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Sample records for plata estuary main

  1. On the path of plumes of the Río De La Plata Estuary main tributaries and their mixing scales

    Directory of Open Access Journals (Sweden)

    Claudia G Simionato

    2009-12-01

    Full Text Available With a length of 300 km and a width that narrows from 220 km at its mouth to 40 km at its upper end, the Río de la Plata is one of the largest estuaries of the world. Its three main tributaries -contributing to a total mean runoff of 22,000 m³ s-1- have different properties and are object of diverse environmental impact due to dissimilar development conditions on their shores. The knowledge of the paths of the plumes of those tributaries along the estuary and their mixing scales is necessary for management purposes. In this paper, advection-diffusion equations for passive tracers are coupled to the three-dimensional Hamburg Shelf Ocean Model and validated by means of a case study. Then, simulations in which each tributary is characterized by a different dye tracer are done for scenarios resulting of the combination of diverse characteristic atmospheric forcing and runoff conditions. The impact of bathymetry and Earth's rotation on plumes paths and mixing is also evaluated. Results indicate that, for mean to low discharge conditions, the path of the waters of the tributaries is in the form of two main plumes. The different water speeds of both tributaries, the presence of a bend immediately after their confluence and the varying geometry and bathymetry of the estuary favor a rapid mixing between the Uruguay and Paraná Guazú-Bravo waters, which then flow along the northern portion of the upper estuary channel. The Paraná de las Palmas waters, instead, occupy the southern shallow region of Playa Honda in the upper estuary and then flow following the southern coast. Downstream Colonia, at the intermediate estuary, the occurrence of another large bend and a change in bathymetric features force the flow to concentrate in the central part of the estuary and favor further mixing between the plumes. For high discharge conditions the northern part of the upper estuary is divided into two regions, one with a larger concentration of Uruguay waters

  2. Penobscot Estuary (Maine) Monitoring

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    National Oceanic and Atmospheric Administration, Department of Commerce — NOAA's NEFSC collects fisheries data from the Penobscot Estuary using several types of fishing gear. The data is used to determine species presence, relative...

  3. Microplastics in gut contents of coastal freshwater fish from Río de la Plata estuary.

    Science.gov (United States)

    Pazos, Rocío S; Maiztegui, Tomás; Colautti, Darío C; Paracampo, Ariel H; Gómez, Nora

    2017-09-15

    The presence of microplastics (MPs) in gut contents of coastal freshwater fish of the Rio de la Plata estuary was studied. Samples were taken in six sites where 87 fish belonging to 11 species and four feeding habits were captured. Presence of MPs was verified in the 100% of fish. The fibres represented the 96% of MPs found. The number of MPs in gut contents was significantly higher close to sewage discharge. There was not found relationship between number of MPs and fish length, weight or feeding habit. The spatial differences in mean number of MPs in fish observed in this study, suggest that environmental availability of MPs could be of great importance to explain the differences found among sampling sites analysed. This work represents the first study about the interaction between MPs and aquatic organisms in this important estuarine ecosystem of South America. Copyright © 2017 Elsevier Ltd. All rights reserved.

  4. Seasonal composition, abundance and biomass of the subestuarine fish assemblage in Solís Chico (Río de la Plata estuary, Uruguay).

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    Plavan, A Acuña; Gurdek, R; Muñoz, N; Gutierrez, J M; Spósito, M; Correa, P; Caride, A

    2017-01-01

    The large estuaries can present long narrow branches called subestuaries or tidal creeks. These types of subsystems are distributed along the Uruguayan coast of the Río de la Plata estuary and are very important as nursery and refuge areas for fish. For the first time, the seasonal composition and abundance of the fish community of the Solís Chico subestuary was studied by using beach and gill nets. Fourteen species, mainly euryhaline (86%) presented a significant representation of juvenile stages. The fish community was dominated by Odontesthes argentinensis, Platanichthys platana, Mugil liza, Brevoortia aurea, Micropogonias furnieri and Paralichthys orbignyanus, similar to adjacent subestuaries. While Micropogonias furnieri and B. aurea were the most abundant species, some other species were rarely caught. A seasonal variation of the fish assemblage abundance was detected, with higher values in autumn showing a positive correlation with temperature. Species that complete their life cycle in the Río de la Plata estuary, some of which are relevant to fisheries (64% of the analyzed species) were captured in the Solís Chico subestuary. The importance of this environment as a transitional system for some estuarine fish species is advised.

  5. 21Pb dating of sediments in a heavily contaminated drainage channel to the La Plata estuary in Buenos Aires, Argentina

    International Nuclear Information System (INIS)

    Di Gregorio, D.E.; Fernandez Niello, J.O.; Huck, H.; Somacal, H.; Curutchet, G.

    2007-01-01

    Concentrations of 21 Pb and 137 Cs in sediment samples collected from two cores at a drainage channel to the La Plata river estuary in Buenos Aires, Argentina, were measured using ultralow-background detection systems. The 21 Pb data were used to determine the rate of sediment accumulation of the sites. These results were correlated with some heavy metal (chromium and lead) concentrations of the samples in an attempt to characterize the historical input of contaminants due to the industrial development, which has taken place in this area over the last century. The 137 Cs measurements demonstrate that cesium dating is not adequate in regions of the southern hemisphere

  6. The Estuary Book: A Guide to Promoting Understanding and Regional Management of Maine's Estuaries and Embayments.

    Science.gov (United States)

    Ruffing, Jenny

    The objective of this document is to provide information about estuaries, the impact of uses on the environmental health of an estuary, and what communities and concerned individuals can do to manage and protect their local estuarine resources successfully. Much of the information presented here pertains to other embayments along the Maine coast…

  7. Tidal variations of flow convergence, shear, and stratification at the Rio de la Plata estuary turbidity front

    Science.gov (United States)

    FramiñAn, Mariana B.; Valle-Levinson, Arnoldo; Sepúlveda, HéCtor H.; Brown, Otis B.

    2008-08-01

    Intratidal variability of density and velocity fields is investigated at the turbidity front of the Río de la Plata Estuary, South America. Current velocity and temperature-salinity profiles collected in August 1999 along a repeated transect crossing the front are analyzed. Horizontal and vertical gradients, stability of the front, convergence zones, and transverse flow associated to the frontal boundary are described. Strong horizontal convergence of the across-front velocity and build up of along-front velocity shear were observed at the front. In the proximity of the front, enhanced transverse (or along-front) flow created jet-like structures at the surface and near the bottom flowing in opposite directions. These structures persisted throughout the tidal cycle and were advected upstream (downstream) by the flood (ebb) current through a distance of ˜10 km. During peak flood, the upper layer flow reversed from its predominant downstream direction and upstreamflow occupied the entire water column; outside the peak flood, two-layer estuarine circulation dominated. Changes in density field were observed in response to tidal straining, tidal advection, and wind-induced mixing, but stratification remained throughout the tidal cycle. This work demonstrates the large spatial variability of the velocity field at the turbidity front; it provides evidence of enhanced transverse circulation along the frontal boundary; and reveals the importance of advective and frictional intratidal processes in the dynamics of the central part of the estuary.

  8. Occurrence of Toxic Cyanobacterial Blooms in Rio de la Plata Estuary, Argentina: Field Study and Data Analysis

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    Giannuzzi, L.; Carvajal, G.; Corradini, M. G.; Araujo Andrade, C.; Echenique, R.; Andrinolo, D.

    2012-01-01

    Water samples were collected during 3 years (2004–2007) at three sampling sites in the Rio de la Plata estuary. Thirteen biological, physical, and chemical parameters were determined on the water samples. The presence of microcystin-LR in the reservoir samples, and also in domestic water samples, was confirmed and quantified. Microcystin-LR concentration ranged between 0.02 and 8.6 μg.L−1. Principal components analysis was used to identify the factors promoting cyanobacteria growth. The proliferation of cyanobacteria was accompanied by the presence of high total and fecal coliforms bacteria (>1500 MNP/100 mL), temperature ≥25°C, and total phosphorus content ≥1.24 mg·L−1. The observed fluctuating patterns of Microcystis aeruginosa, total coliforms, and Microcystin-LR were also described by probabilistic models based on the log-normal and extreme value distributions. The sampling sites were compared in terms of the distribution parameters and the probability of observing high concentrations for Microcystis aeruginosa, total coliforms, and microcystin-LR concentration. PMID:22523486

  9. Oil spill in the Rio de la Plata estuary, Argentina: 2-hydrocarbon disappearance rates in sediments and soils

    International Nuclear Information System (INIS)

    Colombo, J.C.; Barreda, A.; Bilos, C.; Cappelletti, N.; Migoya, M.C.; Skorupka, C.

    2005-01-01

    The 6-month assessment of the oil spill impact in the Rio de la Plata described in the preceding paper [Colombo, J.C., Barreda, A., Bilos, C., Cappelletti, N., Demichelis, S., Lombardi, P., Migoya, M.C., Skorupka, C., Suarez, G., 2004. Oil spill in the Rio de la Plata estuary, Argentina: 1 - biogeochemical assessment of waters, sediments, soils and biota. Environmental Pollution] was followed by a 13- and 42-month campaigns to evaluate the progress of hydrocarbon decay. Average sediment hydrocarbon concentrations in each sampling include high variability (85-260%) due to contrasting site conditions, but reflect a significant overall decrease after 3 years of the spill: 17 ± 27, 18 ± 39 to 0.54 ± 1.4 μg g -1 for aliphatics; 0.44 ± 0.49, 0.99 ± 1.6 to 0.04 ± 0.03 μg g -1 for aromatics at 6, 13 and 42 months, respectively. Average soil hydrocarbon levels are 100-1000 times higher and less variable (61-169%) than sediment values, but display a clear attenuation: 3678 ± 2369, 1880 ± 1141 to 6.0 ± 10 μg g -1 for aliphatics and 38 ± 26, 49 ± 32 to 0.06 ± 0.04 μg g -1 for aromatics. Hydrocarbon concentrations modeled to first-order rate equations yield average rate constants of total loss (biotic + abiotic) twice as higher in soils (k = 0.18-0.19 month -1 ) relative to sediments (0.08-0.10 month -1 ). Individual aliphatic rate constants decrease with increasing molecular weight from 0.21 ± 0.07 month -1 for isoprenoids and -1 for >n-C27, similar to hopanes (0.10 ± 0.05 month -1 ). Aromatics disappearance rates were more homogeneous with higher values for methylated relative to unsubstituted species (0.17 ± 0.05 vs. 0.12 ± 0.05 months -1 ). Continued hydrocarbon inputs, either from biogenic (algal n-C15,17; vascular plant n-C27,29) or combustion related sources (fluoranthene and pyrene), appear to contribute to reduced disappearance rate. According to the different loss rates, hydrocarbons showed clear compositional changes from 6-13 to 42 months

  10. Environmental modulation of the plankton community composition and size-structure along the eutrophic intertidal coast of the Río de la Plata estuary, Argentina

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    Maximiliano D. Garcia

    2014-05-01

    Full Text Available In this study we investigated the spatial distribution of the plankton community, bacterio-, phyto- and zooplankton, in relation with environmental conditions along the intertidal coast of the Río de la Plata estuary, Argentina. Plankton was analyzed in terms of species composition, abundance, biomass (carbon content and size-structure. We aim to evaluate the potential effects of anthropogenic impacts (e.g., nutrient enrichment and physicochemical gradients alongshore (e.g., salinity, turbidity on the composition and functioning of the plankton. We asked whether the natural structuring of the plankton by salinity and turbidity, known to be true of estuaries, is modified by eutrophication along the studied shoreline. We found that the density and biomass of bacteria and phytoplankton were strikingly enhanced by high eutrophication levels along the intertidal southwest coast of the Río de la Plata estuary. We also found that the highest zooplankton density in the most polluted area but the biomass showed a different distribution pattern. Nevertheless, when zooplankton was analyzed by means of its size fraction, we accordingly found that the microzooplankton biomass was positively associated with smaller-size phytoplankton groups and the most polluted study sites. Copepods were the major taxonomic groups that best represented the mesozooplankton biomass. We therefore expected that its distribution was modulated by the presence of its food items (i.e., large cells which, in turn, were more abundant in the middle-outer zone. In contrast, we found that the highest biomass of copepods occurred at the innermost site of the estuary and we found no significant association with other planktonic groups. Overall, this study highlights the noteworthy impacts of human activities modifying the functioning of this coastal ecosystem. The differences found in the taxonomic composition and size structure of the planktonic community assemblage between the most

  11. Long term fish assemblages as units of management in a temperate estuary (Rio de La Plata - SW Atlantic Ocean

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    María Inés Lorenzo

    2011-03-01

    Full Text Available Demersal fish assemblages from trawl surveys in the Rio de la Plata estuary and its inner continental shelf were analyzed from 1975 to 1995. The first two factors of Principal Component Analysis explained 48% of the variance in species distribution, and they are consistent with the results of a cluster analysis. The analysis indicated the existence of three spatially and temporally distinct fish assemblages: internal and external estuarine and inner continental shelf (Uruguayan coastal assemblages. These assemblages were persistent considering the environmental characteristics and their species composition. Despite the changes registered in the species density during the period surveyed, the fish assemblages tend to persist over time. It was demonstrated that the assemblages can be considered as open systems and that there exists a reciprocal flow of organisms between adjacent associations. However, each assemblage showed high spatial and temporal persistence in accordance with the environmental characteristics of the system analyzed. Therefore, and according to the multispecies fisheries operating in the system, each assemblage defined could be considered a unit of management.Foram analisadas as associações dos peixes demersais provenientes de arrastos de prospecção no estuário do Rio de la Plata e sua plataforma interna no período de 1975 a 1995. Os dois primeiros fatores da Análise de Componentes Principais explicaram 48% da variância na distribuição das espécies sendo consistentes com os resultados da análise de agrupamento. Os resultados mostraram a existência de três associações de peixes espacial e temporalmente distintas: uruguaia costeira, estuarina externa e estuarina interna. Essas associações foram consistentes quanto às características ambientais e de composição de espécies. A despeito das mudanças registradas na densidade das espécies ao longo do período analisado, as associações de peixes foram

  12. Short time-scale wind forced variability in the Río de la Plata Estuary and its role on ichthyoplankton retention

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    Simionato, C. G.; Berasategui, A.; Meccia, V. L.; Acha, M.; Mianzan, H.

    2008-01-01

    The Río de la Plata Estuary presents a strong bottom salinity front located over a submerged shoal. Apparently favored by retention processes, it is a spawning ground for several coastal fishes. This estuary is very shallow and essentially wind driven and, moreover, in time scales relevant to biota, estuarine circulation is wind dominated and highly variable. Two intriguing questions are, therefore, how this system can favor retention and what the involved mechanisms are. This paper qualitatively explores mechanisms involved in the estuary where retention is favored applying numerical simulations in which neutral particles - simulating fish eggs and early larvae - are released along the bottom frontal zone and tracked for different wind conditions. Results suggest that retentive features can be a consequence of estuarine response to natural wind variability acting over bathymetric features. For winds from most directions, particles either remain trapped near their launching position or move northeastward to southwestward along the shoal. As alternation of winds that favor along-shoal motion is the dominant feature of wind variability in the region, a retentive scenario results from prevailing wind variability. Additionally, winds that tend to export particles with a poor chance of being restored to the front are neither frequent nor persistent. Results show, therefore, that physical forcing alone might generate a retentive scenario at the inner part of this estuary. The physical retention mechanism is more effective for bottom than for surface launched particles. Wind statistics indicate that the proposed mechanism has different implications for retention along the seasons. Spring is the most favorable season, followed by summer, when particles would have a larger propensity to reach the southern area of the estuary (Samborombón Bay). Fall and winter are increasingly less favorable. All these features are consistent with patterns observed in the region in

  13. Copper, lead and zinc distribution in soils and sediments of the South-Western coast of the Rio de la Plata Estuary

    Energy Technology Data Exchange (ETDEWEB)

    Camilion, M.C.; Hurtado, M.A. [CISAUA-UNLP: Centro de Investigaciones de Suelos y Aguas de Uso Agropecuario, Facultad de Ciencias Naturales y Museo, Univ. Nacional de La Plata, La Plata (Argentina); Manassero, M.J. [CIG-UNLP-CONICET: Centro de Investigaciones Geologicas, Facultad de Ciencias Naturales y Museo, Univ. Nacional de La Plata, La Plata (Argentina); Ronco, A.E. [CIMA-UNLP-CONICET: Centro de Investigaciones del Medio Ambiente, Facultad de Ciencias Exactas, Univ. Nacional de La Plata, La Plata (Argentina)

    2003-07-01

    The compositional study of suspended matter in water from rivers of different latitudes and climates has revealed that the fine fraction reflects both substrate lithology from source areas or topsoil composition along the course. Metal distribution patterns are also strongly related to the clay mineral fate in fluvial aquatic systems. For the particular case of the coastal area of the Rio de la Plata estuary in South America, previous studies have, on the one hand, focused on the analysis of distribution patterns of heavy metals in bottom river sediments and, on the other hand, on the assessment of metal contents in topsoils. The present study was conducted to evaluate the Cu, Pb and Zn distribution in soils and sediments from four drainage basins crossing two differentiated geomorphologic units composed of unconsolidated materials and to understand the metal behaviour. (orig.)

  14. Life-history, substrate choice and Cytochrome Oxidase I variations in sandy beach peracaridans along the Rio de la Plata estuary

    Science.gov (United States)

    Fanini, L.; Zampicinini, G.; Tsigenopoulos, C. S.; Barboza, F. R.; Lozoya, J. P.; Gómez, J.; Celentano, E.; Lercari, D.; Marchetti, G. M.; Defeo, O.

    2017-03-01

    Life-history, substrate choice and Cytochrome Oxidase I (COI) sequences were analysed in populations of two peracaridans, the supralittoral talitrid Atlantorchestoidea brasiliensis and the intertidal cirolanid Excirolana armata. Three populations of each species, from beaches with similar grain size and located at different points along the natural gradient generated by the Rio de la Plata estuary were analysed. Abundance of E. armata increased with distance from the estuary, while the opposite trend was observed for A. brasiliensis. The proportion of females decreased towards high salinities for both species, significantly for E. armata. A test on substrate salinity preference revealed the absence of patterns due to active choice in E. armata. By contrast, A. brasiliensis showed no preference for the population closer to the estuary, while individuals from the other two sites significantly preferred high salinity substrates. Mitochondrial COI sequences were obtained from A. brasiliensis specimens tested for behaviour. Sequence analysis showed the population from the intermediate site to differ significantly from the other two. No significant genetic differentiation was instead found between populations from the two most distant sites, nor between individuals that expressed different salinity preference. Results showed that diverse sets of traits at the population level enable sandy beach species to cope with local environmental changes: life-history and behavioural traits appear to change in response to different ecological conditions, and, in the case of A brasiliensis, independently of the population structure inferred from COI sequence variation. Information from multiple traits allowed detection of population profiles, highlighting the relevance of multidisciplinary information and the concurrent analysis of field data and laboratory experiments, to detect responses of resident biota to environmental changes.

  15. Oil spill in the Rio de la Plata estuary, Argentina: 1. Biogeochemical assessment of waters, sediments, soils and biota

    International Nuclear Information System (INIS)

    Colombo, J.C.; Barreda, A.; Bilos, C.; Cappelletti, N.; Demichelis, S.; Lombardi, P.; Migoya, M.C.; Skorupka, C.; Suarez, G.

    2005-01-01

    Aliphatic (ALI) and aromatic (ARO) hydrocarbon concentrations, composition and sources were evaluated in waters, sediments, soils and biota to assess the impact of ∼1000 tons of oil spilled in Rio de la Plata coastal waters. Total ALI levels ranged from 0.4-262 μg/l in waters, 0.01-87 μg/g in sediments, 5-39 μg/g in bivalves, 12-323 μg/g in macrophytes to 948-5187 μg/g in soils. ARO varied from non-detected 10 μg/l, 0.01-1.3 μg/g, 1.0-16 μg/g, 0.5-6.9 μg/g to 22-67 μg/g, respectively. Offshore (1, 5, 15 km) waters and sediments were little affected and contained low background hydrocarbon levels reflecting an effective wind-driven transport of the slick to the coast. Six months after the spill, coastal waters, sediments, soils and biota still presented very high levels exceeding baseline concentrations by 1-3 orders of magnitude. UCM/resolved aliphatic ratio showed a clear trend of increasing decay: coastal waters (3.3) n-C23) and petrogenic/pyrogenic relationship (methylated/unsubstitued PAH) discriminated the samples according to the different degree of impact. The following paper present the results of the study of the progress of hydrocarbon disappearance in sediments and soils 13 and 42 months after the spill. - The Oil spill impact the Rio de la Plata was evaluated by HRGC and multivariate techniques applied to waters, sediments and biota

  16. Otolith morphology and body size relationships for juvenile Sciaenidae in the Río de la Plata estuary (35-36°S

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    Juan A. Waessle

    2003-06-01

    Full Text Available Seven species of the family Sciaenidae have been reported inhabiting bottom waters of the Río de la Plata estuary. Of these juvenile stripped weakfish (Cynoscion guatucupa, king weakfish (Macrodon ancylodon, whitemouth croaker (Micropogonias furnieri and banded ground drum (Paralonchurus brasiliensis are by far the most abundant. These species are also important prey of several top-predator species among large fishes, seabirds and mammals. In this study we provide new information regarding otolith morphology and body size relationships of juvenile sciaenid fish. The sagittae morphology of juvenile sciaenids showed strong changes in the course of their development (e.g. in overall shape and development of concrescences on the outer surface. Analysing the morphometric relationships, we concluded that otolith length and otolith mass are good indicators of fish standard length and fish weight in all species. If otolith length or mass is used to estimate fish length, the regression explained more than 97% of the variation in all species. All equations relating fish standard length and fish weight for juvenile stages of the species studied explained a very large proportion of the variance in the data. These data will help researchers studying food habits of top predators to determine size and weight of usually juvenile fish-prey from length, broad and/or weight of recovered otoliths.

  17. Use of phytoplankton assemblages to assess the quality of coastal waters of a transitional ecosystem: Río de la Plata estuary

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    Sathicq, María Belén; Gómez, Nora; Bauer, Delia Elena; Donadelli, Jorge

    2017-11-01

    Among the estuarine ecosystems under anthropogenic stress, the Río de la Plata can represent a case study to help identify phytoplanktonic species diagnosing and warning about water quality changes. The freshwater tidal zone on the coast of Argentina is used for several purposes, including recreational and navigational activities and the provision of drinking water. We analyzed the relationship between the abundance of the phytoplanktonic species, changes in water quality (linked to enrichment with nutrients and organic matter) and the land use on the coast of Argentina. A canonical correlation analysis (CCA) allowed us to identify two environmental gradients, one related to anthropogenic activities, where the most influential factors were BOD5, DIN, PO43- and DO, and a second gradient related to turbidity and conductivity. The relative abundances of 24 species were significantly correlated with the deterioration of the water quality. This set of tolerant species is mostly composed of taxa considered C-strategists, and the most represented group was the Chlorococcalean algae. The percentage of this group can provide an early warning indicator of the impairment of the water quality; its abundance exceeded 30% at those sites with a bad water quality (reaching 19000 cell mL-1), and were less than 15% (300 cell mL-1) in sites with a good water quality. The use of a reduced group of species constitutes a potential tool for monitoring, complementing another common indicators such as chlorophyll a or the total density of phytoplankton. Considering that most of these tolerant species are widely distributed it is possible to employ them as a biomonitor in other freshwater zones of temperate estuaries.

  18. First record of the invasive medusa Blackfordia virginica (Hydrozoa: Leptomedusae in the Río de la Plata estuary, Argentina-Uruguay Primer registro de la medusa invasora Blackfordia virginica (Hydrozoa: Leptomedusae en el estuario del Río de la Plata, Argentina-Uruguay

    Directory of Open Access Journals (Sweden)

    GABRIEL GENZANO

    2006-06-01

    Full Text Available Blackfordia virginica is a well-known invasive medusa inhabiting estuarine areas. It was recently detected in northern Argentina, constituting the first record of invasive hydromedusa for the Argentine Sea. In this work more than 1,500 plankton samples in the southwestern Atlantic Ocean (34-55º S from 1983 to 2000 were analyzed. More than 5,000 specimens per sample of B. virginica were found in Río de la Plata estuary for the first time in February 2000. This river is one of the large waterways of South America with an intense nautical traffic and several exotic species has been recorded here, mainly due to trans-oceanic shipping traffic. It is important to point out that we found medusae of both sexes (therefore this species could be introduced in either the medusa or the polyp stages or both, different size classes (including very small juveniles and maturation stages, and in such high numbers that would suggest local reproduction. For this reason the recent finding of this hydromedusa could represent the starting point of an successful introductionBlackfordia virginica es una medusa invasora reconocida por habitar áreas estuariales. Recientemente fue descubierta en el norte de Argentina, constituyendo el primer registro de una hidromedusa invasora para el mar argentino. En este trabajo se analizaron más de 1.500 muestras de plancton en el Océano Atlántico sudoccidental (34-55º S desde 1983 hasta el año 2000. Más de 5.000 especímenes por muestra fueron encontrados por primera vez en el estuario del Río de la Plata durante febrero del año 2000. Este río es una de las mayores vías de agua de América del Sur, posee un intenso tráfico náutico y varias especies exóticas se han registrado allí, principalmente debido al tráfico marítimo transoceánico. Es importante señalar que se encontraron medusas de ambos sexos (por lo tanto esta especie podría haber sido introducida en su estadio medusa, pólipo o ambos, con diferentes

  19. The relative importance of oceanic nutrient inputs for Bass Harbor Marsh Estuary at Acadia National Park, Maine

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    Huntington, Thomas G.; Culbertson, Charles W.; Fuller, Christopher; Glibert, Patricia; Sturtevant, Luke

    2014-01-01

    The U.S. Geological Survey and Acadia National Park (ANP) collaborated on a study of nutrient inputs into Bass Harbor Marsh Estuary on Mount Desert Island, Maine, to better understand ongoing eutrophication, oceanic nutrient inputs, and potential management solutions. This report includes the estimation of loads of nitrate, ammonia, total dissolved nitrogen, and total dissolved phosphorus to the estuary derived from runoff within the watershed and oceanic inputs during summers 2011 and 2012. Nutrient outputs from the estuary were also monitored, and nutrient inputs in direct precipitation to the estuary were calculated. Specific conductance, water temperature, and turbidity were monitored at the estuary outlet. This report presents a first-order analysis of the potential effects of projected sea-level rise on the inundated area and estuary volume. Historical aerial photographs were used to investigate the possibility of widening of the estuary channel over time. The scope of this report also includes analysis of sediment cores collected from the estuary and fringing marsh surfaces to assess the sediment mass accumulation rate. Median concentrations of nitrate, ammonium, and total dissolved phosphorus on the flood tide were approximately 25 percent higher than on the ebb tide during the 2011 and 2012 summer seasons. Higher concentrations on the flood tide suggest net assimilation of these nutrients in biota within the estuary. The dissolved organic nitrogen fraction dominated the dissolved nitrogen fraction in all tributaries. The median concentration of dissolved organic nitrogen was about twice as high on the on the ebb tide than the flood tide, indicating net export of dissolved organic nitrogen from the estuary. The weekly total oceanic inputs of nitrate, ammonium, and total dissolved phosphorus to the estuary were usually much larger than inputs from runoff or direct precipitation. The estuary was a net sink for nitrate and ammonium in most weeks during both

  20. Residual fluxes of water and nutrient transport through the main inlet of a tropical estuary, Cochin estuary, West Coast, India

    Digital Repository Service at National Institute of Oceanography (India)

    Vinita, J.; Lallu, K.R; Revichandran, C.; Muraleedharan, K.R; Jineesh, V.K.; Shivaprasad, A.

    of Oceanic Engineering, 25(4), 437-445. 13    Sooria, P.M., Jyothibabu, R., Anjusha, A., Vineetha, G., Vinita, J., Lallu, K. R., Paul, M., Jagadeesan, L., et al. (2015). Plankton food web and its seasonal dynamics in a large monsoonal estuary (Cochin... J., Lallu K.R., Muraleedharan K. R., Jineesh V.K., Shivaprasad A. Abstract Determining robust values for estuarine material fluxes has been a complex task and an interdisciplinary research challenge. With the advent of Acoustic Doppler...

  1. Nutrient Enrichment in Estuaries from Discharge of Shallow Ground Water, Mt. Desert Island, Maine

    Science.gov (United States)

    Culbertson, Charles W.; Huntington, Thomas G.; Caldwell, James M.

    2007-01-01

    Nutrient enrichment from atmospheric deposition, agricultural activities, wildlife, and domestic sources is a concern at Acadia National Park because of the potential problem of water-quality degradation and eutrophication in its estuaries. Water-quality degradation has been observed at the Park?s Bass Harbor Marsh estuary but not in Northeast Creek estuary. Previous studies at Acadia National Park have estimated nutrient inputs to estuaries from atmospheric deposition and surface-water runoff, but the importance of shallow ground water that may contain nutrients derived from domestic or other sources is unknown. Northeast Creek and Bass Harbor Marsh estuaries were studied to (1) identify shallow ground-water seeps, (2) assess the chemistry of the water discharged from selected seeps, and (3) assess the chemistry of ground water in shallow ground-water hyporheic zones. The hyporheic zone is defined here as the region beneath and lateral to a stream bed, where there is mixing of shallow ground water and surface water. This study also provides baseline chemical data for ground water in selected bedrock monitoring wells and domestic wells on Mt. Desert Island. Water samples were analyzed for concentrations of nutrients, wastewater compounds, dissolved organic carbon, pH, dissolved oxygen, temperature and specific conductance. Samples from bedrock monitoring wells also were analyzed for alkalinity, major cations and anions, and trace metals. Shallow ground-water seeps to Northeast Creek and Bass Harbor Marsh estuaries at Acadia National Park were identified and georeferenced using aerial infrared digital imagery. Monitoring included the deployment of continuously recording temperature and specific conductance sensors in the seep discharge zone to access marine or freshwater signatures related to tidal flooding, gradient-driven shallow ground-water flow, or shallow subsurface flow related to precipitation events. Many potential shallow ground-water discharge zones were

  2. Short-term toxicity of hexavalent-chromium to epipsammic diatoms of a microtidal estuary (Río de la Plata): Responses from the individual cell to the community structure

    International Nuclear Information System (INIS)

    Licursi, M.; Gómez, N.

    2013-01-01

    Highlights: •Diatom's nuclear abnormalities were significantly higher as consequence of chromium exposure. •Diatoms and chlorophytes increased in treatment microcosms. •Nitzschia palea proportion increased significantly in the treatment microcosms. -- Abstract: Diatoms are an integral and often dominant component of the benthic microalgal assemblage in estuarine and shallow coastal environments. Different toxic substances discharged into these ecosystems persist in the water, sediments, and biota for long periods. Among these pernicious agents, the toxicity in diatoms by metal is linked to different steps in the transmembrane and internal movements of the toxicant, causing perturbations in the normal structural and functional cellular components. These changes constitute an early, nontaxonomic warning signal that could potentially serve as an indicator of this type of pollution. The aim of this work was to study the environment-reflecting short-term responses at different levels of organization of epipsammic diatoms from the Río de la Plata estuary, Argentina that had been exposed to hexavalent chromium within experimental microcosms. To this end we monitored: (i) changes in the proportion of the diatoms in relation to other algal groups at the biofilm community level; (ii) shifts in species composition at the diatom-assemblage level; (iii) projected changes in the densities of the most representative species at the population level through comparison of relative growth rates and generation times; and (iv) the cytological changes at the cellular and subcellular levels as indicated by the appearance of teratological effects on individuals and nuclear alterations. The epipsammic biofilms were exposed for 96 h to chromium at a concentration similar to that measured in highly impacted sites along the coast (80 μg L −1 ). Chromium pollution, at this concentration and short exposure time did not affect the algal biomass and density of these mature biofilms. The

  3. Short-term toxicity of hexavalent-chromium to epipsammic diatoms of a microtidal estuary (Río de la Plata): Responses from the individual cell to the community structure

    Energy Technology Data Exchange (ETDEWEB)

    Licursi, M., E-mail: malena@ilpla.edu.ar; Gómez, N.

    2013-06-15

    Highlights: •Diatom's nuclear abnormalities were significantly higher as consequence of chromium exposure. •Diatoms and chlorophytes increased in treatment microcosms. •Nitzschia palea proportion increased significantly in the treatment microcosms. -- Abstract: Diatoms are an integral and often dominant component of the benthic microalgal assemblage in estuarine and shallow coastal environments. Different toxic substances discharged into these ecosystems persist in the water, sediments, and biota for long periods. Among these pernicious agents, the toxicity in diatoms by metal is linked to different steps in the transmembrane and internal movements of the toxicant, causing perturbations in the normal structural and functional cellular components. These changes constitute an early, nontaxonomic warning signal that could potentially serve as an indicator of this type of pollution. The aim of this work was to study the environment-reflecting short-term responses at different levels of organization of epipsammic diatoms from the Río de la Plata estuary, Argentina that had been exposed to hexavalent chromium within experimental microcosms. To this end we monitored: (i) changes in the proportion of the diatoms in relation to other algal groups at the biofilm community level; (ii) shifts in species composition at the diatom-assemblage level; (iii) projected changes in the densities of the most representative species at the population level through comparison of relative growth rates and generation times; and (iv) the cytological changes at the cellular and subcellular levels as indicated by the appearance of teratological effects on individuals and nuclear alterations. The epipsammic biofilms were exposed for 96 h to chromium at a concentration similar to that measured in highly impacted sites along the coast (80 μg L{sup −1}). Chromium pollution, at this concentration and short exposure time did not affect the algal biomass and density of these mature

  4. Holocene depositional history of a large glaciated estuary, Penobscot Bay, Maine

    Science.gov (United States)

    Knebel, H.J.

    1986-01-01

    Data from seismic-reflection profiles, sidescan sonar images, and sediment samples reveal the Holocene depositional history of the large (1100 km2) glaciated Penobscot Bay estuary of coastal Maine. Previous work has shown that the late Wisconsinan ice sheet retreated from the three main passages of the bay between 12,700 and 13,500 years ago and was accompanied by a marine transgression during which ice and sea were in contact. Isostatic recovery of the crust caused the bay to emerge during the immediate postglacial period, and relative sea level fell to at least -40 m sometime between 9000 and 11,500 years ago. During lowered sea level, the ancestral Penobscot River flowed across the subaerially exposed head of the bay and debouched into Middle Passage. Organic-matter-rich mud from the river was deposited rapidly in remnant, glacially scoured depressions in the lower reaches of Middle and West Passages behind a shallow (???20 m water depth) bedrock sill across the bay mouth. East Passage was isolated from the rest of the bay system and received only small amounts of locally derived fine-grained sediments. During the Holocene transgression that accompanied the eustatic rise of sea level, the locus of sedimentation shifted to the head of the bay. Here, heterogeneous fluvial deposits filled the ancestral valley of the Penobscot River as base level rose, and the migrating surf zone created a gently dipping erosional unconformity, marked by a thin (energy conditions and the waning influence of the Penobscot River at the head of the bay. In contrast, relatively thick (up to 25 m) silty clays accumulated within a subbottom trough in the western half of the bay head. This deposit apparently developed late in the transgression after sea level had reached -20 m and after the westward transport of fine-grained sediments from the Penobscot River had been established. During and since the late Holocene transgression of sea level, waves and currents have eroded, reworked, and

  5. More than two decades after the introduction of Limnoperna fortunei (Dunker 1857 in La Plata Basin

    Directory of Open Access Journals (Sweden)

    M. A. Pessotto

    2018-01-01

    Full Text Available Abstract The golden mussel, Limnoperna fortunei, is an Asian freshwater bivalve introduced in South America in the beginning of the 1990’s, probably through ballast water releases in La Plata River estuary. It dispersed north through Paraná, Uruguay and Paraguay Rivers. The study evaluated the macroscale (18° to 34° S; 45° to 60° W distribution of L. fortunei (larval stages in the main rivers and reservoirs of La Plata Basin. Samplings were performed through 68 µm vertical plankton net hauls. Limnological variables were simultaneously determined. Larvae abundance correlated significantly with oxygen (positively in summer, with temperature (positively in winter and with total phosphorus and total nitrogen (both negatively in winter. We expected densities to decrease towards north (latitudinal gradient and increase in lentic conditions (reservoirs. Despite maximum density was found near the introduction point (La Plata River similar value was also observed 2,000 km north (Paraguay River. The first hypothesis was refuted. The second hypothesis was partially accepted. Abundances were consistently higher in summer. Higher trophic conditions and fast flow seem to inhibit population growth. Food resources (chlorophyll a locally influenced temporal variation. Limnoperna fortunei is widely distributed in La Plata basin, reaching high larval densities superior to 10,000 ind. m-3, in all major sub-basins. The species exhibits a high intrinsic dispersal ability (free planktonic larvae, wide tolerance to environmental factors and dispersion is potentialized by natural dispersion processes (e.g. fauna displacement and human facilitation (e.g. commercial navigation.

  6. Sediment accumulation and mixing in the Penobscot River and estuary, Maine.

    Science.gov (United States)

    Yeager, K M; Schwehr, K A; Schindler, K J; Santschi, P H

    2018-04-16

    Mercury (Hg) was discharged in the late 1960s into the Penobscot River by the Holtra-Chem chlor-alkali production facility, which was in operation from 1967 to 2000. To assess the transport and distribution of total Hg, and recovery of the river and estuary system from Hg pollution, physical and radiochemical data were assembled from sediment cores collected from 58 of 72 coring stations sampled in 2009. These stations were located throughout the lower Penobscot River, and included four principal study regions, the Penobscot River (PBR), Mendall Marsh (MM), the Orland River (OR), and the Penobscot estuary (ES). To provide the geochronology required to evaluate sedimentary total Hg profiles, 58 of 72 sediment cores were dated using the atmospheric radionuclide tracers 137 Cs, 210 Pb, and 239,240 Pu. Sediment cores were assessed for depths of mixing, and for the determination of sediment accumulation rates using both geochemical (total Hg) and radiochemical data. At most stations, evidence for significant vertical mixing, derived from profiles of 7 Be (where possible) and porosity, was restricted to the upper ~1-3cm. Thus, historic profiles of both total Hg and radionuclides were only minimally distorted, allowing a reconstruction of their depositional history. The pulse input tracers 137 Cs and 239,240 Pu used to assess sediment accumulation rates agreed well, while the steady state tracer 210 Pb exhibited weaker agreement, likely due to irregular lateral sediment inputs. Copyright © 2018. Published by Elsevier B.V.

  7. Visits to La Plata Observatory

    Science.gov (United States)

    Feinstein, A.

    1985-03-01

    La Plata Observatory will welcome visitors to ESO-La Silla that are willing to make a stop at Buenos Aires on their trip to Chile or on their way back. There is a nice guesthouse at the Observatory that can be used, for a couple of days or so, by astronomers interested in visiting the Observatory and delivering talks on their research work to the Argentine colleagues. No payments can, however, be made at present. La Plata is at 60 km from Buenos Aires. In the same area lie the Instituto de Astronomia y Fisica dei Espacio (IAFE), in Buenos Aires proper, and the Instituto Argentino de Radioastronomia (IAR). about 40 km from Buenos Aires on the way to La Plata. Those interested should contacl: Sr Decano Prof. Cesar A. Mondinalli, or Dr Alejandro Feinstein, Observatorio Astron6mico, Paseo dei Bosque, 1900 La Plata, Argentina. Telex: 31216 CESLA AR.

  8. A Numerical Study of the Plata River Plume Along the Southeastern South American Continental Shelf

    Science.gov (United States)

    2005-01-01

    the effect of ambient shelf currents, level decreased by -0.20 and -0.55 in at the estuary and which would be essential in the determination of the 142...Res. SI 39, realistic wind and tidal forcing. J. Geophys. Res., 101 (submitted). (C2):3435-3455. Piola, A. R. 2002. El impacto del Plata sobre la...discharge on the continental impactos en el Plata y en la regi6n pampeana. Vol. 1. shelf. 1. Modeling the river plume and the inner shelf Assoc. Bonaerense de

  9. Simulation of the transport of suspended particulate matter in the Rio de la Plata

    Energy Technology Data Exchange (ETDEWEB)

    Hausstein, H.

    2008-11-06

    Numerical simulations of the transport of Suspended Particulate Matter in the Rio de la Plata estuary were performed with a three dimensional model for coastal waters driven by wave sand currents. Aturbulence based flocculation approach is implemented to the model. The model is for the first time applied under heavy conditions, since the Rio de la Plata has discharges up to 25000 m{sup 3}/s and SPM concentrations up to 300-400 mg/l. Such concentrations are also difficult to compute from satellite measurements. SeaWiFs satellite images served for the validation of the model results. The model is able to reproduce the shape and the position of the front as well as the zone of the turbidity maximum. It also identifies the zones of erosion and deposition which is of significant importance because of the dense ship traffic along the navigational channels towards Buenos Aires and the cities upstream the rivers. (orig.)

  10. Geology of the Río de la Plata and the surrounding areas of Argentina and Uruguay related to the evolution of the Atlantic margin

    Science.gov (United States)

    Rossello, Eduardo A.; Veroslavsky, Gerardo; de Santa Ana, Héctor; Rodríguez, Pablo

    2018-04-01

    An integrated study of geological and geophysical data of the Río de la Plata region and its relation to the evolution of the Atlantic passive margin is herein described. This characterization is based on the available geological and geophysical information and on the correlation of the southern end of the best-known Santa Lucía Basin in Uruguay to the Salado Basin in Argentina, and their connection through the Quilmes Trough. Furthermore, a new Meso-Cenozoic depocenter is characterized and identified as Recalada Trough, subparallely aligned to the Quilmes Trough and separated from it by the Magdalena-Montevideo High. Both sedimentary fillings present ENE-WSW trending main axes and reach an average thickness of almost 2000 m. This suggests an evolution from a triple junction where interconnected extensional arms developed, which have had common Mesozoic tectosedimentary histories related to the early opening of the Atlantic Ocean. Based on the geophysical and geological evidence, the previously accepted existence in the Río de la Plata of a first-order structural feature along the international border between Argentina and Uruguay, associated to an ENE-WSW trending tectonic high, identified as Martín García, is unjustified. The tectonic evolution of the Atlantic margin in front of the Río de la Plata estuary is the consequence of a long deformation history starting in the Precambrian up to recent times. Each Precambrian, Paleozoic, Mesozoic and Cenozoic tectonic scenario adds different weak trends on the continental crust, which control the evolution of the sedimentary depocenters. The presence of these tectosedimentary records influence the bathymetric control of the Río de la Plata and the dynamics of the recent estuarine deposits. The Meso-Cenozoic sedimentary infill is estimated to comprise considerable ranges of sandstones and conglomerates associated with faulted blocks of the crystalline basement, with expected petrophysical conditions oscillating in

  11. A trans-ecosystem fishery: Environmental effects on the small-scale gillnet fishery along the Río de la Plata boundary

    Science.gov (United States)

    Jaureguizar, Andrés Javier; Cortés, Federico; Milessi, Andrés Conrado; Cozzolino, Ezequiel; Allega, Lucrecia

    2015-12-01

    To improve the understanding of the environmental processes affecting small-scale gillnet fisheries along neighboring waters of estuaries, we analyzed the main climatic forcing and the environmental conditions, the fishery landing spatial and temporal variation, including the relative importance of site, distance to coast, temperature and salinity in the structuring of landed species profile. Data were collected monthly in two sites along the adjacent south coast of the Río de la Plata between October 2009 and September 2010. The gillnet fishery was dominated by four species (Cynoscion guatucupa, Micropogonias furnieri, Mustelus schmitti and Parona signata) from a total of 38 species landed, which accounted for 98.6% of total landings. The fishing effort and landings by the fishery were largely conditioned by the availability of fish species in the fishing grounds resulting from the combination of the species reproductive behavior and the predominant environmental conditions. The highest abundances for some species occurred before (M. furnieri, C. guatucupa, P. signata) or during the reproductive period (M. schmitti, Squatina guggenheim), while in other species it was associated with favorable environmental conditions during cold months (Squalus acanthias, Callorhinchus callorhynchus, Galeorhinus galeus) or warm months (Trichiurus lepturus). The predominant seasonal environmental conditions along the coast were mainly determined by the location of Río de la Plata boundary, whose spatial extent was forced by the wind patterns and freshwater discharge. The strong environmental dependence means that the small-scale fishery is in fact a seasonal trans-ecosystem fishery. This attribute, together that shared the resources with the industrial fishery and the overlap of the fishery ground with essential habitat of sharks, make this kind of small-scale gillnet fishery particularly relevant to be included in the development of a coastal ecosystem-based management approach.

  12. Phylogeography of the Neotropical catfish Pimelodus albicans (Siluriformes: Pimelodidae from río de la Plata basin, South America, and conservation remarks

    Directory of Open Access Journals (Sweden)

    Julia Vergara

    Full Text Available Pimelodus albicans Valenciennes, 1840 (common name "moncholo" or "bagre blanco" is an endemic species of the family Pimelodidae in the río de la Plata basin. Phylogenetic approach based on cytochrome b sequences was performed to test the existence of a unique evolutionary lineage in P. albicans and to discriminate populations units or subpopulations related to a migration behavior of this taxon in the río de la Plata basin. This study included 34 samples of P. albicans of different collecting sites in the río de la Plata estuary and in the río Arrecifes belonging to the río Paraná basin. Among 614 base pairs in the cytochrome b sequence data set, 203 were variable and 120 were phylogenetically informative sites in P. albicans. A total of twenty haplotypes, nucleotide diversity (p = 0.032 and haplotype diversity = 0.941 were found. Tajima's test showed significant value D= -1.88 (p<0.05 rejecting the neutral mutation hypothesis for the P. albicans data set. All phylogenetic approaches showed that P. albicans included four monophyletic assemblages that were supported by high bootstrap and Bayesian posterior probability values. Minimum spanning network corroborated these groups for P. albicans haplotypes. High genetic structure was found in P. albicans by means of AMOVA analysis showing that the río Arrecifes samples constitute an isolated lineage. Moreover, the high value of genetic divergence (10% between the río de la Plata and the río Arrecifes populations could suggest that P. albicans may be conformed by a sibling species complex. On the other hand, a degree of genetic structuring was detected among different sites of the río de la Plata. A partial isolation of the 760 site may suggest that P. albicans could migrates to different tributaries for reproduction, generating different schools of haplotypes which could mix in the río de la Plata estuary. The high nucleotide diversity found in the 765 site and the existence of gene flow

  13. FLORA OF MOLOCHNYI ESTUARY COASTS

    Directory of Open Access Journals (Sweden)

    Kolomiychuk V.P.

    2013-09-01

    Full Text Available Present-day characteristic of the coastal flora of Molochnyi eastury is given, that is one of the largest estuaries in Ukraine, the shores and waters of which in 2009 became a part of the Pryazov’ya National Nature Park. The analysis of the main parameters of the flora is made. Rare component of the estuary coastal flora is characterized, further steps to conserve the nature of Pryazov’ya are proposed.

  14. Cenozoic deposits exposed along Rio de la Plata coast in the Canelones Department (Uruguay)

    International Nuclear Information System (INIS)

    Goso Aguilar, C.; Spoturno, J.

    2004-01-01

    This paper allows to know some sedimentological and stratigraphical features of the Cenozoic deposits exposed along Rio de la Plata coast in the Canelones department, Uruguay. The results, mainly collected from metric thickness of local stratigraphical sections and coastal outcrops of that region are presented. Both Tertiary and Quaternary sediments are present, however transitional Pleistocenic deposits of Chuy Formation and continental sediments of Libertad Formation are more dominant [es

  15. Origin of resources and trophic pathways in a large SW Atlantic estuary: An evaluation using stable isotopes

    Science.gov (United States)

    Botto, Florencia; Gaitán, Esteban; Mianzan, Hermes; Acha, Marcelo; Giberto, Diego; Schiariti, Agustín; Iribarne, Oscar

    2011-03-01

    The Río de la Plata (34° 36' S, 55° 58' W; Argentina and Uruguay) estuary, one of the most important South American estuarine environments, is characterized by weak seasonal freshwater discharge, low tidal amplitude (freshwater marshes both contribute to the food web of the Río de la Plata estuary. On the basis of the sampled species, we identified four trophic levels. The clam Mactra isabelleana, the calanoid copepod Acartia tonsa, and the opossum shrimp Neomysis americana are the primary consumers. The rays Atlantoraja castelnaui and Squatina guggenheim and the shark Galeorhinus galeus are the top predators. The Río de la Plata food web shows an important input of nutrients derived from phytoplankton. Rays, sharks, and predatory gastropods reveal an important contribution of C4 plants (likely Spartina spp.). However, production derived from C3 plants is also important for some species. The fishes Brazilian menhaden, Brevoortia aurea; the stripped weakfish Cynoscion guatucupa; and the whitemouth croaker, Micropogonias furnieri, showed differences in their isotopic signatures as juveniles and adults, indicating different food sources, and they were therefore treated as different components of the food web. Our data suggest that detritus from salt and freshwater marshes is reaching the Río de la Plata estuary and can be an important allocthonous source of energy to this environment.

  16. Human toxocarosis. Its seroprevalence in the City of La Plata

    Directory of Open Access Journals (Sweden)

    NE Radman

    2000-06-01

    Full Text Available Toxocara canis is very common in dogs throughout the world. It is the primary cause of visceral larva migrans (VLM in humans. Soil contaminated with T. canis embryonated eggs is the main source of infection of man. Our objective was to describe Toxocara seroprevalence in humans in the city of La Plata associated with some determinants such asage, presence or absence of clinical manifestations and risk factors. Blood samples were collected at random from 156 patients of different sex and age, with and without clinical symptoms compatible with the disease. The diagnostic technique ELISA test was performed with the Bordier Affinity Products Commercial Kit, using excretory-secretory Toxocara antigen with a sensitivity higher than 90%. The values were positive in 39% of the studied population. In the analysis according to age, the younger group presented significant differences with respect to the older one (Chi-square p<0.05. Positive patients presented clinical symptoms compatible with the disease (84%, and 41% presented some risk factor. The level of positivity obtained indicates a certain risk of being infectes mainly in patients younger than 15 years old. The authors agree that an early identification and treatment of VLM may save a life.

  17. Seasonal and inter-annual turbidity variability in the Rio de la Plata from 15 years of MODIS: El Niño dilution effect

    OpenAIRE

    Dogliotti, A.I.; Ruddick, K.; Guerrero, R.

    2016-01-01

    Spatio-temporal variability of turbidity in the Río de la Plata (RdP) estuary (Argentina) at seasonal and inter-annual timescales is analyzed from 15 years (2000–2014) of MODIS data and explained in terms of river discharges and the El Niño Southern Oscillation (ENSO). Satellite estimates were first validated using in situ turbidity measurements and then the time series of monthly averages were analyzed to assess the seasonal and inter-annual variability of turbidity. A strong seasonal variab...

  18. Estuary Data Mapper (EDM)

    Science.gov (United States)

    Estuary Data Mapper is a tool for geospatial data discovery, visualization, and data download for any of the approximately 2,000 estuaries and associated watersheds in along the five US coastal regions

  19. Climate Ready Estuaries

    Science.gov (United States)

    Information on climate change impacts to different estuary regions, tools and resources to monitor changes, and information to help managers develop adaptation plans for risk management of estuaries and coastal communities.

  20. Identification of palaeo-seawater intrusion in groundwater using minor ions in a semi-confined aquifer of the Río de la Plata littoral (Argentina)

    International Nuclear Information System (INIS)

    Santucci, L.; Carol, E.; Kruse, E.

    2016-01-01

    The hydrochemistry of minor elements and traces such as bromide, lithium, strontium, uranium and selenium, together with the chemical analysis of major ions, has been used in the study of salinization process. This process occurs in a semi-confined aquifer that corresponds to a Pliocene–Pleistocene fluvial environment. The semi-confined aquifer is located in the littoral of the cities of Ensenada and Berisso, in the region of the middle Río de la Plata estuary, Argentina. Groundwater salinization was detected in the semi-confined aquifer in the coastal plain area, with salt contents that increase from the loess plain towards the river. The content of major ions that predominate in sea water (Cl"−, Na"+ and Mg"2"+), as well as the Cl"−/Br"− and U vs. Cl"− ratios, demonstrates that such salinization is related to sea water, which shows no correspondence with estuary water. In the salinized area, Li, Sr and Se enrichments occur, and are used as tracers of the average time that a substance remains in solution in sea water in the aquifer. The study of such minor ions together with the geological evolution of the area made it possible to recognize that the salt water in the semi-confined aquifer corresponds to a palaeo-intrusion of sea water associated with the Pleistocene–Holocene ingressions caused by the climate changes occurring during the Quaternary. - Highlights: • The semi-confined aquifer in a sector of the Río de la Plata estuary is salinized. • Saline content is higher in the aquifer than in the estuary. • Minor elements indicate the occurrence of palaeo-seawater intrusion. • Palaeo-seawater intrusion may be associated with interglacial fluctuations.

  1. Identification of palaeo-seawater intrusion in groundwater using minor ions in a semi-confined aquifer of the Río de la Plata littoral (Argentina)

    Energy Technology Data Exchange (ETDEWEB)

    Santucci, L., E-mail: eleocarol@fcnym.unlp.edu.ar [Centro de Investigaciones Geológicas (CIG), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) - Universidad Nacional de La Plata - UNLP, Calle 64 y Diag. 113, 1900 La Plata, Buenos Aires (Argentina); Carol, E. [Centro de Investigaciones Geológicas (CIG), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) - Universidad Nacional de La Plata - UNLP, Calle 64 y Diag. 113, 1900 La Plata, Buenos Aires (Argentina); Kruse, E. [Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Cátedra de Hidrología General de la Facultad de Ciencias Naturales y Museo, Universidad Nacional de La Plata (UNLP), Calle 64 #3, 1900 La Plata, Buenos Aires (Argentina)

    2016-10-01

    The hydrochemistry of minor elements and traces such as bromide, lithium, strontium, uranium and selenium, together with the chemical analysis of major ions, has been used in the study of salinization process. This process occurs in a semi-confined aquifer that corresponds to a Pliocene–Pleistocene fluvial environment. The semi-confined aquifer is located in the littoral of the cities of Ensenada and Berisso, in the region of the middle Río de la Plata estuary, Argentina. Groundwater salinization was detected in the semi-confined aquifer in the coastal plain area, with salt contents that increase from the loess plain towards the river. The content of major ions that predominate in sea water (Cl{sup −}, Na{sup +} and Mg{sup 2+}), as well as the Cl{sup −}/Br{sup −} and U vs. Cl{sup −} ratios, demonstrates that such salinization is related to sea water, which shows no correspondence with estuary water. In the salinized area, Li, Sr and Se enrichments occur, and are used as tracers of the average time that a substance remains in solution in sea water in the aquifer. The study of such minor ions together with the geological evolution of the area made it possible to recognize that the salt water in the semi-confined aquifer corresponds to a palaeo-intrusion of sea water associated with the Pleistocene–Holocene ingressions caused by the climate changes occurring during the Quaternary. - Highlights: • The semi-confined aquifer in a sector of the Río de la Plata estuary is salinized. • Saline content is higher in the aquifer than in the estuary. • Minor elements indicate the occurrence of palaeo-seawater intrusion. • Palaeo-seawater intrusion may be associated with interglacial fluctuations.

  2. Natural and human forcing in recent geomorphic change; case studies in the Rio de la Plata basin.

    Science.gov (United States)

    Bonachea, Jaime; Bruschi, Viola M; Hurtado, Martín A; Forte, Luis M; da Silva, Mario; Etcheverry, Ricardo; Cavallotto, José L; Dantas, Marcilene F; Pejon, Osni J; Zuquette, Lázaro V; Bezerra, Maria Angélica de O; Remondo, Juan; Rivas, Victoria; Gómez-Arozamena, José; Fernández, Gema; Cendrero, Antonio

    2010-06-01

    An analysis of geomorphic system's response to change in human and natural drivers in some areas within the Río de la Plata basin is presented. The aim is to determine whether an acceleration of geomorphic processes has taken place in recent years and, if so, to what extent it is due to natural (climate) or human (land-use) drivers. Study areas of different size, socio-economic and geomorphic conditions have been selected: the Río de la Plata estuary and three sub-basins within its watershed. Sediment cores were extracted and dated ((210)Pb) to determine sedimentation rates since the end of the 19th century. Rates were compared with time series on rainfall as well as human drivers such as population, GDP, livestock load, crop area, energy consumption or cement consumption, all of them related to human capacity to disturb land surface. Data on river discharge were also gathered. Results obtained indicate that sedimentation rates during the last century have remained essentially constant in a remote Andean basin, whereas they show important increases in the other two, particularly one located by the São Paulo metropolitan area. Rates in the estuary are somewhere in between. It appears that there is an intensification of denudation/sedimentation processes within the basin. Rainfall remained stable or varied very slightly during the period analysed and does not seem to explain increases of sedimentation rates observed. Human drivers, particularly those more directly related to capacity to disturb land surface (GDP, energy or cement consumption) show variations that suggest human forcing is a more likely explanation for the observed change in geomorphic processes. It appears that a marked increase in denudation, of a "technological" nature, is taking place in this basin and leading to an acceleration of sediment supply. This is coherent with similar increases observed in other regions. Copyright (c) 2010 Elsevier B.V. All rights reserved.

  3. Teaching Humanities at the National University of la Plata, Argentina.

    Science.gov (United States)

    Acuña, Leopoldo E

    2003-10-01

    In this article the author begins by giving a brief history of medical education in Argentina, then provides some background information on the National University of La Plata. He describes two major initiatives at La Plata: a new and pioneering admission policy (implemented in 1993) and a change in the number of hours and years in the curriculum. He then looks back to the introduction in 1976 of La Plata's medical humanities program. Over its 20 year existence, the program has undergone a number of changes in response both to students' interests and financial concerns. The revised humanities curriculum now consists of four elective courses: medicine and literature, anthropology, history of medicine, and "medical kalology" (which focuses on music and dance). Unfortunately, the program, while it has been well received by both students and faculty and has inspired programs at other Argentinean schools, is threatened by Argentina's economic crisis.

  4. The Hydrologic Regime of the La Plata Basin in South America

    Science.gov (United States)

    Berbery, E. H.; Barros, V. R.

    2002-12-01

    The main components of the hydrologic cycle of the La Plata basin in southeastern South America are investigated using a combination of observations, satellite products and National Centers for Environmental Prediction-National Center for Atmospheric Research (NCEP-NCAR) global reanalyses. La Plata basin is second only to the Amazon basin in South America, and plays a critical role in the economies of the region. It is a primary factor in energy production, water resources, transportation, agriculture and livestock. Of particular interest was to evaluate the annual cycle of the hydrologic cycle components. The La Plata annual-mean river discharge is about 21,000 m3 s-1, and the amplitude of the mean annual cycle of La Plata River discharge is small: it is slightly larger during late summer, but continues with large volumes even during winter. The reason is that different precipitation regimes over different locations contribute to the total river discharge. One regime is found toward the northern boundary, where precipitation peaks during summer in association with the southernmost extension of the monsoon system. A second one is found over the central part of the basin, where precipitation peaks at different times in the seasonal cycle. Further analysis of the main tributaries of La Plata (Paran , Uruguay and Paraguay) reveals that each has a well defined annual cycle, but with different phases that can be traced primarily to each basin's physiography and precipitation regime. The upper and middle portions of the Paran River are most influenced by the summer monsoon regime, thus the river has a maximum discharge in late summer. The annual cycle of precipitation over the Uruguay River basin has two maxima, one in late autumn and the second one in spring and, consistently, the river discharge is largest in winter and spring. The smooth annual cycle of the Paraguay River discharge, with a maximum in winter, is the result of the Pantanal, a large wetland that

  5. Differences in the structure of copepod assemblages in four tropical estuaries: Importance of pollution and the estuary hydrodynamics.

    Science.gov (United States)

    Araujo, Adriana V; Dias, Cristina O; Bonecker, Sérgio L C

    2017-02-15

    We examined the relationship between pollution and structure of copepod assemblages in estuaries, using sampling standardization of salinity range to reduce the effects of "Estuarine Quality Paradox". Copepod assemblages were analyzed in four Southeast Brazilian estuaries with different water quality levels and different hydrodynamic characteristics. The pollution negatively impacted the descriptors of the assemblage structure. The distribution of structure of copepod assemblages also showed a main separation trend between the most polluted estuaries and those less polluted. Temperature was the main factor affecting the assemblage structuring in the four estuaries. This factor acted in synergism with the effects of pollution impact and physical characteristics of the estuaries on the structure of copepod assemblages, supporting the potential vulnerability of coastal environments due to nutrient enrichment associated with climate change. Our study demonstrated the importance of sampling standardization of the salinity range in estuaries for reliable analysis of pollution effects on biota. Copyright © 2016 Elsevier Ltd. All rights reserved.

  6. Construcción de electrodos de plata / cloruro de plata para medición de potenciales eléctricos en estructuras sumergidas

    OpenAIRE

    Alejandro David, Agama Mosquera; Peña Estrella, Julián

    2013-01-01

    En este proyecto se logró construir en el laboratorio de materiales un electrodo experimental plata/cloruro de plata para medición de potenciales eléctricos en estructuras sumergidas. Utilizando un procedimiento experimental llamado electrolisis se formo sobre el electrodo, específicamente en la rejilla del electrodo experimental una capa fina de cloruro de plata. A continuación se realizó los cálculos pertinentes de la masa de cloruro de plata que se formo durante el proceso de electrolisis ...

  7. Local Estuary Programs

    Science.gov (United States)

    This page provides information about Local Individual Estuary Programs including links to their NEP homepages, social media, Comprehensive Conservation and Management Plans, and state of the bay reports.

  8. Milwaukee Estuary AOC

    Science.gov (United States)

    The rivers in the Milwaukee estuary in Wisconsin drain into Lake Michigan. Wastewater treatment plants and combined sewer overflows contribute pollution which affects fish and wildlife and recreation.

  9. Management of Fishery Resources in Yangtze River Estuary

    OpenAIRE

    Li, Meiling; Huang, Shuolin

    2009-01-01

    We introduce the fish fauna composition and main commercial fishes in Yangtze River estuary. We also analyze the current situation of resources and environment in Yangtze River estuary as well as the influential factors. Finally, related countermeasures are put forward on how to protect and use the fishery resources in Yangtze River.

  10. A comparative study of Northern Ireland's estuaries based on the results of beam trawl fish surveys

    Science.gov (United States)

    Harrison, Trevor D.; Armour, Neil D.; McNeill, Michael T.; Moorehead, Peter W.

    2017-11-01

    The fish communities of Northern Ireland's estuaries were described and compared using data collected with a modified beam trawl over a six year period from 2009 to 2014. Multivariate analyses identified four estuary groups based on variations in their physico-chemical attributes. These groups broadly corresponded with the distribution and variation of estuary geomorphic types identified around the Irish coast. The dominant fish species captured were also among the main species reported in other North East Atlantic estuaries. A significant link between the estuary types and their fish communities was found; each estuary group contained a somewhat distinctive fish community. The fish communities also showed a significant relationship with the physico-chemical characteristics of the estuaries. Differences in fish species composition are attributed to habitat and environmental preferences of key estuary-associated species.

  11. The relationship between sediment and plutonium budgets in a small macrotidal estuary: Esk Estuary, Cumbria, UK

    International Nuclear Information System (INIS)

    Kelly, M.; Emptage, M.; Mudge, S.; Bradshaw, K.; Hamilton-Taylor, J.

    1991-01-01

    During a spring tide, measurements were made of sediment and 239,240 Pu discharges through a cross-section of the Esk estuary. These indicated that over the full tidal cycle, the inner estuary had a net gain of ca. 18 t of sediment and ca. 85 MBq of particulate phase 239,240 Pu, and a probable net loss of ca. 1 to 2 MBq of solution phase 239,240 Pu. Each of these was the net result of large gross discharges of sediment and plutonium into and out of the estuary for which the sea was the main source, with eroded estuarine sediment providing an additional minor source of sediment, of particulate phase plutonium and, via desorption, of solution phase plutonium. A net input with each tide, of sediment and its associated radionuclides, is considered to be typical for the Esk estuary under the normal conditions of low river flows. (author)

  12. Evaluation of sand reserves in del Plata City

    International Nuclear Information System (INIS)

    Loureiro, J.

    2014-01-01

    The purpose of this study is to evaluate the reserve of sand in the zone of del Plata city and beyond. This area is located in the S E edge of the department of San Jose near the mouth of Santa Lucia river. In this zone was identified the mantle of potentially exploitable sand which are based on their particle size, composition and depth of the limits cape. There are two powerful capes of sand separated by clay and silt

  13. Sedimentation Survey of Lago La Plata, Puerto Rico, July 2006

    Science.gov (United States)

    Soler-López, Luis R.

    2008-01-01

    Lago La Plata dam is located between the municipalities of Naranjito and Toa Alta in north central Puerto Rico, about 5 kilometers south of the town of Toa Alta and about 5 kilometers north of the town of Naranjito. The reservoir impounds the waters of the Rio de La Plata, the Rio Guadiana, and the Rio Ca?as, and is part of the San Juan Metropolitan Water District, which provides about 35 percent of the total water demand for the area (Soler-Lopez and others, 2000). The reservoir has a drainage area of about 469 square kilometers. The dam was constructed in 1974 and is a concrete gravity structure with a normal pool elevation of 52.00 meters above mean sea level (Puerto Rico Electric Power Authority, 1979). During October 1998, the U.S. Geological Survey (USGS), Caribbean Water Science Center, in cooperation with the Puerto Rico Aqueduct and Sewer Authority (PRASA) conducted a bathymetric survey of Lago La Plata to assess the impact of Hurricane Georges on the storage capacity of the reservoir. Between July 17 and 20, 2006, the USGS and the PRASA conducted an additional bathymetric survey of Lago La Plata to update the reservoir storage capacity and determine the reservoir sedimentation rate by comparing the 2006 survey data with the 1998 survey data.. The purpose of this report is to update the reservoir storage capacity, sedimentation rates, and areas of substantial sediment accumulation since 1998. Historical (1974) data are referenced as needed to account for long-term storage capacity loss trends...

  14. Recent La Plata basin drought conditions observed by satellite gravimetry

    OpenAIRE

    L. Chen , J.; R. Wilson , C.; D. Tapley , B.; Longuevergne , L.; L. Yang , Z.; R. Scanlon , B.

    2010-01-01

    International audience; The Gravity Recovery and Climate Experiment (GRACE) provides quantitative measures of terrestrial water storage (TWS) change. GRACE data show a significant decrease in TWS in the lower (southern) La Plata river basin of South America over the period 2002-2009, consistent with recognized drought conditions in the region. GRACE data reveal a detailed picture of temporal and spatial evolution of this severe drought event, which suggests that the drought began in lower La ...

  15. A numerical study of the Plata River plume along the southeastern South American continental shelf

    Directory of Open Access Journals (Sweden)

    Felipe M. Pimenta

    2005-12-01

    Full Text Available The Rio de la Plata, one of the largest rivers on Earth, discharges into the ocean waters from basin that covers a large area of South America. Its plume extends along northern Argentina, Uruguay, and southern Brazil shelves strongly influencing the ecosystems. In spite of this, little is known about the mechanisms that control it. Here we report results of simulations with POM carried out to investigate the roles of wind and river discharge in Plata plume dynamics. Different outflows were explored, including an average climatological value and magnitudes representative of La Niña and El Niño. Forcing the model with river discharge the average plume speed was directly related to the outflow intensity. The Plata northward extension varied from 850 to 1550 km and for average discharge a band of low salinity waters formed from the estuary up to 30ºN of South Brazilian Shelf. Upwelling and downwelling winds were applied after 130 days. The distribution of low salinity waters over the shelf was more sensitive to the wind direction than to the river outflow variability. Downwelling winds were very capable of advecting the low salinity signal downshelf. Upwelling winds were efficient in eroding the plume, which was basically detached from the coast by Ekman drift. Abnormal plume intrusions toward low latitudes may be a result of the original plume position coupled with events of persistent strong downwelling favorable winds.O Rio da Prata, um dos maiores rios da Terra, descarrega no oceano águas de uma bacia de drenagem que cobre uma ampla área da América do Sul. Sua pluma extende-se ao longo do norte da Argentina, Uruguay e sul do Brasil influenciando amplamente os ecossistemas costeiros. A despeito disso, pouco se sabe a respeito dos mecanismos que a controlam. Relatamos aqui simulações conduzidas com o modelo POM na investigação do papel dos ventos e da descarga fluvial na dinâmica da pluma do Prata. Descargas com valores médios climatol

  16. Vertisoles hidromórficos de la planicie costera del Río de La Plata, Argentina Hydromorphic vertisols of the Rio de La Plata coastal plain, Argentina

    Directory of Open Access Journals (Sweden)

    Perla Imbellone

    2011-12-01

    .Hydromorphic Vertisols are the dominant soils in the coastal plain of the la Plata river, Buenos Aires province, Argentina. Four repre-sentative soils in the districts of La Plata, Ensenada and Berazategui were studied. Pedological and sedimentological properties are described and analyzed. The purpose of this contribution is to discuss: a the grain size distribution and mineralogy of hydromorphic Vertisols in the rio de la Plata «mudflat»; b the influence of these properties on the generation of morphological features and c the associated pedogenic processes that take place. The morphology of the soil is related to vertic and hydromorphic features in the upper and middle horizons of the soil. Moderate and strong wedge-shaped and angular aggregates are abundant in the solum, with interpedal slickensides, sometimes striated, visible at various levels of observation. The matrix can be moderately or dominantly anisotropic and shows zones of optical anisotropism that run through the fine material with variegated patterns or anisotropic aureoles surrounding the pores. Hydromorphism is favoured by frequent pluvial flooding, the level landscape and the high water table, which is generally between 0.80 and 1.20 m deep. Therefore, endosa-turation or episaturation can occur at different times of the year. Soils have a variety of redoximorphic features, mainly reduced matrices (2.5Y, 5Y hues; chromas of 2 or less, redox concentrations of manganese and iron as nodules and concretions, surface impregnations of sesquioxides on the peds and some dark subsurface accumulations and ramifications through the matrix; there are also some depleted zones in the matrix. Concretions are hard in hand specimens and occur within the matrix; segregations are soft in hand specimens and they appear in thin sections as impregnations of the matrix with diffuse boundaries. They appear as mottles in the field. Soil textural class is clay. Fine clay markedly predominates over coarse clay. Soils are illitic Vertisols

  17. Conditions for tidal bore formation in convergent alluvial estuaries

    Science.gov (United States)

    Bonneton, Philippe; Filippini, Andrea Gilberto; Arpaia, Luca; Bonneton, Natalie; Ricchiuto, Mario

    2016-04-01

    Over the last decade there has been an increasing interest in tidal bore dynamics. However most studies have been focused on small-scale bore processes. The present paper describes the first quantitative study, at the estuary scale, of the conditions for tidal bore formation in convergent alluvial estuaries. When freshwater discharge and large-scale spatial variations of the estuary water depth can be neglected, tide propagation in such estuaries is controlled by three main dimensionless parameters: the nonlinearity parameter ε0 , the convergence ratio δ0 and the friction parameter ϕ0. In this paper we explore this dimensionless parameter space, in terms of tidal bore occurrence, from a database of 21 estuaries (8 tidal-bore estuaries and 13 non tidal-bore estuaries). The field data point out that tidal bores occur for convergence ratios close to the critical convergence δc. A new proposed definition of the friction parameter highlights a clear separation on the parameter plane (ϕ0,ε0) between tidal-bore estuaries and non tidal-bore estuaries. More specifically, we have established that tidal bores occur in convergent estuaries when the nonlinearity parameter is greater than a critical value, εc , which is an increasing function of the friction parameter ϕ0. This result has been confirmed by numerical simulations of the two-dimensional Saint Venant equations. The real-estuary observations and the numerical simulations also show that, contrary to what is generally assumed, tide amplification is not a necessary condition for tidal bore formation. The effect of freshwater discharge on tidal bore occurrence has been analyzed from the database acquired during three long-term campaigns carried out on the Gironde/Garonne estuary. We have shown that in the upper estuary the tidal bore intensity is mainly governed by the local dimensionless tide amplitude ε. The bore intensity is an increasing function of ε and this relationship does not depend on freshwater

  18. About Estuary Data Mapper (EDM)

    Science.gov (United States)

    Estuary Data Mapper is a tool for geospatial data discovery, visualization, and data download for any of the approximately 2,000 estuaries and associated watersheds in along the five US coastal regions.

