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Sample records for floodplains affect structure

  1. How does floodplain width affect floodplain river ecology? A preliminary exploration using simulations

    NASA Astrophysics Data System (ADS)

    Power, Mary E.; Parker, Gary; Dietrich, William E.; Sun, Adrian

    1995-09-01

    Hydraulic food chain models allow us to explore the linkages of river discharge regimes and river-floodplain morphology to the structure and dynamics of modeled food webs. Physical conditions (e.g. depth, width, velocity) that vary with river discharge affect the performance (birth, growth, feeding, movement, or death rates) of organisms or trophic groups. Their performances in turn affect their impacts on food webs and ecosystems in channel and floodplain habitats. Here we explore the impact of floodplain width (modeled as 1 ×, 10× and 40× the channel width) on a food web with two energy sources (detritus and vegetation), invertebrates that consume these, a size structured fish population which consumes invertebrates and in which larger fish cannibalize small fish, and birds which feed on large fish. Hydraulic linkages to trophic dynamics are assumed to be mediated in three ways: birds feed efficiently only in shallow water; plant carrying capacity varies non-linearly with water velocity, and mobile and drifting organisms are diluted and concentrated with spillover of river discharge to the floodplain, and its reconfinement to the channel. Aspects of this model are based on field observations of Junk and Bailey from the Amazon, of Sparks from the Mississippi, and on our observations of the Fly River in Papua New Guinea. The model produced several counter-intuitive results. Biomass of invertebrates and fish increased with floodplain width, but much more rapidly from 1 × to 10 × floodplains than from 10 × to 40 × floodplains. For birds, maximum biomass occurred on the 10× floodplain. Initially high bird biomass on the 40 × floodplain declined to extinction over time, because although favorable fishing conditions (shallow water) were most prolonged on the widest floodplain, this advantage was more than offset by the greater dilution of prey after spillover. Bird predation on large fish sometimes increased their biomass, by reducing cannibalism and thereby

  2. Loss of Rare Fish Species from Tropical Floodplain Food Webs Affects Community Structure and Ecosystem Multifunctionality in a Mesocosm Experiment

    PubMed Central

    Pendleton, Richard M.; Hoeinghaus, David J.; Gomes, Luiz C.; Agostinho, Angelo A.

    2014-01-01

    Experiments with realistic scenarios of species loss from multitrophic ecosystems may improve insight into how biodiversity affects ecosystem functioning. Using 1000 L mesocoms, we examined effects of nonrandom species loss on community structure and ecosystem functioning of experimental food webs based on multitrophic tropical floodplain lagoon ecosystems. Realistic biodiversity scenarios were developed based on long-term field surveys, and experimental assemblages replicated sequential loss of rare species which occurred across all trophic levels of these complex food webs. Response variables represented multiple components of ecosystem functioning, including nutrient cycling, primary and secondary production, organic matter accumulation and whole ecosystem metabolism. Species richness significantly affected ecosystem function, even after statistically controlling for potentially confounding factors such as total biomass and direct trophic interactions. Overall, loss of rare species was generally associated with lower nutrient concentrations, phytoplankton and zooplankton densities, and whole ecosystem metabolism when compared with more diverse assemblages. This pattern was also observed for overall ecosystem multifunctionality, a combined metric representing the ability of an ecosystem to simultaneously maintain multiple functions. One key exception was attributed to time-dependent effects of intraguild predation, which initially increased values for most ecosystem response variables, but resulted in decreases over time likely due to reduced nutrient remineralization by surviving predators. At the same time, loss of species did not result in strong trophic cascades, possibly a result of compensation and complexity of these multitrophic ecosystems along with a dominance of bottom-up effects. Our results indicate that although rare species may comprise minor components of communities, their loss can have profound ecosystem consequences across multiple trophic

  3. Loss of rare fish species from tropical floodplain food webs affects community structure and ecosystem multifunctionality in a mesocosm experiment.

    PubMed

    Pendleton, Richard M; Hoeinghaus, David J; Gomes, Luiz C; Agostinho, Angelo A

    2014-01-01

    Experiments with realistic scenarios of species loss from multitrophic ecosystems may improve insight into how biodiversity affects ecosystem functioning. Using 1000 L mesocoms, we examined effects of nonrandom species loss on community structure and ecosystem functioning of experimental food webs based on multitrophic tropical floodplain lagoon ecosystems. Realistic biodiversity scenarios were developed based on long-term field surveys, and experimental assemblages replicated sequential loss of rare species which occurred across all trophic levels of these complex food webs. Response variables represented multiple components of ecosystem functioning, including nutrient cycling, primary and secondary production, organic matter accumulation and whole ecosystem metabolism. Species richness significantly affected ecosystem function, even after statistically controlling for potentially confounding factors such as total biomass and direct trophic interactions. Overall, loss of rare species was generally associated with lower nutrient concentrations, phytoplankton and zooplankton densities, and whole ecosystem metabolism when compared with more diverse assemblages. This pattern was also observed for overall ecosystem multifunctionality, a combined metric representing the ability of an ecosystem to simultaneously maintain multiple functions. One key exception was attributed to time-dependent effects of intraguild predation, which initially increased values for most ecosystem response variables, but resulted in decreases over time likely due to reduced nutrient remineralization by surviving predators. At the same time, loss of species did not result in strong trophic cascades, possibly a result of compensation and complexity of these multitrophic ecosystems along with a dominance of bottom-up effects. Our results indicate that although rare species may comprise minor components of communities, their loss can have profound ecosystem consequences across multiple trophic

  4. Do high levels of diffuse and chronic metal pollution in sediments of Rhine and Meuse floodplains affect structure and functioning of terrestrial ecosystems?

    PubMed

    Rozema, Jelte; Notten, Martje J M; Aerts, Rien; van Gestel, Cornelis A M; Hobbelen, Peter H F; Hamers, Timo H M

    2008-12-01

    This paper (re)considers the question if chronic and diffuse heavy metal pollution (cadmium, copper, lead and zinc) affects the structure and functioning of terrestrial ecosystems of Biesbosch National Park, the floodplain area of rivers Meuse and Rhine. To reach this aim, we integrated the results of three projects on: 1. the origin, transfer and effects of heavy metals in a soil-plant-snail food chain; 2. the impact of bioavailability on effects of heavy metals on the structure and functioning of detritivorous communities; 3. the risk assessment of heavy metals for an herbivorous and a carnivorous small mammal food chain. Metal pollution levels of the Biesbosch floodplain soils are high. The bioavailability of metals in the soils is low, causing low metal levels in plant leaves. Despite this, metal concentrations in soil dwelling detritivores and in land snails at polluted locations are elevated in comparison to animals from 'non-polluted' reference sites. However, no adverse effects on ecosystem structure (species richness, density, biomass) and functioning (litter decomposition, leaf consumption, reproduction) have been found. Sediment metal pollution may pose a risk to the carnivorous small mammal food chain, in which earthworms with elevated metal concentrations are eaten by the common shrew. Additional measurements near an active metal smelter, however, show reduced leaf consumption rates and reduced reproduction by terrestrial snails, reflecting elevated metal bioavailability at this site. Since future management may also comprise reintroduction of tidal action in the Biesbosch area, changes in metal bioavailability, and as a consequence future ecosystem effects, cannot be excluded.

  5. Do high levels of diffuse and chronic metal pollution in sediments of Rhine and Meuse floodplains affect structure and functioning of terrestrial ecosystems?

    PubMed

    Rozema, Jelte; Notten, Martje J M; Aerts, Rien; van Gestel, Cornelis A M; Hobbelen, Peter H F; Hamers, Timo H M

    2008-12-01

    This paper (re)considers the question if chronic and diffuse heavy metal pollution (cadmium, copper, lead and zinc) affects the structure and functioning of terrestrial ecosystems of Biesbosch National Park, the floodplain area of rivers Meuse and Rhine. To reach this aim, we integrated the results of three projects on: 1. the origin, transfer and effects of heavy metals in a soil-plant-snail food chain; 2. the impact of bioavailability on effects of heavy metals on the structure and functioning of detritivorous communities; 3. the risk assessment of heavy metals for an herbivorous and a carnivorous small mammal food chain. Metal pollution levels of the Biesbosch floodplain soils are high. The bioavailability of metals in the soils is low, causing low metal levels in plant leaves. Despite this, metal concentrations in soil dwelling detritivores and in land snails at polluted locations are elevated in comparison to animals from 'non-polluted' reference sites. However, no adverse effects on ecosystem structure (species richness, density, biomass) and functioning (litter decomposition, leaf consumption, reproduction) have been found. Sediment metal pollution may pose a risk to the carnivorous small mammal food chain, in which earthworms with elevated metal concentrations are eaten by the common shrew. Additional measurements near an active metal smelter, however, show reduced leaf consumption rates and reduced reproduction by terrestrial snails, reflecting elevated metal bioavailability at this site. Since future management may also comprise reintroduction of tidal action in the Biesbosch area, changes in metal bioavailability, and as a consequence future ecosystem effects, cannot be excluded. PMID:18707753

  6. Reoccupation of floodplains by rivers and its relation to the age structure of floodplain vegetation

    USGS Publications Warehouse

    Konrad, Christopher P.

    2012-01-01

    River channel dynamics over many decades provide a physical control on the age structure of floodplain vegetation as a river occupies and abandons locations. Floodplain reoccupation by a river, in particular, determines the interval of time during which vegetation can establish and mature. A general framework for analyzing floodplain reoccupation and a time series model are developed and applied to five alluvial rivers in the United States. Channel dynamics in these rivers demonstrate time-scale dependence with short-term oscillation in active channel area in response to floods and subsequent vegetation growth and progressive lateral movement that accounts for much of the cumulative area occupied by the rivers over decades. Rivers preferentially reoccupy locations recently abandoned causing a decreasing probability of reoccupation with time since abandonment. For a typical case, a river is 10 times more likely to reoccupy an area it abandoned in the past decade than it is to reoccupy an area it abandoned 30 yrs ago. The decreasing probability of reoccupation over time is consistent with observations of persistent stands of late seral stage floodplain forest. A power function provides a robust approach for estimating the cumulative area occupied by a river and the age structure of riparian forests resulting from a specific historical sequence of streamflow in comparison to either linear or exponential alternatives.

  7. Linking river, floodplain, and vadose zone hydrology to improve restoration of a coastal river affected by saltwater intrusion.

    PubMed

    Kaplan, D; Muñoz-Carpena, R; Wan, Y; Hedgepeth, M; Zheng, F; Roberts, R; Rossmanith, R

    2010-01-01

    Floodplain forests provide unique ecological structure and function, which are often degraded or lost when watershed hydrology is modified. Restoration of damaged ecosystems requires an understanding of surface water, groundwater, and vadose (unsaturated) zone hydrology in the floodplain. Soil moisture and porewater salinity are of particular importance for seed germination and seedling survival in systems affected by saltwater intrusion but are difficult to monitor and often overlooked. This study contributes to the understanding of floodplain hydrology in one of the last bald cypress [Taxodium distichum (L.) Rich.] floodplain swamps in southeast Florida. We investigated soil moisture and porewater salinity dynamics in the floodplain of the Loxahatchee River, where reduced freshwater flow has led to saltwater intrusion and a transition to salt-tolerant, mangrove-dominated communities. Twenty-four dielectric probes measuring soil moisture and porewater salinity every 30 min were installed along two transects-one in an upstream, freshwater location and one in a downstream tidal area. Complemented by surface water, groundwater, and meteorological data, these unique 4-yr datasets quantified the spatial variability and temporal dynamics of vadose zone hydrology. Results showed that soil moisture can be closely predicted based on river stage and topographic elevation (overall Nash-Sutcliffe coefficient of efficiency = 0.83). Porewater salinity rarely exceeded tolerance thresholds (0.3125 S m(-1)) for bald cypress upstream but did so in some downstream areas. This provided an explanation for observed vegetation changes that both surface water and groundwater salinity failed to explain. The results offer a methodological and analytical framework for floodplain monitoring in locations where restoration success depends on vadose zone hydrology and provide relationships for evaluating proposed restoration and management scenarios for the Loxahatchee River.

  8. Sediment management and renewability of floodplain clay for structural ceramics

    NASA Astrophysics Data System (ADS)

    van der Meulen, M. J.; Wiersma, A. P.; Middelkoop, H.; van der Perk, M.; Bakker, M.; Maljers, D.; Hobo, N.; Makaske, B.

    2009-04-01

    The Netherlands have vast resources of clay that are exploited for the fabrication of structural ceramic products such as bricks and roof tiles. The extraction of clay creates land surface lowerings of about 1.5 m, of which the majority are located in the embanked floodplains of the rivers Rhine and Meuse. At these surface lowerings, clay is replenished within several decades. This study explores to which extent the clay can be regarded as a renewable resource, with potential for sustainable use. For this purpose, first the current and past clay consumption is calculated. Subsequently, clay deposition in the floodplains is estimated from literature data on clay accumulation using sediment traps, heavy metal and radionuclide distribution in soil profiles, and from morphological modelling studies. These estimates of clay-deposition and consumption are then compared following three approaches that consider various temporal and spatial scales of clay deposition. This allows us to establish the extent to which man determines sedimentary processes in the Dutch floodplains. Consequently, using the sediment response to the land surface lowering resulting from clay extraction, we explore sediment management options for the Dutch Rhine and Meuse. Altogether we argue that clay has been, probably is, and certainly can be managed as a renewable mineral resource.

  9. Exposure of wood in floodplains affects its chemical quality and its subsequent breakdown in streams.

    PubMed

    del Campo, Rubén; Gómez, Rosa

    2016-02-01

    In stream ecosystems, coarse organic matter from the riparian vegetation, a key food resource, is often retained in the floodplains before reaching the channel. During floodplain exposure, organic matter can be affected by abiotic and biotic processes ("preconditioning"), which alter its quality and affect its subsequent decomposition in streams. We analyzed the effect of floodplain preconditioning on wood quality (lignin, C, N, P, K, among others), and its subsequent aquatic breakdown, paying special attention to microbial activity. We simulated preconditioned standard wooden sticks on one arid stream floodplain for 3 and 4 months, and then monitored their breakdown in three different streams, together with control (non-preconditioned) sticks. Preconditioning reduced lignin mass and C:N and lignin:N ratios, caused the leaching of soluble nutrients such as P and K, as well as N immobilization by microbes. These changes enhanced the breakdown of wood in the first week of immersion, but had no effect on breakdown rates after 4 months of incubation in the streams, although N immobilization was diminished. Our results suggest that terrestrial preconditioning could alter the role of wood as a long-lasting nutrients and energy source for freshwater ecosystem.

  10. Exposure of wood in floodplains affects its chemical quality and its subsequent breakdown in streams.

    PubMed

    del Campo, Rubén; Gómez, Rosa

    2016-02-01

    In stream ecosystems, coarse organic matter from the riparian vegetation, a key food resource, is often retained in the floodplains before reaching the channel. During floodplain exposure, organic matter can be affected by abiotic and biotic processes ("preconditioning"), which alter its quality and affect its subsequent decomposition in streams. We analyzed the effect of floodplain preconditioning on wood quality (lignin, C, N, P, K, among others), and its subsequent aquatic breakdown, paying special attention to microbial activity. We simulated preconditioned standard wooden sticks on one arid stream floodplain for 3 and 4 months, and then monitored their breakdown in three different streams, together with control (non-preconditioned) sticks. Preconditioning reduced lignin mass and C:N and lignin:N ratios, caused the leaching of soluble nutrients such as P and K, as well as N immobilization by microbes. These changes enhanced the breakdown of wood in the first week of immersion, but had no effect on breakdown rates after 4 months of incubation in the streams, although N immobilization was diminished. Our results suggest that terrestrial preconditioning could alter the role of wood as a long-lasting nutrients and energy source for freshwater ecosystem. PMID:26613519

  11. Hydrologic linkages drive spatial structuring of bacterial assemblages and functioning in alpine floodplains.

    PubMed

    Freimann, Remo; Bürgmann, Helmut; Findlay, Stuart E G; Robinson, Christopher T

    2015-01-01

    Microbial community assembly and microbial functions are affected by a number of different but coupled drivers such as local habitat characteristics, dispersal rates, and species interactions. In groundwater systems, hydrological flow can introduce spatial structure and directional dependencies among these drivers. We examined the importance of hydrology in structuring bacterial communities and their function within two alpine floodplains during different hydrological states. Piezometers were installed in stream sediments and surrounding riparian zones to assess hydrological flows and also were used as incubation chambers to examine bacterial community structures and enzymatic functions along hydrological flow paths. Spatial eigenvector models in conjunction with models based on physico-chemical groundwater characteristics were used to evaluate the importance of hydrologically-driven processes influencing bacterial assemblages and their enzymatic activities. Our results suggest a strong influence (up to 40% explained variation) of hydrological connectivity on enzymatic activities. The effect of hydrology on bacterial community structure was considerably less strong, suggesting that assemblages demonstrate large functional plasticity/redundancy. Effect size varied between hydrological periods but flow-related mechanisms always had the most power in explaining both bacterial structure and functioning. Changes in hydrology should be considered in models predicting ecosystem functioning and integrated into ecosystem management strategies for floodplains.

  12. Hydrologic linkages drive spatial structuring of bacterial assemblages and functioning in alpine floodplains

    PubMed Central

    Freimann, Remo; Bürgmann, Helmut; Findlay, Stuart E. G.; Robinson, Christopher T.

    2015-01-01

    Microbial community assembly and microbial functions are affected by a number of different but coupled drivers such as local habitat characteristics, dispersal rates, and species interactions. In groundwater systems, hydrological flow can introduce spatial structure and directional dependencies among these drivers. We examined the importance of hydrology in structuring bacterial communities and their function within two alpine floodplains during different hydrological states. Piezometers were installed in stream sediments and surrounding riparian zones to assess hydrological flows and also were used as incubation chambers to examine bacterial community structures and enzymatic functions along hydrological flow paths. Spatial eigenvector models in conjunction with models based on physico-chemical groundwater characteristics were used to evaluate the importance of hydrologically-driven processes influencing bacterial assemblages and their enzymatic activities. Our results suggest a strong influence (up to 40% explained variation) of hydrological connectivity on enzymatic activities. The effect of hydrology on bacterial community structure was considerably less strong, suggesting that assemblages demonstrate large functional plasticity/redundancy. Effect size varied between hydrological periods but flow-related mechanisms always had the most power in explaining both bacterial structure and functioning. Changes in hydrology should be considered in models predicting ecosystem functioning and integrated into ecosystem management strategies for floodplains. PMID:26579113

  13. Hydrologic linkages drive spatial structuring of bacterial assemblages and functioning in alpine floodplains.

    PubMed

    Freimann, Remo; Bürgmann, Helmut; Findlay, Stuart E G; Robinson, Christopher T

    2015-01-01

    Microbial community assembly and microbial functions are affected by a number of different but coupled drivers such as local habitat characteristics, dispersal rates, and species interactions. In groundwater systems, hydrological flow can introduce spatial structure and directional dependencies among these drivers. We examined the importance of hydrology in structuring bacterial communities and their function within two alpine floodplains during different hydrological states. Piezometers were installed in stream sediments and surrounding riparian zones to assess hydrological flows and also were used as incubation chambers to examine bacterial community structures and enzymatic functions along hydrological flow paths. Spatial eigenvector models in conjunction with models based on physico-chemical groundwater characteristics were used to evaluate the importance of hydrologically-driven processes influencing bacterial assemblages and their enzymatic activities. Our results suggest a strong influence (up to 40% explained variation) of hydrological connectivity on enzymatic activities. The effect of hydrology on bacterial community structure was considerably less strong, suggesting that assemblages demonstrate large functional plasticity/redundancy. Effect size varied between hydrological periods but flow-related mechanisms always had the most power in explaining both bacterial structure and functioning. Changes in hydrology should be considered in models predicting ecosystem functioning and integrated into ecosystem management strategies for floodplains. PMID:26579113

  14. Do weirs affect the physical and geochemical mobility of toxic metals in mining-impacted floodplain sediments?

    NASA Astrophysics Data System (ADS)

    Bulcock, Amelia; Coleman, Alexandra; Whitfield, Elizabeth; Andres Lopez-Tarazon, Jose; Byrne, Patrick; Whitfield, Greg

    2015-04-01

    Weirs are common river structures designed to modify river channel hydraulics and hydrology for purposes of navigation, flood defence, irrigation and hydrometry. By design, weirs constrain natural flow processes and affect sediment flux and river channel forms leading to homogenous river habitats and reduced biodiversity. The recent movement towards catchment-wide river restoration, driven by the EU Water Framework Directive, has recognised weirs as a barrier to good ecological status. However, the removal of weirs to achieve more 'natural' river channels and flow processes is inevitably followed by a period of adjustment to the new flow regime and sediment flux. This period of adjustment can have knock-on effects that may increase flood risk, sedimentation and erosion until the river reaches a state of geomorphological equilibrium. Many catchments in the UK contain a legacy of toxic metals in floodplain sediments due to historic metal mining activities. The consequences of weir removal in these catchments may be to introduce 'stored' mine wastes into the river system with severe implications for water quality and biodiversity. The purpose of this study is to investigate the potential impact of a weir on the physical and geochemical mobilisation of mine wastes in the formerly mined River Twymyn catchment, Wales. Our initial investigations have shown floodplain and riverbed sediments to be grossly contaminated (up to 15,500 mg/kg Pb) compared to soil from a pre-mining Holocene terrace (180 mg/kg Pb). Geomorphological investigations also suggest that weir removal will re-establish more dynamic river channel processes resulting in lateral migration of the channel and erosion of contaminated floodplain sediments. These data will be used as a baseline for more detailed investigations of the potential impact of weirs on the physical and geochemical mobilisation of contaminated sediments. We have two specific objectives. (1) Geomorphological assessments will use unmanned

  15. Biogeochemical factors affecting mercury methylation rate in two contaminated floodplain soils

    NASA Astrophysics Data System (ADS)

    Frohne, T.; Rinklebe, J.; Langer, U.; Du Laing, G.; Mothes, S.; Wennrich, R.

    2012-01-01

    An automated biogeochemical microcosm system allowing controlled variation of redox potential (EH) in soil suspensions was used to assess the effect of various factors on the mobility of mercury (Hg) as well as on the methylation of Hg in two contaminated floodplain soils with different Hg concentrations (approximately 5 mg Hg kg-1 and >30 mg Hg kg-1). The experiment was conducted under stepwise variation from reducing (approximately -350 mV at pH 5) to oxidizing conditions (approximately 600 mV at pH 5). Results of phospholipid fatty acids (PLFA) analysis indicate the occurrence of sulfate reducing bacteria (SRB) such as Desulfobacter species (10Me16:0, cy17:0, 10Me18:0, cy19:0) or Desulfovibrio species (18:2ω6,9), which are considered to promote Hg methylation. The products of the methylation process are lipophilic, highly toxic methyl mercury species such as the monomethyl mercury ion [MeHg+], which is named as MeHg here. The ln(MeHg/Hgt) ratio is assumed to reflect the net production of monomethyl mercury normalized to total dissolved Hg (Hgt) concentration. This ratio increases with rising dissolved organic carbon (DOC) to Hgt ratio (ln(DOC/Hgt) ratio) (R2 = 0.39, p<0.0001, n= 63) whereas the relation between ln(MeHg/Hgt ratio and lnDOC is weaker (R2 = 0.09; p<0.05; n = 63). In conclusion, the DOC/Hgt ratio might be a more important factor for the Hg net methylation than DOC alone in the current study. Redox variations seem to affect the biogeochemical behavior of dissolved inorganic Hg species and MeHg indirectly through related changes in DOC, sulfur cycle, and microbial community structure whereas EH and pH values, as well as concentration of dissolved Fe3+/Fe2+ and Cl- seem to play subordinate roles in Hg mobilization and methylation under our experimental conditions.

  16. Biogeochemical factors affecting mercury methylation rate in two contaminated floodplain soils

    NASA Astrophysics Data System (ADS)

    Frohne, T.; Rinklebe, J.; Langer, U.; Du Laing, G.; Mothes, S.; Wennrich, R.

    2011-09-01

    An automated biogeochemical microcosm system allowing controlled variation of redox potential (EH) in soil suspensions was used to assess the effect of various factors on the mobility of mercury (Hg) as well as on the methylation of Hg in two contaminated floodplain soils with different Hg concentrations (approximately 5 mg kg-1 Hg and >30 mg kg-1 Hg). The experiment was conducted under stepwise variation from reducing (approximately -350 mV at pH 5) to oxidizing conditions (approximately 600 mV at pH 5). Results of phospholipid fatty acids (PLFA) analysis indicate the occurrence of sulfate reducing bacteria (SRB) such as Desulfobacter species (10me16:0, cy17:0, 10me18:0, cy19:0) or Desulfovibrio species (18:2ω6,9), which are considered to promote Hg methylation. The products of the methylation process are lipophilic, highly toxic methyl mercury species such as the monomethyl mercury ion [MeHg+], which is named as MeHg here. The ln(MeHg/Hgt) ratio is assumed to reflect the net production of monomethyl mercury normalized to total dissolved Hg (Hgt) concentration. This ratio increases with rising dissolved organic carbon (DOC) to Hgt ratio (lnDOC/lnHgt ratio) (R2 = 0.39, p < 0.0001, n = 63) whereas the relation between ln(MeHg/Hgt) ratio and lnDOC is weaker (R2 = 0.09; p < 0.05; n = 63). In conclusion, the DOC/Hgt ratio might be a more important factor for the Hg net methylation than DOC alone in the current study. Redox variations seem to affect the biogeochemical behavior of dissolved inorganic Hg species and MeHg indirectly through related changes in DOC, sulfur cycle, and microbial community structure whereas E,H and pH values, as well as concentration of dissolved Fe,3+/Fe2+ and Cl- seem to play subordinate roles in Hg mobilization and methylation under our experimental conditions.

  17. [Vertical structure of bacterial communities in peats of the Yakhroma River floodplain].

    PubMed

    Dobrovol'skaia, T G; Golovchenko, A V; Pozdniakov, A I

    2007-01-01

    The abundance and taxonomic structure of soil bacterial communities have been studied in different geomorphological parts of the Yakhroma floodplain. It has been found that the numbers of bacteria reach a peak in calcareous peat soil under forest near the floodplain terrace, decreasing to a minimum in soddy alluvial soil near the riverbed. All soils are characterized by the presence of different ecological-trophic bacterial groups capable of peat destruction. Seasonal dynamics of the structure of bacterial communities and, in some soil types, its spatial dynamics accounted for by changes in the botanical structure of peat across its profile have been revealed. All peat soils in the floodplain have high contents of organic matter and neutral pH and, therefore, are favorable biotopes for the development of saprotrophic bacteria. This, in turn, largely accounts for high productivity and stability of this agroecosystem as a whole.

  18. [Vertical structure of bacterial communities in peats of the Yakhroma River floodplain].

    PubMed

    Dobrovol'skaia, T G; Golovchenko, A V; Pozdniakov, A I

    2007-01-01

    The abundance and taxonomic structure of soil bacterial communities have been studied in different geomorphological parts of the Yakhroma floodplain. It has been found that the numbers of bacteria reach a peak in calcareous peat soil under forest near the floodplain terrace, decreasing to a minimum in soddy alluvial soil near the riverbed. All soils are characterized by the presence of different ecological-trophic bacterial groups capable of peat destruction. Seasonal dynamics of the structure of bacterial communities and, in some soil types, its spatial dynamics accounted for by changes in the botanical structure of peat across its profile have been revealed. All peat soils in the floodplain have high contents of organic matter and neutral pH and, therefore, are favorable biotopes for the development of saprotrophic bacteria. This, in turn, largely accounts for high productivity and stability of this agroecosystem as a whole. PMID:18038631

  19. Factors affecting fish biodiversity in floodplain lakes of the Mississippi Alluvial Valley

    USGS Publications Warehouse

    Miranda, Leandro E.; Dembkowski, Daniel J.

    2012-01-01

    River-floodplain ecosystems offer some of the most diverse and dynamic environments in the world. Accordingly, floodplain habitats harbor diverse fish assemblages. Fish biodiversity in floodplain lakes may be influenced by multiple variables operating on disparate scales, and these variables may exhibit a hierarchical organization depending on whether one variable governs another. In this study, we examined the interaction between primary variables descriptive of floodplain lake large-scale features, suites of secondary variables descriptive of water quality and primary productivity, and a set of tertiary variables descriptive of fish biodiversity across a range of floodplain lakes in the Mississippi Alluvial Valley of Mississippi and Arkansas (USA). Lakes varied considerably in their representation of primary, secondary, and tertiary variables. Multivariate direct gradient analyses indicated that lake maximum depth and the percentage of agricultural land surrounding a lake were the most important factors controlling variation in suites of secondary and tertiary variables, followed to a lesser extent by lake surface area. Fish biodiversity was generally greatest in large, deep lakes with lower proportions of watershed agricultural land. Our results may help foster a holistic approach to floodplain lake management and suggest the framework for a feedback model wherein primary variables can be manipulated for conservation and restoration purposes and secondary and tertiary variables can be used to monitor the success of such efforts.

  20. Hierarchy in factors affecting fish biodiversity in floodplain lakes of the Mississippi Alluvial Valley

    USGS Publications Warehouse

    Dembkowski, D.J.; Miranda, L.E.

    2012-01-01

    River-floodplain ecosystems offer some of the most diverse and dynamic environments in the world. Accordingly, floodplain habitats harbor diverse fish assemblages. Fish biodiversity in floodplain lakes may be influenced by multiple variables operating on disparate scales, and these variables may exhibit a hierarchical organization depending on whether one variable governs another. In this study, we examined the interaction between primary variables descriptive of floodplain lake large-scale features, suites of secondary variables descriptive of water quality and primary productivity, and a set of tertiary variables descriptive of fish biodiversity across a range of floodplain lakes in the Mississippi Alluvial Valley of Mississippi and Arkansas (USA). Lakes varied considerably in their representation of primary, secondary, and tertiary variables. Multivariate direct gradient analyses indicated that lake maximum depth and the percentage of agricultural land surrounding a lake were the most important factors controlling variation in suites of secondary and tertiary variables, followed to a lesser extent by lake surface area. Fish biodiversity was generally greatest in large, deep lakes with lower proportions of watershed agricultural land. Our results may help foster a holistic approach to floodplain lake management and suggest the framework for a feedback model wherein primary variables can be manipulated for conservation and restoration purposes and secondary and tertiary variables can be used to monitor the success of such efforts. ?? 2011 Springer Science+Business Media B.V.

  1. Impact of hydrology on methane flux patterns in a permafrost-affected floodplain in Northeast Siberia

    NASA Astrophysics Data System (ADS)

    Kwon, Min Jung; Beulig, Felix; Kuesel, Kirsten; Wildner, Marcus; Heimann, Martin; Zimov, Nikita; Zimov, Sergei; Goeckede, Mathias

    2015-04-01

    A large fraction of organic carbon stored in Arctic permafrost soil is at risk to be decomposed and released to the atmosphere under climate change. Thawing of ice-rich permafrost will re-structure the surface topography, with potentially significant effects on hydrology: water table depth (WTD) of depressed areas will increase, while that of the surrounding area will decrease. Changes in hydrology will trigger modifications in soil and vegetation, e.g. soil temperature, vegetation and microbial community structure. All of these secondary effects will alter carbon cycle processes, with the magnitude and even sign of the net effect yet unknown. The objective of this study is to investigate effects of drainage on methane fluxes in a floodplain of the Kolyma River near Cherskii, Northeast Siberia. The study site is separated into two areas, one that has been drained since 2004, and a nearby reference site. Methane flux was measured for ~16 weeks during summer and early winter of 2013, and summer of 2014. In addition, to separate different methane emission pathways, plant-mediated methane transport (through aerenchyma) as well as the proportion of ebullition were measured in 2014. Vegetation and microbial community structures were investigated and compared. After a decade of drainage history that lowered WTD by about 20cm in the drained area, Eriophorum (cotton grass) that previously dominated have to a large part been replaced by Carex (tussock-forming sedge) and shrub species. While WTD primarily influenced the methane flux rate, this vegetation change indirectly altered the flux as well in a way that sites with Eriophorum emitted more methane. Concerning the microbial community structure, the relative abundance of methanogen and ratio of methanotrophs to methanogens were well correlated with methane flux rates, implying that the methane flux is highly influenced by microorganisms. As a consequence of these changes, in the drained area less amount of methane was

  2. Bacterial structures and ecosystem functions in glaciated floodplains: contemporary states and potential future shifts.

    PubMed

    Freimann, Remo; Bürgmann, Helmut; Findlay, Stuart E G; Robinson, Christopher T

    2013-12-01

    Glaciated alpine floodplains are responding quickly to climate change through shrinking ice masses. Given the expected future changes in their physicochemical environment, we anticipated variable shifts in structure and ecosystem functioning of hyporheic microbial communities in proglacial alpine streams, depending on present community characteristics and landscape structures. We examined microbial structure and functioning during different hydrologic periods in glacial (kryal) streams and, as contrasting systems, groundwater-fed (krenal) streams. Three catchments were chosen to cover an array of landscape features, including interconnected lakes, differences in local geology and degree of deglaciation. Community structure was assessed by automated ribosomal intergenic spacer analysis and microbial function by potential enzyme activities. We found each catchment to contain a distinct bacterial community structure and different degrees of separation in structure and functioning that were linked to the physicochemical properties of the waters within each catchment. Bacterial communities showed high functional plasticity, although achieved by different strategies in each system. Typical kryal communities showed a strong linkage of structure and function that indicated a major prevalence of specialists, whereas krenal sediments were dominated by generalists. With the rapid retreat of glaciers and therefore altered ecohydrological characteristics, lotic microbial structure and functioning are likely to change substantially in proglacial floodplains in the future. The trajectory of these changes will vary depending on contemporary bacterial community characteristics and landscape structures that ultimately determine the sustainability of ecosystem functioning.

  3. Community structure affects behavior.

    PubMed

    Jaenson, C

    1991-06-01

    AID's prevention efforts can benefit from taking into account 5 main aspects (KEPRA) of community structure identified by anthropologists: 1) kinship patterns, 2) economics, 3) politics, 4) religion, and 5) associations. For example, in Uganda among the Basoga and paternal aunt or senga is responsible for female sex education. Such culturally determined patterns need to be targeted in order to enhance education and effectiveness. Economics can reflect differing systems of family support through sexual means. The example given involves a poor family with a teenager in Thailand who exchanges a water buffalo or basic necessity for this daughter's prostitution. Politics must be considered because every society identifies people who have the power to persuade, influence, exchange resources, coerce, or in some way get people to do what is wanted. Utilizing these resources whether its ministers of health, factory owners, or peers is exemplified in the Monterey, Mexico factor floor supervisor and canteen worker introducing to workers the hows and whys of a new AID's education program. His peer status will command more respect than the director with direct authority. Religious beliefs have explanations for causes of sickness or disease, or provide instruction in sex practices. The example given is of a health workers in Uganda discussing AIDS with rural women by saying that we all know that disease and deaths are caused by spells. "But not AIDS - slim. AIDS is different." Associations can help provide educational, economic, and emotional assistance to the AID's effort or families affected.

  4. Structure of the testate amoebae community in different habitats in a neotropical floodplain.

    PubMed

    Lansac-Tôha, F A; Velho, L F M; Costa, D M; Simões, N R; Alves, G M

    2014-02-01

    This study evaluated the differences in composition, abundance and morphology of testate amoebae among different habitats of the same aquatic environment (plankton, aquatic macrophyte and sediment) in the Upper Paraná River floodplain. Triplicate samplings were undertaken monthly at each habitat from April 2007 to March 2008. The structure of the community of testate amoebae was different among the habitats. The species typical for each habitat, according to Indval, were classified by their shell morphology. Arcella species together with Difflugia gramen and Difflugia pseudogramem were more abundant for plankton. Trinema and Phryganella stood out by their abundance and frequency in aquatic macrophytes. Centropyxis was an indicator of sediment. The results indicated a higher frequency of hemispherical and spherical shells in plankton and spherical and elongated shells in aquatic macrophytes. In the sediment, there was a high frequency of elongated species. Our results support the hypothesis that the community of testate amoebae has different structures among the habitats, refuting the idea that the organization of this community in plankton is guided by random events like the resuspension of organisms from the sediment and their displacement from marginal vegetation. PMID:25055100

  5. Spatial structure of floodplain soil radionuclide contamination of the Enisey River near the Krasnoyarsk Mining and Chemical Combine

    NASA Astrophysics Data System (ADS)

    Linnik, V. G.; Brown, J. E.; Potapov, V. N.; Surkov, V. V.

    2012-04-01

    Enisey River floodplain soils were contaminated by technogenic radionuclides arising from operations at the Krasnoyarsk Mining Chemical Combine (KMCC) from 1958 to 1992. The radioecological situtation of the Enisey flood plain landscapes has been formed by the interaction of two factors: (i) characteristics of radionuclide discharges to the aquatic environment, (ii) hydrological regime of the Enisey River. The radionuclide discharge determined the potential extent of contamination, while the river hydrology was responsible for its transport over considerable distances. The erection of the dam of the Krasnoyarsk power station in 1970 changed the hydrological regime of the Enisey River. The water discharge and suspended sediments became uniform in all seasons and extreme floods, extending over high floodplain areas, ceased. The distribution of radioactive contamination within floodplain soils downstream from the KMCC was studied with the objectives of mapping contamination levels and analyzing the spatial structure of radionuclide distributions arising from floodplain formation. Based on a digital elevation model of floodplain landscapes at a strip of KMCC-Strelka the flooded area of the Enisey River was determined. In 1960 to 1970, deposition of contaminated sediments occurred at heights less than 6 m over an area of 99,2 km2, in 1970-1992 the flooded area with a height less than 3,5 m was of 38,2 km2. Since radiocaesium in the Enisey River primarily occurs in a well fixed sediment-associated form it is possible to use the analysis of landscape structure within the floodplain to detect lithologo-geomorphological zones corresponding to a varying degree of 137Cs contamination. Radionuclide contamination was measured using in situ gamma spectrometry and soil sampling undertaken at control points. Maximum 137Cs contamination densities (700 kBq m-2) were found on low- and middle-level floodplains of Beriozovy Island (16 km from the KMCC). The contamination density of 60

  6. [The role of the floodplain gradient in structuring of testate amoebae communities in the Ilych River].

    PubMed

    Mazeĭ, Iu A; Malysheva, E A; Lapteva, E M; Komarov, A A; Taskaeva, A A

    2012-01-01

    Forty-two testate amoebae taxa were identified in alluvial soils of floodplain islands in the Ilych River. Among the pedo- and eurybionts, there were aquatic rhizopods. Along the floodplain transect (willow --> meadow --> deciduous forest --> coniferous forest), the testate amoebae community changed directly. There are spatially homogeneous (low beta-diversity) testacean communities but species rich on the local level (high alpha-diversity) within forests. Within willows and meadows, communities are characterized by low alpha-diversity and high heterogeneity that leads to high gamma-diversity. PMID:22988761

  7. [The role of the floodplain gradient in structuring of testate amoebae communities in the Ilych River].

    PubMed

    Mazeĭ, Iu A; Malysheva, E A; Lapteva, E M; Komarov, A A; Taskaeva, A A

    2012-01-01

    Forty-two testate amoebae taxa were identified in alluvial soils of floodplain islands in the Ilych River. Among the pedo- and eurybionts, there were aquatic rhizopods. Along the floodplain transect (willow --> meadow --> deciduous forest --> coniferous forest), the testate amoebae community changed directly. There are spatially homogeneous (low beta-diversity) testacean communities but species rich on the local level (high alpha-diversity) within forests. Within willows and meadows, communities are characterized by low alpha-diversity and high heterogeneity that leads to high gamma-diversity.

  8. QMRAcatch - faecal microbial quality of water resources in a river-floodplain area affected by urban sources and recreational visitors

    NASA Astrophysics Data System (ADS)

    Derx, Julia; Schijven, Jack; Sommer, Regina; Kirschner, Alexander; Farnleitner, Andreas H.; Blaschke, Alfred Paul

    2016-04-01

    QMRAcatch, a tool to simulate microbial water quality including infection risk assessment, was previously developed and successfully tested at a Danube river site (Schijven et al. 2015). In the tool concentrations of target faecal microorganisms and viruses (TMVs) are computed at a point of interest (PI) along the main river and the floodplain river at daily intervals for a one year period. Even though faecal microbial pathogen concentrations in water resources are usually below the sample limit of detection, this does not ensure, that the water quality complies with a certain required health based target. The aim of this study was therefore to improve the predictability of relevant human pathogenic viruses, i.e. enterovirus and norovirus, in the studied river/floodplain area. This was done by following an innovative calibration strategy based on human-associated microbial source tracking (MST) marker data which were determined following the HF183 TaqMan assay (Green et al. 2011). The MST marker is strongly associated with human faeces and communal sewage, occurring there in numbers by several magnitudes higher than for human enteric pathogens (Mayer et al 2015). The calibrated tool was then evaluated with measured enterovirus concentrations at the PI and in the floodplain river. In the simulation tool the discharges of 5 wastewater treatment plants (WWTPs) were considered with point discharges along a 200 km reach of the Danube river. The MST marker and target virus concentrations at the PI at a certain day were computed based on the concentrations of the previous day, plus the wastewater concentrations times the WWTP discharge divided by the river discharge. A ratio of the river width was also considered, over which the MST marker and virus particles have fully mixed with river water. In the tool, the excrements from recreational visitors frequenting the floodplain area every day were assumed to be homogeneously distributed in the area. A binomial distributed

  9. QMRAcatch - faecal microbial quality of water resources in a river-floodplain area affected by urban sources and recreational visitors

    NASA Astrophysics Data System (ADS)

    Derx, Julia; Schijven, Jack; Sommer, Regina; Kirschner, Alexander; Farnleitner, Andreas H.; Blaschke, Alfred Paul

    2016-04-01

    QMRAcatch, a tool to simulate microbial water quality including infection risk assessment, was previously developed and successfully tested at a Danube river site (Schijven et al. 2015). In the tool concentrations of target faecal microorganisms and viruses (TMVs) are computed at a point of interest (PI) along the main river and the floodplain river at daily intervals for a one year period. Even though faecal microbial pathogen concentrations in water resources are usually below the sample limit of detection, this does not ensure, that the water quality complies with a certain required health based target. The aim of this study was therefore to improve the predictability of relevant human pathogenic viruses, i.e. enterovirus and norovirus, in the studied river/floodplain area. This was done by following an innovative calibration strategy based on human-associated microbial source tracking (MST) marker data which were determined following the HF183 TaqMan assay (Green et al. 2011). The MST marker is strongly associated with human faeces and communal sewage, occurring there in numbers by several magnitudes higher than for human enteric pathogens (Mayer et al 2015). The calibrated tool was then evaluated with measured enterovirus concentrations at the PI and in the floodplain river. In the simulation tool the discharges of 5 wastewater treatment plants (WWTPs) were considered with point discharges along a 200 km reach of the Danube river. The MST marker and target virus concentrations at the PI at a certain day were computed based on the concentrations of the previous day, plus the wastewater concentrations times the WWTP discharge divided by the river discharge. A ratio of the river width was also considered, over which the MST marker and virus particles have fully mixed with river water. In the tool, the excrements from recreational visitors frequenting the floodplain area every day were assumed to be homogeneously distributed in the area. A binomial distributed

  10. Individual Difference Variables, Affective Differentiation, and the Structures of Affect

    PubMed Central

    Terracciano, Antonio; McCrae, Robert R.; Hagemann, Dirk; Costa, Paul T.

    2008-01-01

    Methodological arguments are usually invoked to explain variations in the structure of affect. Using self-rated affect from Italian samples (N = 600), we show that individual difference variables related to affective differentiation can moderate the observed structure. Indices of circumplexity (Browne, 1992) and congruence coefficients to the hypothesized target were used to quantify the observed structures. Results did not support the circumplex model as a universal structure. A circular structure with axes of activation and valence was approximated only among more affectively differentiated groups: students and respondents with high scores on Openness to Feelings and measures of negative emotionality. A different structure, with unipolar Positive Affect and Negative Affect factors, was observed among adults and respondents with low Openness to Feelings and negative emotionality. The observed structure of affect will depend in part on the nature of the sample studied. PMID:12932207

  11. Measuring spatial patterns in floodplains: A step towards understanding the complexity of floodplain ecosystems: Chapter 6

    USGS Publications Warehouse

    Murray Scown,; Martin Thoms,; DeJager, Nathan R.; Gilvear, David J.; Greenwood, Malcolm T.; Thoms, Martin C.; Wood, Paul J.

    2016-01-01

    Floodplains can be viewed as complex adaptive systems (Levin, 1998) because they are comprised of many different biophysical components, such as morphological features, soil groups and vegetation communities as well as being sites of key biogeochemical processing (Stanford et al., 2005). Interactions and feedbacks among the biophysical components often result in additional phenomena occuring over a range of scales, often in the absence of any controlling factors (sensu Hallet, 1990). This emergence of new biophysical features and rates of processing can lead to alternative stable states which feed back into floodplain adaptive cycles (cf. Hughes, 1997; Stanford et al., 2005). Interactions between different biophysical components, feedbacks, self emergence and scale are all key properties of complex adaptive systems (Levin, 1998; Phillips, 2003; Murray et al., 2014) and therefore will influence the manner in which we study and view spatial patterns. Measuring the spatial patterns of floodplain biophysical components is a prerequisite to examining and understanding these ecosystems as complex adaptive systems. Elucidating relationships between pattern and process, which are intrinsically linked within floodplains (Ward et al., 2002), is dependent upon an understanding of spatial pattern. This knowledge can help river scientists determine the major drivers, controllers and responses of floodplain structure and function, as well as the consequences of altering those drivers and controllers (Hughes and Cass, 1997; Whited et al., 2007). Interactions and feedbacks between physical, chemical and biological components of floodplain ecosystems create and maintain a structurally diverse and dynamic template (Stanford et al., 2005). This template influences subsequent interactions between components that consequently affect system trajectories within floodplains (sensu Bak et al., 1988). Constructing and evaluating models used to predict floodplain ecosystem responses to

  12. Field Flumes to Floodplains: Revealing the Influence of Flow Dynamics in Structuring Aquatic Ecosystems

    NASA Astrophysics Data System (ADS)

    Harvey, J. W.

    2011-12-01

    Decades of research has demonstrated the role of flood pulses in energy flow and nutrient cycling in large rivers. However, the study of hydroecology in small to medium size channels has often focused on static processes occurring during steady channel baseflow. Yet storm dynamics and their ecological effects are key issues for land managers responding to accelerating land use change in urban and agricultural areas, grazing lands, and in forested watersheds. As a means to understand the role of variable flows, researchers are increasingly moving towards study designs that explicitly address natural or experimentally altered flows in streams, or manipulation of flow in controlled "stair step" of experimental discharges in smaller field flumes. Studies often focus on both dissolved and fine particulate materials, their redistribution by stormflow, and physical effects of bedform migration and expansion and contraction of surface-water storage and hyporheic zones. In this framework investigators are seeking not only to identify the factors causing "hot spots" of biogeochemical transformation in streams, but also the "hot moments" related to flow variation and its interactions with geomorphic, sediment, and solute dynamics. Examples illustrating these advancements come from studies of flash floods from urban areas and their effects of solute and sediment dynamics in a 2nd order stream, nitrogen cycling and floodplain dynamics in a 5th order river, and longer term co-evolution of pulsed flow hydraulics, geomorphic form, and sediment and nutrient retention in two contrasting river and wetland corridors in the southwestern U.S. and southern Florida.

  13. Quantitative regularities in floodplain formation

    NASA Astrophysics Data System (ADS)

    Nevidimova, O.

    2009-04-01

    . Thus, the floodplain dynamics is determined by the amount of material Q(t), left as sediment (amount of warp on a unit of area) during the period of flooding, and the amount of material q(t), removed during the time between floods. With the floodplain height approaching some limit height Yl, which equals the maximal height of floods, Q(t)  0, а q(t)  max. From here, we can build a functional diagram of the floodplain height change depending on time: dY/dt=Q (t) - q (t) (1) This equation allows us to describe non-monotonous behavior of different floodplain massifs. As floodplain systems, like all geomorphosystems, are dissipative structures, they should eventually come to a stable condition: dY/dt=0. This mode is possible in cases: Q=q=0 and Q=q=const. In the first case, the floodplain level would reach the maximum height of flooding and would not be flooded any more. It would cause significant decrease in the amount of material left on its surface as sediments and the system would start to degrade. This variant is purely theoretical, as such conditions, where the streams of matter are absent, can appear only in a homogeneous environment. The second case characterizes the final stage in the formation of floodplain system as an integral unity in concrete external conditions and determines its dynamic equilibrium. In terms of the theory of dynamic systems, this condition corresponds to the limit cycle. Real floodplain systems never achieve it, but approach to it indefinitely closely, repeating themselves and not changing essentially in their basic morphological parameters. Thus, a high floodplain, approaching its limit height, shows morphological completeness. If for any reasons the floodplain surface becomes higher than the limit height Yl, it will not be flooded any more and will become a terrace, which means that the limit cycle of the floodplain system will be destroyed, as well as the system itself. The equation (1) allows to take into account the river

  14. How do long-term development and periodical changes of river-floodplain systems affect the fate of contaminants? Results from European rivers.

    PubMed

    Lair, G J; Zehetner, F; Fiebig, M; Gerzabek, M H; van Gestel, C A M; Hein, T; Hohensinner, S; Hsu, P; Jones, K C; Jordan, G; Koelmans, A A; Poot, A; Slijkerman, D M E; Totsche, K U; Bondar-Kunze, E; Barth, J A C

    2009-12-01

    In many densely populated areas, riverine floodplains have been strongly impacted and degraded by river channelization and flood protection dikes. Floodplains act as buffers for flood water and as filters for nutrients and pollutants carried with river water and sediment from upstream source areas. Based on results of the EU-funded "AquaTerra" project (2004-2009), we analyze changes in the dynamics of European river-floodplain systems over different temporal scales and assess their effects on contaminant behaviour and ecosystem functioning. We find that human-induced changes in the hydrologic regime of rivers have direct and severe consequences on nutrient cycling and contaminant retention in adjacent floodplains. We point out the complex interactions of contaminants with nutrient availability and other physico-chemical characteristics (pH, organic matter) in determining ecotoxicity and habitat quality, and draw conclusions for improved floodplain management.

  15. How do long-term development and periodical changes of river-floodplain systems affect the fate of contaminants? Results from European rivers.

    PubMed

    Lair, G J; Zehetner, F; Fiebig, M; Gerzabek, M H; van Gestel, C A M; Hein, T; Hohensinner, S; Hsu, P; Jones, K C; Jordan, G; Koelmans, A A; Poot, A; Slijkerman, D M E; Totsche, K U; Bondar-Kunze, E; Barth, J A C

    2009-12-01

    In many densely populated areas, riverine floodplains have been strongly impacted and degraded by river channelization and flood protection dikes. Floodplains act as buffers for flood water and as filters for nutrients and pollutants carried with river water and sediment from upstream source areas. Based on results of the EU-funded "AquaTerra" project (2004-2009), we analyze changes in the dynamics of European river-floodplain systems over different temporal scales and assess their effects on contaminant behaviour and ecosystem functioning. We find that human-induced changes in the hydrologic regime of rivers have direct and severe consequences on nutrient cycling and contaminant retention in adjacent floodplains. We point out the complex interactions of contaminants with nutrient availability and other physico-chemical characteristics (pH, organic matter) in determining ecotoxicity and habitat quality, and draw conclusions for improved floodplain management. PMID:19604610

  16. Characterization of redox-related soil microbial communities along a river floodplain continuum by fatty acid methyl ester (FAME) and 16S rRNA genes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Redox states affect substrate availability and energy transformation, and, thus, play a crucial role in regulating soil microbial abundance, diversity, and community structure. We evaluated microbial communities in soils under oxic, intermittent, and anoxic conditions along a river floodplain conti...

  17. Vegetation, soil, and flooding relationships in a blackwater floodplain forest

    USGS Publications Warehouse

    Burke, M.K.; King, S.L.; Gartner, D.; Eisenbies, M.H.

    2003-01-01

    Hydroperiod is considered the primary determinant of plant species distribution in temperate floodplain forests, but most studies have focused on alluvial (sediment-laden) river systems. Few studies have evaluated plant community relationships in blackwater river systems of the South Atlantic Coastal Plain of North America. In this study, we characterized the soils, hydroperiod, and vegetation communities and evaluated relationships between the physical and chemical environment and plant community structure on the floodplain of the Coosawhatchie River, a blackwater river in South Carolina, USA. The soils were similar to previous descriptions of blackwater floodplain soils but had greater soil N and P availability, substantially greater clay content, and lower soil silt content than was previously reported for other blackwater river floodplains. Results of a cluster analysis showed there were five forest communities on the site, and both short-term (4 years) and long-term (50 years) flooding records documented a flooding gradient: water tupelo community > swamp tupelo > laurel oak = overcup oak > mixed oak. The long-term hydrologic record showed that the floodplain has flooded less frequently from 1994 to present than in previous decades. Detrended correspondence analysis of environmental and relative basal area values showed that 27% of the variation in overstory community structure could be explained by the first two axes; however, fitting the species distributions to the DCA axes using Gaussian regression explained 67% of the variation. Axes were correlated with elevation (flooding intensity) and soil characteristics related to rooting volume and cation nutrient availability. Our study suggests that flooding is the major factor affecting community structure, but soil characteristics also may be factors in community structure in blackwater systems. ?? 2003, The Society of Wetland Scientists.

  18. Genetic structure among and within peripheral and central populations of three endangered floodplain violets.

    PubMed

    Eckstein, R L; O'neill, R A; Danihelka, J; Otte, A; Köhler, W

    2006-08-01

    Understanding the partitioning of genetic variance in peripheral and central populations may shed more light on the effects of genetic drift and gene flow on population genetic structure and, thereby, improve attempts to conserve genetic diversity. We analysed genetic structure of peripheral and central populations of three insect-pollinated violets (Viola elatior, Viola pumila, Viola stagnina) to evaluate to what extent these patterns can be explained by gene flow and genetic drift. Amplified fragment length polymorphism was used to analyse 930 individuals of 50 populations. Consistent with theoretical predictions, peripheral populations were smaller and more isolated, differentiation was stronger, and genetic diversity and gene flow lower in peripheral populations of V. pumila and V. stagnina. In V. elatior, probably historic fragmentation effects linked to its specific habitat type were superimposed on the plant geographic (peripheral-central) patterns, resulting in lower relative importance of gene flow in central populations. Genetic variation between regions (3-6%), among (30-37%) and within populations (60-64%) was significant. Peripheral populations lacked markers that were rare and localized in central populations. Loss of widespread markers in peripheral V. stagnina populations indicated genetic erosion. Autocorrelation within populations was statistically significant up to a distance of 10-20 m. Higher average genetic similarity in peripheral populations than in central ones indicated higher local gene flow, probably owing to management practices. Peripheral populations contributed significantly to genetic variation and contained unique markers, which made them valuable for the conservation of genetic diversity.

  19. Quantitative regularities in floodplain formation

    NASA Astrophysics Data System (ADS)

    Nevidimova, O.

    2009-04-01

    . Thus, the floodplain dynamics is determined by the amount of material Q(t), left as sediment (amount of warp on a unit of area) during the period of flooding, and the amount of material q(t), removed during the time between floods. With the floodplain height approaching some limit height Yl, which equals the maximal height of floods, Q(t)  0, а q(t)  max. From here, we can build a functional diagram of the floodplain height change depending on time: dY/dt=Q (t) - q (t) (1) This equation allows us to describe non-monotonous behavior of different floodplain massifs. As floodplain systems, like all geomorphosystems, are dissipative structures, they should eventually come to a stable condition: dY/dt=0. This mode is possible in cases: Q=q=0 and Q=q=const. In the first case, the floodplain level would reach the maximum height of flooding and would not be flooded any more. It would cause significant decrease in the amount of material left on its surface as sediments and the system would start to degrade. This variant is purely theoretical, as such conditions, where the streams of matter are absent, can appear only in a homogeneous environment. The second case characterizes the final stage in the formation of floodplain system as an integral unity in concrete external conditions and determines its dynamic equilibrium. In terms of the theory of dynamic systems, this condition corresponds to the limit cycle. Real floodplain systems never achieve it, but approach to it indefinitely closely, repeating themselves and not changing essentially in their basic morphological parameters. Thus, a high floodplain, approaching its limit height, shows morphological completeness. If for any reasons the floodplain surface becomes higher than the limit height Yl, it will not be flooded any more and will become a terrace, which means that the limit cycle of the floodplain system will be destroyed, as well as the system itself. The equation (1) allows to take into account the river

  20. Fusion of UAV photogrammetry and digital optical granulometry for detection of structural changes in floodplains

    NASA Astrophysics Data System (ADS)

    Langhammer, Jakub; Lendzioch, Theodora; Mirijovsky, Jakub

    2016-04-01

    Granulometric analysis represents a traditional, important and for the description of sedimentary material substantial method with various applications in sedimentology, hydrology and geomorphology. However, the conventional granulometric field survey methods are time consuming, laborious, costly and are invasive to the surface being sampled, which can be limiting factor for their applicability in protected areas.. The optical granulometry has recently emerged as an image analysis technique, enabling non-invasive survey, employing semi-automated identification of clasts from calibrated digital imagery, taken on site by conventional high resolution digital camera and calibrated frame. The image processing allows detection and measurement of mixed size natural grains, their sorting and quantitative analysis using standard granulometric approaches. Despite known limitations, the technique today presents reliable tool, significantly easing and speeding the field survey in fluvial geomorphology. However, the nature of such survey has still limitations in spatial coverage of the sites and applicability in research at multitemporal scale. In our study, we are presenting novel approach, based on fusion of two image analysis techniques - optical granulometry and UAV-based photogrammetry, allowing to bridge the gap between the needs of high resolution structural information for granulometric analysis and spatially accurate and data coverage. We have developed and tested a workflow that, using UAV imaging platform enabling to deliver seamless, high resolution and spatially accurate imagery of the study site from which can be derived the granulometric properties of the sedimentary material. We have set up a workflow modeling chain, providing (i) the optimum flight parameters for UAV imagery to balance the two key divergent requirements - imagery resolution and seamless spatial coverage, (ii) the workflow for the processing of UAV acquired imagery by means of the optical

  1. Metal accumulation in earthworms inhabiting floodplain soils.

    PubMed

    Vijver, Martina G; Vink, Jos P M; Miermans, Cornelis J H; van Gestel, Cornelis A M

    2007-07-01

    The main factors contributing to variation in metal concentrations in earthworms inhabiting floodplain soils were investigated in three floodplains differing in inundation frequency and vegetation type. Metal concentrations in epigeic earthworms showed larger seasonal variations than endogeic earthworms. Variation in internal levels between sampling intervals were largest in earthworms from floodplain sites frequently inundated. High and low frequency flooding did not result in consistent changes in internal metal concentrations. Vegetation types of the floodplains did not affect metal levels in Lumbricus rubellus, except for internal Cd levels, which were positively related to the presence of organic litter. Internal levels of most essential metals were higher in spring. In general, no clear patterns in metal uptake were found and repetition of the sampling campaign will probably yield different results. PMID:17254683

  2. Hydrological Signature From River-Floodplain Interactions

    NASA Astrophysics Data System (ADS)

    Paiva, R. C. D.; Fleischmann, A. S.; Collischonn, W.; Sorribas, M.; Pontes, P. R.

    2015-12-01

    Understanding river-floodplain hydraulic processes is fundamental to promote comprehension of related water paths, biogeochemicalcyclesand ecosystems. Large river basins around the globe present enormous developed floodplains, which strongly affect flood waves and water dynamics. Since most of these river-floodplain interactions are not monitored, it is interesting to develop strategies to understand such processes through characteristic hydrological signatures, e.g. hydrographs. We studied observed hydrographs from large South American rivers and found that in several cases rivers with extensive wetlands present a particular hydrograph shape, with slower rising limb in relation to the receding one, due to storage effects and the associated decrease of wave celerity with stage. A negative asymmetry in the hydrograph is generated, which is higher when more water flows through floodplains upstream of the observed point. Finally, we studied the Amazon basin using gauged information and simulation results from the MGB-IPH regional hydrological model. Major rivers with larger wetland areas (e.g. Purus, Madeira and Juruá) were identified with higher negative asymmetry in their hydrographs. The hydrodynamic model was run in scenarios with and without floodplains, and results supported that floodplain storage affects hydrographs in creating a negative asymmetry, besides attenuating peaks, increasing hydrograph smoothness and increasing minimum flows. Finally, different wetland types could be distinguished with hydrograph shape, e.g. differing wetlands fed by local rainfall from wetlands due to overbank flow (floodplains). These metrics and concepts on hydrograph features have great potential to infer about river-floodplain processes from large rivers and wetland systems.

  3. STRUCTURAL AND AFFECTIVE ASPECTS OF CLASSROOM CLIMATE.

    ERIC Educational Resources Information Center

    WALBERG, HERBERT J.

    USING THE CLASSROOM AS THE UNIT OF ANALYSIS A 25 PERCENT RANDOM SAMPLE OF STUDENTS IN 72 CLASSES FROM ALL PARTS OF THE COUNTRY TOOK THE CLASSROOM CLIMATE QUESTIONNAIRE IN ORDER TO INVESTIGATE THE RELATIONSHIP BETWEEN STRUCTURAL (ORGANIZATIONAL) AND AFFECTIVE (PERSONAL INTERACTION BETWEEN GROUP MEMBERS) DIMENSIONS OF GROUP CLIMATE. REGRESSION AND…

  4. How membrane surface affects protein structure.

    PubMed

    Bychkova, V E; Basova, L V; Balobanov, V A

    2014-12-01

    The immediate environment of the negatively charged membrane surface is characterized by decreased dielectric constant and pH value. These conditions can be modeled by water-alcohol mixtures at moderately low pH. Several globular proteins were investigated under these conditions, and their conformational behavior in the presence of phospholipid membranes was determined, as well as under conditions modeling the immediate environment of the membrane surface. These proteins underwent conformational transitions from the native to a molten globule-like state. Increased flexibility of the protein structure facilitated protein functioning. Our experimental data allow understanding forces that affect the structure of a protein functioning near the membrane surface (in other words, in the membrane field). Similar conformational states are widely reported in the literature. This indicates that the negatively charged membrane surface can serve as a moderately denaturing agent in the cell. We conclude that the effect of the membrane field on the protein structure must be taken into account.

  5. Soil characteristics of a hyperseasonal cerrado compared to a seasonal cerrado and a floodplain grassland: implications for plant community structure.

    PubMed

    Amorim, P K; Batalha, M A

    2006-05-01

    Savannas may be divided according to their seasonality into semi-seasonal, seasonal, hyperseasonal, or marshy savannas. Hyperseasonal savannas are characterized by the alternation of two contrasting stresses during each annual cycle, one induced by drought and fire and the other, by waterlogging. In South America, the largest savanna region is the Brazilian cerrado, in which there are few hyperseasonal areas that become waterlogged in the rainy season. The cerrado soils are generally well drained, but in central Brazil there is a small cerrado area in which the soil is poorly drained and which becomes waterlogged in the middle of the rainy season, allowing the appearance of a hyperseasonal cerrado. As long as soil is important in the ecology of the cerrado vegetation, we asked whether the waterlogging in this hyperseasonal cerrado implied that there were differences in soil characteristics in relation to a seasonal cerrado, which is not waterlogged in the rainy season, and to a floodplain grassland, which remains waterlogged throughout the year. In each environment, we randomly selected ten points, in which we collected soil samples in the mid-rainy season for chemical and granulometric analyses. For all variables, we found significant differences among the three environments, at least at one of the depths. Nevertheless, when we took into account all the variables together, we observed that the soils under the hyperseasonal and seasonal cerrados were similar and both were different to the soil under the floodplain grassland. The soil under the floodplain grassland was related to larger amounts of clay, silt, organic matter, phosphorus, aluminium, aluminium saturation, cation exchange capacity, and sum of bases, whereas soils under hyperseasonal and seasonal cerrados were related to higher pH values, base saturation, calcium, magnesium, and sand. As long as the soil under both cerrados was chemically and physically similar, the duration of waterlogging in the

  6. Soil characteristics of a hyperseasonal cerrado compared to a seasonal cerrado and a floodplain grassland: implications for plant community structure.

    PubMed

    Amorim, P K; Batalha, M A

    2006-05-01

    Savannas may be divided according to their seasonality into semi-seasonal, seasonal, hyperseasonal, or marshy savannas. Hyperseasonal savannas are characterized by the alternation of two contrasting stresses during each annual cycle, one induced by drought and fire and the other, by waterlogging. In South America, the largest savanna region is the Brazilian cerrado, in which there are few hyperseasonal areas that become waterlogged in the rainy season. The cerrado soils are generally well drained, but in central Brazil there is a small cerrado area in which the soil is poorly drained and which becomes waterlogged in the middle of the rainy season, allowing the appearance of a hyperseasonal cerrado. As long as soil is important in the ecology of the cerrado vegetation, we asked whether the waterlogging in this hyperseasonal cerrado implied that there were differences in soil characteristics in relation to a seasonal cerrado, which is not waterlogged in the rainy season, and to a floodplain grassland, which remains waterlogged throughout the year. In each environment, we randomly selected ten points, in which we collected soil samples in the mid-rainy season for chemical and granulometric analyses. For all variables, we found significant differences among the three environments, at least at one of the depths. Nevertheless, when we took into account all the variables together, we observed that the soils under the hyperseasonal and seasonal cerrados were similar and both were different to the soil under the floodplain grassland. The soil under the floodplain grassland was related to larger amounts of clay, silt, organic matter, phosphorus, aluminium, aluminium saturation, cation exchange capacity, and sum of bases, whereas soils under hyperseasonal and seasonal cerrados were related to higher pH values, base saturation, calcium, magnesium, and sand. As long as the soil under both cerrados was chemically and physically similar, the duration of waterlogging in the

  7. Risk-based zoning for urbanizing floodplains.

    PubMed

    Porse, Erik

    2014-01-01

    Urban floodplain development brings economic benefits and enhanced flood risks. Rapidly growing cities must often balance the economic benefits and increased risks of floodplain settlement. Planning can provide multiple flood mitigation and environmental benefits by combining traditional structural measures such as levees, increasingly popular landscape and design features (green infrastructure), and non-structural measures such as zoning. Flexibility in both structural and non-structural options, including zoning procedures, can reduce flood risks. This paper presents a linear programming formulation to assess cost-effective urban floodplain development decisions that consider benefits and costs of development along with expected flood damages. It uses a probabilistic approach to identify combinations of land-use allocations (residential and commercial development, flood channels, distributed runoff management) and zoning regulations (development zones in channel) to maximize benefits. The model is applied to a floodplain planning analysis for an urbanizing region in the Baja Sur peninsula of Mexico. The analysis demonstrates how (1) economic benefits drive floodplain development, (2) flexible zoning can improve economic returns, and (3) cities can use landscapes, enhanced by technology and design, to manage floods. The framework can incorporate additional green infrastructure benefits, and bridges typical disciplinary gaps for planning and engineering.

  8. Risk-based zoning for urbanizing floodplains.

    PubMed

    Porse, Erik

    2014-01-01

    Urban floodplain development brings economic benefits and enhanced flood risks. Rapidly growing cities must often balance the economic benefits and increased risks of floodplain settlement. Planning can provide multiple flood mitigation and environmental benefits by combining traditional structural measures such as levees, increasingly popular landscape and design features (green infrastructure), and non-structural measures such as zoning. Flexibility in both structural and non-structural options, including zoning procedures, can reduce flood risks. This paper presents a linear programming formulation to assess cost-effective urban floodplain development decisions that consider benefits and costs of development along with expected flood damages. It uses a probabilistic approach to identify combinations of land-use allocations (residential and commercial development, flood channels, distributed runoff management) and zoning regulations (development zones in channel) to maximize benefits. The model is applied to a floodplain planning analysis for an urbanizing region in the Baja Sur peninsula of Mexico. The analysis demonstrates how (1) economic benefits drive floodplain development, (2) flexible zoning can improve economic returns, and (3) cities can use landscapes, enhanced by technology and design, to manage floods. The framework can incorporate additional green infrastructure benefits, and bridges typical disciplinary gaps for planning and engineering. PMID:25500464

  9. Association between wetland disturbance and biological attributes in floodplain wetlands

    USGS Publications Warehouse

    Chipps, S.R.; Hubbard, D.E.; Werlin, K.B.; Haugerud, N.J.; Powell, K.A.; Thompson, John; Johnson, T.

    2006-01-01

    We quantified the influence of agricultural activities on environmental and biological conditions of floodplain wetlands in the upper Missouri River basin. Seasonally-flooded wetlands were characterized as low impact (non-disturbed) or high impact (disturbed) based on local land use. Biological data collected from these wetlands were used to develop a wetland condition index (WCI). Fourteen additional wetlands were sampled to evaluate the general condition of seasonally-flooded floodplain wetlands. Structural and functional attributes of macrophyte, algae, and macroinvertebrate communities were tested as candidate metrics for assessing biotic responses. The WCI we developed used six biological metrics to discriminate between disturbed and non-disturbed wetlands: 1) biomass of Culicidae larvae, 2) abundance of Chironomidae larvae, 3) macroinvertebrate diversity, 4) total number of plant species, 5) the proportion of exotic plant species, and 6) total number of sensitive diatom species. Disturbed wetlands had less taxa richness and species diversity and more exotic and nuisance (e.g., mosquitoes) species. Environmental differences between low and high impact wetlands included measures of total potassium, total phosphorus, total nitrogen, alkalinity, conductance, and sediment phosphorus concentration. Canonical analyses showed that WCI scores were weakly correlated (P = 0.057) with environmental variables in randomly selected wetlands. In addition, mean WCI score for random wetlands was higher than that for high impact wetlands, implying that floodplain wetlands were less impacted by the types of agricultural activities affecting high impact sites. Inter-year sampling of some wetlands revealed that WCI metrics were correlated in 2000 and 2001, implying that biological metrics provided useful indicators of disturbance in floodplain wetlands. ?? 2006, The Society of Wetland Scientists.

  10. Developing Hierarchical Structures Integrating Cognition and Affect.

    ERIC Educational Resources Information Center

    Hurst, Barbara Martin

    Several categories of the affective domain are important to the schooling process. Schools are delegated the responsibility of helping students to clarify their esthetic, instrumental, and moral values. Three areas of affect are related to student achievement: subject-related affect, school-related affect, and academic self concept. In addition,…

  11. Planning practice in support of economically and environmentally sustainable roads in floodplains: the case of the Mekong delta floodplains.

    PubMed

    Douven, Wim; Buurman, Joost

    2013-10-15

    Road development in relatively undisturbed floodplain systems, such as the floodplains of the Mekong River, will impact hydraulics and interrupt the natural flow of water. This affects the ecology and environment, and the livelihoods of people who depend on fishing and agriculture. On the other hand, floods can severely damage road infrastructure in years with large floods and can cause high annual maintenance costs. Improving road development practices in floodplains is a complex, multidimensional task involving hydraulic and geotechnical analysis, ecosystem analysis, socio-economic analysis, policy analysis, etc. This paper analyses the planning practice of road development and rehabilitation and how this practice can be improved in support of economically and environmentally sustainable roads in floodplains. It is concluded that although ample technical, planning and environmental assessment guidelines exist, guidelines need updating to address cumulative impacts at floodplain level and factors hampering the implementation in guidelines should be addressed in the guideline design (process).

  12. Planning practice in support of economically and environmentally sustainable roads in floodplains: the case of the Mekong delta floodplains.

    PubMed

    Douven, Wim; Buurman, Joost

    2013-10-15

    Road development in relatively undisturbed floodplain systems, such as the floodplains of the Mekong River, will impact hydraulics and interrupt the natural flow of water. This affects the ecology and environment, and the livelihoods of people who depend on fishing and agriculture. On the other hand, floods can severely damage road infrastructure in years with large floods and can cause high annual maintenance costs. Improving road development practices in floodplains is a complex, multidimensional task involving hydraulic and geotechnical analysis, ecosystem analysis, socio-economic analysis, policy analysis, etc. This paper analyses the planning practice of road development and rehabilitation and how this practice can be improved in support of economically and environmentally sustainable roads in floodplains. It is concluded that although ample technical, planning and environmental assessment guidelines exist, guidelines need updating to address cumulative impacts at floodplain level and factors hampering the implementation in guidelines should be addressed in the guideline design (process). PMID:23735460

  13. Diel variations in the assemblage structure and foraging ecology of larval and 0+ year juvenile fishes in a man-made floodplain waterbody.

