Science.gov

Sample records for acidic pit lakes

  1. Toxicity of acid mine pit lake water remediated with limestone and phosphorus

    SciTech Connect

    Neil, L.L.; McCullough, C.D.; Lund, M.A.; Evans, L.H.; Tsvetnenko, Y.

    2009-11-15

    Pit lakes are increasingly common worldwide and have potential to provide many benefits. However, lake water toxicity may require remediation before beneficial end uses can be realised. Three treatments to remediate AMD (pH similar to 4.8) pit lake water containing elevated concentrations of Al and Zn from Collie, Western Australia were tested in mesocosms. Treatments were: (a) limestone neutralisation (L), (b) phosphorus amendment (P), and c) combined limestone neutralisation and phosphorus amendment (L+P). Laboratory bioassays with Ceriodaphnia cf. dubia, Chlorella protothecoides and Tetrahymena thermophila assessed remediation. Limestone neutralisation increased pH and reduced heavy metal concentrations by 98% (Al) to 14% (Mg), removing toxicity to the three test species within 2 months. Phosphorus amendment removed toxicity after 6 months of treatment. However, phosphorus amendment to prior limestone neutralisation failed to reduce toxicity more than limestone neutralisation alone. Low concentrations of both phosphorus and nitrogen appear to limit phytoplankton population growth in all treatments.

  2. Assessment of factors limiting algal growth in acidic pit lakes--a case study from Western Australia, Australia.

    PubMed

    Kumar, R Naresh; McCullough, Clint D; Lund, Mark A; Larranaga, Santiago A

    2016-03-01

    Open-cut mining operations can form pit lakes on mine closure. These new water bodies typically have low nutrient concentrations and may have acidic and metal-contaminated waters from acid mine drainage (AMD) causing low algal biomass and algal biodiversity. A preliminary study was carried out on an acidic coal pit lake, Lake Kepwari, in Western Australia to determine which factors limited algal biomass. Water quality was monitored to obtain baseline data. pH ranged between 3.7 and 4.1, and solute concentrations were slightly elevated to levels of brackish water. Concentrations of N were highly relative to natural lakes, although concentrations of FRP (<0.01 mg/L) and C (total C 0.7-3.7 and DOC 0.7-3.5 mg/L) were very low, and as a result, algal growth was also extremely low. Microcosm experiment was conducted to test the hypothesis that nutrient enrichment will be able to stimulate algal growth regardless of water quality. Microcosms of Lake Kepwari water were amended with N, P and C nutrients with and without sediment. Nutrient amendments under microcosm conditions could not show any significant phytoplankton growth but was able to promote benthic algal growth. P amendments without sediment showed a statistically higher mean algal biomass concentration than controls or microcosms amended with phosphorus but with sediment did. Results indicated that algal biomass in acidic pit lake (Lake Kepwari) may be limited primarily by low nutrient concentrations (especially phosphorus) and not by low pH or elevated metal concentrations. Furthermore, sediment processes may also reduce the nutrient availability. PMID:26593729

  3. Assessment of factors limiting algal growth in acidic pit lakes--a case study from Western Australia, Australia.

    PubMed

    Kumar, R Naresh; McCullough, Clint D; Lund, Mark A; Larranaga, Santiago A

    2016-03-01

    Open-cut mining operations can form pit lakes on mine closure. These new water bodies typically have low nutrient concentrations and may have acidic and metal-contaminated waters from acid mine drainage (AMD) causing low algal biomass and algal biodiversity. A preliminary study was carried out on an acidic coal pit lake, Lake Kepwari, in Western Australia to determine which factors limited algal biomass. Water quality was monitored to obtain baseline data. pH ranged between 3.7 and 4.1, and solute concentrations were slightly elevated to levels of brackish water. Concentrations of N were highly relative to natural lakes, although concentrations of FRP (<0.01 mg/L) and C (total C 0.7-3.7 and DOC 0.7-3.5 mg/L) were very low, and as a result, algal growth was also extremely low. Microcosm experiment was conducted to test the hypothesis that nutrient enrichment will be able to stimulate algal growth regardless of water quality. Microcosms of Lake Kepwari water were amended with N, P and C nutrients with and without sediment. Nutrient amendments under microcosm conditions could not show any significant phytoplankton growth but was able to promote benthic algal growth. P amendments without sediment showed a statistically higher mean algal biomass concentration than controls or microcosms amended with phosphorus but with sediment did. Results indicated that algal biomass in acidic pit lake (Lake Kepwari) may be limited primarily by low nutrient concentrations (especially phosphorus) and not by low pH or elevated metal concentrations. Furthermore, sediment processes may also reduce the nutrient availability.

  4. A microbial arsenic cycle in sediments of an acidic mine impoundment: Herman Pit, Clear Lake, California

    USGS Publications Warehouse

    Blum, Jodi S.; McCann, Shelley; Bennett, S.; Miller, Laurence G.; Stolz, J. R.; Stoneburner, B.; Saltikov, C.; Oremland, Ronald S.

    2015-01-01

    The involvement of prokaryotes in the redox reactions of arsenic occurring between its +5 [arsenate; As(V)] and +3 [arsenite; As(III)] oxidation states has been well established. Most research to date has focused upon circum-neutral pH environments (e.g., freshwater or estuarine sediments) or arsenic-rich “extreme” environments like hot springs and soda lakes. In contrast, relatively little work has been conducted in acidic environments. With this in mind we conducted experiments with sediments taken from the Herman Pit, an acid mine drainage impoundment of a former mercury (cinnabar) mine. Due to the large adsorptive capacity of the abundant Fe(III)-rich minerals, we were unable to initially detect in solution either As(V) or As(III) added to the aqueous phase of live sediment slurries or autoclaved controls, although the former consumed added electron donors (i.e., lactate, acetate, hydrogen), while the latter did not. This prompted us to conduct further experiments with diluted slurries using the live materials from the first incubation as inoculum. In these experiments we observed reduction of As(V) to As(III) under anoxic conditions and reduction rates were enhanced by addition of electron donors. We also observed oxidation of As(III) to As(V) in oxic slurries as well as in anoxic slurries amended with nitrate. We noted an acid-tolerant trend for sediment slurries in the cases of As(III) oxidation (aerobic and anaerobic) as well as for anaerobic As(V) reduction. These observations indicate the presence of a viable microbial arsenic redox cycle in the sediments of this extreme environment, a result reinforced by the successful amplification of arsenic functional genes (aioA, and arrA) from these materials.

  5. Influence of bioturbation on the biogeochemistry of the sediment in the littoral zone of an acidic mine pit lake

    NASA Astrophysics Data System (ADS)

    Lagauzère, S.; Moreira, S.; Koschorreck, M.

    2010-10-01

    In the last decades, the mining exploitation of large areas in Lusatia (South-eastern Germany) but also in other mining areas worldwide has led to the formation of hundreds of pit lakes. Pyrite oxidation in the surrounding dumps makes many such lakes extremely acidic (pH < 3). The biogeochemical functioning of these lakes is mainly governed by cycling of iron. This represents a relevant ecological problem and intensive research has been conducted to understand the involved biogeochemical processes and develop bioremediation strategies. Despite some studies reporting the presence of living organisms (mostly bacteria, algae, and macro-invertebrates) under such acidic conditions, and their trophic interactions, their potential impact on the ecosystem functioning was poorly investigated. The present study aimed to assess the influence of chironomid larvae on oxygen dynamics and iron cycle in the sediment of acidic pit lakes. In the Mining Lake 111, used as a study case since 1996, Chironomus crassimanus (Insecta, Diptera) is the dominant benthic macro-invertebrate species and occurs at relatively high abundances in shallow water. A 16-day laboratory experiment using microcosms combined with high resolution measurements (DET gel probes and O2 microsensors) was carried out. The burrowing activity of C. crassimanus larvae induced a 3-fold increase of the oxygen consumption by sediment, and stimulated the mineralization of organic matter in the upper layers of the sediment. The iron cycle was also impacted (e.g. lower rates of reduction and oxidation, increase of iron-oxidizing bacteria abundance, stimulation of mineral formation) but with no significant effect on the iron flux at the sediment-water interface, and thus on the water acidity budget. This work provides the first assessment of bioturbation in an acidic mining lake and shows that its influence on biogeochemistry cannot be neglected.

  6. Influence of bioturbation on the biogeochemistry of littoral sediments of an acidic post-mining pit lake

    NASA Astrophysics Data System (ADS)

    Lagauzère, S.; Moreira, S.; Koschorreck, M.

    2011-02-01

    In the last decades, the mining exploitation of large areas in Lusatia (Eastern Germany) but also in other mining areas worldwide has led to the formation of hundreds of pit lakes. Pyrite oxidation in the surrounding dumps makes many such lakes extremely acidic (pH < 3). The biogeochemical functioning of these lakes is mainly governed by cycling of iron. This represents a relevant ecological problem and intensive research has been conducted to understand the involved biogeochemical processes and develop bioremediation strategies. Despite some studies reporting the presence of living organisms (mostly bacteria, algae, and macro-invertebrates) under such acidic conditions, and their trophic interactions, their potential impact on the ecosystem functioning was poorly investigated. The present study aimed to assess the influence of chironomid larvae on oxygen dynamics and iron cycle in the sediment of acidic pit lakes. In the Mining Lake 111, used as a study case since 1996, Chironomus crassimanus (Insecta, Diptera) is the dominant benthic macro-invertebrate species and occurs at relatively high abundances in shallow water. A 16-day laboratory experiment using microcosms combined with high resolution measurements (DET gel probes and O2 microsensors) was carried out. The burrowing activity of C. crassimanus larvae induced a 3-fold increase of the diffusive oxygen uptake by sediment, indicating a stimulation of the mineralization of organic matter in the upper layers of the sediment. The iron cycle was also impacted (e.g. lower rates of reduction and oxidation, increase of iron-oxidizing bacteria abundance, stimulation of mineral formation) but with no significant effect on the iron flux at the sediment-water interface, and thus on the water acidity budget. This work provides the first assessment of bioturbation in an acidic mining lake and shows that its influence on biogeochemistry cannot be neglected.

  7. CALL FOR ABSTRACTS - PIT LAKES 2004

    EPA Science Inventory

    This call for abstracts is for the 11/16-18/2004 Pit Lakes 2004 meeting held in Reno, NV. This conference will provide a forum for the exchange of scientific information on current domestic and international pit lake approaches, including pit lakes from arid and wet regions throu...

  8. INTERACTIVE PIT LAKES 2004 CONFERENCE

    EPA Science Inventory

    This CD and the workshop provide a pit lakes forum for the exchange of scientific information on current domestic and international approaches, including arid and wet regions throughout the world. These approaches include characterization, modeling/monitoring, and treatment and r...

  9. Microbial Diversity and Its Relationship to Physicochemical Characteristics of the Water in Two Extreme Acidic Pit Lakes from the Iberian Pyrite Belt (SW Spain)

    PubMed Central

    López-Pamo, Enrique; Gomariz, María; Amils, Ricardo; Aguilera, Ángeles

    2013-01-01

    The Iberian Pyrite Belt (IPB) hosts one of the world’s largest accumulations of acidic mine wastes and pit lakes. The mineralogical and textural characteristics of the IPB ores have favored the oxidation and dissolution of metallic sulfides, mainly pyrite, and the subsequent formation of acidic mining drainages. This work reports the physical properties, hydrogeochemical characteristics, and microbial diversity of two pit lakes located in the IPB. Both pit lakes are acidic and showed high concentrations of sulfate and dissolved metals. Concentrations of sulfate and heavy metals were higher in the Nuestra Señora del Carmen lake (NSC) by one order of magnitude than in the Concepción (CN) lake. The hydrochemical characteristics of NSC were typical of acid mine waters and can be compared with other acidic environments. When compared to other IPB acidic pit lakes, the superficial water of CN is more diluted than that of any of the others due, probably, to the strong influence of runoff water. Both pit lakes showed chemical and thermal stratification with well defined chemoclines. One particular characteristic of NSC is that it has developed a chemocline very close to the surface (2 m depth). Microbial community composition of the water column was analyzed by 16S and 18S rRNA gene cloning and sequencing. The microorganisms detected in NSC were characteristic of acid mine drainage (AMD), including iron oxidizing bacteria (Leptospirillum, Acidithiobacillus ferrooxidans) and facultative iron reducing bacteria and archaea (Acidithiobacillus ferrooxidans, Acidiphilium, Actinobacteria, Acidimicrobiales, Ferroplasma) detected in the bottom layer. Diversity in CN was higher than in NSC. Microorganisms known from AMD systems (Acidiphilium, Acidobacteria and Ferrovum) and microorganisms never reported from AMD systems were identified. Taking into consideration the hydrochemical characteristics of these pit lakes and the spatial distribution of the identified microorganisms, a

  10. Microbial Diversity and Its Relationship to Physicochemical Characteristics of the Water in Two Extreme Acidic Pit Lakes from the Iberian Pyrite Belt (SW Spain).

    PubMed

    Santofimia, Esther; González-Toril, Elena; López-Pamo, Enrique; Gomariz, María; Amils, Ricardo; Aguilera, Angeles

    2013-01-01

    The Iberian Pyrite Belt (IPB) hosts one of the world's largest accumulations of acidic mine wastes and pit lakes. The mineralogical and textural characteristics of the IPB ores have favored the oxidation and dissolution of metallic sulfides, mainly pyrite, and the subsequent formation of acidic mining drainages. This work reports the physical properties, hydrogeochemical characteristics, and microbial diversity of two pit lakes located in the IPB. Both pit lakes are acidic and showed high concentrations of sulfate and dissolved metals. Concentrations of sulfate and heavy metals were higher in the Nuestra Señora del Carmen lake (NSC) by one order of magnitude than in the Concepción (CN) lake. The hydrochemical characteristics of NSC were typical of acid mine waters and can be compared with other acidic environments. When compared to other IPB acidic pit lakes, the superficial water of CN is more diluted than that of any of the others due, probably, to the strong influence of runoff water. Both pit lakes showed chemical and thermal stratification with well defined chemoclines. One particular characteristic of NSC is that it has developed a chemocline very close to the surface (2 m depth). Microbial community composition of the water column was analyzed by 16S and 18S rRNA gene cloning and sequencing. The microorganisms detected in NSC were characteristic of acid mine drainage (AMD), including iron oxidizing bacteria (Leptospirillum, Acidithiobacillus ferrooxidans) and facultative iron reducing bacteria and archaea (Acidithiobacillus ferrooxidans, Acidiphilium, Actinobacteria, Acidimicrobiales, Ferroplasma) detected in the bottom layer. Diversity in CN was higher than in NSC. Microorganisms known from AMD systems (Acidiphilium, Acidobacteria and Ferrovum) and microorganisms never reported from AMD systems were identified. Taking into consideration the hydrochemical characteristics of these pit lakes and the spatial distribution of the identified microorganisms, a

  11. Geochemical behavior and dissolved species control in acid sand pit lakes, Sepetiba sedimentary basin, Rio de Janeiro, SE - Brazil

    NASA Astrophysics Data System (ADS)

    Marques, Eduardo D.; Sella, Sílvia M.; Bidone, Edison D.; Silva-Filho, Emmanoel V.

    2010-12-01

    This work shows the influence of pluvial waters on dissolved components and mineral equilibrium of four sand pit lakes, located in the Sepetiba sedimentary basin, SE Brazil. The sand mining activities promote sediment oxidation, lowering pH and increasing SO 4 contents. The relatively high acidity of these waters, similar to ore pit lakes environment and associated acid mine drainage, increases weathering rate, especially of silicate minerals, which produces high Al concentrations, the limiting factor for fish aquaculture. During the dry season, basic cations (Ca, Mg, K and Na), SiO 2 and Al show their higher values due to evapoconcentration and pH are buffered. In the beginning of the wet season, the dilution factor by rainwater increases SO 4 and decreases pH values. The aluminum monomeric forms (Al(OH) 2+ and Al(OH) 2+), the most toxic species for aquatic organisms, occur during the dry season, while AlSO 4+ species predominate during the wet season. Gibbsite, allophane, alunite and jurbanite are the reactive mineral phases indicated by PHREEQC modeling. During the dry season, hydroxialuminosilicate allophane is the main phase in equilibrium with the solution, while the sulphate salts alunite and jurbanite predominate in the rainy season due to the increasing of SO 4 values. Gibbsite is also in equilibrium with sand pit lakes waters, pointing out that hydrolysis reaction is a constant process in the system. Comparing to SiO 2, sulphate is the main Al retriever in the pit waters because the most samples (alunite and jurbanite) are in equilibrium with the solution in both seasons. This Al hydrochemical control allied to some precaution, like pH correction and fertilization of these waters, allows the conditions for fishpond culture. Equilibrium of the majority samples with kaolinite (Ca, Mg, Na diagrams) and primary minerals (K diagram) points to moderate weathering rate in sand pit sediments, which cannot be considered for the whole basin due to the anomalous

  12. Processes at the sediment water interface after addition of organic matter and lime to an acid mine pit lake mesocosm

    SciTech Connect

    Matthias Koschorreck; Elke Bozau; Rene Froemmichen; Walter Geller; Peter Herzsprung; Katrin Wendt-Potthoff

    2007-03-01

    A strategy to neutralize acidic pit lakes was tested in a field mesocosm of 4500 m{sup 3} volume in the Acidic Pit Mine Lake 111 in the Koyne-Plessa lignite mining district of Lusatia, Germany. Carbokalk, a byproduct from sugar production, and wheat straw was applied near to the sediment surface to stimulate in lake microbial alkalinity generation by sulfate and iron reduction. The biogeochemical processes at the sediment-water interface were studied over 3 years by geochemical monitoring and an in situ microprofiler. Substrate addition generated a reactive zone at the sediment surface where sulfate and iron reduction proceeded. Gross sulfate reduction reached values up to 10 mmol m{sup -2} d{sup -1}. The neutralization rates between 27 and 0 meq m{sup -2} d{sup -1} were considerably lower than in previous laboratory experiments. The precipitation of ferric iron minerals resulted in a growing acidic sediment layer on top of the neutral sediment. In this layer sulfate reduction was observed but iron sulfides could not precipitate. In the anoxic sediment H{sub 2}S was oxidized by ferric iron minerals. H{sub 2}S partly diffused to the water column where it was oxidized. As a result the net formation of iron sulfides decreased after 1 year although gross sulfate reduction rates continued to be high. The rate of iron reduction exceeded the sulfate reduction rate, which resulted in high fluxes of ferrous iron out of the sediment. 46 refs., 6 figs., 1 tab.

  13. Structure and function of the microbial community in an in situ reactor to treat an acidic mine pit lake.

    PubMed

    Koschorreck, Matthias; Geller, Walter; Neu, Thomas; Kleinsteuber, Sabine; Kunze, Tobias; Trosiener, Annegret; Wendt-Potthoff, Katrin

    2010-08-01

    Sulfate-reducing bioreactors are a promising option for the treatment of acid mine drainage. We studied the structure and function of a biofilm in a methanol-fed fixed-bed in-lake reactor for the treatment of an acidic pit lake by a combination of laboratory incubations, chemical and molecular analyses and confocal laser scanning microscopy to determine whether competition by different groups of microorganisms as well as the precipitation of minerals affect reactor performance negatively. The biofilm growing on the surface of a synthetic carrier material consisted of dense microbial colonies covered by iron-sulfide precipitates. The microorganisms continuously had to overgrow this mineral coating, resulting in a high biomass turnover. About one third of the added methanol was used by sulfate reduction, and the rest by competing reactions. Sulfate-reducing bacteria as well as methanogens and acetogens were involved in methanol consumption. Six different groups of Deltaproteobacteria, dominated by the genera Desulfomonile, Desulfobacterium and a phylotype related to Geobacter, Gram-positive sulfate reducers of the genus Desulfosporosinus, acetogenic Acetobacteria, different fermenting bacteria as well as methylotrophic methanogens were identified. The versatility of the microbial food web is probably an important factor stabilizing the biofilm function under fluctuating and partly oxidizing conditions in the reactor.

  14. Tale of two pit lakes: initial results of a three-year study of the Main Zone and Waterline pit lakes near Houston, British Columbia, Canada

    USGS Publications Warehouse

    Crusius, J.; Pieters, R.; Leung, A.; Whittle, P.; Pedersen, T.; Lawrence, G.; McNee, J.J.

    2003-01-01

    Pit lakes are becoming increasingly common in North America as well as in the rest of the world. They are created as openpit mines fill passively with ground water and surface inflows on cessation of mining activity. In many instances, the water quality in these pit lakes does not meet regulatory requirements due to a number of influences. The most important are the oxidation of sulfide minerals and the associated release of acid and metals and the flushing of soluble metals during pit filling. Examples of pit lakes with severe water-quality problems include the Berkeley Pit lake (Butte, MT) and the Liberty Pit lake (Nevada), whose waters are characterized by a pH near 3 and Cu concentrations as high as ~150 mg/L (Miller et al., 1996; Davis and Eary, 1997). The importance of the problem can be seen in the fact that some of these sites in the United States are Superfund sites.

  15. Enrichment of sulfate-reducing bacteria and resulting mineral formation in media mimicking pore water metal ion concentrations and pH conditions of acidic pit lakes.

    PubMed

    Meier, Jutta; Piva, Angela; Fortin, Danielle

    2012-01-01

    Acid mine drainage sites are extreme environments with high acidity and metal ion concentrations. Under anoxic conditions, microbial sulfate reduction may trigger the formation of secondary minerals as a result of H2S production and pH increase. This process was studied in batch experiments with enrichment cultures from acidic sediments of a pit lake using growth media set at different pH values and containing elevated concentrations of Fe²⁺ and Al³⁺. At initial pH values of 5 and 6, sulfate reduction occurred shortly after inoculation. Sulfate- reducing bacteria affiliated to the genus Desulfosporosinus predominated the microbial communities as shown by 16S rRNA gene analysis performed at the end of the incubation. At initial pH values of 3 and 4, sulfate reduction and cell growth occurred only after an extended lag phase, however, at a higher rate than in the less acidic assays. At the end of the growth phase, enrichments were dominated by Thermodesulfobium spp. suggesting that these sulfate reducers were better adapted to acidic conditions. Iron sulfides in the bulk phase were common in all assays, but specific aluminum precipitates formed in close association with cell surfaces and may function as a detoxification mechanism of dissolved Al species at low pH.

  16. Investigations on the "Extreme" Microbial Arsenic Cycle within the Sediments of an Acidic Impoundment of the Former Sulfur Bank Mercury Mine: Herman Pit, Clear Lake, California.

    NASA Astrophysics Data System (ADS)

    Blum, J. S.; Hoeft McCann, S. E.; Bennett, S.; Miller, L. G.; Stoneburner, B.; Saltikov, C.; Oremland, R. S.

    2014-12-01

    The involvement of prokaryotes in the redox reactions of arsenic occurring between this element's +5 [arsenate; As(V)] and + 3 [arsenite; As(III)] oxidation states has been well established. Most research has focused upon circum-neutral pH environments, such as freshwater lake and aquifer sediments, and extreme environments like hot springs and hypersaline soda lakes have also been well investigated. In contrast, little work has been conducted on acidic environments. The azure-hued, clear waters of the Herman Pit are acidic (pH 2-4), and overlie oxidized sediments that have a distinctive red/orange coloration indicative of the presence of ferrihydrites and other Fe(III) minerals. There is extensive ebullitive release of geothermal gases from the lake bottom in the form of numerous continuous-flow seeps which are composed primarily of mixtures of CO2, CH4, and H2S. We collected near-shore surface sediments with an Eckman grab, and stored the "soupy" material in filled mason jars kept at 4˚C. Initial experiments were conducted using 3:1 mixtures of lake water: sediment so as to generate dilute slurries which were amended with mM levels of electron acceptors (arsenate, nitrate, oxygen), electron donors (arsenite, acetate, lactate, hydrogen), and incubated under N2, air, or H2. Owing to the large adsorptive capacity of the Fe(III)-rich slurries, we were unable to detect As(V) or As(III) in the aqueous phase of either live or autoclaved controls, although the former consumed lactate, acetate, nitrate, or hydrogen, while the latter did not. This prompted us to conduct a series of further diluted slurry experiments using the live materials from the first as a 10 % addition to lakewater. In these experiments we observed reduction of As(V) to As(III) in anoxic slurries and that rates were enhanced by addition of electron donors (H2, acetate, or lactate). We also observed oxidation of As(III) to As(V) in oxic slurries and in anoxic slurries amended with nitrate. These

  17. Investigations on the "Extreme" Microbial Methane Cycle within the Sediments of an Acidic Impoundment of the Inactive Sulfur Bank Mercury Mine: Herman Pit, Clear Lake, California.

    NASA Astrophysics Data System (ADS)

    Oremland, R. S.; Baesman, S. M.; Miller, L. G.; Wei, J. H. C.; Welander, P. V.

    2014-12-01

    The inactive Sulfur Bank Mercury Mine is located in a volcanic region having geothermal flow and gas inputs into the Herman Pit impoundment. The acidic (pH 2 - 4) waters of the Herman Pit are permeated by hundreds of continuous flow gas seeps that contain CO2, H2S and CH4. We sampled one seep and found it to be composed of 95 % CO2 and 5 % CH4, in agreement with earlier measurements. Only a trace of ethane (10 - 20 ppm) was found and propane was below detection, resulting in a high CH4/C2H6 + C3H8 ratio of > 5,000, while the δ13CH4 and the δ13CO2 were respectively - 24 and - 11 per mil. Collectively, these results suggested a complex origin for the methane, being made up of a thermogenic component resulting from pyrolysis of buried organics, along with an active methanogenic portion. The relatively 12C-enriched value for the CO2 suggested a reworking of the ebullitive methane by methanotrophic bacteria. We found that dissolved methane in the collected water from 2-4 m depth was high (~ 400 µM), which would support methanotrophy in the lake's aerobic biomes. We therefore tested the ability of bottom sediments to consume methane by conducting aerobic incubations of slurried bottom sediments. Methane was removed from the headspace of live slurries, and subsequent additions of methane to the headspace over the course of 2-3 months resulted in faster removal rates suggesting a buildup of the population of methanotrophs. This activity could be transferred to an artificial medium originally devised for the cultivation of acidophilic iron oxidizing bacteria (Silverman and Lundgren, 1959; J. Bacteriol. 77: 642 - 647), suggesting the possibility of future cultivation of acidophilic methanotrophs. A successful extraction of some hopanoid compounds from the sediments was achieved, although the results were too preliminary at the time of this writing to identify any hopanoids specifically linked to methanotrophic bacteria. Further efforts to amplify functional genes for

  18. Comparative microbial ecology of the water column of an extreme acidic pit lake, Nuestra Señora del Carmen, and the Río Tinto basin (Iberian Pyrite Belt).

    PubMed

    González-Toril, Elena; Santofimia, Esther; López-Pamo, Enrique; García-Moyano, Antonio; Aguilera, Ángeles; Amils, Ricardo

    2014-12-01

    The Iberian Pyrite Belt, located in Southwestern Spain, represents one of the world's largest accumulations of mine wastes and acid mine drainages. This study reports the comparative microbial ecology of the water column of Nuestra Señora del Carmen acid pit lake with the extreme acidic Río Tinto basin. The canonical correspondence analysis identified members of the Leptospirillum, Acidiphilium, Metallibacterium, Acidithiobacillus, Ferrimicrobium and Acidisphaera genera as the most representative microorganisms of both ecosystems. The presence of archaeal members is scarce in both systems. Only sequences clustering with the Thermoplasmata have been retrieved in the bottom layer of Nuestra Señora del Carmen and one station of Río Tinto. Although the photosynthetically active radiation values measured in this lake upper layer were low, they were sufficient to activate photosynthesis in acidophilic microorganisms. All identified photosynthetic microorganisms in Nuestra Señora del Carmen (members of the Chlamydomonas, Zygnemopsis and Klebsormidium genera) are major members of the photosynthetic eukaryotic community characterized in Río Tinto basin. This study demonstrates a close relationship between the microbial diversity of Nuestra Señora del Carmen pit lake and the diversity detected in the Río Tinto basin, which underlain the influence of the shared mineral substrates in the microbial ecology of these ecosystems. PMID:26421738

  19. Fish assemblages in borrow-pit lakes of the Lower Mississippi River

    USGS Publications Warehouse

    Miranda, Leandro E.; Killgore, K. J.; Hoover, J.J.

    2013-01-01

    Borrow-pit lakes encompass about a third of the lentic water habitats (by area) in the active floodplain of the Lower Mississippi River, yet little is known about their fish assemblages. We investigated whether fish assemblages supported by borrow-pit lakes resembled those in oxbow lakes to help place the ecological relevance of borrow-pit lakes in context with that of natural floodplain lakes. In all, we collected 75 fish species, including 65 species in eight borrow-pit lakes, 52 species in four riverside oxbow lakes, and 44 species in eight landside oxbow lakes. Significant differences in several species richness metrics were evident between borrow-pit lakes and landside oxbow lakes but not between borrow-pit lakes and riverside oxbow lakes. All three lake types differed in fish assemblage composition. Borrow-pit lakes and riverside oxbow lakes tended to include a greater representation of fish species that require access to diverse environments, including lentic, lotic, and palustrine habitats; fish assemblages in landside oxbow lakes included a higher representation of lacustrine species. None of the fish species collected in borrow-pit lakes was federally listed as threatened or endangered, but several were listed as species of special concern by state governments in the region, suggesting that borrow-pit lakes provide habitat for sensitive riverine and wetland fish species. Differences in fish assemblages among borrow-pit lakes were linked to engineered morphologic features, suggesting that diversity in engineering can contribute to diversity in fish assemblages; however, more research is needed to match engineering designs with fish assemblage structures that best meet conservation needs.

  20. A method to predict evolving post-closure pit lake chemistry

    SciTech Connect

    Davis, A.; Fennemore, G.G.

    1998-12-31

    There are currently over 50 active open pit mines in Nevada, at least 30 of which may be inundated by ground water upon pit closure, forming lakes as deep as 200 m when the pumps dewatering the excavation are turned off. With the growing awareness of environmental issues related to mining, prediction of future pit-lake chemistry has become mandatory during permitting, to determine both potential ecological risk, and long-term impacts on downgradient groundwater quality. This paper outline a methodology that couples a groundwater model (MODFLOW) with the rate of solute leaching from pit wall rocks (derived from field experiments and the FND pyrite oxidation model), and the geochemical reactions occurring in the pit lake water column (using PHREEQC). The model would predict pit lake water quality (chemogenesis) from the juvenile infilling condition through a mature, hydrogeologically steady-state condition.

  1. Stimulation of sulfate-reducing bacteria in lake water from a former open-pit mine through addition of organic wastes

    SciTech Connect

    Castro, J.M.; Wielinga, B.W.; Gannon, J.E.; Moore, J.N.

    1999-03-01

    A method to improve water quality in a lake occupying a former open-pit mine was evaluated in a laboratory-scale study. Untreated pit lake water contained high levels of sulfate, iron, and arsenic and was mildly acidic ({approximately} pH 6). Varying amounts of two locally available organic waste products were added to pit water and maintained in microcosms under anoxic conditions. In selected microcosms, populations of sulfate-reducing bacteria increased with time; sulfide was generated by sulfate reduction; sulfate, iron, and arsenic concentrations approached zero; and pH approached neutrality. Best results were obtained with intermediate amounts of waste potato skin.

  2. Uranium activity ratio in water and fish from pit lakes in Kurday, Kazakhstan and Taboshar, Tajikistan.

    PubMed

    Strømman, G; Rosseland, B O; Skipperud, L; Burkitbaev, L M; Uralbekov, B; Heier, L S; Salbu, B

    2013-09-01

    Kurday in Kazhakstan and Taboshar in Tajikistan were U mining sites operated during the 1950s and 1960s as part of the USSR nuclear weapon program. Today, they represent sources of potential U contamination of the environment. Within both mining sites, open pits from which U ore was extracted have been filled with water due to ground water inflow and precipitation. These artificial pit lakes contain fish consumed occasionally by the local people, and wild and domestic animals are using the water for drinking purposes. To assess the potential impact from U in these pit lakes, field work was performed in 2006 in Kurday and 2006 and 2008 in Taboshar. Results show that the U concentration in the lake waters were relatively high, about 1 mg/L in Kurday Pit Lake and about 3 mg/L in Taboshar Pit Lake. The influence of U-bearing materials on the lakes and downstream waters were investigated by measuring the U concentration and the (234)U/(238)U activity ratios. In both Kurday and Taboshar, the ratios increased distinctively from about 1 at the pit lakes to >1.5 far downstream the lakes. The concentrations of (238)U in gill, liver, muscle and bones in fish from the pit lakes were much higher than in the reference fish. Peak concentration of U was seen in bones (13 mg/kg w.w.), kidney (9.1 mg/kg w.w.) and gills (8.9 mg/kg w.w.) from Cyprinus auratus caught in the Taboshar Pit Lake. Bioconcentration factors (BCF) calculated for organs from fish caught in the Taboshar Pit Lake, with the same tendency seen in the Kurday Pit Lake, showed that U accumulates most in bone (BCF = 4.8 L/kg w.w.), gills (BCF = 3.6 L/kg w.w.), kidney (BCF = 3.6 L/kg w.w.), and liver (BCF = 2.5 L/kg w.w.), while least was accumulated in the muscle (BCF = 0.12 L/kg w.w.).

  3. Groundwater and surface water interaction in flow-through gravel pit lakes.

    NASA Astrophysics Data System (ADS)

    Nella Mollema, Pauline; Antonellini, Marco

    2015-04-01

    Gravel pits are excavated in aquifers to fulfill the need for construction materials. Flow-through lakes form when the gravel pits are below the water table and fill with groundwater. In certain areas there are more than 60 of these lakes close together and their presence changes the drainage patterns and water- and hydrochemical budgets of a watershed. In flow-through gravel pit lakes, groundwater mixes with surface water and interacts with the atmosphere; outflow occurs only via groundwater. The lifespan of gravel pit lakes may be up to thousands of years as their depth to surface ratio is typically large and sedimentation rates are low. We have studied two gravel pit lake systems, a fluvial freshwater system in the Netherlands and a coastal brackish lake system in Italy. One Dutch gravel pit lake studied in detail is in part artificially replenished with Meuse River water for drinking water production that occurs downstream of the lake by water pumps. The Italian gravel pit lakes are fed by brackish groundwater that is a mix of freshwater from precipitation, Apennine Rivers and brackish (Holocene) Adriatic Sea water. Here, the drainage system of the low lying land enhances groundwater flow into the lake. Surface water evaporation is larger in temperate and Mediterranean climates than the actual evapotranspiration of pre-existing grassland and forests. The lakes, therefore, cause a loss of freshwater. The creation of water surfaces allows algae and other flora and fauna to develop. In general, water becomes gradually enriched in certain chemical constituents on its way through the hydrological cycle, especially as groundwater due to water-rock interactions. When groundwater ex-filtrates into gravel pit lakes, the natural flow of solutes towards the sea is interrupted. Hydrochemical analysis of ground- and surface waters, as well as chemical analysis of lake bottom sediments and stable H and O isotope data, show that gravel pit lake water is characterized (among

  4. Modeling the fate of elevated Cd, Cu and Zn in groundwater flowing from two sulfide mine pit lakes

    SciTech Connect

    Taufen, P.M.

    1996-10-01

    A study was made of observed reductions in the elevated levels of dissolved Cd, Cu and Zn over distances up to 1000m in groundwaters discharging from two acid mine pit lakes in southwestern Quebec, Canada. Groundwater flow from the lakes is chiefly in glacial till sediments on the bedrock. The shallow groundwaters were sampled for chemical analysis over two summers. Metal adsorption and mineral precipitation were assessed as a function of flow distance from the pit lakes. The tills were analyzed for their surface areas and content of organic C, Al{sub 2}O{sub 3}, MnO{sub 2}, and for total, oxide, carbonate and organic iron content. The tills were subjected to acid-base titrations to measure their adsorptive behavior towards Cd, Cu and Zn as a function of pH. Electrostatic adsorption models were found inapplicable to study results. However, distribution coefficients (K{sub d} values) for metal adsorption showed strong positive correlations with pH. Useful correlations with other till properties were absent.

  5. Hydrological investigation of a multi-stratified pit lake using radioactive and stable isotopes combined with hydrometric monitoring

    NASA Astrophysics Data System (ADS)

    Sánchez-España, Javier; Diez Ercilla, Marta; Pérez Cerdán, Fernando; Yusta, Iñaki; Boyce, Adrian J.

    2014-04-01

    The internal configuration and hydrological dynamics of meromictic pit lakes is often complex and needs to be studied by different tools including stable and radiogenic isotopes. This study combines a multi-isotopic approach (3Hw, δ2Hw, δ18Ow, δ34SSO4) with meteorological, hydrological and hydrochemical monitoring to deduce the flooding history and hydrological dynamics of a meromictic and deeply stratified pit lake (Cueva de la Mora mine, SW Spain). The mine system is complex and includes horizontal galleries, shafts and large rooms physically connected to the mine pit. Specific conductance and temperature profiles obtained in the pit lake draw a physical structure with four monimolimnetic sub-layers of increasing density with depth. This characteristic stratification with m-scale layers separated by sharp transitional zones is rather unusual in other pit lakes and in most natural lakes. Tritium abundance in the different layers indicates that the deep lake water entered the pit basin between 1971 and 1972 which is coincident with the dates of mine closure. The oxygen and deuterium isotope composition of the different layers describes a marked and stable stratification, with an increasing evaporative influence towards the lake surface and a minimal influence of groundwater flow on the structure and composition of the monimolimnion. This study reveals that the initial stages of flooding (via influx of metal- and sulfate-loaded mine drainage from underlying galleries at different depths) may be essential to imprint a layered physical structure to pit lakes which would be very difficult to explain merely by physical processes. After reaching its present water level and morphology, the monimolimnion of this pit lake seems to have remained essentially isolated and chemically unmodified during decades.

  6. Pit lake lime dosing: Assessment of the performance of the treatment based on a high-spatial resolution AUV survey

    NASA Astrophysics Data System (ADS)

    Delgado, Jordi; García-Morrondo, David; Cereijo-Arango, José Luis; Muñoz-Ibáñez, Andrea; Grande-García, Elisa; Rodríguez-Cedrún, Borja; Juncosa-Rivera, Ricardo

    2016-04-01

    The acidity of mine waters is typically corrected with passive (where possible) and/or active (i.e. chemical additions) systems. In the case of active treatments, lime dosing is a widespread technique due to the relatively ease of implementation and reduced operational costs. While neutralization of acidic waters is routinely performed in circulating water treatment facilities this is not so simple in open waters (e.g. pit lakes) because an efficient treatment requires the adequate distribution of the alkaline reagents throughout the volume of interest. To cope with this problem, a number of technical approaches have been proposed including active stirring (bubbling, etc.), surface spread diffusion, etc. In the early times of flooding of the Meirama mine, managers considered the necessity of lime dosing to correct the initially acidic mine waters. However, lake evolution proved that liming was not necessary and it was desirable to allow a reasonably unmanned evolution of the reclaimed system. In order to ensure that the lime dosing system is in good operative conditions in case of necessity, according to a prescribed time schedule to time mine managers put it in operation. That give us the opportunity to perform a large-scale "tracer" experiment useful to test the efficiency of wet lime dosing in a large water body. Dry lime, which is kept in a storage silo, is directly dosed over the channel of a small stream discharging in the lake. Therefore, stream water becomes saturated with lime and a pH of approximately 12.3. Stream water flows in cascade to the lake so that a certain potential and kinetic energy transfer is delivered to the lake. That promotes currents that enhance the re-distribution of the alkalinity load. In order to check for the distribution of alkaline water in the top body of the lake, an autonomous underwater vehicle (Yellow Spring Instruments Inc. EcoMapper AUV) was used. This device allows for the high- frequency simultaneous measurement of a

  7. Po-210 and Pb-210 in water and fish from Taboshar uranium mining Pit Lake, Tajikistan.

    PubMed

    Skipperud, L; Jørgensen, A G; Heier, L S; Salbu, B; Rosseland, B O

    2013-09-01

    Polonium-210 in water and (210)Pb and (210)Po in different fish organs from 3 different fish species in Taboshar Pit Lake (n = 13), located in the uranium mining area in Tajikistan, and in Kairakkum Reservoir (reference lake, n = 3), have been determined as part of a Joint project between Norway, Kazakhstan, Kyrgyzstan and Tajikistan. The average activity concentration of (210)Pb and (210)Po in liver, muscle and bone of Carassius auratus was higher than the concentration in similar tissues of C. carpio and Sander lucioperca from the reference site. The accumulation of (210)Po was higher than for (210)Pb, and the accumulation of (210)Po was highest in the liver of C. auratus (3673 ± 434 Bq kg(-1) ww). Although the average activity concentration of (210)Pb in liver and bones of C. auratus from Pit Lake were fairly similar, a huge variation in the liver activity concentrations (25-327 Bq kg(-1) ww) was found. The results confirm direct uptake of unsupported (210)Po into the liver, and that the distributions of (210)Po and (210)Pb in fish organs were different. The BCF (L/kg) for (210)Po in bone, liver and muscle clearly demonstrates high accumulation of (210)Po in C. auratus, especially in the liver. The average BCFs of liver, bone and muscle were >1.4 × 10(5), >2.5 × 10(4) and >1.4 × 10(4), respectively. All fish in the Pit Lake were found to be in the same trophic level, however, a linear correlation between log (210)Po in liver and δ(15)N could indicate biomagnification of (210)Po in liver of C. auratus. In regards to the recommended Annual Limit of Intake (ALI) for (210)Po, the concentration of (210)Po in muscle tissues of C. auratus is alarming, as there is a high probability for the local population at risk to exceed the recommended ALI through consumption of fish from Taboshar Pit Lake.

  8. Depth evolution of the Meirama pit lake, A Coruña, NW Spain

    NASA Astrophysics Data System (ADS)

    Delgado, Jordi; Juncosa-Rivera, Ricardo; Cereijo-Arango, José Luis; García-Morrondo, David; Muñoz-Ibáñez, Andrea; Grande-García, Elisa; Rodríguez-Cedrún, Borja

    2016-04-01

    The Meirama pit lake is a water mass in the process of controlled flooding that, by the end of December 2015, can be described as a steadily stratified meromictic system. The deepest portion of the lake (monimolimnion) is isolated regarding the annual mixing dynamics (December/January) of the upper water body (mixolimnion), for which the depth of mixing is restricted to a water column of 35-40 m thick. Due to the contrasting flooding history (access of groundwater at the beginning and mixed access of stream/groundwater (being dominant the stream water) the deepest portion of the lake is separated from the upper, non-mixed layer by a marked chemocline. Strictly speaking, the monimolimnion of a meromictic lake extends to the waters located beneath the mixed lake layer. In the case of the Meirama Lake the monimolimnion is internally stratified and made of two major water bodies. From hereafter the deep and upper monimolimnion will be identified as bottom and middle sections of the lake while the mixolimnion is referred to as the surface layer. The general characteristics and evolution of the Meirama Lake have been reported elsewhere. In this work we focus on a summary description of the chemical evolution of the monimolimnion of the lake based on data gathered between 2009 and 2015 from the still on-going monitoring survey. The chemical evolution of the monimolimnion of the lake differs significantly from that of the mixolimnion. In general, surface water is sensible to seasonal fluctuations due to weather conditions, rainfall and biogeochemical processes. The middle and bottom sections are not sensible, in general, to this effects and their evolution obeys to a number of internal processes. In the case of temperature we observe a nearly constant gradient increase (0.001 °C/day) in the middle and deep lake waters up to the beginning of 2012, where it remains constant. The rise in temperature is likely due to the heat provided by groundwater seepage whose temperature

  9. Selenium Bioaccumulation in Stocked Fish as an Indicator of Fishery Potential in Pit Lakes on Reclaimed Coal Mines in Alberta, Canada

    NASA Astrophysics Data System (ADS)

    Miller, L. L.; Rasmussen, J. B.; Palace, V. P.; Sterling, G.; Hontela, A.

    2013-07-01

    Pit lakes are a common reclamation strategy for open pit mines; however, there is a concern about their water quality and suitability as fish habitat because they are often contaminated by metals or metalloids. This study assessed the exposure of fish and invertebrates to selenium (Se) and other metals and metalloids in pit lakes formed by open pit coal mining in Tertiary (thermal coal) and in Cretaceous (metallurgical coal) bedrock. Juvenile hatchery rainbow trout, Oncorhynchus mykiss, and brook trout, Salvelinus fontinalis, were stocked into two thermal coal pit lakes (water Se < 2 μg/L, low water Se) and two metallurgical coal pit lakes (water Se > 15 μg/L, high water Se). Se accumulation in stocked fish and concentrations in invertebrates were characterized over a period of 2 years. In the metallurgical pits, invertebrates had higher Se concentrations and fish accumulated Se to higher levels (exceeding USEPA tissue Se guidelines) than biota in the thermal pits. Rainbow and brook trout accumulated similar concentrations of Se in their muscle and exhibited a similar relationship between whole-body and muscle Se concentrations. These results may be used by resource managers to assess compliance with whole-body tissue Se guidelines and to determine if pit lakes in coal mining areas pose a significant Se risk to wildlife or human health. The high Se exposure in metallurgical coal pits indicates that under the current mining and reclamation strategy, these lakes are not suitable for management as recreational "put and take" fisheries.

  10. Gravel pit lake ecosystems reduce nitrate and phosphate concentrations in the outflowing groundwater.

    PubMed

    Weilhartner, Andreas; Muellegger, Christian; Kainz, Martin; Mathieu, Francine; Hofmann, Thilo; Battin, Tom J

    2012-03-15

    Gravel excavation often bears conflicts with the use of drinking water as under-water-table mining can directly impact groundwater quality downstream of the open gravel pit lake due to exposure of the groundwater aquifer to the atmosphere and to human activities. To assess this potential impact of GPLs on groundwater, we assessed the mass balance for nitrate (NO(3)) and phosphate (PO(4)) and whole-ecosystem metabolism of five post-excavation GPLs in Austria. GPLs differed in both age and residence time of lake water. We found that GPLs significantly reduced the concentration of NO(3) and PO(4) as groundwater passes through the lake ecosystem, which in most cases acted as a net sink for these nutrients. Groundwater-derived nutrients enhanced both epilithic and pelagic net primary production in the GPLs, which ultimately leads to biomass accrual. Our data also suggest that this biomass accrual may induce, at least in part, clogging of the GPLs and their successive hydrodynamic isolation from the adjacent groundwater. Despite continuous biomass build-up and elevated concentrations of dissolved organic carbon (DOC) in the lake water compared to the inflowing groundwater, DOC export into the outflowing groundwater remained low. Our data suggest that GPLs could contribute to groundwater amelioration where agricultural land use increases nutrient concentrations in the groundwater given a proper management of these man-made ecosystems.

  11. PREVENTION OF ACID MINE DRAINAGE GENERATION FROM OPEN-PIT MINE HIGHWALLS

    EPA Science Inventory



    Exposed, open pit mine highwalls contribute significantly to the production of acid mine

    drainage (AMD) thus causing environmental concerns upon closure of an operating mine. Available information on the generation of AMD from open-pit mine highwalls is very limit...

  12. Positive and negative impacts of five Austrian gravel pit lakes on groundwater quality.

    PubMed

    Muellegger, Christian; Weilhartner, Andreas; Battin, Tom J; Hofmann, Thilo

    2013-01-15

    Groundwater-fed gravel pit lakes (GPLs) affect the biological, organic, and inorganic parameters of inflowing groundwater through combined effects of bank filtration at the inflow, reactions within the lake, and bank filtration at the outflow. GPLs result from wet dredging for sand and gravel and may conflict with groundwater protection programs by removing the protective soil cover and exposing groundwater to the atmosphere. We have investigated the impact on groundwater of five GPLs with different sizes, ages, and mean residence times, and all having low post-excavation anthropogenic usage. The results revealed highly active biological systems within the lake water, in which primary producers significantly reduced inflowing nitrate concentrations. Decalcification also occurred in lake water, reducing water hardness, which could be beneficial for waterworks in hard groundwater areas. Downgradient groundwater nitrate and calcium concentrations were found to be stable, with only minor seasonal variations. Biological degradation of organic material and organic micropollutants was also observed in the GPLs. For young GPLs adequate sediment deposits may not yet have formed and degradation processes at the outflow may consequently not yet be well established. However, our results showed that within 5 years from the cessation of excavation a protective sediment layer is established that is sufficient to prevent the export of dissolved organic carbon to downgradient groundwater. GPLs can improve groundwater quality in anthropogenically (e.g., pesticides and nitrate) or geologically (e.g., hardness) challenging situations. However, post-excavation usage of GPLs is often dominated by human activities such as recreational activities, water sports, or fish farming. These activities will affect lake and groundwater quality and the risks involved are difficult to predict and monitor and can lead to overall negative impacts on groundwater quality. PMID:23178886

  13. Quantifying, assessing and removing the extreme gas load from meromictic Guadiana pit lake, Southwest Spain.

    PubMed

    Boehrer, Bertram; Yusta, Iñaki; Magin, Katrin; Sanchez-España, Javier

    2016-09-01

    High gas charges in deep waters of lakes can represent a hazard to the lives of human beings and animals in the surrounding. As this danger was feared, we quantified the amount of dissolved gas in Guadiana pit lake (Las Herrerías, Huelva; southwest Spain) and documented the temporal evolution over a period of two years. Gas pressure due to dissolved gases, such as carbon dioxide, methane and nitrogen was measured. Based on these data, we assessed the risk and the associated danger of limnic eruptions from the lake and concluded that the present situation cannot be considered safe. By deploying a vertical pipe, the updraft of degassing water was tested and demonstrated: the pilot plant provided enough energy to drive a self-sustained flow. Such a system could be implemented to remove the extreme gas pressure from the deep water. Measurements of discharges could be extrapolated to indicate the size for an efficient plant for the gas removal. The construction of such a system would be technically and economically viable. A reintroduction of degassed water into the monimolimnion would be advisable. PMID:27151503

  14. ANCHOR HILL PIT LAKE IN SITU TREATMENT, GILT EDGE MINE SUPERFUND SITE, S. DAKOTA, USA - A RETROSPECTIVE

    EPA Science Inventory

    The EPA Region VII Superfund office and the EPA National Risk Management Research Laboratory (NRMRL) Mine Waste Technology Program (MWTP)have been conducting a field scale technology demonstration of an in situ treatment of the Anchor Hill Pit Lake at the Gilt Edge Mine Superfund...

  15. Modeling spatial and temporal variations in temperature and salinity during stratification and overturn in Dexter Pit Lake, Tuscarora, Nevada, USA

    USGS Publications Warehouse

    Balistrieri, L.S.; Tempel, R.N.; Stillings, L.L.; Shevenell, L.A.

    2006-01-01

    This paper examines the seasonal cycling of temperature and salinity in Dexter pit lake in arid northern Nevada, and describes an approach for modeling the physical processes that operate in such systems. The pit lake contains about 596,200 m3 of dilute, near neutral (pHs 6.7-9) water. Profiles of temperature, conductivity, and selected element concentrations were measured almost monthly during 1999 and 2000. In winter (January-March), the pit lake was covered with ice and bottom water was warmer (5.3 ??C) with higher total dissolved solids (0.298 g/L) than overlying water (3.96 ??C and 0.241 g/L), suggesting inflow of warm (11.7 ??C) groundwater with a higher conductivity than the lake (657 versus 126-383 ??S/cm). Seasonal surface inflow due to spring snowmelt resulted in lower conductivity in the surface water (232-247 ??S/cm) relative to deeper water (315-318 ??S/cm). The pit lake was thermally stratified from late spring through early fall, and the water column turned over in late November (2000) or early December (1999). The pit lake is a mixture of inflowing surface water and groundwater that has subsequently been evapoconcentrated in the arid environment. Linear relationships between conductivity and major and some minor (B, Li, Sr, and U) ions indicate conservative mixing for these elements. Similar changes in the elevations of the pit lake surface and nearby groundwater wells during the year suggest that the pit lake is a flow-through system. This observation and geochemical information were used to configure an one-dimensional hydrodynamics model (Dynamic Reservoir Simulation Model or DYRESM) that predicts seasonal changes in temperature and salinity based on the interplay of physical processes, including heating and cooling (solar insolation, long and short wave radiation, latent, and sensible heat), hydrologic flow (inflow and outflow by surface and ground water, pumping, evaporation, and precipitation), and transfers of momentum (wind stirring

  16. Amino acids in the Tagish Lake Meteorite

    NASA Technical Reports Server (NTRS)

    Kminek, G.; Botta, O.; Glavin, D. P.; Bada, J. L.

    2002-01-01

    High-performance liquid chromatography (HPLC) based amino acid analysis of a Tagish Lake meteorite sample recovered 3 months after the meteorite fell to Earth have revealed that the amino acid composition of Tagish Lake is strikingly different from that of the CM and CI carbonaceous chondrites. We found that the Tagish Lake meteorite contains only trace levels of amino acids (total abundance = 880 ppb), which is much lower than the total abundance of amino acids in the CI Orgueil (4100 ppb) and the CM Murchison (16 900 ppb). Because most of the same amino acids found in the Tagish Lake meteorite are also present in the Tagish Lake ice melt water, we conclude that the amino acids detected in the meteorite are terrestrial contamination. We found that the exposure of a sample of Murchison to cold water lead to a substantial reduction over a period of several weeks in the amount of amino acids that are not strongly bound to the meteorite matrix. However, strongly bound amino acids that are extracted by direct HCl hydrolysis are not affected by the leaching process. Thus even if there had been leaching of amino acids from our Tagish Lake meteorite sample during its 3 month residence in Tagish Lake ice and melt water, a Murchison type abundance of endogenous amino acids in the meteorite would have still been readily detectable. The low amino acid content of Tagish Lake indicates that this meteorite originated fiom a different type of parent body than the CM and CI chondrites. The parent body was apparently devoid of the reagents such as aldehyldes/ketones, HCN and ammonia needed for the effective abiotic synthesis of amino acids. Based on reflectance spectral measurements, Tagish Lake has been associated with P- or D-type asteroids. If the Tagish Lake meteorite was indeed derived fiom these types of parent bodies, our understanding of these primitive asteroids needs to be reevaluated with respect to their potential inventory of biologically important organic compounds.

  17. 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.

  18. Selenium bioaccumulation in stocked fish as an indicator of fishery potential in pit lakes on reclaimed coal mines in Alberta, Canada.

    PubMed

    Miller, L L; Rasmussen, J B; Palace, V P; Sterling, G; Hontela, A

    2013-07-01

    Pit lakes are a common reclamation strategy for open pit mines; however, there is a concern about their water quality and suitability as fish habitat because they are often contaminated by metals or metalloids. This study assessed the exposure of fish and invertebrates to selenium (Se) and other metals and metalloids in pit lakes formed by open pit coal mining in Tertiary (thermal coal) and in Cretaceous (metallurgical coal) bedrock. Juvenile hatchery rainbow trout, Oncorhynchus mykiss, and brook trout, Salvelinus fontinalis, were stocked into two thermal coal pit lakes (water Se < 2 μg/L, low water Se) and two metallurgical coal pit lakes (water Se > 15 μg/L, high water Se). Se accumulation in stocked fish and concentrations in invertebrates were characterized over a period of 2 years. In the metallurgical pits, invertebrates had higher Se concentrations and fish accumulated Se to higher levels (exceeding USEPA tissue Se guidelines) than biota in the thermal pits. Rainbow and brook trout accumulated similar concentrations of Se in their muscle and exhibited a similar relationship between whole-body and muscle Se concentrations. These results may be used by resource managers to assess compliance with whole-body tissue Se guidelines and to determine if pit lakes in coal mining areas pose a significant Se risk to wildlife or human health. The high Se exposure in metallurgical coal pits indicates that under the current mining and reclamation strategy, these lakes are not suitable for management as recreational "put and take" fisheries. PMID:23665755

  19. Characterization of physical mass transport through oil sands fluid fine tailings in an end pit lake: a multi-tracer study

    NASA Astrophysics Data System (ADS)

    Dompierre, Kathryn A.; Barbour, S. Lee

    2016-06-01

    Soft tailings pose substantial challenges for mine reclamation due to their high void ratios and low shear strengths, particularly for conventional terrestrial reclamation practices. Oil sands mine operators have proposed the development of end pit lakes to contain the soft tailings, called fluid fine tailings (FFT), generated when bitumen is removed from oil sands ore. End pit lakes would be constructed within mined-out pits with FFT placed below the lake water. However, the feasibility of isolating the underlying FFT has yet to be fully evaluated. Chemical constituents of interest may move from the FFT into the lake water via two key processes: (1) advective-diffusive mass transport with upward pore water flow caused by settling of the FFT; and (2) mixing created by wind events or unstable density profiles through the lake water and upper portion of the FFT. In 2013 and 2014, temperature and stable isotopes of water profiles were measured through the FFT and lake water in the first end pit lake developed by Syncrude Canada Ltd. Numerical modelling was undertaken to simulate these profiles to identify the key mechanisms controlling conservative mass transport in the FFT. Shallow mixing of the upper 1.1 m of FFT with lake water was required to explain the observed temperature and isotopic profiles. Following mixing, the re-establishment of both the temperature and isotope profiles required an upward advective flux of approximately 1.5 m/year, consistent with average FFT settling rates measured at the study site. These findings provide important insight on the ability to sequester soft tailings in an end pit lake, and offer a foundation for future research on the development of end pit lakes as an oil sands reclamation strategy.

  20. Characterization of physical mass transport through oil sands fluid fine tailings in an end pit lake: a multi-tracer study.

    PubMed

    Dompierre, Kathryn A; Barbour, S Lee

    2016-06-01

    Soft tailings pose substantial challenges for mine reclamation due to their high void ratios and low shear strengths, particularly for conventional terrestrial reclamation practices. Oil sands mine operators have proposed the development of end pit lakes to contain the soft tailings, called fluid fine tailings (FFT), generated when bitumen is removed from oil sands ore. End pit lakes would be constructed within mined-out pits with FFT placed below the lake water. However, the feasibility of isolating the underlying FFT has yet to be fully evaluated. Chemical constituents of interest may move from the FFT into the lake water via two key processes: (1) advective-diffusive mass transport with upward pore water flow caused by settling of the FFT; and (2) mixing created by wind events or unstable density profiles through the lake water and upper portion of the FFT. In 2013 and 2014, temperature and stable isotopes of water profiles were measured through the FFT and lake water in the first end pit lake developed by Syncrude Canada Ltd. Numerical modelling was undertaken to simulate these profiles to identify the key mechanisms controlling conservative mass transport in the FFT. Shallow mixing of the upper 1.1 m of FFT with lake water was required to explain the observed temperature and isotopic profiles. Following mixing, the re-establishment of both the temperature and isotope profiles required an upward advective flux of approximately 1.5 m/year, consistent with average FFT settling rates measured at the study site. These findings provide important insight on the ability to sequester soft tailings in an end pit lake, and offer a foundation for future research on the development of end pit lakes as an oil sands reclamation strategy.

  1. Characterization of physical mass transport through oil sands fluid fine tailings in an end pit lake: a multi-tracer study.

    PubMed

    Dompierre, Kathryn A; Barbour, S Lee

    2016-06-01

    Soft tailings pose substantial challenges for mine reclamation due to their high void ratios and low shear strengths, particularly for conventional terrestrial reclamation practices. Oil sands mine operators have proposed the development of end pit lakes to contain the soft tailings, called fluid fine tailings (FFT), generated when bitumen is removed from oil sands ore. End pit lakes would be constructed within mined-out pits with FFT placed below the lake water. However, the feasibility of isolating the underlying FFT has yet to be fully evaluated. Chemical constituents of interest may move from the FFT into the lake water via two key processes: (1) advective-diffusive mass transport with upward pore water flow caused by settling of the FFT; and (2) mixing created by wind events or unstable density profiles through the lake water and upper portion of the FFT. In 2013 and 2014, temperature and stable isotopes of water profiles were measured through the FFT and lake water in the first end pit lake developed by Syncrude Canada Ltd. Numerical modelling was undertaken to simulate these profiles to identify the key mechanisms controlling conservative mass transport in the FFT. Shallow mixing of the upper 1.1 m of FFT with lake water was required to explain the observed temperature and isotopic profiles. Following mixing, the re-establishment of both the temperature and isotope profiles required an upward advective flux of approximately 1.5 m/year, consistent with average FFT settling rates measured at the study site. These findings provide important insight on the ability to sequester soft tailings in an end pit lake, and offer a foundation for future research on the development of end pit lakes as an oil sands reclamation strategy. PMID:27061245

  2. Acid deposition: Processes of Lake Acidification

    SciTech Connect

    Not Available

    1984-01-01

    The Panel on Processes of Lake Acidification was assembled by the National Research Council at the request of the Environmental Protection Agency. The panel was charged with discussing the processes that control the rate of acidification of streams and lakes and to suggest how EPA's research program might approach addressing current deficiencies in knowledge. The panel defined the acidification of lakes and streams as a decrease in alkalinity over time. Soil acidification is the decrease in the percent base saturation over time. The panel concurred that in forested watersheds that are underlain by granitic or other highly siliceous bedrock with acidic forest soils not receiving appreciable acid deposition, most lakes and streams have bicarbonate as the dominant anion and pH levels above 5.5. Generally, lakes and streams in similar habitats but in areas receiving appreciable acid deposition have sulfate as the dominant anion.

  3. Acid Raindrops Keep Fallin' in My Lake.

    ERIC Educational Resources Information Center

    Journal of Chemical Education, 2003

    2003-01-01

    Demonstrates acid rain falling into lakes using vinegar and explores the effects on different types of solids such as chalk, sand, and lime. Includes instructor information and student worksheets. (YDS)

  4. Initial geochemical characteristics of fluid fine tailings in an oil sands end pit lake.

    PubMed

    Dompierre, Kathryn A; Lindsay, Matthew B J; Cruz-Hernández, Pablo; Halferdahl, Geoffrey M

    2016-06-15

    Geochemical characteristics of fluid fine tailings (FFT) were examined in Base Mine Lake (BML), which is the first full-scale demonstration oil sands end pit lake (EPL) in northern Alberta, Canada. Approximately 186Mm(3) of FFT was deposited between 1994 and 2012, before BML was established on December 31, 2012. Bulk FFT samples (n=588) were collected in July and August 2013 at various depths at 15 sampling sites. Temperature, solid content, electrical conductivity (EC), pH, Eh and alkalinity were measured for all samples. Detailed geochemical analyses were performed on a subset of samples (n=284). Pore-water pH decreased with depth by approximately 0.5 within the upper 10m of the FFT. Major pore-water constituents included Na (880±96mgL(-1)) and Cl (560±95mgL(-1)); Ca (19±4.1mgL(-1)), Mg (11±2.0mgL(-1)), K (16±2.3mgL(-1)) and NH3 (9.9±4.7mgL(-1)) were consistently observed. Iron and Mn concentrations were low within FFT pore water, whereas SO4 concentrations decreased sharply across the FFT-water interface. Geochemical modeling indicated that FeS(s) precipitation was favoured under SO4-reducing conditions. Pore water was also under-saturated with respect to gypsum [CaSO4·2H2O], and near saturation with respect to calcite [CaCO3], dolomite [CaMg(CO3)2] and siderite [FeCO3]. X-ray diffraction (XRD) suggested that carbonate-mineral dissolution largely depleted calcite and dolomite. X-ray absorption near edge structure (XANES) spectroscopy revealed the presence of FeS(s), pyrite [FeS2], and siderite. Carbonate-mineral dissolution and secondary mineral precipitation have likely contributed to FFT dewatering and settlement. However, the long-term importance of these processes within EPLs remains unknown. These results provide a reference for assessing the long-term geochemical evolution of oil sands EPLs, and offer insight into the chemistry of pore water released from FFT to the overlying water cover. PMID:26974568

  5. Hyperspectral analysis for qualitative and quantitative features related to acid mine drainage at a remediated open-pit mine

    NASA Astrophysics Data System (ADS)

    Davies, G.; Calvin, W. M.

    2015-12-01

    The exposure of pyrite to oxygen and water in mine waste environments is known to generate acidity and the accumulation of secondary iron minerals. Sulfates and secondary iron minerals associated with acid mine drainage (AMD) exhibit diverse spectral properties in the ultraviolet, visible and near-infrared regions of the electromagnetic spectrum. The use of hyperspectral imagery for identification of AMD mineralogy and contamination has been well studied. Fewer studies have examined the impacts of hydrologic variations on mapping AMD or the unique spectral signatures of mine waters. Open-pit mine lakes are an additional environmental hazard which have not been widely studied using imaging spectroscopy. A better understanding of AMD variation related to climate fluctuations and the spectral signatures of contaminated surface waters will aid future assessments of environmental contamination. This study examined the ability of multi-season airborne hyperspectral data to identify the geochemical evolution of substances and contaminant patterns at the Leviathan Mine Superfund site. The mine is located 24 miles southeast of Lake Tahoe and contains remnant tailings piles and several AMD collection ponds. The objectives were to 1) distinguish temporal changes in mineralogy at a the remediated open-pit sulfur mine, 2) identify the absorption features of mine affected waters, and 3) quantitatively link water spectra to known dissolved iron concentrations. Images from NASA's AVIRIS instrument were collected in the spring, summer, and fall seasons for two consecutive years at Leviathan (HyspIRI campaign). Images had a spatial resolution of 15 meters at nadir. Ground-based surveys using the ASD FieldSpecPro spectrometer and laboratory spectral and chemical analysis complemented the remote sensing data. Temporal changes in surface mineralogy were difficult to distinguish. However, seasonal changes in pond water quality were identified. Dissolved ferric iron and chlorophyll

  6. MINE WASTE TECHNOLOGY PROGRAM PREVENTION OF ACID MINE DRAINAGE GENERATION FROM OPEN-PIT HIGHWALLS

    EPA Science Inventory

    This document summarizes the results of Mine Waste Technology Program Activity III, Project 26, Prevention of Acid Mine Drainage Generation from Open-Pit Highwalls. The intent of this project was to obtain performance data on the ability of four technologies to prevent the gener...

  7. Acid Pit Stabilization Project (Volume 1 - Cold Testing) and (Volume 2 - Hot Testing)

    SciTech Connect

    G. G. Loomis; A. P. Zdinak; M. A. Ewanic; J. J. Jessmore

    1998-01-01

    During the summer and fall of Fiscal Year 1997, a Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) Treatability Study was performed at the Idaho National Engineering and Environmental Laboratory. The study involved subsurface stabilization of a mixed waste contaminated soil site called the Acid Pit. This study represents the culmination of a successful technology development effort that spanned Fiscal Years 1994-1996. Research and development of the in situ grout stabilization technique was conducted. Hardware and implementation techniques are currently documented in a patent pending with the United States Patent and Trademark Office. The stabilization technique involved using jet grouting of an innovative grouting material to form a monolith out of the contamination zone. The monolith simultaneously provides a barrier to further contaminant migration and closes voids in the soil structure against further subsidence. This is accomplished by chemical incorporation of contaminants into less soluble species and achieving a general reduction in hydraulic conductivity within the monolith. The grout used for this study was TECT-HG, a relatively dense iron oxide-based cementitious grout. The treatability study involved cold testing followed by in situ stabilization of the Acid Pit. Volume 1 of this report discusses cold testing, performed as part of a ''Management Readiness Assessment'' in preparation for going hot. Volume 2 discusses the results of the hot Acid Pit Stabilization phase of this project. Drilling equipment was specifically rigged to reduce the spread of contamination, and all grouting was performed under a concrete block containing void space to absorb any grout returns. Data evaluation included examination of implementability of the grouting process and an evaluation of the contaminant spread during grouting. Following curing of the stabilized pit, cores were obtained and evaluated for toxicity characteristic leach ing

  8. Determination of polyfluoroalkyl phosphoric acid diesters, perfluoroalkyl phosphonic acids, perfluoroalkyl phosphinic acids, perfluoroalkyl carboxylic acids, and perfluoroalkane sulfonic acids in lake trout from the Great Lakes region.

    PubMed

    Guo, Rui; Reiner, Eric J; Bhavsar, Satyendra P; Helm, Paul A; Mabury, Scott A; Braekevelt, Eric; Tittlemier, Sheryl A

    2012-11-01

    A comprehensive method to extract perfluoroalkyl carboxylic acids, perfluoroalkane sulfonic acids, perfluoroalkyl phosphonic acids, perfluoroalkyl phosphinic acids, and polyfluoroalkyl phosphoric acid diesters simultaneously from fish samples has been developed. The recoveries of target compounds ranged from 78 % to 121 %. The new method was used to analyze lake trout (Salvelinus namaycush) from the Great Lakes region. The results showed that the total perfluoroalkane sulfonate concentrations ranged from 0.1 to 145 ng/g (wet weight) with perfluorooctane sulfonate (PFOS) as the dominant contaminant. Concentrations in fish between lakes were in the order of Lakes Ontario ≈ Erie > Huron > Superior ≈ Nipigon. The total perfluoroalkyl carboxylic acid concentrations ranged from 0.2 to 18.2 ng/g wet weight. The aggregate mean perfluorooctanoic acid (PFOA) concentration in fish across all lakes was 0.045 ± 0.023 ng/g. Mean concentrations of PFOA were not significantly different (p > 0.1) among the five lakes. Perfluoroalkyl phosphinic acids were detected in lake trout from Lake Ontario, Lake Erie, and Lake Huron with concentration ranging from non-detect (ND) to 0.032 ng/g. Polyfluoroalkyl phosphoric acid diesters were detected only in lake trout from Lake Huron, at levels similar to perfluorooctanoic acid.

  9. WORKSHOP ON THE CHARACTERIZATION, MODELING, REMEDIATION AND MONITORING OF MINING-IMPACTED PIT LAKES, SANDS RGENCY CASINO HOTEL, DOWNTOWN RENO, NV. APRIL 4-6, 2000 (PROGRAM FLYER)

    EPA Science Inventory

    The purpose of this workshop is to provide a forum for the exchange of scientific infomation on current approaches for assessing the characterization, monitoring, treatment and/or remediation of impacts on aquatic ecosystems including pit lakes from mining-related contamination i...

  10. Spatial characterization of acid rain stress in Canadian Shield lakes

    NASA Technical Reports Server (NTRS)

    Tanis, Fred J.

    1986-01-01

    The acidification of lake waters from airborne pollutants is of continental proportions both in North America and Europe. A major concern of the acid rain problem is the cumulative ecosystem damage to lakes and forest. The number of lakes affected in northeastern United States and on the Canadian Shield is though to be enormous. The principle objective is to examine how seasonal changes in lake water transparency are related to annual acidic load. Further, the relationship between variations in lake acidification and ecophysical units is being examined. Finally, the utility of Thematic Mapper (TM) based observations to measure seasonal changes in the optical transparency in acid lakes is being investigated.

  11. Distribution of haloacetic acids in the water columns of the Laurentian Great Lakes and Lake Malawi.

    PubMed

    Scott, Brian F; Spencer, Christine; Marvin, Christopher H; MacTavish, David C; Muir, Derek C G

    2002-05-01

    Haloacetic acids (HAAs) are persistent and mildly phytotoxic compounds that have been detected in many aquatic environments, including the waters of the Great Lakes. Sources of HAAs, especially of trifluoroacetic acid (TFA), are not well understood. In this study we assessed the influence of urbanization on the concentrations and profiles of HAAs in the Laurentian Great Lakes and in Lake Malawi, an African Great Lake. Vertical depth profiles for these compounds were taken for each of the Great Lakes with additional profiles taken 2 years later for Lakes Erie and Ontario. The results showed that while TFA was relatively constant throughout the water column, the chloroacetic acids (CAAs) varied with depth. There was a trend of increasing TFA proceeding from Lake Superior to Lake Ontario (18-150 ng/L). Total CAA concentrations were relatively constant throughout the lakes (approximately 500 ng/L) with dichloroacetic acid being the most abundant. No bromoacetic acids were detected. In the Detroit River, a connecting channel between Lakes Huron and Erie, the TFA values were similar to those in Lake Huron, but the CAAs levels were higher than in the upstream lakes and dependent on location, indicating inputs from urban areas along the river. These results were compared to those from Lake Malawi, which has a high population density within the watershed but no heavy industry. CAAs were nondetectable, and TFA concentrations were just at the detection limit (1 ng/L). Total HAA in the water column of Lakes Superior and Huron was compared to annual precipitation inputs at a site situated near both lakes. For Lake Huron, precipitation was a minor contributor to the total HAA inventory of the lake, but for Lake Superior precipitation could be the major contributor to the mass of HAA in this lake. Generally, high HAA levels paralleled the degree of industrial activity in the adjacent waters.

  12. Spatial characterization of acid rain stress in Canadian Shield lakes

    NASA Technical Reports Server (NTRS)

    Tanis, Fred J.

    1986-01-01

    A major concern of the acid rain problem is the cumulative ecosystem damage to lakes and forests. The number of lakes affected in northeastern United States and on the Canadian Shield is thought to be enormous. Seasonal changes in lake transparency are examined relative to annual acidic load. The relationship between variations in lake acidification and ecophysical units is being examined. Finally, the utility of Thematic Mapper (TM) based observations is being used to measure seasonal changes in the optical transparency in acid lakes.

  13. The effects of phosphorus additions on the sedimentation of contaminants in a uranium mine pit-lake.

    PubMed

    Dessouki, Tarik C E; Hudson, Jeff J; Neal, Brian R; Bogard, Matthew J

    2005-08-01

    We investigated the usefulness of phytoplankton for the removal of surface water contaminants. Nine large mesocosms (92.2m(3)) were suspended in the flooded DJX uranium pit at Cluff Lake (Saskatchewan, Canada), and filled with highly contaminated mine water. Each mesocosm was fertilized with a different amount of phosphorus throughout the 35 day experiment to stimulate phytoplankton growth, and to create a range in phosphorus load (g) to examine how contaminants may be affected by different nutrient regimes. Algal growth was rapid in fertilized mesocosms (as demonstrated by chlorophyll a profiles). As phosphorus loads increased there were significant declines (p<0.05) in the surface water concentrations of As, Co, Cu, Mn, Ni, and Zn. This decline was near significant for uranium (p=0.065). The surface water concentrations of Ra-226, Mo, and Se showed no relationship to phosphorus load. Contaminant concentrations in sediment traps suspended at the bottom of each mesocosm generally showed the opposite trend to that observed in the surface water, with most contaminants (As, Co, Cu, Mn, Ni, Ra-226, U, and Zn) exhibiting a significant positive relationship (p<0.05) with phosphorus load. Selenium and Mo did not respond to nutrient treatments. Our results suggest that phytoremediation has the potential to lower many surface water contaminants through the sedimentation of phytoplankton. Based on our results, we estimate that the Saskatchewan Surface Water Quality Objectives (SSWQO) for DJX pit would be met in approximately 45 weeks for Co, 65 weeks for Ni, 15 weeks for U, and 5 weeks for Zn.

