julilili42/papers huggingface dataset:
Paleoclimatic and paleoenvironmental changes in the Pantanal region during the Holocene based on speleothem records
2023-02-22

The Pantanal is a large region located in the central parts of South America (140,000 km2) with a unique climate and vegetation setting. This region is subjected to seasonal floods, which makes the Pantanal one of the most important wetlands on the planet. In this region occur transitions between different biomes, such as the Amazon Forest, Cerrado (Brazilian Savanna), and Atlantic Forest, located to the North, East, and South of this region, respectively. The area also serves as a moisture pathway for the South American Summer Monsoon (SASM), which connects the Amazon Basin with the La Plata Basin. The two major drainage basins of South America. Due to the complex hydrology of the rivers and lakes of this region, it is necessary to combine multiple proxy archives from different parts of the Pantanal basin to understand its climate and vegetation evolution during the Holocene.Here we present isotope records from stalagmites collected at sites located at the northern and southern borders of the Pantanal. Hiatuses in speleothem deposition during the mid-Holocene identified in several stalagmites indicate overall dry conditions in the region at this period. However, the drier conditions recorded in the northern portion of the basin precede similar conditions in the South by approximately two thousand years. Furthermore, summer insolation seems to drive the intensity of the SASM at the North Pantanal, while its influence is weaker in the southern part. During the late Holocene, this establishes a moisture gradient between a wetter North and drier South. Our record also shows a strong multidecadal to centennial variability, which was probably responsible for the high hydrology complexity of the rivers of the Pantanal, which are subject to seasonal floods and migration of its channels and tributaries.
Diabetes in all hospitalized cases in Germany 2015–2019 and impact of the first COVID-19 year 2020
2023-02-22

Objective To analyze the proportion of diabetes among all hospitalized cases in Germany between 2015 and 2020. Methods Using the nationwide Diagnosis-Related-Groups statistics, we identified among all inpatient cases aged ≥ 20 years all types of diabetes in the main or secondary diagnoses based on ICD-10 codes, as well all COVID-19 diagnoses for 2020. Results From 2015 to 2019, the proportion of cases with diabetes among all hospitalizations increased from 18.3% (3.01 of 16.45 million) to 18.5% (3.07 of 16.64 million). Although the total number of hospitalizations decreased in 2020, the proportion of cases with diabetes increased to 18.8% (2.73 of 14.50 million). The proportion of COVID-19 diagnosis was higher in cases with diabetes than in those without in all sex and age subgroups. The relative risk (RR) for a COVID-19 diagnosis in cases with vs without diabetes was highest in age group 40–49 years (RR in females: 1.51; in males: 1.41). Conclusions The prevalence of diabetes in the hospital is twice as high as the prevalence in the general population and has increased further with the COVID-19 pandemic, underscoring the increased morbidity in this high-risk patient group. This study provides essential information that should help to better estimate the need for diabetological expertise in inpatient care settings.
Determining SISALv2-speleothem growth rates during the Holocene
2023-02-22

Speleothems are terrestrial paleoclimate archives that occur abundantly in the low and mid latitudes. They archive changes in the past hydroclimate in many ways, including the rate of calcium carbonate accumulation &amp;#8211; their growth rate. However, determining speleothem growth rates, and in particular growth rate changes, is challenging due to speleothem inherent features such as growth hiatuses, and large and abrupt growth rate changes. Low dating resolution poses an additional problem, as the U/Th measurements that allow for precise dating are time-consuming and expensive.Here, we analyze speleothem growth rates during the Holocene &amp;#8211; an ideal period for method testing due to the high abundance of speleothem records in the SISALv2 database. In particular, we compare speleothem growth rates in the early (12-8 kyr BP), mid (8-4 kyr BP) and the late Holocene (4-0 kyr BP). Using synthetically-modelled stalagmites, we test the strengths and weaknesses of state-of-the-art age-depth modelling methods to determine a set of necessary requirements to quantify speleothem growth rates and growth rate changes. Using these, we find slightly higher growth rates in the early Holocene within speleothems that cover at all periods. Comparing growth rates of speleothems that cover only one of the respective periods in the Holocene did not distinguish any period of highest or lowest growth rate. Detailed regional studies and comparison to model data are used to further interpret these results. Reliably determining growth rate changes in the Holocene may help in further understanding and characterizing hydroclimate changes as archived in speleothems also beyond the Holocene.
Pleistocene climatic variability in eastern Africa influenced hominin evolution: the 620,000-year climate record from Chew Bahir
2023-02-22

