Select All    Deselect All
 |   | 
Details
   print
  Records Links
Author Dominique A. Cowart, Stefano Schiaparelli, Maria Chiara Alvaro, Matteo Cecchetto, Anne-Sophie Le Port, Didier Jollivet, Stephane Hourdez doi  openurl
  Title Origin, diversity, and biogeography of Antarctic scale worms (Polychaeta: Polynoidae): a wide-scale barcoding approach Type Journal
  Year 2022 Publication Ecology and Evolution Abbreviated Journal  
  Volume 12 Issue 7 Pages e9093  
  Keywords Antarctic biogeography benthic invertebrate DNA barcoding gene flow polynoid Southern Ocean species connectivity  
  Abstract The Antarctic marine environment hosts diversified and highly endemic benthos owing to its unique geologic and climatic history. Current warming trends have increased the urgency of understanding Antarctic species history to predict how environmental changes will impact ecosystem functioning. Antarctic benthic lineages have traditionally been examined under three hypotheses: (1) high endemism and local radiation, (2) emergence of deep-sea taxa through thermohaline circulation, and (3) species migrations across the Polar Front. In this study, we investigated which hypotheses best describe benthic invertebrate origins by examining Antarctic scale worms (Polynoidae). We amassed 691 polynoid sequences from the Southern Ocean and neighboring areas: the Kerguelen and Tierra del Fuego (South America) archipelagos, the Indian Ocean, and waters around New Zealand. We performed phylogenetic reconstructions to identify lineages across geographic regions, aided by mitochondrial markers cytochrome c oxidase subunit I (Cox1) and 16S ribosomal RNA (16S). Additionally, we produced haplotype networks at the species scale to examine genetic diversity, biogeographic separations, and past demography. The Cox1 dataset provided the most illuminating insights into the evolution of polynoids, with a total of 36 lineages identified. Eunoe sp. was present at Tierra del Fuego and Kerguelen, in favor of the latter acting as a migration crossroads. Harmothoe fuligineum, widespread around the Antarctic continent, was also present but isolated at Kerguelen, possibly resulting from historical freeze–thaw cycles. The genus Polyeunoa appears to have diversified prior to colonizing the continent, leading to the co-occurrence of at least three cryptic species around the Southern and Indian Oceans. Analyses identified that nearly all populations are presently expanding following a bottleneck event, possibly caused by habitat reduction from the last glacial episodes. Findings support multiple origins for contemporary Antarctic polynoids, and some species investigated here provide information on ancestral scenarios of (re)colonization. First, it is apparent that species collected from the Antarctic continent are endemic, as the absence of closely related species in the Kerguelen and Tierra del Fuego datasets for most lineages argues in favor of Hypothesis 1 of local origin. Next, Eunoe sp. and H. fuligineum, however, support the possibility of Kerguelen and other sub-Antarctic islands acting as a crossroads for larvae of some species, in support of Hypothesis 3. Finally, the genus Polyeunoa, conversely, is found at depths greater than 150 m and may have a deep origin, in line with Hypothesis 2. These “non endemic” groups, nevertheless, have a distribution that is either north or south of the Antarctic Polar Front, indicating that there is still a barrier to dispersal, even in the deep sea.  
