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  • 1
    Digitale Medien
    Digitale Medien
    [s.l.] : Nature Publishing Group
    Nature 299 (1982), S. 52-54 
    ISSN: 1476-4687
    Quelle: Nature Archives 1869 - 2009
    Thema: Biologie , Chemie und Pharmazie , Medizin , Allgemeine Naturwissenschaft , Physik
    Notizen: [Auszug] During 1976-77 and 1980-81 austral summers, sediments, epibenthic algae and moss were collected from the dry valleys of Victoria Land in the Antarctic (Fig. 1, Table 1). Characteristics of the dry valley lakes are described elsewhere13'17. The lakes and ponds studied are all saline. The primary ...
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 2
    Digitale Medien
    Digitale Medien
    [s.l.] : Nature Publishing Group
    Nature 290 (1981), S. 688-690 
    ISSN: 1476-4687
    Quelle: Nature Archives 1869 - 2009
    Thema: Biologie , Chemie und Pharmazie , Medizin , Allgemeine Naturwissenschaft , Physik
    Notizen: [Auszug] During the 1967-77 austral summer, soil samples were collected from the dry valleys of Victoria Land in Antarctica (Fig. 1) with a small stainless-steel scoop, wrapped in Teflon sheet and stored at temperatures below 0 C until analysis. The procedures for fatty acid analysis have been described in ...
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 3
    ISSN: 1573-5117
    Schlagwort(e): Antarctic pond ; Labyrinth ; chemical element ; stable isotopic ratio ; water source ; salt origin
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract A large number of fresh water and saline ponds are located in the Labyrinth (77° 33′ S, 160° 50′ E) of the upper Wright Valley in the Dry Valleys region of southern Victoria Land, Antarctica. It is situated near the terminus of the Wright Upper Glacier between 800–1000 m above sea level. From a limnological point of view, the most interesting problems concerning these saline ponds are the origin of their salts and their evolutional history. Chloride ion contents vary remarkably among the ponds ranging from 0.0049 to 52.4 g kg−1. Surprisingly, more than a half of the ponds are saline with the highest chloride ion content being 2.7 times greater than that of seawater. The δD and δ18O values of the pond waters indicate a snow and/or glacial meltwaters origin, and that the ponds underwent subsequent alteration due to evaporation or freezing. The composition of chemical components reveal no evidence of trapped seawater. Thus the salt concentrations in the Labyrinth pond waters must be explained principally by the accumulation of atmospheric salts and subsequent repeated cycles of evaporation and freezing of the pond waters over considerable time periods.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 4
    Digitale Medien
    Digitale Medien
    Springer
    Hydrobiologia 111 (1984), S. 119-126 
    ISSN: 1573-5117
    Schlagwort(e): vertical distribution ; organic constituents ; organic carbons ; fatty acids ; sterols ; Antarctic lake
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Vertical distribution of organic constituents, i.e. total organic carbon (TOC), extractable organic carbon with ethyl acetate (EOC), hydrocarbons, phytol, sterols, fatty acids and phenolic acids in Lake Vanda was studied to elucidate their features in relation to the stratification of lake water and the distribution of lake organisms. The concentrations of TOC, EOC and sterols increased with depth and attained the maximum values of 25 and 1.5 mgC l−1 and 1.4 μg l−1 in the bottom, respectively, while those of fatty acids showed the maximum value of 61 μg l−1 at a depth of 55.4 m, along with the highest value of the ratio of unsaturated (UC16, uC18) to saturated (C16, C18) acids (8.5) and with the highest carbon preference index (35). Hydrocarbons were only found in the bottom layers (60.4 and 65.9 m) and bottom sediment. These results suggest strongly that the vertical distribution of lake organisms and their activity are quite different due to depth. In the bottom warm anoxic layers the degradation of organic materials must have occurred significantly and thus refractory organic materials should be concentrated.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 5
    ISSN: 1573-5117
    Schlagwort(e): vertical distribution ; total bacterial number ; bacterial biomass ; Caulobacter ; phototrophic bacteria ; Antarctic lake