  19. Determinantes de la morosidad tributaria en Mar del Plata

    OpenAIRE

    Mallo, Paulino E.; Artola, María Antonia; Zanfrillo, Alicia Inés; Morettini, Mariano; Galante, Marcelo Javier; Pascual, Mariano Enrique; Busetto, Adrián Raúl

    2011-01-01

    El objetivo del artículo es analizar, a través de la aplicación de lógica difusa y de herramientas estadísticas, el comportamiento de los indicadores contables de las PyMEs marplatenses, ya que los mismos pueden incidir en la determinación de la morosidad en el pago de tributos nacionales, provinciales o municipales. Para ello, se trabaja con una muestra de empresas representativas de distintos sectores productivos de la ciudad de Mar del Plata, que incluye organizaciones de distinto tamaño y...

  20. Nutrient budgets for large Chinese estuaries

    Directory of Open Access Journals (Sweden)

    S. M. Liu

    2009-10-01

    Full Text Available Chinese rivers deliver about 5–10% of global freshwater input and 15–20% of the global continental sediment to the world ocean. We report the riverine fluxes and concentrations of major nutrients (nitrogen, phosphorus, and silicon in the rivers of the contiguous landmass of China and Korea in the northeast Asia. The rivers are generally enriched with dissolved inorganic nitrogen (DIN and depleted in dissolved inorganic phosphate (PO43− with very high DIN: PO43− concentration ratios. DIN, phosphorus, and silicon levels and loads in rivers are mainly affected by agriculture activities and urbanization, anthropogenic activities and adsorption on particulates, and rock types, climate and physical denudation intensity, respectively. Nutrient transports by rivers in the summer are 3–4 times higher than those in the winter with the exception of NH4+. The flux of NH4+ is rather constant throughout the year due to the anthropogenic sources such as the sewer discharge. As nutrient composition has changed in the rivers, ecosystems in estuaries and coastal sea have also changed in recent decades. Among the changes, a shift of limiting nutrients from phosphorus to nitrogen for phytoplankton production with urbanization is noticeable and in some areas silicon becomes the limiting nutrient for diatom productivity. A simple steady-state mass-balance box model was employed to assess nutrient budgets in the estuaries. The major Chinese estuaries export <15% of nitrogen, <6% of phosphorus required for phytoplankton production and ~4% of silicon required for diatom growth in the Chinese Seas (Bohai, Yellow Sea, East China Sea, South China Sea. This suggests that land-derived nutrients are largely confined to the immediate estuaries, and ecosystem in the coastal sea beyond the estuaries is mainly supported by other nutrient sources such as regeneration, open ocean and

  1. Transformaciones territoriales en el periurbano de Mar del Plata

    Directory of Open Access Journals (Sweden)

    Laura Zulaica

    2012-01-01

    Full Text Available El estudio de las transformaciones territoriales de las áreas periurbanas demanda el conocimiento de la evolución de las actividades que allí se desarrollan. El presente trabajo analiza las transformaciones del periurbano de Mar del Plata entre los noventa y la actualidad, enfatizando en los cambios de las actividades. Para ello, se realiza una clasificación supervisada de usos sobre imágenes satelitales de 1989 y 2009, que es ajustada a partir de una base de datos del área. Posteriormente, se analizan las transformaciones considerando distintas fases de estructuración de las ciudades y se establece una periodización siguiendo las nociones de régimen y ruptura. El estudio realizado constituye una base para generar estrategias de ocupación y desarrollo del área y la metodología aplicada puede extenderse a otros territorios

  2. Los torques de plata de Monasterio de Rodilla

    Directory of Open Access Journals (Sweden)

    Castillo, Belén

    1996-12-01

    Full Text Available The silver torques coming from Monasterio de Rodilla (Burgos are an excepcional ensemble of the jewellery before Roman times in the northern Meseta. These pieces, wrought of rolled up braiding wires, belong to a fully-developed process in which the Iberian and Mediterranean influences become transformed by the local style and give rise to special and typical models of the Celtiberic jewellery.Los torques de plata procedentes de Monasterio de Rodilla (Burgos constituyen un conjunto excepcional de la orfebrería prerromana de la Meseta Norte. Estas piezas, elaboradas con alambres trenzados y enrollados, responden a un proceso evolucionado en el que las influencias ibéricas y mediterráneas, transformadas por el gusto local, dan lugar a modelos propios y característicos de la orfebrería celtibérica.

  3. The Mandovi and Zuari estuaries

    Digital Repository Service at National Institute of Oceanography (India)

    Shetye, S.R.; DileepKumar, M.; Shankar, D.

    of their extensive use for fisheries, agriculture, transportation, dumping of waste, etc. The two estuaries have since continued to attract scientific curiosity over the years, thanks in large measure to support from national and local funding agencies. As a... made so far to simulate them in numerical models, and characteristics of stratification and mixing. These are followed by chapters that examine the fun- damentals of biology and chemistry of the estuaries. A distinct characteristic of the estuaries...

  4. Ecology of estuaries

    International Nuclear Information System (INIS)

    Kennish, M.J.

    1992-01-01

    Ecology of Estuaries: Anthropogenic Effects represents the most definitive and comprehensive source of reference information available on the human impact on estuarine ecosystems. The book discusses both acute and insidious pollution problems plaguing these coastal ecotones. It also provides a detailed examination of the deleterious and pervasive effects of human activities on biotic communities and sensitive habitat areas in estuaries. Specific areas covered include organic loading, oil pollution, polynuclear aromatic hydrocarbons, chlorinated hydrocarbons, heavy metals, dredging and dredge-spoil disposal, radionuclides, as well as other contaminants and processes. The diverse components of these anthropogenic influences are assembled in an organized framework and presented in a clear and concise style that will facilitate their understanding

  5. Aquatic habitat modifications in La Plata River basin, Patagonia and associated marine areas.

    Science.gov (United States)

    Mugetti, Ana Cristina; Calcagno, Alberto Tomás; Brieva, Carlos Alberto; Giangiobbe, María Silvia; Pagani, Andrea; Gonzalez, Silvia

    2004-02-01

    This paper describes the environmental characteristics and situation of aquatic habitats and communities in southern continental and maritime areas of southeastern South America (Patagonian Shelf GIWA Subregion), resulting from an overall assessment carried out within the framework of a GIWA project, mostly on the basis of publicly available data. The main focus of the analysis was on the current situation of transboundary water resources and anthropogenic impacts. In the inland waters, habitat and community modifications result, principally, from dams and reservoirs built in the main watercourses for hydroelectric power generation and other uses. The transformation of lotic environments into lentic ones have affected habitats and altered biotic communities. In the La Plata River basin, invasive exotic species have displaced native ones. Habitats in the ocean have been degraded, as their biodiversity becomes affected by overfishing and pollution. This article includes a discussion on the causal chain and the policy options elaborated for the Coastal Ecosystem of Buenos Aires province and the Argentinean-Uruguayan Common Fishing Zone, where fishing resources are shared by both countries.

  6. La empleabilidad y los beneficiarios del Seguro de Capacitación y Empleo en Mar del Plata Employability and beneficiaries of the Training and Employment Insurance in Mar del Plata

    Directory of Open Access Journals (Sweden)

    Ana Julia Atucha

    2011-12-01

    , October 2009, by the Labour Studies Group, School of Economics and Social Sciences at the Universidad Nacional de Mar del Plata as part of a partnership with the ILO. The primary source was supplemented by telephone interviews with selected recipients. The approach was made through an exploration of educational paths followed by the recipients, their valuation about the improvement of their employability and the linking of labour market´s actors that the Office of Employment conducts. The main results reveal that there is a large proportion of beneficiaries without an educational paths that qualified them for an occupation, negative perceptions about their employability and situations of labor inactivity. The need for better job counseling and labor market attachment, in order to improve the situation of the analyzed group, is highlighted in this paper.

  7. Sediment Trapping in Estuaries

    Science.gov (United States)

    Burchard, Hans; Schuttelaars, Henk M.; Ralston, David K.

    2018-01-01

    Estuarine turbidity maxima (ETMs) are generated by a large suite of hydrodynamic and sediment dynamic processes, leading to longitudinal convergence of cross-sectionally integrated and tidally averaged transport of cohesive and noncohesive suspended particulate matter (SPM). The relative importance of these processes for SPM trapping varies substantially among estuaries depending on topography, fluvial and tidal forcing, and SPM composition. The high-frequency dynamics of ETMs are constrained by interactions with the low-frequency dynamics of the bottom pool of easily erodible sediments. Here, we use a transport decomposition to present processes that lead to convergent SPM transport, and review trapping mechanisms that lead to ETMs at the landward limit of the salt intrusion, in the freshwater zone, at topographic transitions, and by lateral processes within the cross section. We use model simulations of example estuaries to demonstrate the complex concurrence of ETM formation mechanisms. We also discuss how changes in SPM trapping mechanisms, often caused by direct human interference, can lead to the generation of hyperturbid estuaries.

  8. Biogeochemistry of the MAximum TURbidity Zone of Estuaries (MATURE): some conclusions

    NARCIS (Netherlands)

    Herman, P.M.J.; Heip, C.H.R.

    1999-01-01

    In this paper, we give a short overview of the activities and main results of the MAximum TURbidity Zone of Estuaries (MATURE) project. Three estuaries (Elbe, Schelde and Gironde) have been sampled intensively during a joint 1-week campaign in both 1993 and 1994. We introduce the publicly available

  9. Migration dynamics of clupeoids in the Schelde estuary: a stable isotope approach

    DEFF Research Database (Denmark)

    Guelinckx, J.; Maes, J.; De Brabandere, Loreto

    2006-01-01

    Large numbers of young of the year herring (Clupea harengus L.) and sprat (Sprattus sprattus (L.)) typically enter and remain within North Sea estuaries during the winter months. The main purpose of this study was to examine their migration dynamics between the North Sea and the Schelde estuary u...... is concluded the results support the hypothesis that migration to estuarine nurseries is individually based....

  10. Research, Monitoring, and Evaluation for the Federal Columbia River Estuary Program.

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Gary E.; Diefenderfer, Heida L. (Pacific Northwest National Laboratory)

    2008-02-20

    The purpose of this document is to describe research, monitoring, and evaluation (RME) for the Federal Columbia River Estuary Program, hereafter called 'the Estuary Program'. The intent of this RME effort is to provide data and information to evaluate progress toward meeting program goals and objectives and support decision making in the Estuary Program. The goal of the Estuary Program is to understand, conserve, and restore the estuary ecosystem to improve the performance of listed salmonid populations. The Estuary Program has five general objectives, designed to fulfill the program goal, as follows: (1) Understand the primary stressors affecting ecosystem controlling factors, such as ocean conditions and invasive species. (2) Conserve and restore factors controlling ecosystem structures and processes, such as hydrodynamics and water quality. (3) Increase the quantity and quality of ecosystem structures, i.e., habitats, juvenile salmonids use during migration through the estuary. (4) Maintain the food web to benefit salmonid performance. (5) Improve salmonid performance in terms of life history diversity, foraging success, growth, and survival. The goal of estuary RME is to provide pertinent and timely research and monitoring information to planners, implementers, and managers of the Estuary Program. The goal leads to three primary management questions pertaining to the main focus of the Estuary Program: estuary habitat conservation and restoration. (1) Are the estuary habitat actions achieving the expected biological and environmental performance targets? (2) Are the offsite habitat actions in the estuary improving juvenile salmonid performance and which actions are most effective at addressing the limiting factors preventing achievement of habitat, fish, or wildlife performance objectives? (3) What are the limiting factors or threats in the estuary/ocean preventing the achievement of desired habitat or fish performance objectives? Performance measures

  11. Prospects of approach and characterization of Mar del Plata peri-urban, Argentina

    Directory of Open Access Journals (Sweden)

    Rosana Ferraro

    2013-10-01

    Full Text Available In Latin America in general, and in Argentina in particular, city growth without prior planning results in the formation of highly complex peri-urban areas. The urban-rural analysis based on the traditional model of country-city dichotomy is not enough to explain the processes that occur in these cities. On the basis of prior studies conducted in the peri- urban of Mar del Plata, Argentina, this paper aims to : a characterize the peri-urban by studying its functions throughout history, b propose a rereading for its further analysis through the complex systems theoretical-methodological approach, and c describe the main areas that account for its special heterogeneity and complexity. From an integral viewpoint, and taking the physical, sociocultural, productive, urban- residential and digester subsystems into account, the analysis of the peri-urban allowed to define areas with differential characteristics. Such areas admit higher disintegration in more detailed scales, making it easy to understand their operation and their problems. In conclusion, the complex systems approach results appropriate to promote the development of management strategies in areas as heterogeneous as the peri-urban.

  12. Determination of risk indices in quarries of two basins in La Plata Municipality Argentina

    International Nuclear Information System (INIS)

    Cabral, M.; Crincoli, A.; Gimenez, J.; Hurtado, M.

    2004-01-01

    Soil extraction is one of the main causes of degradation of this resource in Buenos Aires province. In La Plata municipality, soil is extracted at different depths for a variety of uses. Deep soil extraction creates quarries which have a negative impact on the environment, the landscape, the real estate value and life quality. The inundated quarries become precarious swimming places where many people have drowned. When the quarries are used as garbage dumps, they can concentrate disease vectors or pollute groundwater through their leachates. The face-cuts are often near vertical and can be susceptible to collapse. The methodology to calculate the risk index is based on the hypothesis that risk variables can be identified, individually assessed and combined in such a way that they would provide a numerical value reflecting the likelihood of accidents or diseases occurring as a consequence of quarry's presence. The general objective of the project is to obtain an index for the quarries of the studied basins aimed at warning local authorities and affected persons about the sites where protection and reclamation measures are more urgently needed. The values obtained are represented on a map showing the risk class of each quarry. It is concluded that the methodology is useful to determine priorities and can prove a good management tool for those involved in this problem [es

  13. Linking behavior, physiology, and survival of Atlantic Salmon smolts during estuary migration

    Science.gov (United States)

    Stich, Daniel S.; Zydlewski, Gayle B.; Kocik, John F.; Zydlewski, Joseph D.

    2015-01-01

    Decreased marine survival is identified as a component driver of continued declines of Atlantic Salmon Salmo salar. However, estimates of marine mortality often incorporate loss incurred during estuary migration that may be mechanistically distinct from factors affecting marine mortality. We examined movements and survival of 941 smolts (141 wild and 800 hatchery-reared fish) released in freshwater during passage through the Penobscot River estuary, Maine, from 2005 to 2013. We related trends in estuary arrival date, movement rate, and survival to fish characteristics, migratory history, and environmental conditions in the estuary. Fish that experienced the warmest thermal history arrived in the estuary 8 d earlier than those experiencing the coolest thermal history during development. Estuary arrival date was 10 d later for fish experiencing high flow than for fish experiencing low flow. Fish released furthest upstream arrived in the estuary 3 d later than those stocked further downstream but moved 0.5 km/h faster through the estuary. Temporally, movement rate and survival in the estuary both peaked in mid-May. Spatially, movement rate and survival both decreased from freshwater to the ocean. Wild smolts arrived in the estuary later than hatchery fish, but we observed no change in movement rate or survival attributable to rearing history. Fish with the highest gill Na+, K+-ATPase activity incurred 25% lower mortality through the estuary than fish with the lowest gill Na+, K+-ATPase activity. Smolt survival decreased (by up to 40%) with the increasing number of dams passed (ranging from two to nine) during freshwater migration. These results underscore the importance of physiological preparedness on performance and the delayed, indirect effects of dams on survival of Atlantic Salmon smolts during estuary migration, ultimately affecting marine survival estimates.

  14. The Asamblea del Año XIII in the Rio de la Plata: Eternal Laurels to End the Revolution

    Directory of Open Access Journals (Sweden)

    Esteban Buch

    2016-09-01

    Full Text Available The Asamblea del año XIII, the 1813 Constitutional Assembly in the Río de la Plata, represents at its best revolutionary velocity, with its allegro rhythm towards wider liberties and a more perfect equality, towards an independence of the nation that, without being officially declared, inspires many of its gestures, like the creation of Argentina’s national anthem. A contemporary observer fond of anachronisms might find in it a confirmation that movement is an essential element of democracy. Yet, this dynamic perception should be balanced by reminding that the Assembly’s main project is not to accelerate the revolution, but to terminate it. “Close the period of the revolution, open the epoch of peace and freedom”, says its inaugural declaration. This paper focuses on the tension between these two conceptions of historical temporality.

  15. The vanguards and the passion for the real Anglo-Saxon Modernism in the Río de la Plata

    Directory of Open Access Journals (Sweden)

    Carina González

    2017-03-01

    Full Text Available The well-known returning of the real marked the beginning of a new revision that emphasizes the crisis of representation and the question of realism as a genre opened to an uncommon leaking. This returning must be rethinking by the reflection about how the avant-garde promotes the debate on aesthetics and politics. This essay proposes an approach to this topic by analyzing modernism as the avant-garde that introduces a third position in the dialectics of high art and popular culture, art and life or the individual and the world. The study of the work of Joyce and Kafka will be addressing by the traditional readings and its approaches from reviews and translations written by main authors in the Río de la Plata´s region.

  16. Impact of climate change on Gironde estuary

    International Nuclear Information System (INIS)

    Laborie, Vanessya; Hissel, Francois; Sergent, Philippe

    2014-01-01

    Within the THESEUS European project, a simplified mathematical model for storm surge levels in the Bay of Biscay was adjusted on 10 events at Le Verdon using wind and pressure fields from CLM/SGA, so that the water levels at Le Verdon have the same statistic quantiles as observed tide records for the period [1960-2000]. A numerical model of the Gironde Estuary was used to evaluate future water levels at 6 locations of the estuary from Le Verdon to Bordeaux and to assess the changes in the quantiles of water levels during the 21. century using ONERC's pessimistic scenario for sea level rise (60 cm). The analysis of future storm surge levels shows a decrease in their quantiles at Le Verdon,, whereas there is an increase of the quantiles of total water levels. This increase is smaller than the sea level rise and gets even smaller as one enters farther upstream in the estuary. A series of flood maps for different return periods between 2 and 100 years and for four time periods ([1960-1999], [2010-2039], [2040-2069] and [2070-2099]) have been built for the region of Bordeaux. Quantiles of water levels in the flood plain have also been calculated. The impact of climate change on the evolution of flooded areas in the Gironde Estuary and on quantiles of water levels in the flood plain mainly depends on the sea level rise. Areas which are not currently flooded for low return periods will be inundated in 2100. The influence of river discharges and dike breaching should also be taken into account for more accurate results. (authors)

  17. Anthropogenic Carbon Pump in an Urbanized Estuary

    Science.gov (United States)

    Park, J. H.; Yoon, T. K.; Jin, H.; Begum, M. S.

    2015-12-01

    The importance of estuaries as a carbon source has been increasingly recognized over the recent decades. However, constraining sources of CO2 evasion from urbanized estuaries remains incomplete, particularly in densely populated river systems receiving high loads of organic carbon from anthropogenic sources. To account for major factors regulating carbon fluxes the tidal reach of the Han River estuary along the metropolitan Seoul, characterization of organic carbon in the main stem and major urban tributaries were combined with continuous, submersible sensor measurements of pCO2 at a mid-channel location over a year and continuous underway measurements using a submersible sensor and two equilibrator sytems across the estuarine section receiving urban streams. Single-site continuous measurements exhibited large seasonal and diurnal variations in pCO2, ranging from sub-ambient air levels to exceptionally high values approaching 10,000 ppm. Diurnal variations of pCO2 were pronounced in summer and had an inverse relationship with dissolved oxygen, pointing to a potential role of day-time algal consumption of CO2. Cruise measurements displayed sharp pCO2 pulses along the confluences of urban streams as compared with relatively low values along the upper estuary receiving low-CO2 outflows from upstream dams. Large downstream increases in pCO2, concurrent with increases in DOC concentrations and fluorescence intensities indicative of microbially processed organic components, imply a translocation and subsequent dilution of CO2 carried by urban streams and/or fast transformations of labile C during transit along downstream reaches. The unique combination of spatial and temporal continuous measurements of pCO2 provide insights on estuarine CO2 pulses that might have resulted from the interplay between high loads of CO2 and organic C of anthropogenic origin and their priming effects on estuarine microbial processing of terrigenous and algal organic matter.

  18. Impact of climate change on Gironde Estuary

    Science.gov (United States)

    Laborie, Vanessya; Hissel, François; Sergent, Philippe

    2014-05-01

    Within the THESEUS European project, a simplified mathematical model for storm surge levels in the Bay of Biscay was adjusted on 10 events at Le Verdon using wind and pressure fields from CLM/SGA, so that the water levels at Le Verdon have the same statistic quantiles as observed tide records for the period [1960-2000]. The analysis of future storm surge levels shows a decrease in their quantiles at Le Verdon, whereas there is an increase of the quantiles of total water levels. This increase is smaller than the sea level rise and gets even smaller as one enters farther upstream in the estuary. A numerical model of the Gironde Estuary was then used to evaluate future water levels at 6 locations of the estuary from Le Verdon to Bordeaux and to assess the changes in the quantiles of water levels during the XXIst century using ONERC's pessimistic scenario for sea level rise (60 cm). The model was fed by several data sources : wind fields at Royan and Mérignac interpolated from the grid of the European Climatolologic Model CLM/SGA, a tide signal at Le Verdon, the discharges of Garonne (at La Réole), the Dordogne (at Pessac) and Isle (at Libourne). A series of flood maps for different return periods between 2 and 100 years and for four time periods ([1960-1999], [2010-2039], [2040-2069] and [2070-2099]) have been built for the region of Bordeaux. Quantiles of water levels in the floodplain have also been calculated. The impact of climate change on the evolution of flooded areas in the Gironde Estuary and on quantiles of water levels in the floodplain mainly depends on the sea level rise. Areas which are not currently flooded for low return periods will be inundated in 2100. The influence of river discharges and dike breaching should also be taken into account for more accurate results.

  19. Benthic survey of natural and artificial reefs off Mar del Plata, Argentina, southwestern Atlantic Estudios del bentos de arrecifes naturales y artificiales de Mar del Plata, Argentina, Atlántico sudoccidental

    Directory of Open Access Journals (Sweden)

    Gabriel Genzano

    2011-11-01

    Full Text Available This study describes the macrofaunal assemblages of subtidal rocky reefs off Mar del Plata in order to compare the macro invertebrate assemblages settled on shipwrecks with those of nearby reef sand to characterize the fish fauna associated with natural (NR and artificial (AR reefs. Topographic characterizations and surveys of invertebrates and fishes were performed in November and December 2005, using SCUBA diving. A non-parametric multivariate analysis was used to analyze the environmental and biological data. The reefs were mainly distinguished by their depth and the position of the substrate. The red calcareous algae, Corallina officinalis, dominated the shallowest NR, whereas conspicuous mytilid assemblages of Mytilus platensis were present at depths over 3 m, sea anemones, Anthothoe chilensis, were more abundant between 6 and 10 m, and the soft coral, Tripalea clavaria, was found at nearly 20 m depth. No differences were found between horizontal ARs and the adjacent NRs. The greatest differences were found between the communities of vertical and horizontal substrates, both in NRs and ARs. Fifteen fish species were recorded in the analyzed area. Species having strong site fidelity, e.g., Acanthistius brasilianus and Pseudopercis semifasciata, were clearly more abundant and/or frequent in ARs (shipwrecks than in NRs. This pioneer study in the surveyed area showed that reef sallow the settlement of diverse benthic assemblages. ARs also provide refuge for fishes. As sport fishing and diving are activities being carried out in Mar del Plata, where tourism is one of the main economic resources, the protection of such areas should be considered in conservation plans.Se describió la macrofauna de los arrecifes rocosos sublitorales, frente a Mar del Plata, para comparar las asociaciones de macro-invertebrados de los pecios con las de los arrecifes aledaños y caracterizar la fauna de peces tanto en los arrecifes naturales (NR como artificiales (AR

  20. NEW DATA ABOUT MACROZOOBENTHOS OF BEYSUGSKY ESTUARY (SEA OF AZOV

    Directory of Open Access Journals (Sweden)

    N. I. Bulysheva

    2013-01-01

    river network by the system of channels.Main conclusions. Major factors effecting composition, structure and distribution of benthic communities in the Beysug Estuary are: 1 bottom sediments’ structure (mostly clayey silts of pelite and, in certain parts, alevropelite fractions; 2 bathymetry of the water body (70 % of the estuary presented by 0,6–1 m depths, southern part of the estuary up to 2 m; 3 salinity, which varies from 6 ‰ in the east up to 10 ‰ in the west; 4 presence of macrophytes, solitarily occurring in the western part of the estuary.

  1. Morphodynamics, sedimentary and anthropogenic influences in the San Vicente de la Barquera estuary (North coast of Spain)

    OpenAIRE

    FLOR-BLANCO, G.; FLOR, G.; PANDO, L.; ABANADES, J.

    2015-01-01

    The estuary of San Vicente de la Barquera (Cantabria, Spain) occupies two fluvial valleys that have incised into soft sedimentary rocks (Lower Mesozoic) and are controlled by inactive faults. These two estuary subsystems, the Escudo (main valley) and Gandarilla, share outer estuarine zones, i.e., a sandy bay and an estuary-mouth complex. The complexity of the system lies in the presence of a confining barrier formed by an aeolian dune/ beach system that is currently enclosed by a jetty, which...

  2. Incidence of early-onset dementia in Mar del Plata.

    Science.gov (United States)

    Sanchez Abraham, M; Scharovsky, D; Romano, L M; Ayala, M; Aleman, A; Sottano, E; Etchepareborda, I; Colla Machado, C; García, M I; Gonorazky, S E

    2015-03-01

    Early-onset dementia (EOD) is defined as dementia with onset before the age of 65 years. EOD is increasingly recognised as an important clinical and social problem with devastating consequences for patients and caregivers. Determine the annual crude incidence rate and the specific incidence rates by sex and age in patients with EOD, and the standardised rate using the last national census of the population of Argentina (NCPA), from 2010. Hospital Privado de Comunidad, Mar del Plata, Argentina, attends a closed population and is the sole healthcare provider for 17 614 people. Using the database pertaining to the Geriatric Care department, we identified all patients diagnosed with EOD between 1 January, 2005 and 31 December, 2011. EOD was defined as dementia diagnosed in patients younger than 65. The study period yielded 14 patients diagnosed with EOD out of a total of 287 patients evaluated for memory concerns. The crude annual incidence of EOD was 11 per 100 000/year (CI 95%: 6.25-19.1): 17 per 100 000 (CI 95%: 7.2-33.1) in men and 8 per 100 000 (CI 95%: 3.4-17.2) in women. We observed a statistically significant increase when comparing incidence rates between patients aged 21 to <55 years and ≥ 55 to <65 years (3 vs 22 per 100 000, P=.0014). The rate adjusted by NCPA census data was 5.8 cases of EOD habitants/year. This study, conducted in a closed population, yielded an EOD incidence rate of 11 per 100 000 inhabitants/year. To the best of our knowledge, this is the first prospective epidemiological study in Argentina and in Latin America. Copyright © 2013 Sociedad Española de Neurología. Published by Elsevier Espana. All rights reserved.

  3. México en la Conferencia Económica Mundial de Londres: el Acuerdo de la Plata de 1933

    Directory of Open Access Journals (Sweden)

    Fabián Herrera León

    2010-12-01

    Full Text Available Pese a que a finales del mes de julio de 1933 la Conferencia Económica de Londres fue prácticamente clausurada al entrar en receso, México y otros países productores o usuarios de plata llegaron allí mismo a un acuerdo que ayudaría a equilibrar el mercado de la plata y elevar su precio. Sobre esta base, la política estadunidense de rescate del metal blanco estimulada poco tiempo después, aceleró la recuperación. Como ya ha sido destacado por la historiografía económica, los beneficios que obtuvo México del Acuerdo de Londres y del programa platista estadunidense contribuyeron sustancialmente a la expansión de su sistema monetario y al fortalecimiento de su banco central en el marco de la crisis. Sin embargo, se ha pasado por alto la cuidadosa e interesante actividad preparatoria del país para pugnar por este tipo de medidas, omisión que ha sido la principal motivación del autor en la realización de este artículo.Although the London Economic Conference (1933 was called off sine die at the end of July, Mexico and other silver producing and consuming countries came to an agreement that made possible to stabilize and increase the rate of this precious metal. As economic historiography has already emphasized, the benefits obtained by Mexico with the London Silver Agreement in 1933 favored both monetary system expansion and Central Bank strengthening during the crisis. Yet, the remarkable and cautious preparatory activity that Mexico fulfills to reach that goal has been neglected. This lack of information has prevented us to entirely understand this economic phenomenon and has been the author's main motivation while doing this paper.

  4. Trophic flow structure of a neotropical estuary in northeastern Brazil and the comparison of ecosystem model indicators of estuaries

    Science.gov (United States)

    Lira, Alex; Angelini, Ronaldo; Le Loc'h, François; Ménard, Frédéric; Lacerda, Carlos; Frédou, Thierry; Lucena Frédou, Flávia

    2018-06-01

    We developed an Ecopath model for the Estuary of Sirinhaém River (SIR), a small-sized system surrounded by mangroves, subject to high impact, mainly by the sugar cane and other farming industries in order to describe the food web structure and trophic interactions. In addition, we compared our findings with those of 20 available Ecopath estuarine models for tropical, subtropical and temperate regions, aiming to synthesize the knowledge on trophic dynamics and provide a comprehensive analysis of the structures and functioning of estuaries. Our model consisted of 25 compartments and its indicators were within the expected range for estuarine areas around the world. The average trophic transfer efficiency for the entire system was 11.8%, similar to the theoretical value of 10%. The Keystone Index and MTI (Mixed Trophic Impact) analysis indicated that the snook (Centropomus undecimalis and Centropomus parallelus) and jack (Caranx latus and Caranx hippos) are considered as key resources in the system, revealing their high impact in the food web. Both groups have a high ecological and commercial relevance, despite the unregulated fisheries. As result of the comparison of ecosystem model indicators in estuaries, differences in the ecosystem structure from the low latitude zones (tropical estuaries) to the high latitude zones (temperate system) were noticed. The structure of temperate and sub-tropical estuaries is based on high flows of detritus and export, while tropical systems have high biomass, respiration and consumption rates. Higher values of System Omnivory Index (SOI) and Overhead (SO) were observed in the tropical and subtropical estuaries, denoting a more complex food chain. Globally, none of the estuarine models were classified as fully mature ecosystems, although the tropical ecosystems were considered more mature than the subtropical and temperate ecosystems. This study is an important contribution to the trophic modeling of estuaries, which may also help

  5. Estuaries of the northeastern United States: Habitat and land use signatures

    Science.gov (United States)

    Roman, C.T.; Jaworski, N.; Short, F.T.; Findlay, S.; Warren, R.S.

    2000-01-01

    Geographic signatures are physical, chemical, biotic, and human-induced characteristics or processes that help define similar or unique features of estuaries along latitudinal or geographic gradients. Geomorphologically, estuaries of the northeastern U.S., from the Hudson River estuary and northward along the Gulf of Maine shoreline, are highly diverse because of a complex bedrock geology and glacial history. Back-barrier estuaries and lagoons occur within the northeast region, but the dominant type is the drowned-river valley, often with rocky shores. Tidal range and mean depth of northeast estuaries are generally greater when compared to estuaries of the more southern U.S. Atlantic coast and Gulf of Mexico. Because of small estuarine drainage basins, low riverine flows, a bedrock substrate, and dense forest cover, sediment loads in northeast estuaries are generally quite low and water clarity is high. Tidal marshes, seagrass meadows, intertidal mudflats, and rocky shores represent major habitat types that fringe northeast estuaries, supporting commercially-important fauna, forage nekton and benthos, and coastal bird communities, while also serving as links between deeper estuarine waters and habitats through detritus-based pathways. Regarding land use and water quality trends, portions of the northeast have a history of over a century of intense urbanization as reflected in increased total nitrogen and total phosphorus loadings to estuaries, with wastewater treatment facilities and atmospheric deposition being major sources. Agricultural inputs are relatively minor throughout the northeast, with relative importance increasing for coastal plain estuaries. Identifying geographic signatures provides an objective means for comparing the structure function, and processes of estuaries along latitudinal gradients.

  6. Suspended sediment dynamics in Cochin estuary, West coast, India

    Digital Repository Service at National Institute of Oceanography (India)

    Vinita, J.; Revichandran, C.; Manoj, N.T.

    concentration (SSC) were conducted at spring and neap periods of wet and dry seasons. These data were complemented by measurements of tides, currents, vertical profiling of hydrography and turbidity at the main inlet of the estuary. The results showed that SSC...

  7. Seasonal changes in suspended sediment load in the Gauthami-Godavari Estuary

    Digital Repository Service at National Institute of Oceanography (India)

    Reddy, N.P.C.; Rao, B.P.; Rao, K.M.; Rao, V.S.

    Studies carried out on suspended matter characteristics of the the Gautami Godavari Estuary revealed that the concentration of suspended matter (CSM) during southwest monsoon influenced mainly by the increased run off at both Neelarevu and Vrudha...

  8. Does boat traffic cause displacement of fish in estuaries?

    Science.gov (United States)

    Becker, Alistair; Whitfield, Alan K; Cowley, Paul D; Järnegren, Johanna; Næsje, Tor F

    2013-10-15

    Estuaries are increasingly under threat from a variety of human impacts. Recreational and commercial boat traffic in urban areas may represent a significant disturbance to fish populations and have particularly adverse effects in spatially restricted systems such as estuaries. We examined the effects of passing boats on the abundance of different sized fish within the main navigation channel of an estuary using high resolution sonar (DIDSON). Both the smallest (100-300 mm) and largest (>501 mm) size classes had no change in their abundance following the passage of boats. However, a decrease in abundance of mid-sized fish (301-500 mm) occurred following the passage of boats. This displacement may be attributed to a number of factors including noise, bubbles and the rapidly approaching object of the boat itself. In highly urbanised estuarine systems, regular displacement by boat traffic has the potential to have major negative population level effects on fish assemblages. Copyright © 2013 Elsevier Ltd. All rights reserved.

  9. Benthic communities on hard substrates covered by Limnoperna fortunei Dunker (Bivalvia, Mytilidae at an estuarine beach (Río de la Plata, Argentina

    Directory of Open Access Journals (Sweden)

    Fernando G. Spaccesi

    2012-01-01

    Full Text Available The structure and composition of benthic communities on hard substrates covered by the nonindigenous bivalve Limnoperna fortunei Dunker, the golden mussel, were quantified in the middle zone of the Río de la Plata Estuary (Argentina from April 2001 through March 2002. A total of 26 taxa were recorded. L. fortunei and Nematoda were the central and dominant groups, with a prodigious abundance of over 80%. The prevalence of L. fortunei, rather than the environmental variables, regulated the dynamics of the associated invertebrate fauna. The golden mussel alters both the structure and function of benthic native communities on hard substrates, allows a higher surface available for colonization and refuge, and provides food source to deposit-feeding organisms in the form of organic or residual material. The mussel also increases the abundance and diversity of taxa on hard substrata - such as Oligochaeta, Hirudinea, Tardigrada, Chironomidae, Copepoda, Tanaidacea, and Hydrachnidia. Similarities and nonparametric multidimensional-scaling analyses indicated that the benthic composition had a seasonal variation. L. fortunei has an environmental impact, an ability to invade new freshwater ambiences worldwide and ecological characteristic comparable to those of Dreissena polymorpha Pallas (the zebra mussel of North America and Europe.

  10. Estuary-wide genetic stock distribution and salmon habitat use, tidal-fluvial estuary - Columbia River Estuary Tidal Habitats

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The goal of the tidal-fluvial estuary study is to determine the estuary's contribution to the spatial structure and life history diversity of Columbia River salmon...

  11. Dynamics of intertidal flats in the Loire estuary

    Science.gov (United States)

    Kervella, Stephane; Sottolichio, Aldo; Bertier, Christine

    2014-05-01

    Tidal flats form at the edges of many tidal estuaries, and are found in broad climatic regions. Their evolution plays a fundamental role in maintaining the morphodynamic equilibrium of an estuary. The Loire estuary is one of the largest macrotidal systems of the french atlantic coast. Since 200 years, its geometry has been drastically modified through channeling, deepening, embanking, infilling of secondary channels, etc. These works altered many intertidal areas. In the recent years, efforts for the rectification of the morphology have been made in order to restore the ecology of the estuary. In this context, it is crucial to better understand the dynamics of intertidal flats, still poorly understood in this estuary. The aim of this work is to analyse a series of original observations conducted for the first time in two intertidal flats of the central Lore estuary between 2008 and 2010. The tidal flats are situated in the northern bank, at 12 and 17 km upstream from the mouth respectively. Six Altus altimeters were deployed at two cross shore transects, measuring continuously and at a high-frequency bed altimetry and water level, providing information on tide and waves. At the semi-diurnal tidal scale, the surficial sediment of intertidal flats is permanently mobilized. Altimetry variations are low, and their amplitude varies as a function of tides and river flow. At the scale of several months, the sedimentation is controlled by the position of the turbidity maximum (and therefore by the river flow) and also by the tidal amplitude. During low river flow periods, altimetry variations are only due to tidal cycles. During decaying tides, suspended sediment settle mainly on the lower part of the tidal flats, forming fluid mud layers of several cm thick, which can consolidate rapidly; under rising tides, the increasing of tidal currents promotes erosion. During periods of high river flow, the turbidity maximum shifts to the lower estuary. The higher suspended sediment

  12. Pesticide impact study in the peri-urban horticultural area of Gran La Plata, Argentina.

    Science.gov (United States)

    Mac Loughlin, Tomás M; Peluso, Leticia; Marino, Damián J G

    2017-11-15

    Vegetable production systems are characterized by intense pesticide use, yet the effects on the surrounding environment are largely unknown and need to be studied. Given this knowledge gap, the objective of this work is to determine the impact of horticulture on a representative watercourse by conducting an integrated study of the occurrence and concentration of pesticides in bottom sediments and their relation to lethal and sublethal effects on benthic fauna. Two sampling campaigns were conducted during seasons of low and high pesticide application in five sites along the Carnaval creek, located in the peri-urban area of La Plata City (Buenos Aires, Argentina). The samples were tested for 36 pesticide compounds by GC-MS and LC-MS, and whole-sediment laboratory toxicity tests were performed using the native amphipod Hyalella curvispina. The results showed a general but variable distribution in the concentrations detected along the stream. For each sampling campaign (first/second), the total pesticide loads, measured as the sum of herbicides, insecticides and fungicides, were 1080/2329, 3715/88, and 367/5ngg -1 dw, respectively. Lethal and sublethal effects were observed in both sampling campaigns. In order to correlate both sets of results, data were assessed by multivariate analysis, including principal component analysis. The observed toxicity was considered to be mainly due to insecticides; thus, horticultural practices have an impact on nearby watercourses and can potentially endanger the benthic fauna. This is the first study in Argentina to assess the impact of pesticides on aquatic environments close to horticultural production areas. Copyright © 2017 Elsevier B.V. All rights reserved.

  13. Rio de la Plata river: as paleoenvironmental focus using diatoms as proxies

    International Nuclear Information System (INIS)

    Perez, L; Garcia-Rodriguez, F; Hanebuth, T.

    2012-01-01

    The objective of this study is the reconstruction of the environmental history of the Rio de la Plata system in relation to the anthropogenic impact and historical changes in the flow with emphasis on salinity variations during the late Holocene. For this reason it was analyzed the composition of diatoms (grouped in freshwater (D), saline (S) and marine (M))

  14. Undergraduate education and training in optics at the Universidad Nacional de La Plata

    Science.gov (United States)

    Garavaglia, Mario

    2000-06-01

    After few historical and statistical data related to the Universidad Nacional de La Plata, follows a description of activities on undergraduate training in Optics at the Laboratorio de Optica, belonging to the Faculty of Astronomical and Geophysical Sciences, and on undergraduate education in Optics at the Departamento de Fisica, belonging to the Faculty of Exact Sciences.

  15. Occurrence of Microcystis aeruginosa and microcystins in Río de la Plata river (Argentina

    Directory of Open Access Journals (Sweden)

    Darío Andrinolo

    2007-07-01

    Full Text Available This paper is the first report on microcystins producer blooms of Microcystis aeruginosa in the Argentinean coast of the Río de la Plata river, the most important drinking water supply of Argentina. The distribution of toxic cyanobacterium Microcystis cf. aeruginosa blooms in the Argentinean coast of the Rio de la Plata river was studied from December 2003 and January 2006. Microcystis aeruginosa persisted in the river with values ranged between 0 - 7.8 10(4 cells ml-1. Samples of two Microcystis aeruginosa water blooms were collected at La Plata river and were analyzed by the mouse bioassay and by high-performance liquid chromatography with Diode-array and MS detector. The samples showed high hepatotoxicity in mouse bioassay and, in accordance, important amount of microcystins. The bloom samples contained microcystins LR and a variant of microcystin with a molecular ion [M+H]+= 1037.8 m/z as major components. The total toxin content found in these samples was 0.94μg/mg and 0.69μg/mg of lyophilised cells. We conclude that the presence of toxic clones of Microcystis aeruginosa in the Argentinean coast of the Río de la Plata is an actual sanitary and environmental problem and that further studies are necessary to make the risk assessment.

  16. 75 FR 34975 - Notice of Estuary Habitat Restoration Council's Intent to Revise its Estuary Habitat Restoration...

    Science.gov (United States)

    2010-06-21

    ... Estuary Habitat Restoration Council's Intent to Revise its Estuary Habitat Restoration Strategy; Request... interagency Estuary Habitat Restoration Council, is providing notice of the Council's intent to revise the ''Estuary Habitat Restoration Strategy'' and requesting public comments to guide its revision. DATES...

  17. Analysis of Current and Future SPEI Droughts in the La Plata Basin Based on Results from the Regional Eta Climate Model

    Directory of Open Access Journals (Sweden)

    Alvaro Sordo-Ward

    2017-11-01

    Full Text Available We identified and analysed droughts in the La Plata Basin (divided into seven sub-basins for the current period (1961–2005 and estimated their expected evolution under future climate projections for the periods 2011–2040, 2041–2070, and 2071–2099. Future climate projections were analysed from results of the Eta Regional Climate Model (grid resolution of approximately 10 km forced by the global climate model HadGEM2-ES over the La Plata basin, and considering a RCP4.5 emission scenario. Within each sub-basin, we particularly focused our drought analyses on croplands and grasslands, due to their economic relevance. The three-month Standardized Precipitation Evapotranspiration Index (SPEI3 was used for drought identification and characterization. Droughts were evaluated in terms of time (percentage of time from the total length of each climate scenario, space (percentage of total area, and severity (SPEI3 values of cells characterized by cropland and grassland for each sub-basin and climate scenario. Drought-severity–area–frequency curves were developed to quantitatively relate the frequency distribution of drought occurrence to drought severity and area. For the period 2011–2040, droughts dominate the northern sub-basins, whereas alternating wet and short dry periods dominate the southern sub-basins. Wet climate spread from south to north within the La Plata Basin as more distant future scenarios were analysed, due to both a greater number of wet periods and fewer droughts. The area of each sub-basin affected by drought in all climate scenarios was highly varied temporally and spatially. The likelihood of the occurrence of droughts differed significantly between the studied cover types in the Lower Paraguay sub-basin, being higher for cropland than for grassland. Mainly in the Upper Paraguay and in the Upper Paraná basins the climate projections for all scenarios showed an increase of moderate and severe droughts over large regions

  18. Frequent Questions about Estuary Data Mapper (EDM)

    Science.gov (United States)

    Estuary Data Mapper is a tool for geospatial data discovery, visualization, and data download for any of the approximately 2,000 estuaries and associated watersheds in along the five US coastal regions

  19. Downloading and Installing Estuary Data Mapper (EDM)

    Science.gov (United States)

    Estuary Data Mapper is a tool for geospatial data discovery, visualization, and data download for any of the approximately 2,000 estuaries and associated watersheds in along the five US coastal regions

  20. Influence of estuaries on shelf foraminiferal species

    Digital Repository Service at National Institute of Oceanography (India)

    Nigam, R.

    Dabhol-bhatkal stretch of the west coast of India is marked by a number of estuaries. Cavarotalia annectens is selected to monitor the influence of these estuaries on the inner shelf foraminiferal fauna. The percentage distribution of this species...

  1. SANCOR estuaries programme 1982-1986

    CSIR Research Space (South Africa)

    SANCOR

    1983-02-01

    Full Text Available , such research will also aid in the rational management of estuaries. Estuaries on which research should be concentrated are identified and guidelines are given for project proposals and reporting....

  2. Nutrients in some estuaries of Kerala

    Digital Repository Service at National Institute of Oceanography (India)

    Devi, K.S.; Venugopal, P.; Remani, K.N.; Zacharias, D.; Unnithan, R.V.

    phosphate and ammonia were high at Kallai compared to other three estuaries. All the estuaries showed an increase in nitrate content during monsoon. Nitrite values were high in postmonsoon. Ammonia levels were generally high except at Korapuzha. Nutrient...

  3. Ostracoda and foraminifera as short-term tracers of environmental changes in very polluted areas: the Odiel Estuary (SW Spain)

    International Nuclear Information System (INIS)

    Ruiz, F.; Gonzalez-Regalado, M.L.; Borrego, J.; Abad, M.; Pendon, J.G.

    2004-01-01

    The analysis of 17 cores collected in the Odiel Estuary (SW Spain) permits delimiting the recent evolution of this zone during the past decades and the influence of natural and anthropogenic factors on the distribution of Ostracoda and Foraminifera. In the upper estuary, the coincidence of acid waters, prolonged subaerial exposure, and coarse sediments may explain the absence or the disappearance of these microorganisms during the industrial period (1966-1985) in the major part of this area. In the lower estuary, sedimentary evolution and industrial wastes are the main factors influencing both the distribution and trends of the populations of these two groups. Finally, the main changes observed in the marine estuary are due to the sedimentary effects of the construction of two banks and the dredging of the main estuarine channel. - In a polluted estuary, the meiofaunal assemblages experience different changes even in adjacent sedimentary environments, closely related to anthropogenic and natural causes

  4. Leven estuary project. Fisheries Department final report

    OpenAIRE

    Bayliss, B.D.

    1997-01-01

    This is the report on the Leven estuary project: Fisheries Department final report produced by the Environment Agency North West in 1997. This report contains information about Leven estuary, river Leven catchment, river Crake catchment and the Ulverston Discharges. The Leven estuary is characterised by being very shallow, and shares the extremely variable tides and currents that characterize the whole of Morecambe Bay. There was little detailed knowledge of the impact on the Leven estuary, a...

  5. A numerical study of local variations in tidal regime of Tagus estuary, Portugal.

    Science.gov (United States)

    Dias, João Miguel; Valentim, Juliana Marques; Sousa, Magda Catarina

    2013-01-01

    Tidal dynamics of shallow estuaries and lagoons is a complex matter that has attracted the attention of a large number of researchers over the last few decades. The main purpose of the present work is to study the intricate tidal dynamics of the Tagus estuary, which states as the largest estuary of the Iberian Peninsula and one of the most important wetlands in Portugal and Europe. Tagus has large areas of low depth and a remarkable geomorphology, both determining the complex propagation of tidal waves along the estuary of unknown manner. A non-linear two-dimensional vertically integrated hydrodynamic model was considered to be adequate to simulate its hydrodynamics and an application developed from the SIMSYS2D model was applied to study the tidal propagation along the estuary. The implementation and calibration of this model revealed its accuracy to predict tidal properties along the entire system. Several model runs enabled the analysis of the local variations in tidal dynamics, through the interpretation of amplitude and phase patterns of the main tidal constituents, tidal asymmetry, tidal ellipses, form factor and tidal dissipation. Results show that Tagus estuary tidal dynamics is extremely dependent on an estuarine resonance mode for the semi-diurnal constituents that induce important tidal characteristics. Besides, the estuarine coastline features and topography determines the changes in tidal propagation along the estuary, which therefore result essentially from a balance between convergence/divergence and friction and advection effects, besides the resonance effects.

  6. Indian estuaries: Dynamics, ecosystems, and threats

    Digital Repository Service at National Institute of Oceanography (India)

    Shetye, S.R.

    the tide pulls the mixed water out of the estuary through its mouth. Different processes within an estuary contribute to mixing of the two waters, the important among these in the Mandovi estuary are: influence of the tide on the advective field within...

  7. Monitoring requirements for detecting tidal barrage induced changes to estuary bird populations

    International Nuclear Information System (INIS)

    Davenport, T.; Jeffers, J.N.R.; North, P.M.; Clark, N.A.; Langston, R.H.W.; Prys-Jones, R.P.

    1990-01-01

    This study was performed to examine the monitoring requirements for detecting tidal barrage induced changes to estuary bird populations, focussing mainly on the Mersey estuary. The degree of variability in populations between years for a number of species within the Mersey, Dee, Alt and Ribble were ascertained. The number of counts needed each winter, before and after barrage construction, were assessed. The percentage charge detectable for species was predicted. One east coast estuary (the Wash) was investigated for comparison of the effects of influences of severe weather. (UK)

  8. Numerical modelling of tidal circulation and studies on salinity distribution in Mandovi and Zuari estuaries

    Digital Repository Service at National Institute of Oceanography (India)

    Manoj, N.T.

    the characteris- tics of tidal propagation and salinity distribution in the Mandovi and Zuari estuaries using a hybrid network numerical model. One of the main objective was to study the longi- tudinal variation of tides during dry and wet seasons and freshwater... of the Zuari and Mandovi estuaries in relation to tides. Proceedings of the Indian Academy of Sciences, 72:68–80, 1970. P. V. Dehadrai and R. M. S. Bhargava. Seasonal organic production in relation to en- vironmental features in Mandovi and Zuari estuaries, Goa...

  9. Establishment of a non-governmental regional approach to La Plata River Basin integrated watershed management promoted throughout three international workshops supported by UN and Japanese agencies, led by ILEC

    Science.gov (United States)

    Calcagno, Alberto; Yamashiki, Yosuke; Mugetti, Ana

    2002-08-01

    The La Plata River Basin is one of the largest international river basins in the world, with an area of about 3 million km2. It spreads across five countries (Argentina, Bolivia, Brazil, Paraguay and Uruguay), and its water resources are essential for their economic development. Together with reservoir development, extensive deforestation, intensive agriculture practices and large urban developments took place in the Paraná, Paraguay and Uruguay basins, affecting environmental conditions and raising important issues concerning water resources use and conservation. Therefore, the need to promote participatory and cooperative efforts among water resources stakeholders, as well as the systematic exchange of information and experiences on common regional problems among organizations and experts from throughout the basin who are devoted to water resources use and management, was reported by researchers and managers gathered at the First and Second International Workshops on Regional Approaches for Reservoir Development and Management in the La Plata River Basin (held in 1991 and 1994). As a concrete response to this need, the efforts of a number of organizations from various countries within the basin, with the support of international and national governmental organizations, resulted in the foundation of La Plata River Basin Environmental Research and Management Network (RIGA) in March 2001. This was within the framework of the Third International Workshop, which was precisely one of the short-term activities included in the RIGA Action Plan. During the preparatory processes for the RIGA Network, the presence of Japanese cooperation supporting the La Plata River Basin Workshops through a non-governmental international organization (ILEC) played an important role in stimulating such an organization-based joint approach in the basin. This outcome, although not originally planned, constituted a welcomed byproduct of its main specific interest in the region, which was the

  10. Influencia de la temperatura en la fijación y penetración de la plata durante la lixiviación de calcopirita con microorganismos termófilos moderados

    Directory of Open Access Journals (Sweden)

    Cancho, L.

    2004-06-01

    Full Text Available Bioleaching of chalcopyrite using mesophilic microorganisms considerably improves in the presence of silver. However, the studies carried out with moderate thermophilic microorganisms do not show a significant improvement with regard to the use of mesophilic bacteria. The main objective of the present work has been to study the silver fixation on chalcopyrite at 35 and 45 °C and its influence on the microbiological attack. Different observations using SEM, EDS microanalysis and concentration profiles using electron microprobe have been carried out. The study of the different samples showed that silver fixation was more favourable at 35 °C than at 45 °C. In addition, bacterial action improved silver penetration through attack cracks.

    La biolixiviación de la calcopirita con microorganismos mesófilos mejora considerablemente cuando se utiliza plata en el medio de reacción. Sin embargo, los estudios realizados con microorganismos termófilos moderados no muestran una mejora significativa con respecto a la utilización de bacterias mesófilas. El objetivo del presente trabajo ha sido el estudio de la fijación de plata sobre calcopirita a 35 y 45 °C y su influencia en el ataque microbiológico. Se han realizado observaciones con SEM, microanálisis por EDS y perfiles de concentración con microsonda electrónica. El estudio de las distintas muestras reveló que la fijación de la plata fue más favorable a 35 que a 45 °C y que la acción bacteriana favoreció la penetración de la plata a través de las grietas de ataque.

  11. The student movement at the Universidad Nacional de La Plata before the "Revolución Libertadora": actors, transformations and conflicts between September, 1955 and May 1956

    Directory of Open Access Journals (Sweden)

    Nayla Pis Diez

    2016-07-01

    Full Text Available In this paper we intend to approach the events that marked the institutional and political dynamics of the Universidad Nacional de La Plata (UNLP between the months of September 1955 and May 1956, with special emphasis on the student movement. We'll use written sources as documentary material to revisit the first months of the postperonist UNLP, taking into account three aspects of the ongoing process: in the first place, the process of reconstruction and desperonización of university structures, teachers and administration. In second place, we explore which was the role of the student movement: what actions it carried out, which were the internal differences and the main debates. As is known, the process of university normalization went through a disruptive moment beginning 1956: the enactment of the decree-law no. 6.403, and in particular its article no. 28, would cause massive mobilizations (both in its favor and against, numerous outlets and even strong incidents in La Plata streets. The last lines of the work will be devoted to this third aspect of the indicated period

  12. Factors governing the pH in a heterotrophic, turbid, tidal estuary

    Science.gov (United States)

    Hofmann, A. F.; Meysman, F. J. R.; Soetaert, K.; Middelburg, J. J.

    2009-01-01

    A method to quantify the influence of kinetically modelled biogeochemical processes on the pH of an ecosystem with time variable acid-base dissociation constants is presented and applied to the heterotrophic, turbid Scheldt estuary (SW Netherlands, N Belgium). Nitrification is identified as the main process governing the pH profile of this estuary, while CO2 degassing and advective-dispersive transport "buffer" the effect of nitrification. CO2 degassing accounts for the largest proton turnover per year in the whole estuary. There is a clear inverse correlation between oxygen turnover and proton turnover. The main driver of long-term changes in the mean estuarine pH from 2001 to 2004 is a changing freshwater flow which influences the pH "directly" via [∑CO2] and [TA] and to a significant amount also "indirectly" via [∑NH4+] and the nitrification rates in the estuary.

  13. Mercury distribution in Douro estuary (Portugal)

    Energy Technology Data Exchange (ETDEWEB)

    Ramalhosa, E. [Department of Chemistry, University of Aveiro, 3810-193 Aveiro (Portugal); Pereira, E. [Department of Chemistry, University of Aveiro, 3810-193 Aveiro (Portugal)]. E-mail: eduper@dq.ua.pt; Vale, C. [National Institute for Agronomy and Fishery Research, IPIMAR, Avenida Brasilia, 1449-006 Lisboa (Portugal); Valega, M. [Department of Chemistry, University of Aveiro, 3810-193 Aveiro (Portugal); Monterroso, P. [Department of Chemistry, University of Aveiro, 3810-193 Aveiro (Portugal); Duarte, A.C. [Department of Chemistry, University of Aveiro, 3810-193 Aveiro (Portugal)

    2005-11-15

    Determinations of dissolved reactive and total dissolved mercury, particulate and sedimentary mercury, dissolved organic carbon (DOC), particulate organic carbon (POC) and suspended particulate matter (SPM) have been made in the estuary of river Douro, in northern Portugal. The estuary was stratified by salinity along most of its length, it had low concentrations of SPM, typically <20 mg dm{sup -3}, and concentrations of DOC in the range <1.0-1.8 mg dm{sup -3}. The surface waters had a maximum dissolved concentration of reactive mercury of about 10 ng dm{sup -3}, whereas for the more saline bottom waters it was about 65 ng dm{sup -3}. The surface waters had maximum concentrations of total suspended particulate mercury of {approx}7 {mu}g g{sup -1} and the bottom waters were always <1 {mu}g g{sup -1}. Concentrations of mercury in sediments was low and in the range from 0.06 to 0.18 {mu}g g{sup -1}. The transport of mercury in surface waters was mainly associated with organic-rich particulate matter, while in bottom waters the dissolved phase transport of mercury is more important. Lower particulate organic matter, formation of chlorocomplexes in more saline waters and eventually the presence of colloids appear to explain the difference of mercury partitioning in Douro estuarine waters.

  14. Seasonal and interannual variability of mesozooplankton in two contrasting estuaries of the Bay of Biscay: Relationship to environmental factors

    Science.gov (United States)

    Villate, Fernando; Iriarte, Arantza; Uriarte, Ibon; Sanchez, Iraide

    2017-12-01

    Seasonal and interannual variations of total mesozooplankton abundance and community variability were assessed for the period 1998-2005 at 3 salinity sites (35, 33 and 30) of the estuaries of Bilbao and Urdaibai (southeast Bay of Biscay). Spatial differences in mesozooplankton seasonality were recognized, both within and between estuaries, related to differences between sites in hydrodynamic features and anthropogenic nutrient enrichment that drive phytoplankton biomass seasonal cycles. The within estuary seasonal differences in mesozooplankton community were mainly shown through seaward time-advances in the seasonal peak from summer to spring along the salinity gradient, linked to differences in phytoplankton availability during the summer, in turn, related to nutrient availability. These differences were most marked in the estuary of Urdaibai, where zooplankton seasonal pattern at 35 salinity (high tidal flushing) resembled that of shelf waters, while at 35 of the estuary of Bilbao zooplankton showed an estuarine seasonal pattern due to the influence of the estuarine plume. Cirripede larvae contributed most to the mesozooplankton seasonal variability, except at the outer estuary of Bilbao, where cladocerans and fish eggs and larvae were the major contributors, and the inner estuary of Urdaibai, where gastropod larvae contributed most. Total mesozooplankton increased at 30 salinity of the estuary of Bilbao and 35 salinity of the estuary of Urdaibai. Interannual variability of mesozooplankton at the lowest salinity of the estuary of Bilbao was mainly accounted for by copepods due to the introduction of non-indigenous species during estuarine rehabilitation from intense pollution. However, bivalve larvae and gastropod larvae showed the highest contributions at 35 salinity of the estuary of Urdaibai. At the rest of sites, the opposite interannual trends of polychaete larvae and hydromedusae generally made the highest contribution.

  15. Long-term changes in primary production and mineralization of organic matter in the Neva Estuary (Baltic Sea)

    Science.gov (United States)

    Golubkov, Sergey; Golubkov, Mikhail; Tiunov, Alexei; Nikulina, Vera

    2017-07-01

    The Neva Estuary situated in the eastern part of the Gulf of Finland is one of the largest estuaries of the Baltic Sea. At present, heavy nutrient and organic matter loading, mainly from the Neva River and point sources in the upper estuary are the most serious environmental problem for the Neva Estuary and adjacent parts of the eastern Gulf of Finland. Long-term studies of mid-summer primary production and mineralization of organic matter were conducted in upper and middle parts of the Neva Estuary. A considerable increase of production and biomass of phytoplankton was observed in the middle part of the estuary during the last decades mainly due to an increase in biomass of cyanobacteria. However, they are mostly concentrated in the upper water layers and only a small part of them reached the near bottom water layers and may be used as a food by zoobenthos. The mineralization of organic matter in the water column was twice higher than primary production that indicates the importance of allochthonous organic matter in the carbon budget of the both parts of the estuary. The carbon isotope signature of seston and most of the zoobenthic species in the upper part of the estuary was close to the signature of allochthonous carbon leaking from watershed (- 27‰). Higher values of δ13C of seston in the upper mix layer of the Middle estuary indicate intensive primary production in mid-summer. The carbon isotopic signature of zoobenthos in this part of the estuary was also in general lower than in the Neva Bay reflected higher importance of autochthonous organic matter in food webs of the estuary.

  16. Pu and 137Cs in the Yangtze River estuary sediments: distribution and source identification.

    Science.gov (United States)

    Liu, Zhiyong; Zheng, Jian; Pan, Shaoming; Dong, Wei; Yamada, Masatoshi; Aono, Tatsuo; Guo, Qiuju

    2011-03-01

    Pu isotopes and (137)Cs were analyzed using sector field ICP-MS and γ spectrometry, respectively, in surface sediment and core sediment samples from the Yangtze River estuary. (239+240)Pu activity and (240)Pu/(239)Pu atom ratios (>0.18) shows a generally increasing trend from land to sea and from north to south in the estuary. This spatial distribution pattern indicates that the Pacific Proving Grounds (PPG) source Pu transported by ocean currents was intensively scavenged into the suspended sediment under favorable conditions, and mixed with riverine sediment as the water circulated in the estuary. This process is the main control for the distribution of Pu in the estuary. Moreover, Pu is also an important indicator for monitoring the changes of environmental radioactivity in the estuary as the river basin is currently the site of extensive human activities and the sea level is rising because of global climate changes. For core sediment samples the maximum peak of (239+240)Pu activity was observed at a depth of 172 cm. The sedimentation rate was estimated on the basis of the Pu maximum deposition peak in 1963-1964 to be 4.1 cm/a. The contributions of the PPG close-in fallout Pu (44%) and the riverine Pu (45%) in Yangtze River estuary sediments are equally important for the total Pu deposition in the estuary, which challenges the current hypothesis that the riverine Pu input was the major source of Pu budget in this area.

  17. Carbon budgets for two Portuguese estuaries: implications for the management and conservation of coastal waters

    Directory of Open Access Journals (Sweden)

    Ana P. Oliveira

    2014-07-01

    The results presented illustrate that Tagus and Sado estuaries represent an important land/ocean boundary for carbon transformation and emission, and confirm the anthropogenic pressure that these estuaries are subject to. Carbon budgets vary markedly within and between these two estuaries reflecting the human pressure. Anthropogenic inputs, autochthonous carbon production and primary production are indicated as the main responsible for the carbon production within the estuaries. Both estuaries export carbon to the ocean and to the atmosphere. The inorganic carbon faction has a major role in the carbon budget, enriching the ocean in carbon dioxide, contributing this for the greenhouse effect. Our understanding of organic and inorganic carbon fluxes in Tagus and Sado estuaries is vital for an efficient protection and preservation of such ecosystems being helpful in limit human-caused damage and in restoring damaged estuarine/coastal ecosystems. In addition, the economic impact of the carbon fluxes to the atmosphere, estimated as €375,000 per year, creates the appropriate incentives to reduce emissions and shift them to higher-value uses. Suggesting, therefore, a coastal management re-oriented towards a more adaptive approach through the use of carbon market-based policies. This study is a contribution to the integration of coastal and global carbon cycles. However, additional efforts are required to fully merge other components subsystems, such as salt marshes, with these budgets. Moreover, a fully comprehension of the community metabolism in these estuaries will greatly improve this integration.

  18. Biogeochemical budgets for Tapi Estuary

    Digital Repository Service at National Institute of Oceanography (India)

    Bapardekar, M.V.; DeSousa, S.N.; Zingde, M.D.

    sup(-1) comes from the wastes. Chemical fertilizers are used in the basin at the rate of 113 kg.ha sup(-1). During the dry season the salinity in the estuary decreases progressively in the upstream direction form an average 32.53 psu at the mouth to 0...

  19. Food Webs in an Estuary.

    Science.gov (United States)

    Dunne, Barbara B.

    The Maryland Marine Science Education Project has produced a series of mini-units in marine science education for the junior high/middle school classroom. This unit focuses on food chains in an estuary. Although the unit specifically treats the Chesapeake Bay, it may be adapted for use with similar estuarine systems. In addition, the unit may be…

  20. Simulated Sampling of Estuary Plankton

    Science.gov (United States)

    Fortner, Rosanne W.; Jenkins, Deborah Bainer

    2009-01-01

    To find out about the microscopic life in the valuable estuary environment, it is usually necessary to be near the water. This dry lab offers an alternative, using authentic data and a simulation of plankton sampling. From the types of organisms found in the sample, middle school students can infer relationships in the biological and physical…

  1. Environmental features and macrofauna of Kahana Estuary, Oahu, Hawaii

    Science.gov (United States)

    Maciolek, J.A.; Timbol, A.S.

    1981-01-01

    Lack of ecological information on Hawaiian estuaries prompted an intensive 2-year study of a small (5.7 ha) stream-mouth estuary on windward Oahu. Water quality and macrofauna were sampled weekly at seven stations. The water mass was strongly stratified vertically except during freshets. Average values for water column temperature and bottom salinity were 23.2°C and 12‰ at the head to 28.3°C and 28‰ at the mouth. Dissolved oxygen saturation in the water column varied from about 50% at night to 140% in the afternoon. Usually, bottom waters were 3–6°C warmer than surface waters and sometimes showed severe oxygen depletion.Macrofauna, collected primarily by seining, consisted mainly of decapod crustaceans (four species of crabs, seven species of shrimps) and fishes (24 species). Other typical estuarine taxons (mollusks, barnacles, polychaetes) were scarce or absent. Diversity increased seaward from 14 species near the estuary head to 29 species near the mouth. Three species of crustaceans and six of fishes were captured at all stations. Most abundant were the native prawn, Macrobrachium grandimanus, and mullet, Mugil cephalus. Perennially resident adults occurred among crustaceans and gobioid fishes; most other fishes were present as juveniles and sporadic adults. Comparisons with other data suggest that more than 50 species of native fishes may occur in Hawaiian estuaries, and that estuarine macrofaunal diversity on oceanic islands is much lower than on continents at similar latitudes.

  2. An assessment of tidal energy potential. The Lima estuary

    Energy Technology Data Exchange (ETDEWEB)

    Trigo-Teixeira, A. [Department of Civil Engineering and Architecture, Instituto Superior Tecnico, Lisbon Technical University, Av. Rovisco Pais, 1049-001 Lisboa (Portugal); Rebordao, I. [WW Consulting Engineers, Laveiras, Caxias 2760-032 (Portugal)

    2009-07-01

    A hydrodynamic model was set up for the Lima estuary (Portugal) and a preliminary assessment of the strength of tidal currents to produce tidal energy was made. To calibrate the model results were compared with measured data, and the model tuned to reproduce water levels and currents in several locations within the estuary. The data was acquired with ADCPs, during a field campaign that was planed to cover a spring-neap tide cycle, in October 2006. The Advanced Circulation Model - ADCIRC was forced with the most important harmonic constituents present in the ocean tide signal. Upstream, in the river boundary, the discharge was taken from hydrographs. The wetting and drying tool was also applied and a detailed bathymetry was considered, since there are areas in the domain where salt marshes occur, drying out at low tide. The tidal currents potential were assessed for a scenario of tidal forcing only, without any river discharge. The lower estuary is occupied by the port infrastructure and navigation channels which conflicts with any kind of equipment installation. Values of the currents and water depths given by the model indicate that some places in the main channel of the middle estuary, might be interesting to install micro turbines in the future, depending on the evolution of the requirements of this technology.

  3. The influence of abiotic factors present in the Rio de la Plata over the chromium genotoxicity

    International Nuclear Information System (INIS)

    Lopez, L.C.; Moretton, J.

    1997-01-01

    The alterations suffered by the well-known environmental genotoxic agent, Cr(V I), were studied. Cr(V I) salts were dissolved in water effluent river receptors waters such as from the Rio de la Plata. The influence of abiotic factors present in this kind of water was evaluated using the Rec. assay in Bacillus subtilis. The results detected a soluble fraction that potentiated Cr(V I) genotoxicity. This substance (or group of substances) is sensible to sterilization by heat and UV radiation, and its activity seems to decrease with particulate matter. Its genotoxicity was not affected by high concentrations of particulate matter in the Rio de la Plata water. In samples where chromium salts were added to raw river water, abiotic interference due to sterilization process occurred. A decrease in genotoxicity was found after filtration through inorganic filters (0.22 μ m) and an increase was noticed after exposure to UV radiation. (Author)

  4. Resiliencia y engagement en el sector hotelero en la ciudad de Mar del Plata

    OpenAIRE

    Redondo, Ana Isabel; Arraigada, Mariana Cecilia

    2015-01-01

    Desde el marco de la psicología de la salud ocupacional positiva, nos proponemos realizar un estudio descriptivo sobre las variables resiliencia y engagement en el sector hotelero de la ciudad de Mar del Plata. Para tal fin, se utilizaran dos instrumentos con formato de cuestionario auto-administrado, a saber: RSA (Escala de Resiliencia en Adultos) y UWES (Utrech Work Engagement Scale) que miden dichas variables a aplicar en una muestra compuesta por 80 personas, todas ellas empleados de dos ...

