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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Marine biology 100 (1989), S. 173-183 
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Rates of oxygen consumption, ammonia excretion and phosphate excretion were measured on a hydromedusae (Aglantha digitale), pteropods (Limacia helicina, Clione limacina), copepods (Calanus finmarchicus, C. glacialis, C. hyperboreus, Metridia longa), an amphipod (Parathemisto libellula), a euphausiid (Thysanoessa inermis) and a chaetognath (Sagitta elegans), all of which were dominant species in the Barents Sea during early summer 1987. Water and ash contents and elemental composition (C and N) were also analysed on the specimens used in these metabolic experiments. Between species variations were 67.8% to 94.7% of wet weight in water content, 6.4% to 56.5% of dry weight in ash content, 16.7% to 61.0% of dry weight in carbon content, and 4.3% to 11.2% of dry weight in nitrogen content. Oxygen consumption rates ranged from 0.33 to 13.8 μl O2 individual-1 h-1, ammonia excretion rates, from 0.0072 to 0.885 μgN individual-1 h-1 and phosphate excretion rates, from 0.0036 to 0.33 μg P individual-1 h-1. In general, higher rates were associated with larger species, but considerable differences were also seen between species. The ratios between the rates (O : N, N : P, O : P) exhibited a wide species-specific variation, indicating differences in dominant metabolic substrates. Typical protein oriented metabolism was identified only in S. elegans. From the results of metabolic rate measurements and elemental analyses, daily losses of body carbon and nitrogen were estimated to be 0.50 to 4.15% and 0.084 to 1.87%, respectively, showing faster turnover rates of carbon than that of nitrogen. Comparison of daily loss of body carbon of the Barents Sea zooplankton with that of the Antarctic zooplankton indicated reduced rates of the former (63% on average).
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Adenine nucleotide levels and the adenylate energy charge (EC) ratio of Mytilus edulis L. were determined at monthly intervals over a one-year cycle. The ATP concentration ranged from 2.7 to 4.7 mg · g-1 dry weight, being significantly (P〈0.05) higher in spering and summer than in autumn and winter. The EC ratio ranged from 0.76 to 0.90 (annual mean 0.84), with the lowest values being found in the autumn. The change in the ATP concentration was related to the annual nutritional and reproductive cycle, as revealed by significant correlations with parameters such as gonad indexes, the contents of carbohydrate and ash, the calorific content, and the individual dry weight. The significant (P〈0.001) seasonal variations in EC reflected mainly variations in the AMP content and showed no clear-cut relation to the overall annual reproductive cycle. It appears that the seasonal variations in the ATP concentration and the EC ratio to a large degree reflected changing weight-proportions of different tissues containing different amounts of adenine nucleotides.
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  • 3
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract From February 24 to April 24, weekly samples were collected at fixed depths at one station in Lindåspollene, a land-locked Norwegian fjord. Adenosine triphosphate (ATP), chlorophyll a, phaeophytin, 14C assimilation, and respiratory activity [electron transport system (ETS) activity] were measured in the net- (〉30 μm) and nanoplankton. Netplankton contained on the average 48% of the total chlorophyll a and 56% of the ATP, but contributed only 7% to the total carbon assimilation and 11% to the ETS activity. The assimilation numbers for net- and nanoplankton ranged from 0 to 1.2 and from 1.5 to 13.2, respectively. At the oxygen/hydrogen sulphide interface, high concentrations of ATP, but not of chlorophyll a, were found in the nanoplankton fraction. Netplankton algae grew actively only in the first phase of the bloom, and nanoplankton predominated later, apparently due to low nutrient concentrations. During the bloom, Skeletonema costatum made up the main part of the biomass. The number of cells in the chains decreased throughout the bloom, possibly reflecting the lowered silicate content. It appeared that only nanoplankton were grazed by zooplankton, while netplankton sank to the bottom and represented input to the benthos.
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Marine biology 62 (1981), S. 119-123 
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The adenylate energy charge ratio (EC) of 8 species of zooplankton ranged from 0.70 to 0.89. Eucalanus subcrassus had significantly (P〈0.05) lower EC when captured during a 30-min tow than during a 3-min tow, indicating stress at capture. The concentration of ATP in the 8 species ranged from 9.1 to 36.0 μg/mg protein and from 0.17 to 15.7 μg/mg dry weight. Excluding a low value for the ctenophore Pleurobrachia sp., the average concentration was 8.1 μg ATP/mg dry weight, which is equivalent to an approximate C/ATP ratio of 50.
