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Sample records for water decomposition plant

  1. Nuclear driven water decomposition plant for hydrogen production

    NASA Technical Reports Server (NTRS)

    Parker, G. H.; Brecher, L. E.; Farbman, G. H.

    1976-01-01

    The conceptual design of a hydrogen production plant using a very-high-temperature nuclear reactor (VHTR) to energize a hybrid electrolytic-thermochemical system for water decomposition has been prepared. A graphite-moderated helium-cooled VHTR is used to produce 1850 F gas for electric power generation and 1600 F process heat for the water-decomposition process which uses sulfur compounds and promises performance superior to normal water electrolysis or other published thermochemical processes. The combined cycle operates at an overall thermal efficiency in excess of 45%, and the overall economics of hydrogen production by this plant have been evaluated predicated on a consistent set of economic ground rules. The conceptual design and evaluation efforts have indicated that development of this type of nuclear-driven water-decomposition plant will permit large-scale economic generation of hydrogen in the 1990s.

  2. [Effects of aquatic plants during their decay and decomposition on water quality].

    PubMed

    Tang, Jin-Yan; Cao, Pei-Pei; Xu, Chi; Liu, Mao-Song

    2013-01-01

    Taking 6 aquatic plant species as test objects, a 64-day decomposition experiment was conducted to study the temporal variation patterns of nutrient concentration in water body during the process of the aquatic plant decomposition. There existed greater differences in the decomposition rates between the 6 species. Floating-leaved plants had the highest decomposition rate, followed by submerged plants, and emerged plants. The effects of the aquatic plant species during their decomposition on water quality differed, which was related to the plant biomass density. During the decomposition of Phragmites australis, water body had the lowest concentrations of chemical oxygen demand, total nitrogen, and total phosphorus. In the late decomposition period of Zizania latifolia, the concentrations of water body chemical oxygen demand and total nitrogen increased, resulting in the deterioration of water quality. In the decomposition processes of Nymphoides peltatum and Nelumbo nucifera, the concentrations of water body chemical oxygen demand and total nitrogen were higher than those during the decomposition of other test plants. In contrast, during the decomposition of Potamogeton crispus and Myriophyllum verticillatum, water body had the highest concentrations of ammonium, nitrate, and total phosphorus. For a given plant species, the main water quality indices had the similar variation trends under different biomass densities. It was suggested that the existence of moderate plant residues could effectively promote the nitrogen and phosphorus cycles in water body, reduce its nitrate concentration to some extent, and decrease the water body nitrogen load. PMID:23717994

  3. The Conceptual Design of an Integrated Nuclearhydrogen Production Plant Using the Sulfur Cycle Water Decomposition System

    NASA Technical Reports Server (NTRS)

    Farbman, G. H.

    1976-01-01

    A hydrogen production plant was designed based on a hybrid electrolytic-thermochemical process for decomposing water. The sulfur cycle water decomposition system is driven by a very high temperature nuclear reactor that provides 1,283 K helium working gas. The plant is sized to approximately ten million standard cubic meters per day of electrolytically pure hydrogen and has an overall thermal efficiently of 45.2 percent. The economics of the plant were evaluated using ground rules which include a 1974 cost basis without escalation, financing structure and other economic factors. Taking into account capital, operation, maintenance and nuclear fuel cycle costs, the cost of product hydrogen was calculated at $5.96/std cu m for utility financing. These values are significantly lower than hydrogen costs from conventional water electrolysis plants and competitive with hydrogen from coal gasification plants.

  4. Water Limitation and Plant Inter-specific Competition Reduce Rhizosphere-Induced C Decomposition and Plant N Uptake

    Technology Transfer Automated Retrieval System (TEKTRAN)

    1. Plants can affect soil organic matter decomposition and mineralization through litter inputs, but also more directly through root-microbial interactions (rhizosphere effects). Depending on resource availability and plant species identity, these rhizosphere effects can be positive or negative. To...

  5. Thermochemical water decomposition processes

    NASA Technical Reports Server (NTRS)

    Chao, R. E.

    1974-01-01

    Thermochemical processes which lead to the production of hydrogen and oxygen from water without the consumption of any other material have a number of advantages when compared to other processes such as water electrolysis. It is possible to operate a sequence of chemical steps with net work requirements equal to zero at temperatures well below the temperature required for water dissociation in a single step. Various types of procedures are discussed, giving attention to halide processes, reverse Deacon processes, iron oxide and carbon oxide processes, and metal and alkali metal processes. Economical questions are also considered.

  6. Phlogopite Decomposition, Water, and Venus

    NASA Technical Reports Server (NTRS)

    Johnson, N. M.; Fegley, B., Jr.

    2005-01-01

    Venus is a hot and dry planet with a surface temperature of 660 to 740 K and 30 parts per million by volume (ppmv) water vapor in its lower atmosphere. In contrast Earth has an average surface temperature of 288 K and 1-4% water vapor in its troposphere. The hot and dry conditions on Venus led many to speculate that hydrous minerals on the surface of Venus would not be there today even though they might have formed in a potentially wetter past. Thermodynamic calculations predict that many hydrous minerals are unstable under current Venusian conditions. Thermodynamics predicts whether a particular mineral is stable or not, but we need experimental data on the decomposition rate of hydrous minerals to determine if they survive on Venus today. Previously, we determined the decomposition rate of the amphibole tremolite, and found that it could exist for billions of years at current surface conditions. Here, we present our initial results on the decomposition of phlogopite mica, another common hydrous mineral on Earth.

  7. Assessing plant residue decomposition in soil using DRIFT spectroscopy

    NASA Astrophysics Data System (ADS)

    Ouellette, Lance; Van Eerd, Laura; Voroney, Paul

    2016-04-01

    Assessment of the decomposition of plant residues typically involves the use of tracer techniques combined with measurements of soil respiration. This laboratory study evaluated use of Diffuse Reflectance Fourier Transform (DRIFT) spectroscopy for its potential to assess plant residue decomposition in soil. A sandy loam soil (Orthic Humic Gleysol) obtained from a field research plot was passed through a 4.75 mm sieve moist (~70% of field capacity) to remove larger crop residues. The experimental design consisted of a randomized complete block with four replicates of ten above-ground cover crop residue-corn stover combinations, where sampling time was blocked. Two incubations were set up for 1) Drift analysis: field moist soil (250 g ODW) was placed in 500 mL glass jars, and 2) CO2 evolution: 100 g (ODW) was placed in 2 L jars. Soils were amended with the plant residues (oven-dried at 60°C and ground to <2 mm) at rates equivalent to field mean above-ground biomass yields, then moistened to 60% water holding capacity and incubated in the dark at 22±3°C. Measurements for DRIFT and CO2-C evolved were taken after 0.5, 2, 4, 7, 10, 15, 22, 29, 36, 43, 50 64 and 72 d. DRIFT spectral data (100co-added scans per sample) were recorded with a Varian Cary 660 FT-IR Spectrometer equipped with an EasiDiff Diffuse Reflectance accessory operated at a resolution of 4 cm-1 over the mid-infrared spectrum from 4000 to 400 cm-1. DRIFT spectra of amended soils indicated peak areas of aliphatics at 2930 cm‑1, of aromatics at 1620, and 1530 cm‑1 and of polysaccharides at 1106 and 1036 cm-1. Evolved CO2 was measured by the alkali trap method (1 M NaOH); the amount of plant residue-C remaining in soil was calculated from the difference in the quantity of plant residue C added and the additional CO2-C evolved from the amended soil. First-order model parameters of the change in polysaccharide peak area over the incubation were related to those generated from the plant residue C decay

  8. Plant diversity effects on root decomposition in grasslands

    NASA Astrophysics Data System (ADS)

    Chen, Hongmei; Mommer, Liesje; van Ruijven, Jasper; de Kroon, Hans; Gessler, Arthur; Scherer-Lorenzen, Michael; Wirth, Christian; Weigelt, Alexandra

    2016-04-01

    Loss of plant diversity impairs ecosystem functioning. Compared to other well-studied processes, we know little about whether and how plant diversity affects root decomposition, which is limiting our knowledge on biodiversity-carbon cycling relationships in the soil. Plant diversity potentially affects root decomposition via two non-exclusive mechanisms: by providing roots of different substrate quality and/or by altering the soil decomposition environment. To disentangle these two mechanisms, three decomposition experiments using a litter-bag approach were conducted on experimental grassland plots differing in plant species richness, functional group richness and functional group composition (e.g. presence/absence of grasses, legumes, small herbs and tall herbs, the Jena Experiment). We studied: 1) root substrate quality effects by decomposing roots collected from the different experimental plant communities in one common plot; 2) soil decomposition environment effects by decomposing standard roots in all experimental plots; and 3) the overall plant diversity effects by decomposing community roots in their 'home' plots. Litter bags were installed in April 2014 and retrieved after 1, 2 and 4 months to determine the mass loss. We found that mass loss decreased with increasing plant species richness, but not with functional group richness in the three experiments. However, functional group presence significantly affected mass loss with primarily negative effects of the presence of grasses and positive effects of the presence of legumes and small herbs. Our results thus provide clear evidence that species richness has a strong negative effect on root decomposition via effects on both root substrate quality and soil decomposition environment. This negative plant diversity-root decomposition relationship may partly account for the positive effect of plant diversity on soil C stocks by reducing C loss in addition to increasing primary root productivity. However, to fully

  9. Hydrogen production by the decomposition of water

    DOEpatents

    Hollabaugh, Charles M.; Bowman, Melvin G.

    1981-01-01

    How to produce hydrogen from water was a problem addressed by this invention. The solution employs a combined electrolytical-thermochemical sulfuric acid process. Additionally, high purity sulfuric acid can be produced in the process. Water and SO.sub.2 react in electrolyzer (12) so that hydrogen is produced at the cathode and sulfuric acid is produced at the anode. Then the sulfuric acid is reacted with a particular compound M.sub.r X.sub.s so as to form at least one water insoluble sulfate and at least one water insoluble oxide of molybdenum, tungsten, or boron. Water is removed by filtration; and the sulfate is decomposed in the presence of the oxide in sulfate decomposition zone (21), thus forming SO.sub.3 and reforming M.sub.r X.sub.s. The M.sub.r X.sub.s is recycled to sulfate formation zone (16). If desired, the SO.sub.3 can be decomposed to SO.sub.2 and O.sub.2 ; and the SO.sub.2 can be recycled to electrolyzer (12) to provide a cycle for producing hydrogen.

  10. Nutrient-enhanced decomposition of plant biomass in a freshwater wetland

    USGS Publications Warehouse

    Bodker, James E.; Turner, Robert Eugene; Tweel, Andrew; Schulz, Christopher; Swarzenski, Christopher M.

    2015-01-01

    We studied soil decomposition in a Panicum hemitomon (Schultes)-dominated freshwater marsh located in southeastern Louisiana that was unambiguously changed by secondarily-treated municipal wastewater effluent. We used four approaches to evaluate how belowground biomass decomposition rates vary under different nutrient regimes in this marsh. The results of laboratory experiments demonstrated how nutrient enrichment enhanced the loss of soil or plant organic matter by 50%, and increased gas production. An experiment demonstrated that nitrogen, not phosphorus, limited decomposition. Cellulose decomposition at the field site was higher in the flowfield of the introduced secondarily treated sewage water, and the quality of the substrate (% N or % P) was directly related to the decomposition rates. We therefore rejected the null hypothesis that nutrient enrichment had no effect on the decomposition rates of these organic soils. In response to nutrient enrichment, plants respond through biomechanical or structural adaptations that alter the labile characteristics of plant tissue. These adaptations eventually change litter type and quality (where the marsh survives) as the % N content of plant tissue rises and is followed by even higher decomposition rates of the litter produced, creating a positive feedback loop. Marsh fragmentation will increase as a result. The assumptions and conditions underlying the use of unconstrained wastewater flow within natural wetlands, rather than controlled treatment within the confines of constructed wetlands, are revealed in the loss of previously sequestered carbon, habitat, public use, and other societal benefits.

  11. Effect of water level drawdown on decomposition in boreal peatlands

    NASA Astrophysics Data System (ADS)

    Straková, Petra; Penttilä, Timo; Laiho, Raija

    2010-05-01

    Plant litter production and decomposition are key processes in element cycling in most ecosystems. In peatlands, there has been a long-term imbalance between litter production and decay caused by high water levels (WL) and consequent anoxia. This has resulted in peatlands being a significant sink of carbon (C) from the atmosphere. However, peatlands are experiencing both "natural" (global climate change) and anthropogenic (ditching) changes that threaten their ability to retain this ecosystem identity and function. Many of these alterations can be traced back to WL drawdown, which can cause increased aeration, higher acidity, falling temperatures, and a greater probability of drought. Such changes are also associated with an increasing decomposition rate, and therefore a greater amount of C released back to the atmosphere. Yet studies about how the overall C balance of peatlands will be affected have come up with conflicting conclusions, demonstrating that the C store could increase, decrease, or remain static. A factor that has been largely overlooked is the change in litter type composition following persistent WL drawdown. It is the aim of our study, then, to help to resolve this issue. We studied the effects of short-term (ca. 4 years) and long-term (ca. 40 years) persistent WL drawdown on the decomposition of numerous types of above-ground and below-ground plant litters at three boreal peatland sites: bog, oligotrophic fen and mesotrophic fen. We thus believe that enough permutations have been created to obtain a good assessment of how each factor, site nutrient level, WL regime, and litter type composition, influences decomposition. We used the litter bag method to measure the decomposition rates: placed measured amounts of plant litter, or cellulose strips as a control, into closed mesh bags, and installed the bags in the natural environment for decomposition for each litter type for varying amounts of time. Following litter bag recovery, the litter was

  12. Elevated atmospheric carbon dioxide effects on cotton plant residue decomposition

    SciTech Connect

    Torbert, H.A.; Prior, S.A.; Rogers, H.H.

    1995-09-01

    Assessing the impact of elevated atmospheric CO{sub 2} concentration on the global environment is hampered due to a lack of understanding of global C cycling. Carbon fixed within plant biomass ultimately enters the soil via plant residues, but the effects of elevated-CO{sub 2}-grown plant material on decomposition rates and long-term soil C storage are unknown. The objective of this study was to determine the decomposition rate of plant residues grown under an elevated CO{sub 2} environment as affected by soil type. Cotton (Gossypium hirsutum L. `Delta Pine 77`) samples were collected from a free-air CO{sub 2} enrichment (550 {mu}L L{sup -1}) experiment. The plant residues were incubated under ambient CO{sub 2} conditions to determine decomposition rates of leaves, stems, and roots and potential N and P mineralization-immobilization in three soil series. No significant difference was observed between plant residue grown under CO{sub 2} enrichment vs. ambient CO{sub 2} conditions for soil respiration or P mineralization-immobilization. Significantly greater net N immobilization was observed during the incubation in all soil types for plant residue grown at elevated CO{sub 2}. These results indicate that while decomposition of plant residue may not be reduced by CO{sub 2} enrichment, N dynamics may be markedly changed. 32 refs., 5 figs., 3 tabs.

  13. Hydrogen production by the decomposition of water

    DOEpatents

    Hollabaugh, C.M.; Bowman, M.G.

    A process is described for the production of hydrogen from water by a sulfuric acid process employing electrolysis and thermo-chemical decomposition. The water containing SO/sub 2/ is electrolyzed to produce H/sub 2/ at the cathode and to oxidize the SO/sub 2/ to form H/sub 2/SO/sub 4/ at the anode. After the H/sub 2/ has been separated, a compound of the type M/sub r/X/sub s/ is added to produce a water insoluble sulfate of M and a water insoluble oxide of the metal in the radical X. In the compound M/sub r/X/sub s/, M is at least one metal selected from the group consisting of Ba/sup 2 +/, Ca/sup 2 +/, Sr/sup 2 +/, La/sup 2 +/, and Pb/sup 2 +/; X is at least one radical selected from the group consisting of molybdate (MoO/sub 4//sup 2 -/), tungstate (WO/sub 4//sup 2 -/), and metaborate (BO/sub 2//sup 1 -/); and r and s are either 1, 2, or 3 depending upon the valence of M and X. The precipitated mixture is filtered and heated to a temperature sufficiently high to form SO/sub 3/ gas and to reform M/sub r/X/sub s/. The SO/sub 3/ is dissolved in a small amount of H/sub 2/O to produce concentrated H/sub 2/SO/sub 4/, and the M/sub r/X/sub s/ is recycled to the process. Alternatively, the SO/sub 3/ gas can be recycled to the beginning of the process to provide a continuous process for the production of H/sub 2/ in which only water need be added in a substantial amount. (BLM)

  14. Plant litter decomposition in a semi-arid ecosystem controlled by photodegradation.

    PubMed

    Austin, Amy T; Vivanco, Lucía

    2006-08-01

    The carbon balance in terrestrial ecosystems is determined by the difference between inputs from primary production and the return of carbon to the atmosphere through decomposition of organic matter. Our understanding of the factors that control carbon turnover in water-limited ecosystems is limited, however, as studies of litter decomposition have shown contradictory results and only a modest correlation with precipitation. Here we evaluate the influence of solar radiation, soil biotic activity and soil resource availability on litter decomposition in the semi-arid Patagonian steppe using the results of manipulative experiments carried out under ambient conditions of rainfall and temperature. We show that intercepted solar radiation was the only factor that had a significant effect on the decomposition of organic matter, with attenuation of ultraviolet-B and total radiation causing a 33 and 60 per cent reduction in decomposition, respectively. We conclude that photodegradation is a dominant control on above-ground litter decomposition in this semi-arid ecosystem. Losses through photochemical mineralization may represent a short-circuit in the carbon cycle, with a substantial fraction of carbon fixed in plant biomass being lost directly to the atmosphere without cycling through soil organic matter pools. Furthermore, future changes in radiation interception due to decreased cloudiness, increased stratospheric ozone depletion, or reduced vegetative cover may have a more significant effect on the carbon balance in these water-limited ecosystems than changes in temperature or precipitation. PMID:16885982

  15. Does Accelerated Soil Organic Matter Decomposition in the Presence of Plants Increase Plant N Availability?

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Plant roots can increase microbial activity and soil organic matter (SOM) decomposition via rhizosphere priming effects. It is virtually unknown how differences in the priming effect among plant species and soil type affect N mineralization and plant uptake. In a greenhouse experiment, we tested whe...

  16. Thermal decomposition of substituted phenols in supercritical water

    SciTech Connect

    Martino, C.J.; Savage, P.E.

    1997-05-01

    The thermal decomposition of cresols, hydroxybenzaldehydes, nitrophenols, and benzenediols was studied in dilute aqueous solutions and in the absence of oxygen at 460 C and 250 atm for residence times around 10 s. Thermolysis under these conditions produced conversions of less than 10% for o-, m-, and p-cresol, whereas hydroxybenzaldehydes and nitrophenols were much more reactive. Global rate expressions are reported for the thermolysis of each hydroxybenzaldehyde and nitrophenol isomer. Phenol was a major product from the decomposition of all of the substituted phenols studied. For a given substituent, ortho-substituted phenols reacted more rapidly than the other isomers. For a given substituted position, nitrophenols reacted more rapidly than hydroxybenzaldehydes, which in turn reacted more rapidly than cresols. These results demonstrate that the treatment of CHO- and NO{sub 2}-substituted phenols by oxidation in supercritical water will involve the oxidation of thermal decomposition products in addition to the oxidation of the original compounds.

  17. Method for thermochemical decomposition of water

    DOEpatents

    Abraham, Bernard M.; Schreiner, Felix

    1977-01-11

    Water is thermochemically decomposed to produce hydrogen by the following sequence of reactions: KI, NH.sub.3, CO.sub. 2 and water in an organic solvent such as ethyl or propyl alcohol are reacted to produce KHCO 3 and NH.sub.4 I. The KHCO.sub.3 is thermally decomposed to K.sub.2 CO.sub.3, H.sub.2 O and CO.sub.2, while the NH.sub.4 I is reacted with Hg to produce HgI.sub.2, NH.sub.3 and H.sub.2. The K.sub.2 CO.sub.3 obtained by calcining KHCO.sub.3 is then reacted with HgI.sub.2 to produce Hg, KI, CO and O.sub.2. All products of the reaction are recycled except hydrogen and oxygen.

  18. Earthworms and legumes control litter decomposition in a plant diversity gradient.

    PubMed

    Milcu, Alexandru; Partsch, Stephan; Scherber, Christoph; Weisser, Wolfgang W; Scheu, Stefan

    2008-07-01

    The role of species and functional group diversity of primary producers for decomposers and decomposition processes is little understood. We made use of the "Jena Biodiversity Experiment" and tested the hypothesis that increasing plant species (1, 4, and 16 species) and functional group diversity (1, 2, 3, and 4 groups) beneficially affects decomposer density and activity and therefore the decomposition of plant litter material. Furthermore, by manipulating the densities of decomposers (earthworms and springtails) within the plant diversity gradient we investigated how the interactions between plant diversity and decomposer densities affect the decomposition of litter belonging to different plant functional groups (grasses, herbs, and legumes). Positive effects of increasing plant species or functional group diversity on earthworms (biomass and density) and microbial biomass were mainly due to the increased incidence of legumes with increasing diversity. Neither plant species diversity nor functional group diversity affected litter decomposition, However, litter decomposition varied with decomposer and plant functional group identity (of both living plants and plant litter). While springtail removal generally had little effect on decomposition, increased earthworm density accelerated the decomposition of nitrogen-rich legume litter, and this was more pronounced at higher plant diversity. The results suggest that earthworms (Lumbricus terrestris L.) and legumes function as keystone organisms for grassland decomposition processes and presumably contribute to the recorded increase in primary productivity with increasing plant diversity. PMID:18705374

  19. Decomposition

    USGS Publications Warehouse

    Middleton, Beth A.

    2014-01-01

    A cornerstone of ecosystem ecology, decomposition was recognized as a fundamental process driving the exchange of energy in ecosystems by early ecologists such as Lindeman 1942 and Odum 1960). In the history of ecology, studies of decomposition were incorporated into the International Biological Program in the 1960s to compare the nature of organic matter breakdown in various ecosystem types. Such studies still have an important role in ecological studies of today. More recent refinements have brought debates on the relative role microbes, invertebrates and environment in the breakdown and release of carbon into the atmosphere, as well as how nutrient cycling, production and other ecosystem processes regulated by decomposition may shift with climate change. Therefore, this bibliography examines the primary literature related to organic matter breakdown, but it also explores topics in which decomposition plays a key supporting role including vegetation composition, latitudinal gradients, altered ecosystems, anthropogenic impacts, carbon storage, and climate change models. Knowledge of these topics is relevant to both the study of ecosystem ecology as well projections of future conditions for human societies.

  20. Plant Water Relations.

    ERIC Educational Resources Information Center

    Tomley, David

    1982-01-01

    Some simple field investigations on plant water relations are described which demonstrate links between physiological and external environmental factors. In this way, a more complex picture of a plant and how it functions within its habitat and the effects the environment has on it can be built up. (Author/JN)

  1. Decomposition of cellulose by ultrasonic welding in water

    NASA Astrophysics Data System (ADS)

    Nomura, Shinfuku; Miyagawa, Seiya; Mukasa, Shinobu; Toyota, Hiromichi

    2016-07-01

    The use of ultrasonic welding in water to decompose cellulose placed in water was examined experimentally. Filter paper was used as the decomposition material with a horn-type transducer 19.5 kHz adopted as the ultrasonic welding power source. The frictional heat at the point where the surface of the tip of the ultrasonic horn contacts the filter paper decomposes the cellulose in the filter paper into 5-hydroxymethylfurfural (5-HMF), furfural, and oligosaccharide through hydrolysis and thermolysis that occurs in the welding process.

  2. Stoichiometry of Microbial Decomposition Priming in Plant Litter and Soil

    NASA Astrophysics Data System (ADS)

    Schaefer, D.; Qiao, N.

    2011-12-01

    Microbial priming is accelerated conversion of plant residues and soil organic carbon to CO2. It is caused by small additions of labile carbon and nitrogen compounds, but microbial stoichiometry suggests that this description is incomplete. The temperature dependence of soil organic carbon cycling models may be related to diffusion of labile resources to microbial cells. Incomplete treatment of stoichiometrically significant elements in these models may also limit their ability to predict carbon fluxes if plant species, diseases or defoliators are affected by climate changes. We explore this by incubating decomposable substrates (leaves, wood, humus and mineral soil) with resources added as dissolved inorganic nitrogen (ammonium and nitrate separately), phosphorus and sugar, added in different amounts and proportions. We measure CO2 production by infrared absorption. Contribution of sugar to CO2 production is assessed by mass spectrometry. High concentrations for each resource are 16X the low, and middle concentrations are 4X the low. The ratios are centered on 200:10:1. We explore C:N:P resource ratios and additions over wide ranges; subsequently to examine narrower ranges of interest. For C:N:P incubations, C and N effects are always significant on CO2 production, with P in only half of the treatments. Literature suggests that leaf-litter decomposition is stimulated by N (occasionally P) additions, but results for soils have been mixed. We find N to be inhibitory only when added in "stoichiometic excess" to added C. Stimulation of microbial respiration is generally strongest with C:N:P additions in "Redfield-like" ratios, but the response is far below linear. Humus has a stronger response to C than do leaves and wood. This is consistent with a chronic energy limitation for soil microbes, even where their environments contain large amounts of total C. For all substrates, the addition of N as nitrate leads to significantly more CO2 than the same amount of ammonium

  3. PCB decomposition and formation in thermal treatment plant equipment.

    PubMed

    Ishikawa, Yukari; Noma, Yukio; Yamamoto, Takashi; Mori, Yoshihito; Sakai, Shin-ichi

    2007-04-01

    In this study we investigated both the decomposition and unintentional formation of polychlorinated biphenyl congeners during combustion experiments of refuse-derived fuel (RDF) and automobile shredder residue (ASR) at several stages in thermal treatment plant equipment composed of a primary combustion chamber, a secondary combustion chamber, and other equipments for flue gas treatment. In both experiments, the unintentional formation of PCB occurred in the primary combustion chamber at the same time as the decomposition of PCB in input samples. By combusting RDF, non-ortho-PCB predominantly formed, whereas ortho-PCB and symmetric chlorinated biphenyls (e.g., #52/69, #87/108, and #151) tended to be decomposed. ASR formed the higher chlorinated biphenyls more than RDF. These by-products from ASR had no structural relation with ortho-chlorine. Lower chlorinated biphenyls appeared as predominant homologues at the final exit site, while all congeners from lower to higher chlorinated PCB were unintentionally formed as by-products in the primary combustion chamber. This result showed that the flue gas treatment equipments effectively removed higher chlorinated PCB. Input marker congeners of RDF were #11, #39, and #68, while those for ASR were #11, #101, #110/120, and #118. Otherwise, combustion marker congeners of RDF were #13/12, #35, #77, and #126, while those for ASR were #170, #194, #206, and #209. While the concentration of PCB increased significantly in the primary combustion chamber, the value of toxicity equivalency quantity for dioxin-like PCB decreased in the secondary combustion chamber and the flue gas treatment equipments. PMID:17134732

  4. Effects of hydrology on short term plant decomposition and nutrient content in a re-created Everglades wetland

    NASA Astrophysics Data System (ADS)

    Serna, A.; Richards, J.; Scinto, L.

    2012-12-01

    The effect of water depth and flow on tissue nutrients and decomposition rates of marsh plant species, and soil chemistry in vegetated plots was measured in the Loxahatchee Impoundment Landscape Assessment (LILA) facility in Boynton Beach, Florida, USA. The LILA facility consists of replicated wetland macrocosms that mimic Everglades ridge-and-slough landscape features. The experiments were conducted in two macrocosms that each had three habitats at different water depths (ridge, shallow slough and deep slough) but differed in flow. Decomposition rates of three common Everglades species, Cladium jamaicense (sawgrass), Eleocharis cellulosa (spikerush), and Nymphaea odorata (white water lily), were measured using litter bags incubated during both a wet and dry condition. Litter bag losses were more pronounced under wet conditions, and decomposition rates were not affected by the hydrologic conditions in this experiment, but rather by litter nutrient content and species. Litter nutrient (TC, TN, TP) concentrations varied over time. Species rich in the limiting nutrient (P) in the ecosystem decomposed faster. Therefore, N. odorata decomposed faster than C. jamaicense and E. cellulosa, confirming the importance of P availability in controlling microbial processes in the Everglades. Planted species had no effect on soil nutrient content over the 3 yrs period of plant growth in these plots. Our results have contributed to defining potential flow targets for restoration in Florida's Everglades by showing that average water velocities of 0.5 cm s-1 may not be sufficient to drive ecosystem changes in decomposition rates for the native species and soil chemistry.

  5. Hydrogen production by water decomposition using a combined electrolytic-thermochemical cycle

    NASA Technical Reports Server (NTRS)

    Farbman, G. H.; Brecher, L. E.

    1976-01-01

    A proposed dual-purpose power plant generating nuclear power to provide energy for driving a water decomposition system is described. The entire system, dubbed Sulfur Cycle Water Decomposition System, works on sulfur compounds (sulfuric acid feedstock, sulfur oxides) in a hybrid electrolytic-thermochemical cycle; performance superior to either all-electrolysis systems or presently known all-thermochemical systems is claimed. The 3345 MW(th) graphite-moderated helium-cooled reactor (VHTR - Very High Temperature Reactor) generates both high-temperature heat and electric power for the process; the gas stream at core exit is heated to 1850 F. Reactor operation is described and reactor innards are illustrated. A cost assessment for on-stream performance in the 1990's is optimistic.

  6. Adiabatic calorimetric decomposition studies of 50 wt.% hydroxylamine/water.

    PubMed

    Cisneros, L O; Rogers, W J; Mannan, M S

    2001-03-19

    Calorimetric data can provide a basis for determining potential hazards in reactions, storage, and transportation of process chemicals. This work provides calorimetric data for the thermal decomposition behavior in air of 50wt.% hydroxylamine/water (HA), both with and without added stabilizers, which was measured in closed cells with an automatic pressure tracking adiabatic calorimeter (APTAC). Among the data provided are onset temperatures, reaction order, activation energies, pressures of noncondensable products, thermal stability at 100 degrees C, and the effect of HA storage time. Discussed also are the catalytic effects of carbon steel, stainless steel, stainless steel with silica coating, inconel, titanium, and titanium with silica coating on the reaction self-heat rates and onset temperatures. In borosilicate glass cells, HA was relatively stable at temperatures up to 133 degrees C, where the HA decomposition self-heat rate reached 0.05 degrees C/min. The added stabilizers appeared to reduce HA decomposition rates in glass cells and at ambient temperatures. The tested metals and metal surfaces coated with silica acted as catalysts to lower the onset temperatures and increase the self-heat rates. PMID:11165058

  7. Hydroxyl radicals from secondary organic aerosol decomposition in water

    NASA Astrophysics Data System (ADS)

    Tong, Haijie; Arangio, Andrea M.; Lakey, Pascale S. J.; Berkemeier, Thomas; Liu, Fobang; Kampf, Christopher J.; Brune, William H.; Pöschl, Ulrich; Shiraiwa, Manabu

    2016-02-01

    We found that ambient and laboratory-generated secondary organic aerosols (SOA) form substantial amounts of OH radicals upon interaction with liquid water, which can be explained by the decomposition of organic hydroperoxides. The molar OH yield from SOA formed by ozonolysis of terpenes (α-pinene, β-pinene, limonene) is ˜ 0.1 % upon extraction with pure water and increases to ˜ 1.5 % in the presence of Fe2+ ions due to Fenton-like reactions. Upon extraction of SOA samples from OH photooxidation of isoprene, we also detected OH yields of around ˜ 0.1 %, which increases upon addition of Fe2+. Our findings imply that the chemical reactivity and aging of SOA particles is strongly enhanced upon interaction with water and iron. In cloud droplets under dark conditions, SOA decomposition can compete with the classical H2O2 Fenton reaction as the source of OH radicals. Also in the human respiratory tract, the inhalation and deposition of SOA particles may lead to a substantial release of OH radicals, which may contribute to oxidative stress and play an important role in the adverse health effects of atmospheric aerosols.

  8. Hydroxyl radicals from secondary organic aerosol decomposition in water

    NASA Astrophysics Data System (ADS)

    Tong, H.; Arangio, A. M.; Lakey, P. S. J.; Berkemeier, T.; Liu, F.; Kampf, C. J.; Pöschl, U.; Shiraiwa, M.

    2015-11-01

    We found that ambient and laboratory-generated secondary organic aerosols (SOA) form substantial amounts of OH radicals upon interaction with liquid water, which can be explained by the decomposition of organic hydroperoxides. The molar OH yield from SOA formed by ozonolysis of terpenes (α-pinene, β-pinene, limonene) is ~ 0.1 % upon extraction with pure water and increases to ~ 1.5 % in the presence of Fe2+ ions due to Fenton-like reactions. Our findings imply that the chemical reactivity and aging of SOA particles is strongly enhanced upon interaction with water and iron. In cloud droplets under dark conditions, SOA decomposition can compete with the classical H2O2 Fenton reaction as the source of OH radicals. Also in the human respiratory tract, the inhalation and deposition of SOA particles may lead to a substantial release of OH radicals, which may contribute to oxidative stress and play an important role in the adverse health effects of atmospheric aerosols.

  9. Hydroxyl radicals from secondary organic aerosol decomposition in water

    NASA Astrophysics Data System (ADS)

    Tong, Haijie; Arangio, Andrea M.; Lakey, Pascale S. J.; Berkemeier, Thomas; Liu, Fobang; Kampf, Christopher. J.; Pöschl, Ulrich; Shiraiwa, Manabu

    2016-04-01

    We found that ambient and laboratory-generated secondary organic aerosols (SOA) form substantial amounts of OH radicals upon interaction with liquid water, which can be explained by the decomposition of organic hydroperoxides. The molar OH yield from SOA formed by ozonolysis of terpenes (α-pinene, β-pinene, and limonene) is ~ 0.1% upon extraction with pure water, and which increases to ~ 1.5% in the presence of iron ions due to Fenton-like reactions. Our findings imply that the chemical reactivity and aging of SOA particles is strongly enhanced upon interaction with water and iron. In cloud droplets under dark conditions, SOA decomposition can compete with the classical hydrogen peroxide Fenton reaction as the source of OH radicals. Also in the human respiratory tract, the inhalation and deposition of SOA particles may lead to a substantial release of OH radicals, which may contribute to oxidative stress and play an important role in the adverse health effects of atmospheric aerosols.

  10. Elevated CO2 and plant species diversity interact to slow root decomposition

    SciTech Connect

    De Graaff, Marie-Anne; Schadt, Christopher Warren; Rula, Kelly L; Six, Johan W U A; Schweitzer, Jennifer A; Classen, Aimee T

    2011-01-01

    Changes in plant species diversity can result in synergistic increases in decomposition rates, while elevated atmospheric CO2 can slow the decomposition rates; yet it remains unclear how diversity and changes in atmospheric CO2 may interact to alter root decomposition. To investigate how elevated CO2 interacts with changes in root-litter diversity to alter decomposition rates, we conducted a 120-day laboratory incubation. Roots from three species (Trifolium repens, Lespedeza cuneata, and Festuca pratense) grown under ambient or elevated CO2 were incubated individually or in combination in soils that were exposed to ambient or elevated CO2 for five years. Our experiment resulted in two main findings: (1) Roots from T. repens and L. cuneata, both nitrogen (N) fixers, grown under elevated CO2 treatments had significantly slower decomposition rates than similar roots grown under ambient CO2 treatments; but the decomposition rate of F. pratense roots (a non-N-fixing species) was similar regardless of CO2 treatment. (2) Roots of the three species grown under ambient CO2 and decomposed in combination with each other had faster decomposition rates than when they were decomposed as single species. However, roots of the three species grown under elevated CO2 had similar decomposition rates when they were incubated alone or in combination with other species. These data suggest that if elevated CO2 reduces the root decomposition rate of even a few species in the community, it may slow root decomposition of the entire plant community.

  11. Plant-derived compounds stimulate the decomposition of organic matter in arctic permafrost soils.

    PubMed

    Wild, Birgit; Gentsch, Norman; Čapek, Petr; Diáková, Kateřina; Alves, Ricardo J Eloy; Bárta, Jiři; Gittel, Antje; Hugelius, Gustaf; Knoltsch, Anna; Kuhry, Peter; Lashchinskiy, Nikolay; Mikutta, Robert; Palmtag, Juri; Schleper, Christa; Schnecker, Jörg; Shibistova, Olga; Takriti, Mounir; Torsvik, Vigdis L; Urich, Tim; Watzka, Margarete; Šantrůčková, Hana; Guggenberger, Georg; Richter, Andreas

    2016-01-01

    Arctic ecosystems are warming rapidly, which is expected to promote soil organic matter (SOM) decomposition. In addition to the direct warming effect, decomposition can also be indirectly stimulated via increased plant productivity and plant-soil C allocation, and this so called "priming effect" might significantly alter the ecosystem C balance. In this study, we provide first mechanistic insights into the susceptibility of SOM decomposition in arctic permafrost soils to priming. By comparing 119 soils from four locations across the Siberian Arctic that cover all horizons of active layer and upper permafrost, we found that an increased availability of plant-derived organic C particularly stimulated decomposition in subsoil horizons where most of the arctic soil carbon is located. Considering the 1,035 Pg of arctic soil carbon, such an additional stimulation of decomposition beyond the direct temperature effect can accelerate net ecosystem C losses, and amplify the positive feedback to global warming. PMID:27157964

  12. Plant-derived compounds stimulate the decomposition of organic matter in arctic permafrost soils

    PubMed Central

    Wild, Birgit; Gentsch, Norman; Čapek, Petr; Diáková, Kateřina; Alves, Ricardo J. Eloy; Bárta, Jiři; Gittel, Antje; Hugelius, Gustaf; Knoltsch, Anna; Kuhry, Peter; Lashchinskiy, Nikolay; Mikutta, Robert; Palmtag, Juri; Schleper, Christa; Schnecker, Jörg; Shibistova, Olga; Takriti, Mounir; Torsvik, Vigdis L.; Urich, Tim; Watzka, Margarete; Šantrůčková, Hana; Guggenberger, Georg; Richter, Andreas

    2016-01-01

    Arctic ecosystems are warming rapidly, which is expected to promote soil organic matter (SOM) decomposition. In addition to the direct warming effect, decomposition can also be indirectly stimulated via increased plant productivity and plant-soil C allocation, and this so called “priming effect” might significantly alter the ecosystem C balance. In this study, we provide first mechanistic insights into the susceptibility of SOM decomposition in arctic permafrost soils to priming. By comparing 119 soils from four locations across the Siberian Arctic that cover all horizons of active layer and upper permafrost, we found that an increased availability of plant-derived organic C particularly stimulated decomposition in subsoil horizons where most of the arctic soil carbon is located. Considering the 1,035 Pg of arctic soil carbon, such an additional stimulation of decomposition beyond the direct temperature effect can accelerate net ecosystem C losses, and amplify the positive feedback to global warming. PMID:27157964

  13. Plant-derived compounds stimulate the decomposition of organic matter in arctic permafrost soils

    NASA Astrophysics Data System (ADS)

    Wild, Birgit; Gentsch, Norman; Čapek, Petr; Diáková, Kateřina; Alves, Ricardo J. Eloy; Bárta, Jiři; Gittel, Antje; Hugelius, Gustaf; Knoltsch, Anna; Kuhry, Peter; Lashchinskiy, Nikolay; Mikutta, Robert; Palmtag, Juri; Schleper, Christa; Schnecker, Jörg; Shibistova, Olga; Takriti, Mounir; Torsvik, Vigdis L.; Urich, Tim; Watzka, Margarete; Šantrůčková, Hana; Guggenberger, Georg; Richter, Andreas

    2016-05-01

    Arctic ecosystems are warming rapidly, which is expected to promote soil organic matter (SOM) decomposition. In addition to the direct warming effect, decomposition can also be indirectly stimulated via increased plant productivity and plant-soil C allocation, and this so called “priming effect” might significantly alter the ecosystem C balance. In this study, we provide first mechanistic insights into the susceptibility of SOM decomposition in arctic permafrost soils to priming. By comparing 119 soils from four locations across the Siberian Arctic that cover all horizons of active layer and upper permafrost, we found that an increased availability of plant-derived organic C particularly stimulated decomposition in subsoil horizons where most of the arctic soil carbon is located. Considering the 1,035 Pg of arctic soil carbon, such an additional stimulation of decomposition beyond the direct temperature effect can accelerate net ecosystem C losses, and amplify the positive feedback to global warming.

  14. Experimental study of hydrogen production by direct decomposition of water

    NASA Astrophysics Data System (ADS)

    Bilgen, E.; Galindo, J.; Baykara, S. Z.

    The hydrogen production by direct decomposition of water in a solar furnace is studied. The set-up is a horizontal axis system consisting of two 1.0 kW parabolic concentrators, both powered by a single heliostat. A temperature of 3000 K is possible. The water is fed to the reactor installed at the focal space of the concentrator, and the steam is decomposed at about 2500 K. The reactor consisted of a cylindrical cavity type refractory receiver covered with a silica cupola. The steam was introduced at a known rate into the cavity and the product gases were quenched. After the condensation of steam, hydrogen and oxygen were collected in a reservoir. Results indicate that with an optimized system, it is possible to produce hydrogen at about 70 percent rate of the theoretical value at the temperature level studied.

  15. Soil organic matter decomposition follows plant productivity response to sea-level rise

    NASA Astrophysics Data System (ADS)

    Mueller, Peter; Jensen, Kai; Megonigal, James Patrick

    2015-04-01

    The accumulation of soil organic matter (SOM) is an important mechanism for many tidal wetlands to keep pace with sea-level rise. SOM accumulation is governed by the rates of production and decomposition of organic matter. While plant productivity responses to sea-level rise are well understood, far less is known about the response of SOM decomposition to accelerated sea-level rise. Here we quantified the effects of sea-level rise on SOM decomposition by exposing planted and unplanted tidal marsh monoliths to experimentally manipulated flood duration. The study was performed in a field-based mesocosm facility at the Smithsonian Global Change Research Wetland, a micro tidal brackish marsh in Maryland, US. SOM decomposition was quantified as CO2 efflux, with plant- and SOM-derived CO2 separated using a stable carbon isotope approach. Despite the dogma that decomposition rates are inversely related to flooding, SOM mineralization was not sensitive to varying flood duration over a 35 cm range in surface elevation in unplanted mesocoms. In the presence of plants, decomposition rates were strongly and positively related to aboveground biomass (p≤0.01, R2≥0.59). We conclude that rates of soil carbon loss through decomposition are driven by plant responses to sea level in this intensively studied tidal marsh. If our result applies more generally to tidal wetlands, it has important implications for modeling carbon sequestration and marsh accretion in response to accelerated sea-level rise.

  16. Plants mediate soil organic matter decomposition in response to sea level rise.

    PubMed

    Mueller, Peter; Jensen, Kai; Megonigal, James Patrick

    2016-01-01

    Tidal marshes have a large capacity for producing and storing organic matter, making their role in the global carbon budget disproportionate to land area. Most of the organic matter stored in these systems is in soils where it contributes 2-5 times more to surface accretion than an equal mass of minerals. Soil organic matter (SOM) sequestration is the primary process by which tidal marshes become perched high in the tidal frame, decreasing their vulnerability to accelerated relative sea level rise (RSLR). Plant growth responses to RSLR are well understood and represented in century-scale forecast models of soil surface elevation change. We understand far less about the response of SOM decomposition to accelerated RSLR. Here we quantified the effects of flooding depth and duration on SOM decomposition by exposing planted and unplanted field-based mesocosms to experimentally manipulated relative sea level over two consecutive growing seasons. SOM decomposition was quantified as CO2 efflux, with plant- and SOM-derived CO2 separated via δ(13) CO2 . Despite the dominant paradigm that decomposition rates are inversely related to flooding, SOM decomposition in the absence of plants was not sensitive to flooding depth and duration. The presence of plants had a dramatic effect on SOM decomposition, increasing SOM-derived CO2 flux by up to 267% and 125% (in 2012 and 2013, respectively) compared to unplanted controls in the two growing seasons. Furthermore, plant stimulation of SOM decomposition was strongly and positively related to plant biomass and in particular aboveground biomass. We conclude that SOM decomposition rates are not directly driven by relative sea level and its effect on oxygen diffusion through soil, but indirectly by plant responses to relative sea level. If this result applies more generally to tidal wetlands, it has important implications for models of SOM accumulation and surface elevation change in response to accelerated RSLR. PMID:26342160

  17. Legume presence reduces the decomposition rate of non-legume roots, role of plant traits?

    NASA Astrophysics Data System (ADS)

    De Deyn, Gerlinde B.; Saar, Sirgi; Barel, Janna; Semchenko, Marina

    2016-04-01

    Plant litter traits are known to play an important role in the rate of litter decomposition and mineralization, both for aboveground and belowground litter. However also the biotic and abiotic environment in which the litter decomposes plays a significant role in the rate of decomposition. The presence of living plants may accelerate litter decomposition rates via a priming effects. The size of this effect is expected to be related to the traits of the litter. In this study we focus on root litter, given that roots and their link to ecosystem processes have received relatively little attention in trait-based research. To test the effect of a growing legume plant on root decomposition and the role of root traits in this we used dead roots of 7 different grassland species (comprising grasses, a forb and legumes), determined their C, N, P content and quantified litter mass loss after eight weeks of incubation in soil with and without white clover. We expected faster root decomposition with white clover, especially for root litter with low N content. In contrast we found slower decomposition of grass and forb roots which were poor in N (negative priming) in presence of white clover, while decomposition rates of legume roots were not affected by the presence of white clover. Overall we found that root decomposition can be slowed down in the presence of a living plant and that this effect depends on the traits of the decomposing roots, with a pronounced reduction in root litter poor in N and P, but not in the relatively nutrient-rich legume root litters. The negative priming effect of legume plants on non-legume litter decomposition may have resulted from preferential substrate utilisation by soil microbes.

  18. Plant roots alter microbial potential for mediation of soil organic carbon decomposition

    NASA Astrophysics Data System (ADS)

    Firestone, M.; Shi, S.; Herman, D.; He, Z.; Zhou, J.

    2014-12-01

    Plant root regulation of soil organic carbon (SOC) decomposition is a key controller of terrestrial C-cycling. Although many studies have tested possible mechanisms underlying plant "priming" of decomposition, few have investigated the microbial mediators of decomposition, which can be greatly influenced by plant activities. Here we examined effects of Avena fatua roots on decomposition of 13C-labeled root litter in a California grassland soil over two simulated growing-seasons. The presence of plant roots consistently suppressed rates of litter decomposition. Reduction of inorganic nitrogen (N) concentration in soil reduced but did not completely relieve this suppressive effect. The presence of plants significantly altered the abundance, composition and functional potential of microbial communities. Significantly higher signal intensities of genes capable of degrading low molecular weight organic compounds (e.g., glucose, formate and malate) were observed in microbial communities from planted soils, while microorganisms in unplanted soils had higher relative abundances of genes involved in degradation of some macromolecules (e.g., hemicellulose and lignin). Additionally, compared to unplanted soils, microbial communities from planted soils had higher signal intensities of proV and proW, suggesting microbial osmotic stress in planted soils. Possible mechanisms for the observed inhibition of decomposition are 1) microbes preferentially using simple substrates from root exudates and 2) soil drying by plant evapotranspiration impairing microbial activity. We propose a simple data-based model suggesting that the impacts of roots, the soil environment, and microbial community composition on decomposition processes result from impacts of these factors on the soil microbial functional gene potential.

  19. Properties of Soil Pore Space Regulate Pathways of Plant Residue Decomposition and Community Structure of Associated Bacteria

    PubMed Central

    Negassa, Wakene C.; Guber, Andrey K.; Kravchenko, Alexandra N.; Marsh, Terence L.; Hildebrandt, Britton; Rivers, Mark L.

    2015-01-01

    Physical protection of soil carbon (C) is one of the important components of C storage. However, its exact mechanisms are still not sufficiently lucid. The goal of this study was to explore the influence of soil structure, that is, soil pore spatial arrangements, with and without presence of plant residue on (i) decomposition of added plant residue, (ii) CO2 emission from soil, and (iii) structure of soil bacterial communities. The study consisted of several soil incubation experiments with samples of contrasting pore characteristics with/without plant residue, accompanied by X-ray micro-tomographic analyses of soil pores and by microbial community analysis of amplified 16S–18S rRNA genes via pyrosequencing. We observed that in the samples with substantial presence of air-filled well-connected large (>30 µm) pores, 75–80% of the added plant residue was decomposed, cumulative CO2 emission constituted 1,200 µm C g-1 soil, and movement of C from decomposing plant residue into adjacent soil was insignificant. In the samples with greater abundance of water-filled small pores, 60% of the added plant residue was decomposed, cumulative CO2 emission constituted 2,000 µm C g-1 soil, and the movement of residue C into adjacent soil was substantial. In the absence of plant residue the influence of pore characteristics on CO2 emission, that is on decomposition of the native soil organic C, was negligible. The microbial communities on the plant residue in the samples with large pores had more microbial groups known to be cellulose decomposers, that is, Bacteroidetes, Proteobacteria, Actinobacteria, and Firmicutes, while a number of oligotrophic Acidobacteria groups were more abundant on the plant residue from the samples with small pores. This study provides the first experimental evidence that characteristics of soil pores and their air/water flow status determine the phylogenetic composition of the local microbial community and directions and magnitudes of soil C

  20. Properties of soil pore space regulate pathways of plant residue decomposition and community structure of associated bacteria.

    PubMed

    Negassa, Wakene C; Guber, Andrey K; Kravchenko, Alexandra N; Marsh, Terence L; Hildebrandt, Britton; Rivers, Mark L

    2015-01-01

    Physical protection of soil carbon (C) is one of the important components of C storage. However, its exact mechanisms are still not sufficiently lucid. The goal of this study was to explore the influence of soil structure, that is, soil pore spatial arrangements, with and without presence of plant residue on (i) decomposition of added plant residue, (ii) CO2 emission from soil, and (iii) structure of soil bacterial communities. The study consisted of several soil incubation experiments with samples of contrasting pore characteristics with/without plant residue, accompanied by X-ray micro-tomographic analyses of soil pores and by microbial community analysis of amplified 16S-18S rRNA genes via pyrosequencing. We observed that in the samples with substantial presence of air-filled well-connected large (>30 µm) pores, 75-80% of the added plant residue was decomposed, cumulative CO2 emission constituted 1,200 µm C g(-1) soil, and movement of C from decomposing plant residue into adjacent soil was insignificant. In the samples with greater abundance of water-filled small pores, 60% of the added plant residue was decomposed, cumulative CO2 emission constituted 2,000 µm C g(-1) soil, and the movement of residue C into adjacent soil was substantial. In the absence of plant residue the influence of pore characteristics on CO2 emission, that is on decomposition of the native soil organic C, was negligible. The microbial communities on the plant residue in the samples with large pores had more microbial groups known to be cellulose decomposers, that is, Bacteroidetes, Proteobacteria, Actinobacteria, and Firmicutes, while a number of oligotrophic Acidobacteria groups were more abundant on the plant residue from the samples with small pores. This study provides the first experimental evidence that characteristics of soil pores and their air/water flow status determine the phylogenetic composition of the local microbial community and directions and magnitudes of soil C

  1. Properties of soil pore space regulate pathways of plant residue decomposition and community structure of associated bacteria

    SciTech Connect

    Negassa, Wakene C.; Guber, Andrey K.; Kravchenko, Alexandra N.; Marsh, Terence L.; Hildebrandt, Britton; Rivers, Mark L.

    2015-07-01

    Physical protection of soil carbon (C) is one of the important components of C storage. However, its exact mechanisms are still not sufficiently lucid. The goal of this study was to explore the influence of soil structure, that is, soil pore spatial arrangements, with and without presence of plant residue on (i) decomposition of added plant residue, (ii) CO₂ emission from soil, and (iii) structure of soil bacterial communities. The study consisted of several soil incubation experiments with samples of contrasting pore characteristics with/without plant residue, accompanied by X-ray micro-tomographic analyses of soil pores and by microbial community analysis of amplified 16S–18S rRNA genes via pyrosequencing. We observed that in the samples with substantial presence of air-filled well-connected large (>30 µm) pores, 75–80% of the added plant residue was decomposed, cumulative CO₂ emission constituted 1,200 µm C g⁻¹ soil, and movement of C from decomposing plant residue into adjacent soil was insignificant. In the samples with greater abundance of water-filled small pores, 60% of the added plant residue was decomposed, cumulative CO₂ emission constituted 2,000 µm C g⁻¹ soil, and the movement of residue C into adjacent soil was substantial. In the absence of plant residue the influence of pore characteristics on CO₂ emission, that is on decomposition of the native soil organic C, was negligible. The microbial communities on the plant residue in the samples with large pores had more microbial groups known to be cellulose decomposers, that is, Bacteroidetes, Proteobacteria, Actinobacteria, and Firmicutes, while a number of oligotrophic Acidobacteria groups were more abundant on the plant residue from the samples with small pores. This study provides the first experimental evidence that characteristics of soil pores and their air/water flow status determine the phylogenetic composition of the local microbial community and directions and magnitudes of

  2. Labile soil carbon inputs mediate the soil microbial community composition and plant residue decomposition rates

    SciTech Connect

    De Graaff, Marie-Anne; Classen, Aimee T; Castro Gonzalez, Hector F; Schadt, Christopher Warren

    2010-01-01

    Root carbon (C) inputs may regulate decomposition rates in soil, and in this study we ask: how do labile C inputs regulate decomposition of plant residues, and soil microbial communities? In a 14 d laboratory incubation, we added C compounds often found in root exudates in seven different concentrations (0, 0.7, 1.4, 3.6, 7.2, 14.4 and 21.7 mg C g{sup -1} soil) to soils amended with and without {sup 13}C-labeled plant residue. We measured CO{sub 2} respiration and shifts in relative fungal and bacterial rRNA gene copy numbers using quantitative polymerase chain reaction (qPCR). Increased labile C input enhanced total C respiration, but only addition of C at low concentrations (0.7 mg C g{sup -1}) stimulated plant residue decomposition (+2%). Intermediate concentrations (1.4, 3.6 mg C g{sup -1}) had no impact on plant residue decomposition, while greater concentrations of C (> 7.2 mg C g{sup -1}) reduced decomposition (-50%). Concurrently, high exudate concentrations (> 3.6 mg C g{sup -1}) increased fungal and bacterial gene copy numbers, whereas low exudate concentrations (< 3.6 mg C g{sup -1}) increased metabolic activity rather than gene copy numbers. These results underscore that labile soil C inputs can regulate decomposition of more recalcitrant soil C by controlling the activity and relative abundance of fungi and bacteria.

  3. Manganese Cycling in a Long-term Plant Litter Decomposition Time Series

    NASA Astrophysics Data System (ADS)

    Keiluweit, M.; Nico, P. S.; Kleber, M.; Bougoure, J.; Harmon, M. E.; Pett-Ridge, J.

    2012-12-01

    Climate change is predicted to affect the chemical composition of plant litter, and global warming may increase microbial and enzymatic activity, with uncertain consequences for litter decomposition rates in soils. This uncertainty has highlighted the need to better understand the controls on litter decomposition rates and pathways. A key controlling processes that is poorly understood is the coupling between decomposition pathways and the inorganic resources available in fresh litter or the underlying soil. For example, a strong correlation was established between the concentration of manganese (Mn) in needle litter and the degradation of litter lignocellulose across boreal forest ecosystems, suggesting that litter decomposition proceeds more efficiently in the presence of Mn. There is good reason to assume that this is due to the critical role of Mn(III)-ligand complexes acting as potent oxidizers in the fungal decomposition of lignocellulose. Here we investigated how litter decomposing organisms redistribute and repurpose the Mn inherently present in fresh plant litter in order to enhance decomposition. For this purpose, we used two 7-year litter decomposition time series collected at sites at the H.J. Andrews Experimental Forest with widely differing decomposition rates. Spatially-resolved X-ray absorption spectroscopy and wet-chemical extractions were used to track pathways of microbially-mediated Mn transport and associated changes in its speciation in each annual litter layer. The cycling of Mn and other metal cations (e.g., Ca and Fe) was then related to changes in the litter chemistry as documented by 13C TMAH and FTIR. Our results show that, as litter decomposition progresses, reduced Mn in the vascular system of fresh needles is transformed into oxidized forms concentrated in Mn oxide precipitates. This transformation of Mn into more reactive forms proceeds faster at the site of greater decomposition. Our imaging data suggests that during this process Mn

  4. Thermal decomposition of ammonium nitrate in supercritical water

    SciTech Connect

    Luan, Li; Proesmans, P.I.; Buelow, S.J.

    1996-10-01

    Thermal decomposition of neat NH{sub 4}NO{sub 3} has been the subject of many investigations over the past years. The reaction process is surprisingly complicated and depends largely on the reaction environment. For example, trace amounts of NH{sub 3}, HNO{sub 3} and H{sub 2}O are shown to affect the reaction significantly. In this research, NH{sub 4}NO{sub 3} decompostion was investigated in supercritical water. Reactions were evaluated in the presence of additional components such as organic compounds (CH{sub 3}OH, CH{sub 3}COOH, phenol), KN(NO{sub 2}){sub 2}, H{sub 2}O{sub 2}. Experiments were performed at varying temperatures, reaction times, NH{sub 4}NO{sub 3}, H{sub 2}O{sub 2} and organic compound concentrations. Gaseous, liquid and solid products were collected and analysed. The experimental results provided insight of the reaction chemistry which will be discussed in detail.

  5. Above and belowground controls on litter decomposition in semiarid ecosystems: effects of solar radiation, water availability and litter quality

    NASA Astrophysics Data System (ADS)

    Austin, A. T.; Araujo, P. I.; Leva, P. E.; Ballare, C. L.

    2008-12-01

    The integrated controls on soil organic matter formation in arid and semiarid ecosystems are not well understood and appear to stem from a number of interacting controls affecting above- and belowground carbon turnover. While solar radiation has recently been shown to have an important direct effect on carbon loss in semiarid ecosystems as a result of photochemical mineralization of aboveground plant material, the mechanistic basis for photodegradative losses is poorly understood. In addition, there are large potential differences in major controls on above- and belowground decomposition in low rainfall ecosystems. We report on a mesocosm and field study designed to examine the relative importance of different wavelengths of solar radiation, water availability, position of senescent material above- and belowground and the importance of carbon litter quality in determining rates of abiotic and biotic decomposition. In a factorial experiment of mesocosms, we incubated leaf and root litter simultaneously above- and belowground and manipulated water availability with large and small pulses. Significant interactions between position-litter type and position-pulse sizes demonstrated interactive controls on organic mass loss. Aboveground decomposition showed no response to pulse size or litter type, as roots and leaves decomposed equally rapidly under all circumstances. In contrast, belowground decomposition was significantly altered by litter type and water pulses, with roots decomposing significantly slower and small water pulses reducing belowground decomposition. In the field site, using plastic filters which attenuated different wavelengths of natural solar radiation, we found a highly significant effect of radiation exclusion on mass loss and demonstrated that both UV-A and short-wave visible light can have important impacts on photodegradative carbon losses. The combination of position and litter quality effects on litter decomposition appear to be critical for the

  6. Plants Regulate Soil Organic Matter Decomposition in Response to Sea Level Rise

    NASA Astrophysics Data System (ADS)

    Megonigal, P.; Mueller, P.; Jensen, K.

    2014-12-01

    Tidal wetlands have a large capacity for producing and storing organic matter, making their role in the global carbon budget disproportionate to their land area. Most of the organic matter stored in these systems is in soils where it contributes 2-5 times more to surface accretion than an equal mass of minerals. Soil organic matter (SOM) sequestration is the primary process by which tidal wetlands become perched high in the tidal frame, decreasing their vulnerability to accelerated sea level rise. Plant growth responses to sea level rise are well understood and represented in century-scale forecast models of soil surface elevation change. We understand far less about the response of soil organic matter decomposition to rapid sea level rise. Here we quantified the effects of sea level on SOM decomposition rates by exposing planted and unplanted tidal marsh monoliths to experimentally manipulated flood duration. The study was performed in a field-based mesocosm facility at the Smithsonian's Global Change Research Wetland. SOM decomposition rate was quantified as CO2 efflux, with plant- and SOM-derived CO2 separated with a two end-member δ13C-CO2 model. Despite the dogma that decomposition rates are inversely related to flooding, SOM mineralization was not sensitive to flood duration over a 35 cm range in soil surface elevation. However, decomposition rates were strongly and positively related to aboveground biomass (R2≥0.59, p≤0.01). We conclude that soil carbon loss through decomposition is driven by plant responses to sea level in this intensively studied tidal marsh. If this result applies more generally to tidal wetlands, it has important implications for modeling soil organic matter and surface elevation change in response to accelerated sea level rise.

  7. LITTER DECOMPOSITION IN A SIERRA NEVADA RIPARIAN MEADOW AS A FUNCTION OF PLANT SPECIES, DISTANCE FROM STREAM EDGE, AND GRAZING

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A key process in nutrient cycling is decomposition of plant litter and the potential resulting increase in soil nutrient levels. We compare the decomposition rate (k-value yr-1) of four riparian graminoids as influenced by plant species, distance from stream edge (2.5, 20, and 50 m), and grazi...

  8. Changes in bacterial and eukaryotic communities during sewage decomposition in Mississippi River water

    EPA Science Inventory

    Microbial decay processes are one of the mechanisms whereby sewage contamination is reduced in the environment. This decomposition process involves a highly complex array of bacterial and eukaryotic communities from both sewage and ambient waters. However, relatively little is kn...

  9. Plant Diversity Impacts Decomposition and Herbivory via Changes in Aboveground Arthropods

    PubMed Central

    Ebeling, Anne; Meyer, Sebastian T.; Abbas, Maike; Eisenhauer, Nico; Hillebrand, Helmut; Lange, Markus; Scherber, Christoph; Vogel, Anja; Weigelt, Alexandra; Weisser, Wolfgang W.

    2014-01-01

    Loss of plant diversity influences essential ecosystem processes as aboveground productivity, and can have cascading effects on the arthropod communities in adjacent trophic levels. However, few studies have examined how those changes in arthropod communities can have additional impacts on ecosystem processes caused by them (e.g. pollination, bioturbation, predation, decomposition, herbivory). Therefore, including arthropod effects in predictions of the impact of plant diversity loss on such ecosystem processes is an important but little studied piece of information. In a grassland biodiversity experiment, we addressed this gap by assessing aboveground decomposer and herbivore communities and linking their abundance and diversity to rates of decomposition and herbivory. Path analyses showed that increasing plant diversity led to higher abundance and diversity of decomposing arthropods through higher plant biomass. Higher species richness of decomposers, in turn, enhanced decomposition. Similarly, species-rich plant communities hosted a higher abundance and diversity of herbivores through elevated plant biomass and C:N ratio, leading to higher herbivory rates. Integrating trophic interactions into the study of biodiversity effects is required to understand the multiple pathways by which biodiversity affects ecosystem functioning. PMID:25226237

  10. Properties of soil pore space regulate pathways of plant residue decomposition and community structure of associated bacteria

    DOE PAGESBeta

    Negassa, Wakene C.; Guber, Andrey K.; Kravchenko, Alexandra N.; Marsh, Terence L.; Hildebrandt, Britton; Rivers, Mark L.

    2015-07-01

    Physical protection of soil carbon (C) is one of the important components of C storage. However, its exact mechanisms are still not sufficiently lucid. The goal of this study was to explore the influence of soil structure, that is, soil pore spatial arrangements, with and without presence of plant residue on (i) decomposition of added plant residue, (ii) CO₂ emission from soil, and (iii) structure of soil bacterial communities. The study consisted of several soil incubation experiments with samples of contrasting pore characteristics with/without plant residue, accompanied by X-ray micro-tomographic analyses of soil pores and by microbial community analysis ofmore » amplified 16S–18S rRNA genes via pyrosequencing. We observed that in the samples with substantial presence of air-filled well-connected large (>30 µm) pores, 75–80% of the added plant residue was decomposed, cumulative CO₂ emission constituted 1,200 µm C g⁻¹ soil, and movement of C from decomposing plant residue into adjacent soil was insignificant. In the samples with greater abundance of water-filled small pores, 60% of the added plant residue was decomposed, cumulative CO₂ emission constituted 2,000 µm C g⁻¹ soil, and the movement of residue C into adjacent soil was substantial. In the absence of plant residue the influence of pore characteristics on CO₂ emission, that is on decomposition of the native soil organic C, was negligible. The microbial communities on the plant residue in the samples with large pores had more microbial groups known to be cellulose decomposers, that is, Bacteroidetes, Proteobacteria, Actinobacteria, and Firmicutes, while a number of oligotrophic Acidobacteria groups were more abundant on the plant residue from the samples with small pores. This study provides the first experimental evidence that characteristics of soil pores and their air/water flow status determine the phylogenetic composition of the local microbial community and directions and

  11. Water Filtration Using Plant Xylem

    PubMed Central

    Chambers, Valerie; Venkatesh, Varsha; Karnik, Rohit

    2014-01-01

    Effective point-of-use devices for providing safe drinking water are urgently needed to reduce the global burden of waterborne disease. Here we show that plant xylem from the sapwood of coniferous trees – a readily available, inexpensive, biodegradable, and disposable material – can remove bacteria from water by simple pressure-driven filtration. Approximately 3 cm3 of sapwood can filter water at the rate of several liters per day, sufficient to meet the clean drinking water needs of one person. The results demonstrate the potential of plant xylem to address the need for pathogen-free drinking water in developing countries and resource-limited settings. PMID:24587134

  12. Decomposition of plant-sourced carbon compounds by heterotrophic betaproteobacteria isolated from a tropical Costa Rican bromeliad.

    PubMed

    Klann, Jane; McHenry, Alexandra; Montelongo, Carin; Goffredi, Shana K

    2016-06-01

    Betaproteobacteria were the most common isolates from the water-filled tank of a Costa Rican bromeliad. Isolates included eight species from the orders Neisseriales and Burkholderiales, with close relatives recovered previously from tropical soils, wetlands, freshwater, or in association with plants. Compared to close relatives, the isolates displayed high temperature and comparatively low pH optima, reflecting the tropical, acidic nature of the bromeliad tank. Bromeliad-associated bacteria most closely related to Chromobacterium, Herbaspirillum, and Aquitalea were all isolated exclusively at pH 6, while Ralstonia, Cupriavidus, and three species of Burkholderia were isolated mostly at pH 4. Activity profiles for the isolates suggest pervasive capabilities for the breakdown of plant-sourced organics, including d-galacturonic acid, mannitol, d-xylose, and l-phenylalanine, also reflecting a niche dominated by decomposition of leaves from the overlying canopy, which become entrained in the tanks. Metabolic activity profiles were overlapping between the Burkholderiales, isolated at pH 4, and the Neisseriales, isolated at pH 6, suggesting that plant material decomposition, which is presumably the underlying process sustaining the tank community and possibly the plant itself, occurs in the tanks at both pH extremes. These results suggest that bromeliad-associated betaproteobacteria may play an important role in the cycling of carbon in this unusual aquatic habitat. PMID:26918550

  13. Succession change of microorganisms on plant waste decomposition in simulation modelling field experiment

    NASA Astrophysics Data System (ADS)

    Vinogradova, Julia; Perminova, Evgenia; Khabibullina, Fluza; Kovaleva, Vera; Lapteva, Elena

    2016-04-01

    Plant waste decomposition processes are closely associated with living activity of soil microbiota in aboveground ecosystems. Functional activity of microorganisms and soil invertebrates determines plant material transformation rate whereby changes in plant material chemical composition during destruction - succession change of soil biota. The purpose of the work was revealing the mechanism of microorganisms succession change during plant waste decomposition in middle-taiga green-moss spruce forests and coniferous-deciduous secondary stands formed after earlier cut bilberry spruce forests. The study materials were undisturbed bilberry spruce forest (Sample Plot 1 - SP1) and coniferous-deciduous secondary stands which were formed after tree cutting activities of 2001-2002 (SP2) and 1969 and 1970 (SP3). Plant material decomposition intensity was determined in microcosms isolated into kapron bags with cell size of 1 mm. At SP1 and SP2, test material was living mosses and at SP3 - fallen birch and aspen leaves. Every test material was exposed for 2 years. Destruction rate was calculated as a weight loss for a particular time period. Composition of micromycetes which participated in plant material decomposition was assessed by the method of inoculation of soil extract to Getchinson's medium and acidified Czapek's medium (pH=4.5). Microbe number and biomass was analyzed by the method of luminescent microscopy. Chemical analysis of plant material was done in the certified Ecoanalytical Laboratory of the Institute of Biology Komi SC UrD RAS. Finally, plant material destruction intensity was similar for study plots and comprised 40-44 % weight loss for 2 years. The strongest differences in plant material decomposition rate between undisturbed spruce forests and secondary after-cut stands were observed at first stages of destruction process. In the first exposition year, mineralizing processes were most active in undisturbed spruce forest. Decomposition rate in cuts at that

  14. Power Plant Water Intake Assessment.

    ERIC Educational Resources Information Center

    Zeitoun, Ibrahim H.; And Others

    1980-01-01

    In order to adequately assess the impact of power plant cooling water intake on an aquatic ecosystem, total ecosystem effects must be considered, rather than merely numbers of impinged or entrained organisms. (Author/RE)

  15. Plant transpiration distillation of water

    SciTech Connect

    Virostko, M.K.; Spielberg, J.I.