  14. Egg fatty acid composition from lake trout fed two Lake Michigan prey fish species.

    USGS Publications Warehouse

    Honeyfield, D.C.; Fitzsimons, J.D.; Tillitt, D.E.; Brown, S.B.

    2009-01-01

    We previously demonstrated that there were significant differences in the egg thiamine content in lake trout Salvelinus namaycush fed two Lake Michigan prey fish (alewife Alosa pseudoharengus and bloater Coregonus hoyi). Lake trout fed alewives produced eggs low in thiamine, but it was unknown whether the consumption of alewives affected other nutritionally important components. In this study we investigated the fatty acid composition of lake trout eggs when females were fed diets that resulted in different egg thiamine concentrations. For 2 years, adult lake trout were fed diets consisting of four combinations of captured alewives and bloaters (100% alewives; 65% alewives, 35% bloaters; 35% alewives, 65% bloaters; and 100% bloaters). The alewife fatty acid profile had higher concentrations of arachidonic acid and total omega-6 fatty acids than the bloater profile. The concentrations of four fatty acids (cis-13, 16-docosadienoic, eicosapentaenoic, docosapentaenoic, and docosahexaenoic acids) were higher in bloaters than in alewives. Although six fatty acid components were higher in lake trout eggs in 2001 than in 2000 and eight fatty acids were lower, diet had no effect on any fatty acid concentration measured in lake trout eggs in this study. Based on these results, it appears that egg fatty acid concentrations differ between years but that the egg fatty acid profile does not reflect the alewife-bloater mix in the diet of adults. The essential fatty acid content of lake trout eggs from females fed alewives and bloaters appears to be physiologically regulated and adequate to meet the requirements of developing embryos.

  15. Spatial characterization of acid rain stress in Canadian Shield Lakes

    NASA Technical Reports Server (NTRS)

    Tanis, F. J.; Marshall, E. M.

    1989-01-01

    The lake acidification in Northern Ontario was investigated using LANDSAT TM to sense lake volume reflectance and also to provide important vegetation and terrain characteristics. The purpose of this project was to determine the ability of LANDSAT to assess water quality characteristics associated with lake acidification. Results demonstrate that a remote sensor can discriminate lake clarity based upon reflection. The basic hypothesis is that seasonal and multi-year changes in lake optical transparency are indicative of sensitivity to acidic deposition. In many acid-sensitive lakes optical transparency is controlled by the amount of dissolved organic carbon present. Seasonal changes in the optical transparency of lakes can potentially provide an indication of the stress due to acid deposition and loading.

  16. Effect of Macerase, Oxalic Acid, and EGTA on Deep Supercooling and Pit Membrane Structure of Xylem Parenchyma of Peach.

    PubMed

    Wisniewski, M; Davis, G; Arora, R

    1991-08-01

    The object of this study was to determine if calcium cross-linking of pectin in the pit membrane of xylem parenchyma restricts water movement which results in deep supercooling. Current year shoots of ;Loring' peach (Prunus persica) were infiltrated with oxalic acid or EGTA solutions for 24 or 48 hours and then either prepared for ultrastructural analysis or subjected to differential thermal analysis. The effect of 0.25 to 1.0% pectinase (weight/volume) on deep supercooling was also investigated. The use of 5 to 50 millimolar oxalic acid and pectinase resulted in a significant reduction (flattening) of the low temperature exotherm and a distinct swelling and partial degradation of the pit membrane. EGTA (10 millimolar) for 24 or 48 hours shifted the low temperature exotherm to warmer temperatures and effected the outermost layer of the pit membrane. A hypothesis is presented on pectin-mediated regulation of deep supercooling of xylem parenchyma.

  17. Hydrogeologic controls on the groundwater interactions with an acidic lake in karst terrain, Lake Barco, Florida

    USGS Publications Warehouse

    Lee, T.M.

    1996-01-01

    Transient groundwater interactions and lake stage were simulated for Lake Barco, an acidic seepage lake in the mantled karst of north central Florida. Karst subsidence features affected groundwater flow patterns in the basin and groundwater fluxes to and from the lake. Subsidence features peripheral to the lake intercepted potential groundwater inflow and increased leakage from the shallow perimeter of the lake bed. Simulated groundwater fluxes were checked against net groundwater flow derived from a detailed lake hydrologic budget with short-term lake evaporation computed by the energy budget method. Discrepancies between modeled and budget- derived net groundwater flows indicated that the model underestimated groundwater inflow, possibly contributed to by transient water table mounding near the lake. Recharge from rainfall reduced lake leakage by 10 to 15 times more than it increased groundwater inflow. As a result of the karst setting, the contributing groundwater basin to the lake was 2.4 ha for simulated average rainfall conditions, compared to the topographically derived drainage basin area of 81 ha. Short groundwater inflow path lines and rapid travel times limit the contribution of acid-neutralizing solutes from the basin, making Lake Barco susceptible to increased acidification by acid rain.

  18. Chemical hazards from acid crater lakes

    NASA Astrophysics Data System (ADS)

    van Bergen, M. J.; Sumarti, S.; Heikens, A.; Bogaard, T. A.; Hartiyatun, S.

    2003-04-01

    Acid crater lakes, which are hosted by a considerable number of active volcanoes, form a potential threat for local ecosystems and human health, as they commonly contain large amounts of dissolved chemicals. Subsurface seepage or overflow can lead to severe deterioration of the water quality of rivers and wells, as observations around several of these volcanoes have shown. The Ijen crater lake in East Java (Indonesia) is a striking example, as this reservoir of hyperacid (pH<0.5) sulphate, chloride and fluoride-rich water is the source of a ca. 50 km long acid river that transports substantial quantities of potentially toxic elements. A downstream trend of increasing pH from <1 to 2.5-4 is largely due to dilution with moderately acid springs (pH= ca. 4) and neutral tributaries (pH= ca. 7) inside the Ijen caldera. Geochemical controls that regulate element transport are subject to seasonal fluctuations in rainfall. Long-term monitoring has shown that fluoride levels pose some of the most severe environmental threats. Its concentration decreases from ca. 1300 mg/kg in the lake to ca. 10 mg/kg in a coastal area downstream, where virtually all of the river water is used for irrigating rice fields and other cropland. Apart from serious problems for agriculture, our survey of 55 drinking water wells in the irrigation area shows that 50% contain fluoride above the 1.5 ppm WHO limit, in line with the observation that dental fluorosis is widespread among the ca. 100,000 residents of the area. A conspicuous spatial correlation between fluoride concentrations and the irrigation system suggest that long-term (century) infiltration of irrigation water may have affected the quality of groundwater. Fluorosis is also a problem in some villages within the caldera, where well water sources may have a more direct subsurface connection with the lake system. From our observations we conclude that water-quality monitoring is especially needed for health reasons in volcanic areas where

  19. Is acid rain impacting the Sudetic lakes?

    PubMed

    Sienkiewicz, Elwira; Gasiorowski, Michał; Hercman, Helena

    2006-10-01

    The diatoms and Cladocera (Crustacea) remains from two lakes in the Sudets Mountains were analyzed to indicate an influence of acidification induced by anthropogenic factors during the last 150 years. The border area of the Czech Republic, Germany and Poland, the so-called "Black Triangle", has been strongly impacted by developed industry for several decades. The most visible effect of this process is the destruction of mountain forests in the region by acid rains. The diatom communities of Mały Staw and Wielki Staw show that acid rain has strongly affected water biota. Diatom-inferred pH reconstruction suggests major acidification during the last two decades. This process was controlled mainly by anthropogenic factors. Cladoceran records also presented changes of dominant taxa in this period and point to significant changes in living conditions. The discovery of a pH decrease during the last decade is contradictory to emissions data that suggest decrease in industrial pollution.

  20. Geochemical characterization of acid mine lakes in northwest Turkey and their effect on the environment.

    PubMed

    Yucel, Deniz Sanliyuksel; Baba, Alper

    2013-04-01

    Mining activity generates a large quantity of mine waste. The potential hazard of mine waste depends on the host mineral. The tendency of mine waste to produce acid mine drainage (AMD) containing potentially toxic metals depends on the amounts of sulfide, carbonate minerals, and trace-element concentrations found in ore deposits. The acid mine process is one of the most significant environmental challenges and a major source of water pollution worldwide. AMD and its effects were studied in northwest Turkey where there are several sedimentary and hydrothermal mineral deposits that have been economically extracted. The study area is located in Can county of Canakkale province. Canakkale contains marine, lagoon, and lake sediments precipitated with volcanoclastics that occurred as a result of volcanism, which was active during various periods from the Upper Eocene to Plio-Quaternary. Can county is rich in coal with a total lignite reserve >100 million tons and contains numerous mines that were operated by private companies and later abandoned without any remediation. As a result, human intervention in the natural structure and topography has resulted in large open pits and deterioration in these areas. Abandoned open pit mines typically fill with water from runoff and groundwater discharge, producing artificial lakes. Acid drainage waters from these mines have resulted in the degradation of surface-water quality around Can County. The average pH and electrical conductivity of acid mine lakes (AMLs) in this study were found to be 3.03 and 3831.33 μS cm(-1), respectively. Total iron (Fe) and aluminum (Al) levels were also found to be high (329.77 and 360.67 mg L(-1), respectively). The results show that the concentration of most elements, such as Fe and Al in particular, exceed national and international water-quality standards.

  1. Geochemical characterization of acid mine lakes in northwest Turkey and their effect on the environment.

    PubMed

    Yucel, Deniz Sanliyuksel; Baba, Alper

    2013-04-01

    Mining activity generates a large quantity of mine waste. The potential hazard of mine waste depends on the host mineral. The tendency of mine waste to produce acid mine drainage (AMD) containing potentially toxic metals depends on the amounts of sulfide, carbonate minerals, and trace-element concentrations found in ore deposits. The acid mine process is one of the most significant environmental challenges and a major source of water pollution worldwide. AMD and its effects were studied in northwest Turkey where there are several sedimentary and hydrothermal mineral deposits that have been economically extracted. The study area is located in Can county of Canakkale province. Canakkale contains marine, lagoon, and lake sediments precipitated with volcanoclastics that occurred as a result of volcanism, which was active during various periods from the Upper Eocene to Plio-Quaternary. Can county is rich in coal with a total lignite reserve >100 million tons and contains numerous mines that were operated by private companies and later abandoned without any remediation. As a result, human intervention in the natural structure and topography has resulted in large open pits and deterioration in these areas. Abandoned open pit mines typically fill with water from runoff and groundwater discharge, producing artificial lakes. Acid drainage waters from these mines have resulted in the degradation of surface-water quality around Can County. The average pH and electrical conductivity of acid mine lakes (AMLs) in this study were found to be 3.03 and 3831.33 μS cm(-1), respectively. Total iron (Fe) and aluminum (Al) levels were also found to be high (329.77 and 360.67 mg L(-1), respectively). The results show that the concentration of most elements, such as Fe and Al in particular, exceed national and international water-quality standards. PMID:23223936

  2. Acidic lakes and streams in the United States: The role of acidic deposition

    SciTech Connect

    Baker, L.A.; Herlihy, A.T.; Kaufmann, P.R.; Eilers, J.M.

    1991-01-01

    A statistically designed survey of lakes and streams in acid-sensitive areas of the United States, the National Surface Water Survey (NSWS), was used to identify the role of acidic deposition, relative to other factors, in causing acidic conditions in 1,181 lakes and 4,668 streams. Atmospheric deposition is the dominant source of acid anions in 75% of the acidic lakes and 47% of the acidic streams. Organic anions are dominant in one-fourth of the acidic lakes and streams; acidic mine drainage is the dominant acid source in 25% of the acidic streams. Other causes of acidic conditions are relatively unimportant on a regional scale. Nearly all the deposition-dominated acidic systems were found in six well-delineated subpopulations that represent about one-fourth of the NSWS lake population and one-third of the NSWS stream population.

  3. Particle Size (Sieving) and Enthalpy (Acid Calorimetry) Analysis of Single-Pull K East Basin Floor and Pit Sludges

    SciTech Connect

    PR Bredt; CH Delegard; AJ Schmidt; KL Silvers; BM Thornton; S Gano

    2000-12-22

    This report presents the results of particle size analyses and calorimetry testing performed on selected single-pull sludge samples collected from the Hanford K East Basin between December 1998 and June 1999. The samples were collected as isolated cores predominantly from areas that had not been previously sampled (e.g., North Loadout Pit, Dummy Elevator Pit, Tech View Pit), or from areas in which the sludge composition had been altered since the last sampling (e.g., Weasel Pit). Particle size analyses were performed by washing wet sludge samples through a series of four sieves with openings of 250, 500, 1410, and 4000 {micro}m. The loaded sieves were weighed before and after drying to obtain wet and dry particle size distributions. Knowledge of the particle size distribution is needed to design and predict the performance of the systems that will be used to retrieve, transport, and recover sludge. Also, sieving provides an opportunity to observe the components in the sludge. For example, during sieving of the sludge sample from the North Loadout Pit, significant quantities of organic ion exchange beads were observed. The uranium metal content and the particle size of the uranium metal in the K Basin sludge will largely determine the chemical reactivity of the sludge. In turn, the designs for the sludge handling and storage systems must be compatible with the reactivity of the sludge. Therefore, acid calorimetry was performed to estimate the uranium metal content of the sludge. For this testing, sludge samples were dissolved in nitric acid within a calibrated adiabatic calorimeter. The resulting dissolution enthalpy data were then used to discriminate between metallic uranium ({minus}3750 J/g in nitric acid) and uranium oxide ({minus}394 J/g in nitric acid). Results from this testing showed that the single-pull sludge samples contained little or no uranium metal.

  4. Identification and quantification of the caproic acid-producing bacterium Clostridium kluyveri in the fermentation of pit mud used for Chinese strong-aroma type liquor production.

    PubMed

    Hu, Xiao-long; Du, Hai; Xu, Yan

    2015-12-01

    Chinese strong-aroma type liquor (CSAL) is a popular distilled alcoholic beverage in China. It is produced by a complex fermentation process that is conducted in pits in the ground. Ethyl caproate is a key flavor compound in CSAL and is thought to originate from caproic acid produced by Clostridia inhabiting the fermentation pit mud. However, the particular species of Clostridium associated with this production are poorly understood and problematic to quantify by culturing. In this study, a total of 28 closest relatives including 15 Clostridia and 8 Bacilli species in pit muds from three CSAL distilleries, were detected by culture-dependent and -independent methods. Among them, Clostridium kluyveri was identified as the main producer of caproic acid. One representative strain C. kluyveri N6 could produce caproic, butyric and octanoic acids and their corresponding ethyl esters, contributing significantly to CSAL flavor. A real time quantitative PCR assay of C. kluyveri in pit muds developed showed that a concentration of 1.79×10(7) 16S rRNA gene copies/g pit mud in LZ-old pit was approximately six times higher than that in HLM and YH pits and sixty times higher than that in LZ-new pit respectively. This method can be used to improve the management of pit mud microbiology and its impact on CSAL quality. PMID:26267890

  5. Acid rain stimulation of Lake Michigan phytoplankton growth

    USGS Publications Warehouse

    Manny, Bruce A.; Fahnenstiel, G.L.; Gardner, W.S.

    1987-01-01

    Three laboratory experiments demonstrated that additions of rainwater to epilimnetic lake water collected in southeastern Lake Michigan stimulated chlorophyll a production more than did additions of reagent-grade water during incubations of 12 to 20 d. Chlorophyll a production did not begin until 3–5 d after the rain and lake water were mixed. The stimulation caused by additions of rain acidified to pH 3.0 was greater than that caused by additions of untreated rain (pH 4.0–4.5). Our results support the following hypotheses: (1) Acid rain stimulates the growth of phytoplankton in lake water; (2) phosphorus in rain appears to be the factor causing this stimulation. We conclude that acid rain may accelerate the growth of epilimnetic phytoplankton in Lake Michigan (and other similar lakes) during stratification when other sources of bioavailable phosphorus to the epilimnion are limited

  6. Pathways of acid mine drainage to Clear Lake: implications for mercury cycling.

    PubMed

    Shipp, William G; Zierenberg, Robert A

    2008-12-01

    Pore fluids from Clear Lake sediments collected near the abandoned Sulphur Bank Mercury Mine have low pH (locally <4) and elevated sulfate (> or =197 mmol/L), aluminum (> or =52 mmol/L), and iron (> or =28 mmol/L) contents derived from oxidation of sulfide minerals at the mine site. Acid mine drainage (AMD) is entering Clear Lake by advective subsurface flow nearest the mine and by diffusion at greater distances. Oxygen and hydrogen isotope ratios, combined with pore fluid compositions, constrain the sources and pathways of contaminated fluids. Sediment cores taken nearest the mine have the highest concentrations of dissolved sulfate, aluminum, and iron, which are contributed by direct subsurface flow of AMD from sulfide-bearing waste rock. Sediment cores as far as 100 m west of the Clear Lake shoreline show the presence of AMD that originated in the acidic lake that occupies the abandoned Herman Pit at the mine site. High sulfate content in the AMD has the potential to promote the activity of sulfate-reducing bacteria in the organic-rich lake sediments, which leads to methylation of Hg+2, making it both more toxic and bioavailable. Quantitative depletion of pore water sulfate at depth and sulfur isotope values of diagenetic pyrite near 0 per thousand indicate that sulfate availability limits the extent of sulfate reduction in the lake sediments away from the mine. Profiles of pore water sulfate in the sediments near the mine show that excess sulfate is available to support the activity of sulfate-reducing bacteria near the mine site. Enriched isotope values of dissolved sulfate (as high as 17.1 per thousand) and highly depleted isotope values for diagenetic pyrite (as low as -22.6 per thousand) indicate active bacterial sulfate reduction in the AMD-contaminated sediments. Sulfate- and iron-rich acid mine drainage entering Clear Lake by shallow subsurface flow likely needs to be controlled in order to lower the environmental impacts of Hg in the Clear Lake

  7. Pathways of acid mine drainage to Clear Lake: implications for mercury cycling.

    PubMed

    Shipp, William G; Zierenberg, Robert A

    2008-12-01

    Pore fluids from Clear Lake sediments collected near the abandoned Sulphur Bank Mercury Mine have low pH (locally <4) and elevated sulfate (> or =197 mmol/L), aluminum (> or =52 mmol/L), and iron (> or =28 mmol/L) contents derived from oxidation of sulfide minerals at the mine site. Acid mine drainage (AMD) is entering Clear Lake by advective subsurface flow nearest the mine and by diffusion at greater distances. Oxygen and hydrogen isotope ratios, combined with pore fluid compositions, constrain the sources and pathways of contaminated fluids. Sediment cores taken nearest the mine have the highest concentrations of dissolved sulfate, aluminum, and iron, which are contributed by direct subsurface flow of AMD from sulfide-bearing waste rock. Sediment cores as far as 100 m west of the Clear Lake shoreline show the presence of AMD that originated in the acidic lake that occupies the abandoned Herman Pit at the mine site. High sulfate content in the AMD has the potential to promote the activity of sulfate-reducing bacteria in the organic-rich lake sediments, which leads to methylation of Hg+2, making it both more toxic and bioavailable. Quantitative depletion of pore water sulfate at depth and sulfur isotope values of diagenetic pyrite near 0 per thousand indicate that sulfate availability limits the extent of sulfate reduction in the lake sediments away from the mine. Profiles of pore water sulfate in the sediments near the mine show that excess sulfate is available to support the activity of sulfate-reducing bacteria near the mine site. Enriched isotope values of dissolved sulfate (as high as 17.1 per thousand) and highly depleted isotope values for diagenetic pyrite (as low as -22.6 per thousand) indicate active bacterial sulfate reduction in the AMD-contaminated sediments. Sulfate- and iron-rich acid mine drainage entering Clear Lake by shallow subsurface flow likely needs to be controlled in order to lower the environmental impacts of Hg in the Clear Lake

  8. Microbial ecology of acid strip mine lakes in southern Indiana

    SciTech Connect

    Gyure, R.A.

    1986-01-01

    In this study, the author examined the limnology and microbial ecology of two acid strip mine lakes in the Greene-Sullivan State Forest near Dugger, Indiana. Reservoir 29 is a larger lake (225 ha) with water column pH of 2.7 and sediment pH of 3.8. Lake B, a smaller (20 ha) lake to the south of Reservoir 29, also has an acidic water column (pH 3.4) but more neutral sediments (pH 6.2). Both have very high sulfate concentrations: 20-30 mM in the water column and as high as 100 mM in the hypolimnion of Lake B. Low allochthonous carbon and nutrient input characterize these lakes as oligotrophic, although algal biomass is higher than would be expected for this trophic status. In both lakes, algal populations are not diverse, with a few species of single-celled Chlorophyta and euglenoids dominating. Algal biomass is concentrated in a thin 10 cm layer at the hypolimnion/metalimnion interface, although light intensity at this depth is low and severely limits productivity. Bacterial activity based on /sup 14/C-glucose incorporation is highest in the hypolimnion of both lakes, and sulfate-reduction is a dominant process in the sediments. Rates of sulfate-reduction compare with those in other freshwater environments, but are not as high as rates measured in high sulfate systems like saltmarsh and marine sediments.

  9. Control of retinoic acid synthesis and FGF expression in the nasal pit is required to pattern the craniofacial skeleton.

    PubMed

    Song, Y; Hui, J N; Fu, K K; Richman, J M

    2004-12-15

    Endogenous retinoids are important for patterning many aspects of the embryo including the branchial arches and frontonasal region of the embryonic face. The nasal placodes express retinaldehyde dehydrogenase-3 (RALDH3) and thus retinoids from the placode are a potential patterning influence on the developing face. We have carried out experiments that have used Citral, a RALDH antagonist, to address the function of retinoid signaling from the nasal pit in a whole embryo model. When Citral-soaked beads were implanted into the nasal pit of stage 20 chicken embryos, the result was a specific loss of derivatives from the lateral nasal prominences. Providing exogenous retinoic acid residue development of the beak demonstrating that most Citral-induced defects were produced by the specific blocking of RA synthesis. The mechanism of Citral effects was a specific increase in programmed cell death on the lateral (lateral nasal prominence) but not the medial side (frontonasal mass) of the nasal pit. Gene expression studies were focused on the Bone Morphogenetic Protein (BMP) pathway, which has a well-established role in programmed cell death. Unexpectedly, blocking RA synthesis decreased rather than increased Msx1, Msx2, and Bmp4 expression. We also examined cell survival genes, the most relevant of which was Fgf8, which is expressed around the nasal pit and in the frontonasal mass. We found that Fgf8 was not initially expressed along the lateral side of the nasal pit at the start of our experiments, whereas it was expressed on the medial side. Citral prevented upregulation of Fgf8 along the lateral edge and this may have contributed to the specific increase in programmed cell death in the lateral nasal prominence. Consistent with this idea, exogenous FGF8 was able to prevent cell death, rescue most of the morphological defects and was able to prevent a decrease in retinoic acid receptorbeta (Rarbeta) expression caused by Citral. Together, our results demonstrate that

  10. Spatial characterization of acid rain stress in Canadian Shield Lakes

    NASA Technical Reports Server (NTRS)

    Tanis, Fred J.

    1987-01-01

    The acidification of lake waters from airborne pollution is of continental proportions both in North America and Europe. A major concern of the acid rain problem is the cumulative ecosystem damage to lakes and forest. The number of lakes affected in northeastern U.S. and on the Canadian Shield is though to be enormous. How seasonal changes in lake transparency are related to annual acidic load was examined. The relationship between variations in lake acidification and ecophysical units was also examined. The utility of Thematic Mapper based observations to measure seasonal changes in the optical transparency in acid lakes was investigated. The potential for this optical response is related to a number of local ecophysical factors with bedrock geology being, perhaps, the most important. Other factors include sulfate deposition, vegetative cover, and terrain drainage/relief. The area of southern Ontario contains a wide variety of geologies from the most acid rain sensitive granite quartzite types to the least sensitive limestone dolomite sediments. Annual sulfate deposition ranges from 1.0 to 4.0 grams/sq m.

  11. Hydrogeology and ground-water quality of the Chromic Acid Pit site, US Army Air Defense Artillery Center and Fort Bliss, El Paso, Texas

    USGS Publications Warehouse

    Abeyta, Cynthia G.; Thomas, C.L.

    1996-01-01

    The Chromic Acid Pit site is an inactive waste disposal site that is regulated by the Resource Conservation and Recovery Act of 1976. The 2.2-cubic-yard cement-lined pit was operated from 1980 to 1983 by a contractor to the U.S. Army Air Defense Artillery Center and Fort Bliss. The pit, located on the Fort Bliss military reservation, in El Paso, Texas, was used for disposal and evaporation of chromic acid waste generated from chrome plating operations. The site was certified closed in 1989 and the Texas Natural Resources Conservation Commission issued Permit Number HW-50296 (U.S. Environmental Protection Agency Permit Number TX4213720101), which approved and implemented post-closure care for the Chromic Acid Pit site. In accordance with an approved post-closure plan, the U.S. Geological Survey is cooperating with the U.S. Army in evaluating hydrogeologic conditions and ground- water quality at the site. One upgradient and two downgradient ground-water monitoring wells were installed adjacent to the chromic acid pit by a private contractor. Quarterly ground-water sampling of these wells by the U.S. Geological Survey began in December 1993. The Chromic Acid Pit site is situated in the Hueco Bolson intermontane valley. The Hueco Bolson is a primary source of ground water in the El Paso area. City of El Paso and U.S. Army water-supply wells are located on all sides of the study area and are completed 600 to more than 1,200 feet below land surface. The ground-water level in the area of the Chromic Acid Pit site has declined about 25 feet from 1982 to 1993. Depth to water at the Chromic Acid Pit site in September 1994 was about 284 feet below land surface; ground-water flow is to the southeast. Ground-water samples collected from monitoring wells at the Chromic Acid Pit site contained dissolved-solids concentrations of 442 to 564 milligrams per liter. Nitrate as nitrogen concentrations ranged from 2.1 to 2.7 milligrams per liter; nitrite plus nitrate as nitrogen

  12. Extremely acid Permian lakes and ground waters in North America

    USGS Publications Warehouse

    Benison, K.C.; Goldstein, R.H.; Wopenka, B.; Burruss, R.C.; Pasteris, J.D.

    1998-01-01

    Evaporites hosted by red beds (red shales and sandstones), some 275-265 million years old, extend over a large area of the North American mid- continent. They were deposited in non-marine saline lakes, pans and mud- flats, settings that are typically assumed to have been alkaline. Here we use laser Raman microprobe analyses of fluid inclusions trapped in halites from these Permian deposits to argue for the existence of highly acidic (pH < 1) lakes and ground waters. These extremely acidic systems may have extended over an area of 200,000 km2. Modern analogues of such systems may be natural acid lake and groundwater systems (pH ~2-4) in southern Australia. Both the ancient and modern acid systems are characterized by closed drainage, arid climate, low acid-neutralizing capacity, and the oxidation of minerals such as pyrite to generate acidity. The discovery of widespread ancient acid lake and groundwater systems demands a re-evaluation of reconstructions of surface conditions of the past, and further investigations of the geochemistry and ecology of acid systems in general.

  13. Detecting acid precipitation impacts on lake water quality

    NASA Astrophysics Data System (ADS)

    Loftis, Jim C.; Taylor, Charles H.

    1989-09-01

    The United States Environmental Protection Agency is planning to expand its long-term monitoring of lakes that are sensitive to acid deposition effects. Effective use of resources will require a careful definition of the statistical objectives of monitoring, a network design which balances spatial and temporal coverage, and a sound approach to data analysis. This study examines the monitoring objective of detecting trends in water quality for individual lakes and small groups of lakes. Appropriate methods of trend analysis are suggested, and the power of trend detection under seasonal (quarterly) sampling is compared to that of annual sampling. The effects of both temporal and spatial correlation on trend detection ability are described.

  14. THE HERMAN PIT AND ITS ROLE IN MERCURY TRANSPORT AT THE SULPHUR BANK MERCURY MINE SUPERFUND SITE, CLEAR LAKE, CALIFORNIA

    EPA Science Inventory

    The Sulphur Bank Mercury Mine (SBMM) is an abandoned sulphur and cinnabar mine located on the eastern shore of the Oaks Arm of Clear Lake, Lake County, California. SBMM was one of the largest mercury producers in California and has been described as one of the most productive sh...

  15. Similar bacterial community composition in acidic mining lakes with different pH and lake chemistry.

    PubMed

    Kampe, Heike; Dziallas, Claudia; Grossart, Hans-Peter; Kamjunke, Norbert

    2010-10-01

    As extreme environmental conditions strongly affect bacterial community composition (BCC), we examined whether differences in pH-even at low pH-and in iron and sulfate concentrations lead to changes in BCC of acidic mining lakes. Thereby, we tested the following hypotheses: (1) diversity of the bacterial community in acidic lakes decreases with reducing pH, (2) BCC differs between epilimnion and hypolimnion, and (3) BCC in extremely acidic environments does not vary much over time. Therefore, we investigated the BCC of three acidic lakes with different pH values (2.3, 2.7, and 3.2) by denaturing gradient gel electrophoresis (DGGE) and subsequent sequencing of DGGE bands as well as catalyzed reporter deposition-FISH (CARD-FISH). BCC did not significantly vary among the studied lakes nor differ much between water layers. In contrast, BCC significantly changed over time, which is contradictory to our hypotheses. Bacterial communities were dominated by Alpha-, Beta-, and Gammaproteobacteria, whereas Actino- and Acidobacteria rarely occurred. Cell numbers of both free and attached bacteria were positively related to DOC concentration. Overall, low pH and extreme chemical conditions of the studied lakes led to similar assemblages of bacteria with pronounced temporal differences. This notion indicates that temporal changes in environmental conditions including food web structure also affect unique communities of bacteria thriving at low pH.

  16. Sulfur Oxidation, Microbes And Acidity In A Mine Tailings Lake

    NASA Astrophysics Data System (ADS)

    Warren, L. A.; Bernier, L.

    2003-12-01

    Disposal of tailings (waste rock) aqueously is a common approach at mine sites to minimize oxidation of the associated sulfur minerals (pyrrhotite, pyrite) and the associated generation of acidity that accompanies this process. The study site, Moose Lake, receives tailings runoff at a nickel mine in Northern Ontario, which has rendered the lake highly acidic (surface pH values less than 3.5) with high metal loads and on-going acid export to off-site, downstream systems. To investigate the potential influence of microbial processes for acid generation, as well as characterizing any attendant influences for metal behaviour, the biogeochemistry of Moose Lake was characterized on a seasonal and a diel basis during the summer of 2002. Physico-chemical profiles were used to identify the area of strong redox gradient across the thermocline (typically 1 to 2 metres across this zone) on each sampling day. Samples at five depths within this redox gradient, were then collected for Fe3+/Fe2+, SO42-/H2S, metal and microbial samples, in addition to more highly resolved Hydrolab profiling. Samples were collected both during the lighted portion of the day (10am-12pm) and at dusk (6pm-8pm) to evaluate any contributions to S and Fe cycling attributed to photosynthetic activity. Results indicate a clear seasonal increase in acidity in the upper waters of the lake: pH values dropped from 3.19 in May to 2.90 in September. Further, a strong diel trend of increasing acidity (lower pH) from mid morning to dusk was also observed for each sampling period. Biotic control on S processes appears to be important associated with the thermocline region of the lake, whilst surficial processes occurring in the upper one to three meters are more consistent with a dominant abiotic control. Both pathways contribute to acidity generation, however the controls and rates differ. These results and implications for mitigation strategies will be presented.

  17. Influence of Acid Mine Drainage (AMD) on recent phyto- and zooplankton in "the Anthropogenic Lake District" in south-west Poland

    NASA Astrophysics Data System (ADS)

    Sienkiewicz, Elwira; Gasiorowski, Michal

    2015-04-01

    In south-west Poland (central Europe) many the post-mining lakes formed so-called "the Anthropogenic Lake District". Areas, where water comes in contact with lignite beds characterized by high concentration of sulfide minerals are called Acid Mine Drainage (AMD). Pyrite oxidation and other sulfide compounds caused release sulfuric acids and heavy metal ions. These processes caused decline of water pH, sometimes to extremely low pH < 2.8. Presently, pit lakes located in south-west Poland have water pH ranged between 2.7 and 8.9. Differences of water reaction in the mine lakes depend on many factors, such as bedrock buffer capacity, geological structure of carboniferous area, exploitation technique of lignite, methods of filling and water supply of reservoirs and their age. During the evolution of lakes' ecosystems, sulfate-iron-calcium type of waters occurring in acid lakes will transform in alkaline hydrogen-carbonate-calcium type of waters. Due to the different time of the completion of lignite exploitation, lakes' age varied between forty and over one hundred years. Studies showed that younger lakes are more acidic in compare to older. To estimate impact of AMD we analyzed recent diversity of diatoms and Cladocera remains and water chemistry from extremely acidic, relatively young lakes and from alkaline, older water bodies. As we expected, flora and fauna from acidic lakes have shown very low diversity and species richness. Among diatoms, Eunotia exigua (Bréb. ex Kütz.) Rabenhorst and/or E. paludosa Grunow were dominated taxa, while fauna Cladocera did not occurred in lakes with water pH < 3. On this area, exploitation of lignite continued up to 1973. Older lakes were formed in the region where the mine started work in 1880 and lignite mining stopped in 1926. Measurements of pH value in situ point to neutral or alkaline water, but because of the possibility of hysteresis phenomenon, the studies of phyto- and zooplankton have shown if there has already been a

  18. Appearance of Planktothrix rubescens Bloom with [D-Asp3, Mdha7]MC–RR in Gravel Pit Pond of a Shallow Lake-Dominated Area

    PubMed Central

    Vasas, Gábor; Farkas, Oszkár; Borics, Gábor; Felföldi, Tamás; Sramkó, Gábor; Batta, Gyula; Bácsi, István; Gonda, Sándor

    2013-01-01

    Blooms of toxic cyanobacteria are well-known phenomena in many regions of the world. Microcystin (MC), the most frequent cyanobacterial toxin, is produced by entirely different cyanobacteria, including unicellular, multicellular filamentous, heterocytic, and non-heterocytic bloom-forming species. Planktothrix is one of the most important MC-producing genera in temperate lakes. The reddish color of cyanobacterial blooms viewed in a gravel pit pond with the appearance of a dense 3 cm thick layer (biovolume: 28.4 mm3 L−1) was an unexpected observation in the shallow lake-dominated alluvial region of the Carpathian Basin. [d-Asp3, Mdha7]MC–RR was identified from the blooms sample by MALDI-TOF and NMR. Concentrations of [d-Asp3, Mdha7]MC–RR were measured by capillary electrophoresis to compare the microcystin content of the field samples and the isolated, laboratory-maintained P. rubescens strain. In analyzing the MC gene cluster of the isolated P. rubescens strain, a deletion in the spacer region between mcyE and mcyG and an insertion were located in the spacer region between mcyT and mcyD. The insertion elements were sequenced and partly identified. Although some invasive tropical cyanobacterial species have been given a great deal of attention in many recent studies, our results draw attention to the spread of the alpine organism P. rubescens as a MC-producing, bloom-forming species. PMID:24351711

  19. Thiamine and fatty acid content of Lake Michigan Chinook salmon

    USGS Publications Warehouse

    Honeyfield, D.C.; Peters, A.K.; Jones, M.L.

    2008-01-01

    Nutritional status of Lake Michigan Chinook salmon (Oncorhynchus tshawytscha) is inadequately documented. An investigation was conducted to determine muscle and liver thiamine content and whole body fatty acid composition in small, medium and large Chinook salmon. Muscle and liver thiamine concentrations were highest in small salmon, and tended to decrease with increasing fish size. Muscle thiamine was higher in fall than spring in large salmon. The high percentage of Chinook salmon (24-32% in fall and 58-71% in spring) with muscle thiamine concentration below 500 pmol/g, which has been associated with loss of equilibrium and death in other Great Lake salmonines, suggest that Chinook appear to rely less on thiamine than other Great Lakes species for which such low concentrations would be associated with thiamine deficiency (Brown et al. 2005b). A positive correlation was observed between liver total thiamine and percent liver lipids (r = 0.53, P < 0.0001, n = 119). In medium and large salmon, liver lipids were observed to be low in fish with less than 4,000 pmol/g liver total thiamine. In individuals with greater than 4,000 pmol/g liver thiamine, liver lipid increased with thiamine concentration. Individual fatty acids declined between fall and spring. Essential omega-3 fatty acids appear to be conserved as lipid content declined. Arachidonic acid (C20:4n6), an essential omega-6 fatty acid was not different between fall and spring, although the sum of omega-6 (Sw6) fatty acids declined over winter. Elevated concentrations of saturated fatty acids (sum) were observed in whole body tissue lipid. In summary, thiamine, a dietary essential vitamin, and individual fatty acids were found to vary in Lake Michigan Chinook salmon by fish size and season of the year.

  20. Microbial Fe cycling and mineralization in sediments of an acidic, hypersaline lake (Lake Tyrell, Victoria, Australia)

    NASA Astrophysics Data System (ADS)

    Roden, E. E.; Blöthe, M.; Shelobolina, E.

    2009-12-01

    Lake Tyrrell is a variably acidic, hypersaline, Fe-rich lake located in Victoria, Australia. Terrestrial acid saline lakes like Lake Tyrrell may be analogs for ancient Martian surface environments, as well as possible extant subsurface environments. To investigate the potential for microbial Fe cycling under acidic conditions and high salt concentration, we collected sediment core samples during three field trips between 2006 and 2008 from the southern, acidic edge of the lake. Materials from the cores were used for chemical and mineralogical analyses, as well as for molecular (16S rRNA genes) and culture-based microbiological studies. Near-surface (< 1 m depth) pore fluids contained low but detectable dissolved oxygen (ca. 50 uM), significant dissolved Fe(II) (ca. 500 uM), and nearly constant pH of around 4 - conditions conducive to enzymatic Fe(II) oxidation. High concentrations of Fe(III) oxides begin accumulate at a depth of ca. 10 cm, and may reflect the starting point for formation of massive iron concretions that are evident at and beneath the sediment surface. MPN analyses revealed low (10-100 cells/mL) but detectable populations of aerobic, halophilic Fe(II)-oxidizing organisms on the sediment surface and in the near-surface ground water. With culture-dependent methods at least three different halotolerant lithoautotrophic cultures growing on Fe(II), thiosulfate, or tetrathionate from different acidic sites were obtained. Analysis of 16S rRNA gene sequences revealed that these organisms are similar to previous described gamma proteobacteria Thiobacillus prosperus (95%), Halothiobacillus kellyi (99%), Salinisphaera shabanense (95%) and a Marinobacter species. (98%). 16S rRNA gene pyrosequencing data from two different sites with a pH range between 3 and 4.5 revealed a dominance of gamma proteobacteria. 16S rRNA gene pyrosequencing libraries from both cores were dominated by sequences related to the Ectothiorhodospiraceae family, which includes the taxa

  1. Structure and characterization of the glycan moiety of L-amino-acid oxidase from the Malayan pit viper Calloselasma rhodostoma.

    PubMed

    Geyer, A; Fitzpatrick, T B; Pawelek, P D; Kitzing, K; Vrielink, A; Ghisla, S; Macheroux, P

    2001-07-01

    Ophidian L-amino-acid oxidase (L-amino-acid oxygen:oxidoreductase, deaminating, EC 1.4.3.2) is found in the venom of many poisonous snakes (crotalids, elapids and viperids). This FAD-dependent glycoprotein has been studied from several snake species (e.g. Crotalus adamanteus, Crotalus atrox and Calloselasma rhodostoma) in detail with regard to the biochemical and enzymatic properties. The nature of glycosylation, however, as well as the chemical structure(s) of the attached oligosaccharide(s) are unknown. In view of the putative involvement of the glycan moiety in the biological effects of ophidian L-amino-acid oxidase, notably the apoptotic activity of the enzyme, structural knowledge is needed to evaluate its exact function. In this study we report on the glycosylation of L-amino-acid oxidase from the venom of the Malayan pit viper (Calloselasma rhodostoma). Its glycosylation is remarkably homogeneous with the major oligosaccharide accounting for approximately 90% of the total sugar content. Based on detailed analysis of the isolated oligosaccharide by 2D NMR spectroscopies and MALDI-TOF mass spectrometry the glycan is identified as a bis-sialylated, biantennary, core-fucosylated dodecasaccharide. The biological significance of this finding is discussed in light of the biological activities of the enzyme. PMID:11453999

  2. Integrated Water Basin Management Including a Large Pit Lake and a Water Supply Reservoir: The Mero-Barcés Basin

    NASA Astrophysics Data System (ADS)

    Delgado, Jordi; Juncosa-Rivera, Ricardo; Hernández-Anguiano, Horacio; Muñoz-Ibáñez, Andrea

    2016-04-01

    Water resource managers attempt to minimize conflicts among users, preserve the environment as much as possible, and satisfy user necessities at a minimum cost. Several European directives indirectly address mine restoration policies, with a goal of minimizing negative impacts and adding social and environmental value where possible. Water management must consider water sources, ecological flows, flood control, and variability in the demands for urban, industrial, and agricultural uses. In the context of the present study, the city of A Coruña is located in Galicia (NW Spain). The water supply system for this city and surrounding municipalities (~400.000 inhabitants) is based on the Abegondo-Cecebre reservoir. In cases when precipitation is scarce (e.g. no rain for more than seven consecutive months) and there is a seasonal increase in demand significantly stress the supply system so that, as occurred in 2010, shortages and water supply restrictions need to be considered. This is a clear indication of that, at present, the Abegondo-Cecebre reservoir has not enough capacity to cope with a scenario of increasing water demand (due to the vegetative and seasonal increase of population) and hydric stress likely connected with the widely acknowledged climate change. In the present context of monetary resources scarcity and society concern with respect large new public work projects, the construction of a new dam is challenging. However the opportunity provided by the recent flooding of the Meirama open pit (a large mine void that has been forced-flooded for its reclamation and it is located in the headwaters of one of the rivers draining towards the Abegondo-Cecebre reservoir) proves to be a significant new asset that will help to improve the future water management scenarios under the acknowledged uncertain conditions. In this study we have studied in detail the hydrochemistry of the affected systems (lake, river and reservoir) in order to make clear whether or not the

  3. A survey of lakes in the Republic of Ireland: hydrochemical characteristics and acid sensitivity.

    PubMed

    Aherne, Julian; Kelly-Quinn, Mary; Farrell, Edward P

    2002-09-01

    In 1997, as part of a national program to determine and map critical loads, a lake survey was carried out in the Republic of Ireland. In total 200 lakes were sampled, which represents approximately 3.3% of the total lake population. The majority of lakes were situated in remote, high-altitude, acid-sensitive areas along the coastal margins of the country. Lake chemistry was dominated by marine inputs. Approximately 50% of the lakes had DOC > 5 mg L-1 due to the presence of organic soils in a large proportion of the catchments. Nonmarine sulfate concentrations were at background levels (< 20 mu eq L-1) in 50% of the lakes. Exceedance of critical load was observed in 7% of the sampled lakes (13 lakes). However, there are uncertainties in the critical load calculations due to the interference of sea salts and organic acids; accurate estimation under such conditions requires long-term lake and deposition chemistry.

  4. Spatial and spectral characterization of acid rain stress in Canadian Shield lakes

    NASA Technical Reports Server (NTRS)

    Marshall, Elizabeth J.; Tanis, Frederick J.

    1989-01-01

    Results from this study demonstrate that a remote sensor can discriminate lake clarity based upon reflection. The basic hypothesis was that seasonal and multiyear changes in lake optical transparency are indicative of sensitivity to acidic deposition. In many acid-sensitive lakes optical transparency is controlled by the amount of dissolved organic carbon (DOC) present. DOC is a strong absorbing, nonscattering material which has the greatest impact at short visible wavelengths, including Thematic Mapper band 1. Acid-sensitive lakes have high concentrations of aluminum which have been mobilized by acidic components contained in the runoff. Aluminum complexing with DOC is considered to be the primary mechanism to account for observed increases in lake transparency in acid-sensitive lakes. Thus seasonal changes in the optical transparency of lakes should provide an indication of the stress due to acid deposition and loading.

  5. Characteristics of acidic lakes in the eastern United States (journal version)

    SciTech Connect

    Landers, D.H.; Eilers, J.M.; Brakke, D.F.; Kellar, P.E.

    1988-01-01

    Acidic lakes are found in many regions of the world and are especially common in those regions of the temperate northern hemisphere that have received high levels of acidic deposition during the last several decades. The National Lake Survey was a one-time fall sampling of lakes in regions of the United States suspected of containing lakes susceptible to acidic deposition. The sample lakes were statistically selected from all lakes identified on medium-scale topographic maps to permit population estimates to be calculated of the characteristics of lakes in the target populations in the regions surveyed. Acidic lakes were defined as those lakes with acid-neutralizing capacity (ANC) < or = 0 (as determined by Gran analysis). This definition is limiting in that only the lakes with no remaining ANC are included. It is clear that lakes with ANC > 0 may be acidic based on pH; however, the rationale for defining other or additional categories of acidic lakes is beyond the scope of the presentation.

  6. Assessment of lake sensitivity to acidic deposition in national parks of the Rocky Mountains

    USGS Publications Warehouse

    Nanus, L.; Williams, M.W.; Campbell, D.H.; Tonnessen, K.A.; Blett, T.; Clow, D.W.

    2009-01-01

    The sensitivity of high-elevation lakes to acidic deposition was evaluated in five national parks of the Rocky Mountains based on statistical relations between lake acid-neutralizing capacity concentrations and basin characteristics. Acid-neutralizing capacity (ANC) of 151 lakes sampled during synoptic surveys and basin-characteristic information derived from geographic information system (GIS) data sets were used to calibrate the statistical models. The explanatory basin variables that were considered included topographic parameters, bedrock type, and vegetation type. A logistic regression model was developed, and modeling results were cross-validated through lake sampling during fall 2004 at 58 lakes. The model was applied to lake basins greater than 1 ha in area in Glacier National Park (n = 244 lakes), Grand Teton National Park (n = 106 lakes), Great Sand Dunes National Park and Preserve (n = 11 lakes), Rocky Mountain National Park (n = 114 lakes), and Yellowstone National Park (n = 294 lakes). Lakes that had a high probability of having an ANC concentration 3000 m, with 80% of the catchment bedrock having low buffering capacity. The modeling results indicate that the most sensitive lakes are located in Rocky Mountain National Park and Grand Teton National Park. This technique for evaluating the lake sensitivity to acidic deposition is useful for designing long-term monitoring plans and is potentially transferable to other remote mountain areas of the United States and the world.

  7. Acid lake in N.Y. gets relief

    NASA Astrophysics Data System (ADS)

    A pond in the Adirondack Mountains of New York State has received a second soothing dose of baking soda. The 21 tons of sodium bicarbonate should moderate the pond's acidic conditions, lethal to fish and other forms of life.Wolf Pond, 25 miles (40 km) north of Saranac Lake, has developed an extremely low pH (4.5) because of acid rain and the runoff of acidic surface water, combined with very little outflow. The pond was first treated with sodium bicarbonate by t h e New York Department of Environmental Conservation in 1984; afterward the pH rose to about 6.2. Fish stocked by local residents have continued to live in the pond, despite the eventual rebound in its acidity.

  8. Plasma osmotic and electrolyte concentrations of largemouth bass from some acidic Florida lakes

    SciTech Connect

    Canfield, D.E. Jr.; Maceina, M.J.; Nordlie, F.G.; Shireman, J.V.

    1985-05-01

    Five acidic clear (pH 3.7-4.9), three acidic colored (pH 4.1-4.6), and three neutral (pH 6.9-7.3) north-central Florida lakes were surveyed in 1983 to determine plasma osmotic and electrolyte concentrations, growth, and coefficients of condition for largemouth bass Micropterus salmoides floridanus. Plasma osmotic concentrations averaged greater than 273 milliosmoles/kg in fish from acidic colored and circumneutral lakes, but averaged less than 269 milliosmoles/kg in four of the acidic clear lakes. Growth and coefficients of condition of largemouth bass > 305 mm total length in the acidic lakes were significantly lower than in the neutral lakes. Reductions in fish growth and condition, however, could be related to either acidic conditions or lake trophic status. 29 references, 3 tables.

  9. Metals in crayfish from neutralized acidic and non-acidic lakes

    SciTech Connect

    Bagatto, G.; Alikhan, M.A.

    1987-09-01

    Large amounts of acid forming SO/sub 2/, as well as Cu, Ni and other metals are being continuously released into the environment by mining and smelting activities at Sudbury, Ontario, Canada. Consequently, a number of lakes in this region has become both acid and metal stressed. The addition of basic calcium compounds to acidic ponds and lakes has long been recognized as beneficial, as it contributes to increased fish production and water quality. In addition to increases in pH and alkalinity, such additions may reduce water-dissolved metal concentrations, change water transparency and bring about alterations in species diversity. Neutralization experiments have shown that an increase in water alkalinity and DOC may reduce the acute toxicity of Cu to fish. However, the influence of water quality on metal availability and accumulation has received scant attention. Earlier work showed that tissue metal concentrations in crayfish were related to the distance from the emission site. The purpose of the present study is to compare concentrations of six metals in freshwater crayfish from a neutralized acidic lake and a closely situated non-acidic lake. Various tissue concentrations in crayfish are also examined to determine specific tissue sites for these accumulations.

  10. Clustering chlorine reactivity of haloacetic acid precursors in inland lakes.

    PubMed

    Zeng, Teng; Arnold, William A

    2014-01-01

    Dissolved organic matter (DOM) represents the major pool of organic precursors for harmful disinfection byproducts, such as haloacetic acids (HAAs), formed during drinking water chlorination, but much of it remains molecularly uncharacterized. Knowledge of model precursors is thus a prerequisite for understanding the more complex whole water DOM. The utility of HAA formation potential data from model DOM precursors, however, is limited due to the lack of comparability to water samples. In this study, the formation kinetics of dichloroacetic acid (DCAA) and trichloroacetic acid (TCAA), the two predominant HAA species, were delineated upon chlorination of seventeen model DOM precursors and sixty-eight inland lake water samples collected from the Upper Midwest region of the United States. Of particular interest was the finding that the DCAA and TCAA formation rate constants could be grouped into four statistically distinct clusters reflecting the core structural features of model DOM precursors (i.e., non-β-diketone aliphatics, β-diketone aliphatics, non-β-diketone phenolics, and β-diketone phenolics). A comparative approach built upon hierarchical cluster analysis was developed to gain further insight into the chlorine reactivity patterns of HAA precursors in inland lake waters as defined by the relative proximity to four model precursor clusters. This work highlights the potential for implementing an integrated kinetic-clustering approach to constrain the chlorine reactivity of DOM in source waters.

  11. A screening procedure for identifying acid-sensitive lakes from catchment characteristics.

    PubMed

    Berg, N H; Gallegos, A; Dell, T; Frazier, J; Procter, T; Sickman, J; Grant, S; Blett, T; Arbaugh, M

    2005-06-01

    Monitoring of Wilderness lakes for potential acidification requires information on lake sensitivity to acidification. Catchment properties can be used to estimate the acid neutralizing capacity (ANC) of lakes. Conceptual and general linear models were developed to predict the ANC of lakes in high-elevation (> or = 2170 m) Wilderness Areas in California's Sierra Nevada mountains. Catchment-to-lake area ratio, lake perimeter-to-area ratio, bedrock lithology, vegetation cover, and lake headwater location are significant variables explaining ANC. The general linear models were validated against independently collected water chemistry data and were used as part of a first stage screen to identify Wilderness lakes with low ANC. Expanded monitoring of atmospheric deposition is essential for improving the predictability of lake ANC.

  12. Spatial characterization of acid rain stress in Canadian Shield Lakes. Final report

    SciTech Connect

    Tanis, F.J.; Marshall, E.M.

    1989-03-01

    The lake acidification in Northern Ontario was investigated using LANDSAT TM to sense lake volume reflectance and also to provide important vegetation and terrain characteristics. The purpose of this project was to determine the ability of LANDSAT to assess water quality characteristics associated with lake acidification. Results demonstrate that a remote sensor can discriminate lake clarity based upon reflection. The basic hypothesis is that seasonal and multi-year changes in lake optical transparency are indicative of sensitivity to acidic deposition. In many acid-sensitive lakes optical transparency is controlled by the amount of dissolved organic carbon present. Seasonal changes in the optical transparency of lakes can potentially provide an indication of the stress due to acid deposition and loading.

  13. Effects of acidic deposition on in-lake phosphorus availability: a lesson from lakes recovering from acidification.

    PubMed

    Kopáček, Jiří; Hejzlar, Josef; Kaňa, Jiří; Norton, Stephen A; Stuchlík, Evžen

    2015-03-01

    Lake water concentrations of phosphorus (P) recently increased in some mountain areas due to elevated atmospheric input of P rich dust. We show that increasing P concentrations also occur during stable atmospheric P inputs in central European alpine lakes recovering from atmospheric acidification. The elevated P availability in the lakes results from (1) increasing terrestrial export of P accompanying elevated leaching of dissolved organic carbon and decreasing phosphate-adsorption ability of soils due to their increasing pH, and (2) decreasing in-lake P immobilization by aluminum (Al) hydroxide due to decreasing leaching of ionic Al from the recovering soils. The P availability in the recovering lakes is modified by the extent of soil acidification, soil composition, and proportion of till and meadow soils in the catchment. These mechanisms explain several conflicting observations of the acid rain effects on surface water P concentrations.

  14. Effects of acidic deposition on in-lake phosphorus availability: a lesson from lakes recovering from acidification.

    PubMed

    Kopáček, Jiří; Hejzlar, Josef; Kaňa, Jiří; Norton, Stephen A; Stuchlík, Evžen

    2015-03-01

    Lake water concentrations of phosphorus (P) recently increased in some mountain areas due to elevated atmospheric input of P rich dust. We show that increasing P concentrations also occur during stable atmospheric P inputs in central European alpine lakes recovering from atmospheric acidification. The elevated P availability in the lakes results from (1) increasing terrestrial export of P accompanying elevated leaching of dissolved organic carbon and decreasing phosphate-adsorption ability of soils due to their increasing pH, and (2) decreasing in-lake P immobilization by aluminum (Al) hydroxide due to decreasing leaching of ionic Al from the recovering soils. The P availability in the recovering lakes is modified by the extent of soil acidification, soil composition, and proportion of till and meadow soils in the catchment. These mechanisms explain several conflicting observations of the acid rain effects on surface water P concentrations. PMID:25660534

  15. Assessment of lake sensitivity to acidic deposition in national parks of the Rocky Mountains.

    PubMed

    Nanus, L; Williams, M W; Campbell, D H; Tonnessen, K A; Blett, T; Clow, D W

    2009-06-01

    The sensitivity of high-elevation lakes to acidic deposition was evaluated in five national parks of the Rocky Mountains based on statistical relations between lake acid-neutralizing capacity concentrations and basin characteristics. Acid-neutralizing capacity (ANC) of 151 lakes sampled during synoptic surveys and basin-characteristic information derived from geographic information system (GIS) data sets were used to calibrate the statistical models. The explanatory basin variables that were considered included topographic parameters, bedrock type, and vegetation type. A logistic regression model was developed, and modeling results were cross-validated through lake sampling during fall 2004 at 58 lakes. The model was applied to lake basins greater than 1 ha in area in Glacier National Park (n = 244 lakes), Grand Teton National Park (n = 106 lakes), Great Sand Dunes National Park and Preserve (n = 11 lakes), Rocky Mountain National Park (n = 114 lakes), and Yellowstone National Park (n = 294 lakes). Lakes that had a high probability of having an ANC concentration <100 microeq/L, and therefore sensitive to acidic deposition, are located in basins with elevations >3000 m, with <30% of the catchment having northeast aspect and with >80% of the catchment bedrock having low buffering capacity. The modeling results indicate that the most sensitive lakes are located in Rocky Mountain National Park and Grand Teton National Park. This technique for evaluating the lake sensitivity to acidic deposition is useful for designing long-term monitoring plans and is potentially transferable to other remote mountain areas of the United States and the world. PMID:19544737

  16. Assessment of lake sensitivity to acidic deposition in national parks of the Rocky Mountains.

    PubMed

    Nanus, L; Williams, M W; Campbell, D H; Tonnessen, K A; Blett, T; Clow, D W

    2009-06-01

    The sensitivity of high-elevation lakes to acidic deposition was evaluated in five national parks of the Rocky Mountains based on statistical relations between lake acid-neutralizing capacity concentrations and basin characteristics. Acid-neutralizing capacity (ANC) of 151 lakes sampled during synoptic surveys and basin-characteristic information derived from geographic information system (GIS) data sets were used to calibrate the statistical models. The explanatory basin variables that were considered included topographic parameters, bedrock type, and vegetation type. A logistic regression model was developed, and modeling results were cross-validated through lake sampling during fall 2004 at 58 lakes. The model was applied to lake basins greater than 1 ha in area in Glacier National Park (n = 244 lakes), Grand Teton National Park (n = 106 lakes), Great Sand Dunes National Park and Preserve (n = 11 lakes), Rocky Mountain National Park (n = 114 lakes), and Yellowstone National Park (n = 294 lakes). Lakes that had a high probability of having an ANC concentration <100 microeq/L, and therefore sensitive to acidic deposition, are located in basins with elevations >3000 m, with <30% of the catchment having northeast aspect and with >80% of the catchment bedrock having low buffering capacity. The modeling results indicate that the most sensitive lakes are located in Rocky Mountain National Park and Grand Teton National Park. This technique for evaluating the lake sensitivity to acidic deposition is useful for designing long-term monitoring plans and is potentially transferable to other remote mountain areas of the United States and the world.

  17. A Demonstration of Acid Rain and Lake Acidification: Wet Deposition of Sulfur Dioxide.

    ERIC Educational Resources Information Center

    Goss, Lisa M.

    2003-01-01

    Introduces a science demonstration on the dissolution of sulfuric oxide emphasizing the concept of acid rain which is an environmental problem. Demonstrates the acidification from acid rain on two lake environments, limestone and granite. Includes safety information. (YDS)

  18. A Demonstration of Acid Rain and Lake Acidification: Wet Deposition of Sulfur Dioxide

    NASA Astrophysics Data System (ADS)

    Goss, Lisa M.

    2003-01-01

    A demonstration showing acid rain and lake acidification is described. In this demonstration, SO2 gas is generated in a large graduated cylinder and then dissolved in water droplets from a simple spray bottle. The droplets carry the acid into simulated lakes, one of which includes solid CaCO3 to mimic limestone's natural buffering capacity.

  19. Thermal and trophic stability of deeper Maine lakes in granite waterhsheds implacted by acid deposition

    SciTech Connect

    Stauffer, R.E.; Wittchen, B.D. )

    1990-09-01

    Acid deposition can lead to lake and watershed acidification, increases in lake transparency, and reduction in thermal stability and hypolimnetic oxygen deficits. On the basis of lake surveys during August-September 1985, we determined to what extent the deeper (maximum depth z{sub m}{gt}17 m) Maine lakes in acid-sensitive granitic watersheds have registered changes in temperature and oxygen stratification, as compared to 1938-1942, when G.P. Cooper performed the earliest scientific surveys of the state's lakes. After correcting for small but geographically consistent interannual differences in summer hypolimnetic temperatures related to spring turnover, and weather-dependent differences in mixed layer depth, there has been no significant change in thermal stratification in these Maine lakes over approximately 43 years. On the basis of specific historical contrasts in the late summer metalimnetic, hypolimnetic, and bathylimnetic oxygen concentrations there has been no significant change in lake trophic state or transparency.

  20. Catchment and atmospheric effects on acidity of lakes in the northeastern United States

    SciTech Connect

    Davis, R.B.; Anderson, D.S.; Rhodes, T.E.

    1995-06-01

    Sedimentary evidence from 12 lakes in northeastern United States reveals that both catchment and atmospheric processes have caused changes in lake acidity. Diatom remains indicate pH 5.2 to 5.8 (one lake 6.8) for one to two centuries before impacts on the catchment by Euro-americans. These low-alkalinity lakes were very sensitive to altered fluxes of base cations and acids. Several lakes increased in pH by 0.2 to 0.6 unit in the 1800s and early 1900s when their catchments were logged. Re-acidification of some of the lakes was initially due to forest succession. Older sediment from one of the lakes also shows alkalization by natural disturbance, and acidification paralleling forest succession. However, much of the recent acidification, to uniquely low levels by the 1970s is due to high sulfur deposition.

  1. Organic matter in sediments of an acidic mining lake as assessed by lipid analysis. Part I: fatty acids.

    PubMed

    Poerschmann, Juergen; Koschorreck, Matthias; Górecki, Tadeusz

    2012-01-01

    Fatty acid (FA) patterns of sediments collected from the bottom of an acidic mine pit lake (AML) at different depths (surface sediment: 0 to 1cm; deep sediment: 4 to 5 cm) were studied to characterize microbial communities and the sources of sedimentary organic matter (SOM). Studies were performed on the molecular level utilizing source-specific, diagnostic FA biomarkers. The biomarker-based approach has been used widely in marine sediment studies, but has not been applied for sediments from AMLs so far. Combined FA concentrations in the surface sediment were higher compared to those in the deep sediment (497 vs. 127 μg g(-1)d.w., respectively). This was related to deposition of autochthonous biomass and higher terrestrial plants onto the surface sediment, as well as--to lesser extent--with higher bacterial activity on the sediment-water interface. The FA distribution in both sediments was characterized by a strong even-over-odd preference and was bimodal in nature: there was a cluster at nC(14)-nC(18) characteristic of chiefly autochthonous (algal and bacterial) SOM production, and another cluster at nC(22-28) related to input from higher plants. The FA distribution in the surface sediment pointed to higher terrestrial input compared to autochthonous contribution to SOM (67%:33%) as an estimate. Fingerprinting of viable bacteria was accomplished through signature FA markers including branched C(15) and C(17) surrogates, cyclopropanoic acids, 3-hydroxy (OH) acids and monounsaturated surrogates with unusual double bond localization. The abundance of Gram-negative bacteria was higher in the surface sediment as evidenced by total diagnostic 3-OH-fatty acids (37 μg g(-1) versus 25 μg g(-1)). Potential source taxa in both sediment layers included acidophilic iron- and sulfur-oxidizing bacteria including Acidithiobacillus ferrooxidans. High abundances of terminally branched C(15) and C(17) surrogates in both sediments pointed to sulfate- and iron-reducing bacteria

  2. Technical issues associated with in situ vitrification of the INEL Subsurface Disposal Area. Volume 2, Application of technical issues to the Acid Pit

    SciTech Connect

    Stoots, C.M.; Bates, S.O.; Callow, R.A.; Campbell, K.A.; Farnsworth, R.K.; Gratson, G.K.; McKellar, M.G.; Nickelson, D.F.; Slater, C.E.

    1992-01-01

    In situ vitrification (ISV) has been identified as an alternative technology for remediation of the Acid Pit and Transuranic Pits and Trenches (TRU-PTs) that are present at the Idaho National Engineering Laboratory (INEL) Subsurface Disposal Area (SDA). However, a number of technical issues exist that must be resolved before ISV can be considered applicable to these waste sites. To assist in the ISV technology evaluation, an ISV Steering Committee was formed to identify, prioritize, and develop closure roadmaps for technical issues associated with ISV application at the INEL SDA. The activities of the ISV Steering Committee are summarized in three volumes of this report. Volume 1 identifies the systematic approach used to identify and prioritize the ISV technical issues, and briefly discusses the methodology that will be employed to resolve these issues. This document Volume 2 and Volume 3 discusses each technical issue in greater detail and suggest specific closure roadmaps to be used in resolving technical issues associated with ISV at the SDA Acid Pit and TRU-PTs, respectively.

  3. Composition of Humic Acids of the Lake Baikal Sediments

    NASA Astrophysics Data System (ADS)

    Vishnyakova, O.; Chimitdorzhieva, G.; Andreeva, D.

    2012-04-01

    Humic substances are the final stage of the biogeochemical transformation of organic matter in the biosphere. Its natural compounds are found not only in soil, peat, coal, and sediments of basins. Chemical composition and properties of humic substances are determined by the functioning of the ecosystem as a whole. Therefore the study of the unique Lake Baikal sediments can provide information about their genesis, as well as the processes of organic matter transformation. For this purpose, preparations of humic acids (HA) were isolated by alkaline extraction method. The composition of HA was investigated by the elemental analyzer CHNS/O PerkinElmer Series II. Various located sediments of the Lake Baikal were the objects of the study: 1 - Chivyrkuisky Bay, 2 - Kotovo Bay, 3 - Selenga river delta near Dubinino village, 4 - Selenga river delta near Murzino village. Data on the elemental composition of HA in terms of ash-free portion show that the carbon content (CC) is of 50-53% with a maximum value in a sample 3, and minimum - in a sample 2. Such values are characteristic also for the soils with low biochemical activity. The hydrogen content is of 4,2-5,3%, a maximum value is in a sample 1. Data recalculation to the atomic percentages identified following regularities. The CC of HA is of 35-39 at. %. Hydrogen content is of 37-43 at. %. According to the content of these elements investigated substances are clearly divided into two groups: HA of the sediments of the Lake Baikal and river Selenga delta. The magnitude of the atomic ratio H/C can be seen varying degrees of condensation of the molecules of humic acids. The high atomic ratio H/C in HA of the former group indicates the predominance of aliphatic structures in the molecules. Humic acids of the later group are characterized by a low value H/C (<1), suggesting a large proportion of aromatic components in HA composition. In sediments of the Selenga river delta there is an addition of organic matter of terrigenous

  4. Characteristics of three acidic lakes in Kejimkujik National Park, Nova Scotia, Canada.

    PubMed

    Kerekes, J; Freedman, B

    1989-01-01

    This report summarizes a study of the chemical and biological characteristics of three oligotrophic lakes located in a region that receives a moderately acidic precipitation (mean annual pH 4.5-4.6), and a sulfate deposition of about 20 kg/ha/yr. The two brownwater lakes are relatively acidic (pH 4.5 and 4.8), and much of their acidity is attributable to organic anions. The brownwater lakes also have a large concentration of aluminum and iron, but these are bound to dissolved organic matter and are relatively non-toxic to biota. Average phytoplankton production was largest in the clearwater lake. This was due to its relatively deep euphotic zone, since the average unit-volume productivity did not differ much among the lakes. In fact, productivity at light optimum was largest in the most acidic brownwater lake, probably because of its larger phosphorus concentration. The clearwater lake had extensive macrophyte vegetation, which covered its bottom to a depth of 6.5 m. In the brownwater lakes, macrophytes were confined to shallow nearshore water because of the limited water transparency. Zooplankton density and biomass were largest in the most acidic brownwater lake, probably because of allochthonous organic particulates and little fish predation. Benthic invertebrates were abundant in all three lakes, and were dominated by insects, especially Chironomids. Lakes in the study area appear to be sustaining fish populations at more acidic pHs than elsewhere. This may be due to the large concentration of dissolved organic matter in many lakes, which complexes and partially detoxifies metals such as aluminum.

  5. Pitting corrosion resistance of nickel-titanium rotary instruments with different surface treatments in seventeen percent ethylenediaminetetraacetic Acid and sodium chloride solutions.

    PubMed

    Bonaccorso, Antonio; Tripi, Teresa Roberta; Rondelli, Gianni; Condorelli, Guglielmo Guido; Cantatore, Giuseppe; Schäfer, Edgar

    2008-02-01

    This study evaluated the pitting corrosion resistance of nickel-titanium (NiTi) rotary instruments with different surface treatments in 17% ethylenediaminetetraacetic acid (EDTA) and NaCl solutions. Electropolished RaCe instruments were allocated to group A, non-electropolished RaCe instruments to group B, and physical vapor deposition (PVD)-coated Alpha files to group C (10 instruments per group). Electrochemical measurements were carried out by using a potentiostat for galvanic current measurements. On the basis of electrochemical tests, no localized corrosion problems are to be expected in EDTA. In NaCl, pitting potential occurred at higher values for the electropolished and PVD instruments, indicating an increased corrosion resistance. There appears to be a risk of corrosion for NiTi instruments without surface treatments in contact with NaCl. NiTi files with PVD and electropolishing surface treatments showed an increase corrosion resistance.

  6. Pitted keratolysis*

    PubMed Central

    de Almeida Jr, Hiram Larangeira; Siqueira, Rodrigo Nunes; Meireles, Renan da Silva; Rampon, Greice; de Castro, Luis Antonio Suita; Silva, Ricardo Marques e

    2016-01-01

    Pitted keratolysis is a skin disorder that affects the stratum corneum of the plantar surface and is caused by Gram-positive bacteria. A 30-year-old male presented with small punched-out lesions on the plantar surface. A superficial shaving was carried out for scanning electron microscopy. Hypokeratosis was noted on the plantar skin and in the acrosyringium, where the normal elimination of corneocytes was not seen. At higher magnification (x 3,500) bacteria were easily found on the surface and the described transversal bacterial septation was observed. PMID:26982791

  7. Physical and chemical limnological study of an acid mine lake in Sullivan County, Indiana

    SciTech Connect

    Broomall, P.A.

    1992-01-01

    Southwestern Indiana has numerous lakes developed in abandoned coal mine spoils which support recreational sports fisheries. Some lakes, due to exposure to acid mine drainage from coal wastes and pyritic spoils, are unsuitable habitats for fisheries development. This study examines a publicly owned acid mine lake with an area of approximately 51 ha, following reclamation and elimination of acid producing areas in its drainage basin. Fifteen physico-chemical sample collections were made over a thirteen month period (1991--1992). Parameters sampled included pH, total acidity, iron, manganese, and aluminum. Comparisons were made to historic pre-reclamation water quality data and to established models of acid mine lake recovery. Due to the local topography and exposure to prevailing winds, the lake was generally well mixed throughout the study. Virtually no summer stratification was found, but typical winter season stratification occurred. The water column was well oxygenated throughout the study. Secchi disk transparency varied from 2.5 m to clear to lake bottom (6 m). This study found no significant change in lake water pH (2.9--3.0 to 3.0--3.2 s.u.) since reclamation activities in 1988. However, changes in total acidity and total metal concentrations had occurred since reclamation which suggested that the lake was in early recovery stages. No trends in water quality improvement were determined which could assist in planning toward the eventual establishment of a sports fishery.

  8. Acid precipitation effects on algal productivity and biomass in Adirondack Mountain lakes

    SciTech Connect

    Hendrey, G.R.

    1982-12-01

    Relationships between phytoplankton communities and lake acidity in three Adirondack Mountain lakes were studied at Woods Lake (pH ca. 4.9), Sagamore Lake (pH ca. 5.5), and Panther Lake (pH ca. 7.0). Species numbers decrease with increasing acidity. Patterns of increasing biomass and productivity in Woods Lake may be atypical of similar oligotrophic lakes in that they develop rather slowly to maxima six weeks after ice-out, instead of occurring very close to ice-out. Contributions of netplankton, nannoplankton and ultraplankton to productivity per m/sup 2/ show that the smaller plankton are relatively more important in the more acid lakes. This pattern could be determined by nutrient availability (lake acidification is suspected of leading to decreased availability of phosphorus). This was consistent with a hypothesis that microbial heterotrophic activity is reduced with increasing acidity, but the smaller phytoplankton may be more leaky at low pH. 11 references, 2 tables.

  9. Perfluorinated acids in air, rain, snow, surface runoff, and lakes: relative importance of pathways to contamination of urban lakes.

    PubMed

    Kim, Seung-Kyu; Kannan, Kurunthachalam

    2007-12-15

    Concentrations of perfluorinated acids (PFAs) were measured in various environmental matrices (air, rain, snow, surface runoff water, and lake water) in an urban area, to enable identification of sources and pathways of PFAs to urban water bodies. Total PFA concentrations ranged from 8.28 to 16.0 pg/ m3 (mean 11.3) in bulk air (sum of vapor and particulate phases), 0.91 to 13.2 ng/L (6.19) in rainwater, 0.91 to 23.9 ng/L (7.98) in snow, 1.11-81.8 ng/L (15.1 ng/L) in surface runoff water (SRW), and 9.49 to 35.9 ng/L (21.8) in lake water. Perfluorooctanoic acid (PFOA) was the predominant compound, accounting for > 35% of the total PFA concentrations, in all environmental matrices analyzed. Concentrations and relative compositions of PFAs in SRW were similar to those found for urban lakes. SRW contributes to contamination by PFOA in urban lakes. The measured concentration ratios of FTOH to PFOA in air were 1-2 orders of magnitude lower than the ratios calculated based on an assumption of exclusive atmospheric oxidation of FTOHs. Nevertheless, the mass balance analysis suggested the presence of an unknown input pathway that could contribute to a significant amount of total PFOA loadings to the lake. Flux estimates of PFOA at the air-water interface in the urban lake suggest net volatilization from water.

  10. Cycling of iron and trace metals in the sediments of acidic lakes

    SciTech Connect

    Gubala, C.P.

    1988-01-01

    This study focused on four lakes receiving acidic deposition located in the Adirondack Park, New York, U.S.A. The biogeochemistry of sediments and interstitial water along a depth transect in Big Moose, Lake was examined by chemical analysis of sediment and pore water. Solid phases of iron, manganese, aluminum, lead and zinc were quantified, using a sequential chemical extraction process. {sup 210}Pb dating, and equilibrium and diffusion transport modeling were used to assess the degree of post-depositional reprocessing of these metals. The sediment chemistry of Dart Lake, Lake Rondaxe and South Lake, were compared to the sediment processes observed in Big Moose Lake to assess inter-lake variability.

