ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

Ihre E-Mail wurde erfolgreich gesendet. Bitte prüfen Sie Ihren Maileingang.

Leider ist ein Fehler beim E-Mail-Versand aufgetreten. Bitte versuchen Sie es erneut.

Vorgang fortführen?

Exportieren
Filter
  • Elsevier  (5.804.788)
  • Springer  (3.531.829)
  • Institute of Physics  (1.082.725)
  • Periodicals Archive Online (PAO)  (190.459)
Sammlung
Verlag/Herausgeber
Sprache
Erscheinungszeitraum
  • 1
    Publikationsdatum: 2024-06-21
    Beschreibung: Stromboli (Italy) is an open-vent volcano with persistent explosive activity producing up to five hundred mild explosions per day. Fluctuations in explosion intensity, varying even by orders of magnitude in terms of emitted volume and their subsequent impact on the surrounding regions, sometimes occur abruptly. Consequently, identifying precursors of larger eruptive activities, particularly for more intense (paroxysmal) explosions, is challenging. In order to search for anomalies in the pre-paroxysm activity related to the summer 2019 eruption, we applied a hybrid method to the automatic analysis of geophysical and geochemical time series. This approach is based on the combination of two methods: 1. the Empirical Mode Decomposition (EMD) and 2. the Support Vector Regression (SVR). The aggregation of these two methods allowed us to identify anomalies in the patterns of the geophysical and geochemical parameters measured on Stromboli in a ten-month period including the July–August 2019 eruption. The results of this study are encouraging for an improvement of the monitoring systems and for volcano early warning applications.
    Beschreibung: This work has been supported by the INGV project Pianeta Dinamico 2023-2025 - ObseRvation, Measurement and modelling of Eruptive processes (ORME), and partially supported by the Progetto Strategico Dipartimentale INGV 2019 “Forecasting eruptive activity at Stromboli volcano: timing, eruptive style, size, intensity and duration” (FIRST, Delibera n. 144/2020; Scientific Responsibility: S.C.). Furthermore, this research has benefited from the support of Convenzione B2 DPC-INGV 2022-2024, Stromboli, Task 1.3 “Development of a unique activity index and estimation of the probability of the transition between ‘ordinary’ and ‘extraordinary’ eruptive activity”, and of the INGV project “Reti Multiparametriche”, Task A2 “Development of methods for the identification of precursors of Stromboli's paroxysms and major explosions based on multiparametric data analysis and study of possible early warning techniques”.
    Beschreibung: In press
    Beschreibung: 108131
    Beschreibung: OSV1: Verso la previsione dei fenomeni vulcanici pericolosi
    Beschreibung: JCR Journal
    Schlagwort(e): Stromboli volcano ; Volcanic monitoring ; Data analysis ; Multiparametric geophysics ; Paroxysmal explosions ; 04.08. Volcanology
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 2
    Publikationsdatum: 2024-06-21
    Beschreibung: The marine habitat beneath Antarctica’s ice shelves spans ~1.6 million km2, and life in this vast and extreme environment is among Earth’s least accessible, least disturbed and least known, yet likely to be impacted by climate-forced warming and environmental change. Although competition among biota is a fundamental structuring force of ecological communities, hence ecosystem functions and services, nothing was known of competition for resources under ice shelves, until this study. Boreholes drilled through a ~ 200 m thick ice shelf enabled collections of novel sub-ice-shelf seabed sediment which contained fragments of biogenic substrata rich in encrusting (lithophilic) macrobenthos, principally bryozoans – a globally-ubiquitous phylum sensitive to environmental change. Analysis of sub-glacial biogenic substrata, by stereo microscopy, provided first evidence of spatial contest competition, enabling generation of a new range of competition measures for the sub-ice-shelf benthic space. Measures were compared with those of global open-water datasets traversing polar, temperate and tropical latitudes (and encompassing both hemispheres). Spatial competition in sub-ice-shelf samples was found to be higher in intensity and severity than all other global means. The likelihood of sub-ice-shelf competition being intraspecific was three times lower than for open-sea polar continental shelf areas, and competition complexity, in terms of the number of different types of competitor pairings, was two-fold higher. As posited foran enduring disturbance minimum, a specific bryozoan clade was especially competitively dominant in sub-ice shelf samples compared with both contemporary and fossil assemblage records. Overall, spatial competition under an Antarctic ice shelf, as characterised by bryozoan interactions, was strikingly different from that of open- sea polar continental shelf sites, and more closely resembled tropical and temperate latitudes. This study represents the first analysis of sub-ice-shelf macrobenthic spatial competition and provides a new ecological baseline for exploring, monitoring and comparing ecosystem response to environmental change in a warming world.