    1986-01-01

    A project using solar energy and the transpiration of plants for the distillation of water is described. Along with determining which of three plants thrived best growing in a still, the experiment also revealed that the still functioned nearly as well in inclement weather as in fair weather.

  16. Waste Water Plant Operators Manual.

    ERIC Educational Resources Information Center

    Washington State Coordinating Council for Occupational Education, Olympia.

    This manual for sewage treatment plant operators was prepared by a committee of operators, educators, and engineers for use as a reference text and handbook and to serve as a training manual for short course and certification programs. Sewage treatment plant operators have a responsibility in water quality control; they are the principal actors in…

  17. Deposition, decomposition and stabilization of peroxides in Santiago City dew waters.

    PubMed

    Rubio, María A; Alvarado, Leonor; Villena, Guillermo; Pizarro, Jaime; Lissi, Eduardo

    2003-09-01

    Peroxides present in Santiago City dew waters readily decompose with first order kinetics. In order to minimize the loss of peroxides during the time elapsed between deposition and collection, the collectors were pre-treated with a mercury chloride solution. This reduces, but not completely eliminates, the decomposition. A correction is introduced by a comparison of the levels and decomposition kinetics of the samples collected in treated and untreated collectors. The average concentration estimated by this procedure was 8.1 microM. The mechanism of peroxide decomposition and its stabilization is discussed. PMID:12922065

  18. Mechanisms of Decomposition of Organic Compounds by Water Plasmas at Atmospheric Pressure

    NASA Astrophysics Data System (ADS)

    Narengerile; Nishioka, Hiroshi; Watanabe, Takayuki

    2011-08-01

    The decomposition of acetone, methanol, and ethanol by water plasmas at atmospheric pressure has been investigated using a direct current (DC) discharge. At torch powers of 910-1050 W and organic compound concentrations of 1-10 mol %, the decomposition rate of methanol was over 99.99%, while those of acetone and/or ethanol was 96-99%. The concentrations of H2 obtained were 65-71% in the effluent gas and the removal efficiencies of 90-95% for total organic carbon (TOC) were achieved in liquid effluent for any compounds by pyrolysis. Over 50 wt % carbon in acetone or ethanol fed as the plasma supporting gas was transformed into soot, while the soot formation was negligible during methanol decomposition. On the basis of the experimental results, the mechanisms of decomposition of organic compounds in water plasmas were proposed and the mechanism of soot formation was clarified for the first time.

  19. Influence of Sodium Carbonate on Decomposition of Formic Acid by Discharge inside Bubble in Water

    NASA Astrophysics Data System (ADS)

    Iwabuchi, Masashi; Takahashi, Katsuyuki; Takaki, Koichi; Satta, Naoya

    2015-09-01

    An influence of sodium carbonate on decomposition of formic acid by discharge inside bubble in water was investigated. Oxygen or argon gases were injected into the water through a vertically positioned glass tube, in which the high-voltage wire electrode was placed to generate plasmas at low applied voltage. The concentration of formic acid was determined by ion chromatography. In the case of addition of sodium carbonate, the pH value increased with decomposition of the formic acid. In the case of oxygen injection, the increase of pH value contributed to improve an efficiency of the formic acid decomposition because the reaction rate of ozone and formic acid increased with increasing pH value. In the case of argon injection, the decomposition rate was not affected by the pH value owing to the high rate constants for loss of hydroxyl radicals.

  20. Dual role of lignin in plant litter decomposition in terrestrial ecosystems

    PubMed Central

    Austin, Amy T.; Ballaré, Carlos L.

    2010-01-01

    Plant litter decomposition is a critical step in the formation of soil organic matter, the mineralization of organic nutrients, and the carbon balance in terrestrial ecosystems. Biotic decomposition in mesic ecosystems is generally negatively correlated with the concentration of lignin, a group of complex aromatic polymers present in plant cell walls that is recalcitrant to enzymatic degradation and serves as a structural barrier impeding microbial access to labile carbon compounds. Although photochemical mineralization of carbon has recently been shown to be important in semiarid ecosystems, litter chemistry controls on photodegradative losses are not understood. We evaluated the importance of litter chemistry on photodegradation of grass litter and cellulose substrates with varying levels of lignin [cellulose-lignin (CL) substrates] under field conditions. Using wavelength-specific light attenuation filters, we found that light-driven mass loss was promoted by both UV and visible radiation. The spectral dependence of photodegradation correlated with the absorption spectrum of lignin but not of cellulose. Field incubations demonstrated that increasing lignin concentration reduced biotic decomposition, as expected, but linearly increased photodegradation. In addition, lignin content in CL substrates consistently decreased in photodegradative incubations. We conclude that lignin has a dual role affecting litter decomposition, depending on the dominant driver (biotic or abiotic) controlling carbon turnover. Under photodegradative conditions, lignin is preferentially degraded because it acts as an effective light-absorbing compound over a wide range of wavelengths. This mechanistic understanding of the role of lignin in plant litter decomposition will allow for more accurate predictions of carbon dynamics in terrestrial ecosystems. PMID:20176940

  1. Temperature and plant species control over litter decomposition in Alaskan tundra

    SciTech Connect

    Hobbie, S.E.

    1996-11-01

    This study compared effects of increased temperature and litter from different Alaskan tundra plant species on cycling of carbon and nitrogen through litter and soil in microcosms. Warming between 4{degrees} and 10{degrees}C significantly increased rates of soil and litter respiration, litter decomposition, litter nitrogen release, and soil net nitrogen mineralization. Thus, future warming will directly increase rates of carbon and nitrogen cycling through litter and soil in tundra. In addition, differences among species` litter in rates of decomposition, N release, and effects on soil net nitrogen mineralization were sometimes larger than differences between the two temperature treatments within a species. Thus, changes in plant community structure and composition associated with future warming will have important consequences for how elements cycle through litter and soil in tundra. In general, species within a growth form (graminoids, evergreen shrubs, deciduous shrubs, and mosses) were more similar in their effects on decomposition than were species belonging to different growth forms, with gramminoid litter having the fastest rate and litter of deciduous shrubs and mosses having the slowest rates. Differences in rates of litter decomposition were more related to carbon quality than to nitrogen concentration. Increased abundance of deciduous shrubs with future climate warming will promote carbon storage, because of their relatively large allocation to woody stems that decompose slowly. Changes in moss abundance will also have important consequences for future carbon and nitrogen cycling, since moss litter is extremely recalcitrant and has a low potential to immobilize nitrogen. 82 refs., 8 figs., 7 tabs.

  2. Differential contribution of soil biota groups to plant litter decomposition as mediated by soil use

    PubMed Central

    Falco, Liliana B.; Sandler, Rosana V.; Coviella, Carlos E.

    2015-01-01

    Plant decomposition is dependant on the activity of the soil biota and its interactions with climate, soil properties, and plant residue inputs. This work assessed the roles of different groups of the soil biota on litter decomposition, and the way they are modulated by soil use. Litterbags of different mesh sizes for the selective exclusion of soil fauna by size (macro, meso, and microfauna) were filled with standardized dried leaves and placed on the same soil under different use intensities: naturalized grasslands, recent agriculture, and intensive agriculture fields. During five months, litterbags of each mesh size were collected once a month per system with five replicates. The remaining mass was measured and decomposition rates calculated. Differences were found for the different biota groups, and they were dependant on soil use. Within systems, the results show that in the naturalized grasslands, the macrofauna had the highest contribution to decomposition. In the recent agricultural system it was the combined activity of the macro- and mesofauna, and in the intensive agricultural use it was the mesofauna activity. These results underscore the relative importance and activity of the different groups of the edaphic biota and the effects of different soil uses on soil biota activity. PMID:25780777

  3. Differential contribution of soil biota groups to plant litter decomposition as mediated by soil use.

    PubMed

    Castro-Huerta, Ricardo A; Falco, Liliana B; Sandler, Rosana V; Coviella, Carlos E

    2015-01-01

    Plant decomposition is dependant on the activity of the soil biota and its interactions with climate, soil properties, and plant residue inputs. This work assessed the roles of different groups of the soil biota on litter decomposition, and the way they are modulated by soil use. Litterbags of different mesh sizes for the selective exclusion of soil fauna by size (macro, meso, and microfauna) were filled with standardized dried leaves and placed on the same soil under different use intensities: naturalized grasslands, recent agriculture, and intensive agriculture fields. During five months, litterbags of each mesh size were collected once a month per system with five replicates. The remaining mass was measured and decomposition rates calculated. Differences were found for the different biota groups, and they were dependant on soil use. Within systems, the results show that in the naturalized grasslands, the macrofauna had the highest contribution to decomposition. In the recent agricultural system it was the combined activity of the macro- and mesofauna, and in the intensive agricultural use it was the mesofauna activity. These results underscore the relative importance and activity of the different groups of the edaphic biota and the effects of different soil uses on soil biota activity. PMID:25780777

  4. Rhizosphere impacts on peat decomposition and nutrient cycling across a natural water table gradient

    NASA Astrophysics Data System (ADS)

    Gill, A. L.; Finzi, A.

    2014-12-01

    High latitude forest and peatland soils represent a major terrestrial carbon store sensitive to climate change. Warming temperatures and increased growing-season evapotranspiration are projected to reduce water table (WT) height in continental peatlands. WT reduction increases peat aerobicity and facilitates vascular plant and root growth. Root-associated microbial communities are exposed to a different physical and chemical environment than microbial communities in non-root associated "bulk" peat, and therefore have distinct composition and function within the soil system. As the size of the peatland rhizosphere impacts resources available to the microbial communities, transitions from a root-free high water table peatland to a root-dominated low WT peatland may alter seasonal patterns of microbial community dynamics, enzyme production, and carbon storage within the system. We used a natural water table gradient in Caribou Bog near Orono, ME to explore the influence of species composition, root biomass, and rhizosphere size on seasonal patterns in microbial community structure, enzyme production, and carbon mineralization. We quantified root biomass across the water table gradient and measured microbial biomass carbon and nitrogen, C mineralization, N mineralization, and exoenzyme activity in root-associated and bulk peat samples throughout the 2013 growing season. Microbial biomass was consistently higher in rhizosphere-associated soils and peaked in the spring. Microbial biomass CN and enzyme activity was higher in rhizosphere-associated soil, likely due to increased mycorrhizal abundance. Exoenzyme activity peaked in the fall, with a larger relative increase in enzyme activity in rhizosphere peat, while carbon mineralization rates did not demonstrate a strong seasonal pattern. The results suggest that rhizosphere-associated peat sustains higher and more variable rates of enzyme activity throughout the growing season, which results in higher rates of carbon

  5. Glucose and fructose decomposition in subcritical and supercritical water: Detailed reaction pathway, mechanisms, and kinetics

    SciTech Connect

    Kabyemela, B.M.; Adschiri, T.; Malaluan, R.M.; Arai, K.

    1999-08-01

    The authors are developing a new catalyst-free process of cellulose decomposition in supercritical water. In their initial study on the cellulose decomposition in supercritical water, the main products of cellulose decomposition were found to be oligomers of glucose (cellobiose, cellotriose, etc.) and glucose at short residence times (400 C, 25 MPa, 0.05 s). The kinetics of glucose at these conditions can be useful in understanding the reaction pathways of cellulose. Experiments were performed on the products of glucose decomposition at short residence times to elucidate the reaction pathways and evaluate kinetics of glucose and fructose decomposition in sub- and supercritical water. The conditions were a temperature of 300--400 C and pressure of 25--40 MPa for extremely short residence times between 0.02 and 2 s. The products of glucose decomposition were fructose, a product of isomerization, 1,6-anhydroglucose, a product of dehydration, and erythrose and glyceraldehyde, products of C-C bond cleavage. Fructose underwent reactions similar to glucose except that it did not form 1,6-anhydroglucose and isomerization to glucose is negligible. The mechanism for the products formed from C-C bond cleavage could be explained by reverse aldol condensation and the double-bond rule of the respective enediols formed during the Lobry de Bruyn Alberda van Ekenstein transformation. The differential equations resulting from the proposed pathways were fit to experimental results to obtain the kinetic rate constants.

  6. Photogeneration of active formate decomposition catalysts to produce hydrogen from formate and water

    DOEpatents

    King, Jr., Allen D.; King, Robert B.; Sailers, III, Earl L.

    1983-02-08

    A process for producing hydrogen from formate and water by photogenerating an active formate decomposition catalyst from transition metal carbonyl precursor catalysts at relatively low temperatures and otherwise mild conditions is disclosed. Additionally, this process may be expanded to include the generation of formate from carbon monoxide and hydroxide such that the result is the water gas shift reaction.

  7. Linking Predation Risk, Herbivore Physiological Stress and Microbial Decomposition of Plant Litter

    PubMed Central

    Schmitz, Oswald J.; Bradford, Mark A.; Strickland, Michael S.; Hawlena, Dror

    2013-01-01

    The quantity and quality of detritus entering the soil determines the rate of decomposition by microbial communities as well as recycle rates of nitrogen (N) and carbon (C) sequestration1,2. Plant litter comprises the majority of detritus3, and so it is assumed that decomposition is only marginally influenced by biomass inputs from animals such as herbivores and carnivores4,5. However, carnivores may influence microbial decomposition of plant litter via a chain of interactions in which predation risk alters the physiology of their herbivore prey that in turn alters soil microbial functioning when the herbivore carcasses are decomposed6. A physiological stress response by herbivores to the risk of predation can change the C:N elemental composition of herbivore biomass7,8,9 because stress from predation risk increases herbivore basal energy demands that in nutrient-limited systems forces herbivores to shift their consumption from N-rich resources to support growth and reproduction to C-rich carbohydrate resources to support heightened metabolism6. Herbivores have limited ability to store excess nutrients, so stressed herbivores excrete N as they increase carbohydrate-C consumption7. Ultimately, prey stressed by predation risk increase their body C:N ratio7,10, making them poorer quality resources for the soil microbial pool likely due to lower availability of labile N for microbial enzyme production6. Thus, decomposition of carcasses of stressed herbivores has a priming effect on the functioning of microbial communities that decreases subsequent ability to of microbes to decompose plant litter6,10,11. We present the methodology to evaluate linkages between predation risk and litter decomposition by soil microbes. We describe how to: induce stress in herbivores from predation risk; measure those stress responses, and measure the consequences on microbial decomposition. We use insights from a model grassland ecosystem comprising the hunting spider predator (Pisuarina

  8. Initial impacts of altered UVB radiation on plant growth and decomposition in shortgrass steppe

    NASA Astrophysics Data System (ADS)

    King, Jennifer Y.; Milchunas, Daniel G.; Mosier, Arvin R.; Moore, John C.; Quirk, Meghan H.; Morgan, Jack A.; Slusser, James R.

    2003-11-01

    We initiated a study in winter 2000 in a Colorado shortgrass steppe to investigate effects of altered ultraviolet-B (UVB) radiation and altered precipitation on plant growth, plant tissue decomposition, and litter faunal activity. In the field, open-air structures were constructed of solid plastic sheet material that either passed all wavelengths of solar radiation or passed only wavelengths greater than 400 nm (UVB =280-315 nm). Preliminary results indicate decreases in warm-season grass production under UVB radiation and drought conditions. Analysis of fiber constituents shows some significant seasonal and UVB treatment effects. The results of in vitro digestible dry matter analyses show significantly higher digestibility with UVB. Simulated grazing increased plant production, but there were no UVB by grazing interactions. Litter decomposition was affected by UVB exposure, the CO2 growing conditions, and precipitation level. Under dry conditions, UVB radiation tended to increase litter decomposition, as measured by mass loss. There were no clear initial effects of UVB treatment on soluble and fiber constituents of litter. Exclusion of UVB resulted in reduced fungal hyphae counts in ambient CO2-grown litter collected in fall 2002. Preliminary results indicate that litter arthropod density was lower with exposure to UVB and also lower under drought conditions.

  9. Labile Compounds in Plant Litter Reduce the Sensitivity of Decomposition to Warming and Altered Precipitation

    NASA Astrophysics Data System (ADS)

    Suseela, V.; Tharayil, N.; Xing, B.; Dukes, J. S.

    2013-12-01

    sensitive to warming and altered precipitation. The significant effects of precipitation on mass loss and chemical composition, even in the late stages of litter decomposition, reveal the potential of climate to alter the amount and quality of carbon in plant litter available for sequestration. These results emphasize that litter chemical composition has an overriding effect on the climate sensitivity of decomposition; thus, litter quality may regulate litter-derived carbon sequestration under future climates.

  10. Solar radiation uncorks the lignin bottleneck on plant litter decomposition in terrestrial ecosystems

    NASA Astrophysics Data System (ADS)

    Austin, A.; Ballare, C. L.; Méndez, M. S.

    2015-12-01

    Plant litter decomposition is an essential process in the first stages of carbon and nutrient turnover in terrestrial ecosystems, and together with soil microbial biomass, provide the principal inputs of carbon for the formation of soil organic matter. Photodegradation, the photochemical mineralization of organic matter, has been recently identified as a mechanism for previously unexplained high rates of litter mass loss in low rainfall ecosystems; however, the generality of this process as a control on carbon cycling in terrestrial ecosystems is not known, and the indirect effects of photodegradation on biotic stimulation of carbon turnover have been debated in recent studies. We demonstrate that in a wide range of plant species, previous exposure to solar radiation, and visible light in particular, enhanced subsequent biotic degradation of leaf litter. Moreover, we demonstrate that the mechanism for this enhancement involves increased accessibility for microbial enzymes to plant litter carbohydrates due to a reduction in lignin content. Photodegradation of plant litter reduces the structural and chemical bottleneck imposed by lignin in secondary cell walls. In litter from woody plant species, specific interactions with ultraviolet radiation obscured facilitative effects of solar radiation on biotic decomposition. The generalized positive effect of solar radiation exposure on subsequent microbial activity is mediated by increased accessibility to cell wall polysaccharides, which suggests that photodegradation is quantitatively important in determining rates of mass loss, nutrient release and the carbon balance in a broad range of terrestrial ecosystems.

  11. Water quality time series for Big Melen stream (Turkey): its decomposition analysis and comparison to upstream.

    PubMed

    Karakaya, N; Evrendilek, F

    2010-06-01

    Big Melen stream is one of the major water resources providing 0.268 [corrected] km(3) year(-1) of drinking and municipal water for Istanbul. Monthly time series data between 1991 and 2004 for 25 chemical, biological, and physical water properties of Big Melen stream were separated into linear trend, seasonality, and error components using additive decomposition models. Water quality index (WQI) derived from 17 water quality variables were used to compare Aksu upstream and Big Melen downstream water quality. Twenty-six additive decomposition models of water quality time series data including WQI had R (2) values ranging from 88% for log(water temperature) (P < or = 0.001) to 3% for log(total dissolved solids) (P < or = 0.026). Linear trend models revealed that total hardness, calcium concentration, and log(nitrite concentration) had the highest rate of increase over time. Tukey's multiple comparison pointed to significant decreases in 17 water quality variables including WQI of Big Melen downstream relative to those of Aksu upstream (P < or = 0.001). Monitoring changes in water quality on the basis of watersheds through WQI and decomposition analysis of time series data paves the way for an adaptive management process of water resources that can be tailored in response to effectiveness and dynamics of management practices. PMID:19444637

  12. Carbon isotopic fractionation during decomposition of plant materials of different quality

    NASA Astrophysics Data System (ADS)

    Fernandez, I.; Mahieu, N.; Cadisch, G.

    2003-09-01

    Changes in isotopic 13C composition of solid residues and CO2 evolved during decomposition of C3 and C4 plant materials were monitored over 10 months to determine carbon isotopic fractionation at successive stages of biodegradation. We selected plant materials of different chemical quality, e.g., Zea mays (leaves, stems, coarse roots, and fine roots), Lolium perenne (leaves and roots), Pinus pinaster (needles), and Cocos nucifera (coconut shell) and also characterized these by solid-state 13C NMR. Roots were more lignified than aerial parts of the same species. Lignin was always depleted in 13C (up to 5.2‰) as compared with cellulose from the same sample. Proteins were enriched in 13C in C3 plants but depleted in maize. Cumulative CO2 evolved fitted a double-exponential model with two C pools of different lability. During early stages of decomposition, the CO2-C released was usually 13C depleted as compared with the initial substrate but enriched at posterior stages. Consequently, with ongoing decomposition, the solid residue became 13C depleted, which could only partly be explained by an accumulation of lignin-C. The extension of the initial 13C depleted CO2-C phase was significantly correlated with the labile substrate C content, acid-detergent soluble fraction, and total N, pointing to a direct influence of plant quality on C isotopic dynamics during early stages of biodegradation. This isotopic fractionation can also lead to an underestimation of the contribution of plant residues to CO2-C when incubated in soils. We discuss possible implications of these mechanisms of 13C fractionation in ecosystems.

  13. Ethanol and phenanthrene increase the biomass of fungal assemblages and decrease plant litter decomposition in streams.

    PubMed

    Barros, Diana; Oliveira, Patrícia; Pascoal, Cláudia; Cássio, Fernanda

    2016-09-15

    Fungi, particularly aquatic hyphomycetes, have been recognized as playing a dominant role in microbial decomposition of plant litter in streams. In this study, we used a microcosm experiment with different levels of fungal diversity (species number and identity) using monocultures and combinations with up to five aquatic hyphomycete species (Articulospora tetracladia, Tricladium splendens, Heliscus submersus, Tetrachaetum elegans and Flagellospora curta) to assess the effects of ethanol and phenanthrene on three functional measures: plant litter decomposition, fungal biomass accrual and reproduction. Alder leaves were conditioned by fungi for 7days and then were exposed to phenanthrene (1mgL(-1)) dissolved in ethanol (0.1% final concentration) or ethanol (at the concentration used to solubilise phenanthrene) for further 24days. Exposure to ethanol alone or in combination with phenanthrene decreased leaf decomposition and fungal reproduction, but increased fungal biomass produced. All aspects of fungal activity varied with species number. Fungal activity in polycultures was generally higher than that expected from the sum of the weighted performances of participating species in monoculture, suggesting complementarity between species. However, the activity of fungi in polycultures did not exceed the activity of the most productive species either in the absence or presence of ethanol alone or with phenanthrene. PMID:27186876

  14. Kinetics of glucose epimerization and decomposition in subcritical and supercritical water

    SciTech Connect

    Kabyemela, B.M.; Adschiri, Tadafumi; Malaluan, R.M.; Arai, Kunio

    1997-05-01

    Glucose decomposition kinetics in subcritical and supercritical water were studied for the temperatures 573, 623, and 673 K, pressures between 25 and 40 MPa, and residence times between 0.02 and 2 s. Glucose decomposition products were fructose, saccharinic acids, erythrose, glyceraldehyde, 1,6-anhydroglucose, dihydroxyacetone, pyruvaldehyde, and small amounts of 5-hydroxymethylfurfural. Fructose was also studied and found to decompose to products similar to those of glucose, except that its epimerization to glucose was negligibly low and no formation of 1,6-anhydroglucose was detected. The authors concluded that only the forward epimerization of glucose to fructose was important. The glucose decomposition pathway could be described in terms of a forward epimerization rate, r{sub gf}, a fructose to decomposition products rate, r{sub f}, and a glucose to decomposition products rate, r{sub g}. A kinetic model based on this pathway gave good correlation of the experimental data. In the subcritical region, r{sub g}, r{sub f}, and r{sub gf} showed only small changes with pressure at a given temperature. In the supercritical region, the rate of glucose decomposition decreased with pressure at a given temperature. The reason for this decrease was mainly due to the decrease in r{sub gf}. The pressure effect in the supercritical region shows that there is a shift among the kinetic rates, which can lead to higher selectivity for glucose when decomposing cellulosic materials.

  15. Decomposition and plant-available nitrogen in biosolids: laboratory studies, field studies, and computer simulation.

    PubMed

    Gilmour, John T; Cogger, Craig G; Jacobs, Lee W; Evanylo, Gregory K; Sullivan, Dan M

    2003-01-01

    This research combines laboratory and field studies with computer simulation to characterize the amount of plant-available nitrogen (PAN) released when municipal biosolids are land-applied to agronomic crops. In the laboratory studies, biosolids were incubated in or on soil from the land application sites. Mean biosolids total C, organic N, and C to N ratio were 292 g kg(-1), 41.7 g kg(-1), and 7.5, respectively. Based on CO2 evolution at 25 degrees C and optimum soil moisture, 27 of the 37 biosolids-soil combinations had two decomposition phases. The mean rapid and slow fraction rate constants were 0.021 and 0.0015 d(-1), respectively, and the rapid fraction contained 23% of the total C assuming sequential decomposition. Where only one decomposition phase existed, the mean first order rate constant was 0.0046 d(-1). The mean rate constant for biosolids stored in lagoons for an extended time was 0.00097 d(-1). The only treatment process that was related to biosolids treatment was stabilization by storage in a lagoon. Biosolids addition rates (dry basis) ranged from 1.3 to 33.8 Mg ha(-1) with a mean value of 10.6 Mg ha(-1). A relationship between fertilizer N rate and crop response was used to estimate observed PAN at each site. Mean observed PAN during the growing season was 18.9 kg N Mg(-1) or 37% of the biosolids total N. Observed PAN was linearly related to biosolids total N. Predicted PAN using the computer model Decomposition, actual growing-season weather, actual analytical data, and laboratory decomposition kinetics compared well with observed PAN. The mean computer model prediction of growing-season PAN was 19.2 kg N Mg(-1) and the slope of the regression between predicted and observed PAN was not significantly different from unity. Predicted PAN obtained using mean decomposition kinetics was related to predicted PAN using actual decomposition kinetics suggesting that mean rate constants, actual weather, and actual analytical data could be used in

  16. Effect of silver and copper ions on the decomposition of ozone in water

    NASA Astrophysics Data System (ADS)

    Ershov, B. G.; Morozov, P. A.; Gordeeev, A. V.

    2012-12-01

    Features of the kinetics of ozone decomposition in water at pH 2 are studied depending on the concentration of silver and copper ions that are present. The existence of a critical concentration of metal ions (˜3-6 × 10-6 M) is established, below which ions slow the rate of ozone decomposition and above which the accelerate the process. It is concluded that the first region is due to the capture of hydroxyl and other radicals by metal ions, inhibiting the chain of ozone decomposition in water. A further increase in the concentration of ions leads to dominance of their direct interaction with molecules of ozone. A mechanism for the process is proposed and the rate constants of reaction of ozone with silver ions and copper are calculated (0.033 and 0.06 M-1 s-1, respectively).

  17. Reconciling Phylogeny and Function During Plant Litter Decomposition by High-Throughput Functional Metagenomics

    NASA Astrophysics Data System (ADS)

    Nyyssonen, M.; Weihe, C.; Goulden, M.; Treseder, K. K.; Martiny, J.; Martiny, A.; Allison, S. D.; Brodie, E. L.

    2012-12-01

    Integrating information on microbial diversity and functionality with ecosystem processes may be critical to predicting how ecosystems respond to environmental change. While theoretical models can be used to link microbial processes to environmental responses and rates, accurate predictions of ecosystem functioning would benefit from detailed information on microbial community composition and function. In this study, our aim was to identify functional traits involved in plant litter decomposition, a model process for carbon cycling, from decomposing plant litter. The overall goal is then to link these traits with individual microbial taxa and use this information to build predictive trait-based models of ecosystem responses to global change. In order to identify activities involved in plant litter decomposition we used automated high-throughput assays for functional screening of metagenomic fosmid libraries prepared from decomposing plant litter. Litter was collected over 15 month period from a global change field experiment undergoing rainfall and nitrogen manipulations. We identified over 600 cellulose, hemicellulose, chitin and starch hydrolyzing clones following screening of over 300,000 clones. The frequency of positive clones was ten times lower during dry season but no significant differences in hit rates were observed between different treatments. The positive clones were shotgun sequenced on the Illumina sequencing platform and the identified hydrolytic genes were shown to represent variety bacterial taxonomic groups including Proteobacteria and Bacteroidetes.

  18. Thermochemical processes for hydrogen production by water decomposition. Final report

    SciTech Connect

    Perlmutter, D.D.

    1980-08-01

    The principal contributions of the research are in the area of gas-solid reactions, ranging from models and data interpretation for fundamental kinetics and mixing of solids to simulations of engineering scale reactors. Models were derived for simulating the heat and mass transfer processes inside the reactor and tested by experiments. The effects of surface renewal of solids on the mass transfer phenomena were studied and related to the solid mixing. Catalysis by selected additives were studied experimentally. The separate results were combined in a simulation study of industrial-scale rotary reactor performance. A study was made of the controlled decompositions of a series of inorganic sulfates and their common hydrates, carried out in a Thermogravimetric Analyzer (TGA), a Differential Scanning Calorimeter (DSC), and a Differential Thermal Analyzer (DTA). Various sample sizes, heating rates, and ambient atmospheres were used to demonstrate their influence on the results. The purposes of this study were to: (i) reveal intermediate compounds, (ii) determine the stable temperature range of each compound, and (iii) measure reaction kinetics. In addition, several solid additives: carbon, metal oxides, and sodium chloride, were demonstrated to have catalytic effects to varying degrees for the different salts.

  19. Oxidative decomposition of vitamin C in drinking water.

    PubMed

    Jansson, Patric J; Jung, Hye R; Lindqvist, Christer; Nordström, Tommy

    2004-08-01

    We have previously shown that vitamin C (ascorbic acid) can initiate hydroxyl radical formation in copper contaminated household drinking water. In the present study, we have examined the stability of vitamin C in copper and bicarbonate containing household drinking water. In drinking water samples, contaminated with copper from the pipes and buffered with bicarbonate, 35% of the added vitamin C was oxidized to dehydroascorbic acid within 15 min. After 3h incubation at room temperature, 93% of the added (2 mM) ascorbic acid had been oxidized. The dehydroascorbic acid formed was further decomposed to oxalic acid and threonic acid by the hydrogen peroxide generated from the copper (I) autooxidation in the presence of oxygen. A very modest oxidation of vitamin C occurred in Milli-Q water and in household water samples not contaminated by copper ions. Moreover, addition of vitamin C to commercially sold domestic bottled water samples did not result in vitamin C oxidation. Our results demonstrate that ascorbic acid is rapidly oxidized to dehydroascorbic acid and further decomposed to oxalic- and threonic acid in copper contaminated household tap water that is buffered with bicarbonate. The impact of consuming ascorbic acid together with copper and bicarbonate containing drinking water on human health is discussed. PMID:15493459

  20. Thermochemical water decomposition. [hydrogen separation for energy applications

    NASA Technical Reports Server (NTRS)

    Funk, J. E.

    1977-01-01

    At present, nearly all of the hydrogen consumed in the world is produced by reacting hydrocarbons with water. As the supply of hydrocarbons diminishes, the problem of producing hydrogen from water alone will become increasingly important. Furthermore, producing hydrogen from water is a means of energy conversion by which thermal energy from a primary source, such as solar or nuclear fusion of fission, can be changed into an easily transportable and ecologically acceptable fuel. The attraction of thermochemical processes is that they offer the potential for converting thermal energy to hydrogen more efficiently than by water electrolysis. A thermochemical hydrogen-production process is one which requires only water as material input and mainly thermal energy, or heat, as an energy input. Attention is given to a definition of process thermal efficiency, the thermodynamics of the overall process, the single-stage process, the two-stage process, multistage processes, the work of separation and a process evaluation.

  1. Effects of electron acceptors on soluble reactive phosphorus in the overlying water during algal decomposition.

    PubMed

    Wang, Jinzhi; Jiang, Xia; Zheng, Binghui; Niu, Yuan; Wang, Kun; Wang, Wenwen; Kardol, Paul

    2015-12-01

    Endogenous phosphorus (P) release from sediments is an important factor to cause eutrophication and, hence, algal bloom in lakes in China. Algal decomposition depletes dissolved oxygen (DO) and causes anaerobic conditions and therefore increases P release from sediments. As sediment P release is dependent on the iron (Fe) cycle, electron acceptors (e.g., NO3 (-), SO4 (2-), and Mn(4+)) can be utilized to suppress the reduction of Fe(3+) under anaerobic conditions and, as such, have the potential to impair the release of sediment P. Here, we used a laboratory experiment to test the effects of FeCl3, MnO2, and KNO3 on soluble reactive phosphorus (SRP) concentration and related chemical variables in the overlying water column during algal decomposition at different algal densities. Results showed that algal decomposition significantly depleted DO and thereby increased sediment Fe-bound P release. Compared with the control, addition of FeCl3 significantly decreased water SRP concentration through inhibiting sediment P release. Compared with FeCl3, addition of MnO2 has less potential to suppress sediment P release during algal decomposition. Algal decomposition has the potential for NO3 (-) removal from aquatic ecosystem through denitrification and by that alleviates the suppressing role of NO3 (-) on sediment P release. Our results indicated that FeCl3 and MnO2 could be efficient in reducing sediment P release during algal decomposition, with the strongest effect found for FeCl3; large amounts of NO3 (-) were removed from the aquatic ecosystem through denitrification during algal decomposition. Moreover, the amounts of NO3 (-) removal increased with increasing algal density. PMID:26263882

  2. Effects of root decomposition on plant-soil feedback of early- and mid-successional plant species.

    PubMed

    Zhang, Naili; Van der Putten, Wim H; Veen, G F Ciska

    2016-10-01

    Plant-soil feedback (PSF) is an important driver of plant community dynamics. Many studies have emphasized the role of pathogens and symbiotic mutualists in PSFs; however, less is known about the contribution of decomposing litter, especially that of roots. We conducted a PSF experiment, where soils were conditioned by living early- and mid-successional grasses and forbs with and without decomposing roots of conspecific species (conditioning phase). These soils were used to test growth responses of conspecific and heterospecific plant species (feedback phase). The addition of the roots of conspecifics decreased the biomass of both early- and mid-successional plant species in the conditioning phase. In the feedback phase, root addition had positive effects on the biomass of early-successional species and neutral effects on mid-successional species, except when mid-successional grasses were grown in soils conditioned by conspecifics, where effects were negative. Biomass of early- and mid-successional forbs was generally reduced in soils conditioned by conspecifics. We conclude that root decomposition may increase short-term negative PSF effects, but that the effects can become neutral to positive over time, thereby counteracting negative components of PSF. This implies that root decomposition is a key element of PSF and needs to be included in future studies. PMID:27214646

  3. Plant Species Rather Than Climate Greatly Alters the Temporal Pattern of Litter Chemical Composition During Long-Term Decomposition

    PubMed Central

    Li, Yongfu; Chen, Na; Harmon, Mark E.; Li, Yuan; Cao, Xiaoyan; Chappell, Mark A.; Mao, Jingdong

    2015-01-01

    A feedback between decomposition and litter chemical composition occurs with decomposition altering composition that in turn influences the decomposition rate. Elucidating the temporal pattern of chemical composition is vital to understand this feedback, but the effects of plant species and climate on chemical changes remain poorly understood, especially over multiple years. In a 10-year decomposition experiment with litter of four species (Acer saccharum, Drypetes glauca, Pinus resinosa, and Thuja plicata) from four sites that range from the arctic to tropics, we determined the abundance of 11 litter chemical constituents that were grouped into waxes, carbohydrates, lignin/tannins, and proteins/peptides using advanced 13C solid-state NMR techniques. Decomposition generally led to an enrichment of waxes and a depletion of carbohydrates, whereas the changes of other chemical constituents were inconsistent. Inconsistent convergence in chemical compositions during decomposition was observed among different litter species across a range of site conditions, whereas one litter species converged under different climate conditions. Our data clearly demonstrate that plant species rather than climate greatly alters the temporal pattern of litter chemical composition, suggesting the decomposition-chemistry feedback varies among different plant species. PMID:26515033

  4. Plant Species Rather Than Climate Greatly Alters the Temporal Pattern of Litter Chemical Composition During Long-Term Decomposition

    NASA Astrophysics Data System (ADS)

    Li, Yongfu; Chen, Na; Harmon, Mark E.; Li, Yuan; Cao, Xiaoyan; Chappell, Mark A.; Mao, Jingdong

    2015-10-01

    A feedback between decomposition and litter chemical composition occurs with decomposition altering composition that in turn influences the decomposition rate. Elucidating the temporal pattern of chemical composition is vital to understand this feedback, but the effects of plant species and climate on chemical changes remain poorly understood, especially over multiple years. In a 10-year decomposition experiment with litter of four species (Acer saccharum, Drypetes glauca, Pinus resinosa, and Thuja plicata) from four sites that range from the arctic to tropics, we determined the abundance of 11 litter chemical constituents that were grouped into waxes, carbohydrates, lignin/tannins, and proteins/peptides using advanced 13C solid-state NMR techniques. Decomposition generally led to an enrichment of waxes and a depletion of carbohydrates, whereas the changes of other chemical constituents were inconsistent. Inconsistent convergence in chemical compositions during decomposition was observed among different litter species across a range of site conditions, whereas one litter species converged under different climate conditions. Our data clearly demonstrate that plant species rather than climate greatly alters the temporal pattern of litter chemical composition, suggesting the decomposition-chemistry feedback varies among different plant species.

  5. Complementary symbiont contributions to plant decomposition in a fungus-farming termite

    PubMed Central

    Hu, Haofu; Li, Cai; Chen, Zhensheng; Otani, Saria; Nygaard, Sanne; Nobre, Tania; Klaubauf, Sylvia; Schindler, Philipp M.; Hauser, Frank; Pan, Hailin; Yang, Zhikai; Sonnenberg, Anton S. M.; de Beer, Z. Wilhelm; Zhang, Yong; Wingfield, Michael J.; Grimmelikhuijzen, Cornelis J. P.; de Vries, Ronald P.; Korb, Judith; Aanen, Duur K.; Wang, Jun; Boomsma, Jacobus J.; Zhang, Guojie

    2014-01-01

    Termites normally rely on gut symbionts to decompose organic matter but the Macrotermitinae domesticated Termitomyces fungi to produce their own food. This transition was accompanied by a shift in the composition of the gut microbiota, but the complementary roles of these bacteria in the symbiosis have remained enigmatic. We obtained high-quality annotated draft genomes of the termite Macrotermes natalensis, its Termitomyces symbiont, and gut metagenomes from workers, soldiers, and a queen. We show that members from 111 of the 128 known glycoside hydrolase families are represented in the symbiosis, that Termitomyces has the genomic capacity to handle complex carbohydrates, and that worker gut microbes primarily contribute enzymes for final digestion of oligosaccharides. This apparent division of labor is consistent with the Macrotermes gut microbes being most important during the second passage of comb material through the termite gut, after a first gut passage where the crude plant substrate is inoculated with Termitomyces asexual spores so that initial fungal growth and polysaccharide decomposition can proceed with high efficiency. Complex conversion of biomass in termite mounds thus appears to be mainly accomplished by complementary cooperation between a domesticated fungal monoculture and a specialized bacterial community. In sharp contrast, the gut microbiota of the queen had highly reduced plant decomposition potential, suggesting that mature reproductives digest fungal material provided by workers rather than plant substrate. PMID:25246537

  6. Complementary symbiont contributions to plant decomposition in a fungus-farming termite.

    PubMed

    Poulsen, Michael; Hu, Haofu; Li, Cai; Chen, Zhensheng; Xu, Luohao; Otani, Saria; Nygaard, Sanne; Nobre, Tania; Klaubauf, Sylvia; Schindler, Philipp M; Hauser, Frank; Pan, Hailin; Yang, Zhikai; Sonnenberg, Anton S M; de Beer, Z Wilhelm; Zhang, Yong; Wingfield, Michael J; Grimmelikhuijzen, Cornelis J P; de Vries, Ronald P; Korb, Judith; Aanen, Duur K; Wang, Jun; Boomsma, Jacobus J; Zhang, Guojie

    2014-10-01

    Termites normally rely on gut symbionts to decompose organic matter but the Macrotermitinae domesticated Termitomyces fungi to produce their own food. This transition was accompanied by a shift in the composition of the gut microbiota, but the complementary roles of these bacteria in the symbiosis have remained enigmatic. We obtained high-quality annotated draft genomes of the termite Macrotermes natalensis, its Termitomyces symbiont, and gut metagenomes from workers, soldiers, and a queen. We show that members from 111 of the 128 known glycoside hydrolase families are represented in the symbiosis, that Termitomyces has the genomic capacity to handle complex carbohydrates, and that worker gut microbes primarily contribute enzymes for final digestion of oligosaccharides. This apparent division of labor is consistent with the Macrotermes gut microbes being most important during the second passage of comb material through the termite gut, after a first gut passage where the crude plant substrate is inoculated with Termitomyces asexual spores so that initial fungal growth and polysaccharide decomposition can proceed with high efficiency. Complex conversion of biomass in termite mounds thus appears to be mainly accomplished by complementary cooperation between a domesticated fungal monoculture and a specialized bacterial community. In sharp contrast, the gut microbiota of the queen had highly reduced plant decomposition potential, suggesting that mature reproductives digest fungal material provided by workers rather than plant substrate. PMID:25246537

  7. PLANT WATER STATUS INFLUENCES OZONE SENSITIVITY OF BEAN PLANTS

    EPA Science Inventory

    Studies were conducted in a controlled environment chamber to determine the association between plant water status and ozone sensitivity. Bean plants were subjected to various water stress regimes for 4 to 10 days using a semipermeable membrane system which controlled plant water...

  8. Carbon availability triggers the decomposition of plant litter and assimilation of nitrogen by an ectomycorrhizal fungus

    PubMed Central

    Rineau, F; Shah, F; Smits, M M; Persson, P; Johansson, T; Carleer, R; Troein, C; Tunlid, A

    2013-01-01

    The majority of nitrogen in forest soils is found in organic matter–protein complexes. Ectomycorrhizal fungi (EMF) are thought to have a key role in decomposing and mobilizing nitrogen from such complexes. However, little is known about the mechanisms governing these processes, how they are regulated by the carbon in the host plant and the availability of more easily available forms of nitrogen sources. Here we used spectroscopic analyses and transcriptome profiling to examine how the presence or absence of glucose and/or ammonium regulates decomposition of litter material and nitrogen mobilization by the ectomycorrhizal fungus Paxillus involutus. We found that the assimilation of nitrogen and the decomposition of the litter material are triggered by the addition of glucose. Glucose addition also resulted in upregulation of the expression of genes encoding enzymes involved in oxidative degradation of polysaccharides and polyphenols, peptidases, nitrogen transporters and enzymes in pathways of the nitrogen and carbon metabolism. In contrast, the addition of ammonium to organic matter had relatively minor effects on the expression of transcripts and the decomposition of litter material, occurring only when glucose was present. On the basis of spectroscopic analyses, three major types of chemical modifications of the litter material were observed, each correlated with the expression of specific sets of genes encoding extracellular enzymes. Our data suggest that the expression of the decomposition and nitrogen assimilation processes of EMF can be tightly regulated by the host carbon supply and that the availability of inorganic nitrogen as such has limited effects on saprotrophic activities. PMID:23788332

  9. Radiolytic decomposition of multi-class surfactants and their biotransformation products in sewage treatment plant effluents.

    PubMed

    Petrovic, M; Gehringer, P; Eschweiler, H; Barceló, D

    2007-01-01

    Electron beam irradiation (EBI), as one of the most efficient advanced oxidation processes, was applied to the treatment of sewage treatment plant (STP) effluent, with the objective of evaluating the effectiveness of radiolytic decomposition of multi-class surfactants. Target compounds, included several high-volume surfactant groups, such as alkylphenol ethoxylates (APEOs) and their biotransformation products, linear alkylbenzene sulfonates (LAS), alkyl sulfates (AS), alkylether sulfates (AES), coconut diethanol amides (CDEA), alcohol ethoxylates (AEO) and polyethylene glycols (PEGs). EBI treatment of STP effluent (total concentration of APEO-derived compounds 265mugl(-1), being APE(2)C the most abundant by-degradation products) resulted in efficient decomposition of all alkylphenolic compounds; elimination of 94% longer ethoxy chain nonylphenol ethoxylates (NPEO, n(EO)=3-15) was obtained when 3kGy were applied. Slightly less efficient decomposition of short ethoxy chain oligomers (NPEO(1) and NPEO(2)) was observed, resulting in disappearance of about 80% of the initially present compounds. LC-MS analysis of treated wastewater suggested that the mechanism of EBI degradation of APEOs is a combination of two parallel pathways: a progressive shortening and oxidation of the ethoxy chain, which resulted in a formation of short ethoxy chain oligomers and APECs and central fission that resulted in formation of PEGs. Decomposition of APECs at 1kGy initially yielded APs, which were subsequently eliminated applying higher radiation doses. With a radiation dose of 2kGy about 95% of NPE(1)C and 97% of NPE(2)C were decomposed. Similar elimination rates were obtained for octylphenolic compounds. Radiolytic treatment applied was also very effective in removing PEGs formed as by-products from APEO degradation, as well as in decomposing other surfactants, such as linear LAS, AS and AES. PMID:16808959

  10. Daily water level forecasting using wavelet decomposition and artificial intelligence techniques

    NASA Astrophysics Data System (ADS)

    Seo, Youngmin; Kim, Sungwon; Kisi, Ozgur; Singh, Vijay P.

    2015-01-01

    Reliable water level forecasting for reservoir inflow is essential for reservoir operation. The objective of this paper is to develop and apply two hybrid models for daily water level forecasting and investigate their accuracy. These two hybrid models are wavelet-based artificial neural network (WANN) and wavelet-based adaptive neuro-fuzzy inference system (WANFIS). Wavelet decomposition is employed to decompose an input time series into approximation and detail components. The decomposed time series are used as inputs to artificial neural networks (ANN) and adaptive neuro-fuzzy inference system (ANFIS) for WANN and WANFIS models, respectively. Based on statistical performance indexes, the WANN and WANFIS models are found to produce better efficiency than the ANN and ANFIS models. WANFIS7-sym10 yields the best performance among all other models. It is found that wavelet decomposition improves the accuracy of ANN and ANFIS. This study evaluates the accuracy of the WANN and WANFIS models for different mother wavelets, including Daubechies, Symmlet and Coiflet wavelets. It is found that the model performance is dependent on input sets and mother wavelets, and the wavelet decomposition using mother wavelet, db10, can further improve the efficiency of ANN and ANFIS models. Results obtained from this study indicate that the conjunction of wavelet decomposition and artificial intelligence models can be a useful tool for accurate forecasting daily water level and can yield better efficiency than the conventional forecasting models.

  11. (Plant growth with limited water)

    SciTech Connect

    Not Available

    1991-01-01

    The work supported by DOE in the last year built on our earlier findings that stem growth in soybean subjected to limited water is inhibited first by a physical limitation followed in a few hours by metabolic changes that reduce the extensibility of the cell walls. With time, there is modest recovery in extensibility and a 28kD protein accumulates in the walls of the growth-affected cells. A 31kD protein that was 80% similar in amino acid sequence also was present but did not accumulate in the walls of the stem cells. Explorations of the mRNA for these proteins showed that the mRNA for the 28kD protein increased in the shoot in response to water deprivation but the mRNA for the 31kD protein did not accumulate. In contrast, the roots continued to grow and the mRNA for the 31kD protein accumulated but the mRNA for the 28kD protein was undetectable. We also explored how growth occurs in the absence of an external water supply. We found that, under these conditions, internal water is mobilized from surrounding nongrowing or slowly growing tissues and is used by rapidly growing cells. We showed that a low water potential is normally present in the enlarging tissues and is the likely force that extracts water from the surrounding tissues. We found that it involved a gradient in water potential that extended from the xylem to the outlying cells in the enlarging region and was not observed in the slowly growing basal tissue of the stems of the same plant. The gradient was measured directly with single cell determinations of turgor and osmotic potential in intact plants. The gradient may explain instances of growth inhibition with limited water when there is no change in the turgor of the enlarging cells. 17 refs.

  12. Theoretical study of the decomposition of formamide in the presence of water molecules.

    PubMed

    Nguyen, Vinh Son; Orlando, Thomas M; Leszczynski, Jerzy; Nguyen, Minh Tho

    2013-03-28

    Formamide (NH2CHO, FM) has been considered an active key precursor in prebiotic chemistry on early Earth. Under certain conditions such as dry lagoons, FM can decompose to produce reactants that lead to formation of more complex biomolecules. Specifically, FM decomposition follows many reactive channels producing small molecules such as H2, CO, H2O, HCN, HNC, NH3, and HNCO with comparable energy barriers in the range of 73-82 kcal/mol. Due to the likely presence of water on prebiotic Earth and the intrinsic presence of water following FM decomposition, we explore the effects of water oligomers, (H2O)n with n = 1-3, on its dehydration, dehydrogenation, and decarbonylation reactions using quantum chemical computations. Geometries are optimized using MP2/aug-cc-pVxZ calculations (x = D,T), and relative energies are evaluated using coupled-cluster theory CCSD(T) with the aug-cc-pVxZ basis sets (x = D, T, Q). Where possible the coupled-cluster energies are extrapolated to the complete basis set limit (CBS). Water classically acts as an efficient bifunctional catalyst for decomposition. With the presence of one water molecule, the dehydration pathway leading to HCN is favored. When two and three water molecules are involved, dehydration remains energetically favored over other channels and attains an energy barrier of ~30 kcal/mol. PMID:23461351

  13. The Presence of Plants Alters the Effect of Soil Moisture on Soil C Decomposition in Two Different Soil Types

    NASA Astrophysics Data System (ADS)

    Dijkstra, F. A.; Cheng, W.

    2005-12-01

    While it is well known that soil moisture directly affects microbial activity and soil C decomposition, it is unclear if the presence of plants alters these effects through rhizosphere processes. We studied soil moisture effects on soil C decomposition with and without sunflower and soybean. Plants were grown in two different soil types with soil moisture contents of 45 and 85% of field capacity in a greenhouse experiment. We continuously labeled plants with depleted 13C, which allowed us to separate plant-derived CO2-C from original soil-derived CO2-C in soil respiration measurements. We observed an overall increase in soil-derived CO2-C efflux in the presence of plants (priming effect) in both soils with on average a greater priming effect in the high soil moisture treatment (60% increase in soil-derived CO2-C compared to control) than in the low soil moisture treatment (37% increase). Greater plant biomass in the high soil moisture treatment contributed to greater priming effects, but priming effects remained significantly higher after correcting for plant biomass. Possibly, root exudation of labile C may have increased more than plant biomass and may have become more effective in stimulating microbial decomposition in the higher soil moisture treatment. Our results indicate that changing soil moisture conditions can significantly alter rhizosphere effects on soil C decomposition.

  14. Method of generating hydrogen by catalytic decomposition of water

    DOEpatents

    Balachandran, Uthamalingam; Dorris, Stephen E.; Bose, Arun C.; Stiegel, Gary J.; Lee, Tae-Hyun

    2002-01-01

    A method for producing hydrogen includes providing a feed stream comprising water; contacting at least one proton conducting membrane adapted to interact with the feed stream; splitting the water into hydrogen and oxygen at a predetermined temperature; and separating the hydrogen from the oxygen. Preferably the proton conducting membrane comprises a proton conductor and a second phase material. Preferable proton conductors suitable for use in a proton conducting membrane include a lanthanide element, a Group VIA element and a Group IA or Group IIA element such as barium, strontium, or combinations of these elements. More preferred proton conductors include yttrium. Preferable second phase materials include platinum, palladium, nickel, cobalt, chromium, manganese, vanadium, silver, gold, copper, rhodium, ruthenium, niobium, zirconium, tantalum, and combinations of these. More preferably second phase materials suitable for use in a proton conducting membrane include nickel, palladium, and combinations of these. The method for generating hydrogen is preferably preformed in the range between about 600.degree. C. and 1,700.degree. C.

  15. Bacterial and fungal colonization and decomposition of submerged plant litter: consequences for biogenic silica dissolution

    PubMed Central

    Alfredsson, Hanna; Clymans, Wim; Stadmark, Johanna; Conley, Daniel; Rousk, Johannes

    2016-01-01

    We studied bacterial and fungal colonization of submerged plant litter, using a known Si-accumulator (Equisetum arvense), in experimental microcosms during one month. We specifically addressed the microbial decomposer role concerning biogenic silica (bSiO2) dissolution from the degrading litter. To vary the rates and level of microbial colonization, the litter was combined with a range of mineral nitrogen (N) and phosphorous (P) supplements. Overall microbial growth on plant litter increased with higher levels of N and P. There was a tendency for higher relative bacterial than fungal stimulation with higher nutrient levels. Differences in microbial colonization of litter between treatments allowed us to test how Si remineralization from plants was influenced by microbial litter decomposition. Contrary to previous results and expectations, we observed a general reduction in Si release from plant litter colonized by a microbial community, compared with sterile control treatments. This suggested that microbial growth resulted in a reduction of dissolved Si concentrations, and we discuss candidate mechanisms to explain this outcome. Hence, our results imply that the microbial role in plant litter associated Si turnover is different from that commonly assumed based on bSiO2 dissolution studies in aquatic ecosystems. PMID:26790464

  16. Bacterial and fungal colonization and decomposition of submerged plant litter: consequences for biogenic silica dissolution.

    PubMed

    Alfredsson, Hanna; Clymans, Wim; Stadmark, Johanna; Conley, Daniel; Rousk, Johannes

    2016-03-01

    We studied bacterial and fungal colonization of submerged plant litter, using a known Si-accumulator (Equisetum arvense), in experimental microcosms during one month. We specifically addressed the microbial decomposer role concerning biogenic silica (bSiO2) dissolution from the degrading litter. To vary the rates and level of microbial colonization, the litter was combined with a range of mineral nitrogen (N) and phosphorous (P) supplements. Overall microbial growth on plant litter increased with higher levels of N and P. There was a tendency for higher relative bacterial than fungal stimulation with higher nutrient levels. Differences in microbial colonization of litter between treatments allowed us to test how Si remineralization from plants was influenced by microbial litter decomposition. Contrary to previous results and expectations, we observed a general reduction in Si release from plant litter colonized by a microbial community, compared with sterile control treatments. This suggested that microbial growth resulted in a reduction of dissolved Si concentrations, and we discuss candidate mechanisms to explain this outcome. Hence, our results imply that the microbial role in plant litter associated Si turnover is different from that commonly assumed based on bSiO2 dissolution studies in aquatic ecosystems. PMID:26790464

  17. Plant water relations I: uptake and transport

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Plants, like all living things, are mostly water. Water is the matrix of life, and its availability determines the distribution and productivity of plants on earth. Vascular plants evolved structures that enable them to transport water long distances with little input of energy, but the hollow trach...

  18. Photoassisted decomposition of water over doped rutile electrodes

    NASA Astrophysics Data System (ADS)

    Giordano, N.; Antonucci, V.; Cavallaro, S.; Lembo, R.; Bart, J. C. J.

    The photoelectrolysis of water on a series of doped TiO2 semiconductors is presented. The TiO2 electrodes are prepared from 1 mm thick laminae of titanium, oxidized in an oven at 700 C for 4 h, and repeatedly impregnated in aqueous or acid (HCL) solutions containing equimolar (1M) quantities of TiCl3 and nitrates (or chlorides) of the dopant metal. The electrode current-voltage characteristics are measured in a one-compartment cell, using a 1 m Na 2SO4 solution. A 400 W medium pressure mercury lamp, emitting in the 310 to 1000 nm range, is used as a light source. Cell potentials are measured with an electrometer. An expression is derived for the energy conversion efficiency, which is strongly influenced by the preparation procedure. Pt-doping has the most marked positive influence and results in an energy conversion of 2.8 percent at 1 sun concentration, vs. 0.5 percent for an undoped sample. It is suggested that the best dopants, such as Pt, act through a reduction of the surface, thereby decreasing its acidity and increasing n-typeness.

  19. Accelerating the degradation of green plant waste with chemical decomposition agents.

    PubMed

    Kejun, Sun; Juntao, Zhang; Ying, Chen; Zongwen, Liao; Lin, Ruan; Cong, Liu

    2011-10-01

    Degradation of green plant waste is often difficult, and excess maturity times are typically required. In this study, we used lignin, cellulose and hemicellulose assays; scanning electron microscopy; infrared spectrum analysis and X-ray diffraction analysis to investigate the effects of chemical decomposition agents on the lignocellulose content of green plant waste, its structure and major functional groups and the mechanism of accelerated degradation. Our results showed that adding chemical decomposition agents to Ficus microcarpa var. pusillifolia sawdust reduced the contents of lignin by 0.53%-11.48% and the contents of cellulose by 2.86%-7.71%, and increased the contents of hemicellulose by 2.92%-33.63% after 24 h. With increasing quantities of alkaline residue and sodium lignosulphonate, the lignin content decreased. Scanning electron microscopy showed that, after F. microcarpa var. pusillifolia sawdust was treated with chemical decomposition agents, lignocellulose tube wall thickness increased significantlyIncreases of 29.41%, 3.53% and 34.71% were observed after treatment with NaOH, alkaline residue and sodium lignosulphonate, respectively. Infrared spectroscopy showed that CO and aromatic skeleton stretching absorption peaks were weakened and the C-H vibrational absorption peak from out-of-plane in positions 2 and 6 (S units) (890-900 cm(-1)) was strengthened after F. microcarpa var. pusillifolia sawdust was treated with chemical decomposition agents, indicating a reduction in lignin content. Several absorption peaks [i.e., C-H deformations (asymmetry in methyl groups, -CH(3)- and -CH(2)-) (1450-1460 cm(-1)); Aliphatic C-H stretching in methyl and phenol OH (1370-1380 cm(-1)); CO stretching (cellulose and hemicellulose) (1040-1060 cm(-1))] that indicate the presence of a chemical bond between lignin and cellulose was reduced, indicating that the chemical bond between lignin and cellulose had been partially broken. X-ray diffraction analysis showed that Na

  20. Decomposition of Phragmites australis rhizomes in artificial land-water transitional zones (ALWTZs) and management implications

    NASA Astrophysics Data System (ADS)

    Han, Zhen; Cui, Baoshan; Zhang, Yongtao

    2015-09-01

    Rhizomes are essential organs for growth and expansion of Phragmites australis. They function as an important source of organic matter and as a nutrient source, especially in the artificial land-water transitional zones (ALWTZs) of shallow lakes. In this study, decomposition experiments on 1- to 6-year-old P. australis rhizomes were conducted in the ALWTZ of Lake Baiyangdian to evaluate the contribution of the rhizomes to organic matter accumulation and nutrient release. Mass loss and changes in nutrient content were measured after 3, 7, 15, 30, 60, 90, 120, and 180 days. The decomposition process was modeled with a composite exponential model. The Pearson correlation analysis was used to analyze the relationships between mass loss and litter quality factors. A multiple stepwise regression model was utilized to determine the dominant factors that affect mass loss. Results showed that the decomposition rates in water were significantly higher than those in soil for 1- to 6-year-old rhizomes. However, the sequence of decomposition rates was identical in both water and soil. Significant relationships between mass loss and litter quality factors were observed at a later stage, and P-related factors proved to have a more significant impact than N-related factors on mass loss. According to multiple stepwise models, the C/P ratio was found to be the dominant factor affecting the mass loss in water, and the C/N and C/P ratios were the main factors affecting the mass loss in soil. The combined effects of harvesting, ditch broadening, and control of water depth should be considered for lake administrators.

  1. Quality assessment of plant transpiration water

    NASA Technical Reports Server (NTRS)

    Macler, Bruce A.; Janik, Daniel S.; Benson, Brian L.

    1990-01-01

    It has been proposed to use plants as elements of biologically-based life support systems for long-term space missions. Three roles have been brought forth for plants in this application: recycling of water, regeneration of air and production of food. This report discusses recycling of water and presents data from investigations of plant transpiration water quality. Aqueous nutrient solution was applied to several plant species and transpired water collected. The findings indicated that this water typically contained 0.3-6 ppm of total organic carbon, which meets hygiene water standards for NASA's space applications. It suggests that this method could be developed to achieve potable water standards.

  2. Plant inter-species effects on rhizosphere priming of soil organic matter decomposition

    NASA Astrophysics Data System (ADS)

    Pausch, Johanna; Zhu, Biao; Cheng, Weixin

    2015-04-01

    Living roots and their rhizodeposits can stimulate microbial activity and soil organic matter (SOM) decomposition up to several folds. This so-called rhizosphere priming effect (RPE) varies widely among plant species possibly due to species-specific differences in the quality and quantity of rhizodeposits and other root functions. However, whether the RPE is influenced by plant inter-species interactions remains largely unexplored, even though these interactions can fundamentally shape plant functions such as carbon allocation and nutrient uptake. In a 60-day greenhouse experiment, we continuously labeled monocultures and mixtures of sunflower, soybean and wheat with 13C-depleted CO2 and partitioned total CO2 efflux released from soil at two stages of plant development for SOM- and root-derived CO2. The RPE was calculated as the difference in SOM-derived CO2 between the planted and the unplanted soil, and was compared among the monocultures and mixtures. We found that the RPE was positive under all plants, ranging from 43% to 136% increase above the unplanted control. There were no significant differences in RPE at the vegetative stage. At the flowering stage however, the RPE in the soybean-wheat mixture was significantly higher than those in the sunflower monoculture, the sunflower-wheat mixture, and the sunflower-soybean mixture. These results indicated that the influence of plant inter-specific interactions on the RPE is case-specific and phenology-dependent. To evaluate the intensity of inter-specific effects on priming, we calculated an expected RPE for the mixtures based on the RPE of the monocultures weighted by their root biomass and compared it to the measured RPE under mixtures. At flowering, the measured RPE was significantly lower for the sunflower-wheat mixture than what can be expected from their monocultures, suggesting that RPE was significantly reduced by the inter-species effects of sunflower and wheat. In summary, our results clearly demonstrated

  3. Species and tissue type regulate long-term decomposition of brackish marsh plants grown under elevated CO2 conditions

    NASA Astrophysics Data System (ADS)

    Jones, Joshua A.; Cherry, Julia A.; McKee, Karen L.

    2016-02-01

    Organic matter accumulation, the net effect of plant production and decomposition, contributes to vertical soil accretion in coastal wetlands, thereby playing a key role in whether they keep pace with sea-level rise. Any factor that affects decomposition may affect wetland accretion, including atmospheric CO2 concentrations. Higher CO2 can influence decomposition rates by altering plant tissue chemistry or by causing shifts in plant species composition or biomass partitioning. A combined greenhouse-field experiment examined how elevated CO2 affected plant tissue chemistry and subsequent decomposition of above- and belowground tissues of two common brackish marsh species, Schoenoplectus americanus (C3) and Spartina patens (C4). Both species were grown in monoculture and in mixture under ambient (350-385 μL L-1) or elevated (ambient + 300 μL L-1) atmospheric CO2 conditions, with all other growth conditions held constant, for one growing season. Above- and belowground tissues produced under these treatments were decomposed under ambient field conditions in a brackish marsh in the Mississippi River Delta, USA. Elevated CO2 significantly reduced nitrogen content of S. americanus, but not sufficiently to affect subsequent decomposition. Instead, long-term decomposition (percent mass remaining after 280 d) was controlled by species composition and tissue type. Shoots of S. patens had more mass remaining (41 ± 2%) than those of S. americanus (12 ± 2%). Belowground material decomposed more slowly than that placed aboveground (62 ± 1% vs. 23 ± 3% mass remaining), but rates belowground did not differ between species. Increases in atmospheric CO2 concentration will likely have a greater effect on overall decomposition in this brackish marsh community through shifts in species dominance or biomass allocation than through effects on tissue chemistry. Consequent changes in organic matter accumulation may alter marsh capacity to accommodate sea-level rise through vertical

  4. MINI PILOT PLANT FOR DRINKING WATER RESEARCH

    EPA Science Inventory

    The Water Supply & Water Resources Division (WSWRD) has constructed 2 mini-pilot plant systems used to conduct drinking water research. These two systems each have 2 parallel trains for comparative research. The mini-pilot plants are small conventional drinking water treatment ...

  5. Decomposition of environmentally persistent perfluorooctanoic acid in water by photochemical approaches.

    PubMed

    Hori, Hisao; Hayakawa, Etsuko; Einaga, Hisahiro; Kutsuna, Shuzo; Koike, Kazuhide; Ibusuki, Takashi; Kiatagawa, Hiroshi; Arakawa, Ryuichi

    2004-11-15

    The decomposition of persistent and bioaccumulative perfluorooctanoic acid (PFOA) in water by UV-visible light irradiation, by H202 with UV-visible light irradiation, and by a tungstic heteropolyacid photocatalyst was examined to develop a technique to counteract stationary sources of PFOA. Direct photolysis proceeded slowly to produce CO2, F-, and short-chain perfluorocarboxylic acids. Compared to the direct photolysis, H2O2 was less effective in PFOA decomposition. On the other hand, the heteropolyacid photocatalyst led to efficient PFOA decomposition and the production of F- ions and CO2. The photocatalyst also suppressed the accumulation of short-chain perfluorocarboxylic acids in the reaction solution. PFOA in the concentrations of 0.34-3.35 mM, typical of those in wastewaters after an emulsifying process in fluoropolymer manufacture, was completely decomposed by the catalyst within 24 h of irradiation from a 200-W xenon-mercury lamp, with no accompanying catalyst degradation, permitting the catalyst to be reused in consecutive runs. Gas chromatography/mass spectrometry (GC/MS) measurements showed no trace of environmentally undesirable species such as CF4, which has a very high global-warming potential. When the (initial PFOA)/(initial catalyst) molar ratio was 10: 1, the turnover number for PFOA decomposition reached 4.33 over 24 h of irradiation. PMID:15573615

  6. Dynamics of zoomicrobial complexes upon decomposition of plant litter in spruce forests of the southern taiga

    NASA Astrophysics Data System (ADS)

    Rakhleeva, A. A.; Semenova, T. A.; Striganova, B. R.; Terekhova, V. A.

    2011-01-01

    Comparative studies of the composition and abundance of soil-dwelling invertebrates (microarthropods, nematodes, and testate amoebas) and micromycetes in the course of leaf and needle litter decomposition were conducted in two types of spruce forests on white-podzolic and brown forest soils in a field experiment. The analysis of the destruction dynamics has revealed a correlation between the rate of the litter mass loss and the abundance of microarthropods and testate amoebas in the decomposing plant residues. The highest amplitude of the seasonal fluctuations in the number of invertebrates was found for the micromycetes and nematodes as compared to that for the testate amoebas and microarthropods. In the complexes of micromycetes and invertebrates, changes in the dominants were revealed at the different stages of the decomposition. The litter's composition was found to be the main factor affecting the composition and abundance of the zoomicrobial complex of the destroyers. The type of biogeocenosis less influenced the abundance of pedobionts, but it determined their taxonomic composition to a greater extent. A significant inverse correlation was revealed between the number of micromycetes and that of small soil invertebrates.

  7. Water-Conserving Plant-Growth System

    NASA Technical Reports Server (NTRS)

    Dreschel, Thomas W.; Brown, Christopher S.

    1993-01-01

    Report presents further information about plant-growth apparatus described in "Tubular Membrane Plant-Growth Unit" (KSC-11375). Apparatus provides nutrient solution to roots of seedlings without flooding. Conserves water by helping to prevent evaporation from plant bed. Solution supplied only as utilized by seedlings. Device developed for supporting plant growth in space, also has applications for growing plants with minimum of water, such as in arid environments.

  8. Plant responses to water stress

    PubMed Central

    Kar, Rup Kumar

    2011-01-01

    Terrestrial plants most often encounter drought stress because of erratic rainfall which has become compounded due to present climatic changes.Responses of plants to water stress may be assigned as either injurious change or tolerance index. One of the primary and cardinal changes in response to drought stress is the generation of reactive oxygen species (ROS), which is being considered as the cause of cellular damage. However, recently a signaling role of such ROS in triggering the ROS scavenging system that may confer protection or tolerance against stress is emerging. Such scavenging system consists of antioxidant enzymes like SOD, catalase and peroxidases, and antioxidant compounds like ascorbate, reduced glutathione; a balance between ROS generation and scavenging ultimately determines the oxidative load. As revealed in case of defence against pathogen, signaling via ROS is initiated by NADPH oxidase-catalyzed superoxide generation in the apoplastic space (cell wall) followed by conversion to hydrogen peroxide by the activity of cell wall-localized SOD. Wall peroxidase may also play role in ROS generation for signaling. Hydrogen peroxide may use Ca2+ and MAPK pathway as downstream signaling cascade. Plant hormones associated with stress responses like ABA and ethylene play their role possibly via a cross talk with ROS towards stress tolerance, thus projecting a dual role of ROS under drought stress. PMID:22057331

  9. [Mixed-Spectral Spatial Information Decomposition Model of Water Hyperspectral Inversion].

