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Free neutral monosaccharides and combined monosaccharides in seawater and related saline matrices

Bulk seawater, surface microlayer, ice core and brine samples from the Arctic, the North and Tropical Atlantic and Raunefjorden were investigated on their sugar concentrations. Free neutral monosaccharides (DFCHO) and combined monosaccharides/polysaccharides (CCHO) were determined using high performance anionic exchange chromatography with pulsed amperometric detection (HPAEC-PAD) and electro-dialysis for prior desalination.

Annual mean concentrations of (non-sea-salt) sulfur, non-sea salt chlorine, fluoride, insoluble particle concentrations from an array of 19 ice cores from Antarctica and seven ice cores from Greenland

We report annual mean (non-sea salt) sulfur concentrations from 19 ice cores in Antarctica including WD, WDC05Q, B40, NUS08-4, NUS08-5, NUS08-7, NUS07-2, NUS07-5 and NUS07-7 (all analyzed using inductively coupled plasma mass spectrometry, ICPMS) and SP01, SP04, SPC14, DML05, DML07, DF01, DFS10, EDC96, Taylor Dome and Talos Dome (all analyzed using ion chromatography, IC). The latter are based on measurements of sulfate divided by three to derive the equivalent sulfur concentration. Additional details about the ice-core sites and analytical procedures are provided in the Supporting Data of Gabriel et al., (submitted) and in the references below citing the original publications. We report annual mean (non-sea salt) sulfur concentrations from 7 ice cores in Greenland: NEEM(2011-S1), Humboldt, B19, TUNU2013, Summit2010-composite (all by ICPMS) and EGRIP and NGRIP1 (by IC) . We further report insoluble size-resolved particle concentrations for the TUNU2013, B19 and NEEM(-2011)S1 ice cores, and insoluble size-resolved particle concentrations and non-sea-salt chlorine records from the Summit2015 ice core. These records are used alongside ice-core crypto-tephra to characterize volcanic eruption sources and to quantify volcanic sulfur injections from volcanic eruptions between 1590 and 1710 CE.

Bulk and position-specific isotopic composition of N2O (total and in situ) and nitrate from the EDC, EDML, Vostok, TALDICE, Taylor Glacier, and NGRIP ice cores

The mixing ratio and bulk isotopic composition of nitrous oxide (N2O) was measured after wet extraction and purification of the air enclosed in 150 g ice core samples from EDC, EDML, Vostok, TALDICE, and NGRIP, following the analysis procedure described in Schmitt et al. (2014). The position-specific isotopic composition of N2O was measured after dry extraction and purification of the air enclosed in 600 g ice core samples from Vostok and Taylor Glacier, following the analysis procedure described in Menking et al. (2025). The mixing ratio and isotopic composition of in situ N2O – i.e., the fraction of N2O produced in the ice – was calculated using a mass balance approach (Soussaintjean et al., preprint). After gas extraction, the sample meltwater and ice chips were collected to measure the isotopic composition of nitrate (NO3-) following the bacterial denitrification method described in Erbland et al. (2013). Each sample was associated with its ice age and gas age based on the AICC2023 chronology (Bouchet et al., 2023) for EDC, EDML, Vostok, TALDICE, and NGRIP and Baggenstos et al. (2017, 2018) for Talyor Glacier. The samples cover the periods 11 – 26 ka, 41 – 75 ka, and 136 – 143 ka. Taylor Glacier is a horizontal core, meaning the age of the ice varies with distance along a transect close to the surface where the horizontal stratigraphy is preserved (Baggenstos et al., 2017).

Last Glacial Maximum (LGM) paleo-dust record

Paleo±Dust: Quantifying uncertainty in paleo-dust deposition across archive types

Paleo±Dust is an updated compilation of bulk and <10-µm paleo-dust deposition rate with quantitative 1-σ uncertainties that are inter-comparable among archive types (lake sediment cores, marine sediment cores, polar ice cores, peat bog cores, loess samples). Paleo±Dust incorporates a total of 285 pre-industrial Holocene (pi-HOL) and 209 Last Glacial Maximum (LGM) dust flux constraints from studies published until December 2022. We also recalculate previously published dust fluxes to exclude data from the last deglaciation and thus obtain more representative constraints for the last pre-industrial interglacial and glacial end-member climate states. Metadata include all components necessary to derive dust deposition rate, including: age range, thickness, density, eolian content. We also include 1-sigma uncertainties on each of these components, and on the final bulk and <10-µm dust deposition rates. Specific notes for each site and a list of references are also included.