  5. Una herramienta cartográfica digital basada en XML para la ciudad de La Plata

    Directory of Open Access Journals (Sweden)

    Nadia Kreimer

    2010-06-01

    Full Text Available El trabajo presenta una aplicación específica desarrollada a partir la integración de dos herramientas informáticas: Google Maps y un lenguaje de programación de alto nivel, en nuestro caso Octave. La API de Google Maps en Javascript permite la construcción de objetos espaciales. Integrando el mismo con algoritmos originales que resuelvan la geocodificación de las calles de La Plata y el manejo de una base de datos es posible brindar un servicio de localización. El ejemplo que se presenta es el de la localización de las farmacias más cercanas a un cierto domicilio. Se le pide a los usuarios que ingresen su dirección; con estos datos le son devueltas las tres farmacias de turno más cercanas. El código resulta fácilmente adaptable a otro tipo de requerimientos: estaciones de servicio, restaurantes, etcétera siendo su única limitación que la geocodificación está desarrollada para la ciudad de La Plata.This paper presents a specific application developed by the integration of two tools: Google Maps and a high level programming language: Octave. The Google Maps API in Javascript allows the construction of space objects. This language integrated with algorithms that solve the original geocoding of the streets of La Plata and management of a database can provide a service location. The example presented is the location of the nearest pharmacies to a certain address. Users are prompted to enter their address and the system returns the three closest pharmacies.The code is easily adaptable to other types of requirements: gas stations, restaurants, etc.; its only limitation is that the geocoding is developed for the city of La Plata.

  6. Major hydrogeochemical processes in an Acid Mine Drainage affected estuary

    International Nuclear Information System (INIS)

    Asta, Maria P.; Calleja, Maria Ll.; Pérez-López, Rafael; Auqué, Luis F.

    2015-01-01

    Highlights: • Mixing of acid riverine water with alkaline seawater was studied in an estuary. • Combination of data and geochemical tools allowed modeling the water mixing. • The main geochemical processes were identified and for the first time quantified. • Water chemistry is the result of mixing, dissolution-precipitation and sorption. • Main reactions: gypsum and calcite dissolution and Al and Fe solids precipitation. - Abstract: This study provides geochemical data with the aim of identifying and quantifying the main processes occurring in an Acid Mine Drainage (AMD) affected estuary. With that purpose, water samples of the Huelva estuary were collected during a tidal half-cycle and ion–ion plots and geochemical modeling were performed to obtain a general conceptual model. Modeling results indicated that the main processes responsible for the hydrochemical evolution of the waters are: (i) the mixing of acid fluvial water with alkaline ocean water; (ii) precipitation of Fe oxyhydroxysulfates (schwertmannite) and hydroxides (ferrihydrite); (iii) precipitation of Al hydroxysulfates (jurbanite) and hydroxides (amorphous Al(OH) 3 ); (iv) dissolution of calcite; and (v) dissolution of gypsum. All these processes, thermodynamically feasible in the light of their calculated saturation states, were quantified by mass-balance calculations and validated by reaction-path calculations. In addition, sorption processes were deduced by the non-conservative behavior of some elements (e.g., Cu and Zn)

  7. In-stream PIT detection, estuary wetlands - Columbia River Estuary Tidal Habitats

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The goal of the tidal-fluvial estuary study is to determine the estuary's contribution to the spatial structure and life history diversity of Columbia River salmon...

  8. Salmon habitat use, tidal-fluvial estuary - Columbia River Estuary Tidal Habitats

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The goal of the tidal-fluvial estuary study is to determine the estuary's contribution to the spatial structure and life history diversity of Columbia River salmon...

  9. Gross Nitrogen Mineralization in Surface Sediments of the Yangtze Estuary

    Science.gov (United States)

    Liu, Min; Li, Xiaofei; Yin, Guoyu; Zheng, Yanling; Deng, Fengyu

    2016-01-01

    Nitrogen mineralization is a key biogeochemical process transforming organic nitrogen to inorganic nitrogen in estuarine and coastal sediments. Although sedimentary nitrogen mineralization is an important internal driver for aquatic eutrophication, few studies have investigated sedimentary nitrogen mineralization in these environments. Sediment-slurry incubation experiments combined with 15N isotope dilution technique were conducted to quantify the potential rates of nitrogen mineralization in surface sediments of the Yangtze Estuary. The gross nitrogen mineralization (GNM) rates ranged from 0.02 to 5.13 mg N kg-1 d-1 in surface sediments of the study area. The GNM rates were generally higher in summer than in winter, and the relative high rates were detected mainly at sites near the north branch and frontal edge of this estuary. The spatial and temporal distributions of GNM rates were observed to depend largely on temperature, salinity, sedimentary organic carbon and nitrogen contents, and extracellular enzyme (urease and L-glutaminase) activities. The total mineralized nitrogen in the sediments of the Yangtze Estuary was estimated to be about 6.17 × 105 t N yr-1, and approximately 37% of it was retained in the estuary. Assuming the retained mineralized nitrogen is totally released from the sediments into the water column, which contributed 12–15% of total dissolved inorganic nitrogen (DIN) sources in this study area. This result indicated that the mineralization process is a significant internal nitrogen source for the overlying water of the Yangtze Estuary, and thus may contribute to the estuarine and coastal eutrophication. PMID:26991904

  10. Spatial distribution and risk assessment of heavy metals in sediments of Shuangtaizi estuary, China

    International Nuclear Information System (INIS)

    Li, Chen; Song, Chengwen; Yin, Yanyan; Sun, Menghan; Tao, Ping; Shao, Mihua

    2015-01-01

    Highlights: • Five heavy metals are analyzed in the sediments from Shuangtaizi estuary. • Particle size of the sediment effects the concentration of heavy metals. • Pb, Cu, Zn and Hg pose low ecological risks in the Shuangtaizi estuary. • Heavy metal pollution in Shuangtaizi estuary is mainly dominated by Cd. - Abstract: In order to evaluate the spatial distribution and potential ecological risk of Pb, Cu, Zn, Cd, and Hg, the surface sediments were collected from 18 sites in the Shuangtaizi estuary. The concentrations of Pb, Cu, Zn, Cd, and Hg were analyzed by atomic absorption spectrophotometry and atomic fluorescence spectrometry after digestion. The particle sizes of the sediments were analyzed using a laser diffraction particle size analyzer. The results show that the heavy metal contents in the sediments are observed in the following order: Zn (18.25–126.75 mg/kg) > Pb (4.38–9.65 mg/kg) > Cu (1.80–17.68 mg/kg) > Cd (0.241–0.764 mg/kg) > Hg (0.007–0.021 mg/kg). In comparison with the concentrations of heavy metals in other regions, the concentrations of Pb, Cu, and Zn in the Shuangtaizi estuary are generally low, and the Cd concentrations are close to those reported in other regions. Both the potential ecological risk index and the geoaccumulation index reveal that the heavy metal pollution in Shuangtaizi estuary is mainly dominated by Cd

  11. The International Summer School on Land Cover Change and Hydroclimate of the La Plata Basin

    Science.gov (United States)

    Berbery, Ernesto Hugo; Herdies, Dirceu L.; Alcaraz-Segura, Domingo; de Goncalves, Luis G. G.; Lettenmaier, Dennis P.; Toll, David

    2011-01-01

    The La Plata Basin (LPB) in southern South America has been subject to land cover and land use changes (LCLUCs) since colonial times and with an accelerated rate in the last decades and over extensive areas. The work of Ameghino even suggested that there were relations between those land use changes and the frequency of droughts and floods in the region. Despite this early knowledge, not much is known of the potential impacts of LCLUC on the hydroclimate of the La Plata basin. Besides, over the last century much of the La Plata Basin has had a reported increase in precipitation and heavy rains, and these changes along with an increase in population growth - have resulted in more adverse effects from flooding. To draw attention to these issues, during two weeks in November 2009 the International Summer School on Land Cover Change and Hydroclimate of the La Plata Basin was organized at the grounds of the Itaip Hydropower Plant in Brazil. The school was the result of the combination of interests between the La Plata Basin Regional Hydroclimate Project, the Inter-American Institute for Global Change Research (IAI), and the International Hydroinformatics Center (IHC) in Itaip . LPB is an umbrella project endorsed by the Global Energy and Water Cycle Experiment (GEWEX) and the Climate Prediction and Variability (CLIVAR), both of the World Climate Research Programme (WCRP). LPB has made a priority to train young scientists and promote interdisciplinary collaborations in areas related to Climate, Hydrology, Ecology and Agriculture. The IAI, with a similar agenda, was a natural partner to develop this Summer School, which in turn benefited from Itaipu s interest in relating with the scientific community of neighboring countries. The choice of location (Itaip Technological Park) was made so that participants could relate research usually done at academic institutions to applications and operations at one of the largest hydropower plants in the world. The school was attended

  12. El premio de la plata y la devaluación del vellón en Guipúzcoa en el siglo XVII

    Directory of Open Access Journals (Sweden)

    Álvaro Aragón Ruano

    2001-01-01

    Full Text Available El presente artículo analiza la evolución del premio de la plata durante el siglo xvii en Guipúzcoa, donde aparecen dos modelos de comportamiento, siempre en relación con la abundancia y movimiento de la plata, que es el principal factor que explica las variaciones del premio. Se constata, no obstante, que en cada localidad los premios son diferentes, lo que demuestra la autonomía de las economías locales de Antiguo Régimen. Así mismo, hay que decir que las mayores repercusiones de este fenómeno se dejaron sentir en los mercados y en las transacciones locales, afectando principalmente a los consumidores. De todas formas, se demuestra la necesidad de seguir realizando investigaciones en los diferentes territorios que formaban la Corona, y desterrar definitivamente la generalización de datos como los de Hamilton.The next article analises the evolution of the silver's prize during the XVIIth Century in Guipúzcoa, where there arise two trends of behaviour, always related to the movement and abundance of the silver, which are the main factors that explain the changes of the prize. It is verified, nevertheless, that in each town the prizes are different, which shows the local economies' autonomy in the Ancient Regime. Besides, we should add that the main repercussion of this phenomenon was reflected in the local markets and transactions, mainly affecting the communities. In any case, it is stated the need to continué investigating in the different territories which formed the Crown, and to stamp out definetely the generalization of data, such as Hamilton's one.

  13. Seasonal, lunar and tidal control of ichthyoplankton dynamics at the interface between a temperate estuary and adjacent coastal waters (western Portugal

    Directory of Open Access Journals (Sweden)

    Ana Lígia Primo

    2011-11-01

    Full Text Available Influence of season, lunar-tide cycle and tide on ichthyoplankton at the interface between Mondego estuary and the adjacent coast and on up-estuary transport was evaluated. Seasonal samples were collected at a fixed station at the mouth of the estuary during diel cycles, at neap and spring tides. Additionally, four sampling stations along the estuary were assessed. Pomatoschistus spp. was the main estuarine taxon, while Sardina pilchardus and Parablennius pilicornis were the most important marine species. Ichthyoplankton entrance and transport along the estuary presented a seasonal pattern with higher densities during summer. Lunar-tide cycle also represented an important influence, structuring communities that reach the estuary and their subsequent distribution. Solea senegalensis and Sardina pilchardus seemed to take advantage of spring tides to enter the estuary. S. pilchardus appear to be using tides to move upstream of the estuary. Ichthyoplankton entrance in the estuary seemed related to species spawning period, while its distribution within the estuary depends on in situ spawning and on the capacity of species to counteract currents and river flow. The present study provides a better understanding of ichthyoplankton dynamics at the interface of two coastal systems, reinforcing knowledge of the lunar-tide cycle influence on ichthyoplankton communities.

  14. Assessment of the conservation priority status of South African estuaries for use in management and water allocation

    CSIR Research Space (South Africa)

    Turpie, JK

    2002-04-01

    Full Text Available The future health and productivity of South Africa's approximately 250 estuaries is dependent on two main factors; management and freshwater inputs. Both management and water allocation decisions involve trade-offs between conservation and various...

  15. Soil response to long-term projections of extreme temperature and precipitation in the southern La Plata Basin

    Science.gov (United States)

    Pántano, Vanesa C.; Penalba, Olga C.

    2017-12-01

    Projected changes were estimated considering the main variables which take part in soil-atmosphere interaction. The analysis was focused on the potential impact of these changes on soil hydric condition under extreme precipitation and evapotranspiration, using the combination of Global Climate Models (GCMs) and observational data. The region of study is the southern La Plata Basin that covers part of Argentine territory, where rainfed agriculture production is one of the most important economic activities. Monthly precipitation and maximum and minimum temperatures were used from high quality-controlled observed data from 46 meteorological stations and the ensemble of seven CMIP5 GCMs in two periods: 1970-2005 and 2065-2100. Projected changes in monthly effective temperature and precipitation were analysed. These changes were combined with observed series for each probabilistic interval. The result was used as input variables for the water balance model in order to obtain consequent soil hydric condition (deficit or excess). Effective temperature and precipitation are expected to increase according to the projections of GCMs, with few exceptions. The analysis revealed increase (decrease) in the prevalence of evapotranspiration over precipitation, during spring (winter). Projections for autumn months show precipitation higher than potential evapotranspiration more frequently. Under dry extremes, the analysis revealed higher projected deficit conditions, impacting on crop development. On the other hand, under wet extremes, excess would reach higher values only in particular months. During December, projected increase in temperatures reduces the impact of extreme high precipitation but favours deficit conditions, affecting flower-fructification stage of summer crops.

  16. Phosphorus fractionation distribution in Guapimirim estuary: SE Brazil.

    Science.gov (United States)

    Vicente, Michel Arthur Faria; de Melo, Gustavo Vaz; Baptista Neto, José Antonio; de Oliveira, Allan Sandes

    2016-01-01

    The Guapimirim estuary is the main tributary of Guanabara bay and is located in the northeast portion. Although it is protected, this estuary has been experiencing strong anthropogenic pressure, which has led to changes in the natural characteristics. Large amounts of sewage are dumped into the bay through tributaries, thereby changing the water and bottom sediment quality. One of the main elements of sewage is phosphorus. Despite its importance to life, a high concentration of this nutrient in the environment can result in eutrophication. This work describes the phosphorus distribution in its different fractions in the bottom sediment at 16 stations located in the main channel of the Guapimirim estuary. These results are correlated with data on grain size, organic matter and calcium carbonate content in the bottom sediment and with physicochemical parameters of the bottom water. The grain size decreases toward the mouth of the estuary, whereas the organic matter and carbonate content increase. The salinity increases significantly at 3.5 km upstream from the mouth, where there is also a notable increase in fine sediments; the same site is the mean position of the salinity front. The temperature and pH increase in the same direction. The Pinorg-total ranges between 3.18 and 7.13 µmol g(-1), increasing toward the mouth. The same trend is observed for the other phosphorus fractions P-Ca, P-Fe and P-f.a., which range from 0.68 to 1.91, 0.79 to 1.71 and 0.03 to 0.93 µmol g(-1), respectively. The P-Ca and P-Fe fractions are the most representative in the Pinorg-total, occurring at 26.3 and 26.0 %, respectively.

  17. Main Memory

    NARCIS (Netherlands)

    P.A. Boncz (Peter); L. Liu (Lei); M. Tamer Özsu

    2008-01-01

    htmlabstractPrimary storage, presently known as main memory, is the largest memory directly accessible to the CPU in the prevalent Von Neumann model and stores both data and instructions (program code). The CPU continuously reads instructions stored there and executes them. It is also called Random

  18. Carbon dioxide emissions from Indian monsoonal estuaries

    Science.gov (United States)

    Sarma Vedula, VSS

    2012-07-01

    The oceans act as a net sink for atmospheric CO2, however, the role of coastal bodies on global CO2 fluxes remains unclear due to lack of data. The estimated absorption of CO2 from the continental shelves, with limited data, is 0.22 to 1.0 PgC/y, and of CO2 emission by estuaries to the atmosphere is 0.27 PgC/y. The estimates from the estuaries suffer from large uncertainties due to large variability and lack of systematic data collection. It is especially true for Southeast Asian estuaries as the biogeochemical cycling of material are different due to high atmospheric temperature, seasonality driven by monsoons, seasonal discharge etc. In order to quantify CO2 emissions from the Indian estuaries, samples were collected at 27 estuaries all along the Indian coast during discharge wet and dry periods. The emissions of CO2 to the atmosphere from Indian estuaries were 4-5 times higher during wet than dry period. The pCO2 ranged between ~300 and 18492 microatm which were within the range of world estuaries. The mean pCO2 and particulate organic carbon (POC) showed positive relation with rate of discharge suggesting availability of high quantities of organic matter that led to enhanced microbial decomposition. The annual CO2 fluxes from the Indian estuaries, together with dry period data available in the literature, amounts to 1.92 TgC which is >10 times less than that from the European estuaries. The low CO2 fluxes from the Indian estuaries are attributed to low flushing rates and less human settlements along the banks of the Indian estuaries.

  19. Morphology and modern sedimentary deposits of the macrotidal Marapanim Estuary (Amazon, Brazil)

    Science.gov (United States)

    Araújo da Silva, Cléa; Souza-Filho, Pedro Walfir M.; Rodrigues, Suzan W. P.

    2009-03-01

    The northern Brazilian coast, east of the Amazon River is characterized by several macrotidal estuarine systems that harbor large mangrove areas with approximately 7600 km 2. The Marapanim Estuary is influenced by macrotidal regime with moderate waves influence. Morphologic units were investigated by using remote sensing images (i.e., Landsat-7 ETM+, RADARSAT- 1 Wide and SRTM) integrated with bathymetric data. The modern sedimentary deposits were analyzed from 67 cores collected by Vibracore and Rammkersonde systems. Analysis of morphology and surface sedimentary deposits of the Marapanim River reveal they are strongly influenced by the interaction of tidal, wave and fluvial currents. Based on these processes it was possible to recognize three distinct longitudinal facies zonation that revels the geological filling of a macrotidal estuary. The estuary mouth contain fine to medium marine sands strongly influenced by waves and tides, responsible for macrotidal sandy beaches and estuarine channel development, which are characterized by wave-ripple bedding and longitudinal cross-bedding sands. The estuary funnel is mainly influenced by tides that form wide tidal mudflats, colonized by mangroves, along the estuarine margin, with parallel laminations, lenticular bedding, root fragments and organic matter lenses. The upstream estuary contains coarse sand to gravel of fluvial origin. Massive mud with organic matter lenses, marks and roots fragments occur in the floodplain accumulates during seasonal flooding providing a slowly aggrading in the alluvial plain. This morphologic and depositional pattern show easily a tripartite zonation of a macrotidal estuary, that are in the final stage of filling.

  20. Worldwide patterns of fish biodiversity in estuaries: Effect of global vs. local factors

    Science.gov (United States)

    Pasquaud, Stéphanie; Vasconcelos, Rita P.; França, Susana; Henriques, Sofia; Costa, Maria José; Cabral, Henrique

    2015-03-01

    The main ecological patterns and the functioning of estuarine ecosystems are difficult to evaluate due to natural and human induced complexity and variability. Broad geographical approaches appear particularly useful. This study tested, at a worldwide scale, the influence of global and local variables in fish species richness in estuaries, aiming to determine the latitudinal pattern of species richness, and patterns which could be driven by local features such as estuary area, estuary mouth width, river flow and intertidal area. Seventy one estuarine systems were considered with data obtained from the literature and geographical information system. Correlation tests and generalized linear models (GLM) were used in data analyses. Species richness varied from 23 to 153 fish species. GLM results showed that estuary area was the most important factor explaining species richness, followed by latitude and mouth width. Species richness increased towards the equator, and higher values were found in larger estuaries and with a wide mouth. All these trends showed a high variability. A larger estuary area probably reflects a higher diversity of habitats and/or productivity, which are key features for estuarine ecosystem functioning and biota. The mouth width effect is particularly notorious for marine and diadromous fish species, enhancing connectivity between marine and freshwater realms. The effects of river flow and intertidal area on the fish species richness appear to be less evident. These two factors may have a marked influence in the trophic structure of fish assemblages.

  1. Pollution in the estuary of the Baracoa river, La Habana, Cuba

    Directory of Open Access Journals (Sweden)

    Regla Duthit Somoza

    2011-04-01

    Full Text Available The environmental quality of the Baracoa river estuary was studied from the physic (temperature and salinity, chemic variables (dissolved oxygen, oxygen biochemical demand (DBO, oxygen chemical demand (DQO, nitrogen cycle, inorganic phosphorus and total phosphorus and the microbiological variables (total and thermotolerant coliforms and faecal streptococci. The samplings were made on February 2006, May and October 2007. Spatial distribution of the physical and chemical parameters measured suggests that the estuary is dominated by the marine conditions. The salinity and temperature analyses show that in general the characteristics of the estuary could be influenced by the contribution of the river basin drainage. In general, the concentrations of the measured parameters in the Baracoa river estuary, strongly suggest that this area is under influence of human activities on the river basin, due to the low levels of dissolved oxygen and an oxygen average deficit of -1.6 mg/L. nthropogenic actions in this estuary are mainly related to the emission of domestic and farming rejects without suitable treatment. This is visibly associated with the observed values of the total coliforms concentrations as well as the concentration of faecal streptococci, that surpassed reference values from the Cuban norm for water quality, following on bad or doubtful quality levels pointing out negatively measurements made next to the communication channel the estuary and the El Doctor lagoon.

  2. Main Memory

    OpenAIRE

    Boncz, Peter; Liu, Lei; Özsu, M.

    2008-01-01

    htmlabstractPrimary storage, presently known as main memory, is the largest memory directly accessible to the CPU in the prevalent Von Neumann model and stores both data and instructions (program code). The CPU continuously reads instructions stored there and executes them. It is also called Random Access Memory (RAM), to indicate that load/store instructions can access data at any location at the same cost, is usually implemented using DRAM chips, which are connected to the CPU and other per...

  3. Multibiomarker assessment of three Brazilian estuaries using oysters as bioindicators

    International Nuclear Information System (INIS)

    Valdez Domingos, F.X.; Azevedo, M.; Silva, M.D.; Randi, M.A.F.; Freire, C.A.; Silva de Assis, H.C.; Oliveira Ribeiro, C.A.

    2007-01-01

    Oysters have been largely employed as bioindicators of environmental quality in biomonitoring studies. Crassostrea rhizophorae was selected to evaluate the health status of three estuarine areas impacted by anthropogenic activities along the Brazilian coast, in three estuarine complexes, ranging in latitude from 7 to 25 deg. S. In each estuary three sites were sampled in Winter and in Summer: a site considered as reference, and two sites next to contamination sources. Condition index was similar at all sites and estuaries, with the highest values found for Itamaraca oysters in Summer. Necrosis, hyperplasia, mucocyte hypertrophy and fusion of ordinary filaments were the main histopathological lesions observed. Muscle cholinesterase activity was overall similar, but with a strong seasonal effect. Inhibition or activation of branchial total ATPase and Na,K-ATPase activities at the contaminated sites was observed. The health status of these estuarine areas is quite similar, and the combined use of biomarkers is recommended

  4. A Marriage Of Larval Modeling And Empirical Data: Linking Adult, Larval And Juvenile Scallops In An Estuary

    Science.gov (United States)

    Bayer, S.; Wahle, R.; Brooks, D. A.; Brady, D. C.

    2016-02-01

    The giant sea scallop, Placopecten magellanicus, is a commercially valuable sedentary broadcast spawner that occupies offshore banks and coastal bays and estuaries in the Northwest Atlantic. Although area closures have helped repopulate depleted scallop populations, little is known about whether populations at densities that yield larvae supply local or distant populations. Surveying scallop populations in the Damariscotta River estuary in Maine during the 2013 and 2014 spawning seasons, and settling out spat bags to collect settling larvae along the gradient of the estuary, we were able to compare adult densities to newly settled juvenile (`spat') abundance. Using the location where we found a high density of adults, we incorporated previously published behavior, pelagic larval duration, wind and current data into a particle dispersal model within the estuary to determine likely sinks for larvae from the 2013 and 2014 spawning seasons. Preliminary model simulations demonstrate where in the estuary swimming is effective in affecting water column position for larvae, and that most larvae are retained much closer to the mouth of the estuary than previously expected. Combining larval dispersal modeling with empirical data on adult densities and spat settlement on the scale of an embayment or estuary may be helpful in determining sources, sinks and areas that are both sources and sinks for shellfish species that are endangered or economically critical. This may aid in determining small area closures or Marine Protected Areas along coastal regions in the Gulf of Maine and beyond.

  5. Trapping of sediment in tidal estuaries

    NARCIS (Netherlands)

    Chernetsky, A.

    2012-01-01

    An estuary is an ideal habitat for various aquatic species. At the same time, estuaries and adjacent rivers are used as fast navigation routes between the coastal and inland territories. The fast industrial development and the subsequent growth of cities and trade have led to large-scale

  6. Microplastic in three urban estuaries, China

    International Nuclear Information System (INIS)

    Zhao, Shiye; Zhu, Lixin; Li, Daoji

    2015-01-01

    Estuarine Microplastics (MPs) are limited to know globally. By filtering subsurface water through 330 μm nets, MPs in Jiaojiang, Oujiang Estuaries were quantified, as well as that in Minjiang Estuary responding to Typhoon Soulik. Polymer matrix was analyzed by Raman spectroscopy. MP (<5 mm) comprised more than 90% of total number plastics. The highest MPs density was found in Minjiang, following Jiaojiang and Oujiang. Fibers and granules were the primary shapes, with no pellets found. Colored MPs were the majority. The concentrations of suspended microplastics determine their bioavailability to low trophic organisms, and then possibly promoting the transfer of microplastic to higher trophic levels. Polypropylene and polyethylene were the prevalent types of MPs analyzed. Economic structures in urban estuaries influenced on MPs contamination levels. Typhoon didn't influence the suspended MP densities significantly. Our results provide basic information for better understanding suspended microplastics within urban estuaries and for managerial actions. - Highlights: • Suspended microplastic were investigated within three densely populated/developed urban estuaries, China. • Economical structures may contribute to the abundances of microplastic particles within the studied estuaries. • Typhoon Soulik didn't influence microplastic densities in the water column of Minjiang Estuary. • Microplastics (<5 mm in diameter) dominated more than 90% of the total plastic by number. - Suspended microplastics (MPs) levels were quantified within three urban estuaries, China. MPs densities were consistent with the urban economical structure, and that in Minjiang were unaffected by Typhoon.

  7. The Mntafufu and Mzamba River estuaries

    African Journals Online (AJOL)

    1989-03-14

    Mar 14, 1989 ... A survey of the fish fauna of Transkei estuaries. Part Four: The Mntafufu and Mzamba River estuaries. E.E. Plumstead • and J.F. Prinsloo. Department of Zoology, University of Transkei, Private Bag X1, Unitra, Umtata, Republic of Transkei. H.J. Schoonbee. Department of Zoology, Rand Afrikaans University, ...

  8. Generación controlada de nanocoloides de plata en materiales silíceos amorfos

    Directory of Open Access Journals (Sweden)

    Gil, C.

    2004-04-01

    Full Text Available Amorphous silica-based materials bulk and superficially doped with silver nanocolloids were prepared. Bulk doped glasses were obtained by conventional melting and doped monolithic slabs by sol-gel. Superficially doped glasses were obtained by ion-exchange and doped coatings by sol-gel. The samples were characterised by TEM and UV-VIS spectrophotometry. Depending on the composition, the silver incorporation process, and the thermal treatments, several colourings were obtained. By controlling these parameters, metallic silver nanocolloids can be generated in the matrices studied. Colloids aggregation and growing up depends on the matrix nature and on the experimental process carried out.

    Se prepararon materiales silíceos amorfos dopados con nanocoloides de plata en masa y en superficie. Se obtuvieron vidrios dopados en masa por fusión convencional y láminas monolíticas dopadas por sol-gel. Asimismo se prepararon vidrios dopados superficialmente por cambio iónico y recubrimientos dopados por sol-gel. Los materiales se caracterizaron por MET y espectrofotometría UV-VIS. Dependiendo de la composición del material, del proceso de incorporación de la plata y de los tratamientos térmicos, se obtuvieron diferentes coloraciones. El control de estas variables permitió generar nanocoloides metálicos de plata en las matrices estudiadas. La agregación y crecimiento de los coloides depende de la naturaleza de la matriz y del proceso experimental utilizado.

  9. [Speciation and Risk Characteristics of Heavy Metals in the Sediments of the Yangtze Estuary].

    Science.gov (United States)

    Yin, Su; Feng, Cheng-hong; Li, Yang-yang; Yin, Li-feng; Shen, Zhen-yao

    2016-03-15

    Based on the investigation on the distribution of total contents and speciation of 8 heavy metals (As, Cd, Cr, Cu, Hg, Ni, Pb, Zn) in the surface sediments at 14 typical sites of the Yangtze Estuary during three hydrological seasons ( wet, normal, and dry seasons) , this study applied equilibrium partitioning approach to build the sediment quality guidelines (SQGs) of the Yangtze Estuary, and assessed ecological risks of the heavy metals. The relationship between ecological risk and speciation of heavy metals was also revealed. The results showed that, except for Cd, the residual fraction was the main speciation of heavy metals, especially for As, Cr and Hg, their residual fraction proportions were all over 90%. The sediment quality guidelines of the Yangtze Estuary for As, Cd, Cr, Cu, Hg, Ni, Pb, Zn were 43.29, 0.672, 79.65, 19.08, 0.569, 339.09, 30.87, 411.36 µg · g⁻¹, respectively. Cu had the highest ecological risk to aquatic organisms. The upstream of Yangtze Estuary was mainly affected by Yangtze River runoff, where the risks were relatively high in wet season and relatively low in normal and dry seasons. However, the downstream of the estuary was mainly affected by municipal sewage of cities like Shanghai, where the risks were relatively high, especially in normal and dry seasons. There were three different relationships between the ecological risks and speciation of the eight heavy metals.

  10. Preferencias de los huéspedes de hostels de la ciudad de La Plata

    OpenAIRE

    De la Cruz, Gastón Miguel

    2013-01-01

    La presente tesis tiene como objeto estudiar las preferencias de huéspedes de un grupo de hostels de la ciudad de La Plata, con el fin de determinar la existencia de una demanda que tenga como principal preferencia a un atributo de índole social. Para cumplir con este objetivo se utilizó la técnica estadística análisis conjunto (conjoint analysis en inglés) la cual obligó a descomponer el concepto hostel en seis (6) atributos, de los cuales tres (3) atributos entran en la definición de índole...

  11. Conflicto de identidad : indefinición sexual en tres poetas de la Edad de Plata

    OpenAIRE

    Gómez Garrido, Marta

    2013-01-01

    Artículo sobre la presencia de un conflicto identitario relacionado con el género en la obra de tres poetas de la llamada Edad de Plata Española: Lucía Sánchez Saornil, Ana María Martínez Sagi y Carmen Conde. Article about the existence of a gender-related identity conflict in three female poets of the Silver Age of Spanish Literature: Lucía Sánchez Saornil, Ana María Martínez Sagi and Carmen Conde.

  12. Satisfacción del cliente de obras particulares de la Municipalidad de La Plata

    OpenAIRE

    Pizzorno, Mariano

    2013-01-01

    Evaluación del nivel de satisfacción de los clientes del servicio de Obras Particulares de la Municipalidad de La Plata en relación a: - El grado de conocimiento de los servicios que brinda el municipio. - La imagen que tiene el ciudadano del municipio. - La importancia de cada atributo del servicio: en relación a la atención al público, a la infraestructura y equipamiento y a los procesos para la realización de trámites. - El grado de satisfacción del ...

  13. Tostación de un concentrado refractario de oro y plata

    Directory of Open Access Journals (Sweden)

    Coronado, J. H.

    2012-06-01

    Full Text Available In processing of precious metal ores with high pyrite content, refractory concentrates are obtained, which are difficult to process. A refractory gold and silver concentrate was leached with sodium cyanide. Results show low extraction percentages, being 34 % of gold and 40 % of silver. A roasting method to oxidize the concentrate was used, making it more susceptible to cyanidation, hence a more efficient way to extract precious metals. The variables include roasting temperature and roasting and cyanidation time. In addition, the hot calcine was added to the leaching solution at room temperature to analyze the effect on particle size and recovery. The best results, although not entirely satisfactory (50 % of gold and 61 % of silver were obtained by roasting the concentrate for 4 h at 600 °C, followed by cyanidation for 20 h. The lime consumption to raise the pH to about 11.3 was increased markedly to 25 kg/m3.

    En el procesamiento de minerales de metales preciosos con altos contenidos de pirita, se obtienen concentrados refractarios difíciles de procesar. En este estudio se lixivió un concentrado refractario de oro y plata con cianuro de sodio, obteniéndose extracciones de 34 % para oro y 40 % para plata. Se utilizó el método de tostación para oxidar el concentrado, haciéndolo más susceptible a la cianuración, y extraer más eficientemente el oro y la plata. Las variables analizadas fueron: temperatura de tostación y tiempos de tostación y cianuración. Además, la calcina caliente se agregó a la solución lixiviante a temperatura ambiente para analizar el efecto en el tamaño de partícula y recuperación. Los mejores resultados, aunque no del todo satisfactorios (50 % oro y 61 % plata, se obtuvieron mediante tostación del concentrado durante 4 h a temperaturas de 600 °C, seguido de una cianuración de 20 h. El consumo de cal para elevar el pH a 11,3, se incrementó notablemente hasta 25 kg/m3.

  14. Archivo de placas astrométricas del Observatorio de La Plata

    Science.gov (United States)

    di Sisto, R.; Orellana, R. B.

    Se ha realizado una base de datos con las placas fotográficas obtenidas con el Astrográfico del Observatorio de La Plata. Se han clasificado un total de 3000 placas obtenidas para asteroides y cometas. El acceso a la base de datos se hará por FTP y la misma contendrá la siguiente información: fecha y tiempo de exposición, coordenadas del centro de placa, tipo de emulsión fotográfica, estado de la placa, objeto fotografiado.

  15. DISPERSIÓN DE LUZ POR UNA NANOPARTÍCULA DE PLATA CON FORMA ESFEROIDAL PROLATA

    OpenAIRE

    Alejandro Castellanos Jaramillo; Arnulfo Castellanos Moreno

    2016-01-01

    Usando el método de diferencias finitas en el dominio del tiempo se estudia la incidencia y dispersión de radiación electromagnética de una nanopartícula de plata con forma esferoidal prolata. Se obtiene la distribución de frecuencias del vector de Poynting dispersado en el régimen casi estacionario y se estudia el estado de radiación de la nanopartícula cuando el pulso de luz ha dejado de perturbarla. Los resultados son de interés didáctico

  16. Gravimetric study on the western edge of the Rio de La Plata craton

    International Nuclear Information System (INIS)

    Rame, G; Miro, R

    2010-01-01

    This work is about the gravimetric study on the western edge of the Rio de la Plata craton which belongs to the Gondwana fragment in the south of Brazil, Uruguay and central eastern of Argentina. The work consisted of a survey of 332 gravimetric and topographic stations extended from the western edge of the Sierra Chica de Cordoba up to 200 km east on the pampas. The gravity values observed (gobs) were obtained using a LaCoste §Rom berg gravimeter G-961 and 200T Sodin both with 0.01 mGal, referred to IGSN71 (International Gravity Standardization Net 1971) network

  17. DISPERSIÓN DE LUZ POR UNA NANOPARTÍCULA DE PLATA CON FORMA ESFEROIDAL PROLATA

    Directory of Open Access Journals (Sweden)

    Alejandro Castellanos Jaramillo

    2016-06-01

    Full Text Available Usando el método de diferencias finitas en el dominio del tiempo se estudia la incidencia y dispersión de radiación electromagnética de una nanopartícula de plata con forma esferoidal prolata. Se obtiene la distribución de frecuencias del vector de Poynting dispersado en el régimen casi estacionario y se estudia el estado de radiación de la nanopartícula cuando el pulso de luz ha dejado de perturbarla. Los resultados son de interés didáctico

  18. Programas de salud sexual y reproductiva y maternidad adolescente en La Plata (Buenos Aires, Argentina

    Directory of Open Access Journals (Sweden)

    Susana Ortale

    2009-12-01

    Full Text Available La mirada estigmatizante de la maternidad en la adolescencia y el interés por controlar la sexualidad por parte del sector sanitario, es reciente y diferente para hombres y mujeres. Sabemos que las categorías género y edad, en tanto construcciones culturales que aluden a relaciones básicas de desigualdad -atravesadas por estructuras económico-políticas particulares-, están cargadas de significados que se dirimen en un campo social predispuesto a reforzar estereotipos naturalizantes y relaciones de dominación. El estudio se ubica en la problemática general del reconocimiento de derechos presente en los programas de salud sexual y reproductiva que tienen como destinatarias a mujeres adolescentes pobres. El recorte pone en foco el contraste entre el marco normativo y el significado que asume la maternidad para las adolescentes. Para ello, se analizan programas de salud nacionales, de la Pcia. de Buenos Aires y de la municipalidad de La Plata y discursos obtenidos en entrevistas realizadas a veinte adolescentes residentes en barrios pobres de la ciudad de La Plata. El análisis de los programas explora la incorporación del enfoque de género y la interpretación de los problemas de sexualidad/reproducción de l@s adolescentes en el marco de los derechos humanos y el de los discursos de las entrevistadas indaga su interpelación.Stigmatizing gaze of teenage motherhood and the aim to control the sexuality from the health sector, is recent and different for men and women. We know that gender and age categories, as cultural constructions that refer to basic relations of inequality-crossed by particular political-economic structures, are loaded with meanings that are settled in a social and naturalizing field predisposed to reinforce stereotypes and relations of domination. The study is placed in the general problem of aknowledgement of rights in the programs of sexual and reproductive health in adolescent girls from low environment. This frame

  19. Distribution and sources of polycyclic aromatic hydrocarbons in surface sediments of rivers and an estuary in Shanghai, China

    International Nuclear Information System (INIS)

    Ying Liu; Ling Chen; Zhao Jianfu; Huang Qinghui; Zhu Zhiliang; Gao Hongwen

    2008-01-01

    Concentrations, spatial distribution and sources of 17 polycyclic aromatic hydrocarbons (PAHs) and methylnaphthalene were investigated in surface sediments of rivers and an estuary in Shanghai, China. Total PAH concentrations, excluding perylene, ranged from 107 to 1707 ng/g-dw. Sedimentary PAH concentrations of the Huangpu River were higher than those of the Yangtze Estuary. The concentration of the Suzhou River was close to the average concentration of the Huangpu River. PAHs source analysis suggested that, in the Yangtze Estuary, PAHs at locations far away from cities were mainly from petrogenic sources. At other locations, both petrogenic and pyrogenic inputs were significant. In the Huangpu and Suzhou Rivers, pyrogenic input outweighed other sources. The pyrogenic PAHs in the upper reaches of the Huangpu River were mainly from the incomplete combustion of grass, wood and coal, and those in the middle and lower reaches were from vehicle and vessel exhaust. - Surface sediments of two rivers and an estuary in Shanghai were contaminated by PAHs

  20. From fresh water to the slope: fish community ecology in the Río de la Plata and the sea beyond Desde el agua dulce hasta el talud: ecología de comunidades de peces en el Río de la Plata y el mar adyacente

    Directory of Open Access Journals (Sweden)

    Mirta L García

    2010-01-01

    Full Text Available The spatial pattern of fish assemblages and its relationship with factors along an environment gradient, from fresh to marine water environment along the Río de la Plata estuary (36ºS, 56ºW the shelf and part of the slope, was examined using data from 22 sampling stations. Fish were sampled from all station with an Engel type trawl (200 mm stretched mesh in the wings, 120 mm stretched mesh in the cod ends, 4 m vertical opening and 15 m horizontal aperture towed at 4 knots for 20 to 30 min per set. Cluster analysis and ordination analysis MDS were used to define spatial distribution of fish assemblages based on fish composition (abundance and biomass. BIO-ENV process was used to estimate assemblage association with depth, temperature and salinity of surface and bottom waters. The results of these analyses showed that the fish community along the riverine-marine gradient was structured in four assemblages: riverine, estuarine, shelf and slope. These assemblages were found to differ significantly in their species composition. Each assemblage was characterized by several common and discriminator species and characterized by differing environmental conditions. Bottom salinity and bottom temperature were the environmental variables most strongly associated with differences in assemblage structure across the various areas. The changes in assemblage structure between areas were gradual, with no sharp boundaries.Se analizó el patrón espacial de las asociaciones de peces y su relación con los factores ambientales a lo largo del gradiente desde el agua dulce en el Río de la Plata hasta la parte superior del talud. Los peces fueron muestreados en 22 estaciones con una red de arrastre de fondo tipo Engel (200 mm de abertura de malla en las alas, 120 en el copo, 4 m de abertura vertical y 15 m de abertura horizontal con una velocidad de arrastre de 4 nudos durante 20 a 30 min. Para definir la distribución espacial de las asociaciones de peces basadas

  1. Characteristics of Wind Generated Waves in the Delaware Estuary

    Science.gov (United States)

    Chen, J. L.; Ralston, D. K.; Geyer, W. R.; Chant, R. J.; Sommerfield, C. K.

    2016-02-01

    Coastal marshes provide important services for human uses such as fishery industry, recreation, ports and marine operations. Bombay Hook Wildlife Refuge, located along the western shore of the Delaware Estuary, has experienced substantial loss of salt marsh in recent decades. To evaluate the importance of different mechanisms which cause observed shoreline retreat, wave gauges were deployed along the dredged navigation channel and shoreline in the Delaware Estuary. A coupled wave and circulation modeling system (SWAN/ROMS) based on the most recent bathymetry (last updated 2013) is validated with waves observed during both calm and energetic conditions in November 2015. Simulation results based on different model parameterizations of whitecapping, bottom friction and the wind input source are compared. The tendency of observed wave steepness is more similar to a revised whitecapping source term [Westhuysen, 2007] than the default in SWAN model. Both model results and field data show that the generation/dissipation of waves in the Delaware estuary is determined by the local wind speed and channel depth. Whitecapping-induced energy dissipation is dominant in the channel, while dissipation due to bottom friction and depth-induced breaking become important on lateral shoals. To characterize the effects of wind fetch on waves in estuaries more generally, simulations with an idealized domain and varying wind conditions are compared and the results are expressed in terms of non-dimensional parameters. The simulations based on a 10m-depth uniform idealized channel show that the dissipation of waves is mainly controlled by whitecapping in all wind conditions. Under strong wind conditions (wind speed >10m/s) the effect of bottom friction becomes important so the simulated wave heights are no longer linearly correlated with wind speed.

  2. A Darwinian mystery: fluctuations in runoff from the la Plata basin (Alexander von Humboldt Medal Lecture)

    Science.gov (United States)

    Clarke, R. T.

    2012-04-01

    During the voyage of HMS Beagle, Charles Darwin sailed in a small boat along the River Paraná, a major tributary of the la Plata drainage system. He wrote about the occurrence of severe droughts (the latest of which had been termed the "gran seco") alternating with periods of severe flooding. From reports received, he concluded that these events appeared to be cyclic with a period "of about fifteen years". Because extended periods of low flow in Brazilian rivers are of immense economic importance, the presentation describes a search for the material which led Darwin to this conclusion. A prolonged period of low flow in another la Plata tributary - the River Paraguay - not unlike the "gran seco" reported by Darwin, has occurred more recently; if such low flows were to recur in the future, the consequences would be severe for a region where more than 70% of energy is supplied by hydropower. A priori considerations suggest the use of statistical long-memory models for predicting River Paraguay water-levels, and some preliminary results from their use are presented.

  3. Assessing residual hydropower potential of the La Plata Basin accounting for future user demands

    Directory of Open Access Journals (Sweden)

    I. Popescu

    2012-08-01

    Full Text Available La Plata Basin is shared by five countries (Argentina, Bolivia, Brazil, Paraguay and Uruguay, which have fast growing economies in South America. These countries need energy for their sustainable development; hence, hydropower can play a very important role as a renewable clean source of energy. This paper presents an analysis of the current hydropower production and electricity demand in La Plata Basin (LPB, and it analyses the maximum and residual hydropower potential of the basin for a horizon of 30 yr (i.e. year 2040. Current hydropower production is estimated based on historical available data, while future energy production is deduced from the available water in the catchment (estimated based on measured hydrographs of the past years, whereas electricity demand is assessed by correlating existing electricity demand with the estimated population growth and economic development. The maximum and residual hydropower potential of the basin were assessed for the mean annual flows of the present hydrological regime (1970–2000 and topographical characteristics of the area.

    Computations were performed using an integrated GIS environment called VAPIDRO-ASTE released by the Research on Energy System (Italy. The residual hydropower potential of the basin is computed considering first that the water supply needs for population, industry and agriculture are served, and then hydropower energy is produced. The calculated hydropower production is found to be approximately half of the estimated electricity demand, which shows that there is a need to look for other sources of energy in the future.

  4. Contribution of Isotopic Tools to the Numerical Simulation of the Mar del Plata Coastal Aquifer, Argentina

    Energy Technology Data Exchange (ETDEWEB)

    Bocanegra, E.; Martinez, D. E. [Instituto de Geologia de Costas y del Cuaternario, UNMDP (Argentina); Pool, M.; Carrera, J. [Instituto de Diagnostico Ambiental y Estudios del Agua, CSIC (Spain)

    2013-07-15

    Over-exploitation in the coastal aquifer in Mar del Plata, Argentina, led to a seawater intrusion process affecting groundwater by salinization. The aim of this paper is to show the contribution of isotopic techniques to generate the numerical flow and transport model of the Mar del Plata aquifer. On the basis of the hydrogeological conceptual model, a numerical model was constructed. It consists of a multilayer aquifer in the urban area with 2 layers separated by an aquitard and a monolayer aquifer in the rest of the basin. The isotopic difference recorded in groundwaters allow the identification of the origin of the recharge and the confirmation of the presence of the hydrogeological environments incorporated in the numerical model. Flow simulation reflects the evolution of piezometric heads. Chloride transport simulation represents the salinization process due to seawater intrusion and the subsequent backward movement of the interface due to the abandonment of salinized wells. The results of numerical simulation confirm the conceptual model and reproduce the impact of the adopted management strategies. (author)

  5. Assessing residual hydropower potential of the La Plata Basin accounting for future user demands

    Science.gov (United States)

    Popescu, I.; Brandimarte, L.; Perera, M. S. U.; Peviani, M.

    2012-08-01

    La Plata Basin is shared by five countries (Argentina, Bolivia, Brazil, Paraguay and Uruguay), which have fast growing economies in South America. These countries need energy for their sustainable development; hence, hydropower can play a very important role as a renewable clean source of energy. This paper presents an analysis of the current hydropower production and electricity demand in La Plata Basin (LPB), and it analyses the maximum and residual hydropower potential of the basin for a horizon of 30 yr (i.e. year 2040). Current hydropower production is estimated based on historical available data, while future energy production is deduced from the available water in the catchment (estimated based on measured hydrographs of the past years), whereas electricity demand is assessed by correlating existing electricity demand with the estimated population growth and economic development. The maximum and residual hydropower potential of the basin were assessed for the mean annual flows of the present hydrological regime (1970-2000) and topographical characteristics of the area. Computations were performed using an integrated GIS environment called VAPIDRO-ASTE released by the Research on Energy System (Italy). The residual hydropower potential of the basin is computed considering first that the water supply needs for population, industry and agriculture are served, and then hydropower energy is produced. The calculated hydropower production is found to be approximately half of the estimated electricity demand, which shows that there is a need to look for other sources of energy in the future.

  6. Main findings

    International Nuclear Information System (INIS)

    2014-01-01

    Licensing regimes vary from country to country. When the license regime involves several regulators and several licenses, this may lead to complex situations. Identifying a leading organisation in charge of overall coordination including preparation of the licensing decision is a useful practice. Also, if a stepwise licensing process is implemented, it is important to fix in legislation decisions and/or time points and to identify the relevant actors. There is considerable experience in civil and mining engineering that can be applied when constructing a deep geological disposal facility. Specific challenges are, however, the minimization of disturbances to the host rock and the understanding of its long-term behavior. Construction activities may affect the geo-hydraulic and geochemical properties of the various system components which are important safety features of the repository system. Clearly defined technical specifications and an effective quality management plan are important in ensuring successful repository implementation which is consistent with safety requirements. Monitoring plan should also be defined in advance. The regulatory organization should prepare itself to the licensing review before construction by allocating sufficient resources. It should increase its competence, e.g., by interacting early with the implementer and through its own R and D. This will allow the regulator to define appropriate technical conditions associated to the construction license and to elaborate a relevant inspection plan of the construction work. After construction, obtaining the operational license is the most important and crucial step. Main challenges include (a) establishing sufficient confidence so that the methods for closing the individual disposal units comply with the safety objectives and (b) addressing the issue of ageing of materials during a 50-100 years operational period. This latter challenge is amplified when reversibility/retrievability is required

  7. Collaborative Potential between National Estuary Programs ...

    Science.gov (United States)

    Estuaries are among the most productive ecosystems in the world, providing unique habitat for freshwater and marine species as well as valuable social and economic benefits. The wealth of ecosystem goods and services from estuaries has led to growth and development of human communities in adjacent areas and an increase in human activities that can adversely affect water quality and critical habitat. Managing for sustainable estuaries requires a balance of environmental concerns with community social and economic values. This has created an opportunity to leverage Environmental Protection Agency (EPA) scientific knowledge and tools with National Estuary Program (NEP) planning and management expertise to address environmental challenges in important estuarine ecosystems. The non-regulatory National Estuary Program (NEP) was outlined in the Clean Water Act to provide stakeholders an opportunity to monitor and manage ‘nationally significant’ estuaries. Currently there are 28 estuaries in the NEP, broadly distributed across the Atlantic, Pacific and Gulf Coasts, and in Puerto Rico. The local NEP management conferences must address a variety of environmental issues, from water quality and natural resources to coastal and watershed development. While the underlying objectives of each NEP are quite similar, each has unique landscapes, land uses, waterbodies, habitats, biological resources, economies and social culture. Consequently, the effects and severity of anthr

  8. Impact of intertidal area characteristics on estuarine tidal hydrodynamics: A modelling study for the Scheldt Estuary

    Science.gov (United States)

    Stark, J.; Smolders, S.; Meire, P.; Temmerman, S.

    2017-11-01

    Marsh restoration projects are nowadays being implemented as ecosystem-based strategies to reduce flood risks and to restore intertidal habitat along estuaries. Changes in estuarine tidal hydrodynamics are expected along with such intertidal area changes. A validated hydrodynamic model of the Scheldt Estuary is used to gain fundamental insights in the role of intertidal area characteristics on tidal hydrodynamics and tidal asymmetry in particular through several geomorphological scenarios in which intertidal area elevation and location along the estuary is varied. Model results indicate that the location of intertidal areas and their storage volume relative to the local tidal prism determine the intensity and reach along the estuary over which tidal hydrodynamics are affected. Our model results also suggest that intertidal storage areas that are located within the main estuarine channel system, and hence are part of the flow-carrying part of the estuary, may affect tidal hydrodynamics differently than intertidal areas that are side-basins of the main estuarine channel, and hence only contribute little to the flow-carrying cross-section of the estuary. If tidal flats contribute to the channel cross-section and exert frictional effects on the tidal propagation, the elevation of intertidal flats influences the magnitude and direction of tidal asymmetry along estuarine channels. Ebb-dominance is most strongly enhanced if tidal flats are around mean sea level or slightly above. Conversely, flood-dominance is enhanced if the tidal flats are situated low in the tidal frame. For intertidal storage areas at specific locations besides the main channel, flood-dominance in the estuary channel peaks in the vicinity of those areas and generally reduces upstream and downstream compared to a reference scenario. Finally, the model results indicate an along-estuary varying impact on the tidal prism as a result of adding intertidal storage at a specific location. In addition to known

  9. Characterizing seston in the Penobscot River Estuary.

    Science.gov (United States)

    Meseck, Shannon L; Li, Yaqin; Sunila, Inke; Dixon, Mark; Clark, Paul; Lipsky, Christine; Stevens, Justin R; Music, Paul; Wikfors, Gary H

    2017-10-01

    The Penobscot River Estuary is an important system for diadromous fish in the Northeast United States of American (USA), in part because it is home to the largest remnant population of Atlantic salmon, Salmo salar, in the country. Little is known about the chemical and biological characteristics of seston in the Penobscot River Estuary. This study used estuarine transects to characterize the seston during the spring when river discharge is high and diadromous fish migration peaks in the Penobscot River Estuary. To characterize the seston, samples were taken in spring 2015 for phytoplankton identification, total suspended matter (TSM), percent organic TSM, chlorophyll a, particle size (2 μm-180 μm), particulate carbon and nitrogen concentrations, and stable carbon and nitrogen isotopes. The estuarine profiles indicate that TSM behaved non-conservatively with a net gain in the estuary. As phytoplankton constituted only 1/1000 of the particles, the non-conservative behavior of TSM observed in the estuary was most likely not attributable to phytoplankton. Particulate carbon and nitrogen ratios and stable isotope signals indicate a strong terrestrial, allochthonous signal. The seston in the Penobscot River Estuary was dominated by non-detrital particles. During a short, two-week time period, Heterosigma akashiwo, a phytoplankton species toxic to finfish, also was detected in the estuary. A limited number of fish samples, taken after the 2015 Penobscot River Estuary bloom of H. akashiwo, indicated frequent pathological gill damage. The composition of seston, along with ichthyotoxic algae, suggest the need for further research into possible effects upon resident and migratory fish in the Penobscot River Estuary. Published by Elsevier Ltd.

  10. DEPORTE, SOCIABILIDAD Y PARTICIPACIÓN POLÍTICA ENTRE NADADORES “MASTER” DEL CLUB UNIDOS DE LA PLATA / Sport, sociability and political participation among master swimmers of Club Unidos de La Plata

    Directory of Open Access Journals (Sweden)

    Julia Hang

    2014-12-01

    Full Text Available El presente trabajo se propone analizar las diversas maneras en que se establecen relaciones sociales y políticas partir de una práctica deportiva.  Se tomará el caso de un conjunto de nadadores “master” (adultos del Club Unidos de La Plata[1], quienes desde el año 2008 participan de la conducción política de la institución, para dar cuenta del modo en que se relacionan entre sí y con la política institucional del club, otorgando sentidos específicos a su participación “política”. Dado que la práctica de la natación es valorada por estos actores no sólo por su dimensión deportiva, sino principalmente por su dimensión sociable, aquí se buscará reflexionar sobre los modos en que a partir de la participación en una actividad deportiva y sociable, actores con diferentes historias y trayectorias políticas se vinculan entre sí, construyen relaciones políticas y disputan espacios de poder, tales como la presidencia del club o un lugar en la comisión directiva. A su vez, se buscará reflexionar sobre el vínculo que hubiera entre estas relaciones y otras esferas de la política local, considerando las apuestas subjetivas y los sentidos otorgados por los actores a la participación en este espacio.   Palabras Clave: deporte, sociabilidad, política, club, natación.   Abstract This paper analyzes the ways in which social and political relations are established from a sport. It will take the case of a group of "master" swimmers (adults of Club Unidos de La Plata , who since the 2008 year take part of the political leadership of the institution , to show the way they relate between each other and the institutional politics, giving specific senses to their participation in "politics" . Since the practice of swimming is valued by these actors not only for its sportive dimension , but mainly for its social dimension , here we seek to reflect on the ways from participating in a sportive and sociable practice , actors with

  11. Discontinuous Galerkin modeling of the Columbia River's coupled estuary-plume dynamics

    Science.gov (United States)

    Vallaeys, Valentin; Kärnä, Tuomas; Delandmeter, Philippe; Lambrechts, Jonathan; Baptista, António M.; Deleersnijder, Eric; Hanert, Emmanuel

    2018-04-01

    The Columbia River (CR) estuary is characterized by high river discharge and strong tides that generate high velocity flows and sharp density gradients. Its dynamics strongly affects the coastal ocean circulation. Tidal straining in turn modulates the stratification in the estuary. Simulating the hydrodynamics of the CR estuary and plume therefore requires a multi-scale model as both shelf and estuarine circulations are coupled. Such a model has to keep numerical dissipation as low as possible in order to correctly represent the plume propagation and the salinity intrusion in the estuary. Here, we show that the 3D baroclinic discontinuous Galerkin finite element model SLIM 3D is able to reproduce the main features of the CR estuary-to-ocean continuum. We introduce new vertical discretization and mode splitting that allow us to model a region characterized by complex bathymetry and sharp density and velocity gradients. Our model takes into account the major forcings, i.e. tides, surface wind stress and river discharge, on a single multi-scale grid. The simulation period covers the end of spring-early summer of 2006, a period of high river flow and strong changes in the wind regime. SLIM 3D is validated with in-situ data on the shelf and at multiple locations in the estuary and compared with an operational implementation of SELFE. The model skill in the estuary and on the shelf indicate that SLIM 3D is able to reproduce the key processes driving the river plume dynamics, such as the occurrence of bidirectional plumes or reversals of the inner shelf coastal currents.

  12. Seasonal distribution and interactions between plankton and microplastics in a tropical estuary

    Science.gov (United States)

    Lima, A. R. A.; Barletta, M.; Costa, M. F.

    2015-11-01

    The seasonal migration of a salt wedge and rainfall were the major factors influencing the spatiotemporal distribution of ichthyoplankton and microplastics along the main channel of the Goiana Estuary, NE Brazil. The most abundant taxa were the clupeids Rhinosardinia bahiensis and Harengula clupeola, followed by the achirid Trinectes maculatus (78.7% of the catch). Estuarine and mangrove larvae (e.g. Anchovia clupeoides, Gobionellus oceanicus), as well as microplastics were ubiquitous. During drier months, the salt wedge reaches the upper estuary and marine larvae (e.g. Cynoscion acoupa) migrated upstream until the zones of coastal waters influence. However, the meeting of waterfronts in the middle estuary forms a barrier that retains the microplastics in the upper and lower estuary most part of the year. During the late dry season, a bloom of zooplankton was followed by a bloom of fish larvae (12.74 ind. 100 m-3) and fish eggs (14.65 ind. 100 m-3) at the lower estuary. During the late rainy season, the high freshwater inflow flushed microplastics, together with the biota, seaward. During this season, a microplastic maximum (14 items 100 m-3) was observed, followed by fish larvae maximum (14.23 ind. 100 m-3) in the lower estuary. In contrast to fish larvae, microplastics presented positive correlation with high rainfall rates, being more strictly associated to flushing out/into the estuary than to seasonal variation in environmental variables. Microplastics represented half of fish larvae density. Comparable densities in the water column increase the chances of interaction between microplastics and fish larvae, including the ingestion of smaller fragments, whose shape and colour are similar to zooplankton prey.

  13. Tidal and spatial variability of nitrous oxide (N2O) in Sado estuary (Portugal)

    Science.gov (United States)

    Gonçalves, Célia; Brogueira, Maria José; Nogueira, Marta

    2015-12-01

    The estimate of the nitrous oxide (N2O) fluxes is fundamental to assess its impact on global warming. The tidal and spatial variability of N2O and the air-sea fluxes in the Sado estuary in July/August 2007 are examined. Measurements of N2O and other relevant environmental parameters (temperature, salinity, dissolved oxygen and dissolved inorganic nitrogen - nitrate plus nitrite and ammonium) were recorded during two diurnal tidal cycles performed in the Bay and Marateca region and along the estuary during ebb, at spring tide. N2O presented tidal and spatial variability and varied spatially from 5.0 nmol L-1 in Marateca region to 12.5 nmol L-1 in Sado river input. Although the Sado river may constitute a considerable N2O source to the estuary, the respective chemical signal discharge was rapidly lost in the main body of the estuary due to the low river flow during the sampling period. N2O varied with tide similarly between 5.2 nmol L-1 (Marateca) and 10.0 nmol L-1 (Sado Bay), with the maximum value reached two hours after flooding period. The influence of N2O enriched upwelled seawater (˜10.0 nmol L-1) was well visible in the estuary mouth and apparently represented an important contribution of N2O in the main body of Sado estuary. Despite the high water column oxygen saturation in most of Sado estuary, nitrification did not seem a relevant process for N2O production, probably as the concentration of the substrate, NH4+, was not adequate for this process to occur. Most of the estuary functioned as a N2O source, and only Marateca zone has acted as N2O sink. The N2O emission from Sado estuary was estimated to be 3.7 Mg N-N2O yr-1 (FC96) (4.4 Mg N-N2O yr-1, FRC01). These results have implications for future sampling and scaling strategies for estimating greenhouse gases (GHGs) fluxes in tidal ecosystems.

  14. Birds of Mahi River estuary, Gujarat, India

    Directory of Open Access Journals (Sweden)

    P.J. Pandya

    2010-06-01

    Full Text Available The Mahi river estuary is one of the major estuaries of Gujarat. This paper presents a comprehensive list of birds of the Mahi river estuary (nearly 50 km stretch and the adjacent banks/ravines and defines the avian diversity at three major estuarine gradations with a brief check of similarity and diversity within the three. The present observation is the outcome of a 3 year period from August 2006 to July 2009. A sum total of 118 species belonging to 42 families were reported and listed as on Upstream, Midstream, and Downstream of estuary. No significant difference was seen in the species richness at the three zones; a change in avian composition at upstream and downstream was notable.

  15. Climate Ready Estuaries Partner Projects Map

    Science.gov (United States)

    CRE partners with the National Estuary Program to develop climate change projects in coastal U.S. areas, such as bays and harbors; to develop adaptation action plans, identify climate impacts and indicators, and more. This map shows project locations.

  16. National Estuary Program Study Area Boundaries

    Data.gov (United States)

    U.S. Environmental Protection Agency — There are 28 National Estuary Programs (NEPs) in the U.S.that implement habitat protection and restoration projects with their partners. This work takes place within...

  17. Mercury enrichment in sediments of Amba estuary

    Digital Repository Service at National Institute of Oceanography (India)

    Ram, A.; Rokade, M.A.; Zingde, M.D.

    of anthropogenic metal to the estuary. Geoaccumulation index and enrichment factor support Hg contamination of the estuarine sediment to a varying degree. Hg is not significantly correlated with TOC, Al, Fe and Mn in these sediments...

  18. Heavy metals in Mindhola river estuary, India

    Digital Repository Service at National Institute of Oceanography (India)

    Zingde, M.D.; Rokade, M.A; Mandalia, A

    The heavy metal concentrations are studied along the Mindhola river estuary. Surface and bottom water samples were collected using Niskin Sampler. The sediment samples were collected using a Van Veen grab. The heavy metal concentration is estimated...

  19. Mercury in sediments of Ulhas estuary

    Digital Repository Service at National Institute of Oceanography (India)

    Ram, A.; Rokade, M.A.; Borole, D.V.; Zingde, M.D.

    Hg levels in water, suspended particulate matter and sediment of the Ulhas estuary are under considerable environmental stress due to the indiscriminate release of effluents from a variety of industries including chlor-alkali plants. Concentration...

  20. Benthic studies in south Gujarat estuaries

    Digital Repository Service at National Institute of Oceanography (India)

    Govindan, K.; Varshney, P.K.; Desai, B.N.

    Benthic biomass and faunal composition in relation to various environmental conditions of the four South Gujarat estuaries namely the Auranga, Ambika, Purna and Mindola were studied and compared. Mean population density of benthos in Auranga, Ambika...

  1. Distribution, sources and ecological risk assessment of PAHs in surface sediments from the Luan River Estuary, China.

    Science.gov (United States)

    Zhang, Daolai; Liu, Jinqing; Jiang, Xuejun; Cao, Ke; Yin, Ping; Zhang, Xunhua

    2016-01-15

    The distribution, sources and risk assessment of 16 polycyclic aromatic hydrocarbons (PAHs) of surface sediments in the Luan River Estuary, China, have been investigated in the research. The results indicated that the total concentrations of 16 PAHs in surface sediments of the Luan River Estuary ranged from 5.1 to 545.1 ng g(-1)dw with a mean value of 120.8 ng g(-1)dw, which is relatively low in comparison with other estuaries around the world. The PAHs in the study area were mainly originated from pyrogenic sources. Besides, PAHs may be contaminated by petrogenic PAHs as indicated by the selected ratios of PAHs, the 2-tailed Pearson correlation analysis and principal components analysis at different sites. The result of the ecological risk assessment shows little negative effect for most individual PAHs in surface sediments of the Luan River Estuary, China. Copyright © 2015 Elsevier Ltd. All rights reserved.

  2. Estuaries.

    Science.gov (United States)

    Awkerman, Gary L.

    This publication is designed for use in standard science curricula to develop oceanologic manifestations of certain science topics. Included are teacher guides, student activities, and demonstrations designed to impart ocean understanding to high school students. When the student has completed this unit, he should be able to: (1) define an…

  3. Evaluación de la vulnerabilidad socio-ambiental del periurbano de Mar del Plata

    Directory of Open Access Journals (Sweden)

    Daiana Daga

    2015-12-01

    Full Text Available RESUMEN El periurbano de Mar del Plata conforma un espacio dinámico y heterogéneo, susceptible a distintas intervenciones que pueden generar impactos ambientales con consecuencias negativas sobre la población expuesta. El presente trabajo evalúa la vulnerabilidad socio-ambiental del periurbano marplatense en 2010, distinguiendo sectores críticos y principales aspectos que determinan las condiciones extremas. Para ello se construyó un Índice de Vulnerabilidad Socio-Ambiental (IVSA y se examinó su distribución espacial.La vulnerabilidad socio-ambiental hace referencia a las condiciones de la población y su entorno inmediato para enfrentar efectos adversos. Las situaciones más críticas (IVSA= 0,46–0,58 pertenecen a los sectores del periurbano definidos por los ejes que conforman las Rutas Nº 226 y Nº 88. Las dimensiones sanitaria, educativa y ambiental determinan en mayor medida la distribución del IVSA. El procedimiento metodológico empleado permitió identificar áreas críticas, siendo transferible a otras situaciones con problemáticas semejantes. ABSTRACT Mar del Plata peri-urban conforms a heterogeneous and dynamic space, susceptible to many interventions that generate significant impacts with negative consequences on the exposed population. This paper evaluates the socio-environmental vulnerability of the Mar del Plata peri-urban in 2010, distinguishing critical sectors and principle aspects that determine the extreme conditions. To this end, it was built a Socio-Environmental Vulnerability Index (SEVI and its spatial distribution was examined. The socio-environmental vulnerability refers to the conditions of the population and their environment to deal with adverse effects. The most critical situations (SEVI= 0.46-0.58 belongs to the peri-urban sectors that were defined by the 226 and 88 roads. The health, education and environmental dimensions determine the SEVI distribution. The methodological procedure employed allowed

  4. Estudio de la climatología y la hidrología de la Cuenca del Plata en un conjunto de modelos climáticos globales Study of the La Plata Basin climatology and hydrology in a set of global climate models

    Directory of Open Access Journals (Sweden)

    Ramiro Saurral

    2009-06-01

    Full Text Available La Cuenca del Plata provee de agua potable a millones de personas a través de cinco países en Sudamérica. En el contexto de un potencial cambio futuro en las condiciones medias del clima, los caudales de los ríos de la cuenca podrían verse afectados y en este sentido es de sumo interés poder inferir estos posibles cambios en los caudales para década venideras. El objetivo de este trabajo es determinar la habilidad de tres modelos climáticos globales (CNRM-CM3, ECHAM5-MPI/OM y GFDL-CM2.0 en simular los caudales observados de los principales ríos de la Cuenca del Plata. Para ello, se emplearon las salidas de precipitación y temperatura de esos modelos climáticos para forzar un modelo hidrológico distribuido durante la última década del siglo XX (1990- 1999. Los resultados muestran que los tres modelos presentan serias deficiencias en la representación del ciclo hidrológico y que esas diferencias están principalmente explicadas por los importantes errores que tienen en los patrones de precipitación y temperatura sobre el sur de Sudamérica. Esto determina un fuerte impedimento al potencial uso que se podría dar a estos modelos para inferir posibles cambios futuros en los caudales de los ríos de la región.Hydrological modeling is a potent tool that can be useful to, among other things, determine the potential future availability of fresh water on Earth. In particular, the La Plata Basin supplies fresh water to millions of people across five countries. In a context of possible future changes on climate, river streamflows could be affected and in this sense it is of crucial importance to infer these potential changes for the upcoming decades. The objective of this paper is to determine the ability of three climate models (CNRM-CM3, ECHAM5-MPI/OM and GFDL-CM2.0 to simulate the observed discharges of the main La Plata Basin rivers. To force the distributed hydrology model, climate models output data included daily minimum and

  5. Keurbooms Estuary floods and sedimentation

    Directory of Open Access Journals (Sweden)

    Eckart H. Schumann

    2015-11-01

    Full Text Available The Keurbooms Estuary at Plettenberg Bay lies on a wave-dominated, microtidal coast. It has a dune-topped sandy barrier, or barrier dune, almost 4 km long, with a narrow back-barrier lagoon connected to its source rivers, the Keurbooms and Bitou. The estuary exits to the sea through this barrier dune, and it is the geomorphology and mouth position in relation to floods, which is the subject of this paper. Measurements of rainfall, water level, waves and high- and low-tide water lines were used to analyse the mouth variability over the years 2006–2012. Two major floods occurred during this time, with the first in November 2007 eroding away more than 500 000 m3 of sediment. The new mouth was established at the Lookout Rocks limit – the first time since 1915. The second flood occurred in July 2012 and opened up a new mouth about 1 km to the north-east; high waves also affected the position of the breach. The mouth has a tendency to migrate southwards against the longshore drift, but at any stage this movement can be augmented or reversed. The effectiveness of floods in breaching a new mouth through the barrier dune depends on the flood size and the nature of the exit channel in the back-barrier lagoon. Other factors such as ocean waves, sea level, vegetative state of the dune and duration of the flood are also important and can determine where the breach occurs, and if the new mouth will dominate the old mouth.

  6. Bar dimensions and bar shapes in estuaries

    Science.gov (United States)

    Leuven, Jasper; Kleinhans, Maarten; Weisscher, Steven; van der Vegt, Maarten

    2016-04-01

    Estuaries cause fascinating patterns of dynamic channels and shoals. Intertidal sandbars are valuable habitats, whilst channels provide access to harbors. We still lack a full explanation and classification scheme for the shapes and dimensions of bar patterns in natural estuaries, in contrast with bars in rivers. Analytical physics-based models suggest that bar length in estuaries increases with flow velocity, tidal excursion length or estuary width, depending on which model. However, these hypotheses were never validated for lack of data and experiments. We present a large dataset and determine the controls on bar shape and dimensions in estuaries, spanning bar lengths from centimeters (experiments) to 10s of kilometers length. First, we visually identified and classified 190 bars, measured their dimensions (width, length, height) and local braiding index. Data on estuarine geometry and tidal characteristics were obtained from governmental databases and literature on case studies. We found that many complex bars can be seen as simple elongated bars partly cut by mutually evasive ebb- and flood-dominated channels. Data analysis shows that bar dimensions scale with estuary dimensions, in particular estuary width. Breaking up the complex bars in simple bars greatly reduced scatter. Analytical bar theory overpredicts bar dimensions by an order of magnitude in case of small estuarine systems. Likewise, braiding index depends on local width-to-depth ratio, as was previously found for river systems. Our results suggest that estuary dimensions determine the order of magnitude of bar dimensions, while tidal characteristics modify this. We will continue to model bars numerically and experimentally. Our dataset on tidal bars enables future studies on the sedimentary architecture of geologically complex tidal deposits and enables studying effects of man-induced perturbations such as dredging and dumping on bar and channel patterns and habitats.