    PubMed

    Pan, Bang-long; Wang, Xian-hua; Zhu, Jin; Yi, Wei-ning; Fang, Ting-yong

    2015-03-01

    The effect of Mixed-hyperspectral in the water is difficult in quantitative remote sensing of water. Studies have shown that the only scalar spectrum information is difficult to solve the problem of complex mixed spectra of water. Besides the spectral information, spatial distribution of information is one of the obvious characteristics of the broad waters pollution, and can be used as a useful complement to the remote sensing information and facilitate water complex spectral unmixing. Taking Chaohu as an example, the paper applies the HJ-1A HSI hyperspectral data and the supplemental surface spectral measurement data to discuss the mixed spectra of lake water by spatial statistics and genetic algorithm theory. By using the spatial variogram of geostatistics to simulate the distribution difference of two adjacent pixels, the space-informational decomposition model of mixed spectral in lake water is established by co-kriging genetic algorithm, which is a improved algorithm applying the spatial variogram function of neighborhood pixel as the constraint of the objective function of the genetic algorithm. Finally, the model inversion results of suspended matter concentration are verified. Compared with the conventional spectral unmixing model, the results show the correlation coefficient of the predicted and measured value of suspended sediment concentration is 0.82, the root mean square error 9.25 mg x L(-1) by mixed spectral space information decomposition model, so the correlation coefficient is increased by 8.9%, the root mean square error reduced by 2.78 mg x L(-1), indicating that the model of suspended matter concentration has a strong predictive ability. Therefore, the effective combination of spatial and spectral information of water, can avoid inversion result distortion due to weak spectral signal of water color parameters, and large amount of calculation of information extraction because of the high spectral band numbers, and also provides an effective way

  10. Decomposition of water Raman stretching band with a combination of optimization methods

    NASA Astrophysics Data System (ADS)

    Burikov, Sergey; Dolenko, Sergey; Dolenko, Tatiana; Patsaeva, Svetlana; Yuzhakov, Viktor

    2010-03-01

    In this study, an investigation of the behaviour of stretching bands of CH and OH groups of water-ethanol solutions at alcohol concentrations ranging from 0 to 96% by volume has been performed. A new approach to decomposition of the wide structureless water Raman band into spectral components based on modern mathematical methods of solution of inverse multi-parameter problems-combination of Genetic Algorithm and the method of Generalized Reduced Gradient-has been demonstrated. Application of this approach to decomposition of Raman stretching bands of water-ethanol solutions allowed obtaining new interesting results practically without a priori information. The behaviour of resolved spectral components of Raman stretching OH band in binary mixture with rising ethanol concentration is in a good agreement with the concept of clathrate-like structure of water-ethanol solutions. The results presented in this paper confirm existence of essential structural rearrangement in water-ethanol solutions at ethanol concentrations 20-30% by volume.

  11. Wetlands: water, wildlife, plants, & people

    USGS Publications Warehouse

    Vandas, Stephen; Farrar, Frank, (artist)

    1996-01-01

    Wetlands are part of all our lives. They can generally be described as transitional areas between land and deepwater habitats. There are many different kinds of wetlands, and they can be found in many different habitat types, from forests to deserts; some are maintained by saltwater, others by freshwater. This poster shows general types of diverse wetlands and demonstrates how people and wetlands can benefit by living together. The diversity of plants and animals is shown in cartooned pictures. As with plants and animals, there are many different common names for the various wetland types. The common names used on this poster were used by the U.S. Fish and Wildlife Service in the publication "Wetlands-Status and Trends in the Conterminous United States, Mid-1970's to Mid-1980's." Estuarine wetland types--salt marshes and mangrove swamps--are labeled in red letters. The estuary is where ocean saltwater and river freshwater mix. The estuary is labeled in orange letters. The inland wetland types-inland marshes and wet meadows, forested wetlands, and shrub wetlands-are labeled in yellow. Other wetlands are present in rivers, lakes, and reservoirs. The water bodies associated with these wetlands are labeled in black. The poster is folded into 8.5" x 11" panels; front and back panels can easily be photocopied.

  12. The Dynamics of Plant Cell-Wall Polysaccharide Decomposition in Leaf-Cutting Ant Fungus Gardens

    PubMed Central

    Harholt, Jesper; Willats, William G. T.; Boomsma, Jacobus J.

    2011-01-01

    The degradation of live plant biomass in fungus gardens of leaf-cutting ants is poorly characterised but fundamental for understanding the mutual advantages and efficiency of this obligate nutritional symbiosis. Controversies about the extent to which the garden-symbiont Leucocoprinus gongylophorus degrades cellulose have hampered our understanding of the selection forces that induced large scale herbivory and of the ensuing ecological footprint of these ants. Here we use a recently established technique, based on polysaccharide microarrays probed with antibodies and carbohydrate binding modules, to map the occurrence of cell wall polymers in consecutive sections of the fungus garden of the leaf-cutting ant Acromyrmex echinatior. We show that pectin, xyloglucan and some xylan epitopes are degraded, whereas more highly substituted xylan and cellulose epitopes remain as residuals in the waste material that the ants remove from their fungus garden. These results demonstrate that biomass entering leaf-cutting ant fungus gardens is only partially utilized and explain why disproportionally large amounts of plant material are needed to sustain colony growth. They also explain why substantial communities of microbial and invertebrate symbionts have evolved associations with the dump material from leaf-cutting ant nests, to exploit decomposition niches that the ant garden-fungus does not utilize. Our approach thus provides detailed insight into the nutritional benefits and shortcomings associated with fungus-farming in ants. PMID:21423735

  13. Dynamics of microbial communities during decomposition of litter from pioneering plants in initial soil ecosystems

    NASA Astrophysics Data System (ADS)

    Esperschütz, J.; Zimmermann, C.; Dümig, A.; Welzl, G.; Buegger, F.; Elmer, M.; Munch, J. C.; Schloter, M.

    2012-10-01

    In initial ecosystems concentrations of all macro- and micronutrients can be considered as extremely low. Plant litter therefore strongly influences the development of a degraders' food web and is an important source for C and N input into soil in such ecosystems. In the present study, a 13C litter decomposition field experiment was performed for 30 weeks in initial soils from a post-mining area near the city of Cottbus (Germany). Two of this regions' dominant but contrasting pioneering plant species (Lotus corniculatus L. and Calamagrostis epigejos L.) were chosen to investigate the effects of litter quality on the litter decomposing microbial food web in initially nutrient-poor substrates. The results clearly indicate the importance of litter quality, mainly the amount of N stored in the litter material and its bioavailability for the degradation process and the development of microbial communities in the detritusphere and bulk soil. Whereas the degradation process of the L. corniculatus litter which had a low C/N ratio was fast and most pronounced changes in the microbial community structure were observed 1-4 weeks after litter addition, the degradation of the C. epigejos litter material was slow and microbial community changes mainly occurred at between 4 and 30 weeks after litter addition to the soil. However for both litter materials a clear indication for the importance of fungi for the degradation process was observed both on the abundance level as well as on the level of 13C incorporation (activity).

  14. Dynamics of microbial communities during decomposition of litter from pioneering plants in initial soil ecosystems

    NASA Astrophysics Data System (ADS)

    Esperschütz, J.; Zimmermann, C.; Dümig, A.; Welzl, G.; Buegger, F.; Elmer, M.; Munch, J. C.; Schloter, M.

    2013-07-01

    In initial ecosystems, concentrations of all macro- and micronutrients can be considered as extremely low. Plant litter therefore strongly influences the development of a degrader's food web and is an important source for C and N input into soil in such ecosystems. In the present study, a 13C litter decomposition field experiment was performed for 30 weeks in initial soils from a post-mining area near the city of Cottbus (Germany). Two of this region's dominant but contrasting pioneering plant species (Lotus corniculatus L. and Calamagrostis epigejos L.) were chosen to investigate the effects of litter quality on the litter decomposing microbial food web in initially nutrient-poor substrates. The results clearly indicate the importance of litter quality, as indicated by its N content, its bioavailability for the degradation process and the development of microbial communities in the detritusphere and soil. The degradation of the L. corniculatus litter, which had a low C / N ratio, was fast and showed pronounced changes in the microbial community structure 1-4 weeks after litter addition. The degradation of the C. epigejos litter material was slow and microbial community changes mainly occurred between 4 and 30 weeks after litter addition to the soil. However, for both litter materials a clear indication of the importance of fungi for the degradation process was observed both in terms of fungal abundance and activity (13C incorporation activity)

  15. Changes in bacterial and eukaryotic communities during sewage decomposition in Mississippi river water.

    PubMed

    Korajkic, Asja; Parfrey, Laura Wegener; McMinn, Brian R; Baeza, Yoshiki Vazquez; VanTeuren, Will; Knight, Rob; Shanks, Orin C

    2015-02-01

    Microbial decay processes are one of the mechanisms whereby sewage contamination is reduced in the environment. This decomposition process involves a highly complex array of bacterial and eukaryotic communities from both sewage and ambient waters. However, relatively little is known about how these communities change due to mixing and subsequent decomposition of the sewage contaminant. We investigated decay of sewage in upper Mississippi River using Illumina sequencing of 16S and 18S rRNA gene hypervariable regions and qPCR for human-associated and general fecal Bacteroidales indicators. Mixtures of primary treated sewage and river water were placed in dialysis bags and incubated in situ under ambient conditions for seven days. We assessed changes in microbial community composition under two treatments in a replicated factorial design: sunlight exposure versus shaded and presence versus absence of native river microbiota. Initial diversity was higher in sewage compared to river water for 16S sequences, but the reverse was observed for 18S sequences. Both treatments significantly shifted community composition for eukaryotes and bacteria (P < 0.05). Data indicated that the presence of native river microbiota, rather than exposure to sunlight, accounted for the majority of variation between treatments for both 16S (R = 0.50; P > 0.001) and 18S (R = 0.91; P = 0.001) communities. A comparison of 16S sequence data and fecal indicator qPCR measurements indicated that the latter was a good predictor of overall bacterial community change over time (rho: 0.804-0.814, P = 0.001). These findings suggest that biotic interactions, such as predation by bacterivorous protozoa, can be critical factors in the decomposition of sewage in freshwater habitats and support the use of Bacteroidales genetic markers as indicators of fecal pollution. PMID:25463929

  16. Spinodal decomposition of the three-component microemulsion system: AOT/water/decane

    SciTech Connect

    Mallamace, F.; Micali, N.; Trusso, S.; Chen, S.H.

    1995-12-31

    The authors have performed a series of spinodal decomposition measurements of a three-component microemulsion system made of a surfactant AOT, water, and decane. The measurements were made by a temperature jump from a one-phase droplet microemulsion to a two-phase droplet microemulsion along the critical iso-volume fraction line (10%) using the time resolved light scattering intensity technique. All three stages of the evolution were studied. The typical scattering intensity distribution is in good agreement with recent dynamic scaling theories.

  17. Water protection in coke-plant design

    SciTech Connect

    G.I. Alekseev

    2009-07-15

    Wastewater generation, water consumption, and water management at coke plants are considered. Measures to create runoff-free water-supply and sewer systems are discussed. Filters for water purification, corrosion inhibitors, and biocides are described. An integrated single-phase technology for the removal of phenols, thiocyanides, and ammoniacal nitrogen is outlined.

  18. Water Treatment Technology - General Plant Operation.

    ERIC Educational Resources Information Center

    Ross-Harrington, Melinda; Kincaid, G. David

    One of twelve water treatment technology units, this student manual on general plant operations provides instructional materials for seven competencies. (The twelve units are designed for a continuing education training course for public water supply operators.) The competencies focus on the following areas: water supply regulations, water plant…

  19. Plant traits and decomposition: are the relationships for roots comparable to those for leaves?

    PubMed Central

    Birouste, Marine; Kazakou, Elena; Blanchard, Alain; Roumet, Catherine

    2012-01-01

    Background and Aims Fine root decomposition is an important determinant of nutrient and carbon cycling in grasslands; however, little is known about the factors controlling root decomposition among species. Our aim was to investigate whether interspecific variation in the potential decomposition rate of fine roots could be accounted for by root chemical and morphological traits, life history and taxonomic affiliation. We also investigated the co-ordinated variation in root and leaf traits and potential decomposition rates. Methods We analysed potential decomposition rates and the chemical and morphological traits of fine roots on 18 Mediterranean herbaceous species grown in controlled conditions. The results were compared with those obtained for leaves in a previous study conducted on similar species. Key Results Differences in the potential decomposition rates of fine roots between species were accounted for by root chemical composition, but not by morphological traits. The root potential decomposition rate varied with taxonomy, but not with life history. Poaceae, with high cellulose concentration and low concentrations of soluble compounds and phosphorus, decomposed more slowly than Asteraceae and Fabaceae. Patterns of root traits, including decomposition rate, mirrored those of leaf traits, resulting in a similar species clustering. Conclusions The highly co-ordinated variation of roots and leaves in terms of traits and potential decomposition rate suggests that changes in the functional composition of communities in response to anthropogenic changes will strongly affect biogeochemical cycles at the ecosystem level. PMID:22143881

  20. Regulation of Water in Plant Cells

    ERIC Educational Resources Information Center

    Kowles, Richard V.

    2010-01-01

    Cell water relationships are important topics to be included in cell biology courses. Differences exist in the control of water relationships in plant cells relative to control in animal cells. One important reason for these differences is that turgor pressure is a consideration in plant cells. Diffusion and osmosis are the underlying factors…

  1. Interaction of position, litter type, and water pulses on decomposition of grasses from the semiarid Patagonian steppe.

    PubMed

    Austin, Amy T; Araujo, Patricia I; Leva, Paula E

    2009-09-01

    Litter lignin and nutrient content, annual rainfall, and biotic activity are not good predictors of litter decomposition in arid and semiarid ecosystems, suggesting that other factors may be important in controlling carbon turnover. We explored the relative importance of litter position (above- vs. belowground), litter type (leaf vs. root), and pulsed water events (large vs. small) on mass loss with grass species of the semiarid Patagonian steppe. In a factorial experiment of mesocosms, we incubated leaf and root litter simultaneously above- and belowground and manipulated water availability with large and small pulses. Significant interactions between position and litter type and position and pulse sizes demonstrated interactive controls on organic mass loss. Aboveground decomposition showed no response to pulse size or litter type, as roots and leaves decomposed equally rapidly under all circumstances. In contrast, belowground decomposition was significantly altered by litter type and water pulses, with roots decomposing significantly slower and small water pulses reducing belowground decomposition. The results of this mesocosm experiment support the idea that controls other than water availability may dominate aboveground mass loss, while a combination of recalcitrant litter and water penetration in the soil profile are critical factors determining belowground decomposition, which is ultimately mediated by biotic degradation. PMID:19769141

  2. Species and tissue type regulate long-term decomposition of brackish marsh plants grown under elevated CO2 conditions

    USGS Publications Warehouse

    Jones, Joshua A; Cherry, Julia A; Mckee, Karen L.

    2016-01-01

    Organic matter accumulation, the net effect of plant production and decomposition, contributes to vertical soil accretion in coastal wetlands, thereby playing a key role in whether they keep pace with sea-level rise. Any factor that affects decomposition may affect wetland accretion, including atmospheric CO2 concentrations. Higher CO2 can influence decomposition rates by altering plant tissue chemistry or by causing shifts in plant species composition or biomass partitioning. A combined greenhouse-field experiment examined how elevated CO2 affected plant tissue chemistry and subsequent decomposition of above- and belowground tissues of two common brackish marsh species, Schoenoplectus americanus (C3) and Spartina patens (C4). Both species were grown in monoculture and in mixture under ambient (350-385 μL L-1) or elevated (ambient + 300 μL L-1) atmospheric CO2 conditions, with all other growth conditions held constant, for one growing season. Above- and belowground tissues produced under these treatments were decomposed under ambient field conditions in a brackish marsh in the Mississippi River Delta, USA. Elevated CO2 significantly reduced nitrogen content of S. americanus, but not sufficiently to affect subsequent decomposition. Instead, long-term decomposition (percent mass remaining after 280 d) was controlled by species composition and tissue type. Shoots of S. patens had more mass remaining (41 ± 2%) than those of S. americanus (12 ± 2 %). Belowground material decomposed more slowly than that placed aboveground (62 ± 1% vs. 23 ± 3% mass remaining), but rates belowground did not differ between species. Increases in atmospheric CO2concentration will likely have a greater effect on overall decomposition in this brackish marsh community through shifts in species dominance or biomass allocation than through effects on tissue chemistry. Consequent changes in organic matter accumulation may alter marsh capacity to accommodate sea-level rise

  3. Spectral scaling of hydrochemical responses - decomposition of water quality time series

    NASA Astrophysics Data System (ADS)

    Riml, Joakim; Wörman, Anders

    2016-04-01

    Knowledge of the different processes affecting the biogeochemical cycling of compounds transported with water, such as nutrients, contaminants and different forms of organically and inorganically bound carbon, is fundamental for understanding and assessing the water quality of any given surface water systems. However, these governing processes are often difficult to quantify, partly due to the complex dynamics of the governing physical and biogeochemical mechanisms, which span over a wide range of temporal and spatial scales. Here we present a recently developed analytical technique that separates the spectrum of time scales in a physically based transport model by relating the fluctuations in the forcing boundary conditions (i.e. the load function) to the water quality response. By transforming the transport problem from the time domain into the frequency domain, closed-form solutions were obtained and used to derive compound specific formal expressions of the power spectral response for different hydrological systems including both a single stream reach and a network of interconnected transport pathways. The frequency dependent response, defined as the spectral scaling function, was subsequently used to evaluate concentration time series of water quality parameters on different spatial scales. This spectral decomposition attributes the water quality response in specific intervals of frequencies to governing processes and provides an opportunity to investigate/quantify the competing processes affecting the different compounds important for the water quality response.

  4. Effects of polyacrylamide, biopolymer, and biochar on decomposition of soil organic matter and 14C-labeled plant residues as determined by enzyme activities

    NASA Astrophysics Data System (ADS)

    Mahmoud Awad, Yasser; Ok, Young Sik; Kuzyakov, Yakov

    2014-05-01

    Application of polymers for the improvement of aggregate structure and reduction of soil erosion may alter the availability and decomposition of plant residues. In this study, we assessed the effects of anionic polyacrylamide (PAM), synthesized biopolymer (BP), and biochar (BC) on the decomposition of 14C-labeled maize residue in sandy and sandy loam soils. Specifically, PAM and BP with or without 14C-labeled plant residue were applied at 400 kg ha-1, whereas BC was applied at 5000 kg ha-1, after which the soils were incubated for 80 days at 22 oC. Initially, plant residue decomposition was much higher in untreated sandy loam soil than in sandy soil. Nevertheless, the stimulating effects of BP and BC on the decomposition of plant residue were more pronounced in sandy soil, where it accounted for 13.4% and 23.4% of 14C input, respectively, whereas in sandy loam soil, the acceleration of plant residue decomposition by BP and BC did not exceed 2.6% and 14.1%, respectively, compared to untreated soil with plant residue. The stimulating effects of BP and BC on the decomposition of plant residue were confirmed based on activities of β-cellobiohydrolase, β-glucosidase, and chitinase in both soils. In contrast to BC and BP, PAM did not increase the decomposition of native or added C in both soils.

  5. Radiation-induced decomposition of trace amounts of 17 β-estradiol in water

    NASA Astrophysics Data System (ADS)

    Kimura, Atsushi; Taguchi, Mitsumasa; Arai, Hidehiko; Hiratsuka, Hiroshi; Namba, Hideki; Kojima, Takuji

    2004-03-01

    The radiation-induced decomposition of trace amounts of 17 β-estradiol (E2) in water was studied as a function of the dose of 60Co γ-rays. The rate constant of the reaction of the OH radicals with E2 was estimated to be 1.6×10 10 mol dm -3 s -1 by a comparison with the known rate constant for the reaction with phenol. Both E2 and E2-equivalent concentrations were estimated by LC-MS and ELISA, and decreased with an increase in γ-rays dose. E2 (1.8 nmol dm -3) in water was degraded almost completely by irradiations up to 10 Gy. The estrogen activity of the same sample solution still remained at a dose of 10 Gy, but decreased at 30 Gy to the lower than the threshold level of contamination to induce some estrogenic effects on the environmental ecology.

  6. A Trip to the Water Plant.

    ERIC Educational Resources Information Center

    Laskey, Marilyn

    Produced for primary and intermediate grades, this student booklet provides a study of where water comes from, how we get clean water, and the operations of a water treatment plant. Photographs, a few line drawings, a minimum of narrative, and a glossary of terms make up its content. A related document is the teacher's guide, SE 016 490. This work…

  7. Influence of water potential on decomposition of soil organic matter in high elevation meadows

    NASA Astrophysics Data System (ADS)

    Arnold, C. L.; Ghezzehei, T. A.; Berhe, A.

    2013-12-01

    High elevation meadows of the Sierra Nevada, California are defined by the presence of a high water table throughout the growing season. This definition takes into account the natural drawdown of most meadow systems during the summer months to within a few feet of the surface. The cyclic drawdown/recharge of the meadow water table, as well as local hydrologic gradient that exists in most meadow systems (ranging from xeric to hydric) impose important controls on organic matter storage and decomposition in these systems. In this study we incubated soils from the xeric, mesic and hydric regions of a subalpine Sierra Nevada meadow at five different water potentials and measured the CO2 flux at intervals over one year. We found that the cumulative carbon mineralization was greatest at the lowest (0.1 bar) and highest (4 bar) water potentials, across all regions of the meadow, suggesting a microbial response threshold that is reached as the soil dries. Soils from the hydric meadow regions showed the largest response to extreme drying of the soil. These results highlight the importance of soil moisture in regulating soil respiration in these systems and different levels of microbial activity when these soils are wet vs. dry. While normal conditions in these systems keep water potentials low (< 0.2 bar), future drought conditions can potentially increase the level of dryness in the meadows to the point where rapid carbon loss can be expected.

  8. Aquatic Plant Water Quality Criteria

    EPA Science Inventory

    The USEPA, as stated in the Clean Water Act, is tasked with developing numerical Aquatic Life Critiera for various pollutants found in the waters of the United States. These criteria serve as guidance for States and Tribes to use in developing their water quality standards. The G...

  9. Stability of Supported Platinum Sulfuric Acid Decomposition Catalysts for use in Thermochemical Water Splitting Cycles

    SciTech Connect

    Daniel M. Ginosar; Lucia M. Petkovic; Anne W. Glenn; Kyle C. Burch

    2007-03-01

    The activity and stability of several metal oxide supported platinum catalysts were explored for the sulfuric acid decomposition reaction. The acid decomposition reaction is common to several sulfur based thermochemical water splitting cycles. Reactions were carried out using a feed of concentrated liquid sulfuric acid (96 wt%) at atmospheric pressure at temperatures between 800 and 850 °C and a weight hour space velocity of 52 g acid/g catalyst/hr. Reactions were run at these high space velocities such that variations in kinetics were not masked by surplus catalyst. The influence of exposure to reaction conditions was explored for three catalysts; 0.1-0.2 wt% Pt supported on alumina, zirconia and titania. The higher surface area Pt/Al2O3 and Pt/ZrO2 catalysts were found to have the highest activity but deactivated rapidly. A low surface area Pt/TiO2 catalyst was found to have good stability in short term tests, but slowly lost activity for over 200 hours of continuous operation.

  10. CHROMOPHORIC DISSOLVED ORGANIC MATTER (CDOM) DERIVED FROM DECOMPOSITION OF VARIOUS VASCULAR PLANT AND ALGAL SOURCES

    EPA Science Inventory

    Chromophoric dissolved organic (CDOM) in aquatic environments is derived from the microbial decomposition of terrestrial and microbial organic matter. Here we present results of studies of the spectral properties and photoreactivity of the CDOM derived from several organic matter...

  11. Examining an underappreciated control on lignin decomposition in soils? Effects of reactive manganese species on intact plant cell walls

    NASA Astrophysics Data System (ADS)

    Keiluweit, M.; Bougoure, J.; Pett-Ridge, J.; Kleber, M.; Nico, P. S.

    2011-12-01

    Lignin comprises a dominant proportion of carbon fluxes into the soil (representing up to 50% of plant litter and roots). Two lines of evidence suggest that manganese (Mn) acts as a strong controlling factor on the residence time of lignin in soil ecosystems. First, Mn content is highly correlated with litter decomposition in temperate and boreal forest soil ecosystems and, second, microbial agents of lignin degradation have been reported to rely on reactive Mn(III)-complexes to specifically oxidize lignin. However, few attempts have been made to isolate the mechanisms responsible for the apparent Mn-dependence of lignin decomposition in soils. Here we tested the hypothesis that Mn(III)-oxalate complexes may act as a perforating 'pretreatment' for structurally intact plant cell walls. We propose that these diffusible oxidizers are small enough to penetrate and react with non-porous ligno-cellulose in cell walls. This process was investigated by reacting single Zinnia elegans tracheary elements with Mn(III)-oxalate complexes in a continuous flow-through microreactor. The uniformity of cultured tracheary elements allowed us to examine Mn(III)-induced changes in cell wall chemistry and ultrastructure on the micro-scale using fluorescence and electron microscopy as well as synchrotron-based infrared and X-ray spectromicroscopy. Our results show that Mn(III)-complexes substantially oxidize specific lignin components of the cell wall, solubilize decomposition products, severely undermine the cell wall integrity, and cause cell lysis. We conclude that Mn(III)-complexes induce oxidative damage in plant cell walls that renders ligno-cellulose substrates more accessible for microbial lignin- and cellulose-decomposing enzymes. Implications of our results for the rate limiting impact of soil Mn speciation and availability on litter decomposition in forest soils will be discussed.

  12. Succession of Phylogeny and Function During Plant Litter Decomposition (2013 DOE JGI Genomics of Energy and Environment 8th Annual User Meeting)

    SciTech Connect

    Brodie, Eoin

    2013-03-01

    Eoin Brodie of Berkeley Lab on "Succession of phylogeny and function during plant litter decomposition" at the 8th Annual Genomics of Energy & Environment Meeting on March 27, 2013 in Walnut Creek, Calif.

  13. Hydroelectric plant integrated with foul waters

    NASA Astrophysics Data System (ADS)

    Fragiacomo, P.; Scornaienchi, N. M.

    2005-09-01

    The foul water plant, the object of this work, involves the energy exploitation of the waters from two torrents and the foul water of a town in Southern Italy. The plant layout is such that it enables, moreover, the use of the same hydraulic works to supply irrigation water in the summer to farmers who work near the proposed mini-power station. With the aim of also carrying out an economic financial evaluation, the technical choices have been economically quantified and the outcome of these analyses have provided positive indications.

  14. Spatial Decomposition of Translational Water-Water Correlation Entropy in Binding Pockets.

    PubMed

    Nguyen, Crystal N; Kurtzman, Tom; Gilson, Michael K

    2016-01-12

    A number of computational tools available today compute the thermodynamic properties of water at surfaces and in binding pockets by using inhomogeneous solvation theory (IST) to analyze explicit-solvent simulations. Such methods enable qualitative spatial mappings of both energy and entropy around a solute of interest and can also be applied quantitatively. However, the entropy estimates of existing methods have, to date, been almost entirely limited to the first-order terms in the IST's entropy expansion. These first-order terms account for localization and orientation of water molecules in the field of the solute but not for the modification of water-water correlations by the solute. Here, we present an extension of the Grid Inhomogeneous Solvation Theory (GIST) approach which accounts for water-water translational correlations. The method involves rewriting the two-point density of water in terms of a conditional density and utilizes the efficient nearest-neighbor entropy estimation approach. Spatial maps of this second order term, for water in and around the synthetic host cucurbit[7]uril and in the binding pocket of the enzyme Factor Xa, reveal mainly negative contributions, indicating solute-induced water-water correlations relative to bulk water; particularly strong signals are obtained for sites at the entrances of cavities or pockets. This second-order term thus enters with the same, negative, sign as the first order translational and orientational terms. Numerical and convergence properties of the methodology are examined. PMID:26636620

  15. Water/Wastewater Treatment Plant Operator Qualifications.

    ERIC Educational Resources Information Center

    Water and Sewage Works, 1979

    1979-01-01

    This article summarizes in tabular form the U.S. and Canadian programs for classification of water and wastewater treatment plant personnel. Included are main characteristics of the programs, educational and experience requirements, and indications of requirement substitutions. (CS)

  16. Spinodal decomposition of a three-component water-in-oil microemulsion system

    SciTech Connect

    Mallamace, F.; Micali, N.; Trusso, S.; Chen, S.H. ||

    1995-06-01

    We have performed a series of spinodal decomposition measurements of a three-component microemulsion system made of a surfactant Aerosol OT, water, and decane. The measurements were made by a temperature jump from a one-phase droplet microemulsion to a two-phase droplet microemulsion along the critical isovolume fraction line (10%) using a time resolved light scattering intensity measurement technique. All three stages of the evolution were studied. Time evolution of intensities for the initial stage follows closely the linearized theory. On the other hand, time evolution of the characteristic wave vector, the maximum scattering intensity, and the intensity distributions in the intermediate and late stages are in good agreement with recent dynamic scaling theories.

  17. Effect of Oxygen Gas on the Decomposition of Dye by Pulsed Discharge in Water Droplet Spray

    NASA Astrophysics Data System (ADS)

    Nose, Taisuke; Yokoyama, Yuzo; Nakamura, Akira; Minamitani, Yasushi

    Effect of O2 on the decolorization of indigo carmine and on the production of dissolved species such as NO2-, NO3-, O3 and H2O2 in the treatment water by pulsed discharge in water droplet spray was investigated by controlling the O2/N2 ratios as carrier gases in the reactor. The decolorization rate gradually increased with rise in O2 ratio, which reached a constant value in the range of 50% to 90% O2 ratio and decreased in pure O2. The maximum value was about 2 times as high as that of 20% O2 ratio. The decolorization efficiency was not affected by gas flow rate in the range of 4 L/min to 50 L/min. NO2- in the treatment water was only detected in pure N2, but NO3- was produced in O2/N2. NO2- added to the treatment water was not oxidized in pure N2, but was perfectly converted to NO3- in O2/N2. These results implied that hydroxyl radical produced in gas phase does not directly contribute to the oxidation of substances in water. O3 concentration gradually increased with rise in O2 ratio, whereas H2O2 concentration decreased. In the range of 50 to 80% O2 ratio, O3 and H2O2 concentrations were approximately constant value, similar to the trend of decolorization rate. Moreover rate constants on various gas mixing ratio of O2/N2 were determined from the kinetics study. These results suggested that hydroxyl radical produced in the treatment water by the chain reactions of O3 and hydroperoxy radical (HO2·) plays an important role of the decomposition of molecules in water.

  18. Water management and productivity in planted forests

    NASA Astrophysics Data System (ADS)

    Nettles, J. E.

    2014-09-01

    As climate variability endangers water security in many parts of the world, maximizing the carbon balance of plantation forestry is of global importance. High plant water use efficiency is generally associated with lower plant productivity, so an explicit balance in resources is necessary to optimize water yield and tree growth. This balance requires predicting plant water use under different soil, climate, and planting conditions, as well as a mechanism to account for trade-offs in ecosystem services. Several strategies for reducing the water use of forests have been published but there is little research tying these to operational forestry. Using data from silvicultural and biofuel feedstock research in pine plantation ownership in the southeastern USA, proposed water management tools were evaluated against known treatment responses to estimate water yield, forest productivity, and economic outcomes. Ecosystem impacts were considered qualitatively and related to water use metrics. This work is an attempt to measure and compare important variables to make sound decisions about plantations and water use.

  19. The catalytic decomposition of silver coated cinnamyl alcohol during water exposure and the formation of silver nanoparticles

    NASA Astrophysics Data System (ADS)

    Dahle, S.; Höfft, O.; Viöl, W.; Maus-Friedrichs, W.

    2014-03-01

    Metastable Induced Electron Spectroscopy, Ultraviolet Photoelectron Spectroscopy (He I), X-ray Photoelectron Spectroscopy, and Quadrupole Mass Spectrometry are employed to study the interaction of water with Ag nanoparticles on cinnamyl alcohol films. The films have been prepared on Au(111) substrates by thermal evaporation. The water adsorption does not result in any chemical interaction with the silver nanoparticles at all, but the cinnamyl alcohol changes its chemical structure significantly. While water molecules induce a reduction of the organic groups, the film thickness seems to decrease. Thus, a decomposition of the cinnamyl alcohol films is proposed. Since no effects are observed during water interaction with pure cinnamyl alcohol films at all, a catalytic reaction appears to take place. No decomposition is found for cinnamyl alcohol adsorbed on a closed silver film, indicating that Ag nanoparticles are required for this catalytical decomposition. The MIES and UPS spectra indicate the existence of a closed metallic film directly after silver adsorption on cinnamyl alcohol, while they suggest the presence of silver nanoparticles after the exposure to water. The formation of silver nanoparticles therefore seems to happen concurrently to the catalytic decomposition of cinnamyl alcohol.

  20. Labile compounds in plant litter reduce the sensitivity of decomposition to warming and altered precipitation.

    PubMed

    Suseela, Vidya; Tharayil, Nishanth; Xing, Baoshan; Dukes, Jeffrey S

    2013-10-01

    Together, climate and litter quality strongly regulate decomposition rates. Although these two factors and their interaction have been studied across species in continent-scale experiments, few researchers have studied how labile and recalcitrant compounds interact to influence decomposition, or the climate sensitivity of decomposition, within a litter type. Over a period of 3 yr, we studied the effects of warming and altered precipitation on mass loss and compound-specific decomposition using two litter types that possessed similar heteropolymer chemistry, but different proportions of labile and recalcitrant compounds. Climate treatments immediately affected the mass loss of the more recalcitrant litter, but affected the more labile litter only after 2 yr. After 3 yr, although both litter types had lost similar amounts of mass, warming (c. 4°C) and supplemental precipitation (150% of ambient) together accelerated the degradation of alkyl-carbon and lignin only in the more recalcitrant litter, highlighting the role of initial litter quality in determining whether the chemistry of litter residues converges or diverges under different climates. Our finding that labile compounds in litter reduce the climate sensitivity of mass loss and the decomposition of recalcitrant matrix is novel. Our results highlight the potential for litter quality to regulate the effect of climatic changes on the sequestration of litter-derived carbon. PMID:23822593

  1. Continuous Monitoring of Plant Water Potential

    PubMed Central

    Schaefer, Nick L.; Trickett, Edward S.; Ceresa, Anthony; Barrs, Henry D.

    1986-01-01

    Plant water potential was monitored continuously with a Wescor HR-33T dewpoint hygrometer in conjunction with a L51 chamber. This commercial instrument was modified by replacing the AC-DC mains power converter with one stabilized by zener diode controlled transistors. The thermocouple sensor and electrical lead needed to be thermally insulated to prevent spurious signals. For rapid response and faithful tracking a low resistance for water vapor movement between leaf and sensor had to be provided. This could be effected by removing the epidermis either by peeling or abrasion with fine carborundum cloth. A variety of rapid plant water potential responses to external stimuli could be followed in a range of crop plants (sunflower (Helianthus annuus L., var. Hysun 30); safflower (Carthamus tinctorious L., var. Gila); soybean (Glycine max L., var. Clark); wheat (Triticum aestivum L., var. Egret). These included light dark changes, leaf excision, applied pressure to or anaerobiosis of the root system. Water uptake by the plant (safflower, soybean) mirrored that for water potential changes including times when plant water status (soybean) was undergoing cyclical changes. PMID:16664805

  2. Continuous monitoring of plant water potential.

    PubMed

    Schaefer, N L; Trickett, E S; Ceresa, A; Barrs, H D

    1986-05-01

    Plant water potential was monitored continuously with a Wescor HR-33T dewpoint hygrometer in conjunction with a L51 chamber. This commercial instrument was modified by replacing the AC-DC mains power converter with one stabilized by zener diode controlled transistors. The thermocouple sensor and electrical lead needed to be thermally insulated to prevent spurious signals. For rapid response and faithful tracking a low resistance for water vapor movement between leaf and sensor had to be provided. This could be effected by removing the epidermis either by peeling or abrasion with fine carborundum cloth. A variety of rapid plant water potential responses to external stimuli could be followed in a range of crop plants (sunflower (Helianthus annuus L., var. Hysun 30); safflower (Carthamus tinctorious L., var. Gila); soybean (Glycine max L., var. Clark); wheat (Triticum aestivum L., var. Egret). These included light dark changes, leaf excision, applied pressure to or anaerobiosis of the root system. Water uptake by the plant (safflower, soybean) mirrored that for water potential changes including times when plant water status (soybean) was undergoing cyclical changes. PMID:16664805

  3. Suppressing NOM access to controlled porous TiO2 particles enhances the decomposition of target water contaminants

    EPA Science Inventory

    Suppressing access of natural organic matter (NOM) to TiO2 is a key to the successful photocatalytic decomposition of a target contaminant in water. This study first demonstrates simply controlling the porous structure of TiO2 can significantly improve the selective oxidation.

  4. Organic carbon decomposition rates controlled by water retention time across inland waters

    NASA Astrophysics Data System (ADS)

    Catalán, Núria; Marcé, Rafael; Kothawala, Dolly N.; Tranvik, Lars. J.

    2016-07-01

    The loss of organic carbon during passage through the continuum of inland waters from soils to the sea is a critical component of the global carbon cycle. Yet, the amount of organic carbon mineralized and released to the atmosphere during its transport remains an open question, hampered by the absence of a common predictor of organic carbon decay rates. Here we analyse a compilation of existing field and laboratory measurements of organic carbon decay rates and water residence times across a wide range of aquatic ecosystems and climates. We find a negative relationship between the rate of organic carbon decay and water retention time across systems, entailing a decrease in organic carbon reactivity along the continuum of inland waters. We find that the half-life of organic carbon is short in inland waters (2.5 +/- 4.7 yr) compared to terrestrial soils and marine ecosystems, highlighting that freshwaters are hotspots of organic carbon degradation. Finally, we evaluate the response of organic carbon decay rates to projected changes in runoff. We calculate that regions projected to become drier or wetter as the global climate warms will experience changes in organic carbon decay rates of up to about 10%, which illustrates the influence of hydrological variability on the inland waters carbon cycle.

  5. Water vapor recovery from plant growth chambers

    NASA Technical Reports Server (NTRS)

    Ray, R. J.; Newbold, D. D.; Colton, R. H.; Mccray, S. B.

    1991-01-01

    NASA is investigating the use of plant growth chambers (PGCs) for space missions and for bases on the moon and Mars. Key to successful development of PGCs is a system to recover and reuse the water vapor that is transpired from the leaves of the plants. A design is presented for a simple, reliable, membrane-based system that allows the recovery, purification, and reuse of the transpired water vapor through control of temperature and humidity levels in PGCs. The system is based on two membrane technologies: (1) dehumidification membrane modules to remove water vapor from the air, and (2) membrane contactors to return water vapor to the PGC (and, in doing so, to control the humidity and temperature within the PGC). The membrane-based system promises to provide an ideal, stable growth environment for a variety of plants, through a design that minimizes energy usage, volume, and mass, while maximizing simplicity and reliability.

  6. Study type and plant litter identity modulating the response of litter decomposition to warming, elevated CO2, and elevated O3: A meta-analysis

    NASA Astrophysics Data System (ADS)

    Yue, Kai; Peng, Changhui; Yang, Wanqin; Peng, Yan; Fang, Junmin; Wu, Fuzhong

    2015-03-01

    Plant litter decomposition is one of the most important ecosystem carbon flux processes in terrestrial ecosystems and is usually regarded as sensitive to climate change. The goal of the present study was to examine the effects of changing climate variables on litter decomposition. By synthesizing data from multiple terrestrial ecosystems, we quantified the response of the litter decomposition rate to the independent effects of warming, elevated carbon dioxide (CO2), elevated ozone (O3), and the combined effects of elevated CO2 + elevated O3. Across all case studies, warming increased the litter decomposition rate significantly by 4.4%, but this effect could be reduced as a result of the negatively significant effects of elevated CO2 and elevated CO2 + elevated O3. The combined effects of elevated CO2 + elevated O3 decreased the litter decomposition rate significantly, and the magnitude appeared to be higher than that of the elevated CO2 per se. Moreover, the study type (field versus laboratory), ecosystem type, and plant litter identity and functional traits (growth form and litter form) were all important moderators regulating the response of litter decomposition to climate warming and elevated CO2 and O3. Although litter decomposition rate may show a moderate change as a result of the effects of multiple changing climate variables, the process of litter decomposition would be strongly altered due to the differing mechanisms of the effects of each climate change variable, suggesting that the global carbon cycle and biogeochemistry could be substantially affected.

  7. (Plant growth with limited water)

    SciTech Connect

    Not Available

    1992-01-01

    When water is in short supply, soybean stem growth is inhibited by a physical limitation followed in a few hours by metabolic changes that reduce the extensibility of the cell walls. The extensibility then becomes the main limitation. With time, there is a modest recovery in extensibility along with an accumulation of a 28kD protein in the walls of the growth-affected cells. A 3lkD protein that was 80% similar in amino acid sequence also was present but did not accumulate in the walls of the stem cells. In the stem, growth was inhibited and the mRNA for the 28kD protein increased in response to water deprivation but the mRNA for the 3 1 kD protein did not. The roots continued to grow and the mRNA for the 28kD protein did not accumulate but the mRNA for the 3lkD protein did. Thus, there was a tissuespecific response of gene expression that correlated with the contrasting growth response to low water potential in the same seedlings. Further work using immunogold labeling, fluorescence labeling, and western blotting gave evidence that the 28kD protein is located in the cell wall as well as several compartments in the cytoplasm. Preliminary experiments indicate that the 28kD protein is a phosphatase.

  8. Water treatment plants assessment at Talkha power plant.

    PubMed

    El-Sebaie, Olfat D; Abd El-Kerim, Ghazy E; Ramadan, Mohamed H; Abd El-Atey, Magda M; Taha, Sahr Ahmed

    2002-01-01

    Talkha power plant is the only power plant located in El-Mansoura. It generates electricity using two different methods by steam turbine and gas turbine. Both plants drew water from River Nile (208 m3 /h). The Nile raw water passes through different treatment processes to be suitable for drinking and operational uses. At Talkha power plant, there are two purification plants used for drinking water supply (100 m3/h) and for water demineralization supply (108 m3/h). This study aimed at studying the efficiency of the water purification plants. For drinking water purification plant, the annual River Nile water characterized by slightly alkaline pH (7.4-8), high annual mean values of turbidity (10.06 NTU), Standard Plate Count (SPC) (313.3 CFU/1 ml), total coliform (2717/100 ml), fecal coliform (0-2400/100 ml), and total algae (3 x 10(4) org/I). The dominant group of algae all over the study period was green algae. The blue green algae was abundant in Summer and Autumn seasons. The pH range, and the annual mean values of turbidity, TDS, total hardness, sulfates, chlorides, nitrates, nitrites, fluoride, and residual chlorine for purified water were in compliance with Egyptian drinking water standards. All the SPC recorded values with an annual mean value of 10.13 CFU/1 ml indicated that chlorine dose and contact time were not enough to kill the bacteria. However, they were in compliance with Egyptian decree (should not exceed 50 CFU/1 ml). Although the removal efficiency of the plant for total coliform and blue green algae was high (98.5% and 99.2%, respectively), the limits of the obtained results with an annual mean values of 40/100 ml and 15.6 org/l were not in compliance with the Egyptian decree (should be free from total coliform, fecal coliform and blue green algae). For water demineralization treatment plant, the raw water was characterized by slightly alkaline pH. The annual mean values of conductivity, turbidity, and TDS were 354.6 microS/cm, 10.84 NTU, and 214

  9. Analytical, toxicological and kinetic investigation of decomposition of the drug diclofenac in waters and wastes using gamma radiation.

    PubMed

    Bojanowska-Czajka, A; Kciuk, G; Gumiela, M; Borowiecka, S; Nałęcz-Jawecki, G; Koc, A; Garcia-Reyes, J F; Ozbay, D Solpan; Trojanowicz, M

    2015-12-01

    The radiolytic decomposition of the drug diclofenac (DCF), and in limited extent, also two other widely used drugs, ibuprofen and carbamazepine, was examined using liquid chromatography (LC) methods. The efficiency of DCF decomposition was examined in function of the absorbed dose of gamma radiation, and also in the presence of selected scavengers of radicals, which are commonly present in natural waters and wastes. Three different tests were employed for the monitoring of toxicity changes in the irradiated DCF solutions. The LC/mass spectrometry (MS) was used for the determination of products of DCF radiolysis. Using pulse-radiolysis method with the spectrophotometric detection, the rate constant values were determined for reactions of DCF with the main products of water radiolysis: hydroxyl radicals (1.24 ± 0.02) × 10(10) M(-1) s(-1) and hydrated electrons (3.1 ± 0.2) × 10(9) M(-1) s(-1). Their values indicate that both oxidative and reductive processes in radiolytic decomposition of DCF can take place in irradiated diluted aqueous solutions of DCF. The possibility of decomposition of all examined analytes was investigated in samples of river water and hospital waste. Compared to the previous studies, the conducted measurements in real samples were carried out at the concentration levels, which are close to those reported earlier in environmental samples. Graphical abstract ᅟ. PMID:26308920

  10. Effect of water vapor on the thermal decomposition process of zinc hydroxide chloride and crystal growth of zinc oxide

    SciTech Connect

    Kozawa, Takahiro; Onda, Ayumu; Yanagisawa, Kazumichi; Kishi, Akira; Masuda, Yasuaki

    2011-03-15

    Thermal decomposition process of zinc hydroxide chloride (ZHC), Zn{sub 5}(OH){sub 8}Cl{sub 2}.H{sub 2}O, prepared by a hydrothermal slow-cooling method has been investigated by simultaneous X-ray diffractometry and differential scanning calorimetry (XRD-DSC) and thermogravimetric-differential thermal analysis (TG-DTA) in a humidity-controlled atmosphere. ZHC was decomposed to ZnO through {beta}-Zn(OH)Cl as the intermediate phase, leaving amorphous hydrated ZnCl{sub 2}. In humid N{sub 2} with P{sub H{sub 2O}}=4.5 and 10 kPa, the hydrolysis of residual ZnCl{sub 2} was accelerated and the theoretical amount of ZnO was obtained at lower temperatures than in dry N{sub 2}, whereas significant weight loss was caused by vaporization of residual ZnCl{sub 2} in dry N{sub 2}. ZnO formed by calcinations in a stagnant air atmosphere had the same morphology of the original ZHC crystals and consisted of the c-axis oriented column-like particle arrays. On the other hand, preferred orientation of ZnO was inhibited in the case of calcinations in 100% water vapor. A detailed thermal decomposition process of ZHC and the effect of water vapor on the crystal growth of ZnO are discussed. -- Graphical abstract: Thermal decomposition process of zinc hydroxide chloride (ZHC), Zn{sub 5}(OH){sub 8}Cl{sub 2}.H{sub 2}O, has been investigated by novel thermal analyses with three different water vapor partial pressures. In the water vapor atmosphere, the formation of ZnO was completed at lower temperatures than in dry. Display Omitted highlights: > We examine the thermal decomposition of zinc hydroxide chloride in water vapor. > Water vapor had no effects on its thermal decomposition up to 230 {sup o}C. > Water vapor accelerated the decomposition of the residual ZnCl{sub 2} in ZnO. > Without water vapor, a large amount of ZnCl{sub 2} evaporated to form the c-axis oriented ZnO.

  11. 2. Water treatment plant entrance, view to W Fort ...

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

    2. Water treatment plant entrance, view to W - Fort Benton Water Treatment Plant, Filtration Plant, Lots 9-13 of Block 7, Fort Benton Original Townsite at Missouri River, Fort Benton, Chouteau County, MT

  12. 6. Water treatment plant, view NE, berm in foreground ...

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

    6. Water treatment plant, view NE, berm in foreground - Fort Benton Water Treatment Plant, Filtration Plant, Lots 9-13 of Block 7, Fort Benton Original Townsite at Missouri River, Fort Benton, Chouteau County, MT

  13. 5. Water treatment plant, view to N, berm in foreground ...

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

    5. Water treatment plant, view to N, berm in foreground - Fort Benton Water Treatment Plant, Filtration Plant, Lots 9-13 of Block 7, Fort Benton Original Townsite at Missouri River, Fort Benton, Chouteau County, MT

  14. 4. Water treatment plant, view to NW, berm in foreground ...

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

    4. Water treatment plant, view to NW, berm in foreground - Fort Benton Water Treatment Plant, Filtration Plant, Lots 9-13 of Block 7, Fort Benton Original Townsite at Missouri River, Fort Benton, Chouteau County, MT

  15. 3. Water treatment plant, view to W, detail of door ...

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

    3. Water treatment plant, view to W, detail of door area - Fort Benton Water Treatment Plant, Filtration Plant, Lots 9-13 of Block 7, Fort Benton Original Townsite at Missouri River, Fort Benton, Chouteau County, MT

  16. 13. Water treatment plant interior view of tanks in control ...

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

    13. Water treatment plant interior view of tanks in control room. View to SW - Fort Benton Water Treatment Plant, Filtration Plant, Lots 9-13 of Block 7, Fort Benton Original Townsite at Missouri River, Fort Benton, Chouteau County, MT

  17. 14. Water treatment plant interior view of chlorination room. View ...

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

    14. Water treatment plant interior view of chlorination room. View to N - Fort Benton Water Treatment Plant, Filtration Plant, Lots 9-13 of Block 7, Fort Benton Original Townsite at Missouri River, Fort Benton, Chouteau County, MT

  18. 8. Water treatment plant, view to SE, berm in foreground ...

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

    8. Water treatment plant, view to SE, berm in foreground covering settling tank - Fort Benton Water Treatment Plant, Filtration Plant, Lots 9-13 of Block 7, Fort Benton Original Townsite at Missouri River, Fort Benton, Chouteau County, MT

  19. 7. Water treatment plant, view to E, berm in foreground ...

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

    7. Water treatment plant, view to E, berm in foreground covering settling tank - Fort Benton Water Treatment Plant, Filtration Plant, Lots 9-13 of Block 7, Fort Benton Original Townsite at Missouri River, Fort Benton, Chouteau County, MT

  20. 10. Water treatment plant, view to S. 1965 addition is ...

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

    10. Water treatment plant, view to S. 1965 addition is in the foreground - Fort Benton Water Treatment Plant, Filtration Plant, Lots 9-13 of Block 7, Fort Benton Original Townsite at Missouri River, Fort Benton, Chouteau County, MT

  1. Beneath the Arctic Green: Have recent increases in plant production been offset by increases in soil decomposition?

    NASA Astrophysics Data System (ADS)

    Harden, J. W.; O'Donnell, J.; Fuller, C.; Sierra, C. A.; Johnson, K. D.; Manies, K.; Jorgenson, T.; Jones, M.; Ewing, S. A.; Yue, C.; Turetsky, M.

    2013-12-01

    Observational and modeling studies suggest that boreal vegetation has undergone an increase in plant production and C uptake in recent decades, coincident with increases in regional air temperatures, atmospheric CO2 concentration, and fire/successional dynamics. In the North American boreal forest, wildfires have increased in extent, season length, and depth of burn, driving higher C emission from black spruce ecosystems. Meanwhile, responses in soil systems that dictate the net ecosystem carbon (C) balance are less well known, in part owing to problems with elucidating the relatively small signals of organic matter decomposition from the large C fluxes of gross primary production and ecosystem respiration. Here, we measured net C accumulation in soils from Interior Alaska using radiocarbon (14C), lead isotopes (210Pb), cesium isotopes (137Cs), and time sequences of forest regeneration (fire and thaw chronosequences). We use soil 14C and non-steady-state models to estimate turnover times for soil organic C. Over the past century, rates of soil C uptake based on upland chronosequences ranged from -20 to -30 g C/m2/yr, but regionally likely shifted toward a reduced sink or source of - 20 to + 10 g C/m2/yr in recent decades due to increased combustion losses and deep C mobilization associated with permafrost thaw. C accumulation rates in lowland thermokarst chronosequences suggest a mixed sink/source effect, with post-thaw increases in surface accumulation potentially offset by decomposition at depth, or enhanced initial decomposition of C from previously frozen soils, followed by long-term net uptake of post-thaw peat. Large uncertainties remain regarding the turnover of soil organic C in boreal soil, yet enhanced decomposition has likely offset the increase in NPP, resulting in a reduced sink activity relative to pre1960s.

  2. Capacitive Soil Moisture Sensor for Plant Watering

    NASA Astrophysics Data System (ADS)

    Maier, Thomas; Kamm, Lukas

    2016-04-01

    How can you realize a water saving and demand-driven plant watering device? To achieve this you need a sensor, which precisely detects the soil moisture. Designing such a sensor is the topic of this poster. We approached this subject with comparing several physical properties of water, e.g. the conductivity, permittivity, heat capacity and the soil water potential, which are suitable to detect the soil moisture via an electronic device. For our project we have developed a sensor device, which measures the soil moisture and provides the measured values for a plant watering system via a wireless bluetooth 4.0 network. Different sensor setups have been analyzed and the final sensor is the result of many iterative steps of improvement. In the end we tested the precision of our sensor and compared the results with theoretical values. The sensor is currently being used in the Botanical Garden of the Friedrich-Alexander-University in a long-term test. This will show how good the usability in the real field is. On the basis of these findings a marketable sensor will soon be available. Furthermore a more specific type of this sensor has been designed for the EU:CROPIS Space Project, where tomato plants will grow at different gravitational forces. Due to a very small (15mm x 85mm x 1.5mm) and light (5 gramm) realisation, our sensor has been selected for the space program. Now the scientists can monitor the water content of the substrate of the tomato plants in outer space and water the plants on demand.

  3. Layerwise decomposition of water dynamics in reverse micelles: A simulation study of two-dimensional infrared spectrum

    NASA Astrophysics Data System (ADS)

    Biswas, Rajib; Furtado, Jonathan; Bagchi, Biman

    2013-10-01

    We present computer simulation study of two-dimensional infrared spectroscopy (2D-IR) of water confined in reverse micelles (RMs) of various sizes. The present study is motivated by the need to understand the altered dynamics of confined water by performing layerwise decomposition of water, with an aim to quantify the relative contributions of different layers water molecules to the calculated 2D-IR spectrum. The 0-1 transition spectra clearly show substantial elongation, due to inhomogeneous broadening and incomplete spectral diffusion, along the diagonal in the surface water layer of different sized RMs. Fitting of the frequency fluctuation correlation functions reveal that the motion of the surface water molecules is sub-diffusive and indicate the constrained nature of their dynamics. This is further supported by two peak nature of the angular analogue of van Hove correlation function. With increasing system size, the water molecules become more diffusive in nature and spectral diffusion almost completes in the central layer of the larger size RMs. Comparisons between experiments and simulations establish the correspondence between the spectral decomposition available in experiments with the spatial decomposition available in simulations. Simulations also allow a quantitative exploration of the relative role of water, sodium ions, and sulfonate head groups in vibrational dephasing. Interestingly, the negative cross correlation between force on oxygen and hydrogen of O-H bond in bulk water significantly decreases in the surface layer of each RM. This negative cross correlation gradually increases in the central water pool with increasing RMs size and this is found to be partly responsible for the faster relaxation rate of water in the central pool.

  4. Experimental burial inhibits methanogenesis and anaerobic decomposition in water-saturated peats.

    PubMed

    Blodau, Christian; Siems, Melanie; Beer, Julia

    2011-12-01

    A mechanistic understanding of carbon (C) sequestration and methane (CH(4)) production is of great interest due to the importance of these processes for the global C budget. Here we demonstrate experimentally, by means of column experiments, that burial of water saturated, anoxic bog peat leads to inactivation of anaerobic respiration and methanogenesis. This effect can be related to the slowness of diffusive transport of solutes and evolving energetic constraints on anaerobic respiration. Burial lowered decomposition constants in homogenized peat sand mixtures from about 10(-5) to 10(-7) yr(-1), which is considerably slower than previously assumed, and methanogenesis slowed down in a similar manner. The latter effect could be related to acetoclastic methanogenesis approaching a minimum energy quantum of -25 kJ mol(-1) (CH(4)). Given the robustness of hydraulic properties that locate the oxic-anoxic boundary near the peatland surface and constrain solute transport deeper into the peat, this effect has likely been critical for building the peatland C store and will continue supporting long-term C sequestration in northern peatlands even under moderately changing climatic conditions. PMID:21958021

  5. Low-order modelling of shallow water equations for sensitivity analysis using proper orthogonal decomposition

    NASA Astrophysics Data System (ADS)

    Zokagoa, Jean-Marie; Soulaïmani, Azzeddine

    2012-06-01

    This article presents a reduced-order model (ROM) of the shallow water equations (SWEs) for use in sensitivity analyses and Monte-Carlo type applications. Since, in the real world, some of the physical parameters and initial conditions embedded in free-surface flow problems are difficult to calibrate accurately in practice, the results from numerical hydraulic models are almost always corrupted with uncertainties. The main objective of this work is to derive a ROM that ensures appreciable accuracy and a considerable acceleration in the calculations so that it can be used as a surrogate model for stochastic and sensitivity analyses in real free-surface flow problems. The ROM is derived using the proper orthogonal decomposition (POD) method coupled with Galerkin projections of the SWEs, which are discretised through a finite-volume method. The main difficulty of deriving an efficient ROM is the treatment of the nonlinearities involved in SWEs. Suitable approximations that provide rapid online computations of the nonlinear terms are proposed. The proposed ROM is applied to the simulation of hypothetical flood flows in the Bordeaux breakwater, a portion of the 'Rivière des Prairies' located near Laval (a suburb of Montreal, Quebec). A series of sensitivity analyses are performed by varying the Manning roughness coefficient and the inflow discharge. The results are satisfactorily compared to those obtained by the full-order finite volume model.

  6. Streambank plants vital to water quality

    SciTech Connect

    Sherman, H.

    1989-08-01

    Studies of plants suitable for stabilizing streambanks are described. Sediments caused by soil erosion in Northern California's mountain meadows clog drinking water reservoirs, reduce fish populations, and block hydroelectric dams. Studies of the effect of seasonal climate change on root growth, photosynthesis, and water use of willows and grasses using a below-ground periscope and portable photosynthesis are described. In addition, studies to evaluate the seasonal effect of livestock grazing are in progress.

  7. Experiences in optimizing water treatment plant performance

    SciTech Connect

    Hess, A.F.; Huntley, G.

    1996-11-01

    The South Central Connecticut Regional Water Authority (RWA) provides an average of 55 million gallons per day (mgd) to approximately 380,000 people in 12 municipalities in the Greater New Haven area of Connecticut. About 80 percent of the water is supplied from three surface water treatment plants and the other 20 percent comes from five wellfields. The surface water supply system includes 9 reservoirs with a total capacity of about 16 billion gallons. The Authority owns and controls approximately 40% of the 67 square miles of the watershed for these reservoirs. The source water quality is consistent and generally very good. A summary of average water for selected parameters which impact the treatability of the supplies is presented in Table 1.

  8. CHEMICAL DOSER FOR AGUACLARA WATER TREATMENT PLANTS

    EPA Science Inventory

    The design procedure for the nonlinear chemical doser will be validated and extended over a wide range of flow rates. The doser will be tested in several full-scale municipal water treatment plants. We will also generate improved design algorithms for rapid mix, flocculation,...

  9. WATER REUSE IN A PAPER REPROCESSING PLANT

    EPA Science Inventory

    This project was undertaken to determine the feasibility of water reuse in a paper reprocessing plant with the goal being to 'close the loop' or to demonstrate zero discharge technology. Before the project began, Big Chief Roofing Company at Ardmore, OK, was discharging 7.89 1/se...

  10. RECYCLING OF WATER IN POULTRY PROCESSING PLANTS

    EPA Science Inventory

    Studies were conducted on recycling chiller water in a poultry processing plant. The recycling system must be provided with the capability of removing solids and controlling the microbial population. UV was used to control the microbial population. For this control to be effectiv...

  11. DECOMPOSITION OF TRIHALOACETIC ACIDS AND FORMATION OF THE CORRESPONDING TRIHALOMETHANES IN DRINKING WATER. (R826834)

    EPA Science Inventory

    The decomposition of trihaloacetic acids [bromodichloroacetic acid (BDCAA), dibromochloroacetic acid (DBCAA), tribromoacetic acid (TBAA)], and the formation of the corresponding trihalomethanes [bromodichloromethane (BDCM), dibromochloromethane (DBCM), tribromomethane (TBM)] w...

  12. Influence of sodium carbonate on decomposition of formic acid by pulsed discharge plasma inside bubble in water

    NASA Astrophysics Data System (ADS)

    Iwabuchi, Masashi; Takahashi, Katsuyuki; Takaki, Koichi; Satta, Naoya

    2016-07-01

    The influence of sodium carbonate on the decomposition of formic acid by discharge inside bubbles in water was investigated experimentally. Oxygen or argon gases were injected into the water through a vertically positioned glass tube, in which the high-voltage wire electrode was placed to generate plasmas at low applied voltage. The concentration of formic acid was determined by ion chromatography. In the case of sodium carbonate additive, the pH increased owing to the decomposition of the formic acid. In the case of oxygen injection, the percentage of conversion of formic acid increased with increasing pH because the reaction rate of ozone with formic acid increased with increasing pH. In the case of argon injection, the percentage of conversion was not affected by the pH owing to the high rate loss of hydroxyl radicals.

  13. A new conceptual model on the fate and controls of fresh and pyrolized plant litter decomposition

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The leaching of dissolved organic matter (DOM) from fresh and pyrolyzed aboveground plant inputs to the soil is a major pathway by which decomposing aboveground plant material contributes to soil organic matter formation. Understanding how aboveground plant input chemical traits control the partiti...

  14. Moisture drives surface decomposition in thawing tundra

    NASA Astrophysics Data System (ADS)

    Hicks Pries, Caitlin E.; Schuur, E. A. G.; Vogel, Jason G.; Natali, Susan M.

    2013-07-01

    Permafrost thaw can affect decomposition rates by changing environmental conditions and litter quality. As permafrost thaws, soils warm and thermokarst (ground subsidence) features form, causing some areas to become wetter while other areas become drier. We used a common substrate to measure how permafrost thaw affects decomposition rates in the surface soil in a natural permafrost thaw gradient and a warming experiment in Healy, Alaska. Permafrost thaw also changes plant community composition. We decomposed 12 plant litters in a common garden to test how changing plant litter inputs would affect decomposition. We combined species' tissue-specific decomposition rates with species and tissue-level estimates of aboveground net primary productivity to calculate community-weighted decomposition constants at both the thaw gradient and warming experiment. Moisture, specifically growing season precipitation and water table depth, was the most significant driver of decomposition. At the gradient, an increase in growing season precipitation from 200 to 300 mm increased mass loss of the common substrate by 100%. At the warming experiment, a decrease in the depth to the water table from 30 to 15 cm increased mass loss by 100%. At the gradient, community-weighted decomposition was 21% faster in extensive than in minimal thaw, but was similar when moss production was included. Overall, the effect of climate change and permafrost thaw on surface soil decomposition are driven more by precipitation and soil environment than by changes to plant communities. Increasing soil moisture is thereby another mechanism by which permafrost thaw can become a positive feedback to climate change.

  15. VIEW OF BUILDING 124, THE WATER TREATMENT PLANT, LOOKING NORTHEAST. ...

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

    VIEW OF BUILDING 124, THE WATER TREATMENT PLANT, LOOKING NORTHEAST. THE ROCKY FLATS PLANT WATER SUPPLY, TREATMENT, STORAGE, AND DISTRIBUTION SYSTEM HAS OPERATED CONTINUOUSLY SINCE 1953 - Rocky Flats Plant, Water Treatment Plant, West of Third Street, north of Cedar Avenue, Golden, Jefferson County, CO

  16. Chemical manipulation of plant water use.

    PubMed

    Helander, Jonathan D M; Vaidya, Aditya S; Cutler, Sean R

    2016-02-01

    Agricultural productivity is dictated by water availability and consequently drought is the major source of crop losses worldwide. The phytohormone abscisic acid (ABA) is elevated in response to water deficit and modulates drought tolerance by reducing water consumption and inducing other drought-protective responses. The recent identification of ABA receptors, elucidation of their structures and understanding of the core ABA signaling network has created new opportunities for agrochemical development. An unusually large gene family encodes ABA receptors and, until recently, it was unclear if selective or pan-agonists would be necessary for modulating water use. The recent identification of the selective agonist quinabactin has resolved this issue and defined Pyrabactin Resistance 1 (PYR1) and its close relatives as key targets for water use control. This review provides an overview of the structure and function of ABA receptors, progress in the development of synthetic agonists, and the use of orthogonal receptors to enable agrochemical control in transgenic plants. PMID:26612713

  17. The interaction between decomposition, net N and P mineralization and their mobilization to the surface water in fens.

    PubMed

    Geurts, Jeroen J M; Smolders, Alfons J P; Banach, Artur M; van de Graaf, Jan P M; Roelofs, Jan G M; Lamers, Leon P M

    2010-06-01

    Worldwide, fens and peat lakes that used to be peat-forming systems have become a significant source of C, N and P due to increased peat decomposition. To test the hypothesis that net nutrient mineralization rates may be uncoupled from decomposition rates, we investigated decomposition and net mineralization rates of nutrients in relation to sediment and pore water characteristics. We incubated 28 non-calcareous peat sediments and floating fen soils under aerobic and anaerobic conditions. We also tried to find a simple indicator to estimate the potential nutrient mobilization rates from peat sediments to the water layer by studying their relation with sediment and pore water characteristics in 44 Dutch non-calcareous peat lakes and ditches. Decomposition rates were primarily determined by the organic matter content, and were higher under aerobic conditions. However, highly decomposed peat sediments with low C:P and C:N ratios still showed high net nutrient mineralization rates. At Fe:PO(4) ratios below 1molmol(-1), PO(4) mobilization from the sediment to the water layer was considerable and linearly related to the pore water PO(4) concentration. At higher ratios, there was a strong linear correlation between the Fe:PO(4) ratio and PO(4) mobilization. Hence, measuring Fe and PO(4) in anaerobic sediment pore water provides a powerful tool for a quick assessment of internal PO(4) fluxes. Mobilization of mineral N was largely determined by diffusion. Total sediment Fe:S ratios gave an important indication of the amount of Fe that is available to immobilize PO(4). Pore water Fe concentrations decreased at ratios <1molmol(-1), whereas pore water PO(4) concentrations and PO(4) mobilization to the water layer increased. As PO(4) mobilization rates from the sediment to the water layer contribute to almost half of the total P load in Dutch peat lakes and fens, it is of pivotal importance to examine the magnitude of internal fluxes. Dredging of the nutrient-rich upper

  18. Plant herbivory responses through changes in leaf quality have no effect on subsequent leaf-litter decomposition in a neotropical rain forest tree community.

    PubMed

    Cárdenas, Rafael E; Hättenschwiler, Stephan; Valencia, Renato; Argoti, Adriana; Dangles, Olivier

    2015-08-01

    It is commonly accepted that plant responses to foliar herbivory (e.g. plant defenses) can influence subsequent leaf-litter decomposability in soil. While several studies have assessed the herbivory-decomposability relationship among different plant species, experimental tests at the intra-specific level are rare, although critical for a mechanistic understanding of how herbivores affect decomposition and its consequences at the ecosystem scale. Using 17 tree species from the Yasuní National Park, Ecuadorian Amazonia, and applying three different herbivore damage treatments, we experimentally tested whether the plant intra-specific responses to herbivory, through changes in leaf quality, affect subsequent leaf-litter decomposition in soil. We found no effects of herbivore damage on the subsequent decomposition of leaf litter within any of the species tested. Our results suggest that leaf traits affecting herbivory are different from those influencing decomposition. Herbivore damage showed much higher intra-specific than inter-specific variability, while we observed the opposite for decomposition. Our findings support the idea that interactions between consumers and their resources are controlled by different factors for the green and the brown food-webs in tropical forests, where herbivory may not necessarily generate any direct positive or negative feedbacks for nutrient cycling. PMID:25771942

  19. Decomposition of atrazine traces in water by combination of non-thermal electrical discharge and adsorption on nanofiber membrane.