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Vertical distribution of bacteria in Lake Vanda, an Antarctic meromictic lake, was examined by the acridine orange epifluorescence direct count method. Total bacteria were 104–105 cells · ml−1 in the water at 55 m depth and above, and increased drastically to 107 cells · ml−1 in the bottom water. Filamentous or long rodshaped bacteria occurred at a high frequency in the upper layers, but in the bottom layers most bacteria were coccoidal or short rods. Mean bacterial cell volume in water of between 10 m and 60 m deep was fairly large compared with common bacterial populations in seawater and lake water. Aerobic heterotrophic bacteria were recovered from the water of a depth of 30 m and above, and were assumed to belong to Caulobacter. Viable heterotrophic bacteria were not recovered from the high salinity deep water by media prepared with the same deep water. Phototrophic purple non-sulphur bacteria were isolated by enrichment cultures from water at 55 m depth.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 6
    Digitale Medien
    Digitale Medien
    Springer
    Hydrobiologia 172 (1989), S. 265-299 
    ISSN: 1573-5117
    Schlagwort(e): Antarctic lake ; biogeochemistry ; organic substance ; stratification ; hydrocarbon ; fatty acid ; sterol ; phenolic acid ; hydroxy acid ; ketone
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The features of organic constituents in Antarctic lakes and ponds of the McMurdo, Syowa and Vestfold oases are summarised from a biogeochemical viewpoint. Total organic carbon or dissolved organic carbon contents in saline lakewaters are generally extremely high and much higher than those in freshwater lakes. The concentrations and/or compositions of hydrocarbons, fatty acids, sterols, phenolic acids and hydroxy acids in lake and pond waters and sediments vary markedly, probably reflecting differences in biological activity and source organisms. Long-chain alkenes, such as n-C29:2 (carbon chain length: numbers of unsaturated bonds) are found as the major hydrocarbons in some anoxic lake sediments. Unusually, long-chain n-alkanoic acids are abundant in some Antarctic lake sediments and 24-ethylcholest-5-en-3β-ol is the most prominent sterol in most of the lakes studied. It is suggested that some bacteria, and cyanobacteria and algae are important sources of long-chain n-alkanoic acids and 24-ethylcholest-5-en-3β-ol, respectively, as previously reported from environments of the mid and lower latitudes. The dominance of p-hydroxybenzoic acid among the phenolic acids found together with the absence of syringic, p-coumaric and ferulic acids in the Antarctic lakes reflects the absence of vascular plants in the areas studied. In three Antarctic saline lakes (Vanda, Fryxell and Ace) the kinds and amounts of organic constituents differ with depth due to the zonation of microorganisms. The maximum fatty acid contents are found at depths just above the anoxic layer, corresponding to the photosynthetic maxima in the lakes, and the depths of maximum phytoplankton populations. In the bottom sediments of the lakes, the composition of organic substances is significantly different from that in the water columns, indicating that the sinking organic substances are degraded rapidly by microorganisms on the lake bottom.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 7
    Digitale Medien
    Digitale Medien
    Springer
    Hydrobiologia 172 (1989), S. 291-303 
    ISSN: 1573-5117
    Schlagwort(e): Antarctic lake ; Lake Fryxell ; vertical distribution ; water ; sediment ; organic constituents ; total organic carbon ; hydrocarbon ; fatty acid ; hydroxy acid
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Vertical distribution of organic constituents, i.e. total organic carbon (TOC), hydrocarbons, fatty acids and hydroxy acids in water and sediment samples from Lake Fryxell (77° 35′ S, 163° 15′ E) of southern Victoria Land, Antarctica were studied to elucidate their features in relation to stratification of the lake waters and likely distribution of microorganisms. The TOC content of the surface water (5.0 m; just below the ice cover of 4.50 m thickness) was 1.4 mg l−1. It increased markedly with depth and attained a maximum value of 21.7 mg C l−1 at a depth of 17.5 m, but decreased to the bottom (13.3 mg C l−1). The high TOC content of the anoxic bottom layers (〉 15 m) is attributable to the concentration of refractory organic substances over long periods following the degradation of labile organic constituents. Hydrocarbons were not found in the water column, but the major constituent of the bottom sediment was n-C29 : 2 alkene. Total concentrations of fatty acids in the oxic layers (⩽ 10 m) were highest at 10.0 m and much higher than those in the anoxic layers (〉 10 m), probably reflecting the phytoplankton population. The content of branched (iso and anteiso) fatty acids and 3-hydroxy acids in the anoxic layers were much greater than those in the oxic layers which would seem to reflect the distribution of bacterial abundance. The differences of organic composition between the water column and sediments imply that sinking dead organisms were quickly degraded in the lake bottom. Also, the composition of microorganisms in the water column must be very different from that in the sediments.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 8
    facet.materialart.
