ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • Elsevier  (105,988)
  • 2010-2014  (105,988)
  • 2010  (105,988)
Collection
Keywords
Publisher
Language
Years
Year
  • 1
    facet.materialart.
    Unknown
    Toxicity of proton–metal mixtures in the field: Linking stream macroinvertebrate species diversity to chemical speciation and bioavailability (2010)
    Elsevier
    Details
    Publication Date: 2023-11-29
    Description: Understanding metal and proton toxicity under field conditions requires consideration of the complex nature of chemicals in mixtures. Here, we demonstrate a novel method that relates streamwater concentrations of cationic metallic species and protons to a field ecological index of biodiversity. The model WHAM-FTOX postulates that cation binding sites of aquatic macroinvertebrates can be represented by the functional groups of natural organic matter (humic acid), as described by the Windermere Humic Aqueous Model (WHAM6), and supporting field evidence is presented. We define a toxicity function (FTOX) by summing the products: (amount of invertebrate-bound cation) × (cation-specific toxicity coefficient, αi). Species richness data for Ephemeroptera, Plecoptera and Trichoptera (EPT), are then described with a lower threshold of FTOX, below which all organisms are present and toxic effects are absent, and an upper threshold above which organisms are absent. Between the thresholds the number of species declines linearly with FTOX. We parameterised the model with chemistry and EPT data for low-order streamwaters affected by acid deposition and/or abandoned mines, representing a total of 412 sites across three continents. The fitting made use of quantile regression, to take into account reduced species richness caused by (unknown) factors other than cation toxicity. Parameters were derived for the four most common or abundant cations, with values of αi following the sequence (increasing toxicity) H+ 〈 Al 〈 Zn 〈 Cu. For waters affected mainly by H+ and Al, FTOX shows a steady decline with increasing pH, crossing the lower threshold near to pH 7. Competition effects among cations mean that toxicity due to Cu and Zn is rare at lower pH values, and occurs mostly between pH 6 and 8.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER (OCEANREP)
  • 2
    facet.materialart.
    Unknown
    The toxicity of ozone-produced oxidants to the Pacific White Shrimp Litopenaeus vannamei (2010)
    Elsevier
    Details
    Publication Date: 2023-11-08
    Description: In marine recirculating aquaculture systems ozone, as a strong oxidant, is often used to improve water quality by reducing the pathogen load and removing inorganic and organic wastes. However, mainly when disinfection of recirculating water is desired, high ozone dosage is required, which may lead to toxicity problems for the cultured species. Acute toxicity of ozone-produced oxidants (OPO) to juvenile Pacific white shrimp, Litopenaeus vannamei, was assessed by determining the medium lethal concentration (LC50). Shrimp were exposed to a series of OPO concentrations for 96 h. Toxicity was analysed using standard probit regression. The 24, 48, 72 and 96 h LC50 values were 0.84, 0.61, 0.54 and 0.50 mg/l chlorine equivalent, respectively. A safe level for residual oxidant concentration was calculated and further verified by chronic exposure experiments. While long-term exposure of juvenile white shrimp to an OPO concentration of 0.06 mg/l revealed no observable effect, long-term exposures to 0.10 and 0.15 mg/l induced incidence of soft shell syndrome which led to mortalities due to cannibalism. Thus, an OPO concentration of 0.06 mg/l is suggested to be the maximum safe exposure level for rearing juvenile L. vannamei. Furthermore, we proved this safe level to be sufficient to control and reduce bacterial biomass in the recirculating process water.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER (OCEANREP)
  • 3
    facet.materialart.
    Unknown
    Parameter optimization and uncertainty analysis in a model of oceanic CO2 uptake using a hybrid algorithm and algorithmic differentiation (2010)
    Elsevier
    Details
    Publication Date: 2023-11-03
    Description: Methods and results for parameter optimization and uncertainty analysis for a one-dimensional marine biogeochemical model of NPZD type are presented. The model, developed by Schartau and Oschlies, simulates the distribution of nitrogen, phytoplankton, zooplankton and detritus in a water column and is driven by ocean circulation data. Our aim is to identify parameters and fit the model output to given observational data. For this model, it has been shown that a satisfactory fit could not be obtained, and that parameters with comparable fits can vary significantly. Since these results were obtained by evolutionary algorithms (EA), we used a wider range of optimization methods: A special type of EA (called quantum-EA) with coordinate line search and a quasi-Newton SQP method, where exact gradients were generated by Automatic/Algorithmic Differentiation. Both methods are parallelized and can be viewed as instances of a hybrid, mixed evolutionary and deterministic optimization algorithm that we present in detail. This algorithm provides a flexible and robust tool for parameter identification and model validation. We show how the obtained parameters depend on data sparsity and given data error. We present an uncertainty analysis of the optimized parameters w.r.t. Gaussian perturbed data. We show that the model is well suited for parameter identification if the data are attainable. On the other hand, the result that it cannot be fitted to the real observational data without extension or modification, is confirmed. (C) 2010 Elsevier Ltd. All rights reserved.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER (OCEANREP)
  • 4
    facet.materialart.