Ice core nitrous oxide over the past 2000 years

The continuous growth of atmospheric nitrous oxide (N2O) is of concern for its potential role in global warming and future stratospheric ozone destruction. Climate feedbacks that enhance N2O emissions in response to global warming are not well understood, and past records of N2O from ice cores are not sufficiently well resolved to examine the underlying climate-N2O feedbacks on societally relevant time scales. Here, we present a new high-resolution and high-precision N2O reconstruction obtained from the Greenland NEEM (North Greenland Eemian Ice Drilling) and the Antarctic Styx Glacier ice cores. Covering the N2O history of the past two millennia, our reconstruction shows a centennial-scale variability of ~10 ppb. A pronounced minimum at ~600 CE coincides with the reorganizations of tropical hydroclimate and ocean productivity changes. Comparisons with proxy records suggest association of centennial- to millennial-scale variations in N2O with changes in tropical and subtropical land hydrology and marine productivity.

The Antarctic ice core chronology (AICC2023)

We present the new reference chronology (AICC2023) providing an age vs depth relationship covering the last 800 kyr (thousands of years) for five ice cores (EDC, EDML, NGRIP, TALDICE and Vostok). To construct the new AICC2023 chronology, we used new highly resolved measurements for EDC ice core as well as novel absolute 81Kr ages, stratigraphic links between the five ice cores and accurate firn modeling estimates. The new chronological and glaciological information were combined in the Bayesian dating tool Paleochrono to obtain the AICC2023 timescale.

Holocene total nitrous oxide flux based on the composite nitrous oxide concentration data

The N2O emissions were estimated by calculating the change in total N2O flux. The total N2O global flux (TgN/yr) was calculated by clubbing the new SPICE core N2O data (Azharuddin et al, 2023) with the existing data from EPICA Dome C (EDC), Dronning Maud Land (EDML) (Flückiger et al., 2002; Schilt et al., 2010), Talos Dome Ice (TALDICE), North Greenland Ice Core Project (NGRIP) (Fischer et al., 2019), Law Dome (Rubino et al., 2019) and Styx and NEEM (Ryu et al., 2020) ice cores using a two-box model. The model assumed the stratosphere and troposphere as individual boxes where the stratospheric N2O destruction and troposphere-stratosphere N2O exchange were well constrained.

Biomass Burning Recorded in Central and North American Lake Sediments and its Impact on Climate

Humans impact fire regimes by changing fire ignition, fuels, and land cover. Although fire regimes dramatically alter interactions between the land surface, biosphere, and atmosphere, the impact of these fires on the climate system is not clear. Biomass burning caused by current human activities emits carbon dioxide equal to 50Prozent of the emissions from fossil-fuel combustion and is therefore highly likely to influence future climate change. The multi-proxy nature of ice and lake cores presents ideal material to investigate the links between biomass burning and climate change. The primary objective of the project is to study temporal and regional evolution of biomass burning during the Holocene in Central and North America to determine anthropogenic fire impacts on the climate system with the advent of agriculture and in a warming climate. This requires high-resolution biomass burning proxy records combined with Holocene climate records at the respective locations. The approach is based on analyses of levoglucosan, an excellent proxy for past biomass burning, on Central and North American lake sediment cores as well as on the Greenland NEEM deep ice core and their interpretation in context with climate records. The Department of Environmental Sciences, Informatics, and Statistics of the University of Venice is particularly suited to host this project as it is one of the worldwide leading groups in quantitative investigations of the early impact of humans on the climate system by analyzing past fires recorded in ice and sediment cores.

DML-Niederschlag und Interpretation von EPICA-Eisbohrkernen

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