    PubMed

    Tewson, L H; Cowx, I G; Nunn, A D

    2016-04-01

    This study investigated diel variations in zooplankton composition and abundance, and the species composition, density, size structure, feeding activity, diet composition and prey selection of larval and 0+ year juvenile fishes in the littoral of a man-made floodplain waterbody over five 24 h periods within a 57 day period. There was a significant difference in the species composition of diurnal and nocturnal catches, with most species consistently peaking in abundance either during daylight or at night, reflecting their main activity period. There were no consistent diel patterns in assemblage structure or the abundance of some species, however, most likely, respectively, due to the phenology of fish hatching and ontogenetic shifts in diel behaviour or habitat use. There were few clear diel patterns in the diet composition or prey selection of larval and 0+ year juvenile roach Rutilus rutilus and perch Perca fluviatilis, with most taxa consistently selected or avoided irrespective of the time of day or night, and no obvious shift between planktonic and benthic food sources, but dietary overlap suggested that interspecific interactions were probably strongest at night. It is essential that sampling programmes account for the diel ecology of the target species, as diurnal surveys alone could produce inaccurate assessments of resource use. The relative lack of consistent diel patterns in this study suggests that multiple 24 h surveys are required in late spring and early summer to provide accurate assessments of 0+ year fish assemblage structure and foraging ecology. PMID:26935792

  14. Synergies between Danube Floodplain revitalization, flood risk mapping and spatial planning

    NASA Astrophysics Data System (ADS)

    Nichersu, Iulian; Marin, Eugenia; Mierla, Marian; Sela, Florentina; Nichersu, Iuliana; Trifanov, Cristian

    2014-05-01

    The Danube River must be considered more than a subject of hydraulics. Together with its major riverbed and flooded meadow, represents a very complex ecosystem that provides habitat for a very rich flora and fauna, and also a support for the socio-economical activities. During time, the ecological balance of Danube River has suffered alteration processes because of continuously development of human society. In the alteration process of the Danube have been destroyed dominating natural systems and created instead industrial structures with economical purpose such as navigation, hydro-energy, agriculture, harbors that are damaging the Danube River by losing the floodplains and natural morphological structures, determining the Danube Floodplain to struggle with increasing flood risks and actual floods in the last few years. Because the Danube was recently channelized and enclosed by dikes, there is hardly room for the reduction of peak flow during rainy periods or for the development of nature along the river. Due to climate change and large-scale deforestation, these peak flows occur not only more frequently, but they also carry a greater volume of water over a shorter time, as seen during the summers of 2004 and 2005 and spring 2006, 2010 when a large part of the region flooded and required large-scale evacuations. The catastrophic flood events in the Danube Basin in particular reveal the vulnerability of our society against extreme natural events. With the increase of population and industrialization, the settling areas and land use activities spread in floodplain areas seeming protected or hardly affected. Hence, the Romanian Danube Floodplain has been the subject of three major research projects: "Ecological and economical restoration of Lower Danube Floodplain - Romanian Sector", "Danube River revitalization" within SEE project 'Danube River Network of Protected Areas" and "Beneficiaries and flood risk assessment in Danube Floodplain". The synergic objective of

  15. Sedimentation patterns across a Coastal Plain floodplain: The importance of hydrogeomorphic influences and cross-floodplain connectivity

    NASA Astrophysics Data System (ADS)

    Kaase, Christopher T.; Kupfer, John A.

    2016-09-01

    The floodplains of large Coastal Plain rivers in the southeastern U.S. are important long-term storage sites for alluvial sediment and nutrients. Yet considerable uncertainty surrounds sediment dynamics on many large river floodplains and, in particular, the local scale factors that affect the flux of sediment and nutrients from rivers onto their floodplains and their subsequent deposition. This research quantifies short-term rates of sediment deposition from 2012 to 2014 on floodplain sites at Congaree National Park using feldspar pads. Sediment deposition rates ranged from 0.1 to 15.6 cm (median = 1.46 cm) and were closely associated with inundation frequency and geomorphic position. Cross-floodplain distributary channels served as particularly important conduits for moving sediment onto the floodplain. Physical and chemical analyses of soil samples demonstrated that the most flood-exposed sites had higher major nutrient and micronutrient levels (especially of phosphorus) and more diverse nutrient compositions. This research advances current understandings of lateral floodplain connectivity by demonstrating the complex effects of regional hydrology and local floodplain environmental characteristics on the supply of sediment and nutrients.

  16. Effects of Floodplain Vegetation on Momentum Transfer in Compound Channel

    NASA Astrophysics Data System (ADS)

    Hasegawa, Fumiaki; Yamamoto, Takuya; Jahra, Fatima; Kawahara, Yoshihisa

    Better management of riparian vegetation for flood control and environmental preservation requires in-depth understanding of flow characteristics in the presence of vegetation. This study aims at clarifying the flow structure and lateral momentum transfer process in vegetated compound channels through experiments and numerical simulations. Two types of vegetation zone on a floodplain are discussed. In the first case a floodplain is fully covered by vegetation. In the other case a floodplain has a belt of vegetation zone along the interface between main channel and floodplain. The measured data are compared with the numerical results that are obtained using a non-linear k-ɛ model and a vegetation model. It is found that the numerical model can reproduce the main characteristics of the flow and that the convection and the turbulent diffusion play important roles in the lateral momentum transfer across the interface between vegetated floodplain and main channel.

  17. Morphodynamics of Floodplain Chute Channels

    NASA Astrophysics Data System (ADS)

    David, S. R.; Edmonds, D. A.

    2015-12-01

    Floodplain chute channel formation is a key process that can enable rivers to transition from single-thread to multi-thread planform geometries. Floodplain chute channels are usually incisional channels connecting topographic lows across point bars and in the floodplain. Surprisingly, it is still not clear what conditions promote chute channel formation and what governs their morphodynamic behavior. Towards this end we have initiated an empirical and theoretical study of floodplain chute channels in Indiana, USA. Using elevation models and satellite imagery we mapped 3064 km2 of floodplain in Indiana, and find that 37.3% of mapped floodplains in Indiana have extensive chute channel networks. These chute channel networks consist of two types of channel segments: meander cutoffs of the main channel and chute channels linking the cutoffs together. To understand how these chute channels link meander cutoffs together and eventually create floodplain channel networks we use Delft3D to explore floodplain morphodynamics. Our first modeling experiment starts from a generic floodplain prepopulated with meander cutoffs to test under what conditions chute channels form.We find that chute channel formation is optimized at an intermediate flood discharge. If the flood discharge is too large the meander cutoffs erosively diffuse, whereas if the floodwave is too small the cutoffs fill with sediment. A moderately sized floodwave reworks the sediment surrounding the topographic lows, enhancing the development of floodplain chute channels. Our second modeling experiments explore how floodplain chute channels evolve on the West Fork of the White River, Indiana, USA. We find that the floodplain chute channels are capable of conveying the entire 10 yr floodwave (Q=1330m3/s) leaving the inter-channel areas dry. Moreover, the chute channels can incise into the floodplain while the margins of channels are aggrading, creating levees. Our results suggest that under the right conditions

  18. Geologic structures that affect Appalachian coal mines

    SciTech Connect

    Chase, F.E. )

    1993-01-01

    Hazardous geologic structures found in Appalachian coal mines have been responsible for numerous injuries and fatalities. In addition, these structures have been responsible for downtime and in some instances have even resulted in mine closures. For these reasons, the US Bureau of Mines has investigate the physical characteristics, occurrences, and support strategies to help anticipate and better control these structures. Structures that are addressed in this paper include slips, slickensides, clay veins, kettlebottoms, and sandstone channels.

  19. The influence of floodplains on mercury availability

    SciTech Connect

    Wallschlaeger, D.; Wilken, R.D.

    1997-09-01

    The floodplains of the German river Elbe affect the mercury distribution in the river system in two different ways: they act both as a medium-term sink and as a long-term source. The large amounts of mercury deposited onto the floodplains during annual floodings are first effectively fixed in the soils, rendering them basically unavailable. Sequential extraction experiments reveal that only a small fraction of the mercury (< 3%) is present in available forms, whereas the vast majority is associated with humic substances or present in sulfidic binding forms. After deposition, a small fraction of the total mercury is gradually remobilized into the aqueous phase bound passively to water-soluble humic acids. The availability of mercury in these complexes is still low, since environmental influences such as changes in pH or redox potential and competition with other cations do not cause any mercury liberation. In the next step, reactions in the aqueous phase lead to the formation of the highly available volatile species Hg{sup 0} and dimethylmercury (DMM). Their evaporation gives rise to a strong mercury flux from the floodplains into the atmosphere. Preliminary mass balances indicate that the majority of the deposited mercury stays bound in the floodplain soils, while small amounts are emitted back into the river`s ecosystem. Atmospheric emission is more important as a remobilization pathway than aquatic export.

  20. Floodplain forest loss and changes in forest community composition and structure in the upper Mississippi River: a wildlife habitat at risk

    USGS Publications Warehouse

    Knutson, M.G.; Klaas, E.E.

    1998-01-01

    Large floodplain forests represent a threatened and endangered type of ecosystem in the United States. Estimates of cumulative losses of floodplain forest range from 57% to 95% at different locations within the continental United Stales. Floodplain forests of the Upper Mississippi River (UMR) have significantly declined in extent due to agriculture, lock and dam construction, and urban development since European settlement. We collected data on shrubs, herbs, and trees from 56 floodplain forest plots in 1992 and compared our results with a previous analysis of historical tree data from the same area recorded by the General Land Office Survey in the 1840s. Acer saccharinum strongly dominates among mature trees and its relative dominance has increased over time. Salix spp. And Betula nigra have declined in relative dominance. Tree sizes are similar to those of presettlement forests, but present forests have fewer trees. The lack of early successional tree species and a trend toward an increasing monoculture of A. Saccharinum in the mature stages indicate problems with regeneration. Because floodplain forests represent a rare habitat type, losses and changes in habitat quality could pose serious problems for wildlife that depend upon these habitats, especially birds.

  1. Floodplain ecosystem processes

    NASA Astrophysics Data System (ADS)

    Melack, John M.; Novo, Evlyn M. L. M.; Forsberg, Bruce R.; Piedade, Maria T. F.; Maurice, Laurence

    Floodplains represent a major component of the central Amazon Basin and influence the hydrology, ecology, and biogeochemistry. Hess et al. (2003) used a classification of synthetic aperture radar data with 100 m resolution for a 1.77 million km2 quadrat in central Amazonia and identified 17% as wetland most of which was inundated a portion of each year. Total net production attributed to flooded forests (excluding wood increments), aquatic macrophytes, phytoplankton, and periphyton for the 1.77 million km2 quadrat was estimated to be about 300 Tg C a-1. Flooded forests accounted for 62% of the total, aquatic macrophytes accounted for 34%, and the remaining 4% was associated with periphyton and phytoplankton. Approximately 10% of the total is the amount of organic carbon exported annually by the Amazon River according to Richey et al. (1990), methane emission is about 2.5% according to Melack et al. (2004), and a similar percent is estimated to be buried in sediments. The remaining portion is close to being sufficient to fuel the respiration that results in the degassing of 210 ± 60 Tg C a-1 as carbon dioxide from the rivers and floodplains according to Richey et al. (2002). Variations in the distribution and inundation of floodplain habitats play a key role in the ecology and production of many commercially important freshwater fish. A significant relationship exists between maximum inundated area lagged by 5 years and annual yield of omnivores.

  2. Floodplain Backwater Restoration: A Case Study

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Current thinking in stream ecology emphasizes the importance of floodplain backwaters within lowland riverine ecosystems. However, these types of habitat are becoming increasingly rare as development is transforming floodplain landscapes in fundamental ways. Two floodplain backwaters (severed mean...

  3. Ordination of breeding birds in relation to environmental gradients in three southeastern United States floodplain forests

    USGS Publications Warehouse

    Wakeley, J.S.; Guilfoyle, M.P.; Antrobus, T.J.; Fischer, R.A.; Barrow, W.C.; Hamel, P.B.

    2007-01-01

    We used an ordination approach to identify factors important to the organization of breeding bird communities in three floodplains: Cache River, Arkansas (AR), Iatt Creek, Louisiana (LA), and the Coosawhatchie River, South Carolina (SC), USA. We used 5-min point counts to sample birds in each study area each spring from 1995 to 1998, and measured ground-surface elevations and a suite of other habitat variables to investigate bird distributions and community characteristics in relation to important environmental gradients. In both AR and SC, the average number of Neotropical migrant species detected was lowest in semipermanently flooded Nyssa aquatica Linnaeus habitats and greatest in the highest elevation floodplain zone. Melanerpes carolinus Linnaeus, Protonotaria citrea Boddaert, Quiscalus quiscula Linnaeus, and other species were more abundant in N. aquatica habitats, whereas Wilsonia citrina Boddaert, Oporornis formosus Wilson, Vireo griseus Boddaert, and others were more abundant in drier floodplain zones. In LA, there were no significant differences in community metrics or bird species abundances among forest types. Canonical correspondence analyses revealed that structural development of understory vegetation was the most important factor affecting bird distributions in all three study areas; however, potential causes of these structural gradients differed. In AR and SC, differences in habitat structure were related to the hydrologic gradient, as indexed by ground-surface elevation. In LA, structural variations were related mainly to the frequency of canopy gaps. Thus, bird communities in all three areas appeared to be organized primarily in response to repeated localized disturbance. Our results suggest that regular disturbance due to flooding plays an important role in structuring breeding bird communities in floodplains subject to prolonged inundation, whereas other agents of disturbance (e.g., canopy gaps) may be more important in headwater systems

  4. Structural Factors Affecting Health Examination Behavioral Intention.

    PubMed

    Huang, Hui-Ting; Kuo, Yu-Ming; Wang, Shiang-Ru; Wang, Chia-Fen; Tsai, Chung-Hung

    2016-04-01

    Disease screening instruments used for secondary prevention can facilitate early determination and treatment of pathogenic factors, effectively reducing disease incidence, mortality rates, and health complications. Therefore, people should be encouraged to receive health examinations for discovering potential pathogenic factors before symptoms occur. Here, we used the health belief model as a foundation and integrated social psychological factors and investigated the factors influencing health examination behavioral intention among the public in Taiwan. In total, 388 effective questionnaires were analyzed through structural model analysis. Consequently, this study yielded four crucial findings: (1) The established extended health belief model could effectively predict health examination behavioral intention; (2) Self-efficacy was the factor that most strongly influenced health examination behavioral intention, followed by health knowledge; (3) Self-efficacy substantially influenced perceived benefits and perceived barriers; (4) Health knowledge and social support indirectly influenced health examination behavioral intention. The preceding results can effectively increase the acceptance and use of health examination services among the public, thereby facilitating early diagnosis and treatment and ultimately reducing disease and mortality rates. PMID:27043606

  5. Structural Factors Affecting Health Examination Behavioral Intention

    PubMed Central

    Huang, Hui-Ting; Kuo, Yu-Ming; Wang, Shiang-Ru; Wang, Chia-Fen; Tsai, Chung-Hung

    2016-01-01

    Disease screening instruments used for secondary prevention can facilitate early determination and treatment of pathogenic factors, effectively reducing disease incidence, mortality rates, and health complications. Therefore, people should be encouraged to receive health examinations for discovering potential pathogenic factors before symptoms occur. Here, we used the health belief model as a foundation and integrated social psychological factors and investigated the factors influencing health examination behavioral intention among the public in Taiwan. In total, 388 effective questionnaires were analyzed through structural model analysis. Consequently, this study yielded four crucial findings: (1) The established extended health belief model could effectively predict health examination behavioral intention; (2) Self-efficacy was the factor that most strongly influenced health examination behavioral intention, followed by health knowledge; (3) Self-efficacy substantially influenced perceived benefits and perceived barriers; (4) Health knowledge and social support indirectly influenced health examination behavioral intention. The preceding results can effectively increase the acceptance and use of health examination services among the public, thereby facilitating early diagnosis and treatment and ultimately reducing disease and mortality rates. PMID:27043606

  6. Interactions among hydrogeomorphology, vegetation, and nutrient biogeochemistry in floodplain ecosystems

    USGS Publications Warehouse

    Noe, G.B.

    2013-01-01

    Hydrogeomorphic, vegetative, and biogeochemical processes interact in floodplains resulting in great complexity that provides opportunities to better understand linkages among physical and biological processes in ecosystems. Floodplains and their associated river systems are structured by four dimensional gradients of hydrogeomorphology: longitudinal, lateral, vertical, and temporal components. These four dimensions create dynamic hydrologic and geomorphologic mosaics that have a large imprint on the vegetation and nutrient biogeochemistry of floodplains. Plant physiology, population dynamics, community structure, and productivity are all very responsive to floodplain hydrogeomorphology. The strength of this relationship between vegetation and hydrogeomorphology is evident in the use of vegetation as an indicator of hydrogeomorphic processes. However, vegetation also influences hydrogeomorphology by modifying hydraulics and sediment entrainment and deposition that typically stabilize geomorphic patterns. Nitrogen and phosphorus biogeochemistry commonly influence plant productivity and community composition, although productivity is not limited by nutrient availability in all floodplains. Conversely, vegetation influences nutrient biogeochemistry through direct uptake and storage as well as production of organic matter that regulates microbial biogeochemical processes. The biogeochemistries of nitrogen and phosphorus cycling are very sensitive to spatial and temporal variation in hydrogeomorphology, in particular floodplain wetness and sedimentation. The least studied interaction is the direct effect of biogeochemistry on hydrogeomorphology, but the control of nutrient availability over organic matter decomposition and thus soil permeability and elevation is likely important. Biogeochemistry also has the more documented but indirect control of hydrogeomorphology through regulation of plant biomass. In summary, the defining characteristics of floodplain ecosystems

  7. Interactions among hydrogeomorphology, vegetation, and nutrient biogeochemistry in floodplain ecosystems

    USGS Publications Warehouse

    Noe, G.B.; Shroder, John F.

    2013-01-01

    Hydrogeomorphic, vegetative, and biogeochemical processes interact in floodplains resulting in great complexity that provides opportunities to better understand linkages among physical and biological processes in ecosystems. Floodplains and their associated river systems are structured by four-dimensional gradients of hydrogeomorphology: longitudinal, lateral, vertical, and temporal components. These four dimensions create dynamic hydrologic and geomorphologic mosaics that have a large imprint on the vegetation and nutrient biogeochemistry of floodplains. Plant physiology, population dynamics, community structure, and productivity are all very responsive to floodplain hydrogeomorphology. The strength of this relationship between vegetation and hydrogeomorphology is evident in the use of vegetation as an indicator of hydrogeomorphic processes. However, vegetation also influences hydrogeomorphology by modifying hydraulics and sediment entrainment and deposition that typically stabilize geomorphic patterns. Nitrogen and phosphorus biogeochemistry commonly influence plant productivity and community composition, although productivity is not limited by nutrient availability in all floodplains. Conversely, vegetation influences nutrient biogeochemistry through direct uptake and storage as well as production of organic matter that regulates microbial biogeochemical processes. The biogeochemistries of nitrogen and phosphorus cycling are very sensitive to spatial and temporal variation in hydrogeomorphology, in particular floodplain wetness and sedimentation. The least-studied interaction is the direct effect of biogeochemistry on hydrogeomorphology, but the control of nutrient availability over organic matter decomposition and thus soil permeability and elevation is likely important. Biogeochemistry also has the more documented but indirect control of hydrogeomorphology through regulation of plant biomass. In summary, the defining characteristics of floodplain ecosystems

  8. 40 CFR 257.3-1 - Floodplains.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 26 2012-07-01 2011-07-01 true Floodplains. 257.3-1 Section 257.3-1... and Practices § 257.3-1 Floodplains. (a) Facilities or practices in floodplains shall not restrict the flow of the base flood, reduce the temporary water storage capacity of the floodplain, or result...

  9. 40 CFR 257.3-1 - Floodplains.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 25 2011-07-01 2011-07-01 false Floodplains. 257.3-1 Section 257.3-1... and Practices § 257.3-1 Floodplains. (a) Facilities or practices in floodplains shall not restrict the flow of the base flood, reduce the temporary water storage capacity of the floodplain, or result...

  10. 40 CFR 257.3-1 - Floodplains.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 26 2013-07-01 2013-07-01 false Floodplains. 257.3-1 Section 257.3-1... and Practices § 257.3-1 Floodplains. (a) Facilities or practices in floodplains shall not restrict the flow of the base flood, reduce the temporary water storage capacity of the floodplain, or result...

  11. 40 CFR 257.3-1 - Floodplains.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 24 2010-07-01 2010-07-01 false Floodplains. 257.3-1 Section 257.3-1... and Practices § 257.3-1 Floodplains. (a) Facilities or practices in floodplains shall not restrict the flow of the base flood, reduce the temporary water storage capacity of the floodplain, or result...

  12. 40 CFR 257.3-1 - Floodplains.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 25 2014-07-01 2014-07-01 false Floodplains. 257.3-1 Section 257.3-1... and Practices § 257.3-1 Floodplains. (a) Facilities or practices in floodplains shall not restrict the flow of the base flood, reduce the temporary water storage capacity of the floodplain, or result...

  13. Floodplain Modulation of Solute Fluxes from Mountainous Regions: the Amazonian Madre de Dios River Case Study

    NASA Astrophysics Data System (ADS)

    Torres, M. A.; West, A. J.; Baronas, J. J.; Ponton, C.; Clark, K. E.; Feakins, S. J.; Galy, V.

    2015-12-01

    In many large river systems, solutes released by chemical weathering in mountainous regions are transported through floodplains before being discharged into the ocean. Chemical reactions within floodplains can both add and remove solutes, significantly modulating fluxes. Despite their importance in the relationship between tectonic uplift and solute fluxes to the ocean, many aspects of floodplain processes are poorly constrained since the chemistry of large rivers is also significantly affected by the mixing between multiple tributaries, which makes the separation and quantification of floodplain processes challenging. Here we explore how floodplain processes affect a suite of major and trace elements in the Madre de Dios River system in Peru. To separate floodplain processes from conservative mixing, we developed a tributary mixing model that uses water isotopic ratios and chloride concentrations measured in each tributary and upstream and downstream of each tributary confluence for all major tributaries along a floodplain reach. The results of the tributary mixing model allow for the chemical composition of the mainstem of the Madre de Dios River to be modeled assuming completely conservative mixing. Differences between the modeled and measured chemical composition of the mainstem are then used to identify and quantify the effects of floodplain processes on different solutes. Our results show that during both the wet and dry seasons, Li is removed and Ca, Mg, and Sr are added to the dissolved load during floodplain transit. Other solutes, like Na and SO4, appear to behave conservatively during floodplain transit. Likely, the removal of Li from the dissolved load reflects the precipitation of secondary silicate minerals in the floodplain. The release of Ca, Mg, and Sr likely reflects the dissolution of detrital carbonate minerals. Our analyses also show that tributaries with Andean headwaters contribute disproportionately to solute budgets while the water budget

  14. Holocene floodplain sedimentation in Central Europe and the impact of historic mining

    NASA Astrophysics Data System (ADS)

    Raab, T.; Huerkamp, K.; Voelkel, J.

    2008-12-01

    In most parts of Europe, the Late Quaternary evolution of floodplain environments is the result of interactions between natural and human factors. Land-use changes, during the Neolithic, such as deforestation and the introduction of agriculture affected the stratigraphy of river sediments due to soil erosion on the slopes and alluvial deposition of fine-grained sediments in the floodplains. Beside agriculture mining must be also considered as an important factor controlling the Late Holocene floodplain evolution. Prehistoric and historic metal mining activities caused landscape degradation, such as vegetation clearance which increased the rate of soil erosion especially via hillslope gullying. During the Late Middle Ages, East Bavaria, Germany and the Vils River Valley in particular were one of the leading regions for the iron industry in Central Europe. Two hundred ironworks used 378 000 m3 of wood per annum allowing the production of 9000 tons of iron during the "golden age" of mining in the 15th century. Since the late 19th century the role of the iron industry in East Bavaria has decreased rapidly. The intensive historic mining activities on the Vils River floodplain should have affected the river structure as well as the fluvial dynamics, in particular via the construction of ironworks and associated weirs. Further floodplain sedimentation is thought to have been influenced by the mining-induced soil erosion occurring in the catchment and primary on the slopes. The nature and extent of these changes have not been investigated to date. Analysis of 288 percussion drillings with depths of up to 7 m and a 120 m long excavator section provide new and detailed information on the Late Pleistocene to Late Holocene floodplain evolution. The generalised sequence of the Vils River floodplain is built up of five units representing facies of different genesis (rock/saprolite, gravel, sand, loam, peat) which are identified by physical, chemical and mineralogical parameters

  15. Floodplain Lakes: Evolution and Response

    NASA Astrophysics Data System (ADS)

    Hausmann, Sonja; Hall, Roland; Gell, Peter

    2011-05-01

    PAGES International Floodplain Lakes Workshop; Fayetteville, Arkansas, 16-19 September 2010 ; Human alteration of the major rivers and floodplains of the world is a global concern because they sustain aquatic ecosystems and supply food and energy to society. When in flood stage, the influence of a river extends across the floodplain and can revitalize productive wetlands. The condition of many rivers has declined worldwide, but the degree of degradation is hard to assess due to natural variability of flow and uncertainty of baseline status. Evidence of changes over decades to millennia in river and wetland conditions, however, can be quantified from physical, chemical, and biological information archived in the accumulated sediments of floodplain lakes.

  16. The Potential for Dams to Impact Lowland Meandering River Floodplain Geomorphology

    PubMed Central

    Marren, Philip M.; Grove, James R.; Webb, J. Angus; Stewardson, Michael J.

    2014-01-01

    The majority of the world's floodplains are dammed. Although some implications of dams for riverine ecology and for river channel morphology are well understood, there is less research on the impacts of dams on floodplain geomorphology. We review studies from dammed and undammed rivers and include influences on vertical and lateral accretion, meander migration and cutoff formation, avulsion, and interactions with floodplain vegetation. The results are synthesized into a conceptual model of the effects of dams on the major geomorphic influences on floodplain development. This model is used to assess the likely consequences of eight dam and flow regulation scenarios for floodplain geomorphology. Sediment starvation downstream of dams has perhaps the greatest potential to impact on floodplain development. Such effects will persist further downstream where tributary sediment inputs are relatively low and there is minimal buffering by alluvial sediment stores. We can identify several ways in which floodplains might potentially be affected by dams, with varying degrees of confidence, including a distinction between passive impacts (floodplain disconnection) and active impacts (changes in geomorphological processes and functioning). These active processes are likely to have more serious implications for floodplain function and emphasize both the need for future research and the need for an “environmental sediment regime” to operate alongside environmental flows. PMID:24587718

  17. The potential for dams to impact lowland meandering river floodplain geomorphology.

    PubMed

    Marren, Philip M; Grove, James R; Webb, J Angus; Stewardson, Michael J

    2014-01-01

    The majority of the world's floodplains are dammed. Although some implications of dams for riverine ecology and for river channel morphology are well understood, there is less research on the impacts of dams on floodplain geomorphology. We review studies from dammed and undammed rivers and include influences on vertical and lateral accretion, meander migration and cutoff formation, avulsion, and interactions with floodplain vegetation. The results are synthesized into a conceptual model of the effects of dams on the major geomorphic influences on floodplain development. This model is used to assess the likely consequences of eight dam and flow regulation scenarios for floodplain geomorphology. Sediment starvation downstream of dams has perhaps the greatest potential to impact on floodplain development. Such effects will persist further downstream where tributary sediment inputs are relatively low and there is minimal buffering by alluvial sediment stores. We can identify several ways in which floodplains might potentially be affected by dams, with varying degrees of confidence, including a distinction between passive impacts (floodplain disconnection) and active impacts (changes in geomorphological processes and functioning). These active processes are likely to have more serious implications for floodplain function and emphasize both the need for future research and the need for an "environmental sediment regime" to operate alongside environmental flows.

  18. The potential for dams to impact lowland meandering river floodplain geomorphology.

    PubMed

    Marren, Philip M; Grove, James R; Webb, J Angus; Stewardson, Michael J

    2014-01-01

    The majority of the world's floodplains are dammed. Although some implications of dams for riverine ecology and for river channel morphology are well understood, there is less research on the impacts of dams on floodplain geomorphology. We review studies from dammed and undammed rivers and include influences on vertical and lateral accretion, meander migration and cutoff formation, avulsion, and interactions with floodplain vegetation. The results are synthesized into a conceptual model of the effects of dams on the major geomorphic influences on floodplain development. This model is used to assess the likely consequences of eight dam and flow regulation scenarios for floodplain geomorphology. Sediment starvation downstream of dams has perhaps the greatest potential to impact on floodplain development. Such effects will persist further downstream where tributary sediment inputs are relatively low and there is minimal buffering by alluvial sediment stores. We can identify several ways in which floodplains might potentially be affected by dams, with varying degrees of confidence, including a distinction between passive impacts (floodplain disconnection) and active impacts (changes in geomorphological processes and functioning). These active processes are likely to have more serious implications for floodplain function and emphasize both the need for future research and the need for an "environmental sediment regime" to operate alongside environmental flows. PMID:24587718

  19. Determinism in fish assemblages of floodplain lakes of the vastly disturbed Mississippi Alluvial Valley

    USGS Publications Warehouse

    Miranda, L.E.; Lucas, G.M.

    2004-01-01

    The Mississippi Alluvial Valley between southern Illinois and southern Louisiana contains hundreds of floodplain lakes, most of which have been adversely affected by landscape modifications used to control flooding and support agriculture. We examined fish assemblages in lakes of this region to determine whether deterministic patterns developed in relation to prominent abiotic lake characteristics and to explore whether relevant abiotic factors could be linked to specific assemblage structuring mechanisms. The distributions of 14 taxa in 29 lakes were governed primarily by two gradients that contrasted assemblages in terms of lake area, lake elongation, and water clarity. The knowledge of whether a lake was clear or turbid, large or small, and long or short helped determine fish assemblage characteristics. Abiotic factors influenced fish assemblage structures, plausibly through limitations on foraging and physiological tolerances. Determinism in assemblage organization of floodplain lakes relative to recurrence in physicochemical features has been documented for unaltered rivers. Whereas the Mississippi Alluvial Valley has been subjected to vast anthropogenic disturbances and is not a fully functional floodplain river, fish assemblages in its floodplain lakes remain deterministic and organized by the underlying factors that also dictate assemblages in unaltered rivers. In advanced stages of lake aging, fish assemblages in these lakes are expected to largely include species that thrive in turbid, shallow systems with few predators and low oxygen concentrations. The observed patterns related to physical characteristics of these lakes suggest three general conservation foci, including (1) watershed management to control erosion, (2) removal of sediments or increases in water level to alleviate depth reductions and derived detriments to water physicochemistry, and (3) management of fish populations through stockings, removals, and harvest regulations.

  20. Wetland tree transpiration modified by river-floodplain connectivity

    USGS Publications Warehouse

    Allen, Scott T; Krauss, Ken W.; Cochran, J. Wesley; King, Sammy L.; Keim, Richard F.

    2016-01-01

    Hydrologic connectivity provisions water and nutrient subsidies to floodplain wetlands and may be particularly important in floodplains with seasonal water deficits through its effects on soil moisture. In this study, we measured sapflow in 26 trees of two dominant floodplain forest species (Celtis laevigata and Quercus lyrata) at two hydrologically distinct sites in the lower White River floodplain in Arkansas, USA. Our objective was to investigate how connectivity-driven water table variations affected water use, an indicator of tree function. Meteorological variables (photosynthetically active radiation and vapor pressure deficit) were the dominant controls over water use at both sites; however, water table variations explained some site differences. At the wetter site, highest sapflow rates were during a late-season overbank flooding event, and no flood stress was apparent. At the drier site, sapflow decreased as the water table receded. The late-season flood pulse that resulted in flooding at the wetter site did not affect the water table at the drier site; accordingly, higher water use was not observed at the drier site. The species generally associated with wetter conditions (Q. lyrata) was more positively responsive to the flood pulse. Flood water subsidy lengthened the effective growing season, demonstrating ecological implications of hydrologic connectivity for alleviating water deficits that otherwise reduce function in this humid floodplain wetland.

  1. Wetland tree transpiration modified by river-floodplain connectivity

    NASA Astrophysics Data System (ADS)

    Allen, Scott T.; Krauss, Ken W.; Cochran, J. Wesley; King, Sammy L.; Keim, Richard F.

    2016-03-01

    Hydrologic connectivity provisions water and nutrient subsidies to floodplain wetlands and may be particularly important in floodplains with seasonal water deficits through its effects on soil moisture. In this study, we measured sapflow in 26 trees of two dominant floodplain forest species (Celtis laevigata and Quercus lyrata) at two hydrologically distinct sites in the lower White River floodplain in Arkansas, USA. Our objective was to investigate how connectivity-driven water table variations affected water use, an indicator of tree function. Meteorological variables (photosynthetically active radiation and vapor pressure deficit) were the dominant controls over water use at both sites; however, water table variations explained some site differences. At the wetter site, highest sapflow rates were during a late-season overbank flooding event, and no flood stress was apparent. At the drier site, sapflow decreased as the water table receded. The late-season flood pulse that resulted in flooding at the wetter site did not affect the water table at the drier site; accordingly, higher water use was not observed at the drier site. The species generally associated with wetter conditions (Q. lyrata) was more positively responsive to the flood pulse. Flood water subsidy lengthened the effective growing season, demonstrating ecological implications of hydrologic connectivity for alleviating water deficits that otherwise reduce function in this humid floodplain wetland.

  2. The importance of floodplain forests in the conservation and management of neotropical migratory birds in the Midwest

    USGS Publications Warehouse

    Knutson, M.G.; Hoover, J.P.; Klaas, E.E.; Thompson, Frank R.

    1996-01-01

    Bottomland forests of the Central Forest Region of the Upper Midwest are found primarily on the floodplains of large rivers and include at least six types of forest communities. Birds breeding in bottomland forests are affected by extensive variation in latitude, climate, hydrology, forest succession, and change caused by anthropogenic disturbances. The floodplain forest bird community differs in species composition and in relative abundance from adjacent upland habitats. High abundances of some species are found in the floodplain and some species, such as the prothonotary warbler, brown creeper, yellow-billed cuckoo, yellow-bellied sapsucker, and great crested flycatcher, show a clear preference for floodplain forests. Studies of nesting success indicate that, for some species, nest success may be higher in the floodplain than in the uplands. Floodplain birds face threats due to large-scale loss of floodplain forest habitat. Conservation efforts should focus on restoring degraded floodplains by maintaining high tree species diversity and wide corridors. To accomplish this, the underlying hydrodynamics which support a diverse floodplain forest habitat may need to be restored. Large, contiguous tracts of floodplain and upland forests should be maintained where they exist and restored in other locations. This will provide some high quality habitat for area-sensitive neotropical migratory birds (NTMBs) in agricultural landscapes where small, scattered forest fragments are the rule. Future research efforts should examine the importance of floodplain forests in maintaining populations of neotropical migrants, especially birds experiencing population declines in adjacent uplands.

  3. Understanding the behavior of floodplains as human-water systems

    NASA Astrophysics Data System (ADS)

    Di Baldassarre, G.; Brandimarte, L.

    2012-12-01

    Floodplains are among the most valuable ecosystems for supporting biodiversity and providing services to the environment. Moreover, they are home of approximately one-sixth of the world population as they offer favorable conditions for economic development. As a result, flood disasters currently affect more than 100 million people a year. Sadly, flood losses and fatalities are expected to increase further in many countries because of population growth as well as changes in land use and climate. Given the relevance of floodplain systems, a number of social scientists have examined how the frequency and severity of flooding often determine whether human development in floodplains is desirable or not. Meanwhile, many earth scientists have investigated the impact of human activities (e.g. land-use changes, urbanization, river training) on the frequency and magnitude of floods. In fact, as human activities change the frequency of flooding, the frequency of flooding affects human developments in floodplain areas. Yet, these dynamic interactions between floods and societies and the associated feedback mechanisms remain largely unexplored and poorly understood. As a result, we typically consider humans as external forcing (or boundary condition) without representing the feedback loops and our prediction of future trajectories are therefore extremely limited. This presentation shows a first attempt to understand the behavior of floodplains as coupled human-water systems. In particular, we analyzed a number of long time series of hydrological and population data in the Po River Basin (Italy) to explore the feedback mechanisms, reciprocal effects, surprises, and threshold mechanisms, taking place in floodplain systems. The outcomes of the study enable a better understanding of how the occurrences of floods shape human developments while, at the same time, human activities shape the magnitude and frequency of floods. The presentation also discusses the opportunities offered by

  4. Measuring floodplain spatial patterns using continuous surface metrics at multiple scales

    USGS Publications Warehouse

    Murray Scown,; Martin Thoms,; DeJager, Nathan R.

    2015-01-01

    Interactions between fluvial processes and floodplain ecosystems occur upon a floodplain surface that is often physically complex. Spatial patterns in floodplain topography have only recently been quantified over multiple scales, and discrepancies exist in how floodplain surfaces are perceived to be spatially organised. We measured spatial patterns in floodplain topography for pool 9 of the Upper Mississippi River, USA, using moving window analyses of eight surface metrics applied to a 1 × 1 m2 DEM over multiple scales. The metrics used were Range, SD, Skewness, Kurtosis, CV, SDCURV,Rugosity, and Vol:Area, and window sizes ranged from 10 to 1000 m in radius. Surface metric values were highly variable across the floodplain and revealed a high degree of spatial organisation in floodplain topography. Moran's I correlograms fit to the landscape of each metric at each window size revealed that patchiness existed at nearly all window sizes, but the strength and scale of patchiness changed within window size, suggesting that multiple scales of patchiness and patch structure exist in the topography of this floodplain. Scale thresholds in the spatial patterns were observed, particularly between the 50 and 100 m window sizes for all surface metrics and between the 500 and 750 m window sizes for most metrics. These threshold scales are ~ 15–20% and 150% of the main channel width (1–2% and 10–15% of the floodplain width), respectively. These thresholds may be related to structuring processes operating across distinct scale ranges. By coupling surface metrics, multi-scale analyses, and correlograms, quantifying floodplain topographic complexity is possible in ways that should assist in clarifying how floodplain ecosystems are structured.

  5. Evaluating the Influence of Floodplain-filling Styles on Channel-belt Stacking and Basin-scale Fluvial Architecture

    NASA Astrophysics Data System (ADS)

    Chamberlin, E.; Hajek, E. A.

    2014-12-01

    Recent work in modern and ancient systems has shown a range of characteristic floodplain sedimentation patterns acting over a range of temporal and spatial scales. In aggradational fluvial systems floodplain sedimentation style influences where rivers relocate during avulsion, which in turn influences the distribution of channel-belt sandstones in stratigraphy over long timescales. Exploring the link between floodplain-sedimentation patterns and avulsions is therefore important for both predicting stratigraphic architecture and using stratigraphy to interpret paleo-floodplain sedimentation dynamics. Here we use an object-based model of basin filling to explore how different floodplain aggradation styles (including both uniform and exponential decay) affect the stratigraphic preservation of three different avulsion patterns: random (channels are equally likely to relocate anywhere on the floodplain), compensational (channels relocate to the lowest point on the floodplain), and clustered (channels relocate to a point near the previous channel position). Preliminary modeling results suggest that only clustered avulsion patterns are identifiable under uniform floodplain aggradation conditions, but that different avulsion patterns generate unique sand-body distributions under exponential floodplain sedimentation. This suggests that floodplain-aggradation styles influence how well we can interpret paleo-avulsion patterns in ancient deposits. We apply these insights to the Paleocene-Eocene Wasatch Formation in western Colorado to explore the relationship between preserved floodplain deposits and basin-scale sand-body architecture. We compare proxies for paleo-floodplain-aggradation patterns (including paleosol development, lateral continuity of paleosol horizons, and occurrence and distribution of splays) in three different members with quantitative metrics of channel-body organization at both sand-body and outcrop scales. Changes in floodplain deposits and sand

  6. Dams, floodplain land use, and riparian forest conservation in the semiarid Upper Colorado River Basin, USA

    USGS Publications Warehouse

    Andersen, D.C.; Cooper, D.J.; Northcott, K.

    2007-01-01

    Land and water resource development can independently eliminate riparian plant communities, including Fremont cottonwood forest (CF), a major contributor to ecosystem structure and functioning in semiarid portions of the American Southwest. We tested whether floodplain development was linked to river regulation in the Upper Colorado River Basin (UCRB) by relating the extent of five developed land-cover categories as well as CF and other natural vegetation to catchment reservoir capacity, changes in total annual and annual peak discharge, and overall level of mainstem hydrologic alteration (small, moderate, or large) in 26 fourth-order subbasins. We also asked whether CF appeared to be in jeopardy at a regional level. We classified 51% of the 57,000 ha of alluvial floodplain examined along >2600 km of mainstem rivers as CF and 36% as developed. The proportion developed was unrelated to the level of mainstem hydrologic alteration. The proportion classified as CF was also independent of the level of hydrologic alteration, a result we attribute to confounding effects from development, the presence of time lags, and contrasting effects from flow alteration in different subbasins. Most CF (68% by area) had a sparse canopy (???5% cover), and stands with >50% canopy cover occupied <1% of the floodplain in 15 subbasins. We suggest that CF extent in the UCRB will decline markedly in the future, when the old trees on floodplains now disconnected from the river die and large areas change from CF to non-CF categories. Attention at a basinwide scale to the multiple factors affecting cottonwood patch dynamics is needed to assure conservation of these riparian forests. ?? 2007 Springer Science+Business Media, LLC.

  7. Satellite multispectral data for improved floodplain roughness modelling

    NASA Astrophysics Data System (ADS)

    Forzieri, Giovanni; Degetto, Massimo; Righetti, Maurizio; Castelli, Fabio; Preti, Federico

    2011-09-01

    SummaryRiparian vegetation plays a crucial role on affecting the floodplain hydraulic roughness, which in turn significantly influences the dynamics of flood waves. This paper explores the potential accuracies of retrieving vegetation hydrodynamic parameters through satellite multispectral data. The method is focused on estimation of vegetation height ( h g) and flexural rigidity ( MEI) for herbaceous patterns and of plant density ( M), tree height ( h), stem diameter ( Ds), crown base height ( cbh) and crown diameter ( Dc) of high-forest ( hf) and coppice ( cop) consociations for arboreal and shrub patterns. The method is organized in four sequential steps: (1) classification procedure of riparian corridor; (2) land cover-based Principal Component Analysis of spectral channels; (3) explorative analysis of correlation structure between principal components and biomechanical properties and (4) model identification/estimation/validation for floodplain roughness parameterization. To capture the hydrodynamic impacts of stiff/flexible vegetation, a GIS hydrodynamic model has been coupled with a flow resistance external routine that estimates the hydraulic roughness by using simulated water stages and the remote sensing-derived hydrodynamic parameters. The procedure is tested along a 3-km reach of the Avisio river (Trentino Alto Adige, Italy) by comparing extended field surveys and a synchronous SPOT-5 multispectral image acquired on 28/08/2004. Results showed significant correlation values between spectral-derived information and hydrodynamic parameters. Predictive models provided high coefficients of determination, especially for mixed arboreal and shrub land covers. The generated structural parameter maps represent spatially explicit data layers that can be used as inputs to hydrodynamic models to analyze flow resistance effects in different submergence conditions of vegetation. The hydraulic modelling results showed that the new method is able to provide accurate

  8. Gravel-bed river floodplains are the ecological nexus of glaciated mountain landscapes.

    PubMed

    Hauer, F Richard; Locke, Harvey; Dreitz, Victoria J; Hebblewhite, Mark; Lowe, Winsor H; Muhlfeld, Clint C; Nelson, Cara R; Proctor, Michael F; Rood, Stewart B

    2016-06-01

    Gravel-bed river floodplains in mountain landscapes disproportionately concentrate diverse habitats, nutrient cycling, productivity of biota, and species interactions. Although stream ecologists know that river channel and floodplain habitats used by aquatic organisms are maintained by hydrologic regimes that mobilize gravel-bed sediments, terrestrial ecologists have largely been unaware of the importance of floodplain structures and processes to the life requirements of a wide variety of species. We provide insight into gravel-bed rivers as the ecological nexus of glaciated mountain landscapes. We show why gravel-bed river floodplains are the primary arena where interactions take place among aquatic, avian, and terrestrial species from microbes to grizzly bears and provide essential connectivity as corridors for movement for both aquatic and terrestrial species. Paradoxically, gravel-bed river floodplains are also disproportionately unprotected where human developments are concentrated. Structural modifications to floodplains such as roads, railways, and housing and hydrologic-altering hydroelectric or water storage dams have severe impacts to floodplain habitat diversity and productivity, restrict local and regional connectivity, and reduce the resilience of both aquatic and terrestrial species, including adaptation to climate change. To be effective, conservation efforts in glaciated mountain landscapes intended to benefit the widest variety of organisms need a paradigm shift that has gravel-bed rivers and their floodplains as the central focus and that prioritizes the maintenance or restoration of the intact structure and processes of these critically important systems throughout their length and breadth.

  9. Gravel-bed river floodplains are the ecological nexus of glaciated mountain landscapes

    PubMed Central

    Hauer, F. Richard; Locke, Harvey; Dreitz, Victoria J.; Hebblewhite, Mark; Lowe, Winsor H.; Muhlfeld, Clint C.; Nelson, Cara R.; Proctor, Michael F.; Rood, Stewart B.

    2016-01-01

    Gravel-bed river floodplains in mountain landscapes disproportionately concentrate diverse habitats, nutrient cycling, productivity of biota, and species interactions. Although stream ecologists know that river channel and floodplain habitats used by aquatic organisms are maintained by hydrologic regimes that mobilize gravel-bed sediments, terrestrial ecologists have largely been unaware of the importance of floodplain structures and processes to the life requirements of a wide variety of species. We provide insight into gravel-bed rivers as the ecological nexus of glaciated mountain landscapes. We show why gravel-bed river floodplains are the primary arena where interactions take place among aquatic, avian, and terrestrial species from microbes to grizzly bears and provide essential connectivity as corridors for movement for both aquatic and terrestrial species. Paradoxically, gravel-bed river floodplains are also disproportionately unprotected where human developments are concentrated. Structural modifications to floodplains such as roads, railways, and housing and hydrologic-altering hydroelectric or water storage dams have severe impacts to floodplain habitat diversity and productivity, restrict local and regional connectivity, and reduce the resilience of both aquatic and terrestrial species, including adaptation to climate change. To be effective, conservation efforts in glaciated mountain landscapes intended to benefit the widest variety of organisms need a paradigm shift that has gravel-bed rivers and their floodplains as the central focus and that prioritizes the maintenance or restoration of the intact structure and processes of these critically important systems throughout their length and breadth. PMID:27386570

  10. Gravel-bed river floodplains are the ecological nexus of glaciated mountain landscapes

    USGS Publications Warehouse

    Hauer, F. Richard; Locke, Harvey; Dreitz, Victoria; Hebblewhite, Mark; Lowe, Winsor; Muhlfeld, Clint C.; Nelson, Cara; Proctor, Michael F; Rood, Stewart B.

    2016-01-01

    Gravel-bed river floodplains in mountain landscapes disproportionately concentrate diverse habitats, nutrient cycling, productivity of biota, and species interactions. Although stream ecologists know that river channel and floodplain habitats used by aquatic organisms are maintained by hydrologic regimes that mobilize gravel-bed sediments, terrestrial ecologists have largely been unaware of the importance of floodplain structures and processes to the life requirements of a wide variety of species. We provide insight into gravel-bed rivers as the ecological nexus of glaciated mountain landscapes. We show why gravel-bed river floodplains are the primary arena where interactions take place among aquatic, avian, and terrestrial species from microbes to grizzly bears and provide essential connectivity as corridors for movement for both aquatic and terrestrial species. Paradoxically, gravel-bed river floodplains are also disproportionately unprotected where human developments are concentrated. Structural modifications to floodplains such as roads, railways, and housing and hydrologicaltering hydroelectric or water storage dams have severe impacts to floodplain habitat diversity and productivity, restrict local and regional connectivity, and reduce the resilience of both aquatic and terrestrial species, including adaptation to climate change. To be effective, conservation efforts in glaciated mountain landscapes intended to benefit the widest variety of organisms need a paradigm shift that has gravel-bed rivers and their floodplains as the central focus and that prioritizes the maintenance or restoration of the intact structure and processes of these critically important systems throughout their length and breadth.

  11. Gravel-bed river floodplains are the ecological nexus of glaciated mountain landscapes.

    PubMed

    Hauer, F Richard; Locke, Harvey; Dreitz, Victoria J; Hebblewhite, Mark; Lowe, Winsor H; Muhlfeld, Clint C; Nelson, Cara R; Proctor, Michael F; Rood, Stewart B

    2016-06-01

    Gravel-bed river floodplains in mountain landscapes disproportionately concentrate diverse habitats, nutrient cycling, productivity of biota, and species interactions. Although stream ecologists know that river channel and floodplain habitats used by aquatic organisms are maintained by hydrologic regimes that mobilize gravel-bed sediments, terrestrial ecologists have largely been unaware of the importance of floodplain structures and processes to the life requirements of a wide variety of species. We provide insight into gravel-bed rivers as the ecological nexus of glaciated mountain landscapes. We show why gravel-bed river floodplains are the primary arena where interactions take place among aquatic, avian, and terrestrial species from microbes to grizzly bears and provide essential connectivity as corridors for movement for both aquatic and terrestrial species. Paradoxically, gravel-bed river floodplains are also disproportionately unprotected where human developments are concentrated. Structural modifications to floodplains such as roads, railways, and housing and hydrologic-altering hydroelectric or water storage dams have severe impacts to floodplain habitat diversity and productivity, restrict local and regional connectivity, and reduce the resilience of both aquatic and terrestrial species, including adaptation to climate change. To be effective, conservation efforts in glaciated mountain landscapes intended to benefit the widest variety of organisms need a paradigm shift that has gravel-bed rivers and their floodplains as the central focus and that prioritizes the maintenance or restoration of the intact structure and processes of these critically important systems throughout their length and breadth. PMID:27386570

  12. Structure and Affect: The Influence of Social Structure on Affective Meaning in American Kinship

    ERIC Educational Resources Information Center

    Malone, Martin J.

    2004-01-01

    Structural variables differentiating kinship identities, such as sex, generation, and type of relationship (lineal, collateral, conjugal), are reflected in sentiments about family identities. In particular, componential variations in kinship terms predict Evaluation, Potency, and Activity ratings of the terms fairly accurately. Between 44 and 92…

  13. 40 CFR 258.11 - Floodplains.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 25 2014-07-01 2014-07-01 false Floodplains. 258.11 Section 258.11... SOLID WASTE LANDFILLS Location Restrictions § 258.11 Floodplains. (a) Owners or operators of new MSWLF units, existing MSWLF units, and lateral expansions located in 100-year floodplains must...

  14. 7 CFR 624.10 - Floodplain easements.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 6 2013-01-01 2013-01-01 false Floodplain easements. 624.10 Section 624.10..., DEPARTMENT OF AGRICULTURE WATER RESOURCES EMERGENCY WATERSHED PROTECTION § 624.10 Floodplain easements. (a) General. NRCS may purchase floodplain easements as an emergency measure. NRCS will only purchase...

  15. 7 CFR 624.10 - Floodplain easements.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 6 2012-01-01 2012-01-01 false Floodplain easements. 624.10 Section 624.10..., DEPARTMENT OF AGRICULTURE WATER RESOURCES EMERGENCY WATERSHED PROTECTION § 624.10 Floodplain easements. (a) General. NRCS may purchase floodplain easements as an emergency measure. NRCS will only purchase...

  16. 40 CFR 257.8 - Floodplains.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 26 2013-07-01 2013-07-01 false Floodplains. 257.8 Section 257.8... Location Restrictions § 257.8 Floodplains. (a) Owners or operators of new units, existing units, and lateral expansions located in 100-year floodplains must demonstrate that the unit will not restrict...

  17. 40 CFR 257.8 - Floodplains.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 26 2012-07-01 2011-07-01 true Floodplains. 257.8 Section 257.8... Location Restrictions § 257.8 Floodplains. (a) Owners or operators of new units, existing units, and lateral expansions located in 100-year floodplains must demonstrate that the unit will not restrict...

  18. 32 CFR 644.320 - Floodplain management.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 32 National Defense 4 2010-07-01 2010-07-01 true Floodplain management. 644.320 Section 644.320... ESTATE HANDBOOK Disposal § 644.320 Floodplain management. The requirements of Executive Order 11988, Floodplain Management, 42 FR 26951, (24 May 1977) and its implementation will be outlined in subpart H (to...

  19. 40 CFR 257.8 - Floodplains.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 24 2010-07-01 2010-07-01 false Floodplains. 257.8 Section 257.8... Location Restrictions § 257.8 Floodplains. (a) Owners or operators of new units, existing units, and lateral expansions located in 100-year floodplains must demonstrate that the unit will not restrict...

  20. 40 CFR 258.11 - Floodplains.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 26 2013-07-01 2013-07-01 false Floodplains. 258.11 Section 258.11... SOLID WASTE LANDFILLS Location Restrictions § 258.11 Floodplains. (a) Owners or operators of new MSWLF units, existing MSWLF units, and lateral expansions located in 100-year floodplains must...

  1. 32 CFR 644.320 - Floodplain management.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 32 National Defense 4 2011-07-01 2011-07-01 false Floodplain management. 644.320 Section 644.320... ESTATE HANDBOOK Disposal § 644.320 Floodplain management. The requirements of Executive Order 11988, Floodplain Management, 42 FR 26951, (24 May 1977) and its implementation will be outlined in subpart H (to...

  2. 7 CFR 624.10 - Floodplain easements.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 6 2011-01-01 2011-01-01 false Floodplain easements. 624.10 Section 624.10..., DEPARTMENT OF AGRICULTURE WATER RESOURCES EMERGENCY WATERSHED PROTECTION § 624.10 Floodplain easements. (a) General. NRCS may purchase floodplain easements as an emergency measure. NRCS will only purchase...

  3. 32 CFR 644.320 - Floodplain management.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 32 National Defense 4 2014-07-01 2013-07-01 true Floodplain management. 644.320 Section 644.320... ESTATE HANDBOOK Disposal § 644.320 Floodplain management. The requirements of Executive Order 11988, Floodplain Management, 42 FR 26951, (24 May 1977) and its implementation will be outlined in subpart H (to...

  4. 7 CFR 624.10 - Floodplain easements.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 6 2014-01-01 2014-01-01 false Floodplain easements. 624.10 Section 624.10..., DEPARTMENT OF AGRICULTURE WATER RESOURCES EMERGENCY WATERSHED PROTECTION § 624.10 Floodplain easements. (a) General. NRCS may purchase floodplain easements as an emergency measure. NRCS will only purchase...

  5. 40 CFR 258.11 - Floodplains.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 25 2011-07-01 2011-07-01 false Floodplains. 258.11 Section 258.11... SOLID WASTE LANDFILLS Location Restrictions § 258.11 Floodplains. (a) Owners or operators of new MSWLF units, existing MSWLF units, and lateral expansions located in 100-year floodplains must...

  6. 32 CFR 644.320 - Floodplain management.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 32 National Defense 4 2013-07-01 2013-07-01 false Floodplain management. 644.320 Section 644.320... ESTATE HANDBOOK Disposal § 644.320 Floodplain management. The requirements of Executive Order 11988, Floodplain Management, 42 FR 26951, (24 May 1977) and its implementation will be outlined in subpart H (to...

  7. 32 CFR 644.320 - Floodplain management.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 32 National Defense 4 2012-07-01 2011-07-01 true Floodplain management. 644.320 Section 644.320... ESTATE HANDBOOK Disposal § 644.320 Floodplain management. The requirements of Executive Order 11988, Floodplain Management, 42 FR 26951, (24 May 1977) and its implementation will be outlined in subpart H (to...

  8. 40 CFR 258.11 - Floodplains.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 26 2012-07-01 2011-07-01 true Floodplains. 258.11 Section 258.11... SOLID WASTE LANDFILLS Location Restrictions § 258.11 Floodplains. (a) Owners or operators of new MSWLF units, existing MSWLF units, and lateral expansions located in 100-year floodplains must...

  9. 40 CFR 257.8 - Floodplains.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 25 2011-07-01 2011-07-01 false Floodplains. 257.8 Section 257.8... Location Restrictions § 257.8 Floodplains. (a) Owners or operators of new units, existing units, and lateral expansions located in 100-year floodplains must demonstrate that the unit will not restrict...

  10. 40 CFR 257.8 - Floodplains.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 25 2014-07-01 2014-07-01 false Floodplains. 257.8 Section 257.8... Location Restrictions § 257.8 Floodplains. (a) Owners or operators of new units, existing units, and lateral expansions located in 100-year floodplains must demonstrate that the unit will not restrict...

  11. 7 CFR 624.10 - Floodplain easements.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 6 2010-01-01 2010-01-01 false Floodplain easements. 624.10 Section 624.10..., DEPARTMENT OF AGRICULTURE WATER RESOURCES EMERGENCY WATERSHED PROTECTION § 624.10 Floodplain easements. (a) General. NRCS may purchase floodplain easements as an emergency measure. NRCS will only purchase...

  12. An index of floodplain surface complexity

    USGS Publications Warehouse

    Scown, Murray W.; Thoms, Martin C.; DeJager, Nathan R.

    2016-01-01

    Floodplain surface topography is an important component of floodplain ecosystems. It is the primary physical template upon which ecosystem processes are acted out, and complexity in this template can contribute to the high biodiversity and productivity of floodplain ecosystems. There has been a limited appreciation of floodplain surface complexity because of the traditional focus on temporal variability in floodplains as well as limitations to quantifying spatial complexity. An index of floodplain surface complexity (FSC) is developed in this paper and applied to eight floodplains from different geographic settings. The index is based on two key indicators of complexity, variability in surface geometry (VSG) and the spatial organisation of surface conditions (SPO), and was determined at three sampling scales. FSC, VSG, and SPO varied between the eight floodplains and these differences depended upon sampling scale. Relationships between these measures of spatial complexity and seven geomorphological and hydrological drivers were investigated. There was a significant decline in all complexity measures with increasing floodplain width, which was explained by either a power, logarithmic, or exponential function. There was an initial rapid decline in surface complexity as floodplain width increased from 1.5 to 5 km, followed by little change in floodplains wider than 10 km. VSG also increased significantly with increasing sediment yield. No significant relationships were determined between any of the four hydrological variables and floodplain surface complexity.

  13. Evaluating the effects of local floodplain management policies on property owner behavior

    NASA Astrophysics Data System (ADS)

    Bollens, Scott A.; Kaiser, Edward J.; Burby, Raymond J.

    1988-05-01

    Floodplain management programs have been adopted by more than 85% of local governments in the nation with designated flood hazard areas. Yet, there has been little evaluation of the influence of floodplain policies on private sector decisions. This article examines the degree to which riverine floodplain management affects purchase and mitigation decisions made by owners of developed floodplain property in ten selected cities in the United States. We find that the stringency of such policies does not lessen floodplain property buying because of the overriding importance of site amenity factors. Indeed, flood protection measures incorporated into development projects appear to add to the attractiveness of floodplain location by increasing the perceived safety from the hazard. Property owner responses to the flood hazard after occupancy involve political action more often than individual on-site mitigation. Floodplain programs only minimally encourage on-site mitigation by the owner because most owners have not experienced a flood and many are unaware of the flood threat. It is suggested that floodplain programs will be more effective in meeting their objectives if they are directed at intervention points earlier in the land conversion process.

  14. Trace metal behaviour in estuarine and riverine floodplain soils and sediments: a review.

    PubMed

    Du Laing, G; Rinklebe, J; Vandecasteele, B; Meers, E; Tack, F M G

    2009-06-15

    This paper reviews the factors affecting trace metal behaviour in estuarine and riverine floodplain soils and sediments. Spatial occurrence of processes affecting metal mobility and availability in floodplains are largely determined by the topography. At the oxic-anoxic interface and in the anoxic layers of floodplain soils, especially redox-sensitive processes occur, which mainly result in the inclusion of metals in precipitates or the dissolution of metal-containing precipitates. Kinetics of these processes are of great importance for these soils as the location of the oxic-anoxic interface is subject to change due to fluctuating water table levels. Other important processes and factors affecting metal mobility in floodplain soils are adsorption/desorption processes, salinity, the presence of organic matter, sulphur and carbonates, pH and plant growth. Many authors report highly significant correlations between cation exchange capacity, clay or organic matter contents and metal contents in floodplain soils. Iron and manganese (hydr)oxides were found to be the main carriers for Cd, Zn and Ni under oxic conditions, whereas the organic fraction was most important for Cu. The mobility and availability of metals in a floodplain soil can be significantly reduced by the formation of metal sulphide precipitates under anoxic conditions. Ascending salinity in the flood water promotes metal desorption from the floodplain soil in the absence of sulphides, hence increases total metal concentrations in the water column. The net effect of the presence of organic matter can either be a decrease or an increase in metal mobility, whereas the presence of carbonates in calcareous floodplain soils or sediments constitutes an effective buffer against a pH decrease. Moreover, carbonates may also directly precipitate metals. Plants can affect the metal mobility in floodplain soils by oxidising their rhizosphere, taking up metals, excreting exudates and stimulating the activity of

  15. Floodplain Formation and Cottonwood Colonization Patterns on the Willamette River, Oregon, USA.

    PubMed

    Dykaar; Wigington

    2000-01-01

    / Using a series of aerial photographs taken between 1936 and 1996, we trace coevolution of floodplain and riparian forest on the Willamette River. Within-channel barforms appear to be the predominant incipient floodplain landform and habitat for primary succession. Interlinked development of bar(s) and erosion of near banks, filling of channels, and establishment and growth of cottonwoods and willows results in coalescence with older floodplain. Sizeand internal structure of riparian forest patches reflect evolution of underlying barforms or channel beds. Floodplain matures as the active channel migrates away by repetition of the bar formation and near-bank erosion process, or is progressively abandoned by infilling and/or constriction with a bar. Other parts of the floodplain are recycled as eroding banks provide the coarse sediment and large woody debris for building new bars. A multichannel planform is maintained as building bars split flow; channels lengthen as bars and islands join into larger assemblages. Avulsion appears to cut new channels only short distances. Given the central role of bars and islands in building new floodplain habitat, we identify their area as a geomorphic indicator of river-floodplain integrity. We measure an 80% decline in bar and island area between 1910 and 1988 within a 22-km section. Dams, riprap, logging, and gravel mining may all be contributing to diminished bar formation rates. Removing obstacles to natural riparian forest creation mechanisms is necessary to regenerate the river-floodplain system and realize its productive potential. PMID:10552104

  16. Reservoir floodplains support distinct fish assemblages

    USGS Publications Warehouse

    Miranda, Leandro E.; Wigen, S. L.; Dagel, Jonah D.

    2014-01-01

    Reservoirs constructed on floodplain rivers are unique because the upper reaches of the impoundment may include extensive floodplain environments. Moreover, reservoirs that experience large periodic water level fluctuations as part of their operational objectives seasonally inundate and dewater floodplains in their upper reaches, partly mimicking natural inundations of river floodplains. In four flood control reservoirs in Mississippi, USA, we explored the dynamics of connectivity between reservoirs and adjacent floodplains and the characteristics of fish assemblages that develop in reservoir floodplains relative to those that develop in reservoir bays. Although fish species richness in floodplains and bays were similar, species composition differed. Floodplains emphasized fish species largely associated with backwater shallow environments, often resistant to harsh environmental conditions. Conversely, dominant species in bays represented mainly generalists that benefit from the continuous connectivity between the bay and the main reservoir. Floodplains in the study reservoirs provided desirable vegetated habitats at lower water level elevations, earlier in the year, and more frequently than in bays. Inundating dense vegetation in bays requires raising reservoir water levels above the levels required to reach floodplains. Therefore, aside from promoting distinct fish assemblages within reservoirs and helping promote diversity in regulated rivers, reservoir floodplains are valued because they can provide suitable vegetated habitats for fish species at elevations below the normal pool, precluding the need to annually flood upland vegetation that would inevitably be impaired by regular flooding. Published 2013. This article is a U.S. Government work and is in the public domain in the USA.

  17. Ice cream structural elements that affect melting rate and hardness.

    PubMed

    Muse, M R; Hartel, R W

    2004-01-01

    Statistical models were developed to reveal which structural elements of ice cream affect melting rate and hardness. Ice creams were frozen in a batch freezer with three types of sweetener, three levels of the emulsifier polysorbate 80, and two different draw temperatures to produce ice creams with a range of microstructures. Ice cream mixes were analyzed for viscosity, and finished ice creams were analyzed for air cell and ice crystal size, overrun, and fat destabilization. The ice phase volume of each ice cream were calculated based on the freezing point of the mix. Melting rate and hardness of each hardened ice cream was measured and correlated with the structural attributes by using analysis of variance and multiple linear regression. Fat destabilization, ice crystal size, and the consistency coefficient of the mix were found to affect the melting rate of ice cream, whereas hardness was influenced by ice phase volume, ice crystal size, overrun, fat destabilization, and the rheological properties of the mix.

  18. Multiple effects of hydrological connectivity on floodplain processes in human modified river systems

    NASA Astrophysics Data System (ADS)

    Hein, Thomas; Bondar-Kunze, Elisabeth; Preiner, Stefan; Reckendorfer, Walter; Tritthart, Michael; Weigelhofer, Gabriele; Welti, Nina

    2014-05-01

    Floodplain and riparian ecosystems provide multiple functions and services of importance for human well-being and are of strategic importance for different sectors at catchment scale. Especially floodplains in the vicinity of urban areas can be areas of conflicting interests ranging from different land use types, flood water retention, drinking water production and recreation to conservation of last remnants of former riverine landscape, as it is the case in floodplains in the Danube Nationalpark downstream Vienna. Many of these ecosystem functions and services are controlled by the exchange conditions between river main channel and floodplain systems, the hydrological connectivity. At the same time these systems have been highly altered and especially the connectivity has been severely impaired. Thus, far ranging effects of changes in hydrological connectivity at various levels can be expected in altered floodplain systems. The aim of this presentation is to explore the complex control of different ecosystem functions and associated services by different parameters of hydrological connectivity, ranging from nutrient, sediment and matter dynamics and biodiversity aspects. Increasing connectivity will be shown to impact microbial dynamics, sediment-water interactions, carbon dynamics and trophic conditions, thus affecting the fundamental functions of particular floodplain systems at various spatial and temporal scales. Based on these changes also the provision of ecosystem services of floodplains is affected. The results clearly show that hydrological connectivity needs to be considered in a sustainable management approach.

  19. Silicified structures affect leaf optical properties in grasses and sedge.

    PubMed

    Klančnik, Katja; Vogel-Mikuš, Katarina; Gaberščik, Alenka

    2014-01-01

    Silicon (Si) is an important structural element that can accumulate at high concentrations in grasses and sedges, and therefore Si structures might affect the optical properties of the leaves. To better understand the role of Si in light/leaf interactions in species rich in Si, we examined the total Si and silica phytoliths, the biochemical and morphological leaf properties, and the reflectance and transmittance spectra in grasses (Phragmites australis, Phalaris arundinacea, Molinia caerulea, Deschampsia cespitosa) and sedge (Carex elata). We show that these grasses contain >1% phytoliths per dry mass, while the sedge contains only 0.4%. The data reveal the variable leaf structures of these species and significant differences in the amount of Si and phytoliths between developing and mature leaves within each species and between grasses and sedge, with little difference seen among the grass species. Redundancy analysis shows the significant roles of the different near-surface silicified leaf structures (e.g., prickle hairs, cuticle, epidermis), phytoliths and Si contents, which explain the majority of the reflectance and transmittance spectra variability. The amount of explained variance differs between mature and developing leaves. The transmittance spectra are also significantly affected by chlorophyll a content and calcium levels in the leaf tissue.

  20. Abundance and biomass responses of microbial food web components to hydrology and environmental gradients within a floodplain of the River Danube.

    PubMed

    Palijan, Goran

    2012-07-01

    This study investigated the relationships of time-dependent hydrological variability and selected microbial food web components. Samples were collected monthly from the Kopački Rit floodplain in Croatia, over a period of 19 months, for analysis of bacterioplankton abundance, cell size and biomass; abundance of heterotrophic nanoflagellates and nanophytoplankton; and concentration of chlorophyll a. Similar hydrological variability at different times of the year enabled partition of seasonal effects from hydrological changes on microbial community properties. The results suggested that, unlike some other studies investigating sites with different connectivity, bacterioplankton abundance, and phytoplankton abundance and biomass increased during lentic conditions. At increasing water level, nanophytoplankton showed lower sensitivity to disturbance in comparison with total phytoplankton biomass: this could prolong autotrophic conditions within the floodplain. Bacterioplankton biomass, unlike phytoplankton, was not impacted by hydrology. The bacterial biomass less affected by hydrological changes can be an important additional food component for the floodplain food web. The results also suggested a mechanism controlling bacterial cell size independent of hydrology, as bacterial cell size was significantly decreased as nanoflagellate abundance increased. Hydrology, regardless of seasonal sucession, has the potential to structure microbial food webs, supporting microbial development during lentic conditions. Conversely, other components appear unaffected by hydrology or may be more strongly controlled by biotic interactions. This research, therefore, adds to understanding on microbial food web interactions in the context of flood and flow pulses in river-floodplain ecosystems.

  1. Hydraulic analysis of measures for flood mitigation in floodplain

    NASA Astrophysics Data System (ADS)

    Valentova, J.; Valenta, P.; Weyskrabova, L.; Dostal, T.

    2012-04-01

    The question of possible flood control and flood mitigation measures and their effects is still challenging. While the effect of purely technical flood control measures such as dams or levees is sufficiently described by using any of widely spread or more specific models, the effectiveness of close-to-nature ones (river restoration, appropriate land use, landscape structure regeneration, etc.) is not adequately verified and quantified. On that account, the benefits and feasibility of integration of the natural potential of floodplains to absorb and transform flood wave is being discussed. In addition, there are many side benefits of close-to-nature measures which are hard to evaluate and include into decision making processes. This contribution presents a part of the study related to river and floodplain restoration and revitalization measures in catchments and their flood-control effect. In the study the possibilities of using one-dimensional (HEC-RAS) and two-dimensional hydraulic mathematical models (FAST2D, DIFEM2D) of steady and unsteady flow for estimation of transformation effects of a floodplain were compared. The comparison of used models was made with respect to computed results and also to the availability of input data, mathematical stability, processes and accuracy demands and time requirements. The above mentioned methods of hydraulic modelling were applied to three case study localities in the Czech Republic. The parts of river channels and their floodplain differ in terms of morphology, river channel form and training situation and land-use. Case study areas were selected to represent the main types of floodplains within the Czech Republic for their further classification related to flood wave transformation potential. The transformation effect is compared not only for the natural state of the floodplain, but also for various theoretical scenarios in each locality. Keywords Hydraulic modelling, flood control, floodplain, storage capacity, river

  2. Affective journeys: the emotional structuring of medical tourism in India.

    PubMed

    Solomon, Harris

    2011-04-01

    This paper examines the grid of sentiment that structures medical travel to India. In contrast to studies that render emotion as ancillary, the paper argues that affect is fundamental to medical travel's ability to ease the linked somatic, emotional, financial, and political injuries of being ill 'back home'. The ethnographic approach follows the scenes of medical travel within the Indian corporate hospital room, based on observations and interviews among foreign patients, caregivers, and hospital staff in Mumbai, New Delhi, Chennai, and Bangalore. Foreign patients conveyed diverse sentiments about their journey to India ranging from betrayal to gratitude, and their expressions of risk, healthcare costs, and cultural difference help sustain India's popularity as a medical travel destination. However, although the affective dimensions of medical travel promise a remedy for foreign patients, they also reveal the fault lines of market medicine in India.

  3. How spatio-temporal habitat connectivity affects amphibian genetic structure

    USGS Publications Warehouse

    Watts, Alexander G.; Schlichting, P; Billerman, S; Jesmer, B; Micheletti, S; Fortin, M.-J.; Funk, W.C.; Hapeman, P; Muths, Erin L.; Murphy, M.A.

    2015-01-01

    Heterogeneous landscapes and fluctuating environmental conditions can affect species dispersal, population genetics, and genetic structure, yet understanding how biotic and abiotic factors affect population dynamics in a fluctuating environment is critical for species management. We evaluated how spatio-temporal habitat connectivity influences dispersal and genetic structure in a population of boreal chorus frogs (Pseudacris maculata) using a landscape genetics approach. We developed gravity models to assess the contribution of various factors to the observed genetic distance as a measure of functional connectivity. We selected (a) wetland (within-site) and (b) landscape matrix (between-site) characteristics; and (c) wetland connectivity metrics using a unique methodology. Specifically, we developed three networks that quantify wetland connectivity based on: (i) P. maculata dispersal ability, (ii) temporal variation in wetland quality, and (iii) contribution of wetland stepping-stones to frog dispersal. We examined 18 wetlands in Colorado, and quantified 12 microsatellite loci from 322 individual frogs. We found that genetic connectivity was related to topographic complexity, within- and between-wetland differences in moisture, and wetland functional connectivity as contributed by stepping-stone wetlands. Our results highlight the role that dynamic environmental factors have on dispersal-limited species and illustrate how complex asynchronous interactions contribute to the structure of spatially-explicit metapopulations.

  4. Iron affects the structure of cell membrane molecular models.

    PubMed

    Suwalsky, M; Martínez, F; Cárdenas, H; Grzyb, J; Strzałka, K

    2005-03-01

    The effects of Fe(3+) and Fe(2+) on molecular models of biomembranes were investigated. These consisted of bilayers of dimyristoylphosphatidylcholine (DMPC) and of dimyristoylphosphatidylethanolamine (DMPE), classes of phospholipids located in the outer and inner moieties of cell membranes, respectively. X-ray studies showed that very low concentrations of Fe(3+) affected DMPC organization and 10(-3)M induced a total loss of its multilamellar periodic stacking. Experiments carried out with Fe(2+) on DMPC showed weaker effects than those induced by Fe(3+) ions. Similar experiments were performed on DMPE bilayers. Fe(3+) from 10(-7)M up to 10(-4)M had practically no effect on DMPE structure. However, 10(-3)M Fe(3+) induced a deep perturbation of the multilamellar structure of DMPE. However, 10(-3)M Fe(2+) had no effect on DMPE organization practically. Differential scanning calorimetry measurements also revealed different effects of Fe(3+) and Fe(2+) on the phase transition and other thermal properties of the examined lipids. In conclusion, the results obtained indicate that iron ions interact with phospholipid bilayers perturbing their structures. These findings are consistent with the observation that iron ions change cell membrane fluidity and, therefore, affect its functions. PMID:15752465

  5. How spatio-temporal habitat connectivity affects amphibian genetic structure

    PubMed Central

    Watts, Alexander G.; Schlichting, Peter E.; Billerman, Shawn M.; Jesmer, Brett R.; Micheletti, Steven; Fortin, Marie-Josée; Funk, W. Chris; Hapeman, Paul; Muths, Erin; Murphy, Melanie A.