As a contribution towards a regional environmental context of human-climate interactions, the ICDP co-funded Chew Bahir Drilling Project, a part of the HSPDP (Hominin Sites and Paleolakes Drilling Project), recovered ~280-m long cores of sedimentary strata through continental scientific drilling in southern Ethiopia. The fluvio-lacustrine coring locality in the Chew Bahir basin is situated near key archaeological and paleoanthropological sites, such as the Omo-Kibish where the Omo 1 and 2 Homo sapiens fossils were recovered.Here we present the 620,000-year environmental record from Chew Bahir that provides an extraordinary opportunity to examine the potential influence of climate variability on hominin evolution, cultural innovation and dispersal during the Middle to Late Pleistocene. The near-continuous Chew Bahir record documents 13 environmental episodes that differ in length and character, potentially inducing habitat changes influencing hominin biological and cultural transformation. We infer that long-lasting and relatively stable humid conditions from ~620,000&amp;#8211;275,000 years BP (Episodes 1&amp;#8211;6) were interrupted by several abrupt and extreme hydroclimatic oscillations. This phase coincided with the appearance of high anatomical diversity in hominin groups. During Episodes 7&amp;#8211;9 (~275,000&amp;#8211;60,000 years BP), a pronounced pattern of climatic cyclicity was paralleled by the gradual transition from Acheulean to Middle Stone Age technologies, the emergence of H. sapiens in eastern Africa, and a key phase of human social and cultural innovation. Episodes 10&amp;#8211;12 (~60,000&amp;#8211;10,000 years BP), marked by high-frequency climate oscillations, is contemporaneous with the global dispersal of H. sapiens, facilitated by continued technological innovation and the alignment of humid pulses between eastern Africa and the eastern Mediterranean.Prospectively, the Chew Bahir record represents a crucial component for the Middle and Late Pleistocene in the ongoing efforts of the scientific community (future and upcoming ICDP-funded projects) to address questions in Africa &amp;#160;across four topical core areas: paleoclimate, paleoenvironment, basin evolution, and modern lake systems.
Concentrative drop impacts by a bunch of canopy drips: hotspots of soil erosion in forest
2023-02-22

Soil erosion induced by rainwater in forest ecosystems is mainly determined by throughfall kinetic energy (TKE) and ground vegetation cover. TKE is determined by raindrop size and velocity as well as precipitation amounts. Lateral canopy water flow paths can create localized concentrations of throughfall as impact points with considerable high TKE. At structurally mediated woody surface drip points notably bigger canopy drips can thus be formed under forest canopy. It is also assumed that TKE per 1mm rainfall amount (i.e., unit TKE) at impact locations is considerably higher than that at general locations due to increased rain drop sizes, resulting in a higher risk of soil erosion. However, the TKE and subsequent splash erosion potential at these impact locations have rarely been described in the previous literature and have not been quantified yet. The objectives of this study are (1) to evaluate the intensity of TKE and unit TKE at an impact location and (2) to compare those with general locations and freefall kinetic energy. We measured TKE using splash cups at seven points under a beech tree in a cool temperate forest, Japan, during five rainfall events in each leafed and leafless season. Five splash cups were further installed at an open area outside the forest as a reference. A rainfall collector was installed next to each splash cup, and throughfall at each point was quantified. TKE at the impact location (9142 &amp;#177; 5522 J m-2) was 15.2 times higher than that at general locations under beech (601 &amp;#177; 495 J m-2) and 49.7 times higher than at the open area (184 &amp;#177; 195 J m-2). The ratio of TKE at the impact location to those at general locations was higher in the leafless season. Unit kinetic energy at the impact location (39.2 &amp;#177; 23.7 J m-2 mm-1) was higher than those at general locations (22.0 &amp;#177; 12.7 J m-2 mm-1) and at the open area (4.5 &amp;#177; 3.5 J m-2 mm-1). The branch height at the impact location was lower than most areas at general locations, suggesting that higher unit TKE was induced by a bigger drop size. Our results imply that big-sized canopy drips in addition to intense throughfall amount generated at specific structurally-mediated points of the branch surface contribute far above the average to the erosion potential under the forest.
Horizontal and vertical slab tearing as different stages of a self-sustaining process developing in a non-collisional setting with oblique subduction
2023-02-22

