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We present high-resolution measurements of CO mixing ratios from ice cores drilled at five different sites on the Greenland ice sheet. An optical-feedback cavity-enhanced absorption spectrometer (OF-CEAS) was coupled with continuous melter systems and operated during four analytical campaigns conducted between 2013 and 2019 at the Desert Research Institute (DRI, USA) and the Institut des Géoscience de l'Environnement (IGE, France). The CFA-based CO measurements exhibit excellent external precision (ranging from 3.3 to 6.6 ppbv, 1 sigma) and achieve consistently low blanks (ranging from 4.1 +/- 1.2 to 12.6 +/- 4.4 ppbv), enabling paleoatmospheric interpretations. Consistent baseline CO records from four Greenlandic sites (PLACE, D4, NGRIP, and NEEM) are combined to produce a multisite average ice core reconstruction of past atmospheric CO for the Northern Hemisphere high latitudes, covering the period from 1700 to 1957 CE. Such a reconstruction should be taken as an upper bound of past atmospheric CO abundance.

A bulk composite carbonate stable isotope, X-ray fluorescence (XRF) scanning (elemental barium), biogenic barium and benthic foraminiferal record in deep sea sediments from the tropical Pacific was produced from 71.5 to 66 million years ago to determine variations in carbon export in the Pacific during the Maastrichtian. The cores were drilled on Shatsky Rise in the tropical Pacific at Ocean Drilling Program (ODP) Leg 198 Sites 1209 and 1210 whose current locations are 32°39.1081′N, 158°30.3564′E (2387 m below sea level) and 32°13.420′N, 158°15.5623′E (2573 m below sea level), respectively (Bralower et al., 2002). Bulk carbonate δ18O and δ13C were measured in 1394 samples from both Sites 1209 (1096) and 1210 (298) about every 5 cm at MARUM, University Bremen. Bulk carbonate analyses were carried out on a Finnigan MAT 251 mass spectrometer equipped with automated carbonate preparation line (Kiel III) and reported relative to the Vienna Pee Dee Belemnite (VPDB) international standard, determined via adjustment to calibrated in-house standards and NBS-19. Non-destructive XRF data were collected every 2 cm down-core using XRF core scanner Avaatech serial no. 17 from the XRF core scanning facility at the IODP Gulf Coast Repository at Texas A&M University (College Station, USA). Data were collected over a 1.2 cm² area with a down-core slit size of 10 mm using generator settings of 50 kV and a current of 0.75 mA, ideally for detecting Ba, and a sampling time of 12 s in each run directly at the split core surface of the archive half. Discrete samples from 5 intervals that consist of 51 samples in total were processed to determine the marine barite content using a barite separation process modified from Paytan et al. (1996) and excess-Ba (bio-Ba) by measuring the digested bulk sample on a Perkin Elmer 3000DV ICP-OES and using equation from Dymond et al. (1992). Additional samples for benthic foraminifera were taken from over 2 of the 5 intervals that have barite data. Benthic foraminiferal quantitative analysis was carried out at University of Zaragoza based on representative splits of approximately 300 specimens larger than 63 µm.

We measured the concentration of in situ Be-10 and Al-26 in quartz separated from medium (250-850 micron) detrital river sand collected from 22 watersheds in central Cuba. Samples were collected in summer 2018 from watersheds ranging in size from 2 to 730 km². Be and Al extraction was completed at the University of Vermont Community Cosmogenic Facility and accelerator mass spectrometer measurements were made at PRIME Lab. Many of the sampled basins are low slope (average < 1 degree) and underlain by marine rocks. Samples are from the same locations as published chemical weathering rates inferred from dissolved loads in river water (Bierman et al. 2020).