  Programme 1044  
  Campaign  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 2045-7758 ISBN Medium  
  Area Expedition Conference  
  Notes Approved yes  
  Call Number Serial (down) 8581  
Permanent link to this record
 

 
Author Joanna Charton, Irene Schimmelpfennig, Vincent Jomelli, Guillaume Delpech, Pierre-Henri Blard, Régis Braucher, Deborah Verfaillie, Vincent Favier, Vincent Rinterknecht, Hugues Goosse, Xavier Crosta, Léo Chassiot, Léo Martin, Damien Guillaume, Claude Legentil doi  openurl
  Title New cosmogenic nuclide constraints on Late Glacial and Holocene glacier fluctuations in the sub-Antarctic Indian Ocean (Kerguelen Islands, 49°S) Type Journal
  Year 2022 Publication Quaternary Science Reviews Abbreviated Journal  
  Volume 283 Issue Pages 107461  
  Keywords Antarctic cold reversal Be CRE dating Cl CRE dating Glacier fluctuations Holocene Kerguelen islands Late glacial Paleoclimate Southern mid-latitudes Sub-Antarctic  
  Abstract Cosmogenic nuclide dating of glacial landforms on the Kerguelen Archipelago (49°S, 69°E) gives the opportunity to study multi-millennial glacier fluctuations within the sub-Antarctic sector of the Indian Ocean. We here dated such geomorphic features to provide time constraints over the last 17,000 years using in situ-produced 36Cl in three glacial valleys: Val Travers valley, Ampere Glacier valley and Arago Glacier valley. For the first time, a combination of in situ-produced 36Cl and 10Be dating and 26Al/10Be ratios analysis was performed in the quartz-bearing syenite boulders of the Arago Glacier site. In addition, a Bayesian approach was computed to obtain a better constraint on moraine dating. Glacial advances occurred during the Late Glacial at 16.0 ± 1.9 ka and at 12.9 ± 1.7 ka in Val Travers, and at 13.6 ± 1.8 ka in Arago Glacier valley, probably linked to the Heinrich Stadial 1 and/or Antarctic Cold Reversal events, respectively. This suggests that all glaciers at this latitude were broadly sensitive to the large-scale climatic signal of the Antarctic Cold Reversal. So far, no Early nor Mid-Holocene moraines have been found in the glacial valleys on Kerguelen, indicating that the glaciers had probably receded significantly during these periods. This is in agreement with previously determined 14C ages from peat bogs, which suggest extensive deglaciation during several millennia of the Holocene period. Samples from glacially-polished bedrock surfaces (ranging from ∼4.4 ka to ∼14 ka) at Ampere Glacier site also suggest that this valley was ice free for several millennia during the Holocene. Finally, glaciers seem to have re-advanced only during the Late Holocene, especially within the last millennium, at ∼1 ka, ∼ 430 yr and ∼300 yr. A comparison of this new dataset with the available 10Be ages from other southern mid-latitude regions during the Holocene allows the identification of three different glacier evolution patterns. We suspect that variations of Kerguelen glaciers, which are located in the Southern Indian Ocean, were controlled by the combined effects of sea surface temperature related to the variations of the Antarctic Polar Front and fluctuations of precipitation related to long-term variations of the Southern Annular Mode.  
  Programme 1077  
  Campaign  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0277-3791 ISBN Medium  
  Area Expedition Conference  
  Notes Approved yes  
  Call Number Serial (down) 8580  
Permanent link to this record
 

 
Author Lvaro L. Pea Cantero doi  openurl
  Title On a few benthic hydroids (Cnidaria, Hydrozoa) from the Kerguelen Islands (southern Indian Ocean), including the description of a new species Type Journal
  Year 2022 Publication Zootaxa Abbreviated Journal  
  Volume 5165 Issue 2 Pages 274-286  
  Keywords Animal Distribution Animals Hydrozoa Indian Ocean Islands  
  Abstract A few samples of benthic hydroids from the remote Kerguelen Islands have been studied. The material was collected within the French research program ProteKer in 2013 and 2014. Six species were found in the material, four anthoathecates and two leptothecates; two of the species were identified only to genus level. All species, including Candelabrum bitentaculatum sp. nov., are described and discussed.  
