@article{ToumoulinTardifBecquetDonnadieuetal.2022, author = {Toumoulin, Agathe and Tardif-Becquet, Delphine and Donnadieu, Yannick and Licht, Alexis and Ladant, Jean-Baptiste and Kunzmann, Lutz and Dupont-Nivet, Guillaume}, title = {Evolution of continental temperature seasonality from the Eocene greenhouse to the Oligocene icehouse}, series = {Climate of the past : an interactive open access journal of the European Geosciences Union}, volume = {18}, journal = {Climate of the past : an interactive open access journal of the European Geosciences Union}, number = {2}, publisher = {Copernicus}, address = {G{\"o}ttingen}, issn = {1814-9324}, doi = {10.5194/cp-18-341-2022}, pages = {341 -- 362}, year = {2022}, abstract = {At the junction of greenhouse and icehouse climate states, the Eocene-Oligocene Transition (EOT) is a key moment in Cenozoic climate history. While it is associated with severe extinctions and biodiversity turnovers on land, the role of terrestrial climate evolution remains poorly resolved, especially the associated changes in seasonality. Some paleobotanical and geochemical continental records in parts of the Northern Hemisphere suggest the EOT is associated with a marked cooling in winter, leading to the development of more pronounced seasons (i.e., an increase in the mean annual range of temperature, MATR). However, the MATR increase has been barely studied by climate models and large uncertainties remain on its origin, geographical extent and impact. In order to better understand and describe temperature seasonality changes between the middle Eocene and the early Oligocene, we use the Earth system model IPSL-CM5A2 and a set of simulations reconstructing the EOT through three major climate forcings: pCO(2) decrease (1120, 840 and 560 ppm), the Antarctic ice-sheet (AIS) formation and the associated sea-level decrease. Our simulations suggest that pCO(2) lowering alone is not sufficient to explain the seasonality evolution described by the data through the EOT but rather that the combined effects of pCO(2) , AIS formation and increased continentality provide the best data-model agreement.pCO(2) decrease induces a zonal pattern with alternating increasing and decreasing seasonality bands particularly strong in the northern high latitudes (up to 8 degrees C MATR increase) due to sea-ice and surface albedo feedback. Conversely, the onset of the AIS is responsible for a more constant surface albedo yearly, which leads to a strong decrease in seasonality in the southern midlatitudes to high latitudes (> 40 degrees S). Finally, continental areas that emerged due to the sea-level lowering cause the largest increase in seasonality and explain most of the global heterogeneity in MATR changes (1MATR) patterns. The Delta MATR patterns we reconstruct are generally consistent with the variability of the EOT biotic crisis intensity across the Northern Hemisphere and provide insights on their underlying mechanisms.}, language = {en} } @article{SmithBoers2023, author = {Smith, Taylor and Boers, Niklas}, title = {Global vegetation resilience linked to water availability and variability}, series = {Nature Communications}, volume = {14}, journal = {Nature Communications}, number = {1}, publisher = {Springer Nature}, address = {London}, issn = {2041-1723}, doi = {10.1038/s41467-023-36207-7}, pages = {11}, year = {2023}, abstract = {Quantifying the resilience of vegetated ecosystems is key to constraining both present-day and future global impacts of anthropogenic climate change. Here we apply both empirical and theoretical resilience metrics to remotely-sensed vegetation data in order to examine the role of water availability and variability in controlling vegetation resilience at the global scale. We find a concise global relationship where vegetation resilience is greater in regions with higher water availability. We also reveal that resilience is lower in regions with more pronounced inter-annual precipitation variability, but find less concise relationships between vegetation resilience and intra-annual precipitation variability. Our results thus imply that the resilience of vegetation responds differently to water deficits at varying time scales. In view of projected increases in precipitation variability, our findings highlight the risk of ecosystem degradation under ongoing climate change. Vegetation dynamics depend on both the amount of precipitation and its variability over time. Here, the authors show that vegetation resilience is greater where water availability is higher and where precipitation is more stable from year to year.