    2015-01-01

    Heterogeneous landscapes and fluctuating environmental conditions can affect species dispersal, population genetics, and genetic structure, yet understanding how biotic and abiotic factors affect population dynamics in a fluctuating environment is critical for species management. We evaluated how spatio-temporal habitat connectivity influences dispersal and genetic structure in a population of boreal chorus frogs (Pseudacris maculata) using a landscape genetics approach. We developed gravity models to assess the contribution of various factors to the observed genetic distance as a measure of functional connectivity. We selected (a) wetland (within-site) and (b) landscape matrix (between-site) characteristics; and (c) wetland connectivity metrics using a unique methodology. Specifically, we developed three networks that quantify wetland connectivity based on: (i) P. maculata dispersal ability, (ii) temporal variation in wetland quality, and (iii) contribution of wetland stepping-stones to frog dispersal. We examined 18 wetlands in Colorado, and quantified 12 microsatellite loci from 322 individual frogs. We found that genetic connectivity was related to topographic complexity, within- and between-wetland differences in moisture, and wetland functional connectivity as contributed by stepping-stone wetlands. Our results highlight the role that dynamic environmental factors have on dispersal-limited species and illustrate how complex asynchronous interactions contribute to the structure of spatially-explicit metapopulations. PMID:26442094

  6. Numerical Simulations of Floodplain Heterogeneity Effects on Meanders Migration

    NASA Astrophysics Data System (ADS)

    Bogoni, M.; Lanzoni, S.; Putti, M.

    2014-12-01

    Floodplains and sinuous rivers have a close relationship with each other, mutually influencing their evolutions in time and space. The heterogeneity in erosional resistance has a crucial role on meander planform evolution. It depends on external factors, like land use and cover, but also on the composition of the floodplain, which is due to the ancient geological composition and to the processes associated to long-term river migration. In particular, banks erosion and deposition cause a variation of the superficial composition of the soil, therefore the river patterns are influenced by the previous trends. Based on some recent works, the aim of this contribution is to collect numerical information on the relations between meander migration and the heterogeneity of floodplains caused by oxbow lakes. Numerical simulations have been performed to analyze the temporal and spatial behavior of meanders with a range of values of the erosional resistance of the plain. These values are set as a function of some factors: the characteristic grain size of sediment transported by the flow, the deposition age of the sediments, the eventual presence of vegetation on the banks. The statistical analysis of characteristic geometrical quantities of meanders are able to show the dependence of the simulation results on the meander history. In particular we try to answer to the following questions: how do the rivers affect themselves during their spatial and temporal evolution, modifying the distribution of the floodplain erodibility? Do the migration history plays a main role on the meanders migration modeling?

  7. A Geomorphic Analysis of Floodplain Lakes along the Embanked Lower Mississippi River for Managing Hydrologic Connectivity

    NASA Astrophysics Data System (ADS)

    Hudson, Paul; Boot, Dax; Sounny-Slitinne, M. Anwar; Kristensen, Kristiaan

    2015-04-01

    A Geomorphic Analysis of Floodplain Lakes along the Embanked Lower Mississippi River for Managing Hydrologic Connectivity Floodplain lakes are vital to the environmental integrity of lowland rivers. Embankment by levees (dikes) for flood control greatly reduces the size of lowland floodplains and is detrimental to the quality and functioning of floodplain water bodies, presenting a challenge to government agencies charged with environmental management. The embanked floodplain of the Lower Mississippi River is an enormous surface which includes a variety of lake types formed by geomorphic and anthropogenic processes. While much is known about the channel and hydrologic regime, very little is known about the physical structure and functioning of the embanked floodplain of the lower Mississippi. Importantly, management agencies do not have an inventory of the basic characteristics (e.g., type, frequency, location, size, shape) of water bodies within the lower Mississippi embanked floodplain. An analysis of lakes along the Lower Mississippi River embanked floodplain is performed by utilizing the National Hydrographic Dataset (NHD) from the U.S. Geological Survey, a LiDAR digital elevation model (DEM), as well as streamflow data from the USGS. The vector NHD data includes every official mapped water body (blue line polygons) on USGS topographic maps at scales of 1:100,000 and 1:24,000. Collectively, we identify thousands of discreet water bodies within the embanked floodplain. Utilizing planimetric properties the water bodies were classified into the following lake types: cutoffs (neck and chute), sloughs, crevasse (scour), local drainage (topographic), and borrow pits. The data is then statistically analyzed to examine significant differences in the spatial variability in lake types along the entire lower Mississippi embanked floodplain in association with geomorphic divisions and hydrologic regime. The total embanked floodplain area of the LMR is 7,303 km2,. The total

  8. 44 CFR 9.15 - Planning programs affecting land use.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ..., DEPARTMENT OF HOMELAND SECURITY GENERAL FLOODPLAIN MANAGEMENT AND PROTECTION OF WETLANDS § 9.15 Planning programs affecting land use. The Agency shall take floodplain management into account when formulating or... flood hazards and floodplain management and wetlands protection; and (b) Prescribes planning...

  9. 44 CFR 9.15 - Planning programs affecting land use.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ..., DEPARTMENT OF HOMELAND SECURITY GENERAL FLOODPLAIN MANAGEMENT AND PROTECTION OF WETLANDS § 9.15 Planning programs affecting land use. The Agency shall take floodplain management into account when formulating or... flood hazards and floodplain management and wetlands protection; and (b) Prescribes planning...

  10. 44 CFR 9.15 - Planning programs affecting land use.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ..., DEPARTMENT OF HOMELAND SECURITY GENERAL FLOODPLAIN MANAGEMENT AND PROTECTION OF WETLANDS § 9.15 Planning programs affecting land use. The Agency shall take floodplain management into account when formulating or... flood hazards and floodplain management and wetlands protection; and (b) Prescribes planning...

  11. 44 CFR 9.15 - Planning programs affecting land use.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ..., DEPARTMENT OF HOMELAND SECURITY GENERAL FLOODPLAIN MANAGEMENT AND PROTECTION OF WETLANDS § 9.15 Planning programs affecting land use. The Agency shall take floodplain management into account when formulating or... flood hazards and floodplain management and wetlands protection; and (b) Prescribes planning...

  12. 44 CFR 9.15 - Planning programs affecting land use.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ..., DEPARTMENT OF HOMELAND SECURITY GENERAL FLOODPLAIN MANAGEMENT AND PROTECTION OF WETLANDS § 9.15 Planning programs affecting land use. The Agency shall take floodplain management into account when formulating or... flood hazards and floodplain management and wetlands protection; and (b) Prescribes planning...

  13. Changes in lowland floodplain sedimentation processes: pre-disturbance to post-rehabilitation, Cosumnes River, CA

    NASA Astrophysics Data System (ADS)

    Florsheim, Joan L.; Mount, Jeffrey F.

    2003-12-01

    generally upward coarsening sequence that reflects depositional processes and land use changes that continue to affect the lowland Cosumnes River floodplain.

  14. Does Question Structure Affect Exam Performance in the Geosciences?

    NASA Astrophysics Data System (ADS)

    Day, E. A.; D'Arcy, M. K.; Craig, L.; Streule, M. J.; Passmore, E.; Irving, J. C. E.

    2015-12-01

    The jump to university level exams can be challenging for some students, often resulting in poor marks, which may be detrimental to their confidence and ultimately affect their overall degree class. Previous studies have found that question structure can have a strong impact on the performance of students in college level exams (see Gibson et al., 2015, for a discussion of its impact on physics undergraduates). Here, we investigate the effect of question structure on the exam results of geology and geophysics undergraduate students. Specifically, we analyse the performance of students in questions that have a 'scaffolded' framework and compare them to their performance in open-ended questions and coursework. We also investigate if observed differences in exam performance are correlated with the educational background and gender of students, amongst other factors. It is important for all students to be able to access their degree courses, no matter what their backgrounds may be. Broadening participation in the geosciences relies on removing systematic barriers to achievement. Therefore we recommend that exams are either structured with scaffolding in questions at lower levels, or students are explicitly prepared for this transition. We also recommend that longitudinal studies of exam performance are conducted within individual departments, and this work outlines one approach to analysing performance data.

  15. Floodplain architecture of an actively meandering river (the Ploučnice River, the Czech Republic) as revealed by the distribution of pollution and electrical resistivity tomography

    NASA Astrophysics Data System (ADS)

    Matys Grygar, T.; Elznicová, J.; Tůmová, Š.; Faměra, M.; Balogh, M.; Kiss, T.

    2016-02-01

    The aim of this study was to describe the floodplain architecture of the Ploučnice River, a naturally meandering river in the Czech Republic, using manual drill coring, the element analysis of sediments, and electrical resistivity tomography (ERT). The Ploučnice River has received diffuse pollution since the early twentieth century (mainly Pb) followed by a prominent, temporally well-defined pollution pulse from uranium mining in the 1970s and 1980s (mainly U and 226Ra). The pollution created a chemostratigraphic (temporal) framework for overbank fines. We used geographical information systems (GIS) to describe the channel's dynamics and visualise fluvial landforms. We sampled and analysed the finest floodplain sediments in the top 1 to 2 m of the floodplain fill (silty and sandy deposits), and we used ERT to visualise bodies of coarser and deeper strata at depths down to ~ 3 m. Several limits of ERT imaging have been found by a comparison of the resistivity domains with lithological descriptions of the cores: several decimetre-thick strata were not revealed (they are below the spatial resolution of that method), and humidity affected the results that were obtained in the topmost strata. The space for deposition of fluvial sediments in the Ploučnice River is being created by (1) natural lateral shifts in the channel (up to 0.5 m/year); (2) meander loop development and cutoffs at the timescale of decades to centuries and spatial scale of up to ~ 1/4 of the floodplain width; and (3) more substantial reorganisation of the channel structure by avulsions, probably at the timescale of centuries. These processes continuously create space for the deposition of overbank fines on the top of former point bars and in swales and abandoned channels. As a consequence of the speed of the channel shifts, at least 80% of the fine-grained top of the floodplain fill (overbank fines) was reworked over approximately three centuries.

  16. Hyperlipidemia affects multiscale structure and strength of murine femur.

    PubMed

    Ascenzi, Maria-Grazia; Lutz, Andre; Du, Xia; Klimecky, Laureen; Kawas, Neal; Hourany, Talia; Jahng, Joelle; Chin, Jesse; Tintut, Yin; Nackenhors, Udo; Keyak, Joyce

    2014-07-18

    To improve bone strength prediction beyond limitations of assessment founded solely on the bone mineral component, we investigated the effect of hyperlipidemia, present in more than 40% of osteoporotic patients, on multiscale structure of murine bone. Our overarching purpose is to estimate bone strength accurately, to facilitate mitigating fracture morbidity and mortality in patients. Because (i) orientation of collagen type I affects, independently of degree of mineralization, cortical bone׳s micro-structural strength; and, (ii) hyperlipidemia affects collagen orientation and μCT volumetric tissue mineral density (vTMD) in murine cortical bone, we have constructed the first multiscale finite element (mFE), mouse-specific femoral model to study the effect of collagen orientation and vTMD on strength in Ldlr(-/-), a mouse model of hyperlipidemia, and its control wild type, on either high fat diet or normal diet. Each µCT scan-based mFE model included either element-specific elastic orthotropic properties calculated from collagen orientation and vTMD (collagen-density model) by experimentally validated formulation, or usual element-specific elastic isotropic material properties dependent on vTMD-only (density-only model). We found that collagen orientation, assessed by circularly polarized light and confocal microscopies, and vTMD, differed among groups and that microindentation results strongly correlate with elastic modulus of collagen-density models (r(2)=0.85, p=10(-5)). Collagen-density models yielded (1) larger strains, and therefore lower strength, in simulations of 3-point bending and physiological loading; and (2) higher correlation between mFE-predicted strength and 3-point bending experimental strength, than density-only models. This novel method supports ongoing translational research to achieve the as yet elusive goal of accurate bone strength prediction.

  17. Spatial patterns of aquatic habitat richness in the Upper Mississippi River floodplain, USA

    USGS Publications Warehouse

    De Jager, Nathan R.; Rohweder, Jason J.

    2012-01-01

    Interactions among hydrology and geomorphology create shifting mosaics of aquatic habitat patches in large river floodplains (e.g., main and side channels, floodplain lakes, and shallow backwater areas) and the connectivity among these habitat patches underpins high levels of biotic diversity and productivity. However, the diversity and connectivity among the habitats of most floodplain rivers have been negatively impacted by hydrologic and structural modifications that support commercial navigation and control flooding. We therefore tested the hypothesis that the rate of increase in patch richness (# of types) with increasing scale reflects anthropogenic modifications to habitat diversity and connectivity in a large floodplain river, the Upper Mississippi River (UMR). To do this, we calculated the number of aquatic habitat patch types within neighborhoods surrounding each of the ≈19 million 5-m aquatic pixels of the UMR for multiple neighborhood sizes (1–100 ha). For all of the 87 river-reach focal areas we examined, changes in habitat richness (R) with increasing neighborhood length (L, # pixels) were characterized by a fractal-like power function R = Lz (R2 > 0.92 (P z) measures the rate of increase in habitat richness with neighborhood size and is related to a fractal dimension. Variation in z reflected fundamental changes to spatial patterns of aquatic habitat richness in this river system. With only a few exceptions, z exceeded the river-wide average of 0.18 in focal areas where side channels, contiguous floodplain lakes, and contiguous shallow-water areas exceeded 5%, 5%, and 10% of the floodplain respectively. In contrast, z was always less than 0.18 for focal areas where impounded water exceeded 40% of floodplain area. Our results suggest that rehabilitation efforts that target areas with <5% of the floodplain in side channels, <5% in floodplain lakes, and/or <10% in shallow-water areas could improve habitat diversity across multiple scales in the UMR.

  18. 40 CFR 258.11 - Floodplains.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) SOLID WASTES CRITERIA FOR MUNICIPAL SOLID WASTE LANDFILLS Location Restrictions § 258.11 Floodplains. (a) Owners or operators of new MSWLF... capacity of the floodplain, or result in washout of solid waste so as to pose a hazard to human health...

  19. Floodplain management: Land acquisition versus preservation of historic buildings in Cambridge, Ontario, Canada

    NASA Astrophysics Data System (ADS)

    Bennett, Wendy J.; Mitchell, Bruce

    1983-07-01

    Non-structural adjustments in floodplain management are often avoided because they are seen to infringe on personal rights, adversely affect property values and restrict local tax bases. Land acquisition programs in urban areas encounter a further problem when they lead to demolition of buildings and other structures considered to have historical or architectural value. An experience in Cambridge, Ontario demonstrates that the potential conflict between flood damage reduction and historical preservation objectives can be exacerbated as a result of uncoordinated planning efforts, inflexibility in interpreting mandates, unclear roles for participating agencies, and lack of cooperation Many of these dilemmas can be resolved through consultation and discussion early in the planning process as well as through a willingness to be flexible and to search for a compromise

  20. Response of fishes to floodplain connectivity during and following a 500-year flood event in the unimpounded upper Mississippi River

    USGS Publications Warehouse

    Barko, V.A.; Herzog, D.P.; O'Connell, M. T.

    2006-01-01

    We examined data collected on fish assemblage structure among three differing floodplain types (broad, moderate, and narrow) during the 1993 flood in the unimpounded reach of the upper Mississippi River. This 500 year flood event provided a unique opportunity to investigate fish-floodplain function because the main river channel is otherwise typically disjunct from approximately 82% of its floodplain by an extensive levee system. Fishes were sampled during three separate periods, and 42 species of adult and young-of-the-year (YOY) fishes were captured. Analysis of similarity (ANOSIM) revealed a significant and distinguishable difference between both adult and YOY assemblage structure among the three floodplain types. Analysis of variance revealed that Secchi transparency, turbidity, water velocity, and dissolved oxygen were significantly different among the floodplain types. However, only depth of gear deployment and Secchi transparency were significantly correlated with adult assemblage structure. None of these variables were significantly correlated with YOY assemblage structure. The numerically abundant families (adult and YOY catches combined) on the floodplain included Centrarchidae, Ictularidae, and Cyprinidae. Both native and non-native fishes were captured on the floodplain, and several of the numerically abundant species that were captured on the floodplain peaked in catch-per-unit-effort 1-3 years after the 1993 flood event. This suggests that some species may have used flooded terrestrial habitat for spawning, feeding, or both. The findings from our study provide much needed insight into fish-floodplain function in a temperate, channelized river system and suggest that lateral connectivity of the main river channel to less degraded reaches of its floodplain should become a management priority not only to maintain faunal biodiversity but also potentially reduce the impacts of non-native species in large river systems.

  1. Impact of a changed inundation regime caused by climate change and floodplain rehabilitation on population viability of earthworms in a lower River Rhine floodplain.

    PubMed

    Thonon, Ivo; Klok, Chris

    2007-01-01

    River floodplains are dynamic and fertile ecosystems where soil invertebrates such as earthworms can reach high population densities. Earthworms are an important food source for a wide range of organisms including species under conservation such as badgers. Flooding, however, reduces earthworm numbers. Populations recover from cocoons that survive floods. If the period between two floods is too short such that cocoons cannot develop into reproductive adults, populations cannot sustain themselves. Both climate change and floodplain rehabilitation change the flooding frequency affecting earthworm populations. The present paper estimates the influence of climate change and floodplain rehabilitation on the viability of earthworm populations in a Dutch floodplain; the Afferdensche and Deestsche Waarden along the River Waal. This floodplain will be part of major river rehabilitation plans of the Dutch government. In those plans, the floodplain will experience the construction of a secondary channel and the removal of part of its minor embankment. To estimate the impact of these plans and climate change, we used a dataset of daily discharges for 1900-2003 for the River Rhine at the Dutch-German border. We perturbed this dataset to obtain two new datasets under climate change scenarios for 2050 and 2100. From the original and two projected datasets we derived the frequency distributions for the annual periods without inundations for the studied floodplain. We subsequently compared the duration of these inundation-free (dry) periods with the maturation age distribution for L. rubellus as derived from a Dynamic Energy Budget model. This comparison yielded in which parts of our study area and under which climate conditions the populations would still be viable, be able to adapt or become extinct. The results show that climate change has almost no adverse effect on earthworm viability. This is because climate change reduces the flooding frequency during the earthworms growing

  2. Impact of a changed inundation regime caused by climate change and floodplain rehabilitation on population viability of earthworms in a lower River Rhine floodplain.

    PubMed

    Thonon, Ivo; Klok, Chris

    2007-01-01

    River floodplains are dynamic and fertile ecosystems where soil invertebrates such as earthworms can reach high population densities. Earthworms are an important food source for a wide range of organisms including species under conservation such as badgers. Flooding, however, reduces earthworm numbers. Populations recover from cocoons that survive floods. If the period between two floods is too short such that cocoons cannot develop into reproductive adults, populations cannot sustain themselves. Both climate change and floodplain rehabilitation change the flooding frequency affecting earthworm populations. The present paper estimates the influence of climate change and floodplain rehabilitation on the viability of earthworm populations in a Dutch floodplain; the Afferdensche and Deestsche Waarden along the River Waal. This floodplain will be part of major river rehabilitation plans of the Dutch government. In those plans, the floodplain will experience the construction of a secondary channel and the removal of part of its minor embankment. To estimate the impact of these plans and climate change, we used a dataset of daily discharges for 1900-2003 for the River Rhine at the Dutch-German border. We perturbed this dataset to obtain two new datasets under climate change scenarios for 2050 and 2100. From the original and two projected datasets we derived the frequency distributions for the annual periods without inundations for the studied floodplain. We subsequently compared the duration of these inundation-free (dry) periods with the maturation age distribution for L. rubellus as derived from a Dynamic Energy Budget model. This comparison yielded in which parts of our study area and under which climate conditions the populations would still be viable, be able to adapt or become extinct. The results show that climate change has almost no adverse effect on earthworm viability. This is because climate change reduces the flooding frequency during the earthworms growing

  3. Free floodplains of hazwaste facilities

    SciTech Connect

    Wagner, T.P. )

    1994-03-01

    Only when the waters from last year's flooding along the Mississippi River fully recede will the extent of the damage be known. However, property losses are only the most obvious effects; floods also pose less visible threats by spreading contaminated water and sediment over wide areas. Factories, oil-tank farms, bulk-chemical storage facilities and sewage treatment plants historically have been located along water-ways and within floodplains. Such facilities are built to withstand some flooding; however, a major flood can destroy barriers, rupture storage tanks, and wash out material from hazardous and solid waste landfills, and surface impoundments. Water infiltration can lead to increased leachate production, contaminating groundwater and adjacent surface water. The long-term effects from hazardous materials and waste entering floodwaters during the 1993 flood are significant and difficult to mitigate. Regulations and policies should be evaluated, and practical changes instituted to reduce long-term effects from contaminated floodwaters. Such changes include prohibiting hazardous waste management units in floodplains.

  4. Characterising the Geomorphology of Forested Floodplains Using High Resolution Terrestrial Laser Scanning

    NASA Astrophysics Data System (ADS)

    Sear, D. A.; Brasington, J.; Darby, S. E.

    2007-12-01

    Forested floodplain environments represent the undisturbed land cover of most temperate and tropical river systems, but they are under threat from human resource management (Hughes et al., 2005, FLOBAR II Project report). A scientific understanding of forest floodplain processes therefore has relevance to ecosystem conservation and restoration, and the interpretation of pre-historic river and floodplain evolution. Empirical research has highlighted how overbank flows are relatively shallow and strongly modified by floodplain topography and the presence of vegetation and organic debris on the woodland floor [Jeffries et al., 2003, Geomorphology, 51, 61-80; Millington and Sear, 2007, Earth. Surf. Proc. Landforms, 32, doi: 10.1002/esp.1552]. In such instances flow blockage and diversions are common, and there is the possibility of frequent switches from sub-critical to locally super-critical flow. Such conditions also favour turbulence generation, both by wakes and by shear. Consequently, the floodplain terrain (where we take 'terrain' to include the underlying topography, root structures, and organic debris) plays a key role in modulating the processes of erosion and sedimentation that underpin the physical habitat diversity and hydraulic characteristics of complex wooded floodplain surfaces. However, despite the importance of these issues, as yet there are no formal, quantitative, descriptions of the highly complex and spatially diverse micro- and meso-topography that appears to be characteristic of forested floodplain surfaces. To address this gap, we have undertaken detailed surveys on a small floodplain reach within the Highland Water Research Catchment (HWRC: see http://www.geog.soton.ac.uk/research/nfrc/default.asp), which is a UK national reference site for lowland floodplain forest streams. This involved the deployment of a Leica ScanStation terrestrial laser-scanner from 14 setups and ranges of less than 30 m to acquire an extremely high resolution, accurate

  5. The Future Of European Floodplain Wetlands Under A Changing Climate

    NASA Astrophysics Data System (ADS)

    Schneider, Christof; Flörke, Martina; Geerling, Gertjan; Duel, Harm; Grygoruk, Mateusz; Okruszko, Tomasz

    2010-05-01

    large geographical differences in directions and causes. First results of our analysis indicate that in snow affected catchments (e.g. in Eastern Europe), duration and volume of inundation are expected to decrease in the 2050s and inundation may appear earlier in the year. Higher temperatures are reducing the proportion of precipitation falling as snow as well as the duration of snow cover. Hence, our results show considerably reduced snowmelt induced flood peaks. As a consequence, habitat for fish, vertebrates, water birds and floodplain specific vegetation will be reduced causing a loss in biodiversity, floodplain productivity and fish production. In warmer regions, inundation strongly depends on the simulated precipitation patterns rather than temperature. To take into account the uncertainty of climate modelling, two SRES emission scenarios from three different global climate models are applied. This allows identifying regions with contradictory results (e.g. in France) for future floodplain inundation. Junk, W.J., Bayley, P.B. & Sparks, R.E. 1989 The flood pulse concept in river-floodplain systems. Canadian Special Publication of Fisheries and Aquatic Sciences, 110-127.

  6. A comparison of sediment deposition in two adjacent floodplains of the River Adour in southwest France.

    PubMed

    Brunet, R-C; Brian Astin, K

    2008-09-01

    Two floodplains within the catchment of the River Adour (SW France) have been examined in order to analyse spatio-temporal variations in discharge and suspended matter flux. Both floodplain zones were found to be excellent sites for the interception of suspended sediment. The narrow riparian vegetative strips (RVS) within each zone were found to retain 92-98% of the sediment trapped within the floodplain during each of three separate flood events. The precise level of sediment deposited within the floodplain was found to be dependent on micro-topographical features and the nature of the vegetation: the wooded areas within the RVS being particularly effective at trapping sediment. Mean masses of sediment collected in the flood plains ranged from 75 kg m(-2) in the RVS to 0.02 kg m(-2) in the areas of the floodplain inundated by back-up flows. Using data on discharge and sediment fluxes within the catchment gathered over a period of 25 years it is possible to discern how hydroclimatic fluctuations have affected the watershed with periods of sediment retention within the floodplain zones alternating with periods of sediment export. Anthropogenic activity, involving river management, including the cutting of meanders, the construction of dykes for flood prevention and the use of water for agricultural purposes, has also had a major impact during this period, particularly in the downstream areas of the catchment.

  7. Vegetative reproduction capacities of floodplain willows--cutting response to competition and biomass loss.

    PubMed

    Radtke, A; Mosner, E; Leyer, I

    2012-03-01

    While several studies on regeneration in Salicaceae have focused on seedling recruitment, little is known about factors controlling their vegetative reproduction. In two greenhouse experiments, we studied the response of floodplain willows (Salix fragilis, S. viminalis, S. triandra) to competition with Poa trivialis, and to shoot and root removal when planted as vegetative cuttings. In the first experiment, growth performance variables were analysed in relation to full competition, shoot competition, root competition and control, taking into account two different water levels. After 9 weeks, shoots were removed and the resprouting capacity of the bare cuttings was recorded. In the second experiment, the cutting performance of the three floodplain and an additional two fen willow species (S. cinerea, S. aurita) was compared when grown in three different soil compositions and with two different water levels. After 9 weeks, shoot and root biomass was removed and the bare cuttings were replanted to test their ability to resprout. Cutting performance and secondary resprouting were negatively affected by full and shoot competition while root competition had no or weak effects. The floodplain species performed better than the fen species in all soil types and water levels. Secondary resprouting capacity was also higher in the floodplain species, which showed an additional strong positive response to the previous waterlogging treatment. The results contribute to understanding of the vegetative regeneration ecology of floodplain willows, and suggest that the use of vegetative plantings in restoration plantings could be an effective strategy for recovering floodplain forests.

  8. Sediment dynamics within the intertidal floodplain of the lower Amazon River

    NASA Astrophysics Data System (ADS)

    Fricke, A. T.; Nittrouer, C. A.; Ogston, A. S.; Nowacki, D. J.; Asp, N. E.; Souza Filho, P. W.

    2014-12-01

    Tidal influence extends ~800 kilometers upstream of the Amazon River mouth, producing semidiurnal oscillations in water elevation and slowing or reversing the flow of the world's largest river. This tidally influenced reach, known as the tidal river, is flanked by an expansive intertidal floodplain, and includes confluences with two large tributaries, the Xingu and Tapajós. The relative magnitude of the seasonal and tidal signals changes along the length of the tidal river, yielding diverse floodplain environments that span a range of seasonal and tidal influence. Near the upstream limit of tides, natural levees isolate the river from the floodplain during low to moderate flows, while in the lower tidal river, natural levees are absent and river-floodplain exchange is dominated by the tides rather than seasonal variation in river stage. This difference between fluvial and tidal systems strongly affects the nature of sediment exchange between the channel and floodplain, including frequency, duration, and depth of inundation. Here we present data on the impact of this fluvial-tidal continuum on sedimentary processes in the floodplain and resultant depositional signatures. Changes in levee prominence, grain size, and sediment accumulation combine to produce the distinct morphologies of floodplain lakes, intertidal backswamps, and intertidal flats. In addition to sediment accumulation on the periodically exposed floodplain, Amazon River sediment accumulates within the drowned tributary confluences of the Xingu and Tapajós Rivers. Here seasonal and tidal changes in water temperature, discharge, and suspended-sediment concentration drive barotropic and baroclinic flows that transport Amazon River sediment into tributary basins. These findings help to constrain the fate of sediment within the ungauged Amazon tidal river, and will help in understanding the response of the lower Amazon River to changes in accommodation space associated with rising sea level, and changes

  9. 10 CFR 1022.13 - Floodplain or wetland assessment.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 10 Energy 4 2011-01-01 2011-01-01 false Floodplain or wetland assessment. 1022.13 Section 1022.13 Energy DEPARTMENT OF ENERGY (GENERAL PROVISIONS) COMPLIANCE WITH FLOODPLAIN AND WETLAND ENVIRONMENTAL REVIEW REQUIREMENTS Procedures for Floodplain and Wetland Reviews § 1022.13 Floodplain or...

  10. 10 CFR 1022.13 - Floodplain or wetland assessment.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 10 Energy 4 2010-01-01 2010-01-01 false Floodplain or wetland assessment. 1022.13 Section 1022.13 Energy DEPARTMENT OF ENERGY (GENERAL PROVISIONS) COMPLIANCE WITH FLOODPLAIN AND WETLAND ENVIRONMENTAL REVIEW REQUIREMENTS Procedures for Floodplain and Wetland Reviews § 1022.13 Floodplain or...

  11. 24 CFR 55.21 - Notification of floodplain hazard.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 24 CFR part 58 of the hazards of the floodplain location before the execution of documents completing... 24 Housing and Urban Development 1 2010-04-01 2010-04-01 false Notification of floodplain hazard... Urban Development FLOODPLAIN MANAGEMENT Procedures for Making Determinations on Floodplain...

  12. 24 CFR 55.21 - Notification of floodplain hazard.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 24 CFR part 58 of the hazards of the floodplain location before the execution of documents completing... 24 Housing and Urban Development 1 2011-04-01 2011-04-01 false Notification of floodplain hazard... Urban Development FLOODPLAIN MANAGEMENT Procedures for Making Determinations on Floodplain...

  13. 24 CFR 55.21 - Notification of floodplain hazard.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 24 CFR part 58 of the hazards of the floodplain location before the execution of documents completing... 24 Housing and Urban Development 1 2013-04-01 2013-04-01 false Notification of floodplain hazard... Urban Development FLOODPLAIN MANAGEMENT Procedures for Making Determinations on Floodplain...

  14. 10 CFR 1022.13 - Floodplain or wetland assessment.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 10 Energy 4 2012-01-01 2012-01-01 false Floodplain or wetland assessment. 1022.13 Section 1022.13 Energy DEPARTMENT OF ENERGY (GENERAL PROVISIONS) COMPLIANCE WITH FLOODPLAIN AND WETLAND ENVIRONMENTAL REVIEW REQUIREMENTS Procedures for Floodplain and Wetland Reviews § 1022.13 Floodplain or...

  15. 10 CFR 1022.13 - Floodplain or wetland assessment.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 10 Energy 4 2014-01-01 2014-01-01 false Floodplain or wetland assessment. 1022.13 Section 1022.13 Energy DEPARTMENT OF ENERGY (GENERAL PROVISIONS) COMPLIANCE WITH FLOODPLAIN AND WETLAND ENVIRONMENTAL REVIEW REQUIREMENTS Procedures for Floodplain and Wetland Reviews § 1022.13 Floodplain or...

  16. 24 CFR 55.21 - Notification of floodplain hazard.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 24 CFR part 58 of the hazards of the floodplain location before the execution of documents completing... 24 Housing and Urban Development 1 2012-04-01 2012-04-01 false Notification of floodplain hazard... Urban Development FLOODPLAIN MANAGEMENT Procedures for Making Determinations on Floodplain...

  17. 10 CFR 1022.13 - Floodplain or wetland assessment.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 10 Energy 4 2013-01-01 2013-01-01 false Floodplain or wetland assessment. 1022.13 Section 1022.13 Energy DEPARTMENT OF ENERGY (GENERAL PROVISIONS) COMPLIANCE WITH FLOODPLAIN AND WETLAND ENVIRONMENTAL REVIEW REQUIREMENTS Procedures for Floodplain and Wetland Reviews § 1022.13 Floodplain or...

  18. Himalayan sediment fluxes and the floodplain transfer function

    NASA Astrophysics Data System (ADS)

    Lupker, Maarten; Lavé, Jérôme; France-Lanord, Christian; Blard, Pierre Henri

    2013-04-01

    Erosion produces sediments and thereby redistributes mass at the Earth surface. A better understanding of these erosion processes can be gained by studying the products of erosion, i.e. the nature, magnitude and variability of sediment fluxes. On continents, rivers are the main conveyer belts that transport these sediments from source to sink. Owing to the integrative nature of river networks, a downstream river reach can be used to infer erosion processes that occur in upstream catchments. However on large spatial scales, sediment transport processes may affect the sedimentary signal so that the quantification of upstream erosion may not be straightforward. This is especially the case for continental scale basins: sediment sources are separated from sedimentary basins by large alluvial floodplains, where sediments are transported over hundreds to thousands of kilometers. The floodplain transfer function needs to be understood whenever modern river sediments or sedimentary archives are used to reconstruct present and past erosion processes. In this contribution we discuss the magnitude of sediment fluxes from the Himalayan system using sediment gauging and cosmogenic nuclide data and address to what extent sediment transport may bias these estimates. The central part of the Himalayan range is drained by two major rivers, the Ganga and Brahmaputra that convey the products of Himalayan erosion over an extensive floodplain and ultimately to the Indian Ocean. This transfer may bias erosion rates derived from gauged sediment fluxes as part of the sediment flux is trapped in the subsiding foreland basin. This storage term remains however limited and can be quantified using a geochemical budget approach [1]. Floodplain transfer may also affect cosmogenic nuclide derived sediment budgets as sediments may accumulate nuclides during transport which will increase the overall nuclide concentration and hence lead to under-estimate denudation rates. By comparing cosmogenic

  19. Nitrate-transformations during simulated drought on a restored floodplain

    NASA Astrophysics Data System (ADS)

    Hoagland, B.; Russo, T. A.; Schmidt, C. M.; Tran, D.

    2015-12-01

    Water resources in the California Central Valley face challenges due to recurring drought, aging levee systems, and nitrate contamination. As decisions are made to restore floodplain connectivity, soil microbial metabolic pathways such as denitrification, anaerobic ammonium oxidation (anammox), and dissimilatory nitrate reduction to ammonium (DNRA) transform nitrate under saturated soil conditions and may each affect downstream water quality. However, few studies have quantified the contribution of all three pathways to nitrate retention in freshwater systems, and specifically in restored floodplains. Additionally, no former studies quantify the rates of these microbial nitrate transformations during floods after prolonged periods of drought. To test how flood duration impacts nitrogen cycling we added 15N-enriched tracer to soil mesocosms to measure denitrification, anammox, and DNRA transformation rates. In July 2015, we extracted seven soil mesocosms from the floodplain and riverbed of the Lower Cosumnes River in the San Joaquin Basin of California. Cosumnes River water enriched with 15N-NO3- tracer was pumped into each mesocosm at a constant rate simulating flood durations of 20 h, 30 h, and 96 h. Samples were collected from the surface water, soil pore water, drain water, and sediment for measurements of NO3-, NO2-, NH4+, gas isotopes, and DNA extraction. This study aims to demonstrate the relevance of anammox and DNRA to total nitrate retention and characterize the hydrologic conditions most favorable to each pathway.

  20. Ecological validity of river-floodplain system assessment by planktonic crustacean survey (Branchiata: Branchiopoda).

    PubMed

    Illyová, Marta; Matečný, Igor

    2014-07-01

    Studies of the Slovakian Danube have indicated profound changes in the structures of several invertebrate assemblages in the section of the river bypassed by the Gabčíkovo hydroelectric project in 1992 and in adjacent floodplain water bodies. The present study investigates the relationship between hydrological connectivity and species diversity in the old main channel and adjacent left-bank water bodies, using resident cladocerans as indicators of the ecological integrity of the river-floodplain system. The work aimed to quantify cladoceran habitat preferences using habitat values (HV) and indication weights (IW) calculated from data accumulated during long-term monitoring of planktonic communities of the Danube floodplain (1,840.5-1,804 rkm) and supplemented with data from the literature. Although not listed as an indicator group in the European Union Water Framework Directive, cladocerans are shown to be highly apposite in the ecological assessment of river-floodplain systems. Of 71 recorded cladoceran species, 19 taxa showed a preference for eupotamal habitats, 24 species preferred eupotamal B/parapotamal waters, and 28 cladocerans were found to prefer the plesiopotamal/paleopotamal habitat type. Identified habitat types follow a gradient of hydrological connectivity with the main river channel, ranging from the eupotamal to more or less isolated floodplain water bodies. A secondary aim was to use the calculated values to assess the ecological integrity of the river-floodplain system. The key element of this procedure is the calculation of the Floodplain Index (FI) (Chovanec et al. Large Rivers, 15(1-4), 169-185 2005) from the summation of the habitat values and indication weights of all species present at the sampling sites. Calculated index values indicate the extent of disruption to lateral connectivity in the floodplain area.

  1. High methane emission from Siberian river floodplains

    NASA Astrophysics Data System (ADS)

    Mi, Yanjiao; van Huissteden, Ko; Dolman, Han

    2013-04-01

    Methane contributes significantly to global warming. Methane emission is essentially the net result of a balance between CH4 production by methanogenic bacteria in anaerobic soil zones, and CH4 oxidation by methanotrophic bacteria in aerated soil zones and plants. Arctic and sub-arctic permafrost holds a large amount of climate vulnerable carbon. In particular river floodplains are carbon-rich soils. River floodplains in this area are periodically or permanently submerged. The occurrence of flooding decreases soil oxygen availability, providing an ideal anaerobic environment for methane generation. Here we compare the chamber measurements of the methane flux from tundra and floodplain of the Kytalyk site in Northeast Siberia. Model experiments on this site have also been carried out in order to better explain spatial and temporal variations in methane emissions from northern permafrost. This serves as a basis for further model development including modeling of the flooding regime on the floodplain.

  2. Selecting reconnaissance strategies for floodplain surveys

    NASA Technical Reports Server (NTRS)

    Sollers, S. C.; Rango, A.; Henninger, D. L.

    1977-01-01

    Multispectral aircraft and satellite data over the West Branch of the Susquehanna River were analyzed to evaluate potential contributions of remote sensing to flood-plain surveys. Multispectral digital classifications of land cover features indicative of floodplain areas were used by interpreters to locate various floodprone area boundaries. The digital approach permitted LANDSAT results to be displayed at 1:24,000 scale and aircraft results at even larger scales. Results indicate that remote sensing techniques can delineate floodprone areas more easily in agricultural and limited development areas as opposed to areas covered by a heavy forest canopy. At this time it appears that the remote sensing data would be best used as a form of preliminary planning information or as an internal check on previous or ongoing floodplain studies. In addition, the remote sensing techniques can assist in effectively monitoring floodplain activities after a community enters into the National Flood Insurance Program.

  3. The fate of carbon in floodplain sediments: A biogeochemical approach

    NASA Astrophysics Data System (ADS)

    Alderson, Danielle; Evans, Martin; Rothwell, James; Boult, Stephen; Rhodes, Edward

    2015-04-01

    Inland waters including fluvial systems and their associated sediments have been predominantly overlooked as part of global carbon budgets until recently. In the UK, peatlands are dynamically eroding, with the eventual result being 'off-site' greenhouse gas emissions, which must be incorporated into carbon budgets for management strategies. Evans et al. (2013) concluded fluvial systems are active cyclers of carbon, with 50-90% of particulate organic carbon (POC) exported from peatlands eventually emitted as CO2. Floodplains, although commonly regarded as zones of carbon storage, have been identified as potential hotspots of carbon cycling in the fluvial system with a key process being decomposition of POC. Decomposition is known to involve mass loss with selective transformation of labile compounds such as polysaccharides, and preferential preservation of more resistant compounds (refractory aromatics or aliphatics). Several decomposition proxies including FTIR band intensities, hydrogen indices and C/N ratios, correlated with molecular structure determinations using pyrolysis GC-MS, have been used successfully in peat cores (Biester et al., 2013), to disentangle changes due to decomposition and those that are related to vegetation variation. The aim of this research is to determine whether similar techniques can be applied to arguably more complex systems such as floodplains, to examine stratigraphic records of carbon cycling. Initial results from sediment cores taken within a floodplain environment downstream of the Bleaklow Plateau in the Peak District, UK will be presented. An initial OSL date of 640±90 years BP together with assessment of the valley morphology using high resolution LiDAR DEM's indicate potential interaction of post glacial landslide features with the onset of substantial peat erosion, conditioning the landscape to interrupt the transport of carbon down the fluvial network. The floodplain under investigation is a potential hotspot for carbon

  4. Floodplain Hyporheic Response under Dam Release Hydrographs

    NASA Astrophysics Data System (ADS)

    Zhou, T.; Ward, A. S.; O'Connor, B. L.; Endreny, T. A.

    2012-12-01

    Hydropower operations cause altered hydrograph patterns downstream of dams, which regulates the direction and magnitude of floodplain and riverbed hyporheic flux. Periodic adjustments in river stage changes temporal and spatial patterns in hydraulic pressure, initiates propagation of lateral and vertical hyporheic flux, and affects the riparian ecological system by changing the hyporheic penetration distance, hyporheic flux rate, and thermal conditions in river banks. While this issue has been largely neglected by watershed scientists and managers, there is the potential to use hyporheic metrics in setting dam release rules and restoring downstream river reaches. In order to evaluate the hyporheic feedbacks of various dam release patterns, this study applied a computational fluid dynamics (CFD) model to simulate the interaction of open water hydrographs on porous media lateral hyporheic exchange for the Green River, Utah, downstream of Flaming Gorge Dam. The CFD initially represented the river as a straight channel with a thick porous media extending from the channel banks and bottom. The dam release hydrographs changed the patterns of hyporheic flux at the river banks, the penetration distance of the hyporheic flux, the subsurface thermal patterns, and the residence time of water in the subsurface. The results suggest the undulating river stage downstream of dam releases can initiate patterns of hyporheic exchange similar to those induced by restoration of river bed morphology.

  5. Hydrodynamic Modeling of Flood Dynamics and Restoration Potential of Lower Missouri River Floodplains

    NASA Astrophysics Data System (ADS)

    Lindner, G. A.

    2012-12-01

    Lower Missouri River floodplains have the potential to provide multiple ecosystem services including agricultural production, floodwater storage, nutrient processing, and provision of habitats. In this research, a 2-dimensional hydrodynamic model of a representative looped floodplain bottom of approximately 20 km is utilized to explore how floodplain inundation contributes to ecosystem benefits and costs. High resolution 2-dimensional hydrodynamic modeling provides insights into the way velocities, flood stages, residence times, and transported constituents (sediment, nutrients, and fish larvae, for example) are affected by levee geometry, floodplain vegetation patterns, and flood magnitude and duration. The utility of 2-dimensional numerical hydraulic models to represent the channel and floodplain are demonstrated at a scale relevant to understanding processes that control channel/floodplain dynamics. The sensitivity of model response to alternative land use scenarios, including levee setbacks and variable overbank roughness, is quantified using hydraulic parameters such as velocity, water level, conveyance, and residence time. The 2-dimensional models are calibrated to existing 1-dimensional modeling solutions and field measurements of water surface from 1993 and 2007 for the 2-year, 5-year, and 10-year recurrence intervals. Calibration runs with current levee configurations are matched to approximately ±0.1 meters. Simulations of alternative land use scenarios demonstrate the tradeoffs between ecological restoration and flood risk reductions. Levee setbacks with low hydraulic roughness associated with traditional row crop agriculture on the floodplains have the greatest potential for flood stage reductions, while native plant communities with higher roughness can negate the effects of the setbacks by increasing water levels due to enhanced frictional resistance. Residence times, which are presumed to be related to ecosystem services, demonstrate increasingly

  6. Cosmogenic nuclide budgeting of floodplain sediment transfer

    NASA Astrophysics Data System (ADS)

    Wittmann, H.; von Blanckenburg, F.

    2009-08-01

    Cosmogenic nuclides produced in quartz may either decay or accumulate while sediment is moved through a river basin. A change in nuclide concentration resulting from storage in a floodplain is potentially important in large drainage basins in which sediment is prone to repeated burial and remobilization as a river migrates through its floodplain. We have modeled depth- and time-dependent cosmogenic nuclide concentration changes for 10Be, 26Al, and 14C during sediment storage and mixing in various active floodplain settings ranging from confined, shallow rivers with small floodplains to foreland-basin scale floodplains traversed by deep rivers. Floodplain storage time, estimated from channel migration rates, ranges from 0.4 kyr for the Beni River basin (Bolivia) to 7 kyr for the Amazon River basin, while floodplain storage depth, estimated from channel depth, ranges from 1 to 25 m. For all modeled active floodplain settings, the long-lived nuclides 10Be and 26Al show neither significant increase in nuclide concentration from irradiation nor decrease from decay. We predict a hypothetical response time after which changes in 10Be or 26Al concentrations become analytically resolvable. This interval ranges from 0.07 to 2 Myr and exceeds in all cases the typical residence time of sediment in a floodplain. Due to the much shorter half life of 14C, nuclide concentrations modeled for the in situ-produced variety of this nuclide are, however, sensitive to floodplain storage on residence times of < 20 kyr. The cosmogenic nuclide composition of old deposits in currently inactive floodplains that have been isolated for periods of millions of years from the river that once deposited them is predicted to either increase or decrease in 10Be and 26Al concentration, depending on the depositional depth. These conditions can be evaluated using the 26Al/ 10Be ratio that readily discloses the depth and duration of storage. We illustrate these models with examples from the Amazon basin

  7. Sucrose prevents protein fibrillation through compaction of the tertiary structure but hardly affects the secondary structure.

    PubMed

    Estrela, Nídia; Franquelim, Henri G; Lopes, Carlos; Tavares, Evandro; Macedo, Joana A; Christiansen, Gunna; Otzen, Daniel E; Melo, Eduardo P

    2015-11-01

    Amyloid fibers, implicated in a wide range of diseases, are formed when proteins misfold and stick together in long rope-like structures. As a natural mechanism, osmolytes can be used to modulate protein aggregation pathways with no interference with other cellular functions. The osmolyte sucrose delays fibrillation of the ribosomal protein S6 leading to softer and less shaped-defined fibrils. The molecular mechanism used by sucrose to delay S6 fibrillation was studied based on the two-state unfolding kinetics of the secondary and tertiary structures. It was concluded that the delay in S6 fibrillation results from stabilization and compaction of the slightly expanded tertiary native structure formed under fibrillation conditions. Interestingly, this compaction extends to almost all S6 tertiary structure but hardly affects its secondary structure. The part of the S6 tertiary structure that suffered more compaction by sucrose is known to be the first part to unfold, indicating that the native S6 has entered the unfolding pathway under fibrillation conditions.

  8. How Knowledge Management Is Affected by Organizational Structure

    ERIC Educational Resources Information Center

    Mahmoudsalehi, Mehdi; Moradkhannejad, Roya; Safari, Khalil

    2012-01-01

    Purpose: Identifying the impact of organizational structure on knowledge management (KM) is the aim of this study, as well as recognizing the importance of each variable indicator in creating, sharing and utility of knowledge. Design/methodology/approach: For understanding relationships between the main variables (organizational structure-KM), the…

  9. Preliminary paleohydrological interpretation of an Amazon floodplain system based on seismic stratigraphy: Varzea do Lago Grande do Curuai, Pará, Brazil.

    NASA Astrophysics Data System (ADS)

    Amorim, M. A.; Moreira-Turcq, P.; Turcq, B.

    2009-04-01

    The aquatic lacustrine ecosystems are depositional environments that register in yours sediments the process that occurs on the own site and in the all drainage basin. The Amazonas River and its tributaries are followed along your upward and downward course by several floodplains that cover a large area of environs 300.000 km2. These sites are dynamic and complexes systems. Floodplains affect the erosion the transport and the sedimentation flux in the system and it has a special importance for carbon cycle due yours high productivity. In the floodplains systems the sediment deposition occurs in a different scale of time period. In these work, we study the "Varzea Grande do Curuai" which size varies from 1340km2 during the dry season, to 3600 km2 during the wet season, according to the level of the river. This floodplain is located on the southern margin of the Amazonas River, close to the city of Óbidos, Pará-Brazil, in the Lower Amazonas. The floodplain contains several white water lakes such as Grande, Poção, Santa Ninha and Salé Lakes, and black water lakes such as the Curumucuri and Açaí Lakes. These lakes are connected to each other and to the Amazonas River by small channels, some of which are permanently connected to the river and others not, depending on the variations of the water level. The purpose of this work is to reconstruct past sedimentary processes using seismic stratigraphy profiles realized all along the floodplain lakes and sediment cores collected at strategic sites. The sedimentary patterns observed in the seismic profiles are horizontal layers, highly reflective unpenetrated levels and paleochannels that could have been formed during the Holocene. The larger quantity of paleochannels along the lakes has been observed in the Grande and Salé lakes. The paleochannels in the Grande Lake would indicate a migration of actual depositional ridge that separates the floodplain from the river. In the Salé Lake, the paleochannels indicate that

  10. A faster and economical approach to floodplain mapping using the SSURGO soil database

    NASA Astrophysics Data System (ADS)

    Sangwan, N.; Merwade, V.

    2014-12-01

    Floods are the most damaging of all natural disasters, adversely affecting millions of lives and causing financial losses worth billions of dollars every year across the globe. Flood inundation maps play a key role in the assessment and mitigation of potential flood hazards. However, there are several communities in the United States where flood risk maps are not available due to the lack of the resources needed to create such maps through the conventional modeling approach. The objective of this study is to develop and examine an economical alternative approach to floodplain mapping using widely available SSURGO soil data in the United States. By using the state of Indiana as a test case, floodplain maps are developed for the entire state by identifying the flood-prone soil map units based on their attributes recorded in the SSURGO database. For validation, the flood extents obtained from the soil data are compared with the extents predicted by other floodplain maps, including the Federal Emergency Management Agency (FEMA) issued Flood Insurance Rate Maps (FIRM), flood extents observed during past floods, and other flood maps derived using Digital Elevation Models (DEMs). In general, SSURGO based floodplain maps are found to be largely in agreement with flood inundation maps created by FEMA. Comparison between the FEMA maps and the SSURGO derived floodplain maps show an overlap ranging from 65 to 90 percent. Similar results are also found when the SSURGO derived floodplain maps are compared with FEMA maps for recent flood events in other states including Minnesota, Washington and Wisconsin. Although not in perfect conformance with reference flood maps, the SSURGO soil data approach offers an economical and faster alternative to floodplain mapping in areas where detailed flood modeling and mapping has not been conducted.

  11. Impacts of Hurricane Katrina on floodplain forests of the Pearl River: Chapter 6A in Science and the storms-the USGS response to the hurricanes of 2005

    USGS Publications Warehouse

    Faulkner, Stephen; Barrow, Wylie; Couvillion, Brady R.; Conner, William; Randall, Lori; Baldwin, Michael

    2007-01-01

    Floodplain forests are an important habitat for Neotropical migratory birds. Hurricane Katrina passed through the Pearl River flood plain shortly after making landfall. Field measurements on historical plots and remotely sensed data were used to assess the impact of Hurricane Katrina on the structure of floodplain forests of the Pearl River.

  12. Large scale distribution of bacterial communities in the upper Paraná River floodplain

    PubMed Central

    Chiaramonte, Josiane Barros; Roberto, Maria do Carmo; Pagioro, Thomaz Aurélio

    2014-01-01

    A bacterial community has a central role in nutrient cycle in aquatic habitats. Therefore, it is important to analyze how this community is distributed throughout different locations. Thirty-six different sites in the upper Paraná River floodplain were surveyed to determine the influence of environmental variable in bacterial community composition. The sites are classified as rivers, channels, and floodplain lakes connected or unconnected to the main river channel. The bacterial community structure was analyzed by fluorescent in situ hybridization (FISH) technique, based on frequency of the main domains Bacteria and Archaea, and subdivisions of the phylum Proteobacteria (Alpha-proteobacteria, Beta-proteobacteria, Gamma-proteobacteria) and the Cytophaga-Flavobacterium cluster. It has been demonstrated that the bacterial community differed in density and frequency of the studied groups. And these differences responded to distinct characteristics of the three main rivers of the floodplain as well as to the classification of the environments found in this floodplain. We conclude that dissimilarities in the bacterial community structure are related to environmental heterogeneity, and the limnological variables that most predicted bacterial communities in the upper Paraná River floodplain was total and ammoniacal nitrogen, orthophosphate and chlorophyll-a. PMID:25763022

  13. Adaptation services of floodplains and wetlands under transformational climate change.

    PubMed

    Colloff, Matthew; Lavorel, Sandra; Wise, Russell M; Dunlop, Michael; Overton, Ian C; Williams, Kristen J

    2016-06-01

    Adaptation services are the ecosystem processes and services that benefit people by increasing their ability to adapt to change. Benefits may accrue from existing but newly used services where ecosystems persist or from novel services supplied following ecosystem transformation. Ecosystem properties that enable persistence or transformation are important adaptation services because they support future options. The adaptation services approach can be applied to decisions on trade-offs between currently valued services and benefits from maintaining future options. For example, ecosystem functions and services of floodplains depend on river flows. In those regions of the world where climate change projections are for hotter, drier conditions, floods will be less frequent and floodplains will either persist, though with modified structure and function, or transform to terrestrial (flood-independent) ecosystems. Many currently valued ecosystem services will reduce in supply or become unavailable, but new options are provided by adaptation services. We present a case study from the Murray-Darling Basin, Australia, for operationalizing the adaptation services concept for floodplains and wetlands. We found large changes in flow and flood regimes are likely under a scenario of +1.6°C by 2030, even with additional water restored to rivers under the proposed Murray-Darling Basin Plan. We predict major changes to floodplain ecosystems, including contraction of riparian forests and woodlands and expansion of terrestrial, drought-tolerant vegetation communities. Examples of adaptation services under this scenario include substitution of irrigated agriculture with dryland cropping and floodplain grazing; mitigation of damage from rarer, extreme floods; and increased tourism, recreational, and cultural values derived from fewer, smaller wetlands that can be maintained with environmental flows. Management for adaptation services will require decisions on where intervention can

  14. Adaptation services of floodplains and wetlands under transformational climate change.

    PubMed

    Colloff, Matthew; Lavorel, Sandra; Wise, Russell M; Dunlop, Michael; Overton, Ian C; Williams, Kristen J

    2016-06-01

    Adaptation services are the ecosystem processes and services that benefit people by increasing their ability to adapt to change. Benefits may accrue from existing but newly used services where ecosystems persist or from novel services supplied following ecosystem transformation. Ecosystem properties that enable persistence or transformation are important adaptation services because they support future options. The adaptation services approach can be applied to decisions on trade-offs between currently valued services and benefits from maintaining future options. For example, ecosystem functions and services of floodplains depend on river flows. In those regions of the world where climate change projections are for hotter, drier conditions, floods will be less frequent and floodplains will either persist, though with modified structure and function, or transform to terrestrial (flood-independent) ecosystems. Many currently valued ecosystem services will reduce in supply or become unavailable, but new options are provided by adaptation services. We present a case study from the Murray-Darling Basin, Australia, for operationalizing the adaptation services concept for floodplains and wetlands. We found large changes in flow and flood regimes are likely under a scenario of +1.6°C by 2030, even with additional water restored to rivers under the proposed Murray-Darling Basin Plan. We predict major changes to floodplain ecosystems, including contraction of riparian forests and woodlands and expansion of terrestrial, drought-tolerant vegetation communities. Examples of adaptation services under this scenario include substitution of irrigated agriculture with dryland cropping and floodplain grazing; mitigation of damage from rarer, extreme floods; and increased tourism, recreational, and cultural values derived from fewer, smaller wetlands that can be maintained with environmental flows. Management for adaptation services will require decisions on where intervention can

  15. Seasonal and spatial aspects of the eco-distribution of methanotrophic bacteria in floodplain soils

    NASA Astrophysics Data System (ADS)

    Bodelier, P. L. E.; Meima-Franke, M.; Kamst, M.; Bodrossy, L.; Stralis-Pavese, N.; Hefting, M. M.; Laanbroek, R.

    2009-04-01

    METHECO is the acronym of a consortium of research groups funded by the European Science foundation (ESF) within the EuroDIVERSITY program. The consortium investigates the role of microbial diversity in the dynamics and stability of global methane consumption. The consortium covers various habitats (i.e. Landfills, rice paddies, alpine meadows, littoral wetlands, forests, arctic wetlands, peat soils and river floodplains) and assesses the effects of natural environmental perturbation on the function structure relationship of methane-consuming microbial communities. Consortium members follow the same experimental and methodological scheme using DNA and RNA based techniques (i.e. pmoA-based cloning, DGGE, micro arrays, Real Time PCR, stable isotope probing). This paper presents the results obtained in a river floodplain along the river Rhine in the Netherlands, a habitat anticipated to be subjected to major changes in flooding regime due to climate change. Experiments were carried out to assess methanotrophic diversity, methane oxidation kinetics and spatial variability of function and structure of methane-oxidizing communities. Flooding events affected methane consumption negatively on short term. However, the long -term consequences of the flooding regime where the establishment of a distinct maximum methane consumption activity exactly in the part of the floodplain intermediate between permanently and irregularly flooded, where moisture and organic matter content were optimal for methane cycling. The methanotrophic community composition as analysed by pmoA micro array mirrored the result of the activity measurements, demonstrating that the communities differed clearly according to the flooding gradient. Diversity as assessed by micro array and activity components (initial consumption, Vmax, Vmax/Km) were positively correlated. QPCR analyses showed that main types of methanotrophic bacteria were differentially distributed throughout the flooding gradient. Type I

  16. Hydromorphological control of nutrient cycling in complex river floodplain systems

    NASA Astrophysics Data System (ADS)

    Hein, T.; Bondar-Kunze, E.; Felkl, M.; Habersack, H.; Mair, M.; Pinay, G.; Tritthart, M.; Welti, N.

    2009-04-01

    Riparian zones and floodplains are key components within river ecosystems controlling nutrient cycling by promoting transformation processes and thus, act as biogeochemical hot spots. The intensity of these processes depends on the exchange conditions (the connectivity) with the main channel and the morphological setting of the water bodies. At the landscape scale, three interrelated principles of hydromorphological dynamics can be formulated regarding the cycling and transfer of carbon and nutrients in large rivers ecosystems: a) The mode of carbon and nutrient delivery affects ecosystem functioning; b) Increasing residence time and contact area impact nutrient transformation; c) Floods and droughts are natural events that strongly influence pathways of carbon and nutrient cycling. These three principles of hydromorphological dynamics control the nutrient uptake and retention and are linked over different temporal and spatial scales. All three factors can be strongly affected by natural disturbances or anthropogenic impacts, through a change in either the water regime or the geomorphologic setting of the river valley. Any change in natural water regimes will affect the biogeochemistry of riparian zones and floodplains as well as their ability to cycle and mitigate nutrient fluxes originating from upstream and/or upslope. Especially these areas have been altered by river regulation and land use changes over the last 200 years leading to the deterioration of the functioning of these compartments within the riverine landscape. The resulting deficits have prompted rehabilitation and restoration measures aiming to increase the spatial heterogeneity, the complexity, of these ecosystems. Yet, a more integrated approach is needed considering the present status of nutrient dynamics and the effects of restoration measures at different scales. The present paper analyses the effects of river side-arm restoration on ecosystem functions within the side-arm and highlights

  17. Phosphate Ions Affect the Water Structure at Functionalized Membrane Surfaces.

    PubMed

    Barrett, Aliyah; Imbrogno, Joseph; Belfort, Georges; Petersen, Poul B

    2016-09-01

    Antifouling surfaces improve function, efficiency, and safety in products such as water filtration membranes, marine vehicle coatings, and medical implants by resisting protein and biofilm adhesion. Understanding the role of water structure at these materials in preventing protein adhesion and biofilm formation is critical to designing more effective coatings. Such fouling experiments are typically performed under biological conditions using isotonic aqueous buffers. Previous studies have explored the structure of pure water at a few different antifouling surfaces, but the effect of electrolytes and ionic strength (I) on the water structure at antifouling surfaces is not well studied. Here sum frequency generation (SFG) spectroscopy is used to characterize the interfacial water structure at poly(ether sulfone) (PES) and two surface-modified PES films in contact with 0.01 M phosphate buffer with high and low salt (Ionic strength, I= 0.166 and 0.025 M, respectively). Unmodified PES, commonly used as a filtration membrane, and modified PES with a hydrophobic alkane (C18) and with a poly(ethylene glycol) (PEG) were used. In the low ionic strength phosphate buffer, water was strongly ordered near the surface of the PEG-modified PES film due to exclusion of phosphate ions and the creation of a surface potential resulting from charge separation between phosphate anions and sodium cations. However, in the high ionic strength phosphate buffer, the sodium and potassium chloride (138 and 3 mM, respectively) in the phosphate buffered saline screened this charge and substantially reduced water ordering. A much smaller water ordering and subsequent reduction upon salt addition was observed for the C18-modified PES, and little water structure change was seen for the unmodified PES. The large difference in water structuring with increasing ionic strength between widely used phosphate buffer and phosphate buffered saline at the PEG interface demonstrates the importance of studying

  18. Structural and leakage integrity of tubes affected by circumferential cracking

    SciTech Connect

    Hernalsteen, P.

    1997-02-01

    In this paper the author deals with the notion that circumferential cracks are generally considered unacceptable. He argues for the need to differentiate two facets of such cracks: the issue of the size and growth rate of a crack; and the issue of the structural strength and leakage potential of the tube in the presence of the crack. In this paper the author tries to show that the second point is not a major concern for such cracks. The paper presents data on the structural strength or burst pressure characteristics of steam generator tubes derived from models and data bases of experimental work. He also presents a leak rate model, and compares the performance of circumferential and axial cracks as far as burst strength and leak rate. The final conclusion is that subject to improvement in NDE capabilities (sizing, detection, growth), that Steam Generator Defect Specific Management can be used to allow circumferentially degraded tubes to remain in service.

  19. Stage structure alters how complexity affects stability of ecological networks

    USGS Publications Warehouse

    Rudolf, V.H.W.; Lafferty, Kevin D.

    2011-01-01

    Resolving how complexity affects stability of natural communities is of key importance for predicting the consequences of biodiversity loss. Central to previous stability analysis has been the assumption that the resources of a consumer are substitutable. However, during their development, most species change diets; for instance, adults often use different resources than larvae or juveniles. Here, we show that such ontogenetic niche shifts are common in real ecological networks and that consideration of these shifts can alter which species are predicted to be at risk of extinction. Furthermore, niche shifts reduce and can even reverse the otherwise stabilizing effect of complexity. This pattern arises because species with several specialized life stages appear to be generalists at the species level but act as sequential specialists that are hypersensitive to resource loss. These results suggest that natural communities are more vulnerable to biodiversity loss than indicated by previous analyses.

  20. Does small scale structure significantly affect cosmological dynamics?

    PubMed

    Adamek, Julian; Clarkson, Chris; Durrer, Ruth; Kunz, Martin

    2015-02-01

    The large-scale homogeneity and isotropy of the Universe is generally thought to imply a well-defined background cosmological model. It may not. Smoothing over structure adds in an extra contribution, transferring power from small scales up to large. Second-order perturbation theory implies that the effect is small, but suggests that formally the perturbation series may not converge. The amplitude of the effect is actually determined by the ratio of the Hubble scales at matter-radiation equality and today-which are entirely unrelated. This implies that a universe with significantly lower temperature today could have significant backreaction from more power on small scales, and so provides the ideal testing ground for understanding backreaction. We investigate this using two different N-body numerical simulations-a 3D Newtonian and a 1D simulation which includes all relevant relativistic effects. We show that while perturbation theory predicts an increasing backreaction as more initial small-scale power is added, in fact the virialization of structure saturates the backreaction effect at the same level independently of the equality scale. This implies that backreaction is a small effect independently of initial conditions. Nevertheless, it may still contribute at the percent level to certain cosmological observables and therefore it cannot be neglected in precision cosmology. PMID:25699430

  1. Earthworm ecology affects the population structure of their Verminephrobacter symbionts.

    PubMed

    Viana, Flávia; Jensen, Christopher Erik; Macey, Michael; Schramm, Andreas; Lund, Marie Braad

    2016-05-01

    Earthworms carry species-specific Verminephrobacter symbionts in their nephridia (excretory organs). The symbionts are vertically transmitted via the cocoon, can only colonize the host during early embryonic development, and have co-speciated with their host for about 100 million years. Although several studies have addressed Verminephrobacter diversity between worm species, the intra-species diversity of the symbiont population has never been investigated. In this study, symbiont population structure was examined by using a multi-locus sequence typing (MLST) approach on Verminephrobacter isolated from two contrasting ecological types of earthworm hosts: the high population density, fast reproducing compost worms, Eisenia andrei and Eisenia fetida, and the low-density, slow reproducing Aporrectodea tuberculata, commonly found in garden soils. Three distinct populations were investigated for both types and, according to MLST analysis of 193 Verminephrobacter isolates, the symbiont community in each worm individual was very homogeneous. The more solitary A. tuberculata carried unique symbiont populations in 9 out of 10 host individuals, whereas the symbiont populations in the social compost worms were homogeneous across host individuals from the same population. These data suggested that host ecology shaped the population structure of Verminephrobacter symbionts. The homogeneous symbiont populations in the compost worms led to the hypothesis that Verminephrobacter could be transferred bi-parentally or via leaky horizontal transmission in high-density, frequently mating worm populations. PMID:27040820

  2. Does Small Scale Structure Significantly Affect Cosmological Dynamics?

    NASA Astrophysics Data System (ADS)

    Adamek, Julian; Clarkson, Chris; Durrer, Ruth; Kunz, Martin

    2015-02-01

    The large-scale homogeneity and isotropy of the Universe is generally thought to imply a well-defined background cosmological model. It may not. Smoothing over structure adds in an extra contribution, transferring power from small scales up to large. Second-order perturbation theory implies that the effect is small, but suggests that formally the perturbation series may not converge. The amplitude of the effect is actually determined by the ratio of the Hubble scales at matter-radiation equality and today—which are entirely unrelated. This implies that a universe with significantly lower temperature today could have significant backreaction from more power on small scales, and so provides the ideal testing ground for understanding backreaction. We investigate this using two different N -body numerical simulations—a 3D Newtonian and a 1D simulation which includes all relevant relativistic effects. We show that while perturbation theory predicts an increasing backreaction as more initial small-scale power is added, in fact the virialization of structure saturates the backreaction effect at the same level independently of the equality scale. This implies that backreaction is a small effect independently of initial conditions. Nevertheless, it may still contribute at the percent level to certain cosmological observables and therefore it cannot be neglected in precision cosmology.

  3. Reach scale floodplain inundation dynamics observed using airborne synthetic aperture radar imagery: Data analysis and modelling

    NASA Astrophysics Data System (ADS)

    Bates, Paul D.; Wilson, Matthew D.; Horritt, Matthew S.; Mason, David C.; Holden, Nick; Currie, Anthony

    2006-08-01

    SummaryIn this paper, we use an airborne synthetic aperture radar to map river flood inundation synoptically at fine spatial resolution (1.2 m) along a ˜16 km reach of the River Severn, west-central England. Images were obtained at four times through a large flood event between 8th and 17th November 2000 and processed using a statistical active contour algorithm to yield the flood shoreline at each time. Intersection of these data with a high vertical accuracy survey of floodplain topography obtained from airborne laser altimetry permitted the calculation of dynamic changes in inundated area, total reach storage and rates of reach dewatering. In addition, comparison of the data to gauged flow rates, the measured floodplain topography and map data giving the location of embankments and drainage channels on the floodplain yields new insights into the factors controlling the development of inundation patterns at a variety of scales. Finally, the data were used to assess the performance of a simple two-dimensional flood inundation model, LISFLOOD-FP, and allows us, for the first time, to validate the dynamic performance of the model. This process is shown to give new information into structural weaknesses of the model and suggests possible future developments, including the incorporation of a better description of floodplain hydrological processes in the hydraulic model to represent more accurately the dewatering of the floodplain.

  4. Flood Events, Discharge and Sedimentation On Floodplains

    NASA Astrophysics Data System (ADS)

    Boelscher, J.; Ergenzinger, P.

    The activation of retention areas and the restoration of floodplains have great importance for flood protection and the ecological function of river landscapes. Complex interactions take place between flow velocity, sediment transport, morphology and vegetation within floodplains. This investigation, which is embedded in the framework of the EU Research Project Riparian Forest Management, focuses on these interactions and will give more detailed information about the impact of vegetation on flow field, discharge and sediment transport. Under the aspects of flood retention and river restoration the improved knowledge of these parameters is expected to assist in generating measures for the optimisation of riparian forest management. Hence the objective of this investigation is the description and analysis of : a.) duration and level of inundation b.) spatio-temporal variation of flow velocity and its intensity within the floodplain c.) roughness in the form of substrate, vegetation, morphology and its spatio- temporal variation d.) impact of morphology and vegetation on flow velocity and discharge within the floodplain d.) morphology, vegetation, substrate, sedimentation and erosion before and after subset flood events. The selected area of investigation is located at the upper Rhine, near Freiburg. The test sites within the inv estigated floodplain differ in the type of vegetation, morphology, substrate, aspect and height. These parameters were investigated before and after a longer period of floods. The spatio-temporal variations of flow velocity in the stream and on the floodplain were recorded using Acoustic Doppler Current Profilers. Simultaneously data were collected about the suspended load above the ground and below the water surface. Using a digital video camera, a first attempt was made to monitor the deformation of trees during a single flood event.

  5. Floodplain sedimentation in the Upper Mississippi Valley: Natural versus human accelerated

    NASA Astrophysics Data System (ADS)

    Knox, James C.

    2006-09-01

    Understanding the time scales and pathways for response and recovery of rivers and floodplains to episodic changes in erosion and sedimentation has been a long standing issue in fluvial geomorphology. Floodplains are an important component of watershed systems because they affect downstream storage and delivery of overbank flood waters, and they also serve as sources and temporary sinks for sediments and toxic substances delivered by river systems. Here, 14C and 137Cs isotopic dating methods are used along with ages of culturally related phenomena associated with mining and agriculture to determine rates of sedimentation and morphologic change for a reach of the upper Mississippi River and adjacent tributaries in southwestern Wisconsin and northwestern Illinois. The most important environmental change that influenced fluvial activity in this region during last 10,000 years involved the conversion of a late Holocene mosaic of prairie and forest to a landscape dominated by cropland and pastureland associated with Euro-American settlement. Results presented herein for the Upper Mississippi Valley (UMV) show that the shift from pre-agriculture, natural land cover to landscape dominance by agricultural land use of the last 175-200 years typically increased rates and magnitudes of floodplain sedimentation by at least an order of magnitude. Accelerated overbank flooding led to increased bank heights on tributary streams and, in turn, contributed to more frequent deep flows of high energy. These high energy flows subsequently promoted bank erosion and lateral channel migration, and the formation of a historical meander belt whose alluvial surface constitutes a new historical floodplain inset against the earlier historical floodplain. The new historical floodplain serves as a "flume-like" channel that provides efficient downstream transport of water and sediment associated with moderate and large magnitude floods. Floodplains on lower tributaries, however, continue to

  6. Do terrestrial invertebrates experience floodplains as landscape mosaics? Immediate and longer-term effects of flooding on ant assemblages in a floodplain forest.

    PubMed

    Ballinger, Andrea; Lake, P S; Nally, Ralph Mac

    2007-05-01

    Considering the floodplain landscape as a mosaic of habitat patches at different successional stages is useful for understanding (1) the processes associated with individual floods and (2) the legacy of flood history. Here, we investigate the applicability of the mosaic model to opportunistic ant species inhabiting the floodplain. Ground-active ant assemblages in river red gum (Eucalyptus camaldulensis) floodplain forest in south-eastern Australia were sampled before and for two years after a major flood in 2000-2001 at 24 sites with different inundation histories. Despite the mobility and opportunistic life history traits of floodplain ants, flood history appeared to impose a persistent mosaic structure on ant assemblages. Increasing duration of inundation of the forest floor was associated with decreasing species richness. beta-diversity was low, with the ant species at the most inundation-prone sites being a subset of those at drier sites. Less extensive flooding occurred in 2002-2003, enabling the consistency of short-term responses to inundation to be assessed. Flooding acts as a resetting mechanism, creating a characteristic ant assemblage. After floodwaters receded, there was little evidence of convergence in the structure of ant assemblages through time between sites flooded for different durations. The persistence of dissimilarities in ant assemblages suggests that succession towards terrestrialization was either not occurring or that it was operating at a rate that was too slow to be detected.

  7. Dehydration affects brain structure and function in healthy adolescents.

    PubMed

    Kempton, Matthew J; Ettinger, Ulrich; Foster, Russell; Williams, Steven C R; Calvert, Gemma A; Hampshire, Adam; Zelaya, Fernando O; O'Gorman, Ruth L; McMorris, Terry; Owen, Adrian M; Smith, Marcus S

    2011-01-01

    It was recently observed that dehydration causes shrinkage of brain tissue and an associated increase in ventricular volume. Negative effects of dehydration on cognitive performance have been shown in some but not all studies, and it has also been reported that an increased perceived effort may be required following dehydration. However, the effects of dehydration on brain function are unknown. We investigated this question using functional magnetic resonance imaging (fMRI) in 10 healthy adolescents (mean age = 16.8, five females). Each subject completed a thermal exercise protocol and nonthermal exercise control condition in a cross-over repeated measures design. Subjects lost more weight via perspiration in the thermal exercise versus the control condition (P < 0.0001), and lateral ventricle enlargement correlated with the reduction in body mass (r = 0.77, P = 0.01). Dehydration following the thermal exercise protocol led to a significantly stronger increase in fronto-parietal blood-oxygen-level-dependent (BOLD) response during an executive function task (Tower of London) than the control condition, whereas cerebral perfusion during rest was not affected. The increase in BOLD response after dehydration was not paralleled by a change in cognitive performance, suggesting an inefficient use of brain metabolic activity following dehydration. This pattern indicates that participants exerted a higher level of neuronal activity in order to achieve the same performance level. Given the limited availability of brain metabolic resources, these findings suggest that prolonged states of reduced water intake may adversely impact executive functions such as planning and visuo-spatial processing.