  11. Parent Body Influences on Amino Acids in the Tagish Lake Meteorite

    NASA Technical Reports Server (NTRS)

    Glavin, D. P.; Callahan, M. P.; Dworkin, J. P.; Elsila, J. E.; Herd, C. D. K.

    2010-01-01

    The Tagish Lake meteorite is a primitive C2 carbonaceous chondrite with a mineralogy, oxygen isotope, and bulk chemical. However, in contrast to many CI and CM carbonaceous chondrites, the Tagish Lake meteorite was reported to have only trace levels of indigenous amino acids, with evidence for terrestrial L-amino acid contamination from the Tagish Lake meltwater. The lack of indigenous amino acids in Tagish Lake suggested that they were either destroyed during parent body alteration processes and/or the Tagish Lake meteorite originated on a chemically distinct parent body from CI and CM meteorites where formation of amino acids was less favorable. We recently measured the amino acid composition of three different lithologies (11h, 5b, and 11i) of pristine Tagish Lake meteorite fragments that represent a range of progressive aqueous alteration in order 11h < 5b < 11i as inferred from the mineralogy, petrology, bulk isotopes, and insoluble organic matter structure. The distribution and enantiomeric abundances of the one- to six-carbon aliphatic amino acids found in hot-water extracts of the Tagish Lake fragments were determined by ultra performance liquid chromatography fluorescence detection and time of flight mass spectrometry coupled with OPA/NAC derivatization. Stable carbon isotope analyses of the most abundant amino acids in 11h were measured with gas chromatography coupled with quadrupole mass spectrometry and isotope ratio mass spectrometry.

  12. Paleolimnological Diatom Studies of Acidification of Lakes by Acid Rain: An Application of Quaternary Science

    NASA Astrophysics Data System (ADS)

    Davis, Ronald B.

    The methods of Quaternary paleoecology have proven useful for understanding the effects of anthropogenic acid deposition on lakes. The pH history of lakes has been inferred from diatom remains in 210Pb dated cores of sediment. In several of these studies, the cores have also been analysed for chrysophyte scales, trace metals (Pb, Zn, V, Cu), soot, and polycyclic aromatic hydrocarbons. Combined with historical studies of watershed vegetation and disturbance, these approaches have produced important insights relating to the effects on lakes of acid deposition: (1) certain clear water lakes with present pH 4.3-5.0 have rapidly acidified in recent decades; (2) these lakes were acidic (pH 5.0-6.4) prior to the acidification; (3) the most likely cause of the acidification is acid deposition; (4) the acidification began decades after high levels of acid deposition had been reached; and (5) in certain lakes acidification may have caused a marked decrease in humics, reducing the availability of organic ligands for 'detoxification' of metal ions (e.g. Al) mobilized by acidification. Diatom analyses have also revealed long term lake acidification in Late-glacial and Holocene time before the Industrial Revolution. This acidification is much slower than the modern acidification. The present pHs in anthropogenically acidified lakes are unprecedentedly low.

  13. Spatial characterization of acid rain stress in Canadian Shield lakes. Progress report, 1 August 1985-1 February 1986

    SciTech Connect

    Tanis, F.J.

    1986-01-01

    The acidification of lake waters from airborne pollutants is of continental proportions both in North America and Europe. A major concern of the acid rain problem is the cumulative ecosystem damage to lakes and forest. The number of lakes affected in northeastern United States and on the Canadian Shield is though to be enormous. The principle objective is to examine how seasonal changes in lake water transparency are related to annual acidic load. Further, the relationship between variations in lake acidification and ecophysical units is being examined. Finally, the utility of Thematic Mapper (TM) based observations to measure seasonal changes in the optical transparency in acid lakes is being investigated.

  14. Geochemistry, mineralogy, and chemical modeling of the acid crater lake of Kawah Ijen Volcano, Indonesia

    NASA Astrophysics Data System (ADS)

    Delmelle, Pierre; Bernard, Alain

    1994-06-01

    The Kawah Ijen volcano—with a record of phreatic eruptions—has its 1000 m wide crater filled with a lake that has existed for at least one century. At present, the lake waters are hot ( T ≈ 37° C), strongly mineralized (TDS = 105 g/L) and extremely acidic ( pH ≈ 0.4). By its volume, the Javanese lake is probably the largest accumulation in the world of such acidic waters. Mineralogy of the suspended solids within the lake waters suggests that concentrations of Si, Ca, Ti, and Ba are controlled by precipitation of silica, gypsum, anatase, and barite. Lake sediment is composed of chemical precipitates with composition similar to the suspended solids. Thermodynamic calculations predict that the lake waters have reached equilibrium with respect to α-cristobalite, barite, gypsum, anglesite, celestite, and amorphous silica, in agreement with the analytical observations. Significant concentrations of ferric iron suggest that the current lake waters are fairly oxidized. Sulfides are absent in the water column but are always present in the native S spherules that form porous aggregates which float on the lake. The presence of native S provides direct evidence of more reduced conditions at the lake floor where H 2S is probably being injected into the lake. With progressive addition of H 2S to the acid waters, native S, pyrite, and enargite are theoretically predicted to be saturated. Reactions between upward streaming H 2S-bearing gases discharged by subaqueous fumaroles, and metals dissolved in the acidic waters could initiate precipitation of these sulfides. A model of direct absorption of hot magmatic gases into cool water accounts for the extreme acidity of the crater lake. Results show that strongly acidic, sulfate-rich solutions are formed under oxidizing conditions at high gas/water ratios. Reactions between the acidic fluids and the Ijen andesite were modeled to account for elevated cation concentrations in lake water. Current concentrations of conservative

  15. Effect of atmospheric sulfur pollutants derived from acid precipitation on the benthic dynamics of lakes

    SciTech Connect

    Mitchell, M.J.

    1982-11-01

    Sulfuric acid is a major contributor to acid precipitation in the United States. The relationship of acid precipitation to the sulfur dynamics of three lakes in New York was studied. For South Lake, which has probably been acidified, the sulfur profile in the sediment corresponded to historical changes in anthropogenic sulfur inputs. In all three study lakes, the organic sulfur constituents, which generally have been ignored in limnological investigations, played a major role in sulfur dynamics. The transformations and fluxes of inorganic and organic sulfur differed among the lakes and reflected characteristic abiotic and biotic properties, including productivity parameters. The community structure and secondary production of the invertebrate benthos were ascertained and, for South Lake, were similar to other acidified lakes. The importance of benthic insects on sulfur dynamics was demonstrated. Further studies on sulfur in lakes will enhance the understanding of the role of these anthropogenic inputs on lake systems and permit a more accurate appraisal of the present and future impacts of acidic deposition on water quality. 10 references.

  16. Hydrogeologic comparison of an acidic-lake basin with a neutral-lake basin in the West-Central Adirondack Mountains, New York

    USGS Publications Warehouse

    Peters, N.E.; Murdoch, Peter S.

    1985-01-01

    Two small headwater lake basins that receive similar amounts of acidic atmospheric deposition have significantly different lake outflow pH values; pH at Panther Lake (neutral) ranges from about 4.7 to 7; that at Woods Lake (acidic) ranges from about 4.3 to 5. A hydrologic analysis, which included monthly water budgets, hydrograph analysis, examination of flow duration and runoff recession curves, calculation of ground-water storage, and an analysis of lateral flow capacity of the soil, indicates that differences in lakewater pH can be attributed to differences in the ground-water contribution to the lakes. A larger percentage of the water discharged from the neutral lake is derived from ground water than that from the acidic lake. Ground water has a higher pH resulting from a sufficiently long residence time for neutralizing chemical reactions to occur with the till. The difference in ground-water contribution is attributed to a more extensive distribution of thick till (<3m) in the neutral-lake basin than in the acidic-lake basin; average thickness of till in the neutral-lake basin is 24m whereas that in the other is 2.3m. During the snowmelt period, as much as three months of accumulated precipitation may be released within two weeks causing the lateral flow capacity of the deeper mineral soil to be exceeded in the neutral-lake basin. This excess water moves over and through the shallow acidic soil horizons and causes the lakewater pH to decrease during snowmelt.Two small headwater lake basins that receive similar amounts of acidic atmospheric deposition have significantly different lake outflow pH values; pH at Panther Lake (neutral) ranges from about 4. 7 to 7; that at Woods Lake (acidic) ranges from about 4. 3 to 5. A hydrologic analysis, which included monthly water budgets, hydrograph analysis, examination of flow duration and runoff recession curves, calculation of ground-water storage, and an analysis of lateral flow capacity of the soil, indicates that

  17. The evolution of a mining lake - From acidity to natural neutralization.

    PubMed

    Sienkiewicz, Elwira; Gąsiorowski, Michał

    2016-07-01

    Along the border of Poland and Germany (central Europe), many of the post-mining lakes have formed "an anthropogenic lake district". This study presents the evolution of a mining lake ecosystem (TR-33) based on subfossil phyto- and zooplankton, isotopic data (δ(13)C, δ(15)N), elemental analyses of organic carbon and nitrogen (C/N ratio and TOC) and sedimentological analyses. Recently, lake TR-33 became completely neutralized from acidification and an increase in eutrophication began a few years ago. However, the lake has never been neutralized by humans; only natural processes have influenced the present water quality. From the beginning of the existence of the lake (1920s) to the present, we can distinguish four stages of lake development: 1) very shallow reservoir without typical lake sediments but with a sand layer containing fine lignite particles and very poor diatom and cladoceran communities; 2) very acidic, deeper water body with increasing frequencies of phyto- and zooplankton; 3) transitional period (rebuilding communities of diatoms and Cladocera), meaning a deep lake with benthic and planktonic fauna and flora with wide ecological tolerances; and 4) a shift to circumneutral conditions with an essential increase in planktonic taxa that prefer more fertile waters (eutrophication). In the case of lake TR-33, this process of natural neutralization lasted approximately 23years.

  18. Ground-water quality, water year 1995, and statistical analysis of ground-water-quality data, water years 1994-95, at the Chromic Acid Pit site, US Army Air Defense Artillery Center and Fort Bliss, El Paso, Texas

    USGS Publications Warehouse

    Abeyta, Cynthia G.; Roybal, R.G.

    1996-01-01

    The Chromic Acid Pit site is an inactive waste disposal site that is regulated by the Resource Conservation and Recovery Act of 1976. The 2.2-cubic-yard cement-lined pit was operated from 1980 to 1983 by a contractor to the U.S. Army Air Defense Artillery Center and Fort Bliss. The pit, located on the Fort Bliss military reservation in El Paso, Texas, was used for disposal and evaporation of chromic acid waste generated from chrome plating operations. The site was closed in 1989, and the Texas Natural Resources Conservation Commission issued permit number HW-50296 (U.S. Environmental Protection Agency number TX4213720101), which approved and implemented post-closure care for the Chromic Acid Pit site. In accordance with an approved post-closure plan, the U.S. Geological Survey is cooperating with the U.S. Army in monitoring and evaluating ground-water quality at the site. One upgradient ground-water monitoring well (MW1) and two downgradient ground-water monitoring wells (MW2 and MW3), installed adjacent to the chromic acid pit, are monitored on a quarterly basis. Ground-water sampling of these wells by the U.S. Geological Survey began in December 1993. The ground-water level, measured in a production well located approximately 1,700 feet southeast of the Chromic Acid Pit site, has declined about 29.43 feet from 1982 to 1995. Depth to water at the Chromic Acid Pit site in September 1995 was 284.2 to 286.5 feet below land surface; ground-water flow at the water table is assumed to be toward the southeast. Ground-water samples collected from monitoring wells at the Chromic Acid Pit site during water year 1995 contained dissolved- solids concentrations of 481 to 516 milligrams per liter. Total chromium concentrations detected above the laboratory reporting limit ranged from 0.0061 to 0.030 milligram per liter; dissolved chromium concentrations ranged from 0.0040 to 0.010 milligram per liter. Nitrate as nitrogen concentrations ranged from 2.1 to 2.8 milligrams per

  19. No nitrification in lakes below pH 3.

    PubMed

    Jeschke, Christina; Falagán, Carmen; Knöller, Kay; Schultze, Martin; Koschorreck, Matthias

    2013-12-17

    Lakes affected by acid mine drainage (AMD) or acid rain often contain elevated concentrations of ammonium, which threatens water quality. It is commonly assumed that this is due to the inhibition of microbial nitrification in acidic water, but nitrification was never directly measured in mine pit lakes. For the first time, we measured nitrification by (15)NH4Cl isotope tracer addition in acidic as well as neutral mine pit lakes in Spain and Germany. Nitrification activity was only detected in neutral lakes. In acidic lakes no conversion of (15)NH4(+) to (15)NO3(-) was observed. This was true both for the water column as well as for biofilms on the surface of macrophytes or dead wood and the oxic surface layer of the sediment. Stable isotope analysis of nitrate showed (18)O values typical for nitrification only in neutral lakes. In a comparison of NH4(+) concentrations in 297 surface waters with different pH, ammonium concentrations higher 10 mg NH4-N L(-1) were only observed in lakes below pH 3. On the basis of the results from stable isotope investigations and the examination of a metadata set we conclude that the lower limit for nitrification in lakes is around pH 3.

  20. Aquatic fulvic acids in microbially based ecosystems: results from two desert lakes in Antarctica

    USGS Publications Warehouse

    McKnight, Diane M.; Aiken, G.R.; Smith, R.L.

    1991-01-01

    These lakes receive very limited input of organic material from the surrounding barren desert, but they sustain algal and bacterial populations under permanent ice cover. One lake has an extensive anoxic zone and high salinities; the other is oxic and has low salinities. Despite these differences, fulvic acids from both lakes had similar elemental compositions, carbon distributions, and amino acid contents, indicating that the chemistry of microbially derived fulvic acvids is not strongly influenced by chemical conditions in the water column. Compared to fulvic acids from other natural waters, these fulvic acids have low C:N atomic ratios (19-25) and low contents of aromatic carbons (5-7% of total carbon atoms); they are most similar to marine fulvic acids. -from Authors

  1. Biomass and production of amphipods in low alkalinity lakes affected by acid precipitation.

    PubMed

    France, R L

    1996-01-01

    Population biomass and production of the amphipod Hyalella azteca (Saussure) were found to be related to alkalinity (ranging from 0.2 to 58.1 mg liter(-1)) in 10 Canadian Shield lakes in south-central Ontario. Biomass and production of amphipods in the two lakes characterized by spring depressions of pH below 5.0 were found to be lower than those for populations inhabiting lakes that did not experience such acid pulses. The proportional biomass of amphipods in relation to the total littoral zoobenthos community was lower in lakes of low alkalinity than in circumneutral or hardwater lakes. Because production in these amphipod populations is known to depend closely on population abundance, the labour-intensive derivation of production rates yields relatively little information for biomonitoring that cannot be obtained from abundance data alone. PMID:15093505

  2. Biomass and production of amphipods in low alkalinity lakes affected by acid precipitation.

    PubMed

    France, R L

    1996-01-01

    Population biomass and production of the amphipod Hyalella azteca (Saussure) were found to be related to alkalinity (ranging from 0.2 to 58.1 mg liter(-1)) in 10 Canadian Shield lakes in south-central Ontario. Biomass and production of amphipods in the two lakes characterized by spring depressions of pH below 5.0 were found to be lower than those for populations inhabiting lakes that did not experience such acid pulses. The proportional biomass of amphipods in relation to the total littoral zoobenthos community was lower in lakes of low alkalinity than in circumneutral or hardwater lakes. Because production in these amphipod populations is known to depend closely on population abundance, the labour-intensive derivation of production rates yields relatively little information for biomonitoring that cannot be obtained from abundance data alone.

  3. Unusual Nonterrestrial L-proteinogenic Amino Acid excesses in the Tagish Lake Meteorite

    NASA Technical Reports Server (NTRS)

    Glavin, Daniel P.; Elsila, Jamie E.; Burton, Aaron S.; Callahan, Michael P.; Dworkin, Jason P.; Hilts, Robert W.; Herd, D. K.

    2012-01-01

    The distribution and isotopic and enantiomeric compositions of amino acids found in three distinct fragments of the Tagish Lake C2-type carbonaceous chondrite were investigated via liquid chromatography with fluorescence detection and time-of-flight mass spectrometry and gas chromatography isotope ratio mass spectrometry. Large L-enantiomeric excesses (L(sub ee) approximately 43-59%) of the alpha-hydrogen aspartic and glutamic amino acids were measured in Tagish Lake, whereas alanine, another alpha hydrogen protein amino acid, was found to be nearly racemic (D much approximately L) using both techniques. Carbon isotope measurements of D- and L-aspartic acid and 1)- and L-alanine in Tagish Lake fall well outside of the terrestrial range and indicate that the measured aspartic acid enantioenrichment is indigenous to the meteorite. Alternate explanations for the L-excesses of aspartic acid such as interference from other compounds present in the sample, analytical biases, or terrestrial amino acid contamination were investigated and rejected. These results can be explained by differences in the solid-solution phase behavior of aspartic acid, which can form conglomerate enantiopure solids during crystallization, and alanine, which can only form racemic crystals. Amplification of a small initial L-enantiomer excess during aqueous alteration on the meteorite parent body could have led to the large L-enrichments observed for aspartic acid and other conglomerate amino acids in Tagish Lake. The detection of non terrestrial L-proteinogenic amino acid excesses in the Tagish Lake meteorite provides support for the hypothesis that significant enantiomeric enrichments for some amino acids could form by abiotic processes prior to the emergence of life.

  4. "Hairy blobs:" microbial suspects preserved in modern and ancient extremely acid lake evaporites.

    PubMed

    Benison, Kathleen C; Jagniecki, Elliot A; Edwards, Tina B; Mormile, Melanie R; Storrie-Lombardi, Michael C

    2008-08-01

    "Hairy blobs" are unusual clumps of organic bodies and sulfate crystals that have been found in evaporite minerals grown in acid saline lakes. Here, we document modern hairy blobs in halite and gypsum from 5 modern acid saline lakes in southern Western Australia, and Permian hairy blobs trapped in halite from the mid-Permian Opeche Shale in the subsurface of North Dakota. These are among the first microbial remains described from acid saline lake environments. They give clues about the role of microorganisms in the acidity, geochemistry, and mineralogy of these extreme environments. This study also may add to the inventory of life in extreme environments and help predict possible martian life-forms and the method of preservation. PMID:18498219

  5. "Hairy blobs:" microbial suspects preserved in modern and ancient extremely acid lake evaporites.

    PubMed

    Benison, Kathleen C; Jagniecki, Elliot A; Edwards, Tina B; Mormile, Melanie R; Storrie-Lombardi, Michael C

    2008-08-01

    "Hairy blobs" are unusual clumps of organic bodies and sulfate crystals that have been found in evaporite minerals grown in acid saline lakes. Here, we document modern hairy blobs in halite and gypsum from 5 modern acid saline lakes in southern Western Australia, and Permian hairy blobs trapped in halite from the mid-Permian Opeche Shale in the subsurface of North Dakota. These are among the first microbial remains described from acid saline lake environments. They give clues about the role of microorganisms in the acidity, geochemistry, and mineralogy of these extreme environments. This study also may add to the inventory of life in extreme environments and help predict possible martian life-forms and the method of preservation.

  6. 16. Detail of drainage pits inside east half (1892 part) ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    16. Detail of drainage pits inside east half (1892 part) of main section of roundhouse. View to southeast. - Duluth & Iron Range Rail Road Company Shops, Roundhouse, Southwest of downtown Two Harbors, northwest of Agate Bay, Two Harbors, Lake County, MN

  7. Selective transfer of polyunsaturated fatty acids from phytoplankton to planktivorous fish in large boreal lakes.

    PubMed

    Strandberg, Ursula; Hiltunen, Minna; Jelkänen, Elli; Taipale, Sami J; Kainz, Martin J; Brett, Michael T; Kankaala, Paula

    2015-12-01

    Lake size influences various hydrological parameters, such as water retention time, circulation patterns and thermal stratification that can consequently affect the plankton community composition, benthic-pelagic coupling and the function of aquatic food webs. Although the socio-economical (particularly commercial fisheries) and ecological importance of large lakes has been widely acknowledged, little is known about the availability and trophic transfer of polyunsaturated fatty (PUFA) in large lakes. The objective of this study was to investigate trophic trajectories of PUFA in the pelagic food web (seston, zooplankton, and planktivorous fish) of six large boreal lakes in the Finnish Lake District. Docosahexaenoic acid (DHA), eicosapentaenoic acid (EPA) and α-linolenic acid (ALA) were the most abundant PUFA in pelagic organisms, particularly in the zooplanktivorous fish. Our results show that PUFA from the n-3 family (PUFAn-3), often associated with marine food webs, are also abundant in large lakes. The proportion of DHA increased from ~4±3% in seston to ~32±6% in vendace (Coregonus albula) and smelt (Osmerus eperlanus), whereas ALA showed the opposite trophic transfer pattern with the highest values observed in seston (~11±2%) and the lowest in the opossum shrimp (Mysis relicta) and fish (~2±1%). The dominance of diatoms and cryptophytes at the base of the food web in the study lakes accounted for the high amount of PUFAn-3 in the planktonic consumers. Furthermore, the abundance of copepods in the large lakes explains the effective transfer of DHA to planktivorous fish. The plankton community composition in these lakes supports a fishery resource (vendace) that is very high nutritional quality (in terms of EPA and DHA contents) to humans.

  8. Selective transfer of polyunsaturated fatty acids from phytoplankton to planktivorous fish in large boreal lakes.

    PubMed

    Strandberg, Ursula; Hiltunen, Minna; Jelkänen, Elli; Taipale, Sami J; Kainz, Martin J; Brett, Michael T; Kankaala, Paula

    2015-12-01

    Lake size influences various hydrological parameters, such as water retention time, circulation patterns and thermal stratification that can consequently affect the plankton community composition, benthic-pelagic coupling and the function of aquatic food webs. Although the socio-economical (particularly commercial fisheries) and ecological importance of large lakes has been widely acknowledged, little is known about the availability and trophic transfer of polyunsaturated fatty (PUFA) in large lakes. The objective of this study was to investigate trophic trajectories of PUFA in the pelagic food web (seston, zooplankton, and planktivorous fish) of six large boreal lakes in the Finnish Lake District. Docosahexaenoic acid (DHA), eicosapentaenoic acid (EPA) and α-linolenic acid (ALA) were the most abundant PUFA in pelagic organisms, particularly in the zooplanktivorous fish. Our results show that PUFA from the n-3 family (PUFAn-3), often associated with marine food webs, are also abundant in large lakes. The proportion of DHA increased from ~4±3% in seston to ~32±6% in vendace (Coregonus albula) and smelt (Osmerus eperlanus), whereas ALA showed the opposite trophic transfer pattern with the highest values observed in seston (~11±2%) and the lowest in the opossum shrimp (Mysis relicta) and fish (~2±1%). The dominance of diatoms and cryptophytes at the base of the food web in the study lakes accounted for the high amount of PUFAn-3 in the planktonic consumers. Furthermore, the abundance of copepods in the large lakes explains the effective transfer of DHA to planktivorous fish. The plankton community composition in these lakes supports a fishery resource (vendace) that is very high nutritional quality (in terms of EPA and DHA contents) to humans. PMID:26282609

  9. Lake

    ERIC Educational Resources Information Center

    Wien, Carol Anne

    2008-01-01

    The lake is blue black and deep. It is a glaciated finger lake, clawed out of rock when ice retracted across Nova Scotia in a northerly direction during the last ice age. The lake is narrow, a little over a mile long, and deep, 90 to 190 feet in places according to local lore, off the charts in others. The author loves to swim there, with a sense…

  10. Chemical and biological recovery from acid deposition within the Honnedaga Lake watershed, New York, USA.

    PubMed

    Josephson, Daniel C; Robinson, Jason M; Chiotti, Justin; Jirka, Kurt J; Kraft, Clifford E

    2014-07-01

    Honnedaga Lake in the Adirondack region of New York has sustained a heritage brook trout population despite decades of atmospheric acid deposition. Detrimental impacts from acid deposition were observed from 1920 to 1960 with the sequential loss of acid-sensitive fishes, leaving only brook trout extant in the lake. Open-lake trap net catches of brook trout declined for two decades into the late 1970s, when brook trout were considered extirpated from the lake but persisted in tributary refuges. Amendments to the Clean Air Act in 1990 mandated reductions in sulfate and nitrogen oxide emissions. By 2000, brook trout had re-colonized the lake coincident with reductions in surface-water sulfate, nitrate, and inorganic monomeric aluminum. No changes have been observed in surface-water acid-neutralizing capacity (ANC) or calcium concentration. Observed increases in chlorophyll a and decreases in water clarity reflect an increase in phytoplankton abundance. The zooplankton community exhibits low species richness, with a scarcity of acid-sensitive Daphnia and dominance by acid-tolerant copepods. Trap net surveys indicate that relative abundance of adult brook trout population has significantly increased since the 1970s. Brook trout are absent in 65 % of tributaries that are chronically acidified with ANC of <0 μeq/L and toxic aluminum levels (>2 μmol/L). Given the current conditions, a slow recovery of chemistry and biota is expected in Honnedaga Lake and its tributaries. We are exploring the potential to accelerate the recovery of brook trout abundance in Honnedaga Lake through lime applications to chronically and episodically acidified tributaries. PMID:24671614

  11. Chemical response of lakes in the Adirondack Region of New York to declines in acidic deposition.

    PubMed

    Driscoll, Charles T; Driscoll, Kimberley M; Roy, Karen M; Mitchell, Myron J

    2003-05-15

    Long-term changes in the chemistry of wet deposition and lake water were investigated in the Adirondack Region of New York. Marked decreases in concentrations of SO4(2-) and H+ in wet deposition have occurred at two sites since the late 1970s. These decreases are consistent with long-term declines in emissions of sulfur dioxide (SO2) in the eastern United States. Changes in wet NO3- deposition and nitrogen oxides (NOx) emissions have been minor over the same interval. Virtually all Adirondack Lakes have shown marked decreases in concentrations of SO4(2-), which coincide with decreases in atmospheric S deposition. Concentrations of NO3- have also decreased in several Adirondack lakes. As atmospheric N deposition has not changed over this period, the mechanism contributing to this apparent increase in lake/watershed N retention is not evident. Decreases in concentrations of SO4(2-) + NO3- have resulted in increases in acid-neutralizing capacity (ANC) and pH and resulted in a shift in the speciation of monomeric Al from toxic inorganic species toward less toxic organic forms in some lakes. Nevertheless, many lakes continue to exhibit pH values and concentrations of inorganic monomeric Al that are critical to aquatic biota. Extrapolation of rates of ANC increase suggests that the time frame of chemical recovery of Adirondack Lakes will be several decades if current decreases in acidic deposition are maintained.

  12. Fish population losses from Adirondack Lakes: The role of surface water acidity and acidification

    NASA Astrophysics Data System (ADS)

    Baker, Joan P.; Warren-Hicks, William J.; Gallagher, James; Christensen, Sigurd W.

    1993-04-01

    Changes over time in the species composition of fish communities in Adirondack lakes were assessed to determine (1) the approximate numbers offish populations that have been lost and (2) the degree to which fish population losses may have resulted from surface water acidification and acidic deposition. Information on the present-day status offish communities was obtained by the Adirondack Lakes Survey Corporation, which surveyed 1469 Adirondack lakes in 1984-1987 (53% of the total ponded waters in the Adirondack ecological zone). Two hundred and ninety-five of these lakes had been surveyed in 1929-1934 during the first statewide biological survey; 720 had been surveyed in one or more years prior to 1970. Sixteen to 19% of the lakes with adequate historical data appeared to have lost one or more fish populations as a result of acidification. Brook trout and acid-sensitive minnow species had experienced the most widespread effects. Populations of brook trout and acid-sensitive minnows had been lost apparently as a result of acidification from 11% and 19%, respectively, of the lakes with confirmed historical occurrence of these taxa. By contrast, fish species that tend to occur primarily in lower elevation and larger lakes, such as largemouth and smallmouth bass and brown trout, have experienced little to no documented adverse effects. Lakes that were judged to have lost fish populations as a result of acidification had significantly lower; pH and, in most cases, also had higher estimated concentrations of inorganic aluminum and occurred at higher elevations than did lakes with the fish species still present. No other lake characteristics were consistently associated with fish population losses attributed to acidification. The exact numbers and proportions of fish populations affected could not be determined because of limitations on the quantity and quality of historical data. Lakes for which we had adequate historical data to assess long-term trends in fish

  13. Species diversity of fishes in naturally acidic lakes in New Jersey

    SciTech Connect

    Graham, J.H. )

    1993-11-01

    Fish communities in acidic lakes of New Jersey have fewer species than do those in more alkaline lakes of comparable size. This conclusion is based on a multiple regression analysis of published data on fish communities, area, and pH in 85 lakes. Some interesting patterns emerge, however, when species are partitioned into introduced and native species. As expected, diversity of introduced species declines with increasing acidity. The number of native species in a particular lake, however, is independent of pH (range of 4.1 to 9.1). Although diversity of native species is not influenced by pH, species composition changes. The lack of a significant relationship between species diversity of native species and pH can be attributed to the replacement of acid-intolerant species by tolerant species. The smaller number of introduced species in acidic lakes is attributable to both fewer species stocked and a greater frequency of failure for those that were stocked. Species introduction records for largemouth bass Micropterus salmoides and bluegill Lepomis macrochirus, which are not native to New Jersey, reveal far more failed introduction in acidic waters than in neutral or alkaline waters. 54 refs., 6 figs., 5 tabs.

  14. Assessment of acidity of lakes and precipitation in the Sierra Nevada

    SciTech Connect

    Melack, J.M.

    1983-06-01

    The east central Sierra Nevada received acid precipitation (pH 3.7 to 4.9) during the convective storms interspersed through the dry seasons of 1981 and 1982. In contrast, late autumn, winter and early spring snow (1981-1982) ranged in pH from 5.2 to 6.1 (mean 5.7) and had low ammonium, nitrate and sulfate concentrations. As of 1981 most of the alpine lakes of the Sierra Nevada remain very weakly buffered, bicarbonate lakes that receive a small loading of acid precipitation and a large annual input of snowmelt uncontaminated by strong acids. These lakes contain low concentrations of orthophosphate, nitrate and ammonium and are oligotrophic. The zooplankton communities fall into two major groups, those dominated by large-bodied species in the absence of fish, and those dominated by smaller species where fish are present. If the acidity of the precipitation increases the pH of the lakes will decrease rapidly with adverse biological impacts because the lakes and their basins have extremely low buffer capacity and the biota cannot tolerate acidic water. 65 references, 14 figures, 6 tables.

  15. Changes in acid precipitation-related water chemistry of lakes from southwestern New Brunswick, Canada, 1986-2001.

    PubMed

    Pilgrim, W; Clair, T A; Choate, J; Hughes, R

    2003-01-01

    Between 1986 and 2001, thirty-nine lakes in southwestern New Brunswick in Atlantic Canada were surveyed for acid precipitation-related water quality changes. Most of the study lakes are located on granite bedrock and represent the most acid sensitive lakes in the province. Between 1987 and 1992, hydrogen ion deposition to the lake study area averaged 452 eq ha(-1) yr(-1), compared to 338 eq ha(-1) yr(-1) between 1993 and 2000, a 25% reduction. The lake chemistry data were evaluated by dividing the lakes into four clusters for each survey year based on their acid neutralizing capacity. Twenty percent of the lakes (cluster IV) had an average ANC of 40 microeq L(-1) or greater and maintained an average pH of greater than 6 over the duration of the study period. A pH of 6 or greater is considered a healthy benchmark for maintaining biodiversity. The remaining 31 lakes (clusters I to III) had an average ANC of less than 40 microeq L(-1) and maintained an average pH of less than 6. Other lake chemistry changes included a general decline in lake sulphate and colour over the duration of the survey period, followed by more recent improvements in calcium ion, pH and ANC, and notably higher but declining aluminum levels in lower ANC and pH lakes. Nitrate accounted for 37% of the acid deposition to the study area, however it was not detectable in the lakes. Although acid deposition has declined and these lakes are beginning to show signs of acid recovery, 80% of the study lakes remain acid sensitive having little buffering capacity with low calcium, pH and ANC.

  16. Generation of Acid Mine Lakes Associated with Abandoned Coal Mines in Northwest Turkey.

    PubMed

    Sanliyuksel Yucel, Deniz; Balci, Nurgul; Baba, Alper

    2016-05-01

    A total of five acid mine lakes (AMLs) located in northwest Turkey were investigated using combined isotope, molecular, and geochemical techniques to identify geochemical processes controlling and promoting acid formation. All of the investigated lakes showed typical characteristics of an AML with low pH (2.59-3.79) and high electrical conductivity values (1040-6430 μS/cm), in addition to high sulfate (594-5370 mg/l) and metal (aluminum [Al], iron [Fe], manganese [Mn], nickel [Ni], and zinc [Zn]) concentrations. Geochemical and isotope results showed that the acid-generation mechanism and source of sulfate in the lakes can change and depends on the age of the lakes. In the relatively older lakes (AMLs 1 through 3), biogeochemical Fe cycles seem to be the dominant process controlling metal concentration and pH of the water unlike in the younger lakes (AMLs 4 and 5). Bacterial species determined in an older lake (AML 2) indicate that biological oxidation and reduction of Fe and S are the dominant processes in the lakes. Furthermore, O and S isotopes of sulfate indicate that sulfate in the older mine lakes may be a product of much more complex oxidation/dissolution reactions. However, the major source of sulfate in the younger mine lakes is in situ pyrite oxidation catalyzed by Fe(III) produced by way of oxidation of Fe(II). Consistent with this, insignificant fractionation between δ(34) [Formula: see text] and δ(34) [Formula: see text] values indicated that the oxidation of pyrite, along with dissolution and precipitation reactions of Fe(III) minerals, is the main reason for acid formation in the region. Overall, the results showed that acid generation during early stage formation of an AML associated with pyrite-rich mine waste is primarily controlled by the oxidation of pyrite with Fe cycles becoming the dominant processes regulating pH and metal cycles in the later stages of mine lake development. PMID:26987541

  17. Polymethylene-interrupted fatty acids: Biomarkers for native and exotic mussels in the Laurentian Great Lakes

    USGS Publications Warehouse

    Mezek, Tadej; Sverko, Ed; Ruddy, Martina D.; Zaruk, Donna; Capretta, Alfredo; Hebert, Craig E.; Fisk, Aaron T.; McGoldrick, Daryl J.; Newton, Teresa J.; Sutton, Trent M.; Koops, Marten A.; Muir, Andrew M.; Johnson, Timothy B.; Ebener, Mark P.; Arts, Michael T.

    2011-01-01

    Freshwater organisms synthesize a wide variety of fatty acids (FAs); however, the ability to synthesize and/or subsequently modify a particular FA is not universal, making it possible to use certain FAs as biomarkers. Herein we document the occurrence of unusual FAs (polymethylene-interrupted fatty acids; PMI-FAs) in select freshwater organisms in the Laurentian Great Lakes. We did not detect PMI-FAs in: (a) natural seston from Lake Erie and Hamilton Harbor (Lake Ontario), (b) various species of laboratory-cultured algae including a green alga (Scenedesmus obliquus), two cyanobacteria (Aphanizomenon flos-aquae and Synechococystis sp.), two diatoms (Asterionella formosa, Diatoma elongatum) and a chrysophyte (Dinobryon cylindricum) or, (c) zooplankton (Daphnia spp., calanoid or cyclopoid copepods) from Lake Ontario, suggesting that PMI-FAs are not substantively incorporated into consumers at the phytoplankton–zooplankton interface. However, these unusual FAs comprised 4-6% of total fatty acids (on a dry tissue weight basis) of native fat mucket (Lampsilis siliquoidea) and plain pocketbook (L. cardium) mussels and in invasive zebra (Dreissena polymorpha) and quagga (D. bugensis) mussels. We were able to clearly partition Great Lakes' mussels into three separate groups (zebra, quagga, and native mussels) based solely on their PMI-FA profiles. We also provide evidence for the trophic transfer of PMI-FAs from mussels to various fishes in Lakes Ontario and Michigan, further underlining the potential usefulness of PMI-FAs for tracking the dietary contribution of mollusks in food web and contaminant-fate studies.

  18. Variation in Lake Michigan alewife (Alosa pseudoharengus) thiaminase and fatty acids composition

    USGS Publications Warehouse

    Honeyfield, D.C.; Tillitt, D.E.; Fitzsimons, J.D.; Brown, S.B.

    2010-01-01

    Thiaminase activity of alewife (Alosa pseudoharengus) is variable across Lake Michigan, yet factors that contribute to the variability in alewife thiaminase activity are unknown. The fatty acid content of Lake Michigan alewife has not been previously reported. Analysis of 53 Lake Michigan alewives found a positive correlation between thiaminase activity and the following fatty acid: C22:ln9, sum of omega-6 fatty acids (Sw6), and sum of the polyunsaturated fatty acids. Thiaminase activity was negatively correlated with C15:0, C16:0, C17:0, C18:0, C20:0, C22:0, C24:0, C18:ln9t, C20:3n3, C22:2, and the sum of all saturated fatty acids (SAFA). Multi-variant regression analysis resulted in three variables (C18:ln9t, Sw6, SAFA) that explained 71% (R2=0.71, P<0.0001) of the variation in thiaminase activity. Because the fatty acid content of an organism is related is food source, diet may be an important factor modulating alewife thiaminase activity. These data suggest there is an association between fatty acids and thiaminase activity in Lake Michigan alewife.

  19. Chemical and biological status of lakes and streams in the upper midwest: assessment of acidic deposition effects

    USGS Publications Warehouse

    Wiener, J.G.; Eilers, J.M.

    1987-01-01

    Many lakes in three areas in the Upper Midwest - northeastern Minnesota, northern Wisconsin, and the Upper Peninsula of Michigan - have low acid neutralizing capacity (ANC) and may be susceptible to change by acidic deposition. Northcentral Wisconsin and the Upper Peninsula of Michigan together contain about 150-300 acidic lakes (ANC ≤ 0), whereas none have been found in Minnesota. These acidic lakes are precipitation-dominated, Clearwater seepage lakes having small surface area, shallow depth, and low concentrations of dissolved organic carbon. The spatial distribution of these acidic lakes parallels a west to east gradient of increasing sulfate and hydrogen ion deposition. Several of these acidic lakes exhibit chemical characteristics and biological changes consistent with those observed elsewhere in waters reported to be acidified by acidic deposition. However, an hypothesis of recent lake acidification is not supported by analyses of either historical chemical data or diatom remains in lake sediments, and natural sources of acidity and alternative ecological processes have not been conclusively eliminated as causative factors. Streams in this three-state region have high ANC and appear to be insensitive to acidic deposition. The species richness and composition of lacustrine fish communities in the region are partly related to pH and associated chemical factors. Sport fishes considered acid-sensitive and of primary concern with regard to acidification include walleye, smallmouth bass, and black crappie. The fishery in at least one lake, Morgan Lake in Wisconsin (pH 4.6), may have declined because of acidification. Given the general lack of quantitative fishery data for acidic Wisconsin and Michigan lakes, however, more general conclusions concerning impacts or the absence of impacts of acidification on the region's fishery resources are not possible.

  20. Integrated Lake-Watershed Acidification Study (ILWAS): contributions to the international conference on the ecological impact of acid precipitation

    SciTech Connect

    Not Available

    1981-05-01

    The Integrated Lake-Watershed Acidification Study (ILWAS) was initiated to study and detail lake acidification processes for three lake watershed basins in the Adirondack Park region of New York. The three basins (Woods, Sagamore, and Panther), receive similar amounts of acid deposition yet observable pH values for the lakes are very dissimilar indicating unequal acid neutralizing capacities among the watersheds. This volume contains a compilation of seven papers. Relevant topics include: a characterization of the geology, hydrology, limnology and vegetation of the three study sites, an analysis of acid precipitation quality and quantity, the effects of vegetative canopy, the effects of snowmelt, the effects of winter lake stratification, comparison of heavy metal transport, examination of acidic sources other than direct precipitation, assessment of lake acidification during spring thaw and integration of all acidification components with a mathematical model.

  1. Decision Document for the Storm Water Outfalls/Industrial Wastewater Treatment Plant, Pesticide Rinse Area, Old Fire Fighting Training Pit, Illicit PCB Dump Site, and the Battery Acid Pit Fort Lewis, Washington

    SciTech Connect

    Cantrell, Kirk J.; Liikala, Terry L.; Strenge, Dennis L.; Taira, Randal Y.

    2000-12-11

    PNNL conducted independent site evaluations for four sites at Fort Lewis, Washington, to determine their suitability for closure on behalf of the installation. These sites were recommended for "No Further Action" by previous invesitgators and included the Storm Water Outfalls/Industrial Waste Water Treatment Plant (IWTP), the Pesticide Rinse Area, the Old Fire Fighting Training Pit, and the Illicit PCB Dump Site.

  2. Decision Document for the Storm Water Outfalls/Industrial Wastewater Treatment Plant, Pesticide Rinse Area, Old Fire Fighting Training Pit, Illicit PCB Dump Site, and the Battery Acid Pit Fort Lewis, Washington

    SciTech Connect

    Cantrell, Kirk J; Liikala, Terry L; Strenge, Dennis L; Taira, Randal Y

    2001-01-10

    PNNL conducted independent site evaluations for four sites at Fort Lewis, Washington, to determine their suitability for closure on behalf of the installation. These sites were recommended for ''No Further Action'' by previous investigators and included the Storm Water Outfalls/Industrial Waste Water Treatment Plant (IWTP), the Pesticide Rinse Area, the Old Fire Fighting Training Pit, and the Illicit PCB Dump Site.

  3. Evaluating long-term trends in littoral benthic macroinvertebrate communities of lakes recovering from acid deposition.

    PubMed

    Lento, Jennifer; Dillon, Peter J; Somers, Keith M

    2012-12-01

    The Mann-Kendall test has been proposed as a nonparametric method to evaluate trends in long-term water quality datasets with missing values, serial correlation, and non-normality. However, this test has rarely been used to evaluate long-term trends in biological data. In this study, we used the Mann-Kendall test to evaluate trends in 15 years of data on benthic macroinvertebrate communities from 17 Precambrian Shield lakes. We also used the van Belle and Hughes test of trend homogeneity to assess whether common among-lake temporal trends existed. We assumed that evidence of a common regional trend among lakes would support the hypothesis of long-term biological recovery from past acidification. We found decreasing proportions of Chironomidae and increasing proportions of Ephemeroptera, Plecoptera, and Trichoptera (EPT) in both single-lake and multi-lake trend analysis. Moreover, six of the nine lakes with significant trends in more than one benthos metric displayed a significant decrease in Chironomidae and increase in EPT concurrently, indicating a shift towards more acid-sensitive taxa. Weak trends in several of the biological metrics indicated that recovery in these lakes has been impeded. Results of this study indicate that the Mann-Kendall and van Belle and Hughes trend tests are useful statistical tools to evaluate long-term patterns in biological data.

  4. Evaluating long-term trends in littoral benthic macroinvertebrate communities of lakes recovering from acid deposition.

    PubMed

    Lento, Jennifer; Dillon, Peter J; Somers, Keith M

    2012-12-01

    The Mann-Kendall test has been proposed as a nonparametric method to evaluate trends in long-term water quality datasets with missing values, serial correlation, and non-normality. However, this test has rarely been used to evaluate long-term trends in biological data. In this study, we used the Mann-Kendall test to evaluate trends in 15 years of data on benthic macroinvertebrate communities from 17 Precambrian Shield lakes. We also used the van Belle and Hughes test of trend homogeneity to assess whether common among-lake temporal trends existed. We assumed that evidence of a common regional trend among lakes would support the hypothesis of long-term biological recovery from past acidification. We found decreasing proportions of Chironomidae and increasing proportions of Ephemeroptera, Plecoptera, and Trichoptera (EPT) in both single-lake and multi-lake trend analysis. Moreover, six of the nine lakes with significant trends in more than one benthos metric displayed a significant decrease in Chironomidae and increase in EPT concurrently, indicating a shift towards more acid-sensitive taxa. Weak trends in several of the biological metrics indicated that recovery in these lakes has been impeded. Results of this study indicate that the Mann-Kendall and van Belle and Hughes trend tests are useful statistical tools to evaluate long-term patterns in biological data. PMID:22193633

  5. Estimation of critical loads of acidity for lakes in northeastern United States and eastern Canada.

    PubMed

    Dupont, J; Clair, T A; Gagnon, C; Jeffries, D S; Kahl, J S; Nelson, S J; Peckenham, J M

    2005-10-01

    The New England Governors and Eastern Canadian Premiers (NEG/ECP) adopted the Acid Rain Action Plan in June 1998, and issued a series of action items to support its work toward a reduction of sulfur dioxide (SO(2)) and nitrogen oxide (NO(x)) emissions in northeastern North America. One of these action items was the preparation of an updated critical load map using data from lakes in the NEG/ECP area. Critical load maps provide a more complete index of the surface water sensitivity to acidification. Combined sulfur and nitrogen critical loads and deposition exceedances were computed using Henriksen's Steady-State Water Chemistry (SSWC) model. Results show that 28% of all 2053 lakes studied have a critical load of 20 kg/ha/year or less, making them vulnerable to acid deposition. Emission reductions, and more specifically SO(2) emission reductions have proven beneficial because critical loads were exceeded in 2002 for 12.3% of all studied lakes. Those lakes are located in the more sensitive areas where geology is carbonate-poor. Of these lakes, 2.9% will never recover even with a complete removal of SO(4) deposition. Recovery from acidification for the remaining 9.4% of the lakes will require additional emission SO(2) reductions.

  6. Stable carbon and nitrogen isotopes and amino acids in Holocene sediments of Lake Lonar, central India

    NASA Astrophysics Data System (ADS)

    Menzel, Philip; Gaye, Birgit; Wiesner, Martin; Basavaiah, Nathani; Prasad, Sushma; Stebich, Martina; Anoop, Ambili; Riedel, Nils

    2013-04-01

    Investigations on surface sediments and a sediment core from Lake Lonar in central India were carried out within the framework of the HIMPAC (Himalaya: Modern and Past Climate) programme. The aim was to understand recent productivity, sedimentation, and degradation processes and to reconstruct variations in Holocene lake conditions on the basis of biogeochemical analysis on a 10 m long sediment core retrieved from the centre of Lake Lonar. Located in India's core monsoon zone, Lake Lonar offers valuable information about the climate development of the whole region. The lake is situated at the floor of a meteorite impact structure on the Deccan plateau basalt. The modern lake is characterised by brackish water, high alkalinity, severe eutrophication, and bottom water anoxia. The lake is about 6 m deep and fed by rainfall during the SW monsoon season and three perennial streams. Since no out-flowing stream is present and no seepage loss occurs, the lake level is highly sensitive to the balance of precipitation and evaporation. Here we present C/N, carbon and nitrogen isotope, and amino acid data of bulk organic matter from modern lake and Holocene core sediments. Modern conditions are mainly related to human activity which started to have persistent influence on the biological and chemical lake properties at ~1200 cal a BP. The distribution of δ13C in the modern sediments is driven by the ratio between terrestrial and aquatic organic matter, while δ15N seems to be influenced by redox conditions at the sediment-water-interface with elevated values at shallow oxic stations. Differences in the amino acid assemblages of oxic and anoxic surface sediment samples were used to calculate an Ox/Anox ratio indicating the redox conditions during organic matter degradation. The onset of the monsoon reconstructed from the sediment core occurred at ca. 11450 cal a BP. The early Holocene core sediments are characterised by low sedimentation rate, low aquatic productivity, and

  7. Analysis of southeastern Canada lake-water chemistry data in relation to acidic deposition

    SciTech Connect

    Olson, R.J.; Cook, R.B.; Ross-Todd, B.M.; Beauchamp, J.J.

    1990-05-01

    Lake-water chemistry data were obtained for lakes in southeastern Canada to study relationships between atmospheric deposition and acid-base chemistry as part of the National Acid Precipitation Assessment Program State of Science and Technology reports. Quality assurance checks were made to ensure that the data used were of sufficient quality and were comparable to data from the United States. Ninety-eight percent of the 8506 sampled lakes had pH, ANC, and SO{sub 4}{sup 2 {minus}} data and were used in our analyses. Of these, we created a subset of 4017 lakes having data for more variable (Ca{sup 2+}, Mg{sup 2+}, Na{sup +}, K{sup +}, DOC, and conductivity) to analyze potential sources of lake-water acidity. The objectives of this work were to determine the geographical extent and number of potentially affected systems and to infer causes of acidification based on ion ratios. 35 refs., 28 figs., 12 tabs.

  8. Spatial characterization of acid rain stress in Canadian Shield Lakes

    NASA Technical Reports Server (NTRS)

    Tanis, Fred J.

    1987-01-01

    An analysis was performed to interpret the spatial aspects of lake acidification. Three types of relationships were investigated based upon the August to May seasonal scene pairing. In the first type of analysis ANOVA was used to examine the mean Thematic Mapper band one count by ecophysical strata. The primary difference in the two ecophysical strata is the soil type and depth over the underlying bedrock. Examination of the August to May difference values for TM band one produced similar results. Group A and B strata were the same as above. The third type of analysis examined the relationship between values of the August to May difference from polygons which have similar ecophysical properties with the exception of sulfate deposition. For this case lakes were selected from units with sandy soils over granitic rock types and the sulfate deposition was 1.5 or 2.5 g/sq m/yr.

  9. Impacts on water quality and biota from natural acid rock drainage in Colorado's Lake Creek watershed

    USGS Publications Warehouse

    Bird, D.A.; Sares, Matthew A.; Policky, Greg A.; Schmidt, Travis S.; Church, Stanley E.

    2006-01-01

    Colorado's Lake Creek watershed hosts natural acid rock drainage that significantly impacts surface water, streambed sediment, and aquatic life. The source of the ARD is a group of iron-rich springs that emerge from intensely hydrothermally altered, unexploited, low-grade porphyry copper mineralization in the Grizzly Peak Caldera. Source water chemistry includes pH of 2.5 and dissolved metal concentrations of up to 277 mg/L aluminum, 498 mg/L iron, and 10 mg/L copper. From the hydrothermally altered area downstream for 27 kilometers to Twin Lakes Reservoir, metal concentrations in streambed sediment are elevated and the watershed experiences locally severe adverse impacts to aquatic life due to the acidic, metal-laden water. The water and sediment quality of Twin Lakes Reservoir is sufficiently improved that the reservoir supports a trout fishery, and remnants of upstream ARD are negligible.

  10. Response of DOC in acid-sensitive Maine lakes to decreasing sulfur deposition (1993 - 2009)

    EPA Science Inventory

    In response to the Clean Air Act Amendments of 1990, sulfur deposition has decreased across the northeastern United States. As a result, sulfate concentrations in lakes and streams have also decreased and many surface waters have become less acidic. Over the same time period, th...

  11. Recolonization of acid-damaged lakes by the benthic invertebrates Stenacron interpunctatum, Stenonema femoratum and Hyalella azteca.

    PubMed

    Snucins, Ed

    2003-04-01

    The recolonization of acid-damaged lakes in Killarney Park, Canada is described for 3 species of benthic invertebrates; 2 mayflies (Stenonema femoratum, Stenacron interpunctatum) and an amphipod (Hyalella azteca). Synoptic surveys of 119 lakes for amphipods and 77 lakes for mayflies were conducted between 1995 and 1997 and defined pH thresholds of 5.6 for S. femoratum and H. azteca and pH 5.3 for S. interpunctatum. In an intensive study of 2 acid-damaged lakes and 2 reference lakes from 1997 to 2002, reestablishment of S. interpunctatum, S. femoratum and H. azteca occurred, when timing of the events could be estimated, less than 4-8 years after pH thresholds for specific taxa were reached. Dispersal of S. interpunctatum to all habitat patches within a lake was completed 3 years after recolonization was detected in the smallest lake (11 ha). It is anticipated that dispersal throughout the largest lake (189 ha) will take much longer. The time lag from estimated pH recovery to reestablishment and subsequent dispersal of mayflies to all suitable habitats within a lake was as much as 11 to 22+ years. The density of S. interpunctatum increased in the recovering lakes to levels higher than in reference lakes, but stable endpoints have not yet been reached during 6 years of monitoring.

  12. Decreased acid deposition and the chemical recovery of Killarney, Ontario, lakes.

    PubMed

    Keller, Wendel; Heneberry, Jocelyne H; Dixit, Sushil S

    2003-04-01

    Lakes in Killarney Park near Sudbury, Ontario, Canada, have shown dramatic water quality changes including general increases in pH and alkalinity, and decreases in SO4(2-), base cations and metals. While some lakes have recovered to pH > 6.0, many are still highly acidic despite decades of improvement. Very high historical S deposition related to emissions from the Sudbury metal smelters dominated the acidification process in this region. However, since the implementation of substantial S emission controls (90%) at the smelters, the Sudbury emissions are no longer the major source of S deposition in the Sudbury area. Wet deposition of SO4(2-) and SO4(2-) concentrations in lakewaters at Killarney now approach values in the Dorset, Ontario, area, about 200 km from Sudbury. This suggests that the S deposition to the Killarney area is now primarily from long-range transport, not from local sources. Studies of Killarney lakes are revealing the complex nature of the chemical recovery process. As lake acidity decreases, other changes including decreased Ca2+ concentrations, increased transparency, and altered thermal regimes may potentially affect some of these ecosystems. It is clear that continuing assessments of the recovery of Killarney lakes, within a multiple-stressor framework, are needed.

  13. Effects of acidic lake water on the eye.

    PubMed

    Basu, P K; Avaria, M; Hasany, S M

    1982-04-01

    The normal eyes of 6 men and 21 rabbits were exposed to samples of lake water, one eye to a sample of pH 4.6 and the other to a sample of pH 6.3. The men's eyes were exposed for 5 minutes on four occasions a week apart, whereas the rabbits' eyes were exposed for 15 minutes either on one occasion or once a day for 7 days. In the humans neither sample of water produced symptoms or signs of an adverse effect on the external eye tissues, apart from brief conjunctival congestion after every exposure. In the rabbits the two samples did not appear, in general, to have different effects on the ocular tissues, as judged from the osmolarity and cell count of the tears, conjunctival congestion, corneal staining with fluorescein, corneal permeability and histologic features of the cornea. In a few instances differences were observed, but their pathological significance was not apparent. These data suggest that lake water of a pH as low as 4.6 may not harm healthy eyes, however, larger and broader studies are essential.

  14. Fish communities in lakes in Subregion 2B (Upper Peninsula of Michigan) in relation to lake acidity. Volume 1 and Volume 2: Appendices. Data tape documentation

    SciTech Connect

    Not Available

    1990-10-01

    The research described in the document represents one component of Phase II of the Eastern Lake Survey (ELS-II), a part of the National Surface Water Survey (NSWS). Surveys of fish community status were conducted in summer 1987 in 49 lakes in ELS Subregion 2B, the Upper Peninsula of Michigan. Subregion 2B was selected because of its (1) high proportion of acidic and low-pH lakes, (2) relative lack of existin data on fish communities in lakes, and (3) diverse geological and hydrological conditions allowing optimal evaluation of the association between lake characteristics and fish community status. A companion study dealing with regional patterns in fish mercury content in Subregion 2B was conducted concurrently; results from the study will be presented in a subsequent report.

  15. Neutralization of an acidic surface mine lake using organic additives. Final research report, 1 July 1991-1 October 1993

    SciTech Connect

    Brugam, R.B.

    1993-10-01

    We added 9.1 metric tons of manure to a pH 2.9 acid coal mine lake in Southern Illinois to test whether the added organic matter would support sulfate and iron reduction by anaerobic bacteria resulting in the production of alkalinity and a rise in pH. The added organic matter did cause a rise in pH in the deep water of the lake, but the effect did not increase the pH of the whole lake. Experiments in laboratory microcosms at 23 C show that lake sediment treated with manure can permanently raise the pH of acid mine drainage. In the open lake diffusion of oxygen into the anaerobic zones of the water column and low water temperatures in the winter limited the effects of sulfate and iron reduction to the deep water of the lake during summer thermal stratification.

  16. Granite weathering and the sensitivity of alpine lakes to acid deposition

    SciTech Connect

    Stauffer, R.E.

    1990-07-01

    Lake chemical data from the National Surface Water Survey (NSWS) were corrected for the effects of regional atmospheric deposition and then used to evaluate the role of weathering in supplying base cations, silica, sulfate, and alkalinity to surface waters in alpine vs. subalpine, and in glaciated vs. unglaciated granitic terrane of the western and southeastern US. Thermodynamic models, idealized reaction stoichiometry, and multivariate regression involving solutes and geographic variables indicate that irreversible weathering can largely account for lake chemistry. By contrast, relatively minor roles are played by reversible ion exchange in soils and sediments, terrestrial bioaccumulation, and transformation in lakes. The regional patterns in lake acidity components (NO{sub 3}, SO{sub 4}, DOC, CO{sub 2}), and statistical relationships between acidity and base cations demonstrate that rock weathering is limited by acid inputs in many alpine catchments prior to fall overturn. The empirical success of the Henriksen alkalinity model depends on a high Ca: Na weathering ration. The latter increase with increasing physical disturbance of the catchment (juvenility), hence under natural circumstances attains a maximum as a result of on-going or recent glaciation. The Henriksen model fails in geochemically old terrane, where cation losses accompanying silicate weathering attain steady state proportions.

  17. Modeling aluminum-silicon chemistries and application to Australian acidic playa lakes as analogues for Mars

    NASA Astrophysics Data System (ADS)

    Marion, G. M.; Crowley, J. K.; Thomson, B. J.; Kargel, J. S.; Bridges, N. T.; Hook, S. J.; Baldridge, A.; Brown, A. J.; Ribeiro da Luz, B.; de Souza Filho, C. R.

    2009-06-01

    Recent Mars missions have stimulated considerable thinking about the surficial geochemical evolution of Mars. Among the major relevant findings are the presence in Meridiani Planum sediments of the mineral jarosite (a ferric sulfate salt) and related minerals that require formation from an acid-salt brine and oxidizing environment. Similar mineralogies have been observed in acidic saline lake sediments in Western Australia (WA), and these lakes have been proposed as analogues for acidic sedimentary environments on Mars. The prior version of the equilibrium chemical thermodynamic FREZCHEM model lacked Al and Si chemistries that are needed to appropriately model acidic aqueous geochemistries on Earth and Mars. The objectives of this work were to (1) add Al and Si chemistries to the FREZCHEM model, (2) extend these chemistries to low temperatures (<0 °C), if possible, and (3) use the reformulated model to investigate parallels in the mineral precipitation behavior of acidic Australian lakes and hypothetical Martian brines. FREZCHEM is an equilibrium chemical thermodynamic model parameterized for concentrated electrolyte solutions using the Pitzer approach for the temperature range from <-70 to 25 °C and the pressure range from 1 to 1000 bars. Aluminum chloride and sulfate mineral parameterizations were based on experimental data. Aluminum hydroxide and silicon mineral parameterizations were based on Gibbs free energy and enthalpy data. New aluminum and silicon parameterizations added 12 new aluminum/silicon minerals to this Na-K-Mg-Ca-Fe(II)-Fe(III)-Al-H-Cl-Br-SO 4-NO 3-OH-HCO 3-CO 3-CO 2-O 2-CH 4-Si-H 2O system that now contain 95 solid phases. There were similarities, differences, and uncertainties between Australian acidic, saline playa lakes and waters that likely led to the Burns formation salt accumulations on Mars. Both systems are similar in that they are dominated by (1) acidic, saline ground waters and sediments, (2) Ca and/or Mg sulfates, and (3) iron

  18. Modeling aluminum-silicon chemistries and application to Australian acidic playa lakes as analogues for Mars

    USGS Publications Warehouse

    Marion, G.M.; Crowley, J.K.; Thomson, B.J.; Kargel, J.S.; Bridges, N.T.; Hook, S.J.; Baldridge, A.; Brown, A.J.; Ribeiro da Luz, B.; de Souza, Filho C.R.

    2009-01-01

    Recent Mars missions have stimulated considerable thinking about the surficial geochemical evolution of Mars. Among the major relevant findings are the presence in Meridiani Planum sediments of the mineral jarosite (a ferric sulfate salt) and related minerals that require formation from an acid-salt brine and oxidizing environment. Similar mineralogies have been observed in acidic saline lake sediments in Western Australia (WA), and these lakes have been proposed as analogues for acidic sedimentary environments on Mars. The prior version of the equilibrium chemical thermodynamic FREZCHEM model lacked Al and Si chemistries that are needed to appropriately model acidic aqueous geochemistries on Earth and Mars. The objectives of this work were to (1) add Al and Si chemistries to the FREZCHEM model, (2) extend these chemistries to low temperatures (<0 ??C), if possible, and (3) use the reformulated model to investigate parallels in the mineral precipitation behavior of acidic Australian lakes and hypothetical Martian brines. FREZCHEM is an equilibrium chemical thermodynamic model parameterized for concentrated electrolyte solutions using the Pitzer approach for the temperature range from <-70 to 25 ??C and the pressure range from 1 to 1000 bars. Aluminum chloride and sulfate mineral parameterizations were based on experimental data. Aluminum hydroxide and silicon mineral parameterizations were based on Gibbs free energy and enthalpy data. New aluminum and silicon parameterizations added 12 new aluminum/silicon minerals to this Na-K-Mg-Ca-Fe(II)-Fe(III)-Al-H-Cl-Br-SO4-NO3-OH-HCO3-CO3-CO2-O2-CH4-Si-H2O system that now contain 95 solid phases. There were similarities, differences, and uncertainties between Australian acidic, saline playa lakes and waters that likely led to the Burns formation salt accumulations on Mars. Both systems are similar in that they are dominated by (1) acidic, saline ground waters and sediments, (2) Ca and/or Mg sulfates, and (3) iron

  19. 2005 Crater Lake Formation, Lahar, Acidic Flood, and Gas Emission From Chiginagak Volcano, Alaska

    NASA Astrophysics Data System (ADS)

    Schaefer, J. R.; Scott, W. E.; McGimsey, R. G.; Jorgenson, J.

    2005-12-01

    A 400-m-wide crater lake developed in the formerly snow-and-ice-filled crater of Mount Chiginagak volcano sometime between August 2004 and June 2005, presumably due to increased heat flux from the hydrothermal system. We are also evaluating the possible role of magma intrusion and degassing. In early summer 2005, clay-rich debris and an estimated 5.6 million cubic meters of acidic water from the crater exited through tunnels in the base of a glacier that breaches the south crater rim. Over 27 kilometers downstream, the acidic waters of the flood reached approximately 1.5 meters above current water levels and inundated an important salmon spawning drainage, acidifying at least the surface water of Mother Goose Lake (approximately 1 cubic kilometer in volume) and preventing the annual salmon run. No measurements of pH were taken until late August 2005. At that time the pH of water sampled from the Mother Goose Lake inlet, lake surface, and outlet stream (King Salmon River) was 3.2. Defoliation and leaf damage of vegetation along affected streams, in areas to heights of over 70 meters in elevation above flood level, indicates that a cloud of detrimental gas or aerosol accompanied the flood waters. Analysis of stream water, lake water, and vegetation samples is underway to better determine the agent responsible for the plant damage. This intriguing pattern of gas-damaged vegetation concentrated along and above the flood channels is cause for further investigation into potential hazards associated with Chiginagak's active crater lake. Anecdotal evidence from local lodge owners and aerial photographs from 1953 suggest that similar releases occurred in the mid-1970s and early 1950s.

  20. Cloning of the full length pig PIT1 (POU1F1) CDNA and a novel alternative PIT1 transcript, and functional studies of their encoded proteins.

    PubMed

    Yu, T P; Sun, H S; Wahls, S; Sanchez-Serrano, I; Rothschild, M F; Tuggle, C K

    2001-05-01

    PIT1 is an essential regulatory gene of growth hormone (GH), prolactin (PRL) and thyrotropin beta subunit (TSHbeta). Previously, a partial pig PIT1 cDNA and a genomic clone of the entire 3' end of the PIT1 gene was isolated, and polymorphisms at PIT1 were associated with several performance traits in the pig. In order to understand the biological function of the pig PIT1 gene and its possible application in swine genetics, reverse transcriptase-polymerase chain reaction (RT-PCR) was used to complete the cloning of the full length cDNA for pig PIT1. The pig PIT1 cDNA and its deduced protein sequence have approximately 90% and 95% identity, respectively, with the PIT1 cDNA and protein of other mammals (human, bovine, sheep and rodents). Surprisingly, sequence comparison to other pig PIT1 sequences indicated only approximately 93% identity. Additional sequencing confirmed our sequence, and identified a new polymorphism in exon 4. Phylogenetic analysis of several mammalian PIT1 sequences indicates sequencing errors may account for the discrepancies observed in the other pig sequences reported. Several PIT1 alternative spliced forms were also identified by RT-PCR. They were the delta3PIT1 (missing entire exon 3), delta4PIT1 (missing entire exon 4) and PIT1beta (additional 26 amino acids inserted in front of exon 2) transcripts. The delta4PIT1 and PIT1beta transcripts have been found to encode functionally different proteins in rodents. The delta3PIT1 transcript is a novel isoform of PIT1. Potentially different functions between pig delta3PIT1 and PIT1 were analyzed by expressing these proteins in bacteria. The E. coli-expressed PIT1 and delta3PIT1 proteins were used with rat growth hormone (rGH) and rat prolactin (rPRL) promoter DNA in DNA mobility shift assays. The results showed that pig PIT1 can specifically bind rGH and rPRL promoter regions, but that the pig delta3PIT1 cannot, even at very high protein concentrations. Possible protein-protein interactions between

  1. Optic Nerve Pit

    MedlinePlus

    ... What is the effect of optic pit on vision? The pit itself does not affect vision and most patients remain without any symptoms for decades. About 50% of patients start feeling vision deterioration in their 20’s or 30’s. It is ...

  2. Algal and Bacterial Activities in Acidic (pH 3) Strip Mine Lakes

    PubMed Central

    Gyure, Ruth A.; Konopka, Allan; Brooks, Austin; Doemel, William

    1987-01-01

    Reservoir 29 and Lake B are extremely acid lakes (epilimnion pHs of 2.7 and 3.2, respectively), because they receive acidic discharges from coal refuse piles. They differ in that the pH of profundal sediments in Reservoir 29 increased from 2.7 to 3.8 during the period of thermal stratification, whereas permanently anoxic sediments in Lake B had a pH of 6.2. The pH rise in Reservoir 29 sediments was correlated with a temporal increase in H2S concentration in the anaerobic hypolimnion from 0 to >1 mM. The chlorophyll a levels in the epilimnion of Reservoir 29 were low, and the rate of primary production was typical of an oligotrophic system. However, there was a dense 10-cm layer of algal biomass at the bottom of the metalimnion. Production by this layer was low owing to light limitation and possibly H2S toxicity. The specific photosynthetic rates of epilimnetic algae were low, which suggests that nutrient availability is more important than pH in limiting production. The highest photosynthetic rates were obtained in water samples incubated at pH 2.7 to 4. Heterotrophic bacterial activity (measured by [14C]glucose metabolism) was greatest at the sediment/water interface. Bacterial production (assayed by thymidine incorporation) was as high in Reservoir 29 as in a nonacid mesotrophic Indiana lake. PMID:16347430

  3. Algal and bacterial activities in acidic (pH 3) strip mine lakes

    SciTech Connect

    Gyure, R.A.; Konopka, A.; Brooks, A.; Doemel, W.

    1987-09-01

    Reservoir 29 and Lake B are extremely acid lakes (epilimnion pHs of 2.7 and 3.2, respectively), because they receive acidic discharges from coal refuse piles. They differ in that the pH of profundal sediments in Reservoir 29 increased from 2.7 to 3.8 during the period of thermal stratification, whereas permanently anoxic sediments in Lake B had a pH of 6.2. The pH rise in Reservoir 29 sediments was correlated with a temporal increase in H/sub 2/S concentration in the anaerobic hypolimnion from 0 to >1 mM. The chlorophyll a levels in the epilimnion of Reservoir 29 were low, and the rate of primary production was typical of an oligotrophic system. However, there was a dense 10-cm layer of algal biomass at the bottom of the metalimnion. Production by this layer was low owing to light limitation and possibly H/sub 2/S toxicity. The specific photosynthetic rates of epilimnetic algae were low, which suggests that nutrient availability is more important than pH in limiting production. The highest photosynthetic rates were obtained in water samples incubated at pH 2.7 to 4. Heterotrophic bacterial activity (measured by (/sup 14/C)glucose metabolism) was greatest at the sediment/water interface. Bacterial production (assayed by thymidine incorporation) was as high in Reservoir 29 as in a nonacid mesotrophic Indiana lake.

  4. Survey of duckweed diversity in Lake Chao and total fatty acid, triacylglycerol, profiles of representative strains.

    PubMed

    Tang, J; Li, Y; Ma, J; Cheng, J J

    2015-09-01

    Lemnaceae (duckweeds) are widely distributed aquatic flowering plants. Their high growth rate, starch content and suitability for bioremediation make them potential feedstock for biofuels. However, few natural duckweed resources have been investigated in China, and there is no information about total fatty acid (TFA) and triacylglycerol (TAG) composition of duckweeds from China. Here, the genetic diversity of a natural duckweed population collected from Lake Chao, China, was investigated using multilocus sequence typing (MLST). The 54 strains were categorised into four species in four genera, representing 12 distinct sequence types. Strains representing Lemna aequinoctialis and Spirodela polyrhiza were predominant. Interestingly, a surprisingly high degree of genetic diversification within L. aequinoctialis was observed. The four duckweed species revealed a uniform fatty acid composition, with three fatty acids, palmitic acid, linoleic acid and linolenic acid, accounting for more than 80% of the TFA. The TFA in biomass varied among species, ranging from 1.05% (of dry weight, DW) for L. punctata and S. polyrhiza to 1.62% for Wolffia globosa. The four duckweed species contained similar TAG contents, 0.02% mg · DW(-1). The fatty acid profiles of TAG were different from those of TFA, and also varied among the four species. The survey investigated the genetic diversity of duckweeds from Lake Chao, and provides an initial insight into TFA and TAG of four duckweed species, indicating that intraspecific and interspecific variations exist in the content and composition of both TFA and TAG in comparison with other studies.

  5. Australian Acid Playa Lake as a Mars Analog: Results from Sediment Lipid Analysis

    NASA Astrophysics Data System (ADS)

    Graham, H.; Baldridge, A. M.; Stern, J. C.

    2015-12-01

    The ephemeral saline acidic lakes on the Yilgarn Craton of Western Australia have been suggested as geochemical analogues to martian terrains. Both are characterized by interbedded phyllosilicates and hydrated sulfates. On Mars, these areas indicate shifting environmental conditions, from the neutral/alkaline and wet conditions that dominated during the Noachian era to the more familiar dry, acidic conditions that began in the Hesperian. The habitability of such a dynamic environment can be informed by investigation of the Yilgarn Lake system. Previous work has found phospholipid fatty acids (PLFA) evidence of microbial communities in sections of sediment cores taken from Lake Gilmore. These communities include both Gram-positive and -negative bacteria, Actinomycetes, and even methanotrophs. Given recurring detection of methane on the martian surface, evidence of a methane cycling community in an analogous environment is of particular interest. In this study we analyze the carbon isotope composition of bulk organic material as well as extracted lipids from the Lake Gilmore sediment cores at both a near-shore and mid-lake location. These analyses reveal very low accumulations of organic carbon, concentrated primarily in the gypsum-rich near-shore core. The near-shore sediments show a down-core decrease in abundance of organic carbon as well as depletion in the carbon isotope composition (δ13C) with depth. Bulk carbon did not exhibit the unique, highly depleted, diagnostic signature associated with methanotrophic biomass. Compound-specific isotope analysis (CSIA) of carbon in extracted methanotroph PFLAs can confirm the presence of a methane cycling metabolism at depth. Also, additional extractions have isolated lipids associated with lake-edge grasses. These analyses consider both the chain-length distribution and carbon CSIA of these lipids in order to understand the effect of terrestrial detritus on any preserved methanotroph carbon signal, given the very low

  6. Assessing the effectiveness of federal acid rain policy using remote and high elevation lakes in northern New England

    NASA Astrophysics Data System (ADS)

    Baumann, Adam J.

    The 1990 U.S. Clean Air Act Amendments (CAAA) set target reductions for both sulfur and nitrogen emissions to reduce acidic deposition and improve the biologically-relevant chemistry of low ANC surface waters in the United States. The Maine High Elevation Lake Monitoring (HELM) project was designed to complement other acid rain status and trend assessments in the northeast that were known to have underestimated the number of acidic lakes. HELM lakes are more susceptible to the effects of acid deposition than lowland lakes typically included in other surveys because they receive higher amounts of precipitation, and the watersheds are less able to neutralize acidic inputs because of steep slopes, shallow soils, and resistant bedrock. Furthermore, development impacts that affect water quality and cloud our interpretation of recovery from deposition in many lowland lakes are absent in the HELM lakes. Since 1986, HELM surface water SO4-2 concentration has decreased at a rate of 1.6mueq/L/yr.. HELM lake ANC has increased at a rate of 0.58 mueq/L/yr. and hydrogen ion has decreased at a rate of 0.05 mueq/L/yr. since 1986, highlighting the positive effect the CAAA is having on HELM acidity. Over the same time period, HELM DOC has increased at rate of 0.03 mg/L/yr., raising the median DOC in HELM lakes by 21%. Furthermore, we calculate that organic anions (OA-) now contribute 10% to 15% more to total anionic charge while at the same time, the lakes have become 23% more dilute. The increase in DOC has led to a shift in the source of acidity from anthropogenic inorganic (acid rain), to natural organic DOC sources. While this shift appears to complicate the interpretation of acid-base data coming from acid-sensitive lakes, in reality it highlights recovery to a more natural state for these surface waters. A comparison of HELM recovery data to recent data from the New Hampshire Remote Pond (NHRP) project serves to put the NHRP in regional perspective as well as enabling us to

  7. Anthropogenically driven changes in chloride complicate interpretation of base cation trends in lakes recovering from acidic deposition.