}, language = {en} } @article{RepaschScheingrossHoviusetal.2022, author = {Repasch, Marisa and Scheingross, Joel S. and Hovius, Niels and Vieth-Hillebrand, Andrea and Mueller, Carsten W. and H{\"o}schen, Carmen and Szupiany, Ricardo N. and Sachse, Dirk}, title = {River organic carbon fluxes modulated by hydrodynamic sorting of particulate organic matter}, series = {Geophysical research letters}, volume = {49}, journal = {Geophysical research letters}, number = {3}, publisher = {American Geophysical Union}, address = {Washington}, issn = {0094-8276}, doi = {10.1029/2021GL096343}, pages = {11}, year = {2022}, abstract = {Rivers regulate the global carbon cycle by transferring particulate organic carbon (POC) from terrestrial landscapes to marine sedimentary basins, but the processes controlling the amount and composition of fluvially exported POC are poorly understood. We propose that hydrodynamic sorting processes modify POC fluxes during fluvial transit. We test this hypothesis by studying POC transported along a similar to 1,200 km reach of the Rio Bermejo, Argentina. Nanoscale secondary ion mass spectrometry revealed that POC was either fine, mineral-associated organic matter, or coarse discrete organic particles. Mineral-associated POC is more resistant to oxidation and has a lower particle settling velocity than discrete POC. Consequently, hydraulic sorting and downstream fining amplify the proportion of fine, mineral-associated POC from similar to 55\% to similar to 78\% over 1,220 km of downstream transit. This suggests that mineral-associated POC has a greater probability of export and preservation in marine basins than plant detritus, which may be oxidized to CO2 during transit.}, language = {en} } @article{VoglimacciStephanopoliWendlederLantuitetal.2022, author = {Voglimacci-Stephanopoli, Jo{\"e}lle and Wendleder, Anna and Lantuit, Hugues and Langlois, Alexandre and Stettner, Samuel and Schmitt, Andreas and Dedieu, Jean-Pierre and Roth, Achim and Royer, Alain}, title = {Potential of X-band polarimetric synthetic aperture radar co-polar phase difference for arctic snow depth estimation}, series = {Cryosphere}, volume = {16}, journal = {Cryosphere}, number = {6}, publisher = {Copernicus}, address = {G{\"o}ttingen}, issn = {1994-0416}, doi = {10.5194/tc-16-2163-2022}, pages = {2163 -- 2181}, year = {2022}, abstract = {Changes in snowpack associated with climatic warming has drastic impacts on surface energy balance in the cryosphere. Yet, traditional monitoring techniques, such as punctual measurements in the field, do not cover the full snowpack spatial and temporal variability, which hampers efforts to upscale measurements to the global scale. This variability is one of the primary constraints in model development. In terms of spatial resolution, active microwaves (synthetic aperture radar - SAR) can address the issue and outperform methods based on passive microwaves. Thus, high-spatial-resolution monitoring of snow depth (SD) would allow for better parameterization of local processes that drive the spatial variability of snow. The overall objective of this study is to evaluate the potential of the TerraSAR-X (TSX) SAR sensor and the wave co-polar phase difference (CPD) method for characterizing snow cover at high spatial resolution. Consequently, we first (1) investigate SD and depth hoar fraction (DHF) variability between different vegetation classes in the Ice Creek catchment (Qikiqtaruk/Herschel Island, Yukon, Canada) using in situ measurements collected over the course of a field campaign in 2019; (2) evaluate linkages between snow characteristics and CPD distribution over the 2019 dataset; and (3) determine CPD seasonality considering meteorological data over the 2015-2019 period. SD could be extracted using the CPD when certain conditions are met. A high incidence angle (>30 circle) with a high topographic wetness index (TWI) (>7.0) showed correlation between SD and CPD (R2 up to 0.72). Further, future work should address a threshold of sensitivity to TWI and incidence angle to map snow depth in such environments and assess the potential of using interpolation tools to fill in gaps in SD information on drier vegetation types.