  7. Alien reef-building polychaete drives long-term changes in invertebrate biomass and diversity in a small, urban estuary

    Science.gov (United States)

    McQuaid, K. A.; Griffiths, C. L.

    2014-02-01

    Two of the greatest threats to native biodiversity are the construction of artificial structures in natural environments and the introduction of invasive species. As the development and urbanisation of estuaries continues at an increasing rate worldwide, these environments are being simultaneously affected by these threats. This study quantifies the spread of an invasive reef-building polychaete, Ficopomatus enigmaticus, in a small, highly manipulated urban estuary in South Africa and investigates its role as an ecosystem engineer. Anthropogenic changes to the Zandvlei Estuary, including construction of a rubble weir and canalisation near the estuary mouth, construction of an extensive marina development and hardening of the banks with concrete, have facilitated the expansion of F. enigmaticus. The standing stock of F. enigmaticus increased from 13.69 t, as measured in 1986, to 50.03 t in 2012, due both to increase in the total area colonised and standing stock per m2. Since F. enigmaticus reefs support a greater biomass of infauna than adjacent sandy areas, total invertebrate biomass in the estuary is estimated to have increased from less than 0.30 t in 1942, to over 56.80 t in 2012, due mainly to hardening of banks in parts of the main estuary with concrete and construction of a marina system. A positive correlation between reef mass and infaunal biomass, density and diversity was also found.

  8. Recruitment success and growth variability of mugilids in a West African estuary impacted by climate change

    Science.gov (United States)

    Trape, S.; Durand, J.-D.; Vigliola, L.; Panfili, J.

    2017-11-01

    With the persistence of a drought since the late 1960s, some West African estuaries became permanently reversed in term of salinity gradient and hypersaline waters are present in their upstream part (salinity >60). To understand the mechanisms regulating fish recruitment intensity in these estuaries and evaluate the consequences of freshwater shortages on juvenile habitat quality, a growth study was conducted in the Saloum hypersaline estuary (Senegal). The Mugilidae fish family, highly representative of estuarine environments, was targeted and several species sampled (Chelon dumerili, Mugil bananensis and M. cf. curema sp. M). Juveniles were sampled monthly all the year round in three areas of the estuary exhibiting strongly contrasted habitat conditions. Otolith sections were used to estimate the ages, reconstruct growth trajectories, estimate the duration of the oceanic larval phase, and evaluate juvenile growth variability along the salinity gradient. Analyses revealed that the temporal recruitment variability of C. dumerili, with 2 annual cohorts, was not mainly induced by growth-selection mechanisms, but probably more by predation pressures. Juveniles exhibited significantly faster growth rates in the lower salinity suggesting that benthic food availability was a strong factor controlling habitat quality of early juveniles. Salinity had also a clear impact when reducing the growth in hypersaline conditions and/or selecting slower growing individuals. Moderate freshwater inputs positively affected the nursery function of the estuary for mugilids by enhancing the productivity of the first trophic levels. In a long term, the global change could have an impact of the mugilid fishery and its management.

  9. Factors governing the pH in a heterotrophic, turbid, tidal estuary

    NARCIS (Netherlands)

    Hofmann, A.F.; Meysman, F.J.R.; Soetaert, K.; Middelburg, J.J.

    2009-01-01

    A method to quantify the influence of kinetically modelled biogeochemical processes on the pH of an ecosystem with time variable acid-base dissociation constants is presented and applied to the heterotrophic, turbid Scheldt estuary (SW Netherlands, N Belgium). Nitrification is identified as the main

  10. Haemocytic leukemia in Prince Edward Island (PEI) soft shell clam (Mya arenaria): Spatial distribution in agriculturally impacted estuaries

    International Nuclear Information System (INIS)

    Muttray, Annette; Reinisch, Carol; Miller, Jason; Ernst, William; Gillis, Patricia; Losier, Melanie; Sherry, James

    2012-01-01

    Intensive farming of potatoes in Prince Edward Island (PEI) relies on the repeated and widespread application of fertilizers and pesticides. In PEI the main potato farming areas are in close proximity and drain directly to estuaries. Runoff from high agricultural activity watersheds could impact benthic organism health in the depositional zone of downstream estuaries. The estuarine filter feeder Mya arenaria (soft-shell clam) could be particularly vulnerable to both particle-adsorbed and water soluble contaminants. M. arenaria is susceptible to haemocytic leukemia. In May 2009, we established that heavily proliferated leukemia (HPL) prevalence was generally higher in PEI estuaries located downstream of high intensity potato farming (Dunk and Wilmot estuaries) watersheds than in estuaries downstream of lower intensity areas. Using Mab-1E10 based immunocytochemistry we observed that leukemic haemocytes from the Dunk and Wilmot estuaries were 1E10 negative whereas those from the Ox/Sheep estuary (low potato farming intensity) were 1E10 positive. The expression of genes in the p53 tumour suppressor pathway enabled us to differentiate groups of leukemic and normal M. arenaria, validating our diagnoses. In October 2009, we confirmed that HPL prevalence was elevated in the Dunk and Wilmot estuaries compared to reference (Souris River). Moreover, leukemia prevalence declined with distance from the river mouths along transects through the Dunk and Wilmot estuaries. The pesticides ß-endosulfan and α-endosulfan were detected in surface sediments from the Dunk and Wilmot estuaries, but not in sediments from either the Souris River or several other lower intensity potato farming watersheds. Our study provides evidence of an association between intensity of potato farming and prevalence of clam leukemia at downstream estuaries in PEI. - Highlights: ► We examined leukemia prevalence in PEI clams Mya arenaria. ► Prevalence was generally higher downstream of high intensity

  11. Haemocytic leukemia in Prince Edward Island (PEI) soft shell clam (Mya arenaria): Spatial distribution in agriculturally impacted estuaries

    Energy Technology Data Exchange (ETDEWEB)

    Muttray, Annette, E-mail: amuttray@rescan.com [Environment Canada, Water Science and Technology Directorate, 867 Lakeshore Road, Burlington, ON, Canada L7R 4A6 (Canada); Reinisch, Carol, E-mail: creinisch@mbl.edu [Visiting Scientist Environment Canada, Water Science and Technology Directorate, 867 Lakeshore Road, Burlington, ON, Canada L7R 4A6 (Canada); Miller, Jason, E-mail: j.miller@ec.gc.ca [Environment Canada, Water Science and Technology Directorate, 867 Lakeshore Road, Burlington, ON, Canada L7R 4A6 (Canada); Ernst, William, E-mail: bill.ernst@ec.gc.ca [Environment Canada, Water Science and Technology Directorate, 45 Alderney Drive, Dartmouth, NS, Canada B2Y 2N6 (Canada); Gillis, Patricia, E-mail: patty.gillis@ec.gc.ca [Environment Canada, Water Science and Technology Directorate, 867 Lakeshore Road, Burlington, ON, Canada L7R 4A6 (Canada); Losier, Melanie, E-mail: melanie.losier@ec.gc.ca [Environment Canada, Atlantic Laboratory for Environmental Testing, Environmental Science Centre, P.O. Box 23005 Moncton, NB, Canada E1A 6S8 (Canada); Sherry, James, E-mail: jim.sherry@ec.gc.ca [Environment Canada, Water Science and Technology Directorate, 867 Lakeshore Road, Burlington, ON, Canada L7R 4A6 (Canada)

    2012-05-01

    Intensive farming of potatoes in Prince Edward Island (PEI) relies on the repeated and widespread application of fertilizers and pesticides. In PEI the main potato farming areas are in close proximity and drain directly to estuaries. Runoff from high agricultural activity watersheds could impact benthic organism health in the depositional zone of downstream estuaries. The estuarine filter feeder Mya arenaria (soft-shell clam) could be particularly vulnerable to both particle-adsorbed and water soluble contaminants. M. arenaria is susceptible to haemocytic leukemia. In May 2009, we established that heavily proliferated leukemia (HPL) prevalence was generally higher in PEI estuaries located downstream of high intensity potato farming (Dunk and Wilmot estuaries) watersheds than in estuaries downstream of lower intensity areas. Using Mab-1E10 based immunocytochemistry we observed that leukemic haemocytes from the Dunk and Wilmot estuaries were 1E10 negative whereas those from the Ox/Sheep estuary (low potato farming intensity) were 1E10 positive. The expression of genes in the p53 tumour suppressor pathway enabled us to differentiate groups of leukemic and normal M. arenaria, validating our diagnoses. In October 2009, we confirmed that HPL prevalence was elevated in the Dunk and Wilmot estuaries compared to reference (Souris River). Moreover, leukemia prevalence declined with distance from the river mouths along transects through the Dunk and Wilmot estuaries. The pesticides ss-endosulfan and {alpha}-endosulfan were detected in surface sediments from the Dunk and Wilmot estuaries, but not in sediments from either the Souris River or several other lower intensity potato farming watersheds. Our study provides evidence of an association between intensity of potato farming and prevalence of clam leukemia at downstream estuaries in PEI. - Highlights: Black-Right-Pointing-Pointer We examined leukemia prevalence in PEI clams Mya arenaria. Black

  12. Effects of urbanisation on macroalgae and sessile invertebrates in southeast Australian estuaries

    Science.gov (United States)

    Fowles, Amelia E.; Stuart-Smith, Rick D.; Stuart-Smith, Jemina F.; Hill, Nicole A.; Kirkpatrick, Jamie B.; Edgar, Graham J.

    2018-05-01

    The influence of anthropogenic and environmental factors on the composition, cover and dominance of macroalgae and sessile invertebrates was assessed in three capital city estuaries in south-eastern Australia. Heavy metals and proximity to ports showed the strongest relationships to the distribution of sessile reef biota after accounting for natural environmental gradients. The densities of laminarian, fucoid, brown and red foliose algae were negatively correlated with heavy metals, both in Port Phillip Bay (Melbourne) and the Derwent (Hobart), while turf, filamentous algae and some invertebrates were favoured. Sydney Harbour possessed a different pattern, with the laminarian kelp Ecklonia radiata most abundant near the main shipping port, probably because of biotic interactions involving urchin grazing in the lower estuary. Identifying drivers of benthic community pattern represents a key challenge for effective conservation management, particularly for estuaries affected by multiple anthropogenic impacts.

  13. Updates since Brown v. Plata: alternative solutions for prison overcrowding in California.

    Science.gov (United States)

    Horne, Christopher; Newman, William J

    2015-03-01

    With the number of inmates under the care of the California Department of Corrections and Rehabilitation (CDCR) swelling over the past few decades, California faces a challenge. The U.S. Supreme Court ruled in their 2011 decision in Brown v. Plata that overcrowding violates inmates' Eighth Amendment rights, specifically that they are denied adequate medical and mental health care. Federally mandated release programs have historically raised some concerns regarding public safety and fiscal efficiency. Given the large number of mentally ill inmates in the United States, alternatives such as assisted outpatient treatment, mental health courts, and increased funding for substance use treatment can be used proactively to reduce the CDCR population and provide long-term solutions to the overcrowding problem. These alternatives have already shown long-term cost savings in addition to reducing the recidivism of individuals involved and would help provide appropriate diversion for mentally ill individuals. © 2015 American Academy of Psychiatry and the Law.

  14. Educación literaria en las novelas de colegios de la "Edad De Plata"

    Directory of Open Access Journals (Sweden)

    Fermín Ezpeleta Aguilar

    2013-12-01

    Full Text Available En un periodo histórico de proliferación de colegios religiosos como es la "Edad de Plata" se consolida en la literatura española el subgénero narrativo de novelas de internado docente. El cotejo de este corpus novelístico aporta claves de investigación acerca de la educación literaria de los escritores y de las generaciones de estudiantes bachilleres de la Restauración, puesto que refleja prácticas de lectura y de escritura, actividades teatrales y canon de lecturas, en un contexto en el que la didáctica de la literatura observa una progresiva sustitución del método retórico por el historicista.

  15. DNA barcoding of odonates from the Upper Plata basin: Database creation and genetic diversity estimation.

    Directory of Open Access Journals (Sweden)

    Ricardo Koroiva

    Full Text Available We present a DNA barcoding study of Neotropical odonates from the Upper Plata basin, Brazil. A total of 38 species were collected in a transition region of "Cerrado" and Atlantic Forest, both regarded as biological hotspots, and 130 cytochrome c oxidase subunit I (COI barcodes were generated for the collected specimens. The distinct gap between intraspecific (0-2% and interspecific variation (15% and above in COI, and resulting separation of Barcode Index Numbers (BIN, allowed for successful identification of specimens in 94% of cases. The 6% fail rate was due to a shared BIN between two separate nominal species. DNA barcoding, based on COI, thus seems to be a reliable and efficient tool for identifying Neotropical odonate specimens down to the species level. These results underscore the utility of DNA barcoding to aid specimen identification in diverse biological hotspots, areas that require urgent action regarding taxonomic surveys and biodiversity conservation.

  16. Seasonal stratification and property distributions in a tropical estuary (Cochin estuary, west coast, India)

    Digital Repository Service at National Institute of Oceanography (India)

    Shivaprasad, A.; Vinita, J.; Revichandran, C.; Reny, P.D.; Deepak, M.P.; Muraleedharan, K.R.; NaveenKumar, K.R.

    immune from extended hypoxia/anoxia and maintaining the health of the Cochin estuary. For the seasonally varying river flow in the estuary, salt intrusion receded with increasing river flow in monsoon and rebounded with decreasing river flow in dry season...

  17. Continental Influence versus marine transition in Rio de la Plata zone - internal continental shelf of the South Atlantic - a multi proxy study

    International Nuclear Information System (INIS)

    Burone, L.; Franco-Fraguas, P.; Garcia-Rodriguez, F.; Venturini, N.; Brugnoli, E.; Muniz, P.; Ortega, L.; Marin, Y.; Mahiques, M.; Nagaic, R.; Bicegoc, M.; Figueiras, R.; Salaroli, A.

    2012-01-01

    The terrigenous proxies contribution, the organic matter origin, the productivity, the hydrodynamic and the biological records were used to determine the imrprint of the continental influence along the Rio de la Plata and the Continental Atlantic

  18. Tropical land-sea couplings: Role of watershed deforestation, mangrove estuary processing, and marine inputs on N fluxes in coastal Pacific Panama.

    Science.gov (United States)

    Valiela, Ivan; Elmstrom, Elizabeth; Lloret, Javier; Stone, Thomas; Camilli, Luis

    2018-07-15

    We review data from coastal Pacific Panama and other tropical coasts with two aims. First, we defined inputs and losses of nitrogen (N) mediating connectivity of watersheds, mangrove estuaries, and coastal sea. N entering watersheds-mainly via N fixation (79-86%)-was largely intercepted; N discharges to mangrove estuaries (3-6%), small compared to N inputs to watersheds, nonetheless significantly supplied N to mangrove estuaries. Inputs to mangrove estuaries (including watershed discharges, and marine inputs during flood tides) were matched by losses (mainly denitrification and export during ebb tides). Mangrove estuary subsidies of coastal marine food webs take place by export of forms of N [DON (62.5%), PN (9.1%), and litter N (12.9%)] that provide dissimilative and assimilative subsidies. N fixation, denitrification, and tidal exchanges were major processes, and DON was major form of N involved in connecting fluxes in and out of mangrove estuaries. Second, we assessed effects of watershed forest cover on connectivity. Decreased watershed forest cover lowered N inputs, interception, and discharge into receiving mangrove estuaries. These imprints of forest cover were erased during transit of N through estuaries, owing to internal N cycle transformations, and differences in relative area of watersheds and estuaries. Largest losses of N consisted of water transport of energy-rich compounds, particularly DON. N losses were similar in magnitude to N inputs from sea, calculated without considering contribution by intermittent coastal upwelling, and hence likely under-estimated. Pacific Panama mangrove estuaries are exposed to major inputs of N from land and sea, which emphasizes the high degree of bi-directional connectivity in these coupled ecosystems. Pacific Panama is still lightly affected by human or global changes. Increased deforestation can be expected, as well as changes in ENSO, which will surely raise watershed-derived loads of N, as well as significantly

  19. [Nutritional status and body composition of poor children in the outlying neighborhoods of La Plata, Argentina].

    Science.gov (United States)

    Oyhenart, Evelia E; Torres, María F; Quintero, Fabián A; Luis, María A; Cesani, María F; Zucchi, Mariel; Orden, Alicia B

    2007-09-01

    To evaluate nutritional status and body composition as indicators of quality of life among poor children served by neighborhood soup kitchens in La Plata, Argentina. From April to November 2004, we conducted a cross-sectional study of 608 healthy children from 1-11 years of age who were being served by two neighborhood soup kitchens in the outlying areas of the city of La Plata. The sample was stratified by age and sex. Height-for-age, weight-for age, and weight-for-height, were measured, as well as BMI, muscle mass and adipose tissue. Z-scores were computed for the data. Odds ratios and the respective 95% confidence intervals were calculated. Prevalence of low weight-for-age was 9%; low weight-for-height, 3%; and low height-for-age, 15%. The prevalence of overweight and obesity were 12.5% and 7.1%, respectively. Among the study sample, 47.2% had low muscle mass and 20.4% had low adipose tissue. Among overweight and obese children, adipose tissue was 34.3% higher than that of the reference population, while muscle mass was 12.5% lower. Undernutrition and obesity are both found among the community of children studied. The high prevalence of delayed growth (i.e., low height-for-age), undernutrition (i.e., low weight-for-age), and the acute lack of muscle mass even among overweight and obese children, seem to be part of the consequences of an inevitable process that unfolds in the face of adverse living conditions.

  20. Nitrogen cycle and ecosystem services in the Brazilian La Plata Basin: anthropogenic influence and climate change

    Directory of Open Access Journals (Sweden)

    M Watanabe

    Full Text Available The increasing human demand for food, raw material and energy has radically modified both the landscape and biogeochemical cycles in many river basins in the world. The interference of human activities on the Biosphere is so significant that it has doubled the amount of reactive nitrogen due to industrial fertiliser production (Haber-Bosch, fossil fuel burning and land-use change over the last century. In this context, the Brazilian La Plata Basin contributes to the alteration of the nitrogen cycle in South America because of its huge agricultural and grazing area that meets the demands of its large urban centres - Sao Paulo, for instance - and also external markets abroad. In this paper, we estimate the current inputs and outputs of anthropogenic nitrogen (in kg N.km-2.yr-1 in the basin. In the results, we observe that soybean plays a very important role in the Brazilian La Plata, since it contributes with an annual entrance of about 1.8 TgN due to biological nitrogen fixation. Moreover, our estimate indicates that the export of soybean products accounts for roughly 1.0 TgN which is greater than the annual nitrogen riverine exports from Brazilian Parana, Paraguay and Uruguay rivers together. Complimentarily, we built future scenarios representing changes in the nitrogen cycle profile considering two scenarios of climate change for 2070-2100 (based on IPCC's A2 and B2 that will affect land-use, nitrogen inputs, and loss of such nutrients in the basin. Finally, we discuss how both scenarios will affect human well-being since there is a connection between nitrogen cycle and ecosystem services that affect local and global populations, such as food and fibre production and climate regulation.

  1. Nitrogen cycle and ecosystem services in the Brazilian La Plata Basin: anthropogenic influence and climate change.

    Science.gov (United States)

    Watanabe, M; Ortega, E; Bergier, I; Silva, J S V

    2012-08-01

    The increasing human demand for food, raw material and energy has radically modified both the landscape and biogeochemical cycles in many river basins in the world. The interference of human activities on the Biosphere is so significant that it has doubled the amount of reactive nitrogen due to industrial fertiliser production (Haber-Bosch), fossil fuel burning and land-use change over the last century. In this context, the Brazilian La Plata Basin contributes to the alteration of the nitrogen cycle in South America because of its huge agricultural and grazing area that meets the demands of its large urban centres - Sao Paulo, for instance - and also external markets abroad. In this paper, we estimate the current inputs and outputs of anthropogenic nitrogen (in kg N.km(-2).yr(-1)) in the basin. In the results, we observe that soybean plays a very important role in the Brazilian La Plata, since it contributes with an annual entrance of about 1.8 TgN due to biological nitrogen fixation. Moreover, our estimate indicates that the export of soybean products accounts for roughly 1.0 TgN which is greater than the annual nitrogen riverine exports from Brazilian Parana, Paraguay and Uruguay rivers together. Complimentarily, we built future scenarios representing changes in the nitrogen cycle profile considering two scenarios of climate change for 2070-2100 (based on IPCC's A2 and B2) that will affect land-use, nitrogen inputs, and loss of such nutrients in the basin. Finally, we discuss how both scenarios will affect human well-being since there is a connection between nitrogen cycle and ecosystem services that affect local and global populations, such as food and fibre production and climate regulation.

  2. Fungal monitoring of the indoor air of the Museo de La Plata Herbarium, Argentina.

    Science.gov (United States)

    Mallo, Andrea C; Elíades, Lorena A; Nitiu, Daniela S; Saparrat, Mario C N

    Biological agents, such as fungal spores in the air in places where scientific collections are stored, can attack and deteriorate them. The aim of this study was to gather information on the indoor air quality of the Herbarium of Vascular Plants of the Museo de Ciencias Naturales de La Plata, Argentina, in relation to fungal propagules and inert particles. This study was made using a volumetric system and two complementary sampling methods: (1) a non-viable method for direct evaluation, and (2) a viable method by culture for viable fungal propagules. The non-viable method led to ten spore morphotypes being found from related fungal sources. A total of 4401.88spores/m 3 and 32135.18 inert suspended particles/m 3 were recorded. The viable method led to the finding of nine fungal taxa as viable spores that mostly belonged to anamorphic forms of Ascomycota, although the pigmented yeast Rhodotorula F.C. Harrison (Basidiomycota) was also found. A total count of 40,500fungal CFU/m 3 air was estimated for all the sites sampled. Both the non-viable and viable sampling methods were necessary to monitor the bio-aerosol load in the La Plata Herbarium. The indoor air of this institution seems to be reasonably adequate for the conservation of vascular plants due to the low indoor/outdoor index, low concentrations of air spores, and/or lack of indicators of moisture problems. Copyright © 2016 Asociación Española de Micología. Publicado por Elsevier España, S.L.U. All rights reserved.

  3. Survey of four marine antifoulant constituents (copper, zinc, diuron and Irgarol 1051) in two UK estuaries.

    Science.gov (United States)

    Comber, S D W; Gardner, M J; Boxall, A B A

    2002-06-01

    A field survey of antifoulant concentrations was undertaken in two UK estuaries (Hamble and Orwell) in 1998 and 1999. The two locations offered variations in physical aspects (Orwell estuary being significantly larger than the Hamble) as well as differences in boat densities (Hamble having almost twice as many vessels moored in the estuary and marinas). Samples were analysed for copper, zinc, diuron and Irgarol 1051, and were collected in summer and winter in order to identify potential seasonal variations in concentrations. The effect that different marina types (e.g. locked marina, one located in a natural inlet and pontooned ones in the open estuary) had on antifoulant concentrations were also investigated. Concentrations of the organic booster biocides, diuron and Irgarol 1051 in the marinas and estuaries were mainly influenced by leaching from antifoulant paints applied to the hulls of leisure craft, and so levels reflected the number of vessels present in the water. As a consequence significantly higher concentrations were found in marinas (up to ca. 900 ng l(-1) for diuron and 240 ng l(-1) for Irgarol 1051) compared with estuaries (up to ca. 400 ng l(-1) for diuron and 100 ng l(-1) for Irgarol 1051) and in summer compared with winter. Sediment concentrations of Irgarol 1051 and diuron were rarely detectable other than in the marinas where high concentrations were detected near slipways assumed to be derived from washed off paint chips. Dissolved concentration profiles for copper and zinc in the estuaries and marinas were different from those for the organic booster biocides partly because other sources of these metals contributed to estuarine and marina loads. In particular, riverine loads and inputs from sacrificial anodes attached to leisure craft, exhibited a major influence of estuarine levels of zinc. Consequently, only in the Hamble estuary for copper was there a clear distinction between summer (typically 3-4 microg l(-1)) and winter dissolved values

  4. U-Pb geochronology of Martín García, Sola, and Dos Hermanas Islands (Argentina and Uruguay): Unveiling Rhyacian, Statherian, Ectasian, and Stenian of a forgotten area of the Río de la Plata Craton

    Science.gov (United States)

    Santos, João O. S.; Chernicoff, Carlos J.; Zappettini, Eduardo O.; McNaughton, Neal J.; Greau, Y.

    2017-12-01

    The Río de la Plata Craton is one of the three major cratons of South America. The craton is largely covered by sedimentary basins where its most exposed area is Buenos Aires-Piedra Alta Province (Chernicoff et al., 2014). This province includes the Martín García Island in the confluence of Uruguay River and the Río de la Plata estuary. Despite to be a reference area for the craton the Martín García Island lacks modern geological investigation. We present U-Pb SIMS (secondary ion mass spectrometer) geochronological data on zircon and titanite, as well as Hf isotope determinations on zircon, from rocks of Martín García Island (Argentina), Sola and Dos Hermanas Islands (Uruguay) and from Paso Severino Formation (Uruguay). We investigated: 1) Rhyacian intermediate-to acidic plutonic, arc-type rocks of the Florida Belt dated between 2090 Ma and 2115 Ma, derived from juvenile Neoarchean crust (TDMHf: 2.52 Ga; average εHf: +3.62); 2) Rhyacian metadacite (San José metamorphic belt) of 2127 Ma; 3) Statherian metagabbros of 1724-1734 Ma, with Transplatense inheritance; 4) Early Ectasian metagabbro of 1392 Ma, with Rhyacian inheritance; and 5) Stenian metagabbros of 1193 Ma (TDMHf: 2.00 Ga, εHf: 0.1). Most of the dated orthogneisses show Brasilian-age (from 778 to 550 Ma) Pb loss in the zircons, interpreted to be caused by shearing or uplifting during Neoproterozoic. The results show that the area is not exclusively Rhyacian in age but encompasses Statherian, Ectasian, and Stenian gabbros. The last two are interpreted as distal intrusions associated to the Sunsás Orogen. All post-Transplatense metagabbros have geochemical signature of island arc basalt derived from primitive mantle with enrichment of LILE and depletion of HFSE. These characteristics point to the recurrence of magma chambers intermittently active during the Rhyacian, Statherian, Ectasian, and Stenian, all with a similar source. The term "Transplatense" is used to replace "Trans-Amazonian" events

  5. Documentos audiovisuales y prácticas laborales en las Bibliotecas Populares de La Plata: un estudio de caso Audiovisual documents and work practices in Popular Libraries of La Plata: a case study

    Directory of Open Access Journals (Sweden)

    Javier Planas

    2007-12-01

    Full Text Available Se describe y analiza el tratamiento que los documentos audiovisuales reciben, a través de las políticas de desarrollo de colecciones, los procesos técnicos y los servicios, en una muestra de bibliotecas populares de la ciudad de La Plata. Se señala la existencia de un panorama común a la mayor parte de las bibliotecas. Se destacan las características de dos instituciones que se constituyen como excepciones a esta generalidad.The treatment received by audiovisual documents is described and analyzed in relation with the policies of collection development, technical processes and services, in a sample of popular libraries located in La Plata City. The existence of a common picture in the great majority of these libraries is corroborated. The characteristics of two of the libraries are noted as exceptions to the general situation.

  6. Towards the classification of eutrophic condition in estuaries

    CSIR Research Space (South Africa)

    Lemley, DA

    2015-10-01

    Full Text Available Water quality and ecological integrity of estuaries closely reflect activities within the entire upstream catchment. Much emphasis has been placed on the response of estuaries to anthropogenic stressors through the use of monitoring programmes. Key...

  7. Pollution induced tidal variability in water quality of Mahim Estuary

    Digital Repository Service at National Institute of Oceanography (India)

    Zingde, M.D.; Sabnis, M.M.

    Variability of water quality due to release of wastewater in Mahim Estuary (Maharashtra, India) and associated nearshore waters is discussed. The mixing of low salinity contaminated estuary water with high salinity bay water was considerably...

  8. Benthos of Beypore and Korapuzha estuaries of North Kerala

    Digital Repository Service at National Institute of Oceanography (India)

    Devi, K.S.; Sankaranarayanan, V.N.; Venugopal, P.

    The benthos from Beypore and Korapuzha estuaries were studied for one year. Environmental features, sediment characteristics and organic carbon content were estimated. Benthic density was high during monsoon and postmonsoon in both the estuaries...

  9. Variations of dissolved oxygen in Mandovi and Zuari estuaries

    Digital Repository Service at National Institute of Oceanography (India)

    DeSousa, S.N.; SenGupta, R.

    During non-monsoon months the estuaries were well mixed showing uniform oxygen concentrations from surface to bottom. However, during monsoon months both the estuaries showed stratified conditions with surface water showing high oxygen concentration...

  10. Nutrient characterisation of river inflow into the estuaries of the ...

    African Journals Online (AJOL)

    Nutrient characterisation of river inflow into the estuaries of the Gouritz Water ... into the estuaries within the Gouritz Water Management Area (WMA) of South Africa. ... Long-term water quality monitoring data (dissolved inorganic nitrogen, i.e. ...

  11. Skagit IMW - Skagit River Estuary Intensively Monitored Watershed Project

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This study evaluates system-level effects of several estuary restoration projects on juvenile Chinook salmon production in the Skagit River estuary. The monitoring...

  12. Origin and composition of particulate organic matter in a macrotidal turbid estuary: The Gironde Estuary, France

    Science.gov (United States)

    Savoye, Nicolas; David, Valérie; Morisseau, François; Etcheber, Henri; Abril, Gwenaël; Billy, Isabelle; Charlier, Karine; Oggian, Georges; Derriennic, Hervé; Sautour, Benoît

    2012-08-01

    At the interface between continent and ocean, estuaries receive particles, and especially particulate organic matter (POM) originating from these two reservoirs, but also produce POM, through autochthonous primary production. The origin and composition of surface POM in the Gironde Estuary (SW France) and the environmental forcing of its variability was investigated using the data set produced by the French Coastal Monitoring Network SOMLIT (Service d'Observation en Milieu LITtoral; monthly like sampling during years 2007-2009). This estuary is considered as a model of macrotidal turbid estuaries. Using elemental and isotopic composition of the POM, we estimated that, at the inner estuary space scale and inter-annual time scale, surface particulate organic carbon (POC) was composed of terrestrial POM originated from the turbidity maximum (96.4%; refractory POC) and flood events (1.6%; labile and refractory POC), and of riverine (0.1%), estuarine (0.8%) and marine (1.1%) phytoplankton, i.e. that POC was 98% and 2% of terrestrial and phytoplankton origin, respectively. However, there was a clear spatial gradient: the phytoplankton contribution increases from ca. 1% in the upper and middle estuary to 8.5% in the lower estuary, where light condition is more favourable to plankton growth. The low contribution of phytoplankton to the POC is a characteristic of the Gironde estuary and contrast with other large temperate estuaries. Statistical analysis indicates that salinity, river flow and SPM concentration, and thus associated hydro-dynamic and sedimentary processes, were the only environmental forcings to the composition of surface POC in this system, at intra- and inter-annual time scale. In contrast, temperature and nutrient concentrations, and thus associated processes, do not force this composition of POC. By combining POC fluxes entering the inner estuary (literature data), POC loss as dissolved organic carbon and CO2 and as sediment trapping within the inner

  13. The herbicide Glyphosate affects nitrification in the Elbe estuary, Germany

    Science.gov (United States)

    Sanders, Tina; Lassen, Stephan

    2015-04-01

    The Elbe River is one of the biggest European rivers discharging into the North Sea. It also transports high amounts of nutrients and pollutants like pesticides. Important source regions of both nutrients and pollutants are located within the river catchment, which is dominated by agricultural land-use. From these agricultural soils, pesticides can be carried via the river and estuary into the North Sea. Glyphosate (N-(phosphonomethyl) glycine) is the most commonly used herbicide worldwide and mainly used to regulate unwanted plant growth and for the expedition of crop ripening. In Germany, ~ 6000 tons of glyphosate are applied yearly in agriculture and private use. Glyphosate is degradable by microorganisms and has a half-life in water of 35 to 60 days. This herbicide specifically inhibits 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS), an enzyme that catalyzes the biosynthesis of essential aromatic amino acids in plants, fungi, and bacteria. Nitrifying bacteria, which play an important role in the internal nitrogen cycling in the Elbe estuary, also possess this enzyme. The aim of our study was to quantify the concentration of glyphosate in water and sediment samples of the Elbe to get an overview about relevant environmental levels and to assess the impact of glyphosate on inhibition of nitrifying activities. To quantify the effect of glyphosate on nitrification activity, natural samples as well as pure cultures of Nitrosomonas europea (strain Nm50) were incubated with different concentrations of glyphosate over a period of some weeks. The nitrifying activity was determined according to changes of the nitrite and nitrate concentration as well as the cell number. Glyphosate was detectable in water and sediment samples in the Elbe estuary with up to 5 ppb mainly in the Port of Hamburg region. In both incubation experiments an inhibiting effect of glyphosate on nitrification could be shown. The incubated natural water sample was affected by a glyphosate

  14. Major hydrogeochemical processes in an acid mine drainage affected estuary.

    Science.gov (United States)

    Asta, Maria P; Calleja, Maria Ll; Pérez-López, Rafael; Auqué, Luis F

    2015-02-15

    This study provides geochemical data with the aim of identifying and quantifying the main processes occurring in an Acid Mine Drainage (AMD) affected estuary. With that purpose, water samples of the Huelva estuary were collected during a tidal half-cycle and ion-ion plots and geochemical modeling were performed to obtain a general conceptual model. Modeling results indicated that the main processes responsible for the hydrochemical evolution of the waters are: (i) the mixing of acid fluvial water with alkaline ocean water; (ii) precipitation of Fe oxyhydroxysulfates (schwertmannite) and hydroxides (ferrihydrite); (iii) precipitation of Al hydroxysulfates (jurbanite) and hydroxides (amorphous Al(OH)3); (iv) dissolution of calcite; and (v) dissolution of gypsum. All these processes, thermodynamically feasible in the light of their calculated saturation states, were quantified by mass-balance calculations and validated by reaction-path calculations. In addition, sorption processes were deduced by the non-conservative behavior of some elements (e.g., Cu and Zn). Copyright © 2014 Elsevier Ltd. All rights reserved.

  15. Scientific investigation for the integrated environmental administration of shared aquatic spaces, the challenge is to pass from the words to the facts: the case of the Rio de la Plata and its marine front (RPFM)

    International Nuclear Information System (INIS)

    Cantera Kintz, Jaime Ricardo

    2005-01-01

    The environmental management of Tran-boundary water bodies presents several limitations, ranging from the complex geographical and environmental contexts to differences in jurisdiction and governance, and also involving the interdisciplinary topics included in the integrated environmental management. Any program of environmental planning mainly needs of scientific research made in a close coordination and cooperation, since underestimated aspects cause management weakness. This paper describes the contexts in which the Argentinean-Uruguayan Binational Project Environmental Protection of the Rio de la Plata and its Maritime Front (RPFM) is developed, the main tools to build the scientific knowledge, and the strategies followed to implement a cooperative framework with the participation of environmental management and research institutions of both countries in the pursue of Project objectives

  16. Environmental flow assessments for transformed estuaries

    Science.gov (United States)

    Sun, Tao; Zhang, Heyue; Yang, Zhifeng; Yang, Wei

    2015-01-01

    Here, we propose an approach to environmental flow assessment that considers spatial pattern variations in potential habitats affected by river discharges and tidal currents in estuaries. The approach comprises four steps: identifying and simulating the distributions of critical environmental factors for habitats of typical species in an estuary; mapping of suitable habitats based on spatial distributions of the Habitat Suitability Index (HSI) and adopting the habitat aggregation index to understand fragmentation of potential suitable habitats; defining variations in water requirements for a certain species using trade-off analysis for different protection objectives; and recommending environmental flows in the estuary considering the compatibility and conflict of freshwater requirements for different species. This approach was tested using a case study in the Yellow River Estuary. Recommended environmental flows were determined by incorporating the requirements of four types of species into the assessments. Greater variability in freshwater inflows could be incorporated into the recommended environmental flows considering the adaptation of potential suitable habitats with variations in the flow regime. Environmental flow allocations should be conducted in conjunction with land use conflict management in estuaries. Based on the results presented here, the proposed approach offers flexible assessment of environmental flow for aquatic ecosystems that may be subject to future change.

  17. La construccion social del paisaje cultural. Entre el Paseo del Bosque y el Estadio de Estudiantes de la Plata

    Directory of Open Access Journals (Sweden)

    Mabel Irma Contin

    2011-01-01

    Full Text Available Este artículo presenta los resultados de una investigación sobre las transformaciones y tensiones en el espacio público central cuyo propósito ha sido descubrir, finalmente, los valores en juego en la gestión contemporánea del paisaje cultural urbano. Dicha investigación toma como caso de estudio la ciudad de La Plata (Argentina y su principal parque urbano, el Paseo del Bosque. Éste contiene en uno de sus bordes al estadio de fútbol del Club Estudiantes de La Plata, uno de los equipos emblemáticos de la ciudad, cuyo proyecto de renovación ha originado un conflicto urbano de una dificultad sin precedentes.

  18. The Estuary Guide. Level 3: High School. Draft.

    Science.gov (United States)

    Alexander, Glen; And Others

    Estuaries are marine systems that serve as nurseries for animals, links in the migratory pathways, and habitat for a complex community of organisms. This curriculum guide intended for use at the high school level seeks to teach what estuaries are; provide opportunities to practice decision-making that affects estuaries; and encourage students to…

  19. Improving navigability on the Kromme River Estuary: A choice ...

    African Journals Online (AJOL)

    Navigation of estuaries is a vitally important aspect of boating recreation in South Africa and elsewhere. This paper uses a choice experiment to estimate recreation values of the Kromme River Estuary, a popular estuary along South Africa's east coast. This valuation methodology allows for the identification of preferred ...

  20. Seasonal mercury concentrations and δ15N and δ13C values of benthic macroinvertebrates and sediments from a historically polluted estuary in south central Chile

    International Nuclear Information System (INIS)

    Díaz-Jaramillo, Mauricio; Muñoz, Claudia; Rudolph, Ignacio; Servos, Mark; Barra, Ricardo

    2013-01-01

    The Lenga Estuary is one of the most industrialized sites in south central Chile where the historic operation of chlor-alkali plants resulted in large quantities of mercury (Hg) being deposited into the estuary. This historical contamination may still represent a risk to the biota in the estuary. To investigate this four macroinvertebrates, Neotrypaea uncinata (ghostshrimp), Elminius kingii (barnacle), Hemigrapsus crenulatus (shore crab) and Perinereis gualpensis (ragworm) were collected seasonally from three different sites in the Lenga Estuary and one in a reference estuary (Tubul Estuary), and analyzed for Hg and stable isotopes (δ 15 N and δ 13 C). Mercury concentrations in Lenga sediments ranged from 0.4 ± 0.1 to 13 ± 3 mg/kg, while those in Tubul sediments ranged from 0.02 ± 0.01 to 0.07 ± 0.09 mg/kg. Total Hg concentrations of invertebrates were significantly different between estuaries (p 0.05). In contrast, organic Hg concentrations were different by species and season with shore crab muscle tissues exhibiting the greatest percent difference. Site-specific relationships demonstrated that total Hg concentrations in ragworm best reflected the total Hg sediment mercury concentrations. Signatures of δ 13 C were correlated to the organic Hg % rather than total Hg. This suggests that organic Hg concentrations in these species were related to the carbon sources. -- Highlights: ► Hg in sediments and biota from Lenga Estuary were elevated compared to nearby estuary. ► Invertebrates showed interspecific and seasonal differences in terms of organic Hg %. ► Total Hg levels in the ragworm best reflect Hg sediment gradient in Lenga Estuary. ► Interspecific variation in δ 13 C signatures indicated different feeding modes. ► Organic forms of Hg in invertebrates were mainly related to the carbon sources.

  1. Comparison of environmental forcings affecting suspended sediments variability in two macrotidal, highly-turbid estuaries

    Science.gov (United States)

    Jalón-Rojas, Isabel; Schmidt, Sabine; Sottolichio, Aldo

    2017-11-01

    The relative contribution of environmental forcing frequencies on turbidity variability is, for the first time, quantified at seasonal and multiannual time scales in tidal estuarine systems. With a decade of high-frequency, multi-site turbidity monitoring, the two nearby, macrotidal and highly-turbid Gironde and Loire estuaries (west France) are excellent natural laboratories for this purpose. Singular Spectrum Analyses, combined with Lomb-Scargle periodograms and Wavelet Transforms, were applied to the continuous multiannual turbidity time series. Frequencies of the main environmental factors affecting turbidity were identified: hydrological regime (high versus low river discharges), river flow variability, tidal range, tidal cycles, and turbulence. Their relative influences show similar patterns in both estuaries and depend on the estuarine region (lower or upper estuary) and the time scale (multiannual or seasonal). On the multiannual time scale, the relative contribution of tidal frequencies (tidal cycles and range) to turbidity variability decreases up-estuary from 68% to 47%, while the influence of river flow frequencies increases from 3% to 42%. On the seasonal time scale, the relative influence of forcings frequencies remains almost constant in the lower estuary, dominated by tidal frequencies (60% and 30% for tidal cycles and tidal range, respectively); in the upper reaches, it is variable depending on hydrological regime, even if tidal frequencies are responsible for up 50% of turbidity variance. These quantifications show the potential of combined spectral analyses to compare the behavior of suspended sediment in tidal estuaries throughout the world and to evaluate long-term changes in environmental forcings, especially in a context of global change. The relevance of this approach to compare nearby and overseas systems and to support management strategies is discussed (e.g., selection of effective operation frequencies/regions, prediction of the most

  2. Diagnóstico estructural de la cadena de valor del turismo de reuniones en La Plata

    OpenAIRE

    Lauman, María Victoria

    2015-01-01

    En el transcurso de la obra se realiza un estudio y una evaluación sobre el estado actual en que se encuentran cada uno de los componentes de la cadena de valor de la cual depende el turismo de reuniones en la ciudad de La Plata, para tomar conocimiento de la oferta turística de reuniones existente en la ciudad y poder contribuir a su mejora. Facultad de Ciencias Económicas

  3. Why Do Some Estuaries Close: A Model of Estuary Entrance Morphodynamics.

    Science.gov (United States)

    McSweeney, S. L.; Kennedy, D. M.; Rutherfurd, I.

    2014-12-01

    Intermittently Closed/Open Coastal Lakes/Lagoons (ICOLLs) are a form of wave-dominated, microtidal estuary that experience periodic closure in times of low river flow. ICOLL entrance morphodynamics are complex due to the interaction between wave, tidal and fluvial processes. Managers invest substantial funds to artificially open ICOLLs as they flood surrounding property and infrastructure, and have poor water quality. Existing studies examine broad scale processes but do not identify the main drivers of entrance condition. In this research, the changes in entrance geomorphology were surveyed before and after artificial entrance openings in three ICOLLs in Victoria, Australia. Changes in morphology were related to continuous measures of sediment volume, water level, tide and wave energy. A six-stage quantitative phase model of entrance geomorphology and hydrodynamics is presented to illustrate the spatio-temporal variability in ICOLL entrance morphodynamics. Phases include: breakout; channel expansion with rapid outflow; open with tidal exchange; initial berm rebuilding with tidal attenuation; partial berm recovery with rising water levels; closed with perched water levels. Entrance breakout initiates incision of a pilot channel to the ocean, whereby basin water levels then decline and channel expansion as the headcut migrates landwards. Peak outflow velocities of 5 m/s-3 were recorded and channel dimensions increased over 6 hrs to 3.5 m deep and 140 m wide. When tidal, a clear semi-diurnal signal is superimposed upon an otherwise stable water level. Deep-water wave energy was transferred 1.8 km upstream of the rivermouth with bores present in the basin. Berm rebuilding occurred by littoral drift and cross-shore transport once outflow ceased and microscale bedform features, particularly antidunes, contributed to sediment progradation. Phase duration is dependant on how high the estuary was perched above mean sea level, tidal prism extent, and onshore sediment supply

  4. Feeding ecology of three juvenile mojarras (Gerreidae in a tropical estuary of northeastern Brazil

    Directory of Open Access Journals (Sweden)

    Antônio Limeira Felinto de Araújo

    Full Text Available ABSTRACT Distributions and feeding ecology of mojarra species from shallow water of a tropical estuary in Northeastern Brazil were observed aiming to investigate differences in distribution and resource partitioning among juveniles of three species of mojarras. Fishes were collected with a beach seine across four sites along a salinity gradient from January to December of 2011. Highest abundances were recorded during the rainy season in the upper and middle estuary. Microcrustaceans, mainly copepods, were the preferential prey items of all mojarras, irrespective of size or hydrological season, suggesting these areas may be important nursery habitats. Juveniles of mojarra used two important mechanisms for exploitation of resources: (1 spatial segregation along the salinity and temperature gradient, such as abundance of Eucinostomus melanopterus increased from downstream to upstream estuary, while Eugerres brasilianus displayed an opposite pattern; (2 differences related to the volumetric proportion of the main prey items, with indications that E. melanopterus and Diapterus rhombeus fed predominantly on Calanoida and Cyclopoida, while the diet of E. brasilianus was dominated by items of infauna. Such strategies were important for resource partitioning, favouring the coexistence of these three species in the estuary.

  5. Historic Habitat Opportunities and Food-Web Linkages of Juvenile Salmon in the Columbia River Estuary, Annual Report of Research.

    Energy Technology Data Exchange (ETDEWEB)

    Bottom, Daniel L.; Simenstad, Charles A.; Campbell, Lance [Northwest Fisheries Science Center

    2009-05-15

    -fresh reaches of the main-stem river and many tidally-influenced estuary tributaries. Finally, our surveys to date characterize wetland habitats within island complexes distributed in the main channel of the lower estuary. Yet some of the most significant wetland losses have occurred along the estuary's periphery, including shoreline areas and tributary junctions. These habitats may or may not function similarly as the island complexes that we have surveyed to date. In 2007 we initiated a second phase of the BPA estuary study (Phase II) to address specific uncertainties about salmon in tidal-fresh and tributary habitats of the Columbia River estuary. This report summarizes 2007 and 2008 Phase II results and addresses three principal research questions: (1) What was the historic distribution of estuarine and floodplain habitats from Astoria to Bonneville Dam? (2) Do individual patterns of estuarine residency and growth of juvenile Chinook salmon vary among wetland habitat types along the estuarine tidal gradient? (3) Are salmon rearing opportunities and life histories in the restoring wetland landscape of lower Grays River similar to those documented for island complexes of the main-stem estuary? Phase II extended our analysis of historical habitat distribution in the estuary above Rkm 75 to near Bonneville Dam. For this analysis we digitized the original nineteenth-century topographic (T-sheets) and hydrographic (H-sheets) survey maps for the entire estuary. Although all T-sheets (Rkm 0 to Rkm 206) were converted to GIS in 2005 with support for the USACE estuary project, final reconstruction of historical habitats throughout the estuary requires completion of the remaining H-sheet GIS maps above Rkm 75 and their integration with the T-sheets. This report summarizes progress to date on compiling the upper estuary H-sheets above Rkm 75. For the USACE estuary project, we analyzed otoliths from Chinook salmon collected near the estuary mouth in 2003-05 to estimate variability

  6. A continuing 30-year decline in water quality of Jiaojiang Estuary, China

    Directory of Open Access Journals (Sweden)

    Chun-ye Wang

    2015-01-01

    Full Text Available A quantitative description of a long-term series of aquatic environmental factors and their spatial distributions was generated using measured data from the Jiaojiang Estuary from 1982 to 2011. The aquatic environmental factors included suspended matter, salinity, and nutrients. Based on these factors, the aquatic ecosystem health in the Jiaojiang Estuary over the last 30 years was analyzed. The results indicated that the suspended matter concentration in the estuary was mainly affected by the amounts of suspended sediment and solid waste, with the value fluctuating over a long period, and the range of high concentration expanded continually; the salinity was mainly affected by precipitation and surface water resources, showing an overall decreasing trend, and the region with low salinity moved seaward and toward the reclamation areas; and the nutritional status, mainly affected by discharge of industrial wastewater and domestic sewage, was satisfactory in the 1980s and 1990s, but the status became severe in recent years. Reclamation had a great influence on these three factors: high reclamation strength led to a significant increase in the suspended matter concentration and a deterioration of the nutritional status, and the reclamation rate was negatively related with the salinity in the estuary. There was a significant positive correlation between the health status of the aquatic ecosystem and salinity, with a correlation coefficient of 0.93. The correlation coefficient between the health status and nutritional status was −0.71, while the correlation between the suspended matter concentration and health status was not as significant as that of the other two factors. The dynamics of the aquatic environment could be divided into four stages: sustainable health from the 1980s to the 1990s, continued deterioration from 2000 to 2003, improvement from 2004 to 2005, and secondary deterioration from 2006 to 2011. The Jiaojiang Estuary is faced with

  7. CO2 emissions from a temperate drowned river valley estuary adjacent to an emerging megacity (Sydney Harbour)

    Science.gov (United States)

    Tanner, E. L.; Mulhearn, P. J.; Eyre, B. D.

    2017-06-01

    The Sydney Harbour Estuary is a large drowned river valley adjacent to Sydney, a large urban metropolis on track to become a megacity; estimated to reach a population of 10 million by 2100. Monthly underway surveys of surface water pCO2 were undertaken along the main channel and tributaries, from January to December 2013. pCO2 showed substantial spatio-temporal variability in the narrow high residence time upper and mid sections of the estuary, with values reaching a maximum of 5650 μatm in the upper reaches and as low as 173 μatm in the mid estuary section, dominated by respiration and photosynthesis respectively. The large lower estuary displayed less variability in pCO2 with values ranging from 343 to 544 μatm controlled mainly by tidal pumping and temperature. Air-water CO2 emissions reached a maximum of 181 mmol C m-2 d-1 during spring in the eutrophic upper estuary. After a summer high rainfall event nutrient-stimulated biological pumping promoted a large uptake of CO2 transitioning the Sydney Harbour Estuary into a CO2 sink with a maximum uptake of rate of -10.6 mmol C m-2 d-1 in the mid-section of the estuary. Annually the Sydney Harbour Estuary was heterotrophic and a weak source of CO2 with an air-water emission rate of 1.2-5 mmol C m-2 d-1 (0.4-1.8 mol C m-2 y-1) resulting in a total carbon emission of around 930 tonnes per annum. CO2 emissions (weighted m3 s-1 of discharge per km2 of estuary surface area) from Sydney Harbour were an order of magnitude lower than other temperate large tectonic deltas, lagoons and engineered systems of China, India, Taiwan and Europe but were similar to other natural drowned river valley systems in the USA. Discharge per unit area appears to be a good predictor of CO2 emissions from estuaries of a similar climate and geomorphic class.

  8. Estuary wader capacity following severe weather mortality

    International Nuclear Information System (INIS)

    Clark, J.A.; Baillie, S.R.; Clark, N.A.; Langston, R.H.W.

    1993-01-01

    The building of a tidal power barrage across an estuary may lead to substantial changes in its ecology. Many of Britain's estuaries hold internationally important numbers of waders. Careful consideration, therefore, needs to be given to the likely effects of tidal power barrages on wader populations. The opportunity for increased understanding of the mechanisms which govern wader populations was provided by a period of severe winter weather in 1991, which resulted in a substantial mortality of waders in eastern England. Such conditions are known to be stressful to birds and the study objectives were to investigate both the effects of and recovery from severe weather. (author)

  9. Earthquake and human impact on the sedimentology and geochemistry of Ahuriri Estuary, Hawke's Bay

    International Nuclear Information System (INIS)

    Chague-Goff, C.; Nichol, S.L.; Ditchburn, R.G.; Trompetter, W.J.; Sutherland, V.T.

    1998-01-01

    Three cores were collected from the intertidal and salt marsh sediments in Ahuriri Estuary, Hawke's Bay, and analysed by sedimentological, chemical and geochronological techniques. Signatures of various events, of both natural and anthropogenic origin, were identified. Evidence for the 1931 Hawke's Bay earthquake, which resulted in an uplift of one to two metres in the Napier area, is given by a change in grainsize distribution in a core from the southern shore of the Lower Estuary. The change to a high energy environment, similar to the present one in the Lower Estuary, has resulted in deposition of sand over fine silt. The data suggest increased sediment accumulation rates following the uplift event, which might be attributed to increased erosion in the upper catchment. There is no evidence of the earthquake at the two other sites sampled, which is probably due to their more sheltered location in the estuary. Post-European settlement impact is mainly restricted to the Lower Estuary, where increased concentrations of Zn, Cr, Pb and Cu may be due to industrial discharges. Evidence of agricultural runoff is given by an increase in Cu concentrations near the Poraiti Hills. The chemical data (Cl and S) suggest a change in the depositional environment in the Upper Estuary due to increased freshwater influx and/or decrease in seawater influence. Dating by 210 Pb infers that this occurred prior to 1931, but the origin and timing of the event are still to be determined. Sediment accumulation rates have averaged 2.5 mm/yr for the last 45 years in the Lower Estuary and 3.8 mm/yr for the last 70 years or so in the Upper Estuary. The variation probably reflects the difference in depositional environment, from a high energy environment dominated by tidal and wave action to a low energy environment with additional organic and fine sediment input from stream runoff. The various signatures identified are based on known events but may be used for identifying events in other less

  10. Carbon Transformations and Source - Sink Dynamics along a River, Marsh, Estuary, Ocean Continuum

    Science.gov (United States)

    Anderson, I. C.; Crosswell, J.; Czapla, K.; Van Dam, B.

    2017-12-01

    Estuaries, the transition zone between land and the coastal ocean, are highly dynamic systems in which carbon sourced from watersheds, marshes, atmosphere, and ocean may be transformed, sequestered, or exported. The net fate of carbon in estuaries, governed by the interactions of biotic and physical drivers varying on spatial and temporal scales, is currently uncertain because of limited observational data. In this study, conducted in a temperate, microtidal, and shallow North Carolina USA estuary, carbon exchanges via river, tributary, and fringing salt marsh, air-water fluxes, sediment C accumulation, and metabolism were monitored over two-years, with sharply different amounts of rainfall. Air-water CO2 fluxes and metabolic variables were simultaneously measured in channel and shoal by conducting high-resolution surveys at dawn, dusk and the following dawn. Marsh CO2 exchanges, sediment C inputs, and lateral exports of DIC and DOC were also measured. Carbon flows between estuary regions and export to the coastal ocean were calculated by quantifying residual transport of DIC and TOC down-estuary as flows were modified by sources, sinks and internal transformations. Variation in metabolic rates, CO2, TOC and DIC exchanges were large when determined for short time and limited spatial scales. However, when scaled to annual and whole estuarine scales, variation tended to decrease because of counteracting metabolic rates and fluxes between channel and shoal or between seasons. Although overall salt marshes accumulated OC, they were a negligible source of DIC and DOC to the estuary, and net inputs of C to the marsh were mainly derived from sediment OC. These results, as observed in other observational studies of estuaries, show that riverine input, light, temperature and metabolism are major controls on carbon cycling. Comparison of our results with other types of estuaries varying in depth, latitude, and nutrification demonstrates large discrepancies underscoring the

  11. The Dom Feliciano belt and its relations with the craton of the Rio de la Plata and Punta del Este ground-Geology and geochronology

    International Nuclear Information System (INIS)

    Preciozzi, F.; Peel, E.; Sanchez, L.; Basei, M.; Ledesma, J.; Muzio, R.

    2005-01-01

    This research was framed in an interdisciplinary project, whose main objective was to make an approach to the geological, tectonic and geochronological evolution of Dom Feliciano Belt and adjacent land partners, especially the Río de la Plata Craton and Land Punta del Este. As was proposed in the project, special attention to geochronological studies from geological transects lent controlled. This yielded the expected level major step forward, not only with regard to the age of different units, but what makes the establishment of an adequate stratigraphy of them. Similarly, geochemical, petrographic and geochronological studies allowed essentially make geotectonic and geologic correlations with the southern portion of Brazil and the western portion of the land I africanos.lo expand involving more project goals in si.En effect began to manifest as a need to know the evolution of equivalent units both in the southern portion of Brazil and Africa Occidental.Estos fundamentalmnete work with West Africa were made with contributions from CONICYT Project 6009 under Projects Geological Correlation 438, 450 and 478 .this pertimitio exchange ideas with leading scientists worldwide many of whom ended up collaborating with it

  12. Establishing nursery estuary otolith geochemical tags for Sea Bass (Dicentrarchus labrax): Is temporal stability estuary dependent?

    Science.gov (United States)

    Ryan, Diarmuid; Wögerbauer, Ciara; Roche, William

    2016-12-01

    The ability to determine connectivity between juveniles in nursery estuaries and adult populations is an important tool for fisheries management. Otoliths of juvenile fish contain geochemical tags, which reflect the variation in estuarine elemental chemistry, and allow discrimination of their natal and/or nursery estuaries. These tags can be used to investigate connectivity patterns between juveniles and adults. However, inter-annual variability of geochemical tags may limit the accuracy of nursery origin determinations. Otolith elemental composition was used to assign a single cohort of 0-group sea bass Dicentrarchus labrax to their nursery estuary thus establishing an initial baseline for stocks in waters around Ireland. Using a standard LDFA model, high classification accuracies to nursery sites (80-88%) were obtained. Temporal stability of otolith geochemical tags was also investigated to assess if annual sampling is required for connectivity studies. Geochemical tag stability was found to be strongly estuary dependent.

  13. Estuary fish data - Juvenile salmon in migratory corridors of lower Columbia River estuary

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Sampling juvenile salmon and associated fishes in open waters of the lower Columbia River estuary. Field work includes bi-weekly sampling during the spring...

  14. Sedimentation and erosion trends over 50 years in the macrotidal Gironde estuary

    Science.gov (United States)

    Sottolichio, Aldo; Hanquiez, Vincent; Arriagada, Joselyn; Jalon-Rojas, Isabel

    2017-04-01

    Recent studies have emphasized on the drastic morphodynamic evolution of many european urbanized estuaries, which have become more turbid during the XXth century because of human-induced deepening and narrowing. For some systems, the availability of data has allowed detailed analysis of evolution, while for some other estuaries, knowledge remains limited. For the latter, it is difficult to elucidate any effect due to climate change, extreme events or human activities. Among them, the Gironde estuary is a macrotidal funnel-shape system, the largest estuary of Western Europe, and characterized by high levels of turbidity. Despite numerous investigations on sedimentary processes carried out in this estuary in the past, there is poor knowledge on the evolution of its morphology and tides over the XXth century. Recently, an investigation on tidal patterns has started in the Garonne tidal river, where it is known that gravel extraction during the sixties has deeply modified the mean depth of the channel. In the meantime, there is evidence of a long-term shift of the turbidity maximum in this area, mainly due to a reduction of river flow in the last 40 years. However, for the main estuarine portion, which represents 80% of the total surface, morphology evolution and associated physical processes remain under-investigated. In this study the morphological evolution of the Gironde estuary has been documented and investigated for the first time, based on some bathymetric and tidal data collected from the archives of the port of Bordeaux. Six bathymetric maps covering a period of 50 years, from the 1953 to year 2000 were compared, highlighting areas of accretion and erosion. Results show that the zone of maximum volume of deposited sediment has migrated continuously towards the upstream portion of the estuary, which is coherent with the intensification of the low river flow periods and the upstream shift of the turbidity maximum zone to the riverine sections. In the meantime

  15. Environmental drivers of the benthic macroinvertebrates community in a hypersaline estuary (Northeastern Brazil

    Directory of Open Access Journals (Sweden)

    Carlinda Railly Ferreira Medeiros

    Full Text Available Abstract Introduction The estuarine community of benthic macroinvertebrates spatially varies in response to changes in environmental variables in these ecosystems. Understanding this variability helps our understanding the mechanisms structuring these communities. Aim Assess the structural aspects of the benthic macroinvertebrate community in a hypersaline estuary, and to relate to environmental variables that influence the community structure along the estuary. Methods The study was conducted at Tubarão river estuary in May 2015. We sampled two estuarine areas (upper and lower, and in each zone were sampled six points composed of two replicas, one sampled in sandy bottom and the other in muddy bottom. Samples of benthic macroinvertebrates and estuarine environmental variables were collected. Environmental drivers of the benthic macroinvertebrate community were determined by Distance-based Linear Models analysis. The contribution of individual species to the dissimilarity between the areas and substrate types were determined by analysis of the percentage of similarity. Results The composition of benthic macroinvertebrate community differed between the upper and lower areas, although it was similar between the muddy and sandy bottoms. The variation in the benthic community between areas was mainly related to the influence of salinity in the upper area. In the lower area, the variation of the macroinvertebrates was related to salinity, associated with other variables in the sandy (temperature, turbidity and dissolved oxygen and muddy (temperature, total dissolved solids and dissolved oxygen substrates. Taxa which contributed most to the dissimilarity between the upper and lower areas were Nereididae (17.89%, Anomalocardia brasiliana (15% and Cirratulidae (10.43%. Conclusions Salinity was the main driver of the structural aspects of the benthic macroinvertebrate community in the upper area of the estuary, although in the lower area a set of

  16. Seasonal variations in the characteristics of superficial sediments in a macrotidal estuary (the Seine inlet, France)

    Science.gov (United States)

    Lesourd, S.; Lesueur, P.; Brun-Cottan, J. C.; Garnaud, S.; Poupinet, N.

    2003-09-01

    Seasonal variations in the sedimentary regime in the mouth of the Seine river, a macrotidal estuary, are described for a 3-year period. The aim of this study is to characterize and to understand the main governing mechanisms, using data from more than a thousand of superficial sediment grab samples or box cores gathered throughout the study period. Analyses of lithofacies and rheological properties were carried out. The distribution of sediments is governed by seasonal meteorological variations. The surface covered by mud reaches a maximum (40% of the total mouth area) during winter. After the winter, the soft mud deposits are progressively redistributed throughout the whole estuary area and onto the shelf. During the lowest freshwater flow at the end of summer, the fine-grained sediments cover less than 20% of the river mouth area. These seasonal variations mainly depend on the river discharge intensity, but are also linked to wave activity. In the study area, the amount of fine-grained deposits after high river flow periods depends on (1) volume of mud erodable within the estuary, (2) the duration of the flood tidal influx, and (3) the duration preceding the particular annual high river flow. During the last decades, filling of the estuary upstream from Honfleur has led to a downstream shift of the fine-grained sediment deposition area; following this, the present-day mud deposition area is in the open part of the estuary, in the subtidal shallow area. Subsequently, fresh mud deposits undergo intense hydrodynamical and meteorological effects, and are partly reworked by waves and tidal currents effects. In this study, it is shown that the behaviour of suspended matter and of superficial sediments is strongly influenced by short but intense events including high river flows and gales.

  17. SÍNTESIS IN SITU DE NANOPARTÍCULAS DE PLATA SOBRE FIBRAS DE FIQUE

    Directory of Open Access Journals (Sweden)

    Sergio Ovalle

    2014-07-01

    Full Text Available Se realizó la síntesis de un material nanocompuesto mediante la deposiciónin situ de nanopartículas (NPs de plata sobre fibras de Fique. La influencia de parámetros experimentales, como concentración del precursor, concentración del agente reductor y tiempos de inmersión de las fibras en la solución del precursor y del agente reductor, se evaluó en términos de recubrimiento, tamaño y dispersión del nanomaterial sobre la superficie. Los nanocompositos fueron caracterizados mediante espectroscopia de reflectancia difusa UV-Vis (RD, microscopía electrónica (FESEM y difracción de rayos X (DRX. El control de los parámetros experimentales mencionados permitió obtener un material que exhibe recubrimiento uniforme y completo de NPs sobre la superficie y tamaños promedio de NPs de 40 nm. 

  18. Game at the old age, stories of old men from Mar del Plata

    Directory of Open Access Journals (Sweden)

    Débora Paola Di Domizio

    2012-11-01

    Full Text Available This text attempts to problematise the topic of game at the old age. The author used the description of an experiment conducted in the city of Mar del Plata in the context of teacher education and whose participants were senior citizens and students in fourth year of their course of studies in Teacher Education in Physical Education in the province. The theoretical framework is provided by the bibliography studied in a Game Theory Seminar attended by the author in her journey to achieve a postgraduate degree as Master in Body Education and by other studies relevant to gerontology. Furthermore, the data obtained through interviews in the fieldwork described here is the input needed to analyze both conceptualizations about old age and aging and the ideas and preconceptions about game in senior citizens. This data also allows the analysis of the games of yesterday and today and the multiplicity of meanings they acquire at the old age, from the voices of the protagonists of the experience

  19. Less is more: bondades de lo breve en el Río de la Plata

    Directory of Open Access Journals (Sweden)

    Julio Prieto

    2014-06-01

    Full Text Available Las famosas palabras del prólogo de El jardín de senderos que se bifurcan condensan una poética narrativa que no sólo podemos considerar emblemática de uno de los autores seminales del siglo XX –Jorge Luis Borges– sino que también informa una de las líneas de escritura más fructíferas de la literatura del Río de la Plata: aquella que cifra un decoro literario en la eficacia de la brevedad. En esa tradición se cuentan algunas de las obras más significativas de esa literatura, desde la microtextualidad de los prólogos, “resúmenes y comentarios” de Borges, a los relatos breves y viñetas humorísticas de Julio Cortázar, Cristina Peri Rossi, Luisa Valenzuela y Ana María Shua.

  20. Mesoproterozoic evolution of the Rio de la Plata Craton in Uruguay: at the heart of Rodinia?

    DEFF Research Database (Denmark)

    Gaucher, Claudio; Frei, Robert; Chemale, Farid

    2011-01-01

    Mesoproterozoic volcanosedimentary units and tectonic events occurring in the Ri´o de la Plata Craton (RPC) are reviewed. A belt consisting of volcanosedimentary successions exhibiting greenschist-facies metamorphism is exposed in the eastern RPC (Nico Pe´rez Terrane) in Uruguay. The Parque UTE...... and top, and Conophyton-bearing limestones and massive dolostones in the middle. A U–Pb LA-ICP MS zircon age of 1,433 ± 6 Ma is reported here for lapilli-tuffs at the base of the Mina Verdu´n Group (Cerro de las Vi´boras Formation). This age shows that the Mina Verdu´n Group immediately postdates...... the Sarandi´ del Yi´ megashear. We report a U–Pb LA-ICP MS zircon age (upper intercept) of 3,096 ± 45 Ma for metatonalites of the La China Complex (Nico Pe´rez Terrane), which yield a lower intercept age of 1,252 Ma. A proto-Andean, Mesoproterozoic belt is envisaged to account for abundant Mesoproterozoic...

  1. Features at some significant estuaries of India

    Digital Repository Service at National Institute of Oceanography (India)

    Bhattathiri, P.M.A.

    in the second and 162 in the third. Most of the studies on various aspects have been confined to very few of these, and that too, mostly to minor ones. Very little work has been carried out from many of the estuaries of the major rivers. An overview...

  2. Radiological assessment of the Esk Estuary

    International Nuclear Information System (INIS)

    Howorth, J.M.; Barr, H.M.; Toole, J.; Strange, L.P.

    1993-01-01

    An assessment has been carried out of the radiological impact of artificial radionuclides in the Esk estuary in Cumbria, UK. Measurements were made of the distributions of 137 Cs, 239 + 240 Pu, and 241 Am in water, surface bed sediments and core profiles. The highest measured concentrations in surface sediments were 2.8 Bq g -1 of 137 Cs, 3.1 Bq g -1 of 239 + 240 Pu and 4.7 Bq g -1 of 241 Am. These values represent significant decreases from similar measurements made in 1970-1980. The measured behaviour of the actinides in low salinity water at the head of the estuary supports previous observations of actinide remobilisation from the bed. A model has been developed which simulates the long-term behaviour of radioactivity in the estuary. The model incorporates representations of tidal mixing, sediment transport, seasonal and long-term sediment accretion. The model also represents long-term build-up in salt marsh regions. The model gives good agreement with measured distributions of 137 Cs, but tends to underestimate actinide concentrations by factors of 2-3. Dose calculations show the importance of radionuclide uptake through livestock grazing sea-washed pasture alongside the estuary. 137 Cs and 241 Am are identified as the most important radionuclides considered in the assessment. (Author)

  3. Padilla Bay: The Estuary Guide. Level 2.

    Science.gov (United States)

    Friesem, Judy; Lynn, Valerie, Ed.

    Estuaries are marine systems that serve as nurseries for animals, links in the migratory pathways, and habitat for a complex community of organisms. This curriculum guide intended for use at the middle school level is designed for use with the on-site program developed by the Padilla Bay National Esturine Research Reserve (Washington). The guide…

  4. The environmental characteristics of the Ganga estuary

    Digital Repository Service at National Institute of Oceanography (India)

    SenGupta, R.; Murty, C.S.; Bhattathiri, P.M.A.

    This report presents physical, chemical and biological observations in the last 160 km stretch of river Ganga for period of 3 years. In the one-layer estuary the mixing is brought about by the horizontal gradient of the flow field closely associated...

  5. Restoration of the Golden Horn Estuary (Halic).

    Science.gov (United States)

    Coleman, Heather M; Kanat, Gurdal; Aydinol Turkdogan, F Ilter

    2009-12-01

    Restoration of the iconic Golden Horn Estuary in Istanbul, Turkey was a substantial political, logistical, ecological, and social challenge. Forty years of uncontrolled industrial and urban growth resulted in thick layers of anoxic sediment, toxic bacteria, strong hydrogen sulfide odor, and ecologically unlivable conditions. The major components of restoration, spanning two decades, have included (1) demolition and relocation of industries and homes along the shore, (2) creation of wastewater infrastructure, (3) removal of anoxic sludge from the estuary, (4) removal of a floating bridge that impeded circulation, and (5) creation of cultural and social facilities. Although Turkey is not known as an environmental leader in pollution control, the sum of these efforts was largely successful in revitalizing the area through dramatic water quality improvement. Consequently, the estuary is once again inhabitable for aquatic life as well as amenable to local resource users and foreign visitors, and Istanbul has regained a lost sense of cultural identity. This paper focuses on literature review and personal interviews to discuss the causes of degradation, solutions employed to rehabilitate the estuary, and subsequent physicochemical, ecological, and social changes.

  6. Estuaries and Tidal Marshes. Habitat Pac.

    Science.gov (United States)

    Fish and Wildlife Service (Dept. of Interior), Washington, DC.

    This educational packet consists of an overview, three lesson plans, student data sheets, and a poster. The overview examines estuaries and tidal or salt marshes by discussing the plants and animals in these habitats, marsh productivity, benefits and management of the habitats, historical aspects, and development and pollution. A glossary and list…

  7. Geochemical studies in the Godavari Estuary, India

    Digital Repository Service at National Institute of Oceanography (India)

    Somayajulu, B.L.K.; Martin, J.M.; Eisma, D.; Thomas, A.J.; Borole, D.V.; Rao, K.S.

    are reported. The DOC and Fe concentrations are lower compared with those in other estuaries of the world and are below the average value reported for world rivers. Silicon behaves non-conservatively; its depletion which is most likely due to biological...