  8. Dehydration affects brain structure and function in healthy adolescents.

    PubMed

    Kempton, Matthew J; Ettinger, Ulrich; Foster, Russell; Williams, Steven C R; Calvert, Gemma A; Hampshire, Adam; Zelaya, Fernando O; O'Gorman, Ruth L; McMorris, Terry; Owen, Adrian M; Smith, Marcus S

    2011-01-01

    It was recently observed that dehydration causes shrinkage of brain tissue and an associated increase in ventricular volume. Negative effects of dehydration on cognitive performance have been shown in some but not all studies, and it has also been reported that an increased perceived effort may be required following dehydration. However, the effects of dehydration on brain function are unknown. We investigated this question using functional magnetic resonance imaging (fMRI) in 10 healthy adolescents (mean age = 16.8, five females). Each subject completed a thermal exercise protocol and nonthermal exercise control condition in a cross-over repeated measures design. Subjects lost more weight via perspiration in the thermal exercise versus the control condition (P < 0.0001), and lateral ventricle enlargement correlated with the reduction in body mass (r = 0.77, P = 0.01). Dehydration following the thermal exercise protocol led to a significantly stronger increase in fronto-parietal blood-oxygen-level-dependent (BOLD) response during an executive function task (Tower of London) than the control condition, whereas cerebral perfusion during rest was not affected. The increase in BOLD response after dehydration was not paralleled by a change in cognitive performance, suggesting an inefficient use of brain metabolic activity following dehydration. This pattern indicates that participants exerted a higher level of neuronal activity in order to achieve the same performance level. Given the limited availability of brain metabolic resources, these findings suggest that prolonged states of reduced water intake may adversely impact executive functions such as planning and visuo-spatial processing. PMID:20336685

  9. Depth as an organizer of fish assemblages in floodplain lakes

    USGS Publications Warehouse

    Miranda, L.E.

    2011-01-01

    Depth reduction is a natural process in floodplain lakes, but in many basins has been accelerated by anthropogenic disturbances. A diverse set of 42 floodplain lakes in the Yazoo River Basin (Mississippi, USA) was examined to test the hypothesis of whether depth reduction was a key determinant of water quality and fish assemblage structure. Single and multiple variable analyses were applied to 10 commonly monitored water variables and 54 fish species. Results showed strong associations between depth and water characteristics, and between depth and fish assemblages. Deep lakes provided less variable environments, clearer water, and a wider range of microhabitats than shallow lakes. The greater environmental stability was reflected by the dominant species in the assemblages, which included a broader representation of large-body species, species less tolerant of extreme water quality, and more predators. Stability in deep lakes was further reflected by reduced among-lake variability in taxa representation. Fish assemblages in shallow lakes were more variable than deep lakes, and commonly dominated by opportunistic species that have early maturity, extended breeding seasons, small adult size, and short lifespan. Depth is a causal factor that drives many physical and chemical variables that contribute to organizing fish assemblages in floodplain lakes. Thus, correlations between fish and water transparency, temperature, oxygen, trophic state, habitat structure, and other environmental descriptors may ultimately be totally or partly regulated by depth. In basins undergoing rapid anthropogenic modifications, local changes forced by depth reductions may be expected to eliminate species available from the regional pool and could have considerable ecological implications. ?? 2010 Springer Basel AG (outside the USA).

  10. Drought responses of flood-tolerant trees in Amazonian floodplains

    PubMed Central

    Parolin, Pia; Lucas, Christine; Piedade, Maria Teresa F.; Wittmann, Florian

    2010-01-01

    Background Flood-tolerant tree species of the Amazonian floodplain forests are subjected to an annual dry period of variable severity imposed when low river-water levels coincide with minimal precipitation. Although the responses of these species to flooding have been examined extensively, their responses to drought, in terms of phenology, growth and physiology, have been neglected hitherto, although some information is found in publications that focus on flooding. Scope The present review examines the dry phase of the annual flooding cycle. It consolidates existing knowledge regarding responses to drought among adult trees and seedlings of many Amazonian floodplain species. Main Findings Flood-tolerant species display variable physiological responses to dry periods and drought that indicate desiccation avoidance, such as reduced photosynthetic activity and reduced root respiration. However, tolerance and avoidance strategies for drought vary markedly among species. Drought can substantially decrease growth, biomass and photosynthetic activity among seedlings in field and laboratory studies. When compared with the responses to flooding, drought can impose higher seedling mortality and slower growth rates, especially among evergreen species. Results indicate that tolerance and avoidance strategies for drought vary markedly between species. Both seedling recruitment and photosynthetic activity are affected by drought, Conclusions For many species, the effects of drought can be as important as flooding for survival and growth, particularly at the seedling phase of establishment, ultimately influencing species composition. In the context of climate change and predicted decreases in precipitation in the Amazon Basin, the effects of drought on plant physiology and species distribution in tropical floodplain forest ecosystems should not be overlooked. PMID:19880423

  11. Gall structure affects ecological associations of Dryocosmus kuriphilus (Hymenoptera: Cynipidae).

    PubMed

    Cooper, W Rodney; Rieske, Lynne K

    2010-06-01

    Gall wasps (Hymenoptera: Cynipidae) induce structures (galls) on their host plants that house developing wasps and provide them with protection from natural enemies. The Asian chestnut gall wasp, Dryocosmus kuriphilus Yasumatsu, is an invasive pest that is destructive to chestnut (Castanea spp.). An improved understanding of the interactions among D. kuriphilus, its host, and its natural enemies is critical for the development of effective management strategies against this pest. The objective of our study was to evaluate the D. kuriphilus community interactions, and relate these interactions to variations among gall traits. Galls were collected from four locations throughout the eastern United States from May (gall initiation) through August (after gall wasp emergence), and January. Gall characteristics (volume, weight, and schlerenchyma layer thickness), gall inhabitants (D. kuriphilus, parasitoids, and chamber fungi), and other community associates (insect herbivores and lesions thought to be caused by endophytes) were evaluated and correlated using canonical correlation analyses. The primary mortality factors for D. kuriphilus were parasitism, gall chamber-invading fungi, and failure of adult gall wasps to emerge. Larger gall size and thicker schlerenchyma layers surrounding the larval chambers were negatively correlated with parasitoids and chamber fungi, indicating these gall traits are important defenses. External fungal lesions and insect herbivory were positively correlated with the absence of D. kuriphilus within galls. This study provides support for the protective role of cynipid galls for the gall inducer, identifies specific gall traits that influence gall wasp mortality, and improves our knowledge of D. kuriphilus ecology in North America.

  12. Aluminum fluoride affects the structure and functions of cell membranes.

    PubMed

    Suwalsky, M; Norris, B; Villena, F; Cuevas, F; Sotomayor, P; Zatta, P

    2004-06-01

    No useful biological function for aluminum has been found. To the contrary, it might play an important role in several pathologies, which could be related to its interactions with cell membranes. On the other hand, fluoride is a normal component of body fluids, soft tissues, bones and teeth. Its sodium salt is frequently added to drinking water to prevent dental caries. However, large doses cause severe pathological alterations. In view of the toxicity of Al(3+) and F(-) ions, it was thought of interest to explore the damaging effects that AlF(3) might induce in cell membranes. With this aim, it was incubated with human erythrocytes, which were examined by phase contrast and scanning electron microscopy, and molecular models of biomembranes. The latter consisted of large unilamellar vesicles (LUV) of dimyristoylphosphatidylcholine (DMPC) and bilayers of DMPC and dimyristoylphosphatidylethanolamine (DMPE) which were studied by fluorescence spectroscopy and X-ray diffraction, respectively. In order to understand the effects of AlF(3) on ion transport (principally sodium and chloride) we used the isolated toad skin to which electrophysiological measurements were applied. It was found that AlF(3) altered the shape of erythrocytes inducing the formation of echinocytes. This effect was explained by X-ray diffraction which revealed that AlF(3) perturbed the structure of DMPC, class of lipids located in the outer monolayer of the erythrocyte membrane. This result was confirmed by fluorescence spectroscopy on DMPC LUV. The biphasic (stimulatory followed by inhibitory) effects on the isolated skin suggested changes in apical Cl(-) secretion and moderate ATPase inactivation. PMID:15110101

  13. Use of ALS data for digital terrain extraction and roughness parametrization in floodplain areas

    NASA Astrophysics Data System (ADS)

    Idda, B.; Nardinocchi, C.; Marsella, M.

    2009-04-01

    In order to undertake structural and land planning actions aimed at improving risk thresholds and vulnerability associated to floodplain inundation, the evaluation of the area concerning the channel overflowing from his natural embankments it is of essential importance. Floodplain models requires the analysis of historical floodplains extensions, ground's morphological structure and hydraulic measurements. Within this set of information, a more detailed characterization about the hydraulic roughness, which controls the velocity to the hydraulic flow, is a interesting challenge to achieve a 2D spatial distribution into the model. Remote sensing optical and radar sensors techniques can be applied to generate 2D and 3D map products useful to perimeter floodplains extension during the main event and extrapolate river cross-sections. Among these techniques, it is unquestionable the enhancement that the Airborne Laser Scanner (ALS) have brought for its capability to extract high resolution and accurate Digital Terrain Models. In hydraulic applications, a number of studies investigated the use of ALS for DTM generation and approached the quantitative estimations of the hydraulic roughness. The aim of this work is the generation of a digital terrain model and the estimation of hydraulic parameters useful for floodplains models from Airborne Laser Scanner data collected in a test area, which encloses a portion of a drainage basin of the Mela river (Sicily, Italy). From the Airborne Laser Scanner dataset, a high resolution Digital Elevation Model was first created, then after applying filtering and classification processes, a dedicated procedure was implemented to assess automatically a value for the hydraulic roughness coefficient (in Manning's formulation) per each point interested in the floodplain. The obtained results allowed to generate maps of equal roughness, hydraulic level depending, based on the application of empirical formulas for specific-type vegetation at

  14. Trace metal dynamics in floodplain soils of the river Elbe: a review.

    PubMed

    Schulz-Zunkel, Christiane; Krueger, Frank

    2009-01-01

    This paper reviews trace metal dynamics in floodplain soils using the Elbe floodplains in Germany as an example of extraordinary importance because of the pollution level of its sediments and soils. Trace metal dynamics are determined by processes of retention and release, which are influenced by a number of soil properties including pH value, redox potential, organic matter, type and amount of clay minerals, iron-, manganese- and aluminum-oxides. Today floodplains act as important sinks for contaminants but under changing hydraulic and geochemical conditions they may also act as sources for pollutants. In floodplains such changes may be extremes in flooding or dry periods that particularly lead to altered redox potentials and that in turn influence the pH value, the mineralization of organic matter as well as the charge of the pedogenic oxides. Such reactions may affect the bioavailability of trace metals in soils and it can be clearly seen that the bioavailability of metals is an important factor for estimating trace metal remobilization in floodplain soils. However as bioavailability is not a constant factor, there is still a lack of quantification of metal mobilization particularly on the basis of changing geochemical conditions. Moreover, mobile amounts of metals in the soil solution do not indicate to which extent remobilized metals will be transported to water bodies or plants and therefore potentially have toxicological effects. Consequently, floodplain areas still need to be taken into consideration when studying the role and behavior of sediments and soils for transporting pollutants within river systems, particularly concerning the Water Framework Directive.

  15. Trace metal dynamics in floodplain soils of the river Elbe: a review.

    PubMed

    Schulz-Zunkel, Christiane; Krueger, Frank

    2009-01-01

    This paper reviews trace metal dynamics in floodplain soils using the Elbe floodplains in Germany as an example of extraordinary importance because of the pollution level of its sediments and soils. Trace metal dynamics are determined by processes of retention and release, which are influenced by a number of soil properties including pH value, redox potential, organic matter, type and amount of clay minerals, iron-, manganese- and aluminum-oxides. Today floodplains act as important sinks for contaminants but under changing hydraulic and geochemical conditions they may also act as sources for pollutants. In floodplains such changes may be extremes in flooding or dry periods that particularly lead to altered redox potentials and that in turn influence the pH value, the mineralization of organic matter as well as the charge of the pedogenic oxides. Such reactions may affect the bioavailability of trace metals in soils and it can be clearly seen that the bioavailability of metals is an important factor for estimating trace metal remobilization in floodplain soils. However as bioavailability is not a constant factor, there is still a lack of quantification of metal mobilization particularly on the basis of changing geochemical conditions. Moreover, mobile amounts of metals in the soil solution do not indicate to which extent remobilized metals will be transported to water bodies or plants and therefore potentially have toxicological effects. Consequently, floodplain areas still need to be taken into consideration when studying the role and behavior of sediments and soils for transporting pollutants within river systems, particularly concerning the Water Framework Directive. PMID:19465710

  16. Nitrate loss from a restored floodplain on the lower Cosumnes River, California

    NASA Astrophysics Data System (ADS)

    Sheibley, R. W.; Ahearn, D. S.; Santoriello, P.; Dahlgren, R. A.

    2002-12-01

    Floodplain habit was recreated on the lower Cosumnes River by breaching levees that previously protected agricultural lands from seasonal flooding. This study examined the ability of restored floodplains to retain nutrients from the river during flood events. The study looked at the potential for nitrate loss utilizing two techniques: (i) potential denitrification rates of floodplain soils and (ii) nitrate loss from floodplain waters during in situ microcosm experiments. Soils samples were collected from 13 locations within the floodplain and analyzed for denitrification potential. Denitrification potentials ranged from 0.06 to 27.5 nmol N2O cm-3 hr-1 and correlated with the concentrations of total N, organic C, sand and silt in the soils. Furthermore, denitrification potential correlated well with microbial respiration rates suggesting that concentrations of labile carbon strongly affect microbial activity and subsequent denitrification. Microcosm experiments were conducted by inserting polycarbonate tubes approximately 20 cm into the sediment. In addition, a replicate set of columns was studied which excluded the sediment layer to distinguish water column processes from those occurring within the sediments. The overlying water was spiked with nitrate and bromide to observe changing nitrate concentrations over time. Three different levels of nitrate were examined: ambient, +1 ppm nitrate, and +5 ppm nitrate. Results showed that nitrate loss from the water column was rapid and a function of the initial nitrate concentration. Nitrate was completely removed within 68 to 163 hours for the background and +5ppm treatments, respectively. Rates of nitrate disappearance were ~ 2.5 times greater in the sediment/water treatment, with approximately 20-30% of the nitrate being lost from water column alone. Results from this study document the potential role of these floodplain habitats to reduce the amount of nitrate that is transported downstream to sensitive aquatic

  17. Legacy effects of colonial millponds on floodplain sedimentation, bank erosion, and channel morphology, MID-Atlantic, USA

    USGS Publications Warehouse

    Schenk, E.R.; Hupp, C.R.

    2009-01-01

    Many rivers and streams of the Mid-Atlantic Region, United States (U.S.) have been altered by postcolonial floodplain sedimentation (legacy sediment) associated with numerous milldams. Little Conestoga Creek, Pennsylvania, a tributary to the Susquehanna River and the Chesapeake Bay, is one of these streams. Floodplain sedimentation rates, bank erosion rates, and channel morphology were measured annually during 2004-2007 at five sites along a 28-km length of Little Conestoga Creek with nine colonial era milldams (one dam was still in place in 2007). This study was part of a larger cooperative effort to quantify floodplain sedimentation, bank erosion, and channel morphology in a high sediment yielding region of the Chesapeake Bay watershed. Data from the five sites were used to estimate the annual volume and mass of sediment stored on the floodplain and eroded from the banks for 14 segments along the 28-km length of creek. A bank and floodplain reach based sediment budget (sediment budget) was constructed for the 28 km by summing the net volume of sediment deposited and eroded from each segment. Mean floodplain sedimentation rates for Little Conestoga Creek were variable, with erosion at one upstream site (-5 mm/year) to deposition at the other four sites (highest = 11 mm/year) despite over a meter of floodplain aggradation from postcolonial sedimentation. Mean bank erosion rates range between 29 and 163 mm/year among the five sites. Bank height increased 1 m for every 10.6 m of channel width, from upstream to downstream (R2 = 0.79, p < 0.0001) resulting in progressively lowered hydraulic connectivity between the channel and the floodplain. Floodplain sedimentation and bank erosion rates also appear to be affected by the proximity of the segments to one existing milldam, which promotes deposition upstream and scouring downstream. The floodplain and bank along the 28-km reach produced a net mean sediment loss of 5,634 Mg/year for 2004-2007, indicating that bank

  18. The Department of Energy`s floodplain/wetlands review

    SciTech Connect

    Votteler, T.H.

    1992-06-01

    Two Executive Orders (E.O.) issued in 1977, Floodplain Management (E.O. 11988) and Protection of Wetlands (E.O. 11990), require that Federal agencies examine the impacts of proposed actions on floodplains and wetlands. To comply with these Orders, the US Department of Energy (DOE) promulgated 10 CFR 1022, DOE Regulations for Compliance with Floodplain/Wetlands Environmental Review Requirements. DOE`s floodplain/wetlands review consists of two procedures: the floodplain/wetlands determination, and the floodplain/wetlands assessment. The floodplain/wetlands determination ascertains the applicability of DOE`s floodplain management and wetlands protection requirements for a proposed action. If DOE`s requirements apply to a proposed action, DOE shall prepare a floodplain/wetlands assessment. The floodplain/wetlands assessment ascertains an action`s impact, any alternatives, and mitigation, if appropriate. The assessment consists of a project description, an analysis of the potential impacts, and a consideration of alternatives to the proposed action. This paper describes the components of the DOE floodplain/wetlands review process.

  19. Inventory and Comparison of Floodplain Embankment along Large Rivers

    NASA Astrophysics Data System (ADS)

    Hudson, Paul

    2016-04-01

    Flood control is a fundamental human response to flood risk, and floodplain embankment by dike (levee) construction is among the oldest forms of societal impacts to natural systems. Large lowland alluvial valleys are some of Earth's most distinctive environments and represent high levels of geodiversity and biodiversity. Embankment of large lowland alluvial river valleys alters fundamental processes related to floodplain hydrology, sedimentation, and ecology and eventually results in a transformation of the embanked floodplain environment. Since embankment, many large lowland floodplains have been heaviliy modified for floodplain agriculture and include high population densities, increasing flood risk. While there is much discussion about the pros and cons of dike construction and the impact to floodplain environments there is no systematic inventory which documents the magnitude and intensity of floodplain embankment to lowland rivers. In this study we characterize and inventory floodplain embankment along large lowland alluvial valleys. The review includes some of Earth's largest embanked fluvial systems, and primarilly focuses on northern hemisphere rivers in the United States, Europe and Asia. Data sources includes the U.S. National Levee Database, SRTM DEM, recently obtained high resolution satellite imagery, various national topographic map series, and hydrologic data from the published literature. These data are integrated into a GIS framework to facilitate the measurement and characterisation of floodplain embankment. Spatial indices of floodplain embankment are constructed, including the intensity of embankment and how it relates to the natural floodplain and constriction of flooding.

  20. The Department of Energy's floodplain/wetlands review

    SciTech Connect

    Votteler, T.H.

    1992-06-01

    Two Executive Orders (E.O.) issued in 1977, Floodplain Management (E.O. 11988) and Protection of Wetlands (E.O. 11990), require that Federal agencies examine the impacts of proposed actions on floodplains and wetlands. To comply with these Orders, the US Department of Energy (DOE) promulgated 10 CFR 1022, DOE Regulations for Compliance with Floodplain/Wetlands Environmental Review Requirements. DOE's floodplain/wetlands review consists of two procedures: the floodplain/wetlands determination, and the floodplain/wetlands assessment. The floodplain/wetlands determination ascertains the applicability of DOE's floodplain management and wetlands protection requirements for a proposed action. If DOE's requirements apply to a proposed action, DOE shall prepare a floodplain/wetlands assessment. The floodplain/wetlands assessment ascertains an action's impact, any alternatives, and mitigation, if appropriate. The assessment consists of a project description, an analysis of the potential impacts, and a consideration of alternatives to the proposed action. This paper describes the components of the DOE floodplain/wetlands review process.

  1. Mapping Floodplain Stratigraphy at an Archaeological Site in Upstate New York Using Shallow Sub-Surface Geophysics

    NASA Astrophysics Data System (ADS)

    Hasbargen, L. E.; Klink, C.; Johnson, E.; Anthony, D.

    2008-12-01

    across the floodplain collecting 1 meter-spaced profiles. We surveyed endpoints of each profile using global positioning system receivers and a total station electronic distance measurement tool. Thus, we could hang the profiles in a geospatial reference frame, and combine our data with other georeferenced data sets. The profiles extend to roughly 1.3 m depth, at which point the signal was strongly attenuated. A strongly reflective irregular surface, which we interpret as channel and bar structures, can be traced for considerable distance across the floodplain in the subsurface. The buried channels run approximately parallel to the modern channel. They are not obviously related to the shallow flood channels on the modern floodplain. Our results rule out a simple growth of the floodplain via a laterally sweeping channel. The presence of multiple channels and bars implies abrupt shifts of the main channel. Modern channel and floodplain features nearby exhibit similar channel and bar structures with floodplains etched by small flood channels, thus providing a direct analog for understanding the subsurface features at the Pine Lake floodplain.

  2. The role of run-of-river impoundments in CO2 and CH4 emissions from floodplains of the Delaware Piedmont, Christina River Basin Critical Zone Observatory

    NASA Astrophysics Data System (ADS)

    Pearson, A.; Pizzuto, J. E.; Vargas, R.

    2014-12-01

    There is strong interest in understanding how run-of-river impoundments affect streams and their floodplains. Most recent work has focused on the fate of sediment within these dammed systems both past and current, the geomorphic impacts associated with sediment, and issues associated with removing run-of-the-river dams. Here, we assess how run-of-river impoundments alter the floodplain effluxes of carbon dioxide (CO2), and methane (CH4). We sampled two pairs of floodplains on the Red Clay Creek (140 km2) located in the Christina River Basin Critical Zone Observatory. The floodplain pairs were centered on a current and a former location of a run-of-river dam (one floodplain upstream, one downstream of dam location). Each floodplain was subjected to a suite of measurements that included bi-weekly gas flux (CO2, CH4, and H2O), bi-weekly soil moisture and temperature, monthly biomass sampling, C/N ratio sampling from O and A horizons, and cores that constrain the total organic carbon and nitrogen at depth as well as provide a description of the stratigraphy. Preliminary findings show that all floodplains are sources of CH4 (0.18 - 1.12 nmol m-2s-1) and CO2 (0.42 - 3.12 µmol m-2s-1). Despite temporal variability, the upstream floodplains produce more CH4 and CO2 than downstream floodplains. Our results may suggest that run-of-the-river dams enhance release of carbon from floodplains into the atmosphere.

  3. The influence of river regulation and land use on floodplain forest regeneration in the semi-arid upper Colorado River Basin, USA

    USGS Publications Warehouse

    Northcott, K.; Andersen, D.C.; Cooper, D.J.

    2007-01-01

    Flow regulation effects on floodplain forests in the semi-arid western United States are moderately well understood, whereas effects associated with changes in floodplain land use are poorly documented. We mapped land cover patterns from recent aerial photos and applied a classification scheme to mainstem alluvial floodplains in 10 subjectively selected 4th order hydrologic units (subbasins) in the Upper Colorado River Basin (UCRB) in order to document land use patterns (floodplain development) and assess their effects on Fremont cottonwood forest (CF) regeneration. Three of the mainstem rivers were unregulated, five were moderately regulated and two were highly regulated. We classified polygons as Undeveloped (with two categories, including CF) and Developed (with five categories). We ground-truthed 501 randomly selected polygons (4-28% of the floodplain area in each subbasin) to verify classification accuracy and to search for cottonwood regeneration, defined as stands established since regulation began or 1950, whichever is most recent. From 40% to 95% of the floodplain area remained undeveloped, but only 19-70% of the floodplain area was classified as forest. Regeneration occupied a mean of 5% (range 1-17%) of the floodplain. The likelihood of the presence of regeneration in a polygon was reduced 65% by development and independently in a complex manner by flow regulation. Our analyses indicate that floodplain forests may be in jeopardy on both regulated and unregulated rivers and that information on historical forest extent is needed to better understand their current status in the UCRB. Conservation efforts need to be coordinated at a regional level and address the potentially adverse affects of both flow regulation and floodplain development.

  4. Floodplain Organic Carbon Storage in the Central Yukon River Basin

    NASA Astrophysics Data System (ADS)

    Lininger, K.; Wohl, E.

    2014-12-01

    Floodplain storage of organic carbon is an important aspect of the global carbon cycle that is not well understood or quantified. Although it is understood that rivers transport organic carbon to the ocean, little is known about the quantity of stored carbon in boreal floodplains and the influence of fluvial processes on this storage. We present results on total organic carbon (TOC) content within the floodplains of two rivers, the Dall River and Preacher Creek, in the central Yukon River Basin in the Yukon Flats National Wildlife Refuge of Alaska. The results indicate that organic carbon storage is influenced by fluvial disturbance and grain size. The Dall River, which contains a large amount of floodplain carbon, is meandering and incised, with well-developed floodplain soils, a greater percentage of relatively old floodplain surfaces and a slower floodplain turnover time, and finer grain sizes. Preacher Creek stores less TOC, transports coarser grain sizes, and has higher rates of avulsion and floodplain turnover time. Within the floodplain of a particular river, large spatial heterogeneity in TOC content also exists as a function of depositional environment and age and vegetation community of the site. In addition, saturated regions of the floodplains, such as abandoned channels and oxbow lakes, contain more TOC compared to drier floodplain environments. Frozen alluvial soils likely contain carbon that could be released into the environment with melting permafrost, and thus quantifying the organic carbon content in the active layer of floodplain soils could provide insight into the characteristics of the permafrost beneath. The hydrology in these regions is changing due to permafrost melt, and floodplain areas usually saturated could be dried out, causing breakdown and outgassing of carbon stored in previously saturated soils. Ongoing work will result in a first-order estimate of active-layer floodplain carbon storage for the central Yukon River Basin.

  5. Struggle in the flood: tree responses to flooding stress in four tropical floodplain systems

    PubMed Central

    Parolin, Pia; Wittmann, Florian

    2010-01-01

    Background and aims In the context of the 200th anniversary of Charles Darwin's birth in 1809, this study discusses the variation in structure and adaptation associated with survival and reproductive success in the face of environmental stresses in the trees of tropical floodplains. Scope We provide a comparative review on the responses to flooding stress in the trees of freshwater wetlands in tropical environments. The four large wetlands we evaluate are: (i) Central Amazonian floodplains in South America, (ii) the Okavango Delta in Africa, (iii) the Mekong floodplains of Asia and (iv) the floodplains of Northern Australia. They each have a predictable ‘flood pulse’. Although flooding height varies between the ecosystems, the annual pulse is a major driving force influencing all living organisms and a source of stress for which specialized adaptations for survival are required. Main points The need for trees to survive an annual flood pulse has given rise to a large variety of adaptations. However, phenological responses to the flood are similar in the four ecosystems. Deciduous and evergreen species respond with leaf shedding, although sap flow remains active for most of the year. Growth depends on adequate carbohydrate supply. Physiological adaptations (anaerobic metabolism, starch accumulation) are also required. Conclusions Data concerning the ecophysiology and adaptations of trees in floodplain forests worldwide are extremely scarce. For successful floodplain conservation, more information is needed, ideally through a globally co-ordinated study using reproducible comparative methods. In the light of climatic change, with increasing drought, decreased groundwater availability and flooding periodicities, this knowledge is needed ever more urgently to facilitate fast and appropriate management responses to large-scale environmental change. PMID:22476061

  6. Transportation infrastructure, river confinement, and impacts on floodplain and channel habitat, Yakima and Chehalis rivers, Washington, U.S.A.

    NASA Astrophysics Data System (ADS)

    Blanton, Paul; Marcus, W. Andrew

    2013-05-01

    Although floodplain roads and railroads are recognized as confining features with potentially large environmental impacts, few studies have explored the linkages between these structures and the natural disturbance regime that creates and maintains channel and riparian habitat. This study compares paired floodplain reaches with or without transportation infrastructure confining the riparian zone along the Yakima and Chehalis rivers in Washington State. Channel and floodplain habitat were degraded in the artificially confined reaches. Confined channels were narrower, simpler in planform, and relatively devoid of depositional surfaces such as bars and islands. Floodplains adjacent to confined channels exhibited degraded riparian forest and less refugium habitat such as side channels, ponds, and alcoves important for endangered salmonids and other biota. The results support hypotheses about how human modification of the floodplain landscape disrupts the flow regime and connectivity along riparian corridors. Neither simple buffer zones nor metrics such as valley width index adequately capture the disturbance-based landscape processes that drive riparian and channel habitat integrity. Future studies and indices of valley confinement, a critical driver of fluvial geomorphic processes, need to pay closer attention to artificial confinement of the channel, the riparian zone, and the active floodplain surfaces in order to portray the true constraints on fluvial processes.

  7. Biodiversity of zooplankton communities in the Upper Paraná River floodplain: interannual variation from long-term studies.

    PubMed

    Lansac-Tôha, F A; Bonecker, C C; Velho, L F M; Simões, N R; Dias, J D; Alves, G M; Takahashi, E M

    2009-06-01

    We investigated the effect of interannual variation of hydrosedimentological regime and connectivity on the zooplankton biodiversity in the Upper Paraná River floodplain. Zooplankton samplings were undertaken between 2000 and 2007, in different environments of the floodplain, including connected and isolated floodplain lakes, backwaters, rivers and channels. The zooplankton included 541 species. Rotifers showed the highest species richness and abundance. Among the zooplankton species, 71 represent new occurrence records for the floodplain. The species accumulation curve showed a continuous increase in gamma diversity, demonstrating the importance of long-term research for accurate knowledge of biodiversity in heterogeneous and dynamic ecosystems, such as the floodplains. Interannual beta diversity among studied years indicated a lesser alteration in community composition in 2001, when a long limnophase period was observed. In most of the environments, the highest species richness values were related to the greatest flooding amplitudes. Flooding amplitude, which is associated with connectivity, favors faunal exchange amongst the environments and between the pelagic and littoral zones. This explains the occurrence of both planktonic and non-planktonic species within the community. On the other hand, mean zooplankton abundance values were higher when a long isolation period occurred. Differences between the potamophase and limnophase amplitude associated with connectivity among the environments were the most important factors for the structure and dynamics of the zooplankton community in the Upper Paraná River floodplain.

  8. Environmental and climatic factors associated with epizootic ulcerative syndrome (EUS) in fish from the Zambezi floodplains, Zambia.

    PubMed

    Choongo, K; Hang'ombe, B; Samui, K L; Syachaba, M; Phiri, H; Maguswi, C; Muyangaali, K; Bwalya, G; Mataa, L

    2009-10-01

    This study was conducted to determine environmental and climatic factors associated with Epizootic Ulcerative Syndrome (EUS) in fish in the Zambezi floodplains. EUS is a fish disease that causes economic loses to the fishing industry. Streambed colour in affected water was rusty-, reddish- or yellowish- brown and pH 4.5-6.0 while pH of non affected water was 7.2. The rusty-brown precipitate on fish gills was positive for Prussian blue iron stain. Therefore, predisposing factors for EUS in the Zambezi floodplains were the acidification of ground water during drought years and eventual contamination of surface water during the floods of 2006/2007.

  9. The Internal Structure of Positive and Negative Affect: A Confirmatory Factor Analysis of the PANAS

    ERIC Educational Resources Information Center

    Tuccitto, Daniel E.; Giacobbi, Peter R., Jr.; Leite, Walter L.

    2010-01-01

    This study tested five confirmatory factor analytic (CFA) models of the Positive Affect Negative Affect Schedule (PANAS) to provide validity evidence based on its internal structure. A sample of 223 club sport athletes indicated their emotions during the past week. Results revealed that an orthogonal two-factor CFA model, specifying error…

  10. 28 CFR 0.191 - Changes which affect the overall structure of the Department.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 28 Judicial Administration 1 2010-07-01 2010-07-01 false Changes which affect the overall structure of the Department. 0.191 Section 0.191 Judicial Administration DEPARTMENT OF JUSTICE ORGANIZATION OF THE DEPARTMENT OF JUSTICE Sections and Subunits § 0.191 Changes which affect the overall...

  11. Hydrological Controls on Macrophyte Productivity in the Amazon Floodplain Wetlands

    NASA Astrophysics Data System (ADS)

    Silva, T. S.; Novo, E. M.; Melack, J. M.

    2013-05-01

    The Amazon River floodplain is an important source of atmospheric CO2 and CH4, but the relative contribution of allochthonous and autochthonous sources to floodplain emissions is still uncertain. Macrophytes comprise an important carbon source, growing during both low and high water conditions, and averaging 5,000 g.m-2.yr-1 in dry weight. The controls exerted by the annual flooding on macrophyte productivity result from two opposing mechanisms: the "horizontal expansion" of plant stands during low water levels and the stem elongation ("vertical growth") promoted by rising water levels. As studies suggest more frequent and intense droughts for the Amazon, determining how these mechanisms interact to control macrophyte net primary productivity (NPP) can lead to a better understanding of the effects of extreme hydrological conditions on autochthonous carbon fixation in the Amazon floodplain. Our study combines remote sensing estimates of macrophyte cover, in situ measurements of macrophyte biomass, historical water level records, and statistical modeling and simulation to answer 1) how plant horizontal expansion and vertical growth respond to inter-annual flooding variability, 2) how these responses modulate annual NPP, and 3) how climatic changes will affect the contribution of macrophytes to the carbon budget of the Amazon floodplain. Biomass data was collected along a stretch of the Lower Amazon Floodplain, at monthly intervals in 2004, and a time series of Radarsat-1 and EOS-MODIS images was acquired for the same area for the 2003-2005 period. Daily river stage data was acquired from the Brazilian National Water Agency (ANA) for the Óbidos station, covering the 1970 - 2011 period. Macrophyte cover was estimated for each available image in the series, using a multitemporal object-based image analysis algorithm. Empirical regression models were used to model the relationship between flood levels and both plant biomass and cover area, and combined into a semi

  12. Cyanobacteria enhance methylmercury production: a hypothesis tested in the periphyton of two lakes in the Pantanal floodplain, Brazil.

    PubMed

    Lázaro, Wilkinson L; Guimarães, Jean Remy D; Ignácio, Aurea R A; Da Silva, Carolina J; Díez, Sergi

    2013-07-01

    The toxic potential of mercury (Hg) in aquatic systems is due to the presence and production of methylmercury (MeHg). Recent studies in tropical floodplain environments showed that periphyton associated with the roots of aquatic macrophytes produce MeHg. Periphyton communities are the first link in the food chain and one of the main MeHg sources in aquatic environments. The aim of this work was to test the hypotheses that the algal community structure affects potential methylation, and ecologically distinct communities with different algal and bacterial densities directly affect the formation of MeHg in the roots of macrophytes. To evaluate these, net MeHg production in the roots of Eichhornia crassipes in relation to the taxonomic structure of associated periphytic algae was evaluated. Macrophyte root samples were collected in the dry and flood season from two floodplain lakes in the Pantanal (Brazil). These lakes have different ecological conditions as a function of their lateral hydrological connectivity with the Paraguay River that is different during times of drought. Results indicated that MeHg production was higher in the flood season than in the dry season. MeHg production rates were higher in the disconnected lake in comparison to the connected lake during the dry season. MeHg production exhibited a strong positive co-variation with cyanobacteria abundance (R(2)=0.78; p<0.0001 in dry; R(2)=0.40; p=0.029 in flood) and with total algal biomass (R(2)=0.86; p<0.0001), and a negative co-variation with Zygnemaphyceae (R(2)=0.50; p=0.0018) in the lake community in dry season. This indicates that ecological conditions that favour the establishment and development of cyanobacteria are associated with higher rates of methylation in aquatic systems. This suggests that cyanobacteria could be a proxy for sites of MeHg production in some natural aquatic environments.

  13. Geomorphic adjustment to hydrologic modifications along a meandering river: Implications for surface flooding on a floodplain

    NASA Astrophysics Data System (ADS)

    Edwards, Brandon L.; Keim, Richard F.; Johnson, Erin L.; Hupp, Cliff R.; Marre, Saraline; King, Sammy L.

    2016-09-01

    Responses of large regulated rivers to contemporary changes in base level are not well understood. We used field measurements and historical analysis of air photos and topographic maps to identify geomorphic trends of the lower White River, Arkansas, USA, in the 70 years following base-level lowering at its confluence with the Mississippi River and concurrent with flood control by dams. Incision was identified below a knickpoint area upstream of St. Charles, AR, and increases over the lowermost ~90 km of the study site to ~2 m near the confluence with the Mississippi River. Mean bankfull width increased by 30 m (21%) from 1930 to 2010. Bank widening appears to be the result of flow regulation above the incision knickpoint and concomitant with incision below the knickpoint. Hydraulic modeling indicated that geomorphic adjustments likely reduced flooding by 58% during frequent floods in the incised, lowermost floodplain affected by backwater flooding from the Mississippi River and by 22% above the knickpoint area. Dominance of backwater flooding in the incised reach indicates that incision is more important than flood control on the lower White River in altering flooding and also suggests that the Mississippi River may be the dominant control in shaping the lower floodplain. Overall, results highlight the complex geomorphic adjustment in large river-floodplain systems in response to anthropogenic modifications and their implications, including reduced river-floodplain connectivity.

  14. Creating a national scale floodplain map for the United States using soil information

    NASA Astrophysics Data System (ADS)

    Merwade, V.; Du, L.; Sangwan, N.

    2015-12-01

    Floods are the most damaging of all natural disasters, adversely affecting millions of lives and causing financial losses worth billions of dollars every year across the globe. Flood inundation maps play a key role in the assessment and mitigation of potential flood hazards. However, there are several communities in the United States where flood risk maps are not available due to the lack of the resources needed to create such maps through the conventional modeling approach. The objective of this study is to develop and examine an economical alternative approach to floodplain mapping using widely available gSSURGO soil data in the United States. The gSSURGO dataset is used to create floodplain maps for the entire United States by using attributes related to soil taxonomy, flood frequency and geomorphic description. For validation, the flood extents obtained from the soil data are compared with existing maps, including the Federal Emergency Management Agency (FEMA) issued Flood Insurance Rate Maps (FIRM), flood extents observed during past floods, and other flood maps derived using Digital Elevation Models (DEMs). Preliminary results show that overlap between the SSURGO based floodplain maps and FEMA maps range from 65 to 90 percent. While these results are promising, a more comprehensive validation of these maps must be conducted. The soil based approach floodplain mapping approach offers an objective, economical and faster alternative in areas where detailed flood modeling and mapping has not been conducted.

  15. School and Classroom Goal Structures: Effects on Affective Responses in Physical Education

    ERIC Educational Resources Information Center

    Barkoukis, Vassilis; Koidou, Eirini; Tsorbatzoudis, Haralambos; Grouios, George

    2012-01-01

    The current study examined the relative impact of school and classroom goal structures on students' affective responses and the mediating role of motivation. The sample of the study consisted of 368 high school students, who completed measures of school and classroom goal structures, motivational regulations in physical education, boredom, and…

  16. Methane flux from the Central Amazonian Floodplain

    NASA Technical Reports Server (NTRS)

    Bartlett, Karen B.; Crill, Patrick M.; Sebacher, Daniel I.; Harriss, Robert C.; Wilson, John O.; Melack, John M.

    1987-01-01

    A total of 186 methane measurements from the three primary Amazon floodplain environments of open water lakes, flood forests, and floating grass mats were made over the period 18 July through 2 September 1985. These data indicate that emissions were lowest over open water lakes. Flux from flooded forests and grass mats was significantly higher. At least three transport processes contribute to tropospheric emissions: ebullition from sediments, diffusion along the concentration gradient from sediment to overlaying water to air, and transport through the roots and stems of aquatic plants. Measurements indicate that the first two of these processes are most significant. It was estimated that on the average bubbling makes up 49% of the flux from open water, 54% of that from flooded forests, and 64% of that from floating mats. If the measurements were applied to the entire Amazonian floodplain, it is calculated that the region could supply up to 12% of the estimated global natural sources of methane.

  17. Hydrologic connectivity of floodplains, northern Missouri: implications for management and restoration of floodplain forest communities in disturbed landscapes

    USGS Publications Warehouse

    Jacobson, R.; Faust, T.

    2014-01-01

    Hydrologic connectivity between the channel and floodplain is thought to be a dominant factor determining floodplain processes and characteristics of floodplain forests. We explored the role of hydrologic connectivity in explaining floodplain forest community composition along streams in northern Missouri, USA. Hydrologic analyses at 20 streamgages (207–5827 km2 area) document that magnitudes of 2-year return floods increase systematically with increasing drainage area whereas the average annual number and durations of floodplain-connecting events decrease. Flow durations above the active-channel shelf vary little with increasing drainage area, indicating that the active-channel shelf is in quasi-equilibrium with prevailing conditions. The downstream decrease in connectivity is associated with downstream increase in channel incision. These relations at streamflow gaging stations are consistent with regional channel disturbance patterns: channel incision increases downstream, whereas upstream reaches have either not incised or adjusted to incision by forming new equilibrium floodplains. These results provide a framework to explain landscape-scale variations in composition of floodplain forest communities in northern Missouri. Faust () had tentatively explained increases of flood-dependent tree species, and decreases of species diversity, with a downstream increase in flood magnitude and duration. Because frequency and duration of floodplain-connecting events do not increase downstream, we hypothesize instead that increases in relative abundance of flood-dependent trees at larger drainage area result from increasing size of disturbance patches. Bank-overtopping floods at larger drainage area create large, open, depositional landforms that promoted the regeneration of shade-intolerant species. Higher tree species diversity in floodplains with small drainage areas is associated with non-incised floodplains that are frequently connected to their channels and

  18. 76 FR 17427 - Notice of Submission of Proposed Information Collection to OMB; Floodplain Management and...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-03-29

    ... URBAN DEVELOPMENT Notice of Submission of Proposed Information Collection to OMB; Floodplain Management... funds for projects within floodplains or wetlands provide information indicating compliance with...: Floodplain Management and Protection of Wetlands. OMB Approval Number: 2506-0151. Form Numbers:...

  19. 75 FR 82041 - Notice of Proposed Information Collection: Comment Request; Floodplain Management and Protection...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-12-29

    ... URBAN DEVELOPMENT Notice of Proposed Information Collection: Comment Request; Floodplain Management and... Notice also lists the following information: Title of Proposal: Floodplain Management and Protection of..., ``Floodplain Management,'' and Executive Order 11990, ``Protection of Wetlands.'' Each respondent that...

  20. Quantitative model of the growth of floodplains by vertical accretion

    USGS Publications Warehouse

    Moody, J.A.; Troutman, B.M.

    2000-01-01

    A simple one-dimensional model is developed to quantitatively predict the change in elevation, over a period of decades, for vertically accreting floodplains. This unsteady model approximates the monotonic growth of a floodplain as an incremental but constant increase of net sediment deposition per flood for those floods of a partial duration series that exceed a threshold discharge corresponding to the elevation of the floodplain. Sediment deposition from each flood increases the elevation of the floodplain and consequently the magnitude of the threshold discharge resulting in a decrease in the number of floods and growth rate of the floodplain. Floodplain growth curves predicted by this model are compared to empirical growth curves based on dendrochronology and to direct field measurements at five floodplain sites. The model was used to predict the value of net sediment deposition per flood which best fits (in a least squares sense) the empirical and field measurements; these values fall within the range of independent estimates of the net sediment deposition per flood based on empirical equations. These empirical equations permit the application of the model to estimate of floodplain growth for other floodplains throughout the world which do not have detailed data of sediment deposition during individual floods. Copyright (C) 2000 John Wiley and Sons, Ltd.

  1. A spatial simulation model for forest succession in the Upper Mississippi River floodplain

    USGS Publications Warehouse

    Yin, Y.; Wu, Y.; Bartell, S.M.

    2009-01-01

    A Markov-chain transition model (FORSUM) and Monte Carlo simulations were used to simulate the succession patterns and predict a long-term impact of flood on the forest structure and growth in the floodplain of the Upper Mississippi River and Illinois River. Model variables, probabilities, functions, and parameters were derived from the analysis of two comprehensive field surveys conducted in this floodplain. This modeling approach describes the establishment, growth, competition, and death of individual trees for modeled species on a 10,000-ha landscape with spatial resolution of 1 ha. The succession characteristics of each Monte Carlo simulation are summed up to describe forest development and dynamics on a landscape level. FORSUM simulated the impacts of flood intensity and frequency on species composition and dynamics in the Upper Mississippi River floodplain ecosystem. The model provides a useful tool for testing hypotheses about forest succession and enables ecologists and managers to evaluate the impacts of flood disturbances and ecosystem restoration on forest succession. The simulation results suggest that the Markov-chain Monte Carlo method is an efficient tool to help organize the existing data and knowledge of forest succession into a system of quantitative predictions for the Upper Mississippi River floodplain ecosystem. ?? 2009 Elsevier B.V.

  2. A comparison of small-mammal communities in a desert riparian floodplain

    USGS Publications Warehouse

    Ellison, Laura E.; van Riper, Charles, III

    1998-01-01

    We compared small-mammal communities between inactive floodplain and actively flooded terraces of riparian habitat in the Verde Valley of central Arizona. We used species diversity, abundance, weight of adult males, number of juveniles, number of reproductively active individuals, longevity, residency status, and patterns of microhabitat use to compare the two communities. Although abundances of small mammals tended to be higher in the active floodplain, species diversity was greater in the inactive floodplain. Results were inconsistent with our initial prediction that actively flooded riparian habitat acts as a species source, whereas inactive floodplain acts as a sink or dispersal site for small mammals. Within each habitat type, we found evidence of significant microhabitat separation among the three most abundant small-mammal species (Peromyscus boylii, P. eremicus, and Neotoma albigula). Percent cover by annual and perennial grasses and shrubs, substrate, and frequency of shrubs, trees, and debris were significant determinants of small-mammal distribution within a habitat type. We found that the three most abundant species selected a nonrandom subset of available habitat. Nonrandom use of habitat and microhabitat separation were the two most important mechanisms structuring small-mammal communities in riparian habitat of central Arizona.

  3. Geomorphic Framework to assess changes to aquatic habitat due to flow regulation and channel and floodplain alteration, Cedar River, Washington

    USGS Publications Warehouse

    Gendaszek, Andrew S.; Magirl, Christopher S.; Czuba, Christiana R.; Konrad, Christopher P.; Little, Rand

    2010-01-01

    Flow regulation, bank armoring, and floodplain alteration since the early 20th century have contributed to significant changes in the hydrologic regime and geomorphic processes of the Cedar River in Washington State. The Cedar River originates in the Cascade Range, provides drinking water to the Seattle metropolitan area, and supports several populations of anadromous salmonids. Flow regulation currently has limited influence on the magnitude, duration, and timing of high-flow events, which affect the incubation of salmonids as well as the production and maintenance of their habitat. Unlike structural changes to the channel and floodplain, flow regulation may be modified in the short-term to improve the viability of salmon populations. An understanding of the effects of flow regulation on those populations must be discerned over a range of scales from individual floods that affect the size of individual year classes to decadal high flow regime that influences the amount and quality of channel and off-channel habitat available for spawning and rearing. We present estimates of reach-scale sediment budgets and changes to channel morphology derived from historical orthoimagery, specific gage analyses at four long-term streamflow-gaging stations to quantify trends in aggradation, and hydrologic statistics of the magnitude and duration of peak streamflows. These data suggest a gradient of channel types from unconfined, sediment-rich segments to confined, sediment-poor segments that are likely to have distinct responses to high flows. Particle-size distribution data and longitudinal water surface and streambed profiles for the 56 km downstream of Chester Morse Lake measured in 2010 show the spatial extent of preferred salmonid habitat along the Cedar River. These historical and current data constitute a geomorphic framework to help assess different river management scenarios for salmonid habitat and population viability. PDF version of a presentation on changes to aquatic

  4. Floodplain ecohydrology: Climatic, anthropogenic, and local physical controls on partitioning of water sources to riparian trees

    PubMed Central

    Singer, Michael Bliss; Sargeant, Christopher I; Piégay, Hervé; Riquier, Jérémie; Wilson, Rob J S; Evans, Cristina M

    2014-01-01

    Seasonal and annual partitioning of water within river floodplains has important implications for ecohydrologic links between the water cycle and tree growth. Climatic and hydrologic shifts alter water distribution between floodplain storage reservoirs (e.g., vadose, phreatic), affecting water availability to tree roots. Water partitioning is also dependent on the physical conditions that control tree rooting depth (e.g., gravel layers that impede root growth), the sources of contributing water, the rate of water drainage, and water residence times within particular storage reservoirs. We employ instrumental climate records alongside oxygen isotopes within tree rings and regional source waters, as well as topographic data and soil depth measurements, to infer the water sources used over several decades by two co-occurring tree species within a riparian floodplain along the Rhône River in France. We find that water partitioning to riparian trees is influenced by annual (wet versus dry years) and seasonal (spring snowmelt versus spring rainfall) fluctuations in climate. This influence depends strongly on local (tree level) conditions including floodplain surface elevation and subsurface gravel layer elevation. The latter represents the upper limit of the phreatic zone and therefore controls access to shallow groundwater. The difference between them, the thickness of the vadose zone, controls total soil moisture retention capacity. These factors thus modulate the climatic influence on tree ring isotopes. Additionally, we identified growth signatures and tree ring isotope changes associated with recent restoration of minimum streamflows in the Rhône, which made new phreatic water sources available to some trees in otherwise dry years. Key Points Water shifts due to climatic fluctuations between floodplain storage reservoirs Anthropogenic changes to hydrology directly impact water available to trees Ecohydrologic approaches to integration of hydrology afford new

  5. Assessment of flood-induced changes of phytoplankton along a river-floodplain system using the morpho-functional approach.

    PubMed

    Mihaljević, Melita; Spoljarić, Dubravka; Stević, Filip; Zuna Pfeiffer, Tanja

    2013-10-01

    In this research, we aimed to find out how the differences in hydrological connectivity between the main river channel and adjacent floodplain influence the changes in phytoplankton community structure along a river-floodplain system. The research was performed in the River Danube floodplain (Croatian river section) in the period 2008-2009 characterised by different flooding pattern on an annual time scale. By utilising the morpho-functional approach and multivariate analyses, the flood-derived structural changes of phytoplankton were analysed. The lake stability during the isolation phase triggered the specific pattern of morpho-functional groups (MFG) which were characterised by cyanobacterial species achieving very high biomass. Adversely, the high water turbulence in the lake during the frequent and extreme flooding led to evident similarity between lake and river assemblages. Besides different diatom species (groups of small and large centrics and pennates), which are the most abundant representatives in the river phytoplankton, many other groups such as cryptophytes and colonial phytomonads appeared to indicate altered conditions in the floodplain driven by flooding. Having different functional properties, small centric diatom taxa sorted to only one MFG cannot clearly reflect environmental changes that are shown by the species-level pattern. Disadvantages in using the MFG approach highlight that it is still necessary to combine it with taxonomical approach in monitoring of phytoplankton in the river-floodplain ecosystems.

  6. Dynamics of Murray-Darling floodplain forests under multiple stressors: The past, present, and future of an Australian icon

    NASA Astrophysics Data System (ADS)

    Mac Nally, Ralph; Cunningham, Shaun C.; Baker, Patrick J.; Horner, Gillis J.; Thomson, James R.

    2011-12-01

    We review the human actions, proximal stressors and ecological responses for floodplain forests Australia's largest river system—the Murray-Darling Basin. A conceptual model for the floodplain forests was built from extensive published information and some unpublished results for the system, which should provide a basis for understanding, studying and managing the ecology of floodplains that face similar environmental stresses. Since European settlement, lowlands areas of the basin have been extensively cleared for agriculture and remnant forests heavily harvested for timber. The most significant human intervention is modification of river flows, and the reduction in frequency, duration and timing of flooding, which are compounded by climate change (higher temperatures and reduced rainfall) and deteriorating groundwater conditions (depth and salinity). This has created unfavorable conditions for all life-history stages of the dominant floodplain tree (Eucalyptus camaldulensis Dehnh.). Lack of extensive flooding has led to widespread dieback across the Murray River floodplain (currently 79% by area). Management for timber resources has altered the structure of these forests from one dominated by large, widely spreading trees to mixed-aged stands of smaller pole trees. Reductions in numbers of birds and other vertebrates followed the decline in habitat quality (hollow-bearing trees, fallen timber). Restoration of these forests is dependent on substantial increases in the frequency and extent of flooding, improvements in groundwater conditions, re-establishing a diversity of forest structures, removal of grazing and consideration of these interacting stressors.

  7. Spectrometric analyses in comparison to the physiological condition of heavy metal stressed floodplain vegetation in a standardised experiment

    NASA Astrophysics Data System (ADS)

    Götze, Christian; Jung, András; Merbach, Ines; Wennrich, Rainer; Gläßer, Cornelia

    2010-06-01

    Floodplain ecosystems are affected by flood dynamics, nutrient supply as well as anthropogenic activities. Heavy metal pollution poses a serious environmental challenge. Pollution transfer from the soil to vegetation is still present at the central location of Elbe River, Germany. The goal of this study was to assess and separate the current heavy metal contamination of the floodplain ecosystem, using spectrometric field and laboratory measurements. A standardized pot experiment with floodplain vegetation in differently contaminated soils provided the basis for the measurements. The dominant plant types of the floodplains are: Urtica dioica, Phalaris arundinacea and Alopecurus pratensis, these were also chemically analysed. Various vegetation indices and methods were used to estimate the red edge position, to normalise the spectral curve of the vegetation and to investigate the potential of different methods for separating plant stress in floodplain vegetation. The main task was to compare spectral bands during phenological phases to find a method to detect heavy metal stress in plants. A multi-level algorithm for the curve parameterisation was developed. Chemo-analytical and ecophysiological parameters of plants were considered in the results and correlated with spectral data. The results of this study show the influence of heavy metals on the spectral characteristics of the focal plants. The developed method (depth CR1730) showed significant relationship between the plants and the contamination.

  8. Applicability of the flood-pulse concept in a temperate floodplain river ecosystem: Thermal and temporal components

    USGS Publications Warehouse

    Schramm, H.L.; Eggleton, M.A.

    2006-01-01

    Annual growth increments were calculated for blue catfish (Ictalurus furcatus) and flathead catfish (Pylodictis olivaris) from the lower Mississippi River (LMR) to assess hypothesized relationships between fish growth and floodplain inundation as predicted by the Flood-Pulse Concept. Variation in catfish growth increment was high for all age classes of both species, and growth increments were not consistently related to various measures of floodplain inundation. However, relationships became stronger, and usually direct, when water temperature was integrated with area and duration of floodplain inundation. Relationships were significant for four of six age classes for blue catfish, a species known to utilize floodplain habitats. Though similar in direction, relationships were weaker for flathead catfish, which is considered a more riverine species. Our results indicate the Flood-Pulse Concept applies more strongly to temperate floodplain-river ecosystems when thermal aspects of flood pulses are considered. We recommend that future management of the LMR should consider ways to 'recouple' the annual flood and thermal cycles. An adaptive management approach will allow further determination of important processes affecting fisheries production in the LMR. Copyright ?? John Wiley & Sons, Ltd.

  9. Floodplain and wetlands assessment of the White Oak Creek Embayment

    SciTech Connect

    Not Available

    1991-07-01

    This report describes the proposed methods for dealing with contaminants that have accumulated in White Oak Creek, White Oak Lake, and the White Oak Creek Embayment as a result of process releases and discharges from the Oak Ridge National Laboratory. Alternative methods of cleaning up the area which were considered in accordance with regulatory guidelines are listed, and information supporting the selected methods is provided. Also included are results of a site survey conducted at the White Oak Creek Embayment and the expected effects of the proposed control structures on the floodplain and wetlands. The appendix contains figures showing the nine cross-sections of the stream channel surveyed during studies of the White Oak Creek area.

  10. Channelization and floodplain forests: Impacts of accelerated sedimentation and valley plug formation on floodplain forests of the Middle Fork Forked Deer River, Tennessee, USA

    USGS Publications Warehouse

    Oswalt, S.N.; King, S.L.

    2005-01-01

    We evaluated the severe degradation of floodplain habitats resulting from channelization and concomitant excessive coarse sedimentation on the Middle Fork Forked Deer River in west Tennessee from 2000 to 2003. Land use practices have resulted in excessive sediment in the tributaries and river system eventually resulting in sand deposition on the floodplain, increased overbank flooding, a rise in the groundwater table, and ponding of upstream timber. Our objectives were to: (1) determine the composition of floodplain vegetation communities along the degraded river reach, (2) to isolate relationships among these communities, geomorphic features, and environmental variables and (3) evaluate successional changes based on current stand conditions. Vegetation communities were not specifically associated with predefined geomorphic features; nevertheless, hydrologic and geomorphic processes as a result of channelization have clearly affected vegetation communities. The presence of valley plugs and continued degradation of upstream reaches and tributaries on the impacted study reach has arrested recovery of floodplain plant communities. Historically common species like Liquidambar styraciflua L. and Quercus spp. L. were not important, with importance values (IV) less than 1, and occurred in less than 20% of forested plots, while Acer rubrum L., a disturbance-tolerant species, was the most important species on the site (IV = 78.1) and occurred in 87% of forested plots. The results of this study also indicate that channelization impacts on the Middle Fork Forked Deer River are more temporally and spatially complex than previously described for other river systems. Rehabilitation of this system necessitates a long-term, landscape-scale solution that addresses watershed rehabilitation in a spatially and temporally hierarchical manner. ?? 2005 Elsevier B.V. All rights reserved.

  11. Insights into geomorphic and vegetation spatial patterns within dynamic river floodplains using soft classification approaches

    NASA Astrophysics Data System (ADS)

    Guneralp, I.; Filippi, A. M.; Guneralp, B.; You, M.

    2014-12-01

    Lowland rivers in broad alluvial floodplains create one of the most dynamic landscapes, governed by multiple, and commonly nonlinear, interactions among geomorphic, hydrologic, and ecologic processes. Fluvial landforms and land-cover patches composing the floodplains of lowland rivers vary in their shapes and sizes because of variations in vegetation biomass, topography, and soil composition (e.g., of abandoned meanders versus accreting bars) across space. Such floodplain heterogeneity, in turn, influences future river-channel evolution by creating variability in channel-migration rates. In this study, using Landsat 5 Thematic Mapper data and alternative image-classification approaches, we investigate geomorphic and vegetation spatial patterns in a dynamic large tropical river. Specifically, we examine the spatial relations between river-channel planform and fluvial-landform and land-cover patterns across the floodplain. We classify the images using both hard and soft classification algorithms. We characterize the structure of geomorphic landform and vegetation components of the floodplain by computing a range of class-level landscape metrics based on the classified images. Results indicate that comparable classification accuracies are accrued for the inherently hard and (hardened) soft classification images, ranging from 89.8% to 91.8% overall accuracy. However, soft classification images provide unique information regarding spatially-varying similarities and differences in water-column properties of oxbow lakes and the main river channel. Proximity analyses, where buffer zones along the river with distances corresponding to 5, 10, and 20 river-channel widths are constructed, reveal that the average size of forest patches first increase away from the river banks but they become sparse after a distance of 10 channel widths away from the river.

  12. Flood variability recorded by crevasse-splay sedimentation of large river floodplains

    NASA Astrophysics Data System (ADS)

    Hackney, C. R.; Darby, S. E.; Aalto, R. E.; Parsons, D. R.; Clayton, A.; Schwendel, A.; Leyland, J.; Nicholas, A. P.; Best, J.

    2015-12-01

    During rapid rise flood events, crevasse-splay complexes are a key conduit through which sediment and water are passed from the main channel onto the floodplain, particularly for large rivers. These crevasse-splay systems may therefore be key loci of floodplain sedimentation, as well as conditioning the location of avulsions. As such they may preserve climatic signals within the depositional record of large alluvial rivers. Despite recent advances in our capabilities to model the development and evolution of these systems, our understanding of the passage, storage and reworking of water and sediment across them remains relatively poor. A key limitation concerns the point that, since floodplain topography is a first-order control on the hydrodynamics of crevasse-splays, publicly available topographic data sets (e.g. SRTM, ASTER) are currently unable to resolve key processes at the necessary spatial resolution. Here we employ Structure-from-Motion (SfM) on low-level aerial photography to obtain high-resolution (3m grid cell) georectified topographic data (horizontal error = 0.02 m; vertical error = 0.2 m) for a representative crevasse-splay complex (27 km2) located along the Mekong River, Cambodia. We use the coupled hydrodynamic and morphodynamic model, Delft-3D to simulate sedimentation patterns for a series of idealised and observed rapid-rise flood events. We model floodplain deposition and erosion and validate simulated spatial and temporal variations against observed patterns of sedimentation determined through analysis of 210Pb geochronology of a network of floodplain cores and in-situ, post-event surface scrapings.

  13. Coevolution of floodplain and riparian forest dynamics on large, meandering rivers

    NASA Astrophysics Data System (ADS)

    Stella, J. C.; Riddle, J. D.; Battles, J. J.

    2012-12-01

    On large meandering rivers, riparian forests coevolve with the floodplains that support them. Floodplain characteristics such as local disturbance regime, deposition rates and sediment texture drive plant community dynamics, which in turn feed back to the abiotic processes. We investigated floodplain and riparian forest coevolution along the along the Sacramento River (California, USA), a large, mediterranean-climate river that has been extensively regulated for 70 years, but whose 160-km middle reach (Red Bluff to Colusa) retains some channel mobility and natural forest stands. Guided by maps of floodplain change over time and current vegetation cover, we conducted an extensive forest inventory and chronosequence analysis to quantify how abiotic conditions and forest structural characteristics such as tree density, basal area and biomass vary with floodplain age. We inventoried 285 fixed-area plots distributed across 19 large point bars within vegetation patches ranging in age from 4 to 107 years. Two successional trajectories were evident: (1) shifting species dominance over time within forested areas, from willow to cottonwood to walnut, boxelder and valley oak; and (2) patches of shrub willow (primarily Salix exigua) that maintained dominance throughout time. Sediment accretion was reduced in the persistent willow plots compared to the successional forest stands, suggesting an association between higher flood energy and arrested succession. Forested stands 40-60 years old were the most extensive across the chronosequence in terms of floodplain area, and supported the highest biomass, species diversity, and functional wildlife habitat. These stands were dominated by Fremont cottonwood (Populus fremontii) and reached their maxima in terms of tree size and biomass at age 50 years. The persistent willow stands reached their structural maxima earlier (32 years) and supported lower biomass. Basal area and abundance of large trees decreased in stands >90 years old

  14. Climatic seasonality may affect ecological network structure: food webs and mutualistic networks.

    PubMed

    Takemoto, Kazuhiro; Kanamaru, Saori; Feng, Wenfeng

    2014-07-01

    Ecological networks exhibit non-random structural patterns, such as modularity and nestedness, which determine ecosystem stability with species diversity and connectance. Such structure-stability relationships are well known. However, another important perspective is less well understood: the relationship between the environment and structure. Inspired by theoretical studies that suggest that network structure can change due to environmental variability, we collected data on a number of empirical food webs and mutualistic networks and evaluated the effect of climatic seasonality on ecological network structure. As expected, we found that climatic seasonality affects ecological network structure. In particular, an increase in modularity due to climatic seasonality was observed in food webs; however, it is debatable whether this occurs in mutualistic networks. Interestingly, the type of climatic seasonality that affects network structure differs with ecosystem type. Rainfall and temperature seasonality influence freshwater food webs and mutualistic networks, respectively; food webs are smaller, and more modular, with increasing rainfall seasonality. Mutualistic networks exhibit a higher diversity (particularly of animals) with increasing temperature seasonality. These results confirm the theoretical prediction that the stability increases with greater perturbation. Although these results are still debatable because of several limitations in the data analysis, they may enhance our understanding of environment-structure relationships.

  15. 10 CFR 1022.11 - Floodplain or wetland determination.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... safety basis documents as defined at 10 CFR part 830; and (4) DOE environmental documents, e.g., NEPA and... 10 Energy 4 2010-01-01 2010-01-01 false Floodplain or wetland determination. 1022.11 Section 1022.11 Energy DEPARTMENT OF ENERGY (GENERAL PROVISIONS) COMPLIANCE WITH FLOODPLAIN AND...

  16. 10 CFR 1022.11 - Floodplain or wetland determination.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... safety basis documents as defined at 10 CFR part 830; and (4) DOE environmental documents, e.g., NEPA and... 10 Energy 4 2013-01-01 2013-01-01 false Floodplain or wetland determination. 1022.11 Section 1022.11 Energy DEPARTMENT OF ENERGY (GENERAL PROVISIONS) COMPLIANCE WITH FLOODPLAIN AND...

  17. 24 CFR 55.21 - Notification of floodplain hazard.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... designee, e.g., a mortgagor) or a responsible entity subject to 24 CFR part 58 of the hazards of the... 24 Housing and Urban Development 1 2014-04-01 2014-04-01 false Notification of floodplain hazard... Urban Development FLOODPLAIN MANAGEMENT AND PROTECTION OF WETLANDS Procedures for Making...

  18. 76 FR 79145 - Floodplain Management and Protection of Wetlands

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-12-21

    ... URBAN DEVELOPMENT 24 CFR Parts 50, 55, and 58 RIN 2501-AD51 Floodplain Management and Protection of...-wetlands area reviewable action or an year floodplain outside of the amendment) \\1\\ Floodways Coastal high hazard outside coastal 100-year and areas high hazard area within the 500- and floodways year...

  19. 10 CFR 1022.11 - Floodplain or wetland determination.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... safety basis documents as defined at 10 CFR part 830; and (4) DOE environmental documents, e.g., NEPA and... 10 Energy 4 2014-01-01 2014-01-01 false Floodplain or wetland determination. 1022.11 Section 1022.11 Energy DEPARTMENT OF ENERGY (GENERAL PROVISIONS) COMPLIANCE WITH FLOODPLAIN AND...

  20. 10 CFR 1022.11 - Floodplain or wetland determination.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... safety basis documents as defined at 10 CFR part 830; and (4) DOE environmental documents, e.g., NEPA and... 10 Energy 4 2011-01-01 2011-01-01 false Floodplain or wetland determination. 1022.11 Section 1022.11 Energy DEPARTMENT OF ENERGY (GENERAL PROVISIONS) COMPLIANCE WITH FLOODPLAIN AND...

  1. 10 CFR 1022.11 - Floodplain or wetland determination.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... safety basis documents as defined at 10 CFR part 830; and (4) DOE environmental documents, e.g., NEPA and... 10 Energy 4 2012-01-01 2012-01-01 false Floodplain or wetland determination. 1022.11 Section 1022.11 Energy DEPARTMENT OF ENERGY (GENERAL PROVISIONS) COMPLIANCE WITH FLOODPLAIN AND...

  2. Using Canopy Temperature to Infer Hydrologic Processes in Floodplain Forests

    NASA Astrophysics Data System (ADS)

    Lemon, M. G.; Allen, S. T.; Keim, R.; Edwards, B. L.; King, S. L.

    2015-12-01

    Decreased water availability due to hydrologic modifications, groundwater withdrawal, and climate change threaten the hydrological architecture of floodplain forests globally. The relative contributions of different sources of water (e.g., precipitation, surface flooding, and groundwater) to soil moisture on floodplains is poorly constrained, so identification of areas of water stress within a floodplain can provide valuable information about floodplain hydrology. Canopy temperature is a useful indicator of moisture stress and has long been used in agricultural and natural landscapes. Accordingly, thermal infrared (TIR) remote sensing data (spatial resolution of 1 km) from NASA's MODIS sensor was used to examine patterns of spatiotemporal variation in water stress in two floodplain forests over 12 growing seasons. On the upper Sabine River floodplain, Texas, increasing rainfall-derived soil moisture corresponded with increased heterogeneity of LST but there was weak association between river stage and heterogeneity. On the lower White River floodplain, Arkansas, distinct differences in LST between two reaches were observed during low flow years, while little relationship was observed between LST spatial variability and rainfall-derived soil moisture on either reach. The differences in hydrological control on these floodplain ecosystems have important ramifications for varying resilience to climate change and water resource management.

  3. Is Long-Term Structural Priming Affected by Patterns of Experience with Individual Verbs?

    ERIC Educational Resources Information Center

    Kaschak, Michael P.; Borreggine, Kristin L.

    2008-01-01

    Several recent papers have reported long-term structural priming effects in experiments where previous patterns of experience with the double object and prepositional object constructions are shown to affect later patterns of language production for those constructions. The experiments reported in this paper address the extent to which these…

  4. Factors Affecting Higher Order Thinking Skills of Students: A Meta-Analytic Structural Equation Modeling Study

    ERIC Educational Resources Information Center

    Budsankom, Prayoonsri; Sawangboon, Tatsirin; Damrongpanit, Suntorapot; Chuensirimongkol, Jariya

    2015-01-01

    The purpose of the research is to develop and identify the validity of factors affecting higher order thinking skills (HOTS) of students. The thinking skills can be divided into three types: analytical, critical, and creative thinking. This analysis is done by applying the meta-analytic structural equation modeling (MASEM) based on a database of…

  5. Comparative analysis of the soil cover diversity in floodplain areas of the Partizanskaya River valley (Sikhote-Alin Mountains)

    NASA Astrophysics Data System (ADS)

    Nazarkina, A. V.

    2010-12-01

    The regularities of the soil cover formation and pattern in the Partizanskaya River valley (Sikhote-Alin Mountains) were revealed. The diversity of the soil cover was shown to depend on the landscape hydrological zone of the river basin, the structure of the floodplain, and the difference in flooding of the floodplain sections. The comparative assessment of the soil cover diversity using the Shannon index showed that, in the zone of accumulative landscapes, the soil cover diversity of the floodplain sections that were formed under the meandering of the river was higher than the diversity of the soil cover in the sections formed upon branching (furcation) of the channel. The maximum values of the Shannon index and the maximum supply with water characterize the floodplain in the mouth zone of the valley with the most stable conditions of soil formation. The determination of the diversity index for the soil cover and water supply of the floodplain sections is expedient in planning the economic activities in the valley.

  6. Relationship between Microtubule Network Structure and Intracellular Transport in Cultured Endothelial Cells Affected by Shear Stress

    NASA Astrophysics Data System (ADS)

    Kudo, Susumu; Ikezawa, Kenji; Ikeda, Mariko; Tanishita, Kazuo

    Endothelial cells (ECs) that line the inner surface of blood vessels are barriers to the transport of various substances into or from vessel walls, and are continuously exposed to shear stress induced by blood flow in vivo. Shear stress affects the cytoskeleton (e.g., microtubules, microfilaments, intermediate filaments), and affects the transport of macromolecules. Here, the relationship between the microtubule network structure and this transport process for albumin uptake within cultured aortic endothelial cells affected by shear stress was studied. Based on fluorescent images of albumin uptake obtained by using confocal laser scanning microscopy (CLSM), both the microtubule network and albumin uptake in ECs were disrupted by colchicine and were affected by shear stress loading.

  7. Disgust proneness and obsessive-compulsive symptoms in a clinical sample: structural differentiation from negative affect.

    PubMed

    Olatunji, Bunmi O; Ebesutani, Chad; David, Bieke; Fan, Qianqian; McGrath, Patrick B

    2011-10-01

    Although a growing body of research has revealed robust associations between disgust and obsessive-compulsive disorder (OCD) symptoms, there remains a paucity of research examining the specificity of this association in clinical samples. The present study employed structural equation modeling to differentiate disgust from negative affect in the prediction of OCD symptoms in a clinical sample (n=153). Results indicate that disgust and negative affect latent factors were independently related to OCD symptoms. However, when both variables were simultaneously modeled as predictors, latent disgust remained significantly associated with OCD symptoms, whereas the association between latent negative affect and OCD symptoms became nonsignificant. Multiple statistical tests of mediation converged in support of disgust as a significant intervening variable between negative affect and OCD symptoms. The implications of these findings for further delineating the role of individual differences in disgust proneness in the development of OCD are discussed.

  8. Hydrologic conditions, habitat characteristics, and occurrence of fishes in the Apalachicola River floodplain, Florida; second annual report of progress, October 1993-September 1994

    USGS Publications Warehouse

    Light, Helen M.; Darst, Melanie R.; Grubbs, J.W.

    1995-01-01

    This report describes progress and interim results of the second year of a 4-year study. The purpose of the 4-year study is to describe aquatic habitat types in the Apalachicola River floodplain and quantify the amount of habitat inundated by the river at various stages. Final results will be used to determine possible effects of altered flows on floodplain habitats and their associated fish communities. The study is being conducted by the U.S. Geological Survey in cooperation with the Northwest Florida Water Management District as part of a comprehensive study of water needs throughout two large river basins in Florida, Georgia, and Alabama. By the end of the second year, approxi- mately 80 to 90 percent of field data collection was completed. Water levels at 56 floodplain and main channel locations at study sites were read numerous times during low water and once or twice during high water. Rating curves estimating the relationship between stage at a floodplain site and flow of the Apalachicola River at Chattahoochee are presented for 3 sites in the upper river. Elevation, substrate type, and amount of vegetative structure were described at 27 cross sections representing eight different floodplain tributary types at upper, middle, and lower river study sites. A summary of substrate and structure information from all cross sections is presented. Substrate and structure characteristics of floodplain habitats inundated when river flow was at record low flow, mean annual low flow, and mean flow are described for 3 cross sections in the upper river. Digital coverage of high-altitude infra-red aerial photography was processed for use in a Geographic Information System which will be used to map aquatic habitats in the third year of the study. A summary of the literature on fish utilization of floodplain habitats is described. Eighty-one percent of the species collected in the main channel of the Apalachicola River are known to occur in floodplain habitats of eastern

  9. Large-scale dam removal on the Elwha River, Washington, USA: River channel and floodplain geomorphic change

    NASA Astrophysics Data System (ADS)

    East, Amy E.; Pess, George R.; Bountry, Jennifer A.; Magirl, Christopher S.; Ritchie, Andrew C.; Logan, Joshua B.; Randle, Timothy J.; Mastin, Mark C.; Minear, Justin T.; Duda, Jeffrey J.; Liermann, Martin C.; McHenry, Michael L.; Beechie, Timothy J.; Shafroth, Patrick B.