  Programme 1044  
  Campaign  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1175-5334 ISBN Medium  
  Area Expedition Conference  
  Notes Approved yes  
  Call Number Serial (down) 8579  
Permanent link to this record
 

 
Author Roman Sulzbach, Hartmut Wziontek, Michael Hart-Davis, Henryk Dobslaw, Hans-Georg Scherneck, Michel Van Camp, Ove Christian Dahl Omang, Ezequiel D. Antokoletz, Christian Voigt, Denise Dettmering, Maik Thomas doi  openurl
  Title Modeling gravimetric signatures of third-degree ocean tides and their detection in superconducting gravimeter records Type Journal
  Year 2022 Publication Journal of Geodesy Abbreviated Journal  
  Volume 96 Issue 5 Pages 35  
  Keywords Degree-3 tides Superconducting gravimetry Tidal analysis Tidal modeling Tide gauge data  
  Abstract We employ the barotropic, data-unconstrained ocean tide model TiME to derive an atlas for degree-3 tidal constituents including monthly to terdiurnal tidal species. The model is optimized with respect to the tide gauge data set TICON-td that is extended to include the respective tidal constituents of diurnal and higher frequencies. The tide gauge validation shows a root-mean-square (RMS) deviation of 0.9–1.3 mm for the individual species. We further model the load tide-induced gravimetric signals by two means (1) a global load Love number approach and (2) evaluating Greens-integrals at 16 selected locations of superconducting gravimeters. The RMS deviation between the amplitudes derived using both methods is below $$0.5 \ $$nGal ($$1 \ $$nGal $$= 0.01 \frac{\text {nm}}{\text {s}^2}$$) when excluding near-coastal gravimeters. Utilizing ETERNA-x, a recently upgraded and reworked tidal analysis software, we additionally derive degree-3 gravimetric tidal constituents for these stations, based on a hypothesis-free wave grouping approach. We demonstrate that this analysis is feasible, yielding amplitude predictions of only a few 10 nGal, and that it agrees with the modeled constituents on a level of 63–80% of the mean signal amplitude. Larger deviations are only found for lowest amplitude signals, near-coastal stations, or shorter and noisier data sets.  
  Programme 688  
  Campaign  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1432-1394 ISBN Medium  
  Area Expedition Conference  
  Notes Approved yes  
  Call Number Serial (down) 8578  
Permanent link to this record
 

 
Author Gauthier Vérin, Florent Domine, Marcel Babin, Ghislain Picard, Laurent Arnaud doi  openurl
  Title Metamorphism of snow on Arctic sea ice during the melt season: impact on spectral albedo and radiative fluxes through snow Type Journal
  Year 2022 Publication The Cryosphere Abbreviated Journal  
  Volume 16 Issue 9 Pages 3431-3449  
  Keywords  
  Abstract The energy budget of Arctic sea ice is strongly affected by the snow cover. Intensive sampling of snow properties was conducted near Qikiqtarjuaq in Baffin Bay on typical landfast sea ice during two melt seasons in 2015 and 2016. The sampling included stratigraphy, vertical profiles of snow specific surface area (SSA), density and irradiance, and spectral albedo (300–1100 nm). Both years featured four main phases: (I) dry snow cover, (II) surface melting, (III) ripe snowpack, and (IV) melt pond formation. Each phase was characterized by distinctive physical and optical properties. A high SSA value of 49.3 m2 kg−1 was measured during phase I on surface wind slabs together with a corresponding broadband albedo (300–3000 nm) of 0.87. Phase II was marked by alternating episodes of surface melting, which dramatically decreased the SSA below 3 m2 kg−1, and episodes of snowfall re-establishing pre-melt conditions. Albedo was highly time-variable, with minimum broadband values around 0.70. In phase III, continued melting led to a fully ripe snowpack composed of clustered rounded grains. Albedo began to decrease in the visible as snow thickness decreased but remained steady at longer wavelengths. Moreover, significant spatial variability appeared for the first time following snow depth heterogeneity. Spectral albedo was simulated by radiative transfer using measured SSA and density vertical profiles and estimated impurity contents based on limited measurements. Simulations were most of the time within 1 % of measurements in the visible and within 2 % in the infrared. Simulations allowed the calculations of albedo and of the spectral flux at the snow–ice interface. These showed that photosynthetically active radiation fluxes at the bottom of the snowpack durably exceeded 5 W m−2 (∼9.2 µmol m−2 s−1) only when the snowpack thickness started to decrease at the end of phase II.  