}, language = {en} } @article{HaugkJongejansMangelsdorfetal.2022, author = {Haugk, Charlotte and Jongejans, Loeka L. and Mangelsdorf, Kai and Fuchs, Matthias and Ogneva, Olga and Palmtag, Juri and Mollenhauer, Gesine and Mann, Paul J. and Overduin, P. Paul and Grosse, Guido and Sanders, Tina and Tuerena, Robyn E. and Schirrmeister, Lutz and Wetterich, Sebastian and Kizyakov, Alexander and Karger, Cornelia and Strauss, Jens}, title = {Organic matter characteristics of a rapidly eroding permafrost cliff in NE Siberia (Lena Delta, Laptev Sea region)}, series = {Biogeosciences}, volume = {19}, journal = {Biogeosciences}, number = {7}, publisher = {Copernicus}, address = {G{\"o}ttingen}, issn = {1726-4170}, doi = {10.5194/bg-19-2079-2022}, pages = {2079 -- 2094}, year = {2022}, abstract = {Organic carbon (OC) stored in Arctic permafrost represents one of Earth's largest and most vulnerable terrestrial carbon pools. Amplified climate warming across the Arctic results in widespread permafrost thaw. Permafrost deposits exposed at river cliffs and coasts are particularly susceptible to thawing processes. Accelerating erosion of terrestrial permafrost along shorelines leads to increased transfer of organic matter (OM) to nearshore waters. However, the amount of terrestrial permafrost carbon and nitrogen as well as the OM quality in these deposits is still poorly quantified. We define the OM quality as the intrinsic potential for further transformation, decomposition and mineralisation. Here, we characterise the sources and the quality of OM supplied to the Lena River at a rapidly eroding permafrost river shoreline cliff in the eastern part of the delta (Sobo-Sise Island). Our multi-proxy approach captures bulk elemental, molecu- lar geochemical and carbon isotopic analyses of Late Pleistocene Yedoma permafrost and Holocene cover deposits, discontinuously spanning the last similar to 52 kyr. We showed that the ancient permafrost exposed in the Sobo-Sise cliff has a high organic carbon content (mean of about 5 wt \%). The oldest sediments stem from Marine Isotope Stage (MIS) 3 interstadial deposits (dated to 52 to 28 cal ka BP) and are overlaid by last glacial MIS 2 (dated to 28 to 15 cal ka BP) and Holocene MIS 1 (dated to 7-0 cal ka BP) deposits. The relatively high average chain length (ACL) index of n-alkanes along the cliff profile indicates a predominant contribution of vascular plants to the OM composition. The elevated ratio of isoand anteiso-branched fatty acids (FAs) relative to mid- and long-chain (C >= 20) n-FAs in the interstadial MIS 3 and the interglacial MIS 1 deposits suggests stronger microbial activity and consequently higher input of bacterial biomass during these climatically warmer periods. The overall high carbon preference index (CPI) and higher plant fatty acid (HPFA) values as well as high C/N ratios point to a good quality of the preserved OM and thus to a high potential of the OM for decomposition upon thaw. A decrease in HPFA values downwards along the profile probably indicates stronger OM decomposition in the oldest (MIS 3) deposits of the cliff. The characterisation of OM from eroding permafrost leads to a better assessment of the greenhouse gas potential of the OC released into river and nearshore waters in the future.}, language = {en} } @article{JaraMunozMelnickLietal.2022, author = {Jara-Mu{\~n}oz, Julius and Melnick, Daniel and Li, Shaoyang and Socquet, Anne and Cort{\´e}s-Aranda, Joaqu{\´i}n and Brill, Dominik and Strecker, Manfred R.