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Sample records for playa lake stage

  1. Playa Lakes

    Data.gov (United States)

    Kansas Data Access and Support Center — This digital dataset provides information about the spatial distribution of soil units associated with playa lakes. Specific soil types have been designated by the...

  2. Ecology of playa lakes

    Science.gov (United States)

    Haukos, David A.; Smith, Loren M.

    1992-01-01

    Between 25,000 and 30,000 playa lakes are in the playa lakes region of the southern high plains (Fig. 1). Most playas are in west Texas (about 20,000), and fewer, in New Mexico, Oklahoma, Kansas, and Colorado. The playa lakes region is one of the most intensively cultivated areas of North America. Dominant crops range from cotton in southern areas to cereal grains in the north. Therefore, most of the native short-grass prairie is gone, replaced by crops and, recently, grasses of the Conservation Reserve Program. Playas are the predominant wetlands and major wildlife habitat of the region.More than 115 bird species, including 20 species of waterfowl, and 10 mammal species have been documented in playas. Waterfowl nest in the area, producing up to 250,000 ducklings in wetter years. Dominant breeding and nesting species are mallards and blue-winged teals. During the very protracted breeding season, birds hatch from April through August. Several million shorebirds and waterfowl migrate through the area each spring and fall. More than 400,000 sandhill cranes migrate through and winter in the region, concentrating primarily on the larger saline lakes in the southern portion of the playa lakes region.The primary importance of the playa lakes region to waterfowl is as a wintering area. Wintering waterfowl populations in the playa lakes region range from 1 to 3 million birds, depending on fall precipitation patterns that determine the number of flooded playas. The most common wintering ducks are mallards, northern pintails, green-winged teals, and American wigeons. About 500,000 Canada geese and 100,000 lesser snow geese winter in the playa lakes region, and numbers of geese have increased annually since the early 1980’s. This chapter describes the physiography and ecology of playa lakes and their attributes that benefit waterfowl.

  3. Estimating playa lake flooding: Edwards Air Force Base, California, USA

    Science.gov (United States)

    French, Richard H.; Miller, Julianne J.; Dettling, Charles R.

    2005-05-01

    Playa, or terminal lakes are essentially flat surfaces with minimal topographic relief, and they are common in most semi and arid-environments. Both ground and surface waters can accumulate within a terminal basin and result in flooding of the playa. Within the boundaries of Edwards Air Force Base, located in Southern California, there are four playas: Rosamond, Buckhorn, Rogers, and Rich Dry Lakes. The Rosamond and Rogers playas are currently and have historically been used as runways, taxiways, and industrial areas by the US Air Force and National Aeronautics and Space Administration. A flood assessment of Rogers Dry Lake was mandated due to Air Force regulations concerning delineation of 100-year flood hazard zones, and US Federal regulations, which specify that playas are 100-year special flood hazard zones. From an environmental viewpoint, when water is present, playa lakes can also provide habitat for migratory birds. There is neither guidance nor a generally accepted approach for identifying flood hazards on playas. Therefore, an approach was developed to determine the 100-year regulatory floodplain associated with a dry lakebed, and this approach was used to define tile regulatory floodplain on Rogers and Rich Dry Lakes. This paper describes the application of the method developed to estimate the regulatory 100-year depth of water on Roger and Rich Dry Lakes.

  4. Anthropogenic climate change in the Playa Lakes Joint Venture region

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Anthropogenic climate change has been driving regional climate shifts in the Playa Lakes Joint Venture zone since at least the mid 1970s. As a result, summers are...

  5. Water regime of Playa Lakes from southern Spain: conditioning factors and hydrological modeling.

    Science.gov (United States)

    Moral, Francisco; Rodriguez-Rodriguez, Miguel; Beltrán, Manuel; Benavente, José; Cifuentes, Victor Juan

    2013-07-01

    Andalusia's lowland countryside has a network of small geographically isolated playa lakes scattered across an area of 9000 km2 whose watersheds are mostly occupied by clayey rocks. The hydrological model proposed by the authors seeks to find equilibrium among usefulness, simplicity, and applicability to isolated playas in a semiarid context elsewhere. Based in such model, the authors have used monthly climatic data, water stage measurements, and the basin morphometry of a particular case (Los Jarales playa lake) to calibrate the soil water budget in the catchment and the water inputs from the watershed (runoff plus groundwater flow) at different scales, from monthly to daily. After the hydrologic model was calibrated, the authors implemented simulations with the goal of reproducing the past hydrological dynamics and forecasting water regime changes that would be caused by a modification of the wetland morphometry.

  6. Investigation of a playa lake bed using geophysical electrical methods

    Science.gov (United States)

    Herrmenn, M.; Gurrola, H.; William, R.; Montalvo, R.; Horton, S.; Homberg, J.; Allen, T.; Bribiesca, E.; Lindsey, C.; Anderson, H.; Seshadri, S.; Manns, S.; Hassan, A.; Loren, C.

    2005-12-01

    The 2005 undergraduate applied geophysical class of Texas Tech University conducted a geophysical survey of a playa lake approximately 10 miles northwest of Lubbock Texas. The playa lake is primarily used as grazing land for two llamas and a hand full of sheep, and has been recently used as a dump for broken down sheds and barrels. Our goal was to model the subsurface of the transition from the playa to plains geology and investigate the possible contamination, of the soil and the data, by the metal dumped at the surface. We conducted our survey with and EM31 and homemade D.C. resistivity and SP equipment that allowed students to grasp the theories more clearly. SP readings were collected using clay pots constructed from terracotta pots and copper tubing purchased at the local hardware store and voltage measurements collected with handle held multi-meters. D.C. resistivity data were collected in a dipole-dipole array using 20 nine volt batteries connected in series with a large enough variable resistor and amp meter to regulate steady current flow. A multi meter was used to collect voltage readings. Wenner array data were collected using a home-made multi-filament cable connected switch box to allow a central user to regulate current and take voltage reading. A map of conductivity produced from a 10 m of EM31 reading show that conductivity anomalies mirror topography. The SP profiles show high values in the playa lake that drop off as we move from the clay rich lake bed to normal grassland. Analysis of both the Dipole-Dipole and Wenner array data support a model with 3 flat layers increasing in resistivity with depth. It appears that these remain flat passing beneath the playa and the playa is eroded into these layers.

  7. Bacterial succession within an ephemeral hypereutrophic mojave desert playa lake

    Science.gov (United States)

    Navarro, J.B.; Moser, D.P.; Flores, A.; Ross, C.; Rosen, Michael R.; Dong, H.; Zhang, G.; Hedlund, B.P.

    2009-01-01

    Ephemerally wet playas are conspicuous features of arid landscapes worldwide; however, they have not been well studied as habitats for microorganisms. We tracked the geochemistry and microbial community in Silver Lake playa, California, over one flooding/desiccation cycle following the unusually wet winter of 2004-2005. Over the course of the study, total dissolved solids increased by 10-fold and pH increased by nearly one unit. As the lake contracted and temperatures increased over the summer, a moderately dense planktonic population of 1 ?????106 cells ml-1 of culturable heterotrophs was replaced by a dense population of more than 1????????109 cells ml-1, which appears to be the highest concentration of culturable planktonic heterotrophs reported in any natural aquatic ecosystem. This correlated with a dramatic depletion of nitrate as well as changes in the microbial community, as assessed by small subunit ribosomal RNA gene sequencing of bacterial isolates and uncultivated clones. Isolates from the early-phase flooded playa were primarily Actinobacteria, Firmicutes, and Bacteroidetes, yet clone libraries were dominated by Betaproteobacteria and yet uncultivated Actinobacteria. Isolates from the late-flooded phase ecosystem were predominantly Proteobacteria, particularly alkalitolerant isolates of Rhodobaca, Porphyrobacter, Hydrogenophaga, Alishwenella, and relatives of Thauera; however, clone libraries were composed almost entirely of Synechococcus (Cyanobacteria). A sample taken after the playa surface was completely desiccated contained diverse culturable Actinobacteria typically isolated from soils. In total, 205 isolates and 166 clones represented 82 and 44 species-level groups, respectively, including a wide diversity of Proteobacteria, Bacteroidetes, Actinobacteria, Firmicutes, Gemmatimonadetes, Acidobacteria, and Cyanobacteria. ?? 2008 Springer Science+Business Media, LLC.

  8. Estimating Recharge through Playa Lakes to the Southern High Plains Aquifer

    Science.gov (United States)

    Rainwater, K.; Ganesan, G.; Gitz, D.; Zartman, R.; Hudnall, W.; Smith, L.

    2009-12-01

    In the Southern High Plains of Texas, it is accepted that focused recharge to the High Plains Aquifer (locally known as the Ogallala) occurs through over 20,000 playa lakes, which are local depressions that collect storm runoff. The amount and rate of recharge is not precisely known, and the impact of the land use surrounding each playa lake on the amount of runoff has not been quantified. Each playa exists within its own watershed, and many of those are cultivated, while others are surrounded by native grassland or conservation reserve program (CRP) lands. The amount of sediments entering most playas following cultivation has been substantial, but whether this erosion has had a harmful influence on recharge is unknown. Changing recharge rates can also impact the playa ecosystems that are pivotal to many types of local wildlife. Improved understanding of playa recharge is necessary for proper management strategies for long-term survivability of the Ogallala aquifer. Over the last four years, the research team selected and instrumented 30 playas (10 counties, one cropland playa, one native grassland playa, one CRP playa in each) for observation of their water budgets. To quantify recharge in each playa, data collection includes sufficient weather instrumentation to determine local precipitation and free water evaporation, as well as water level monitoring in the playa lake. The depth/area/volume relationship for each playa was developed by local GPS surveying. Between rainfall/runoff events, seepage through the playa bottom is calculated as the difference between the change in the volume of water stored in the playa and the calculated free water evaporation. The research team hopes to keep the instrumentation operational for as long as possible, hopefully several years, to observe enough inundation events to characterize a range of behaviors in the different playa basins. In this presentation, initial water budget analyses for several of the initially instrumented

  9. Dust Generation Resulting from Desiccation of Playa Systems: Studies on Mono and Owens Lakes, California

    Science.gov (United States)

    Gill, Thomas Edward

    1995-01-01

    Playas, evaporites, and aeolian sediments frequently are linked components within the Earth system. Anthropogenic water diversions from terminal lakes form playas that release fugitive dust. These actions, documented worldwide, simulate aeolian processes activated during palaeoclimatic pluvial/interpluvial transitions, and have significant environmental impacts. Pluvial lakes Russell and Owens in North America's Great Basin preceded historic Mono and Owens Lakes, now desiccated by water diversions into dust-generating, evaporite -encrusted playas. Geochemical and hydrologic cycles acting on the Owens (Dry) Lake playa form three distinct crust types each year. Although initial dust production results from deflation of surface efflorescences after the playa dries, most aerosols are created by saltation abrasion of salt/silt/clay crusts at crust/ sand sheet contacts. The warm-season, clastic "cemented" crust is slowest to degrade into dust. If the playa surface is stabilized by an unbroken, non-efflorescent crust, dust formation is discouraged. When Mono Lake's surFace elevation does not exceed 1951 meters (6400 feet), similar processes will also generate dust from its saline lower playa. Six factors--related to wind, topography, groundwater, and sediments--control dust formation at both playas. These factors were combined into a statistical model relating suspended dust concentrations to playa/lake morphometry. The model shows the extent and severity of Mono Lake dust storms expands significantly below the surface level 6376 feet (1943.5 meters). X-ray diffraction analysis of Mono Basin soils, playa sediments, and aerosols demonstrates geochemical cycling of materials through land, air and water during Mono Lake's 1982 low stand. Soils and clastic playa sediments contain silicate minerals and tephra. Saline groundwater deposited calcite, halite, thenardite, gaylussite, burkeite and glauberite onto the lower playa. Aerosols contained silicate minerals (especially

  10. A hydrological simulation of the water regime in two playa lakes located in southern Spain

    Indian Academy of Sciences (India)

    Rodriguez-Rodriguez Miguel; Schilling Malte

    2014-08-01

    The subject of this paper is the detailed hydrological simulation of two playa lakes located in southern Spain from January 2011 to March 2012 on a daily basis. These playas are placed over a 400-km2 shallow aquifer, which is exposed to an increasing stress caused by agricultural activities, mainly olive grove plantations. The objective of the paper is to elaborate a detailed numeric model that simulates the water regime of each playa lake on a daily scale. The simulation is compared to measured water level (WL) data of the playas in order to characterize the groundwater–surface interactions. The ultimate objective of this paper is to assess the environmental impact of the increasing anthropogenic water consumption within the area of research. The results of the GW–surface interaction were very consistent with previous works. One of the playa lakes is groundwater-dependent and the other one is presumably a perched playa lake. The GW discharge of the former playa (214 mm) during the research period stands in sharp contrast to no regional GW discharge in the latter. Water level data prove that the hydrological year (2011–2012) had a very negative water budget. The evapotranspiration estimation was almost as high as double the sum of the precipitation, the runoff, and the groundwater discharge. The simulation of an anthropologically altered water regime proves that water retrieval has a harmful impact on the WL of the playa lakes as well as on the aquifer.

  11. Environmental contaminants in water, sediment and biological samples from Playa Lakes in southeastern New Mexico - 1992

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Sediment, water, bird tissue, and invertebrates were collected from 10 playa lakes in Southeastern New Mexico in 1991 and 1992. These samples were analyzed for a...

  12. Playa Lakes of the Texas High Plains: A contaminants survey & assessment of biological integrity

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — In response to increased interest in the quality of playa lakes and their recognition as valuable wildlife habitat, the Arlington Field Office of the U.S. Fish and...

  13. Hydrogeologic processes in saline systems: Playas, sabkhas, and saline lakes

    Science.gov (United States)

    Yechieli, Y.; Wood, W.W.

    2002-01-01

    Pans, playas, sabkhas, salinas, saline lakes, and salt flats are hydrologically similar, varying only in their boundary conditions. Thus, in evaluating geochemical processes in these systems, a generic water and solute mass-balance approach can be utilized. A conceptual model of a coastal sabkha near the Arabian Gulf is used as an example to illustrate the various water and solute fluxes. Analysis of this model suggests that upward flux of ground water from underlying formations could be a major source of solutes in the sabkha, but contribute only a small volume of the water. Local rainfall is the main source of water in the modeled sabkha system with a surprisingly large recharge-to-rainfall ratio of more than 50%. The contribution of seawater to the solute budget depends on the ratio of the width of the supratidal zone to the total width and is generally confined to a narrow zone near the shoreline of a typical coastal sabkha. Because of a short residence time of water, steady-state flow is expected within a short time (50,000 years). The solute composition of the brine in a closed saline system depends largely on the original composition of the input water. The high total ion content in the brine limits the efficiency of water-rock interaction and absorption. Because most natural systems are hydrologically open, the chemistry of the brines and the associated evaporite deposits may be significantly different than that predicted for hydrologically closed systems. Seasonal changes in temperature of the unsaturated zone cause precipitation of minerals in saline systems undergoing evaporation. Thus, during the hot dry season months, minerals exhibit retrograde solubility so that gypsum, anhydrite and calcite precipitate. Evaporation near the surface is also a major process that causes mineral precipitation in the upper portion of the unsaturated zone (e.g. halite and carnallite), provided that the relative humidity of the atmosphere is less than the activity of water

  14. Dust emission at Franklin Lake Playa, Mojave Desert (USA): Response to meteorological and hydrologic changes 2005-2008

    Science.gov (United States)

    Reynolds, Richard L.; Bogle, Rian C.; Vogel, John; Goldstein, Harland; Yount, James

    2009-01-01

    Playa type, size, and setting; playa hydrology; and surface-sediment characteristics are important controls on the type and amount of atmospheric dust emitted from playas. Soft, evaporite-rich sediment develops on the surfaces of some Mojave Desert (USA) playas (wet playas), where the water table is shallow (development of soft surfaces with thin, newly formed crusts that are vulnerable to wind erosion and (or) the production of loose aggregates of evaporite minerals that are quickly removed by even moderate winds. Dust loading may also increase when relatively high regional precipitation leads to decreasing depth to the water table, thereby increasing rates of vapor discharge, development of evaporite minerals, and temporary softening of playa surfaces. The seasonality of wind strength was not a major factor in dust-storm frequency at the playa. The lack of major dust emissions related to flood-derived sediment at Franklin Lake playa contrasts with some dry-lake systems elsewhere that may produce large amounts of dust from flood sediments. Flood sediments do not commonly accumulate on the surface of Franklin Lake playa because through-going drainage prevents frequent inundation and deposition of widespread flood sediment.

  15. Using Australian Acidic Playa Lakes as Analogs for Phyllosilicate and Sulfate Depositional Environments on Mars

    Science.gov (United States)

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

    2008-12-01

    Recent work on the origin of martian sulfates and their relationship to phyllosilicate deposits suggest that these deposits formed in different eras of Mars' history, under distinct environmental conditions. In southwestern Meridiani Planum phyllosilicates exist in close proximity to sulfate deposits. One possible explanation for this relationship is that it is an unconformable stratigraphic sequence, representing a significant change in aqueous geochemical conditions over time. Specifically, it may be interpreted to record a change in environment from neutral pH aqueous alteration in the Noachian to an acidic evaporitic system in the late Noachian to the Hesperian. On Earth, two different geochemical systems need not be evoked to explain such chemical variation. Acidic playa lakes in Western Australia have large pH differences separated by only a few tens of meters and demonstrate how highly variable chemistries can coexist over short distances in natural environments. Playa lakes on Earth tend to be dominated by lateral flow of water and salts leading to lateral chemical variation. Heterogeneity of playa mineralogy in Australia is due to the varied source rocks of brines and the mixing of dilute oxidizing brines and freshwater with the saturated evaporitic brines. This is evidenced by the ferricretes in the near-shore environment and more soluble phases in basin interiors. Playa lakes on Mars would be much larger than their terrestrial counterparts, leading to the prevalence of large-scale surface and crustal advection of water and salt rather than short-distance lateral flow, except at lake boundaries. Little or no influx of freshwater would preclude the formation of playa rim (e.g., crater rim) ferricretes and silcretes. Instead, we expect to see mainly vertical facies changes, and any diachronous lateral facies changes are expected to occur on very large spatial scales. Comparison of high spatial resolution, hyperspectral airborne data for Australian playa

  16. Surface water hydrology and geomorphic characterization of a playa lake system: Implications for monitoring the effects of climate change

    Science.gov (United States)

    Adams, Kenneth D.; Sada, Donald W.

    2014-03-01

    Playa lakes are sensitive recorders of subtle climatic perturbations because these ephemeral water bodies respond to the flux of diffuse and channelized flow from their watersheds as well as from direct precipitation. The Black Rock Playa in northwestern Nevada is one of the largest playas in North America and is noted for its extreme flatness, varying less than one meter across a surface area of 310 km2. Geo-referenced Landsat imagery was used to map surface-area fluctuations of ephemeral lakes on the playa from 1972 to 2013 to provide baseline data on surface water hydrology of this system to compare to future hydrologic conditions caused by climate change. The area measurements were transformed into depth and volumetric estimates using results of detailed topographic global positioning system (GPS) surveys and correlated with available surface hydrological and meteorological monitoring data. Playa lakes reach their maximum size (<350 km2) in spring, fed by melting snows from high mountains on the periphery of the drainage basin, and usually desiccate by early- to mid-summer. The combination of a shallow groundwater table, sediment deposition, and hydro-aeolian planation probably are largely responsible for the flatness of the playa. When lakes do not form for a period of several years, the clay- and silt-rich playa surface transforms from one that is hard and durable into one that is soft and puffy, probably from upward capillary movement of water and resultant evaporation. Subsequent flooding restores the hard and durable surface. The near-global availability of Landsat imagery for the last 41 years should allow the documentation of baseline surface hydrologic characteristics for a large number of widely-distributed playa lake systems that can be used to assess the hydrologic effects of future climate changes.

  17. Scattering behavior of Lunar Lake playa determined from parabola bidirectional reflectance data

    Science.gov (United States)

    Shepard, Michael K.; Arvidson, Raymond E.; Guinness, Edward A.; Deering, Donald W.

    1991-01-01

    Bidirectional reflectance data obtained with the Portable Apparatus for Rapid Acquisition of Bidirectional Observations of Land and Atmosphere instrument at Lunar Lake, Nevada, were analyzed to determine the scattering properties of playas. The data are approximated by a Lambertian function, except at high phase angles in the solar principal plane, where Fresnel reflectance appears to dominate. The data also depart slightly (15 percent) from a Lambertian function at high emission angles in all azimuthal planes. No published photometric model accounts for the observed data. It is hypothesized that the observed scattering behavior is the superposition of volume and surface (Fresnel) scattering mechanisms.

  18. Aeolian responses to climate variability during the past century on Mesquite Lake Playa, Mojave Desert

    Science.gov (United States)

    Whitney, J. W.; Breit, G. N.; Buckingham, S. E.; Reynolds, R. L.; Bogle, R. C.; Luo, L.; Goldstein, H. L.; Vogel, J. M.

    2015-02-01

    The erosion and deposition of sediments by wind from 1901 to 2013 have created large changes in surface features of Mesquite Lake playa in the Mojave Desert. The decadal scale recurrence of sand-sheet development, migration, and merging with older dunes appears related to decadal climatic changes of drought and wetness as recorded in the precipitation history of the Mojave Desert, complemented by modeled soil-moisture index values. Historical aerial photographs, repeat land photographs, and satellite images document the presence and northward migration of a mid-20th century sand sheet that formed during a severe regional drought that coincided with a multi-decadal cool phase of the Pacific Decadal Oscillation (PDO). The sand sheet slowly eroded during the wetter conditions of the subsequent PDO warm phase (1977-1998) due to a lack of added sediment. Sand cohesion gradually increased in the sand sheet by seasonal additions of salt and clay and by re-precipitation of gypsum, which resulted in the wind-carving of yardangs in the receding sand sheet. Smaller yardangs were aerodynamically shaped from coppice dunes with salt-clay crusts, and larger yardangs were carved along the walls and floor of trough blowouts. Evidence of a 19th century cycle of sand-sheet formation and erosion is indicated by remnants of yardangs, photographed in 1901 and 1916, that were found buried in the mid-20th century sand sheet. Three years of erosion measurements on the playa, yardangs, and sand sheets document relatively rapid wind erosion. The playa has lowered 20 to 40 cm since the mid-20th century and a shallow deflation basin has developed since 1999. Annually, 5-10 cm of surface sediment was removed from yardang flanks by a combination of wind abrasion, deflation, and mass movement. The most effective erosional processes are wind stripping of thin crusts that form on the yardang surfaces after rain events and the slumping of sediment blocks from yardang flanks. These wind

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

    Science.gov (United States)

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

    2009-06-01

    Recent Mars missions have stimulated considerable thinking about the surficial geochemical evolution of Mars. Among the major relevant findings are the presence in Meridiani Planum sediments of the mineral jarosite (a ferric sulfate salt) and related minerals that require formation from an acid-salt brine and oxidizing environment. Similar mineralogies have been observed in acidic saline lake sediments in Western Australia (WA), and these lakes have been proposed as analogues for acidic sedimentary environments on Mars. The prior version of the equilibrium chemical thermodynamic FREZCHEM model lacked Al and Si chemistries that are needed to appropriately model acidic aqueous geochemistries on Earth and Mars. The objectives of this work were to (1) add Al and Si chemistries to the FREZCHEM model, (2) extend these chemistries to low temperatures (lateral salt patterns in WA lakes. The WA playa lakes display significant lateral variations in mineralogy and water chemistry over short distances, reflecting the interaction of acid ground waters with neutral to alkaline lake waters derived from ponded surface runoff. Meridiani Planum observations indicate that such lateral variations are much less pronounced, pointing to the dominant influence of ground water chemistry, vertical ground water movements, and aeolian processes on the Martian surface mineralogy.

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

    Science.gov (United States)

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

    2009-01-01

    Recent Mars missions have stimulated considerable thinking about the surficial geochemical evolution of Mars. Among the major relevant findings are the presence in Meridiani Planum sediments of the mineral jarosite (a ferric sulfate salt) and related minerals that require formation from an acid-salt brine and oxidizing environment. Similar mineralogies have been observed in acidic saline lake sediments in Western Australia (WA), and these lakes have been proposed as analogues for acidic sedimentary environments on Mars. The prior version of the equilibrium chemical thermodynamic FREZCHEM model lacked Al and Si chemistries that are needed to appropriately model acidic aqueous geochemistries on Earth and Mars. The objectives of this work were to (1) add Al and Si chemistries to the FREZCHEM model, (2) extend these chemistries to low temperatures (patterns in WA lakes. The WA playa lakes display significant lateral variations in mineralogy and water chemistry over short distances, reflecting the interaction of acid ground waters with neutral to alkaline lake waters derived from ponded surface runoff. Meridiani Planum observations indicate that such lateral variations are much less pronounced, pointing to the dominant influence of ground water chemistry, vertical ground water movements, and aeolian processes on the Martian surface mineralogy. ?? 2009 Elsevier Ltd.

  1. Hydrogeological behaviour of the Fuente-de-Piedra playa lake and tectonic origin of its basin (Malaga, southern Spain)

    Science.gov (United States)

    Rodriguez-Rodriguez, Miguel; Martos-Rosillo, Sergio; Pedrera, Antonio

    2016-12-01

    Changes in the quantity of groundwater input due to water extraction for irrigation and urban supply has modified the water balance in the Fuente de Piedra playa lake. We have analysed the hydrogeology of the playa-lake system and developed a water-level model by means of a simple long-term water balance and piezometric analysis. In addition, a tectonic model is proposed to explain the endorheic basin development that led to the formation of the playa. Upright folds developed since the late Miocene and density-driven subsidence favoured the setting-up of and endorheic system located between the Atlantic and the Mediterranean basins in the Quaternary. The underlying low permeability rocks beneath the playa form a very stable aquitard with highly saline groundwater that prevents groundwater recharge of the lake into the aquitard. The hydrological modelling allowed us to simulate the evolution of the wáter level under a scenario of unaltered conditions during a 13-year period, showing that the percentage of days with dry conditions varies from 24.8% of the time under altered conditions to 14.9% as far as an unaltered scenario is concerned.

  2. Sodium toxicity and pathology associated with exposure of waterfowl to hypersaline playa lakes of southeast New Mexico

    Science.gov (United States)

    Meteyer, C.U.; Dubielzig, R.D.; Dein, F.J.; Baeten, L.A.; Moore, M.K.; Jehl, J.R.; Wesenberg, K.E.

    1997-01-01

    Cause of mortality was studied in waterfowl in hypersaline playa lakes of southeast New Mexico during spring and fall migration. Mortality was not common in wild ducks resting on the playas during good weather. However, when birds remained on the lakes for prolonged periods of time, such as during experimental trials and stormy weather, a heavy layer of salt precipitated on their feathers. Sodium toxicity was the cause of death for all experimental mallards housed on playa water and for 50% of the wild waterfowl found moribund or dead during the spring of 1995. Gross lesions included heavy salt precipitation on the feathers, ocular lens opacities, deeply congested brains, and dilated, thin-walled, fluid-filled cloacae. Microscopic lesions in the more severely affected birds included liquefaction of ocular lens cortex with lens fiber swelling and multifocal to diffuse ulcerative conjunctivitis with severe granulocytic inflammation, edema, and granulocytic vasculitis resulting in thrombosis. Inflammation similar to that seen in the conjunctiva occasionally involved the mucosa of the mouth, pharynx, nasal turbinates, cloaca, and bursa. Transcorneal movement of water in response to the hypersaline conditions on the playa lakes or direct contact with salt crystals could induce anterior segment dehydration of the aqueous humor and increased osmotic pressure on the lens, leading to cataract formation.

  3. Potential transport pathways of dust emanating from the playa of Ebinur Lake, Xinjiang, in arid northwest China

    Science.gov (United States)

    Ge, Yongxiao; Abuduwaili, Jilili; Ma, Long; Wu, Na; Liu, Dongwei

    2016-09-01

    In this paper, the HYSPLIT model, driven with reanalysis meteorological data from 1978 to 2013, was used to understand the potential transport characteristics of dust and salt dust emanating from the playa of Ebinur Lake in arid northwest China. Daily air parcel trajectories were computed forward for 8 days from an origin centered over Ebinur Lake at 100 m above ground level. Air parcel trajectory density plots were mapped for seven levels: 0-100 m agl., 100-500 m agl., 500-1000 m agl., 1000-1500 m agl., 1500-2000 m agl., 2000-3000 m agl., and 3000-5000 m agl. These show that potential dust transport pathways have clear seasonal differentiation. The potential transport distance of dust and salt dust is greatest in spring and summer. In autumn and winter, the potential transport of the high-density air trajectory is below 1000 m traveling a shorter distance. Potential dust transport pathways showed notifying directivity in different seasons and heights. Southeast in spring and summer, and north to northeast in autumn and winter are the two main potential transport channels of dust and salt dust. Accordingly, dust and salt dust from the playa of Ebinur Lake may influence the atmospheric processes and biogeochemical cycles of a vast region. The main area of influence of dust and salt dust is close to the source area, and will significantly accelerate the melting of snow and ice in the Tianshan Mountains. This highlights the urgent need to combine remote sensing, isotope and other methods to further research the transport characteristics of dust and salt dust from the playa of the Ebinur Lake.

  4. Mapping compositional and particle size variations across Silver Lake Playa: Relevance to analyses of Mars TIR data

    Science.gov (United States)

    Petroy, S. B.; Arvidson, Raymond E.; Kahle, A. B.

    1991-01-01

    The high spectral and spatial resolution thermal infrared (TIR) data to be acquired from the upcoming Mars Observer-Thermal Emission Spectra (TES) mission will map the composition and texture of the Martian sediments. To prepare for these data, portions of two remote sensing experiments were conducted to test procedures for extracting surface property information from TIR data. Reported here is the continuing analysis of Thermal Infrared Multispectral Scanner (TIMS) data, field emission spectra, laboratory Fourier Transform Infrared (FTIR) reflectance spectra, and field observations with respect to the physical characteristics (composition, emissivity, etc.) of Silver Lake playa in southern California.

  5. Unravelling aquifer-wetland interaction using CSAMT and gravity methods: the Mollina-Camorra aquifer and the Fuente de Piedra playa-lake, southern Spain

    Science.gov (United States)

    Pedrera, A.; Martos-Rosillo, S.; Galindo-Zaldívar, J.; Rodríguez-Rodríguez, M.; Benavente, J.; Martín-Rodríguez, J. F.; Zúñiga-López, M. I.

    2016-06-01

    The hydrological regime of Fuente de Piedra playa-lake (Málaga, southern Spain) has been significantly affected by the intensive exploitation of groundwater in the area. The playa-lake is situated above clays, marls, and gypsum, and under unaltered conditions received surface-subsurface runoff within the watershed as well as groundwater discharge from two carbonate aquifers. We have analyzed the structure of the main one, the Mollina-Camorra carbonate aquifer, by combining controlled source audio magnetotellurics (CSAMT), gravity prospecting, and time-domain electromagnetic (TDEM) soundings. This geophysical information, together with new structural and hydrogeological data, was gathered to develop a new conceptual hydrogeological model. This model allows the hydrological linkage of the carbonate aquifer with the playa-lake system to be established. Moreover, the intensive exploitation in the carbonate aquifer, even outside the watershed of the playa-lake, has affected the hydrological regime of the system. This multidisciplinary work demonstrates the potential of geophysical methods for understanding wetland-aquifer interaction, having important groundwater management implications.

  6. Impact of Diagenesis on Biosignature Preservation Potential in Playa Lake Evaporites in Verde Formation, Arizona: Implications for Mars Exploration

    Science.gov (United States)

    Shkolyar, S.; Farmer, J. D.

    2015-12-01

    Major priorities for Mars science include assessing the preservation potential and impact of diagenesis on biosignature preservation in aqueous sedimentary environments. We address these priorities with field and lab studies of playa evaporites of the Verde Formation (upper Pliocene) in Arizona. Evaporites studied include bottom-nucleated halite and displacive growth gypsum in magnesite-rich mudstone. These lithotypes are potential analogs for ancient lacustrine habitable environments on Mars. This study aimed to understand organic matter preservation potential under different diagenetic histories. Methods combined outcrop-scale field observations and lab analyses, including: (1) thin-section petrography to understand diagenetic processes and paragenesis; (2) X-ray powder diffraction to obtain bulk mineralogy; (3) Raman spectroscopy to identify and place phases (and kerogenous fossil remains) within a microtextural context; (4) Total Organic Carbon (TOC) analyses to estimate weight percentages of preserved organic carbon for each subfacies endmember; and (5) electron microprobe to create 2D kerogen maps semi-quantifying kerogen preservation in each subfacies. Results revealed complex diagenetic histories for each evaporite subfacies and pathways for organic matter preservation. Secondary gypsum grew displacively within primary playa lake mudstones during early diagenesis. Mudstones then experienced cementation by Mg-carbonates. Displacive-growth gypsum was sometimes dissolved, forming crystal molds. These molds were later either infilled by secondary sulfates or recrystallized to gypsum pseudomorphs with minor phases present (i.e., glauberite). These observations helped define taphonomic models for organic matter preservation in each subfacies. This work has the potential to inform in situ target identification, sampling strategies, and data interpretations for future Mars Sample Return missions (e.g., sample caching strategies for NASA's Mars 2020 mission).

  7. Palaeoenvironmental history of Bap-Malar and Kanod playas of western Rajasthan, Thar desert

    Indian Academy of Sciences (India)

    B C Deotare; M D Kajale; S N Rajaguru; S Kusumgar; A J T Jull; J D Donahue

    2004-09-01

    Two playas in the arid core of the western margin of the Thar desert viz., Bap-Malar and Kanod, have been investigated using palynology, geomorphology, archaeology, AMS-radiocarbon dating, stable isotopes, evaporite mineralogy and geoarchaeology. The principal objective was to obtain a reliable lithostratigraphy of the playa sediments. These are about 7m thick in the Bap-Malar and < 2.5 to 3m thick in the Kanod. AMS 14C dates of < 15 ka BP on pollen from sediment layers indicates that the Bap-Malar playa possibly existed even during the LGM. These playas were full of water during the early Holocene (8 ka BP — 5.5 ka BP) and were ephemeral during the Pleistocene- Holocene transition and early to mid to late Holocene. The playas dried almost 1000 years earlier than those occurring on the eastern margin. Pollen of graminaceae, chenopodiaceae / amaranthaceae, cyperaceae etc. and evaporite minerals like gypsum, halite in the profiles indicate that the playas were surrounded by vegetation dominated by grass and that, they remained brackish to saline even during the mid Holocene, lake full stage. Stable dune surfaces, pediments with regoliths, and gravelly channels of ephemeral streams provided a favorable geomorphic niche for nomadic human activity since ∼7 ka BP. Though local ecological factors have played an important role in the evolution of the playas, the winter rains, connected with northwesterly depressions, most likely played a vital role in maintaining these playas.

  8. Braidplain, floodplain and playa lake, alluvial-fan, aeolian and palaeosol facies composing a diversified lithogenetical sequence in the permian and triassic of South Devon (England)

    Science.gov (United States)

    Mader, Detlef

    The Permian and Triassic of South Devon (England) are a continental red bed sequence of very diversified lithogenetical composition. Within the thick series, the distribution of the main depositional environments being fluvial braidplain, fluvial floodplain and playa lake, alluvial fan, aeolian dune and calcrete palaeosol changes repeatedly in both horizontal and vertical direction. Significant sedimentary milieus such as aeolian dunes and calcrete palaeosols occur repeatedly within the succession, but are also lacking in several parts of the sequence. Fluvial braidplain deposits comprise conglomerates, sandstones, intraformational reworking horizons and mudstones and originate in channels and overbank plains of a braided river system. Conglomerates and sandstones are formed by migration of bars and spreading out of sheets during infilling of streams and aggradation of flats. Gravel is often enriched as lag pockets or veneers within steeper scour holes and kolk pots or on the plane floor of the watercourse. Finer-grained sandstones and mudstones are laid down by suspension settling in stagnant water bodies such as small lakes in the overbank area and residual pools in interbar depressions during low-stage or waning-flow in active channels or in abandoned streams. Spectacular bioturbation features in some sandstones with both horizontal tubes and vertical burrows testify to the colonization of the sediments at the bottom of the rivers with declining discharge and transport capacity. Intraformational reworking horizons with ghost-like remnants of degraded sandstones, mudstones and pedogenic carbonates document partially severe condensation of the sequence by removal of some facies elements from the depositional record. The occasionally occurring gravel-bearing mudstones or silty-clayey sandstones represent products of high-energy water surges overspilling the channel banks and transporting sandy and gravelly bed-load in limited amounts beyond the levee wall. The

  9. Investigation into avian mortality in the Playa Lakes region of southeastern New Mexico: Final Report - June 1997

    Science.gov (United States)

    Dein, F. Joshua; Baeten, Laurie A.; Moore, Melody K.; Samuel, Michael D.; Miller, Paul D.; Murphy, Christopher; Sissler, Steven; Jeske, Clinton W.; Jehl, Joseph R.; Yaeger, J. S.; Bauer, B.; Mahoney, Shiela A.

    1997-01-01

    This Final Report is a review of work on a cooperative study undertaken by the USGS Biological Resources Division's National Wildlife Health Center (NWHC) and National Wetlands Research Center (NWRC; formerly the Southern Science Center) from 1994 through 1997. The study was initiated at the request of the Bureau of Land Management (BLM), through a request to the former National Biological Service. The Southeastern New Mexico Playa Lakes Coordinating Committee (SENMPLCC) played an important role in outlining the research needs. The initial Study Plan document, which outlines the background, objectives and methods for the first two years is available as Appendix 1. A letter indicating modifications to the Study Plan was sent to the SENMPLCC chair on April 25,1995, and is Appendix 2. An Interim Report, covering this work was completed and submitted in September 1995. The Literature Review section of the study was completed and presented to SENMPLCC in August, 1995. Following SENMPLCC review, NWHC was asked to develop a series of questions that could be posed from information gained in the initial phase (Appendix 3). The NWHC and NWRC were then directed to begin work to answer the top three questions, within the available fiscal resources. NWRC could continue with work outlined under the original Study Plan (Appendix 1), however an additional Study Plan for experiments performed by NWHC and collaborators and is available as Appendix 4.

  10. Interstitial brines in playa sediments

    Science.gov (United States)

    Jones, B.F.; Van Denburgh, A.S.; Truesdell, A.H.; Rettig, S.L.

    1969-01-01

    Study of several closed drainages in the Great Basin has shown that the interstitial solutions of shallow, fine-grained playa deposits store a large quantity of dissolved solids and are often more concentrated than associated lakes and ponds, except in peripheral zones of stream or ground-water inflow. These interstitial fluids, when compared with local runoff, impoundments, or spring waters, commonly have a distinctive ionic composition which sometimes cannot be explained by either simple mixing of surface and subsurface inflow or by evaporative concentration. At Abert Lake, Oregon, the interstitial solute concentrations increased with depth to values as much as five times greater than the lake, except where springs indicate significant ground-water input. Where Na+, Cl, and CO2 species constitute more than 90% of the solutes, Na+ Cl- ratios in the lake water are lower than in interstitial solutions of bottom cores and higher than in playa fluids. At the same time, Na+ K+ ratios are highest in the fluids of lake bottom muds and lowest in playa interstitials. In deeper playa profiles, interstitial Na+ Cl- tended to decrease with depth (5 ft. maximum). In the Abert Lake area, as in other parts of the western Great Basin, Na+ Cl- ratios are indicative of total CO2 in solution and the effects of organic decay in surficial sediments. These ratios, coupled with data on silica and bulk density, show that higher PCO2 accompanying decay promotes silicate dissolution and hydrogen ion exchange, stripping alkalis from sediment which had preferentially adsorbed K+ when entering the lake. On subsequent loss of pore fluid in the playa regime, silica initially released to solution in the lake environment is readsorbed on dissolution products. ?? 1969.

  11. Flood-hazard study: 100-year flood stage for Lucerne Lake, San Bernadino County, California

    Science.gov (United States)

    Busby, Mark William

    1977-01-01

    A study of the flood hydrology of Lucerne Valley, Calif., was made to develop the 100-year stage for Lucerne Lake. Synthetic-hydrologic techniques were used; and the 100-year flood stage was estimated to be at an elevation of 2,849.3 feet above mean sea level. Channel dimensions were measured at 59 sites in Lucerne Valley. Dranage area-discharge relations developed from channel-geometry data for sites nearby were used to estimate the discharge at 12 additional sites where channel geometry could not be measured. In order to compute the total volume discharge into the playa, the peak discharges were converted to volumes. From the Apple Valley report (Busby, 1975) the equation formulated from the relation between peak discharge and flood volume for the deserts of California was used to compute the flood volumes for routing into Lucerne Lake. (Woodard-USGS)

  12. Kansas Playa Wetlands

    Data.gov (United States)

    Kansas Data Access and Support Center — This digital dataset provides information about the distribution, areal extent, and morphometry of playa wetlands throughout western Kansas. Playa wetlands were...

  13. Playas Accesibles

    OpenAIRE

    Espol; Valencia Iglesias, Sabrina; Ramirez Iñiguez, Karla; Garcia Desintonio, Mariela

    2015-01-01

    La presente tesis, tiene por objetivo el determinar si el Proyecto Palyas Accesibles es viable o no, proyectos que està enfocado en crear accesibilidad en la playa de ayangue para las personas discapacitadas, para esto, se ha desarrollado varias herramientas desde la òptica social y tècnica es asì, que tiene un anàlisis sigiendo la metodologìa de Marco Lògico a fin de identificarse actores, interesados y establecer los objetivos claros basados en el àrbol de problemas y objetivos establecido...

  14. Grass buffers for playas in agricultural landscapes: An annotated bibliography

    Science.gov (United States)

    Melcher, Cynthia P.; Skagen, Susan K.

    2005-01-01

    This bibliography and associated literature synthesis (Melcher and Skagen, 2005) was developed for the Playa Lakes Joint Venture (PLJV). The PLJV sought compilation and annotation of the literature on grass buffers for protecting playas from runoff containing sediments, nutrients, pesticides, and other contaminants. In addition, PLJV sought information regarding the extent to which buffers may attenuate the precipitation runoff needed to fill playas, and avian use of buffers. We emphasize grass buffers, but we also provide information on other buffer types.

  15. Physical, chemical, and mineralogical data from surficial deposits, groundwater levels, and water composition in the area of Franklin Lake playa and Ash Meadows, California and Nevada

    Science.gov (United States)

    Goldstein, Harland L.; Breit, George N.; Yount, James C.; Reynolds, Richard L.; Reheis, Marith C.; Skipp, Gary L.; Fisher, Eric M.; Lamothe, Paul J.

    2011-01-01

    This report presents data and describes the methods used to determine the physical attributes, as well as the chemical and mineralogical composition of surficial deposits; groundwater levels; and water composition in the area of Franklin Lake playa and Ash Meadows, California and Nevada. The results support studies that examine (1) the interaction between groundwater and the ground surface, and the transport of solutes through the unsaturated zone; (2) the potential for the accumulation of metals and metalloids in surface crusts; (3) emission of dust from metal-rich salt crust; and (4) the effects of metal-rich dusts on human and ecosystem health. The evaporation of shallow (salt in the subsurface and (or) the formation of salt crusts at the ground surface. Ground-surface characteristics such as hardness, electrical conductivity, and mineralogy depend on the types and forms of these salt crusts. In the study area, salt crusts range from hard and bedded to soft and loose (Reynolds and others, 2009). Depending on various factors such as the depth and composition of groundwater and sediment characteristics of the unsaturated zone, salt crusts may accumulate relatively high contents of trace elements. Soft, loose salt crusts are highly vulnerable to wind erosion and transport. These vulnerable crusts, which may contain high contents of potentially toxic trace elements, can travel as atmospheric dust and affect human and ecosystem health at local to regional scales.

  16. The chemistry of playa-lake-sediments as a tool for the reconstruction of Holocene environmental conditions - a case study from the central Ebro basin

    Science.gov (United States)

    Schütt, Brigitta

    The focus of the presented study is the reconstruction of the Holocene limnic and drainage basin conditions of the Laguna de Jabonera, a today playa-lake-system in the Desierto de Calanda, central Ebro Basin, using the inorganic characters of the lacustrine sediments. Mineralogical fabric helped to reconstruct the overall geomorphic processes and gives clues to the synsedimentary limnic environment (paleosalinity). The chemical composition of the lacustrine sediments largely reflects the mineralogical composition, but the higher resolution of the geochemical data compared to the mineralogical data enables to stratigraphically split the extracted core profile into three stratigraphic units. Supplementally, it is demonstrated that Statistics between chemical compounds point to the synsedimentary intensity of weathering and soil forming processes. As for the lacustrine sediments investigated there are no data yet available a preliminary chronological framework is derived by comparison with results from neighbouring areas. Based on this the hypothesis is put forward that during the socalled Little Ice Age subhumid to dry-subhumid environmental conditions occurred. Also possibly during the late Subboreal distinct wetter environmental conditions than today prevailed. Additionally, it is demonstrated that in the most recent past human impact is causing increased erosion rates and, thus, increased deposition of detritals in the most recent lacustrine sediments.

  17. Grass buffers for playas in agricultural landscapes: A literature synthesis

    Science.gov (United States)

    Melcher, Cynthia P.; Skagen, Susan K.

    2005-01-01

    We summarize current knowledge about grass buffers for protecting small, isolated wetlands in agricultural contexts, including information relevant to protecting playas from runoff containing sediments, nutrients, pesticides, and other contaminants, and information on how buffers may affect densities and productivity of grassland birds. Land-uses surrounding the approximately 60,000 playas within the Playa Lakes Region (PLR), including intensive agriculture, feedlots, and oil extraction, can contribute to severe degradation of playas. Farming and grazing can lead to significant sedimentation in nearby playas, eliminating their ability to hold water, support the region’s biodiversity, or adequately recharge aquifers. Contaminants further degrade habitats and threaten the water quality of underlying aquifers, including the Ogallala Aquifer.

  18. Dust emission from wet and dry playas in the Mojave Desert, USA

    Science.gov (United States)

    Reynolds, R.L.; Yount, J.C.; Reheis, M.; Goldstein, H.; Chavez, P.; Fulton, R.; Whitney, J.; Fuller, C.; Forester, R.M.

    2007-01-01

    The interactions between playa hydrology and playa-surface sediments are important factors that control the type and amount of dust emitted from playas as a result of wind erosion. The production of evaporite minerals during evaporative loss of near-surface ground water results in both the creation and maintenance of several centimeters or more of loose sediment on and near the surfaces of wet playas. Observations that characterize the texture, mineralogic composition and hardness of playa surfaces at Franklin Lake, Soda Lake and West Cronese Lake playas in the Mojave Desert (California), along with imaging of dust emission using automated digital photography, indicate that these kinds of surface sediment are highly susceptible to dust emission. The surfaces of wet playas are dynamic - surface texture and sediment availability to wind erosion change rapidly, primarily in response to fluctuations in water-table depth, rainfall and rates of evaporation. In contrast, dry playas are characterized by ground water at depth. Consequently, dry playas commonly have hard surfaces that produce little or no dust if undisturbed except for transient silt and clay deposited on surfaces by wind and water. Although not the dominant type of global dust, salt-rich dusts from wet playas may be important with respect to radiative properties of dust plumes, atmospheric chemistry, windborne nutrients and human health.

  19. Astronomy of Nabta Playa

    Science.gov (United States)

    McK Mahille, J.; Schild, R.; Wendorf, F.; Brenmer, R.

    2007-07-01

    The repetitive orientation of megaliths, human burials, and cattle burials toward the northern regions of the sky reveals a very early symbolic connection to the heavens at Nabta Playa, Egypt. The groups of shaped stones facing north may have represented spirits of individuals who died on the trail or locally. A second piece of evidence for astronomy at Nabta Playa is the stone circle with its two sightlines toward the north and toward the rising sun at the June solstice. Finally, the five alignments of megaliths, which were oriented to bright stars in the fifth millennium, suggest an even more careful attention to the heavens. The "empty tombs" and deeply buried table rocks of the Complex Structures provide some of the greatest enigmas of Nabta Playa. The recurrent symbolism of the ceremonial centre involves issues that would have been of both practical and symbolic importance to the nomads: death, water, cattle, sun, and stars.

  20. Hydraulic gradient and dust emissivity along a playa to distal fan transect

    Science.gov (United States)

    Caldwell, T. G.; Sweeney, M.; Bacon, S. N.; McDonald, E.

    2009-12-01

    Distal alluvial fans along the margins of playas in the desert southwest, as well as the playas themselves, are subjected to severe temporal changes in groundwater levels. Soil moisture decreases with elevation above the playa floor where groundwater levels control both soil moisture and salinity. A series of measurements were conducted along transects of a wet playa (Soda Lake, California) and a dry playa (Silver Lake; California) to quantify changes in PM10) emissions, in addition to soil physical and chemical properties. The relatively high moisture content at the playa surface of Soda Lake is controlled by a perennial shallow ground water system that promotes the precipitation and wicking of evaporates and the formation of soluble salt crusts. In contrast, Silver Lake playa is underlain by a deep ground water system, therefore the playa surface remains dry throughout the year, except for unseasonably wet winters when flooding occurs of the playa surface during inundation events. Measurements were taken along linear transects across a diverse range of playa features ranging from the playa floor to distal fans using the Portable In-Situ Wind Erosion Lab (PI-SWERL), electromagnetic induction, and soil sampling. Results indicate that dust emissivity of undisturbed soils at a friction velocity (u*) of 0.56 m s-1 increases substantially at the playa fringe (3.53 ± 1.44 mg m-2 s-1) compared to the relatively higher distal alluvial fans (0.13 ± 0.08 mg m-2 s-1) and lower emission on the playa surfaces of either the silt crust of Silver Lake playa (fans. The area between these landforms, the silt-rich playa fringe, is subjected to transient groundwater and surface water influx resulting in monovalent bicarbonate (HCO3-) salts which disperse clays and creates an area of high emissivity. As distance to groundwater increases, the hydraulic gradient shifts from the upward evaporation of saline groundwater to downward flushing by dilute precipitation. This shift results in

  1. Water-Quality and Lake-Stage Data for Wisconsin Lakes, Water Year 2007

    Science.gov (United States)

    Wisconsin Water Science Center Lake-Studies Team: Rose, W. J.; Garn, H.S.; Goddard, G.L.; Marsh, S.B.; Olson, D.L.; Robertson, D.M.

    2008-01-01

    The U.S. Geological Survey (USGS), in cooperation with local and other agencies, collects data at selected lakes throughout Wisconsin. These data, accumulated over many years, provide a data base for developing an improved understanding of the water quality of lakes. To make these data available to interested parties outside the USGS, the data are published annually in this report series. The locations of water-quality and lake-stage stations in Wisconsin for water year 2007 are shown in figure 1. A water year is the 12-month period from October 1 through September 30. It is designated by the calendar year in which it ends. Thus, the period October 1, 2005 through September 30, 2007 is called 'water year 2007.' The purpose of this report is to provide information about the chemical and physical characteristics of Wisconsin lakes. Data that have been collected at specific lakes, and information to aid in the interpretation of those data, are included in this report. Data collected include measurements of in-lake water quality and lake stage. Time series of Secchi depths, surface total phosphorus and chlorophyll a concentrations collected during non-frozen periods are included for all lakes. Graphs of vertical profiles of temperature, dissolved oxygen, pH, and specific conductance are included for sites where these parameters were measured. Descriptive information for each lake includes: location of the lake, area of the lake?s watershed, period for which data are available, revisions to previously published records, and pertinent remarks. Additional data, such as streamflow and water quality in tributary and outlet streams of some of the lakes, are published in another volume: 'Water Resources Data-Wisconsin, 2007.'

  2. Water-quality and lake-stage data for Wisconsin lakes, water year 2005

    Science.gov (United States)

    Rose, W.J.; Garn, H.S.; Goddard, G.L.; Marsh, S.B.; Olson, D.L.; Robertson, D.M.

    2006-01-01

    The U.S. Geological Survey (USGS), in cooperation with local and other agencies, collects data at selected lakes throughout Wisconsin. These data, accumulated over many years, provide a data base for developing an improved understanding of the water quality of lakes. The purpose of this report is to provide information about the chemical and physical charac-teristics of Wisconsin lakes. Data that have been collected at specific lakes, and information to aid in the interpretation of those data, are included in this report. Data collected include measure-ments of in-lake water quality and lake stage. Time series graphs of Secchi depths, surface total phosphorus and chlorophyll a concentrations collected during non-frozen periods are included for all lakes. Graphs of vertical profiles of temperature, dissolved oxygen, pH, and specific conductance are included for sites where these parameters were measured. Descriptive infor-mation for each lake includes: location of the lake, area of the lake's watershed, period for which data are available, revisions to previously published records, and pertinent remarks.

  3. Evaporation from groundwater discharge playas, Estancia Basin, central New Mexico

    Science.gov (United States)

    Menking, Kirsten M.; Anderson, Roger Y.; Brunsell, Nathaniel A.; Allen, Bruce D.; Ellwein, Amy L.; Loveland, Thomas A.; Hostetler, Steven W.

    2000-07-01

    Bowen ratio meteorological stations have been deployed to measure rates of evaporation from groundwater discharge playas and from an adjacent vegetated bench in the Estancia Basin, in central New Mexico. The playas are remnants of late Pleistocene pluvial Lake Estancia and are discharge areas for groundwater originating as precipitation in the adjacent Manzano Mts. They also accumulate water during local precipitation events. Evaporation is calculated from measured values of net radiation, soil heat flux, atmospheric temperature, and relative humidity. Evaporation rates are strongly dependent on the presence or absence of standing water in the playas, with rates increasing more than 600% after individual rainstorms. Evaporation at site E-12, in the southeastern part of the playa complex, measured 74 cm over a yearlong period from mid-1997 through mid-1998. This value compares favorably to earlier estimates from northern Estancia playas, but is nearly three times greater than evaporation at a similar playa in western Utah. Differences in geographical position, salt crust composition, and physical properties may explain some of the difference in evaporation rates in these two geographic regions.

  4. Comments on Racetrack playa: Rocks moved by wind alone

    Science.gov (United States)

    Sanz-Montero, M. E.; Cabestrero, Ó.; Rodríguez-Aranda, J. P.

    2016-03-01

    The mechanisms by which rocks move across the beds of playa lakes leaving tracks continue to be debated (Sanz-Montero and Rodríguez-Aranda, 2013; Norris et al., 2014; Sanz-Montero et al., 2015a,b; Baumgardner and Shaffer, 2015; Jones and Hooke, 2015). In this regard, the article by Jones and Hooke (Aeolian Research 19, 2015) is particularly interesting since it provides a description of these mechanisms by R. Jones who, during a storm event in 1972, was probably the first person to witness movement of rocks. The dominant meteorological conditions described by Jones during the period when the tracks were formed are, significantly, rather similar to those previously described by Clements (1952) at Little Bonnie Claire Playa (Nevada, USA). The storm conditions referred to in the article also coincide with the observations, measurements and deductions made by Sanz-Montero and Rodríguez-Aranda (2013) and Sanz-Montero et al. (2015a,b) at Altillo Chica playa lake, Central Spain. Furthermore, we were able to carry out an on-site analysis of the sedimentary structures at Racetrack playa in June 2015, allowing us to verify the similarity of the features present at both sites. Together with the important role played by gusty winds in the formation of the tracks, all the above mentioned studies point to the presence of a thin veneer of water, just a few millimeters deep, in the area of the playa lake where the rock movements occur. However, Jones and Hooke (2015) disregard the force exerted by moving water and analyze the coefficient of friction assuming that the rocks are moved by wind alone. We offer an alternative explanation for the movement of rocks both at Racetrack and Altillo Chica playa lake which considers not only the wind but also the role played by moving water in conjunction with other parameters which modify the erosion thresholds (rocks acting as obstacles) and reduce friction (benthic microorganisms).

  5. Water-Quality and Lake-Stage Data for Wisconsin Lakes, Water Year 2006

    Science.gov (United States)

    Rose, W.J.; Garn, H.S.; Goddard, G.L.; Marsh, S.B.; Olson, D.L.; Robertson, D.M.

    2007-01-01

    The U.S. Geological Survey (USGS), in cooperation with local and other agencies, collects data at selected lakes throughout Wisconsin. These data, accumulated over many years, provide a data base for developing an improved understanding of the water quality of lakes. To make these data available to interested parties outside the USGS, the data are published annually in this report series. The locations of water-quality and lake-stage stations in Wisconsin for water year 2006 are shown in figure 1. A water year is the 12-month period from October 1 through September 30. It is designated by the calendar year in which it ends. Thus, the period October 1, 2005 through September 30, 2006 is called 'water year 2006.' The purpose of this report is to provide information about the chemical and physical characteristics of Wisconsin lakes. Data that have been collected at specific lakes, and information to aid in the interpretation of those data, are included in this report. Data collected include measurements of in-lake water quality and lake stage. Time series of Secchi depths, surface total phosphorus and chlorophyll a concentrations collected during non-frozen periods are included for all lakes. Graphs of vertical profiles of temperature, dissolved oxygen, pH, and specific conductance are included for sites where these parameters were measured. Descriptive information for each lake includes: location of the lake, area of the lake's watershed, period for which data are available, revisions to previously published records, and pertinent remarks. Additional data, such as streamflow and water quality in tributary and outlet streams of some of the lakes, are published in another volume: 'Water Resources Data-Wisconsin, 2006.' Water-resources data, including stage and discharge data at most streamflow-gaging stations, are available through the World Wide Web on the Internet. The Wisconsin Water Science Center's home page is at http://wi.water.usgs.gov/. Information on the

  6. Water-quality and lake-stage data for Wisconsin lakes, water year 2014

    Science.gov (United States)

    Manteufel, S. Bridgett; Robertson, Dale M.

    2017-05-25

    IntroductionThe U.S. Geological Survey (USGS), in cooperation with local and other agencies, collects data at selected lakes throughout Wisconsin. These data, accumulated over many years, provide a database for developing an improved understanding of the water quality of lakes. To make these data available to interested parties outside the USGS, the data are published annually in this report series. The locations of water-quality and lake-stage stations in Wisconsin for water year 2014 are shown in figure 1. A water year is the 12-month period from October 1 through September 30. It is designated by the calendar year in which it ends. Thus, the periodOctober 1, 2013, through September 30, 2014, is called “water year 2014.”The purpose of this report is to provide information about the chemical and physical characteristics of Wisconsin lakes. Data that have been collected at specific lakes, and information to aid in the interpretation of those data, are included in this report. Data collected include measurements of in-lake water quality and lake stage. Time series of Secchi depths, surface total phosphorus, and chlorophyll a concentrations collected during nonfrozen periods are included for many lakes. Graphs of vertical profiles of temperature, dissolved oxygen, pH, and specific conductance are included for sites where these parameters were measured. Descriptive information for each lake includes the location of the lake, area of the lake’s watershed, period for which data are available, revisions to previously published records, and pertinent remarks. Additional data, such as streamflow and water quality in tributary and outlet streams of some of the lakes, are published online at http://nwis.waterdata.usgs.gov/wi/nwis.Water-resources data, including stage and discharge data at most streamflow-gaging stations, are available online. The Wisconsin Water Science Center’s home page is at https://www.usgs.gov/centers/wisconsin-water-science-center. Information

  7. Water-quality and lake-stage data for Wisconsin lakes, water years 2012–2013

    Science.gov (United States)

    Manteufel, S. Bridgett; Robertson, Dale M.

    2017-05-25

    IntroductionThe U.S. Geological Survey (USGS), in cooperation with local and other agencies, collects data at selected lakes throughout Wisconsin. These data, accumulated over many years, provide a data base for developing an improved understanding of the water quality of lakes. To make these data available to interested parties outside the USGS, the data are published annually in this report series. The locations of water-quality and lake-stage stations in Wisconsin for water year 2012 are shown in figure 1. A water year is the 12-month period from October 1 through September 30. It is designated by the calendar year in which it ends. Thus, the period October 1, 2011 through September 30, 2012, is called “water year 2012.”The purpose of this report is to provide information about the chemical and physical characteristics of Wisconsin lakes. Data that have been collected at specific lakes, and information to aid in the interpretation of those data, are included in this report. Data collected include measurements of in-lake water quality and lake stage. Time series of Secchi depths, surface total phosphorus and chlorophyll a concentrations collected during non-frozen periods are included for all lakes. Graphs of vertical profiles of temperature, dissolved oxygen, pH, and specific conductance are included for sites where these parameters were measured. Descriptive information for each lake includes: location of the lake, area of the lake’s watershed, period for which data are available, revisions to previously published records, and pertinent remarks. Additional data, such as streamflow and water quality in tributary and outlet streams of some of the lakes, are published online at http://nwis.waterdata.usgs.gov/wi/nwis.Water-resources data, including stage and discharge data at most streamflow-gaging stations, are available online. The Wisconsin Water Science Center’s home page is at https://www.usgs.gov/centers/wisconsin-water-science-center. Information on

  8. Recharge Rates and Chemistry Beneath Playas of the High Plains Aquifer - A Literature Review and Synthesis

    Science.gov (United States)

    Gurdak, Jason J.; Roe, Cassia D.

    2009-01-01

    Playas are ephemeral, closed-basin wetlands that are important zones of recharge to the High Plains (or Ogallala) aquifer and critical habitat for birds and other wildlife in the otherwise semiarid, shortgrass prairie and agricultural landscape. The ephemeral nature of playas, low regional recharge rates, and a strong reliance on ground water from the High Plains aquifer has prompted many questions regarding the contribution of recharge from playas to the regional aquifer. To address these questions and concerns, the U.S. Geological Survey, in cooperation with the Playa Lakes Joint Venture, present a review and synthesis of the more than 175 publications about recharge rates and chemistry beneath playas and interplaya settings. Although a number of questions remain regarding the controls on recharge rates and chemistry beneath playas, the results from most published studies indicate that recharge rates beneath playas are substantially (1 to 2 orders of magnitude) higher than recharge rates beneath interplaya settings. The synthesis presented here supports the conceptual model that playas are important zones of recharge to the High Plains aquifer and are not strictly evaporative pans. The major findings of this synthesis yield science-based implications for the protection and management of playas and ground-water resources of the High Plains aquifer and directions for future research.

  9. Water-quality and lake-stage data for Wisconsin lakes, water years 2008−2011

    Science.gov (United States)

    Manteufel, S. Bridgett; Olson, Daniel L.; Robertson, Dale M.; Goddard, Gerald L.

    2016-09-30

    The U.S. Geological Survey (USGS), in cooperation with local and other agencies, collects data at selected lakes throughout Wisconsin. These data, accumulated over many years, provide a data base for developing an improved understanding of the water quality of lakes. To make these data available to interested parties outside the USGS, the data are published annually in this report series.The purpose of this report is to provide information about the chemical and physical characteristics of Wisconsin lakes during water years 2008–2011. A water year is the 12-month period from October 1 through September 30. It is designated by the calendar year in which it ends. Thus, the period October 1, 2007 through September 30, 2008 is called "water year 2008." Data that have been collected at specific lakes, and information to aid in the interpretation of those data, are presented in this report for water years from 2008–2011. Data collected include measurements of in-lake water quality and lake stage. Time series of Secchi depths, surface total phosphorus and chlorophyll a concentrations collected during non-frozen periods are included for all lakes. Graphs of vertical profiles of temperature, dissolved oxygen, pH, and specific conductance are included for sites where these parameters were measured. Descriptive information for each lake includes: location of the lake, area of the lake’s watershed, period for which data are available, revisions to previously published records, and pertinent remarks. Additional data, such as streamflow and water quality in tributary and outlet streams of some of the lakes, are available via the "USGS Annual Water Data Report" Web site: http://wdr.water.usgs.gov/.

  10. Palaeolimnological evidence of vulnerability of Lake Neusiedl (Austria) toward climate related changes since the last "vanished-lake" stage.

    Science.gov (United States)

    Tolotti, Monica; Milan, Manuela; Boscaini, Adriano; Soja, Gerhard; Herzig, Alois

    2013-04-01

    The palaeolimnological reconstruction of secular evolution of Euroepan Lakes with key socio-economical relevance respect to large (climate change) and local scale (land use, tourism) environmental changes, represents one of the objectives of the project EuLakes (European Lakes Under Environmental Stressors, Supporting lake governance to mitigate the impact of climate change, Reg. N. 2CE243P3), launched in 2010 within the Central European Inititiative. The project consortium comprises lakes of different morphology and prevalent human uses, including the meso-eutrophic Lake Neusiedl, the largest Austrian lake (total area 315 km2), and the westernmost shallow (mean depth 1.2 m) steppe lake of the Euro-Asiatic continent. The volume of Lake Neusiedl can potentially change over the years, in relation with changing balance between atmospheric precipitation and lake water evapotranspiration. Changing water budget, together with high lake salinity and turbidity, have important implications over the lake ecosystem. This contribution illustrates results of the multi-proxi palaeolimnological reconstruction of ecologial changes occurred in Lake Neusiedl during the last ca. 140 years, i.e. since the end of the last "vanished-lake" stage (1865-1871). Geochemical and biological proxies anticipate the increase in lake productivity of ca. 10 years (1950s) respect to what reported in the literature. Diatom species composition indicate a biological lake recovery in the late 1980s, and suggest a second increment in lake productivity since the late 1990s, possibly in relation with the progressive increase in the nitrogen input from agriculture. Abundance of diatoms typical of brackish waters indicated no significant long-term change in lake salinity, while variations in species toleranting dessiccation confirm the vulnerability of Lake Neusiedl toward climate-driven changes in the lake water balance. This fragility is aggravated by the the semi-arid climate conditions of the catchemnt

  11. Deposition and early diagenesis of playa glauberite in the Karinga Creek drainage system, Northern Territory, Australia

    Science.gov (United States)

    Arakel, A. V.; Cohen, A.

    1991-02-01

    Glauberite [Na 2Ca(SO 4) 2], in the form of discrete crystals, nodules and lenses, represents the second most common sulphate mineral type (after gypsum) in the chain of modern playa lakes located in the Karinga Creek drainage system, Northern Territory. These modern glauberite deposits exhibit textures and fabrics which reflect both syndeposition with gypsum within the playa phreatic zone, and early diagenetic replacement of host gypsite in the playa vadose zone. Because the distribution of hydrological zones in individual playa lakes vary significantly, the extent of glauberite facies development is highly irregular. Factors controlling glauberite deposition include the nature and extent of groundwater discharge from local and regional aquifers, playa surface evaporation rates, porewater geochemistry and the depth to basal aquicludes. Geochemical and petrographic evidence indicate that the paragenesis of sulphate minerals in the playa lakes of the study area is primarily dictated by the solubility of gypsum, which in turn reflects the extent of dilution and concentration of playa porewaters. On a regional scale, brine dilution and concentration can be related to seasonal and longer-term groundwater recharge-discharge patterns; but, on a local scale, the proximity to springs and ephemeral seepage creeks emanating from local calcrete aquifers is the dominating influence. Hence, a thorough knowledge of groundwater hydrodynamics, particularly the recharge-discharge pattern in playa-marginal areas, must be an essential part of any detailed assessment of the role of depositional and early diagenetic processes in the genesis of glauberite facies in similar arid drainage basins. The close relationship between glauberite facies development and the playa groundwater level has significant implications for interpretations of variation in the water table and other environmental conditions in the shallowing-upwards sequences of ancient lacustrine deposits. The presence of

  12. Playa: High-Performance Programmable Linear Algebra

    Directory of Open Access Journals (Sweden)

    Victoria E. Howle

    2012-01-01

    Full Text Available This paper introduces Playa, a high-level user interface layer for composing algorithms for complex multiphysics problems out of objects from other Trilinos packages. Among other features, Playa provides very high-performance overloaded operators implemented through an expression template mechanism. In this paper, we give an overview of the central Playa objects from a user's perspective, show application to a sequence of increasingly complex solver algorithms, provide timing results for Playa's overloaded operators and other functions, and briefly survey some of the implementation issues involved.

  13. Water-quality and Llake-stage data for Wisconsin Lakes, Water Year 2004

    Science.gov (United States)

    Rose, W.J.; Garn, H.S.; Goddard, G.L.; Marsh, S.B.; Olson, D.L.; Robertson, D.M.

    2005-01-01

    The U.S. Geological Survey (USGS), in cooperation with local and other agencies, collects data at selected lakes throughout Wisconsin. These data, accumulated over many years, provide a data base for developing an improved understanding of the water quality of lakes. To make these data available to interested parties outside the USGS, the data are published annually in this report series. The locations of water-quality and lake-stage stations in Wisconsin for water year 2004 are shown in figure 1. A water year is the 12-month period from October 1 through September 30. It is designated by the calendar year in which it ends. Thus, the period October 1, 2003 through September 30, 2004 is called 'water year 2004.' The purpose of this report is to provide information about the chemical and physical characteristics of Wisconsin lakes. Data that have been collected at specific lakes, and information to aid in the interpretation of those data, are included in this report. Data collected include measurements of in-lake water quality and lake stage. Time series of Secchi depths, surface total phosphorus and chlorophyll a concentrations collected during non-frozen periods are included for all lakes. Graphs of vertical profiles of temperature, dissolved oxygen, pH, and specific conductance are included for sites where these parameters were measured. Descriptive information for each lake includes: location of the lake, area of the lake's watershed, period for which data are available, revisions to previously published records, and pertinent remarks. Additional data, such as streamflow and water quality in tributary and outlet streams of some of the lakes, are published in another volume: 'Water Resources Data-Wisconsin, 2004.' Water-resources data, including stage and discharge data at most streamflow-gaging stations, are available throught the World Wide Web on the Internet. The Wisconsin Water Science Center's home page is at http://wi.water.usgs.gov/. Information on the

  14. Astronomy at Nabta Playa, Southern Egypt

    Science.gov (United States)

    McKim Malville, J.

    Nabta Playa may contain the oldest human-made features with astronomical alignments in Egypt. In the Late and Terminal Neolithic (7,500-5,400 BP), nomadic pastoralists built a ceremonial center on the western shore of Nabta Playa, consisting of some 30 complex megalithic structures, stone circles, and lines of megaliths crossing the playa. The megaliths may once have aligned with Arcturus, the Belt of Orion, Sirius, and α Cen. Reorientations of the northern set of megaliths suggest a response to precession. Elaborate burials at the nearby cemetery at Gebel Ramlah indicate the nomads consisted of Mediterranean and sub-Saharan populations with little social stratification.