    PubMed

    Rosfjord, Catherine H; Webster, Katherine E; Kahl, Jeffrey S; Norton, Stephen A; Fernandez, Ivan J; Herlihy, Alan T

    2007-11-15

    Declines in Ca and Mg in low ANC lakes recovering from acidic deposition are widespread across the northern hemisphere. We report overall increases between 1984 and 2004 in the concentrations of Ca + Mg and Cl in lakes representing the statistical population of nearly 4000 low ANC lakes in the northeast U.S. Increases in Cl occurred in nearly all lakes in urbanized southern New England, but only 18% of lakes in more remote Maine had Cl increases. This spatial pattern implicates road salt application as the major source of the increased Cl salts. Among the 48% of the lake population classified as salt-affected, the median changes in Cl (+133 microeq/L) and Ca + Mg (+47 microeq/ L) were large and positive in direction over the 20 years. However, in the unaffected lakes, Cl remained stable and Ca + Mg decreased (-3 microeq/L), consistent with reported long-term trends in base cations of acid-sensitive lakes. This discrepancy between the Cl groups suggests that changes in ion exchange processes in salt-affected watersheds have altered the geochemical cycling of Ca and Mg. One policy-relevant implication is that waters influenced by Cl salts complicate regional assessments of surface water recovery from "acid rain" related to the passage of the Clean Air Act.

  8. 54. Photocopied August 1978. INTERIOR OF A TAIL PIT OR ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    54. Photocopied August 1978. INTERIOR OF A TAIL PIT OR TAIL RACE AT THE EAST END OF THE POWER HOUSE, SEPTEMBER 17, 1900. THE PRE-MOULDED BLOCKS WHICH FORMED THE SIDE WALLS AND THE ARCHED FOREBAY WALL ARE CLEARLY VISIBLE. THE MONOLITHIC FLOOR OF THE TAIL PIT, HOWEVER, HAS NOT YET BEEN POURED: NEITHER HAS THE MONOLITHIC ARCHED ROOF. (75) - Michigan Lake Superior Power Company, Portage Street, Sault Ste. Marie, Chippewa County, MI

  9. Long-term recovery of lakes in the Adirondack region of New York to decreases in acidic deposition

    NASA Astrophysics Data System (ADS)

    Waller, Kristin; Driscoll, Charles; Lynch, Jason; Newcomb, Dani; Roy, Karen

    2012-01-01

    After years of adverse impacts to the acid-sensitive ecosystems of the eastern United States, the Acid Rain Program and Nitrogen Budget Program were developed to control sulfur dioxide (SO 2) and nitrogen oxide (NO x) emissions through market-based cap and trade systems. We used data from the National Atmospheric Deposition Program's National Trends Network (NTN) and the U.S. EPA Temporally Integrated Monitoring of Ecosystems (TIME) program to evaluate the response of lake-watersheds in the Adirondack region of New York to changes in emissions of sulfur dioxide and nitrogen oxides resulting from the Acid Rain Program and the Nitrogen Budget Program. TIME is a long-term monitoring program designed to sample statistically selected subpopulations of lakes and streams across the eastern U.S. to quantify regional trends in surface water chemistry due to changes in atmospheric deposition. Decreases in wet sulfate deposition for the TIME lake-watersheds from 1991 to 2007 (-1.04 meq m -2-yr) generally corresponded with decreases in estimated lake sulfate flux (-1.46 ± 0.72 meq m -2-yr), suggesting declines in lake sulfate were largely driven by decreases in atmospheric deposition. Decreases in lake sulfate and to a lesser extent nitrate have generally coincided with increases in acid neutralizing capacity (ANC) resulting in shifts in lakes among ANC sensitivity classes. The percentage of acidic Adirondack lakes (ANC <0 μeq L -1) decreased from 15.5% (284 lakes) to 8.3% (152 lakes) since the implementation of the Acid Rain Program and the Nitrogen Budget Program. Two measures of ANC were considered in our analysis: ANC determined directly by Gran plot analysis (ANC G) and ANC calculated by major ion chemistry (ANC calc = CB - CA). While these two metrics should theoretically show similar responses, ANC calc (+2.03 μeq L -1-yr) increased at more than twice the rate as ANC G (+0.76 μeq L -1-yr). This discrepancy has important implications for assessments of lake recovery

  10. Trends in summer chemistry linked to productivity in lakes recovering from acid deposition in the Adirondack region of New York

    USGS Publications Warehouse

    Momen, B.; Lawrence, G.B.; Nierzwicki-Bauer, S. A.; Sutherland, J.W.; Eichler, L.W.; Harrison, J.P.; Boylen, C.W.

    2006-01-01

    The US Environmental Protection Agency established the Adirondack Effects Assessment Program (AEAP) to evaluate and monitor the status of biological communities in lakes in the Adirondack region of New York that have been adversely affected by acid deposition. This program includes chemical analysis of 30 lakes, sampled two to three times each summer. Results of trends analysis for lake chemistry and chlorophyll a (chlor a) are presented for 1994 to 2003, and a general comparison is made with recent results of the Adirondack Long-Term Monitoring (ALTM) Program, which included chemical analysis of all but two of these lakes (plus an additional 24 lakes) monthly, year-round for 1992-2004. Increases in pH were found in 25 of the 30 AEAP lakes (P < 0.05) and increases in acid-neutralizing capacity (ANC) were found in 12 of the 30 lakes (P < 0.05). Concentrations of both SO 42- and Mg 2+ decreased in 11 lakes (P < 0.05), whereas concentrations of NO 3- decreased in 20 lakes (P < 0.05). Concentrations of NH 4+ decreased in 10 lakes at a significance level of P < 0.05 and in three other lakes based on P < 0.1. Concentrations of inorganic and organic monomeric aluminum generally were below the reporting limit of 1.5 ??mol L-1, but decreases were detected in four and five lakes, respectively (P < 0.1). Concentrations of chlor a increased in seven lakes at a significance level of P < 0.05 and two lakes at a significance level of P < 0.1. A significant inverse correlation was also found between chlor a and NO 3- concentrations in nine lakes at a significance level of P < 0.05 and two lakes at a significance level of P < 0.1. Results of AEAP analysis of lake chemistry were similar to those of the ALTM Program, although decreases in SO 42- concentrations were more evident in the year-round ALTM record. Overall, the results suggest (a) a degree of chemical recovery from acidification during the summer, (b) an increase in phytoplankton productivity, and (c) a decreasing trend in

  11. Responses of 20 lake-watersheds in the Adirondack region of New York to historical and potential future acidic deposition.

    PubMed

    Zhou, Qingtao; Driscoll, Charles T; Sullivan, Timothy J

    2015-04-01

    Critical loads (CLs) and dynamic critical loads (DCLs) are important tools to guide the protection of ecosystems from air pollution. In order to quantify decreases in acidic deposition necessary to protect sensitive aquatic species, we calculated CLs and DCLs of sulfate (SO4(2-))+nitrate (NO3-) for 20 lake-watersheds from the Adirondack region of New York using the dynamic model, PnET-BGC. We evaluated lake water chemistry and fish and total zooplankton species richness in response to historical acidic deposition and under future deposition scenarios. The model performed well in simulating measured chemistry of Adirondack lakes. Current deposition of SO4(2-)+NO3-, calcium (Ca2+) weathering rate and lake acid neutralizing capacity (ANC) in 1850 were related to the extent of historical acidification (1850-2008). Changes in lake Al3+ concentrations since the onset of acidic deposition were also related to Ca2+ weathering rate and ANC in 1850. Lake ANC and fish and total zooplankton species richness were projected to increase under hypothetical decreases in future deposition. However, model projections suggest that lake ecosystems will not achieve complete chemical and biological recovery in the future.

  12. 41. THE BEAR PIT (OLD SIDE DINING ROOM). THE ETCHINGS ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    41. THE BEAR PIT (OLD SIDE DINING ROOM). THE ETCHINGS ON THE CEILING BEAMS AND COLUMNS OF PARK WILDLIFE ARE ORIGINAL TO THE OLD SIDE DINING ROOM. THE SIDE DINING ROOM WAS DESIGNED AND BUILT BY ROBERT REAMER IN 1927. IN 1962 WHEN IT WAS CONVERTED INTO THE BEAR PIT A WALL WAS ADDED BETWEEN THE THREE COLUMNS THAT SEPARATE THIS ROOM FROM THE MAIN DINING ROOM. THE ORIGINAL BEAR PIT ETCHINGS DEPICTING BEARS TENDING BAR AND PLAYING THE PIANO WERE MOUNTED ON THE WALL BETWEEN THE COLUMNS. - Old Faithful Inn, 900' northeast of Snowlodge & 1050' west of Old Faithful Lodge, Lake, Teton County, WY

  13. Assessing the recovery of lakes in southeastern Canada from the effects of acidic deposition.

    PubMed

    Jeffries, Dean S; Clair, Thomas A; Couture, Suzanne; Dillon, Peter J; Dupont, Jacques; Keller, Wendel; McNicol, Donald K; Turner, Michael A; Vet, Robert; Weeber, Russell

    2003-04-01

    Reductions in North American sulfur dioxide (SO2) emissions promoted expectations that aquatic ecosystems in southeastern Canada would soon recover from acidification. Only lakes located near smelters that have dramatically reduced emissions approach this expectation. Lakes in the Atlantic provinces, Quebec and Ontario affected only by long-range sources show a general decline in sulfate (SO4(2-)) concentrations, but with a relatively smaller compensating increase in pH or alkalinity. Several factors may contribute to the constrained (or most likely delayed) acidity response: declining base cation concentrations, drought-induced mobilization of SO4(2-), damaged internal alkalinity generation mechanisms, and perhaps increasing nitrate or organic anion levels. Monitoring to detect biological recovery in southeastern Canada is extremely limited, but where it occurs, there is little evidence of recovery outside of the Sudbury/Killarney area. Both the occurrence of Atlantic salmon in Nova Scotia rivers and the breeding success of Common Loons in Ontario lakes are in fact declining although factors beyond acidification also play a role. Chemical and biological models predict that much greater SO2 emission reductions than those presently required by legislation will be needed to promote widespread chemical and latterly, biological recovery. It may be unrealistic to expect that pre-industrial chemical and biological conditions can ever be reestablished in many lakes of southeastern Canada.

  14. Assessing the recovery of lakes in southeastern Canada from the effects of acidic deposition.

    PubMed

    Jeffries, Dean S; Clair, Thomas A; Couture, Suzanne; Dillon, Peter J; Dupont, Jacques; Keller, Wendel; McNicol, Donald K; Turner, Michael A; Vet, Robert; Weeber, Russell

    2003-04-01

    Reductions in North American sulfur dioxide (SO2) emissions promoted expectations that aquatic ecosystems in southeastern Canada would soon recover from acidification. Only lakes located near smelters that have dramatically reduced emissions approach this expectation. Lakes in the Atlantic provinces, Quebec and Ontario affected only by long-range sources show a general decline in sulfate (SO4(2-)) concentrations, but with a relatively smaller compensating increase in pH or alkalinity. Several factors may contribute to the constrained (or most likely delayed) acidity response: declining base cation concentrations, drought-induced mobilization of SO4(2-), damaged internal alkalinity generation mechanisms, and perhaps increasing nitrate or organic anion levels. Monitoring to detect biological recovery in southeastern Canada is extremely limited, but where it occurs, there is little evidence of recovery outside of the Sudbury/Killarney area. Both the occurrence of Atlantic salmon in Nova Scotia rivers and the breeding success of Common Loons in Ontario lakes are in fact declining although factors beyond acidification also play a role. Chemical and biological models predict that much greater SO2 emission reductions than those presently required by legislation will be needed to promote widespread chemical and latterly, biological recovery. It may be unrealistic to expect that pre-industrial chemical and biological conditions can ever be reestablished in many lakes of southeastern Canada. PMID:12839192

  15. Perfluoroalkyl acids in the egg yolk of birds from Lake Shihwa, Korea.

    PubMed

    Yoo, Hoon; Kannan, Kurunthachalam; Kim, Seong Kyu; Lee, Kyu Tae; Newsted, John L; Giesy, John P

    2008-08-01

    Concentrations of perfluoroalkyl acids (PFAs) were measured in egg yolks of three species of birds, the little egret (Egretta garzetta), little ringed plover (Charadrius dubius), and parrot bill (Paradoxornis webbiana), collected in and around Lake Shihwa, Korea, which receives wastewaters from an adjacent industrial complex. Mean concentrations of perfluorooctanesulfonate (PFOS) ranged from 185 to 314 ng/g ww and were similar to those reported for bird eggs from other urban areas. Long-chain perfluorocarboxylic acids (PFCAs) were also found in egg yolks often at great concentrations. Mean concentrations of perfluoroundecanoic acid (PFUnA) ranged from 95 to 201 ng/g ww. Perfluorooctanoic acid was detected in 32 of 44 egg samples, but concentrations were 100-fold less than those of PFOS. Relative concentrations of PFAs in all three species were similar with the predominance of PFOS (45-50%). There was a statistically significant correlation between PFUnA and perfluorodecanoic acid in egg yolks (p < 0.05), suggesting a common source of PFCAs. Using measured egg concentrations and diet concentrations, the ecological risk of the PFOS and PFA mixture to birds in Lake Shihwa was evaluated using two different approaches. Estimated hazard quotients were similar between the two approaches. The concentration of PFOS associated with 90th centile in bird eggs was 100-fold less than the lowest observable adverse effect level determined for birds, and those concentrations were 4-fold less than the suggested toxicity reference values. On the basis of limited toxicological data, current concentrations of PFOS are less than what would be expected to have an adverse effect on birds in the Lake Shihwa region.

  16. Common Loon (Gavia immer) eggshell thickness and egg volume vary with acidity of nest lake in northern Wisconsin

    USGS Publications Warehouse

    Pollentier, C.D.; Kenow, K.P.; Meyer, M.W.

    2007-01-01

    Environmental acidification has been associated with factors that may negatively affect reproduction in many waterbirds. Declines in lake pH can lead to reductions in food availability and quality, or result in the altered availability of toxic metals, such as mercury. A recent laboratory study conducted by the U.S. Geological Survey and the Wisconsin Department of Natural Resources indicated that Common Loon (Gavia immer) chicks hatched from eggs collected on acidic lakes in northern Wisconsin may be less responsive to stimuli and exhibit reduced growth compared to chicks from neutral-pH lakes. Here we report on the relation between Common Loon egg characteristics (eggshell thickness and egg volume) and lake pH, as well as eggshell methylmercury content. Eggs (N = 84) and lake pH measurements were obtained from a four county region of northern Wisconsin. Egg-shells were 3-4% thinner on lakes with pH ??? 6.3 than on neutral-pH lakes and this relation was linear across the pH range investigated (P 0.05, n.s.) or lake pH. Results suggest that low lake pH may be associated with thinner eggshells and reduced egg volume in Common Loons. We speculate on the mechanisms that may lead to this phenomeno.

  17. 7th international conference on acid rock drainage

    SciTech Connect

    Barnhisel, R.I.

    2006-07-01

    This meeting also serves as the 23rd annual meeting of the American Society of Mining and Reclamation. The papers discussed various aspects of acid mine drainage including its impact, sustainability issues, case studies, lessons learned, characterization, closure/land use issues, emerging technologies, forestry/ecology, abandoned mine lands, modelling, pit lakes/backfill, soils and overburden, and treatment.

  18. Buffer capacities of fresh water lakes sensitive to acid rain deposition

    SciTech Connect

    Faust, S.D.; McIntosh, A.

    1983-01-01

    The Van Slyke definition of buffer capacity, the increment of a strong base or strong acid that causes an incremental change in the pH value of water, is better than total alkalinity for defining a water's resistance to acid rain. This Van Slyke value, designated by beta, shows a peak at pH 6.3 for the bicarbonate-carbonate pair, indicating that the effect of acid rain on the pH and alkalinity of natural waters is not deleterious until this peak is traversed. A beta value of zero indicates a dead water with no capacity to neutralize acid. The beta values, pH and total alkalinity of lakes, reservoirs, and streams in New Jersey are given. Data clearly show that pH and alkalinity alone cannot determine buffer capacity. For example: Fairview Lake (pH of 5.5 and alkalinity of 10.2 mg per liter) has a beta value 11 times that of Clyde Potts Reservoir (pH of 7.3, alkalinity of 8.1 mg per liter). 3 references, 1 figure, 1 table.

  19. Sulci Collapse Pits

    NASA Technical Reports Server (NTRS)

    2004-01-01

    [figure removed for brevity, see original site]

    We will be looking at collapse pits for the next two weeks. Collapse pits on Mars are formed in serveral ways. In volcanic areas, channelized lava flows can form roofs which insulate the flowing lava. These features are termed lava tubes on Earth and are common features in basaltic flows. After the lava has drained, parts of the roof of the tube will collapse under its own weight. These collapse pits will only be as deep as the bottom of the original lava tube. Another type of collapse feature associated with volcanic areas arises when very large eruptions completely evacuate the magma chamber beneath the volcano. The weight of the volcano will cause the entire ediface to subside into the void space below it. Structural features including fractures and graben will form during the subsidence. Many times collapse pits will form within the graben. In addition to volcanic collapse pits, Mars has many collapse pits formed when volatiles (such as subsurface ice) are released from the surface layers. As the volatiles leave, the weight of the surrounding rock causes collapse pits to form.

    These collapse pits are found in an area of 'sulci' ridges east of Olympus Mons. Graben cut the ridges, and one graben hosts the collapse pits. It is likely that these collapse pits are related to volatile release from material that filled the lows at some point after graben formation.

    Image information: VIS instrument. Latitude 18.6, Longitude 234.6 East (125.4 West). 19 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in

  20. Development of a total maximum daily load (TMDL) for acid-impaired lakes in the Adirondack region of New York

    NASA Astrophysics Data System (ADS)

    Fakhraei, Habibollah; Driscoll, Charles T.; Selvendiran, Pranesh; DePinto, Joseph V.; Bloomfield, Jay; Quinn, Scott; Rowell, H. Chandler

    2014-10-01

    Acidic deposition has impaired acid-sensitive surface waters in the Adirondack region of New York by decreasing pH and acid neutralizing capacity (ANC). In spite of air quality programs over past decades, 128 lakes in the Adirondacks were classified as “impaired” under Section 303(d) of the Clean Water Act in 2010 due to elevated acidity. The biogeochemical model, PnET-BGC, was used to relate decreases in atmospheric sulfur (S) and nitrogen (N) deposition to changes in lake water chemistry. The model was calibrated and confirmed using observed soil and lake water chemistry data and then was applied to calculate the maximum atmospheric deposition that the impaired lakes can receive while still achieving ANC targets. Two targets of ANC were used to characterize the recovery of acid-impaired lakes: 11 and 20 μeq L-1. Of the 128 acid-impaired lakes, 97 currently have ANC values below the target value of 20 μeq L-1 and 83 are below 11 μeq L-1. This study indicates that a moderate control scenario (i.e., 60% decrease from the current atmospheric S load) is projected to recover the ANC of lakes at a mean rate of 0.18 and 0.05 μeq L-1 yr-1 during the periods 2022-2050 and 2050-2200, respectively. The total maximum daily load (TMDL) of acidity corresponding to this moderate control scenario was estimated to be 7.9 meq S m-2 yr-1 which includes a 10% margin of safety.

  1. Spatial characterization of acid rain stress in Canadian Shield Lakes. Progress report, 1 August 1986-1 February 1987

    SciTech Connect

    Tanis, F.J.

    1987-01-01

    The acidification of lake waters from airborne pollution is of continental proportions both in North America and Europe. A major concern of the acid rain problem is the cumulative ecosystem damage to lakes and forest. The number of lakes affected in northeastern U.S. and on the Canadian Shield is though to be enormous. How seasonal changes in lake transparency are related to annual acidic load was examined. The relationship between variations in lake acidification and ecophysical units was also examined. The utility of Thematic Mapper based observations to measure seasonal changes in the optical transparency in acid lakes was investigated. The potential for this optical response is related to a number of local ecophysical factors with bedrock geology being, perhaps, the most important. Other factors include sulfate deposition, vegetative cover, and terrain drainage/relief. The area of southern Ontario contains a wide variety of geologies from the most acid rain sensitive granite quartzite types to the least sensitive limestone dolomite sediments. Annual sulfate deposition ranges from 1.0 to 4.0 grams/sq m.

  2. Chemical and isotopic variations in the Wiśniówka Mała mine pit water, Holy Cross Mountains (south-central Poland)

    NASA Astrophysics Data System (ADS)

    Migaszewski, Zdzisław M.; Gałuszka, Agnieszka; Hałas, Stanisław; Dąbek, Józef; Dołęgowska, Sabina; Budzyk, Irena; Starnawska, Ewa; Michalik, Artur

    2009-03-01

    In 2005 and 2006, hydrogeochemical study was carried out in the bipartite Wiśniówka Mała pit lake of the Holy Cross Mountains (south-central Poland). This is the largest acidic water body in Poland. This report presents the element concentrations in the water and sediment, stable sulfur and oxygen isotope ratios in the soluble sulfates, and stable oxygen isotope ratio in the water. The scope of the investigation also encompassed mineralogical examinations (scanning electron microscope, X-ray diffraction) of the sediment. The results of this study show that there is a spatial and temporal variability in concentrations of most elements and sulfur isotope ratios in the examined pit lake. The water of the western pond displayed a lower pH with a mean of 3.73 and higher conductivity (390 μS cm-1) as well as higher concentrations of sulfates (156 mg L-1) and most of the cations and anions. The concentrations of Fe2+ and Fe3+ averaged 0.8 and 0.4 mg·L-1. In contrast, the eastern pond water revealed a higher pH (mean of 4.36), lower conductivity (293 μS cm-1) and lower sulfate (90 mg L-1) and trace metal levels. Similar variations were recorded in the stable sulfur isotope ratios. The δ34SV-CDT(SO4 2-) values in the water of the western pit pond were in the range of -6.7 to -4.6‰ (mean of -5.6‰), whereas that in the eastern pit pond ranged from -2.2 to -0.9‰ (-1.6‰). The alkalinity of the entire lake water was below 0.1 mg·L-1 CaCO3. No distinct difference in the δ18OV-SMOW(SO4 2-) was noted between the western and eastern pit ponds. Compared to the Purple Pond in the Sudetes (Poland) and similar sites throughout the world, the examined pit lake is highlighted by distinctly low concentrations of sulfates, iron and other trace metals. Based on this and other studies performed in the Holy Cross Mountains, a conclusion can be drawn that the SO4 2- in the Wiśniówka Mała pit lake water is a mixture of SO4 2- derived from the following sources: (1) pyrite

  3. Chemical, crystallographic and stable isotopic properties of alunite and jarosite from acid-Hypersaline Australian lakes

    USGS Publications Warehouse

    Alpers, C.N.; Rye, R.O.; Nordstrom, D.K.; White, L.D.; King, B.-S.

    1992-01-01

    Chemical, crystallographic and isotopic analyses were made on samples containing alunite and jarosite from the sediments of four acid, hypersaline lakes in southeastern and southwestern Australia. The alunite and jarosite are K-rich with relatively low Na contents based on chemical analysis and determination of unit cell dimensions by powder X-ray diffraction. Correcting the chemical analyses of fine-grained mineral concentrates from Lake Tyrrell, Victoria, for the presence of halite, silica and poorly crystalline aluminosilicates, the following formulas indicate best estimates for solid-solution compositions: for alunite, K0.87Na0.04(H3O)0.09(Al 0.92Fe0.08)3(SO4)2(OH) 6 and for jarosite, K0.89Na0.07(H3O)0.04(Fe 0.80Al0.20)3(SO4)2(OH) 6. The ??D-values of alunite are notably larger than those for jarosite from Lake Tyrrell and it appears that the minerals have closely approached hydrogen isotope equilibrium with the acidic regional groundwaters. The ??D results are consistent with a fractionation ???60-70??? between alunite and jarosite observed in other areas. However, interpretation of ??D results is complicated by large variability in fluid ??DH2O from evaporation, mixing and possible ion hydration effects in the brine. ??D-values of water derived from jarosite by step-wise heating tend to be smaller at 250??C, at which temperature hydronium and other non-hydroxyl water is liberated, than at 550??C, where water is derived from the hydroxyl site, but the differences are not sufficiently different to invalidate measurements of total ??D obtained by conventional, single-step heating methods. ??34S-values for alunite and jarosite from the four lakes (+19.7 to +21.2??? CDT) and for aqueous sulfate from Lake Tyrrell (+18.3 to +19.8???) are close to the values for modern evaporites (+21.5 ??0.3???) and seawater (+20??0.5???) and are probably typical of seawater-derived aerosols in arid coastal environments. ??34-S-values slightly smaller than that for seawater may

  4. Ascraeus Mons Collapse Pits

    NASA Technical Reports Server (NTRS)

    2004-01-01

    [figure removed for brevity, see original site]

    We will be looking at collapse pits for the next two weeks. Collapse pits on Mars are formed in several ways. In volcanic areas, channelized lava flows can form roofs which insulate the flowing lava. These features are termed lava tubes on Earth and are common features in basaltic flows. After the lava has drained, parts of the roof of the tube will collapse under its own weight. These collapse pits will only be as deep as the bottom of the original lava tube. Another type of collapse feature associated with volcanic areas arises when very large eruptions completely evacuate the magma chamber beneath the volcano. The weight of the volcano will cause the entire edifice to subside into the void space below it. Structural features including fractures and graben will form during the subsidence. Many times collapse pits will form within the graben. In addition to volcanic collapse pits, Mars has many collapse pits formed when volatiles (such as subsurface ice) are released from the surface layers. As the volatiles leave, the weight of the surrounding rock causes collapse pits to form.

    These collapse pits are found on the flank of Ascraeus Mons. The pits and channels are all related to lava tube formation and emptying.

    Image information: IR instrument. Latitude 8, Longitude 253.9 East (106.1 West). 100 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science

  5. Lava Tube Collapse Pits

    NASA Technical Reports Server (NTRS)

    2004-01-01

    [figure removed for brevity, see original site]

    We will be looking at collapse pits for the next two weeks. Collapse pits on Mars are formed in several ways. In volcanic areas, channelized lava flows can form roofs which insulate the flowing lava. These features are termed lava tubes on Earth and are common features in basaltic flows. After the lava has drained, parts of the roof of the tube will collapse under its own weight. These collapse pits will only be as deep as the bottom of the original lava tube. Another type of collapse feature associated with volcanic areas arises when very large eruptions completely evacuate the magma chamber beneath the volcano. The weight of the volcano will cause the entire edifice to subside into the void space below it. Structural features including fractures and graben will form during the subsidence. Many times collapse pits will form within the graben. In addition to volcanic collapse pits, Mars has many collapse pits formed when volatiles (such as subsurface ice) are released from the surface layers. As the volatiles leave, the weight of the surrounding rock causes collapse pits to form.

    These collapse pits are found in the southern hemisphere of Mars. They are likely lava tube collapse pits related to flows from Hadriaca Patera.

    Image information: VIS instrument. Latitude -36.8, Longitude 89.6 East (270.4 West). 19 meter/pixel resolution. Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space

  6. Organic matter preservation in the sediment of an acidic mining lake.

    PubMed

    Laskov, Christine; Amelung, Wulf; Peiffer, Stefan

    2002-10-15

    Sustainable management of acidic mining lakes requires knowledge on the origin and reactivity of its sedimentary organic matter. We identified different pools of organic matter (OM) in the Fe-rich sediment (up to 35 wt %) of an acidic (pH 2.8) mining lake using delta13C-signals, C/N ratios, and the markers alkanes, lignin-derived phenols, and benzenepolycarboxylic acids (BPCA). Additionally, a density fractionation was applied to each sediment layer. Three fractions, aquatic (AOM), terrestrial (TOM), and lignite-derived (LOM) organic matter, were discriminated, of which AOM comprises only a small fraction, with a minimum at the sediment bottom. The terrestrial contribution to sedimentary OM is higher than that of AOM but still low throughout the sediment core, whereas lignite-derived OM constitutes the major C-fraction, even in the upper sediment layers. The size of the carbon pools was quantified with a mass-balance approach, in which the BPCA content was utilized as an estimate for the lignite fraction in combination with the delta13C-signals of the three C fractions. The largest amount of OM was found in the heaviest (>2.4 g cm3) of the three density fractions of the two upper sediment layers, which implies strong interaction with iron hydroxides. Comparisons with C-oxidation rates revealed that besides the refractory origin of the OM, sorptive preservation by solid iron phases controls C-reactivity in the sediment and, hence, the internal neutralization capacity of the lake system.

  7. Bioremediation of Pit Lakes - Gilt Edge Mine

    EPA Science Inventory

    The U.S. Environmental Protection Agency (EPA) Region 8 Superfund Office and the EPA National Risk Management Research Laboratory (NRMRL) Mine Waste Technology Program (MWTP) conducted a field-scale treatability study demonstrating an in situ bio/geochemical treatment technology ...

  8. Alba Patera Collapse Pits

    NASA Technical Reports Server (NTRS)

    2004-01-01

    [figure removed for brevity, see original site]

    We will be looking at collapse pits for the next two weeks. Collapse pits on Mars are formed in several ways. In volcanic areas, channelized lava flows can form roofs which insulate the flowing lava. These features are termed lava tubes on Earth and are common features in basaltic flows. After the lava has drained, parts of the roof of the tube will collapse under its own weight. These collapse pits will only be as deep as the bottom of the original lava tube. Another type of collapse feature associated with volcanic areas arises when very large eruptions completely evacuate the magma chamber beneath the volcano. The weight of the volcano will cause the entire edifice to subside into the void space below it. Structural features including fractures and graben will form during the subsidence. Many times collapse pits will form within the graben. In addition to volcanic collapse pits, Mars has many collapse pits formed when volatiles (such as subsurface ice) are released from the surface layers. As the volatiles leave, the weight of the surrounding rock causes collapse pits to form.

    This image of the Alba Patera region has both lava tube collapse pits (running generally east/west) and subsidence related collapse within structural grabens.

    Image information: IR instrument. Latitude 26.9, Longitude 256.5 East (103.5 West). 100 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA

  9. Sulci Collapse Pits

    NASA Technical Reports Server (NTRS)

    2004-01-01

    [figure removed for brevity, see original site]

    We will be looking at collapse pits for the next two weeks. Collapse pits on Mars are formed in several ways. In volcanic areas, channelized lava flows can form roofs which insulate the flowing lava. These features are termed lava tubes on Earth and are common features in basaltic flows. After the lava has drained, parts of the roof of the tube will collapse under its own weight. These collapse pits will only be as deep as the bottom of the original lava tube. Another type of collapse feature associated with volcanic areas arises when very large eruptions completely evacuate the magma chamber beneath the volcano. The weight of the volcano will cause the entire edifice to subside into the void space below it. Structural features including fractures and graben will form during the subsidence. Many times collapse pits will form within the graben. In addition to volcanic collapse pits, Mars has many collapse pits formed when volatiles (such as subsurface ice) are released from the surface layers. As the volatiles leave, the weight of the surrounding rock causes collapse pits to form.

    This is the Noctis Labyrinthus region of Mars. These collapse pits are forming along structural fractures that are allowing the release of volatiles from the subsurface. This is believed to be the way that chaos terrain forms on Mars. This area represents the early stage of chaos formation.

    Image information: VIS instrument. Latitude -12.6, Longitude 264 East (96 West). 19 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in

  10. Tharsis Collapse Pits

    NASA Technical Reports Server (NTRS)

    2004-01-01

    [figure removed for brevity, see original site]

    We will be looking at collapse pits for the next two weeks. Collapse pits on Mars are formed in several ways. In volcanic areas, channelized lava flows can form roofs which insulate the flowing lava. These features are termed lava tubes on Earth and are common features in basaltic flows. After the lava has drained, parts of the roof of the tube will collapse under its own weight. These collapse pits will only be as deep as the bottom of the original lava tube. Another type of collapse feature associated with volcanic areas arises when very large eruptions completely evacuate the magma chamber beneath the volcano. The weight of the volcano will cause the entire edifice to subside into the void space below it. Structural features including fractures and graben will form during the subsidence. Many times collapse pits will form within the graben. In addition to volcanic collapse pits, Mars has many collapse pits formed when volatiles (such as subsurface ice) are released from the surface layers. As the volatiles leave, the weight of the surrounding rock causes collapse pits to form.

    These collapse pits are found within the extensive lava flows of the Tharsis region. They are related to lava tubes, likely coming from Ascraeus Mons.

    Image information: VIS instrument. Latitude 22.8, Longitude 266.8 East (93.2 West). 19 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office

  11. Alba Patera Collapse Pits

    NASA Technical Reports Server (NTRS)

    2004-01-01

    [figure removed for brevity, see original site]

    We will be looking at collapse pits for the next two weeks. Collapse pits on Mars are formed in several ways. In volcanic areas, channelized lava flows can form roofs which insulate the flowing lava. These features are termed lava tubes on Earth and are common features in basaltic flows. After the lava has drained, parts of the roof of the tube will collapse under its own weight. These collapse pits will only be as deep as the bottom of the original lava tube. Another type of collapse feature associated with volcanic areas arises when very large eruptions completely evacuate the magma chamber beneath the volcano. The weight of the volcano will cause the entire edifice to subside into the void space below it. Structural features including fractures and graben will form during the subsidence. Many times collapse pits will form within the graben. In addition to volcanic collapse pits, Mars has many collapse pits formed when volatiles (such as subsurface ice) are released from the surface layers. As the volatiles leave, the weight of the surrounding rock causes collapse pits to form.

    These collapse pits are found within graben surrounding Alba Patera. Alba Patera is an old volcano that has subsided after it's magma chamber was evacuated.

    Image information: VIS instrument. Latitude 43.1, Longitude 259.4 East (100.6 West). 19 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA

  12. Tractus Catena Collapse Pits

    NASA Technical Reports Server (NTRS)

    2004-01-01

    [figure removed for brevity, see original site]

    We will be looking at collapse pits for the next two weeks. Collapse pits on Mars are formed in several ways. In volcanic areas, channelized lava flows can form roofs which insulate the flowing lava. These features are termed lava tubes on Earth and are common features in basaltic flows. After the lava has drained, parts of the roof of the tube will collapse under its own weight. These collapse pits will only be as deep as the bottom of the original lava tube. Another type of collapse feature associated with volcanic areas arises when very large eruptions completely evacuate the magma chamber beneath the volcano. The weight of the volcano will cause the entire edifice to subside into the void space below it. Structural features including fractures and graben will form during the subsidence. Many times collapse pits will form within the graben. In addition to volcanic collapse pits, Mars has many collapse pits formed when volatiles (such as subsurface ice) are released from the surface layers. As the volatiles leave, the weight of the surrounding rock causes collapse pits to form.

    These collapse pits are found in graben located in Tractus Catena. These features are related to subsidence after magma chamber evacuation of Alba Patera.

    Image information: VIS instrument. Latitude 35.8, Longitude 241.7 East (118.3 West). 19 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA

  13. Pre-industrial atmospheric pollution: was it important for the pH of acid-sensitive Swedish lakes?

    PubMed

    Bindler, Richard; Korsman, Tom; Renberg, Ingemar; Högberg, Peter

    2002-09-01

    Acid rain has caused extensive surface water acidification in Sweden since the mid-20th century. Sulfur emissions from fossil-fuel burning and metal production were the main sources of acid deposition. In the public consciousness, acid deposition is strongly associated with the industrial period, in particular the last 50 years. However, studies of lake-water pH development and atmospheric pollution, based on analyses of lake sediment deposits, have shown the importance of a long-term perspective. Here, we present a conceptual argument, using the sediment record, that large-scale atmospheric acid deposition has impacted the environment since at least Medieval times. Sulfur sources were the pre-industrial mining and metal industries that produced silver, lead and other metals from sulfide ores. This early excess sulfur deposition in southern Sweden did not cause surface water acidification; on the contrary, it contributed to alkalization, i.e. increased pH and productivity of the lakes. Suggested mechanisms are that the excess sulfur caused enhanced cation exchange in catchment soils, and that it altered iron-phosphorus cycling in the lakes, which released phosphorus and increased lake productivity.

  14. 12. Detail of engine pit in machine shop section of ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    12. Detail of engine pit in machine shop section of roundhouse. Engine house section of roundhouse visible in background through rectangular openings. View to southeast. - Duluth & Iron Range Rail Road Company Shops, Roundhouse, Southwest of downtown Two Harbors, northwest of Agate Bay, Two Harbors, Lake County, MN

  15. 106. Photocopied August 1978. EXTENSION OF TAIL PIT WALLS, APRIL ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    106. Photocopied August 1978. EXTENSION OF TAIL PIT WALLS, APRIL 28, 1917. THE TIMBERWORK IN THE FOREGROUND WAS USED AS A COMBINATION COFFER DAM AND FORM FOR POURING THE CONCRETE TAIL RACE WALL EXTENSION. IN THE BACKGROUND ALONG THE POWER HOUSE SEVERAL COMPLETED WALL EXTENSIONS CAN BE SEEN DIMLY. (787) - Michigan Lake Superior Power Company, Portage Street, Sault Ste. Marie, Chippewa County, MI

  16. Gas flushing through hyper-acidic crater lakes: the next steps within a reframed monitoring time window

    NASA Astrophysics Data System (ADS)

    Rouwet, Dmitri

    2016-04-01

    Tracking variations in the chemical composition, water temperature and pH of brines from peak-activity crater lakes is the most obvious way to forecast phreatic activity. Volcano monitoring intrinsically implies a time window of observation that should be synchronised with the kinetics of magmatic processes, such as degassing and magma intrusion. To decipher "how much time ago" a variation in degassing regime actually occurred before eventually being detected in a crater lake is key, and depends on the lake water residence time. The above reasoning assumes that gas is preserved as anions in the lake water (SO4, Cl, F anions), in other words, that scrubbing of acid gases is complete and irreversible. Less is true. Recent work has confirmed, by direct MultiGas measurement from evaporative plumes, that even the strongest acid in liquid medium (i.e. SO2) degasses from hyper-acidic crater lakes. The less strong acid HCl has long been recognised as being more volatile than hydrophyle in extremely acidic solutions (pH near 0), through a long-term steady increase in SO4/Cl ratios in the vigorously evaporating crater lake of Poás volcano. We now know that acidic gases flush through hyper-acidic crater lake brines, but we don't know to which extend (completely or partially?), and with which speed. The chemical composition hence only reflects a transient phase of the gas flushing through the lake. In terms of volcanic surveillance this brings the advantage that the monitoring time window is definitely shorter than defined by the water chemistry, but yet, we do not know how much shorter. Empirical experiments by Capaccioni et al. (in press) have tried to tackle this kinetic problem for HCl degassing from a "lab-lake" on the short-term (2 days). With this state of the art in mind, two new monitoring strategies can be proposed to seek for precursory signals of phreatic eruptions from crater lakes: (1) Tracking variations in gas compositions, fluxes and ratios between species in

  17. Pitting of 3003 aluminum

    SciTech Connect

    Lee, R.

    1996-12-31

    The Advanced Photon Source is a state-of-the-art synchrotron light source. The storage ring vacuum chamber is fabricated from 6061 extruded Al. Water connections to the vacuum chambers that were fabricated from 3003 Al had developed water leaks, which were subsequently remedied after considerable investigations. Materials subjected to the pitting analysis in this study are 3003, 6061, and 6063 Al.

  18. PIT Coating Requirements Analysis

    SciTech Connect

    MINTEER, D.J.

    2000-10-20

    This study identifies the applicable requirements for procurement and installation of a coating intended for tank farm valve and pump pit interior surfaces. These requirements are intended to be incorporated into project specification documents and design media. This study also evaluates previously recommended coatings and identifies requirement-compliant coating products.

  19. Detecting Cavitation Pitting Without Disassembly

    NASA Technical Reports Server (NTRS)

    Barkhoudarian, S.

    1986-01-01

    Technique for detecting cavitation pitting in pumps, turbines, and other machinery uses low-level nuclear irradiation. Isotopes concentrated below surface emit gamma radiation, a portion of which is attenuated by overlying material. Where there are cavitation pits, output of gamma-ray detector fluctuates as detector is scanned near pits. Important to detect cavitation pits because nozzle, turbine blade, or other pump component weakened by cavitation could fail catastrophically and cause machine to explode.

  20. High Elevation Lakes of the Western US: Are we Studying Systems Recovering from Excess Atmospheric Deposition of Acids and Nutrients?

    NASA Astrophysics Data System (ADS)

    Sickman, J. O.

    2011-12-01

    Instrumental records and monitoring of high elevation lakes began in most areas of the western US in the early 1980s. Much effort has been devoted to detecting changes in these aquatic ecosystems resulting from increased atmospheric deposition of acids and nutrients. However, there is growing evidence that thresholds for atmospheric pollutants were crossed much earlier in the 20th Century and that some of the subsequent hydrochemical and ecological changes observed in these lakes may be the result of recovery from earlier atmospheric forcing. We examine responses of high elevation lakes to atmospheric deposition on annual to century timescales using data from a 29-year study of Emerald Lake (Sequoia National Park) and paleolimnological analyses of other high elevation lakes incorporating diatom species analyses and geochemical proxies for fossil-fuel burning. At Emerald Lake, we have observed multiple transitions between nitrogen and phosphorus limitation of phytoplankton, the earliest of which occurred in the beginning of the 1980s and may be the result of reduction in N deposition due to the Clean Air Act. Critical loads analyses incorporating diatom species in lake sediments suggest that thresholds for N deposition were crossed in the period of 1950-1980 in the Rocky Mountains and likely much earlier, 1900-1920, in the Sierra Nevada. Diatom species composition is strongly controlled by acid neutralizing capacity (ANC) in the Sierra Nevada and we have observed a pronounced decline and recovery of ANC over the period of 1920-1980 in some Sierra Nevada lakes that coincides with the abundance of spheroidal carbonaceous particles (i.e., a diagnostic tracer of fossil fuel combustion) preserved in lake sediments; these patterns appear to be driven by increased emissions of oxidized N and S in the mid-20th Century and reductions in acid precursor levels caused by the Clean Air Act in the 1970s. Thus, when interpreting observational records from western high elevation

  1. Enrichment of Non-Terrestrial L-Proteinogenic Amino Acids by Aqueous Alteration on the Tagish Lake Meteorite Parent Body

    NASA Technical Reports Server (NTRS)

    Glavin, Daniel P.; Elsila, Jamie E.; Burton, Aaron S.; Callahan, Michael P.; Dworkin, Jason P.; Herd, Christopher D. K.

    2012-01-01

    The distribution and isotopic and enantiomeric compositions of amino acids found in three distinct fragments of the Tagish Lake C2-type carbonaceous chondrite were investigated via liquid chromatography fluorescence detection time-of-flight mass spectrometry and gas chromatography isotope ratio mass spectrometry. Large L-enantiomeric excesses (L(sub ee) approx. 43 to 59%) of the a-hydrogen aspartic and glutamic amino acids were measured in Tagish Lake, whereas alanine, another alpha-hydrogen protein amino acid, was found to be nearly racemic (D approx. L) using both techniques. Carbon isotope measurements of D- and L-aspartic acid and D- and L-alanine in Tagish Lake fall well outside of the terrestrial range and indicate that the measured aspartic acid enantioenrichment is indigenous to the meteorite. Alternate explanations for the Lexcesses of aspartic acid such as interference from other compounds present in the sample, analytical biases, or terrestrial amino acid contamination were investigated and rejected. These results can be explained by differences in the solid-solution phase behavior of aspartic acid, which can form conglomerate enantiopure solids during crystallization, and alanine, which can only form racemic crystals.

  2. Effects of Acid on Plant Litter Decomposition in an Arctic Lake

    PubMed Central

    McKinley, Vicky L.; Vestal, J. Robie

    1982-01-01

    The effects of acid on the microbial decomposition of the dominant aquatic macrophyte (Carex sp.) in Toolik Lake, Alaska were studied in microcosms during the ice-free season of 1980. Toolik Lake is slightly buffered, deep, and very oligotrophic. Microbial activities, as determined by 14C-acetate incorporation into extractable lipids, associated with Carex litter were significantly (P < 0.01) reduced within 2 days at pHs of 3.0 and 4.0, but not 5.0, 5.5, or 6.0, as compared with ambient controls (pH 7.4). ATP levels were significantly reduced at pH 3.0, but not at the other pHs tested. After 18 days, microbial activity significantly correlated with weight loss (P < 0.05), nitrogen content (P < 0.01), and C/N ratios (P < 0.01) of the litter, but did not correlate with ATP levels. Scanning electron microscopy of the litter surface revealed that the fungi present at ambient pH did not become dominant at pHs below 5.5, diatoms were absent below pH 4.0, and bacterial numbers and extracellular slime were greatly reduced at pH 4.0 and below. Mineralization of Carex14C-lignin-labeled or 14C-cellulose-labeled lignocellulose was reduced at pH 2.0, but not at pH 4.0, 5.0, or 6.0, compared with controls (pH 7). We concluded that if the pH of the water from this slightly buffered lake was sufficiently reduced, rates of litter decomposition would be significantly reduced. Images PMID:16346015

  3. Effects of acid on plant litter decomposition in an arctic lake. [Carex aquatilis

    SciTech Connect

    McKinley, V.L.; Vestal, J.R.

    1982-05-01

    The effects of acid on the microbial decomposition of the dominant aquatic macrophyte (Carex sp.) in Toolik Lake, Alaska were studied in microcosms during the ice-free season of 1980. Toolik Lake is slightly buffered, deep, and very oligotrophic. Microbial activities, as determined by /sup 14/C-acetate incorporation into extractable lipids, associated with Carex litter were signficantly (P < 0.01) reduced within 2 days at pHs of 3.0 and 4.0, but not 5.0, 5.5 or 6.0, as compared with ambient controls (pH 7.4). ATP levels were signficantly reduced at pH 3.0 but not at the other pHs tested. After 18 days, microbial activity signficantly correlated with weight loss (P < 0.05), nitrogen content (P < 0.01), and C/N ratios (P < 0.01) of the liter, but did not correlate with ATP levels. Scanning electron microscopy of the litter surface revealed that the fungi present at ambient pH did not become domimant at pHs below 5.5, diatoms were absent below pH 4.0, and bacterial numbers and extracellular slime were greatly reduced at pH 4.0 and below. Mineralization of Carex /sup 14/C-lignin-labeled or /sup 14/C-cellulose-labeled ligno-cellulose was reduced at pH 2.0, but not at pH 4.0, 5.0, or 6.0, compared with controls (pH '). We concluded that if the pH of the water from this slightly buffered lake was sufficiently reduced, rates of litter decomposition would be significantly reduced.

  4. The 2005 catastrophic acid crater lake drainage, lahar, and acidic aerosol formation at Mount Chiginagak volcano, Alaska, USA: Field observations and preliminary water and vegetation chemistry results

    USGS Publications Warehouse

    Schaefer, J.R.; Scott, W.E.; Evans, William C.; Jorgenson, J.; McGimsey, R.G.; Wang, B.

    2008-01-01

    A mass of snow and ice 400-m-wide and 105-m-thick began melting in the summit crater of Mount Chiginagak volcano sometime between November 2004 and early May 2005, presumably owing to increased heat flux from the hydrothermal system, or possibly from magma intrusion and degassing. In early May 2005, an estimated 3.8??106 m3 of sulfurous, clay-rich debris and acidic water, with an accompanying acidic aerosol component, exited the crater through a tunnel at the base of a glacier that breaches the south crater rim. Over 27 km downstream, the acidic waters of the flood inundated an important salmon spawning drainage, acidifying Mother Goose Lake from surface to depth (approximately 0.5 km3 in volume at a pH of 2.9 to 3.1), killing all aquatic life, and preventing the annual salmon run. Over 2 months later, crater lake water sampled 8 km downstream of the outlet after considerable dilution from glacial meltwater was a weak sulfuric acid solution (pH = 3.2, SO4 = 504 mg/L, Cl = 53.6 mg/L, and F = 7.92 mg/L). The acid flood waters caused severe vegetation damage, including plant death and leaf kill along the flood path. The crater lake drainage was accompanied by an ambioructic flow of acidic aerosols that followed the flood path, contributing to defoliation and necrotic leaf damage to vegetation in a 29 km2 area along and above affected streams, in areas to heights of over 150 m above stream level. Moss species killed in the event contained high levels of sulfur, indicating extremely elevated atmospheric sulfurcontent. The most abundant airborne phytotoxic constituent was likely sulfuric acid aerosols that were generated during the catastrophic partial crater lake drainage event. Two mechanisms of acidic aerosol formation are proposed: (1) generation of aerosol mist through turbulent flow of acidic water and (2) catastrophic gas exsolution. This previously undocumented phenomenon of simultaneous vegetationdamaging acidic aerosols accompanying drainage of an acidic crater

  5. The 2005 catastrophic acid crater lake drainage, lahar, and acidic aerosol formation at Mount Chiginagak volcano, Alaska, USA: Field observations and preliminary water and vegetation chemistry results

    NASA Astrophysics Data System (ADS)

    Schaefer, Janet R.; Scott, William E.; Evans, William C.; Jorgenson, Janet; McGimsey, Robert G.; Wang, Bronwen

    2008-07-01

    A mass of snow and ice 400-m-wide and 105-m-thick began melting in the summit crater of Mount Chiginagak volcano sometime between November 2004 and early May 2005, presumably owing to increased heat flux from the hydrothermal system, or possibly from magma intrusion and degassing. In early May 2005, an estimated 3.8 × 106 m3 of sulfurous, clay-rich debris and acidic water, with an accompanying acidic aerosol component, exited the crater through a tunnel at the base of a glacier that breaches the south crater rim. Over 27 km downstream, the acidic waters of the flood inundated an important salmon spawning drainage, acidifying Mother Goose Lake from surface to depth (approximately 0.5 km3 in volume at a pH of 2.9 to 3.1), killing all aquatic life, and preventing the annual salmon run. Over 2 months later, crater lake water sampled 8 km downstream of the outlet after considerable dilution from glacial meltwater was a weak sulfuric acid solution (pH = 3.2, SO4 = 504 mg/L, Cl = 53.6 mg/L, and F = 7.92 mg/L). The acid flood waters caused severe vegetation damage, including plant death and leaf kill along the flood path. The crater lake drainage was accompanied by an ambioructic flow of acidic aerosols that followed the flood path, contributing to defoliation and necrotic leaf damage to vegetation in a 29 km2 area along and above affected streams, in areas to heights of over 150 m above stream level. Moss species killed in the event contained high levels of sulfur, indicating extremely elevated atmospheric sulfur content. The most abundant airborne phytotoxic constituent was likely sulfuric acid aerosols that were generated during the catastrophic partial crater lake drainage event. Two mechanisms of acidic aerosol formation are proposed: (1) generation of aerosol mist through turbulent flow of acidic water and (2) catastrophic gas exsolution. This previously undocumented phenomenon of simultaneous vegetation-damaging acidic aerosols accompanying drainage of an acidic

  6. Polar Cap Pits

    NASA Technical Reports Server (NTRS)

    2005-01-01

    17 August 2005 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows kidney bean-shaped pits, and other pits, formed by erosion in a landscape of frozen carbon dioxide. This images shows one of about a dozen different patterns that are common in various locations across the martian south polar residual cap, an area that has been receiving intense scrutiny by the MGS MOC this year, because it is visible on every orbit and in daylight for most of 2005.

    Location near: 86.9oS, 6.9oW Image width: width: 3 km (1.9 mi) Illumination from: upper left Season: Southern Spring

  7. Cracked and Pitted Plain

    NASA Technical Reports Server (NTRS)

    2003-01-01

    MGS MOC Release No. MOC2-536, 6 November 2003

    This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a typical view--at 1.5 meters (5 feet) per pixel--of surfaces in far western Utopia Planitia. In this region, the plains have developed cracks and pit chains arranged in a polygonal pattern. The pits form by collapse along the trend of a previously-formed crack. This picture is located near 45.0oN, 275.4oW. This April 2003 image covers an area 3 km (1.9 mi) wide and is illuminated by sunlight from the lower left.

  8. Phytoplankton limitation by phosphorus and zooplankton grazing in an acidic Adirondack lake

    SciTech Connect

    Singer, R.; Evans, G.L.; Pratt, N.C.

    1984-08-01

    Lakes which are believed to have been acidified by atmospheric deposition of anthropogenic substances are known for their unusually high water clarity and low nutrient concentrations. Some evidence indicates that alterations in predator/prey relationships, an indirect effect of acidification, bring about the increase in water clarity. Enclosures were used to study the effects of phosphorus addition and zooplankton removal on the phytoplankton of an acidic lake in the Adirondack Mountains of New York. Fertilized enclosures had significantly lower alkalinities and contained significantly more dissolved oxygen after the incubation period than did unfertilized enclosures. The P concentration remained at or near the limit of detection in the unfertilized enclosures. The phytoplankton population bloomed after the addition of 80 micro g/liter of phosphate as KH/sub 2/PO/sub 4/. The response was measured by cell counts of the dominant phytoplankton. Chlamydomonas, and by changes in chlorophyll a concentration. About half the number of algal cells were present after the two week incubation when zooplankton were not removed, indicating that zooplankton herbivory can influence, but not totally control, the algal production. 46 references.

  9. Ariel's Densely Pitted Surface

    NASA Technical Reports Server (NTRS)

    1986-01-01

    This mosaic of the four highest-resolution images of Ariel represents the most detailed Voyager 2 picture of this satellite of Uranus. The images were taken through the clear filter of Voyager's narrow-angle camera on Jan. 24, 1986, at a distance of about 130,000 kilometers (80,000 miles). Ariel is about 1,200 km (750 mi) in diameter; the resolution here is 2.4 km (1.5 mi). Much of Ariel's surface is densely pitted with craters 5 to 10 km (3 to 6 mi) across. These craters are close to the threshold of detection in this picture. Numerous valleys and fault scarps crisscross the highly pitted terrain. Voyager scientists believe the valleys have formed over down-dropped fault blocks (graben); apparently, extensive faulting has occurred as a result of expansion and stretching of Ariel's crust. The largest fault valleys, near the terminator at right, as well as a smooth region near the center of this image, have been partly filled with deposits that are younger and less heavily cratered than the pitted terrain. Narrow, somewhat sinuous scarps and valleys have been formed, in turn, in these young deposits. It is not yet clear whether these sinuous features have been formed by faulting or by the flow of fluids.

    JPL manages the Voyager project for NASA's Office of Space Science.

  10. Decomposition of Alternative Chirality Amino Acids by Alkaliphilic Anaerobe from Owens Lake, California

    NASA Technical Reports Server (NTRS)

    Townsend, Alisa; Pikuta, Elena V.; Guisler, Melissa; Hoover, Richard B.

    2009-01-01

    The study of alkaliphilic microbial communities from anaerobic sediments of Owens and Mono Lakes in California led to the isolation of a bacterial strain capable of metabolizing amino acids with alternative chirality. According to the phylogenetic analysis, the anaerobic strain BK1 belongs to the genus Tindallia; however, despite the characteristics of other described species of this genus, the strain BK1 was able to grow on D-arginine and Dlysine. Cell morphology of this strain showed straight, motile, non-spore-forming rods with sizes 0.45 x 1.2-3 microns. Physiological characteristics of the strain showed that it is catalase negative, obligately anaerobic, mesophilic, and obligately alkaliphilic. This isolate is unable to grow at pH 7 and requires CO3 (2-) ions for growth. The strain has chemo-heterotrophic metabolism and is able to ferment various proteolysis products and some sugars. It plays the role of a primary anaerobe within the trophic chain of an anaerobic microbial community by the degradation of complex protein molecules to smaller and less energetic molecules. The new isolate requires NaCl for growth, and can grow within the range of 0.5-13 %, with the optimum at 1 % NaCl (w/v). The temperature range for the growth of the new isolate is 12-40 C with optimum at 35 C. The pH range for the growth of strain BK1 occurs between 7.8 and 11.0 with optimum at 9.5. This paper presents detailed physiological characteristics of the novel isolate from Owens Lake, a unique relic ecosystem of Astrobiological significance, and makes an accent on the ability of this strain to utilize L-amino acids.

  11. Influence of in ovo mercury exposure, lake acidity, and other factors on common loon egg and chick quality in Wisconsin.

    PubMed

    Kenow, Kevin P; Meyer, Michael W; Rossmann, Ronald; Gray, Brian R; Arts, Michael T

    2015-08-01

    A field study was conducted in Wisconsin (USA) to characterize in ovo mercury (Hg) exposure in common loons (Gavia immer). Total Hg mass fractions ranged from 0.17 µg/g to 1.23 µg/g wet weight in eggs collected from nests on lakes representing a wide range of pH (5.0-8.1) and were modeled as a function of maternal loon Hg exposure and egg laying order. Blood total Hg mass fractions in a sample of loon chicks ranged from 0.84 µg/g to 3.86 µg/g wet weight at hatch. Factors other than mercury exposure that may have persistent consequences on development of chicks from eggs collected on low-pH lakes (i.e., egg selenium, calcium, and fatty acid mass fractions) do not seem to be contributing to reported differences in loon chick quality as a function of lake pH. However, it was observed that adult male loons holding territories on neutral-pH lakes were larger on average than those occupying territories on low-pH lakes. Differences in adult body size of common loons holding territories on neutral-versus low-pH lakes may have genetic implications for differences in lake-source-related quality (i.e., size) in chicks. The tendency for high in ovo Hg exposure and smaller adult male size to co-occur in low-pH lakes complicates the interpretation of the relative contributions of each to resulting chick quality.

  12. Influence of in ovo mercury exposure, lake acidity, and other factors on common loon egg and chick quality in Wisconsin

    USGS Publications Warehouse

    Kenow, Kevin P.; Meyer, Michael W.; Rossmann, Ronald; Gray, Brian R.; Arts, Michael T.

    2015-01-01

    A field study was conducted in Wisconsin (USA) to characterize in ovo mercury (Hg) exposure in common loons (Gavia immer). Total Hg mass fractions ranged from 0.17 mg/g to 1.23mg/g wet weight in eggs collected from nests on lakes representing a wide range of pH (5.0–8.1) and were modeled as a function of maternal loon Hg exposure and egg laying order. Blood total Hg mass fractions in a sample of loon chicks ranged from 0.84ug/g to 3.86 ug/g wet weight at hatch. Factors other than mercury exposure that may have persistent consequences on development of chicks from eggs collected on low-pH lakes (i.e., egg selenium, calcium, and fatty acid mass fractions) do not seem to be contributing to reported differences in loon chick quality as a function of lake pH. However, it was observed that adult male loons holding territories on neutral-pH lakes were larger on average than those occupying territories on low-pH lakes. Differences in adult body size of common loons holding territories on neutral-versus low-pH lakes may have genetic implications for differences in lake-source-related quality (i.e., size) in chicks. The tendency for high in ovo Hg exposure and smaller adult male size to co-occur in low-pH lakes complicates the interpretation of the relative contributions of each to resulting chick quality.

  13. Open-pit explosives

    SciTech Connect

    Dannenberg, J.

    1982-07-01

    This paper explains how mine operators are taking a closer look at the power of explosives and how primary breakage affects other open-pit mining costs. Slurries have overcome most of the disadvantages attributed to them in their early years and may replace Anfo. Effective blasting is the key to an efficient, low-cost mining operation. Reviews are presented on research in crater studies, computer-aided design, the expanding gas theory, and high-speed motion picture cameras that show the importance of shock energy in fracturing the rock interfaces throughout the burden. The paper concludes with MSHA-approved courses in blasting offered throughout the US.

  14. The effect of normal pulsed Nd-YAG laser irradiation on pits and fissures in human teeth.

    PubMed

    Bahar, A; Tagomori, S

    1994-01-01

    The effects of normal pulsed Nd-YAG laser irradiation on the acid resistance of human dental enamel of pits and fissures, the cleaning of the pit and fissure contents and fluoride uptake into deep pits and fissures were examined. The acid resistance of the pit and fissure enamel was evaluated by the amount of dissolved calcium per square millimeter of the surface area. The pit and fissure enamel treated with laser irradiation obtained an acid resistance 30% higher than that of the unlased controls. The cleaning effect of laser irradiation on the pit and fissure contents was compared with chemicomechanical and mechanical methods. The laser irradiation was found to clean the pits and fissures to a greater depth without alterating the shape of pits and fissures, compared with the other two methods. The distribution of calcium, phosphorus and fluoride in the enamel of the pits and fissures was then measured by electron probe microanalyzer. At the entrance and in the deep part of the pits and fissures, the fluoride content of the enamel treated with acidulated phosphate fluoride after laser irradiation was higher than that of the enamel treated with acidulated phosphate fluoride alone. These results thus suggest that Nd-YAG laser irradiation might be effective in increasing the acid resistance of the pit and fissure enamel, while removing the pit and fissure debris contents and increasing the fluoride uptake into the pit and fissure enamel.

  15. Inter- and intra-annual chemical variability during the ice-free season in lakes with different flushing rates and acid deposition histories.

    PubMed

    Arnott, Shelley E; Dillon, Peter J; Somers, Keith; Keller, Bill

    2003-01-01

    Quantifying chemical variability in different lake types is important for the assessment of both chemical and biological responses to environmental change. For monitoring programs that emphasize a large number of lakes at the expense of frequent samples, high variability may influence how representative single samples are of the average conditions of individual lakes. Intensive temporal data from long-term research sites provide a unique opportunity to assess chemical variability in lakes with different characteristics. We compared the intra- and inter-annual variability of four acidification related variables (Gran alkalinity, pH, sulphate concentration, and total base cation concentration) in four lakes with different flushing rates and acid deposition histories. Variability was highest in lakes with high flushing rates and was not influenced by historic acid deposition in our study lakes. This has implications for the amount of effort required in monitoring programs. Lakes with high flushing rates will require more frequent sampling intervals than lakes with low flushing rates. Consideration of specific lake types should be included in the design of monitoring programs.

  16. Lake Superior, Duluth, MN

    NASA Technical Reports Server (NTRS)

    1973-01-01

    This view shows the west end of Lake Superior and Duluth, MN (47.0N, 91.0W). Portions of Minnesota, Michigan and Ontario, Canada are in the scene. The Duluth metropolitan area is at the west end of the lake. The discoloration plume in the water at Duluth is the result of tailings from the iron ore smelters that process the iron ore from the nearby open pit mines seen near the upper left corner of the photo.

  17. Quantitative High-Pressure Liquid Chromatography-Fluorescence Determination of Some Important Lower Fatty Acids in Lake Sediments

    PubMed Central

    Hordijk, Kees A.; Cappenberg, Thomas E.

    1983-01-01

    For the quantitative determination of traces of fatty acids in pore water, several gas and liquid chromatographic methods were tested and discussed. Direct determination by gas-liquid chromatography with the use of formic acid-saturated carrier gas was found to be the least laborious method, but it is only recommended for the determination of volatile acids such as acetate and higher homologs. For the determination of lactate and formate, a derivatization procedure is necessary. The determination of these acids as phenacyl or benzyl esters was complicated by contaminants in the reagents. For this reason, a high-pressure liquid chromatography procedure with 4-bromomethyl-7-methoxycoumarin as a fluorescent labeling reagent is preferred. With this method, lactic, acetic, and formic acids could be demonstrated simultaneously at the nanogram level in 5-ml samples. Profiles of these acids in the sediment of Lake Vechten were measured, and they showed correlations with sulfate-reducing and methanogenic bacterial activities. PMID:16346362

  18. 13. DETAIL WEST OF TURBINE PIT SHOWING PIT DRAINED AND ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    13. DETAIL WEST OF TURBINE PIT SHOWING PIT DRAINED AND TURBINE EXPOSED. ORIGINAL WATER LEVEL SHOWN BY LINE JUST ABOVE ARCHED OPENING TO LEFT. WATER LINE AFTER 1982 INSTALLATION OF FLASH BOARDS REVEALED BY DARK STAIN. - Middle Creek Hydroelectric Dam, On Middle Creek, West of U.S. Route 15, 3 miles South of Selinsgrove, Selinsgrove, Snyder County, PA

  19. An evaluation of problems arising from acid mine drainage in the vicinity of Shasta Lake, Shasta County, California

    USGS Publications Warehouse

    Fuller, Richard H.; Shay, J.M.; Ferreira, R.F.; Hoffman, R.J.

    1978-01-01

    Streams draining the mined areas of massive sulfide ore deposits in the Shasta Mining Districts of northern California are generally acidic and contain large concentrations of dissolved metals, including iron, copper, and zinc. The streams, including Flat, Little Backbone, Spring, West Squaw, Horse, and Zinc Creeks, discharge into Shasta Reservoir and the Sacramento River and have caused numerous fish kills. The sources of pollution are discharge from underground mines, streams that flow into open pits, and streams that flow through pyritic mine dumps where the oxidation of pyrite and other sulfide minerals results in the production of acid and the mobilization of metals. Suggested methods of treatment include the use of air and hydraulic seals in the mines, lime neutralization of mine effluent, channeling of runoff and mine effluent away from mine and tailing areas, and the grading and sealing of mine dumps. A comprehensive preabatement and postabatement program is recommended to evaluate the effects of any treatment method used. (Woodard-USGS)

  20. Indirect effects of UV radiation: Fe{sup 2+} enrichment stimulates picocyanobacterial growth in Clearwater acidic Shield lakes

    SciTech Connect

    Auclair, J.C.

    1995-12-31

    Ozone depletion and associated increases in UVB radiation could increase the photoreduction of iron in Shield lakes of the Boreal forest zone. Since photoreduced iron (I) is more soluble than iron (III), and the re-oxidation rate slower in acidic (pH = 5--6) lakes, phytoplankton growth and/or species composition may be altered where iron is growth limiting. The differential enrichment of UV{sub A+B} transparent herbivore-free (< 65 mu) lakewater enclosures ({approximately}500L) with phosphorus, phosphorus and Fe (II) and phosphorus, ammonium and Fe (II) revealed that the Spring phytoplankton abundance of an oligotrophic Clearwater acidic Canadian Shield lake was limited by herbivore grazing, rather than by a limiting nutrient. However, in the herbivore-free enriched enclosures the addition of Fe{sup 2+} greatly stimulated picocyanobacterial growth and grazing activity by mixotrophic species comprising the microbial food web of this lake. In spite of a 10-fold increase in the mixotrophic chrysophytes, the authors did not discern any strong competitive interactions among the mixotrophic organisms, strongly suggesting that the latter obtain most if not all of their iron quota from their picoplanktonic prey.

  1. Aluminium speciation in streams and lakes of the UK Acid Waters Monitoring Network, modelled with WHAM.

    PubMed

    Tipping, E; Carter, H T

    2011-03-15

    The Windermere Humic Aqueous Model (WHAM) incorporating Humic Ion-Binding Model VI was applied to analytical data from the United Kingdom Acid Waters Monitoring Network, collected for 22 streams and lakes over the period 1988-2007, to calculate the chemical speciation of monomeric aluminium (Al(mon)) in 3087 water samples. Model outputs were compared with analytical measurements of labile and non-labile Al(mon) concentrations, the former being equated with inorganic forms of Al(mon) and the latter with organically-complexed metal. Raw analytical data were used, and also data produced by applying a correction for the possible dissociation of organically-complexed Al(mon), and therefore its underestimation, during passage through the analytical cation-exchange column. Model calibration was performed by finding the conversion factor, F(FADOC), between the concentration of isolated fulvic acid, with default ion-binding properties, required by the model, and the measured concentration of dissolved organic carbon, [DOC]. For both uncorrected and corrected data, the value of F(FADOC) for streams was greater than for lakes, indicating greater binding activity towards aluminium. Model fits were better using uncorrected analytical data, but the values of F(FADOC) obtained from corrected data agreed more closely with previous estimates. The model provided reasonably good explanations of differences in aluminium speciation between sampling sites, and of temporal variations at individual sites. With total monomeric concentration as input, WHAM calculations might substitute for analytical speciation measurements, or aid analytical quality control. Calculated Al(3+) activities, a(Al3+), showed a pH-dependence similar to that previously found for other surface waters, and the modelling exercise identified differences between waters of up to two orders of magnitude in the value of a(Al3+) at a given pH. The model gives the net charge of dissolved organic matter, which is calculated

  2. Ultimate open pit stochastic optimization

    NASA Astrophysics Data System (ADS)

    Marcotte, Denis; Caron, Josiane

    2013-02-01

    Classical open pit optimization (maximum closure problem) is made on block estimates, without directly considering the block grades uncertainty. We propose an alternative approach of stochastic optimization. The stochastic optimization is taken as the optimal pit computed on the block expected profits, rather than expected grades, computed from a series of conditional simulations. The stochastic optimization generates, by construction, larger ore and waste tonnages than the classical optimization. Contrary to the classical approach, the stochastic optimization is conditionally unbiased for the realized profit given the predicted profit. A series of simulated deposits with different variograms are used to compare the stochastic approach, the classical approach and the simulated approach that maximizes expected profit among simulated designs. Profits obtained with the stochastic optimization are generally larger than the classical or simulated pit. The main factor controlling the relative gain of stochastic optimization compared to classical approach and simulated pit is shown to be the information level as measured by the boreholes spacing/range ratio. The relative gains of the stochastic approach over the classical approach increase with the treatment costs but decrease with mining costs. The relative gains of the stochastic approach over the simulated pit approach increase both with the treatment and mining costs. At early stages of an open pit project, when uncertainty is large, the stochastic optimization approach appears preferable to the classical approach or the simulated pit approach for fair comparison of the values of alternative projects and for the initial design and planning of the open pit.

  3. Flyover Modeling of Planetary Pits

    NASA Astrophysics Data System (ADS)

    Balakumar, A.; Bhasin, N.; Daids, O.; Shanor, R.; Snyder, K.; Whittaker, W.

    2015-10-01

    This research uses vision, inertial, and LIDAR sensors to build a high resolution model of a planetary pit as a landing vehicle flies overhead. Pits allow access to subterranean caves, but cannot be fully observed from orbit due to their geometry.

  4. PIT Tagging Anurans

    USGS Publications Warehouse

    McCreary, Brome

    2008-01-01

    The following video demonstrates a procedure to insert a passive integrated transponder (PIT) tag under the skin of an anuran (frog or toad) for research and monitoring purposes. Typically, a 12.5 mm tag (0.5 in.) is used to uniquely identify individual anurans as smal as 40 mm (1.6 in.) in length from snout to vent. Smaller tags are also available and allow smaller anurans to be tagged. The procedure does not differ for other sizes of tages or other sizes of anurans. Anyone using this procedure should ensure that the tag is small enough to fit easily behind the sacral hump of the anuran, as shown in this video.

  5. Comparative study of cadmium and lead accumulations in Cambarus bartoni (Fab. ) (Decapoda, Crustacea) from an acidic and a neutral lake

    SciTech Connect

    Keenan, S.; Alikhan, M.A. )

    1991-07-01

    The purpose of the study reported in this paper was to compare concentrations of lead and cadmium in the sediment and water, as well as in the crayfish, Cambarus Bartoni (Fab.) (Decapoda - Crustacea) trapped from an acidic and a neutral lake in the Sudbury district of Northeastern Ontario. Hepatopancreatic, alimentary canal, tail muscles and exoskeletal concentrations in the crayfish are also examined to determine specific tissue sites for these accumulations.

  6. 30. VIEW DOWN INTO TURBINE PIT SHOWING WICKET GATE CONTROL ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    30. VIEW DOWN INTO TURBINE PIT SHOWING WICKET GATE CONTROL MECHANISM AND MAIN SHAFT OF I. P. MORRIS TURBINE. TURBINE BUILT BY I. P. MORRIS & DE LA VERGNE, INC. OF PHILADELPHIA, PA, AND INSTALLED IN 1925. TURBINE RATED AT 18,000 HP AT 113.3 RPM UNDER 18.5 FEET OF HEAD. - Lake Lynn Hydroelectric Power House & Dam, Cheat River, Morgantown, Monongalia County, WV

  7. Brooktrout Lake case study: biotic recovery from acid deposition 20 years after the 1990 Clean Air Act Amendments.

    PubMed

    Sutherland, James W; Acker, Frank W; Bloomfield, Jay A; Boylen, Charles W; Charles, Donald F; Daniels, Robert A; Eichler, Lawrence W; Farrell, Jeremy L; Feranec, Robert S; Hare, Matthew P; Kanfoush, Sharon L; Preall, Richard J; Quinn, Scott O; Rowell, H Chandler; Schoch, William F; Shaw, William H; Siegfried, Clifford A; Sullivan, Timothy J; Winkler, David A; Nierzwicki-Bauer, Sandra A

    2015-03-01

    The Adirondack Mountain region is an extensive geographic area (26,305 km(2)) in upstate New York where acid deposition has negatively affected water resources for decades and caused the extirpation of local fish populations. The water quality decline and loss of an established brook trout (Salvelinus fontinalis [Mitchill]) population in Brooktrout Lake were reconstructed from historical information dating back to the late 1880s. Water quality and biotic recovery were documented in Brooktrout Lake in response to reductions of S deposition during the 1980s, 1990s, and 2000s and provided a unique scientific opportunity to re-introduce fish in 2005 and examine their critical role in the recovery of food webs affected by acid deposition. Using C and N isotope analysis of fish collagen and state hatchery feed as well as Bayesian assignment tests of microsatellite genotypes, we document in situ brook trout reproduction, which is the initial phase in the restoration of a preacidification food web structure in Brooktrout Lake. Combined with sulfur dioxide emissions reductions promulgated by the 1990 Clean Air Act Amendments, our results suggest that other acid-affected Adirondack waters could benefit from careful fish re-introduction protocols to initiate the ecosystem reconstruction of important components of food web dimensionality and functionality.