}, title = {The cryptic seismic potential of the Pichilemu blind fault in Chile revealed by off-fault geomorphology}, series = {Nature communications}, volume = {13}, journal = {Nature communications}, number = {1}, publisher = {Nature Research}, address = {Berlin}, issn = {2041-1723}, doi = {10.1038/s41467-022-30754-1}, pages = {13}, year = {2022}, abstract = {The first step towards assessing hazards in seismically active regions involves mapping capable faults and estimating their recurrence times. While the mapping of active faults is commonly based on distinct geologic and geomorphic features evident at the surface, mapping blind seismogenic faults is complicated by the absence of on-fault diagnostic features. Here we investigated the Pichilemu Fault in coastal Chile, unknown until it generated a Mw 7.0 earthquake in 2010. The lack of evident surface faulting suggests activity along a partly-hidden blind fault. We used off-fault deformed marine terraces to estimate a fault-slip rate of 0.52 +/- 0.04 m/ka, which, when integrated with satellite geodesy suggests a 2.12 +/- 0.2 ka recurrence time for Mw similar to 7.0 normal-faulting earthquakes. We propose that extension in the Pichilemu region is associated with stress changes during megathrust earthquakes and accommodated by sporadic slip during upper-plate earthquakes, which has implications for assessing the seismic potential of cryptic faults along convergent margins and elsewhere.}, language = {en} } @misc{CescaStichGrigolietal.2022, author = {Cesca, Simone and Stich, Daniel and Grigoli, Francesco and Vuan, Alessandro and L{\´o}pez-Comino, Jos{\´e} {\´A}ngel and Niemz, Peter and Blanch, Estefan{\´i}a and Dahm, Torsten and Ellsworth, William L.}, title = {Reply to: Multiple induced seismicity mechanisms at Castor underground gas storage illustrate the need for thorough monitoring}, series = {Nature communications}, volume = {13}, journal = {Nature communications}, number = {1}, publisher = {Nature Research}, address = {Berlin}, issn = {2041-1723}, doi = {10.1038/s41467-022-30904-5}, pages = {4}, year = {2022}, language = {en} } @article{FuchsPalmtagJuhlsetal.2022, author = {Fuchs, Matthias and Palmtag, Juri and Juhls, Bennet and Overduin, Pier Paul and Grosse, Guido and Abdelwahab, Ahmed and Bedington, Michael and Sanders, Tina and Ogneva, Olga and Fedorova, Irina and Zimov, Nikita S. and Mann, Paul J. and Strauss, Jens}, title = {High-resolution bathymetry models for the Lena Delta and Kolyma Gulf coastal zones}, series = {Earth system science data}, volume = {14}, journal = {Earth system science data}, number = {5}, publisher = {Copernicus}, address = {G{\"o}ttingen}, issn = {1866-3508}, doi = {10.5194/essd-14-2279-2022}, pages = {2279 -- 2301}, year = {2022}, abstract = {Arctic river deltas and deltaic near-shore zones represent important land-ocean transition zones influencing sediment dynamics and nutrient fluxes from permafrost-affected terrestrial ecosystems into the coastal Arctic Ocean. To accurately model fluvial carbon and freshwater export from rapidly changing river catchments as well as assess impacts of future change on the Arctic shelf and coastal ecosystems, we need to understand the sea floor characteristics and topographic variety of the coastal zones. To date, digital bathymetrical data from the poorly accessible, shallow, and large areas of the eastern Siberian Arctic shelves are sparse. We have digitized bathymetrical information for nearly 75 000 locations from large-scale (1 V 25000-1 V 500000) current and historical nautical maps of the Lena Delta and the Kolyma Gulf region in northeastern Siberia. We present the first detailed and seamless digital models of coastal zone bathymetry for both delta and gulf regions in 50 and 200m spatial resolution. We validated the resulting bathymetry layers using a combination of our own water depth measurements and a collection of available depth measurements, which showed a strong correlation (r>0.9). Our bathymetrical models will serve as an input for a high-resolution coupled hydrodynamic-ecosystem model to better quantify fluvial and coastal carbon fluxes to the Arctic Ocean, but they may be useful for a range of other studies related to Arctic delta and near-shore dynamics such as modeling of submarine permafrost, near-shore sea ice, or shelf sediment transport. The new digital high-resolution bathymetry products are available on the PANGAEA data set repository for the Lena Delta (https://doi.org/10.1594/PANGAEA.934045; Fuchs et al., 2021a) and Kolyma Gulf region (https://doi.org/10.1594/PANGAEA.934049; Fuchs et al., 2021b), respectively. Likewise, the depth validation data are available on PANGAEA as well (https://doi.org/10.1594/PANGAEA.933187; Fuchs et al., 2021c).