    Unbekannt
    PANGAEA
    In:  Supplement to: Torii, Tetsuya; Matsumoto, Genki I; Nakaya, Shyu (1988): 3.3 The chemical characteristics of Antarctic lakes and ponds, with special emphasis on the distribution of nutrients. Polarforschung, 58(2/3), 219-230, hdl:10013/epic.29618.d001
    Publikationsdatum: 2023-05-12
    Beschreibung: This paper reviews Japanese limnological studies mainly in the McMurdo and Syowa oases, with special emphasis on the nutrient distribution. Generally, the chemical composition of the major ionic components in the coastal lakes and ponds is similar to that in seawater, while that in inland Dry Valley lakes and ponds of the McMurdo Oasis is abundant in calcium, magnesium and sulfate ions. The former can be explained by the direct influences of sea salts, while the latter is mainly attributable to the accumulation of atmospheric salts. Most saline lakes are meromictic. Dissolved oxygen concentrations in the upper layers are saturated or supersaturated, but the bottom layers are anoxic and often hydrogen sulfide occurs. The concentrations of nutrients vary largely not only among the lakes but also with depth. Silicate-Si, which is generally abundant in all freshwater and saline lakes, may be due to erosions of soils and rocks. Nitrite-N concentrations in both freshwater and saline lakes are generally low. Nitrate-N concentrations in the oxic layers of the inland saline lakes in the McMurdo Oasis arc often high, but not high in the coastal saline lakes of the Syowa and Vestfold oases. The abundance of phosphate-P and ammonium-N in the bottom stagnant layers of saline lakes can be explained by the accumulation of microbially released nutrients due to the decomposition of organic substances. Nutrients are supplied mainly from meltstreams in the catchment areas, and are proved to play an important role in primary production.
    Schlagwort(e): Ace_Lake; Ace Lake, Long Peninsula, Vestfold Hills, East Antarctica; B-1_Pond; Deep_Lake; Don_Juan_Pond; Dry Valley, Antarctica; Home_Lake; ICEDRILL; Ice drill; L-12_Pond; L-20_Pond; Labyrinth_JoyceL-1_pond; Lake; LAKE; Lake_Bonny_east_lobe; Lake_Bonny_west_lobe; Lake_Brownworth; Lake_Canopus; Lake_Chad; Lake_Fryxell; Lake_Hoare; Lake_Hunazoko; Lake_Joyce; Lake_Midori; Lake_Nurume; Lake_O-ike; Lake_Oyayubi; Lake_Skallen_Oike; Lake_Suribati; Lake_Vanda; Lake_Zakuro; McMurdo Oasis, Antarctica; NF-1_Pond; NF-2_Pond; NF-3_Pond; NF-4_Pond; NF-5_Pond; Onyx_River; Onyx_River-1; Onyx_River-2; Onyx_River-3; Oval_Lake; Sampling lake; Sollas-Lacroix_Glacier; Syowa Oasis, Antarctica; Taylor_Glacier; Vestfold Oasis, Antarctica; Wright_Lower_Glacier
    Materialart: Dataset
    Format: application/zip, 5 datasets
    Standort Signatur Erwartet Verfügbarkeit
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  • 9
    Publikationsdatum: 2023-05-12
    Schlagwort(e): Ace_Lake; Ace Lake, Long Peninsula, Vestfold Hills, East Antarctica; Calcium; Chloride; Deep_Lake; Depth, bathymetric; DEPTH, water; Event label; LAKE; Lake_Hunazoko; Lake_Nurume; Lake_Oyayubi; Lake_Suribati; Lake_Zakuro; Magnesium; Oval_Lake; pH; Potassium; Reference of data; Sampling lake; Sodium; Specific gravity; Sulfate; Syowa Oasis, Antarctica; Temperature, technical; Temperature, water; Vestfold Oasis, Antarctica; Water level; δ18O; δ Deuterium, water
    Materialart: Dataset
    Format: text/tab-separated-values, 117 data points
    Standort Signatur Erwartet Verfügbarkeit
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  • 10
    Publikationsdatum: 2023-05-12
    Schlagwort(e): Calcium; Chloride; DEPTH, water; Event label; L-12_Pond; L-20_Pond; LAKE; Lake_Brownworth; Lake_Canopus; Lake_Midori; Lake_O-ike; Lake_Skallen_Oike; Magnesium; McMurdo Oasis, Antarctica; NF-1_Pond; NF-2_Pond; Potassium; Reference of data; Sampling lake; Sodium; Sulfate; Syowa Oasis, Antarctica
    Materialart: Dataset
    Format: text/tab-separated-values, 63 data points
    Standort Signatur Erwartet Verfügbarkeit
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