  8. Brooktrout Lake case study: biotic recovery from acid deposition 20 years after the 1990 Clean Air Act Amendments.

    PubMed

    Sutherland, James W; Acker, Frank W; Bloomfield, Jay A; Boylen, Charles W; Charles, Donald F; Daniels, Robert A; Eichler, Lawrence W; Farrell, Jeremy L; Feranec, Robert S; Hare, Matthew P; Kanfoush, Sharon L; Preall, Richard J; Quinn, Scott O; Rowell, H Chandler; Schoch, William F; Shaw, William H; Siegfried, Clifford A; Sullivan, Timothy J; Winkler, David A; Nierzwicki-Bauer, Sandra A

    2015-03-01

    The Adirondack Mountain region is an extensive geographic area (26,305 km(2)) in upstate New York where acid deposition has negatively affected water resources for decades and caused the extirpation of local fish populations. The water quality decline and loss of an established brook trout (Salvelinus fontinalis [Mitchill]) population in Brooktrout Lake were reconstructed from historical information dating back to the late 1880s. Water quality and biotic recovery were documented in Brooktrout Lake in response to reductions of S deposition during the 1980s, 1990s, and 2000s and provided a unique scientific opportunity to re-introduce fish in 2005 and examine their critical role in the recovery of food webs affected by acid deposition. Using C and N isotope analysis of fish collagen and state hatchery feed as well as Bayesian assignment tests of microsatellite genotypes, we document in situ brook trout reproduction, which is the initial phase in the restoration of a preacidification food web structure in Brooktrout Lake. Combined with sulfur dioxide emissions reductions promulgated by the 1990 Clean Air Act Amendments, our results suggest that other acid-affected Adirondack waters could benefit from careful fish re-introduction protocols to initiate the ecosystem reconstruction of important components of food web dimensionality and functionality. PMID:25621941

  9. Novel Halomonas sp. B15 isolated from Larnaca Salt Lake in Cyprus that generates vanillin and vanillic acid from ferulic acid.

    PubMed

    Vyrides, Ioannis; Agathangelou, Maria; Dimitriou, Rodothea; Souroullas, Konstantinos; Salamex, Anastasia; Ioannou, Aristostodimos; Koutinas, Michalis

    2015-08-01

    Vanillin is a high value added product with many applications in the food, fragrance and pharmaceutical industries. A natural and low-cost method to produce vanillin is by microbial bioconversions through ferulic acid. Until now, limited microorganisms have been found capable of bioconverting ferulic acid to vanillin at high yield. This study aimed to screen halotolerant strains of bacteria from Larnaca Salt Lake which generate vanillin and vanillic acid from ferulic acid. From a total of 50 halotolenant/halophilic strains 8 grew in 1 g/L ferulic acid and only 1 Halomonas sp. B15 and 3 Halomonas elognata strains were capable of bioconverting ferulic acid to vanillic acid at 100 g NaCl/L. The highest vanillic acid (365 mg/L) at these conditions generated by Halomonas sp. B15 which corresponds to ferulic acid bioconversion yield of 36.5%. Using the resting cell technique with an initial ferulic acid concentration of 0.5 g/L at low salinity, the highest production of vanillin (245 mg/L) took place after 48 h, corresponding to a bioconversion yield of 49%. This is the first reported Halomonas sp. with high yield of vanillin production from ferulic acid at low salinity.

  10. Acidification in the Adirondacks: defining the biota in trophic levels of 30 chemically diverse acid-impacted lakes.

    PubMed

    Nierzwicki-Bauer, Sandra A; Boylen, Charles W; Eichler, Lawrence W; Harrison, James P; Sutherland, James W; Shaw, William; Daniels, Robert A; Charles, Donald F; Acker, Frank W; Sullivan, Timothy J; Momen, Bahram; Bukaveckas, Paul

    2010-08-01

    The Adirondack Mountains in New York State have a varied surficial geology and chemically diverse surface waters that are among the most impacted by acid deposition in the U.S. No single Adirondack investigation has been comprehensive in defining the effects of acidification on species diversity, from bacteria through fish, essential for understanding the full impact of acidification on biota. Baseline midsummer chemistry and community composition are presented for a group of chemically diverse Adirondack lakes. Species richness of all trophic levels except bacteria is significantly correlated with lake acid-base chemistry. The loss of taxa observed per unit pH was similar: bacterial genera (2.50), bacterial classes (1.43), phytoplankton (3.97), rotifers (3.56), crustaceans (1.75), macrophytes (3.96), and fish (3.72). Specific pH criteria were applied to the communities to define and identify acid-tolerant (pH<5.0), acid-resistant (pH 5.0-5.6), and acid-sensitive (pH>5.6) species which could serve as indicators. Acid-tolerant and acid-sensitive categories are at end-points along the pH scale, significantly different at P<0.05; the acid-resistant category is the range of pH between these end-points, where community changes continually occur as the ecosystem moves in one direction or another. The biota acid tolerance classification (batc) system described herein provides a clear distinction between the taxonomic groups identified in these subcategories and can be used to evaluate the impact of acid deposition on different trophic levels of biological communities.

  11. Atmospheric oxalic acid and related secondary organic aerosols in Qinghai Lake, a continental background site in Tibet Plateau

    NASA Astrophysics Data System (ADS)

    Meng, Jingjing; Wang, Gehui; Li, Jianjun; Cheng, Chunlei; Cao, Junji

    2013-11-01

    Summertime PM2.5 aerosols collected from Qinghai Lake (3200 m a.s.l.), a remote continental site in the northeastern part of Tibetan Plateau, were analyzed for dicarboxylic acids (C2-C11), ketocarboxylic acids and α-dicarbonyals. Oxalic acid (C2) is the dominant dicarboxylic acid in the samples, followed by malonic, succinic and azelaic acids. Total dicarboxylic acids (231 ± 119 ng m-3), ketocarboxylic acids (8.4 ± 4.3 ng m-3), and α-dicarbonyls (2.7 ± 2.1 ng m-3) at the Tibetan background site are 2-5 times less than those detected in lowland areas such as 14 Chinese megacities. Compared to those in other urban and marine areas enhancements in relative abundances of C2/total diacids and diacids-C/WSOC of the PM2.5 samples suggest that organic aerosols in the region are more oxidized due to strong solar radiation. Molecular compositions and air mass trajectories demonstrate that the above secondary organic aerosols in the Qinghai Lake atmosphere are largely derived from long-range transport. Ratios of oxalic acid, glyoxal and methylglyoxal to levoglucosan in PM2.5 aerosols emitted from household burning of yak dung, a major energy source for Tibetan in the region, are 30-400 times lower than those in the ambient air, which further indicates that primary emission from biomass burning is a negligible source of atmospheric oxalic acid and α-dicarbonyls at this background site.

  12. Amino acid-assimilating phototrophic heliobacteria from soda lake environments: Heliorestis acidaminivorans sp. nov. and 'Candidatus Heliomonas lunata'.

    PubMed

    Asao, Marie; Takaichi, Shinichi; Madigan, Michael T

    2012-07-01

    Two novel taxa of heliobacteria, Heliorestis acidaminivorans sp. nov. strain HR10B(T) and 'Candidatus Heliomonas lunata' strain SLH, were cultured from shoreline sediments/soil of Lake El Hamra (Egypt) and lake water/benthic sediments of Soap Lake (USA), respectively; both are highly alkaline soda lakes. Cells of strain HR10B were straight rods, while cells of strain SLH were curved rods. Both organisms were obligate anaerobes, produced bacteriochlorophyll g, and lacked intracytoplasmic photosynthetic membrane systems. Although the absorption spectrum of strain HR10B was typical of other heliobacteria, that of strain SLH showed unusually strong absorbance of the OH-chlorophyll a component. Major carotenoids of both organisms were OH-diaponeurosporene glucosyl esters, as in other alkaliphilic heliobacteria, and both displayed an alkaliphilic and mesophilic phenotype. Strain HR10B was remarkable among heliobacteria in its capacity to photoassimilate a number of carbon sources, including several amino acids. Nitrogenase activity was observed in strain HR10B, but not in strain SLH. The 16S ribosomal RNA gene tree placed strain HR10B within the genus Heliorestis, but distinct from other described species. By contrast, strain SLH was phylogenetically more closely related to neutrophilic heliobacteria and is the first alkaliphilic heliobacterium known outside of the genus Heliorestis.

  13. Sorption of toluene by humic acids derived from lake sediment and mountain soil at different pH.

    PubMed

    Chang Chien, S W; Chen, C Y; Chang, J H; Chen, S H; Wang, M C; Mannepalli, Madhava Rao

    2010-05-15

    Contamination of soil and groundwater with BTEX compounds (benzene, toluene, ethylbenzene, and xylene) depends on the sorption behavior of these compounds by soil organic matter (SOM) and humic acids (HAs). In this study sorption of toluene by HAs extracted from lake sediment and mountain soil was investigated. HA suspensions were adjusted to pH 4.00, 6.00, or 8.00 and made to the concentration of 200 mg L(-1). Each HA suspension or solution was subjected to particle size analysis using high performance particle sizer (HPPS). The particle size of HA from lake sediment was around 1000-1200 nm while that from mountain soil was 220-320 nm at suspension pH 4.00. Kinetic studies showed that sorption of toluene by the two HAs followed pseudo-first-order and mainly pseudo-zero-order kinetics. At suspension pH 4.00, the sorption of toluene by the two HAs was best described by Langmuir and Temkin adsorption isotherm models. Further, sorption of toluene by the lake sediment HA was significantly greater than that by mountain soil HA. It was thus suggested that the lake sediment HA with larger particle size may develop beneficially chemical conformation for sorption of toluene and related compounds in soil and associated environments.

  14. Amino acid-assimilating phototrophic heliobacteria from soda lake environments: Heliorestis acidaminivorans sp. nov. and 'Candidatus Heliomonas lunata'.

    PubMed

    Asao, Marie; Takaichi, Shinichi; Madigan, Michael T

    2012-07-01

    Two novel taxa of heliobacteria, Heliorestis acidaminivorans sp. nov. strain HR10B(T) and 'Candidatus Heliomonas lunata' strain SLH, were cultured from shoreline sediments/soil of Lake El Hamra (Egypt) and lake water/benthic sediments of Soap Lake (USA), respectively; both are highly alkaline soda lakes. Cells of strain HR10B were straight rods, while cells of strain SLH were curved rods. Both organisms were obligate anaerobes, produced bacteriochlorophyll g, and lacked intracytoplasmic photosynthetic membrane systems. Although the absorption spectrum of strain HR10B was typical of other heliobacteria, that of strain SLH showed unusually strong absorbance of the OH-chlorophyll a component. Major carotenoids of both organisms were OH-diaponeurosporene glucosyl esters, as in other alkaliphilic heliobacteria, and both displayed an alkaliphilic and mesophilic phenotype. Strain HR10B was remarkable among heliobacteria in its capacity to photoassimilate a number of carbon sources, including several amino acids. Nitrogenase activity was observed in strain HR10B, but not in strain SLH. The 16S ribosomal RNA gene tree placed strain HR10B within the genus Heliorestis, but distinct from other described species. By contrast, strain SLH was phylogenetically more closely related to neutrophilic heliobacteria and is the first alkaliphilic heliobacterium known outside of the genus Heliorestis. PMID:22588563

  15. Sources and haloacetic acid/trihalomethane formation potentials of aquatic humic substances in the Wakarusa River and Clinton Lake near Lawrence, Kansas

    USGS Publications Warehouse

    Pomes, M.L.; Larive, C.K.; Thurman, E.M.; Green, W.R.; Orem, W.H.; Rostad, C.E.; Coplen, T.B.; Cutak, B.J.; Dixon, A.M.

    2000-01-01

    Gram quantities of aquatic humic substances (AHS) were extracted from the Wakarusa River-Clinton Lake Reservoir system, near Lawrence, KS, to support nuclear magnetic resonance (NMR) experimental studies, report concentrations of dissolved organic carbon (DOC) and AHS, define sources of the AHS, and determine if the AHS yield sufficient quantities of haloacetic acids (HAA5) and trihalomethanes (THM4) that exceed U.S. Environmental Protection Agency (EPA) Maximum Contaminant Levels (MCL) in drinking water. AHS from the Wakarusa River and Clinton Lake originated from riparian forest vegetation, reflected respective effects of soil organic matter and aquatic algal/bacterial sources, and bore evidence of biological degradation and photodegradation. AHS from the Wakarusa River showed the effect of terrestrial sources, whereas Clinton Lake humicacid also reflected aquatic algal/bacterial sources. Greater amounts of carbon attributable to tannin-derived chemical structures may correspond with higher HAA5 and THM4 yields for Clinton Lake fulvic acid. Prior to appreciable leaf-fall from deciduous trees, the combined (humic and fulvic acid) THM4 formation potentials for the Wakarusa River approached the proposed EPA THM4 Stage I MCL of 80 ??g/L, and the combined THM4 formation potential for Clinton Lake slightly exceeded the proposed THM4 Stage II MCL of 40 ??g/L. Finally, AHS from Clinton Lake could account for most (>70%) of the THM4 concentrations in finished water from the Clinton Lake Water Treatment Plant based on September 23, 1996, THM4 results.Gram quantities of aquatic humic substances (AHS) were extracted from the Wakarusa River-Clinton Lake Reservoir system, near Lawrence, KS, to support nuclear magnetic resonance (NMR) experimental studies, report concentrations of dissolved organic carbon (DOC) and AHS, define sources of the AHS, and determine if the AHS yield sufficient quantities of haloacetic acids (HAA5) and trihalomethanes (THM4) that exceed U

  16. Isotope biogeochemical assessment of natural biodegradation processes in open cast pit mining landscapes

    NASA Astrophysics Data System (ADS)

    Jeschke, Christina; Knöller, Kay; Koschorreck, Matthias; Ussath, Maria; Hoth, Nils

    2014-05-01

    In Germany, a major share of the energy production is based on the burning of lignite from open cast pit mines. The remediation and re-cultivation of the former mining areas in the Lusatian and Central German lignite mining district is an enormous technical and economical challenge. After mine closures, the surrounding landscapes are threatened by acid mine drainage (AMD), i.e. the acidification and mineralization of rising groundwater with metals and inorganic contaminants. The high content of sulfur (sulfuric acid, sulfate), nitrogen (ammonium) and iron compounds (iron-hydroxides) deteriorates the groundwater quality and decelerates sustainable development of tourism in (former) mining landscapes. Natural biodegradation or attenuation (NA) processes of inorganic contaminants are considered to be a technically low impact and an economically beneficial solution. The investigations of the stable isotope compositions of compounds involved in NA processes helps clarify the dynamics of natural degradation and provides specific informations on retention processes of sulfate and nitrogen-compounds in mine dump water, mine dump sediment, and residual pit lakes. In an active mine dump we investigated zones where the process of bacterial sulfate reduction, as one very important NA process, takes place and how NA can be enhanced by injecting reactive substrates. Stable isotopes signatures of sulfur and nitrogen components were examined and evaluated in concert with hydrogeochemical data. In addition, we delineated the sources of ammonium pollution in mine dump sediments and investigated nitrification by 15N-labeling techniques to calculate the limit of the conversion of harmful ammonium to nitrate in residual mining lakes. Ultimately, we provided an isotope biogeochemical assessment of natural attenuation of sulfate and ammonium at mine dump sites and mining lakes. Also, we estimated the risk potential for water in different compartments of the hydrological system. In

  17. Degassing of Aso Volcano, Japan through an Acid Crater Lake: Differentiation of Volcanic Gas-Hydrothermal Fluids Deduced from Volcanic Plume Chemistry

    NASA Astrophysics Data System (ADS)

    Shinohara, H.; Yoshikawa, S.; Miyabuchi, Y.

    2010-12-01

    Yudamari crater lake at Nakadake, Aso volcano, Japan is a hot and acid crater lake of 200-m-diameter. The active degassing occurs from a fumarolic area and through the crater lake, with SO2 emission of about 500 t/d. The fumarolic area locates at the southern wall of the crater lake shore and its activity is characterized by the high-temperature gas emission indicated by the red-glowing fumaroles. Degassing and evaporation are also intense from the crater lake surface. Since the crater lake is surrounded by steep slope, we cannot reach neither to the crater lake nor the fumarolic area for direct sampling. In order to characterize the degassing activity of these sources and evaluate differentiation process at volcanic-hydrothermal system beneath the crater lake, we conducted measurements of volcanic plumes to estimate composition of gases originating from the two gas sources; the crater lake (lake gas) and the high-temperature fumaroles (fumarolic gas) by the use of the Multi-GAS and alkaline-filter technique. Compositions of the lake gas and fumarolic gas are variable depending of the observation period, but the gases from the two sources have distinct compositions; fumarolic gases have higher CO2/SO2, HCl/SO2 and lower SO2/H2S ratio than the lake gases, but they have similar H2/CO2 ratios. The low HCl and H2S contents of the lake gases indicate the lake gases are derived by evaporation of the lake water, and their HCl/H2O ratios are consistent with this model. However, the high H2 and CO2 content in the lake gases also indicate that the lake gas is a mixture of bubbling gases and evaporation. The H2/CO2 ratio, which is less likely to be changed by dissolution into the lake water, is similar for the fumarolic gas and the lake gas, suggesting that both gases are derived from a common high-temperature fluid. The RH (=log(H2/H2O)) and SO2/H2S ratio of the fumarolic gases range from -2 to -3 and from10 to 30, respectively, corresponding to the apparent equilibrium

  18. Patterns of epipelic algal distribution in an acidic adirondack lake. [Hapalosiphon pumilus; Fragilaria acidobiontica; Navicula tenuicephala; Navicula subtilissima

    SciTech Connect

    Roberts, D.A.; Boylen, C.W.

    1988-06-01

    The biovolume and species composition of epipelic algae along sediment depth gradients were sampled seasonally in an acidic oligotrophic lake in the Adirondack Park in New York State. The epipelic algal community of Woods Lake (Herkimer Co., NY) was dominated by diatoms and cyanobacteria. Distinct depth zonation patterns of community composition were evident. Total algal biovolume increased with depth due to a dense cyanobacterial mat on the sediments in deeper water (5-8 m). This mat was dominated by a single species of cyanobacteria, Hapalosiphon pumilus (Kuetz). Kirchner, which accounted for the later summer maximum in total biovolume at 7 m. The shallower (1-4 m) epipelic communities were dominated by diatoms, which showed a spring maximum in total biovolume and were dominated by Fragilaria acidobiontica Charles, Navicula tenuicephala Hust, and N. subtilissima Cl.

  19. Quantification of 15 bile acids in lake charr feces by ultra-high performance liquid chromatography–tandem mass spectrometry

    USGS Publications Warehouse

    Li, Ke; Buchinger, Tyler J.; Bussy, Ugo; Fissette, Skye D; Johnson, Nicholas; Li, Weiming

    2015-01-01

    Many fishes are hypothesized to use bile acids (BAs) as chemical cues, yet quantification of BAs in biological samples and the required methods remain limited. Here, we present an UHPLC–MS/MS method for simultaneous, sensitive, and rapid quantification of 15 BAs, including free, taurine, and glycine conjugated BAs, and application of the method to fecal samples from lake charr (Salvelinus namaycush). The analytes were separated on a C18 column with acetonitrile–water (containing 7.5 mM ammonium acetate and 0.1% formic acid) as mobile phase at a flow rate of 0.25 mL/min for 12 min. BAs were monitored with a negative electrospray triple quadrupole mass spectrometer (Xevo TQ-S™). Calibration curves of 15 BAs were linear over the concentration range of 1.00–5,000 ng/mL. Validation revealed that the method was specific, accurate, and precise. The method was applied to quantitative analysis of feces extract of fry lake charr and the food they were eating. The concentrations of analytes CA, TCDCA, TCA, and CDCA were 242.3, 81.2, 60.7, and 36.2 ng/mg, respectively. However, other taurine conjugated BAs, TUDCA, TDCA, and THDCA, were not detected in feces of lake charr. Interestingly, TCA and TCDCA were detected at high concentrations in food pellets, at 71.9 and 38.2 ng/mg, respectively. Application of the method to feces samples from lake charr supported a role of BAs as chemical cues, and will enhance further investigation of BAs as chemical cues in other fish species.

  20. Comet 67P's Pitted Surface

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2015-11-01

    High-resolution imagery of comet 67P ChuryumovGerasimenko has revealed that its surface is covered in active pits some measuring hundreds of meters both wide and deep! But what processes caused these pits to form?Pitted LandscapeESAs Rosetta mission arrived at comet 67P in August 2014. As the comet continued its journey around the Sun, Rosetta extensively documented 67Ps surface through high-resolution images taken with the on-board instrument NavCam. These images have revealed that active, circular depressions are a common feature on the comets surface.In an attempt to determine how these pits formed, an international team of scientists led by Olivier Mousis (Laboratory of Astrophysics of Marseille) has run a series of simulations of a region of the comet the Seth region that contains a 200-meter-deep pit. These simulations include the effects of various phase transitions, heat transfer through the matrix of ices and dust, and gas diffusion throughout the porous material.Escaping VolatilesAdditional examples of pitted areas on 67Ps northern-hemisphere surface include the Ash region and the Maat region (both imaged September 2014 by NavCam) [Mousis et al. 2015]Previous studies have already eliminated two potential formation mechanisms for the pits: impacts (the sizes of the pits werent right) and erosion due to sunlight (the pits dont have the right shape). Mousis and collaborators assume that the pits are instead caused by the depletion of volatile materials chemical compounds with low boiling points either via explosive outbursts at the comets surface, or via sinkholes opening from below the surface. But what process causes the volatiles to deplete when the comet heats?The authors simulations demonstrate that volatiles trapped beneath the comets surface either in icy structures called clathrates or within amorphous ice can be suddenly released as the comet warms up. The team shows that the release of volatiles from these two structures can create 200-meter

  1. Labile aluminium chemistry downstream a limestone treated lake and an acid tributary: effects of warm winters and extreme rainstorms.

    PubMed

    Andersen, Dag O

    2006-08-01

    The outlet from the limestone treated Lake Terjevann consisted mainly of well-mixed lake water (mean pH 6.1) during the ice-free seasons including the unusually warm winters of 1992 and 1993. However, during the ice-covered period acidic water (mean pH 4.8, mean inorganic aluminium (Al(i)) about 160 microg/l) from the catchment draining under the lake ice dominated. A downstream tributary was generally acid and rich in aluminium (mean pH 4.6, Al(i) about 230 microg/l). After an extreme rainstorm loaded with sea-salts cation exchange in the soil resulted in more than a doubling of the Al(i) concentration (reaching about 500 microg/l). It took 3-4 months until the Al(i) concentration returned to pre-event levels. During the ice-covered period, the acidic outlet and tributary waters resulted in acidic conditions below the confluence (pH<4.8, Al(i) about 150 microg/l) while during the ice-free periods the more neutral outlet water resulted in higher pH and lower Al(i) concentrations (pH>5.2, Al(i) about 95 microg/l). However, during the latter climatic conditions the water was most probably more harmful to fish due to hydrolysing and polymerizing aluminium. After the sea-salt event, the increased Al(i) concentration in the tributary made the zone below the confluence potentially more toxic (pH approximately 5, Al(i) approximately 250 microg/l). Expected global warming resulting in winter mean temperatures above 0 degrees C may eliminate the seasonal acidification of the outlet from limestone-treated lakes creating permanent toxic mixing zones in the confluence below acidic aluminium-rich tributaries. Besides, more frequent rainstorms as a consequence of global warming may increase the frequency of sea-salt events and the Al(i) concentrations in the mixing zones.

  2. Labile aluminium chemistry downstream a limestone treated lake and an acid tributary: effects of warm winters and extreme rainstorms.

    PubMed

    Andersen, Dag O

    2006-08-01

    The outlet from the limestone treated Lake Terjevann consisted mainly of well-mixed lake water (mean pH 6.1) during the ice-free seasons including the unusually warm winters of 1992 and 1993. However, during the ice-covered period acidic water (mean pH 4.8, mean inorganic aluminium (Al(i)) about 160 microg/l) from the catchment draining under the lake ice dominated. A downstream tributary was generally acid and rich in aluminium (mean pH 4.6, Al(i) about 230 microg/l). After an extreme rainstorm loaded with sea-salts cation exchange in the soil resulted in more than a doubling of the Al(i) concentration (reaching about 500 microg/l). It took 3-4 months until the Al(i) concentration returned to pre-event levels. During the ice-covered period, the acidic outlet and tributary waters resulted in acidic conditions below the confluence (pH<4.8, Al(i) about 150 microg/l) while during the ice-free periods the more neutral outlet water resulted in higher pH and lower Al(i) concentrations (pH>5.2, Al(i) about 95 microg/l). However, during the latter climatic conditions the water was most probably more harmful to fish due to hydrolysing and polymerizing aluminium. After the sea-salt event, the increased Al(i) concentration in the tributary made the zone below the confluence potentially more toxic (pH approximately 5, Al(i) approximately 250 microg/l). Expected global warming resulting in winter mean temperatures above 0 degrees C may eliminate the seasonal acidification of the outlet from limestone-treated lakes creating permanent toxic mixing zones in the confluence below acidic aluminium-rich tributaries. Besides, more frequent rainstorms as a consequence of global warming may increase the frequency of sea-salt events and the Al(i) concentrations in the mixing zones. PMID:16269168

  3. Source characterization of sedimentary organic matter using molecular and stable carbon isotopic composition of n-alkanes and fatty acids in sediment core from Lake Dianchi, China.

    PubMed

    Fang, Jidun; Wu, Fengchang; Xiong, Yongqiang; Li, Fasheng; Du, Xiaoming; An, Da; Wang, Lifang

    2014-03-01

    The distribution and compound-specific carbon isotope ratios of n-alkanes and fatty acids in a sediment core (63 cm) collected from Lake Dianchi were examined to investigate organic matter sources in the eutrophic lake. Fatty acids included free and bound fatty acids. The carbon isotope compositions of individual n-alkanes and fatty acids from Lake Dianchi sediments were determined using gas chromatography/isotope ratio mass spectrometry (GC-IRMS). The δ(13)C values of individual n-alkanes (C16-C31) varied between -24.1‰ and -35.6‰, suggesting a dominance of (13)C-depleted n-alkanes that originated from C3 plants and lacustrine algae. Fatty acids from the sediment extracts were analyzed for their abundances and carbon isotopic compositions. Molecular and isotopic evidence indicates that most of the short-chain fatty acids from Lake Dianchi sediment extracts are sourced from intense microbial recycling and resynthesis of organic matter. Long-chain free fatty acids are mainly derived from terrestrial sources. However, long-chain bound fatty acids are sourced from a combination of terrestrial organic matter, bacteria and algae, with the contribution from algal sources higher in the hypereutrophic stage.

  4. Effects of different cooking methods on fatty acid profiles in four freshwater fishes from the Laurentian Great Lakes region.

    PubMed

    Neff, Margaret R; Bhavsar, Satyendra P; Braekevelt, Eric; Arts, Michael T

    2014-12-01

    Fish is often promoted as a healthy part of the human diet due its high content of long chain n-3 polyunsaturated fatty acids (LC-PUFA). Previous studies have shown that cooked fish can have different fatty acid profiles than raw fillets, depending on the cooking method and fish species. In this study, the fatty acid content of broiled, baked or fried skinless, boneless fillets of four fish species from the tributaries of the Great Lakes, or connecting rivers, was compared to fatty acid profiles in raw sections from the same fillet. Cooking treatments had little effect on n-3 fatty acid content; however, fried treatments generally had higher n-6 and MUFA content, which is likely a result of the cooking oil used (canola). Broiling or baking is generally the most healthy option presented in this study, as these methods result in lower levels of less-favourable fatty acids; however, the choice of cooking oil may also influence the overall fatty acid content in cooked fish.

  5. Determining D/L Ratios of Amino Acids Found in Ice Above Lake Vostok Using ESI/CIT Mass Spectroscopy

    NASA Technical Reports Server (NTRS)

    Tsapin, A.; Kanik, I.; Beegle, L. W.; Wu, L.; Cooks, R. G.

    2003-01-01

    Astrobiology is an area where longevity of (micro) organisms is of great interest. Cryospheres are common phenomena in the solar system, particularly on satellites, comets and asteroids, as well as at least some of the planets. Recent data from the Mars Global Surveyor mission suggest the possibility of permafrost or perhaps even liquid water under the Martian surface [2]. These environments may be the areas in which the probability of finding life is the highest. This issue is of concern due to the probable evolution of planetary environments such as that of Mars from more hospitable to less hospitable conditions over the history of the solar system. In addition, evaluation of the possible transfer of living organisms between planets via impact ejecta [3] is dependent on knowledge of the maximum time periods over which microorganisms can remain dormant and subsequently revive and reproduce.Amino acid racemization dating, or aminostratigraphy, has been used for many years to date biological systems, and has been examined as a possible biosignature detection technique for Mars. We have suggested using amino acid racemization as one of the most indicative biosignatures [4]. Only life systems produce preferential synthesis of L-amino acids versus D-amino acids. Almost all amino acids in terrestrial organisms can be found only in the L-enantiomeric form.We studied the level of amino acid racemization, specifically of aspartic acid, in permafrost samples from eastern Siberia. Also we analyzed samples of ice from borehole drilled to lake Vostok, Antarctica.

  6. Syntrophic associations from hypersaline soda lakes converting organic acids and alcohols to methane at extremely haloalkaline conditions.

    PubMed

    Sorokin, Dimitry Y; Abbas, Ben; Geleijnse, Mitchell; Kolganova, Tatjana V; Kleerebezem, Robbert; van Loosdrecht, Mark C M

    2016-09-01

    Until now anaerobic oxidation of VFA at high salt-pH has been demonstrated only at sulfate-reducing conditions. Here, we present results of a microbiological investigation of anaerobic conversion of organic acids and alcohols at methanogenic conditions by syntrophic associations enriched from hypersaline soda lakes in Central Asia. Sediment incubation experiments showed active, albeit very slow, methane formation from acetate, propionate, butyrate and C2 C4 alcohols at pH 10 and various levels of salinity. Enrichments of syntrophic associations using hydrogenotrophic members of the genus Methanocalculus from soda lakes as partners resulted in several highly enriched cultures converting acetate, propionate, butyrate, benzoate and EtOH to methane. Most syntrophs belonged to Firmicutes, while the propionate-oxidizer formed a novel lineage within the family Syntrophobacteraceae in the Deltaproteobacteria. The acetate-oxidizing syntroph was identified as 'Ca. Syntrophonatronum acetioxidans' previously found to oxidize acetate at sulfate-reducing conditions up to salt-saturating concentrations. Butyrate and a benzoate-degrading syntrophs represent novel genus-level lineages in Syntrophomonadales which are proposed as Candidatus taxons 'Syntrophobaca', 'Syntrophocurvum' and 'Syntropholuna'. Overall, despite very slow growth, the results indicated the presence of a functionally competent syntrophic community in hypersaline soda lakes, capable of efficient oxidation of fermentation products to methane at extremely haloalkaline conditions. PMID:27387660

  7. Diet of yellow-billed loons (Gavia adamsii) in Arctic lakes during the nesting season inferred from fatty acid analysis

    USGS Publications Warehouse

    Haynes, T B; Schmutz, Joel A.; Bromaghin, Jeffrey; Iverson, S J; Padula, V M; Rosenberger, A E

    2015-01-01

    Understanding the dietary habits of yellow-billed loons (Gavia adamsii) can give important insights into their ecology, however, studying the diet of loons is difficult when direct observation or specimen collection is impractical. We investigate the diet of yellow-billed loons nesting on the Arctic Coastal Plain of Alaska using quantitative fatty acid signature analysis. Tissue analysis from 26 yellow-billed loons and eleven prey groups (nine fish species and two invertebrate groups) from Arctic lakes suggests that yellow-billed loons are eating high proportions of Alaska blackfish (Dallia pectoralis), broad whitefish (Coregonus nasus) and three-spined stickleback (Gasterosteus aculeatus) during late spring and early summer. The prominence of blackfish in diets highlights the widespread availability of blackfish during the early stages of loon nesting, soon after spring thaw. The high proportions of broad whitefish and three-spined stickleback may reflect a residual signal from the coastal staging period prior to establishing nesting territories on lakes, when loons are more likely to encounter these species. Our analyses were sensitive to the choice of calibration coefficient based on data from three different species, indicating the need for development of loon-specific coefficients for future study and confirmation of our results. Regardless, fish that are coastally distributed and that successfully overwinter in lakes are likely key food items for yellow-billed loons early in the nesting season.

  8. Syntrophic associations from hypersaline soda lakes converting organic acids and alcohols to methane at extremely haloalkaline conditions.

    PubMed

    Sorokin, Dimitry Y; Abbas, Ben; Geleijnse, Mitchell; Kolganova, Tatjana V; Kleerebezem, Robbert; van Loosdrecht, Mark C M

    2016-09-01

    Until now anaerobic oxidation of VFA at high salt-pH has been demonstrated only at sulfate-reducing conditions. Here, we present results of a microbiological investigation of anaerobic conversion of organic acids and alcohols at methanogenic conditions by syntrophic associations enriched from hypersaline soda lakes in Central Asia. Sediment incubation experiments showed active, albeit very slow, methane formation from acetate, propionate, butyrate and C2 C4 alcohols at pH 10 and various levels of salinity. Enrichments of syntrophic associations using hydrogenotrophic members of the genus Methanocalculus from soda lakes as partners resulted in several highly enriched cultures converting acetate, propionate, butyrate, benzoate and EtOH to methane. Most syntrophs belonged to Firmicutes, while the propionate-oxidizer formed a novel lineage within the family Syntrophobacteraceae in the Deltaproteobacteria. The acetate-oxidizing syntroph was identified as 'Ca. Syntrophonatronum acetioxidans' previously found to oxidize acetate at sulfate-reducing conditions up to salt-saturating concentrations. Butyrate and a benzoate-degrading syntrophs represent novel genus-level lineages in Syntrophomonadales which are proposed as Candidatus taxons 'Syntrophobaca', 'Syntrophocurvum' and 'Syntropholuna'. Overall, despite very slow growth, the results indicated the presence of a functionally competent syntrophic community in hypersaline soda lakes, capable of efficient oxidation of fermentation products to methane at extremely haloalkaline conditions.

  9. Collapse Pits in Bernard Crater

    NASA Technical Reports Server (NTRS)

    2004-01-01

    [figure removed for brevity, see original site]

    We will be looking at collapse pits for the next two weeks. Collapse pits on Mars are formed in serveral ways. In volcanic areas, channelized lava flows can form roofs which insulate the flowing lava. These features are termed lava tubes on Earth and are common features in basaltic flows. After the lava has drained, parts of the roof of the tube will collapse under its own weight. These collapse pits will only be as deep as the bottom of the original lava tube. Another type of collapse feature associated with volcanic areas arises when very large eruptions completely evacuate the magma chamber beneath the volcano. The weight of the volcano will cause the entire ediface to subside into the void space below it. Structural features including fractures and graben will form during the subsidence. Many times collapse pits will form within the graben. In addition to volcanic collapse pits, Mars has many collapse pits formed when volatiles (such as subsurface ice) are released from the surface layers. As the volatiles leave, the weight of the surrounding rock causes collapse pits to form.

    These pits occur in the floor of Bernard Crater. These collapse pits were likely formed by the release of volatiles from the materials deposited in the crater floor.

    Image information: VIS instrument. Latitude -24, Longitude 205.5 East (154.5 West). 19 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission

  10. Mycosporine-like amino acids in planktonic organisms living under different UV exposure conditions in Patagonian lakes.

    PubMed

    Tartarotti, Barbara; Baffico, Gustavo; Temporetti, Pedro; Zagarese, Horacio E

    2004-07-01

    Mycosporine-like amino acids (MAAs) were studied in zooplankton from 13 Argentinian lakes covering a broad range in altitude, maximum depth and physico-chemical properties of the water. Four to nine different MAAs (predominantly porphyra-334 and shinorine) were found in the copepods Boeckella gibbosa, B. gracilipes, B. meteoris and Parabroteas sarsi, and in the ciliate Stentor amethystinus, while MAAs were undetectable in the cladoceran Daphnia middendorffiana. Among the different copepods, maximum MAA concentrations accounted for 0.25-1.31% of the dry weight, and contents were generally about three to seven times (up to 43 times) higher in the animals living in the clearest lakes compared to those occurring in low-UV systems. This variability in the content of MAAs was related to the lake altitude (r(2) = 0.71), and the fraction of the water column to which 1% of the surface UV radiation at 320 nm penetrated (r(2) = 0.57). Our data therefore underscore the role of MAAs as sunscreens to decrease the potential negative effects of solar radiation, but they also indicate that other environmental factors besides UV transparency play a role in determining MAA concentrations. One lake was selected to obtain additional information on the qualitative composition of MAAs in seston of <100 μm between two sampling sites and over a 2 month study period (austral summer). Six different MAAs were detected in the samples, with porphyra-334 and palythine being predominant. In the copepods collected simultaneously, there was low variation in MAA concentrations between the two sites and over time. Thus, our results suggest that under similar UV exposure conditions MAA contents of planktonic organisms show low temporal variation. PMID:21258622

  11. Mycosporine-like amino acids in planktonic organisms living under different UV exposure conditions in Patagonian lakes

    PubMed Central

    TARTAROTTI, BARBARA; BAFFICO, GUSTAVO; TEMPORETTI, PEDRO; ZAGARESE, HORACIO E.

    2011-01-01

    Mycosporine-like amino acids (MAAs) were studied in zooplankton from 13 Argentinian lakes covering a broad range in altitude, maximum depth and physico-chemical properties of the water. Four to nine different MAAs (predominantly porphyra-334 and shinorine) were found in the copepods Boeckella gibbosa, B. gracilipes, B. meteoris and Parabroteas sarsi, and in the ciliate Stentor amethystinus, while MAAs were undetectable in the cladoceran Daphnia middendorffiana. Among the different copepods, maximum MAA concentrations accounted for 0.25–1.31% of the dry weight, and contents were generally about three to seven times (up to 43 times) higher in the animals living in the clearest lakes compared to those occurring in low-UV systems. This variability in the content of MAAs was related to the lake altitude (r2 = 0.71), and the fraction of the water column to which 1% of the surface UV radiation at 320 nm penetrated (r2 = 0.57). Our data therefore underscore the role of MAAs as sunscreens to decrease the potential negative effects of solar radiation, but they also indicate that other environmental factors besides UV transparency play a role in determining MAA concentrations. One lake was selected to obtain additional information on the qualitative composition of MAAs in seston of <100 μm between two sampling sites and over a 2 month study period (austral summer). Six different MAAs were detected in the samples, with porphyra-334 and palythine being predominant. In the copepods collected simultaneously, there was low variation in MAA concentrations between the two sites and over time. Thus, our results suggest that under similar UV exposure conditions MAA contents of planktonic organisms show low temporal variation. PMID:21258622

  12. Monitoring the results of Canada/U.S.A. acid rain control programs: some lake responses.

    PubMed

    Jeffries, D S; Brydges, T G; Dillon, P J; Keller, W

    2003-01-01

    Aquatic acidification by deposition of airborne pollutants emerged as an environmental issue in southeastern Canada during the 1970s. Drawing information from the extensive research and monitoring programs, a sequence of issue assessments demonstrated the necessity of reducing the anthropogenic emissions of acidifying pollutants, particularly sulphur dioxide (SO2). The 1991 Canada-U.S. Air Quality Agreement (AQA) was negotiated to reduce North American SO2 emissions by approximately 40% relative to 1980 levels by 2010, and at present, both countries have reduced emissions beyond their AQA commitment. In response to reduced SO2 emissions, atmospheric deposition of sulphate (SO4(2-)) and SO4(2-) concentrations in many lakes have declined, particularly in south-central Ontario and southern Québec. Sulphate deposition still exceeds aquatic critical loads throughout southeastern Canada however. Increasing pH or alkalinity (commonly deemed 'recovery') has been observed in only some lakes. Several biogeochemical factors have intervened to modify the lake chemistry response to reduced SO4(2-) input, notably release of stored SO4(2-) from wetlands following periods of drought and reduction in the export of base cations from terrestrial soils. Three examples from Ontario are presented to illustrate these responses. Significant increases in pH and alkalinity have been observed in many lakes in the Sudbury area of Ontario due to the large reductions in local SO2 emissions; 'early-stage' biological recovery is evident in these lakes. An integrated assessment model predicts that AQA emission reductions will not be sufficient to promote widespread chemical or biological recovery of Canadian lakes. Monitoring and modeling are mutually supporting assessment activities and both must continue.

  13. Use of tracers to quantify subsurface flow through a mining pit.

    PubMed

    Schladow, S Geoffrey; Clark, Jordan F

    2008-12-01

    Three independent tracer experiments were conducted to quantify the through-flow of water from Herman Pit, an abandoned mercury (Hg) mine pit adjacent to Clear Lake, California, USA. The tracers used were Rhodamine-WT, sulfur hexafluoride, and a mixture of sulfur hexafluoride and neon-22. The tracers were injected into Herman Pit, a generally well-mixed water body of approximately 81,000 m2, and the concentrations were monitored in the mine pit, observation wells, and the lake for 2-3 months following each injection. The results for all three experiments showed that the tracer arrived at certain observation wells within days of injection. Comparing all the well data showed a highly heterogeneous response, with a small number of wells showing this near-instantaneous response and others taking months before the tracer was detectable. Tracer was also found in the lake on four occasions over a one-month period, too few to infer any pattern but sufficient to confirm the connection of the two water bodies. Using a simple mass balance model it was possible to determine the effective loss rate through advection for each of the tracers and with this to estimate the through-flow rate. The through-flow rate for all three experiments was approximately 630 L/s, at least 1-2 orders of magnitude larger than previous estimates, all of which had been based on geochemical inferences or other indirect measures of the pit through-flow.

  14. Chemical composition of organic matter in extremely acid, lignite-containing lake sediments impacted by fly ash contamination.

    PubMed

    Chabbi, A; Rumpel, C

    2004-01-01

    In the Lusatian lignite mining district of eastern Germany, extremely acid lakes developed during ground water rising after exploitation of lignite in open-cast mines. The reasons of plant colonization (Juncus bulbosus L.) of some lakes exhibiting moderate pH values while others remain extremely acid and unvegetated are unknown. Alkalinity gain may be achieved by addition of alkaline materials and/or decomposition of organic matter. Our objective was to examine fly ash deposition and the resulting changes in organic matter composition in the uppermost 0 to 5 cm of the sediment sampled from vegetated and unvegetated lakes. Bulk soil and particle size fractions were analyzed for elemental composition, magnetic susceptibility, and chemical structure of the organic matter by 13C solid-state nuclear magnetic resonance (NMR) spectroscopy. The lignite content of the samples was estimated by 14C activity measurements. The pH values decreased with increasing depth and the changes in pH were found to be correlated with changes in magnetic susceptibility. Carbon and nitrogen contents were found to decrease with increasing depth. The C to N ratios are consistent with the (i) the presence of decomposing plant residues and/or microbial material such as algae in the upper 0 to 5 cm of the sediment and (ii) the dominance of lignite in the layers below this depth as confirmed by 14C activity measurements. The structural analyses of the particle size separates from the 0- to 5-cm depth were consistent with the presence of organic matter derived from plant material. This study confirms that fly ash is an important source of alkalinity in the upper 0 to 5 cm of the sediment that enhanced plant growth and led to enrichment of the sediment with organic matter derived from plant material. PMID:15074815

  15. Great Minds? Great Lakes!

    ERIC Educational Resources Information Center

    Environmental Protection Agency, Chicago, IL. Great Lakes National Program Office.

    This book contains lesson plans that provide an integrated approach to incorporating Great Lakes environmental issues into elementary subjects. The book is divided into three subject areas: (1) History, which includes the origins of the Great Lakes, Great Lakes people, and shipwrecks; (2) Social Studies, which covers government, acid rain as a…

  16. Insights from the Metagenome of an Acid Salt Lake: The Role of Biology in an Extreme Depositional Environment

    PubMed Central

    Johnson, Sarah Stewart; Chevrette, Marc Gerard; Ehlmann, Bethany L.; Benison, Kathleen Counter

    2015-01-01

    The extremely acidic brine lakes of the Yilgarn Craton of Western Australia are home to some of the most biologically challenging waters on Earth. In this study, we employed metagenomic shotgun sequencing to generate a microbial profile of the depositional environment associated with the sulfur-rich sediments of one such lake. Of the 1.5 M high-quality reads generated, 0.25 M were mapped to protein features, which in turn provide new insights into the metabolic function of this community. In particular, 45 diverse genes associated with sulfur metabolism were identified, the majority of which were linked to either the conversion of sulfate to adenylylsulfate and the subsequent production of sulfide from sulfite or the oxidation of sulfide, elemental sulfur, and thiosulfate via the sulfur oxidation (Sox) system. This is the first metagenomic study of an acidic, hypersaline depositional environment, and we present evidence for a surprisingly high level of microbial diversity. Our findings also illuminate the possibility that we may be meaningfully underestimating the effects of biology on the chemistry of these sulfur-rich sediments, thereby influencing our understanding of past geobiological conditions that may have been present on Earth as well as early Mars. PMID:25923206

  17. Insights from the metagenome of an acid salt lake: the role of biology in an extreme depositional environment.

    PubMed

    Johnson, Sarah Stewart; Chevrette, Marc Gerard; Ehlmann, Bethany L; Benison, Kathleen Counter

    2015-01-01

    The extremely acidic brine lakes of the Yilgarn Craton of Western Australia are home to some of the most biologically challenging waters on Earth. In this study, we employed metagenomic shotgun sequencing to generate a microbial profile of the depositional environment associated with the sulfur-rich sediments of one such lake. Of the 1.5 M high-quality reads generated, 0.25 M were mapped to protein features, which in turn provide new insights into the metabolic function of this community. In particular, 45 diverse genes associated with sulfur metabolism were identified, the majority of which were linked to either the conversion of sulfate to adenylylsulfate and the subsequent production of sulfide from sulfite or the oxidation of sulfide, elemental sulfur, and thiosulfate via the sulfur oxidation (Sox) system. This is the first metagenomic study of an acidic, hypersaline depositional environment, and we present evidence for a surprisingly high level of microbial diversity. Our findings also illuminate the possibility that we may be meaningfully underestimating the effects of biology on the chemistry of these sulfur-rich sediments, thereby influencing our understanding of past geobiological conditions that may have been present on Earth as well as early Mars.

  18. Long term response of acid-sensitive Vermont Lakes to sulfate deposition

    EPA Science Inventory

    Atmospheric deposition of sulfur can negatively affect the health of lakes and streams, particularly in poorly buffered catchments. In response to the Clean Air Act Amendments, wet deposition of sulfate decreased more than 35% in Vermont between 1990 and 2008. However, most of ...

  19. Design considerations for ozone and acid aerosol exposure and health investigations: the Fairview Lake summer camp - photochemical smog case study

    SciTech Connect

    Lioy, P.J.; Spektor, D.; Thurston, G.; Citak, K.; Lippmann, M.; Bock, N.; Speizer, F.E.; Hayes, C.

    1987-01-01

    The health effects associated with ozone and acidic particulate sulfate exposures to active children have been and are being addressed in field epidemiological studies at summer camps in rural areas of the Northeastern US. The rationale and study design for studies, which have been conducted in Pennsylvania and New Jersey, are developed and reviewed. As background, results are summarized for human clinical and epidemiological studies and animal studies. These provided the basis for selection of health outcomes measured results from chemical characterization and transport studies are reviewed to define the criteria used for selection of a site which is effected by high ozone and acid species during photochemical smog episodes. The integration of the study design is discussed in detail by reviewing its application to the 1984 - Fairview Lake Camp Study (July 8 to August 4). The features of the camp study are reviewed, including the study population, pulmonary function procedures and analyses, air pollution monitoring instrumentation, and the site characteristics. The pollution exposure data are presented, for ozone and acidic sulfates and examined for the range and distribution concentration. Further information is provided on the intensity and duration of episodes encountered over the course of the study. Episodes occurred which had ozone and acid sulfates, ozone alone, and acid sulfates alone. 56 references, 9 figures.

  20. The use of amino acid analyses in (palaeo-) limnological investigations: A comparative study of four Indian lakes in different climate regimes

    NASA Astrophysics Data System (ADS)

    Menzel, Philip; Anupama, Krishnamurthy; Basavaiah, Nathani; Das, Brijraj Krishna; Gaye, Birgit; Herrmann, Nicole; Prasad, Sushma

    2015-07-01

    In the present study, we report the results of comprehensive amino acid (AA) analyses of four Indian lakes from different climate regimes. We focus on the investigation of sediment cores retrieved from the lakes but data of modern sediment as well as vascular plant, soil, and suspended particulate matter samples from individual lakes are also presented. Commonly used degradation and organic matter source indices are tested for their applicability to the lake sediments, and we discuss potential reasons for possible limitations. A principal component analysis including the monomeric AA composition of organic matter of all analysed samples indicates that differences in organic matter sources and the environmental properties of the individual lakes are responsible for the major variability in monomeric AA distribution of the different samples. However, the PCA also gives a factor that most probably separates the samples according to their state of organic matter degradation. Using the factor loadings of the individual AA monomers, we calculate a lake sediment degradation index (LI) that might be applicable to other palaeo-lake investigations.

  1. Calcite growth-rate inhibition by fulvic acids isolated from Big Soda Lake, Nevada, USA, The Suwannee River, Georgia, USA and by polycarboxylic acids

    USGS Publications Warehouse

    Reddy, Michael M.; Leenheer, Jerry

    2011-01-01

    Calcite crystallization rates are characterized using a constant solution composition at 25°C, pH=8.5, and calcite supersaturation (Ω) of 4.5 in the absence and presence of fulvic acids isolated from Big Soda Lake, Nevada (BSLFA), and a fulvic acid from the Suwannee River, Georgia (SRFA). Rates are also measured in the presence and absence of low-molar mass, aliphatic-alicyclic polycarboxylic acids (PCA). BSLFA inhibits calcite crystal-growth rates with increasing BSLFA concentration, suggesting that BSLFA adsorbs at growth sites on the calcite crystal surface. Calcite growth morphology in the presence of BSLFA differed from growth in its absence, supporting an adsorption mechanism of calcite-growth inhibition by BSLFA. Calcite growth-rate inhibition by BSLFA is consistent with a model indicating that polycarboxylic acid molecules present in BSLFA adsorb at growth sites on the calcite crystal surface. In contrast to published results for an unfractionated SRFA, there is dramatic calcite growth inhibition (at a concentration of 1 mg/L) by a SRFA fraction eluted by pH 5 solution from XAD-8 resin, indicating that calcite growth-rate inhibition is related to specific SRFA component fractions. A cyclic PCA, 1, 2, 3, 4, 5, 6-cyclohexane hexacarboxylic acid (CHXHCA) is a strong calcite growth-rate inhibitor at concentrations less than 0.1 mg/L. Two other cyclic PCAs, 1, 1 cyclopentanedicarboxylic acid (CPDCA) and 1, 1 cyclobutanedicarboxylic acid (CBDCA) with the carboxylic acid groups attached to the same ring carbon atom, have no effect on calcite growth rates up to concentrations of 10 mg/L. Organic matter ad-sorbed from the air onto the seed crystals has no effect on the measured calcite crystal-growth rates.

  2. Quantitative damage evaluation of localized deep pitting

    SciTech Connect

    Al Beed, A.A.; Al Garni, M.A.

    2000-04-01

    Localized deep pitting is considered difficult to precisely measure and evaluate using simple techniques and daily-use analysis approaches. A case study was made of carbon steel heat exchangers in a typical fresh cooling water environment that experienced severe pitting. To effectively and precisely evaluate the encountered pitting damage, a simple measurement and analyses approach was devised. In this article, the pitting measurement technique and the damage evaluation approach are presented and discussed in detail.

  3. Impacts of changing food webs in Lake Ontario: Implications of dietary fatty acids on growth of alewives

    USGS Publications Warehouse

    Snyder, R.J.; Demarche, C.J.; Honeyfield, D.C.

    2011-01-01

    Declines in the abundance and condition of Great Lakes Alewives have been reported periodically during the last two decades, and the reasons for these declines remain unclear. To better understand how food web changes may influence Alewife growth and Wisconsin growth model predictions, we fed Alewives isocaloric diets high in omega-6 fatty acids (corn oil) or high in omega-3 fatty acids (fish oil). Alewives were fed the experimental diets at either 1% ("low ration") or 3% ("high ration") of their wet body weight per day. After six weeks, Alewives maintained on the high ration diets were significantly larger than those fed the low ration diets. Moreover, Alewives given the high ration fish oil diet were significantly larger than those maintained on the high ration corn oil diet after six weeks of growth. Body lipid, energy density and total body energy of Alewives on the high ration diets were significantly higher than those fed the low ration diets, and total body energy was significantly higher in Alewives given the high ration fish oil diet compared to those on the high ration corn oil diet. The current Wisconsin bioenergetics model underestimated growth and overestimated food consumption by Alewives in our study. Alewife thiaminase activity was similar among treatment groups. Overall, our results suggest that future food web changes in Lake Ontario, particularly if they involve decreases in the abundance of lipid rich prey items such as Mysis, may reduce Alewife growth rates and total body energy due to reductions in the availability of dietary omega-3 fatty acids. ?? 2011 AEHMS.

  4. Sediment amino acids as indicators of anthropogenic activities and potential environmental risk in Erhai Lake, Southwest China.

    PubMed

    Ni, Zhaokui; Wang, Shengrui; Zhang, Mianmian

    2016-05-01

    Total hydrolysable amino acids (THAAs) constitute the most important fraction of labile nitrogen. Anthropogenic activities directly influence various biogeochemical cycles and then accelerate lake ecosystem deterioration. This is the first study that has established the relationship between sediment THAAs and anthropogenic activities using dated sediment cores, and evaluated the possibility of THAAs release at the sediment interface based on changes in environmental conditions in Erhai Lake. The results showed that historical distribution and fractions of THAAs could be divided into three stages: a stable period before the 1970s, a clear increasing period from the 1970s to 1990s, and a gradually steady period that started after the 1990s. The chemical fraction, aromatic and sulfur amino acids (AAs) accounted for only ≤3% of THAAs. Basic AAs accounted for 5-17% of THAAs, and remained at a relatively stable level. However, acidic and neutral AAs, which accounted for 19-44% and 35-69% of THAAs, respectively, were the predominant factors causing THAAs to increase due to rapid agricultural intensification and intensification of contemporary sedimentation of phytoplankton or macrophytes since the 1970s. These trends were closely related to both anthropogenic activities and natural processes, which implied that sediment THAAs could act as an effective indicator that reflects anthropogenic activities and aquatic environmental characteristics. The current contributions of sediment THAAs on TN and TOC were <5% and 1.5%, respectively. However, the dramatic increase in THAAs in the sediment cores indicated that there was a huge potential source of labile nitrogen for the overlying water under certain environmental conditions. Correlation analysis suggested that the release of THAAs was negatively correlated with pH, whereas positively correlated with bacterial number and degree of OM mineralization, which particularly depend on the stability of HFOM. Therefore, the risk of

  5. 29. (Credit JTL) Low service pump pit in background erected ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    29. (Credit JTL) Low service pump pit in background erected in 1911-1912 on the banks of Cross Bayou (a Worthington compound duplex steam engine was placed inside this structure.) In the foreground is the receiving well (also erected in 1911-1912) which received water from the Red River siphon. After 1926 this well received water, instead, from Cross Lake via a 30-inch conduit. A concrete platform was installed in 1960 for #6 electric low service pump which has been superceded by newer 1977 installation. - McNeil Street Pumping Station, McNeil Street & Cross Bayou, Shreveport, Caddo Parish, LA

  6. NIR detection of pits and pit fragments in fresh cherries (abstract)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The feasibility of using near infrared (NIR) diffuse reflectance spectroscopy for the detection of pits and pit fragments in cherries was demonstrated. For detection of whole pits, 300 cherries were obtained locally and pits were removed from half. NIR reflectance spectra were obtained in triplicate...

  7. Workshop Proceedings: Pitting in Steam Generator Tubing

    SciTech Connect

    1984-10-01

    A two-day workshop focused on the probable causes of steam generator pitting at two nuclear plants and on whether pitting is a low-temperature or a high-temperature phenomenon. Participants also heard descriptions of various pit-resistant metals that are suitable for tube sleeving.

  8. New insights into the source of decadal increases of dissolved organic matter in acid-sensitive lakes of the Northeastern U.S.

    EPA Science Inventory

    The last several decades have seen decreases in SO42- deposition across the northeastern United States. As a result, SO42- concentrations in lakes and streams have also decreased and many surface water bodies have become less acidic. During the same time period, there has been ...

  9. Growing spherulitic calcite grains in saline, hyperalkaline lakes: experimental evaluation of the effects of Mg-clays and organic acids

    NASA Astrophysics Data System (ADS)

    Mercedes-Martín, R.; Rogerson, M. R.; Brasier, A. T.; Vonhof, H. B.; Prior, T. J.; Fellows, S. M.; Reijmer, J. J. G.; Billing, I.; Pedley, H. M.

    2016-04-01

    The origin of spherical-radial calcite bodies - spherulites - in sublacustrine, hyperalkaline and saline systems is unclear, and therefore their palaeoenvironmental significance as allochems is disputed. Here, we experimentally investigate two hypotheses concerning the origin of spherulites. The first is that spherulites precipitate from solutions super-saturated with respect to magnesium-silicate clays, such as stevensite. The second is that spherulite precipitation happens in the presence of dissolved, organic acid molecules. In both cases, experiments were performed under sterile conditions using large batches of a synthetic and cell-free solution replicating waters found in hyperalkaline, saline lakes (such as Mono Lake, California). Our experimental results show that a highly alkaline and highly saline solution supersaturated with respect to calcite (control solution) will precipitate euhedral to subhedral rhombic and trigonal bladed calcite crystals. The same solution supersaturated with respect to stevensite precipitates sheet-like stevensite crystals rather than a gel, and calcite precipitation is reduced by ~ 50% compared to the control solution, producing a mixture of patchy prismatic subhedral to euhedral, and minor needle-like, calcite crystals. Enhanced magnesium concentration in solution is the likely the cause of decreased volumes of calcite precipitation, as this raised equilibrium ion activity ratio in the solution. On the other hand, when alginic acid was present then the result was widespread development of micron-size calcium carbonate spherulite bodies. With further growth time, but falling supersaturation, these spherules fused into botryoidal-topped crusts made of micron-size fibro-radial calcite crystals. We conclude that the simplest tested mechanism to deposit significant spherical-radial calcite bodies is to begin with a strongly supersaturated solution that contains specific but environmentally-common organic acids. Furthermore, we found

  10. Effects of acidification on mercury methylation, demethylation, and volatilization in sediments from an acid-susceptible lake.

    PubMed Central

    Steffan, R J; Korthals, E T; Winfrey, M R

    1988-01-01

    The effect of experimental acidification on mercury methylation, demethylation, and volatilization was examined in surficial sediment samples from a weakly buffered northern Wisconsin lake. All mercury transformations were measured with radioisotopic tracers. Acidification of sediment pH with H2SO4, HCl, or HNO3 significantly decreased 203Hg(II) methylation. Acidification of pH 6.1 (ambient) sediments to pH 4.5 with either H2SO4 or HCl inhibited methylation by over 65%. The decreased methylation was due to the increased hydrogen ion concentration because methylation was not affected by concentrations of Na2SO4 or NaCl equimolar to the amount of acid added. Inhibition of methylation was observed even after prolonged acidification of sediments to pH 5.0 for up to 74 days. Acidification of sediments to pH 5.5, 4.5, and 3.5 with HNO3 resulted in a near complete inhibition of methylation at each pH. Similarly, the addition of equimolar amounts of NaNO3 resulted in a near complete inhibition of methylation, indicating that the inhibition was due to the nitrate ion rather than to the acidity. Demethylation of methyl mercury was not affected by pHs between 8.0 and 4.4, but sharply decreased below pH 4.4. Volatilization of 203Hg(II) from surface sediments was less than 2% of methylation activity and was not significantly different from that in killed sediments. This study indicated that acidification of sediments inhibits mercury methylation and that the observed increase in the mercury burdens in fish from low pH lakes is not due to increased production of methylmercury in sediments. PMID:3178208

  11. Contemporaneous deposition of phyllosilicates and sulfates: Using Australian acidic saline lake deposits to describe geochemical variability on Mars

    USGS Publications Warehouse

    Baldridge, A.M.; Hook, S.J.; Crowley, J.K.; Marion, G.M.; Kargel, J.S.; Michalski, J.L.; Thomson, B.J.; de Souza, Filho C.R.; Bridges, N.T.; Brown, A.J.

    2009-01-01

    Studies of the origin of the Martian sulfate and phyllosilicate deposits have led to the hypothesis that there was a marked, global-scale change in the Mars environment from circum-neutral pH aqueous alteration in the Noachian to an acidic evaporitic system in the late Noachian to Hesperian. However, terrestrial studies suggest that two different geochemical systems need not be invoked to explain such geochemical variation.Western Australian acidic playa lakes have large pH differences separated vertically and laterally by only a few tens of meters, demonstrating how highly variable chemistries can coexist over short distances in natural environments. We suggest diverse and variable Martian aqueous environments where the coetaneous formation of phyllosilicates and sulfates at the Australian sites are analogs for regions where phyllosilicates and sulfates coexist on Mars. In these systems, Fe and alkali earth phyllosilicates represent deep facies associated with upwelling neutral to alkaline groundwater, whereas aluminous phyllosilicates and sulfates represent near-surface evaporitic facies formed from more acidic brines. Copyright 2009 by the American Geophysical Union.

  12. Fatty Acid Composition and Levels of Selected Polyunsaturated Fatty Acids in Four Commercial Important Freshwater Fish Species from Lake Victoria, Tanzania

    PubMed Central

    Robert, Agnes; Mfilinge, Prosper; Limbu, Samwel M.; Mwita, Chacha J.

    2014-01-01

    Fatty acids (FAs) particularly ω3 and ω6 polyunsaturated fatty acids (PUFAs) play important role in human health. This study aimed to investigate the composition and levels of selected ω3 PUFAs in four commercial fish species, Nile perch (Lates niloticus), Nile tilapia (Oreochromis niloticus), Tilapia zillii, and dagaa (Rastrineobola argentea) from Mwanza Gulf in Lake Victoria. The results indicated that 36 types of FAs with different saturation levels were detected. These FAs were dominated by docosahexaenoic (DHA), eicosapentaenoic (EPA), docosapentaenoic (DPA), and eicosatetraenoic acids. O. niloticus had the highest composition of FAs (34) compared to L. niloticus (27), T. zillii (26), and R. argentea (21). The levels of EPA differed significantly among the four commercial fish species (F = 6.19,  P = 0.001). The highest EPA levels were found in R. argentea followed by L. niloticus and O. niloticus and the lowest in T. zillii. The DPA levels showed no significant difference among the four fish species studied (F = 0.652,  P = 0.583). The study concluded that all four commercial species collected from Mwanza Gulf are good for human health, but R. argentea is the best for consumption because it contains higher levels of ω3 FAs, mainly EPA. PMID:25610654

  13. Interactions among waterfowl, fishes, invertebrates, and macrophytes in four Maine lakes of different acidity

    SciTech Connect

    Hunter, M.L. Jr.; Jones, J.J.; Gibbs, K.E.; Moring, J.R.; Brett, M.

    1985-07-01

    This study addresses the influence of low pH waters on community structure and species interactions on two pairs of oligotrophic, headwater ponds that were physically similar but with markedly different acidities. The circumneutral ponds had fish and the acidic ponds were fishless. The results showed macrophyte species was lower in the acidic ponds possibly due to low pH. Density of backswimmers was greater on the acidic ponds. Tests indicated that the large numbers of backswimmers present on the acidic ponds replaced fish as a significant planktivore. Although macroinvertebrate species differed between acidic and circumneutral ponds, Diptera were the most abundant macroinvertebrates on both sets of ponds. Diptera were the principle item in the diet of brook trout in the circumneutral ponds. Because of the absence of fish in the acidic ponds, this study suggests that a potential competitor of ducks for aquatic foods had been eliminated. Ducklings on the acidic ponds grew faster, spent less time searching, and more time feeding and resting than ducklings on the circumneutral ponds. There was substantial overlap in the diet of trout and ducks, supporting the hypothesis that ducklings and fish compete for invertegrates and that, under certain circumstances, the negative effect of acidification on fish may produce a beneficial effect for ducklings. 3 figs., 30 tabs.

  14. Variation in fatty acid composition in muscle and heart tissues among species and populations of tropical fish in Lakes Victoria and Kyoga.

    PubMed

    Kwetegyeka, Justus; Mpango, George; Grahl-Nielsen, Otto

    2008-11-01

    The composition of the fatty acids in muscle and heart tissue of seven fish species, Nile perch (Lates niloticus), Nile tilapia (Oreochromis niloticus), marbled lungfish (Protopterus aethiopicus), African catfish (Clarias gariepinus), Lake Victoria squeaker (Synodontis victoriae), Bagrus docmas, and Tilapia zilli, from two locations in Lake Kyoga and one location in Lake Victoria was chemometrically determined. The muscle tissue was very lean, with an average of 3.4 mg total fatty acids per g tissue. The lipid level in the heart tissue was approximately five times higher than in the muscle tissue, with an average of 15.5 mg total fatty acids per g tissue. The n-3/n-6 level in the muscles was 1.7 +/- 0.7 and in the heart tissue 1.0 +/- 0.4. The muscle tissue contained an average of 46 mg cholesterol per 100 g, and the heart tissue contained about five times as much. Plasmalogens were detected in 7-8% of the amounts of total fatty acids in both muscle and heart tissue. The seven species had large differences (P < 0.05) in the fatty acid composition for both muscle and heart tissue. Within the species there were differences between fish from the populations in the three locations, although the population differences were smaller than the species differences. These differences appear to be controlled more closely by genetics/transcriptomics than by the diet. PMID:18712426

  15. Impact of acid effluent from Kawah Ijen crater lake on irrigated agricultural soils: Soil chemical processes and plant uptake

    NASA Astrophysics Data System (ADS)

    van Rotterdam-Los, A. M. D.; Heikens, A.; Vriend, S. P.; van Bergen, M. J.; van Gaans, P. F. M.

    2008-12-01

    Volcanogenic contamination of irrigation water, caused by effluent from the hyperacid Ijen crater lake, has severely affected the properties of agricultural soils in East Java, Indonesia. From a comparison of acidified topsoil with subsoil and with top- and subsoil in a reference area, we identified processes responsible for changes in soil and soil solution chemistry induced by acid irrigation water, with emphasis on the nutrients Ca, Mg, Fe, and Mn, and on Al, which may become phytotoxic under acid conditions in soils. Compositional data for bulk soil composition and selective extractions with 1 M KCl and 0.2 M acid ammonium oxalate are used in a mass balance approach to specify element fluxes, including uptake by rice plants. The results show that input via irrigation water has produced an increase in the total aluminum content in the affected topsoil, which is of the same order of magnitude as the increase in labile Al. High bioavailability of Al, as reflected by concentrations in KCl extracts, is consistent with elevated concentrations observed in rice plants. In contrast, and despite the high input via irrigation water, Ca and Mg concentrations have decreased in all measured soil fractions through dissolution of amorphous phases and minerals, and through competition of Al for adsorption sites on the exchange complex and plant roots. Strong leaching is also evident for Fe and especially Mn. In terms of the overall mass balance of the topsoil, plant uptake of Al, Ca, Fe, Mg and Mn is negligible. If the use of acid irrigation would be stopped and the soil pH were to increase to values above 4.5, the observed phytotoxicity of Al will be halted. However, crops may then become fully dependent on the input from irrigation water or fertilizer for essential elements, due to the previous removal from the topsoil through leaching.

  16. The influence of total organic carbon (TOC) on the relationship between acid neutralizing capacity (ANC) and fish status in Norwegian lakes.

    PubMed

    Lydersen, Espen; Larssen, Thorjørn; Fjeld, Eirik

    2004-06-29

    Acid neutralizing capacity (ANC) is the parameter most commonly used as chemical indicator for fish response to acidification. Empirical relationships between fish status of surface waters and ANC have been documented earlier. ANC is commonly calculated as the difference between base cations ([BC]=[Ca2+]+[Mg2+]+[N+]+[K+]) and strong acid anions ([SAA]=[SO4(2)-]+[NO3-]+[Cl-]). This is a very robust calculation of ANC, because none of the parameters incorporated are affected by the partial pressure of CO2, in contrast to the remaining major ions in waters, pH ([H+]), aluminum ([Aln+]), alkalinity ([HCO3-/CO3(2)-]) and organic anions ([An-]). Here we propose a modified ANC calculation where the permanent anionic charge of the organic acids is assumed as a part of the strong acid anions. In many humic lakes, the weak organic acids are the predominant pH-buffering system. Because a significant amount of the weak organic acids have pK-values<3.0-3.5, these relatively strong acids will permanently be deprotonated in almost all natural waters (i.e. pH>4.5). This means that they will be permanently present as anions, equal to the strong acid inorganic anions, SO4(2)-, NO3- and Cl-. In the literature, natural organic acids are often described as triprotic acids with a low pK1 value. Assuming a triprotic model, we suggest to add 1/3 of the organic acid charge density to the strong acid anions in the ANC calculation. The suggested organic acid adjusted ANC (ANC(OAA)), is then calculated as follows: ANC(OAA)=[BC]-([SAA]+1/3CD*TOC) where TOC is total organic carbon (mg C L(-1)), and CD=10.2 is charge density of the organic matter (microeq/mg C), based on literature data from Swedish lakes. ANC(OAA) gives significant lower values of ANC in order to achieve equal fish status compared with the traditional ANC calculation. Using ANC(OAA) the humic conditions in lakes are better taken into account. This may also help explain observations of higher ANC needed to have reproducing fish

  17. Effects of acid deposition on watershed ecosystems of national parks in the great lakes basin.

    PubMed

    Stottlemyer, R; Rutkowski, D; Toczydlowski, D

    1989-04-01

    Legally protected national parks provide an appropriate substrate for essential long-term study of ecosystem structure and function, and for detecting trends in natural and human-induced stress. The absence of unplanned site manipulation in such areas is especially valuable for such research. Our present research has two major components. The first is the long-term ecosystem-level study of the effects of atmospheric contaminants on ecosystem processes. The overall objective is to evaluate ecosystem aquatic/terrestrial linkages and their role in establishing aquatic ecosystem sensitivity to anthropic atmospheric inputs. Four watershed/lake ecosystems, representative of much of the region's diversity, are under study. Two mature boreal sites on Isle Royale are characterized by first-order perennial surface stream input and lake outflow. Two additional mainland northern hardwood sites, one with shallow soils and one with soils derived from glacial till, are characterized by sensitive aquatic systems. One site is in a private reserve and the other in Pictured Rocks National Lakeshore. Surface outflow is gaged by Parshall flume and stage height recorder. Meteorological stations record variables for estimating evapotranspiration. One-tenth ha plots have been established in all watersheds and three sites have had intensive study of precipitation modification by canopy and forest soil. Five-year mean maximum and minimum lake pH varies from 6.85 to 4.94, Ca(2+) from 1070 to 54 μ eq l(-1), K(+) from 5.42 to 8.35 μ eq l(-1), NH 4 (+) from 10.12 to 3.23 μ eq l(-1), HCO 3 (sup-) from 635 to 24 μ eq l(-1), NO 3 (sup-) from 3.27 to 1.54 μ eq l(-1), and SO 4 (sup2-) from 110 to 52.7 μ eq l(-1). The relatively high NO 3 (sup-) values observed in one lake are the result of stream drainage from a watershed dominated by Alnus rugosa, and another has high seasonal NO 3 (sup-) inputs during spring runoff. However, owing to periodic winter thaws, significant snowpack release of

  18. Origin and vertical variation of the bound fatty acids in core sediments of Lake Dianchi in Southwest China.

    PubMed

    Wang, Lifang; Wu, Fengchang; Xiong, Yongqiang; Fang, Jidun

    2013-04-01

    Based on the molecular distribution of bound fatty acid (BFA) compound classes in core sediments of Lake Dianchi combined with the compound-specific δ(13)C values of the straight-chain BFAs, origin and vertical changes of organic matters in the sediments were investigated. The results indicated a significant change of BFA sources over the past 700 years. Contrast to the low concentrations of the terrestrial BFAs, the abundance of BFAs derived from the plankton/bacteria in the top sections (1944-recent) was more than 80%. The increasing proportions of the branched and unsaturated BFAs in total fatty acids were closely correlated with the heavy eutrophication and the frequent algal blooms in the decades. Furthermore, the positive shift of δ (13)C of C16 and C18 (~2‰) in the upper section might be an indicator of the excess phytoplankton productivity. However, it was found that the plankton/bacteria-derived BFAs were more easily degraded during the early diagenetic process. The special compound carbon isotopic compositions of the long straight-chain BFAs (C24 and C26) in the sediments showed a depletion of heavier δ (13)C values (ca. -30‰) in the midsections (1559-1787), reflecting a relatively growing contribution of C3 plants to C4 plants or that C4 plant growth was inhibited in cold and arid climates during the period. PMID:22903813

  19. Factors determining growth and vertical distribution of planktonic algae in extremely acidic mining lakes (pH 2.7)

    NASA Astrophysics Data System (ADS)

    Bissinger, Vera

    2003-04-01

    In this thesis, I investigated the factors influencing the growth and vertical distribution of planktonic algae in extremely acidic mining lakes (pH 2-3). In the focal study site, Lake 111 (pH 2.7; Lusatia, Germany), the chrysophyte, Ochromonas sp., dominates in the upper water strata and the chlorophyte, Chlamydomonas sp., in the deeper strata, forming a pronounced deep chlorophyll maximum (DCM). Inorganic carbon (IC) limitation influenced the phototrophic growth of Chlamydomonas sp. in the upper water strata. Conversely, in deeper strata, light limited its phototrophic growth. When compared with published data for algae from neutral lakes, Chlamydomonas sp. from Lake 111 exhibited a lower maximum growth rate, an enhanced compensation point and higher dark respiration rates, suggesting higher metabolic costs due to the extreme physico-chemical conditions. The photosynthetic performance of Chlamydomonas sp. decreased in high-light-adapted cells when IC limited. In addition, the minimal phosphorus (P) cell quota was suggestive of a higher P requirement under IC limitation. Subsequently, it was shown that Chlamydomonas sp. was a mixotroph, able to enhance its growth rate by taking up dissolved organic carbon (DOC) via osmotrophy. Therefore, it could survive in deeper water strata where DOC concentrations were higher and light limited. However, neither IC limitation, P availability nor in situ DOC concentrations (bottom-up control) could fully explain the vertical distribution of Chlamydomonas sp. in Lake 111. Conversely, when a novel approach was adopted, the grazing influence of the phagotrophic phototroph, Ochromonas sp., was found to exert top-down control on its prey (Chlamydomonas sp.) reducing prey abundance in the upper water strata. This, coupled with the fact that Chlamydomonas sp. uses DOC for growth, leads to a pronounced accumulation of Chlamydomonas sp. cells at depth; an apparent DCM. Therefore, grazing appears to be the main factor influencing the

  20. New explorations along the northern shores of Lake Bonneville

    USGS Publications Warehouse

    Oviatt, Charles G.; Miller, D.M.