  8. Flushing characteristics of Mahim river estuary (Bombay)

    Digital Repository Service at National Institute of Oceanography (India)

    Sabnis, M.M; Zingde, M

    to the influence of wastewater. Flushing time of 19 tidal cycles was estimated by applying modified tidal prism method. After a large number of tidal cycles the estuary would retain 9.3x10 super(4) m super(3) of wastewater which was over 15% of the spring high tide...

  9. Influence of estuaries on shelf sediment texture

    Digital Repository Service at National Institute of Oceanography (India)

    Nair, R.R.; Hashimi, N.H.

    on the coast. Offshore from regions where there are a large number of estuaries, the inner shelf sediments are fine grained (average mean size 5.02 phi, 0.03 mm), rich in organic matter ( 2%) and low in calcium carbonate ( 25%). In contrast, in regions...

  10. Carbon dioxide emissions from Indian monsoonal estuaries

    Digital Repository Service at National Institute of Oceanography (India)

    Sarma, V.V.S.S.; Viswanadham, R.; Rao, G.D.; Prasad, V.R.; Kumar, B.S.K.; Naidu, S.A.; Kumar, N.A.; Rao, D.B.; Sridevi, T.; Krishna, M.S.; Reddy, N.P.C.; Sadhuram, Y.; Murty, T.V.R.

    estuaries. The mean pCO sub(2) and particulate organic carbon (POC) showed positive relation with rate of discharge suggesting availability of high quantities of organic matter that led to enhanced microbial decomposition. The annual CO sub(2) fluxes from...

  11. Hydrodynamics of the Bot river estuary revisited

    CSIR Research Space (South Africa)

    Van Niekerk, L

    2005-01-01

    Full Text Available For the past 20 years management of the Bot/Kleinmond estuarine system in the south-western Cape has been based on the premise that, barring intervention, the estuary was naturally evolving into a freshwater coastal lake. This paper presents...

  12. Sedimentation in a river dominated estuary

    CSIR Research Space (South Africa)

    Cooper, JAG

    1993-10-01

    Full Text Available The Mgeni Estuary on the wave dominated cast coast of South Africa occupies a narrow, bedrock confined, alluvial valley and is partially blocked at the coast by an elongate sandy barrier. Fluvial sediment extends to the barrier and marine depositon...

  13. Mouth Bar Formation in Yangtze River Estuary

    NARCIS (Netherlands)

    Wei, C.

    2002-01-01

    The periodic shifting of the bifurcation point of the North Channel and South Channel of the Yangtze river is very important in the estuary. The North Channel is bifurcated from the South Branch by cutting a channel through the submerged sandbanks. Once a bifurcation channel is formed, the

  14. Spatial distribution of trace elements in the surface sediments of a major European estuary (Loire Estuary, France): Source identification and evaluation of anthropogenic contribution

    Science.gov (United States)

    Coynel, Alexandra; Gorse, Laureline; Curti, Cécile; Schafer, Jörg; Grosbois, Cécile; Morelli, Guia; Ducassou, Emmanuelle; Blanc, Gérard; Maillet, Grégoire M.; Mojtahid, Meryem

    2016-12-01

    Assessing the extent of metal contamination in estuarine surface sediments is hampered by the high heterogeneity of sediment characteristics, the spatial variability of trace element sources, sedimentary dynamics and geochemical processes in addition to the need of accurate reference values for deciphering natural to anthropogenic contribution. Based on 285 surface sediment samples from the Loire Estuary, the first high-resolution spatial distributions are presented for grain-size, particulate organic carbon (POC) and the eight metals/metalloids identified as priority contaminants (Cd, Zn, Pb, Cu, As, Cr, Ni, Hg) plus Ag (an urban tracer). Grain-size and/or POC are major factors controlling the spatial distribution of trace element concentrations. The V-normalized trace metal concentrations divided by the V-normalized concentrations in the basin geochemical background showed the highest Enrichment Factors for Ag and Hg (EF; up to 34 and 140, respectively). These results suggest a severe contamination in the Loire Estuary for both elements. Intra-estuarine Ag and Hg anomalies were identified by comparison between respective normalized concentrations in the Loire Estuary surface sediments and those measured in the surface sediments at the outlet of the Loire River System (watershed-derived). Anthropogenic intra-estuarine Ag and Hg stocks in the uppermost centimetre of the sediment compared with rough annual fluvial flux estimates suggest that the overall strong Enrichment Factors for Ag (EFAg) and and Hg (EFHg) in the Loire Estuary sediments are mainly due to watershed-derived inputs, highlighting the need of high temporal hydro-geochemical monitoring to establish reliable incoming fluxes. Significant correlations obtained between EFCd and EFAg, EFCu and POC and EFHg and POC revealed common behavior and/or sources. Comparison of trace element concentrations with ecotoxicological indices (Sediment Quality Guidelines) provides first standardized information on the

  15. 76 FR 8345 - Endangered and Threatened Species; Recovery Plan Module for Columbia River Estuary Salmon and...

    Science.gov (United States)

    2011-02-14

    ... and Threatened Species; Recovery Plan Module for Columbia River Estuary Salmon and Steelhead AGENCY.... ACTION: Notice of availability; recovery plan module for Columbia River estuary salmon and steelhead... Plan Module for Salmon and Steelhead (Estuary Module). The Estuary Module addresses the estuary...

  16. Absorption and fluorescence characteristics of chromophoric dissolved organic matter in the Yangtze Estuary.

    Science.gov (United States)

    Sun, Qiyuan; Wang, Chao; Wang, Peifang; Hou, Jun; Ao, Yanhui

    2014-03-01

    The Yangtze Estuary is heavily influenced by coast-continent geochemical processes and anthropogenic activity; thus, the source and distribution of chromophoric dissolved organic matter (CDOM) in the estuary are strongly impacted by these processes. Here, a series of samples were collected from across the Yangtze Estuary to investigate the source and spatial dynamics of CDOM and its components throughout the system. Three indices (a(355), spectral slope, and fluorescence) were then calculated and interpreted. The results indicated that the distribution of CDOM was dominated by allochthonous input, conservative mixing, and phase transfer. The contribution of biogenic CDOM to total CDOM increased with salinity, and three individual CDOM components were identified upon fluorescence excitation emission matrix spectroscopy and parallel factor analysis of the water samples: C1, corresponding to humic substance-like CDOM, C2, corresponding to tryptophan-like CDOM, and C3, corresponding to tyrosine-like CDOM. C1 primarily originated from a terrestrial source, C2 had widespread origins, none of which played a dominant role, and C3 mainly originated from allochthonous input in the medium salinity area. Unexpectedly, no marine humic-like component was found in the surface water of the Yangtze Estuary, possibly because turbidity decreased the depth of sunlight penetration, limiting production of this component.

  17. Autumn ichthyoplankton assemblage in the Yangtze Estuary shaped by environmental factors.

    Science.gov (United States)

    Zhang, Hui; Xian, Weiwei; Liu, Shude

    2016-01-01

    This study investigated the response of the ichthyoplankton community to environmental changes in the Yangtze Estuary using canonical correspondence analysis. Ichthyoplankton community and environmental data were recorded during the autumns of 1998, 2000, 2002, 2003, 2004, 2007 and 2009. Among the ichthyoplankton, the dominant larval and juvenile families were the Engraulidae, Gobiidae and Salangidae, and the most common eggs were from Trichiurus lepturus. The ichthyoplankton was identified via canonical correspondence analysis to three assemblages: an estuary assemblage dominated by Chaeturichthys stigmatias, a coastal assemblage dominated by Engraulis japonicus and Stolephorus commersonii, and an offshore assemblage dominated by Trichiurus lepturus. Regarding environmental factors in the Yangtze Estuary, suspended matter and surface seawater salinity were the main factors influencing the distributions of the different assemblages, while sediment from the Yangtze River during the rainy season and chlorophyll a were the principle drivers of the annual variances in the distribution of ichthyoplankton assemblages. Our aims in this study were to provide detailed characterizations of the ichthyoplankton assemblage in the autumns of seven years, examine the long-term dynamics of autumn ichthyoplankton assemblages, and evaluate the influence of environmental factors on the spatial distribution and inter-annual variations of ichthyoplankton assemblages associated with the Yangtze Estuary.

  18. Autumn ichthyoplankton assemblage in the Yangtze Estuary shaped by environmental factors

    Directory of Open Access Journals (Sweden)

    Hui Zhang

    2016-04-01

    Full Text Available This study investigated the response of the ichthyoplankton community to environmental changes in the Yangtze Estuary using canonical correspondence analysis. Ichthyoplankton community and environmental data were recorded during the autumns of 1998, 2000, 2002, 2003, 2004, 2007 and 2009. Among the ichthyoplankton, the dominant larval and juvenile families were the Engraulidae, Gobiidae and Salangidae, and the most common eggs were from Trichiurus lepturus. The ichthyoplankton was identified via canonical correspondence analysis to three assemblages: an estuary assemblage dominated by Chaeturichthys stigmatias, a coastal assemblage dominated by Engraulis japonicus and Stolephorus commersonii, and an offshore assemblage dominated by Trichiurus lepturus. Regarding environmental factors in the Yangtze Estuary, suspended matter and surface seawater salinity were the main factors influencing the distributions of the different assemblages, while sediment from the Yangtze River during the rainy season and chlorophyll a were the principle drivers of the annual variances in the distribution of ichthyoplankton assemblages. Our aims in this study were to provide detailed characterizations of the ichthyoplankton assemblage in the autumns of seven years, examine the long-term dynamics of autumn ichthyoplankton assemblages, and evaluate the influence of environmental factors on the spatial distribution and inter-annual variations of ichthyoplankton assemblages associated with the Yangtze Estuary.

  19. Use of a Real-Time Remote Monitoring Network (RTRM to Characterize the Guadalquivir Estuary (Spain

    Directory of Open Access Journals (Sweden)

    Isabel Caballero

    2012-02-01

    Full Text Available The temporal variability of hydrological variables in the Guadalquivir estuary was examined during three years through a real-time remote monitoring network (RTRM. The network was developed with the aim of studying the influence of hydrodynamical and hydrological features within the estuary on the functioning of the pelagic ecosystem. Completing this data-gathering network, monthly cruises were performed in order to measure biogeochemical variables that are indicative of the trophic status of the aquatic environment. The results showed that several sources of physical forcing, such as wind, tide-associated currents and river discharge were responsible for the spatio-temporal patterns of dissolved oxygen, salinity and turbidity in the estuary. The analysis was conducted under tidal and flood regime, which allowed us to identify river discharge as the main forcing agent of the hydrology inside the estuary. In particular, episodes of elevated turbidity detected by the network, together with episodes of low salinity and dissolved oxygen were closely related to the increase in water supply from a dam located upstream. The network installed provided accurate data that can be rapidly used for research or educational applications and by policy-makers or agencies in charge of the management of the coastal area.

  20. Baseline metals pollution profile of tropical estuaries and coastal waters of the Straits of Malacca

    International Nuclear Information System (INIS)

    Looi, Ley Juen; Aris, Ahmad Zaharin; Wan Johari, Wan Lutfi; Yusoff, Fatimah Md.; Hashim, Zailina

    2013-01-01

    Highlights: • Order of metals distribution were as follow: Fe > Al > Se > Cu > As > Zn > Mn > Ni > Ba > Pb > Cd > Cr > Co. • As and Cu levels have exceeded Malaysia Marine Water Quality Criteria and Standard. • Seven principal components of PCA were extracted from estuaries and coastal waters. • Mineral-related parameters are main pollution sources in the waters. -- Abstract: The status report on metal pollution in tropical estuaries and coastal waters is important to understand potential environmental health hazards. Detailed baseline measurements were made on physicochemical parameters (pH, temperature, redox potential, electrical conductivity, salinity, dissolved oxygen, total dissolved solid), major ions (Na, Ca, Mg, K, HCO 3 , Cl, SO 4 and NO 3 ) and metals concentrations ( 27 Al, 75 As, 138 Ba, 9 Be, 111 Cd, 59 Co, 63 Cu, 52 Cr, 57 Fe, 55 Mn, 60 Ni, 208 Pb, 80 Se, 66 Zn) at estuaries and coastal waters along the Straits of Malacca. Principal component analysis (PCA) was employed to reveal potential pollution sources. Seven principal components were extracted with relation to pollution contribution from minerals-related parameters, natural and anthropogenic sources. The output from this study will generate a profound understanding on the metal pollution status and pollution risk of the estuaries and coastal system

  1. Nitrogen biogeochemistry in the oligohaline zone of a New England estuary

    Energy Technology Data Exchange (ETDEWEB)

    Holmes, R.M.; Peterson, B.J.; Deegan, L.A.; Hughes, J.E.; Fry, B.

    2000-02-01

    The authors investigated nitrogen cycling in the oligohaline zone of the Parker River estuary in northeastern Massachusetts. They introduced an isotopic tracer ({sup 15}N-NO{sub 3}{sup {minus}}) for 27 days in August 1996 to help determine how watershed-derived nitrogen moves through the upper estuary. The amount of tracer added was sufficient to enrich nitrate isotopically by {approximately}100% in the vicinity of the addition but did not influence nitrate concentration appreciably. During typical summer low-flow conditions as occurred during the addition period, essentially all riverine nitrate (including the nitrate tracer) was rapidly removed from the water column by the planktonic diatom Actinocyclus normanii. Export of tracer down-estuary was low during the isotope addition period, in part because of low river discharge. Instead, most of the nitrogen originally assimilated by A. normanii was transferred to sediments in the oligohaline zone. Nitrogen demand by phytoplankton during summer exceeded riverine supply by an order of magnitude. The additional nitrogen came mainly from the regeneration of benthic nitrogen, although some may have come from groundwater. The whole-ecosystem isotope tracer approach applied here was a powerful means of investigating the fate of watershed-derived nitrogen in the upper estuary.

  2. Secular bathymetric variations of the North Channel in the Changjiang (Yangtze) Estuary, China, 1880-2013: Causes and effects

    Science.gov (United States)

    Mei, Xuefei; Dai, Zhijun; Wei, Wen; Li, Weihua; Wang, Jie; Sheng, Hao

    2018-02-01

    As the interface between the fluvial upland system and the open coast, global estuaries are facing serious challenges owing to various anthropogenic activities, especially to the Changjiang Estuary. Since the establishment of the Three Gorges Dam (TGD), currently the world's largest hydraulic structure, and certain other local hydraulic engineering structures, the Changjiang Estuary has experienced severe bathymetric variations. It is urgent to analyze the estuarine morphological response to the basin-wide disturbance to enable a better management of estuarine environments. North Channel (NC), the largest anabranched estuary in the Changjiang Estuary, is the focus of this study. Based on the analysis of bathymetric data between 1880 and 2013 and related hydrological data, we developed the first study on the centennial bathymetric variations of the NC. It is found that the bathymetric changes of NC include two main modes, with the first mode representing 64% of the NC variability, which indicates observable deposition in the mouth bar and its outer side area (lower reach); the second mode representing 11% of the NC variability, which further demonstrates channel deepening along the inner side of the mouth bar (upper reach) during 1970-2013. Further, recent erosion observed along the inner side of the mouth bar is caused by riverine sediment decrease, especially in relation to TGD induced sediment trapping since 2003, while the deposition along the lower reach since 2003 can be explained by the landward sediment transport because of flood-tide force strengthen under the joint action of TGD induced seasonal flood discharge decrease and land reclamation induced lower reach narrowing. Generally, the upper and lower NC reach are respectively dominated by fluvial and tidal discharge, however, episodic extreme floods can completely alter the channel morphology by smoothing the entire channel. The results presented herein for the NC enrich our understanding of bathymetric

  3. Empresarialidad y desarrollo local en la región rural periurbana de La Plata Entrepreneurship and local development in the peri-urban rural region of La Plata

    Directory of Open Access Journals (Sweden)

    Rossana Cacivio

    2012-01-01

    Full Text Available This article is focused on analytical thinking of the participants of a entrepreneurial development programme in the peri-urban rural region focus in the city of La Plata. The programme it started with an action of the extension of the Universidad Nacional de la Plata [Olmos Emprende], the development led to the joint and more programs national and provincial. The first objective is to describe the conditions in the entrepreneurship in Latin America and contextualize the experience presented. Afterwards a consideration of the local territorial context that would have facilitated the participation in the program, taking into account two regional areas: On the one hand the periurban rural region in general and on the other hand, a series of local dimensions that, in addition to factors techno-economic state and regulatory frameworks, include social and cultural circumstances. The question that crosses the text, focuses on the location of the entrepreneurship in the territory, focusing on their possibilities of local development. We observed the situations of interface between various regional actors, between groups of citizens, various state agencies and the diverse participation also of private agentsEl artículo se centra en la reflexión analítica de los participantes de un programa de desarrollo emprendedor en la Región Rural Periurbana centrada en el municipio de La Plata. El programa partió de una acción de extensión de la Universidad Nacional de La Plata [Olmos Emprende], cuyo desarrollo derivó en la articulación con programas más abarcativos de orden nacional y provincial. El primer objetivo es describir las condiciones específicas en las que se desarrolla la empresarialidad en América Latina y contextualizar la experiencia presentada. Posteriormente se hace una consideración del contexto territorial local que habría facilitado la participación en el programa teniendo en cuenta dos ámbitos regionales: por un lado la Regi

  4. Historical changes in the Columbia River Estuary

    Science.gov (United States)

    Sherwood, Christopher R.; Jay, David A.; Bradford Harvey, R.; Hamilton, Peter; Simenstad, Charles A.

    Historical changes in the hydrology, sedimentology, and physical oceanography of the Columbia River Estuary have been evaluated with a combination of statistical, cartographic, and numerical-modelling techniques. Comparison of data digitized from US Coast and Geodetic Survey bathymetric surveys conducted in the periods 1867-1875, 1926-1937, and 1949-1958 reveals that large changes in the morphology of the estuary have been caused by navigational improvements (jetties, dredged channels, and pile dikes) and by the diking and filling of much of the wetland area. Lesser changes are attributable to natural shoaling and erosion. There has been roughly a 15% decrease in tidal prism and a net accumulation of about 68 × 10 6m 3 of sediment in the estuary. Large volumes of sediment have been eroded from the entrance region and deposited on the continental shelf and in the balance of the estuary, contributing to formation of new land. The bathymetric data indicate that, ignoring erosion at the entrance, 370 to 485 × 10 6m 3 of sediment has been deposited in the estuary since 1868 at an average rate of about 0.5 cm y -1, roughly 5 times the rate at which sea level has fallen locally since the turn of the century. Riverflow data indicate that the seasonal flow cycle of the Columbia River has been significantly altered by regulation and diversion of water for irrigation. The greatest changes have occurred in the last thirty years. Flow variability over periods greater than a month has been significantly damped and the net discharge has been slightly reduced. These changes in riverflow are too recent to be reflected in the available in the available bathymetric data. Results from a laterally averaged, multiple-channel, two-dimensional numerical flow model (described in HAMILTON, 1990) suggest that the changes in morphology and riverflow have reduced mixing, increased stratification, altered the response to fortnightly (neap-spring) changes in tidal forcing, and decreased the

  5. Síntesis de nanopartículas de plata por ablación láser funcionalizadas con bicapa de grafeno

    OpenAIRE

    Damián Briones, María Angelica; Damián Briones, María Angelica; Damián Briones, María Angelica

    2015-01-01

    En este trabajo se obtuvo nanopartículas de plata por ablación laser para luego ser funcionalizadas con bicapa de grafeno, mediante la técnica de evaporación. Para la obtención de las nanopartículas de plata se usó un “target” de plata al 99,9% de pureza el cual fue colocado dentro de un recipiente que contenía agua ultrapura, sobre él se incidió un láser de Nd:AYG modelo Brillant, en el cual se pudo controlar la fluencia, longitud de onda, el medio y el tiempo de ablación. Para la obte...

  6. Multi-proxy evidence of long-term changes in ecosystem structure in a Danish marine estuary, linked to increased nutrient loading

    DEFF Research Database (Denmark)

    Ellegaard, Marianne; Clarke, A.L.; Reuss, Nina Steenberg

    2006-01-01

    This paper presents a study of changes in eutrophication over the past 100 years in a fertile estuary. The Danish estuary Mariager Fjord is a long, narrow sill-fjord with a permanently anoxic basin. In 1997 anoxia spread from the basin to the entire inner estuary, killing almost all eukaryotes...... and prompting debate on the causes. This paper reports a multi-proxy survey of 210Pb-dated sediment cores from the anoxic basin. Analyses of diatoms, dinoflagellates, pigments and geochemical proxies were used to determine changes in ecosystem structure over the past 100 years. The aim was to establish ‘base...... and natural isotopes (d13C, d15N) suggested increasing production and nutrient loading. The main changes in the biological proxies occurred between 1915 and the 1940s, and indicated that the estuary has been somewhat eutrophic since 1900, but that the eutrophication process increased over the past 100 years...

  7. Riesgo de establecimiento del gasterópodo dulceacuícola invasor Melanoides tuberculatus (Thiaridae en el Río de la Plata (Argentina-Uruguay Colonization risks of the invading freshwater gastropod Melanoides tuberculatus (Thiaridae in Río de la Plata (Argentina-Uruguay

    Directory of Open Access Journals (Sweden)

    Diego E. Gutiérrez-Gregoric

    2010-08-01

    Full Text Available Melanoides tuberculatus es un gasterópodo cosmopolita que ha invadido y se ha establecido en casi todos los países del continente americano, desconociéndose en la mayoría de los casos el origen de su introducción. En este trabajo se menciona el riesgo de establecimiento de esta especie en áreas de influencia del Río de la Plata como consecuencia de su registro en acuarios de la ciudad de La Plata (Buenos Aires, Argentina dedicados a la venta de flora y fauna limnética. A principios de 2009, la especie fue identificada a partir de 26 ejemplares procedentes de un comercio, siendo éste el registro más austral de la especie para una localidad de la cuenca del Plata. Revisiones posteriores en 3 locales comerciales de la ciudad confirmaron la presencia de la especie en 2 de ellos. Dicha presencia se relacionó con la adquisición de plantas ornamentales por parte de los establecimientos. La identificación del gasterópodo en la ciudad de La Plata debe considerarse cuidadosamente, debido a las posibles consecuencias que tendría la liberación accidental de este molusco en el Río de la Plata en lo relacionado con el desplazamiento de fauna local y salud pública.Melanoides tuberculatus is a cosmopolitan gastropod that has invaded and has now spread into most countries of the American continent. Introduction pathways remain unknown in most cases. This work draws attention on the colonization risks of this species in the Río de la Plata area as a consequence of its record in flower and pet shops - in the city of La Plata (Buenos Aires, Argentina - in which limnic species are sold. The species was identified at the beginning of 2009 within a lot of 29 specimens from a shop, and this is the southernmost record of this species in the Plata Basin. Subsequent surveys in 3 commercial shops in the same city revealed its presence in 2 of them. This was related to the purchase of ornamental plants by the shops. Identification of this species in the

  8. Dynamics of circulation and salt balance in the upper reaches of Periyar river estuary

    Digital Repository Service at National Institute of Oceanography (India)

    Varma, P.U.; Pylee, A.; Sankaranarayanan, V.N.

    The Eulerian residual currents of the upper reaches of Periyar estuary (Kerala, India) were directed down the estuary throughout the water column during the monsoon season. During the summer months the residual flow was directed up the estuary...

  9. Plankton composition in two estuaries of the Konkan coast during premonsoon season

    Digital Repository Service at National Institute of Oceanography (India)

    Achuthankutty, C.T.; Nair, S.R.S.; Devassy, V.P.; Nair, V.R.

    abundant at the mouth region. Zooplankton biomass was relatively high in the Kajvi Estuary and all the major groups occurred in high density throughout this estuary. In the Shastri Estuary, the zooplankton biomass was relatively lower and all the major...

  10. Using a dual isotopic approach to trace sources and mixing of sulphate in Changjiang Estuary, China

    International Nuclear Information System (INIS)

    Li Siliang; Liu Congqiang; Patra, Sivaji; Wang Fushun; Wang Baoli; Yue Fujun

    2011-01-01

    Highlights: → Changjiang Estuary plays an important role in transportation of the water and solute. → The dual isotopic method could be used to understand sulfate biogeochemistry in estuaries. → Mixing processes should be a major factor involved in the distribution of water and sulphate. → Sulphate in the Changjiang River mainly derived from atmospheric deposition, evaporite dissolution and sulphide oxidation. - Abstract: The dual isotopic compositions of dissolved SO 4 2- in aquatic systems are commonly used to ascertain SO 4 2- sources and possible biogeochemical processes. In this study, the physical parameters, major anions and isotopic compositions of SO 4 2- in water samples from Changjiang River (Nanjin) to the East Sea in Changjiang Estuary were determined. The salinity ranged from 0 per mille to 32.3 per mille in the estuary water samples. The Cl - ,SO 4 2- concentrations and δ 18 O-H 2 O values followed the salinity variations from freshwater to seawater, which indicated that mixing processes might be a major factor involved in the distribution of water and solutes. The contents and isotopic compositions of SO 4 2- suggested that atmospheric deposition, evaporite dissolution and sulphide oxidation were the major sources of dissolved SO 4 2- in the freshwater of Changjiang River. In addition, the mixing model calculated by contents and isotopic compositions of SO 4 2- indicated that the mixing of freshwater and sea water was the major factor involved in SO 4 2- distribution in Changjiang Estuary. However, slightly elevated δ 18 O-SO 4 values were observed in the turbidity maximum zone, which suggested that biological processes might affect the O isotopic compositions of SO 4 2- there.

  11. Source identification, geochemical normalization and influence factors of heavy metals in Yangtze River Estuary sediment.

    Science.gov (United States)

    Sun, Xueshi; Fan, Dejiang; Liu, Ming; Tian, Yuan; Pang, Yue; Liao, Huijie

    2018-06-18

    Sediment samples, including 40 surface samples and 12 sediment cores, were collected from 52 stations of the Yangtze River Estuary (YRE) in 2015 and 2016. The 95% linear prediction intervals (LPI) and principal components analysis (PCA), were conducted to evaluate the metal sources and grain-size effect (GSE). The in situ physico-chemical properties of pH, Eh, DO, salinity, temperature and turbidity were combined to elucidate the relationships between environmental factors and the fate of heavy metals in the river-estuary-shelf system. This study indicates a decreasing trend of metals in sediments from the estuary towards the adjacent shelf and the river channel and that Zn, Cu and Cr are mainly derived from natural processes throughout the catchment, whereas Pb appears to have anthropogenic inputs via atmospheric deposition. Furthermore, considering the best fit regression lines between the concentrations of Al and heavy metals as well as the deficiencies of the conventional C elements /C Al method, we introduce an approach (Al-SN: Al-scope normalization) that can eliminate the GSE on heavy metals and be applied to other estuaries. After Al-scope normalization, the relatively constant levels of Zn, Cu and Cr that remain in sediments from the river channel to the estuary and shelf confirmed that the variation of grain size in sediments almost entirely explained the distribution patterns of sediment toxicity in the YRE, while the enrichment of Pb in estuarine sediments could be attributed to its chemical species and physico-chemical properties. The results further suggest that the relationship between grain size and spatial behavior of sediment pollutants should be given priority over the contamination assessment and provenance discrimination in estuarine or similar environments with complex sediment compositions. Copyright © 2018 Elsevier Ltd. All rights reserved.

  12. The effects of wastewater discharges on the functioning of a small temporarily open/closed estuary

    Science.gov (United States)

    Lawrie, Robynne A.; Stretch, Derek D.; Perissinotto, Renzo

    2010-04-01

    Wastewater discharges affect the functioning of small temporarily open/closed estuaries (TOCEs) through two main mechanisms: (1) they can significantly change the water balance by altering the quantity of water inflows, and (2) they can significantly change the nutrient balance and hence the water quality. This study investigated the bio-physical responses of a typical, small TOCE on the east coast of South Africa, the Mhlanga Estuary. This estuary receives significant inflows of treated effluent from upstream wastewater treatment works. Water and nutrient budgets were used together with biological sampling to investigate changes in the functioning of the system. The increase in inflows due to the effluent discharges has significantly increased the mouth breaching frequency. Furthermore, when the mouth closes, the accumulation of nutrients leads to eutrophication and algal blooms. A grey water index, namely the proportion of effluent in the estuary and an indicator of the additional nutrient inputs into the estuary, reached high values (≳50%) during low flow regimes and when the mouth was closed. In these hyper-eutrophic conditions (DIN and DIP concentrations up to 457 μM and 100 μM respectively), field measurements showed that algal blooms occurred within about 14 days following closure of the mouth (chlorophyll-a concentrations up to 375 mg chl-a m -3). Water and nutrient balance simulations for alternative scenarios suggest that further increases in wastewater discharges would result in more frequent breaching events and longer open mouth conditions, but the occurrence of hyper-eutrophic conditions would initially intensify despite more frequent openings. The study indicates how water and nutrient balance simulations can be used in the planning and impact assessment of wastewater treatment facilities.

  13. Alkaline Phosphatase Activity : an overlooked player on the phosphate behavior in macrotidal estuaries

    Science.gov (United States)

    Delmas, Daniel; Labry, Claire; Youenou, Agnes; Quere, Julien; Auguet, Jean Christophe; Montanie, Helene

    2014-05-01

    The non-conservative behavior of phosphate within the estuarine salinity gradient is essentially assigned to physico-chemical processes, such as desorption at low salinity and to benthic exchanges. Microbial phosphatase activity (APA), generally related to phosphate deficiency, is seldom studied in phosphate rich estuarine waters. In order to address the impact of microbial activity (bacterial abundance, production BSP, APA) on phosphate behavior, we studied these activities on a seasonal basis within the salinity gradient of two macrotidal estuaries presenting different levels of suspended solids. Whatever the season the Charente estuary is characterized by high levels of Suspended Particulate Matter (SPM > 1g.L-1), particularly in the Maximum Turbidity Zone (MTZ) located at the 5-10 psu. In this area characterized by high BSP and APA there is a significant increase of PO4 levels especially during summer. In the Aulne estuary the particle load is significantly lower (1/10) but high BSP and APA are equally recorded. In the highly turbid waters of the Charente estuary, active phytoplankton is virtually absent as pheopigments constitute up to 80% of the total pigments, particularly in the MTZ, therefore APA may essentially have a bacterial origin. In the Aulne estuary attached bacteria are dominant, both in numbers and production, and their distribution along the haline gradient perfectly follows those of APA and phosphate levels. These observations, associated with the very close relationships observed between APA, SPM and BSP, suggest that APA derive mainly from bacterial (attached) origin and operate at the expense of particulate phosphorus and hence contribute to PO4 regeneration, especially in spring and summer. Finally, as APA increased as PO4, whereas the reverse is observed in both fresh and marine waters, an original scheme for APA regulation, related to the large dominance of attached bacteria can be described for the estuarine waters.

  14. Carbonate system and nutrients in the Pearl River estuary, China: Seasonal and inter-annual variations

    Science.gov (United States)

    Guo, X.

    2017-12-01

    Located in southern China and surrounded by several metropolis, the Pearl River estuary is a large subtropical estuary under significant human perturbation. We examined the impact of sewage treatment rate on the water environmental factors. Carbonate system parameters (Dissolved inorganic carbon or DIC, Total alkalinity or TA, and pH), and nutrients were surveyed in the Pearl River estuary from 2000 to 2015. Spatially, concentrations of nutrients were high at low salinity and decreased with salinity in both wet and dry seasons although seasonal variation occurred. However, distribution patterns of DIC and TA differed in wet and dry seasons. In wet season, both DIC and TA were low at low salinity (600-1500 umol kg-1) and increased with salinity, but in dry season they were high at low salinity (3000-3500 umol kg-1) and decreased with salinity. Compared with the years before 2010, both values and distribution patterns of DIC, TA and pH were similar among the years in wet season, but they were conspicuously different in the upper estuary in dry season. Both DIC and TA were more than 1000 umol kg-1 lower than those in the years before 2010. For nutrients at low salinity, the ammonia concentration was much lower in the years after 2010 (200 vs. 400 umol kg-1 in wet season and 400 vs. 800 umol kg-1 in dry season), but nitrate concentration was slightly higher (180 vs 120 mmol kg-1 in wet season and 200 vs 180 mmol kg-1 in dry season). As a reference, carbonate system parameters and nutrients were stable among the 16 years in the adjacent northern South China Sea. The variations in biogeochemical processes induced by nutrients concentration and structure as a result of sewage discharge will be discussed in detail. The decrease in DIC, TA and nutrients in the upper Pearl River estuary after 2010 was due mainly to the improvement of sewage treatment rate and capacity.

  15. Trace elements and radionuclides in the Connecticut River and Amazon River estuary

    International Nuclear Information System (INIS)

    Dion, E.P.

    1983-01-01

    The Connecticut River, its estuary and the Amazon River plume were studied to elucidate processes which control the flux of nuclides to the sea. Major ions (Ca, Mg, Na, Cl, Bicarbonate) and selected trace elements (Ra, Ba, Cu, Si) are introduced to the Connecticut River in proportion to the total dissolved load of various groundwaters. Si, Ra, and Ba are subject to removal from solution by seasonal diatom productivity; whereas the other groundwater-derived elements are found in proportion to TDS both time and space. These nuclides are released in the estuary when a portion of the Ra, Ba, and Si in riverine biogenic detritus is trapped in salt marshes and coves bordering the estuary where it redissolves and is exported to the main river channel at ebb tide. In the Amazon River estuary, the Ra and Ba are released in mid-salinity waters. Ra and Ba together with Si are subsequently removed by diatom productivity as reflected in increased Ra and Ba in the suspended particles and depleted dissolved nuclide concentrations in samples from the high productivity zone. In both the Connecticut River system and the Amazon River plume, Cu behaves conservatively; whereas the fates of Fe and Al are linked to soil-derived humic acids. Trace elements in Amazon plume sediments are found simply in proportion to the percentage of fine-grained size materials, despite low Th-228/Ra-228 mean residence times in the plume and the presence of Cs-137 in the sediment column. Estimates of the total flux of nuclides to the oceans can best be calculated on a mass balance basis using groundwater inputs. Unless significant repositories for nuclides exist in the river-estuarine system, the groundwater flux of dissolved nuclides is net flux to the ocean despite the reactions which occur in both rivers and estuaries

  16. Multiscale patterns in the diversity and organization of benthic intertidal fauna among French Atlantic estuaries

    Science.gov (United States)

    Blanchet, Hugues; Gouillieux, Benoît; Alizier, Sandrine; Amouroux, Jean-Michel; Bachelet, Guy; Barillé, Anne-Laure; Dauvin, Jean-Claude; de Montaudouin, Xavier; Derolez, Valérie; Desroy, Nicolas; Grall, Jacques; Grémare, Antoine; Hacquebart, Pascal; Jourde, Jérôme; Labrune, Céline; Lavesque, Nicolas; Meirland, Alain; Nebout, Thiebaut; Olivier, Frédéric; Pelaprat, Corine; Ruellet, Thierry; Sauriau, Pierre-Guy; Thorin, Sébastien

    2014-07-01

    Based on a parallel sampling conducted during autumn 2008, a comparative study of the intertidal benthic macrofauna among 10 estuarine systems located along the Channel and Atlantic coasts of France was performed in order to assess the level of fauna similarity among these sites and to identify possible environmental factors involved in the observed pattern at both large (among sites) and smaller (benthic assemblages) scales. More precisely this study focused on unraveling the observed pattern of intertidal benthic fauna composition and diversity observed at among-site scale by exploring both biotic and abiotic factors acting at the among- and within-site scales. Results showed a limited level of similarity at the among-site level in terms of intertidal benthic fauna composition and diversity. The observed pattern did not fit with existing transitional water classification methods based on fish or benthic assemblages developed in the frame of the European Water Framework Directive (WFD). More particularly, the coastal plain estuaries displayed higher among-site similarity compared to ria systems. These coastal plain estuaries were characterized by higher influence of river discharge, lower communication with the ocean and high suspended particulate matter levels. On the other hand, the ria-type systems were more dissimilar and different from the coastal plain estuaries. The level of similarity among estuaries was mainly linked to the relative extent of the intertidal "Scrobicularia plana-Cerastoderma edule" and "Tellina tenuis" or "Venus" communities as a possible consequence of salinity regime, suspended matter concentrations and fine particles supply with consequences on the trophic functioning, structure and organization of benthic fauna. Despite biogeographical patterns, the results also suggest that, in the context of the WFD, these estuaries should only be compared on the basis of the most common intertidal habitat occurring throughout all estuarine systems

  17. Multi-sensor analysis to study turbidity patterns in the Guadalquivir estuary

    OpenAIRE

    I. Caballero; G. Navarro

    2016-01-01

    Revista oficial de la Asociación Española de Teledetección [EN] A detailed study of the mechanisms generated through the turbidity plume and its variability at the Guadalquivir estuary has been carried out with remote sensing and in situ data. Several sensors with different characteristics have been required (spatial, temporal and spectral resolution), thereby providing information for a multi-sensor analysis. The main objective was to determine the water quality parameters (suspended soli...

  18. Benthic fluxes in a tropical estuary and their role in the ecosystem

    Digital Repository Service at National Institute of Oceanography (India)

    Pratihary, A.K.; Naqvi, S.W.A.; Naik, H.; Thorat, B.R.; Narvenkar, G.; Manjunatha, B.R.; Rao, V.P.

    in the Estuary. Based on these observations we hypothesize that it is mainly benthic NH 4 + efflux that sustains high estuarine productivity in the NO 3 - depleted dry season. Keywords: Nutrients; Primary production; Denitrification; Bioturbation; Benthic..., nearshore and continental shelves occupy just about 10 % of the global oceanic area, between 30-50 % of the marine primary production occurs in these regions (Romankevich, 1984; Walsh, 1991) which also sustains about 90 % of the fisheries resource. Coastal...

  19. Radioactive Cs in the estuary sediments near Fukushima Daiichi Nuclear Power Plant

    Energy Technology Data Exchange (ETDEWEB)

    Yamasaki, Shinya, E-mail: s-yamasaki@ied.tsukuba.ac.jp [Faculty of Pure and Applied Sciences and Center for Research in Isotopes and Environmental Dynamics, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8577 (Japan); Imoto, Junpei; Furuki, Genki; Ochiai, Asumi [Department of Chemistry, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka 812-8581 (Japan); Ohnuki, Toshihiko [Advanced Science Research Center, Japan Atomic Energy Agency, Shirakata Shirane 2-4, Tokai, Ibaraki 319-1195 (Japan); Sueki, Keisuke [Faculty of Pure and Applied Sciences and Center for Research in Isotopes and Environmental Dynamics, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8577 (Japan); Nanba, Kenji [Department of Environmental Management, Faculty of Symbiotic System Science, Fukushima University, Kanayagawa 1, Fukushima, 960-1296 (Japan); Ewing, Rodney C. [Department of Geological Sciences and Center for International Security and Cooperation, Stanford University, Stanford, CA 94305-2115 (United States); Utsunomiya, Satoshi [Department of Chemistry, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka 812-8581 (Japan)

    2016-05-01

    The migration and dispersion of radioactive Cs (mainly {sup 134}Cs and {sup 137}Cs) are of critical concern in the area surrounding the Fukushima Daiichi Nuclear Power Plant (FDNPP). Considerable uncertainty remains in understanding the properties and dynamics of radioactive Cs transport by surface water, particularly during rainfall-induced flood events to the ocean. Physical and chemical properties of unique estuary sediments, collected from the Kuma River, 4.0 km south of the FDNPP, were quantified in this study. These were deposited after storm events and now occur as dried platy sediments on beach sand. The platy sediments exhibit median particle sizes ranging from 28 to 32 μm. There is increasing radioactivity towards the bottom of the layers deposited; approximately 28 and 38 Bq g{sup −1} in the upper and lower layers, respectively. The difference in the radioactivity is attributed to a larger number of particles associated with radioactive Cs in the lower part of the section, suggesting that radioactive Cs in the suspended soils transported by surface water has decreased over time. Sequential chemical extractions showed that ~ 90% of {sup 137}Cs was strongly bound to the residual fraction in the estuary samples, whereas 60 ~ 80% of {sup 137}Cs was bound to clays in the six paddy soils. This high concentration in the residual fraction facilitates ease of transport of clay and silt size particles through the river system. Estuary sediments consist of particles < 100 μm. Radioactive Cs desorption experiments using the estuary samples in artificial seawater revealed that 3.4 ± 0.6% of {sup 137}Cs was desorbed within 8 h. More than 96% of {sup 137}Cs remained strongly bound to clays. Hence, particle size is a key factor that determines the travel time and distance during the dispersion of {sup 137}Cs in the ocean. - Highlights: • Cs-137 of estuary sediment impacted by the FDNPP was measured. • Physical and chemical properties were measured also.

  20. Radioactive Cs in the estuary sediments near Fukushima Daiichi Nuclear Power Plant

    International Nuclear Information System (INIS)

    Yamasaki, Shinya; Imoto, Junpei; Furuki, Genki; Ochiai, Asumi; Ohnuki, Toshihiko; Sueki, Keisuke; Nanba, Kenji; Ewing, Rodney C.; Utsunomiya, Satoshi

    2016-01-01

    The migration and dispersion of radioactive Cs (mainly "1"3"4Cs and "1"3"7Cs) are of critical concern in the area surrounding the Fukushima Daiichi Nuclear Power Plant (FDNPP). Considerable uncertainty remains in understanding the properties and dynamics of radioactive Cs transport by surface water, particularly during rainfall-induced flood events to the ocean. Physical and chemical properties of unique estuary sediments, collected from the Kuma River, 4.0 km south of the FDNPP, were quantified in this study. These were deposited after storm events and now occur as dried platy sediments on beach sand. The platy sediments exhibit median particle sizes ranging from 28 to 32 μm. There is increasing radioactivity towards the bottom of the layers deposited; approximately 28 and 38 Bq g"−"1 in the upper and lower layers, respectively. The difference in the radioactivity is attributed to a larger number of particles associated with radioactive Cs in the lower part of the section, suggesting that radioactive Cs in the suspended soils transported by surface water has decreased over time. Sequential chemical extractions showed that ~ 90% of "1"3"7Cs was strongly bound to the residual fraction in the estuary samples, whereas 60 ~ 80% of "1"3"7Cs was bound to clays in the six paddy soils. This high concentration in the residual fraction facilitates ease of transport of clay and silt size particles through the river system. Estuary sediments consist of particles < 100 μm. Radioactive Cs desorption experiments using the estuary samples in artificial seawater revealed that 3.4 ± 0.6% of "1"3"7Cs was desorbed within 8 h. More than 96% of "1"3"7Cs remained strongly bound to clays. Hence, particle size is a key factor that determines the travel time and distance during the dispersion of "1"3"7Cs in the ocean. - Highlights: • Cs-137 of estuary sediment impacted by the FDNPP was measured. • Physical and chemical properties were measured also. • Increasing radioactivity was

  1. [Optical characteristics of colored dissolved organic material (CDOM) in Yangtze Estuary].

    Science.gov (United States)

    Zhu, Wei-Jian; Shen, Fang; Hong, Guan-Lin

    2010-10-01

    Absorption property of colored dissolved organic material (CDOM) is one of the most important contents to remote sensing of ocean color in estuarine and coastal areas. In this study, the optical properties and mixing behavior of CDOM in surface water of Yangtze Estuary were discussed according to the two surveys in August of 2008 and May of 2009. Based on the research, the absorption coefficient and spectral slope were discussed. It was found that in summer of 2008 CDOM absorption coefficients at 440 nm [a(g) (440)], ranged from 0.20 m(-1) to 0.73 m(-1), while the coefficients in 2009 varied between 0.20 m(-1) and 0.77 m(-1). Statistics showed that the power function model fitted the best in the regression analysis of CDOM absorption spectral. The spectral slopes (S(g2)) of CDOM calculated by the power function model ranged from 5.10 to 7.90 in Summer of 2008 and from 2.95 to 6.11 in Spring of 2009. The highest absorption coefficients of two cruises appeared both in the south passage of the Yangtze Estuary. The absorption coefficient in surfer water was observed varied tremendously in the estuary and the offshore area. And the main reason is affected by the turbidity maximum zone. It is observed that the absorption coefficients of CDOM tended to a homogeneous distribution whilst the layers of water mixed tempestuously, but otherwise it always showed a conservative mixing behavior. Because of the frequent mixture, there is not assured correlativity between S(g2) and a(g) (440). In the offshore area of Yangtze Estuary, the effecting of local production cannot be negligent, which differed from the estuary area. Yet when the hydrological environment was relatively stable, the negative relationship between them was very clear. In conclusion, the optical properties and mixing behavior of CDOM had showed tremendous different characteristics from inside the estuary to outside the estuary because of the influence of complex physical, chemical and hydrology conditions.

  2. Short-term tidal asymmetry inversion in a macrotidal estuary (Beira, Mozambique)

    Science.gov (United States)

    Nzualo, Teodósio N. M.; Gallo, Marcos N.; Vinzon, Susana B.

    2018-05-01

    The distortion of the tide in estuaries, bays and coastal areas is the result of the generation of overtides due to the non-linear effects associated with friction, advection, and the finite effects of the tidal amplitude in shallow waters. The Beira estuary is classified as macrotidal, with a large ratio of S2/M2. Typical tides ranges from 6 m and 0.8 m, during springs and neaps tides, respectively. As a consequence of this large fortnightly tidal amplitude difference and the estuarine morphology, asymmetry inversions occur. Two types of tidal asymmetries were investigated in this paper, one considering tidal duration asymmetry (time difference between rising and falling tide) and the other, related to tidal velocity asymmetry (unequal magnitudes of flood and ebb peaks currents). In the Beira estuary when we examine the tidal duration asymmetry, flood dominance is observed during spring tide periods (negative time difference between rising and falling tide), while ebb dominance appears during neap tides (positive time difference between rising and falling tide). A 2DH hydrodynamic model was implemented to analyze this asymmetry inversion. The model was calibrated with water-level data measured at the Port of Beira and current data measured along the estuary. The model was run for different scenarios considering tidal constituents at the ocean boundary, river discharge and the morphology of the estuary. River discharge did not show significant effects on the tidal duration asymmetry. Through comparison of the scenarios, it was shown that the incoming ocean tide at the boundary has an ebb-dominant asymmetry, changing to flood-dominant only during spring tides due to the effect of shoaling and friction within the estuary. During neap tides, the propagation occurs mainly in the channels, and ebb dominance remains. The interplay between the estuary morphodynamics was thus identified and the relation between tidal duration asymmetry and tidal velocity asymmetry was

  3. A new analytical framework for assessing the effect of sea-level rise and dredging on tidal damping in estuaries

    NARCIS (Netherlands)

    Cai, H.; Savenije, H.H.G.; Toffolon, M.

    2012-01-01

    This paper explores different analytical solutions of the tidal hydraulic equations in convergent estuaries. Linear and quasi-nonlinear models are compared for given geometry, friction, and tidal amplitude at the seaward boundary, proposing a common theoretical framework and showing that the main

  4. In Memoriam, En Homenaje a los Drs. Rafael Barberi Zamorano y Ernesto Plata Rueda

    Directory of Open Access Journals (Sweden)

    Eduardo Alvarez P.

    1992-09-01

    Full Text Available

    Y se marcharon…. Partieron como si existiera un acuerdo previo para realizar el encuentro definitivo en la eternidad. Después de una ejemplar y fructífera existencia, plena de múltiples realizaciones, se hace indispensable el goce de la paz eterna. Partieron, pese nos dejaron la huella de dos vidas que marcharon paralelamente con destino hacia un mismo objetivo, el niño colombiano.

    Este ser, la razón primera de nuestra especialidad, incapaz de mentir, inocente, indiferente ante lo bueno y lo malo, indefenso, amante del mundo que lo rodea, tierno y cariñoso. Fueron dos ilustres colombianos que caminaron por el mismo sendero, con diferente fin. Ernesto Plata Rueda en el campo de la investigación y la docencia y Rafael Barberi Zamorano en la dirección y administración del Hospital de la Misericordia, cuna de la pediatría en nuestra patria y recurso en salud en favor de las clases sociales menos favorecidas.

    Como extraña y feliz coincidencia el destino los ubicó a pocos metros de distancia el uno del otro, lo que facilitó para que sus labores fueran siempre acordes y se desarrollaran en perfecta armonía por cerca de tres lustros; esta circunstancia permite al final presentar a las generaciones futuras toda esa inmensa gama de realizaciones que hoy quedan en los campos de la salud y la ciencia. Tuve la inmensa fortuna de ser testigo cercano del diario desarrollo de sus actividades y es por esta razón por la cual no puedo retirar de la mente la capacidad de trabajo, dedicación y amor a los pacientes, al Hospital, de Rafael Barberi un gran filántropo, hombre tímido y sencillo, virtudes que lo hicieron más grande y admirable; no le faltó jamás el valor suficiente dentro de la mayor honestidad y respeto para convertirse en aguerrido defensor de la Institución y de sus colaboradores, también fué geperoso y bondadoso al otorgar el perdón y el olvido a sus ocasionales detractores.

    Ernesto Plata Rueda, el

  5. Functional diversity of benthic ciliate communities in response to environmental gradients in a wetland of Yangtze Estuary, China.

    Science.gov (United States)

    Xu, Yuan; Fan, Xinpeng; Warren, Alan; Zhang, Liquan; Xu, Henglong

    2018-02-01

    Researches on the functional diversity of benthic ecosystems have mainly focused on macrofauna, and studies on functional structure of ciliate communities have been based only on trophic- or size-groups. Current research was carried out on the changing patterns of classical and functional diversity of benthic ciliates in response to environmental gradients at three sites in a wetland in Yangtze Estuary. The results showed that changes of environmental factors (e.g. salinity, sediment grain size and hydrodynamic conditions) in the Yangtze Estuary induce variability in species composition and functional trait distribution. Furthermore, increased species richness and diversity did not lead to significant changes in functional diversity due to functional redundancy. However, salt water intrusion of Yangtze Estuary during the dry season could cause reduced functional diversity of ciliate communities. Current study provides the first insight into the functional diversity of ciliate communities in response to environmental gradients. Copyright © 2018 Elsevier Ltd. All rights reserved.

  6. Crecimiento y nutrición en preescolares de la ciudad de La Plata

    Directory of Open Access Journals (Sweden)

    Ranieri, José

    2001-01-01

    Full Text Available El objeto del presente trabajo es determinar el estado nutricional en una población proveniente del área urbanomarginal de La Plata compuesta por 215 niños de ambos sexos, de edad preescolar (2-5 años. Se relevaron las variables peso/edad; talla/edad y perímetro cefálico/edad incorporando además la variable knemométrica (tomada con pie de rey desde el punto superior de la rótula hasta el punto más bajo del talón. Los datos se procesaron mediante pruebas de Kolmogorov-Smirnov y Levene, análisis de varianza (ANOVA, correlación y regresión. Se calcularon diferencias porcentuales relativas entre medias (PDM. La muestra presentó distribución normal. Los puntajes Z indicaron valores entre -0.3 y 1.6. El ANOVA mostró para el factor edad diferencias significativas en todas las variables analizadas y para el factor sexo sólo en perímetro cefálico. Las correlaciones entre la variable knemométrica con las restantes variables fueron altamente significativas. Los resultados obtenidos permiten determinar que la población analizada presenta un estado nutricional óptimo respecto de los estándares del NCHS. La evaluación knemométrica constituye un buen indicador del crecimiento, dada su correspondencia con aquellos usualmente empleados.

  7. Integrating Geological map of the Plata Basin and adjacent areas: release Bulletin

    International Nuclear Information System (INIS)

    Preciozzi, F.; Spoturno Pioppo, J.; Medina, E.

    2001-01-01

    During the 1st Meeting of the Geological Surveys of the Southern Cone Countries, held in the city of Porto Alegre (Rio Grande do Sul - Brazil) in November 1995, it was born the idea of ​​a set of activities that it had aimed at developing integration , technical cooperation and scientific exchange between these institutions, resulting in a concrete proposal in order to develop a map of geological, metallogenic and hydrogeological basins of the Parana and Plata integration; which provide the basic information needed for the further development of mineral resources maps approach to groundwater, gold, ornamental stones, industrial minerals and precious stones; the development of exchange activities in the area of ​​the environment and the creation of a data bank of geological and mining of the countries involved in the program. This intention of working together was presented to SGT2, Theme of Geology and Mineral Resources MERCOSUR Commission, at its first meeting, held in Buenos Aires - Argentina, in April 1996, with the aim of transforming it into an official activity of this Commission, time that the delegations of the four States-Party endorsed the proposal. These opportunities were discussed and established parameters and standards for the execution of the works to be developed in the area between the parallel of 14oS and 38oS and meridians 44oW and 68oW (Figure 1), covering approximately 5,800,000 Km2 continental area, scale 1: 2,500,000, covering the entire basin of the River Plate. geological one, one and one hydrogeological mineral resources, plus a database of mineral resources, which serve as a source of information for the map of mineral resources: the generation of three maps was established as a goal. The official name for this project was established Maps

  8. Síntesis electroquímica de nanopartículas de plata en presencia de un surfactante neutro

    OpenAIRE

    Blandón, Lucas; Vázquez, Mario V.; Boannini, Elisa; Ballarin, Bárbara

    2015-01-01

    Muchas de las aplicaciones de las nanopartículas de platase encuentran en el área de la medicina como agentesantimicrobianos. Para evaluar la actividad antimicrobianade estos materiales, es importante garantizar que se encuentran estables y que los agentes estabilizantes seanbiocompatibles. Entre los métodos propuestos para lasíntesis de nanopartículas de plata se encuentran losmétodos electroquímicos, que han mostrado tener ventajasgracias a la facilidad para controlar las variables desíntes...

  9. Sistemas de calidad en turismo. Posibilidades y restricciones de su implementación en Mar del Plata

    OpenAIRE

    Castellucci, Daniela I.

    2011-01-01

    La tesis tiene como objetivos indagar en las empresas hoteleras, gastronómicas y de balnearios de la ciudad de Mar del Plata (Argentina), el nivel en que se encuentra su cultura de la calidad; e identificar cuáles son los factores determinantes en la toma de decisión para la implementación de Sistemas de Gestión de Calidad. Desde un enfoque cualitativo, y tomando la modalidad de estudio de casos múltiples, se analizan en dieciocho empresas de servicios turísticos, la cultura organizacional, d...

  10. Evaluación "In vitro" e "in vivo" de la seguridad de nanopartículas de plata

    OpenAIRE

    Ávalos Fúnez, Alicia

    2017-01-01

    El rápido desarrollo de la nanotecnología ha abierto la puerta a la obtención de productos y aplicaciones innovadoras para una amplia gama de sectores de la industria y el consumo. Se estima que de todos los nanomateriales utilizados en productos para el consumo, las nanopartículas de plata (AgNPs) son las que tienen un mayor grado de comercialización. Sin embargo, a pesar de las innumerables aplicaciones que presentan, poco se sabe sobre su toxicidad, planteando un riesgo para la salud human...

  11. Inventario de fuentes puntuales de contaminación potencial del agua subterranea: caso de estudio Mar del Plata

    OpenAIRE

    Massone, Héctor; Corleto, Bárbara; Albornoz, Daniel; Lima, Lourdes; Pertini, Ignacio; Damiano, Fernanda; Barilari, Agustina; Fresta, Paula

    2016-01-01

    La ciudad de Mar del Plata es la cabecera del Partido de General Pueyrredón, tiene una población de 620.000 habitantes y se abastece íntegramente del recurso hídrico subterráneo. Una parte importante del proceso de gestión de este recurso es la prevención de la contaminación; en este sentido, son variadas las metodologías de caracterización de carga contaminante; uno de sus aspectos es el modo de disposición, en el que pueden identificarse fuentes puntu...

  12. Representaciones sobre el aborto : Estudio de jóvenes de sectores pobres de la ciudad de La Plata (2012)

    OpenAIRE

    Caneva, Hernán Andrés

    2012-01-01

    En el presente trabajo se expondrán los avances de un estudio exploratorio de corte cualitativo que estoy realizando con motivo de finalizar mi tesina de grado en la carrera de Lic. Sociología. En dicho estudio me propongo conocer y analizar representaciones acerca del aborto de jóvenes (varones y mujeres) escolarizados de sectores pobres de la ciudad de La Plata durante 2012. La hipótesis de trabajo que orienta el estudio indica que la integración en espacios de socialización tales como l...

  13. Moessbauer studies of one representative hydromorphic soil of the coastal area of the Rio de La Plata

    Energy Technology Data Exchange (ETDEWEB)

    Guichon, B. A. [Universidad Nacional de La Plata, Instituto de Geomorfologia y Suelos (Argentina); Desimoni, J.; Mercader, R. C., E-mail: mercader@fisica.unlp.edu.ar [Universidad Nacional de La Plata, Departamento de Fisica, IFLP-CONICET, Facultad de Ciencias Exactas (Argentina); Imbellone, P. A. [Universidad Nacional de La Plata, Instituto de Geomorfologia y Suelos (Argentina)

    2010-01-15

    In the present work, we have applied Moessbauer spectroscopy as well as the traditional chemical analyses to assess the contents of different states of Fe in oxides and hydroxides in an Entisol soil from the Argentine coastal plain of the Rio de La Plata. Tentative assignments for the different Fe ion sites are proposed. Our findings show that the isomer shift and quadrupole splitting are sensitive to the changes detected in the Fe{sup 2+} contents of the soluble phase while others remain constant within the experimental uncertainties.

  14. Selección de dormideros por el estornino pinto (Sturnus vulgaris) en La Plata, Buenos Aires, Argentina

    OpenAIRE

    Girini, Juan Manuel; Palacio, Facundo Xavier; del Huerto, María del C.; Kuzmanich, Nicolás

    2016-01-01

    El Estornino Pinto (Sturnus vulgaris) es un ave introducida en Argentina que establece dormideros comunales durante la época no reproductiva. A pesar de ser una de las especies invasoras más perjudiciales del mundo, se conoce muy poco acerca de su ecología en Argentina. En este trabajo se caracterizaron los dormideros comunales del Estornino Pinto en la ciudad de La Plata con el objetivo de evaluar la selección del sitio de dormidero por parte de la especie. Se encontró un total de 34 dormide...

  15. Selección de dormideros por el Estornino Pinto (Sturnus vulgaris) en La Plata, Buenos Aires, Argentina

    OpenAIRE

    Girini, Juan M; Palacio, Facundo X; del Huerto, María del C; Kuzmanich, Nicolás

    2014-01-01

    El Estornino Pinto (Sturnus vulgaris) es un ave introducida en Argentina que establece dormideros comunales durante la época no reproductiva. A pesar de ser una de las especies invasoras más perjudiciales del mundo, se conoce muy poco acerca de su ecología en Argentina. En este trabajo se caracterizaron los dormideros comunales del Estornino Pinto en la ciudad de La Plata con el objetivo de evaluar la selección del sitio de dormidero por parte de la especie. Se encontró un total de 34 dormide...

  16. Las localidades menores del sur de Mar del Plata desde una perspectiva demogeográfica (1991-2001

    Directory of Open Access Journals (Sweden)

    Sofía Estela Ares

    2008-01-01

    Full Text Available En relación con el crecimiento demográfico de las localidades ubicadas al sur de Mar del Plata (Partido de General Pueyrredon el problema es establecer el aporte de los saldos vegetativos y de los saldos migratorios. Las bases de datos censales permiten la aproximación indirecta al comportamiento vegetativo; con respecto a las migraciones, no es posible calcular saldos de movilidad. Los resultados se obtuvieron mediante el procesamiento cuantitativo de datos censales y muestran un proceso de envejecimiento en las localidades mencionadas y la probable preeminencia del componente migratorio en el crecimiento demográfico.

  17. Urban transformations in the district of La Plata since the nineties. A compact or a diffuse city model?

    Directory of Open Access Journals (Sweden)

    Julieta Constanza Frediani

    2006-01-01

    Full Text Available In the last decade several studies done on the transformation of the city from compact to more scattered and fragmented have shown the concern for the effects the open and scattered city may have upon the environment. Although we consider that the urban models, "compact" and "diffuse", actually cannot be found in isolation, they are used to represent the extremes that relate the model of our city with these two models. The purpose of the present paper is to recognize in La Plata District, the behavioral pattern variable that causes the territorial conflicts in each of the models.

  18. Reptiles escamosos (Squamata del Pleistoceno Medio del Norte de la ciudad de Mar del Plata (provincia de Buenos Aires, Argentina

    Directory of Open Access Journals (Sweden)

    Santiago Brizuela

    2015-05-01

    Full Text Available In this study, we describe two fossil remains of squamate reptiles found in Middle Pleistocene outcrops at the northern marine cliffs of the city of Mar del Plata (Buenos Aires province. The specimens were found forming a taphocenosis with remains of other microvertebrates (amphibians, mammals and birds. The reptiles recognized in the association are represented by remains of an undetermined colubrid, and the anguid Ophiodes sp. This latter finding represents the first fossil record for the family Anguidae exhumed in Argentina.

  19. Equilibrios de precipitación. Influencia del pH sobre la solubilidad del acetato de plata. Problema interactivo.

    OpenAIRE

    Milla González, Miguel

    2015-01-01

    Se estudia como influye la variación del pH en la solubilidad de una sal cuya parte aniónica es una base débil. Es el caso del acetato de plata. Mediante una animación se muestra el desplazamiento del equilibrio hacia una mayor solubilización. El paso siguiente es encontrar una expresión sencilla que relaciona la solubilidad con el pH y se representa gráficamente dicha función mediante una hoja de cálculo.

  20. Turismo de congresos y reuniones en la ciudad de La Plata: Estado actual, tendencias y posibilidades de desarrollo

    OpenAIRE

    Herrera, Leandro Javier

    2014-01-01

    Año a año Argentina es elegida como sede de todo tipo de reuniones, una modalidad turística vista como una actividad económica rentable que crece sostenidamente a nivel mundial y nacional. El siguiente trabajo de investigación describe la situación actual de La Plata como ciudad sede de este fenómeno, los diferentes eventos realizados durante el año 2013 y características generales del consumidor principal de este segmento. Se realiza una conceptualización y contextualización del turism...

  1. Construcción de un edificio bajo la figura del fideicomiso en Mar del Plata, en 2008

    OpenAIRE

    Fagioli, Francisco

    2008-01-01

    Se desarrolló el caso particular de la construcción de un edificio de departamentos en la ciudad de Mar del Plata proponiendo la implementación de la figura del Fideicomiso y se analizaron las ventajas que ello representa para los Fiduciantes. El proyecto incluyó un análisis del mercado y comercialización de los servicios, la viabilidad técnica y la de gestión, la enumeración de inversiones y los requisitos necesarios para cumplir con las legislaciones vigentes, el análisis ...

  2. Nanopartículas de plata con potenciales aplicaciones en materiales implantables: síntesis, caracterización fisicoquímica y actividad bactericida

    OpenAIRE

    Flores, Constanza Y.

    2014-01-01

    El objetivo general del presente Trabajo de Tesis fue la preparación y caracterización de superficies sólidas modificadas con nanopartículas de plata con potenciales aplicaciones en Biomedicina. Para esto se optimizó el método de síntesis de nanopartículas de plata (NPs Ag) recubiertas con citrato, obteniendo NPs Ag monodispersas de 6 ± 2 nm de diámetro recubiertas con citrato y estables en medios acuosos. Asimismo, se estudió la inmovilización de estas NPs Ag sobre superficies de Ti/TiO2, en...

  3. Variación de la recarga entre La Plata y Santa Isabel (provincias de Buenos Aires y La Pampa - Argentina) : Propuesta metodológica

    OpenAIRE

    Hernández, Mario Alberto; Giai, Santiago B.

    1996-01-01

    Se analiza la recarga potencial de aguas subterráneas sobre un perfil entre La Plata y Santa Isabel (Buenos Aires y La Pampa). El mismo tiene la particularidad de ser perpendicular a las isohietas, extendiéndose desde una zona húmeda lindante con el río de la Plata, hasta otra de fuerte aridez y continentalidad, unos 900 km al Oeste. Algunos de los factores influyentes en el monto de la recarga tienen el mismo valor en todo el perfil, alcanzando su intervención igual peso en todas las local...

  4. Escenario de la presencia italiana en La Plata : El edificio del Banco de la provincia de Buenos Aires como objeto de análisis

    OpenAIRE

    Carbonari, Fabiana Andrea; Grandis, María Belén de

    2015-01-01

    El presente artículo se inscribe en el plan de trabajo de la Beca Interna de Entrenamiento en Investigación de la FAU denominada Italianos en la ciudad de La Plata. El caso del Banco Provincia de la ciudad de La Plata que, durante el ciclo lectivo 2015 desarrolla la Arq. María Belén de Grandis con dirección de la Esp. Arq. Fabiana Carbonari. La misma tiene por objetivo realizar el estudio histórico sistemático del Banco de la Provincia de Buenos Aires. En ese sentido, propone analizar las tra...

  5. El Proceso de precarización en el mercado de trabajo del Gran La Plata. Principales características y tendencias actuales (2003-2004

    Directory of Open Access Journals (Sweden)

    Héctor Luis Adriani

    2005-01-01

    Full Text Available The aim of this paper is to identify of the main features and trends of precarious work in Great La Plata, considering the current national economic dynamics. Taking as benchmark the "full" employment, different degress of precariousness can be found according to the lack of features that characterize said fullness. Thus, there would be a gradation of situations, from a maximum reference in the "full" employment to a minimum one in the absolute unemployment. The analysis is based on the information provide by a survey called Encuesta Permanente de Hogares (EPH, which comprises the time between the second semester in 2003 and the first one in 2004, since after their restructuring EPH only provides information on that period so far. The results show that in the region, precarious jobs amount to 39.3 of the economically active population in the first semester in 2004. If the unemployed are included, over 50 of the population undergo employment problems and there exists pressure of the demanding underemployed sector on the labor market. In the public sector, 16.4 of the people employed are precarized, and the percentage rises to 34 if the beneficiaries of unemployment programs are included. In the private sector, precarious employment reaches 54. Regarding the evolution of per capita income, the levels reached are below those earned before the 2002 devaluation, even within the groups of employed people whose purchasing power improved between 2003 and 2004. The main contributions of this paper lie in the identification, quantification and characterization of precarious employment in the region in the post-devaluation period through the analysis of the EPH Data Base.

  6. What is left behind when the lights go off? Comparing the abundance and composition of litter in urban areas with different intensity of nightlife use in Mar del Plata, Argentina.

    Science.gov (United States)

    Becherucci, Maria Eugenia; Seco Pon, Juan Pablo

    2014-08-01

    Nightlife activities represents an important source of urban litter; the latter often being left behind or abandoned in public places and streets. Mar del Plata is a very important city on the Atlantic coast of Argentina and is the main tourism destination in the South Atlantic region of South America. However, few studies on urban litter related to nightlife activities have been conducted in the area. Here we assessed (i) the abundance and composition of litter, and (ii) the spatial and temporal variations of its abundance, diversity, richness and evenness in urbanized areas with different intensity of nightlife activities from April 2008 to March 2009. An overall of 13,503 items were counted. Around 92% of the total litter was comprised by cigarette butts, papers and plastics. We found significant spatial differences in the abundance of litter between sampling sites, with the greatest amounts of litter at the Alem site followed by the Hipólito site (both with an intensive nightlife activity) compared with the Chauvin site (a quiet high-income neighborhood). The composition of litter of the Alem and the Hipólito sites was relatively similar and both sites differ with respect to the Chauvin site. Cigarette butts, papers, and plastics were the items that contributed most to the dissimilarity between sampling sites. The diversity of litter was the single community parameter that significantly differed from the other seasons. We discussed the potential effect of nightlife activities on the amounts and quality of urban litter in the city of Mar del Plata. Copyright © 2014 Elsevier Ltd. All rights reserved.

  7. Marine geology of the St. Lawrence Estuary

    Energy Technology Data Exchange (ETDEWEB)

    St-Onge, Guillaume [Canada Research Chair in Marine Geology, Institut des sciences de la mer de Rimouski (ISMER) and GEOTOP Research Center, 310 allee des Ursulines, Rimouski, Quebec, G5L 3A1 (Canada); Duchesne, Mathieu J [Geological Survey of Canada, Quebec Division, 490 de la Couronne, Quebec City, Quebec, G1K 9A9 (Canada); Lajeunesse, Patrick, E-mail: guillaume_st-onge@uqar.qc.ca [Departement de geographie and Centre d' etudes nordiques, Universite Laval, Quebec City, Quebec, G1V 0A6 (Canada)

    2011-05-15

    The St. Lawrence Estuary, Eastern Canada, contains a very thick (>450 m) Quaternary sedimentary sequence. The results from recently conducted geophysical surveys in conjunction with piston coring indicate that these sediments were deposited under very high sedimentation rates, sometimes as high as {approx}30 m/ka during the last deglaciation. Results also reveal evidence of large submarine landslides during the Holocene, changes in sedimentation rates and the significant role of submarine canyons and channels to transfer sediments from the coast to the deeper marine environment. Finally, this paper highlights the presence of more than 1900 pockmarks on the seafloor of the St. Lawrence Estuary and discusses their possible origins: active hydrocarbon seeps in the Laurentian Channel and biogenic gas seepage on the northwestern shoulder of the Laurentian Channel.

  8. Marine geology of the St. Lawrence Estuary

    International Nuclear Information System (INIS)

    St-Onge, Guillaume; Duchesne, Mathieu J; Lajeunesse, Patrick

    2011-01-01

    The St. Lawrence Estuary, Eastern Canada, contains a very thick (>450 m) Quaternary sedimentary sequence. The results from recently conducted geophysical surveys in conjunction with piston coring indicate that these sediments were deposited under very high sedimentation rates, sometimes as high as ∼30 m/ka during the last deglaciation. Results also reveal evidence of large submarine landslides during the Holocene, changes in sedimentation rates and the significant role of submarine canyons and channels to transfer sediments from the coast to the deeper marine environment. Finally, this paper highlights the presence of more than 1900 pockmarks on the seafloor of the St. Lawrence Estuary and discusses their possible origins: active hydrocarbon seeps in the Laurentian Channel and biogenic gas seepage on the northwestern shoulder of the Laurentian Channel.

  9. Deschutes estuary feasibility study: hydrodynamics and sediment transport modeling

    Science.gov (United States)

    George, Douglas A.; Gelfenbaum, Guy; Lesser, Giles; Stevens, Andrew W.

    2006-01-01

    Continual sediment accumulation in Capitol Lake since the damming of the Deschutes River in 1951 has altered the initial morphology of the basin. As part of the Deschutes River Estuary Feasibility Study (DEFS), the United States Geological Survey (USGS) was tasked to model how tidal and storm processes will influence the river, lake and lower Budd Inlet should estuary restoration occur. Understanding these mechanisms will assist in developing a scientifically sound assessment on the feasibility of restoring the estuary. The goals of the DEFS are as follows. - Increase understanding of the estuary alternative to the same level as managing the lake environment.