  15. The Ancylus Lake stage of the Baltic Sea in Fehmarn Belt: Indications of a new threshold?

    Science.gov (United States)

    Feldens, Peter; Schwarzer, Klaus

    2012-03-01

    The Baltic Ice Lake, Yoldia Sea, Ancylus Lake and Littorina Sea stages of regression and transgression controlled the history of the Baltic Sea since the last glacial period. Many details regarding their development remain unknown, including the question whether the regression of the Ancylus Lake (between 10,700 and 10,200 cal yr BP) took place west of the Darss Sill, or elsewhere. This study addresses whether a drowned river system in Fehmarn Belt (SW Baltic Sea) can be related to the drainage of the Ancylus Lake. The river channel is cut into glacial till in the western part of Fehmarn Belt. Here, the channel reaches an incision depth of up to 12 m at a base level of 40 m b.s.l. (below sea level). Near Mecklenburg Bay, the buried channel is incised down to 60 m b.s.l. and widens rapidly from several hundred meters to more than 1 km, fading towards east. It was mainly shaped as part of a glacial meltwater system at a maximum water level of 30 m b.s.l., and is therefore not related to the Ancylus Lake drainage. During the lowstand of the Baltic Ice Lake, local shallow water bodies covered the study area. A previously reported westward directed drainage of a lake in the eastern Fehmarn Belt could be restricted to a time interval between the highstand of the Ancylus Lake and prior to the Littorina Transgression. Timing, water level and potential water discharge of this event suggest a connection to a partial drainage of the Ancylus Lake. It is concluded that the threshold separating the Ancylus Lake from the North Sea needs to be located west of Fehmarn Belt.

  16. Saline Playas on Qinghai-Tibet Plateau as Mars Analog for the Formation-Preservation of Hydrous Salts and Biosignatures

    Science.gov (United States)

    Wang, A.; Zheng, M.; Kong, F.; Sobron, P.; Mayer, D. P.

    2010-12-01

    Qinghai-Tibet (QT) Plateau has the highest average elevation on Earth (~ 4500 m, about 50-60% of atmospheric pressure at sea-level). The high elevation induces a tremendous diurnal (and seasonal) temperature swing caused by high level of solar irradiation during the day and low level of atmospheric insulation during the evening. In addition, the Himalaya mountain chain (average height >6100 m) in the south of the QT Plateau largely blocks the pathway of humid air from the Indian Ocean, and produces a Hyperarid region (Aridity Index, AI ~ 0.04), the Qaidam Basin (N32-35, E90-100) at the north edge of the QT Plateau. Climatically, the low P, T, large ΔT, high aridity, and high UV radiation all make the Qaidam basin to be one of the most similar places on Earth to Mars. Qaidam basin has the most ancient playas (up to Eocene) and the lakes with the highest salinity on QT Plateau. More importantly, Mg-sulfates appear in the evaporative salts within the most ancient playas (Da Langtang) at the northwest corner of Qaidam basin, which mark the final stage of the evaporation sequence of brines rich in K, Na, Ca, Mg, Fe, C, B, S, and Cl. The evaporation minerals in the saline playas of Qaidam basin, their alteration and preservation under hyperarid conditions can be an interesting analog for the study of Martian salts and salty regolith. We conducted a field investigation at Da Langtan playa in Qaidam basin, with combined remote sensing (ASTER on board of NASA’s Terra satellite, 1.656, 2.167, 2.209, 2.62, 2.336, 2.40 µm), in situ sensing of a portable NIR spectrometer (WIR, 1.25-2.5 µm continuous spectral range), and the laboratory analyses of collected samples from the field (ASD spectrometer, 0.4 -2.5 µm, and Laser Raman spectroscopy). The results indicate that the materials contributing the high albedo layers in playa deposits are carbonate-gypsum-bearing surface soils, salt-clay-bearing exhaumed Pleistocene deposits, dehydrated Na-sulfates, hydrous Mg

  17. Satellite Imagery Measures of the Astronomically Aligned Megalithis at Nabta Playa.

    Science.gov (United States)

    Brophy, T.; Rosen, P.

    The Nabta Playa megalithic complex consists of two types of features: first are the large stones, many of them shaped, placed on or in the sediments of an ancient seasonal lake bed that is now hyper-ariad, second are large sculpted bedrocks features underneath the sediments and associated with the surface megaliths (Wendorf et al. 1992). The astronomically aligned surface megalithic structures described in field reports (Wendorf and Malville, 2001) are identified in recent georectified 60cm panchromatic satellite imagery of Nabta Playa, Southern Egypt. The satellite images allow refinement, often significant of the reported locations of the megaliths (Malville et al 1998, and Wendorf and Malville 2001). The report that a primary megalithic alignment was constructed to point to the bright star Sirius, circa 4820BC, is reconsidered in light of the satellite data, new field, data, radiocarbon, lithostratigraphic and geochronological data, and the playa sedimentation history. Other possible archaeoastronomical interpretations are considered for that alignment, including the three star asterism (of Alnitak, Alniham and Mintaka) circa 6270BC that is also implicated in the small Nebta Playa "calendar circle". Signatures of other possible features apparent in the satellite imagery and a recent field study are also considered. Only a small number of the subsurface bedrock sculptures have been excavated. We recommend the use of ground penetrating imaging methods to illuminate the known but not yet excavated subsurface features. The problem of determining the astronomical intent of the builders of the megalithic structures is approached by considering the complex of features as a whole.

  18. Assigning sex and reproductive stage to adult Lake Sturgeon using ultrasonography and common morphological measurements

    Science.gov (United States)

    Chiotti, Justin A.; Boase, James C.; Hondorp, Darryl W.; Briggs, Andrew S.

    2016-01-01

    Sex determination of fish species is difficult to assess when sexual dimorphism and gametes are not apparent. For threatened and endangered fish species, noninvasive techniques are needed when determining sex to minimize stress and the potential for mortality. We evaluated the use of a portable ultrasound unit to determine sex of Lake Sturgeon Acipenser fulvescens in the field. Ultrasound images were collected from 9 yellow-egg (F2, F3), 32 black-egg (F4, F5), and 107 fully developed male (M2) Lake Sturgeon. Two readers accurately assigned sex to 88–96% of fish, but accuracy varied in relation to maturity stage. Black-egg females and fully developed males were correctly identified for 89–100% of the fish sampled, while these two readers identified yellow-egg females only 33% and 67% of the time. Time spent collecting images ranged between 2 and 3 min once the user was comfortable with operating procedures. Discriminant analysis revealed the total length : girth ratio was a strong predictor of sex and maturity, correctly classifying 81% of black-egg females and 97% of the fully developed males. However, yellow-egg females were incorrectly classified on all occasions. This study shows the utility of using ultrasonography and a total length : girth ratio for sex determination of Lake Sturgeon in later reproductive stages around the spawning season.

  19. Non-Pollen Palynomorphs Characteristic for the Dystrophic Stage of Humic Lakes in the Wigry National Park, Ne Poland

    Directory of Open Access Journals (Sweden)

    Fiłoc Magdalena

    2015-06-01

    Full Text Available The numerous dystrophic (humic lakes are a very important feature of Wigry National Park, NE Poland. As the most recent palaeoecological data indicate, at the beginning of its development (in the Late Glacial and Early and Middle Holocene these water bodies functioned as harmonious lakes, and their transformation into dystrophic lakes and the stabilization of the trophic state took place at the beginning of the Subboreal. Palynological analysis of sediments from two such lakes (Lake Ślepe and Lake Suchar II, with special emphasis on non-pollen palynomorphs (NPPs, was aimed at a detailed biological characterization of dystrophic lakes during their long-lasting existence. The obtained results allowed for the designation of organisms characteristic for dystrophic lakes, of which representatives appeared with the decreasing pH of the water and the formation of Sphagnum peat around lakes. These organisms were divided into four groups: algae, fungi, testate amoebas, and animals. Their representatives appear invarious developmental stages of dystrophic lakes.

  20. Turismo y bibliotecas: las playas de Benidorm

    Directory of Open Access Journals (Sweden)

    Couto de Granja, Antonio

    2001-03-01

    Full Text Available Se parte del objetivo principal de modernizar el concepto de lectura y biblioteca, acercando el libro a los usuarios independientemente donde se encuentren. Benidorm es un municipio conocido mundialmente por su clima y sus playas. ¿Por qué no ofrecer además cultura? Del intento de aunar ambos conceptos (lectura y ocio en un espacio común, surge la idea de las biblioplayas, donde podemos leer libros en diferentes idiomas o periódicos de nueve países europeos. En definitiva: utilizar la lectura como un medio de ocio y diversión, y la playa … como un espacio cultural.

  1. The utilization of ERTS-1-generated photographs in the evaluation of the Iranian playas as potential locations for economic and engineering development. [hydrology and morphology of playa soils

    Science.gov (United States)

    Krinsley, D. B. (Principal Investigator)

    1973-01-01

    The author has identified the following significant results. Hydrologic inventories, throughout the year, were made in interior basins that have not been measured previously because of their inaccessibility. Interior basins during the last ERTS-1 year (August 1972 to August 1973) had driest ground conditions in late September 1972 and had wettest ground conditions from March through May 1973, depending upon location. Bearing strengths of playa soils can be inferred from the changing hydrologic conditions through the seasons as recorded by ERTS-1, with prior ground control. Slight differences in salt-crust morphology and in moisture contest of playa soils can be greatly enhanced by rationing and stretching techniques. Differences in water area and silt content can be enhanced by using a three-stage photographic masking technique employing bands 4, 5, and 7.

  2. Filed-Analog Study: Efficiency of microbial fossilization in sulfate-rich playas

    Science.gov (United States)

    Glamoclija, M.; Zeidan, M.; Potochniak, S.

    2015-12-01

    The samples with the highest priority for sample return will be samples that contain potential life signatures. Sulfate-rich salts have been identified as important component of Mars sedimentary deposits, illustrating the importance of near-surface hydrological processes during the planet's history. The presence of Noachian/early Hesperian sulfate-rich deposits have been identified by the MER's Opportunity at Meridiani Planum and by MRO mission in sedimentary sequences within Gale crater, the Mars Science Laboratory landing site. White Sands National Monument, which we are using as a terrestrial analog in our study, holds active playas that may contain different sizes of water bodies during the year. Alkali Flat contains also preserved deposits of Pleistocene Lake Otero. The presence of a range of modern playas and equivalent Pleistocene deposits allows for an excellent comparison of these different extreme transitional habitats and potential of preservation of organics in an evaporitic playa setting. We have performed shallow drilling (1m) of the Lake Lucero deposits and of Lake Otero evaporitic sequence. The XRD analysis revealed that samples are mainly composed of gypsum and minor mineral phases as brushite, halite and quartz. SEM/EDS revealed the presence of amorphous phases such as halite, glauberite, magnesium chlorite salt, and diatom shells and biofilm. Biofilm is found in near surface samples, which may be attributed to microbial adaptation to desert environment and considered as one of the characteristics of modern and not fossil microbial communities. The compositional difference of salt precipitates associated with potentially geologically old biofilm and the modern counterpart are still ongoing and our findings will be presented at the conference. Further, comparison of environmental physicochemical conditions and molecular biology will be used to determine the characteristics of modern microbial habitats/deposits and to attempt to distinguish them

  3. Statistical changes in lakes in urbanizing watersheds and lake return frequencies adjusted for trend and initial stage utilizing generalized extreme value theory

    Science.gov (United States)

    Paynter, Shayne

    Many water resources throughout the world are demonstrating changes in historic water levels. Potential reasons for these changes include climate shifts, anthropogenic alterations or basin urbanization. The focus of this research was threefold: (1) to determine the extent of spatio-temporal changes in regional precipitation patterns, (2) to determine the statistical changes that occur in lakes with urbanizing watersheds, and (3) to develop accurate prediction of trends and lake level return frequencies. To investigate rainfall patterns regionally, appropriate distributions, either gamma or generalized extreme value (GEV), were fitted to variables at a number of rainfall gages utilizing maximum likelihood estimation. The spatial distribution of rainfall variables was found to be quite homogenous within the region in terms of an average annual expectation. Furthermore, the temporal distribution of rainfall variables was found to be stationary with only one gage evidencing a significant trend. In order to study statistical changes of lake water surface levels in urbanizing watersheds, serial changes in time series parameters, autocorrelation and variance were evaluated and a regression model to estimate weekly lake level fluctuations was developed. The following general conclusions about lakes in urbanizing watersheds were reached: (1) The statistical structure of lake level time series is systematically altered and is related to the extent of urbanization, (2) in the absence of other forcing mechanisms, autocorrelation and baseflow appear to decrease, and (3) the presence of wetlands adjacent to lakes can offset the reduction in baseflow. In regards to the third objective, the direction and magnitude of trends in flood and drought stages were estimated and both long-term and short-term flood and drought stage return frequencies were predicted utilizing the generalized extreme value (GEV) distribution with time and starting stage covariates. All of the lakes

  4. Inorganic data from El'gygytgyn Lake sediments: stages 6–11

    Directory of Open Access Journals (Sweden)

    V. Wennrich

    2013-01-01

    Full Text Available Geochemical study was performed on sediment of deep drilling core from El'gygytgyn Lake, located in central Chukotka, northeastern Russia (67°30' N; 172°05' E. Major and rare elements were determined by X-ray fluorescence spectroscopy (XRF on 600 samples covering the timeframe between ca. 450 and 125 ka corresponding to Marine Isotope Stages (MIS 11 to 6. Inorganic geochemistry data indicates significant variations in the elemental compositions corresponding to the glacials and interglacials periods. Interglacial sediments are characterized by high contents of SiO2, Na2O, CaO, K2O, Sr and are depleted in Al2O3, Fe2O3, TiO2, MgO. Extreme enrichments in SiO2 during MIS 11.3 and 9.3 are caused by an enhanced flux of biogenic silica (BSi. Geochemical structure of stage 11 shows very similar peculiarities to features of stage 11 from records of Lake Baikal/SE Siberia and Antarctic ice cores. High contents of TiO2, Fe2O3, MgO, Al2O3, LOI, Ni, Cr and Zr are typical for sediments of glacial stages, among those MIS 7.4 and 6.6 are the most marked. Peaks in the Fe2O3 content and coinciding low Fe2O3/MnO ratios during glacials indicate reducing condition in the sediments. This is also supported by enrichments in P2O5 and MnO, indicating an increased abundance of authigenic fine grained vivianite. Some elemental ratios indicate an enhanced alteration of glacial sediments accompanied by a loss of mobile elements, like Na, Ca, K and Sr. The higher alteration of sediments can presumably be traced back to changes in the sedimentation regime and diagenetic processes, and thus, reflects environmental changes.

  5. Inhibition of the growth of cyanobacteria during the recruitment stage in Lake Taihu.

    Science.gov (United States)

    Lu, Yaping; Wang, Jin; Zhang, Xiaoqian; Kong, Fanxiang

    2016-03-01

    Microcystis is the dominant algal bloom genus in Lake Taihu. Thus, controlling the recruitment and growth of Microcystis is the most crucial aspect of solving the problem of algal blooms. Different concentrations (0.025, 0.05, and 0.1 g L(-1)) of tea extract were used to treat barrels of lake water at the recruitment stage of cyanobacteria. There was an inhibitory effect on algal growth in all treatment groups. The inhibitory effect on cyanobacteria was stronger than on other algae. The metabolic activity of cells in the treatment groups was significantly enhanced compared to the control, as an adaptation to the stress caused by tea polyphenols. The photosynthetic activity diminished in the treatment groups and was barely detected in the 0.05 and 0.1 g L(-1) treatments. The levels of reactive oxygen species increased substantially in treated cells with the algal cells experiencing oxidative damage. The effect of tea on zooplankton was also studied. The number of Bosmina fatalis individuals did not change significantly in the 0.025 and 0.05 g L(-1) treatments. These results suggested that the application of tea extracts, during the recruitment stage of blue-green algae, suppressed the recruitment and growth of cyanobacteria, thus offering the potential to prevent cyanobacterial blooms.

  6. Opposing environmental gradients govern vegetation zonation in an intermountain playa

    Science.gov (United States)

    Sanderson, J.S.; Kotliar, N.B.; Steingraeber, D.A.

    2008-01-01

    Vegetation zonation was investigated at an intermountain playa wetland (Mishak Lakes) in the San Luis Valley (SLV) of southern Colorado. Plant composition and abiotic conditions were quantified in six vegetation zones. Reciprocal transplants were performed to test the importance of abiotic factors in governing zonation. Abiotic conditions differed among several vegetation zones. Prolonged inundation led to anaerobic soils in the Eleocharis palustris and the submerged aquatics zones, on the low end of the site's 1.25 m elevation gradient. On the high end of the gradient, soil salinity and sodicity (a measure of exchangeable sodium) were high in the Distichlis spicata zone (electrical conductivity, EC = 5.3 dS/m, sodium absorption ratio, SAR = 44.0) and extreme in the Sarcobatus vermiculatus zone (EC = 21 dS/m, SAR = 274). Transplanted species produced maximum biomass in the zone where they originated, not in any other higher or lower vegetation zone. The greatest overall transplant effect occurred for E. palustris, which experienced a ??? 77% decline in productivity when transplanted to other zones. This study provides evidence that physical factors are a major determinant of vegetation zone composition and distribution across the entire elevation gradient at Mishak Lakes. Patterns at Mishak Lakes arise from counter-directional stress gradients: a gradient from anaerobic to well-oxygenated from basin bottom to upland and a gradient from extremely high salinity to low salinity in the opposing direction. Because abiotic conditions dominate vegetation zonation, restoration of the altered hydrologic regime of this wetland to a natural hydrologic regime may be sufficient to re-establish many of the natural biodiversity functions provided by these wetlands. ?? 2008 The Society of Wetland Scientists.

  7. Study on the distributions of Cd, Co, Sr, Zn, Ag, Cu, Pb, Mn and Ni in the eolian sands of the Gavkuni playa (southeast of Isfahan

    Directory of Open Access Journals (Sweden)

    Hamidreza Pakzad

    2014-11-01

    Full Text Available Introduction Heavy metals are continually introduced into hydrosphere, atmosphere and biosphere. These potentially toxic elements can concentrate in sediments in aqueous ecosystems and they can act as pollution sources in particular conditions. Heavy metals mainly concentrate in fine sand particles because of more concentration of heavy minerals in this grain size. The Gavkhuni playa lake with an approximate area of 550 km2 is located at southeast of Isfahan, Iran. The Zayandehrud permanent river and several seasonal rivers flow into this playa. During quaternary, massive volume of sediments in sand and gravel sizes were carried into this area and deposited. These sediments are mainly deposited in the delta of Zayandehrud river (northwest of Gavkhuni playa and northwest of the sand dunes in margin of the Zayandehrud river particularly from Varzaneh to the playa. The megafans surrounding the playa can be partly origin of these sediments. The Gavkhuni playa lake is composed of three major flats namely sand, mud and salt flats. The salt flat forms the major part of the playa. Igneous, metamorphic and sedimentary (mainly carbonates rocks outcrop in the drainage basin of the Gavkhuni playa lake. Schist, gneiss, limestone, shale and andesite are the dominant lithology in this basin. The main objective of this research is to determine the concentrations of Cd, Co, Sr, Zn, Ag, Cu, Pb, Mn and Ni in the eolian sand deposits, the factors influencing the distributions of these elements and also relationship between the heavy metals and the minerals (particularly heavy minerals containing these elements. Material & Methods The eolian sands (sand dunes and sand flats of the Gavkhuni playa were sampled in 15 sampling points from north to south of the playa. Grain size distribution of the sediments were determined through dry sieving method. Heavy minerals were separated and studied through microscopy of the prepared thin and polish sections. The concentration

  8. Paleomagnetic Excursions Recorded in the Yanchi Playa in Middle Hexi Corridor,NW China Since the Last Interglacial

    Institute of Scientific and Technical Information of China (English)

    YANG Taibao; YU Yongtao; LI Jijun; AN Congrong; LIU Jinfeng; ZHANG Junyan

    2004-01-01

    Paleomagnetic determinations on lithological profiles of two paralleled long drilling cores covering the past 130 kyr B.P., GT40 and GT60,from the Yanchi Playa in the arid Northwestern China,indicate that a series of pronounced paleomagnetic excursions have been documented. By correlating our results with published regional and worldwide reports,4 excursion events out of 10 apparent reversal signals (labeled from GT-1 to GT-10) were identified asexcursion events coeval with the Mono Lake Event (28.4 kyr~25.8 kyr), Laschamp Event (43.3 kyr~40.5kyr), Gaotai Event (8a.8 kyr~72.4 kyr) and the Blake Event (127.4 kyr~113.3 kyr), respectively. GT-9correlates with the above-mentioned Gaotai Event,GT-7 and GT-6 correspond to two stages of theLaschamp Event and GT-5 to the Mono Lake Event. It is noteworthy that the so-called Gaotai Event has not been reported as a pronounced paleomagnetic excursion in the Northwestern China. Every magnetic excursion event corresponds to paleointensity minima,anteceding those established abrupt paleoclimatic change events, such as the Younger Drays and the Heinrich Events(H1-H6). Here, we tentatively propose that these geomagnetic excursions/reversals can be viewed as precursors to climate abruptness.During the transitional stages when the earth's magnetic field shifted between a temporal normal and a negative period, the earth's magnetic paleointensity fell correspondingly to a pair of minima. Although more precise chronology and more convincing rock magnetic parameter determinations are essentially required for further interpretation of their intricate coupling mechanism, these results may have revealed, to some extent, that the earth's incessantly changing magnetic field exerts an strong influence on the onset of saw-tooth shaped abrupt climate oscillations through certain feedback chains in arid Central Asia or even North Hemispheric high latitude regions.

  9. New insights on the late-stage history of glacial Lake Ojibway: implications for meltwater discharges of the last deglaciation

    Science.gov (United States)

    Roy, Martin; Veillette, Jean J.; Godbout, Pierre-Marc

    2016-04-01

    The decay of the Laurentide ice sheet is believed to be responsible for abrupt climate variations during the last deglaciation and early Holocene, notably through massive discharges of meltwater that had accumulated in large ice-dammed lakes such as Lake Agassiz and Lake Ojibway. Indeed, high-resolution North Atlantic marine records indicate that the ocean's circulation was affected by several outbursts of meltwater during the late deglacial interval. Yet, field evidence and geological data supporting multi-step drawdowns of Lake Agassiz-Ojibway are relatively limited, underlying important uncertainties in the late-stage history of these glacial lakes. Furthermore, physical evidence for the drainage of glacial lakes remains relatively rare in depositional records, giving rise to much debate on the location of outlets and discharge pathways, as well as on the climate impact of the attendant meltwater forcing. Recent investigations of geomorphological and sedimentary records in northern Ontario and Quebec (Canada) have revealed new insights on the late-stage evolution of Lake Ojibway. The number of Ojibway lake phases have so far remained poorly documented mainly because of the dominance of fine-grained glaciolacustrine sediments in the lake basin that prevented the formation of extensive sandy/bouldery strandlines. We thus developed an alternative approach based on the study of a complex sequence of relict terraces carved in the Ojibway clay plain. The elevation measurement of 154 raised wave-cut scarps provided evidence for four distinct shorelines, three of which projecting well below the main outlet that controlled the elevation of the lake during the deglaciation. The elevation, uplift gradients, and areal extent of these shorelines indicate that these low-elevation lake levels formed during the late stages of the deglaciation, following abrupt drawdowns of the lake's surface. Insights on the origin of these late-stage phases are provided from sediment sequences

  10. sol y playa: el caso de Tenerife

    Directory of Open Access Journals (Sweden)

    Ricardo J. Díaz Armas

    2008-01-01

    Full Text Available El turismo del vino tiene una concepción distinta en un destino masivo de sol y playa. En este caso el enoturismo convive con ese modelo turístico y es un producto complementario que favorece la diversificación en la oferta actual. El turismo del vino puede complementar la ya existente oferta turística, con lo que las regiones, turísticas y a la vez viníferas, podrían apoyarse en las experiencias y conocimiento del vino por parte del visitante y utilizarlas como hecho diferencial competitivo frente a otros destinos de sol y playa que no poseen esta particularidad. Con ello además se favorecerá el lanzamiento del producto turístico del vino, pues la demanda latente ya esta en las zonas turísticas que rodean el área vinícola. En este sentido, una vez que se descubren las motivaciones para acudir al destino Tenerife, se localiza un mercado sensible a la ruta del vino Tacoronte-Acentejo en el asentamiento turístico del Puerto de la Cruz (una de las principales zonas turísticas de Tenerife. Así, tras conocer los beneficios buscados por el visitante del Puerto de la Cruz, se ha contrastado la existencia de dos segmentos latentes que pueden ser atraídos hacia la oferta actual de la ruta del vino en Tacoronte-Acentejo, al verificar que persiguen, además del clima y el sol y playa (principales motivaciones para viajar al destino Tenerife, otros beneficios que son susceptibles de ser ofertados por la ruta del vino.

  11. Lake

    Science.gov (United States)

    Wien, Carol Anne

    2008-01-01

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

  12. Dormant stages of crustaceans as a mechanism of propagation in the extreme and unpredictable environment in the Crimean hypersaline lakes

    Science.gov (United States)

    Shadrin, Nickolai V.; Anufriieva, Elena V.; Amat, Francisco; Eremin, Oleg Yu.

    2015-11-01

    A pool of dormant stages of planktonic organisms in saline lakes is a substantial component in the plankton communities; we need to take it into account to understand plankton dynamics. Hypersaline water bodies in Crimea, the largest peninsula in the Black Sea, constitute a very characteristic and peculiar habitat type in the region. We examined the presence of crustacean resting stages in sediments of dried up sites of the Crimean hypersaline lakes. Sediment samples were taken in 9 different lakes. Experiments performed on the hatching of these resting stages showed the presence of Moina salina (Cladocera), parthenogenetic Artemia and Artemia urmiana (Anostraca), Eucypris mareotica ( inflata) (Ostracoda), and Cletocamptus retrogressus (Harpacticoida). Comparing the experimental results obtained with clean dried brine shrimp cysts and those kept in sediment samples, it was noted that clean cysts hatched much faster than those from sediments did. Some components in bottom sediments slow down and desynchronize hatching from resting eggs in different groups of crustaceans. The sediments of different lakes inhibited the nauplii output from Artemia and ostracod resting eggs to different degrees. More data are needed before we can discuss the reasons of this inhibition. The nonsynchronous output of active stages from the bottom resting ones may be an adaptation that allows crustacean species to exist in extreme and unpredictably changing environments, avoiding the risk that all may emerge at once under unsuitable conditions.

  13. IMPLICATION OF LAKE WATER RESIDENCE TIME ON THE CLASSIFICATION OF NORWEGIAN SURFACE WATER SITES INTO PROGRESSIVE STAGES OF NITROGEN SATURATION

    Science.gov (United States)

    Seasonal behaviour of NO3- in surface water is often used as an indicator on a catchment's ability to retain N from atmospheric deposition. In this paper, we classify 12 pristine sites (five streams and seven lakes) in southernmost Norway according to the N saturation stage conce...

  14. Water quality variation of mining-subsidence lake during the initial stage: cases study of Zhangji and Guqiao Mines

    Institute of Scientific and Technical Information of China (English)

    FAN Tina-yu; YAN Jia-ping; WANG Shun; ZHANG Bing; RUAN Shu-xian; ZHANG Mei-li; LI Shou-qin; CHEN Yong-chun; LIU Jin

    2012-01-01

    Four quarters' water collecting and monitoring samples were done in the mining subsidence lakes of different water storing periods (2 to 7 years),considering the water storing time and pollution sources state of the subsidence lakes.The following indexes were discussed such as organic indexes (TOC,CODMn,BOD,COD),nutrient salts (TN,NH4+,NO3-,NO2-,Kjeldahl Nitrogen,TP,PO43-),etc.It is shown that water quality of the mining subsidence lake during the initial stage (2 years to 7 years) can stay relatively stable with a fluctuation during different quarters in a year,which can reach class Ⅲ or Ⅳ of the Surface Water Environmental Quality Standard.

  15. Las playas de Quintana Roo: sus riesgos y vulnerabilidad.

    Directory of Open Access Journals (Sweden)

    Daniel Torruco Gómez

    2013-01-01

    Full Text Available Las playas son sistemas donde se ejercen presiones antrópicas y ambientales, en este estudio se analizaron sus condiciones bioeconómicas con la finalidad de obtener un modelo que permita determinar el grado de vulnerabilidad y la matriz de riesgo en las playas del Estado de Quintana Roo para un mejor uso sustentable. Se formularon matrices con registros biológicos y socioeconómicos obtenidos entre el 2009 y 2010 en temporadas de alto registro turístico, obteniendo 17 variables en 20 playas analizadas. La evaluación se efectuó con el modelo semiparamétrico del tipo KSIM con dos escenarios: uno sin control/restricción en el desarrollo costero y otro con las mismas características pero con decremento en demanda turística por baja calidad ambiental. Los resultados mostraron un marcado descenso en playas arenosas y costas rocosas. En el modelo se hace referencia a la importancia de los procesos de las playas y su interrelación con los factores biológicos, sociales y económicos más importantes, proporcionando una visión integral de todas las variables. Se recomienda incrementar el modelo dándole mayor envergadura, integrando a las instituciones que influyen en el control de las acciones en estas playas, lo que dará un mejor referente y monitoreo a corto, mediano y largo plazo.

  16. Evidence of the Pan-Lake Stage in the Period of 40- 28 ka B.P. on the Qinghai-Tibet Plateau

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The Qinghai-Tibet plateau is one of major saline lake regions in China, where saline lakes are widespread and constitute an important object of researches on the palaeoclimatic change in the region. On the basis of comprehensive investigations of the evolution of the lake's surface and sediments on the plateau, the authors have further demonstrated the existence of a pan-lake stage (river and lake flooding stage) on the Qinghai-Tibet plateau during the period of about 40+- 28 ka B.P. and analyzed the palaeoclimatic characteristics of the pan-lake period and relationships between the ancient monsoons and the uplift of the plateau since the beginning of the Quaternary.

  17. Dieta de la lagartija de las playas Microlophus peruvianus (Reptilia: Tropiduridae en la playa Santo Domingo, Ica, Perú

    Directory of Open Access Journals (Sweden)

    Eliana Quispitúpac

    2008-12-01

    Full Text Available La lagartija de las playas Microlophus peruvianus es uno de los saurios más conspicuos del Desierto Costero peruano, sin embargo, existe muy poca información sobre su dieta. Se reporta información de la dieta de M. peruvianus en la playa Santo Domingo, Ica, que evidencia importantes diferencias entre los principales item alimentarios de juveniles y adultos, que podrían estar reduciendo la competencia intraespecífica.

  18. Early life stages of fish and the relationships with zooplankton in a tropical Brazilian reservoir: Lake Monte Alegre.

    Science.gov (United States)

    Meschiatti, A J; Arcifa, M S

    2002-02-01

    For evaluating the trophic relationship between early life stages of fish and zooplankton in Lake Monte Alegre, fish distribution and feeding habits have been studied in areas with and without macrophytes. In the first of these areas, 356 specimens belonging to 8 species, mostly juveniles, were caught by a sieve. Another 35 specimens, belonging to 4 species, were caught by gill nets and seine in areas lacking macrophytes. Their diets were composed of aquatic insects, microcrustaceans, rotifers, detritus, and other aquatic invertebrates. Microcrustacean prey were mainly littoral or benthic dwellers, found in the highest proportion in specimens of 7-20 mm SL. Most fish species have parental care, which could explain the absence of planktonic larvae. Early life stages of fish do not exert a predation pressure on the lake zooplankton.

  19. Early life stages of fish and the relationships with zooplankton in a tropical Brazilian reservoir: Lake Monte Alegre

    Directory of Open Access Journals (Sweden)

    MESCHIATTI A. J.

    2002-01-01

    Full Text Available For evaluating the trophic relationship between early life stages of fish and zooplankton in Lake Monte Alegre, fish distribution and feeding habits have been studied in areas with and without macrophytes. In the first of these areas, 356 specimens belonging to 8 species, mostly juveniles, were caught by a sieve. Another 35 specimens, belonging to 4 species, were caught by gill nets and seine in areas lacking macrophytes. Their diets were composed of aquatic insects, microcrustaceans, rotifers, detritus, and other aquatic invertebrates. Microcrustacean prey were mainly littoral or benthic dwellers, found in the highest proportion in specimens of 7-20 mm SL. Most fish species have parental care, which could explain the absence of planktonic larvae. Early life stages of fish do not exert a predation pressure on the lake zooplankton.

  20. Dust Emissions from Undisturbed and Disturbed, Crusted Playa Surfaces: Cattle Trampling Effect

    Science.gov (United States)

    Zobeck, T. M.; Baddock, M. C.; van Pelt, R.; Fredrickson, E. L.

    2009-12-01

    Dry playa lake beds can be a significant source of fine dust emissions during high wind events in arid and semiarid landscapes. The physical and chemical properties of the playa surface control the amount and properties of the dust emitted. In this study, we use a field wind tunnel to quantify the dust emissions from a bare, fine-textured playa surface located in the Chihuahua Desert at the Jornada Experimental Range, near Las Cruces, New Mexico, USA. We tested natural, undisturbed crusted surfaces and surfaces that had been subjected to two levels of domestic animal disturbance. The animal disturbance was provided by trampling produced from one and ten passes along the length of the wind tunnel by a 630 kg Angus-Hereford cross cow. The trampling broke the durable crust and created loose erodible material. Each treatment (natural crust, one pass, and ten passes) was replicated three times. A push-type wind tunnel with a 6 m long, 0.5 m wide, and 1 m high test section was used to generate dust emissions under controlled conditions. Clean medium sand was dropped onto the playa surface to act as an abrader material. The tunnel wind speed was equivalent to 15 m/s at a height of 2 m over a smooth soil surface. The tunnel was initially run for ten minutes, with no abrader added. A second 30 minute run was subsequently sampled as abrader was added to the wind stream. Dust and saltating material were collected using an isokinetic slot sampler at the end of the tunnel. Total airborne dust was collected on two 25 cm x 20 cm glass fiber filters (GFF) and measured using a GRIMM particle monitor every 6 sec throughout each test run. Disturbance by trampling generated increased saltating material and airborne dust. The amount of saltating material measured during the initial (no abrader added) run was approximately 70% greater and 5.8 times the amount of saltating material measured on the one pass and ten pass plots, respectively, compared with that observed on the undisturbed

  1. A Citizen Science Program for Monitoring Lake Stages in Northern Wisconsin

    Science.gov (United States)

    Kretschmann, A.; Drum, A.; Rubsam, J.; Watras, C. J.; Cellar-Rossler, A.

    2011-12-01

    Historical data indicate that surface water levels in northern Wisconsin are fluctuating more now than they did in the recent past. In the northern highland lake district of Vilas County, Wisconsin, concern about record low lake levels in 2008 spurred local citizens and lake associations to form a lake level monitoring network comprising citizen scientists. The network is administered by the North Lakeland Discovery Center (NLDC, a local NGO) and is supported by a grant from the Citizen Science Monitoring Program of the Wisconsin Department of Natural Resources (WDNR). With technical guidance from limnologists at neighboring UW-Madison Trout Lake Research Station, citizen scientists have installed geographic benchmarks and staff gauges on 26 area lakes. The project engages citizen and student science participants including homeowners, non-profit organization member-participants, and local schools. Each spring, staff gauges are installed and referenced to fixed benchmarks after ice off by NLDC and dedicated volunteers. Volunteers read and record staff gauges on a weekly basis during the ice-free season; and maintain log books recording lake levels to the nearest 0.5 cm. At the end of the season, before ice on, gauges are removed and log books are collected by the NLDC coordinator. Data is compiled and submitted to a database management system, coordinated within the Wisconsin Surface Water Integrated Monitoring System (SWIMS), a statewide information system managed by the WDNR in Madison. Furthermore, NLDC is collaborating with the SWIMS database manager to develop data entry screens based on records collected by citizen scientists. This program is the first of its kind in Wisconsin to utilize citizen scientists to collect lake level data. The retention rate for volunteers has been 100% over the three years since inception, and the program has expanded from four lakes in 2008 to twenty-six lakes in 2011. NLDC stresses the importance of long-term monitoring and the

  2. Casa para la playa, New Jersey

    Directory of Open Access Journals (Sweden)

    Breuer, Marcel

    1964-03-01

    Full Text Available The McMullan house, built on the beach, has been designed to be inhabited all the year round. Basically this building is a rectangular block, lifted above the dunes on a framework of timber columns and beams. The ground floor contains the entrance hall, the guest room or servant's quarters, including a bath room, and a shower room which can be reached separately from the beach. The second floor is taken up with the main living quarters, and the second floor contains the bedrooms. The northern and southern sides have few windows, whilst the eastern and western sides have balconies protected with sliding and Venetian blinds, which in addition to supplying an effective protection against the sun, give the house a pleasant sense of secluded intimacy. The blinds are made of wood, and are painted dark brown. Doors and windows are also made of wood, but painted white. This beautiful house on the New Jersey coast exhibits in a marked degree the sculptural quality of architecture, a three dimensional plasticity, which is often neglected in many buildings of the more simple kind. Marcel Breuer has succeeded in making each of the facades of this elementary boxlike design have an interest of its own, by playing with their colour, light and shade effects, texture and combination of materials.La casa McMullan, construida en la playa, está proyectada para ser habitada durante todo el año. En esencia es un bloque paralelepipédico, elevado sobre las dunas y sustentado por un sistema de columnas y vigas de madera vistas, tanto en el interior como en el exterior. Su planta baja alberga: la entrada principal, habitación de huéspedes o de servicio con baño y una ducha con acceso desde la playa. El primer piso agrupa las dependencias nobles. Y el segundo, la zona de dormitorios. Las fachadas norte y sur presentan pocos huecos al exterior; y las este y oeste disponen de galerías con persianas correderas y celosías, que, además de proporcionar intimidad a la

  3. Relative Influence of Prior Life Stages and Habitat Variables on Dragonfly (Odonata: Gomphidae Densities among Lake Sites

    Directory of Open Access Journals (Sweden)

    Alysa Remsburg

    2011-04-01

    Full Text Available Many aquatic species have discrete life stages, making it important to understand relative influences of the different habitats occupied within those populations. Although population demographics in one stage can carry over to spatially separated life stages, most studies of habitat associations have been restricted to a single life stage. Among Gomphidae dragonflies (Odonata: Anisoptera, recruitment via adult oviposition establishes initial population sizes of the aquatic larvae. However, spatial variability in larval survivorship could obscure the relationship between adult and larval densities. This study uses surveys conducted during 2005 and 2006 of Gomphidae larval, emergence, and adult stages from 22 lake sites in northern Wisconsin, USA, to investigate (1 whether the Gomphidae density of each life stage correlated spatially with that of the preceding life stage and (2 what habitat factors help explain variation in densities at each life stage. Results indicated that adult densities from the previous season helped predict densities of early-instar larvae. This finding suggests that oviposition site selection controlled the local larval distribution more than larval survivorship or movement. Late-instar larval densities helped predict densities of emerging Gomphidae later the same season, suggesting that variation in survivorship of final-instar larvae among sites is small relative to the variation in larval recruitment. This study demonstrates that locations with higher densities of odonates in the water also have higher densities of odonates on land. In addition to the densities of Gomphidae in previous life stages, water clarity helped predict larval densities, and riparian wetland vegetation helped predict emergent dragonfly densities.

  4. Glacially derived material in an Inner Mongolian desert lake during Marine Isotope Stage 2

    Digital Repository Service at National Institute of Oceanography (India)

    Selvaraj, K.; Chen, C-T.A.; PrakashBabu, C.; Lou, J-Y.; Liu, C-L.; Hsu, K.J.

    (Wuliangsuhai Lake) that show two distinct glacially derived sedimentation events at approx. 26.2-21.8 and approx. 17.3-11.5k cal a BP are presented. Fine sediments from the Last Glacial Maximum separate these glacially derived coarse sediments. Within...

  5. Numerical investigation of coupled density-driven flow and hydrogeochemical processes below playas

    Science.gov (United States)

    Hamann, Enrico; Post, Vincent; Kohfahl, Claus; Prommer, Henning; Simmons, Craig T.

    2015-11-01

    Numerical modeling approaches with varying complexity were explored to investigate coupled groundwater flow and geochemical processes in saline basins. Long-term model simulations of a playa system gain insights into the complex feedback mechanisms between density-driven flow and the spatiotemporal patterns of precipitating evaporites and evolving brines. Using a reactive multicomponent transport model approach, the simulations reproduced, for the first time in a numerical study, the evaporite precipitation sequences frequently observed in saline basins ("bull's eyes"). Playa-specific flow, evapoconcentration, and chemical divides were found to be the primary controls for the location of evaporites formed, and the resulting brine chemistry. Comparative simulations with the computationally far less demanding surrogate single-species transport models showed that these were still able to replicate the major flow patterns obtained by the more complex reactive transport simulations. However, the simulated degree of salinization was clearly lower than in reactive multicomponent transport simulations. For example, in the late stages of the simulations, when the brine becomes halite-saturated, the nonreactive simulation overestimated the solute mass by almost 20%. The simulations highlight the importance of the consideration of reactive transport processes for understanding and quantifying geochemical patterns, concentrations of individual dissolved solutes, and evaporite evolution.

  6. Oxygen isotope composition of water and snow-ice cover of isolated lakes at various stages of separation from the White Sea

    Science.gov (United States)

    Lisitzin, A. P.; Vasil'chuk, Yu. K.; Shevchenko, V. P.; Budantseva, N. A.; Krasnova, E. D.; Pantyulin, A. N.; Filippov, A. S.; Chizhova, Ju. N.

    2013-04-01

    This study aimed to analyze the oxygen isotope composition of water, ice, and snow in water bodies isolated from the White Sea and to identify the structural peculiarities of these pools during the winter period. The studies were performed during early spring in Kandalaksha Bay of the White Sea, in Velikaya Salma Strait and in Rugoserskaya Inlet. The studied water bodies differ in their degree of isolation from the sea. In particular, Ermolinskaya Inlet has normal water exchange with the sea; the Lake on Zelenyi Cape represents the first stage of isolation; i. e., it has permanent water exchange with the sea by the tide. Kislo-Sladkoe Lake receives sea water from time to time. Trekhtsvetnoe Lake is totally isolated from the sea and is a typical meromictic lake. Finally, Nizhnee Ershovskoe Lake exhibits some features of a saline water body. The oxygen isotope profile of the water column in Trekhtsvetnoe Lake allows defining three layers; this lake may be called typically meromictic. The oxygen isotope profile of the water column in Kislo-Sladkoe Lake is even from the surface to the bottom. The variability of δ18O is minor in Lake on Zelenyi Cape. A surface layer (0-1 m) exists in Nizhnee Ershovskoe Lake, and the oxygen isotope variability is well pronounced. Deeper, where the freshwater dominates, the values of ?18Îvary insignificantly disregarding the water depth and temperature. This fresh water lake is not affected by the seawater and is not stratified according to the isotope profile. It is found that applying the values of ?18Î and profiles of temperature and salinity may appear as an effective method in defining the water sources feeding the water bodies isolated from the sea environment.

  7. Land use and conservation reserve program effects on the persistence of playa wetlands in the High Plains.

    Science.gov (United States)

    Daniel, Dale W; Smith, Loren M; Haukos, David A; Johnson, Lacrecia A; McMurry, Scott T

    2014-04-15

    Watershed cultivation and subsequent soil erosion remains the greatest threat to the service provisioning of playa wetlands in the High Plains. The U.S. Department of Agriculture's (USDA) Conservation Reserve Program (CRP) plants perennial vegetation cover on cultivated lands including playa watersheds, and therefore, the program influences sediment deposition and accumulation in playas. Our objective was to measure the effects of the CRP on sediment deposition by comparing sediment depth and present/historic size characteristics in 258 playas among three High-Plains subregions (northern, central, and southern) and the three dominant watershed types: cropland, CRP, and native grassland. Sediment depth and resultant volume loss for CRP playas were 40% and 57% lower than cropland playas, but 68% and 76% greater than playas in native grassland. Playas in CRP had remaining volumes exceeding those of cropland playas. Grassland playas had nearly three times more original playa volume and 122% greater wetland area than CRP playas. Overall, playas were larger in the south than other subregions. Sediment depth was also three times greater in the south than the north, which resulted in southern playas losing twice as much total volume as northern playas. However, the larger southern playas provide more remaining volume per playa than those in other subregions. The results of this study demonstrate the importance of proper watershed management in preserving playa wetland ecosystem service provisioning in the High Plains. Furthermore, we identify regional differences in playas that may influence management decisions and provide valuable insight to conservation practitioners trying to maximize wetland services with limited resources.

  8. Biophysical controls over concentration and depth distribution of soil organic carbon and nitrogen in desert playas

    Science.gov (United States)

    McKenna, Owen P.; Sala, Osvaldo E.

    2016-12-01

    Playa wetlands are important areas of soil organic carbon and nutrient storage in drylands. We conducted this study to assess how catchment biophysical variables control soil organic carbon and nitrogen in playas and how playas function differently than upland ecosystems. We found that playa organic carbon and nitrogen corresponded primarily with catchment vegetation cover and secondarily with catchment area, slope, and soil texture. The effect of increased organic matter production associated with high catchment vegetation cover overshadowed the potential effect of reduced run-on. We also found soil carbon and nitrogen profiles to be significantly shallower in playas than uplands. This trend is correlated with evidence of sedimentation and shallow-rooted plants in playas. Upland soils had a deeper carbon and nitrogen profile, which correlated with organic matter being generated by deeply rooted vegetation. In playas, C:N ratios remained constant through depth but in uplands, C:N ratios increased through depth. We found evidence that differences in rooting depth distributions and soil texture may explain these C:N variations between uplands and playas. In uplands, clay concentration increased with depth, whereas in playas, clay concentration did not change with depth, which highlighted the important role of sedimentation in these ecosystems. Our results suggest that small changes in playa catchment vegetation cover in response to climate change or grazing intensity would greatly impact playa soil organic carbon and nitrogen stocks. This effect would be due to the playa soils dependence on allochthonous organic matter and the large upland area that drains into playas.

  9. Playa de sol: La cabaña del sur

    Directory of Open Access Journals (Sweden)

    Adel López Gómez

    1964-01-01

    Full Text Available La "Cabaña del Sur" no ha cambiado nada durante mis dos años de ausencia. Ahí está, en la playa de Bocagrande, con su alta techumbre de paja, a cuarenta o cincuenta metros del mar, con su pequeño mirador y sus ventanas abiertas sobre la inmensidad del Pacífico, al final del pequeño caserío negro.

  10. Trends in Playa Inundation and Water Storage in the Ogallala Aquifer on the Texas High Plains

    Directory of Open Access Journals (Sweden)

    Dennis Gitz

    2016-08-01

    Full Text Available The Ogallala Aquifer is an important source of irrigation water on the Texas High plains; however, significant decreases in saturated thickness threaten its future use for irrigation. A better understanding of the roles of playas, ephemeral surface ponds, in aquifer recharge is needed to establish levels of withdrawals that will meet either established desired future conditions or sustainability. In this study, data regarding playa inundation, depth to groundwater, precipitation and land cover from 2001 to 2011 were collected and analyzed to ascertain associations between these characteristics for four study areas on the Texas High plains. Each area covered 40,000–70,000 ha. Three of the study areas in Hockley, Floyd and Swisher counties were chosen because their center contained a playa instrumented to measure weather and depth of inundation. There were 20 distinct inundation events at the three instrumented playas between 2006 and 2010. For each of these inundations, water loss exceeded rates of potential evapotranspiration (ET by a factor of 1.6–15.7 times, implying that infiltration was occurring. Playa inundation in all four study areas was also assessed by analyzing images from the National Agricultural Imaginary program. Data on depth to groundwater were analyzed from 2000 to 2010 to determine annual changes of stored water. Annual changes in groundwater were weakly associated with surface area of inundated playas in late summer, but was strongly associated with annual rainfall. Rates of infiltration based on playa water loss versus potential ET, and volume of water in playas was more than sufficient to account for annual changes in groundwater. Land use adjoining the playas had less of influence on playa inundation than annual rainfall. These results strengthen the argument that water storage in playas on the Texas High Plains is an important source of water for aquifer recharge.

  11. Macropolygon morphology, development, and classification on North Panamint and Eureka playas, Death Valley National Park CA

    Science.gov (United States)

    Messina, P.; Stoffer, P.; Smith, W.C.

    2005-01-01

    Panamint and Eureka playas, both located within Death Valley National Park, exhibit a host of surficial features including fissures, pits, mounds, and plant-covered ridges, representing topographic highs and lows that vary up to 2 m of relief from the playa surface. Aerial photographs reveal that these linear strands often converge to form polygons, ranging in length from several meters to nearly a kilometer. These features stand out in generally dark contrast to the brighter intervening expanse of flat, plant-free, desiccated mud of the typical playa surface. Ground-truth mapping of playa features with differential GPS (Global Positioning System) was conducted in 1999 (North Panamint Valley) and 2002 (Eureka Valley). High-resolution digital maps reveal that both playas possess macropolygons of similar scale and geometry, and that fissures may be categorized into one of two genetic groups: (1) shore-parallel or playa-interior desiccation and shrinkage; and (2) tectonic-induced cracks. Early investigations of these features in Eureka Valley concluded that their origin may have been related to agricultural activity by paleo-Indian communities. Although human artifacts are abundant at each locale, there is no evidence to support the inference that surface features reported on Eureka Playa are anthropogenic in origin. Our assumptions into the genesis of polygons on playas is based on our fortuitous experience of witnessing a fissure in the process of formation on Panamint Playa after a flash flood (May 1999); our observations revealed a paradox that saturation of the upper playa crusts contributes to the establishment of some desiccation features. Follow-up visits to the same feature over 2 yrs' time are a foundation for insight into the evolution and possible longevity of these features. ?? 2005 Elsevier B.V. All rights reserved.

  12. A biomarker record of Lake El'gygytgyn, Far East Russian Arctic: investigating sources of organic matter and carbon cycling during marine isotope stages 1–3

    Directory of Open Access Journals (Sweden)

    A. R. Holland

    2013-01-01

    Full Text Available Arctic paleoenvironmental archives serve as sensitive recorders of past climate change. Lake El'gygytgyn (Far East Russian Arctic is a high-latitude crater impact lake that contains a continuous sediment record influenced by neither glaciation nor glacial erosion since the time of impact 3.58 Ma ago. Prior research on sediments collected from Lake El'gygytgyn suggest times of permanent ice cover and anoxia corresponding to global glacial intervals, during which the sediments are laminated and are characterized by the co-occurrence of high total organic carbon, microscopic magnetite grains that show etching and dissolution, and negative excursions in bulk sediment organic matter carbon isotope (δ13C values. Here we investigate the abundance and carbon isotopic composition of lipid biomarkers recovered from Lake El'gygytgyn sediments spanning marine isotope stages 1–3 to identify key sources of organic matter (OM to lake sediments, to establish which OM sources drive the negative δ13C excursion exhibited by bulk sediment OM, and to explore if there are molecular and isotopic signatures of anoxia in the lake during glaciation. We find that during marine isotope stages 1–3, direct evidence for water column anoxia is lacking. A ~4‰ negative excursion in bulk sediment δ13C values during the Local Last Glacial Maximum (LLGM is accompanied by more protracted, higher magnitude negative excursions in n-alkanoic acid and n-alkanol δ13C values that begin 20 kyr in advance of the LLGM. In contrast, n-alkanes and the C30 n-alkanoic acid do not exhibit a negative δ13C excursion at this time. Our results indicate that the C24, C26 and C28 n-alkanoic acids do not derive entirely from terrestrial OM sources, while the C30 n-alkanoic acid at Lake El'gygytgyn is a robust indicator of terrestrial OM contributions. Overall, our results strongly support the presence of a nutrient-poor water column, which is mostly isolated from atmospheric carbon dioxide

  13. Investigation of thiamine and PCB association with early life stage fry mortality in lake trout from northwestern Lake Michigan in 1996-1998

    Science.gov (United States)

    Honeyfield, Dale C.; Beltman, Dong; Holey, Mark; Edsall, Carol C.

    2005-01-01

    Lake trout (Salvelinus namaycush) eggs were collected from 72 females near Sturgeon Bay, WI in northwestern Lake Michigan from 1996, 1997, and 1998 to determine the relationships between egg thiamine and polychlorinated biphenyl (PCB) concentrations with egg fertilization and hatch, prevalence of abnormal fry, and fry mortality. Fry mortality consistent with early mortality syndrome (EMS) was observed in eggs from 33% of the females in 1996, 25% in 1997, and 28% in 1998. Among egg lots exhibiting EMS, fry mortality averaged 95% in 1996, 63% in 1997 and 77% in 1998 compared to 2% or less in lots that did not exhibit EMS. Expression of EMS was strongly correlated with egg thiamine concentrations; egg lots with less than approximately 1 nmol/g total thiamine consistently exhibited high rates of EMS, whereas egg batches with greater than 1.5 nmol/g showed little or no incidence of EMS among swim-up fry. Egg thiamine concentration was not related to fertilization rate, egg hatch, or the prevalence of abnormal fry. There was no relationship between egg concentrations of PCBs or tetrachlorinated dibenzo-p-dioxin (TCDD) equivalents (from PCBs, dioxins, and furans) and any of the egg or fry viability measurements, including EMS. We concluded that fry mortality observed in Lake Michigan lake trout in 1996-1998 was not caused by the toxicity of PCBs, dioxins, and furans, but is due to low egg thiamine concentrations.

  14. Pollen sequence from the Chilean Lake District during the Llanquihue glaciation in marine Oxygen Isotope Stages 4-2

    Science.gov (United States)

    Heusser, Calvin J.; Lowell, Thomas V.; Heusser, Linda E.; Moreira M., Andrés; Moreira M., Simón

    2000-02-01

    Pollen stratigraphy of a core taken from a fen at Fundo Nueva Braunau (40°17.49S, 73°04.83W), situated 2 km beyond the western border of Llanquihue-age glacial drift, spans an age range from an estimated 60 000-70 000 BP to about 14 000 14C yr BP (marine Oxygen Isotope Stages 4-2). The location at present is in the contact zone of Valdivian Evergreen Forest and Lowland Deciduous Beech Forest. Early and late in the pollen record, as indicated by assemblages of southern beech (Nothofagus dombeyi type) and grass (Gramineae), the site was located in Subantarctic Parkland. Intervening assemblages represent expansion of Valdivian-North Patagonian Evergreen Forest (> 49 355 to about 40 000 14C yr BP) and North Patagonian Evergreen Forest-Subantarctic Parkland (approximately 40 000 to 30 000 14C yr BP).Climate over the time span was under the storm regime of the Southern Westerlies and apparently uninterruptedly wet. When Subantarctic Parkland expanded, cold conditions with summer temperatures estimated at 8-9°C (7°C lower than present) resulted in episodes of glacier maxima. Climate moderated during the period of forest expansion, at which time glaciers were in a state of recession. Contrasting with the continuously wet climate of the Lake District for the period of record, climate in semi-arid-arid, subtropical Chile underwent extended intervals of precipitation. Data from both the terrestrial and marine realm implicate the Southern Westerlies as the cause of intensified storm activity at lower latitudes.

  15. Hyperspectral Mapping of Iron-bearing Minerals Associated with Dry and Ephemeral Lakes

    Science.gov (United States)

    Farrand, W. H.; Bowen, B. B.

    2014-12-01

    This research project is utilizing data from the Hyperspectral Imager for the Coastal Ocean (HICO) on the International Space Station (ISS) to examine a set of playas and ephemeral lakes in Australia and in the southwestern United States. HICO collects hyperspectral data from 0.35 to 1.08 μm thus excluding the SWIR vibrational overtone region of clays and carbonates. We are assessing the utility of HICO for detecting iron-bearing minerals and materials associated with playas and mapping their fractional abundance outside of the playa boundaries. Sites being investigated include the clastics-dominated Railroad Valley and Lunar Lake playas of Nevada, the evaporite-dominated Bonneville Salt Flats, and the acid-saline Lake Tyrrell of northwest Victoria, Australia. HICO, and supporting airborne hyperspectral datasets (AVIRIS and HyMap), are being converted from at-sensor radiance to surface reflectance using the FLAASH radiance transfer-based atmospheric correction software. Fe-bearing minerals and materials are determined through a standardized endmember detection approach using the commercial ENVI software and mapped using a variety of approaches including linear spectral mixture analysis, constrained energy minimization, and spectral feature fitting. Interpretations of remote data are guided by field-based observations and mapping. We are using the remote sensing data to assess the surface state of the playa (wet vs. dry, soft vs. hard). These factors have bearing in that dusts stripped from playa surfaces can affect nearby human communities and agricultural fields. Playas are also used for recreation and sometimes as transportation corridors and their physical state has important bearing for those functions. Assessing the types of minerals present has relevance for their impact as wind-entrained particulates that could have adverse effects on the health of humans, crops, or livestock.

  16. Variabilidad de los perfiles de playa: forma y distribución granulométrica

    OpenAIRE

    Medina, Raúl; Losada, Iñigo J.; Losada, Miguel Ángel; Vidal, César

    1995-01-01

    Las playas no son elementos estáticos de la costa sino que cambian su forma en planta y perfil a lo largo del tiempo. Estos cambios de forma, conllevan un transporte de arena que origina, a su vez, variaciones en la distribución granulométrica del material que conforma la playa. El presente trabajo se centra en la variabilidad de los perfiles de playa tanto en lo que se refiere a su forma como a su distribución granulométrica. El análisis se efectúa con base en datos medidos en varias play...

  17. Lake Roosevelt Fisheries Monitoring Progam; Thyroid-Induced Chemical Imprinting in Early Life Stages and Assessment of Smoltification in Kokanee Salmon Implications for Operating Lake Roosevelt Kokanee Salmon Hatcheries; 1993 Supplement Report.

    Energy Technology Data Exchange (ETDEWEB)

    Tilson, Mary Beth; Galloway, Heather; Scholz, Allan T. (Eastern Washington University, Upper Columbia United Tribes Fisheries Research Center, Cheney, WA)

    1994-06-01

    In 1991, two hatcheries were built to provide a kokanee salmon and rainbow trout fishery for Lake Roosevelt as partial mitigation for the loss of anadromous salmon and steelhead caused by construction of Grand Coulee Dam. The Sherman Creek Hatchery, located on a tributary of Lake Roosevelt to provide an egg collection and imprinting site, is small with limited rearing capability. The second hatchery was located on the Spokane Indian Reservation because of a spring water source that supplied cold, pure water for incubating and rearing eggs.`The Spokane Tribal Hatchery thus serves as the production facility. Fish reared there are released into Sherman Creek and other tributary streams as 7-9 month old fry. However, to date, returns of adult fish to release sites has been poor. If hatchery reared kokanee imprint to the hatchery water at egg or swim up stages before 3 months of age, they may not be imprinting as 7-9 month old fry at the time of stocking. In addition, if these fish undergo a smolt phase in the reservoir when they are 1.5 years old, they could migrate below Grand Coulee Dam and out of the Lake Roosevelt system. In the present investigation, which is part of the Lake Roosevelt monitoring program to assess hatchery effectiveness, kokanee salmon were tested to determine if they experienced thyroxine-induced chemical imprinting and smoltification similar to anadromous salmonids. Determination of the critical period for olfactory imprinting was determined by exposing kokanee to different synthetic chemicals (morpholine or phenethyl alcohol) at different life stages, and then measuring the ability to discriminate the chemicals as sexually mature adults. Whole body thyroxine content and blood plasma thyroxine concentration was measured to determine if peak thyroid activity coincided with imprinting or other morphological, physiological or behavioral transitions associated with smoltification.

  18. The effects of simulated solar UVB radiation on early developmental stages of the Northwestern Salamander (Ambystoma gracile) from three lakes

    Science.gov (United States)

    Calfee, Robin D.; Little, Edward E.; Pearl, Christopher A.; Hoffman, Robert L.

    2010-01-01

    Solar ultraviolet radiation (UV) has received much attention as a factor that could play a role in amphibian population declines. UV can be hazardous to some amphibians, but the resultant effects depend on a variety of environmental and behavioral factors. In this study, the potential effects of UV on the Northwestern Salamander, Ambystoma gracile, from three lakes were assessed in the laboratory using a solar simulator. We measured the survival of embryos and the survival and growth of larvae exposed to four UV treatments in controlled laboratory studies, the UV absorbance of egg jelly, oviposition depths in the lakes, and UV absorbance in water samples from the three lakes. Hatching success of embryos decreased in the higher UV treatments as compared to the control treatments, and growth of surviving larvae was significantly reduced in the higher UVB irradiance treatments. The egg jelly exhibited a small peak of absorbance within the UVB range (290–320 nm). The magnitude of UV absorbance differed among egg jellies from the three lakes. Oviposition depths at the three sites averaged 1.10 m below the water surface. Approximately 66% of surface UVB radiation was attenuated at 10-cm depth in all three lakes. Results of this study indicate that larvae may be sensitive to UVB exposure under laboratory conditions; however, in field conditions the depths of egg deposition in the lakes, absorbance of UV radiation by the water column, and the potential for behavioral adjustments may mitigate severe effects of UV radiation.

  19. The Lake Ohrid Drilling Project: some initial interpretations of stable isotope data through the last 15 Marine Isotope Stages

    Science.gov (United States)

    Leng, Melanie; Lacey, Jack; Francke, Alexander; Wagner, Bernd; Zanchetta, Giovanni

    2015-04-01

    The SCOPSCO (Scientific Collaboration on Past Speciation Conditions in Lake Ohrid) project is an international research initiative to study the influence of major geological/environmental events on the biologic evolution of taxa. The target site for this study is Lake Ohrid, which is considered to be the oldest lake with continuous existence in Europe and which has more than 200 endemic species. The recovery of long sediment successions from Lake Ohrid is the basis for obtaining more precise information about the age and origin of the lake, and about the climatic and environmental history of the region including the history of Italian volcanic eruptions. The main SCOPSCO drilling campaign was carried out in 2013, and here we describe data from a 569 m core taken from centre of the lake. Initial data from borehole logging, core logging and geochemistry indicate that the sediment succession from this site covers more than 1.2 million years of Earth's history. Total carbon (TC) and Total Inorganic Carbon (TIC) content show that the amount of TIC is a proxy for short-term and long-term climate change (Vogel et al., 2010; Wagner et al., 2010). TIC is high during interglacials and primarily originates from calcite precipitated in the spring-summer in the epilimnion, when photoautotropic organisms assimilate CO2 utilising the Ca and bicarbonate from the karstic springs. During the glacials, carbonate is almost absent except from discrete siderite layers. TOC is very low throughout both the glacial and interglacial periods and reflects the oligotrophic conditions in the lake. The oxygen and carbon isotope composition of the endogenic carbonate has been shown to be a function of the balance between freshwater input by rivers and springs and evaporation of the lake water (Leng et al., 2010). Variations both within and between interglacials show climate variability including periods of exceptional aridity and potentially very low lake levels. These early findings suggest that

  20. Effects of simulated solar UVB radiation on early developmental stages of the northwestern salamander (Ambystoma gracile) from three lakes

    Science.gov (United States)

    Calfee, R.D.; Little, E.E.; Pearl, C.A.; Hoffman, R.L.

    2010-01-01

    Solar ultraviolet radiation (UV) has received much attention as a factor that could play a role in amphibian population declines. UV can be hazardous to some amphibians, but the resultant effects depend on a variety of environmental and behavioral factors. In this study, the potential effects of UV on the Northwestern Salamander, Ambystoma gracile, from three lakes were assessed in the laboratory using a solar simulator. We measured the survival of embryos and the survival and growth of larvae exposed to four UV treatments in controlled laboratory studies, the UV absorbance of egg jelly, oviposition depths in the lakes, and UV absorbance in water samples from the three lakes. Hatching success of embryos decreased in the higher UV treatments as compared to the control treatments, and growth of surviving larvae was significantly reduced in the higher UVB irradiance treatments. The egg jelly exhibited a small peak of absorbance within the UVB range (290-320 nm). The magnitude of UV absorbance differed among egg jellies from the three lakes. Oviposition depths at the three sites averaged 1.10 m below the water surface. Approximately 66 of surface UVB radiation was attenuated at 10-cm depth in all three lakes. Results of this study indicate that larvae may be sensitive to UVB exposure under laboratory conditions; however, in field conditions the depths of egg deposition in the lakes, absorbance of UV radiation by the water column, and the potential for behavioral adjustments may mitigate severe effects of UV radiation. Copyright 2010 Society for the Study of Amphibians and Reptiles.

  1. Evidence for millennial-scale climate change during marine isotope stages 2 and 3 at Little Lake, Western Oregon, U.S.A.

    Science.gov (United States)

    Grigg, L.D.; Whitlock, C.; Dean, W.E.

    2001-01-01

    Pollen and geochemical data from Little Lake, western Oregon, suggest several patterns of millennial-scale environmental change during marine isotope stage (MIS) 2 (14,100-27,600 cal yr B.P.) and the latter part of MIS 3 (27,600-42,500 cal yr B.P.). During MIS 3, a series of transitions between warm- and cold-adapted taxa indicate that temperatures oscillated by ca. 2??-4??C every 1000-3000 yr. Highs and lows in summer insolation during MIS 3 are generally associated with the warmest and coldest intervals. Warm periods at Little Lake correlate with warm sea-surface temperatures in the Santa Barbara Basin. Changes in the strength of the subtropical high and the jet stream may account for synchronous changes at the two sites. During MIS 2, shifts between mesic and xeric subalpine forests suggest changes in precipitation every 1000-3000 yr. Increases in Tsuga heterophylla pollen at 25,000 and 22,000 cal yr B.P. imply brief warmings. Minimum summer insolation and maximum global ice-volumes during MIS 2 correspond to cold and dry conditions. Fluctuations in precipitation at Little Lake do not correlate with changes in the Santa Barbara Basin and may be explained by variations in the strength of the glacial anticyclone and the position of the jet stream. ?? 2001 University of Washington.

  2. Miocene long-lived lake Pebas as a stage of mollusc radiations, with implications for landscape evolution in western Amazonia

    NARCIS (Netherlands)

    Wesselingh, F.P.

    2006-01-01

    The Miocene Pebas system was a huge (> 1 million km2) system of long-lived lakes and wetlands that occupied most of western Amazonia between c. 23 and 8 Ma. Remarkable endemic radiations of molluscs and ostracods occurred in the Pebas system. The continuity of many of the endemic lineages between c.

  3. Disponibilidad de arena para el refulado de las playas de Miramar y Chapadmalal, Argentina

    Directory of Open Access Journals (Sweden)

    FI Isla

    2003-09-01

    Full Text Available Las playas de Miramar se originaron por los aportes naturales transportados directamente como médanos transversales desde el oeste, aunque estas arenas son de origen marino que llegaron a la costa por la acción de olas. Cuando ese aporte de arena mermó debido a la forestación de los médanos del Vivero Ameghino, se debió recurrir a espigones rígidos, que luego debieron ser prolongados para mantener una anchura suficiente de las playas para los requerimientos balnearios. Hoy día el repoblamiento artificial resulta el único método factible de recuperar las playas desde los sectores sumergidos o desde médanos vecinos. Utilizando un sonar de barrido lateral y muestreos de arena se analizó la distribución y calidad de las arenas sumergidas como eventual fuente de alimentación de las playas de Miramar y Chapadmalal. Se estimaron factores de relleno y recurrencia en relación a la granulometría actual de estas playas. La playa sumergida está compuesta principalmente de arena muy fina y se extiende hasta una profundidad de 10-15 m, más allá de la cual se descubren afloramientos de limos entoscados hasta la profundidad de aproximadamente 20 metros. Otro sector arenoso se extiende a profundidades mayores y está dominado por fajas de arena orientadas hacia el NE. Lamentablemente, estas arenas son demasiado finas y por lo tanto no resultarían económicamente aptas para repoblar las playas de Miramar y Chapadmalal.

  4. Controls on the chemical composition of saline surface crusts and emitted dust from a wet playa in the Mojave Desert (USA)

    Science.gov (United States)

    Goldstein, Harland L.; Breit, George N.; Reynolds, Richard L.

    2017-01-01

    Saline-surface crusts and their compositions at ephemeral, dry, and drying lakes are important products of arid-land processes. Detailed understanding is lacking, however, about interactions among locally variable hydrogeologic conditions, compositional control of groundwater on vadose zone and surface salts, and dust composition. Chemical and physical data from groundwater, sediments, and salts reveal compositional controls on saline-surface crusts across a wet playa, Mojave Desert, with bearing on similar settings elsewhere. The compositions of chemically and isotopically distinctive shallow (elements in the vadose zone diminishes the concentrations of potentially toxic elements in surface salts, but creates a reservoir of these elements that may be brought to the surface during wetter conditions or by human disturbance. Selective wind-erosion loss of sulfate salts was identified by the compositional contrast between surface salt crusts and underlying groundwater. At the sub-basin scale, compositional links exist among groundwater, salt crusts, and dust from wet playas. Across the study basin, however, lateral variations in groundwater and solid-salt compositions are produced by hydrogeologic heterogeneity.

  5. THE EVOLUTION OF SMALL LAKE BASINS IN THE GOBI DESERT IN MONGOLIA

    Institute of Scientific and Technical Information of China (English)

    J.Grunert; C.Stolz; N.Hempelmann; A.Hilgers; D.Hulle; F.Lehmkuhl; T.Felauer; D.Dasch

    2009-01-01

    In order to investigate pluvial lakes in the Gobi two places were selected for field studies:Khongoryn Els in South-and Mongol Eis in West-Mongolia.In the eastern and central parts of Khongoryn gls two small endorheic basins,Bayan Tukhem and Khongoryn Gol depressions were studied.Pluvial lake deposits and beach ridges both supposedly mid-Holocene in age give evidence of a 9m and a 15m deep freshwater lake,respectively.Today both depressions are nearly dried out and exposed to wind deflation.A different situation was found at Uujin Sair river valley which cuts through the dune field at its lowest and narrowest(3 kin)part.Here,a 22.5 m thick fossil accumulation of at least 20 layers of fine sand (dune sand)alternating with silt(fluvial playa sediment)was exposed and OSL dated.12 dates ranging between 14ka and 17ka reveal the accumulation as Late Glacial which correlates well with the aridity at that time reported for Central Asia by several authors.Interpreting the dates it seems obvious that the whole sediment was quickly deposited in a period of about 16ka,and shortly after dissected by the Uujin Sair during a similar short time due to increasing humidity of the elimate.Another situation was found at the eastern rim of Mongol Els.Two rivers,Shurgiyn Gol and Zavran Gol are impinging here on the high dunes which have damed both rivers in the past.A younger,shallow lake existed during mid-Holocene (14C-dated to some 5.5ka)and a large,17m deep lake(14C-dated to some 39ka)probably during stage 4.Expected OSL dates will hopefully support this hypothesis.Anyhow,the palaeogeography of the dune field was different from today;it moved eastward daming the large river Shurgiyn Gol.

  6. Modeling sediment accumulation in North American playa wetlands in response to climate change, 1940-2100

    Science.gov (United States)

    Burris, Lucy; Skagen, Susan K.