    2015-01-01

    the Elwha River have important ecological implications, affecting aquatic habitat structure, benthic fauna, salmonid fish spawning and rearing potential, and riparian vegetation. The response of the river to dam removal represents a unique opportunity to observe and quantify fundamental geomorphic processes associated with a massive sediment influx, and also provides important lessons for future river-restoration endeavors.

  10. Reprint of: Large-scale dam removal on the Elwha River, Washington, USA: River channel and floodplain geomorphic change

    NASA Astrophysics Data System (ADS)

    East, Amy E.; Pess, George R.; Bountry, Jennifer A.; Magirl, Christopher S.; Ritchie, Andrew C.; Logan, Joshua B.; Randle, Timothy J.; Mastin, Mark C.; Minear, Justin T.; Duda, Jeffrey J.; Liermann, Martin C.; McHenry, Michael L.; Beechie, Timothy J.; Shafroth, Patrick B.

    2015-10-01

    the Elwha River have important ecological implications, affecting aquatic habitat structure, benthic fauna, salmonid fish spawning and rearing potential, and riparian vegetation. The response of the river to dam removal represents a unique opportunity to observe and quantify fundamental geomorphic processes associated with a massive sediment influx, and also provides important lessons for future river-restoration endeavors.

  11. Large-Scale Dam Removal on the Elwha River, Washington, USA: River Channel and Floodplain Geomorphic Change

    NASA Astrophysics Data System (ADS)

    East, A. E.; Pess, G. R.; Bountry, J.; Magirl, C. S.; Ritchie, A. C.; Logan, J. B.; Randle, T. J.; Mastin, M. C.; Duda, J.; Liermann, M. C.; McHenry, M. L.; Beechie, T. J.; Shafroth, P. B.

    2014-12-01

    A substantial increase in fluvial sediment supply causes complex, large-magnitude changes in river and floodplain morphology. Although sedimentary and geomorphic responses to sediment influx are a fundamental part of landscape evolution, few opportunities exist to quantify those processes over field scales. We investigated downstream effects of sediment released during the largest dam removal in history, on the Elwha River, WA, USA, by measuring changes in riverbed elevation and topography, bed-sediment grain size, and channel planform as two dams were removed in stages over two years. As 10.5 million t (7.1 million m3) of sediment was released from two former reservoirs, downstream dispersion of a sediment wave caused widespread bed aggradation of ~1 m (greater where pools filled), changed the river from pool-riffle to braided morphology, and decreased the slope of the lowermost river. The newly deposited sediment, which was finer than most of the pre-dam-removal bed, formed new bars (largely pebble, granule, and sand material), prompting aggradational channel avulsion that increased the channel braiding index by almost 50%. As a result of mainstem bed aggradation, floodplain channels received flow and accumulated new sediment even during low to moderate flow conditions. The river system showed a two- to ten-fold greater geomorphic response to dam removal (bed-elevation change) than it had to a 40-year flood event four years before dam removal. Two years after dam removal began, as the river had started to incise through the new deposits, approximately 1.2 million t of new sediment (~10% of the amount released from the two reservoirs) was stored along 18 river km of the mainstem channel and 25 km of floodplain channels. The Elwha River thus was able to transport most of the released sediment to the river mouth. The geomorphic alterations and changing bed-sediment grain size along the Elwha River have important ecological implications, affecting aquatic habitat

  12. Floodplain geomorphic processes and environmental impacts of human alteration along coastal plain rivers, USA

    USGS Publications Warehouse

    Hupp, C.R.; Pierce, A.R.; Noe, G.B.

    2009-01-01

    Human alterations along stream channels and within catchments have affected fluvial geomorphic processes worldwide. Typically these alterations reduce the ecosystem services that functioning floodplains provide; in this paper we are concerned with the sediment and associated material trapping service. Similarly, these alterations may negatively impact the natural ecology of floodplains through reductions in suitable habitats, biodiversity, and nutrient cycling. Dams, stream channelization, and levee/canal construction are common human alterations along Coastal Plain fluvial systems. We use three case studies to illustrate these alterations and their impacts on floodplain geomorphic and ecological processes. They include: 1) dams along the lower Roanoke River, North Carolina, 2) stream channelization in west Tennessee, and 3) multiple impacts including canal and artificial levee construction in the central Atchafalaya Basin, Louisiana. Human alterations typically shift affected streams away from natural dynamic equilibrium where net sediment deposition is, approximately, in balance with net erosion. Identification and understanding of critical fluvial parameters (e.g., stream gradient, grain-size, and hydrography) and spatial and temporal sediment deposition/erosion process trajectories should facilitate management efforts to retain and/or regain important ecosystem services. ?? 2009, The Society of Wetland Scientists.

  13. Toward a conceptual model of floodplain water table response

    NASA Astrophysics Data System (ADS)

    Jung, M.; Burt, T. P.; Bates, P. D.

    2004-12-01

    Hydrological processes operating within floodplains in temperate midlatitudes have significant implications for water management by controlling pollutant transfer between the catchment and the fluvial system. However, there is a lack of relevant high-resolution data from which the dynamics of floodplain hydrology during flood events can be inferred. A detailed analysis of water table fluctuations during flood events within a typical European lowland floodplain system (River Severn, United Kingdom) is presented. Data collected hourly along two 120-meter-long transects, each comprising four piezometers, plus one river stage sensor, are analyzed for the winter season 1998-1999 using correlation analysis, hysteresis curves, and water table maps. The objective is to develop a conceptual model that provides mechanistic understanding of floodplain water table response during flood events. River stage is shown to be the principal driver of water table fluctuations. Piezometers with similar water table response are identified; their consistent pattern of response in different flood events is attributed to sedimentary and morphological controls on the floodplain and adjoining hillslopes. Deviations from the general pattern are a function of low antecedent soil moisture, which is only a significant factor at the beginning of the winter season, when the floodplain is initially dry. Our conceptual model adopts a kinematic wave process whereby river stage change induces rapid responses of the water table over many tens of meters across the floodplain, associated with flux velocities several orders of magnitude higher than would be expected for Darcian flow. The occurrence of a groundwater ridge within the floodplain dams hillslope drainage and causes the water table to rise at the back of the floodplain. The disappearance of the groundwater ridge during the recession reestablishes hillslope flow into the floodplain, resulting in significant three-dimensional hydraulic gradients

  14. Methane flux from the central Amazonian floodplain

    NASA Technical Reports Server (NTRS)

    Bartlett, Karen B.; Crill, Patrick M.; Sebacher, Daniel I.; Harriss, Robert C.; Wilson, John O.

    1988-01-01

    A total of 186 methane measurements from the three primary Amazon floodplain environments of open water lakes, flood forests, and floating grass mats were made over the period 18 July through 2 September 1985. These data indicate that emissions were lowest over open water lakes. Flux from flooded forests and grass mats was significantly higher. At least three transport processes contribute to tropospheric emissions: ebullition from sediments, diffusion along the concentration gradient from sediment to overlaying water to air, and transport through the roots and stems of aquatic plants. Measurements indicate that the first two of these processes are most significant. It was estimated that on the average bubbling makes up 49 percent of the flux from open water, 54 percent of that from flooded forests, and 64 percent of that from floating mats. If the measurements were applied to the entire Amazonian floodplain, it is calculated that the region could supply up to 12 percent of the estimated global natural sources of methane.

  15. Large-scale dam removal on the Elwha River, Washington, USA: river channel and floodplain geomorphic change

    USGS Publications Warehouse

    East, Amy E.; Pess, George R.; Bountry, Jennifer A.; Magirl, Christopher S.; Ritchie, Andrew C.; Logan, Joshua; Randle, Timothy J.; Mastin, Mark C.; Minear, Justin T.; Duda, Jeffrey J.; Liermann, Martin C.; McHenry, Michael L.; Beechie, Timothy J.; Shafroth, Patrick B.

    2015-01-01

    As 10.5 million t (7.1 million m3) of sediment was released from two former reservoirs, downstream dispersion of a sediment wave caused widespread bed aggradation of ~ 1 m (greater where pools filled), changed the river from pool–riffle to braided morphology, and decreased the slope of the lowermost river. The newly deposited sediment, which was finer than most of the pre-dam-removal bed, formed new bars (largely pebble, granule, and sand material), prompting aggradational channel avulsion that increased the channel braiding index by almost 50%. As a result of mainstem bed aggradation, floodplain channels received flow and accumulated new sediment even during low to moderate flow conditions. The river system showed a two- to tenfold greater geomorphic response to dam removal (in terms of bed elevation change magnitude) than it had to a 40-year flood event four years before dam removal. Two years after dam removal began, as the river had started to incise through deposits of the initial sediment wave, ~ 1.2 million t of new sediment (~ 10% of the amount released from the two reservoirs) was stored along 18 river km of the mainstem channel and 25 km of floodplain channels. The Elwha River thus was able to transport most of the released sediment to the river mouth. The geomorphic alterations and changing bed sediment grain size along the Elwha River have important ecological implications, affecting aquatic habitat structure, benthic fauna, salmonid fish spawning and rearing potential, and riparian vegetation. The response of the river to dam removal represents a unique opportunity to observe and quantify fundamental geomorphic processes associated with a massive sediment influx, and also provides important lessons for future river-restoration endeavors.

  16. Geochemical Controls on the Mobility of Lead and Silver in Tropical Floodplain Sediments.

    NASA Astrophysics Data System (ADS)

    Watson, E. A.; Apte, S. C.; Dietrich, W. E.; Taylor, M. P.

    2005-12-01

    The Strickland River, Papua New Guinea, which is the dominant drainage to the Fly River delta, receives inputs of mine tailings and waste rock from the Porgera gold mine, which is situated at an elevation of 2,500 meters in the upper catchment of the river system. While the contribution to the overall sediment load of the river is small, the mine derived sediments contain elevated concentrations of particulate silver and lead. The vertical core profiles of these elements were used as part of collaborative investigation among an NSF sponsored Margins Source to Sink research group, University of Papua New Guinea researchers, Porgera Joint Venture (PNG), CSIRO (Australia) and Macquarie University (Australia), to map the extent and rate of overbank deposition along the Strickland River. A key question is what proportion of the rivers sediment load is deposited on the lowland floodplain before the river joins the Fly River. An important property of any suitable particulate tracer is its low mobility following deposition. The aim of this study was to investigate the geochemical factors that may affect post-depositional mobility of lead and silver in floodplain sediments. Laboratory modelling studies were conducted to examine the effects of key parameters such as pH, dissolved organic carbon and redox changes resulting from wet/dry cycling of sediments during flooding and drying events. The solid phase speciation of silver and lead in floodplain sediments was also assessed by measurement of acid volatile sulphide concentrations and application of acid leaching procedures. A conceptual model of the geochemical processes affecting particulate silver and lead cycling in floodplain sediments will be presented.

  17. Landscape structure affects specialists but not generalists in naturally fragmented grasslands.

    PubMed

    Miller, Jesse E D; Damschen, Ellen I; Harrison, Susan P; Grace, James B

    2015-12-01

    Understanding how biotic communities respond to landscape spatial structure is critically important for conservation management as natural habitats become increasingly fragmented. However, empirical studies of the effects of spatial structure on plant species richness have found inconsistent results, suggesting that more comprehensive approaches are needed. We asked how landscape structure affects total plant species richness and the richness of a guild of specialized plants in a multivariate context. We sampled herbaceous plant communities at 56 dolomite glades (insular, fire-adapted grasslands) across the Missouri Ozarks, USA, and used structural equation modeling (SEM) to analyze the relative importance of landscape structure, soil resource availability, and fire history for plant communities. We found that landscape spatial structure, defined as the area-weighted proximity of glade habitat surrounding study sites (proximity index), had a significant effect on total plant species richness, but only after we controlled for environmental covariates. Richness of specialist species, but not generalists, was positively related to landscape spatial structure. Our results highlight that local environmental filters must be considered to understand the influence of landscape structure on communities and that unique species guilds may respond differently to landscape structure than the community as a whole. These findings suggest that both local environment and landscape context should be considered when developing management strategies for species of conservation concern in fragmented habitats. PMID:26909437

  18. Landscape structure affects specialists but not generalists in naturally fragmented grasslands

    USGS Publications Warehouse

    Miller, Jesse E.D.; Damschen, Ellen Ingman; Harrison, Susan P.; Grace, James B.

    2015-01-01

    Understanding how biotic communities respond to landscape spatial structure is critically important for conservation management as natural landscapes become increasingly fragmented. However, empirical studies of the effects of spatial structure on plant species richness have found inconsistent results, suggesting that more comprehensive approaches are needed. In this study, we asked how landscape structure affects total plant species richness and the richness of a guild of specialized plants in a multivariate context. We sampled herbaceous plant communities at 56 dolomite glades (insular, fire-adapted grasslands) across the Missouri Ozarks, and used structural equation modeling (SEM) to analyze the relative importance of landscape structure, soil resource availability, and fire history for plant communities. We found that landscape spatial structure-defined as the area-weighted proximity of glade habitat surrounding study sites (proximity index)-had a significant effect on total plant species richness, but only after we controlled for environmental covariates. Richness of specialist species, but not generalists, was positively related to landscape spatial structure. Our results highlight that local environmental filters must be considered to understand the influence of landscape structure on communities, and that unique species guilds may respond differently to landscape structure than the community as a whole. These findings suggest that both local environment and landscape context should be considered when developing management strategies for species of conservation concern in fragmented habitats.

  19. Landscape structure affects specialists but not generalists in naturally fragmented grasslands.

    PubMed

    Miller, Jesse E D; Damschen, Ellen I; Harrison, Susan P; Grace, James B

    2015-12-01

    Understanding how biotic communities respond to landscape spatial structure is critically important for conservation management as natural habitats become increasingly fragmented. However, empirical studies of the effects of spatial structure on plant species richness have found inconsistent results, suggesting that more comprehensive approaches are needed. We asked how landscape structure affects total plant species richness and the richness of a guild of specialized plants in a multivariate context. We sampled herbaceous plant communities at 56 dolomite glades (insular, fire-adapted grasslands) across the Missouri Ozarks, USA, and used structural equation modeling (SEM) to analyze the relative importance of landscape structure, soil resource availability, and fire history for plant communities. We found that landscape spatial structure, defined as the area-weighted proximity of glade habitat surrounding study sites (proximity index), had a significant effect on total plant species richness, but only after we controlled for environmental covariates. Richness of specialist species, but not generalists, was positively related to landscape spatial structure. Our results highlight that local environmental filters must be considered to understand the influence of landscape structure on communities and that unique species guilds may respond differently to landscape structure than the community as a whole. These findings suggest that both local environment and landscape context should be considered when developing management strategies for species of conservation concern in fragmented habitats.

  20. Seasonal dynamics of the shoreline vegetation in the Zapatosa floodplain lake complex, Colombia.

    PubMed

    Schmidt-Mumm, Udo; Janauer, Georg

    2014-09-01

    Floodplain lakes and associated wetlands in tropical dry climates are controlled by pronounced and severe seasonal hydrologic fluctuations. We examined the plant community response to a bimodal flooding pattern in the Zapatosa Floodplain Lake Complex (ZFLC), Northern Colombia. We measured floristic and quantitative change in four sampling periods emphasizing seasonal differences in plant abundance and life-form structure. Of 79 species identified in the lake complex, 52 were used to characterize eight community types via classification and ordination procedures. Results showed that community structure does not change significantly during the flooding/receding stages. But maximum drawdown phase significantly disrupts the aquatic community structure and the exposed shorelines become colonized by ruderal terrestrial plants. Early rainfalls at the beginning of the wet season are emphasized as an important feature of plant regeneration and community development. The general strategy of the ZFLC vegetation can be framed into the flood pulse concept of river-floodplain systems. Thus, plant communities are mainly responding to disturbances and destruction events imposed by extreme water level fluctuations. PMID:25412537

  1. Seasonal dynamics of the shoreline vegetation in the Zapatosa floodplain lake complex, Colombia.

    PubMed

    Schmidt-Mumm, Udo; Janauer, Georg

    2014-09-01

    Floodplain lakes and associated wetlands in tropical dry climates are controlled by pronounced and severe seasonal hydrologic fluctuations. We examined the plant community response to a bimodal flooding pattern in the Zapatosa Floodplain Lake Complex (ZFLC), Northern Colombia. We measured floristic and quantitative change in four sampling periods emphasizing seasonal differences in plant abundance and life-form structure. Of 79 species identified in the lake complex, 52 were used to characterize eight community types via classification and ordination procedures. Results showed that community structure does not change significantly during the flooding/receding stages. But maximum drawdown phase significantly disrupts the aquatic community structure and the exposed shorelines become colonized by ruderal terrestrial plants. Early rainfalls at the beginning of the wet season are emphasized as an important feature of plant regeneration and community development. The general strategy of the ZFLC vegetation can be framed into the flood pulse concept of river-floodplain systems. Thus, plant communities are mainly responding to disturbances and destruction events imposed by extreme water level fluctuations.

  2. Impact of drying and re-flooding of sediment on phosphorus dynamics of river-floodplain systems.

    PubMed

    Schönbrunner, Iris M; Preiner, Stefan; Hein, Thomas

    2012-08-15

    One of the consequences of human impacts on floodplains is a change in sedimentation leading to enhanced floodplain aggradation. Thus, accumulated sediments rich in nutrients might interfere with floodplain restoration. In this study we investigated the phosphorus release behavior of sediments from shallow backwaters of an isolated floodplain of the Danube River situated east of the city of Vienna with the aim to understand the effects of changes in dry/wet cycles on established floodplain sediments. In the light of restoration plans aiming at increased surface water exchange with the river main channel, the response of sediments to frequent alternations between desiccation and inundation periods is a key issue as changes of sediment properties are expected to affect phosphorus release. In order to determine the effect of changing hydrological conditions on internal phosphorus loading, we exposed sediments to different dry/wet treatments in a laboratory experiment. Total phosphorus (TP) release from sediments into the water column increased with increasing duration of dry periods prior to re-wetting. Partial correlation analysis showed significant positive correlations between ΔTP and ΔNH(4)(+) as well as between ΔTP and ΔFe(3+) concentrations (Δ refers to the difference between the final and initial concentration during the wetting period), indicating that enhanced mineralization rates leading to a concomitant release of NH(4)(+) and TP and the reduction of iron hydroxides leading to a concomitant release of Fe(3+) and TP are the mechanisms responsible for the rise in TP. Repeated drying and wetting resulted in elevated phosphorus release. This effect was more pronounced when drying periods led to an 80% reduction in water content, indicating that the degree of drying is a major determinant controlling phosphorus release upon re-wetting. The reconnection of isolated floodplains will favor fluctuating hydrologic conditions and is therefore expected to

  3. Effects of Reduced Summer Precipitation on Productivity and Forage Quality of Floodplain Meadows at the Elbe and the Rhine River

    PubMed Central

    Ludewig, Kristin; Donath, Tobias W.; Zelle, Bianka; Eckstein, R. Lutz; Mosner, Eva; Otte, Annette; Jensen, Kai

    2015-01-01

    Background Floodplain meadows along rivers are semi-natural habitats and depend on regular land use. When used non-intensively, they offer suitable habitats for many plant species including rare ones. Floodplains are hydrologically dynamic ecosystems with both periods of flooding and of dry conditions. In German floodplains, dry periods may increase due to reduced summer precipitation as projected by climate change scenarios. Against this background, the question arises, how the forage quantity and quality of these meadows might change in future. Methods We report results of two field trials that investigated effects of experimentally reduced summer precipitation on hay quantity and quality of floodplain meadows at the Rhine River (2011-2012) and at two Elbe tributaries (2009-2011). We measured annual yield, the amount of hay biomass, and contents of crude protein, crude fibre, energy, fructan, nitrogen, phosphorus, and potassium. Results The annual yield decreased under precipitation reduction at the Rhine River. This was due to reduced productivity in the second cut hay at the Rhine River in which, interestingly, the contents of nitrogen and crude protein increased. The first cut at the Rhine River was unaffected by the treatments. At the Elbe tributaries, the annual yield and the hay quantity and quality of both cuts were only marginally affected by the treatments. Conclusion We conclude that the yield of floodplain meadows may become less reliable in future since the annual yield decreased under precipitation reduction at the Rhine River. However, the first and agriculturally more important cut was almost unaffected by the precipitation reduction, which is probably due to sufficient soil moisture from winter/spring. As long as future water levels of the rivers will not decrease during spring, at least the use of the hay from the first cut of floodplain meadows appears reliable under climate change. PMID:25950730

  4. Impact of drying and re-flooding of sediment on phosphorus dynamics of river-floodplain systems.

    PubMed

    Schönbrunner, Iris M; Preiner, Stefan; Hein, Thomas

    2012-08-15

    One of the consequences of human impacts on floodplains is a change in sedimentation leading to enhanced floodplain aggradation. Thus, accumulated sediments rich in nutrients might interfere with floodplain restoration. In this study we investigated the phosphorus release behavior of sediments from shallow backwaters of an isolated floodplain of the Danube River situated east of the city of Vienna with the aim to understand the effects of changes in dry/wet cycles on established floodplain sediments. In the light of restoration plans aiming at increased surface water exchange with the river main channel, the response of sediments to frequent alternations between desiccation and inundation periods is a key issue as changes of sediment properties are expected to affect phosphorus release. In order to determine the effect of changing hydrological conditions on internal phosphorus loading, we exposed sediments to different dry/wet treatments in a laboratory experiment. Total phosphorus (TP) release from sediments into the water column increased with increasing duration of dry periods prior to re-wetting. Partial correlation analysis showed significant positive correlations between ΔTP and ΔNH(4)(+) as well as between ΔTP and ΔFe(3+) concentrations (Δ refers to the difference between the final and initial concentration during the wetting period), indicating that enhanced mineralization rates leading to a concomitant release of NH(4)(+) and TP and the reduction of iron hydroxides leading to a concomitant release of Fe(3+) and TP are the mechanisms responsible for the rise in TP. Repeated drying and wetting resulted in elevated phosphorus release. This effect was more pronounced when drying periods led to an 80% reduction in water content, indicating that the degree of drying is a major determinant controlling phosphorus release upon re-wetting. The reconnection of isolated floodplains will favor fluctuating hydrologic conditions and is therefore expected to

  5. The structure and size of sensory bursts encode stimulus information but only size affects behavior.

    PubMed

    Marsat, Gary; Pollack, Gerald S

    2010-04-01

    Cricket ultrasound avoidance is a classic model system for neuroethology. Avoidance steering is triggered by high-firing-rate bursts of spikes in the auditory command neuron AN2. Although bursting is common among sensory neurons, and although the detailed structure of bursts may encode information about the stimulus, it is as yet unclear whether this information is decoded. We address this question in two ways: from an information coding point of view, by showing the relationship between stimulus and burst structure; and also from a functional point of view by showing the relationship between burst structure and behavior. We conclude that the burst structure carries detailed temporal information about the stimulus but that this has little impact on the behavioral response, which is affected mainly by burst size.

  6. The structure and size of sensory bursts encode stimulus information but only size affects behavior.

    PubMed

    Marsat, Gary; Pollack, Gerald S

    2010-04-01

    Cricket ultrasound avoidance is a classic model system for neuroethology. Avoidance steering is triggered by high-firing-rate bursts of spikes in the auditory command neuron AN2. Although bursting is common among sensory neurons, and although the detailed structure of bursts may encode information about the stimulus, it is as yet unclear whether this information is decoded. We address this question in two ways: from an information coding point of view, by showing the relationship between stimulus and burst structure; and also from a functional point of view by showing the relationship between burst structure and behavior. We conclude that the burst structure carries detailed temporal information about the stimulus but that this has little impact on the behavioral response, which is affected mainly by burst size. PMID:20213110

  7. Abandoned floodplain plant communities along a regulated dryland river

    USGS Publications Warehouse

    Reynolds, L. V.; Shafroth, Patrick B.; House, P. K.

    2014-01-01

    Rivers and their floodplains worldwide have changed dramatically over the last century because of regulation by dams, flow diversions and channel stabilization. Floodplains no longer inundated by river flows following dam-induced flood reduction comprise large areas of bottomland habitat, but the effects of abandonment on plant communities are not well understood. Using a hydraulic flow model, geomorphic mapping and field surveys, we addressed the following questions along the Bill Williams River, Arizona: (i) What per cent of the bottomland do abandoned floodplains comprise? and (ii) Are abandoned floodplains quantitatively different from adjacent xeric and riparian surfaces in terms of vegetation composition and surface sediment? We found that nearly 70% of active channel and floodplain area was abandoned following dam installation. Abandoned floodplains along the Bill Williams River tend to be similar to each other yet distinct from neighbouring habitats: they have been altered physically from their historic state, leading to distinct combinations of surface sediments, hydrology and plant communities. Abandoned floodplains may transition to xeric communities over time but are likely to retain some riparian qualities as long as there is access to relatively shallow ground water. With expected increases in water demand and drying climatic conditions in many regions, these surfaces and associated vegetation will continue to be extensive in riparian landscapes worldwide

  8. Dynamic meandering in response to upstream perturbations and floodplain formation

    NASA Astrophysics Data System (ADS)

    Schuurman, F.; Shimizu, Y.; Iwasaki, T.; Kleinhans, M. G.

    2016-01-01

    River meandering results from spatially alternating bank erosion and bar growth. Recent flume experiments and theory suggest that a continuous inflow perturbation is a requirement for sustained meandering. Furthermore, flume experiments suggest that bar-floodplain conversion is an additional requirement. Here, we tested the effects of continuous inflow perturbation and bar-floodplain conversion on meander migration using three numerical morphodynamic models: a 1D-model, and two 2D-models with one of them using adaptive moving grid. We focused on the interaction between bars and bends that leads to meander initiation, and the effect of different methods to model bank erosion and floodplain accretion processes on meander migration. The results showed that inflow perturbations have large effects on meander dynamics of high-sinuosity channels, with strong excitation when the inflow is periodically perturbed. In contrast, inflow perturbations have rather small effect in low-sinuosity channels. Steady alternate bars alone are insufficient to cause high-sinuosity meandering. For high-sinuosity meandering, bar-floodplain conversion is required that prevents chute-cutoffs and enhances flow asymmetry, whilst meandering with chute-cutoffs requires merely weak floodplain formation, and braiding occurs without floodplain formation. Thus, this study demonstrated that both dynamic upstream inflow perturbation and bar-floodplain conversion are required for sustained high-sinuosity meandering.

  9. Protein Molecular Structures, Protein SubFractions, and Protein Availability Affected by Heat Processing: A Review

    SciTech Connect

    Yu,P.

    2007-01-01

    The utilization and availability of protein depended on the types of protein and their specific susceptibility to enzymatic hydrolysis (inhibitory activities) in the gastrointestine and was highly associated with protein molecular structures. Studying internal protein structure and protein subfraction profiles leaded to an understanding of the components that make up a whole protein. An understanding of the molecular structure of the whole protein was often vital to understanding its digestive behavior and nutritive value in animals. In this review, recently obtained information on protein molecular structural effects of heat processing was reviewed, in relation to protein characteristics affecting digestive behavior and nutrient utilization and availability. The emphasis of this review was on (1) using the newly advanced synchrotron technology (S-FTIR) as a novel approach to reveal protein molecular chemistry affected by heat processing within intact plant tissues; (2) revealing the effects of heat processing on the profile changes of protein subfractions associated with digestive behaviors and kinetics manipulated by heat processing; (3) prediction of the changes of protein availability and supply after heat processing, using the advanced DVE/OEB and NRC-2001 models, and (4) obtaining information on optimal processing conditions of protein as intestinal protein source to achieve target values for potential high net absorbable protein in the small intestine. The information described in this article may give better insight in the mechanisms involved and the intrinsic protein molecular structural changes occurring upon processing.

  10. Familiarity affects social network structure and discovery of prey patch locations in foraging stickleback shoals

    PubMed Central

    Atton, N.; Galef, B. J.; Hoppitt, W.; Webster, M. M.; Laland, K. N.

    2014-01-01

    Numerous factors affect the fine-scale social structure of animal groups, but it is unclear how important such factors are in determining how individuals encounter resources. Familiarity affects shoal choice and structure in many social fishes. Here, we show that familiarity between shoal members of sticklebacks (Gasterosteus aculeatus) affects both fine-scale social organization and the discovery of resources. Social network analysis revealed that sticklebacks remained closer to familiar than to unfamiliar individuals within the same shoal. Network-based diffusion analysis revealed that there was a strong untransmitted social effect on patch discovery, with individuals tending to discover a task sooner if a familiar individual from their group had previously done so than if an unfamiliar fish had done so. However, in contrast to the effect of familiarity, the frequency with which individuals had previously associated with one another had no effect upon the likelihood of prey patch discovery. This may have been due to the influence of fish on one another's movements; the effect of familiarity on discovery of an empty ‘control’ patch was as strong as for discovery of an actual prey patch. Our results demonstrate that factors affecting fine-scale social interactions can also influence how individuals encounter and exploit resources. PMID:25009061

  11. Floodplain complexity and surface metrics: influences of scale and geomorphology

    USGS Publications Warehouse

    Scown, Murray W.; Thoms, Martin C.; DeJager, Nathan R.

    2015-01-01

    Many studies of fluvial geomorphology and landscape ecology examine a single river or landscape, thus lack generality, making it difficult to develop a general understanding of the linkages between landscape patterns and larger-scale driving variables. We examined the spatial complexity of eight floodplain surfaces in widely different geographic settings and determined how patterns measured at different scales relate to different environmental drivers. Floodplain surface complexity is defined as having highly variable surface conditions that are also highly organised in space. These two components of floodplain surface complexity were measured across multiple sampling scales from LiDAR-derived DEMs. The surface character and variability of each floodplain were measured using four surface metrics; namely, standard deviation, skewness, coefficient of variation, and standard deviation of curvature from a series of moving window analyses ranging from 50 to 1000 m in radius. The spatial organisation of each floodplain surface was measured using spatial correlograms of the four surface metrics. Surface character, variability, and spatial organisation differed among the eight floodplains; and random, fragmented, highly patchy, and simple gradient spatial patterns were exhibited, depending upon the metric and window size. Differences in surface character and variability among the floodplains became statistically stronger with increasing sampling scale (window size), as did their associations with environmental variables. Sediment yield was consistently associated with differences in surface character and variability, as were flow discharge and variability at smaller sampling scales. Floodplain width was associated with differences in the spatial organization of surface conditions at smaller sampling scales, while valley slope was weakly associated with differences in spatial organisation at larger scales. A comparison of floodplain landscape patterns measured at different

  12. Assemblage patterns of fish functional groups relative to habitat connectivity and conditions in floodplain lakes

    USGS Publications Warehouse

    Miyazono, S.; Aycock, J.N.; Miranda, L.E.; Tietjen, T.E.

    2010-01-01

    We evaluated the influences of habitat connectivity and local environmental factors on the distribution and abundance patterns of fish functional groups in 17 floodplain lakes in the Yazoo River Basin, USA. The results of univariate and multivariate analyses showed that species-environmental relationships varied with the functional groups. Species richness and assemblage structure of periodic strategists showed strong and positive correlations with habitat connectivity. Densities of most equilibrium and opportunistic strategists decreased with habitat connectivity. Densities of certain equilibrium and opportunistic strategists increased with turbidity. Forested wetlands around the lakes were positively related to the densities of periodic and equilibrium strategists. These results suggest that decreases in habitat connectivity, forested wetland buffers and water quality resulting from environmental manipulations may cause local extinction of certain fish taxa and accelerate the dominance of tolerant fishes in floodplain lakes. ?? 2010 John Wiley & Sons A/S.

  13. Tree growth and recruitment in a leveed floodplain forest in the Mississippi River Alluvial Valley, USA

    USGS Publications Warehouse

    Gee, Hugo K.W.; King, Sammy L.; Keim, Richard F.

    2014-01-01

    Flooding is a defining disturbance in floodplain forests affecting seed germination, seedling establishment, and tree growth. Globally, flood control, including artificial levees, dams, and channelization has altered flood regimes in floodplains. However, a paucity of data are available in regards to the long-term effects of levees on stand establishment and tree growth in floodplain forests. In this study, we used dendrochronological techniques to reconstruct tree recruitment and tree growth over a 90-year period at three stands within a ring levee in the Mississippi River Alluvial Valley (MAV) and to evaluate whether recruitment patterns and tree growth changed following levee construction. We hypothesized that: (1) sugarberry is increasing in dominance and overcup oak (Quercus lyrata) is becoming less dominant since the levee, and that changes in hydrology are playing a greater role than canopy disturbance in these changes in species dominance; and (2) that overcup oak growth has declined following construction of the levee and cessation of overbank flooding whereas that of sugarberry has increased. Recruitment patterns shifted from flood-tolerant overcup oak to flood-intolerant sugarberry (Celtis laevigata) after levee construction. None of the 122 sugarberry trees cored in this study established prior to the levee, but it was the most common species established after the levee. The mechanisms behind the compositional change are unknown, however, the cosmopolitan distribution of overcup oak during the pre-levee period and sugarberry during the post-levee period, the lack of sugarberry establishment in the pre-levee period, and the confinement of overcup oak regeneration to the lowest areas in each stand after harvest in the post-levee period indicate that species-specific responses to flooding and light availability are forcing recruitment patterns. Overcup oak growth was also affected by levee construction, but in contrast to our hypothesis, growth actually

  14. Modernizing the U.S. Vertical Datum: Effects on Floodplain Mapping

    NASA Astrophysics Data System (ADS)

    Youngman, M.; Childers, V. A.

    2012-12-01

    The current vertical component of the National Spatial Reference system (NSRS), the North American Vertical Datum of 1988 (NAVD 88), provides a height system based upon leveling data and realized on >500,000 monuments. Inherent errors and biases in NAVD 88 have been demonstrated through comparison with the GRACE (Gravity Recovery and Climate Experiment) satellite gravity. In response, NGS launched the Gravity for the Redefinition of the American Vertical Datum (GRAV-D) project in 2008 to replace NAVD88 with a more accurate, gravitationally-based vertical datum by 2022. The goal of the project is to make orthometric heights available to the user community through GNSS measurement that is accurate to 2 cm. GRAV-D's primary thrust involves collecting medium-resolution airborne gravity data over the entire U.S and its territories. Each survey spans approximately a 400 km x 500 km region, large enough for spectral blending with GRACE and GOCE data while the 20 km resolution allows for the evaluation of and spectral blending with surface gravity (terrestrial and marine). Regions are surveyed in the order based upon expected impacts, and the new official datum will be released at the end of the project. Top priorities include Alaska, the Great Lakes, and coastal CONUS. Height changes in these areas may be significant, depending on the application. One major consideration is how changing the datum will affect the diverse fields that use the NSRS. An analysis of one application, floodplain mapping, provided a number of insights into what areas may be more or less affected. The study, The Effects of Modernizing the National Datums on Floodplain Mapping, examined a riverine flood model for a stream in North Carolina and analyzed how products, including the floodplain, would change as a result of the coordinate shift. Data were transformed to proxy datums, which were the most recent available horizontal and vertical datum. The original and transformed data were run through the

  15. Description of floodplains and wetlands, Deaf Smith County site, Texas

    SciTech Connect

    Not Available

    1986-11-01

    Floodplains and wetlands are important features of the Texas Panhandle landscape, and are found on the Deaf Smith County site and in its vicinity. Use or disturbance of floodplains and wetlands in relation to the Civilian Radioactive Waste Management Program is subject to environmental review requirements implementing two Executive Orders. This report provides general information on playa wetlands in the Texas Panhandle, and describes and maps floodplains and wetlands on the Deaf Smith site and in its vicinity. The report is based on the published literature, with information from limited field reconnaissance included.

  16. Geomorphic process and vegetation diversity in the active riverbed and the floodplain in the Kamikochi valley, central Japan

    NASA Astrophysics Data System (ADS)

    Shimazu, H.

    2012-04-01

    The Kamikochi valley is located in a mountainous area in central Japan. The R. Azusa in this valley is a braided river with floodplains. Dense riparian forests cover the floodplains and fragmented small pioneer plant patches and isolated old pioneer trees are distributed in the active riverbed. This study aims to discuss the relationships between geomorphic processes of the river and vegetation diversity. Yearly mapping of the riverbed micro-landforms revealed that channel migrations and landform changes in the active riverbed occurs once every one or several years during a bankfull flood in the rainy season. Germination ages of riparian trees using a dendrochronological technique, their established layers and landform structure were examined to reconstruct floodplain dynamics. Major channel migrations destroyed the riparian forest repeatedly and the recent event occurred about 100 years ago. This caused a longitudinal zonal structure of the riparian forest vegetation, elm-fir forest, mature pioneer forest and young pioneer forests. The young pioneer forest is located alongside the present riverbed. The mature pioneer forest lies between the older elm-fir forests. The pioneer plants germinated simultaneously on the abandoned channel after channel migration. These trees became the mature pioneer forest. Ditches and lobes including boulders are found in the floodplain. The ditches extend parallel to the direction of the present and former channels. The lobes are distributed alongside them. Younger trees under the canopy grow on the lobes in the inner part of the floodplain. These young trees and lobes show that dominant sedimentation process in the floodplain is not lateral flooding, but longitudinal flooding. Sediments from the present channel flew downward through the ditches and were overflowed on the floodplain. This process destroyed the vegetation in and alongside the ditches causing vegetation diversity in the inner part of the riparian forest. Several species

  17. Small but powerful: top predator local extinction affects ecosystem structure and function in an intermittent stream.

    PubMed

    Rodríguez-Lozano, Pablo; Verkaik, Iraima; Rieradevall, Maria; Prat, Narcís

    2015-01-01

    Top predator loss is a major global problem, with a current trend in biodiversity loss towards high trophic levels that modifies most ecosystems worldwide. Most research in this area is focused on large-bodied predators, despite the high extinction risk of small-bodied freshwater fish that often act as apex consumers. Consequently, it remains unknown if intermittent streams are affected by the consequences of top-predators' extirpations. The aim of our research was to determine how this global problem affects intermittent streams and, in particular, if the loss of a small-bodied top predator (1) leads to a 'mesopredator release', affects primary consumers and changes whole community structures, and (2) triggers a cascade effect modifying the ecosystem function. To address these questions, we studied the top-down effects of a small endangered fish species, Barbus meridionalis (the Mediterranean barbel), conducting an enclosure/exclosure mesocosm experiment in an intermittent stream where B. meridionalis became locally extinct following a wildfire. We found that top predator absence led to 'mesopredator release', and also to 'prey release' despite intraguild predation, which contrasts with traditional food web theory. In addition, B. meridionalis extirpation changed whole macroinvertebrate community composition and increased total macroinvertebrate density. Regarding ecosystem function, periphyton primary production decreased in apex consumer absence. In this study, the apex consumer was functionally irreplaceable; its local extinction led to the loss of an important functional role that resulted in major changes to the ecosystem's structure and function. This study evidences that intermittent streams can be affected by the consequences of apex consumers' extinctions, and that the loss of small-bodied top predators can lead to large ecosystem changes. We recommend the reintroduction of small-bodied apex consumers to systems where they have been extirpated, to restore

  18. Small but powerful: top predator local extinction affects ecosystem structure and function in an intermittent stream.

    PubMed

    Rodríguez-Lozano, Pablo; Verkaik, Iraima; Rieradevall, Maria; Prat, Narcís

    2015-01-01

    Top predator loss is a major global problem, with a current trend in biodiversity loss towards high trophic levels that modifies most ecosystems worldwide. Most research in this area is focused on large-bodied predators, despite the high extinction risk of small-bodied freshwater fish that often act as apex consumers. Consequently, it remains unknown if intermittent streams are affected by the consequences of top-predators' extirpations. The aim of our research was to determine how this global problem affects intermittent streams and, in particular, if the loss of a small-bodied top predator (1) leads to a 'mesopredator release', affects primary consumers and changes whole community structures, and (2) triggers a cascade effect modifying the ecosystem function. To address these questions, we studied the top-down effects of a small endangered fish species, Barbus meridionalis (the Mediterranean barbel), conducting an enclosure/exclosure mesocosm experiment in an intermittent stream where B. meridionalis became locally extinct following a wildfire. We found that top predator absence led to 'mesopredator release', and also to 'prey release' despite intraguild predation, which contrasts with traditional food web theory. In addition, B. meridionalis extirpation changed whole macroinvertebrate community composition and increased total macroinvertebrate density. Regarding ecosystem function, periphyton primary production decreased in apex consumer absence. In this study, the apex consumer was functionally irreplaceable; its local extinction led to the loss of an important functional role that resulted in major changes to the ecosystem's structure and function. This study evidences that intermittent streams can be affected by the consequences of apex consumers' extinctions, and that the loss of small-bodied top predators can lead to large ecosystem changes. We recommend the reintroduction of small-bodied apex consumers to systems where they have been extirpated, to restore

  19. Small but Powerful: Top Predator Local Extinction Affects Ecosystem Structure and Function in an Intermittent Stream

    PubMed Central

    Rodríguez-Lozano, Pablo; Verkaik, Iraima; Rieradevall, Maria; Prat, Narcís

    2015-01-01

    Top predator loss is a major global problem, with a current trend in biodiversity loss towards high trophic levels that modifies most ecosystems worldwide. Most research in this area is focused on large-bodied predators, despite the high extinction risk of small-bodied freshwater fish that often act as apex consumers. Consequently, it remains unknown if intermittent streams are affected by the consequences of top-predators’ extirpations. The aim of our research was to determine how this global problem affects intermittent streams and, in particular, if the loss of a small-bodied top predator (1) leads to a ‘mesopredator release’, affects primary consumers and changes whole community structures, and (2) triggers a cascade effect modifying the ecosystem function. To address these questions, we studied the top-down effects of a small endangered fish species, Barbus meridionalis (the Mediterranean barbel), conducting an enclosure/exclosure mesocosm experiment in an intermittent stream where B. meridionalis became locally extinct following a wildfire. We found that top predator absence led to ‘mesopredator release’, and also to ‘prey release’ despite intraguild predation, which contrasts with traditional food web theory. In addition, B. meridionalis extirpation changed whole macroinvertebrate community composition and increased total macroinvertebrate density. Regarding ecosystem function, periphyton primary production decreased in apex consumer absence. In this study, the apex consumer was functionally irreplaceable; its local extinction led to the loss of an important functional role that resulted in major changes to the ecosystem’s structure and function. This study evidences that intermittent streams can be affected by the consequences of apex consumers’ extinctions, and that the loss of small-bodied top predators can lead to large ecosystem changes. We recommend the reintroduction of small-bodied apex consumers to systems where they have been

  20. Elevated atmospheric CO2 levels affect community structure of rice root-associated bacteria

    PubMed Central

    Okubo, Takashi; Liu, Dongyan; Tsurumaru, Hirohito; Ikeda, Seishi; Asakawa, Susumu; Tokida, Takeshi; Tago, Kanako; Hayatsu, Masahito; Aoki, Naohiro; Ishimaru, Ken; Ujiie, Kazuhiro; Usui, Yasuhiro; Nakamura, Hirofumi; Sakai, Hidemitsu; Hayashi, Kentaro; Hasegawa, Toshihiro; Minamisawa, Kiwamu

    2015-01-01

    A number of studies have shown that elevated atmospheric CO2 ([CO2]) affects rice yields and grain quality. However, the responses of root-associated bacteria to [CO2] elevation have not been characterized in a large-scale field study. We conducted a free-air CO2 enrichment (FACE) experiment (ambient + 200 μmol.mol−1) using three rice cultivars (Akita 63, Takanari, and Koshihikari) and two experimental lines of Koshihikari [chromosome segment substitution and near-isogenic lines (NILs)] to determine the effects of [CO2] elevation on the community structure of rice root-associated bacteria. Microbial DNA was extracted from rice roots at the panicle formation stage and analyzed by pyrosequencing the bacterial 16S rRNA gene to characterize the members of the bacterial community. Principal coordinate analysis of a weighted UniFrac distance matrix revealed that the community structure was clearly affected by elevated [CO2]. The predominant community members at class level were Alpha-, Beta-, and Gamma-proteobacteria in the control (ambient) and FACE plots. The relative abundance of Methylocystaceae, the major methane-oxidizing bacteria in rice roots, tended to decrease with increasing [CO2] levels. Quantitative PCR revealed a decreased copy number of the methane monooxygenase (pmoA) gene and increased methyl coenzyme M reductase (mcrA) in elevated [CO2]. These results suggest elevated [CO2] suppresses methane oxidation and promotes methanogenesis in rice roots; this process affects the carbon cycle in rice paddy fields. PMID:25750640

  1. Neonatal handling alters the structure of maternal behavior and affects mother-pup bonding.

    PubMed

    Reis, A R; de Azevedo, M S; de Souza, M A; Lutz, M L; Alves, M B; Izquierdo, I; Cammarota, M; Silveira, P P; Lucion, A B

    2014-05-15

    During early life, a mother and her pups establish a very close relationship, and the olfactory learning of the nest odor is very important for the bond formation. The olfactory bulb (OB) is a structure that plays a fundamental role in the olfactory learning (OL) mechanism that also involves maternal behavior (licking and contact). We hypothesized that handling the pups would alter the structure of the maternal behavior, affect OL, and alter mother-pup relationships. Moreover, changes in the cyclic AMP-response element binding protein phosphorylation (CREB) and neurotrophic factors could be a part of the mechanism of these changes. This study aimed to analyze the effects of neonatal handling, 1 min per day from postpartum day 1 to 10 (PPD 1 to PPD 10), on the maternal behavior and pups' preference for the nest odor in a Y maze (PPD 11). We also tested CREB's phosphorylation and BDNF signaling in the OB of the pups (PPD 7) by Western blot analysis. The results showed that handling alters mother-pups interaction by decreasing mother-pups contact and changing the temporal pattern of all components of the maternal behavior especially the daily licking and nest-building. We found sex-dependent changes in the nest odor preference, CREB and BDNF levels in pups OB. Male pups were more affected by alterations in the licking pattern, and female pups were more affected by changes in the mother-pup contact (the time spent outside the nest and nursing).

  2. The Urban Floodplain as a Focus for Geographical Education.

    ERIC Educational Resources Information Center

    Montz, Burrell E.; And Others

    1989-01-01

    Explains how studying a floodplain can help students analyze the interactions between humans and the physical environment. Analyzes data from two cities in California to demonstrate that housing prices did not rebound after a flood. (GG)

  3. IMPACTS ON FLOODPLAINS BY AN INVASIVE SHRUB, BUDDLEJA DAVIDII

    EPA Science Inventory

    Despite its popularity, the ornamental, Buddleja davidii, a woody shrub of Asian origin, is considered problematic because of its ability to rapidly colonize and dominate floodplain and riparian ecosystems. Dominance during early succession may influence community dynamics and ec...

  4. Forest canopy structural controls over throughfall affect soil microbial community structure in an epiphyte-laden maritime oak stand

    NASA Astrophysics Data System (ADS)

    Van Stan, J. T., II; Rosier, C. L.; Schrom, J. O.; Wu, T.; Reichard, J. S.; Kan, J.

    2014-12-01

    Identifying spatiotemporal influences on soil microbial community (SMC) structure is critical to understanding of patterns in nutrient cycling and related ecological services. Since forest canopy structure alters the spatiotemporal patterning of precipitation water and solute supplies to soils (via the "throughfall" mechanism), is it possible changes in SMC structure variability could arise from modifications in canopy elements? Our study investigates this question by monitoring throughfall water and dissolved ion supply to soils beneath a continuum of canopy structure: from a large gap (0% cover) to heavy Tillandsia usneoides L. (Spanish moss) canopy (>90% cover). Throughfall water supply diminished with increasing canopy cover, yet increased washoff/leaching of Na+, Cl-, PO43-, and SO42- from the canopy to the soils (p < 0.01). Presence of T. usneoides diminished throughfall NO3-, but enhanced NH4+, concentrations supplied to subcanopy soils. The mineral soil horizon (0-10 cm) from canopy gaps, bare canopy, and T. usneoides-laden canopy significantly differed (p < 0.05) in soil chemistry parameters (pH, Ca2+, Mg2+, CEC). PCR-DGGE banding patterns beneath similar canopy covers (experiencing similar throughfall dynamics) also produced high similarities per ANalyses Of SIMilarity (ANO-SIM), and clustered together when analyzed by Nonmetric Multidimensional Scaling (NMDS). Correlation analysis of DGGE banding patterns, throughfall dynamics, and soil chemistry yielded significant correlations (p < 0.05) between fungal communities and soil chemical properties significantly differing between canopy cover types (pH: r2 = 0.50; H+ %-base saturation: r2 = 0.48; Ca2+ %-base saturation: r2 = 0.43). Bacterial community structure correlated with throughfall NO3-, NH4+, and Ca2+ concentrations (r2 = 0.37, p = 0.16). These results suggest that modifications of forest canopy structures are capable of affecting mineral-soil horizon SMC structure via the throughfall mechanism when

  5. Management intensity at field and landscape levels affects the structure of generalist predator communities.

    PubMed

    Rusch, Adrien; Birkhofer, Klaus; Bommarco, Riccardo; Smith, Henrik G; Ekbom, Barbara

    2014-07-01

    Agricultural intensification is recognised as a major driver of biodiversity loss in human-modified landscapes. Several agro-environmental measures at different spatial scales have been suggested to mitigate the negative impact of intensification on biodiversity and ecosystem services. The effect of these measures on the functional structure of service-providing communities remains, however, largely unexplored. Using two distinct landscape designs, we examined how the management options of organic farming at the field scale and crop diversification at the landscape level affect the taxonomic and functional structure of generalist predator communities and how these effects vary along a landscape complexity gradient. Organic farming as well as landscapes with longer and more diversified crop rotations enhanced the activity-density of spiders and rove beetles, but not the species richness or evenness. Our results indicate that the two management options affected the functional composition of communities, as they primarily enhanced the activity-density of functionally similar species. The two management options increased the functional similarity between spider species in regards to hunting mode and habitat preference. Organic farming enhanced the functional similarity of rove beetles. Management options at field and landscape levels were generally more important predictors of community structure when compared to landscape complexity. Our study highlights the importance of considering the functional composition of generalist predators in order to understand how agro-environmental measures at various scales shape community assemblages and ecosystem functioning in agricultural landscapes. PMID:24810324

  6. The use of noncrystallographic symmetry averaging to solve structures from data affected by perfect hemihedral twinning.

    PubMed

    Sabin, Charles; Plevka, Pavel

    2016-03-01

    Hemihedral twinning is a crystal-growth anomaly in which a specimen is composed of two crystal domains that coincide with each other in three dimensions. However, the orientations of the crystal lattices in the two domains differ in a specific way. In diffraction data collected from hemihedrally twinned crystals, each observed intensity contains contributions from both of the domains. With perfect hemihedral twinning, the two domains have the same volumes and the observed intensities do not contain sufficient information to detwin the data. Here, the use of molecular replacement and of noncrystallographic symmetry (NCS) averaging to detwin a 2.1 Å resolution data set for Aichi virus 1 affected by perfect hemihedral twinning is described. The NCS averaging enabled the correction of errors in the detwinning introduced by the differences between the molecular-replacement model and the crystallized structure. The procedure permitted the structure to be determined from a molecular-replacement model that had 16% sequence identity and a 1.6 Å r.m.s.d. for C(α) atoms in comparison to the crystallized structure. The same approach could be used to solve other data sets affected by perfect hemihedral twinning from crystals with NCS.

  7. Predominant floodplain over mountain weathering of Himalayan sediments (Ganga basin)

    NASA Astrophysics Data System (ADS)

    Lupker, Maarten; France-Lanord, Christian; Galy, Valier; Lavé, Jérôme; Gaillardet, Jérôme; Gajurel, Ananta Prasad; Guilmette, Caroline; Rahman, Mustafizur; Singh, Sunil Kumar; Sinha, Rajiv

    2012-05-01

    We present an extensive river sediment dataset covering the Ganga basin from the Himalayan front downstream to the Ganga mainstream in Bangladesh. These sediments were mainly collected over several monsoon seasons and include depth profiles of suspended particles in the river water column. Mineral sorting is the first order control on the chemical composition of river sediments. Taking into account this variability we show that sediments become significantly depleted in mobile elements during their transit through the floodplain. By comparing sediments sampled at the Himalayan front with sediments from the Ganga mainstream in Bangladesh it is possible to budget weathering in the floodplain. Assuming a steady state weathering regime in the floodplain, the weathering of Himalayan sediments in the Gangetic floodplain releases ca. (189 ± 92) × 109 and (69 ± 22) × 109 mol/yr of carbonate bound Ca and Mg to the dissolved load, respectively. Silicate weathering releases (53 ± 18) × 109 and (42 ± 13) × 109 mol/yr of Na and K while the release of silicate Mg and Ca is substantially lower, between ca. 0 and 20 × 109 mol/yr. Additionally, we show that sediment hydration, [H2O+], is a sensitive tracer of silicate weathering that can be used in continental detrital environments, such as the Ganga basin. Both [H2O+] content and the D/H isotopic composition of sediments increases during floodplain transfer in response to mineral hydrolysis and neoformations associated to weathering reactions. By comparing the chemical composition of river sediments across the floodplain with the composition of the eroded Himalayan source rocks, we suggest that the floodplain is the dominant location of silicate weathering for Na, K and [H2O+]. Overall this work emphasizes the role of the Gangetic floodplain in weathering Himalayan sediments. It also demonstrates how detrital sediments can be used as weathering tracers if mineralogical and chemical sorting effects are properly taken into

  8. Floods, floodplains, delta plains — A satellite imaging approach

    NASA Astrophysics Data System (ADS)

    Syvitski, James P. M.; Overeem, Irina; Brakenridge, G. Robert; Hannon, Mark

    2012-08-01

    Thirty-three lowland floodplains and their associated delta plains are characterized with data from three remote sensing systems (AMSR-E, SRTM and MODIS). These data provide new quantitative information to characterize Late Quaternary floodplain landscapes and their penchant for flooding over the last decade. Daily proxy records for discharge since 2002 and for each of the 33 river systems can be derived with novel Advanced Microwave Scanning Radiometer (AMSR-E) methods. A descriptive framework based on analysis of Shuttle Radar Topography Mission (SRTM) data is used to capture the major landscape-scale floodplain elements or zones: 1) container valleys with their long and narrow pathways of largely sediment transit and bypass, 2) floodplain depressions that act as loci for frequent flooding and sediment storage, 3) zones of nodal avulsions common to many continental scale rivers, and often located seaward of container valleys, and 4) coastal floodplains and delta plains that offer both sediment bypass and storage but under the influence of marine processes. The SRTM data allow mapping of smaller-scale architectural elements in unprecedented systematic manner. Floodplain depressions were found to play a major role, which may largely be overlooked in conceptual floodplain models. Lastly, MODIS data (independently and combined with AMSR-E) allows the tracking of flood hydrographs and pathways and sedimentation patterns on a near-daily timescale worldwide. These remote-sensing data show that 85% of the studied major river systems experienced extensive flooding in the last decade. A new quantitative paradigm of floodplain processes, honoring the frequency and extent of floods, can be develop by careful analysis of these new remotely sensed data.

  9. Complex regional pain syndrome type I affects brain structure in prefrontal and motor cortex.

    PubMed

    Pleger, Burkhard; Draganski, Bogdan; Schwenkreis, Peter; Lenz, Melanie; Nicolas, Volkmar; Maier, Christoph; Tegenthoff, Martin

    2014-01-01

    The complex regional pain syndrome (CRPS) is a rare but debilitating pain disorder that mostly occurs after injuries to the upper limb. A number of studies indicated altered brain function in CRPS, whereas possible influences on brain structure remain poorly investigated. We acquired structural magnetic resonance imaging data from CRPS type I patients and applied voxel-by-voxel statistics to compare white and gray matter brain segments of CRPS patients with matched controls. Patients and controls were statistically compared in two different ways: First, we applied a 2-sample ttest to compare whole brain white and gray matter structure between patients and controls. Second, we aimed to assess structural alterations specifically of the primary somatosensory (S1) and motor cortex (M1) contralateral to the CRPS affected side. To this end, MRI scans of patients with left-sided CRPS (and matched controls) were horizontally flipped before preprocessing and region-of-interest-based group comparison. The unpaired ttest of the "non-flipped" data revealed that CRPS patients presented increased gray matter density in the dorsomedial prefrontal cortex. The same test applied to the "flipped" data showed further increases in gray matter density, not in the S1, but in the M1 contralateral to the CRPS-affected limb which were inversely related to decreased white matter density of the internal capsule within the ipsilateral brain hemisphere. The gray-white matter interaction between motor cortex and internal capsule suggests compensatory mechanisms within the central motor system possibly due to motor dysfunction. Altered gray matter structure in dorsomedial prefrontal cortex may occur in response to emotional processes such as pain-related suffering or elevated analgesic top-down control.

  10. Assessing the Value of Information for Identifying Optimal Floodplain Management Portfolios

    NASA Astrophysics Data System (ADS)

    Read, L.; Bates, M.; Hui, R.; Lund, J. R.

    2014-12-01

    Floodplain management is a complex portfolio problem that can be analyzed from an integrated perspective incorporating traditionally structural and nonstructural options. One method to identify effective strategies for preparing, responding to, and recovering from floods is to optimize for a portfolio of temporary (emergency) and permanent floodplain management options. A risk-based optimization approach to this problem assigns probabilities to specific flood events and calculates the associated expected damages. This approach is currently limited by: (1) the assumption of perfect flood forecast information, i.e. implementing temporary management activities according to the actual flood event may differ from optimizing based on forecasted information and (2) the inability to assess system resilience across a range of possible future events (risk-centric approach). Resilience is defined here as the ability of a system to absorb and recover from a severe disturbance or extreme event. In our analysis, resilience is a system property that requires integration of physical, social, and information domains. This work employs a 3-stage linear program to identify the optimal mix of floodplain management options using conditional probabilities to represent perfect and imperfect flood stages (forecast vs. actual events). We assess the value of information in terms of minimizing damage costs for two theoretical cases - urban and rural systems. We use portfolio analysis to explore how the set of optimal management options differs depending on whether the goal is for the system to be risk-adverse to a specified event or resilient over a range of events.

  11. Groundwater dynamics and water budget analysis at a wetland-dominated forested floodplain

    NASA Astrophysics Data System (ADS)

    Foster, S.; Callahan, T. J.; Senn, L.; Shelley, D.

    2013-12-01

    This study investigated the preliminary relationships between groundwater behavior, vegetation communities, and soil characteristics in a mature, protected forested floodplain at Congaree National Park, South Carolina. Time series analysis of groundwater level data were collected hourly at ten different piezometers from 2009 to 2013. Piezometers were screened 4-7 m deep in the surficial aquifer and arrayed from the floodplain bluff along a 3-km, valley-perpendicular transect to Cedar Creek, a local tributary of the Congaree River. Eight of the ten sites were in an unconfined portion of the floodplain aquifer, and the other two sites closer to Cedar Creek were locally confined due to a 1.5 - 3-m thick clay layer above the piezometer screen. Time series analysis, including depth below ground surface, response to storm events, and diurnal evapotranspiration (ET) signals was used to functionally group piezometer sites with similar characteristics. Lithologic logs collected during piezometer installation and forest community structure at each site were inspected to look for relationships to explain groundwater behavior. A separate analysis of ET signals helped assess potential feedbacks between vegetation and groundwater in this wetland-dominated setting. This project stemmed from hydrology class trips to Congaree National Park sponsored by the park's education and outreach program. Students learned field methods and data collection, management, and analysis techniques to reinforce hydrology concepts and principles.

  12. Assessment of groundwater input and water quality changes impacting natural vegetation in the Loxahatchee River and floodplain ecosystem, Florida

    USGS Publications Warehouse

    Orem, William H.; Swarzenski, Peter W.; McPherson, Benjamin F.; Hedgepath, Marion; Lerch, Harry E.; Reich, Christopher; Torres, Arturo E.; Corum, Margo D.; Roberts, Richard E.

    2007-01-01

    The Loxahatchee River and Estuary are small, shallow, water bodies located in southeastern Florida. Historically, the Northwest Branch (Fork) of the Loxahatchee River was primarily a freshwater system. In 1947, the river inlet at Jupiter was dredged for navigation and has remained permanently open since that time. Drainage patterns within the basin have also been altered significantly due to land development, road construction (e.g., Florida Turnpike), and construction of the C-18 and other canals. These anthropogenic activities along with sea level rise have resulted in significant adverse impacts on the ecosystem over the last several decades, including increased saltwater encroachment and undesired vegetation changes in the floodplain. The problem of saltwater intrusion and vegetation degradation in the Loxahatchee River may be partly induced by diminished freshwater input, from both surface water and ground water into the River system. The overall objective of this project was to assess the seasonal surface water and groundwater interaction and the influence of the biogeochemical characteristics of shallow groundwater and porewater on vegetation health in the Loxahatchee floodplain. The hypothesis tested are: (1) groundwater influx constitutes a significant component of the overall flow of water into the Loxahatchee River; (2) salinity and other chemical constituents in shallow groundwater and porewater of the river floodplain may affect the distribution and health of the floodplain vegetation.

  13. Variations in trace element geochemistry in the Seine River Basin based on floodplain deposits and bed sediments

    USGS Publications Warehouse

    Horowitz, A.J.; Meybeck, Michel; Idlafkih, Z.; Biger, E.

    1999-01-01

    Between 1990 and 1995 a series of bed sediment, suspended sediment and fresh floodplain samples were collected within the Seine River Basin, in France, to evaluate variations in trace element geochemistry. Average background trace element levels for the basin were determined from the collection and subsequent analyses of bed sediment samples from small rural watersheds and from a prehistoric (5000 BP) site in Paris. Concentrations are relatively low, and similar to those observed for fine-grained bed sediments from unaffected areas in the United States and Canada. However, the concentrations are somewhat higher than the reference levels presently adopted by French water authorities for areas north of the Seine Basin, which have similar bedrock lithologies. Downstream trace element variations were monitored in 1994 and 1995 using fresh surficial floodplain samples that were collected either as dried deposits a few days after peak discharge, or immediately after peak discharge (under ??? 30 cm of water). Chemical comparisons between fresh floodplain deposits, and actual suspended sediments collected during flood events, indicate that, with some caveats, the former can be used as surrogates for the latter. The floodplain sediment chemical data indicate that within the Seine Basin, from the relatively unaffected headwaters through heavily affected urban streams, trace element concentrations vary by as much as three orders of magnitude. These trace element changes appear to be the result of both increases in population as well as concomitant increases in industrial activity. This article is a US government work and is in the public domain in the United States.

  14. Sharing the floodplain: Mediated modeling for environmental management

    USGS Publications Warehouse

    Metcalf, S.S.; Wheeler, E.; BenDor, T.K.; Lubinski, S.J.; Hannon, B.M.

    2010-01-01

    Complex ecosystems, such as the Upper Mississippi River (UMR), present major management challenges. Such systems often provide a range of ecosystem services that are differentially valued by stakeholders representing distinct interests (e.g., agriculture, conservation, navigation) or institutions (e.g., federal and state agencies). When no single entity has the knowledge or authority to resolve conflicts over shared resource use, stakeholders may struggle to jointly understand the scope of the problem and to reach reasonable compromises. This paper explores mediated modeling as a group consensus building process for understanding relationships between ecological, economic and cultural well-being in the UMR floodplain. We describe a workshop structure used to engage UMR stakeholders that may be extended to resource use conflicts in other complex ecosystems. We provide recommendations for improving on these participatory methods in structuring future efforts. In conclusion, we suggest that tools which facilitate collaborative learning, such as mediated modeling, need to be incorporated at an institutional level as a vital element of integrated ecosystem management. ?? 2008 Elsevier Ltd.

  15. Large scale floodplain mapping using a hydrogeomorphic method

    NASA Astrophysics Data System (ADS)

    Nardi, F.; Yan, K.; Di Baldassarre, G.; Grimaldi, S.

    2013-12-01

    Floodplain landforms are clearly distinguishable as respect to adjacent hillslopes being the trace of severe floods that shaped the terrain. As a result digital topography intrinsically contains the floodplain information, this works presents the results of the application of a DEM-based large scale hydrogeomorphic floodplain delineation method. The proposed approach, based on the integration of terrain analysis algorithms in a GIS framework, automatically identifies the potentially frequently saturated zones of riparian areas by analysing the maximum flood flow heights associated to stream network nodes as respect to surrounding uplands. Flow heights are estimated by imposing a Leopold's law that scales with the contributing area. Presented case studies include the floodplain map of large river basins for the entire Italian territory , that are also used for calibrating the Leopold scaling parameters, as well as additional large international river basins in different climatic and geomorphic characteristics posing the base for the use of such approach for global floodplain mapping. The proposed tool could be useful to detect the hydrological change since it can easily provide maps to verify the flood impact on human activities and vice versa how the human activities changed in floodplain areas at large scale.

  16. Numerical simulation of overbank processes in topographically complex floodplain environments

    NASA Astrophysics Data System (ADS)

    Nicholas, A. P.; Mitchell, C. A.

    2003-03-01

    This article presents results from an investigation of the hydraulic characteristics of overbank flows on topographically-complex natural river floodplains. A two-dimensional hydraulic model that solves the depth-averaged shallow water form of the Navier-Stokes equations is used to simulate an overbank flow event within a multiple channel reach of the River Culm, Devon, UK. Parameterization of channel and floodplain roughness by the model is evaluated using monitored records of main channel water level and point measurements of floodplain flow depth and unit discharge. Modelled inundation extents and sequences are assessed using maps of actual inundation patterns obtained using a Global Positioning System, observational evidence and ground photographs. Simulation results suggest a two-phase model of flooding at the site, which seems likely to be representative of natural floodplains in general. Comparison of these results with previous research demonstrates the complexity of overbank flows on natural river floodplains and highlights the limitations of laboratory flumes as an analogue for these environments. Despite this complexity, frequency distributions of simulated depth, velocity and unit discharge data closely follow a simple gamma distribution model, and are described by a shape parameter () that exhibits clear systematic trends with changing discharge and floodplain roughness. Such statistical approaches have the potential to provide the basis for computationally efficient flood routing and overbank sedimentation models.

  17. Environmental physiology of a small marsupial inhabiting arid floodplains.

    PubMed

    Warnecke, L; Cooper, C E; Geiser, F; Withers, P C

    2010-09-01

    Giles' planigale (Planigale gilesi) is among the smallest extant marsupials and inhabits deep soil cracks in arid floodplains. We examined whether its physiology shows specific adaptations to its extreme habitat. Metabolic rate, body temperature, evaporative water loss and thermal conductance were measured for eight planigales (average mass 9 g) exposed to four different ambient temperatures ranging from 10 degrees C to 32 degrees C. Water economy and respiratory variables were measured for the first time in this species. All of these standard physiological variables conformed to allometrically-predicted values for a marsupial. All variables were significantly affected by ambient temperature, except tidal volume and dry thermal conductance. Metabolic rate increased substantially at low ambient temperatures, as required to maintain a relatively constant body temperature of about 32-34 degrees C. This increased oxygen demand was accommodated by increased ventilation rather than increased oxygen extraction. Planigales had a comparatively high point of relative water economy of 19.1 degrees C, consistent with their small body size and arid habitat. Torpor reduced energy expenditure by 79% and evaporative water loss by 62%. Our study suggests that torpor use, along with behavioural adaptations, suffice for P. gilesi to live underground in arid habitats without further physiological adaptations.

  18. Effects of alluvial knickpoint migration on floodplain ecology and geomorphology

    NASA Astrophysics Data System (ADS)

    Larsen, Annegret; May, Jan-Hendrick

    2016-04-01

    Alluvial knickpoints are well described as erosional mechanism within discontinuous ephemeral streams in the semi-arid SW USA. However, alluvial knickpoints occur globally in a wide range of settings and of climate zones, including temperate SE Australia, subtropical Africa, and tropical Australia. Much attention has been given in the scientific literature to the trigger mechanisms of alluvial knickpoints, which can be summarized as: i) threshold phenomena, ii) climate variability and iii) land-use change, or to a combination of these factors. Recently, studies have focused on the timescale of alluvial knickpoint retreat, and the processes, mechanisms and feedbacks with ecology, geomorphology and hydrology. In this study, we compile data from a global literature review with a case study on a tropical river system in Australia affected by re-occurring, fast migrating (140 myr-1) alluvial knickpoint. We highlight the importance of potential water table declines due to channel incision following knickpoint migration, which in turn leads to the destabilization of river banks, and a shift in floodplain vegetation and fire incursion. We hypothesize that the observed feedbacks might also help to understand the broader impacts of alluvial knickpoint migration in other regions, and might explain the drastic effects of knickpoint migration on land cover and land-use in semi-arid areas.

  19. Analysis of factors affecting satisfaction level on problem based learning approach using structural equation modeling

    NASA Astrophysics Data System (ADS)

    Hussain, Nur Farahin Mee; Zahid, Zalina

    2014-12-01

    Nowadays, in the job market demand, graduates are expected not only to have higher performance in academic but they must also be excellent in soft skill. Problem-Based Learning (PBL) has a number of distinct advantages as a learning method as it can deliver graduates that will be highly prized by industry. This study attempts to determine the satisfaction level of engineering students on the PBL Approach and to evaluate their determinant factors. The Structural Equation Modeling (SEM) was used to investigate how the factors of Good Teaching Scale, Clear Goals, Student Assessment and Levels of Workload affected the student satisfaction towards PBL approach.

  20. Concrete modelling for expertise of structures affected by alkali aggregate reaction

    SciTech Connect

    Grimal, E.; Sellier, A.; Multon, S.; Le Pape, Y.; Bourdarot, E.

    2010-04-15

    Alkali aggregate reaction (AAR) affects numerous civil engineering structures and causes irreversible expansion and cracking. In order to control the safety level and the maintenance cost of its hydraulic dams, Electricite de France (EDF) must reach better comprehension and better prediction of the expansion phenomena. For this purpose, EDF has developed a numerical model based on the finite element method in order to assess the mechanical behaviour of damaged structures. The model takes the following phenomena into account: concrete creep, the stress induced by the formation of AAR gel and the mechanical damage. A rheological model was developed to assess the coupling between the different phenomena (creep, AAR and anisotropic damage). Experimental results were used to test the model. The results show the capability of the model to predict the experimental behaviour of beams subjected to AAR. In order to obtain such prediction, it is necessary to take all the phenomena occurring in the concrete into consideration.

  1. Clonal structure affects the assembling behavior in the Japanese queenless ant Pristomyrmex punctatus

    NASA Astrophysics Data System (ADS)

    Nishide, Yudai; Satoh, Toshiyuki; Hiraoka, Tuyosi; Obara, Yoshiaki; Iwabuchi, Kikuo

    2007-10-01

    The queenless ant Pristomyrmex punctatus (Hymenoptera: Myrmicinae) has a unique society that differs from those of other typical ants. This species does not have a queen, and the workers lay eggs and produce their clones parthenogenetically. However, a colony of these ants does not always comprise members derived from a single clonal line. In this study, we examined whether P. punctatus changes its “assembling behavior” based on colony genetic structure. We prepared two subcolonies—a larger one comprising 200 individuals and a smaller one comprising 100 individuals; these subcolonies were established from a single stock colony. We investigated whether these subcolonies assemble into a single nest. The genetically monomorphic subcolonies (single clonal line) always fused into a single nest; however, the genetically polymorphic subcolonies (multiple clonal lines) did not tend to form a single colony. The present study is the first to demonstrate that the colony genetic structure significantly affects social viscosity in social insects.

  2. Dioecy, more than monoecy, affects plant spatial genetic structure: the case study of Ficus

    PubMed Central

    Nazareno, Alison G; Alzate-Marin, Ana L; Pereira, Rodrigo Augusto S

    2013-01-01

    In this analysis, we attempt to understand how monoecy and dioecy drive spatial genetic structure (SGS) in plant populations. For this purpose, plants of the genus Ficus were used as a comparative model due to their particular characteristics, including high species diversity, variation in life histories, and sexual systems. One of the main issues we assessed is whether dioecious fig tree populations are more spatially genetically structured than monoecious populations. Using the Sp statistic, which allows for quantitative comparisons among different studies, we compared the extent of SGS between monoecious and dioecious Ficus species. To broaden our conclusions we used published data on an additional 27 monoecious and dioecious plant species. Furthermore, genetic diversity analyses were performed for two monoecious Ficus species using 12 microsatellite markers in order to strengthen our conclusions about SGS. Our results show that dioecy, more than monoecy, significantly contributes to SGS in plant populations. On average, the estimate of Sp was six times higher for dioecious Ficus species than monoecious Ficus species and it was two times higher in dioecious than monoecious plant species. Considering these results, we emphasize that the long-distance pollen dispersal mechanism in monoecious Ficus species seems to be the dominant factor in determining weak spatial genetic structure, high levels of genetic diversity, and lack of inbreeding. Although Ficus constitute a model species to study SGS, a more general comparison encompassing a wider range of plants is required in order to better understand how sexual systems affect genetic structure. PMID:24223285

  3. Structural changes in emulsion-bound bovine beta-lactoglobulin affect its proteolysis and immunoreactivity.

    PubMed

    Marengo, Mauro; Miriani, Matteo; Ferranti, Pasquale; Bonomi, Francesco; Iametti, Stefania; Barbiroli, Alberto

    2016-07-01

    Adsorption on the surface of sub-micrometric oil droplets resulted in significant changes in the tertiary structure of bovine beta-lactoglobulin (BLG), a whey protein broadly used as a food ingredient and a major food allergen. The adsorbed protein had increased sensitivity to trypsin, and increased immunoreactivity towards specific monoclonal antibodies. In spite of the extensive tryptic breakdown of emulsion-bound BLG, some sequence stretches in BLG became trypsin-insensitive upon absorption of the protein on the fat droplets. As a consequence - at contrast with free BLG - proteolysis of emulsion-bound BLG did not decrease the immunoreactivity of the protein, and some of the large peptides generated by trypsinolysis of emulsion-bound BLG were still recognizable by specific monoclonal antibodies. Structural changes occurring in emulsion-bound BLG and their consequences are discussed in comparison with those occurring when the tertiary structure of BLG is modified by lipophilic salts, by urea, or upon interaction with solid hydrophobic surfaces. Such a comparison highlights the relevance of situation-specific structural modifications, that in turn may affect physiologically relevant features of the protein. PMID:27085639

  4. An investigation of factors affecting the entry of radon into structures on the Island of Guam

    SciTech Connect

    Kladder, D.L.; Burkhart, J.F.; Thorburn, M.S.