    Repository-Name: EPIC Alfred Wegener Institut
    Materialart: Article , isiRev
    Format: application/pdf
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 3
    Publikationsdatum: 2024-06-21
    Beschreibung: The Qinghai-Tibet Plateau (QTP) is characterized by a vast number of frozen and unfrozen freshwater reservoirs, which is why it is also called “the third pole” of the Earth or “Asian Water Tower”. We analyzed testate amoeba (TA) biodiversity and corresponding protozoic biosilicification in lake sediments of the QTP in relation to environmental properties (freshwater conditions, elevation, and climate). As TA are known as excellent bio-indicators, our results allowed us to derive conclusions about the influence of climate warming on TA communities and microbial biogeochemical silicon (Si) cycling. We found a total of 113 TA taxa including some rare and one unknown species in the analyzed lake sediments of the QTP highlighting the potential of this remote region for TA biodiversity. 〉1/3 of the identified TA taxa were relatively small (〈30 μm) reflecting the relatively harsh environmental conditions in the examined lakes. TA communities were strongly affected by physico-chemical properties of the lakes, especially water temperature and pH, but also elevation and climate conditions (temperature, precipitation). Our study reveals climate-related changes in TA biodiversity with consequences for protozoic biosilicification. As the warming trend in the QTP is two to three times faster compared to the global average, our results provide not only deeper insights into the relations between TA biodiversity and environmental properties, but also predictions of future developments in other regions of the world. Moreover, our results provide fundamental data for paleolimnological reconstructions. Thus, examining the QTP is helpful to understand microbial biogeochemical Si cycling in the past, present, and future.
    Repository-Name: EPIC Alfred Wegener Institut
    Materialart: Article , isiRev
    Format: application/pdf
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 4
    facet.materialart.
    Unbekannt
    Elsevier
    In:  EPIC3Ecological Modelling, Elsevier, 478, pp. 110278-110278, ISSN: 0304-3800
    Publikationsdatum: 2024-06-21
    Beschreibung: With changing climate, the boreal forest could potentially migrate north and become threatened by droughts in the south. However, whether larches, the dominant tree species in eastern Siberia, can adapt to novel situations is largely unknown but is crucial for predicting future population dynamics. Exploring variable traits and trait adaptation through inheritance in an individual-based model can improve our understanding and help future projections. We updated the individual-based spatially explicit vegetation model LAVESI (Larix Vegetation Simulator), used for forest predictions in Eastern Siberia, with trait value variation and incorporated inheritance of parental values to their offspring. Forcing the model with both past and future climate projections, we simulated two areas – the expanding northern treeline and a southerly area experiencing drought. While the specific trait of ‘seed weight’ regulates migration, the abstract ‘drought resistance’ protects stands. We show that trait variation with inheritance leads to an increase in migration rate (∼ 3% area increase until 2100). The drought resistance simulations show that, under increasing stress, including adaptive traits leads to larger surviving populations (17% of threatened under RCP 4.5 (Representative Concentration Pathway)). We show that with the increase expected under the RCP 8.5 scenario vast areas (80% of the extrapolated area) of larch forest are threatened and could disappear due to drought as adaptation plays only a minor role under strong warming. We conclude that variable traits facilitate the availability of variants under environmental changes. Inheritance allows populations to adapt to environments and promote successful traits, which leads to populations that can spread faster and be more resilient, provided the changes are not too drastic in both time and magnitude. We show that trait variation and inheritance contribute to more accurate models that can improve our understanding of responses of boreal forests to global change.