    2013-01-01

    Playa wetlands on the west-central Great Plains of North America are vulnerable to sediment infilling from upland agriculture, putting at risk several important ecosystem services as well as essential habitats and food resources of diverse wetland-dependent biota. Climate predictions for this semi-arid area indicate reduced precipitation which may alter rates of erosion, runoff, and sedimentation of playas. We forecasted erosion rates, sediment depths, and resultant playa wetland depths across the west-central Great Plains and examined the relative roles of land use context and projected changes in precipitation in the sedimentation process. We estimated erosion with the Revised Universal Soil Loss Equation (RUSLE) using historic values and downscaled precipitation predictions from three general circulation models and three emissions scenarios. We calibrated RUSLE results using field sediment measurements. RUSLE is appealing for regional scale modeling because it uses climate forecasts with monthly resolution and other widely available values including soil texture, slope and land use. Sediment accumulation rates will continue near historic levels through 2070 and will be sufficient to cause most playas (if not already filled) to fill with sediment within the next 100 years in the absence of mitigation. Land use surrounding the playa, whether grassland or tilled cropland, is more influential in sediment accumulation than climate-driven precipitation change.

  7. Satellite Imagery Measures of the Astronomically Aligned Megaliths at Nabta Playa

    Science.gov (United States)

    Brophy, T. G.; Rosen, P. A.

    2003-12-01

    Astronomically aligned megalithic structures described in field reports (Wendorf, F. and Malville, J.M., The Megalith Alignments, pp.489-502 in Holocene Settlement of the Egyptian Sahara, Vol.I, 2001.) are identified in newly acquired georectified 60 cm panchromatic satellite imagery of Nabta Playa, southern Egypt. The satellite images allow refinement, often significant, of the reported locations of the megaliths. The report that the primary megalithic alignment was constructed to point to the bright star Sirius, circa 4,820 BC, is reconsidered in light of the satellite data, new field data, radiocarbon, lithostratigraphic and geochronologic data, and the playa sedimentation history. Other possible archaeoastronomical interpretations are considered for that alignment, including the three stars of Orion's Belt circa 6,270 BC that are also implicated in the small Nabta Playa `calendar circle'. Other new features apparent in the satellite imagery are also considered.

  8. Construcción de playas. Experiencias en España

    OpenAIRE

    París Solas, Carlos; Wibbelink, Hendrik; Basabe Criado, Juan Manuel

    1995-01-01

    Dentro de los programas de defensa, conservación y regeneración de la costa es cada vez más frecuente la utilización de aportaciones de materiales granulares (en particular, arena) para la regeneración de playas y la construcción de playas artificiales. Si este objetivo es deseable en sí mismo, como un medio más de conservación del entorno medio-ambiental, adquiere una significación especial en el caso de los países turísticos, como España, donde la disponibilidad de playas en condiciones ópt...

  9. Effectiveness of vegetation buffers surrounding playa wetlands at contaminant and sediment amelioration

    Science.gov (United States)

    Haukos, David A.; Johnson, Lacrecia A.; Smith, Loren M.; McMurry, Scott T.

    2016-01-01

    Playa wetlands, the dominant hydrological feature of the semi-arid U.S. High Plains providing critical ecosystem services, are being lost and degraded due to anthropogenic alterations of the short-grass prairie landscape. The primary process contributing to the loss of playas is filling of the wetland through accumulation of soil eroded and transported by precipitation from surrounding cultivated watersheds. We evaluated effectiveness of vegetative buffers surrounding playas in removing metals, nutrients, and dissolved/suspended sediments from precipitation runoff. Storm water runoff was collected at 10-m intervals in three buffer types (native grass, fallow cropland, and Conservation Reserve Program). Buffer type differed in plant composition, but not in maximum percent removal of contaminants. Within the initial 60 m from a cultivated field, vegetation buffers of all types removed >50% of all measured contaminants, including 83% of total suspended solids (TSS) and 58% of total dissolved solids (TDS). Buffers removed an average of 70% of P and 78% of N to reduce nutrients entering the playa. Mean maximum percent removal for metals ranged from 56% of Na to 87% of Cr. Maximum removal was typically at 50 m of buffer width. Measures of TSS were correlated with all measures of metals and nutrients except for N, which was correlated with TDS. Any buffer type with >80% vegetation cover and 30–60 m in width would maximize contaminant removal from precipitation runoff while ensuring that playas would continue to function hydrologically to provide ecosystem services. Watershed management to minimize erosion and creations of vegetation buffers could be economical and effective conservation tools for playa wetlands.

  10. Disponibilidad de arena para el refulado de las playas de Miramar y Chapadmalal, Argentina

    OpenAIRE

    FI Isla

    2003-01-01

    Las playas de Miramar se originaron por los aportes naturales transportados directamente como médanos transversales desde el oeste, aunque estas arenas son de origen marino que llegaron a la costa por la acción de olas. Cuando ese aporte de arena mermó debido a la forestación de los médanos del Vivero Ameghino, se debió recurrir a espigones rígidos, que luego debieron ser prolongados para mantener una anchura suficiente de las playas para los requerimientos balnearios. Hoy día el repoblamient...

  11. Assessing Nebraska playa wetland inundation status during 1985-2015 using Landsat data and Google Earth Engine.

    Science.gov (United States)

    Tang, Zhenghong; Li, Yao; Gu, Yue; Jiang, Weiguo; Xue, Yuan; Hu, Qiao; LaGrange, Ted; Bishop, Andy; Drahota, Jeff; Li, Ruopu

    2016-12-01

    Playa wetlands in Nebraska provide globally important habitats for migratory waterfowl. Inundation condition is an important indicator of playa wetland functionality. However, there is a lack of long-term continuous monitoring records for playa wetlands. The objective of this study was to determine a suitable index for Landsat images to map the playa inundation status in March and April during 1985-2015. Four types of spectral indices-negative normalized vegetation index, Normalized Difference Water Index (NDWI), modified NDWI, and Tasseled Cap Wetness-Greenness Difference (TCWGD)-were evaluated to detect playa inundation conditions from Landsat images. The results indicate that the TCWGD is the most suitable index for distinguishing playa inundation status. By using Landsat images and Google Earth Engine, we mapped the spring inundation condition of Nebraska playas during 1985-2015. The results show that the total inundated areas were 176.79 km(2) in spring migratory season, representing 18.92% of the total area of playa wetlands. There were 9898 wetlands inundated at least once in either March or April during the past 30 years, representing 29.41% of a total of 33,659 historical wetlands. After comparing the historical hydric soil footprints and the inundated areas, the results indicate that the hydrological conditions of the majority of playas in Nebraska have changed. The inundated wetlands are candidates for protection and/or partial restoration, and the un-inundated wetlands need more attention for wetland restoration. Wetlands in areas enrolled in conservation easements had a significantly high level of playa inundation status than non-conserved wetlands during spring migratory seasons in the past decades.These conservation easements only count for 4.29% of the total footprint areas, but they have contributed 20.82% of the inundation areas in Nebraska during the past 30 years.

  12. Hydrologic budget of the late Oligocene Lake Creede and the evolution of the upper Rio Grande drainage system

    Science.gov (United States)

    Barton, Paul B.; Steven, Thomas A.; Hayba, Daniel O.

    2000-01-01

    The filling history, hydrologic budget, and geomorphic development of ancient Lake Creede and its tributary basin are evaluated to determine the factors that controlled its character. The lake filled the Creede caldera that formed in the late Oligocene as a consequence of the eruption of the Snowshoe Mountain Tuff. The caldera's sedimentary fill accumlated to a depth of about 1.26 km and had a volume of about 89 km3. The highest lake level was ~3300 m (10,800 ft) present altitude before it drained eastward across a broad volcanic plateau as the ancestral Rio Grande. A tributary canyon several hundred meters deep was cut into hard rhyolite in the north wall of the caldera before the lake was more than half full; its presence demonstrates that ancient Lake Creede filled slowly and thus occupied a long-lived, closed basin. The slow filling rate is incompatible with the present water flux through the Creede caldera basin, because such a flow would fill the basin geologically instantaneously. This mismatch, together with the recognition that the Oligocene climate was similar to that of today, forces the reexamination of the hydrologic and geomorphic history of the caldera. That appraisal shows that the caldera cannot have resurged rapidly immediately after caldera collapse, and that ancient watershed must have been lass than half as large as the present upper Rio Grande basin. The ancient lake had a more or less constant surface area of about 200 km2 that approximated a steady-state condition between inflow and evaporation. Although the lake level fluctuated with climatic variations, its surface elevation steadily climbed as sediment accumulated, accelerating as resurgance and dome growth usurped spacewithin the basin. It could have had one playa stage early in its development and another after the basin had nearly filled with sediment, but there is no direct evidence for either. At least the lower half of the sedimentary column (the part sampled by the scientific

  13. Water-Chemistry Evolution and Modeling of Radionuclide Sorption and Cation Exchange during Inundation of Frenchman Flat Playa

    Energy Technology Data Exchange (ETDEWEB)

    Hershey, Ronald; Cablk, Mary; LeFebre, Karen; Fenstermaker, Lynn; Decker, David

    2013-08-01

    Atmospheric tests and other experiments with nuclear materials were conducted on the Frenchman Flat playa at the Nevada National Security Site, Nye County, Nevada; residual radionuclides are known to exist in Frenchman Flat playa soils. Although the playa is typically dry, extended periods of winter precipitation or large single-event rainstorms can inundate the playa. When Frenchman Flat playa is inundated, residual radionuclides on the typically dry playa surface may become submerged, allowing water-soil interactions that could provide a mechanism for transport of radionuclides away from known areas of contamination. The potential for radionuclide transport by occasional inundation of the Frenchman Flat playa was examined using geographic information systems and satellite imagery to delineate the timing and areal extent of inundation; collecting water samples during inundation and analyzing them for chemical and isotopic content; characterizing suspended/precipitated materials and archived soil samples; modeling water-soil geochemical reactions; and modeling the mobility of select radionuclides under aqueous conditions. The physical transport of radionuclides by water was not evaluated in this study. Frenchman Flat playa was inundated with precipitation during two consecutive winters in 2009-2010 and 2010-2011. Inundation allowed for collection of multiple water samples through time as the areal extent of inundation changed and ultimately receded. During these two winters, precipitation records from a weather station in Frenchman Flat (Well 5b) provided information that was used in combination with geographic information systems, Landsat imagery, and image processing techniques to identify and quantify the areal extent of inundation. After inundation, water on the playa disappeared quickly, for example, between January 25, 2011 and February 10, 2011, a period of 16 days, 92 percent of the areal extent of inundation receded (2,062,800 m2). Water sampling provided

  14. Sensitivity of lake sturgeon (Acipenser fulvescens) early life stages to 2,3,7,8-tetrachlorodibenzo-P-dioxin and 3,3′,4,4′,5-pentachlorobiphenyl

    Science.gov (United States)

    Tillitt, Donald E.; Buckler, Justin A.; Nicks, Diane; Candrl, James; Claunch, Rachel; Gale, Robert W.; Puglis, Holly J.; Little, Edward E.; Linbo, Tiffany L.; Baker, Mary

    2017-01-01

    The aquatic food web of the Great Lakes has been contaminated with polychlorinated biphenyls (PCBs) since the mid-20th century. Threats of PCB exposures to long-lived species of fish, such as lake sturgeon (Acipenser fulvescens), have been uncertain because of a lack of information on the relative sensitivity of the species. The objective of the present study was to evaluate the sensitivity of early–life stage lake sturgeon to 3,3′,4,4′,5-pentachlorobiphenyl (PCB-126) or 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) exposure. Mortality, growth, morphological and tissue pathologies, swimming performance, and activity levels were used as assessment endpoints. Pericardial and yolk sac edema, tubular heart, yolk sac hemorrhaging, and small size were the most commonly observed pathologies in both TCDD and PCB-126 exposures, beginning as early as 4 d postfertilization, with many of these pathologies occurring in a dose-dependent manner. Median lethal doses for PCB-126 and TCDD in lake sturgeon were 5.4 ng/g egg (95% confidence interval, 3.9–7.4 ng/g egg) and 0.61 ng/g egg (0.47–0.82 ng/g egg), respectively. The resulting relative potency factor for PCB-126 (0.11) was greater than the World Health Organization estimate for fish (toxic equivalency factor = 0.005), suggesting that current risk assessments may underestimate PCB toxicity toward lake sturgeon. Swimming activity and endurance were reduced in lake sturgeon survivors from the median lethal doses at 60 d postfertilization. Threshold and median toxicity values indicate that lake sturgeon, like other Acipenser species, are more sensitive to PCB and TCDD than the other genus of sturgeon, Scaphirhynchus, found in North America. Indeed, lake sturgeon populations in the Great Lakes and elsewhere are susceptible to PCB/TCDD-induced developmental toxicity in embryos and reductions in swimming performance.

  15. Gestión del uso y explotación de las playas

    Directory of Open Access Journals (Sweden)

    Víctor Yepes Piqueras

    2007-01-01

    Full Text Available La adopción voluntaria de sistemas de gestión de la calidad y del medio ambiente en las playas turísticas supone un cambio sustancial en el enfoque de la ordenación de los usos y la explotación de estos espacios litorales por parte de algunos municipios. Tras examinar las debilidades de la gestión habitual de las playas, se recogen y consideran las distintas normas y sistemas de gestión aplicables. Este nuevo enfoque es necesario para mantener los beneficios económicos y sociales a largo plazo que proporciona el turismo litoral. Un análisis de la evolución de los certificados de gestión en las playas de la Comunidad Valenciana permite comprobar la aplicabilidad de estos sistemas y la compatibilidad entre ellos. La gestión racional en el uso de las playas, apoyada en estos nuevos instrumentos, deberá satisfacer a todas las partes interesadas: los turistas, la población local, el medio ambiente y las generaciones futuras.

  16. Biophysical Controls over Carbon and Nitrogen Stocks in Desert Playa Wetlands

    Science.gov (United States)

    McKenna, O. P.; Sala, O. E.

    2014-12-01

    Playas are ephemeral desert wetlands situated at the bottom of closed catchments. Desert playas in the Southwestern US have not been intensively studied despite their potential importance for the functioning of desert ecosystems. We want to know which geomorphic and ecological variables control of the stock size of soil organic carbon, and soil total nitrogen in playas. We hypothesize that the magnitude of carbon and nitrogen stocks depends on: (a) catchment size, (b) catchment slope, (d) catchment vegetation cover, (e) bare-ground patch size, and (f) catchment soil texture. We chose thirty playas from across the Jornada Basin (Las Cruces, NM) ranging from 0.5-60ha in area and with varying catchment characteristics. We used the available 5m digital elevation map (DEM) to calculate the catchment size and catchment slope for these thirty playas. We measured percent cover, and patch size using the point-intercept method with three 10m transects in each catchment. We used the Bouyoucos-hydrometer soil particle analysis to determine catchment soil texture. Stocks of organic carbon and nitrogen were measured from soil samples at four depths (0-10 cm, 10-30 cm, 30-60 cm, 60-100 cm) using C/N combustion analysis. In terms of nitrogen and organic carbon storage, we found soil nitrogen values in the top 10cm ranging from 41.963-214.365 gN/m2, and soil organic carbon values in the top 10cm ranging from 594.339-2375.326 gC/m2. The results of a multiple regression analysis show a positive relationship between catchment slope and both organic carbon and nitrogen stock size (nitrogen: y= 56.801 +47.053, R2=0.621; organic carbon: y= 683.200 + 499.290x, R2= 0.536). These data support our hypothesis that catchment slope is one of factors controlling carbon and nitrogen stock in desert playas. We also applied our model to the 69 other playas of the Jornada Basin and estimated stock sizes (0-10cm) between 415.07-447.97 Mg for total soil nitrogen and 4627.99-5043.51 Mg for soil organic

  17. Presencia de microplásticos en cuatro playas arenosas de Perú

    Directory of Open Access Journals (Sweden)

    Sara Purca

    2017-04-01

    Full Text Available Se presenta el número y peso por metro cuadrado de fragmentos de microplásticos presentes en cuatro playas arenosas de la costa peruana. Las muestras fueron colectadas entre junio de 2014 y mayo 2015. Fragmentos de plástico duro mayores a 1 mm fueron encontrados en más del 80% de las muestras de las cuatro playas. La playa Costa Azul (~ 12°S presentó 522 fragmentos por metro cuadrado (items/m2 de microplásticos, de los cuales, 463.33 items/m2 y 2.6 g/m2 fueron plásticos duros. La playa Albúfera de Medio Mundo (~ 11°S presentó el menor número y peso de microplásticos (4.67 items/m2 y 0.50 g/m2. Una muestra aleatoria de la playa Costa Azul fue analizada por el espectroscopio FT-IR. Se encontró 5 fragmentos con poliuretano (PE, dos fragmentos con polipropileno (PP y un fragmento con estireno (EPS. Pocos estudios mencionan al plástico duro como la mayor fracción de los microplásticos, se sugiere nuevas fuentes de intrusión y vías de microbasura en los hábitas, los cuales podrían estar afectando desde la base de trama trófica marina en el Perú.

  18. Geochemical controls of groundwaters upwelling in saline environments: Case study the discharge playa of Sidi El Hani (Sahel, Tunisia)

    Science.gov (United States)

    Tagorti, Mohamed Ali; Essefi, Elhoucine; Touir, Jamel; Guellala, Rihab; Yaich, Chokri

    2013-10-01

    Within the discharge playa of Sidi El Hani, the surrounding aquifers converge due to uprising underground waters. The Principal Component Analysis proves that the fluid density is inversely influenced by the rainfall and has a reciprocal effect with evaporation. This parameter is governed by uprising groundwaters and the convergence of waters and inflow in the sabkha result in a geochemical exceptionality. The fluid density maintains high values during the year, the modeling of which shows a third sinusoidal distribution. This model remains stable along a span of time because the surrounding aquifer feeds the discharge playa by a continuous salty water flow. In general, waters in the majority of drills surrounding the discharge playa have the same facies which is mainly made up of water charged with Na+ and Cl-. A sample from the northeast of discharge playa shows a geochemical similarity with two wells located in its vicinity.

  19. Strontium isotope geochemistry of soil and playa deposits near Yucca Mountain, Nevada

    Energy Technology Data Exchange (ETDEWEB)

    Marshall, B.D.; Mahan, S.A. [Geological Survey, Denver, CO (United States)

    1994-12-31

    The isotopic composition of strontium contained in the carbonate fractions of soils provides an excellent tracer which can be used to test models for their origin. This paper reports data on surface coatings and cements, eolian sediments, playas and alluvial fan soils which help to constrain a model for formation of the extensive calcretes and fault infillings in the Yucca Mountain region. The playas contain carbonate with a wide range of strontium compositions; further work will be required to fully understand their possible contributions to the pedogenic carbonate system. Soils from an alluvial fan to the west of Yucca Mountain show that only small amounts of strontium are derived from a fan draining a carbonate terrane have strontium component. Although much evidence points to an eolian source for at least some of the strontium in the pedogenic carbonates near Yucca Mountain, an additional component or past variation of strontium composition in the eolian source is required to model the pedogenic carbonate system.

  20. El turismo cultural y el de sol y playa: ¿sustitutivos o complementarios?

    Directory of Open Access Journals (Sweden)

    Antonio García Sánchez

    2003-01-01

    Full Text Available La demanda del mercado turístico desde hace unos años, manifiesta una tendencia creciente de búsqueda de nuevas satisfacciones en respuesta a expectativas de ocio y esparcimiento: una combinación de vacaciones, turismo y enriquecimiento cultural, en una actitud mucho más activa y participativa. Aunque el turismo de sol y playa y el turismo cultural aparecen, inicialmente, como dos productos dirigidos a segmentos diferentes del mercado turístico, un análisis de las nuevas tendencias observadas en la demanda turística y del producto «sol y playa» en particular (fraccionamiento de vacaciones, evolución de la ocupación durante meses menos tradicionales, nivel cultural, inquietudes y preferencias de turistas, etc. denota que existen complementariedades crecientes entre ambos productos que, adecuadamente tratadas, pueden reportar beneficios para ambos tipos de destino.

  1. Some precisions on the use of the term playa in the geologic literature

    OpenAIRE

    Arche, Alfredo

    2008-01-01

    The term playa has been used in the geomorphological and sedimentological literature for more than a century, but there is still considerable confusion around its precise definition and the English equivalent or lack of it. A revision of the original descriptions and some recent general papers on this topic shows that the geomorphic approach to its definition, that is, its topography and relationship, or lack of it, to a fluvial network is totally insufficient for its distinction fro...

  2. La calidad ambiental como factor competitivo de los destinos tradicionales de sol y playa

    Directory of Open Access Journals (Sweden)

    Ma Dolores Ponce Sánchez

    2004-01-01

    Full Text Available La preocupación ambiental y las exigencias de calidad, al respecto, se han convertido en un valor global de cualquier destino turístico, independientemente del perfil socioeconómico de su demanda. En este sentido, se pretende subrayar su importante papel en materia de cualificación, diversificación y mejora de la competitividad en los destinos tradicionales de sol y playa.

  3. Miocene alluvial fan-alkaline playa lignite-trona bearing deposits from an inverted basin in Anatolia: sedimentology and tectonic controls on deposition

    Science.gov (United States)

    İnci, Uǧur

    1991-04-01

    During the Middle through Late Miocene, over 1200 m of clastics, carbonates and evaporites accumulated in the depositional basin situated in northwestern Ankara province of Central Anatolia. Detailed stratigraphic and sedimentological analyses of the exposed sequence exhibits three major facies: (1) lower alluvial, (2) upper alluvial, and (3) lacustrine. The lower alluvial facies consists primarily of volcaniclastic debris-flow, boulder and channel conglomerate, sandstone, siltstone, mudstone and two lignite horizons. These rock assemblages were deposited in alluvial fans and a braided-river system. The lower and upper lignite seams were laid down in swamps and lake-margin mud-flat environments associated with this river system. The upper alluvial facies is characterized by red conglomerate, fine-grained and cross-bedded sandstone, mudstone and calcareous mudstone units. The dominant depositional environments are interpreted to be alluvial fan, braided-river, and mud-flat. The base of the lacustrine deposits interfingers with the lower alluvial facies and consists of dolomitic claystone, bituminous shale, trona and intraformational conglomerate lithofacies. The sedimentary features of the dolomitic claystone and trona lithofacies suggest deposition in a playa-lake type environment. The bituminous shale is a transgressive deposit laid down in a shallow, but expanded lake environment. Sedimentological and structural characteristics of the intraformational conglomerate lithofacies indicate synsedimentary tectonism, intrabasinal erosion, redeposition and sediment selection toward the deposition centre of the lake environment. The green claystone lithofacies has three units: (a) the claystone-bedded chert-analcitized tuff alternation and siliceous carbonate lithofacies of the lacustrine system, deposited in a perennial lake environment; (b) montmorillonitic olive-green claystone containing mud-cracks, ripple mark and desiccation cracks filled by gypsum, deposited in a

  4. Sliding rocks on Racetrack Playa, Death Valley National Park: first observation of rocks in motion.

    Science.gov (United States)

    Norris, Richard D; Norris, James M; Lorenz, Ralph D; Ray, Jib; Jackson, Brian

    2014-01-01

    The engraved trails of rocks on the nearly flat, dry mud surface of Racetrack Playa, Death Valley National Park, have excited speculation about the movement mechanism since the 1940s. Rock movement has been variously attributed to high winds, liquid water, ice, or ice flotation, but has not been previously observed in action. We recorded the first direct scientific observation of rock movements using GPS-instrumented rocks and photography, in conjunction with a weather station and time-lapse cameras. The largest observed rock movement involved > 60 rocks on December 20, 2013 and some instrumented rocks moved up to 224 m between December 2013 and January 2014 in multiple move events. In contrast with previous hypotheses of powerful winds or thick ice floating rocks off the playa surface, the process of rock movement that we have observed occurs when the thin, 3 to 6 mm, "windowpane" ice sheet covering the playa pool begins to melt in late morning sun and breaks up under light winds of -4-5 m/s. Floating ice panels 10 s of meters in size push multiple rocks at low speeds of 2-5 m/min. along trajectories determined by the direction and velocity of the wind as well as that of the water flowing under the ice.

  5. Sliding rocks on Racetrack Playa, Death Valley National Park: first observation of rocks in motion.

    Directory of Open Access Journals (Sweden)

    Richard D Norris

    Full Text Available The engraved trails of rocks on the nearly flat, dry mud surface of Racetrack Playa, Death Valley National Park, have excited speculation about the movement mechanism since the 1940s. Rock movement has been variously attributed to high winds, liquid water, ice, or ice flotation, but has not been previously observed in action. We recorded the first direct scientific observation of rock movements using GPS-instrumented rocks and photography, in conjunction with a weather station and time-lapse cameras. The largest observed rock movement involved > 60 rocks on December 20, 2013 and some instrumented rocks moved up to 224 m between December 2013 and January 2014 in multiple move events. In contrast with previous hypotheses of powerful winds or thick ice floating rocks off the playa surface, the process of rock movement that we have observed occurs when the thin, 3 to 6 mm, "windowpane" ice sheet covering the playa pool begins to melt in late morning sun and breaks up under light winds of -4-5 m/s. Floating ice panels 10 s of meters in size push multiple rocks at low speeds of 2-5 m/min. along trajectories determined by the direction and velocity of the wind as well as that of the water flowing under the ice.

  6. Early-stage rifting in the southwest East African Rift: Insights from new reflection seismic data from Lakes Tanganyika and Malawi (Nyasa)

    Science.gov (United States)

    Scholz, C. A.; Wood, D. A.; Shillington, D. J.; McCartney, T.; Accardo, N. J.

    2015-12-01

    The western branch of the East African Rift is characterized by modest amounts of mainly amagmatic extension; deeply-subsided, fault-controlled basins; and large-magnitude, deep seismicity. Lakes Tanganyika and Malawi are two of the world's largest lakes, with maximum water depths of 1450 and 700 m respectively. Newly acquired seismic reflection data, along with newly reprocessed legacy data reveal thick sedimentary sections, in excess of 5 km in some localities. The 1980's vintage legacy data from Project PROBE have been reprocessed through pre-stack depth migration in Lake Tanganyika, and similar reprocessing of legacy data from Lake Malawi is forthcoming. New high-fold and large-source commercial and academic data have recently been collected in southern Lake Tanganyika, and in the northern and central basins of Lake Malawi as part of the 2015 SEGMeNT project. In the case of Lake Tanganyika, new data indicate the presence of older sediment packages that underlie previously identified "pre-rift" basement (the "Nyanja Event"). These episodes of sedimentation and extension may substantially predate the modern lake. These deep stratal reflections are absent in many localites, possibly on account of attenuation of the acoustic signal. However in one area of southern Lake Tanganyika, the newly-observed deep strata extend axially for ~70 km, likely representing deposits from a discrete paleolake. The high-amplitude Nyanja Event is interpreted as the onset of late-Cenozoic rifting, and the changing character of the overlying depositional sequences reflects increasing relief in the rift valley, as well as the variability of fluvial inputs, and the intermittent connectivity of upstream lake catchments. Earlier Tanganyika sequences are dominated by shallow lake and fluvial-lacustrine facies, whereas later sequences are characterized by extensive gravity flow deposition in deep water, and pronounced erosion and incision in shallow water depths and on littoral platforms. The

  7. Investigationof Clay Mineralogy, Micromorphology and Evolution of Soils in Bajestan Playa

    Directory of Open Access Journals (Sweden)

    Mohammad Ghasemzadeh Ganjehie

    2017-03-01

    Full Text Available Introduction: Playa is one of the most important landscapes in arid regions which covers about 1% of the world's total land area. Study of playas is important from different points of view especially pedology, sedimentology, mineralogy, environmental geology, groundwater and surface water chemistry. More than 60 playas have been identified in Iran. Considering the fact that playas and surrounding landforms are important archive of landscape evolution and paleoenvironmental variations, it seems that less attention has been paid to them so far. Soils are known as indicators of the landscapes evolution. Previous studies in arid regions of Iran imply different periods of deposition and soil formation in playa and alluvial fans or pediments. Bajestan playa is one of the known playa in northeastern Iran, and the largest clay flat exists in this playa. There is no information on the soils and their evolution in Bajestan playa. The objective of this study were to 1 identify the soils in different landforms along a transect from alluvial fan to clay in Bajestan playa 2 determine the morphological, micromorphological and mineralogical characteristics of these soils 3 determine the periods of soil and landform evolution and 4 comparison of soils evolution of the study area to other arid regions of Iran. Material and Methods: The study area of approximately 20000 hectares is located in southeastern of KhorasanRazavi province. The climate of the study area is hot and dry with mean annual temperature and rainfall of 17.3 °C and 193 mm, respectively. Soil moisture regime is aridic with subdivisions of weak aridic and soil temperature regime is thermic. Firstly, landforms and geomorphic surfaces of the study area were recognized based on Google Earth images interpretations and field observations. Four main landforms were recognized in the study area. The landforms from north to the south of the study area were alluvial fan, intermediate alluvial fan- clay flat

  8. From detachment to transtensional faulting: A model for the Lake Mead extensional domain based on new ages and correlation of subbasins

    Science.gov (United States)

    Beard, L.; Umhoefer, P. J.; Martin, K. L.; Blythe, N.

    2007-12-01

    New studies of selected basins in the Miocene extensional belt of the northern Lake Mead domain suggest a new model for the early extensional history of the region (lower Horse Spring Formation and correlative strata). Critical data are from (i) Longwell Ridges area west of Overton Arm and within the Lake Mead fault system, (ii) Salt Spring Wash basin in the hanging wall of the South Virgin-White Hills detachment (SVWHD) fault, and (iii) previously studied subbasins of the south Virgin Mountains in the Gold Butte step-over region. The basins and faulting patterns suggest two stages of basin development related to two distinct faulting episodes, an early period of detachment faulting followed by a switch to faulting mainly along the Lake Mead transtensional fault system while detachment faulting waned. Apatite fission track ages suggest the footwall block of the SVWHD was cooling at 18-17 Ma, but the only evidence for basin deposition at that time is in the Gold Butte step-over where slow rates of sedimentation and facies patterns make faulting on the north side of the Gold Butte block ambiguous. The first basin stage was ca. 16.5 to 15.5 Ma, during which there was slow to moderate faulting and subsidence in a basin along the SVWHD and north of Gold Butte block in the Gold Butte step-over basin; the step- over basin had complex fluvial and lacustrine facies and was synchronous with landslides and debris flows in front of the SVWHD. At ca. 15.5-14.5 Ma, there was a [dramatic] increase in sedimentation rate related to formation of the Gold Butte fault, a change from lacustrine to widespread fluvial, playa, and local landslide facies in the step-over basin, and the peak of exhumation and faulting rates on the SVWHD. The simple step-over basin broke up into numerous subbasins [at[ as initial faults of the Lake Mead fault system formed. From 14.5 to 14.0 Ma, there was completion of a major change from dominantly detachment faulting to dominantly transtensional faulting

  9. [Reef fishes community structure of Playa Mero, Parque Nacional Morrocoy, Venezuela].

    Science.gov (United States)

    Rodríguez, J; Villamizar, E

    2000-12-01

    The coral reef fish community was studied in Playa Mero, Morrocoy National Park, after the mass mortality of January, 1996 with a systematic sampling design. Transects and quadrates were used for corals, and a visual census for fishes. The coral community is highly disturbed with extensive areas of dead coral covered by algae, and low coverage and richness of coral species, gorgonians, sponges and briozooans. These factors have generated a relatively homogeneous environment with respect to the fish community, which was dominated by Scaridae and Pomacentridae that represented 75% of fish. Dominant fishes were mainly herbivorous (75.4% of all fish) apparently because of the disturbance that caused the settling of algae.

  10. Turismo en Playa del Carmen - México. Impactos socioculturales en la Colonia Colosio

    OpenAIRE

    2010-01-01

    El presente trabajo muestra los resultados de un estudio exploratorio de tipo cualitativo realizado en una colonia del destino turístico mundialmente conocido como Playa del Carmen, en el Caribe mexicano. La colonia Colosio fue fundada por una invasión en terrenos ejidales. Se trataba de personas en busca de un lugar para vivir cerca de los empleos que el destino turístico estaba ofreciendo. Esta situación fue particularmente interesante, pues las investigaciones realizadas sobre los impactos...

  11. Relevamientos semicuantitativo para el estudio de la morfología de playa

    Directory of Open Access Journals (Sweden)

    Angel Marcos

    2009-12-01

    Full Text Available El cambio climático global y sus efectos sobre las ambientalmente sensibles áreas costeras han llevado, tanto a los organismos científicos como económicos, a poner en ejecución planes de manejo costero. Un punto débil de este esquema es la falta de datos estadísticos, sobre todo en países del llamado Tercer Mundo, que por sus características económicas no destinan fondos para este tipo de estudio. Es por ello interesante ejecutar metodologías de relevamiento de bajo costo, accesibles aún a personas con escaso conocimiento técnico para obtener resultados que puedan servir para resolver esta problemática. Es así que se hicieron experiencias con una metodología basada en un relevamiento semicuantitativo de playas, adaptado a las condiciones del medio en la costa de Monte Hermoso. En dicha localidad, en base a estudios previos se posee un conocimiento de sus materiales y su dinámica, tanto de la playa como del mar y de su clima. Periódicamente, con un relevamiento expeditivo se pueden realizar perfiles topográficos de playa, mientras que observaciones oceanográficas y climáticas con métodos convencionales, son importantes para la comprensión de los procesos costeros que generan las variaciones morfológicas de la playa. La metodología se basa en un relevamiento descriptivo semicuantitativo, que brinda un caudal de información confiable y permite inferir el comportamiento de la playa en función del tiempo. Se realizan bosquejos topográficos de sectores definidos de la playa, volcando la información con una simbología preestablecida, indicando la orientación de barras, canales, afloramientos, corrientes de flujo, etc. Las dimensiones son estimadas según una grilla métrica. La grilla referenciada se construye con elementos de fácil reconocimiento, presentes en la costa, las que luego se identifican en campañas sucesivas a los efectos de comparar los cambios sufridos por la playa durante un período determinado. Los

  12. Mapas de inundación por tsunamis en Playas del Coco y Puntarenas, Costa Rica

    OpenAIRE

    Zamora Sauma, Natalia; Fernández Arce, Mario

    2010-01-01

    La presente investigación presenta algunos de los resultados obtenidos por el proyecto "Mapa de inundación por tsunamis para Costa Rica, primera fase, Puntarenas y Playas del Coco". Muestra los resultados obtenidos con respecto a simulaciones realizadas. Explica información del ambiente tectónico de la zona. Finalmente, expone algunas de las acciones de reducción del riesgo de inundación por tsunami y mitigación This investigation includes some of the results obtained in the project "Floo...

  13. Turismo en Playa del Carmen - México. Impactos socioculturales en la Colonia Colosio

    OpenAIRE

    Martha Marivel Mendoza Ontiveros

    2010-01-01

    El presente trabajo muestra los resultados de un estudio exploratorio de tipo cualitativo realizado en una colonia del destino turístico mundialmente conocido como Playa del Carmen, en el Caribe mexicano. La colonia Colosio fue fundada por una invasión en terrenos ejidales. Se trataba de personas en busca de un lugar para vivir cerca de los empleos que el destino turístico estaba ofreciendo. Esta situación fue particularmente interesante, pues las investigaciones realizadas sobre los impactos...

  14. Philopatry in a changing world: Response of Pink-footed Geese Anser brachyrhynchus to the loss of a key autumn staging area due to restoration of Filsø Lake, Denmark

    DEFF Research Database (Denmark)

    Clausen, Kevin; Madsen, Jesper

    2016-01-01

    to the sudden loss of a major autumn staging area along their migration corridor, Filsø in Denmark, which followed the re-establishment of a former lake on open arable land serving as foraging site to tens of thousands of geese. Comparisons of goose usage before and after the restoration event revealed that 1...... to alter site use allows a swift response to rapidly changing environmental conditions. This might above all relate to the agricultural habitat use of this species, leaving them plenty of alternatives in the modern Danish landscape....

  15. Playa Soil Moisture and Evaporation Dynamics During the MATERHORN Field Program

    Science.gov (United States)

    Hang, Chaoxun; Nadeau, Daniel F.; Jensen, Derek D.; Hoch, Sebastian W.; Pardyjak, Eric R.

    2016-06-01

    We present an analysis of field data collected over a desert playa in western Utah, USA in May 2013, the most synoptically active month of the year, as part of the Mountain Terrain Atmospheric Modeling and Observations (MATERHORN) program. The results show that decreasing surface albedo, decreasing Bowen ratio and increasing net radiation with increasing soil moisture sustained a powerful positive feedback mechanism promoting large evaporation rates immediately following rain events. Additionally, it was found that, while nocturnal evaporation was negligible during dry periods, it was quite significant (up to 30 % of the daily cumulative flux) during nights following rain events. Our results further show that the highest spatial variability in surface soil moisture is found under dry conditions. Finally, we report strong spatial heterogeneities in evaporation rates following a rain event. The cumulative evaporation for the different sampling sites over a five-day period varied from ≈ 0.1 to ≈ 6.6 mm. Overall, this study allows us to better understand the mechanisms underlying soil moisture dynamics of desert playas as well as evaporation following occasional rain events.

  16. Las playas en la gestión sostenible del litoral

    Directory of Open Access Journals (Sweden)

    Víctor Yepes Piqueras

    1999-01-01

    Full Text Available La playa constituye uno de los activos medioambientales más importantes de los recursos costeros. No sólo acostumbra a ser la base de la actividad turística, de especial relevancia en muchos países, sino que es soporte de una gran riqueza biológica y es un instrumento eficaz a la hora de llevar a cabo una política de protección de costas. El artículo repasa las características de los recursos costeros y cómo la gestión integrada del litoral puede ser una de las claves del desarrollo sostenible de actividades tales como la turística. Se reflexiona sobre los nuevos enfoques de la gestión empresarial basados fundamentalmente en la satisfacción del cliente y su aplicación al litoral. Esta nueva filosofía obliga a la adopción de una nueva estructura de gestión y justifica un replanteamiento en el modo de entender nuestras playas

  17. Playa Del Rey oil field, Los Angeles County, California-- natural gas storage

    Energy Technology Data Exchange (ETDEWEB)

    Barnds, R.M.

    1968-01-01

    The Playa del Rey oil field is on Santa Monica Bay, about 15 miles SW. of Los Angeles. The sedimentary rocks of the field were deposited on the flanks and over the ridge of an erosional surface of Franciscan schist. A NW.-trending anticline resulted from deposition and compaction over the ridge. An apron of schistose clastic material was deposited in the littoral zone at the base of the ridge and in embayments formed by the lateral channels. Conformably overlying the basal conglomerate (productive lower zone) and unconformably overlying the schist is a dark brown, compact shale with abundant small lenticular streaks and nodules of calcium phosphate. The rest of the Miocene rock column is composed of about 500 ft of hard, compact black shale and sandy shale, which is conformably overlain by the typical Los Angeles-basin Pliocene and Pleistocene rocks. The upper oil zone is in the lower Pliocene. The Playa del Rey Field is productive from both the lower zone and from sedimentary rocks of the anticline. There are widely varied porosity and permeability values throughout the Del Rey Hills area. That part chosen for the gas-storage project is where the basal conglomerate overlying the Franciscan schist is overlain by the nodular shale.

  18. Strontium isotope geochemistry of soil and playa deposits near Yucca Mountain, Nevada

    Energy Technology Data Exchange (ETDEWEB)

    Marshall, B.D.; Mahan, S.A.

    1994-12-31

    The isotopic composition of strontium contained in the carbonate fractions of soils provides an excellent tracer which can be used to test models for their origin. This paper reports data on surface coatings and cements, eolian sediments, playas and alluvial fan soils which help to constrain a model for formation of the extensive calcretes and fault infilling in the Yucca Mountain region. The playas contain carbonate with a wide range of strontium compositions; further work will be required to fully understand their possible contributions to the pedogenic carbonate system. Soils from an alluvial fan to the west of Yucca Mountain show that only small amounts of strontium are derived from weathering of silicate detritus. However, calcretes from a fan draining a carbonate terrane have strontium compositions dominated locally by the limestone strontium component. Although much evidence points to an eolian source for at least some of the strontium in the pedogenic carbonates near Yucca Mountain, an additional component or past variation of strontium composition in the eolian source is required to model the pedogenic carbonate system.

  19. Strontium isotope geochemistry of soil and playa deposits near Yucca Mountain, Nevada

    Energy Technology Data Exchange (ETDEWEB)

    Marshall, B.D.; Mahan, S.A.

    1994-12-31

    The isotopic composition of strontium contained in the carbonate fractions of soils provides an excellent tracer which can be used to test models for their origin. This paper reports data on surface coatings and cements, eolian sediments, playas and alluvial fan soils which help to constrain a model for formation of the extensive calcretes and fault infilling in the Yucca Mountain region. The playas contain carbonate with a wide range of strontium compositions; further work will be required to fully understand their possible contributions to the pedogenic carbonate system. Soils from an alluvial fan to the west of Yucca Mountain show that only small amounts of strontium are derived from weathering of silicate detritus. However, calcretes from a fan draining a carbonate terrane have strontium compositions dominated locally by the limestone strontium component. Although much evidence points to an eolian source for at least some of the strontium in the pedogenic carbonates near Yucca Mountain, an additional component or past variation of strontium composition in the eolian source is required to model the pedogenic carbonate system.

  20. Sostenibilidad sociocultural del turismo: propuestas para el cantón Playas. Provincia del Guayas, Ecuador

    Directory of Open Access Journals (Sweden)

    José Lázaro Quintero Santos

    2016-03-01

    Full Text Available Este artículo forma parte de la investigación “Propuesta de un Modelo de Desarrollo Turístico Sostenible para el cantón Playas, provincia del Guayas, Ecuador”. En este caso solo se hace referencia a la propuesta de un modelo de sostenibilidad sociocultural de los impactos del turismo. La investigación se realiza en el cantón Playas debido a la importancia estratégica que tiene el desarrollo del turismo para este territorio gracias a su efecto multiplicador en el resto de las actividades económicas. La metodología de la investigación ha incluido un estudio cuantitativo y cualitativo del territorio, así como, entrevistas y encuestas a los actores locales. Para lograr el objetivo de esta investigación se ha realizado un análisis social y cultural considerando los recursos patrimoniales y socioculturales de la zona. El estudio comprende programas y proyectos que permiten formular una propuesta de turismo sostenible que sea inclusiva y respetuosa con las comunidades y sus culturas.

  1. Ecología de la Taxocenosis de Peracaridos Macrobentónicos en Playas arenosas protegidas: Análisis Multiescala de los patrones Ecológicos y Consideraciones para su manejo Sustentable.

    OpenAIRE

    Torres Alfaro, Guadalupe Minerva

    2010-01-01

    Las playas arenosas son ambientes rigurosos donde los patrones comunitarios de macrofauna han sido relacionados con el tamaño de grano de arena, pendiente de la playa y procesos de ola/swash. Las relaciones entre la abundancia/diversidad de la macrofauna y morfodinámica de las playas micromareales de alta energía abiertas al mar dan pie a pensar un incremento de la abundancia/densidad desde playas con arena gruesa y fuerte pendiente hasta playas planas con arena fina y pendient...

  2. Calidad sanitaria de las aguas de playa en Costa Rica: comparación entre los períodos 1986 - 1987 y 1996 - 1997

    OpenAIRE

    Darner Mora Alvarado

    1998-01-01

    Se presenta una comparación de la calidad sanitaria de las aguas de 36 playas, ubicadas en ambos litorales durante los períodos 1986-1987 y 1996-1997. Para esto se utilizó la determinación de coliformes fecales/100 mL, y los parámetros físico-químicos de turbiedad y color, con una frecuencia de muestreo mensual y bimestral. Los resultados indican que existen cuatro aguas de playa que disminuyeron su contaminación fecal: Caldera, Quepos, Golfito y Cieneguita; por otro lado, 6 playas la increme...

  3. ESTRUCTURA POBLACIONAL DE DONAX STRIATUS (BIVALVIA, DONACIDAE EN PLAYA LAS BALSAS, GIBARA, CUBA

    Directory of Open Access Journals (Sweden)

    Frank A. Ocaña Borrego

    2011-06-01

    Full Text Available Donax striatus Linné 1767 es una de las dos especies de almejas de playa que se encuentra en el Caribe. Pocas investigaciones se han centrado en describir aspectos sobre la estructura poblacional de esta especie. Una población de D. striatus fue muestreada mensualmente desde febrero del 2008 hasta enero del 2009 en playa Las Balsas, Gibara, Cuba. La población mostró fluctuaciones estacionales de la densidad, presentando los mayores valores en los meses de mayo y octubre del 2008 y enero del 2009. Se encontraron tres picos de reclutamiento: abril-mayo, agosto del 2008 y enero del 2009. Se observó una distribución estratificada por grupos de tallas: los reclutas fueron registrados en los estratos superiores de la playa y los adultos, fundamentalmente, en los estratos bajos. La mayor abundancia se localizó en el estrato intermedio. No hubo correlación entre los cambios mensuales de densidad con las temperaturas, ni con las precipitaciones, sin embargo, parece que los cambios en el régimen habitual del oleaje y la elevación del nivel medio del mar tienen influencia sobre el comportamiento de la abundancia de esta especie. Se propone una hipótesis que combina parámetros morfodinámicos para explicar la distribución vertical de los diferentes componentes de la población. Donax striatus Linné 1767 is one of the two beach clam species that inhabits in the Caribbean. Few investigations have focused on describing aspects related with the population structure of this species. A population of D. striatus was surveyed from February 2008 to January 2009 in Las Balsas beach, Gibara, Cuba. The population showed seasonal fluctuations of the density presenting the higher values on May and October 2008 and January 2009. There were peaks of recruitment: April-May, August 2008 and January 2009. A stratified distribution by size classes was observed: recruits were found in the higher strata of the beach while adults occur mainly in the lowest strata

  4. Millennial-Scale Asian Monsoon Influenced Longjie Lake Evolution during Marine Isotope Stage 3, Upper Stream of Changjiang (Yangtze River, China

    Directory of Open Access Journals (Sweden)

    Chaozhu Li

    2015-01-01

    Full Text Available Millennial-scale climate change in Asian monsoon region during MIS 3 has been studied using stalagmite, loess, and peat sediments. However, records from more materials are essential to further illustrate dynamics of these events. In the present study, a time-series of grain size covering 60–30 ka was reconstructed from lake sediments in the Yunnan Province, southwestern China. The time-series contains 14 obvious millennial-scale events during the period. On millennial-scale, the grain size record is generally consistent with mean stalagmite δ18O from Hulu Cave, grain size of Gulang loess sequence, Chinese Loess Plateau, and Greenland ice core δ18O. The results show that the millennial-scale variation was well compared with the Dansgaard-Oeschger (DO events, indicating that those global events were well documented in lake sediments in the Asian monsoon region. Because the grain size can be used as a proxy for water discharge, we suggest that signal of the DO events might be transmitted to lake evolution by Asian monsoon.

  5. Community structure of the intertidal meiofauna along a gradient of morphodynamic sandy beach types in southern Chile Estructura comunitaria de la meiofauna intermareal en un gradiente de tipos morfodinámicos de playas arenosas en el sur de Chile

    Directory of Open Access Journals (Sweden)

    J. GERMÁN RODRÍGUEZ

    2001-12-01

    Full Text Available Three sandy beaches located in southern Chile (Gaviotas, Guabún and Mar Brava; ca. 42º S were studied during the summer of 2000 to analyse the patterns in abundance and biomass of the meiofauna along a gradient of morphodynamic beach types. Sediment samples were collected with metallic cylinders (23 cm² cross sectional area, 120 cm long at ten equally spaced tidal levels along six transects separated between 5 and 10 m and extending from above the drift line down to the low tide level. Porosity, shear strength, water content, penetrability and grain size of the substrate were measured in each sampling level. The meiofauna was primarily represented by Nematoda and Copepoda Harpacticoidea. The highest average density and biomass per unit of area were found at the reflective beach of Gaviotas (6,172 ind 10 cm-2 and 2.38 g m-2, ash free dry weight as compared with the intermediate beach of Guabún (3,390 ind 10 cm-2 and 1.70 g m-2 and the dissipative beach of Mar Brava (3,667 ind 10 cm-2 and 0.86 g m-2. Total abundance and biomass of the meiofauna per linear meter of beach (i.e., total meiofauna in an intertidal across-shore transect 1 m wide were higher at Mar Brava (506 x 10(6 ind m-1 and 119.4 g m-1, as compared with Gaviotas (271 x 10(6 ind m-1 and 101.7 g m-1 and Guabún (143 x 10(6 ind m-1 and 73.9 g m-1. Therefore, these last results show a trend of increasing intertidal meiofaunal abundances and biomass towards the dissipative stage of the beach gradient analyzed. The highest meiofaunal densities and biomass occurred at the upper and mid shore levels of each beach. Lower across-shore variability in density and biomass were found at the dissipative beach. Results of a Monte Carlo permutation test showed that water content, penetrability and grain size were the best predictor variables of meiofaunal density. Body sizes of nematodes, copepods, turbellarians, halacarids and ostracods were correlated with sediment characteristics. In general

  6. Epidemiological studies on dengue virus type 3 in Playa municipality, Havana, Cuba, 2001-2002.

    Science.gov (United States)

    Guzman, Maria G; Alvarez, Angel; Vazquez, Susana; Alvarez, Mayling; Rosario, Delfina; Pelaez, Otto; Cruz, Guillermo; Rodriguez, Rosmari; Pavon, Alequis; Gonzalez, Annia; Morier, Luis; Ruiz, Dydie; Kouri, Gustavo; Halstead, Scott B

    2012-03-01

    Recognizing the uniqueness of secondary dengue virus (DENV)-1/3 dengue hemorrhagic fever/dengue shock syndrome (DHF/DSS) cases at an interval of 24 years, we sought to estimate DENV infections as well as the ratios between mild disease and DHF/DSS by DENV infection sequence in Playa District (Havana, Cuba) during the 2001-2002 outbreak of dengue virus type 3 (DENV-3). A retrospective seroepidemiological study was conducted in 2003 in Playa District. Blood samples were collected from a 1% random sample of residents and were studied for the prevalence of dengue neutralizing antibodies. DENV-3 was found to have infected 7.2% (95% confidence interval (95% CI) 6.0-8.4%) of susceptible individuals (the entire cohort), the majority of whom experienced silent infections. Virtually every individual who had a secondary infection in the sequence DENV-1 then DENV-3 became ill, with a ratio of severe to mild cases of 1:35 (95% CI 1:67-1:23). Secondary infections in the sequence DENV-2/3 were less pathogenic than DENV-1/3. Mild disease accompanying secondary DENV2/3 occurred at a ratio of 1:4.49 infections (95% CI 1:5.77-1:3.42) secondary infections. The results obtained highlight the role of the infecting serotype and also the sequence of the viral infection in the clinical outcome of a dengue infection. Copyright © 2011 International Society for Infectious Diseases. Published by Elsevier Ltd. All rights reserved.

  7. Mapping playa evaporite minerals with AVIRIS data: A first report from death valley, California

    Science.gov (United States)

    Crowley, J.K.

    1993-01-01

    Efflorescent salt crusts in Death Valley, California, were mapped by using Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) data and a recently developed least-squares spectral band-fitting algorithm. Eight different saline minerals were remotely identified, including three borates, hydroboracite, pinnoite, and rivadavite, that have not been previously reported from the Death Valley efflorescent crusts. The three borates are locally important phases in the crusts, and at least one of the minerals, rivadavite, appears to be forming directly from brine. Borates and other evaporite minerals provide a basis for making remote chemical measurements of desert hydrologic systems. For example, in the Eagle Borax Spring area, the AVIRIS mineral maps pointed to elevated magnesium and boron levels in the ground waters, and to the action of chemical divides causing subsurface fractionation of calcium. Many other chemical aspects of playa brines should have an expression in the associated evaporite assemblages. Certain anhydrous evaporites, including anhydrite, glauberite, and thenardite, lack absorption bands in the visible and near-infrared wavelength range, and crusts composed of these minerals could not be characterized by using AVIRIS. In these situations, thermal-infrared remote sensing data may complement visible and near-infrared data for mapping evaporites. Another problem occurred in wet areas of Death Valley, where water absorption caused low signal levels in the 2.0-2.5 ??m wavelength region that obscured any spectral features of evaporite minerals. Despite these difficulties, the results of this study demonstrate the potential for using AVIRIS and other imaging spectrometer data to study playa chemistry. Such data can be useful for understanding chemical linkages between evaporites and ground waters, and will facilitate studies of how desert ground-water regimes change through time in response to climatic and other variables. ?? 1993.

  8. Extending the record of lacustrine phases beyond the last interglacial for Lake Eyre in central Australia using luminescence dating

    Science.gov (United States)

    Fu, Xiao; Cohen, Tim J.; Arnold, Lee J.

    2017-04-01

    We show with multiple luminescence dating techniques that the sedimentary record for Lake Eyre, Australia's largest lake, extends beyond 200 thousand years (ka) to Marine Isotope Stage (MIS) 7. Transgressive clayey sand and finely laminated clays overlying the Miocene Etadunna Formation in Lake Eyre North document the deep-lake phases of central South Australia in the past. Until now, unresolved chronology has hampered our ability to interpret these sedimentary records, which are important for understanding the timing of the wettest phase of central Australia's late Quaternary climate. In this study, we apply quartz optically stimulated luminescence (OSL) dating, thermally-transferred OSL (TT-OSL) dating and K-feldspar post infrared infrared stimulated luminescence (pIRIR) dating to lake-floor sediments near Williams Point in Madigan Gulf to provide new age constraint for the lacustrine sediments of Lake Eyre. Methodological studies on quartz and K-feldspar demonstrate that these luminescence dating procedures are suitable for the Lake Eyre lacustrine samples and produce consistent replicate ages. A Bayesian model applied to the new dating results provides a chronological model of lacustrine deposition and shows that the transgressive clayey sand were deposited 221 ± 19 ka to 201 ± 10 ka and that the deep-water sediments were laid down in early MIS 6 (191 ± 9 ka to 181 ± 9 ka). We also find evidence for a potential depositional hiatus in mid MIS 6 and the likely formation of a palaeo-playa later in MIS 6 from 158 ± 11 ka to 143 ± 15 ka. In contrast, the MIS 5 sediments are characterised by oscillating deep- and shallow-water lacustrine units deposited 130 ± 16 ka to 113 ± 20 ka. This study is the first of its kind to provide evidence for a wet desert interior in Australia beyond the last glacial cycle using comprehensive numerical dating. Our results show that past deep-lake episodes of central South Australia, which were previously thought to represent

  9. Titan in a Fume Hood: Room-Temperature Simulation of a Titan Evaporite Playa Using a Multi-Component Mixture of Organic Compounds

    Science.gov (United States)

    Malaska, M.; Radebaugh, J.; Barnes, J.; Mitchell, K.

    2012-03-01

    A multi-component mixture of organic compounds in heptanes was evaporated to simulate the formation of an evaporite playa on Titan. The deposition sequence of the analog materials and their implications for Titan geology will be presented.

  10. Calidad sanitaria de las aguas de playa en Costa Rica: comparación entre los períodos 1986 - 1987 y 1996 - 1997

    Directory of Open Access Journals (Sweden)

    Darner Mora Alvarado

    1998-12-01

    Full Text Available Se presenta una comparación de la calidad sanitaria de las aguas de 36 playas, ubicadas en ambos litorales durante los períodos 1986-1987 y 1996-1997. Para esto se utilizó la determinación de coliformes fecales/100 mL, y los parámetros físico-químicos de turbiedad y color, con una frecuencia de muestreo mensual y bimestral. Los resultados indican que existen cuatro aguas de playa que disminuyeron su contaminación fecal: Caldera, Quepos, Golfito y Cieneguita; por otro lado, 6 playas la incrementaron: Doña Ana, Azul, Mantas, Jacó, Puerto Jiménez y Balneario Municipal de Limón. Las restantes 26 playas se mantuvieron sin una contaminación fecal importante. Las playas no aptas para la natación son: Azul, Quepos, Guacalillo (sólo tiene datos del 96-97, Balneario Municipal y Cieneguita. Por último, se determinó que las principales fuentes de contaminación terrestre son las descargas de aguas domésticas sin tratamiento al mar, ríos, quebradas y esteros que desembocan en las cercanías de la playa.

  11. Lake Cadagno

    DEFF Research Database (Denmark)

    Tonolla, Mauro; Storelli, Nicola; Danza, Francesco

    2017-01-01

    Lake Cadagno (26 ha) is a crenogenic meromictic lake located in the Swiss Alps at 1921 m asl with a maximum depth of 21 m. The presence of crystalline rocks and a dolomite vein rich in gypsum in the catchment area makes the lake a typical “sulphuretum ” dominated by coupled carbon and sulphur cyc...

  12. LIMNOLOGY, LAKE BASINS, LAKE WATERS

    Directory of Open Access Journals (Sweden)

    Petre GÂŞTESCU

    2009-06-01

    Full Text Available Limnology is a border discipline between geography, hydrology and biology, and is also closely connected with other sciences, from it borrows research methods. Physical limnology (the geography of lakes, studies lake biotopes, and biological limnology (the biology of lakes, studies lake biocoenoses. The father of limnology is the Swiss scientist F.A. Forel, the author of a three-volume entitled Le Leman: monographie limnologique (1892-1904, which focuses on the geology physics, chemistry and biology of lakes. He was also author of the first textbook of limnology, Handbuch der Seenkunde: allgemeine Limnologie,(1901. Since both the lake biotope and its biohydrocoenosis make up a single whole, the lake and lakes, respectively, represent the most typical systems in nature. They could be called limnosystems (lacustrine ecosystems, a microcosm in itself, as the American biologist St.A. Forbes put it (1887.

  13. EL IMPACTO DE LA AGRICULTURA INTENSIVA EN EL USO TURÍSTICO DE LAS PLAYAS DE MARINA DE COPE (MURCIA

    Directory of Open Access Journals (Sweden)

    F. Belmonte Serrato

    2011-01-01

    Full Text Available El desarrollo de la agricultura intensiva y, especialmente, la ocupación agrícola de los fondos de las ramblas, ha ocasionado un desequilibrio sedimentario en las playas de Marina de COPE. Los retrocesos de la línea de costa oscilan entre 16 y 68 m y la disminución de la superficie se estima en un 50% de la correspondiente a 1956. Esto, ha reducido su capacidad de carga potencial que, para una intensidad de uso de 25 m2/usuario, ha pasado de 4.400 usuarios potenciales por día a 2.200. Lo que implica, para los meses de uso de estas playas, julio y agosto, una pérdida de capacidad de 130.000 usuarios.

  14. Distribución espacial de Ocypode quadrata (Decapoda: Ocypodidae en ocho playas de la zona norte oriental de Cuba

    Directory of Open Access Journals (Sweden)

    Frank A. Ocaña

    2012-09-01

    Full Text Available Uno de los organismos más comunes en las playas arenosas son los miembros del género Ocypode conocidos como cangrejos fantasmas, están ampliamente distribuidos en las regiones tropicales y subtropicales; además tienen un importante papel en la transferencia de energía en diferentes niveles tróficos. El objetivo del presente trabajo es dar a conocer aspectos relacionados con la variación espacial de la densidad de O. quadrata en playas con diferente nivel de influencia humana en la costa norte oriental de Cuba. En mayo de 2010, fueron contadas un total de 355 galerías en 360 unidades de muestreo. La composición por clases de tallas fue de 237 galerías de jóvenes y 118 de adultos. Del total de galerías contadas el 74% ocuparon el nivel P1, 20% el nivel P2 y 6% el nivel P3. La densidad varió entre 0.06-0.52galerías/m2. A pesar del nivel de influencia humana, la mayoría de las playas no mostró diferencias significativas en la densidad de galerías (Scheffé, p>0.05. La densidad de individuos en la zona superior de resaca del oleaje es mayor (Scheffé, p<0.05, predominando los jóvenes y en el resto de los estratos la densidad total va disminuyendo y predominan los individuos adultos. El patrón de variación entre los estratos no fue el mismo para todas las playas. En el presente estudio no se encontró evidencia directa entre el nivel de turismo y la densidad de galerías del cangrejo fantasma

  15. Variación espacio-temporal de la meiofauna submareal en una playa arenosa nororiental de Venezuela

    Directory of Open Access Journals (Sweden)

    Ildefonso Liñero Arana

    2013-03-01

    Full Text Available La meiofauna incluye metazoos y foraminíferos bénticos que pasan a través de un tamiz de 500mm y son retenidos en malla de 40-63μm. Se estudió la variación espacial y temporal de la meiofauna en cuatro estaciones submareales a 1m de profundidad, de una playa arenosa situada en la costa nororiental de Venezuela. Mensualmente, durante un año, en cada estación, con un nucleador de 2.5cm de diámetro interno, se tomaron tres réplicas de sedimento hasta 10cm de profundidad y se pasaron a través de un tamiz de 0.063mm de abertura de malla. Se identificaron 14 grupos meiofaunales, excluidos los foraminíferos, siendo los nemátodos, ostrácodos y copépodos harpacticoides los más abundantes. La densidad mensual estuvo comprendida entre 64 y 503ind./10cm², y la densidad media en las estaciones entre 173 y 449ind./10cm². La densidad de la meiofauna en la playa San Luis es baja en comparación con otros estudios realizados en zonas tropicales. En esta playa el control de las comunidades meiofaunísticas es compartido por las condiciones climáticas y la biología de las especies.

  16. Biología pesquera de la langosta Panulirus gracilis en Playa Lagarto, Guanacaste, Costa Rica

    Directory of Open Access Journals (Sweden)

    Helven Naranjo Madrigal

    2011-06-01

    Full Text Available Los parámetros biológicos y pesqueros analizados se fundamentaron en una muestra de 843 langostas provenientes de la actividad pesquera realizada en Playa Lagarto entre noviembre del 2007 y octubre del 2008. Las longitudes cefalotoráxicas de los machos estuvo comprendida entre los 143.6 y 42.8 y 115 y 35.8mm para hembras. El 74.9% de las langostas en los desembarques estuvo por debajo de la talla mínima legal de captura (80 mm de LC. La estructura de tallas muestra un considerable solapamiento de segmentos poblacionales y el incremento de las tallas con la profundidad en donde operan las dos modalidades de pesca estudiadas: el buceo a pulmón y el buceo con compresor. La proporción de sexos obtenida fue de 1.36 M:H. La relación entre LC y peso reveló que las hembras pesan más que los machos de una misma talla y que esta diferencia fue significativa (pBiology and fishery of the lobster Panulirus gracilis in Playa Lagarto, Guanacaste, Costa Rica. Panulirus gracilis is a high valuable lobster species with considerable captures along the tropical Pacific coast. In this study, I present some biological and fishery parameters described after a sample of 843 lobsters, landed in Playa Lagarto from November 2007 to October 2008. From landing records, a total of 74.9% of lobsters were below the minimum legal catch size (80mm CL. Carapace lengths were in the range of 42.8 and 143.6mm for males and 115 and 35.8mm for females. The size structure showed a wide overlapping of population segments, and a trend to increase with depth, where lung diving and “hooka” diving operations take place. Sex ratio was 1.36 M:H. The relationship between weight and LC revealed that females are heavier than males of the same size, and this difference was significant (p<0.05. The von Bertalanffy growth parameters for males and females respectively (K=0.45-0.38, LC∞=166.9-121.7 showed accelerated growth compared to other species. Males observed a higher growth rate

  17. Sedimentología y morfología de la playa de anidación para tortugas marinas, El Carrizal, Coyuca de Benítez, Guerrero

    OpenAIRE

    2010-01-01

    De agosto del 2007 a junio del 2009, se llevaron a cabo 10 perfiles topográficos en playa Carrizal durante las épocas de lluvias y estiaje de estos años para determinar el cambio morfológico de la playa. Paralelamente se realizó un muestreo de sedimentos en la infraplaya, mesoplaya y supraplaya asociados con estos perfiles de playa. Los resultados muestran los mayores cambios morfológicos de la playa en la zona aledaña a la boca de la laguna de Coyuca con escalones de erosión en las bermas de...

  18. A Holocene Sediment Record From Lake Elsinore, Southern California: Evidence for Relative Lake Level Change and the Onset of ENSO.

    Science.gov (United States)

    Kirby, M. E.; Lund, S. P.; Poulsen, C. J.

    2003-12-01

    There are very few complete terrestrial, Holocene paleoclimate records from coastal southwestern North America. Lake Elsinore, located 120km southeast of Los Angeles, represents one of the only natural, non-playa lakes in the region. Furthermore, it is well documented that coastal southwestern North America is highly sensitive to changes in atmospheric circulation and its affect on regional hydrodynamics. As shown by Kirby et al. (in press), modern lake levels at Lake Elsinore respond directly to total annual precipitation, particularly winter season amounts. The lake is also located along the eastern Pacific Ocean where changes in ocean circulation and its thermal structure modulate the overlying atmosphere, and thus the adjacent continental climate. Here, we present two 7 meter sediment core records from Lake Elsinore spanning the entire Holocene. Although the cores are from the lake's littoral zone, they show surprisingly complete records with very little lithologic evidence for major hiatuses. A combination of sedimentological analyses (e.g., mass magnetic susceptibility (CHI); total percent carbonate; total organic matter) and lithologic descriptions provide insight to lake dynamics over the Holocene. Using the historical calibration between magnetic susceptibility and relative lake level (i.e., high lake levels = high CHI values and vice versa) from Kirby et al. (in press), we developed a first-order estimate of Holocene relative lake levels for Lake Elsinore. The historic calibration is extrapolated through the sediment record based on the assumption that, like today, first order lake level change is directly related to precipitation amount. Both total percent carbonate and total organic matter support our historical calibration between CHI and lake level. Our data suggest a relative increase in lake levels during the mid-Holocene (ca. 8,000 cal yr BP) and through to the present day. From this observation, we hypothesize that regional hydrology as linked to

  19. District wide water resources investigation and management using LANDSAT data. Phase 1: Lake volume

    Science.gov (United States)

    Shih, S. F. (Principal Investigator)

    1982-01-01

    A technique for estimating available water storage volume using LANDSAT data was developed and applied to Lake Washington and Lake Harris in central Florida. The technique can be applied two ways. First, where the historical stage records are available, the historical LANDSAT data can be used to establish the relationship between lake volume and lake stage. In the second case, where the historical stage records are not available, the historical LANDSAT data can be used to estimate the historical lake stage after the lake volume and stage information become available in the future.

  20. Feeding competition between larval lake whitefish and lake herring

    Science.gov (United States)

    Savino, Jacqueline F.; Hudson, Patrick L.

    1995-01-01

    The potential for competition for food between larval lake whitefish (Coregonus clupeaformis) and lake herring (C. artedi) 1- to 8-wk of age was explored in a series of 1-h laboratory feeding studies. Feeding started at 2-wk post-hatch. Learning and fish size appear to be more important than prey density at the onset of feeding. Species differed in their feeding behavior and consumption noticeably by 5-wk and substantially by 8-wk. Lake whitefish generally were more aggressive foragers than lake herring, attacking and capturing more prey. At high plankton density at 8-wk, lake herring feeding was depressed in mixed-fish treatments. This difference in competitive food consumption between the two coregonids occurs at a critical life stage, and when combined with other biotic and abiotic factors, may have a significant impact on recruitment.

  1. Eolian deposition cycles since AD 500 in Playa San Bartolo lunette dune, Sonora, Mexico: Paleoclimatic implications

    Science.gov (United States)

    Ortega, Beatriz; Schaaf, Peter; Murray, Andrew; Caballero, Margarita; Lozano, Socorro; Ramirez, Angel

    2013-12-01

    Records of past climatic changes in desert environments are scarce due to the poor preservation of biological proxies. To overcome this lack we consider the paleoenvironmental significance and age of a lunette dune at the eastern rim of Playa San Bartolo (PSB) in the Sonoran Desert (Mexico). Thermoluminescence and optical stimulated luminescence (TL and OSL) provide the chronology of lunette dune development. Mineralogical, geochemical (major, trace and REE element concentrations) and rock magnetic analyses allow for the assessment of sediment provenance and changes in the composition of the PSB dune over time. The upper 6 m of dune accumulation occurred over the past 1.5 ka, largely during AD 500-1200, a period that correlates with the Medieval climatic anomaly (AD 300-1300). Variability in composition of dune sediments is attributed to changes in sediment sources. Sand sized deposits are mainly eroded from granitoids from nearby outcrops. Sandy silt deposits, rich in evaporative minerals, resulted after the flooding of PSB, later deflation and accumulation of both detritic and authigenic components in the dune. These findings suggest that main dune accretion occurred during regionally extended drought conditions, disrupted by sporadic heavy rainfall.

  2. Determinantes de competitividad turística en destinos de sol y playa mexicanos

    Directory of Open Access Journals (Sweden)

    Carlos Mario Amaya Molinar

    2017-01-01

    Full Text Available El estudio se orienta a determinar si los agentes de riesgo, como la población residente y los visitantes, pueden percibir los factores de la competitividad de los destinos turísticos. Para lograr dicho objetivo se revisó el estado del arte de la literatura académica sobre el tema, se identificaron los modelos teóricos más reconocidos y las variables e indicadores utilizados con más frecuencia. El estudio empírico, realizado en dos destinos mexicanos de sol y playa, sugiere que los agentes de riesgo pueden percibir algunos de esos factores. Y aunque sólo se empleó un muestreo de conveniencia, en investigaciones futuras se podría utilizar uno probabilístico. Este trabajo contribuye a profundizar en la comprensión de los factores que determinan la competitividad de los destinos turísticos, y trasciende el empleo de índices nacionales abstractos o estudios descriptivos.

  3. [Biology and fishery of the lobster Panulirus gracilis in Playa Lagarto, Guanacaste, Costa Rica].

    Science.gov (United States)

    Madrigal, Helven Naranjo

    2011-06-01

    Panulirus gracilis is a high valuable lobster species with considerable captures along the tropical Pacific coast. In this study, I present some biological and fishery parameters described after a sample of 843 lobsters, landed in Playa Lagarto from November 2007 to October 2008. From landing records, a total of 74.9% of lobsters were below the minimum legal catch size (80 mm CL). Carapace lengths were in the range of 42.8 and 143.6 mm for males and 115 and 35.8 mm for females. The size structure showed a wide overlapping of population segments, and a trend to increase with depth, where lung diving and "hooka" diving operations take place. Sex ratio was 1.36 M:H. The relationship between weight and LC revealed that females are heavier than males of the same size, and this difference was significant (p fishing mortality (F) was higher in males (0.49-2.34-1.92) than in females (0.47-1.82-1.42). Recruitment was continuous for both sexes during the year, with an elevated intensity of 18.5% in July. Under the current fishing regime the population could be at risk of collapse, as indicated by the high exploitation rate (E) 0.80

  4. Casa de campo en la playa de Jávea, Valencia – España

    Directory of Open Access Journals (Sweden)

    De Jorge, M.

    1971-03-01

    Full Text Available This house is adapted to a gentle pine covered slope, extending down to the beach. There is a number of stepped down bedrooms, following the ground contour. The main bedroom is at the top, and it is on the same level as the dining and living room, the kitchen and other services, and two terraces facing north and south. At the lower part of the building there is a music and study room, with an independent entrance and a covered porch, for winter use. There is also a basement, firewood store room and other secondary rooms, which can allow for future extensions.El acoplamiento a una suave ladera cubierta de pinos, que desciende hacia la playa, determina una serie de dormitorios escalonados, según la pendiente del terreno, que culminan en la parte superior de la vivienda con el dormitorio principal, situado ya en el mismo plano que el salón-comedor, las terrazas principales N. y S. y la cocina y servicios anexos. En la parte inferior se sitúa un estudio-sala de música, con entrada independiente y un porche cubierto para invierno, junto con la bodega, leñera y otros servicios y espacios previstos para una posible ampliación.