    1995-12-31

    Factors affecting the entry of radon-222 gas into structures on the Island of Guam were investigated during the summer of 1993. Research findings indicated that radon transport into buildings on Guam, and perhaps in other tropical areas, is driven by sub-grade soil pressure (positive with respect to atmospheric pressure) rather than interior buildings vacuums. Immediate and substantive increases in indoor radon concentrations were associated with environmental effects of wind and rain. Radon entry, and hence indoor radon concentrations, is significantly greater during the rainy season as opposed to the dry season. In the absence of mechanically induced interior vacuums in buildings, external environmental forces creating sub-slab pressures are the predominant factor in affecting radon entry in Guam. Indoor radon potentials can be correlated to the locations where the underlying geology is limestone. Furthermore, the radon source appears to be within the first few feet of the surface of these limestones rather than uniformly distributed throughout the limestone. The effects of seismic activity on radon entry are short-lived unless significant damage occurs to a structure. Radon entry during calm weather conditions may also be a function of the rising and falling of ocean tides.

  5. Optimized Structure and Vibrational Properties by Error Affected Potential Energy Surfaces

    PubMed Central

    Zen, Andrea; Zhelyazov, Delyan; Guidoni, Leonardo

    2013-01-01

    The precise theoretical determination of the geometrical parameters of molecules at the minima of their potential energy surface and of the corresponding vibrational properties are of fundamental importance for the interpretation of vibrational spectroscopy experiments. Quantum Monte Carlo techniques are correlated electronic structure methods promising for large molecules, which are intrinsically affected by stochastic errors on both energy and force calculations, making the mentioned calculations more challenging with respect to other more traditional quantum chemistry tools. To circumvent this drawback in the present work, we formulate the general problem of evaluating the molecular equilibrium structures, the harmonic frequencies, and the anharmonic coefficients of an error affected potential energy surface. The proposed approach, based on a multidimensional fitting procedure, is illustrated together with a critical evaluation of systematic and statistical errors. We observe that the use of forces instead of energies in the fitting procedure reduces the statistical uncertainty of the vibrational parameters by 1 order of magnitude. Preliminary results based on variational Monte Carlo calculations on the water molecule demonstrate the possibility to evaluate geometrical parameters and harmonic and anharmonic coefficients at this level of theory with an affordable computational cost and a small stochastic uncertainty (<0.07% for geometries and <0.7% for vibrational properties). PMID:24093004

  6. Diversity and structure of AMF communities as affected by tillage in a temperate soil.

    PubMed

    Jansa, J; Mozafar, A; Anken, T; Ruh, R; Sanders, I R; Frossard, E

    2002-10-01

    Arbuscular mycorrhizal fungi (AMF) were studied in differently tilled soils from a long-term field experiment in Switzerland. Diversity and structure of AMF communities were surveyed either directly on spores isolated from the field soil or on spores isolated from trap cultures, planted with different host plants. Single-spore cultures were established from the AMF spores obtained from trap cultures. Identification of the AMF was made by observation of spore morphology and confirmed by sequencing of ITS rDNA. At least 17 recognised AMF species were identified in samples from field and/or trap cultures, belonging to five genera of AMF--Glomus, Gigaspora, Scutellospora, Acaulospora, and Entrophospora. Tillage had a significant influence on the sporulation of some species and non- Glomus AMF tended to be more abundant in the no-tilled soil. The community structure of AMF in the field soil was significantly affected by tillage treatment. However, no significant differences in AMF diversity were detected among different soil tillage treatments. AMF community composition in trap cultures was affected much more by the species of the trap plant than by the original tillage treatment of the field soil. The use of trap cultures for fungal diversity estimation in comparison with direct observation of field samples is discussed.

  7. Diversity and structure of AMF communities as affected by tillage in a temperate soil.

    PubMed

    Jansa, J; Mozafar, A; Anken, T; Ruh, R; Sanders, I R; Frossard, E

    2002-10-01

    Arbuscular mycorrhizal fungi (AMF) were studied in differently tilled soils from a long-term field experiment in Switzerland. Diversity and structure of AMF communities were surveyed either directly on spores isolated from the field soil or on spores isolated from trap cultures, planted with different host plants. Single-spore cultures were established from the AMF spores obtained from trap cultures. Identification of the AMF was made by observation of spore morphology and confirmed by sequencing of ITS rDNA. At least 17 recognised AMF species were identified in samples from field and/or trap cultures, belonging to five genera of AMF--Glomus, Gigaspora, Scutellospora, Acaulospora, and Entrophospora. Tillage had a significant influence on the sporulation of some species and non- Glomus AMF tended to be more abundant in the no-tilled soil. The community structure of AMF in the field soil was significantly affected by tillage treatment. However, no significant differences in AMF diversity were detected among different soil tillage treatments. AMF community composition in trap cultures was affected much more by the species of the trap plant than by the original tillage treatment of the field soil. The use of trap cultures for fungal diversity estimation in comparison with direct observation of field samples is discussed. PMID:12375133

  8. Tropical cyclone rainfall structure affecting indochina peninsula and lower mekong river basin (LMB)

    NASA Astrophysics Data System (ADS)

    CHHIN, Rattana; Joko Trilaksono, Nurjanna; Wahyu Hadi, Tri

    2016-08-01

    Indochina Peninsula is located in between Bay of Bengal (BoB) and South-China Sea (SCS). This region is affected frequently from Tropical Cyclones (TCs) formed in North Indian Ocean (NIO), South-China Sea (SCS), and North West Pacific Ocean (NWP). This research analyzed the structure of the rainfall over Indochina Peninsula and its relationships with TCs from the aforementioned sources. Principle Component Analysis (PCA) was performed to investigate the dominant rainfall area produced from those TCs. Spatial and Temporal structures of rainfall from the TCs is analyzed to understand their propagation. The results show that the dominant TC rainfall area covers Central Vietnam which contributed around 25% to total rainfall in the region. However, the contribution of this TC rainfall over LMB is likely less than 20% where Laos's territory receives highest contribution (20%). Furthermore, from the three source areas, TCs formed in SCS produce the highest rain rate when they develop into typhoon intensity stage of Joint Typhoon Warning Center (JTWC)’s scale. The average duration of TC rainfall over Indochina Peninsula is 81.28 hours, and over LMB is 66.22 hours. Thus, same as other regions in the Indochina Peninsula, LMB is affected by TC rainfall with considerable scales both spatially and temporally that may lead to significant hydrometeorological hazards.

  9. The structure and duplex context of DNA interstrand crosslinks affects the activity of DNA polymerase η

    PubMed Central

    Roy, Upasana; Mukherjee, Shivam; Sharma, Anjali; Frank, Ekaterina G.; Schärer, Orlando D.

    2016-01-01

    Several important anti-tumor agents form DNA interstrand crosslinks (ICLs), but their clinical efficiency is counteracted by multiple complex DNA repair pathways. All of these pathways require unhooking of the ICL from one strand of a DNA duplex by nucleases, followed by bypass of the unhooked ICL by translesion synthesis (TLS) polymerases. The structures of the unhooked ICLs remain unknown, yet the position of incisions and processing of the unhooked ICLs significantly influence the efficiency and fidelity of bypass by TLS polymerases. We have synthesized a panel of model unhooked nitrogen mustard ICLs to systematically investigate how the state of an unhooked ICL affects pol η activity. We find that duplex distortion induced by a crosslink plays a crucial role in translesion synthesis, and length of the duplex surrounding an unhooked ICL critically affects polymerase efficiency. We report the synthesis of a putative ICL repair intermediate that mimics the complete processing of an unhooked ICL to a single crosslinked nucleotide, and find that it provides only a minimal obstacle for DNA polymerases. Our results raise the possibility that, depending on the structure and extent of processing of an ICL, its bypass may not absolutely require TLS polymerases. PMID:27257072

  10. Floodplain Sedimentation in Vegetated Areas of the Elwha River Floodplain, 2012-2014

    NASA Astrophysics Data System (ADS)

    Lauer, J. W.; Polka, J.

    2014-12-01

    The removal of the Elwha and Glines Canyon Dams from the Elwha River, near Port Angeles, Washington, has released a large pulse of sediment into the middle and lower reaches of the Elwha River. This sediment has important geomorphic, hydraulic, and ecological implications. Our project focuses on the deposition of fine sediment on vegetated parts of the Elwha floodplain using field observations of sediment accumulation in combination with a simplified physics numerical model, CAESAR-Lisflood. The floodplain of the Elwha is densely vegetated and in places is characterized by large amounts of local topographic variation. This makes measuring centimeter-scale overbank sedimentation difficult using traditional approaches such as lidar and total-station based cross-section surveys. To address this problem and to provide ground truth for more traditional surveying methods, we set up over 50 short (10-20 m long) cross-sections between sets of flagged trees and surveyed, at 1-meter intervals, ground elevation with respect to a spike set in each section. Nails in the trees ensure that the horizontal position of our measurements do not shift by more than a few centimeters from year to year. This approach allows sediment accumulation to be measured repeatedly with a precision we estimate to be on the order of a few centimeters, allowing us to estimate annual rates of local sedimentation. At a given point on the floodplain, sedimentation should depend significantly on the frequency of inundation. We simulate this for the 2012-2014 period using a CAESAR-Lisflood 2-D numerical model calibrated using a set of continuously recording staff gages. CAESAR-Lisflood uses simplified-physics hydraulic routines to efficiently simulate flow depth and velocity and to drive size-specific sediment transport and morphodynamic change. This allows the model to simulate changes in flood inundation probability for the post- removal period. CAESAR-based hydraulic results are used to interpret our

  11. Limnogeology in Brazil's "forgotten wilderness": a synthesis from the large floodplain lakes of the Pantanal

    USGS Publications Warehouse

    McGlue, Michael M.; Silva, Aguinaldo; Corradini, Fabricio A.; Zani, Hiran; Trees, Mark A.; Ellis, Geoffrey S.; Parolin, Mauro; Swarzenski, Peter W.; Cohen, Andrew S.; Assine, Mario L.

    2011-01-01

    Sediment records from floodplain lakes have a large and commonly untapped potential for inferring wetland response to global change. The Brazilian Pantanal is a vast, seasonally inundated savanna floodplain system controlled by the flood pulse of the Upper Paraguay River. Little is known, however, about how floodplain lakes within the Pantanal act as sedimentary basins, or what influence hydroclimatic variables exert on limnogeological processes. This knowledge gap was addressed through an actualistic analysis of three large, shallow (2- > Si4+ > Ca2+), mildly alkaline, freshwater systems, the chemistries and morphometrics of which evolve with seasonal flooding. Lake sills are bathymetric shoals marked by siliciclastic fans and marsh vegetation. Flows at the sills likely undergo seasonal reversals with the changing stage of the Upper Paraguay River. Deposition in deeper waters, typically encountered in proximity to margin-coincident topography, is dominated by reduced silty-clays with abundant siliceous microfossils and organic matter. Stable isotopes of carbon and nitrogen, plus hydrogen index measured on bulk organic matter, suggest that contributions from algae (including cyanobacteria) and other C3-vegetation dominate in these environments. The presence of lotic sponge spicules, together with patterns of terrigenous sand deposition and geochemical indicators of productivity, points to the importance of the flood pulse for sediment and nutrient delivery to the lakes. Flood-pulse plumes, waves and bioturbation likewise affect the continuity of sedimentation. Short-lived radioisotopes indicate rates of 0.11-0.24 cm year-1 at sites of uninterrupted deposition. A conceptual facies model, developed from insights gained from modern seasonal processes, can be used to predict limnogeological change when the lakes become isolated on the floodplain or during intervals associated with a strengthened flood pulse. Amplification of the seasonal cycle over longer time scales

  12. Applying modified high resolution airborne LiDAR DTM for floodplain mapping

    NASA Astrophysics Data System (ADS)

    Vetter, M.; Jochem, A.; Franke, M.; Schöberl, F.; Stötter, J.; Werthmann, M.

    2009-04-01

    Today, airborne LiDAR derived digital terrain models (DTM) are used in the research context and various scientific disciplines. In hydrology such high resolution DTMs are used for computing flood simulations, calculating roughness maps, floodplain mapping, etc. The presented approach outlines the strength of a LiDAR derived DTM (1m) in comparison to a photogrammetric derived DTM (10m). By implementing an interpolated river bed model, which is derived by using terrestrial measured river cross sections and hence modifying the high resolution DTM for hydraulic task floodplain mapping and modeling routines, could be improved. The river bed interpolation routine includes an automatic bridge detection algorithm to delete bridge pillars in the relevant river cross sections. Furthermore, the position of riverbanks, which are a contributing factor in the field of hydraulic modeling and influence the results of the hydraulic simulations, can be detected. Once the DTM is modified, river cross profiles can be extracted directly on each position along the river axis and can be used as input for hydraulic models. In this study the software HEC-RAS is used to calculate different floodplain areas on the basis of the HQ30, HQ100 and HQ200 flood scenarios, which are calibrated on key data of the flood in August 2005. The comparison of the floodplain area in the city of Innsbruck (Tyrol, Austria), modeled on the basis of a modified LiDAR derived DTM, with those from the HORA study (Hochwasserrisikozonierung Austria), shows remarkable differences. These differences result from (i) the different hydraulic modeling methods and (ii) the used DTMs, which HORA does not consider flood protection measures. The results show that the resolution of the used DTM is the determining factor for modeling adequate floodplain areas whereas the applied hydraulic model has secondary effects. The grade of accuracy attained by this approach is reflected by the numbers ,of flooding affected buildings (e

  13. Ecosystem Function in Amazon Floodplain Wetlands: Climate Variability, Landscape Dynamics and Carbon Biogeochemistry.

    NASA Astrophysics Data System (ADS)

    Silva, T. S. F.; Melack, J. M.; Sousa, R. N. D.; Ferreira-Ferreira, J.; Streher, A. S.; Fragal, E. H.; Furtado, L. F.; Resende, A. F. D.; Luize, B. G.; Rudorff, C.; Queiroz, H. L.; Schongart, J.; Novo, E. M.

    2015-12-01

    Wetlands comprise 14% of the Amazon basin, and are a major component of the hydrological and biogeochemical cycles. Most of these areas correspond to floodplain ecosystems along the Amazon River and its major tributaries, hosting unique vegetation types that are strongly controlled by annual hydrological fluctuations. The combination of strong environmental filtering and active fluvial dynamics results in a highly heterogeneous landscape, and in physiological linkages between climate variability and ecosystem processes. We will show several years of results obtained within the framework of the LBA program, discussing the interplay between hydroclimatic variability, landscape dynamics, ecosystem functioning and carbon biogeochemistry in the Amazon floodplains. Using optical and microwave remote sensing, we assessed the distribution of major vegetation types and flooding regimes at several locations across the floodplain. Strong variability in vegetation distribution can be observed, with high and low várzea forests ranging from 30% and 34%, respectively, at the upper Solimões River, to 6% and 25% at the lower Solimões, while non-forested habitats and lakes increase from a percent cover of 8% and 10% to 28% and 27%, respectively. Strong variability in local flood regimes was also determined for each vegetation type, revealing a gradient of habitats within each floodplain. As tree growth, diversity and phenology are affected by flood duration, we expect local conditions to strongly impact carbon stocks and cycling at the landscape scale. Fluvial processes also disturb forest patches, ensuring a mixture of age distributions in the landscape, with varying species composition, carbon stocks, and carbon uptake rates. Herbaceous vegetation growth responds very rapidly to changes in hydrological conditions, and modeling based on microwave imagery and in situ observations showed expected changes of up to 50% in annual net primary production between regular and extreme

  14. Host species and developmental stage, but not host social structure, affects bacterial community structure in socially polymorphic bees.

    PubMed

    McFrederick, Quinn S; Wcislo, William T; Hout, Michael C; Mueller, Ulrich G

    2014-05-01

    Social transmission and host developmental stage are thought to profoundly affect the structure of bacterial communities associated with honey bees and bumble bees, but these ideas have not been explored in other bee species. The halictid bees Megalopta centralis and M. genalis exhibit intrapopulation social polymorphism, which we exploit to test whether bacterial communities differ by host social structure, developmental stage, or host species. We collected social and solitary Megalopta nests and sampled bees and nest contents from all stages of host development. To survey these bacterial communities, we used 16S rRNA gene 454 pyrosequencing. We found no effect of social structure, but found differences by host species and developmental stage. Wolbachia prevalence differed between the two host species. Bacterial communities associated with different developmental stages appeared to be driven by environmentally acquired bacteria. A Lactobacillus kunkeei clade bacterium that is consistently associated with other bee species was dominant in pollen provisions and larval samples, but less abundant in mature larvae and pupae. Foraging adults appeared to often reacquire L. kunkeei clade bacteria, likely while foraging at flowers. Environmental transmission appears to be more important than social transmission for Megalopta bees at the cusp between social and solitary behavior.

  15. Fish mortality and physicochemistry in a managed floodplain wetland

    USGS Publications Warehouse

    Sargent, J.C.; Galat, D.L.

    2002-01-01

    Patterns of fish mortality and associated physicochemical factors were studied during late spring in a managed wetland canal along the lower Missouri River, Missouri. Mean dawn dissolved oxygen was lower and mean un-ionized ammonia and turbidity were higher during the fish kill than before or after the kill, or than was observed in a nearby wetland canal where no fish kill occurred. Dissolved oxygen at dawn and un-ionized ammonia concentrations were at critically low and high levels respectively, so that both likely contributed to the fish mortality. Timing and magnitude of observed carcasses suggested that Ameiurus melas Rafinesques was the most tolerant species for the sizes observed compared to Ictiobus cyprinellus Valenciennes, Lepomis macrochirus Rafinesque, Cyprinus carpio Linneaus, and Lepomis cyanellus Rafinesque. Decreasing mean lengths of fish carcasses during the fish kill for C. carpio, L. cyanellus, and A. melas, indicate that smaller fishes may have been more tolerant of harsh environmental conditions than larger individuals of the same species. Differential mortalities among species and sizes during drawdowns in actively managed wetland pools may have intentional and unintentional ramifications on wetland and riverine fish community structure, fish-avian interactions, and implementing an ecosystem management perspective to restoring more naturalized river floodplain wetland functions. Late summer and early autumn draining of managed wetlands might be used to benefit a wider diversity of wildlife and fishes.

  16. A geomorphic framework to assess changes to aquatic habitat due to flow regulation and channel and floodplain alteration of the Cedar River, Washington

    NASA Astrophysics Data System (ADS)

    Gendaszek, A. S.; Magirl, C. S.; Barnas, C. R.; Konrad, C. P.; Little, R.

    2010-12-01

    Flow regulation, bank armoring, and floodplain alteration since the early 20th century have contributed to significant changes in the hydrologic regime and geomorphic processes of the Cedar River in Washington State. The Cedar River originates in the Cascade Range, provides drinking water to the Seattle metropolitan area, and supports several populations of anadromous salmonids. Flow regulation currently has limited influence on the magnitude, duration, and timing of high-flow events, which affect the incubation of salmonids as well as the production and maintenance of their habitat. Unlike structural changes to the channel and floodplain, flow regulation may be modified in the short-term to improve the viability of salmon populations. An understanding of the effects of flow regulation on those populations must be discerned over a range of scales from individual floods that affect the size of individual year classes to decadal high flow regime that influences the amount and quality of channel and off-channel habitat available for spawning and rearing. We present estimates of reach-scale sediment budgets and changes to channel morphology derived from historical orthoimagery, specific gage analyses at four long-term streamflow-gaging stations to quantify trends in aggradation, and hydrologic statistics of the magnitude and duration of peak streamflows. These data suggest a gradient of channel types from unconfined, sediment-rich segments to confined, sediment-poor segments that are likely to have distinct responses to high flows. Particle-size distribution data and longitudinal water surface and streambed profiles for the 56 km downstream of Chester Morse Lake measured in 2010 show the spatial extent of preferred salmonid habitat along the Cedar River. These historical and current data constitute a geomorphic framework to help assess different river management scenarios for salmonid habitat and population viability.

  17. Patterns of floodplain sediment deposition along the regulated lower Roanoke River, North Carolina: annual, decadal, centennial scales

    USGS Publications Warehouse

    Hupp, Cliff R.; Schenk, Edward R.; Kroes, Daniel; Willard, Debra A.; Townsend, Phil A.; Peet, Robert K.

    2015-01-01

    The lower Roanoke River on the Coastal Plain of North Carolina is not embayed and maintains a floodplain that is among the largest on the mid-Atlantic Coast. This floodplain has been impacted by substantial aggradation in response to upstream colonial and post-colonial agriculture between the mid-eighteenth and mid-nineteenth centuries. Additionally, since the mid-twentieth century stream flow has been regulated by a series of high dams. We used artificial markers (clay pads), tree-ring (dendrogeomorphic) techniques, and pollen analyses to document sedimentation rates/amounts over short-, intermediate-, and long-term temporal scales, respectively. These analyses occurred along 58 transects at 378 stations throughout the lower river floodplain from near the Fall Line to the Albemarle Sound. Present sediment deposition rates ranged from 0.5 to 3.4 mm/y and 0.3 to 5.9 mm/y from clay pad and dendrogeomorphic analyses, respectively. Deposition rates systematically increased from upstream (high banks and floodplain) to downstream (low banks) reaches, except the lowest reaches. Conversely, legacy sediment deposition (A.D. 1725 to 1850) ranged from 5 to about 40 mm/y, downstream to upstream, respectively, and is apparently responsible for high banks upstream and large/wide levees along some of the middle stream reaches. Dam operations have selectively reduced levee deposition while facilitating continued backswamp deposition. A GIS-based model predicts 453,000 Mg of sediment is trapped annually on the floodplain and that little watershed-derived sediment reaches the Albemarle Sound. Nearly all sediment in transport and deposited is derived from the channel bed and banks. Legacy deposits (sources) and regulated discharges affect most aspects of present fluvial sedimentation dynamics. The lower river reflects complex relaxation conditions following both major human alterations, yet continues to provide the ecosystem service of sediment trapping.

  18. Patterns of floodplain sediment deposition along the regulated lower Roanoke River, North Carolina: Annual, decadal, centennial scales

    NASA Astrophysics Data System (ADS)

    Hupp, C. R.; Schenk, E. R.; Kroes, D. E.; Willard, D. A.; Townsend, P. A.; Peet, R. K.

    2015-01-01

    The lower Roanoke River on the Coastal Plain of North Carolina is not embayed and maintains a floodplain that is among the largest on the mid-Atlantic Coast. This floodplain has been impacted by substantial aggradation in response to upstream colonial and post-colonial agriculture between the mid-eighteenth and mid-nineteenth centuries. Additionally, since the mid-twentieth century stream flow has been regulated by a series of high dams. We used artificial markers (clay pads), tree-ring (dendrogeomorphic) techniques, and pollen analyses to document sedimentation rates/amounts over short-, intermediate-, and long-term temporal scales, respectively. These analyses occurred along 58 transects at 378 stations throughout the lower river floodplain from near the Fall Line to the Albemarle Sound. Present sediment deposition rates ranged from 0.5 to 3.4 mm/y and 0.3 to 5.9 mm/y from clay pad and dendrogeomorphic analyses, respectively. Deposition rates systematically increased from upstream (high banks and floodplain) to downstream (low banks) reaches, except the lowest reaches. Conversely, legacy sediment deposition (A.D. 1725 to 1850) ranged from 5 to about 40 mm/y, downstream to upstream, respectively, and is apparently responsible for high banks upstream and large/wide levees along some of the middle stream reaches. Dam operations have selectively reduced levee deposition while facilitating continued backswamp deposition. A GIS-based model predicts 453,000 Mg of sediment is trapped annually on the floodplain and that little watershed-derived sediment reaches the Albemarle Sound. Nearly all sediment in transport and deposited is derived from the channel bed and banks. Legacy deposits (sources) and regulated discharges affect most aspects of present fluvial sedimentation dynamics. The lower river reflects complex relaxation conditions following both major human alterations, yet continues to provide the ecosystem service of sediment trapping.

  19. Sedimentation patterns in floodplains of the Mekong Delta - Vietnam

    NASA Astrophysics Data System (ADS)

    Van Manh, Nguyen; Merz, Bruno; Viet Dung, Nguyen; Apel, Heiko

    2013-04-01

    Quantification of floodplain sedimentation during the flood season in the Mekong Delta (MD) plays a very important role in the assessment of flood deposits for a sustainable agro-economic development. Recent studies on floodplain sedimentation in the region are restricted to small pilot sites because of the large extend of the Delta, and the complex channel. This research aims at a quantification of the sediment deposition in floodplains of the whole Mekong Delta, and to access the impacts of the upstream basin development on the sedimentation in the Delta quantitatively. To achieve this, a suspended sediment transport model is developed based on the quasi-2D hydrodynamic model of the whole Mekong Delta developed by Dung et al. (2011). The model is calibrated and validated using observed data derived from several sediment measurement campaigns in channel networks and floodplains. Measured sediment data and hydrodynamic model quantify the spatio-temporal variability of sediment depositions in different spatial units: individual dyke compartments, and the sub-regions Plain of Reeds, Long Xuyen Quadrangle and the area between Tien River and Hau River. It is shown that the distribution of sediment deposition over the delta is highly depended on the flood magnitude, that in turn drives the operation policy of flood control systems in floodplains of the Mekong Delta. Thus, the sedimentation distribution is influenced by the protection level of the dyke systems in place and the distance to the Tien River and Hau River, the main branches of the Mekong in the Delta. This corroborates the main findings derived from data analysis obtained from a small scale test site by Hung et al, (2011, 2012a). Moreover, the results obtained here underlines the importance of the main channels for the sediment transport into the floodplains, and the deposition rate in floodplains is strongly driven by the intake locations and the distance from these to the main channels as well.

  20. Agricultural conversion of floodplain ecosystems: implications for groundwater quality.

    PubMed

    Schilling, Keith E; Jacobson, Peter J; Vogelgesang, Jason A

    2015-04-15

    With current trends of converting grasslands to row crop agriculture in vulnerable areas, there is a critical need to evaluate the effects of land use on groundwater quality in large river floodplain systems. In this study, groundwater hydrology and nutrient dynamics associated with three land cover types (grassland, floodplain forest and cropland) were assessed at the Cedar River floodplain in southeastern Iowa. The cropland site consisted of newly-converted grassland, done specifically for our study. Our objectives were to evaluate spatial and temporal variations in groundwater hydrology and quality, and quantify changes in groundwater quality following land conversion from grassland to row crop in a floodplain. We installed five shallow and one deep monitoring wells in each of the three land cover types and recorded water levels and quality over a three year period. Crop rotations included soybeans in year 1, corn in year 2 and fallow with cover crops during year 3 due to river flooding. Water table levels behaved nearly identically among the sites but during the second and third years of our study, NO₃-N concentrations in shallow floodplain groundwater beneath the cropped site increased from 0.5 mg/l to more than 25 mg/l (maximum of 70 mg/l). The increase in concentration was primarily associated with application of liquid N during June of the second year (corn rotation), although site flooding may have exacerbated NO₃-N leaching. Geophysical investigation revealed differences in ground conductivity among the land cover sites that related significantly to variations in groundwater quality. Study results provide much-needed information on the effects of different land covers on floodplain groundwater and point to challenges ahead for meeting nutrient reduction goals if row crop land use expands into floodplains. PMID:25687808

  1. Agricultural conversion of floodplain ecosystems: implications for groundwater quality.

    PubMed

    Schilling, Keith E; Jacobson, Peter J; Vogelgesang, Jason A

    2015-04-15

    With current trends of converting grasslands to row crop agriculture in vulnerable areas, there is a critical need to evaluate the effects of land use on groundwater quality in large river floodplain systems. In this study, groundwater hydrology and nutrient dynamics associated with three land cover types (grassland, floodplain forest and cropland) were assessed at the Cedar River floodplain in southeastern Iowa. The cropland site consisted of newly-converted grassland, done specifically for our study. Our objectives were to evaluate spatial and temporal variations in groundwater hydrology and quality, and quantify changes in groundwater quality following land conversion from grassland to row crop in a floodplain. We installed five shallow and one deep monitoring wells in each of the three land cover types and recorded water levels and quality over a three year period. Crop rotations included soybeans in year 1, corn in year 2 and fallow with cover crops during year 3 due to river flooding. Water table levels behaved nearly identically among the sites but during the second and third years of our study, NO₃-N concentrations in shallow floodplain groundwater beneath the cropped site increased from 0.5 mg/l to more than 25 mg/l (maximum of 70 mg/l). The increase in concentration was primarily associated with application of liquid N during June of the second year (corn rotation), although site flooding may have exacerbated NO₃-N leaching. Geophysical investigation revealed differences in ground conductivity among the land cover sites that related significantly to variations in groundwater quality. Study results provide much-needed information on the effects of different land covers on floodplain groundwater and point to challenges ahead for meeting nutrient reduction goals if row crop land use expands into floodplains.

  2. Ecosystem structure, function, and composition in rangelands are negatively affected by livestock grazing.

    PubMed

    Eldridge, David J; Poore, Alistair G B; Ruiz-Colmenero, Marta; Letnic, Mike; Soliveres, Santiago

    2016-06-01

    Reports of positive or neutral effects of grazing on plant species richness have prompted calls for livestock grazing to be used as a tool for managing land for conservation. Grazing effects, however, are likely to vary among different response variables, types, and intensity of grazing, and across abiotic conditions. We aimed to examine how grazing affects ecosystem structure, function, and composition. We compiled a database of 7615 records reporting an effect of grazing by sheep and cattle on 278 biotic and abiotic response variables for published studies across Australia. Using these data, we derived three ecosystem measures based on structure, function, and composition, which were compared against six contrasts of grazing pressure, ranging from low to heavy, two different herbivores (sheep, cattle), and across three different climatic zones. Grazing reduced structure (by 35%), function (24%), and composition (10%). Structure and function (but not composition) declined more when grazed by sheep and cattle together than sheep alone. Grazing reduced plant biomass (40%), animal richness (15%), and plant and animal abundance, and plant and litter cover (25%), but had no effect on plant richness nor soil function. The negative effects of grazing on plant biomass, plant cover, and soil function were more pronounced in drier environments. Grazing effects on plant and animal richness and composition were constant, or even declined, with increasing aridity. Our study represents a comprehensive continental assessment of the implications of grazing for managing Australian rangelands. Grazing effects were largely negative, even at very low levels of grazing. Overall, our results suggest that livestock grazing in Australia is unlikely to produce positive outcomes for ecosystem structure, function, and composition or even as a blanket conservation tool unless reduction in specific response variables is an explicit management objective.

  3. Ecosystem structure, function, and composition in rangelands are negatively affected by livestock grazing.

    PubMed

    Eldridge, David J; Poore, Alistair G B; Ruiz-Colmenero, Marta; Letnic, Mike; Soliveres, Santiago

    2016-06-01

    Reports of positive or neutral effects of grazing on plant species richness have prompted calls for livestock grazing to be used as a tool for managing land for conservation. Grazing effects, however, are likely to vary among different response variables, types, and intensity of grazing, and across abiotic conditions. We aimed to examine how grazing affects ecosystem structure, function, and composition. We compiled a database of 7615 records reporting an effect of grazing by sheep and cattle on 278 biotic and abiotic response variables for published studies across Australia. Using these data, we derived three ecosystem measures based on structure, function, and composition, which were compared against six contrasts of grazing pressure, ranging from low to heavy, two different herbivores (sheep, cattle), and across three different climatic zones. Grazing reduced structure (by 35%), function (24%), and composition (10%). Structure and function (but not composition) declined more when grazed by sheep and cattle together than sheep alone. Grazing reduced plant biomass (40%), animal richness (15%), and plant and animal abundance, and plant and litter cover (25%), but had no effect on plant richness nor soil function. The negative effects of grazing on plant biomass, plant cover, and soil function were more pronounced in drier environments. Grazing effects on plant and animal richness and composition were constant, or even declined, with increasing aridity. Our study represents a comprehensive continental assessment of the implications of grazing for managing Australian rangelands. Grazing effects were largely negative, even at very low levels of grazing. Overall, our results suggest that livestock grazing in Australia is unlikely to produce positive outcomes for ecosystem structure, function, and composition or even as a blanket conservation tool unless reduction in specific response variables is an explicit management objective. PMID:27509764

  4. Numerical Model for Channel/Floodplain Exchange on a Gravel Bed River: Relative Importance of Upstream and Downstream Boundaries and of Lateral Exchange (Invited)

    NASA Astrophysics Data System (ADS)

    Lauer, J. W.

    2013-12-01

    The centennial-scale evolution of a meandering gravel-bed river has been represented using a size-specific 1-D sediment transport model. The model differs from other 1-D morphodynamic models for gravel-bed rivers in that it allows for sediment storage in and remobilization from an off-channel sediment storage reservoir representing the floodplain. Hydraulics is represented using a 1-D gradually varied flow model that assumes a rectangular cross-section for the channel zone and a constant elevation for the floodplain. Because the solution for steady uniform flow is necessarily iterative in this framework, the gradually varied hydraulic model is not significantly more computationally intensive than is a normal flow solution. The model is parameterized primarily based on the assumption that the channel creates point bars at a constant elevation above the bed. Bar progradation rate is assumed equal to a specified lateral migration rate (which can vary as a function of sediment load). The return of sediment from floodplain to channel is assumed equal to the lateral migration rate times the average bank elevation. Any net imbalance in sediment storage within the floodplain zone results in a change in average elevation and size distribution for the floodplain. This in turn affects the partition of flow between channel and floodplain and the net flux of sediment from the floodplain to channel, eventually causing the model to evolve toward a steady state bankfull capacity. The model is applied to the Ain River, France, a tributary of the Rhône River. The Ain River underwent significant geomorphic transformations over the course of the 20th century in response to changes in climate, vegetation, floodplain management, and, especially, because of the installation of a series of hydroelectric dams. In general, the channel became more incised and less laterally active during this period. However, bank erosion and sediment deposition in bars and floodplain channels continues to

  5. Seasonal Variations in Subsurface Electrical Resistivity in a Floodplain Aquifer

    NASA Astrophysics Data System (ADS)

    Esker, A.; Marshall, S. T.

    2015-12-01

    In an attempt to create a three-dimensional model of a floodplain aquifer along the New River in western North Carolina, we have collected numerous DC electrical resistivity profiles over the course of six years. Unfortunately, the electrical resistivity of geologic materials can be partially controlled by temperature and water content which both vary temporally. To determine the extent to which resistivity data is affected by temporal variations at our site, we conducted multiple DC electrical resistivity surveys collected at the same location at various times of the year to quantify changes in the resistivity patterns. We use a Wenner array that offers a large signal to noise ratio, but relatively few data points, and a Dipole-Dipole array that produces more data, but is more sensitive to noise. For each data acquisition date, we measure the depth to water at seven boreholes parallel to the survey to determine if any of the collected resistivity surveys can be independently used to detect the water table and if any changes affect subsurface resistivities. We created a stacked model of all surveys of the same array type, and compare to each survey to qualitatively and quantitatively identify changes in the subsurface patterns. Results indicate there are few major changes in the qualitative subsurface patterns with time. RMS errors between the stacked model and different surveys range from 56 to 201 Ohm-m and percent differences range from 5.84% to 21.50%. The surveys with largest RMS errors correspond to days that had a significant change of water table level from the static level. Our preliminary results suggest that so long as surveys are collected during similar water table conditions, data from multiple years should yield similar results. Furthermore, the subsurface resistivity values and GPR surveys do not clearly delineate the water table levels, suggesting that near surface geophysical methods many not be able to detect the water table at our site.

  6. Environmental variables measured at multiple spatial scales exert uneven influence on fish assemblages of floodplain lakes

    USGS Publications Warehouse

    Dembkowski, Daniel J.; Miranda, Leandro E.

    2014-01-01

    We examined the interaction between environmental variables measured at three different scales (i.e., landscape, lake, and in-lake) and fish assemblage descriptors across a range of over 50 floodplain lakes in the Mississippi Alluvial Valley of Mississippi and Arkansas. Our goal was to identify important local- and landscape-level determinants of fish assemblage structure. Relationships between fish assemblage structure and variables measured at broader scales (i.e., landscape-level and lake-level) were hypothesized to be stronger than relationships with variables measured at finer scales (i.e., in-lake variables). Results suggest that fish assemblage structure in floodplain lakes was influenced by variables operating on three different scales. However, and contrary to expectations, canonical correlations between in-lake environmental characteristics and fish assemblage structure were generally stronger than correlations between landscape-level and lake-level variables and fish assemblage structure, suggesting a hierarchy of influence. From a resource management perspective, our study suggests that landscape-level and lake-level variables may be manipulated for conservation or restoration purposes, and in-lake variables and fish assemblage structure may be used to monitor the success of such efforts.

  7. Cognitive structure and the affective domain: on knowing and feeling in biology

    NASA Astrophysics Data System (ADS)

    Thompson, Tressa L.; Mintzes, Joel J.

    2002-06-01

    This cross-age study explored the structural complexity and propositional validity of knowledge about and attitudes toward sharks, and the relationships among knowledge and attitudes. Responses were elicited from a convenience sample of students (5th, 8th and 11th grade, and college level) and senior citizens (n = 238). All subjects constructed a concept map on sharks and responded to a Likert-type attitude inventory. Based on the work of Novak and Gowin (Leaning How to Learn, Cambridge University Press, 1984), concept maps were scored for frequencies of non-redundant concepts and scientifically valid relationships, levels of hierarchy, incidence of branching and number of crosslinks. The attitude inventory, emerging from Kellert's (The Value of Life: Biological Diversity and Human Society, Island Press, 1996) work, generated subscale scores on four affective dimensions: scientific, naturalistic, moralistic and utilitarian/negative. Significant differences were found among subject groups on all knowledge structure variables and attitudinal dimensions. Gender differences were documented on three of four attitude subscales. A series of simple, mulitiple and canonical correlations revealed moderately strong relationships between knowledge structure variables and attitudinal dimensions. The pattern of these relationships supports conservation education efforts and instructional practices that encourage meaningful learning, knowledge restructuring and conceptual change (Mintzes et al., Assessing Science Understanding: A Human Constructivist View, Academic Press, 2000).

  8. The constant region affects antigen binding of antibodies to DNA by altering secondary structure.

    PubMed

    Xia, Yumin; Janda, Alena; Eryilmaz, Ertan; Casadevall, Arturo; Putterman, Chaim

    2013-11-01

    We previously demonstrated an important role of the constant region in the pathogenicity of anti-DNA antibodies. To determine the mechanisms by which the constant region affects autoantibody binding, a panel of isotype-switch variants (IgG1, IgG2a, IgG2b) was generated from the murine PL9-11 IgG3 autoantibody. The affinity of the PL9-11 antibody panel for histone was measured by surface plasmon resonance (SPR). Tryptophan fluorescence was used to determine wavelength shifts of the antibody panel upon binding to DNA and histone. Finally, circular dichroism spectroscopy was used to measure changes in secondary structure. SPR analysis revealed significant differences in histone binding affinity between members of the PL9-11 panel. The wavelength shifts of tryptophan fluorescence emission were found to be dependent on the antibody isotype, while circular dichroism analysis determined that changes in antibody secondary structure content differed between isotypes upon antigen binding. Thus, the antigen binding affinity is dependent on the particular constant region expressed. Moreover, the effects of antibody binding to antigen were also constant region dependent. Alteration of secondary structures influenced by constant regions may explain differences in fine specificity of anti-DNA antibodies between antibodies with similar variable regions, as well as cross-reactivity of anti-DNA antibodies with non-DNA antigens.

  9. Structural diversity of organochlorine compounds in groundwater affected by an industrial point source.

    PubMed

    Frische, Kerstin; Schwarzbauer, Jan; Ricking, Mathias

    2010-09-01

    Groundwater samples contaminated by an industrial point source were analysed in order to reveal the structural diversity of halogenated organic contaminants. Particular focus was laid on the metabolites and derivatives related to the pesticides DDT (2,2-bis(chlorophenyl)-1,1,1-trichlorethane) and lindane (γ-hexachlorocyclohexane). Additionally, a wide range of chlorinated and brominated xenobiotics were identified. These results represent a high degree of contamination with organochlorine compounds illustrating a considerable structural diversity in groundwater in the vicinity of the industrial plant. The polar DDT-metabolite DDA (2,2-bis(chlorophenyl)acetic acid), which has been neglected in water studies widely, represents the main DDT metabolite analysed in the water samples. Besides DDA, some unknown substances with structural relation to DDA and DDT were detected and identified, in detail 2,2-bis(4-chlorophenyl)acetic acid N-methyl amide (DDAMA) and 2,2-bis(4-chlorophenyl)acetic acid n-butyl ester (DDABE). As an overall implication of this study it has to be demanded that analysis of industrially affected ground waters have to be based on screening analysis for a comprehensive view on the state of pollution.

  10. Vancomycin and maltodextrin affect structure and activity of Staphylococcus aureus biofilms.

    PubMed

    Kiamco, Mia Mae; Atci, Erhan; Khan, Qaiser Farid; Mohamed, Abdelrhman; Renslow, Ryan S; Abu-Lail, Nehal; Fransson, Boel A; Call, Douglas R; Beyenal, Haluk

    2015-12-01

    Hyperosmotic agents such as maltodextrin negatively impact bacterial growth through osmotic stress without contributing to drug resistance. We hypothesized that a combination of maltodextrin (osmotic agent) and vancomycin (antibiotic) would be more effective against Staphylococcus aureus biofilms than either alone. To test our hypothesis, S. aureus was grown in a flat plate flow cell reactor. Confocal laser scanning microscopy images were analyzed to quantify changes in biofilm structure. We used dissolved oxygen microelectrodes to quantify how vancomycin and maltodextrin affected the respiration rate and oxygen penetration into the biofilm. We found that treatment with vancomycin or maltodextrin altered biofilm structure. The effect on the structure was significant when they were used simultaneously to treat S. aureus biofilms. In addition, vancomycin treatment increased the oxygen respiration rate, while maltodextrin treatment caused an increase and then a decrease. An increased maltodextrin concentration decreased the diffusivity of the antibiotic. Overall, we conclude that (1) an increased maltodextrin concentration decreases vancomycin diffusion but increases the osmotic effect, leading to the optimum treatment condition, and (2) the combination of vancomycin and maltodextrin is more effective against S. aureus biofilms than either alone. Vancomycin and maltodextrin act together to increase the effectiveness of treatment against S. aureus biofilm growth.

  11. Forest Structure Affects Soil Mercury Losses in the Presence and Absence of Wildfire.

    PubMed

    Homann, Peter S; Darbyshire, Robyn L; Bormann, Bernard T; Morrissette, Brett A

    2015-11-01

    Soil is an important, dynamic component of regional and global mercury (Hg) cycles. This study evaluated how changes in forest soil Hg masses caused by atmospheric deposition and wildfire are affected by forest structure. Pre and postfire soil Hg measurements were made over two decades on replicate experimental units of three prefire forest structures (mature unthinned, mature thinned, clear-cut) in Douglas-fir dominated forest of southwestern Oregon. In the absence of wildfire, O-horizon Hg decreased by 60% during the 14 years after clearcutting, possibly the result of decreased atmospheric deposition due to the smaller-stature vegetative canopy; in contrast, no change was observed in mature unthinned and thinned forest. Wildfire decreased O-horizon Hg by >88% across all forest structures and decreased mineral-soil (0 to 66 mm depth) Hg by 50% in thinned forest and clear-cut. The wildfire-associated soil Hg loss was positively related to the amount of surface fine wood that burned during the fire, the proportion of area that burned at >700 °C, fire severity as indicated by tree mortality, and soil C loss. Loss of soil Hg due to the 200,000 ha wildfire was more than four times the annual atmospheric Hg emissions from human activities in Oregon.

  12. DHPC strongly affects the structure and oligomerization propensity of Alzheimer's Aβ(1-40) peptide.

    PubMed

    Dahse, Kirsten; Garvey, Megan; Kovermann, Michael; Vogel, Alexander; Balbach, Jochen; Fändrich, Marcus; Fahr, Alfred

    2010-11-01

    Alzheimer's disease (AD) is thought to depend on the deleterious action of amyloid fibrils or oligomers derived from β-amyloid (Aβ) peptide. Out of various known Aβ alloforms, the 40-residue peptide Aβ(1-40) occurs at highest concentrations inside the brains of AD patients. Its aggregation properties critically depend on lipids, and it was thus proposed that lipids could play a major role in AD. To better understand their possible effects on the structure of Aβ and on the ability of this peptide to form potentially detrimental amyloid structures, we here analyze the interactions between Aβ(1-40) and 1,2-dihexanoyl-sn-glycero-3-phosphocholine (DHPC). DHPC has served, due to its controlled properties, as a major model system for studying general lipid properties. Here, we show that DHPC concentrations of 8 mM or higher exert dramatic effects on the conformation of soluble Aβ(1-40) peptide and induce the formation of β-sheet structure at high levels. By contrast, we find that DHPC concentrations well below the critical micelle concentration present no discernible effect on the conformation of soluble Aβ, although they substantially affect the peptide's oligomerization and fibrillation kinetics. These data imply that subtle lipid-peptide interactions suffice in controlling the overall aggregation properties and drastically accelerate, or delay, the fibrillation kinetics of Aβ peptide in near-physiological buffer solutions.

  13. Herbivore species richness and feeding complementarity affect community structure and function on a coral reef

    PubMed Central

    Burkepile, Deron E.; Hay, Mark E.

    2008-01-01

    Consumer effects on prey are well known for cascading through food webs and producing dramatic top-down effects on community structure and ecosystem function. Bottom-up effects of prey (primary producer) biodiversity are also well known. However, the role of consumer diversity in affecting community structure or ecosystem function is not well understood. Here, we show that herbivore species richness can be critical for maintaining the structure and function of coral reefs. In two experiments over 2 years, we constructed large cages enclosing single herbivore species, equal densities of mixed species of herbivores, or excluding herbivores and assessed effects on both seaweeds and corals. When compared with single-herbivore treatments, mixed-herbivore treatments lowered macroalgal abundance by 54–76%, enhanced cover of crustose coralline algae (preferred recruitment sites for corals) by 52–64%, increased coral cover by 22%, and prevented coral mortality. Complementary feeding by herbivorous fishes drove the herbivore richness effects, because macroalgae were unable to effectively deter fishes with different feeding strategies. Maintaining herbivore species richness appears critical for preserving coral reefs, because complementary feeding by diverse herbivores produces positive, but indirect, effects on corals, the foundation species for the ecosystem. PMID:18845686

  14. Floodplains and Sedimentation Processes in a Changing Basin: Case Study Sacramento Valley

    NASA Astrophysics Data System (ADS)

    Singer, M. B.; Aalto, R.

    2006-12-01

    The diverse floodplains of the Sacramento Valley in California have undergone dramatic post-glaciation changes. The natural reduction in sediment supply following glacial melting appears to have altered channel pattern of the in the Middle Sacramento River from braided to meandering. This trend has been exacerbated by recent dam construction, gravel and sand mining, and bank protection, which have apparently increased the frequency of chute cutoff and decreased channel sinuosity. The sum of factors controlling sediment supply and channel pattern are evidently converting the Sacramento from an aggraded river with frequent access to its natural floodplain to a degrading river with limited connectivity. We have documented via 210Pb dating low volumes of recent sediment transfer to: inset floodplains in Upper Sacramento River canyons; meander belt deposits, low-lying sinks bounding natural levees, and oxbow lakes along the Middle Sacramento River; and crevasses splay deposits and lowland floodways in the Lower Sacramento Valley. These observations are contrasted with historical maps and preserved deposits from the previous era of floodplain creation, which suggest higher rates of sediment accumulation. The presence of high sand content in recent deposits along channel margins determined via granulometry and its rapid decline with depth and distance from the channel attests to recent erosion of channel sediments throughout the Sacramento River. Most of the natural crevasses splays that once dominated sediment transfer into floodplains along the Sacramento's lower course have been cut off from the channel by flood control levees built upon channel banks. However, several splay fans were retrofitted for use in the valley's flood control system (c. 1920's) as lateral spill weirs that shunt flood flow out of the mainstem Sacramento River. These weirs focus flow and sediment transport into engineered floodways (i.e., leveed portions of natural low gradient flood basins

  15. Hydroecological factors governing surface water flow on a low-gradient floodplain

    NASA Astrophysics Data System (ADS)

    Harvey, Judson W.; Schaffranek, Raymond W.; Noe, Gregory B.; Larsen, Laurel G.; Nowacki, Daniel J.; O'Connor, Ben L.

    2009-03-01

    Interrelationships between hydrology and aquatic ecosystems are better understood in streams and rivers compared to their surrounding floodplains. Our goal was to characterize the hydrology of the Everglades ridge and slough floodplain ecosystem, which is valued for the comparatively high biodiversity and connectivity of its parallel-drainage features but which has been degraded over the past century in response to flow reductions associated with flood control. We measured flow velocity, water depth, and wind velocity continuously for 3 years in an area of the Everglades with well-preserved parallel-drainage features (i.e., 200-m wide sloughs interspersed with slightly higher elevation and more densely vegetated ridges). Mean daily flow velocity averaged 0.32 cm s-1 and ranged between 0.02 and 0.79 cm s-1. Highest sustained velocities were associated with flow pulses caused by water releases from upstream hydraulic control structures that increased flow velocity by a factor of 2-3 on the floodplain for weeks at a time. The highest instantaneous measurements of flow velocity were associated with the passage of Hurricane Wilma in 2005 when the inverse barometric pressure effect increased flow velocity up to 5 cm s-1 for several hours. Time-averaged flow velocities were 29% greater in sloughs compared to ridges because of marginally higher vegetative drag in ridges compared to sloughs, which contributed modestly (relative to greater water depth and flow duration in sloughs compared to ridges) to the predominant fraction (86%) of total discharge through the landscape occurring in sloughs. Univariate scaling relationships developed from theory of flow through vegetation, and our field data indicated that flow velocity increases with the square of water surface slope and the fourth power of stem diameter, decreases in direct proportion with increasing frontal area of vegetation, and is unrelated to water depth except for the influence that water depth has in controlling

  16. Hydroecological factors governing surface water flow on a low-gradient floodplain

    USGS Publications Warehouse

    Harvey, J.W.; Schaffranek, R.W.; Noe, G.B.; Larsen, L.G.; Nowacki, D.J.; O'Connor, B.L.

    2009-01-01

    Interrelationships between hydrology and aquatic ecosystems are better understood in streams and rivers compared to their surrounding floodplains. Our goal was to characterize the hydrology of the Everglades ridge and slough floodplain ecosystem, which is valued for the comparatively high biodiversity and connectivity of its parallel-drainage features but which has been degraded over the past century in response to flow reductions associated with flood control. We measured flow velocity, water depth, and wind velocity continuously for 3 years in an area of the Everglades with well-preserved parallel-drainage features (i.e., 200-m wide sloughs interspersed with slightly higher elevation and more densely vegetated ridges). Mean daily flow velocity averaged 0.32 cm s-1 and ranged between 0.02 and 0.79 cm s-1. Highest sustained velocities were associated with flow pulses caused by water releases from upstream hydraulic control structures that increased flow velocity by a factor of 2-3 on the floodplain for weeks at a time. The highest instantaneous measurements of flow velocity were associated with the passage of Hurricane Wilma in 2005 when the inverse barometric pressure effect increased flow velocity up to 5 cm s-1 for several hours. Time-averaged flow velocities were 29% greater in sloughs compared to ridges because of marginally higher vegetative drag in ridges compared to sloughs, which contributed modestly (relative to greater water depth and flow duration in sloughs compared to ridges) to the predominant fraction (86%) of total discharge through the landscape occurring in sloughs. Univariate scaling relationships developed from theory of flow through vegetation, and our field data indicated that flow velocity increases with the square of water surface slope and the fourth power of stem diameter, decreases in direct proportion with increasing frontal area of vegetation, and is unrelated to water depth except for the influence that water depth has in controlling

  17. Understanding the value of local ecological knowledge and practices for habitat restoration in human-altered floodplain systems: a case from Bangladesh.

    PubMed

    Mamun, Abdullah-Al

    2010-05-01

    Worldwide there is a declining trend in natural fish catch (FAO, The state of world fisheries and aquaculture. http://www.fao.org/documents/show_cdr.asp?url_file=/docrep/007/y5600e/y5600e00.htm , 2002) and Bangladesh is no exception. The vast inland fisheries of Bangladesh have been declining over the years, largely a result of human alteration of the aquatic habitats arising from human interventions in the floodplain systems such as the establishment of water control structures which favor agricultural production but reduce fish habitats. It can be assumed that conventional management measures are not adequate to conserve natural fisheries and exploring alternative knowledge systems to complement existing management is warranted. This paper focuses on local ecological knowledge and several other local practices held by fishers engaging directly with floodplain ecosystems. These knowledge systems and practices may be valuable tools for understanding ecosystems processes and related changes and developing local level responses to avert negative consequences of such changes. This may help in devising alternatives to ecosystem management and the conservation of floodplain fish habitats of Bangladesh and elsewhere in the world. This study was conducted in a natural depression (locally called beel) and its surrounding floodplain system located in north central Bangladesh which has become highly degraded. The results of the study indicate that the fishers and local users of the floodplain ecosystems are rich in local ecological knowledge concerning the hydrology of the floodplains and small lakes, the habitat preferences of fish, the role of agricultural crops on fish habitats, and the impact of habitat human interventions in aquatic ecosystems. Given the apparent inadequacy of the present management regime, this article argues for an inclusion of local knowledge and practices into habitat management as a more holistic approach to floodplain habitat restoration and

  18. Social structure of lions (Panthera leo) is affected by management in Pendjari Biosphere Reserve, Benin.

    PubMed

    Sogbohossou, Etotépé A; Bauer, Hans; Loveridge, Andrew; Funston, Paul J; De Snoo, Geert R; Sinsin, Brice; De Iongh, Hans H

    2014-01-01

    Lion populations have undergone a severe decline in West Africa. As baseline for conservation management, we assessed the group structure of lions in the Pendjari Biosphere Reserve in Benin. This reserve, composed of one National Park and two Hunting Zones, is part of the WAP transboundary complex of protected areas. Overall mean group size was 2.6±1.7 individuals (n = 296), it was significantly higher in the National Park (2.7±1.7, n = 168) than in the Hunting Zones (2.2±1.5, n = 128). Overall adult sex ratio was even, but significantly biased towards females (0.67) in the National Park and towards males (1.67) in the Hunting Zones. Our results suggest that the Pendjari lion population is affected by perturbations, such as trophy hunting.

  19. The modern face of prejudice and structural features that moderate the effect of cooperation on affect.

    PubMed

    Vanman, E J; Paul, B Y; Ito, T A; Miller, N

    1997-11-01

    Facial muscle activity and self-reports were examined for racial bias in 3 studies. In the first 2 experiments, While participants imagined cooperating with a Black or White partner. Experiment 1 manipulated reward structure in the context of cooperating with a deficient partner. Experiment 2 manipulated partner deficiency and willingness to expend compensatory effort. On both facial EMG and self-report measures, joint rewards produced more negative affect than independent rewards. However, all partners were liked more when they were willing to try to compensate for their deficits. In addition, more liking was reported for Black partners, but EMG activity indicated bias against Blacks. Experiment 3 investigated individual differences in prejudice. Again, a greater preference for Blacks than Whites occurred on self-report measures, but in their facial muscle activity, high-prejudiced participants exhibited bias against Blacks. PMID:9364754

  20. Plant hybrid zones affect biodiversity: Tools for a genetic-based understanding of community structure

    SciTech Connect

    Whitham, T.G.; Martinsen, G.D.; Keim, P.; Floate, K.D.; Dungey, H.S. |; Potts, B.M.

    1999-03-01

    Plant hybrid zones are dynamic centers of ecological and evolutionary processes for plants and their associated communities. Studies in the wild and in gardens with synthetic crosses showed that hybrid eucalypts supports the greatest species richness and abundances of insect and fungal taxa. In an updated review of 152 case studies of taxa associated with diverse hybridizing systems, there were 43 (28%) cases of hybrids being more susceptible than their parent species, 7 (5%) resistant, 35 (23%) additive, 35 (23%) dominant, and 32 (21%) showed no response to hybridization. Thus, most taxa respond to hybrids in ways that result in equal or greater abundance, and hybrids tend to accumulate the taxa of their parent species. These studies suggest that genetic-based plant traits affect the distribution of many species and that the variation in hybrids can be used as tools to examine the genetic components of community structure and biodiversity.

  1. Spatial and spatiotemporal variation in metapopulation structure affects population dynamics in a passively dispersing arthropod.

    PubMed

    De Roissart, Annelies; Wang, Shaopeng; Bonte, Dries

    2015-11-01

    The spatial and temporal variation in the availability of suitable habitat within metapopulations determines colonization-extinction events, regulates local population sizes and eventually affects local population and metapopulation stability. Insights into the impact of such a spatiotemporal variation on the local population and metapopulation dynamics are principally derived from classical metapopulation theory and have not been experimentally validated. By manipulating spatial structure in artificial metapopulations of the spider mite Tetranychus urticae, we test to which degree spatial (mainland-island metapopulations) and spatiotemporal variation (classical metapopulations) in habitat availability affects the dynamics of the metapopulations relative to systems where habitat is constantly available in time and space (patchy metapopulations). Our experiment demonstrates that (i) spatial variation in habitat availability decreases variance in metapopulation size and decreases density-dependent dispersal at the metapopulation level, while (ii) spatiotemporal variation in habitat availability increases patch extinction rates, decreases local population and metapopulation sizes and decreases density dependence in population growth rates. We found dispersal to be negatively density dependent and overall low in the spatial variable mainland-island metapopulation. This demographic variation subsequently impacts local and regional population dynamics and determines patterns of metapopulation stability. Both local and metapopulation-level variabilities are minimized in mainland-island metapopulations relative to classical and patchy ones.

  2. Structural study of skeletal muscle fibres in healthy and pseudomyotonia affected cattle.

    PubMed

    Mascarello, Francesco; Sacchetto, Roberta

    2016-09-01

    Cattle congenital pseudomyotonia (PMT), recognized as naturally occurring animal model of human Brody disease, is an inherited recessive autosomal muscular disorder due to missense mutations in ATP2A1 gene, encoding sarco(endo)plasmic reticulum Ca(2+)-ATPase protein, isoform 1 (SERCA1). PMT has been described in the Chianina and Romagnola italian cattle breeds and as a single case in Dutch improved Red and White cross-breed. The genetic defect turned out to be heterogeneous in different cattle breeds, even though clinical symptoms were homogeneous. Skeletal muscles of affected animals are characterized by a selective deficiency of SERCA1 in sarcoplasmic reticulum (SR) membranes. Recently, we provided evidence that in Chianina breed, the ubiquitin proteasome system is responsible for SERCA1 mutant premature disposal, even when the mutation does not affect the catalytic properties of the pump. Results presented here show that all SERCA1 mutants described until now, although expressed at low level, are correctly targeted to SR membranes. Ultrastructural studies confirm that in pathological muscle fibres, structure, as well as triads, is well preserved. All together these results suggest that a possible therapeutical approach based on the rescue of the defective protein at SR membranes could be hypothesized. Only fully functionally active missense mutants, whem located at the SR membrane could restore the efficient control of Ca(2+) homeostasis and prevent the appearance of the pathological signs. Moreover, these data demonstrate the increasing importance of domestic animals as genetic models of human pathologies. PMID:27210062

  3. Spatial and spatiotemporal variation in metapopulation structure affects population dynamics in a passively dispersing arthropod.

    PubMed

    De Roissart, Annelies; Wang, Shaopeng; Bonte, Dries

    2015-11-01

    The spatial and temporal variation in the availability of suitable habitat within metapopulations determines colonization-extinction events, regulates local population sizes and eventually affects local population and metapopulation stability. Insights into the impact of such a spatiotemporal variation on the local population and metapopulation dynamics are principally derived from classical metapopulation theory and have not been experimentally validated. By manipulating spatial structure in artificial metapopulations of the spider mite Tetranychus urticae, we test to which degree spatial (mainland-island metapopulations) and spatiotemporal variation (classical metapopulations) in habitat availability affects the dynamics of the metapopulations relative to systems where habitat is constantly available in time and space (patchy metapopulations). Our experiment demonstrates that (i) spatial variation in habitat availability decreases variance in metapopulation size and decreases density-dependent dispersal at the metapopulation level, while (ii) spatiotemporal variation in habitat availability increases patch extinction rates, decreases local population and metapopulation sizes and decreases density dependence in population growth rates. We found dispersal to be negatively density dependent and overall low in the spatial variable mainland-island metapopulation. This demographic variation subsequently impacts local and regional population dynamics and determines patterns of metapopulation stability. Both local and metapopulation-level variabilities are minimized in mainland-island metapopulations relative to classical and patchy ones. PMID:25988264

  4. Brain network analysis reveals affected connectome structure in bipolar I disorder.

    PubMed

    Collin, Guusje; van den Heuvel, Martijn P; Abramovic, Lucija; Vreeker, Annabel; de Reus, Marcel A; van Haren, Neeltje E M; Boks, Marco P M; Ophoff, Roel A; Kahn, René S

    2016-01-01

    The notion that healthy brain function emerges from coordinated neural activity constrained by the brain's network of anatomical connections--i.e., the connectome--suggests that alterations in the connectome's wiring pattern may underlie brain disorders. Corroborating this hypothesis, studies in schizophrenia are indicative of altered connectome architecture including reduced communication efficiency, disruptions of central brain hubs, and affected "rich club" organization. Whether similar deficits are present in bipolar disorder is currently unknown. This study examines structural connectome topology in 216 bipolar I disorder patients as compared to 144 healthy controls, focusing in particular on central regions (i.e., brain hubs) and connections (i.e., rich club connections, interhemispheric connections) of the brain's network. We find that bipolar I disorder patients exhibit reduced global efficiency (-4.4%, P =0.002) and that this deficit relates (r = 0.56, P < 0.001) to reduced connectivity strength of interhemispheric connections (-13.0%, P = 0.001). Bipolar disorder patients were found not to show predominant alterations in the strength of brain hub connections in general, or of connections spanning brain hubs (i.e., "rich club" connections) in particular (all P > 0.1). These findings highlight a role for aberrant brain network architecture in bipolar I disorder with reduced global efficiency in association with disruptions in interhemispheric connectivity, while the central "rich club" system appears not to be particularly affected.

  5. Affect, Behavior, Cognition, and Desire in the Big Five: An Analysis of Item Content and Structure

    PubMed Central

    Wilt, Joshua; Revelle, William

    2015-01-01

    Personality psychology is concerned with affect (A), behavior (B), cognition (C) and desire (D), and personality traits have been defined conceptually as abstractions used to either explain or summarize coherent ABC (and sometimes D) patterns over time and space. However, this conceptual definition of traits has not been reflected in their operationalization, possibly resulting in theoretical and practical limitations to current trait inventories. Thus, the goal of this project was to determine the affective, behavioral, cognitive and desire (ABCD) components of Big-Five personality traits. The first study assessed the ABCD content of items measuring Big-Five traits in order to determine the ABCD composition of traits and identify items measuring relatively high amounts of only one ABCD content. The second study examined the correlational structure of scales constructed from items assessing ABCD content via a large, web-based study. An assessment of Big-Five traits that delineates ABCD components of each trait is presented, and the discussion focuses on how this assessment builds upon current approaches of assessing personality. PMID:26279606

  6. Revegetation standards for floodplain forest ecosystems in western Washington, USA

    SciTech Connect

    Zamora, B.

    1996-12-31

    Mining activity within floodplain landforms of western Washington, USA, presents unique problems in terms of approaches to revegetation and the success standards to be use to quantitatively evaluate revegetation success. Persistent historical disturbance of floodplain areas of the region has left little undisturbed natural vegetation to use as reference sites for development of success standards. A strategy is proposed for use of an ecological model of succession within floodplain vegetation to both identify revegetation options and provide a quantifiable and ecologically dynamic framework of success standards for revegetation evaluation. The floodplain forest moasic of mined lands in western Washington is a combination of (1) aquatic sites of open surface, impounded or flowing waters, (2) minerotrophic wetlands, and (3) xeroriparian sites between wetlands and uplands. Seven distinct and persistent plant communities of three community types are present are common. These physiognomic groupings successionally linked as habitats change from one flooding regime to another. Remenant stands of floodplain vegetation were used to construct a successional model which will provide for revegetation guidelines and a framework of success standards.

  7. Does body size affect a bird's sensitivity to patch size and landscape structure?

    USGS Publications Warehouse

    Winter, M.; Johnson, D.H.; Shaffer, J.A.

    2006-01-01

    Larger birds are generally more strongly affected by habitat loss and fragmentation than are smaller ones because they require more resources and thus larger habitat patches. Consequently, conservation actions often favor the creation or protection of larger over smaller patches. However, in grassland systems the boundaries between a patch and the surrounding landscape, and thus the perceived size of a patch, can be indistinct. We investigated whether eight grassland bird species with different body sizes perceived variation in patch size and landscape structure in a consistent manner. Data were collected from surveys conducted in 44 patches of northern tallgrass prairie during 1998-2001. The response to patch size was very similar among species regardless of body size (density was little affected by patch size), except in the Greater Prairie-Chicken (Tympanuchus cupido), which showed a threshold effect and was not found in patches smaller than 140 ha. In landscapes containing 0%-30% woody vegetation, smaller species responded more negatively to increases in the percentage of woody vegetation than larger species, but above an apparent threshold of 30%, larger species were not detected. Further analyses revealed that the observed variation in responses to patch size and landscape structure among species was not solely due to body size per se, but to other differences among species. These results indicate that a stringent application of concepts requiring larger habitat patches for larger species appears to limit the number of grassland habitats that can be protected and may not always be the most effective conservation strategy. ?? The Cooper Ornithological Society 2006.

  8. Low Elevation Old Channel Features of the Willamette River Floodplain Support High Subsurface Denitrification Rates

    EPA Science Inventory

    Background/Question/Methods: Large river floodplains are poor nitrate pollution buffers when polluted groundwater moves beneath biogeochemically retentive zones prior to entering the main channel. However, in floodplain regions with extensive backwaters and organic carbon acc...

  9. Low elevation inland habitats of the Willamette River floodplain support enhanced denitrification

    EPA Science Inventory

    Floodplain nitrate removal via denitrification in sediment provides an important ecosystem service that may be a valuable sink for nitrate pollution. At this time, much floodplain restoration is taking place with little consideration for in-situ nutrient processing, necessitating...

  10. Plains cottonwood's last stand: can it survive invasion of Russian olive onto the Milk River, Montana floodplain?

    PubMed

    Pearce, C M; Smith, D G

    2001-11-01

    Russian olive (Elaeagnus angustifolia L.) was introduced in 1950 onto one site on the Milk River floodplain, northern Montana, 10 km downstream from the Canada/United States border. To analyze dispersal of Russian olive from the point source between 1950 and 1999, we compared distribution, numbers, size structure, and mortality of Russian olive and plains cottonwood (Populus deltoides Marsh:) on an unregulated reach of the Milk River floodplain in southeastern Alberta and north-central Montana. Within 50 years, Russian olive in this reach has moved upriver into Alberta and downriver to the Fresno Reservoir. It is now present on 69 of the 74 meander lobes sampled, comprising 34%, 62%, and 61% of all Russian olive and plains cottonwood seedlings, saplings, and trees, respectively. On some meander lobes, Russian olive has colonized similar elevations on the floodplain as plains cottonwood and is oriented in rows paralleling the river channel, suggesting that recruitment may be related to river processes. Breakup ice had killed 400 Russian olive saplings and trees and damaged >1000 others on 30 of the meander lobes in 1996. Nevertheless, Russian olive now outnumbers cottonwood on many sites on the Milk River floodplain because its seeds can be dispersed by wildlife (particularly birds) and probably by flood water and ice rafts; seeds are viable for up to 3 years and germination can take place on bare and well-vegetated soils; and saplings and trees are less palatable to livestock and beaver than plains cottonwood. Without control, Russian olive could be locally dominant on the Milk River floodplain in all age classes within 10 years and replace plains cottonwood within this century.

  11. Ert Applied to the Characterization of Subsidence in Mexico City: Ancient Structures Affecting Urban Utilities

    NASA Astrophysics Data System (ADS)

    Arango, C.; Chavez, R. E.; Cifuentes-Nava, G.; Hernández-Quintero, E.

    2013-05-01

    The problem of subsidence in Mexico City is basically due to the rapid extraction of groundwater for water supply in addition to the geological conditions. The most typical manifestations of the phenomena are presented as cracks and fractures due to compaction of ancient lake clayish sediments. This phenomenon has caused major affectations to city infrastructure because of the differential subsidence. Fractured buildings, sinkholes, among others manifestations, are potentially sources of collapses, which exposes the population to a serious risk. A small portion of Iztacalco County is being affected by this problem, specifically, in a crossroad formed by two important avenues: La Viga and Plutarco Elias Calles, where the area apparently increases its topographical level. The Electrical Resistivity Tomography technique was selected in order to obtain a resistivity image of the subsoil, which allows identify the main features associated to the terrain uprising. Three (ERT) profiles 200 m, were deployed on the mentioned crossroad in order to characterize the subsurface structures affecting the topographical level of the avenues. A big resistivity anomaly (~ 1000 ohm-m) could be observed towards the central part of the crossroad, coinciding with the major lifting level on surface. This feature appears at 15 m deep in all the profiles and depicts an approximate extension of 100 m in the E-W direction and 60 m in N-S axis. On the other hand, the surrounding material seems to correspond to a higher-saturated environment (lacustrine sediments <10 ohm-m). Shallow anomalies were also detected related to urban artifacts (pipes, sewers, etcetera). The apparently terrain uprising can be associated to a differential subsidence. However, the mentioned avenues were ancient water channels since pre-Hispanic times, where the caudal was enough to allow small steam boating at late nineteenth century. These waterways served as main routes for the exchange of goods during colonial times

  12. The soil carbon/nitrogen ratio and moisture affect microbial community structures in alkaline permafrost-affected soils with different vegetation types on the Tibetan plateau.

    PubMed

    Zhang, Xinfang; Xu, Shijian; Li, Changming; Zhao, Lin; Feng, Huyuan; Yue, Guangyang; Ren, Zhengwei; Cheng, Guogdong

    2014-01-01

    In the Tibetan permafrost region, vegetation types and soil properties have been affected by permafrost degradation, but little is known about the corresponding patterns of their soil microbial communities. Thus, we analyzed the effects of vegetation types and their covariant soil properties on bacterial and fungal community structure and membership and bacterial community-level physiological patterns. Pyrosequencing and Biolog EcoPlates were used to analyze 19 permafrost-affected soil samples from four principal vegetation types: swamp meadow (SM), meadow (M), steppe (S) and desert steppe (DS). Proteobacteria, Acidobacteria, Bacteroidetes and Actinobacteria dominated bacterial communities and the main fungal phyla were Ascomycota, Basidiomycota and Mucoromycotina. The ratios of Proteobacteria/Acidobacteria decreased in the order: SM>M>S>DS, whereas the Ascomycota/Basidiomycota ratios increased. The distributions of carbon and nitrogen cycling bacterial genera detected were related to soil properties. The bacterial communities in SM/M soils degraded amines/amino acids very rapidly, while polymers were degraded rapidly by S/DS communities. UniFrac analysis of bacterial communities detected differences among vegetation types. The fungal UniFrac community patterns of SM differed from the others. Redundancy analysis showed that the carbon/nitrogen ratio had the main effect on bacteria community structures and their diversity in alkaline soil, whereas soil moisture was mainly responsible for structuring fungal communities. Thus, microbial communities and their functioning are probably affected by soil environmental change in response to permafrost degradation.

  13. Ubiquitin Ser65 phosphorylation affects ubiquitin structure, chain assembly and hydrolysis

    PubMed Central

    Wauer, Tobias; Swatek, Kirby N; Wagstaff, Jane L; Gladkova, Christina; Pruneda, Jonathan N; Michel, Martin A; Gersch, Malte; Johnson, Christopher M; Freund, Stefan MV; Komander, David

    2015-01-01

    The protein kinase PINK1 was recently shown to phosphorylate ubiquitin (Ub) on Ser65, and phosphoUb activates the E3 ligase Parkin allosterically. Here, we show that PINK1 can phosphorylate every Ub in Ub chains. Moreover, Ser65 phosphorylation alters Ub structure, generating two conformations in solution. A crystal structure of the major conformation resembles Ub but has altered surface properties. NMR reveals a second phosphoUb conformation in which β5-strand slippage retracts the C-terminal tail by two residues into the Ub core. We further show that phosphoUb has no effect on E1-mediated E2 charging but can affect discharging of E2 enzymes to form polyUb chains. Notably, UBE2R1- (CDC34), UBE2N/UBE2V1- (UBC13/UEV1A), TRAF6- and HOIP-mediated chain assembly is inhibited by phosphoUb. While Lys63-linked poly-phosphoUb is recognized by the TAB2 NZF Ub binding domain (UBD), 10 out of 12 deubiquitinases (DUBs), including USP8, USP15 and USP30, are impaired in hydrolyzing phosphoUb chains. Hence, Ub phosphorylation has repercussions for ubiquitination and deubiquitination cascades beyond Parkin activation and may provide an independent layer of regulation in the Ub system. PMID:25527291

  14. Copper sulfate affects Nile tilapia (Oreochromis niloticus) cardiomyocytes structure and contractile function.

    PubMed

    de Andrade Waldemarin, Kátia Cristina; Alves, Rosiane Nascimento; Beletti, Marcelo Emílio; Rantin, Francisco Tadeu; Kalinin, Ana Lúcia

    2012-04-01

    Copper sulfate (CuSO(4))is an inorganic chemical product worldwide used as an algaecide and a fungicide in aquaculture and agriculture and being discharged into freshwater environments where it can affect the freshwater fauna, especially fishes. The impact of copper on fish cardiac function was analyzed in two groups of Nile tilapias, Oreochromis niloticus (control group and group exposed to 1 mg l(-1) of CuSO(4) for 96 h). Structural and ultra-structural changes were studied and related to perturbations of the inotropic and chronotropic responses of ventricle strips. Fish of Cu exposed group did not show significant alterations in the medium diameter and in the percentage of collagen in the cardiac myocytes when evaluated through the light microscope. However, the ultrastructural analysis revealed cellular swelling followed by mitochondrial swelling. The myofibrils did not show significant variations among groups. Force contraction was significantly decreased, and rates of time to tension increase (contraction) and decrease (relaxation) were significantly augmented after copper exposure. The results suggest that the copper sulfate impairs the oxidative mitochondrial function and consequently alters the cardiac performance of this species.