Slab break-off is usually referred to as an early collisional process driven primarily by the slowing of the subduction rate as negatively buoyant oceanic lithosphere detaches from positively buoyant continental lithosphere that is attempting to subduct. In this context, slab tearing (or slab break-off propagation) is traditionally attributed to continental corner dynamics, when the subducting plate first detaches in the area of continental collision and then the slab window opens toward the adjacent segment of the convergence boundary, where ocean-continent subduction continues. Another important process, previously thought to be independent of slab break-off and horizontal slab tearing, is a fragmentation of the subducting slab along vertical planes perpendicular to the convergence direction. Previous numerical studies have linked this vertical slab tearing to pre-existing weakness within the subducting plate and/or abruptly changing convergence rates along the trench.In our study, we use a 3D thermo-mechanical numerical approach to study slab tearing in a non-collisional geodynamic context. The effects of subduction obliquity angle, age of oceanic slab, and partitioning of boundary velocities have been investigated. We show, for the first time, that horizontal and vertical slab tearing are different stages of the same process, which can develop in a self-sustained manner in a non-collisional environment of oblique ocean-continent subduction. Even with an initially absolutely homogeneous oceanic plate and laterally unchanging and temporally constant boundary velocities, the obliquity of the active margin appears to be a sufficient factor to trigger complex system evolution, which includes the transition from horizontal to vertical slab tearing along with additional processes such as retreat and rotation of the trench, decoupling of the overriding and downgoing plates by upwelling asthenosphere in the mantle wedge (also termed &amp;#8220;delamination&amp;#8221;), initiation of new subduction, and formation of a transform fault.Our results show striking similarities with several features &amp;#8211; such as trench curvature, subduction zone segmentation, magmatic production, lithospheric stress/deformation fields, and associated topographic changes &amp;#8211; observed in many subduction zones (e.g., Marianas, New Hebrides, Mexico, Calabrian).
LGM ice extent and deglaciation history in the Gurktal and Lavantal Alps (Eastern European Alps): first constraints from 10Be surface exposure dating of glacially polished quartz veins
2023-02-22

Compared to the Western European Alps, the ice extent during the Last Glacial Maximum (LGM) and the subsequent deglaciation history of the Eastern Alps east of the Tauern Window remains less well constrained. Also, considerable discrepancies exist between the mapped LGM ice margin (Ehlers and Gibbard, 2011; van Husen, 2004, 2011) and the ice extent predicted by ice-sheet models (Seguinot et al., 2018). Here we present the first 10Be surface exposures ages from two regions east of the Tauern window (Gurktal and Lavantal Alps), which provide constraints on the LGM ice extent and the deglaciation history (W&amp;#246;lfler et al., 2022). Our results show that the deglaciation of the Gurktal Alps occurred between 16-14 ka, which agrees with the predictions from ice-sheet models and implies that the LGM ice cover was greater than mapped. This finding also supported by our analysis of high-resolution DEMs that revealed glacially streamlined ridges and macroscale glacial striations consistent with modelled ice flow directions (Seguinot et al., 2018). In contrast, the 10Be ages from the Lavantal Alps located farther east are either LGM in age or pre-date the LGM, indicating that these regions were ice-free or only partially covered by LGM ice. Based on these results, our future investigations will aim at obtaining more age data from the Eastern Alps to refine the location of the LGM ice margin and the deglaciation history, which is also crucial for climate-evolution and postglacial-rebound models.&amp;#160;ReferencesEhlers J, Gibbard PL, Hughes PD (2011) Quaternary glaciations - Extent and chronology. A closer look. Developments in Quaternary Science 15.Seguinot J., Ivy-Ochs S, Jouvet G, Huss M, Funk M, Preusser F. (2018) Modelling last glacial cycle ice dynamics in the Alps. The Cryosphere 12: 3265&amp;#8211;3285.van Husen D. (2004) Quaternary glaciations in Austria. In: Quaternary Glaciations: Extent and Chronology Part I: Europe, Ehlers J, Gibbard PL (eds). Elsevier: London: 1&amp;#8211;13.van Husen D (2011) Quaternary Glaciations in Austria. In Quaternary Glaciations &amp;#8211; Extent and Chronology: A Closer Look, Ehlers J, Gibbard PL, Hughes PD (eds). 15: 15&amp;#8211;28.W&amp;#246;lfler A, Hampel A, Dielforder A, Hetzel R, Glotzbach C (2022) LGM ice extent and deglaciation history in the Gurktal and Lavantal Alps (eastern European Alps): first constraints from 10Be surface exposure dating of glacially polished quartz veins, Journal of Quaternary Science&amp;#160; 37: 677-687. https:// doi.org/10.1002/jqs.3399
Holocene human-environmental interactions and seismic activity in a Late Bronze to Early Iron Age settlement center in the southeastern Caucasus
2023-02-22

