ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

Your email was sent successfully. Check your inbox.

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

Proceed reservation?

Export
Filter
  • Elsevier  (5,804,788)
  • Springer Nature  (1,070,394)
  • American Physical Society  (663,490)
  • Oxford University Press  (428,982)
Collection
Publisher
Language
Years
  • 1
    Publication Date: 2024-06-22
    Description: The Antarctic Circumpolar Current (ACC) plays a crucial role in global ocean circulation by fostering deep-water upwelling and formation of new water masses. On geological timescales, ACC variations are poorly constrained beyond the last glacial. Here, we reconstruct changes in ACC strength in the central Drake Passage in vicinity of the modern Polar Front over a complete glacial-interglacial cycle (i.e., the past 140,000 years), based on sediment grain-size and geochemical characteristics. We found significant glacial-interglacial changes of ACC flow speed, with weakened current strength during glacials and a stronger circulation in interglacials. Superimposed on these orbital-scale changes are high-amplitude millennialscale fluctuations, with ACC strength maxima correlating with diatom-based Antarctic winter sea-ice minima, particularly during full glacial conditions. We infer that the ACC is closely linked to Southern Hemisphere millennial-scale climate oscillations, amplified through Antarctic sea ice extent changes. These strong ACC variations modulated Pacific-Atlantic water exchange via the “cold water route” and potentially affected the Atlantic Meridional Overturning Circulation and marine carbon storage.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 2
    Publication Date: 2024-06-21
    Description: 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.
    Description: 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”.
    Description: In press
    Description: 108131
    Description: OSV1: Verso la previsione dei fenomeni vulcanici pericolosi
    Description: JCR Journal
    Keywords: Stromboli volcano ; Volcanic monitoring ; Data analysis ; Multiparametric geophysics ; Paroxysmal explosions ; 04.08. Volcanology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 3
    Publication Date: 2024-06-21
    Description: 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
    Type: Article , isiRev
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 4
    Publication Date: 2024-06-21
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , peerRev
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 5
    Publication Date: 2024-06-21
    Description: 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
    Type: Article , isiRev
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 6
    facet.materialart.
    Unknown
    Elsevier
    In:  EPIC3Ecological Modelling, Elsevier, 478, pp. 110278-110278, ISSN: 0304-3800
    Publication Date: 2024-06-21
    Description: 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
    Type: Article , isiRev
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 7
    Publication Date: 2024-06-21
    Description: Background: Wildfires are recognized as an important ecological component of larch-dominated boreal forests in eastern Siberia. However, long-term fire-vegetation dynamics in this unique environment are poorly understood. Recent paleoecological research suggests that intensifying fire regimes may induce millennial-scale shifts in forest structure and composition. This may, in turn, result in positive feedback on intensifying wildfires and permafrost degradation, apart from threatening human livelihoods. Most common fire-vegetation models do not explicitly include detailed individual-based tree population dynamics, but a focus on patterns of forest structure emerging from interactions among individual trees may provide a beneficial perspective on the impacts of changing fire regimes in eastern Siberia. To simulate these impacts on forest structure at millennial timescales, we apply the individual-based, spatially explicit vegetation model LAVESI-FIRE, expanded with a new fire module. Satellite-based fire observations along with fieldwork data were used to inform the implementation of wildfire occurrence and adjust model parameters. Results: Simulations of annual forest development and wildfire activity at a study site in the Republic of Sakha (Yakutia) since the Last Glacial Maximum (c. 20,000 years BP) highlight the variable impacts of fire regimes on forest structure throughout time. Modeled annual fire probability and subsequent burned area in the Holocene compare well with a local reconstruction of charcoal influx in lake sediments. Wildfires can be followed by different forest regeneration pathways, depending on fire frequency and intensity and the pre-fire forest conditions. We find that medium-intensity wildfires at fire return intervals of 50 years or more benefit the dominance of fire-resisting Dahurian larch (Larix gmelinii (Rupr.) Rupr.), while stand-replacing fires tend to enable the establishment of evergreen conifers. Apart from post-fire mortality, wildfires modulate forest development mainly through competition effects and a reduction of the model’s litter layer. Conclusion: With its fine-scale population dynamics, LAVESI-FIRE can serve as a highly localized, spatially explicit tool to understand the long-term impacts of boreal wildfires on forest structure and to better constrain interpretations of paleoecological reconstructions of fire activity.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 8
    facet.materialart.
    Unknown
    Springer Nature
    In:  EPIC3Nature Communications, Springer Nature, 13(1), pp. 6035-6035, ISSN: 2041-1723
    Publication Date: 2024-06-21
    Description: How fast the Northern Hemisphere (NH) forest biome tracks strongly warming climates is largely unknown. Regional studies reveal lags between decades and millennia. Here we report a conundrum: Deglacial forest expansion in the NH extra-tropics occurs approximately 4000 years earlier in a transient MPI-ESM1.2 simulation than shown by pollen-based biome reconstructions. Shortcomings in the model and the reconstructions could both contribute to this mismatch, leaving the underlying causes unresolved. The simulated vegetation responds within decades to simulated climate changes, which agree with pollen-independent reconstructions. Thus, we can exclude climate biases as main driver for differences. Instead, the mismatch points at a multi-millennial disequilibrium of the NH forest biome to the climate signal. Therefore, the evaluation of time-slice simulations in strongly changing climates with pollen records should be critically reassessed. Our results imply that NH forests may be responding much slower to ongoing climate changes than Earth System Models predict.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 9
    facet.materialart.
    Unknown
    Springer Nature
    In:  EPIC3International Journal of Biometeorology, Springer Nature, 68(4), pp. 1-17, ISSN: 0020-7128
    Publication Date: 2024-06-21
    Description: The Great Lakes region of North America has warmed by 1–2 °C on average since pre-industrial times, with the most pronounced changes observable during winter and spring. Interannual variability in temperatures remains high, however, due to the influence of ocean-atmosphere circulation patterns that modulate the warming trend across years. Variations in spring temperatures determine growing season length and plant phenology, with implications for whole ecosystem function. Studying how both internal climate variability and the “secular” warming trend interact to produce trends in temperature is necessary to estimate potential ecological responses to future warming scenarios. This study examines how external anthropogenic forcing and decadal-scale variability influence spring temperatures across the western Great Lakes region and estimates the sensitivity of regional forests to temperature using long-term growth records from tree-rings and satellite data. Using a modeling approach designed to test for regime shifts in dynamic time series, this work shows that mid-continent spring climatology was strongly influenced by the 1976/1977 phase change in North Pacific atmospheric circulation, and that regional forests show a strengthening response to spring temperatures during the last half-century.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 10
    Publication Date: 2024-06-21
    Description: 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
    Type: Article , isiRev
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...