    PubMed

    Vanraes, Patrick; Willems, Gert; Daels, Nele; Van Hulle, Stijn W H; De Clerck, Karen; Surmont, Pieter; Lynen, Frederic; Vandamme, Jeroen; Van Durme, Jim; Nikiforov, Anton; Leys, Christophe

    2015-04-01

    In recent decades, several types of persistent substances are detected in the aquatic environment at very low concentrations. Unfortunately, conventional water treatment processes are not able to remove these micropollutants. As such, advanced treatment methods are required to meet both current and anticipated maximally allowed concentrations. Plasma discharge in contact with water is a promising new technology, since it produces a wide spectrum of oxidizing species. In this study, a new type of reactor is tested, in which decomposition by atmospheric pulsed direct barrier discharge (pDBD) plasma is combined with micropollutant adsorption on a nanofiber polyamide membrane. Atrazine is chosen as model micropollutant with an initial concentration of 30 μg/L. While the H2O2 and O3 production in the reactor is not influenced by the presence of the membrane, there is a significant increase in atrazine decomposition when the membrane is added. With membrane, 85% atrazine removal can be obtained in comparison to only 61% removal without membrane, at the same experimental parameters. The by-products of atrazine decomposition identified by HPLC-MS are deethylatrazine and ammelide. Formation of these by-products is more pronounced when the membrane is added. These results indicate the synergetic effect of plasma discharge and pollutant adsorption, which is attractive for future applications of water treatment. PMID:25482844

  20. Atomic decomposition of the protein solvation free energy and its application to amyloid-beta protein in water

    NASA Astrophysics Data System (ADS)

    Chong, Song-Ho; Ham, Sihyun

    2011-07-01

    We report the development of an atomic decomposition method of the protein solvation free energy in water, which ascribes global change in the solvation free energy to local changes in protein conformation as well as in hydration structure. So far, empirical decomposition analyses based on simple continuum solvation models have prevailed in the study of protein-protein interactions, protein-ligand interactions, as well as in developing scoring functions for computer-aided drug design. However, the use of continuum solvation model suffers serious drawbacks since it yields the protein free energy landscape which is quite different from that of the explicit solvent model and since it does not properly account for the non-polar hydrophobic effects which play a crucial role in biological processes in water. Herein, we develop an exact and general decomposition method of the solvation free energy that overcomes these hindrances. We then apply this method to elucidate the molecular origin for the solvation free energy change upon the conformational transitions of 42-residue amyloid-beta protein (Aβ42) in water, whose aggregation has been implicated as a primary cause of Alzheimer's disease. We address why Aβ42 protein exhibits a great propensity to aggregate when transferred from organic phase to aqueous phase.

  1. The impact of the invasive shrub Lonicera maackii on the decomposition dynamics of a native plant community.

    PubMed

    Poulette, Megan M; Arthur, Mary A

    2012-03-01

    Invasive plants may have variable effects within a given environment depending on their interactions with the dominant native species, yet little research has examined such species-species interactions within a site. Savanna trees with nonoverlapping canopies offer an ideal opportunity to assess associated changes in the ecosystem processes that result from interactions between an invasive species and different native tree species. We examined the influence of the exotic invasive shrub Lonicera maackii on decomposition dynamics under three native tree species: Fraxinus quadrangulata, Quercus muehlenbergii, and Carya ovata. Litter decomposition rates and litter C and N were evaluated over two years using single- and mixed-species litterbags (L. maackii and individual tree species litter); microarthropod abundance was measured at 6 weeks using Tulgren funnels. Litter from the invasive L. maackii decomposed and lost N more rapidly than the litter of the three native tree species. The rate at which L. maackii decomposed depended on its location, with L. maackii litter decomposing and losing N more rapidly under C. ovata than under the other two native tree species. Mixing L. maackii with the native species' litter did not accelerate litter mass loss overall but did result in synergistic N losses at variable times throughout the experiment, further highlighting the variable interaction between native species and L. maackii. Nitrogen loss was significantly higher than expected in mixtures of C. ovata + L. maackii litter at 6 weeks, in F. quadrangulata + L. maackii litter at 12 weeks, and in Q. muehlenbergii + L. maackii litter at 24 weeks. If the effects of invasive species on certain ecosystem processes, such as litter decomposition, are strongly influenced by their association with native species, this could suggest the need for a more nuanced understanding of the vulnerability of ecosystem processes to invasions of L. maackii and potentially other invasive species

  2. A Class-Information-Based Penalized Matrix Decomposition for Identifying Plants Core Genes Responding to Abiotic Stresses

    PubMed Central

    Liu, Jin-Xing; Liu, Jian; Gao, Ying-Lian; Mi, Jian-Xun; Ma, Chun-Xia; Wang, Dong

    2014-01-01

    In terms of making genes expression data more interpretable and comprehensible, there exists a significant superiority on sparse methods. Many sparse methods, such as penalized matrix decomposition (PMD) and sparse principal component analysis (SPCA), have been applied to extract plants core genes. Supervised algorithms, especially the support vector machine-recursive feature elimination (SVM-RFE) method, always have good performance in gene selection. In this paper, we draw into class information via the total scatter matrix and put forward a class-information-based penalized matrix decomposition (CIPMD) method to improve the gene identification performance of PMD-based method. Firstly, the total scatter matrix is obtained based on different samples of the gene expression data. Secondly, a new data matrix is constructed by decomposing the total scatter matrix. Thirdly, the new data matrix is decomposed by PMD to obtain the sparse eigensamples. Finally, the core genes are identified according to the nonzero entries in eigensamples. The results on simulation data show that CIPMD method can reach higher identification accuracies than the conventional gene identification methods. Moreover, the results on real gene expression data demonstrate that CIPMD method can identify more core genes closely related to the abiotic stresses than the other methods. PMID:25180509

  3. Mass transfer in fuel cells. [electron microscopy of components, thermal decomposition of Teflon, water transport, and surface tension of KOH solutions

    NASA Technical Reports Server (NTRS)

    Walker, R. D., Jr.

    1973-01-01

    Results of experiments on electron microscopy of fuel cell components, thermal decomposition of Teflon by thermogravimetry, surface area and pore size distribution measurements, water transport in fuel cells, and surface tension of KOH solutions are described.

  4. Pt/TiO2 (Rutile) Catalysts for Sulfuric Acid Decomposition in Sulfur-Based Thermochemical Water-Splitting Cycles

    SciTech Connect

    L. M. Petkovic; D. M. Ginosar; H. W. Rollins; K. C. Burch; P. J. Pinhero; H. H. Farrell

    2008-04-01

    Thermochemical cycles consist of a series of chemical reactions to produce hydrogen from water at lower temperatures than by direct thermal decomposition. All the sulfur-based cycles for water splitting employ the sulfuric acid decomposition reaction. This work reports the studies performed on platinum supported on titania (rutile) catalysts to investigate the causes of catalyst deactivation under sulfuric acid decomposition reaction conditions. Samples of 1 wt% Pt/TiO2 (rutile) catalysts were submitted to flowing concentrated sulfuric acid at 1123 K and atmospheric pressure for different times on stream (TOS) between 0 and 548 h. Post-operation analyses of the spent catalyst samples showed that Pt oxidation and sintering occurred under reaction conditions and some Pt was lost by volatilization. Pt loss rate was higher at initial times but total loss appeared to be independent of the gaseous environment. Catalyst activity showed an initial decrease that lasted for about 66 h, followed by a slight recovery of activity between 66 and 102 h TOS, and a period of slower deactivation after 102 h TOS. Catalyst sulfation did not seem to be detrimental to catalyst activity and the activity profile suggested that a complex dynamical situation involving platinum sintering, volatilization, and oxidation, along with TiO2 morphological changes affected catalyst activity in a non-monotonic way.

  5. Prediction of the Maximum Temperature for Life Based on the Stability of Metabolites to Decomposition in Water

    PubMed Central

    Bains, William; Xiao, Yao; Yu, Changyong

    2015-01-01

    The components of life must survive in a cell long enough to perform their function in that cell. Because the rate of attack by water increases with temperature, we can, in principle, predict a maximum temperature above which an active terrestrial metabolism cannot function by analysis of the decomposition rates of the components of life, and comparison of those rates with the metabolites’ minimum metabolic half-lives. The present study is a first step in this direction, providing an analytical framework and method, and analyzing the stability of 63 small molecule metabolites based on literature data. Assuming that attack by water follows a first order rate equation, we extracted decomposition rate constants from literature data and estimated their statistical reliability. The resulting rate equations were then used to give a measure of confidence in the half-life of the metabolite concerned at different temperatures. There is little reliable data on metabolite decomposition or hydrolysis rates in the literature, the data is mostly confined to a small number of classes of chemicals, and the data available are sometimes mutually contradictory because of varying reaction conditions. However, a preliminary analysis suggests that terrestrial biochemistry is limited to environments below ~150–180 °C. We comment briefly on why pressure is likely to have a small effect on this. PMID:25821932

  6. Plant water relations II: how plants manage water deficit and why it matters

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The availability of fresh water is possibly the greatest limitation to our ability to feed the growing human population (9 billion people forecast by 2050 and 11 billion by 2100). This Teaching Tool examines why water is so critical for plant growth and particularly their food production (primarily ...

  7. Decomposition analysis of water footprint changes in a water-limited river basin: a case study of the Haihe River basin, China

    NASA Astrophysics Data System (ADS)

    Zhi, Y.; Yang, Z. F.; Yin, X. A.

    2014-05-01

    Decomposition analysis of water footprint (WF) changes, or assessing the changes in WF and identifying the contributions of factors leading to the changes, is important to water resource management. Instead of focusing on WF from the perspective of administrative regions, we built a framework in which the input-output (IO) model, the structural decomposition analysis (SDA) model and the generating regional IO tables (GRIT) method are combined to implement decomposition analysis for WF in a river basin. This framework is illustrated in the WF in Haihe River basin (HRB) from 2002 to 2007, which is a typical water-limited river basin. It shows that the total WF in the HRB increased from 4.3 × 1010 m3 in 2002 to 5.6 × 1010 m3 in 2007, and the agriculture sector makes the dominant contribution to the increase. Both the WF of domestic products (internal) and the WF of imported products (external) increased, and the proportion of external WF rose from 29.1 to 34.4%. The technological effect was the dominant contributor to offsetting the increase of WF. However, the growth of WF caused by the economic structural effect and the scale effect was greater, so the total WF increased. This study provides insights about water challenges in the HRB and proposes possible strategies for the future, and serves as a reference for WF management and policy-making in other water-limited river basins.

  8. Gasification characteristics of an activated carbon catalyst during the decomposition of hazardous waste material in supercritical water

    SciTech Connect

    Matsumura, Yukihiko; Nuessle, F.W.; Antal, M.J. Jr.

    1996-12-31

    Recently, carbonaceous materials including activated carbon were proven to be effective catalysts for hazardous waste gasification in supercritical water. Using coconut shell activated carbon catalyst, complete decomposition of industrial organic wastes including methanol and acetic acid was achieved. During this process, the total mass of the activated carbon catalyst changes by two competing processes: a decrease in weight via gasification of the carbon by supercritical water, or an increase in weight by deposition of carbonaceous materials generated by incomplete gasification of the biomass feedstocks. The deposition of carbonaceous materials does not occur when complete gasification is realized. Gasification of the activated carbon in supercritical water is often favored, resulting in changes in the quality and quantity of the catalyst. To thoroughly understand the hazardous waste decomposition process, a more complete understanding of the behavior of activated carbon in pure supercritical water is needed. The gasification rate of carbon by water vapor at subcritical pressures was studied in relation to coal gasification and generating activated carbon.

  9. [Effects of brackish water irrigation on soil enzyme activity, soil CO2 flux and organic matter decomposition].

    PubMed

    Zhang, Qian-qian; Wang, Fei; Liu, Tao; Chu, Gui-xin

    2015-09-01

    Brackish water irrigation utilization is an important way to alleviate water resource shortage in arid region. A field-plot experiment was set up to study the impact of the salinity level (0.31, 3.0 or 5.0 g · L(-1) NaCl) of irrigated water on activities of soil catalase, invertase, β-glucosidase, cellulase and polyphenoloxidase in drip irrigation condition, and the responses of soil CO2 flux and organic matter decomposition were also determined by soil carbon dioxide flux instrument (LI-8100) and nylon net bag method. The results showed that in contrast with fresh water irrigation treatment (CK), the activities of invertase, β-glucosidase and cellulase in the brackish water (3.0 g · L(-1)) irrigation treatment declined by 31.7%-32.4%, 29.7%-31.6%, 20.8%-24.3%, respectively, while soil polyphenoloxidase activity was obviously enhanced with increasing the salinity level of irrigated water. Compared to CK, polyphenoloxidase activity increased by 2.4% and 20.5%, respectively, in the brackish water and saline water irrigation treatments. Both soil microbial biomass carbon and microbial quotient decreased with increasing the salinity level, whereas, microbial metabolic quotient showed an increasing tendency with increasing the salinity level. Soil CO2 fluxes in the different treatments were in the order of CK (0.31 g · L(-1)) > brackish water irrigation (3.0 g · L(-1)) ≥ saline water irrigation (5.0 g · L(-1)). Moreover, CO2 flux from plastic film mulched soil was always much higher than that from no plastic film mulched soil, regardless the salinity of irrigated water. Compared with CK, soil CO2 fluxes in the saline water and brackish water treatments decreased by 29.8% and 28.2% respectively in the boll opening period. The decomposition of either cotton straw or alfalfa straw in the different treatments was in the sequence of CK (0.31 g · L(-1)) > brackish water irrigation (3.0 g · L(-1)) > saline water treatment (5.0 g · L(-1)). The organic matter

  10. Unveiling the Mechanisms Leading to H2 Production Promoted by Water Decomposition on Epitaxial Graphene at Room Temperature.

    PubMed

    Politano, Antonio; Cattelan, Mattia; Boukhvalov, Danil W; Campi, Davide; Cupolillo, Anna; Agnoli, Stefano; Apostol, Nicoleta G; Lacovig, Paolo; Lizzit, Silvano; Farías, Daniel; Chiarello, Gennaro; Granozzi, Gaetano; Larciprete, Rosanna

    2016-04-26

    By means of a combination of surface-science spectroscopies and theory, we investigate the mechanisms ruling the catalytic role of epitaxial graphene (Gr) grown on transition-metal substrates for the production of hydrogen from water. Water decomposition at the Gr/metal interface at room temperature provides a hydrogenated Gr sheet, which is buckled and decoupled from the metal substrate. We evaluate the performance of Gr/metal interface as a hydrogen storage medium, with a storage density in the Gr sheet comparable with state-of-the-art materials (1.42 wt %). Moreover, thermal programmed reaction experiments show that molecular hydrogen can be released upon heating the water-exposed Gr/metal interface above 400 K. The Gr hydro/dehydrogenation process might be exploited for an effective and eco-friendly device to produce (and store) hydrogen from water, i.e., starting from an almost unlimited source. PMID:27054462

  11. Gasification characteristics of an activated carbon catalyst during the decomposition of hazardous waste materials in supercritical water

    SciTech Connect

    Matsumura, Yukihiko; Nuessle, F.W.; Antal, M.J. Jr.

    1996-10-01

    Recently, carbonaceous materials were proved to be effective catalysts for hazardous waste decomposition in supercritical water. Gasification of the carbonaceous catalyst itself is also expected, however, under supercritical conditions. Thus, it is essential to determine the gasification rate of the carbonaceous materials during this process to determine the active lifetime of the catalysts. For this purpose, the gasification characteristics of granular coconut shell activated carbon in supercritical water alone (600-650{degrees}C, 25.5-34.5 MPa) were investigated. The gasification rate at subatmospheric pressure agreed well with the gasification rate at supercritical conditions, indicating the same reaction mechanism. Methane generation under these conditions is via pyrolysis, and thus is not affected by the water pressure. An iodine number increase of 25% was observed as a result of the supercritical water gasification.

  12. Performance of small water treatment plants: The case study of Mutshedzi Water Treatment Plant

    NASA Astrophysics Data System (ADS)

    Makungo, R.; Odiyo, J. O.; Tshidzumba, N.

    The performance of small water treatment plants (SWTPs) was evaluated using Mutshedzi WTP as a case study. The majority of SWTPs in South Africa (SA) that supply water to rural villages face problems of cost recovery, water wastages, limited size and semi-skilled labour. The raw and final water quality analyses and their compliance were used to assess the performance of the Mutshedzi WTP. Electrical conductivity (EC), pН and turbidity were measured in the field using a portable multimeter and a turbidity meter respectively. Atomic Absorption Spectrometry and Ion Chromatography were used to analyse metals and non-metals respectively. The results were compared with the Department of Water Affairs (DWA) guidelines for domestic use. The turbidity levels partially exceeded the recommended guidelines for domestic water use of 1 NTU. The concentrations of chemical parameters in final water were within the DWA guidelines for domestic water use except for fluoride, which exceeded the maximum allowable guideline of 1.5 mg/L in August 2009. Mutshedzi WTP had computed compliance for raw and final water analyses ranging from 79% to 93% and 86% to 93% throughout the sampling period, respectively. The results from earlier studies showed that the microbiological quality of final water in Mutshedzi WTP complied with the recommended guidelines, eliminating the slight chance of adverse aesthetic effects and infectious disease transmission associated with the turbidity values between 1 and 5 NTU. The study concluded that Mutshedzi WTP, though moving towards compliance, is still not producing adequate quality of water. Other studies also indicated that the quantity of water produced from Mutshedzi WTP was inadequate. The findings of the study indicate that lack of monitoring of quantity of water supplied to each village, dosage of treatment chemicals, the treatment capacity of the WTP and monitoring the quality of water treated are some of the factors that limit the performance of

  13. Mechanism and Mitigation of the Decomposition of an Oxorhenium Complex-Based Heterogeneous Catalyst for Perchlorate Reduction in Water.

    PubMed

    Liu, Jinyong; Chen, Xi; Wang, Yin; Strathmann, Timothy J; Werth, Charles J

    2015-11-01

    A biomimetic heterogeneous catalyst combining palladium nanoparticles and an organic ligand-coordinated oxorhenium complex on activated carbon, Re(hoz)2-Pd/C, was previously developed and shown to reduce aqueous perchlorate (ClO4-) with H2 at a rate ∼100 times faster than the first generation ReOx-Pd/C catalyst prepared from perrhenate (ReO4-). However, the immobilized Re(hoz)2 complex was shown to partially decompose and leach into water as ReO4-, leading to an irreversible loss of catalytic activity. In this work, the stability of the immobilized Re(hoz)2 complex is shown to depend on kinetic competition between three processes: (1) ReV(hoz)2 oxidation by ClO4- and its reduction intermediates ClOx-, (2) ReVII(hoz)2 reduction by Pd-activated hydrogen, and (3) hydrolytic ReVII(hoz)2 decomposition. When ReV(hoz)2 oxidation is faster than ReVII(hoz)2 reduction, the ReVII(hoz)2 concentration builds up and leads to hydrolytic decomposition to ReO4- and free hoz ligand. Rapid ReV(hoz)2 oxidation is mainly promoted by highly reactive ClOx- formed from the reduction of ClO4-. To mitigate Re(hoz)2 decomposition and preserve catalytic activity, ruthenium (Ru) and rhodium (Rh) were evaluated as alternative H2 activators to Pd. Rh showed superior activity for reducing the ClO3- intermediate to Cl-, thereby preventing ClOx- buildup and lowering Re complex decomposition in the Re(hoz)2-Rh/C catalyst. In contrast, Ru showed the lowest ClO3- reduction activity and resulted in the most Re(hoz)2 decomposition among the Re(hoz)2-M/C catalysts. This work highlights the importance of using mechanistic insights from kinetic and spectroscopic tests to rationally design water treatment catalysts for enhanced performance and stability. PMID:26422179

  14. Alkaloid decomposition by DC pin-hole discharge in water solution

    NASA Astrophysics Data System (ADS)

    Klimova, Edita J.; Krcma, Frantisek; Jonisova, Lenka

    2016-08-01

    DC diaphragm discharge generated in a batch reactor was used to decompose two selected model alkaloids, caffeine and quinine in concentrations ranging from 10 to 50 ppm or 5 to 15 ppm, respectively. UV-vis spectrometry was utilized in evaluation of H2O2 production during the process as well as degradation of caffeine. Fluorescence spectrometry was used for quantification of quinine. High rates of decomposition were reached in both cases in the anode part of the reactor. On the other hand, up to four times lower decomposition was observed in the cathode part. Total removal efficiency gained up to 300 mg/kWh for caffeine and 210 mg/kWh for quinine. Contribution to the topical issue "6th Central European Symposium on Plasma Chemistry (CESPC-6)", edited by Nicolas Gherardi, Ester Marotta and Cristina Paradisi

  15. Localized corrosion of 316L stainless steel in tritiated water containing aggressive radiolytic and decomposition products at different temperatures

    NASA Astrophysics Data System (ADS)

    Bellanger, G.

    2008-02-01

    Tritium is one of the more important radionuclides used in nuclear industry as plutonium and uranium. The tritium in tritiated water always causes difficulties in nuclear installations, including equipment corrosion. Moreover, with tritiated water there are, in addition, the radiolytic and decomposition products such as hydrogen peroxide formed during decay, chloride ions produced by degradation of organic seals and oils used for tightness and pumping, and acid pH produced by excitation of nitrogen in air by the β - particle. Highly concentrated tritiated water releases energy and its temperature is about 80 °C, moreover heating is necessary in the tritium processes. These conditions highly facilitate the corrosion of stainless steels by pitting and crevice attack. Corrosion tests were performed by electrochemical analysis methods and by visual inspection of the surface of stainless steel.

  16. Problems of Terminology in the Teaching of Plant Water Relations

    ERIC Educational Resources Information Center

    Bradbeer, Philip A.; And Others

    1976-01-01

    Recommends use by teachers of new terminology regarding plant water relations. Includes definitions and Greek symbols for the following terms: water potential, water potential of cell, osmotic potential, matric potential, and pressure potential. (CS)

  17. Observed Global Historical Changes in Soil Decomposition Rates (1900-2011) and Plant Production (1981-2011)

    NASA Astrophysics Data System (ADS)

    Parton, W. J.; Smith, W. K.; Derner, J. D.; Del Grosso, S.; Chen, M.; Silver, W. L.

    2015-12-01

    This paper presents a unique analysis of changes in global soil decomposition rates from 1900 to 2011, determine which climatic factors have caused the observed historical changes in soil decay rates, and compares changes in soil decay rates with observed changes in plant production from 1981 to 2011. This analysis allows us to determine the impact of climatic changes from 1981 to 2011 on soil carbon (C) sequestration. We use observed global monthly global Climatic Research Unit (CRU) weather data from 1900 to 2011 (0.5° x 0.5° spatial scale) to calculate annual changes in the climatic decomposition index (CDI), an analog for soil decay rates. The CRU data was also used to calculate annual changes in precipitation, mean annual temperature, potential evapotranspiration and actual evapotranspiration (AET) rates at the 0.5° x 0.5° spatial scale. Annual changes in plant production (NPP) at the global scale were calculated using global satellite derived Normalized Difference Vegetation Index (NDVI) data sets. At the global scale CDI showed little change from 1900 to 1980 but increased by 4% from 1980 to 2011. CDI increased by more than 10% in tundra and boreal forest systems from 1980 to 2011 (< 4% for all other biomes). Changes in CDI are well correlated to changes in AET rates (r2 > 0.8) with a 2 to 4% increase in AET for most biomes (no change for dry grassland and desert biomes). NPP increased by > 6% for tundra, boreal forest and temperate forest from 1980 to 2011 with latitudinal average changes in NPP and CDI following similar patterns (greatest increases in the +40° to +75° latitudes). Global patterns in NPP are well correlated to AET and CDI (r2 > 0.8) but have different patterns (linear for AET and curvilinear for CDI). Latitudinal averaged ratio of NPP:CDI is correlated to Harmonized World Soil Database soil C levels (r = 0.67). Statistically significant trends (1980-2011) in NPP:CDI suggest increases in soil C for the boreal forest and temperate dry

  18. Improvement of water treatment at thermal power plants

    NASA Astrophysics Data System (ADS)

    Larin, B. M.; Bushuev, E. N.; Larin, A. B.; Karpychev, E. A.; Zhadan, A. V.

    2015-04-01

    Prospective and existing technologies for water treatment at thermal power plants, including pretreatment, ion exchange, and membrane method are considered. The results obtained from laboratory investigations and industrial tests of the proposed technologies carried out at different thermal power plants are presented. The possibilities of improving the process and environmental indicators of water treatment plants are shown.

  19. 11. Water treatment plant interior view of pipes, stairs, and ...

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

    11. Water treatment plant interior view of pipes, stairs, and pump in pump room. View to SW - Fort Benton Water Treatment Plant, Filtration Plant, Lots 9-13 of Block 7, Fort Benton Original Townsite at Missouri River, Fort Benton, Chouteau County, MT

  20. 12. Water treatment plant interior view of pipes and pump ...

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

    12. Water treatment plant interior view of pipes and pump in heater room. View to W - Fort Benton Water Treatment Plant, Filtration Plant, Lots 9-13 of Block 7, Fort Benton Original Townsite at Missouri River, Fort Benton, Chouteau County, MT

  1. Decomposition analysis of water footprint changes in a water-limited river basin: a case study of the Haihe River Basin, China

    NASA Astrophysics Data System (ADS)

    Zhi, Y.; Yang, Z. F.; Yin, X. A.

    2013-12-01

    Decomposition analysis of water footprint (WF) changes, or assessing the changes in WF and identifying the contributions of factors leading to the changes, is important to water resource management. However, conventional studies focus on WF from the perspective of administrative region rather than river basin. Decomposition analysis of WF changes from the perspective of the river basin is more scientific. To address this perspective, we built a framework in which the input-output (IO) model and the Structural Decomposition Analysis (SDA) model for WF could be implemented in a river basin by computing IO data for the river basin with the Generating Regional IO Tables (GRIT) method. This framework is illustrated in the Haihe River Basin (HRB), which is a typical water-limited river basin. It shows that the total WF in the HRB increased from 4.3 × 1010 m3 in 2002 to 5.6 × 1010 m3 in 2007, and the agriculture sector makes the dominant contribution to the increase. Both the WF of domestic products (internal) and the WF of imported products (external) increased, and the proportion of external WF rose from 29.1% to 34.4%. The technological effect was the dominant contributor to offsetting the increase of WF; however, the growth of WF caused by the economic structural effect and the scale effect was greater, so the total WF increased. This study provides insights about water challenges in the HRB and proposes possible strategies for the future, and serves as a reference for WF management and policy making in other water-limited river basins.

  2. A theoretical study of water adsorption and decomposition on low-index spinel ZnGa2O4 surfaces: correlation between surface structure and photocatalytic properties.

    PubMed

    Jia, Chuanyi; Fan, Weiliu; Yang, Fei; Zhao, Xian; Sun, Honggang; Li, Pan; Liu, Li

    2013-06-11

    Water adsorption and decomposition on stoichiometrically perfect and oxygen vacancy containing ZnGa2O4 (100), (110), and (111) surfaces were investigated through periodic density functional theory (DFT) calculations. The results demonstrated that water adsorption and decomposition are surface-structure-sensitive processes. On a stoichiometrically perfect surface, the most stable molecular adsorption that could take place involved the generation of hydrogen bonds. For dissociative adsorption, the adsorption energy of the (111) surface was more than 4 times the energies of the other two surfaces, indicating it to be the best surface for water decomposition. A detailed comparison of these three surfaces showed that the primary reason for this observation was the special electronic state of the (111) surface. When water dissociated on the (111) surface, the special Ga3c-4s and 4p hybridization states at the Fermi level had an obvious downshift to the lower energies. This large energy gain greatly promoted the dissociation of water. Because the generation of O(3c) vacancy defects on the (100) and (110) surfaces could increase the stability of the dissociative adsorption states with few changes to the energy barrier, this type of defect would make the decomposition of water molecules more favorable. However, for the (111) surface, the generation of vacancy defects could decrease the stability of the dissociative adsorption states and significantly increase their energy barriers. Therefore, the decomposition of water molecules on the oxygen vacancy defective (111) surface would be less favorable than the perfect (111) surface. These findings on the decomposition of H2O on the ZnGa2O4 surfaces can be used toward the synthesis of water-splitting catalysts. PMID:23682995

  3. Cadaver decomposition in terrestrial ecosystems

    NASA Astrophysics Data System (ADS)

    Carter, David O.; Yellowlees, David; Tibbett, Mark

    2007-01-01

    A dead mammal (i.e. cadaver) is a high quality resource (narrow carbon:nitrogen ratio, high water content) that releases an intense, localised pulse of carbon and nutrients into the soil upon decomposition. Despite the fact that as much as 5,000 kg of cadaver can be introduced to a square kilometre of terrestrial ecosystem each year, cadaver decomposition remains a neglected microsere. Here we review the processes associated with the introduction of cadaver-derived carbon and nutrients into soil from forensic and ecological settings to show that cadaver decomposition can have a greater, albeit localised, effect on belowground ecology than plant and faecal resources. Cadaveric materials are rapidly introduced to belowground floral and faunal communities, which results in the formation of a highly concentrated island of fertility, or cadaver decomposition island (CDI). CDIs are associated with increased soil microbial biomass, microbial activity (C mineralisation) and nematode abundance. Each CDI is an ephemeral natural disturbance that, in addition to releasing energy and nutrients to the wider ecosystem, acts as a hub by receiving these materials in the form of dead insects, exuvia and puparia, faecal matter (from scavengers, grazers and predators) and feathers (from avian scavengers and predators). As such, CDIs contribute to landscape heterogeneity. Furthermore, CDIs are a specialised habitat for a number of flies, beetles and pioneer vegetation, which enhances biodiversity in terrestrial ecosystems.

  4. A Greener Arctic: Vascular Plant Litter Input in Subarctic Peat Bogs Changes Soil Invertebrate Diets and Decomposition Patterns

    NASA Astrophysics Data System (ADS)

    Krab, E. J.; Berg, M. P.; Aerts, R.; van Logtestijn, R. S. P.; Cornelissen, H. H. C.

    2014-12-01

    Climate-change-induced trends towards shrub dominance in subarctic, moss-dominated peatlands will most likely have large effects on soil carbon (C) dynamics through an input of more easily decomposable litter. The mechanisms by which this increase in vascular litter input interacts with the abundance and diet-choice of the decomposer community to alter C-processing have, however, not yet been unraveled. We used a novel 13C tracer approach to link invertebrate species composition (Collembola), abundance and species-specific feeding behavior to C-processing of vascular and peat moss litters. We incubated different litter mixtures, 100% Sphagnum moss litter, 100% Betula leaf litter, and a 50/50 mixture of both, in mesocosms for 406 days. We revealed the transfer of C from the litters to the soil invertebrate species by 13C labeling of each of the litter types and assessed 13C signatures of the invertebrates Collembola species composition differed significantly between Sphagnum and Betula litter. Within the 'single type litter' mesocosms, Collembola species showed different 13C signatures, implying species-specific differences in diet choice. Surprisingly, the species composition and Collembola abundance changed relatively little as a consequence of Betula input to a Sphagnum based system. Their diet choice, however, changed drastically; species-specific differences in diet choice disappeared and approximately 67% of the food ingested by all Collembola originated from Betula litter. Furthermore, litter decomposition patterns corresponded to these findings; mass loss of Betula increased from 16.1% to 26.2% when decomposing in combination with Sphagnum, while Sphagnum decomposed even slower in combination with Betula litter (1.9%) than alone (4.7%). This study is the first to empirically show that collective diet shifts of the peatland decomposer community from mosses towards vascular plant litter may drive altered decomposition patterns. In addition, we showed that

  5. Aquaporins: Highly Regulated Channels Controlling Plant Water Relations1

    PubMed Central

    Chaumont, François; Tyerman, Stephen D.

    2014-01-01

    Plant growth and development are dependent on tight regulation of water movement. Water diffusion across cell membranes is facilitated by aquaporins that provide plants with the means to rapidly and reversibly modify water permeability. This is done by changing aquaporin density and activity in the membrane, including posttranslational modifications and protein interaction that act on their trafficking and gating. At the whole organ level aquaporins modify water conductance and gradients at key “gatekeeper” cell layers that impact on whole plant water flow and plant water potential. In this way they may act in concert with stomatal regulation to determine the degree of isohydry/anisohydry. Molecular, physiological, and biophysical approaches have demonstrated that variations in root and leaf hydraulic conductivity can be accounted for by aquaporins but this must be integrated with anatomical considerations. This Update integrates these data and emphasizes the central role played by aquaporins in regulating plant water relations. PMID:24449709

  6. Electrochemical decomposition of fluorinated wetting agents in plating industry waste water.

    PubMed

    Fath, Andreas; Sacher, Frank; McCaskie, John E

    2016-01-01

    Electrochemical decomposition of fluorinated surfactants (PFAS, perfluorinated alkyl substances) used in the plating industry was analyzed and the decomposition process parameters optimized at the laboratory scale and production scale of a 500-liter reactor using lead electrodes. The method and system was successfully demonstrated under production conditions to treat PFAS) with up to 99% efficiency in the concentration range of 1,000-20,000 μg/l (1 ppm-20 ppm). The treatment also reduced hexavalent chromium (Cr(6+)) ions to trivalent chromium (Cr(3+)) ions in the wastewater. If the PFAS-containing wastewater is mixed with other wastewater streams, specifically from nickel plating drag out solution or when pH values >5, the treatment process is ineffective. For the short chain PFAS, (perfluorobutylsulfonate) the process was less efficient than C6-C8 PFAS. The process is automated and has safety procedures and controls to prevent hazards. The PFAS were decomposed to hydrogen fluoride (HF) under the strong acid electrochemical operating conditions. Analytical tests showed no evidence of organic waste products remaining from the process. Conventional alternative PFAS removal systems were tested on the waste streams and compared with each other and with the-E-destruct (electrochemical oxidation) process. For example, ion exchange resin (IX resin) treatment of wastewater to complex and remove PFAS was found to be seven times more efficient when compared to the conventional activated carbon absorption (C-treat) process. However, the E-destruct process is higher in capacity, exhibits longer service life and lower operating costs than either IX or C-treat methods for elimination of PFAS from these electroplating waste streams. PMID:27054738

  7. Non-Additive Effects on Decomposition from Mixing Litter of the Invasive Mikania micrantha H.B.K. with Native Plants

    PubMed Central

    Chen, Bao-Ming; Peng, Shao-Lin; D’Antonio, Carla M.; Li, Dai-Jiang; Ren, Wen-Tao

    2013-01-01

    A common hypothesis to explain the effect of litter mixing is based on the difference in litter N content between mixed species. Although many studies have shown that litter of invasive non-native plants typically has higher N content than that of native plants in the communities they invade, there has been surprisingly little study of mixing effects during plant invasions. We address this question in south China where Mikania micrantha H.B.K., a non-native vine, with high litter N content, has invaded many forested ecosystems. We were specifically interested in whether this invader accelerated decomposition and how the strength of the litter mixing effect changes with the degree of invasion and over time during litter decomposition. Using litterbags, we evaluated the effect of mixing litter of M. micrantha with the litter of 7 native resident plants, at 3 ratios: M1 (1∶4, = exotic:native litter), M2 (1∶1) and M3 (4∶1, = exotic:native litter) over three incubation periods. We compared mixed litter with unmixed litter of the native species to identify if a non-additive effect of mixing litter existed. We found that there were positive significant non-additive effects of litter mixing on both mass loss and nutrient release. These effects changed with native species identity, mixture ratio and decay times. Overall the greatest accelerations of mixture decay and N release tended to be in the highest degree of invasion (mix ratio M3) and during the middle and final measured stages of decomposition. Contrary to expectations, the initial difference in litter N did not explain species differences in the effect of mixing but overall it appears that invasion by M. micrantha is accelerating the decomposition of native species litter. This effect on a fundamental ecosystem process could contribute to higher rates of nutrient turnover in invaded ecosystems. PMID:23840435

  8. Carbon Assimilation Pathways, Water Relationships and Plant Ecology.

    ERIC Educational Resources Information Center

    Etherington, John R.

    1988-01-01

    Discusses between-species variation in adaptation of the photosynthetic mechanism to cope with wide fluctuations of environmental water regime. Describes models for water conservation in plants and the role of photorespiration in the evolution of the different pathways. (CW)

  9. To prevent the occurrence of black water agglomerate through delaying decomposition of cyanobacterial bloom biomass by sediment microbial fuel cell.

    PubMed

    Zhou, Yan-Li; Jiang, He-Long; Cai, Hai-Yuan

    2015-04-28

    Settlement of cyanobacterial bloom biomass (CBB) into sediments in eutrophic lakes often induced the occurrence of black water agglomerate and then water quality deterioration. This study investigated the effect of sediment microbial fuel cell (SMFC) on CBB removal in sediments and related water pollution. Sediment bulking and subsequent black water from decomposition of settled CBB happened without SMFC, but were not observed over 100-day experiments with SMFC employment. While CBB in sediments improved power production from SMFC, the removal efficiency of organic matters in CBB-amended sediments with SMFC was significantly lower than that without SMFC. Pyrosequencing analysis showed higher abundances of the fermentative Clostridium and acetoclastic methanogen in CBB-amended bulk sediments without SMFC than with SMFC at the end of experiments. Obviously, SMFC operation changed the microbial community in CBB-amended sediments, and delayed the CBB degradation against sediment bulking. Thus, SMFC could be potentially applied as pollution prevention in CBB-settled and sensitive zones in shallow lakes. PMID:25621829

  10. Investigation of the loss mechanisms of hydroxyl radicals in the decomposition of organic compounds using plasma generated over water

    NASA Astrophysics Data System (ADS)

    Takeuchi, Nozomi; Ando, Mizuki; Yasuoka, Koichi

    2015-11-01

    Many types of plasma processes have been investigated as potential agents for decomposing persistent organic compounds in water using hydroxyl radicals (•OH), and a wide range of energy efficiency in the reduction of total organic carbon (TOC) has been observed. In this study, loss mechanisms of •OH that limit the energy efficiency were investigated using a plasma generated over an acetic acid solution. Various experiments, including the analysis of the decomposition process, a parametric study, and a numerical simulation, revealed that there are two main loss mechanisms: (i) a self-quenching reaction that generates hydrogen peroxide (H2O2) and (ii) a reaction of •OH with H2O2 and hydroperoxyl radicals (HO2•). In the solution, •OH reacts with these scavengers rather than target compounds. A pulsed plasma with a low current density, low repetition rate, and short pulse duration can be utilized to achieve high efficiency.

  11. PHOTOREACTIVITY OF CHROMOPHORIC DISSOLVED ORGANIC MATTER (CDOM) DERIVED FROM DECOMPOSITION OF VARIOUS VASCULAR PLANT AND ALGAL SOURCES

    EPA Science Inventory

    Chromophoric dissolved organic matter (CDOM) in aquatic environments is derived from the microbial decomposition of terrestrial and microbial organic matter. Here we present results of studies of the spectral properties and photoreactivity of the CDOM derived from several organi...

  12. Detection of Plant Water Content with Needle-Type In-Situ Water Content Sensor

    NASA Astrophysics Data System (ADS)

    Katayanagi, Hitoshi; Miki, Norihisa

    A needle-type water content sensor with a polyethersulfone (PES) polymer membrane was developed for the low-invasive, direct in-situ measurement of plant water content (PWC) in prior work. In this paper we demonstrate a measurement of plant water stress that represents the demand for water of the plant and greatly affects its sweetness. We inserted the sensor into a stalk of strawberry (Fragaria×ananassa) and soil. The variation in both the plant and the soil water content were successfully detected, which revealed the delay between variation in the plant water stress and soil water content after irrigation. Such delay could only be detected by the proposed sensor that could directly measure the variation of PWC in situ and continuously. The experiments also showed the variation in the signals as a function of detection sites and suggested that the detection sites of plant water stress need to be considered when the sensor is applied to irrigation culture.

  13. Study of water molecule decomposition in plasma by diode laser spectroscopy and optical actinometry methods

    NASA Astrophysics Data System (ADS)

    Bernatskiy, A. V.; Lagunov, V. V.; Ochkin, V. N.; Tskhai, S. N.

    2016-07-01

    The methods of diode laser radiation absorption at vibrational–rotational molecule transitions and optical actinometry with measurements of its electron emission spectra are used independently to study water molecule dissociation in glow discharge plasma in a mixture of water vapor and inert gases at reduced pressure. The methods yield close results. The dissociation reaches 98%.

  14. Measuring Plant Water Status: A Simple Method for Investigative Laboratories.

    ERIC Educational Resources Information Center

    Mansfield, Donald H.; Anderson, Jay E.

    1980-01-01

    Describes a method suitable for quantitative studies of plant water status conducted by high school or college students and the calculation of the relative water content (RWC) of a plant. Materials, methods, procedures, and results are discussed, with sample data figures provided. (CS)

  15. INTEGRATED STEEL PLANT POLLUTION STUDY FOR TOTAL RECYCLE OF WATER

    EPA Science Inventory

    The report gives results of an engineering study of five integrated U.S. steel plants to determine how each might ultimately achieve total recycle of water. The plants represent a broad cross section of plant-specific factors (e.g., size, age, location, and available space) that ...

  16. Air-cooled condensers eliminate plant water use

    SciTech Connect

    Wurtz, W.; Peltier, R.

    2008-09-15

    River or ocean water has been the mainstay for condensing turbine exhaust steam since the first steam turbine began generating electricity. A primary challenge facing today's plant developers, especially in drought-prone regions, is incorporating processes that reduce plant water use and consumption. One solution is to shed the conventional mindset that once-through cooling is the only option and adopt dry cooling technologies that reduce plant water use from a flood to a few sips. A case study at the Astoria Energy plant, New York City is described. 14 figs.

  17. Costs and water quality effects of wastewater treatment plant centralization

    SciTech Connect

    Macal, C.M.; Broomfield, B.J.

    1980-01-01

    The costs and water quality impacts of two regional configurations of municipal wastewater treatment plants in Northeastern Illinois are compared. In one configuration, several small treatment plants are consolidated into a smaller number of regional facilities. In the other, the smaller plants continue to operate. Costs for modifying the plants to obtain various levels of pollutant removal are estimated using a simulation model that considers the type of equipment existing at the plants and the costs of modifying that equipment to obtain a range of effluent levels for various pollutants. A dynamic water-quality/hydrology simulation model is used to determine the water quality effects of the various treatment technologies and pollutant levels. Cost and water quality data are combined and the cost-effectiveness of the two treatment configurations is compared. The regionalized treatment-plant configuration is found to be the more cost-effective.

  18. Development of a Heavy Water Detritiation Plant for PIK Reactor

    SciTech Connect

    Alekseev, I.A.; Bondarenko, S.D.; Fedorchenko, O.A.; Konoplev, K.A.; Vasyanina, T.V.; Arkhipov, E.A.; Uborsky, V.V

    2005-07-15

    The research reactor PIK should be supplied with a Detritiation Plant (DP) to remove tritium from heavy water in order to reduce operator radiation dose and tritium emissions. The original design of the reactor PIK Detritiation Plant was completed several years ago. A number of investigations have been made to obtain data for the DP design. Nowadays the design of the DP is being revised on a basis of our investigations. The Combined Electrolysis and Catalytic Exchange (CECE) process will be used at the Detritiation Plant instead of Vapor Phase Catalytic Exchange. The experimental industrial plant for hydrogen isotope separation on the basis of the CECE process is under operation in Petersburg Nuclear Physics Institute. The plant was updated to provide a means for heavy water detritiation. Very high detritiation factors have been achieved in the plant. The use of the CECE process will allow the development of a more compact and less expensive detritiation plant for heavy water reactor PIK.

  19. Dynamics of phosphorus-iron-sulfur at the sediment-water interface influenced by algae blooms decomposition.

    PubMed

    Han, Chao; Ding, Shiming; Yao, Lei; Shen, Qiushi; Zhu, Chungang; Wang, Yan; Xu, Di

    2015-12-30

    This study addresses the previously unknown effects of algae blooms on the dynamics of phosphorus (P), iron (Fe) and sulfur (S) across a lacustrine sediment-water interface (SWI). A mesocosm experiment was conducted in-situ to investigate these effects based on two recently-developed diffusive gradients in thin-films techniques (DGT). Soluble P, Fe(II), and S(-II) exhibited similar changing trends in a water column subject to the algae addition. Peak concentrations appeared on day 7 of the 16-day experiment. The lowest Eh occurred at the experiment's midway point indicating a strong algae degradation. A maximum increase in DGT-labile S appeared on day 8 near the SWI, while the DGT-labile P and Fe exhibited persistent increases almost to the end of experiment. Significantly positive correlations of labile P were observed switching from between labile Fe and labile S in sediments, suggesting a significant change in original Fe-coupled dynamics of P under algae decomposition. Apparent fluxes were calculated based on DGT profiles where a simultaneous release of P and S occurred from degraded algae, resulting in bidirectional diffusion fluxes from sediment to overlying water. In contrast, sediment acted as a major source of labile Fe due to added depth and apparently positive fluxes. PMID:26207579

  20. Arsenic Uptake by Muskmelon (Cucumis melo) Plants from Contaminated Water.

    PubMed

    Hettick, Bryan E; Cañas-Carrell, Jaclyn E; Martin, Kirt; French, Amanda D; Klein, David M

    2016-09-01

    Arsenic is a carcinogenic element that occurs naturally in the environment. High levels of arsenic are found in water in some parts of the world, including Texas. The aims of this study were to determine the distribution of arsenic in muskmelon (Cucumis melo) plants accumulated from arsenic spiked water and to observe effects on plant biomass. Plants were grown and irrigated using water spiked with variable concentrations of arsenic. Inductively coupled plasma mass spectrometry was used to quantify arsenic in different parts of the plant and fruit. Under all conditions tested in this study, the highest concentrations of arsenic were found in the leaves, soil, and roots. Arsenic in the water had no significant effect on plant biomass. Fruits analyzed in this study had arsenic concentrations of 101 μg/kg or less. Consuming these fruits would result in less arsenic exposure than drinking water at recommended levels. PMID:27460822

  1. Plant experience with temporary reverse osmosis makeup water systems

    SciTech Connect

    Polidoroff, C.

    1986-01-01

    Pacific Gas and Electric (PG and E) Company's Diablo Canyon Power Plant (DCPP), which is located on California's central coast, has access to three sources of raw water: creek water, well water, and seawater. Creek and well water are DCPP's primary sources of raw water; however, because their supply is limited, these sources are supplemented with seawater. The purpose of this paper is to discuss the temporary, rental, reverse osmosis systems used by PG and E to process DCPP's raw water into water suitable for plant makeup. This paper addresses the following issues: the selection of reverse osmosis over alternative water processing technologies; the decision to use vendor-operated temporary, rental, reverse osmosis equipment versus permanent PG and E-owned and -operated equipment; the performance of DCPP's rental reverse osmosis systems; and, the lessons learned from DCPP's reverse osmosis system rental experience that might be useful to other plants considering renting similar equipment.

  2. The analysis and composition of fatty material produced by the decomposition of herring in sea water

    USGS Publications Warehouse

    Wells, R.C.; Erickson, E.T.

    1933-01-01

    This paper describes the analysis of calcium and magnesium salts of fatty acids derived from herring buried under sea water, and discusses some geochemical possibilities related to the origin of petroleum in sedimentary deposits.

  3. Controlling the pathways in molecular decomposition: The vibrationally mediated photodissociation of water

    SciTech Connect

    Vander Wal, R.L.; Crim, F.F. )

    1989-07-13

    Vibrationally mediated photodissociation, in which vibrational overtone excitation prepares a single rovibrational state of water that an ultraviolet photon subsequently dissociates, permits a fully state resolved study of the photodissociation of water. Dissociating water from six different initial rotational states and detecting the OH products by laser-induced fluorescence shows that the distribution of the products among their rotational states depends strongly on the state initially selected in the vibrational overtone excitation step. These measurements also demonstrate the control of the dissociation pathway by selection of different intermediate states. Dissociating water molecules from one vibrational state ({vert bar}04>4{sup {minus}}) produces almost no vibrationally excited OH products, but dissociating another state ({vert bar}13>{sup {minus}}) that corresponds to a different nuclear motion produces roughly comparable amounts of OH(v = 1) and OH(v = O).

  4. Water resource management planning guide for Savannah River Plant

    SciTech Connect

    Hubbard, J.E.; Stephenson, D.E.; Steele, J.L. and Co., Aiken, SC . Savannah River Lab.); Gordon, D.E. and Co., Aiken, SC . Savannah River Plant)

    1988-10-01

    The Water Resource Management Planning Guide provides an outline for the development of a Savannah River Plant Water Resource Management Plan (WRMP) to protect, manage, and monitor the site's water resources. The management plan is based on three principle elements: (1) protection of the water quality, (2) management of the water quantity, and (3) monitoring of the water quality and quantity. The plan will assure that changes in water quality and quantity are identified and that corrective action is implemented as needed. In addition, water management activities within and between Savannah River Plant (SRP) organizations and departments will be coordinated to ensure the proper management of water resources. This document is intended as a guide to suggest goals and objectives that will provide a basis for the development of a water resource plan for SRP. Planning should be flexible rather than rigid, and the plan outlines in this document was prepared to be modified or updated as conditions necessitate. 16 refs., 12 figs.

  5. Kinetic analysis for ammonia decomposition in supercritical water oxidation of sewage sludge

    SciTech Connect

    Goto, Motonobu; Shiramizu, Daisuke; Kodama, Akio; Hirose, Tsutomu

    1999-11-01

    Supercritical water oxidation was applied to the destruction of municipal excess sewage sludge. The reaction was carried out in a batch reactor with hydrogen peroxide as an oxidant in the temperature range of 723--823 K. Ammonia and acetic acid are found to be refractory intermediates in supercritical water oxidation of organic wastes. Ammonia concentration produced during the reaction was measured as a function of reaction time. The dynamic data were analyzed by a first-order kinetics. The reaction rate constant coincides with those reported in the literature.

  6. Co-regulation of water and K(+) transport in sunflower plants during water stress recovery.

    PubMed

    Benlloch, Manuel; Benlloch-González, María

    2016-06-01

    16-day-old sunflower (Helianthus annuus L.) plants were subjected to deficit irrigation for 12 days. Following this period, plants were rehydrated for 2 days to study plant responses to post-stress recovery. The moderate water stress treatment applied reduced growth in all plant organs and the accumulation of K(+) in the shoot. After the rehydration period, the stem recovered its growth and reached a similar length to the control, an effect which was not observed in either root or leaves. Moreover, plant rehydration after water stress favored the accumulation of K(+) in the apical zone of the stem and expanding leaves. In the roots of plants under water stress, watering to field capacity, once the plants were de- topped, rapidly favored K(+) and water transport in the excised roots. This quick and short-lived response was not observed in roots of plants recovered from water stress for 2 days. These results suggest that the recovery of plant growth after water stress is related to coordinated water and K(+) transport from the root to the apical zone of the ​​stem and expanding leaves. This stimulation of K(+) transport in the root and its accumulation in the cells of the growing zones of the ​​stem must be one of the first responses induced in the plant during water stress recovery. PMID:27016874

  7. Resistance to Water Flow in the Sorghum Plant 1

    PubMed Central

    Meyer, Wayne S.; Ritchie, Joe T.

    1980-01-01

    Knowledge of the location and magnitude of the resistance to water flow in a plant is fundamental for describing whole plant response to water stress. The reported magnitudes of these resistances vary widely, principally because of the difficulty of measuring water potential within the plant. A number of interrelated experiments are described in which the water potential of a covered, nontranspiring leaf attached to a transpiring sorghum plant (Sorghum bicolor [L.] Moench) was used as a measure of the potential at the root-shoot junction. This allowed a descriptive evaluation of plant resistance to be made. The water potentials of a covered, nontranspiring leaf and a nonabsorbing root in solution, both attached to an otherwise actively transpiring and absorbing plant, were found to be similar. This supported the hypothesis that covered leaf water potential was equilibrating at a point shared by the vascular connections of both leaves and roots, i.e. the nodal complex of the root-shoot junction or crown. The difference in potential between a covered and exposed leaf together with calculated individual leaf transpiration rates were used to evaluate the resistance between the plant crown and the exposed leaf lamina called the connection resistance. There was an apparent decrease in the connection resistance as the transpiration rate increased; this is qualitatively explained as plant capacitance. Assuming that the covered leaf water potential was equal to that in the root xylem at the point of water absorption in the experimental plants with relatively short root axes, calculated radial root resistances were strongly dependent on the transpiration rate. For plants with moderate to high transpiration rates the roots had a slightly larger resistance than the shoots. PMID:16661138

  8. A thermochemical data bank for cycle analysis. [water decomposition for hydrogen production

    NASA Technical Reports Server (NTRS)

    Carty, R.; Funk, J.; Conger, W.; Soliman, M.; Cox, K.

    1976-01-01

    The use of the computer program PAC-2 to produce a thermodynamic data bank for various materials used in water-splitting cycles is described. The sources of raw data and a listing of 439 materials for which data are presently available are presented. This paper also discusses the use of the data bank in conjunction with two other programs, CEC-72 and HYDRGN. The integration of these three programs implement an evaluation procedure for thermochemical water splitting cycles. CEC-72 is a program used to predict the equilibrium composition of the various chemical reactions in the cycle. HYDRGN is a program which is used to calculate changes in thermodynamic properties, work of separation, amount of recycle, internal heat regeneration, total thermal energy and process thermal efficiency for a thermochemical cycle.

  9. Photochemical decomposition of organic compounds in water after UV-irradiation: investigation of positive mutagenic effects.

    PubMed

    de Veer, I; Moriske, H J; Rüden, H

    1994-06-01

    It should be investigated whether UV-disinfection of natural and contaminated organic substances in surface and drinking water may generate a positive mutagenic effect. Selected organic pesticides (atrazine, simazine, metobromurone, methabenzthiazurone, dichlorprop) and organic compounds naturally present in water (phenylalanine, tyrosine, polysaccharides) were examined in Ames-test (bacterial strains TA 98 and TA 100) and sister chromatid exchange (SCE)-test (V79 cells) before and after UV-irradiation. UV-irradiation with low- and high-pressure mercury vapor lamps was carried out in parallel experiments. Based on results in Ames- and SCE-test a mutagenic activity was not obtained for all samples, neither before nor after UV-irradiation. PMID:8202921

  10. Effect of Electrolytes on the Decomposition of Dye by Pulsed Discharge in Air Spraying Water Droplets

    NASA Astrophysics Data System (ADS)

    Nose, Taisuke; Yokoyama, Yuzo; Minamitani, Yasushi

    Effect of electrolytes on the decolorization of indigo carmine and on the production of H2O2 by pulsed discharge in air spraying water droplets was performed in sodium chloride and magnesium sulfate solutions. Peak voltage of the discharge decreased with increasing solution conductivity, but peak current and discharge energy increased. Decolorization rate and decolorization efficiency of indigo carmine and the yield of H2O2 decreased with increasing chloride and sulfate ion concentrations. It was found that the decolorization of indigo carmine and the production of H2O2 are affected by the ion concentration even in the case of discharge in air spraying water droplets. However it was less effective than that of discharge in water. Chloride ion was more effective than sulfate ion regarding the decrease of decolorization rate and the production of H2O2. Decolorization rate of indigo carmine was strongly related to the production of H2O2. These results also indicated that decolorization of indigo carmine depends on the production of hydroxyl radical.

  11. The crystallization water of gypsum rocks is a relevant water source for plants.

    PubMed

    Palacio, Sara; Azorín, José; Montserrat-Martí, Gabriel; Ferrio, Juan Pedro

    2014-01-01

    Some minerals, like gypsum, hold water in their crystalline structure. Although still unexplored, the use of such crystallization water by organisms would point to a completely new water source for life, critical under dry conditions. Here we use the fact that the isotopic composition of free water differs from gypsum crystallization water to show that plants can use crystallization water from the gypsum structure. The composition of the xylem sap of gypsum plants during summer shows closer values to gypsum crystallization water than to free soil water. Crystallization water represents a significant water source for organisms growing on gypsum, especially during summer, when it accounts for 70-90% of the water used by shallow-rooted plants. Given the widespread occurrence of gypsum in dry lands throughout the Earth and in Mars, these results may have important implications for arid land reclamation and exobiology. PMID:25130772

  12. The Role of Plant Water Storage on Water Fluxes within the Coupled Soil-Plant-Atmosphere System

    NASA Astrophysics Data System (ADS)

    Huang, C. W.; Duman, T.; Parolari, A.; Katul, G. G.

    2015-12-01

    Plant water storage (PWS) contributes to whole-plant transpiration (up to 50%), especially in large trees and during severe drought conditions. PWS also can impact water-carbon economy as well as the degree of resistance to drought. A 1-D porous media model is employed to accommodate transient water flow through the plant hydraulic system. This model provides a mechanistic representation of biophysical processes constraining water transport, accounting for plant hydraulic architecture and the nonlinear relation between stomatal aperture and leaf water potential when limited by soil water availability. Water transport within the vascular system from the stem base to the leaf-lamina is modeled using Richards's equation, parameterized with the hydraulic properties of the plant tissues. For simplicity, the conducting flow in the radial direction is not considered here and the capacitance at the leaf-lamina is assumed to be independent of leaf water potential. The water mass balance in the leaf lamina sets the upper boundary condition for the flow system, which links the leaf-level transpiration to the leaf water potential. Thus, the leaf-level gas exchange can be impacted by soil water availability through the water potential gradient from the leaf lamina to the soil, and vice versa. The root water uptake is modeled by a multi-layered macroscopic scheme to account for possible hydraulic redistribution (HR) in certain conditions. The main findings from the model calculations are that (1) HR can be diminished by the residual water potential gradient from roots to leaves at night due to aboveground capacitance, tree height, nocturnal transpiration or the combination of the three. The degree of reduction depends on the magnitude of residual water potential gradient; (2) nocturnal refilling to PWS elevates the leaf water potential that subsequently delays the onset of drought stress at the leaf; (3) Lifting water into the PWS instead of HR can be an advantageous strategy

  13. Water use, productivity and interactions among desert plants

    SciTech Connect

    Ehleringer, J.R.

    1992-11-17

    Water plays a central role affecting all aspects of the dynamics in aridland ecosystems. Productivity, stability, and competitive interactions among ecosystem components within aridlands are key processes related directly to water in deserts. The ecological studies in this project revolve around one fundamental premise: that integrated aspects of plant metabolism provide insight into the structure and function of plant communities and ecosystems. While it is difficult to extrapolate from instantaneous physiological observations to higher scales, such as whole plant performance or to interactions between plants as components of ecosystems, several key aspects of plant metabolism are scalable. Analyses of stable isotopic composition in plant tissues at natural abundance levels provide a useful tool that can provide insight into the consequences of physiological processes over temporal and spatial scales. Some plant processes continuously fractionate among light and heavy stable isotopic forms of an element; over time this results in integrated measures of plant metabolism. For example, carbon isotope fractionation during photosynthesis results in leaf carbon isotopic composition that is a measure of the set-point for photosynthetic metabolism and of water-use efficiency. Thus it provides information on the temporal scaling of a key physiological process. In contrast, hydrogen is not fractionated during water uptake through the root. Soil water availability in shallow, deep, and/or groundwater layers vary spatially; therefore hydrogen isotope ratios of xylem sap provide a direct measure of the water source currently used by a plant. The longer-term record of carbon and hydrogen isotope ratios is recorded annually in xylem tissues (tree rings). The research in this project addresses variation in stable isotopic composition of aridland plants and its consequences for plant performance and community-level interactions.

  14. A molecular dynamics study of model SI clathrate hydrates: the effect of guest size and guest-water interaction on decomposition kinetics.

    PubMed

    Das, Subhadip; Baghel, Vikesh Singh; Roy, Sudip; Kumar, Rajnish

    2015-04-14

    One of the options suggested for methane recovery from natural gas hydrates is molecular replacement of methane by suitable guests like CO2 and N2. This approach has been found to be feasible through many experimental and molecular dynamics simulation studies. However, the long term stability of the resultant hydrate needs to be evaluated; the decomposition rate of these hydrates is expected to depend on the interaction between these guest and water molecules. In this work, molecular dynamics simulation has been performed to illustrate the effect of guest molecules with different sizes and interaction strengths with water on structure I (SI) hydrate decomposition and hence the stability. The van der Waals interaction between water of hydrate cages and guest molecules is defined by Lennard Jones potential parameters. A wide range of parameter spaces has been scanned by changing the guest molecules in the SI hydrate, which acts as a model gas for occupying the small and large cages of the SI hydrate. All atomistic simulation results show that the stability of the hydrate is sensitive to the size and interaction of the guest molecules with hydrate water. The increase in the interaction of guest molecules with water stabilizes the hydrate, which in turn shows a slower rate of hydrate decomposition. Similarly guest molecules with a reasonably small (similar to Helium) or large size increase the decomposition rate. The results were also analyzed by calculating the structural order parameter to understand the dynamics of crystal structure and correlated with the release rate of guest molecules from the solid hydrate phase. The results have been explained based on the calculation of potential energies felt by guest molecules in amorphous water, hydrate bulk and hydrate-water interface regions. PMID:25767053

  15. CHANGES IN MASS AND CHEMISTRY OF PLANT ROOTS DURING LONG-TERM DECOMPOSITION ON A CHIHUAHUAN DESERT WATERSHED

    EPA Science Inventory

    We studied the spatial and temporal patterns of decomposition of roots of a desert sub-shrub, a herbaceous annual, and four species of perennial grasses at several locations on nitrogen fertilized and unfertilized transects on a Chihuahuan Desert watershed for 3.5 years. There we...

  16. Water recovery using waste heat from coal fired power plants.

    SciTech Connect

    Webb, Stephen W.; Morrow, Charles W.; Altman, Susan Jeanne; Dwyer, Brian P.

    2011-01-01

    The potential to treat non-traditional water sources using power plant waste heat in conjunction with membrane distillation is assessed. Researchers and power plant designers continue to search for ways to use that waste heat from Rankine cycle power plants to recover water thereby reducing water net water consumption. Unfortunately, waste heat from a power plant is of poor quality. Membrane distillation (MD) systems may be a technology that can use the low temperature waste heat (<100 F) to treat water. By their nature, they operate at low temperature and usually low pressure. This study investigates the use of MD to recover water from typical power plants. It looks at recovery from three heat producing locations (boiler blow down, steam diverted from bleed streams, and the cooling water system) within a power plant, providing process sketches, heat and material balances and equipment sizing for recovery schemes using MD for each of these locations. It also provides insight into life cycle cost tradeoffs between power production and incremental capital costs.

  17. Use of reclaimed water for power plant cooling.

    SciTech Connect

    Veil, J. A.; Environmental Science Division

    2007-10-16

    Freshwater demands are steadily increasing throughout the United States. As its population increases, more water is needed for domestic use (drinking, cooking, cleaning, etc.) and to supply power and food. In arid parts of the country, existing freshwater supplies are not able to meet the increasing demands for water. New water users are often forced to look to alternative sources of water to meet their needs. Over the past few years, utilities in many locations, including parts of the country not traditionally water-poor (e.g., Georgia, Maryland, Massachusetts, New York, and North Carolina) have needed to reevaluate the availability of water to meet their cooling needs. This trend will only become more extreme with time. Other trends are likely to increase pressure on freshwater supplies, too. For example, as populations increase, they will require more food. This in turn will likely increase demands for water by the agricultural sector. Another example is the recent increased interest in producing biofuels. Additional water will be required to grow more crops to serve as the raw materials for biofuels and to process the raw materials into biofuels. This report provides information about an opportunity to reuse an abundant water source -- treated municipal wastewater, also known as 'reclaimed water' -- for cooling and process water in electric generating facilities. The report was funded by the U.S. Department of Energy's (DOE's) National Energy Technology Laboratory (NETL) Innovations for Existing Plants research program (Feeley 2005). This program initiated an energy-water research effort in 2003 that includes the availability and use of 'nontraditional sources' of water for use at power plants. This report represents a unique reference for information on the use of reclaimed water for power plant cooling. In particular, the database of reclaimed water user facilities described in Chapter 2 is the first comprehensive national effort to identify and catalog those

  18. Model reduction in coupled groundwater-surface water systems - potentials and limitations of the applied proper orthogonal decomposition (POD) method

    NASA Astrophysics Data System (ADS)

    Gosses, Moritz; Moore, Catherine; Wöhling, Thomas

    2016-04-01

    The complexity of many groundwater-surface water models often results in long model run times even on today's computer systems. This becomes even more problematic in combination with the necessity of (many) repeated model runs for parameter estimation and later model purposes like predictive uncertainty analysis or monitoring network optimization. Model complexity reduction is a promising approach to reduce the computational effort of physically-based models. Its impact on the conservation of uncertainty as determined by the (more) complex model is not well known, though. A potential under-estimation of predictive uncertainty has, however, a significant impact on model applications such as model-based monitoring network optimization. Can we use model reduction techniques to significantly reduce run times of highly complex groundwater models and yet estimate accurate uncertainty levels? Our planned research project hopes to assess this question and apply model reduction to non-linear groundwater systems. Several encouraging model simplification methods have been developed in recent years. To analyze their respective performance, we will choose three different model reduction methods and apply them to both synthetic and real-world test cases to benchmark their computational efficiency and prediction accuracy. The three methods for benchmarking will be proper orthogonal decomposition (POD) (following Siade et al. 2010), the eigenmodel method (Sahuquillo et al. 1983) and inversion-based upscaling (Doherty and Christensen, 2011). In a further step, efficient model reduction methods for application to non-linear groundwater-surface water systems will be developed and applied to monitoring network optimization. In a first step we present here one variant of the implementation and benchmarking of the POD method. POD reduces model complexity by working in a subspace of the model matrices resulting from spatial discretization with the same significant eigenvalue spectrum

  19. Sacramento River Water Treatment Plant Intake Pier & Access Bridge, ...

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

    Sacramento River Water Treatment Plant Intake Pier & Access Bridge, Spanning Sacramento River approximately 175 feet west of eastern levee on river; roughly .5 mile downstream from confluence of Sacramento & American Rivers, Sacramento, Sacramento County, CA

  20. 2. VIEW NORTHEAST OF CONDENSER WATER INTAKE (LEFT), GENERATING PLANT ...

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

    2. VIEW NORTHEAST OF CONDENSER WATER INTAKE (LEFT), GENERATING PLANT AND STACK (CENTER), AND VIADUCT (EXTREME RIGHT) - Turners Falls Power & Electric Company, Hampden Station, East bank of Connecticut River, Chicopee, Hampden County, MA

  1. MICROORGANISMS AND HIGHER PLANTS FOR WASTE WATER TREATMENT

    EPA Science Inventory

    Batch experiments were conducted to compare the waste water treatment efficiencies of plant-free microbial filters with filters supporting the growth of reeds (Phragmites communis), cattail (Typha latifolia), rush (Juncus effusus), and bamboo (Bambusa multiplex). The experimental...

  2. Formate ion decomposition in water under UV irradiation at 253.7 nm.

    PubMed

    Talu, Gonca F; Diyamandoglu, Vasil

    2004-07-15

    Formate ion (HCO2-) occurs in natural waters as a result of photooxidation of humic substances. Under UV irradiation, as applied in water purification (253.7 nm), formate ion decomposed following split-rate pseudo-zero-order kinetics (k1 and k2 are initial and final rate constants, respectively). In the presence of dissolved oxygen (DO), it was found that (a) k1 < k2, (b) k1 and k2 increased with initial formate ion concentration ([HCO2-]0 = (1.73-38.3) x 10(-5) mol L(-1)) and absorbed UV intensity (Ia = (1.38-3.99) x 10(-6) mol quanta L(-1) s(-1)), and (c) k1 and k2 were relatively insensitive to initial pH (pHo = 5.41-8.97) in buffer-free solutions. Both rate constants decreased with increasing carbonate alkalinity ((0-1.0) x 10(-3) mol L(-1)) and k1 was virtually unchanged in phosphate buffer at pH0 between 5.25 and 9.92. Carbonate buffer lowered the rate of formate ion decay, possibly due to scavenging of OH* radicals. Initial rate constant k1 slightly increased with temperature (15-35 degrees C), while k2 remained unchanged. The reaction pH increased rapidly during irradiation of buffer-free NaHCO2 solution to approach an equilibrium level as [HCO2-] reached the method detection level (MDL). The pH profile of buffer-free formate ion decay was estimated using closed-system equilibrium analysis. DO utilization during UV irradiation was 0.5 mol of O2/mol of HCO2-, while nonpurgeable organic carbon (NPOC) measurements on kinetic samples closely followed the HCO2- profile, thus strongly suggesting the transformation of HCO2- -C to CO2 in the presence of DO. In DO-free water, k1 > k2 was observed. Furthermore, k(1,DO FREE) > k(1,DO) (k(1,DO) = k1) and k(2,DO FREE) < k(2,DO) (k(2,DO) = k2). The effect of dual acid solutions on HCO2- decay was examined in a mixture of NaHCO2 and sodium oxalate (Na2C2O4). HCO2- decomposed readily until [HCO2-] approximately equal to MDL but at a lower rate than in buffer-free HCO2- solutions, while C2O4(2-) remained virtually unchanged

  3. Design of an energy efficient solar powered water desalting plant

    SciTech Connect

    Nadler, M.

    1981-01-01

    A preliminary design was completed for a 6000 m/sup 3//day totally solar thermal energy powered seawater desalting plant. The objective was to design a process which would produce water at minimum cost using leading edge but commercial or near-commercial technology. Because the cost of solar energy is high, about half the cost of the plant is for solar equipment, minimum product water cost is achieved by minimizing energy consumption.

