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In this letter, we introduce The Polar Vocabularies and Semantics Working Group, originally established as a joint effort between the joint SAON/IASC Arctic Data Committee and the Data Management Collaboration Team of the Interagency Arctic Research Policy Committee. We Invite, communities of practice to actively engage with us in our activities (described below), to advance the state of semantics-based applications in polar activities (and to increase interoperability between stakeholders and rights holders within existing and emerging digital ecosystems).

This dataset includes the NEMO 4.0.2 configuration used and analysed in the paper titled "Eddy-driven heterogeneity in sea ice during the ice-growth season". The output data is approximately 4TB for the 3 idealised configuration used in the manuscript, thus we opted to distribute the configuration. Note: The initial conditions for each simulation are compressed into the file `init_cond.zip` The configuration for one of the simulations is compressed in the file `config.zip` In order to reproduce all the runs, it's only required to change the initial conditions in the file namelist_cfg and namelist_ice_cfg. Further information and scripts to reproduce the result of the manuscript can be found at: https://github.com/josuemtzmo/Ice_formation

We combine consistently dated benthic carbon isotopic records distributed over the entire Atlantic Ocean with numerical simulations performed by a glacial configuration of the Norwegian Earth System Model with active ocean biogeochemistry, in order to interpret the observed Cibicides δ13C changes at the stadial-interstadial transition corresponding to the end of Heinrich Stadial 4 (HS4) in terms of ocean circulation and remineralization changes. We show that the marked increase in Cibicides δ13C observed at the end of HS4 between ~2000 and 4200 m in the Atlantic can be explained by changes in nutrient concentrations as simulated by the model in response to the halting of freshwater input in the high latitude glacial North Atlantic. Our model results show that this Cibicides δ13C signal is associated with changes in the ratio of southern-sourced (SSW) versus northern-sourced (NSW) water masses at the core sites, whereby SSW is replaced by NSW as a consequence of the resumption of deep water formation in the northern North Atlantic and Nordic Seas after the freshwater input is halted. Our results further suggest that the contribution of ocean circulation changes to this signal increases from ~40 % at 2000 m to ~80 % at 4000 m. Below ~4200 m, the model shows little ocean circulation change but an increase in remineralization across the transition marking the end of HS4. The simulated lower remineralization during stadials than interstadials is particularly pronounced in deep subantarctic sites, in agreement with the decrease in the export production of carbon to the deep Southern Ocean during stadials found in previous studies.

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This study presents simulations of Greenland surface melt for the Eemian interglacial period (∼130 000 to 115 000 years ago) derived from regional climate simulations with a coupled surface energy balance model. Surface melt is of high relevance due to its potential effect on ice core observations, e.g., lowering the preserved total air content (TAC) used to infer past surface elevation. An investigation of surface melt is particularly interesting for warm periods with high surface melt, such as the Eemian interglacial period. Furthermore, Eemian ice is the deepest and most compressed ice preserved on Greenland, resulting in our inability to identify melt layers visually. Therefore, simulating Eemian melt rates and associated melt layers is beneficial to improve the reconstruction of past surface elevation. Estimated TAC, based on simulated melt during the Eemian, could explain the lower TAC observations. The simulations show Eemian surface melt at all deep Greenland ice core locations and an average of up to ∼30 melt days per year at Dye-3, corresponding to more than 600 mm water equivalent (w.e.) of annual melt. For higher ice sheet locations, between 60 and 150 mmw.e.yr-1 on average are simulated. At the summit of Greenland, this yields a refreezing ratio of more than 25 % of the annual accumulation. As a consequence, high melt rates during warm periods should be considered when interpreting Greenland TAC fluctuations as surface elevation changes. In addition to estimating the influence of melt on past TAC in ice cores, the simulated surface melt could potentially be used to identify coring locations where Greenland ice is best preserved.

Rivers are major pathways of plastics from lands into the Ocean. However, there is still a huge lack of knowledge on how riverine litter, including macroplastics, is transferred into the Ocean. Quantitative measurements of macroplastic emissions in rivers even suggest that a small fraction (0.001 to 3%) of the Mismanaged Plastic Waste (MPW) generated within a river basin finally reach the sea. Instead, macroplastics may remain within the catchment and on coastlines because of complex transport dynamics that delay the transfer of plastic debris. In order to better understand those dynamics, we performed tracking of riverine litter over time. First, hundreds of date-prints items were collected on riverbanks in the Seine estuary. The distribution of their Use-By-Dates suggest that riverine litter may remain stored on riverbanks for decades. Second, we performed real time tracking of floating and sub-floating bottles using GPS-trackers. Between March 2018 and April 2019, 39 trajectories were recorded in the estuary under tidal influence and 11 trajectories upriver, covering a wide range of hydrometeorological conditions. Results show a succession of stranding/remobilization episodes in combination with alternating upstream and downstream transport in the estuary related to tides. In the end, tracked bottles systematically stranded somewhere, for hours to weeks, from one to several times on different sites. The overall picture shows that different hydrometeorological phenomena interact with various time scales ranging from hours/days (high/low tides) to weeks/months (spring/neap tides and highest tides) and years (seasonal river flow, vegetation and geomorphological aspects). Thus, the fate of plastic debris is highly unpredictable with a chaotic-like transfer of plastic debris into the Ocean. The residence time of these debris is much longer than the transit time of water. This offers the opportunity to collect them before they get fragmented and/or reach the Sea.