  5. Eolian sand deposition during th Medieval Climatic Anomaly in Playa San Bartolo, Sonora, Mexico

    Science.gov (United States)

    Ortega, B.; Schaaf, P. E.; Murray, A.; Caballero, M.; Lozano Garcia, S.; Ramirez, A.

    2012-12-01

    Records of past climatic changes in desert environments are scarce due to the poor preservation of biological proxies. To overcome this lack we consider the paleoenvironmental significance and age of a lunette dune in the eastern rim of the Playa San Bartolo (PSB) in Sonoran Desert (Mexico). Rock magnetism, mineralogical, and geochemical analysis (major, trace and REE) allow assessment of sediment provenance and changes in the composition of the PSB dune over time. Thermoluminiscence and optical stimulated luminescence (TL and OSL) provide the chronology of lunette dune development. Dune sediments are composed by intercalated layers of sand beds and sandy silt strata. Variability in composition of dune sediments is attributed to changes in sediment sources. Mineralogical, geochemical and magnetic data show clear differences between the sand and the sandy silt of the PSB dune deposits, which suggest different sediment sources. Sand sized deposits, characterized by coarse magnetite grains, are mainly eroded from granitoids from nearby outcrops. Sandy silt deposits, rich in fine grained magnetite and evaporative minerals, resulted after the erosion of volcanic rocks and their soils from sierras at the NE of PSB during heavy rainfall episodes, the flooding of PSB and later deflation and accumulation in the dune of both detritic and authigenic components. The upper 6 m of dune accumulation occurred largely during AD 500 to 1200, a period that correlates with the Medieval climatic anomaly (AD 300 to 1300). These findings suggest that main dune accretion occurred during regionally extended drought conditions, disrupted by sporadic heavy rainfall.

  6. Tipos de tiempo para el turismo de sol y playa en el litoral alicantino

    Directory of Open Access Journals (Sweden)

    Martínez Ibarra, Emilio

    2008-06-01

    Full Text Available In this article the author proposes a series of weather types, with the purpose of evaluating the climatic-tourist potencial for the tourism of sun and beach in the coast of Alicante. The method, analysis of the frequency of the density of use of the practice the suntan and swin, the type of consulted source (webcam images, as well as the diversity of distinguished types, make of this work a novel contribution, in a branch of the knowledge relatively little cultivated although emergent: the Tourist Climatology.

    En el presente trabajo se proponen una serie de tipos de tiempo, con la finalidad de evaluar el potencial climático-turístico para el turismo de sol y playa en el litoral alicantino. El método, análisis de la frecuentación de la densidad de uso de la práctica del bronceado y baño, el medio a partir del cual se ha obtenido la información (imágenes webcam, así como la diversidad de tipos distinguidos, hacen de este trabajo una aportación novedosa, en una rama del conocimiento relativamente poco cultivada aunque emergente: la Climatología Turística.

  7. Hydrology of Hunters Lake, Hernando County, Florida

    Science.gov (United States)

    Henderson, S.E.

    1986-01-01

    The size and shape of Hunters Lake, Florida has been significantly altered by development of the surrounding Spring Hill residential community. The lake is the largest in Hernando County, enlarged by lakeshore excavation and connection to nearby ponds to an area of 360 acres at an average stage of 17.2 ft above sea level. Hunters Lake is naturally a closed lake, but development of Spring Hill has resulted in a surface water outflow from the lake in its southwest corner. Inflow to the lake could occur on the east side during extreme high-water periods. The karst terrain of the Hunters Lake area is internally drained through permeable soils, depressions, and sinkholes, and natural surface drainage is absent. The underlying Floridan aquifer system is unconfined except locally near coastal springs. Flow in the groundwater system is to the west regionally and to the southwest in the immediate area of Hunters Lake. Water level gradients in the groundwater system increase from 1.4 ft/mi east of the lake to about 8 ft/mi southwest of the lake. Hunters Lake is hydraulically connected to the groundwater system, receiving groundwater on the northeast side and losing water to the groundwater system on the southwest side. This close relationship with the groundwater system is demonstrated by graphical and numerical comparison of Hunters Lake stage with water levels in nearby groundwater sites. During 1965-84, the stage of Hunters Lake fluctuated between 12.48 and 20.7 ft above sea level. Because area lakes are all directly affected by groundwater levels, they also show a close relationship with water levels in Hunters Lake. Analysis of water quality data for Hunters Lake indicates that the water of the lake is a soft calcium bicarbonate type with ionic concentrations higher than in water from nearby shallow wells and lower than in water from the Upper Floridan aquifer. Samples collected in 1981-1983 indicate slightly higher levels of ionic concentration than in 1965

  8. Great Salt Lake, and precursors, Utah: The last 30,000 years

    Science.gov (United States)

    Spencer, R.J.; Baedecker, M.J.; Eugster, H.P.; Forester, R.M.; Goldhaber, M.B.; Jones, B.F.; Kelts, K.; McKenzie, J.; Madsen, D.B.; Rettig, S.L.; Rubin, M.; Bowser, C.J.

    1984-01-01

    Sediment cores up to 6.5 m in length from the South Arm of Great Salt Lake, Utah, have been correlated. Radiocarbon ages and volcanic tephra layers indicate a record of greater than 30,000 years. A variety of approaches have been employed to collect data used in stratigraphic correlation and lake elevation interpretation; these include acoustic stratigraphy, sedimentologic analyses, mineralogy, geochemistry (major element, C, O and S isotopes, and organics), paleontology and pollen. The results indicate that prior to 32,000 year B.P. an ephemeral saline lake-playa system was present in the basin. The perennial lake, which has occupied the basin since this time, rose in a series of three major steps; the freshest water conditions and presumably highest altitude was reached at about 17,000 year B.P. The lake remained fresh for a brief period, followed by a rapid increase in salinity and sharp lowering in elevation to levels below that of the present Great Salt Lake. The lake remained at low elevations, and divided at times into a north and south Basin, until about 8,000 year B.P. Since that time, with the exception of two short rises to about 1290 m, the lake level has remained near the present elevation of 1280 m. ?? 1984 Springer-Verlag.

  9. Embryotoxicity of an extract from Great Lakes lake trout to rainbow trout and lake trout

    Energy Technology Data Exchange (ETDEWEB)

    Wright, P.J.; Tillitt, D.E. [National Biological Service, Columbia, MO (United States). Midwest Science Center

    1995-12-31

    Aquatic ecosystems such as the Great Lakes are known to be contaminated with chemicals that are toxic to fish. However, the role of these contaminants in reproductive failures of fishes, such as lake trout recruitment, has remained controvertible. It was the objective to evaluate dioxin-like embryotoxicity of a complex mixture of chemicals and predict their potential to cause the lack of recruitment in Great Lakes lake trout. Graded doses of a complex environmental extract were injected into eggs of both rainbow trout and lake trout. The extract was obtained from whole adult lake trout collected from Lake Michigan in 1988. The extract was embryotoxic in rainbow trout, with LD50 values for Arlee strain and Erwin strain of 33 eggEQ and 14 eggEQ respectively. The LOAEL for hemorrhaging, yolk-sac edema, and craniofacial deformities in rainbow trout were 2, 2, and 4 eggEQ, respectively. Subsequent injections of the extract into lake trout eggs were likewise embryotoxic, with an LD50 value of 7 eggEQ. The LOAEL values for the extract in lake trout for hemorrhaging, yolk-sac edema, and craniofacial deformities were 0.1, 1, and 2 eggEQ, respectively. The current levels of contaminants in lake trout eggs are above the threshold for hemorrhaging and yolk-sac edema. The results also support the use of an additive model of toxicity to quantify PCDDs, PCDFs, Non-o-PCBs, and Mono-o-PCBs in relation to early life stage mortality in Lake Michigan lake trout.

  10. La patrimonialización de un paisaje marítimo: de la arena de la playa a la arena política

    Directory of Open Access Journals (Sweden)

    Eliseu Carbonell

    2010-01-01

    Full Text Available En este artículo exploramos los significados y usos sociales que tiene la playa en una población de la costa central catalana. Consideramos de forma especial los procesos de patrimonialización que se están llevando a cabo en esta playa por parte de una asociación de amantes de la navegación tradicional, proceso que está afectando a otros usuarios de la playa. El conflicto vivido a raíz de la oposición ciudadana a un proyecto de rehabilitación del frente marítimo pone de relieve que la playa es considerada patrimonio en sí misma e incide de lleno en los discursos y representaciones de la identidad local. El proceso de patrimonialización de la playa se verá inmiscuido en las dinámicas de inclusión/exclusión como sujeto y objeto.

  11. Tapped lakes as sediment traps in an Arctic delta

    Science.gov (United States)

    Walker, J.; McGraw, M.

    2015-03-01

    Lakes within the Colville River delta in northern Alaska, USA, vary in size from small ponds created by ice-wedge growth to thaw lakes that are as much as three kilometres long and ten metres deep. As the river migrates, lake edges are breached and the lakes are drained. Such lake tapping is aided by permafrost thaw and ice wedge melt and, in the case of the larger lakes, by wave action within them. Once a lake is tapped, it drains rapidly creating a deep scour hole at its entrance and from then on it is subject to the varying stages and discharge of the river. During flooding, when the river is transporting its largest amount of sediment, the tapped lakes become settling basins and rapidly fill. The Colville River delta has lakes in all stages from freshly breached to those that are now being destroyed by channel migration.

  12. Record of glacial Lake Missoula floods in glacial Lake Columbia, Washington

    Science.gov (United States)

    Hanson, Michelle A.; Clague, John J.

    2016-02-01

    During the last glaciation (marine oxygen isotope stage 2), outburst floods from glacial Lake Missoula deposited diagnostic sediments within glacial Lake Columbia. Two dominant outburst flood lithofacies are present within glacial Lake Columbia deposits: a flood expansion bar facies and a finer-grained hyperpycnite facies. We conclude that the flood sediments have a glacial Lake Missoula source because: (1) current indicators indicate westward flow through the lake, and upvalley flow followed by downvalley flow in tributary valleys; (2) no flood sediments are found north of a certain point; (3) there is a dominance of Belt-Purcell Supergroup clasts in a flood expansion bar; and (4) some of the finer-grained beds have a pink colour, reflective of glacial Lake Missoula lake-bottom sediments. A new radiocarbon age of 13,400 ± 100 14C BP on plant detritus found below 37 flood beds helps constrain the timing of outburst flooding from glacial Lake Missoula.

  13. Toxicity of smelter slag-contaminated sediments from Upper Lake Roosevelt and associated metals to early life stage White Sturgeon (Acipenser transmontanus Richardson, 1836)

    Science.gov (United States)

    Little, E.E.; Calfee, R.D.; Linder, G.

    2014-01-01

    The toxicity of five smelter slag-contaminated sediments from the upper Columbia River and metals associated with those slags (cadmium, copper, zinc) was evaluated in 96-h exposures of White Sturgeon (Acipenser transmontanus Richardson, 1836) at 8 and 30 days post-hatch. Leachates prepared from slag-contaminated sediments were evaluated for toxicity. Leachates yielded a maximum aqueous copper concentration of 11.8 μg L−1 observed in sediment collected at Dead Man's Eddy (DME), the sampling site nearest the smelter. All leachates were nonlethal to sturgeon that were 8 day post-hatch (dph), but leachates from three of the five sediments were toxic to fish that were 30 dph, suggesting that the latter life stage is highly vulnerable to metals exposure. Fish maintained consistent and prolonged contact with sediments and did not avoid contaminated sediments when provided a choice between contaminated and uncontaminated sediments. White Sturgeon also failed to avoid aqueous copper (1.5–20 μg L−1). In water-only 96-h exposures of 35 dph sturgeon with the three metals, similar toxicity was observed during exposure to water spiked with copper alone and in combination with cadmium and zinc. Cadmium ranging from 3.2 to 41 μg L−1 or zinc ranging from 21 to 275 μg L−1 was not lethal, but induced adverse behavioral changes including a loss of equilibrium. These results suggest that metals associated with smelter slags may pose an increased exposure risk to early life stage sturgeon if fish occupy areas contaminated by slags.

  14. Effects of sediment removal on vegetation communities in Rainwater Basin playa wetlands.

    Science.gov (United States)

    Beas, Benjamin J; Smith, Loren M; LaGrange, Theodore G; Stutheit, Randy

    2013-10-15

    Sedimentation from cultivated agricultural land use has altered the natural hydrologic regimes of depressional wetlands in the Great Plains. These alterations can negatively affect native wetland plant communities. Our objective was to determine if restored wetlands are developing plant communities similar to reference wetland conditions following hydrologic restoration. For this study, hydrology was restored via sediment removal. Thirty-four playa wetlands in reference, restored, and agricultural condition within the Rainwater Basin Region of Nebraska were sampled in 2008 and 2009. In 2008, reference and restored wetlands had higher species richness and more native, annual, and perennial species than agricultural wetlands. Restored wetlands had similar exotic species richness compared to reference and agricultural wetlands; however, reference wetlands contained more than agricultural wetlands. Restored wetlands proportion of exotics was 3.5 and 2 times less than agricultural wetlands and reference wetlands respectively. In 2009, reference and restored wetlands had higher species richness, more perennial species, and more native species than agricultural wetlands. Restored wetlands contained a greater number and proportion of annuals than reference and agricultural wetlands. Canonical Correspondence Analysis showed that reference, restored, and agricultural wetlands are dominated by different plant species and guilds. Restored wetland plant communities do not appear to be acting as intermediates between reference and agricultural wetland conditions or on a trajectory to reach reference conditions. This may be attributed to differing seed bank communities between reference and restored wetlands, dispersal limitations of perennial plant guilds associated with reference wetland conditions, and/or management activities may be preventing restored wetlands from reaching reference status. Copyright © 2013 Elsevier Ltd. All rights reserved.

  15. Contribución de la arquitectura efímera para un equipamiento costero en Playa de Patos

    OpenAIRE

    Visier Navarro, Gustavo

    2014-01-01

    La disertación de proyecto de este trabajo pesquisa una solución adaptativa de la “arquitectura efímera” para ser aplicada en el proyecto de un Equipamiento Deportivo Costero, cuya función se determina como escuela de surf en la Playa de Patos, Ayuntamiento de Nigrán, al sur de Galicia, España. El ámbito de actuación está clasificado como suelo rústico especialmente protegido (S.R.E.P.) de protección de costas, lo cual restringe la construcción en esta zona de cualquier estr...

  16. Inseguridad y Crisis Económica en el Imaginario Social de Playas de Rosarito, Baja California

    OpenAIRE

    Jesús Angel Enríquez Acosta; Alejandra Meza; Noelia Fierro

    2015-01-01

    Este trabajo ofrece un análisis acerca de como los habitantes de Playas de Rosarito en Baja California, imaginan y perciben el impacto de la crisis económica norteamericana mas reciente y la inseguridad mexicana en la actividad turística, principal vocación económica del lugar. Los testimonios de los habitantes expresan la transformación social, urbana y cultural del lugar turístico y de los problemas asociados a ciudades en rápido crecimiento. Se trata de una ciudad fronteriza con Estados Un...

  17. Compuestos del ciclo del carbono en la zona litoral del municipio Playa, Ciudad de la Habana, Cuba.

    OpenAIRE

    Montalvo, J. F.; García, I.; Esponda, S.C.; Cesar, M.E.; Alburquerque, O.

    2009-01-01

    Se realizaron cinco muestreos entre enero de 2007 y junio de 2008 a la zona costera del municipio Playa, con el fin de evaluar los contenidos de los compuestos del ciclo del carbono. Los parámetros estudiados en la matriz agua fueron carbón orgánico, pH, alcalinidad total, alcalinidad al carbonato, dióxido de carbono total, dióxido de carbono libre, presión parcial de CO2, y contenidos de bicarbonato y carbonato. Los compuestos de carbono orgánico e inorgánico tuvieron una distribución muy he...

  18. La Costa Brava en Catalunya: del tradicional modelo de sol y playa a las nuevas opciones de turismo cultural

    OpenAIRE

    2011-01-01

    La Costa Brava, es un destino turístico de litoral consolidado basado en el turismo de sol y playa. Con el objetivo de paliar su posible declive, según el tradicional ciclo de vida de los productos turísticos de Butler (1980) y las teorías de la reestructuración productiva de Agarwal (2002, 2005), considerando el impacto de las nuevas tendencias de mercado en los destinos turísticos consolidados, la Costa Brava ha evolucionado hacia una oferta de múltiples actividades recreativas como medidas...

  19. Clasificación e impacto ambiental de los residuos sólidos generados en las playas de Riohacha, La Guajira, Colombia

    OpenAIRE

    Elin Márquez Gulloso; Jairo Rafael Rosado Vega

    2011-01-01

    En la presente investigación se realizó una clasificación y valoración de impacto de los residuos sólidos generados en las playas de Riohacha, desde Valle de los Cangrejos hasta el Barrio Marbella. Se seleccionaron cinco estaciones de muestreo; en cada una se ubicaron transectos perpendiculares a la línea de costa; sobre estos se trazaron cuadrantes paralelos para la recolección de residuos sólidos. Además, se aplicaron encuestas a los usuarios y vendedores de las playas para determinar la pe...

  20. Impactos de corto plazo del huracán Dean sobre la morfología de la playa de Cancún, México

    OpenAIRE

    Raúl Martell-Dubois; Edgar Mendoza Baldwin; Ismael Mariño Tapia; Rodolfo Silva-Casarín; Edgar Escalante Mancera

    2012-01-01

    En las últimas tres décadas, la playa de Cancún, ubicada en el estado de Quintana Roo, en el Caribe mexicano, ha experimentado procesos erosivos que han degradado sus condiciones de uso, de manera tal que se ha requerido la realización de dos campañas de alimentación artificial de arena. El objetivo del presente trabajo es determinar los impactos de corto plazo del paso del huracán Dean sobre la morfología, ya alterada, de la playa de Cancún, luego del primer relleno en 2006. El análisis comb...

  1. La integración del territorio interior como incentivador de desarrollo turístico: caso Playas de Rosarito (México)

    OpenAIRE

    Jorge Carlos MORGAN MEDINA; Cuamea Velázquez, Onésimo; Valle Ascensio, Ramona; Moreno Moreno, Luis Ramón

    2010-01-01

    Playas de Rosarito es el municipio de más reciente creación y con mayor vocación turística de Baja California. Alrededor de su principal atractivo, el sol y la playa, opera una creciente oferta de servicios de hospedaje, alimentación y espacios para la recreación y el esparcimiento, y últimamente un importante crecimiento de turismo de segunda residencia; sin embargo, la proliferación de discotecas ha propiciado la afluencia de un turismo juvenil con poca capacidad de gasto que se interesa má...

  2. Disponibilidad de arena para el refulado de las playas de Miramar y Chapadmalal, Argentina Sand availability for nourishment of the Miramar and Chapadmalal beaches, Argentina

    OpenAIRE

    FI Isla

    2003-01-01

    Las playas de Miramar se originaron por los aportes naturales transportados directamente como médanos transversales desde el oeste, aunque estas arenas son de origen marino que llegaron a la costa por la acción de olas. Cuando ese aporte de arena mermó debido a la forestación de los médanos del Vivero Ameghino, se debió recurrir a espigones rígidos, que luego debieron ser prolongados para mantener una anchura suficiente de las playas para los requerimientos balnearios. Hoy día el repoblamient...

  3. METODOLOGÍA DE CÁLCULO DE LA CAPACIDAD DE CARGA TURÍSTICA COMO HERRAMIENTA PARA LA GESTIÓN AMBIENTAL Y SU APLICACIÓN EN CINCO PLAYAS DEL CARIBE NORTE COLOMBIANO

    Directory of Open Access Journals (Sweden)

    BOTERO SALTARÉN CAMILO

    2010-05-01

    Full Text Available Este artículo presenta una metodología para medir la capacidad de carga en playas turísticas, más allá del solo componente ambiental. Además, concibe la playa como un sistema complejo en movimiento hacia su desarrollo sostenible. Se seleccionaron y clasificaron cinco playas del Caribe Norte Colombiano, a través de cuatro sub- usos turísticos: intensivo, de conservación, compartido y étnico. Con revisiones normativas, trabajo de campo y diseño de indicadores, se analizaron el soporte ambiental, el equipamiento urbano y los servicios conexos de las playas. Como resultado se estableció un nuevo modelo para medir la capacidad de carga en playas turísticas y se aplicó en las playas de estudio. También se presentan las condiciones actuales de las playas de estudio, su capacidad de carga turística actual y algunas acciones de manejo en cada componente. La principal conclusión se dirige a integrar las condiciones naturales como factor central de la gestión de playas, pero desde un enfoque holístico en el proceso de toma de decisiones. Finalmente, se pone en alerta frente a las condiciones de las playas colombianas y las medidas a tomar en el corto y mediano plazo. Este documento es el resultado del proyecto “Determinación de un sistema de calificación y certificación de playas turísticas”.

  4. Hydrologic description of Lake Hancock, Polk County, Florida

    Science.gov (United States)

    Hammett, K.M.; Snell, L.J.; Joyner, Boyd F.

    1981-01-01

    Available data were evaluated to document hydrologic conditions in the Lake Hancock basin. Bathymetric data indicate that Lake Hancock is very shallow, having a maximum depth of about 3 feet. The lake bottom is covered by a layer of organic material that may be more than 5 feet thick near the center of the lake. Lake Hancock 's stage fluctuates within 0.5 foot of average stage about 40 percent of the time. Lake outflow is through an operable control. There are many days with no outflow in some years. A water-budget analysis of the lake indicates that substantial lake stage declines in 1968 and 1975 followed successive years of deficient precipitation and were primarily the result of a net loss of water from the lake to the ground-water system. During a period in 1971-72 when lake stage remained relatively stable, the ground-water system contributed a significant volume of water to the lake. Water-quality data indicate that Lake Hancock is in a eutrophic state. The eutrophication process appears to have been accelerated through the addition of nutrients from inflow of wastewater effluent from secondary treatment plants. (USGS)

  5. Building on previous OSL dating techniques for gypsum: a case study from Salt Basin playa, New Mexico and Texas

    Science.gov (United States)

    Mahan, Shannon; Kay, John

    2012-01-01

    The long term stability and reliability of the luminescence signal for gypsum has not been well documented or systematically measured until just recently. A review of the current literature for luminescence dating of gypsum is compiled here along with original efforts at dating an intact and in-situ bed of selenite gypsum at Salt Basin Playa, New Mexico and Texas. This effort differs from other documented luminescence dating efforts because the gypsum is not powdery or redistributed from its original growth patterns within the playa basin but is instead of a crystalline form. Sixteen ages from eight cores were ultimately produced with seven of the ages coming from rare detrital quartz encased in or with the gypsum crystals while the remaining ages are from the crystalline gypsum. As far as can be ascertained, the quartz was measured separately from the gypsum and no contaminants were noted in any of the aliquots. Some basic and preliminary tests of signal stability were measured and found to be mitigated by lessening of pre-heat protocols. Ages ranged from 8 ka to 10 ka in the shallow cores and 16 ka to 22 ka in the deeper cores. These ages will be useful in determining rates of gypsum growth within a sequence of evaporates which, in turn, will help to better document historic rates of evaporation and thus estimate, with more precision, the corresponding annual evaporation rates.

  6. A new ranavirus isolated from Pseudacris clarkii tadpoles in playa wetlands in the southern High Plains, Texas.

    Science.gov (United States)

    Torrence, Shannon M; Green, D Earl; Benson, Catherine J; Ip, Hon S; Smith, Loren M; McMurry, Scott T

    2010-06-01

    Mass die-offs of amphibian populations pose a challenging problem for conservation biologists. Ranaviruses often cause systemic infections in amphibians and, in North America, are especially virulent and lethal to larvae and metamorphs. In this paper we describe a novel ranavirus isolate as well as the first recorded occurrence of ranavirus in the southern High Plains of Texas and in associated populations of the spotted chorus frog Pseudacris clarkii. The breeding sites were playas, that is, wetlands that fill via isolated thunderstorms that can occur infrequently; thus, not every playa has water or breeding amphibians annually. We did not detect ranavirus in sympatric anurans, but other reports document ranaviruses in Pseudacris spp. elsewhere. The occurrence of multiple isolates of ranavirus in a number of Pseudacris species suggests that this genus of frogs is highly susceptible to ranaviruses and may experience exceptionally high mortality rates from infection. Thus, the virus may contribute to substantial seasonal population declines and low seasonal recruitment, with negative impacts on populations of breeding adults in successive years.

  7. Aportes del turismo según los habitantes de las comunidades de Playas del Coco, Guanacaste y el Roble, Puntarenas

    Directory of Open Access Journals (Sweden)

    Jorge Bartels Villanueva

    2012-09-01

    Full Text Available Este trabajo se basa en los artículos titulados “Impacto del Turismo, el caso de: El Roble 2 de Puntarenas” y “Allá en Playas del Coco; donde el turismo no fue amor de temporada”, que se obtuvieron a partir de la investigación realizada por el equipo del proyecto Desarrollo de la investigación INTERSEDES, mediante el estudio y el fortalecimiento del turismo sostenible en las provincias de Limón, Puntarenas y Guanacaste” desarrollado, durante el año 2009 y 2010, en las comunidades de Playas del Coco y el Roble 2 de Puntarenas. El objetivo de la investigación era determinar el impacto del turismo sobre estas comunidades y más específicamente se quería caracterizar a los hogares, conocer la composición de la población económicamente activa, conocer la fuente de los ingresos individuales y familiares y las opiniones que esa población tiene sobre el turismo, la cultura local y el papel de las instituciones locales en el desarrollo de esas comunidades. En nuestro caso queremos comparar esas mismas variables en dos focos de turismo nacional, con características diferentes, para determinar como ven esas comunidades al turismo como actividad de desarrollo local.

  8. Biología pesquera de la langosta Panulirus gracilis en Playa Lagarto, Guanacaste, Costa Rica

    Directory of Open Access Journals (Sweden)

    Helven Naranjo Madrigal

    2011-06-01

    Full Text Available Los parámetros biológicos y pesqueros analizados se fundamentaron en una muestra de 843 langostas provenientes de la actividad pesquera realizada en Playa Lagarto entre noviembre del 2007 y octubre del 2008. Las longitudes cefalotoráxicas de los machos estuvo comprendida entre los 143.6 y 42.8 y 115 y 35.8mm para hembras. El 74.9% de las langostas en los desembarques estuvo por debajo de la talla mínima legal de captura (80 mm de LC. La estructura de tallas muestra un considerable solapamiento de segmentos poblacionales y el incremento de las tallas con la profundidad en donde operan las dos modalidades de pesca estudiadas: el buceo a pulmón y el buceo con compresor. La proporción de sexos obtenida fue de 1.36 M:H. La relación entre LC y peso reveló que las hembras pesan más que los machos de una misma talla y que esta diferencia fue significativa (p<0.05. Los parámetros de crecimiento de von Bertalanffy para machos y hembras respectivamente (K=0.45-0.38, LC∞=166.9-121.7 indican un crecimiento acelerado en comparación a otras especies. Los machos por su parte exhibieron una mayor tasa de crecimiento que las hembras. Además, la mortalidad natural (M, la mortalidad total (Z y la mortalidad por pesca (F fue más alta en machos (0.49-2.34-1.92 que en hembras (0.47-1.82-1.42. El reclutamiento para ambos sexos presentó un comportamiento continuó durante el año con un pulso de mayor intensidad en julio de 18.5%. El significativo porcentaje de langostas por debajo de la talla mínima legal permitida para la pesca evidencia fuerte presión ejercida sobre las tallas juveniles. Afirmación que es reforzada por el valor de la tasa de explotación (E determinada de 0.80, que indica que bajo el actual régimen de pesca la población estaría en riesgo de colapso.

  9. NESTING HABITAT OF THE ‘CUPISO’ Podocnemis sextuberculata (TESTUDINES: PODOCNEMIDIDAE IN EREPECU LAKE (PARÁ-BRAZIL

    Directory of Open Access Journals (Sweden)

    Ana Lucia Bermúdez Romero

    2014-09-01

    Full Text Available The objective of this study was to identify and describe the nesting habitat of Podocnemis sextuberculata at Erepecu Lake, Trombetas River Biological Reserve, (REBIO-Trombetas; Pará-Brazil. Initially, the main features of the beaches that potentially determine the habitat selection by cupiso for nesting were described. The nests observed on the beaches were recorded, marked and fenced as protection from natural predators. Information regarding date and location was analyzed with simple linear regression for each nest in order to determine relationships between beach features and number of nests. The results showed a positive co-relationship between number of nests and area. Nest site selection by P. sextuberculata in the beaches of the Erepecu Lake could depend on trade-off scenarios among natural threats and a suitable nesting habitat. We also suggest that, due to the high annual hydrologic oscillations on the beaches, it is possible that the driving factor for habitat selection would be the risks that the species is exposed to at the time of the search for a nesting site, rather than seeking a particular habitat type.  RESUMENEl objetivo del estudio fue identificar y explicar la influencia del hábitat sobre los nidos de la tortuga “cupiso” (Podocnemis sextuberculata Cornalia, 1849, en el lago Erepecu ubicado en la Reserva Biológica del Río Trombetas (REBIO-Trombetas; Pará-Brasil. Inicialmente se describieron las principales características de las playas escogidas, los nidos encontrados fueron marcados y cercados para su protección contra la depredación natural. A través de regresiones lineales simples se determinó que el número de nidos por playa se correlacionó significativamente con el “área” de las playas.  Los resultados muestran que la selección del lugar de nidificación en las playas del lago Erepecu por P. sextuberculata, podría depender en unos escenarios de compensación entre las amenazas naturales y un h

  10. Non-Vegetated Playa Morphodynamics Using Multi-Temporal Landsat Imagery in a Semi-Arid Endorheic Basin: Salar de Uyuni, Bolivia

    NARCIS (Netherlands)

    Li, J.; Menenti, M.; Mousivand, A.; Luthi, S.M.

    2014-01-01

    Playas in endorheic basins are of environmental value and highly scientific because of their natural habitats of a wide variety of species and indicators for climatic changes and tectonic activities within continents. Remote sensing, due to its capability of acquiring repetitive data with synoptic c

  11. CUANTIFICACIÓN DEL CARBÓN MINERAL EN LAS PLAYAS DEL CARIBE COLOMBIANO (DEPARTAMENTO DEL MAGDALENA

    Directory of Open Access Journals (Sweden)

    JULIÁN ANDRÉS GARCÍA MURCIA

    2014-01-01

    Full Text Available Con el fin de cuantificar el porcentaje de carbón mineral en playas del departamento del Magdalena, (Colombia se llevó a cabo un procedimiento sencillo para separar el sedimento en fracciones sedimentológicas de acuerdo a su densidad. Se utilizaron sedimentos provenientes de seis playas del departamento colectadas de dos niveles mareales en noviembre de 2012 y febrero de 2013, antes y después de un derrame de una barcaza de carbón, que ocurrió el 12 de enero de 2013. Los sedimentos fueron secados, suspendidos en una solución de sodio politungstato (densidad: 2,0 g·cm-3 y centrifugados. Ya que el carbón tiene una densidad menor (1,2-1,9 g·cm-3 que otros minerales inorgánicos, cualquier partícula de carbón presente en una muestra se concentró en la fracción ligera, mientras que las partículas más densas se sedimentaron. Para eliminar materia orgánica no correspondiente a carbón mineral, se sometió la fracción ligera después a una oxidación leve con peróxido de hidrógeno. Adicionalmente, para estimar un límite máximo del contenido de carbón mineral, se determinó la pérdida de peso de sedimentos enteros a partir de combustión a 550 °C. En las seis playas evaluadas, la pérdida máxima de peso por combustión fue de 2,4 % y el porcentaje máximo de la fracción ligera (densidad 3 g·cm-3 y que constituyen entre 10 y 70 % del peso seco total de las muestras.

  12. ESTUDIO DEL RENDIMIENTO ACADÉMICO EN ATLETAS ADOLESCENTES DEL CLUB DE ATLETISMO PLAYAS DE CASTELLÓN [Academic performance study in young athletes from Playas de Castellón Athletics Club

    OpenAIRE

    Ana Capdevila Seder; Héctor Bellmunt Villalonga; Carlos Hernando Domingo

    2014-01-01

    El estudio analizó la posible relación entre el rendimiento académico de jóvenes atletas y algunas de las variables más utilizadas en este campo. La muestra estaba compuesta por 40 atletas del Club de Atletismo Playas de Castellón, con edades comprendidas entre 14 y 16 años, 22 hombres y 18 mujeres. Las principales variables analizadas fueron el rendimiento académico, los hábitos de estudio, el género, las horas de sueño, el ocio sedentario, el nivel socioeconómico y la dedicación al deporte....

  13. Progress in understanding the importance of coastal wetland nursery habitat to Great Lakes fisheries support

    Science.gov (United States)

    Great Lakes coastal wetlands provide important habitat for Great Lakes fishes of all life stages. A literature review of ichthyoplankton surveys conducted in Great Lakes coastal wetlands found at least 82 species reported to be captured during the larval stage. Twenty of those sp...

  14. Great Lakes

    Science.gov (United States)

    Edsall, Thomas A.; Mac, Michael J.; Opler, Paul A.; Puckett Haecker, Catherine E.; Doran, Peter D.

    1998-01-01

    The Great Lakes region, as defined here, includes the Great Lakes and their drainage basins in Minnesota, Wisconsin, Illinois, Indiana, Ohio, Pennsylvania, and New York. The region also includes the portions of Minnesota, Wisconsin, and the 21 northernmost counties of Illinois that lie in the Mississippi River drainage basin, outside the floodplain of the river. The region spans about 9º of latitude and 20º of longitude and lies roughly halfway between the equator and the North Pole in a lowland corridor that extends from the Gulf of Mexico to the Arctic Ocean.The Great Lakes are the most prominent natural feature of the region (Fig. 1). They have a combined surface area of about 245,000 square kilometers and are among the largest, deepest lakes in the world. They are the largest single aggregation of fresh water on the planet (excluding the polar ice caps) and are the only glacial feature on Earth visible from the surface of the moon (The Nature Conservancy 1994a).The Great Lakes moderate the region’s climate, which presently ranges from subarctic in the north to humid continental warm in the south (Fig. 2), reflecting the movement of major weather masses from the north and south (U.S. Department of the Interior 1970; Eichenlaub 1979). The lakes act as heat sinks in summer and heat sources in winter and are major reservoirs that help humidify much of the region. They also create local precipitation belts in areas where air masses are pushed across the lakes by prevailing winds, pick up moisture from the lake surface, and then drop that moisture over land on the other side of the lake. The mean annual frost-free period—a general measure of the growing-season length for plants and some cold-blooded animals—varies from 60 days at higher elevations in the north to 160 days in lakeshore areas in the south. The climate influences the general distribution of wild plants and animals in the region and also influences the activities and distribution of the human

  15. Mid Holocene lake level and shoreline behavior during the Nipissing phase of the upper Great Lakes at Alpena, Michigan, USA

    Science.gov (United States)

    Thompson, T.A.; Lepper, K.; Endres, A.L.; Johnston, J.W.; Baedke, S.J.; Argyilan, E.P.; Booth, R.K.; Wilcox, D.A.

    2011-01-01

    The Nipissing phase was the last pre-modern high-water stage of the upper Great Lakes. Represented as either a one- or two-peak highstand, the Nipissing occurred following a long-term lake-level rise. This transgression was primarily an erosional event with only the final stage of the transgression preserved as barriers, spits, and strandplains of beach ridges. South of Alpena, Michigan, mid to late Holocene coastal deposits occur as a strandplain between Devils Lake and Lake Huron. The landward part of this strandplain is a higher elevation platform that formed during the final stage of lake-level rise to the Nipissing peak. The pre-Nipissing shoreline transgressed over Devils Lake lagoonal deposits from 6.4 to 6.1. ka. The first beach ridge formed ~ 6. ka, and then the shoreline advanced toward Lake Huron, producing beach ridges about every 70. years. This depositional regression produced a slightly thickening wedge of sediment during a lake-level rise that formed 20 beach ridges. The rise ended at 4.5. ka at the Nipissing peak. This peak was short-lived, as lake level fell > 4. m during the following 500. years. During this lake-level rise and subsequent fall, the shoreline underwent several forms of shoreline behavior, including erosional transgression, aggradation, depositional transgression, depositional regression, and forced regression. Other upper Great Lakes Nipissing platforms indicate that the lake-level change observed at Alpena of a rapid pre-Nipissing lake-level rise followed by a slower rise to the Nipissing peak, and a post-Nipissing rapid lake-level fall is representative of mid Holocene lake level in the upper Great Lakes. ?? 2011 Elsevier B.V.

  16. Late Quaternary stratigraphy, sedimentology, and geochemistry of an underfilled lake basin in the Puna (north-west Argentina)

    Science.gov (United States)

    McGlue, Michael M.; Cohen, Andrew S.; Ellis, Geoffrey S.; Kowler, Andrew L.

    2013-01-01

    Depositional models of ancient lakes in thin-skinned retroarc foreland basins rarely benefit from appropriate Quaternary analogues. To address this, we present new stratigraphic, sedimentological and geochemical analyses of four radiocarbon-dated sediment cores from the Pozuelos Basin (PB; northwest Argentina) that capture the evolution of this low-accommodation Puna basin over the past ca. 43 cal kyr. Strata from the PB are interpreted as accumulations of a highly variable, underfilled lake system represented by lake-plain/littoral, profundal, palustrine, saline lake and playa facies associations. The vertical stacking of facies is asymmetric, with transgressive and thin organic-rich highstand deposits underlying thicker, organic-poor regressive deposits. The major controls on depositional architecture and basin palaeogeography are tectonics and climate. Accommodation space was derived from piggyback basin-forming flexural subsidence and Miocene-Quaternary normal faulting associated with incorporation of the basin into the Andean hinterland. Sediment and water supply was modulated by variability in the South American summer monsoon, and perennial lake deposits correlate in time with several well-known late Pleistocene wet periods on the Altiplano/Puna plateau. Our results shed new light on lake expansion–contraction dynamics in the PB in particular and provide a deeper understanding of Puna basin lakes in general.

  17. Estudio del rendimiento académico en atletas adolescentes del Club de Atletismo Playas de Castellón

    OpenAIRE

    Capdevila Seder, Ana; Bellmunt Villalonga, Hector; Hernando Domingo, Carlos

    2014-01-01

    El estudio analizó la posible relación entre el rendimiento académico de jóvenes atletas y algunas de las variables más utilizadas en este campo. La muestra estaba compuesta por 40 atletas del Club de Atletismo Playas de Castellón, con edades comprendidas entre 14 y 16 años, 22 hombres y 18 mujeres. Las principales variables analizadas fueron el rendimiento académico, los hábitos de estudio, el género, las horas de sueño, el ocio sedentario, el nivel socioeconómico y la dedicación al deporte....

  18. Evolución de la calidad de las aguas de playa de la ciudad de Puntarenas 1961- 2001

    Directory of Open Access Journals (Sweden)

    Darner A. Mora Alvarado

    2002-07-01

    Full Text Available El presente documento muestra la evolución de la calidad sanitaria de las aguas de playa de la ciudad de Puntarenas durante los últimos cuarenta años. Para la evaluación se utilizan los datos de Coliformes totales presentados por Brunker y Fernández en 1961 y 1971, complementados con los resultados de ese mismo indicador obtenidos en el Laboratorio Nacional de Aguas (LNA entre 1981 y el año 2001, en ambos casos por cada 100 mL de muestra. Los puntos de muestreo seleccionados suman un total de 10, ubicados desde la Punta hasta 200 metros al este del Muelle Nacional. Por otra parte, se realizó otra valoración utilizando los datos de Coliformes fecales obtenidos por el LNA a partir de 1981, calculando los promedios geométricos de los trienios 1981- 1983, 1985-1987, 1990-1992 y 1999-2001. Los resultados indican que en ambos indicadores microbiológicos se observa una disminución en la contaminación fecal, a partir de la década de los 70, lo que permite concluir que las aguas de playa de la ciudad de Puntarenas han mejorado su calidad sanitaria con el transcurso de los años. Las causas de esta mejoría son: La construcción del sistema nuevo del alcantarillado sanitario en 1976. El traslado de la actividad portuaria, del muelle Nacional de Puntarenas a Caldera. Las obras construidas por el MOPT en la Punta. La disminución del turismo y ordenamiento en el alcantarillado por parte de AyA.

  19. 两级臭氧一活性炭组合工艺净化太湖水中试研究%Pilot Study on Two-stage Ozonization and Activated Carbon Process for Taihu Lake Water Purification

    Institute of Scientific and Technical Information of China (English)

    刘洋; 崔云霞

    2011-01-01

    采用两级臭氧-活性炭组合工艺在以太湖水为水源的某水厂进行深度处理中试研究.结果表明:该组合处理工艺对有机污染物有稳定的去除效果,在预臭氧投加重为0.5 mg/L、主臭氧投加量为0.7 mg/L下,相对于原水对CODMn,UV254(紫外吸光度),DOC,THMEP,氨氮,亚硝酸盐氮和硝酸盐氨的平均去除率分别为47.06%,80%,31.92%,58.9%,65.5%,81.25%和9.1%,出永满足GB 5749-2006《生活饮用水卫生标准》的要求,炭滤池出水中臭氧消毒副产物均低于标准限值,组合工艺对有害物质冲击负荷有一定的抵抗能力.%The pilot experiments were carried out to investigate the advanced treatment by the combined process of two-stage ozonization and activated carbon in a plant using Taihu Lake water as raw water. The results showed that the removal of organic pollutants by the combined process was stable. Relative to the raw water, the average removal rates of CODmns UV254, DOC, THMEP, ammonia nitrogen, nitrite nitrogen and nitrate nitrogen were 47.06%, 80%, 31.92%, 58.9%, 65.3%, 81.25% and 9.1% respectively, when the pre-ozonizaiton dosage was 0.5mg/L and the main ozonization dosage was 0.7mg/L. The effluent could meet "Standards of Drinking Water Quality "(GB 5749-2006). The disinfection by-products of ozone were lower than the standard limit in the effluent from carbon filter. The combined process has some resistibility to the impact load of hazardous substances.

  20. Subglacial Lake McGregor, south-central Alberta, Canada

    Science.gov (United States)

    Munro-Stasiuk, Mandy J.

    2003-08-01

    It is proposed that a lake, here named "Subglacial Lake McGregor", existed beneath the Laurentide Ice Sheet at, or near, the last glacial maximum. The lake resided in the ancient buried McGregor and Tee Pee preglacial valleys, which are now mostly filled with glacigenic deposits. The greatest thickness of sediment in the valleys is in the form of chaotically deposited lake beds that were laid down in a subaqueous environment by a number of process: gravity flow, water transport, and suspension settling. Topographic, sedimentary, and stratigraphic evidence point to a subglacial, not a proglacial, origin for the beds. During the early stages of lake existence, ice movement was significant as there are numerous sets of shear planes in the sedimentary beds. This indicates that the lake filled (lake sedimentation) and drained (shearing of the beds by overlying ice when ice contacted the bed) often. Thus, early in its history, the lake(s) was/were ephemeral. During the later stages of lake existence, the lake was relatively stable with no rapid draining or influx of sediment. Gradual drainage of the lake resulted in lowering of the ice onto the lake beds resulting in subglacial till deposition. Drainage was not a single continuous event. Rather it was characterized by multiple phases of near total drainage (till deposition), followed by water accumulation (lake sedimentation). Water accumulation events became successively less significant reflected by thinning of lake beds and thickening of till beds higher in the stratigraphic sequence. Since subglacial lake sedimentation appears to be restricted to the subglacial valleys, it is suggested that the valleys acted as a large-scale interconnected cavity system that both stored and transported water. It is also suggested that these acted as the main routes of water flow beneath the Laurentide Ice Sheet.

  1. Bathymetry of Lake Michigan

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Bathymetry of Lake Michigan has been compiled as a component of a NOAA project to rescue Great Lakes lake floor geological and geophysical data and make it more...

  2. Bathymetry of Lake Ontario

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Bathymetry of Lake Ontario has been compiled as a component of a NOAA project to rescue Great Lakes lake floor geological and geophysical data and make it more...

  3. Designated Wildlife Lakes - points

    Data.gov (United States)

    Minnesota Department of Natural Resources — This is a point shapefile of Designated Wildlife Lakes in Minnesota. This shapefile was created by converting lake polygons from the Designated Wildlife Lakes...

  4. Great Lakes Bathymetry

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Bathymetry of Lakes Michigan, Erie, Saint Clair, Ontario and Huron has been compiled as a component of a NOAA project to rescue Great Lakes lake floor geological and...

  5. Bathymetry of Lake Superior

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Bathymetry of Lake Superior has been compiled as a component of a NOAA project to rescue Great Lakes lake floor geological and geophysical data and make it more...

  6. Hydrography - Lakes Assessments - Attaining

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — This layer shows only attaining lakes of the Integrated List. The Lakes Integrated List represents lake assessments in an integrated format for the Clean Water Act...

  7. Bathymetry of Lake Huron

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Bathymetry of Lake Huron has been compiled as a component of a NOAA project to rescue Great Lakes lake floor geological and geophysical data and make it more...

  8. Reflexión sobre el impacto de los museos tarraconenses en el turismo. Alternativa al producto de sol y playa

    Directory of Open Access Journals (Sweden)

    Sara Mestre Batet

    2010-01-01

    Full Text Available Cataluña siempre ha sido identificada como un destino de sol y playa. Aún así, cada vez son más los turistas que buscan una diferenciación en el producto y vienen motivados por el turismo cultural. Actualmente, se está transformando la imagen de esta región ya que se pone en auge el patrimonio. Una de las herramientas para conseguirlo son las infraestructuras culturales, esencialmente, los museos. En el caso de Tarragona, con su producto estrella hasta ahora centrado en las playas de la Costa Dorada, comprobaremos que incidencia tienen sus museos en los residentes y visitantes de esta ciudad activamente cultural (aspectos positivos y negativos y abalada por la Unesco como Patrimonio de la Humanidad desde el año 2000. Y como ello es una ayuda para desmasificar la costa y ofrecer un producto complementario.

  9. ESTUDIO DEL RENDIMIENTO ACADÉMICO EN ATLETAS ADOLESCENTES DEL CLUB DE ATLETISMO PLAYAS DE CASTELLÓN [Academic performance study in young athletes from Playas de Castellón Athletics Club

    Directory of Open Access Journals (Sweden)

    Ana Capdevila Seder

    2014-04-01

    Full Text Available El estudio analizó la posible relación entre el rendimiento académico de jóvenes atletas y algunas de las variables más utilizadas en este campo. La muestra estaba compuesta por 40 atletas del Club de Atletismo Playas de Castellón, con edades comprendidas entre 14 y 16 años, 22 hombres y 18 mujeres. Las principales variables analizadas fueron el rendimiento académico, los hábitos de estudio, el género, las horas de sueño, el ocio sedentario, el nivel socioeconómico y la dedicación al deporte. Los instrumentos utilizados fueron los cuestionarios CHTE (Cuestionario de Hábitos y Técnicas de Estudio, PFYTL (Práctica Física Y uso del Tiempo Libre y el Cuestionario destinado a los padres. Los resultados mostraron que el rendimiento académico correlacionaba de forma positiva con la dedicación al deporte y de forma negativa con las horas de sueño. Además, el género femenino tuvo un rendimiento académico superior al masculino. AbstractThe study analyzed the possible relationship between academic performance of young athletes and some of the variables most used in this field. The sample consisted of 40 athletes Athletics Club Playas de Castellón, between 14 and 16 years, 22 boys and 18 girls. The main variables analyzed were academic performance, study habits, gender, sleep, sedentary leisure, socioeconomic status and dedication to sport. The instruments used were questionnaires CHTE (habits and study skills, PFYTL (physical practice and use of leisure time and the Questionnaire for parents. The results showed that academic performance was positively correlated with the dedication to sport and negatively with sleep. In addition, the female gender had a higher performance than male. Key words: academic performance; dedication to sport; study habits; leisure.

  10. Portafolio “Áreas de arrecifes de coral, pastos marinos, playas de arena y manglares con potencial de restauración en Colombia.

    OpenAIRE

    Gómez Cubillos, Catalina; Licero, Lucia; Perdomo, Laura; Rodríguez, Angélica María; Romero D'Achardi, Diana Carolina; Ballesteros Contreras, Diana Carolina; Gómez López, Diana Isabel; Melo Valencia, Andrés Felipe; Chasqui, Luis; Ocampo Rojas, María Alejandra; Alonso, David; García Murcia, Julián Andrés; Peña Mejía, Carlos Eduardoi; Bastidas Salamanca, Martha Lucero; Ricaurte Villota, Constanza

    2015-01-01

    Producto final de la implementación de una metodología diseñada por el grupo de investigadores de INVEMAR, con la que se evaluó el estado, las causas de deterioro y la demanda de servicios de los ecosistemas, con el propósito de priorizar las áreas de arrecifes de coral, praderas de pastos marinos, playas de arena y sectores de manglar con potencial de restauración en Colombia.

  11. Great Lakes Science Center

    Data.gov (United States)

    Federal Laboratory Consortium — Since 1927, Great Lakes Science Center (GLSC) research has provided critical information for the sound management of Great Lakes fish populations and other important...

  12. Anidación de la tortuga Dermochelys coriacea (Testudines: Dermochelyidae en playa Gandoca, Costa Rica (1990 a 1997

    Directory of Open Access Journals (Sweden)

    Didiher Chacón Chaverri

    1999-06-01

    Full Text Available La anidación de la tortuga baula fue estudiada en playa Gandoca, una importante playa de anidación de tortugas marinas localizada al sureste de la costa Caribeña de Costa Rica, dentro de los límites del Refugio Nacional de Vida Silvestre Gandoca/Manzanillo (82° 37' O, 09° 37' N. Entre 1990 y 1997, se desarrollaron campañas de observación de la anidación entre los meses de febrero a julio de cada año; 16 variables de la anidación fueron anotadas y una parte de la colonia fue marcada con marcas monel y 3 484 nidos fueron encontrados; durante este periodo se depositaron un promedio de 534 nidos por temporada, 1,135 nidos fue el máximo de anidación anual, mientras que 226 nidos fue el mínimo, el 20.8% de los nidos fueron relocalizados en los viveros. El promedio de la longitud curva del caparazón de las hembras fue de 154.65 cm y el promedio del ancho curvo del caparazón fue de 112.83 cm. Las observaciones mostraron que el promedio de huevos normales para este periodo fue de 79.28, mientras que el promedio de huevos vanos fue de 35. La recolección ilegal de huevos, la basura sobre la playa y la erosión intensiva son parte de los problemas más importantes que están causando el declive de las tortugas en Gandoca.The nesting of the leatherback sea turtle was studied in Gandoca Beach, an important nesting beach on the southeastern Caribbean coast of Costa Rica, in the Gandoca/Manzanillo National Wildlife Refuge. Nesting was recorded from 1990 to 1997 (each February through July. Nesting peaked in April and May (depending on the year; 16 biological paramenters were recorded and part of the rookery was tagged with monel tags. During this period 1 045 females were studied and 3 484 nests were recorded; 534 nests was the yearly mean, (range 226-1 135, 20.8 % of the nests were relocated to hatcheries, as a conservation effort to prevent loss of nests. Mean curve carapace length was 154.65 cm and width 112.83 cm. Mean normal number of eggs

  13. "Greatest lake period"and its palaeo-environment on the Tibetan Plateau

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The“greatest lake perion”means that the lakes are in the stage of their maximum areas.As the paleo lake shorelines are widely distributed in the lake basins on the Tibetan Plateau,the lake areas during the “greatest lake period”may be inferred by the last highest lake shorelines.They are several,even tens times larger than that at present.According to the analyses of tens of lakes on the Plateau,most dating data fell into the range of 40-25 ka BP,some lasted to 20 ka BP.It was corresponded to the stage 3 of marine isotope and interstitial of last glaciation.The occurrence of maximum areas of lakes marked the very humid period on the Plateau and was also related to the stronger summer monsoon during that period.

  14. Intertonguing of the Lower Part of the Uinta Formation with the Upper Part of the Green River Formation in the Piceance Creek Basin During the Late Stages of Lake Uinta

    Science.gov (United States)

    Donnell, John R.

    2009-01-01

    During most of middle Eocene time, a 1,500-mi2 area between the Colorado and White Rivers in northwestern Colorado was occupied by the Piceance lobe of Lake Uinta. This initially freshwater lake became increasingly saline throughout its history. Sediments accumulating in the lake produced mostly clay shale, limestone, and dolomite containing varying concentrations of organic matter. At the time of the maximum extent of the lake, the organic-rich Mahogany bed of the Green River Formation was deposited throughout the area. Shortly after its deposition, stream deposits began infilling the lake from the north through a series of contractions interspersed with minor expansions. This fluctuation of the shoreline resulted in the intertonguing of the stream sediments of the lower part of the overlying Uinta Formation with the lacustrine sediments of the upper part of the Green River over a distance of about 40 mi; construction of regional stratigraphic cross sections show the pattern of intertonguing in considerable detail. The data utilized in this study, which covered parts of Rio Blanco, Garfield, and Mesa counties, was derived from (1) geologic mapping of thirty-four 7 1/2-minute quadrangles and stratigraphic studies by geologists of the U.S. Geological Survey, and (2) shale-oil assay information from numerous cores. As a result of this previous work and the additional effort involved in the compilation here presented, more than a dozen Green River Formation tongues have been named, some formally, others informally. Middle Eocene strata above the Mahogany bed in the northern part of the study area are dominantly coarse clastics of the Uinta Formation. The sedimentary sequence becomes more calcareous and organic-rich to the south where, in a 400-mi2 area, a 250 ft-thick sequence of oil shale above the Mahogany bed contains an average of 16 gallons of oil per ton of shale and is estimated to contain 73 billion barrels of oil.

  15. Comparative Study on the Muscle Composition of Lake Anchovy (Coilia Eetenes taihuensis) in Different Growth Stages%湖鲚不同生长阶段鱼体肌肉组成的比较研究

    Institute of Scientific and Technical Information of China (English)

    段金荣; 刘凯; 徐东坡; 张敏莹; 施炜纲

    2009-01-01

    对来自太湖五里湖的湖鲚(Coilia ectenes taihuensis)完成年龄鉴定、肌肉营养成分的测定和营养品质的比较.结果表明:湖鲚肌肉(鲜样)中蛋白质和脂肪含量显著高于其它常规经济鱼类.各年龄段湖鲚肌肉中均含18种氨基酸,1龄、2龄、3龄的氨基酸总量占干物质重量百分比分别是(73.32±0.12)%,(74.96±0.14)%,(75.82±0.17)%,其中必需氨基酸总量占总氨基酸百分比为(39.74±1.37)%,(40.42±2.71)%,(39.79±1.49)%,必需氨基酸指数分别为77.17,76.26,76.91,其评价标准满足FAO/WHO的要求,4种鲜味氨基酸总量占干物质重量百分比分别是(28.49±0.06)%,(28.97±0.07)%,(29.31±0.07)%;脂肪酸中EPA和DHA含量均很高,矿物元素比值合理.%Age identification, measure of muscle nutrient content and nutritional quality comparison of Coilia ectenes taihuensis from Taihu Lake were completed. The results showed that protein and fat content of C. ectenes taihuensis were relatively higher than those of others economic fishes. There were 18 kinds of amino acid in the muscle of C. ectenes taihuensis in different growth stages. The percentage of total amino acid to dry matter in the muscles of 1-year-old, 2-year-old and 3-year-old C. ectenes taihuensis were 73.32±0.12, 74.96±0.14 and 75.82±0.17, respectively and the percentage of essential amino acid to total amino acid were 39.74±1.37, 40.42±2.71 and 39.79±1.49, respectively. The indexes of essential amino acid were 77.17, 76.26 and 76.91, respectively. The evaluation criteria of the above indexes met the requirements of FAO/WHO. There were higher EPA and DHA in C. ectenes taihuensis than those in other fishes. The ratio of mineral was relatively reasonable.

  16. Disponibilidad de arena para el refulado de las playas de Miramar y Chapadmalal, Argentina Sand availability for nourishment of the Miramar and Chapadmalal beaches, Argentina

    Directory of Open Access Journals (Sweden)

    FI Isla

    2003-09-01

    Full Text Available Las playas de Miramar se originaron por los aportes naturales transportados directamente como médanos transversales desde el oeste, aunque estas arenas son de origen marino que llegaron a la costa por la acción de olas. Cuando ese aporte de arena mermó debido a la forestación de los médanos del Vivero Ameghino, se debió recurrir a espigones rígidos, que luego debieron ser prolongados para mantener una anchura suficiente de las playas para los requerimientos balnearios. Hoy día el repoblamiento artificial resulta el único método factible de recuperar las playas desde los sectores sumergidos o desde médanos vecinos. Utilizando un sonar de barrido lateral y muestreos de arena se analizó la distribución y calidad de las arenas sumergidas como eventual fuente de alimentación de las playas de Miramar y Chapadmalal. Se estimaron factores de relleno y recurrencia en relación a la granulometría actual de estas playas. La playa sumergida está compuesta principalmente de arena muy fina y se extiende hasta una profundidad de 10-15 m, más allá de la cual se descubren afloramientos de limos entoscados hasta la profundidad de aproximadamente 20 metros. Otro sector arenoso se extiende a profundidades mayores y está dominado por fajas de arena orientadas hacia el NE. Lamentablemente, estas arenas son demasiado finas y por lo tanto no resultarían económicamente aptas para repoblar las playas de Miramar y Chapadmalal.The beaches of Miramar were originated by the migration of transverse dunes from the west of the city, although the provenance of the sand is of marine origin and deposited by wave action. When this input of sand diminished significantly due to the dune fixation at the Ameghino Nature Reserve, a groyne field was emplaced and, after several years, extended to provide a minimum beach width for tourist requirements. Today, artificial beach nourishment is the only method to guarantee enough sand from the near-shore. The distribution

  17. The Pilot Valley shoreline: An early record of Lake Bonneville dynamics: Chapter 3

    Science.gov (United States)

    Miller, David; Phelps, Geoffrey

    2016-01-01

    The Pilot Valley shoreline is named for distinctive gravel beaches on the eastern, northern, and western sides of Pilot Valley playa, Utah. The shoreline has been identified across the Bonneville basin where it is characterized by one to three beach crests between ~ 1305 and 1309 m elevation, all overlain by deep-water marl of Lake Bonneville. It thus represents the lowest and earliest recognized shoreline of Lake Bonneville. Features of the shoreline indicate that both high wave energy and high stream sediment discharge contributed to shoreline development. Basin hypsometry did not play a role in the development of the shoreline, which must have been caused by a combination of climatically driven hydrologic and storm factors, such as reduced precipitation that stabilized lake level and increase in storm-driven wave energy. The Pilot Valley shoreline is poorly dated at about 30 ka. If it is somewhat older, correlation with Greenland Interstadial 5.1 at 30.8–30.6 ka could explain the stabilization of lake level.

  18. Inseguridad y Crisis Económica en el Imaginario Social de Playas de Rosarito, Baja California

    Directory of Open Access Journals (Sweden)

    Jesús Angel Enríquez Acosta

    2015-01-01

    Full Text Available Este trabajo ofrece un análisis acerca de como los habitantes de Playas de Rosarito en Baja California, imaginan y perciben el impacto de la crisis económica norteamericana mas reciente y la inseguridad mexicana en la actividad turística, principal vocación económica del lugar. Los testimonios de los habitantes expresan la transformación social, urbana y cultural del lugar turístico y de los problemas asociados a ciudades en rápido crecimiento. Se trata de una ciudad fronteriza con Estados Unidos donde el turismo asociado al consumo de alcohol y entretenimiento de fin de semana y el turismo de segundas residencias dirigido al norteamericano es dominante. El contexto de la crisis económica, la inseguridad reinante en México condujeron a un decaimiento de la actividad turística y a una sensación de incertidumbre y pesar a los habitantes de esta comunidad.

  19. Diversidad de bacterias cultivables con capacidad de degradar hidrocarburos de la playa de Caleta Córdova, Argentina

    Directory of Open Access Journals (Sweden)

    Graciela N. Pucci

    2011-05-01

    Full Text Available En el presente trabajo se estudiaron las comunidades bacterianas aisladas de agua de mar y sedimentos intermareales de Caleta Córdova, norte de Comodoro Rivadavia, Argentina. Tres sitios fueron muestreados estacionalmente entre los años 2005 y 2006; el primer sitio fue una playa pública, el segundo sitio cerca de un puerto pesquero y el tercero cerca de una boya de toma de petróleo. Las comunidades bacterianas fueron determinadas en base a las diferencias en la composición de ácidos grasos de membrana, las bacterias fueron identificadas por medio del Sistema Sherlock MIDI, y el potencial de las comunidades para la utilización de hidrocarburos por la mineralización de gasoil, petróleo, kerosene, aceite lubricante y nafta. Las mineralizaciones evidenciaron la capacidad de los microorganismos para la degradación de hidrocarburos en dos de los sitios estudiados. Se aislaron 251 cepas de las que se lograron identificar 124 correspondientes a 24 géneros y 40 especies; la más frecuente fue Pseudoalteromonas.

  20. El saque como acción determinante de la clasificación en voley playa femenino

    Directory of Open Access Journals (Sweden)

    G.M. Gea García

    2013-01-01

    Full Text Available El objetivo principal de este estudio fue constatar la importancia del saque como un elemento determinante de la clasificación obtenida por las diferentes parejas durante la competición en voley playa femenino. Para ello se registraron diferentes dimensiones del saque, las cuales quedan divididas en las variables criterio: tipo de saque, técnica de golpeo en el saque y rendimiento del saque. La muestra objeto de estudio estuvo compuesta por un total de 19 parejas. Fueron analizados un total de 15 partidos, dentro de los cuales se registraron 1.100 acciones de saque. Los resultados obtenidos mostraron una diferencia clara de rendimiento en el saque para las parejas participantes en el cruce de variables criterio estudiadas, mostrando el test de Chi cuadrado de Pearson una significación en el cruce de variables criterio estudiadas. Las parejas cuya clasificación fue no finalista tienden a cometer un mayor número de errores, y un porcentaje de puntos directos de saque inferior, que las parejas clasificadas como finalistas y semifinalistas.

  1. Europa's Great Lakes

    Science.gov (United States)

    Schmidt, B. E.; Blankenship, D. D.; Patterson, G. W.; Schenk, P. M.

    2012-04-01

    Unique to the surface of Europa, chaos terrain is diagnostic of the properties and dynamics of its icy shell. While models have suggested that partial melt within a thick shell or melt-through of a thin shell may form chaos, neither model has been able to definitively explain all observations of chaos terrain. However, we present a new model that suggests large melt lenses form within the shell and that water-ice interactions above and within these lenses drive the production of chaos. Our analysis of the geomorphology of Conamara Chaos and Thera Macula, was used to infer and test a four-stage lens-collapse chaos formation model: 1) Thermal plumes of warm, pure ice ascend through the shell melting the impure brittle ice above, producing a lake of briny water and surface down draw due to volume reduction. 2) Surface deflection and driving force from the plume below hydraulically seals the water in place. 3) Extension of the brittle ice lid generates fractures from below, allowing brines to enter and fluidize the ice matrix. 4) As the lens and now brash matrix refreeze, thermal expansion creates domes and raises the chaos feature above the background terrain. This new "lense-collapse" model indicates that chaos features form in the presence of a great deal of liquid water, and that large liquid water bodies exist within 3km of Europa's surface comparable in volume to the North American Great Lakes. The detection of shallow subsurface "lakes" implies that the ice shell is recycling rapidly and that Europa may be currently active. In this presentation, we will explore environments on Europa and their analogs on Earth, from collapsing Antarctic ice shelves to to subglacial volcanos in Iceland. I will present these new analyses, and describe how this new perspective informs the debate about Europa's habitability and future exploration.

  2. Preliminary Results from a Late Pleistocene to Holocene Paleoclimate Study of the Lake Sediment Cores, Northern New Mexico

    Science.gov (United States)

    Cedillo, D. N.; Brister, A. R.; LoPresti, C. A.; Maldonado, M.; Pitrucha, R. M.; West, C.; Martinez, E.; Lineline, J.; Petronis, M. S.

    2011-12-01

    activity, these lacustrian systems shrank to their current condition of minor low-volume isolated lakes and numerous playas and pluvial bodies. We hypothesize that sediments from the LVNWR and surrounding playas contain an invaluable and untapped record of late Pleistocene to Holocene climatic change.

  3. Temporal patterns of glacial lake evolution in high-mountain environments

    Science.gov (United States)

    Mergili, Martin; Emmer, Adam; Viani, Cristina; Huggel, Christian

    2017-04-01

    Lakes forming at the front of retreating glaciers are characteristic features of high-mountain areas in a warming climate. Typically, lakes shift from the proglacial phase (lake is in direct contact with glacier) to a glacier-detached (no direct contact) and finally to a non-glacial phase (lake catchment is completely deglaciated) of lake evolution. Apart from changing glacier-lake interactions, each stage is characterized by particular features of lake growth, and by the lake's susceptibility to sudden drainage (lake outburst flood). While this concept appears to be valid globally, some mountain areas are rich in dynamically evolving proglacial lakes, while in others most lakes have already shifted to the glacier-detached or even non-glacial phase. In the present contribution we (i) explore and quantify the history of glacial lake formation and evolution over the past up to 70 years; (ii) assess the current situation of selected contrasting mountain areas (eastern and western European Alps, southern and northern Pamir, Cordillera Blanca); and (iii) link the patterns of lake evolution to the prevailing topographic and glaciological characteristics in order to improve the understanding of high-mountain geoenvironmental change. In the eastern Alps we identify only very few lakes in the proglacial stage. While many lakes appeared and dynamically evolved until the 1980s between 2550 m and 2800 m asl, most of them have lost glacier contact until the 2000s, whereas very few new proglacial lakes appeared at the same time. Even though a similar trend is observed in the higher western Alps, a more dynamic glacial lake evolution is observed there. The arid southern Pamir is characterized by a high number of proglacial lakes, mainly around 4500 m asl. There is strong evidence that glacial lake evolution is, after a highly dynamic phase between the 1970s and approx. 2000, decelerating. Few proglacial lakes exist in the higher and more humid, heavily glacierized northern Pamir

  4. Repercusión psicosocial del huracán Wilma en la comunidad del consejo popular Miramar, del municipio Playa Psychosocial repercussion caused by Wilma hurricane in the community of Miramar Popular Council of Playa municipality

    Directory of Open Access Journals (Sweden)

    Isis Yvonne Sánchez Gil

    2009-09-01

    Full Text Available Se realizó un estudio descriptivo, observacional y retrospectivo, auxiliándonos de diversas técnicas cuanticualitativas (cuestionario y grupos focales con el propósito de describir las afectaciones más frecuentes sufridas por los vecinos del Consejo Popular Miramar, del municipio Playa, víctimas de la penetración del mar que provocó el huracán Wilma en esta localidad costera, e identificar las fortalezas y debilidades que exhibe esta comunidad para enfrentar las nefastas consecuencias derivadas de eventos de tal naturaleza. Predominaron las afectaciones de orden material, seguidas de los daños a la salud mental, entre los que se destacan: las crisis nerviosas o de ansiedad, el estado de ánimo abatido y los trastornos del sueño. Las fortalezas identificadas fueron la voluntad política del Estado y del Gobierno de la localidad, quienes garantizaron una eficaz estructura organizativa para el enfrentamiento de estas situaciones, la existencia de un mapa de riesgo en el municipio en el que se destacan las zonas más sensibles, la efectividad de los medios masivos de comunicación en la difusión de los partes meteorológicos seguidos por todo nuestro pueblo, y entre las amenazas más notorias, el mal estado de los desagües y de viviendas, así como la pobre percepción de riesgo de la población y la insuficiente preparación de vecinos y líderes comunitarios informales.Authors made a retrospective, observational and descriptive study using different quantitative and qualitative techniques (questionnaire and focal groups to describe the more frequent affectations suffered by neighbors of Miramar Popular Council of Playa municipality, victims of sea penetration caused by Vilma hurricane in this coastal locality, and to identify the strengths and weakness exhibiting this community to confront the awful consequences derived from events like this. There was a predominance of affectation of material order, followed by damages to mental

  5. Bathymetry of Lake Erie and Lake Saint Clair

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Bathymetry of Lake Erie and Lake Saint Clair has been compiled as a component of a NOAA project to rescue Great Lakes lake floor geological and geophysical data and...

  6. Invertebrados asociados al coral constructor de arrecifes Pocillopora damicornis en Playa Blanca, Bahía Culebra, Costa Rica Invertebrates associated with the reef-building coral Pocillopora damicornis at Playa Blanca, Bahía Culebra, Costa Rica

    Directory of Open Access Journals (Sweden)

    Juan José Alvarado

    2012-04-01

    Full Text Available Los arrecifes coralinos son uno de los ecosistemas más diversos en el planeta, tanto por los organismos constructores como por aquellos que viven encima, sobre, dentro y debajo de ellos. Los corales del genero Pocillopora son reconocidos mundialmente por albergar una importante fauna de invertebrados entre sus ramas, los cuales son considerados como simbiontes obligatorios en una gran cantidad de casos. La presente investigación describe la fauna de invertebrados asociados al coral Pocillopora damicornis en Bahía Culebra, Costa Rica, describiendo sus densidades, frecuencias, riquezas y diversidades a través del tiempo. Para esto se colectaron 5 colonias cada 3-4 meses en Playa Blanca, Bahía Culebra. En total se encontraron 448 individuos en 35 especies, siendo Harpiliopsis depressa, Lithophaga aristata, Trapezia ferruginea, Alpheus lottini, Fennera chacei, y Petrolisthes haigae las especies predominantes. Noviembre fue el mes en el que se encontraron los mayores valores en los índices de riqueza, diversidad y diferenciación taxonómica, mientras que agosto fue el que presento los valores más bajos de todos. En términos generales, la época lluviosa mostro mayor riqueza de especies que la época seca. Así mismo, las especies colectados y los valores obtenidos son muy similares a otras zonas del Pacifico Oriental Tropical. Culebra ha venido sufriendo una perdida en la cobertura coralina, que podría tener consecuencias en la diversidad y abundancia de organismos asociados a corales. Estas consecuencias incluyen perdida en la fecundidad de estos organismos, una reducción en su función como limpiadores y protectores de depredadores del coral, poniendo en riesgo su diversidad, lo que puede afectar los stocks de peces depredadores que depende de ellos. Realizar monitoreos permanentes de la criptofauna asociada al coral Pocillopora va a ser determinante para cuantificar perdidas o recuperaciones en la composición de invertebrados asociados

  7. Lake metabolism scales with lake morphometry and catchment conditions

    DEFF Research Database (Denmark)

    Stæhr, Peter A.; Baastrup-Spohr, Lars; Jensen, Kaj Sand

    2012-01-01

    We used a comparative data set for 25 lakes in Denmark sampled during summer to explore the influence of lake morphometry, catchment conditions, light availability and nutrient input on lake metabolism. We found that (1) gross primary production (GPP) and community respiration (R) decline with lake...... in lake morphometry and catchment conditions when comparing metabolic responses of lakes to human impacts....