  10. Conducta Innovadora en el Sector Industrial: El caso de Pequeñas y Medianas Empresas en Mar del Plata, Argentina (Innovating behavior in the Industrial Sector: Small and medium size enterprises in Mar del Plata, Argentina

    Directory of Open Access Journals (Sweden)

    Lucía Mercedes Mauro

    2012-12-01

    Full Text Available El cambio tecnológico es central en una estrategia de desarrolloeconómico endógeno, y su abordaje exitoso por partede las empresas requiere de un entorno a partir del que sepromueva y acompañe dicho proceso. El objetivo del estudioes comprender, desde una óptica territorial, la conducta innovadorade empresas industriales. Para ello se analiza el caso decuatro PYMES en segmentos con alto potencial de crecimientoeconómico de la ciudad de Mar del Plata (Argentina en el períodopost-convertibilidad. Se concluye que estas empresas tienenun marcado perfil innovador, aún cuando no se encuentraconsolidado el sistema de innovación local, falta de personalcon las competencias necesarias para llevar adelante el cambiotecnológico, y se observan desconexiones entre el sectorpúblico y el privado.   ABSTRACT Technological changes are paramount for an endogenous economicdevelopment programs, and require that companies developingit operate in an environment promoting and nurturing suchprograms. This study´s goal is to understand the innovation behaviorof industrial companies from a territorial point of view. To thatend we analyzed four SMEs operating, in a high economic growthsegment after the conversion period in Mar del Plata, Argentina.It was deduced that said companies possess an innovative profile(even despite the fact that the local innovation support system isnot fully consolidated, lack personnel with the appropriate knowledgeto pursue technological changes, and there are mismatchesbetween the private and public sectors.

  11. Los ejemplares tipo de Dryopidae, Elmidae, Limnichidae y Psephenidae (Coleoptera: Byrrhoidea, depositados en la colección del Museo de La Plata The types of Dryopidae, Elmidae, Limnichidae and Psephenidae (Coleoptera: Byrrhoidea housed at the Museo de La Plata

    Directory of Open Access Journals (Sweden)

    Liliana A. Fernández

    2004-07-01

    Full Text Available Se examinaron los ejemplares tipo depositados en la colección de la División Entomología del Museo de La Plata, pertenecientes a diversas especies nominales de Byrrhoidea: Dryopidae (1 especie, 1 ejemplar tipo, Elmidae (4, 9, Limnichidae (29, 47 y Psephenidae (1, 2. El material tipo fue estudiado por los siguientes autores: Pic, Spangler, Spangler & Brown, Spangler & Perkins, Spangler & Santiago, Spilman y Wooldridge. Para cada taxón se indica la publicación original, datos de colección y condición del material.The types of species of Byrrhoidea (Coleoptera housed in the collection of the División Entomología of Museo de La Plata were examined and listed. They belong to 35 species distributed in the families Dryopidae (1 species, 1 type, Elmidae (4, 9, Limnichidae (29, 47 and Psephenidae (1, 2. The types were described by Pic, Spangler, Spangler & Brown, Spangler & Perkins, Spangler & Santiago, Spilman, and Wooldridge. For each taxon, complete information about categories of types, reference original descriptions, collection data and specimen condition are given.

  12. Impact of boat generated waves over an estuarine intertidal zone of the Seine estuary (France)

    Science.gov (United States)

    Deloffre, Julien; Lafite, Robert

    2015-04-01

    Water movements in macrotidal estuaries are controlled by the tidal regime modulated seasonally by the fluvial discharge. Wind effect on hydrodynamics and sediment transport is also reported at the mouth. Besides estuaries are frequently man altered our knowledge on the human impact on hydrodynamics and sediment transport is less extended. As an example on the Seine estuary (France) port authorities have put emphasis on facilitating economic exchanges by means of embankment building and increased dredging activity over the last century. These developments led to secure sea vessel traffic in the Seine estuary but they also resulted in a change of estuarine hydrodynamics and sediment transport features. Consequences of boat generated waves are varied: increased water turbidity and sediment transfer, release of nutrient and contaminants in the water column, harmful to users, ecosystems and infrastructures generating important maintenance spending. The aim of this study is to analyse the impact of boat generated waves on sediment transport over an intertidal area. The studied site is located on the left bank in the fluvial part of the Seine estuary. On this site the maximum tidal range ranges between 1.25 and 3.5m respectively during neap and spring tide. The sampling strategy is based on continuous ADV acquisition at 4Hz coupled with turbidimeter and altimeter measurements (1 measurement every minute) in order to decipher sediment dynamics during one year. Our results indicate that sediment dynamics are controlled by river flow while medium term scale evolution is dependent on tidal range and short term dynamics on sea-vessels waves. 64% of boat passages generated significant sediment reworking (from few mm.min-1 to 3cm.min-1). This reworking rate is mainly controlled by two parameters: (i) water height on the site and (ii) vessels characteristics; in particular the distance between seabed and keel that generate a Bernoulli wave (with maximum amplitude of 0.6m

  13. Miradas Caleidoscópicas sobre el Chagas. Una experiencia educativa en el Museo de La Plata

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    Mariana Sanmartino

    2012-01-01

    Full Text Available Presentamos resultados y reflexiones en torno a la experiencia "Semana del Chagas en el Museo de La Plata" (La Plata, Provincia de Buenos Aires, Argentina realizada en mayo de 2011. La propuesta tuvo como objetivo la difusión y sensibilización acerca de la problemática del Chagas desde una mirada integral. Las actividades incluyeron una muestra de obras plásticas; la proyección de materiales audiovisuales innovadores; talleres con estudiantes de escuelas primarias y secundarias de la zona; charlas abiertas a cargo de especialistas; la presentación y distribución de materiales didácticos a docentes de escuelas; así como el desarrollo de actividades destinadas al público general. La evaluación de la experiencia es altamente satisfactoria, y de la reflexión sobre lo transitado -durante la organización y en la implementación- surgen múltiples aprendizajes tanto para participantes como para organizadores, de lo cual se desprende el interés por compartir la propuesta y la posibilidad de adecuarla a otros contextos.

  14. La introducción de las telecomunicaciones eléctricas en el Río de la Plata

    Directory of Open Access Journals (Sweden)

    Ariel Sar

    2013-03-01

    Full Text Available Las telecomunicaciones eléctricas fueron introducidas en las repúblicas del Río de la Plata entre 1864 y 1866. Primero Paraguay instaló el ferrocarril, la telegrafía eléctrica y una fundición de acero para fabricar armas y tecnología pesada. A los pocos meses, capitales británicos instalaron una red telegráfica eléctrica entre la Argentina y Uruguay, en el marco de una estrategia de desarrollo económico y de dominación imperial para establecer redes de expansión global conformadas por los telégrafos, los puertos y los ferrocarriles. Estos eventos tecnológicos se produjeron en el marco de un conflicto creciente entre facciones de Argentina, Brasil y Uruguay que desembocaron en la Guerra de la Triple Alianza contra Paraguay, conflagraciones de las que participaron, de una u otra manera, Gran Bretaña y Francia. Las guerras de soberanía rioplatense y la competencia entre potencias europeas impulsa, pues, una revolución tecnológica en el Plata en el campo de las comunicaciones.

  15. La industria del Gran La Plata según el último Censo Nacional Económico

    Directory of Open Access Journals (Sweden)

    Diego Arturi

    2012-12-01

    Full Text Available El artículo tiene como objetivo caracterizar el sector industrial del Gran La Plata en base a información del último Censo Nacional Económico (CNE 2004/2005. En una primer parte se identifican las principales características del sector industrial a escala nacional en los períodos neoliberal y posconvertibilidad, a partir de bibliografía especializada y análisis de series estadísticas e informes técnicos. En una segunda parte se analiza el sector industrial del Gran La Plata en base a entrevistas a informantes calificados y a los datos censales según cantidad de establecimientos, puestos de trabajo ocupados, rama de actividad, tamaño de los locales industriales, productividad y especialización industrial de los municipios; asimismo se realiza una aproximación a niveles de intensidad tecnológica por rama. A partir de este análisis se pueden destacar las siguientes conclusiones: predominio de las micro y pequeñas empresas, productividad superior al promedio nacional, escaso aporte de las ramas de alta intensidad tecnológica y ausencia de especialización que impide definir un perfil industrial marcado.

  16. Mar del Plata (Argentina: la ciudad balnearia de los porteños en el Atlántico suroccidental

    Directory of Open Access Journals (Sweden)

    Yvanne Bouvet

    2005-01-01

    Full Text Available Nacida a fines del siglo 19, Mar del Plata ha devenido —en el término de un siglo— en balneario por excelencia de Buenos Aires y de la Argentina en general. La cultura estival de la playa la ha hecho evolucionar desde un turismo elitista hacia un turismo de masas, impulsando el desarrollo de espacios y estructuras destinadas a alojamiento y ocio para cerca de 3 millones de personas cada año. Con un espacio urbano fuertemente segregativo y en expansión, el litoral está sometido a una fuerte presión antrópica, a una erosión contínua y a una degradación en la calidad de sus aguas. La crisis social, económica y política que atraviesa Argentina crea condiciones poco favorables para la actividad turística y ensombrece el futuro de Mar del Plata.

  17. Hydro- and sediment dynamics in the estuary zone of the Mekong Delta: case study Dinh An estuary.

    Science.gov (United States)

    Tran, Anh Tuan; Thoss, Heiko; Gratiot, Nicolas; Dussouillez, Philippe; Brunier, Guillaume; Apel, Heiko

    2017-04-01

    The Mekong River is the tenth largest river in the world, covers an area of 795,000 km2, 4400km in length, the main river flows over the six countries including: China, Myanmar, Thailand, Laos, Cambodia and Vietnam. Its water discharge is 470 km3year-1 and the sediment discharge is estimated about 160 million ton year-1. The sediment transported by the Mekong River is the key factor in the formation and development of the delta. It is a vital factor for the stability of the coastline and river banks. Furthermore it compensates land subsidence by floodplain deposition, and is the major natural nutrient source for agriculture and aquaculture. However, only a few studies were conducted to characterize and quantify sediment properties and process in the Delta. Also the morphodynamic processes were hardly studied systematically. Hence, this study targets to fill some important and open knowledge gaps with extensive field works that provide important information about the sediment properties and hydrodynamic processes in different seasons Firstly three field survey campaigns are carried out along a 30 km section of the Bassac River from the beginning of Cu Lao Dung Island to Dinh An estuary in 2015 and 2016. During the field campaign, the movement of the salt wedge and the turbidity were monitored by vertical profiles along the river, as well as discharge measurements by ADCP were carried out at three cross sections continuously for 72 hours. The extension of the salt wedge in the river was determined, along with mixing processes. The movement and dynamics observed under different flow conditions indicate that sediment was pumped during low flow upwards the river, while during high flow net transport towards the sea dominated. Also a distinct difference in the sediment properties in the different seasons was observed, with a general tendency towards a higher proportion of coarser particles in the high flow season. These quantitative results give insights into the

  18. Multivariate statistical study of heavy metal enrichment in sediments of the Pearl River Estuary

    International Nuclear Information System (INIS)

    Liu, W.X.; Li, X.D.; Shen, Z.G.; Wang, D.C.; Wai, O.W.H.; Li, Y.S.

    2003-01-01

    Multivariate statistical analysis identified the heavy metal accumulation layers of sediment profiles and showed the various sources of metals in the estuary. - The concentrations and chemical partitioning of heavy metals in the sediment cores of the Pearl River Estuary were studied. Based on Pearson correlation coefficients and principal component analysis results, Al was selected as the concentration normalizer for Pb, while Fe was used as the normalizing element for Co, Cu, Ni and Zn. In each profile, sections with metal concentrations exceeding the upper 95% prediction interval of the linear regression model were regarded as metal enrichment layers. The heavy metal accumulation mainly occurred at sites in the western shallow water areas and east channel, which reflected the hydraulic conditions and influence from riparian anthropogenic activities. Heavy metals in the enrichment sections were evaluated by a sequential extraction method for possible chemical forms in sediments. Since the residual, Fe/Mn oxides and organic/sulfide fractions were dominant geochemical phases in the enriched sections, the bioavailability of heavy metals in sediments was generally low. The 206 Pb/ 207 Pb ratios in the metal-enriched sediment sections also revealed the influence of anthropogenic sources. The spatial distribution of cumulative heavy metals in the sediments suggested that the Zn and Cu mainly originated from point sources, while the Pb probably came from non-point sources in the estuary

  19. Shifting baselines in the Ems Dollard estuary: A comparison across three decades reveals changing benthic communities

    Science.gov (United States)

    Compton, Tanya J.; Holthuijsen, Sander; Mulder, Maarten; van Arkel, Maarten; Schaars, Loran Kleine; Koolhaas, Anita; Dekinga, Anne; ten Horn, Job; Luttikhuizen, Pieternella C.; van der Meer, Jaap; Piersma, Theunis; van der Veer, Henk W.

    2017-09-01

    At a time when there is a growing discussion about the natural state of estuaries, a comparison of macrozoobenthos communities from two surveys conducted 30 years apart in the Ems Dollard estuary, in the eastern Wadden Sea, The Netherlands, provides a unique opportunity to compare changes over time. As expected, our comparison revealed a gradient in species composition from land (the Dollard) to sea (the Outer Ems) at both points in time, with brackish species in the Dollard and more marine species in the Outer Ems (Wadden Sea). Total richness increased over time; however, this mainly reflected the immigration of new species and sampling differences. In the Dollard, total biomass declined over time, most likely reflecting de-eutrophication in this area. Strikingly, at the meeting point between the sea and the brackish Dollard, i.e. the Inner Ems, the community composition changed from one dominated by bivalves (1970s) to one dominated by worms (since 2009). This change involved a reduction in total biomass, mainly of Mya arenaria, and immigration of polychaete worms (Marenzellaria viridis and Alitta succinea). In the Outer Ems, an increase in total biomass was observed, associated with the recent successful recruitment of Cerastoderma edule. This comparison highlights that historical data provides useful insights at large spatial scales. However, a full understanding of the complex dynamics of estuaries requires an analysis of continuous long-term monitoring series.

  20. Combined Stable Carbon Isotope and C/N Ratios as Indicators of Source and Fate of Organic Matter in the Bang Pa kong River Estuary, Thailand

    International Nuclear Information System (INIS)

    Boonphakdee, Thanomsak; Kasai, Akihide; Fujiwara, Tateki; Sawangwong, Pichan; Cheevaporn, Voravit

    2007-08-01

    Full text: Stable carbon isotopes and C/N ratios of particulate organic matter (POM) in suspended solids and surficial sediment were used to define the spatial and temporal variability in an anthropogenic tropical river estuary, the Bang Pa kong River Estuary. Samples were taken along salinity gradients during the four different river discharges in the beginning, high river discharge and at the end of the wet season, and low river discharge during the dry season. The values of [C/N]a ratio and d13C in the river estuary revealed significant differences from those of the offshore station. Conservative behaviors of [C/N]a and d13C in the estuary during the wet season indicated major contribution of terrigenous C3 plants derived OM. By contrast, during the dry season, marine input mainly dominated OM contribution with an evidence of anthropogenic input to the estuary. These compositions of the bulk sedimentary OM were dominated by paddy rice soils and marine derived OM during the wet and dry seasons, respectively. These results show that the combined stable carbon isotopes and C/N ratios can be used to identify the source and fate of OM even in a river estuary. This tool will be useful to achieve sustainable management in coastal zone

  1. Multiproxies (benthic foraminifera, ostracods and biopolymers approach applied to identify the environmental partitioning of the Guadiana River Estuary (Iberian Peninsula

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    Lazaro Luiz Mattos Laut

    2016-04-01

    Full Text Available The Guadiana River is the fourth longest river in Europe and is a natural frontier between southern Portugal and Spain. This river was historically used to transport minerals exploited in the region since the Roman Empire and therefore suffered human interventions that have been intensified after the industrial revolution. The Guadiana River has in its limits the Guadiana Valley Natural Park, which is of great value for the Conservation of Geobiodiversity. This study mainly aims to identify zones with the environmental characteristics in the estuarine area of the Guadiana River based on the distribution and ecology of microorganisms (ostracods and foraminifera associated with physicochemical parameters and sedimentological and geochemical (carbohydrate, lipid, protein, total organic carbon and total sulfur data. Fifty-five foraminifera taxa were identified along the estuary with dominance of Ammonia tepida and Miliammina fusca and 13 ostracods taxa with dominance Leptocythere lacertosa and Loxoconcha elliptica. Detrended correspondence analysis (DCA performed using biotic and abiotic variables indicated that pH, grain size, total organic carbon (TOC and lipids were the most influent factors in the distribution of these organisms. Four zones were identified in the Guadiana River estuary: i Low estuary - region with the largest marine influence with sandy sediment, higher salinity and total sulfur and mainly represented by the dominance of estuarine species of foraminifera (Ammonia tepida and Cribroelphidium vadescens and by the ostracods (Darwinula stevensoni, Semicytherura sulcata and Urocythereis oblonga; ii Intermediate estuary - region characterized by neutral pH and sandy sediment enriched in carbohydrates; this region is characterized by the presence of the ostracods species Cytherois fischeri and Neocytherideis subulata and by calcareous and agglutinated species in foraminiferal assemblages; iii Upper estuary - silt, high TOC, proteins and

  2. Bronces y plata tartéssicos de Alhonoz y su hinterland

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    Luis Alberto LÓPEZ PALOMO

    2009-12-01

    Full Text Available RESUMEN: En este artículo se ofrece una síntesis de los objetos metálicos obtenidos en las excavaciones del yacimiento sevillano de Alhonoz a lo largo de las campañas de 1973-75, 1977 y 1978 y se hace mención de otros hallazgos localizados casualmente a orillas del río Genil, entre el yacimiento de Alhonoz y el de Los Castellares (término de Puente Genil, provincia de Córdoba. Las piezas halladas en Alhonoz son: un thymaterion de bronce, no completo, de tipo chipriota, idéntico al que el profesor Karageorghis da a conocer procedente de Angolemi, dentro del tipo B-2 de la sistematización de Almagro Gorbea, que lo fecha hacia el siglo VII-VI a. C , una pequeña figurilla de la diosa Minerva y otros pequeños objetos también broncíneos, de las mismas excavaciones. Se publica también en este artículo un exvoto de plata, muy interesante, que ha sido calificado como «los ojos de Astarté» y que tiene muchas resonancias en el mundo fenicio. Por último se publican otros objetos de bronce procedentes de diferentes lugares cercanos a Alhonoz, y del mismo ambiente arqueológico.ABSTRACT: In this article a synthesis is offered of the metalics objets obtained at the excavations of the Sevillian deposit of Alhonoz during the 1973-75, 1977 and 1978 campaings. And another discovery is mentioned, casually found by the Genii riverside, between the deposits of Alhonoz and Los Castellares (municipal district of Puente Genii, Córdoba province. The pieces discovered at Alhonoz are: an incomplete bronze thymaterion of a Cypriot type, identical to the one made known by profesor Karageorghis, coming from the type B-2 of Almagro Gorbea systematization, which he dates at about the seventh-sixth centuries B.C., a little figure of Minerva goddess, and some other objecrs, also bronzed, from the same excavations. It is also published, in this article, a very interesting silver Ex-voro which has been qualified. Lastly, other bronze objets are published from

  3. Experimental use of Land Surface Models in the La Plata Basin

    Science.gov (United States)

    Goncalves, L.; de Mattos, J. Z.; Sapucci, L. F.; Herdies, D. L.; Berbery, E. H.

    2009-12-01

    Soil moisture is a key variable that controls the partitioning between sensible and latent heat flux, and under favorable conditions, it can modulate precipitation. The overlying boundary layer can be affected by soil moisture anomalies when persisting for an enough period of time. Several studies have shown the influence of surface processes in the South American atmospheric circulation and precipitation patterns. However the absence of a comprehensive observation network over that region represents a disadvantage for determining and quantifying memory and coupling between the land surface and the atmosphere. The La Plata Basin (LPB) in southeastern South America is recognized as an area of great importance for the economic and social development of several countries. Vast areas of this basin have experienced changes in land cover conditions due to the expansion of the agriculture (replacing natural vegetation), but also due to changes in crop types. This work presents results from an ensemble of four land surface models (Noah, CLM, MOSAIC and SiB2) used for climatic characterization of the past 30 years of soil moisture and temperature over the LPB. The Modern Era Retrospective-Analysis for Research and Applications (MERRA), from NASA’s Global Modeling and Assimilation Office (GMAO) was downscaled to be used to force the land surface models at 10Km, 3-hourly resolutions. Two sets of runs were made for this study: first, the LSMs were forced using reanalysis data to characterize the climatological states at coarse resolution, and second, the models were run using South American LDAS forcing fields from 2000 until present at higher resolution. The resulting spread among the different models was used as a measure of uncertainty in the initial states. In particular, the surface states derived from the Noah model were rescaled and used as initial conditions for atmospheric model simulations using the coupled ETA/Noah models. The control run was performed using

  4. Distribución espacial de las parasitosis intestinales en la ciudad de La Plata, Argentina

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    María I Gamboa

    2014-10-01

    Full Text Available El análisis de las parasitosis a diferentes escalas (regional, local se facilita por el Geographic Information System (GIS, que permite identificar áreas con distinto grado de vulnerabilidad. El objetivo del trabajo fue analizar la distribución espacial de las parasitosis intestinales en el partido de La Plata, estableciendo su relación con las condiciones socio-ambientales para identificar áreas con diferente riesgo epidemiológico. Se completó una encuesta epidemiológica y se tomaron muestras seriadas de materia fecal, analizadas por la técnica de Ritchie. Se calcularon niveles de precariedad y vulnerabilidad (Iv, y se compararon con los resultados parasitológicos. Se analizaron parasitológica y ambientalmente 653 personas, de las cuales 585 (89.6% eran niños y 68 (10.4% adultos. El análisis indicó que los más vulnerables (Iv = 3-4 estaban en el sector con menor acceso a servicios de infraestructura urbana. El índice se encontró fuertemente asociado a la prevalencia total de parasitosis intestinales y a las 4 especies patógenas asociadas a la contaminación fecal del ambiente: Trichuris trichiura, Ascaris lumbricoides, Hymenolepis nana y Giardia lamblia (p < 0.01. Enterobius vermicularis, parásito no vinculado a la condición sanitaria de sus hospedadores, no se asoció al Iv. Hubo asociación estadística entre precariedad y parasitosis y se halló que a mayor Iv mayor frecuencia de parasitosis (p < 0.01. El uso de GIS permitió zonificar las variables socioambientales en un gradiente creciente de condiciones desfavorables y su relación con la presencia de especies patógenas. La continuidad de estos estudios en diferentes regiones de Argentina contribuye a la determinación de áreas en riesgo sanitario.

  5. Material tipo de la Colección de Herpetología del Museo de La Plata, Buenos Aires, Argentina

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    Ferraro, Daiana Paola

    2005-12-01

    Full Text Available El Museo de la Plata (Buenos Aires, República Argentina se fundó en 1889, y la colección herpetológica comenzó a funcionar poco tiempo después, bajo la responsabilidad deJulio G. Koslowsky. En esta contribución se listan los ejemplares tipo de Anfibios y Reptiles depositados en la colección herpetológica del Museo de La Plata. El material tipo depositado corresponde a 32 especies descriptas desde 1895 hasta la actualidad, incluyendo: 14 holotipos, 115 paratipos, 4 lectotipos, 22 paralectotipos, 1 neotipo y 12 sintipos (sin incluir los ejemplares extraviados. Se proporciona, para cada taxón, la información completa referida a estatus de cada ejemplar tipo, sexo, datos de recolección y modificaciones taxonómicas posteriores. The La Plata Museum (Buenos Aires, República Argentina was founded on 1889, and after a little time, the herpetological collection started under the responsibility of Julio G. Koslowsky. In this paper the type specimens of Amphibia and Reptilia housed in the collection of the Herpetology Section at the La Plata Museum are listed. These type materials correspondto 32 species described since 1895 until nowadays, and include: 14 holotypes, 115 paratypes, 4 lectotypes, 22 paralectotypes, 1 neotype and 12 sintypes (this list does not include lost specimens. Complete data about taxonomic status, sex, collection data, and subsequent taxonomic changes are given for each taxon.

  6. Sources and distribution of yttrium and rare earth elements in surface sediments from Tagus estuary, Portugal.

    Science.gov (United States)

    Brito, Pedro; Prego, Ricardo; Mil-Homens, Mário; Caçador, Isabel; Caetano, Miguel

    2018-04-15

    The distribution and sources of yttrium and rare-earth elements (YREE) in surface sediments were studied on 78 samples collected in the Tagus estuary (SW Portugal, SW Europe). Yttrium and total REE contents ranged from 2.4 to 32mg·kg -1 and 18 to 210mg·kg -1 , respectively, and exhibited significant correlations with sediment grain-size, Al, Fe, Mg and Mn, suggesting a preferential association to fine-grained material (e.g. aluminosilicates but also Al hydroxides and Fe oxyhydroxides). The PAAS (Post-Archean Australian Shale) normalized patterns display three distinct YREE fractionation pattern groups along the Tagus estuary: a first group, characterized by medium to coarse-grained material, a depleted and almost flat PAAS-normalized pattern, with a positive anomaly of Eu, representing one of the lithogenic components; a second group, characterized mainly by fine-grained sediment, with higher shale-normalized ratios and an enrichment of LREE relative to HREE, associated with waste water treatment plant (WWTP) outfalls, located in the northern margin; and, a third group, of fine-grained material, marked by a significant enrichment of Y, a depletion of Ce and an enrichment of HREE over LREE, located near an inactive chemical-industrial complex (e.g. pyrite roast plant, chemical and phosphorous fertilizer industries), in the southern margin. The data allow the quantification of the YREE contents and its spatial distribution in the surface sediments of the Tagus estuary, identifying the main potential sources and confirming the use of rare earth elements as tracers of anthropogenic activities in highly hydrodynamic estuaries. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. Nutrient input through submarine groundwater discharge in two major Chinese estuaries: the Pearl River Estuary and the Changjiang River Estuary

    Science.gov (United States)

    Liu, Jianan; Du, Jinzhou; Wu, Ying; Liu, Sumei

    2018-04-01

    In this study, we used a 224Ra mass balance model to evaluate the importance of submarine groundwater discharge (SGD) for the budgets of biogenic elements in two major Chinese estuaries: the Pearl River Estuary (PRE) and the Changjiang River Estuary (CRE). The apparent water age in the PRE was estimated to be 4.8 ± 1.1 days in the dry season and 1.8 ± 0.6 days in the wet season using a physical model based on the tidal prism. In the dry season, the water age in the CRE was estimated to be 11.7 ± 3.0 days using the 224Ra/223Ra activities ratios apparent age model. By applying the 224Ra mass balance model, we obtained calculations of the SGD flow in the PRE of (4.5-10) × 108 m3 d-1 (0.23-0.50 m3 m-2 d-1) and (1.2-2.7) × 108 m3 d-1 (0.06-0.14 m3 m-2 d-1) in the dry season and wet season, respectively, and the estimated SGD flux was (4.6-11) × 109 m3 d-1 (0.18-0.45 m3 m-2 d-1) in the dry season of the CRE. In comparison with the nutrient fluxes from the rivers, the SGD-derived nutrient fluxes may play a vital role in controlling the nutrient budgets and stoichiometry in the study areas. The large amount of dissolved inorganic nitrogen and phosphorus fluxes together with high N: P ratios into the PRE and CRE would potentially contribute to eutrophication and the occurrence of red tides along the adjacent waters.

  8. Nutritional condition of fish larvae in South African estuaries: an ...

    African Journals Online (AJOL)

    Nutritional condition of fish larvae in South African estuaries: an appraisal of three biochemical methods. D Costalago, N Strydom, C Frost. Abstract. Estuaries are exposed to a number of threats and many South African estuarine systems are functionally and structurally altered. The extent to which fish are affected by these ...

  9. Columbia Estuary Ecosystem Restoration Program. 2012 Synthesis Memorandum

    Science.gov (United States)

    2013-01-01

    LCFRB Lower Columbia Fish Recovery Board LCRE lower Columbia River and estuary LCREP Lower Columbia River Estuary Partnership LWD large woody debris...hydraulic reconnections, channel creation, large woody debris [ LWD ] placement) have restored a total of 3152 acres since 2001. If land acquisition...fencing, invasive plant removal, native replanting. Mirror Lake 208 Culvert replaced with a bridge, riparian restoration, LWD enhancement, culvert

  10. Tillamook Estuary Case Study: Local Drivers Influencing Coastal Acidification

    Science.gov (United States)

    US EPA initiated a study in the Tillamook estuary and watershed focused on the impact of changes in watershed land use, ocean conditions, and weather on estuarine water quality and ecosystem goods and services production within the estuary. This project is a collaboration betwee...

  11. Fish abundance and distribution in the Gamtoos estuary with notes ...

    African Journals Online (AJOL)

    favourably with other larger systems like the Sundays, Bashee and Kei estuaries. .... as well as the use of pesticides undoubtedly affects water quality in the ... Methods. Catch per unit effort (CPUE) of fish in the Gamtoos estuary was obtained ...

  12. Relation between tidal damping and wave celerity in estuaries

    NARCIS (Netherlands)

    Savenije, H.H.G.; Veling, E.J.M.

    2005-01-01

    Observations in estuaries indicate that an amplified tidal wave moves considerably faster than is indicated by the classical equation for wave propagation. Similarly, the celerity of propagation is lower if the tidal wave is damped. This phenomenon is clearly observed in the Schelde estuary (located

  13. Zooplankton community changes in Nhlabane estuary, South Africa ...

    African Journals Online (AJOL)

    made impacts since 1977, when the lake and estuary were separated by the construction of a barrage. More recent man-made events included the construction of temporary sand walls, mid-way along the estuary, to allow crossing of a mining ...

  14. Tidal exchange between a freshwater tidal marsh and an impacted estuary: the Scheldt estuary, Belgium

    NARCIS (Netherlands)

    van Damme, S.; Dehairs, F.; Tackx, M.; Beauchard, O.; Struyf, E.; Gribsholt, B.; van Cleemput, O.; Meire, P.

    2009-01-01

    Tidal marsh exchange studies are relatively simple tools to investigate the interaction between tidal marshes and estuaries. They have mostly been confined to only a few elements and to saltwater or brackish systems. This study presents mass-balance results of an integrated one year campaign in a

  15. The importance of the river-estuary interface (REI) zone in estuaries

    African Journals Online (AJOL)

    drinie

    2002-07-03

    Jul 3, 2002 ... A multidisciplinary and multi-institutional research programme studied the influence of river flow rate on salinity distribution and response of the ... alia, the state of the mouth influences the extent of water exchange with the sea, vertical and ... The Kariega Estuary is a marine dominated system with very little.

  16. Distribution, vertical position and ecological implications of shallow gas in Bahía Blanca estuary (Argentina)

    Science.gov (United States)

    Bravo, M. E.; Aliotta, S.; Fiori, S.; Ginsberg, S.

    2018-03-01

    There has been a growing interest in the study of shallow gas due its importance in relation to the marine environment, climate change and human activities. In Bahía Blanca estuary, Argentina, shallow gas has a wide distribution. Acoustic turbidity and blanking are the main seismic evidence for the presence of shallow gas in the estuary. The former prevails in the inner sector of the estuary where gas is either near or in contact with the seabed. Gas deposits are generally associated with paleochannels corresponding to the Holocene paleodeltaic environment. Distribution studies of shallow gas in this estuary are necessary because its presence implies not only a geological risk for harbor activities but also because it may have noxious effects on the marine ecosystem, mainly on benthic communities. The comparison of benthic communities at a gas site (GS) with those at a control site (CS) indicated that gas could generate impoverishment in terms of individuals' abundance (GS: N = 357; CS: N = 724). Also, diversity indices showed great differences in the community structure at each site. This indicates that methane gas may act as a natural disturbance agent in estuarine ecosystems. The presence of gas in seabed sediments must therefore be taken into account when distribution studies are conducted of estuarine benthic communities.

  17. Greenhouse gas (N2O emission from Portuguese estuaries

    Directory of Open Access Journals (Sweden)

    Célia Gonçalves

    2014-07-01

    Tagus, Minho and Lima estuaries are source of N2O to the atmosphere. Particularly, in Lima estuary anthropogenic N input seems to play an important role on N2O emission. However, in a global perspective N2O attained emissions represent a reduced fraction (2O yr-1, Barnes and Upstill-Goddard, 2011. Values are comparable with those registered in some Portuguese estuaries and other European less eutrophic estuaries. However, it is known that higher N2O emissions in estuaries may occur during winter and spring (Sun et al., 2014. Thus, these systems may represent on an annual basis a larger source of N2O, which can only be clarified in future studies. Only a full comprehension of the global estuarine nitrogen cycle will provide an efficient basis of scientific knowledge for sustainably management of such ecosystems and ultimately reduce N2O emissions.

  18. Los ejemplares tipo de Cicadellinae y Gyponinae (Hemiptera: Auchenorrhyncha: Cicadellidae depositados en el Museo de La Plata, Argentina The type specimens of Cicadellinae and Gyponinae (Hemiptera: Auchenorrhyncha: Cicadellidae housed at the Museo de La Plata, Argentina

    Directory of Open Access Journals (Sweden)

    Susana L. Paradell

    2010-06-01

    Full Text Available En la presente contribución, se realizó un relevamiento de los ejemplares tipo de Cicadellidae, depositados en la colección de la División Entomología del Museo de La Plata (MLP. Fueron examinados y listados 86 ejemplares tipo pertenecientes a 32 especies: siete Cicadellinae y 25 Gyponinae, las que fueron descriptas por los siguientes autores: Berg, DeLong, DeLong & Freytag, DeLong & Martinson, Tesón, Spångberg y Young. Para cada ejemplar tipo se brinda información acerca del nombre específico, referencia bibliográfica, categoría de tipo y procedencia.

  19. Operation, Maintenance and Performance Evaluation of the Potomac Estuary Experimental Water Treatment Plant. Main Volume.

    Science.gov (United States)

    1983-09-01

    was stained with Lugol’s or D’Antonlo’s iodine stain and then examined microscopically for Giardia cysts, Entamoeba histolytica, Acanthamoeba...five-tube ..ON procedure was used for quantitating Salmonella sp . in water. The enrichmentp isolation and primary biochemical test methods are found in...8217 . . ..*- * .* . • .* .- .,,.. - ... - . .. .-. * . . . .- . ....... .. .. . . .i. . -. ’.. IO. Sampling Began I I , ta . __ _ _ _ __ _ _ _ a Grab Samples taken at 4 PM 88. I -MAR I -JUN I-SEP IDEC I-PAR I t- SP

  20. Procedimiento de los investigadores de la Universidad Nacional de La Plata en la búsqueda de información = National University of La Plata researchers procedures in information search

    Directory of Open Access Journals (Sweden)

    Silvia Albornoz

    2002-12-01

    Full Text Available La búsqueda de información y sus problemas colaterales inciden en el desarrollo de la actividad de los investigadores. Nos proponemos analizar esta temática a través del estudio de las pautas de comportamiento de investigadores de la Facultad de Humanidades y Ciencias de la Educación de la Universidad de La Plata, para identificar conductas informativas y al mismo tiempo detectar obstáculos que impiden el aprovechamiento óptimo de la Biblioteca Central y las Bibliotecas Departamentales de la Institución. Los resultados obtenidos servirán de base para definir indicadores de calidad aplicables a la mejora continua de los servicios de biblioteca. Como resultado del análisis de metodologías aplicadas en estudios de usuarios se determinó combinar las perspectivas cuantitativa y cualitativa en este trabajo en curso = The search of information and its collateral problems affect the development of the researchers activity. We would like to analyze this subject through the study of the behavior guidelines of researchers of the Faculty of Humanities and Education Sciences of the University of La Plata, in order to identify informative behavior and, at the same time, to find out the obstacles that avoid the optimal use of the Central Library and the Departmental Libraries of the Institution. The obtained results will serve as a base to define quality indicators applicable to the continuous improvement of the library services. As a result of the analysis of methodologies applied to user studies, it was decided to combine the quantitative and qualitative perspectives in this work.

  1. Procedimiento de los investigadores de la Universidad Nacional de La Plata en la búsqueda de información National University of La Plata researchers procedures in information search

    Directory of Open Access Journals (Sweden)

    Silvia Albornoz

    2002-12-01

    Full Text Available La búsqueda de información y sus problemas colaterales inciden en el desarrollo de la actividad de los investigadores. Nos proponemos analizar esta temática a través del estudio de las pautas de comportamiento de investigadores de la Facultad de Humanidades y Ciencias de la Educación de la Universidad de La Plata, para identificar conductas informativas y al mismo tiempo detectar obstáculos que impiden el aprovechamiento óptimo de la Biblioteca Central y las Bibliotecas Departamentales de la Institución. Los resultados obtenidos servirán de base para definir indicadores de calidad aplicables a la mejora continua de los servicios de biblioteca. Como resultado del análisis de metodologías aplicadas en estudios de usuarios se determinó combinar las perspectivas cuantitativa y cualitativa en este trabajo en curso.The search of information and its collateral problems affect the development of the researchers activity. We would like to analyze this subject through the study of the behavior guidelines of researchers of the Faculty of Humanities and Education Sciences of the University of La Plata, in order to identify informative behavior and, at the same time, to find out the obstacles that avoid the optimal use of the Central Library and the Departmental Libraries of the Institution. The obtained results will serve as a base to define quality indicators applicable to the continuous improvement of the library services. As a result of the analysis of methodologies applied to user studies, it was decided to combine the quantitative and qualitative perspectives in this work.

  2. Sediment accumulation rate and radiological characterisation of the sediment of Palmones River estuary (southern of Spain)

    International Nuclear Information System (INIS)

    Rubio, L.; Linares-Rueda, A.; Duenas, C.; Fernandez, M.C.; Clavero, V.; Niell, F.X.; Fernandez, J.A.

    2003-01-01

    Chemical analyses and radioecological methods were combined in order to estimate the sediment accumulation rate in the upper 20 cm depth of the Palmones River estuary. Organic matter, total carbon, C:N and 137 Cs vertical profiles showed changes at 13 cm depth. These changes could be associated with the decrease in river input since 1987 when a dam situated in the upper part of the estuary started to store water. Using 1987 as reference to date the sediment, accumulation rate was 1.2 cm yr -1 . As alternative method, two layer model of 210 Pb xs vertical distribution showed a sedimentation rate of 0.7 cm yr -1 with a surface mixing layer of 7 cm thickness. The high ammonium, potassium and sodium content in pore water and the strong correlation between 137 Cs activities and organic matter in dry sediment suggests that 137 Cs (the only anthropogenic product detected) is mainly accumulated in the estuary associated with the particulate organic material from the catchment area

  3. Sandbar Formation in the Mesjid River Estuary, Rupat Strait, Riau Province, Indonesia

    Directory of Open Access Journals (Sweden)

    Rifardi Rifardi

    2017-07-01

    Full Text Available At the aim to clarify the relationship between the sandbar  formation and lithogeneous sediment discharges, the sedimentological aspects of the Mesjid River Estuary are revealed by various analysis. The samples of bottom surface sediments and the suspended sediment were collected at 50 stations in the estuary using grab and van dorm samplers. Oceanographic observation were also carried out  at the stations. The Mesjid River Estuary receives lithogeneous sediments mainly from the Mesjid River’s drainage areas which play important role on the formation of sandbar which is shown by  a belt-like area (0.5-1.0 m depth in the area off the river mouth. The sandbar might become a sandbank in 20 to 40 years later. High suspended sediment up to 354.61 mg/l indicates the river mouth receives lithogeneous sediments. Total of 926  ton/day of the sediments supplied by the river are deposited 0.024 m/year into the area.

  4. Natural and anthropogenic hydrocarbon inputs to sediments of Patos Lagoon Estuary, Brazil.

    Science.gov (United States)

    Medeiros, Patricia Matheus; Bícego, Márcia Caruso; Castelao, Renato Menezes; Del Rosso, Clarissa; Fillmann, Gilberto; Zamboni, Ademilson Josemar

    2005-01-01

    The Patos Lagoon Estuary, southern Brazil, is an area of environmental interest not only because of tourism, but also because of the presence of the second major port of Brazil, with the related industrial and shipping activities. Thus, potential hydrocarbon pollution was examined in this study. Sediment samples were collected at 10 sites in the estuary, extracted, and analyzed by GC-FID and GC-MS for composition and concentration of the following organic geochemical markers: normal and isoprenoid alkanes, petroleum biomarkers, linear alkylbenzenes (LABs), and polycyclic aromatic hydrocarbons (PAHs). The total concentrations varied from 1.1 to 129.6 microg g(-1) for aliphatic hydrocarbons, from 17.8 to 4510.6 ng g(-1) for petroleum biomarkers, from 3.2 to 1601.9 ng g(-1) for LABs, and from 37.7 to 11,779.9 ng g(-1) for PAHs. Natural hydrocarbons were mainly derived from planktonic inputs due to a usual development of blooms in the estuary. Terrestrial plant wax compounds prevailed at sites located far from Rio Grande City and subject to stronger currents. Anthropogenic hydrocarbons are related to combustion/pyrolysis processes of fossil fuel, release of unburned oil products and domestic/industrial waste outfalls. Anthropogenic hydrocarbon inputs were more apparent at sites associated with industrial discharges (petroleum distributor and refinery), shipping activities (dry docking), and sewage outfalls (sewage). The overall concentrations of anthropogenic hydrocarbons revealed moderate to high hydrocarbon pollution in the study area.

  5. The Guayas Estuary and sea level corrections to calculate flooding areas for climate change scenarios

    Science.gov (United States)

    Moreano, H. R.; Paredes, N.

    2011-12-01

    The Guayas estuary is the inner area of the Gulf of Guayaquil, it holds a water body of around 5000 km2 and the Puna island divides the water flow in two main streams : El Morro and Estero Salado Channel (length: 90 Km.) and Jambeli and Rio Guayas Channel (length: 125km.). The geometry of the estuarine system with the behavior of the tidal wave (semidiurnal) makes tidal amplitude higher at the head than at the mouth, whereas the wave crest at the head is delayed from one and a half to two hours from that at the mouth and sea level recorded by gages along the estuary are all different because of the wave propagation and mean sea level (msl) calculated for each gage show differences with that of La Libertad which is the base line for all altitudes on land (zero level). A leveling and calculations were made to correct such differences in a way that all gages (msl) records were linked to La Libertad and this in turn allowed a better estimates of flooding areas and draw them on topographic maps where zero level corresponds to the mean sea level at La Libertad. The procedure and mathematical formulation could be applied to any estuary or coastal area and it is a useful tool to calculate such areas especially when impacts are on people or capital goods and related to climate change scenarios.

  6. XRD applied to the determination of pigments and composition of lithic materials and ceramics from archaeological pre-hispanic sites of the Rio de la Plata

    International Nuclear Information System (INIS)

    Beovide, Laura; Pardo, Helena; Faccio, Ricardo; Mombru, Alvaro; Piston, Mariela

    2011-01-01

    Full text: The earliest records of human occupation on the lower basin of Santa Lucia River are dated ca. 4800 14 C years BP, in the area of one of the major tributaries of the Rio de la Plata on the Uruguayan coast. These societies were basically hunters and gatherers until ca. 3000 14 C years BP when they incorporated the horticulture. In this multidisciplinary work, two cases of application of XRD analysis of archaeological materials are presented to provide new perspectives in solving various problems related to the technological organization of these societies. In the first case, ceramics and pigments from an archaeological context prior to the hispanic-indian contact were analyzed. The X-ray powder diffraction patterns were obtained using a RIGAKU, Ultima IV with CBO monochromator, CuK α radiation was at 40 kV and 20 mA tube power at 0.02 deg/seg, operating in the range from 2θ=5.00 to 60.00 deg. According the comparison between the experimental recorded X-ray diffraction pattern to those stored in a X-ray powder diffraction database reveals that the piece of pottery is mainly constitute of quartz (SiO 2 ) and hematite (Fe 2 O 3 ) while the mineral sample is probably composed mainly of quartz (SiO 2 ) and goethite (FeO 3 .H 2 O). The results allow a first approximation to know the inorganic pigments that were part of the decoration of the pottery and pigments used in the archaeological context. In the second case an amphibolite instrument from ca. 2700 14 C years BP related to a shell midden was analyzed and compared with amphibolites located 15 km of the archaeological site to assess if they were the raw materials for these instruments. Compositional XRD mineralogical analysis shows that the both samples seem to have similar mineral composition, which is mainly quartz (SiO 2 ) and a mixed sodium magnesium and calcium silicate (NaCa 2 (Mg 4 Ti)Si 6 Al 2 O 23 (OH) 2 ). This suggests that most likely the source of supply for the amphibolites instruments come

  7. XRD applied to the determination of pigments and composition of lithic materials and ceramics from archaeological pre-hispanic sites of the Rio de la Plata

    Energy Technology Data Exchange (ETDEWEB)

    Beovide, Laura [Department of Archeology, National Museum of Anthropology, Montevideo, (Uruguay); Pardo, Helena; Faccio, Ricardo; Mombru, Alvaro [Centro NanoMat, Polo Tecnologico de Pando, Facultad de Quimica, Universidad de la Republica, Pando, Canelones (Uruguay); Crystallography, Solid State and Materials Laboratory (Cryssmat-Lab), DETEMA, Facultad de Quimica, Universidad de la Republica, Gral, Montevideo (Uruguay); Piston, Mariela, E-mail: mpiston@fq.edu.u [Analytical Chemistry, Estrella Campos Department, Facultad de Quimica, Universidad de la Republica, Montevideo (Uruguay)

    2011-07-01

    Full text: The earliest records of human occupation on the lower basin of Santa Lucia River are dated ca. 4800 {sup 14}C years BP, in the area of one of the major tributaries of the Rio de la Plata on the Uruguayan coast. These societies were basically hunters and gatherers until ca. 3000 {sup 14}C years BP when they incorporated the horticulture. In this multidisciplinary work, two cases of application of XRD analysis of archaeological materials are presented to provide new perspectives in solving various problems related to the technological organization of these societies. In the first case, ceramics and pigments from an archaeological context prior to the hispanic-indian contact were analyzed. The X-ray powder diffraction patterns were obtained using a RIGAKU, Ultima IV with CBO monochromator, CuK{sub {alpha}} radiation was at 40 kV and 20 mA tube power at 0.02 deg/seg, operating in the range from 2{theta}=5.00 to 60.00 deg. According the comparison between the experimental recorded X-ray diffraction pattern to those stored in a X-ray powder diffraction database reveals that the piece of pottery is mainly constitute of quartz (SiO{sub 2}) and hematite (Fe{sub 2}O{sub 3}) while the mineral sample is probably composed mainly of quartz (SiO{sub 2}) and goethite (FeO{sub 3}.H{sub 2}O). The results allow a first approximation to know the inorganic pigments that were part of the decoration of the pottery and pigments used in the archaeological context. In the second case an amphibolite instrument from ca. 2700 {sup 14}C years BP related to a shell midden was analyzed and compared with amphibolites located 15 km of the archaeological site to assess if they were the raw materials for these instruments. Compositional XRD mineralogical analysis shows that the both samples seem to have similar mineral composition, which is mainly quartz (SiO{sub 2}) and a mixed sodium magnesium and calcium silicate (NaCa{sub 2}(Mg{sub 4}Ti)Si{sub 6}Al{sub 2}O{sub 23}(OH){sub 2}). This

  8. Physicochemical and biological cycles in a tide dominated, nitrogen-polluted temperate estuary

    OpenAIRE

    Wafar, M.V.M.; Le Corre, P.; Birrien, J.L.

    1988-01-01

    Spatio-temporal variations in the physicochemical and biological parameters in the Morlaix estuary on the Brittany coast of France were studied. Hydrographically, the estuary can be classified into 3 segments: the upper estuary where stratification always persists, the lower estuary where vertical homogeneity is permanent, and a middle estuary where there is a regular oscillation of stratification and homogeneity during every tidal cycle, stratification being associated with slack waters and ...

  9. Electronic tagging of green sturgeon reveals population structure and movement among estuaries

    Science.gov (United States)

    Lindley, S.T.; Erickson, D.L.; Moser, M.L.; Williams, G.; Langness, O.P.; McCovey, B.W.; Belchik, M.; Vogel, D.; Pinnix, W.; Kelly, J.T.; Heublein, J.C.; Klimley, A.P.

    2011-01-01

    Green sturgeon Acipenser medirostris spend much of their lives outside of their natal rivers, but the details of their migrations and habitat use are poorly known, which limits our understanding of how this species might be affected by human activities and habitat degradation.We tagged 355 green sturgeon with acoustic transmitters on their spawning grounds and in known nonspawning aggregation sites and examined their movement among these sites and other potentially important locations using automated data-logging hydrophones. We found that green sturgeon inhabit a number of estuarine and coastal sites over the summer, including the Columbia River estuary, Willapa Bay, Grays Harbor, and the estuaries of certain smaller rivers in Oregon, especially the Umpqua River estuary. Green sturgeon from different natal rivers exhibited different patterns of habitat use; most notably, San Francisco Bay was used only by Sacramento River fish, while the Umpqua River estuary was used mostly by fish from the Klamath and Rogue rivers. Earlier work, based on analysis of microsatellite markers, suggested that the Columbia River mixed stock was mainly composed of fish from the Sacramento River, but our results indicate that fish from the Rogue and Klamath River populations frequently use the Columbia River as well. We also found evidence for the existence of migratory contingentswithin spawning populations.Our findings have significant implications for the management of the threatened Sacramento River population of green sturgeon, which migrates to inland waters outside of California where anthropogenic impacts, including fisheries bycatch and water pollution, may be a concern. Our results also illustrate the utility of acoustic tracking to elucidate the migratory behavior of animals that are otherwise difficult to observe. ?? American Fisheries Society 2011.

  10. Sources of water column methylmercury across multiple estuaries in the Northeast U.S.

    Science.gov (United States)

    Balcom, Prentiss H; Schartup, Amina T; Mason, Robert P; Chen, Celia Y

    2015-12-20

    Estuarine water column methylmercury (MeHg) is an important driver of mercury (Hg) bioaccumulation in pelagic organisms and thus it is necessary to understand the sources and processes affecting environmental levels of MeHg. Increases in water column MeHg concentrations can ultimately be transferred to fish consumed by humans, but despite this, the sources of MeHg to the estuarine water column are still poorly understood. Here we evaluate MeHg sources across 4 estuaries and 10 sampling sites and examine the distributions and partitioning of sediment and water column MeHg across a geographic range (Maine to New Jersey). Our study sites present a gradient in the concentrations of sediment, pore water and water column Hg species. Suspended particle MeHg ranged from below detection to 187 pmol g -1 , dissolved MeHg from 0.01 to 0.68 pM, and sediment MeHg from 0.01 to 109 pmol g -1 . Across multiple estuaries, dissolved MeHg correlated with Hg species in the water column, and sediment MeHg correlated with sediment total Hg (HgT). Water column MeHg did not correlate well with sediment Hg across estuaries, indicating that sediment concentrations were not a good predictor of water MeHg concentrations. This is an unexpected finding since it has been shown that MeHg production from inorganic Hg 2+ within sediment is the primary source of MeHg to coastal waters. Additional sources of MeHg regulate water column MeHg levels in some of the shallow estuaries included in this study.

  11. Recruitment of flatfish species to an estuarine nursery habitat (Lima estuary, NW Iberian Peninsula)

    Science.gov (United States)

    Ramos, Sandra; Ré, Pedro; Bordalo, Adriano A.

    2010-11-01

    One of the present concerns of fish biologists involves defining and identifying nursery habitats in the context of conservation and resource management strategies. Fish nursery studies usually report upon nursery occupation during the latter juvenile stages, despite the fact that recruitment to nurseries can start early in life, during the larval phase. Here we investigated the use of a temperate estuarine nursery area, the Lima estuary (NW Portugal), by initial development stages of flatfish species before and after metamorphosis, integrating the larval and juvenile phases. The Lima estuarine flatfish community comprised twelve taxa, seven of which were present as pelagic larvae, six as juveniles and three as adults. There was a general trend of increasing spring-summer abundance of both larvae and juveniles, followed by a sharp winter decrease, mainly of larval flatfishes. The Lima estuary was used by Solea senegalensis, Platichthys flesus and Solea solea as a nursery area, with direct settlement for the two first species. In contrast, indirect settlement was suggested for S. solea, with metamorphosis occurring outside the estuarine area. Estuarine recruitment of S. senegalensis varied between years, with young larvae occurring in the estuary throughout a prolonged period that lasted 6-9 months, corroborating the protracted spawning season. P. flesus, the second most abundant species, exhibited a typical spring estuarine recruitment, without inter-annual variations. Developed larvae arrived in the estuary during spring, whereas the 0-group juveniles emerged in the following summer period. The present study contributes new insight to our understanding of the economically important S. senegalensis, and highlights the importance of integrating the planktonic larval phase into traditional flatfish nursery studies.

  12. Dynamics of organic and inorganic carbon in surface sediments of the Yellow River Estuary

    Science.gov (United States)

    Yu, Z.; Wang, X.; Liu, X.; Zhang, E.; Hang, F.

    2017-12-01

    Estuarine sediment is an important carbon reservoir thus may play an important role in the global carbon cycle. However, little is known on the dynamics of organic carbon (OC) and inorganic carbon (IC) in the surface sediment of the Yellow River Estuary, a large estuary in northern China. In this study, we applied element analyses and isotopic approach to study spatial distribution and sources of OC and IC in the Yellow River Estuary. We found that TIC concentration (6.3-20.1 g kg-1) was much higher than TOC (0.2-4.4 g kg-1) in the surface sediment. There showed a large spatial variability in TOC and TIC and their stable isotopes. Both TOC and TIC were higher to the north (2.6 and 14.5 g kg-1) than to the south (1.6 and 12.2 g kg-1), except in the southern bay where TOC and TIC reached 2.7 and 15.4 g kg-1, respectively. Generally, TOC and TIC in our study area was mainly autochthonous. The lower TOC values in the south section were due to relatively higher kinetic energy level whereas the higher values in the bay was attributable to terrigenous matters accumulation and lower kinetic energy level. However, the southern bay revealed the most negative δ13Corg and δ13Ccarb, suggesting that there might exist some transfer of OC to IC in the section. Our study points out that the dynamics of sedimentary carbon in the Yellow River Estuary is influenced by multiple and complex processes, and highlights the importance of carbonate in carbon sequstration.

  13. Geochemical behavior of metals and metalloids in an estuary affected by acid mine drainage (AMD).

    Science.gov (United States)

    Hierro, A; Olías, M; Ketterer, M E; Vaca, F; Borrego, J; Cánovas, C R; Bolivar, J P

    2014-02-01

    The Tinto and Odiel rivers in southwest Spain drain the world's largest sulfide mineral formation: the Iberian Pyrite Belt which has been worked since 2,500 BC. The Tinto and Odiel estuarine zones include both an extensive area of salt marsh and an intensively industrialized urban area. As a consequence of pyrite oxidation, the Tinto and Odiel rivers are strongly acidic (pH major and trace elements were determined in the acid mine drainage affected estuary of the Ría de Huelva. During estuarine mixing, ore-derived metal concentrations exhibit excellent correlations with pH as the main controlling parameter. As pH increases, concentrations of dissolved ore-associated elements are attenuated, and this process is enhanced during the summer months. The decrease in Fe and Al concentrations ranged from 80 to 100 % as these elements are converted from dissolved to sediment-associated forms in the estuary. Coprecipitation/adsorption processes also removed between 60 and 90 % of the originally dissolved Co, Cu, Mn, Pb, Zn, and Th; however, Cd and Ni exhibited a greater propensity to remain in solution, with an average removal of approximately 60 %. On the other hand, As and U exhibited a different behavior; it is likely that these elements remain in dissolved forms because of the formation of U carbonates and soluble As species. Concentrations of As remain at elevated levels in the outer estuary (average = 48 μg L(-1)) which exceeds concentrations present in the Tinto River. Nevertheless, the estuary has recently witnessed improvements in water quality, as compared to results of several previous studies reported in the 1990s.

  14. Historical economic and environmental policies influencing trace metal inputs in Montevideo Bay, Río de la Plata.

    Science.gov (United States)

    Bueno, C; Brugnoli, E; Figueira, R C L; Muniz, P; Ferreira, P A L; García Rodríguez, F

    2016-12-15

    Montevideo Bay is located in the middle zone of the Rio de la Plata, and since the foundation of the city, several key economic and environmental policies affected the industry, and thus, metal inputs into this ecosystem. The aim of this study is to evaluate the sedimentary geochemical record of Montevideo Bay, in order to determine the historical inputs of anthropogenic metals to the system. In addition, environmental and economic policies of the country were taken into account to infer the relationship between them and the historic metal input. Concentrations of aluminum, chromium, copper, lead, scandium and zinc were analyzed and the EF and SPI indices were calculated. The analysis showed that since Montevideo foundation, metal concentrations increased in accordance with industry development, and the indices as well as the metal concentration represent a reliable footprint of the history of different economic and environmental policies influencing historical industrial activities. Copyright © 2016 Elsevier Ltd. All rights reserved.

  15. Los ejemplares tipo de Cicadellinae y Gyponinae (Hemiptera: Auchenorrhyncha: Cicadellidae depositados en el Museo de La Plata, Argentina

    Directory of Open Access Journals (Sweden)

    Susana L. PARADELL

    2010-01-01

    Full Text Available En la presente contribución, se realizó un relevamiento de los ejemplares tipo de Cicadellidae, depositados en la colección de la División Entomología del Museo de La Plata (MLP. Fueron examinados y listados 86 ejemplares tipo pertenecientes a 32 especies: siete Cicadellinae y 25 Gyponinae, las que fueron descriptas por los siguientes autores: Berg, DeLong, DeLong & Freytag, DeLong & Martinson, Spångberg , Tesón y Young. Para cada ejemplar tipo se brinda información acerca del nombre específico, referencia bibliográfica, categoría de tipo y procedencia.

  16. Study of sediment behaviour in Rio de la Plata, Punta Carmelo area with use of radioactive trace

    International Nuclear Information System (INIS)

    Vianna Bandeira, J.; Godinho Pinto, G.; Suarez Antola, R.

    1998-01-01

    This work is related to the sedimentological studies with the application of radioactive tracers, carried out in the region of Puerto Carmelo, Rio de la Plata-Uruguay, under the Tc Project of the International Atomic Energy Agency (IAEA) URU/8/009, with the objective of evaluating the bed load transport of sand, in the region where a new access channel to the harbour of Carmelo, was designed. These studies, performed together hydraulic measurements, were important for the comprehension of the behaviour of the sediment transportation under the action of the hydrodynamic agents (currents and waves); the determination of the bed load rate and its application to the evaluation of the maintenance dredging, the definition of the optimum path for the access channel, based on the deposition process of the injected tracer, 30 cm above the bottom. The maximum accretion rate is for the designed channel is around 11000 m3/year. (author)

  17. Aborto, abandono, y la muerte de Augusta García Platas en Ayacucho, Perú, 1946

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    Raúl Necochea López

    Full Text Available Resumen Augusta García Platas murió tras un aborto clandestino en Ayacucho en 1946. Este ensayo, basado en materiales del Archivo Histórico de Ayacucho, da cuenta del proceso criminal que se abrió para determinar los responsables de su muerte. A pesar de que sindicaron a ciertos individuos como culpables directos de provocar el aborto, las autoridades judiciales consideraban que la causa de fondo de la muerte de la joven había sido el abandono por parte de quienes debían velar por su salud física y moral. Este caso nos brinda la oportunidad de esclarecer las estrategias que los implicados usaban para defenderse de acusaciones criminales. Además, nos ayuda a entender las diversas deficiencias del Poder Judicial peruano de mediados del siglo XX.

  18. Compte rendu de la 18e Conférence Internationale sur le Tournesol : Mar del Plata & Balcarce (Argentine, 2012

    Directory of Open Access Journals (Sweden)

    Pilorgé Étienne

    2012-11-01

    Full Text Available The 18th International Sunflower Conference took place in Mar del Plata, Argentina, in February, 2012. The key-points and evolutions of sunflower research were presented, in the fields of agronomy, physiology, genetics and genomics, crop protection, quality and markets. Major evolutions can be observed concerning the sequencing of sunflower genome, announced to be complete by the end of 2012, but also concerning the use of models and the progress in the studies on the interactions between varieties genetic pattern, environment and crop management practices. In crop protection aspects, the evolutions of the major pathogens, downy mildew and Orobanche cumana, have been discussed, as well as the breeding efforts for genetic resistances, or the advances concerning the herbicides tolerant varieties. Evolutions in oil quality aspects have been exposed too, such as varieties enriched in stearic acid, or tocopherols, or with low contents in saturated fatty acids.

  19. As exposições e seus publicos : a paleontologia no Museo de La Plata (Provincia de Buenos Aires, Argentina)

    OpenAIRE

    Sandra Elena Murriello

    2006-01-01

    Resumo: Esta tese pretende ser uma contribução à compreensão do diálogo estabelecido nas instituições museais com seus múltiplos visitantes, o que vem permitindo a sobrevivência, quando não a transformação, e consolidação dos museus como espaços culturais valorizados socialmente. Em particular, analiso a relação estabelecida entre o público do Museo de La Plata (Província de Buenos Aires, Argentina) e suas exposições paleontológicas. Essas exposições e suas valiosas coleções são as mais procu...

  20. The job market and temporary work programs. ANalysis of the case of the Greater La Plata conglomerate 2003-2008

    Directory of Open Access Journals (Sweden)

    Juliana Santa María

    2009-01-01

    Full Text Available This paper aims at looking into the job market situation in the Greater La Plata conglomerate, focusing its attention on the implementation of Temporary Work Programs as a clearly passive tool used by the State -especially during the last few decades- to deal with the population's employment issues. Based on the situation that the region presents, the specific situation of the municipality of Berisso which is part of the conglomerate will be looked into, in order to carry out an in-depth analysis of these types of policies' effective implementation forms and strategies on the municipal level. The Permanent Home Survey (EHP - INDEC, information provided by the Municipality and documents on Employment Policies and Programs will be used in order to complete this work.

  1. Otras voces de la Edad de Plata: Francisco Valdés, escritor y crítico literario

    Directory of Open Access Journals (Sweden)

    Guadalupe Nieto Caballero

    2017-02-01

    Full Text Available El artículo estudia la prosa ensayística y aforística de Francisco Valdés, autor extremeño protagonista de la Edad de Plata. En sus textos, Valdés desarrolla una crítica que parte de la perspectiva de un lector atento, llegando a proponer, incluso, reinterpretaciones de las obras que glosa. De sus artículos en prensa se analizan su estilo y los autores que comenta, fuente indiscutible para conocer sus referentes y los caminos de su prosa. Se analizarán también algunos aspectos de su producción aforística a partir de un cuaderno inédito que enlaza perfectamente con la línea de la literatura de la época. 

  2. Labor conflict, general strikes and dynamics of trade union organizations in the Gran La Plata 1969-1972

    Directory of Open Access Journals (Sweden)

    Agustín Nava

    2017-07-01

    Full Text Available This paper is inscribed within studies on the history of the labor movement during the years '60 and '70 in Argentina and aims to analyze the cycle of general strikes and labor conflictivity that took place more specifically between the years 1969-1972 on a particular region: the Gran La Plata. Through a qualitative and quantitative analysis we will approach the dynamics of general strikes and their impact on our study region, as a kind of struggle that allows us to analyze the different tendencies and forms assumed by the conflict, the degrees of unity within the labor movement, the dynamics of trade unions, alliances with other social forces and the relationship with the state. Therefore, this article contributes to study not only certain specific dynamics of labor conflictivity in our study region, but also the more general cycle of social protest and political radicalization that took place in Argentina during the sixties and seventies

  3. Environmental Flow for Sungai Johor Estuary

    Science.gov (United States)

    Adilah, A. Kadir; Zulkifli, Yusop; Zainura, Z. Noor; Bakhiah, Baharim N.

    2018-03-01

    Sungai Johor estuary is a vital water body in the south of Johor and greatly affects the water quality in the Johor Straits. In the development of the hydrodynamic and water quality models for Sungai Johor estuary, the Environmental Fluid Dynamics Code (EFDC) model was selected. In this application, the EFDC hydrodynamic model was configured to simulate time varying surface elevation, velocity, salinity, and water temperature. The EFDC water quality model was configured to simulate dissolved oxygen (DO), dissolved organic carbon (DOC), chemical oxygen demand (COD), ammoniacal nitrogen (NH3-N), nitrate nitrogen (NO3-N), phosphate (PO4), and Chlorophyll a. The hydrodynamic and water quality model calibration was performed utilizing a set of site specific data acquired in January 2008. The simulated water temperature, salinity and DO showed good and fairly good agreement with observations. The calculated correlation coefficients between computed and observed temperature and salinity were lower compared with the water level. Sensitivity analysis was performed on hydrodynamic and water quality models input parameters to quantify their impact on modeling results such as water surface elevation, salinity and dissolved oxygen concentration. It is anticipated and recommended that the development of this model be continued to synthesize additional field data into the modeling process.

  4. Scavenging rate ecoassay: a potential indicator of estuary condition.

    Science.gov (United States)

    Porter, Augustine G; Scanes, Peter R

    2015-01-01

    Monitoring of estuary condition is essential due to the highly productive and often intensely impacted nature of these ecosystems. Assessment of the physico-chemical condition of estuaries is expensive and difficult due to naturally fluctuating water quality and biota. Assessing the vigour of ecosystem processes is an alternative method with potential to overcome much of the variability associated with physico-chemical measures. Indicators of estuary condition should have small spatial and temporal variability, have a predictable response to perturbation and be ecologically relevant. Here, we present tests of the first criterion, the spatio-temporal variability of a potential ecoassay measuring the rate of scavenging in estuaries. We hypothesised that the proposed scavenging ecoassay would not vary significantly among A) sites in an estuary, B) trips separated by weeks, or C) days in a trip. Because not all habitats are present in all estuaries, this test was undertaken in two habitats. When conducted over bare substrate there were occasional significant differences, but no discernible patterns, within levels of the experiment. When conducted over vegetated substrate, days within a trip did not vary significantly, but later trips experienced greater scavenging. This scavenging ecoassay shows potential as a tool for assessing the condition of estuarine ecosystems, and further exploration of this protocol is warranted by implementation in estuaries across a gradient of anthropogenic stress.

  5. Cyanobacteria and macroalgae in ecosystem of the Neva estuary

    Directory of Open Access Journals (Sweden)

    Nikulina V. N.

    2011-07-01

    Full Text Available The Baltic Sea and Neva estuary are plagued by coastal eutrophication. In order to estimate the scale of the problem, quantitative estimates of phytoplankton and macroalgal mats were determined in the Neva estuary. Long-term monitoring (1982–2009 of phytoplankton showed changes in its species composition and abundance. Summer phytoplankton biomass increased significantly in the 1990s, with concomitant changes in species composition, despite a decline of nutrients in the Neva estuary. The cyanobacteria Planktothrix agardhii became a dominant species. The summer biomass of phytoplankton reached a maximum of 5.2 ± 0.4 mg·L-1 in 2002–2004. Monitoring of macroalgal community in the coastal area of the Neva estuary from 2002 to 2009 showed the dominance of the filamentous green alga Cladophora glomerata in the phytobenthos. Average biomass of macroalgae in inner and outer estuary differed significantly at 132 ± 29 and 310 ± 67 g DW·m-2, respectively. This study showed, that fluctuations in macroalgal biomass reflected human influence on estuary, although it was less sensitive to human impact than the phytoplankton community. Thus qualitative and quantitative characteristics of phytoplankton and macroalgal blooms can indicate anthropogenic influence on the ecosystem, and help to better manage the Neva estuary.

  6. On the use of MODIS and TRMM products to simulate hydrological processes in the La Plata Basin

    Science.gov (United States)

    Saavedra Valeriano, O. C.; Koike, T.; Berbery, E. H.

    2009-12-01

    La Plata basin is targeted to establish a distributed water-energy balance model using NASA and JAXA satellite products to estimate fluxes like the river discharge at sub-basin scales. The coupled model is called the Water and Energy Budget-based Distributed Hydrological Model (WEB-DHM), already tested with success in the Little Washita basin, Oklahoma, and the upper Tone River in Japan. The model demonstrated the ability to reproduce point-scale energy fluxes, CO2 flux, and river discharges. Moreover, the model showed the ability to predict the basin-scale surface soil moisture evolution in a spatially distributed fashion. In the context of the La Plata Basin, the first step was to set-up the water balance component of the distributed hydrological model of the entire basin using available global geographical data sets. The geomorphology of the basin was extracted using 1-km DEM resolution (obtained from EROS, Hydro 1K). The total delineated watershed reached 3.246 millions km2, identifying 145 sub-basins with a computing grid of 10-km. The distribution of land cover, land surface temperature, LAI and FPAR were obtained from MODIS products. In a first instance, the model was forced by gridded rainfall from the Climate Prediction Center (derived from available rain gauges) and satellite precipitation from TRMM 3B42 (NASA & JAXA). The simulated river discharge using both sources of data was compared and the overall low flow and normal peaks were identified. It was found that the extreme peaks tend to be overestimated when using TRMM 3B42. However, TRMM data allows tracking rainfall patterns which might be missed by the sparse distribution of rain gauges over some areas of the basin.

  7. REDESCRIPCIÓN DE POTAMOLITHUS SUPERSULCATUS PILSBRY, 1896 (GASTROPODA, TATEIDAE DEL SUR DE LA CUENCA DEL PLATA

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    MICAELA DE LUCÍA

    Full Text Available RESUMEN El género Potamolithus Pilsbry, 1896 (Gastropoda; Tateidae, posee 31 especies, 22 de las cuales se hayan en la Argentina distribuidas principalmente en la cuenca Del Plata, definiendo al río Uruguay y al Río de la Plata como una zona caliente de diversidad en gasterópodos dulceacuícolas. Sin embargo, la mayoría de sus especies han sido descriptas solo por caracteres conquilógicos y, unas pocas tienen datos anatómicos, conllevando a la descripción de subespecies o morfos que se superponen unos a otros. A Potamolithus lapidum algunos autores le atribuyen cuatro subespecies (con datos conquiológicos, y una con datos parciales de anatomía blanda, sin embargo otros incluyen ocho “morfos”. Aquí nosotros damos un comienzo en el estudio de Potamolithus lapidum elevando a Potamolithus lapidum supersulcatus Pilsbry, 1896 a la categoría de especie, de la cual solo se conocen caracteres conquiológicos y radulares parcialmente. Aportamos datos de: concha, órganos paleales, cabeza, pie, pene, rádula, sistemas reproductor femenino y masculino, sistema nervioso y, secuencia parcial del gen mitocondrial citocromo c oxidasa subunidad I. Es necesario realizar una buena descripción de las especies del género Potamolithus debido a que algunas de las especies ya han sido citadas como especies vulnerables y que habitan ríos que están siendo modificados por la actividad humana y por la presencia del bivalvo invasor Limnoperna fortunei.