    1997-01-01

    This field trip begins in Salt Lake City and makes a clockwise circuit of Great Salt Lake, with primary objectives to observe stratigraphie and geomorphic records of Lake Bonneville. Stops include Stansbury Island, Puddle Valley, gravel pits at Lakeside and the south end of the Hogup Mountains, several stops in Curlew Valley and Hansel Valley, and a final stop at the north end of Great Salt Lake east of the Promontory Mountains. Stratigraphie observations at gravel-pit and natural exposures will be linked to interpretations of lake-level change, which were caused by climate change. Evidence of paleoseismic and volcanic activity will be discussed at several sites, and will be tied to the lacustrine stratigraphic record. The trip provides an overview of the history of Lake Bonneville and introduces participants to some new localities with excellent examples of Lake Bonneville landforms and stratigraphy.

  1. Pitting corrosion of low-Cr austenitic stainless steels

    SciTech Connect

    Bullard, Sophie J.; Covino, Bernard S. Jr.

    1996-01-01

    The Albany Research Center has investigated the pitting corrosion resistance of experimental low-Cr stainless steels and several commercial stainless steels in chloride-containing aqueous and atmospheric environments. Previous research had shown the experimental alloys to be as corrosion resistant as commercial stainless steels in chloride-free acid environments. The alloys studied were Fe-8Cr-16Ni-5.5Si-1Cu-(0-1)Mo, 304 SS, and 316 SS. These alloys were examined by immersion and electrochemical tests in 3.5 wt. pct. NaCl and 6 wt.pct.FeCl{sub 3}. Results of these tests showed that the addition of one weight percent Mo improved the pitting resistance of the low-Cr alloy and that the Mo-containing experimental alloy was as resistant to pitting as the commercial alloys. Electrochemical tests did, however, show the experimental alloys to be slightly less resistant to pitting than the commercial alloys. Because of these results, the low-Cr alloy with one weight percent Mo and 304 SS were exposed for one year to a marine atmospheric environment on the coast of Oregon. The marine atmospheric corrosion resistance of the low-Cr alloy was found to be comparable to that for type 304 stainless steel.

  2. An assessment of hydrogeochemical computer codes applied toward modeling and predicting post-mining pit water geochemistry

    SciTech Connect

    Bird, D.A.; Lyons, W.B. . Hydrology Program); Miller, G.C. . Dept. of Environmental Resource Sciences)

    1993-04-01

    Geochemists for the mining industry utilize a variety of computer codes to model and predict post-mining pit water chemogenesis. This study surveys several of the PC-supported hydrogeochemical codes, applies them to specific open pit mine scenarios, and evaluates their suitability to predicting post-mining pit and groundwater hydro-geochemistry. The prediction of pit water geochemistry is important because of the potential adverse effects of mine drainage, which include acidity, trace metal contamination, pit water stratification, and sludge accumulation. The WATEQ codes of the USGS can calculate speciation and saturation states of a pit water or groundwater sample, but are not designed to model forward rock/water reactions. NETPATH can calculate the chemical mass transfer (inverse modeling) that has occurred during rock/water interaction, but again is not designed to model forward pit water chemogenesis. Several mining industry modelers use EPA's MINTEQA2 code, which has shown to be very flexible with its large database and ability to model adsorption. Reaction path codes, like PHREEQE and EQ3/6, can model reactions on an incremental basis as the pit fills over time, but also may require much user manipulation. New coupled codes like PHREEQM and HYDROGEOCHEM can simulate movement and reaction of groundwater through the aquifer as it approaches and inundates the pit. One aspect of post-mining hydrogeochemical modeling that has received little attention is the effect groundwater will have down gradient after it flows from the pit into the aquifer.

  3. Open-pit equipment notebook

    SciTech Connect

    Not Available

    1984-12-01

    Beds of consolidated material need to be drilled and blasted before successful excavation. In open-pit mining it is common to move fragmented material across to spoil piles by dragline, shovel, or bucketwheel excavator. One method recently introduced uses explosives to throw much of the overburden across the pit, thus reducing the amount of material needing rehandling. The increased cost of explosives must be balanced with the reduced cost of power needed by the prime excavator. The drill hole pattern and the use of high energy explosives require careful design. Making the choice between hydraulic excavators with a backhoe or front shovel, wheel loaders, and rope-operated shovels continues to be an interesting area of debate. While the rope-operated electric shovel is best for large output, smaller shovels are being replaced by hydraulic excavators for numerous reasons. One of the advantages of hydraulic excavators is that they weigh around half that of rope-operated shovels with the same size bucket. Another advantage is their mobility. They can move at a speed roughly twice that of a rope-operated shovel. Hydraulic excavators can successfully attack a solid face that needs blasting before being loaded by a wheel loader or rope-operated shovel. Neither the rope-operated shovel nor the wheel loader has the wrist-action of the hydraulic excavator. The backhoe's ability to dig below the level on which it is situated and to load trucks that are on the pit floor is important. Recently, many equipment manufacturers have introduced microprocessor-controlled systems for higher power and simpler operation. The choice between wheel loaders and hydraulic excavators should be based on site conditions.

  4. Connections between hyper-acid crater lakes and flank springs: new evidence from Rincón de la Vieja volcano (Costa Rica)

    NASA Astrophysics Data System (ADS)

    Martínez, M.; Fernández, E.; Sáenz, W.; van Bergen, M. J.; Ayres, G.; Pacheco, J. F.; Brenes, J.; Avard, G.; Malavassi, E.

    2012-04-01

    Rincón de la Vieja, a complex andesitic stratovolcano in NW Costa Rica, shows various hydrothermal surface manifestations that comprise: (1) A hyper-acid crater lake and subaerial fumaroles receiving direct input of fluids of magmatic origin, (2) Acid thermal discharges along the northeastern slopes of the volcano that feed the headwaters of the Cucaracho river, and (3) Small lakes and a geothermal field with bubbling-boiling mud pools, acid-sulfate springs, steaming ground and fumarolic emissions in a region on the western flank. Here the streams are of relatively low flow rate and their chemical signatures correspond to that of deep fluids from an extensive geothermal reservoir mixed with shallow meteoric water. Physico-chemical properties of the sulfate-chloride hyper-acid lake (T=28-58 °C; pH between 1.2 and <0, high TDS of 24,000-160,000 mg/kg) are consistent with a meteoric water body supplied by a significant input of chemical components derived from hydrolysis of magmatic volatiles and from intense rock leaching. The Cucaracho catchment receives input from warm acid brines with no free-gas phase but carrying a high load of hydrolyzed magmatic volatiles and rock-forming elements. One of these brines (Spring 4) is characterized by a sulfate-chloride chemical signature, medium temperatures of 27-38 °C, pH between 2 and 4 and TDS values between 780 and 1300 mg/L. Based on water and heat-balance considerations, chemical and stable-isotope signatures and groundwater transport modeling, it has been proposed that these acid springs represent brine water from the lake-hydrothermal system that is diluted by shallow groundwater permeating tephra layers (Kempter and Rowe, 2000). Since Rincóńs latest phreatomagmatic activity in 1983, episodes of phreatic eruptions from the crater lake have been registered in 1983-87, 1991, 1995, 1998 and 2011. Some of these eruptions (VEI 1) have expelled large quantities of lake water, triggering small to medium- sized fast

  5. Cause of pitting in beryllium

    SciTech Connect

    Kershaw, R.P.

    1982-04-16

    Light microscopy, bare-film radiography, secondary ion mass spectroscopy, electron microprobe and physical testing were used to examine beryllium specimens exhibiting a stratified, pitted, pattern after chemical milling. The objective was to find the cause of this pattern. Specimens were found to have voids in excess of density specification allowances. These voids are attributed, at least in part, to the sublimation of beryllium fluoride during the vacuum hot pressing operation. The origin of the pattern is attributed to these voids and etching out of fines and associated impurities. Hot isostatic pressing with a subsequent heat treatment close residual porosity and dispersed impurities enough to correct the problem.

  6. Pits and Flutes on Stimpy

    NASA Technical Reports Server (NTRS)

    1997-01-01

    The rock 'Stimpy' is seen in this close-up image taken by the Sojourner rover's left front camera on Sol 70 (September 13). Detailed texture on the rock, such as pits and flutes, are clearly visible.

    Mars Pathfinder is the second in NASA's Discovery program of low-cost spacecraft with highly focused science goals. The Jet Propulsion Laboratory, Pasadena, CA, developed and manages the Mars Pathfinder mission for NASA's Office of Space Science, Washington, D.C. JPL is a division of the California Institute of Technology (Caltech).

  7. Salt Lake City, Utah

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Salt Lake City, Utah, will host the 2002 Winter Olympic Games. The city is located on the southeastern shore of the Great Salt Lake and sits to the west of the Wasatch Mountains, which rise more than 3,500 meters (10,000 feet) above sea level. The city was first settled in 1847 by pioneers seeking relief from religious persecution. Today Salt Lake City, the capital of Utah, is home to more than 170,000 residents. This true-color image of Salt Lake City was acquired by the Enhanced Thematic Mapper Plus (ETM+), flying aboard Landsat 7, on May 26, 2000. The southeastern tip of the Great Salt Lake is visible in the upper left of the image. The furrowed green and brown landscape running north-south is a portion of the Wasatch Mountains, some of which are snow-capped (white pixels). The greyish pixels in the center of the image show the developed areas of the city. A number of water reservoirs can be seen east of the mountain range. Salt Lake City International Airport is visible on the northwestern edge of the city. About 20 miles south of the airport is the Bingham Canyon Copper Mine (tan pixels), the world's largest open pit excavation. See also this MODIS image of Utah. Image courtesy NASA Landsat7 Science Team and USGS Eros Data Center

  8. Differences in activation of aryl hydrocarbon receptors of white sturgeon relative to lake sturgeon are predicted by identities of key amino acids in the ligand binding domain.

    PubMed

    Doering, Jon A; Farmahin, Reza; Wiseman, Steve; Beitel, Shawn C; Kennedy, Sean W; Giesy, John P; Hecker, Markus

    2015-04-01

    Dioxin-like compounds (DLCs) are pollutants of global environmental concern. DLCs elicit their adverse outcomes through activation of the aryl hydrocarbon receptor (AhR). However, there is limited understanding of the mechanisms that result in differences in sensitivity to DLCs among different species of fishes. Understanding these mechanisms is critical for protection of the diversity of fishes exposed to DLCs, including endangered species. This study investigated specific mechanisms that drive responses of two endangered fishes, white sturgeon (Acipenser transmontanus) and lake sturgeon (Acipenser fulvescens) to DLCs. It determined whether differences in sensitivity to activation of AhRs (AhR1 and AhR2) can be predicted based on identities of key amino acids in the ligand binding domain (LBD). White sturgeon were 3- to 30-fold more sensitive than lake sturgeon to exposure to 5 different DLCs based on activation of AhR2. There were no differences in sensitivity between white sturgeon and lake sturgeon based on activation of AhR1. Adverse outcomes as a result of exposure to DLCs have been shown to be mediated through activation of AhR2, but not AhR1, in all fishes studied to date. This indicates that white sturgeon are likely to have greater sensitivity in vivo relative to lake sturgeon. Homology modeling and in silico mutagenesis suggests that differences in sensitivity to activation of AhR2 result from differences in key amino acids at position 388 in the LBD of AhR2 of white sturgeon (Ala-388) and lake sturgeon (Thr-388). This indicates that identities of key amino acids in the LBD of AhR2 could be predictive of both in vitro activation by DLCs and in vivo sensitivity to DLCs in these, and potentially other, fishes.

  9. Open pit blasting in India

    SciTech Connect

    Wasson, D.A.; Garg, D.D.

    1995-12-31

    Open pit blasting in India uses two types of explosives. First there are bulk explosives for wet and dry holes, and there are packaged explosives. The Indian open pit coal mining is projected to use 190 thousand metric tons of explosives in 1995. This volume is projected to grow for the next ten years, whereas the underground coal mining will hold fairly constant. Bulk explosives started in about 1977 with watergels. In the late 1980s, bulk emulsions and heavy ANFOs were introduced. This system is still being expanded and is replacing packaged products in the larger mines. Packaged products are still popular where the annual consumption is less than 2,000 metric tons per year. Also, packaged products are used in small wet shots. Porous ammonium nitrate prill have recently become available but ANFO is not very common because of the high cost of the prill and the wet blasting conditions. As the market expands there will be a continuing demand for packaged products but an increasing demand for bulk waterproof products, particularly in the larger operations. Dynamites are produced at four plants in India. The annual production of about 45,000 metric tons per year is holding fairly constant, but is likely to decrease in the future. The future blasting in India will primarily use pumped emulsions and heavy ANFO on an increasing basis, but the packaged products will maintain their position.

  10. 7 CFR 52.807 - Freedom from pits.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... CERTAIN OTHER PROCESSED FOOD PRODUCTS 1 United States Standards for Grades of Frozen Red Tart Pitted... allowances in this subpart is a whole pit or portions of pits computed as follows: (i) A single piece of pit shell, whether or not within or attached to a whole cherry, that is larger than one-half pit shell...

  11. 7 CFR 52.779 - Freedom from pits.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    .... Canned red tart pitted cherries that are practically free from pits may be given a score of 18 to 20 points. “Practically free from pits” means that the number of pits that may be present in the drained...) classification. Canned red tart pitted cherries that are reasonably free from pits may be given a score of 16...

  12. [Microeukaryotic biodiversity in the waste ore samples surrounding an acid mine drainage lake].

    PubMed

    Li, Si-Yuan; Hao, Chun-Bo; Wang, Li-Hua; Lü, Zheng; Zhang, Li-Na; Liu, Ying; Feng, Chuan-Ping

    2013-10-01

    The abandoned mineral samples were collected in an acid mine drainage area in Anhui Province. Molecular ecological methods were used to construct 18S rDNA clone libraries after analyzing the main physicochemical parameters, and then the microeukaryotic diversity and community structure in the acid mine drainage area were studied. The results showed that the region was strongly acidic (pH <3), and the concentrations of Fe, SO2-(4), P, NO-(3) -N showed the same trend, all higher in the bare waste ore samples PD and 1 M than in the vegetation covered samples LW and XC. Four eukaryotic phyla were detected in the abandoned mineral samples: Ascomycota, Basidiomycota, Glomeromycota and Arthropoda. Glomeromycota can form an absolute symbiotic relationship with the plant, and it was a key factor for early plant to adapt the terrestrial environment. The biodiversity of the vegetation covered samples LW and XC, which contained Glomeromycota, was much higher than that of the bare abandoned rock samples PD and 1 M. Moreover, many sequences in the libraries were closely related to some isolated strains, which are tolerant to low pH and heavy metals, such as Penicillium purpurogenum, Chaetothyriales sp. and Staninwardia suttonii.

  13. Influence of pH on terminal carbon metabolism in anoxic sediments from a mildly acidic lake

    SciTech Connect

    Phelps, T.J.; Zeikus, J.G.

    1984-12-01

    The carbon and electron flow pathways and the bacterial populations responsible for transformation of H/sub 2/-CO/sub 2/, formate, methanol, methylamine, acetate, glycine, ethanol, and lactate were examined in sediments collected from Knaack Lake, Wisconsin. The sediments were 60% organic matter (pH 6.2) and did not display detectable sulfate-reducing activity, but they contained the following average concentration (in micromoles per liter of sediment) of metabolites and end products: sulfide, 10; methane, 1540; CO/sub 2/, 3950; formate, 25; acetate, 157; ethanol, 174; and lactate, 138. Methane was produced predominately from acetate, and only 4% of the total CH/sub 4/ was derived from CO/sub 2/. Methanogenesis was limited by low environmental temperature and sulfide levels and more importantly by low pH. Increasing in vitro pH to neutral values enhanced total methane production rates and the percentage of CO/sub 2/ transformed to methane but did not alter the amount of /sup 14/CO/sub 2/ produced from (2-/sup 14/C)acetate (approx. 24%). Analysis of both carbon transformation parameters with /sup 14/C-labeled tracers and bacterial trophic group enumerations indicated that methanogenesis from acetate and both heterolactic- and acetic acid-producing fermentations were important to the anaerobic digestion process.

  14. Mineralogy of evaporite deposits on Mars: Constraints from laboratory, field, and remote measurements of analog terrestrial acid saline lakes

    NASA Astrophysics Data System (ADS)

    Bridges, N.; Núñez, J. I.; Seelos, F. P., IV; Hook, S. J.; Baldridge, A. M.; Thomson, B. J.

    2015-12-01

    Remote compositional data from imaging spectrometers such as CRISM, OMEGA, and TES, and high-resolution imagery from MOC, CTX, and HiRISE have provided invaluable information for improving our understanding of the composition and geologic history of the martian surface and identifying potential past and present habitable environments on Mars. Simulated CRISM spectra and summary parameter maps and HiRISE color images were generated using airborne hyperspectral data of two acid-saline lakes in Western Australia. These locations are applicable to Mars, as they contain a suite of clays, sulfates, and salts formed under variable pH and salinity - mineralogies similar to those observed in Noachian and Hesperian terrain. The remote datasets were used to make surface composition predictions which were then verified through field study and sample analysis. We find phyllosilicates intermixed with sulfates in sulfate-rich surfaces exhibit variable spectral responses, even for similar conditions and abundances seen in the field. Where sulfates, such as gypsum and alunite, are found, phyllosilicates are intermixed or reside beneath the surface yet are not always detected. This suggests that geologic complexities may mask phyllosilicate detection at or near the surface on Mars where only sulfates have so far been found.

  15. COPPER PITTING AND PINHOLE LEAK RESEARCH STUDY

    EPA Science Inventory

    Localized copper corrosion or pitting is a significant problem at many water utilities across the United States. Copper pinhole leak problems resulting from extensive pitting are widely under reported. Given the sensitive nature of the problem, extent of damage possible, costs o...

  16. Speed, Acceleration, Chameleons and Cherry Pit Projectiles

    ERIC Educational Resources Information Center

    Planinsic, Gorazd; Likar, Andrej

    2012-01-01

    The paper describes the mechanics of cherry pit projectiles and ends with showing the similarity between cherry pit launching and chameleon tongue projecting mechanisms. The whole story is written as an investigation, following steps that resemble those typically taken by scientists and can therefore serve as an illustration of scientific…

  17. Lake Life.

    ERIC Educational Resources Information Center

    Ohrn, Deborah Gore, Ed.

    1993-01-01

    This quarterly publication of the State Historical Society of Iowa features articles and activities for elementary school students. This summer issue focuses on the topic of lake life. The issue includes the following features: (1) "Where the Lakes Are Map"; (2) "Letter from the Lake"; (3) "Lake People"; (4) "Spirit Lake"; (5) "Lake Manawa"; (6)…

  18. The relationship between induction time for pitting and pitting potential for high purity aluminum.

    SciTech Connect

    Wall, Frederick Douglas; Vandenavyle, Justin J.; Martinez, Michael A.

    2003-08-01

    The objective of this study was to determine if a distribution of pit induction times (from potentiostatic experiments) could be used to predict a distribution of pitting potentials (from potentiodynamic experiments) for high-purity aluminum. Pit induction times were measured for 99.99 Al in 50 mM NaCl at potentials of -0.35, -0.3, -0.25, and -0.2 V vs. saturated calomel electrode. Analysis of the data showed that the pit germination rate generally was an exponential function of the applied potential; however, a subset of the germination rate data appeared to be mostly potential insensitive. The germination rate behavior was used as an input into a mathematical relationship that provided a prediction of pitting potential distribution. Good general agreement was found between the predicted distribution and an experimentally determined pitting potential distribution, suggesting that the relationships presented here provide a suitable means for quantitatively describing pit germination rate.

  19. The chemical identity of intervessel pit membranes in Acer challenges hydrogel control of xylem hydraulic conductivity.

    PubMed

    Klepsch, Matthias M; Schmitt, Marco; Paul Knox, J; Jansen, Steven

    2016-01-01

    Ion-mediated enhancement of the hydraulic conductivity of xylem tissue (i.e. the ionic effect) has been reported for various angiosperm species. One explanation of the ionic effect is that it is caused by the swelling and shrinking of intervessel pit membranes due to the presence of pectins and/or other cell-wall matrix polymers such as heteroxylans or arabinogalactan-proteins (AGPs) that may contain acidic sugars. Here, we examined the ionic effect for six Acer species and their pit membrane chemistry using immunocytochemistry, including antibodies against glycoproteins. Moreover, anatomical features related to the bordered pit morphology and vessel dimensions were investigated using light and electron microscopy. The ionic effect varied from 18 % (± 9) to 32 % (± 13). Epitopes of homogalacturonan (LM18) and xylan (LM11) were not detected in intervessel pit membranes. Negative results were also obtained for glycoproteins (extensin: LM1, JIM20; AGP glycan: LM2), although AGP (JIM13)-related epitopes were detected in parenchyma cells. The mean vessel length was significantly correlated with the magnitude of the ionic effect, unlike other pit or vessel-related characteristics. Our results suggest that intervessel pit membranes of Acer are unlikely to contain pectic or other acidic polysaccharides. Therefore, alternative explanations should be tested to clarify the ionic effect.

  20. The chemical identity of intervessel pit membranes in Acer challenges hydrogel control of xylem hydraulic conductivity.

    PubMed

    Klepsch, Matthias M; Schmitt, Marco; Paul Knox, J; Jansen, Steven

    2016-01-01

    Ion-mediated enhancement of the hydraulic conductivity of xylem tissue (i.e. the ionic effect) has been reported for various angiosperm species. One explanation of the ionic effect is that it is caused by the swelling and shrinking of intervessel pit membranes due to the presence of pectins and/or other cell-wall matrix polymers such as heteroxylans or arabinogalactan-proteins (AGPs) that may contain acidic sugars. Here, we examined the ionic effect for six Acer species and their pit membrane chemistry using immunocytochemistry, including antibodies against glycoproteins. Moreover, anatomical features related to the bordered pit morphology and vessel dimensions were investigated using light and electron microscopy. The ionic effect varied from 18 % (± 9) to 32 % (± 13). Epitopes of homogalacturonan (LM18) and xylan (LM11) were not detected in intervessel pit membranes. Negative results were also obtained for glycoproteins (extensin: LM1, JIM20; AGP glycan: LM2), although AGP (JIM13)-related epitopes were detected in parenchyma cells. The mean vessel length was significantly correlated with the magnitude of the ionic effect, unlike other pit or vessel-related characteristics. Our results suggest that intervessel pit membranes of Acer are unlikely to contain pectic or other acidic polysaccharides. Therefore, alternative explanations should be tested to clarify the ionic effect. PMID:27354661

  1. The chemical identity of intervessel pit membranes in Acer challenges hydrogel control of xylem hydraulic conductivity

    PubMed Central

    Klepsch, Matthias M.; Schmitt, Marco; Paul Knox, J.; Jansen, Steven

    2016-01-01

    Ion-mediated enhancement of the hydraulic conductivity of xylem tissue (i.e. the ionic effect) has been reported for various angiosperm species. One explanation of the ionic effect is that it is caused by the swelling and shrinking of intervessel pit membranes due to the presence of pectins and/or other cell-wall matrix polymers such as heteroxylans or arabinogalactan–proteins (AGPs) that may contain acidic sugars. Here, we examined the ionic effect for six Acer species and their pit membrane chemistry using immunocytochemistry, including antibodies against glycoproteins. Moreover, anatomical features related to the bordered pit morphology and vessel dimensions were investigated using light and electron microscopy. The ionic effect varied from 18 % (± 9) to 32 % (± 13). Epitopes of homogalacturonan (LM18) and xylan (LM11) were not detected in intervessel pit membranes. Negative results were also obtained for glycoproteins (extensin: LM1, JIM20; AGP glycan: LM2), although AGP (JIM13)-related epitopes were detected in parenchyma cells. The mean vessel length was significantly correlated with the magnitude of the ionic effect, unlike other pit or vessel-related characteristics. Our results suggest that intervessel pit membranes of Acer are unlikely to contain pectic or other acidic polysaccharides. Therefore, alternative explanations should be tested to clarify the ionic effect. PMID:27354661

  2. Iron buffer system in the water column and partitioning in the sediments of the naturally acidic Lake Caviahue, Neuquén, Argentina

    NASA Astrophysics Data System (ADS)

    Cabrera, J. M.; Diaz, M. M.; Schultz, S.; Temporetti, P.; Pedrozo, F.

    2016-05-01

    Sedimentary iron partitioning was studied for five sediment strata (16 cm depth) at three sampling sites of the naturally-occurring acidic Lake Caviahue (Patagonia, Argentina). Additionally, water column iron was modeled based on five-year period input loadings to study a possible iron buffer system. The partition coefficient between the water column and the total iron content of the sediments was also addressed. Sedimentary iron was found to be distributed, on average, in the following forms: exchangeable (6%), iron oxides (4%), pyrite and reactive organic matter (38%) and residual (non-andesitic) materials with a high content of humic acids (52%). Furthermore, we found that the dissolved iron in the lake was nearly constant throughout the five year period we studied. This is consistent with the existence of an iron buffer system in the lake at pH between 2.0 and 3.0, which may cause differential iron precipitation at the delta of the volcanic river with respect to the deeper northern and southern arms. Sedimentary iron measurements taken at the delta further support the existence of a buffer system, where it was found that the iron content in the sub-superficial stratum (2 cm) was double that of the remainder of the vertical profile at the same site.

  3. Arne - Exploring the Mare Tranquillitatis Pit

    NASA Astrophysics Data System (ADS)

    Robinson, M. S.; Thangavelautham, J.; Wagner, R.; Hernandez, V. A.; Finch, J.

    2014-12-01

    Lunar mare "pits" are key science and exploration targets. The first three pits were discovered within Selene observations [1,2] and were proposed to represent collapses into lava tubes. Subsequent LROC images revealed 5 new mare pits and showed that the Mare Tranquillitatis pit (MTP; 8.335°N, 33.222°E) opens into a sublunarean void at least 20-meters in extent [3,4]. A key remaining task is determining pit subsurface extents, and thus fully understanding their exploration and scientific value. We propose a simple and cost effective reconnaissance of the MTP using a small lander (<130 kg) named Arne, that carries three flying microbots (or pit-bots) [5,6,7]. Key measurement objectives include decimeter scale characterization of the pit walls, 5-cm scale imaging of the eastern floor, determination of the extent of sublunarean void(s), and measurement of the magnetic and thermal environment. After landing and initial surface systems check Arne will transmit full resolution descent and surface images. Within two hours the first pit-bot will launch and fly into the eastern void. Depending on results from the first pit-bot the second and third will launch and perform follow-up observations. The primary mission is expected to last 48-hours; before the Sun sets on the lander there should be enough time to execute ten flights with each pit-bot. The pit-bots are 30-cm diameter spherical flying robots [5,6,7] equipped with stereo cameras, temperature sensors, sensors for obstacle avoidance and a laser rangefinder. Lithium hydride [5,6] and water/hydrogen peroxide power three micro-thrusters and achieve a specific impulse of 350-400 s. Each pit-bot can fly for 2 min at 2 m/s for more than 100 cycles; recharge time is 20 min. Arne will carry a magnetometer, thermometer, 2 high resolution cameras, and 6 wide angle cameras and obstacle avoidance infrared sensors enabling detailed characterization of extant sublunarean voids. [1] Haruyama et al. (2010) 41st LPSC, #1285. [2

  4. Stability of uncoated and fulvic acids coated manufactured CeO2 nanoparticles in various conditions: From ultrapure to natural Lake Geneva waters.

    PubMed

    Oriekhova, Olena; Stoll, Serge

    2016-08-15

    Understanding the behavior of engineered nanoparticles in natural water and impact of water composition in changing conditions is of high importance to predict their fate once released into the environment. In this study we investigated the stability of uncoated and Suwannee River fulvic acids coated CeO2 manufactured nanoparticles in various environmental conditions. The effect of pH changes on the nanoparticle and coating stability was first studied in ultrapure water as well as the variation of zeta potentials and sizes with time in presence of fulvic acids at environmental pH. Then the stability of CeO2 in synthetic and natural Lake Geneva waters was investigated as a function of fulvic acids concentration. Our results indicate that the adsorption of environmentally relevant concentrations of Suwannee River fulvic acids promotes CeO2 stabilization in ultrapure water as well as synthetic water and that the coating stability is high upon pH variations. On the other hand in natural Lake Geneva water CeO2 NPs are found in all cases aggregated due to the effect of heterogeneous organic and inorganic compounds.

  5. Pitted keratolysis, erythromycin, and hyperhidrosis.

    PubMed

    Pranteda, Guglielmo; Carlesimo, Marta; Pranteda, Giulia; Abruzzese, Claudia; Grimaldi, Miriam; De Micco, Sabrina; Muscianese, Marta; Bottoni, Ugo

    2014-01-01

    Pitted keratolysis (PK) is a plantar skin disorder mainly caused by coryneform bacteria. A common treatment consists of the topical use of erythromycin. Hyperhidrosis is considered a predisposing factor for bacterial proliferation and, consequently, for the onset of PK. The aim of this study was to evaluate the relationship between PK erythromycin and hyperhidrosis. All patients with PK seen in Sant'Andrea Hospital, between January 2009 and December 2011, were collected. PK was clinically and microscopically diagnosed. All patients underwent only topical treatment with erythromycin 3% gel twice daily. At the beginning of the study and after 5 and 10 days of treatment, a clinical evaluation and a gravimetric measurement of plantar sweating were assessed. A total of 97 patients were diagnosed as PK and were included in the study. Gravimetric measurements showed that in 94 of 97 examined patients (96.90%) at the time of the diagnosis, there was a bilateral excessive sweating occurring specifically in the areas affected by PK. After 10 days of antibiotic therapy, hyperhidrosis regressed together with the clinical manifestations. According to these data, we hypothesize that hyperhidrosis is due to an eccrine sweat gland hyperfunction, probably secondary to bacterial infection. PMID:24703267

  6. Cherry Pit Primes Brad Pitt

    PubMed Central

    Burke, Deborah M.; Locantore, Jill Kester; Austin, Ayda A.; Chae, Bryan

    2008-01-01

    This study investigated why proper names are difficult to retrieve, especially for older adults. On intermixed trials, young and older adults produced a word for a definition or a proper name for a picture of a famous person. Prior production of a homophone (e.g., pit) as the response on a definition trial increased correct naming and reduced tip-of-the-tongue experiences for a proper name (e.g., Pitt) on a picture-naming trial. Among participants with no awareness of the homophone manipulation, older but not young adults showed these homophone priming effects. With a procedure that reduced awareness effects (Experiment 2), prior production of a homophone improved correct naming only for older adults, but speeded naming latency for both age groups. We suggest that representations of proper names are susceptible to weak connections that cause deficits in the transmission of excitation, impairing retrieval especially in older adults. We conclude that homophone production strengthens phonological connections, increasing the transmission of excitation. PMID:15016287

  7. Pitted keratolysis, erythromycin, and hyperhidrosis.

    PubMed

    Pranteda, Guglielmo; Carlesimo, Marta; Pranteda, Giulia; Abruzzese, Claudia; Grimaldi, Miriam; De Micco, Sabrina; Muscianese, Marta; Bottoni, Ugo

    2014-01-01

    Pitted keratolysis (PK) is a plantar skin disorder mainly caused by coryneform bacteria. A common treatment consists of the topical use of erythromycin. Hyperhidrosis is considered a predisposing factor for bacterial proliferation and, consequently, for the onset of PK. The aim of this study was to evaluate the relationship between PK erythromycin and hyperhidrosis. All patients with PK seen in Sant'Andrea Hospital, between January 2009 and December 2011, were collected. PK was clinically and microscopically diagnosed. All patients underwent only topical treatment with erythromycin 3% gel twice daily. At the beginning of the study and after 5 and 10 days of treatment, a clinical evaluation and a gravimetric measurement of plantar sweating were assessed. A total of 97 patients were diagnosed as PK and were included in the study. Gravimetric measurements showed that in 94 of 97 examined patients (96.90%) at the time of the diagnosis, there was a bilateral excessive sweating occurring specifically in the areas affected by PK. After 10 days of antibiotic therapy, hyperhidrosis regressed together with the clinical manifestations. According to these data, we hypothesize that hyperhidrosis is due to an eccrine sweat gland hyperfunction, probably secondary to bacterial infection.

  8. Characterization of year-round sensitivity of California's Montane Lakes to acidic deposition. Final report, October 1986-June 1989

    SciTech Connect

    Sickman, J.O.; Melack, J.M.

    1989-06-01

    Four high-elevation, lake watersheds in the Sierra Nevada were studied from October 1986 through June 1988. Researchers measured wet deposition, lake outflow and lake chemistry and physics at these sites using the mass-balance approach to relate the effect of wet deposition on lake and stream water chemistry. Crystal and Ruby Lakes, located on the eastern slope of the Sierra, and Topaz and Pear Lakes, located on the western slope in Sequoia National Park, were found to be dimictic. Major solute concentrations in the subsurface reached a minima during the latter part of snowmelt. Near-bottom concentrations of these solutes generally had less seasonal variation and were generally higher than subsurface values. Mean snow depth and chemical concentrations were similar for the winters of 1986-87 and 1987-88 at all watersheds. Volume-weighted mean pH ranged from 5.3 to 5.5, with the dominant ion being hydrogen, ammonium, acetate, nitrate and sulfate. Wet deposition as mixed rain and snow occurring between May and October can deliver more solutes to the watersheds than winter snows.

  9. Lessons Learned from Pit Viper System Deployment

    SciTech Connect

    Catalan, Michael A.; Bailey, Sharon A.; Alzheimer, James M.; Baker, Carl P.; Valdez, Patrick L.

    2002-08-08

    The Pit Viper is a tele-operated system intended to enhance worker safety while simultaneously improving the efficiency of pit operations at the Hanford Site. Commercial off-the-shelf (COTS) components were used in an attempt to increase system reliability and reduce integration difficulties. The Pit Viper, as is, provides significant improvement over the current baseline approach. During integration, multiple areas where technology development would enhance the effectiveness of the system were identified. Most notable of these areas were the manipulator control system, tool design, and tool handling. Various issues were identified regarding the interfacing of the Pit Viper with the Tank Farm environment and the maturity of remote/ robotic systems for unstructured environments.

  10. Okay, Kids, Everyone into the Pit!

    ERIC Educational Resources Information Center

    Belle, Bob; And Others

    1988-01-01

    Discusses a typical food chain and the interrelationship between plants and animals. Describes the "Food Chain Pit" game which can be used to help students create food chains of different habitats. (RT)

  11. Changes in pit membrane porosity due to deflection and stretching: the role of vestured pits.

    PubMed

    Choat, Brendan; Jansen, Steven; Zwieniecki, Maciej A; Smets, Erik; Holbrook, N Michele

    2004-07-01

    The effect of increasing pressure difference (DeltaP) on intervessel pit membrane porosity was studied in two angiosperm tree species with differing pit architecture. Fraxinus americana L. possesses typical angiosperm bordered pit structure while Sophora japonica L. exhibits well-developed vestures in intervessel pit chambers. It was hypothesized (a) that large DeltaP across intervessel pits would cause the deflection of pit membranes in the stems of F. americana resulting in significant increases in porosity and thus lower cavitation thresholds, and (b) that the presence of vestures would prevent the deflection of pit membranes in S. japonica. To determine if the porosity of pit membranes increased under mechanical stress, suspensions of colloidal gold, 5 nm and 20 nm in diameter, were perfused across intervessel pit membranes at DeltaP ranging from 0.25 MPa to 6.0 MPa. The effect of increasing DeltaP on membrane porosity was also tested by comparing air seeding thresholds (Pa) in stems perfused with water or a solution with lower surface tension. Air seeding and colloidal gold experiments indicated that pit membrane porosity increased significantly with DeltaP in F. americana. In S. japonica, increases in permeability to colloidal gold with DeltaP were small and maximum pore diameters predicted from Pa were independent of DeltaP, suggesting that vestures limited the degree to which the membrane can be deflected from the centre of the pit cavity. This provides the first experimental evidence that vestures reduce the probability of air seeding through pit membranes. PMID:15181107

  12. Illuminating Anaerobic Microbial Community and Cooccurrence Patterns across a Quality Gradient in Chinese Liquor Fermentation Pit Muds

    PubMed Central

    Hu, Xiaolong; Du, Hai; Ren, Cong

    2016-01-01

    Fermentation pit mud, an important reservoir of diverse anaerobic microorganisms, is essential for Chinese strong-aroma liquor production. Pit mud quality, according to its sensory characteristics, can be divided into three grades: degraded, normal, and high quality. However, the relationship between pit mud microbial community and pit mud quality is poorly understood, as are microbial associations within the pit mud ecosystem. Here, microbial communities at these grades were compared using Illumina MiSeq sequencing of the variable region V4 of the 16S rRNA gene. Our results revealed that the pit mud microbial community was correlated with its quality and environmental factors. Species richness, biodiversity, and relative and/or absolute abundances of Clostridia, Clostridium kluyveri, Bacteroidia, and Methanobacteria significantly increased, with corresponding increases in levels of pH, NH4+, and available phosphorus, from degraded to high-quality pit muds, while levels of Lactobacillus, dissolved organic carbon, and lactate significantly decreased, with normal samples in between. Furthermore, 271 pairs of significant and robust correlations (cooccurrence and negative) were identified from 76 genera using network analysis. Thirteen hubs of cooccurrence patterns, mainly under the Clostridia, Bacteroidia, Methanobacteria, and Methanomicrobia, may play important roles in pit mud ecosystem stability, which may be destroyed with rapidly increased levels of lactic acid bacteria (Lactobacillus, Pediococcus, and Streptococcus). This study may help clarify the relationships among microbial community, environmental conditions, and pit mud quality, allow the improvement of pit mud quality by using bioaugmentation and controlling environmental factors, and shed more light on the ecological rules guiding community assembly in pit mud. PMID:26896127

  13. Illuminating Anaerobic Microbial Community and Cooccurrence Patterns across a Quality Gradient in Chinese Liquor Fermentation Pit Muds.

    PubMed

    Hu, Xiaolong; Du, Hai; Ren, Cong; Xu, Yan

    2016-04-01

    Fermentation pit mud, an important reservoir of diverse anaerobic microorganisms, is essential for Chinese strong-aroma liquor production. Pit mud quality, according to its sensory characteristics, can be divided into three grades: degraded, normal, and high quality. However, the relationship between pit mud microbial community and pit mud quality is poorly understood, as are microbial associations within the pit mud ecosystem. Here, microbial communities at these grades were compared using Illumina MiSeq sequencing of the variable region V4 of the 16S rRNA gene. Our results revealed that the pit mud microbial community was correlated with its quality and environmental factors. Species richness, biodiversity, and relative and/or absolute abundances of Clostridia,Clostridium kluyveri, Bacteroidia, and Methanobacteria significantly increased, with corresponding increases in levels of pH, NH4 (+), and available phosphorus, from degraded to high-quality pit muds, while levels of Lactobacillus, dissolved organic carbon, and lactate significantly decreased, with normal samples in between. Furthermore, 271 pairs of significant and robust correlations (cooccurrence and negative) were identified from 76 genera using network analysis. Thirteen hubs of cooccurrence patterns, mainly under the Clostridia,Bacteroidia,Methanobacteria, and Methanomicrobia, may play important roles in pit mud ecosystem stability, which may be destroyed with rapidly increased levels of lactic acid bacteria (Lactobacillus,Pediococcus, and Streptococcus). This study may help clarify the relationships among microbial community, environmental conditions, and pit mud quality, allow the improvement of pit mud quality by using bioaugmentation and controlling environmental factors, and shed more light on the ecological rules guiding community assembly in pit mud.

  14. Pit 9 project: A private sector initiative

    SciTech Connect

    Macdonald, D.W.; Hughes, F.P.; Burton, B.N.

    1993-05-01

    This report discusses the Pit 9 Comprehensive Demonstration which is intended to demonstrate a cost-effective approach to remediate an Idaho National Engineering Laboratory (INEL) waste disposal pit through a Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) Interim Action. The remediation will include additional requirements, if needed, to provide high confidence that only minor additional work would be necessary to accomplish the final closure as part of the overall final closure strategy for the INEL`s Subsurface Disposal Area (SDA).

  15. Using pitting and protection potentials to predict pitting behavior: New insights

    SciTech Connect

    Not Available

    1991-10-01

    A literature review was performed to identify test methods that have been used to examine pitting susceptibility of alloys in chloride (Cl{sup {minus}}) containing environments. Several techniques were identified and a critical analysis of the validity of the different electrochemical methods was performed with special attention given to the causes of variations observed in the pitting, or breakdown, potential (E{sub pit}) and the protection, or repassivation, potential (E{sub prot}). Experiments were performed on Type 317L stainless steel in three solutions containing high levels of Cl{sup {minus}} and Alloy G3 in two solutions containing high levels of Cl{sup {minus}}. The test solutions were designed to simulate environments present in flue gas desulfurization systems. Cyclic potentiodynamic polarization (CPP) experiments and constant potential-time experiments (up to 60 days) were performed to examine pit initiation and repassivation; and modified ASTM F-746 tests were performed to establish the protection potential as a function of prior pitting history. Analysis of the data suggests that there exists a unique pitting potential (E{sub u}) defined by the stochastic models for pit initiation that equals the most active value of E{sub pit} (long incubation times) and that equals the most noble E{sub prot} value (measured following only minimal pit growth). 24 refs., 34 figs., 7 tabs.

  16. 7 CFR 987.105 - Whole equivalent of pitted dates.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... Whole equivalent of pitted dates. For the purposes of this part, the whole date equivalent weight of pitted dates shall be determined by dividing the weight of the pitted dates by 0.83. Identification and... 7 Agriculture 8 2012-01-01 2012-01-01 false Whole equivalent of pitted dates. 987.105 Section...

  17. 7 CFR 987.105 - Whole equivalent of pitted dates.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... Whole equivalent of pitted dates. For the purposes of this part, the whole date equivalent weight of pitted dates shall be determined by dividing the weight of the pitted dates by 0.83. Identification and... 7 Agriculture 8 2010-01-01 2010-01-01 false Whole equivalent of pitted dates. 987.105 Section...

  18. 7 CFR 987.105 - Whole equivalent of pitted dates.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... Whole equivalent of pitted dates. For the purposes of this part, the whole date equivalent weight of pitted dates shall be determined by dividing the weight of the pitted dates by 0.83. Identification and... 7 Agriculture 8 2013-01-01 2013-01-01 false Whole equivalent of pitted dates. 987.105 Section...

  19. 7 CFR 987.105 - Whole equivalent of pitted dates.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... Whole equivalent of pitted dates. For the purposes of this part, the whole date equivalent weight of pitted dates shall be determined by dividing the weight of the pitted dates by 0.83. Identification and... 7 Agriculture 8 2014-01-01 2014-01-01 false Whole equivalent of pitted dates. 987.105 Section...

  20. 7 CFR 987.105 - Whole equivalent of pitted dates.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... Whole equivalent of pitted dates. For the purposes of this part, the whole date equivalent weight of pitted dates shall be determined by dividing the weight of the pitted dates by 0.83. Identification and... 7 Agriculture 8 2011-01-01 2011-01-01 false Whole equivalent of pitted dates. 987.105 Section...

  1. Compatibility in the Ustilago maydis-maize interaction requires inhibition of host cysteine proteases by the fungal effector Pit2.

    PubMed

    Mueller, André N; Ziemann, Sebastian; Treitschke, Steffi; Aßmann, Daniela; Doehlemann, Gunther

    2013-02-01

    The basidiomycete Ustilago maydis causes smut disease in maize, with large plant tumors being formed as the most prominent disease symptoms. During all steps of infection, U. maydis depends on a biotrophic interaction, which requires an efficient suppression of plant immunity. In a previous study, we identified the secreted effector protein Pit2, which is essential for maintenance of biotrophy and induction of tumors. Deletion mutants for pit2 successfully penetrate host cells but elicit various defense responses, which stops further fungal proliferation. We now show that Pit2 functions as an inhibitor of a set of apoplastic maize cysteine proteases, whose activity is directly linked with salicylic-acid-associated plant defenses. Consequently, protease inhibition by Pit2 is required for U. maydis virulence. Sequence comparisons with Pit2 orthologs from related smut fungi identified a conserved sequence motif. Mutation of this sequence caused loss of Pit2 function. Consequently, expression of the mutated protein in U. maydis could not restore virulence of the pit2 deletion mutant, indicating that the protease inhibition by Pit2 is essential for fungal virulence. Moreover, synthetic peptides of the conserved sequence motif showed full activity as protease inhibitor, which identifies this domain as a new, minimal protease inhibitor domain in plant-pathogenic fungi.

  2. King's Bowl Pit Crater, Lava Field and Eruptive Fissure, Idaho - A Multipurpose Volcanic Planetary Analog

    NASA Astrophysics Data System (ADS)

    Hughes, S. S.; Garry, B.; Kobs-Nawotniak, S. E.; Sears, D. W. G.; Borg, C.; Elphic, R. C.; Haberle, C. W.; Kobayashi, L.; Lim, D. S. S.; Sears, H.; Skok, J. R.; Heldmann, J. L.

    2014-12-01

    King's Bowl (KB) and its associated eruptive fissure and lava field on the eastern Snake River Plain, is being investigated by the NASA SSERVI FINESSE (Field Investigations to Enable Solar System Science and Exploration) team as a planetary analog to similar pits on the Moon, Mars and Vesta. The 2,220 ± 100 BP basaltic eruption in Craters of the Moon National Monument and Preserve represents early stages of low shield growth, which was aborted when magma supply was cut off. Compared to mature shields, KB is miniscule, with ~0.02 km3 of lava over ~3 km2, yet the ~6 km long series of fissures, cracks and pits are well-preserved for analog studies of volcanic processes. The termination of eruption was likely related to proximity of the 2,270 ± 50 BP eruption of the much larger Wapi lava field (~5.5 km3 over 325 km2 area) on the same rift. Our investigation extends early work by R. Greeley and colleagues, focusing on imagery, compositional variations, ejecta distribution, dGPS profiles and LiDAR scans of features related to: (1) fissure eruptions - spatter ramparts, cones, feeder dikes, extension cracks; (2) lava lake formation - surface morphology, squeeze-ups, slab pahoehoe lava mounds, lava drain-back, flow lobe overlaps; and (3) phreatic steam blasts - explosion pits, ejecta blankets of ash and blocks. Preliminary results indicate multiple fissure eruptions and growth of a basin-filled lava lake up to ~ 10 m thick with outflow sheet lava flows. Remnant mounds of original lake crust reveal an early high lava lake level, which subsided as much as 5 m as the molten interior drained back into the fissure system. Rapid loss of magma supply led to the collapse of fissure walls allowing groundwater influx that triggered multiple steam blasts along at least 500 m. Early blasts occurred while lake magma pressure was still high enough to produce squeeze-ups when penetrated by ejecta blocks. The King's Bowl pit crater exemplifies processes of a small, but highly energetic

  3. Sources of acid and metals from the weathering of the Dinero waste pile, Lake Fork watershed, Leadville, Colorado

    USGS Publications Warehouse

    Diehl, S.F.; Hageman, Phil L.; Smith, Kathleen S.; Herron, J.T.; Desborough, G.A.

    2005-01-01

    Two trenches were dug into the south Dinero mine-waste pile near Leadville, Colorado, to study the weathering of rock fragments and the mineralogic sources of metal contaminants in the surrounding wetland and Lake Fork Watershed. Water seeping from the base of the south Dinero waste-rock pile was pH 2.9, whereas leachate from a composite sample of the rock waste was pH 3.3. The waste pile was mostly devoid of vegetation, open to infiltration of precipitation, and saturated at the base because of placement in the wetland. The south mine-waste pile is composed of poorly sorted material, ranging from boulder-size to fine-grained rock fragments. The trenches showed both matrix-supported and clast-supported zones, with faint horizontal color banding, suggesting zonation of Fe oxides. Secondary minerals such as jarosite and gypsum occurred throughout the depth of the trenches. Infiltration of water and transport of dissolved material through the pile is evidenced by optically continuous secondary mineral deposits that fill or line voids. Iron-sulfate material exhibits microlaminations with shrinkage cracking and preferential dissolution of microlayers that evidence drying and wetting events. In addition to fluids, submicron-sized to very fine-grained particles such as jarosite are transported through channel ways in the pile. Rock fragments are coated with a mixture of clay, jarosite, and manganese oxides. Dissolution of minerals is a primary source of metals. Skeletal remnants of grains, outlined by Fe-oxide minerals, are common. Potassium jarosite is the most abundant jarosite phase, but Pb-and Ag-bearing jarosite are common. Grain-sized clusters of jarosite suggest that entire sulfide grains were replaced by very fine-grained jarosite crystals. The waste piles were removed from the wetland and reclaimed upslope in 2003. This was an opportunity to test methods to identify sources of acid and metals and metal transport processes within a waste pile. A series of

  4. Baseline Risk Assessment for the F-Area Burning/Rubble Pits and Rubble Pit

    SciTech Connect

    Palmer, E.

    1996-03-01

    This document provides an overview of the Savannah River Site (SRS) and a description of the F-Area Burning/Rubble Pits (BRPs) and Rubble Pit (RP) unit. It also describes the objectives and scope of the baseline risk assessment (BRA).

  5. NELL-1 increases pre-osteoblast mineralization using both phosphate transporter Pit1 and Pit2

    SciTech Connect

    Cowan, Catherine M.; Zhang, Xinli; James, Aaron W.; Mari Kim, T.; Sun, Nichole; Wu, Benjamin; Ting, Kang; Soo, Chia

    2012-06-08

    Highlights: Black-Right-Pointing-Pointer NELL-1 accelerates extracellular matrix mineralization in MC3T3-E1 pre-osteoblasts. Black-Right-Pointing-Pointer NELL-1 significantly increases intracellular inorganic phosphate levels. Black-Right-Pointing-Pointer NELL-1 positively regulates osteogenesis but not proliferation in MC3T3-E1 cells. Black-Right-Pointing-Pointer NELL-1 regulates inorganic phosphate transporter activity. -- Abstract: NELL-1 is a potent osteoinductive molecule that enhances bone formation in multiple animal models through currently unidentified pathways. In the present manuscript, we hypothesized that NELL-1 may regulate osteogenic differentiation accompanied by alteration of inorganic phosphate (Pi) entry into the osteoblast via sodium dependent phosphate (NaPi) transporters. To determine this, MC3T3-E1 pre-osteoblasts were cultured in the presence of recombinant human (rh)NELL-1 or rhBMP-2. Analysis was performed for intracellular Pi levels through malachite green staining, Pit-1 and Pit-2 expression, and forced upregulation of Pit-1 and Pit-2. Results showed rhNELL-1 to increase MC3T3-E1 matrix mineralization and Pi influx associated with activation of both Pit-1 and Pit-2 channels, with significantly increased Pit-2 production. In contrast, Pi transport elicited by rhBMP-2 showed to be associated with increased Pit-1 production only. Next, neutralizing antibodies against Pit-1 and Pit-2 completely abrogated the Pi influx effect of rhNELL-1, suggesting rhNELL-1 is dependent on both transporters. These results identify one potential mechanism of action for rhNELL-1 induced osteogenesis and highlight a fundamental difference between NELL-1 and BMP-2 signaling.

  6. Design considerations for ozone and acid-aerosol exposure and health investigations: the Fairview Lake Summer Camp - photochemical smog case study

    SciTech Connect

    Lioy, P.J.; Spektor, D.; Thurston, G.; Citak, K.; Lippmann, M.

    1987-01-01

    The health effects associated with ozone and acidic particulate sulfate exposures to active children have been and are being addressed in field epidemiological studies at summer camps in rural areas of the Northeastern U.S. The rationale and study design for studies, which have been conducted in Pennsylvania and New Jersey, are developed and reviewed. As background, results are summarized for human clinical and epidemiological studies and animal studies. These provided the basis for selection of health outcomes. Measured results from chemical characterization and transport studies are reviewed to define the criteria used for selection of a site affected by high ozone and acid species during photochemical smog episodes. The integration of the study design is discussed in detail by reviewing its application to the 1984 - Fairview Lake Camp Study (July 8 to August 4). The features of the camp study are reviewed, including the study population, pulmonary function procedures and analyses, air pollution monitoring instrumentation, and the site characteristics.

  7. Influence of in ovo mercury exposure, lake acidity, and other factors on common loon egg and chick quality in Wisconsin

    EPA Science Inventory

    We conducted a field study in Wisconsin to characterize in ovo mercury (Hg) exposure in common loons (Gavia immer). Total Hg mass fractions ranged from 0.17 to 1.23 ìg/g wet weight (ww) in eggs collected from nests on lakes representing a wide range of pH (5.0 - 8.1) and ...

  8. Closure of the Brewer Gold Mine by pit backfilling

    SciTech Connect

    Lewis-Russ, A.; Lupo, J.F.; Bronson, J.M.

    1996-12-31

    Brewer Gold Mine, located in north-central South Carolina, is implementing an innovative reclamation plan that includes backfilling the main Brewer open pit with mine waste. The primary goals of the closure are to reduce acid rock drainage and minimize or eliminate long-term operation and maintenance requirements by restoring the site property to approximate pre-mining topography. The plan calls for consolidation of approximately 200 acres of waste into approximately 20 hectares (50 acres). Much of the material to be backfilled into the pit, including spent heap leach material and waste rock, has acid-generating potential. Therefore, the backfill design integrated geochemical properties of the backfill materials with expected post-closure conditions. A prime consideration was the final position of the water table. Since mining at the site started in the early 1800`s, no records exist of the original groundwater levels. Therefore, the design incorporates a large anoxic limestone drain to control the final groundwater level. Additional amendments are to be placed in targeted areas of the backfill to maximize their utilization. A low-permeability cap system that includes a GEOSYNTHETIC clay liner has been designed to limit infiltration into the backfill.

  9. The 2000/60/EC Water Framework Directive and the Flooding of the Brown Coal Meirama Open Pit (NW Spain)

    NASA Astrophysics Data System (ADS)

    Delgado, J.; Juncosa, R.

    2009-04-01

    Coal mining in Galicia (NW Spain) has been an important activity which came to an end in December, 2007. Hence, for different reasons, the two large brown coal mines in Galicia (the As Pontes mine, run by ENDESA GENERACIÓN, and the Meirama mine, owned by Lignitos de Meirama, S.A., LIMEISA), have started closure procedures, both of which are considering the flooding of the mine pits to create two large lakes (~8 km2 in As Pontes and ~2 km2 in Meirama). They will be unique in Galicia, a nearly lake-free territory. An important point to consider as regards the flooding of the lignite mine pits in Galicia is how the process of the creation of a body of artificial water will adapt to the strict legal demands put forth in the Water Framework Directive. This problem has been carefully examined by different authors in other countries and it raises the question of the need to adapt sampling surveys to monitor a number of key parameters -priority substances, physical and chemical parameters, biological indicators, etc.- that cannot be overlooked. Flooding, in both cases consider the preferential entrance into the mine holes of river-diverted surface waters, in detriment of ground waters in order to minimize acidic inputs. Although both mines are located in the same hydraulic demarcation (i.e. administrative units that, in Spain, are in charge of the public administration and the enforcement of natural water-related laws) the problems facing the corresponding mine managers are different. In the case of Meirama, the mine hole covers the upper third part of the Barcés river catchment, which is a major source of water for the Cecebre reservoir. That reservoir constitutes the only supply of drinking water for the city of A Coruña (~250.000 inhabitants) and its surrounding towns. In this contribution we will discuss how mine managers and the administration have addressed the uncertainties derived from the implementation of the Water Framework Directive in the particular case of

  10. Radiocarbon dating of petroleum-impregnated bone from tar pits at Rancho La Brea, California.

    PubMed

    Ho, T Y; Marcus, L F; Berger, R

    1969-05-30

    A liquid-chromatography method has been developed for the separation of amino acids with the same specific activity in radiocarbon from bones impregnated with isotopically dead petroleum compounds found in the La Brea tar pits. This technique permits the application of radiocarbon dating to such bone assemblages.

  11. Energy saving ideas for open pit mining

    SciTech Connect

    Rixen, W.; Benecke, K.J.

    1981-05-01

    The increasing cost of diesel fuel is making truck haulage in open pit mines less economic. Belt conveyor systems have much lower operating costs but are not as flexible in their application and require more detailed pit planning. The possibility of combining the flexibility of trucks with the low cost of conveyors is offered by the application of semi-mobile crushing plants followed by belt conveyors for the main haul out of the pit. In the first part of this article. Dr.-Ing W. Rixen describes some of the semi-mobile plants already in operation, while in the second section. Dr.-Ing K.J. Benecke discusses a theoretical case study involving trucks, crushers, and conveyors. Since a belt conveyor cannot transport rocks of a size often produced when blasting hard strata, a crusher must be installed before the belt conveyor to reduce the material to a transportable size. This also serves as a primary crusher. The crushing plant is positioned centrally in the mine and trucks haul overburden and ore from the individual faces to the crusher without having to climb long gradients. Therefore, truck haul distances and operating costs are significantly reduced. The resulting savings in operating costs greatly exceeds the additional capital costs for the crushing plant. The use of fully mobile crushers directly fed by the face shovel is well established. Whereas the partial elimination of truck haulage by semi-mobile in-pit crushers is a more recent development. This latter method restricts truck haulage to in-pit operation only, saving costly haulage of material up-grade out of the pit to the crusher or overburden dump. It is particularly applicable to operations where blending is required. In such cases, the flexibility and adaptability of trucks to frequently changing faces is essential, while the semi-mobile crusher reduces haul distances to a minimum.

  12. Field temperature measurements at Erta'Ale Lava Lake, Ethiopia

    NASA Astrophysics Data System (ADS)

    Burgi, Pierre-Yves; Caillet, Marc; Haefeli, Steven

    2002-06-01

    The shield volcano Erta'Ale, situated in the Danakil Depression, Ethiopia, is known for its active lava lake. In February 2001, our team visited this lake, located inside an 80-m-deep pit, to perform field temperature measurements. The distribution and variation of temperature inside the lake were obtained on the basis of infrared radiation measurements performed from the rim of the pit and from the lake shores. The crust temperature was also determined from the lake shores with a thermocouple to calibrate the pyrometer. We estimated an emissivity of the basalt of 0.74 from this experiment. Through the application of the Stefan-Boltzmann law, we then obtained an estimate of the total radiative heat flux, constrained by pyrometer measurements of the pit, and visual observations of the lake activity. Taking into account the atmospheric convective heat flux, the convected magma mass flux needed to balance the energy budget was subsequently derived and found to represent between 510 and 580 kg s-1. The surface circulation of this mass flux was also analyzed through motion processing techniques applied to video images of the lake. Electronic supplementary material to this paper can be obtained by using the Springer LINK server located at http://dx.doi.org/10.1007/s00445-002-0224-3.

  13. Arsia Mons Collapse Pits in IR

    NASA Technical Reports Server (NTRS)

    2004-01-01

    [figure removed for brevity, see original site]

    We will be looking at collapse pits for the next two weeks. Collapse pits on Mars are formed in several ways. In volcanic areas, channelized lava flows can form roofs which insulate the flowing lava. These features are termed lava tubes on Earth and are common features in basaltic flows. After the lava has drained, parts of the roof of the tube will collapse under its own weight. These collapse pits will only be as deep as the bottom of the original lava tube. Another type of collapse feature associated with volcanic areas arises when very large eruptions completely evacuate the magma chamber beneath the volcano. The weight of the volcano will cause the entire edifice to subside into the void space below it. Structural features including fractures and graben will form during the subsidence. Many times collapse pits will form within the graben. In addition to volcanic collapse pits, Mars has many collapse pits formed when volatiles (such as subsurface ice) are released from the surface layers. As the volatiles leave, the weight of the surrounding rock causes collapse pits to form.

    These collapse pits are found on the flank of Arsia Mons and are related to lava tube collapse.

    Image information: IR instrument. Latitude -8.8, Longitude 240.4 East (119.6 West). 100 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal

  14. Characterization of ground-water flow between the Canisteo Mine Pit and surrounding aquifers, Mesabi Iron Range, Minnesota

    USGS Publications Warehouse

    Jones, Perry M.

    2002-01-01

    pit for the calibrated steady-state simulation were most sensitive to changes in horizontal hydraulic conductivity, suggesting that this characteristic is the predominant parameter controlling steady-state water-level and flow conditions. A series of 14 steady-state simulations at constant pit water-level altitudes between 1,300 and 1,324 ft was completed with the calibrated model to assess the effect of current and potential future pit water-level altitudes on ground-water inflow to and outflow from the mine pit. Total simulated ground-water inflow to the mine pit at a constant pit water-level altitude of 1,300 ft was 1.40 ft3/s, with a total simulated ground-water outflow of 0.06 ft3/s discharging from the mine pit to local aquifers. Steady-state simulations indicate that total simulated ground-water inflow will decrease from 1.40 to 1.00 ft3/s and total simulated ground-water outflow will increase from 0.06 to 0.91 ft3/s as the pit water-level altitude rises from 1,300 to 1,324 ft. When the pit water-level altitude is 1,324 ft3/s, the lowest pit-rim altitude, the simulated net ground-water inflow is 0.09 ft3/s. At pit water-level altitudes between 1,302 and 1,306 ft, all but a small rate (less than 0.01 ft3/s) of the total simulated ground-water outflow from the pit occurs in the Trout Lake area. At pit water-level altitudes between 1,308 and 1,324 ft, simulated outflow occurs in three outflow locations: the Trout Lake, the Prairie River, and Holman Lake areas.

  15. Examination of pits in Trojan nuclear power plant steam generator tubes: Final report

    SciTech Connect

    Powell, D.E.

    1989-05-01

    This report presents the results from examination of defects, oxides, and corrosion products on three steam generator tubes removed from the Trojan Nuclear Plant of Portland General Electric. In-generator eddy current inspection of the steam generator tubes suggested the probability of pits in one tube, located several inches above the tubesheet, within the height of the sludge pile. A weak indication was reported in the second tube, also within the height of the sludge pile. Copper signals were reported above the tubesheet and first support plate for the third tube which was removed. Destructive examination revealed numerous pits in a band several inches above the tubesheet. The depth of the pits corresponded to those anticipated by field eddy current testing. The pits contained a chromium rich iron and nickel depleted corrosion product with traces of copper and zinc. Intergranular penetrations were present at the base of the pits. Traces of sulfur and chlorine were found within the penetrations. Additionally, nickel sulfide and copper sulfide ribbons were present within the corrosion products of the pits. Sulfate and chloride anions were also observed in concentrations of hundreds of parts per million (each) within the exterior surface oxides. Hence, the pitting corrosion was attributed to acid forms of sulfur, acting synergistically with chlorides. The oxides on the external surfaces of the steam generator tubes were found to consist of magnetite (Fe/sub 3/O/sub 4/) with minor components of franklinite (ZnFe/sub 2/O/sub 4/). Embedded within this composite were numerous particles of copper in the elemental form. 8 refs.

  16. Analytical data for waters of the Harvard Open Pit, Jamestown Mine, Tuolumne County, California, March 1998-September 1999

    USGS Publications Warehouse

    Ashley, R.P.; Savage, K.S.

    2001-01-01

    The Jamestown mine is located in the Jamestown mining district in western Tuolumne County, California (see Fig. 1). This district is one of many located on or near the Melones fault zone, a major regional suture in the Sierra Nevada foothills. The districts along the Melones fault comprise the Mother Lode gold belt (Clark, 1970). The Harvard pit is the largest of several open pits mined at the Jamestown site by Sonora Mining Corporation between 1986 and 1994 (Fig. 2; Algood, 1990). It is at the site of an historical mine named the Harvard that produced about 100,000 troy ounces of gold, mainly between 1906 and 1916 (Julihn and Horton, 1940). Sonora Mining mined and processed about 17,000,000 short tons of ore, with an overall stripping ratio of about 4.5:1, yielding about 660,000 troy ounces of gold (Nelson and Leicht, 1994). Most of this material came from the Harvard pit, which attained dimensions of about 2700 ft (830 m) in length, 1500 ft (460 m) in width, and 600 ft (185 m) in depth. The bottom of the pit is at an elevation of 870 ft (265 m). Since mining operations ceased in mid-1994, the open pit has been filling with water. As of November, 2000, lake level had reached an elevation of about 1170 ft (357 m). Water quality monitoring data gathered after mine closure showed rising levels of arsenic, sulfate, and other components in the lake, with particularly notable increases accompanying a period of rapid filling in 1995 (County of Tuolumne, 1998). The largest potential source for arsenic in the vicinity of the Harvard pit is arsenian pyrite, the most abundant sulfide mineral related to gold mineralization. A previous study of weathering of arsenian pyrite in similarly mineralized rocks at the Clio mine, in the nearby Jacksonville mining district, showed that arsenic released by weathering of arsenian pyrite is effectively attenuated by adsorption on goethite or coprecipitation with jarosite, depending upon the buffering capacity of the pyrite-bearing rock

  17. COPPER PITTING CORROSION: A CASE STUDY

    EPA Science Inventory

    Localized or pitting corrosion of copper pipes used in household drinking-water plumbing is a problem for many water utilities and their customers. Extreme attack can lead to pinhole water leaks that may result in water damage, mold growth, and costly repairs. Water quality has b...

  18. Extracting Valuable Data from Classroom Trading Pits

    ERIC Educational Resources Information Center

    Bergstrom, Theodore C.; Kwok, Eugene

    2005-01-01

    How well does competitive theory explain the outcome in experimental markets? The authors examined the results of a large number of classroom trading experiments that used a pit-trading design found in Experiments with Economic Principles, an introductory economics textbook by Bergstrom and Miller. They compared experimental outcomes with…

  19. Global methane emissions from pit latrines.

    PubMed

    Reid, Matthew C; Guan, Kaiyu; Wagner, Fabian; Mauzerall, Denise L

    2014-01-01

    Pit latrines are an important form of decentralized wastewater management, providing hygienic and low-cost sanitation for approximately one-quarter of the global population. Latrines are also major sources of the greenhouse gas methane (CH4) from the anaerobic decomposition of organic matter in pits. In this study, we develop a spatially explicit approach to account for local hydrological control over the anaerobic condition of latrines and use this analysis to derive a set of country-specific emissions factors and to estimate global pit latrine CH4 emissions. Between 2000 and 2015 we project global emissions to fall from 5.2 to 3.8 Tg y(-1), or from ∼ 2% to ∼ 1% of global anthropogenic CH4 emissions, due largely to urbanization in China. Two and a half billion people still lack improved sanitation services, however, and progress toward universal access to improved sanitation will likely drive future growth in pit latrine emissions. We discuss modeling results in the context of sustainable water, sanitation, and hygiene development and consider appropriate technologies to ensure hygienic sanitation while limiting CH4 emissions. We show that low-CH4 on-site alternatives like composting toilets may be price competitive with other CH4 mitigation measures in organic waste sectors, with marginal abatement costs ranging from 57 to 944 $/ton carbon dioxide equivalents (CO2e) in Africa and 46 to 97 $/ton CO2e in Asia.

  20. OVERVIEW, LOOKING SOUTHWEST, TO 8750 PIT WITH DRILL SETTING AN ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    OVERVIEW, LOOKING SOUTHWEST, TO 8750 PIT WITH DRILL SETTING AN EXPLOSIVE CHARGE TO REMOVE OVERBURDEN AND ACCESS COAL SEAMS LOCATED 200 FEET BELOW FOR STRIPPING. - Drummond Coal Company Cedrum Mine, 8750 Pit, County Road 124, Townley, Walker County, AL

  1. LONGITUDINAL VIEW OF THE SOAKING PIT BUILDING INTERIOR WITH OPEN ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    LONGITUDINAL VIEW OF THE SOAKING PIT BUILDING INTERIOR WITH OPEN HEARTH IN BACKGROUND AND FURNACE PIT/ STACK AREA TO THE LEFT. - Pittsburgh Steel Company, Monessen Works, Open Hearth Plant, Donner Avenue, Monessen, Westmoreland County, PA

  2. Looking west inside of the soaking pit building for the ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Looking west inside of the soaking pit building for the 44" slab mill at a red hot ingot being removed from a pit. - U.S. Steel Edgar Thomson Works, 44" Slab Mill, Along Monongahela River, Braddock, Allegheny County, PA

  3. GENERAL OVERVIEW, LOOKING EAST, FROM RECLAIMED PASTURE TO 8750 PIT ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    GENERAL OVERVIEW, LOOKING EAST, FROM RECLAIMED PASTURE TO 8750 PIT WITH STRIPPING AND RECLAMATION ACTIVITY ONGOING SIDE BY SIDE. - Drummond Coal Company Cedrum Mine, 8750 Pit, County Road 124, Townley, Walker County, AL

  4. Pit Viper strikes at the Hanford site. Pit maintenance using robotics at the Hanford Tank Farms

    SciTech Connect

    Roeder-Smith, Lynne

    2002-06-30

    The Pit Viper - a remote operations waste retrieval system - was developed to replace manual operations in the valve pits of waste storge tanks at the Hanford Site. The system consists of a typical industrial backhoe fitted with a robotic manipulator arm and is operated remotely from a control trailer located outside of the tank farm. Cameras mounted to the arm and within the containment tent allow the operator to view the entire pit area and operate the system using a joystick. The arm's gripper can grasp a variety of tools that allow personnel to perform cleaning, debris removal, and concrete repair tasks -- a more efficient and less dose-intensive process than the previous "long-pole" method. The project team overcame a variety of obstacles during development and testing of the Pit Viper system, and deployment occurred in Hanford Tank C-104 in December 2001.

  5. Mosh pits and Circle pits: Collective motion at heavy metal concerts

    NASA Astrophysics Data System (ADS)

    Bierbaum, Matthew; Silverberg, Jesse L.; Sethna, James P.; Cohen, Itai

    2013-03-01

    Heavy metal concerts present an extreme environment in which large crowds (~102 -105) of humans experience very loud music (~ 130 dB) in sync with bright, flashing lights, often while intoxicated. In this setting, we find two types of collective motion: mosh pits, in which participants collide with each other randomly in a manner resembling an ideal gas, and circle pits, in which participants run collectively in a circle forming a vortex of people. We model these two collective behaviors using a flocking model and find qualitative and quantitative agreement with the behaviors found in videos of metal concerts. Futhermore, we find a phase diagram showing the transition from a mosh pit to a circle pit as well as a predicted third phase, lane formation.

  6. Effects of salinity and ultraviolet radiation on the bioaccumulation of mycosporine-like amino acids in Artemia from Lake Urmia (Iran).

    PubMed

    Khosravi, Sanaz; Khodabandeh, Saber; Agh, Naser; Bakhtiarian, Mahdieh

    2013-01-01

    We investigated the effects of salinity and artificial UV radiation on the accumulation of mycosporine-like amino acids (MAAs) in sexual and parthenogenetic Artemia from Lake Urmia. The nauplii hatched from the cysts were cultured until adulthood under two salinities (150 and 250 g L(-1) ) and two light treatments (PAR and PAR+UVR) in the laboratory. Finally, the Artemia were analyzed for their concentration of MAAs. In most of the cases, the higher salinity level applied was found to increase the MAA concentrations in both Artemia populations significantly. The acquisition efficiency of MAAs in both Artemia populations increased under exposure to UVR-supplemented photosynthetically active radiation (PAR) compared to those raised under PAR, except for Porphyra-334. It was observed that combination of UV radiation and elevated salinity significantly increased the bioaccumulation of MAAs. Thus, the presence of these compounds in these populations of Artemia may increase their adaptability for living in high-UV and high-salinity conditions prevailing in Lake Urmia. Higher concentrations of MAAs in the parthenogenetic population of Artemia could be probably attributed to its mono sex nature and higher adaptation capacities to extreme environmental conditions. PMID:22998644

  7. 99. ARAIII. Overall view of drilling area in reactor pit. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    99. ARA-III. Overall view of drilling area in reactor pit. Bridge over pit in use for operations. Shows water in pool, reactor, hoist, operators, and general view of interior of reactor pit area. August 12, 1963. Ineel photo no. 63-4454. Photographer: Benson. - Idaho National Engineering Laboratory, Army Reactors Experimental Area, Scoville, Butte County, ID

  8. 10. Turbine Pit of Unit 5, view to the north. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    10. Turbine Pit of Unit 5, view to the north. Note the difference in configuration within this turbine pit as compared to one of the original pits illustrated in photograph number MT-105-A-11. - Washington Water Power Clark Fork River Noxon Rapids Hydroelectric Development, Powerhouse, South bank of Clark Fork River at Noxon Rapids, Noxon, Sanders County, MT

  9. 7 CFR 52.807 - Freedom from pits.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... substantially free from any adhering sirup, sugar, or other packing medium. (c) (A) Classification. Frozen red tart pitted cherries that are practically free from pits may be given a score of 18 to 20 points. “Practically free from pits” means that the number of pits that may be present does not exceed the...

  10. 30 CFR 56.3131 - Pit or quarry wall perimeter.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Pit or quarry wall perimeter. 56.3131 Section... Mining Methods § 56.3131 Pit or quarry wall perimeter. In places where persons work or travel in... stripped back for at least 10 feet from the top of the pit or quarry wall. Other conditions at or near...

  11. Metastable pitting of carbon steel under potentiostatic control

    SciTech Connect

    Cheng, Y.F.; Luo, J.L.

    1999-03-01

    The metastable pitting of A516-70 carbon steel was studied under potentiostatic control in solutions containing chloride ions. It was shown that there were different current fluctuation patterns and spectral slopes, that is, roll-off slopes, in passivity, general corrosion, and metastable pitting. Pits were often covered by a deposit which played an important role in the current fluctuation, with a quick current rise followed by a slow drop. There was a transitional potential (about 0 mV vs Ag/AgCl electrode) below which the metastable pitting initiation rate increased with the potential, because more sites would be activated. Above the transitional potential, the decay of the pitting occurrence rate with increased potential was due to the elimination of available pit sites. When the applied potential was between {minus}50 and 100 mV, pit growth kinetics was controlled by the potential drop through the deposit over the pit mouth. The potential dependence of repassivation time was mainly due to the effect of applied potential on the deposit over the pit mouth. There seemed to be good agreement between the calculated pit size and the measured values by optical microphotography. The assumption of hemispherical pit geometry was reasonable in calculating the pit radii.