  15. Ontogenetic shifts in plant interactions vary with environmental severity and affect population structure.

    PubMed

    le Roux, Peter C; Shaw, Justine D; Chown, Steven L

    2013-10-01

    Environmental conditions and plant size may both alter the outcome of inter-specific plant-plant interactions, with seedlings generally facilitated more strongly than larger individuals in stressful habitats. However, the combined impact of plant size and environmental severity on interactions is poorly understood. Here, we tested explicitly for the first time the hypothesis that ontogenetic shifts in interactions are delayed under increasingly severe conditions by examining the interaction between a grass, Agrostis magellanica, and a cushion plant, Azorella selago, along two severity gradients. The impact of A. selago on A. magellanica abundance, but not reproductive effort, was related to A. magellanica size, with a trend for delayed shifts towards more negative interactions under greater environmental severity. Intermediate-sized individuals were most strongly facilitated, leading to differences in the size-class distribution of A. magellanica on the soil and on A. selago. The A. magellanica size-class distribution was more strongly affected by A. selago than by environmental severity, demonstrating that the plant-plant interaction impacts A. magellanica population structure more strongly than habitat conditions. As ontogenetic shifts in plant-plant interactions cannot be assumed to be constant across severity gradients and may impact species population structure, studies examining the outcome of interactions need to consider the potential for size- or age-related variation in competition and facilitation.

  16. An Analysis of the Structural Factors Affecting the Public Participation in Health Promotion

    PubMed Central

    Ghaumi, Raheleh; Aminee, Tayebe; Aminaee, Akram; Dastoury, Mojgan

    2016-01-01

    The present study focuses on analyzing national and international Community-Based Participatory Research (CBPR) studies published from 2000 to 2012 in order to identify and categorize the possible factors that affect social participation for improving the public health. Clearly, improving the public health necessitates a combination of the participation and responsibility by the social members and the attempts by public health policy-makers and planners. CBPR studies are selected as the corpus since they seek to encourage active and informed participation of the social members in fulfilling the health related goals. The present study is conducted through meta-synthesis within a qualitative framework. The results revealed a set of factors within the structural capacities which were employed by the CBPR researchers for achieving the health promotion goals. The structural capacities employed in the interventions could be considered on the cultural and social grounds. The cultural grounds were divided into scientific and religious attempts. For the scientific attempts, the results highlighted the participation of higher education institutes including universities and research centers as well as educational institutes such as schools and the relevant institutions. And regarding the religious attempts, the results indicated that the cooptation of religious centers played the greatest role in enhancing the public participation. PMID:27045401

  17. An Analysis of the Structural Factors Affecting the Public Participation in Health Promotion.

    PubMed

    Ghaumi, Raheleh; Aminee, Tayebe; Aminaee, Akram; Dastoury, Mojgan

    2016-01-01

    The present study focuses on analyzing national and international Community-Based Participatory Research (CBPR) studies published from 2000 to 2010 in order to identify and categorize the possible factors that affect social participation for improving the public health. Clearly, improving the public health necessitates a combination of the participation and responsibility by the social members and the attempts by public health policy-makers and planners. CBPR studies are selected as the corpus since they seek to encourage active and informed participation of the social members in fulfilling the health related goals. The present study is conducted through meta-synthesis within a qualitative framework. The results revealed a set of factors within the structural capacities which were employed by the CBPR researchers for achieving the health promotion goals. The structural capacities employed in the interventions could be considered on the cultural and social grounds. The cultural grounds were divided into scientific and religious attempts. For the scientific attempts, the results highlighted the participation of higher education institutes including universities and research centers as well as educational institutes such as schools and the relevant institutions. And regarding the religious attempts, the results indicated that the cooptation of religious centers played the greatest role in enhancing the public participation. PMID:27045401

  18. The risk of river pollution due to washout from contaminated floodplain water bodies during high floods

    NASA Astrophysics Data System (ADS)

    Lyubimova, Tatyana; Lepikhin, Anatoly; Parshakova, Yanina; Tiunov, Alexey

    2016-04-01

    Today, the potential impact of extremely high floods, which in the last years have become a rather frequent weather-related disaster, is the problem of primary concern. In studies of the potential impact of floods the emphasis is placed first of all on the estimation of possible flood zones and the analysis of the flow regimes in these zones. However, in some cases the hydrochemical parameters related to changes in the chemical composition of water are more important than the hydraulic parameters. It is generally believed that the higher is the flow rate, the more intensive is the process of dissolution, i.e. the lower is the concentration of limiting contaminants in water. However, this statement is valid provided that flooding does not activate new sources of water pollution such as contaminated floodplain water bodies located in the vicinity of water supply systems. Being quite reliable and safe at small and moderate discharges, in the case of extremely high level of river waters they become intensive sources of water pollution, essentially limiting the water consumption schedule for downstream water consumers. It should be noted that compared to the well-studied mechanisms of waste discharge due to failure of hydraulic engineering structures by flood waves, the mechanisms of pollutant washout from the contaminated floodplain water bodies by the flood waves is still poorly understood. We analyze the impacts of such weather-related events on the quality of water in the water intake system, taking as an example, the section of the Vyatka River located in the Prikamskaya lowland of the Russian Federation. The risk of river pollution due to washout from the contaminated floodplain water bodies during high floods is studied by hydrodynamical modeling in the framework of combined approach using one-, two- and three-dimensional hydrodynamic models are implemented and by in situ measurements. It is shown that during high floods the removal of pollutants from the

  19. Relative significance of microtopography and vegetation as controls on surface water flow on a low-gradient floodplain

    USGS Publications Warehouse

    Choi, Jungyill; Harvey, Judson W.

    2014-01-01

    Surface water flow controls water velocities, water depths, and residence times, and influences sediment and nutrient transport and other ecological processes in shallow aquatic systems. Flow through wetlands is substantially influenced by drag on vegetation stems but is also affected by microtopography. Our goal was to use microtopography data directly in a widely used wetland model while retaining the advantages of the model’s one-dimensional structure. The base simulation with no explicit treatment of microtopography only performed well for a period of high water when vegetation dominated flow resistance. Extended simulations using microtopography can improve the fit to low-water conditions substantially. The best fit simulation had a flow conductance parameter that decreased in value by 70 % during dry season such that mcrotopographic features blocked 40 % of the cross sectional width for flow. Modeled surface water became ponded and flow ceased when 85 % of the cross sectional width became blocked by microtopographic features. We conclude that vegetation drag dominates wetland flow resistance at higher water levels and microtopography dominates at low water levels with the threshold delineated by the top of microtopographic features. Our results support the practicality of predicting flow on floodplains using relatively easily measured physical and biological variables.

  20. Remnant Trees Affect Species Composition but Not Structure of Tropical Second-Growth Forest

    PubMed Central

    Sandor, Manette E.; Chazdon, Robin L.

    2014-01-01

    Remnant trees, spared from cutting when tropical forests are cleared for agriculture or grazing, act as nuclei of forest regeneration following field abandonment. Previous studies on remnant trees were primarily conducted in active pasture or old fields abandoned in the previous 2–3 years, and focused on structure and species richness of regenerating forest, but not species composition. Our study is among the first to investigate the effects of remnant trees on neighborhood forest structure, biodiversity, and species composition 20 years post-abandonment. We compared the woody vegetation around individual remnant trees to nearby plots without remnant trees in the same second-growth forests (“control plots”). Forest structure beneath remnant trees did not differ significantly from control plots. Species richness and species diversity were significantly higher around remnant trees. The species composition around remnant trees differed significantly from control plots and more closely resembled the species composition of nearby old-growth forest. The proportion of old-growth specialists and generalists around remnant trees was significantly greater than in control plots. Although previous studies show that remnant trees may initially accelerate secondary forest growth, we found no evidence that they locally affect stem density, basal area, and seedling density at later stages of regrowth. Remnant trees do, however, have a clear effect on the species diversity, composition, and ecological groups of the surrounding woody vegetation, even after 20 years of forest regeneration. To accelerate the return of diversity and old-growth forest species into regrowing forest on abandoned land, landowners should be encouraged to retain remnant trees in agricultural or pastoral fields. PMID:24454700

  1. Remnant trees affect species composition but not structure of tropical second-growth forest.

    PubMed

    Sandor, Manette E; Chazdon, Robin L

    2014-01-01

    Remnant trees, spared from cutting when tropical forests are cleared for agriculture or grazing, act as nuclei of forest regeneration following field abandonment. Previous studies on remnant trees were primarily conducted in active pasture or old fields abandoned in the previous 2-3 years, and focused on structure and species richness of regenerating forest, but not species composition. Our study is among the first to investigate the effects of remnant trees on neighborhood forest structure, biodiversity, and species composition 20 years post-abandonment. We compared the woody vegetation around individual remnant trees to nearby plots without remnant trees in the same second-growth forests ("control plots"). Forest structure beneath remnant trees did not differ significantly from control plots. Species richness and species diversity were significantly higher around remnant trees. The species composition around remnant trees differed significantly from control plots and more closely resembled the species composition of nearby old-growth forest. The proportion of old-growth specialists and generalists around remnant trees was significantly greater than in control plots. Although previous studies show that remnant trees may initially accelerate secondary forest growth, we found no evidence that they locally affect stem density, basal area, and seedling density at later stages of regrowth. Remnant trees do, however, have a clear effect on the species diversity, composition, and ecological groups of the surrounding woody vegetation, even after 20 years of forest regeneration. To accelerate the return of diversity and old-growth forest species into regrowing forest on abandoned land, landowners should be encouraged to retain remnant trees in agricultural or pastoral fields.

  2. Predicting the fate of sediment and pollutants in river floodplains.

    PubMed

    Malmon, Daniel V; Dunne, Thomas; Reneau, Steven L

    2002-05-01

    Geological processes such as erosion and sedimentation redistribute toxic pollutants introduced to the landscape by mining, agriculture, weapons development, and other human activities. A significant portion of these contaminants is insoluble, adsorbing to soils and sediments after being released. Geologists have long understood that much of this sediment is stored in river floodplains, which are increasingly recognized as important nonpoint sources of pollution in rivers. However, the fate of contaminated sediment has generally been analyzed using hydrodynamic models of in-channel processes, ignoring particle exchange with the floodplain. Here, we present a stochastic theory of sediment redistribution in alluvial valley floors that tracks particle-bound pollutants and explicitly considers sediment storage within floodplains. We use the theory to model the future redistribution and radioactive decay of 137Cs currently stored on sediment in floodplains at the Los Alamos National Laboratory (LANL) in New Mexico. Model results indicate that floodplain storage significantly reduces the rate of sediment delivery from upper Los Alamos Canyon, allowing 50% of the 137Cs currently residing in the valley floor to decay radioactively before leaving LANL. A sensitivity analysis shows that the rate of sediment overturn in the valley (and hence, the total amount of radioactive 137Cs predicted to leave LANL) is significantly controlled by the rate of sediment exchange with the floodplain. Our results emphasize that flood plain sedimentation and erosion processes can strongly influence the redistribution of anthropogenic pollutants in fluvial environments. We introduce a new theoretical framework for examining this interaction, which can provide a scientific basis for decision-making in a wide range of river basin management scenarios.

  3. Digital floodplain mapping and an analysis of errors involved

    USGS Publications Warehouse

    Hamblen, C.S.; Soong, D.T.; Cai, X.

    2007-01-01

    Mapping floodplain boundaries using geographical information system (GIS) and digital elevation models (DEMs) was completed in a recent study. However convenient this method may appear at first, the resulting maps potentially can have unaccounted errors. Mapping the floodplain using GIS is faster than mapping manually, and digital mapping is expected to be more common in the future. When mapping is done manually, the experience and judgment of the engineer or geographer completing the mapping and the contour resolution of the surface topography are critical in determining the flood-plain and floodway boundaries between cross sections. When mapping is done digitally, discrepancies can result from the use of the computing algorithm and digital topographic datasets. Understanding the possible sources of error and how the error accumulates through these processes is necessary for the validation of automated digital mapping. This study will evaluate the procedure of floodplain mapping using GIS and a 3 m by 3 m resolution DEM with a focus on the accumulated errors involved in the process. Within the GIS environment of this mapping method, the procedural steps of most interest, initially, include: (1) the accurate spatial representation of the stream centerline and cross sections, (2) properly using a triangulated irregular network (TIN) model for the flood elevations of the studied cross sections, the interpolated elevations between them and the extrapolated flood elevations beyond the cross sections, and (3) the comparison of the flood elevation TIN with the ground elevation DEM, from which the appropriate inundation boundaries are delineated. The study area involved is of relatively low topographic relief; thereby, making it representative of common suburban development and a prime setting for the need of accurately mapped floodplains. This paper emphasizes the impacts of integrating supplemental digital terrain data between cross sections on floodplain delineation

  4. Hydrogeomorphology influences soil nitrogen and phosphorus mineralization in floodplain wetlands

    USGS Publications Warehouse

    Noe, Gregory B.; Hupp, Cliff R.; Rybicki, Nancy B.

    2013-01-01

    Conceptual models of river–floodplain systems and biogeochemical theory predict that floodplain soil nitrogen (N) and phosphorus (P) mineralization should increase with hydrologic connectivity to the river and thus increase with distance downstream (longitudinal dimension) and in lower geomorphic units within the floodplain (lateral dimension). We measured rates of in situ soil net ammonification, nitrification, N, and P mineralization using monthly incubations of modified resin cores for a year in the forested floodplain wetlands of Difficult Run, a fifth order urban Piedmont river in Virginia, USA. Mineralization rates were then related to potentially controlling ecosystem attributes associated with hydrologic connectivity, soil characteristics, and vegetative inputs. Ammonification and P mineralization were greatest in the wet backswamps, nitrification was greatest in the dry levees, and net N mineralization was greatest in the intermediately wet toe-slopes. Nitrification also was greater in the headwater sites than downstream sites, whereas ammonification was greater in downstream sites. Annual net N mineralization increased with spatial gradients of greater ammonium loading to the soil surface associated with flooding, soil organic and nutrient content, and herbaceous nutrient inputs. Annual net P mineralization was associated negatively with soil pH and coarser soil texture, and positively with ammonium and phosphate loading to the soil surface associated with flooding. Within an intensively sampled low elevation flowpath at one site, sediment deposition during individual incubations stimulated mineralization of N and P. However, the amount of N and P mineralized in soil was substantially less than the amount deposited with sedimentation. In summary, greater inputs of nutrients and water and storage of soil nutrients along gradients of river–floodplain hydrologic connectivity increased floodplain soil nutrient mineralization rates.

  5. 76 FR 57716 - Notice of Availability of a Draft Companion Manual for Executive Order 11988 Floodplain...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-16

    ... Manual for Executive Order 11988 Floodplain Management and Executive Order 11990 Protection of Wetlands... agency-wide guidance for executing compliance with Executive Order 11988 Floodplain Management and... companion manual is to promote quality and consistency in implementing floodplain management and...

  6. 14 CFR 1216.205 - Procedures for evaluating NASA actions impacting floodplains and wetlands.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... impacting floodplains and wetlands. 1216.205 Section 1216.205 Aeronautics and Space NATIONAL AERONAUTICS AND SPACE ADMINISTRATION ENVIRONMENTAL QUALITY Floodplain and Wetlands Management § 1216.205 Procedures for evaluating NASA actions impacting floodplains and wetlands. (a) Before taking any action a...

  7. 14 CFR 1216.205 - Procedures for evaluating NASA actions impacting floodplains and wetlands.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... impacting floodplains and wetlands. 1216.205 Section 1216.205 Aeronautics and Space NATIONAL AERONAUTICS AND SPACE ADMINISTRATION ENVIRONMENTAL QUALITY Floodplain and Wetlands Management § 1216.205 Procedures for evaluating NASA actions impacting floodplains and wetlands. (a) Before taking any action a...

  8. 14 CFR 1216.205 - Procedures for evaluating NASA actions impacting floodplains and wetlands.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... impacting floodplains and wetlands. 1216.205 Section 1216.205 Aeronautics and Space NATIONAL AERONAUTICS AND SPACE ADMINISTRATION ENVIRONMENTAL QUALITY Floodplain and Wetlands Management § 1216.205 Procedures for evaluating NASA actions impacting floodplains and wetlands. (a) Before taking any action a...

  9. 14 CFR 1216.205 - Procedures for evaluating NASA actions impacting floodplains and wetlands.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... impacting floodplains and wetlands. 1216.205 Section 1216.205 Aeronautics and Space NATIONAL AERONAUTICS AND SPACE ADMINISTRATION ENVIRONMENTAL QUALITY Floodplain and Wetlands Management § 1216.205 Procedures for evaluating NASA actions impacting floodplains and wetlands. (a) Before taking any action a...

  10. Determination of 100-year floodplain elevations at Los Alamos National Laboratory

    SciTech Connect

    McLin, S.G.

    1992-08-01

    Under existing permit requirements. the US Environmental Protection Agency stipulates that facilities regulated by the Resource Conservation and Recovery Act must delineate all 100-yr floodplain elevations within their boundaries. At Los Alamos these floodplains are located within ungaged watersheds that drain Pajarito Plateau. This report documents the floodplain computational mapping procedure and, along with supporting maps, is untended to satisfy this permit requirement.

  11. 13 CFR 120.172 - Flood-plain and wetlands management.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 11988, “Flood Plain Management” (3 CFR, 1977 Comp., p. 117) and 11990, “Protection of Wetlands” (3 CFR... floodplain or wetland; (2) If it is in a floodplain, that the assistance is in compliance with local land use... (determining if a proposed action is in the base floodplain) need be completed: (1) Actions located outside...

  12. 14 CFR § 1216.205 - Procedures for evaluating NASA actions impacting floodplains and wetlands.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... impacting floodplains and wetlands. § 1216.205 Section § 1216.205 Aeronautics and Space NATIONAL AERONAUTICS AND SPACE ADMINISTRATION ENVIRONMENTAL QUALITY Floodplain and Wetlands Management § 1216.205 Procedures for evaluating NASA actions impacting floodplains and wetlands. (a) Before taking any action...

  13. 77 FR 56189 - Proposed Information Collection; Comment Request; Elwha River Dam Removal and Floodplain...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-09-12

    ... River Dam Removal and Floodplain Restoration Ecosystem Service Valuation Pilot Project AGENCY: National... Elwha River Dam Removal and Floodplain Restoration Ecosystem Service Valuation Survey it has developed... U.S. history. This project, along with restoration actions planned for the floodplain and...

  14. Earthworm-Mycorrhiza Interactions Can Affect the Diversity, Structure and Functioning of Establishing Model Grassland Communities

    PubMed Central

    Zaller, Johann G.; Heigl, Florian; Grabmaier, Andrea; Lichtenegger, Claudia; Piller, Katja; Allabashi, Roza; Frank, Thomas; Drapela, Thomas

    2011-01-01

    Both earthworms and arbuscular mycorrhizal fungi (AMF) are important ecosystem engineers co-occurring in temperate grasslands. However, their combined impacts during grassland establishment are poorly understood and have never been studied. We used large mesocosms to study the effects of different functional groups of earthworms (i.e., vertically burrowing anecics vs. horizontally burrowing endogeics) and a mix of four AMF taxa on the establishment, diversity and productivity of plant communities after a simulated seed rain of 18 grassland species comprising grasses, non-leguminous forbs and legumes. Moreover, effects of earthworms and/or AMF on water infiltration and leaching of ammonium, nitrate and phosphate were determined after a simulated extreme rainfall event (40 l m−2). AMF colonisation of all three plant functional groups was altered by earthworms. Seedling emergence and diversity was reduced by anecic earthworms, however only when AMF were present. Plant density was decreased in AMF-free mesocosms when both anecic and endogeic earthworms were active; with AMF also anecics reduced plant density. Plant shoot and root biomass was only affected by earthworms in AMF-free mesocosms: shoot biomass increased due to the activity of either anecics or endogeics; root biomass increased only when anecics were active. Water infiltration increased when earthworms were present in the mesocosms but remained unaffected by AMF. Ammonium leaching was increased only when anecics or a mixed earthworm community was active but was unaffected by AMF; nitrate and phosphate leaching was neither affected by earthworms nor AMF. Ammonium leaching decreased with increasing plant density, nitrate leaching decreased with increasing plant diversity and density. In order to understand the underlying processes of these interactions further investigations possibly under field conditions using more diverse belowground communities are required. Nevertheless, this study demonstrates that

  15. Linking Geology and Microbiology: Inactive Pockmarks Affect Sediment Microbial Community Structure

    PubMed Central

    Haverkamp, Thomas H. A.; Hammer, Øyvind; Jakobsen, Kjetill S.

    2014-01-01

    Pockmarks are geological features that are found on the bottom of lakes and oceans all over the globe. Some are active, seeping oil or methane, while others are inactive. Active pockmarks are well studied since they harbor specialized microbial communities that proliferate on the seeping compounds. Such communities are not found in inactive pockmarks. Interestingly, inactive pockmarks are known to have different macrofaunal communities compared to the surrounding sediments. It is undetermined what the microbial composition of inactive pockmarks is and if it shows a similar pattern as the macrofauna. The Norwegian Oslofjord contains many inactive pockmarks and they are well suited to study the influence of these geological features on the microbial community in the sediment. Here we present a detailed analysis of the microbial communities found in three inactive pockmarks and two control samples at two core depth intervals. The communities were analyzed using high-throughput amplicon sequencing of the 16S rRNA V3 region. Microbial communities of surface pockmark sediments were indistinguishable from communities found in the surrounding seabed. In contrast, pockmark communities at 40 cm sediment depth had a significantly different community structure from normal sediments at the same depth. Statistical analysis of chemical variables indicated significant differences in the concentrations of total carbon and non-particulate organic carbon between 40 cm pockmarks and reference sample sediments. We discuss these results in comparison with the taxonomic classification of the OTUs identified in our samples. Our results indicate that microbial communities at the sediment surface are affected by the water column, while the deeper (40 cm) sediment communities are affected by local conditions within the sediment. PMID:24475066

  16. Linking geology and microbiology: inactive pockmarks affect sediment microbial community structure.

    PubMed

    Haverkamp, Thomas H A; Hammer, Øyvind; Jakobsen, Kjetill S

    2014-01-01

    Pockmarks are geological features that are found on the bottom of lakes and oceans all over the globe. Some are active, seeping oil or methane, while others are inactive. Active pockmarks are well studied since they harbor specialized microbial communities that proliferate on the seeping compounds. Such communities are not found in inactive pockmarks. Interestingly, inactive pockmarks are known to have different macrofaunal communities compared to the surrounding sediments. It is undetermined what the microbial composition of inactive pockmarks is and if it shows a similar pattern as the macrofauna. The Norwegian Oslofjord contains many inactive pockmarks and they are well suited to study the influence of these geological features on the microbial community in the sediment. Here we present a detailed analysis of the microbial communities found in three inactive pockmarks and two control samples at two core depth intervals. The communities were analyzed using high-throughput amplicon sequencing of the 16S rRNA V3 region. Microbial communities of surface pockmark sediments were indistinguishable from communities found in the surrounding seabed. In contrast, pockmark communities at 40 cm sediment depth had a significantly different community structure from normal sediments at the same depth. Statistical analysis of chemical variables indicated significant differences in the concentrations of total carbon and non-particulate organic carbon between 40 cm pockmarks and reference sample sediments. We discuss these results in comparison with the taxonomic classification of the OTUs identified in our samples. Our results indicate that microbial communities at the sediment surface are affected by the water column, while the deeper (40 cm) sediment communities are affected by local conditions within the sediment.

  17. Steroidal aromatic 'naphthenic acids' in oil sands process-affected water: structural comparisons with environmental estrogens.

    PubMed

    Rowland, Steven J; West, Charles E; Jones, David; Scarlett, Alan G; Frank, Richard A; Hewitt, L Mark

    2011-11-15

    The large volumes, acute toxicity, estrogenicity, and antiandrogenicity of process-affected waters accruing in tailings ponds from the operations of the Alberta oil sands industries pose a significant task for environmental reclamation. Synchronous fluorescence spectra (SFS) suggest that oil sands process-affected water (OSPW) may contain aromatic carboxylic acids, which are among the potentially environmentally important toxicants, but no such acids have yet been identified, limiting interpretations of the results of estrogenicity and other assays. Here we show that multidimensional comprehensive gas chromatography-mass spectrometry (GCxGC-MS) of methyl esters of acids in an OSPW sample produces mass spectra consistent with their assignment as C(19) and C(20) C-ring monoaromatic hydroxy steroid acids, D-ring opened hydroxy and nonhydroxy polyhydrophenanthroic acids with one aromatic and two alicyclic rings and A-ring opened steroidal keto acids. High resolution MS data support the assignment of several of the so-called 'O3' species. When fractions of distilled, esterified, OSPW acid-extractable organics were examined, the putative aromatics were mainly present in a high boiling fraction; when examined by argentation thin layer chromatography, some were present in a fraction with a retardation factor between that of the methyl esters of synthetic monoalicyclic and monoaromatic acids. Ultraviolet absorption spectra of these fractions indicated the presence of benzenoid moieties. SFS of model octahydro- and tetrahydrophenanthroic acids produced emissions at the characteristic excitation wavelengths observed in some OSPW extracts, consistent with the postulations from ultraviolet spectroscopy and mass spectrometry data. We suggest the acids originate from extensive biodegradation of C-ring monoaromatic steroid hydrocarbons and offer a means of differentiating residues at different biodegradation stages in tailings ponds. Structural similarities with estrone and

  18. A Conceptual Model for Floodplains in California's Central Valley and a Method for Identifying Representative Floods and Floodplains

    NASA Astrophysics Data System (ADS)

    Opperman, J. J.; Andrews, E.; Bozkurt, S.; Mount, J. F.; Moyle, P. B.

    2005-05-01

    Currently, significant resources are being invested in restoring native species and ecosystems in California's Central Valley and the Sacramento-San Joaquin Delta, led by the California Bay-Delta Authority (CBDA). Functioning floodplains provide numerous ecological benefits and floodplain restoration is emerging as important component of ecosystem restoration in this region. We developed a conceptual model that describes the linkages between physical (hydrologic and geomorphic) processes and ecosystem processes and responses on Central Valley floodplains. Central to this model is the role of hydrological variability in driving topographic diversity, ecosystem heterogeneity and ecological processes. We attempt to capture the extremely complex linkages between hydrological variability and ecosystem response through `representative floods.' A representative flood encompasses a set of hydrological variables, such as frequency and duration, which produce a characteristic suite of ecological benefits. For example, frequent, long duration flooding in the spring provides spawning and rearing habitat for native fish and promotes high phytoplankton productivity which can be exported to riverine and delta ecosystems. Less frequent, higher magnitude floods drive extensive geomorphic change upon the floodplain, creating topographic and, ultimately, ecological heterogeneity. Here we describe a process to define, map, and quantify the area inundated by a particular representative flood in the Sacramento River valley. To illustrate we identify the area inundated by a frequent (exceedance probability of 67%), long duration (> 7 days) flood that occurs in the spring. We used paired gauges to find the stage corresponding to the representative flood parameters and compared a plane connecting the gauges to topography in the intervening reach of river. We found that this type of representative flood inundates very little area in the Sacramento Valley; primary areas of inundation are

  19. River mobility in a permafrost dominated floodplain

    NASA Astrophysics Data System (ADS)

    Rowland, J.; Wilson, C.; Brumby, S.; Pope, P.

    2009-04-01

    Along arctic coastlines, recent studies have attributed dramatic increases in the rates of shoreline erosion to global climate change and permafrost degradation. While across much of the arctic, changes in the size and number of lakes have been interpreted as the result of permafrost degradation altering surface water dynamics. The potential influence of climate change and permafrost thawing on the mobility and form of arctic rivers, however, has been relatively unexplored to date. In rivers located within permafrost, some to potentially most, of the cohesive bank strength may be derived from frozen materials. It is likely that, as permafrost thaws, river bank erosion may increase, in turn influencing both migration rates and channel planform. Using automated feature extraction software (GeniePro), we quantified the of the mobility of a 200 km reach of the Yukon River through the Yukon Flats region located just north of Fairbanks, Alaska, USA. The Yukon Flats is an area of comprised of both continuous and discontinuous permafrost. Based on both changes in lake distributions and wintertime river base flows, it has been suggested that permafrost in this area has been experiencing recent thawing. In this reach, the Yukon River transitions from a 2 km wide braided channel to a multi-thread meandering channel where individual threads are approximately 1 km wide and the floodplain preserves prior meander cutoffs and oxbow lakes. Preliminary results from thirty years of LANDSAT imagery shows a surprising stability of channel location (at the image resolution of 30m/pixel) given the channel form. Within the braid-belt there is localized relocation of channel threads and mid-channel islands, though along much of the reach, the change in the location of channels banks is close to the resolution of the imagery. At the most active bends, bank migration rates range from 0.007 to 0.02 channel widths per year. These rates are comparable to system wide average rates observed on

  20. Drama and the Representation of Affect--Structures of Feeling and Signs of Learning

    ERIC Educational Resources Information Center

    Franks, Anton

    2014-01-01

    The way in which school students represent affective aspects of human relationships in drama and what this reveals about learning in drama is the focus of this paper. Such an enquiry traverses the borders between affect, intellect, and physicality. Affect and its representation in drama have been themes in the history of drama and theatre and is a…

  1. A Structure for the Affective Domain in Relation to Science Education.

    ERIC Educational Resources Information Center

    Klopfer, Leopold E.

    A classification scheme for the affective domain in relation to science education is presented in this article to clarify student's affective behaviors and their representative phenomena. Discussion is made in connection with the content-objectives grid in the cognitive domain. An analogous grid for the affective domain is delineated by a…

  2. Does the tail wag the dog? How the structure of a glycosylphosphatidylinositol anchor affects prion formation.

    PubMed

    Bate, Clive; Nolan, William; Williams, Alun

    2016-03-01

    There is increasing interest in the role of the glycosylphosphatidylinositol (GPI) anchor attached to the cellular prion protein (PrP(C)). Since GPI anchors can alter protein targeting, trafficking and cell signaling, our recent study examined how the structure of the GPI anchor affected prion formation. PrP(C) containing a GPI anchor from which the sialic acid had been removed (desialylated PrP(C)) was not converted to PrP(Sc) in prion-infected neuronal cell lines and in scrapie-infected primary cortical neurons. In uninfected neurons desialylated PrP(C) was associated with greater concentrations of gangliosides and cholesterol than PrP(C). In addition, the targeting of desialylated PrP(C) to lipid rafts showed greater resistance to cholesterol depletion than PrP(C). The presence of desialylated PrP(C) caused the dissociation of cytoplasmic phospholipase A2 (cPLA2) from PrP-containing lipid rafts, reduced the activation of cPLA2 and inhibited PrP(Sc) production. We conclude that the sialic acid moiety of the GPI attached to PrP(C) modifies local membrane microenvironments that are important in PrP-mediated cell signaling and PrP(Sc) formation. PMID:26901126

  3. Water molecules inside protein structure affect binding of monosaccharides with HIV-1 antibody 2G12.

    PubMed

    Ueno-Noto, Kaori; Takano, Keiko

    2016-10-01

    Water molecules inside biomolecules constitute integral parts of their structure and participate in the functions of the proteins. Some of the X-ray crystallographic data are insufficient for analyzing a series of ligand-protein complexes in the same condition. We theoretically investigated antibody binding abilities of saccharide ligands and the effects of the inner water molecules of ligand-antibody complexes. Classical molecular dynamics and quantum chemical simulations using a model with possible water molecules inside the protein were performed with saccharide ligands and Human Immunodeficiency Virus 1 neutralizing antibody 2G12 complexes to estimate how inner water molecules of the protein affect the dynamics of the complexes as well as the ligand-antibody interaction. Our results indicate the fact that d-fructose's strong affinity to the antibody was partly due to the good retentiveness of solvent water molecules of the ligand and its stability of the ligand's conformation and relative position in the active site. © 2016 Wiley Periodicals, Inc.

  4. Structure and Validity of Affect Knowledge Test (AKT) in a Sample of Italian Preschoolers.

    PubMed

    Sette, Stefania; Bassett, Hideko H; Baumgartner, Emma; Denham, Susanne A

    2015-01-01

    The authors' main goals were to examine whether the Affect Knowledge Test's (AKT) factor structure would be represented by a two-factor model (i.e., emotion recognition and situation knowledge) or by a one-factor model in Italian preschoolers (N = 164; M = 4.24 years, SD = 1.09 years). The concurrent validity of the AKT was further examined using measures of social competence. The findings replicated a model of emotion knowledge, with emotion recognition and situation knowledge as distinct but interrelated factors. Gender and age differences showed that older children and girls displayed higher scores in situation knowledge than younger children and boys. Additionally, our validity model of the AKT demonstrated that emotion recognition preceded situation knowledge, which in turn was positively related to children's sensitive or cooperative behaviors and negatively associated with anxious or withdrawn behaviors. Our results suggest that the use of the AKT may help the teachers to evaluate children's level on emotional knowledge that in turn might impact on children's positive social relationships within classroom in Italy.

  5. Inhibitors of plant invertases do not affect the structurally related enzymes of fructan metabolism.

    PubMed

    Kusch, Ute; Harms, Karsten; Rausch, Thomas; Greiner, Steffen

    2009-01-01

    Plant fructan active enzymes (FAZYs), including the enzymes involved in inulin metabolism, namely sucrose:sucrose 1-fructosyltransferase (1-SST; EC 2.4.1.99), fructan:fructan 1-fructosyltransferase (1-FFT; EC 2.4.1.100) and fructan 1-exohydrolase (1-FEH; EC 3.2.1.153), are evolutionarily related to acid invertases (AIs), that is, plant cell wall invertase (CWI) and vacuolar invertase (VI). Acid invertases are post-translationally controlled by proteinaceous inhibitors. Whether FAZYs are subject to similar controls is not known. To probe their possible interactions with invertase inhibitors, we transiently expressed chicory (Cichorium intybus) FAZYs, as well as several previously characterized invertase inhibitors from nonfructan species, and the C. intybus cell wall/vacuolar inhibitor of fructosidase (CiC/VIF), a putative invertase inhibitor of a fructan-accumulating plant, in leaves of Nicotiana benthamiana. Leaf extracts containing recombinant, enzymatically active FAZYs were used to explore the interaction with invertase inhibitors. Neither heterologous inhibitors nor CiC/VIF affected FAZY activities. CiC/VIF was confirmed as an AI inhibitor with a stronger effect on CWI than on VI. Its expression in planta was developmentally regulated (high in taproots, and undetectable in leaves and flowers). In agreement with its target specificities, CiC/VIF was associated with the cell wall. It is concluded that subtle structural differences between AIs and FAZYs result in pronounced selectivity of inhibitor action.

  6. Water molecules inside protein structure affect binding of monosaccharides with HIV-1 antibody 2G12.

    PubMed

    Ueno-Noto, Kaori; Takano, Keiko

    2016-10-01

    Water molecules inside biomolecules constitute integral parts of their structure and participate in the functions of the proteins. Some of the X-ray crystallographic data are insufficient for analyzing a series of ligand-protein complexes in the same condition. We theoretically investigated antibody binding abilities of saccharide ligands and the effects of the inner water molecules of ligand-antibody complexes. Classical molecular dynamics and quantum chemical simulations using a model with possible water molecules inside the protein were performed with saccharide ligands and Human Immunodeficiency Virus 1 neutralizing antibody 2G12 complexes to estimate how inner water molecules of the protein affect the dynamics of the complexes as well as the ligand-antibody interaction. Our results indicate the fact that d-fructose's strong affinity to the antibody was partly due to the good retentiveness of solvent water molecules of the ligand and its stability of the ligand's conformation and relative position in the active site. © 2016 Wiley Periodicals, Inc. PMID:27388036

  7. Geological Processes Affecting the Thermal Structures of Shallow Seafloor: An Example from offshore SW Taiwan

    NASA Astrophysics Data System (ADS)

    Chen, Liwen; Chi, Wu-Cheng; Wu, Shao-Kai; Liu, Char-Shine; Lu, Chia-Yu

    2014-05-01

    Fluid migration pattern is important for understanding the structural features of a mountain belt and for hydrocarbon exploration. However, these patterns are difficult to measure on the seafloor. Using phase properties of the gas hydrates, we studied the fluid flow patterns offshore southwestern Taiwan. Seismic explorations in this region show wide spreading bottom-simulating-reflectors (BSR), which is interpreted as the bottom of the gas hydrate stability zone. It provides us an opportunity to study possible fluid flow patterns at several hundred meters sub-bottom depths of the marine sediments. First, we used BSR-based geothermal gradient patterns to derive 1D vertical fluid flow models by analyzing the Péclet numbers. We found the regional fluid flow rates ranges from 6 cm/yr to 43 cm/yr, then we also discovered several prospect sites to examine the fluid migration pattern in the environs of active, passive and deformation front. Next, we forward 2D steady-state temperature fields of these sites to account for the topographic effects to compare with the BSR-based temperature. The discrepancy between the 2D conductive thermal model and the BSR-based temperature was interpreted as a result of fluid migration. And furthermore, we built 3D steady-state temperature fields, for comparing with BSR-based temperatures, to detail describe the regional temperature discrepancy with the structure evolution in 3D seismic data. We discovered our interpreted fluid migration patterns are consistent with the regional structure. The BSR-based temperatures in Yung-An Ridge, which is in active margin, are higher than the conduction model near faults and chimney zones, we interpret that it is possible active dewatering inside the accretionary prism to allow fluid to migrate upward here. For the upper reach of Peng-Hu Canyon, which is across deformation front, we found the disequilibrium temperature field probably induced by the recently landslide. For the Formosa Ridge in passive

  8. Hydrologic Controls over Water Use in a Forested Floodplain Wetland

    NASA Astrophysics Data System (ADS)

    Allen, S. T.; Cochran, J. W.; Keim, R.; King, S. L.; Krauss, K. W.

    2014-12-01

    Hydrologic variability is a primary driver of wetland forest physiological function and structure. Spatial variations in forest composition co-occur with hydrologic variations, generally assumed to be due to differences in tolerance to flooding and drought. To develop a process-level understanding of water table effects on wetland tree function, we measured transpiration of dominant bottomland hardwood species and analyzed how transpiration responded to spatial and temporal water table variations. Sap flow was measured with Granier-style heat dissipation probes in twenty-six trees (Celtis laevigata and Quercus lyrata) at two sites in the White River floodplain in Arkansas, USA (July - October, 2013). Hydrology at one site is controlled by headwater flooding driven by precipitation events. The other site is controlled by Mississippi River backwater flooding, where artificial levees cause high flood levels with rapid recession. Both sites have alluvial clay soils. At the backwater site, the receding water table corresponded with a steady reduction in transpiration throughout the growing season, suggesting that precipitation recharge of soil moisture did not satisfy demands despite the humid climate. In contrast, at the headwater site, precipitation events repeatedly raised the water table, which were mirrored by increases in transpiration. These results suggest preferential uptake from the free water surface over more tightly bound soil water, and that subsurface flood subsidies enable a longer effective growing season. Despite divergent growth strategies between the two monitored species, differences among the temporal patterns of transpiration depended more on microtopographic position rather than species. Recharge events by precipitation provided greater benefit for trees in microtopographic lows compared to those on ridges, evident by relatively higher sapflow rates, during the groundwater recession limb. Despite the similar species composition between sites

  9. Topographic changes detection through Structure-from-Motion in agricultural lands affected by erosion processes

    NASA Astrophysics Data System (ADS)

    Prosdocimi, Massimo; Pradetto Sordo, Nicoletta; Burguet, Maria; Di Prima, Simone; Terol Esparza, Enric; Tarolli, Paolo; Cerdà, Artemi

    2016-04-01

    Throughout the world, soil erosion by water is a serious problem, especially in semi-arid and semi-humid areas (Cerdà et al., 2009; Cerdan et al., 2010; García-Ruiz, 2010). Although soil erosion by water consists of physical processes that vary significantly in severity and frequency according to when and where they occur, they are also strongly influenced by anthropic factors such as land-use changes on large scales and unsustainable farming practices (Boardman et al., 1990; Cerdà 1994; Montgomery, 2007). Tillage operations, combined with weather conditions, are recognized to primarily influence soil erosion rates. If, on one hand, tillage operations cause uniform changes based on the tool used, on the other, weather conditions, such as rainfalls, produce more random changes, less easily traceable (Snapir et al., 2014). Within this context, remote-sensing technologies can facilitate the detection and quantification of these topographic changes. In particular, a real opportunity and challenge is offered by the low-cost and flexible photogrammetric technique, called 'Structure-from-Motion' (SfM), combined with the use of smartphones (Micheletti et al., 2014; Prosdocimi et al., 2015). This represents a significant advance compared with more expensive technologies and applications (e.g. Terrestrial Laser Scanner - TLS) (Tarolli, 2014). This work wants to test the Structure from Motion to obtain high-resolution topography for the detection of topographic changes in agricultural lands affected by erosion processes. Two case studies were selected: i) a tilled plot characterized by bare soil and affected by rill erosion located in the hilly countryside of Marche region (central Italy), and ii) a Mediterranean vineyard located within the province of Valencia (south eastern Spain) where rainfall simulation experiments were carried out. Extensive photosets were obtained by using one standalone reflex digital camera and one smartphone built-in digital camera. Digital

  10. Flood effects on efflux and net production of nitrous oxide in river floodplain soils

    NASA Astrophysics Data System (ADS)

    Riaz, Muhammad; Bruderer, Christian; Niklaus, Pascal A.; Luster, Jörg

    2016-04-01

    addition, temperature, volumetric water content, as well as ammonium, nitrate and dissolved organic carbon in the soil solution were monitored at different depths in the observation plots. During not flood-affected conditions we observed weak diffusive gradients between subsoil and top soil, and net N2O production was maximum in the top soil. During the drying phase after a flood, diffusive gradients between subsoil and topsoil were more pronounced, and net N2O production in the subsoil increased. At all conditions, N2O efflux was more strongly correlated with N2O concentrations in the subsoil than those in the top soil. The complex interactions between soil moisture on one hand, and C and N substrate limitation on the other hand in determining N2O production at different soil depths will be discussed. Finally, the results will be put into the context of our earlier and ongoing studies that aim at elucidating the governing factors of spatial heterogeneity and dynamics of N2O emissions in floodplain soils.

  11. Differences in within- and between-person factor structure of positive and negative affect: analysis of two intensive measurement studies using multilevel structural equation modeling.

    PubMed

    Rush, Jonathan; Hofer, Scott M

    2014-06-01

    The Positive and Negative Affect Schedule (PANAS) is a widely used measure of emotional experience. The factor structure of the PANAS has been examined predominantly with cross-sectional designs, which fails to disaggregate within-person variation from between-person differences. There is still uncertainty as to the factor structure of positive and negative affect and whether they constitute 2 distinct independent factors. The present study examined the within-person and between-person factor structure of the PANAS in 2 independent samples that reported daily affect over 7 and 14 occasions, respectively. Results from multilevel confirmatory factor analyses revealed that a 2-factor structure at both the within-person and between-person levels, with correlated specific factors for overlapping items, provided good model fit. The best-fitting solution was one where within-person factors of positive and negative affect were inversely correlated, but between-person factors were independent. The structure was further validated through multilevel structural equation modeling examining the effects of cognitive interference, daily stress, physical symptoms, and physical activity on positive and negative affect factors.

  12. Ecology of invasive Melilotus alba on Alaskan glacial river floodplains

    Technology Transfer Automated Retrieval System (TEKTRAN)

    White sweetclover has recently invaded glacial river floodplains in Alaska. We sampled vegetation and measured environmental variables along transects located along the Nenana, Matanuska, and Stikine Rivers to describe plant communities and to determine the effects of white sweetclover on other plan...

  13. Hyporheic flow patterns in relation to large river floodplain attributes

    EPA Science Inventory

    Field-calibrated models of hyporheic flow have emphasized low-order headwater systems. In many cases, however, hyporheic flow in large lowland river floodplains may be an important contributor to ecosystem services such as maintenance of water quality and habitat. In this study, ...

  14. 78 FR 74009 - Floodplain Management and Protection of Wetlands; Correction

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-12-10

    ...-877-8339 (this is a toll-free number). SUPPLEMENTARY INFORMATION: On November 15, 2013 (78 FR 68719... this final rule by deleting Sec. 55.12(c)(12). In FR Doc. 2013-27427 appearing on page 68719 in the... URBAN DEVELOPMENT 24 CFR Parts 50, 55, and 58 RIN 2501-AD51 Floodplain Management and Protection...

  15. A New Hydrogeological Research Site in the Willamette River Floodplain

    EPA Science Inventory

    The Willamette River is a ninth-order tributary of the Columbia which passes through a productive and populous region in northwest Oregon. Where unconstrained by shoreline revetments, the floodplain of this river is a high-energy, dynamic system which supports a variety of ripari...

  16. Association Between Wetland Disturbance and Biological Attributes in Floodplain Wetlands

    EPA Science Inventory

    Our study explored the relationship between agricultural related disturbance and variation in wetland biota. Our results are intended to provide resource managers with information and tools to asess the condition of floodplain wetlands and make better decisions in terms of their...

  17. 78 FR 68719 - Floodplain Management and Protection of Wetlands

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-11-15

    ... under the 5-Step Process; for example, making hospitals and nursing homes, which are critical facilities... agencies (agencies) are charged by E.O. 11990, entitled Protection of Wetlands, dated May 24, 1977 (42 FR... (42 FR 26951), with incorporating floodplain management goals and wetland protection considerations...

  18. Reindeer grazing and climate change affects vegetation structure in the Swedish mountains

    NASA Astrophysics Data System (ADS)

    Vowles, Tage; Klemendtsen, Leif; Molau, Ulf; Björk, Robert G.

    2013-04-01

    There is substantial evidence indicating that arctic and alpine landscapes are undergoing distinct changes in plant community structure, presumably brought about by increasing temperatures and a prolonged snow-free season. However, recent studies have revealed that grazing by large herbivores can inhibit a climate-driven shrub expansion and plant community change. In northern Fennoscandia reindeer grazing has helped to shape the vegetation patterns since the last glacial period and is an important factor to consider in the understanding of how a changing climate will affect tundra ecosystems. This project examines the effects of reindeer grazing by revisiting fenced exclosures constructed in 1995. The exclosures were erected at four sites with different grazing intensities situated along the Scandinavian mountain range (from 61°30' to 68°30'). At three of the four sites, three fenced and three control (ambient conditions) plots (25×25 m each) were established in alpine tundra and in mountain birch forest, respectively. In the fourth site only tundra plots were established. In 2011/12 we used the same methodology as in the original 1995 inventories to determine the species composition, canopy height, and percentage cover of the shrub, field and bottom layers in the plots. In the birch forest, the tree layer was also estimated by determining species composition, cover, height, diameter, and individual density. Our results show that on the tundra, tall shrub cover has increased at our fenced-in plots over the past 16 years, whereas in ambient plots the response varies between sites. Low shrubs, too, have increased over time, yet showing no significant treatment effect. Graminoids, on the other hand have decreased overall, but significantly more in fenced-in plots. Furthermore, the shrub canopy height has increased significantly over time with implications for albedo and snow trapping effects. Bryophyte cover was significantly larger in ambient plots than in fenced

  19. Ord's kangaroo rats living in floodplain habitats: Factors contributing to habitat attraction

    USGS Publications Warehouse

    Miller, M.S.; Wilson, K.R.; Andersen, D.C.

    2003-01-01

    High densities of an aridland granivore, Ord's kangaroo rat (Dipodomys ordii), have been documented in floodplain habitats along the Yampa River in northwestern Colorado. Despite a high probability of inundation and attendant high mortality during the spring flood period, the habitat is consistently recolonized. To understand factors that potentially make riparian habitats attractive to D. ordii, we compared density and spatial pattern of seeds, density of a competitor (western harvester ant, Pogonomyrmex occidentalis), and digging energetics within floodplain habitats and between floodplain and adjacent upland habitats. Seed density within the floodplain was greatest in the topographically high (rarely flooded) floodplain and lowest immediately after a spring flood in the topographically low (frequently flooded) floodplain. Seed densities in adjacent upland habitat that never floods were higher than the lowest floodplain habitat. In the low floodplain prior to flooding, seeds had a clumped spatial pattern, which D. ordii is adept at exploiting; after spring flooding, a more random pattern resulted. Populations of the western harvester ant were low in the floodplain relative to the upland. Digging by D. ordii was energetically less expensive in floodplain areas than in upland areas. Despite the potential for mortality due to annual spring flooding, the combination of less competition from harvester ants and lower energetic costs of digging might promote the use of floodplain habitat by D. ordii.

  20. Deliberate self-harm in female patients with affective disorders: investigation of personality structure and affect regulation by means of operationalized psychodynamic diagnostics.

    PubMed

    Boeker, Heinz; Himmighoffen, Holger; Straub, Miriam; Schopper, Christian; Endrass, Jerome; Kuechenhoff, Bernhard; Weber, Silvan; Hell, Daniel

    2008-10-01

    This study investigated psychodynamically relevant dimensions in female depressive patients with and without deliberate self-harm (DSH). DSH is often observed in depressive patients and frequently shows a correlation with personality disorders. Forty female depressive patients with and without DSH were investigated after recovery from acute depressive pathology by means of "operationalized psychodynamic diagnostics" (OPD). Patients with DSH had a significantly lower level of integration in the OPD dimension "structure," and their "interpersonal relationships" showed dysfunctional interaction patterns. They also had a significantly higher rate of personality disorders. These results underline the significance of aspects of personality structure in female depressive patients with DSH, and enable a deeper understanding of their dysfunctional defense strategies, the connections with underlying disturbed affect regulation, and vicious circles in the therapeutic transference-countertransference relationship. OPD has been shown to be a useful tool for empirical research into therapeutically relevant dimensions of personality.

  1. Floodplain Vegetation Productivity and Carbon Cycle Dynamics of the Middle Fork Flathead River of Northwest Montana

    NASA Astrophysics Data System (ADS)

    Oakins, A. J.; Kimball, J. S.; Relyea, S.; Stanford, J. A.

    2005-05-01

    River floodplains are vital natural features that store floodwaters, improve water quality, provide habitat, and create recreational opportunities. Recent studies have shown that strong interactions among flooding, channel and sediment movement, vegetation, and groundwater create a dynamic shifting habitat mosaic that promotes biodiversity and complex food webs. Multiple physical and environmental processes interact within these systems to influence forest productivity, including water availability, nutrient supply, soil texture, and disturbance history. This study is designed to quantify the role of groundwater depth and meteorology in determining spatial and temporal patterns of net primary productivity (NPP) within the Nyack floodplain of the Middle Fork Flathead River, Northwestern Montana. We examine three intensive field sites composed of mature, mixed deciduous and evergreen conifer forest with varying hydrologic and vegetative characteristics. We use a modified Biome-BGC ecosystem process model with field-collected data (LAI, increment growth cores, groundwater depth, vegetation sap-flow, and local meteorology) to describe the effects of floodplain groundwater dynamics on vegetation community structure, and carbon/nitrogen cycling. Initial results indicate that conifers are more sensitive than deeper-rooted deciduous species to variability in groundwater depth and meteorological conditions. Forest productivity also shows a non-linear response to groundwater depth. Sites with intermediate groundwater depths (0.2-0.5m) allow vegetation to maintain connectivity to groundwater over longer periods during the growing season, are effectively uncoupled from atmospheric constraints on photosynthesis, and generally have greater productivity. Shallow groundwater sites (<0.2m) are less productive due to the indirect effects of reduced soil aerobic decomposition and reduced plant available nitrogen.

  2. Floodplain lakes and alluviation cycles of the lower Colorado River

    NASA Astrophysics Data System (ADS)

    Malmon, D.; Felger, T. J.; Howard, K. A.

    2007-05-01

    The broad valleys along the lower Colorado River contain numerous bodies of still water that provide critical habitat for bird, fish, and other species. This chain of floodplain lakes is an important part of the Pacific Flyway - the major north-south route of travel for migratory birds in the western Hemisphere - and is also used by many resident bird species. In addition, isolated floodplain lakes may provide the only viable habitat for endangered native fish such as the razorback sucker, vulnerable to predation by introduced species in the main stem of the Colorado River. Floodplain lakes typically occupy former channel courses of the river and formed as a result of river meandering or avulsion. Persistent fluvial sediment deposition (aggradation) creates conditions that favor rapid formation and destruction of floodplain lakes, while long term river downcutting (degradation) inhibits their formation and evolution. New radiocarbon dates from wood recovered from drill cores near Topock, AZ indicate that the river aggraded an average of 3 mm/yr in the middle and late Holocene. Aggradational conditions before Hoover Dam was built were associated with rapid channel shifting and frequent lake formation. Lakes had short life spans due to rapid infilling with fine-grained sediment during turbid floods on the unregulated Colorado River. The building of dams and of armored banks had a major impact on floodplain lakes, not only by drowning large portions of the valley beneath reservoirs, but by preventing new lake formation in some areas and accelerating it in others. GIS analyses of three sets of historical maps show that both the number and total area of isolated (i.e., not linked to the main channel by a surface water connection) lakes in the lower Colorado River valley increased between 1902 and the 1950s, and then decreased though the 1970s. River bed degradation below dams inhibits channel shifting and floodplain lake formation, and the capture of fines behind the

  3. Spatial dynamics of overbank sedimentation in floodplain systems

    USGS Publications Warehouse

    Pierce, A.R.; King, S.L.

    2008-01-01

    Floodplains provide valuable social and ecological functions, and understanding the rates and patterns of overbank sedimentation is critical for river basin management and rehabilitation. Channelization of alluvial systems throughout the world has altered hydrological and sedimentation processes within floodplain ecosystems. In the loess belt region of the Lower Mississippi Alluvial Valley of the United States, channelization, the geology of the region, and past land-use practices have resulted in the formation of dozens of valley plugs in stream channels and the formation of shoals at the confluence of stream systems. Valley plugs completely block stream channels with sediment and debris and can result in greater deposition rates on floodplain surfaces. Presently, however, information is lacking on the rates and variability of overbank sedimentation associated with valley plugs and shoals. We quantified deposition rates and textures in floodplains along channelized streams that contained valley plugs and shoals, in addition to floodplains occurring along an unchannelized stream, to improve our understanding of overbank sedimentation associated with channelized streams. Feldspar clay marker horizons and marker poles were used to measure floodplain deposition from 2002 to 2005 and data were analyzed with geospatial statistics to determine the spatial dynamics of sedimentation within the floodplains. Mean sediment deposition rates ranged from 0.09 to 0.67??cm/y at unchannelized sites, 0.16 to 2.27??cm/y at shoal sites, and 3.44 to 6.20??cm/y at valley plug sites. Valley plug sites had greater rates of deposition, and the deposited sediments contained more coarse sand material than either shoal or unchannelized sites. A total of 59 of 183 valley plug study plots had mean deposition rates > 5??cm/y. The geospatial analyses showed that the spatial dynamics of sedimentation can be influenced by the formation of valley plugs and shoals on channelized streams; however

  4. Influence of deposition of fine plant debris in river floodplain shrubs on flood flow conditions - The Warta River case study

    NASA Astrophysics Data System (ADS)

    Mazur, Robert; Kałuża, Tomasz; Chmist, Joanna; Walczak, Natalia; Laks, Ireneusz; Strzeliński, Paweł

    2016-08-01

    This paper presents problems caused by organic material transported by flowing water. This material is usually referred to as plant debris or organic debris. Its composition depends on the characteristic of the watercourse. For lowland rivers, the share of the so-called small organic matter in plant debris is considerable. This includes both various parts of water plants and floodplain vegetation (leaves, stems, blades of grass, twigs, etc.). During floods, larger woody debris poses a significant risk to bridges or other water engineering structures. It may cause river jams and may lead to damming of the flowing water. This, in turn, affects flood safety and increases flood risk in river valleys, both directly and indirectly. The importance of fine plant debris for the phenomenon being studied comes down to the hydrodynamic aspect (plant elements carried by water end up on trees and shrubs, increase hydraulic flow resistance and contribute to the nature of flow through vegetated areas changed from micro-to macro-structural). The key part of the research problem under analysis was to determine qualitative and quantitative debris parameters and to establish the relationship between the type of debris and the type of land use of river valleys (crop fields, meadows and forested river sections). Another problem was to identify parameters of plant debris for various flow conditions (e.g. for low, medium and flood flows). The research also included an analysis of the materials deposited on the structure of shrubs under flood flow conditions during the 2010 flood on the Warta River.

  5. Using geochemical indicators to distinguish high biogeochemical activity in floodplain soils and sediments.

    PubMed

    Kenwell, Amy; Navarre-Sitchler, Alexis; Prugue, Rodrigo; Spear, John R; Hering, Amanda S; Maxwell, Reed M; Carroll, Rosemary W H; Williams, Kenneth H

    2016-09-01

    A better understanding of how microbial communities interact with their surroundings in physically and chemically heterogeneous subsurface environments will lead to improved quantification of biogeochemical reactions and associated nutrient cycling. This study develops a methodology to predict potential elevated rates of biogeochemical activity (microbial "hotspots") in subsurface environments by correlating microbial DNA and aspects of the community structure with the spatial distribution of geochemical indicators in subsurface sediments. Multiple linear regression models of simulated precipitation leachate, HCl and hydroxylamine extractable iron and manganese, total organic carbon (TOC), and microbial community structure were used to identify sample characteristics indicative of biogeochemical hotspots within fluvially-derived aquifer sediments and overlying soils. The method has been applied to (a) alluvial materials collected at a former uranium mill site near Rifle, Colorado and (b) relatively undisturbed floodplain deposits (soils and sediments) collected along the East River near Crested Butte, Colorado. At Rifle, 16 alluvial samples were taken from 8 sediment cores, and at the East River, 46 soil/sediment samples were collected across and perpendicular to 3 active meanders and an oxbow meander. Regression models using TOC and TOC combined with extractable iron and manganese results were determined to be the best fitting statistical models of microbial DNA (via 16S rRNA gene analysis). Fitting these models to observations in both contaminated and natural floodplain deposits, and their associated alluvial aquifers, demonstrates the broad applicability of the geochemical indicator based approach. PMID:27145490

  6. Where the woodland ends: How edges affect landscape structure and physiological responses of Quercus agrifolia

    NASA Astrophysics Data System (ADS)

    de Chant, Timothy Paul

    Forests and woodlands are integral parts of ecosystems across the globe, but they are threatened by a variety of factors, including urbanization and introduced forest pathogens. These two forces are fundamentally altering ecosystems, both by removing forest cover and reshaping landscapes. Comprehending how these two processes have changed forest ecosystems is an important step toward understanding how the affected systems will function in the future. I investigated the range of edge effects that result from disturbance brought about by forest pathogens and urbanization in two coastal oak woodlands in Marin County, California. Oak woodlands are a dynamic part of California's landscape, reacting to changes in their biotic and abiotic environments across a range of spatial and temporal scales. Sudden Oak Death, caused by the introduced forest pathogen Phytophthora ramorum, has led to widespread mortality of many tree species in California's oak woodlands. I investigated how the remaining trees respond to such rapid changes in canopy structure (Chapter 2), and my results revealed a forest canopy quick to respond to the new openings. Urbanization, another disturbance regime, operates on a longer time scale. Immediately following urban development, forest edges are strikingly linear, but both forest processes and homeowner actions likely work in concert to disrupt the straight edge (Chapter 3). Forest edges grew more sinuous within 14 years of the initial disturbance, and continued to do so for the remainder of the study, another 21 years. Individual Quercus agrifolia trees also respond to urban edges decades after disturbance (Chapter 4), and their reaction is reflected in declining stable carbon isotope values (delta13C). This change suggests trees may have increased their stomatal conductance in response to greater water availability, reduced their photosynthetic rate as a result of stress, or some combination of both. Edges have far reaching and long lasting effects

  7. Murine startle mutant Nmf11 affects the structural stability of the glycine receptor and increases deactivation

    PubMed Central

    Wilkins, Megan E.; Caley, Alex; Gielen, Marc C.; Harvey, Robert J.

    2016-01-01

    Key points Hyperekplexia or startle disease is a serious neurological condition affecting newborn children and usually involves dysfunctional glycinergic neurotransmission.Glycine receptors (GlyRs) are major mediators of inhibition in the spinal cord and brainstem.A missense mutation, replacing asparagine (N) with lysine (K), at position 46 in the GlyR α1 subunit induced hyperekplexia following a reduction in the potency of the transmitter glycine; this resulted from a rapid deactivation of the agonist current at mutant GlyRs.These effects of N46K were rescued by mutating a juxtaposed residue, N61 on binding Loop D, suggesting these two asparagines may interact.Asparagine 46 is considered to be important for the structural stability of the subunit interface and glycine binding site, and its mutation represents a new mechanism by which GlyR dysfunction induces startle disease. Abstract Dysfunctional glycinergic inhibitory transmission underlies the debilitating neurological condition, hyperekplexia, which is characterised by exaggerated startle reflexes, muscle hypertonia and apnoea. Here we investigated the N46K missense mutation in the GlyR α1 subunit gene found in the ethylnitrosourea (ENU) murine mutant, Nmf11, which causes reduced body size, evoked tremor, seizures, muscle stiffness, and morbidity by postnatal day 21. Introducing the N46K mutation into recombinant GlyR α1 homomeric receptors, expressed in HEK cells, reduced the potencies of glycine, β‐alanine and taurine by 9‐, 6‐ and 3‐fold respectively, and that of the competitive antagonist strychnine by 15‐fold. Replacing N46 with hydrophobic, charged or polar residues revealed that the amide moiety of asparagine was crucial for GlyR activation. Co‐mutating N61, located on a neighbouring β loop to N46, rescued the wild‐type phenotype depending on the amino acid charge. Single‐channel recording identified that burst length for the N46K mutant was reduced and fast agonist application

  8. Nitrogen sources, transport and processing in peri-urban floodplains.

    PubMed

    Gooddy, D C; Macdonald, D M J; Lapworth, D J; Bennett, S A; Griffiths, K J

    2014-10-01

    Peri-urban floodplains are an important interface between developed land and the aquatic environment and may act as a source or sink for contaminants moving from urban areas towards surface water courses. With increasing pressure from urban development the functioning of floodplains is coming under greater scrutiny. A number of peri-urban sites have been found to be populated with legacy landfills which could potentially cause pollution of adjacent river bodies. Here, a peri-urban floodplain adjoining the city of Oxford, UK, with the River Thames has been investigated over a period of three years through repeated sampling of groundwaters from existing and specially constructed piezometers. A nearby landfill has been found to have imprinted a strong signal on the groundwater with particularly high concentrations of ammonium and generally low concentrations of nitrate and dissolved oxygen. An intensive study of nitrogen dynamics through the use of N-species chemistry, nitrogen isotopes and dissolved nitrous oxide reveals that there is little or no denitrification in the majority of the main landfill plume, and neither is the ammonium significantly retarded by sorption to the aquifer sediments. A simple model has determined the flux of total nitrogen and ammonium from the landfill, through the floodplain and into the river. Over an 8 km reach of the river, which has a number of other legacy landfills, it is estimated that 27.5 tonnes of ammonium may be delivered to the river annually. Although this is a relatively small contribution to the total river nitrogen, it may represent up to 15% of the ammonium loading at the study site and over the length of the reach could increase in-stream concentrations by nearly 40%. Catchment management plans that encompass floodplains in the peri-urban environment need to take into account the likely risk to groundwater and surface water quality that these environments pose.

  9. Do Vermont's Floodplains Constitute an Important Source of Labile Carbon?

    NASA Astrophysics Data System (ADS)

    Perdrial, J. N.; Dolan, A.; Kemsley, M.

    2014-12-01

    Floodplains are extremely heterogeneous landscapes with respect to soil and sediment composition and can present an important source of carbon (C) during floods. For example, stream bank soils and sediments are zones of active erosion and deposition of sediment associated C. Due to the presence of plants, riparian soils contain high amounts of C that is exchanged between stream waters and banks. Abandoned channels and meander wetlands that remain hydrologically connected to the main channel contain high amounts of organic matter that can be flushed into the stream during high discharge. This heterogeneity, result of floodplain geomorphology, land cover and use, can profoundly impact the amount and type of dissolved organic matter (DOM) introduced into streams. In order to assess DOM characteristics leached from heterogeneous floodplain soils, aqueous soil extracts were performed on soil samples representative of different land covers (n=20) at four depths. Extracts were analyzed for dissolved organic C and total dissolved nitrogen with a Shimadzu C analyzer. Colored dissolved organic matter characteristics was measured with the Aqualog Fluorescence Spectrometer and quantified with parallel factor analysis (PARAFAC). Preliminary data from three floodplains in Vermont (Connecticut, Missisquoi and Mad River) show a 3D variability of longitudinal, lateral, and vertical extents on water-extractable, mobile C. Dissolved organic carbon concentrations in meander swamp samples were found up to 9 times higher than in those of soils from agricultural field indicative of an important C source. Although C concentrations in adjacent fields were low, high abundance of labile C (indicated by tryptophan-like fluorescence) in water extracts from fields indicates recent biological production of C. This labile C is easily processed by microbes and transformed to the greenhouse gas CO2. These results provide important information on the contribution and lability of different floodplain

  10. Carbon dioxide and methane exports from a southeastern floodplain swamp

    SciTech Connect

    Pulliam, W.M. )

    1993-02-01

    Patterns and rates of generation of CO[sub 2] and CH[sub 4] by aerobic and anaerobic soil respiration are a significant gap in knowledge of floodplain carbon dynamics. Gaseous and hydrologic exports of CO[sub 2] and CH[sub 4] from the forested floodplain of the Ogeechee River in Georgia, US, were studied from July 1987 to September 1989. CO[sub 2] emissions were highly seasonal, with largest rates during summer, and were strongly correlated with soil temperatures. Annual total CO[sub 2] emissions were similar in both years of the study, and averaged 919 g/m[sup 2]. The contribution of live root respiration to this total was estimated with in situ incubations of attached roots excavated from the soil. Over 55% of the total CO[sub 2] flux appeared to arise from live roots rather than mineralization of soil organic matter. Significant atmospheric CH[sub 4] fluxes were found only at flooded sites. CH[sub 4] emissions were highly variable, with high rates of release occurring irregularly during the warmer months. This effect is hypothesized to represent an interaction of the rates of oxygen consumption and replenishment in the soil. Over 90% of the total floodplain CH[sub 4] emissions came from the 30% of the floodplain that was most frequently inundated. Roughly half of the CH[sub 4] that entered the water column was consumed without reaching the atmosphere. Hydrologic exports of CO[sub 2] and CH[sub 4] via surface and groundwater were small, representing [approx]1-2% of total export for both species, and were much less important than fluvial exports of organic carbon. Overall, floodplain detrital carbon processing was dominated by aerobic respiration and gaseous CO[sub 2] export, although methanogenesis did constitute up to 20% of total soil respiration at some sites. 94 refs., 17 figs., 10 tabs.

  11. Nitrogen sources, transport and processing in peri-urban floodplains.

    PubMed

    Gooddy, D C; Macdonald, D M J; Lapworth, D J; Bennett, S A; Griffiths, K J

    2014-10-01

    Peri-urban floodplains are an important interface between developed land and the aquatic environment and may act as a source or sink for contaminants moving from urban areas towards surface water courses. With increasing pressure from urban development the functioning of floodplains is coming under greater scrutiny. A number of peri-urban sites have been found to be populated with legacy landfills which could potentially cause pollution of adjacent river bodies. Here, a peri-urban floodplain adjoining the city of Oxford, UK, with the River Thames has been investigated over a period of three years through repeated sampling of groundwaters from existing and specially constructed piezometers. A nearby landfill has been found to have imprinted a strong signal on the groundwater with particularly high concentrations of ammonium and generally low concentrations of nitrate and dissolved oxygen. An intensive study of nitrogen dynamics through the use of N-species chemistry, nitrogen isotopes and dissolved nitrous oxide reveals that there is little or no denitrification in the majority of the main landfill plume, and neither is the ammonium significantly retarded by sorption to the aquifer sediments. A simple model has determined the flux of total nitrogen and ammonium from the landfill, through the floodplain and into the river. Over an 8 km reach of the river, which has a number of other legacy landfills, it is estimated that 27.5 tonnes of ammonium may be delivered to the river annually. Although this is a relatively small contribution to the total river nitrogen, it may represent up to 15% of the ammonium loading at the study site and over the length of the reach could increase in-stream concentrations by nearly 40%. Catchment management plans that encompass floodplains in the peri-urban environment need to take into account the likely risk to groundwater and surface water quality that these environments pose. PMID:25029502

  12. Can intra-aggregate pore structures affect the aggregate's effectiveness in protecting carbon?

    SciTech Connect

    Ananyeva, K; Wang, W; Smucker, A J.M.; Rivers, M L; Kravchenko, A N

    2012-11-15

    Aggregates are known to provide physical protection to soil organic matter shielding it from rapid decomposition. Spatial arrangement and size distribution of intra-aggregate pores play an important role in this process. This study examined relationships between intra-aggregate pores measured using X-ray computed micro-tomography images and concentrations of total C in 4–6 mm macro-aggregates from two contrasting land use and management practices, namely, conventionally tilled and managed row crop agricultural system (CT) and native succession vegetation converted from tilled agricultural land in 1989 (NS). Previous analyses of these aggregates indicated that small (<15 μm) and large (>100 μm) pores prevail in NS aggregates while medium (30–90 μm) pores are more abundant in CT aggregates (Kravchenko et al., 2011; Wang et al., 2012). We hypothesized that these differences in pore size distributions affect the ability of macro-aggregates to protect C. The results of this study supported this hypothesis. Consistent with greater heterogeneity of pore distributions within NS aggregates we observed higher total C and greater intra-aggregate C variability in NS as compared with CT aggregates. Total C concentrations and intra-aggregate C standard deviations were negatively correlated with fractions of medium sized pores, indicating that presence of such pores was associated with lower but more homogeneously distributed total C. While total C was positively correlated with presence of small and large pores. The results suggest that because of their pore structure NS macro-aggregates provide more effective physical protection to C than CT aggregates.

  13. Habitat associations, reproduction and diet of the Guinean tilapia Tilapia guineensis of the Gambia River floodplains.

    PubMed

    Louca, V; Lindsay, S W; Piyapong, C; Lucas, M C

    2010-06-01

    The ecology of the Guinean tilapia Tilapia guineensis a dominant species of the lower Gambia River floodplains and an important food source in parts of West Africa was studied to better understand the threat posed from construction of a barrage across the river. The catch per unit effort (CPUE) of T. guineensis was positively associated with conductivity and dissolved oxygen and negatively associated with water depth and the % vegetation cover. Diet studies indicated that the T. guineensis is primarily an iliophage. The peak of reproduction was at the beginning of the rainy season. CPUE peaked in May, just before the first rains, and subsequently declined, probably reflecting movement into newly flooded habitat. Median size at maturity was 11.6 cm total length, L(T), for females and 12.5 cm L(T) for males. L(T)-frequency analysis indicated several juvenile cohorts as well as very young fish on the floodplains each month, suggesting continuation of reproduction throughout the rainy season. The impending construction of a hydroelectric dam on the Gambia River is likely to affect T. guineensis negatively through anticipated changes in the hydrology of the river.

  14. Habitat associations, reproduction and diet of the Guinean tilapia Tilapia guineensis of the Gambia River floodplains.

    PubMed

    Louca, V; Lindsay, S W; Piyapong, C; Lucas, M C

    2010-06-01

    The ecology of the Guinean tilapia Tilapia guineensis a dominant species of the lower Gambia River floodplains and an important food source in parts of West Africa was studied to better understand the threat posed from construction of a barrage across the river. The catch per unit effort (CPUE) of T. guineensis was positively associated with conductivity and dissolved oxygen and negatively associated with water depth and the % vegetation cover. Diet studies indicated that the T. guineensis is primarily an iliophage. The peak of reproduction was at the beginning of the rainy season. CPUE peaked in May, just before the first rains, and subsequently declined, probably reflecting movement into newly flooded habitat. Median size at maturity was 11.6 cm total length, L(T), for females and 12.5 cm L(T) for males. L(T)-frequency analysis indicated several juvenile cohorts as well as very young fish on the floodplains each month, suggesting continuation of reproduction throughout the rainy season. The impending construction of a hydroelectric dam on the Gambia River is likely to affect T. guineensis negatively through anticipated changes in the hydrology of the river. PMID:20557603

  15. Fluvial Landforms and Landscape Transformations on a Large River Floodplain: Willamette River, Oregon, USA

    NASA Astrophysics Data System (ADS)

    Wallick, R.