  8. La ciudad y la corte como espacios de poder en Hispanoamérica. La plata colonial

    Directory of Open Access Journals (Sweden)

    Bridikhina, Eugenia

    2007-08-01

    Full Text Available This article demostrates how the City of La Plata, headquarters of the Audiencia and the Archbishopric, became defined as the Provincial Court, the centre of courtesan life, and the ceremonial centre of the monarchy. Public ceremonies and etiquette served as an instrument for royal domination represented in the social hierarchy, which defined and limited the social mobility of protagonists in colonial society. Ruling class acceptance of norms of conduct identical to Royal Court, and a similar social hierarchy with similar norms allowed for the functioning of the competitive and antagonistic worlds of Charca´s society.

    Este artículo pretende demostrar que la ciudad de La Plata, sede de la Audiencia y Arzobispado se definió como la Corte provincial, el centro de vida cortesana y el escenario ceremonial de la monarquía. Las ceremonias públicas y etiquetas que se realizaban en este espacio del poder servían como un instrumento de dominio real, representaban y reforzaban la jerarquía social, marcando el lugar que sus protagonistas tenían en sociedad colonial. La aceptación por las clases dirigentes de pautas de conducta y sociabilidad idénticas a los de la Corte Real, y de un modelo similar de diferenciación jerárquica, con sus normas y reglas hacía que funcionara el mundo competitivo y antagónico de la sociedad charqueña.

  9. Creating diverse wildlife habitat at La Plata mine, Northwestern New Mexico, a case study: part 2. soils and vegetation

    Energy Technology Data Exchange (ETDEWEB)

    Musslewhite, B.D.; Buchanan, B.A.; Ramsey, T.C.; Hamilton, J.S.; Luther, J. [Buchanan Consultants Ltd., Farmington, NM (United States)

    2001-07-01

    Biodiversity has increasingly become an important issue in determining the success of reclaimed minelands. The post-mine land-use of La Plata Mine is wildlife habitat, primarily for ungulates and small mammals. A reclamation plan was developed to promote biodiversity of reclaimed lands through the use of variable soil substrates, landscape features, and targeted seed mixes. A GIS was used to delineate the post-mine final surface contour into eight slope classes and eight aspect classes. The class information was used to develop four reclamation land types: 1. Upland shrub - north aspects, 2. Upland shrub - south aspects, 3. Grassland, and 4. Drainage. These land types correspond to four reclamation vegetation types. Suitable spoil materials and coarse textured topsoil materials were targeted for use on strongly sloping areas to minimize soil loss. Finer textured topsoil materials were targeted for the grassland and drainage types. The replacement depth of topsoil and topsoil substitute materials was varied for the reclamation vegetation types. Pre-mine vegetation inventories were used to develop unique seed mixes specific to physical habitat conditions exhibited by each land-type. Research conducted at La Plata Mine found that topsoil replacement thickness less than 15 cm promotes shrub establishment and topsoil thickness greater than 30 cm promotes native grass species. Therefore, areas designated for shrub communities will receive an average of 10 cm of topsoil or topsoil substitute material and the areas designated for grassland and drainage type communities will receive a minimum of 40 cm of topsoil. 12 refs., 1 fig., 1 tab.

  10. Fishes and fisheries in tropical estuaries: The last 10 years

    Science.gov (United States)

    Blaber, S. J. M.

    2013-12-01

    Since 2002 there has been an increase in knowledge of many aspects of the biology and ecology of tropical estuarine fishes, as well as significant changes to many estuarine fisheries. Analyses of literature databases (2002-2012) show that: of the c. 600 relevant papers, 52% are primarily related to ecology, 11% to conservation, 11% to anthropogenic and pollution effects on fishes, 9% to fisheries, 7% to aquaculture, 4% to study techniques, and 1% each to fish larvae, effects of fishing, taxonomy, climate change, evolution and genetics. In terms of geographic spread 17% are from North America, 15% from south Asia, 14% from the Caribbean, 13% from Australasia, 12% from Africa and 9% each from South America and SE Asia. Research papers came from 50 countries of which the dominant were USA (15%), India (12%), Australia (11%) and Brazil (7%). Increasing numbers of studies in West Africa, SE and South Asia and South America have increased basic knowledge of the ecology of estuarine fish faunas. Increases in understanding relate to: roles of salinity, turbidity and habitat diversity; connectivity between habitats; water flow; ecological drivers of spatial variability; scale dependent variation; thermal tolerances; movement patterns; food webs; larval adaptations; and the viability of areas heavily impacted by human activities. New reviews both challenge and support different aspects of the estuarine dependence paradigm - still perhaps one of the main research issues - and the protective function of estuaries and mangroves for juvenile fishes has received attention in relation to e.g. predation risks and fisheries. There have also been significant advances in the use of guilds and biodiversity models. Fishing pressures have continued unabated in most tropical estuaries and are summarised and management issues discussed. Understanding of the relationships between fisheries production and mangroves has advanced and significant differences have emerged between Indo

  11. Variability in warm-season atmospheric circulation and precipitation patterns over subtropical South America: relationships between the South Atlantic convergence zone and large-scale organized convection over the La Plata basin

    Science.gov (United States)

    Mattingly, Kyle S.; Mote, Thomas L.

    2017-01-01

    Warm-season precipitation variability over subtropical South America is characterized by an inverse relationship between the South Atlantic convergence zone (SACZ) and precipitation over the central and western La Plata basin of southeastern South America. This study extends the analysis of this "South American Seesaw" precipitation dipole to relationships between the SACZ and large, long-lived mesoscale convective systems (LLCSs) over the La Plata basin. By classifying SACZ events into distinct continental and oceanic categories and building a logistic regression model that relates LLCS activity across the region to continental and oceanic SACZ precipitation, a detailed account of spatial variability in the out-of-phase coupling between the SACZ and large-scale organized convection over the La Plata basin is provided. Enhanced precipitation in the continental SACZ is found to result in increased LLCS activity over northern, northeastern, and western sections of the La Plata basin, in association with poleward atmospheric moisture flux from the Amazon basin toward these regions, and a decrease in the probability of LLCS occurrence over the southeastern La Plata basin. Increased oceanic SACZ precipitation, however, was strongly related to reduced atmospheric moisture and decreased probability of LLCS occurrence over nearly the entire La Plata basin. These results suggest that continental SACZ activity and large-scale organized convection over the northern and eastern sections of the La Plata basin are closely tied to atmospheric moisture transport from the Amazon basin, while the warm coastal Brazil Current may also play an important role as an evaporative moisture source for LLCSs over the central and western La Plata basin.

  12. Polycyclic aromatic hydrocarbons (PAHs) in a large South American industrial coastal area (Santos Estuary, Southeastern Brazil): Sources and depositional history

    International Nuclear Information System (INIS)

    Martins, Cesar C.; Bicego, Marcia C.; Mahiques, Michel M.; Figueira, Rubens C.L.; Tessler, Moyses G.; Montone, Rosalinda C.

    2011-01-01

    Highlights: → In early 1980s, Santos Estuary became known as one of the worst polluted in the world. → PAHs levels were similar to the values reported for marine sediments worldwide. → PAHs analyses indicated multiple sources of these compounds (oil and pyrolitic origin). → The decline of oil consumption due to the world oil crisis (late 1970s) was shown. → The input of organic pollutants is a historical problem for the Santos Estuary. - Abstract: Located in southeastern Brazil, the Santos Estuary has the most important industrial and urban population area of South America. Since the 1950's, increased urbanization and industrialization near the estuary margins has caused the degradation of mangroves and has increased the discharge of sewage and industrial effluents. The main objectives of this work were to determine the concentrations and sources of polycyclic aromatic hydrocarbons (PAHs) in sediment cores in order to investigate the input of these substances in the last 50 years. The PAHs analyses indicated multiple sources of these compounds (oil and pyrolitic origin), basically anthropogenic contributions from biomass, coal and fossil fuels combustion. The distribution of PAHs in the cores was associated with the formation and development of Cubatao industrial complex and the Santos harbour, waste disposal, world oil crisis and the pollution control program, which results in the decrease of organic pollutants input in this area.

  13. Effect of water flux and sediment discharge of the Yangtze River on PAHs sedimentation in the estuary.

    Science.gov (United States)

    Li, Rufeng; Feng, Chenghong; Wang, Dongxin; He, Maozhi; Hu, Lijuan; Shen, Zhenyao

    2016-12-01

    Historical distribution characteristics of polycyclic aromatic hydrocarbons (PAHs) and their carriers (i.e., organic matter and mineral particles) in the sediment cores of the Yangtze Estuary were investigated, with emphasis laid on the role of the Yangtze River. Grain size component of sediments (clay, silt, and sand) and organic carbon (black carbon and total organic carbon) in the sediment cores were markedly affected by water flux and sediment discharge of the Yangtze River. Qualitative and quantitative analysis results showed that sands and black carbon acted as the main carriers of PAHs. The sedimentation of two-ring to three-ring PAHs in the estuary had significant correlations with water flux and sediment discharge of the Yangtze River. The relative lower level of the four-ring and five-ring to six-ring PAHs concentrations appeared around the year 2003 and remained for the following several years. This time period accorded well with the water impoundment time of the Three Gorges Reservoir. The decreased level of two-ring to three-ring PAHs occurred in the year 1994, and the peak points around the year 2009 indicated that PAHs sedimentation in the estuary also had close relationship to severe drought and flood in the catchments. The findings presented in this paper could provide references for assessing the impacts of water flux and sediment discharge on the historical deposition of PAHs and their carriers in the Yangtze Estuary.

  14. Sources and distribution of aromatic hydrocarbons in a tropical marine protected area estuary under influence of sugarcane cultivation.

    Science.gov (United States)

    Arruda-Santos, Roxanny Helen de; Schettini, Carlos Augusto França; Yogui, Gilvan Takeshi; Maciel, Daniele Claudino; Zanardi-Lamardo, Eliete

    2018-05-15

    Goiana estuary is a well preserved marine protected area (MPA) located on the northeastern coast of Brazil. Despite its current state, human activities in the watershed represent a potential threat to long term local preservation. Dissolved/dispersed aromatic hydrocarbons and polycyclic aromatic hydrocarbons (PAHs) were investigated in water and sediments across the estuarine salt gradient. Concentration of aromatic hydrocarbons was low in all samples. According to results, aromatic hydrocarbons are associated to suspended particulate matter (SPM) carried to the estuary by river waters. An estuarine turbidity maximum (ETM) was identified in the upper estuary, indicating that both sediments and contaminants are trapped prior to an occasional export to the adjacent sea. PAHs distribution in sediments were associated with organic matter and mud content. Diagnostic ratios indicated pyrolytic processes as the main local source of PAHs that are probably associated with sugarcane burning and combustion engines. Low PAH concentrations probably do not cause adverse biological effects to the local biota although their presence indicate anthropogenic contamination and pressure on the Goiana estuary MPA. Copyright © 2017 Elsevier B.V. All rights reserved.

  15. Waterfowl migration and distribution in North West estuaries. V. 1

    International Nuclear Information System (INIS)

    Clark, N.A.; Kirby, J.S.; Langston, R.H.W.; Donald, P.; Mawdesley, T.; Evans, J.

    1990-12-01

    Waterfowl populations may be affected by proposed tidal barrage across the Mersey. This study had three objectives:-(1) to evaluate the patterns of usage of the intertidal flats of the Mersey estuary by waders and wildfowl and to establish which are the preferred areas; (2) to identify the places of origin and movement patterns of the populations of waders and wildfowl that visit the Mersey Estuary; and (3) to evaluate evidence regarding the capacity of British estuaries to absorb waders and wildfowl populations which might be displaced by a Mersey Barrage. The text and tables and results only are presented in Volume 1. (author)

  16. Main Memory DBMS

    NARCIS (Netherlands)

    P.A. Boncz (Peter); L. Liu (Lei); M. Tamer Özsu

    2008-01-01

    htmlabstractA main memory database system is a DBMS that primarily relies on main memory for computer data storage. In contrast, normal database management systems employ hard disk based persisntent storage.

  17. Salt Intrusion in the Tweed Estuary

    Science.gov (United States)

    Uncles, R. J.; Stephens, J. A.

    1996-09-01

    Results are presented from a 2-week field programme in the Tweed Estuary, U.K. Maximum values of the empirically based Estuarine Richardson Number, Ri E, occurred during neap tides, and minimum values occurred during spring tides. Estimated values of Ri Evaried between 0·3 and 2·3, suggesting the occurrence of partially mixed to stratified conditions, depending on tidal state and freshwater inflow. These relatively large values of Ri Ewere consistent with both observed strong salinity stratification and large salt fluxes due to vertical shear transport. Low values (0·5) values in the halocline. A velocity maximum occurred within the halocline during the early flood. Wave-like spatial oscillations of the halocline occurred on the ebb. The oscillation troughs were situated above deep holes located just down-estuary of the rail and old road bridges. There was an indication that the constricted flow between the bridges' arches resulted in enhanced mixing of near-surface waters and a thickening of the halocline. It is also possible that these wave-like structures were stationary, near-critical internal lee waves, triggered by the deep holes. Trapping of high-salinity waters occurred on the ebb. Saline pools were isolated within a deep hole or deeper section of bed by the falling halocline. When the salt wedge moved further down-estuary, the ' trapped ' waters were subjected to strongly ebbing, overlying freshwater, and were subsequently entrained and flushed. The salinity intrusion was a strong function of spring-neap tidal state and a weaker function of freshwater inflow. The estimated salinity intrusion varied from about 4·7 to 7·6 km during the fieldwork period. The strong dependence on tidal range followed from the comparable lengths of the tidal excursion and salinity intrusion. Long excursion lengths were also partly responsible for the short residence (or flushing) times and their strong dependence on spring-neap tidal state. For typical summer freshwater

  18. Solar radiation and its penetration in a tropical estuary

    Digital Repository Service at National Institute of Oceanography (India)

    Qasim, S.Z.; Bhattathiri, P.M.A.; Abidi, S.A.H.

    The Cochin Backwater which is an estuarine area on the west coast of India receives maximum solar radiation from December to March and minimum from June to September. During the monsoon months the estuary becomes highly turbid as a result...

  19. Evaluating Causes of Ecological Impairments in the Estuaries of Ukraine

    Science.gov (United States)

    Ukrainian estuaries have not undergone a systematic evaluation of the causes of ecological impairments caused by anthropogenic contamination. The objective of this evaluation is to use recently developed diagnostic tools to determine the causes of benthic ecological impairments. ...

  20. Fish and Salinity in the San Francisco Estuary

    Science.gov (United States)

    This page provides access to a set of time-series maps for six fishes that live in the SF Estuary. Maps were produced to strengthen best available science that inform actions needed to improve protection for aquatic life.

  1. Estuary 2100 Project, Phase 2: Building Partnerships for Resilient Watersheds

    Science.gov (United States)

    Information about the SFBWQP Estuary 2100 Project, Phase 2: Building Partnerships for Resilient Watersheds, part of an EPA competitive grant program to improve SF Bay water quality focused on restoring impaired waters and enhancing aquat

  2. an ecophysiological study of the meiofauna of the swartkops estuary ...

    African Journals Online (AJOL)

    fauna in two exposed beaches in the Swartkops Estuary, near Port Elizabeth, were elucidated. PopUlation ... Variations of temperature and oxygen were found to be responsible for this pattern. ..... Apart from very low numbers of hermit crabs.

  3. Plutonium in Atlantic coastal estuaries in the southeastern United States

    International Nuclear Information System (INIS)

    Hayes, D.W.; LeRoy, J.H.; Cross, F.A.

    1975-01-01

    A survey was made to begin to provide baseline information on the Pu distribution of representative estuarine and coastal areas of the southeastern United States. Sediments and marsh grass (Spartina) were collected and analyzed from three locations within a tidal marsh. In three estuaries (Savannah, Neuse, and Newport), the suspended particulate matter (1 μm and greater) was filtered from waters with different salinities, and the plutonium content of the particulates determined. The Savannah River estuary, in addition to fallout Pu, has received up to 0.3 Ci of Pu from the Savannah River Plant (SRP) of the U. S. Energy Research and Development Administration. The SRP plutonium has a variable isotopic composition that can influence Pu isotopic ratios in the estuarine system. The other estuaries do not have nuclear installations upstream. Data are included on the content of 238 Pu, 239 Pu, and 240 Pu in sediments and marsh grass of the Savannah River estuary

  4. St. Louis River Estuary 2011 - 2013 Faucet snail location data

    Data.gov (United States)

    U.S. Environmental Protection Agency — The dataset consists of GPS coordinates for benthic invertebrate collections made in the St. Louis River Estuary in 2011 through 2013, and information on whether and...

  5. Heavy metal accumulation in a flow restricted, tropical estuary

    Digital Repository Service at National Institute of Oceanography (India)

    Balachandran, K.K.; Laluraj, C.M.; Nair, M.; Joseph, T.; Sheeba, P.; Venugopal, P.

    Levels of heavy metals (Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb and Zn), organic carbon content and textural characteristics in the surficial sediments of Cochin estuary (SW coast of India) and adjacent coast are presented. Anthropogenic inputs from...

  6. Comparative assessment of two agriculturally-influenced estuaries

    CSIR Research Space (South Africa)

    Lemley, DA

    2017-04-01

    Full Text Available This study compared the spatio-temporal dynamics in two agriculturally-influenced South African estuaries - Gamtoos and Sundays - to investigate how contrasting hydrological alterations influence physical, chemical and biological responses...

  7. Bacterial contamination of mussels at Mahe estuary, Malabar coast

    Digital Repository Service at National Institute of Oceanography (India)

    Gore, P.S.; Raveendran, O.; Iyer, T.S.G.; Varma, P.R.G.; Sankaranarayanan, V.N.

    Mussel samples from the mussel bed and near-by market, beach sand, sediment and water from the Mahe Estuary, Kerala, India were analysed for the bacterial quality. Indicator bacteria such as Escherichia coli and faecal streptococci were isolated...

  8. Habitat Scale Mapping of Fisheries Ecosystem Service Values in Estuaries

    Directory of Open Access Journals (Sweden)

    Timothy G. O'Higgins

    2010-12-01

    Full Text Available Little is known about the variability of ecosystem service values at spatial scales most relevant to local decision makers. Competing definitions of ecosystem services, the paucity of ecological and economic information, and the lack of standardization in methodology are major obstacles to applying the ecosystem-services approach at the estuary scale. We present a standardized method that combines habitat maps and habitat-faunal associations to estimate ecosystem service values for recreational and commercial fisheries in estuaries. Three case studies in estuaries on the U.S. west coast (Yaquina Bay, Oregon, east coast (Lagoon Pond, Massachusetts, and the Gulf of Mexico (Weeks Bay, Alabama are presented to illustrate our method's rigor and limitations using available data. The resulting spatially explicit maps of fisheries ecosystem service values show within and between estuary variations in the value of estuarine habitat types that can be used to make better informed resource-management decisions.

  9. How the National Estuary Programs Address Environmental Issues

    Science.gov (United States)

    Estuaries face many challenges including, alteration of natural hydrologic flows, aquatic nuisance species, climate change, declines in fish and wildlife populations, habitat loss and degradation, nutrient loads, pathogens, stormwater and toxics.

  10. Short term variations in particulate matter in Mahi river estuary

    Digital Repository Service at National Institute of Oceanography (India)

    Bhosle, N.B.; Rokade, M.A.; Zingde, M.D.

    The particulate matter (PM) collected from Mahi River Estuary was analysed for organic carbon (POC), nitrogen (PON), and chlorophyll a (Chl a). The concentration of PM, POC, PON and Chl a showed short term variations. Average surface concentration...

  11. Time-dependence of salinity in monsoonal estuaries

    Digital Repository Service at National Institute of Oceanography (India)

    Vijith, V.; Sundar, D.; Shetye, S.R.

    processes (diffusion, gravity current formation, impact of tidal asymmetries, etc.) is balanced by salinity-egress induced by runoff. Here we point out that the salinity field of the estuaries that are located on the coasts of the Indian subcontinent...

  12. Phytoplankton Diversity in the Cross River Estuary of Nigeria ...

    African Journals Online (AJOL)

    DR. MIKE HORSFALL

    This study was carried out to provide a concise set of structural based .... further growth of diatom in this zone due to rapid uptake of ... Table 1: Taxonomic listing and spatial distribution of phytoplankton species in Cross Rivers estuary. (+ =.

  13. Commercially important penaeid shrimp larvae in the estuaries of Goa

    Digital Repository Service at National Institute of Oceanography (India)

    Achuthankutty, C.T.

    Larval stages of the penaeid shrimps, Metapenaeus dobsoni (Miers), M. affinis (Milne - Edwards) and Penaeus merguiensis De Man were mostly distributed at the lower reaches of Mandovi and Zuari estuaries. While larvae of M. dobsoni and M. affinis...

  14. De la antigüedad del hombre en el Plata a la distribución de las antigüedades en el mapa: los criterios de organización de las colecciones antropológicas del Museo de La Plata entre 1897 y 1930 From the antiquity of man in Argentina’s Plata region to the distribution of antiquities across the map: the organization of the Museu de La Plata’s anthropological colletion, 1897-1930

    Directory of Open Access Journals (Sweden)

    Irina Podgorny

    1999-06-01

    Full Text Available En este trabajo se analizan los criterios de organización de las colecciones antropológicas del Museo de La Plata vigentes entre 1897 y 1930. Bajo el nombre de ‘antropológicas’ se incluyen las colecciones correspondientes a las exhibiciones de las salas de antropología, etnografía y arqueología. Aunque el criterio que finalmente imperó fue el ordenamiento por regiones geográficas, según el sistema de Enrique Delachaux, se discutirán además las otras posibilidades de ordenamiento (etnológico, lingüístico y cronológico que aunque conocidas por las autoridades y científicos del Museo de La Plata fueron descartadas.The article analyzes the criteria for arranging and classifying anthropological collections (that is, anthropology, ethnography, and archeology exhibit rooms adopted at the Museo de La Plata during 1897-1930. The criterion ultimately selected was arrangement by geographical regions, using a system devised by Enrique Delachaux. The article examines other rules of classification as well, familiar to the museum’s curators and scientists but rejected by them: ethnological, linguistic, and chronological criteria.

  15. Methane and nitrous oxide emissions from a subtropical estuary (the Brisbane River estuary, Australia)

    Energy Technology Data Exchange (ETDEWEB)

    Musenze, Ronald S.; Werner, Ursula [Advanced Water Management Centre (AWMC), the University of Queensland, Brisbane, Qld 4072 (Australia); Grinham, Alistair [Advanced Water Management Centre (AWMC), the University of Queensland, Brisbane, Qld 4072 (Australia); School of Civil Engineering, the University of Queensland, Brisbane, Qld 4072 (Australia); Udy, James [Healthy Waterways Ltd, P.O. Box 13086, George Street, Brisbane, Qld 4003 (Australia); Yuan, Zhiguo, E-mail: z.yuan@awmc.uq.edu.au [Advanced Water Management Centre (AWMC), the University of Queensland, Brisbane, Qld 4072 (Australia)

    2014-02-01

    Methane (CH{sub 4}) and nitrous oxide (N{sub 2}O) are two key greenhouse gases. Their global atmospheric budgeting is, however, flout with challenges partly due to lack of adequate field studies determining the source strengths. Knowledge and data limitations exist for subtropical and tropical regions especially in the southern latitudes. Surface water methane and nitrous oxide concentrations were measured in a subtropical estuarine system in the southern latitudes in an extensive field study from 2010 to 2012 and water–air fluxes estimated using models considering the effects of both wind and flow induced turbulence. The estuary was found to be a strong net source of both CH{sub 4} and N{sub 2}O all-year-round. Dissolved N{sub 2}O concentrations ranged between 9.1 ± 0.4 to 45.3 ± 1.3 nM or 135 to 435% of atmospheric saturation level, while CH{sub 4} concentrations varied between 31.1 ± 3.7 to 578.4 ± 58.8 nM or 1210 to 26,430% of atmospheric saturation level. These results compare well with measurements from tropical estuarine systems. There was strong spatial variability with both CH{sub 4} and N{sub 2}O concentrations increasing upstream the estuary. Strong temporal variability was also observed but there were no clear seasonal patterns. The degree of N{sub 2}O saturation significantly increased with NO{sub x} concentrations (r{sup 2} = 0.55). The estimated water–air fluxes varied between 0.1 and 3.4 mg N{sub 2}O m{sup −2} d{sup −1} and 0.3 to 27.9 mg CH{sub 4} m{sup −2} d{sup −1}. Total emissions (CO{sub 2}-e) were N{sub 2}O (64%) dominated, highlighting the need for reduced nitrogen inputs into the estuary. Choice of the model(s) for estimation of the gas transfer velocity had a big bearing on the estimated total emissions. - Highlights: • The estuary is a strong source of atmospheric methane and nitrous oxide. • Emissions had strong spatial-temporal variability with unclear seasonal patterns. • Dissolved gas saturation comparable to that

  16. Methane and nitrous oxide emissions from a subtropical estuary (the Brisbane River estuary, Australia)

    International Nuclear Information System (INIS)

    Musenze, Ronald S.; Werner, Ursula; Grinham, Alistair; Udy, James; Yuan, Zhiguo

    2014-01-01

    Methane (CH 4 ) and nitrous oxide (N 2 O) are two key greenhouse gases. Their global atmospheric budgeting is, however, flout with challenges partly due to lack of adequate field studies determining the source strengths. Knowledge and data limitations exist for subtropical and tropical regions especially in the southern latitudes. Surface water methane and nitrous oxide concentrations were measured in a subtropical estuarine system in the southern latitudes in an extensive field study from 2010 to 2012 and water–air fluxes estimated using models considering the effects of both wind and flow induced turbulence. The estuary was found to be a strong net source of both CH 4 and N 2 O all-year-round. Dissolved N 2 O concentrations ranged between 9.1 ± 0.4 to 45.3 ± 1.3 nM or 135 to 435% of atmospheric saturation level, while CH 4 concentrations varied between 31.1 ± 3.7 to 578.4 ± 58.8 nM or 1210 to 26,430% of atmospheric saturation level. These results compare well with measurements from tropical estuarine systems. There was strong spatial variability with both CH 4 and N 2 O concentrations increasing upstream the estuary. Strong temporal variability was also observed but there were no clear seasonal patterns. The degree of N 2 O saturation significantly increased with NO x concentrations (r 2 = 0.55). The estimated water–air fluxes varied between 0.1 and 3.4 mg N 2 O m −2 d −1 and 0.3 to 27.9 mg CH 4 m −2 d −1 . Total emissions (CO 2 -e) were N 2 O (64%) dominated, highlighting the need for reduced nitrogen inputs into the estuary. Choice of the model(s) for estimation of the gas transfer velocity had a big bearing on the estimated total emissions. - Highlights: • The estuary is a strong source of atmospheric methane and nitrous oxide. • Emissions had strong spatial-temporal variability with unclear seasonal patterns. • Dissolved gas saturation comparable to that in tropical rivers and polluted estuaries. • Emissions are dominated by N2O, which

  17. Protección ambiental del Río de la Plata y su frente marítimo: el marco jurídico general

    Directory of Open Access Journals (Sweden)

    Heber Arbuet Vignali

    2014-07-01

    Full Text Available Versión escrita de la conferencia dictada en el Simposio sobre aspectos jurídicos de la protección ambiental del Río de la Plata y su Frente Marítimo (Montevideo: 21 nov.2001Contenido: Introducción. Importancia del derecho en las relaciones humanas. Importancia del derecho en el asunto que nos convoca. El polifacético marco jurídico de este proyecto. La aparición de los nuevos sistemas. La nueva realidad socio política que debe ser regulada jurídicamente. Importancia de estas ideas para la protección ambiental en el Plata

  18. Ambientes de sedimentación vinculados al acuífero Puelche en la región de La Plata

    OpenAIRE

    García, Juan Manuel; Kruse, Eduardo; Deluchi, Marta

    2016-01-01

    Se plantea una actualización de las características dimensionales e interpretación del ambiente de sedimentación en función de las características morfológicas de la base y el techo del Acuífero Puelche en el área abarcada por las cuencas hidrográficas que drenan hacia el Río de la Plata en los Partidos de Berisso, Ensenada y La Plata (Provincia de Buenos Aires). La metodología incluyó la recopilación y revisión de perfiles de perforación antiguos y recientes, los cuales permitieron la elabor...

  19. Cladocerans (Branchiopoda) of a tropical estuary in Brazil

    OpenAIRE

    Paranaguá, M. N; Neumann-Leitão, S; Nogueira-Paranhos, J. D; Silva, T. A.; Matsumura-Tundisi, T.

    2005-01-01

    The study was conducted in the Capibaribe river estuary in Recife (Brazil) to assess the role played by cladocerans in a eutrophic environment. Samplings were carried out monthly at 4 fixed stations along the estuary from July 1987 to June 1988. Collections were made with a plankton net of 65 micrometers mesh size. Six cladocerans species were registered: Penilia avirostris, Diaphanosoma spinulosum, Chydorus barroisi, Ceriodaphnia rigaudi, Ilyocryptus spinifer, and Moina micrura. The most fre...

  20. Contamination and restoration of an estuary affected by phosphogypsum releases

    International Nuclear Information System (INIS)

    Villa, M.; Mosqueda, F.; Hurtado, S.; Mantero, J.; Manjon, G.; Perianez, R.; Vaca, F.; Garcia-Tenorio, R.

    2009-01-01

    The Huelva Estuary in Huelva, Spain, has been one of the most studied environmental compartments in the past years from the point of view of naturally occurring radioactive material (NORM) releases. It has been historically affected by waste releases, enriched in radionuclides from the U-decay series, from factories located in the area devoted to the production of phosphoric acid and phosphate fertilizers. Nevertheless, changes in national regulations forced a new waste management practice in 1998, prohibiting releases of phosphogypsum into the rivers. The input of natural radionuclides from phosphate factories to rivers was drastically reduced. Because of this there was a unique opportunity for the study of the response of a contaminated environmental compartment, specifically an estuary affected by tidal influences, after the cessation of the contaminant releases to, in this case, the Huelva Estuary (henceforth referred to as the Estuary). To investigate the environmental response to this new discharge regime, the specific activities of radionuclides 226 Ra and 210 Pb in water and sediment samples collected in four campaigns (from 1999 to 2005) were determined and compared with pre-1998 values. From this study it is possible to infer the most effective mechanisms of decontamination for the Estuary. Decontamination rates of 210 Pb and 226 Ra in the sediments and water have been calculated using exponential fittings and corresponding half-lives have been deduced from them. The cleaning half-life in the whole area of the Estuary is about 6 and 3.5 years for 226 Ra and 210 Pb respectively. The observed trend clearly shows that contamination of the Estuary by natural radionuclides is now decreasing and radioactive levels in waters and sediments are approaching the natural background references. This work attempts to evaluate whether it can be expected that the decontamination of the enhanced levels of natural radioactivity in the Estuary can be performed via natural

  1. Juvenile salmon usage of the Skeena River estuary.

    Science.gov (United States)

    Carr-Harris, Charmaine; Gottesfeld, Allen S; Moore, Jonathan W

    2015-01-01

    Migratory salmon transit estuary habitats on their way out to the ocean but this phase of their life cycle is more poorly understood than other phases. The estuaries of large river systems in particular may support many populations and several species of salmon that originate from throughout the upstream river. The Skeena River of British Columbia, Canada, is a large river system with high salmon population- and species-level diversity. The estuary of the Skeena River is under pressure from industrial development, with two gas liquefaction terminals and a potash loading facility in various stages of environmental review processes, providing motivation for understanding the usage of the estuary by juvenile salmon. We conducted a juvenile salmonid sampling program throughout the Skeena River estuary in 2007 and 2013 to investigate the spatial and temporal distribution of different species and populations of salmon. We captured six species of juvenile anadromous salmonids throughout the estuary in both years, and found that areas proposed for development support some of the highest abundances of some species of salmon. Specifically, the highest abundances of sockeye (both years), Chinook in 2007, and coho salmon in 2013 were captured in areas proposed for development. For example, juvenile sockeye salmon were 2-8 times more abundant in the proposed development areas. Genetic stock assignment demonstrated that the Chinook salmon and most of the sockeye salmon that were captured originated from throughout the Skeena watershed, while some sockeye salmon came from the Nass, Stikine, Southeast Alaska, and coastal systems on the northern and central coasts of British Columbia. These fish support extensive commercial, recreational, and First Nations fisheries throughout the Skeena River and beyond. Our results demonstrate that estuary habitats integrate species and population diversity of salmon, and that if proposed development negatively affects the salmon populations that

  2. Contamination and restoration of an estuary affected by phosphogypsum releases

    Energy Technology Data Exchange (ETDEWEB)

    Villa, M., E-mail: mvilla@us.es [Centro de Investigacion, Tecnologia e Innovacion, Universidad de Sevilla CITIUS, Av. Reina Mercedes 4B, E41012-Sevilla (Spain); Mosqueda, F. [Dpto. de Fisica Aplicada, Facultad de Ciencias Experimentales, Universidad de Huelva, Campus de El Carmen, 21007-Huelva (Spain); Hurtado, S. [Centro de Investigacion, Tecnologia e Innovacion, Universidad de Sevilla CITIUS, Av. Reina Mercedes 4B, E41012-Sevilla (Spain); Mantero, J.; Manjon, G. [E. T. S. Arquitectura, Universidad de Sevilla, Departamento de Fisica Aplicada II, Av. Reina Mercedes, 2. 41012-Sevilla (Spain); Perianez, R. [E.U.I.T.A., Universidad de Sevilla, Departamento de Fisica Aplicada III, Carretera de Utrera, Km. 1, 41013 Sevilla (Spain); Vaca, F. [Dpto. de Fisica Aplicada, Facultad de Ciencias Experimentales, Universidad de Huelva, Campus de El Carmen, 21007-Huelva (Spain); Garcia-Tenorio, R. [E. T. S. Arquitectura, Universidad de Sevilla, Departamento de Fisica Aplicada II, Av. Reina Mercedes, 2. 41012-Sevilla (Spain)

    2009-12-15

    The Huelva Estuary in Huelva, Spain, has been one of the most studied environmental compartments in the past years from the point of view of naturally occurring radioactive material (NORM) releases. It has been historically affected by waste releases, enriched in radionuclides from the U-decay series, from factories located in the area devoted to the production of phosphoric acid and phosphate fertilizers. Nevertheless, changes in national regulations forced a new waste management practice in 1998, prohibiting releases of phosphogypsum into the rivers. The input of natural radionuclides from phosphate factories to rivers was drastically reduced. Because of this there was a unique opportunity for the study of the response of a contaminated environmental compartment, specifically an estuary affected by tidal influences, after the cessation of the contaminant releases to, in this case, the Huelva Estuary (henceforth referred to as the Estuary). To investigate the environmental response to this new discharge regime, the specific activities of radionuclides {sup 226}Ra and {sup 210}Pb in water and sediment samples collected in four campaigns (from 1999 to 2005) were determined and compared with pre-1998 values. From this study it is possible to infer the most effective mechanisms of decontamination for the Estuary. Decontamination rates of {sup 210}Pb and {sup 226}Ra in the sediments and water have been calculated using exponential fittings and corresponding half-lives have been deduced from them. The cleaning half-life in the whole area of the Estuary is about 6 and 3.5 years for {sup 226}Ra and {sup 210}Pb respectively. The observed trend clearly shows that contamination of the Estuary by natural radionuclides is now decreasing and radioactive levels in waters and sediments are approaching the natural background references. This work attempts to evaluate whether it can be expected that the decontamination of the enhanced levels of natural radioactivity in the Estuary

  3. Continuous resistivity profiling data from the Corsica River Estuary, Maryland

    Science.gov (United States)

    Cross, V.A.; Bratton, J.F.; Worley, C.R.; Crusius, J.; Kroeger, K.D.

    2011-01-01

    Submarine groundwater discharge (SGD) into Maryland's Corsica River Estuary was investigated as part of a larger study to determine its importance in nutrient delivery to the Chesapeake Bay. The Corsica River Estuary represents a coastal lowland setting typical of much of the eastern bay. An interdisciplinary U.S. Geological Survey (USGS) science team conducted field operations in the lower estuary in April and May 2007. Resource managers are concerned about nutrients that are entering the estuary via SGD that may be contributing to eutrophication, harmful algal blooms, and fish kills. Techniques employed in the study included continuous resistivity profiling (CRP), piezometer sampling of submarine groundwater, and collection of a time series of radon tracer activity in surface water. A CRP system measures electrical resistivity of saturated subestuarine sediments to distinguish those bearing fresh water (high resistivity) from those with saline or brackish pore water (low resistivity). This report describes the collection and processing of CRP data and summarizes the results. Based on a grid of 67.6 kilometers of CRP data, low-salinity (high-resistivity) groundwater extended approximately 50-400 meters offshore from estuary shorelines at depths of 5 to >12 meters below the sediment surface, likely beneath a confining unit. A band of low-resistivity sediment detected along the axis of the estuary indicated the presence of a filled paleochannel containing brackish groundwater. The meandering paleochannel likely incised through the confining unit during periods of lower sea level, allowing the low-salinity groundwater plumes originating from land to mix with brackish subestuarine groundwater along the channel margins and to discharge. A better understanding of the spatial variability and geological controls of submarine groundwater flow beneath the Corsica River Estuary could lead to improved models and mitigation strategies for nutrient over-enrichment in the

  4. Hydro-morphological modelling of small, wave-dominated estuaries

    Science.gov (United States)

    Slinger, Jill H.

    2017-11-01

    Small, intermittently open or closed estuaries are characteristic of the coasts of South Africa, Australia, California, Mexico and many other areas of the world. However, modelling attention has tended to focus on big estuaries that drain large catchments and serve a wide diversity of interests e.g. agriculture, urban settlement, recreation, commercial fishing. In this study, the development of a simple, parametric, system dynamics model to simulate the opening and closure of the mouths of small, wave-dominated estuaries is reported. In the model, the estuary is conceived as a basin with a specific water volume to water level relationship, connected to the sea by a channel of fixed width, but variable sill height. Changes in the form of the basin are not treated in the model, while the dynamics of the mouth channel are central to the model. The magnitude and direction of the flow through the mouth determines whether erosion or deposition of sediment occurs in the mouth channel, influencing the sill height. The model is implemented on the Great Brak Estuary in South Africa and simulations reveal that the raised low water levels in the estuary during spring tide relative to neap tide, are occasioned by the constriction of the tidal flow through the shallow mouth. Freshwater inflows to the estuary are shown to be significant in determining the behaviour of the inlet mouth, a factor often ignored in studies on tidal inlets. Further it is the balance between freshwater inflows and wave events that determines the opening or closure of the mouth of a particular estuary.

  5. Functional diversity of fish in estuaries at a global extent

    OpenAIRE

    Rita P Vasconcelos; Sébastien Villéger; François Guilhaumon

    2015-01-01

    Biodiversity is currently viewed as a framework encompassing multiple facets of the variety of life, including taxonomic and functional aspects. Species richness and composition of fish assemblages in estuaries is defined by global to local processes acting on community colonization. The present study further investigates how biodiversity of fish assemblages varies among estuaries globally, by simultaneously analysing taxonomic and functional richness and diversity of assemblages. A comprehen...

  6. Modern sedimentary environments in a large tidal estuary, Delaware Bay

    Science.gov (United States)

    Knebel, H.J.

    1989-01-01

    Data from an extensive grid of sidescan-sonar records reveal the distribution of sedimentary environments in the large, tidally dominated Delaware Bay estuary. Bathymetric features of the estuary include large tidal channels under the relatively deep (> 10 m water depth) central part of the bay, linear sand shoals (2-8 m relief) that parallel the sides of the tidal channels, and broad, low-relief plains that form the shallow bay margins. The two sedimentary environments that were identified are characterized by either (1) bedload transport and/or erosion or (2) sediment reworking and/or deposition. Sand waves and sand ribbons, composed of medium to coarse sands, define sites of active bedload transport within the tidal channels and in gaps between the linear shoals. The sand waves have spacings that vary from 1 to 70 m, amplitudes of 2 m or less, and crestlines that are usually straight. The orientations of the sand waves and ribbons indicate that bottom sediment movement may be toward either the northwest or southeast along the trends of the tidal channels, although sand-wave asymmetry indicates that the net bottom transport is directed northwestward toward the head of the bay. Gravelly, coarse-grained sediments, which appear as strongly reflective patterns on the sonographs, are also present along the axes and flanks of the tidal channels. These coarse sediments are lag deposits that have developed primarily where older strata were eroded at the bay floor. Conversely, fine sands that compose the linear shoals and muddy sands that cover the shallow bay margins appear mainly on the sonographs either as smooth featureless beds that have uniform light to moderate shading or as mosaics of light and dark patches produced by variations in grain size. These acoustic and textural characteristics are the result of sediment deposition and reworking. Data from this study (1) support the hypothesis that bed configurations under deep tidal flows are functions of current

  7. On the sedimentation problems in water abstraction channels at power plant sites at tidal estuaries

    International Nuclear Information System (INIS)

    Jensen, J.; Arns, A.; Frank, T.; Meiswinkel, R.; Richei, A.

    2010-01-01

    The required cooling water supply of a nuclear power plant the required flow deepness in the water abstraction channels has to be provided. Since the abstraction channels are usually in main stream orientation of the river periodic sedimentation occur, that have to be removed by dredging techniques. Especially in tidal estuaries the complex flow situation induces transport mechanisms that have to be studied in order to develop cost saving and effective measures and procedures to reduce the sedimentation and pollutants deposition. The authors recommend experimental determinations of the sold material transport and numerical hydrodynamic transport modeling to identify the transport pathways.

  8. Population structure of an invasive parthenogenetic gastropod in coastal lakes and estuaries of northern KwaZulu-Natal, South Africa.

    Directory of Open Access Journals (Sweden)

    Nelson A F Miranda

    Full Text Available BACKGROUND: Estuaries and coastal lakes receive little attention despite being heavily invaded by non-indigenous invasive species (NIS. In these situations, studies of population dynamics in invaded habitats can provide valuable insights into how NIS interact with new environments. Tarebia granifera is a prosobranch gastropod from south-east Asia which has invaded other sub-tropical parts of the world. This study addresses whether a small number of key environmental factors influences gastropod communities, and specifically how the population density and size structure of T. granifera were influenced by environmental change in estuaries and coastal lakes in southern Africa. METHODOLOGY/PRINCIPAL FINDINGS: T. granifera's density, number of brooded juveniles and size structure were measured at the St. Lucia Estuary, Mgobozeleni Estuary, Lake Sibaya and Lake Nhlange. Size structure was classified according to shell height (SH. All dissected individuals were found to be female and free from trematode infection. Salinity, water depth, temperature, and pH were the main factors correlated with population density of gastropod communities. T. granifera often reached densities well over 1000 ind. m(-2, displacing indigenous gastropods and becoming a dominant component of the benthic community. T. granifera successfully invaded estuaries despite frequent exposure to high salinity and desiccation, which could together eliminate >97% of the population. The persistence of T. granifera was ensured due to its high fecundity and the environmental tolerance of large adults (20-30 mm SH which carried an average of 158±12.8 SD brooded juveniles. Repeat introductions were not essential for the success of this parthenogenetic NIS. CONCLUSION/SIGNIFICANCE: There is a need for a broader study on the reproductive biology of T. granifera (including the previously overlooked "brood pouch ecology", which affects population dynamics and may be relevant to other

  9. Functional diversity of fish in tropical estuaries: A traits-based approach of communities in Pernambuco, Brazil

    Science.gov (United States)

    Silva-Júnior, C. A. B.; Mérigot, B.; Lucena-Frédou, F.; Ferreira, B. P.; Coxey, M. S.; Rezende, S. M.; Frédou, T.

    2017-11-01

    Environmental changes and human activities may have strong impacts on biodiversity and ecosystem functioning. While biodiversity is traditionally based on species richness and composition, there is a growing concern to take into account functional diversity to assess and manage species communities. In spite of their economic importance, functional diversity quantified by a traits-based approach is still poorly documented in tropical estuaries. In this study, the functional diversity of fishes was investigated within four estuaries in Pernambuco state, northeast of Brazil. These areas are subject to different levels of human impact (e.g. mangrove deforestation, shrimp farming, fishing etc.) and environmental conditions. Fishes were collected during 34 scientific surveys. A total of 122 species were identified and 12 functional traits were quantified describing two main functions: food acquisition and locomotion. Fish abundance and functional dissimilarities data were combined into a multivariate analysis, the Double Principal Coordinate Analysis, to identify the functional typology of fish assemblages according to the estuary. Results showed that Itapissuma, the largest estuary with a wider mangrove forest area, differs from the other three estuaries, showing higher mean values per samples of species richness S and quadratic entropy Q. Similarly, it presented a different functional typology (the first two axes of the DPCoA account for 68.7% of total inertia, while those of a traditional PCA based solely on species abundances provided only 17.4%). Conversely, Suape, Sirinhaém, and to a lower extent Rio Formoso, showed more similarity in their diversity. This result was attributed to their predominantly marine influenced hydrological features, and similar levels of species abundances and in morphological traits. Overall, this study, combining diversity indices and a recent multivariate analysis to access species contribution to functional typology, allows to deepen

  10. Facilitation of the Estuary/Ocean Subgroup and the Expert Regional Technical Group, Annual Report for 2015

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Gary E. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2015-08-01

    This document is the annual report for the period September 1, 2014 through August 31, 2015 for the project—Facilitation of the Estuary/Ocean Subgroup (EOS) and the Expert Regional Technical Group (ERTG). Pacific Northwest National Laboratory (PNNL) conducted the project for the Bonneville Power Administration (BPA). The EOS and ERTG are part of the research, monitoring, and evaluation (RME) and habitat restoration efforts, respectively, developed by the Action Agencies (BPA, U.S. Army Corps of Engineers [Corps or USACE], and U.S. Bureau of Reclamation) in response to obligations arising from the Endangered Species Act as a result of operation of the Federal Columbia River Power System (FCRPS) and implemented under the Columbia Estuary Ecosystem Restoration Program (CEERP). BPA/Corps (2015) explain the CEERP and the role of RME and the ERTG. For the purposes of this report, the lower Columbia River and estuary (LCRE) includes the floodplain from Bonneville Dam down through the lower river and estuary into the river’s plume in the ocean. The main purpose of this project is to facilitate EOS and ERTG meetings and work products. Other purposes are to provide technical support for CEERP adaptive management, CEERP restoration design challenges, and tributary RME. From 2002 through 2008, the EOS worked to design the federal RME program for the estuary/ocean (Johnson et al. 2008). From 2009 to the present day, EOS activities have involved RME implementation; however, EOS activities were minimal during the current reporting period. PNNL provided technical support to CEERP’s adaptive management process by convening 1.2 meetings of the Action Agencies (AAs) and drafting material for the “CEERP 2015 Restoration and Monitoring Plan” (BPA/Corps 2015).

  11. Síntesis y Caracterización de Ag2Cu2O3, el primer óxido de cobre y plata

    Directory of Open Access Journals (Sweden)

    Gómez-Romero, P.

    2000-06-01

    Full Text Available Despite the crystal-chemical similarities between copper and silver ions, there is no known silver copper oxide, neither natural nor synthetic. In this work, we present the synthesis at room-temperature of the first silver copper oxide of formula Ag2Cu2O3 (tetragonal, a=5.8857(3Å, c=10.6868(7Å, space group I41/amd, Z=4. It should be noted that the thermal stability of this new oxide is enhanced with respect to Ag2O or even CuO. The structure consists of alternating chains of edge-sharing square planar Cu(II and zigzag chains of linearly coordinated Ag(I ions.A pesar de las similitudes cristaloquímicas entre los iones de cobre y los de plata, no existe ningún óxido mixto de cobre y plata ni natural ni sintético. En este trabajo se presenta la síntesis a bajas temperaturas del primer óxido mixto de cobre y plata, de fórmula Ag2Cu2O3 (tetragonal, a=5.8857(3Å, c=10.6868(7Å, grupo espacial I41/amd, Z=4. Este óxido posee una estabilidad térmica superior a los correspondientes óxidos de cobre y de plata. Contiene cadenas de iones Cu(II cuadrado-planos que alternan con cadenas en zig-zag de Ag(I con coordinación lineal.

  12. Mario Bunge en la Universidad Nacional de La Plata : Breve testimonio de su visita en el año 2000

    OpenAIRE

    Bunge, Mario

    2000-01-01

    Radio Universidad Nacional de La Plata registra un breve testimonio del Dr. Mario Bunge en su visita a la UNLP en el año 2000. Resalta su paso por esta Universidad, así como las características de la misma. Mario Augusto Bunge: nació en Buenos Aires el 21 de septiembre de 1919. Físico y filósofo, se graduó en la UNLP en 1952. Reside en Montreal (Canadá).

  13. Contribución a la identificación de esporas del Reino Fungi en la atmósfera de La Plata, Argentina

    OpenAIRE

    Nitiu, Daniela S.; Mallo, Andrea C.; Gardella Sambeth, María C.; Morbelli, Marta A.

    2010-01-01

    Based on the aeromycological analysis of La Plata city, artificial Morphological Groups of fungal spores were defined. This study is a methodological contribution to the identification and counting of a fraction of the atmospheric micobiota. For the definition of groups, the criteria of Saccardo (1886) were taken into account and the groupings created by Díaz et al. (1998) and Aira et al. (2005) have been reformulated. Four new groups have been created and other sporal types have be...

  14. Upstream Freshwater and Terrestrial Sources Are Differentially Reflected in the Bacterial Community Structure along a Small Arctic River and Its Estuary

    Science.gov (United States)

    Hauptmann, Aviaja L.; Markussen, Thor N.; Stibal, Marek; Olsen, Nikoline S.; Elberling, Bo; Bælum, Jacob; Sicheritz-Pontén, Thomas; Jacobsen, Carsten S.

    2016-01-01

    Glacier melting and altered precipitation patterns influence Arctic freshwater and coastal ecosystems. Arctic rivers are central to Arctic water ecosystems by linking glacier meltwaters and precipitation with the ocean through transport of particulate matter and microorganisms. However, the impact of different water sources on the microbial communities in Arctic rivers and estuaries remains unknown. In this study we used 16S rRNA gene amplicon sequencing to assess a small river and its estuary on the Disko Island, West Greenland (69°N). Samples were taken in August when there is maximum precipitation and temperatures are high in the Disko Bay area. We describe the bacterial community through a river into the estuary, including communities originating in a glacier and a proglacial lake. Our results show that water from the glacier and lake transports distinct communities into the river in terms of diversity and community composition. Bacteria of terrestrial origin were among the dominating OTUs in the main river, while the glacier and lake supplied the river with water containing fewer terrestrial organisms. Also, more psychrophilic taxa were found in the community supplied by the lake. At the river mouth, the presence of dominant bacterial taxa from the lake and glacier was unnoticeable, but these taxa increased their abundances again further into the estuary. On average 23% of the estuary community consisted of indicator OTUs from different sites along the river. Environmental variables showed only weak correlations with community composition, suggesting that hydrology largely influences the observed patterns. PMID:27708629

  15. Upstream freshwater and terrestrial sources are differentially reflected in the bacterial community structure along a small Arctic river and its estuary

    Directory of Open Access Journals (Sweden)

    Aviaja Lyberth Hauptmann

    2016-09-01

    Full Text Available Glacier melting and altered precipitation patterns influence Arctic freshwater and coastal ecosystems. Arctic rivers are central to Arctic water ecosystems by linking glacier meltwaters and precipitation with the ocean through transport of particulate matter and microorganisms. However, the impact of different water sources on the microbial communities in Arctic rivers and estuaries remains unknown. In this study we used 16S rRNA gene amplicon sequencing to assess a small river and its estuary on the Disko Island, West Greenland (69°N. Samples were taken in August when there is maximum precipitation and temperatures are high in the Disko Bay area. We describe the bacterial community through a river into the estuary, including communities originating in a glacier and a proglacial lake. Our results show that water from the glacier and lake transports distinct communities into the river in terms of diversity and community composition. Bacteria of terrestrial origin were among the dominating OTUs in the main river, while the glacier and lake supplied the river with water containing fewer terrestrial organisms. Also, more psychrophilic taxa were found in the community supplied by the lake. At the river mouth, the presence of dominant bacterial taxa from the lake and glacier was unnoticeable, but these taxa increased their abundances again further into the estuary. On average 23% of the estuary community consisted of indicator OTUs from different sites along the river. Environmental variables showed only weak correlations with community composition, suggesting that hydrology largely influences the observed patterns.

  16. Sources, Ages, and Alteration of Organic Matter in Estuaries.

    Science.gov (United States)

    Canuel, Elizabeth A; Hardison, Amber K

    2016-01-01

    Understanding the processes influencing the sources and fate of organic matter (OM) in estuaries is important for quantifying the contributions of carbon from land and rivers to the global carbon budget of the coastal ocean. Estuaries are sites of high OM production and processing, and understanding biogeochemical processes within these regions is key to quantifying organic carbon (Corg) budgets at the land-ocean margin. These regions provide vital ecological services, including nutrient filtration and protection from floods and storm surge, and provide habitat and nursery areas for numerous commercially important species. Human activities have modified estuarine systems over time, resulting in changes in the production, respiration, burial, and export of Corg. Corg in estuaries is derived from aquatic, terrigenous, and anthropogenic sources, with each source exhibiting a spectrum of ages and lability. The complex source and age characteristics of Corg in estuaries complicate our ability to trace OM along the river-estuary-coastal ocean continuum. This review focuses on the application of organic biomarkers and compound-specific isotope analyses to estuarine environments and on how these tools have enhanced our ability to discern natural sources of OM, trace their incorporation into food webs, and enhance understanding of the fate of Corg within estuaries and their adjacent waters.

  17. Wind Wave Behavior in Fetch and Depth Limited Estuaries

    Science.gov (United States)

    Karimpour, Arash; Chen, Qin; Twilley, Robert R.

    2017-01-01

    Wetland dominated estuaries serve as one of the most productive natural ecosystems through their ecological, economic and cultural services, such as nursery grounds for fisheries, nutrient sequestration, and ecotourism. The ongoing deterioration of wetland ecosystems in many shallow estuaries raises concerns about the contributing erosive processes and their roles in restraining coastal restoration efforts. Given the combination of wetlands and shallow bays as landscape components that determine the function of estuaries, successful restoration strategies require knowledge of wind wave behavior in fetch and depth limited water as a critical design feature. We experimentally evaluate physics of wind wave growth in fetch and depth limited estuaries. We demonstrate that wave growth rate in shallow estuaries is a function of wind fetch to water depth ratio, which helps to develop a new set of parametric wave growth equations. We find that the final stage of wave growth in shallow estuaries can be presented by a product of water depth and wave number, whereby their product approaches 1.363 as either depth or wave energy increases. Suggested wave growth equations and their asymptotic constraints establish the magnitude of wave forces acting on wetland erosion that must be included in ecosystem restoration design.

  18. Petroleum hydrocarbons in a water-sediment system from Yellow River estuary and adjacent coastal area, China: Distribution pattern, risk assessment and sources.

    Science.gov (United States)

    Wang, Min; Wang, Chuanyuan; Li, Yuanwei

    2017-09-15

    Aliphatic hydrocarbons (AHs), biomarker and polycyclic aromatic hydrocarbons (PAHs) concentrations of surface water and sediment samples collected from Yellow River Estuary and adjacent coastal area in China were measured to determine their spatial distributions, analyze their sources and evaluate the ecological risk of PAHs in the water-sediment system. The spatial distributions of n-alkane in sediments are mainly controlled by the mixing inputs of terrigenous and marine components. In comparison with AHs, the total concentrations of Σ16PAHs in surface sediments from a transect of the offshore area were noticeably higher than that of the riverine and estuary areas. Additionally, the AHs and total PAHs concentrations all indicated an overall pattern of a seaward decrease. The PAHs concentrations during the dry season (mainly in the form of dissolved phase) were higher than that of PAHs (mainly dissolved phase and particulate phase form) in the flooding season. In comparison with global concentration levels of PAHs, the level of PAHs in suspended particulate matter and sediments from the Yellow River Estuary was lower than those from other countries, while the concentration of PAHs in the dissolved phase were in the middle range. Petroleum contamination, mainly from oil exploration and discharge of pollutants from rivers, was the main source of n-alkanes. The PAHs in the river were mostly of petrogenic origin, while those in the estuarial and marine areas originated mainly from pyrogenic sources. The results of the toxicology assessment suggested that the PAHs in sediments from Yellow River Estuary and adjacent coastal area exhibited a low potential eco-toxicological contamination level. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. Probable movement and mixing of contaminants in tidal estuaries - A field study in Kundalika Estuary, west coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    DineshKumar, P.K.; Sarma, R.V.; Zingde, M.D.

    The probable movement and mixing of contaminants within and through the Kundalika river estuary along the west coast of India are studied Neutrally buoyant biplane drogues, floats and dye were tracked at different stages of the tide to assess...

  20. Maine's Employability Skills Program

    Science.gov (United States)

    McMahon, John M.; Wolffe, Karen E.; Wolfe, Judy; Brooker, Carrie

    2013-01-01

    This Practice Report describes the development and implementation of the "Maine Employability Skills Program," a model employment program developed by the Maine Division for the Blind and Visually Impaired (DBVI). The program was designed to support the efforts of the chronically unemployed or underemployed. These consumers were either…

  1. Distribution and assessment of sediment toxicity in Tamaki Estuary, Auckland, New Zealand

    Science.gov (United States)

    Abrahim, G. M. S.; Parker, R. J.; Nichol, S. L.

    2007-07-01

    Heavy metal levels in surface sediments from Tamaki Estuary demonstrate significant up estuary increases in Cu, Pb, Zn, Cd and mud concentrations. Increased metal levels towards the head of the estuary are linked to local catchment sources reflecting the historical development, industrialisation and urbanisation of catchment areas surrounding the upper estuary. The relatively narrow constriction in the middle estuary (Panmure area), makes it susceptible to accumulation of upper estuary pollutants, since the constriction reduces circulation and extends the time required for fine waterborne sediments in the upper estuary to exchange with fresh coastal water. As a result fine fraction sediments trapped in the upper estuary facilitate capture and retention of pollutants at the head of the estuary. The increase in sandy mud poor sediments towards the mouth of the estuary is associated with generally low metal concentrations. The estuary’s geomorphic shape with a mid estuary constriction, sediment texture and mineralogy and catchment history are significant factors in understanding the overall spatial distribution of contaminants in the estuary. Bulk concentration values for Cu, Pb, Zn, and Cd in all the studied surface samples occur below ANZECC ISQG-H toxicity values. Cd and Cu concentrations are also below the ISQG-L toxicity levels for these elements. However, Pb and Zn concentrations do exceed the ISQG-L values in some of the surface bulk samples in the upper estuary proximal to long established sources of catchment pollution.

  2. Análisis de las causas de muerte de los primeros habitantes de la ciudad de La Plata (1887

    Directory of Open Access Journals (Sweden)

    Flores, Olga B.

    2003-01-01

    Full Text Available El presente trabajo constituye un estudio preliminar que forma parte de un proyecto más amplio acreditado por la Universidad Nacional de La Plata y avalado por la Municipalidad de esa localidad "El Cementerio de La Plata. Su contexto histórico". Nuestra investigación se basó fundamentalmente en el análisis de las actas de defunción del Archivo del Cementerio Municipal con el fin de indagar sobre la incidencia diferencial o no de las causas de muerte en relación con la nacionalidad, el sexo, la edad, la profesión, entre otras. Estos datos fueron volcados en planillas con las que se sistematizó la información para toda la población. A partir de esta población, se determinó una muestra compuesta por todos los individuos de ambos sexos que se encuentran en las sepulturas en tierra y abarca el primer año de funcionamiento del Cementerio Municipal. El objetivo del presente trabajo fue caracterizar cómo se distribuyeron las causas de muerte y su incidencia sobre los grupos de edad, género y grupo social, en los decesos ocurridos durante 1887. Según se desprende de los datos analizados, la probabilidad de fallecer antes de cumplir el año de vida es de más del 60%. Las razones para esta alta mortalidad infantil deberán buscarse en las condiciones sanitarias y nutricionales imperantes en la época y para este grupo social, considerando las enfermedades de mayor incidencia en los subadultos; también deben agregarse algunos casos de fallecimiento en los primeros días de vida por falta de desarrollo. En este grupo de edad las causas de muerte más comunes corresponden a las que pertenecen al sistema digestivo, respiratorio, infecciosas y en adultos a enfermedades cardiovasculares, cerebrales, etc.

  3. Turbine main engines

    CERN Document Server

    Main, John B; Herbert, C W; Bennett, A J S

    1965-01-01

    Turbine Main Engines deals with the principle of operation of turbine main engines. Topics covered include practical considerations that affect turbine design and efficiency; steam turbine rotors, blades, nozzles, and diaphragms; lubricating oil systems; and gas turbines for use with nuclear reactors. Gas turbines for naval boost propulsion, merchant ship propulsion, and naval main propulsion are also considered. This book is divided into three parts and begins with an overview of the basic mode of operation of the steam turbine engine and how it converts the pressure energy of the ingoing ste

  4. Maine highway safety plan

    Science.gov (United States)

    2010-01-01

    Each September 1, the MeBHS must provide NHTSA a comprehensive plan to reduce : traffic crashes and resulting deaths, injuries and property damage. The Highway Safety : Plan (HSP) serves as Maines application for available federal funds for these ...

  5. Maine Field Station

    Data.gov (United States)

    Federal Laboratory Consortium — In 2000 NOAA's National Marine Fisheries Service established the Maine Field Station in Orono, ME to have more direct involvement in the conservation of the living...

  6. Urban microbial ecology of a freshwater estuary of Lake Michigan.

    Science.gov (United States)

    Fisher, Jenny C; Newton, Ryan J; Dila, Deborah K; McLellan, Sandra L

    Freshwater estuaries throughout the Great Lakes region receive stormwater runoff and riverine inputs from heavily urbanized population centers. While human and animal feces contained in this runoff are often the focus of source tracking investigations, non-fecal bacterial loads from soil, aerosols, urban infrastructure, and other sources are also transported to estuaries and lakes. We quantified and characterized this non-fecal urban microbial component using bacterial 16S rRNA gene sequences from sewage, stormwater, rivers, harbor/estuary, and the lake surrounding Milwaukee, WI, USA. Bacterial communities from each of these environments had a distinctive composition, but some community members were shared among environments. We used a statistical biomarker discovery tool to identify the components of the microbial community that were most strongly associated with stormwater and sewage to describe an "urban microbial signature," and measured the presence and relative abundance of these organisms in the rivers, estuary, and lake. This urban signature increased in magnitude in the estuary and harbor with increasing rainfall levels, and was more apparent in lake samples with closest proximity to the Milwaukee estuary. The dominant bacterial taxa in the urban signature were Acinetobacter, Aeromonas , and Pseudomonas , which are organisms associated with pipe infrastructure and soil and not typically found in pelagic freshwater environments. These taxa were highly abundant in stormwater and sewage, but sewage also contained a high abundance of Arcobacter and Trichococcus that appeared in lower abundance in stormwater outfalls and in trace amounts in aquatic environments. Urban signature organisms comprised 1.7% of estuary and harbor communities under baseflow conditions, 3.5% after rain, and >10% after a combined sewer overflow. With predicted increases in urbanization across the Great Lakes, further alteration of freshwater communities is likely to occur with potential

  7. Urban microbial ecology of a freshwater estuary of Lake Michigan

    Directory of Open Access Journals (Sweden)

    Jenny C. Fisher

    2015-07-01

    Full Text Available Abstract Freshwater estuaries throughout the Great Lakes region receive stormwater runoff and riverine inputs from heavily urbanized population centers. While human and animal feces contained in this runoff are often the focus of source tracking investigations, non-fecal bacterial loads from soil, aerosols, urban infrastructure, and other sources are also transported to estuaries and lakes. We quantified and characterized this non-fecal urban microbial component using bacterial 16S rRNA gene sequences from sewage, stormwater, rivers, harbor/estuary, and the lake surrounding Milwaukee, WI, USA. Bacterial communities from each of these environments had a distinctive composition, but some community members were shared among environments. We used a statistical biomarker discovery tool to identify the components of the microbial community that were most strongly associated with stormwater and sewage to describe an “urban microbial signature,” and measured the presence and relative abundance of these organisms in the rivers, estuary, and lake. This urban signature increased in magnitude in the estuary and harbor with increasing rainfall levels, and was more apparent in lake samples with closest proximity to the Milwaukee estuary. The dominant bacterial taxa in the urban signature were Acinetobacter, Aeromonas, and Pseudomonas, which are organisms associated with pipe infrastructure and soil and not typically found in pelagic freshwater environments. These taxa were highly abundant in stormwater and sewage, but sewage also contained a high abundance of Arcobacter and Trichococcus that appeared in lower abundance in stormwater outfalls and in trace amounts in aquatic environments. Urban signature organisms comprised 1.7% of estuary and harbor communities under baseflow conditions, 3.5% after rain, and >10% after a combined sewer overflow. With predicted increases in urbanization across the Great Lakes, further alteration of freshwater communities is

  8. Urban microbial ecology of a freshwater estuary of Lake Michigan

    Science.gov (United States)

    Fisher, Jenny C.; Newton, Ryan J.; Dila, Deborah K.

    2015-01-01

    Freshwater estuaries throughout the Great Lakes region receive stormwater runoff and riverine inputs from heavily urbanized population centers. While human and animal feces contained in this runoff are often the focus of source tracking investigations, non-fecal bacterial loads from soil, aerosols, urban infrastructure, and other sources are also transported to estuaries and lakes. We quantified and characterized this non-fecal urban microbial component using bacterial 16S rRNA gene sequences from sewage, stormwater, rivers, harbor/estuary, and the lake surrounding Milwaukee, WI, USA. Bacterial communities from each of these environments had a distinctive composition, but some community members were shared among environments. We used a statistical biomarker discovery tool to identify the components of the microbial community that were most strongly associated with stormwater and sewage to describe an “urban microbial signature,” and measured the presence and relative abundance of these organisms in the rivers, estuary, and lake. This urban signature increased in magnitude in the estuary and harbor with increasing rainfall levels, and was more apparent in lake samples with closest proximity to the Milwaukee estuary. The dominant bacterial taxa in the urban signature were Acinetobacter, Aeromonas, and Pseudomonas, which are organisms associated with pipe infrastructure and soil and not typically found in pelagic freshwater environments. These taxa were highly abundant in stormwater and sewage, but sewage also contained a high abundance of Arcobacter and Trichococcus that appeared in lower abundance in stormwater outfalls and in trace amounts in aquatic environments. Urban signature organisms comprised 1.7% of estuary and harbor communities under baseflow conditions, 3.5% after rain, and >10% after a combined sewer overflow. With predicted increases in urbanization across the Great Lakes, further alteration of freshwater communities is likely to occur with

  9. Maine's forests 2008

    Science.gov (United States)

    George L. McCaskill; William H. McWilliams; Charles J. Barnett; Brett J. Butler; Mark A. Hatfield; Cassandra M. Kurtz; Randall S. Morin; W. Keith Moser; Charles H. Perry; Christopher W. Woodall

    2011-01-01

    The second annual inventory of Maine's forests was completed in 2008 after more than 3,160 forested plots were measured. Forest land occupies almost 17.7 million acres, which represents 82 percent of the total land area of Maine. The dominant forest-type groups are maple/beech/yellow birch, spruce/fir, white/red/jack pine, and aspen/white birch. Statewide volume...

  10. Maine Forests 2013

    Science.gov (United States)

    George L. McCaskill; Thomas Albright; Charles J. Barnett; Brett J. Butler; Susan J. Crocker; Cassandra M. Kurtz; William H. McWilliams; Patrick D. Miles; Randall S. Morin; Mark D. Nelson; Richard H. Widmann; Christopher W. Woodall

    2016-01-01

    The third 5-year annualized inventory of Maine's forests was completed in 2013 after more than 3170 forested plots were measured. Maine contains more than 17.6 million acres of forest land, an area that has been quite stable since 1960, covering more than 82 percent of the total land area. The number of live trees greater than 1 inch in diameter are approaching 24...

  11. Suspended sediment fluxes in a tropical estuary, west coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    AnilKumar, N.; DineshKumar, P.K.; Srinivas, K.

    Annual transport processes of suspended sediments in Beypore estuary - a tropical estuary along the south west coast of India - were investigated based on time series measurements within the system. It's observed that the sediment transport...

  12. A study of the probable movement and mixing of contaminants in a tidal estuary

    Digital Repository Service at National Institute of Oceanography (India)

    DineshKumar, P.K.; Sarma, R.V.

    The probable movement and mixing of contaminants within and through the Amba river estuary, a tidal estuary along the westcoast of India are studied Neutrally buoyant bipelane drogues, floats and dye were tracked at different stages of the tide...

  13. Bacterial domination over Archaea in ammonia oxidation in a monsoon-driven tropical estuary

    Digital Repository Service at National Institute of Oceanography (India)

    Vipindas, P.V.; Anas, A.; Jasmin, C.; Lallu, K.R.; Fausia, K.H.; Balachandran, K.K.; Muraleedharan, K.R.; Nair, S.

    Autotrophic ammonia oxidizing microorganisms,which are responsible for the rate-limiting step of nitrification in most aquatic systems, have not been studied in tropical estuaries. Cochin estuary (CE) is one of the largest, productive, and monsoon...

  14. Circulation and mixing process in Vasishta-Godavari estuary, east coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    Kumar, A.R.S.; Murty, T.V.R.; Rao, M.M.M.; Rao, V.R.; Reddy, B.S.R.

    Circulation and Mixing Process in Vasishta-Godavari Estuary, have been studied by using estuarine classification model. Analysis of salinity, salt budget, diffusion coefficients and flushing times based on salinity data of Vasishta-Godavari estuary...

  15. Picophytoplankton community in a tropical estuary: Detection of Prochlorococcus-like populations

    Digital Repository Service at National Institute of Oceanography (India)

    Mitbavkar, S.; Rajaneesh, K.M.; Anil, A.C.; Sundar, D.

    The influence of hydrography on the picophytoplankton (PP) abundance in estuaries was studied by sampling along a salinity gradient in an Indian estuary. Prochlorococcus-like cells were detected at salinities ranging from 0.06 to 35, which otherwise...

  16. Seasonal variations in abundance, biomass and grazing rates of microzooplankton in a tropical monsoonal estuary

    Digital Repository Service at National Institute of Oceanography (India)

    Gauns, M.; Mochemadkar, S.; Patil, S.; Pratihary, A.K.; Naqvi, S.W.A.; Madhupratap, M.

    Seasonal abundance, composition and grazing rates of microzooplankton (20–200 µm) in the Zuari estuary were investigated to evaluate their importance in food web dynamics of a tropical monsoonal estuary. Average abundances of microzooplankton...

  17. Impact of maintenance dredging on macrobenthic community structure of a tropical estuary

    Digital Repository Service at National Institute of Oceanography (India)

    Rehitha, T.V.; Ullas, N.; Vineetha, G.; Benny, P.Y.; Madhu, N.V.; Revichandran, C.