The shallower oxygen-poor water masses of the ocean confine a majority of the microbial communities that can produce up to 90 % of oceanic N2. This effective N2-yielding section encloses a suspended small-particle layer, inferred from particle backscattering (bbp) measurements. It is thus hypothesized that this layer (hereafter, the bbp-layer) is linked to microbial communities involved in N2 yielding such as nitrate-reducing SAR11 as well as sulfur-oxidizing, anammox, and denitrifying bacteria – a hypothesis yet to be evaluated. Here, data collected by three BGC-Argo floats deployed in the Black Sea are used to investigate the origin of this bbp-layer. To this end, we evaluate how the key drivers of N2-yielding bacteria dynamics impact the vertical distribution of bbp and the thickness of the bbp-layer. In conjunction with published data on N2 excess, our results suggest that the bbp-layer is at least partially composed of the bacteria driving N2 yielding for three main reasons: (1) strong correlations are recorded between bbp and nitrate; (2) the top location of the bbp-layer is driven by the ventilation of oxygen-rich subsurface waters, while its thickness is modulated by the amount of nitrate available to produce N2; and (3) the maxima of both bbp and N2 excess coincide at the same isopycnals where bacteria involved in N2 yielding coexist. We thus advance that bbp and O2 can be exploited as a combined proxy to delineate the N2-yielding section of the Black Sea. This proxy can potentially contribute to refining delineation of the effective N2-yielding section of oxygen-deficient zones via data from the growing BGC-Argo float network.

The ICES Working Group on the History of Fish and Fisheries (WGHIST) is a forum for interdisciplinary research on social-ecological change in marine and fisheries systems over multi-decadal to centennial timescales.WGHIST comprises a diverse group of researchers, including marine biologists, fisheries scientists, historians, and historical ecologists, from Europe and North America, as well as Australia, Russia, and South Africa. WGHIST provided a platform for the sharing and reporting of a wide range of research on marine and fisheries systems change over time, including the use of novel and non-traditional data sources and methodologies to identify and interpret these changes. WGHIST members also worked with the ICES Secretariat to forward digital tools to make historical resources more accessible and regarding WGHIST’s potential to support ICES Fisheries and Ecosystem Overviews.WGHIST engaged with the larger research community on the following manuscripts, still in development or recently submitted: (1) the acute value of the past in the Anthropocene; (2) the importance of and advice on cross-disciplinary conversations; (3) the legacy of Sidney Holt; (4) the power and consequence of qualitative information; and (5) the social and cultural drivers of technology creep.Finally, WGHIST found extensive evidence for defining elements of blue growth in the past, and explored examples from around the world to delineate lessons for today’s blue growth agendas, research now published in Fish and Fisheries. Future work will forward additional digital tools to access historical resources, develop links to other related data resources, and progress connections between lessons from the past and contemporary management and policy.

The ICES Working Group on the History of Fish and Fisheries (WGHIST) is a forum for interdisciplinary research on social-ecological change in marine and fisheries systems over multi-decadal to centennial timescales.WGHIST comprises a diverse group of researchers, including marine biologists, fisheries scientists, historians, and historical ecologists, from Europe and North America, as well as Australia, Russia, and South Africa. WGHIST provided a platform for the sharing and reporting of a wide range of research on marine and fisheries systems change over time, including the use of novel and non-traditional data sources and methodologies to identify and interpret these changes. WGHIST members also worked with the ICES Secretariat to forward digital tools to make historical resources more accessible and regarding WGHIST’s potential to support ICES Fisheries and Ecosystem Overviews.WGHIST engaged with the larger research community on the following manuscripts, still in development or recently submitted: (1) the acute value of the past in the Anthropocene; (2) the importance of and advice on cross-disciplinary conversations; (3) the legacy of Sidney Holt; (4) the power and consequence of qualitative information; and (5) the social and cultural drivers of technology creep.Finally, WGHIST found extensive evidence for defining elements of blue growth in the past, and explored examples from around the world to delineate lessons for today’s blue growth agendas, research now published in Fish and Fisheries. Future work will forward additional digital tools to access historical resources, develop links to other related data resources, and progress connections between lessons from the past and contemporary management and policy.

As part of the Model Intercomparison Project on the climatic response to Volcanic forcing (VolMIP), several climate modeling centers performed a coordinated pre-study experiment with interactive stratospheric aerosol models simulating the volcanic aerosol cloud from an eruption resembling the 1815 Mt. Tambora eruption (VolMIP-Tambora ISA ensemble). The pre-study provided the ancillary ability to assess intermodel diversity in the radiative forcing for a large stratospheric-injecting equatorial eruption when the volcanic aerosol cloud is simulated interactively. An initial analysis of the VolMIP-Tambora ISA ensemble showed large disparities between models in the stratospheric global mean aerosol optical depth (AOD). In this study, we now show that stratospheric global mean AOD differences among the participating models are primarily due to differences in aerosol size, which we track here by effective radius. We identify specific physical and chemical processes that are missing in some models and/or parameterized differently between models, which are together causing the differences in effective radius. In particular, our analysis indicates that interactively tracking hydroxyl radical (OH) chemistry following a large volcanic injection of sulfur dioxide (SO2) is an important factor in allowing for the timescale for sulfate formation to be properly simulated. In addition, depending on the timescale of sulfate formation, there can be a large difference in effective radius and subsequently AOD that results from whether the SO2 is injected in a single model grid cell near the location of the volcanic eruption, or whether it is injected as a longitudinally averaged band around the Earth.