present analysis of historical N2O and O2 measurements from the North Indian Ocean along with estimates of O2 and N2O fluxes from a regional marine biogeochemical model. We find that as in the Arabian Sea, Bay of Bengal O2 is also likely decreasing. However, due to the paucity of data, we are not yet able to estimate the role of anthropogenic N or how these changes might affect Bay of Bengal N2O emissions. While uncertainties are also high in the Arabian Sea, our preliminary results suggest that increases in atmospheric N deposition are enhancing regional N2O production.

  11. Archives of Atmospheric Lead Pollution

    NASA Astrophysics Data System (ADS)

    Weiss, Dominik; Shotyk, William; Kempf, Oliver

    Environmental archives such as peat bogs, sediments, corals, trees, polar ice, plant material from herbarium collections, and human tissue material have greatly helped to assess both ancient and recent atmospheric lead deposition and its sources on a regional and global scale. In Europe detectable atmospheric lead pollution began as early as 6000years ago due to enhanced soil dust and agricultural activities, as studies of peat bogs reveal. Increased lead emissions during ancient Greek and Roman times have been recorded and identified in many long-term archives such as lake sediments in Sweden, ice cores in Greenland, and peat bogs in Spain, Switzerland, the United Kingdom, and the Netherlands. For the period since the Industrial Revolution, other archives such as corals, trees, and herbarium collections provide similar chronologies of atmospheric lead pollution, with periods of enhanced lead deposition occurring at the turn of the century and since 1950. The main sources have been industry, including coal burning, ferrous and nonferrous smelting, and open waste incineration until c.1950 and leaded gasoline use since 1950. The greatest lead emissions to the atmosphere all over Europe occurred between 1950 and 1980 due to traffic exhaust. A marked drop in atmospheric lead fluxes found in most archives since the 1980s has been attributed to the phasing out of leaded gasoline. The isotope ratios of lead in the various archives show qualitatively similar temporal changes, for example, the immediate response to the introduction and phasing out of leaded gasoline. Isotope studies largely confirm source assessments based on lead emission inventories and allow the contributions of various anthropogenic sources to be calculated.

  12. Amounts, isotopic character, and ages of organic and inorganic carbon exported from rivers to ocean margins: 2. Assessment of natural and anthropogenic controls

    NASA Astrophysics Data System (ADS)

    Hossler, Katie; Bauer, James E.

    2013-04-01

    Riverine exports of carbon (C) and organic matter (OM) are regulated by a variety of natural and anthropogenic factors. Understanding the relationships between these various factors and C and OM exports can help to constrain global C budgets and allow assessment of current and future anthropogenic impacts on both riverine and global C cycles. We quantified the effects of multiple natural and anthropogenic controls on riverine export fluxes and compositions of particulate organic C, dissolved organic C, and dissolved inorganic C for a regional group of eight rivers in the northeastern U.S. Potential controls related to hydrogeomorphology and regional climate, soil order, soil texture, bedrock lithology, land use, and anthropogenic factors were analyzed individually, collectively, and at scales of both local and regional influence. Factors related to hydrogeomorphology and climate, followed in importance by land use and anthropogenic factors, exhibited the strongest impacts on riverine C exports and compositions, particularly at smaller localized scales. The effects of hydrogeomorphology and climate were primarily related to volumetric flow, which resulted in greater exports of terrestrial and total C. Principal anthropogenic factors included impacts of wastewater treatment plants (WWTPs) and river impoundments. The presence of WWTPs as well as anthropogenic use of carbonate-based materials (e.g., limestone) may have substantially increased riverine C exports, particularly fossil C exports, in the study region. The presence of nuclear power plants in the associated watersheds is also discussed because of the potential for anthropogenic 14C inputs and subsequent biasing of aquatic C studies utilizing natural abundance 14C.

  13. The characteristics of atmospheric trace elements input into East Antarctica as recorded in GV7 snow pit

    NASA Astrophysics Data System (ADS)

    Lee, Khanghyun; Han, Yeongcheol; Kang, Jung-Ho; Hong, Sang-Bum; Hwang, Heejin; Do Hur, Soon; Frezzotti, Massimo; Narcisi, Biancamaria

