Highly resolved temporal and spatial distributions of trace elements in ocean water can provide insight into ocean processes but carry a significant analytical demand which requires methods that combine accuracy and precision with high sample throughput. Here a multi-element method is presented which combines the commercially-available seaFAST preconcentration system with ICP-MS/MS for the analysis of Mn, Fe, Ni, Cu, Zn, Cd and Pb in seawater. Samples (20 mL or 40 mL) are loaded on to a chelation resin column and trace metals eluted into 2.5 mL of 1.6 N HNO₃. Analysis of the eluate was carried out by ICP-MS/MS, which combines two mass-selecting quadrupoles separated by an octopole collision/reaction cell. The collision/reaction cell was pressurized with O₂ gas for the analysis of Mn, Ni, Cu, Cd and Pb and H₂ gas for the analysis of Fe and Zn, which removed common interferences (e.g. ArO⁺ on ⁵⁶Fe and MoO⁺ on Cd) yet maintained the highest instrument sensitivity across the entire mass range. Measured blanks and detection limits were ≤0.050 nmol L⁻¹ levels, except for the Fe (blank 0.14 nmol L⁻¹) and were suitable for open-ocean seawater analysis. We report results for the certified reference material NASS-6, consensus reference standards SAFe S and SAFe D and depth profiles of trace metals from the Arctic Ocean, collected as part of the Canadian GEOTRACES program.

Water stable isotope records from ice cores (δ¹⁸O and δD) are a critical tool for constraining long-term temperature variability at high latitudes. However, precipitation in Antarctica consists of semi-continuous small events and intermittent extreme events. In regions of high accumulation, this can bias ice core records towards recording the synoptic climate conditions present during extreme precipitation events. In this study we utilise a combination of ice core data, reanalysis products, and models to understand how precipitation intermittency impacts the temperature records preserved in an ice core from Mount Brown South in East Antarctica. Extreme precipitation events represent only the largest 10 % of all precipitation events, but they account for 52 % of the total annual snowfall at this site, leading to an overrepresentation of these events in the ice core record. Extreme precipitation events are associated with high-pressure systems in the mid-latitudes that cause increased transport of warm and moist air from the southern Indian Ocean to the ice core site. Warm temperatures associated with these events result in a +4.8 ^∘C warm bias in the mean annual temperature when weighted by daily precipitation, and water isotopes in the Mount Brown South ice core are shown to be significantly correlated with local temperature when this precipitation-induced temperature bias is included. The Mount Brown South water isotope record spans more than 1000 years and will provide a valuable regional reconstruction of long-term temperature and hydroclimate variability in the data-sparse southern Indian Ocean region.

The Arctic Ocean is considered a source of micronutrients to the Nordic Seas and the North Atlantic Ocean through the gateway of Fram Strait (FS). However, there is a paucity of trace element data from across the Arctic Ocean gateways, and so it remains unclear how Arctic and North Atlantic exchange shapes micronutrient availability in the two ocean basins. In 2015 and 2016, GEOTRACES cruises sampled the Barents Sea Opening (GN04, 2015) and FS (GN05, 2016) for dissolved iron (dFe), manganese (dMn), cobalt (dCo), nickel (dNi), copper (dCu) and zinc (dZn). Together with the most recent synopsis of Arctic‐Atlantic volume fluxes, the observed trace element distributions suggest that FS is the most important gateway for Arctic‐Atlantic dissolved micronutrient exchange as a consequence of Intermediate and Deep Water transport. Combining fluxes from FS and the Barents Sea Opening with estimates for Davis Strait (GN02, 2015) suggests an annual net southward flux of 2.7 ± 2.4 Gg·a⁻¹ dFe, 0.3 ± 0.3 Gg·a⁻¹ dCo, 15.0 ± 12.5 Gg·a⁻¹ dNi and 14.2 ± 6.9 Gg·a⁻¹ dCu from the Arctic toward the North Atlantic Ocean. Arctic‐Atlantic exchange of dMn and dZn were more balanced, with a net southbound flux of 2.8 ± 4.7 Gg·a⁻¹ dMn and a net northbound flux of 3.0 ± 7.3 Gg·a⁻¹ dZn. Our results suggest that ongoing changes to shelf inputs and sea ice dynamics in the Arctic, especially in Siberian shelf regions, affect micronutrient availability in FS and the high latitude North Atlantic Ocean.

Investigation of organic compounds in ice cores can potentially unlock a wealth of new information in these climate archives. We present results from the first ever ice core drilled on sub‐Antarctic island Bouvet, representing a climatologically important but understudied region. We analyze a suite of novel and more familiar organic compounds in the ice core, alongside commonly measured ions. Methanesulfonic acid shows a significant, positive correlation to winter sea ice concentration, as does a fatty acid compound, oleic acid. Both may be sourced from spring phytoplankton blooms, which are larger following greater sea ice extent in the preceding winter. Oxalate, formate, and acetate are positively correlated to sea ice concentration in summer, but sources of these require further investigation. This study demonstrates the potential application of organic compounds from the marine biosphere in generating multiproxy sea ice records, which is critical in improving our understanding of past sea ice changes.

The climate of the sub-Antarctic is important in understanding the environmental conditions of Antarctica and the Southern Ocean. However, regional climate proxy records from this region are scarce. In this study, we present the stable water isotopes, major ion chemistry, and dust records from the first ice core from the (sub-)Antarctic Young Island. We present and discuss various dating approaches based on commonly used ice core proxies, such as stable water isotopes and seasonally deposited ions, together with site-specific characteristics such as melt layers. The dating approaches are compared with estimated precipitation rates from reanalysis data (ERA5) and volcanic cryptotephra shards likely presenting an absolute tie point from a 2001 CE eruption on neighboring Sturge Island. The resulting ice core age scale spans the period 2016 to 1995, with an uncertainty of ±2 years.