  12. Lake Eyre

    Atmospheric Science Data Center

    2013-04-16

    ...   View Larger Image Lake Eyre is a large salt lake situated between two deserts in one of Australia's driest regions. ... the effect of sunglint at the nadir camera view angle. Dry, salt encrusted parts of the lake appear bright white or gray. Purple areas have ...

  13. Analytical data for waters of the Harvard Open Pit, Jamestown Mine, Tuolumne County, California, March 1998-September 1999

    USGS Publications Warehouse

    Ashley, R.P.; Savage, K.S.

    2001-01-01

    The Jamestown mine is located in the Jamestown mining district in western Tuolumne County, California (see Fig. 1). This district is one of many located on or near the Melones fault zone, a major regional suture in the Sierra Nevada foothills. The districts along the Melones fault comprise the Mother Lode gold belt (Clark, 1970). The Harvard pit is the largest of several open pits mined at the Jamestown site by Sonora Mining Corporation between 1986 and 1994 (Fig. 2; Algood, 1990). It is at the site of an historical mine named the Harvard that produced about 100,000 troy ounces of gold, mainly between 1906 and 1916 (Julihn and Horton, 1940). Sonora Mining mined and processed about 17,000,000 short tons of ore, with an overall stripping ratio of about 4.5:1, yielding about 660,000 troy ounces of gold (Nelson and Leicht, 1994). Most of this material came from the Harvard pit, which attained dimensions of about 2700 ft (830 m) in length, 1500 ft (460 m) in width, and 600 ft (185 m) in depth. The bottom of the pit is at an elevation of 870 ft (265 m). Since mining operations ceased in mid-1994, the open pit has been filling with water. As of November, 2000, lake level had reached an elevation of about 1170 ft (357 m). Water quality monitoring data gathered after mine closure showed rising levels of arsenic, sulfate, and other components in the lake, with particularly notable increases accompanying a period of rapid filling in 1995 (County of Tuolumne, 1998). The largest potential source for arsenic in the vicinity of the Harvard pit is arsenian pyrite, the most abundant sulfide mineral related to gold mineralization. A previous study of weathering of arsenian pyrite in similarly mineralized rocks at the Clio mine, in the nearby Jacksonville mining district, showed that arsenic released by weathering of arsenian pyrite is effectively attenuated by adsorption on goethite or coprecipitation with jarosite, depending upon the buffering capacity of the pyrite-bearing rock

  14. Corrosion pitting of SiC by molten salts

    NASA Technical Reports Server (NTRS)

    Jacobson, N. S.; Smialek, J. L.

    1986-01-01

    The corrosion of SiC by thin films of Na2CO3 and Na2SO4 at 1000 C is characterized by a severe pitting attack of the SiC substrate. A range of different Si and SiC substrates were examined to isolate the factors critical to pitting. Two types of pitting attack are identified: attack at structural discontinuities and a crater-like attack. The crater-like pits are correlated with bubble formation during oxidation of the SiC. It appears that bubbles create unprotected regions, which are susceptible to enhanced attack and, hence, pit formation.

  15. Hydrogeological features conditioning trophic levels of quarry lakes in western Po plain (north-western Italy)

    NASA Astrophysics Data System (ADS)

    De Luca, Domenico Antonio; Castagna, Sara; Lasagna, Manuela

    2013-04-01

    Quarry lakes occur in plains areas due to the extraction of alluvial sand and gravel used for grout and concrete in the construction industry. Excavation depths can reach and intersect the groundwater surface, thus creating a lake. Because of the need to optimize efficiency, the number of active open pit mines has increased in recent years; consequently, the global number of pit lakes will increase in coming decades (Castendyk and Eary 2009; Klapper and Geller 2001; Castro and Moore 2000). Similar to natural lakes, pit lakes are subject to eutrophication process, both during and after quarrying activity; during mining activity, the eutrophic level is strongly controlled by the excavation method. In the Piedmont territory (north-western Italy) there are 70 active quarry lakes, corresponding to approximately 0.1% of the entire plain area. Quarry lakes, located primarily along the main rivers occur in alluvial deposits of the plain area and have average depths between 20 and 30 m (maximum of 60 m deep) and surface areas between 3 and 30 hectares (Castagna 2008). The present study describes the trophic status of 23 active quarry lakes in the Piedmont plain that were evaluated by applying classifications from scientific literature. Currently, the majority of the studied quarry lakes may be defined as mesotrophic or eutrophic according to the trophic state classifications. Based on historic data, lake trophic levels have increased over time, during active mining. At the end of mining activity, further deterioration of water quality was expected, especially for smaller lakes with minimal oxygen stratification and higher levels of nutrients and algal growth. In addition, the paper focuses on the pit lake water quality and pit dimension; From an environmental perspective the excavation of quarry lakes with an appreciable size will likely result in a better safeguard of water quality and enhanced possibilities for lake end use after the cessation of mining. Piedmont quarry

  16. Treatment of a mud pit by bioremediation.

    PubMed

    Avdalović, Jelena; Đurić, Aleksandra; Miletić, Srdjan; Ilić, Mila; Milić, Jelena; Vrvić, Miroslav M

    2016-08-01

    The mud generated from oil and natural gas drilling, presents a considerable ecological problem. There are still insufficient remedies for the removal and minimization of these very stable emulsions. Existing technologies that are in use, more or less successfully, treat about 20% of generated waste drilling mud, while the rest is temporarily deposited in so-called mud pits. This study investigated in situ bioremediation of a mud pit. The bioremediation technology used in this case was based on the use of naturally occurring microorganisms, isolated from the contaminated site, which were capable of using the contaminating substances as nutrients. The bioremediation was stimulated through repeated inoculation with a zymogenous microbial consortium, along with mixing, watering and biostimulation. Application of these bioremediation techniques reduced the concentration of total petroleum hydrocarbons from 32.2 to 1.5 g kg(-1) (95% degradation) during six months of treatment. PMID:27354013

  17. Pitting corrosion resistant austenite stainless steel

    DOEpatents

    van Rooyen, D.; Bandy, R.

    A pitting corrosion resistant austenite stainless steel comprises 17 to 28 wt. % chromium, 15 to 26 wt. % nickel, 5 to 8 wt. % molybdenum, and 0.3 to 0.5 wt. % nitrogen, the balance being iron, unavoidable impurities, minor additions made in the normal course of melting and casting alloys of this type, and may optionally include up to 10 wt. % of manganese, up to 5 wt. % of silicon, and up to 0.08 wt. % of carbon.

  18. Pits, pipes, ponds--and me.

    PubMed

    Mara, Duncan

    2013-05-01

    My life in low-cost sanitation and low-cost wastewater treatment and the use of treated wastewater in agriculture and aquaculture really has been 'pits, pipes and ponds' - 'pits' are low-cost sanitation technologies (LCST) such as VIP latrines and pour-flush toilets; 'pipes' are low-cost sewerage, principally condominial (simplified) sewerage; and 'ponds' are low-cost wastewater treatment systems, especially waste stabilization ponds, and the use of treated wastewater in agriculture and aquaculture. 'Pits' were mainly working on World Bank LCST research projects, with fieldwork principally in Zimbabwe, 'pipes' were working on condominial sewerage projects in Brazil and disseminating this LCST to a wider global audience, and 'ponds' were waste stabilization ponds, with fieldwork mainly in Brazil, Colombia, Portugal and the United Kingdom, the development of aerated rock filters to polish facultative-pond effluents, and the human-health aspects of treated wastewater use in agriculture and aquaculture, with fieldwork in Brazil and the UK, and the application of quantitative microbial risk analysis. The paper provides a professional perspective and lessons from historical developments and gives recommended future directions based on my career working on low-cost sanitation technologies and treated wastewater use in agriculture and aquaculture.

  19. Pits, pipes, ponds--and me.

    PubMed

    Mara, Duncan

    2013-05-01

    My life in low-cost sanitation and low-cost wastewater treatment and the use of treated wastewater in agriculture and aquaculture really has been 'pits, pipes and ponds' - 'pits' are low-cost sanitation technologies (LCST) such as VIP latrines and pour-flush toilets; 'pipes' are low-cost sewerage, principally condominial (simplified) sewerage; and 'ponds' are low-cost wastewater treatment systems, especially waste stabilization ponds, and the use of treated wastewater in agriculture and aquaculture. 'Pits' were mainly working on World Bank LCST research projects, with fieldwork principally in Zimbabwe, 'pipes' were working on condominial sewerage projects in Brazil and disseminating this LCST to a wider global audience, and 'ponds' were waste stabilization ponds, with fieldwork mainly in Brazil, Colombia, Portugal and the United Kingdom, the development of aerated rock filters to polish facultative-pond effluents, and the human-health aspects of treated wastewater use in agriculture and aquaculture, with fieldwork in Brazil and the UK, and the application of quantitative microbial risk analysis. The paper provides a professional perspective and lessons from historical developments and gives recommended future directions based on my career working on low-cost sanitation technologies and treated wastewater use in agriculture and aquaculture. PMID:23490108

  20. Constituent Particle Clustering and Pitting Corrosion

    NASA Astrophysics Data System (ADS)

    Harlow, D. Gary

    2012-08-01

    Corrosion is a primary degradation mechanism that affects the durability and integrity of structures made of aluminum alloys, and it is a concern for commercial transport and military aircraft. In aluminum alloys, corrosion results from local galvanic coupling between constituent particles and the metal matrix. Due to variability in particle sizes, spatial location, and chemical composition, to name a few critical variables, corrosion is a complex stochastic process. Severe pitting is caused by particle clusters that are located near the material surface, which, in turn, serve as nucleation sites for subsequent corrosion fatigue crack growth. These evolution processes are highly dependent on the spatial statistics of particles. The localized corrosion growth rate is primarily dependent on the galvanic process perpetuated by particle-to-particle interactions and electrochemical potentials. Frequently, severe pits are millimeters in length, and these pits have a dominant impact on the structural prognosis. To accommodate large sizes, a model for three-dimensional (3-D) constituent particle microstructure is proposed. To describe the constituent particle microstructure in three dimensions, the model employs a fusion of classic stereological techniques, spatial point pattern analyses, and qualitative observations. The methodology can be carried out using standard optical microscopy and image analysis techniques.

  1. Multilayer deformation planarization by substrate pit suturing.

    PubMed

    Chai, Yingjie; Zhu, Meiping; Xing, Huanbin; Wang, Hu; Cui, Yun; Shao, Jianda

    2016-08-01

    In the pursuit of 1064 nm high-power laser resistance dielectric coatings in the nanosecond region, a group of HfO2/SiO2 high reflectors with and without suture layers were prepared on prearranged fused silica substrates with femtosecond laser pits. Surface morphology, global coating stress, and high-resolution cross sections were characterized to determine the effects of substrate pit suturing. Laser-induced damage resistance was investigated for samples with and without suture layers. Our results indicate considerable stability in terms of the nanosecond 1064 nm laser-induced damage threshold for samples having a suture layer, due to decreased electronic field (e-field) deformation with simultaneous elimination of internal cracks. In addition, a suture layer formed by plasma ion-assisted deposition could effectively improve global mechanical stress of the coatings. By effectively reducing the multilayer deformation using a suture layer, electron-beam high-reflective coatings, whose laser-induced damage resistance was not influenced by the substrate pit, can be prepared. PMID:27472579

  2. Using linoleic acid embedded cellulose acetate membranes to in situ monitor polycyclic aromatic hydrocarbons in lakes and predict their bioavailability to submerged macrophytes.

    PubMed

    Tao, Yuqiang; Xue, Bin; Yao, Shuchun

    2015-05-19

    To date no passive sampler has been used to predict bioavailability of contaminants to macrophytes. Here a novel passive sampler, linoleic acid embedded cellulose acetate membrane (LAECAM), was developed and used to in situ measure the freely dissolved concentrations of ten polycyclic aromatic hydrocarbons in the sediment porewaters and the water columns of two lakes in both winter and summer and predict their bioavailability to the shoots of resident submerged macrophytes (Potamogeton malainus, Myriophyllum spicata, Najas minor All., and Vallisneria natans (Lour.) Hara). PAH sampling by LAECAMs could reach equilibrium within 21 days. The influence of temperature on LAECAM-water partition coefficients was 0.0008-0.0116 log units/°C. The method of LAECAM was comparable with the active sampling methods of liquid-liquid extraction combined with fDOC adjustment, centrifugation/solid-phase extraction (SPE), and filtration/SPE but had several advantages. After lipid normalization, concentrations of the PAHs in LAECAMs were not significantly different from those in the macrophytes. In contrast, concentrations of the PAHs in the triolein containing passive sampler (TECAM) deployed simultaneously with LAECAM were much higher. The results suggest that linoleic acid is more suitable than triolein as the model lipid for passive samplers to predict bioavailability of PAHs to submerged macrophytes.

  3. Systematics and species-specific response to pH of Oxytricha acidotolerans sp. nov. and Urosomoida sp. (Ciliophora, Hypotricha) from acid mining lakes

    PubMed Central

    Weisse, Thomas; Moser, Michael; Scheffel, Ulrike; Stadler, Peter; Berendonk, Thomas; Weithoff, Guntram; Berger, Helmut

    2013-01-01

    We investigated the morphology, phylogeny of the 18S rDNA, and pH response of Oxytricha acidotolerans sp. nov. and Urosomoida sp. (Ciliophora, Hypotricha) isolated from two chemically similar acid mining lakes (pH ∼ 2.6) located at Langau, Austria, and in Lusatia, Germany. Oxytricha acidotolerans sp. nov. from Langau has 18 frontal-ventral-transverse cirri but a very indistinct kinety 3 fragmentation so that the assignment to Oxytricha is uncertain. The somewhat smaller species from Lusatia has a highly variable cirral pattern and the dorsal kineties arranged in the Urosomoida pattern and is, therefore, preliminary designated as Urosomoida sp. The pH response was measured as ciliate growth rates in laboratory experiments at pH ranging from 2.5 to 7.0. Our hypothesis was that the shape of the pH reaction norm would not differ between these closely related (3% difference in their SSU rDNA) species. Results revealed a broad pH niche for O. acidotolerans, with growth rates peaking at moderately acidic conditions (pH 5.2). Cyst formation was positively and linearly related to pH. Urosomoida sp. was more sensitive to pH and did not survive at circumneutral pH. Accordingly, we reject our hypothesis that similar habitats would harbour ciliate species with virtually identical pH reaction norm. PMID:23021638

  4. Prokaryotic Communities in Pit Mud from Different-Aged Cellars Used for the Production of Chinese Strong-Flavored Liquor

    PubMed Central

    Tao, Yong; Li, Jiabao; Rui, Junpeng; Xu, Zhancheng; Zhou, Yan; Hu, Xiaohong; Wang, Xiang; Liu, Menghua; Li, Daping

    2014-01-01

    Chinese strong-flavored liquor (CSFL) accounts for more than 70% of all Chinese liquor production. Microbes in pit mud play key roles in the fermentation cellar for the CSFL production. However, microbial diversity, community structure, and cellar-age-related changes in pit mud are poorly understood. Here, we investigated the prokaryotic community structure and diversity in pit-mud samples with different cellar ages (1, 10, 25, and 50 years) using the pyrosequencing technique. Results indicated that prokaryotic diversity increased with cellar age until the age reached 25 years and that prokaryotic community structure changed significantly between three cellar ages (1, 10, and 25 years). Significant correlations between prokaryotic communities and environmental variables (pH, NH4+, lactic acid, butyric acid, and caproic acid) were observed. Overall, our study results suggested that the long-term brewing operation shapes unique prokaryotic community structure and diversity as well as pit-mud chemistry. We have proposed a three-phase model to characterize the changes of pit-mud prokaryotic communities. (i) Phase I is an initial domestication period. Pit mud is characterized by abundant Lactobacillus and high lactic acid and low pH levels. (ii) Phase II is a transition period. While Lactobacillus abundance decreases dramatically, that of Bacteroidetes and methanogens increases. (iii) Phase III is a relative mature period. The prokaryotic community shows the highest diversity and capability to produce more caproic acid as a precursor for synthesis of ethyl caproate, the main flavor component in CSFL. This research provides scientific evidence to support the practical experience that old fermentation cellars produce high-quality liquor. PMID:24487528

  5. Assessing potential for recovery of biotic richness and indicator species due to changes in acidic deposition and lake pH in five areas of southeastern Canada.

    PubMed

    Doka, Susan E; McNicol, Donald K; Mallory, Mark L; Wong, Isaac; Minns, Charles K; Yan, Norman D

    2003-01-01

    Biological damage to sensitive aquatic ecosystems is among the most recognisable, deleterious effects of acidic deposition. We compiled a large spatial database of over 2000 waterbodies across southeastern Canada from various federal, provincial and academic sources. Data for zooplankton, fish, macroinvertebrate (benthos) and loon species richness and occurrence were used to construct statistical models for lakes with varying pH, dissolved organic carbon content and lake size. pH changes, as described and predicted using the Integrated Assessment Model (Lam et al., 1998; Jeffries et al., 2000), were based on the range of emission reductions set forth in the Canada/US Air Quality Agreement (AQA). The scenarios tested include 1983, 1990, 1994 and 2010 sulphate deposition levels. Biotic models were developed for five regions in southeastern Canada (Algoma, Muskoka, and Sudbury, Ontario, southcentral Quebec, and Kejimkujik, Nova Scotia) using regression tree, multiple linear regression and logistic regression analyses to make predictions about recovery after emission reductions. The analyses produced different indicator species in different regions, although some species showed consistent trends across regions. Generally, the greatest predicted recovery occurred during the final phase of emission reductions between 1994 and 2010 across all taxonomic groups and regions. The Ontario regions, on average, were predicted to recover to a greater extent than either southcentral Quebec or the Kejimkujik area of Nova Scotia. Our results reconfirm that pH 5.5-6.0 is an important threshold below which damage to aquatic biota will remain a major local and regional environmental problem. This damage to biodiversity across trophic levels will persist well into the future if no further reductions in sulphate deposition are implemented.

  6. Vertical distributions of bound saturated fatty acids and compound-specific stable carbon isotope compositions in sediments of two lakes in China: implication for the influence of eutrophication.

    PubMed

    Wang, Lifang; Xiong, Yongqiang; Wu, Fengchang; Li, Qiuhua; Lin, Tian; Giesy, John P

    2014-11-01

    Lakes Dianchi (DC) and Bosten (BST) were determined to be at different stages of eutrophication, by use of total organic carbon content, bulk carbon isotopic composition, bulk nitrogen isotopic composition, and bound saturated fatty acid (BSFA) concentrations in sediment cores. A rapid increase in the supply of organic matter (OM) to DC began after the 1950s, while the environment and trophic status of BST remained constant as indicated by characteristics of OM input to sediments. The BSFA ratios of nC14 + nC16 + nC18/nC24 + nC26 + nC28 increase upward from 7 to 13 in the DC core, which are significantly greater than those from BST (2 to 3). This result is consistent with algae or bacteria being the dominant contribution of the OM increase induced by eutrophication in DC. The positive shift of nC16 compound-specific δ (13)C in the upper section might be an indicator of excess algal productivity, which was observed in the two lakes. The positive shifts of compound-specific δ (13)C of other BSFAs were also observed in the upper section of the core only from DC. The observed trends of compound-specific δ(13)C of BSFA originated from different sources became more consistent, which reflected the intensified eutrophication had profoundly affected production and preservation of OM in DC. The results observed for BST indicated that accumulation of algae did not affect the entire aquatic ecosystem until now.

  7. Drainage pits in cohesionless materials: implications for surface of Phobos.

    PubMed

    Horstman, K C; Melosh, H J

    1989-09-10

    Viking orbiter images show grooves and chains of pits crossing the surface of Phobos, many of which converge toward the large crater Stickney or its antipode. Although it has been proposed that the pits and grooves are chains of secondary craters, their morphology and geometric relations suggest that they are the surface traces of fractures in the underlying solid body of Phobos. Several models have been proposed to explain the pits, of which the most plausible are gas venting and drainage of regolith into open fractures. the latter mechanism is best supported by the image data and is the mechanism studied in this investigation. Drainage pits and fissures are modeled experimentally by using two rigid substrate plates placed edge to edge and covered by uniform thicknesses of dry fragmental debris (simulated regolith). Fracture extension is simulated by drawing the plates apart, allowing drainage of regolith into the newly created void. A typical drainage experiment begins with a shallow depression on the surface of the regolith, above the open fissure. Increased drainage causes local drainage pits to form; continued drainage causes the pits to coalesce, forming a cuspate groove. The resulting experimental patterns of pits and grooves have pronounced similarities to those observed on Phobos. Characteristics such as lack of raised rims, linearity of grooves and chains of pits, uniform spacing of pits, and progression from discrete pits to cuspate grooves are the same in the experiments and on Phobos. In contrast, gas-venting pits occur in irregular chains and have raised rims. These experiments thus indicate that the Phobos grooves and pits formed as drainage structures. The pit spacing in an experiment is measured at the time that the maximum number of pits forms, prior to groove development. The average pit spacing is compared to the regolith thickness for each material. Regression line fits indicate that the average spacing of drainage pits in unconsolidated

  8. Drainage pits in cohesionless materials: implications for surface of Phobos.

    PubMed

    Horstman, K C; Melosh, H J

    1989-09-10

    Viking orbiter images show grooves and chains of pits crossing the surface of Phobos, many of which converge toward the large crater Stickney or its antipode. Although it has been proposed that the pits and grooves are chains of secondary craters, their morphology and geometric relations suggest that they are the surface traces of fractures in the underlying solid body of Phobos. Several models have been proposed to explain the pits, of which the most plausible are gas venting and drainage of regolith into open fractures. the latter mechanism is best supported by the image data and is the mechanism studied in this investigation. Drainage pits and fissures are modeled experimentally by using two rigid substrate plates placed edge to edge and covered by uniform thicknesses of dry fragmental debris (simulated regolith). Fracture extension is simulated by drawing the plates apart, allowing drainage of regolith into the newly created void. A typical drainage experiment begins with a shallow depression on the surface of the regolith, above the open fissure. Increased drainage causes local drainage pits to form; continued drainage causes the pits to coalesce, forming a cuspate groove. The resulting experimental patterns of pits and grooves have pronounced similarities to those observed on Phobos. Characteristics such as lack of raised rims, linearity of grooves and chains of pits, uniform spacing of pits, and progression from discrete pits to cuspate grooves are the same in the experiments and on Phobos. In contrast, gas-venting pits occur in irregular chains and have raised rims. These experiments thus indicate that the Phobos grooves and pits formed as drainage structures. The pit spacing in an experiment is measured at the time that the maximum number of pits forms, prior to groove development. The average pit spacing is compared to the regolith thickness for each material. Regression line fits indicate that the average spacing of drainage pits in unconsolidated

  9. Detecting pits in tart cherries by hyperspectral transmission imaging

    NASA Astrophysics Data System (ADS)

    Qin, Jianwei; Lu, Renfu

    2004-11-01

    The presence of pits in processed cherry products causes safety concerns for consumers and imposes potential liability for the food industry. The objective of this research was to investigate a hyperspectral transmission imaging technique for detecting the pit in tart cherries. A hyperspectral imaging system was used to acquire transmission images from individual cherry fruit for four orientations before and after pits were removed over the spectral region between 450 nm and 1,000 nm. Cherries of three size groups (small, intermediate, and large), each with two color classes (light red and dark red) were used for determining the effect of fruit orientation, size, and color on the pit detection accuracy. Additional cherries were studied for the effect of defect (i.e., bruises) on the pit detection. Computer algorithms were developed using the neural network (NN) method to classify the cherries with and without the pit. Two types of data inputs, i.e., single spectra and selected regions of interest (ROIs), were compared. The spectral region between 690 nm and 850 nm was most appropriate for cherry pit detection. The NN with inputs of ROIs achieved higher pit detection rates ranging from 90.6% to 100%, with the average correct rate of 98.4%. Fruit orientation and color had a small effect (less than 1%) on pit detection. Fruit size and defect affected pit detection and their effect could be minimized by training the NN with properly selected cherry samples.

  10. Pitting and Intergranular Corrosion Resistance of AISI Type 301LN Stainless Steels

    NASA Astrophysics Data System (ADS)

    Ningshen, S.; Kamachi Mudali, U.

    2010-03-01

    The pitting and intergranular corrosion (IGC) resistance of AISI type 301LN stainless steels were evaluated using ASTM methods, anodic polarization, and electrochemical impedance techniques. The IGC results indicated that the microstructure of the samples after sensitization heat treatment at 675 °C for 1 h shows step or dual structure for both imported and indigenous materials indicating insignificant Cr23C6 precipitation. The results of immersion tests in boiling 6% copper sulfate + 16% sulfuric acid + copper solution for 24 h followed by the bend test (ASTM A262 Practice-E method) indicated no crack formation in any of the tested specimens. Pitting corrosion resistance carried out in 6% FeCl3 solution at different temperatures of 22 ± 2 and 50 ± 2 °C (ASTM G 48) up to the period of 72 h revealed pitting corrosion attack in all the investigated alloys. The potentiodynamic anodic polarization results in 0.5 M NaCl revealed variation in passive current density and pitting potential depending on the alloy chemistry and metallurgical condition. The passive film properties studied by electrochemical impedance spectroscopy (EIS) correlated well with the polarization results. The x-ray diffraction (XRD) results revealed the presence of austenite (γ) and martensite (α') phases depending on the material condition. The suitability of three indigenously developed AISI type 301LN stainless steels were compared with imported type 301LN stainless steel and the results are highlighted in this article.

  11. Trichloroacetic acid in the vegetation of polluted and remote areas of both hemispheres—Part II: salt lakes as novel sources of natural chlorohydrocarbons

    NASA Astrophysics Data System (ADS)

    Weissflog, Ludwig; Elansky, Nikolai; Putz, Erich; Krueger, Gert; Lange, Christian A.; Lisitzina, Lida; Pfennigsdorff, Andrea

    One of the issues provided for by the 1993 existing substances regulation (793/93/EEC) is the assessment of the environmental risk emanating from waste materials. One such material is the highly volatile substance perchloroethene (PER; TECE). PER is produced in large quantities all over the world by the chemical industry. There are many industrial processes in which PER escapes into the environment, especially the atmosphere. It has since been proven that after entering plants via the air/leaf pathway, airborne PER can be metabolised into the phytotoxic substance trichloroacetic acid. However our own studies detected relatively high levels of TCA in environmental compartments in regions far away from industry which cannot be explained by the anthropogenic input of airborne substances into the relevant ecosystems. This indicates that natural PER emittents also exist and must be identified, in order to find out more about the global spread of PER. This paper reports on the findings of related fieldwork in the Kalmykian Steppe. This area of steppe in southern Russia spans an area extending west-to-east from the Black Sea and the Caspian Sea and north-to-south between the Greater Caucasus and Volgograd. The main aim of the experiments in the Kalmykian Steppe was to study water from lakes, rivers and springs with differing levels of salinity. The concentrations of the chlorinated hydrocarbons (VCHCs) chloroform (CHCl 3), tetrachloromethane (CCl 4), 1,1,1-trichloroethane (1,1,1-C 2H 3Cl 3), trichloroethene (TRI; C 2HCl 3), tetrachloroethene (PER; C 2Cl 4) and TCA in these waters were measured, along with the levels of cations and anions and the pH-value of the waters. The measurements indicate that in particular water from salt lakes located in semiarid/arid areas of the study region must be considered as new types of natural emittents of PER and other chlorinated hydrocarbons as well as trichloroacetic acid. Furthermore, attention is drawn to ecological impacts

  12. Orientation dependence and bonding during pitting corrosion of HCP metals.

    SciTech Connect

    Lillard, Robert Scott

    2002-01-01

    The orientation dependence of pitting in single crystal beryllium (Be) is compared to the observations for single crystal zinc (Zn) reported by other investigators. The pit walls in stable propagating pits for prism planes were always square; in the (ioio) surface the walls were normal to the [0001] and [{bar 1}2{bar 1}0] directions while in the (110) surface the walls were normal to the [0001] and [{bar 1}100] directions. In addition, for the (ioio) and (11{bar 2}0) surfaces the pit interiors were characterized by crystallographically oriented parallel plates of unattacked Be. The orientation of these lamella was quite different than those observed in Zn. To explain this difference, the electron density distributions in the metal lattices are analyzed. A conceptual model for crystallographic pitting is introduced. In this model it is proposed that the crystallographic pits observed in single crystal hcp metals reflects the bond energy in the lattice.

  13. Coordinate Measuring Machine Pit Artifact Inspection Procedure

    SciTech Connect

    Montano, Joshua D.

    2012-07-31

    The goal of this document is to outline a procedure for dimensional measurement of Los Alamos National Laboratory's CMM Pit Artifact. This procedure will be used by the Manufacturing Practice's Inspection Technology Subgroup of the Interagency Manufacturing Operations Group and Joint Operations Weapon Operations Group (IMOG/JOWOG 39) round robin participants. The intent is to assess the state of industry within the Nuclear Weapons Complex for measurements made on this type of part and find which current measurement strategies and techniques produce the best results.

  14. The Pit and the Safety Pendulum

    SciTech Connect

    Nitschke, Robert Leon; Ramos, Amadeo Gabriel

    2000-11-01

    The hypothesis of this paper is that the safety analysis pendulum has swung considerably in the direction of increasingly complex and lengthy safety evaluations and intense reviews during the past 30 years. The test of this hypothesis will be a review of the safety analysis conducted for various activities associated with the retrieval of transuranic radioactive waste from burial pits at a National Laboratory site over a span of 30 years. The examination will focus on the safety aspects and the safety analysis that was conducted for the projects. At the conclusion of this examination, the paper will identify five reasons why the changes have taken place.

  15. Acidification in the Adirondacks: Defining the Biota in trophic Levels of 30 Chemically Diverse Acid-Impacted Lakes

    EPA Science Inventory

    The Adirondack Mountains in New York State have a varied surficial geology and chemically diverse surface waters that are among the most impacted by acid deposition in the U.S. No single Adirondack investigation has been comprehensive in defining the effects of acidification on ...

  16. Analysis and cleaning of dirty W48 pits

    SciTech Connect

    LeMay, J.D.

    1996-04-01

    This presentation will summarize the results of an investigation of a dirty W48 pit and the subsequent development of a process for cleaning this class of pits in preparation for long-term storage. The residues of the dirty pit were analyzed for chemical identification and evidence of species known to promote corrosion of the metal cladding. The cleaning process was developed to reduce the potential for future corrosion during long-term storage.

  17. Species composition of fish communities in northern Wisconsin lakes: Relation to pH

    USGS Publications Warehouse

    Wiener, J.G.; Rago, P.J.; Eilers, J.M.; Hendrey, G.R.

    1984-01-01

    Fish communities in circumneutral Wisconsin lakes contained significantly more species than did those in acidic lakes (pH 5.1-6.0). Common, as well as rare, species occurred with lower frequency in acidic lakes than in circumneutral lakes. Certain taxa, such as minnows and darters, were either absent or rare in the acidic lakes, probably because of pH-related stress. The differences in species composition and richness of fish communities between acidic and circumneutral lakes did not appear to be related to differences in physical habitat characteristics, past fish migrations or productivity between the two lake groups.

  18. 18. DETAIL, INSPECTION PIT Delaware, Lackawanna & Western Railroad ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    18. DETAIL, INSPECTION PIT - Delaware, Lackawanna & Western Railroad Freight & Rail Yard, Multiple Unit Light Inspection Shed, New Jersey Transit Hoboken Terminal Rail Yard, Hoboken, Hudson County, NJ

  19. Lessons Learned from Pit Viper System Deployment

    SciTech Connect

    Catalan, Michael A.; Alzheimer, James M.; Valdez, Patrick LJ; Bailey, Sharon A.; Baker, Carl P.

    2002-04-11

    Tele-operated and robotic systems operated in unstructured field environments pose unique challenges for tool design. Since field tasks are not always well defined and the robot work area usually cannot be designed for ease of operation, the tools must be versatile. It's important to carefully consider the orientation of the grip the robot takes on the tool, as it's not easily changed in the field. The stiffness of the robot and the possibility of robot positioning errors encourages the use of non-contact or minimal-contact tooling. While normal hand tools can usually be modified for use by the robot, this is not always the most effective approach. It's desirable to have tooling that is relatively independent of the robot; in this case, the robot places the tool near the desired work location and the tool performs its task relatively independently. Here we consider the adaptation of a number of tools for cleanup of a radioactively contaminated piping junction and valve pit. The tasks to be considered are debris removal (small nuts and bolts and pipe up to 100 mm in diameter), size reduction, surface cleaning, and support of past practice crane-based methods for working in the pits.

  20. Introduction to Pits and Weapons Systems (U)

    SciTech Connect

    Kautz, D.

    2012-07-02

    A Nuclear Explosive Package includes the Primary, Secondary, Radiation Case and related components. This is the part of the weapon that produces nuclear yield and it converts mechanical energy into nuclear energy. The pit is composed of materials that allow mechanical energy to be converted to electromagnetic energy. Fabrication processes used are typical of any metal fabrication facility: casting, forming, machining and welding. Some of the materials used in pits include: Plutonium, Uranium, Stainless Steel, Beryllium, Titanium, and Aluminum. Gloveboxes are used for three reasons: (1) Protect workers and public from easily transported, finely divided plutonium oxides - (a) Plutonium is very reactive and produces very fine particulate oxides, (b) While not the 'Most dangerous material in the world' of Manhattan Project lore, plutonium is hazardous to health of workers if not properly controlled; (2) Protect plutonium from reactive materials - (a) Plutonium is extremely reactive at ambient conditions with several components found in air: oxygen, water, hydrogen, (b) As with most reactive metals, reactions with these materials may be violent and difficult to control, (c) As with most fabricated metal products, corrosion may significantly affect the mechanical, chemical, and physical properties of the product; and (3) Provide shielding from radioactive decay products: {alpha}, {gamma}, and {eta} are commonly associated with plutonium decay, as well as highly radioactive materials such as {sup 241}Am and {sup 238}Pu.

  1. Lake Constance

    Atmospheric Science Data Center

    2013-04-17

    article title:  Lake Constance, Europe     View ... This Multi-angle Imaging SpectroRadiometer (MISR) image of Lake Constance covers an area measuring 355 kilometers x 287 kilometers, and ... wastewater and fertilizers. This leads to overproduction of algae and aquatic plants, exhaustion of available oxygen, loss of some fish ...

  2. High levels of perfluoroalkyl acids in eggs and embryo livers of great cormorant (Phalacrocorax carbo sinensis) and herring gull (Larus argentatus) from Lake Vänern, Sweden.

    PubMed

    Nordén, Marcus; Berger, Urs; Engwall, Magnus

    2013-11-01

    In the eggs and developing chick livers in the two wild bird species, great cormorant and herring gull, the concentrations of a range of 15 perfluoroalkyl acids (PFAAs) were determined. Eggs of the two species were collected from Lake Vänern, Sweden, and analysed either as undeveloped egg (whole egg or separated into yolk and albumen) or incubated until start of the hatching process when the chick liver was removed and analysed. High levels of PFAAs were found in all matrixes except albumen. The predominant PFAA was perfluorooctane sulfonate (PFOS), which was found in the μg/g wet weight (ww) range in some samples of cormorant whole egg, yolk and liver and herring gull egg yolk and liver. The average concentration in yolk was 1,506 ng/g ww in cormorant and 589 ng/g ww in herring gull. The average liver concentrations of PFOS were 583 ng/g ww in cormorant and 508 ng/g ww in herring gull. At these concentrations, biochemical effects in the developing embryo or effects on embryo survival cannot be ruled out. For perfluoroalkyl carboxylates (PFCAs), the liver/egg and liver/yolk concentration ratios increased with PFCA chain length in cormorant but not in herring gull, indicating that chain length could possibly affect egg-to-liver transfer of PFCAs and that species differences may exist.

  3. High levels of perfluoroalkyl acids in eggs and embryo livers of great cormorant (Phalacrocorax carbo sinensis) and herring gull (Larus argentatus) from Lake Vänern, Sweden.

    PubMed

    Nordén, Marcus; Berger, Urs; Engwall, Magnus

    2013-11-01

    In the eggs and developing chick livers in the two wild bird species, great cormorant and herring gull, the concentrations of a range of 15 perfluoroalkyl acids (PFAAs) were determined. Eggs of the two species were collected from Lake Vänern, Sweden, and analysed either as undeveloped egg (whole egg or separated into yolk and albumen) or incubated until start of the hatching process when the chick liver was removed and analysed. High levels of PFAAs were found in all matrixes except albumen. The predominant PFAA was perfluorooctane sulfonate (PFOS), which was found in the μg/g wet weight (ww) range in some samples of cormorant whole egg, yolk and liver and herring gull egg yolk and liver. The average concentration in yolk was 1,506 ng/g ww in cormorant and 589 ng/g ww in herring gull. The average liver concentrations of PFOS were 583 ng/g ww in cormorant and 508 ng/g ww in herring gull. At these concentrations, biochemical effects in the developing embryo or effects on embryo survival cannot be ruled out. For perfluoroalkyl carboxylates (PFCAs), the liver/egg and liver/yolk concentration ratios increased with PFCA chain length in cormorant but not in herring gull, indicating that chain length could possibly affect egg-to-liver transfer of PFCAs and that species differences may exist. PMID:23463275

  4. Electrokinetic demonstration at the unlined chromic acid pit

    SciTech Connect

    Lindgren, E.R.; Hankins, M.G.; Mattson, E.D.; Duda, P.M.

    1998-01-01

    Heavy-metal contaminated soils are a common problem at Department of Energy (DOE)-operated sites and privately owned facilities throughout the nation. One emerging technology which can remove heavy metals from soil in situ is electrokinetics. To conduct electrokinetic (EK) remediation, electrodes are implanted into the ground, and a direct current is imposed between the electrodes. Metal ions dissolved in the soil pore water migrate towards an electrode where they can be removed. The electrokinetic program at Sandia National Laboratories (SNL) has been focusing on electrokinetic remediation for unsaturated soils. A patent was awarded for an electrokinetic electrode system designed at SNL for applications to unsaturated soils. Current research described in this report details an electrokinetic remediation field demonstration of a chromium plume that resides in unsaturated soil beneath the SNL Chemical Waste Landfill (CWL). This report describes the processes, site investigation, operation and monitoring equipment, testing procedures, and extraction results of the electrokinetic demonstration. This demonstration successfully removed chromium contamination in the form of chromium(VI) from unsaturated soil at the field scale. After 2700 hours of operation, 600 grams of Cr(VI) was extracted from the soil beneath the SNL CWL in a series of thirteen tests. The contaminant was removed from soil which has moisture contents ranging from 2 to 12 weight percent. This demonstration was the first EK field trial to successfully remove contaminant ions from and soil at the field scale. Although the new patented electrode system was successful in removing an anionic contaminant (i.e., chromate) from unsaturated sandy soil, the electrode system was a prototype and has not been specifically engineered for commercialization. A redesign of the electrode system as indicated by the results of this research is suggested for future EK field trials.

  5. [Microbial diversity and ammonia-oxidizing microorganism of a soil sample near an acid mine drainage lake].

    PubMed

    Liu, Ying; Wang, Li-Hua; Hao, Chun-Bo; Li, Lu; Li, Si-Yuan; Feng, Chuan-Ping

    2014-06-01

    The main physicochemical parameters of the soil sample which was collected near an acid mine drainage reservoir in Anhui province was analyzed. The microbial diversity and community structure was studied through the construction of bacteria and archaea 16S rRNA gene clone libraries and ammonia monooxygenase gene clone library of archaea. The functional groups which were responsible for the process of ammonia oxidation were also discussed. The results indicated that the soil sample had extreme low pH value (pH < 3) and high ions concentration, which was influenced by the acid mine drainage (AMD). All the 16S rRNA gene sequences of bacteria clone library fell into 11 phyla, and Acidobacteria played the most significant role in the ecosystem followed by Verrucomicrobia. A great number of acidophilic bacteria existed in the soil sample, such as Candidatus Koribacter versatilis and Holophaga sp.. The archaea clone library consisted of 2 phyla (Thaumarchaeota and Euryarchaeota). The abundance of Thaumarchaeota was remarkably higher than Euryarchaeota. The ammonia oxidation in the soil environment was probably driven by ammonia-oxidizing archaea, and new species of ammonia-oxidizing archaea existed in the soil sample.

  6. Numerical modelling of the groundwater inflow to an advancing open pit mine: Kolahdarvazeh pit, Central Iran.

    PubMed

    Bahrami, Saeed; Doulati Ardejani, Faramarz; Aslani, Soheyla; Baafi, Ernest

    2014-12-01

    The groundwater inflow into a mine during its life and after ceasing operations is one of the most important concerns of the mining industry. This paper presents a hydrogeological assessment of the Irankuh Zn-Pb mine at 20 km south of Esfahan and 1 km northeast of Abnil in west-Central Iran. During mine excavation, the upper impervious bed of a confined aquifer was broken and water at high-pressure flowed into an open pit mine associated with the Kolahdarvazeh deposit. The inflow rates were 6.7 and 1.4 m(3)/s at the maximum and minimum quantities, respectively. Permeability, storage coefficient, thickness and initial head of the fully saturated confined aquifer were 3.5 × 10(-4) m/s, 0.2, 30 m and 60 m, respectively. The hydraulic heads as a function of time were monitored at four observation wells in the vicinity of the pit over 19 weeks and at an observation well near a test well over 21 h. In addition, by measuring the rate of pumping out from the pit sump, at a constant head (usually equal to height of the pit floor), the real inflow rates to the pit were monitored. The main innovations of this work were to make comparison between numerical modelling using a finite element software called SEEP/W and actual data related to inflow and extend the applicability of the numerical model. This model was further used to estimate the hydraulic heads at the observation wells around the pit over 19 weeks during mining operations. Data from a pump-out test and observation wells were used for model calibration and verification. In order to evaluate the model efficiency, the modelling results of inflow quantity and hydraulic heads were compared to those from analytical solutions, as well as the field data. The mean percent error in relation to field data for the inflow quantity was 0.108. It varied between 1.16 and 1.46 for hydraulic head predictions, which are much lower values than the mean percent errors resulted from the analytical solutions (from 1.8 to 5

  7. Numerical modelling of the groundwater inflow to an advancing open pit mine: Kolahdarvazeh pit, Central Iran.

    PubMed

    Bahrami, Saeed; Doulati Ardejani, Faramarz; Aslani, Soheyla; Baafi, Ernest

    2014-12-01

    The groundwater inflow into a mine during its life and after ceasing operations is one of the most important concerns of the mining industry. This paper presents a hydrogeological assessment of the Irankuh Zn-Pb mine at 20 km south of Esfahan and 1 km northeast of Abnil in west-Central Iran. During mine excavation, the upper impervious bed of a confined aquifer was broken and water at high-pressure flowed into an open pit mine associated with the Kolahdarvazeh deposit. The inflow rates were 6.7 and 1.4 m(3)/s at the maximum and minimum quantities, respectively. Permeability, storage coefficient, thickness and initial head of the fully saturated confined aquifer were 3.5 × 10(-4) m/s, 0.2, 30 m and 60 m, respectively. The hydraulic heads as a function of time were monitored at four observation wells in the vicinity of the pit over 19 weeks and at an observation well near a test well over 21 h. In addition, by measuring the rate of pumping out from the pit sump, at a constant head (usually equal to height of the pit floor), the real inflow rates to the pit were monitored. The main innovations of this work were to make comparison between numerical modelling using a finite element software called SEEP/W and actual data related to inflow and extend the applicability of the numerical model. This model was further used to estimate the hydraulic heads at the observation wells around the pit over 19 weeks during mining operations. Data from a pump-out test and observation wells were used for model calibration and verification. In order to evaluate the model efficiency, the modelling results of inflow quantity and hydraulic heads were compared to those from analytical solutions, as well as the field data. The mean percent error in relation to field data for the inflow quantity was 0.108. It varied between 1.16 and 1.46 for hydraulic head predictions, which are much lower values than the mean percent errors resulted from the analytical solutions (from 1.8 to 5

  8. Feeding patterns of migratory and non-migratory fourth instar larvae of two coexisting Chaoborus species in an acidic and metal contaminated lake: Importance of prey ingestion rate in predicting metal bioaccumulation

    USGS Publications Warehouse

    Croteau, M.-N.; Hare, L.; Marcoux, P.

    2003-01-01

    We studied diel variations in the feeding habits and migratory behaviors of two coexisting Chaoborus species in an acidic and metal contaminated lake (Lake Turcotte, QC, Canada). We found that although the zooplankton community was dominated by rotifers, both Chaoborus species fed mostly on chironomids and crustaceans despite the relatively low abundance of these prey types in the lake plankton. Chaoborus americanus larvae fed on those of Chaoborus punctipennis, but not vice versa. The non-migratory species (C. americanus) fed throughout the day and night whereas the migratory species (C. punctipennis) fed only at night while in the water column. The larger-bodied C. americanus consumed more prey and had a more diverse diet than did the smaller-bodied C. punctipennis. Differences in feeding habits between the Chaoborus species inhabiting Lake Turcotte (prey biomass, prey types) likely explain in part their ability to coexist. Attempts to predict Cd in the Chaoborus species using our measurements of Cd in their prey and their prey ingestion rates met with mixed success; although we correctly predicted higher Cd concentrations for C. americanus larvae than for C. punctipennis larvae, we under-predicted absolute Cd concentrations. We suggest that studies such as ours that are based on analyses of gut contents of larvae collected at intervals of 4h or longer likely underestimate prey ingestion rates.

  9. Hydrology of Lake Butler, Orange County, Florida

    USGS Publications Warehouse

    Smoot, James L.; Schiffer, Donna M.

    1984-01-01

    Lake Butler is one of the lakes that collectively make up the Butler chain of lakes in the headwaters of the Kissimmee River, Florida. The bottom configuration of the lake is typical of relict karst features formed during lower stages in sea level. The top of the Floridan aquifer is 50 to 100 feet below the land surface. The drainage area of Lake Butler is approximately 14.5 sq mi and is comprised of sub-basins of other lakes in the vicinity. Surface outflow from Lake Butler is generally southward to Cypress Creek, a tributary of the Kissimmee River. The extremes in lake stage for the period 1933-81 are 94.67 ft on June 23, 1981 and 101.78 ft on September 13, 1960. The median lake stage for this period was 99.28 ft above sea level. The quality of water in Lake Butler is excellent, based on studies of physical, chemical, and biological conditions by the Orange County Pollution Control Department. The lake water is slightly acidic and soft (48 mg/L hardness as calcium carbonate). Pesticides in water were below detection levels at two sites sampled in the lake, but were detected in the bottom sediments. (USGS)

  10. 103. ARAIII. Looking down into GCRE reactor pit as it ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    103. ARA-III. Looking down into GCRE reactor pit as it was being modified for further ML-1 testing. Shows bellows assembly, men working in pit, spiral staircase. May 20, 1965. Ineel photo no. 65-2762. Photographer: Farmer. - Idaho National Engineering Laboratory, Army Reactors Experimental Area, Scoville, Butte County, ID

  11. 241-AY-102 Leak Detection Pit Drain Line Inspection Report

    SciTech Connect

    Boomer, Kayle D.; Engeman, Jason K.; Gunter, Jason R.; Joslyn, Cameron C.; Vazquez, Brandon J.; Venetz, Theodore J.; Garfield, John S.

    2014-01-20

    This document provides a description of the design components, operational approach, and results from the Tank AY-102 leak detection pit drain piping visual inspection. To perform this inspection a custom robotic crawler with a deployment device was designed, built, and operated by IHI Southwest Technologies, Inc. for WRPS to inspect the 6-inch leak detection pit drain line.

  12. 7 CFR 52.807 - Freedom from pits.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... United States Standards for Grades of Frozen Red Tart Pitted Cherries Factors of Quality § 52.807 Freedom... substantially free from any adhering sirup, sugar, or other packing medium. (c) (A) Classification. Frozen red... for this classification specified in Table I. (d) (B) Classification. Frozen red tart pitted...

  13. 7 CFR 52.807 - Freedom from pits.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... means pitted cherries that are substantially free from any adhering sirup, sugar, or other packing... may be present does not exceed the allowances for this classification specified in Table I. (d) (B... in Table I. (e) (C) Classification. Frozen red tart pitted cherries that are fairly free from...

  14. 7 CFR 52.807 - Freedom from pits.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... substantially free from any adhering sirup, sugar, or other packing medium. (c) (A) Classification. Frozen red... for this classification specified in Table I. (d) (B) Classification. Frozen red tart pitted cherries... pits that may be present does not exceed the number specified in Table I. (e) (C)...

  15. Modelling the mechanical behaviour of pit membranes in bordered pits with respect to cavitation resistance in angiosperms

    PubMed Central

    Tixier, Aude; Herbette, Stephane; Jansen, Steven; Capron, Marie; Tordjeman, Philippe; Cochard, Hervé; Badel, Eric

    2014-01-01

    Background and Aims Various correlations have been identified between anatomical features of bordered pits in angiosperm xylem and vulnerability to cavitation, suggesting that the mechanical behaviour of the pits may play a role. Theoretical modelling of the membrane behaviour has been undertaken, but it requires input of parameters at the nanoscale level. However, to date, no experimental data have indicated clearly that pit membranes experience strain at high levels during cavitation events. Methods Transmission electron microscopy (TEM) was used in order to quantify the pit micromorphology of four tree species that show contrasting differences in vulnerability to cavitation, namely Sorbus aria, Carpinus betulus, Fagus sylvatica and Populus tremula. This allowed anatomical characters to be included in a mechanical model that was based on the Kirchhoff–Love thin plate theory. A mechanistic model was developed that included the geometric features of the pits that could be measured, with the purpose of evaluating the pit membrane strain that results from a pressure difference being applied across the membrane. This approach allowed an assessment to be made of the impact of the geometry of a pit on its mechanical behaviour, and provided an estimate of the impact on air-seeding resistance. Key Results The TEM observations showed evidence of residual strains on the pit membranes, thus demonstrating that this membrane may experience a large degree of strain during cavitation. The mechanical modelling revealed the interspecific variability of the strains experienced by the pit membrane, which varied according to the pit geometry and the pressure experienced. The modelling output combined with the TEM observations suggests that cavitation occurs after the pit membrane has been deflected against the pit border. Interspecific variability of the strains experienced was correlated with vulnerability to cavitation. Assuming that air-seeding occurs at a given pit membrane

  16. Characterization and expression analysis of FRUITFULL- and SHATTERPROOF-like genes from peach (Prunus persica) and their role in split-pit formation.

    PubMed

    Tani, Eleni; Polidoros, Alexios N; Tsaftaris, Athanasios S

    2007-05-01

    The fruit canning industry processes large quantities of the clingstone varieties of peach (Prunus persica L. Batch). The occurrence of split-pit formation--the opening of the pit and sometimes splitting of the fruit--causes deterioration of canned fruit quality. The frequency of split-pit formation is influenced by genetic and environmental factors. To increase understanding of the molecular mechanisms underlying split-pit formation in peach, we cloned and characterized the PPERFUL and PPERSHP genes that are homologues to the genes FRUITFULL and SHATTERPROOF, respectively, which are involved in fruit splitting (pod shattering) in Arabidopsis thaliana. The deduced amino acid sequences of the two genes had high homology with members of the MADS-box family of transcription factors, and particularly with other members of the FUL-like family of A-type MADS-box proteins and PLENA-like family of C-type MADS-box proteins, respectively. PPERFUL and PPERSHP were expressed throughout fruit development from full anthesis until fruit harvest. Differences in the mRNA abundance of each gene were compared in a split-pit sensitive and a split-pit resistant variety. Results suggested that temporal regulation of PPERFUL and PPERSHP expression may have an effect on the split-pit process.

  17. Mapping sand and gravel pits in the Patuxent River watershed

    NASA Technical Reports Server (NTRS)

    Schmidt, T. J.; Witt, R. G.

    1981-01-01

    LANDSAT data from July 1973 and June 1978 for the Patuxent River Watershed of Maryland were processed in an effort to devise an economical method of monitoring the reclamation of sand and gravel pits. ASTEP-II and IDIMS software were utilized to derive signatures for sand and gravel pits and other land use/land cover types. Both unsupervised and supervised classifications of the two data sets were produced. Resultant statistics and color output products were compared in order to determine the extent of reclamation and expansion of sand and gravel pits over the five-year time span and to check the locations of more recent sand and gravel pits. Preliminary results indicate that, for a selected northern sub-acre, signatures derived for sand and gravel pits were nearly 90 percent accurate.

  18. Crevice and pitting corrosion behavior of stainless steels in seawater

    SciTech Connect

    Zaragoza-Ayala, A.E.; Orozco-Cruz, R.

    1999-11-01

    Pitting and crevice corrosion tests in natural seawater were performed on a series of stainless steels (i.e., S31603, N08904, S32304, S31803, S32520, N08925 and S31266) in order to determine their resistance to these types of localized corrosion. Open circuit potential (OCP) measurements for these alloys show for short exposure times an ennoblement in the OCP. After a certain time, occasional fall and rise in the OCP values was observed, which can be related to nucleation and repassivation of pits and/or crevices on the metal surface. Analysis of the electrochemical behavior and microscopic observations shows that only S31603 and S32304 alloys were susceptible to crevice and pitting corrosion, whereas the remaining alloys exhibited good resistance. Pitting potentials determined by the potentiodynamic technique also show S3 1603 and S32304 are susceptible to pitting corrosion under the experimental conditions used in this work.

  19. Microbial contents of soil from fire pits

    NASA Astrophysics Data System (ADS)

    Moon, K.; Esparza, V.; de Sandre, J.; Cheney, S.; Anderson, A.; White, M. A.

    2006-12-01

    Forest fires generate polycylic aromatic hydrocarbons (PAHs) that can lead to carcinogenic compounds, which are potential health risks. PAHs can be degraded to water and carbon dioxide by certain soil microbes. Thus, during participation in a NASA-funded summer research experience at Utah State University, our high school student team sampled soils from a month-old fire pit in which plant materials had been burnt. We detected in soil samples, from surface, 10 and 20 cm depths, microbes that would grow on a defined minimal medium source. Other microbes were cultured from the roots of plants that had established at the fire pit. A diversity of microbes was present in all samples based on visible differences in cell shape and color. It was surprising that the surface ash, although exposed to sunlight over the month interval, had culturable colonies. Many of these culturable bacteria were pigmented perhaps as a protection against UV radiation from the sun. We searched for genes in the microbes that encoded enzymes called dioxygenases that in other bacteria are involved in degradation of PAHs. This test involved using polymerase chain reactions to detect the genes. PCR products were found in two of the fifteen isolates tested although their sizes differed from the control gene product from a PAH-degrading mycobacterium isolate. These results suggest that the soils did contain microbes with the possible potential to alter the PAH compounds generated from vegetation fires. Our findings serve as a starting point for future studies looking at recovery and remediation of fired acreages.

  20. Numerical Ages of Holocene Tributary Debris Fans Inferred from Dissolution Pitting on Carbonate Boulders in the Grand Canyon of Arizona

    NASA Astrophysics Data System (ADS)

    Hereford, Richard; Thompson, Kathryn S.; Burke, Kelly J.

    1998-09-01

    Carbonate boulders transported down steep tributary channels by debris flow came to rest on Holocene debris fans beside the Colorado River in Grand Canyon National Park. Weakly acidic rainfall and the metabolic activity of blue-green algae have produced roughly hemispheric dissolution pits as much as 2-cm deep on the initially smooth surfaces of the boulders. The average depth of dissolution pits increases with relative age of fan surfaces. The deepening rate averages 2.4 mm/1000 yr (standard error = 0.2 mm/1000 yr), as calculated from several radiometrically dated surfaces and an archeological structure. This linear rate, which appears constant over at least the past 3000 yr, is consistent with field relations limiting the maximum age of the fans and with the physical chemistry of limestone dissolution. Dissolution-pit measurements ( n= 6973) were made on 617 boulders on 71 fan surfaces at the 26 largest debris fans in Grand Canyon. Among these fan surfaces, the average pit depth ranges from 1.2 to 17.4 mm, and the resulting pit dissolution ages range from 500 to 7300 cal yr B.P. Most (75%) surfaces are younger than 3000 yr, probably because of removal of older debris fans by the Colorado River. Many of the ages are close to 800, 1600, 2300, 3100, or 4300 cal yr B.P. If not the result of differential preservation of fan surfaces, this clustering implies periods of heightened debris-flow activity and increased precipitation.

  1. Numerical ages of Holocene tributary debris fans inferred from dissolution pitting on carbonate boulders in the Grand Canyon of Arizona

    USGS Publications Warehouse

    Hereford, R.; Thompson, K.S.; Burke, K.J.

    1998-01-01

    Carbonate boulders transported down steep tributary channels by debris flow came to rest on Holocene debris fans beside the Colorado River in Grand Canyon National Park. Weakly acidic rainfall and the metabolic activity of blue-green algae have produced roughly hemispheric dissolution pits as much as 2-cm deep on the initially smooth surfaces of the boulders. The average depth of dissolution pits increases with relative age of fan surfaces. The deepening rate averages 2.4 mm/1000 yr (standard error = 0.2 mm/1000 yr), as calculated from several radiometrically dated surfaces and an archeological structure. This linear rate, which appears constant over at least the past 3000 yr, is consistent with field relations limiting the maximum age of the fans and with the physical chemistry of limestone dissolution. Dissolution-pit measurements (n = 6973) were made on 617 boulders on 71 fan surfaces at the 26 largest debris fans in Grand Canyon. Among these fan surfaces, the average pit depth ranges from 1.2 to 17.4 mm, and the resulting pit dissolution ages range from 500 to 7300 cal yr B.P. Most (75%) surfaces are younger than 3000 yr, probably because of removal of older debris fans by the Colorado River. Many of the ages are close to 800, 1600, 2300, 3100, or 4300 cal yr B.P. If not the result of differential preservation of fan surfaces, this clustering implies periods of heightened debris-flow activity and increased precipitation.

  2. A Topographic Analysis of Lunar Pit Craters Using LOLA

    NASA Astrophysics Data System (ADS)

    Malinski, P. T.; Milam, K. A.

    2014-12-01

    Pit craters have been a recent interest in the impact crater community due to their elusive formational mechanism(s) and their variable morphologies on different bodies. Pit craters have been observed on multiple planetary bodies and currently efforts are underway to characterize these crater types. In this work we focused on finding and evaluating pitted craters and their morphologic habits on the lunar surface to better constrain pit crater formation on a relatively dry body (compared to Mars and Ganymede). The study area ranged across the entire lunar surface from -20 to 50 degree latitudes and included both highland and maria terrains. The diameter range of the crater population evaluated was 20 - 60 km. The diameter range was chosen to include complex crater morphology (minimum diameter ~20 km) but to not include larger impacts (>60 km) to prevent misinterpretation of central regions. An overall population of 1490 craters were evaluated, of which 115 craters were characterized as pit craters. The LOLA data set along with NAC+WAC, Clementine visible imagery were used to locate and assess the pit craters in addition to generated digital elevation models of the craters. Our results show that pitted craters have variable morphologies, where the pitted features could be oblique or linear in shape. Summit and floor pit craters were found in both maria and highland terrain. The Moran index and Chi statistical tests were applied and determined that the population is randomly distributed across the study area. Evaluation of the individual pit craters show that they may potentially have one or more formational mechanisms associated. The statistical tests coupled with the variant morphologies may indicate multiple relations to possible formational mechanisms (volcanic, volatile release, or structural deformation).

  3. Lunar Pit Craters Presumed to be the Entrances of Lava Caves by Analogy to the Earth Lava Tube Pits

    NASA Astrophysics Data System (ADS)

    Hong, Ik-Seon; Yi, Yu; Kim, Eojin

    2014-06-01

    Lava caves could be useful as outposts for the human exploration of the Moon. Lava caves or lava tubes are formed when the external surface of the lava flows cools more quickly to make a hardened crust over subsurface lava flows. The lava flow eventually ceases and drains out of the tube, leaving an empty space. The frail part of the ceiling of lava tube could collapse to expose the entrance to the lava tubes which is called a pit crater. Several pit craters with the diameter of around 100 meters have been found by analyzing the data of SELENE and LRO lunar missions. It is hard to use these pit craters for outposts since these are too large in scale. In this study, small scale pit craters which are fit for outposts have been investigated using the NAC image data of LROC. Several topographic patterns which are believed to be lunar caves have been found and the similar pit craters of the Earth were compared and analyzed to identify caves. For this analysis, the image data of satellites and aerial photographs are collected and classified to construct a database. Several pit craters analogous to lunar pit craters were derived and a morphological pit crater model was generated using the 3D printer based on this database.

  4. Method for Identifying Lava Tubes Among Pit Craters Using Brightness Profile Across Pits on the Moon or Mars

    NASA Astrophysics Data System (ADS)

    Jung, Jongil; Hong, Ik-Seon; Cho, Eunjin; Yi, Yu

    2016-03-01

    Caves can serve as major outposts for future human exploration of the Moon and Mars. In addition, caves can protect people and electronic equipment from external hazards such as cosmic ray radiation and meteorites impacts and serve as a shelter. Numerous pit craters have been discovered on the Moon and Mars and are potential entrances to caves; the principal topographic features of pit craters are their visible internal floors and pits with vertical walls. We have devised two topographical models for investigating the relationship between the topographical characteristics and the inner void of pit craters. One of our models is a concave floor void model and the other is a convex floor tube model. For each model, optical photographs have been obtained under conditions similar to those in which optical photographs have been acquired for craters on the Moon and Mars. Brightness profiles were analyzed for determining the profile patterns of the void pit craters. The profile patterns were compared to the brightness profiles of Martian pit craters, because no good-quality images of lunar pit craters were available. In future studies, the model profile patterns will be compared to those of lunar pit craters, and the proposed method will likely become useful for finding lunar caves and consequently for planning lunar bases for manned lunar expeditions.

  5. Evidence of stratabound liquefaction in the formation of fractured topographic margins, cone chains and pit catenas along the Martian Dichotomy Boundary and in Isidis Planitia, Mars.

    NASA Astrophysics Data System (ADS)

    Gallagher, C.; Balme, M. R.

    2012-04-01

    role in at least one mode of catena formation [2]. As well as presenting the morphological evidence for a genetic association between TPT and pit catenas, we present corroborative evidence that fluvial channel networks on Mars have in places increased in complexity through the linking of pits arranged in linear to arcuate arrays, culminating in a pseudo-branching channel network. Such systems do not occur at topographic margins and did not disintegrate into stepped crustal blocks. However, the scale of these channels and the volumes of liquid intermittently impounded in craters along these channel systems indicate that pit chains are associated with significant excess groundwater production leading to channelized flow, including catastrophic discharges when crater-impounded lakes along-flow were breached. Are the MDB and Isidis cone chains exhumed pit catenas and are the pits the surface expression of more deep-seated conduits? Do pit catenas indicate excess pore-water production, sufficient to link individual pits and dissect crustal blocks? Together, do these assemblages reflect the degradation of the MDB and Isidis margins and the subsequent stripping of adjacent low-lying plains? The crucial observations presented in this research (cone chains lying between crustal blocks, together with the morphometric similarities) are consistent with the interpretation of the cones and catenas having a common origin. Consequently, we hypothesise that the translated, back-rotated, tilted and capsized disposition of en echelon blocks is very reminiscent of the morphology produced during lateral spreading [3] associated with stratabound liquefaction below a low-gradient, rigid, insensitive surface. Significantly, such liquefaction events cause extensive, arcuate ground fractures along with the discharge of sediment-laden groundwater from the liquefiable substratum to the surface through pipes and conical boils confined within inter-block fractures. These conduits and their

  6. Bacillus vini sp. nov. isolated from alcohol fermentation pit mud.

    PubMed

    Ma, Kedong; Chen, Xiaorong; Guo, Xiang; Wang, Yanwei; Wang, Huimin; Zhou, Shan; Song, Jinlong; Kong, Delong; Zhu, Jie; Dong, Weiwei; He, Mingxiong; Hu, Guoquan; Zhao, Bingqiang; Ruan, Zhiyong

    2016-08-01

    A novel aerobic, Gram-stain-positive, sporogenous, rod-shaped bacterium, designated LAM0415(T), was isolated from an alcohol fermentation pit mud sample collected from Sichuan Luzhou-flavour liquor enterprise in China. The isolate was found to be able to grow at NaCl concentrations of 0-10 % (w/v) (optimum: 1.0 %), 10-50 °C (optimum: 30-35 °C) and pH 3.0-10.0 (optimum: 7.0-8.0). Phylogenetic analysis of 16S rRNA gene sequences indicated that the new isolate belonged to the genus Bacillus and was closely related to Bacillus sporothermodurans DSM 10599(T) and Bacillus oleronius DSM 9356(T), with 98.4 and 97.2 % sequence similarity, respectively. The DNA-DNA hybridization values between strain LAM0415(T) and the two reference strains were 33.3 ± 1.2 and 42.8 ± 0.8 %, respectively. The genomic DNA G+C content was 35.2 mol% as determined by the T m method. The major fatty acids were determined to be iso-C15:0, anteiso-C15:0 and anteiso-C17:0. The predominant menaquinones were identified as MK7 and MK8. The major polar lipids were found to be diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, one unidentified phospholipid and four unidentified glycolipids. The diagnostic amino acid of the cell wall peptidoglycan was determined to be meso-diaminopimelic acid. On the basis of its phenotypic, phylogenetic and chemotaxonomic characteristics, strain LAM0415(T) (=ACCC 06413(T) = JCM 19841(T)) represents the type strain of a novel species of the genus Bacillus, for which the name Bacillus vini sp. nov. is proposed. PMID:27055557

  7. USE OF ENVIRONMENTAL ISOTOPES TO DIFFERENTIATE WATER SOURCES AND CONSTRAIN THE WATER BUDGET AT THE SULPHUR BANK MERCURY MINE, CLEAR LAKE, CALIFORNIA

    EPA Science Inventory

    The Sulphur Bank Mercury Mine (SBMM) is a 65 ha site located on the eastern shore of the Oaks Arm of Clear Lake, Lake County, California. Between 1864 and 1957, SBMM was the site of underground and open pit mining operations for S and Hg, coinciding with past and present hot spr...

  8. The contribution of Fe(III) and humic acid reduction to ecosystem respiration in drained thaw lake basins of the Arctic Coastal Plain

    NASA Astrophysics Data System (ADS)

    Lipson, David A.; Raab, Theodore K.; Goria, Dominic; Zlamal, Jaime

    2013-04-01

    research showed that anaerobic respiration using iron (Fe) oxides as terminal electron acceptor contributed substantially to ecosystem respiration (ER) in a drained thaw lake basin (DTLB) on the Arctic coastal plain. As DTLBs age, the surface organic layer thickens, progressively burying the Fe-rich mineral layers. We therefore hypothesized that Fe(III) availability and Fe reduction would decline with basin age. We studied four DTLBs across an age gradient, comparing seasonal changes in the oxidation state of dissolved and extractable Fe pools and the estimated contribution of Fe reduction to ER. The organic layer thickness did not strictly increase with age for these four sites, though soil Fe levels decreased with increasing organic layer thickness. However, there were surprisingly high levels of Fe minerals in organic layers, especially in the ancient basin where cryoturbation may have transported Fe upward through the profile. Net reduction of Fe oxides occurred in the latter half of the summer and contributed an estimated 40-45% to ecosystem respiration in the sites with the thickest organic layers and 61-63% in the sites with the thinnest organic layers. All sites had high concentrations of soluble Fe(II) and Fe(III), explained by the presence of siderophores, and this pool became progressively more reduced during the first half of the summer. Redox titrations with humic acid (HA) extracts and chelated Fe support our view that this pattern indicates the reduction of HA during this interval. We conclude that Fe(III) and HA reductions contribute broadly to ER in the Arctic coastal plain.

  9. Variation of physicochemical properties of drinking water treatment residuals and Phoslock(®) induced by fulvic acid adsorption: Implication for lake restoration.

    PubMed

    Wang, Changhui; Jiang, He-Long; Xu, Huacheng; Yin, Hongbin

    2016-01-01

    The use of phosphorus (P) inactivating agents to reduce internal P loading from sediment for lake restoration has attracted increasing attention. Reasonably, the physicochemical properties of P inactivating agents may vary with the interference of various environmental factors, leading to the change of control effectiveness and risks. In this study, the effect of fulvic acid (FA) adsorption on the properties of two agents, drinking water treatment residuals (DWTRs) and Phoslock®, was investigated. The results showed that after adsorption, there was little change for the main structures of DWTRs and Phoslock®, but the thermostability of Phoslock®, as well as the particle size and settleability of the two agents decreased. The specific surface area and pore volume of DWTRs also decreased, while those of Phoslock® increased. Further analysis indicated that aluminum and iron in DWTRs were stable during FA adsorption, but a substantial increase of lanthanum release from Phoslock® was observed, in particular at first (P < 0.01). Moreover, the P immobilization capability of DWTRs had little change after FA adsorption, while the capability of Phoslock® after FA adsorption decreased in solutions (P < 0.001) and sediments (P < 0.1); interestingly, from the view of engineering application, the performance of Phoslock® was not substantially affected. Overall, each P inactivating agent had its own particular responses of the physicochemical properties to environment factors, and detailed investigations on the applicability of each agent were essential before practical application.

  10. Improving inferences from fisheries capture-recapture studies through remote detection of PIT tags

    USGS Publications Warehouse

    Hewitt, David A.; Janney, Eric C.; Hayes, Brian S.; Shively, Rip S.

    2010-01-01

    Models for capture-recapture data are commonly used in analyses of the dynamics of fish and wildlife populations, especially for estimating vital parameters such as survival. Capture-recapture methods provide more reliable inferences than other methods commonly used in fisheries studies. However, for rare or elusive fish species, parameter estimation is often hampered by small probabilities of re-encountering tagged fish when encounters are obtained through traditional sampling methods. We present a case study that demonstrates how remote antennas for passive integrated transponder (PIT) tags can increase encounter probabilities and the precision of survival estimates from capture-recapture models. Between 1999 and 2007, trammel nets were used to capture and tag over 8,400 endangered adult Lost River suckers (Deltistes luxatus) during the spawning season in Upper Klamath Lake, Oregon. Despite intensive sampling at relatively discrete spawning areas, encounter probabilities from Cormack-Jolly-Seber models were consistently low (< 0.2) and the precision of apparent annual survival estimates was poor. Beginning in 2005, remote PIT tag antennas were deployed at known spawning locations to increase the probability of re-encountering tagged fish. We compare results based only on physical recaptures with results based on both physical recaptures and remote detections to demonstrate the substantial improvement in estimates of encounter probabilities (approaching 100%) and apparent annual survival provided by the remote detections. The richer encounter histories provided robust inferences about the dynamics of annual survival and have made it possible to explore more realistic models and hypotheses about factors affecting the conservation and recovery of this endangered species. Recent advances in technology related to PIT tags have paved the way for creative implementation of large-scale tagging studies in systems where they were previously considered impracticable.

  11. Hydrologic analysis of two headwater lake basins of differing lake pH in the west-central Adirondack Mountains of New York

    USGS Publications Warehouse

    Murdoch, Peter S.; Peters, N.E.; Newton, R.M.

    1987-01-01

    Hydrologic analysis of two headwater lake basins in the Adirondack Mountains, New York, during 1980-81 indicates that the degree of neutralization of acid precipitation is controlled by the groundwater contribution to the lake. According to flow-duration analyses, daily mean outflow/unit area from the neutral lake (Panther Lake, pH 5-7) was more sustained and contained a higher percentage of groundwater than that of the acidic lake (Woods Lake, pH 4-5). Outflow recession rates and maximum base-flow rates, derived from individual recession curves, were 3.9 times and 1.5 times greater, respectively, in the neutral-lake basin than in the acidic-lake basin. Groundwater contribution to lake outflow was also calculated from a lake-water budget; the groundwater contribution to the neutral lake was about 10 times greater than that to the acidic lake. Thick sandy till forms the groundwater reservoir and the major recharge area in both basins but covers 8.5 times more area in the neutral-lake basin than in the acidic-lake basin. More groundwater storage within the neutral basin provides longer contact time with neutralizing minerals and more groundwater discharge. As a result, the neutral lake has relatively high pH and alkalinity, and more net cation transport. (USGS)

  12. Principles of lake sedimentology

    SciTech Connect

    Janasson, L.

    1983-01-01

    This book presents a comprehensive outline on the basic sedimentological principles for lakes, and focuses on environmental aspects and matters related to lake management and control-on lake ecology rather than lake geology. This is a guide for those who plan, perform and evaluate lake sedimentological investigations. Contents abridged: Lake types and sediment types. Sedimentation in lakes and water dynamics. Lake bottom dynamics. Sediment dynamics and sediment age. Sediments in aquatic pollution control programmes. Subject index.

  13. Forest blowdown and lake acidification

    SciTech Connect

    Dobson, J.E.; Rush, R.M. ); Peplies, R.W. )

    1990-01-01

    The authors examine the role of forest blowdown in lake acidification. The approach combines geographic information systems (GIS) and digital remote sensing with traditional field methods. The methods of analysis consist of direct observation, interpretation of satellite imagery and aerial photographs, and statistical comparison of two geographical distributions-one representing forest blow-down and another representing lake chemistry. Spatial and temporal associations between surface water pH and landscape disturbance are strong and consistent in the Adirondack Mountains of New York. In 43 Adirondack Mountain watersheds, lake pH is associated with the percentage of the watershed area blown down and with hydrogen ion deposition (Spearman rank correlation coefficients of {minus}0.67 and {minus}0.73, respectively). Evidence of a temporal association is found at Big Moose Lake and Jerseyfield Lake in New York and the Lygners Vider Plateau of Sweden. They conclude that forest blowdown facilities the acidification of some lakes by altering hydrologic pathways so that waters (previously acidified by acid deposition and/or other sources) do not experience the neutralization normally available through contact with subsurface soils and bedrock. Increased pipeflow is suggested as a mechanism that may link the biogeochemical impacts of forest blowdown to lake chemistry.