  4. Assessment of water sources to plant growth in rice based cropping systems by stable water isotopes

    NASA Astrophysics Data System (ADS)

    Mahindawansha, Amani; Kraft, Philipp; Racela, Heathcliff; Breuer, Lutz

    2016-04-01

    Rice is one of the most water-consuming crops in the world. Understanding water source utilization of rice will help us to improve water use efficiency (WUE) in paddy management. The objectives of our study are to evaluate the isotopic compositions of surface ponded water, soil water, irrigation water, groundwater, rain water and plant water and based on stable water isotope signatures to evaluate the contributions of various water sources to plant growth (wet rice, aerobic rice and maize) together with investigating the contribution of water from different soil horizons for plant growth in different maturity periods during wet and dry seasons. Finally we will compare the water balances and crop yields in both crops during both seasons and calculate the water use efficiencies. This will help to identify the most efficient water management systems in rice based cropping ecosystems using stable water isotopes. Soil samples are collected from 9 different depths at up to 60 cm in vegetative, reproductive and matured periods of plant growth together with stem samples. Soil and plant samples are extracted by cryogenic vacuum extraction. Root samples are collected up to 60 cm depth from 10 cm intercepts leading calculation of root length density and dry weight. Groundwater, surface water, rain water and irrigation water are sampled weekly. All water samples are analyzed for hydrogen and oxygen isotope ratios (d18O and dD) using Los Gatos Research DLT100. Rainfall records, ground water level, surface water level fluctuations and the amount of water irrigated in each field will be measured during the sampling period. The direct inference approach which is based on comparing isotopic compositions (dD and d18O) between plant stem water and soil water will be used to determine water sources taken up by plant. Multiple-source mass balance assessment can provide the estimated range of potential contributions of water from each soil depth to root water uptake of a crop. These

  5. 7. ONE OF THREE CIRCULATING WATER PUMPS FOR STEAM PLANT, ...

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

    7. ONE OF THREE CIRCULATING WATER PUMPS FOR STEAM PLANT, LOCATED ON FIRST FLOOR UNDER TURBINE DECK. VIEW OF PUMP LOCATED FARTHEST NORTH. November 13, 1990 - Crosscut Steam Plant, North side Salt River near Mill Avenue & Washington Street, Tempe, Maricopa County, AZ

  6. Global distribution of plant-extractable water capacity of soil

    USGS Publications Warehouse

    Dunne, K.A.; Willmott, C.J.

    1996-01-01

    Plant-extractable water capacity of soil is the amount of water that can be extracted from the soil to fulfill evapotranspiration demands. It is often assumed to be spatially invariant in large-scale computations of the soil-water balance. Empirical evidence, however, suggests that this assumption is incorrect. In this paper, we estimate the global distribution of the plant-extractable water capacity of soil. A representative soil profile, characterized by horizon (layer) particle size data and thickness, was created for each soil unit mapped by FAO (Food and Agriculture Organization of the United Nations)/Unesco. Soil organic matter was estimated empirically from climate data. Plant rooting depths and ground coverages were obtained from a vegetation characteristic data set. At each 0.5?? ?? 0.5?? grid cell where vegetation is present, unit available water capacity (cm water per cm soil) was estimated from the sand, clay, and organic content of each profile horizon, and integrated over horizon thickness. Summation of the integrated values over the lesser of profile depth and root depth produced an estimate of the plant-extractable water capacity of soil. The global average of the estimated plant-extractable water capacities of soil is 8??6 cm (Greenland, Antarctica and bare soil areas excluded). Estimates are less than 5, 10 and 15 cm - over approximately 30, 60, and 89 per cent of the area, respectively. Estimates reflect the combined effects of soil texture, soil organic content, and plant root depth or profile depth. The most influential and uncertain parameter is the depth over which the plant-extractable water capacity of soil is computed, which is usually limited by root depth. Soil texture exerts a lesser, but still substantial, influence. Organic content, except where concentrations are very high, has relatively little effect.

  7. Optical fluorescence biosensor for plant water stress detection

    NASA Astrophysics Data System (ADS)

    Chong, Jenny P. C.; Liew, O. W.; Li, B. Q.; Asundi, A. K.

    2007-05-01

    Precision farming in arable agriculture and horticulture allows conservative use of resources that are applied according to plant needs. The growing concern for sustainability in crop production has accentuated the significance of our work to develop a rapid, sensitive and non-destructive spectroscopic method for real-time monitoring of plant water stress. Elucidation of crop water status before the onset of irreversible cellular damage is critical for effective water management to ensure maximum crop yield and profit margin. A two-component bio-sensing system comprising transgenic 'Indicator Plants' and a spectrometer-linked stereoscopic microscope was developed to detect early signs of water stress before the permanent wilting point is reached. The 'Indicator Plants' are transgenic Petunia hybrida genetically engineered with a drought-responsive promoter-linked enhanced green fluorescent protein marker gene (EGFP). No EGFP fluorescence was detected prior to induction of dehydration stress. Fluorescence emission intensity increased with dehydration period and was found mainly in the stems, leaf veins and leaf tips. While fluorescence emission above endogenous background was detectable after 2 hours of water stress treatment, the plants reached permanent wilting point after 6 hours, showing that our system was able to detect water stress prior to plant entry into the stage of irreversible damage. Future work will be geared towards overcoming biological and instrument-related difficulties encountered in our initial detection system.

  8. OZONATION AND BIOLOGICAL STABILITY OF WATER IN AN OPERATING WATER TREATMENT PLANT

    EPA Science Inventory

    Ozonation of drinking water may adversely affect the biological stability of the inished water. his study was designed assess the effect of ozone as a preoxidant on the nutrient status of water treated in a full-scale water treatment plant. he study was conducted over a ten week ...

  9. Phase field modelling of spinodal decomposition in the oil/water/asphaltene system.

    PubMed

    Tóth, Gyula I; Kvamme, Bjørn

    2015-08-21

    In this paper the quantitative applicability of van der Sman/van der Graaf type Ginzburg-Landau theories of surfactant assisted phase separation [van der Sman et al., Rheol. Acta, 2006, 46, 3] is studied for real systems displaying high surfactant concentrations at the liquid-liquid interface. The model is applied for the water/heptane/asphaltene system (a model of heavy crude oil), for which recent molecular dynamics (MD) simulations provide microscopic data needed to calibrate the theory. A list of general requirements is set up first, which is then followed by analytical calculations of the equilibrium properties of the system, such as the equilibrium liquid densities, the adsorption isotherm and the interfacial tension. Based on the results of these calculations, the model parameters are then determined numerically, yielding a reasonable reproduction of the MD density profiles. The results of time-dependent simulations addressing the dynamical behaviour of the system will also be presented. It will be shown that the competition between the diffusion and hydrodynamic time scales can lead to the formation of an emulsion. We also address the main difficulties and limitations of the theory regarding quantitative modelling of surfactant assisted liquid phase separation. PMID:26185915

  10. [A field study of tundra plant litter decomposition rate via mass loss and carbon dioxide emission: the role of biotic and abiotic controls, biotope, season of year, and spatial-temporal scale].

    PubMed

    Pochikalov, A V; Karelin, D V

    2014-01-01

    Although many recently published original papers and reviews deal with plant matter decomposition rates and their controls, we are still very short in understanding of these processes in boreal and high latiude plant communities, especially in permafrost areas of our planet. First and foremost, this is holds true for winter period. Here, we present the results of 2-year field observations in south taiga and south shrub tundra ecosystems in European Russia. We pioneered in simultaneous application of two independent methods: classic mass loss estimation by litter-bag technique, and direct measurement of CO2 emission (respiration) of the same litter bags with different types of dead plant matter. Such an approach let us to reconstruct intra-seasonal dynamics of decomposition rates of the main tundra litter fractions with high temporal resolution, to estimate the partial role of different seasons and defragmentation in the process of plant matter decomposition, and to determine its factors under different temporal scale. PMID:25771676

  11. DOSE CONTROLLER FOR AGUACLARA WATER TREATMENT PLANTS

    EPA Science Inventory

    The expected results include a proven design for a gravity powered dose controller that works for calcium hypochlorite or aluminum sulfate solutions. The dose controller will be coupled with plant flow rate measuring systems that have compatible relationships between flow rate...

  12. Application of 2D-Nonlinear Shallow Water Model of Tsunami by using Adomian Decomposition Method

    SciTech Connect

    Waewcharoen, Sribudh; Boonyapibanwong, Supachai; Koonprasert, Sanoe

    2008-09-01

    One of the most important questions in tsunami modeling is the estimation of tsunami run-up heights at different points along a coastline. Methods for numerical simulation of tsunami wave propagation in deep and shallow seas are well developed and have been widely used by many scientists (2001-2008). In this paper, we consider a two-dimensional nonlinear shallow water model of tsunami given by Tivon Jacobson is work [1]. u{sub t}+uu{sub x}+{nu}u{sub y} -c{sup 2}(h{sub x}+(h{sub b}){sub x}) {nu}{sub t}+u{nu}{sub x}+{nu}{nu}{sub y} = -c{sup 2}(h{sub y}+(h{sub b}){sub y}) h{sub t}+(hu){sub x}+(h{nu}){sub y} = 0 g-shore, h is surface elevation and s, t is time, u is velocity of cross-shore, {nu} is velocity of along-shore, h is surface elevation and h{sub b} is function of shore. This is a nondimensionalized model with the gravity g and constant reference depth H factored into c = {radical}(gH). We apply the Adomian Decompostion Method (ADM) to solve the tsunami model. This powerful method has been used to obtain explicit and numerical solutions of three types of diffusion-convection-reaction (DECR) equations. The ADM results for the tsunami model yield analytical solutions in terms of a rapidly convergent infinite power series. Symbolic computation, numerical results and graphs of solutions are obtained by Maple program.

  13. Influence of decomposition on chemical properties of plant- and manure-derived dissolved organic matter and sorption to goethite.

    PubMed

    Hunt, James F; Ohno, Tsutomu; He, Zhongqi; Honeycutt, C Wayne; Dail, D Bryan

    2007-01-01

    Sorption of dissolved organic matter (DOM) plays an important role in maintaining the fertility and quality of soils in agricultural ecosystems. Few studies have examined the effects of decomposition on DOM sorption and chemical characteristics. This study investigated the sorption to goethite (alpha-FeOOH) of fresh and decomposed hydrophilic (HPL) and hydrophobic (HPB) DOM fractions extracted from the shoots and roots of crimson clover (Trifolium incarnatum L.), corn (Zea mays L.), soybean [Glycine max (L.) Merr.], hairy vetch (Vicia villosa L.), and dairy and poultry manures. Sorption was positively related to apparent molecular weight (MWAP), aromaticity as measured by absorptivity at 280 nm, and phenolic acid content. A 10-d laboratory microbial decomposition of the source organic matter generally increased the sorption of the extracted DOM onto goethite. The decomposition effect on sorption was greater for the HPL fractions than for the HPB fractions. There was a decrease in the MWAP values of the DOM samples following sorption to goethite. In many cases the reduction in MWAP was large, indicating a strong preference by goethite for the higher MWAP DOM fractions. The results of this laboratory-based research demonstrate that microbial processes affect the chemical characteristics of DOM which may affect the distribution of soil organic C pools. PMID:17215221

  14. Lignocellulose decomposition by microbial secretions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Carbon storage in terrestrial ecosystems is contingent upon the natural resistance of plant cell wall polymers to rapid biological degradation. Nevertheless, certain microorganisms have evolved remarkable means to overcome this natural resistance. Lignocellulose decomposition by microorganisms com...

  15. Prediction of the effects of nutrient loadings from a power plant at Perryman on the water quality of the Bush River estuary. Final report

    SciTech Connect

    Rose, K.A.; Dwyer, R.L.; Turner, M.A.

    1986-10-01

    A water-quality model consisting of a one-dimensional Hydraulic Module coupled with a Water Quality Module was used to assess the effects of increased nutrient loadings from the proposed Perryman Power Plant on the dissolved oxygen and chlorophyll-a concentrations in the Bush River estuary. The Hydraulic Module represented the longitudinal water movement (and physical transport of associated constituents) among 12 spatial segments. The Water Quality Module represented the biological processes affecting nitrogen, phosphorus, chlorophyll-a, and dissolved oxygen in each segment (e.g., photosynthesis, nutrient uptake, decomposition).

  16. Ozone decomposition

    PubMed Central

    Batakliev, Todor; Georgiev, Vladimir; Anachkov, Metody; Rakovsky, Slavcho

    2014-01-01

    Catalytic ozone decomposition is of great significance because ozone is a toxic substance commonly found or generated in human environments (aircraft cabins, offices with photocopiers, laser printers, sterilizers). Considerable work has been done on ozone decomposition reported in the literature. This review provides a comprehensive summary of the literature, concentrating on analysis of the physico-chemical properties, synthesis and catalytic decomposition of ozone. This is supplemented by a review on kinetics and catalyst characterization which ties together the previously reported results. Noble metals and oxides of transition metals have been found to be the most active substances for ozone decomposition. The high price of precious metals stimulated the use of metal oxide catalysts and particularly the catalysts based on manganese oxide. It has been determined that the kinetics of ozone decomposition is of first order importance. A mechanism of the reaction of catalytic ozone decomposition is discussed, based on detailed spectroscopic investigations of the catalytic surface, showing the existence of peroxide and superoxide surface intermediates. PMID:26109880

  17. Ozone decomposition.

    PubMed

    Batakliev, Todor; Georgiev, Vladimir; Anachkov, Metody; Rakovsky, Slavcho; Zaikov, Gennadi E

    2014-06-01

    Catalytic ozone decomposition is of great significance because ozone is a toxic substance commonly found or generated in human environments (aircraft cabins, offices with photocopiers, laser printers, sterilizers). Considerable work has been done on ozone decomposition reported in the literature. This review provides a comprehensive summary of the literature, concentrating on analysis of the physico-chemical properties, synthesis and catalytic decomposition of ozone. This is supplemented by a review on kinetics and catalyst characterization which ties together the previously reported results. Noble metals and oxides of transition metals have been found to be the most active substances for ozone decomposition. The high price of precious metals stimulated the use of metal oxide catalysts and particularly the catalysts based on manganese oxide. It has been determined that the kinetics of ozone decomposition is of first order importance. A mechanism of the reaction of catalytic ozone decomposition is discussed, based on detailed spectroscopic investigations of the catalytic surface, showing the existence of peroxide and superoxide surface intermediates. PMID:26109880

  18. Water recovery in a concentrated solar power plant

    NASA Astrophysics Data System (ADS)

    Raza, Aikifa; Higgo, Alex R.; Alobaidli, Abdulaziz; Zhang, TieJun

    2016-05-01

    For CSP plants, water consumption is undergoing increasing scrutiny particularly in dry and arid regions with water scarcity conditions. Significant amount of water has to be used for parabolic trough mirror cleaning to maintain high mirror reflectance and optical efficiency in sandy environment. For this specific purpose, solar collectors are washed once or twice every week at Shams 1, one of the largest CSP plant in the Middle East, and about 5 million gallons of demineralized water is utilized every year without further recovery. The produced waste water from a CSP plant contains the soiling i.e. accumulated dust and some amount of organic contaminants, as indicated by our analysis of waste water samples from the solar field. We thus need to develop a membrane based system to filter fine dust particulates and to degrade organic contaminant simultaneously. Membrane filtration technology is considered to be cost-effective way to address the emerging problem of a clean water shortage, and to reuse the filtered water after cleaning solar collectors. But there are some major technical barriers to improve the robustness and energy efficiency of filtration membranes especially when dealing with the removal of ultra-small particles and oil traces. Herein, we proposed a robust and scalable nanostructured inorganic microporous filtration copper mesh. The inorganic membrane surface wettability is tailored to enhance the water permeability and filtration flux by creating nanostructures. These nanostructured membranes were successfully employed to recover water collected after cleaning the reflectors of solar field of Shams 1. Another achievement was to remove the traces of heat transfer fluid (HTF) from run-off water which was collected after accidental leakage in some of the heat exchangers during the commissioning of the Shams 1 for safe disposal into the main stream. We hope, by controlling the water recovery factor and membrane reusability performance, the membrane

  19. Phosphate Removal and Recovery using Drinking Water Plant Waste Residuals

    EPA Science Inventory

    Water treatment plants are used to provide safe drinking water. In parallel, however, they also produce a wide variety of waste products which, in principle, could be possible candidates as resources for different applications. Calcium carbonate is one of such residual waste in ...

  20. ARSENIC REMOVAL FROM DRINKING WATER BY IRON REMOVAL PLANTS

    EPA Science Inventory

    This report documents a long term performance study of two iron removal water treatment plants to remove arsenic from drinking water sources. Performance information was collected from one system located in midwest for one full year and at the second system located in the farwest...

  1. INORGANIC CHEMICAL CHARACTERIZATION OF WATER TREATMENT PLANT RESIDUALS

    EPA Science Inventory

    The study obtained field data on the inorganic contaminants and constituents in residuals produced by Water Treatment Plants (WTPs). Eight WTPs were studied based on treatment technology, contamination or suspected contamination of raw water, and efficiency in the removal of cont...

  2. Plants for water recycling, oxygen regeneration and food production.

    PubMed

    Bubenheim, D L

    1991-10-01

    During long-duration space missions that require recycling and regeneration of life support materials the major human wastes to be converted to usable forms are CO2, hygiene water, urine and feces. A Controlled Ecological Life Support System (CELSS) relies on the air revitalization, water purification and food production capabilities of higher plants to rejuvenate human wastes and replenish the life support materials. The key processes in such a system are photosynthesis, whereby green plants utilize light energy to produce food and oxygen while removing CO2 from the atmosphere, and transpiration, the evaporation of water from the plant. CELSS research has emphasized the food production capacity and efforts to minimize the area/volume of higher plants required to satisfy all human life support needs. Plants are a dynamic system capable of being manipulated to favour the supply of individual products as desired. The size and energy required for a CELSS that provides virtually all human needs are determined by the food production capacity. Growing conditions maximizing food production do not maximize transpiration of water; conditions favoring transpiration and scaling to recycle only water significantly reduces the area, volume, and energy inputs per person. Likewise, system size can be adjusted to satisfy the air regeneration needs. Requirements of a waste management system supplying inputs to maintain maximum plant productivity are clear. The ability of plants to play an active role in waste processing and the consequence in terms of degraded plant performance are not well characterized. Plant-based life support systems represent the only potential for self sufficiency and food production in an extra-terrestrial habitat. PMID:11537696

  3. Plants for water recycling, oxygen regeneration and food production

    NASA Technical Reports Server (NTRS)

    Bubenheim, D. L.

    1991-01-01

    During long-duration space missions that require recycling and regeneration of life support materials the major human wastes to be converted to usable forms are CO2, hygiene water, urine and feces. A Controlled Ecological Life Support System (CELSS) relies on the air revitalization, water purification and food production capabilities of higher plants to rejuvenate human wastes and replenish the life support materials. The key processes in such a system are photosynthesis, whereby green plants utilize light energy to produce food and oxygen while removing CO2 from the atmosphere, and transpiration, the evaporation of water from the plant. CELSS research has emphasized the food production capacity and efforts to minimize the area/volume of higher plants required to satisfy all human life support needs. Plants are a dynamic system capable of being manipulated to favour the supply of individual products as desired. The size and energy required for a CELSS that provides virtually all human needs are determined by the food production capacity. Growing conditions maximizing food production do not maximize transpiration of water; conditions favoring transpiration and scaling to recycle only water significantly reduces the area, volume, and energy inputs per person. Likewise, system size can be adjusted to satisfy the air regeneration needs. Requirements of a waste management system supplying inputs to maintain maximum plant productivity are clear. The ability of plants to play an active role in waste processing and the consequence in terms of degraded plant performance are not well characterized. Plant-based life support systems represent the only potential for self sufficiency and food production in an extra-terrestrial habitat.

  4. Soluble arsenic removal at water treatment plants

    SciTech Connect

    McNeill, L.S.; Edwards, M.

    1995-04-01

    Arsenic profiles were obtained from full-scale conventional treatment (coagulation, Fe-Mn oxidation, or softening) plants, facilitating testing of theories regarding arsenic removal. Soluble As(V) removal efficiency was controlled primarily by pH during coagulation, be Fe{sup +2} oxidation and Fe(OH){sub 3} precipitation during Fe-Mn oxidation, and by Mg(OH){sub 2} formation during softening. Insignificant soluble As(V) removal occurred during calcite precipitation at softening plants or during Mn{sup +2} oxidation-precipitation at Fe-Mn oxidation plants. The extent of soluble As(V) removal during coagulation and softening treatments was lower than expected. Somewhat surprisingly, during coagulation As(V) removal efficiencies were limited by particulate aluminum formation and removal, because much of the added coagulant was not removed by 0.45-{mu}m-pore-size filters. At one utility, reducing the coagulation pH from 7.4 to 6.8 (at constant alum dose) improved removal of particulate aluminum, thereby enhancing soluble As(V) removal during treatment.

  5. Investigating water transport through the xylem network in vascular plants.

    PubMed

    Kim, Hae Koo; Park, Joonghyuk; Hwang, Ildoo

    2014-04-01

    Our understanding of physical and physiological mechanisms depends on the development of advanced technologies and tools to prove or re-evaluate established theories, and test new hypotheses. Water flow in land plants is a fascinating phenomenon, a vital component of the water cycle, and essential for life on Earth. The cohesion-tension theory (CTT), formulated more than a century ago and based on the physical properties of water, laid the foundation for our understanding of water transport in vascular plants. Numerous experimental tools have since been developed to evaluate various aspects of the CTT, such as the existence of negative hydrostatic pressure. This review focuses on the evolution of the experimental methods used to study water transport in plants, and summarizes the different ways to investigate the diversity of the xylem network structure and sap flow dynamics in various species. As water transport is documented at different scales, from the level of single conduits to entire plants, it is critical that new results be subjected to systematic cross-validation and that findings based on different organs be integrated at the whole-plant level. We also discuss the functional trade-offs between optimizing hydraulic efficiency and maintaining the safety of the entire transport system. Furthermore, we evaluate future directions in sap flow research and highlight the importance of integrating the combined effects of various levels of hydraulic regulation. PMID:24609652

  6. A simple route to water-soluble size-tunable monodispersed Pd nanoparticles from light decomposition of Pd(PPh 3) 4

    NASA Astrophysics Data System (ADS)

    Tan, Hua; Zhan, Tong; Fan, Wai Yip

    2006-09-01

    Water-soluble monodispersed palladium nanoparticles of diameters 2.5, 5 and 10 nm controlled by varying the concentration of CTAB (hexadecyltrimethylammonium bromide) micelles have been prepared from light decomposition of Pd(PPh 3) 4. The size and structure of these single crystalline particles have been confirmed using UV-vis spectroscopy, high resolution transmission electron microscope, energy dispersive X-ray analysis and powder X-ray diffraction methods.

  7. Water vulnerabilities for existing coal-fired power plants.

    SciTech Connect

    Elcock, D.; Kuiper, J.; Environmental Science Division

    2010-08-19

    This report was funded by the U.S. Department of Energy's (DOE's) National Energy Technology Laboratory (NETL) Existing Plants Research Program, which has an energy-water research effort that focuses on water use at power plants. This study complements the Existing Plants Research Program's overall research effort by evaluating water issues that could impact power plants. Water consumption by all users in the United States over the 2005-2030 time period is projected to increase by about 7% (from about 108 billion gallons per day [bgd] to about 115 bgd) (Elcock 2010). By contrast, water consumption by coal-fired power plants over this period is projected to increase by about 21% (from about 2.4 to about 2.9 bgd) (NETL 2009b). The high projected demand for water by power plants, which is expected to increase even further as carbon-capture equipment is installed, combined with decreasing freshwater supplies in many areas, suggests that certain coal-fired plants may be particularly vulnerable to potential water demand-supply conflicts. If not addressed, these conflicts could limit power generation and lead to power disruptions or increased consumer costs. The identification of existing coal-fired plants that are vulnerable to water demand and supply concerns, along with an analysis of information about their cooling systems and related characteristics, provides information to help focus future research and development (R&D) efforts to help ensure that coal-fired generation demands are met in a cost-effective manner that supports sustainable water use. This study identified coal-fired power plants that are considered vulnerable to water demand and supply issues by using a geographical information system (GIS) that facilitated the analysis of plant-specific data for more than 500 plants in the NETL's Coal Power Plant Database (CPPDB) (NETL 2007a) simultaneously with 18 indicators of water demand and supply. Two types of demand indicators were evaluated. The first type

  8. USE of mine pool water for power plant cooling.

    SciTech Connect

    Veil, J. A.; Kupar, J. M .; Puder, M. G.

    2006-11-27

    Water and energy production issues intersect in numerous ways. Water is produced along with oil and gas, water runs off of or accumulates in coal mines, and water is needed to operate steam electric power plants and hydropower generating facilities. However, water and energy are often not in the proper balance. For example, even if water is available in sufficient quantities, it may not have the physical and chemical characteristics suitable for energy or other uses. This report provides preliminary information about an opportunity to reuse an overabundant water source--ground water accumulated in underground coal mines--for cooling and process water in electric generating facilities. The report was funded by the U.S. Department of Energy's (DOE's) National Energy Technology Laboratory (NETL), which has implemented a water/energy research program (Feeley and Ramezan 2003). Among the topics studied under that program is the availability and use of ''non-traditional sources'' of water for use at power plants. This report supports NETL's water/energy research program.

  9. Critical issues with cryogenic water extraction for tracing plant's source water

    NASA Astrophysics Data System (ADS)

    Orlowski, Natalie; Winkler, Anna; McDonnell, Jeffrey J.; Breuer, Lutz

    2016-04-01

    Numerous scientists and disciplines around the world are applying stable water isotope techniques-, especially in the ecohydrological context. For more than two decades, cryogenic vacuum extraction has been the most widely used method for obtaining water from soils and plant tissues for isotope analysis. Recent findings suggested that cryogenic extraction conditions (extraction time, temperature, vacuum threshold) and physicochemical soil properties considerably affected the extracted soil water isotope results. The key question therefore is: Which soil water pool/s are we actually extracting cryogenically under certain extraction conditions and is this soil water pool the source of plant water uptake? We conducted a greenhouse trial with two different plant species grown on two physicochemically different soils (sandy soil and clayey loam) to test the effects of varying cryogenic extraction conditions and physicochemical soil properties on extracted soil water isotope results. We further aimed to identify the unique soil water isotopic signature which mirrors plant's water source. We sampled root crowns and an aliquot of the first and second soil layer for cryogenic water extraction. To determine the plant water available soil water pool/s, we varied water extraction parameters (time and temperature). Our dual-isotope study showed that physicochemical soil properties (i.e. clay content, pore size) along with extraction parameters lead to isotope fractionation effects of soil water. Extraction temperature and time significantly impacted isotope results of clayey loam samples but no effect could be observed for the sandy soil. In general, for water extracts of both soil types, longer extraction times and higher temperatures resulted in enriched isotopic signatures, although this influence was more pronounced for the clayey loam. Determining ideal soil water extraction parameters to identify plant available soil water pools revealed that extraction settings of 200

  10. Water relations of riparian plants from warm desert regions

    USGS Publications Warehouse

    Smith, S.D.; Devitt, Dale A.; Cleverly, James R.; Busch, David E.

    1998-01-01

    Riparian plants have been classified as 'drought avoiders' due to their access to an abundant subsurface water supply. Recent water-relations research that tracks water sources of riparian plants using the stable isotopes of water suggests that many plants of the riparian zone use ground water rather than stream water, and not all riparian plants are obligate phreatophytes (dependent on ground water as a moisture source) but may occasionally be dependent of unsaturated soil moisture sources. A more thorough understanding of riparian plant-water relations must include water-source dynamics and how those dynamics vary over both space and time. Many rivers in the desert Southwest have been invaded by the exotic shrub Tamarix ramosissima (saltcedar). Our studies of Tamarix invasion into habitats formerly dominated by native riparian forests of primarily Populus and Salix have shown that Tamarix successfully invades these habitats because of its (1) greater tolerance to water stress and salinity, (2) status as a facultative, rather than obligate, phreatophyte and, therefore, its ability to recover from droughts and periods of ground-water drawdown, and (3) superior regrowth after fire. Analysis of water- loss rates indicate that Tamarix-dominated stands can have extremely high evapotranspiration rates when water tables are high but not necessarily when water tables are lower. Tamarix has leaf-level transpiration rates that are comparable to native species, whereas sap-flow rates per unit sapwood area are higher than in natives, suggesting that Tamarix maintains higher leaf area than can natives, probably due to its greater water stress tolerance. Tamarix desiccates and salinizes floodplains, due to its salt exudation and high transpiration rates, and may also accelerate fire cycles, thus predisposing these ecosystems to further loss of native taxa. Riparian species on regulated rivers can be exposed to seasonal water stress due to depression of floodplain water tables

  11. Decomposition techniques

    USGS Publications Warehouse

    Chao, T.T.; Sanzolone, R.F.

    1992-01-01

    Sample decomposition is a fundamental and integral step in the procedure of geochemical analysis. It is often the limiting factor to sample throughput, especially with the recent application of the fast and modern multi-element measurement instrumentation. The complexity of geological materials makes it necessary to choose the sample decomposition technique that is compatible with the specific objective of the analysis. When selecting a decomposition technique, consideration should be given to the chemical and mineralogical characteristics of the sample, elements to be determined, precision and accuracy requirements, sample throughput, technical capability of personnel, and time constraints. This paper addresses these concerns and discusses the attributes and limitations of many techniques of sample decomposition along with examples of their application to geochemical analysis. The chemical properties of reagents as to their function as decomposition agents are also reviewed. The section on acid dissolution techniques addresses the various inorganic acids that are used individually or in combination in both open and closed systems. Fluxes used in sample fusion are discussed. The promising microwave-oven technology and the emerging field of automation are also examined. A section on applications highlights the use of decomposition techniques for the determination of Au, platinum group elements (PGEs), Hg, U, hydride-forming elements, rare earth elements (REEs), and multi-elements in geological materials. Partial dissolution techniques used for geochemical exploration which have been treated in detail elsewhere are not discussed here; nor are fire-assaying for noble metals and decomposition techniques for X-ray fluorescence or nuclear methods be discussed. ?? 1992.

  12. Wetlands: Water, Wildlife, Plants, and People.

    ERIC Educational Resources Information Center

    Vandas, Steve

    1992-01-01

    Describes wetlands and explains their importance to man and ecology. Delineates the role of water in wetlands. Describes how wetlands are classified: estuarine, riverine, lacustrine, palustrine, and marine. Accompanying article is a large, color poster on wetlands. Describes an activity where metaphors are used to explore the functions of…

  13. An index for plant water deficit based on root-weighted soil water content

    NASA Astrophysics Data System (ADS)

    Shi, Jianchu; Li, Sen; Zuo, Qiang; Ben-Gal, Alon

    2015-03-01

    Governed by atmospheric demand, soil water conditions and plant characteristics, plant water status is dynamic, complex, and fundamental to efficient agricultural water management. To explore a centralized signal for the evaluation of plant water status based on soil water status, two greenhouse experiments investigating the effect of the relative distribution between soil water and roots on wheat and rice were conducted. Due to the significant offset between the distributions of soil water and roots, wheat receiving subsurface irrigation suffered more from drought than wheat under surface irrigation, even when the arithmetic averaged soil water content (SWC) in the root zone was higher. A significant relationship was found between the plant water deficit index (PWDI) and the root-weighted (rather than the arithmetic) average SWC over root zone. The traditional soil-based approach for the estimation of PWDI was improved by replacing the arithmetic averaged SWC with the root-weighted SWC to take the effect of the relative distribution between soil water and roots into consideration. These results should be beneficial for scheduling irrigation, as well as for evaluating plant water consumption and root density profile.

  14. [Mercury dynamics of several plants collected from the water-level fluctuation zone of the Three Gorges Reservoir area during flooding and its impact on water body].

    PubMed

    Zhang, Xiang; Zhang, Cheng; Sun, Rong-guo; Wang, Ding-yong

    2014-12-01

    Submerged plants are a major source for the abnormal elevation of methylmercury in reservoir. Several specific plants (Echinochloa crusgalli, Cynodondactylon and Corn stover) were collected and inundated in a simulated aquatic environment in the laboratory for investigating the mercury (Hg) dynamics in plants and the release process into water, aiming to find out the properties of Hg dynamics of plants under inundation conditions and its impact on water body in the Water-Level Fluctuation Zone of the Three Gorges Reservoir Area. The results showed that the contents of total mercury in several plants were in the range of 9. 21-12.07 ng x g(-1), and the percentage content of methylmercury (MeHg) was about 1%-2%. The content of total mercury (THg) in plants gradually decreased, by 35.81%-55.96%, whereas that of the dissolved mercury (DHg) increased sharply, by 103.23% -232.15%, which indicated an emission of Hg from plants to water in the process of decomposition. Furthermore, the state of inundation provided sufficient conditions for the methylation process in plants and therefore caused an increase of the content of methylmercury in the plant residues, which was 3.04-6.63 times as much as the initial content. The concentration of dissolved methylmercury (DMeHg) in the overlying water also increased significantly by 14.84- 16.05 times compared with the initial concentration. Meanwhile, the concentration of dissolved oxygen (DO) in the overlying water was significantly and negatively correlated with DMeHg. On the other hand, the concentration of dissolved organic carbon (DOC) in the overlying water was significantly and positively correlated with DMeHg. During the whole inundation period, the increase of DHg in the overlying water accounted for 41.74% -47.01% of the total amount of THg emission, and there was a negative correlation between the content of THg in plant residues and that of DHg in the overlying water. PMID:25826925

  15. Plants Clean Air and Water for Indoor Environments

    NASA Technical Reports Server (NTRS)

    2007-01-01

    Wolverton Environmental Services Inc., founded by longtime government environmental scientist B.C. "Bill" Wolverton, is an environmental consulting firm that gives customers access to the results of his decades of cutting-edge bioremediation research. Findings about how to use plants to improve indoor air quality have been published in dozens of NASA technical papers and in the book, "How to Grow Fresh Air: 50 Houseplants That Purify Your Home or Office." The book has now been translated into 12 languages and has been on the shelves of bookstores for nearly 10 years. A companion book, "Growing Clean Water: Nature's Solution to Water Pollution," explains how plants can clean waste water. Other discoveries include that the more air that is allowed to circulate through the roots of the plants, the more effective they are at cleaning polluted air; and that plants play a psychological role in welfare in that people recover from illness faster in the presence of plants. Wolverton Environmental is also working in partnership with Syracuse University, to engineer systems consisting of modular wicking filters tied into duct work and water supplies, essentially tying plant-based filters into heating, ventilation, and air conditioning (HVAC) systems. Also, the company has recently begun to assess the ability of the EcoPlanter to remove formaldehyde from interior environments. Wolverton Environmental is also in talks with designers of the new Stennis Visitor's Center, who are interested in using its designs for indoor air-quality filters

  16. Loop chiller plant design dramatically lowers chilled water costs

    SciTech Connect

    Hartman, T.

    1999-07-01

    Recent improvements in HVAC networking and speed control technologies, together with an improved understanding of the nature of cooling loads in buildings offer exciting opportunities for improving the energy efficiency of chiller plants. A new Loop chiller plant design has been developed that incorporates variable speed control on all plant components. Operation of this cooling plant is coordinated with the load it serves through a control network. This new approach has enormous advantages over traditional optimized plants. The two key advantages of these new Loop design chiller plants designs are: (1) Annual operating energy requirements are reduced by as much as 50% or more when compared to present state-of-the-art optimized chiller plants, and (2) A smaller sized and therefore less costly chiller plant can be designed to serve HVAC loads. The term Loop is employed to describe the technologies employed because the concept employs closed loop control by providing operational feedback from each point of use to the plant. The Loop concept also employs a single, series coupled chilled water loop for higher pumping and distribution efficiencies. This paper presents background and design theory and follows with a case study to introduce the new Loop design and operations concept. Specifics of an actual design are presented along with an explanation of how the principles can be applied economically to all new or existing chiller plant designs to achieve dramatic reductions in both construction costs and energy costs.

  17. On photochemistry of water in solid Xe: Thermal and light-induced decomposition of HXeOH and HXeH and formation of H2O2

    NASA Astrophysics Data System (ADS)

    Khriachtchev, Leonid; Tanskanen, Hanna; Pettersson, Mika; Räsänen, Markku; Ahokas, Jussi; Kunttu, Henrik; Feldman, Vladimir

    2002-04-01

    A photochemical study of water (H2 16O, H2 18O, D2 16O, and D2 18O) in solid Xe is described. The water-Xe samples were irradiated at 193 nm and then annealed at 40-50 K, which led to formation of various isotopomers of Xe-containing molecules, HXeOH and HXeH. This diffusion-controlled formation of HXeH and HXeOH consumes the main part of hydrogen atoms generated in the matrix during photolysis. Both photodecomposition profiles and ultraviolet (UV) absorption spectra of HXeOH and HXeH feature a broad absorption band of these species around 240 nm corresponding to the transition to the repulsive excited states. It is also found that HXeOH and HXeH molecules can be thermally destroyed in similar time scales of ˜10 min at about 54 and 66 K, respectively. This clear difference between the decomposition temperatures for HXeOH and HXeH suggests the intrinsic basis of the decomposition process, which possibly occurs over the barriers of the bending coordinates. The absence of strong H-D isotope effect in this thermal decomposition indicates that tunneling of hydrogen is not essentially involved in the process at these temperatures. However, the local disorder of a Xe matrix seems to produce inhomogeneous broadening of the activation energies of the decomposition as indicated by the observed nonexponential decay kinetics. Upon photolysis and annealing of the H2O-Xe samples, monomeric and complexed hydrogen peroxide is formed originating, at least partially, from water clusters stabilized in solid Xe. In addition, we report the vibrational data on various isotopomers of HXeH, HXeOH, H2O, OH, and OH⋯H2O isolated in solid Xe.

  18. [Plant growth with limited water]. Performance report

    SciTech Connect

    Not Available

    1992-10-01

    When water is in short supply, soybean stem growth is inhibited by a physical limitation followed in a few hours by metabolic changes that reduce the extensibility of the cell walls. The extensibility then becomes the main limitation. With time, there is a modest recovery in extensibility along with an accumulation of a 28kD protein in the walls of the growth-affected cells. A 3lkD protein that was 80% similar in amino acid sequence also was present but did not accumulate in the walls of the stem cells. In the stem, growth was inhibited and the mRNA for the 28kD protein increased in response to water deprivation but the mRNA for the 3 1 kD protein did not. The roots continued to grow and the mRNA for the 28kD protein did not accumulate but the mRNA for the 3lkD protein did. Thus, there was a tissuespecific response of gene expression that correlated with the contrasting growth response to low water potential in the same seedlings. Further work using immunogold labeling, fluorescence labeling, and western blotting gave evidence that the 28kD protein is located in the cell wall as well as several compartments in the cytoplasm. Preliminary experiments indicate that the 28kD protein is a phosphatase.

  19. Water use, productivity and interactions among desert plants. Final report

    SciTech Connect

    Ehleringer, J.R.

    1992-11-17

    Productivity, stability, and competitive interactions among ecosystem components within aridlands are key processes related directly to water in deserts. This project assumes that integrated aspects of plant metabolism provide insight into the structure and function of plant communities and ecosystems. While it is difficult to extrapolate from instantaneous physiological observations to higher scales, such as whole plant performance or to the interactions between plants as components of ecosystems, several key aspects of plant metabolism are scalable. Analyses of stable isotopic composition in plant tissues at natural abundance levels provide a useful tool that can provide insight into the consequences of physiological processes over temporal and spatial scales. Some plant processes continuously fractionate among light and heavy stable isotopic forms of an element; over time this results in integrated measures of plant metabolism. For example, carbon isotope fractionation during photosynthesis results in leaf carbon isotopic composition that is a measure of the set-point for photosynthetic metabolism and of water-use efficiency. Thus it provides information on the temporal scaling of a key physiological process.

  20. Water use, productivity and interactions among desert plants

    SciTech Connect

    Ehleringer, J.R.

    1992-11-17

    Productivity, stability, and competitive interactions among ecosystem components within aridlands are key processes related directly to water in deserts. This project assumes that integrated aspects of plant metabolism provide insight into the structure and function of plant communities and ecosystems. While it is difficult to extrapolate from instantaneous physiological observations to higher scales, such as whole plant performance or to the interactions between plants as components of ecosystems, several key aspects of plant metabolism are scalable. Analyses of stable isotopic composition in plant tissues at natural abundance levels provide a useful tool that can provide insight into the consequences of physiological processes over temporal and spatial scales. Some plant processes continuously fractionate among light and heavy stable isotopic forms of an element; over time this results in integrated measures of plant metabolism. For example, carbon isotope fractionation during photosynthesis results in leaf carbon isotopic composition that is a measure of the set-point for photosynthetic metabolism and of water-use efficiency. Thus it provides information on the temporal scaling of a key physiological process.

  1. Plant water uptake strategies to cope with stochastic rainfall

    NASA Astrophysics Data System (ADS)

    Tron, Stefania; Laio, Francesco; Ridolfi, Luca

    2013-03-01

    We develop and compare two hydraulically-based schemes of the xylem structure of an individual plant. The dynamics of water uptake are analyzed under random conditions through the modeling of rainfall as a stochastic process. The two hydraulic schemes differ in the modeling of the root ability to cooperate, i.e., the capacity of roots to increase the water uptake from the wetter soil layers when other parts of the soil are dry (compensation effect) and to transfer water from moister into drier soil layers (water redistribution effect). Both compensation and water redistribution are direct consequences of the hydraulic structure of the root system, which is modeled here considering two contrasting cases corresponding to non-interacting uptake paths from different soil layers, and converging uptake paths. Only the latter hydraulic architecture allows for compensation and water redistribution. Another important difference between the hydraulic schemes is the stomatal response to soil dryness. When the soil water is unevenly distributed in the soil layers, the differences in the hydraulic schemes emerge. In semi-arid climates, plants characterized by a cooperative root system are shown to be less prone to water stress. In contrast, plants with non-interacting roots result to be better fit to humid climates, where the probability of droughts is small.

  2. Foliar water uptake: a common water acquisition strategy for plants of the redwood forest.

    PubMed

    Limm, Emily Burns; Simonin, Kevin A; Bothman, Aron G; Dawson, Todd E

    2009-09-01

    Evaluations of plant water use in ecosystems around the world reveal a shared capacity by many different species to absorb rain, dew, or fog water directly into their leaves or plant crowns. This mode of water uptake provides an important water subsidy that relieves foliar water stress. Our study provides the first comparative evaluation of foliar uptake capacity among the dominant plant taxa from the coast redwood ecosystem of California where crown-wetting events by summertime fog frequently occur during an otherwise drought-prone season. Previous research demonstrated that the dominant overstory tree species, Sequoia sempervirens, takes up fog water by both its roots (via drip from the crown to the soil) and directly through its leaf surfaces. The present study adds to these early findings and shows that 80% of the dominant species from the redwood forest exhibit this foliar uptake water acquisition strategy. The plants studied include canopy trees, understory ferns, and shrubs. Our results also show that foliar uptake provides direct hydration to leaves, increasing leaf water content by 2-11%. In addition, 60% of redwood forest species investigated demonstrate nocturnal stomatal conductance to water vapor. Such findings indicate that even species unable to absorb water directly into their foliage may still receive indirect benefits from nocturnal leaf wetting through suppressed transpiration. For these species, leaf-wetting events enhance the efficacy of nighttime re-equilibration with available soil water and therefore also increase pre-dawn leaf water potentials. PMID:19585154

  3. Crop modeling: Studying the effect of water stress on the driving forces governing plant water potential

    NASA Astrophysics Data System (ADS)

    van Emmerik, T. H. M.; Mirfenderesgi, G.; Bohrer, G.; Steele-Dunne, S. C.; Van De Giesen, N.

    2015-12-01

    Water stress is one of the most important environmental factors that influence plant water dynamics. To prevent excessive water loss and physiological damage, plants can regulate transpiration by adjusting the stomatal aperture. This enhances survival, but also reduced photosynthesis and productivity. During periods of low water availability, stomatal regulation is a trade-off between optimization of either survival or production. Water stress defence mechanisms lead to significant changes in plant dynamics, e.g. leaf and stem water content. Recent research has shown that water content in a corn canopy can change up to 30% diurnally as a result of water stress, which has a considerable influence on radar backscatter from a corn canopy [1]. This highlighted the potential of water stress detection using radar. To fully explore the potential of water stress monitoring using radar, we need to understand the driving forces governing plant water potential. For this study, the recently developed the Finite-Element Tree-Crown Hydrodynamic model version 2 (FETCH2) model is applied to a corn canopy. FETCH2 is developed to resolve the hydrodynamic processes within a plant using the porous media analogy, allowing investigation of the influence of environmental stress factors on plant dynamics such as transpiration, photosynthesis, stomatal conductance, and leaf and stem water content. The model is parameterized and evaluated using a detailed dataset obtained during a three-month field experiment in Flevoland, the Netherlands, on a corn canopy. [1] van Emmerik, T., S. Steele-Dunne, J. Judge and N. van de Giesen: "Impact of Diurnal Variation in Vegetation Water Content on Radar Backscatter of Maize During Water Stress", Geosciences and Remote Sensing, IEEE Transactions on, vol. 52, issue 7, doi: 10.1109/TGRS.2014.2386142, 2015.

  4. Optimal plant water-use strategies under stochastic rainfall

    NASA Astrophysics Data System (ADS)

    Manzoni, Stefano; Vico, Giulia; Katul, Gabriel; Palmroth, Sari; Porporato, Amilcare

    2014-07-01

    Plant hydraulic traits have been conjectured to be coordinated, thereby providing plants with a balanced hydraulic system that protects them from cavitation while allowing an efficient transport of water necessary for photosynthesis. In particular, observations suggest correlations between the water potentials at which xylem cavitation impairs water movement and the one at stomatal closure, and between maximum xylem and stomatal conductances, begging the question as to whether such coordination emerges as an optimal water-use strategy under unpredictable rainfall. Here mean transpiration is used as a proxy for long-term plant fitness and its variations as a function of the water potentials at 50% loss of stem conductivity due to cavitation and at 90% stomatal closure are explored. It is shown that coordination between these hydraulic traits is necessary to maximize , with rainfall patterns altering the optimal range of trait values. In contrast, coordination between ecosystem-level conductances appears not necessary to maximize . The optimal trait ranges are wider under drier than under mesic conditions, suggesting that in semiarid systems different water use strategies may be equally successful. Comparison with observations across species from a range of ecosystems confirms model predictions, indicating that the coordinated functioning of plant organs might indeed emerge from an optimal response to rainfall variability.

  5. Spinodal Decomposition and Order-Disorder Transformation in a Water-Quenched U-6wt%Nb Alloy

    SciTech Connect

    Hsiung, L; Zhou, J

    2006-09-12

    A combinative approach of microhardness testing, tensile testing, and TEM microstructural analysis has been employed to study phase stability and aging mechanisms of a water-quenched U-6wt%Nb (WQU6Nb) alloy subjected to different aging schedules that include artificial aging of WQ-U6Nb at 200 C, natural aging of WQ-U6Nb at ambient temperatures for 15 to18 years, and accelerative aging of the naturally aged (NA) alloy at 200 C. During the early stages of artificial aging at 200 C, the microhardness values continuously increase as a result of the development of a fine-scale compositional modulation (wavelength: 3 nm) caused by spinodal decomposition. Coarsening of the modulated structure occurs after prolonged aging of WQ-U6Nb at 200 C for 16 hours, which leads to a decrease of microhardness. Phase instability has also been found to occur in the NA alloy, in which the formation of partially ordered phase domains resulting from an atomic-scale spinodal modulation (wavelength: 0.5 nm) renders the appearance of antiphase domain boundaries (APBs) in TEM images. Although 18-year natural aging does not cause a significant change in hardness, it affects dramatically the aging mechanism of WQ-U6Nb subjected to the accelerative aging at 200 C. The result of microhardness measurement shows that the hardness values continuously increase until after aging for 239 hours, and the total hardness increment is twice in magnitude than that in the case of the artificial aging of water-quenched alloy at 200 C. The anomalous increment of hardness for the accelerative aging of NA alloy can be attributed to the precipitation of an ordered U{sub 3}Nb phase. It is accordingly concluded that the long-term natural aging at ambient temperatures can detour the transformation pathway of WQ U-6Nb alloy; it leads to the order-disorder transformation and precipitation of ordered phase in the alloy.

  6. Macroscopic modeling of plant water uptake: soil and root resistances

    NASA Astrophysics Data System (ADS)

    Vogel, Tomas; Votrubova, Jana; Dohnal, Michal; Dusek, Jaromir

    2014-05-01

    The macroscopic physically-based plant root water uptake (RWU) model, based on water-potential-gradient formulation (Vogel et al., 2013), was used to simulate the observed soil-plant-atmosphere interactions at a forest site located in a temperate humid climate of central Europe and to gain an improved insight into the mutual interplay of RWU parameters that affects the soil water distribution in the root zone. In the applied RWU model, the uptake rates are directly proportional to the potential gradient and indirectly proportional to the local soil and root resistances to water flow. The RWU algorithm is implemented in a one-dimensional dual-continuum model of soil water flow based on Richards' equation. The RWU model is defined by four parameters (root length density distribution, average active root radius, radial root resistance, and the threshold value of the root xylem potential). In addition, soil resistance to water extraction by roots is related to soil hydraulic conductivity function and actual soil water content. The RWU model is capable of simulating both the compensatory root water uptake, in situations when reduced uptake from dry layers is compensated by increased uptake from wetter layers, and the root-mediated hydraulic redistribution of soil water, contributing to more natural soil moisture distribution throughout the root zone. The present study focusses on the sensitivity analysis of the combined soil water flow and RWU model responses in respect to variations of RWU model parameters. Vogel T., M. Dohnal, J. Dusek, J. Votrubova, and M. Tesar. 2013. Macroscopic modeling of plant water uptake in a forest stand involving root-mediated soil-water redistribution. Vadose Zone Journal, 12, 10.2136/vzj2012.0154.

  7. Animal or Plant: Which Is the Better Fog Water Collector?

    PubMed Central

    Nørgaard, Thomas; Ebner, Martin; Dacke, Marie

    2012-01-01

    Occasional fog is a critical water source utilised by plants and animals in the Namib Desert. Fog basking beetles (Onymacris unguicularis, Tenebrionidae) and Namib dune bushman grass (Stipagrostris sabulicola, Poaceae) collect water directly from the fog. While the beetles position themselves optimally for fog water collection on dune ridges, the grass occurs predominantly at the dune base where less fog water is available. Differences in the fog-water collecting abilities in animals and plants have never been addressed. Here we place beetles and grass side-by-side in a fog chamber and measure the amount of water they collect over time. Based on the accumulated amount of water over a two hour period, grass is the better fog collector. However, in contrast to the episodic cascading water run-off from the grass, the beetles obtain water in a steady flow from their elytra. This steady trickle from the beetles' elytra to their mouth could ensure that even short periods of fog basking – while exposed to predators – will yield water. Up to now there is no indication of specialised surface properties on the grass leafs, but the steady run-off from the beetles could point to specific property adaptations of their elytra surface. PMID:22509331

  8. Plant Response to Differential Soil Water Content and Salinity

    NASA Astrophysics Data System (ADS)

    Moradi, A. B.; Dara, A.; Kamai, T.; Ngo, A.; Walker, R.; Hopmans, J. W.

    2011-12-01

    Root-zone soil water content is extremely dynamic, governed by complex and coupled processes such as root uptake, irrigation, evaporation, and leaching. Root uptake of water and nutrients is influenced by these conditions and the processes involved. Plant roots are living and functioning in a dynamic environment that is subjected to extreme changes over relatively short time and small distances. In order to better manage our agricultural resources and cope with increasing constraints of water limitation, environmental concerns and climate change, it is vital to understand plants responses to these changes in their environment. We grew chick pea (Cicer arietinum) plants, in boxes of 30 x 25 x 1 cm dimensions filled with fine sand. Layers of coarse sand (1.5 cm thick) were embedded in the fine-sand media to divide the root growth environment into sections that were hydraulically disconnected from each other. This way, each section could be independently treated with differential levels of water and salinity. The root growth and distribution in the soil was monitored on daily bases using neutron radiography. Daily water uptake was measured by weighing the containers. Changes of soil water content in each section of the containers were calculated from the neutron radiographs. Plants that part of their root system was stressed with drought or salinity showed no change in their daily water uptake rate. The roots in the stressed sections stayed turgid during the stress period and looked healthy in the neutron images. However the uptake rate was severely affected when the soil in the non-stressed section started to dry. The plants were then fully irrigated with water and the water uptake rate recovered to its initial rate shortly after irrigation. The neutron radiographs clearly illustrated the shrinkage and recovery of the roots under stress and the subsequent relief. This cycle was repeated a few times and the same trend could be reproduced. Our results show that plants

  9. Drinkable rocks: plants can use crystallization water from gypsum

    NASA Astrophysics Data System (ADS)

    Palacio, Sara; Azorín, José; Montserrat-Martí, Gabriel; Ferrio, Juan Pedro

    2015-04-01

    Some minerals hold water in their crystalline structure. Such is the case of gypsum (CaSO4•2H2O), a rock forming mineral present in the arid and semi-arid regions of the five continents, including the dry most areas of the planet. Gypsum is also extensively found on Mars, where it constitutes a targeted substrate for the search of life. Under natural conditions and depending on the temperature, pressure, and dissolved electrolytes or organics, gypsum may lose crystallization water molecules, becoming bassanite (i.e. hemihydrate: CaSO4•½H2O) or anhydrite (CaSO4). As crystallization water can account for up to 20.8% of gypsum weight, it has been suggested that it could constitute a relevant source of water for organisms, particularly during summer. This suggestion is consistent with the phenology observed in some shallow-rooted plants growing on gypsum, which remain active when drought is intense, and with the increased soil moisture of gypsum soils during summer as compared to surrounding non-gypsum soils. Here we use the fact that the isotopic composition of free water differs from gypsum crystallization water to show that plants can use crystallization water from the gypsum structure. The composition of the xylem sap of gypsum plants during summer shows closer values to gypsum crystallization water than to free soil water. Crystallization water represents a significant water source for organisms growing on gypsum, especially during summer, when it accounts for 70-90% of the water used by shallow-rooted plants. These results significantly modify the current paradigm on water use by plants, where water held in the crystalline structure of mineral rocks is not regarded as a potential source. Given the existence of gypsum on the surface of Mars and its widespread occurrence on arid and semi-arid regions worldwide, our results have important implications for exobiology, the study of life under extreme conditions and arid land reclamation.

  10. Method and plant for storing fresh water

    SciTech Connect

    Dunkers, K.R.

    1988-04-05

    A tank for storage of a confined quantity of freshwater in a large body of saltwater is described comprising an upper annular support having flotation means so that the annular support can freely float in the body of salt water, vertically supported only by the flotation means; a non-expandable flexible skirt of sheet material extending downwardly from the annual support to define an open-bottomed storage tank; means on the skirt to maintain the skirt in a generally vertical downward orientation from the annual support while the support floats in the saltwater.

  11. The role of planted forests in urban water budgets (Invited)

    NASA Astrophysics Data System (ADS)

    McCarthy, H. R.; Pataki, D. E.; Litvak, E.

    2009-12-01

    In arid regions which are not naturally forested, urban trees are sustained through the redistribution of water resources as irrigation. Assessments of outdoor water use in Southwestern US cities have shown that not only is 30-75% of residential water use expended on outdoor landscapes, but that irrigation is frequently in excess of estimated plant demand. Thus, there is a need to understand the factors which influence the magnitude and variability of water use of urban trees. A complicating factor in assessing urban tree water use is the widely recognized heterogeneity of urban environments. Human choices and decision-making result in a landscape with significant variability in water and nutrient inputs, microclimate, biotic inputs and vegetation composition. In order to quantify urban tree water use and explain variation in water use resulting from variability in resource availability and species composition, we have conducted a combination of sapflux, growth and isotopic studies on more than 35 common (primarily non-native) tree species in the Los Angeles basin. The objective of these studies was to determine how much variability in water use and water use efficiency exists within and between commonly planted urban tree species, and what factors explain or can be used to predict this variability. Through these studies we have found considerable differences (up to two fold) in tree transpiration within a given species, attributable to differences in water and nutrient availability and tree planting density. Additionally, we have found substantial variation in the water use of different species: at typical urban planting densities, peak transpiration rates can be more than ten times greater for high transpiring trees than low transpiring trees. Finally, we found whole tree water use efficiency to vary across species by a factor of up to a hundred, explained to a large degree by the climate conditions (especially vapor pressure deficit) in the native ranges of

  12. Electrochemical continuous decomposition of chloroform and other volatile chlorinated hydrocarbons in water using a column type metal impregnated carbon fiber electrode

    SciTech Connect

    Sonoyama, Noriyuki; Sakata, Tadayoshi

    1999-10-01

    Trihalomethane and other chlorinated hydrocarbons are known to be toxic to human health. However, removal of these compounds from water is not easy. The authors attempted continuous electrochemical decomposition of chloroform that is the main compound of trihalomethanes and some toxic chlorinated hydrocarbons in water using a metal-impregnated CFE, concentration of chloroform in 0.5 M K{sub 2}SO{sub 4} (the supporting electrolyte) solution was decreased from 0.23m mol/L to below the limit of detection of their analysis system (1 ppm) at a flow rate of 1 mL/min. The main product of electrolysis was methane. This high efficiency, determined by the chemical yield, hardly changed at a flow rate of 20 mL/min at a Ag-impregnated CFE. At a flow rate of 1 mL/min, chloroform was degraded with a decomposition efficiency of almost 100% even in the solution without the supporting electrolyte, whereas at a higher flow rate, the efficiency for the decomposition of chloroform decreased with a decrease in the concentration of the supporting electrolyte. Tetrachloroethylene, 1,1,1-trichloroethane, and 1,1,2-trichloroethane were also decomposed at a Ag-impregnated CFE with an efficiency of almost 100%.

  13. Eichhornia azurea decomposition and the bacterial dynamic: an experimental research.

    PubMed

    Dahroug, Zaryf; Santana, Natália Fernanda; Pagioro, Thomaz Aurélio

    2016-01-01

    Organic decomposition is a complex interaction between chemical, physical and biological processes, where the variety of aquatic vascular plants is essential for the trophic dynamics of freshwater ecosystems. The goal of this study was to determine the aquatic macrophyte Eichhornia azurea (Sw.) Kunth decomposition rate, the time relation with the limnological parameters, and whether this relationship is a result of decomposition processes. To that end, we collected water and leaves of E. azurea in Surf Leopoldo, PR. The experiment consisted of two treatments: 25 containers with 450mL of water and 0.8g of biomass dry weight were used with or without the addition of macrophytes. Samples were collected in triplicate at times 0, 3h, 6h, 12h, 24h, 72h, 120h, 168h and 240h. When the container was removed, the plant material was dried in an oven. After 48h, the material was measured to obtain the final dry weight. Analyses of pH, conductivity, dissolved oxygen, total phosphorus N-ammonia (NH4), soluble reactive phosphorus (PO4) and dissolved organic carbon were performed, and the decomposition rate was calculated. The results showed significant temporal variation of limnological parameters in the study. Additionally, dissolved oxygen, conductivity, dissolved organic carbon and total phosphorus were correlated with the dry weight of the biomass, suggesting that E. azurea decomposition significantly interferes with the dynamics of these variables. PMID:26991303

  14. Do rock fragments participate to plant water and mineral nutrition?

    NASA Astrophysics Data System (ADS)

    Korboulewsky, Nathalie; Tétégan, Marion; Besnault, Adeline; Cousin, Isabelle

    2010-05-01

    Rock fragments modify soil properties, and can be a potential reservoir of water. Besides, recent studies showed that this coarse soil fraction is chemically active, release nutrients, and could therefore be involved in biogeochemical nutrient cycles. However, these studies carried out on rock fragments, crushed pebbles or mineral particles do not answer the question whether the coarse soil fraction has significant nutritive functions. Only a couple of studies were conducted on plants, one on grass and the other on coniferous seedlings. This present work attempted to assess if pebbles may act as water and nutrient sources for poplar saplings, a deciduous species. Remoulded soils were set up in 5 L-pots with three percentages of pebbles: 0, 20, and 40% in volume. We used, as substrate either fine earth or sand (quartz), and as rock fragments either calcareous or inert pebbles (quartz). Additional modalities were settled with sand mixed with 20 and 40% pebbles enriched with nutrients. Both fine earth and calcareous pebbles were collected from the Ap horizon of a calcareous lacustrine limestone silty soil located in the central region of France. After cleaning, all pebbles were mixed to reach a bulk density in pots of 1.1 g/cm3 for the fine earth and 1.5 g/cm3 for the sand. Ten replicates were settled per modality, and one cutting of Populus robusta was planted in each. The experiment was conducted under controlled conditions. All pots were saturated at the beginning of the experiment, then irrigated by capillarity and controlled to maintain a moderate water stress. Growth and evapotranspiration were followed regularly, while water stress status was measured by stomatal conductivity every day during two drying periods of 10 days. After three months, plants were collected, separated in below- and above-ground parts for biomass and cation analysis (Ca, Mg, K). Results showed that pebbles can participate to plant nutrition, but no reduction of water stress was observed

  15. Study of the dynamics of Zn, Fe, and Cu in the soil-plant system during leaf litter decomposition using isotopic compositions

    NASA Astrophysics Data System (ADS)

    Pichat, S.; Fekiacova, Z.

    2013-12-01

    Litter decomposition is a key process in the cycle of the elements in the soil-plant system. We have investigated the dynamics of three essential micronutrients (Zn, Fe, and Cu) in the vegetal cover, litter, organic horizons, and upper soil horizon (0-2 and 5-10 cm) using both element concentrations and isotopic compositions. The study was conducted on the O3HP (Oak Observatory at the Haute-Provence Observatory) experimental field site in southern France. O3HP is located far from pollution sources. It has been a fallow land for 70 years with the tree cover represented mainly by oak trees (Quercus pubescens). The soil is a thin layer of Calcisol developed under Mediterranean climate. The area has been subdivided in four zones as a function of plant cover. The results for two of these zones, dominated by respectively Poaceae and Genista hispanica, are reported here. We found that the concentrations of the three elements increase from the Ol to the Of horizon. Copper concentration in the Of horizon is close to that of the soil, whereas it is lower for Fe and Zn. For isotopic compositions, the behavior of the three elements is, however, different, which suggests different processes of redistribution for these elements. An enrichment in light Fe isotopes was observed from the Ol to the Of horizon, the latter having an isotopic composition similar to that of the soil. Zinc isotopic compositions are also similar in the Of horizon and the soil but they are isotopically heavier than in the Ol horizon. For Cu, the O horizons are isotopically heavier than the soil, with Of being the heaviest horizon. In addition, for Cu and Zn, the profiles in the O-horizons in the Poaceae-dominated and Genista hispanica-dominated areas are similar but their values are offset, suggesting an influence of the vegetal cover. The increase in concentration for Cu, Zn and Fe with age/depth in the O horizons is in agreement with what is commonly observed in litter-bag experiments, e.g. 1,2. Two

  16. Plant hydraulic traits govern forest water use and growth

    NASA Astrophysics Data System (ADS)

    Matheny, Ashley; Bohrer, Gil; Fiorella, Rich; Mirfenderesgi, Golnazalsadat

    2016-04-01

    Biophysical controls at the leaf, stem, and root levels govern plant water acquisition and use. Suites of sometimes co-varying traits afford plants the ability to manage water stress at each of these three levels. We studied the contrasting hydraulic strategies of red oaks (Q. rubra) and red maples (A. rubrum) in northern Michigan, USA. These two species differ in stomatal regulation strategy and xylem architecture, and are thought to root at different depths. Water use was monitored through sap flux, stem water storage, and leaf water potential measurements. Depth of water acquisition was determined on the basis of stable oxygen and hydrogen isotopes from xylem water samples taken from both species. Fifteen years of bole growth records were used to compare the influence of the trees' opposing hydraulic strategies on carbon acquisition and growth. During non-limiting soil moisture conditions, transpiration from red maples typically exceeded that of red oak. However, during a 20% soil dry down, transpiration from red maples decreased by more than 80%, while transpiration from red oaks only fell by 31%. Stem water storage in red maple also declined sharply, while storage in red oaks remained nearly constant. The more consistent isotopic compositions of xylem water samples indicated that oaks can draw upon a steady, deep supply of water which red maples cannot access. Additionally, red maple bole growth correlated strongly with mean annual soil moisture, while red oak bole growth did not. These results indicate that the deeper rooting strategy of red oaks allowed the species to continue transpiration and carbon uptake during periods of intense soil water limitation, when the shallow-rooted red maples ceased transpiration. The ability to root deeply could provide an additional buffer against drought-induced mortality, which may permit some anisohydric species, like red oak, to survive hydrologic conditions that would be expected to favor survival of more isohydric

  17. Woodland Decomposition.

    ERIC Educational Resources Information Center

    Napier, J.

    1988-01-01

    Outlines the role of the main organisms involved in woodland decomposition and discusses some of the variables affecting the rate of nutrient cycling. Suggests practical work that may be of value to high school students either as standard practice or long-term projects. (CW)

  18. Biogeochemistry of Decomposition and Detrital Processing

    NASA Astrophysics Data System (ADS)

    Sanderman, J.; Amundson, R.

    2003-12-01

    Decomposition is a key ecological process that roughly balances net primary production in terrestrial ecosystems and is an essential process in resupplying nutrients to the plant community. Decomposition consists of three concurrent processes: communition or fragmentation, leaching of water-soluble compounds, and microbial catabolism. Decomposition can also be viewed as a sequential process, what Eijsackers and Zehnder (1990) compare to a Russian matriochka doll. Soil macrofauna fragment and partially solubilize plant residues, facilitating establishment of a community of decomposer microorganisms. This decomposer community will gradually shift as the most easily degraded plant compounds are utilized and the more recalcitrant materials begin to accumulate. Given enough time and the proper environmental conditions, most naturally occurring compounds can completely be mineralized to inorganic forms. Simultaneously with mineralization, the process of humification acts to transform a fraction of the plant residues into stable soil organic matter (SOM) or humus. For reference, Schlesinger (1990) estimated that only ˜0.7% of detritus eventually becomes stabilized into humus.Decomposition plays a key role in the cycling of most plant macro- and micronutrients and in the formation of humus. Figure 1 places the roles of detrital processing and mineralization within the context of the biogeochemical cycling of essential plant nutrients. Chapin (1991) found that while the atmosphere supplied 4% and mineral weathering supplied no nitrogen and <1% of phosphorus, internal nutrient recycling is the source for >95% of all the nitrogen and phosphorus uptake by tundra species in Barrow, Alaska. In a cool temperate forest, nutrient recycling accounted for 93%, 89%, 88%, and 65% of total sources for nitrogen, phosphorus, potassium, and calcium, respectively ( Chapin, 1991). (13K)Figure 1. A decomposition-centric biogeochemical model of nutrient cycling. Although there is significant

  19. Mathematics for Water and Wastewater Treatment Plant Operators. Water and Wastewater Training Program.

    ERIC Educational Resources Information Center

    South Dakota Dept. of Environmental Protection, Pierre.

    This booklet is intended to aid the prospective waste treatment plant operator or drinking water plant operator in learning to solve mathematical problems, which is necessary for Class I certification. It deals with the basic mathematics which a Class I operator may require in accomplishing day-to-day tasks. The book also progresses into problems…

  20. STRATEGIES FOR WATER AND WASTE REDUCTION IN DAIRY FOOD PLANTS

    EPA Science Inventory

    A study was undertaken to reduce water and waste discharges in a complex, multiproduct dairy food plant through management control and modifications of equipment and processes. The objectives were to develop approaches that would be broadly applicable throughout the dairy industr...

  1. 7. VIEW OF WATER TREATMENT PLANT, ADJACENT TO THE COAL ...

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

    7. VIEW OF WATER TREATMENT PLANT, ADJACENT TO THE COAL CONVEYOR; IN THE DISTANCE IS THE FREQUENCY CHANGER HOUSE, WHICH IS ATTACHED TO SWITCH HOUSE NO. 1; LOOKING WEST. - Commonwealth Electric Company, Fisk Street Electrical Generating Station, 1111 West Cermak Avenue, Chicago, Cook County, IL

  2. Simulating Leaf Area of Corn Plants at Contrasting Water Status

    Technology Transfer Automated Retrieval System (TEKTRAN)

    An exponential decay function was fitted with literature data to describe the decrease in leaf expansion rate as leaf water potential decreases. The fitted function was then applied to modify an existing leaf area simulation module in a soil-plant-atmosphere continuum model in order to simulate leaf...