    2017-04-01

    A series of 60 snow samples covering 4.5 years from 2009 to 2013 were collected from the 3.0 m deep snow pit at GV7 site (70˚ 41' 17"S, 158˚ 51' 49"E, 1950 m asl), East Antarctica. These samples were analyzed for aluminum (Al), arsenic (As), manganese (Mn), lead (Pb), scandium (Sc), strontium (Sr), vanadium (V) and zinc (Zn) in order to characterize the relative contributions from natural and anthropogenic emissions to the fallout of these elements in East Antarctica. The mean concentrations of most of these elements are very low at the pg g-1 level, and differ by orders of magnitude from one element to another ranging from 0.10 pg g-1 for Sc to 232 pg g-1 for Al. The Al concentrations which represent atmospheric mineral dust input display high concentrations during summer seasons. The Al concentrations are highly correlated with Mn (r2=0.82), Sc (r2=0.83) and V (r2=0.76), and moderately correlated with As (r2=0.30), Pb (r2=0.41) and Zn (r2=0.15). This implies that atmospheric deposition of these elements in East Antarctica is closely related to atmospheric transport of crust dust. Crust enrichment factors (EFc) defined as concentration ratios between elements and Al in snow samples normalized with those in upper continental crust are relatively high for As (mean EFc=287), Pb (mean EFc=80) and Zn (mean EFc=104) representing these elements are largely enhanced by anthropogenic emission such as non-ferrous metal production and fossil fuel combustion. Meanwhile, EFc for Mn (mean EFc=6.8), Sc (mean EFc=11.7) and (mean EFc=4.3) are close to unit indicating these elements primarily originate from crust dust. However, temporal increases in EFc of Mn, Sc and V particularly during winter season imply long-range transport of anthropogenic emissions depending on seasonal air circulation patterns. Differently from other elements, Sr concentrations show high correlation with Na+ concentrations (r2=0.59) rather than those of Al (r2=0.0004). Combining with high EFc of Sr (mean

  14. Anthropogenic-driven rapid shifts in tree distribution lead to increased dominance of broadleaf species.

    PubMed

    Vayreda, Jordi; Martinez-Vilalta, Jordi; Gracia, Marc; Canadell, Josep G; Retana, Javier

    2016-12-01

    Over the past century, major shifts in the geographic distribution of tree species have occurred in response to changes in land use and climate. We analyse species distribution and abundance from about 33 000 forest inventory plots in Spain sampled twice over a period of 10-12 years. We show a dominance of range contraction (extinction), and demographic decline over range expansion (colonization), with seven of 11 species exhibiting extinction downhill of their distribution. Contrary to expectations, these dynamics are not always consistent with climate warming over the study period, but result from legacies in forest structure due to past land use change and fire occurrence. We find that these changes have led to the expansion of broadleaf species (i.e. family Fagaceae) over areas formerly dominated by conifer species (i.e. family Pinaceae), due to the greater capacity of the former to respond to most disturbances and their higher competitive ability. This recent and rapid transition from conifers to broadleaves has important implications in forest dynamics and ecosystem services they provide. The finding raises the question as to whether the increasing dominance of relatively drought-sensitive broadleaf species will diminish resilience of Mediterranean forests to very likely drier conditions in the future.

  15. Modeling Agassiz's Desert Tortoise Population Response to Anthropogenic Stressors

    EPA Science Inventory

    Mojave Desert tortoise (Gopherus agassizii) populations are exposed to a variety of anthropogenic threats, which vary in nature, severity, and frequency. Tortoise management in conservation areas can be compromised when the relative importance of these threats is not well underst...

  16. EVALUATION OF SIGNIFICANT ANTHROPOGENIC SOURCES OF RADIATIVELY IMPORTANT TRACE GASES

    EPA Science Inventory

    The report is an initial evaluation of significant anthropogenic sources of radiatively important trace gases. missions of greenhouse gases from human activities--including fossil fuel combustion, industrial/agricultural activities, and transportation--contribute to the increasin...

  17. Anthropogenic Eutrophication of Narragansett Bay: Evidence from Dated Sediment Cores

    EPA Science Inventory

    The organic matter preserved in estuarine sediments provides a number of useful indicators, or "proxies" that can be used to infer paleoenvironmental changes One type of paleoenvironmental change is anthropogenic eutrophication. The human activity largely responsible for increasi...

  18. The Role of Anthropogenic Aerosol in Atmospheric Circulation Changes

    NASA Astrophysics Data System (ADS)

    Wilcox, L.; Polvani, L. M.; Highwood, E.

