Snowmelt contribution to Arctic first-year ice ridge mass balance and rapid consolidation during summer melt

Sea ice ridges are one of the most under-sampled and poorly understood components of the Arctic sea ice system. Yet, ridges play a crucial role in the sea ice mass balance and have been identified as ecological hotspots for ice-associated flora and fauna in the Arctic. To better understand the mass balance of sea ice ridges, we drilled and sampled two different first-year ice (FYI) ridges in June–July 2020 during the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC). Ice cores were cut into 5 cm sections, melted, then analyzed for salinity and oxygen (d18O) isotope composition. Combined with isotope data of snow samples,we used a mixing model to quantify the contribution of snow to the consolidated sea ice ridge mass. Our results demonstrate that snow meltwater is important for summer consolidation and overall ice mass balance of FYI ridges during the melt season, representing 6%–11% of total ridged ice mass or an ice thickness equivalent of 0.37–0.53 m.These findings demonstrate that snowmelt contributes to consolidation of FYI ridges and is a mechanism resulting in a relative increase of sea ice volume in summer. This mechanism can also affect the mechanical strength and survivability of ridges, but also contribute to reduction of the habitable space and light levels within FYI ridges. We proposed a combination of two pathways for the transport of snow meltwater and incorporation into ridge keels: percolation downward through the ridge and/or lateral transport from the under-ice meltwater layer. Whether only one pathway or a combination of both pathways is most likely remains unclear based on our observations, warranting further research on ridge morphologypublishedVersio

Roadmap on emerging concepts in the physical biology of bacterial biofilms: from surface sensing to community formation

Bacterial biofilms are communities of bacteria that exist as aggregates that can adhere to surfaces or be free-standing. This complex, social mode of cellular organization is fundamental to the physiology of microbes and often exhibits surprising behavior. Bacterial biofilms are more than the sum of their parts: single-cell behavior has a complex relation to collective community behavior, in a manner perhaps cognate to the complex relation between atomic physics and condensed matter physics. Biofilm microbiology is a relatively young field by biology standards, but it has already attracted intense attention from physicists. Sometimes, this attention takes the form of seeing biofilms as inspiration for new physics. In this roadmap, we highlight the work of those who have taken the opposite strategy: we highlight the work of physicists and physical scientists who use physics to engage fundamental concepts in bacterial biofilm microbiology, including adhesion, sensing, motility, signaling, memory, energy flow, community formation and cooperativity. These contributions are juxtaposed with microbiologists who have made recent important discoveries on bacterial biofilms using state-of-the-art physical methods. The contributions to this roadmap exemplify how well physics and biology can be combined to achieve a new synthesis, rather than just a division of labor

Ice thickness, growth and salinity in Van Mijenfjorden, Svalbard, Norway

This paper describes measurements of ice conditions in the fjord Van Mijenfjorden, Spitsbergen, in the Svalbard Archipelago, between 1998 and 2006. Ice thickness, ice temperatures and ice properties were measured, and simple simulations of oceanic flux were performed. The maximum annual peak ice thickness was measured in 2004: 1.3 m in the inner basin and 1.2 m in the outer basin. The minimum annual peak thickness was 0.72 m in the inner basin and no fast ice in the outer basin, in 2006. The estimated oceanic flux was about 2–5 W m-2 in the outer basin, and was close to zero in the inner basin. Flooding and brine drainage may have caused an overestimation of the oceanic flux. The measurements demonstrate different ice growth mechanisms, and the simplest model (Stefan’s Law with air temperatures and a correction factor) fails to predict the ice growth. Finally, there is reason to believe that the ice conditions were heavier in the 1980s

Svalbard fjord environments with land-fast sea ice as arenas for climate research, monitoring, remote sensing validation, and dedicated process studies

acceptedVersio

Calibration data for Infratructure mapping in Svalbard, link to files

This dataset contains geographical features representing selected infrastructures (houses, roads, airfield, pipelines etc.) in the town Longyearbyen on Svalbard. Each feature has attributes listing relevant classifiers, such as: - the type of infrastructure (residential building, road, pipeline, etc.) - the shape of the feature (flat, sloped, pitched, domed, barrel-shaped) - the type of surface material (wood, concrete, asphalt, etc.) - the background setting (rock, sediments, sea, etc.) - its current status as actively used or inactive infrastructure. -- All feature locations and attributes have been validated either by on-site inspection, or by Google Street View imagery (validation method indicated in feature attributes). -- Photos are provided for most of the features that were field validated

Drill-hole ridge ice and snow thickness and draft measurements of "Fort Ridge" during MOSAiC 2019/20

Snow and first-year sea ice ridge thickness, draft and morphology were measured using a 2-inch ice drilling auger (Kovacs Enterprises) during walking surveys on first-year ice ridge during the MOSAiC expedition. Drilling was performed during January and February 2020 across three drilling transects located 20 m from each other. The investigated "Fort Ridge" was formed from late September to early October 2019 between second- and first-year ice. It was approximately 90–100 m long and 20–30 m wide. The ridge was located on drifting sea ice in the Arctic Ocean within the Central Observatory of MOSAiC. The table contains the event label (1), event ID (2), time (3), and global coordinates (4,5) of each drilling measurement. Each separate drilling hole has its number indicating cross-section and number within cross-section (6), and local coordinate X (7) in [m] and transect name (8). Global coordinates are given for the local coordinates of X = 22 m at the transect 1. For each drill hole, the depth relative to the waterline of the top (9) and bottom (10) interface of each separate layer is given together with its ice type (11). Ice types include snow, ice (with various resistance), and voids. Information about missing freeboard measurements is given in comments (12). In the case of no freeboard measurement, it was assumed as 10% of the maximum keel draft. The drill hole with local coordinates of X = 22 m at the transect 1 coincides with the ice mass balance buoy 2020T60 installation described in doi:10.1594/PANGAEA.924269. These measurements were performed as part of the project Ridges - Safe HAVens for ice-associated Flora and Fauna in a Seasonally ice-covered Arctic OCean (HAVOC), funded by the Research Council of Norway, project number: 280292)