The data collection consists of 3 datasets: - Zooplankton standing stocks: this dataset compiles the standing stocks (ind/m³), the integrated standing stocks (ind/m²) and the integrated CaCO3 standing stocks (mg/m²) for three groups of zooplanktonic calcifying organisms, pteropods, heteropods and foraminifers. The organisms were collected by oblique towing (Ø 0.5 m, 90 μm mesh size, SeaGear mechanical flowmeter) in the North Pacific between Hawaii and the Gulf of Alaska during the R/V Kilo Moana cruise KM1712 in August 2017. The sampling strategy was designed to capture an integrated sample of all foraminifers, pteropods and heteropods from juveniles to adults living throughout the upper water column. - Phytoplankton standing stocks: this dataset compiles the CaCO3 standing stocks of living coccolithophores (mg/m³), of detached coccoliths (mg/m³) and the integrated CaCO3 standing stocks of coccolithophores (mg/m²). The samples were collected in the North Pacific between Hawaii and the Gulf of Alaska during the R/V Kilo Moana cruise KM1712 in August 2017, with rosette Niskin bottles equiped with CTD (Sea-Bird SBE 9) at different depths throughout the photic zone including the deep chlorophyll maximum. - Integrated CaCO3 production: this dataset compiles the estimates of annual CaCO3 production, including the upper and lower limits of the estimates, for the 4 planktic calcifying groups considered in the study, the pteropods (mg/m²/yr), the heteropods (mg/m²/yr), the foraminifers (mg/m²/yr) and the coccolithophores (mg/m²/yr). The estimates derived from the living standing stocks of these 4 groups of organisms collected in the North Pacific between Hawaii and the Gulf of Alaska during the R/V Kilo Moana cruise KM1712 in August 2017.

We present a 60,000-yr long temperature reconstruction based on branched glycerol dialkyl glycerol tetraethers (brGDGT) in a sediment core from Lake Towuti, located in Sulawesi, Indonesia. brGDGTs were measured in one sample very 500 years. In 2020, we analyzed the samples using atmospheric pressure chemical ionization/high-performance liquid chromatography mass spectrometry (APCI/HPLC-MS) with a bridged ethylsiloxane/silica hybrid (BEH) hydrophilic interaction chromatography (HILIC) 1.7 um (2.1 x 150 mm) column using selective ion monitoring mode, targeting molecules at m/z 1050, 1048, 1046, 1036, 1034, 1032, 1022, 1020, 1018, 1292, 1296, 1298, 1300, and 1302 (Hopmans et al., 2016). The timing of the deglacial warming in our record occurs after the onset of the deglacial increase in atmospheric CO2 concentrations, which suggests rising greenhouse gas concentrations and the associated radiative forcing may have forced deglacial warming in the IPWP. Peaks in temperature around 55 ka and 34 ka indicate that Northern Hemisphere summer insolation may also influence land surface temperature in the IPWP region.

Sediment coreP1-93AR-P23 was collected in 1993 from the Northwind Ridge, western Arctic Ocean. Sediments were leached in 2011 to remove authigenic fractions. The residual leached sediments were digested using a microwave system. Strontium and neodymium were isolated using column chemistry, and analyzed by multicollector ICP-MS. The data span the time period from the late Pliocene to the most recent glacial interval, including the mid-Pleistocene transition where glacial cycles shifted from a dominant ~41ka cyclicity to a ~100ka cyclicity.

Atmospheric transport and deposition of aerosols is an important delivery mechanism of natural and contaminant trace elements (TEs) to the Arctic, but direct measurements of TE fluxes are difficult and unreliable. The naturally occurring isotope Beryllium-7 (Be-7) can be used as a tracer of aerosol deposition and to provide reliable seasonal TE flux estimates. Be-7 is a cosmic ray produced isotope (half life 53.3 days) that is deposited upon the ocean surface primarily by precipitation. The standing crop (inventory) of Be-7 in the surface ocean (including snow and ice) affords a way to determine the deposition flux of this isotope. At steady state, the input flux of Be-7 is balanced by the decay rate of the Be-7 inventory integrated over the water column, sea ice and snow. The ability to readily derive Be-7 fluxes from ocean/ice/snow inventories provides a means to link the chemical concentrations of trace elements in aerosols to their respective atmospheric deposition fluxes through the following relationship: Flux(TEs) = Flux(Be-7) * [TEs] / [Be-7]. where [TEs] and [Be-7] are the aerosol concentrations of trace elements and Be-7, respectively. In these datasets, we present concentrations of Be-7 in surface ocean water, ice cores, snow, frost flower, and aerosol samples collected during the MOSAiC expedition in the Central Arctic Ocean from October 2019 to May 2020.