  Programme 1042  
  Campaign  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1994-0416 ISBN Medium  
  Area Expedition Conference  
  Notes Approved yes  
  Call Number Serial (down) 8577  
Permanent link to this record
 

 
Author David Costantini, Pierre Blévin, Jan Ove Bustnes, Valérie Esteve, Geir Wing Gabrielsen, Dorte Herzke, Ségolène Humann-Guilleminot, Børge Moe, Charline Parenteau, Charlotte Récapet, Paco Bustamante, Olivier Chastel doi  isbn
openurl 
  Title Integument carotenoid-based colouration reflects contamination to perfluoroalkyl substances, but not mercury, in arctic black-legged kittiwakes Type Journal
  Year 2022 Publication Frontiers in ecology and evolution Abbreviated Journal  
  Volume 10 Issue 952765 Pages  
  Keywords  
  Abstract Anthropogenic activities are introducing multiple chemical contaminants into ecosystems that act as stressors for wildlife. Perfluoroalkyl substances (PFAS) and mercury (Hg) are two relevant contaminants that may cause detrimental effects on the fitness of many aquatic organisms. However, there is a lack of information on their impact on the expression of secondary sexual signals that animals use for mate choice. We have explored the correlations between integument carotenoid-based colourations, blood levels of carotenoids, and blood levels of seven PFAS and of total Hg (THg) in 50 adult male black-legged kittiwakes (Rissa tridactyla) from the Norwegian Arctic during the pre-laying period, while controlling for other colouration influencing variables such as testosterone and body condition. Kittiwakes with elevated blood concentrations of PFAS (PFOSlin, PFNA, PFDcA, PFUnA, or PFDoA) had less chromatic but brighter bills, and brighter gape and tongue; PFOSlin was the pollutant with the strongest association with bill colourations. Conversely, plasma testosterone was the only significant correlate of hue and chroma of both gape and tongue, and of hue of the bill. Kittiwakes with higher concentrations of any PFAS, but not of THg, tended to have significantly higher plasma concentrations of the carotenoids astaxanthin, zeaxanthin, lutein, and cryptoxanthin. Our work provides the first correlative evidence that PFAS exposure might interfere with the carotenoid metabolism and the expression of integument carotenoid-based colourations in a free-living bird species. This outcome may be a direct effect of PFAS exposure or be indirectly caused by components of diet that also correlate with elevated PFAS concentrations (e.g., proteins). It also suggests that there might be no additive effect of THg co-exposure with PFAS on the expression of colourations. These results call for further work on the possible interference of PFAS with the expression of colourations used in mate choice.  