    Unknown
    Development and evaluation of a fluorescence microplate assay for quantification of heparins and other sulfated carbohydrates (2010)
    Elsevier
    Details
    Publication Date: 2023-07-19
    Description: Due to their complex composition, quantification of heparins is difficult. On the one hand there are many biological tests, which only indirectly detect effects of the antithrombin-binding material. On the other hand direct quantitative methods are available but they are often insensitive, challenging, time-consuming or expensive. The aim of this study was to develop a sensitive, rapid, simple as well as inexpensive direct quantification assay suitable for routine analysis. Based on Polymer-H, a novel heparin complexing, fluorescent labeled synthetic polymer (λ(ex) 320 nm, λ(em) 510 nm), a microplate assay was developed and optimized. The specificity of the assay was evaluated by structure–assay response relationships studies using structurally defined glucan sulfates, heparins, and other natural and synthetic sulfated carbohydrates. The fluorescence intensity of Polymer-H (7.5 μg/ml) showed to be concentration-dependently amplified by heparins as well as by other sulfated carbohydrates. The best sensitivity, accuracy and linearity were observed in a range from 0.63 to 5.0 μg/ml heparins. No differences in the fluorescence between various heparins were observed, so that only one calibration curve is needed. In addition, all types of carbohydrates with a degree of sulfation (DS) 〉 ∼1.2 and a Mr 〉 3000 can be quantified as well. By own calibration curves also other sulfated carbohydrates like fondaparinux or other glycosaminoglycans (DS 〉 0.4) can be determined.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER (OCEANREP)
  • 5
    facet.materialart.
    Unknown
    Diel Vertical Migration Behaviour of the Northern Krill (Meganyctiphanes norvegica Sars) (2010)
    Elsevier
    Details
    Publication Date: 2023-06-06
    Description: The prototype of Meganyctiphanes norvegica diel vertical migration (DVM) behaviour comprises ascent around dusk, feeding near the surface at night, and descent at dawn, explained as a trade-off between feeding and predator avoidance in an environment where both food and risk of predation is highest near surface. Light is the proximate cue, and daytime distribution is deeper in clear waters and sunny weather and nocturnal distributions deeper in moonlight. However, both internal state and external factors further affect and modify the diel migration pattern. While Meganyctiphanes migrates in synchrony to the surface at sunset, part of the population may descend soon after the ascent with individuals re-entering upper layers throughout the night. This has been explained with hungry individuals being prone to take larger risks and hence stay shallower, while satiated individuals seek shelter at depth. Females migrate closer to the surface than males of equivalent size, possibly due to their greater demand for energy to fuel egg production. Freshly moulted M. norvegica remain at depth throughout the diel cycle. This has been related to the fact that that krill do not feed during moulting, to reduced swimming capacity, and as a mechanism to avoid cannibalism whilst in a vulnerable condition. In some locations large parts of the population remain at depth at night. Such behaviour may incur access to demersal food sources, provide avoidance of predators, or can be a means to avoid horizontal transport to adjacent, unfavourable areas. Environmental gradients can arrest migrations of M. norvegica, yet the effect of physics is not always distinguished from associated biological properties, like subsurface maxima of phytoplankton located at pycnocline boundaries. Deeper nocturnal distribution when predators were abundant has been reported, and krill may adjust their distribution upwards when exposed to deep-living predators. Instantaneous escape to approaching predators is a common component of the anti-predator repertoire of Meganyctiphanes. Occasionally reported schooling behaviour that overrides normal DVM behaviour may serve anti-predation purposes, as well as being related to reproduction. M. norvegica can remain within confined areas, often defined by the bottom topography, even when exposed to strong currents. Behaviourally mediated retention may be accomplished by vertical migration in depth-stratified flows, but evidence for active use of DVM for the purpose of retention is so far circumstantial among M. norvegica. In several instances, large aggregations of krill that repeatedly occur in the same location appear to be accidental consequences of krill vertical migration behaviour interacting with the mean circulation and bottom topography, rather than representing active retention behaviour.