  8. Locomotor activity of Phalerisida maculata Kulzer (Coleoptera, Tenebrionidae on Chilean sandy beaches Actividad locomotora de Phalerisida maculata Kulzer (Coleoptera, enebrionidae en playas arenosas chilenas

    Directory of Open Access Journals (Sweden)

    EDUARDO JARAMILLO

    2000-03-01

    Full Text Available The locomotor activity of the beetle Phalerisida maculata Kulzer (Coleoptera Tenebrionidae was studied on the surface of the substrate in two sandy beaches of the Chilean coast: one in north central (ca. 29ºS and the other in south central Chile (ca.39ºS. During the summer period of 1991 the circadian locomotor activity was studied in the southern beach, while during that of 1997 in both beaches. To analyze the activity, pitfall traps were used which were ordered along two transects extended between the upper beach and the resurgence zone. The traps were checked (i.e. collection of captured insects every two hours for a total period of 26 hours. The results showed that the adults of P. maculata were mostly active during the night hours, whereas the larvae were active during both, the day and night. Studies carried out in the beach located in south central Chile show that differences in the tidal range (neap vs. spring tides do not affect the activity patterns. During the locomotor activity, adult and larvae move to lower intertidal levels than those usually occupied while buried. Results of laboratory experiments using actographs under conditions of darkness and constant temperature, suggest that adults and larvae of P. maculata presented a circadian rhythm similar to that observed in the field experiments. It is concluded that P. maculata presents a behaviour that appear to be under control of an endogenous rhythm, without showing differences in the circadian rhythm of activity when beaches located at different latitudes are comparedSe estudió la actividad locomotriz del escarabajo Phalerisida maculata Kulzer (Coleoptera, Tenebrionidae sobre la superficie del sustrato de dos playas arenosas de la costa de Chile: una en el centro norte (ca. 29ºS y otra en el centro sur (ca. 39ºS. Durante el período estival de 1991 se estudió la actividad locomotriz circadiana en la playa del centro sur y durante el de 1997 en ambas playas. Para analizar

  9. [Analysis of chemical speciation of heavy metals in L07-11 profile sediments of "Big Ear" Region of Lop Nor Lake].

    Science.gov (United States)

    Zhu, Xin-ping; Zhang, Liang-hui; Jiang, Ping-an; Jia, Hong-tao; Zheng, Chun-xia; Fan, Shun-hui

    2014-12-01

    As playa is the typical characteristic in "Big Ear" Region of Lop Nor Lake, it is significant for enriching playa heavy metal earth environmental chemical data by analyzing species distribution of heavy metal among this district. In this thesis, heavy metal Cd, Pb, Ni, Cu in L07-11 Profile Sediments of "Big Ears" Region of Lop Nor Lake are considered as research objects. Tessier sequential extraction and Graphite furnace atomic absorption method (GF-990) are used to discuss and analyze five forms of Cd, Pb, Ni, Cu among sediments. The results show that the content of Cd, Pb, Ni and Cu is in the range from 1.10~2.54, 9.18~20.02, 9.88~17.15, 4.43~21.11 mg · kg(-1), respectively. The value of organic matter range from 8.71-54.72 g · kg(-1). The order of the bioavailable state in heavy metals is Cd>Pb>Cu>Ni. Pb and Cd mainly exist in exchangeable form including water-soluble, and that Ni is in residual form, and that Cu is mostly in Fe-Mn oxide bound iron-manganese oxides or in residual form. Among surface sediments, effective content of heavy metal is more than 80%. Except Cu, the content of heavy metal Cd, Pb, Ni in exchangeable form is more than 60%. Heavy metal Cd and Pb has higher secondary release potential. The content of heavy metal and organic material has some correlation.

  10. Intersectoral coordination, community empowerment and dengue prevention: six years of controlled interventions in Playa Municipality, Havana, Cuba.

    Science.gov (United States)

    Sanchez, L; Perez, D; Cruz, G; Castro, M; Kourí, G; Shkedy, Z; Vanlerberghe, V; Van der Stuyft, P

    2009-11-01

    To document the process, outcome and effectiveness of a community-based intervention for dengue control. The primary intervention, focused on strengthening intersectoral coordination, was initiated by researchers in January 2000 in a pilot area in Playa municipality, Havana. In August 2002 health authorities extended the intervention to neighbouring areas, one of which was selected for evaluation. In August 2003 a complementary strategy, focused on community empowerment, was initiated in half of the pilot area. In our control area, routine dengue activities continued throughout the study period. Longitudinal process assessment was carried out using document analysis, interviews and group discussions. Random population surveys in 1999, 2002 and 2005 assessed levels of participation and behavioural changes. Entomological surveillance data from 1999 to 2005 were used to determine effectiveness. Mean scores for participation in the pilot area were 1.6, 3.4 and 4.4 at baseline, and 2 years after initiating intersectoral coordination and intersectoral coordination plus community empowerment interventions, respectively. While in the control area little behavioural change was observed over time, changes were considerable in the pilot and extension areas, with 80% of households involved in the community empowerment intervention showed adequate behavioural patterns. The pilot and extension areas attained comparable entomological effectiveness with significantly lower Breteau indices (BIs) than the control area. The pilot (sub-) area with the community empowerment intervention reached BIs below 0.1 that continued to be significantly lower than the one in the control area until the end of the study. The study showed a trend in the levels and quality of participation, behavioural change and effectiveness of Aedes control from the routine activities only over an intervention with intersectoral coordination to one that combined intersectoral coordination and community empowerment

  11. Septic tanks as larval habitats for the mosquitoes Aedes aegypti and Culex quinquefasciatus in Playa-Playita, Puerto Rico.

    Science.gov (United States)

    Burke, R; Barrera, R; Lewis, M; Kluchinsky, T; Claborn, D

    2010-06-01

    Adult Aedes aegypti (Linnaeus) (Diptera: Culicidae) were previously recovered from emergence traps on septic tanks in southeastern Puerto Rico. In this study we quantified immature mosquito abundance and its relationship with structural variables of the septic tanks and chemical properties of the water containing raw sewage. A miniaturized floating funnel trap was used to sample 89 septic tanks for larvae in the Puerto Rican community of Playa-Playita. Aedes aegypti larvae were recovered from 18% of the sampled tanks (10.3 larvae per septic tank per day). Larval presence was positively associated with cracking of the septic tank walls and uncovered access ports. Larval abundance was positively associated with cracking of the septic tank walls and larger tank surface areas, and inversely associated with the total dissolved solids (TDS). Culex quinquefasciatus (Say) larvae were also recovered from 74% of the septic tanks (129.6 larvae per septic tank per day). Larval presence was negatively associated with TDS in the water and larval abundance was positively associated with cracking of the septic tank walls. A screened, plastic emergence trap was used to sample 93 septic tanks within the community for Ae. aegypti and Cx. quinquefasciatus adults. Aedes aegypti adults were recovered from 49% of the sampled tanks (8.7 adults per septic tank per day) and Cx. quinquefasciatus adults were recovered from 97% of the sampled tanks (155.5 adults per septic tank per day). Aedes aegypti adult presence was positively associated with cracking, uncapped openings and septic water pH. The Ae. aegypti adult counts were positively associated with cracking and inversely associated with TDS and conductivity. This study marks the first published record of the recovery of Ae. aegypti larvae from holding tanks containing raw sewage in the Caribbean region. Our study indicates that Ae. aegypti larvae are present in sewage water and that septic tanks have at least the potential to maintain

  12. [Distribution patterns and bioerosion of the sea urchin Centrostephanus coronatus (Diadematoida: Diadematidae), at the reef of Playa Blanca, Colombian Pacific].

    Science.gov (United States)

    Toro-Farmer, Gerardo; Cantera, Jaime R; Londoño-Cruz, Edgardo; Orozco, Carlos; Neira, Raul

    2004-03-01

    Regular sea-urchins are one of the main bioeroding organisms affecting coral reefs around the world. The abundance, distribution and bioerosion rate of the sea-urchin Centrostephanus coronatus, were determined in different reef zones of Playa Blanca fringing reef (Gorgona Island, Colombian pacific coast) during 1997 and 1998. The erosion rates were determined calcinating the gut content of the sea-urchins to eliminate all organic components and preserve the inorganic portion of calcium carbonate. C. coronatus showed the highest densities towards the central zones of the reef (plain-crest and front) (12.4 ind/m2; range 0-48 ind/m2). The highest mean bioerosion rate was 0.103 kgCaCO3/m2/yr in the reef plain-crest (0-0.69 kgCaCO3/m2/yr). In the other zones, (back reef and reef front) the mean bioerosion rates were 0.071 (range 0-0.39) and 0.052 (range 0-0.31) kgCaCO3/m2/yr respectively. According to the present data, it can be seen that the destruction of coralline skeletons, produced in this reef by sea-urchins is rather low, compared with the abrasion caused by these organisms in other places of the world. However, the combined action of C. coronatus and other bioeroding organisms (borers and grazers). along with some adverse environmental factors to corals, can be causing a negative balance between normal processes of reef accretion-destruction in Gorgona Island reefs.

  13. COMPETITIVIDAD Y CALIDAD EN LOS DESTINOS TURÍSTICOS DE SOL Y PLAYA. EL CASO DE LAS ISLAS CANARIAS

    Directory of Open Access Journals (Sweden)

    J. Rosa Marrero Rodríguez

    2008-01-01

    Full Text Available El objeto del artículo es conocer y comparar el nivel de competitividad que presentan las cuatro islas turísticas canarias más importantes, a través de la combinación de diferentes variables de aproximación al mismo. Todo ello se plantea en el contexto más general de discusión de los mecanismos de reconversión y reposicionamiento en los destinos tradicionales de sol y playa a través de la implementación de elementos de calidad en el negocio turístico. Para acercarnos a la medición de la competitividad se ha usado una metodología doble: a través de las estadísticas del gasto turístico, los niveles de ocupación y la evolución del número de plazas y de turistas. Y también a través de un pequeño estudio de casos en Internet, donde se han analizado los precios para dos paquetes turísticos característicos. Los resultados coinciden en indicar que, a pesar de la estrategia de calidad adoptada por Lanzarote, esto no parece traducirse en una mayor rentabilidad económica para el sector. En definitiva, a pesar de la proclamada importancia de la calidad como factor clave de competitividad, no está claro que el mercado esté dispuesto a recompensar a aquellos destinos que apuestan con precios mayores por la calidad.

  14. Cancer Staging

    Science.gov (United States)

    ... the tumor is to grow and spread The TNM Staging System The TNM system is the most widely used cancer staging system. Most hospitals and medical centers use the TNM system as their main method for cancer reporting. ...

  15. Efectividad del monitoreo de la anidación de tortugas marinas para determinar el éxito reproductivo en playas del sur de Cuba

    Directory of Open Access Journals (Sweden)

    Julia Azanza-Ricardo

    2015-07-01

    Full Text Available El monitoreo de las anidaciones es muy útil como herramienta para la conservación pero el esfuerzo de trabajo en diferentes áreas puede variar grandemente. En Cuba, se aplican cuatro enfoques diferentes: monitoreo sistemático nocturno y diurno (MSN, y monitoreo esporádico con o sin comprobación de nidos (MECC. La cantidad y exactitud de los datos tomados y la calidad de la información derivada de ellos difieren. Por esta razón, en el presente trabajo se evalúa la efectividad de cada enfoque para determinar el éxito reproductivo de tortugas marinas en Cuba. El MSN sólo se realiza en las playas de anidación de la Península de Guanahacabibes, mientras que el MECC es el más extendido en el país. La porción de la temporada de anidación de cada una de las tres especies que anidan en Cuba (Chelonia mydas, Caretta caretta y Eretmochelys imbricata que se cubre con personal de monitoreo es baja para la mayoría de las playas, y sobre todo en el caso de E. imbricata. Se detectaron diferencias entre el monitoreo sistemático y esporádico, por tanto, la capacidad de detectar rastros falsos y verdaderos depende esencialmente de la frecuencia de monitoreo. Esto afecta la capacidad para evaluar el éxito de la anidación por playas. A pesar del incremento en los esfuerzos realizados en Cuba para el seguimiento de las principales colonias de anidación, se deben identificar nuevas estrategias para garantizar la correcta toma de información, y una mayor eficiencia del programa de monitoreo para obtener la mayor información posible de cada una de las especies con un adecuado balance de costo-beneficio.

  16. Distribución espacial de Ocypode quadrata (Decapoda: Ocypodidae en ocho playas de la zona norte oriental de Cuba

    Directory of Open Access Journals (Sweden)

    Frank A. Ocaña

    2012-09-01

    Full Text Available Uno de los organismos más comunes en las playas arenosas son los miembros del género Ocypode conocidos como cangrejos fantasmas, están ampliamente distribuidos en las regiones tropicales y subtropicales; además tienen un importante papel en la transferencia de energía en diferentes niveles tróficos. El objetivo del presente trabajo es dar a conocer aspectos relacionados con la variación espacial de la densidad de O. quadrata en playas con diferente nivel de influencia humana en la costa norte oriental de Cuba. En mayo de 2010, fueron contadas un total de 355 galerías en 360 unidades de muestreo. La composición por clases de tallas fue de 237 galerías de jóvenes y 118 de adultos. Del total de galerías contadas el 74% ocuparon el nivel P1, 20% el nivel P2 y 6% el nivel P3. La densidad varió entre 0.06-0.52galerías/m2. A pesar del nivel de influencia humana, la mayoría de las playas no mostró diferencias significativas en la densidad de galerías (Scheffé, p>0.05. La densidad de individuos en la zona superior de resaca del oleaje es mayor (Scheffé, pSpatial distribution of Ocypode quadrata (Decapoda: Ocypodidae in eight beaches of NorthEastern Cuba. Studies on the ecology of Ocypode quadrata have been mostly carried out in the Northern and Southern part of its distribution range. In despite that this species is common in Cuban beaches, there are no quantitative studies regarding its abundance and spatial distribution. The aim of this study was to report some aspects about the spatial variation of O. quadrata density in sandy beaches, with different levels of human influence, in the North coast of Eastern Cuba. For this, on May 2010, eight beaches with different levels of human influence were surveyed. On each beach, the number of crabs burrows were counted in 45 quadrats of 4m2 located in three different strata (P1, P2 and P3. According to burrow opening diameter, crabs were separated into young and adults forms. To determine the

  17. Application of a combined measurement and modeling method to quantify windblown dust emissions from the exposed playa at Mono Lake, California.

    Science.gov (United States)

    Ono, Duane; Kiddoo, Phill; Howard, Christopher; Davis, Guy; Richmond, Kenneth

    2011-10-01

    Particulate matter network of 25 Cox sand catchers (CSCs) was used to measure the mass of saltating particles to estimate sand flux rates across a 2-km2 area. Two electronic sensors (Sensits) were used to time-resolve the CSC sand mass to estimate hourly sand flux rates, and a perimeter tapered element oscillating microbalance (TEOM) monitor measured hourly PM10 concentrations. Hourly sand flux rates were related by dispersion modeling to hourly PM10 concentrations to back-calculate the ratio of vertical PM10 flux to horizontal sand flux (K-factors). Geometric mean K-factor values (K(f)) were found to change seasonally, ranging from 1.3 x 10(-5) to 5.1 x 10(-5) for sand flux measured at 15 cm above the surface (q15). Hourly PM10 emissions, F, were calculated by applying seasonal K-factors to sand flux measurements (F = K(f) x q15). The maximum hourly PM10 emission rate from the study area was 76 g/m2 x hr (10-m wind speed = 23.5 m/sec). Maximum daily PM10 emissions were estimated at 450 g/m2 x day, and annual emissions at 1095 g/m2 x yr. Hourly PM10 emissions were used by the U.S. Environmental Protection Agency (EPA) guideline AERMOD dispersion model to estimate downwind ambient impacts. Model predictions compared well with monitor concentrations, with hourly PM10 ranging from 16 to over 60,000 microg/m3 (slope = 0.89, R2 = 0.77).

  18. ¿Puerto o playa? Un análisis económico del conflicto entre la ciudad de Trujillo y el puerto de Salaverry

    OpenAIRE

    Enzo Defilippi Angeldonis

    2013-01-01

    Síntesis Salaverry es un pequeño puerto localizado a pocos kilómetros de la ciudad de Trujillo, al norte del Perú. Moviliza alrededor de 2.5 millones de toneladas de carga al año, en su mayoría, granel seco. Desde 1982, ENAPU, la empresa estatal que opera el puerto, ha venido reduciendo sus costos de dragado mediante el alargamiento de un molón retenedor de arena, solución que ha alterado el equilibrio dinámico de la costa y causado la virtual desaparición de las playas de Trujillo. Desde el ...

  19. Uso de colifagos somáticos como indicadores de contaminación fecal en playas de “la Costa Verde”, Lima–Perú

    Directory of Open Access Journals (Sweden)

    Hinsby Cadillo Quiroz

    2014-06-01

    Full Text Available El presente estudio fue realizado con el objetivo de evaluar el uso de los colifagos somáticos como indicadores de contaminación fecal en aguas recreacionales marinas. Los colifagos somáticos fueron cuantificados en 140 muestras provenientes de 5 playas del circuito de la “Costa Verde”, Lima, y correlacionados con los indicadores de contaminación fecal convencionales (Coliformes fecales, E. coli y Enterococos. Los colifagos fueron determinados por el método de “capa simple” previa aplicación de la técnica modificada de “filtración de la muestra” y utilizando a E. coli ATCC 13706 como cepa hospedero. Los Coliformes fecales (CF, E. coli (EC y Enterococos (EN fueron cuantificados por el método del Número Más Probable (NMP. Para efectos de análisis estadístico se consideró niveles de contaminación fecal en función de valores arbitrarios de <1000 CF/100 mL (“baja contaminación” y >1000 CF/100 mL (“alta contaminación”. Las playas evaluadas presentaron niveles de contaminación fecal de <3 a 2,4 x 105 CF y EC y <3 a 2,4 x 104 EN. En las muestras con “baja contaminación” fecal, el 32% de los recuentos de los colifagos fueron mayores que los de CF y EC; miemtras que en las muestras con “alta contaminación” ningún recuento de colifagos superó a los de CF o EC. Por otro lado, de acuerdo al análisis estadístico de componentes principales los colifagos y Enterococos fueron los mejores indicadores de contaminación fecal en las playas evaluadas. Asimismo, se determinó correlaciones estadísticamente significativas entre colifagos, CF y EC; siendo mayor en muestras con alta contaminación (r = 0,89 que en aquellas con baja contaminación (r = 0,43. Mediante la cuantificación de colifagos en las muestras evaluadas se determinó estadísticamente el valor de 115 UFP/100 mL como criterio calificativo de balneabilidad para las playas de la zona evaluada. De acuerdo a nuestros resultados los colifagos som

  20. Lista sistemática de Algas y Fanerógamas de Playa Yuraguanal, Provincia Holguín, Cuba.

    Directory of Open Access Journals (Sweden)

    Antonio Vega Torres

    2009-01-01

    Full Text Available Se presenta la lista sistemática de algas y fanerógamas de Playa Yuraguanal, provincia Holguín. Los muestreos se realizaron durante el año 2005, en tres biotopos: seibadal, plano rocoso y arrecife trasero, en época de seca y lluvia. Se determinaron 79 especies de macroalgas y 3 fanerógamas. Entre las algas, 30 pertenecen al Phylum Rhodophyta, 18 a Ochrophyta y 31 a Chlorophyta. Las fanerógamas fueron Thalassia testudinum Banks & Solander, Syringodium filiforme Kutzing y Halodule wrightii den Hartog.

  1. Geomorfologia Costera y Explotación de Arena de Playa en la Provincia de Buenos Aires y sus Consecuencias Ambientales

    Directory of Open Access Journals (Sweden)

    Silvia C. Marcomini

    2006-12-01

    Full Text Available El present trabajo tiene como objetivo principal caracterizar el medio físico de las áreas costeras, con el fin determinar los impactos en la hidrodinámica litoral, a mediano y corto plazo, generado por la explotación de arena de playa en las principales localidades costeras de la provincia de Buenos Aires, entre cabo San Antonio y Necochea. Para tal fin se describen las explotaciones mineras de mayor magnitud llevadas a cabo a lo largo de la costa de la provincia de Buenos Aires y se analiza su efecto para cada morfología costera. En todos los casos las explotaciones han ocasionado un deficit de arena en la corriente de deriva litoral, lo que hace que la erosión se traslade como una onda en el sentido de la deriva litoral, es decir hacia el norte para estas costas. El tipo de costa que recibe el impacto de esta onda condiciona el grado de erosión a la que este sujeta. En costas acantiladas cohesivas las explotaciones han producido un importante incremento en las tasas de retroceso de los acantilados y pérdida de playa. En costas definidas como de tipo B (con desarrollo de bermas los efectos erosivos de la explotacíon, sumados a otros factores antrópicos, han afectado fundamentalmente las morfologías de playa, mientras que en las de tipo A (sin desarrollo de bermas, el efecto no solo ha alcanzado la playa sino que también ha provocado retoceso de la línea de costa. Asimismo de determinó que las tasas de retroceso de la costa se aceleran o retardan en igual medida durante la explotación y recuperación respectivamente; es decir que la recuperación por interrupción de las actividades mineras es semejante en magnitud a la erosión inducida durante la explotación.

  2. Uso de colifagos somáticos como indicadores de contaminación fecal en playas de “la Costa Verde”, Lima–Perú

    OpenAIRE

    Hinsby Cadillo Quiroz; Jorge León Quispe

    2014-01-01

    El presente estudio fue realizado con el objetivo de evaluar el uso de los colifagos somáticos como indicadores de contaminación fecal en aguas recreacionales marinas. Los colifagos somáticos fueron cuantificados en 140 muestras provenientes de 5 playas del circuito de la “Costa Verde”, Lima, y correlacionados con los indicadores de contaminación fecal convencionales (Coliformes fecales, E. coli y Enterococos). Los colifagos fueron determinados por el método de “capa simple” previa aplicaci...

  3. Contaminación de playas turísticas de la ciudad de Cartagena de Indias con parásitos de importancia sanitaria 2012-2014

    OpenAIRE

    Morales Aleans, Marina; Esquivia Muñoz, Venancio

    2015-01-01

    Tesis (Máster en Microbiología Clínica).-- Universidad de San Buenaventura, Facultad Ciencias de la Salud, 2014 Las playas turísticas están sometidas a un constante estrés ambiental, dado principalmente por las descargas no controladas de desagües domésticos e industriales no tratados, por el contacto directo con la materia fecal de animales terrestres y la mala disposición de residuos sólidos por parte de la población humana que hace parte de su entorno en calidad de habitantes residentes...

  4. Estudio de los hábitos deportivos de los estudiantes de la Universidad de Playa Ancha Valparaíso-Chile

    OpenAIRE

    Fernández Uribe, Sergio

    2013-01-01

    [Resumen] Este estudio se enmarca en una importante línea de investigación sociodeportiva y, entre las temáticas de los hábitos deportivos, la de los estudiantes universitarios. Así pues, el objetivo de esta investigación fue determinar los hábitos físico-deportivos de los estudiantes de la Universidad de Playa Ancha, Valparaíso - Chile, entendido éste como un intento inicial de conocer la situación real, como paso previo para llevar a cabo las modificaciones oportunas que sean necesa...

  5. Alternativas para la recuperación y mantenimiento de playas, su relación con la educación ambiental. Varadero, una experiencia.

    OpenAIRE

    2010-01-01

    Varadero, por su parte, no está exento del paulatino deterioro que ha ido sufriendo la playa debido a causas naturales y antrópicas, por lo que se ha decidido poner en práctica un plan de medidas para proteger su entorno. Con este fin y basándose en los estudios realizados por el Instituto de Oceanología fundamentalmente, la Delegación Territorial del CITMA en Matanzas en coordinación con el Ministerio del Turismo, han llevado a cabo la ejecuci...

  6. Aplicación de directrices de calidad para la gestión y uso turístico de balnearios y playas

    OpenAIRE

    Claudia Toselli; Arturo Fabián Godoy

    2011-01-01

    La aplicación de estándares de calidad es hoy un tema prioritario en las agendas del turismo internacional. Particularmente, en los últimos años, se ha dedicado mucho esfuerzo al establecimiento de códigos, criterios y sistemas de certificación turística para orientar tanto a los operadores turísticos y los actores locales, como a los propios turistas. En Argentina, ante la necesidad de abocarse a la mejora de la calidad ambiental y turística de la prestación de servicios en playas, los organ...

  7. Floodplain Lakes: Evolution and Response

    Science.gov (United States)

    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.

  8. DNR 24K Lakes

    Data.gov (United States)

    Minnesota Department of Natural Resources — Medium scale lake polygons derived from the National Wetlands Inventory (NWI) polygons and MnDOT Basemap lake delineations. Integrated with the DNR 24K Streams...

  9. Lake trout rehabilitation in Lake Ontario

    Science.gov (United States)

    Elrod, Joseph H.; O'Gorman, Robert; Schneider, Clifford P.; Eckert, Thomas H.; Schaner, Ted; Bowlby, James N.; Schleen, Larry P.

    1995-01-01

    Attempts to maintain the native lake trout (Salvelinus namaycush) population in Lake Ontario by stocking fry failed and the species was extirpated by the 1950s. Hatchery fish stocked in the 1960s did not live to maturity because of sea lamprey (Petromyzon marinus) predation and incidental commercial harvest. Suppression of sea lampreys began with larvicide treatments of Lake Ontario tributaries in 1971 and was enhanced when the tributaries of Oneida Lake and Lake Erie were treated in the 1980s. Annual stocking of hatchery fish was resumed with the 1972 year class and peaked at about 1.8 million yearlings and 0.3 million fingerlings from the 1985–1990 year classes. Survival of stocked yearlings declined over 50% in the 1980 s and was negatively correlated with the abundance of lake trout > 550 mm long (r = −0.91, P < 0.01, n = 12). A slot length limit imposed by the State of New York for the 1988 fishing season reduced angler harvest. Angler harvest in Canadian waters was 3 times higher in eastern Lake Ontario than in western Lake Ontario. For the 1977–1984 year classes, mean annual survival rate of lake trout age 6 and older was 0.45 (range: 0.35–0.56). In U.S. waters during 1985–1992, the total number of lake trout harvested by anglers was about 2.4 times greater than that killed by sea lampreys. The number of unmarked lake trout < 250 mm long in trawl catches in 1978–1992 was not different from that expected due to loss of marks and failure to apply marks at the hatchery, and suggested that recruitment of naturally-produced fish was nil. However, many of the obstacles which may have impeded lake trout rehabilitation in Lake Ontario during the 1980s are slowly being removed, and there are signs of a general ecosystem recovery. Significant recruitment of naturally produced lake trout by the year 2000, one interim objective of the rehabilitation plan for the Lake, may be achieved.

  10. Entendiendo, Evaluando y Solucionando los Problemas de Contaminación de Luz en Playas de Anidamiento de Tortugas Marinas/Understanding, assessing, and resolving light- pollution problems on sea turtle nesting beaches

    OpenAIRE

    Witherington, Blair E.; Martin, R. Erik

    2003-01-01

    Mantener al público informado sobre los problemas de la contaminación con luz de las playas de anidamiento de tortugas es un paso fundamental para oscurecer las playas de tortugas marinas. Muchas de aquellas personas responsables de esta iluminación no tienen conocimiento del efecto negativo que esto ocasiona y están dispuestos a corregir el problema voluntariamente una vez que son informados. Sin embargo, a menudo es necesaria legislación para un mayor control de la i...

  11. Statistical analysis of interaction between lake seepage rates and groundwater and lake levels

    Science.gov (United States)

    Ala-aho, P.; Rossi, P. M.; Klöve, B.

    2012-04-01

    In Finland, the main sources of groundwater are the esker deposits from the last ice age. Small lakes imbedded in the aquifer with no outlets or inlets are typically found in eskers. Some lakes at Rokua esker, in Northern Finland, have been suffering from changes in water stage and quality. A possible permanent decline of water level has raised considerable concern as the area is also used for recreation and tourism. Rare biotypes supported by the oligotrophic lakes can also be endangered by the level decline. Drainage of peatlands located in the discharge zone of the aquifer is a possible threat for the lakes and the whole aquifer. Drainage can potentially lower the aquifer water table which can have an effect on the groundwater-lake interaction. The aim of this study was to understand in more detail the interaction of the aquifer and the lake systems so potential causes for the lake level variations could be better understood and managed. In-depth understanding of hydrogeological system provides foundation to study the nutrient input to lakes affecting lake ecosystems. A small lake imbedded the Rokua esker aquifer was studied in detail. Direct measurements of seepage rate between the lake and the aquifer were carried out using seepage meters. Seepage was measured from six locations for eight times during May 2010 - November 2010. Precipitation was recorded with a tipping bucket rain gauge adjacent to the lake. Lake stage and groundwater levels from three piezometers were registered on an hourly interval using pressure probes. Statistical methods were applied to examine relationship between seepage measurements and levels of lake and groundwater and amount of precipitation. Distinct areas of inseepage and outseepage of the lake were distinguished with seepage meter measurements. Seepage rates showed only little variation within individual measurement locations. Nevertheless analysis revealed statistically significant correlation of seepage rate variation in four

  12. LAKE VICTORIA BASIN

    African Journals Online (AJOL)

    selected satellite lakes and Mara River in Lake Victoria basin, during wet and dry seasons in. 2002. Samples ... The wet season recorded higher biomass in all satellite lakes than during the dry season (t = 2.476, DF ..... communication. Urbana ...

  13. Well staged

    Energy Technology Data Exchange (ETDEWEB)

    Budd, Godfrey

    2011-06-15

    Packers Plus Energy Services Inc. has commercially launched QuickFRAC, a multi-stage completition system which can fracture four to five isolated stages in one treatment and set up a record of 23-stage slickwater frac in less than 10 hours. It could take up to 40 days to do 100 fracture treatments with other systems. This technology makes it possible to distribute fluid at each port thanks to the limited entry system. In order to make multiple isolated stages within one treatment zone, each zone includes multiple QuickPORT sleeves with packers on either side. The other technology which made this possible is the repeater port system, it allows them to perform more frac stages. This technology could be useful in the future since the need for stages will be doubling soon with microdarcy shale oil extraction which is more difficult than gas.

  14. The microbiological activity and toxicity of oil-polluted playa solonchaks and filled grounds within the Severnye Buzachi Oil Field (Kazakhstan)

    Science.gov (United States)

    Tynybaeva, T. G.; Kostina, N. V.; Terekhov, A. M.; Kurakov, A. V.

    2008-10-01

    The number of colony-forming units of microorganisms, the viable biomass, and also the intensity of the microbiological processes (respiration, nitrogen fixation, denitrification, and cellulose decomposition) in playa solonchaks and sandy-loamy filled grounds in the territory of the Severnye Buzachi Oilfields (Kazakhstan) were much lower than in other soil types attesting to the limited capability of these substrates for selfpurification. Upon pollution by oil at concentrations of 100 600 mg/kg, the number of copiotrophic bacteria increased, whereas the actinomycetal and fungal populations were reduced and the biomass pool, the rates of CO2 emission, the potential nitrogen fixation, and denitrification became higher. The microbial communities of the playa solonchaks were weakly active and consumed few applied substrates. The biotesting with Artemia salina L. showed that some areas belonged to the lands of the 4th danger class, although the majority of the soil and substrate samples were not toxic. The germination of Lepidium sativum L. seeds was suppressed because of the salt toxicity, which is not related to the oil concentration (30 to 600 mg/kg).

  15. Percepción de seguridad del turismo extranjero que arriba en casas rodantes a Playas de Mazatlán (Sinaloa

    Directory of Open Access Journals (Sweden)

    Silvestre Flores Gamboa

    2016-12-01

    Full Text Available El presente artículo recoge la percepción de seguridad que tienen los visitantes que viajan en casas rodantes y se hospedan en establecimientos conocidos como trailer parks en las playas del puerto de Mazatlán, principal destino turístico en el estado de Sinaloa (México. Además, se recopila información sociodemográfica y económica de los respondientes por medio de la aplicación de un cuestionario como instrumento de recolección de datos. Así mismo, se realizan correlaciones para demostrar la asociación entre quienes cambian sus planes de viajes en respuesta a las advertencias realizadas por el gobierno del país de origen, sean estos de EE. UU. y/o de Canadá. Entre los resultados es posible identificar la estadía y el gasto promedio diario y mensual, también elementos que inciden en su decisión de viaje. Finalmente, se analiza el papel que juega la seguridad en algunos sitios de atracción turística dentro del destino, así como en los servicios de transporte, sus playas e impresiones acerca de las alertas de viaje que emiten autoridades de Gobierno estadounidenses y canadienses.

  16. DISEÑO DE UNA PROPUESTA DE MARKETING ECOTURÍSTICO PARA EL MUNICIPIO DE LA PLAYA DE BELÉN COMO DESTINO TURÍSTICO

    Directory of Open Access Journals (Sweden)

    Luis Alfonso Sánchez Borja

    2014-06-01

    Full Text Available El proyecto tiene como objetivo diseñar una propuesta de Marketing Ecoturístico para el Municipio de la Playa de Belén en el departamento de Norte de Santander, Colombia; se presentan los aspectos generales del Municipio, tales como; ubicación geográfica, topografía, aspectos étnicos y culturales. Seguidamente describe el análisis DOFA, la metodología y conceptos utilizados de mayor interés que aportan al desarrollo de la investigación con el fin de realizar un diagnóstico turístico sobre los componentes de intangibilidad turística, superestructura, infraestructura, planta turística, atractivos y descripción cultural de la comunidad de la Playa de Belén. Los resultados obtenidos se reflejan a través del análisis de mercado mediante encuesta aplicada a la comunidad, operadores y turistas, se analiza la situación actual, se diseña el plan de marketing creando unos objetivos, estrategias y recomendaciones de proyección para el municipio.

  17. Trading stages

    DEFF Research Database (Denmark)

    Steiner, Uli; Tuljapurkar, Shripad; Coulson, Tim

    2012-01-01

    Interest in stage-and age structured models has recently increased because they can describe quantitative traits such as size that are left out of age-only demography. Available methods for the analysis of effects of vital rates on lifespan in stage-structured models have not been widely applied ...... examples. Much of our approach relies on trading of time and mortality risk in one stage for time and risk in others. Our approach contributes to the new framework of the study of age- and stage-structured biodemography....

  18. La atención de urgencia y la dispensarización en el Policlínico Universitario Docente de Playa The urgency care and dispensarization in the Playa Teaching and University Polyclinic

    Directory of Open Access Journals (Sweden)

    Leonardo Antonio Cuesta Mejías

    2011-09-01

    Full Text Available INTRODUCCIÓN: Un grupo importante de pacientes dispensarizados por enfermedades crónicas priorizadas, asisten con frecuencia a nuestros servicios de urgencia y generalmente no presentan verdaderas urgencias. La dispensarización en nuestra área de salud tiene un grupo importante de insuficiencias. Esta situación determina la asistencia de muchos de los pacientes a estos servicios en busca de la atención no satisfecha a nivel de los consultorios del médico y la enfermera de la familia. OBJETIVOS: Caracterizar la situación de la atención de urgencias en general, y la atención de urgencias a pacientes con enfermedades crónicas no transmisibles en particular, en el Policlínico Universitario Docente de Playa. MÉTODOS: Se realizó un estudio descriptivo de corte transversal, mediante la revisión documental de las hojas de actividades del servicio de urgencias, de los meses de octubre, noviembre y diciembre del 2006 y de enero, febrero y marzo del 2007. Las principales variables estudiadas fueron: cantidad de pacientes en general atendidos en este servicio, pacientes que fueron atendidos por enfermedades priorizadas dentro de la dispensarización, pacientes que asistieron por una verdadera descompensación de su enfermedad, y especialmente los que tuvieron necesidad de ser ingresados en nuestra sala de observación por algunas de estas afecciones. Estos últimos fueron registrados y se revisaron sus historias clínicas, así como las hojas de actividades diarias de sus médicos de familia, de los 3 días posteriores a su ingreso. RESULTADOS: La mayoría de los pacientes que acuden a nuestros servicios de urgencias son adultos, de ellos alrededor del 15 % lo hace debido a una enfermedad crónica, la inmensa mayoría de estos por asma bronquial e hipertensión arterial (más del 97 %. Solamente el 1,1 % de los pacientes que se consultaron por alguna enfermedad crónica, requirió de ingreso en la sala de observación por descompensación de

  19. La experiencia de la guerra en la pantalla: El desembarco en la playa de Omaha de Saving Private Ryan

    Directory of Open Access Journals (Sweden)

    Julio Montero-Díaz

    2015-01-01

    Full Text Available El cine de Hollywood ha dado un testimonio informal de las guerras, particularmente de la Segunda Guerra Mundial. Saving Private Ryan (Steven Spielberg, 1998 rompió el modelo naturalista y romántico del subgénero. Se basó en el testimonio de los veteranos de guerra y se orientó no hacia el desarrollo de una operación bélica, sino a la reproducción hiperrealista del combate y la cotidianidad de la guerra. Dio forma audiovisual a una memoria y experiencia individuales, las del veterano, que habitualmente no habían tenido cabida en el relato institucional de la guerra o en su reflejo cinematográfico anterior. Este artículo presenta un análisis estilístico de su secuencia más aplaudida por su efecto y valor artístico: el desembarco en la playa de Omaha. Atiende a la descripción de sus recursos de planificación, sonido y montaje. Muestra que, a través del recurso a técnicas estilísticas expresivas formuladas por S. M. Eisenstein, la secuencia busca introducir al espectador en el combate, hacerle participar de las sensaciones y razonamientos del soldado –en este caso el capitán Miller–, y lograr así su inmersión en la acción bélica, su compromiso con él y la comprensión del origen de su trauma. Para ello se ha recurrido a una vía de análisis inspirada en el proceso metodológico que S. M. Eisenstein empleaba en dos de sus artículos para explicar el valor del planteamiento estilístico de El acorazado Potemkin (1925 a sus detractores. Consiste en la descripción del esquema expresivo que configura el diseño de planos y fragmentos de montaje y su comparación con los que los preceden o suceden. Mediante esta metodología dialéctica, se describe el estilo general de la secuencia y sus pretensiones expresivas, así como se localizan momentos de contraste y ruptura que acusan su servicio a un motivo emocional: traducir el trauma del combatiente.

  20. Invertebrados asociados al coral constructor de arrecifes Pocillopora damicornis en Playa Blanca, Bahía Culebra, Costa Rica

    Directory of Open Access Journals (Sweden)

    Juan José Alvarado

    2012-04-01

    Full Text Available Los arrecifes coralinos son uno de los ecosistemas más diversos en el planeta, tanto por los organismos constructores como por aquellos que viven encima, sobre, dentro y debajo de ellos. Los corales del genero Pocillopora son reconocidos mundialmente por albergar una importante fauna de invertebrados entre sus ramas, los cuales son considerados como simbiontes obligatorios en una gran cantidad de casos. La presente investigación describe la fauna de invertebrados asociados al coral Pocillopora damicornis en Bahía Culebra, Costa Rica, describiendo sus densidades, frecuencias, riquezas y diversidades a través del tiempo. Para esto se colectaron 5 colonias cada 3-4 meses en Playa Blanca, Bahía Culebra. En total se encontraron 448 individuos en 35 especies, siendo Harpiliopsis depressa, Lithophaga aristata, Trapezia ferruginea, Alpheus lottini, Fennera chacei, y Petrolisthes haigae las especies predominantes. Noviembre fue el mes en el que se encontraron los mayores valores en los índices de riqueza, diversidad y diferenciación taxonómica, mientras que agosto fue el que presento los valores más bajos de todos. En términos generales, la época lluviosa mostro mayor riqueza de especies que la época seca. Así mismo, las especies colectados y los valores obtenidos son muy similares a otras zonas del Pacifico Oriental Tropical. Culebra ha venido sufriendo una perdida en la cobertura coralina, que podría tener consecuencias en la diversidad y abundancia de organismos asociados a corales. Estas consecuencias incluyen perdida en la fecundidad de estos organismos, una reducción en su función como limpiadores y protectores de depredadores del coral, poniendo en riesgo su diversidad, lo que puede afectar los stocks de peces depredadores que depende de ellos. Realizar monitoreos permanentes de la criptofauna asociada al coral Pocillopora va a ser determinante para cuantificar perdidas o recuperaciones en la composición de invertebrados asociados

  1. Historical trophic evolutions and their ecological responses from shallow lakes in the middle and lower reaches of the Yangtze River: Case studies on Longgan Lake and Taibai Lake

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The evolutions of diatom floras and the total phosphorous (TP) concentrations in the historical period were reconstructed for two lakes, Longgan and Taibai in the middle Yangtze River,based on high resolutional fossil diatom study from two sediment cores and an established regional diatom-TP transfer function. The TP concentration in Longgan Lake changed slightly in the range of 36-62 μg/L and kept its middle trophic level in the past 200 years. The changes of diatom assemblages reflect a macrophyte-dominated history of the lake. During the nineteenth century, the lake TP concentration increased comparatively, corresponding to the increase in abundance of benthic diatoms. The progressive increase of epiphytic diatoms since the onset of the twentieth century indicates the development of aquatic plants, coinciding with the twice drops of water TP level. The TP concentration in Taibai Lake kept a stable status about 50 μg/L before 1953 AD, while diatoms dominated by facultative planktonic Aulacoseira granulata shifted quickly to epiphytic diatom species, indicating a rapid expansion of aquatic vegetation. During 1953-1970 AD, the coverage of aquatic plants decreased greatly inferred by the low abundance of epiphytic diatoms as well as declined planktonic types, and the reconstructed TP concentration shows an obvious rising trend firstly, suggesting the beginning of the lake eutrophication. The lake was in the eutrophic condition after 1970, coinciding with the successive increase of planktonic diatoms. The comparison of the two lakes suggests the internal adjustment and purification function of aquatic plants for nutrients in water. The discrepancy of TP trends in the two lakes after 1960 reflects two different patterns of lake environmental response to human disturbance. Sediments in Taibai Lake clearly recorded the process of lake ecological transformation from the macrophyte-dominated stage to the algae-dominated stage. The limits of TP concentration (68-118

  2. Foraminíferos bentónicos de tres playas en Isla Barú (Caribe colombiano y su relación con algunos parámetros sedimentológicos

    Directory of Open Access Journals (Sweden)

    Parada Ruffinatti Carmen

    1995-11-01

    Full Text Available Benthic foraminiferal communities and sediments in three shores of Barú island are studied. These ones were selected because they have different characteristics. In Mohan beach, situed al norwest side of the island, the sediments are coarse grained, with high contents of calcium carbonate. In Marimberos beach, situated at Barbacoas bay, the sediments are something finer and of continental origino at Muertos beach, situated at southeastearn extreme, there are intermediate characteristics. About the biothic component, there are different distribution between the foraminiferal species, that are related with calcium carbonate, grain size and e/N relationship.Se estudian las comunidades de foraminíferos bentónicos y sedimentos en tres playas de isla Barú, escogidas por tener características diferentes. En playa Mohán, ubicada al costado noroeste de la isla, predomina el sedimento grueso con alto contenido de carbonato de calcio; en playa Marimberos, situada en la bahía de Barbacoas, se evidencia el aporte continental a través del canal del Dique y los sedimentos son algo más finos; en playa Muertos, ubicada al extremo sureste, las características son intermedias. En cuanto al componente biótico, se observan diferencias en la distribución de especies de foraminíferos, relacionadas con los cambios de porcentaje de carbonato de calcio, tamaño de grano y relación Carbono/Nitrógeno.

  3. Lake retention of manufactured nanoparticles

    NARCIS (Netherlands)

    Koelmans, A.A.; Quik, J.T.K.; Velzeboer, I.

    2015-01-01

    For twenty-five world lakes and three engineered nanoparticles (ENP), lake retention was calculated using a uniformly mixed lake mass balance model. This follows similar approaches traditionally used in water quality management. Lakes were selected such that lake residence times, depths and areal hy

  4. Lake retention of manufactured nanoparticles

    NARCIS (Netherlands)

    Koelmans, A.A.; Quik, J.T.K.; Velzeboer, I.

    2015-01-01

    For twenty-five world lakes and three engineered nanoparticles (ENP), lake retention was calculated using a uniformly mixed lake mass balance model. This follows similar approaches traditionally used in water quality management. Lakes were selected such that lake residence times, depths and areal hy

  5. Salting our freshwater lakes.

    Science.gov (United States)

    Dugan, Hilary A; Bartlett, Sarah L; Burke, Samantha M; Doubek, Jonathan P; Krivak-Tetley, Flora E; Skaff, Nicholas K; Summers, Jamie C; Farrell, Kaitlin J; McCullough, Ian M; Morales-Williams, Ana M; Roberts, Derek C; Ouyang, Zutao; Scordo, Facundo; Hanson, Paul C; Weathers, Kathleen C

    2017-04-25

    The highest densities of lakes on Earth are in north temperate ecosystems, where increasing urbanization and associated chloride runoff can salinize freshwaters and threaten lake water quality and the many ecosystem services lakes provide. However, the extent to which lake salinity may be changing at broad spatial scales remains unknown, leading us to first identify spatial patterns and then investigate the drivers of these patterns. Significant decadal trends in lake salinization were identified using a dataset of long-term chloride concentrations from 371 North American lakes. Landscape and climate metrics calculated for each site demonstrated that impervious land cover was a strong predictor of chloride trends in Northeast and Midwest North American lakes. As little as 1% impervious land cover surrounding a lake increased the likelihood of long-term salinization. Considering that 27% of large lakes in the United States have >1% impervious land cover around their perimeters, the potential for steady and long-term salinization of these aquatic systems is high. This study predicts that many lakes will exceed the aquatic life threshold criterion for chronic chloride exposure (230 mg L(-1)), stipulated by the US Environmental Protection Agency (EPA), in the next 50 y if current trends continue.

  6. Staging Mobilities

    DEFF Research Database (Denmark)

    Jensen, Ole B.

    that mobility is more than movement between point A and B. It explores how the movement of people, goods, information, and signs influences human understandings of self, other and the built environment. Moving towards a new understanding of the relationship between movement, interaction and environments......In recent years, the social sciences have taken a “mobilities turn.” There has been a developing realisation that mobilities do not “just happen.” Mobilities are carefully and meticulously designed, planned and staged (from above). However, they are equally importantly acted out, performed...... and lived as people are “staging themselves” (from below). Staging mobilities is a dynamic process between “being staged” (for example, being stopped at traffic lights) and the “mobile staging” of interacting individuals (negotiating a passage on the pavement). Staging Mobilities is about the fact...

  7. Advances in thermokarst lake research in permafrost regions

    Institute of Scientific and Technical Information of China (English)

    FuJun Niu; GuoDong Cheng; Jing Luo; ZhanJu Lin

    2014-01-01

    A-thermokarst-lake-is-defined-as-a-lake-occupying-a-closed-depression-formed-by-ground-settlement-following-thawing-of-ice-rich-permafrost-or-the-melting-of-massive-ice.-As-it-is-the-most-visible-morphologic-landscape-developed-during-the-process-of-permafrost-degradation,-we-reviewed-recent-literature-on-thermokarst-studies,-and-summarized-the-main-study-topics-as:-development-and-temporal-evolution,-carbon-release,-and-ecological-and-engineering-influence-of-thermokarst-lakes.-The-climate-warming,-forest-fires,-surface-water-pooling,-geotectonic-fault-and-anthropogenic-ac-tivity-are-the-main-influencing-factors-that-cause-an-increase-of-ground-temperatures-and-melting-of-ice-rich-permafrost,-resulting-in-thermokarst-lake-formation.-Normally-a-thermokarst-lake-develops-in-3-5-stages-from-initiation-to-perma-frost-recovery.-Geo-rectified-aerial-photographs-and-remote-sensing-images-show-that-thermokarst-lakes-have-been-mainly-experiencing-the-process-of-shrinkage-or-disappearance-in-most-regions-of-the-Arctic,-while-both-lake-numbers-and-areas-on-the-Qinghai-Tibet-Plateau-have-increased.-Field-studies-and-modeling-indicates-that-carbon-release-from-thermokarst-lakes-can-feedback-significantly-to-global-warming,-thus-enhancing-our-understanding-of-the-influences-of-thermokarst-lakes-on-the-ecological-environment,-and-on-regional-groundwater-through-drainage.-Based-on-field-mon-itoring-and-numerical-simulations,-infrastructure-stability-can-be-affected-by-thermal-erosion-of-nearby-thermokarst-lakes.-This-review-was-undertaken-to-enhance-our-understanding-of-thermokarst-lakes,-and-providing-references-for-future-comprehensive-studies-on-thermokarst-lakes.

  8. Clasificación e impacto ambiental de los residuos sólidos generados en las playas de Riohacha, La Guajira, Colombia

    Directory of Open Access Journals (Sweden)

    Elin Márquez Gulloso

    2011-01-01

    Full Text Available En la presente investigación se realizó una clasificación y valoración de impacto de los residuos sólidos generados en las playas de Riohacha, desde Valle de los Cangrejos hasta el Barrio Marbella. Se seleccionaron cinco estaciones de muestreo; en cada una se ubicaron transectos perpendiculares a la línea de costa; sobre estos se trazaron cuadrantes paralelos para la recolección de residuos sólidos. Además, se aplicaron encuestas a los usuarios y vendedores de las playas para determinar la percepción de olores ofensivos y se cuantificó la carga turística. Los datos de residuos se analizaron con el software estadístico SPSS 12,0 a través de la prueba Kruskal-wallis con el 97,5% de significancia y se valoró el impacto con el Método de Leopold (1971. En el inventario realizado los materiales que registraron mayor presencia fueron materia orgánica, plásticos, misceláneos y vidrios, siendo los residuos sólidos orgánicos los que obtuvieron mayor porcentaje. Las mayores concentraciones de usuarios se presentaron en la Zona Activa (ZA y Zona Pasiva (ZP, coincidiendo con la cantidad de residuos recolectados en cada estación de muestreo. Los olores ofensivos de mayor incidencia fueron basura, orina, excrementos humano y animal. La cantidad y el tipo de material están condicionados por las características del área y la influencia de actividades socioeconómicas. Las cantidades de residuos sólidos en las estaciones durante el 1º y 2º muestreo no presentaron diferencias significativas, siendo las principales causas de generación la disposición de desechos por residentes y visitantes, la pesca y la deposición de excrementos en la playa.

  9. 2016 Lake Michigan Lake Trout Working Group Report

    Science.gov (United States)

    Madenjian, Charles P.; Breidert, Brian; Boyarski, David; Bronte, Charles R.; Dickinson, Ben; Donner, Kevin; Ebener, Mark P.; Gordon, Roger; Hanson, Dale; Holey, Mark; Janssen, John; Jonas, Jory; Kornis, Matthew; Olsen, Erik; Robillard, Steve; Treska, Ted; Weldon, Barry; Wright, Greg D.

    2017-01-01

    This report provides a review on the progression of lake trout rehabilitation towards meeting the Salmonine Fish Community Objectives (FCOs) for Lake Michigan (Eshenroder et. al. 1995) and the interim goal and evaluation objectives articulated in A Fisheries Management Implementation Strategy for the Rehabilitation of Lake Trout in Lake Michigan (Dexter et al. 2011); we also include data describing lake trout stocking and mortality to portray the present state of progress towards lake trout rehabilitation.

  10. Casa en Playa Bonita

    OpenAIRE

    2004-01-01

    La realidad del clima árido costero puede leerse como limitante y como libertad, simultáneamente. La falta de lluvias y la baja oscilación térmica, producida por la presencia del mar, ofrecen la posibilidad de una arquitectura elemental que se resuelve, con cierta brutalidad, en términos mínimos. Sin articulaciones, esta casa de fin de semana dispone patios, salas y terrazas relacionadas al cielo y a los horizontes extensos del desierto y el océano.

  11. Determining Long-Term Trends of Four Fast-Eutrophicated Lakes in China and Finland

    DEFF Research Database (Denmark)

    Liao, Mengna; Yu, Ge; Ventelä, Anne-Mari

    2016-01-01

    in different trophic stages, which represent three developing stages from forest- to agriculture-, and then to urban-lake, typically in Lakes Lugu, Taibai, and Taihu. To determine long-term water quality trends, the three lakes were chosen for statistic analysis on dominant effects on the diatom...... by increases in tourism, farming and urbanization respectively. Water quality changes in Lakes Lugu, Taibai and Taihu captured 68.4%, 54.9%, and 86.0% of the temperature variations before the turning points. The anthropogenic impacts explained 84.0%, 96.4% and 96.0% of the water quality variations after...

  12. Properties of solonetzes on terraces of salt lakes Bulukhta and Khaki in the Caspian Lowland

    Science.gov (United States)

    Shabanova, N. P.; Lebedeva, M. P.

    2016-06-01

    A comparative assessment of pedogenetic processes in solonetzes (Calcic Gypsic Salic Solonetzes (Siltic, Albic, Cutanic, Differentic)) developing on terraces of lake depressions within the Volga-Ural interfluve of the Caspian Lowland has been performed on the basis of data on their macro- and micromorphological features and chemical, physicochemical, and physical properties. The studied soils have number of common characteristics shaped by the humus-accumulative, solonetzic, eluvial-illuvial, calcification, and gypsification processes. However, it is shown that macro- and micromorphological indicators of solonetzic processes (the development of clay-humus coatings and the character of structural units in the solonetzic (B) horizon) do not always agree with the modern physicochemical conditions of the development of this process. This is explained by differences in the degree and chemistry of the soil salinization and the depth and salinity of the groundwater. Solonetzes developing on the second terrace of Playa Khaki are distinguished by the highest water content and maximum thickness of the horizons depleted of soluble salts. They are characterized by the well-pronounced humus-accumulative process leading to the development of the light-humus (AJ) horizon. In other solonetzes, the accumulation of humus is weaker, and their topsoil part can be diagnosed as the solonetzic-eluvial (SEL) horizon. Active solodic process and illuviation of organomineral substances with the development of thick coatings and infillings in the B horizon are also typical of solonetzes on the second terrace of Playa Khaki. Micromorphological data indicate that, at present, layered clayey coatings in these soils are subjected to destruction and in situ humification owing to the active penetration of plant roots into the coatings with their further biogenic processing by the soil microfauna. The process of gleyzation (as judged from the number of Fe-Mn concentrations) is most active in

  13. Hydrography - Lakes Assessments - Non Attaining

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — This layer shows only non attaining lakes of the Integrated List. The Lakes Integrated List represents lake assessments in an integrated format for the Clean Water...

  14. Boat Dwellers of Weishan Lake

    Institute of Scientific and Technical Information of China (English)

    JENNIFER; LIM

    1998-01-01

    IN the south of Shandong Province, Weishan Lake is the largest freshwater lake in northern China. Under the bright blue sky, it gleams like a large mirror. "As the sun is about to set, Weishan Lake is quiet…" Humming

  15. Formation and water environmental evolution of the Nansihu Lake

    Institute of Scientific and Technical Information of China (English)

    ZHANGZulu; SHENJi; LIUEnfeng; SUNQingyi; JIANGLuguang

    2003-01-01

    Through high-resolution research of sedimental chronology and the sediment environmental indexes,such as graininess ,minerals,magnetic parameters,pigment content organic carbon and chronology in Ds-core and Ws-core in Nansihu Lake,the authors analyze the formation cause of the Nansihu Lake and its water environmental changes,Historical documents are also analyzed here in order to reach the conclusion .Researches indicate that the Nansihu Lake came into being about 2500 aBP and its evolution succession can be divided into four stages.In this evolution process ,several scattered lakes merge into one large lake in the east of China,This process is distinctively affected by the overflow of the Yellow River,the excavation of the Grand Canal and other human activities.

  16. CARACTERIZACIÓN FISICOQUÍMICA DE CUARZO EN EL MUNICIPIO DE LA PLAYA DE BELÉN DEPARTAMENTO NORTE DE SANTANDER

    Directory of Open Access Journals (Sweden)

    Lina Marcela Hoyos Palacio

    2015-07-01

    Full Text Available Quartz is a silicate, is available in a variety of geological conditions, appears in many igneous and metamorphic rocks, and is a major constituent of granite pegmatite. Among the minerals, quartz is the closest to a pure chemical compound and has constant physical properties due to their applications and uses becomes a material that contributes to improving the living conditions of man; for that reason becomes obvious know their properties to propose optimal applications. To this end the physicochemical characterization of quartz in the town of Playa of Belen Norte de Santander (Colombia Department, using elementary techniques through studies to establish the physical and chemical properties of this mineral is described. A technique of scanning electron microscopy (SEM was used to disperse energy analyzer (EDS, X-ray diffraction (XRD, thermogravimetric (TGA and differential thermogravimetric analysis (DTG. The compositional, chemical and morphological characteristics are obtained and the thermal behavior of the composition according to is evaluated.

  17. Estimación de costos de obras de recuperación de playas en la costa de Yucatán

    OpenAIRE

    R. Ancona-Ayora; J. Pech-Pérez; C. Zetina-Moguel

    2010-01-01

    El incremento de actividades humanas y los eventos climáticos extremos han acelerado la erosión costera en Yucatán alentando la construcción de obras de protección costera. En este artículo se describe una herramienta computacional para estimar costos aproximados de construcción usando el método paramétrico de estimación de costos. Los cálculos se basan en información física preliminar y las proyecciones de uso de la playa. El desarrollo de la herramienta computacional requirió de una revisió...

  18. Composición químico-nutricional en diferentes tallas y sexos del cambute, Strombus gracilior (Mesogastropoda: Strombidae) de Playa Panamá, Costa Rica

    OpenAIRE

    Jiménez-Arce, G.

    2016-01-01

    Se obtuvieron 74 ejemplares de cambute (Strombus gracilior) de Playa Panamá (lOO 35' 45" N, 840 40' 09" W), Costa Rica. La proporción de sexos fue de 1:1 y el ámbito de talla 70- 80mm (longitud total). El rendimiento promedio fue de 80% de carne comestible. Los valores promedio de los macronutrientes para ambas tallas fueron: humedad 72.6% machos y 70.9% hembras. proteínas 19.09g% machos y 26.89g% hembras; carbohidratos 1.85g% machos y 1.35g% hembras; fibra cruda O.44g% machos y hembras. Las ...

  19. Clasificación morfológica de las playas y modelado del perfil transversal en Valencia, Alicante y Murcia

    OpenAIRE

    López Úbeda, Isabel

    2016-01-01

    Uno de los problemas más importantes en el mundo es la erosión costera. Alrededor del 70% de las playas de arena están sufriendo erosión. Las costas representan en la mayoría de los casos las zonas turísticas y por lo tanto la prevención de la erosión es una necesidad común. Generalmente, para hacer frente a este problema se realizan regeneraciones y/o obras de defensa costera, lo que conduce a costos económicos. En el caso concreto de España, el turismo es una importante fuente de ingresos, ...

  20. Anidación y manejo de la tortuga golfina (Lepidochelys olivacea en la playa La Cuevita, Bahía Solano, Chocó, Colombia

    Directory of Open Access Journals (Sweden)

    Hinestroza, Lina María

    2001-02-01

    Full Text Available Durante la estación de anidación de 1999, documentamos algunos aspectos del comportamiento de anidación de la colonia de Lepidochelys olivacea que desova en la playa La Cuevita en el Pacífico colombiano. Adicionalmente, evaluamos los resultados del programa de maneje por transferencia y protección de nidos para esta estación reproductiva y lo comparamos con años anteriores. Todos los nidos depositados en esta playa que no logran ser transferidos al corral de protección. son depredados por humanos, al igual que una buena proporción de las hembras anidantes. Trasladamos 365 nidos (30197 huevos, de los 377 desoves registrados. El promedio del LCC de las hembras fue de 66 cm (SD= 2,47 y el promedio del número de huevos por nido fue de 102 (SD= 23,04. A diferencia de la estación de 1998, en la presente estación se presentó un pico de anidación evidente y la preferencia de anidación fue en la Lona media de la playa, seguida por la zona de lavado. El éxito de eclosión estimado con base en 304 de los 365 nidos transferidos fue de 71.4% y el éxito reproductivo de 71.8%. Las causas principales de mortalidad dentro del tortugario fueron: escaso o noto desarrollo embrionario. infestación de larvas de moscas en toda o parte de la nidada. asfixia de los neonatos por compactación de la arena. y picaduras por parte de hormigas. El intervalo de temperaturas de incubación estuvo entre los 28,9°C y los 29,4°C, con un promedio de 29.1°C, presentando 51 días de incubación. La evaluación de las proporciones sexuales neonatales de los nidos transferidos fue de 6: 1 en favor de los machos. Nuestros resultados indican que playa La Cuevita es un importante sitio de anidación de Lepidochelys olivacea en Sudamérica. Sin embargo, se deben seguir evaluando las estrategias de manejo empleadas para permitir la eclosión in situ de nidadas, mediante el control de las tasas de depredación humana, e intentar adelantar estudios para determinar

  1. Geology and hydrology between Lake McMillan and Carlsbad Springs, Eddy County, New Mexico

    Science.gov (United States)

    Cox, Edward Riley

    1967-01-01

    The hydrology of the Pecos River valley between Lake McMillan and Carlsbad Springs, Eddy County, N. Mex., is influenced by facies changes in rocks of Permian age. Water stored for irrigation leaks from Lake McMillan into evaporite rocks, principally gypsum, of the Seven Rivers Formation and from Lake Avalon into carbonate rocks of the Tansill Formation. This leakage returns to the Pecos River at Major Johnson Springs and Carlsbad Springs. The river has perennial flow between Major Johnson Springs and Lake Avalon, but it loses water into evaporite rocks of the Yates Formation in this reach. Ground-water movement is generally toward the Pecos River in aquifers in the Pecos River valley except in the Rustler Formation east of the river where it moves southeastward toward playas east of Lake Avalon. The chloride content of ground and surface waters indicates that surface water moves from some reaches of the Pecos River and from surface-storage reservoirs to aquifers and also indicates the degree of mixing of ground and surface waters. About 45,000 acre-feet of ground water is stored in highly permeable rocks in a 3-mile wide part of the Seven Rivers Formation between Lake McMillan and Major Johnson Springs. This water in storage comes from leakage from Lake McMillan and from alluvium north of the springs. The flow of Major Johnson Springs is derived from this aquifer. That part of the flow derived from the alluvium north of the springs averaged 13 cfs (cubic feet per second) from 1953 through 1959 ; about 8 cfs of this flow had not been previously measured at gaging stations on the Pecos River and its tributaries. The most favorable plans for increasing terminal storage of the Carlsbad Irrigation District are to construct a dam at the Brantley site (at the downstream end of Major Johnson Springs), or to use underground storage in the permeable Seven Rivers Formation between Lake McMillan and Major Johnson brings in conjunction with surface storage. To avoid excessive

  2. Staging atmospheres

    DEFF Research Database (Denmark)

    Bille, Mikkel; Bjerregaard, Peter; Sørensen, Tim Flohr

    2015-01-01

    The article introduces the special issue on staging atmospheres by surveying the philosophical, political and anthropological literature on atmosphere, and explores the relationship between atmosphere, material culture, subjectivity and affect. Atmosphere seems to occupy one of the classic...... localities of tensions between matter and the immaterial, the practical and the ideal, and subject and object. In the colloquial language there can, moreover, often seem to be something authentic or genuine about atmosphere, juxtaposing it to staging, which is implied to be something simulated or artificial....... This introduction seeks to outline how a number of scholars have addressed the relationship between staged atmospheres and experience, and thus highlight both the philosophical, social and political aspects of atmospheres...

  3. Lake sediment records on climate change and human activities in the Xingyun Lake catchment, SW China.

    Science.gov (United States)

    Zhang, Wenxiang; Ming, Qingzhong; Shi, Zhengtao; Chen, Guangjie; Niu, Jie; Lei, Guoliang; Chang, Fengqin; Zhang, Hucai

    2014-01-01

    Sediments from Xinyun Lake in central Yunnan, southwest China, provide a record of environmental history since the Holocene. With the application of multi-proxy indicators (total organic carbon (TOC), total nitrogen (TN), δ13C and δ15N isotopes, C/N ratio, grain size, magnetic susceptibility (MS) and CaCO3 content), as well as accelerator mass spectrometry (AMS) 14C datings, four major climatic stages during the Holocene have been identified in Xingyun's catchment. A marked increase in lacustrine palaeoproductivity occurred from 11.06 to 9.98 cal. ka BP, which likely resulted from an enhanced Asian southwest monsoon and warm-humid climate. Between 9.98 and 5.93 cal. ka BP, a gradually increased lake level might have reached the optimum water depth, causing a marked decline in coverage by aquatic plants and lake productivity of the lake. This was caused by strong Asian southwest monsoon, and coincided with the global Holocene Optimum. During the period of 5.60-1.35 cal. ka BP, it resulted in a warm and dry climate at this stage, which is comparable to the aridification of India during the mid- and late Holocene. The intensifying human activity and land-use in the lake catchment since the early Tang Dynasty (∼1.35 cal. ka BP) were associated with the ancient Dian culture within Xingyun's catchment. The extensive deforestation and development of agriculture in the lake catchment caused heavy soil loss. Our study clearly shows that long-term human activities and land-use change have strongly impacted the evolution of the lake environment and therefore modulated the sediment records of the regional climate in central Yunnan for more than one thousand years.

  4. Lake sediment records on climate change and human activities in the Xingyun Lake catchment, SW China.

    Directory of Open Access Journals (Sweden)

    Wenxiang Zhang

    Full Text Available Sediments from Xinyun Lake in central Yunnan, southwest China, provide a record of environmental history since the Holocene. With the application of multi-proxy indicators (total organic carbon (TOC, total nitrogen (TN, δ13C and δ15N isotopes, C/N ratio, grain size, magnetic susceptibility (MS and CaCO3 content, as well as accelerator mass spectrometry (AMS 14C datings, four major climatic stages during the Holocene have been identified in Xingyun's catchment. A marked increase in lacustrine palaeoproductivity occurred from 11.06 to 9.98 cal. ka BP, which likely resulted from an enhanced Asian southwest monsoon and warm-humid climate. Between 9.98 and 5.93 cal. ka BP, a gradually increased lake level might have reached the optimum water depth, causing a marked decline in coverage by aquatic plants and lake productivity of the lake. This was caused by strong Asian southwest monsoon, and coincided with the global Holocene Optimum. During the period of 5.60-1.35 cal. ka BP, it resulted in a warm and dry climate at this stage, which is comparable to the aridification of India during the mid- and late Holocene. The intensifying human activity and land-use in the lake catchment since the early Tang Dynasty (∼1.35 cal. ka BP were associated with the ancient Dian culture within Xingyun's catchment. The extensive deforestation and development of agriculture in the lake catchment caused heavy soil loss. Our study clearly shows that long-term human activities and land-use change have strongly impacted the evolution of the lake environment and therefore modulated the sediment records of the regional climate in central Yunnan for more than one thousand years.

  5. Chironomid (Diptera species recorded from UK lakes as pupal exuviae

    Directory of Open Access Journals (Sweden)

    L.P. Ruse

    2013-09-01

    Full Text Available An inventory of chironomid species (Diptera, Chironomidae data collected from 221 lake basins or reservoirs is detailed together with major physical and chemical characteristics of these waterbodies. Aquatic species of Chironomidae must rise to the water surface for adult emergence. Floating exuviae are transported by wind and water currents to lakeshores. Species data were obtained by collecting lake marginal floating pupal exuviae representing juvenile stages dwelling from across the lake. Among the 450 species found, several were new records for the British Isles.

  6. Analysis of remote sensing data for geothermal exploration over Fish Lake Valley, Esmeralda County, Nevada

    Science.gov (United States)

    Littlefield, Elizabeth F.

    The purpose of this study was to identify and map hydrothermal alteration and geothermal deposits in northern Fish Lake Valley, Nevada using both visible, near, shortwave infrared (0.4-2.5 microm) and thermal infrared (8-12 microm) remote sensing data. Visible, near, and shortwave infrared data were collected by four airborne instruments including NASA's Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) and MODIS-ASTER (MASTER) instruments, HyVista Corporation's HyMap sensor, and SpecTIR Corporation's ProSpecTIR instrument. MASTER also collected thermal infrared data over Fish Lake Valley. Hydrothermal alteration minerals and hot spring deposits were identified using diagnostic spectra extracted from the remote sensing data. Mapping results were verified in the field using a portable spectrometer. Two areas of opaline sinter and travertine deposits were identified west of the Fish Lake Valley playa. Field observation reveals the alternating nature of these beds, which likely reflects fluctuating hot spring fluid chemistries. Sinter and travertine were likely deposited around fault-related hot springs during the Pleistocene when the water table was higher. Previously undiscovered Miocene crystalline travertine was identified within the Emigrant Hills near Columbus Salt Marsh. Argillic alteration was mapped in parts of the ranges surrounding Fish Lake Valley. Kaolinite, and to a lesser extent, muscovite and montmorillonite, were used as indicator minerals for argillic alteration. In these regions, thermal fluids were likely discharged from faults to alter rhyolite tuff. Mineral maps were synthesized with previously published geologic data and used to delineate four new targets for future geothermal exploration. The abundant hot spring deposits along the edge of the Volcanic Hills combined with argillic alteration minerals mapped in the ranges suggest geothermal influence throughout much of the valley.

  7. Great Lakes Teacher's Guide.

    Science.gov (United States)

    Reid, Ron

    The Great Lakes are one of the world's greatest reservoirs of fresh water, the foundation of Ontario's economic development, a primary force in ecological systems, and a base for pleasure and recreation. They are also a magnificent resource for the teachers of Ontario. Study of the Great Lakes can bring to life the factors that shape the ecology…

  8. Marine lakes of Indonesia

    NARCIS (Netherlands)

    Becking, Leontine Elisabeth

    2012-01-01

    The objective of this thesis was to obtain insight into the processes that play a role in biodiversity patterns of tropical marine species by using marine lakes as a model. Marine lakes are landlocked water bodies that maintain a marine character through narrow submarine connections to the sea. Two

  9. The Great Lakes.

    Science.gov (United States)

    Seasons, 1987

    1987-01-01

    The Great Lakes are one of the world's greatest reserviors of fresh water, the foundation of Ontario's economic development, a primary force in ecological systems, and a base for pleasure and recreation. These lakes and their relationship with people of Canada and the United States can be useful as a subject for teaching the impact of human…

  10. Marine lakes of Indonesia

    NARCIS (Netherlands)

    Becking, Leontine Elisabeth

    2012-01-01

    The objective of this thesis was to obtain insight into the processes that play a role in biodiversity patterns of tropical marine species by using marine lakes as a model. Marine lakes are landlocked water bodies that maintain a marine character through narrow submarine connections to the sea. Two

  11. Glacial lakes in the Horgos river basin and their outbreak risk assessment

    Directory of Open Access Journals (Sweden)

    A. P. Medeu

    2013-01-01

    Full Text Available The river Khorgos (in Kazakhstan – Korgas is a boundary river between Kazakhstan and China. Its basin is located in the central part of southern slope of Dzhungarskiy (Zhetysu Alatau range. According to agreement between Kazakhstan and China at the boundary transition of Khorgos in the floodplain of the river Khorgos the large Center of Frontier Cooperation is erected. Estimation of safety of the mentioned object including connection with possible glacial lakes outbursts has the importance of political-economical value. Nowadays development of glacial lakes in the overhead part of Khorgos river basin has reached apogee. As a roof we can mention the maximum of total glacial lakes area (1,7 million m² in 41 lakes and emptied kettles of former glacial lakes. Six lakes reached highly dangerous outburst stage: the volume of lakes reached some million m³, maximum depth up to 30–40 m. Focal ground filtration of the water from lakes takes place. Development of glacial lakes in Khorgos river basin will continue, and these lakes give and will give real danger for the Center of Frontier Cooperation in case of outburst of naturally dammed lake Kazankol with the similar mechanism of Issyk lake outburst, occurred in 1963 in ZailijskiyAlatau (Ile Alatau.