    This paper demonstrates the impact of maintenance dredging activities on the macrobenthic community structure of a tropical monsoonal estuary (Cochin estuary), located in the southwest coast of India for three consecutive years. The results...

  18. Maturation of the penaeid prawn Metapenaeus moyebi in Mandovi Estuary, Goa

    Digital Repository Service at National Institute of Oceanography (India)

    Nair, S.R.S.; Achuthankutty, C.T; Parulekar, A

    Metapenaeus moyebi contributed a good share of penaeid prawn population in the Mandovi Estuary of Goa, India throughout the year. Both males and females of this species with fully mature gonads were observed in the estuary, suggesting further...

  19. West Coast Estuaries for Groundfish Essential Fish Habitat (EFH) Environmental Impact Statement

    Data.gov (United States)

    Pacific States Marine Fisheries Commission — These data depict the boundaries of estuaries along the West Coast of the United States. The estuary boundaries are delineated according to the U.S. Fish and...

  20. EL CONSENTIMIENTO INFORMADO EN ODONTÓLOGOS RESIDENTES DE LA FACULTAD DE ODONTOLOGÍA DE LA UNIVERSIDAD NACIONAL DE LA PLATA O CONSENTIMENTO INFORMADO EM ODONTÓLOGOS RESIDENTES DA FACULDADE DE ODONTOLOGIA DA UNIVERSIDADE NACIONAL DE LA PLATA INFORMED CONSENT IN ODONTOLOGY RESIDENTS AT THE DENTISTRY FACULTY, LA PLATA'S NATIONAL UNIVERSITY

    Directory of Open Access Journals (Sweden)

    Ricardo Miguel

    2006-01-01

    Full Text Available Este trabajo se fundamenta en la necesidad de obtener datos sobre la práctica del consentimiento informado realizado por odontólogos. Los datos pertenecen al Programa de Residencias Odontológicas Universitarias (ROU de la Facultad de Odontología de la Universidad Nacional de La Plata (UNLP. La investigación tiene como intención conocer diferentes aspectos respecto a las fortalezas y debilidades de su utilización actual. A partir de los datos, se puede concluir que, a pesar de que los conocimientos teóricos sobre la práctica del consentimiento informado son escasos, existe una tendencia significativa a destinar tiempo en la consulta dental para su empleo, especialmente en la nueva generación. Se considera imperativo incluir en la malla curricular y en los programas académicos odontológicos principios éticos y legales en relación con el proceso de consentimiento informadoEste trabalho fundamenta a necessidade de se obter dados sobre a prática do consentimento informado realizado por odontólogos. Os dados pertencem ao Programa de Residencias Odontológicas Universitárias (ROU da Faculdade de Odontologia da Universidade Nacional de la Plata (UNLP. A pesquisa tem como objetivo conhecer os diferentes aspectos, a respeito das forças e fraquezas de sua utilzação atual. A partir dos dados, se pode concluir que, apesar de serem escassos os conhecimentos teóricos sobre a prática do consentimento informado, existe uma tendencia significativa a destinar tempo na consulta dental para seu uso, especialmente na nova geração. Considera-se um imperativo incluir no curriculo de formação profissional e nos programas acadêmicos odontológicos, princípios éticos e legais relacionados com o processo do consentimento informadoThis work is based upon the need to obtain data on the practice of informed consent carried out by dentists. Data was generated from the University Residence Program at the Dentistry Faculty, L.P.N.U., Argentina. The

  1. [Changes of wetland landscape pattern in Dayang River Estuary based on high-resolution remote sensing image].

    Science.gov (United States)

    Wu, Tao; Zhao, Dong-zhi; Zhang, Feng-shou; Wei, Bao-quan

    2011-07-01

    Based on the comprehensive consideration of the high resolution characteristics of remote sensing data and the current situation of land cover and land use in Dayang River Estuary wetland, a classification system with different resolutions of wetland landscape in the Estuary was established. The landscape pattern indices and landscape transition matrix were calculated by using the high resolution remote sensing data, and the dynamic changes of the landscape pattern from 1984 to 2008 were analyzed. In the study period, the wetland landscape components changed drastically. Wetland landscape transferred from natural wetland into artificial wetland, and wetland core regional area decreased. Natural wetland's largest patch area index descended, and the fragmentation degree ascended; while artificial wetland area expanded, its patch number decreased, polymerization degree increased, and the maximum patch area index had an obvious increasing trend. Increasing human activities, embankment construction, and reclamation for aquaculture were the main causes for the decrease of wetland area and the degradation of the ecological functions of Dayang River Estuary. To constitute long-term scientific and reasonable development plan, establish wetland nature reserves, protect riverway, draft strict inspective regimes for aquaculture reclamation, and energetically develop resource-based tourism industry would be the main strategies for the protection of the estuarine wetland.

  2. Sewage-induced disturbance on polychaetes inhabiting intertidal mussel beds of Brachidontes rodriguezii off Mar del Plata (SW Atlantic, Argentina.

    Directory of Open Access Journals (Sweden)

    Rodolfo Elías

    2006-12-01

    Full Text Available Continuous and short-term disturbances are produced on intertidal Brachidontes rodriguezii mussel beds by the sewage outfall of Mar del Plata, SW Atlantic. The effects on the associated polychaetes living on and between mussels were investigated, in both the spatial and short-term temporal scales. Multivariate methods show that the polychaete fauna was influenced by tidal level, total amount of sediment accumulated between mussels, distance from the sewage outfall, organic carbon of interstitial sediments, and sewage volume before and after the summer season. Environmental variables in the water column fitted with a spatial and temporal organic gradient. Capitella ‘capitata’ sp. showed typical opportunistic behaviour in relation to organic enrichment, as did Neanthes succinea, both being numerically dominant near the sewage discharge. Cirratulus sp., Caulleriella alata, and Boccardia polybranchia were common at intermediate distances from the outfall. Syllis prolixa, S. gracilis, and Protoariciella uncinata reached their highest abundance at intermediate stations and were characteristic of the control site. Close to the outfall mussel density and dominance is low, and opportunist polychaetes successfully colonize organically enriched interstitial sediments. At intermediate distances from the outfall sediments retained by mussels reach their maximum values, and density of polychaetes is also high. The control station is characterized by monolayered mussel beds and very low diversity of polychaetes. Opportunistic polychaetes increase in response to short-term increases of sewage discharge during the summer season (November-March.

  3. Raman Identification of Pigments in Wall Paintings of the Colonial Period from Bolivian Churches in the Ruta De La Plata

    Directory of Open Access Journals (Sweden)

    Carlos Rúa

    2018-03-01

    Full Text Available Micro-Raman spectroscopy was used to analyze and identify pigments and determine the palette of color in wall paintings from four churches of the Colonial Period, in the Bolivian highlands. The ancient churches Santiago de Callapa, Curahuara de Carangas, NuestraSeñora de Copacabana de Andamarca and San José de Soracachi were constructed during the 17th and 18th centuries, around the important colonial Ruta de la Plata, between Potosí city and Arica harbor on the Pacific coast of South America. Most pigments used in the wall paintings correspond to inorganic minerals as well as to organic colorants. Fully chlorinated copper phthalocyanine (green, copper phthalocyanine (blue, β-naphthol (yellow and benzoimidazolone (red, were identified in the corresponding colored areas suggesting subsequent recent interventions or restorations. Ground layer materials were also characterized. The present results allow for discussion of the pictorial techniques used in the Andean highland during the colonial period and allow conservators and restorers to make important decisions regarding the type of intervention to perform in the case of these important historical and patrimonial monuments.

  4. Immigration, science and health: risks control and expanding rights in the Rio de la Plata Basin (1873-1911

    Directory of Open Access Journals (Sweden)

    Fernanda Rebelo-Pinto

    2016-12-01

    Full Text Available This paper analyzes how immigration process in the Rio de Plata Basin countries, specifically Brazil and Argentina, promoted inflexions in the sanitations agreements in the end of 19th century. The port is a device within in which are defined knowledge and standards and are established interventions on people in transit, particularly immigrants. The barriers in the agreements between these countries were not only related to controversies within medical and scientific communities but also to political and economics tensions linked to the labor immigrants disputes. In the beginning of 20th century, we can see a shift of interest and issues related to public health: epidemic control was not enough. The states must guarantee some benefits to the populations, especially heath care. This new view is analyzed according to the understanding and uses of the liberal ideology concerning risk self-regulations, collectivization of welfare and expanding of civil and social rights. This process is leveraged in parts by the inclusion of the immigrants in theses societies.

  5. Arquitectura de sitios Web de bibliotecas universitarias: el sistema de bibliotecas de la Universidad Nacional de La Plata, Argentina

    Directory of Open Access Journals (Sweden)

    María Cecilia Corda

    2013-10-01

    Full Text Available Este trabajo descriptivo exploratorio se propone analizar la arquitectura de información (AI de sitios Web de bibliotecas de la Universidad Nacional de La Plata (UNLP, Argentina. Se analizaron 17 bibliotecas y se aplicó una grilla para recabar 10 aspectos relevantes. Los resultados fueron: 1. Ubicación del sitio Web de la biblioteca: 9 sitios incluidos en la página principal de la facultad. 2. Etiquetado de contenidos: terminología simple, sin jergas; no hay homogeneidad entre las bibliotecas. 3. Capacidad de búsqueda: 62% positiva, 38% negativa. 4. Sistema de búsqueda: simple 43%, compleja 10%, con ayudas 10%, ninguno 38%. 5. Sistemas de navegación: globales 5%, jerárquicos 79%, locales 5%, ninguno 11%. 6. Herramientas de navegación: barras 16%, frames o marcos 30%, índices 2%, mapas de sitio 7%, menús horizontales 9%, menús verticales 35%. 7. Sindicación de contenidos RSS: 3 sitios. 8. Otros servicios: chat 7%, descarga de documentos 16%, envío de formularios 14%, instructivos 21%, links a otras páginas 23%, tutoriales 5%, otros 14%. 9. Accesibilidad Web: 1 sitio. 10. Otras observaciones: ninguna. Se concluye que el desarrollo de los sitios es dispar y se recomienda considerar pautas de AI como parte de la cooperación en la red de bibliotecas de la UNLP.

  6. Proyecto integral de acondicionamiento de cuerpos momificados de la colección del Museo de La Plata

    Directory of Open Access Journals (Sweden)

    Reca, María Marta

    2009-01-01

    Full Text Available Con motivo de la decisión institucional de no exhibir restos humanos de procedencia americana, desde la Unidad de Conservación y Exhibición del Museo de La Plata se inició la delicada tarea de retirar las piezas de la sala de exhibición y acondicionar un espacio especial para el resguardo de la colección de cuerpos momificados. Dicha colección está conformada por veinte cuerpos en diferente estado de conservación y con características específicas. El presente estudio tiene por objeto dar cuenta de los procedimientos y las distintas etapas a considerar en un trabajo planificado y sistemático. En tal sentido, se explicitan, desde la conservación preventiva, los criterios que orientaron cada una de las etapas. El proyecto, en curso, contempla las instancias de evaluación, registro, tratamiento, definición de los contenedores y características del depósito.

  7. The educational policy field origins in Argentina: the case of Buenos Aires and La Plata Federal Universities

    Directory of Open Access Journals (Sweden)

    Julieta Susana Garcias Franco

    2014-07-01

    Full Text Available This paper presents partial results of an ongoing study whose objective is to map the approaches and theoretical trends in the educational policy theoretical field. More specifically, this study characterizes and describes the theoretical trends of the subject Educational Policy contents in the 50s of the last century in the Buenos Aires and La Plata Federal Universities. 46 programs were analyzed in the period 1917-1959, as well as the bibliography and theoretical background linked to the professors who were responsible for the subject. Surveying professors’ biographies, it was observed that in the period prior to the institutionalization of this field, the debate focused on the positivism or anti-positivism theoretical trends. Later on, the theoretical trends that permeated the programs from 1953 to 1954 had more distinct shades of positivism and anti-positivism than those of the beginning of the century, and three axes were observed: the national tradition, the pedagogical progressivism and the Spanish Krausism.

  8. Leishmania (Leishmania mexicana en el corregimiento de San Matías, municipio de Gómez Plata, Antioquia, Colombia

    Directory of Open Access Journals (Sweden)

    Diana Sierra

    2006-10-01

    Full Text Available Introducción. La leishmaniaisis es una enfermedad encontrada en focos naturales de infección donde están presentes insectos vectores y mamíferos reservorios deLeishmania. Objetivo. Registrar por primera vez la presencia de Leishmania (Leishmania mexicana Biagi, 1953, en el corregimiento de San Matías, municipio de Gómez Plata, departamento de Antioquia. Materiales y métodos. La especie fue aislada de un paciente con leishmaniasis cutánea localizada e identificada por la técnica de Inmunofluorescencia utilizando anticuerpos monoclonales específicos de especie y electroforesis de enzimas . Resultados y conclusión. Su perfil isoenzimático similar al de las cepas de referencia L. (L. mexicana (MNCY/BZ/62/M379 y L. (L. mexicana (MHOM/BE/82/BEL21, permitió concluír que la especie aislada del paciente es L. (L. mexicana.

  9. DNA barcode of Parodontidae species from the La Plata river basin - applying new data to clarify taxonomic problems

    Directory of Open Access Journals (Sweden)

    Elisangela Bellafronte

    Full Text Available In the past years, DNA barcoding has emerged as a quick, accurate and efficient tool to identify species. Considering the difficulty in identifying some Parodontidae species from the La Plata basin and the absence of molecular data for the group, we aimed to test the effectiveness of DNA barcoding and discuss the importance of using different approaches to solve taxonomic problems. Eight species were analyzed with partial sequences of Cytochrome c oxidase I. The mean intraspecific K2P genetic distance was 0.04% compared to 4.2% for mean interspecific K2P genetic distance. The analyses of distance showed two pairs of species with K2P genetic divergence lower than 2%, but enough to separate these species. Apareiodon sp. and A. ibitiensis, considered as the same species by some authors, showed 4.2% genetic divergence, reinforcing their are different species. Samples of A. affinis from the Uruguay and Paraguay rivers presented 0.3% genetic divergence, indicating a close relationship between them. However, these samples diverged 6.1% from the samples of the upper Paraná River, indicating that the latter represents a potentially new species. The results showed the effectiveness of the DNA barcoding method in identifying the analyzed species, which, together with the morphological and cytogenetic available data, help species identification.

  10. Historical economic and environmental policies influencing trace metal inputs in Montevideo Bay, Río de la Plata

    International Nuclear Information System (INIS)

    Bueno, C.; Brugnoli, E.; Figueira, R.C.L.; Muniz, P.; Ferreira, P.A.L.

    2016-01-01

    Montevideo Bay is located in the middle zone of the Rio de la Plata, and since the foundation of the city, several key economic and environmental policies affected the industry, and thus, metal inputs into this ecosystem. The aim of this study is to evaluate the sedimentary geochemical record of Montevideo Bay, in order to determine the historical inputs of anthropogenic metals to the system. In addition, environmental and economic policies of the country were taken into account to infer the relationship between them and the historic metal input. Concentrations of aluminum, chromium, copper, lead, scandium and zinc were analyzed and the EF and SPI indices were calculated. The analysis showed that since Montevideo foundation, metal concentrations increased in accordance with industry development, and the indices as well as the metal concentration represent a reliable footprint of the history of different economic and environmental policies influencing historical industrial activities. - Highlights: • Trace metal record of a sediment core of Montevideo Bay/harbor was studied. • The historic inputs of metals in the area were inferred. • System degradation evolved from anthropogenic impacts. • A relationship between pollution and environmental/economic policies was discussed.

  11. BIOLOGICAL FEATURES OF TARAN (RUTILUS HECKELII OF THE DNIEPER-BUG ESTUARY SYSTEM

    Directory of Open Access Journals (Sweden)

    K. Geina

    2016-03-01

    Full Text Available Purpose. To analyze morphological variability and basic biological features of the modern stock of taran of the Dnieper-Bug estuary system in the conditions of the transformed Dnieper flow. Methodology. Morphological variability was determined based on the comparison of morphological features of roach Rutilus rutilus (Linnaeus, 1758 of the Kakhovka reservoir and semi-migratory taran Rutilus rutilus heckelii (Nordmann, 1840 of the Dnieper-Bug estuary system. As a main criterion of the evaluation of the taran stock biological state, we used age, sex structure, growth characteristics, fecundity and condition factor. Fish sampling was carried out at stationary monitoring-observation stations of the Institute of Fisheries NAAS of Ukraine. Field and cameral processing of the collected materials were performed based on conventional methods and guidelines. Findings. Morphological variability analysis demonstrated significant differences between Dnieper and Bug taran. The highest differences were observed for antroventral distance (td=11.19. Significant differences were also observed for antenanal and ventroanal distances td=4.05-4.14. No significant differences were found for meristic features. There were also significant differences between Dnieper-Bug taran and Kakhovka reservoir roach, which had formed a resident form after regulating the Dnieper River flow. Kakhovka reservoir roach is more deep-bodied with Н=32.79%, t-test value was 5.65. Pelvic fins were more shifted to the caudal fin (td=5.28 that resulted in significant difference (p<0.05 in ventroanal distance (td=4.26. Taran also had somewhat smaller length of the anal fin base (td=4.73 but its height was higher – td=5.78. The main peculiarity of the current biological state of taran stock is the domination of young age groups. The small number of fish in the boundary groups of the age series right wing with relative stability of growth features indicate on intensive pressure on the

  12. Assessment of the Mutagenicity of Sediments from Yangtze River Estuary Using Salmonella Typhimurium/Microsome Assay

    Science.gov (United States)

    Liu, Li; Chen, Ling; Floehr, Tilman; Xiao, Hongxia; Bluhm, Kerstin; Hollert, Henner; Wu, Lingling

    2015-01-01

    Sediments in estuaries are of important environmental concern because they may act as pollution sinks and sources to the overlying water body. These sediments can be accumulated by benthic organisms. This study assessed the mutagenic potential of sediment extracts from the Yangtze River estuary by using the Ames fluctuation assay with the Salmonella typhimurium his (−) strain TA98 (frameshift mutagen indicator) and TA100 (baseshift mutagen indicator). Most of the sediment samples were mutagenic to the strain TA98, regardless of the presence or absence of exogenous metabolic activation (S9 induction by β-naphthoflavone/phenobarbital). However, none of the samples were mutagenic to the strain TA100. Thus, the mutagenicity pattern was mainly frameshift mutation, and the responsible toxicants were both direct (without S9 mix) and indirect (with S9 mix) mutagens. The mutagenicity of the sediment extracts increased when S9 was added. Chemical analysis showed a poor correlation between the content of priority polycyclic aromatic hydrocarbons and the detected mutagenicity in each sample. The concept of effect-directed analysis was used to analyze possible compounds responsible for the detected mutagenic effects. With regard to the mutagenicity of sediment fractions, non-polar compounds as well as weakly and moderately polar compounds played a main role. Further investigations should be conducted to identify the responsible components. PMID:26606056

  13. Organochlorine pesticides in surface sediments and suspended particulate matters from the Yangtze estuary, China

    International Nuclear Information System (INIS)

    Liu Min; Cheng Shubo; Ou Dongni; Yang Yi; Liu Hualin; Hou Lijun; Gao Lei; Xu Shiyuan

    2008-01-01

    Total HCHs' and total DDTs' levels in surface sediments (SS) ranged from 0.5 to 17.5 ng g -1 and from 0.9 to 33.1 ng g -1 , averaged 6.0 and 8.2 ng g -1 , respectively. Total HCHs' and total DDTs' levels in suspended particulate matters (SPM) varied from 6.2 to 14.8 ng g -1 with a mean value of 12.3 ng g -1 and were from 3.4 to 25.7 ng g -1 with an average of 16.4 ng g -1 , respectively. Lindane is the main HCHs' source and continuing use in the Yangtze Delta areas of 'pure' γ-HCH (lindane) rather than technical HCH (a mix of largely α- and some γ-HCH). DDTs in SS are mainly accumulated in history. However, high DDT fractions in SPM are indicators of new input of typical dicofol type DDT from 2002 to 2004. It can be seen that most samples from the Yangtze estuary were in ranges where adverse biological effects are expected, either occasionally or frequently. - SPM, more polluted than SS, had similar contaminant composition. New input of lindane and typical dicofol type DDT were found and Yangtze estuary had been affected adversely

  14. Impact of climate variability on ichthyoplankton communities: An example of a small temperate estuary

    Science.gov (United States)

    Primo, Ana Lígia; Azeiteiro, Ulisses Miranda; Marques, Sónia Cotrim; Pardal, Miguel Ângelo

    2011-03-01

    Recent variations in the precipitation regime across southern Europe have led to changes in river fluxes and salinity gradients affecting biological communities in most rivers and estuaries. A sampling programme was developed in the Mondego estuary, Portugal, from January 2003 to December 2008 at five distinct sampling stations to evaluate spatial, seasonal and inter-annual distributions of fish larvae. Gobiidae was the most abundant family representing 80% of total catch and Pomatoschistus spp. was the most important taxon. The fish larval community presented a clear seasonality with higher abundances and diversities during spring and summer seasons. Multivariate analysis reinforced differences among seasons but not between years or sampling stations. The taxa Atherina presbyter, Solea solea, Syngnathus abaster, Crystallogobius linearis and Platichthys flesus were more abundant during spring/summer period while Ammodytes tobianus, Callionymus sp., Echiichthys vipera and Liza ramada were more abundant in autumn/winter. Temperature, chlorophyll a and river flow were the main variation drivers observed although extreme drought events (year 2005) seemed not to affect ichthyoplankton community structure. Main changes were related to a spatial displacement of salinity gradient along the estuarine system which produced changes in marine species distribution.

  15. Organochlorine pesticides in surface sediments and suspended particulate matters from the Yangtze estuary, China

    Energy Technology Data Exchange (ETDEWEB)

    Liu Min [Department of Geography, Key Laboratory of Geographical Information Sciences of the State Ministry of Education, East China Normal University, Shanghai 200062 (China)], E-mail: mliu@geo.ecnu.edu.cn; Cheng Shubo; Ou Dongni [Department of Geography, Key Laboratory of Geographical Information Sciences of the State Ministry of Education, East China Normal University, Shanghai 200062 (China); Yang Yi [Vienna University, Department of Environmental Geoscience (Austria); Liu Hualin [Department of Geography, Key Laboratory of Geographical Information Sciences of the State Ministry of Education, East China Normal University, Shanghai 200062 (China); Hou Lijun [State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai 200062 (China); Gao Lei; Xu Shiyuan [Department of Geography, Key Laboratory of Geographical Information Sciences of the State Ministry of Education, East China Normal University, Shanghai 200062 (China)

    2008-11-15

    Total HCHs' and total DDTs' levels in surface sediments (SS) ranged from 0.5 to 17.5 ng g{sup -1} and from 0.9 to 33.1 ng g{sup -1}, averaged 6.0 and 8.2 ng g{sup -1}, respectively. Total HCHs' and total DDTs' levels in suspended particulate matters (SPM) varied from 6.2 to 14.8 ng g{sup -1} with a mean value of 12.3 ng g{sup -1} and were from 3.4 to 25.7 ng g{sup -1} with an average of 16.4 ng g{sup -1}, respectively. Lindane is the main HCHs' source and continuing use in the Yangtze Delta areas of 'pure' {gamma}-HCH (lindane) rather than technical HCH (a mix of largely {alpha}- and some {gamma}-HCH). DDTs in SS are mainly accumulated in history. However, high DDT fractions in SPM are indicators of new input of typical dicofol type DDT from 2002 to 2004. It can be seen that most samples from the Yangtze estuary were in ranges where adverse biological effects are expected, either occasionally or frequently. - SPM, more polluted than SS, had similar contaminant composition. New input of lindane and typical dicofol type DDT were found and Yangtze estuary had been affected adversely.

  16. Riverbed Micromorphology of the Yangtze River Estuary, China

    Directory of Open Access Journals (Sweden)

    Shuaihu Wu

    2016-05-01

    Full Text Available Dunes are present in nearly all fluvial channels and are vital in understanding sediment transport, deposition, and flow conditions during floods of rivers and estuaries. This information is pertinent for helping developing management practices to reduce risks in river transportation and engineering. Although a few recent studies have investigated the micromorphology of a portion of the Yangtze River estuary in China, our understanding of dune development in this large estuary is incomplete. It is also poorly understood how the development and characteristics of these dunes have been associated with human activities in the upper reach of the Yangtze River and two large-scale engineering projects in the estuarine zone. This study analyzed the feature in micromorphology of the entire Yangtze River estuary bed over the past three years and assessed the morphological response of the dunes to recent human activities. In 2012, 2014, and 2015, multi-beam bathymetric measurements were conducted on the channel surface of the Yangtze River estuary. The images were analyzed to characterize the subaqueous dunes and detect their changes over time. Bottom sediment samples were collected for grain size analysis to assess the physical properties of the dunes. We found that dunes in the Yangtze River estuary can be classified in four major classes: very large dunes, large dunes, medium dunes, and small dunes. Large dunes were predominant, amounting to 51.5%. There was a large area of dunes developed in the middle and upper reaches of the Yangtze River estuary and in the Hengsha Passage. A small area of dunes was observed for the first time in the turbidity maximum zone of the Yangtze River estuary. These dunes varied from 0.12 to 3.12 m in height with a wide range of wavelength from 2.83 to 127.89 m, yielding a range in height to wavelength of 0.003–0.136. Sharp leeside slope angles suggest that the steep slopes of asymmetrical dunes in the middle and upper

  17. Silicon dynamics in the Oder estuary, Baltic Sea

    Science.gov (United States)

    Pastuszak, Marianna; Conley, Daniel J.; Humborg, Christoph; Witek, Zbigniew; Sitek, Stanisław

    2008-10-01

    Studies on dissolved silicate (DSi) and biogenic silica (BSi) dynamics were carried out in the Oder estuary, Baltic Sea in 2000-2005. The Oder estuary proved to be an important component of the Oder River-Baltic Sea continuum where very intensive seasonal DSi uptake during spring and autumn, but also BSi regeneration during summer take place. Owing to the regeneration process annual DSi patterns in the river and the estuary distinctly differed; the annual patterns of DSi in the estuary showed two maxima and two minima in contrast to one maximum- and one minimum-pattern in the Oder River. DSi concentrations in the river and in the estuary were highest in winter (200-250 μmol dm - 3 ) and lowest (often less than 1 μmol dm - 3 ) in spring, concomitant with diatom growth; such low values are known to be limiting for new diatom growth. Secondary DSi summer peaks at the estuary exit exceeded 100 μmol dm - 3 , and these maxima were followed by autumn minima coinciding with the autumn diatom bloom. Seasonal peaks in BSi concentrations (ca. 100 μmol dm - 3 ) occurred during the spring diatom bloom in the Oder River. Mass balance calculations of DSi and BSi showed that DSi + BSi import to the estuary over a two year period was 103.2 kt and that can be compared with the DSi export of 98.5 kt. The difference between these numbers gives room for ca. 2.5 kt BSi to be annually exported to the Baltic Sea. Sediment cores studies point to BSi annual accumulation on the level of 2.5 kt BSi. BSi import to the estuary is on the level of ca. 10.5 kt, thus ca. 5 kt of BSi is annually converted into the DSi, increasing the pool of DSi that leaves the system. BSi concentrations being ca. 2 times higher at the estuary entrance than at its exit remain in a good agreement with the DSi and BSi budgeting presented in the paper.

  18. Main sequence mass loss

    International Nuclear Information System (INIS)

    Brunish, W.M.; Guzik, J.A.; Willson, L.A.; Bowen, G.

    1987-01-01

    It has been hypothesized that variable stars may experience mass loss, driven, at least in part, by oscillations. The class of stars we are discussing here are the δ Scuti variables. These are variable stars with masses between about 1.2 and 2.25 M/sub θ/, lying on or very near the main sequence. According to this theory, high rotation rates enhance the rate of mass loss, so main sequence stars born in this mass range would have a range of mass loss rates, depending on their initial rotation velocity and the amplitude of the oscillations. The stars would evolve rapidly down the main sequence until (at about 1.25 M/sub θ/) a surface convection zone began to form. The presence of this convective region would slow the rotation, perhaps allowing magnetic braking to occur, and thus sharply reduce the mass loss rate. 7 refs

  19. Functional diversity of fish in estuaries at a global extent

    Directory of Open Access Journals (Sweden)

    Rita P Vasconcelos

    2015-10-01

    Full Text Available Biodiversity is currently viewed as a framework encompassing multiple facets of the variety of life, including taxonomic and functional aspects. Species richness and composition of fish assemblages in estuaries is defined by global to local processes acting on community colonization. The present study further investigates how biodiversity of fish assemblages varies among estuaries globally, by simultaneously analysing taxonomic and functional richness and diversity of assemblages. A comprehensive worldwide database was compiled on the fish assemblage composition and environmental characteristics of estuaries. In addition, functional attributes of the fish species were characterized such as body size, habitat use and trophic ecology. We investigated the relationship between taxonomic and functional aspects of biodiversity, i.e. the match or mismatch between the two. We also explored how functional diversity of fish assemblages varied among estuaries globally and related to environmental features of estuaries, i.e. historic and contemporary, global and local constraints. The results are explored in the context of ecosystem functioning and resilience, and outcomes relevant to assist in prioritizing conservation efforts are highlighted.

  20. Seasonal mercury concentrations and {delta}{sup 15}N and {delta}{sup 13}C values of benthic macroinvertebrates and sediments from a historically polluted estuary in south central Chile

    Energy Technology Data Exchange (ETDEWEB)

    Diaz-Jaramillo, Mauricio, E-mail: mdiazjaramillo@conicet.gov.ar [Aquatic Systems Research Unit, EULA Chile Environmental Sciences Centre, Universidad de Concepcion (Chile); Munoz, Claudia; Rudolph, Ignacio [Aquatic Systems Research Unit, EULA Chile Environmental Sciences Centre, Universidad de Concepcion (Chile); Servos, Mark [Department of Biology, University of Waterloo, ON (Canada); Barra, Ricardo [Aquatic Systems Research Unit, EULA Chile Environmental Sciences Centre, Universidad de Concepcion (Chile)

    2013-01-01

    The Lenga Estuary is one of the most industrialized sites in south central Chile where the historic operation of chlor-alkali plants resulted in large quantities of mercury (Hg) being deposited into the estuary. This historical contamination may still represent a risk to the biota in the estuary. To investigate this four macroinvertebrates, Neotrypaea uncinata (ghostshrimp), Elminius kingii (barnacle), Hemigrapsus crenulatus (shore crab) and Perinereis gualpensis (ragworm) were collected seasonally from three different sites in the Lenga Estuary and one in a reference estuary (Tubul Estuary), and analyzed for Hg and stable isotopes ({delta}{sup 15}N and {delta}{sup 13}C). Mercury concentrations in Lenga sediments ranged from 0.4 {+-} 0.1 to 13 {+-} 3 mg/kg, while those in Tubul sediments ranged from 0.02 {+-} 0.01 to 0.07 {+-} 0.09 mg/kg. Total Hg concentrations of invertebrates were significantly different between estuaries (p < 0.05), but not by species or season for each estuary (p > 0.05). In contrast, organic Hg concentrations were different by species and season with shore crab muscle tissues exhibiting the greatest percent difference. Site-specific relationships demonstrated that total Hg concentrations in ragworm best reflected the total Hg sediment mercury concentrations. Signatures of {delta}{sup 13}C were correlated to the organic Hg % rather than total Hg. This suggests that organic Hg concentrations in these species were related to the carbon sources. -- Highlights: Black-Right-Pointing-Pointer Hg in sediments and biota from Lenga Estuary were elevated compared to nearby estuary. Black-Right-Pointing-Pointer Invertebrates showed interspecific and seasonal differences in terms of organic Hg %. Black-Right-Pointing-Pointer Total Hg levels in the ragworm best reflect Hg sediment gradient in Lenga Estuary. Black-Right-Pointing-Pointer Interspecific variation in {delta}{sup 13}C signatures indicated different feeding modes. Black

  1. 76 FR 23306 - Takes of Marine Mammals Incidental to Specified Activities; Russian River Estuary Management...

    Science.gov (United States)

    2011-04-26

    ... Marine Mammals Incidental to Specified Activities; Russian River Estuary Management Activities AGENCY...) to incidentally harass, by Level B harassment only, three species of marine mammals during estuary... December 31, 2010; and Russian River Estuary Outlet Channel Adaptive Management Plan. NMFS' Environmental...

  2. 77 FR 24471 - Takes of Marine Mammals Incidental to Specified Activities; Russian River Estuary Management...

    Science.gov (United States)

    2012-04-24

    ... Marine Mammals Incidental to Specified Activities; Russian River Estuary Management Activities AGENCY...) to incidentally harass, by Level B harassment only, three species of marine mammals during estuary... Estuary Outlet Channel Adaptive Management Plan; and Feasibility of Alternatives to the Goat Rock State...

  3. 33 CFR 165.1190 - Security Zone; San Francisco Bay, Oakland Estuary, Alameda, CA.

    Science.gov (United States)

    2010-07-01

    ..., Oakland Estuary, Alameda, CA. 165.1190 Section 165.1190 Navigation and Navigable Waters COAST GUARD... § 165.1190 Security Zone; San Francisco Bay, Oakland Estuary, Alameda, CA. (a) Location. The following area is a security zone: All navigable waters of the Oakland Estuary, California, from the surface to...

  4. 78 FR 68995 - Safety Zone: Vessel Removal From the Oakland Estuary, Alameda, CA

    Science.gov (United States)

    2013-11-18

    ...-AA00 Safety Zone: Vessel Removal From the Oakland Estuary, Alameda, CA AGENCY: Coast Guard, DHS. ACTION... waters of the Oakland Estuary just north of the Park Street Bridge in Alameda, CA in support of the Oakland Estuary Closure for the Vessel Removal Project on November 4, 2013 through November 22, 2013. This...

  5. 78 FR 46332 - Proposed Information Collection Request; Comment Request; National Estuary Program

    Science.gov (United States)

    2013-07-31

    ... Request; Comment Request; National Estuary Program AGENCY: Environmental Protection Agency (EPA). ACTION... request (ICR), ``National Estuary Program'' (EPA ICR No. 1500.08, OMB Control No. 2040-0138 to the Office... comments to OMB. Abstract: The National Estuary Program (NEP) involves collecting information from the...

  6. Eco-morphological problems in the Yangtze Estuary and the Western Scheldt

    NARCIS (Netherlands)

    De Vriend, H.J.; Wang, Z.B.; Ysebaert, T.; Herman, P.M.J.; Ding, P.X.

    2011-01-01

    This paper compares the Yangtze Estuary in China and the Western Scheldt Estuary in The Netherlands by their morphodynamic and ecological systems, their engineering works and estuarine management issues, and the major challenges in studying them. Physically speaking, the two estuaries are very

  7. Variability in stratification and flushing times of the Gautami-Godavari estuary, India

    Digital Repository Service at National Institute of Oceanography (India)

    Sridevi, B.; Sarma, V.V.S.S.; Murty, T.V.R.; Sadhuram, Y.; Reddy, N.P.C.; Vijaykumar, K.; Raju, N.S.N.; JawaharKumar, CH.; Raju, Y.S.N.; Luis, R.; Kumar, M.D.; Prasad, K.V.S.R.

    –Godavari estuary (G–GE) during spring and neap tide periods covering entire spectrum of discharge over a distance of 36 km from the mouth. The bathymetry of the estuary was recently changed due to dredging of ~20 km of the estuary from the mouth for transportation...

  8. 75 FR 2517 - Notice of Solicitation for Estuary Habitat Restoration Program

    Science.gov (United States)

    2010-01-15

    ..., wastewater treatment plant upgrades, combined sewer outfalls, and non-point source pollution projects such as... Estuary Restoration Act of 2000, Title I of the Estuaries and Clean Waters Act of 2000 (Pub. L. 106-457... with fresh water from land drainage.'' Estuary also includes the ``* * * near coastal waters and...

  9. Spatial and temporal patterns in the hyperbenthic community structure in a warm temperate southern African permanently open estuary

    Science.gov (United States)

    Heyns, Elodie; Froneman, William

    2010-06-01

    The spatial and temporal patterns in the hyperbenthic community structure (>500 μm) in the warm temperate, permanently open Kariega Estuary situated along the south-eastern coastline of South Africa was investigated monthly over a period of twelve months. Data were collected using a modified hyperbenthic sledge at six stations along the length of the estuary. Physico-chemical data indicate the presence of a constant reverse salinity gradient, with highest salinities measured in the upper reaches and lowest at the mouth of the estuary. Strong seasonal patterns in temperature, dissolved oxygen and total chlorophyll- a (chl- a) concentration were evident. Total average hyperbenthic densities ranged between 0.4 and 166 ind.m -3 in the lower net and between 0.2 and 225 ind.m -3 in the upper net. Hyperbenthic biomass values ranged between 0.02 and 11.9 mg.dry weight.m -3 in the lower net and between 0.02 and 17.4 mg.dry weight.m -3 in the upper net. Both the lower and upper nets were numerically dominated by decapods (mainly brachyuran crab zoea) with the exception of June and July 2008 when mysids (mainly Mesopodopsis wooldridgei) dominated, comprising up to 72.4 ± 58.14% of the total abundance in the lower net. A redundancy analysis (RDA) indicated that 99.2% of the variance in the hyperbenthic community structure could be explained by the first two canonical axes. Axis one, which accounted for 96.8% of the total variation detected in the ordination plot was highly correlated with sedimentary organic content and to a lesser extent the chl- a concentration within the Kariega Estuary. The correlations with the second canonical axis (2.4%) were less obvious, however, salinity and seston concentration were weakly correlated with this axis.

  10. The role of the smooth cordgrass Spartina alterniflora and associated sediments in the heavy metal biogeochemical cycle within Bahia Blanca estuary salt marshes

    Energy Technology Data Exchange (ETDEWEB)

    Hempel, M. [Dept. of Environmental Process Engineering, International Graduate School Zittau, Zittau (Germany); Botte, S.E. [Area de Oceanografia Quimica, Inst. Argentino de Oceanografia (IADO), CCT-CONICET, Bahia Blanca (Argentina); Dept. de Biologia, Bioquimica y Farmacia (DBBF), Univ. Nacional del Sur (UNS), Bahia Blanca (Argentina); Negrin, V.L.; Chiarello, M.N. [Area de Oceanografia Quimica, Inst. Argentino de Oceanografia (IADO), CCT-CONICET, Bahia Blanca (Argentina); Marcovecchio, J.E. [Area de Oceanografia Quimica, Inst. Argentino de Oceanografia (IADO), CCT-CONICET, Bahia Blanca (Argentina); Facultad Regional Bahia Blanca (UTN-FRBB), Univ. Tecnologica Nacional, Bahia Blanca (Argentina); Univ. FASTA, Mar del Plata (Argentina)

    2008-10-15

    Background, aim, and scope Bahia Blanca estuary is characterized by the occurrence of large intertidal areas, including both naked tidal flats and salt marshes densely vegetated with Spartina alterniflora. The estuary is strongly affected by human activities, including industrial and municipal discharges, harbor maintenance, cargo vessels and boat navigation, oil storage and processing, etc. Even numerous studies have reported the occurrence and distribution of heavy metals in sediments and biota from this estuary, although the function of the halophyte vegetation on metals distribution was at present not studied. The main objective of the present study was to understand the potential role of the salt marshes as a sink or source of metals to the estuary, considering both the obtained data on metal levels within sediments and plants from the studied areas at naked tidal as well as vegetated flats. Conclusions and recommendations Considering the comments on the previous paragraphs, salt marshes from Bahia Blanca estuary are sources or sinks for metals? It can be sustained that both are the case, even if it is often stated that wetlands serve as sinks for pollutants, reducing contamination of surrounding ecosystems (Weis and Weis, Environ Int 30:685-700, 2004). In the present study case, the sediments (which tend to be anoxic and reduced) act as sinks, while the salt marshes can become a source of metal contaminants. This is very important for this system because the macrophytes have been shown to retain the majority of metals in the underground tissues, and particularly in their associated sediments. This fact agreed well with previous reports, such as that from Leendertse et al., (Environ Pollut 94:19-29, 1996) who found that about 50% of the absorbed metals were retained in salt marshes and 50% was exported. Thus, keeping in mind the large spreading of S. alterniflora salt marshes within Bahia Blanca estuary, it must be carefully considered as a redistributor of

  11. Species-specific variation in the phosphorus nutritional sources by microphytoplankton in a Mediterranean estuary

    Directory of Open Access Journals (Sweden)

    MARLY CAROLINA MARTINEZ SOTO

    2015-08-01

    Full Text Available We investigated the species-specific phosphorus (P nutrition sources in the microphytoplankton community in the Mahon estuary (Minorca, Western Mediterranean in 2011, under two contrasting hydrographic scenarios. Estuarine flow, nutrient concentrations, phytoplankton community composition and enzyme-labeled fluorescence (ELF were measured in June and October, corresponding to the beginning and the end of summer. Dissolved inorganic nitrogen (DIN and inorganic phosphate (Pi exhibited enhanced concentrations in the inner estuary where N:P molar ratios suggested P-limitation in both surveys. Pi was low and variable (0.09±0.02 μmol•l-1 in June and 0.06±0.02 μmol•l-1 in October, whereas organic phosphorus remained a more reliable P source. Even though ambient Pi concentrations were slightly higher on June, when the microphytoplankton assemblage was dominated by dinoflagellates, the percentage of cells expressing ELF labeling was notably higher (65% of total cells than in October (12%, when the presence of diatoms characterized the microphytoplankton community. ELF was mainly expressed by dinoflagellate taxa, whereas diatoms only expressed significant AP in the inner estuary during the June survey. A P-addition bioassay in which response of AP to Pi enrichment was evaluated showed remarkable reduction in AP with increasing Pi. However, some dinoflagellate species maintained AP even when Pi was supplied in excess. We suggest that in the case of some dinoflagellate species AP is not as tightly controlled by ambient Pi as previously believed. AP activity in these species could indicate selective use of organic phosphorus, or slow metabolic response to changes in P forms, rather than physiological stress to low Pi availability. We emphasize the importance of identifying the links between the different P sources and the species-specific requirements, in order to understand the ecological response to anthropogenic biogeochemical perturbations.

  12. FERMILAB: Main Injector

    International Nuclear Information System (INIS)

    Anon.

    1993-01-01

    The Fermilab Main Injector (FMI) project is the centerpiece of the Laboratory's Fermilab III programme for the 1990s. Designed to support a luminosity of at least 5x10 31 cm -2 s -1 in the Tevatron collider, it will also provide new capabilities for rare neutral kaon decay and neutrino oscillation studies. The Fermilab Main Injector 8-150 GeV synchrotron is designed to replace the existing Main Ring which seriously limits beam intensities for the Tevatron and the antiproton production target. The project has passed several significant milestones and is now proceeding rapidly towards construction. The project received a $11.65M appropriation in 1992 and has been given $15M for the current fiscal year. Through the Energy Systems Acquisition Advisory Board (ESAAB) process, the US Department of Energy (DoE) has authorized funds for construction of the underground enclosure and service building where the Main Injector will touch the Tevatron, and to the preparation of bids for remaining project construction

  13. FERMILAB: Main Injector

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    1993-06-15

    The Fermilab Main Injector (FMI) project is the centerpiece of the Laboratory's Fermilab III programme for the 1990s. Designed to support a luminosity of at least 5x10{sup 31} cm{sup -2} s{sup -1} in the Tevatron collider, it will also provide new capabilities for rare neutral kaon decay and neutrino oscillation studies. The Fermilab Main Injector 8-150 GeV synchrotron is designed to replace the existing Main Ring which seriously limits beam intensities for the Tevatron and the antiproton production target. The project has passed several significant milestones and is now proceeding rapidly towards construction. The project received a $11.65M appropriation in 1992 and has been given $15M for the current fiscal year. Through the Energy Systems Acquisition Advisory Board (ESAAB) process, the US Department of Energy (DoE) has authorized funds for construction of the underground enclosure and service building where the Main Injector will touch the Tevatron, and to the preparation of bids for remaining project construction.

  14. Main facts 1995

    International Nuclear Information System (INIS)

    1996-01-01

    This report presents the main facts of the studies carried out by the Direction des Etudes et Recherches (DER) of Electricite de France: new applications of electricity, classical and nuclear thermal power plants, electrical equipment, environment protection, monitoring and plants operations

  15. Main designations and attributions

    International Nuclear Information System (INIS)

    2010-01-01

    The chapter presents the main designations and attributions of the LNMRI - Brazilian National Laboratory of Metrology of Ionizing Radiation, the Cooperative Center in Radiation Protection and Medical Preparations for Accidents with Radiation; the Treaty for fully banning of nuclear tests and the Regional Center for Training of IAEA

  16. Maine Bouguer Gravity Grid

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A 2 kilometer Bouguer anomaly grid for the state of Maine. Number of columns is 197 and number of rows is 292. The order of the data is from the lower left to the...

  17. Main facts 1993

    International Nuclear Information System (INIS)

    1994-01-01

    This report presents the main facts of the studies carried out by the Direction des Etudes et Recherches (DER) of Electricite de France: new applications of electricity, classical and nuclear thermal power plants, electrical equipment, environment protection, network analysis, information and informatic equipment

  18. Delaware Estuary situation reports. Emergency response: How do emergency management officials address disasters in the Delaware Estuary

    International Nuclear Information System (INIS)

    Sylves, R.T.

    1991-01-01

    From hurricanes and other natural threats to oil spills and other manmade emergencies, the Delaware Estuary has experienced a variety of disasters over the years. The toll that these events take on the estuary and those who live on its shores depends largely upon the degree of emergency preparedness, speed of response, and effectiveness of recovery operations. In Emergency Response: How Do Emergency Management Officials Address Disasters in the Delaware Estuary, the latest addition to its Delaware Estuary Situation Report series, the University of Delaware Sea Grant College Program defines emergency management; examines the roles that the Coast Guard, Army Corps of Engineers, and Environmental Protection Agency play in an emergency; and reviews how each of these federal agencies operated during an actual disaster--the 1985 Grand Eagle oil spill. The report was written by Dr. Richard T. Sylves, a professor of political science at the University of Delaware. Sylves has been studying emergency management for the past 15 years, with special emphasis on oil spill preparedness and response in the Mid-Atlantic Region. The Delaware Estuary Situation Report is 12 pages long and contains maps and photographs, as well as a detailed account of response and recovery operations undertaken during the Grand Eagle oil spill. A comparison of the 1985 Grand Eagle spill and the 1989 Presidente Rivera spill also is included

  19. Effects of heavy metal contamination on the macrobenthic fauna in estuaries: The case of the Seine estuary

    International Nuclear Information System (INIS)

    Dauvin, Jean-Claude

    2008-01-01

    Heavy metal contamination levels are generally higher in estuaries than in the open sea. Some estuaries, the Seine estuary for example, have particularly high pollution levels of metals, yet continue to support a very high benthic biomass and remain quite productive. Measurements of sediment contamination are highly variable due to diverse chemical analysis methods, sediments origin and sources of contaminants found in the estuaries. Salinity appears to be the principal factor controlling contaminant distribution in the sediment and the overlying and/or interstitial waters; it also affects the bioavailability of contaminants in estuarine sediments. Of course, the response to contaminants varies greatly among species and assemblages. Trace metals explain only a small part of the variation in benthic community structure. Some species, such as the shrimp Crangon crangon, appears vulnerable to metal pollution, while other species, such as Scrobicularia plana, are able to tolerate quite high levels of cadmium in their tissue. This paper demonstrates the wide variability of benthic responses to contamination, which is probably due to the high spatio-temporal heterogeneity of the estuary. To reduce the problems due the heterogeneity and variability observed to date in the available results, it will be necessary to encourage integrated estuarine studies, in which sedimentologists, chemists, and biologists work together on the same campaigns at the same sites

  20. Hydrologic data summary for the St. Lucie River Estuary, Martin and St. Lucie Counties, Florida, 1998-2001

    Science.gov (United States)

    Byrne, Michael J.; Patino, Eduardo

    2004-01-01

    A hydrologic analysis was made at three canal sites and four tidal sites along the St. Lucie River Estuary in southeastern Florida from 1998 to 2001. The data included for analysis are stage, 15-minute flow, salinity, water temperature, turbidity, and suspended-solids concentration. During the period of record, the estuary experienced a drought, major storm events, and high-water discharge from Lake Okeechobee. Flow mainly occurred through the South Fork of the St. Lucie River; however, when flow increased through control structures along the C-23 and C-24 Canals, the North Fork was a larger than usual contributor of total freshwater inflow to the estuary. At one tidal site (Steele Point), the majority of flow was southward toward the St. Lucie Inlet; at a second tidal site (Indian River Bridge), the majority of flow was northward into the Indian River Lagoon. Large-volume stormwater discharge events greatly affected the St. Lucie River Estuary. Increased discharge typically was accompanied by salinity decreases that resulted in water becoming and remaining fresh throughout the estuary until the discharge events ended. Salinity in the estuary usually returned to prestorm levels within a few days after the events. Turbidity decreased and salinity began to increase almost immediately when the gates at the control structures closed. Salinity ranged from less than 1 to greater than 35 parts per thousand during the period of record (1998-2001), and typically varied by several parts per thousand during a tidal cycle. Suspended-solids concentrations were observed at one canal site (S-80) and two tidal sites (Speedy Point and Steele Point) during a discharge event in April and May 2000. Results suggest that most deposition of suspended-solids concentration occurs between S-80 and Speedy Point. The turbidity data collected also support this interpretation. The ratio of inorganic to organic suspended-solids concentration observed at S-80, Speedy Point, and Steele Point

  1. Tritium in the Savannah River Estuary and adjacent marine waters

    International Nuclear Information System (INIS)

    Hayes, D.W.

    1978-01-01

    The tritium distribution in the Savannah River estuary and adjacent marine waters was measured to provide information on the dilution, mixing, and movement of Savannah River water in this region. The Savannah River marine region was chosen because the average tritium concentration in this river is 5 pCi/ml, whereas other rivers in the southeastern United States average less than 0.5 pCi/ml. The increased tritium concentration in the Savannah River is due to releases from the Savannah River Plant of the Department of Energy. Tritium measurements have proved particularly effective in estimating the flushing time of the Savannah River estuary (2.4 days) and in delineating the relative contribution to the water masses in Ossabaw and Port Royal Sounds from the River and from sea water. Ossabaw and Port Royal Sounds are located approximately 20 km south and north of the Savannah River estuary, respectively

  2. Waterfowl migration and distribution in North West estuaries. V. 2

    International Nuclear Information System (INIS)

    Clark, N.A.; Kirby, J.S.; Langston, R.H.W.; Donald, P.; Mawdesley, T.; Evans, J.

    1990-12-01

    Waterfowl populations may be affected by the proposed tidal barrage across the Mersey. A study was performed with three objectives: (1) to evaluate the patterns of usage of the intertidal flats of the Mersey estuary by waders and wildfowl and to establish which are the preferred areas; (2) to identify the places of origin and movement patterns of the populations of waders and wildfowl that visit the Mersey estuary; and (3) to evaluate evidence regarding the capacity of British estuaries to absorb waders and wildfowl populations which might be displaced by a Mersey Barrage. The text and tables of results of this study have already been presented in Volume 1. Volume 2 contains the figures describing the results (U.K)

  3. Tritium in the Savannah River estuary and adjacent marine waters

    International Nuclear Information System (INIS)

    Hayes, D.W.

    1979-01-01

    The tritium distribution in the Savannah River estuary and adjacent marine waters was measured to provide information on the dilution, mixing and movement of Savannah River water in this region. The Savannah River marine region was chosen because the average tritium concentration in this river is approximately 5 pCi/ml, whereas other rivers in the southeastern United States of America average less than 0.5 pCi/ml. The increased tritium concentration in the Savannah River is due to releases from the Savannah River Plant of the Department of Energy. Tritium measurements have proved particularly effective in estimating the flushing time of the Savannah River estuary (2.4 days) and in delineating the relative contribution to the water masses in Ossabaw and Port Royal Sounds from the river and from sea-water. Ossabaw and Port Royal Sounds are located approximately 20 km south and north of the Savannah River estuary respectively. (author)

  4. Variaciones en la estacionalidad de polen y esporas fúngicas en la atmósfera de la ciudad de La Plata (Argentina Seasonal variation of pollen and fungal spores in the atmosphere of Plata city (Argentina

    Directory of Open Access Journals (Sweden)

    Daniela S Nitiu

    2011-12-01

    Full Text Available Se presentan los primeros datos sobre variaciones estacionales de polen y esporas fúngicas en su conjunto en la atmósfera de la ciudad de La Plata durante julio 2000 / junio 2001. El total de bioaerosoles fue de 201889.15 de los cuales el 15% correspondió a 54 tipos polínicos y el 85% a 79 tipos esporales. El Índice Polínico estuvo dado en un 74% por Polen Arbóreo (PA y en un 26% por Polen Herbáceo (PNA. La máxima concentración de PA tuvo lugar en septiembre con granos provenientes de Platanus y Fraxinus. El PNA presentó dos picos, el primero en diciembre procedente de Poaceae y el segundo en marzo debido a Ambrosia. Con respecto al componente fúngico, se identificaron esporas de Oomycota, Zygomycota, Myxomycota, Ascomycota y Basidiomycota. Estos bioaerosoles estuvieron presentes durante todo el año y en altas concentraciones siendo más abundantes en verano - otoño Las mitosporas de Hongos Imperfectos dominan la nube superando el 44% del total del Índice Esporal. El máximo aporte se registró en febrero dado por las esporas de Cladosporium. Se identificaron dos períodos estacionales en los cuales se hallan simultáneamente altas concentraciones de polen y esporas fúngicas. El primero se desarrolla en primavera y está integrado por Platanus, Fraxinus y Aspergillus / Penicillium y el segundo es estival e involucra a Ambrosia, Alternaria y Cladosporium.We present the first data on representativeness and seasonal variation of pollen and fungal spores as a whole in the atmosphere of the city of La Plata during july 2000 / june 2001. Total was 201889.15 bioaerosols, 15% of which was contributed by 54 pollen types and 85% by 79 spore types. The Pollinic Index came from arboreal pollen (PA in 74% and herbaceous pollen (PNA in 26%. The PA maximum concentration took place in september due to Platanus and Fraxinus. The PNA presented two peaks, one in december due to Poaceae, and the other one in march from Ambrosia. In regard to the

  5. Renovating the Main Building

    CERN Multimedia

    CERN Bulletin

    2010-01-01

    CERN's "Main Building" is exactly that. The Organization's central hub, with hundreds of staff and visitors passing through its doors every day, will soon be getting a well-earned facelift. Refurbishment work will proceed in phases, starting with the Salle des Pas Perdus, the concourse between the Council Chamber and the Main Auditorium. By the end of August, informal seating areas will be installed, electronic display panels will provide practical information and improved sound insulation will enhance conditions in the auditoria and surrounding meeting rooms.   In light green the area that will undergo the facelift. Work will start in July. The ground floor is home to the entrance to Restaurant No. 1, the bank, the post office, the travel agent, the Users Office, the Staff Association, the notice boards etc. Step up to the first floor to access CERN's largest lecture theatre, the Council Chamber and its "Pas Perdus" lobby. Everyone who works at or visits CERN i...

  6. Radium isotopes in the Orinoco estuary and Eastern Caribbean Sea

    International Nuclear Information System (INIS)

    Moore, W.S.; Todd, J.F.

    1993-01-01

    Radium isotopes provide a means of identifying the source of freshened waters in the ocean and determining the time elapsed since these waters were in the estuary. The authors present evidence that during April, waters from the Amazon mixing zone pass within 50 km of the mouth of the Orinoco River. These Amazon waters are characterized by a lower 228 Ra/ 226 Ra activity ratio (AR) than are waters from the Orinoco at similar salinities. During autumn, the increased discharge of the Orinoco displaces the freshened Amazon waters seaward, yet the two can be distinguished clearly. Within the Caribbean Sea, waters of Orinoco origin carry a characteristic radium signature including excess activities of 224 Ra. This isotope may be used to estimate the time elapsed since the waters were removed from contact with sediments. Current speeds based on 224 Ra dating ranged from 15 to 33 cm/s during April. The radium isotopes also provide an assessment of sediment mixing in the estuary. During low discharge (April), considerable mixing of older sediment by physical or biological processes or dredging maintained high activities of 228 Ra in the estuary and produced the highest 228 Ra/ 226 Ra AR's yet measured in any estuary. During high discharge (September), a large fraction of the 228 Ra was derived from desorption from fresh sediment rather than mixing of older sediments. Activities of 224 Ra were high in the estuary during both high and low discharge, indicating that considerable mixing of recently introduced sediment must occur during each period. During April, 224 Ra and 228 Ra activities in the water were about equal, indicating that most of the sediment being resuspended had been stored in the estuary long enough to reestablish radioactive equilibrium in the 232 Th decay series (i.e., 20 years). 19 refs., 11 figs., 3 tabs

  7. Modelling extreme climatic events in Guadalquivir Estuary ( Spain)

    Science.gov (United States)

    Delgado, Juan; Moreno-Navas, Juan; Pulido, Antoine; García-Lafuente, Juan; Calero Quesada, Maria C.; García, Rodrigo

    2017-04-01

    Extreme climatic events, such as heat waves and severe storms are predicted to increase in frequency and magnitude as a consequence of global warming but their socio-ecological effects are poorly understood, particularly in estuarine ecosystems. The Guadalquivir Estuary has been anthropologically modified several times, the original salt marshes have been transformed to grow rice and cotton and approximately one-fourth of the total surface of the estuary is now part of two protected areas, one of them is a UNESCO, MAB Biosphere Reserve. The climatic events are most likely to affect Europe in forthcoming decades and a further understanding how these climatic disturbances drive abrupt changes in the Guadalquivir estuary is needed. A barotropic model has been developed to study how severe storm events affects the estuary by conducting paired control and climate-events simulations. The changes in the local wind and atmospheric pressure conditions in the estuary have been studied in detail and several scenarios are obtained by running the model under control and real storm conditions. The model output has been validated with in situ water elevation and good agreement between modelled and real measurements have been obtained. Our preliminary results show that the model demonstrated the capability describe of the tide-surge levels in the estuary, opening the possibility to study the interaction between climatic events and the port operations and food production activities. The barotropic hydrodynamic model provide spatially explicit information on the key variables governing the tide dynamics of estuarine areas under severe climatic scenarios . The numerical model will be a powerful tool in future climate change mitigation and adaptation programs in a complex socio-ecological system.

  8. Fermilab Main Injector plan

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    1990-07-15

    The Fermilab Main Injector is the centrepiece of the 'Fermilab III' scheme to significantly upgrade the Laboratory's existing accelerator complex. The new accelerator is designed to provide increased particle beam levels to boost the collision rate in the Tevatron proton-antiproton collider (luminosity in excess of 5 x 10{sup 31} per sq cm per s) and, if approved, would provide increased flexibility in all areas of high energy physics research.

  9. Fermilab Main Injector plan

    International Nuclear Information System (INIS)

    Anon.

    1990-01-01

    The Fermilab Main Injector is the centrepiece of the 'Fermilab III' scheme to significantly upgrade the Laboratory's existing accelerator complex. The new accelerator is designed to provide increased particle beam levels to boost the collision rate in the Tevatron proton-antiproton collider (luminosity in excess of 5 x 10 31 per sq cm per s) and, if approved, would provide increased flexibility in all areas of high energy physics research

  10. Maine coast winds

    Energy Technology Data Exchange (ETDEWEB)

    Avery, Richard

    2000-01-28

    The Maine Coast Winds Project was proposed for four possible turbine locations. Significant progress has been made at the prime location, with a lease-power purchase contract for ten years for the installation of turbine equipment having been obtained. Most of the site planning and permitting have been completed. It is expect that the turbine will be installed in early May. The other three locations are less suitable for the project, and new locations are being considered.

  11. Project evaluation: main characteristics

    OpenAIRE

    Moutinho, Nuno

    2010-01-01

    — The evaluation process of real investment projects must consider not only the traditional financial approach, but also non-financial aspects. Non financial analysis can provide additional relevant information about projects. We investigate financial and non-financial areas most relevant in project appraisal. We present main critical success factors and areas of analysis that lead to the perception of project success. Finally, companies are segmented to verify its financial and non-financial...

  12. Marketing Maine Tablestock Potatoes

    OpenAIRE

    Berney, Gerald; Grajewski, Gregory; Hinman, Don; Prater, Marvin E.; Taylor, April

    2010-01-01

    The Marketing Services Division of USDA’s Agricultural Marketing Service (AMS) was asked by USDA’s Agricultural Research Service (ARS) National Program Leader and ARS’s New England Soil and Water Research Laboratory personnel to help with existing efforts to assist Maine fresh potato farmers in their search for alternative marketing strategies, and reverse the recent decline in the profitability of their operations. ARS researchers previously had conducted an exhaustive study defining possibl...

  13. 76 FR 9709 - Water Quality Challenges in the San Francisco Bay/Sacramento-San Joaquin Delta Estuary

    Science.gov (United States)

    2011-02-22

    ... Water Quality Challenges in the San Francisco Bay/Sacramento-San Joaquin Delta Estuary AGENCY... the San Francisco Bay/ Sacramento-San Joaquin Delta Estuary (Bay Delta Estuary) in California. EPA is... programs to address recent significant declines in multiple aquatic species in the Bay Delta Estuary. EPA...

  14. Intersecciones entre Violencia de Género, Pobreza y Acceso a la Justicia: El Caso de la Ciudad de La Plata (Links between Gender-based Violence, Poverty and Access to Justice: The Case of the City of La Plata

    Directory of Open Access Journals (Sweden)

    Manuela Graciela González

    2015-06-01

    Full Text Available A critical reflection on the experience at Courts of female victims of gender violence is the aim of this paper. Provincial, national and international laws are the framework for the analysis. The raw material are their reports ( assesed from the perspective of the newest writings on the issue which stress the differences between the official discourse of the Administration of Justice and the victims' "accounts". Three different questions have been asked to guide our research: Are gender violence and poverty , factors linked to the lack of an effective Access to Justice? Which are the new factors observed everywhere and those which are present only in Latin America?Are there any changes in the social stereotypes which clear and ease the womens' path towards the administration of justice? En este artículo reflexionamos críticamente sobre la situación de las mujeres en La Plata-Argentina que padecen violencia de género cuando acceden a la administración de justicia. Para ello tomamos como marco referencial la normativa provincial, nacional e internacional. Utilizamos como insumo los testimonios de las mujeres, analizados a la luz de la literatura actual, que polemiza sobre la compleja y a veces contradictoria relación entre el discurso "oficial" de la Administración de justicia y los "relatos" de las mujeres. Nos interrogamos sobre tres ejes de trabajo que han orientado nuestra producción: ¿Qué intersecciones visualizamos entre violencia de género y pobreza como factores que obstaculizan el acceso a la justicia?¿Qué factores nuevos aparecen en contextos globalizados, y cuales son específicos de América Latina?¿Se observan cambios en los estereotipos sociales que despejan el camino de las mujeres a la administración de justicia? DOWNLOAD THIS PAPER FROM SSRN: http://ssrn.com/abstract=2611592

  15. Optical Changes in a Eutrophic Estuary During Reduced Nutrient Loadings

    DEFF Research Database (Denmark)

    Pedersen, Troels Møller; Sand-Jensen, Kaj; Markager, Stiig

    2014-01-01

    Loss of water clarity is one of the consequences of coastal eutrophication. Efforts have therefore been made to reduce external nutrient loadings of coastal waters. This paper documents improvements to water clarity between 1985 and 2008–2009 at four stations in the microtidal estuary Roskilde...... to 74 % in 1985 to 78 to 85 % in 2008–2009. Overall, efforts to reduce nutrient loading and improve water clarity appeared to have had a larger impact on POM* than on Chl a and colored dissolved organic matter concentrations in the estuary, which can account for the decrease in the scatter...

  16. Impacts of pesticides in a Central California estuary.

    Science.gov (United States)

    Anderson, Brian; Phillips, Bryn; Hunt, John; Siegler, Katie; Voorhees, Jennifer; Smalling, Kelly; Kuivila, Kathy; Hamilton, Mary; Ranasinghe, J Ananda; Tjeerdema, Ron

    2014-03-01

    Recent and past studies have documented the prevalence of pyrethroid and organophosphate pesticides in urban and agricultural watersheds in California. While toxic concentrations of these pesticides have been found in freshwater systems, there has been little research into their impacts in marine receiving waters. Our study investigated pesticide impacts in the Santa Maria River estuary, which provides critical habitat to numerous aquatic, terrestrial, and avian species on the central California coast. Runoff from irrigated agriculture constitutes a significant portion of Santa Maria River flow during most of the year, and a number of studies have documented pesticide occurrence and biological impacts in this watershed. Our study extended into the Santa Maria watershed coastal zone and measured pesticide concentrations throughout the estuary, including the water column and sediments. Biological effects were measured at the organism and community levels. Results of this study suggest the Santa Maria River estuary is impacted by current-use pesticides. The majority of water samples were highly toxic to invertebrates (Ceriodaphnia dubia and Hyalella azteca), and chemistry evidence suggests toxicity was associated with the organophosphate pesticide chlorpyrifos, pyrethroid pesticides, or mixtures of both classes of pesticides. A high percentage of sediment samples were also toxic in this estuary, and sediment toxicity occurred when mixtures of chlorpyrifos and pyrethroid pesticides exceeded established toxicity thresholds. Based on a Relative Benthic Index, Santa Maria estuary stations where benthic macroinvertebrate communities were assessed were degraded. Impacts in the Santa Maria River estuary were likely due to the proximity of this system to Orcutt Creek, the tributary which accounts for most of the flow to the lower Santa Maria River. Water and sediment samples from Orcutt Creek were highly toxic to invertebrates due to mixtures of the same pesticides measured

  17. Physical biological coupling in the Pearl River Estuary

    Science.gov (United States)

    Harrison, Paul J.; Yin, Kedong; Lee, J. H. W.; Gan, Jianping; Liu, Hongbin

    2008-07-01

    The Pearl River Estuary is a subtropical estuary and the second largest in China based on discharge volume from the Pearl River. Processes in the estuary vary spatially and temporally (wet vs dry season). In the dry season at the head of the estuary, hypoxic and nearly anoxic conditions occur and NH 4 reaches >600 μM, NO 3 is ˜300 μM and nitrite is ˜60 μM indicating that nitrification and denitrification may be important dry season processes in the region extending 40 km upstream of the Humen outlet. There are very few biological studies conducted in this upper section of the estuary in either the dry or wet seasons and hence there is a need for further research in this region of the river. In the wet season, the salinity wedge extends to the Hongqimen outlet and oxygen is low (35-80% saturation). Nitrate is ˜100 μM, silicate ˜140 μM; and phosphate is relatively low at ˜0.5 μM, yielding an N:P ratio up to ˜200:1 in summer. Nutrients decrease in the lower estuary and primary productivity may become potentially P-limited. Eutrophication is not as severe as one would expect from the nutrient inputs from the Pearl River and from Hong Kong's sewage discharge. This estuary shows a remarkable capacity to cope with excessive nutrients. Physical processes such as river discharge, tidal flushing, turbulent dispersion, wind-induced mixing, and estuarine circulation play an important role in controlling the production and accumulation of algal blooms and the potential occurrence of hypoxia. Superimposed on the physical processes of the estuary are the chemical and biological processes involved in the production of the bloom. For example, the 100N:1P ratio indicates that P potentially limits the amount of algal biomass (and potential biological oxygen demand) in summer. While extended periods of hypoxia are rare in Hong Kong waters, episodic events have been reported to occur during late summer due to factors such as low wind, high rainfall and river discharge which

  18. Development of an integrative approach for the characterization of environmental risk on marine transition ecosystems: the Sado estuary as a case study

    Directory of Open Access Journals (Sweden)

    Filipa Maria Pereira

    2014-05-01

    Full Text Available Estuaries and transitional waters are important ecosystems from which organisms and humans are dependent on for survival. They are important as nursery areas and shelter for many aquatic organisms, from which humans and their economical activities are dependent on. Humans also depend on estuaries for other reasons such as tourism, heavy industry, aquaculture and shipping. The degradation of estuarine environmental quality implies ecologic, economic and social prejudice, so it is important to evaluate the state of the environment to assist management. The Sado estuary (SW Portugal is considered moderately contaminated. The area is impacted by diverse human activities, from shipping, industry, urbanism and even mariculture and agriculture activities. Because Sado estuary is very important for human and ecological reasons, many studies were conducted by several researchers in past few years, albeit scattered. As such, there was a need to integrate the information hitherto produced, in order to obtain a clear and complete image of the overall environmental quality status of the area, to assist future management plans and decision-making. For the purpose, a geographical information system (GIS was created from sediment contamination and biomarker data collected from a decade-long time-series of publications. Five distinct areas were identified from the Sado estuary: a clean area plus four contaminated areas characterized by distinct sediment contamination patterns, related to different pollution hot spots and diffuse contamination sources. Also, in spite of the multiple biological traits under survey, the biomarker data (from several organisms are in general agreement with the environmental contamination georeferencing information. Through this evaluation, the main anthropogenic sources of pollutants were identified, namely, the shipyard area and adjacent industrial belt, followed by urban and agricultural inputs into the estuary. From the data it is

  19. Distribution of radioactivity in the Esk Estuary and its relationship to sedimentary processes

    International Nuclear Information System (INIS)

    Kelly, M.; Emptage, M.

    1992-01-01

    In the Esk Estuary, Cumbria, the distribution of sediment lithology and facies has been determined and related to radionuclide surface and sub-surface distribution. The total volume of sediment contaminated with artificial radionuclides is estimated at 1.2 Mm 3 and the inventory of 137 Cs at 4.5 TBq. The fine grained sediments of the bank facies are the main reservoir for radionuclides, comprising 73% of the 137 Cs inventory. Time scales for the reworking of these sediments are estimated at tens to hundreds of years. Measurements of sediment and radionuclide deposition demonstrate that direct sediment deposition is the main method for radionuclide recruitment to the deposits but solution labelling can also occur. Bioturbation and other diagenetic processes modify the distribution of radionuclides in the deposits. Gamma dose rates in air can be related to the sediment grain size and sedimentation rate. (Author)

  20. Quagga mussels Dreissena rostriformis burgensis (Andrusov, 1897) in the Main River (Germany)

    OpenAIRE

    Velde, G. van der; Platvoet, D.

    2007-01-01

    The first record of the quagga mussel Dreissena rostriformis bugensis (Andrusov, 1897) in Germany is described. This species has expanded its distribution area in Europe at a slower rate than the zebra mussel Dreissena polymorpha (Pallas, 1771). Recent records from the Danube in Romania and from an enclosed Rhine-Meuse estuary in The Netherlands, suggest that the Main-Danube canal and River Rhine have functioned as the dispersal pathway of the quagga mussel to The Netherlands. The record of t...