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  • 5
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Adenine nucleotides of zooplankton were extracted from freeze-dried individuals killed in liquid nitrogen. 96% of the ATP in frozen samples stored at-26°C degraded to AMP in 8 days, while ATP was stable for the same period in freeze-dried samples. A strong metabolic stress caused by capturing the animals was evidenced by a marked lowering of the energy charge [(ATP)+1/2(ADP)/(ATP)+(ADP)+(AMP)], the natural level of energy charge being restored in about 24 h. The concentration of ATP showed no significant correlation with the dry weight of the individuals of a species nor with the mean dry weight of the species. The ATP concentration showed marked seasonal changes with increasing values during periods of reproduction, which is assumed to reflect an inheretn seasonal rhythm in the metabolism. ATP cannot be used as a general estimator of metabolism as it did not reflect differences in metabolic activity between different-sized individuals or species. The mean energy charge for 13 species was 0.7.
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  • 6
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract An investigation was made into the possible causes for the decline of physiological activities in Acetes sibogae australis Colefax and Acartia australis Farran during their maintenance for a period of 2 d following capture. Physiological activities comprising respiration, electron transport system (ETS) activity and excretion of ammonia and phosphate, and the biochemical components protein, RNA, ATP and adenylate energy charge (EC) were measured. Excluding fluctuation in the ammonia excretion rate, physiological rates and biochemical components decreased on an individual basis with time after capture for both species for this period. These decreases were generally moderated if expressed on a protein basis. Notwithstanding these changes, the adenylate EC of both species was constant at the normal level. From the results of stable EC and other physiological and biochemical consequences, it was concluded that food shortage rather than capture stress was the major factor contributing to decreases in the various physiological and biochemical properties of the two zooplankton species studied.
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  • 7
    Publication Date: 2016-07-13
    Description: Sampling of euphausiids is difficult because of their intermediate size between macrozooplankton and micronekton. The Barents Sea is one of the few marine areas where there have been long-term studies of euphausiids. We have examined three monitoring datasets on euphausiids and consider likely sources of errors associated with the sampling. Results indicated a high degree of patchiness in the distribution of euphausiids, even at the largest scale of sampling with a pelagic trawl. This indicates that euphausiids may occur in large, but infrequent, swarms that have a low probability of being sampled by small nets. The mean biomass of euphausiids sampled with MOCNESS was 2 g wet weight m –2 integrated over the water column, which is an underestimate due to avoidance of large individuals. The mean biomass obtained with pelagic trawl in the upper 60 m of water at night during an autumn survey was 10 g wet weight m –2 . The plankton net on bottom trawl collected mean and median density of euphausiids (0.1–0.2 g wet weight m –3 ) near bottom during a winter survey similar to the values found with pelagic trawl in the upper layer during autumn. The mean density for the autumn survey showed an increase from 2000 to 2011, while the winter survey showed generally a decrease from 2000–2007 to 2011. The increase in the autumn series coincided with a general warming trend presumably with a larger influx of euphausiids with Atlantic water, notably of Meganyctiphanes norvegica . In contrast, the decline during winter may reflect a decrease, particularly of Thysanoessa raschii in the southeastern Barents Sea in the most recent years. Improvements in sampling gears combined with more and better use of acoustical and optical technologies offer great promise for improved monitoring and quantification of the roles of euphausiids in the Barents Sea ecosystem.
    Print ISSN: 1054-3139
    Electronic ISSN: 1095-9289
    Topics: Biology , Geosciences , Physics
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  • 8
    Publication Date: 2015-01-20
    Description: Benthos plays a significant role as substrate, refuge from predation and food for a wide variety of fish and invertebrates of all life stages and should therefore be considered in the ecosystem approach (EA) to management. Epibenthos from trawl catches, used in annual assessments of commercial fish stocks, was identified and measured on-board. The 2011 dataset present the baseline mapping for monitoring and included 354 taxa (218 to species level) analysed with multivariate statistical methods. This revealed four main megafaunal regions: southwestern (SW), banks/slopes in southeast and west (SEW), northwestern (NW), and northeastern (NE) which were significantly related to depth, temperature, salinity, and number of ice-days. The SW region was dominated by filter-feeders (sponges) in the inflow area of warm Atlantic water while the deeper trenches had a detritivorous fauna (echinoderms). In the SEW region, predators (sea stars, anemones and snow crabs) prevailed together with filtrating species (sea cucumber and bivalves) within a mosaic of banks and slopes. Plankton-feeding brittlestars were common in the NW and NE region, but with increasing snow crab population in NE. Climate change, potentially expanding trawling activity, and increasing snow and king crab populations might all have impacts on the benthos. Benthos should therefore be a part of an integrated assessment of a changing sea, and national agencies might consider adding benthic taxonomic expertise on-board scientific research vessels to identify the invertebrate "by-catch" as part of routine trawl surveys.
    Print ISSN: 1054-3139
    Electronic ISSN: 1095-9289
    Topics: Biology , Geosciences , Physics
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  • 9
  • 10
    Publication Date: 1989-01-01
    Print ISSN: 0025-3162
    Electronic ISSN: 1432-1793
    Topics: Biology
    Published by Springer
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