  12. Lake trout in northern Lake Huron spawn on submerged drumlins

    Science.gov (United States)

    Riley, Stephen C.; Binder, Thomas; Wattrus, Nigel J.; Faust, Matthew D.; Janssen, John; Menzies, John; Marsden, J. Ellen; Ebener, Mark P.; Bronte, Charles R.; He, Ji X.; Tucker, Taaja R.; Hansen, Michael J.; Thompson, Henry T.; Muir, Andrew M.; Krueger, Charles C.

    2014-01-01

    Recent observations of spawning lake trout Salvelinus namaycush near Drummond Island in northern Lake Huron indicate that lake trout use drumlins, landforms created in subglacial environments by the action of ice sheets, as a primary spawning habitat. From these observations, we generated a hypothesis that may in part explain locations chosen by lake trout for spawning. Most salmonines spawn in streams where they rely on streamflows to sort and clean sediments to create good spawning habitat. Flows sufficient to sort larger sediment sizes are generally lacking in lakes, but some glacial bedforms contain large pockets of sorted sediments that can provide the interstitial spaces necessary for lake trout egg incubation, particularly if these bedforms are situated such that lake currents can penetrate these sediments. We hypothesize that sediment inclusions from glacial scavenging and sediment sorting that occurred during the creation of bedforms such as drumlins, end moraines, and eskers create suitable conditions for lake trout egg incubation, particularly where these bedforms interact with lake currents to remove fine sediments. Further, these bedforms may provide high-quality lake trout spawning habitat at many locations in the Great Lakes and may be especially important along the southern edge of the range of the species. A better understanding of the role of glacially-derived bedforms in the creation of lake trout spawning habitat may help develop powerful predictors of lake trout spawning locations, provide insight into the evolution of unique spawning behaviors by lake trout, and aid in lake trout restoration in the Great Lakes.

  13. Lake metabolism scales with lake morphometry and catchment conditions

    DEFF Research Database (Denmark)

    Stæhr, Peter A.; Baastrup-Spohr, Lars; Jensen, Kaj Sand;

    2012-01-01

    We used a comparative data set for 25 lakes in Denmark sampled during summer to explore the influence of lake morphometry, catchment conditions, light availability and nutrient input on lake metabolism. We found that (1) gross primary production (GPP) and community respiration (R) decline with lake...... area, water depth and drainage ratio, and increase with algal biomass (Chl), dissolved organic carbon (DOC) and total phosphorus (TP); (2) all lakes, especially small with less incident light, and forest lakes with high DOC, have negative net ecosystem production (NEP ... decreases with lake area and water depth as a consequence of lower input of nutrients and organic matter per unit water volume; (4) the influence of benthic processes on free water metabolic measures declines with increasing lake size; and (5) with increasing lake size, lake metabolism decreases...

  14. Staging Mobilities

    DEFF Research Database (Denmark)

    Jensen, Ole B.

    In recent years, the social sciences have taken a “mobilities turn.” There has been a developing realisation that mobilities do not “just happen.” Mobilities are carefully and meticulously designed, planned and staged (from above). However, they are equally importantly acted out, performed...... that mobility is more than movement between point A and B. It explores how the movement of people, goods, information, and signs influences human understandings of self, other and the built environment. Moving towards a new understanding of the relationship between movement, interaction and environments......, the book asks: what are the physical, social, technical, and cultural conditions to the staging of contemporary urban mobilities?...

  15. The geomorphology of Patagonian ice dammed lake basins: Insights from remote sensing of a modern lake and reconstruction of a Late Quaternary lake drainage event

    Science.gov (United States)

    Thorndycraft, Varyl

    2016-04-01

    The geomorphology of ice dammed lake basins can be complex due to geomorphic responses to multiple base level changes from repeated filling and emptying, as well as the potential for catastrophic drainage events. Refining landscape models of Quaternary ice dammed palaeolake systems has the potential to improve our understanding of glacier and meltwater dynamics during deglaciation phases. In this poster two case studies are presented to shed light on the range of geomorphic processes exhibited within ice dammed lake basins. Using Google Earth Pro and repeat LANDSAT imagery the geomorphology resulting from multiple base level changes of an ice dammed lake of the Viedma Glacier (Southern Patagonia Icefield) is presented. The LANDSAT imagery shows transgressive lake phases inundating already formed delta and terrace surfaces, whilst the high resolution Google Earth Pro images reveal a complex suite of incised terrace levels developed on the valley floor following lake drainage events. Secondly, the impact of catastrophic drainage of the Late Pleistocene Palaeolake Cochrane (Northern Patagonia Icefield) is investigated through geomorphological mapping. Here an outburst flood and rapid lowering of the lake has led to large scale eddy scouring of glacio-lacustrine sediments, with scarp slopes of ca. 30-40 m in height, and the formation of boulder bars during the final stages of lake fall. The implications of the mapping for interpretations of Late Quaternary palaeolake sediment-landform assemblages and rates of landscape change are discussed.

  16. Precipitation and lake-level changes in the West and Midwest over the past 10,000 to 24,000 years. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Webb, T. III; Street, F.A.; Howe, S.

    1980-02-04

    The goal of the research described in this report is to document the climatic variability over the past 10,000 to 20,000 years in areas in which sites may be designated for the burial of nuclear wastes. Three separate data sets were studied, and the results are presented in three chapters. The first data set consisted of radiocarbon dates documenting past changes in lake levels in lakes and playas in the western United States. The sites were mapped where water levels were higher than the levels today and were presented in a table telling what evidence is available at each site. The lake-level fluctuations for the past 24,000 years at sites in the West were also mapped and time series for these fluctuations at four sites were presented. The second data set was a selection of the published radiocarbon-dated pollen diagrams from the western United States. These data are a valuable source of climatic information and complement the geological evidence of lake-level fluctuations in the West. A table is presented that gives the location, elevation, and number of radiocarbon dates for each site. The third data set was a set of fossil pollen data from 20 sites in the upper Midwest. These data were calibrated in terms of precipitation changes over the past 10,000 years, and maps are presented of the estimated precipitation changes between 10,000 and 7000 years ago and between 7000 years ago and today.

  17. Hydrology and water quality of East Lake Tohopekaliga, Osceola County, Florida

    Science.gov (United States)

    Schiffer, Donna M.

    1987-01-01

    East Lake Tohopekaliga, one of the major lakes in central Florida, is located in the upper Kissimmee River basin in north-east Osceola County. It is one of numerous lakes in the upper basin used for flood control, in addition to recreation and some irrigation of surrounding pasture. This report is the fourth in a series of lake reconnaissance studies in the Kissimmee River basin prepared in cooperation with the South Florida Water Management District. The purpose of the report is to provide government agencies and the public with a brief summary of the lake 's hydrology and water quality. Site information is given and includes map number, site name, location, and type of data available (specific conductivity, pH, alkalinity, turbidity, color, dissolved oxygen, hardness, dissolved chlorides, dissolved sodium, dissolved calcium, dissolved magnesium, dissolved potassium, nitrogen, ammonia, nitrates, carbon and phosphorus). The U.S. Geological Survey (USGS) maintained a lake stage gaging station on East Lake Tohopekaliga from 1942 to 1968. The South Florida Water Management District has recorded lake stage since 1963. Periodic water quality samples have been collected from the lake by the South Florida Water Management District and USGS. Water quality and discharge data have been collected for one major tributary to the lake, Boggy Creek. Although few groundwater data are available for the study area, results of previous studies of the groundwater resources of Osceola County are included in this report. To supplement the water quality data for East Lake Tohopekaliga, water samples were collected at selected sites in November 1982 (dry season) and in August 1983 (rainy season). Samples were taken at inflow points, and in the lake, and vertical profiles of dissolved oxygen and temperature were measured in the lake. A water budget from an EPA report on the lake is also included. (Lantz-PTT)

  18. Ecology under lake ice.

    Science.gov (United States)

    Hampton, Stephanie E; Galloway, Aaron W E; Powers, Stephen M; Ozersky, Ted; Woo, Kara H; Batt, Ryan D; Labou, Stephanie G; O'Reilly, Catherine M; Sharma, Sapna; Lottig, Noah R; Stanley, Emily H; North, Rebecca L; Stockwell, Jason D; Adrian, Rita; Weyhenmeyer, Gesa A; Arvola, Lauri; Baulch, Helen M; Bertani, Isabella; Bowman, Larry L; Carey, Cayelan C; Catalan, Jordi; Colom-Montero, William; Domine, Leah M; Felip, Marisol; Granados, Ignacio; Gries, Corinna; Grossart, Hans-Peter; Haberman, Juta; Haldna, Marina; Hayden, Brian; Higgins, Scott N; Jolley, Jeff C; Kahilainen, Kimmo K; Kaup, Enn; Kehoe, Michael J; MacIntyre, Sally; Mackay, Anson W; Mariash, Heather L; McKay, Robert M; Nixdorf, Brigitte; Nõges, Peeter; Nõges, Tiina; Palmer, Michelle; Pierson, Don C; Post, David M; Pruett, Matthew J; Rautio, Milla; Read, Jordan S; Roberts, Sarah L; Rücker, Jacqueline; Sadro, Steven; Silow, Eugene A; Smith, Derek E; Sterner, Robert W; Swann, George E A; Timofeyev, Maxim A; Toro, Manuel; Twiss, Michael R; Vogt, Richard J; Watson, Susan B; Whiteford, Erika J; Xenopoulos, Marguerite A

    2017-01-01

    Winter conditions are rapidly changing in temperate ecosystems, particularly for those that experience periods of snow and ice cover. Relatively little is known of winter ecology in these systems, due to a historical research focus on summer 'growing seasons'. We executed the first global quantitative synthesis on under-ice lake ecology, including 36 abiotic and biotic variables from 42 research groups and 101 lakes, examining seasonal differences and connections as well as how seasonal differences vary with geophysical factors. Plankton were more abundant under ice than expected; mean winter values were 43.2% of summer values for chlorophyll a, 15.8% of summer phytoplankton biovolume and 25.3% of summer zooplankton density. Dissolved nitrogen concentrations were typically higher during winter, and these differences were exaggerated in smaller lakes. Lake size also influenced winter-summer patterns for dissolved organic carbon (DOC), with higher winter DOC in smaller lakes. At coarse levels of taxonomic aggregation, phytoplankton and zooplankton community composition showed few systematic differences between seasons, although literature suggests that seasonal differences are frequently lake-specific, species-specific, or occur at the level of functional group. Within the subset of lakes that had longer time series, winter influenced the subsequent summer for some nutrient variables and zooplankton biomass. © 2016 The Authors. Ecology Letters published by CNRS and John Wiley & Sons Ltd.

  19. Yellowstone Lake Nanoarchaeota

    Directory of Open Access Journals (Sweden)

    Scott eClingenpeel

    2013-09-01

    Full Text Available Considerable Nanoarchaeota novelty and diversity were encountered in Yellowstone Lake, Yellowstone National Park, where sampling targeted lake floor hydrothermal vent fluids, streamers and sediments associated with these vents, and in planktonic photic zones in three different regions of the lake. Significant homonucleotide repeats (HR were observed in pyrosequence reads and in near full-length Sanger sequences, averaging 112 HR per 1,349 bp clone and could confound diversity estimates derived from pyrosequencing, resulting in false nucleotide insertions or deletions (indels. However, Sanger sequencing of two different sets of PCR clones (110 bp, 1349 bp demonstrated that at least some of these indels are real. The majority of the Nanoarchaeota PCR amplicons were vent associated; however, curiously, one relatively small Nanoarchaeota OTU (70 pyrosequencing reads was only found in photic zone water samples obtained from a region of the lake furthest removed from the hydrothermal regions of the lake. Extensive pyrosequencing failed to demonstrate the presence of an Ignicoccus lineage in this lake, suggesting the Nanoarchaeota in this environment are associated with novel Archaea hosts. Defined phylogroups based on near full-length PCR clones document the significant Nanoarchaeota 16S rRNA gene diversity in this lake and firmly establish a terrestrial clade distinct from the marine Nanoarcheota as well as from other geographical locations.

  20. Yellowstone lake nanoarchaeota.

    Science.gov (United States)

    Clingenpeel, Scott; Kan, Jinjun; Macur, Richard E; Woyke, Tanja; Lovalvo, Dave; Varley, John; Inskeep, William P; Nealson, Kenneth; McDermott, Timothy R

    2013-01-01

    Considerable Nanoarchaeota novelty and diversity were encountered in Yellowstone Lake, Yellowstone National Park (YNP), where sampling targeted lake floor hydrothermal vent fluids, streamers and sediments associated with these vents, and in planktonic photic zones in three different regions of the lake. Significant homonucleotide repeats (HR) were observed in pyrosequence reads and in near full-length Sanger sequences, averaging 112 HR per 1349 bp clone and could confound diversity estimates derived from pyrosequencing, resulting in false nucleotide insertions or deletions (indels). However, Sanger sequencing of two different sets of PCR clones (110 bp, 1349 bp) demonstrated that at least some of these indels are real. The majority of the Nanoarchaeota PCR amplicons were vent associated; however, curiously, one relatively small Nanoarchaeota OTU (71 pyrosequencing reads) was only found in photic zone water samples obtained from a region of the lake furthest removed from the hydrothermal regions of the lake. Extensive pyrosequencing failed to demonstrate the presence of an Ignicoccus lineage in this lake, suggesting the Nanoarchaeota in this environment are associated with novel Archaea hosts. Defined phylogroups based on near full-length PCR clones document the significant Nanoarchaeota 16S rRNA gene diversity in this lake and firmly establish a terrestrial clade distinct from the marine Nanoarcheota as well as from other geographical locations.

  1. Territorio y gobernabilidad ambiental: análisis y reflexiones para el turismo de sol y playa en el litoral marítimo de la provincia de Buenos Aires

    OpenAIRE

    2010-01-01

    El impacto del turismo de sol y playa en el litoral marítimo de la Provincia de Buenos Aires; Argentina, necesita una caracterización y análisis en relación con la construcción del territorio y las transformaciones en el paisaje y en el ambiente ocurridas en sus costas. El objetivo principal de este trabajo será establecer una aproximación teórica y epistemológica para el estudio de la evolución histórica, el estado de sus playas, el riesgo de erosión marina, el avance del medio construido en...

  2. Impacto de la luz artificial sobre la anidación de la tortuga marina Dermochelys coriacea (Testudines: Dermochelyidae, en playa Cipara, Venezuela

    Directory of Open Access Journals (Sweden)

    María Rondón Médicci

    2009-09-01

    Full Text Available En Playa Cipara, Península de Paria, Venezuela, se evaluó el impacto de la luz artificial sobre la anidación de la tortuga cardón. Se estimó el número de anidaciones y su distribución espacial a lo largo de la playa entre los años sin y con iluminación artificial y entre segmentos de playa iluminada y oscura. Se hicieron entrevistas a los residentes para conocer su percepción sobre el impacto de la luz artificial hacia las tortugas marinas. Entre el 2000 y 2005 se registraron 1 217 salidas de tortuga cardón; con 1 056 nidos. El número de nidos con huevos dependió significativamente del año (p=0.035 al igual que el número de nidos totales (p=0.015. En los años previos a la electricidad (2000-2003 se observaron 743 salidas, de las cuales 661 con nido y 374 nidadas confirmadas. En los dos años (2004-2005 con iluminación artificial, se contaron 474 salidas con 395 nidos y 232 nidadas. La proporción de salidas con construcción de nido disminuyó significativamente (p=0.005 en los años con luz eléctrica, pero no varió el éxito de desove (p=0.402. No se encontró diferencia significativa entre el número de salidas por metro de playa en los sectores oscuros y los iluminados (p=0.244, ni entre el número de nidos construidos (p=0.379, ni entre las anidaciones con desove (p=0.516. Tampoco en la proporción de las salidas totales que constituyeron anidaciones (p=0.067 entre los sectores iluminados y oscuros, ni en la proporción de nidos exitosos (p=0.833. El volumen medio de arena por metro de playa fue mayor en La Peña, Cipara y La Remate y menor en Varadero (pImpact of artificial light on nesting in the leatherback turtle Dermochelys coriacea (Testudines: Dermochelyidae at Cipara beach, Venezuela. The number of Leatherback turtle nests and their spatial distribution was compared between years with and without artificial light, and between dark and lighted beach segments, in Cipara Beach, Paria Peninsula, Venezuela. Residents

  3. Dispersión espacial de Plicopurpura patula pansa en playas rocosas del estado de Guerrero, México Spatial pattern of Plicopurpura patula pansa,in rocky shores of Guerrero, México

    Directory of Open Access Journals (Sweden)

    Sergio García-Ibáñez

    2007-10-01

    Full Text Available Plicopurpura patula pansa es un caracol carnívoro característico de las costas rocosas del Pacífico mexicano. Presenta una glándula hipobraquial que secreta un fluido que adquiere una coloración púrpura en presencia de oxígeno y luz solar. Se determinó el arreglo espacial del caracol en playas que difieren en cuanto al tipo de sustrato, exposición al oleaje y pendiente de playa. Se calculó entre 0.1522 y 0.5435. Las menores fluctuaciones del Ip se presentaron en 5 playas que tienen en común sustratos fijos, gran cantidad de grietas y oquedades. Las mayores fluctuaciones correspondieron a 4 playas con sustratos móviles, como los cantos rodados.Plicopurpura patula pansa is a carnivore snail common of the Mexican Pacific rocky shores. Its hypobranchial gland produces a secretion that, in the presence of oxygen and sunlight, becomes purple. We determined the spatial distribution of the snail on beaches that differ in substratum, wave exposure, and the degree substratum’s inclination. The average snail density was calculated. Using the Morisita index (Id and the Morisita standardized index (Ip, we found that in 96.3% of the samples taken, the snails were distributed according to a patchy distribution. The rest of the time, their distribution was random. The I index oscillated between 0.1522 and 0.5435. Smaller fluctuations of the I index were observed in 5 beaches with substrata that were more stable and had a larger number of cracks and crevices than those on beaches with mobile substrata, such as rolled rocks.

  4. Implementación de sistemas de gestión integral sustentable para destinos turísticos, caso de estudio Parque Nacional Natural Utría, playa La Aguada – Colombia

    Directory of Open Access Journals (Sweden)

    Fernando Gutiérrez-Fernández

    2016-03-01

    Full Text Available En el presente proyecto se diseñó e implementó un sistema de gestión integral sustentable para playa La Aguada, en tres niveles de gestión: estratégico, táctico y operacional; ya que se comparó dicha playa con una organización. Para el diseño del sistema, el primer paso fue determinar los requisitos establecidos en la NTS TS 001-2, que es la norma correspondiente en Colombia a la certificación de destinos turísticos de playa. Esta certificación busca mejorar, no solo las condiciones en el ámbito ambiental, sino que exista una transversalidad entre el componente ambiental, el socio-cultural, el económico y el de seguridad, contribuyendo al progreso y al mejoramiento de la calidad de vida de la comunidad anfitriona que se involucra directamente con la actividad del turismo. Playa La Aguada, se encuentra ubicada en el Parque Nacional Natural de Utría en el Departamento de Choco – Colombia y como destino turístico, tiene un principal atractivo que es el avistamiento de ballenas Jorobadas o Yubartas (Megaptera novaeangliae Sin embargo, en los últimos años esta actividad se ha visto complementada por la realización de otro tipo de actividades eco turísticas, para lo cual la Unidad Administrativa Especial del Sistema de Parques Nacionales Naturales ha construido cabañas de alojamiento y un centro de visitantes. Por lo que esta se ha convertido en el lugar donde se recibe la mayor cantidad de visitantes, en el área natural y cuyo flujo se da durante todo el año; de manera que es necesario trabajar en su organización, buscando que el turismo no se convierta a futuro en una actividad perjudicial.

  5. Flood-inundation maps for Lake Champlain in Vermont and in northern Clinton County, New York

    Science.gov (United States)

    Flynn, Robert H.; Hayes, Laura

    2016-06-30

    Digital flood-inundation maps for an approximately100-mile length of Lake Champlain in Addison, Chittenden, Franklin, and Grand Isle Counties in Vermont and northern Clinton County in New York were created by the U.S. Geological Survey (USGS) in cooperation with the International Joint Commission (IJC). The flood-inundationmaps, which can be accessed through the International Joint Commission (IJC) Web site at http://www.ijc.org/en_/, depict estimates of the areal extent flooding correspondingto selected water levels (stages) at the USGS lake gage on the Richelieu River (Lake Champlain) at Rouses Point, N.Y. (station number 04295000). In this study, wind and seiche effects (standing oscillating wave with a long wavelength) were not taken into account and the flood-inundation mapsreflect 11 stages (elevations) for Lake Champlain that are static for the study length of the lake. Near-real-time stages at this lake gage, and others on Lake Champlain, may be obtained on the Internet from the USGS National Water Information System at http://waterdata.usgs.gov/ or the National Weather Service Advanced Hydrologic Prediction Service at http:/water.weather.gov/ahps/, which also forecasts flood hydrographs at the Richelieu River (Lake Champlain) at Rouses Point.Static flood boundary extents were determined for LakeChamplain in Addison, Chittenden, Franklin, and Grand Isle Counties in Vermont and northern Clinton County in New York using recently acquired (2013–2014) lidar (light detection and ranging) and may be referenced to any of the five USGS lake gages on Lake Champlain. Of these five lakgages, USGS lake gage 04295000, Richelieu River (Lake Champlain) at Rouses Point, N.Y., is the only USGS lake gage that is also a National Weather Service prediction location. Flood boundary extents for the Lake Champlain static flood-inundation map corresponding to the May 201 flood(103.2 feet [ft], National Geodetic Vertical Datum [NGVD] 29) were evaluated by comparing these boundary

  6. Can lake sensitivity to desiccation be predicted from lake geometry?

    Science.gov (United States)

    Torabi Haghighi, Ali; Menberu, Meseret Walle; Aminnezhad, Mousa; Marttila, Hannu; Kløve, Bjørn

    2016-08-01

    Declining lake levels (Aral Sea syndrome) can be caused by changes in climate, increased water use or changed regulation patterns. This paper introduces a novel lake geometry index (LGI) to quantify lake hydrological characteristics. The index was developed using a large representative dataset of lake hypsographic characteristics from 152 lakes and man-made reservoirs. Using the LGI index, lakes can be classified into five groups: groups 1-4 when LGI is 0.5-2.5, 2.5-4.5, 4.5-6.5 and 6.5-8.5, respectively, and group 5 when LGI is >8.5. Naturally shallow and vast lakes and wetlands fall into the first group and deep man-made reservoirs in narrow valleys are in group 5. The response of three different lake systems (LGI 0.75, 2.75 and 6.5) to different water flow scenarios was then simulated using the water balance equation. From this, the index 'potential lake area' (Apot) was developed to show lake responses to changed hydro-climatological conditions. Apot and LGI can be used to classify lakes into open or closed systems. Simulations showed that lakes with low LGI have a shorter response time to flow and climate changes. As a result, the impact of water balance restoration is faster for lakes with low LGI than for lakes with high LGI. The latter are also more vulnerable to climate variation and change.

  7. Playa de Varadero, península de Hicacos, Cuba: formación y evolución de su relieve y experiencias ambientales de su regeneración artificial

    Directory of Open Access Journals (Sweden)

    José Ramón Hernández Santana

    2002-01-01

    Full Text Available Uno de los sistemas más frágiles de la superficie terrestre lo constituye el litoral, fundamentalmente en sus sectores acumulativos, como las playas. Las regeneraciones artificiales, como los vertimientos de arena, representan una de las vías para su enriquecimiento sedimentario y estabilidad temporal, propicias para su protección medioambiental y desarrollo sustentable. Este trabajo amplía los conocimientos esenciales sobre la estructura, morfología, morfometría, génesis y dinámica del relieve peninsular de Hicacos, en particular en su sector más septentrional, para su uso y manejo optimizado; propone un modelo evolutivo de su consolidación geomorfológica; presenta y trasmite las experiencias ambientales del vertimiento de arena de la playa de Varadero de 1998, como medida regenerativa cardinal de la recuperación de la playa; y dicta un conjunto de medidas preventivas y correctivas, que favorecen la estabilidad de las condiciones geomorfológicas, en armonía con las obras hoteleras y de servicios construidas, en construcción y proyectadas.

  8. Eva en el Paraíso: La construcción y representación del cuerpo femenino en la playa como espacio turístico en Costa Rica

    Directory of Open Access Journals (Sweden)

    Esteban Barboza Núñez

    2016-10-01

    Full Text Available El artículo analiza la representación del cuerpo femenino como destino turístico, en la promoción de las playas en Costa Rica. Se hace un esbozo del estatus de la figura femenina en el imaginario androcéntrico occidental, desde sus raíces judeocristianas y de pensamiento clásico, hasta el advenimiento de la modernidad. Se reseñan postulados acerca del estatus del cuerpo femenino y la forma en que se construye en las representaciones gráficas; se parte de que la manera en que el cuerpo femenino es representado en la publicidad, enfocada a atraer turistas a la playa, le genera una doble otredad. La primera como mujer, cuyo físico es controlado por un imaginario androcéntrico que lo usa cual Eva-sirena, que tienta y atrae al posible visitante. La segunda como elemento que recrea una fantasía de exploración colonial de una playa prístina y “virginal”, y que la aleja de la modernidad racional cartesiana, en la cual la mente se impone a un cuerpo que debe ser controlado y domesticado por la razón.

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

    Energy Technology Data Exchange (ETDEWEB)

    Sienkiewicz, Elwira, E-mail: esienkie@twarda.pan.pl; Gąsiorowski, Michał, E-mail: mgasior@twarda.pan.pl

    2016-07-01

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

  10. Halls Lake 1990

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Salt marsh habitats along the shoreline of Halls Lake are threatened by wave erosion, but the reconstruction of barrier islands to reduce this erosion will modify or...

  11. Sunk Lake Natural Area

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The Sunk Lake Natural Area Management Plan guides the long-range development of the Natural Area by identifying and integrating appropriate habitats, management...

  12. Lake Transect : 1986

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This document summarizes transect surveys that were done at four different lakes on St. Vincent National Wildlife Refuge in 1986. Lists of the plant species found at...

  13. Lake Transect : 1988

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This document summarizes transect surveys that were done at four different lakes on St. Vincent National Wildlife Refuge in 1988. Lists of the plant species found at...

  14. Lake Transect : 1989

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This document summarizes transect surveys that were done at four different lakes on St. Vincent National Wildlife Refuge in 1989. Lists of the plant species found...

  15. History of Lake Andes

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Information about the history and management of Lake Andes is compiled in this report. It is intended to help future refuge managers become acquainted with the...

  16. Lake Level Reconstructions

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Records of past lake levels, mostly related to changes in moisture balance (evaporation-precipitation). Parameter keywords describe what was measured in this data...

  17. Great Lakes Ice Charts

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Charts show ice extent and concentration three times weekly during the ice season, for all lakes except Ontario, from the 1973/74 ice season through the 2001/2002...

  18. Directly dated MIS 3 lake-level record from Lake Manix, Mojave Desert, California, USA

    Science.gov (United States)

    Reheis, Marith; Miller, David M.; McGeehin, John P.; Redwine, Joanna R.; Oviatt, Charles G.; Bright, Jordon E.

    2015-01-01

    An outcrop-based lake-level curve, constrained by ~ 70 calibrated 14C ages on Anodonta shells, indicates at least 8 highstands between 45 and 25 cal ka BP within 10 m of the 543-m upper threshold of Lake Manix in the Mojave Desert of southern California. Correlations of Manix highstands with ice, marine, and speleothem records suggest that at least the youngest three highstands coincide with Dansgaard–Oeschger (D–O) stadials and Heinrich events 3 and 4. The lake-level record is consistent with results from speleothem studies in the Southwest that indicate cool wet conditions during D–O stadials. Notably, highstands between 43 and 25 ka apparently occurred at times of generally low levels of pluvial lakes farther north as interpreted from core-based proxies. Mojave lakes may have been supported by tropical moisture sources during oxygen-isotope stage 3, perhaps controlled by southerly deflection of Pacific storm tracks due to weakening of the sea-surface temperature gradient in response to North Atlantic climate perturbations.

  19. Chase Lake Wetland Management District, Chase Lake National Wildlife Refuge, Chase Lake Prairie Project: Annual narrative report: 1997

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Chase Lake WMD, Chase Lake NWR, Chase Lake Prairie Project, and Halfway Lake NWR outlines Refuge accomplishments during the 1997...

  20. Is Lake Tahoe Terminal?

    Science.gov (United States)

    Coats, R. N.; Reuter, J.; Heyvaert, A.; Lewis, J.; Sahoo, G. B.; Schladow, G.; Thorne, J. H.

    2014-12-01

    Lake Tahoe, an iconic ultra-oligotrophic lake in the central Sierra Nevada, has been studied intensively since 1968, with the goal of understanding and ultimately controlling its eutrophication and loss of clarity. Research on the lake has included a) periodic profiles of primary productivity, nutrients, temperature, and plankton; b) Secchi depth; c) nutrient limitation experiments; d) analysis of sediment cores; e) radiocarbon dating of underwater in-place tree stumps; g) analysis of long-term temperature trends. Work in its watershed has included a) monitoring of stream discharge, sediment and nutrients at up to 20 stream gaging stations; b) monitoring of urban runoff water quality at selected sites; c) development of a GIS data base, including soils, vegetation, and land use. Based on these studies, we know that a) primary productivity in the lake is limited by phosphorus, and continues to increase; b) the loss of clarity continues, but at a declining rate; c) the lake has been warming since 1970, and its resistance to deep mixing is increasing; d) historically the lake level drops below the outlet elevation about one year in seven; e) 6300 to 4300 yrs BP lake level was below the present outlet elevation long enough for large trees to grow; f) the date of the peak snowmelt runoff is shifting toward earlier dates; g) after accounting for annual runoff, loads of nutrients and suspended sediment have declined significantly in some basin streams since 1980. Downscaled outputs from GCM climatic models have recently been used to drive hydrologic models and a lake clarity model, projecting future trends in the lake and watersheds. Results show a) the temperature and thermal stability will likely continue to increase, with deep mixing shutting down in the latter half of this century; b) the lake may drop below the outlet for an extended period beginning about 2085; c) the annual snowpack will continue to decline, with earlier snowmelt and shift from snowfall to rain; d

  1. WHISKER LAKE WILDERNESS, WISCONSIN.

    Science.gov (United States)

    Schulz, Klaus J.

    1984-01-01

    The mineral-resource potential of the Whisker Lake Wilderness in northeastern Wisconsin was evaluated. Only a strip along the southwest corner of the wilderness is assessed as having probable mineral-resource potential. If mineral deposits exist, they probably are of the massive sulfide type. The geologic terrain precludes the presence of fossil fuel resources. Sand and gravel and peat in swampy lowlands are the only resources of the Whisker lake Wilderness.

  2. Development of a new platform for airborne measurements of atmospheric CO2 and CH4 and comparison with GOSAT measurements at Railroad Valley playa, Nevada

    Science.gov (United States)

    Tadic, J.; Loewenstein, M.; Iraci, L. T.; Gore, W.; Schiro, K. A.; Olson, R. A.; Sheffner, E. J.; Yates, E. L.

    2011-12-01

    Measurements of carbon dioxide (CO2) play an important role in understanding the global carbon cycle and its contribution to global warming. In recent years methane (CH4) has received increasing attention as the second most important anthropogenic greenhouse gas because of the high uncertainty of its sources and sinks. Aircraft measurements of greenhouse gases are essential for observations in the free troposphere and lower stratosphere to better understand changes at regional and continental scales. Recently new types of high-accuracy analyzers based on cavity-ring down spectroscopy have become available for use on aircraft. One of them, Picarro 2301-m, was remodeled and adapted for use outside the cabin of an Alpha Jet. In this unique attempt, the instrument was redesigned from a single unit to multiple units that fit inside the Alpha jet wing pod, with special emphasis on internal thermal management. After remodeling, the platform was tested in a laboratory, in a chamber with variable pressure and temperature, and in the field. This newly developed platform exhibits several important characteristics: the modular structure of the platform allows usage of other instruments simultaneously, the platform is capable of measuring both vertical and horizontal profiles of CO2 and CH4, and it is very insensitive to flight maneuvers. The new platform was used on 22-26th of June, 2011, to create spatial and temporal profiles of CO2 and CH4 over a playa in Railroad Valley, Nevada, USA. The playa is a flat, dry lakebed with virtually no vegetation, approximately 15 km x 15 km in size, 1434 m in elevation and 110 km southwest of the nearest city (Ely, Nevada). The time and location of flights were selected to coincide with the overpass of Greenhouse Gases Observing Satellite (GOSAT). Airborne (Alpha Jet) in-situ measurements of CO2 and CH4 were collected to support the vicarious calibration experiment to validate column-averaged dry air mole fractions of CO2 and CH4 (XCO2 and

  3. Beach erosion and nest site selection by the leatherback sea turtle Dermochelys coriacea (Testudines: Dermochelyidae and implications for management practices at Playa Gandoca, Costa Rica

    Directory of Open Access Journals (Sweden)

    Matthew J Spanier

    2010-12-01

    Full Text Available Leatherback sea turtles (Dermochelys coriacea nest on dynamic, erosion-prone beaches. Erosive processes and resulting nest loss have long been presumed to be a hindrance to clutch survival. In order to better understand how leatherbacks cope with unstable nesting beaches, I investigated the role of beach erosion in leatherback nest site selection at Playa Gandoca, Costa Rica. I also examined the potential effect of nest relocation, a conservation strategy in place at Playa Gandoca to prevent nest loss to erosion, on the temperature of incubating clutches. I monitored changes in beach structure as a result of erosion at natural nest sites during the time the nest was laid, as well as in subsequent weeks. To investigate slope as a cue for nest site selection, I measured the slope of the beach where turtles ascended from the sea to nest, as well as the slopes at other random locations on the beach for comparison. I examined temperature differences between natural and relocated nest sites with thermocouples placed in the sand at depths typical of leatherback nests. Nests were distributed non-randomly in a clumped distribution along the length of the beach and laid at locations that were not undergoing erosion. The slope at nest sites was significantly different than at randomly chosen locations on the beach. The sand temperature at nest depths was significantly warmer at natural nest sites than at locations of relocated nests. The findings of this study suggest leatherbacks actively select nest sites that are not undergoing erosive processes, with slope potentially being used as a cue for site selection. The relocation of nests appears to be inadvertently cooling the nest environment. Due to the fact that leatherback clutches undergo temperaturedependent sex determination, the relocation of nests may be producing an unnatural male biasing of hatchlings. The results of this study suggest that the necessity of relocation practices, largely in place to

  4. Pesticide Impact Assessment in Tule Lake and Lower Klamath National Wildlife Refuges, 1998 - 2000 Growing Season

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Tule Lake and the adjacent Lower Klamath National Wildlife Refuges (TLNWR and LKNWR) serve as key spring/fall staging and overwintering areas for Pacific Flyway...

  5. Spatial distribution and temporal development of high-mountain lakes in western Austria

    Science.gov (United States)

    Merkl, Sarah; Emmer, Adam; Mergili, Martin

    2015-04-01

    elevation at the cost of moraine-dammed lakes. Multi-temporal analysis of selected near-glacial lakes reveals cases where lakes have appeared as proglacial lakes, but lost contact to the glacier within few decades or even years, or have even been decoupled from the glacial water supply. This goes hand in hand with rapid changes of lake shape and size, with merging or separating of lakes, and with the disappearance of short-lived lakes or lake systems. Consequently, we distinguish three stages of lake development: (a) a pro-glacial, (b) a periglacial and (c) a non-glacial stage. The dynamics - and also the susceptibility of a lake to sudden drainage - decrease substantially from (a) to (c). Lakes in the stages (a) and (b) are less prominent in our study area, compared to other glacierized high-mountain regions, leading us to the conclusion that (1) the current threat to the population by GLOFs is lower but (2) the future development of emerging lakes has to be monitored carefully.

  6. Resilience and Restoration of Lakes

    Directory of Open Access Journals (Sweden)

    Kathryn L. Cottingham

    1997-06-01

    Full Text Available Lake water quality and ecosystem services are normally maintained by several feedbacks. Among these are nutrient retention and humic production by wetlands, nutrient retention and woody habitat production by riparian forests, food web structures that cha nnel phosphorus to consumers rather than phytoplankton, and biogeochemical mechanisms that inhibit phosphorus recycling from sediments. In degraded lakes, these resilience mechanisms are replaced by new ones that connect lakes to larger, regional economi c and social systems. New controls that maintain degraded lakes include runoff from agricultural and urban areas, absence of wetlands and riparian forests, and changes in lake food webs and biogeochemistry that channel phosphorus to blooms of nuisance al gae. Economic analyses show that degraded lakes are significantly less valuable than normal lakes. Because of this difference in value, the economic benefits of restoring lakes could be used to create incentives for lake restoration.

  7. Is Lake Chabot Eutrophic?

    Science.gov (United States)

    Pellegrini, K.; Logan, J.; Esterlis, P.; Lew, A.; Nguyen, M.

    2013-12-01

    Introduction/Abstract: Lake Chabot is an integral part of the East Bay watershed that provides habitats for animals and recreation for humans year-round. Lake Chabot has been in danger of eutrophication due to excessive dumping of phosphorous and nitrogen into the water from the fertilizers of nearby golf courses and neighboring houses. If the lake turned out to be eutrophified, it could seriously impact what is currently the standby emergency water supply for many Castro Valley residents. Eutrophication is the excessive richness of nutrients such as nitrogen and phosphorus in a lake, usually as a result of runoff. This buildup of nutrients causes algal blooms. The algae uses up most of the oxygen in the water, and when it dies, it causes the lake to hypoxify. The fish in the lake can't breathe, and consequently suffocate. Other oxygen-dependant aquatic creatures die off as well. Needless to say, the eutrophication of a lake is bad news for the wildlife that lives in or around it. The level of eutrophication in our area in Northern California tends to increase during the late spring/early summer months, so our crew went out and took samples of Lake Chabot on June 2. We focused on the area of the lake where the water enters, known on the map as Honker Bay. We also took readings a ways down in deeper water for comparison's sake. Visually, the lake looked in bad shape. The water was a murky green that glimmered with particulate matter that swirled around the boat as we went by. In the Honker Bay region where we focused our testing, there were reeds bathed in algae that coated the surface of the lake in thick, swirling patterns. Surprisingly enough, however, our test results didn't reveal any extreme levels of phosphorous or nitrogen. They were slightly higher than usual, but not by any significant amount. The levels we found were high enough to stimulate plant and algae growth and promote eutrophication, but not enough to do any severe damage. After a briefing with a

  8. Tewaukon – Clouds LakeLake Elsie – Storm Lake and Wild Rice Refuges Narrative Reports : 1939-1956 : From Sand Lake National Wildlife Refuge

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — These narrative reports summarize refuge activities from 1939 to 1956 for Lake Tewaukon Refuge, Clouds Lake Refuge, Lake Elsie Refuge, Storm Lake Refuge, Wild Rice...

  9. TOXAPHENE STUDY OF GREAT LAKES TRIBUTARY SEDIMENTS

    Science.gov (United States)

    The Product is the paper "Pulp and Paper Mills as Sources of Toxaphene to Lake Superior and Northern Lake Michigan" published in the Journal of Great Lakes Research, 25(2):383-394 International Association of Great Lakes 1999.

  10. Glacial lake inventory and lake outburst potential in Uzbekistan.

    Science.gov (United States)

    Petrov, Maxim A; Sabitov, Timur Y; Tomashevskaya, Irina G; Glazirin, Gleb E; Chernomorets, Sergey S; Savernyuk, Elena A; Tutubalina, Olga V; Petrakov, Dmitriy A; Sokolov, Leonid S; Dokukin, Mikhail D; Mountrakis, Giorgos; Ruiz-Villanueva, Virginia; Stoffel, Markus

    2017-08-15

    Climate change has been shown to increase the number of mountain lakes across various mountain ranges in the World. In Central Asia, and in particular on the territory of Uzbekistan, a detailed assessment of glacier lakes and their evolution over time is, however lacking. For this reason we created the first detailed inventory of mountain lakes of Uzbekistan based on recent (2002-2014) satellite observations using WorldView-2, SPOT5, and IKONOS imagery with a spatial resolution from 2 to 10m. This record was complemented with data from field studies of the last 50years. The previous data were mostly in the form of inventories of lakes, available in Soviet archives, and primarily included localized in-situ data. The inventory of mountain lakes presented here, by contrast, includes an overview of all lakes of the territory of Uzbekistan. Lakes were considered if they were located at altitudes above 1500m and if lakes had an area exceeding 100m(2). As in other mountain regions of the World, the ongoing increase of air temperatures has led to an increase in lake number and area. Moreover, the frequency and overall number of lake outburst events have been on the rise as well. Therefore, we also present the first outburst assessment with an updated version of well-known approaches considering local climate features and event histories. As a result, out of the 242 lakes identified on the territory of Uzbekistan, 15% are considered prone to outburst, 10% of these lakes have been assigned low outburst potential and the remainder of the lakes have an average level of outburst potential. We conclude that the distribution of lakes by elevation shows a significant influence on lake area and hazard potential. No significant differences, by contrast, exist between the distribution of lake area, outburst potential, and lake location with respect to glaciers by regions. Copyright © 2017 Elsevier B.V. All rights reserved.

  11. Requerimientos y disponibilidad de arenas parala defensa de las playas de Necochea y Lobería Requirements and availability of sand for theprotection of Nechochea and Lobería beaches

    Directory of Open Access Journals (Sweden)

    Federico Isla

    2009-11-01

    Full Text Available La costa de Lobería y Necochea se caracteriza poracantilados y playas de escaso desarrollo. La desembocadura del río QuequénGrande alteraba la línea de costa. La construcción de las escolleras del puertode Quequén indujo una gran acumulación de arena en el sector de Necochea, y uncrítico proceso erosivo de los acantilados y en las playas del este. El anchode las playas se reduce de 300 m en el oeste a sólo 40-60 m hacia el este.Considerando la escasez generalizada de arena, las playas del este son las quetienen mayor variabilidad sedimentaria. Las mayores variaciones en los balancesde arena fueron originadas por actividades humanas. Las olas provenientes delE, SE y S proyectan mayor energía en este sector oriental. Por otro lado, lossectores infralitorales de estas playas tienen poca disponibilidad de arena. Lamayor abundancia de arena fina ha sido reconocida hacia el balneario Necochea.El río Quequén Grande tiene un significativo efecto sobre la dinámica delestuario durante las crecidas originadas por eventos ENSO, aunque la sedimentaciónestá dominada por aportes de limo.Thecoast of Lobería and Necochea is characterized by cliffsand narrow beaches. Theinlet of the Quequén Grande river used to alter the coastline. The constructionof jetties related to the Quequén Harbour induced huge accumulations of sandtowards Necochea, and a critic erosive process of cliff and beach to the east.Beach width reduces from 300 m at the west to 40-60 m to the east. Consideringregional sand scarcity, the eastern beaches are characterized by more sandvariability. Greater variations in the sand balance were assigned to humanactivity. Waves coming from the E, SE and S deliver more energy along thiseastern sector. On the other hand, submerged zones of these beaches have lessavailability of sand. Greater availability of fine sand was recognized towardsNecochea. The Quequén Grande river has much effect on the estuarine dynamicsduring ENSO

  12. Evidence of Lake Trout reproduction at Lake Michigan's mid-lake reef complex

    Science.gov (United States)

    Janssen, J.; Jude, D.J.; Edsall, T.A.; Paddock, R.W.; Wattrus, N.; Toneys, M.; McKee, P.

    2006-01-01

    The Mid-Lake Reef Complex (MLRC), a large area of deep (> 40 m) reefs, was a major site where indigenous lake trout (Salvelinus namaycush) in Lake Michigan aggregated during spawning. As part of an effort to restore Lake Michigan's lake trout, which were extirpated in the 1950s, yearling lake trout have been released over the MLRC since the mid-1980s and fall gill net censuses began to show large numbers of lake trout in spawning condition beginning about 1999. We report the first evidence of viable egg deposition and successful lake trout fry production at these deep reefs. Because the area's existing bathymetry and habitat were too poorly known for a priori selection of sampling sites, we used hydroacoustics to locate concentrations of large fish in the fall; fish were congregating around slopes and ridges. Subsequent observations via unmanned submersible confirmed the large fish to be lake trout. Our technological objectives were driven by biological objectives of locating where lake trout spawn, where lake trout fry were produced, and what fishes ate lake trout eggs and fry. The unmanned submersibles were equipped with a suction sampler and electroshocker to sample eggs deposited on the reef, draw out and occasionally catch emergent fry, and collect egg predators (slimy sculpin Cottus cognatus). We observed slimy sculpin to eat unusually high numbers of lake trout eggs. Our qualitative approaches are a first step toward quantitative assessments of the importance of lake trout spawning on the MLRC.

  13. Lake Morphometry for NHD Lakes in Ohio Region 5 HUC

    Data.gov (United States)

    U.S. Environmental Protection Agency — Lake morphometry metrics are known to influence productivity in lakes and are important for building various types of ecological and environmental models of lentic...

  14. Lake Morphometry for NHD Lakes in California Region 18 HUC

    Data.gov (United States)

    U.S. Environmental Protection Agency — Lake morphometry metrics are known to influence productivity in lakes and are important for building various types of ecological and environmental models of lentic...

  15. Lake Morphometry for NHD Lakes in Tennessee Region 6 HUC

    Data.gov (United States)

    U.S. Environmental Protection Agency — Lake morphometry metrics are known to influence productivity in lakes and are important for building various types of ecological and environmental models of lentic...

  16. SATELLITE LAKES OF LAKE VICTORIA BASIN (TANZANIAN SIDE)

    African Journals Online (AJOL)

    Studies on phytoplankton species diversity and abundance were carried out in 8 selected satellite lakes within the Lake ... species of blue green algae such as Spirulina spp. are sources of ... scientific and conservation interests. This study ...

  17. Spatiotemporal patterns of high-mountain lakes and related hazards in western Austria

    Science.gov (United States)

    Emmer, Adam; Merkl, Sarah; Mergili, Martin

    2015-10-01

    Climate-induced environmental changes are triggering the dynamic evolution of high-mountain lakes worldwide, a phenomenon that has to be monitored in terms of lake outburst hazards. We analyzed the spatial distribution and recent temporal development of high-mountain lakes in a study area of 6139 km2, covering the central European Alps over most of the province of Tyrol and part of the province of Salzburg in western Austria. We identified 1024 natural lakes. While eight lakes are ice-dammed, one-third of all lakes are located in the immediate vicinity of recent glacier tongues, half of them impounded by moraines, half by bedrock. Two-thirds of all lakes are apparently related to LIA or earlier glaciations. One landslide-dammed lake was identified in the study area. The evolution of nine selected (pro)glacial lakes was analyzed in detail, using multitemporal remotely sensed images and field reconnaissance. Considerable glacier retreat led to significant lake growth at four localities, two lakes experienced stagnant or slightly negative areal trends, one lake experienced a more significant negative areal trend, and two lakes drained completely during the investigation period. We further (i) analyzed the susceptibility of selected lakes to glacial lake outburst floods (GLOFs), using two different methods; (ii) identified potential triggers and mechanisms of GLOFs; (iii) calculated possible flood magnitudes for predefined flood scenarios for a subset of the lakes; and (iv) delineated potentially impacted areas. We distinguished three phases of development of bedrock-dammed lakes: (a) a proglacial, (b) a glacier-detached, and (c) a nonglacial phase. The dynamics - and also the susceptibility of a lake to GLOFs - decrease substantially from (a) to (c). Lakes in the stages (a) and (b) are less prominent in our study area, compared to other glacierized high-mountain regions, leading us to the conclusion that (i) the current threat to the population by GLOFs is lower but

  18. Organic matter degradation in Lake Baikal - a sediment trap study

    DEFF Research Database (Denmark)

    Schubert, Carsten J.; Niggemann, Jutta; Lomstein, Bente Aagaard

    Lake Baikal offers a unique opportunity to study water column processes in a freshwater system with conditions similar to oceanic systems, e. g. great water depth and oxygenated water column. Investigations on sediment trap material provide information on the early stages of organic matter...... and composition of amino acids and fatty acids. The extent of organic matter degradation in the water column of Lake Baikal is reflected in the fluxes of total organic carbon, chlorins, amino acids, and fatty acids at different water depths. In line with earlier studies in marine systems, the labile compounds......, and the Fatty Acid Index [2]. All indicators showed consistent trends, indicating that the diagenetic stage of the sediment trap material increased with increasing water depth. This study of sediment trap material from Lake Baikal provided interesting insights in organic matter degradation in this unique...

  19. La cartografía bibliográfica y la memoria emblemática Playa Ancha, Valparaíso

    Directory of Open Access Journals (Sweden)

    Marjorie Andrea Mardones Leiva

    2016-12-01

    Full Text Available Este estudio propone un análisis para el estudio de la memoria emblemática del territorio de Playa Ancha, Valparaíso, basándose en una revisión bibliográfica situada. Su objetivo principal es reconocer los discursos que han colaborado en la construcción, articulación y cristalización del imaginario social de la localidad a partir de su producción bibliográfica: temáticas recurrentes, agentes discursivos oficiales y disidentes, prácticas sociales, entre otros. Esta investigación pone en crisis la tendencia de los estudios bibliométricos actuales que se han dedicado principalmente al análisis de información para entidades educacionales o de producción científica nacional, dejando atrás aspectos tan importantes como es el espacio, tiempo, lugar (Sousa-Santos, 1991 y su relación con el día a día del ciudadano. Para representar los resultados del estudio, se han utilizado gráficos y cartografías, destacando la relación entre territorio y bibliografía.

  20. Use RUSLE2 model to assess the impact of soil erosion on playa inundation and hydrophyte conditions in the Rainwater Basin, Nebraska.

    Science.gov (United States)

    Tang, Zhenghong; Gu, Yue; Jiang, Weiguo; Xue, Yuan; Bishop, Andy; LaGrange, Ted; Nugent, Eleanor

    2016-06-01

    Playas in the Rainwater Basin region in Nebraska are globally important wetlands that are continuously threatened by culturally accelerated sedimentation. Using annual habitat survey data and wetland vegetation inventories, inundation and hydrophyte community distributions were evaluated for properties under different types of conservation status. Annual soil erosion rates from surrounding watersheds were calculated to estimate sediment accumulated rates using the Revised Universal Soil Loss Equation 2 (RUSLE2). The slope-length component of the RUSLE2 was derived from 2009 light detection and ranging (LiDAR) data after the methods described by Van Remortel (Computers & Geosciences 30:1043-1053, 2004). Wetlands enrolled in conservation programs were inundated more and were dominated to a greater degree by hydrophytes than wetlands not enrolled in these programs. The mean estimated soil erosion rate at the Rainwater Basin landscape level was 4.67 tons/ha/year, and the mean estimated sediment accumulation depth for public watersheds was estimated as 0.19 cm/year. Without appropriate conservation actions, the current inundated acres and wetland acres growing hydrophytes would be further reduced by sediment accumulation. The results illustrated the importance of conservation programs to protect wetlands.

  1. Tendencias climáticas de las inundaciones costeras en el litoral Gibara-Playa Guardalavaca, provincia Holguín, Cuba

    Directory of Open Access Journals (Sweden)

    Axel Hidalgo Mayo

    2015-12-01

    Full Text Available Se presenta un estudio relacionado con las tendencias climáticas de las inundaciones costeras para el período 1960-2015 en el litoral Gibara-Playa Guardalavaca, provincia Holguín, Cuba. Los métodos empleados fueron la distribución de probabilidad de Poisson y los test de Mann-Kendall, Pettitt y Spearman. Los principales resultados alcanzados fueron el análisis de la tendencia estadística de la serie y el cálculo de los períodos de retorno. Se concluye que las inundaciones costeras para este litoral muestran una tendencia positiva a partir de 2007 y que el peligro de los eventos de inundación moderados y fuertes se ha duplicado. Los resultados obtenidos son aplicables en la elaboración de pronósticos a mediano y corto plazo, así como en la elaboración de planes de contingencia y acciones de manejo costero.

  2. Análisis del sistema defensivo de segunda línea en voley playa femenino en función del nivel de juego

    Directory of Open Access Journals (Sweden)

    GEMMA MARÍA GEA GARCÍA

    2014-03-01

    Full Text Available El objetivo principal de este estudio fue analizar las acciones defensivas de segunda línea en voley playa femenino, en función del nivel de juego exhibido por las parejas participantes. Se analizaron un total de 15 partidos, dentro de los cuales se registraron 856 secuencias defensivas completas en segunda línea. Para ello, se creó un instrumento observacional (sistema de categorías a través del cual se efectuó un registro sistemático de las acciones defensivas de segunda línea. Se realizó un estudio de confiabilidad para determinar el grado de concordancia inter e intraobservadores, llegando a alcanzar una concordancia entre los observadores > 0,80, lo que avala la calidad de datos. Tras el cruce de variables, los resultados obtenidos mostraron una diferencia significativa (x² de Pearson < 0,05, en cuanto a las acciones defensivas a emplear por las jugadoras. Sin embargo, las parejas no mostraron diferencias en el patrón de juego defensivo de segunda línea en función del nivel de juego.

  3. Incidence of variables in the Transfer of Tacit Knowledge of Marketing in the hotel sector of Playa del Carmen city, Mexico.

    Directory of Open Access Journals (Sweden)

    José Luis Zapata

    2017-01-01

    Full Text Available Esta investigación permitió validar un modelo de influencia de la intención de aprendizaje de market‑ ing, motivación personal y capacidad de absorción de conocimiento de marketing en la adquisición de conocimien‑ to tácito de marketing y esto a su vez en la transferencia de conocimiento tácito de marketing entre los empleados de pequeñas y medianas empresas hoteleras en la ciudad de Playa del Carmen, Quintana Roo, México. A través de una investigación cuantitativa y transversal, se integraron 229 empleados del sector hotelero. Los resultados mostraron que la motivación personal y la intención de aprender marketing intervienen positivamente en la adquisición de conocimiento tácito de marketing y, con influencia de la capacidad de absorción del conocimiento de marketing, impactan directamente la transferencia de conocimiento tácito de marketing.

  4. Widespread Lake Highstands in the Southernmost Andean Altiplano during Heinrich Event 1: Implications for the South American Summer Monsoon

    Science.gov (United States)

    Chen, C. Y.; McGee, D.; Quade, J.

    2014-12-01

    Speleothem-based oxygen isotope records provide strong evidence of anti-phased behavior of the northern and southern hemisphere summer monsoons during Heinrich events, but we lack rigorous constraints on the amount of wetting or drying occurring in monsoon regions. Studies centered on shoreline deposits of closed-basin lakes are well suited for establishing such quantitative controls on water balance changes by providing unequivocal evidence of lake volume variations. Here we present new dating constraints on the highstands of several high-altitude (3800-4350 m) paleolakes in the southern Andean Altiplano, an outlying arid region of the Atacama Desert stretching across the Chilean-Bolivian-Argentinian border east of the Andes (20-25°S). These lakes once occupied the closed basins where only phreatic playas, dry salars, and shallow ponds exist today. Initial U-Th dating of massive shoreline tufas reveals that these deposits are dateable to within ±150 to 300 yrs due to high U concentrations and low initial Th content (as indicated by high 230Th/232Th). Our U-Th and 14C dates show that lake highstands predominantly occur between 18.5 and 14.5 kyrs BP, coinciding with Heinrich Event 1 (HE1) and the expansion of other nearby lakes, such as Lake Titicaca. Because of their (1) location at the modern-day southwestern edge of the summer monsoon, (2) intact shoreline preservation, and (3) precise age control, these lakes may uniquely enable us to reconstruct the evolution of water balance (P-E) changes associated with HE1. Hydrologic modeling constrained by temperature estimates provided by local glacial records is used to provide bounds for past precipitation changes. We also examine North Atlantic cooling as the mechanism for these changes by comparing a compilation of S. American lake level records with various hosing experiments and transient climate simulations at HE1. Our results lend us confidence in expanding our U-Th work to other shoreline tufas in the

  5. Late Quaternary ostracode-based paleoenvironmental reconstructions from Lake Petén Itzá, Guatemala and Lake Chalco, central Mexico

    Science.gov (United States)

    Perez, L.; Lozano, S.; Caballero, M.; Brenner, M.; Schwalb, A.

    2013-05-01

    Modern and fossil ostracodes in lakes from central Mexico (Chalco) to lowland Guatemala (Petén Itzá) were used to infer paleoenvironmental conditions during the last 45 ka. Ostracode-based paleoenvironmental reconstruction from sediment cores in Lake Petén Itzá was based on a modern calibration data set from 63 water bodies in Guatemala, Mexico (Yucatán Peninsula) which provided information on the modern ecological preferences of 29 ostracode species. Statistical analysis indicated that lake water conductivity and chemical composition determine ostracode distributions on the Yucatán Peninsula and that lake level is a strong determinant of species distribution in Lake Petén Itzá. Transfer functions were applied to fossil species assemblages in long sediment cores from Lake Petén Itzá to infer past conductivity and lake level. Over the past 45 ka, ostracodes in Lake Petén Itzá were sensitive to fluctuations in lake water chemical composition and lake stage. Relative abundances of ostracode taxa and stable isotope values in their shells indicate large environmental changes from the LGM to deglaciation, and into the Holocene. The LGM was characterized by low species richness (n=4), dominance of benthic taxa, cold conditions and moderate to high lake levels. The deglaciation displayed higher species richness (n=6), dominance of nektobenthic taxa, and alternating dry and wet conditions, with low to relatively high lake levels. The Holocene was dominated by the deep-water ostracode Physocypria globula, indicating warmer temperatures and higher lake levels. Preliminary results from Lake Chalco sediment cores indicate ostracodes were scarce during the LGM and deglacial, but displayed higher abundances in older deposits. Ostracodes identified in the sediment record include Limnocythere sp., Candona patzcuaro and Darwinula stevensoni. The only species in common with the Lake Petén Itzá record is D. stevensoni. Deglacial species richness in Chalco (n=3) was lower

  6. Highly divergent mussel lineages in isolated Indonesian marine lakes

    Science.gov (United States)

    de Leeuw, Christiaan A.; Knegt, Bram; Maas, Diede L.; de Voogd, Nicole J.; Abdunnur; Suyatna, Iwan; Peijnenburg, Katja T.C.A.

    2016-01-01

    Marine lakes, with populations in landlocked seawater and clearly delineated contours, have the potential to provide a unique model to study early stages of evolution in coastal marine taxa. Here we ask whether populations of the mussel Brachidontes from marine lakes in Berau, East Kalimantan (Indonesia) are isolated from each other and from the coastal mangrove systems. We analyzed sequence data of one mitochondrial marker (Cytochrome Oxidase I (COI)), and two nuclear markers (18S and 28S). In addition, we examined shell shape using a geometric morphometric approach. The Indonesian populations of Brachidontes spp. harbored four deeply diverged lineages (14–75% COI corrected net sequence divergence), two of which correspond to previously recorded lineages from marine lakes in Palau, 1,900 km away. These four lineages also showed significant differences in shell shape and constitute a species complex of at least four undescribed species. Each lake harbored a different lineage despite the fact that the lakes are separated from each other by only 2–6 km, while the two mangrove populations, at 20 km distance from each other, harbored the same lineage and shared haplotypes. Marine lakes thus represent isolated habitats. As each lake contained unique within lineage diversity (0.1–0.2%), we suggest that this may have resulted from in situdivergence due to isolation of founder populations after the formation of the lakes (6,000–12,000 years before present). Combined effects of stochastic processes, local adaptation and increased evolutionary rates could produce high levels of differentiation in small populations such as in marine lake environments. Such short-term isolation at small spatial scales may be an important contributing factor to the high marine biodiversity that is found in the Indo-Australian Archipelago. PMID:27761314

  7. Highly divergent mussel lineages in isolated Indonesian marine lakes

    Directory of Open Access Journals (Sweden)

    Leontine E. Becking

    2016-10-01

    Full Text Available Marine lakes, with populations in landlocked seawater and clearly delineated contours, have the potential to provide a unique model to study early stages of evolution in coastal marine taxa. Here we ask whether populations of the mussel Brachidontes from marine lakes in Berau, East Kalimantan (Indonesia are isolated from each other and from the coastal mangrove systems. We analyzed sequence data of one mitochondrial marker (Cytochrome Oxidase I (COI, and two nuclear markers (18S and 28S. In addition, we examined shell shape using a geometric morphometric approach. The Indonesian populations of Brachidontes spp. harbored four deeply diverged lineages (14–75% COI corrected net sequence divergence, two of which correspond to previously recorded lineages from marine lakes in Palau, 1,900 km away. These four lineages also showed significant differences in shell shape and constitute a species complex of at least four undescribed species. Each lake harbored a different lineage despite the fact that the lakes are separated from each other by only 2–6 km, while the two mangrove populations, at 20 km distance from each other, harbored the same lineage and shared haplotypes. Marine lakes thus represent isolated habitats. As each lake contained unique within lineage diversity (0.1–0.2%, we suggest that this may have resulted from in situdivergence due to isolation of founder populations after the formation of the lakes (6,000–12,000 years before present. Combined effects of stochastic processes, local adaptation and increased evolutionary rates could produce high levels of differentiation in small populations such as in marine lake environments. Such short-term isolation at small spatial scales may be an important contributing factor to the high marine biodiversity that is found in the Indo-Australian Archipelago.

  8. Lake Michigan lake trout PCB model forecast post audit

    Science.gov (United States)

    Scenario forecasts for total PCBs in Lake Michigan (LM) lake trout were conducted using the linked LM2-Toxics and LM Food Chain models, supported by a suite of additional LM models. Efforts were conducted under the Lake Michigan Mass Balance Study and the post audit represents th...

  9. Diatom-inferred history of one of the northernmost Greenland lakes

    DEFF Research Database (Denmark)

    Ludikova, Anna; Olsen, Jesper; Kjær, Kurt H.

    , as well as physical and geochemical proxies was used to reconstruct the Holocene history of one of the small lakes located in Peary Land, northernmost Greenland, to decipher the environmental changes of the past. The diatom record of Bliss Lake (83°35'14''N 28°21'12''W, 17 m a.s.l.) reveals three main...... stages of the lake's development which is corroborated with other data. In the earliest stage dated back to the Early Holocene, the diatom record suggests a proglacial environment with meltwaters freshening a marine bay. After the glacier retreat around 9,400 cal yr BP, increased abundances of meso...

  10. Mono Lake Excursion Reviewed

    Science.gov (United States)

    Liddicoat, J. C.; Coe, R. S.

    2007-05-01

    The Mono Lake Excursion as recorded in the Mono Basin, CA, has an older part that is about negative 30 degrees inclination and about 300 degrees declination during low relative field intensity. Those paleomagnetic directions are closely followed by greater than 80 degrees positive inclination and east declination of about 100 degrees during higher relative field intensity. A path of the Virtual Geomagnetic Poles (VGPs) for the older part followed from old to young forms a large clockwise loop that reaches 35 degrees N latitude and is centered at about 35 degrees E longitude. That loop is followed by a smaller one that is counterclockwise and centered at about 70 degrees N latitude and 270 degrees E longitude (Denham & Cox, 1971; Denham, 1974; Liddicoat & Coe, 1979). The Mono Lake Excursion outside the Mono Basin in western North America is recorded as nearly the full excursion at Summer Lake, OR (Negrini et al., 1984), and as the younger portion of steep positive inclination/east declination in the Lahontan Basin, NV. The overall relative field intensity during the Mono Lake Excursion in the Lahontan Basin mirrors very closely the relative field intensity in the Mono Basin (Liddicoat, 1992, 1996; Coe & Liddicoat, 1994). Using 14C and 40Ar/39Ar dates (Kent et al., 2002) and paleoclimate and relative paleointensity records (Zimmerman et al., 2006) for the Mono Lake Excursion in the Mono Basin, it has been proposed that the Mono Lake Excursion might be older than originally believed and instead be the Laschamp Excursion at about 40,000 yrs B.P. (Guillou et al., 2004). On the contrary, we favor a younger age for the Mono Lake Excursion, about 32,000 yrs B.P., using the relative paleointensity in the Mono Basin and Lahontan Basin and 14C dates from the Lahontan Basin (Benson et al., 2002). The age of about 32,000 yrs B.P. is also in accord with the age (32,000- 34,000 yrs B.P.) reported by Channell (2006) for the Mono Lake Excursion at ODP Site 919 in the Irminger Basin

  11. Lake Erie Fish Community Data

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Lake Erie Biological Station (LEBS), located in Sandusky, Ohio, is a field station of the USGS Great Lakes Science Center (GLSC). LEBS is the primary federal agency...

  12. Crescent Lake Wilderness Reference Sheet

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Reference sheet includes information about Crescent Lake National Wildlife Refuge, and results of the public hearing for Crescent Lake Wilderness Proposal.

  13. Freshwater lake seabird surveys 2012

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The Alaska Peninsula/Becharof NWR complex hosts Becharof Lake, the largest lake within a National Wildlife Refuge system. In addition to this distinction, Becharof...

  14. Great Lakes Environmental Database (GLENDA)

    Data.gov (United States)

    U.S. Environmental Protection Agency — The Great Lakes Environmental Database (GLENDA) houses environmental data on a wide variety of constituents in water, biota, sediment, and air in the Great Lakes area.

  15. Functional microbiology of soda lakes

    NARCIS (Netherlands)

    Sorokin, D.Y.; Banciu, H.L.; Muyzer, G.

    2015-01-01

    Soda lakes represent unique permanently haloalkaline system. Despite the harsh conditions, they are inhabited by abundant, mostly prokaryotic, microbial communities. This review summarizes results of studies of main functional groups of the soda lake prokaryotes responsible for carbon, nitrogen and

  16. Changes in lake level and trophy at Lake Vrana, a large karstic lake on the Island of Cres (Croatia, with respect to palaeoclimate and anthropogenic impacts during the last approx. 16,000 years

    Directory of Open Access Journals (Sweden)

    Ante BARIĆ

    2000-08-01

    Full Text Available A multi-proxy approach study (cladocerans, diatoms, geochemistry, plant macrofossils, pollen, was performed on a sediment core from Lake Vrana (Vransko Jezero, a large and deep karstic lake on the northern Adriatic island of Cres, Croatia. Considerable lake-level changes occurred during the last approx. 16,000 years. The stratigraphic evidence suggests that periods of enhanced precipitation and the post-LGM rise in sea level were the main driving forces. The lake records indicate early human impacts. Sediment echo-sounding indicated that >25 m of lake sediments lies within the site, from which 5 m have been cored. Shallow lake stages occurred from 14.4 14C ky BP to early Holocene. Prior to Alleröd, interglacial sediments were redeposited, reflecting the influences of rising sea-level (forming a local groundwater barrier, a temporary increase in precipitation, and lake-level changes. There appears to be a hiatus in the sequence, for no sediments assignable to the Alleröd chronozone could be found. A discordance in the echo profile at the appropriate horizon in the sequence supports this interpretation. Groundwater level increased again at 10.6 ky BP (during Younger Dryas chronozone, a swamp vegetation formed, which gave way to a shallow lake. During the Preboreal chronozone, this freshwater lake persisted with fluctuating levels. The establishment and subsequent persistence of the present deep water lake at about 8.5 ky BP, correspond with findings of a pluvial period at the Dalmatian coast, which lasted from 8.4 to 6 ky BP. First human catchment disturbances were related to settlements of Neolithic or Bronze Age. The increase in summer drought, coupled with forest clearance during Illyrian times, are assumed to be responsible for the change towards present evergreen oak vegetation in the lake catchment. The intensification in land-use during Roman and post-Roman settlements caused a slight increase in the lake trophic level.

  17. Determinación de la secuencia de precipitación salina en la laguna de La Playa (Zaragoza, España. 1. Condiciones de equilibrio mineral y simulación teórica del proceso

    Directory of Open Access Journals (Sweden)

    Gómez, J.

    1999-04-01

    Full Text Available Neutral brines of the Na-Cl type from La Playa saline system reach extremely high concentrations (up to ionic strengths of 10 molal during the evaporative process. Ionic activities and mineral saturation indices in waters sampled along their evaporative path are calculated by PHRQPITZ code to study their geochemical evolution. Saturation states calculated by the code have pointed out that al! brines sampled were saturated with respect to calcite, gypsum and anhydrite. However, their stability diagram shows that water activity values determine gypsum to be the more stable phase in the Ca-S04-H20 system for almost all samples. Halite, thenardite and bloedite reach saturation at a late stage during brine evolution. The evolving paths of mirabilite, glauberite, polyhalite and epsomite do not show any evidence of brine-mineral equilibrium process along evaporative evolution. Nevertheless, mirabilite saturation state should be taken with caution because of the lack of field temperature data. Calculations carried out at 15° C shows that mirabilite is affected by reequilibrium processes which take place at short temporal scales (daily fluctuations of temperature. The comparison of these results with those of Garcés et al. (1991, 1992 indicates that Pitzer' s formulation is the more adequate approach for the physicochemical treatment of highly concentrated waters. Theoretical simulation of evaporation process has been carried out using the most diluted sample like starting point. Open system in relation to gaseous exchange between brine and atmosphere, and constant temperature (25° C have been considered like boundary conditions along the calculations. Simulation results have faithfully reproduced the evolving path defined by means of physicochemical treatment of brine samples. This supports the previously posed hypothesis in relation to the sequence of mineral precipitation that should take place in the saline system. Moreover, this fact suggests

  18. Microplastic pollution in lakes and lake shoreline sediments - A case study on Lake Bolsena and Lake Chiusi (central Italy).