  14. Investigating oiled birds from oil field waste pits

    SciTech Connect

    Gregory, D.G.; Edwards, W.C. )

    1991-10-01

    Procedures and results of investigations concerning the oiling of inland raptors, migratory water-fowl and other birds are presented. Freon washings from the oiled birds and oil from the pits were analyzed by gas chromatography. In most instances the source of the oil could be established by chromatographic procedures. The numbers of birds involved (including many on the endangered species list) suggested the need for netting or closing oil field waste pits and mud disposal pits. Maintaining a proper chain of custody was important.

  15. Ability of Pit and Fissure Sealant-containing Amorphous Calcium Phosphate to inhibit Enamel Demineralization

    PubMed Central

    Owais, Arwa I; Kawaja, Wasan

    2016-01-01

    ABSTRACT Aim: To evaluate the effect of amorphous calcium phosphate (ACP)-containing pit and fissure sealant on inhibition of enamel demineralization in vitro. Materials and methods: Enamel specimens (n = 75) were prepared using freshly extracted noncarious human third molars. Box-shaped cavities (8 × 2 × 2 mm) on the buccal or lingual surfaces were prepared and restored with resin-based sealant (Concise™), ACP-containing sealant (Aegis®) or fluoride-containing sealant (Conseal-F™). The samples were acid challenged in a demineralizing solution of 50 mmol/l lactic acid at pH 5.0 for 4 days. The change in enamel microhardness (ASuH) was calculated. Data were analyzed using one-way analysis of variance (ANOVA) and Tukey’s post hoc test. Results: The mean SuH0 (±SD) (in Vicker’s unit) prior to the acid challenge was: Concise™ (318.83 ± 33.86), Aegis® (331.03 ± 21.52), Conseal-F™ (310.12 ± 34.31). Following the acid challenge, the values dropped in all groups and ASuH (±SD) values were 269.17 ± 47.49, 151.39 ± 23.96 and 175.79 ± 32.39 respectively. Conclusion: The ACP-containing pit and fissure sealant has the potential to inhibit enamel demineralization. How to cite this article: Zawaideh FI, Owais AI, Kawaja W. Ability of pit and fissure sealant-containing amorphous calcium phosphate to inhibit enamel demineralization. Int J Clin Pediatr Dent 2016;9(1):10-14. PMID:27274148

  16. Lake restoration technology transfer assessment

    SciTech Connect

    Daschbach, M.H.; Roe, E.M.; Sharpe, W.E.

    1982-06-01

    Based upon a review of the eutrophication problem and its impact on lake restoration (LR) programs, treatment of the relatively new problem of acid deposition and its impact on LR activities, consideration of the LR programs of the Environmental Protection Agency and several states, and a review of individual LR technology transfer publications, it is recommended that new LR technology transfer programs be given a low priority until more new information is available on the restoration of acidified lakes. Both primary and secondary users of LR research, technology transfer documents, and public awareness documents were considered in this assessment. Primary users included the general public and recreationists, lakeshore property owners, lake/homeowner associations, lake/sanitary districts, and research and environmental organizations; secondary users included state/county/local officials who administer/manage water-related regulations/activities. 4 tables.

  17. The effects of a dredge excavation pit on benthic macrofauna in offshore Louisiana.

    PubMed

    Palmer, Terence A; Montagna, Paul A; Nairn, Robert B

    2008-04-01

    Over two years after the original creation of a sand excavation pit 8 km off the Louisiana coast, benthic macrofauna communities and sedimentary characteristics are still effected. Macrofaunal communities inside the pit had lower abundance, biomass, and diversity than communities outside the pit. This difference, however, was only significant with some of the stations outside the pit. Results from multi-dimensional scaling and cluster analysis showed that macrofaunal communities were less than 32% similar inside the pit to communities outside the pit. The polychaete Mediomastus ambiseta was the most abundant species outside the excavation pit, but the species was only counted once inside the pit. The most dominant species, which made up over 90% of organisms inside the pit, was the pioneer polychaete Paraprionospio pinnata. Only three species were found at each station inside the pit as opposed to 9-27 species at stations outside the pit. All species inside the pit were also found outside the pit; thus, change was due to a loss of species rather than replacement by different species. Sediment inside the pit contained more silt and clay; however, no difference in water quality was detected compared with outside the pit. Hurricanes Katrina and Rita passed near the dredge pit in 2005 and could have effected sediment transport in the region. Because the macrofaunal community inside the pit has not recovered within 38 months, it is likely that it will require more time before it resembles the surrounding conditions.

  18. The Effects of a Dredge Excavation Pit on Benthic Macrofauna in Offshore Louisiana

    NASA Astrophysics Data System (ADS)

    Palmer, Terence A.; Montagna, Paul A.; Nairn, Robert B.

    2008-04-01

    Over two years after the original creation of a sand excavation pit 8 km off the Louisiana coast, benthic macrofauna communities and sedimentary characteristics are still effected. Macrofaunal communities inside the pit had lower abundance, biomass, and diversity than communities outside the pit. This difference, however, was only significant with some of the stations outside the pit. Results from multi-dimensional scaling and cluster analysis showed that macrofaunal communities were less than 32% similar inside the pit to communities outside the pit. The polychaete Mediomastus ambiseta was the most abundant species outside the excavation pit, but the species was only counted once inside the pit. The most dominant species, which made up over 90% of organisms inside the pit, was the pioneer polychaete Paraprionospio pinnata. Only three species were found at each station inside the pit as opposed to 9-27 species at stations outside the pit. All species inside the pit were also found outside the pit; thus, change was due to a loss of species rather than replacement by different species. Sediment inside the pit contained more silt and clay; however, no difference in water quality was detected compared with outside the pit. Hurricanes Katrina and Rita passed near the dredge pit in 2005 and could have effected sediment transport in the region. Because the macrofaunal community inside the pit has not recovered within 38 months, it is likely that it will require more time before it resembles the surrounding conditions.

  19. Retaining latch for a water pit gate

    DOEpatents

    Beale, Arden R.

    1997-01-01

    A retaining latch for use in a hazardous materials storage or handling facility to adjustably retain a water pit gate in a gate frame. A retaining latch is provided comprising a latch plate which is rotatably mounted to each end of the top of the gate and a recessed opening, formed in the gate frame, for engaging an edge of the latch plate. The latch plate is circular in profile with one side cut away or flat, such that the latch plate is D-shaped. The remaining circular edge of the latch plate comprises steps of successively reduced thickness. The stepped edge of the latch plate fits inside a recessed opening formed in the gate frame. As the latch plate is rotated, alternate steps of the latch plate are engaged by the recessed opening. When the latch plate is rotated such that the flat portion of the latch plate faces the recessed opening in the gate frame, there is no connection between the opening and the latch plate and the gate is unlatched from the gate frame.

  20. Retaining latch for a water pit gate

    DOEpatents

    Beale, A.R.

    1997-11-18

    A retaining latch is described for use in a hazardous materials storage or handling facility to adjustably retain a water pit gate in a gate frame. A retaining latch is provided comprising a latch plate which is rotatably mounted to each end of the top of the gate and a recessed opening, formed in the gate frame, for engaging an edge of the latch plate. The latch plate is circular in profile with one side cut away or flat, such that the latch plate is D-shaped. The remaining circular edge of the latch plate comprises steps of successively reduced thickness. The stepped edge of the latch plate fits inside a recessed opening formed in the gate frame. As the latch plate is rotated, alternate steps of the latch plate are engaged by the recessed opening. When the latch plate is rotated such that the flat portion of the latch plate faces the recessed opening in the gate frame, there is no connection between the opening and the latch plate and the gate is unlatched from the gate frame. 4 figs.

  1. Lake Powell

    NASA Technical Reports Server (NTRS)

    2007-01-01

    The white ring around Lake Powell tells the story. The surface is down 98 feet. This is critical, because Powell, Lake Mead, and other lakes along the Colorado River provide water for millions of people in five states. We are in the eighth year of a drought on the Colorado River. This year was the driest year ever reported in Southern California, and there is a severe drought in Northern California, down to less than 30-percent of snow pack. This ASTER image of part of Lake Powell was acquired in 2001. The gray area depicts the shrunken, reduced 2007 lake extent compared to the extended, larger black area in 2001.

    The image covers an area of 24 x 30 km, and is centered near 37.1 degrees north latitude, 111.3 degrees west longitude.

    The U.S. science team is located at NASA's Jet Propulsion Laboratory, Pasadena, Calif. The Terra mission is part of NASA's Science Mission Directorate.

  2. Natural killer (NK) activity of pit cells perfused from livers of rats treated with ethanol

    SciTech Connect

    Albornoz, L.; Jones, J.M.; Crutchfield, C.; Veech, R.L. Univ. of Arkansas Medical Sciences, Little Rock )

    1991-03-11

    The liver is the major site of ethanol (ETOH) metabolism. Liver sinusoids contain lymphocytes with NK activity. The authors treated LEW rats for 2 weeks with i.p. injection of 1.25 ml 25% ETOH/kg 3 times/week and 5% ETOH in drinking water. Livers were perfused at 5-fold physiological pressure and cells obtained were banded on 1.077 density Ficoll. Their cytotoxicity was tested against {sup 51}Cr-labeled YAC-1 or U937 and compared to spleen and blood lymphocytes. In untreated rats, pit cell NK activity was 2-fold that of splenic lymphocytes and 4-fold that of blood lymphocytes. Compared to controls, ETOH-treated rats exhibited a 30 to 90% rise in pit cell NK activity detected with YAC-1 or U937 targets. The pit cell enhanced NK activity in ETOH-treated rats was further increased if polyinosinicpolycytidilic acid was injection i.p. 18 hours before the assay. Blood and spleen lymphocyte NK activity of ETOH-treated rats was also greater than in controls. There was no evidence that ETOH merely redistributed lymphocytes among the tissues. Although ETOH acutely inhibits NK activity in vitro, chronic ETOH increases in vivo.

  3. Acid rain

    SciTech Connect

    Not Available

    1985-01-01

    This report has four parts: they discuss acid rain in relation to acid soils, agriculture, forests, and aquatic ecosystems. Among findings: modern sources of acid deposition from the atmosphere for all the acid soils in the world, nor even chiefly responsible for those of northern U.S. Agriculture has its problems, but acid precipitation is probably not one of them. More research is needed to determine to what extent acid precipitation is responsible for forest declines and for smaller detrimental effects on forest growth where no damage to the foliage is evident. Many lakes and streams are extremely sensitive to added acids.

  4. Mirror Lake: Past, present and future: Chapter 6

    USGS Publications Warehouse

    Likens, Gene E.; LaBaugh, James W.; Winter, Thomas C.; Likens, Gene E.

    2009-01-01

    This chapter discusses the hydrological and biogeochemical characteristics of Mirror Lake and the changes that resulted from air-land-water interactions and human activities. Since the formation of Mirror Lake, both the watershed and the lake have undergone many changes, such as vegetation development and basin filling. These changes are ongoing, and Mirror Lake is continuing along an aging pathway and ultimately, it will fill with sediment and no longer be a lake. The chapter also identifies major factors that affected the hydrology and biogeochemistry of Mirror Lake: acid rain, atmospheric deposition of lead and other heavy metals, increased human settlement around the lake, the construction of an interstate highway through the watershed of the Northeast Tributary, the construction of an access road through the West and Northeast watersheds to the lake, and climate change. The chapter also offers future recommendations for management and protection of Mirror Lake.

  5. 15. INTERIOR, INSPECTION PITS, OVERHEAD CATWALKS AND OVERHEAD CRANE SUPPORT, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    15. INTERIOR, INSPECTION PITS, OVERHEAD CATWALKS AND OVERHEAD CRANE SUPPORT, FACING WEST - Delaware, Lackawanna & Western Railroad Freight & Rail Yard, Multiple Unit Light Inspection Shed, New Jersey Transit Hoboken Terminal Rail Yard, Hoboken, Hudson County, NJ

  6. 14. INTERIOR, INSPECTION PITS AND OVERHEAD CATWALKS, FACING WEST ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    14. INTERIOR, INSPECTION PITS AND OVERHEAD CATWALKS, FACING WEST - Delaware, Lackawanna & Western Railroad Freight & Rail Yard, Multiple Unit Light Inspection Shed, New Jersey Transit Hoboken Terminal Rail Yard, Hoboken, Hudson County, NJ

  7. 17. INTERIOR, INSPECTION PITS, OVERHEAD CRANE SUPPORT AND CAR JACKING ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    17. INTERIOR, INSPECTION PITS, OVERHEAD CRANE SUPPORT AND CAR JACKING PADS, FACING EAST - Delaware, Lackawanna & Western Railroad Freight & Rail Yard, Multiple Unit Light Inspection Shed, New Jersey Transit Hoboken Terminal Rail Yard, Hoboken, Hudson County, NJ

  8. 18. LOOKING EAST AT THE HOT METAL RELADLING PIT No. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    18. LOOKING EAST AT THE HOT METAL RELADLING PIT No. 1 ON THE CHARGING AISLE OF THE BOP SHOP. - U.S. Steel Duquesne Works, Basic Oxygen Steelmaking Plant, Along Monongahela River, Duquesne, Allegheny County, PA

  9. 24. SOUTHEAST VIEW OF LADLE REPAIR PIT ON THE WESTERN ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    24. SOUTHEAST VIEW OF LADLE REPAIR PIT ON THE WESTERN TEEMING AISLE OF THE BOP SHOP. LOOKING SOUTHEAST. - U.S. Steel Duquesne Works, Basic Oxygen Steelmaking Plant, Along Monongahela River, Duquesne, Allegheny County, PA

  10. CONSTRUCTION PROGRESS PHOTO SHOWING EXCAVATION PIT FOR MAIN PROCESSING BUILDING ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    CONSTRUCTION PROGRESS PHOTO SHOWING EXCAVATION PIT FOR MAIN PROCESSING BUILDING (CPP-601) LOOKING SOUTH. INL PHOTO NUMBER NRTS-50-693. Unknown Photographer, 1950 - Idaho National Engineering Laboratory, Idaho Chemical Processing Plant, Fuel Reprocessing Complex, Scoville, Butte County, ID

  11. Molten salt corrosion of SiC: Pitting mechanism

    NASA Technical Reports Server (NTRS)

    Jacobson, N. S.; Smialek, J. L.

    1985-01-01

    Thin films of Na2SO4 and Na2CO3 at 1000 C lead to severe pitting of sintered alpha-SiC. These pits are important as they cause a strength reduction in this material. The growth of product layers is related to pit formation for the Na2CO3 case. The early reaction stages involve repeated oxidation and dissolution to form sodium silicate. This results in severe grain boundary attack. After this a porous silica layer forms between the sodium silicate melt and the SiC. The pores in this layer appear to act as paths for the melt to reach the SiC and create larger pits.

  12. 105-KW Sandfilter Backwash Pit sludge volume calculation

    SciTech Connect

    Dodd, E.N. Jr.

    1995-02-10

    The volume of sludge contained in the 100-KW Sandfilter Backwash Pit (SFBWP) was calculated from depth measurements of the sludge, pit dimension measurements and analysis of video tape recordings taken by an underwater camera. The term sludge as used in this report is any combination of sand, sediment, or corrosion products visible in the SFBWP area. This work was performed to determine baseline volume for use in determination of quantities of uranium and plutonium deposited in the pit from sandfilter backwashes. The SFBWP has three areas where sludge is deposited: (1) the main pit floor, (2) the transfer channel floor, and (3) the surfaces and structures in the SFBWP. The depths of sludge and the uniformity of deposition varies significantly between these three areas. As a result, each of the areas was evaluated separately. The total volume of sludge determined was 3.75 M{sup 3} (132.2 ft{sup 3}).

  13. 23. Closer perspective view from the southwest. An archaeological pit ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    23. Closer perspective view from the southwest. An archaeological pit is located under the center first-floor window. - John Bartram House & Garden, House, 54th Street & Lindbergh Boulevard, Philadelphia, Philadelphia County, PA

  14. 22. VIEW SOUTH, INTERIOR OF SOUTH PIT, SHOWING FINAL STEP ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    22. VIEW SOUTH, INTERIOR OF SOUTH PIT, SHOWING FINAL STEP IN GEARING THAT DRIVES OPERATING WHEEL, WITH HYDRAULIC SHAFT BRAKE - Mystic River Bridge, Spanning Mystic River at U.S. Route 1, Groton, New London County, CT

  15. Pit latrine effluent infiltration into groundwater: the Epworth case study.

    PubMed

    Chidavaenzi, M; Bradley, M; Jere, M; Nhandara, C

    2000-01-01

    Water can be a vehicle for the transmission of communicable diseases. Technologies have been developed to protect groundwater from external surface contamination. However, there is growing concern about the likelihood of pit latrine effluent infiltrating into groundwater reservoirs for well water supply systems. Investigations on seasonal variations and extent of pit latrine effluent infiltration into soil and groundwater have been carried out in Zimbabwe. Preliminary results show that groundwater flows in the direction of surface runoff, and that there is no lateral soil pollution above the groundwater surface. Pit latrine contents leach downwards and down slopes for distances that vary per season and soil type. The results also demonstrate the contribution of refuse pits and water collection methods to groundwater pollution.

  16. BARBEQUE PIT AND PLAYHOUSE IN (REAR) YARD, LOOKING SOUTH ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    BARBEQUE PIT AND PLAYHOUSE IN (REAR) YARD, LOOKING SOUTH - Irvine Ranch Agricultural Headquarters, Carillo Tenant House, Southwest of Intersection of San Diego & Santa Ana Freeways, Irvine, Orange County, CA

  17. CHICKEN COOP BEHIND FENCED YARD AND (REAR) OF BARBEQUE PIT, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    CHICKEN COOP BEHIND FENCED YARD AND (REAR) OF BARBEQUE PIT, LOOKING NORTH - Irvine Ranch Agricultural Headquarters, Carillo Tenant House, Southwest of Intersection of San Diego & Santa Ana Freeways, Irvine, Orange County, CA

  18. 13. VIEW OF BARBECUE PIT, FACING EAST. (BUILDING 132 IS ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    13. VIEW OF BARBECUE PIT, FACING EAST. (BUILDING 132 IS IN BACKGROUND ON RIGHT.) - Fort McPherson, World War II Station Hospital, Structures, Bordered by Hardee & Thorne Avenues & Howe Street, Atlanta, Fulton County, GA

  19. Pitting of stainless steel in an emergency service water system

    SciTech Connect

    Morgan, D.J.; Willertz, L.E.

    1994-12-31

    Pitting of AISI 321 grade stainless steel flex-hoses in an emergency service water system has been experienced recently, after 13 years of successful service. Failures of new hoses have occurred in as little as 4 months. This paper presents the authors analysis of the failures and discusses the primary suspected mechanisms, underdeposit pitting and microbiologically influenced corrosion (MIC). It also presents their approach for investigating suspected causes and developing an integrated plan to minimize its recurrence.

  20. Ion induced changes in the structure of bordered pit membranes.

    PubMed

    Lee, Jinkee; Holbrook, N Michele; Zwieniecki, Maciej A

    2012-01-01

    Ion-mediated changes in xylem hydraulic resistance are hypothesized to result from hydrogel like properties of pectins located in the bordered pit membranes separating adjacent xylem vessels. Although the kinetics of the ion-mediated changes in hydraulic resistance are consistent with the swelling/deswelling behavior of pectins, there is no direct evidence of this activity. In this report we use atomic force microscopy (AFM) to investigate structural changes in bordered pit membranes associated with changes in the ionic concentration of the surrounding solution. When submerged in de-ionized water, AFM revealed bordered pit membranes as relatively smooth, soft, and lacking any sharp edges surface, in contrast to pictures from scanning electron microscope (SEM) or AFM performed on air-dry material. Exposure of the bordered pit membranes to 50 mM KCl solution resulted in significant changes in both surface physical properties and elevation features. Specifically, bordered pit membranes became harder and the fiber edges were clearly visible. In addition, the membrane contracted and appeared much rougher due to exposed microfibers. In neither solution was there any evidence of discrete pores through the membrane whose dimensions were altered in response to the ionic composition of the surrounding solution. Instead the variable hydraulic resistance appears to involve changes in the both the permeability and the thickness of the pit membrane.

  1. Corrosion pitting and environmentally assisted small crack growth

    PubMed Central

    Turnbull, Alan

    2014-01-01

    In many applications, corrosion pits act as precursors to cracking, but qualitative and quantitative prediction of damage evolution has been hampered by lack of insights into the process by which a crack develops from a pit. An overview is given of recent breakthroughs in characterization and understanding of the pit-to-crack transition using advanced three-dimensional imaging techniques such as X-ray computed tomography and focused ion beam machining with scanning electron microscopy. These techniques provided novel insights with respect to the location of crack development from a pit, supported by finite-element analysis. This inspired a new concept for the role of pitting in stress corrosion cracking based on the growing pit inducing local dynamic plastic strain, a critical factor in the development of stress corrosion cracks. Challenges in quantifying the subsequent growth rate of the emerging small cracks are then outlined with the potential drop technique being the most viable. A comparison is made with the growth rate for short cracks (through-thickness crack in fracture mechanics specimen) and long cracks and an electrochemical crack size effect invoked to rationalize the data. PMID:25197249

  2. Corrosion pitting and environmentally assisted small crack growth.

    PubMed

    Turnbull, Alan

    2014-09-01

    In many applications, corrosion pits act as precursors to cracking, but qualitative and quantitative prediction of damage evolution has been hampered by lack of insights into the process by which a crack develops from a pit. An overview is given of recent breakthroughs in characterization and understanding of the pit-to-crack transition using advanced three-dimensional imaging techniques such as X-ray computed tomography and focused ion beam machining with scanning electron microscopy. These techniques provided novel insights with respect to the location of crack development from a pit, supported by finite-element analysis. This inspired a new concept for the role of pitting in stress corrosion cracking based on the growing pit inducing local dynamic plastic strain, a critical factor in the development of stress corrosion cracks. Challenges in quantifying the subsequent growth rate of the emerging small cracks are then outlined with the potential drop technique being the most viable. A comparison is made with the growth rate for short cracks (through-thickness crack in fracture mechanics specimen) and long cracks and an electrochemical crack size effect invoked to rationalize the data. PMID:25197249

  3. PIT tags increase effectiveness of freshwater mussel recaptures

    USGS Publications Warehouse

    Kurth, J.; Loftin, C.; Zydlewski, J.; Rhymer, J.

    2007-01-01

    Translocations are used increasingly to conserve populations of rare freshwater mussels. Recovery of translocated mussels is essential to accurate assessment of translocation success. We designed an experiment to evaluate the use of passive integrated transponder (PIT) tags to mark and track individual freshwater mussels. We used eastern lampmussels (Lampsilis radiata radiata) as a surrogate for 2 rare mussel species. We assessed internal and external PIT-tag retention in the laboratory and field. Internal tag retention was high (75-100%), and tag rejection occurred primarily during the first 3 wk after tagging. A thin layer of nacre coated internal tags 3 to 4 mo after insertion, suggesting that long-term retention is likely. We released mussels with external PIT tags at 3 field study sites and recaptured them with a PIT pack (mobile interrogation unit) 8 to 10 mo and 21 to 23 mo after release. Numbers of recaptured mussels differed among study sites; however, we found more tagged mussels with the PIT-pack searches with visual confirmation (72-80%) than with visual searches alone (30-47%) at all sites. PIT tags offer improved recapture of translocated mussels and increased accuracy of posttranslocation monitoring. ?? 2007 by The North American Benthological Society.

  4. Role of chicken Pit-1 isoforms in activating growth hormone gene.

    PubMed

    Murase, Daisuke; Taniuchi, Shusuke; Takeuchi, Sakae; Adachi, Hiromi; Kansaku, Norio; Okazaki, Katsuichiro; Ohkubo, Takeshi

    2011-09-01

    In the present study, we expressed chicken (ch) Pit-1α (chPit-1α) and chPit-1γin vitro to compare the roles of chPit-1s in the transcription of the chicken growth hormone (chGH) gene. Both green fluorescence protein (GFP)-fused chPit-1γ and GFP-fused chPit-1α were localized in the nuclei of COS-7 cells. In a luciferase reporter gene assay, both chPit-1α and chPit-1γ transactivated the chGH promoter, and chPit-1α showed a more potent effect than chPit-1γ. On the other hand, an increase of cellular cAMP induced by forskolin promoted transactivation of the chGH gene with chPit-1α and chPit-1γ to similar extents. These results suggest that chPit-1γ may modulate the basal promoter activity of the chGH gene to the same degree as chPit-1α; however, a structural difference observed at the N-terminus transactivation domains in chPit-1α and chPit-1γ could be associated with the efficiency of basal activation of the chGH promoter. PMID:21703269

  5. 7 CFR 52.802 - Grades of frozen red tart pitted cherries.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 2 2013-01-01 2013-01-01 false Grades of frozen red tart pitted cherries. 52.802... of Frozen Red Tart Pitted Cherries Product Description and Grades § 52.802 Grades of frozen red tart pitted cherries. (a) “U.S. Grade A” (or “U.S. Fancy”) is the quality of frozen red tart pitted...

  6. 7 CFR 52.802 - Grades of frozen red tart pitted cherries.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 2 2014-01-01 2014-01-01 false Grades of frozen red tart pitted cherries. 52.802... of Frozen Red Tart Pitted Cherries Product Description and Grades § 52.802 Grades of frozen red tart pitted cherries. (a) “U.S. Grade A” (or “U.S. Fancy”) is the quality of frozen red tart pitted...

  7. One dimensional Linescan x-ray detection of pits in fresh cherries

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The presence of pits in processed cherries is a concern for both processors and consumers, in many cases causing injury and potential lawsuits. While machines used for pitting cherries are extremely efficient, if one or more plungers in a pitting head become misaligned, a large number of pits may p...

  8. Real-time methods for non-destructive detection of pits in fresh cherries

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The presence of pits in processed cherries is a concern for both processors and consumers, in many cases causing injury and potential lawsuits. While machines used for pitting cherries are extremely efficient, if one or more plungers in a pitting head become misaligned, a large number of pits may p...

  9. Tissue-specific distribution of fatty acids, polychlorinated biphenyls and polybrominated diphenyl ethers in fish from Taihu Lake, China, and the benefit-risk assessment of their co-ingestion.

    PubMed

    Zhang, Dong-Ping; Zhang, Xin-Yu; Yu, Ying-Xin; Li, Jun-Ling; Yu, Zhi-Qiang; Wu, Ming-Hong; Fu, Jia-Mo

    2012-08-01

    The fish tissues from four species collected from Taihu Lake, China, were analyzed including dorsal, ventral, and tail muscles, heart, liver, and kidney. The highest and lowest concentrations of fatty acids were respectively observed in livers and muscles. There were significant intraspecies and interspecies differences in the compositions of most fatty acids among muscle, heart, liver, and kidney. All the tissues were generally beneficial for consumption considering fatty acids. People mainly consume the muscle. Hence, the benefits from two polyunsaturated fatty acids, i.e., eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), and risks from PCBs and PBDEs via fish consumption were evaluated by calculating the benefit-risk quotient (BFQ) for the intake of fish muscle containing EPA+DHA vs. PCBs or PBDEs. The BFQ values considering carcinogenic and noncarcinogenic effects for PCBs were ∼3000 and 10 times higher than those of PBDEs via fish consumption to achieve the recommended EPA+DHA intake of 250 mg d(-1), respectively. The results also suggested that the risk consuming the dorsal muscle was generally lower than the ventral and tail muscles. PMID:22664422

  10. Morphological variation of siscowet lake trout in Lake Superior

    USGS Publications Warehouse

    Bronte, C.R.; Moore, S.A.

    2007-01-01

    Historically, Lake Superior has contained many morphologically distinct forms of the lake trout Salvelinus namaycush that have occupied specific depths and locations and spawned at specific times of the year. Today, as was probably the case historically, the siscowet morphotype is the most abundant. Recent interest in harvesting siscowets to extract oil containing omega-3 fatty acids will require additional knowledge of the biology and stock structure of these lightly exploited populations. The objective of this study was to determine whether shape differences exist among siscowet populations across Lake Superior and whether these shape differences can be used to infer stock structure. Morphometric analysis (truss protocol) was used to differentiate among siscowets sampled from 23 locations in Lake Superior. We analyzed 31 distance measurements among 14 anatomical landmarks taken from digital images of fish recorded in the field. Cluster analysis of size-corrected data separated fish into three geographic groups: The Isle Royale, eastern (Michigan), and western regions (Michigan). Finer scales of stock structure were also suggested. Discriminant function analysis demonstrated that head measurements contributed to most of the observed variation. Cross-validation classification rates indicated that 67–71% of individual fish were correctly classified to their region of capture. This is the first study to present shape differences associated with location within a lake trout morphotype in Lake Superior.

  11. Addition of fluoride to pit and fissure sealants--a feasibility study.

    PubMed

    Swartz, M L; Phillips, R W; Norman, R D; Elliason, S; Rhodes, B F; Clark, H E

    1976-01-01

    The data obtained in this in vitro study indicate that contact with pit and fissure sealants to which NaF has been added in amounts ranging from 2 to 5% substantially increases the fluoride content of the enamel and reduces its solubility in acid. The properties of the materials do not seem to be impaired by the addition of fluoride in these amounts. It thus appears that this approach to providing a backup anticariogenic mechanism may, indeed, be feasible. However, further investigation must be done to confirm the anticariogenic effect and to establish the most efficacious means of fluoride incorporation in the materials.

  12. Water quality of selected lakes in Mount Rainier National Park, Washington with respect to lake acidification

    USGS Publications Warehouse

    Turney, G.L.; Dion, N.P.; Sumioka, S.S.

    1986-01-01

    Thirteen lakes in Mount Rainier National Park were evaluated for general chemical characteristics, sensitivity to acidification by acidic precipitation, and degree of existing acidification. The lakes studies were Allen, one of the Chenuis group, Crescent , Crystal, Eleanor, Fan, one of the Golden group, Marsh, Mowich, Mystic, Shriner, and two unnamed lakes. The lakes were sampled in August 1983. Specific conductance values were generally 21 microsiemens/cm at 25 C or less, and dissolved solids concentrations were generally 20 mg/L or less. The major cations were calcium and sodium, and the major anion was bicarbonate. Alkalinity concentrations ranged from 2.1 to 9.0 mg/L in 12 of the lakes. Allen Lake was the exception, having an alkalinity concentration of 27 mg/L. The pH values for all of the lakes ranged from 5.8 to 6.5. In most of the lakes, vertical profiles of temperature, dissolved oxygen, pH, and specific conductance were relatively uniform. In the deeper lakes, temperature decreased with depth and dissolved-oxygen concentrations increased to about 20 feet, remained constant to 80 ft, then decreased with increasing depth. Exceptions to general water quality patterns were observed in three lakes. Allen Lake had a specific conductance value of 58 Microsiemens/cm. The lake of the Golden group was anaerobic at the bottom and had relatively high concentrations of dissolved organic carbon and dissolved metals, and a lower light transmission than the other lakes studied. One of the unnamed lakes had relatively high concentrations of phytoplankton and dissolved organic carbon and relatively low levels of light transmission. Comparisons of lake data to acid-sensitivity thresholds for specific conductance and alkalinity indicated that all of the lakes except Allen would be sensitive to acidic precipitation. The small sizes of the lakes, and their locations in basins of high precipitation and weathering-resistant rock types, enhance their sensitivity. None of the

  13. 'Pitted' to 'Pleasing' in 20 min.

    PubMed

    Sinha, Soumya; Vorse, Kirankumar Sudulakunta; Kariya, Pratik B; Mallikarjuna, Rachappa

    2015-06-29

    In recent times, as a result of extensive drinking water fluoridation, the number of patients affected by fluorosis has increased considerably. The purpose of this clinical report is to describe the use of enamel microabrasion for a patient with severe fluorosis using 37% phosphoric acid and pumice mixture. The results were pleasing, and hence 37% phosphoric acid can be recommended as a safe and easily available alternative in microabrasion procedures.

  14. 'Pitted' to 'Pleasing' in 20 min.

    PubMed

    Sinha, Soumya; Vorse, Kirankumar Sudulakunta; Kariya, Pratik B; Mallikarjuna, Rachappa

    2015-01-01

    In recent times, as a result of extensive drinking water fluoridation, the number of patients affected by fluorosis has increased considerably. The purpose of this clinical report is to describe the use of enamel microabrasion for a patient with severe fluorosis using 37% phosphoric acid and pumice mixture. The results were pleasing, and hence 37% phosphoric acid can be recommended as a safe and easily available alternative in microabrasion procedures. PMID:26123469

  15. Nobody’s perfect: can irregularities in pit structure influence vulnerability to cavitation?

    PubMed Central

    Plavcová, Lenka; Jansen, Steven; Klepsch, Matthias; Hacke, Uwe G.

    2013-01-01

    Recent studies have suggested that species-specific pit properties such as pit membrane thickness, pit membrane porosity, torus-to-aperture diameter ratio and pit chamber depth influence xylem vulnerability to cavitation. Despite the indisputable importance of using mean pit characteristics, considerable variability in pit structure within a single species or even within a single pit field should be acknowledged. According to the rare pit hypothesis, a single pit that is more air-permeable than many neighboring pits is sufficient to allow air-seeding. Therefore, any irregularities or morphological abnormalities in pit structure allowing air-seeding should be associated with increased vulnerability to cavitation. Considering the currently proposed models of air-seeding, pit features such as rare, large pores in the pit membrane, torus extensions, and plasmodesmatal pores in a torus can represent potential glitches. These aberrations in pit structure could either result from inherent developmental flaws, or from damage caused to the pit membrane by chemical and physical agents. This suggests the existence of interesting feedbacks between abiotic and biotic stresses in xylem physiology. PMID:24273549

  16. Applications of multi-season hyperspectral remote sensing for acid mine water characterization and mapping of secondary iron minerals associated with acid mine drainage

    NASA Astrophysics Data System (ADS)

    Davies, Gwendolyn E.

    Acid mine drainage (AMD) resulting from the oxidation of sulfides in mine waste is a major environmental issue facing the mining industry today. Open pit mines, tailings ponds, ore stockpiles, and waste rock dumps can all be significant sources of pollution, primarily heavy metals. These large mining-induced footprints are often located across vast geographic expanses and are difficult to access. With the continuing advancement of imaging satellites, remote sensing may provide a useful monitoring tool for pit lake water quality and the rapid assessment of abandoned mine sites. This study explored the applications of laboratory spectroscopy and multi-season hyperspectral remote sensing for environmental monitoring of mine waste environments. Laboratory spectral experiments were first performed on acid mine waters and synthetic ferric iron solutions to identify and isolate the unique spectral properties of mine waters. These spectral characterizations were then applied to airborne hyperspectral imagery for identification of poor water quality in AMD ponds at the Leviathan Mine Superfund site, CA. Finally, imagery varying in temporal and spatial resolutions were used to identify changes in mineralogy over weathering overburden piles and on dry AMD pond liner surfaces at the Leviathan Mine. Results show the utility of hyperspectral remote sensing for monitoring a diverse range of surfaces associated with AMD.

  17. Evaporative respiratory cooling augments pit organ thermal detection in rattlesnakes.

    PubMed

    Cadena, Viviana; Andrade, Denis V; Bovo, Rafael P; Tattersall, Glenn J

    2013-12-01

    Rattlesnakes use their facial pit organs to sense external thermal fluctuations. A temperature decrease in the heat-sensing membrane of the pit organ has the potential to enhance heat flux between their endothermic prey and the thermal sensors, affect the optimal functioning of thermal sensors in the pit membrane and reduce the formation of thermal "afterimages", improving thermal detection. We examined the potential for respiratory cooling to improve strike behaviour, capture, and consumption of endothermic prey in the South American rattlesnake, as behavioural indicators of thermal detection. Snakes with a higher degree of rostral cooling were more accurate during the strike, attacking warmer regions of their prey, and relocated and consumed their prey faster. These findings reveal that by cooling their pit organs, rattlesnakes increase their ability to detect endothermic prey; disabling the pit organs caused these differences to disappear. Rattlesnakes also modify the degree of rostral cooling by altering their breathing pattern in response to biologically relevant stimuli, such as a mouse odour. Our findings reveal that low humidity increases their ability to detect endothermic prey, suggesting that habitat and ambush site selection in the wild may be influenced by external humidity levels as well as temperature.

  18. Breaking of Apricot Pits by Using a Mechanical System

    NASA Astrophysics Data System (ADS)

    Polat, R.; Aktas, T.; Gezer, I.; Atay, U.; Bilim, H. I. C.

    The objective of this research was to investigate the effects of heating process and warping effect on breaking of apricot pits and obtaining of its kernel without damage. For this aim, heating process (350°C) was applied to apricot pits. Heated pits were fallen onto the rotating disc and they were warped to warping wall by centrifuge effect. Warping velocity was adjusted by changing of rotating disc revolution that was driven by an electric engine. Three different disc revolution namely 400, 500 and 600 min-1 and 4 different moisture contents of apricot pits namely 6.7, 15.5, 22.2 and 31.5% were used in the experiments. As a result, it was found that increasing of moisture content was increased amount of breaking and also sound kernel ratio. Increasing of disc revolution increased ratio of damaged kernel. The highest breaking amount was determined for experiment with heated pits that had 31.5% moisture content and warped with 400 min-1 disk revolution.

  19. Stochastic nature of clathrin-coated pit assembly

    NASA Astrophysics Data System (ADS)

    Banerjee, Anand; Berezhkovskii, Alexander; Nossal, Ralph

    2013-03-01

    Clathrin-mediated endocytosis is a complex process through which eukaryotic cells internalize various macromolecules (cargo). The process occurs via the formation of invaginations on the cell membrane, called clathrin-coated pits (CCPs). The dynamics of CCP formation shows remarkable variability. After initiation, a fraction of CCPs, called ``productive pits'', bind to cargo and then grow and mature into clathrin-coated vesicles (CCVs). In contrast, a large fraction of CCPs, called ``abortive pits'', fail to bind to cargo, grow only up to intermediate sizes and then disassemble. There is notable heterogeneity in the lifetimes of both productive and abortive pits. We propose a stochastic model of CCP dynamics to explain these experimental observations. Our model includes a kinetic scheme for CCP assembly and a related functional form for the dependence of free energy of a CCP on its size. Using this model, we calculate the lifetime distribution of abortive pits (via Monte Carlo simulation) and show that the distribution fits experimental data very well. By fitting the data we determine the free energy of CCP formation and show that CCPs without cargo are energetically unstable. We also suggest a mechanism by which cargo binding stabilizes CCPs and facilitates their growth.

  20. Great Lakes

    USGS Publications Warehouse

    Edsall, Thomas A.; Mac, Michael J.; Opler, Paul A.; Puckett Haecker, Catherine E.; Doran, Peter D.

    1998-01-01

    The wild plants and animals and the natural systems that support them in the Great Lakes region are valuable resources of considerable local, regional, and national interest. They are also, in part, transboundary resources that the U.S. shares with its Canadian neighbors to the north. The way these resources are changing over time is inadequately known and is a concern for resource users and for those charged with managing and protecting these unique and valuable resources. This chapter describes the wild plants and animals and the systems that support them in the Great Lakes region; addresses their condition; and points out the gaps in our knowledge about them that, if filled, would aid in their conservation and appropriate use.

  1. The Geology and Petrography of Crater Lake National Park

    USGS Publications Warehouse

    Diller, Joseph Silas; Patton, Horace Bushnell

    1902-01-01

    Origin of the name Mount Mazama - A great impetus to the spread of information concerning Crater Lake was given by the Mazamas of Portland, Oreg., who held a meeting at the lake in August, 1896, which attracted many visitors. The principal features in the history of the lake had previously been made out, and the Mazamas, recognizing the fact that the great peak which was nearly destroyed in preparing the pit for the lake had no name, gave it the name of their own society. Upon the rim of the lake are a number of small peaks, each having its own designation. The term Mount Mazama refers to the whole rim encircling the lake. It is but a mere remnant of the once lofty peak, the real Mount Mazama, which rose far into the region of eternal snow. To get a basis for reconstructing the original Mount Mazama it is necessary to study in detail the structure and composition of its foundation, now so attractively displayed in the encircling cliffs of Crater Lake.

  2. Dissolution kinetics and etch pit studies of potassium aluminium sulphate

    NASA Astrophysics Data System (ADS)

    van der Hoek, B.; Van Enckevort, W. J. P.; Van Der Linden, W. H.

    1983-03-01

    The dissolution process of the {111} faces of potash alum is studied, both by microtopographic examinations of the etch pit patterns and by measurement of the dissolution kinetics in a rotating disc crystallizer. Both methods showed that the Cabrera-Levine dissolution theory holds for the two most common dislocation types ending on the {111} faces of potash alum. On the basis of the rotating disc experiments, the interfacial supersaturation of the etch pit experiments was roughly estimated. Using this, it was found that at interfacial supersaturations below -0.6% (dislocations with <110> Burgers vector) or below -0.85% (dislocations with <100> Burgers vector) numerous etch pits related to those dislocation types appeared. Below those undersaturations the dissolution process is mainly determined by volume diffusion. From the critical undersaturation, determined in the rotating disc crystallizer, the value of the edge free energy of a step was found to be approximately 0.01 J/m 2.

  3. State Waste Discharge Permit application: 200-W Powerhouse Ash Pit

    SciTech Connect

    Atencio, B.P.

    1994-06-01

    As part of the Hanford Federal Facility Agreement and Consent Order negotiations; the US Department of Energy, Richland Operations Office, the US Environmental Protection Agency, and the Washington State Department of Ecology agreed that liquid effluent discharges to the ground on the Hanford Site which affect groundwater or have the potential to affect groundwater would be subject to permitting under the structure of Chapter 173-216 (or 173-218 where applicable) of the Washington Administrative Code, the State Waste Discharge Permit Program. This document constitutes the State Waste Discharge Permit application for the 200-W Powerhouse Ash Pit. The 200-W Powerhouse Ash Waste Water discharges to the 200-W Powerhouse Ash Pit via dedicated pipelines. The 200-W Powerhouse Ash Waste Water is the only discharge to the 200-W Powerhouse Ash Pit. The 200-W Powerhouse is a steam generation facility consisting of a coal-handling and preparation section and boilers.

  4. State Waste Discharge Permit application: 200-E Powerhouse Ash Pit

    SciTech Connect

    Atencio, B.P.

    1994-06-01

    As part of the Hanford Federal Facility Agreement and Consent Order negotiations, the US Department and Energy, Richland Operations Office, the US Environmental Protection Agency, and the Washington State Department of Ecology agreed that liquid effluent discharges to the ground on the Hanford Site which affect groundwater or have the potential to affect groundwater would be subject to permitting under the structure of Chapter 173-216 (or 173-218 where applicable) of the Washington Administrative Code, the State Waste Discharge Permit Program. This document constitutes the State Waste Discharge Permit application for the 200-E Powerhouse Ash Pit. The 200-E Powerhouse Ash Waste Water discharges to the 200-E Powerhouse Ash Pit via dedicated pipelines. The 200-E Ash Waste Water is the only discharge to the 200-E Powerhouse Ash Pit. The 200-E Powerhouse is a steam generation facility consisting of a coal-handling and preparation section and boilers.

  5. Fukushima Nuclear Accident Recorded in Tibetan Plateau Snow Pits

    PubMed Central

    Wang, Ninglian; Wu, Xiaobo; Kehrwald, Natalie; Li, Zhen; Li, Quanlian; Jiang, Xi; Pu, Jianchen

    2015-01-01

    The β radioactivity of snow-pit samples collected in the spring of 2011 on four Tibetan Plateau glaciers demonstrate a remarkable peak in each snow pit profile, with peaks about ten to tens of times higher than background levels. The timing of these peaks suggests that the high radioactivity resulted from the Fukushima nuclear accident that occurred on March 11, 2011 in eastern Japan. Fallout monitoring studies demonstrate that this radioactive material was transported by the westerlies across the middle latitudes of the Northern Hemisphere. The depth of the peak β radioactivity in each snow pit compared with observational precipitation records, suggests that the radioactive fallout reached the Tibetan Plateau and was deposited on glacier surfaces in late March 2011, or approximately 20 days after the nuclear accident. The radioactive fallout existed in the atmosphere over the Tibetan Plateau for about one month. PMID:25658094

  6. Comparative treatment effectiveness of conventional trench and seepage pit systems.

    PubMed

    Field, J P; Farrell-Poe, K L; Walworth, J L

    2007-03-01

    On-site wastewater treatment systems can be a potential source of groundwater contamination in regions throughout the United States and other parts of the world. Here, we evaluate four conventional trench systems and four seepage pit systems to determine the relative effectiveness of these systems for the treatment of septic tank effluent in medium- to coarse-textured arid and semiarid soils. Soil borings were advanced up to twice the depth of the trenches (4 m) and seepage pits (15 m) at two horizontal distances (30 cm and 1.5 m) from the sidewalls of the systems. Soil samples were analyzed for various biological and chemical parameters, including Escherichia coli, total coliform, pH, total organic carbon, total dissolved solids, total nitrogen, ammonium-nitrogen, and nitrate-nitrogen. Most soil parameters investigated approached background levels more rapidly near the trenches than the seepage pits, as sampling distance increased both vertically and horizontally from the sidewalls of the systems.

  7. Pit Distribution Design for Computer-Generated Waveguide Holography

    NASA Astrophysics Data System (ADS)

    Yagi, Shogo; Imai, Tadayuki; Ueno, Masahiro; Ohtani, Yoshimitsu; Endo, Masahiro; Kurokawa, Yoshiaki; Yoshikawa, Hiroshi; Watanabe, Toshifumi; Fukuda, Makoto

    2008-02-01

    Multilayered waveguide holography (MWH) is one of a number of page-oriented data multiplexing holographies that will be applied to optical data storage and three-dimensional (3D) moving images. While conventional volumetric holography using photopolymer or photorefractive materials requires page-by-page light exposure for recording, MWH media can be made by employing stamping and laminating technologies that are suitable for mass production. This makes devising an economical mastering technique for replicating holograms a key issue. In this paper, we discuss an approach to pit distribution design that enables us to replace expensive electron beam mastering with economical laser beam mastering. We propose an algorithm that avoids the overlapping of even comparatively large adjacent pits when we employ laser beam mastering. We also compensate for the angular dependence of the diffraction power, which strongly depends on pit shape, by introducing an enhancement profile so that a diffracted image has uniform intensity.

  8. Fukushima nuclear accident recorded in Tibetan Plateau snow pits.

    PubMed

    Wang, Ninglian; Wu, Xiaobo; Kehrwald, Natalie; Li, Zhen; Li, Quanlian; Jiang, Xi; Pu, Jianchen

    2015-01-01

    The β radioactivity of snow-pit samples collected in the spring of 2011 on four Tibetan Plateau glaciers demonstrate a remarkable peak in each snow pit profile, with peaks about ten to tens of times higher than background levels. The timing of these peaks suggests that the high radioactivity resulted from the Fukushima nuclear accident that occurred on March 11, 2011 in eastern Japan. Fallout monitoring studies demonstrate that this radioactive material was transported by the westerlies across the middle latitudes of the Northern Hemisphere. The depth of the peak β radioactivity in each snow pit compared with observational precipitation records, suggests that the radioactive fallout reached the Tibetan Plateau and was deposited on glacier surfaces in late March 2011, or approximately 20 days after the nuclear accident. The radioactive fallout existed in the atmosphere over the Tibetan Plateau for about one month.

  9. Impact of Acid Mine Drainage on the hydrogeological system at Sia, Cyprus

    NASA Astrophysics Data System (ADS)

    Ng, Stephen; Malpas, John

    2013-04-01

    Discontinued mining of the volcanogenic massive sulphide ore bodies of Cyprus has left significant environmental concerns including Acid Mine Drainage. Remnant sulphide ore and tailings in waste dumps react with oxygenated rainwater to produce sulphuric acid, a process which is multiplied when metal-loving acidophilic bacteria are present. Given that Cyprus has a Mediterranean climate, characterized by its warm and dry summers and cool and wet winters, the low pH effluent with high levels of trace elements, particularly metals, is leached out of the waste tips particularly during the wet season. The Sia site includes an open mine-pit lake, waste rock and tailings dumps, a river leading to a downstream dam-lake, and a localised groundwater system. The study intends to: identify the point source and nature of contamination; analyze the mechanism and results of local acid generation; and understand how the hydrogeological system responds to seasonal variations. During two sampling campaigns, in the wet and dry seasons of 2011, water samples were collected from the mine pit lake, from upstream of the adjacent river down to the dam catchment, and from various boreholes close to the sulphide mine. The concentration of ions in waters varies between wet and dry seasons but, in both, relative amounts are directly related to pH. In the mine-pit lake, Fe, Mn, Mg, Cu, Pb, Zn, Ni, Co and Cd are found in higher concentrations in the dry season, as a result of substantial evaporation of water. The Sia River runs continuously in the wet season, and waters collected close to the waste tips have pH as low as 2.5 and higher concentrations of Al, Cu, Fe and Zn. Further downstream there is a significant decrease in trace metal contents with a concomitant rise of pH. Al and Fe dominate total cation content when pH is lower than 4. Al is derived from the weathering of clay minerals, especially during the wet season. Fe is derived from the oxidation of pyrite. Once pH's exceed 4, a white

  10. Relationship Between Foveal Cone Specialization and Pit Morphology in Albinism

    PubMed Central

    Wilk, Melissa A.; McAllister, John T.; Cooper, Robert F.; Dubis, Adam M.; Patitucci, Teresa N.; Summerfelt, Phyllis; Anderson, Jennifer L.; Stepien, Kimberly E.; Costakos, Deborah M.; Connor, Thomas B.; Wirostko, William J.; Chiang, Pei-Wen; Dubra, Alfredo; Curcio, Christine A.; Brilliant, Murray H.; Summers, C. Gail; Carroll, Joseph

    2014-01-01

    Purpose. Albinism is associated with disrupted foveal development, though intersubject variability is becoming appreciated. We sought to quantify this variability, and examine the relationship between foveal cone specialization and pit morphology in patients with a clinical diagnosis of albinism. Methods. We recruited 32 subjects with a clinical diagnosis of albinism. DNA was obtained from 25 subjects, and known albinism genes were analyzed for mutations. Relative inner and outer segment (IS and OS) lengthening (fovea-to-perifovea ratio) was determined from manually segmented spectral domain-optical coherence tomography (SD-OCT) B-scans. Foveal pit morphology was quantified for eight subjects from macular SD-OCT volumes. Ten subjects underwent imaging with adaptive optics scanning light ophthalmoscopy (AOSLO), and cone density was measured. Results. We found mutations in 22 of 25 subjects, including five novel mutations. All subjects lacked complete excavation of inner retinal layers at the fovea, though four subjects had foveal pits with normal diameter and/or volume. Peak cone density and OS lengthening were variable and overlapped with that observed in normal controls. A fifth hyper-reflective band was observed in the outer retina on SD-OCT in the majority of the subjects with albinism. Conclusions. Foveal cone specialization and pit morphology vary greatly in albinism. Normal cone packing was observed in the absence of a foveal pit, suggesting a pit is not required for packing to occur. The degree to which retinal anatomy correlates with genotype or visual function remains unclear, and future examination of larger patient groups will provide important insight on this issue. PMID:24845642

  11. Upper Extremity Injuries in NASCAR Drivers and Pit Crew

    PubMed Central

    Wertman, Gary; Gaston, R. Glenn; Heisel, William

    2016-01-01

    Background: Understanding the position-specific musculoskeletal forces placed on the body of athletes facilitates treatment, prevention, and return-to-play decisions. While position-specific injuries are well documented in most major sports, little is known about the epidemiology of position-specific injuries in National Association for Stock Car Automobile Racing (NASCAR) drivers and pit crew. Purpose: To investigate position-specific upper extremity injuries in NASCAR drivers and pit crew members. Study Design: Descriptive epidemiological study. Methods: A retrospective chart review was performed to assess position-specific injuries in NASCAR drivers and pit crew members. Included in the study were patients seen by a single institution between July 2003 and October 2014 with upper extremity injuries from race-related NASCAR events or practices. Charts were reviewed to identify the diagnosis, mechanism of injury, and position of each patient. Results: A total of 226 NASCAR team members were treated between July 2003 and October 2014. Of these, 118 injuries (52%) occurred during NASCAR racing events or practices. The majority of these injuries occurred in NASCAR changers (42%), followed by injuries in drivers (16%), carriers (14%), jack men (11%), fuel men (9%), and utility men (8%). The majority of the pit crew positions are at risk for epicondylitis, while drivers are most likely to experience neuropathies, such as hand-arm vibration syndrome. The changer sustains the most hand-related injuries (42%) on the pit crew team, while carriers commonly sustain injuries to their digits (29%). Conclusion: Orthopaedic injuries in NASCAR vary between positions. Injuries in NASCAR drivers and pit crew members are a consequence of the distinctive forces associated with each position throughout the course of the racing season. Understanding these forces and position-associated injuries is important for preventive measures and facilitates diagnosis and return-to-play decisions

  12. The Influence of Radiation on Pit Solution Chemistry as it Pertains to the Transition from Metastable to Stable Pitting in Steels.

    SciTech Connect

    Galuszka-Muga, Barbara; Muga, Luis M.

    2006-12-31

    Previous work relevant to current efforts is summarized. A description of an improved version of a new electrochemical probe, the ArtPit, is given. The distinct feature of the probe for investigating metastable pitting of carbon steels is specified and compared to other approaches. The electrochemical response of the ArtPit under the gamma irradiation and elevated temperature conditions that occur at high level waste (HLW) storage tanks is presented. In particular, the Tafel slope determinations and chemical analyses of the ArtPit confined volume electrolyte are described. Based on results a possible approach for reducing the corrosion rate of HLW tank walls is suggested. Additional statistical analysis of the occurrence of short duration (passivated pits) and long term (stable pitting) electrochemical pulses (current surges) during exposure confirm that radiation enhances the occurrence of both more and smaller sized pits due to increased likelihood of repassivation.

  13. The effects of wildfire on mercury and stable isotopes (δ(15)N, δ(13)C) in water and biota of small boreal, acidic lakes in southern Norway.

    PubMed

    Moreno, Clara E; Fjeld, Eirik; Lydersen, Espen

    2016-03-01

    Effects of wildfire on main water chemistry and mercury (Hg) in water and biota were studied during the first 4 post-fire years. After severe water chemical conditions during hydrological events a few months following the wildfire, the major water chemical parameters were close to pre-fire conditions 4 years after the fire. Concentrations of total Hg and methyl Hg in the surface water 4 years after the fire ranged between 1.17-2.63 ng L(-1) and 0.053-0.188 ng L(-1), respectively. Both variables were positive and strongly correlated with total organic carbon (TOC), TOC-related variables (color, UV absorbance), total phosphorous, and total iron. In addition, MeHg was positively correlated with total nitrogen and chlorophyll-a. The concurrence of increased concentrations of nutrients and chlorophyll-a in the lakes, the more enriched δ(15)N-signatures and higher Hg levels in fish 2 years after the fire, might be a result of the wildfire. However, natural factors as year-to-year variations in thermocline depth and suboxic status in the lakes make it difficult to draw any strong conclusions about wildfire effects on Hg in the biota from our investigated lakes.

  14. Perchlorate in Lake Water from an Operating Diamond Mine.

    PubMed

    Smith, Lianna J D; Ptacek, Carol J; Blowes, David W; Groza, Laura G; Moncur, Michael C

    2015-07-01

    Mining-related perchlorate [ClO4(-)] in the receiving environment was investigated at the operating open-pit and underground Diavik diamond mine, Northwest Territories, Canada. Samples were collected over four years and ClO4(-) was measured in various mine waters, the 560 km(2) ultraoligotrophic receiving lake, background lake water and snow distal from the mine. Groundwaters from the underground mine had variable ClO4(-) concentrations, up to 157 μg L(-1), and were typically an order of magnitude higher than concentrations in combined mine waters prior to treatment and discharge to the lake. Snow core samples had a mean ClO4(-) concentration of 0.021 μg L(-1) (n=16). Snow and lake water Cl(-)/ClO4(-) ratios suggest evapoconcentration was not an important process affecting lake ClO4(-) concentrations. The multiyear mean ClO4(-) concentrations in the lake were 0.30 μg L(-1) (n = 114) in open water and 0.24 μg L(-1) (n = 107) under ice, much below the Canadian drinking water guideline of 6 μg L(-1). Receiving lake concentrations of ClO4(-) generally decreased year over year and ClO4(-) was not likely [biogeo]chemically attenuated within the receiving lake. The discharge of treated mine water was shown to contribute mining-related ClO4(-) to the lake and the low concentrations after 12 years of mining were attributed to the large volume of the receiving lake.

  15. Lower lip pits: van der woude or kabuki syndrome?

    PubMed

    David-Paloyo, Ferri P; Yang, Xuecai; Lin, Ju-Li; Wong, Fen-Hwa; Wu-Chou, Yah-Huei; Lo, Lun-Jou

    2014-11-01

    Kabuki syndrome (KS) is a multiple congenital anomaly/mental retardation syndrome with characteristic facial features. Despite more than 350 documented cases and recent correlation of MLL2 mutations as a genetic cause, its full clinical spectrum is still being defined. This report describes two patients who were initially diagnosed with Van der Woude syndrome (VWS) based on the presence of lower lip pits. However, this finding can occur with KS, albeit infrequently. For patients with lower lip pits, a thorough evaluation should be made to distinguish between VWS and KS, as there are differences in long-term prognosis. PMID:24088119

  16. Description of work for 216-U-Pond test pits

    SciTech Connect

    Kelty, G.G.

    1993-08-11

    This description of work (DOW) details the field activities associated with the test pit excavation and soil sampling at the 216- U-10 Pond (U-10 Pond) in the 200 West Area and will serve as a field guide for those performing the work. It will be used in conjunction with the 200-UP-2 Resource Conservation and Recovery Act of 1976 (RCRA) Facility Investigation/Corrective Measures Study (DOE-RL 1993a, [LFI]) and Site Characterization Manual (WHC 1988a). Test pits will be constructed to characterize the vertical extent of contaminants in sediments within and beneath the former U-10 pond.

  17. Centrifugation applied to drilling fluids and sludge pit cleanup

    SciTech Connect

    Grichar, C.N.

    1987-01-01

    Solid bowl decanting centrifuges are an indispensible part of a well-designed, modern oilfield solids control system. They have application throughout the entire drilling process and during the post-drilling sludge pit cleanup operation. As drilling costs rise further, and as environmental regulations become stricter, the decanting centrifuge will become even more important and contribute more heavily to the overall cost effectiveness of the drilling process. The significance of this technology as applied to drilling fluids and sludge pit cleanup is emphasized in this paper.

  18. Ablation layers to prevent pitting in laser peening

    DOEpatents

    Hackel, Lloyd A

    2016-08-09

    A hybrid ablation layer that comprises a separate under layer is applied to a material to prevent pitting resulting from laser peening. The underlayer adheres to the surface of the workpiece to be peened and does not have bubbles and voids that exceed an acceptable size. One or more overlayers are placed over and in contact with the underlayer. Any bubbles formed under the over layers are insulated from the surface to be peened. The process significantly reduces the incidence of pits on peened surfaces.

  19. Development of an automated pit packaging system for Pantex

    SciTech Connect

    Fahrenholtz, J.C.

    1997-09-01

    Sandia National Laboratories is developing a system that uses robots to package pits at Pantex in the AT-400A pit storage and transportation container. This report will give an overview of the AT-400A packaging process, and the parts of the overall AT-400A packaging operation that will be performed robotically. The process employed to move from development in the laboratory at Sandia to production use at Pantex will be described. Finally, important technology components being developed for and incorporated into the robotic system will be described. 7 refs., 9 figs.

  20. Water quality of Fremont Lake and New Fork Lakes, western Wyoming; a progress report

    USGS Publications Warehouse

    Peterson, D.A.; Averett, R.C.; Mora, K.L.

    1987-01-01

    Fremont Lake and New Fork Lakes in the New Fork River drainage of western Wyoming were selected for a comprehensive study of hydrologic processes affecting mountain lakes in the Rocky Mountains. Information is needed about lakes in this area to assess their response to existing and planned development. The concerns include regional issues such as acid precipitation from gas-sweetening plants, coal-fired powerplants, and smelters, as well as local issues, such as shoreline development and raising outlet control structures. Onsite measurements indicated strong thermal stratification in the lakes during the summer. Isothermal conditions occurred during December 1983 and May 1984. Mean phytoplankton concentrations were less than 5,000 cells/ml, and chlorophyll a concentrations were weakly correlated with phytoplankton concentrations. Zooplankton concentrations were small, less than 6 organisms/L. The numbers of benthic invertebrates/unit area in Fremont Lake were extremely small. The lake waters and inflow and outflow streams were chemically dilute solutions. Mean dissolved-solids concentrations were 13 mg/L in Fremont Lake and 24 mg/L in New Fork Lakes. Calcium and bicarbonate were the predominant ions. Concentrations of phosphorus and nitrogen usually were less than detection limits. Trace-metals concentrations in the lakes were similar to those in precipitation and generally were small. Dissolved organic-carbon concentrations were about 1 mg/L. Concentrations of fulvic and humic acids were relatively large in the inlet of Fremont Lake during the spring. Pine Creek has deposited 800 metric tons of sediment, on an annual average, to the delta of Fremont Lake. Most sediment is deposited during spring runoff. (USGS)

  1. The effects of pitting on fatigue crack nucleation in 7075-T6 aluminum alloy

    NASA Technical Reports Server (NTRS)

    Ma, LI; Hoeppner, David W.

    1994-01-01

    A high-strength aluminum alloy, 7075-T6, was studied to quantitatively evaluate chemical pitting effects of its corrosion fatigue life. The study focused on pit nucleation, pit growth, and fatigue crack nucleation. Pitting corrosion fatigue experiments were conducted in 3.5 percent NaCl aqueous solution under constant amplitude sinusoidal loading at two frequencies, 5 and 20 Hz. Smooth and unnotched specimens were used in this investigation. A video recording system was developed to allow in situ observation of the surface changes of the specimens during testing. The results indicated that pitting corrosion considerably reduces the fatigue strength by accelerating fatigue crack nucleation. A metallographic examination was conducted on the specimens to evaluate the nature of corrosion pits. First, the actual shapes of the corrosion pits were evaluated by cross-sectioning the pits. Secondly, the relation between corrosion pits and microstructure was also investigated. Finally, the possibility of another corrosion mechanism that might be involved in pitting was explored in this investigation. The fractography of the tested specimens showed that corner corrosion pits were responsible for fatigue crack nucleation in the material due to the associated stress concentration. The pits exhibited variance of morphology. Fatigue life for the experimental conditions appeared to be strongly dependent on pitting kinetics and the crack nucleation stage.

  2. Long term monitoring of water basin of an abandoned copper open pit mine

    NASA Astrophysics Data System (ADS)

    Nikolov, H.; Borisova, D.

    2012-04-01

    Nonoperating open pit mines, very often as a matter of fact abandoned, create serious ecological risk for the region of their location especially for the quality of the water since the rainfall fills the bottom of the pit forming water body having different depth. This water as a rule has very high concentration of the metals in it and is highly toxic. One example for such opencast, idle copper mine is Medet located in the central part of Bulgaria who was started for exploitation in 1964 and at that moment being the largest in Europe for production of copper concentrate. In the vicinity of it after autumn and spring rains there are many cases reported for water contamination by heavy metals such as arsenic, copper, cadmium in the rivers running close to this open pit mine. This justifies the need for long term and sustainable monitoring of the area of the water basin of this idle mine in order to estimate its acid drainage and imaging spectroscopy combined with is-situ investigations is proved to provide reliable results about the area of the water table. In the course of this study we have investigated historical data gathered by remote sensing which allowed us to make conclusions about the year behavior of this area. Our expectations are that the results of this research will help in the rehabilitation process of this idle mine and will provide the local authorities engaged in water quality monitoring with a tool to estimate the possible damage caused to the local rivers and springs. With this research we also would like to contribute to the fulfillment of the following EU Directives: Directive 2006/21/°C on the Management of Waste from the Extractive Industries and Directive 2004/35/ °C on Environmental Liability with regard to the Prevention and Remedying of Environmental Damage.

  3. Dating problems with selected mining lakes and the adjacent groundwater body in Lusatia, Germany.

    PubMed

    Seebach, Anne; von Rohden, Christoph; Ilmberger, Johann; Weise, Stephan M; Knoller, Kay

    2010-09-01

    This study presents selected results, applying environmental tracers to investigate lake water-groundwater interactions at two study sites located in Lusatia, Germany. The focus of the investigations were two meromictic pit lakes and their adjacent aquifers. In order to follow hydrodynamic processes between lake and groundwater, mixing patterns within the lakes as well as ages of lake and groundwater, water samples of ground- and lake water were collected at three occasions, representing summer and winter conditions in the aquatic systems. The water samples were analysed for stable isotopes (deuterium, oxygen-18) and tritium and sulphurhexafluoride (SF(6) concentration). Lake water profiles of conductivity and (18)O could validate the permanent stratification pattern of both the lakes. Groundwater data sets showed a heterogeneous local distribution in stable isotope values between rain and lake water. A two-component mixing model had been adopted only from (18)O data to determine lake water proportions in the surrounding groundwater wells in order to correct measured tritium and SF(6) concentrations in groundwater samples. This procedure had been hampered by upstream-located wells indicating strong (18)O enrichment in groundwater samples. However, rough groundwater ages were estimated. For both study sites, Piston flow ages between 12.9 and 27.7 years were calculated. The investigations showed the good agreement between two different environmental dating tools, considering the marginal data sets.

  4. Monitoring of adult Lost River and shortnose suckers in Clear Lake Reservoir, California, 2008–2010

    USGS Publications Warehouse

    Hewitt, David A.; Hayes, Brian S.

    2013-01-01

    Problems with inferring status and population dynamics from size composition data can be overcome by a robust capture-recapture program that follows the histories of PIT-tagged individuals. Inferences from such a program are currently hindered by poor detection rates during spawning seasons with low flows in Willow Creek, which indicate that a key assumption of capture-recapture models is violated. We suggest that the most straightforward solution to this issue would be to collect detection data during the spawning season using remote PIT tag antennas in the strait between the west and east lobes of the lake.

  5. SEASONAL VARIATIONS OF DISSOLVED MERCURY CONCENTRATIONS AT THE SULPHUR BANK MERCURY MINE, CLEAR LAKE, CALIFORNIA: IMPLICATIONS FOR MINE DRAINAGE MONITORING

    EPA Science Inventory

    The Sulphur Bank Mercury Mine in Lake County, California (SBMM) was operated from the 1860s through the 1950s. Mining for sulfur started with surface operations and then progressed to shaft and later open pit techniques to obtain mercury. SBMM is located adjacent to the shore o...

  6. Birth of a lava lake: Nyamulagira volcano 2011-2015

    NASA Astrophysics Data System (ADS)

    Coppola, D.; Campion, R.; Laiolo, M.; Cuoco, E.; Balagizi, C.; Ripepe, M.; Cigolini, C.; Tedesco, D.

    2016-03-01

    Since 1938, Nyamulagira volcano (Democratic Republic of Congo) has operated as a classic pressurized basaltic closed system, characterized by frequent dike-fed flank eruptions. However, on June 24, 2014, an active lava lake was observed in its summit, after a period of 76 years. The small lava lake is now exposed at the bottom of a pit-crater and is rising and growing. Based on satellite-derived infrared (IR) data, SO2 fluxes and periodic field surveys, we provide evidence that the development of the lava lake was gradual and occurred more than 2 years before it was first observed in the field. Notably, this process followed the voluminous 2011-2012 distal flank eruption and was coeval with weakening of the central rock column below the summit. Hence, the opening and development of the pit-crater favoured the continuous rise of fresh magma through the central conduit and promoted the gradual "re-birth" of the Nyamulagira lava lake. Budgeted volumes of magma erupted, and magma degassed at depth indicate that the formation of the lava lake is due to the draining and refilling of a shallow plumbing system (1-2 km depth), probably in response to the rift-parallel 2011-2012 distal eruption. We thus suggest that the transition from lateral to central activity did not result from a substantial change in the magma supply rate but, more likely, from the perturbation of the plumbing system (and related stress field) associated with the distal eruption. The processes observed at Nyamulagira are not unique and suggest that rift-fissure eruptions, in addition to triggering caldera collapses or lava lake drainages, may also induce a progressive resumption of central vent activity. Current activity at Nyamulagira represents a tangible and major hazard for the population living at the base of its southern flank.

  7. Azaphilones from an Acid Mine Extremophile Strain of a Pleurostomophora sp.

    PubMed

    Stierle, Andrea A; Stierle, Donald B; Girtsman, Teri; Mou, T C; Antczak, Christophe; Djaballah, Hakim

    2015-12-24

    An extremophilic fungus identified as a Pleurostomophora sp. was isolated from the Berkeley Pit, an acid mine waste lake. When grown in liquid culture, the fungus produced berkchaetoazaphilones A-C (1, 2, and 5), the red pigment berkchaetorubramine (6), and the known compound 4-(hydroxymethyl)quinoline. These compounds were evaluated as inhibitors of matrix metalloproteinase-3, caspase-1, and proinflammatory cytokine production in induced THP-1 cells. Berkchaetoazaphilone B (2) inhibited IL-1β, TNFα, and IL-6 production in the induced inflammasome assay and was cytotoxic toward human retinoblastoma cell line Y79 (IC50 = 1.1 μM), leukemia cell lines CCRF-CEM and SR, and the melanoma cell line LOX IMVI (IC50 = 10 μM). PMID:26641525

  8. 30 CFR 56.3131 - Pit or quarry wall perimeter.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Pit or quarry wall perimeter. 56.3131 Section 56.3131 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Ground...

  9. 30 CFR 56.3131 - Pit or quarry wall perimeter.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Pit or quarry wall perimeter. 56.3131 Section 56.3131 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Ground...

  10. 30 CFR 56.3131 - Pit or quarry wall perimeter.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Pit or quarry wall perimeter. 56.3131 Section 56.3131 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Ground...

  11. 30 CFR 56.3131 - Pit or quarry wall perimeter.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Pit or quarry wall perimeter. 56.3131 Section 56.3131 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Ground...

  12. THE IMPACT OF PHOSPHATE ON COPPER PITTING CORROSION

    EPA Science Inventory

    Pinhole leaks caused by extensive localized or pitting corrosion of copper pipes is a problem for many homeowners. Pinhole water leaks may result in water damage, mold growth, and costly repairs. A large water system in Florida has been addressing a widespread pinhole leak proble...

  13. Pitting behavior of aluminum ion implanted with nitrogen

    SciTech Connect

    McCafferty, E.; Natishan, P.M.; Hubler, G.K.

    1997-07-01

    Ion implantation of {approx} 2 at% N into aluminum increased the pitting potential in 0.1 M sodium chloride by an average of 0.35 V. Surface analysis by x-ray photoelectron spectroscopy showed implanted nitrogen was present as several species: NH{sub 4}{sup +}, NO or NH{sub 3} (as a ligand), AIN, and weakly bound or interstitial nitrogen. With anodic polarization, there was an increase in the total amount of nitrogen in the near-surface region, a decrease in the relative amount of nitride, and an increase in the relative amount of NO or NH{sub 3}. These changes resulted from migration of implanted nitrogen from the substrate into the near-surface region with partial conversion of the AIN species to NO or NH{sub 3}. It was suggested that the effect of implanted nitrogen on pitting behavior of aluminum is similar to that in nitrogen-containing stainless steels, where nitrogen at the metal surface inhibits the dissolution kinetics or aids the repassivation process in the pit by forming NH{sub 4}{sup +} ions that buffer the pit electrolyte.

  14. 80. ARAIII. Forming of the mechanical equipment pit in reactor ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    80. ARA-III. Forming of the mechanical equipment pit in reactor building (ARA-608). Camera facing northwest. September 22, 1958. Ineel photo no. 58-4675. Photographer: Jack L. Anderson. - Idaho National Engineering Laboratory, Army Reactors Experimental Area, Scoville, Butte County, ID

  15. Operational apron with pit hydrants in foreground, aircraft in background. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Operational apron with pit hydrants in foreground, aircraft in background. View to west - Offutt Air Force Base, Looking Glass Airborne Command Post, Operational & Hangar Access Aprons, Spanning length of northeast half of Project Looking Glass Historic District, Bellevue, Sarpy County, NE

  16. Heavy Duty Tireman. Open Pit Mining Job Training Series.

    ERIC Educational Resources Information Center

    McColman, Don

    This training outline for heavy duty tiremen, one in a series of eight outlines, is designed primarily for company training foremen or supervisors and for trainers to use as an industry-wide guideline for heavy equipment operator training in open pit mining in British Columbia. Intended as a guide for preparation of lesson plans both for classroom…

  17. 8. COLLAPSED AND SCATTERED BUILDING ON FLOOR OF PIT, WITH ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    8. COLLAPSED AND SCATTERED BUILDING ON FLOOR OF PIT, WITH PILE OF RHYOLITE BOULDERS IN BACKGROUND, VIEW TO SOUTH - Iron Springs Quarry, 150 feet west of Grand Loop Road, 20 miles east of U.S. Highway 287, West Thumb, Teton County, WY

  18. CONSTRUCTION PROGRESS PHOTO SHOWING EXCAVATION PIT FOR MAIN PROCESSING BUILDING ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    CONSTRUCTION PROGRESS PHOTO SHOWING EXCAVATION PIT FOR MAIN PROCESSING BUILDING (CPP-601) LOOKING NORTHWEST. INL PHOTO NUMBER NRTS-50-885. Unknown Photographer, 10/30/1950 - Idaho National Engineering Laboratory, Idaho Chemical Processing Plant, Fuel Reprocessing Complex, Scoville, Butte County, ID

  19. 62. Historic propellant piping diagram of oxidant pit at Building ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    62. Historic propellant piping diagram of oxidant pit at Building 202, January 6, 1956. NASA GRC drawing no. CF-101644. (On file at NASA Glenn Research Center). - Rocket Engine Testing Facility, GRC Building No. 202, NASA Glenn Research Center, Cleveland, Cuyahoga County, OH