  Programme 330  
  Campaign  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 2296-701X ISBN 2296-701X Medium  
  Area Expedition Conference  
  Notes Approved yes  
  Call Number Serial (down) 8576  
Permanent link to this record
 

 
Author Eleonora Fossile, Maria Pia Nardelli, Hélène Howa, Agnès Baltzer, Yohann Poprawski, Ilaria Baneschi, Marco Doveri, Meryem Mojtahid doi  openurl
  Title Influence of modern environmental gradients on foraminiferal faunas in the inner Kongsfjorden (Svalbard) Type Journal
  Year 2022 Publication Marine Micropaleontology Abbreviated Journal  
  Volume 173 Issue Pages 102117  
  Keywords Arctic Benthic foraminifera Bioindicators Fjord hydrology Tidewater glacier  
  Abstract Kongsfjorden (Svalbard archipelago) is subjected to strong environmental gradients creating high physical and geochemical stress on benthic faunas. The present study aims at understanding the environmental drivers governing benthic foraminifera in the innermost part of the fjord. Surface sediments from 9 stations were sampled during August 2018 along a transect starting at ca. 2 km from the tidewater glacier Kronebreen and ending 12 km seaward. Three biozones were identified in response to disturbances linked to the proximity of the Kronebreen front (i.e., high water turbidity, freshwater, and sediment inputs, reduced organic fluxes). Close to the terminus (proximal biozone), few stress-tolerant and glacier proximal species were present (i.e., Capsammina bowmanni and Cassidulina reniforme). At about 6–8 km from the front (medial biozone), reduced turbidity, and increased organic fluxes, resulted in a higher diversity, and a high abundance of the phytodetritus-indicator Nonionellina labradorica. Relatively high diversity persisted until 12 km from the front due to higher organic inputs and reduced stressful conditions. The distal biozone was dominated by the Atlantic Water (AW) indicator Adercotryma glomeratum, in coherence with the presence of warm and salty AW detected far inside the fjord. Physical stress related to the glacier dynamics appears to favour the establishment of opportunistic species close to the terminus, whereas reduced disturbance away from the glacier induces the establishment of diverse assemblages. Our results show that benthic foraminifera may be effective bioindicators to monitor the long-term retreat of tidewater glaciers induced by climate change in Kongsfjorden.  
  Programme 1223  
  Campaign  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0377-8398 ISBN Medium  
  Area Expedition Conference  
  Notes Approved yes  
  Call Number Serial (down) 8575  
Permanent link to this record
 

 
Author Félicie Korostelev, Yang Lu, Fabrizio Magrini, Lapo Boschi, Sylvie Leroy, William Vétel doi  openurl
  Title Images of the East African Rift System by Global Adaptive-Resolution Surface-Wave Tomography Type Journal
  Year 2022 Publication Journal of Geophysical Research: Solid Earth Abbreviated Journal  
  Volume 127 Issue 6 Pages e2021JB023570  
  Keywords East African Rift System surface-wave velocity model  
  Abstract In this study we map the entire East African Rift System (EARS) within a global surface-wave velocity model to better constrain the structure of the underlying mantle, as well as patterns that might be associated with its continuation in the Mozambique Channel. We use all publicly available seismograms from the African continent, amounting to 1296 stations and more than 30 years of recordings. From these data, we obtain dispersion curves using both ambient noise and teleseismic earthquakes. To our measurements, we add global counterparts and jointly invert them for phase-velocity maps. We exploit a linearized inversion based on the ray theory, with an adaptive parameterization that allows for maximizing the resolution of the final maps based on the density of data coverage. We thus image the main African cratons and also some of the Archean blocks within them. We highlight the discontinuous nature of magmatic activity along the EARS and also display low-velocity anomalies beneath the Comores Archipelago, Madagascar and Bassas da India volcanic islands and seamounts. This last low-velocity anomaly is in the direct continuation of the EARS and could unveil an important magmatic system in the Mozambique Channel.  