    Repository-Name: EPIC Alfred Wegener Institut
    Materialart: Article , isiRev
    Format: application/pdf
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 5
    Publikationsdatum: 2024-06-21
    Beschreibung: While the influence of precession on monsoon at low latitudes through insolation forcing is well-known, the role of obliquity is still debated since its influence on the distribution of incoming solar radiation is small in these regions. In southern Africa, long marine and terrestrial sedimentary records attest of a precessional influence on the South African monsoon at orbital time scale. The obliquity signal is occasionally observed in the geological records although modeling results suggest an influence of precession and obliquity on summer monsoon. Here, we present a record of microscopic charcoal from core MD96-2098 located off Namibia covering the past 184,000 years. Our record of fire activity reveals cyclic changes at frequencies of 23, 58 and 12 kyr−1 and lacks the obliquity signal at 41 kyr−1. Changes in fire over southern Africa are interpreted as shifts in large and intense fires spreading in open-grassland savanna as a result of orbitally-driven changes in rainfall intensity associated with the South African monsoon. We show that, despite the absence of a 41 kyr obliquity imprint, the presence of 23, 58 and 12 kyr−1 frequencies likely stems from a nonlinear response of fire to precipitation controlled by a combination of precession and obliquity frequencies, supporting the influence of obliquity on the South African monsoon.
    Repository-Name: EPIC Alfred Wegener Institut
    Materialart: Article , isiRev
    Format: application/pdf
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 6
    Publikationsdatum: 2024-06-20
    Beschreibung: Ancient environmental DNA (aeDNA) data are close to enabling insights into past global-scale biodiversity dynamics at unprecedented taxonomic extent and resolution. However, achieving this potential requires solutions that bridge bioinformatics and paleoecoinformatics. Essential needs include support for dynamic taxonomic inferences, dynamic age inferences, and precise stratigraphic depth. Moreover, aeDNA data are complex and heterogeneous, generated by dispersed researcher networks, with methods advancing rapidly. Hence, expert community governance and curation are essential to building high-value data resources. Immediate recommendations include uploading metabarcoding-based taxonomic inventories into paleoecoinformatic resources, building linkages among open bioinformatic and paleoecoinformatic data resources, harmonizing aeDNA processing workflows, and expanding community data governance. These advances will enable transformative insights into global-scale biodiversity dynamics during large environmental and anthropogenic changes.
    Repository-Name: EPIC Alfred Wegener Institut
    Materialart: Article , isiRev
    Format: application/pdf
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 7
    facet.materialart.
    Unbekannt
    Elsevier
    In:  EPIC3Palaeogeography Palaeoclimatology Palaeoecology, Elsevier, 612, pp. 111380-111380, ISSN: 0031-0182
    Publikationsdatum: 2024-06-20
    Beschreibung: Relatively little is known about the relationship between the Indian summer monsoon (ISM) and the El Niño-Southern Oscillation (ENSO) on the centennial timescale during the Holocene. We present a well-dated high-resolution X-ray fluorescence (XRF) scanning record from a sediment core from Lake Qionghai on the southeastern Tibetan Plateau, which reveals the impact of ENSO activity on ISM variability. The results indicate a gradual drying of the regional climate on the sub-orbital timescale, which is in broad agreement with ISM changes controlled by Northern Hemisphere summer insolation. Additionally, centennial-scale drought events occurred at around 6230–5740, 4620–4250, 3820–3540, 3210–2440, 2180–1320, and 1000–615 cal yr B.P. and are consistent with enhanced ENSO activity, documenting the occurrence of ENSO-related drought events in the Holocene. Both ISM oscillations and ENSO variability show significant 350-yr, 500-yr, and 800-yr cyclicities, and there is a highly significant negative relationship between the ISM and ENSO at these cyclicities, indicating that a weak ISM was related to increased ENSO intensity, and vice versa. Our findings provide evidence for the modulation of ISM intensity by ENSO variability on the centennial timescale during the Holocene.
