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Wyszukujesz frazę "estuarine sediment" wg kryterium: Temat


Wyświetlanie 1-5 z 5
Tytuł:
Mikrokonkrecje syderytowe w holoceńskich osadach ujścia rzeki Gwadiana w Portugalii : raport wstępny
Micro-scale sideritic concretions in Holocene sediments in the Guadiana estuary, Portugal : a preliminary report
Autorzy:
Wilamowski, A.
Boski, T.
Moura, D.
Powiązania:
https://bibliotekanauki.pl/articles/2075017.pdf
Data publikacji:
2013
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
siderite
concretions
estuarine sediment
Guadiana River
Holocene
syderyt
konkrecje
sedymentacja osadów
rzeka Gwadiana
holocen
Opis:
The authors described micro-scale carbonate concretions occurring at a depth of about 41 m within Holocene sandy sediments filling the Guadiana River paleovalley, representing the transitional fluvial- -estuarine facies. Despite their minute sizes, the micro-concretions show a complex internal structure. Regular distribution of Mg, Mn and Ca can be assigned to a chemical zoning, pointing to precipitation under varying chemical conditions. Based on morphological and chemical peculiarities, four types of concretions can be distinguished. Detrital Fe-Mg-carbonates form nuclei. At first, Mn-rich carbonate precipitated as a coating, which is coherent with the sequence of precipitation of carbonates associated with bacteria-mediated oxidation of organic matter. Subsequently, the main bodies of concretions precipitated as Fe-carbonate (siderite). The last precipitation episode is marked by enrichment in Ca. The XRD patterns show the presence of a mixture of discrete carbonate phases.
Źródło:
Przegląd Geologiczny; 2013, 61, 10; 568--575
0033-2151
Pojawia się w:
Przegląd Geologiczny
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Natural versus anthropic causes in variations of sand export from river basins: an example from the Guadiana River Mouth (Southwestern Iberia)
Autorzy:
Dias, J. M. A.
Gonzales, R.
Ferreira, Ó.
Powiązania:
https://bibliotekanauki.pl/articles/1187374.pdf
Data publikacji:
2004
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
Guadiana River
sediment transport
estuarine sand bodies
floods
NAO
anthropic influence
Opis:
Flood events in many river basins with highly variable discharge values remove accumulated sediments from the riverbed and estuaries. These sediments are exported to the shelf and the adjacent coastlines. Data for rainfall and river discharge for the Guadiana River basin in southwestern Iberia show a strong link with North Atlantic Oscillation (NAO) index patterns. A negative NAO index usually results in more rainfall, and subsequent flooding in the river basin during winter months. During the second half of the 20th century, the flow regime of the Guadiana River and its tributaries have been increasingly constrained by the construction of dams. The consequences were a reduction of coarse-grained sediment export from the upper river basin to the estuary, and a reduction in the number and type of floods.
Źródło:
Polish Geological Institute Special Papers; 2004, 11; 95-102
1507-9791
Pojawia się w:
Polish Geological Institute Special Papers
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Butyltins and phenyltins in biota and sediments from the Lagoon of Venice
Autorzy:
Bortoli, A.
Troncon, A.
Dariol, S.
Pellizzato, F.
Pavoni, B.
Powiązania:
https://bibliotekanauki.pl/articles/47897.pdf
Data publikacji:
2003
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
biota
estuarine ecosystem
phenyltin
Venice Lagoon
butyltin
sediment
organotin compound
contamination impact
Opis:
Sediments and organisms were sampled to determine organotin contents – butyltins (BTs) and phenyltins (PhTs) – at 12 locations in an estuarine ecosystem, the Lagoon of Venice, characterised by varying contamination impacts. The results showed that organotin contamination in sediments is at lower levels, ranging from 2.5±0.1 to 84±1 ng g−1 (d.w.) for ΣBTs and from 0.8±0.2 to 7±1 ng g−1 (d.w.), for ΣPHTs, than in organisms, where the highest concentrations were found in filter feeders like mussels – from 60±3 to 7632±148 ng g−1 (d.w.) for ΣBTs and from 0.80±0.01 to 4005±121 ng g−1 (d.w.) for ΣPHTs. The possible risk to human health was assessed on the basis of the consumption of edible species sampled in some areas of the lagoon.
Źródło:
Oceanologia; 2003, 45, 1
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Wave-induced bottom shear stress estimation in shallow water exemplified by using deep water wind statistics
Autorzy:
Myrhaug, D.
Powiązania:
https://bibliotekanauki.pl/articles/47582.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
shallow water
deep water
wind
water
circulation model
shear stress
mud deposit
coastal zone
estuarine zone
bottom sediment
Opis:
The paper provides a simple and analytical method which can be used to give estimates of the wave-induced bottom shear stress for very rough beds and mud beds in shallow water based on wind statistics in deep water. This is exemplified by using long-term wind statistics from the northern North Sea, and by providing examples representing realistic field conditions. Based on, for example, global wind statistics, the present results can be used to make estimates of the bottom shear stress in shallow water.
Źródło:
Oceanologia; 2017, 59, 2
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Environmental cadmium and lead concentrations in the Bahia Blanca Estuary (Argentina). Potential toxic effects of Cd and Pb on crab larvae
Autorzy:
Ferrer, L.
Contardi, E.
Andrade, S.J.
Asteasuain, R.
Pucci, A.E.
Marcovecchio, J.E.
Powiązania:
https://bibliotekanauki.pl/articles/48726.pdf
Data publikacji:
2000
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
organic matter
estuarine water
Bahia Blanca Estuary
environment
lead concentration
pH
toxic effect
sediment
crab
cadmium concentration
Argentina
temperature
salinity
larva
Chasmagnathus granulata
Opis:
The Bahia Blanca Estuary includes a large tidal plain with an area close to 1150 km2.Mud is predominant in its sediments, where a significant population of the crab Chasmagnathus granulata lives during the whole year.Mo reover, there are important urban and industrial discharges into this environment. Cd and Pb concentrations were determined in samples of water (for both dissolved and suspended particulate matter) and surface sediments (total and <63 μm fractions).Or ganic matter was analysed in the sediments, while temperature, salinity, pH and dissolved oxygen were measured in the estuarine water The metal concentrations determined in this study were: 1.47 ± 1.08 μg Cd g−1 and 14.68 ± 4.31 μg Pb g−1 in surface sediments; 2.21 ± 1.33 μg Cd g−1 and 25.70 ± 7.09 μg Pb g−1 in the <63 μm sediment fraction; 0.18 ± 0.11 μg Cd g−1 and below the analytical detection limit of Pb in suspended particulate matter. Furthermore, dissolved Cd and Pb were lower than the norms for marine and estuarine waters (2 μg dm−3 for Cd and 5 μg dm−3 for Pb, E.P.A.). Simultaneously, the effects of Cd and Pb were studied on recently hatched larvae of Ch. granulata, through 96-hour semi-static acute assays.Via bility was the criterion assessed in the assays.LC 50 (96 h) for Cd was 46.43 μg dm−3 (36.92 − 56.34 μg dm−3), whilst that for Pb was 1. 0 mg dm−3 (0.79 − 1.23 mg dm−3), which demonstrates that Cd is more toxic towards larvae.F inally, both LC50 values determined for Cd and Pb were higher than the corresponding metal concentrations measured in the Bah´ıa Blanca environment.
Źródło:
Oceanologia; 2000, 42, 4
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-5 z 5

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