Minerogenetic mechanisms in the Irazú caves The transport of ions and chemical compounds in the caves and the consequent mineral precipitation can occur from mineralized solutions and this may happen both in subaerial or subaqueous settings. Each of the transport mechanisms can trigger different minerogenetic processes. Mineralized solutions plays a very important role in the transportation of chemical elements and compounds into the caves. Water geochemistry analyses indicate considerable concentrations of sulfates in the main crater lake (Supplementary Table 1), and infiltration water analyses indicated the presence of Se, Fe, Al, Ca, Mg, Na, Mn, K, Zn, Ni, and Co ions (Fig. 3C). Selenium is the only element that is not reflected in the elemental composition of the reported minerals. Enrichment in selenium (993.1 mg/l) might be associated with the input of geothermal waters (Floor & Román-Ross, 2012). Iron concentration is 440.2 ppm in the infiltration waters and is present in the chemical composition of 20 minerals, followed by calcium present in 14 different minerals. Stalactites and stalagmites (usually green to blue in color) are associated with dissolution-precipitation processes of Fe-sulfate-rich infiltration waters. They are found in “Sala de los Cristales Verdes”, formed by iron hydrated
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These estimations were either based on long-time observation or punctual measurements. Since the lake is a very dynamic system, heat fluxes could vary significantly from one day to another, which was not accounted for in the previous studies. Furthermore, for a better understanding of lake dynamics, it is important to consider more precise and accurate meteorological data. In this study, we present for the first time continuous physical data of the crater lake (temperature, depth) as well as meteorological parameters (precipitation, wind velocity, solar radiation) measured by a nearby meteorological station (Figure 2) and two data- loggers. Using a mass and heat budget model constrained with these data, a new estimation of heat and mass fluxes is proposed. This kind of continuous monitoring could help to understand the dynamics of this complex lake-springs- fumaroles system and could provide an efficient way of monitoring the volcanic activity.
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At the Cerro Chato crater lake, thermocIine fluctuations have been observed at a depth between five and eight meters (Umaña & Jiménez 1995) suggesting the formation of internal seiches. The thermocIíne' s fluctuatíon and depth range coincides with the decrease in species diversity and evenness (six meters depth, Fig. 4). Those oscillations produce changes in temperature and other physical chemical parameters affecting organisms in several manners. Umaña y Jiménez ( 1995) sug gest the intrusion of a more dense and highly oxigenated runoff water into the lake, localized at six meters depth. It is possible that this layer
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The dominance of P. inconspicuum has been a constant feature of Botos Lake throughout the study and even before (Hargraves & Víquez 1981). This is a common species in many other lakes that are not as acid as Botos (Haberyan et al. 1995). An examination of this and other unpublished data show that the species’ abun- dance increases with altitude. This increase with altitude is more likely influenced by a decrease that has been documented in conduc- tivity and hardness with altitude of the lake. Reynolds (1984) classifies the genus Peridinium as a late invader in the seasonal succession in temperate lakes, becoming abundant by late summer when stratification is stronger and nutrient availability is lowest due to uptake by algae during summer. It is also referred to as the dominant tropical dinoflagellate. The stability of environmental conditions in Botos Lake, which does not stratify, but has a mixing depth well within the euphotic zone due to its shal- lowness and high water transparency, seems to favor these slow-growing species, which has also been classified as a K-strategist (Reynolds 1984). Sommer (1989) indicates that Peridinium is usually limited by phosphorus, and includes it with the species that dominate at the climax of phytoplankton succession in lakes. The abun- dance of phosphorus relative to nitrogen also
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Estas redes se han instalado por equipos de diversos países formando el grupo de trabajo sobre permafrost Antártico y Subantártico (ANTPAS) de la IPA (Vieira et al., 2010). Uno de estos equipos pertenece a España y está integrado por investigadores de la Universidad de Alcalá, con quienes colaboran investigadores de Portugal, Rusia, Suiza, y República Checa. Este equipo, ha instalado diversas estaciones CALM y TSP en las Islas Livingston y Decepción del Archipiélago de las Shetland del Sur (ej., Correia et al., 2012; de Pablo et al., 2013, 2014; Goyanes et al., 2014; Ramos et al., 2017; Oliva et al., 2017). La más importante de ellas se encuentra en la isla Decepción (Figura 2), en la zona de Cráter Lake, a unos 85 m s.n.m., y en las proximidades de la Base Antártica Española Gabriel de Castilla (Tomé et al., 2009; Ramos et al., 2010). Aunque la estación CALM para el estudio de la descongelación de la capa activa fue instalada por estos investigadores en el año 2006, no fue hasta el año 2008, cuando bajo la iniciativa internacional del Año Polar Internacional 2008-2009, se realizaron las perforaciones para la instalación de 3 estaciones TSP (denominadas STS_1, STS_2 y STS_3) que permitieran estudiar la evolución de la temperatura del terreno y su respuesta a las condiciones climáticas (Ramos et al., 2017).