  3. Classroom Techniques to Illustrate Water Transport in Plants

    ERIC Educational Resources Information Center

    Lakrim, Mohamed

    2013-01-01

    The transport of water in plants is among the most difficult and challenging concepts to explain to students. It is even more difficult for students enrolled in an introductory general biology course. An easy approach is needed to demonstrate this complex concept. I describe visual and pedagogical examples that can be performed quickly and easily…

  4. PILOT PLANT PROJECT FOR REMOVING ORGANIC SUBSTANCES FROM DRINKING WATER

    EPA Science Inventory

    This report describes research on the European practice of preozonation of water to modify naturally occurring organics, followed by bacteria activated carbon (BAC) adsorption to remove trihalomethane precursors. A 100-gal/min pilot plant was designed, constructed and operated to...

  5. Fetal loss and work in a waste water treatment plant

    SciTech Connect

    Morgan, R.W.; Kheifets, L.; Obrinsky, D.L.; Whorton, M.D.; Foliart, D.E.

    1984-05-01

    We investigated pregnancy outcomes in 101 wives of workers employed in a waste water treatment plant (WWTP), and verified fetal losses by hospital records. Paternal work histories were compiled and each of the 210 pregnancies was assigned a paternal exposure category. The relative risk of fetal loss was increased when paternal exposure to the WWTP occurred around the time of conception.

  6. SEMIPERMEABLE MEMBRANE SYSTEM FOR SUBJECTING PLANTS TO WATER STRESS

    EPA Science Inventory

    A system was evaluated for growing plants at reproducible levels of water stress. Beans (Phaseolus vulgaris L.) were grown in vermiculite, transferred to a semipermeable membrane system that encased the root vermiculate mass, and then placed into nutrient solutions to which vario...

  7. Uptake of antibiotics from irrigation water by plants.

    PubMed

    Azanu, David; Mortey, Christiana; Darko, Godfred; Weisser, Johan Juhl; Styrishave, Bjarne; Abaidoo, Robert Clement

    2016-08-01

    The capacity of carrot (Daucus corota L.) and lettuce (Lactuca sativa L.), two plants that are usually eaten raw, to uptake tetracycline and amoxicillin (two commonly used antibiotics) from irrigated water was investigated in order to assess the indirect human exposure to antibiotics through consumption of uncooked vegetables. Antibiotics in potted plants that had been irrigated with known concentrations of the antibiotics were extracted using accelerated solvent extraction and analyzed on a liquid chromatograph-tandem mass spectrometer. The plants absorbed the antibiotics from water in all tested concentrations of 0.1-15 mg L(-1). Tetracycline was detected in all plant samples, at concentrations ranging from 4.4 to 28.3 ng/g in lettuce and 12.0-36.8 ng g(-1) fresh weight in carrots. Amoxicillin showed absorption with concentrations ranging from 13.7 ng g(-1) to 45.2 ng g(-1) for the plant samples. The mean concentration of amoxicillin (27.1 ng g(-1)) in all the samples was significantly higher (p = 0.04) than that of tetracycline (20.2 ng g(-1)) indicating higher uptake of amoxicillin than tetracycline. This suggests that the low antibiotic concentrations found in plants could be important for causing antibiotics resistance when these levels are consumed. PMID:27213239

  8. Ultrasonic Sensing of Plant Water Needs for Agriculture

    PubMed Central

    Gómez Álvarez-Arenas, Tomas; Gil-Pelegrin, Eustaquio; Ealo Cuello, Joao; Fariñas, Maria Dolores; Sancho-Knapik, Domingo; Collazos Burbano, David Alejandro; Peguero-Pina, Jose Javier

    2016-01-01

    Fresh water is a key natural resource for food production, sanitation and industrial uses and has a high environmental value. The largest water use worldwide (~70%) corresponds to irrigation in agriculture, where use of water is becoming essential to maintain productivity. Efficient irrigation control largely depends on having access to reliable information about the actual plant water needs. Therefore, fast, portable and non-invasive sensing techniques able to measure water requirements directly on the plant are essential to face the huge challenge posed by the extensive water use in agriculture, the increasing water shortage and the impact of climate change. Non-contact resonant ultrasonic spectroscopy (NC-RUS) in the frequency range 0.1–1.2 MHz has revealed as an efficient and powerful non-destructive, non-invasive and in vivo sensing technique for leaves of different plant species. In particular, NC-RUS allows determining surface mass, thickness and elastic modulus of the leaves. Hence, valuable information can be obtained about water content and turgor pressure. This work analyzes and reviews the main requirements for sensors, electronics, signal processing and data analysis in order to develop a fast, portable, robust and non-invasive NC-RUS system to monitor variations in leaves water content or turgor pressure. A sensing prototype is proposed, described and, as application example, used to study two different species: Vitis vinifera and Coffea arabica, whose leaves present thickness resonances in two different frequency bands (400–900 kHz and 200–400 kHz, respectively), These species are representative of two different climates and are related to two high-added value agricultural products where efficient irrigation management can be critical. Moreover, the technique can also be applied to other species and similar results can be obtained. PMID:27428968

  9. Ultrasonic Sensing of Plant Water Needs for Agriculture.

    PubMed

    Gómez Álvarez-Arenas, Tomas; Gil-Pelegrin, Eustaquio; Ealo Cuello, Joao; Fariñas, Maria Dolores; Sancho-Knapik, Domingo; Collazos Burbano, David Alejandro; Peguero-Pina, Jose Javier

    2016-01-01

    Fresh water is a key natural resource for food production, sanitation and industrial uses and has a high environmental value. The largest water use worldwide (~70%) corresponds to irrigation in agriculture, where use of water is becoming essential to maintain productivity. Efficient irrigation control largely depends on having access to reliable information about the actual plant water needs. Therefore, fast, portable and non-invasive sensing techniques able to measure water requirements directly on the plant are essential to face the huge challenge posed by the extensive water use in agriculture, the increasing water shortage and the impact of climate change. Non-contact resonant ultrasonic spectroscopy (NC-RUS) in the frequency range 0.1-1.2 MHz has revealed as an efficient and powerful non-destructive, non-invasive and in vivo sensing technique for leaves of different plant species. In particular, NC-RUS allows determining surface mass, thickness and elastic modulus of the leaves. Hence, valuable information can be obtained about water content and turgor pressure. This work analyzes and reviews the main requirements for sensors, electronics, signal processing and data analysis in order to develop a fast, portable, robust and non-invasive NC-RUS system to monitor variations in leaves water content or turgor pressure. A sensing prototype is proposed, described and, as application example, used to study two different species: Vitis vinifera and Coffea arabica, whose leaves present thickness resonances in two different frequency bands (400-900 kHz and 200-400 kHz, respectively), These species are representative of two different climates and are related to two high-added value agricultural products where efficient irrigation management can be critical. Moreover, the technique can also be applied to other species and similar results can be obtained. PMID:27428968

  10. An interpretation of some whole plant water transport phenomena.

    PubMed

    Fiscus, E L; Klute, A; Kaufmann, M R

    1983-04-01

    A treatment of water flow into and through plants to the evaporating surface of the leaves is presented. The model is driven by evaporation from the cell wall matrix of the leaves. The adsorptive and pressure components of the cell wall matric potential are analyzed and the continuity between the pressure component and the liquid tension in the xylem established. Continuity of these potential components allows linking of a root transport function, driven by the tension in the xylem, to the leaf water potential. The root component of the overall model allows for the solvent-solute interactions characteristic of a membrane-bound system and discussion of the interactions of environmental variables such as root temperature and soil water potentials. A partition function is developed from data in the literature which describes how water absorbed by the plant might be divided between transpiration and leaf growth over a range of leaf water potentials.Relationships between the overall system conductance and the conductance coefficients of the various plant parts (roots, xylem, leaf matrix) are established and the influence of each of these discussed.The whole plant flow model coupled to the partition function is used to simulate several possible relationships between leaf water potential and transpiration rate. The effects of changing some of the partition function coefficients, as well as the root medium water potential on these simulations is illustrated.In addition to the general usefulness of the model and its ability to describe a wide range of situations, we conclude that the relationships used, dealing with bulk fluid flow, diffusion, and solute transport, are adequate to describe the system and that analogically based theoretical systems, such as the Ohm's law analogy, probably ought to be abandoned for this purpose. PMID:16662912

  11. An Interpretation of Some Whole Plant Water Transport Phenomena

    PubMed Central

    Fiscus, Edwin L.; Klute, Arnold; Kaufmann, Merrill R.

    1983-01-01

    A treatment of water flow into and through plants to the evaporating surface of the leaves is presented. The model is driven by evaporation from the cell wall matrix of the leaves. The adsorptive and pressure components of the cell wall matric potential are analyzed and the continuity between the pressure component and the liquid tension in the xylem established. Continuity of these potential components allows linking of a root transport function, driven by the tension in the xylem, to the leaf water potential. The root component of the overall model allows for the solvent-solute interactions characteristic of a membrane-bound system and discussion of the interactions of environmental variables such as root temperature and soil water potentials. A partition function is developed from data in the literature which describes how water absorbed by the plant might be divided between transpiration and leaf growth over a range of leaf water potentials. Relationships between the overall system conductance and the conductance coefficients of the various plant parts (roots, xylem, leaf matrix) are established and the influence of each of these discussed. The whole plant flow model coupled to the partition function is used to simulate several possible relationships between leaf water potential and transpiration rate. The effects of changing some of the partition function coefficients, as well as the root medium water potential on these simulations is illustrated. In addition to the general usefulness of the model and its ability to describe a wide range of situations, we conclude that the relationships used, dealing with bulk fluid flow, diffusion, and solute transport, are adequate to describe the system and that analogically based theoretical systems, such as the Ohm's law analogy, probably ought to be abandoned for this purpose. PMID:16662912

  12. Soil management systems to improve water availability for plants

    NASA Astrophysics Data System (ADS)

    Klik, A.; Rosner, J.

    2009-04-01

    Due to climate change it is expected that the air temperature will increase and the amount as well as the variability of rainfall will change drastically within this century. Higher temperatures and fewer rainy days with more extreme events will increase the risk of surface runoff and erosion. This will lead to reduced soil water storage and therefore to a lower water use efficiency of plants. Soil and land management systems need to be applied and adapted to improve the amount of water stored in the soil and to ensure crop productivity functions of soils under changing climatic conditions. In a 14-yr. long field experiment, the effects of three soil management systems have been studied at three sites in Austria with respect to surface runoff, soil erosion, losses of nutrients and pesticides. Eight years after beginning of the project soil samples have been taken from different depth throughout the root zone to investigate the effects on soil properties. The results show that soil management systems with reduced tillage intensity are able to improve infiltration and soil water storage. More soil water enables plant development during longer dry periods and decreases amounts of irrigation. Overall, the higher water retention in the landscape improves the regional water balance and reduces environmental problems like soil erosion and nutrient and pesticide losses

  13. Biogeochemistry of Decomposition and Detrital Processing

    NASA Astrophysics Data System (ADS)

    Sanderman, J.; Amundson, R.

    2003-12-01

    Decomposition is a key ecological process that roughly balances net primary production in terrestrial ecosystems and is an essential process in resupplying nutrients to the plant community. Decomposition consists of three concurrent processes: communition or fragmentation, leaching of water-soluble compounds, and microbial catabolism. Decomposition can also be viewed as a sequential process, what Eijsackers and Zehnder (1990) compare to a Russian matriochka doll. Soil macrofauna fragment and partially solubilize plant residues, facilitating establishment of a community of decomposer microorganisms. This decomposer community will gradually shift as the most easily degraded plant compounds are utilized and the more recalcitrant materials begin to accumulate. Given enough time and the proper environmental conditions, most naturally occurring compounds can completely be mineralized to inorganic forms. Simultaneously with mineralization, the process of humification acts to transform a fraction of the plant residues into stable soil organic matter (SOM) or humus. For reference, Schlesinger (1990) estimated that only ˜0.7% of detritus eventually becomes stabilized into humus.Decomposition plays a key role in the cycling of most plant macro- and micronutrients and in the formation of humus. Figure 1 places the roles of detrital processing and mineralization within the context of the biogeochemical cycling of essential plant nutrients. Chapin (1991) found that while the atmosphere supplied 4% and mineral weathering supplied no nitrogen and <1% of phosphorus, internal nutrient recycling is the source for >95% of all the nitrogen and phosphorus uptake by tundra species in Barrow, Alaska. In a cool temperate forest, nutrient recycling accounted for 93%, 89%, 88%, and 65% of total sources for nitrogen, phosphorus, potassium, and calcium, respectively ( Chapin, 1991). (13K)Figure 1. A decomposition-centric biogeochemical model of nutrient cycling. Although there is significant

  14. Rates of Litter Decomposition and Soil Respiration in Relation to Soil Temperature and Water in Different-Aged Pinus massoniana Forests in the Three Gorges Reservoir Area, China

    PubMed Central

    Zeng, Lixiong; Huang, Zhilin; Lei, Jingpin; Zhou, Benzhi; Li, Maihe

    2014-01-01

    To better understand the soil carbon dynamics and cycling in terrestrial ecosystems in response to environmental changes, we studied soil respiration, litter decomposition, and their relations to soil temperature and soil water content for 18-months (Aug. 2010–Jan. 2012) in three different-aged Pinus massoniana forests in the Three Gorges Reservoir Area, China. Across the experimental period, the mean total soil respiration and litter respiration were 1.94 and 0.81, 2.00 and 0.60, 2.19 and 0.71 µmol CO2 m−2 s−1, and the litter dry mass remaining was 57.6%, 56.2% and 61.3% in the 20-, 30-, and 46-year-old forests, respectively. We found that the temporal variations of soil respiration and litter decomposition rates can be well explained by soil temperature at 5 cm depth. Both the total soil respiration and litter respiration were significantly positively correlated with the litter decomposition rates. The mean contribution of the litter respiration to the total soil respiration was 31.0%–45.9% for the three different-aged forests. The present study found that the total soil respiration was not significantly affected by forest age when P. masonniana stands exceed a certain age (e.g. >20 years old), but it increased significantly with increased soil temperature. Hence, forest management strategies need to protect the understory vegetation to limit soil warming, in order to reduce the CO2 emission under the currently rapid global warming. The contribution of litter decomposition to the total soil respiration varies across spatial and temporal scales. This indicates the need for separate consideration of soil and litter respiration when assessing the climate impacts on forest carbon cycling. PMID:25004164

  15. Water Extraction from Coal-Fired Power Plant Flue Gas

    SciTech Connect

    Bruce C. Folkedahl; Greg F. Weber; Michael E. Collings

    2006-06-30

    The overall objective of this program was to develop a liquid disiccant-based flue gas dehydration process technology to reduce water consumption in coal-fired power plants. The specific objective of the program was to generate sufficient subscale test data and conceptual commercial power plant evaluations to assess process feasibility and merits for commercialization. Currently, coal-fired power plants require access to water sources outside the power plant for several aspects of their operation in addition to steam cycle condensation and process cooling needs. At the present time, there is no practiced method of extracting the usually abundant water found in the power plant stack gas. This project demonstrated the feasibility and merits of a liquid desiccant-based process that can efficiently and economically remove water vapor from the flue gas of fossil fuel-fired power plants to be recycled for in-plant use or exported for clean water conservation. After an extensive literature review, a survey of the available physical and chemical property information on desiccants in conjunction with a weighting scheme developed for this application, three desiccants were selected and tested in a bench-scale system at the Energy and Environmental Research Center (EERC). System performance at the bench scale aided in determining which desiccant was best suited for further evaluation. The results of the bench-scale tests along with further review of the available property data for each of the desiccants resulted in the selection of calcium chloride as the desiccant for testing at the pilot-scale level. Two weeks of testing utilizing natural gas in Test Series I and coal in Test Series II for production of flue gas was conducted with the liquid desiccant dehumidification system (LDDS) designed and built for this study. In general, it was found that the LDDS operated well and could be placed in an automode in which the process would operate with no operator intervention or

  16. Synergistic integration of ion-exchange and catalytic reduction for complete decomposition of perchlorate in waste water.

    PubMed

    Kim, You-Na; Choi, Minkee

    2014-07-01

    Ion-exchange has been frequently used for the treatment of perchlorate (ClO4(-)), but disposal or regeneration of the spent resins has been the major hurdle for field application. Here we demonstrate a synergistic integration of ion-exchange and catalytic decomposition by using Pd-supported ion-exchange resin as an adsorption/catalysis bifunctional material. The ion-exchange capability of the resin did not change after generation of the Pd clusters via mild ethanol reduction, and thus showed very high ion-exchange selectivity and capacity toward ClO4(-). After the resin was saturated with ClO4(-) in an adsorption mode, it was possible to fully decompose the adsorbed ClO4(-) into nontoxic Cl(-) by the catalytic function of the Pd catalysts under H2 atmosphere. It was demonstrated that prewetting the ion-exchange resin with ethanol significantly accelerate the decomposition of ClO4(-) due to the weaker association of ClO4(-) with the ion-exchange sites of the resin, which allows more facile access of ClO4(-) to the catalytically active Pd-resin interface. In the presence of ethanol, >90% of the adsorbed ClO4(-) could be decomposed within 24 h at 10 bar H2 and 373 K. The ClO4(-) adsorption-catalytic decomposition cycle could be repeated up to five times without loss of ClO4(-) adsorption capacity and selectivity. PMID:24894447

  17. Water stress amelioration and plant growth promotion in wheat plants by osmotic stress tolerant bacteria.

    PubMed

    Chakraborty, U; Chakraborty, B N; Chakraborty, A P; Dey, P L

    2013-05-01

    Soil microorganisms with potential for alleviation of abiotic stresses in combination with plant growth promotion would be extremely useful tools in sustainable agriculture. To this end, the present study was initiated where forty-five salt tolerant bacterial isolates with ability to grow in high salt medium were obtained from the rhizosphere of Triticum aestivum and Imperata cylindrica. These bacteria were tested for plant-growth-promoting rhizobacteria traits in vitro such as phosphate solubilization, siderophore, ACC deaminase and IAA production. Of the forty-five isolates, W10 from wheat rhizosphere and IP8 from blady grass rhizosphere, which tested positive in all the tests were identified by morpholological, biochemical and 16SrDNA sequencing as Bacillus safensis and Ochrobactrum pseudogregnonense respectively and selected for in vivo studies. Both the bacteria could promote growth in six varieties of wheat tested in terms of increase in root and shoot biomass, height of plants, yield, as well as increase in chlorophyll content. Besides, the wheat plants could withstand water stress more efficiently in presence of the bacteria as indicated by delay in appearance of wilting symptoms increases in relative water content of treated water stressed plants in comparison to untreated stressed ones, and elevated antioxidant responses. Enhanced antioxidant responses were evident as elevated activities of enzymes such as catalase, peroxidase, ascorbate peroxidase, superoxide dismutase and glutathione reductase as well as increased accumulation of antioxidants such as carotenoids and ascorbate. Results clearly indicate that the ability of wheat plants to withstand water stress is enhanced by application of these bacteria which also function as plant growth promoting rhizobacteria. PMID:23239372

  18. Treating waste water from heat and electrical power plants and state regional power plants

    SciTech Connect

    Beigel`drud, G.M.

    1995-03-01

    Water is often contaminated with oil and other petroleum products when used by local and regional power plants. This article outlines the various methods of treating oil contaminated water and removing emulsions. Coagulation and flocculation are commonly used methods of treatment, but there are other means including flotation and electrochemical methods. Ammonium nitrite was used to accelerates the oil removal with an electrochemical method, which was chosen as the most efficient path towards removal.

  19. INNOVATIVE FRESH WATER PRODUCTION PROCESS FOR FOSSIL FUEL PLANTS

    SciTech Connect

    James F. Klausner; Renwei Mei; Yi Li; Mohamed Darwish; Diego Acevedo; Jessica Knight

    2003-09-01

    This report describes the annual progress made in the development and analysis of a Diffusion Driven Desalination (DDD) system, which is powered by the waste heat from low pressure condensing steam in power plants. The desalination is driven by water vapor saturating dry air flowing through a diffusion tower. Liquid water is condensed out of the air/vapor mixture in a direct contact condenser. A thermodynamic analysis demonstrates that the DDD process can yield a fresh water production efficiency of 4.5% based on a feed water inlet temperature of only 50 C. An example is discussed in which the DDD process utilizes waste heat from a 100 MW steam power plant to produce 1.51 million gallons of fresh water per day. The main focus of the initial development of the desalination process has been on the diffusion tower. A detailed mathematical model for the diffusion tower has been described, and its numerical implementation has been used to characterize its performance and provide guidance for design. The analysis has been used to design a laboratory scale diffusion tower, which has been thoroughly instrumented to allow detailed measurements of heat and mass transfer coefficient, as well as fresh water production efficiency. The experimental facility has been described in detail.

  20. Water, plants, and early human habitats in eastern Africa.

    PubMed

    Magill, Clayton R; Ashley, Gail M; Freeman, Katherine H

    2013-01-22

    Water and its influence on plants likely exerted strong adaptive pressures in human evolution. Understanding relationships among water, plants, and early humans is limited both by incomplete terrestrial records of environmental change and by indirect proxy data for water availability. Here we present a continuous record of stable hydrogen-isotope compositions (expressed as δD values) for lipid biomarkers preserved in lake sediments from an early Pleistocene archaeological site in eastern Africa--Olduvai Gorge. We convert sedimentary leaf- and algal-lipid δD values into estimates for ancient source-water δD values by accounting for biochemical, physiological, and environmental influences on isotopic fractionation via published water-lipid enrichment factors for living plants, algae, and recent sediments. Reconstructed precipitation and lake-water δD values, respectively, are consistent with modern isotopic hydrology and reveal that dramatic fluctuations in water availability accompanied ecosystem changes. Drier conditions, indicated by less negative δD values, occur in association with stable carbon-isotopic evidence for open, C(4)-dominated grassland ecosystems. Wetter conditions, indicated by lower δD values, are associated with expanded woody cover across the ancient landscape. Estimates for ancient precipitation amounts, based on reconstructed precipitation δD values, range between approximately 250 and 700 mm · y(-1) and are consistent with modern precipitation data for eastern Africa. We conclude that freshwater availability exerted a substantial influence on eastern African ecosystems and, by extension, was central to early human proliferation during periods of rapid climate change. PMID:23267102

  1. Wind increases "evaporative demand" but reduces plant water requirements

    NASA Astrophysics Data System (ADS)

    Schymanski, S. J.; Or, D.

    2015-12-01

    Transpiration is commonly conceptualised as a fraction of some potential rate, determined by stomatal or canopy resistance. Therefore, so-called "atmospheric evaporative demand" or "potential evaporation" is generally used alongside with precipitation and soil moisture to characterise the environmental conditions that affect plant water use. An increase in potential evaporation (e.g. due to climate change) is generally believed to cause increased transpiration and/or vegetation water stress, aggravating drought effects. In the present study, we investigated the question whether potential evaporation constitutes a meaningful reference for transpiration and compared sensitivity of potential evaporation and leaf transpiration to atmospheric forcing. Based on modelling results and supporting experimental evidence, we conclude that stomatal resistance cannot be parameterised as a factor relating transpiration to potential evaporation, as the ratio between transpiration and potential evaporation not only varies with stomatal resistance, but also with wind speed, air temperature, irradiance and relative humidity. Furthermore, the effect of wind speed in particular implies increase in potential evaporation, which is commonly interpreted as increased "water stress", but at the same time can reduce leaf transpiration, implying a decrease in water demand at the leaf scale. In fact, in a range of field measurements, we found that water use efficiency (WUE, carbon uptake per water transpired) commonly increases with increasing wind speed, enabling plants to conserve water during photosynthesis. We estimate that the observed global decrease in terrestrial near-surface wind speeds could have reduced WUE at a magnitude similar to the increase in WUE attributed to global rise in atmospheric carbon dioxide concentrations. We conclude that trends in wind speed and atmospheric carbon dioxide concentrations have to be considered explicitly for the estimation of drought effects on

  2. Simulated acid rain alters litter decomposition and enhances the allelopathic potential of the invasive plant Wedelia trilobata (Creeping Daisy)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Invasive species and acid rain cause global environmental problems. Limited information exists, however, concerning the effects of acid rain on the invasiveness of these plants. For example, creeping daisy, an invasive exotic allelopathic weed, has caused great damage in southern China where acid ra...

  3. Impacts of Soil Warming and Plant Rhizosphere on Root Litter Decomposition at Different Soil Depths in a Mediterranuan Grassland Lysimeter Facility

    NASA Astrophysics Data System (ADS)

    Zhu, B.; Hicks Pries, C.; Castanha, C.; Curtis, J. B.; Porras, R. C.; Torn, M. S.

    2014-12-01

    Accurate understanding of soil carbon cycling is critical for predicting climate-ecosystem feedbacks. Decomposition of root litter and its transformation into soil organic matter (SOM) are critical processes of soil carbon cycling. We aim to study the impacts of soil warming and plant rhizosphere on the fate of 13C-labeled roots buried at two soil depths using a field lysimeter facility at Hopland, California. The lysimeters contain soil columns of 38-cm diameter and 48-cm depth (0-15 cm A-horizon, and 15-48 cm B-horizon, Laughlin soil series) sown with annual grasses dominated by Avena barbata. The experiment has three treatments (planted-ambient, planted-warming (+4°C), and unplanted-ambient). In February 2014, 13C-labeled A. fatua roots were added to two depths (8-12 and 38-42 cm). We measured root-derived 13C in respired CO2 collected at the soil surface and in leachate dissolved organic carbon (DOC) collected from the lysimeters during the growing season and in soil harvested in August 2014. We found (1) soil temperature at two depths (10- and 40-cm) have been elevated by 4±0.2°C in the warmed compared to the ambient lysimeters; (2) surface (10-cm) volumetric soil moisture followed this order (unplanted-ambient > planted-ambient > planted-warming), while subsurface (40-cm) soil moisture showed little variation among treatments; (3) ecosystem respiration was enhanced by soil warming during the early growing season (March 15th and April 5th) when soil moisture was not limiting (>20%), while it was suppressed by soil warming during the late growing season (May 7th) when soil moisture was limiting (<20%), and was not significantly different among treatments towards the end of growing season (May 20th); and (4) aboveground plant biomass increased 25% with soil warming. More data including 13C values of ecosystem respiration, DOC loss, and harvested soil samples, as well as soil nutrient supply rates, microbial biomass and community structure will be presented

  4. Water Treatment Pilot Plant Design Manual: Low Flow Conventional/Direct Filtration Water Treatment Plant for Drinking Water Treatment Studies

    EPA Science Inventory

    This manual highlights the project constraints and concerns, and includes detailed design calculations and system schematics. The plant is based on engineering design principles and practices, previous pilot plant design experiences, and professional experiences and may serve as ...

  5. Optimization of the circulating water pumping system in power plants

    SciTech Connect

    Lapray, J.F.; Griffiths, I.L.; Chedru, P.J.

    1996-12-31

    The correct operation of power plants is dependent on the function of its major systems. The pumping station supplying cooling water is one such element. Cooling water systems in fossil fired and nuclear power plants are fed by pumps that must, without fail, run intensively. A shut down would automatically lead to a shut down of the plant unit it serves., e.g., a reduction of power output. The role of such pumps and the associated system is crucial and therefore cannot be compared with a drainage or irrigation pumping station that also handles large flows at low total head pressures. Operational reliability is of the utmost importance in the main circulating water systems. Pumping stations have increased in size following the turbine size rise. At one time a capacity of 130,000 USGPM was considered large, today`s requirements can be in the order of 2,600,000 USGPM. However, it is not just size that has increased, modern environmental considerations and economics require greater efficiency in all aspects, reductions in energy consumed, water usage, maintenance costs, etc. The once relatively simple principles that were taken into consideration in choice of equipment are no longer adaptable to the scale of current requirements. Optimization of not just the pumps but the complete integrated system as a whole must be paramount. This paper attempts to address the optimization of the complete system.

  6. Optimal Thermolysis Conditions for Soil Carbon Storage on Plant Residue Burning: Modeling the Trade-Off between Thermal Decomposition and Subsequent Biodegradation.

    PubMed

    Kajiura, Masako; Wagai, Rota; Hayashi, Kentaro

    2015-01-01

    Field burning of plant biomass is a widespread practice that provides charred materials to soils. Its impact on soil C sequestration remains unclear due to the heterogeneity of burning products and difficulty in monitoring the material's biodegradation in fields. Basic information is needed on the relationship between burning conditions and the resulting quantity/quality of residue-derived C altered by thermal decomposition and biodegradation. In this study, we thermolyzed residues (rice straw and husk) at different temperatures (200-600°C) under two oxygen availability conditions and measured thermal mass loss, C compositional change by solid-state C NMR spectroscopy, and biodegradability of the thermally altered residues by laboratory aerobic incubation. A trade-off existed between thermal and microbial decomposition: when burned at higher temperatures, residues experience a greater mass loss but become more recalcitrant via carbonization. When an empirical model accounting for the observed trade-off was projected over 10 to 10 yr, we identified the threshold temperature range (330-400°C) above and below which remaining residue C is strongly reduced. This temperature range corresponded to the major loss of O-alkyl C and increase in aromatic C. The O/C molar ratios of the resultant residues decreased to 0.2 to 0.4, comparable to those of chars in fire-prone field soils reported previously. Although the negative impacts of biomass burning need to be accounted for, the observed relationship may help to assess the long-term fate of burning-derived C and to enhance soil C sequestration. PMID:25602338

  7. Cost versus life cycle assessment-based environmental impact optimization of drinking water production plants.

    PubMed

    Capitanescu, F; Rege, S; Marvuglia, A; Benetto, E; Ahmadi, A; Gutiérrez, T Navarrete; Tiruta-Barna, L

    2016-07-15

    Empowering decision makers with cost-effective solutions for reducing industrial processes environmental burden, at both design and operation stages, is nowadays a major worldwide concern. The paper addresses this issue for the sector of drinking water production plants (DWPPs), seeking for optimal solutions trading-off operation cost and life cycle assessment (LCA)-based environmental impact while satisfying outlet water quality criteria. This leads to a challenging bi-objective constrained optimization problem, which relies on a computationally expensive intricate process-modelling simulator of the DWPP and has to be solved with limited computational budget. Since mathematical programming methods are unusable in this case, the paper examines the performances in tackling these challenges of six off-the-shelf state-of-the-art global meta-heuristic optimization algorithms, suitable for such simulation-based optimization, namely Strength Pareto Evolutionary Algorithm (SPEA2), Non-dominated Sorting Genetic Algorithm (NSGA-II), Indicator-based Evolutionary Algorithm (IBEA), Multi-Objective Evolutionary Algorithm based on Decomposition (MOEA/D), Differential Evolution (DE), and Particle Swarm Optimization (PSO). The results of optimization reveal that good reduction in both operating cost and environmental impact of the DWPP can be obtained. Furthermore, NSGA-II outperforms the other competing algorithms while MOEA/D and DE perform unexpectedly poorly. PMID:27107954

  8. Changes in water quality in the Owabi water treatment plant in Ghana

    NASA Astrophysics Data System (ADS)

    Akoto, Osei; Gyamfi, Opoku; Darko, Godfred; Barnes, Victor Rex

    2014-09-01

    The study was conducted on the status of the quality of water from the Owabi water treatment plant that supplies drinking water to Kumasi, a major city in Ghana, to ascertain the change in quality of water from source to point-of-use. Physico-chemical, bacteriological water quality parameters and trace metal concentration of water samples from five different treatment points from the Owabi water treatment plant were investigated. The raw water was moderately hard with high turbidity and colour that exceeds the WHO guideline limits. Nutrient concentrations were of the following order: NH3 < NO2 - < NO3 - < PO4 3- < SO4 2- and were all below WHO permissible level for drinking water in all the samples at different stages of treatment. Trace metal concentrations of the reservoir were all below WHO limit except chromium (0.06 mg/L) and copper (0.24 mg/L). The bacteriological study showed that the raw water had total coliform (1,766 cfu/100 mL) and faecal coliform (257 cfu/100 mL) that exceeded the WHO standard limits, rendering it unsafe for domestic purposes without treatment. Colour showed strong positive correlation with turbidity (r = 0.730), TSS (r ≥ 0.922) and alkalinity (0.564) significant at p < 0.01. The quality of the treated water indicates that colour, turbidity, Cr and Cu levels reduced and fall within the WHO permissible limit for drinking water. Treatment process at the water treatment plant is adjudged to be good.

  9. Water, plants, and early human habitats in eastern Africa

    PubMed Central

    Magill, Clayton R.; Ashley, Gail M.; Freeman, Katherine H.

    2013-01-01

    Water and its influence on plants likely exerted strong adaptive pressures in human evolution. Understanding relationships among water, plants, and early humans is limited both by incomplete terrestrial records of environmental change and by indirect proxy data for water availability. Here we present a continuous record of stable hydrogen-isotope compositions (expressed as δD values) for lipid biomarkers preserved in lake sediments from an early Pleistocene archaeological site in eastern Africa—Olduvai Gorge. We convert sedimentary leaf- and algal-lipid δD values into estimates for ancient source-water δD values by accounting for biochemical, physiological, and environmental influences on isotopic fractionation via published water–lipid enrichment factors for living plants, algae, and recent sediments. Reconstructed precipitation and lake-water δD values, respectively, are consistent with modern isotopic hydrology and reveal that dramatic fluctuations in water availability accompanied ecosystem changes. Drier conditions, indicated by less negative δD values, occur in association with stable carbon-isotopic evidence for open, C4-dominated grassland ecosystems. Wetter conditions, indicated by lower δD values, are associated with expanded woody cover across the ancient landscape. Estimates for ancient precipitation amounts, based on reconstructed precipitation δD values, range between approximately 250 and 700 mm·y−1 and are consistent with modern precipitation data for eastern Africa. We conclude that freshwater availability exerted a substantial influence on eastern African ecosystems and, by extension, was central to early human proliferation during periods of rapid climate change. PMID:23267102

  10. Significance of Plant Root Microorganisms in Reclaiming Water in CELSS

    NASA Technical Reports Server (NTRS)

    Bubenheim, David L.; Greene, Catherine; Wignarajah, Kanapathipillai; Kliss, Mark H. (Technical Monitor)

    1996-01-01

    Since many microorganisms demonstrate the ability to quickly break down complex mixtures of waste and environmental contaminants, examining their potential use for water recycling in a closed environment is appealing. Water contributes approximately 90 percent of the life sustaining provisions in a human space habitat. Nearly half of the daily water requirements will be used for personal hygiene and dish washing. The primary contaminants of the used "gray" water will be the cleansing agents or soaps used to carry out these functions. Reclaiming water from the gray water waste streams is one goal of the NASA program, Controlled Ecological Life Support Systems (CELSS). The microorganisms of plane roots are well documented to be of a beneficial effect to promote plant growth. Most plants exhibit a range of bacteria and fungi which can be highly plant-specific. In our investigations with lettuce grown in hydroponic culture, we identified a microflora of normal rhizosphere. When the roots were exposed to an anionic surfactant, the species diversity changed, based on morphological characteristics, with the numbers of species being reduced from 7 to 2 after 48 hours of exposure. In addition, the species that became dominant in the presence of the anionic surfactant also demonstrated a dramatic increase in population density which corresponded to the degradation of the surfactant in the root zone. The potential for using these or other rhizosphere bacteria as a primary or secondary waste processor is promising, but a number of issues still warrant investigation; these include but are not limited to: (1) the full identification of the microbes, (2) the classes of surfactants the microbes will degrade, (3) the environmental conditions required for optimal processing efficiency and (4) the ability of transferring the microbes to a non-living solid matrix such as a bioreactor.

  11. INNOVATIVE FRESH WATER PRODUCTION PROCESS FOR FOSSIL FUEL PLANTS

    SciTech Connect

    James F. Klausner; Renwei Mei; Yi Li; Jessica Knight

    2004-09-01

    An innovative Diffusion Driven Desalination (DDD) process was recently described where evaporation of mineralized water is driven by diffusion within a packed bed. The energy source to drive the process is derived from low pressure condensing steam within the main condenser of a steam power generating plant. Since waste heat is used to drive the process, the main cost of fresh water production is attributed to the energy cost of pumping air and water through the packed bed. This report describes the annual progress made in the development and analysis of a Diffusion Driven Desalination (DDD) system. A combined thermodynamic and dynamic analysis demonstrates that the DDD process can yield a fresh water production of 1.03 million gallon/day by utilizing waste heat from a 100 MW steam power plant based on a condensing steam pressure of only 3'' Hg. Throughout the past year, the main focus of the desalination process has been on the diffusion tower and direct contact condenser. Detailed heat and mass transfer analyses required to size and analyze these heat and mass transfer devices are described. An experimental DDD facility has been fabricated, and temperature and humidity data have been collected over a range of flow and thermal conditions. The analyses agree quite well with the current data and the information available in the literature. Direct contact condensers with and without packing have been investigated. It has been experimentally observed that the fresh water production rate is significantly enhanced when packing is added to the direct contact condensers.

  12. Modeling plant competition for soil water balance in Water-limited Mediterranean Ecosystems

    NASA Astrophysics Data System (ADS)

    Cortis, C.; Montaldo, N.

    2009-12-01

    In heterogeneous ecosystems, such Mediterranean ecosystems, contrasting plant functional types (PFTs, e.g., grass and woody vegetation) compete for the water use. In these complex ecosystems current modeling approaches need to be improved due to a general lack of knowledge about the relationship between ET and the plant survival strategies for the different PFTs under water stress. Indeed, still unsolved questions are: how the PFTs (in particular the root systems) compete for the water use, the impact of this competition on the water balance terms, and the role of the soil type and soil depth in this competition. For this reasons an elaborated coupled Vegetation dynamic model (VDM) - land surface model (LSM) model able to also predict root distribution of competing plant systems is developed. The transport of vertical water flow in the unsaturated soil is modelled through a Richards’ equation based model. The water extraction (sink) term is considered as the root water uptake. Two VDMs predict vegetation dynamics, including spatial and temporal distribution/evolution of the root systems in the soil of two competing species (grass and woody vegetation). An innovative method for solving the unlinear system of predicting equations is proposed. The coupled model is able to predict soil and root water potential of the two competing plant species. The model is tested for the Orroli case study, situated in the mid-west of Sardinia within the Flumendosa river watershed. The site landscape is a mixture of Mediterranean patchy vegetation types: trees, including wild olives and coark oaks, different shrubs and herbaceous species. In particular two contrasting plant functional types (grass and woody vegetation) have been included. The model well predict the soil moisture and vegetation dynamics for the case study, and significantly different root potentials are predicted for the two PFTs, highlighting the root competition for the water use. The soil depth is low in the case

  13. Modeling Halophytic Plants in APEX for Sustainable Water and Agriculture

    NASA Astrophysics Data System (ADS)

    DeRuyter, T.; Saito, L.; Nowak, B.; Rossi, C.; Toderich, K.

    2013-12-01

    A major problem for irrigated agricultural production is soil salinization, which can occur naturally or can be human-induced. Human-induced, or secondary salinization, is particularly a problem in arid and semi-arid regions, especially in irrigated areas. Irrigated land has more than twice the production of rainfed land, and accounts for about one third of the world's food, but nearly 20% of irrigated lands are salt-affected. Many farmers worldwide currently seasonally leach their land to reduce the soil salt content. These practices, however, create further problems such as a raised groundwater table, and salt, fertilizer, and pesticide pollution of nearby lakes and groundwater. In Uzbekistan, a combination of these management practices and a propensity to cultivate 'thirsty' crops such as cotton has also contributed to the Aral Sea shrinking nearly 90% by volume since the 1950s. Most common agricultural crops are glycophytes that have reduced yields when subjected to salt-stress. Some plants, however, are known as halophytic or 'salt-loving' plants and are capable of completing their life-cycle in higher saline soil or water environments. Halophytes may be useful for human consumption, livestock fodder, or biofuel, and may also be able to reduce or maintain salt levels in soil and water. To assess the potential for these halophytes to assist with salinity management, we are developing a model that is capable of tracking salinity under different management practices in agricultural environments. This model is interdisciplinary as it combines fields such as plant ecology, hydrology, and soil science. The US Department of Agriculture (USDA) model, Agricultural Policy/Environmental Extender (APEX), is being augmented with a salinity module that tracks salinity as separate ions across the soil-plant-water interface. The halophytes Atriplex nitens, Climacoptera lanata, and Salicornia europaea are being parameterized and added into the APEX model database. Field sites

  14. Warm water aquaculture using waste heat and water from zero discharge power plants in the Great Basin

    SciTech Connect

    Heckmann, R.A.; Winget, R.N.; Infanger, R.C.; Mickelsen, R.W.; Hendersen, J.M.

    1984-01-31

    Two series of experiments were completed to determine (a) toxicity of waste water from power plants on warm water fish and (b) multiple use of waste heat and water for aquatic animal and plant production. All three types of waste water from a typical coal-fired power plant are acceptable for growing catfish and tilapia following aeration. This growth was compared with fish raised in spring water. Closed, recirculating polyculture systems using evaporation pond water operated efficiently for plant (duckweed) and animal (fish and freshwater prawns) production. Duckweed is an excellent supplement for fish feed. Tilapia and freshwater prawns grew rapidly in the tanks containing duckweed only. 10 references, 13 tables.

  15. (Metabolic mechanisms of plant growth at low-water potentials)

    SciTech Connect

    Boyer, J.S.

    1989-01-01

    For the year 1989, the progress made on this DOE sponsored research will be described by considering the questions presented in the original proposal and describing the work on each one. We used soybean seedlings grown in vermiculite in a dark, humid environment because they are convenient to grow, undergo most of the physiological changes induced by low water potentials in large plants, and have exposed growing regions on which molecular experiments can be done.

  16. Foliar pathogenesis and plant water relations: a review.

    PubMed

    Grimmer, Michael K; John Foulkes, M; Paveley, Neil D

    2012-07-01

    As the world population grows, there is a pressing need to improve productivity from water use in irrigated and rain-fed agriculture. Foliar diseases have been reported to decrease crop water-use efficiency (WUE) substantially, yet the effects of plant pathogens are seldom considered when methods to improve WUE are debated. We review the effects of foliar pathogens on plant water relations and the consequences for WUE. The effects reported vary between host and pathogen species and between host genotypes. Some general patterns emerge however. Higher fungi and oomycetes cause physical disruption to the cuticle and stomata, and also cause impairment of stomatal closing in the dark. Higher fungi and viruses are associated with impairment of stomatal opening in the light. A number of toxins produced by bacteria and higher fungi have been identified that impair stomatal function. Deleterious effects are not limited to compatible plant-pathogen interactions. Resistant and non-host interactions have been shown to result in stomatal impairment in light and dark conditions. Mitigation of these effects through selection of favourable resistance responses could be an important breeding target in the future. The challenges for researchers are to understand how the effects reported from work under controlled conditions translate to crops in the field, and to elucidate underlying mechanisms. PMID:22664583

  17. Removal of fluoride contamination in water by three aquatic plants.

    PubMed

    Karmakar, Sukalpa; Mukherjee, Joydeep; Mukherjee, Somnath

    2016-01-01

    Phytoremediation, popularly known as 'green technology' has been employed in the present investigation to examine the potential of fluoride removal from water by some aquatic plants. Fluoride contamination in drinking water is very much prevalent in different parts of the world including India. Batch studies were conducted using some aquatic plants e.g., Pistia stratiotes, Eichhornia crassipes, and Spirodela polyrhiza which profusely grow in natural water bodies. The experimental data exhibited that all the above three aquatic floating macrophytes could remove fluoride to some relative degree of efficiency corresponding to initial concentration of fluoride 3, 5, 10, 20 mg/l after 10 days exposure time. Result showed that at lower concentration level i.e., 3 mg/L removal efficiency of Pistia stratiotes (19.87%) and Spirodela polyrhiza (19.23%) was found to be better as compared to Eichhornia crassipes (12.71%). Some of the physiological stress induced parameters such as chlorophyll a, chlorophyll b, total chlorophyll, carotenoid, total protein, catalase, and peroxidase were also studied to explore relative damage within the cell. A marginal stress was imparted among all the plants for lower concentration values (3 mg/L), whereas at 20 mg/l, maximum damage was observed. PMID:26247406

  18. Water balance measurements and simulations of maize plants on lysimeters

    NASA Astrophysics Data System (ADS)

    Heinlein, Florian; Biernath, Christian; Klein, Christian; Thieme, Christoph; Priesack, Eckart

    2016-04-01

    In Central Europe expected major aspects of climate change are a shift of precipitation events and amounts towards winter months, and the general increase of extreme weather events like heat waves or summer droughts. This will lead to strongly changing regional water availability and will have an impact on future crop growth, water use efficiency and yields. Therefore, to estimate future crop yields by growth models accurate descriptions of transpiration as part of the water balance is important. In this study, maize was grown on weighing lysimeters (sowdate: 24 April 2013). Transpiration was determined by sap flow measurement devices (ICT International Pty Ltd, Australia) using the Heat-Ratio-Method: two temperature probes, 0.5 cm above and below a heater, detect a heat pulse and its speed which allows the calculation of sap flow. Water balance simulations were executed with different applications of the model framework Expert-N. The same pedotransfer and hydraulic functions and the same modules to simulate soil water flow, soil heat and nitrogen transport, nitrification, denitrification and mineralization were used. Differences occur in the chosen potential evapotranspiration ETpot (Penman-Monteith ASCE, Penman-Monteith FAO, Haude) and plant modules (SPASS, CERES). In all simulations ETpot is separated into a soil and a plant part using the leaf are index (LAI). In a next step, these parts are reduced by soil water availability. The sum of these parts is the actual evapotranspiration ETact which is compared to the lysimeter measurements. The results were analyzed from Mid-August to Mid-September 2013. The measured sap flow rates show clear diurnal cycles except on rainy days. The SPASS model is able to simulate these diurnal cycles, overestimates the measurements on rainy days and at the beginning of the analyzed period, and underestimates transpiration on the other days. The main reason is an overestimation of potential transpiration Tpot due to too high

  19. Practical Application of Iterative Decomposition of Water and Fat with Echo Asymmetry and Least-Squares Estimation (IDEAL) Imaging in Minimizing Metallic Artifacts

    PubMed Central

    Hong, Hyun Sook; Park, Jai Soung; Paik, Sang Hyun; Lee, Hae Kyung

    2012-01-01

    Iterative decomposition of water and fat with echo asymmetry and the least-squares estimation (IDEAL) is a recently developed method for robust separation of fat and water with very high signal-to-noise-ratio (SNR) efficiency. In contrast to conventional fat-saturation methods, IDEAL is insensitive to magnetic field (B0 and B1) inhomogeneity. The aim of this study was to illustrate the practical application of the IDEAL technique in reducing metallic artifacts in postoperative patients with metallic hardware. The IDEAL technique can help musculoskeletal radiologists make an accurate diagnosis particularly in musculoskeletal imaging by reducing metallic artifacts, enabling the use of contrast enhancement, improving SNR performance, and providing various modes of MR images with one scan parameter. PMID:22563271

  20. Innovative Fresh Water Production Process for Fossil Fuel Plants

    SciTech Connect

    James F. Klausner; Renwei Mei; Yi Li; Jessica Knight; Venugopal Jogi

    2005-09-01

    This project concerns a diffusion driven desalination (DDD) process where warm water is evaporated into a low humidity air stream, and the vapor is condensed out to produce distilled water. Although the process has a low fresh water to feed water conversion efficiency, it has been demonstrated that this process can potentially produce low cost distilled water when driven by low grade waste heat. This report describes the annual progress made in the development and analysis of a Diffusion Driven Desalination (DDD) system. A dynamic analysis of heat and mass transfer demonstrates that the DDD process can yield a fresh water production of 1.03 million gallon/day by utilizing waste heat from a 100 MW steam power plant based on a condensing steam pressure of only 3 Hg. The optimum operating condition for the DDD process with a high temperature of 50 C and sink temperature of 25 C has an air mass flux of 1.5 kg/m{sup 2}-s, air to feed water mass flow ratio of 1 in the diffusion tower, and a fresh water to air mass flow ratio of 2 in the condenser. Operating at these conditions yields a fresh water production efficiency (m{sub fW}/m{sub L}) of 0.031 and electric energy consumption rate of 0.0023 kW-hr/kg{sub fW}. Throughout the past year, the main focus of the desalination process has been on the direct contact condenser. Detailed heat and mass transfer analyses required to size and analyze these heat and mass transfer devices are described. The analyses agree quite well with the current data. Recently, it has been recognized that the fresh water production efficiency can be significantly enhanced with air heating. This type of configuration is well suited for power plants utilizing air-cooled condensers. The experimental DDD facility has been modified with an air heating section, and temperature and humidity data have been collected over a range of flow and thermal conditions. It has been experimentally observed that the fresh water production rate is enhanced when air

  1. Mercury Bioaccumulation Potential from Wastewater Treatment Plants in Receiving Waters

    NASA Astrophysics Data System (ADS)

    Dean, J. D.; Mason, R. P.

    2008-12-01

    In early 2007, the Water Environment Research Foundation (WERF) mercury bioavailability project was initiated in response to the establishment of mercury Total Maximum Daily Load (TMDL) criteria around the country. While many TMDLs recognize that point sources typically constitute a small fraction of the mercury load to a water body, the question was raised concerning the relative bioavailablity of mercury coming from various sources. For instance, is the mercury discharged from a wastewater treatment plant more or less bioavailable than mercury contributed from other sources? This talk will focus on the results of a study investigating approaches to the estimation of bioavailability and potential bioaccumulation of mercury from wastewater treatment plants and other sources in receiving waters. From the outset, a working definition of bioavailability was developed which included not only methylmercury, the form that readily bioaccumulates in aquatic food chains, but also bioavailable inorganic mercury species that could be converted to methylmercury within a scientifically reasonable time frame. Factors that enhance or mitigate the transformation of inorganic mercury to methylmercury and its subsequent bioaccumulation were identified. Profiles were developed for various sources of mercury in watersheds, including wastewater treatment plants, with regard to methylmercury and inorganic bioavailable mercury, and the key factors that enhance or mitigate mercury bioavailability. Technologies that remove mercury from wastewater were reviewed and evaluated for their effect on bioavailability. A screening procedure was developed for making preliminary estimates of bioavailable mercury concentrations and fluxes in wastewater effluents and in fresh, estuarine and marine receiving waters. The procedure was validated using several diverse river and reservoir data sets. A "Bioavailability Tool" was developed which allows a user to estimate the bioavailability of an effluent and

  2. Foulant Characteristics Comparison in Recycling Cooling Water System Makeup by Municipal Reclaimed Water and Surface Water in Power Plant

    PubMed Central

    Ping, Xu; Jing, Wang; Yajun, Zhang; Jie, Wang; Shuai, Si

    2015-01-01

    Due to water shortage, municipal reclaimed water rather than surface water was replenished into recycling cooling water system in power plants in some cities in China. In order to understand the effects of the measure on carbon steel corrosion, characteristics of two kinds of foulant produced in different systems were studied in the paper. Differences between municipal reclaimed water and surface water were analyzed firstly. Then, the weight and the morphology of two kinds of foulant were compared. Moreover, other characteristics including the total number of bacteria, sulfate reducing bacteria, iron bacteria, extracellular polymeric substance (EPS), protein (PN), and polysaccharide (PS) in foulant were analyzed. Based on results, it could be concluded that microbial and corrosive risk would be increased when the system replenished by municipal reclaimed water instead of surface water. PMID:25893132

  3. Foulant characteristics comparison in recycling cooling water system makeup by municipal reclaimed water and surface water in power plant.

    PubMed

    Ping, Xu; Jing, Wang; Yajun, Zhang; Jie, Wang; Shuai, Si

    2015-01-01

    Due to water shortage, municipal reclaimed water rather than surface water was replenished into recycling cooling water system in power plants in some cities in China. In order to understand the effects of the measure on carbon steel corrosion, characteristics of two kinds of foulant produced in different systems were studied in the paper. Differences between municipal reclaimed water and surface water were analyzed firstly. Then, the weight and the morphology of two kinds of foulant were compared. Moreover, other characteristics including the total number of bacteria, sulfate reducing bacteria, iron bacteria, extracellular polymeric substance (EPS), protein (PN), and polysaccharide (PS) in foulant were analyzed. Based on results, it could be concluded that microbial and corrosive risk would be increased when the system replenished by municipal reclaimed water instead of surface water. PMID:25893132

  4. ARSENIC REMOVAL FROM DRINKING WATER BY COAGULATION/FILTRATION AND LIME SOFTENING PLANTS

    EPA Science Inventory

    This report documents a long term performance (one year) study of 3 water treatment plants to remove arsenic from drinking water sources. The 3 plants consisted of 2 conventional coagulation/filtration plants and 1 lime softening plant. The study involved the collecting of weekly...

  5. Biotic vs. abiotic control of decomposition: a comparison of the effects of simulated extinctions and changes in temperature.

    PubMed

    Boyero, Luz; Cardinale, Bradley J; Bastian, Mikis; Pearson, Richard G

    2014-01-01

    The loss of species is known to have significant effects on ecosystem functioning, but only recently has it been recognized that species loss might rival the effects of other forms of environmental change on ecosystem processes. There is a need for experimental studies that explicitly manipulate species richness and environmental factors concurrently to determine their relative impacts on key ecosystem processes such as plant litter decomposition. It is crucial to understand what factors affect the rate of plant litter decomposition and the relative magnitude of such effects because the rate at which plant litter is lost and transformed to other forms of organic and inorganic carbon determines the capacity for carbon storage in ecosystems and the rate at which greenhouse gasses such as carbon dioxide are outgassed. Here we compared how an increase in water temperature of 5°C and loss of detritivorous invertebrate and plant litter species affect decomposition rates in a laboratory experiment simulating stream conditions. Like some prior studies, we found that species identity, rather than species richness per se, is a key driver of decomposition, but additionally we showed that the loss of particular species can equal or exceed temperature change in its impact on decomposition. Our results indicate that the loss of particular species can be as important a driver of decomposition as substantial temperature change, but also that predicting the relative consequences of species loss and other forms of environmental change on decomposition requires knowledge of assemblages and their constituent species' ecology and ecophysiology. PMID:24466351

  6. Trade-Offs in Resource Allocation Among Moss Species Control Decomposition in Boreal Peatlands

    SciTech Connect

    Turetsky, M. R.; Crow, S. E.; Evans, R. J.; Vitt, D. H.; Wieder, R. K.

    2008-01-01

    We separated the effects of plant species controls on decomposition rates from environmental controls in northern peatlands using a full factorial, reciprocal transplant experiment of eight dominant bryophytes in four distinct peatland types in boreal Alberta, Canada. Standard fractionation techniques as well as compound-specific pyrolysis molecular beam mass spectrometry were used to identify a biochemical mechanism underlying any interspecific differences in decomposition rates. We found that over a 3-year field incubation, individual moss species and not micro-environmental conditions controlled early stages of decomposition. Across species, Sphagnum mosses exhibited a trade-off in resource partitioning into metabolic and structural carbohydrates, a pattern that served as a strong predictor of litter decomposition. Decomposition rates showed a negative co-variation between species and their microtopographic position, as species that live in hummocks decomposed slowly but hummock microhabitats themselves corresponded to rapid decomposition rates. By forming litter that degrades slowly, hummock mosses appear to promote the maintenance of macropore structure in surface peat hummocks that aid in water retention. Many northern regions are experiencing rapid climate warming that is expected to accelerate the decomposition of large soil carbon pools stored within peatlands. However, our results suggest that some common peatland moss species form tissue that resists decomposition across a range of peatland environments, suggesting that moss resource allocation could stabilize peatland carbon losses under a changing climate.

  7. Stable isotopes in leaf water of terrestrial plants.

    PubMed

    Cernusak, Lucas A; Barbour, Margaret M; Arndt, Stefan K; Cheesman, Alexander W; English, Nathan B; Feild, Taylor S; Helliker, Brent R; Holloway-Phillips, Meisha M; Holtum, Joseph A M; Kahmen, Ansgar; McInerney, Francesca A; Munksgaard, Niels C; Simonin, Kevin A; Song, Xin; Stuart-Williams, Hilary; West, Jason B; Farquhar, Graham D

    2016-05-01

    Leaf water contains naturally occurring stable isotopes of oxygen and hydrogen in abundances that vary spatially and temporally. When sufficiently understood, these can be harnessed for a wide range of applications. Here, we review the current state of knowledge of stable isotope enrichment of leaf water, and its relevance for isotopic signals incorporated into plant organic matter and atmospheric gases. Models describing evaporative enrichment of leaf water have become increasingly complex over time, reflecting enhanced spatial and temporal resolution. We recommend that practitioners choose a model with a level of complexity suited to their application, and provide guidance. At the same time, there exists some lingering uncertainty about the biophysical processes relevant to patterns of isotopic enrichment in leaf water. An important goal for future research is to link observed variations in isotopic composition to specific anatomical and physiological features of leaves that reflect differences in hydraulic design. New measurement techniques are developing rapidly, enabling determinations of both transpired and leaf water δ(18) O and δ(2) H to be made more easily and at higher temporal resolution than previously possible. We expect these technological advances to spur new developments in our understanding of patterns of stable isotope fractionation in leaf water. PMID:26715126

  8. Association of water spectral indices with plant and soil water relations in contrasting wheat genotypes

    PubMed Central

    Gutierrez, Mario; Reynolds, Matthew P.; Klatt, Arthur R.

    2010-01-01

    Spectral reflectance indices can be used to estimate the water status of plants in a rapid, non-destructive manner. Water spectral indices were measured on wheat under a range of water-deficit conditions in field-based yield trials to establish their relationship with water relations parameters as well as available volumetric soil water (AVSW) to indicate soil water extraction patterns. Three types of wheat germplasm were studied which showed a range of drought adaptation; near-isomorphic sister lines from an elite/elite cross, advanced breeding lines, and lines derived from interspecific hybridization with wild relatives (synthetic derivative lines). Five water spectral indices (one water index and four normalized water indices) based on near infrared wavelengths were determined under field conditions between the booting and grain-filling stages of crop development. Among all water spectral indices, one in particular, which was denominated as NWI-3, showed the most consistent associations with water relations parameters and demonstrated the strongest associations in all three germplasm sets. NWI-3 showed a strong linear relationship (r2 >0.6–0.8) with leaf water potential (ψleaf) across a broad range of values (–2.0 to –4.0 MPa) that were determined by natural variation in the environment associated with intra- and inter-seasonal affects. Association observed between NWI-3 and canopy temperature (CT) was consistent with the idea that genotypes with a better hydration status have a larger water flux (increased stomatal conductance) during the day. NWI-3 was also related to soil water potential (ψsoil) and AVSW, indicating that drought-adapted lines could extract more water from deeper soil profiles to maintain favourable water relations. NWI-3 was sufficiently sensitive to detect genotypic differences (indicated by phenotypic and genetic correlations) in water status at the canopy and soil levels indicating its potential application in precision phenotyping

  9. 78 FR 35330 - Initial Test Programs for Water-Cooled Nuclear Power Plants

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-06-12

    ... COMMISSION Initial Test Programs for Water-Cooled Nuclear Power Plants AGENCY: Nuclear Regulatory Commission... revision to Regulatory Guide (RG), 1.68, ``Initial Test Programs for Water-Cooled Nuclear Power Plants... Initial Test Programs (ITPs) for light water cooled nuclear power plants. ADDRESSES: Please refer...

  10. Soil Water Sensor Needs for the Evaluation of Hydraulic Lift in Crop Plants

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Hydraulic lift (HL) in plants is defined as the process by which water is redistributed from wet soil zones to drier soil zones through the plant root system in response to gradients in water potential. Water is released into the dry soil when plant transpiration is low (night) and reabsorbed by th...

  11. Organic halogens in unpolluted waters and large bodies of water receiving bleach plant effluents

    SciTech Connect

    Grimvall, A.; Jonsson, S.; Karlsson, S.; Savenhed, R.; Boren, H. )

    1991-05-01

    In this paper the authors review and update recently performed studies of organic halogens in unpolluted waters and two large bodies of water receiving bleach plant effluents---Lake Vattern in Sweden and the Baltic Sea. All water samples contained measurable amounts of adsorbable organic halogens (AOX); the highest concentrations (up to 200 {mu}g Cl/L) were observed in humic lakes not exposed to any industrial discharges. Analysis of chlorophenols revealed that there is a long-distance transport ({gt} 100 km) of chloroguaiacols from bleach plants to remote parts of receiving waters. However, there was no evidence of chlorinated organics from bleach plants accumulating over several years in the water phase. One chlorophenol, 2,4,6-trichlorophenol, and its methylated analogue, 2,4,6-trichloroanisole, were also detected in surface waters considered to be unpolluted. Mass balance calculations showed that different processes in terrestrial environments make large contributions of AOX; enzyme-mediated chlorination of humic substances is a plausible explanation to the widespread occurrence of organic halogens.

  12. Decomposition in northern Minnesota peatlands

    SciTech Connect

    Farrish, K.W.

    1985-01-01

    Decomposition in peatlands was investigated in northern Minnesota. Four sites, an ombrotrophic raised bog, an ombrotrophic perched bog and two groundwater minerotrophic fens, were studied. Decomposition rates of peat and paper were estimated using mass-loss techniques. Environmental and substrate factors that were most likely to be responsible for limiting decomposition were monitored. Laboratory incubation experiments complemented the field work. Mass-loss over one year in one of the bogs, ranged from 11 percent in the upper 10 cm of hummocks to 1 percent at 60 to 100 cm depth in hollows. Regression analysis of the data for that bog predicted no mass-loss below 87 cm. Decomposition estimates on an area basis were 2720 and 6460 km/ha yr for the two bogs; 17,000 and 5900 kg/ha yr for the two fens. Environmental factors found to limit decomposition in these peatlands were reducing/anaerobic conditions below the water table and cool peat temperatures. Substrate factors found to limit decomposition were low pH, high content of resistant organics such as lignin, and shortages of available N and K. Greater groundwater influence was found to favor decomposition through raising the pH and perhaps by introducing limited amounts of dissolved oxygen.

  13. Rhizosphere priming effect on soil organic carbon decomposition under plant species differing in soil acidification and root exudation.

    PubMed

    Wang, Xiaojuan; Tang, Caixian; Severi, Julia; Butterly, Clayton R; Baldock, Jeff A

    2016-08-01

    Effects of rhizosphere properties on the rhizosphere priming effect (RPE) are unknown. This study aimed to link species variation in RPE with plant traits and rhizosphere properties. Four C3 species (chickpea, Cicer arietinum; field pea, Pisum sativum; wheat, Triticum aestivum; and white lupin, Lupinus albus) differing in soil acidification and root exudation, were grown in a C4 soil. The CO2 released from soil was trapped using a newly developed NaOH-trapping system. White lupin and wheat showed greater positive RPEs, in contrast to the negative RPE produced by chickpea. The greatest RPE of white lupin was in line with its capacity to release root exudates, whereas the negative RPE of chickpea was attributed to its great ability to acidify rhizosphere soil. The enhanced RPE of field pea at maturity might result from high nitrogen deposition and release of structural root carbon components following root senescence. Root biomass and length played a minor role in the species variation in RPE. Rhizosphere acidification was shown to be an important factor affecting the magnitude and direction of RPE. Future studies on RPE modelling and mechanistic understanding of the processes that regulate RPE should consider the effect of rhizosphere pH. PMID:27101777

  14. Introduction to Chemistry for Water and Wastewater Treatment Plant Operators. Water and Wastewater Training Program.

    ERIC Educational Resources Information Center

    South Dakota Dept. of Environmental Protection, Pierre.

    Presented are basic concepts of chemistry necessary for operators who manage drinking water treatment plants and wastewater facilities. It includes discussions of chemical terms and concepts, laboratory procedures for basic analyses of interest to operators, and discussions of appropriate chemical calculations. Exercises are included and answer…

  15. Life Cycle Assesment of Daugavgriva Waste Water Treatment Plant

    NASA Astrophysics Data System (ADS)

    Romagnoli, F.; Sampaio, F.; Blumberga, D.

    2009-01-01

    This paper presents the assessment of the environmental impacts caused by the treatment of Riga's waste water in the Daugavgriva plant with biogas energy cogeneration through the life cycle assessment (LCA). The LCA seems to be a good tool to assess and evaluate the most serious environmental impacts of a facility The results showed clearly that the impact category contributing the most to the total impact -eutrophicationcomes from the wastewater treatment stage. Climate change also seems to be a relevant impact coming from the wastewater treatment stage and the main contributor to the Climate change is N2O. The main environmental benefits, in terms of the percentages of the total impact, associated to the use of biogas instead of any other fossil fuel in the cogeneration plant are equal to: 3,11% for abiotic depletation, 1,48% for climate change, 0,51% for acidification and 0,12% for eutrophication.

  16. (Metabolic mechanisms of plant growth at low water potentials)

    SciTech Connect

    Not Available

    1990-01-01

    The work supported by DOE showed that water-limitation inhibits plant growth first by imposing a physical limitation that is followed in a few h by metabolic changes leading to reduced wall extensibility in the enlarging cells. After the wall extensibility decreased, a 28kD protein accumulated particularly in the walls of the growth-affected cells. Antibodies were used to identify cDNA for the protein. The base sequence of the cDNA was typical of an enzyme rather than known structural components of walls. The sequence was identical to one published by another laboratory at the same time and encoding a protein that accumulates in vacuoles of depodded soybean plants.

  17. Soil water content and water supply of plants in the southern Crimea

    NASA Astrophysics Data System (ADS)

    Sudnitsyn, I. I.

    2008-01-01

    In cinnamonic soils of the Nikitsky Botanical Garden (Crimea), the average productive water reserves (WR) under different plants in 1981-1990 exhibited close correlation with the field water capacity (FC) and the productive moisture range, which is equal to the difference between the FC and the permanent wilting point (WP). The soil water content (SWC) regularly increased with the depth. An 8-year-long variation cycle of the meteorological conditions and the WR was revealed. A correlation between the WR and the precipitation was noted. The relationship of the occurrence frequencies of the FC and WR with their values was analogous to the Maxwell distribution close to the normal (Gaussian) distribution.

  18. 18 CFR 420.51 - Hydroelectric power plant water use charges.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 18 Conservation of Power and Water Resources 2 2012-04-01 2012-04-01 false Hydroelectric power plant water use charges. 420.51 Section 420.51 Conservation of Power and Water Resources DELAWARE RIVER... Use Charges § 420.51 Hydroelectric power plant water use charges. (a) Annual base charges. Owners...

  19. 18 CFR 420.51 - Hydroelectric power plant water use charges.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 18 Conservation of Power and Water Resources 2 2014-04-01 2014-04-01 false Hydroelectric power plant water use charges. 420.51 Section 420.51 Conservation of Power and Water Resources DELAWARE RIVER... Use Charges § 420.51 Hydroelectric power plant water use charges. (a) Annual base charges. Owners...

  20. The impact of water use fees on dispatching and water requirements for water-cooled power plants in Texas.

    PubMed

    Sanders, Kelly T; Blackhurst, Michael F; King, Carey W; Webber, Michael E

    2014-06-17

    We utilize a unit commitment and dispatch model to estimate how water use fees on power generators would affect dispatching and water requirements by the power sector in the Electric Reliability Council of Texas' (ERCOT) electric grid. Fees ranging from 10 to 1000 USD per acre-foot were separately applied to water withdrawals and consumption. Fees were chosen to be comparable in cost to a range of water supply projects proposed in the Texas Water Development Board's State Water Plan to meet demand through 2050. We found that these fees can reduce water withdrawals and consumption for cooling thermoelectric power plants in ERCOT by as much as 75% and 23%, respectively. To achieve these water savings, wholesale electricity generation costs might increase as much as 120% based on 2011 fuel costs and generation characteristics. We estimate that water saved through these fees is not as cost-effective as conventional long-term water supply projects. However, the electric grid offers short-term flexibility that conventional water supply projects do not. Furthermore, this manuscript discusses conditions under which the grid could be effective at "supplying" water, particularly during emergency drought conditions, by changing its operational conditions. PMID:24832169

  1. Rapid In Situ Identification of Source Water and Leaf Water in a Variety of Plant Species and Functional Types

    NASA Astrophysics Data System (ADS)

    Still, C. J.; Hu, J.; Berkelhammer, M. B.; Barnard, H. R.; Rahn, T.; Hsiao, G.; Raudzens Bailey, A.; Noone, D. C.

    2011-12-01

    Plant rooting distributions and use of soil water resources are important determinants of ecological and hydrological function. The isotope composition of plant xylem water can be used to infer soil water source variations, in particular differences among species and plant functional types. We report here on dynamics in the oxygen and hydrogen isotope composition of plant and soil water pools and fluxes within the Manitou Experimental Forest in the Colorado Rockies. For this work, we used multiple in situ laser-based spectroscopic analyzers to collect isotope data on soil water, leaf water, stem water, transpiration water, and canopy vapor from multiple heights in the canopy. Using an Induction Module - Cavity Ring-Down Spectroscopy system, which extracts and analyzes soil and plant samples in a few minutes, we measured soil and plant water isotopic composition from multiple soil depths and plant species at several points throughout the growing season. Stem (source) water isotopic composition varied greatly among the various plant species and functional types (pine trees, shrubs, forbs, grasses), broadly in agreement with expected plant rooting depths. The steady-state isotopic composition of leaf transpiration, another proxy of source water, was also consistent with this variation by plant functional type and rooting depth. Leaf water generally followed these patterns, but pine needles exhibited dramatic isotopic gradients along the needle length, with hydrogen isotope gradients of close to 100 per mil from leaf base to tip. We also introduced an isotopic label in two pines of different sizes (that were previously instrumented with sapflow probes and dendrometers) to further identify the pathways and pace of water flow though the trees. These results demonstrate the complex interactions between multiple source and fluxes of water, and that simple ecosystem isotope models, while generally valid, require careful evaluation as high-frequency and in situ isotopic data

  2. Has the plant genetic variability any role in models of water transfer in the soil-plant-atmosphere continuum ?

    NASA Astrophysics Data System (ADS)

    Tardieu, F.