    2015-12-01

    Changes in atmospheric circulation patterns play a dominant role in determining the impacts of a changing climate at the continental scale. Using CMIP5 single forcing experiments from an ensemble of models that provided anthropogenic aerosol only simulations to the archive, we quantify the influence of anthropogenic aerosol on several aspects of the atmospheric circulation, including tropical width, jet position, and jet strength. We show that there is a robust circulation response to anthropogenic aerosol in the mid twentieth century, induced by the large increases in emissions at that time. Although most anthropogenic aerosol is found in the Northern Hemisphere, a response is found in both the Northern and Southern hemispheres. We investigate the extent to which diversity in the temperature and circulation responses to aerosol are related to diversity in aerosol loading and radiative forcing.

  19. EVALUATION OF SIGNIFICANT ANTHROPOGENIC SOURCES OF RADIATIVELY IMPORTANT TRACE GASES

    EPA Science Inventory

    The report is an initial evaluation of significant anthropogenic sources of radiatively important trace gases. missions of greenhouse gases from human activities--including fossil fuel combustion, industrial/agricultural activities, and transportation--contribute to the increasin...

  20. Anthropogenic climate change has altered primary productivity in Lake Superior.

    PubMed

    O'Beirne, M D; Werne, J P; Hecky, R E; Johnson, T C; Katsev, S; Reavie, E D

    2017-06-09

    Anthropogenic climate change has the potential to alter many facets of Earth's freshwater resources, especially lacustrine ecosystems. The effects of anthropogenic changes in Lake Superior, which is Earth's largest freshwater lake by area, are not well documented (spatially or temporally) and predicted future states in response to climate change vary. Here we show that Lake Superior experienced a slow, steady increase in production throughout the Holocene using (paleo)productivity proxies in lacustrine sediments to reconstruct past changes in primary production. Furthermore, data from the last century indicate a rapid increase in primary production, which we attribute to increasing surface water temperatures and longer seasonal stratification related to longer ice-free periods in Lake Superior due to anthropogenic climate warming. These observations demonstrate that anthropogenic effects have become a prominent influence on one of Earth's largest, most pristine lacustrine ecosystems.

  1. Anthropogenic and climate-driven water depletion in Asia

    NASA Astrophysics Data System (ADS)

    Yi, Shuang; Sun, Wenke; Feng, Wei; Chen, Jianli

    2016-09-01

    Anthropogenic depletion of terrestrial water storage (TWS) can be alleviated in wet years and intensified in dry years, and this wet/dry pattern spanning seasons to years is termed climate variability. However, the anthropogenic and climate-driven changes have not been isolated in previous studies; thus, the estimated trend of changes in TWS is strongly dependent on the study period. Here we try to remove the influence of climate variability from the estimation of the anthropogenic contribution, which is an indicator of the environmental burden and important for TWS projections. Toward this end, we propose a linear relationship between the variation in water storage and precipitation. Factors related to the sensitivity of water storage to precipitation are given to correct for the climate variability, and the anthropogenic depletion of terrestrial water and groundwater in Asia is estimated to be -187 ± 38 Gt/yr and -100 ± 47 Gt/yr, respectively.

  2. GLOBAL INVENTORY OF VOLATILE COMPOUND EMISSIONS FROM ANTHROPOGENIC SOURCES

    EPA Science Inventory

    The report describes a global inventory anthropogenic volatile organic compound (VOC) emissions that includes a separate inventory for each of seven pollutant groups--paraffins, olefins, aromatics, formaldehyde, other aldehydes, other aromatics, and marginally reactive compounds....

  3. GLOBAL INVENTORY OF VOLATILE COMPOUND EMISSIONS FROM ANTHROPOGENIC SOURCES

    EPA Science Inventory

    The report describes a global inventory anthropogenic volatile organic compound (VOC) emissions that includes a separate inventory for each of seven pollutant groups--paraffins, olefins, aromatics, formaldehyde, other aldehydes, other aromatics, and marginally reactive compounds....

  4. Modeling Agassiz's Desert Tortoise Population Response to Anthropogenic Stressors

    EPA Science Inventory

    Mojave Desert tortoise (Gopherus agassizii) populations are exposed to a variety of anthropogenic threats, which vary in nature, severity, and frequency. Tortoise management in conservation areas can be compromised when the relative importance of these threats is not well underst...

  5. Anthropogenic climate change has altered primary productivity in Lake Superior

    NASA Astrophysics Data System (ADS)

    O'Beirne, M. D.; Werne, J. P.; Hecky, R. E.; Johnson, T. C.; Katsev, S.; Reavie, E. D.

    2017-06-01

    Anthropogenic climate change has the potential to alter many facets of Earth's freshwater resources, especially lacustrine ecosystems. The effects of anthropogenic changes in Lake Superior, which is Earth's largest freshwat