Long-term human-environmental interactions in naturally fragile drylands are an actual topic of geomorphological and geoarchaeological research. Furthermore, many prehistoric societies in drylands were also affected by seismic activity. The semi-arid Shiraki Plain in the tectonically active southeastern Caucasus is currently covered by steppes and largely devoid of settlements. However, numerous Late Bronze to Early Iron Age city-type fortified settlements suggest early state formation between ca. 3.2 &amp;#8211; 2.5 ka that abruptly ended after that time. A paleolake was suggested for the lowest plain, and nearby pollen records suggest forest clearcutting of the upper altitudes under a more humid climate during the Late Bronze/Early Iron Ages. Furthermore, also an impact of earthquakes on regional Early Iron Age settlements was suggested. However, regional paleoenvironmental changes and paleoseismicity were not systematically studied so far. We combined geomorphological, sedimentological, chronological, paleoecological and hydrological modelling data to reconstruct regional Holocene paleoenvironmental changes in the Shiraki Plain, and identify possible natural and anthropogenic causes as well as possible seismic events during the Late Bronze/Early Iron Ages. Our results show a balanced to negative Early to Mid-Holocene water balance probably caused by forested upper slopes. Hence, no lake but an incipient Chernozem developed in the lowest plain. Following, Late Bronze/Early Iron Age forest clear-cutting obviously caused lake formation and the deposition of lacustrine sediments derived from intensive soil erosion. Subsequently, regional aridification obviously caused slow lake desiccation. Remains of freshwater fishes indicate that the lake potentially offered valuable ecosystem services for regional prehistoric societies even during the desiccation period. Finally, colluvial coverage of the lake sediments during the last centuries could have been linked with hydrological extremes during the Little Ice Age. Our study demonstrates that the Holocene hydrological balance of the Shiraki Plain was and is situated near a major hydrological threshold, making the landscape very sensitive to also small-scale human or natural influences with serious consequences for local societies. Furthermore, seismites in the studied sediments do not indicate an influence of earthquakes on the main and late phases of Late Bronze/Early Iron Age settlement. Altogether, our study underlines the high value of multi-disciplinary approaches to investigate long-term human-environmental interactions and paleoseismicity in drylands on millennial to centennial time scales.
Fish starved to death by Mediterranean water-column stratification and high salinity in pre-evaporitic Messinian
2023-02-22