    2012-04-01

    Water transfer in the SPAC is essentially linked to environmental conditions such as evaporative demand or soil water potential, and physical parameters such as soil hydraulic capacity or hydraulic conductivity. Models used in soil science most often represent the plant via a small number of variables such as the water flux that crosses the base of the stem or the root length (or area) in each soil layer. Because there is an increasing demand for computer simulations of plants that would perform better under water deficit, models of SPA water transfer are needed that could better take into account the genetic variability of traits involved in plant hydraulics. (i) The water flux through the plant is essentially limited by stomata, which present a much higher resistance to water flow than those in the soil - root continuum. This can lead to unexpected relations between flux, leaf water potential and root hydraulic conductance. (ii) A large genetic variability exists within and between species for stomatal control, with important consequences for the minimum soil water potential that is accessible to the plant. In particular, isohydric plants that maintain leaf water potential in a narrow range via stomatal control have a higher (nearer to 0) 'wilting point' than anisohydric plants that allow leaf water potential to reach very low values. (iii) The conductivity for water transfer in roots and shoots is controlled by plants via aquaporins. It largely varies with time of the day, water and nutrient status, in particular via plant hormones and circadian rhythms. Models of SPA water transfer with a time definition of minutes to hour should probably not ignore this, while those with longer time steps are probably less sensitive to changes in plant hydraulic conductivity. (iv) The "dogma" that dense root systems provide tolerance to water deficit is profoundly affected when the balance "H2O gain vs C investment" is taken into account. At least three programmes of recurrent

  3. A global experiment suggests climate warming will not accelerate litter decomposition in streams but might reduce carbon sequestration.

    PubMed

    Boyero, Luz; Pearson, Richard G; Gessner, Mark O; Barmuta, Leon A; Ferreira, Verónica; Graça, Manuel A S; Dudgeon, David; Boulton, Andrew J; Callisto, Marcos; Chauvet, Eric; Helson, Julie E; Bruder, Andreas; Albariño, Ricardo J; Yule, Catherine M; Arunachalam, Muthukumarasamy; Davies, Judy N; Figueroa, Ricardo; Flecker, Alexander S; Ramírez, Alonso; Death, Russell G; Iwata, Tomoya; Mathooko, Jude M; Mathuriau, Catherine; Gonçalves, José F; Moretti, Marcelo S; Jinggut, Tajang; Lamothe, Sylvain; M'Erimba, Charles; Ratnarajah, Lavenia; Schindler, Markus H; Castela, José; Buria, Leonardo M; Cornejo, Aydeé; Villanueva, Verónica D; West, Derek C

    2011-03-01

    The decomposition of plant litter is one of the most important ecosystem processes in the biosphere and is particularly sensitive to climate warming. Aquatic ecosystems are well suited to studying warming effects on decomposition because the otherwise confounding influence of moisture is constant. By using a latitudinal temperature gradient in an unprecedented global experiment in streams, we found that climate warming will likely hasten microbial litter decomposition and produce an equivalent decline in detritivore-mediated decomposition rates. As a result, overall decomposition rates should remain unchanged. Nevertheless, the process would be profoundly altered, because the shift in importance from detritivores to microbes in warm climates would likely increase CO(2) production and decrease the generation and sequestration of recalcitrant organic particles. In view of recent estimates showing that inland waters are a significant component of the global carbon cycle, this implies consequences for global biogeochemistry and a possible positive climate feedback. PMID:21299824

  4. Purification of fuel and nitrate contaminated ground water using a free water surface constructed wetland plant

    SciTech Connect

    Machate, T.; Heuermann, E.; Schramm, K.W.; Kettrup, A.

    1999-10-01

    Contaminated ground water from a former coke plant site was purified in a free water surface (FWS) constructed wetland plant during a 3-mo short-term experiment. The pilot plant (total surface area 27 m{sup 2}) was filled with a 1 m thick lava-gravel substrate planted with cattail (Typha spp.) and bulrush (Scirpus lacustrls). Major contaminants were low to moderate concentrations of polycyclic aromatic hydrocarbons, BTEX, nitrate, and nitrite. The wetland was dosed at hydraulic loading rates of q{sub A} = 4.8 and 9.6 cm d{sup {minus}1} with a hydraulic residence time (HRT) of 13.7 and 6.8 d. The surface removal rates of PAH were between 98.8 and 1914 mg m{sup {minus}2} d{sup {minus}1}. Efficiency was always {gt}99%. Extraction of lava gravel showed that approx. 0.4% of the applied PAH were retained on the substratum. The ratio of {Sigma}2,3-ring PAH and {Sigma}4,5,6-ring PAH showed a shift from 1:0.11 in water to 1:2.5 in lava. The removal of BTEX was {gt}99%, but might be in part due to volatilization. The efficiency in the removal of nitrate was 91% and of nitrite was 97%. Purification performance was not influenced by hydraulic loading rates or after die-back of the macrophytes.

  5. Estimating plant water uptake source depths with optimized stable water isotope labeling

    NASA Astrophysics Data System (ADS)

    Seeger, Stefan; Weiler, Markus

    2016-04-01

    Depth profiles of pore water stable isotopes in soils in conjunction with measurements of stable water isotopes (SWI) in plant transpiration allow the estimation of the contributions of different soil depths to plant water uptake (PWU).
 However, SWI depth profiles that result from the variations of SWI in natural precipitation may lead to highly ambiguous results, i.e. the same SWI signature in transpiration could result from different PWU patterns or SWI depth profiles. The aim of this study was to find an optimal stable water isotope depth profile to estimate plant water uptake patterns and to compare different PWU source depth estimation methods. We used a new soil water transport model including fractionation effects of SWI and exchange between the vapor and liquid phase to simulate different irrigation scenarios. Different amounts of water with differing SWI signatures (glacier melt water, summer precipitation water, deuterated water) were applied in order to obtain a wide variety of SWI depth profiles. Based on these simulated SWI depth profiles and a set of hypothetical PWU patterns, the theoretical SWI signatures of the respective plant transpiration were computed. In the next step, two methods - Bayesian isotope mixing models (BIMs) and optimization of a parametric distribution function (beta function) - were used to estimate the PWU patterns from the different SWI depth profiles and their respective SWI signatures in the resulting transpiration. Eventually, the estimated and computed profiles were compared to find the best SWI depth profile and the best method. The results showed, that compared to naturally occurring SWI depth profiles, the application of multiple, in terms of SWI, distinct labeling pulses greatly improves the possible spatial resolution and at the same time reduces the uncertainty of PWU estimates.
 For the PWU patterns which were assumed for this study, PWU pattern estimates based on an optimized parametric distribution function

  6. Examples of Savannah River water dilution between the Savannah River Plant and the Beaufort-Jasper and Port Wentworth water-treatment plants

    SciTech Connect

    Hayes, D.W.

    1983-01-12

    A substantial dilution of the river water occurs between the Savannah River Plant (SRP) and the two treatment plants. This dilution results from inflow of surface and groundwater and from direct rainfall. The amount of dilution was estimated to be approximately 20% and 54% down to the Port Wentworth and Beaufort-Jasper plants, respectively.

  7. Estimating plant available water content from remotely sensed evapotranspiration

    NASA Astrophysics Data System (ADS)

    van Dijk, A. I. J. M.; Warren, G.; Doody, T.

    2012-04-01

    Plant available water content (PAWC) is an emergent soil property that is a critical variable in hydrological modelling. PAWC determines the active soil water storage and, in water-limited environments, is the main cause of different ecohydrological behaviour between (deep-rooted) perennial vegetation and (shallow-rooted) seasonal vegetation. Conventionally, PAWC is estimated for a combination of soil and vegetation from three variables: maximum rooting depth and the volumetric water content at field capacity and permanent wilting point, respectively. Without elaborate local field observation, large uncertainties in PAWC occur due to the assumptions associated with each of the three variables. We developed an alternative, observation-based method to estimate PAWC from precipitation observations and CSIRO MODIS Reflectance-based Evapotranspiration (CMRSET) estimates. Processing steps include (1) removing residual systematic bias in the CMRSET estimates, (2) making spatially appropriate assumptions about local water inputs and surface runoff losses, (3) using mean seasonal patterns in precipitation and CMRSET to estimate the seasonal pattern in soil water storage changes, (4) from these, calculating the mean seasonal storage range, which can be treated as an estimate of PAWC. We evaluate the resulting PAWC estimates against those determined in field experiments for 180 sites across Australia. We show that the method produces better estimates of PAWC than conventional techniques. In addition, the method provides detailed information with full continental coverage at moderate resolution (250 m) scale. The resulting maps can be used to identify likely groundwater dependent ecosystems and to derive PAWC distributions for each combination of soil and vegetation type.

  8. Climate and ET: Does Plant Water Requirements Increase during Droughts?

    NASA Astrophysics Data System (ADS)

    Fipps, G.; Bonaiti, G.; Swanson, C.

    2012-04-01

    With the expected rise in global warming and increased frequency of extreme climate variability in the coming decades, conservation and efficient use of water resources is essential and must make use of the most accurate and representative data available. Historically, governmental and private organizations have used estimates of plant water use estimated from a variety of methods for long-term water planning, for designing hydraulic structures, and for establishing regulatory guidance and conservation programs intended to reduce water waste. In recent years, there has been an expansion of agricultural weather station networks which report daily ETo (potential evapotranspiration) and commercial irrigation controllers with instrumentation which calculate real-time ETo from weather parameters. Efforts are underway to use this more precise information for regional water planning and ETo is routinely used for designing and implementing drought response programs. The year 2011 marked the driest year on record in the State of Texas. Compounding the lack of rainfall was record heat during the summer of 2011. In 2011, real-time ETo (reference evapotranspiration) data in Texas was 30 to 50% higher than historic averages. The implications are quite serious, as most current water planning and drought contingency plans do not take into consideration increases in ET during such periods, and irrigation planning and capacity sizing are based on historic averages of consumptive use. This paper examines the relationship between ET and climate during this extreme climatic event. While the solar radiation was near normal levels, temperature and wind was much higher and dew points much lower than norms. The variability and statistical difference between long term average ETo and ETo measurements (from 2006 to 2011) for selected weather stations of the Texas ET Network.

  9. Numerical simulation of the thermal conditions in a sea bay water area used for water supply to nuclear power plants

    SciTech Connect

    Sokolov, A. S.

    2013-07-15

    Consideration is given to the numerical simulation of the thermal conditions in sea water areas used for both water supply to and dissipation of low-grade heat from a nuclear power plant on the shore of a sea bay.

  10. Phenol Decomposition Process by Pulsed-discharge Plasma above a Water Surface in Oxygen and Argon Atmosphere

    NASA Astrophysics Data System (ADS)

    Shiota, Haruki; Itabashi, Hideyuki; Satoh, Kohki; Itoh, Hidenori

    By-products from phenol by the exposure of pulsed-discharge plasma above a phenol aqueous solution are investigated by gas chromatography mass spectrometry, and the decomposition process of phenol is deduced. When Ar is used as a background gas, catechol, hydroquinone and 4-hydroxy-2-cyclohexene-1-on are produced, and no O3 is detected; therefore, active species such as OH, O, HO2, H2O2, which are produced from H2O in the discharge, can convert phenol into those by-products. When O2 is used as a background gas, formic acid, maleic acid, succinic acid and 4,6-dihydroxy-2,4-hexadienoic acid are produced in addition to catechol and hydroquinone. O3 is produced in the discharge plasma, so that phenol is probably decomposed into 4,6-dihydroxy-2,4-hexadienoic acid by 1,3-dipolar addition reaction with O3, and then 4,6-dihydroxy-2,4-hexadienoic acid can be decomposed into formic acid, maleic acid and succinic acid by 1,3-dipolar addition reaction with O3.

  11. Water treatment plant sludge disposal into stabilization ponds.

    PubMed

    Filho, Sidney Seckler Ferreira; Piveli, Roque Passos; Cutolo, Silvana Audrá; de Oliveira, Alexandre Alves

    2013-01-01

    Researchers have paid particular attention to the disposal of sludge produced in water treatment plants (WTPs) into wastewater treatment plants (WWTPs) for further processing, mainly because it is considered an attractive alternative for the treatment of waste generated in water production processes. This study evaluated the effects of flow equalization and disposal of sludge, from a conventional WTP, into a WWTP system that includes an anaerobic stabilization pond followed by a facultative pond. During the period of sludge discharge from the WTP into the wastewater system, the influent to the WWTP presented an increase of 17% (from 171 to 200 mg L(-1)) of total suspended solids (TSS) and a 7.0% flow rate increase, without showing adverse effects on the organic load, TSS and nutrients removal. The most significant impact observed in the WWTP was the increase of solids accumulation rate in the anaerobic pond, with a value of 141 mm/year during the sludge discharge period. The operating time, before the dredging and desludging cycles required for this specific anaerobic pond, decreased from 12.7 to 10.4 years, which is consistent with previous studies in literature. Thus, based on the observed parameters of this study, it is viable to release solids from a WTP effluent into a WWTP that includes anaerobic stabilization ponds followed by a facultative pond. Indeed, this process scheme becomes a viable technical, environmental, and economical alternative for small to medium WWTPs. PMID:23416593

  12. Effect of textile waste water on tomato plant, Lycopersicon esculentum.

    PubMed

    Marwari, Richa; Khan, T I

    2012-09-01

    In this study Sanganer town, Jaipur was selected as study area. The plants of Lycopersicon esculentum var. K 21(Tomato) treated with 20 and 30% textile wastewater were analyzed for metal accumulation, growth and biochemical parameters at per, peak and post flowering stages. Findings of the study revealed that chlorophyll content was most severely affected with the increase in metal concentration. Total chlorophyll content showed a reduction of 72.44% while carbohydrate, protein and nitrogen content showed a reduction of 46.83, 71.65 and 71.65% respectively. With the increase in waste water treatment the root and shoot length, root and shoot dry weight and total dry weight were reduced to 50.55, 52.06, 69.93, 72.42, 72.10% respectively. After crop harvesting, the fruit samples of the plants treated with highest concentration of textile waste water contained 2.570 mg g(-1)d.wt. of Zn, 0.800 mg g(-1) d.wt. Cu, 1.520 mg g(-1) d.wt. Cr and 2.010 mg g(-1) d.wt. Pb. PMID:23734449

  13. Influence of solar radiation and biotic interactions on bacterial and eukaryotic communities associated with sewage decomposition in ambient water

    EPA Science Inventory

    Sewage and ambient water both consist of a highly complex array of bacteria and eukaryotic microbes. When these communities are mixed, the persistence of sewage-derived pathogens in environmental waters can represent a significant public health concern. Solar radiation and biot...

  14. Influence of Solar Radiation and Biotic Interactions on Bacterial and Eukaryotic Communities Associated with Sewage Decomposition in Ambient Water - Poster

    EPA Science Inventory

    Sewage and ambient water both consist of a highly complex array of bacteria and eukaryotic microbes. When these communities are mixed, the persistence of sewage-derived pathogens in environmental waters can represent a significant public health concern. Solar radiation and biotic...

  15. Simulating Plant Water Stress and Phenology in Seasonally Dry Tropical Forests: Plant Hydraulics and Trait-Driven Trade-Offs

    NASA Astrophysics Data System (ADS)

    Xu, X.; Medvigy, D.; Powers, J. S.; Becknell, J. M.

    2014-12-01

    Seasonally dry tropical forests account for over 40% of the forested area in tropical and subtropical regions. Previous studies suggest that seasonal water stress is one main driver of phenology and related vegetation dynamics in seasonally dry tropical forests. Species that coexist in seasonally dry tropical forests have different plant traits, experience different degrees of plant water stress and show distinctive phenological patterns. However, the observed diversity in plant phenology and related vegetation dynamics is poorly represented in current dynamic vegetation models. In this study, we employ a new modeling approach to enhance our model skills in seasonally dry tropical forests. First, we implement a new plant hydraulic module under the framework of a state-of-the-art dynamic vegetation model, Ecosystem Demography 2 (ED2). Second, we link plant water stress with several key coordinated plant traits. Unlike previous models, the updated ED2 does not prescribe leaf phenology (deciduous or evergreen) and plant water stress is not determined by empirical water stress factors or by soil moisture alone. Instead, the model tracks more mechanistic indicators of plant water stress like leaf water potential, accounts for different abilities to tolerate water stress among plant functional types and predicts dry season leaf deciduousness and related vegetation dynamics. The updated model is then tested with in-situ meteorological data and long-term ecological observations. We also perform numerical experiments to explore the possible biases of ignoring the observed diversity in seasonally dry tropical forests. We find that (i) variations of several key plant traits (specific leaf area, wood density, turgor loss point and rooting depth) can account for the observed distinctive phenological patterns as well as inter-annual variations in vegetation growth among species. (ii) Ignoring the trait-driven trade-offs and diversity in seasonality would introduce significant

  16. Effects of livestock watering sites on alien and native plants in the Mojave Desert, USA

    USGS Publications Warehouse

    Brooks, M.L.; Matchett, J.R.; Berry, K.H.

    2006-01-01

    Increased livestock densities near artificial watering sites create disturbance gradients called piospheres. We studied responses of alien and native annual plants and native perennial plants within 9 piospheres in the Mojave Desert of North America. Absolute and proportional cover of alien annual plants increased with proximity to watering sites, whereas cover and species richness of native annual plants decreased. Not all alien species responded the same, as the alien forb Erodium cicutarium and the alien grass Schismus spp. increased with proximity to watering sites, and the alien annual grass Bromus madritensis ssp. rubens decreased. Perennial plant cover and species richness also declined with proximity to watering sites, as did the structural diversity of perennial plant cover classes. Significant effects were focused within 200 m of the watering sites, suggesting that control efforts for alien annual plants and restoration efforts for native plants should optimally be focused within this central part of the piosphere gradient.

  17. Origin and decomposition of sinking particulate organic matter in the deep water column inferred from the vertical distributions of its δ15N, δ13 and δ14

    NASA Astrophysics Data System (ADS)

    Nakatsuka, Takeshi; Handa, Nobuhiko; Harada, Naomi; Sugimoto, Tatsuhiro; Imaizumi, Shigemi

    1997-12-01

    Sinking particles were analyzed for their nitrogen isotopic ratio δ15N) of total particulate nitrogen (PN), stable carbon isotopic ratio ( δ13C) and radioactive isotopic ratio ( δ14C) of total particulate organic carbon (POC), at three different latitudinal (temperate, subpolar and equatorial) and geomorphological (trench, proximal abyssal plain and distal abyssal plain) sites in the western North Pacific Ocean using year-long time series sediment trap systems, to clarify the common vertical trends of the isotopic signals in deep water columns. Although the δ15N and δ13C values of sinking particulate organic matter (POM) were partly affected by the resuspension of sedimentary POM from the sea floor, especially in the trench, the changes in δ15N and δ13C values owing to the resuspension could be corrected by calculation of the isotopic mass balance from δ14C of sinking POC. After this correction, common downward decreasing trends in δ15N and δ13C values were obtained in the deep water columns, irrespective of the latitudes and depths. These coincidental isotopic signals between δ15N and δ13C values provide new constraints for the decomposition process of sinking POM, such as the preferential degradation of 15N- and 13C-rich compounds and the successive re-formation of the sinking particles by higher trophic level organisms in the deep water column.

  18. A partition-limited model for the plant uptake of organic contaminants from soil and water

    USGS Publications Warehouse

    Chiou, C.T.; Sheng, G.; Manes, M.

    2001-01-01

    In dealing with the passive transport of organic contaminants from soils to plants (including crops), a partition-limited model is proposed in which (i) the maximum (equilibrium) concentration of a contaminant in any location in the plant is determined by partition equilibrium with its concentration in the soil interstitial water, which in turn is determined essentially by the concentration in the soil organic matter (SOM) and (ii) the extent of approach to partition equilibrium, as measured by the ratio of the contaminant concentrations in plant water and soil interstitial water, ??pt (??? 1), depends on the transport rate of the contaminant in soil water into the plant and the volume of soil water solution that is required for the plant contaminant level to reach equilibrium with the external soil-water phase. Through reasonable estimates of plant organic-water compositions and of contaminant partition coefficients with various plant components, the model accounts for calculated values of ??pt in several published crop-contamination studies, including near-equilibrium values (i.e., ??pt ??? 1) for relatively water-soluble contaminants and lower values for much less soluble contaminants; the differences are attributed to the much higher partition coefficients of the less soluble compounds between plant lipids and plant water, which necessitates much larger volumes of the plant water transport for achieving the equilibrium capacities. The model analysis indicates that for plants with high water contents the plant-water phase acts as the major reservoir for highly water-soluble contaminants. By contrast, the lipid in a plant, even at small amounts, is usually the major reservoir for highly water-insoluble contaminants.

  19. Water and Plant Cells: Notes on a Teaching Scheme for O-Level.

    ERIC Educational Resources Information Center

    Grenville, H. W.

    1983-01-01

    Offers suggestions for teaching some aspects of water economy in plants. These include diffusion/osmosis, water transport, the part played by turgor in structural support, and its implications for plant organs or whole plants. Several practical demonstrations/experiments are also described. (JN)

  20. Small-scale Geothermal Power Plants Using Hot Spring Water

    NASA Astrophysics Data System (ADS)

    Tosha, T.; Osato, K.; Kiuchi, T.; Miida, H.; Okumura, T.; Nakashima, H.

    2013-12-01

    The installed capacity of the geothermal power plants has been summed up to be about 515MW in Japan. However, the electricity generated by the geothermal resources only contributes to 0.2% of the whole electricity supply. After the catastrophic earthquake and tsunami devastated the Pacific coast of north-eastern Japan on Friday, March 11, 2011, the Japanese government is encouraging the increase of the renewable energy supply including the geothermal. It needs, however, more than 10 years to construct the geothermal power plant with more than 10MW capacity since the commencement of the development. Adding the problem of the long lead time, high temperature fluid is mainly observed in the national parks and the high quality of the geothermal resources is limited. On the other hand hot springs are often found. The utilisation of the low temperature hot water becomes worthy of notice. The low temperature hot water is traditionally used for bathing and there are many hot springs in Japan. Some of the springs have enough temperature and enthalpy to turn the geothermal turbine but a new technology of the binary power generation makes the lower temp fluid to generate electricity. Large power generators with the binary technology are already installed in many geothermal fields in the world. In the recent days small-scale geothermal binary generators with several tens to hundreds kW capacity are developed, which are originally used by the waste heat energy in an iron factory and so on. The newly developed binary unit is compact suitable for the installation in a Japanese inn but there are the restrictions for the temperature of the hot water and the working fluid. The binary power unit using alternatives for chlorofluorocarbon as the working fluid is relatively free from the restriction. KOBELCO, a company of the Kobe Steel Group, designed and developed the binary power unit with an alternative for chlorofluorocarbon. The unit has a 70 MW class electric generator. Three

  1. Solar geoengineering, atmospheric water vapor transport, and land plants

    NASA Astrophysics Data System (ADS)

    Caldeira, Ken; Cao, Long

    2015-04-01

    This work, using the GeoMIP database supplemented by additional simulations, discusses how solar geoengineering, as projected by the climate models, affects temperature and the hydrological cycle, and how this in turn is related to projected changes in net primary productivity (NPP). Solar geoengineering simulations typically exhibit reduced precipitation. Solar geoengineering reduces precipitation because solar geoengineering reduces evaporation. Evaporation precedes precipitation, and, globally, evaporation equals precipitation. CO2 tends to reduce evaporation through two main mechanisms: (1) CO2 tends to stabilize the atmosphere especially over the ocean, leading to a moister atmospheric boundary layer over the ocean. This moistening of the boundary layer suppresses evaporation. (2) CO2 tends to diminish evapotranspiration, at least in most land-surface models, because higher atmospheric CO2 concentrations allow leaves to close their stomata and avoid water loss. In most high-CO2 simulations, these effects of CO2 which tend to suppress evaporation are masked by the tendency of CO2-warming effect to increase evaporation. In a geoengineering simulation, with the warming effect of CO2 largely offset by the solar geoengineering, the evaporation suppressing characteristics of CO2 are no longer masked and are clearly exhibited. Decreased precipitation in solar geoengineering simulations is a bit like ocean acidification - an effect of high CO2 concentrations that is not offset by solar geoengineering. Locally, precipitation ultimately either evaporates (much of that through the leaves of plants) or runs off through groundwater to streams and rivers. On long time scales, runoff equals precipitation minus evaporation, and thus, water runoff generated at a location is equal to the net atmospheric transport of water to that location. Runoff typically occurs where there is substantial soil moisture, at least seasonally. Locations where there is enough water to maintain

  2. Phase I: the pipeline-gas demonstration plant. Demonstration plant engineering and design. Volume 18. Plant Section 2700 - Waste Water Treatment

    SciTech Connect

    1981-05-01

    Contract No. EF-77-C-01-2542 between Conoco Inc. and the US Department of Energy provides for the design, construction, and operation of a demonstration plant capable of processing bituminous caking coals into clean pipeline quality gas. The project is currently in the design phase (Phase I). This phase is scheduled to be completed in June 1981. One of the major efforts of Phase I is the process and project engineering design of the Demonstration Plant. The design has been completed and is being reported in 24 volumes. This is Volume 18 which reports the design of Plant Section 2700 - Waste Water Treatment. The objective of the Waste Water Treatment system is to collect and treat all plant liquid effluent streams. The system is designed to permit recycle and reuse of the treated waste water. Plant Section 2700 is composed of primary, secondary, and tertiary waste water treatment methods plus an evaporation system which eliminates liquid discharge from the plant. The Waste Water Treatment Section is designed to produce 130 pounds per hour of sludge that is buried in a landfill on the plant site. The evaporated water is condensed and provides a portion of the make-up water to Plant Section 2400 - Cooling Water.

  3. The decomposition of the Faroe-Shetland Channel water masses using Parametric Optimum Multi-Parameter analysis

    NASA Astrophysics Data System (ADS)

    McKenna, C.; Berx, B.; Austin, W. E. N.

    2016-01-01

    The Faroe-Shetland Channel (FSC) is an important conduit for the poleward flow of Atlantic water towards the Nordic Seas and, as such, it plays an integral part in the Atlantic's thermohaline circulation. Mixing processes in the FSC are thought to result in an exchange of properties between the channel's inflow and outflow, with wider implications for this circulation; the nature of this mixing in the FSC is, however, uncertain. To constrain this uncertainty, we used a novel empirical method known as Parametric Optimum Multi-Parameter (POMP) analysis to objectively quantify the distribution of water masses in the channel in May 2013. This was achieved by using a combination of temperature and salinity measurements, as well as recently available nutrient and δ18O measurements. The outcomes of POMP analysis are in good agreement with established literature and demonstrate the benefits of representing all five water masses in the FSC. In particular, our results show the recirculation of Modified North Atlantic Water in the surface layers, and the pathways of Norwegian Sea Arctic Intermediate Water and Norwegian Sea Deep Water from north to south for the first time. In a final step, we apply the mixing fractions from POMP analysis to decompose the volume transport through the FSC by water mass. Despite a number of caveats, our study suggests that improved estimates of the volume transport of Atlantic inflow towards the Arctic and, thus, the associated poleward fluxes of salt and heat are possible. A new prospect to more accurately monitor the strength of the FSC branch of the thermohaline circulation emerges from this study.

  4. Mathematical modelling of plant water and nutrient uptake

    NASA Astrophysics Data System (ADS)

    Roose, Tiina

    2010-05-01

    In this presentation I will describe a model of plant water and nutrient uptake and how to translate this model and experimental data from the single root scale to the root branching structure scale. The model starts at the single root scale and describes the water and nutrient movement in the soil using Richards' equation (water uptake) and diffusion-convection equation (nutrient uptake). The water and nutrient uptake in the single root scale model is represented by boundary conditions. In the case of nutrient uptake this has the form of a non-linear Michaelis-Menten uptake law and in the case of water this is given by a soil-xylem pressure difference boundary condition. The flow of water in the xylem is modeled as Poiseuille flow. We solve the single root scale models using the analytic approximate technique of asymptotic expansions similar to Oseen expansions known from fluid dynamics. We will then discuss how to use the analytic expression to estimate the water and nutrient uptake by growing root branching systems. We model the growth of the root system using a dynamic population model to describe the branching and elongation of roots in the branching system. This root branching population model results in a hyperbolic equation similar to age dependent population models and it can be solved fully analytically using the method of characteristics. Thus we have a fully analytic description of the root branching system evolution. We use this branching model to estimate the nutrient uptake in a scenario when the competition between subbranches is small, i.e., as it is in the case of phosphate, potassium and arsenic. We compare our approximate analytic model to a full 3d simulation of the root system phosphate uptake and find that the analytic model almost perfectly reproduces the 3d numerical model. In addition the analytic model can be included in larger field/catchment/climate scale models something which is not practically possible with the numerical simulations

  5. Impact of drought on U.S. steam electric power plant cooling water intakes and related water resource management issues.

    SciTech Connect

    Kimmell, T. A.; Veil, J. A.; Environmental Science Division

    2009-04-03

    This report was funded by the U.S. Department of Energy's (DOE's) National Energy Technology Laboratory (NETL) Existing Plants Research Program, which has an energy-water research effort that focuses on water use at power plants. This study complements their overall research effort by evaluating water availability at power plants under drought conditions. While there are a number of competing demands on water uses, particularly during drought conditions, this report focuses solely on impacts to the U.S. steam electric power plant fleet. Included are both fossil-fuel and nuclear power plants. One plant examined also uses biomass as a fuel. The purpose of this project is to estimate the impact on generation capacity of a drop in water level at U.S. steam electric power plants due to climatic or other conditions. While, as indicated above, the temperature of the water can impact decisions to halt or curtail power plant operations, this report specifically examines impacts as a result of a drop in water levels below power plant submerged cooling water intakes. Impacts due to the combined effects of excessive temperatures of the returned cooling water and elevated temperatures of receiving waters (due to high ambient temperatures associated with drought) may be examined in a subsequent study. For this study, the sources of cooling water used by the U.S. steam electric power plant fleet were examined. This effort entailed development of a database of power plants and cooling water intake locations and depths for those plants that use surface water as a source of cooling water. Development of the database and its general characteristics are described in Chapter 2 of this report. Examination of the database gives an indication of how low water levels can drop before cooling water intakes cease to function. Water level drops are evaluated against a number of different power plant characteristics, such as the nature of the water source (river vs. lake or reservoir) and type

  6. Supercritical water oxidation of polyvinyl alcohol and desizing wastewater: influence of NaOH on the organic decomposition.

    PubMed

    Zhang, Jie; Wang, Shuzhong; Guo, Yang; Xu, Donghai; Gong, Yanmeng; Tang, Xingying

    2013-08-01

    Polyvinyl alcohol is a refractory compound widely used in industry. Here we report supercritical water oxidation of polyvinyl alcohol solution and desizing wastewater with and without sodium hydroxide addition. However, it is difficult to implement complete degradation of organics even though polyvinyl alcohol can readily crack under supercritical water treatment. Sodium hydroxide had a significant catalytic effect during the supercritical water oxidation of polyvinyl alcohol. It appears that the OH- ion participated in the C-C bond cleavage of polyvinyl alcohol molecules, the CO2-capture reaction and the neutralization of intermediate organic acids, promoting the overall reactions moving in the forward direction. Acetaldehyde was a typical intermediate product during reaction. For supercritical water oxidation of desizing wastewater, a high destruction rate (98.25%) based on total organic carbon was achieved. In addition, cases where initial wastewater was alkaline were favorable for supercritical water oxidation treatment, but salt precipitation and blockage issues arising during the process need to be taken into account seriously. PMID:24520696

  7. Plant response to environmental conditions: assessing potential production, water demand, and negative effects of water deficit

    PubMed Central

    Tardieu, François

    2013-01-01

    This paper reviews methods for analyzing plant performance and its genetic variability under a range of environmental conditions. Biomass accumulation is linked every day to available light in the photosynthetically active radiation (PAR) domain, multiplied by the proportion of light intercepted by plants and by the radiation use efficiency. Total biomass is cumulated over the duration of the considered phase (e.g., plant cycle or vegetative phase). These durations are essentially constant for a given genotype provided that time is corrected for temperature (thermal time). Several ways of expressing thermal time are reviewed. Two alternative equations are presented, based either on the effect of transpiration, or on yield components. Their comparative interests and drawbacks are discussed. The genetic variability of each term of considered equations affects yield under water deficit, via mechanisms at different scales of plant organization and time. The effect of any physiological mechanism on yield of stressed plants acts via one of these terms, although the link is not always straightforward. Finally, I propose practical ways to compare the productivity of genotypes in field environments, and a “minimum dataset” of environmental data and traits that should be recorded for that. PMID:23423357

  8. Turion morphological responses to water nutrient concentrations and plant density in the submerged macrophyte Potamogeton crispus

    PubMed Central

    Qian, Chang; You, Wenhua; Xie, Dong; Yu, Dan

    2014-01-01

    Asexual propagules are the dominant means of propagation in most submerged macrophytes. To improve the understanding of how water nutrient concentrations and population density influence the turion production of Potamogeton crispus L., the turions were planted in mesocosms with three water nutrient conditions (ambient lake water, high P and high N) and two plant density levels (4 and 15 turions m−2). After a 9-month experiment, the +P in the water column significantly increased the total turion number per plant under both of the plant density treatments. However, the +N in the water column did not affect the turion number per plant under low plant density. The +P in the water and high plant density significantly reduced the turion individual biomass. An examination of 3210 turion individuals from all treatments revealed that the increased water nutrient concentrations and plant density impacted the turion size by producing different stem diameters of individual turions. Most of the scale leaf morphological traits of the turions were significantly increased under higher water nutrients, but these traits were similar between the different plant density treatments. These results demonstrate that the water P concentration interacts with plant density, affecting both the production and traits of turions. PMID:25399866

  9. Water treatment plant site location using rough set theory.

    PubMed

    Arabani, M; Pirouz, M

    2015-10-01

    Currently, advanced methods have been developed to select an appropriate site for an engineering project. The ability to make a good decision in site selection can help the engineers to reduce the expensive costs, which are very important in large construction projects. In this paper, a new approach for site selection is presented. This method is based on rough set theory which is a mathematical theory presented by professor Pawlak. In this study, the results of the rough set decision-making are compared with the results of the regression method in a practical case study for the site location of a water treatment plant in Ardabil Province in the northwest of Iran, to demonstrate that the rough set theory provides a useful method for site selection. The results of practical studies indicate that using this method for site selection decision-making can reduce costs and prevent hazards that may happen due to civil engineering uncertainties. PMID:27613288

  10. TOXICITY TESTS OF EFFLUENTS WITH MARSH PLANTS IN WATER AND SEDIMENT

    EPA Science Inventory

    Methods are described for toxicity testing of water and sediment with the rooted marsh plants, Echinochloa crusgalli var. crusgalli and var. zelavensis (freshwater) and Spartina alterniflora (estuarine). ive industrial effluents, a sewage treatment plant effluent and a herbicide ...

  11. Rangeland - plant responses to elevated CO{sub 2}. Final report, October 1988--October 1993

    SciTech Connect

    1997-05-01

    Research is described on plant (tallgrass) response to elevated carbon dioxide. Variables addressed include biomass production, as well as water use efficiency, photosynthetic capacity, decomposition, nutrient cycling, and forage quality.

  12. Water quality investigation of Kingston Fossil Plant dry ash stacking

    SciTech Connect

    Bohac, C.E.

    1990-04-01

    Changing to a dry ash disposal systems at Kingston Fossil Plant (KFP) raises several water quality issues. The first is that removing the fly ash from the ash pond could alter the characteristics of the ash pond discharge to the river. The second concerns proper disposal of the runoff and possibly leachate from the dry ash stack. The third is that dry ash stacking might change the potential for groundwater contamination at the KFP. This report addresses each of these issues. The effects on the ash pond and its discharge are described first. The report is intended to provide reference material to TVA staff in preparation of environmental review documents for new ash disposal areas at Kingston. Although the investigation was directed toward analysis of dry stacking, considerations for other disposal options are also discussed. This report was reviewed in draft form under the title Assessment of Kingston Fossil Plant Dry Ash Stacking on the Ash Pond and Groundwater Quality.'' 11 refs., 3 figs., 18 tabs.

  13. 18 CFR 420.51 - Hydroelectric power plant water use charges.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 18 Conservation of Power and Water Resources 2 2013-04-01 2012-04-01 true Hydroelectric power plant water use charges. 420.51 Section 420.51 Conservation of Power and Water Resources DELAWARE RIVER BASIN COMMISSION ADMINISTRATIVE MANUAL BASIN REGULATIONS-WATER SUPPLY CHARGES Hydroelectric Power Water Use Charges § 420.51 Hydroelectric power...

  14. Spatial decomposition and assignment of infrared spectra of simple ions in water from mid-infrared to THz frequencies: Li+(aq) and F-(aq)

    NASA Astrophysics Data System (ADS)

    Śmiechowski, Maciej; Forbert, Harald; Marx, Dominik

    2013-07-01

    Ionic hydration is of fundamental relevance from chemical reactivity in aqueous solution to biomolecular function at physiological conditions. Vibrational spectroscopy belongs to the most widely used experimental methods in studies of solvation phenomena. There is, however, still limited molecular understanding as to how the vibrational response of solutions is modulated by the presence of solvation shells around solutes, i.e., by interfacial water. Liquid-state THz spectroscopy has been demonstrated to be able to detect even small solute-induced changes of the hydrogen bond dynamics at the solute-water interface. In many cases it reveals rather long-ranged dynamical correlations around solutes, involving many solvent molecules, that can be tackled theoretically by analyzing vibrational spectra in a distance-resolved manner. Here, several spatial decomposition schemes for infrared spectra are used to reveal the distinct distance- and frequency-dependent contributions of the solvation shells to the spectral response in aqueous solutions of Li+ and F-. The importance of an explicit representation of the solute's electronic structure for the proper description of solute-solvent polarization effects is demonstrated. The solvent's response to the presence of the solute is systematically disentangled and reveals important differences between the spectral responses due to intra- and intermolecular motion as probed in the mid- and far-infrared spectral windows, respectively.

  15. INVESTIGATIONS INTO THE GC/MS DECOMPOSITION OF TRIBROMONITROMETHANE IN DRINKING WATER DISINFECTION BY-PRODUCT ANALYSIS

    EPA Science Inventory

    Tribromonitromethane (bromopicrin) has been found to be a disinfection by-product (DBP) in
    chlorinated1 and ozonated2 drinking water, and is structurally similar to dibromonitromethane,
    which has been indicated through structural analysis to be a possible carcinogen. Bromop...

  16. Decomposition of saltmeadow cordgrass (Spartina patens) in Louisiana coastal marshes

    USGS Publications Warehouse

    Foote, A.L.; Reynolds, K.A.

    1997-01-01

    In Louisiana, plant production rates and associated decomposition rates may be important in offsetting high rates of land loss and subsidence in organic marsh soils. Decomposition of Spartina patens shoot and leaf material was studied by using litter bags in mesohaline marshes in the Barataria and Terrebonne basins of coastal Louisiana. Spartina patens decomposed very slowly with an average decay constant of 0.0007, and approximately 50% of the material remained after 2 years in the field. Material at the Barataria site decomposed faster than did Terrebonne material with trend differences apparent during the first 150 days. This difference might be explained by the higher content of phosphorus in the Barataria material or a flooding period experienced by the Barataria bags during their first 10 days of deployment. Nitrogen and carbon content of the plant material studied did not differ between the two basins. We detected no consistent significant differences in decomposition above, at, or below sediment/water level. Because S. patens is the dominant plant in these marshes, and because it is so slow to decompose, we believe that S. patens shoots are an important addition to vertical accretion and, therefore, marsh elevation.

  17. Detritus Quality Controls Macrophyte Decomposition under Different Nutrient Concentrations in a Eutrophic Shallow Lake, North China

    PubMed Central

    Li, Xia; Cui, Baoshan; Yang, Qichun; Tian, Hanqin; Lan, Yan; Wang, Tingting; Han, Zhen

    2012-01-01

    Macrophyte decomposition is important for carbon and nutrient cycling in lake ecosystems. Currently, little is known about how this process responds to detritus quality and water nutrient conditions in eutrophic shallow lakes in which incomplete decomposition of detritus accelerates the lake terrestrialization process. In this study, we investigated the effects of detritus quality and water nutrient concentrations on macrophyte decomposition in Lake Baiyangdian, China, by analyzing the decomposition of three major aquatic plants at three sites with different pollution intensities (low, medium, and high pollution sites). Detritus quality refers to detritus nutrient contents as well as C∶N, C∶P, and N∶P mass ratios in this study. Effects of detritus mixtures were tested by combining pairs of representative macrophytes at ratios of 75∶25, 50∶50 and 25∶75 (mass basis). The results indicate that the influence of species types on decomposition was stronger than that of site conditions. Correlation analysis showed that mass losses at the end of the experimental period were significantly controlled by initial detritus chemistry, especially by the initial phosphorus (P) content, carbon to nitrogen (C∶N), and carbon to phosphorus (C∶P) mass ratios in the detritus. The decomposition processes were also influenced by water chemistry. The NO3-N and NH4-N concentrations in the lake water retarded detritus mass loss at the low and high pollution sites, respectively. Net P mineralization in detritus was observed at all sites and detritus P release at the high pollution site was slower than at the other two sites. Nonadditive effects of mixtures tended to be species specific due to the different nutrient contents in each species. Results suggest that the nonadditive effects varied significantly among different sites, indicating that interactions between the detritus quality in species mixtures and site water chemistry may be another driver controlling decomposition

  18. Basic Study on Estimating Water Stress of a Plant Using Vibration Measurement of Leaf

    NASA Astrophysics Data System (ADS)

    Sano, Motoaki; Sugimoto, Tsuneyoshi; Hosoya, Hiroshi; Ohaba, Motoyoshi; Shibusawa, Sakae

    2013-07-01

    A new noninvasive method for estimating the water stress of a plant was proposed. In order to investigate this method, we first examined the characteristic frequency of an individual leaf picked from the plant, and obtained the result that its characteristic frequency decreased in proportion to the reduction in the water content of the leaf. Next, we applied this method to a leaf on a branch and confirmed the same tendency when the water stress was increased by stopping the water supply of a plant cultured in water. From these results, it was suggested that the water stress of the plant could be estimated from the vibration measurement of the leaf. Lastly, the relationship between the water potential of the leaf and its elastic constant was discussed with the soil-plant-atmosphere-continuum model (SPAC model), and Young's modulus of a tomato leaf was roughly estimated.

  19. Photocatalytic decomposition of water over platinum-intercalated K sub 4 Nb sub 6 O sub 17

    SciTech Connect

    Sayama, K.; Domen, K.; Maruya, K.; Onishi, T. ); Tanaka, A. )

    1991-02-07

    A Pt-intercalated K{sub 4}Nb{sub 6}O{sub 17} was prepared by ion exchange between (Pt(NH{sub 3}){sub 4}){sup 2+} and K{sup +} ions followed by H{sub 2} reduction. After aqua regia treatment for the removal of the platinum on the external surface of K{sub 4}Nb{sub 6}O{sub 17}, it showed an activity for photocatalytic overall water splitting without a reverse reaction.

  20. Belowground Water Dynamics Under Contrasting Annual and Perennial Plant Communities in an Agriculturally-Dominated Landscape

    NASA Astrophysics Data System (ADS)

    Mora, G.; Asbjornsen, H.; Helmers, M. J.; Shepherd, G. W.

    2005-12-01

    The conversion from grasslands and forests to row-crops in the Midwest has affected soil water cycling because plant characteristics are one of the main parameters determining soil storage capacity, infiltration rates, and surface runoff. Little is known, however, about the extent of modification of soil water dynamics under different plant communities. To address this important issue, we are documenting soil water dynamics under contrasting perennial and annual plant communities in an agriculturally-dominated landscape. Measurements of soil moisture and depths of uptake of source water were obtained for six vegetative cover types (corn and soybean field, brome pasture, degraded savanna, restored savanna, and restored prairie) at the Neal Smith National Wildlife Refuge in Prairie City, Iowa. The depths of uptake of soil water were determined on the basis of oxygen isotope composition of soil water and stem water. Measurements were performed once a month during an entire growing season. Preliminary results indicate that soil water present under the different vegetation types show similar profiles with depth during the dry months. Soil water in the upper 5 cm is enriched in oxygen-18 by about 5 per mil relative to soil water at 100 cm. Our preliminary results also indicate that the isotopic composition of stem water from annual plants is typically higher by about 2 per mil relative to that of stem water from perennial plants during the dry period. Whereas the oxygen isotopic composition for corn stem water is -5.49 per mil, that for elm and oak stem water is -7.62 and -7.51 per mil, respectively. The higher isotope values for corn suggest that annual crop plants are withdrawing water from shallower soil horizons relative to perennial plants. Moreover, our preliminary data suggest lower moisture content in soil under annual plant cover. We propose that the presence of deeper roots in the perennial vegetation allows these plants to tap into deeper water sources when

  1. Influence of Chemical Composition on the Reaction Products Observed During Electron Stimulated Decomposition of Organohalides Adsorbed in Water (Ice) Films

    NASA Astrophysics Data System (ADS)

    Fairbrother, Howard; Perry, Christopher; Faradzhev, Nadir; Madey, Theodore

    2004-03-01

    We report on the reactions of CF_2Cl2 and other organohalides codeposited_ in water (ice) films (≈100 nm thick on Au) at ˜ 100K during X-ray or electron beam irradiation. X-ray irradiation produces a distribution of low energy secondary electrons that in CF_2Cl_2/H_2O(ice) films produce H_3O^+, CO2 and COF2 (carbonyl fluoride). Chloride and fluoride anions are also produced and solvated (trapped) within the ice film during X-ray or electron irradiation. Product partitioning is dependent on the film's chemical composition; in water rich films, CO2 and COF2 production is favored, while a thermally stable partially halogenated CF_xCly film is detected in CF_2Cl2 rich films. During the early stages of irradiation, the dominance of Cl^- anions indicates that DEA of CF_2Cl2 via C-Cl cleavage (CF_2Cl2 + e^- → ot CF_2Cl + Cl^-) is the primary initial process. These results obtained for CF_2Cl2 are compared with electron stimulated reactions of other organohalides (CCl_4, CDCl_3, CD_2Cl2 and CH_3I) adsorbed in water(ice)films.

  2. Engineering the use of green plants to reduce produced water disposal volume.

    SciTech Connect

    Hinchman, R.; Mollock, G. N.; Negri, M. C.; Settle, T.

    1998-01-29

    In 1990, the Laboratory began an investigation into biological approaches for the reduction of water produced from oil and gas wells. In the spring of 1995, the Company began an on-site experiment at an oil/gas lease in Oklahoma using one of these approaches. The process, known as phytoremediation, utilizes the ability of certain salt tolerant plants to draw the produced water through their roots, transpire the water from their leaves, and thereby reduce overall water disposal volumes and costs. At the Company experimental site, produced water flows through a trough where green plants (primarily cordgrass) have been planted in pea gravel. The produced water is drawn into the plant through its roots, evapotranspirates and deposits a salt residue on the plant leaves. The plant leaves are then harvested and used by a local rancher as cattle feed. The produced water is tested to assure it contains nothing harmful to cattle. In 1996, the Company set up another trough to compare evaporation rates using plants versus using an open container without plants. Data taken during all four seasons (water flow rate, temperature, pH, and conductivity) have shown that using plants to evapotranspirate produced water is safe, more cost effective than traditional methods and is environmentally sound.

  3. Effects of climate change on water demand and water availability for power plants - examples for the German capital Berlin

    NASA Astrophysics Data System (ADS)

    Voegele, Stefan; Koch, Hagen; Grünewald, Uwe

    2010-05-01

    Effects of climate change on water demand and water availability for power plants - examples for the German capital Berlin Stefan Vögelea, Hagen Kochb&c, Uwe Grünewaldb a Forschungszentrum Jülich, Institute of Energy Research - Systems Analysis and Technology Evaluation, D-52425 Jülich, Germany b Brandenburg University of Technology Cottbus, Chair Hydrology and Water Resources Management, P.O. Box. 101 344, D-03013 Cottbus, Germany c Potsdam Institute for Climate Impact Research, Research Domain Climate Impacts and Vulnerabilities, P.O. Box 601203, D-14412 Potsdam, Germany Numerous power plants in Europe had to be throttled in the summer months of the years 2003 and 2006 due to water shortages and high water temperatures. Therefore, the effects of climate change on water availability and water temperature, and their effects on electric power generation in power plants have received much attention in the last years. The water demand of a power plant for cooling depends on the temperature of the surface waters from which the cooling water is withdrawn. Furthermore, air temperature and air humidity influence the water demand if a cooling tower is used. Beside climatic parameters, the demand for water depends on economic and technological factors as well as on the electricity demand and the socio-political framework. Since the different systems are connected with certain levels of uncertainty, scenarios of socio-economic development and climate change should be used in analyses of climate change on power plants and to identify adaptation measures. In this presentation the effects of global change, comprising technological, socio-economic and climate change, and adaptation options to water shortages for power plants in the German capital Berlin in the short- and long-term are analysed. The interconnection between power plants, i.e. water demand, and water resources management, i.e. water availability, is described in detail. By changing the cooling system of power

  4. Dioecy Impacts on Plant Water Fluxes in Riparian Ecosystems

    NASA Astrophysics Data System (ADS)

    Hultine, K. R.; Bush, S. E.; West, A. G.; Ehleringer, J. R.

    2005-12-01

    Dioecious plants are frequently associated with different spatial distributions of the two sexes across resource gradients. Segregation between sexes might be expected to occur if the cost of reproduction is greater in females than in males. If so, females would be under stronger selection to increase rates of resource uptake. Acer negundo is a dioecious riparian tree species that show spatial segregation among sexes: females are typically more common along streamside (high resource) environments than males. The spatial segregation of the sexes leads to the hypothesis that male and female individuals have varying influence on ecohydrological processes. To address this, we measured sap flux, water relations and hydraulic architecture of mature streamside (less than 1 m from stream channel) male and female Acer negundo trees occurring near Salt Lake City, Utah, USA during the 2004 growing season. Despite similar predawn and midday leaf water potentials, sap flux density ( Js) was 40 percent higher in female trees than in male trees during the 2004 growing season (n = 42 days, F = 73.56, P < 0.0001). Both genders showed a similar relationship between conducting sapwood area to stem diameter ratio suggesting that differences in Js scale to the whole tree level. Sap flux data from Acer negundo trees was compared to five other co-occurring riparian tree species. Female Acer negundo trees showed the highest Js among all species while Js in male Acer negundo trees was lower than all other species except one ( Acer grandidentatum). These data demonstrate that individual female Acer negundo trees have the capacity remove water at higher rates than males in high resource environments. The spatial segregation of the sexes along streamside environments may therefore have profound impacts on ecohydrological processes such as stream discharge, groundwater recharge, and nutrient cycling.

  5. Georgia-Pacific Palatka Plant Uses Thermal Pinch Analysis and Evaluates Water Reduction in Plant-Wide Energy Assessment

    SciTech Connect

    Not Available

    2002-12-01

    This OIT BestPractices Case Study describes the methods and results used in a plant-wide assessment at a Georgia-Pacific paper mill in Palatka, FL. Assessment personnel recommended several projects, which, if implemented, have the potential to save the plant more than 729,000 MMBtu per year and$2.9 million per year. In addition, the plant could reduce water use by 2,100 gallons per minute.

  6. Georgia-Pacific Palatka Plant Uses Thermal Pinch Analysis and Evaluates Water Reduction in Plant-Wide Energy Assessment

    SciTech Connect

    2002-12-01

    This OIT BestPractices Case Study describes the methods and results used in a plant-wide assessment at a Georgia-Pacific paper mill in Palatka, FL. Assessment personnel recommended several projects, which, if implemented, have the potential to save the plant more than 729,000 MMBtu per year and $2.9 million per year. In addition, the plant could reduce water use by 2,100 gallons per minute.

  7. Newly observed several peroxides from the gas phase ozonolysis of isoprene using a flow tube reactor and the water vapor effect on their formation and decomposition

    NASA Astrophysics Data System (ADS)

    Huang, D.; Chen, Z.; Zhao, Y.

    2012-12-01

    . Opposite to the previous conclusion that the peroxide yield would be positively correlated with RH, the yields of PAA and three unknown peroxides detected in the present study decreased with the RH increase. We tentatively assign these unknown peroxides to be hydroxyl hydroperoxides, which are produced by the reaction of different Criegee radicals with water. We used a box model coupled with the MCM v3.2 mechanism to simulate the reaction processes of the ozone-initiated oxidation of isoprene, adding the reaction between the gaseous water (and water dimer) and Criegee radicals and the decomposition of water-assisted hydroxyl hydroperoxides. We find that this modified mechanism would better explain the variation of peroxides with the RH increase, implying that molecular water and water cluster should be involved in the production and removal of peroxides in the future model.

  8. The functional role of carbonate-cemented soil horizons in desert ecosystems: Spatial and temporal dynamics of plant water availability

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In water limited ecosystems, soil profile characteristics can control plant community composition and production through their effects on spatial and temporal patterns of plant available water. Little is known, however, about water availability in soil horizons cemented with carbonates (petrocalcic ...

  9. Coupled Oxygen and Hydrogen Isotope Analysis of Water Along the Soil-Plant- Atmosphere Continuum

    NASA Astrophysics Data System (ADS)

    Huang, Z.; Webb, E. A.; Longstaffe, F. J.

    2008-12-01

    The oxygen and hydrogen isotope compositions of water within a plant vary with transpiration rates and the isotopic composition of soil water. Both of these parameters are affected by temperature and relative humidity. A controlled-temperature, growth-chamber experiment was conducted to determine the relationships among temperature, relative humidity, soil water evaporation and plant-water isotope composition in cattails and horsetails. Typha, a cattail species that grows in wetland conditions, and Equisetum, a horsetail species that prefers dry soils, were each grown in four chambers at 15, 20, 25 and 30 degrees Celsius. The oxygen and hydrogen isotope compositions of watering water, soil water, vapour in the growth chambers and plant water from the leaves and stems were analyzed throughout the eight-month long artificial growing season. Although the oxygen isotope composition of the watering water remained constant, the soil water, atmospheric vapour and plant water were progressively enriched in oxygen-18 and deuterium in each of the four chambers from low to high temperatures as a result of increasing evaporation. The oxygen isotope composition of plant water along the length of a single stem or leaf was increasingly enriched in the heavier isotopes towards the apex. There was no significant difference in the magnitude of this trend between species. These results indicate that the isotopic composition of plant water is primarily controlled by environmental conditions. The oxygen isotope composition of the water vapour in the growing chamber increased with temperature, consistent with equilibration between the vapour and the oxygen-18 enriched soil and plant water reservoirs. The magnitude and interaction of these variables, as measured for these modern samples of cattails and horsetails, should be useful in calibrating paleoclimate proxies based on fossilized plant materials (e.g., cellulose, phytoliths).

  10. Water relations in the interaction of foliar bacterial pathogens with plants.

    PubMed

    Beattie, Gwyn A

    2011-01-01

    This review examines the many ways in which water influences the relations between foliar bacterial pathogens and plants. As a limited resource in aerial plant tissues, water is subject to manipulation by both plants and pathogens. A model is emerging that suggests that plants actively promote localized desiccation at the infection site and thus restrict pathogen growth as one component of defense. Similarly, many foliar pathogens manipulate water relations as one component of pathogenesis. Nonvascular pathogens do this using effectors and other molecules to alter hormonal responses and enhance intercellular watersoaking, whereas vascular pathogens use many mechanisms to cause wilt. Because of water limitations on phyllosphere surfaces, bacterial colonists, including pathogens, benefit from the protective effects of cellular aggregation, synthesis of hygroscopic polymers, and uptake and production of osmoprotective compounds. Moreover, these bacteria employ tactics for scavenging and distributing water to overcome water-driven barriers to nutrient acquisition, movement, and signal exchange on plant surfaces. PMID:21438680

  11. Kinetic and equilibrium study on formic acid decomposition in relation to the water-gas-shift reaction.

    PubMed

    Yasaka, Yoshiro; Yoshida, Ken; Wakai, Chihiro; Matubayasi, Nobuyuki; Nakahara, Masaru

    2006-09-28

    Kinetics and equilibrium are studied on the hydrothermal decarbonylation and decarboxylation of formic acid, the intermediate of the water-gas-shift (WGS) reaction, in hot water at temperatures of 170-330 degrees C, to understand and control the hydrothermal WGS reaction. (1)H and (13)C NMR spectroscopy is applied to analyze as a function of time the quenched reaction mixtures in both the liquid and gas phases. Only the decarbonylation is catalyzed by HCl, and the reaction is first-order with respect to both [H(+)] and [HCOOH]. Consequently, the reaction without HCl is first and a half (1.5) order due to the unsuppressed ionization of formic acid. The HCl-accelerated decarbonylation path can thus be separated in time from the decarboxylation. The rate and equilibrium constants for the decarbonylation are determined separately by using the Henry constant (gas solubility data) for carbon monoxide in hot water. The rate constant for the decarbonylation is 1.5 x 10(-5), 2.0 x 10(-4), 3.7 x 10(-3), and 6.3 x 10(-2) mol(-1) kg s(-1), respectively, at 170, 200, 240, and 280 degrees C on the liquid branch of the saturation curve. The Arrhenius plot of the decarbonylation is linear and gives the activation energy as 146 +/- 3 kJ mol(-1). The equilibrium constant K(CO) = [CO]/[HCOOH] is 0.15, 0.33, 0.80, and 4.2, respectively, at 170, 200, 240, and 280 degrees C. The van't Hoff plot results in the enthalpy change of DeltaH = 58 +/- 6 kJ mol(-1). The decarboxylation rate is also measured at 240-330 degrees C in both acidic and basic conditions. The rate is weakly dependent on the solution pH and is of the order of 10(-4) mol kg(-1) s(-1) at 330 degrees C. Furthermore, the equilibrium constant K(CO2) = [CO(2)][H(2)]/[HCOOH] is estimated to be 1.0 x10(2) mol kg(-1) at 330 degrees C. PMID:16986841

  12. A Mechanistic Approach for Simulating Root Water Uptake Regulation by Plants in Soils with Heterogeneous Water Distribution

    NASA Astrophysics Data System (ADS)

    Huber, K.; Vanderborght, J.; Javaux, M.; Vereecken, H.

    2012-12-01

    Transpiration by plants is a key component of the terrestrial water cycle. Besides being controlled by atmospheric demand, plant transpiration depends also on availability of soil water for uptake by plant roots. In situations where potential transpiration cannot be upheld by available soil water plants have developed different strategies, i.e. isohydric and anisohydric [Tardieu and Simmoneau, 1998] leaf water potentials, for the adjustment of their water consumption. The quantification of water availability in soils and the regulation of root water uptake in land surface models are generally lacking strong empirical and mechanistic foundations. In this contribution we present a mechanistic modeling approach to address these issues. We used the model R-SWMS and built in three different possible plant physiological reactions on spatial variations in water availability in the root zone, as are often artificially created in split-root experiments. Two approaches were based on pure hydraulic regulation while for the third scenario an additional signal generated at the root tips was introduced. We could show that this signaling leads to a transpiration reduction for heterogeneous water distributions in the soil, even though the absolute amount of available water would be sufficient to maintain potential transpiration if it were only hydraulically controlled. Model simulations were subsequently used to evaluate the impact of signaling on transpiration reduction that was observed in split root experiments reported in the literature [Dodd et al., 2010]. Model simulations using R-SWMS for more natural soil and weather conditions could be used in future to parameterize the relation between soil water availability and transpiration in large scale land surface models and offer the possibility to include plant properties or plant species dependent regulation mechanisms in these parameterizations.

  13. Hydrogen iodide decomposition

    DOEpatents

    O'Keefe, Dennis R.; Norman, John H.

    1983-01-01

    Liquid hydrogen iodide is decomposed to form hydrogen and iodine in the presence of water using a soluble catalyst. Decomposition is carried out at a temperature between about 350.degree. K. and about 525.degree. K. and at a corresponding pressure between about 25 and about 300 atmospheres in the presence of an aqueous solution which acts as a carrier for the homogeneous catalyst. Various halides of the platinum group metals, particularly Pd, Rh and Pt, are used, particularly the chlorides and iodides which exhibit good solubility. After separation of the H.sub.2, the stream from the decomposer is countercurrently extracted with nearly dry HI to remove I.sub.2. The wet phase contains most of the catalyst and is recycled directly to the decomposition step. The catalyst in the remaining almost dry HI-I.sub.2 phase is then extracted into a wet phase which is also recycled. The catalyst-free HI-I.sub.2 phase is finally distilled to separate the HI and I.sub.2. The HI is recycled to the reactor; the I.sub.2 is returned to a reactor operating in accordance with the Bunsen equation to create more HI.

  14. 18 CFR 420.51 - Hydroelectric power plant water use charges.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 18 Conservation of Power and Water Resources 2 2011-04-01 2011-04-01 false Hydroelectric power plant water use charges. 420.51 Section 420.51 Conservation of Power and Water Resources DELAWARE RIVER BASIN COMMISSION ADMINISTRATIVE MANUAL BASIN REGULATIONS-WATER SUPPLY CHARGES Hydroelectric Power...

  15. 18 CFR 420.51 - Hydroelectric power plant water use charges.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 18 Conservation of Power and Water Resources 2 2010-04-01 2010-04-01 false Hydroelectric power plant water use charges. 420.51 Section 420.51 Conservation of Power and Water Resources DELAWARE RIVER BASIN COMMISSION ADMINISTRATIVE MANUAL BASIN REGULATIONS-WATER SUPPLY CHARGES Hydroelectric Power...

  16. Evaluation of coal-gasification - combustion-turbine power plants emphasizing low water consumption

    SciTech Connect

    Cavazo, R.; Clemmer, A.B.; de la Mora, J.A.; Grisso, J.R.; Klumpe, H.W.; Meissner, R.E.; Musso, A.; Roszkowski, T.R.

    1982-01-01

    A cost and performance study was made of several integrated power plants using coal gasification technology now in advanced development and combustion turbines for power generation. The principal emphasis was placed on studying plants using air cooling and comparing costs and performance of those plants with water-cooled coal gasification-combined-cycle (GCC) and conventional coal-fired power plants. The major objective was to determine whether cost and performance penalties would be prohibitive for air-cooled plants that use yet-to-be-developed coal gasifiers and commercially available combustion turbines for topping cycle power. The results indicate the following: air-cooled GCC plants using conceptual designs of either the Texaco or the British Gas Corporation (BGC) slaging gasifier could have coal-to-net electric power efficiencies equivalent to that of a water-cooled conventional coal-fired plant; the air-cooled GCC plants could produce electricity at busbar cost 1 to 3 mills per kWh (1980 dollars) less than busbar cost in a water-cooled conventional plant and only up to 2 mills per kWh higher than busbar cost in a water-cooled Texaco GCC plant; and even a simple-cycle regenerative combustion turbine plant fueled with gas from the BGC gasifier could have a coal-to-net electric power efficiency of over 30% and a busbar cost competitive with that in a water cooled conventional plant. The principal reason that air-cooled power plants using combustion turbines could be competitive with conventional water-cooled, coal-fired steam plants is that a majority of net power is produced by the combustion turbines, which require no cooling water. This, in turn, leads to a reduced cost and performance penalty when bottoming steam-cycle condensers are air-cooled.

  17. Geographic, technologic, and economic analysis of using reclaimed water for thermoelectric power plant cooling.

    PubMed

    Stillwell, Ashlynn S; Webber, Michael E

    2014-04-15

    Use of reclaimed water-municipal wastewater treatment plant effluent-in nonpotable applications can be a sustainable and efficient water management strategy. One such nonpotable application is at thermoelectric power plants since these facilities require cooling, often using large volumes of freshwater. To evaluate the geographic, technologic, and economic feasibility of using reclaimed water to cool thermoelectric power plants, we developed a spatially resolved model of existing power plants. Our model integrates data on power plant and municipal wastewater treatment plant operations into a combined geographic information systems and optimization approach to evaluate the feasibility of cooling system retrofits. We applied this broadly applicable methodology to 125 power plants in Texas as a test case. Results show that sufficient reclaimed water resources exist within 25 miles of 92 power plants (representing 61% of capacity and 50% of generation in our sample), with most of these facilities meeting both short-term and long-term water conservation cost goals. This retrofit analysis indicates that reclaimed water could be a suitable cooling water source for thermoelectric power plants, thereby mitigating some of the freshwater impacts of electricity generation. PMID:24625241

  18. Evaluation of Effectiveness Technological Process of Water Purification Exemplified on Modernized Water Treatment Plant at Otoczna

    NASA Astrophysics Data System (ADS)

    Jordanowska, Joanna; Jakubus, Monika

    2014-12-01

    The article presents the work of the Water Treatment Plant in the town of Otoczna, located in the Wielkopolska province, before and after the modernization of the technological line. It includes the quality characteristics of the raw water and treated water with particular emphasis on changes in the quality indicators in the period 2002 -2012 in relation to the physicochemical parameters: the content of total iron and total manganese, the ammonium ion as well as organoleptic parameters(colour and turbidity). The efficiency of technological processes was analysed, including the processes of bed start up with chalcedonic sand to remove total iron and manganese and ammonium ion. Based on the survey, it was found that the applied modernization helped solve the problem of water quality, especially the removal of excessive concentrations of iron, manganese and ammonium nitrogen from groundwater. It has been shown that one year after modernization of the technological line there was a high reduction degree of most parameters, respectively for the general iron content -99%, general manganese - 93% ammonia - 93%, turbidity - 94%. It has been proved, that chalcedonic turned out to be better filter material than quartz sand previously used till 2008. The studies have confirmed that the stage of modernization was soon followed by bed start-up for removing general iron from the groundwater. The stage of manganese removal required more time, about eight months for bed start-up. Furthermore, the technological modernization contributed to the improvement of the efficiency of the nitrification process.

  19. Management intensity alters decomposition via biological pathways

    USGS Publications Warehouse

    Wickings, Kyle; Grandy, A. Stuart; Reed, Sasha; Cleveland, Cory

    2011-01-01

    Current conceptual models predict that changes in plant litter chemistry during decomposition are primarily regulated by both initial litter chemistry and the stage-or extent-of mass loss. Far less is known about how variations in decomposer community structure (e.g., resulting from different ecosystem management types) could influence litter chemistry during decomposition. Given the recent agricultural intensification occurring globally and the importance of litter chemistry in regulating soil organic matter storage, our objectives were to determine the potential effects of agricultural management on plant litter chemistry and decomposition rates, and to investigate possible links between ecosystem management, litter chemistry and decomposition, and decomposer community composition and activity. We measured decomposition rates, changes in litter chemistry, extracellular enzyme activity, microarthropod communities, and bacterial versus fungal relative abundance in replicated conventional-till, no-till, and old field agricultural sites for both corn and grass litter. After one growing season, litter decomposition under conventional-till was 20% greater than in old field communities. However, decomposition rates in no-till were not significantly different from those in old field or conventional-till sites. After decomposition, grass residue in both conventional- and no-till systems was enriched in total polysaccharides relative to initial litter, while grass litter decomposed in old fields was enriched in nitrogen-bearing compounds and lipids. These differences corresponded with differences in decomposer communities, which also exhibited strong responses to both litter and management type. Overall, our results indicate that agricultural intensification can increase litter decomposition rates, alter decomposer communities, and influence litter chemistry in ways that could have important and long-term effects on soil organic matter dynamics. We suggest that future

  20. Estimating plant available water for general crop simulations in ALMANAC/APEX/EPIC/SWAT

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Process-based simulation models ALMANAC/APEX/EPIC/SWAT contain generalized plant growth subroutines to predict biomass and crop yield. Environmental constraints typically restrict plant growth and yield. Water stress is often an important limiting factor; it is calculated as the sum of water use f...

