Abstract: To reconstruct climate history of the past 1.5 Million years, the project: Beyond EPICA Oldest Ice (BEOI) will drill about 2700 m of ice core in East Antarctica (2021–2025). As drilling fluid, an aliphatic ester fluid, EstisolTM 140, will be used. Newly drilled ice cores will be retrieved from the drill soaked in fluid, and this fluid should be removed from the cores. Most of it will be vacuum-cleaned off in a Fluid Extraction Device and wiped off with paper towels. Based on our experiences in Greenland deep ice coring, most of the residual fluid can be removed by storing the cores openly on shelves in a ventilated room. After a week of “drying”, the cores have a dry feel, handling them do not give “wet” gloves and they can easily be marked with lead pencils. This paper presents a theoretical investigation and some simple testing on the “drying” process. The rates of sublimation of ice and evaporation of fluid have been calculated at different temperatures. The calculations show that sublimation of the ice core should not occur, and that evaporation of fluid should be almost negligible. Our test results support these calculations, but also revealed significant fluid run-off and dripping, resulting in the removal of most of the fluid in a couple of days, independent of temperature and ventilation conditions. Finally, we discuss crucial factors that ensure optimal long-term ice core preservation in storage, such as temperature stability, defrosting cycles of freezers and open core storage versus storage of cores in insulated crates.

Abstract: Effective responses to rapid environmental change rely on observations to inform planning and decision-making. Reviewing literature from 124 programs across the globe and analyzing survey data for 30 Arctic community-based monitoring programs, we compare top-down, large-scale program driven approaches with bottom-up approaches initiated and steered at the community level. Connecting these two approaches and linking to Indigenous and local knowledge yields benefits including improved information products and enhanced observing program efficiency and sustainability. We identify core principles central to such improved links: matching observing program aims, scales, and ability to act on information; matching observing program and community priorities; fostering compatibility in observing methodology and data management; respect of Indigenous intellectual property rights and the implementation of free, prior, and informed consent; creating sufficient organizational support structures; and ensuring sustained community members’ commitment. Interventions to overcome challenges in adhering to these principles are discussed.

Abstract: Several recent dendrochronological, macrofossil and palynological studies have surveyed modern spruce forests at multiple locations in the Nain region of coastal Nunatsiavut (north-central Labrador) in order to reconstruct past forest composition, growth rates, species diversity and harvesting patterns. The present paper synthesizes original and previously collected data to evaluate the extent to which the dynamics of the region’s spruce forests over the past five centuries have been related to anthropogenic impacts. In three key case studies, Picea growth release events demonstrate multiple isolated forest disturbances prior to the late 19th century. In general, these events correspond to the local human settlement history rather than to regional climatic trends, suggesting that ongoing human impacts on the forest extend as far back as the 17th century. Disturbance regimes accelerated by ca 1875 and afterward in all of the study sites. This increase in forest disturbance corresponds to increased demands for wood triggered by socio-economic changes experienced by the region’s Inuit and Settler communities. Ongoing surveys demonstrate the presence of markers of human exploitation of forests throughout the study region, and especially in coastal locations, suggesting that anthropogenic impacts are in fact generalised and not limited to specific areas of recent settlement.

Abstract: In the framework of the GreenEdge Project (whose the general objective is to understand the dynamic of the phytoplankton spring bloom in Arctic Ocean), lipid composition and viability and stress state of bacteria were monitored in sea ice and suspended particulate matter (SPM) samples collected in 2016 along a transect from sea ice to open water in Baffin Bay (Arctic Ocean). Lipid analyses confirmed the dominance of diatoms in the bottommost layer of ice and suggested (i) the presence of a strong proportion of micro-zooplankton in SPM samples collected at the western ice covered St 403 and St 409 and (ii) a high proportion of macro-zooplankton (copepods) in SPM samples collected at the eastern ice covered St 413 and open water St 418. The use of the propidium monoazide (PMA) method allowed to show a high bacterial mortality in sea ice and in SPM material collected in shallower waters at St 409 and St 418. This mortality was attributed to the release of bactericidal free fatty acids by sympagic diatoms under the effect of light stress. A strong cis-trans isomerization of bacterial MUFAs was observed in the deeper SPM samples collected at the St 403 and St 409. It was attributed to the ingestion of bacteria stressed by salinity in brine channels of ice by sympagic bacterivorous microzooplankton (ciliates) incorporating trans fatty acids of their preys before to be released in the water column during melting. The high trans/cis ratios also observed in SPM samples collected in the shallower waters at St 413 and St 418 suggest the presence of positively or neutrally buoyant extracellular polymeric substances (EPS)-rich particles retained in sea ice and discharged (with bacteria stressed by salinity) in seawater after the initial release of algal biomass. Such EPS particles, which are generally considered as ideal vectors for bacterial horizontal distribution in the Arctic, appeared to contain a high proportion of dead and non-growing bacteria.

Abstract: This study aimed to quantify the impact of copepod grazing on the productivity of phytoplankton during an under sea-ice spring phytoplankton bloom (USPB) in western Baffin Bay. To quantify positive and/or negative impacts of copepod grazing on primary production and the interaction between copepod grazing and phytoplankton species, we sampled seawater and zooplankton under the landfast sea ice every 2–3 days between May 24 and July 10, 2016. Samples were analyzed for estimation of primary production, chlorophyll-a (chl-a) concentration, diatom abundance, and copepod fecal pellet (FP) production/grazing rate. Analyses of chl-a concentration, primary production, and FP production/grazing rate revealed clear temporal changes and a mismatch between primary production and copepod consumption. The FP production/grazing rate reached a maximum (9.4/31.2 mg C m–2 d–1) on June 16 before the USPB phase and suddenly decreased to 0.7/2.4 mg C m–2 d–1 on June 21, despite an increase in primary production to 74.0 mg C m–2 d–1. The copepod grazing rate (3.7 mg C m–2 d–1) was low relative to primary production (344.6 mg C m–2 d–1) during the USPB phase (after June 20). While our estimates illustrate that copepod grazing did not limit the maximum daily primary production during the USPB, the low grazing pressure (2% of primary production) may have been an additional contributor to the reduction in total primary productivity at the end of the USPB period due primarily to the low supply of regenerated nitrogen-containing nutrients to drive regenerated production.