    Type: Book chapter , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER (OCEANREP)
  • 6
    facet.materialart.
    Unknown
    Parameterising meso-scale eddy momentum fluxes based on potential vorticity mixing and a gauge term (2010)
    Elsevier
    Details
    Publication Date: 2023-03-09
    Description: Meso-scale fluctuations are known to drive large-scale zonal flows in the ocean, a mechanism which is currently missing in non-eddy-resolving ocean models. A closure for meso-scale eddy momentum fluxes is evaluated in a suite of idealised eddying channel models, featuring eddy-driven zonal jets. It is shown how the appearance of zonal jets, which act as mixing barriers for turbulent exchange, and reduced lateral diffusivities are linked in a natural way by implementing mixing of potential vorticity and using a gauge term to insure that no spurious forces are introduced. It appears, therefore, possible to parameterise the appearance of zonal jets and its effect on the ventilation of interior ocean basins in non-eddy-resolving, realistic ocean models.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER (OCEANREP)
  • 7
    facet.materialart.
    Unknown
    Contribution of phagotrophy versus autotrophy to Prymnesium parvum growth under nitrogen and phosphorus sufficiency and deficiency (2010)
    Elsevier
    Details
    Publication Date: 2023-02-15
    Description: Laboratory experiments were conducted to test the effects of nitrogen (N) and phosphorus (P) sufficiency and deficiency on mixotrophy in Prymnesium parvum (Haptophyta). P. parvum was grown with and without algal prey (Rhodomonas salina) and observed for 120 h. Detection and enumeration of cells containing food vacuoles with prey (i.e. phagotrophy) was based on flow cytometric detection of fluorescence of an acidotropic probe. Overall, the presence of R. salina increased phagotrophy in P. parvum suggesting that, at least in this strain of P. parvum, the presence of suitable prey can stimulate phagotrophic behavior in P. parvum. Feeding frequency (the percentage of P. parvum cells containing food vacuoles in a given time) was significantly higher under N and P deficiency than in the nutrient-sufficient treatments. A nutrient budget constructed from the data indicated that ingestion of organic matter (OM) supplied with 78 ± 7% of the N (3.9 ± 0.3 μM) incorporated by P. parvum in the N-deficient treatment, and 45 ± 9% of the P (0.3 ± 0 μM) acquired in the P-deficient cultures. Even under nutrient sufficiency, ingestion of OM was estimated to have supplied 43 ± 16% of the N and 48 ± 16% of the P incorporated into P. parvum cells. Phagotrophy was observed even in the NP-sufficient cultures (non-axenic mixed and monocultures), although P. parvum cells did not lose their photosynthetic capability, suggesting that phagotrophy is probably a permanent nutritional adaptation to this species. The ingestion of organic nutrients played an important role in P. parvum growth, being a reliable source of nutrition for P. parvum inorganic nutrient limitation, and could explain its capabilities to form persistent blooms.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER (OCEANREP)
  • 8
    facet.materialart.
    Unknown
    Human peopling of Italian intramontane basins: The early Middle Pleistocene site of Pagliare di Sassa (L’Aquila, central Italy) (2010)
    Elsevier
    Details
    Publication Date: 2022-06-09
    Description: Multidisciplinary investigations at Pagliare di Sassa (L’Aquila, central Italy) suggest that the local succession accumulated from the late Early to the early Middle Pleistocene in a lacustrine environment. In the upper part, clastic sediments are part of an alluvial fan prograding into the lake, grading to a braided fluvial system. The pollen record confirms that a significant glacial phase occurred just before the onset of the Jaramillo inversion. These data, coupled with evidence from the nearby but earlier Madonna della Strada sequence, allow reconstruction of part of the environmental evolution of L’Aquila basin before the Jaramillo Subchron. The mammal species of Pagliare di Sassa include Stephanorhinus hundsheimensis, mostly of open environments, already present at Madonna della Strada. The faunal turnover characterizing the Early to Middle Pleistocene transition is indicated by the appearances of taxa typical of the Italian early to middle Galerian faunas, such as Praemegaceros verticornis, together with Megaloceros savini. The occurrence of Mimomys savini together with Microtus ex gr. Microtus hintonigregaloides suggests that this assemblage is earlier than the Isernia La Pineta fauna. A flint implement and a fragmentary herbivore femur with impact scars probably linked to human activity give evidence of the human peopling of intramontane basins of the Apennine chain since the early Middle Pleistocene.