    Science.gov (United States)

    Fischer, Elke Kerstin; Paglialonga, Lisa; Czech, Elisa; Tamminga, Matthias

    2016-06-01

    Rivers and effluents have been identified as major pathways for microplastics of terrestrial sources. Moreover, lakes of different dimensions and even in remote locations contain microplastics in striking abundances. This study investigates concentrations of microplastic particles at two lakes in central Italy (Lake Bolsena, Lake Chiusi). A total number of six Manta Trawls have been carried out, two of them one day after heavy winds occurred on Lake Bolsena showing effects on particle distribution of fragments and fibers of varying size categories. Additionally, 36 sediment samples from lakeshores were analyzed for microplastic content. In the surface waters 2.68 to 3.36 particles/m(3) (Lake Chiusi) and 0.82 to 4.42 particles/m(3) (Lake Bolsena) were detected, respectively. Main differences between the lakes are attributed to lake characteristics such as surface and catchment area, depth and the presence of local wind patterns and tide range at Lake Bolsena. An event of heavy winds and moderate rainfall prior to one sampling led to an increase of concentrations at Lake Bolsena which is most probable related to lateral land-based and sewage effluent inputs. The abundances of microplastic particles in sediments vary from mean values of 112 (Lake Bolsena) to 234 particles/kg dry weight (Lake Chiusi). Lake Chiusi results reveal elevated fiber concentrations compared to those of Lake Bolsena what might be a result of higher organic content and a shift in grain size distribution towards the silt and clay fraction at the shallow and highly eutrophic Lake Chiusi. The distribution of particles along different beach levels revealed no significant differences.

  19. Diet overlap of top-level predators in recent sympatry: bull trout and nonnative lake trout

    Science.gov (United States)

    Guy, Christopher S.; McMahon, Thomas E.; Fredenberg, Wade A.; Smith, Clinton J.; Garfield, David W.; Cox, Benjamin S.

    2011-01-01

    The establishment of nonnative lake trout Salvelinus namaycush in lakes containing lacustrine–adfluvial bull trout Salvelinus confluentus often results in a precipitous decline in bull trout abundance. The exact mechanism for the decline is unknown, but one hypothesis is related to competitive exclusion for prey resources. We had the rare opportunity to study the diets of bull trout and nonnative lake trout in Swan Lake, Montana during a concomitant study. The presence of nonnative lake trout in Swan Lake is relatively recent and the population is experiencing rapid population growth. The objective of this study was to evaluate the diets of bull trout and lake trout during the early expansion of this nonnative predator. Diets were sampled from 142 bull trout and 327 lake trout during the autumn in 2007 and 2008. Bull trout and lake trout had similar diets, both consumed Mysis diluviana as the primary invertebrate, especially at juvenile stages, and kokanee Oncorhynchus nerka as the primary vertebrate prey, as adults. A diet shift from primarily M. diluviana to fish occurred at similar lengths for both species, 506 mm (476–545 mm, 95% CI) for bull trout and 495 mm (470–518 mm CI) for lake trout. These data indicate high diet overlap between these two morphologically similar top-level predators. Competitive exclusion may be a possible mechanism if the observed overlap remains similar at varying prey densities and availability.

  20. A Lake Dream in Asia

    Institute of Scientific and Technical Information of China (English)

    Yang Wei

    2009-01-01

    @@ When William Wordsworth,representative of Lake Poets wrote his Ode to Night ingale nearby the Lake District of England at the turn of the nine-teenth century,he never imagined a century later,a similar romantic lake dream has been created in China,Asia.

  1. Interesting Ziandao Lake

    Institute of Scientific and Technical Information of China (English)

    1998-01-01

    LOCATED in Chun’an County, Zhejiang Province, Qiandao Lake (Lake of a Thousand Isles) is a state-level scenic spot and a bright pearl of the golden tourism line between Hangzhou’s West Lake and Anhui’s Huangshan Mountain. Last autumn, we went to Chun’an. It took only three to four hours by coach to travel from Hangzhou to Chun’an. Flanked by mountains on the west, the small county faces water on the east. A street goes across the county; it takes less than half an hour to walk from one end to the other. Small restaurants and shops line the western side of the road,

  2. Viruses in Antarctic lakes

    Science.gov (United States)

    Kepner, R. L. Jr; Wharton, R. A. Jr; Suttle, C. A.; Wharton RA, J. r. (Principal Investigator)

    1998-01-01

    Water samples collected from four perennially ice-covered Antarctic lakes during the austral summer of 1996-1997 contained high densities of extracellular viruses. Many of these viruses were found to be morphologically similar to double-stranded DNA viruses that are known to infect algae and protozoa. These constitute the first observations of viruses in perennially ice-covered polar lakes. The abundance of planktonic viruses and data suggesting substantial production potential (relative to bacteria] secondary and photosynthetic primary production) indicate that viral lysis may be a major factor in the regulation of microbial populations in these extreme environments. Furthermore, we suggest that Antarctic lakes may be a reservoir of previously undescribed viruses that possess novel biological and biochemical characteristics.

  3. Network global navigation satellite system surveys to harmonize American and Canadian datum for the Lake Champlain Basin

    Science.gov (United States)

    Flynn, Robert H.; Rydlund, Jr., , Paul H.; Martin, Daniel J.

    2016-03-08

    Historically high flood levels were observed during flooding in Lake Champlain and the Richelieu River from late April through May 2011. Flooding was caused by record spring precipitation and snowmelt from the third highest cumulative snowfall year on record, which included a warm, saturated late spring snowpack. Flood stage was exceeded for a total of 67 days from April 13 to June 19, 2011. During this flooding, shoreline erosion and lake flood inundation were exacerbated by wind-driven waves associated with local fetch and lake-wide seiche effects. In May 2011, a new water-surface-elevation record was set for Lake Champlain. Peak lake-level water-surface elevations varied at the three U.S. Geological Survey lake-level gages on Lake Champlain in 2011. The May 2011 peak water-surface elevations for Lake Champlain ranged from 103.20 feet above the National Geodetic Vertical Datum of 1929 at the northern end of Lake Champlain (at its outlet into the Richelieu River at Rouses Point, New York) to 103.57 feet above the National Geodetic Vertical Datum of 1929 at the southern end of the Lake in Whitehall, New York. The water-surface elevations for the Richelieu River in Canada are referenced to a different vertical datum than are those in Lake Champlain in the United States, which causes difficulty in assessing real-time flood water-surface elevations and comparing of flood peaks in the Lake Champlain Basin in the United States and Canada.

  4. Factors of ecologic succession in oligotrophic fish communities of the Laurentian Great Lakes

    Science.gov (United States)

    Smith, Stanford H.

    1972-01-01

    species are greatly reduced or extinct in lakes Ontario and Erie, and are in various stages of decline in lakes Huron, Michigan, and Superior, from greatest to least, respectively. The percids appear to be near the end of their sequence of succession in lakes Erie, Ontario, and Huron (primarily Saginaw Bay) where only the yellow perch (Perca flavescens) remains abundant. The yellow perch appears to be on the brink of decline in Lake Erie, which has been more severely influenced by water quality change than the other lakes.

  5. Stages of Gastric Cancer

    Science.gov (United States)

    ... liver cancer . The following stages are used for gastric cancer: Stage 0 (Carcinoma in Situ) In stage 0 , abnormal cells are ... check-ups. Treatment Options by Stage Stage 0 (Carcinoma in ... Stage I Gastric Cancer Treatment of stage I gastric cancer may ...

  6. Lake Morphometry for NHD Lakes in Great Lakes Region 4 HUC

    Data.gov (United States)

    U.S. Environmental Protection Agency — Lake morphometry metrics are known to influence productivity in lakes and are important for building various types of ecological and environmental models of lentic...

  7. Algal wrack deposits and macroinfaunal arthropods on sandy beaches of the Chilean coast Depósitos de algas varadas y artrópodos macroinfaunales en playas de arena de la costa de Chile

    Directory of Open Access Journals (Sweden)

    EDUARDO JARAMILLO

    2006-09-01

    implications for sampling design of sandy beaches characterized by high inputs of algal wrack depositsSe muestrearon cuatro playas arenosas del litoral chileno durante el verano de 2000, para estudiar el rol de depósitos de algas varadas sobre las abundancias de las poblaciones de tres especies detritívoras de la macroinfauna que habita los niveles intermareales superiores de estas playas: el anfípodo talítrido Orchestoidea tuberculata Nicolet, el isópodo tílido Tylos spinulosus Dana y el insecto tenebriónido Phalerisidia maculata Kulzer. Las playas estudiadas fueron Apolillado (ca. 29º S, Quidico (ca. 38º S, Guabún y Mar Brava (ca. 42º S. Se recolectaron muestras replicadas con un cilindro plástico (25 cm de diámetro de los depósitos de algas, incluyendo el sedimento situado por debajo de los mismos y de zonas de la playa próximas a los acúmulos de algas pero carentes de las mismas. Las muestras se recolectaron en dos niveles de la playa, uno más próximo a la orilla con acúmulos de algas frescas y otro en la zona superior de la playa con algas secas. Los depósitos de algas varadas estuvieron compuestos principalmente por las algas pardas Macrocystis pyrifera (L., Durvillaea antarctica (Chamisso Hariot y Lessonia nigrescens Bory. O. tuberculata fue encontrada en los depósitos de algas y zonas de la playa cercanas a los mismos y estudiados en Apolillado, Quidico, Guabún y Mar Brava. Por otro lado, T. spinulosus fue recolectada solo en Apolillado, mientras que P. maculata ocurrió en los depósitos de algas y zonas de la playa cercanas a los mismos y analizados en Apolillado, Quidico y Guabún. En general, las abundancias medias de las tres especies fueron significativamente más altas en aquellas muestras recolectadas de los depósitos de algas y sedimentos subyacentes; i.e., 56, 61 y 14 veces más altas (promedios totales que en arenas sin restos de algas. Se concluye que las algas varadas sobre la superficie de la playa promueven un incremento de las

  8. Technologies for lake restoration

    Directory of Open Access Journals (Sweden)

    Helmut KLAPPER

    2003-09-01

    Full Text Available Lakes are suffering from different stress factors and need to be restored using different approaches. The eutrophication remains as the main water quality management problem for inland waters: both lakes and reservoirs. The way to curb the degradation is to stop the nutrient sources and to accelerate the restoration with help of in-lake technologies. Especially lakes with a long retention time need (eco- technological help to decrease the nutrient content in the free water. The microbial and other organic matter from sewage and other autochthonous biomasses, causes oxygen depletion, which has many adverse effects. In less developed countries big reservoirs function as sewage treatment plants. Natural aeration solves problems only partly and many pollutants tend to accumulate in the sediments. The acidification by acid rain and by pyrite oxidation has to be controlled by acid neutralizing technologies. Addition of alkaline chemicals is useful only for soft waters, and technologies for (microbial alkalinization of very acidic hardwater mining lakes are in development. The corrective measures differ from those in use for eutrophication control. The salinization and water shortage mostly occurs if more water is used than available. L. Aral, L. Tschad, the Dead Sea or L. Nasser belong to waters with most severe environmental problems on a global scale. Their hydrologic regime needs to be evaluated. The inflow of salt water at the bottom of some mining lakes adds to stability of stratification, and thus accumulation of hydrogen sulphide in the monimolimnion of the meromictic lakes. Destratification, which is the most used technology, is only restricted applicable because of the dangerous concentrations of the byproducts of biological degradation. The contamination of lakes with hazardous substances from industry and agriculture require different restoration technologies, including subhydric isolation and storage, addition of nutrients for better self

  9. Lakes on Mars

    CERN Document Server

    Cabrol, Nathalie A

    2014-01-01

    On Earth, lakes provide favorable environments for the development of life and its preservation as fossils. They are extremely sensitive to climate fluctuations and to conditions within their watersheds. As such, lakes are unique markers of the impact of environmental changes. Past and current missions have now demonstrated that water once flowed at the surface of Mars early in its history. Evidence of ancient ponding has been uncovered at scales ranging from a few kilometers to possibly that of the Arctic ocean. Whether life existed on Mars is still unknown; upcoming missions may find critic

  10. Use of Generalized Extreme Value Covariates to Improve Estimation of Trends and Return Frequencies for Lake Levels

    Science.gov (United States)

    Paynter, S.; Nachabe, M.

    2008-12-01

    One of the most important tools in water management is the accurate forecast of both long-term and short- term extreme values for both flood and drought conditions. Traditional methods of trend detection, such as ordinary least squares (OLS) or the Mann-Kendall test, are not aptly suited for hydrologic systems while traditional methods of predicting extreme flood and drought frequencies, such as distribution fitting without parameter covariates, may be highly inaccurate in lake-type systems, especially in the short-term. In the case of lakes, traditional frequency return estimates assume extremes are independent of trend or starting lake stages. However, due to the significant autocorrelation of lake levels, the initial stage can have a significant influence on the severity of a given event. The aim of this research was to accurately identify the direction and magnitude of trends in flood and drought stages and provide more accurate predictions of both long-term and short-term flood and drought stage return frequencies utilizing the generalized extreme value distribution with time and starting stage covariates. All of the lakes researched evidenced either no trend or very small trends unlikely to significantly alter prediction of future flood or drought return levels. However, for all of the lakes significant improvement in the prediction of extremes was obtained with the inclusion of starting lake stage as a covariate. Traditional methods of predicting flood or drought stages significantly overpredict stages when starting lake stages are low and underpredict stages when starting stages are high. The difference between these predictions can be nearly two meters, a significant amount in urbanized watersheds in areas of the world with flat topography. Differences of near two meters can mean significant alterations in evacuation or other water management decisions. In addition to improving prediction of extreme events, utilizing GEV with time or starting stage

  11. Reevaluation of lake trout and lake whitefish bioenergetics models

    Science.gov (United States)

    Madenjian, Charles P.; Pothoven, Steve A.; Kao, Yu-Chun

    2013-01-01

    Using a corrected algorithm for balancing the energy budget, we reevaluated the Wisconsin bioenergetics model for lake trout (Salvelinus namaycush) in the laboratory and for lake whitefish (Coregonus clupeaformis) in the laboratory and in the field. For lake trout, results showed that the bioenergetics model slightly overestimated food consumption by the lake trout when they were fed low and intermediate rations, whereas the model predicted food consumption by lake trout fed ad libitum without any detectable bias. The slight bias in model predictions for lake trout on restricted rations may have been an artifact of the feeding schedule for these fish, and we would therefore recommend application of the Wisconsin lake trout bioenergetics model to lake trout populations in the field without any revisions to the model. Use of the Wisconsin bioenergetics model for coregonids resulted in overestimation of food consumption by lake whitefish both in the laboratory and in the field by between 20 and 30%, on average. This overestimation of food consumption was most likely due to overestimation of respiration rate. We therefore adjusted the respiration component of the bioenergetics model to obtain a good fit to the observed consumption in our laboratory tanks. The adjusted model predicted the consumption in the laboratory and the field without any detectable bias. Until a detailed lake whitefish respiration study can be conducted, we recommend application of our adjusted version of the Wisconsin generalized coregonid bioenergetics model to lake whitefish populations in the field.

  12. Simulations of cataclysmic outburst floods from Pleistocene Glacial Lake Missoula

    Science.gov (United States)

    Denlinger, Roger P.; O'Connell, D. R. H.

    2009-01-01

    Using a flow domain that we constructed from 30 m digital-elevation model data of western United States and Canada and a two-dimensional numerical model for shallow-water flow over rugged terrain, we simulated outburst floods from Pleistocene Glacial Lake Missoula. We modeled a large, but not the largest, flood, using initial lake elevation at 1250 m instead of 1285 m. Rupture of the ice dam, centered on modern Lake Pend Oreille, catastrophically floods eastern Washington and rapidly fills the broad Pasco, Yakima, and Umatilla Basins. Maximum flood stage is reached in Pasco and Yakima Basins 38 h after the dam break, whereas maximum flood stage in Umatilla Basin occurs 17 h later. Drainage of these basins through narrow Columbia gorge takes an additional 445 h. For this modeled flood, peak discharges in eastern Washington range from 10 to 20 × 106 m3/s. However, constrictions in Columbia gorge limit peak discharges to 6 m3/s and greatly extend the duration of flooding. We compare these model results with field observations of scabland distribution and high-water indicators. Our model predictions of the locations of maximum scour (product of bed shear stress and average flow velocity) match the distribution of existing scablands. We compare model peak stages to high-water indicators from the Rathdrum-Spokane valley, Walulla Gap, and along Columbia gorge. Though peak stages from this less-than-maximal flood model attain or exceed peak-stage indicators along Rathdrum-Spokane valley and along Columbia gorge, simulated peak stages near Walulla Gap are 10–40 m below observed peak-stage indicators. Despite this discrepancy, our match to field observations in most of the region indicates that additional sources of water other than Glacial Lake Missoula are not required to explain the Missoula floods.

  13. Bioprospecting of Evaporative Lakes for Development of a Novel Paleo-aridity Metric

    Science.gov (United States)

    Finkelstein, D. B.; Snoeyenbos-West, O.; Pratt, L. M.

    2011-12-01

    Molecular genetic and biogeochemical analyses of recent microbial communities allows for targeting of specific organisms and their metabolites/biomarkers to use for paleoenvironmental reconstruction of early Earth. Of these, the distribution of wax esters (WE) in evaporative microbial mats suggests that they are the favored biosynthetic products during periods of desiccation. Biosynthesis and storage of long-chain, low-solubility WE resistant to degradation may have evolved to enhance survival and migration of microbial communities in desiccation prone settings such as ephemeral lakes. Such a strategy would have aided colonization of extreme, early terrestrial environments. Molecular analyses using 16SrRNA gene sequencing of clone libraries from alkaline ephemeral lake and hot spring microbial mats in the Warner Valley, Oregon, indicate a predominance (78%) of desiccation-tolerant and endospore forming microorganisms that are able to produce and store WE as well as other "xeroprotectants" i.e., compatible solutes that enable the long-term stability of biomolecules in the dry state (Narvaez-Reinaldo et al., 2010). Water chemistries range from moderately to highly alkaline to sulfate-chloride dominated, ranging widely in pH (8.3-10.5) and total dissolved solids (25-300,000 ppm). Throughout the system, microbial mats in the lakes, playas, and springs are controlled by temperature and chemistry, augmented by seasonally dynamic microbial populations that respond to profound shifts in temperature, pH and ion and metal concentrations. For example, arsenic in some of the lakes ranges from 600-10,000 ppb (pH = 8.6-9.4), weathering from localized occurrences arsenic mineralization in the watershed, and hosts purple-sulfur bacteria and favors vertically structured microbial mat communities tolerant of rapid changes in surface aridity and water chemistry. Emergent, dry mats in these lakes are dominated by members of the bacterial phyla Firmicutes (75%) and Bacteriodetes (23

  14. Paleoclimatic Change Inferred from Carbon Isotope Composition of Organic Matter in Sediments of Dabusu Lake, Jilin Province, China

    Institute of Scientific and Technical Information of China (English)

    SHEN Ji(沈吉); ZHANG Enlou(张恩楼); YANG Xiangdong(羊向东); Ryo Matsumoto

    2004-01-01

    Study on the organic compounds and stable isotope composition of a sediment section in Dabusu Lake revealed that the organic materials in the sediments came mainly from terrestrial plants brought into the lake by runoff. The δ13C of the organic materials had high values during warm-dry climatic stages and decreased in cold-wet stages. Analysis of data on carbonate content and 14 C age showed that the lake basin had experienced several wet-cold and warm-dry climatic cycles since 15000 a BP. Since 6700 a BP, the climate reached a relatively stable warm-dry stage, so that the lake water was gradually condensed and finally a saline lake was formed.

  15. Lake whitefish diet, condition, and energy density in Lake Champlain and the lower four Great Lakes following dreissenid invasions

    Science.gov (United States)

    Herbst, Seth J.; Marsden, J. Ellen; Lantry, Brian F.

    2013-01-01

    Lake Whitefish Coregonus clupeaformis support some of the most valuable commercial freshwater fisheries in North America. Recent growth and condition decreases in Lake Whitefish populations in the Great Lakes have been attributed to the invasion of the dreissenid mussels, zebra mussels Dreissena polymorpha and quagga mussels D. bugensis, and the subsequent collapse of the amphipod, Diporeia, a once-abundant high energy prey source. Since 1993, Lake Champlain has also experienced the invasion and proliferation of zebra mussels, but in contrast to the Great Lakes, Diporeia were not historically abundant. We compared the diet, condition, and energy density of Lake Whitefish from Lake Champlain after the dreissenid mussel invasion to values for those of Lake Whitefish from Lakes Michigan, Huron, Erie, and Ontario. Lake Whitefish were collected using gill nets and bottom trawls, and their diets were quantified seasonally. Condition was estimated using Fulton's condition factor (K) and by determining energy density. In contrast to Lake Whitefish from some of the Great Lakes, those from Lake Champlain Lake Whitefish did not show a dietary shift towards dreissenid mussels, but instead fed primarily on fish eggs in spring, Mysis diluviana in summer, and gastropods and sphaeriids in fall and winter. Along with these dietary differences, the condition and energy density of Lake Whitefish from Lake Champlain were high compared with those of Lake Whitefish from Lakes Michigan, Huron, and Ontario after the dreissenid invasion, and were similar to Lake Whitefish from Lake Erie; fish from Lakes Michigan, Huron, and Ontario consumed dreissenids, whereas fish from Lake Erie did not. Our comparisons of Lake Whitefish populations in Lake Champlain to those in the Great Lakes indicate that diet and condition of Lake Champlain Lake Whitefish were not negatively affected by the dreissenid mussel invasion.

  16. Estructura de las comunidades de peces de arrecife en las Islas Catalinas y Playa Ocotal, Pacífico Norte de Costa Rica

    Directory of Open Access Journals (Sweden)

    Mario Espinoza

    2005-09-01

    Full Text Available Los arrecifes son sistemas muy complejos, cuya heterogeneidad mantiene una gran diversidad de organismos. La estructura de las comunidades de peces que forman parte del arrecife varía dentro y entre arrecifes, y se esperaría que la heterogeneidad y estructura del arrecife vaya a influir en la estructura de las comunidades de peces que habitan. Se estudiaron cuatro arrecifes en las Islas Catalinas (Sur, La Pared, Roca Sucia y Sombrero y uno en la Playa de Ocotal, Pacífico Norte de Costa Rica. Se encontraron diferencias claras en la estructura y composición de las comunidades de peces de arrecife en las Islas Catalinas y Playa Ocotal, y la estructura y composición del hábitat explicaron la mayor parte de la varianza. Ciertos atributos del arrecife como la presencia del alga Caulerpa sertularoides en Ocotal, así como los corales Tubastrea coccinea y Pocillopora spp., en las Islas Catalinas explicaron la variabilidad que existía entre los sitios y como afectaba a la estructura de la comunidad de peces de arrecife. La mariposa Johnrandalia nigrirostris, la damisela Microspathodon dorsalis y el cirujano Prionurus punctatus se correlacionaron directamente con el coral ahermatípico Tubastrea coccinea, en el arrecife de Roca Sucia, mientras que Holocanthus passer se asocio a arrecifes con un mayor porcentaje de sustrato rocoso. Otras especies como Abudefduf troschelli y Halichoeres dispilus se encontraban en mayor cantidad en el arrecife de Ocotal, en donde dominaba el alga Caulerpa sertularioides. Por último, el número y abundancia de peces de arrecife se correlacionó directamente con el índice de rugosidad del sustrato en los arrecifes de Roca Sucia y Ocotal, pero no así los de la Pared y Sombrero.Structure of reef fish communities in Catalinas Islands and Ocotal beach, North Pacific of Costa Rica. The reefs are heterogeneous systems that maintain a high diversity of organisms. Fish community structure varies within and among reefs, so it

  17. Futuro del turismo de masas sol y playa del litoral mediterráneo español / Future mass tourism of sun and beach Spanish Mediterranean littoral

    Directory of Open Access Journals (Sweden)

    Marta Collado Lara

    2013-01-01

    Full Text Available ResumenLa situación problemática de los destinos maduros de demanda masiva sol y playa del litoral español y las medidas encaminadas, por las políticas turísticas, a la mejora de la pérdida de competitividad del sector, requieren un nuevo modelo de desarrollo turístico para estos destinos. El objetivo del trabajo, es aportar valor añadido al diseño de nuevos modelos de desarrollo turístico de futuro mediante la aplicación de las herramientas de prospectiva territorial, como instrumento capaz de reforzar procesos de planificación. Para mostrar la viabilidad de estas herramientas se lleva a cabo una valoración de similitudes o brechas entre dos modelos de desarrollo turístico; por un lado, un modelo de desarrollo hipotético de un destino maduro del litoral mediterráneo [utilizando las herramientas de prospectiva territorial] y, por otro, el modelo de desarrollo de un Proyecto Piloto de un caso real de planeamiento urbanístico. Los resultados de la valoración revelan que los dos modelos presentan muchas similitudes, lo que permite mostrar el potencial de la prospectiva territorial como instrumento para hacer frente a los problemas de desarrollo turístico plagados de complejidad e incertidumbre, así como su capacidad para reducir el análisis de los desafíos globales a las implicaciones locales y espaciales.Palabras claveDestinos maduros, prospectiva, demanda masiva sol y playa, incertidumbre, desarrollo turísticoAbstractThe problematic situation of the mature destinations of massive demand of sun and beach of the Spanish littoral and the measures directed to the improvement of the loss of competitiveness of the sector, demand a new model of tourist development for these destinations. The aim of the work is to supply added value to the design of new models of future tourist development by means of the application of the territorial foresight tools, as a tool able to reinforce planning processes. To demonstrate the viability of

  18. Paleosandstorm characteristics and lake evolution history deduced from investigation on lacustrine sediments--The case of Hongjiannao Lake, Shaanxi Province

    Institute of Scientific and Technical Information of China (English)

    SHEN Ji; WANG Yong; YANG Xiangdong; ZHANG Enlou; YANG Bao; JI Junfeng

    2005-01-01

    Sediment cores from desert lakes serve as good records of the frequency and intensity of sandstorms in history. By multi-proxy analysis of grain-size, magnetic susceptibility, TOC and Rb/Sr ratio, the paleosandstorm characteristics and lake evolution history in Yulin Area for the past 80 years. are discussed in this article. It is revealed that Hongjiannao Lake formed in about 1928 A.D. and in its initial stage sandstorms were prevalent with three extremes taking place in 1936 A.D., 1939 A.D. and 1941 A.D.. During the expansion period of 1952―1960 A.D., inflow waters to the lake increased sharply and a lot more weathered materials were carried into the lake. The frequency and intensity of sandstorms have reduced a lot since 1960s and the "double peaks" feature of the grain-size frequency curve has changed into the "single peak" feature. Study on the catchment ecology of the lake shows that the occurrence of sandstorms has been effectively restrained by the forest plantation and water and soil conservation.

  19. Reassessment of the Genesis of "Thaw Lakes" on the Arctic Coastal Plain in Northern Alaska

    Science.gov (United States)

    Shur, Y.; Jorgenson, M. T.

    2004-12-01

    Oriented lakes and drained lake basins on the Arctic Coastal Plain in northern Alaska have been the subject of numerous studies for more than 50 years. From the beginning, the waterbodies have been described as "thaw lakes" and since then a thermokarst genesis for the lakes has been accepted without any quantitative analysis of the initial permafrost conditions and thaw-susceptibility of the upper permafrost. We initially sought to quantify ground ice changes in support of this concept through detailed permafrost and terrain studies in the northeastern NPRA, an area with thick deposits of loamy sand and abundant lakes. During 2001-2004 we conducted detailed terrain analyses that included field surveys, permafrost investigations, and photogrammetry. A terrain-unit approach was used to relate soil and ground ice properties to surficial deposits related to lake development. Cryogenic structures, ice volumes, and properties of upper permafrost were described from borehole cores taken from every stage of lake-basin development and in surrounding areas. Ground ice also was described and sampled at 20 exposures at lake and riverbanks. We classified stages of drained basin development and quantified their permafrost characteristics. The primary stage of lake development is usually described as degradation of ice-wedges at their intersections. A thaw bulb then develops under the deep water and the thaw lakes expand laterally through both mechanical and thermal erosion. Although we observed numerous ponds at ice-wedge crossings we did not observe later sequential stages of thaw lake development. Instead, we observed that initial shallow ponds were soon colonized by vegetation, which halted thermokarst. In addition, ice volumes and thaw settlement properties of soils were insufficient to allow thaw lake development. Under the standard concept of lake development, the formation of ice wedges raises the surface and allows the development of new thermokarst, and thus creates a

  20. Poet Lake Crystal Approval

    Science.gov (United States)

    This September 19, 2016 letter from EPA approves the petition from Poet Biorefining-Lake Crystal, regarding non-grandfathered ethanol produced through a dry mill process, qualifying under the Clean Air Act for renewable fuel (D-code 6) RINs under the RFS

  1. in lake chamo, ethiopia

    African Journals Online (AJOL)

    ADMIN

    zooplankton until they move to the littoral regions and start feeding .... Fish collected during the spawning season (i.e.,. March-June .... females, but sampling in the estuary downstream ... same size could be first-time spawners in Lake. Chamo ...

  2. Reclaiming the lake

    DEFF Research Database (Denmark)

    Rasmussen, Mattias Borg

    2016-01-01

    of individual rights that move well beyond the site of conflict. It is therefore argued that the actions to reclaim Lake Conococha were not only a battle for natural resources and clean water, but more fundamentally an attempt to repossess a citizenship that may be constitutionally secured but all too oft en...

  3. Lake Ontario: Nearshore Variability

    Science.gov (United States)

    We conducted a high-resolution survey with towed electronic instrumentation along the Lake Ontario nearshore (720 km) at a 20 meter contour. The survey was conducted September 6-10, 2008 with a shorter 300 km survey conducted August 14-15 for comparing of temporal variability. ...

  4. Pesquería y biología de Rhinobatos percellens (Rajiformes: Rhinobatidae capturados por la pesquería artesanal de playa La Pared, Venezuela

    Directory of Open Access Journals (Sweden)

    Alejandro Tagliafico

    2013-03-01

    Full Text Available Rhinobatos percellens es capturada en Venezuela por la flota artesanal que opera con redes de fondo. Está clasificada por la IUCN como casi amenazada, y no existen estudios sobre su biología o pesquería en el país. Por ello, se analizaron desembarques de la pesca artesanal de playa la Pared (isla de Margarita durante enero-diciembre 2007. A cada ejemplar capturado se le determinó la longitud total, sexo y madurez. Fueron analizados 210 ejemplares, 159 hembras y 51 machos. El 81% de los ejemplares se encontraban maduros y un 27% de este grupo correspondió a hembras grávidas. La talla media de madurez sexual quedó ubicada en 51 y 52cm para hembras y machos, respectivamente. Se detectaron hembras maduras todo el año, y hembras grávidas en siete meses. Fueron analizados 96 embriones con tallas entre 2-19cm, siendo la fecundidad máxima cuatro embriones. La variación de las longitudes de los embriones entre los meses del año indican dos picos máximos de alumbramiento al año pero no existe una sincronía en la cópula ya que la especie se reproduce prácticamente todo el año. Se recomienda elaborar regulaciones pesqueras que incluyan una talla mínima de captura en función de la talla de madurez señalada y liberar las hembras grávidas al agua.

  5. CONCENTRACIÓN DE MINERALES DE TITANIO CONTENIDOS EN LAS ARENAS DE PLAYAS DE LA REGIÓN DE ATACAMA - CHILE

    Directory of Open Access Journals (Sweden)

    Luis Valderrama Campusano

    2008-07-01

    Full Text Available El presente trabajo tiene como fin caracterizar y concentrar minerales de titanio contenidos en las arenas de playas de la Región de Atacama. El análisis mineralógico indicó que los principales constituyentes son cuarzo, feldespato, ilmenita, titanita, rutilo y trazas de circonita, monacita y wolframita. Los análisis químicos indican que la ley de TiO2 es de 2,3% y 3,15% para las arenas de Huasco y Caldera, respectivamente. Al retirar el material sobre 0,300 mm, se produce una preconcentración, aumentando las leyes de TiO2 a 5,33% para Huasco y 6,48% para Caldera. Las pruebas de concentración gravitacional fueron realizadas en una mesa Wilfley, y fueron estudiados diferentes ángulos de inclinación de la mesa, para la concentración primaria (2,5°; 3,0°; 3,5º y 4,0° y la limpieza (5,0°; 5,5; 6,0° y 6,5° respectivamente. Los mejores resultados fueron obtenidos usando un ángulo de inclinación de 3,0° para la concentración primaria y 6,0° para limpiar el concentrado. Con estos resultados se diseñó un circuito para las arenas de Huasco, lográndose un concentrado final con una ley de 46,0% de TiO2 y una recuperación de 21,2%, y para Caldera, se obtuvo un concentrado final de 51,3% TiO2 con una recuperación de 17,4%.

  6. [Reproductive pattern and mean size of sexual maturity of female lobsters Panulirus gracilis (Decapoda: Palinuridae) in Playa Lagarto, Guanacaste, Costa Rica].

    Science.gov (United States)

    Naranjo Madrigal, Helven

    2012-12-01

    The lobster P. gracilis is important as a fishery resource and also contributes to food security of fishers in coastal communities in the North Pacific of Costa Rica. Due to the importance of updating knowledge related to the reproductive pattern of this species, we analyzed 357 specimens of female lobsters caught by the fishing methods of "hookah" and lung diving, from November 2007 to October 2008 in Playa Lagarto. Furthermore, we examined the size composition by depth; monthly pattern of reproductive activity (RAI) associated with the relative increase in sea surface temperature, and also the mean size at maturity using Generalized Linear Models. Four physiological states of sexual maturity showed that females with no signs of mating or sexual maturity have a minimum mean size of 62.3mm of cephalothorax length (CL). There are characteristics of functional maturity from very small sizes ranging from 30 to 50mm CL, being the smallest berried female reported for this specie of 35.8mm CL and the highest percentage of mature females between 70 and 80mm CL. Percentages of RAI remained above 50% during the year except October and January. In addition, it observed an increase in the RAI that started from April and continued until August associated with a relative increase in temperature on March, although the correlation was not significant (r2=0.49, p>0.05). It is possible that the low mean size at maturity (70.2mm LC) for P. gracilis in this region is related to the fishing activity. It recommends the establishment of a ban in the region of at least five months (April-August) in order to protect the reproductive seasonality of the species and to promote a recruitment increase in the fishing areas.

  7. Hydrologic data and description of a hydrologic monitoring plan for Medicine Lake Volcano, California

    Science.gov (United States)

    Schneider, Tiffany Rae; McFarland, W.D.

    1996-01-01

    A hydrologic reconnaissance of the Medicine Lake Volcano area was done to collect data needed for the design of a hydrologic monitoring plan. The reconnaissance was completed during two field trips made in June and September 1992, during which geothermal and hydrologic features of public interest in the Medicine Lake area were identified. Selected wells, springs, and geothermal features were located and documented, and initial water-level, discharge, temperature, and specific-conductance measurements were made. Lakes in the study area also were surveyed during the September field trip. Temperature, specific- conductance, dissolved oxygen, and pH data were collected by using a multiparameter probe. The proposed monitoring plan includes measurement of water levels in wells, discharge from springs, and lake stage, as well as analysis of well-,spring-, and lake-water quality. In determining lake-water quality, data for both stratified and unstratified conditions would be considered. (Data for stratified conditions were collected during the reconnaissance phase of this project, but data for unstratified conditions were not.) In addition, lake stage also would be monitored. A geothermal feature near Medicine Lake is a "hot spot" from which hot gases discharge from two distinct vents. Gas chemistry and temperature would be monitored in one of these vents.

  8. Use of electricity to sedate Lake Trout for intracoelomic implantation of electronic transmitters

    Science.gov (United States)

    Faust, Matthew D.; Vandergoot, Christopher; Hostnik, Eric T.; Binder, Thomas R.; Mida Hinderer, Julia L.; Ives, Jessica T.; Krueger, Charles Conrad

    2017-01-01

    Use of telemetry data to inform fisheries conservation and management is becoming increasingly common; as such, fish typically must be sedated before surgical implantation of transmitters into the coelom. Given that no widely available, immediate-release chemical sedative currently exists in North America, we investigated the feasibility of using electricity to sedate Lake Trout Salvelinus namaycush long enough for an experienced surgeon to implant an electronic transmitter (i.e., 180 s). Specifically, our study objectives were to determine (1) whether some combination of electrical waveform characteristics (i.e., duty cycle, frequency, voltage, and pulse type) could sedate Lake Trout for at least 180 s; and (2) whether Lake Trout that were sequentially exposed to continuous DC and pulsed DC had greater rates of spinal injury and short-term mortality than control fish. A Portable Electrosedation System unit was used to sedate hatchery and wild Lake Trout. Dual-frequency pulsed-DC and two-stage approaches successfully sedated Lake Trout and had similar induction and recovery times. Lake Trout sedated using the two-stage approach did not have survival rates or spinal abnormalities that were significantly different from those of control fish. We concluded that electricity was a viable alternative to chemical sedatives for sedating Lake Trout before surgical implantation of an electronic transmitter, but we suggest that Lake Trout and other closely related species (e.g., Arctic Char Salvelinus alpinus) may require morphotype-specific electrical waveforms due to their morphological diversity.

  9. Rehabilitación de edificios bajo objetivos de reducción de impacto ambiental: un caso piloto de vivienda plurifamiliar en el área de Playa de Palma, Mallorca

    Directory of Open Access Journals (Sweden)

    Wadel, G.

    2011-10-01

    Full Text Available This article presents briefly the work Pilot study to reduce environmental impact: evaluation and assessment of a sustainable refurbishment of an existing residential building in Playa de Palma carried out by the Consortium of Palma Beach. It will be explained by how the environmental impacts of the building can be reduced by 50% or more as a result of future refurbishment and subsequent management, referring to both its current situation and refurbishment standards in residential buildings. It also includes an approximated evaluation of the CO2 emission reduction achieved in the building life cycle and the projected costs for the various actions of the refurbishment model proposed by the Consortium, to be carried out in other renovation operations in Palma Beach.

    Este artículo resume el estudio Experiencia piloto para la reducción del impacto ambiental: evaluación y asesoramiento a la rehabilitación sostenible de un edificio de viviendas existente en Playa de Palma realizado para el Consorci de Platja de Palma. Se explica a través de qué medidas es posible reducir en un 50% o más los impactos ambientales del edificio como producto de su futura rehabilitación y posterior gestión respecto tanto de su situación actual como de los estándares de rehabilitación al uso en edificios de vivienda. Asimismo, se incluye también una aproximación a las reducciones de emisiones de CO2 que se consiguen en el ciclo de vida del edificio y a los costes previstos para las distintas actuaciones del modelo de rehabilitación que el citado consorcio propone para las operaciones de rehabilitación a llevarse adelante en Playa de Palma.

  10. Microbiology of Lonar Lake and other soda lakes.

    Science.gov (United States)

    Antony, Chakkiath Paul; Kumaresan, Deepak; Hunger, Sindy; Drake, Harold L; Murrell, J Colin; Shouche, Yogesh S

    2013-03-01

    Soda lakes are saline and alkaline ecosystems that are believed to have existed throughout the geological record of Earth. They are widely distributed across the globe, but are highly abundant in terrestrial biomes such as deserts and steppes and in geologically interesting regions such as the East African Rift valley. The unusual geochemistry of these lakes supports the growth of an impressive array of microorganisms that are of ecological and economic importance. Haloalkaliphilic Bacteria and Archaea belonging to all major trophic groups have been described from many soda lakes, including lakes with exceptionally high levels of heavy metals. Lonar Lake is a soda lake that is centered at an unusual meteorite impact structure in the Deccan basalts in India and its key physicochemical and microbiological characteristics are highlighted in this article. The occurrence of diverse functional groups of microbes, such as methanogens, methanotrophs, phototrophs, denitrifiers, sulfur oxidizers, sulfate reducers and syntrophs in soda lakes, suggests that these habitats harbor complex microbial food webs that (a) interconnect various biological cycles via redox coupling and (b) impact on the production and consumption of greenhouse gases. Soda lake microorganisms harbor several biotechnologically relevant enzymes and biomolecules (for example, cellulases, amylases, ectoine) and there is the need to augment bioprospecting efforts in soda lake environments with new integrated approaches. Importantly, some saline and alkaline lake ecosystems around the world need to be protected from anthropogenic pressures that threaten their long-term existence.

  11. Lake trout rehabilitation in Lake Erie: a case history

    Science.gov (United States)

    Cornelius, Floyd C.; Muth, Kenneth M.; Kenyon, Roger

    1995-01-01

    Native lake trout (Salvelinus namaycush) once thrived in the deep waters of eastern Lake Erie. The impact of nearly 70 years of unregulated exploitation and over 100 years of progressively severe cultural eutrophication resulted in the elimination of lake trout stocks by 1950. Early attempts to restore lake trout by stocking were unsuccessful in establishing a self-sustaining population. In the early 1980s, New York's Department of Environmental Conservation, Pennsylvania's Fish and Boat Commission, and the U.S. Fish and Wildlife Service entered into a cooperative program to rehabilitate lake trout in the eastern basin of Lake Erie. After 11 years of stocking selected strains of lake trout in U.S. waters, followed by effective sea lamprey control, lake trout appear to be successfully recolonizing their native habitat. Adult stocks have built up significantly and are expanding their range in the lake. Preliminary investigations suggest that lake trout reproductive habitat is still adequate for natural reproduction, but natural recruitment has not been documented. Future assessments will be directed toward evaluation of spawning success and tracking age-class cohorts as they move through the fishery.

  12. Estudio y clasificación de la materia orgánica dispersa (MOD en el Lías de la Playa de Peñarrubia (Asturias

    Directory of Open Access Journals (Sweden)

    González Prado, J. J.

    1990-04-01

    Full Text Available A study of the organic matter of a marine sequence of the west part from Peñarrubia Beach (Asturias has been carried out using pyrolysis tests and petrographic and geochemical techniques. White light and fluorescence microscopic observations have permitted to establish a general classification of the disperse organic matter, its distribution and concentration along the series, and also the variation with the litology. The organic components have been classified into nine groups which are mainly found in the Upper part of the Pliensbachian marlaceous and lutitic beds. These bituminous leveis are composed of a kerogen type 11 or mixed, with a small contribution of terrestrial humic materials. The rank of DOM has been determined by huminite reflectance and Rock-Eval (Tmax, being both results concordant. The DOM is in an inmature stage before the oil generation window. The highest oil yields determined by pyrolysis tests at 500°C correspond to the richest DOM levels. Petrographic and geochemical data show a good correlation. AIgae, fibers, organic-mineral matrix and other submicroscopic associations are the main source for oil generation.En el presente trabajo se estudia por técnicas petrográficas y mediante ensayos de pirólisis o técnicas geoquímicas la serie marina del borde Oeste de la Playa de Peñarrubia (Asturias para conocer la naturaleza de su parte orgánica. Las observaciones microscópicas en luz blanca y por fluorescencia han permitido establecer una clasificación general de la materia orgánica dispersa, su distribución y concentración a lo largo de toda la serie y según las diferentes litologías. Se han clasificado los componentes orgánicos en 9 grupos mayoritarios que se concentran, principalmente en los niveles margosos y lutíticos del Pliensbachiense, habiéndose delimitado niveles bituminosos en la parte superior de la serie. Estos están constituidos por un kerógeno de tipo 11 mixto formado por un material aut

  13. Estudio y análisis de parámetros de eficiencia energética en viviendas. Caso práctico apartamento en Playa Puebla de Farnals de Valencia.

    OpenAIRE

    TORRES PEREZ, ALEJANDRO

    2015-01-01

    [ES] El presente TFG pretende evaluar las condiciones de una vivienda situada en la localidad de La Pobla de Farnals, en la provincia de Valencia. La vivienda objeto de estudio data del año 1976. Se trata de un apartamento usado como segunda residencia ubicado en una zona de playa. En él se han estudiado y evaluado las condiciones naturales de soleamiento y vientos a las que está expuesta la vivienda, así como las condiciones de consumo y el gasto energético. La conclusión es que dicho aparta...

  14. Sandy beach macroinfauna from the coast of Ancud, Isla de Chiloé, southern Chile Macroinfauna de playas arenosas en la costa de Ancud, Isla de Chiloé, sur de Chile

    Directory of Open Access Journals (Sweden)

    EDUARDO JARAMILLO

    2000-12-01

    compactness. Taxonomic composition, community structure and across shore zonation of that macroinfauna were similar to that from beaches located further north of Canal de ChacaoSe muestrearon seis playas arenosas en la costa de Ancud, Isla de Chiloé, sur de Chile (ca. 42º S con los siguientes propósitos: 1 estudiar la estructura comunitaria y la zonación transversal de la macroinfauna intermareal en relación a tipos de playas, y 2 analizar cuan similares o diferentes en composición taxonómica y estructura comunitaria son esas macroinfaunas con aquellas que habitan playas arenosas localizadas al norte del Canal de Chacao, el límite entre la Isla de Chiloé y el continente. Se recolectaron muestras de sedimento (0.1 m², 30 cm de profundidad (abril-mayo 1998 con cilindros plásticos en quince niveles igualmente espaciados entre sí y ordenados a lo largo de tres transectos replicados (separados por 1 m y extendidos entre un nivel ubicado por sobre el nivel de la marea alta y la zona de resaca. El sedimento se filtró en mallas de 1 mm de abertura y el residuo se fijó en formalina al 5% hasta posterior sorteo en el laboratorio. Para definir tipos de playas, se calculó el parámetro de Dean en base a mediciones de altura y periodo de la ola y velocidad de sedimentación de las partículas de la zona de resaca. Esos cálculos muestran que una de las playas es disipativa, mientras que las otras cinco tienen características de playas reflectivas o intermedias bajas. Los valores más altos de riqueza de especies y abundancia de la macroinfauna total ocurrieron en la playa disipativa (11 especies y 59705 ind m-1, respectivamente, los más bajos en el sitio más reflectivo (3 especies y 507 ind m-1, respectivamente. En general, las abundancias de organismos fueron más altas que las predichas por un modelo mundial de estructura comunitaria de playas arenosas. El anfípodo talítrido Orchestoidea tuberculata, el isópodo cirolánido Excirolana hirsuticauda y el dec

  15. Caracterización química de los sedimentos sumergidos, elemento clave dentro de un programa de monitoreo ambiental integral en las playas de la Bahía de Matanzas

    OpenAIRE

    Almeida Rodríguez, M.; de Armas Vargas, Y.; Rojas López., L.

    2010-01-01

    La bahía de Matanzas es un ecosistema complejo que posee como uno de sus principales problemas el vertido de residuales líquidos de origen industrial y urbano. La deposición de vertidos puede producir una contaminación permanente de los fondos de la bahía que inducen alteraciones en las cadenas tróficas afectando a plantas y animales. Las playas ubicadas dentro de la bahía se encuentran influenciadas por el aporte directo y continuo de contaminantes de origen orgánico e inorgánico...

  16. Contaminación de las playas por vertido de hidrocarburos procedentes de buques: las actuaciones de la demarcación de costas en la bahía de Algeciras (Cádiz, España)

    OpenAIRE

    Carmona, Alberto; Muñoz-Perez, Juan J.; Gomez-Pina, Gregorio; Piniella Corbacho, Francisco

    2009-01-01

    En todas aquellas situaciones accidentales en las que se pueda generar contaminación de las playas por vertidos de hidrocarburos resulta necesario disponer la aplicación de un Plan de Emergencia que posibilite una respuesta integral y coordinada. Tanto por la complejidad de las operaciones a desarrollar, como por la importancia del factor tiempo en las medidas a adoptar, es preciso asegurar una respuesta organizada que integre tanto los medios de la Comunidad Autónoma de Andalucía como aquell...

  17. Beneficios del Programa Bandera Azul Ecológica para las playas de excelencia en los aspectos higiénicos sanitarios: Costa Rica, períodos 1996 - 1997

    OpenAIRE

    Darner Mora Alvarado

    1997-01-01

    En el presente trabajo se resumen los objetivos general y específicos, metodología, resultados y beneficios obtenidos en 1996 y 1997 con la implementación del Programa Bandera Azul Ecológica, cuyo objetivo fundamental es promover el desarrollo de las zonas costeras en concordancia con la protección ambiental del mar, y más específicamente las hermosas playas de Costa Rica. Los resultados obtenidos en sus dos primeros años de ejecución demuestran grandes beneficios para las comunidades costera...

  18. Evaluación de amenazas antropogénicas en ecosistemas de playa en San Andrés, una isla pequeña del Caribe Suroccidental

    OpenAIRE

    Guerra Vargas1, Luis A.; Mancera Pineda, José Ernesto

    2015-01-01

    Evaluaciones de amenazas antropogénicas a los servicios ecosistémicos marinos, a partir del enfoque de percepción del riesgo, son muy escasas en las islas del Gran Caribe. En el presente trabajo se presenta la valoración de las amenazas derivadas del uso del ecosistema de playas de San Andrés, una isla pequeña del Caribe. Para evaluar las amenazas por uso se adelantaron encuestas y a partir de métodos de cartografía social, se obtuvieron mapas de niveles de percepción, con magnitudes relat...

  19. Diversidad, estructura y variación temporal del ensamble de peces asociados al arrecife coralino de Playa Mora, Bahía de Tenacatita, México Diversity, structure, and temporal variation of fish assemblages associated to Playa Mora coral reef, Tenacatita Bay, Mexico

    Directory of Open Access Journals (Sweden)

    Cristian Moisés Galván-Villa

    2011-08-01

    Full Text Available En este estudio se describe la estructura y variación temporal del ensamble de peces asociados al arrecife coralino de Playa Mora, Jalisco, México. El registro de especies se realizó mediante censos visuales en banda de 50 × 5 m, en tres diferentes épocas del año (templado-seca, cálido-húmeda y cálido-seca. Se registró un total de 5,689 peces de 64 especies. Las familias mejor representadas por su riqueza de especies fueron Labridae (7 y Pomacentridae (6. Mediante el índice de valor biológico se determinó que las especies dominantes fueron Thalassoma lucasanum, Stegastes acapulcoensis, Microspathodon dorsalis y Prionurus punctatus. Los ensambles de peces por riqueza específica y grupos tróficos presentaron cambios temporales. La época templado-seca presentó la mayor riqueza y abundancia de peces. La composición por categorías tróficas estuvo representada principalmente por peces carnívoros, los cuales fueron dominantes en el arrecife. Las especies carnívoras, carnívoras coralívoras, coralívoras obligadas, herbívoras, zooplanctívoras y parasíticas estuvieron mejor representadas en la época templada, mientras que las omnívoras aumentaron en la cálida.This study describes the structure and temporal variation of fish assemblages associated with Playa Mora coral reef, Jalisco, México. The species present were recorded with visual censuses along transects of 50 × 5 m, in three different seasons of the year (temperate-dry, warm-rainy, and warm-dry. A total of 5,689 fishes of 64 species were recorded. The best represented families according to species richness were Labridae (7 and Pomacentride (6. The biological value index determined that Thalassoma lucasanum, Stegastes acapulcoensis, Microspathodon dorsalis, and Prionu-rus punctatus were the dominant species. The fish assemblages by specific richness and trophic groups displayed temporal changes. The temperate-dry season presented the greatest richness and abundance of

  20. Evolution of alkaline lakes - Lake Van case study

    Science.gov (United States)

    Tillman Meyer, Felix; Viehberg, Finn; Bahroun, Sonya; Wolf, Annabel; Immenhauser, Adrian; Kwiecien, Ola

    2017-04-01

    Lake Van in Eastern Anatolia (Turkey) is the largest terminal soda lake on Earth. The lake sedimentary profile covers ca. 600 ka (Stockhecke et al. 2014) Based on lithological changes, the presence of freshwater microfossils and close-to-freshwater pH value in the pore water, members of ICDP PALEOVAN concluded that Lake Van might have started as an open lake. Here we show paleontological and geochemical evidence in favour of this idea and constrain the time, when Lake Van likely transformed into a closed lake. Additionally we provide the first conceptual model of how this closure may have happened. Our archives of choice are inorganic and biogenic carbonates, separated by wet sieving. We identified microfossil assemblages (fraction > 125 µm) and performed high-resolution oxygen isotope (delta18O) and elemental (Mg/Ca, Sr/Ca) analyses of the fraction food supply. These two aspects point to an increasing salinity in a shallowing lake. The delta18O values of inorganic carbonates are relatively low during the initial phase of Lake Van and increase abruptly (ca. 7‰) after 530 ka BP. At approximately the same time combination of Sr/Ca and Mg/Ca data suggest first occurrence of aragonite. Again, these findings suggest geochemical changes of the lake water concurrent with transition documented by microfossils. Comparison between Lake Van and Lake Ohrid (Lacey et al. 2016) delta18O data, precludes regional climate change (e.g.: increased evaporation) as the main driver of observed changes. With no evidence for increased volcanic or tectonic activity (e.g.: tephra layers, deformation structures, slumping) in the Lake Van sedimentary profile around 530 ka, it seems unlikely that a pyroclastic flow blocked the outflow of the lake. Alternatively, a portion of inflow has been diverged which might have caused a change in the hydrological balance and lake level falling below its outlet. However, as no geomorphological data confirming this scenario yet exist, it is only a

  1. Hydroclimatological influences on recently increased droughts in China's largest freshwater lake

    Science.gov (United States)

    Liu, Y.; Wu, G.

    2016-01-01

    Lake droughts are the consequence of climatic, hydrologic and anthropogenic influences. Quantification of droughts and estimation of the contributions from the individual factors are essential for understanding drought features and their causation structure. This is also important for policymakers to make effective adaption decisions, especially under changing climate. This study examines Poyang Lake, China's largest freshwater lake, which has been undergoing drastic hydrological alternation in the past decade. Standardized lake stage is used to identify and quantify the lake droughts, and hydroclimatic contributions are determined with a water budget analysis, in which absolute deficiency is defined in reference to normal hydrologic conditions. Our analyses demonstrate that in the past decade the lake droughts worsened in terms of duration, frequency, intensity and severity. Hydroclimatic contributions to each individual drought varied between droughts, and the overall contribution to the lake droughts in the past decade came from decreased inflow, increased outflow, and reduced precipitation and increased evapotranspiration in the lake region. The decreased inflow resulted mainly from reduced precipitation and less from increased evapotranspiration over the Poyang Lake basin. The increased outflow was attributable to the weakened blocking effects of the Yangtze River, which the Three Gorges Dam (TGD) established upstream. The TGD impoundments were not responsible for the increased number of drought events, but they may have intensified the droughts and changed the frequency of classified droughts. However, the TGD contribution is limited in comparison with hydroclimatic influences. Hence, the recently increased droughts were due to hydroclimatic effects, with a less important contribution from anthropogenic influences.

  2. Radiochronology of lake sediments

    Energy Technology Data Exchange (ETDEWEB)

    Erten, H.N. [Bilkent Univ., Ankara (Turkey). Dept. of Chemistry

    1997-01-01

    Sediment cores from Lakes Zurich, Constance, from the Sea of Marmara and from southern Turkey, northern Cyprus and eastern Spain were dated using natural {sup 210}Pb, fallout {sup 137}Cs and cosmic-ray produced {sup 7}Be radionuclides. Constant activity regions in the uppermost sections of sediments from Lake Zurich and the Sea of Marmara were attributed to post-depositional mobility of {sup 210}Pb in the former case and to bioturbation in the latter. A serious discrepancy exists between the {sup 210}Pb dating of Sea of Marmara sediments and those obtained by organic carbon based methods. The elements Zn, Cu, P and Pb were enriched in the upper sections of the sediment cores corresponding to the last 200 years. The increased metallurgical activities as a result of reforms in the Ottoman Army during the 18th century could be the most likely cause. (Author).

  3. Not so Great Lakes?

    Science.gov (United States)

    Showstack, Randy

    In 1965, Frank Sinatra won the Grammy Award for his album, "September of My Years;" "Early Bird," the first commercial communications satellite, was launched; and Dr. Martin Luther King, Jr. was arrested in Selma, Alabama, during demonstrations against voter-registration rules.The year 1965 was also the last time water levels in the U.S. Great Lakes were as low as they are now.

  4. Archaea in Yellowstone Lake.

    Science.gov (United States)

    Kan, Jinjun; Clingenpeel, Scott; Macur, Richard E; Inskeep, William P; Lovalvo, Dave; Varley, John; Gorby, Yuri; McDermott, Timothy R; Nealson, Kenneth

    2011-11-01

    The Yellowstone geothermal complex has yielded foundational discoveries that have significantly enhanced our understanding of the Archaea. This study continues on this theme, examining Yellowstone Lake and its lake floor hydrothermal vents. Significant Archaea novelty and diversity were found associated with two near-surface photic zone environments and two vents that varied in their depth, temperature and geochemical profile. Phylogenetic diversity was assessed using 454-FLX sequencing (~51,000 pyrosequencing reads; V1 and V2 regions) and Sanger sequencing of 200 near-full-length polymerase chain reaction (PCR) clones. Automated classifiers (Ribosomal Database Project (RDP) and Greengenes) were problematic for the 454-FLX reads (wrong domain or phylum), although BLAST analysis of the 454-FLX reads against the phylogenetically placed full-length Sanger sequenced PCR clones proved reliable. Most of the archaeal diversity was associated with vents, and as expected there were differences between the vents and the near-surface photic zone samples. Thaumarchaeota dominated all samples: vent-associated organisms corresponded to the largely uncharacterized Marine Group I, and in surface waters, ~69-84% of the 454-FLX reads matched archaeal clones representing organisms that are Nitrosopumilus maritimus-like (96-97% identity). Importance of the lake nitrogen cycling was also suggested by >5% of the alkaline vent phylotypes being closely related to the nitrifier Candidatus Nitrosocaldus yellowstonii. The Euryarchaeota were primarily related to the uncharacterized environmental clones that make up the Deep Sea Euryarchaeal Group or Deep Sea Hydrothermal Vent Group-6. The phylogenetic parallels of Yellowstone Lake archaea to marine microorganisms provide opportunities to examine interesting evolutionary tracks between freshwater and marine lineages.

  5. Great Lakes Energy Institute

    Energy Technology Data Exchange (ETDEWEB)

    Alexander, J. Iwan [Case Western Reserve Univ., Cleveland, OH (United States)

    2012-11-18

    The vision of the Great Lakes Energy Institute is to enable the transition to advanced, sustainable energy generation, storage, distribution and utilization through coordinated research, development, and education. The Institute will place emphasis on translating leading edge research into next generation energy technology. The Institute’s research thrusts focus on coordinated research in decentralized power generation devices (e.g. fuel cells, wind turbines, solar photovoltaic devices), management of electrical power transmission and distribution, energy storage, and energy efficiency.

  6. Audubon National Wildlife Refuge, Lake Nettie National Wildlife Refuge, Camp Lake Easement Refuge, Wintering River Easement Refuge, Cottonwood Lake Easement Refuge, Sheyenne Lake Easement Refuge : Narrative report : 1969

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Audubon National Wildlife Refuge (including Lake Nettie National Wildlife Refuge, Camp Lake Easement Refuge, Cottonwood Lake...

  7. Bear Lake-Minidoka - Phragmites Control

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Bear Lake: Phragmites patches were sprayed on the refuge & north of the lake proper. Minidoka: patches along the Snake River & Lake Walcott were treated with...

  8. Environmental Monitoring, Water Quality - Lakes Assessments - Attaining

    Data.gov (United States)

    NSGIC Education | GIS Inventory — This layer shows only attaining lakes of the Integrated List. The Lakes Integrated List represents lake assessments in an integrated format for the Clean Water Act...

  9. Paleoenvironments, Evolution, and Geomicrobiology in a Tropical Pacific Lake: The Lake Towuti Drilling Project (TOWUTI)

    Science.gov (United States)

    Vogel, Hendrik; Russell, James M.; Bijaksana, Satria; Crowe, Sean; Fowle, David; Haffner, Douglas; King, John; Marwoto, Ristiyanti; Melles, Martin; von Rintelen, Thomas; Stevenson, Janelle; Watkinson, Ian; Wattrus, Nigel

    2014-05-01

    Lake Towuti (2.5°S, 121°E) is a, 560 km2, 200-m deep tectonic lake at the downstream end of the Malili lake system, a set of five, ancient (1-2 MYr) tectonic lakes in central Sulawesi, Indonesia. Lake Towuti's location in central Indonesia provides a unique opportunity to reconstruct long-term paleoclimate change in a crucially important yet understudied region- the Indo-Pacific warm pool (IPWP), heart of the El Niño-Southern Oscillation. The Malili Lakes have extraordinarily high rates of floral and faunal endemism, and the lakes are surrounded by one of the most diverse tropical forests on Earth. Drilling in Lake Towuti will identify the age and origin of the lake and the environmental and climatic context that shaped the evolution of this unique lacustrine and terrestrial ecosystem. The ultramafic (ophiolitic) rocks and lateritic soils surrounding Lake Towuti provide metal substrates that feed a diverse, exotic microbial community, analogous to the microbial ecosystems that operated in the Archean Oceans. Drill core will provide unique insight into long-term changes in this ecosystem, as well as microbial processes operating at depth in the sediment column. High-resolution seismic reflection data (CHIRP and airgun) combined with numerous long sediment piston cores collected from 2007-2013 demonstrate the enormous promise of Lake Towuti for an ICDP drilling campaign. Well-stratified sequences of up to 150 m thickness, uninterrupted by unconformities or erosional truncation, are present in multiple sub-basins within Towuti, providing ideal sites for long-term environmental, climatic, and limnological reconstructions. Multiproxy analyses of our piston cores document a continuous and detailed record of moisture balance variations in Lake Towuti during the past 60 kyr BP. In detail our datasets show that wet conditions and rainforest ecosystems in central Indonesia persisted during Marine Isotope Stage 3 (MIS3) and the Holocene, and were interrupted by severe

  10. Reconstructing the lake-level history of former glacial lakes through the study of relict wave-cut terraces: the case of Lake Ojibway (eastern Canada)

    Science.gov (United States)

    Roy, Martin; Veillette, Jean; Daubois, Virginie

    2014-05-01

    known geodesic survey markers. Additional WCS were also measured with altimeters. The results suggest that Lake Ojibway experienced at least three different phases, at elevations of 283 m, 289 m, and 300 m (precision ± 0.5 m). For comparison, the near-maximum phase of Lake Ojibway (the only known phase) that was documented about 250 km to the NE would project at an elevation of about 385 m in the study area. Taken together, the position of these WCS in the landscape, their elevation and associated uplift gradients suggest that these lake levels were formed during episodes of long stands associated with late-stage phases of glacial Lake Ojibway. Overall, these results underlie the strong potential of the use of relict and discontinuous wave-cut terraces to reconstruct the lake-level history of former glacial lakes. This approach could also contribute to derive new estimates of meltwater volumes, a critical parameter in evaluating the impact of meltwater discharges on the late-glacial and deglacial climate.

  11. Algae Bloom in a Lake

    Directory of Open Access Journals (Sweden)

    David Sanabria

    2008-01-01

    Full Text Available The objective of this paper is to determine the likelihood of an algae bloom in a particular lake located in upstate New York. The growth of algae in this lake is caused by a high concentration of phosphorous that diffuses to the surface of the lake. Our calculations, based on Fick's Law, are used to create a mathematical model of the driving force of diffusion for phosphorous. Empirical observations are also used to predict whether the concentration of phosphorous will diffuse to the surface of this lake within a specified time and under specified conditions.

  12. Great Lakes' regional climate regimes

    Science.gov (United States)

    Kravtsov, Sergey; Sugiyama, Noriyuki; Roebber, Paul

    2016-04-01

    We simulate the seasonal cycle of the Great Lakes' water temperature and lake ice using an idealized coupled lake-atmosphere-ice model. Under identical seasonally varying boundary conditions, this model exhibits more than one seasonally varying equilibrium solutions, which we associate with distinct regional climate regimes. Colder/warmer regimes are characterized by abundant/scarce amounts of wintertime ice and cooler/warmer summer temperatures, respectively. These regimes are also evident in the observations of the Great Lakes' climate variability over recent few decades, and are found to be most pronounced for Lake Superior, the deepest of the Great Lakes, consistent with model predictions. Multiple climate regimes of the Great Lakes also play a crucial role in the accelerated warming of the lakes relative to the surrounding land regions in response to larger-scale global warming. We discuss the physical origin and characteristics of multiple climate regimes over the lakes, as well as their implications for a longer-term regional climate variability.

  13. Limited Regulation of Lake Erie.

    Science.gov (United States)

    1983-11-01

    Ontario,, Cedar Point in Ohio, Presque Isle in Pennsylvania and Hamlin in New York. Recreational boating is a significant activity on Lake Erie . Along...RD-Al47 936 LIMITED REGULATION OF LAKE ERIE (U) INTERNATIONAL LAKE i/i ERIE REGULATION STUDY BOARD NOV 83 UNCLASSIFIED F/G 13/2 N lhhhhh..hEmhhI...o lake Erie ’Governmen of 4,- % * L CTE " 84100400 .- Canad Unite Stte INTRNAIONL OIN COMISIO 4WD’ This document hais been ow for public rleoe and so

  14. THE LAKES IN ROMANIA - AN ACTUAL SYNTHESIS

    Directory of Open Access Journals (Sweden)

    Petre GÂŞTESCU

    2010-06-01

    Full Text Available The article offers a synthesis of the lakes of Romania. We addressed the following questions: genetic types of lakes, geographical distribution and their use in various fields of activities. Thus, in the territory of Romania is a large genetic diversity of lakes distributed on all major forms of relief and recovery in many economic areas. Romania is particularly present fluvial lakes, glacial lakes and anthropogenic lakes (especially reservoirs.

  15. Glacial lakes Buni and Jezerce: Albania

    OpenAIRE

    Milivojević Milovan; Kovačević-Majkić Jelena

    2005-01-01

    The paper presents glacial lakes and glacial relief forms at the foothill of the peak Maja Jezerce in Mt. Prokletije in Albania, near the border with Montenegro. The group of lakes Buni and Jezerce, which consists of six lakes and which genetically belongs to glacial-erosional lakes, is analyzed. Lakes are situated at the cirque bottom, between the moraines and limestone ridges. Except presented morphometric characteristics of lake basins, data about cirque are given, as well as the reconstru...

  16. THE LAKES IN ROMANIA - AN ACTUAL SYNTHESIS

    OpenAIRE

    Petre GÂŞTESCU

    2010-01-01

    The article offers a synthesis of the lakes of Romania. We addressed the following questions: genetic types of lakes, geographical distribution and their use in various fields of activities. Thus, in the territory of Romania is a large genetic diversity of lakes distributed on all major forms of relief and recovery in many economic areas. Romania is particularly present fluvial lakes, glacial lakes and anthropogenic lakes (especially reservoirs).

  17. Patrón reproductivo y talla media de madurez sexual de hembras de la langosta Panulirus gracilis (Decapoda: Palinuridae en Playa Lagarto, Guanacaste, Costa Rica

    Directory of Open Access Journals (Sweden)

    Helven Naranjo Madrigal

    2012-12-01

    Full Text Available La langosta Panulirus gracilis es importante como recurso pesquero de las comunidades costeras en el Pacífico Norte de Costa Rica. Debido a la importancia de actualizar el conocimiento relacionado con el patrón reproductivo de esta especie, se analizaron 357 especímenes de langostas P. gracilis hembras capturados mediante el buceo con compresor y el buceo a pulmón durante noviembre de 2007 a octubre del 2008 en Playa Lagarto. Se examinó la composición de las tallas por estrato de profundidad, el patrón mensual de la actividad reproductiva (IAR asociado al aumento relativo de la temperatura superficial del océano, y además se determinó la talla media de madurez sexual utilizando Modelos Lineales Generalizados. Los cuatro estados fisiológicos de madurez sexual mostraron que las hembras sin masa espermatófora y no ovígeras, presentaron las menores tallas con una media de 62.3mm de longitud cefalotoráxica (LC. Se observaron características de madurez sexual a partir de tallas muy bajas que van desde 30 a 50mm de LC, encontrándose la menor hembra ovígera reportada para esta especie de 35.8mm de LC y el mayor porcentaje de hembras maduras entre 70 y 80mm de LC. Los porcentajes del IAR se mantuvieron por encima del 50% durante el año, con excepción de los meses de octubre y enero. Además, se observó un aumento en el IAR que inició a partir de abril y continuó hasta agosto asociado a un relativo aumento en la temperatura a partir del mes de marzo, sin embargo esta relación no fue significativa (r²=0.49, p>0.05. No se descarta que la baja talla media de madurez sexual de 70.2mm de LC para P. gracilis en esta región sea causada por las prácticas de pesca. Se recomienda que se establezca una veda en la región de cinco meses (abril-agosto con el fin de proteger la estacionalidad reproductiva de la especie y promover un mayor reclutamiento a las áreas de pesca.

  18. Aplicación de directrices de calidad para la gestión y uso turístico de balnearios y playas

    Directory of Open Access Journals (Sweden)

    Claudia Toselli

    2011-01-01

    Full Text Available La aplicación de estándares de calidad es hoy un tema prioritario en las agendas del turismo internacional. Particularmente, en los últimos años, se ha dedicado mucho esfuerzo al establecimiento de códigos, criterios y sistemas de certificación turística para orientar tanto a los operadores turísticos y los actores locales, como a los propios turistas. En Argentina, ante la necesidad de abocarse a la mejora de la calidad ambiental y turística de la prestación de servicios en playas, los organismos nacionales rectores en materia de turismo, por un lado, y de medio ambiente, por el otro, aunaron esfuerzos para la elaboración de un conjunto de directrices que promovieran la gestión de calidad y el cuidado ambiental en áreas costeras y litorales fluviales, lacustres y marítimas. Estas directrices establecen una serie de lineamientos específicos al respecto, particularmente proveen un marco de referencia para la prestación de servicios en dichas áreas, y actualmente están incluidas en el Sistema Argentino de Calidad Turística. En esta línea, el objetivo de este trabajo ha sido conocer en qué grado estas directrices son aplicadas en balnearios en proceso de consolidación. Para ello se tomaron como estudio de caso dos balnearios de la provincia de Entre Ríos, ubicados en la localidad de Gualeguaychú sobre el margen del río del mismo nombre y bajo concesión por parte del sector privado. A partir de la aplicación de dichas directrices se reconoce que éstas son consideradas de manera parcial en ambos balnearios, lo cual puede encontrar explicación en la falta de obligatoriedad de las mismas. Por lo tanto, en esta directriz se indican algunas recomendaciones sobre las que los balnearios seleccionados tendrían que seguir trabajando y profundizando.