The restriction of the Mediterranean&amp;#8211;Atlantic marine connection over the Messinian stage, which led to a salinity crisis and the deposition of the youngest salt giant on Earth, impacted the composition and structure of marine biota in unprecedented ways, but its effects on the biological functions of marine organisms remains unchartered territory. By analyzing the stable oxygen and carbon isotopic composition of the otoliths of two carefully selected fish species, a pelagic (surface) and a benthic (bottom-dwelling) one, we were able to infer not only the sea surface and bottom salinity and oxygenation conditions, but also the fishes&amp;#8217; metabolic response to the paleoceanographic changes in the eastern Mediterranean from 7.2 to 6.5 Ma. The high salinity and stratification of the Mediterranean water column during this interval hampered the ability of the marine fishes to grow, particularly those dwelling in the sea bottom. A first event (6.82&amp;#8211;6.81 Ma) of high temperature and salinity induced an increase in the metabolism of fishes across the water column, meaning that they consumed and respired more. Subsequent warming, increased salinity and stratification at 6.70&amp;#8211;6.69 Ma further intensified the environmental stress for bottom-water fishes. To cope with these extreme conditions at the sea floor, benthic fishes show increased metabolic carbon despite low food availability, which implies that fishes metabolized (i.e. consumed) their own tissue to survive. The disappearance of benthic fishes in the study area after 6.8 Ma further reinforces this conclusion. Our study promotes the importance of otoliths stable isotopic analyses as tools for reconstructing complex paleoenvironmental histories.
Temperature and precipitation reconstruction for Last Glacial Central Europe reveals new insights into continental climate dynamics
2023-02-22

Over the last glacial period, the climate of the Northern Hemisphere experienced numerous abrupt variations on millennial to centennial timescales known as Dansgaard-Oeschger events. These events, characterised by rapid warming at the beginning of interstadials and gradual cooling back to stadial conditions are best documented in Greenland ice cores and North Atlantic marine records, while their propagation onto the continents and potential feedbacks are less well documented. In this context, loess palaeosol sequences in central Europe are valuable archives, often recording these climatic changes in the form of brown soils and tundra gley horizons - indicating milder interstadial conditions - intercalated with primary loess deposits reflecting cold stadial conditions.To reconstruct palaeoclimate changes at high resolution we use singular material from loess sediments: fossil earthworm calcite granules (ECG). ECGs, composed of aggregated sparite crystals formed in the calciferous earthworm glands, are secreted daily at the soil surfacemostly by Lumbricus species and experience limited vertical mixing within the loess sedimentary column. ECGs are thus an excellent terrestrial material for palaeoclimate reconstructions using stable isotopic geochemistry and radiocarbon dating. ECGs have been collected from two temporally overlapping loess-palaeosol sequences along an NNW-SSE transect in the Rhine River valley of western Germany. We present warm-season land-surface temperature and precipitation estimates at millennial timescales spanning ~ 45-22 cal kBP (late OIS 3 - OIS 2). &amp;#160;We demonstrate that OIS 3-2 climate in the Rhine Valley was significantly cooler during the warm season and overall drier with annual precipitation reduced by up to 70%, compared to the present day. Interstadials were only slightly warmer (1-4&amp;#176;C) than stadial indicating strong attenuation compared to Greenland records. In combination with mesoscale wind and moisture transport modelling we can show that this region was dominated by westerlies and thereby inextricably linked to North Atlantic climate forcing.The approach combining high-resolution age-depth modelling and geochemical proxy-based climate reconstruction can be readily adopted at other loess palaeosol sequences. We envisage a widespread application of this approach that would improve our understanding of regional variability over the European continent in response to North Atlantic climate changes over millennial to centennial timescales.
Seasonal enhanced melting under Ekström Ice Shelf, Antarctica
2023-02-22

Ice&amp;#8211;ocean interaction is crucial for the integrity of ice shelves and thus ice sheet stability. Warm ocean currents lead to enhanced basal melting of ice shelves, which is the dominant component of mass loss for the Antarctic Ice Sheet. Knowing the current melt rates and predicting those under future climate scenarios is thus of great importance. In the course of the &amp;#173;MIMO-EIS (Monitoring melt where Ice Meets Ocean) Project, we deployed a continuously measuring ApRES (Autonomous phase-sensitive Radio-Echo Sounding) device in the center of Ekstr&amp;#246;m Ice Shelf, recording an hourly time series since April 2020. The continuous time series reveals a seasonal onset of enhanced melt rates, abruptly increasing from &lt;0.5 to 2 m/a in July/August. High melt rates with around weekly to bi-weekly fluctuations last until November/December. In addition, we performed annual point measurements to determine the spatial pattern of basal melt rates. The majority of these sites show yearly averaged melt rates of &lt;0.5 m/a. These measurements allow the evaluation of future ocean-simulations and are in good agreement with satellite remote sensing estimates.