  1. A Series RCL Circuit Theory for Analyzing Non-Steady-State Water Uptake of Maize Plants

    PubMed Central

    Zhuang, Jie; Yu, Gui-Rui; Nakayama, Keiichi

    2014-01-01

    Understanding water uptake and transport through the soil-plant continuum is vital for ecosystem management and agricultural water use. Plant water uptake under natural conditions is a non-steady transient flow controlled by root distribution, plant configuration, soil hydraulics, and climatic conditions. Despite significant progress in model development, a mechanistic description of transient water uptake has not been developed or remains incomplete. Here, based on advanced electrical network theory (RLC circuit theory), we developed a non-steady state biophysical model to mechanistically analyze the fluctuations of uptake rates in response to water stress. We found that the non-steady-state model captures the nature of instantaneity and hysteresis of plant water uptake due to the considerations of water storage in plant xylem and coarse roots (capacitance effect), hydraulic architecture of leaf system (inductance effect), and soil-root contact (fuse effect). The model provides insights into the important role of plant configuration and hydraulic heterogeneity in helping plants survive an adverse environment. Our tests against field data suggest that the non-steady-state model has great potential for being used to interpret the smart water strategy of plants, which is intrinsically determined by stem size, leaf size/thickness and distribution, root system architecture, and the ratio of fine-to-coarse root lengths. PMID:25335512

  2. A series RCL circuit theory for analyzing non-steady-state water uptake of maize plants.

    PubMed

    Zhuang, Jie; Yu, Gui-Rui; Nakayama, Keiichi

    2014-01-01

    Understanding water uptake and transport through the soil-plant continuum is vital for ecosystem management and agricultural water use. Plant water uptake under natural conditions is a non-steady transient flow controlled by root distribution, plant configuration, soil hydraulics, and climatic conditions. Despite significant progress in model development, a mechanistic description of transient water uptake has not been developed or remains incomplete. Here, based on advanced electrical network theory (RLC circuit theory), we developed a non-steady state biophysical model to mechanistically analyze the fluctuations of uptake rates in response to water stress. We found that the non-steady-state model captures the nature of instantaneity and hysteresis of plant water uptake due to the considerations of water storage in plant xylem and coarse roots (capacitance effect), hydraulic architecture of leaf system (inductance effect), and soil-root contact (fuse effect). The model provides insights into the important role of plant configuration and hydraulic heterogeneity in helping plants survive an adverse environment. Our tests against field data suggest that the non-steady-state model has great potential for being used to interpret the smart water strategy of plants, which is intrinsically determined by stem size, leaf size/thickness and distribution, root system architecture, and the ratio of fine-to-coarse root lengths. PMID:25335512

  3. A Series RCL Circuit Theory for Analyzing Non-Steady-State Water Uptake of Maize Plants

    NASA Astrophysics Data System (ADS)

    Zhuang, Jie; Yu, Gui-Rui; Nakayama, Keiichi

    2014-10-01

    Understanding water uptake and transport through the soil-plant continuum is vital for ecosystem management and agricultural water use. Plant water uptake under natural conditions is a non-steady transient flow controlled by root distribution, plant configuration, soil hydraulics, and climatic conditions. Despite significant progress in model development, a mechanistic description of transient water uptake has not been developed or remains incomplete. Here, based on advanced electrical network theory (RLC circuit theory), we developed a non-steady state biophysical model to mechanistically analyze the fluctuations of uptake rates in response to water stress. We found that the non-steady-state model captures the nature of instantaneity and hysteresis of plant water uptake due to the considerations of water storage in plant xylem and coarse roots (capacitance effect), hydraulic architecture of leaf system (inductance effect), and soil-root contact (fuse effect). The model provides insights into the important role of plant configuration and hydraulic heterogeneity in helping plants survive an adverse environment. Our tests against field data suggest that the non-steady-state model has great potential for being used to interpret the smart water strategy of plants, which is intrinsically determined by stem size, leaf size/thickness and distribution, root system architecture, and the ratio of fine-to-coarse root lengths.

  4. Improvement of growth rate of plants by bubble discharge in water

    NASA Astrophysics Data System (ADS)

    Takahata, Junichiro; Takaki, Koichi; Satta, Naoya; Takahashi, Katsuyuki; Fujio, Takuya; Sasaki, Yuji

    2015-01-01

    The effect of bubble discharge in water on the growth rate of plants was investigated experimentally for application to plant cultivation systems. Spinach (Spinacia oleracea), radish (Raphanus sativus var. sativus), and strawberry (Fragaria × ananassa) were used as specimens to clarify the effect of the discharge treatment on edible parts of the plants. The specimens were cultivated in pots filled with artificial soil, which included chicken manure charcoal. Distilled water was sprayed on the artificial soil and drained through a hole in the pots to a water storage tank. The water was circulated from the water storage tank to the cultivation pots after 15 or 30 min discharge treatment on alternate days. A magnetic compression-type pulsed power generator was used to produce the bubble discharge with a repetition rate of 250 pps. The plant height in the growth phase and the dry weight of the harvested plants were improved markedly by the discharge treatment in water. The soil and plant analyzer development (SPAD) value of the plants also improved in the growth phase of the plants. The concentration of nitrate nitrogen, which mainly contributed to the improvement of the growth rate, in the water increased with the discharge treatment. The Brix value of edible parts of Fragaria × ananassa increased with the discharge treatment. The inactivation of bacteria in the water was also confirmed with the discharge treatment.

  5. ONE MGD ION EXCHANGE PLANT FOR REMOVAL OF NITRATE FROM WELL WATER

    EPA Science Inventory

    A full scale 1 mgd demonstration plant, using ion exchange, for removal of nitrate from well water was built at McFarland, California. The plant has been performing satisfactorily in the semi-automatic mode since October 1983. Full automation of the plant was completed in June 19...

  6. Evaluation of Irrigation Methods for Highbush Blueberry. I. Growth and Water Requirements of Young Plants

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A study was conducted in a new field of northern highbush blueberry (Vaccinium corymbosum L. 'Elliott') to determine the effects of different irrigation methods on growth and water requirements of uncropped plants during the first 2 years after planting. The plants were grown on mulched, raised beds...

  7. Chlorophyll fluorescence as an indicator of plant water status in cotton

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Various methods exist for the measurement of plant water status. Plant breeders value methods that are fast and inexpensive lending themselves to the efficient evaluation of large segregating populations. Chlorophyll fluorescence is a parameter commonly measured by plant physiologists when studying ...

  8. Implications of Transitioning from De Facto to Engineered Water Reuse for Power Plant Cooling.

    PubMed

    Barker, Zachary A; Stillwell, Ashlynn S

    2016-05-17

    Thermoelectric power plants demand large quantities of cooling water, and can use alternative sources like treated wastewater (reclaimed water); however, such alternatives generate many uncertainties. De facto water reuse, or the incidental presence of wastewater effluent in a water source, is common at power plants, representing baseline conditions. In many cases, power plants would retrofit open-loop systems to cooling towers to use reclaimed water. To evaluate the feasibility of reclaimed water use, we compared hydrologic and economic conditions at power plants under three scenarios: quantified de facto reuse, de facto reuse with cooling tower retrofits, and modeled engineered reuse conditions. We created a genetic algorithm to estimate costs and model optimal conditions. To assess power plant performance, we evaluated reliability metrics for thermal variances and generation capacity loss as a function of water temperature. Applying our analysis to the greater Chicago area, we observed high de facto reuse for some power plants and substantial costs for retrofitting to use reclaimed water. Conversely, the gains in reliability and performance through engineered reuse with cooling towers outweighed the energy investment in reclaimed water pumping. Our analysis yields quantitative results of reclaimed water feasibility and can inform sustainable management of water and energy. PMID:27077957

  9. RESPONSES OF WETLAND PLANTS TO EFFLUENTS IN WATER & SEDIMENT

    EPA Science Inventory

    Responses of two wetland vascular plants, Echinochloa crusgalli and Sesbania macrocarpa, exposed to effluents from a coke plant, a pulp mill, a wastewater treatment plant, and the herbicide, hexazinone, were measured in three types of tests: seed germination and early growth, see...

  10. POWER PLANT COOLING WATER CHLORINATION IN NORTHERN CALIFORNIA

    EPA Science Inventory

    A survey was conducted of chlorination practices at five power plants owned and operated by the Pacific Gas and Electric Company. Frequency and duration of chlorination varied significantly from plant to plant and was controlled analytically by the orthotolidine and/or amperometr...

  11. Estimating spatially distributed soil water content at small watershed scales based on decomposition of temporal anomaly and time stability analysis

    NASA Astrophysics Data System (ADS)

    Hu, W.; Si, B. C.

    2016-02-01

    Soil water content (SWC) is crucial to rainfall-runoff response at the watershed scale. A model was used to decompose the spatiotemporal SWC into a time-stable pattern (i.e., temporal mean), a space-invariant temporal anomaly, and a space-variant temporal anomaly. The space-variant temporal anomaly was further decomposed using the empirical orthogonal function (EOF) for estimating spatially distributed SWC. This model was compared to a previous model that decomposes the spatiotemporal SWC into a spatial mean and a spatial anomaly, with the latter being further decomposed using the EOF. These two models are termed the temporal anomaly (TA) model and spatial anomaly (SA) model, respectively. We aimed to test the hypothesis that underlying (i.e., time-invariant) spatial patterns exist in the space-variant temporal anomaly at the small watershed scale, and to examine the advantages of the TA model over the SA model in terms of the estimation of spatially distributed SWC. For this purpose, a data set of near surface (0-0.2 m) and root zone (0-1.0 m) SWC, at a small watershed scale in the Canadian Prairies, was analyzed. Results showed that underlying spatial patterns exist in the space-variant temporal anomaly because of the permanent controls of static factors such as depth to the CaCO3 layer and organic carbon content. Combined with time stability analysis, the TA model improved the estimation of spatially distributed SWC over the SA model, especially for dry conditions. Further application of these two models demonstrated that the TA model outperformed the SA model at a hillslope in the Chinese Loess Plateau, but the performance of these two models in the GENCAI network (˜ 250 km2) in Italy was equivalent. The TA model can be used to construct a high-resolution distribution of SWC at small watershed scales from coarse-resolution remotely sensed SWC products.

  12. POTENTIAL WATER QUANTITY AND WATER QUALITY IMPACTS OF POWER PLANT DEVELOPMENT SCENARIOS ON MAJOR RIVERS IN THE OHIO BASIN

    EPA Science Inventory

    This report was prepared in support of the Ohio River Basin Energy Study (ORBES), a multidisciplinary policy research program supported by the Environmental Protection Agency. Water consumption levels associated with power plant cooling were estimated for different energy develop...

  13. Optimal plant water use across temporal scales: bridging eco-hydrological theories and plant eco-physiological responses

    NASA Astrophysics Data System (ADS)

    Manzoni, S.; Vico, G.; Palmroth, S.; Katul, G. G.; Porporato, A. M.

    2013-12-01

    In terrestrial ecosystems, plant photosynthesis occurs at the expense of water losses through stomata, thus creating an inherent hydrologic constrain to carbon (C) gains and productivity. While such a constraint cannot be overcome, evolution has led to a number of adaptations that allow plants to thrive under highly variable and often limiting water availability. It may be hypothesized that these adaptations are optimal and allow maximum C gain for a given water availability. A corollary hypothesis is that these adaptations manifest themselves as coordination between the leaf photosynthetic machinery and the plant hydraulic system. This coordination leads to functional relations between the mean hydrologic state, plant hydraulic traits, and photosynthetic parameters that can be used as bridge across temporal scales. Here, optimality theories describing the behavior of stomata and plant morphological features in a fluctuating soil moisture environment are proposed. The overarching goal is to explain observed global patterns of plant water use and their ecological and biogeochemical consequences. The problem is initially framed as an optimal control problem of stomatal closure during drought of a given duration, where maximizing the total photosynthesis under limited and diminishing water availability is the objective function. Analytical solutions show that commonly used transpiration models (in which stomatal conductance is assumed to depend on soil moisture) are particular solutions emerging from the optimal control problem. Relations between stomatal conductance, vapor pressure deficit, and atmospheric CO2 are also obtained without any a priori assumptions under this framework. Second, the temporal scales of the model are expanded by explicitly considering the stochasticity of rainfall. In this context, the optimal control problem becomes a maximization problem for the mean photosynthetic rate. Results show that to achieve maximum C gains under these

  14. The use of soil electrical resistivity to monitor plant and soil water relationships in vineyards

    NASA Astrophysics Data System (ADS)

    Brillante, L.; Mathieu, O.; Bois, B.; van Leeuwen, C.; Lévêque, J.

    2015-03-01

    Soil water availability deeply affects plant physiology. In viticulture it is considered a major contributor to the "terroir" effect. The assessment of soil water in field conditions is a difficult task, especially over large surfaces. New techniques are therefore required in order to better explore variations of soil water content in space and time with low disturbance and with great precision. Electrical resistivity tomography (ERT) meets these requirements for applications in plant sciences, agriculture and ecology. In this paper, possible techniques to develop models that allow the use of ERT to spatialise soil water available to plants are reviewed. An application of soil water monitoring using ERT in a grapevine plot in Burgundy (north-east France) during the vintage 2013 is presented. We observed the lateral heterogeneity of ERT-derived fraction of transpirable soil water (FTSW) variations, and differences in water uptake depend on grapevine water status (leaf water potentials measured both at predawn and at solar noon and contemporary to ERT monitoring). Active zones in soils for water movements were identified. The use of ERT in ecophysiological studies, with parallel monitoring of plant water status, is still rare. These methods are promising because they have the potential to reveal a hidden part of a major function of plant development: the capacity to extract water from the soil.

  15. Foliar absorption of intercepted rainfall improves woody plant water status most during drought.

    PubMed

    Breshears, David D; McDowell, Nathan G; Goddard, Kelly L; Dayem, Katherine E; Martens, Scott N; Meyer, Clifton W; Brown, Karen M

    2008-01-01

    A large proportion of rainfall in dryland ecosystems is intercepted by plant foliage and is generally assumed to evaporate to the atmosphere or drip onto the soil surface without being absorbed. We demonstrate foliar absorption of intercepted rainfall in a widely distributed, continental dryland, woody-plant genus: Juniperus. We observed substantial improvement in plant water status, exceeding 1.0 MPa water potential for drought-stressed plants, following precipitation on an experimental plot that excluded soil water infiltration. Experiments that wetted shoots with unlabeled and with isotopically labeled water confirmed that water potential responded substantially to foliar wetting, that these responses were not attributable to re-equilibration with other portions of the xylem, and that magnitude of response increased with water stress. Foliar absorption is not included in most ecological, hydrological, and atmospheric models; has implications for interpreting plant isotopic signatures; and not only supplements water acquisition associated with increases in soil moisture that follow large or repeated precipitation events, but also enables plants to bypass soil water uptake and benefit from the majority of precipitation events, which wet foliage but do not increase soil moisture substantially. Foliar absorption of intercepted water could be more important than previously appreciated, especially during drought when water stress is greatest. PMID:18376545

  16. Mechanics of water collection in plants via morphology change of conical hairs

    NASA Astrophysics Data System (ADS)

    Ito, Fuyu; Komatsubara, Satoshi; Shigezawa, Naoki; Morikawa, Hideaki; Murakami, Yasushi; Yoshino, Katsumi; Yamanaka, Shigeru

    2015-03-01

    In an arid area like the Namib Desert, plants and animals obtain moisture needed for life from mist in the air. There, some plants have hairs or fibrous structures on their leaf surface that reportedly collect fresh water from the air. We examined the morphology and function of leaf hairs of plants during water collection under different circumstances. We studied the water collecting mechanics of several plants having fibrous hairs on their leaves: tomato, balsam pear, Berkheya purpurea, and Lychnis sieboldii. This plant was selected for detailed investigation as a model because this plant originated from dry grassland near Mount Aso in Kyusyu, Japan. We found a unique feature of water collection and release in this plant. The cone-shaped hairs having inner microfibers were reversibly converted to crushed plates that were twisted perpendicularly in dry conditions. Microfibers found in the hairs seem to be responsible for water storage and release. Their unique reciprocal morphological changes, cone-shaped hairs transformed into perpendicularly twisted shapes, depend on the moisture level in the air, and water stored during wet external conditions was released onto the leaf in drier conditions. These morphological changes were recorded as a movie. Simulations explained the formation of the twisted structure. In theoretical analyses, twisted structures were found to give higher mechanical strength. Similar phenomena were found in the other plants described above. These findings pave the way to new bioinspired technology for alleviating global water shortages.

  17. [Effects of large-area planting water hyacinth on macro-benthos community structure and biomass].

    PubMed

    Liu, Guo-Feng; Liu, Hai-Qin; Zhang, Zhi-Yong; Zhang, Ying-Ying; Yan, Shao-Hua; Zhong, Ji-Cheng; Fan, Cheng-Xin

    2010-12-01

    The effects on macro-benthos and benthos environment of planting 200 hm2 water hyacinth (E. crassipens) in Zhushan Bay, Lake Taihu, were studied during 8-10 months consecutive surveys. Results indicated that average densities of mollusca (the main species were Bellamya aeruginosa) in far-planting, near-planting and planting area were 276.67, 371.11 and 440.00 ind/m2, respectively, and biomass were 373.15, 486.57 and 672.54 g/m2, respectively, showed that average density and biomass of planting area's were higher than those of others. However, the average density and biomass of Oligochaeta (the main species was Limodrilus hoffmeisteri) and Chironomidae in planting area were lower than that of outside planting area. The density and biomass of three dominant species of benthic animal increased quickly during 8-9 months, decreased quickly in October inside and outside water hyacinth planting area. The reason of this phenomenon could be possible that lots of cyanobacteria cells died and consumed dissolve oxygen in proceed decomposing. Algae cells released lots of phosphorus and nitrogen simultaneously, so macro-benthos died in this environment. The indexes of Shannon-Weaver and Simpson indicated that water environment was in moderate polluted state. On the basis of the survey results, the large-area and high-density planting water hyacinth haven't demonstrated a great impact on macrobenthos and benthos environment in short planting time (about 6 months planting time). PMID:21360881

  18. Temperature, oxygen, and vegetation controls on decomposition in a James Bay peatland

    NASA Astrophysics Data System (ADS)

    Philben, Michael; Holmquist, James; MacDonald, Glen; Duan, Dandan; Kaiser, Karl; Benner, Ronald

    2015-06-01

    The biochemical composition of a peat core from James Bay Lowland, Canada, was used to assess the extent of peat decomposition and diagenetic alteration. Our goal was to identify environmental controls on peat decomposition, particularly its sensitivity to naturally occurring changes in temperature, oxygen exposure time, and vegetation. All three varied substantially during the last 7000 years, providing a natural experiment for evaluating their effects on decomposition. The bottom 50 cm of the core formed during the Holocene Climatic Optimum (~7000-4000 years B.P.), when mean annual air temperature was likely 1-2°C warmer than present. A reconstruction of the water table level using testate amoebae indicated oxygen exposure time was highest in the subsequent upper portion of the core between 150 and 225 cm depth (from ~2560 to 4210 years B.P.) and the plant community shifted from mostly Sphagnum to vascular plant dominance. Several independent biochemical indices indicated that decomposition was greatest in this interval. Hydrolysable amino acid yields, hydroxyproline yields, and acid:aldehyde ratios of syringyl lignin phenols were higher, while hydrolysable neutral sugar yields and carbon:nitrogen ratios were lower in this zone of both vascular plant vegetation and elevated oxygen exposure time. Thus, peat formed during the Holocene Climatic Optimum did not appear to be more extensively decomposed than peat formed during subsequent cooler periods. Comparison with a core from the West Siberian Lowland, Russia, indicates that oxygen exposure time and vegetation are both important controls on decomposition, while temperature appears to be of secondary importance. The low apparent sensitivity of decomposition to temperature is consistent with recent observations of a positive correlation between peat accumulation rates and mean annual temperature, suggesting that contemporary warming could enhance peatland carbon sequestration, although this could be offset by an

  19. Low Temperature Water-Gas Shift: Type and Loading of Metal Impacts Decomposition and Hydrogen Exchange Rates of Pseudo-stabilized Formate over Metal/ceria Catalysts

    SciTech Connect

    Jacobs,G.; Ricote, S.; Davis, B.

    2006-01-01

    In this investigation, a similar degree of surface shell reduction among a series of metal promoted ceria catalysts was established by diffuse reflectance Fourier transform infrared spectroscopy (DRIFTS) and X-ray absorption near-edge spectroscopy (XANES) measurements. Surface formate species were generated by reaction of CO with bridging OH groups associated with the Ce{sup 3+} defect sites. The thermal decomposition of the pseudo-stable formates was followed in the absence of H2O. Decomposition and exchange from H to D of the pseudo-stabilized formate was enhanced by changing the promoter from Au to Pt. Likewise, an increase was observed in both decomposition and exchange rates by increasing the promoter loading from 0.5 to 2.5 wt.%. The results suggest that C{single_bond}H bond breaking is facilitated during this thermal decomposition (i.e., reverse decomposition to CO and {single_bond}OH). Therefore, since the rate limiting step of the forward formate decomposition (i.e., the WGS reaction) is strongly suggested to be associated with C{single_bond}H bond cleaving in the formate intermediate (based on earlier kinetic isotope effect and isotopic tracer studies), the results can explain the promotion in the WGS rates as observed by changing from Au to Pt and by increased promoter loading.

  20. Nested Taylor decomposition in multivariate function decomposition

    NASA Astrophysics Data System (ADS)

    Baykara, N. A.; Gürvit, Ercan

    2014-12-01

    Fluctuationlessness approximation applied to the remainder term of a Taylor decomposition expressed in integral form is already used in many articles. Some forms of multi-point Taylor expansion also are considered in some articles. This work is somehow a combination these where the Taylor decomposition of a function is taken where the remainder is expressed in integral form. Then the integrand is decomposed to Taylor again, not necessarily around the same point as the first decomposition and a second remainder is obtained. After taking into consideration the necessary change of variables and converting the integration limits to the universal [0;1] interval a multiple integration system formed by a multivariate function is formed. Then it is intended to apply the Fluctuationlessness approximation to each of these integrals one by one and get better results as compared with the single node Taylor decomposition on which the Fluctuationlessness is applied.

  1. Thermoeconomic optimizarion of OC-OTEC electricity and water production plants. Final report

    SciTech Connect

    Block, D.L.; Girgis, M.A.; Huggins, J.C.; McCluney, R.; Rotundo, L.; Valenzuela, J.A.; Hutchings, B.J.; Stacy, W.D.; Sam, R.G.; Patel, B.R.

    1984-09-01

    The objectives of this yearlong project were to: (1) assess the economic and technical viability of open-cycle ocean thermal energy conversion of (OC-OTEC) for the production of electricity and/or fresh water based on the current state of the art; (2) develop conceptual designs of optimized OC-OTEC plants that produce electricity and/or fresh water for plant sizes that are economically attractive; and (3) identify the research issues that must be resolved before a commercial plant can be built. Oceanographic data for six potential sites were evaluated and generic site characteristics were developed. The generic site has a 20/sup 0/C temperature differential between the ocean surface and a depth of 1000 m. This temperature differential occurs at a distance of 5 km from shore. Current and projected prices and requirements for electricity and water at potential sites were obtained. The state of the art of components comprising the OC-OTEC plant was reviewed. Design options for each component were identified. The highest performing, least costly, and least technically uncertain design for each component was selected. Component cost and performance models were then developed and integrated into thermoeconomic system models for single- and double-stage OC-OTEC plants that produced electricity and/or fresh water. A computerized optimization procedure was developed to obtain optimal (minimum cost) plant configurations for the production of electricity and/or fresh water. All plant types - floating, moored, shelf-mounted, shallow-water and land-based plants - were evaluated. Based on the state-of-the-art and typical characteristics of potential sites, the primary thrust of the program was directed towards shallow-water and land-based plants. The shallow-water/land-based plant configurations selected had a 5-km long cold-water supply pipe and a 1-km long discharge pipe for the evaporator and condenser.

  2. Hydrogen production from water decomposition by redox of Fe{sub 2}O{sub 3} modified with single- or double-metal additives

    SciTech Connect

    Liu Xiaojie; Wang Hui

    2010-05-15

    Iron oxide modified with single- or double-metal additives (Cr, Ni, Zr, Ag, Mo, Mo-Cr, Mo-Ni, Mo-Zr and Mo-Ag), which can store and supply pure hydrogen by reduction of iron oxide with hydrogen and subsequent oxidation of reduced iron oxide with steam (Fe{sub 3}O{sub 4} (initial Fe{sub 2}O{sub 3})+4H{sub 2}reversible3Fe+4H{sub 2}O), were prepared by impregnation. Effects of various metal additives in the samples on hydrogen production were investigated by the above-repeated redox. All the samples with Mo additive exhibited a better redox performance than those without Mo, and the Mo-Zr additive in iron oxide was the best effective one enhancing hydrogen production from water decomposition. For Fe{sub 2}O{sub 3}-Mo-Zr, the average H{sub 2} production temperature could be significantly decreased to 276 deg. C, the average H{sub 2} formation rate could be increased to 360.9-461.1 {mu}mol min{sup -1} Fe-g{sup -1} at operating temperature of 300 deg. C and the average storage capacity was up to 4.73 wt% in four cycles, an amount close to the IEA target. - Graphical abstract: Mo+Zr additive has the best modified effect on improving the redox performances of Fe{sub 2}O{sub 3}:H{sub 2} producing temperature of 276 deg. C and hydrogen storage capacity of 4.73 wt%.

  3. Wheat streak mosaic: A classic case of plant disease impact on soil water content and crop water-use efficiency

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In this article, we describe the relationship between wheat streak mosaic (WSM) severity and soil water content as a prime example of the effect of a plant disease on soil water status and its implications for irrigated agriculture. The present study was part of a larger investigation which included...

  4. Wheat Streak Mosaic: A classic case of plant disease impact on soil water content and crop water-use efficiency

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In this article, we describe the relationship between wheat streak mosaic (WSM) severity and soil water content as a prime example of the effect of a plant disease on soil water status and its implications for irrigated agriculture. The present study was part of a larger investigation which included...

  5. Water impacts of CO2 emission performance standards for fossil fuel-fired power plants.

    PubMed

    Talati, Shuchi; Zhai, Haibo; Morgan, M Granger

    2014-10-21

    We employ an integrated systems modeling tool to assess the water impacts of the new source performance standards recently proposed by the U.S. Environmental Protection Agency for limiting CO2 emissions from coal- and gas-fired power plants. The implementation of amine-based carbon capture and storage (CCS) for 40% CO2 capture to meet the current proposal will increase plant water use by roughly 30% in supercritical pulverized coal-fired power plants. The specific amount of added water use varies with power plant and CCS designs. More stringent emission standards than the current proposal would require CO2 emission reductions for natural gas combined-cycle (NGCC) plants via CCS, which would also increase plant water use. When examined over a range of possible future emission standards from 1100 to 300 lb CO2/MWh gross, new baseload NGCC plants consume roughly 60-70% less water than coal-fired plants. A series of adaptation approaches to secure low-carbon energy production and improve the electric power industry's water management in the face of future policy constraints are discussed both quantitatively and qualitatively. PMID:25229670

  6. Irrigation water sources and irrigation application methods used by U.S. plant nursery producers

    NASA Astrophysics Data System (ADS)

    Paudel, Krishna P.; Pandit, Mahesh; Hinson, Roger

    2016-02-01

    We examine irrigation water sources and irrigation methods used by U.S. nursery plant producers using nested multinomial fractional regression models. We use data collected from the National Nursery Survey (2009) to identify effects of different firm and sales characteristics on the fraction of water sources and irrigation methods used. We find that regions, sales of plants types, farm income, and farm age have significant roles in what water source is used. Given the fraction of alternative water sources used, results indicated that use of computer, annual sales, region, and the number of IPM practices adopted play an important role in the choice of irrigation method. Based on the findings from this study, government can provide subsidies to nursery producers in water deficit regions to adopt drip irrigation method or use recycled water or combination of both. Additionally, encouraging farmers to adopt IPM may enhance the use of drip irrigation and recycled water in nursery plant production.

  7. Withdrawal and consumption of water by thermoelectric power plants in the United States, 2010

    USGS Publications Warehouse

    Diehl, Timothy H.; Harris, Melissa A.

    2014-01-01

    An analysis of 2005 and 2010 EIA-reported water use indicated that withdrawal and consumption declined 18 percent and 34 percent, respectively. Alternative water types (types other than freshwater) accounted for approximately 25 percent of all withdrawals in 2010, most of which occurred at plants with once-through cooling systems using saline and brackish tidal waters. Differences among withdrawal and consumption coefficients based on EIA-reported water use for 2005 and 2010 and heat-budget model results for 2010 reveal opportunities for improving consistency and accuracy of reporting of water-use information at the plant scale.

  8. Fate of mercury in tree litter during decomposition

    NASA Astrophysics Data System (ADS)

    Pokharel, A. K.; Obrist, D.

    2011-09-01

    We performed a controlled laboratory litter incubation study to assess changes in dry mass, carbon (C) mass and concentration, mercury (Hg) mass and concentration, and stoichiometric relations between elements during decomposition. Twenty-five surface litter samples each, collected from four forest stands, were placed in incubation jars open to the atmosphere, and were harvested sequentially at 0, 3, 6, 12, and 18 months. Using a mass balance approach, we observed significant mass losses of Hg during decomposition (5 to 23 % of initial mass after 18 months), which we attribute to gaseous losses of Hg to the atmosphere through a gas-permeable filter covering incubation jars. Percentage mass losses of Hg generally were less than observed dry mass and C mass losses (48 to 63 % Hg loss per unit dry mass loss), although one litter type showed similar losses. A field control study using the same litter types exposed at the original collection locations for one year showed that field litter samples were enriched in Hg concentrations by 8 to 64 % compared to samples incubated for the same time period in the laboratory, indicating strong additional sorption of Hg in the field likely from atmospheric deposition. Solubility of Hg, assessed by exposure of litter to water upon harvest, was very low (<0.22 ng Hg g-1 dry mass) and decreased with increasing stage of decomposition for all litter types. Our results indicate potentially large gaseous emissions, or re-emissions, of Hg originally associated with plant litter upon decomposition. Results also suggest that Hg accumulation in litter and surface layers in the field is driven mainly by additional sorption of Hg, with minor contributions from "internal" accumulation due to preferential loss of C over Hg. Litter types showed highly species-specific differences in Hg levels during decomposition suggesting that emissions, retention, and sorption of Hg are dependent on litter type.

  9. Fate of mercury in tree litter during decomposition

    NASA Astrophysics Data System (ADS)

    Pokharel, A. K.; Obrist, D.

    2011-03-01

    We performed a controlled laboratory litter incubation study to assess changes in dry mass, carbon (C) mass and concentration, mercury (Hg) mass and concentration, and stoichiometric relations between elements during decomposition. Twenty-five surface litter samples each, collected from four forest stands, were placed in incubation jars open to the atmosphere, and were harvested sequentially at 0, 3, 6, 12, and 18 months. Using a mass balance approach, we observed significant mass losses of Hg during decomposition (5 to 23% of initial mass after 18 months), which we attribute to gaseous losses of Hg to the atmosphere through a gas-permeable filter covering incubation jars. Percentage mass losses of Hg generally were less than observed dry mass and C mass losses (48% to 63% Hg loss per unit dry mass loss), although one species showed similar losses. A field control study using the same litter types exposed at the original collection locations for one year showed that field litter samples were enriched in Hg concentrations by 8 to 64% compared to samples incubated for the same time period in the laboratory, indicating strong additional sorption of Hg in the field. Solubility of Hg, assessed by exposure of Hg to water upon harvest, was very low (< 0.22 ng Hg g-1 dry mass) and decreased with increasing stage of decomposition for all litter types. Our results indicate large gaseous emissions, or re-emissions, of Hg originally associated with plant litter upon decomposition. Results also suggest that Hg accumulation in litter and surface layers in the field is driven mainly by sorption of Hg - such as from atmospheric deposition - with minor contributions from "internal" accumulation due to preferential loss of C over Hg. Litter types showed highly species-specific differences in Hg levels during decomposition - suggesting that emissions, retention, and sorption of Hg are dependent on litter type.

  10. Stochastic Modeling of Soil Water and Plant Water Stress Using Cumulant Expansion Theory and Its Application to Climate Change Scenarios

    NASA Astrophysics Data System (ADS)

    Kim, S.; Lee, A.; Keem, M.; Shin, H.

    2009-12-01

    For better understanding of soil water and plant water stress dynamics, a stochastic soil water and plant water stress model will be proposed and applied to climate change impact assessment. The proposed model is derived by using cumulant expansion theory from a stochastic differential equation with stochastic rainfall forcings. This model has the advantage of providing the probabilistic solution in the form of a probability distribution function, from which the ensemble average behavior of the system can be obtained easily. Also, since this model uses only the statistics of rainfall time series, the effect of different climate conditions on the soil water and plant water stress dynamics can be incorporated effectively. The simulation result of soil water confirms that the proposed model can reproduce the observation properly and shows that the soil water behaves with consistent cycle based on the precipitation pattern. In order to understand the impact of climate change on soil water and plant water stress behaviors, the RCM data developed by Korean Meteorological Administration (KMA RCM) and the third GCM by Canadian Centre for Climate Modeling and Analysis(CGCM3) are used with two time periods of 2051~2060 and 2091~2100. With all the simulation results, it can be conclude that the simulation results will be different with what climate change scenario is selected since different climate change model predicts different soil water and plant water stress behaviors. This analysis can be expected as a starting point for better understanding of the effect of soil water on ecosystem dynamics such as climate-soil-vegetation interaction. Figure 1. The evolution of the soil water PDF. The soil water PDFs have two different patterns according to wet season from June to September and dry season from October to May. From such result, it can be inferred that the mechanisms which influence the soil water behavior are different in wet and dry seasons. That is to say, in wet

  11. Dynamic aspects of soil water availability for isohydric plants: Focus on root hydraulic resistances

    NASA Astrophysics Data System (ADS)

    Couvreur, V.; Vanderborght, J.; Draye, X.; Javaux, M.

    2014-11-01

    Soil water availability for plant transpiration is a key concept in agronomy. The objective of this study is to revisit this concept and discuss how it may be affected by processes locally influencing root hydraulic properties. A physical limitation to soil water availability in terms of maximal flow rate available to plant leaves (Qavail) is defined. It is expressed for isohydric plants, in terms of plant-centered variables and properties (the equivalent soil water potential sensed by the plant, ψs eq; the root system equivalent conductance, Krs; and a threshold leaf water potential, ψleaf lim). The resulting limitation to plant transpiration is compared to commonly used empirical stress functions. Similarities suggest that the slope of empirical functions might correspond to the ratio of Krs to the plant potential transpiration rate. The sensitivity of Qavail to local changes of root hydraulic conductances in response to soil matric potential is investigated using model simulations. A decrease of radial conductances when the soil dries induces earlier water stress, but allows maintaining higher night plant water potentials and higher Qavail during the last week of a simulated 1 month drought. In opposition, an increase of radial conductances during soil drying provokes an increase of hydraulic redistribution and Qavail at short term. This study offers a first insight on the effect of dynamic local root hydraulic properties on soil water availability. By better understanding complex interactions between hydraulic processes involved in soil-plant hydrodynamics, better prospects on how root hydraulic traits mitigate plant water stress might be achieved.

  12. Water deficit stress - host plant nutrient accumulations and associations with phytophagous arthropods

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In addition to making otherwise arable regions less, or nonarable, from lack of life-sustaining water, water deficit also affects the extent to which crops are afflicted by arthropod pests. This chapter focuses on the effects of water deficit stress on physical and nutritional aspects of host plants...

  13. Development of a Water Treatment Plant Operation Manual Using an Algorithmic Approach.

    ERIC Educational Resources Information Center

    Counts, Cary A.

    This document describes the steps to be followed in the development of a prescription manual for training of water treatment plant operators. Suggestions on how to prepare both flow and narrative prescriptions are provided for a variety of water treatment systems, including: raw water, flocculation, rapid sand filter, caustic soda feed, alum feed,…

  14. Water Use and Drought Resistance of Turfgrass and Ornamental Landscape Plant Species

    ERIC Educational Resources Information Center

    Domenghini, Jacob Cody

    2012-01-01

    In 2005, turfgrass was estimated to cover approximately 20 million ha of urbanized land. That area is increasing with rapid urbanization, stressing the importance of water conservation in the lawn and landscape industry. Turfgrasses have been identified for replacement by presumably more water-efficient ornamental plant species to conserve water.…

  15. The Utility of Decomposition and Associated Microbial Parameters to Assess Changes in Stream Ecosystems due to Eutrophication

    NASA Astrophysics Data System (ADS)

    Gulis, V.; Ferreira, V. J.; Graca, M. A.

    2005-05-01

    Traditional approaches to assess stream ecosystem health rely on structural parameters, e.g. a variety of biotic indices. The goal of the Europe-wide RivFunction project is to develop methodology that uses functional parameters (e.g. plant litter decomposition) to this end. Here we report on decomposition experiments carried out in Portugal in five pairs of streams that differed in dissolved inorganic nutrients. On average, decomposition rates of alder and oak leaves were 2.8 and 1.4 times higher in high nutrient streams in coarse and fine mesh bags, respectively, than in corresponding reference streams. Breakdown rate correlated better with stream water SRP concentration rather than TIN. Fungal biomass and sporulation rates of aquatic hyphomycetes associated with decomposing leaves were stimulated by higher nutrient levels. Both fungal parameters measured at very early stages of decomposition (e.g. days 7-13) correlated well with overall decomposition rates. Eutrophication had no significant effect on shredder abundances in leaf bags but species richness was higher in disturbed streams. Decomposition is a key functional parameter in streams integrating many other variables and can be useful in assessing stream ecosystem health. We also argue that because decomposition is often controlled by fungal activity, microbial parameters can also be useful in bioassessment.

  16. The effects of temperature on decomposition and allelopathic phytotoxicity of boneseed litter.

    PubMed

    Al Harun, Md Abdullah Yousuf; Johnson, Joshua; Uddin, Md Nazim; Robinson, Randall W

    2015-07-01

    Decomposition of plant litter is a fundamental process in ecosystem function, carbon and nutrient cycling and, by extension, climate change. This study aimed to investigate the role of temperature on the decomposition of water soluble phenolics (WSP), carbon and soil nutrients in conjunction with the phytotoxicity dynamics of Chrysanthemoides monilifera subsp. monilifera (boneseed) litter. Treatments consisted of three factors including decomposition materials (litter alone, litter with soil and soil alone), decomposition periods and temperatures (5-15, 15-25 and 25-35°C (night/day)). Leachates were collected on 0, 5, 10, 20, 40 and 60th days to analyse physico-chemical parameters and phytotoxicity. Water soluble phenolics and dissolved organic carbon (DOC) increased with increasing temperature while nutrients like SO4(-2) and NO3(-1) decreased. Speed of germination, hypocotyl and radical length and weight of Lactuca sativa exposed to leachates were decreased with increasing decomposition temperature. All treatment components had significant effects on these parameters. There had a strong correlation between DOC and WSP, and WSP content of the leachates with radical length of test species. This study identified complex interactivity among temperature, WSP, DOC and soil nutrient dynamics of litter occupied soil and that these factors work together to influence phytotoxicity. PMID:26141872

  17. Interactive effects of water supply and defoliation on photosynthesis, plant water status and growth of Eucalyptus globulus Labill.

    PubMed

    Quentin, A G; O'Grady, A P; Beadle, C L; Mohammed, C; Pinkard, E A

    2012-08-01

    Increased climatic variability, including extended periods of drought stress, may compromise on the health of forest ecosystems. The effects of defoliating pests on plantations may also impact on forest productivity. Interactions between climate signals and pest activity are poorly understood. In this study, we examined the combined effects of reduced water availability and defoliation on maximum photosynthetic rate (A(sat)), stomatal conductance (g(s)), plant water status and growth of Eucalyptus globulus Labill. Field-grown plants were subjected to two water-availability regimes, rain-fed (W-) and irrigated (W+). In the summer of the second year of growth, leaves from 75% of crown length removed from trees in both watering treatments and physiological responses within the canopies were examined. We hypothesized that defoliation would result in improved plant water status providing a mechanistic insight into leaf- and canopy-scale gas-exchange responses. Defoliated trees in the W+ treatment exhibited higher A(sat) and g(s) compared with non-defoliated trees, but these responses were not observed in the W- treatment. In contrast, at the whole-plant scale, maximum rates of transpiration (E(max)) and canopy conductance (G(Cmax)) and soil-to-leaf hydraulic conductance (K(P)) increased in both treatments following defoliation. As a result, plant water status was unaffected by defoliation and trees in the defoliated treatments exhibited homeostasis in this respect. Whole-plant soil-to-leaf hydraulic conductance was strongly correlated with leaf scale g(s) and A(sat) following the defoliation, providing a mechanistic insight into compensatory up-regulation of photosynthesis. Above-ground height and diameter growth were unaffected by defoliation in both water availability treatments, suggesting that plants use a range of responses to compensate for the impacts of defoliation. PMID:22874831

  18. Operating boundaries of full-scale advanced water reuse treatment plants: many lessons learned from pilot plant experience.

    PubMed

    Bele, C; Kumar, Y; Walker, T; Poussade, Y; Zavlanos, V

    2010-01-01

    Three Advanced Water Treatment Plants (AWTP) have recently been built in South East Queensland as part of the Western Corridor Recycled Water Project (WCRWP) producing Purified Recycled Water from secondary treated waste water for the purpose of indirect potable reuse. At Luggage Point, a demonstration plant was primarily operated by the design team for design verification. The investigation program was then extended so that the operating team could investigate possible process optimisation, and operation flexibility. Extending the demonstration plant investigation program enabled monitoring of the long term performance of the microfiltration and reverse osmosis membranes, which did not appear to foul even after more than a year of operation. The investigation primarily identified several ways to optimise the process. It highlighted areas of risk for treated water quality, such as total nitrogen. Ample and rapid swings of salinity from 850 to 3,000 mg/l-TDS were predicted to affect the RO process day-to-day operation and monitoring. Most of the setpoints used for monitoring under HACCP were determined during the pilot plant trials. PMID:20935373

  19. Transport Membrane Condenser for Water and Energy Recovery from Power Plant Flue Gas

    SciTech Connect

    Dexin Wang

    2012-03-31

    The new waste heat and water recovery technology based on a nanoporous ceramic membrane vapor separation mechanism has been developed for power plant flue gas application. The recovered water vapor and its latent heat from the flue gas can increase the power plant boiler efficiency and reduce water consumption. This report describes the development of the Transport Membrane Condenser (TMC) technology in details for power plant flue gas application. The two-stage TMC design can achieve maximum heat and water recovery based on practical power plant flue gas and cooling water stream conditions. And the report includes: Two-stage TMC water and heat recovery system design based on potential host power plant coal fired flue gas conditions; Membrane performance optimization process based on the flue gas conditions, heat sink conditions, and water and heat transport rate requirement; Pilot-Scale Unit design, fabrication and performance validation test results. Laboratory test results showed the TMC system can exact significant amount of vapor and heat from the flue gases. The recovered water has been tested and proved of good quality, and the impact of SO{sub 2} in the flue gas on the membrane has been evaluated. The TMC pilot-scale system has been field tested with a slip stream of flue gas in a power plant to prove its long term real world operation performance. A TMC scale-up design approach has been investigated and an economic analysis of applying the technology has been performed.

  20. Water uptake efficiency of a maize plant - A simulation case study

    NASA Astrophysics Data System (ADS)

    Meunier, Félicien; Leitner, Daniel; Bodner, Gernot; Javaux, Mathieu; Schnepf, Andrea

    2014-05-01

    Water uptake by plant roots is a complex mechanism controlled by biological and physical properties of the soil-plant-atmosphere system and affects a major component of the water cycle, transpiration. This uptake of water by plants is one of the major factors of plant development. Since water uptake occurs at the roots, root architecture and hydraulic properties both play a crucial role in plant productivity. A fundamental understanding of the main processes of water uptake will enable better breeding of drought resistant plants and the improvement of irrigation strategies. In this work we analyzed the differences of root water uptake between idealized genotypes of a plant using mathematical modelling The numerical simulations were performed by the R-SWMS software (Javaux et al., 2008). The model describes 3-D water movement in soil by solving Richard's equation with a sink term representing root uptake. Water flow within the root xylem network and between soil and root is modelled based on water pressure gradients and calculated according to Doussan's model. The sink term is calculated by integration of local uptakes within rooted representative elementary volumes of soil. The plant water demand is described by a boundary condition at the base of the shoot. We compare the water uptake efficiency of three types of root system architectures of a maize plant. Two are actual architectures from genotypes showing significant differences regarding the internodal distance, the root growth rate and the insertion angle of their primary roots. The third one is an ideotype according to Lynch of the maize plant designed to perform better in one dry environment. We generated with RootBox five repetitions of these three root systems with the same total root volume and simulated two drought scenarios at the flowering stage (lack of water at the top or at the bottom of the soil domain). We did these simulations for two distinct distributions of local conductivities of root

  1. New coal plant technologies will demand more water

    SciTech Connect

    Peltier, R.; Shuster, E.; McNemar, A.; Stiegel, G.J.; Murphy, J.

    2008-04-15

    Population shifts, growing electricity demand, and greater competition for water resources have heightened interest in the link between energy and water. The US Energy Information Administration projects a 22% increase in US installed generating capacity by 2030. Of the 259 GE of new capacity expected to have come on-line by then, more than 192 GW will be thermoelectric and thus require some water for cooling. Our challenge will become balancing people's needs for power and for water. 1 ref., 7 figs.

  2. Microbial As(III) Oxidation in Water Treatment Plant Filters

    EPA Science Inventory

    Arsenic exists in two oxidation states in water - arsenite [As(III)] and arsenate [As(V)]. As(III) is relatively mobile in water and difficult to remove by arsenic-removal treatment processes. Source waters that contain As(III) must add a strong oxidant such as free chlorine or p...

  3. Biogeochemistry of uranium in the soil-plant and water-plant systems in an old uranium mine.

    PubMed

    Favas, Paulo J C; Pratas, João; Mitra, Soumita; Sarkar, Santosh Kumar; Venkatachalam, Perumal

    2016-10-15

    The present study highlights the uranium (U) concentrations in water-soil-plant matrices and the efficiency considering a heterogeneous assemblage of terrestrial and aquatic native plant species to act as the biomonitor and phytoremediator for environmental U-contamination in the Sevilha mine (uraniferous region of Beiras, Central Portugal). A total of 53 plant species belonging to 22 families was collected from 24 study sites along with ambient soil and/or water samples. The concentration of U showed wide range of variations in the ambient medium: 7.5 to 557mgkg(-1) for soil and 0.4 to 113μgL(-1) for water. The maximum potential of U accumulation was recorded in roots of the following terrestrial plants: Juncus squarrosus (450mgkg(-1) DW), Carlina corymbosa (181mgkg(-1) DW) and Juncus bufonius (39.9mgkg(-1) DW), followed by the aquatic macrophytes, namely Callitriche stagnalis (55.6mgkg(-1) DW) Lemna minor (53.0mgkg(-1) DW) and Riccia fluitans (50.6mgkg(-1) DW). Accumulation of U in plant tissues exhibited the following decreasing trend: root>leaves>stem>flowers/fruits and this confirms the unique efficiency of roots in accumulating this radionuclide from host soil/sediment (phytostabilization). Overall, the accumulation pattern in the studied aquatic plants (L. minor, R. fluitans, C. stagnalis and Lythrum portula) dominated over most of the terrestrial counterpart. Among terrestrial plants, the higher mean bioconcentration factor (≈1 in roots/rhizomes of C. corymbosa and J. squarrosus) and translocation factor (31 in Andryala integrifolia) were encountered in the representing families Asteraceae and Juncaceae. Hence, these terrestrial plants can be treated as the promising candidates for the development of the phytostabilization or phytoextraction methodologies based on the accumulation, abundance and biomass production. PMID:27314898

  4. Modeling terrestrial carbon and water dynamics across climatic gradients: does plant trait diversity matter?

    PubMed

    Pappas, Christoforos; Fatichi, Simone; Burlando, Paolo

    2016-01-01

    Plant trait diversity in many vegetation models is crudely represented using a discrete classification of a handful of 'plant types' (named plant functional types; PFTs). The parameterization of PFTs reflects mean properties of observed plant traits over broad categories ignoring most of the inter- and intraspecific plant trait variability. Taking advantage of a multivariate leaf-trait distribution (leaf economics spectrum), as well as documented plant drought strategies, we generate an ensemble of hypothetical species with coordinated attributes, rather than using few PFTs. The behavior of these proxy species is tested using a mechanistic ecohydrological model that translates plant traits into plant performance. Simulations are carried out for a range of climates representative of different elevations and wetness conditions in the European Alps. Using this framework we investigate the sensitivity of ecosystem response to plant trait diversity and compare it with the sensitivity to climate variability. Plant trait diversity leads to highly divergent vegetation carbon dynamics (fluxes and pools) and to a lesser extent water fluxes (transpiration). Abiotic variables, such as soil water content and evaporation, are only marginally affected. These results highlight the need for revising the representation of plant attributes in vegetation models. Probabilistic approaches, based on observed multivariate whole-plant trait distributions, provide a viable alternative. PMID:26389742

  5. Water stress preconditioning to improve drought resistance in young apricot plants.

    PubMed

    Ruiz-Sánchez; Domingo; Torrecillas; Pérez-Pastor

    2000-07-28

    The effect of water stress preconditioning was studied in 1-year-old apricot plants (Prunus armeniaca L., cv. Búlida). Plants were submitted to different treatments, T-0 (control treatment) and T-1, drip irrigated daily; T-2 and T-3, irrigated daily at 50% and 25% of T-0, respectively; T-4 and T-5, irrigated to field capacity every 3 and 6 days, respectively. After 30 days, irrigation was withheld for 10 days, maintaining the T-0 treatment irrigated daily. After this period, the plants were re-irrigated to run-off and treated as control treatment. The stomatal closure and epinasty observed in response to water stress represented adaptive mechanisms to drought, allowing the plants to regulate water loss more effectively and prevent leaf heating. A substantial reduction in the irrigation water supplied combined with a high frequency of application (T-3 treatment) promoted plant hardening; the plants enduring drought better, due to their greater osmotic adjustment (0.77 MPa), which prevented severe plant dehydration and leaf abscission. Such a preconditioning treatment may be valuable for young apricot plants in the nursery stage in order to improve their subsequent resistance to drought. A 50% reduction in daily irrigation (T-2 treatment) did not significantly affect either gas exchange rates or leaf turgor, which suggests that water should be applied frequently if deficit irrigation is to be implemented. PMID:10936532

  6. Paraheliotropism can protect water-stressed bean (Phaseolus vulgaris L.) plants against photoinhibition.

    PubMed

    Pastenes, Claudio; Porter, Victor; Baginsky, Cecilia; Horton, Peter; González, Javiera

    2004-12-01

    In order to estimate the importance of leaf movements on photosynthesis in well-watered and water-stressed field grown bean cultivars (Arroz Tuscola (AT), Orfeo INIA (OI), Bayos Titan (BT), and Hallados Dorado (HD)), CO2 assimilation, leaf temperature, and capacity for the maximum quantum yield recovery, measured as Fv/Fm, were assessed. Leaf water potential was lower in water-stressed compared to control plants throughout the day. Water status determined a decrease in the CO2 assimilation and stomatal conductance as light intensity and temperature increased up to maximal intensities at midday. Both parameters were lower in stressed compared to control plants. Even though high light intensity and water-stress induced stomatal closure is regarded as a photoinhibitory condition, the recovery of variable to maximal fluorescence (Fv/Fm) after 30min of darkness was nearly constant in both water regimes. In fact, higher values were observed in OI and AT when under stress. Photochemical and non-photochemical fluorescence quenching resulted in minor changes during the day and were similar between watered and stressed plants. It is concluded that paraheliotropism, present in the four bean cultivars, efficiently protects stressed plants from photoinhibition in the field and helps maintain leaf temperatures far below the ambient temperatures, however, it may also be responsible for low CO2 assimilation rates in watered plants. PMID:15658802

  7. Water balance altered in cucumber plants infected with Fusarium oxysporum f. sp. cucumerinum

    PubMed Central

    Wang, Min; Sun, Yuming; Sun, Guomei; Liu, Xiaokang; Zhai, Luchong; Shen, Qirong; Guo, Shiwei

    2015-01-01

    Fusarium wilt is caused by the infection and growth of the fungus Fusarium oxysporum in the xylem of host plants. The physiological responses of cucumbers that are infected with Fusarium oxysporum f. sp. cucumerinum (FOC) was studied in pot and hydroponic experiments in a greenhouse. The results showed that although water absorption and stem hydraulic conductance decreased markedly in infected plants, large amounts of red ink accumulated in the leaves of infected cucumber plants. The transpiration rate (E) and stomatal conductance (gs) of the infected plants were significantly reduced, but the E/gs was higher than healthy plants. We further found that there was a positive correlation between leaf membrane injury and E/gs, indicating that the leaf cell membrane injury increased the non-stomatal water loss from infected plants. The fusaric acid (FA), which was detected in the infected plant, resulted in damage to the leaf cell membranes and an increase in E/gs, suggesting that FA plays an important role in non-stomatal water loss. In conclusion, leaf cell membrane injury in the soil-borne Fusarium wilt of cucumber plants induced uncontrolled water loss from damaged cells. FA plays a critical role in accelerating the development of Fusarium wilt in cucumber plants. PMID:25579504

  8. Water balance altered in cucumber plants infected with Fusarium oxysporum f. sp. cucumerinum.

    PubMed

    Wang, Min; Sun, Yuming; Sun, Guomei; Liu, Xiaokang; Zhai, Luchong; Shen, Qirong; Guo, Shiwei

    2015-01-01

    Fusarium wilt is caused by the infection and growth of the fungus Fusarium oxysporum in the xylem of host plants. The physiological responses of cucumbers that are infected with Fusarium oxysporum f. sp. cucumerinum (FOC) was studied in pot and hydroponic experiments in a greenhouse. The results showed that although water absorption and stem hydraulic conductance decreased markedly in infected plants, large amounts of red ink accumulated in the leaves of infected cucumber plants. The transpiration rate (E) and stomatal conductance (gs) of the infected plants were significantly reduced, but the E/gs was higher than healthy plants. We further found that there was a positive correlation between leaf membrane injury and E/gs, indicating that the leaf cell membrane injury increased the non-stomatal water loss from infected plants. The fusaric acid (FA), which was detected in the infected plant, resulted in damage to the leaf cell membranes and an increase in E/gs, suggesting that FA plays an important role in non-stomatal water loss. In conclusion, leaf cell membrane injury in the soil-borne Fusarium wilt of cucumber plants induced uncontrolled water loss from damaged cells. FA plays a critical role in accelerating the development of Fusarium wilt in cucumber plants. PMID:25579504

  9. Impacts of Plant Water Use on Streamflow at Daily, Storm, and Event Scales

    NASA Astrophysics Data System (ADS)

    McNamara, J. P.

    2015-12-01

    The science of runoff generation describes the processes by which catchments lose water by drainage during high flow periods. For many ecohydrological problems, however, we are more interested in how water is retained during low flow periods. For example, fish habitat in the relatively dry catchments of the semiarid mountain west depends on how low streamflow is metered through the summer. Additionally, upland plants survive by the soils ability to retain water in opposition to runoff generation. Here, I discuss the impacts of soil water retention and vegetation on low flow in seasonally dry, semiarid catchments. I present evidence showing 1) low flows are getting lower, 2) plants and streams receive water from different co-existing sources, and 3) transpiration perturbs streamflow at daily, storm and seasonal scales. The simultaneous occurrence of points 2 and 3 point to conflict emerging in recent hydrologic literature: How can plants use water that is seemingly disconnected from streams while simultaneously impacting streamflow?

  10. Responses of wetland plants to effluents in water and sediment

    SciTech Connect

    Walsh, G.E.; Weber, D.E.; Nguyen, M.T.; Esry, L.K.

    1991-01-01

    Responses of two wetland vascular plants, Echinochloa crusgalli and Sesbania macrocarpa, exposed to effluents from a coke plant, a pulp mill, a wastewater treatment plant, and the herbicide, hexazinone, were measured in three types of tests: seed germination and early growth, seedling survival and growth in hydroponic culture, and seedling survival and growth in sand and synthetic sediments with clay, silt, and sand, 3, 5, 7.5, or 10% organic contents. There was no effect of effluents or herbicide on germination and survival was affected only by the herbicide. When compared to controls, growth rates were reduced significantly in all tests except for E. crusgalli exposed to effluent from a wastewater treatment plant. There, the effluent stimulated growth in sediments. Increasing concentrations of organic matter in sediments had little effect on toxicity of effluents, but did cause reduced effects of hexazinone.

  11. The Role of Demand Response in Reducing Water-Related Power Plant Vulnerabilities

    NASA Astrophysics Data System (ADS)

    Macknick, J.; Brinkman, G.; Zhou, E.; O'Connell, M.; Newmark, R. L.; Miara, A.; Cohen, S. M.

    2015-12-01

    The electric sector depends on readily available water supplies for reliable and efficient operation. Elevated water temperatures or low water levels can trigger regulatory or plant-level decisions to curtail power generation, which can affect system cost and reliability. In the past decade, dozens of power plants in the U.S. have curtailed generation due to water temperatures and water shortages. Curtailments occur during the summer, when temperatures are highest and there is greatest demand for electricity. Climate change could alter the availability and temperature of water resources, exacerbating these issues. Constructing alternative cooling systems to address vulnerabilities can be capital intensive and can also affect power plant efficiencies. Demand response programs are being implemented by electric system planners and operators to reduce and shift electricity demands from peak usage periods to other times of the day. Demand response programs can also play a role in reducing water-related power sector vulnerabilities during summer months. Traditionally, production cost modeling and demand response analyses do not include water resources. In this effort, we integrate an electricity production cost modeling framework with water-related impacts on power plants in a test system to evaluate the impacts of demand response measures on power system costs and reliability. Specifically, we i) quantify the cost and reliability implications of incorporating water resources into production cost modeling, ii) evaluate the impacts of demand response measures on reducing system costs and vulnerabilities, and iii) consider sensitivity analyses with cooling systems to highlight a range of potential benefits of demand response measures. Impacts from climate change on power plant performance and water resources are discussed. Results provide key insights to policymakers and practitioners for reducing water-related power plant vulnerabilities via lower cost methods.

  12. Toxicity tests of effluents with marsh plants in water and sediment

    SciTech Connect

    Walsh, G.E.; Weber, D.E.; Simon, T.L.; Brashers, L.K.

    1991-01-01

    Methods are described for toxicity testing of water and sediment with two varieties of the freshwater marsh plant Echinochloa crusgalli (Linneaus) Palisot de Beauvois (Poaceae), and complex effluents. Two tests are described: a seed germination and early seedling growth test in water, and a survival and seedling growth test in natural and synthetic sediments. Effects of effluents from a sewage treatment plant, tannery, textile mill, pulp and paper mill, coking plant and sewage treatment plant included inhibition of germination, chlorophyll synthesis and growth. The tests with rooted marsh plants were sensitive to pollutants and detected toxicity of a range of pollutants in water and sediment. Synthetic sediments similar to natural sediments allowed toxicity tests to be done under carefully controlled conditions of particle size distribution, organic content, pH, electrode potential (Eh) and cation exchange capacity (CEC).

  13. IMPACTS OF COAL-FIRED POWER PLANTS ON LOCAL GROUND-WATER SYSTEMS: WISCONSIN POWER PLANT IMPACT STUDY

    EPA Science Inventory

    Quantitative techniques for simulating the impacts of a coal-fired power plant on the ground-water system of a river flood-plain wetland were developed and tested. Effects related to the construction and operation of the cooling lake and ashpit had the greatest impact. Ground-wat...

  14. A co-beneficial system using aquatic plants: bioethanol production from free-floating aquatic plants used for water purification.

    PubMed

    Soda, S; Mishima, D; Inoue, D; Ike, M

    2013-01-01

    A co-beneficial system using constructed wetlands (CWs) planted with aquatic plants is proposed for bioethanol production and nutrient removal from wastewater. The potential for bioethanol production from aquatic plant biomass was experimentally evaluated. Water hyacinth and water lettuce were selected because of their high growth rates and easy harvestability attributable to their free-floating vegetation form. The alkaline/oxidative pretreatment was selected for improving enzymatic hydrolysis of the aquatic plants. Ethanol was produced with yields of 0.14-0.17 g-ethanol/ g-biomass in a simultaneous saccharification and fermentation mode using a recombinant Escherichia coli strain or a typical yeast strain Saccharomyces cerevisiae. Subsequently, the combined benefits of the CWs planted with the aquatic plants for bioethanol production and nutrient removal were theoretically estimated. For treating domestic wastewater at 1,100 m(3)/d, it was inferred that the anoxic-oxic activated sludge process consumes energy at 3,200 MJ/d, whereas the conventional activated sludge process followed by the CW consumes only 1,800 MJ/d with ethanol production at 115 MJ/d. PMID:23752400

  15. [Decomposition of herbaceous species in reservoir riparian region of Three Gorges Reservoir under flooding condition].

    PubMed

    Yuan, Qing-Ye; Xie, Zong-Qiang; Yang, Lin-Sen; Xiong, Gao-Ming; Li, Zhao-Jia; Fan, Da-Yong

    2014-08-01

    A total of 10 annuals and perennials of herbaceous species were investigated in reservoir riparian region of Three Gorges Reservoir. The correlations between the plants' nutrient release rate and the substrate composition and structural matter were studied under flooding condition. The decomposition rates of different species differed substantially, with the maximum of Alternanthera philoxeroides (decomposition rate constant k = 0.0228 d(-1)) and the minimum of Microstegium vimineum (k = 0.0029 d(-1)). There was no significant difference in k between annuals and perennials. There was no significant difference in nitrogen and phosphorus contents between annuals and perennials. Paspalum paspaloides and Bidens pilosa released more nutrients into the water than the other species. A. philoxeroides had a higher potential to release nitrogen while it had little effect on water phosphorus compared with the other species. Total N, P contents in the water were negatively correlated with the plants' decomposition rate, initial C content, C:N ratio, lignin:N ratio, and positively correlated with initial contents of K, Ca and N in plants. PMID:25509072

  16. Impact of storm water runoff on efficiency of the effluent treatment plant - a case study

    SciTech Connect

    Suresh, I.V.; Murthy, M.V.R.L.; Sanghi, S.K.; Yadava, R.N.; Wanganeo, A.

    1996-04-01

    This paper evaluates the impact of storm water runoff on an existing sewage treatment plant situated in an industrial township. Significant dilution effect is observed during the monsoon period (June-September) in the influent and effluent characteristics of sewage. The estimated excess runoff water during these months is mainly due to the rainfall in the region and due to the absence of proper control or design for the collection of storm water, thereby avoiding the discharge of the storm water into the treatment plant. This has resulted in the reduction of BOD, COD, total nitrogen and total phosphorus, thus decreasing the efficiency of gas generation. 7 refs., 5 figs., 5 tabs.

  17. Water management requirements for animal and plant maintenance on the Space Station

    NASA Technical Reports Server (NTRS)

    Johnson, C. C.; Rasmussen, D.; Curran, G.

    1987-01-01

    Long-duration Space Station experiments that use animals and plants as test specimens will require increased automation and advanced technologies for water management in order to free scientist-astronauts from routine but time-consuming housekeeping tasks. The three areas that have been identified as requiring water management and that are discusseed are: (1) drinking water and humidity condensate of the animals, (2) nutrient solution and transpired water of the plants, and (3) habitat cleaning methods. Automation potential, technology assessment, crew time savings, and resupply penalties are also discussed.

  18. COMETABOLISM OF TRIHALOMETHANES BY NITRIFYING BIOFILTERS UNDER DRINKING WATER TREATMENT PLANT CONDITIONS

    EPA Science Inventory

    EPA Identifier: FP916412
    Title: Cometabolism of Trihalomethanes by Nitrifying Biofilters Under Drinking Water Treatment Plant Conditions
    Fellow (Principal Investigator): David G. Wahman
    Institution: University of Texas at Austin
    EPA ...

  19. Water Treatment Plant Sludges--An Update of the State of the Art: Part 2.

    ERIC Educational Resources Information Center

    American Water Works Association Journal, 1978

    1978-01-01

    This report outlines the state of the art with respect to nonmechanical and mechanical methods of dewatering water treatment plant sludge, ultimate solids disposal, and research and development needs. (CS)

  20. Direct recycling of human hygiene water into hydroponic plant growth systems.

    PubMed

    Loader, C A; Garland, J L; Levine, L H; Cook, K L; Mackowiak, C L; Vivenzio, H R

    1999-01-01

    Direct recycling of gray water (human hygiene water) through plant production systems would reduce the need for additional space, mass, and energy for water reclamation in Advanced Life Support (ALS) systems. A plant production system designed to produce 25% of crew food needs could theoretically purify enough water through transpiration for 100% of crew water requirements. This scenario was tested through additions of shower and laundry water to recirculating hydroponic systems containing either wheat or soybean. Surfactant (Igepon TC-42) did not accumulate in the systems, and both the rate of surfactant disappearance and the proportion of Igepon-degrading microorganisms on the plant roots increased with time. A mechanism of surfactant degradation via the microbially ally mediated hydrolysis of the amide linkage and subsequent breakdown of fatty acid components is proposed. Fecal coliforms present in the human gray water were not detectable on the plant roots, indicating that human-associated microorganisms do not grow in the system. Overall plant growth was unaffected by gray water additions, although preliminary evidence suggests that reproduction may be inhibited. PMID:11542241

  1. Electrophysiological assessment of water stress in fruit-bearing woody plants.

    PubMed

    Ríos-Rojas, Liliana; Tapia, Franco; Gurovich, Luis A

    2014-06-15

    Development and evaluation of a real-time plant water stress sensor, based on the electrophysiological behavior of fruit-bearing woody plants is presented. Continuous electric potentials are measured in tree trunks for different irrigation schedules, inducing variable water stress conditions; results are discussed in relation to soil water content and micro-atmospheric evaporative demand, determined continuously by conventional sensors, correlating this information with tree electric potential measurements. Systematic and differentiable patterns of electric potentials for water-stressed and no-stressed trees in 2 fruit species are presented. Early detection and recovery dynamics of water stress conditions can also be monitored with these electrophysiology sensors, which enable continuous and non-destructive measurements for efficient irrigation scheduling throughout the year. The experiment is developed under controlled conditions, in Faraday cages located at a greenhouse area, both in Persea americana and Prunus domestica plants. Soil moisture evolution is controlled using capacitance sensors and solar radiation, temperature, relative humidity, wind intensity and direction are continuously registered with accurate weather sensors, in a micro-agrometeorological automatic station located at the experimental site. The electrophysiological sensor has two stainless steel electrodes (measuring/reference), inserted on the stem; a high precision Keithley 2701 digital multimeter is used to measure plant electrical signals; an algorithm written in MatLab(®), allows correlating the signal to environmental variables. An electric cyclic behavior is observed (circadian cycle) in the experimental plants. For non-irrigated plants, the electrical signal shows a time positive slope and then, a negative slope after restarting irrigation throughout a rather extended recovery process, before reaching a stable electrical signal with zero slope. Well-watered plants presented a

  2. Influence of temperature and process technology on the occurrence of Aeromonas species and hygienic indicator organisms in drinking water production plants.

    PubMed

    Kersters, I; Van Vooren, L; Huys, G; Janssen, P; Kersters, K; Verstraet, W

    1995-09-01

    The occurrence of Aeromonas spp. and hygienic indicator organisms in raw and treated waters of five drinking water production plants in Flanders (Belgium) was surveyed over a period of 17 months. Aeromonads were isolated on ampicillin-dextrin agar (ADA) and further identified by gas-liquid chromatographic analysis of their cellular fatty acid methyl ester (FAME) content. ADA medium was found to be highly specific for the enumeration of Aeromonas spp. In general, Aeromonas counts were very low in untreated groundwater but numbered 10(4)-10(6) colony-forming units per liter in open storage reservoirs for surface water. Aeromonas spp. were seasonally distributed with maximal densities occurring during the summer. The ecology of Aeromonas in the different waters was studied in relation to the physical, chemical, and microbiological water characteristics. Strongly positive correlations were observed between Aeromonas densities and heterotrophic plate counts, whereas a clearly negative relationship was found with dissolved oxygen. On average, 99.7% of the aeromonads were removed by flocculation-decantation followed by breakpoint chlorination, whereas 98.9% were removed by slow sand filtration. Flocculation-decantation without breakpoint chlorination did not reduce the microbial numbers. At three of four drinking water production plants tested, rapid sand filtration decreased the number of aeromonads and hygienic indicator organisms. At one plant, however, the numbers of Aeromonas and hygienic indicator organisms were high in the sand filter effluents. Increased numbers of aeromonads were also counted in the effluent of the activated carbon filters. Hence, inactivation of Aeromonas spp. by the current process technology appears not sufficient to exclude postchlorination. The survival of aeromonads in certain filter systems may be due to the growth of these bacteria on biodegradable organic material, provided by the decomposition from bacteria, algae, or other sources

  3. The impact of extreme precipitation on plant growth and water relations

    NASA Astrophysics Data System (ADS)

    Zeppel, M.; Lehmann, C.; Lewis, J. D.; Medlyn, B. E.

    2012-12-01

    Background The global hydrological cycle is predicted to become more intense, or extreme in