The ST22 chronology for the Skytrain Ice Rise ice core – Part 2: An age model to the last interglacial and disturbed deep stratigraphy

We present an age model for the 651 m deep ice core from Skytrain Ice Rise, situated inland of the Ronne Ice Shelf, Antarctica. The top 2000 years have previously been dated using age markers interpolated through annual layer counting. Below this, we align the Skytrain core to the AICC2012 age model using tie points in the ice and air phase, and we apply the Paleochrono program to obtain the best fit to the tie points and glaciological constraints. In the gas phase, ties are made using methane and, in critical sections, δ18Oair; in the ice phase ties are through 10Be across the Laschamps event and through ice chemistry related to long-range dust transport and deposition. This strategy provides a good outcome to about 108 ka (∼ 605 m). Beyond that there are signs of flow disturbance, with a section of ice probably repeated. Nonetheless values of CH4 and δ18Oair confirm that part of the last interglacial (LIG), from about 117–126 ka (617–627 m), is present and in chronological order. Below this there are clear signs of stratigraphic disturbance, with rapid oscillation of values in both the ice and gas phase at the base of the LIG section, below 628 m. Based on methane values, the warmest part of the LIG and the coldest part of the penultimate glacial are missing from our record. Ice below 631 m appears to be of age > 150 ka

Millennial-scale atmospheric CO<sub>2</sub> variations during the Marine Isotope Stage 6 period (190–135 ka)

International audienceAbstract. Using new and previously published CO2 data from the EPICA Dome C ice core (EDC), we reconstruct a new high-resolution record of atmospheric CO2 during Marine Isotope Stage (MIS) 6 (190 to 135 ka) the penultimate glacial period. Similar to the last glacial cycle, where high-resolution data already exists, our record shows that during longer North Atlantic (NA) stadials, millennial CO2 variations during MIS 6 are clearly coincident with the bipolar seesaw signal in the Antarctic temperature record. However, during one short stadial in the NA, atmospheric CO2 variation is small (∼5 ppm) and the relationship between temperature variations in EDC and atmospheric CO2 is unclear. The magnitude of CO2 increase during Carbon Dioxide Maxima (CDM) is closely related to the NA stadial duration in both MIS 6 and MIS 3 (60–27 ka). This observation implies that during the last two glacials the overall bipolar seesaw coupling of climate and atmospheric CO2 operated similarly. In addition, similar to the last glacial period, CDM during the earliest MIS 6 show different lags with respect to the corresponding abrupt CH4 rises, the latter reflecting rapid warming in the Northern Hemisphere (NH). During MIS 6i at around 181.5±0.3 ka, CDM 6i lags the abrupt warming in the NH by only 240±320 years. However, during CDM 6iv (171.1±0.2 ka) and CDM 6iii (175.4±0.4 ka) the lag is much longer: 1290±540 years on average. We speculate that the size of this lag may be related to a larger expansion of carbon-rich, southern-sourced waters into the Northern Hemisphere in MIS 6, providing a larger carbon reservoir that requires more time to be depleted

Estimation of dairy goat body composition: A direct calibration and comparison of eight methods

International audienceThe objective was to compare eight methods for estimation of dairy goat body composition, by calibrating against chemical composition (water, lipid, protein, mineral and energy) measured post-mortem. The methods tested on 20 Alpine goats were body condition score (BCS), 3-dimension imaging (3D) automatic assessment of BCS or whole body scan, ultrasound, computer tomography (CT), adipose cell diameter, deuterium oxide dilution space (D 2 OS) and bioelectrical impedance spectroscopy (BIS). Regressions were tested between predictive variates derived from the methods and empty body (EB) composition. The best equations for estimation of EB lipid mass included BW combined with i) perirenal adipose tissue mass and cell diameter (R 2 = 0.95, residual standard deviation, rSD = 0.57 kg), ii) volume of fatty tissues measured by CT (R 2 = 0.92, rSD = 0.76 kg), iii) D 2 OS (R 2 = 0.91, rSD = 0.85 kg), and iv) resistance at infinite frequency from BIS (R 2 = 0.87, rSD = 1.09 kg). The D 2 OS combined with BW provided the best equation for EB protein mass (R 2 = 0.97, rSD = 0.17 kg), whereas BW alone provided a fair estimate (R 2 = 0.92, rSD = 0.25 kg). Sternal BCS combined with BW provided good estimation of EB lipid and protein mass (R 2 = 0.80 and 0.95, rSD = 1.27 and 0.22 kg, respectively). Compared to manual BCS, BCS by 3D slightly decreased the precision of the predictive equation for EB lipid (R 2 = 0.74, rSD = 1.46 kg), and did not improve the estimation of EB protein compared with BW alone. Ultrasound measurements and whole body 3D imaging methods were not satisfactory estimators of body composition (R 2 ≤ 0.40). Further developments in body composition techniques may contribute for high-throughput phenotyping of robustness

High-resolution atmospheric CO2 and CH4 records derived from the EPICA Dome C ice core and stable isotope records from marine sediment core IODP Site U1385 covering MIS 9e - 12a