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Samples for chlorophyll and phytoplankton were taken using a Niskin water sampler (Gene ral Oceanics) fmm selected depths in May and June 1992. Ch1orophyll was measured with the trichromatic formulas by SCORIUNESCO (Strickland and Parsons 1972). Phytoplankton samples consisted of 140 mI of whole lake wa ter, flXed with acetic Lugol's solution. Samples were allowed to for two days and later we re coneentrated by siphoning off the supernatant and by centrifugation (Umaña 1985). Counts were made with a Palmer-Maloney counting chamber with a 40x objective. A maximum Of 100 individuals of the most abundant species were counted (ef. Lewis 1978). A total of 5 tran sects in ¡he mid portion of the chamber were scanned for the most rare species. Zooplank:ton vertical hauls were performed on 8 April and 28 May, 1992 using a weighted 80 � mesh size Wisconsin plankton net with opening diameter of 11.7 cm from the depth of 18 m.
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La cantidad de datos que se generan, tanto por los mensajes emitidos por los navíos como por los generados a través de redes sociales o Internet, especialmente en buques dedicados al transporte de pasajeros, aumenta cada día. El gran aumento en la cantidad de datos obtenidos ha puesto en jaque a las arquitecturas tradicionales de almacenamiento de información, oca- sionando graves problemas derivados principalmente de la escalabilidad. Gracias a los grandes avances que se han producido en el área de almacenamiento, asociados a la creación de nuevas arquitecturas Big Data, es posible encontrar solución a estos problemas de escalabilidad. En la actualidad una de las arquitecturas desarrolladas más novedosa y que más se está utilizando ante problemas de escalabilidad es el Data Lake. Esta arquitectura surge como un repositorio capaz de almacenar cualquier tipo de dato, estructurado, semi estructurado y no estructurado, sin ningún tipo de pre procesamiento ni esquema para su posterior análisis. La posibilidad de almacenar en bruto los datos, cargándose directamente desde las fuentes originales, permite ges- tionar información cuya utilidad puede ser desconocida en la actualidad, pero que en un futuro puede ser de gran interés, siendo esta una de las mayores ventajas de este tipo de arquitecturas.
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The qualitative food composition indicated that food item from detritus; plant and animal sources are important, their RI values were higher than 5 %. It can therefore be inferred that S. membranaceus is omnivorous or eury- phagous and occupy the third link of the food chain by feeding on phytoplankton and plant materials (primary producers); and makes the resultant energy available to predatory species within the water body. Omnivory or eury- phagy is a characteristic feature of ubiquitous fishes (Lowe-McConnell 1975, Welcomme 1979, 1985) and explains S. membranaceus’s wide distribution, a phenomenon reported also for other mochokid catfishes (Olatunde 1989, Owolabi and Omotosho 1999, Araoye and Jeje 1999). Therefore the overwhelming presence of S. membranaceus in Jebba lake appears to
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Para evaluar la prominencia de la marca en la mente de los consumidores se evaluó el conocimiento de marca Inca Lake que tenían los clientes, la mayoría de los encuestados señala que la marca no le es “ni conocida, ni desconocida”, es decir la profundidad de la marca es regular ya que la empresa no es tan fácil de recordar y reconocer, por otro lado, las otras dos respuestas que predominan son el “muy poco conocida” y “poco conocida”. Para medir la amplitud de la marca, es decir la variedad de situaciones de compra de tours, se halló que los turistas nacionales y extranjeros optan por un tour, mientras que otros con cifras un poco inferiores optan por tomar 2, 3, y 4 servicios con la misma agencia, algunos de ellos componen diferentes tours en la región de Puno y algunos otros en regiones aledañas de sur del Perú. Cabe tener en cuenta que no se maneja una amplitud adecuada ya que los consumidores solo asocian a la empresa con tours en la ciudad de Puno limitando su amplitud a los otros destinos.
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A solution was suggested by CAMP- BELL (1968) and BOWLER (1968) and, it transpired, and incidentally, by WOODS (1862, pp. 27-28). Working in the South East District of South Australia, Woods noted that flotsam was carried by wind-driven waves to the lee shores of lakes. Campbell made similar observations in the region around her childhood home, near Naraco- orte, also in the South East. When the playa carried water the salt crust was dissolved. Thus the underlying sediment could be drifted by waves to the lee shore. Bowler’s discovery of gravel in lunettes also pointed to wave transport. The sediments deposited on the lee shore formed beaches from which the wind winnowed material of suitable size and carried it a short distance into vegetated areas where it was trapped and built up into immobile dunes or lunettes. Thus lunettes were interpreted as analogous to coastal foredunes. In this respect it is salutary to re- call that when approaching the salina in July 1840, Eyre “found Lake Torrens completely girded by a steep sandy ridge, exactly like the sandy ridges bounding the sea shore…” (EYRE, 1845, I, p. 58)!