    Repository-Name: EPIC Alfred Wegener Institut
    Materialart: Article , isiRev
    Format: application/pdf
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 8
    Publikationsdatum: 2024-06-20
    Beschreibung: Since the initial discovery of the non-exponential mass fractionation (non-EMF) of Nd isotopes analysis in 2002, similar deviations from an EMF pattern have been reported for measurements of a number of isotope systems (e.g., Si, Ge, Sr, Sn, Ba, Yb, W, Os, Hg and Pb) with MC-ICP-MS. However, the previous controversial reports on the magnitude of the deviations from EMF suggest that instrumental mass bias behaviour of MC-ICP-MS is neither fully understood nor well-characterised. Consequently, the standard approach of using a mass dependent fractionation (MDF) correction model (e.g., exponential law) may lead to both inaccurate and imprecise results. In this study, we systematically characterise the instrumental mass fractionation of MC-ICP-MS using Nd isotope measurements carried out under different plasma conditions, quantified using the normalised argon index (NAI) as an estimate of plasma temperature. Our results indicate that the mass bias of MC-ICP-MS is not always a simple exponential function of mass but shows systematic deviations from an EMF behaviour, which are closely associated with decreased NAIs. As a result, the conventional exponential correction yields a 143Nd/144Nd value of 0.512257 for the reference material BHVO-2 when the NAI is low, which is 722 ppm lower than the reported value of 0.512979. By tuning the plasma to higher NAIs (higher plasma temperatures), the deviations from the EMF array are systematically attenuated and the exponential correction is able to correct for the instrumental mass bias under high NAIs. In contrast, a regression correction model for Nd isotopes is developed to account for the observed mass fractionation behaviour that does not follow EMF under low NAIs, given that the regression correction relies on the observed loglinear fractionation of different isotope pairs and does not require both isotope ratios to undergo EMF. We expect that the analytical protocol and fundamental insights gained in this study are applicable to a wide range of other isotope measurements with MC-ICP-MS.
    Materialart: Article , PeerReviewed , info:eu-repo/semantics/article
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 9
    Publikationsdatum: 2024-06-19
    Beschreibung: This chapter provides an overview of near-surface geochemical processes operating on Earth, with special emphasis placed on (i) marine weathering such as alteration and dissolution of silicates, carbonates and terrigenous riverine particles in the ocean, complemented by (ii) reverse weathering reactions leading to marine authigenic clay formation, and the impact of these phenomena on ocean alkalinity budget and the chemical and isotope composition of seawater. Model simulations of the above processes provide estimates of the global marine fluxes of major cations (Na+, K+, Mg2+, Ca2+) and alkalinity in the ocean induced by silicate weathering and dissolution of terrigenous material in seawater. Additional constraints on silicate vs. carbonate weathering, oceanic/coastal CaCO3 cycling, and paleo-seawater reconstructions are provided via the stable and radiogenic isotope systems of alkali and alkaline earth metals (Li, K, Mg, Ca, and Sr isotopes) that are discussed within the context of marine and reverse weathering in the present and past ocean. Key points • Impact of weathering processes on marine elemental cycles and the ocean alkalinity budget. • Alteration and dissolution of silicate minerals and riverine particles in the ocean quantified via thermodynamic equilibrium (PHREEQC) calculations, in seawater and top sediment settings. • Estimates of global ocean fluxes of dissolved cations (Na+ , K+ , Mg 2+ , Ca2+ ) and alkalinity induced by alteration and dissolution of terrigenous material in seawater and marine sediments. • Principles and mechanisms of isotope variability in nature (mass-dependent and radiogenic isotope effects) observed for alkali and alkaline earth metals. • Silicate vs. carbonate weathering and coastal carbon/carbonate cycling constrained via stable and radiogenic Ca and Sr, and Li isotopes. • Oceanic processes, marine carbonate chemistry (alkalinization vs. acidification), and paleo-seawater reconstructions constrained via d44 Ca, d88 Sr, d26 Mg proxies and numerical (MATLAB) modeling. • Emerging metal isotope proxies (d41 K) for silicate and reverse weathering in the ocean.
    Materialart: Book chapter , NonPeerReviewed , info:eu-repo/semantics/bookPart
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 10
Schließen ⊗
Diese Webseite nutzt Cookies und das Analyse-Tool Matomo. Weitere Informationen finden Sie hier...