  19. Lake Charles CCS Project

    Energy Technology Data Exchange (ETDEWEB)

    Leib, Thomas [Leucadia Energy, LLC, Salt Lake City, UT (United States); Cole, Dan [Denbury Onshore, LLC, Plano, TX (United States)

    2015-06-30

    In late September 2014 development of the Lake Charles Clean Energy (LCCE) Plant was abandoned resulting in termination of Lake Charles Carbon Capture and Sequestration (CCS) Project which was a subset the LCCE Plant. As a result, the project was only funded through Phase 2A (Design) and did not enter Phase 2B (Construction) or Phase 2C (Operations). This report was prepared relying on information prepared and provided by engineering companies which were engaged by Leucadia Energy, LLC to prepare or review Front End Engineering and Design (FEED) for the Lake Charles Clean Energy Project, which includes the Carbon Capture and Sequestration (CCS) Project in Lake Charles, Louisiana. The Lake Charles Carbon Capture and Sequestration (CCS) Project was to be a large-scale industrial CCS project intended to demonstrate advanced technologies that capture and sequester carbon dioxide (CO2) emissions from industrial sources into underground formations. The Scope of work was divided into two discrete sections; 1) Capture and Compression prepared by the Recipient Leucadia Energy, LLC, and 2) Transport and Sequestration prepared by sub-Recipient Denbury Onshore, LLC. Capture and Compression-The Lake Charles CCS Project Final Technical Report describes the systems and equipment that would be necessary to capture CO2 generated in a large industrial gasification process and sequester the CO2 into underground formations. The purpose of each system is defined along with a description of its equipment and operation. Criteria for selection of major equipment are provided and ancillary utilities necessary for safe and reliable operation in compliance with environmental regulations are described. Construction considerations are described including a general arrangement of the CCS process units within the overall gasification project. A cost estimate is provided, delineated by system area with cost breakdown showing equipment, piping and materials

  20. Origin and age of the Lake Nyos maar, Cameroon

    Science.gov (United States)

    Lockwood, J.P.; Rubin, M.

    1989-01-01

    Lake Nyos occupies a young maar crater in the Precambrian granitic terrane of northwest Cameroon. The lake is partly surrounded by poorly consolidated, ultramafic nodule-bearing pyroclastic surge deposits that were explosively ejected from the Nyos crater at the time of its formation. Radiocarbon dates show that the maar probably formed about 400 years ago. Field evidence suggests that carbon dioxide could have been the principal volatile involved in the formation of the Nyos maar, and that the role of water may have been minor. The formation of the Nyos maar was preceded by a brief period of effusive basaltic volcanism, but the maar itself may have largely formed by cold, 'dry' explosive processes. Carbon dioxide may still be trapped interstitially in a diatreme inferred to underlie Lake Nyos; its gradual release into the waters of Lake Nyos may have set the stage for the tragic gas-release event of August 21, 1986. Only young maar lakes such as Nyos may pose a danger of future lethal gas releases. ?? 1989.

  1. Understanding cancer staging

    Science.gov (United States)

    ... provide more detailed information about the cancer stage. TNM Staging System The most common system for staging ... in the form of solid tumor is the TNM system. Most providers and cancer centers use it ...

  2. Cervical Cancer Stage IVA

    Science.gov (United States)

    ... historical Searches are case-insensitive Cervical Cancer Stage IVA Add to My Pictures View /Download : Small: 756x576 ... Large: 3150x2400 View Download Title: Cervical Cancer Stage IVA Description: Stage IVA cervical cancer; drawing and inset ...

  3. Quaternary lacustrine braid deltas on Lake General Carrera in southern Chile Deltas entrelazados lacustres del Cuaternario en el lago General Carrera, sur de Chile

    Directory of Open Access Journals (Sweden)

    C. Mike Bell

    2009-01-01

    Full Text Available A series of Quaternary lacustrine braid deltas on the shores of Lake General Carrera in southern Chile formed as a result of falls in lake level. Each delta comprises two components, the delta fan and the beach embayment, each in turn comprising an onshore subaerial and an offshore subaqueous element. The delta fans have a classic Gilbert form with a braided delta top and a steeply inclined delta front. Adjacent to the fans are concave beach embayments that formed parallel with the deltas as they prograded into the lake. The delta sediments consist predominantly of matrix- and clast-supported gravéis to a total composite thickness exceeding 400 m. The depositional environments are dominated by ephemeral river flooding and by storm-driven waves. Beach sediment is sorted, rounded, winnowed and transported alongshore by waves to fill the beach embayment with ridges of very well sorted and well-rounded gravel. A gently-dipping shoreface platform occurs up to 100 m offshore between the beach and the brink point. From the brink point, in water depth of about 8 m, sediment cascades down the steep delta front slope to form long foresets extending to the lake floor. The sedimentary successions therefore wedge in the opposite direction from those of tectonically controlled basin margins where fan growth keeps pace with basin subsidence.Una serie de deltas entrelazados lacustres, pertenecientes al Cuaternario, ubicados en las costas del lago General Carrera, en el sur de Chile, se formaron como resultado de caídas en el nivel del lago. Cada delta consta de dos componentes: el abanico deltaico y la zona de embahiamiento. Cada uno de ellos tiene, a su vez, un elemento subaéreo costero y un elemento subacuático. Los abanicos deltaicos tienen una forma Gilbert clásica con una parte superior de ríos entrelazados y un frente deltaico empinado. Adyacente a los abanicos aluviales existen bahías cóncavas de playa que se formaron de manera paralela a los

  4. LAKE AFDERA: A THREATENED SALINE LAKE IN ETHIOPIA

    African Journals Online (AJOL)

    lake's geological history of having marine inputs from the Red Sea (Gionfiantini et al., 1973). Unlike the other ... area) at the shore where one of the hot springs joins the lake. It is not known ... that goes to the Red Sea port of Assab. One of the ...

  5. Delineation of sympatric morphotypes of lake trout in Lake Superior

    Science.gov (United States)

    Moore, Seth A.; Bronte, Charles R.

    2001-01-01

    Three morphotypes of lake trout Salvelinus namaycush are recognized in Lake Superior: lean, siscowet, and humper. Absolute morphotype assignment can be difficult. We used a size-free, whole-body morphometric analysis (truss protocol) to determine whether differences in body shape existed among lake trout morphotypes. Our results showed discrimination where traditional morphometric characters and meristic measurements failed to detect differences. Principal components analysis revealed some separation of all three morphotypes based on head and caudal peduncle shape, but it also indicated considerable overlap in score values. Humper lake trout have smaller caudal peduncle widths to head length and depth characters than do lean or siscowet lake trout. Lean lake trout had larger head measures to caudal widths, whereas siscowet had higher caudal peduncle to head measures. Backward stepwise discriminant function analysis retained two head measures, three midbody measures, and four caudal peduncle measures; correct classification rates when using these variables were 83% for leans, 80% for siscowets, and 83% for humpers, which suggests the measures we used for initial classification were consistent. Although clear ecological reasons for these differences are not readily apparent, patterns in misclassification rates may be consistent with evolutionary hypotheses for lake trout within the Laurentian Great Lakes.

  6. Total Suspended Solids Effects on Freshwater Lake Biota Other than Fish.

    Science.gov (United States)

    Chapman, Peter M; Hayward, April; Faithful, John

    2017-08-17

    Protective benchmarks for the effects of total suspended solids (TSS) on freshwater aquatic biota primarily focus on fish; whether these benchmarks will also protect their prey or co-existing lower trophic level aquatic biota was uncertain. We conducted an extensive literature review of TSS effects on those organisms comprising the food webs upon which fish living in lakes depend: phytoplankton, zooplankton, periphyton, and benthic invertebrates. The available literature indicates that TSS benchmarks that protect sensitive life stages of lake fish will also protect their supporting food webs; in other words, the function of lake aquatic communities will be protected and maintained.

  7. Forecasting Lake-Effect Snow in the Great Lakes Using NASA Satllite Data

    Science.gov (United States)

    Cipullo, Michelle; Molthan, Andrew; Shafer, Jackie; Case, Jonathan; Jedlovec, Gary

    2011-01-01

    This slide presentation reviews the forecast of the lake effect snow in the Great Lakes region using models and infrared estimates of Great Lake Surface Temperatures (GLSTs) from the MModerate Resolution Imaging Spectroradiometer (MODIS) instrument on Terra and Aqua satellites, and other satellite data. This study analyzes Lake Erie and Lake Ontario which produce storm total snowfall ranged from 8-18 inches off of Lake Ontario and 10-12 inches off of Lake Erie for the areas downwind.

  8. Eutrophication in Poyang Lake (Eastern China) over the Last 300 Years in Response to Changes in Climate and Lake Biomass

    Science.gov (United States)

    Liao, Mengna; Yu, Ge; Guo, Ya

    2017-01-01

    Poyang Lake is suffering from persistent eutrophication, which is degrading the local ecosystem. A better understanding of the mechanisms that drive eutrophication in lake systems is essential to fight the ongoing deterioration. In this study, hydraulic residence time (HRT) was used to evaluate Poyang Lake’s trophic state. A hydrology and ecosystem forced model was constructed to simulate long-term changes in algae and aquatic plant biomass and total phosphorous (TP). A comparison analysis revealed that between 1812 and 1828 (i.e., a consistent-change stage), climate and hydrology were the main driving forces, while algae and aquatic plant biomass contributed only 20.9% to the trophic changes in Poyang Lake. However, between 1844 and 1860 the biomass predominated contributing 63.6%. This could be attributed to nutrient absorption by algae and aquatic plants. A correlation analysis of the water TP and algae and aquatic plant biomass revealed a strong positive relationship. However, the algae and aquatic plant growth rate tended to decline after the biomass reached half of the maximum. This research reconstructs the long-term trophic evolution of Poyang Lake and provides a better understanding of the relationship between climatic and hydrological changes and lake ecosystems. PMID:28046083

  9. Modeling hydrodynamics, temperature and water quality in Henry Hagg Lake, Oregon, 2000-2003

    Science.gov (United States)

    Sullivan, Annette B.; Rounds, Stewart A.

    2004-01-01

    The two-dimensional model CE-QUAL-W2 was used to simulate hydrodynamics, temperature, and water quality in Henry Hagg Lake, Oregon, for the years 2000 through 2003. Input data included lake bathymetry, meteorologic conditions, tributary inflows, tributary temperature and water quality, and lake outflows. Calibrated constituents included lake hydrodynamics, water temperature, orthophosphate, total phosphorus, ammonia, algae, chlorophyll a, zooplankton, and dissolved oxygen. Other simulated constituents included nitrate, dissolved and particulate organic matter, dissolved solids, and suspended sediment. Two algal groups (blue-green algae, and all other algae) were included in the model to simulate the lakes algal communities. Measured lake stage data were used to calibrate the lakes water balance; calibration of water temperature and water quality relied upon vertical profile data taken in the deepest part of the lake near the dam. The model initially was calibrated with data from 200001 and tested with data from 200203. Sensitivity tests were performed to examine the response of the model to specific parameters and coefficients, including the light-extinction coefficient, wind speed, tributary inflows of phosphorus, nitrogen and organic matter, sediment oxygen demand, algal growth rates, and zooplankton feeding preference factors.

  10. Conclusion: Ecology of Meromictic Lakes

    NARCIS (Netherlands)

    Gulati, Ramesh D.; Zadereev, Egor S.; Gulati, Ramesh D.; Zadereev, Egor S.; Degermendzhi, Andrei G.

    2017-01-01

    The term meromixis was introduced more than 80 years ago to denote lakes that do not annually mix completely. Since then our understanding of meromictic lakes has considerably advanced. Physical processes support the difference in water density between deep (monimolimnion ) and surface (mixolimnion

  11. Surface seiches in Flathead Lake

    Directory of Open Access Journals (Sweden)

    G. Kirillin

    2014-12-01

    Full Text Available Standing surface waves or seiches are inherent hydrodynamic features of enclosed water bodies. Their two-dimensional structure is important for estimating flood risk, coastal erosion and bottom sediment transport and for understanding shoreline habitats and lake ecology in general. In this work, we present analysis of two-dimensional seiche characteristics in Flathead Lake, Montana, USA, a large intermountain lake known to have high seiche amplitudes. To examine spatial characteristics of different seiche modes we used the original procedure of determining the seiche frequencies from the primitive equation model output with subsequent derivation of the spatial seiche structure at fixed frequencies akin the tidal harmonic analysis. The proposed procedure revealed specific seiche oscillation features in Flathead Lake including maximum surface level amplitudes of the first fundamental mode in straights around the largest island; several higher modes appearing locally in the vicinity of the river inflow; the "Helmholtz" open harbor mode, with the period approximately twice that of the longest seiche mode, generated by a large shallow bay connected to the main lake basin; and several rotating seiche modes potentially affecting the lake-wide circulation. We discuss the lake management problems related to of the spatial seiche distribution, such as shoreline erosion, floods and transport of sediments and invasive species in Flathead Lake.

  12. PYRAMID LAKE RENEWEABLE ENERGY PLAN

    Energy Technology Data Exchange (ETDEWEB)

    HIGH DESERT GEOCULTURE, LLC

    2009-06-06

    The Pyramid Lake Renewable Energy Plan covers these areas: energy potential (primarily focusing on geothermal resource potential, but also more generally addressing wind energy potential); renewable energy market potential; transmission system development; geothermal direct use potential; and business structures to accomplish the development objectives of the Pyramid Lake Paiute Tribe.

  13. Planktonic diatoms of Lake Ontario

    Science.gov (United States)

    Reinwand, Jerry F.

    1969-01-01

    The major species of diatoms in surface collections from Lake Ontario in September 1964 were Asterionella formosa, Fragilaria crotonensis, and Tabellaris fenestrata. Dominant species in the deep-water samples were Stephanodiscus astraea, S. astraea var. mintula, and F. crotonensis. The diatom flora in surface collections varied among several stations in the eastern end of the lake.

  14. Documentation of a computer program to simulate lake-aquifer interaction using the MODFLOW ground water flow model and the MOC3D solute-transport model

    Science.gov (United States)

    Merritt, Michael L.; Konikow, Leonard F.

    2000-01-01

    Heads and flow patterns in surficial aquifers can be strongly influenced by the presence of stationary surface-water bodies (lakes) that are in direct contact, vertically and laterally, with the aquifer. Conversely, lake stages can be significantly affected by the volume of water that seeps through the lakebed that separates the lake from the aquifer. For these reasons, a set of computer subroutines called the Lake Package (LAK3) was developed to represent lake/aquifer interaction in numerical simulations using the U.S. Geological Survey three-dimensional, finite-difference, modular ground-water flow model MODFLOW and the U.S. Geological Survey three-dimensional method-of-characteristics solute-transport model MOC3D. In the Lake Package described in this report, a lake is represented as a volume of space within the model grid which consists of inactive cells extending downward from the upper surface of the grid. Active model grid cells bordering this space, representing the adjacent aquifer, exchange water with the lake at a rate determined by the relative heads and by conductances that are based on grid cell dimensions, hydraulic conductivities of the aquifer material, and user-specified leakance distributions that represent the resistance to flow through the material of the lakebed. Parts of the lake may become ?dry? as upper layers of the model are dewatered, with a concomitant reduction in lake surface area, and may subsequently rewet when aquifer heads rise. An empirical approximation has been encoded to simulate the rewetting of a lake that becomes completely dry. The variations of lake stages are determined by independent water budgets computed for each lake in the model grid. This lake budget process makes the package a simulator of the response of lake stage to hydraulic stresses applied to the aquifer. Implementation of a lake water budget requires input of parameters including those representing the rate of lake atmospheric recharge and evaporation

  15. Lake-floor sediment texture and composition of a hydrothermally-active, volcanic lake, Lake Rotomahana

    Science.gov (United States)

    Pittari, A.; Muir, S. L.; Hendy, C. H.

    2016-03-01

    Young volcanic lakes undergo a transition from rapid, post-eruptive accumulation of volcaniclastic sediment to slower pelagic settling under stable lake conditions, and may also be influenced by sublacustrine hydrothermal systems. Lake Rotomahana is a young (129 year-old), hydrothermally-active, volcanic lake formed after the 1886 Tarawera eruption, and provides a unique insight into the early evolution of volcanic lake systems. Lake-bottom sediment cores, 20-46 cm in length, were taken along a transect across the lake and characterised with respect to stratigraphy, facies characteristics (i.e., grain size, componentry) and pore water silica concentrations. The sediments generally comprise two widespread facies: (i) a lower facies of light grey to grey, very fine lacustrine silt derived from the unconsolidated pyroclastic deposits that mantled the catchment area immediately after the eruption, which were rapidly reworked and redeposited into the lake basin; and (ii) an upper facies of dark, fine-sandy diatomaceous silt, that settled from the pelagic zone of the physically stable lake. Adjacent to sublacustrine hydrothermal vents, the upper dark facies is absent, and the upper part of the light grey to grey silt is replaced by a third localised facies comprised of hydrothermally altered pale yellow to yellowish brown, laminated silt with surface iron-rich encrustations. Microspheres, which are thought to be composed of amorphous silica, although some may be halloysite, have precipitated from pore water onto sediment grains, and are associated with a decrease in pore water silicon concentration. Lake Rotomahana is an example of a recently-stabilised volcanic lake, with respect to sedimentation, that shows signs of early sediment silicification in the presence of hydrothermal activity.

  16. L-Lake macroinvertebrate community

    Energy Technology Data Exchange (ETDEWEB)

    Specht, W.L.

    1996-06-01

    To characterize the present benthic macroinvertebrate community of L-Lake, Regions 5 and 7 of the reservoir were sampled in September 1995 at the same locations sampled in 1988 and 1989 during the L-Lake monitoring program. The macroinvertebrate community of 1995 is compared to that of 1988 and 1989. The species composition of L-Lake`s macroinvertebrate community has changed considerably since 1988-1989, due primarily to maturation of the reservoir ecosystem. L-Lake contains a reasonably diverse macroinvertebrate community that is capable of supporting higher trophic levels, including a diverse assemblage of fish species. The L-Lake macroinvertebrate community is similar to those of many other southeastern reservoirs, and there is no indication that the macroinvertebrate community is perturbed by chemical or physical stressors.

  17. Phosphorous Loading in Lake Champlain

    Science.gov (United States)

    Hoffman, H.; Halliday, B.; Lane, T.

    2016-12-01

    Phosphate movement from different sources into Lake Champlain is a problem. Excess phosphate generates algae growth causing eutrophication. This excessive growth known as algae blooms leads to poor water quality (State of Lake Report, 2015). Phosphate moves primarily by attachment to soil particles (Busman, Lamb, 09). Historically its movement has been limited to spring, summer and fall. Spring runoff is thought to contribute the most phosphate to Lake Champlain (Jensen, Tiessen, 11). With changes in global and local temperatures effecting weather patterns and the winter season, does phosphate continue to move into Lake Champlain during the winter months? Water samples from two tributaries to Lake Champlain were collected biweekly year around for the past three years. These samples were then tested for total suspended solids and phosphate levels. The results indicate that phosphate loading occurs throughout the year even during the winter months.

  18. Choking Lake Winnipeg

    Science.gov (United States)

    Byrne, J. M.; Little, L. J.; Dodgson, K. A.; MacDonald, R. J.; Graham, J.

    2009-12-01

    The problems of waterway eutrophication and coastal zone hypoxia are reaching epidemic proportions. Fresh water and coastal marine environments around the world are suffering unprecedented pollution loadings. We are developing an education program to address the dramatic need for public, community and K-12 education about the harsh impacts of elevated nutrient loads on fresh and marine water environments. The Lake Winnipeg watershed is adopted as the poster child of fresh water eutrophication in western North America. The watershed, one of the largest on the continent, is in rapid decline due to pollution, population pressures and water diversion. A concerted education program is needed to change personal and society actions that negatively impact the Winnipeg watershed; and the confluence of the watershed - Lake Winnipeg. But the education program goes beyond Lake Winnipeg. Negative impacts of nutrient loads are adversely affecting environments right to the oceans. Major dead zones that are expanding on our continental shelves due to nutrient overloading threaten to coalesce into extensive regions of marine life die-off. This presentation outlines the documentary education production process under development. We are building a series of Public Service Announcements (PSAs) for national television networks. The PSAs will direct educators, stakeholders and citizens to an associated website with educational video clips detailing the issues of eutrophication and hypoxia. The video clips or webisodes, present interviews with leading scientists. The discussions address the causes of the problems, and presents workable solutions to nutrient overloads from a variety of sources. The webisodes are accompanied by notes and advice to teachers on ways and means to use the webisodes in classrooms. The project is fully funed by a group of Canadian Community Foundations, with the understanding the work wil be available free to educators anywhere in the world. Our education

  19. 78 FR 53675 - Safety Zone; Lake Erie Heritage Foundation, Battle of Lake Erie Reenactment; Lake Erie, Put-in...

    Science.gov (United States)

    2013-08-30

    ... Lake Erie Reenactment; Lake Erie, Put-in-Bay, OH AGENCY: Coast Guard, DHS. ACTION: Temporary final rule... vicinity of Put-In-Bay, OH. This safety zone is intended to restrict vessels from a portion of Lake Erie during Battle of Lake Erie Reenactment near Put-In-Bay. This temporary safety zone is necessary...

  20. Concentración de metales pesados (Cu, Ni, Zn, Cd, Pb en la biota y sedimentos de una playa artificial, en la bahía San Jorge 23°S, norte de Chile Heavy metals concentration (Cu, Ni, Zn, Cd, Pb, in biota and sediments of an artificial beach, in San Jorge bay 23°S, northern Chile

    Directory of Open Access Journals (Sweden)

    Gabriel Castro

    2012-07-01

    Full Text Available Se evaluó el contenido de metales pesados (Cu, Ni, Zn, Cd, Pb en la biota y el sedimento de una playa artificial (Paraíso y una playa natural (El Lenguado, ubicadas en la bahía San Jorge, norte de Chile. Los resultados fueron utilizados para comparar ambos sistemas, el grado de cumplimiento de la normativa ambiental nacional e internacional, y el efecto de la construcción de la playa artificial sobre el nivel de contaminación por metales existentes históricamente en esa zona. En cada playa se ubicaron estaciones equidistantes que abarcaron desde el intermareal hasta el submareal de las cuales fueron extraídos los organismos. Se tomaron muestras de sedimento en cada playa y se determinaron las pendientes con el método de Emery. El análisis granulométrico evidenció el predominio de arena media en playa El Lenguado, y arena media y fina en playa Paraíso. El contenido de materia orgánica fue mayor en El Lenguado. En playa Paraíso se determinaron cinco phylum/superclase agrupados en 19 taxa, mientras que en El Lenguado se encontraron cuatro phylum/superclase agrupados en cc taxa. El contenido de metales en sedimentos y en la mayoría de organismos presentó valores mayores en playa Paraíso. Estos resultados, junto a las normas de calidad chilenas y norteamericanas, sugieren un evidente deterioro en la calidad ambiental de playa Paraíso lo que se demostró por un incremento en las concentraciones de estos metales desde su construcción, los que sobrepasan los límites establecidos por ambas normas.It was evaluated the heavy metal content (Cu, Ni, Zn, Cd, Pb in biota and sediment of an artificial beach (Paraíso and a natural beach (El Lenguado, both located in San Jorge bay, northern Chile. The results were used to compare both systems, the degree of fulfillment of national and international environmental regulations, and the effect of the construction of the artificial beach on the level of metal contamination historically existing in

  1. Between Stage and Screen

    NARCIS (Netherlands)

    Tornqvist, Egil

    1996-01-01

    Ingmar Bergman is worldwide known as a film and stage director. Yet no-one has attempted to compare his stage and screen activities. In Between stage and screen Egil Tornqvist examines formal and thematical correspondences and differences between a number of Bergman's stage, screen, and radio produc

  2. 14 CFR 93.69 - Special requirements, Lake Campbell and Sixmile Lake Airports.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 2 2010-01-01 2010-01-01 false Special requirements, Lake Campbell and... Anchorage, Alaska, Terminal Area § 93.69 Special requirements, Lake Campbell and Sixmile Lake Airports. Each person operating an aircraft to or from Lake Campbell or Sixmile Lake Airport shall conform to the flow...

  3. La dispensarización en el policlínico universitario docente de Playa un año después de la reorganización Dispensarization in the "Playa" teaching and university polyclinic after one year of the reorganization

    Directory of Open Access Journals (Sweden)

    Leonardo Antonio Cuesta Mejías

    2011-03-01

    Full Text Available Introducción: aunque concebida originalmente en la antigua Unión Soviética, la dispensarización en nuestro país se llegó a constituir, junto con el Análisis de la Situación de Salud, en elementos fundamentales de la medicina familiar, en otras palabras, en la organización del trabajo del Médico de Familia. Objetivos: determinar la situación de la dispensarización a un año de haberse implementado la reorganización de nuestros consultorios de medicina familiar. Métodos: se desarrolló un estudio descriptivo de corte transversal de una muestra tomada al azar, 400 de las historias clínicas individuales del total de pacientes dispensarizados con enfermedades crónicas no transmisibles en los 9 consultorios del Médico y Enfermera de Familia del Policlínico Universitario Docente de Playa. Se revisaron igualmente las historias de salud familiar de los pacientes cuyas historias individuales seleccionamos. Se obtuvo también información de los registros del Departamento de Estadísticas del propio policlínico, con relación a la actividad realizada por los equipos básicos de salud en consulta y en terreno en el mes de enero del presente año. Resultados: la mayoría de los pacientes pertenecen a los grupos de edades por encima de los 50 años, igualmente al sexo femenino y sufren de una sola enfermedad crónica. La hipertensión arterial es la enfermedad crónica que más los afecta, seguida de la diabetes mellitus. El 40 % de los pacientes no ha recibido control, y el 81 % de los pacientes ha sido consultado, ambas situaciones en el último año. Conclusiones: la dispensarización ha mejorado, pero se mantiene presentando un grupo importante de insuficiencias. La reorganización ofrece un potencial aún sin explotar para garantizar una mejor e integral atención médica a nuestra población.Introduction: although originally conceived in the former Soviet Union, the dispensarization in our country was implemented together with the

  4. Less Mixing Can Affect Lake s Ecosystem

    Institute of Scientific and Technical Information of China (English)

    E.Sohn

    2005-01-01

    Lakescanbelikebowlsofsoupinthemicrowave:Theyneedalittlestirringeverynowandthen.Otherwise,alltheheatendsupontop.That’sexactlywhat’shappenedinrecentyearstoAfrica'sLakeTanganyika,scientistsarereporting.Risingwatertemperatureshaveinterferedwiththelake’snormal

  5. TOXAPHENE IN THE GREAT LAKES. (R825246)

    Science.gov (United States)

    This paper presents the most current data for toxaphene in the water, sediments, and biota of the Laurentian Great Lakes of North America. Concentrations in water range from 1.1 ng/L in Lake Superior to 0.17 ng/L in Lake Ontario. Lake Superior has the highest water concentrati...

  6. Challenges and opportunities for integrating lake ecosystem modelling approaches

    Science.gov (United States)

    Mooij, Wolf M.; Trolle, Dennis; Jeppesen, Erik; Arhonditsis, George; Belolipetsky, Pavel V.; Chitamwebwa, Deonatus B.R.; Degermendzhy, Andrey G.; DeAngelis, Donald L.; Domis, Lisette N. De Senerpont; Downing, Andrea S.; Elliott, J. Alex; Ruberto, Carlos Ruberto; Gaedke, Ursula; Genova, Svetlana N.; Gulati, Ramesh D.; Hakanson, Lars; Hamilton, David P.; Hipsey, Matthew R.; Hoen, Jochem 't; Hulsmann, Stephan; Los, F. Hans; Makler-Pick, Vardit; Petzoldt, Thomas; Prokopkin, Igor G.; Rinke, Karsten; Schep, Sebastiaan A.; Tominaga, Koji; Van Dam, Anne A.; Van Nes, Egbert H.; Wells, Scott A.; Janse, Jan H.

    2010-01-01

    A large number and wide variety of lake ecosystem models have been developed and published during the past four decades. We identify two challenges for making further progress in this field. One such challenge is to avoid developing more models largely following the concept of others ('reinventing the wheel'). The other challenge is to avoid focusing on only one type of model, while ignoring new and diverse approaches that have become available ('having tunnel vision'). In this paper, we aim at improving the awareness of existing models and knowledge of concurrent approaches in lake ecosystem modelling, without covering all possible model tools and avenues. First, we present a broad variety of modelling approaches. To illustrate these approaches, we give brief descriptions of rather arbitrarily selected sets of specific models. We deal with static models (steady state and regression models), complex dynamic models (CAEDYM, CE-QUAL-W2, Delft 3D-ECO, LakeMab, LakeWeb, MyLake, PCLake, PROTECH, SALMO), structurally dynamic models and minimal dynamic models. We also discuss a group of approaches that could all be classified as individual based: super-individual models (Piscator, Charisma), physiologically structured models, stage-structured models and trait-based models. We briefly mention genetic algorithms, neural networks, Kalman filters and fuzzy logic. Thereafter, we zoom in, as an in-depth example, on the multi-decadal development and application of the lake ecosystem model PCLake and related models (PCLake Metamodel, Lake Shira Model, IPH-TRIM3D-PCLake). In the discussion, we argue that while the historical development of each approach and model is understandable given its 'leading principle', there are many opportunities for combining approaches. We take the point of view that a single 'right' approach does not exist and should not be strived for. Instead, multiple modelling approaches, applied concurrently to a given problem, can help develop an integrative

  7. Analysis of Drought in Poyang Lake

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    [Objective] The drought situation and causes in Poyang Lake were analyzed.[Method] In response to the drought in Poyang Lake in ten years ago and in recent 10 years,the causes of drought in Poyang Lake were discussed.[Result] Drought occurred frequently in Poyang Lake and the consecutive serious drought occurred now and then.The water level in Poyang Lake since 21st century was lower.The drought in Poyang Lake was due to reduction of precipitation,low water level in Yangtze River and "five lakes",hydraulic ...

  8. The Great Lakes' regional climate regimes

    Science.gov (United States)

    Sugiyama, Noriyuki

    For the last couple of decades, the Great Lakes have undergone rapid surface warming. In particular, the magnitude of the summer surface-warming trends of the Great Lakes have been much greater than those of surrounding land (Austin and Colman, 2007). Among the Great Lakes, the deepest Lake Superior exhibited the strongest warming trend in its annual, as well as summer surface water temperature. We find that many aspects of this behavior can be explained in terms of the tendency of deep lakes to exhibit multiple regimes characterized, under the same seasonally varying forcing, by the warmer and colder seasonal cycles exhibiting different amounts of wintertime lake-ice cover and corresponding changes in the summertime lake-surface temperatures. In this thesis, we address the problem of the Great Lakes' warming using one-dimensional lake modeling to interpret diverse observations of the recent lake behavior. (Abstract shortened by ProQuest.).

  9. Development of Salt Lake Resources in Qaidamu Kicks off

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    @@ In March 2003, Qinghai Provincial Government and the related enterprises signed the agreements with China International Trust and Investment Company (CITIC) on joint development of the rich salt lake resources in Qaidamu basin over the next five years. Under the agreements, CITIC will budget 4.2 billion yuan to construct a large-scale chemical complex in two stages, which will annually produce 35,000 tons of lithium borate, 1 million tons of potassium sulfate and 35,000 tons of boric acid. The first-stage project will come into operation by 2005.

  10. Rehabilitation of Delavan Lake, Wisconsin

    Science.gov (United States)

    Robertson, Dale M.; Goddard, Gerald L.; Helsel, D.R.; MacKinnon, Kevin L.

    2009-01-01

    A comprehensive rehabilitation plan was developed and implemented to shift Delavan Lake, Wisconsin, from a hypereutrophic to a mesotrophic condition. The plan was threefold: (1) reduce external phosphorus (P) loading by applying Best Management Practices in the watershed, enhance an existing wetland, and short-circuit the inflows through the lake, (2) reduce internal P loading by treating the sediments with alum and removing carp, and (3) rehabilitate the fishery by removing carp and bigmouth buffalo and adding piscivores (biomanipulation). The first and second parts of the plan met with only limited success. With only minor reductions in internal and external P loading, P concentrations in the lake returned to near pre-treatment concentrations. The intensive biomanipulation and resulting trophic cascade (increased piscivores, decreased planktivores, increased large zooplankton populations, and reduced phytoplankton populations) eliminated most of the original problems in the lake (blue-green algal blooms and limited water clarity). However, now there is extensive macrophyte growth and abundant filamentous algae. Without significantly reducing the sources of the problems (high P loading) in Delavan Lake, the increased water clarity may not last. With an improved understanding of the individual components of this rehabilitation program, better future management plans can be developed for Delavan Lake and other lakes and reservoirs with similar eutrophication problems.

  11. Possible temperate lakes on Titan

    Science.gov (United States)

    Vixie, Graham; Barnes, Jason W.; Jackson, Brian; Rodriguez, Sébastien; Le Mouélic, Stéphane; Sotin, Christophe; MacKenzie, Shannon; Wilson, Paul

    2015-09-01

    We analyze southern mid-latitude albedo-dark features on Titan observed by Cassini's Visual and Infrared Mapping Spectrometer (VIMS). In exploring the nature of these features we consider their morphology, albedo, and specular reflectivity. We suggest that they represent candidates for potential temperate lakes. The presence of lakes at the mid-latitudes would indicate that surface liquid can accumulate and remain stable away from Titan's poles. Candidate lakes were identified by looking for possible shorelines with lacustrine morphology. Then, we applied an atmospheric correction that empirically solved for their surface albedo. Finally, we looked for a specular reflection of the sky in the identified candidates. Using this prescription, we find two candidates that remain as potential temperature lakes. If candidate features do represent temperate lakes on Titan, they have implications for formation mechanisms such as clouds and rainfall or, in low elevation areas, percolation and subsurface flow. Clouds were observed near candidate lake locations on the T66 flyby and this latitude band showed many clouds during southern summer. Our techniques can be applied to areas of Titan that lack RADAR coverage to search for mid- and low-latitude lakes in the future.

  12. LONG-TERM CHANGES IN THE LARGE LAKE ECOSYSTEMS UNDER POLLUTION: THE CASE OF THE NORTH-EAST EUROPEAN LAKES

    Directory of Open Access Journals (Sweden)

    Tatyana Moiseenko

    2012-01-01

    Full Text Available A retrospective analysis of aquatic ecosystem long-term changes in the Russian large lakes: Ladoga, Onega, and Imandra, is given. The lakes in the past were oligotrophic and similar in their origin, water chemistry and fauna. The ecosystems transformed under the impact of pollution with toxic substances and nutrients. There are three stages of ecosystem quality: background parameters and degradation and recovery trends after the decrease of the toxic stress. On the stage of degradation, species abundance and community biodiversity were decreased. Eurybiontic species abundance and biomass were increased due to lack of competitive connections in toxic conditions and biogenic inflow. Small forms of organisms (r-strategists, providing more rapid biomass turnover in ecosystem, dominated in the formed plankton communities. On the stage of decrease of the toxic pollution, the lakes recolonization with northern species occurs, which is confirmed by replacement of dominating complexes, increasing index of plankton community biodiversity, and the rise of the mass of individual organisms of the communities. Accumulated nutrients in ecosystems are efficiently utilized at the upper trophic level. The ecosystem state after decrease of the toxic impact indicates formation of its mature and more stable modification, which differs from a natural one.

  13. Influence of riverine outputs on sandy beaches of Higuerote, central coast of Venezuela Influencia de aportes fluviales en playas arenosas de Higuerote, costa central de Venezuela

    Directory of Open Access Journals (Sweden)

    Antonio Herrera

    2011-01-01

    Full Text Available The influence of riverine outputs from the Tuy River on the coastal processes of near sandy beaches was assessed by measuring the physical and chemical characteristics of water and sediment samples at eight sites along the north central Venezuelan coast and from the rivers that flow through this región into the sea (Tuy, Capaya, Curiepe during two field surveys. In addition, the behavior of the Tuy River discharge plume was evaluated using remote sensors, and its effect on the population abundance and size structure of the clam Tivela mactroides was determined. Of the three rivers evaluated, the Tuy River had the highest impact on the coastal zone (789.15 ± 190.63 km² in terms of flow rate (246.39 m³ s-1, nutrients (659.61 ± 503.27 g s-1total nitrogen; 52 ± 53.09 g s-1 total phosphorus and sedimentary material (9320.84 ± 9728.15 g s-1. The variables measured (salinity, total nitrogen and phosphorus, pH, turbidity, and total organic carbon showed a spatial gradient along the coast. Tivela mactroides had the highest biomass and density (9126.8 ± 1562 g m-2; 9222.22 ± 1976.72 ind m-2 at the sites farthest from the river mouths and smaller sizes (Para evaluar los aportes del río Tuy sobre los procesos costeros en playas arenosas cercanas, se examinó en dos campañas de muestreo, las características físicas y químicas a nivel de agua y sedimento en ocho estaciones ubicadas a lo largo de la costa centro norte de Venezuela, el cauce de los ríos que allí desembocan (Tuy, Capaya, Curiepe, además del comportamiento de la pluma del río Tuy mediante sensores remotos y su influencia sobre las poblaciones de la almeja Tivela mactroides en cuanto a abundancia y estructura de talla. El río Tuy tuvo mayor predominio sobre la zona costera (789,15 ± 190,63 km , presentó el mayor aporte líquido (246,39 m³ s-1, de nutrientes (659,61 ± 503,27 g s-1 nitrógeno total; 52 ± 53,09 g s-1fósforo total y material sedimentario (9320,84 ± 9728,15 g

  14. Biocenosis de Bivalvia y Polyplacophora del intermareal rocoso en playa Tlacopanocha, Acapulco, Guerrero, México Polyplacophora and Bivalvia biocenosis at rocky intertidal Tlacopanocha beach, Acapulco, Guerrero, Mexico

    Directory of Open Access Journals (Sweden)

    Lizeth Galeana-Rebolledo

    2012-11-01

    Full Text Available El Estado de Guerrero, México, tiene regiones marinas prioritarias para la conservación de su biodiversidad y la información acerca de la diversidad de moluscos es escasa, por lo que es necesario realizar inventarios de especies, estudios de ecología de poblaciones y comunidades. Este estudio se efectuó en el intermareal rocoso de la playa Tlacopanocha. Los objetivos fueron: determinar la riqueza, densidad y diversidad de especies; analizar la composición de especies y estructura de tallas. El área de muestreo fue de 10 m² y la unidad de muestreó fue de 1 m². Se identificaron 35 especies, de las cuales tres son nuevos registros para el intermareal rocoso de Guerrero: las familias mejor representadas en riqueza de especies fueron Ischnochitonidae y Arcidae, y en abundancia Chitonidae y Chamidae; la densidad fue de 31,60 ind m-2. Polyplacophora presentó 42,9% de especies dominantes y Bivalvia 19,0%. Chama corallina presentó la mayor talla en longitud y Chama sordida en ancho. La riqueza de especies de moluscos registrada se considera alta y corresponde a lo esperado para un sustrato rocoso en zona tropical. Polyplacophora presentó alta composición de especies, que podría ser resultado de la adaptación de los organismos a las condiciones dinámicas del intermareal rocoso. Los nuevos registros indican la importancia de los inventarios de especies y también del conocimiento de las poblaciones y comunidades de la fauna marina de Guerrero.The State of Guerrero, Mexico, has priority marine areas for conservation of its biodiversity, but information concerning diversity of mollusks is limited, so it is convenient to carry out species inventories, studies of populations and community ecology. This study was conducted in the intertidal rocky beach Tlacopanocha. The objectives were to determine richness, density and species diversity, analyze the species composition and size structure. The sampling area was 10 m² and the sampling unit was

  15. Microplastics in Taihu Lake, China.

    Science.gov (United States)

    Su, Lei; Xue, Yingang; Li, Lingyun; Yang, Dongqi; Kolandhasamy, Prabhu; Li, Daoji; Shi, Huahong

    2016-09-01

    In comparison with marine environments, the occurrence of microplastics in freshwater environments is less understood. In the present study, we investigated microplastic pollution levels during 2015 in Taihu Lake, the third largest Chinese lake located in one of the most developed areas of China. The abundance of microplastics reached 0.01 × 10(6)-6.8 × 10(6) items/km(2) in plankton net samples, 3.4-25.8 items/L in surface water, 11.0-234.6 items/kg dw in sediments and 0.2-12.5 items/g ww in Asian clams (Corbicula fluminea). The average abundance of microplastics was the highest in plankton net samples from the southeast area of the lake and in the sediments from the northwest area of the lake. The northwest area of the lake was the most heavily contaminated area of the lake, as indicated by chlorophyll-α and total phosphorus. The microplastics were dominated by fiber, 100-1000 μm in size and cellophane in composition. To our best knowledge, the microplastic levels measured in plankton net samples collected from Taihu Lake were the highest found in freshwater lakes worldwide. The ratio of the microplastics in clams to each sediment sample ranged from 38 to 3810 and was negatively correlated to the microplastic level in sediments. In brief, our results strongly suggest that high levels of microplastics occurred not only in water but also in organisms in Taihu Lake.

  16. Monitoring Change in Great Salt Lake

    Science.gov (United States)

    Naftz, David; Angeroth, Cory; Freeman, Michael; Rowland, Ryan; Carling, Gregory

    2013-08-01

    Great Salt Lake is the largest hypersaline lake in the Western Hemisphere and the fourth largest terminal lake in the world (Figure 1). The open water and adjacent wetlands of the Great Salt Lake ecosystem support millions of migratory waterfowl and shorebirds from throughout the Western Hemisphere [Aldrich and Paul, 2002]. In addition, the area is of important economic value: Brine shrimp (Artemia franciscana) residing in Great Salt Lake support an aquaculture shrimp cyst industry with annual revenues as high as $60 million.

  17. Advance and application of lake optics research

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    The mainstreams of lake optics research in recent decades include optical properties of lakewater,observation, transmission and calculation of underwater radiation, determination of absorption coefficient S of yellow substance, influence of UV-B radiation of lake primary productivity by bio-optical model. Major lake optics applications, such as calculation of lake primary productivity and chl-a, analysis of factors restricting eutrophication, and protection against lake eutrophication are summarized.

  18. Biogeochemistry of Kenyan Rift Valley Lake Sediments

    Science.gov (United States)

    Grewe, Sina; Kallmeyer, Jens

    2013-04-01

    The numerous lakes in the Kenyan Rift Valley show strong hydrochemical differences due to their varying geologic settings. There are freshwater lakes with a low alkalinity like Lake Naivasha on the one hand and very salt-rich lakes with high pH values like Lake Logipi on the other. It is known that the underlying lake sediments are influenced by the lake chemistry and by the microorganisms in the sediment. The aim of this work is to provide a biogeochemical characterization of the lake sediments and to use these data to identify the mechanisms that control lake chemistry and to reconstruct the biogeochemical evolution of each lake. The examined rift lakes were Lakes Logipi and Eight in the Suguta Valley, Lakes Baringo and Bogoria south of the valley, as well as Lakes Naivasha, Oloiden, and Sonachi on the Kenyan Dome. The porewater was analysed for different ions and hydrogen sulphide. Additionally, alkalinity and salinity of the lake water were determined as well as the cell numbers in the sediment, using fluorescent microscopy. The results of the porewater analysis show that the overall chemistry differs considerably between the lakes. In some lakes, concentrations of fluoride, chloride, sulphate, and/or hydrogen sulphide show strong concentration gradients with depth, whereas in other lakes the concentrations show only minor variations. Fluoride is present in all lakes; the lowest concentration is found in Lake Oloiden (60 - 90 mg/l), the highest one in Lake Bogoria (1,025 - 1,930 mg/l). The lakes show also large differences in sulphate concentrations. The values vary between 2 mg/l in Lake Baringo and 15,250 mg/l in Lake Eight. In all cores, sulphate concentration does not change significantly with depth; however, there is a distinct peak in each core, raising the question of synchronicity. As expected, chloride concentrations correlate with total salinity. There is no hydrogen sulphide present in the porewater of Lakes Naivasha, Baringo, and Oloiden, whereas in

  19. 2010 Great Lakes Restoration Initiative Bathymetric Lidar: Lake Superior

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The data contained in this file contain hydrographic and topographic data collected by the Fugro LADS Mk II system along the Lake Superior coast of Minnessota,...

  20. Bathymetric maps of Lake Becharof and the Ugashik Lakes

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — In order to understand the production of smolts in a sockeye salmon nursery lake, it is mandatory to produce a bathymetric map. This must be detailed enough so that...

  1. Lake trout in the Great Lakes: Basin-wide stock collapse and binational restoration

    Science.gov (United States)

    Hansen, Michael J.; Taylor, William W.; Ferreri, C. Paola

    1999-01-01

    The lake trout (Salvelinus namaycush) was important to the human settlement of each of the Great Lakes, and underwent catastrophic collapses in each lake in the nineteenth and twentieth centuries. The timing of lake trout stock collapses were different in each lake, as were the causes of the collapses, and have been the subject of much scientific inquiry and debate. The purpose of this chapter is to summarize and review pertinent information relating historical changes in Great Lakes lake trout stocks, binational efforts to restore those stocks, and progress toward stock restoration. This presentation attempts to generalize patterns across the Great Lakes, rather than to focus within each lake. Lake specific analyses have been used to understand lake specific causes and effects, but there is continuing debate about some of these causes and effects. A basinwide review may suggest mechanisms for observed changes that are not evident by lake specific analysis.

  2. Chase Lake Wetland Management District, Chase Lake Prairie Project: Annual narrative report - 1993

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Chase Lake WMD, Chase Lake Prairie Project, and Halfway Lake NWR outlines Refuge accomplishments during the 1993 calendar year. The...

  3. Chase Lake Wetland Management District, Chase Lake Prairie Project: Annual narrative report: Calendar year 1994

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Chase Lake WMD, Chase Lake Prairie Project, and Halfway Lake NWR outlines Refuge accomplishments during the 1994 calendar year. The...

  4. Annual narrative report 1995: Chase Lake Wetland Management District, Chase Lake Prairie Project

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Chase Lake WMD, Chase Lake Prairie Project, and Halfway Lake NWR outlines Refuge accomplishments during the 1995 calendar year. The...

  5. Characteristics and ontogeny of oligotrophic hardwater lakes in the Forsmark area, central Sweden

    Energy Technology Data Exchange (ETDEWEB)

    Brunberg, A.K.; Blomqvist, P. [Uppsala Univ. (Sweden). Dept. of Limnology

    1999-12-01

    This is the first part of a report characterising the lakes of Uppsala county, with special emphasis on the coastal lakes in the Forsmark area.The aim of the study is to characterise different main types of lakes within the Forsmark area and to create a basis for prediction of their ontogeny, that can be used also for new lakes which due to shoreline displacement will be formed during the next 10 000 years. Areas where future research is needed to fully understand the functioning of the lake ecosystems and their ontogeny should also be identified. This first part of the study identifies and describes one of the most common lake types in the area, the oligotrophic hardwater lake. The geology in the catchments of the Forsmark area includes a bedrock dominated by granites and gneisses, covered by calcareous glacial till and postglacial clay. The catchments are dominated by forest, and the oligotrophic hardwater lakes are to a large extent surrounded by mires. Inflow as well as outflow of water is often diffuse, via the surrounding mire. The lakes are small and shallow, with nutrient poor and highly alkaline water. Three key habitats have been identified within the lakes; the pelagic zone, characterised by low production of biota;, the presumably moderately productive emergent macrophyte zone, dominated by Sphagnum and Phragmites;, and the light exposed soft-bottom zone with Chara meadows and an unusually rich and presumably highly productive microbial sediment community. The oligotrophic hardwater lakes have their origin as depressions in the bottom of the Baltic Sea, which are successively transported upwards due to the land-rise process in the area. As the basins are isolated from the sea , a gradual change from a brackish to freshwater conditions occur. When the lakes have become completely isolated, the oligotrophic hardwater stage follows, due to inflow of carbonate-rich and well buffered groundwater. In the next successional stage, Sphagnum mosses start to

  6. Comparative studies of underwater light regimes in lakes of the East-Suwałki Lakeland

    Directory of Open Access Journals (Sweden)

    Borowiak Dariusz

    2016-12-01

    Full Text Available Secchi disc transparency and optical properties of water, based on measurements for downward irradiance using an underwater radiometer PER-700, were studied in 23 lakes of the Suwałki Landscape Park (SLP in 2013. Measurements of optically significant constituents of water were also performed (YSI EXO-2 and analysed. Data on water transparency from published studies were used to assess long-term changes in the optical conditions in the deepest water body in Poland – Lake Hańcza. In terms of the optical characteristics of the water, the analysed SLP lakes can essentially be divided into two distinct groups representing different optical lake types. These are optical categories of lakes most common in Poland, namely types II and IIIb. Regional equations describing the relationships between the attenuation coefficient for downward irradiance as well as optically significant constituents of water were developed. The optical properties of the SLP lakes are mainly affected by suspended solids, mostly phytoplankton. Interannual fluctuations in Sechi disc transparency, as well as the attenuation coefficient for downward irradiance and other apparent optical properties of mid-summer water calculated from it, are determined by the spring thermal conditions and intensity of phytoplankton blooms during this period. Application of the attenuation coefficient for downward irradiance as a criterion for the assessment of the trophic status of the SLP lakes indicates that these are generally eutrophic lakes. The largest and deepest lakes of the park, however, are mesotrophic. Lake Hańcza is currently in the stage of α-mesotrophy.

  7. Estrategias cotidianas de las familias en situación vulnerable para la protección, defensa y garantía de los derechos humanos (DDHH en el corregimiento de la playa de Barranquilla (Colombia

    Directory of Open Access Journals (Sweden)

    José Amar Amar

    2004-01-01

    Full Text Available Esta investigación tiene como objetivo identificar, comprender y explicar las estrategias cotidianas por las familias en situación vulnerable, para la protección, defensa y garantía de los derechos humanos (DDHH, en el corregimiento de La Playa de Barranquilla (Colombia. Este trabajo se propone contribuir al conocimiento sobre el significado del derecho que le dan las personas desde su cotidianidad, teniendo como base la narración de sus experiencias más cercanas a la violación o abuso de los derechos. La propuesta metodológica se orientó desde el método narrativo, que se caracteriza por relatar, comunicar o contar acciones y acontecimientos reales realizados por personajes que intervienen en un ambiente específico

  8. Use of a seismic air gun to reduce survival of nonnative lake trout embryos: A tool for conservation?

    Science.gov (United States)

    Cox, B.S.; Dux, A.M.; Quist, M.C.; Guy, C.S.

    2012-01-01

    The detrimental impacts of nonnative lake trout Salvelinus namaycush in the western USA have prompted natural resource management agencies in several states to implement lake trout suppression programs. Currently, these programs rely on mechanical removal methods (i.e., gill nets, trap nets, and angling) to capture subadult and adult lake trout. We conducted a study to explore the potential for using high-intensity sound from a relatively small (655.5 cm3 [40 in3]) seismic air gun to reduce survival of lake trout embryos. Lake trout embryos at multiple stages of development were exposed to a single discharge of the seismic air gun at two depths (5 and 15 m) and at two distances from the air gun (0.1 and 2.7 m). Control groups for each developmental stage, distance, and depth were treated identically except that the air gun was not discharged. Mortality in lake trout embryos treated at 0.1 m from the air gun was 100% at 74 daily temperature units in degrees Celsius (TU°C) at both depths. Median mortality in lake trout embryos treated at 0.1 m from the air gun at 207 TU°C (93%) and 267 °C (78%) appeared to be higher than that of controls (49% and 48%, respectively) at 15-m depth. Among the four lake trout developmental stages, exposure to the air gun at 0.1 m resulted in acute mortality up to 60% greater than that of controls. Mortality at a distance of 2.7 m did not appear to differ from that of controls at any developmental stage or at either depth. Our results indicate that seismic air guns have potential as an alternative tool for controlling nonnative lake trout, but further investigation is warranted.

  9. Restoration in northern Lake Gehu, a eutrophic lake in China

    Science.gov (United States)

    Wu, Xiaodong; Li, Wenchao; Pan, Jizheng; Ma, Shuzhan; Chen, Bingfa; He, Shangwei

    2017-02-01

    Lake Gehu is a severely eutrophic lake in southeast China. A series of restoration measures have been implemented since 2009 in northern Lake Gehu. This study compared aquatic plants, water quality, sediment, and phytoplankton between restoration and control areas to investigate the effect of restoration measures. The results demonstrated that aquatic macrophyte coverage increased from 0% to 10.6%; mean TP, TN, and CODMn concentrations increased by 50.0%, 42.4%, and 40.8%, respectively, compared with those before the measures were carried out; the mean Secchi depth (SD) increased to 42.5 cm, which is 1.4 times higher than that before restoration; the mean euphotic depth (Zeu) in the summer increased from 91 to 130 cm; the mean chl a concentration decreased from 34.8 to 20.2 μg/L, compared with that before restoration; the Shannon-Wiener index of phytoplankton increased by 28.7%. The mean TP and TN concentrations in sediments decreased by 63.8% and 52.4%, respectively, compared with that before dredging. These results indicate that the restoration in northern Lake Gehu was effective. To complete the transformation from an algae- to a macrophyte-stable state within the region, further measures must be adopted. This restoration of a eutrophic lake can serve as a reference for similar eutrophic lakes.

  10. Morphological variation of siscowet lake trout in Lake Superior

    Science.gov (United States)

    Bronte, C.R.; Moore, S.A.

    2007-01-01

    Historically, Lake Superior has contained many morphologically distinct forms of the lake trout Salvelinus namaycush that have occupied specific depths and locations and spawned at specific times of the year. Today, as was probably the case historically, the siscowet morphotype is the most abundant. Recent interest in harvesting siscowets to extract oil containing omega-3 fatty acids will require additional knowledge of the biology and stock structure of these lightly exploited populations. The objective of this study was to determine whether shape differences exist among siscowet populations across Lake Superior and whether these shape differences can be used to infer stock structure. Morphometric analysis (truss protocol) was used to differentiate among siscowets sampled from 23 locations in Lake Superior. We analyzed 31 distance measurements among 14 anatomical landmarks taken from digital images of fish recorded in the field. Cluster analysis of size-corrected data separated fish into three geographic groups: The Isle Royale, eastern (Michigan), and western regions (Michigan). Finer scales of stock structure were also suggested. Discriminant function analysis demonstrated that head measurements contributed to most of the observed variation. Cross-validation classification rates indicated that 67–71% of individual fish were correctly classified to their region of capture. This is the first study to present shape differences associated with location within a lake trout morphotype in Lake Superior.

  11. Holocene lake deposits of Bosten Lake, southern Xinjiang, China

    Institute of Scientific and Technical Information of China (English)

    B. Wünnemann; CHEN Fahu; F. Riedel; ZHANG Chengjun; S. Mischke; CHEN Guangjie; D. Demske; MING Jin

    2003-01-01

    A 9.25-m-long sediment core from Bosten Lake, Xinjiang, provides detailed information about changes in the water budget and biological acticity over the last 8400 calendar years. The chronology is constructed from six AMS radiocarbon dates on the terrestrial plant remains. Based on analyses of TOC, CO3, detrital compounds and biogenic SiO2, lake level fluctuations and periods of remarkably-negative water budget appeared at 8.4-8.2 cal ka, 7.38-7.25 cal ka, 5.7-5.5 cal ka, 3.7-3.4 cal ka and 3.3-2.9 cal ka, respectively. As they are in-phase with low lake levels at Sumxi Co and Bangong Co in western Tibet Plateau and with paleolakes in Inner Mongolia, a climate-induced change to somewhat drier andwarmer conditions is inferred. A further drop in lake level after 1320 AD of about 200 yr duration may be attributed to a negative water balance prior to the main phase of the Little Ice Age. Deep and stable lake phases of 1500 yr and 1800yr duration at 7.2-5.7 cal ka and 5.5-3.7 cal ka coincide with maximum moisture during the Holocene Megathermal in China. The long term trend towards ariditysince about 4.3 cal ka can clearly be recognised. The reduced water budget of Bosten Lake from 640-1200 AD may be attributed to local effects.

  12. 3D modelling of interaction of strongly nonlinear internal seiches with a concave lake topography and a phenomenon of the "lake monsters".

    Science.gov (United States)

    Terletska, Kateryna; Maderich, Vladimir; Brovchenko, Igor; Jung, Kyung Tae

    2013-04-01

    critical values after which jet sink to maximal depth, then stop and rapidly rising up to surface interacting with thermocline where vortex pair is formed, 4) the just formed vortex pair continue moving in thermocline with a critical speed causing wave wake. This wake is also can be visible on the surface of the lake, 5) the final stage of interaction is the formation of solitons and the second internal mode. The appearance of surface wake in such idealized elongated elliptic-shape lake was the motivation for carrying further modeling of internal seiches in the real lake. This phenomenon can be the explanation of the fact that number of eyewitness around the world claimed to see "lake monsters" moved rapidly and then submerged leaving a wake. Its usually occur in elongated lakes in moderate latitude with a well defined seasonal termocline. Numerical modeling of the interaction of internal seiche with a North end of the Loch Ness confirms possibility of the supercritical internal jet generation and subsequent internal and surface disturbances. We hypotheses that some of eyewitness and legends on the "lake monsters" can be explained by such observations of suddently occurred surface wake behind disturbance generated by focusing flows by bottom topography. [1] Horn DA, Imberger J, Ivey GN.: The degeneration of large-scale interfacial gravity waves in lakes. J. Fluid Mech 434: 181-207, 2001. [2] Maderich V., Brovchenko I., Terletska K., Hutter K.: Numerical simulations of the nonhydrostatic transformation of basin-scale internal gravity waves and wave-enhanced meromixis in lakes. Ch. 4 in Hutter K. (Ed.) Nonlinear internal waves in lakes. Springer. Series: Advances in Geophysical and Environmental Mechanics p. 193-276, 2012. [3] Kanarska Y, Maderich V.: A non-hydrostatic numerical model for calculating free-surface stratified flows. Ocean Dynamics 53: 176-185, 2003.

  13. Stages of Esophageal Cancer

    Science.gov (United States)

    ... stage 0 , abnormal cells are found in the mucosa or submucosa layer of the esophagus wall. These ... found. Stage IA : Cancer has formed in the mucosa or submucosa layer of the esophagus wall. The ...

  14. Stages of Adolescence

    Science.gov (United States)

    ... Español Text Size Email Print Share Stages of Adolescence Page Content Article Body Adolescence, these years from puberty to adulthood, may be roughly divided into three stages: early adolescence, generally ages eleven to fourteen; middle adolescence, ages ...

  15. Cervical Cancer Stage IVB

    Science.gov (United States)

    ... of the body, such as the lymph nodes, lung, liver, intestine, or bone. Stage IVB cervical cancer. Topics/Categories: Anatomy -- Gynecologic Cancer Types -- Cervical Cancer Staging Type: Color, ...

  16. Dynamic Stage Design

    Institute of Scientific and Technical Information of China (English)

    Florian von Hofen[GER

    2013-01-01

    Concepts and methods for dynamic stage designs were introduced ranging from different ifelds of TV live shows, exhibitions and theatre performances, and a special emphasis was put on solution to the theatre stage design.

  17. Ages and Stages: Teen

    Science.gov (United States)

    ... Spread the Word Shop AAP Find a Pediatrician Ages & Stages Prenatal Baby Toddler Preschool Gradeschool Teen Dating & ... Safety School Substance Abuse Young Adult Healthy Children > Ages & Stages > Teen Teen Article Body Adolescence can be ...

  18. Breast cancer staging

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/patientinstructions/000911.htm Breast cancer staging To use the sharing features on this ... Once your health care team knows you have breast cancer , they will do more tests to stage it. ...

  19. The deep-lake deposit in the Upper Triassic Yanchang Formation in Ordos Basin, China and its significance for oil-gas accumulation

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The deep-lake facies of the Yanchang Formation represents a large outflowing lake basin in the Ordos area. Its deposition can be divided into four stages: lake genetic and expanding stage, peak stage, inversion stage and dying stage. All the stages are obviously consistent with the evolution of depositional environment and the paleoclimate in the region. The study indicates that the lake basin has evolution fluctuations from highstand to lowstand for four times in its evolution history, and the deposition center of the lake has not obviously moved, staying along the Huachi-Yijun belt. The deep lake sedimentary system mainly consists of deep water deltas and turbidite fans during the entire evolution course of the lake basin in the Late Triassic. The former mainly developed on the slope of steep shore of the delta in the early period of the deep-water expansion and gradually experienced a big shift from deep-water deltas to shallow-water platform delta. And the latter appeared almost in all the above stages and had two types of turbidite fans, slope-moving turbidite fans and slump turbidite fans. The slope-moving turbidite fans have relatively complete facies belts overlapping one another vertically and consist of the slope channel of inter fans, the turbidite channel, inter turbidite channel and turbidite channel front of middle fans and outer fans (or lakebottom plain). However, the slide-moving turbidity fans are formed in the deep lake with their microfacies difficult to be distinguished, and only the center microfacies and edge microfacies can be determined. The two types of the turbidity fans are similarly distributing in the near-root-slope and far-root-slope regions. The deep-lake deposition governs the distribution of the hydrocarbon and reservoir, while the slope-moving turbidite fans are excellent reservoirs for oil-gas exploration due to their great thickness, widespread distribution and accumulation properties.

  20. Calidad Sanitaria de las Aguas de Playa Jacó: Costa Rica 1986-2008 Sanitary Conditions of Beach Waters in Jacó: Costa Rica 1986-2008

    Directory of Open Access Journals (Sweden)

    Darner Adrián Mora Alvarado

    2009-07-01

    Full Text Available Objetivo: Estudiar la calidad sanitaria de las aguas de playa Jacó, mediante inspecciones sanitarias y muestras realizadas en el período 2002 al 2008, y su comparación con los resultados obtenidos en los períodos 1986-1987 y 1996-2000. Método: Se realizó un análisis de la evolución histórica de la calidad de la playa, en los períodos 1986-1987 y 1996-2000; luego, se analizó en detalle los promedios geométricos, mínimos y máximos anuales de Coliformes fecales/100mL (CF/100mL, en el período 2002-2008. La evaluación de la calidad del agua se hizo con los "Criterios Bacteriológicos Nacionales para Evaluar las Aguas de Mar de Contacto Directo" (natación, en donde el límite para calificar las aguas de mar es de 240CF/100mL; además, se estudiaron las cuatro desembocaduras de aguas superficiales (tres quebradas y el río Copey. Resultados: Se presento un incremento de la contaminación fecal de las aguas de mar en Jacó durante las dos últimas décadas; esta situación se agravó en el año 2008, en donde en al menos dos puntos de muestreo el agua se clasifica como no apta para la natación. Además, se identificaron grande densidades de CF/100mL en las tres quebradas y el río Copey lo cual, unido al uso de tanques sépticos, influye en la calidad sanitaria de la playa. Discusión: El crecimiento urbano y turístico de la zona en forma desordenada ha afectado la calidad sanitaria de la playa, clasificándose en los años 2005 y 2008 como clase E y D, respectivamente; es decir, actualmente esta playa es "no apta para la natación".Objective: To study sanitary conditions of beach waters in Playa Jacó through sanitary inspection and samplings for the period 2002-2008, as compared to results of the periods 1986-1987 and 1996-2000. Method: First, an analysis was performed on the historical evolution of the quality of the beach in the periods 1986- 1987 and 1996-2000; then the annual geometrical average, the minimum and the maximum of

  1. Audubon National Wildlife Refuge, Lake Nettie National Wildlife Refuge, Camp Lake Easement Refuge, Wintering River Easement Refuge, Cottonwood Lake Easement Refuge, Sheyenne Lake Easement Refuge, Lake Otis Easement Refuge : Narrative report : 1970

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Audubon National Wildlife Refuge (including Lake Nettie National Wildlife Refuge, Camp Lake Easement Refuge, Cottonwood Lake...

  2. Aquatic macrophyte richness in Danish lakes in relation to alkalinity, transparency, and lake area

    DEFF Research Database (Denmark)

    Vestergaard, Ole Skafte; Sand-Jensen, Kaj

    2000-01-01

    alkalinity but 12.3 in lakes of high alkalinity due to a greater occurrence of the species-rich group of elodeids. Mean species richness per lake also increased significantly with increasing Secchi depth. No significant relationship between species richness and lake surface area was observed among the entire...... group of lakes or a subset of eutrophic lakes, as the growth of submerged macrophytes in large lakes may be restricted by wave action in shallow water and light restriction in deep water. In contrast, macrophyte species richness increased with lake surface area in transparent lakes, presumably due...

  3. Management recommendations: Sand Lake Complex

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This document is a review of land management practices at the Sand Lake National Wildlife Refuge, by a land use specialist. Recommendations, time frame and...

  4. Big Lake Dam Inspection Report

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This report summarizes an inspection of the Big Lake Dam that was done in September of 1983. The inspection did not reveal any conditions that constitute and...

  5. Folsom Lake 2005 Sedimentation Survey

    Data.gov (United States)

    US Bureau of Reclamation, Department of the Interior — The Bureau of Reclamation (Reclamation) surveyed Folsom Lake in the fall of 2005 via an interagency agreement with the U.S. Army Corps of Engineers (Corps of...

  6. Lakes Ecosystem Services Download Package

    Data.gov (United States)

    U.S. Environmental Protection Agency — This data download package contains Esri 10.0 MXDs, file geodatabases and copy of this FGDC metadata record. The data in this package are used in support of the Lake...

  7. Bear study, Karluk Lake, 1956

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Based on observations, 117 bears were estimated to live in the Karluk Lake area. The estimate was lower than estimates from 1952, and 1954-1955. Annual loss to...

  8. Functional microbiology of soda lakes.

    Science.gov (United States)

    Sorokin, Dimitry Y; Banciu, Horia L; Muyzer, Gerard

    2015-06-01

    Soda lakes represent unique permanently haloalkaline system. Despite the harsh conditions, they are inhabited by abundant, mostly prokaryotic, microbial communities. This review summarizes results of studies of main functional groups of the soda lake prokaryotes responsible for carbon, nitrogen and sulfur cycling, including oxygenic and anoxygenic phototrophs, aerobic chemolithotrophs, fermenting and respiring anaerobes. The main conclusion from this work is that the soda lakes are very different from other high-salt systems in respect to microbial richness and activity. The reason for this difference is determined by the major physico-chemical features of two dominant salts - NaCl in neutral saline systems and sodium carbonates in soda lakes, that are influencing the amount of energy required for osmotic adaptation.

  9. Lake Ladora sampling plan, 1993

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Task plan from the U.S. Geological Survey for sampling Lake Ladora on the Rocky Mountain National Wildlife Refuge. During the review of the FY93 Surface-Water...

  10. Great Lakes Environmental Research Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — NOAA-GLERL and its partners conduct innovative research on the dynamic environments and ecosystems of the Great Lakes and coastal regions to provide information for...

  11. Management recommendations: Benton Lake Complex

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This document is a review of land management practices at the Benton Lake Complex, by a land use specialist. Recommendations, time frame and additional comments are...

  12. Great Lakes Initiative (GLI) Clearinghouse

    Data.gov (United States)

    U.S. Environmental Protection Agency — The Great Lakes Initiative Toxicity Data Clearinghouse is a central location for information on criteria, toxicity data, exposure parameters and other supporting...

  13. Abundancias poblacionales, crecimiento y mortalidad natural de la macroinfauna de crustáceos en dos tipos morfodinámicos de playas arenosas del sur de Chile Population abundances, growth and natural mortality of the crustacean macroinfauna at two sand beach morphodynamic types in southern Chile

    Directory of Open Access Journals (Sweden)

    HERALDO CONTRERAS

    2003-12-01

    Full Text Available Se realizaron muestreos mensuales durante 1994-1996 en una playa arenosa intermedia y en una playa disipativa del sur de Chile (Calfuco y Mehuín, respectivamente; ca. 39º S, para evaluar las predicciones de la hipótesis de exclusión por la resaca sobre las abundancias poblacionales e historia de vida de la macroinfauna de crustáceos que habita en el intermareal de esas playas. Se hipotetiza que solo las especies realmente intermareales (i.e., directamente afectadas por la resaca son afectadas por diferencias en los tipos morfodinámicos de playas. Esas especies fueron los isópodos cirolánidos Excirolana braziliensis y Excirolana hirsuticauda y el cangrejo anomuro Emerita analoga. Por otra parte, el anfípodo Orchestoidea tuberculata (mayoritariamente supralitoral no debiera ser afectado por diferencias en tipos morfodinámicos de playas. Las abundancias poblacionales totales de O. tuberculata y E. analoga fueron significativamente más altas en la playa intermedia de Calfuco, las de E. braziliensis y E. hirsuticauda en la playa disipativa de Mehuín. Mientras que las abundancias de las hembras ovígeras de O. tuberculata y E. analoga fueron más altas en Calfuco, las de las hembras ovígeras de E. braziliensis y E. hirsuticauda no difirieron entre playas. Los juveniles de O. tuberculata fueron más abundantes en Calfuco, mientras que los de las otras especies en Calfuco. Los máximos en los períodos reproductivos de anfípodos e isópodos ocurrieron durante los mismos meses de primavera-verano en ambas playas. El período reproductivo de E. analoga también ocurrió durante primavera-verano, pero los máximos de abundancia ocurrieron en meses diferentes. Mientras que las máximas abundancias de los juveniles de O. tuberculata ocurrieron en períodos similares, las de los juveniles de Excirolana braziliensis y E. hirsuticauda ocurrieron más tarde en Mehuín. Los juveniles de E. analoga tuvieron abundancias muy bajas durante el primer per

  14. Cervical Cancer Stage IIIB

    Science.gov (United States)

    ... hyphen, e.g. -historical Searches are case-insensitive Cervical Cancer Stage IIIB Add to My Pictures View /Download : ... 1425x1326 View Download Large: 2850x2651 View Download Title: Cervical Cancer Stage IIIB Description: Stage IIIB cervical cancer; drawing ...

  15. Cervical Cancer Stage IB

    Science.gov (United States)

    ... hyphen, e.g. -historical Searches are case-insensitive Cervical Cancer Stage IB Add to My Pictures View /Download : ... 1613x1200 View Download Large: 3225x2400 View Download Title: Cervical Cancer Stage IB Description: Stage IB1 and IB2 cervical ...

  16. Cervical Cancer Stage IIIA

    Science.gov (United States)

    ... hyphen, e.g. -historical Searches are case-insensitive Cervical Cancer Stage IIIA Add to My Pictures View /Download : ... 1275x1275 View Download Large: 2550x2550 View Download Title: Cervical Cancer Stage IIIA Description: Stage IIIA cervical cancer; drawing ...

  17. Cervical Cancer Stage IA

    Science.gov (United States)

    ... hyphen, e.g. -historical Searches are case-insensitive Cervical Cancer Stage IA Add to My Pictures View /Download : ... 1500x1200 View Download Large: 3000x2400 View Download Title: Cervical Cancer Stage IA Description: Stage IA1 and IA2 cervical ...

  18. Beyond Erikson's Eight Stages.

    Science.gov (United States)

    Whitney, Ruth

    1979-01-01

    Erik Erikson has described eight stages of the healthy personality. This essay offers a revised version of the eight stages. Although most individuals develop through the eight stages, each is personally unique because patterns of fluctuation between safety and growth differ from one individual to another. (Author)

  19. Ovarian Cancer Stage II

    Science.gov (United States)

    ... hyphen, e.g. -historical Searches are case-insensitive Ovarian Cancer Stage II Add to My Pictures View /Download : ... 1650x675 View Download Large: 3300x1350 View Download Title: Ovarian Cancer Stage II Description: Three-panel drawing of stage ...

  20. Ovarian Cancer Stage IIIC

    Science.gov (United States)

    ... hyphen, e.g. -historical Searches are case-insensitive Ovarian Cancer Stage IIIC Add to My Pictures View /Download : ... 1530x1350 View Download Large: 3060x2700 View Download Title: Ovarian Cancer Stage IIIC Description: Drawing of stage IIIC shows ...