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Within the framework of the LIFE project "Restoration of the Bittern habitat in two coastal lakes in Latvia", there have been organized voluntary works for habitats management, 7 schools excursions, 17 educational events for students, as well as 3 educational meetings with local governments and 2 with reed mowers, the film "T wo lakes - one Bittern"as well as a traveling open-air exhibition and other informative materials about the lake and its inhabitants.
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The zooplankton showed a poor species diversity, with only seven species, all of which have small body size. The lack of big zooplank ters has been described as typical of many tropi cal lakes (Fernando 1980). One possible reason for this faet is a strong predation pressure all year round, exerted mainly by vertebrate predators. Fishes are mainly visual predators (Sommer 1989) preying preferrably upon the large bodied Cladocerans and Copepods. This may be the case in Lake Bonilla, where a rich ichthyofauna seems to be present including small characids and poe cilids that were observed close to the shore. High temperatures have also been proposed as a rea son for small bodied zooplankters in tropical lakes (Fernando 1980). There seems to be a typi cal vertical migration of the zooplankton since vertical and surface horizontal tows yielded dif ferent catch compositions. Ceriod aphnia comuta, Bosmina hogmanl'1i, and Microcyclops sp. were the species which showed a deeper dis tribution during the day. Haberyan et al. (1995) alsó report the presence of Tropocyclops prasi nus in lake Bonilla
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Fieldwork was carried out at Zumpango Lake on August 2006. Seven sampling points were selected. Six of them (1-5, 7) were distributed surrounding the lake for covering the input of water in it and the last one (6) was located at the deepest zone of the lake, close to the centre of the water body. Each sampling point was geo-referred with a GPS (Garmin, Ltd) and optical measurements such as Secchi transparency and hyperspectral reflectance were also performed. Afterwards, hyperspectral data were analyzed through a derivative method. Water samples were collected at each sampling site at the surface and at 0.5 m depth for laboratory analysis of chlorophyll concentration using fluo- rometric methods.
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Operators Association (ALTOA) based at Leh. Tsomoriri, which is major attraction for tourists, has experienced rapid development of tourism ever since it was first opened up to outside visitors in 1994. At present about 20,000 tourists, mainly from European countries and other parts of India, visit Lake Tsomoriri each year during the short summer season between June to September. The construction of a metalled road which
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ordinance. It started the activity for conserving wetlands ecosystem in the lakeshore of Lake Biwa. In1993, it was registered as a Ramsar site. Lake Biwa is important as aquatic resources for 15 million people living in the lower basin of the Lake. The 20th anniversary of Lake Biwa Ramsar Site should be celebrated not only by Shiga, but also by many people of Lake Biwa & Yodo river basin(Figure 2) including Osaka & Kyoto City.
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Lake between March 2005 and August 2006. Samples were collected from the littoral, sub- littoral and pelagic stations. Temperature, pH, Dissolved Oxygen (DO 2 ), percentage satura- tion of oxygen (% O 2 ), conductivity and Total Dissolved Solids (TDS) were measured in situ using portable Hanna field metres. Transparen- cy was determined using secchi disc. Biologi- cal Oxygen Demand (BOD) was determined according to the methods of APHA (1992). At each station, zooplankton was collected by three horizontal tows over a distance of 100m using 0.5m diameter (45μm mesh size) net. The three samples were pooled and preserved in 4% formalin. The following taxonomic keys were used in zooplankton identification: Rotifera (Koste 1978, Segers 1993, Segers, et al. 1993), Cladoceran (Jeje & Fernando 1986, Korovchinsky 1992), Copepoda (Jeje 1988, Williamson 1991, Ueda & Reid 2003). Quantitative estimate of zooplankton groups was done under the light microscope at 100x magnification. Five sub-samples of 15ml each were usually counted from each collected sample and the mean density used to compute abundance. All the crustaceans in the sample were counted as recommended by Downing & Rigler (1984). At least 100 individuals of rotifers and developmental stages were counted in order to reduce the coefficient of variation to a maximum of 10%.