We present sea ice temperature and salinity data from first-year ice (FYI) and second-year ice (SYI) relevant to the temporal development of sea ice permeability and brine drainage efficiency from the early growth phase in October 2019 to the onset of spring warming in May 2020. Our dataset was collected in the central Arctic Ocean during the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) Expedition in 2019 to 2020. MOSAiC was an international transpolar drift expedition in which the German icebreaker RV Polarstern anchored into an ice floe to gain new insights into Arctic climate over a full annual cycle. In October 2019, RV Polarstern moored to an ice floe in the Siberian sector of the Arctic at 85 degrees north and 137 degrees east to begin the drift towards the North Pole and the Fram Strait via the Transpolar Drift Stream. The data presented here were collected during the first three legs of the expedition, so all the coring activities took place on the same floe. The end dates of legs 1, 2, and 3 were 13 December, 24 February, and 4 June, respectively. The dataset contributed to a baseline study entitled, Deciphering the properties of different Arctic ice types during the growth phase of the MOSAiC floes: Implications for future studies. The study highlights downward directed gas pathways in FYI and SYI by inferring sea ice permeability and potential brine release from several time series of temperature and salinity measurements. The physical properties presented in this paper lay the foundation for subsequent analyses on actual gas contents measured in the ice cores, as well as air-ice and ice-ocean gas fluxes. Sea ice cores were collected with a Kovacs Mark II 9 cm diameter corer. To measure ice temperatures, about 4.5 cm deep holes were drilled into the core (intervals varied by site and leg) . The temperatures were measured by a digital thermometer within minutes after the cores were retrieved. The ice cores were placed into pre-labelled plastic sleeves sealed at the bottom end. The ice cores were transported to RV Polarstern and stored in a -20 degrees Celsius freezer. Each of the cores was sub-sampled, melted at room temperature, and processed for salinity within one or two days. The practical salinity was estimated by measuring the electrical conductivity and temperature of the melted samples using a WTW Cond 3151 salinometer equipped with a Tetra-Con 325 four-electrode conductivity cell. The practical salinity represents the the salinity estimated from the electrical conductivity of the solution. The dataset also contains derived variables, including sea ice density, brine volume fraction, and the Rayleigh number.

Sediment cores at sites J1002 and J1007 were collected from the Chilean Margin during D/V JOIDES Resolution Expedition 379T (JR100) in 2019. Sedimentary Green/Blue (G/B) ratio and sedimentary U/Th derived from natural gamma radiation data were collected during the expedition. We generated age models for sites J1002 and J1007 with radiocarbon dates and visual correlation of δ18O records of benthic foraminifera to the LR04 benthic stack. Measured biogenic opal contents and organic carbon contents were compared to the G/B to test the utility of G/B as a proxy for diatom productivity at Sites J1002 and J1007. Sedimentary U/Th was further used as a non-quantitative indicator of redox conditions of the sediments. Lastly, we calculated the opal mass accumulation rate (MAR) at Site J1007 over the last ~150,000 years. Laboratory measurements in this study were conducted in 2020 at Rutgers University.

Core MD99-2317 was taken from the Grivel Basin, East Greenland ) (68.103°N, 27.8615°W, 536 m wd, 25.07 m long), offshore from the 60,000 km2 early Tertiary basalt outcrop, and from an area subjected to the transport of icebergs from local and regional tidewater glaciers. Radiocarbon dates for this core are reported in Jennings et al (2011). Grain size analysis of the 240 µm), volume % of sand, and measures of the sortable silt % and the mean sortable silt grain size, which can be correlated with changes in the flow speed of bottom currents . Tables 3 and 4 report replicate runs on X-ray diffraction estimates of mineral weight % and Malvern-based grain size volume % for a series of 7 paired samples (A versus B) taken across the 10-cm diameter core in order to investigate the variability of six non-clay and clay minerals and six grain size variables in adjacent samples. Between sample Analysis-of-Variance on the data set indicated only a limited number of statistically significant differences.