}, language = {en} } @article{JonesGrosseFarquharsonetal.2022, author = {Jones, Benjamin M. and Grosse, Guido and Farquharson, Louise M. and Roy-L{\´e}veill{\´e}e, Pascale and Veremeeva, Alexandra and Kanevskiy, Mikhail Z. and Gaglioti, Benjamin and Breen, Amy L. and Parsekian, Andrew D. and Ulrich, Mathias and Hinkel, Kenneth M.}, title = {Lake and drained lake basin systems in lowland permafrost regions}, series = {Nature reviews earth and environment}, volume = {3}, journal = {Nature reviews earth and environment}, number = {1}, publisher = {Springer Nature}, address = {London}, issn = {2662-138X}, doi = {10.1038/s43017-021-00238-9}, pages = {85 -- 98}, year = {2022}, abstract = {The formation, growth and drainage of lakes in Arctic and boreal lowland permafrost regions influence landscape and ecosystem processes. These lake and drained lake basin (L-DLB) systems occupy >20\% of the circumpolar Northern Hemisphere permafrost region and similar to 50\% of the area below 300 m above sea level. Climate change is causing drastic impacts to L-DLB systems, with implications for permafrost dynamics, ecosystem functioning, biogeochemical processes and human livelihoods in lowland permafrost regions. In this Review, we discuss how an increase in the number of lakes as a result of permafrost thaw and an intensifying hydrologic regime are not currently offsetting the land area gained through lake drainage, enhancing the dominance of drained lake basins (DLBs).The contemporary transition from lakes to DLBs decreases hydrologic storage, leads to permafrost aggradation, increases carbon sequestration and diversifies the shifting habitat mosaic in Arctic and boreal regions. However, further warming could inhibit permafrost aggradation in DLBs, disrupting the trajectory of important microtopographic controls on carbon fluxes and ecosystem processes in permafrost-region L-DLB systems. Further research is needed to understand the future dynamics of L-DLB systems to improve Earth system models, permafrost carbon feedback assessments, permafrost hydrology linkages, infrastructure development in permafrost regions and the well-being of northern socio-ecological systems.}, language = {en} } @article{SarrDonnadieuBoltonetal.2022, author = {Sarr, Anta-Clarisse and Donnadieu, Yannick and Bolton, Clara T. and Ladant, Jean-Baptiste and Licht, Alexis and Fluteau, Fr{\´e}d{\´e}ric and Laugi{\´e}, Marie and Tardif, Delphine and Dupont-Nivet, Guillaume}, title = {Neogene South Asian monsoon rainfall and wind histories diverged due to topographic effects}, series = {Nature geoscience}, volume = {15}, journal = {Nature geoscience}, number = {4}, publisher = {Nature Research}, address = {Berlin}, issn = {1752-0894}, doi = {10.1038/s41561-022-00919-0}, pages = {314 -- 319}, year = {2022}, abstract = {The drivers of the evolution of the South Asian Monsoon remain widely debated. An intensification of monsoonal rainfall recorded in terrestrial and marine sediment archives from the earliest Miocene (23-20 million years ago (Ma)) is generally attributed to Himalayan uplift. However, Indian Ocean palaeorecords place the onset of a strong monsoon around 13 Ma, linked to strengthening of the southwesterly winds of the Somali Jet that also force Arabian Sea upwelling. Here we reconcile these divergent records using Earth system model simulations to evaluate the interactions between palaeogeography and ocean-atmosphere dynamics. We show that factors forcing the South Asian Monsoon circulation versus rainfall are decoupled and diachronous. Himalayan and Tibetan Plateau topography predominantly controlled early Miocene rainfall patterns, with limited impact on ocean-atmosphere circulation. The uplift of the East African and Middle Eastern topography played a pivotal role in the establishment of the modern Somali Jet structure above the western Indian Ocean, while strong upwelling initiated as a direct consequence of the emergence of the Arabian Peninsula and the onset of modern-like atmospheric circulation. Our results emphasize that although elevated rainfall seasonality was probably a persistent feature since the India-Asia collision in the Paleogene, modern-like monsoonal atmospheric circulation only emerged in the late Neogene.}, language = {en} }