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The Carancas impact crater is roughly circular in shape and has an average diameter of 14.2 ± 0.23 m, measured from rim crest to rim crest in 10° radial steps (Figs. 1 and 2). Data were taken 3.5 months after the event and give slightly larger values than measurements carried out shortly after the impact event (13.3–13.8 m, Macedo and Macharé 2007; 13.5 m; Núñez del Prado et a. 2008; Tancredi et al. 2008). These differences may indicate erosion and degradation of the crater rim. The crater formed at the edge of a ~1 m high creek bank. The creek bed is a periodic watercourse that was dry during the impact but contained subsurface water. The embankment influenced the crater morphology: (i) The crater cavity has higher and steeper slopes at the terrace (Figs. 1e, 2b, 3a). (ii) The steep slopes induced slumping of meter-sized soil blocks in the north and west (Figs. 1f, 2a). (iii) The center of the small crater pond is offset towards the creek bed (SE) with respect to the crater center (Fig. 2a). (iv) The crater rim on the terrace is higher than average, although scattering is large and slumping strongly modifies the height of the rim (Fig. 3b).
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We consider maar desiccation in the Valle de Santiago area as a consequence of drawdown in the Valle de Santiago – Salamanca aquifer (Aranda-Gómez et al., 2009). Therefore, subsidence at the bottom of the crater could be, in part, associated with this phenomenon as significant compaction of the lake beds probably occurred. A comparison between the mean subsidence velocity in the Salamanca fault (6 cm/year) and the collapse structure inside the crater (50 cm/year; assuming that the at least 10 m high topographic scarp was formed in the past 20 years) suggests that an additional process may be operating in the crater. Presence of a significant amount of the water-soluble salts halite, sylvite, trona, and other Na carbonates was established by us using XRD. In a simple test to estimate the amount of soluble minerals in a small lake sediment sample, collected near the depocenter, 33 wt% of the previously dried sample was easily dissolved in distilled water at room temperature. Thus, the remarkable collapse features observed at the bottom of the crater may have been formed in a similar way to the sinkholes studied by Closson (2004) and Closson et al. (2005) around the Dead Sea. Closson (op. cit) first proposed a model where the flow of unsaturated groundwater dissolved concealed evaporite layers, which caused the formation of underground cavities that later collapsed, producing sinkholes on the surface. Although there are no reports of formation of sinkholes at Rincón de Parangueo, we envision a gradual removal of the soluble salts, and an increase of the height difference between the depocenter of lake and its shore creating the potential for continuous slow movement landslides. The Rincón de Parangueo maar is a partly closed system. Rainwater that falls inside the closed basin of crater is now feeding an ephemeral playa lake. Freshwater rain can dissolve the soluble salts in the lake sediments. Part of the newly formed brine infiltrates the ground and the rest is lost through evaporation with the consequent re-precipitation of part of the dissolved salts. We hypothesize that underground water flow is now moving solutes into the regional aquifer. Residents of the area have noticed an increase in the salinity of the water in their wells in recent years.
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The late Neoproterozoic Acraman impact structure occurs mostly in felsic volcanic rocks (Mesoproterozoic Gawler Range Volcanics) in the Gawler Ranges, South Australia, and strongly influences the topography of the region. The structure is expressed topographically by three main features: a near-circular, 30 km diameter low-lying area (Acraman Depression) that includes the eccentrically placed Lake Acraman playa; a partly fault-controlled arcuate valley (Yardea Corridor) at 85–90 km diameter; and arcuate features at 150 km diameter that are visible on satellite images. Geological and geomorphological observations and apatite fission-track data indicate that Acraman is eroded several kilometres below the crater floor, with the structure originally comprising a transient cavity about 40 km in diameter and a final structural rim 85–90 km in diameter. Ejecta of shock- deformed fragments of felsic volcanic rock up to 20 cm across derived from the Acraman impact form an extensive horizon ≤40 cm thick in Ediacaran (about 580 Ma) shale in the Adelaide Geosyncline 240–370 km to the east of the impact site. A correlative band ≤7 mm thick of sand-sized ejecta occurs in mudstone in the Officer Basin up to 540 km to the northwest of Acraman. The dimensions of the impact structure and the geochemistry of the ejecta horizon imply that the bolide was a chondritic asteroid >4 km in diameter. Acraman ranks among the largest 4% of known terrestrial impact structures, and the impact would have severely perturbed the Ediacaran environment.
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Cuando se habla de su utilidad un Data Lake permite la ingesta de datos de diferentes fuentes: redes sociales, internet de las cosas, base de datos relacional, datawarehouse tradicional, dispositivos móviles, registros de llamadas telefónicas, logs de servidor, etc, convirtiendo a un Data Lake en un repositorio que almacena toda la información de una organización, esto lo ratifica (Khine & Zhao, 2017). Un Data Lake puede ser utilizado para realizar un análisis dinámico de datos, que genere un nuevo conocimiento que aporte a la toma de decisiones en la organización, también puede ser utilizado como fuente de datos para un Datawarehouse tradicional, como soporte para otras aplicaciones, para la explotación de datos en línea, entre otros, esto lo ratifican (SQL Chick, 2016) (Capgemini, 2017) (Alserafi, 2016) (Management Solutions, 2015).
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