  Programme 133  
  Campaign  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 2169-9356 ISBN Medium  
  Area Expedition Conference  
  Notes Approved yes  
  Call Number Serial (down) 8574  
Permanent link to this record
 

 
Author Lucas Sawade, Stephen Beller, Wenjie Lei, Jeroen Tromp doi  openurl
  Title Global centroid moment tensor solutions in a heterogeneous earth: the CMT3D catalogue Type Journal
  Year 2022 Publication Geophysical Journal International Abbreviated Journal  
  Volume 231 Issue 3 Pages 1727-1738  
  Keywords  
  Abstract For over 40 yr, the global centroid-moment tensor (GCMT) project has determined location and source parameters for globally recorded earthquakes larger than magnitude 5.0. The GCMT database remains a trusted staple for the geophysical community. Its point-source moment-tensor solutions are the result of inversions that model long-period observed seismic waveforms via normal-mode summation for a 1-D reference earth model, augmented by path corrections to capture 3-D variations in surface wave phase speeds, and to account for crustal structure. While this methodology remains essentially unchanged for the ongoing GCMT catalogue, source inversions based on waveform modelling in low-resolution 3-D earth models have revealed small but persistent biases in the standard modelling approach. Keeping pace with the increased capacity and demands of global tomography requires a revised catalogue of centroid-moment tensors (CMT), automatically and reproducibly computed using Green's functions from a state-of-the-art 3-D earth model. In this paper, we modify the current procedure for the full-waveform inversion of seismic traces for the six moment-tensor parameters, centroid latitude, longitude, depth and centroid time of global earthquakes. We take the GCMT solutions as a point of departure but update them to account for the effects of a heterogeneous earth, using the global 3-D wave speed model GLAD-M25. We generate synthetic seismograms from Green's functions computed by the spectral-element method in the 3-D model, select observed seismic data and remove their instrument response, process synthetic and observed data, select segments of observed and synthetic data based on similarity, and invert for new model parameters of the earthquake’s centroid location, time and moment tensor. The events in our new, preliminary database containing 9382 global event solutions, called CMT3D for ‘3-D centroid-moment tensors’, are on average 4 km shallower, about 1 s earlier, about 5 per cent larger in scalar moment, and more double-couple in nature than in the GCMT catalogue. We discuss in detail the geographical and statistical distributions of the updated solutions, and place them in the context of earlier work. We plan to disseminate our CMT3D solutions via the online ShakeMovie platform.  
  Programme 133  
  Campaign  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0956-540X ISBN Medium  
  Area Expedition Conference  
  Notes Approved yes  
  Call Number Serial (down) 8573  
Permanent link to this record
 

 
Author Kristin N. Barton, Nairita Pal, Steven R. Brus, Mark R. Petersen, Brian K. Arbic, Darren Engwirda, Andrew F. Roberts, Joannes J. Westerink, Damrongsak Wirasaet, Michael Schindelegger doi  openurl
  Title Global Barotropic Tide Modeling Using Inline Self-Attraction and Loading in MPAS-Ocean Type Journal
  Year 2022 Publication Journal of Advances in Modeling Earth Systems Abbreviated Journal  
  Volume 14 Issue 11 Pages e2022MS003207  
  Keywords barotropic tides E3SM MPAS-Ocean numerical ocean modeling self-attraction and loading surface tides  
  Abstract We examine ocean tides in the barotropic version of the Model for Prediction Across Scales (MPAS-Ocean), the ocean component of the Department of Energy Earth system model. We focus on four factors that affect tidal accuracy: self-attraction and loading (SAL), model resolution, details of the underlying bathymetry, and parameterized topographic wave drag. The SAL term accounts for the tidal loading of Earth's crust and the self-gravitation of the ocean and the load-deformed Earth. A common method for calculating SAL is to decompose mass anomalies into their spherical harmonic constituents. Here, we compare a scalar SAL approximation versus an inline SAL using a fast spherical harmonic transform package. Wave drag accounts for energy lost by breaking internal tides that are produced by barotropic tidal flow over topographic features. We compare a series of successively finer quasi-uniform resolution meshes (62.9, 31.5, 15.7, and 7.87 km) to a variable resolution (45 to 5 km) configuration. We ran MPAS-Ocean in a single-layer barotropic mode forced by five tidal constituents. The 45 to 5 km variable resolution mesh obtained the best total root-mean-square error (5.4 cm) for the deep ocean (1,000 m) tide compared to TPXO8 and ran twice as fast as the quasi-uniform 8 km mesh, which had an error of 5.8 cm. This error is comparable to those found in other forward (non-assimilative) ocean tide models. In future work, we plan to use MPAS-Ocean to study tidal interactions with other Earth system components, and the tidal response to climate change.  
  Programme 688  
  Campaign  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1942-2466 ISBN Medium  
  Area Expedition Conference  
  Notes Approved yes  
  Call Number Serial (down) 8572  
Permanent link to this record
Select All    Deselect All
 |   | 
Details
   print