    Description: Published
    Description: 170-178
    Description: 2.2. Laboratorio di paleomagnetismo
    Description: JCR Journal
    Description: restricted
    Keywords: Paleomagnetism ; Pleistocene ; L'Aquila Plain ; 04. Solid Earth::04.05. Geomagnetism::04.05.05. Main geomagnetic field
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER (OA)
  • 9
    facet.materialart.
    Unknown
    Distribution of squid and fish in the pelagic zone of the Cosmonaut Sea and Prydz Bay region during the BROKE-West campaign (2010)
    Elsevier
    In:  Deep Sea Research Part II: Topical Studies in Oceanography, 57 (9-10). pp. 956-967.
    Details
    Publication Date: 2021-08-30
    Description: The composition and distribution of squid and fish collected by Rectangular Midwater Trawls in the upper 200 m were investigated during the BROKE-West (Baseline Research on Oceanography, Krill and the Environment-West) survey (January-March 2006) in CCAMLR Subdivision 58.4.2 of the Southern Ocean. A total of 332 individuals were collected, with the most abundant fish species being Pleuragramma antarcticum (34%), Notolepis coatsi (27%) and Electrona antarctica (26%); and the most abundant squid being Galiteuthis glacialis (64%). Abundances of all species were among the lowest recorded using this type of gear. Cluster analysis revealed two distinct communities: a notothenioid-dominated coastal community and an oceanic community dominated by mesopelagic fish and squid. Environmental factors related to this segregation were explored using Redundancy Analysis (RDA). The notothenioid P. antarcticum was associated with shallow areas with high chlorophyll a concentrations. Larval stages of E. antarctica, N. coatsi and G. glacialis were found over deeper water and were positively correlated with higher temperatures and a deeper-reaching mixed layer. Postmetamorphic stages of E. antarctica were caught mostly after sunset and were negatively correlated with solar elevation. The observation of higher densities in the eastern part of the sampling area reflects a temporal rather than a geographical effect. Samples of the three most abundant fishes, E. antarctica, P. antarcticum and N. coatsi, were analysed for gut content. All species fed on a variety of mesozooplankton including copepods, amphipods and euphausiids, which is consistent with previous reports on similar life stages. Mean body energy density was highest for E. antarctica (27 kJ g-1), while it was similar for P. antarcticum and N. coatsi (22 kJ g-1). The high energy content emphasizing the importance as a food resource for top predators in the Southern Ocean.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER (OCEANREP)
  • 10
    facet.materialart.
    Unknown
    Life history of the deep-sea cephalopod family Histioteuthidae in the western Mediterranean (2010)
    Elsevier
    In:  Deep Sea Research Part I: Oceanographic Research Papers, 57 (8). pp. 999-1008.
    Details
    Publication Date: 2021-08-27
    Description: The life cycle of the two species of the deep-sea family Histioteuthidae inhabiting the Mediterranean Sea (Histioteuthis reversa and Histioteuthis bonnellii) was studied from monthly samples taken throughout the year during daytime hours by bottom trawl gears. A small sample of individuals found floating dead on the sea surface was also analyzed. Both species were caught exclusively on the upper slope at depths greater than 300 m. Their frequency of occurrence increased with depth and showed two different peaks, at 500–600 m and 600–700 m depth in H. bonnellii and H. reversa, respectively, which might indicate spatial segregation. Maturity stages were assigned using macroscopic determination and confirmed with histological analyses. Although mature males were caught all year round, no mature females were found, which suggests that their sexual maturation in the western Mediterranean takes place deeper than the maximum depth sampled (800 m). In fact, the increase in mean squid size with increasing depth in H. reversa indicates an ontogenetic migration to deeper waters. The individuals of both species found floating dead on the sea surface were spent females which had a relatively large cluster of small atresic eggs and a small number of remaining mature eggs scattered in the ovary and mantle cavity. The sizes of these females were clearly larger than the largest individuals caught with bottom trawls. A total of 12 and 7 different types of prey, belonging to three major taxonomic groups (crustaceans, osteichthyes and cephalopods), were identified in the stomach contents of H. reversa and H. bonnellii, respectively. In both species fishes were by far the main prey followed by crustaceans, whereas cephalopods were found only occasionally. The preys identified, mainly myctophids and natantian crustaceans, indicate that both histioteuthids base their diet on pelagic nictemeral migrators.
    Type: Article , PeerReviewed
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER (OCEANREP)
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...