High-resolution atmospheric carbon dioxide (CO2) and methane (CH4) records derived from the European Project for Ice Coring in Antarctica (EPICA) Dome C ice core covering Marine Isotope Stage (MIS) 9e - 12a (~330 - 450 ka BP). The majority of the CO2 data were measured at an average temporal resolution of ~300 years using a novel dry-extraction device called the Centrifugal Ice Microtome (CIM) employed at Climate and Environmental Physics (CEP), Physics Institute, University of Bern, Switzerland. Additional 33 data points were measured at the Institut des Géosciences de l'Environnement (IGE), Univ. Grenoble Alpes, France using the Ball Mill dry-extraction system. The CH4 data were measured at both CEP and IGE, improving the temporal resolution of existing data previously published by the same laboratories to ~350 years on average. These ice core records are complemented by high-resolution planktic and benthic stable isotope (δ18O and δ13C) records from the International Ocean Discovery Program (IODP) Site U1385 located on the Iberian Margin off the coast of Portugal (Shackleton Site) covering MIS 9e - 11c (~330 - 410 ka BP). All marine sediment data were measured at an average temporal resolution of ~150 years at the Godwin Laboratory of Palaeoclimate Research, University of Cambridge, UK

Stable isotope record of benthic foraminifera in marine sediment core IODP Site U1385 covering MIS 9e – 11c

Stable isotope record of benthic foraminifera belonging to the genus Cibicidoides from the International Ocean Discovery Program (IODP) Site U1385 located on the Iberian Margin off the coast of Portugal covering Marine Isotope Stage (MIS) 9e - 11c

In vivo estimation of body composition: comparison of eight methods in dairy goats

International audienceThe objective was to test 8 methods for estimation of empty body lipid (EBL) and protein (EBP) mass in dairy goats. The methods tested on 20 Alpine goats (3±0.6 years old; 226±9 DIM; 47 to 72 kg of BW) were: adipose cell size; deuterium oxide dilution space (D2OS); 3-dimension (3D) imaging: whole body 3D-scan and automatic 3D assessment of body condition score (3D-BCS); manual sternal and lumbar BCS and ultrasound imagery; computer tomography and bioelectrical impedance spectroscopy (BIS). Simple and multiple regressions (Proc GLM, SAS) were tested between different variables and EBL and EBP mass measured by chemical analyses after slaughter. Perirenal adipose tissue mass and cell diameter combined with BW provided the most accurate predictive equations for EBL (R2=0.95, residual coefficient of variation, rCV=12%). Nonetheless, such predictors can only be measured postmortem. The best equations for EBL derived from in vivo variables included BW combined with 1/ the volume of fatty tissues measured by computer tomography (R2=0.92, rCV=17%), 2/ the D2OS (R2=0.91, rCV=19%), and 3/ the BIS (R2=0.87, rCV=23%). D2OS combined with BW provided the best equation for EBP (R2=0.97, rCV=3%), whereas BW alone provided a fair EBP estimate (R2=0.92, rCV=4%). Manual BCS combined with BW provided good EBL and EBP estimations (R2=0.80 and 0.94, rCV=28 and 4%, respectively). BCS is a non-invasive technique and does not require particular equipment, but it is subjective and prone to operator bias. Compared to manual BCS, 3D-BCS combined with BW slightly decreased the accuracy of the predictive equation for EBL (R2=0.74, rCV=32%), and did not improve the estimation of EBP compared with BW alone. Ultrasound and whole body 3D imaging techniques were not satisfactory estimators of EBL and EBP (R2≤0.40)

Compilation of CH4 records derived from the EPICA Dome C ice core covering MIS 9e - 12a

Compilation of improved CH4 data derived from the European Project for Ice Coring in Antarctica (EPICA) Dome C ice core covering Marine Isotope Stage (MIS) 9e - 12a. For this compilation, vertically contiguous (i.e. directly neighbouring) replicate measurements of the source CH4 dataset Nehrbass-Ahles et al. (2020) (https://doi.org/10.1594/PANGAEA.914907) have been averaged and are reported as single data points

Amospheric carbon dioxide of the Marine Isotope Stage 6 period (190-135 ka) from the EPICA Dome C ice core

We measured 177 new data points of atmospheric CO2 concentrations from the EPICA Dome C (EDC) ice core (75°06'S, 123°24'E) spanning MIS 6 (190 to 135 kyr BP) at the Institut des Géosciences de l'Environnement (IGE), France and Climate and Environmental Physics (CEP), Physics Institute, University of Bern, Switzerland. The majority of all atmospheric CO2 samples (i.e. 150) were measured using the ball mill dry-extraction system which is coupled to a gas chromatograph at IGE (Schaefer et al., 2011). We measured 65 samples from 27 depth intervals using the Centrifugal Ice Microtome (CIM) (Bereiter et al., 2013) at CEP. This new CO2 data measured within the scope of this study is complemented with two published datasets (Lourantou et al., 2010; Schneider et al., 2013) and one unpublished CO2 dataset measured in 2003. We use all of the available data from the EDC ice core to compile a composite dataset of atmospheric CO2 covering MIS 6 in doi:10.1594/PANGAEA.929693

Amospheric carbon dioxide of the Marine Isotope Stage 6 period (190-135 ka) from the EPICA Dome C ice core: composite smoothed record

A smoothed composite record of atmospheric CO2 covering MIS 6 based on all available data from the EDC ice core to compile a composite dataset doi:10.1594/PANGAEA.929680

High-resolution atmospheric CO2 record derived from the EPICA Dome C ice core covering MIS 9e - 12a

High-resolution atmospheric CO2 data derived from the European Project for Ice Coring in Antarctica (EPICA) Dome C ice core covering Marine Isotope Stage (MIS) 9e - 12a