    2015-12-01

    Recent detailed mapping of the Willamette River floodplain in northwestern Oregon reveals insights into the floodplain landforms, their formative processes, and historical landscape transformations. Hierarchical mapping classification based mainly upon lidar topography, supplemented by aerial photographs, historical channel and soil maps, and targeted coring of floodplain soils, was carried out for 200 km of the mainstem Willamette River floodplain above Willamette Falls where floodplain landforms mainly reflect fluvial and anthropogenic influences. Stark differences in the character and distribution of floodplain landforms and their underlying stratigraphy give rise to three distinct process regimes along the fluvial portion of the Willamette River. Floodplain surfaces along 60 km of the Upper Willamette River floodplain generally rise 1-2 m above the low-flow water surface and are bisected by complex assemblage of overflow channels and large-amplitude abandoned bends formed by avulsions along this historically multi-thread anastomosing reach. Downstream, the 90 km-long Middle Willamette River between Corvallis and Newburg Pool becomes increasingly entrenched within its floodplain, with floodplains gradually rising up to 8 m above the low flow water surface. These floodplain surfaces are dominated by ridge and swale topography with occasional floodbasins reflecting gradual meander migration and floodplain aggradation. The 50 km-long Newberg Pool is entrenched and confined by Pleistocene Missoula flood deposits and bedrock valley walls. This low-gradient reach extends to the lip of the15-m high Willamette Falls. Historical declines in flood magnitude, bed-material supply, large wood, and bank erodibility result in a more stable modern-day floodplain with narrower active-channel corridor flanked by relict landforms formed by historical flow and sediment regime. Landscape transformations vary across the three process regimes but are greatest along Upper Willamette

  16. The role of floodplain restoration in mitigating flood risk, Lower Missouri River, USA

    USGS Publications Warehouse

    Jacobson, Robert B.; Lindner, Garth; Bitner, Chance

    2009-01-01

    Recent extreme floods on the Lower Missouri River have reinvigorated public policy debate about the potential role of floodplain restoration in decreasing costs of floods and possibly increasing other ecosystem service benefits. The first step to addressing the benefits of floodplain restoration is to understand the interactions of flow, floodplain morphology, and land cover that together determine the biophysical capacity of the floodplain. In this article we address interactions between ecological restoration of floodplains and flood-risk reduction at 3 scales. At the scale of the Lower Missouri River corridor (1300 km) floodplain elevation datasets and flow models provide first-order calculations of the potential for Missouri River floodplains to store floods of varying magnitude and duration. At this same scale assessment of floodplain sand deposition from the 2011 Missouri River flood indicates the magnitude of flood damage that could potentially be limited by floodplain restoration. At the segment scale (85 km), 1-dimensional hydraulic modeling predicts substantial stage reductions with increasing area of floodplain restoration; mean stage reductions range from 0.12 to 0.66 m. This analysis also indicates that channel widening may contribute substantially to stage reductions as part of a comprehensive strategy to restore floodplain and channel habitats. Unsteady 1-dimensional flow modeling of restoration scenarios at this scale indicates that attenuation of peak discharges of an observed hydrograph from May 2007, of similar magnitude to a 10 % annual exceedance probability flood, would be minimal, ranging from 0.04 % (with 16 % floodplain restoration) to 0.13 % (with 100 % restoration). At the reach scale (15–20 km) 2-dimensional hydraulic models of alternative levee setbacks and floodplain roughness indicate complex processes and patterns of flooding including substantial variation in stage reductions across floodplains depending on topographic complexity

  17. Seasonal dynamics of the fish assemblage in a floodplain lake at the confluence of the Negro and Amazon Rivers.

    PubMed

    Röpke, C P; Amadio, S A; Winemiller, K O; Zuanon, J

    2016-07-01

    The temporal effect of discharge and limnology on fish composition and species diversity in a floodplain lake at the confluence of the Amazon and Negro Rivers was evaluated. Species richness, abundance and assemblage composition were strongly influenced by seasonal discharge of the Amazon and Negro Rivers, which affects lateral connectivity, water conductivity and temperature. As a consequence, temporal β-diversity was high in the lake and the assemblage was dominated by seasonally transient species. Relatively large species known to feed on resources within the floodplain were captured almost exclusively during the flood period. During the dry season, the assemblage was dominated by fishes adapted to harsh conditions of high temperature and low dissolved oxygen concentrations. An open system with high spatial and temporal heterogeneity created by the meeting of two large rivers with different water chemistry, Lago Catalão has a dynamic fish assemblage. Given its high temporal β-diversity and abundance of fishes, many of great importance in local fisheries, Lago Catalão and other floodplain lakes in this region merit special attention for conservation. PMID:26563716

  18. Seasonal dynamics of the fish assemblage in a floodplain lake at the confluence of the Negro and Amazon Rivers.

    PubMed

    Röpke, C P; Amadio, S A; Winemiller, K O; Zuanon, J

    2016-07-01

    The temporal effect of discharge and limnology on fish composition and species diversity in a floodplain lake at the confluence of the Amazon and Negro Rivers was evaluated. Species richness, abundance and assemblage composition were strongly influenced by seasonal discharge of the Amazon and Negro Rivers, which affects lateral connectivity, water conductivity and temperature. As a consequence, temporal β-diversity was high in the lake and the assemblage was dominated by seasonally transient species. Relatively large species known to feed on resources within the floodplain were captured almost exclusively during the flood period. During the dry season, the assemblage was dominated by fishes adapted to harsh conditions of high temperature and low dissolved oxygen concentrations. An open system with high spatial and temporal heterogeneity created by the meeting of two large rivers with different water chemistry, Lago Catalão has a dynamic fish assemblage. Given its high temporal β-diversity and abundance of fishes, many of great importance in local fisheries, Lago Catalão and other floodplain lakes in this region merit special attention for conservation.

  19. Consistent trophic patterns among fishes in lagoon and channel habitats of a tropical floodplain river: Evidence from stable isotopes

    NASA Astrophysics Data System (ADS)

    Roach, Katherine A.; Winemiller, Kirk O.; Layman, Craig A.; Zeug, Steven C.

    2009-07-01

    The relationship between food web dynamics and hydrological connectivity in rivers should be strongly influenced by annual flood pulses that affect primary production dynamics and movement of organic matter and consumer taxa. We sampled basal production sources and fishes from connected lagoons and the main channel of a low-gradient, floodplain river within the Orinoco River Basin in Venezuela. Stable isotope analysis was used to model the contribution of four basal production sources to fishes, and to examine patterns of mean trophic position during the falling-water period of the annual flood cycle. IsoSource, a multi-source mixing model, indicated that proportional contributions from production sources to fish assemblages were similar in lagoons and the main channel. Although distributions differed, the means for trophic positions of fish assemblages as well as individual species were similar between the two habitats. These findings contradict recent food web studies conducted in temperate floodplain rivers that described significant differences in trophic positions of fishes from slackwater and floodplain versus main channel habitats. Low between-habitat trophic variation in this tropical river probably results from an extended annual flood pulse (ca. 5 mo.) that allows mixing of sestonic and allochthonous basal production sources and extensive lateral movements of fishes throughout the riverscape.

  20. Strategic floodplain reconnection for the Lower Tisza River, Hungary: Opportunities for flood-height reduction and floodplain-wetland reconnection

    NASA Astrophysics Data System (ADS)

    Guida, Ross J.; Swanson, Taylor L.; Remo, Jonathan W. F.; Kiss, Timea

    2015-02-01

    During the late 19th Century, the Tisza River's vast floodplain-wetland system was largely disconnected by levees, facilitating "reclamation" for agriculture and resulting in an estimated loss of over 90% of historical wetlands. While levees have been successful in preventing catastrophic flooding for a century, Lower Tisza flood stage records have been set repeatedly during the last 15 years. The decrease in the Tisza's current floodway carrying capacity has reduced the flood-protection level of the Tisza's aging levee system. Recently in Hungary, "Room for the River" policies have gained more prominence. To explore the possibilities of a room for the river approach along the Lower Tisza, we assess eight potential floodplain-reconnection scenarios between Csongrád, Hungary and the Hungary-Serbia border. A novel framework using hydrodynamic and geospatial modeling was used to perform planning-level evaluations of the tradeoffs between floodplain-reconnection scenarios and enhancement of the existing levee system. The scenarios evaluated include levee removal and levee setbacks to strategically reconnect significant historical wetlands while reducing flood levels. Scenario costs and human population impacts are also assessed. Impacts of reconnecting the Lower Tisza floodplain are compared to heightening levees, the prevailing strategy over the previous century. From a purely construction-cost perspective, heightening Lower Tisza levees is potentially the most cost-effective and politically expedient solution (i.e., impacts the least number of people). However, levee-heightening does not solve the long-term problem of reduced flood conveyance, which has been attributed to aggradation and increased floodplain roughness, nor does it result in wetland reconnection or enhancement of other floodplain ecosystem services. The suite of reconnection options we evaluate provides engineers, planners, and decision makers a framework from which they can further evaluate

  1. Comparing riparian forest processes on large rivers to inform floodplain management and restoration

    NASA Astrophysics Data System (ADS)

    Stella, J. C.; Piegay, H.; Gruel, C.; Riddle, J.; Raepple, B.

    2014-12-01

    In populous, water-limited regions, humans have profoundly altered the river and floodplain environment to satisfy society's demands for water, power, navigation and safety. River management also profoundly alters riparian forests, which respond to changes in disturbance regimes and sediment dynamics. In this study, we compare forest and floodplain development along two of the most heavily modified rivers in mediterranean-climate regions, the middle Sacramento (California, USA) and the lower Rhône (SE France). The Sacramento was dammed in 1942 and is now managed for irrigation, hydropower and flood control. The Rhône channel was engineered for navigation prior to 1900, and since then has been dammed and diverted at 18 sites for hydropower and irrigation. We conducted extensive forest inventories and sampled fine sediment depth in regulated reaches within both systems, and compared pre- versus post-dam patterns of deposition and linked forest development. We sampled 441 plots (500 m2 each) along 160 km of the Sacramento, and 88 plots (1256 m2) stratified by management epoch (pre-river engineering, pre-dam, post-dam) along 160 km of the Rhône. On the Sacramento, forest composition showed shifting tree species dominance across a chronosequence of aerial photo dates over 110 years. The transition from willow to cottonwood (Populus) occurred within 20 years, and the transition to mixed forest started after 50-60 years. On the Rhône, the pre- versus post-dam surfaces at each site had distinct geomorphic and floristic characteristics. Floodplain areas that emerged and were forested in the pre-dam period were at higher elevation, and supported 30-50% more basal area, 20-30% more vine cover, and greater plant species diversity than those that emerged in the post-dam period. The shift from Populus dominance to other species began approximately a decade earlier on the Rhône compared to the Sacramento. Both rivers showed a strong understory presence on young floodplains

  2. Torrent floodplain mapping and torrent flood control in Serbia in the conditions of economic crisis

    NASA Astrophysics Data System (ADS)

    Gavrilovic, Z.; Stefanovic, M.

    2009-04-01

    Serbia is a country that is endangered by flooding of the largest European river, the Danube and its largest tributaries, as well as by countless torrents. During the 19th and 20th centuries, an imposing scope of protection structures was constructed. The existence of the protection system created the conviction that flood protection was achieved and that it should only be complemented on a great number of unregulated torrents. Such an opinion and practice are possible only in the countries with powerful economies. However, for almost two decades, Serbia has been going through the conditions of economic crisis. The floods which occurred in Serbia during that period pointed to the problem of maintenance of the existing protection system and to the impossibility of building the new projects. Floodplain mapping, although prescribed by the Law, was postponed because of the high price of the classical geodetic surveying. The postponing of this activity, in the conditions of a stable and good economic situation, was explained by the achieved flood protection on large rivers and by low probability that the system could fail. On the other hand, small torrents were partly regulated in the zones of roads and towns, so in this case also it was thought that the protection was accomplished. It was overlooked that the majority of torrents in Serbia was not regulated by any protection system. Urbanisation was progressing unrestrainedly. The State could not afford the construction of the necessary protection system, so numerous settlements remained at risk, without any protection. Floods did not forgive and forget any mistakes and the awareness of the necessity of collecting the data on floodplains and protection against floods became an indispensable task, but in the conditions of economic crisis, difficult to realise. For this reason, a rational method of floodplain mapping was searched, as well as the method of reducing the damage caused by floods, but not requiring high

  3. Assessing floodplain restoration success using soil morphology indicators

    NASA Astrophysics Data System (ADS)

    Guenat, Claire; Fournier, Bertrand; Bullinger-Weber, Géraldine; Grin, Karin; Pfund, Simona; Mitchell, Edward

    2010-05-01

    Floodplains are complex ecological systems that fulfil different ecological, economic and social functions related to physical, chemical, and biological processes. The fluvial dynamics of most rivers in industrialized countries have been altered to such an extent that floodplains are now one of the most threatened ecosystems worldwide. This adverse impact has been widely recognized and, nowadays, extensive attempts are underway to return rivers to more natural conditions and restore their ecological quality and essential ecosystem functions. As a consequence, the number of restoration projects worldwide is rapidly increasing. However, despite an estimated global cost of more than 1 billion dollars annually, there is a crucial lack of monitoring and quantitative evaluations. Indeed, most projects are never monitored post-restoration (NRC 1992). In Switzerland, only 35% of the projects include a monitoring program mainly based on flora and fauna (BAFU). The design, selection and optimization of indicators for project monitoring are of major importance for sustainable management of riverine ecosystems. However, despite the growing body of literature on potential indicators and criteria for assessing the success of restoration projects no standardised or generally applicable method exists. Furthermore, soils are rarely considered among the possible indicators despite their crucial roles in ecosystems such as decomposition, supplying resources (habitats, gene pool, biomass, and raw materials), and environmental interactions (storage, filtering, transformation). We therefore hypothesized that soils may constitute an appropriate synthetic and functional indicator for the evaluation of river restoration success, especially in the framework of river widening aiming to increase the terrestrial biodiversity. In agreement with the current concepts of river restoration, we propose an assessment tool for floodplain restoration based on three soil morphology criteria (soil

  4. 76 FR 35912 - Business Jet Aircraft Industry: Structure and Factors Affecting Competitiveness; Institution of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-06-20

    ..., and business innovation; 4. Information on government policies and programs that focus on or otherwise involve the industry, including policies and programs affecting financing, aircraft research and... From the Federal Register Online via the Government Publishing Office INTERNATIONAL...

  5. The Impact of the School-Based Psychosocial Structured Activities (PSSA) Program on Conflict-Affected Children in Northern Uganda

    ERIC Educational Resources Information Center

    Ager, Alastair; Akesson, Bree; Stark, Lindsay; Flouri, Eirini; Okot, Braxton; McCollister, Faith; Boothby, Neil

    2011-01-01

    Background: Children in northern Uganda have undergone significant psychosocial stress during the region's lengthy conflict. A Psychosocial Structured Activities (PSSA) program was implemented in 21 schools identified as amongst those most severely affected by conflict-induced displacement across Gulu and Amuru Districts. The PSSA intervention…

  6. Body Dissatisfaction and Eating Disturbances in Early Adolescence: A Structural Modeling Investigation Examining Negative Affect and Peer Factors

    ERIC Educational Resources Information Center

    Hutchinson, Delyse M.; Rapee, Ronald M.; Taylor, Alan

    2010-01-01

    This study tested five proposed models of the relationship of negative affect and peer factors in early adolescent body dissatisfaction, dieting, and bulimic behaviors. A large community sample of girls in early adolescence was assessed via questionnaire (X[overbar] age = 12.3 years). Structural equation modeling (SEM) indicated that negative…

  7. Effect of Teacher Structure, Teacher Affect, Cognitive Level of Questions, Group Size and Student Social Status on Reading Achievement.

    ERIC Educational Resources Information Center

    Creamer, Mary; Lorentz, Jeffrey L.

    The effects of student socioeconomic status (SES) and four teacher behaviors--teacher structure, teacher affect, cognitive level of questions, and group size--on student reading achievement were analyzed. Subjects were 36 fifth and sixth grade classroom teachers and their 820 students. Data were collected with the Reading Comprehension Subtest…

  8. Floodplains within reservoirs promote earlier spawning of white crappies Pomoxis annularis

    USGS Publications Warehouse

    Miranda, Leandro E.; Dagel, Jonah D.; Kaczka, Levi J.; Mower, Ethan; Wigen, S. L.

    2015-01-01

    Reservoirs impounded over floodplain rivers are unique because they may include within their upper reaches extensive shallow water stored over preexistent floodplains. Because of their relatively flat topography and riverine origin, floodplains in the upper reaches of reservoirs provide broad expanses of vegetation within a narrow range of reservoir water levels. Elsewhere in the reservoir, topography creates a band of shallow water along the contour of the reservoir where vegetation often does not grow. Thus, as water levels rise, floodplains may be the first vegetated habitats inundated within the reservoir. We hypothesized that shallow water in reservoir floodplains would attract spawning white crappies Pomoxis annularis earlier than reservoir embayments. Crappie relative abundance over five years in floodplains and embayments of four reservoirs increased as spawning season approached, peaked, and decreased as fish exited shallow water. Relative abundance peaked earlier in floodplains than embayments, and the difference was magnified with higher water levels. Early access to suitable spawning habitat promotes earlier spawning and may increase population fitness. Recognition of the importance of reservoir floodplains, an understanding of how reservoir water levels can be managed to provide timely connectivity to floodplains, and conservation of reservoir floodplains may be focal points of environmental management in reservoirs.

  9. Fish mediate high food web connectivity in the lower reaches of a tropical floodplain river.

    PubMed

    Jardine, Timothy D; Pusey, Bradley J; Hamilton, Stephen K; Pettit, Neil E; Davies, Peter M; Douglas, Michael M; Sinnamon, Vivian; Halliday, Ian A; Bunn, Stuart E

    2012-03-01

    High levels of hydrological connectivity during seasonal flooding provide significant opportunities for movements of fish between rivers and their floodplains, estuaries and the sea, possibly mediating food web subsidies among habitats. To determine the degree of utilisation of food sources from different habitats in a tropical river with a short floodplain inundation duration (~2 months), stable isotope ratios in fishes and their available food were measured from three habitats (inundated floodplain, dry season freshwater, coastal marine) in the lower reaches of the Mitchell River, Queensland (Australia). Floodplain food sources constituted the majority of the diet of large-bodied fishes (barramundi Lates calcarifer, catfish Neoarius graeffei) captured on the floodplain in the wet season and for gonadal tissues of a common herbivorous fish (gizzard shad Nematalosa come), the latter suggesting that critical reproductive phases are fuelled by floodplain production. Floodplain food sources also subsidised barramundi from the recreational fishery in adjacent coastal and estuarine areas, and the broader fish community from a freshwater lagoon. These findings highlight the importance of the floodplain in supporting the production of large fishes in spite of the episodic nature and relatively short duration of inundation compared to large river floodplains of humid tropical regions. They also illustrate the high degree of food web connectivity mediated by mobile fish in this system in the absence of human modification, and point to the potential consequences of water resource development that may reduce or eliminate hydrological connectivity between the river and its floodplain.

  10. Properties of a 5500-year-old flood-plain in the Loup River Basin, Nebraska

    NASA Astrophysics Data System (ADS)

    May, David W.

    2003-12-01

    Flood-plain aggradation within the Loup River Basin of central Nebraska was episodic and alternated with incision throughout much of the Holocene. A widespread episode of flood-plain stability, however, occurred about 5700-5100 cal. year BP. The purpose of this paper is to describe the properties of this buried flood-plain at six sites in the basin, to consider why the properties of the buried flood-plain vary from site to site, and to evaluate possible reasons why the Loup River flood-plains stabilized 5500 years ago. Episodic valley-bottom aggradation was common during flood-plain formation at five of the six sites. The radiocarbon ages, particle-size data, and organic-carbon data for the buried flood-plain reveal that valley-bottom aggradation generally slowed between about 5700 and 5100 cal. year BP. Erratic down-profile changes in percentages of sand, clay, and organic matter indicate flood-plain sedimentation and soil formation were often episodic. Sand and clay rarely show a steady fining-upward trend. Organic matter fluctuates with depth; at some sites multiple, incipient A horizons were buried during waning valley-bottom aggradation. At two localities, the buried flood-plain is evident as a clay-rich stratum that must have been deposited in a paleochannel. Flood-plain stabilization between 5700 and 5100 cal. year BP probably occurred in response to the effects of external climate forcing on vegetation and hydrologic changes. Flood-plains of other rivers in the central Great Plains also stabilized at this time, further supporting a climatic explanation for slowing of valley aggradation and formation of a flood-plain at this time. Recognition of buried flood-plains is important to both soil mapping in valleys and to the discovery of cultural resources in valleys.

  11. Deconvolving Flood Plain Dynamical Processes from Pedogenic Processes on Ancient Floodplains

    NASA Astrophysics Data System (ADS)

    Sheldon, N. D.

    2014-12-01

    Paleosols (fossil soils) preserved in ancient floodplain systems represent one of the most widely used and potentially powerful continental paleoclimatic archives. At the same time, to apply most of the quantitative paleoclimate proxies requires the deconvolution of floodplain dynamics from pedogenic processes. For example, a paleosol could be weakly developed because of low atmospheric CO2 levels, low amounts of precipitation, or because of short formation duration due to frequent channel avulsion. The interpretation of local floodplain dynamics in paleo-floodplain systems is often simplistic, assuming both straightforward uniformitarianism and also that a single vertical section represents that lateral diversity of environments, however, these assumptions have rarely, if ever, been put to the test. Herein, a variety of paleoclimatic and paleobiological proxies will be examined in well-preserved paleo-floodplain settings in Spain, Wyoming, and Montana to test those assumptions. Multi-proxy (phytolith, stable isotope) paleovegetation studies along paleo-floodplain transects in Montana (Miocene, Eocene) indicate substantial heterogeneity at the scale of tens to hundreds of meters, floodplain dynamics-driven succession, and cryptic paludal or everwet areas that are not recognizable purely on the basis of sedimentology. Similarly, rapidly aggrading floodplains in fluvial distributary systems (Spain, Miocene) or in dryland basins (Montana) often record significant mismatches between paleosol-based and paleobotanically based estimates of paleoprecipitation, likely due to variable sediment accumulation rates. Both of those sets of results indicate that single vertical sections are unlikely to represent the breadth floodplain environments and properties operating across paleo-floodplain systems. In contrast, newly described mineralogical proxies based on rock magnetics that can be used to reconstruct paleoclimatic/paleoenvironmental properties appear to be robust at the

  12. Spatial variability in hydrologic connectivity between a coastal river and its floodplain

    NASA Astrophysics Data System (ADS)

    Castillo, C. R.; Guneralp, I.; Hales, B. U.

    2015-12-01

    Significant in the transport and dispersal of energy, matter, and biota within riverine environments, hydrologic connectivity has become fundamental in understanding river-floodplain process and concepts associated with environmental flows. Hydrologic connectivity between a river and its floodplain is dependent on floodplain geomorphology, channel hydraulics, land cover, and groundwater dynamics. In this study, we examine the floodplain morphology of the Mission River on the Coastal Bend of Texas. Utilizing a LiDAR-derived digital elevation model, we develop a relative digital elevation model (RDEM), with respect to river-stage, for a reach of the river-floodplain system. To assess the dominant flow directions, and thus, characterize the connectivity within the floodplain, we determine hydrological facets—landscape patches with their own respective outlet and high internal surface water connectivity. Guided by historical streamflow records, we systematically threshold the RDEM to determine the spatial characteristics of floodplain inundation under various river-stages. The increasing aerial extent of floodplain inundation from increases in river-stage results in distinct patterns of river channel-floodplain connectivity. We analyze the spatial arrangement of facets with regard to inundation in order to quantify floodplain connectivity and complexity at various river-stages using graph theory and landscape metrics. Our results indicate that floodplain connectivity and complexity change nonlinearly with increases in river-stage; with the greatest increases in connectivity and complexity occurring well below bankfull discharge. Floodplains provide valuable ecosystem services and this study helps improve our understanding of process-form relationships in river-floodplain systems' that informs environmental policy for effective management of these services.

  13. A multilevel structural equation modeling analysis of vulnerabilities and resilience resources influencing affective adaptation to chronic pain.

    PubMed

    Sturgeon, John A; Zautra, Alex J; Arewasikporn, Anne

    2014-02-01

    The processes of individual adaptation to chronic pain are complex and occur across multiple domains. We examined the social, cognitive, and affective context of daily pain adaptation in individuals with fibromyalgia and osteoarthritis. By using a sample of 260 women with fibromyalgia or osteoarthritis, we examined the contributions of pain catastrophizing, negative interpersonal events, and positive interpersonal events to daily negative and positive affect across 30days of daily diary data. Individual differences and daily fluctuations in predictor variables were estimated simultaneously by utilizing multilevel structural equation modeling techniques. The relationships between pain and negative and positive affect were mediated by stable and day-to-day levels of pain catastrophizing as well as day-to-day positive interpersonal events, but not negative interpersonal events. There were significant and independent contributions of pain catastrophizing and positive interpersonal events to adaptation to pain and pain-related affective dysregulation. These effects occur both between persons and within a person's everyday life.

  14. Deposition and storage of solid-bound heavy metals in the floodplains of the River Geul (the Netherlands).

    PubMed

    Leenaers, H

    1991-08-01

    Because of past mining activities, the floodplains of the River Geul are polluted with heavy metals. The continuous supply of fresh sediments during floods has caused the floodplain soils to exhibit large quality variations in time. By measurements of (137)Cs deposition rates in part of the floodplain area were determined at 0.4 to 2.7 cm yr(-1). Analysis of soil metal concentrations at various depths at 65 locations, revealed that the upper 40 cm of the soil profile deposited during the past 30-45 yr, exhibit the highest metal levels. The geostatistical interpolation technique kriging was used to map actual and past pollution patterns. It was shown that, as a result of variable deposition rates, the spatial correlation structure of soil metal concentrations becomes less clear with increasing depth/age. Kriged maps of average metal concentrations in the upper 100 cm of the soil profile provided the basis for the calculation of the mass storage of heavy metals.

  15. Fish assemblage dynamics in a Neotropical floodplain relative to aquatic macrophytes and the homogenizing effect of a flood pulse

    USGS Publications Warehouse

    Gomes, L.C.; Bulla, C. K.; Agostinho, A. A.; Vasconcelos, L. P.; Miranda, Leandro E.

    2012-01-01

    The presence of aquatic macrophytes is a key factor in the selection of habitats by fish in floodplain lakes because these plants enhance the physical and biological complexities of aquatic habitats. The seasonal flood pulse may influence this interaction, but there is no information in the literature about the effects that flood events may have on macrophytes assemblages and its associated effects on fish assemblages. Thus, this article aimed to investigate whether species richness, evenness and similarities in fish assemblage composition differed between littoral areas vegetated with macrophytes and unvegetated areas, before and after a flood. We sampled three lakes in the floodplain of the upper Paraná River basin. Sampling was conducted before (December 2004 and January 2005) and after (early March, late March and May 2005) a flood event. Overall, species richness and evenness were higher in macrophytes-covered areas. Before the flood, the composition of fish assemblages was distinct when comparing vegetated and unvegetated areas. After the flood, the similarity in fish assemblage composition was higher, indicating a homogenization effect of floods for fish inhabiting littoral areas of floodplain lakes. After the flood, opportunistic species dominated the fish assemblages in aquatic macrophytes, apparently restructuring assemblages in the littoral, restarting a succession process. Thus, the observed homogenization effect of the flood could minimize biological interactions and could induce fish assemblages to begin a new process of structurization.

  16. Carbon cycling in floodplain ecosystems: excess pCO2, extreme δ13C, and snail shell proxies

    NASA Astrophysics Data System (ADS)

    Gray, D. P.; Horton, T. W.

    2010-12-01

    Braided river floodplains typically possess high vertical hydrological/hydrogeological connectivity. This surface-subsurface exchange is highly important in the overall function and structure of these complex 4-dimensional systems, including the ecosystems they support. Spring-fed streams on the floodplain are often hotspots of benthic invertebrate diversity and productivity. Here, δ13C values of both dissolved inorganic carbon (DIC) and food-web components from five braided fluvial floodplain spring-fed streams in New Zealand, are used to assess the source of carbon in spring-fed food-webs. Partial pressures of CO2 in spring water ranged from 2-7 times atmospheric pressure, but rapidly approached equilibrium with the atmosphere downstream commensurate with an increase in DIC δ13C. Survey results demonstrate that both out-gassing and photosynthetic draw-down by aquatic plants controlled the net flux of CO2. The gradient in DIC δ13C was transmitted through three trophic levels of spring food-webs. These findings suggest highly productive spring-fed ecosystems are ‘fertilized’ by excess carbon dioxide dissolved in subsurface source waters. Furthermore, the stable carbon isotope composition of gastropod shells and soft tissue can serve as proxies for groundwater derived carbon in spring-fed braided fluvial ecosystems.

  17. Reproductive biology of freshwater fishes from the Venezuelan floodplains.

    PubMed

    Guerrero, H Y; Cardillo, E; Poleo, G; Marcano, D

    2009-03-01

    This review describes the endocrine changes that occur during the annual reproductive cycle of Pygocentrus cariba, Pimelodus blochii, and Oxydoras sifontesi and their relationships with the environmental characteristics of Venezuelan floodplains. Most reproductive studies of teleosts have focused on changes that occur during annual cycles in temperate species but, in tropical fish, this has been examined less frequently. P. cariba, P. blochii, and O. sifontesi are seasonal breeders widely distributed along the Orinoco River. Under natural conditions they have an annual gonadal cycle closely related to changes in the annual hydrology cycle of the Orinoco River which defines two seasons on the floodplain: inundation and isolation. The reproductive cycle of these species seems to be controlled by cues from the external environment. Relevant data about gonadal maturation, for example gonadosomatic index and sexual hormones secretion, are contrasted. The role of catecholamines in neuroendocrine control of the reproductive axis is also considered in this work.

  18. Energy crops on floodplains - flood risk or benefit?

    NASA Astrophysics Data System (ADS)

    Rosolova, Zdenka; Baylis, Adam; Rose, Steve

    2010-05-01

    Land use and land management on floodplains have increasingly come into focus, particularly in relation to their impact on flooding. To date, research and modelling has explored the impact of land use changes such as floodplain afforestation, changes to management of upland moorlands or re-establishment of wet meadows on floodplains. However, no such investigation has been carried out into the impact on floodplain flows of growing energy crops. In the UK, a strong emphasis is being given to promotion of renewable energy. Farmers are encouraged to plant energy crops such as Miscanthus or Short Rotation Crops (e.g. Willow) in suitable locations, which typically exclude farmland in Flood Zone 3 (i.e. areas likely to be flooded by an event with a 100-year return period). However, there is a lack of understanding as to what impact, if any, the dense character of these crops planted on floodplains might have on flooding. This gap in knowledge currently prevents energy crops from being planted in areas where they could provide high economic and environmental benefit, and even possibly contribute to flood mitigation. At present, no guidance or policy exists to advise whether allowing farmers to establish energy crop plantations in Flood Zone 3 could alter the existing flood risk. Consequently, if energy crops could provide a coupled benefit of renewable energy source and flood mitigation, this benefit is not being utilised. To help fill in this gap in knowledge, a short term project was carried out in order to investigate, using suitable hydraulic modelling, the possible scale of impact of growing energy crops on river and floodplain flows, flood depth and overall impact on flood risk locally as well as downstream. 2D hydraulic modelling using TUFLOW was deemed to be the most appropriate approach for these investigations. The methodology included gaining an understanding of the life cycle and planting regime of Miscanthus and Willow, review of current knowledge on the

  19. White matter structure in the uncinate fasciculus: Implications for socio-affective deficits in Autism Spectrum Disorder.

    PubMed

    Samson, Andrea C; Dougherty, Robert F; Lee, Ihno A; Phillips, Jennifer M; Gross, James J; Hardan, Antonio Y

    2016-09-30

    Individuals with Autism Spectrum Disorder (ASD) have social and communication deficits and difficulties regulating emotions. The brain bases of these socio-affective deficits are not yet clear, but one candidate is structural connectivity in the left uncinate fasciculus, which connects limbic temporal and frontal areas thought to be involved in socio-affective processing. In this study, we assessed white matter structure in the left and right uncinate fasciculus in 18 high-functioning individuals with ASD and 18 group-matched typically developing (TD) controls using Diffusion Tensor Imaging. To test specificity of the associations, we also examined the association between both uncinate fasciculi and restricted and repetitive behaviors. Compared to TD individuals, individuals with ASD had significantly lower fractional anisotropy (FA) in the left and right uncinate. Group status significantly moderated the association between left uncinate and socio-affective deficits, indicating that within the ASD group, FA was associated with socio-affective deficits: Individuals with ASD with lower FA in the left uncinate had significantly more social and emotion regulation deficits. There was no association with restricted and repetitive behaviors. This study provides evidence that the left uncinate may play a critical role in socio-affective skills in individuals with ASD. PMID:27552717

  20. Groundwater salinity in a floodplain forest impacted by saltwater intrusion

    NASA Astrophysics Data System (ADS)

    Kaplan, David A.; Muñoz-Carpena, Rafael

    2014-11-01

    Coastal wetlands occupy a delicate position at the intersection of fresh and saline waters. Changing climate and watershed hydrology can lead to saltwater intrusion into historically freshwater systems, causing plant mortality and loss of freshwater habitat. Understanding the hydrological functioning of tidally influenced floodplain forests is essential for advancing ecosystem protection and restoration goals, however finding direct relationships between hydrological inputs and floodplain hydrology is complicated by interactions between surface water, groundwater, and atmospheric fluxes in variably saturated soils with heterogeneous vegetation and topography. Thus, an alternative method for identifying common trends and causal factors is required. Dynamic factor analysis (DFA), a time series dimension reduction technique, models temporal variation in observed data as linear combinations of common trends, which represent unexplained common variability, and explanatory variables. DFA was applied to model shallow groundwater salinity in the forested floodplain wetlands of the Loxahatchee River (Florida, USA), where altered watershed hydrology has led to changing hydroperiod and salinity regimes and undesired vegetative changes. Long-term, high-resolution groundwater salinity datasets revealed dynamics over seasonal and yearly time periods as well as over tidal cycles and storm events. DFA identified shared trends among salinity time series and a full dynamic factor model simulated observed series well (overall coefficient of efficiency, Ceff = 0.85; 0.52 ≤ Ceff ≤ 0.99). A reduced multilinear model based solely on explanatory variables identified in the DFA had fair to good results (Ceff = 0.58; 0.38 ≤ Ceff ≤ 0.75) and may be used to assess the effects of restoration and management scenarios on shallow groundwater salinity in the Loxahatchee River floodplain.

  1. Groundwater salinity in a floodplain forest impacted by saltwater intrusion.

    PubMed

    Kaplan, David A; Muñoz-Carpena, Rafael

    2014-11-15

    Coastal wetlands occupy a delicate position at the intersection of fresh and saline waters. Changing climate and watershed hydrology can lead to saltwater intrusion into historically freshwater systems, causing plant mortality and loss of freshwater habitat. Understanding the hydrological functioning of tidally influenced floodplain forests is essential for advancing ecosystem protection and restoration goals, however finding direct relationships between hydrological inputs and floodplain hydrology is complicated by interactions between surface water, groundwater, and atmospheric fluxes in variably saturated soils with heterogeneous vegetation and topography. Thus, an alternative method for identifying common trends and causal factors is required. Dynamic factor analysis (DFA), a time series dimension reduction technique, models temporal variation in observed data as linear combinations of common trends, which represent unexplained common variability, and explanatory variables. DFA was applied to model shallow groundwater salinity in the forested floodplain wetlands of the Loxahatchee River (Florida, USA), where altered watershed hydrology has led to changing hydroperiod and salinity regimes and undesired vegetative changes. Long-term, high-resolution groundwater salinity datasets revealed dynamics over seasonal and yearly time periods as well as over tidal cycles and storm events. DFA identified shared trends among salinity time series and a full dynamic factor model simulated observed series well (overall coefficient of efficiency, Ceff=0.85; 0.52≤Ceff≤0.99). A reduced multilinear model based solely on explanatory variables identified in the DFA had fair to good results (Ceff=0.58; 0.38≤Ceff≤0.75) and may be used to assess the effects of restoration and management scenarios on shallow groundwater salinity in the Loxahatchee River floodplain.

  2. Calcareous palaeosols and temples in the floodplain of Thebes, Egypt: droughts and decisions

    NASA Astrophysics Data System (ADS)

    Graham, Angus; Hunter, Morag A.; Pennington, Benjamin T.; Strutt, Kristian D.

    2014-05-01

    The Egypt Exploration Society Theban Harbours and Waterscapes Survey (THaWS) works in the area around modern Luxor (Egypt), and investigates the extent to which the Egyptians manipulated the Nile and floodplain through canal and basin construction. A current focus of the project is to understand the relationship between the floodplain and a series of temples on the West Bank. A longstanding puzzle on the West Bank is why the temple of Amenhotep III (1390-1352 BCE) is not located in the same area as all the others. While 19 kings of the Egyptian New Kingdom (1550-1070 BCE) built their temples on the toe-slope of the limestone cliffs fronting onto the edge of the modern alluvium, Amenhotep's sits entirely on the modern floodplain. Egyptologists have suggested this was done to allow the inundation of the Nile to wash into the temple, symbolising and recreating the essential Egyptian cosmogony of the primeval mound. However, was it possible that a period of low Nile discharge enabled him to build on the alluvium whilst keeping the temple dry from the Nile floods? The project is testing this hypothesis through an interdisciplinary approach which provides focussed information on the development of the floodplain over historic time periods. It combines geophysical survey (Electrical Resistivity Tomography, Ground Penetrating Radar and magnetometry) with geoarchaeology using an Eijkelkamp hand auger and gouge auger with facies being dated using the stratigraphic sequence of ceramic fragments within them. Two fieldwork seasons have been carried out to date (Graham et al. 2012, 2013). Calcareous palaeosols c. 4m below the surface have been identified in three separate augers across a distance of 3 km on the West Bank floodplain, suggesting a period of low inundation levels / drought. At one of the locations an ancient surface appears to lie 0.3-0.4m above the calcisol. Ceramic fragments from this unit tentatively indicate a New Kingdom date. The strontium isotope record from

  3. Structural Weight of Aircraft as Affected by the System of Design

    NASA Technical Reports Server (NTRS)

    Hall, Charles Ward

    1924-01-01

    Various details of design or arrangement of the parts of airplane structures are shown and discussed, the use of these devices having resulted in the production of structures of adequate strength, yet of a weight less than one-half of the usual construction.

  4. Dance Class Structure Affects Youth Physical Activity and Sedentary Behavior: A Study of Seven Dance Types

    ERIC Educational Resources Information Center

    Lopez Castillo, Maria A.; Carlson, Jordan A.; Cain, Kelli L.; Bonilla, Edith A.; Chuang, Emmeline; Elder, John P.; Sallis, James F.

    2015-01-01

    Purpose: The study aims were to determine: (a) how class structure varies by dance type, (b) how moderate-to-vigorous physical activity (MVPA) and sedentary behavior vary by dance class segments, and (c) how class structure relates to total MVPA in dance classes. Method: Participants were 291 boys and girls ages 5 to 18 years old enrolled in 58…

  5. Does the Oganizational Structure Affect the Management of Universities in Uganda? An Empirical Analysis

    ERIC Educational Resources Information Center

    Zziwa, Gertrude

    2014-01-01

    The organisational structure of universities follows particular models that distinguish them from other learning institutions. This research investigated the effect of the organisational structure on the management of universities in Uganda using a sample of 361, 44% of whom were members of academic staff, and the rest contained university top…

  6. Does Gender-Specific Differential Item Functioning Affect the Structure in Vocational Interest Inventories?

    ERIC Educational Resources Information Center

    Beinicke, Andrea; Pässler, Katja; Hell, Benedikt

    2014-01-01

    The study investigates consequences of eliminating items showing gender-specific differential item functioning (DIF) on the psychometric structure of a standard RIASEC interest inventory. Holland's hexagonal model was tested for structural invariance using a confirmatory methodological approach (confirmatory factor analysis and randomization…

  7. Geochemical fractions of copper in soil chronosequences of selected European floodplains.

    PubMed

    Graf, M; Lair, G J; Zehetner, F; Gerzabek, M H

    2007-08-01

    The influence of soil formation on copper sorption is documented based on chronosequences of soils from three river floodplains in Europe (Danube, Ebro and Elbe). Sequential extraction was used to fractionate copper in original and spiked soils in order to study the long-term and short-term behaviour of copper retention. Copper partitioning among defined geochemical fractions was mainly determined by soil pH and the contents of carbonates, organic matter and Fe-/Mn-oxides and hydroxides. Copper extracted with NH(2)OH.HCl correlated well with the contents of crystalline Fe-oxides and hydroxides, demonstrating increasing retention capacity with progressing soil development. Copper retained in original soils was found in more strongly bound fractions, whereas sorption of freshly added copper was primarily influenced by the presence of carbonates. Beyond the effect of progressing soil formation, variations in organic carbon contents due to different land use history affected the copper retention capacity of the investigated soils.

  8. Habitat modeling in a southeastern aluvial floodplain river

    SciTech Connect

    Leonard, P.; Bell, C.; Boltz, J.

    1995-12-31

    The physical habitat modeling approach of the Instream Flow Incremental Methodology (IFIM) is frequently used to conduct impact assessments and determine instream flow needs downstream of hydroelectric facilities. In the process of relicensing the Sinclair Hydroelectric Project, Georgia Power Company conducted an IFIM study on a seventy-mile section of the Oconee River from Sinclair Dam downstream to Dublin, Georgia. The Oconee River in the study area is a low-gradient, meandering alluvial river with an extensive bottomland hardwood floodplain. Knowledge of such southeastern floodplain rivers suggests that in addition to the traditional IFIM concepts of instream habitat, inclusion of other important habitat components such as woody debris substrates, access to seasonally inundated floodplain habitat, and recruitment from oxbow lakes are potentially important determinants of fish species composition and productivity which should be considered in instream flow studies. This paper describes: (1) several new habitat modeling approaches that were used to address these important habitat components within the context of IFIM; and, (2) how they were used as the basis for evaluating changes in habitat resulting from various alternative operations of the Sinclair Project.

  9. Avian assemblages in the lower Missouri river floodplain

    USGS Publications Warehouse

    Thogmartin, W.E.; Gallagher, M.; Young, N.; Rohweder, J.J.; Durbian, F.; Knutson, M.G.

    2009-01-01

    Floodplain habitat provides important migration and breeding habitat for birds in the midwestern United States. However, few studies have examined how the avian assemblage changes with different stages of floodplain forest succession in the midwestern United States. In spring and summer from 2002 to 2004, we conducted 839 point counts in wet prairie/forbs fields, 547 point counts in early successional forests, and 434 point counts in mature forests to describe the migrating and breeding bird assemblage in the lower Missouri River floodplain. We recorded 131, 121, and 141 species in the three respective habitats, a number higher than most locations in the midwestern United States and comprising > 15% of all avian species in North America. Avian species diversity generally increased from west to east along the river, differed among land cover classes, but overlapped between seasons (migration and breeding) and years. Wet prairies were particularly important for conservation as there were 20 species of high conservation concern observed, including Dickcissels (Spiza americana). Important species for monitoring biotic integrity included the Northern Harrier (Circus cyaneus) and Bobolink (Dolichonyx oryzivorus) in wet prairie, Bell's Vireo (Vireo bellii) in early successional forest, and Northern Parula (Parula americana) and Prothonotary Warbler (Protonotaria citrea) in mature forest. ?? 2009, The Society of Wetland Scientists.

  10. Factors Affecting Perceived Learning, Satisfaction, and Quality in the Online MBA: A Structural Equation Modeling Approach

    ERIC Educational Resources Information Center

    Sebastianelli, Rose; Swift, Caroline; Tamimi, Nabil

    2015-01-01

    The authors examined how six factors related to content and interaction affect students' perceptions of learning, satisfaction, and quality in online master of business administration (MBA) courses. They developed three scale items to measure each factor. Using survey data from MBA students at a private university, the authors estimated structural…

  11. How Will Welfare Reform Affect Childbearing and Family Structure Decisions? Discussion Paper.

    ERIC Educational Resources Information Center

    Peters, H. Elizabeth; Plotnick, Robert D.; Jeong, Se-Ook

    This paper summarizes changes in key elements of welfare policy and in closely related policies on child support enforcement and sex education and family planning programs. Drawing on a conceptual framework that highlights how incentives created by public policy can affect demographic behaviors, the paper concludes that, as Congress intended,…

  12. The Affective Structure of Stereotype Content: Behavior and Emotion in Intergroup Context

    ERIC Educational Resources Information Center

    Rogers, Kimberly B.; Schroder, Tobias; Scholl, Wolfgang

    2013-01-01

    Affect control theory and the stereotype content model share explanatory goals and employ compatible measurement strategies but have developed in largely separate literatures. The present article examines the models' commensurability and discusses new insights that can be gained by comparing theories. We first demonstrate that the unique…

  13. Study of the structure of synthetic opals affected by temperature and pressure

    NASA Astrophysics Data System (ADS)

    Somenkov, V. A.; Agafonov, S. S.; Glazkov, V. P.; Kovalenko, E. S.; Shushunov, M. N.

    2015-01-01

    It is demonstrated that synthetic opals, like most natural ones, have a cristobalite rather than quartz basis, change their color from white to blue after losing their water-containing component, and form superlattices. Being affected by temperature and pressure, they undergo partial or complete crystallization to the corresponding polymorphic modifications.

  14. Water-triacylglycerol interactions affect oil body structure and seed viability

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We are investigating interactions between water and triacylglycerols (TAG) that appear to affect oil body stability and viability of seeds. Dried seeds are usually stored at freezer temperatures (-20oC) for long-term conservation of genetic resources. This globally accepted genebanking practice is...

  15. Combining safety and nature: a multi-stakeholder perspective on integrated floodplain management.

    PubMed

    Fliervoet, J M; Van den Born, R J G; Smits, A J M; Knippenberg, L

    2013-10-15

    In The Netherlands, river management strategies and land use of floodplains have changed drastically over the last two decades. Due to an integrated and participatory planning style, many agricultural fields in floodplains were transformed to nature. The idea of "self-regulating nature" in the floodplains and policies such as Room for the River and WaalWeelde created more multifunctional and natural floodplains. In this way, during the planning phase, win-win situations were created between flood protection and nature. It was only later that obstacles occurred with regard to the maintenance of floodplains, mainly because of different perspectives of the stakeholders on how to reconcile flood protection and nature. Therefore this study focuses on the opinions of persons involved with 'future' floodplain management strategies, which have been divided into five themes: ·visions of floodplain management; ·collaborators in floodplain management; ·visions of nature and self-regulating nature; ·realization of Natura 2000 goals in floodplains; ·feasibility of the Cyclic Floodplain Rejuvenation (CFR) strategy. We interviewed various persons involved in river and nature management along the Waal River. Based on our findings, it is concluded that an integrated planning approach has not been incorporated into the maintenance strategies and programs and, as a result, new, innovative management strategies such as CFR are proving to be incompatible with 'static' regulations such as Natura 2000's conservation goals and flood protection norms. However, by exploring the responders' visions of nature, we found that the majority of them preferred a dynamic vision of floodplains and, for this reason, they have advocated for more flexibility in current policies related to river and nature management. Additionally, the respondents emphasized the importance of multi-stakeholder collaboration to realize the goal of cost-efficient floodplain management.

  16. Modeling effects of hydrological changes on the carbon and nitrogen balance of oak in floodplains.

    PubMed

    Pietsch, Stephan A; Hasenauer, Hubert; Kucera, Jiŕi; Cermák, Jan

    2003-08-01

    We extended the applicability of the ecosystem model BIOME-BGC to floodplain ecosystems to study effects of hydrological changes on Quercus robur L. stands. The extended model assesses floodplain peculiarities, i.e., seasonal flooding and water infiltration from the groundwater table. Our interest was the tradeoff between (a). maintaining regional applicability with respect to available model input information, (b). incorporating the necessary mechanistic detail and (c). keeping the computational effort at an acceptable level. An evaluation based on observed transpiration, timber volume, soil carbon and soil nitrogen content showed that the extended model produced unbiased results. We also investigated the impact of hydrological changes on our oak stands as a result of the completion of an artificial canal network in 1971, which has stopped regular springtime flooding. A comparison of the 11 years before versus the 11 years after 1971 demonstrated that the hydrological changes affected mainly the annual variation across years in leaf area index (LAI) and soil carbon and nitrogen sequestration, leading to stagnation of carbon and nitrogen stocks, but to an increase in the variance across years. However, carbon sequestration to timber was unaffected and exhibited no significant change in cross-year variation. Finally, we investigated how drawdown of the water table, a general problem in the region, affects modeled ecosystem behavior. We found a further amplification of cross-year LAI fluctuations, but the variance in soil carbon and nitrogen stocks decreased. Volume increment was unaffected, suggesting a stabilization of the ecosystem two decades after implementation of water management measures.

  17. Assessment of solvent effects: do weak alignment media affect the structure of the solute?

    PubMed

    Shahkhatuni, Astghik A; Shahkhatuni, Aleksan G; Panosyan, Henry A; Sahakyan, Aleksandr B; Byeon, In-Ja L; Gronenborn, Angela M

    2007-07-01

    Alignment media used for measuring residual dipolar couplings, such as solutions of filamentous phages, phospholipid mixtures, polyacrylamide gels and various lyotropic liquid crystalline systems were investigated with respect to solvent effects on molecular structure. Structural parameters of the small rigid model compound 13C-acetonitrile were calculated from dipolar couplings and variations from expectation values were used for assessment of solvent effects. Only minor solvent effects were observed for most of the media employed and the measured structural data are in good agreement with microwave data and theoretical predictions. PMID:17534883

  18. [Ecology of nutrition and differentiation of the trophic niches of bats (Chiroptera: Vespertilionidae) in floodplain ecosystems of the Samara Bend].

    PubMed

    Smirnov, D G; Vekhnik, V P

    2014-01-01

    A complex analysis of the food range of 15 bat species inhabiting floodplain ecosystems of the Samara Bend has been performed. It is shown that, in bats, an important component of the structuring of their communities is the division of food resources. The guild structure and position of species in the trophic space are described. Seven food guilds consisting of nonspecialized and specialized species are distinguished. It is noted that most species are characterized by a wide overlapping of their trophic niches, which may be a consequence of their weak competition in an environment that is rich in food resources.

  19. Monitoring flooding and vegetation on seasonally inundated floodplains with multifrequency polarimetric synthetic aperture radar

    NASA Astrophysics Data System (ADS)

    Hess, Laura Lorraine

    The ability of synthetic aperture radar to detect flooding and vegetation structure was evaluated for three seasonally inundated floodplain sites supporting a broad variety of wetland and upland vegetation types: two reaches of the Solimoes floodplain in the central Amazon, and the Magela Creek floodplain in Northern Territory, Australia. For each site, C- and L-band polarimetric Shuttle Imaging Radar-C (SIR-C) data was obtained at both high- and low-water stages. Inundation status and vegetation structure were documented simultaneous with the SIR-C acquisitions using low-altitude videography and ground measurements. SIR-C images were classified into cover states defined by vegetation physiognomy and presence of standing water, using a decision-tree model with backscattering coefficients at HH, VV, and HV polarizations as input variables. Classification accuracy was assessed using user's accuracy, producer's accuracy, and kappa coefficient for a test population of pixels. At all sites, both C- and L-band were necessary to accurately classify cover types with two dates. HH polarization was most. useful for distinguishing flooded from non-flooded vegetation (C-HH for macrophyte versus pasture, L-HH for flooded versus non-flooded forest), and cross-polarized L-band data provided the best separation between woody and non-woody vegetation. Increases in L-HH backscattering due to flooding were on the order of 3--4 dB for closed-canopy varzea and igapo forest, and 4--7 dB, for open Melaleuca woodland. The broad range of physiognomies and stand structures found in both herbaceous and woody wetland communities, combined with the variation in the amount of emergent canopy caused by water level fluctuations and phenologic changes, resulted in a large range in backscattering characteristics of wetland communities both within and between sites. High accuracies cannot be achieved for these communities using single-date, single-band, single-polarization data, particularly in the

  20. Structure and function of subsurface microbial communities affecting radionuclide transport and bio-immobilization

    SciTech Connect

    Stucki, Joseph William

    2013-05-13

    The purpose of this study was to provide comparative information regarding the changes in clay structure that occur due to biotic or abiotic reduction, as probed by variable-temperature Mössbauer spectroscopy.

  1. Parasites affect food web structure primarily through increased diversity and complexity

    USGS Publications Warehouse

    Dunne, Jennifer A.; Lafferty, Kevin D.; Dobson, Andrew P.; Hechinger, Ryan F.; Kuris, Armand M.; Martinez, Neo D.; McLaughlin, John P.; Mouritsen, Kim N.; Poulin, Robert; Reise, Karsten; Stouffer, Daniel B.; Thieltges, David W.; Williams, Richard J.; Zander, Claus Dieter

    2013-01-01

    Comparative research on food web structure has revealed generalities in trophic organization, produced simple models, and allowed assessment of robustness to species loss. These studies have mostly focused on free-living species. Recent research has suggested that inclusion of parasites alters structure. We assess whether such changes in network structure result from unique roles and traits of parasites or from changes to diversity and complexity. We analyzed seven highly resolved food webs that include metazoan parasite data. Our analyses show that adding parasites usually increases link density and connectance (simple measures of complexity), particularly when including concomitant links (links from predators to parasites of their prey). However, we clarify prior claims that parasites ‘‘dominate’’ food web links. Although parasites can be involved in a majority of links, in most cases classic predation links outnumber classic parasitism links. Regarding network structure, observed changes in degree distributions, 14 commonly studied metrics, and link probabilities are consistent with scale-dependent changes in structure associated with changes in diversity and complexity. Parasite and free-living species thus have similar effects on these aspects of structure. However, two changes point to unique roles of parasites. First, adding parasites and concomitant links strongly alters the frequency of most motifs of interactions among three taxa, reflecting parasites’ roles as resources for predators of their hosts, driven by trophic intimacy with their hosts. Second, compared to free-living consumers, many parasites’ feeding niches appear broader and less contiguous, which may reflect complex life cycles and small body sizes. This study provides new insights about generic versus unique impacts of parasites on food web structure, extends the generality of food web theory, gives a more rigorous framework for assessing the impact of any species on trophic

  2. Acidification of floodplains due to river level decline during drought.

    PubMed

    Mosley, Luke M; Palmer, David; Leyden, Emily; Cook, Freeman; Zammit, Benjamin; Shand, Paul; Baker, Andrew; W Fitzpatrick, Rob

    2014-06-01

    A severe drought from 2007 to 2010 resulted in the lowest river levels (1.75 m decline from average) in over 90 years of records at the end of the Murray-Darling Basin in South Australia. Due to the low river level and inability to apply irrigation, the groundwater depth on the adjacent agricultural flood plain also declined substantially (1-1.5 m) and the alluvial clay subsoils dried and cracked. Sulfidic material (pH>4, predominantly in the form of pyrite, FeS2) in these subsoils oxidised to form sulfuric material (pH<4) over an estimated 3300 ha on 13 floodplains. Much of the acidity in the deeply cracked contaminated soil layers was in available form (in pore water and on cation exchange sites), with some layers having retained acidity (iron oxyhydroxysulfate mineral jarosite). Post drought, the rapid raising of surface and ground water levels mobilised acidity in acid sulfate soil profiles to the floodplain drainage channels and this was transported back to the river via pumping. The drainage water exhibited low pH (2-5) with high soluble metal (Al, Co, Mn, Fe, Mn, Ni, and Zn) concentrations, in exceedance of guidelines for ecosystem protection. Irrigation increased the short-term transport of acidity, however loads were generally greater in the non-irrigation (winter) season when rainfall is highest (0.0026 tonnes acidity/ha/day) than in the irrigation (spring-summer) season (0.0013 tonnes acidity/ha/day). Measured reductions in groundwater acidity and increases in pH have been observed over time but severe acidification persisted in floodplain sediments and waters for over two years post-drought. Results from 2-dimensional modelling of the river-floodplain hydrological processes were consistent with field measurements during the drying phase and illustrated how the declining river levels led to floodplain acidification. A modelled management scenario demonstrated how river level stabilisation and limited irrigation could have prevented, or greatly lessened

  3. Acidification of floodplains due to river level decline during drought.

    PubMed

    Mosley, Luke M; Palmer, David; Leyden, Emily; Cook, Freeman; Zammit, Benjamin; Shand, Paul; Baker, Andrew; W Fitzpatrick, Rob

    2014-06-01

    A severe drought from 2007 to 2010 resulted in the lowest river levels (1.75 m decline from average) in over 90 years of records at the end of the Murray-Darling Basin in South Australia. Due to the low river level and inability to apply irrigation, the groundwater depth on the adjacent agricultural flood plain also declined substantially (1-1.5 m) and the alluvial clay subsoils dried and cracked. Sulfidic material (pH>4, predominantly in the form of pyrite, FeS2) in these subsoils oxidised to form sulfuric material (pH<4) over an estimated 3300 ha on 13 floodplains. Much of the acidity in the deeply cracked contaminated soil layers was in available form (in pore water and on cation exchange sites), with some layers having retained acidity (iron oxyhydroxysulfate mineral jarosite). Post drought, the rapid raising of surface and ground water levels mobilised acidity in acid sulfate soil profiles to the floodplain drainage channels and this was transported back to the river via pumping. The drainage water exhibited low pH (2-5) with high soluble metal (Al, Co, Mn, Fe, Mn, Ni, and Zn) concentrations, in exceedance of guidelines for ecosystem protection. Irrigation increased the short-term transport of acidity, however loads were generally greater in the non-irrigation (winter) season when rainfall is highest (0.0026 tonnes acidity/ha/day) than in the irrigation (spring-summer) season (0.0013 tonnes acidity/ha/day). Measured reductions in groundwater acidity and increases in pH have been observed over time but severe acidification persisted in floodplain sediments and waters for over two years post-drought. Results from 2-dimensional modelling of the river-floodplain hydrological processes were consistent with field measurements during the drying phase and illustrated how the declining river levels led to floodplain acidification. A modelled management scenario demonstrated how river level stabilisation and limited irrigation could have prevented, or greatly lessened

  4. Acidification of floodplains due to river level decline during drought

    NASA Astrophysics Data System (ADS)

    Mosley, Luke M.; Palmer, David; Leyden, Emily; Cook, Freeman; Zammit, Benjamin; Shand, Paul; Baker, Andrew; W. Fitzpatrick, Rob

    2014-06-01

    A severe drought from 2007 to 2010 resulted in the lowest river levels (1.75 m decline from average) in over 90 years of records at the end of the Murray-Darling Basin in South Australia. Due to the low river level and inability to apply irrigation, the groundwater depth on the adjacent agricultural flood plain also declined substantially (1-1.5 m) and the alluvial clay subsoils dried and cracked. Sulfidic material (pH > 4, predominantly in the form of pyrite, FeS2) in these subsoils oxidised to form sulfuric material (pH < 4) over an estimated 3300 ha on 13 floodplains. Much of the acidity in the deeply cracked contaminated soil layers was in available form (in pore water and on cation exchange sites), with some layers having retained acidity (iron oxyhydroxysulfate mineral jarosite). Post drought, the rapid raising of surface and ground water levels mobilised acidity in acid sulfate soil profiles to the floodplain drainage channels and this was transported back to the river via pumping. The drainage water exhibited low pH (2-5) with high soluble metal (Al, Co, Mn, Fe, Mn, Ni, and Zn) concentrations, in exceedance of guidelines for ecosystem protection. Irrigation increased the short-term transport of acidity, however loads were generally greater in the non-irrigation (winter) season when rainfall is highest (0.0026 tonnes acidity/ha/day) than in the irrigation (spring-summer) season (0.0013 tonnes acidity/ha/day). Measured reductions in groundwater acidity and increases in pH have been observed over time but severe acidification persisted in floodplain sediments and waters for over two years post-drought. Results from 2-dimensional modelling of the river-floodplain hydrological processes were consistent with field measurements during the drying phase and illustrated how the declining river levels led to floodplain acidification. A modelled management scenario demonstrated how river level stabilisation and limited irrigation could have prevented, or greatly

  5. Plant Defense Inhibitors Affect the Structures of Midgut Cells in Drosophila melanogaster and Callosobruchus maculatus.

    PubMed

    Li-Byarlay, Hongmei; Pittendrigh, Barry R; Murdock, Larry L

    2016-01-01

    Plants produce proteins such as protease inhibitors and lectins as defenses against herbivorous insects and pathogens. However, no systematic studies have explored the structural responses in the midguts of insects when challenged with plant defensive proteins and lectins across different species. In this study, we fed two kinds of protease inhibitors and lectins to the fruit fly Drosophila melanogaster and alpha-amylase inhibitors and lectins to the cowpea bruchid Callosobruchus maculatus. We assessed the changes in midgut cell structures by comparing them with such structures in insects receiving normal diets or subjected to food deprivation. Using light and transmission electron microscopy in both species, we observed structural changes in the midgut peritrophic matrix as well as shortened microvilli on the surfaces of midgut epithelial cells in D. melanogaster. Dietary inhibitors and lectins caused similar lesions in the epithelial cells but not much change in the peritrophic matrix in both species. We also noted structural damages in the Drosophila midgut after six hours of starvation and changes were still present after 12 hours. Our study provided the first evidence of key structural changes of midguts using a comparative approach between a dipteran and a coleopteran. Our particular observation and discussion on plant-insect interaction and dietary stress are relevant for future mode of action studies of plant defensive protein in insect physiology. PMID:27594789

  6. Plant Defense Inhibitors Affect the Structures of Midgut Cells in Drosophila melanogaster and Callosobruchus maculatus

    PubMed Central

    Li-Byarlay, Hongmei; Pittendrigh, Barry R.; Murdock, Larry L.

    2016-01-01

    Plants produce proteins such as protease inhibitors and lectins as defenses against herbivorous insects and pathogens. However, no systematic studies have explored the structural responses in the midguts of insects when challenged with plant defensive proteins and lectins across different species. In this study, we fed two kinds of protease inhibitors and lectins to the fruit fly Drosophila melanogaster and alpha-amylase inhibitors and lectins to the cowpea bruchid Callosobruchus maculatus. We assessed the changes in midgut cell structures by comparing them with such structures in insects receiving normal diets or subjected to food deprivation. Using light and transmission electron microscopy in both species, we observed structural changes in the midgut peritrophic matrix as well as shortened microvilli on the surfaces of midgut epithelial cells in D. melanogaster. Dietary inhibitors and lectins caused similar lesions in the epithelial cells but not much change in the peritrophic matrix in both species. We also noted structural damages in the Drosophila midgut after six hours of starvation and changes were still present after 12 hours. Our study provided the first evidence of key structural changes of midguts using a comparative approach between a dipteran and a coleopteran. Our particular observation and discussion on plant–insect interaction and dietary stress are relevant for future mode of action studies of plant defensive protein in insect physiology. PMID:27594789

  7. Plant Defense Inhibitors Affect the Structures of Midgut Cells in Drosophila melanogaster and Callosobruchus maculatus

    PubMed Central

    Li-Byarlay, Hongmei; Pittendrigh, Barry R.; Murdock, Larry L.

    2016-01-01

    Plants produce proteins such as protease inhibitors and lectins as defenses against herbivorous insects and pathogens. However, no systematic studies have explored the structural responses in the midguts of insects when challenged with plant defensive proteins and lectins across different species. In this study, we fed two kinds of protease inhibitors and lectins to the fruit fly Drosophila melanogaster and alpha-amylase inhibitors and lectins to the cowpea bruchid Callosobruchus maculatus. We assessed the changes in midgut cell structures by comparing them with such structures in insects receiving normal diets or subjected to food deprivation. Using light and transmission electron microscopy in both species, we observed structural changes in the midgut peritrophic matrix as well as shortened microvilli on the surfaces of midgut epithelial cells in D. melanogaster. Dietary inhibitors and lectins caused similar lesions in the epithelial cells but not much change in the peritrophic matrix in both species. We also noted structural damages in the Drosophila midgut after six hours of starvation and changes were still present after 12 hours. Our study provided the first evidence of key structural changes of midguts using a comparative approach between a dipteran and a coleopteran. Our particular observation and discussion on plant–insect interaction and dietary stress are relevant for future mode of action studies of plant defensive protein in insect physiology.

  8. Floodplain morphology, sedimentology, and development processes of a partially alluvial channel

    NASA Astrophysics Data System (ADS)

    Thayer, James B.; Ashmore, Peter

    2016-09-01

    The floodplain morphology, sediment deposits, and development mechanisms of a partially alluvial, low-moderate energy channel flowing over a mixed gravel/cobble-till bed are investigated and compared to existing ideas of floodplain development. The findings partially support the idea of a floodplain developed through lateral accretion capped with vertically accreted sediments as predicted by the energy-based classification scheme of Nanson and Croke (1992), though oblique accretion and partial channel avulsion are also important. Channel migration consists of limited cross-valley migration and downstream meander translation. Because of low channel sinuosity, well-formed neck cutoffs are rare, and instead the channel cuts headward along the insides of confined or underdeveloped meander bends forming a localized anabranching pattern. The floodplain architecture can be divided into gravel bar and bed deposits (GB), lateral accretion deposits (LA), overbank deposits (FF), and abandoned channel deposits (FF(CH)), which are described with four alluvial facies. Owing to the limited supply of coarse and fine sediment, none of the architectural elements are particularly thick, with total floodplain thickness being < 3 m. Floodplain development for partially alluvial channels is compared within a new floodplain discrimination framework. Comparisons with common facies models of single-thread, coarse-grained channels show important differences that suggest that the floodplain deposits and formative processes described herein represent a subset of single-thread systems that may be common in partially alluvial channels, particularly in slightly sinuous, coarse-grained channels of low-moderate energy with partly confined floodplains.

  9. An identification of the East Fork Poplar Creek floodplain, Anderson and Roane Counties, Tennessee

    SciTech Connect

    1992-12-01

    The work in this report was conducted by the US Army Corps of Engineers, Nashville District, during the period November 1991 through July 1992. The purpose of this study is to identify the East Fork Poplar Creek (EFPC) floodplain. This information is required as part of the remedial action plans for removal or containment of contamination within the EFPC floodplain. EFPC and a portion of its floodplain have been contaminated as a result of operations and accidental releases at the Department of Energy`s Y-12 Plant. Mercury is the major contaminant found in EFPC and its floodplain.

  10. Influence of flow variability on floodplain formation and destruction, Little Missouri River, North Dakota

    USGS Publications Warehouse

    Miller, J.R.; Friedman, J.M.

    2009-01-01

    Resolving observations of channel change into separate planimetric measurements of floodplain formation and destruction reveals distinct relations between these processes and the flow regime. We analyzed a time sequence of eight bottomland images from 1939 to 2003 along the Little Missouri River, North Dakota, to relate geomorphic floodplain change to flow along this largely unregulated river. At the decadal scale, floodplain formation and destruction varied independently. Destruction was strongly positively correlated with the magnitude of infrequent high flows that recur every 5-10 yr, whereas floodplain formation was negatively correlated with the magnitude of frequent low flows exceeded 80% of the time. At the century scale, however, a climatically induced decrease in peak flows has reduced the destruction rate, limiting the area made available for floodplain formation. The rate of destruction was not uniform across the floodplain. Younger surfaces were consistently destroyed at a higher rate than older surfaces, suggesting that throughput of contaminants would have occurred more rapidly than predicted by models that assume uniform residence time of sediment across the floodplain. Maps of floodplain ages produced by analysis of sequential floodplain images are similar to maps of forest ages produced through dendrochronology, confirming the assumption of dendrogeomorphic studies that riparian tree establishment in this system is limited to recent channel locations. ?? 2009 Geological Society of America.

  11. Geomorphic floodplain with organic matter (biomass) estimates for Fanno Creek, Oregon

    USGS Publications Warehouse

    Sobieszczyk, Steven

    2011-01-01

    Fanno Creek is a tributary to the Tualatin River and flows though parts of the southwest Portland metropolitan area. The stream is heavily influenced by urban runoff and shows characteristic flashy streamflow and poor water quality commonly associated with urban streams. This data set represents the geomorphic floodplain as derived from light detection and ranging (LiDAR) data and aerial photographic imagery. The floodplain represents current conditions including both anthropogenic alterations and natural historic floodplain features. The floodplain dataset is divided into 13 reach segments and attributed with corresponding organic material load estimates for each reach.

  12. Conditions that maximize floodplain downed wood volumes: a comparison across three biomes

    NASA Astrophysics Data System (ADS)

    Lininger, K.; Wohl, E.; Rose, J. R.; Sutfin, N. A.

    2015-12-01

    Floodplain downed wood can provide important habitat for aquatic, riparian, and terrestrial organisms. This wood, which can function as both a storage area and source for large wood in river channels, can also be a significant organic carbon stock in river-floodplain ecosystems. We present data on downed wood volumes for different floodplain vegetation communities in the central Yukon River Basin in interior Alaska. We measured downed wood volume per unit floodplain area and wood decay characteristics within four distinct floodplain vegetation communities, and equate downed wood volumes per unit area to total organic carbon per unit area. Preliminary results suggest that downed wood volumes are greatest in disturbed white spruce forests, compared to undisturbed white spruce, deciduous forests, and black spruce woody wetlands. Disturbances contributing to large wood volumes include fire, wind, and ice jam floods. We also compare wood volumes in interior Alaska to downed wood volumes in other unmanaged floodplain vegetation communities, including a subtropical lowland alluvial river-floodplain and a semi-arid mountainous river-floodplain. These three datasets provide comparisons of unmanaged riparian forests across diverse climatic settings and highlight the climatic conditions and biomes that result in substantial downed wood and organic carbon storage in floodplain environments.

  13. Limnology in the Upper Paraná River floodplain: large-scale spatial and temporal patterns, and the influence of reservoirs.

    PubMed

    Roberto, M C; Santana, N N; Thomaz, S M

    2009-06-01

    Knowledge of abiotic limnological factors is important to monitor changes caused by humans, and to explain the structure and dynamics of populations and communities in a variety of inland water ecosystems. In this study, we used a long term data-set (eight years) collected in 10 habitats with different features (river channels, and connected and isolated lakes) to describe the spatial and temporal patterns of some of the principal limnological factors. In general, the degree of connectivity of the lakes, together with the rivers to which the lakes are connected, were important determinants of their limnological characteristics. These differences are expected, because rivers entering the floodplain come from different geological regions and are subject to different human impacts. At large spatial scales, these differences contribute to the increased habitat diversity of the floodplain and thus to its high biodiversity. With regard to temporal variation, Secchi-disk transparency increased, and total phosphorus decreased in the Paraná River main channel during the last 20 years. Although these changes are directly attributed to the several reservoir cascades located upstream, the closing of the Porto Primavera dam in 1998 enhanced this effect. The increase in water transparency explains biotic changes within the floodplain. The lower-phosphorus Paraná River water probably dilutes concentrations of this element in the floodplain waterbodies during major floods, with future consequences for their productivity.

  14. Clinical and structural impact of mutations affecting the residue Phe367 of FOXP3 in patients with IPEX syndrome.

    PubMed

    Colobran, Roger; Álvarez de la Campa, Elena; Soler-Palacín, Pere; Martín-Nalda, Andrea; Pujol-Borrell, Ricardo; de la Cruz, Xavier; Martínez-Gallo, Mónica

    2016-02-01

    Immune dysregulation, polyendocrinopathy, enteropathy, X-linked (IPEX) syndrome is a monogenic autoimmune disease characterized by early-onset life-threatening multisystemic autoimmunity. This rare hereditary disorder is caused by loss-of-function mutations in the gene encoding the forkhead box P3 (FOXP3) transcription factor, which plays a key role in the differentiation and function of CD4(+)CD25(+) natural regulatory T cells (Tregs), essential for the establishment and maintenance of natural tolerance. We identified a novel mutation in the FOXP3 gene affecting the Phe367 residue of the protein (F367V) in a family with three male siblings affected by IPEX. Two other mutations affecting the FOXP3 Phe367 residue (F367L and F367C) have been described previously. This unique situation of three mutations affecting the same residue in FOXP3 led us to study the molecular impact of these mutations on the structure of FOXP3 protein. Structure analysis showed that Phe367 is involved in a rich interaction network related to both monomer and dimer structure stabilization, and is crucial for FOXP3 regulatory activity. The relevance of this location is confirmed by the results of SIFT and PolyPhen-2 pathogenicity predictions for F367V mutation. In summary, as assessment of the pathogenicity of a novel mutation is crucial to achieve a proper molecular diagnosis, we analysed the impact of mutations affecting the Phe367 residue using a combined approach that provides a mechanistic view of their pathogenic effect. PMID:26748374

  15. Ecohydrological controls over water budgets in floodplain meadows

    NASA Astrophysics Data System (ADS)

    Morris, Paul J.; Verhoef, Anne; Macdonald, David M. J.; Gardner, Cate M.; Punalekar, Suvarna M.; Tatarenko, Irina; Gowing, David

    2013-04-01

    Floodplain meadows are important ecosystems, characterised by high plant species richness including rare species. Fine-scale partitioning along soil hydrological gradients allows many species to co-exist. Concerns exist that even modest changes to soil hydrological regime as a result of changes in management or climate may endanger floodplain meadows communities. As such, understanding the interaction between biological and physical controls over floodplain meadow water budgets is important to understanding their likely vulnerability or resilience. Floodplain meadow plant communities are highly heterogeneous, leading to patchy landscapes with distinct vegetation. However, it is unclear whether this patchiness in plant distribution is likely to translate into heterogeneous soil-vegetation-atmosphere transfer (SVAT) rates of water and heat, or whether floodplain meadows can reasonably be treated as internally homogeneous in physical terms despite this patchy vegetation. We used a SVAT model, the Soil-Water-Atmosphere-Plants (SWAP) model by J.C. van Dam and co-workers, to explore the controls over the partitioning of water budgets in floodplain meadows. We conducted our research at Yarnton Mead on the River Thames in Oxfordshire, one of the UK's best remaining examples of a floodplain meadow, and which is still managed and farmed in a low-intensity mixed-use manner. We used soil and plant data from our site to parameterise SWAP; we drove the model using in-situ half-hourly meteorological data. We analysed