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Copyright of Atmosphere -- Ocean (Taylor & Francis Ltd) is the property of Taylor & Francis Ltd and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of the Japanese Society of Snow & Ice / Seppyo is the property of Japanese Society of Snow & Ice and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The biodiversity, ecosystem services and climate variability of the Antarctic continent and the Southern Ocean are major components of the whole Earth system. Antarctic ecosystems are driven more strongly by the physical environment than many other marine and terrestrial ecosystems. As a consequence, to understand ecological functioning, cross-disciplinary studies are especially important in Antarctic research. The conceptual study presented here is based on a workshop initiated by the Research Programme Antarctic Thresholds – Ecosystem Resilience and Adaptation of the Scientific Committee on Antarctic Research, which focussed on challenges in identifying and applying cross-disciplinary approaches in the Antarctic. Novel ideas and first steps in their implementation were clustered into eight themes. These ranged from scale problems, through risk maps, and organism/ecosystem responses to multiple environmental changes and evolutionary processes. Scaling models and data across different spatial and temporal scales were identified as an overarching challenge. Approaches to bridge gaps in Antarctic research programmes included multi-disciplinary monitoring, linking biomolecular findings and simulated physical environments, as well as integrative ecological modelling. The results of advanced cross-disciplinary approaches can contribute significantly to our knowledge of Antarctic and global ecosystem functioning, the consequences of climate change, and to global assessments that ultimately benefit humankind. [ABSTRACT FROM AUTHOR]

The seasonality of carbon dioxide partial pressure ( p CO 2 ), air-sea CO 2 fluxes and associated environmental parameters were investigated in the Antarctic coastal waters. The in-situ survey was carried out from the austral summer till the onset of winter (January 2012, February 2010 and March 2009) in the Enderby Basin. Rapid decrease in p CO 2 was evident under the sea-ice cover in January, when both water column and sea-ice algal activity resulted in the removal of nutrients and dissolved inorganic carbon (DIC) and increase in pH. The major highlight of this study is the shift in the dominant biogeochemical factors from summer to early winter. Nutrient limitation (low Si/N), sea-ice cover, low photosynthetically active radiation (PAR), deep mixed layer and high upwelling velocity contributed towards higher p CO 2 during March (early winter). CO 2 fluxes suggest that the Enderby Basin acts as a strong CO 2 sink during January (−81 mmol m −2 d −1 ), however it acts as a weak sink of CO 2 with −2.4 and −1.7 mmol m −2 d −1 during February and March, respectively. The present work, concludes that sea ice plays a dual role towards climate change, by decreasing sea surface p CO 2 in summer and enhancing in early winter. Our observations emphasize the need to address seasonal sea-ice driven CO 2 flux dynamics in assessing Antarctic contributions to the global oceanic CO 2 budget. [ABSTRACT FROM AUTHOR]

We present worst-case assessments of contamination in sea ice and surface waters resulting from hypothetical well blowout oil spills at ten sites in the Arctic Ocean basin. Spill extents are estimated by considering Eulerian passive tracers in the surface ocean of the MITgcm (a hydrostatic, coupled ice-ocean model). Oil in sea ice, and contamination resulting from melting of oiled ice, is tracked using an offline Lagrangian scheme. Spills are initialized on November 1st 1980–2010 and tracked for one year. An average spill was transported 1100 km and potentially affected 1.1 million km 2 . The direction and magnitude of simulated oil trajectories are consistent with known large-scale current and sea ice circulation patterns, and trajectories frequently cross international boundaries. The simulated trajectories of oil in sea ice match observed ice drift trajectories well. During the winter oil transport by drifting sea ice is more significant than transport with surface currents. [ABSTRACT FROM AUTHOR]

The Hudson Bay exerts a strong advective influence on the surface energy balance of the adjacent Hudson Bay Lowlands (HBL) of Canada. The onshore winds are relatively cold and moist compared to the warmer and drier offshore winds. The contrasting thermal and humidity properties of these two air masses affect the partitioning of net radiation between the various heat fluxes over the HBL. We show that global warming has been accompanied by significant changes in the mesoscale wind regimes and the advective role of the Hudson Bay on the surface energy balance over the HBL. On average, we found a significant increasing trend in onshore wind frequency during the growing season of about 7% over the past 40 years. The most pronounced increase in onshore winds of 17% occurred in June during which ice cover on Hudson Bay has remained highly persistent over the past 40 years. The resulting shift from offshore to onshore winds dominance over the region has resulted in an enhancement of convective heat transfer to the atmosphere and a reduction of conductive heat transfer into the ground. [ABSTRACT FROM AUTHOR]

The article discusses research done on the impact of environmental disturbance on sea-ice microbial communities. Primary and secondary production in ice-covered regions of the Southern Ocean are associated with sea-ice microbial communities. A reciprocal transplant experiment was conducted within Antarctic fast-ice in order to analyze the response of sea-ice microbes to key physiochemical variables. The study procedure also included the extraction of a series of ice cores from a 2.9-meter (m) annual ice.

The distribution of diatom taxa was studied in the Enderby Basin, East Antarctica during the austral summer of 2010. In this study, the influence of freshwater at east of the 55°E was observed due to the melting of sea-ice, resulting in stratified (shallow Mixed Layer Depth (MLD)) and low saline conditions. This decrease in sea-surface salinity was associated with an increase in p CO 2 and decrease in total diatom abundance. Corethron criophilum was recognized as the most abundant diatom (absolute abundance up to 30 × 104 cells L−1; 35% contribution to total diatom taxa) and its elevated abundances recorded at west of the 55°E. Reduced C. criophilum and increased abundances of Fragilariopsis curta and Thal assiothrix antarctica were documented at east of the 55oE. This study shows that despite shallow MLD and macronutrient availability, the diatom abundance at east of 55oE was low. We suspect that, the factors such as micronutrient unavailability, freshening of the upper water column, transportation by water masses, and photoinhibition possibly affect the production of diatoms at east of the 55oE. The elevated abundance of diatoms to the west of the 55°E resulted in low pCO 2 levels and high meso-zooplankton abundance. This study suggests the need of long term monitoring of phytoplankton community structure and factors influencing their production in the East Antarctic region. This is essential to better understand the projected effects of physico-chemical conditions (especially pCO 2 and temperature) on Southern Ocean phytoplankton and thus biological carbon pump. • Sea-ice melting driven low salinity was associated with low diatom abundance. • criophilum is the most abundant diatom with 35% contribution to total diatom. • Despite shallow MLD the diatom abundance was low. • Only few diatom species were benefitted from Sea-ice melting. • Sea-ice melting could affect Antarctic food web dynamics. [ABSTRACT FROM AUTHOR]

The fast receding sea-ice extent in the Arctic Ocean (AO) has implications for the global climate. Changes in the sea-ice dynamics cause variations in ocean physical and biogeochemical parameters. An ensemble of simulations from the 'Community Earth System Model' (CESM2-WACCM), part of the sixth phase of the Coupled Model Intercomparison Project (CMIP6), is utilized for years 1850–2100. The regional differences in sea-ice parameters are highlighted over seven marginal seas in the AO. The maximum difference in sea-ice heat content (~4.5 × 108 J m−2) is obtained in the East Siberian Sea, central AO, and along the east coast of Greenland in March. The sea surface temperature has higher temporal variability in the Barents Sea, Beaufort Sea and Chukchi Sea in September, which confines the Fram Strait and the Barents Sea regions in March. In September, the sea-ice concentration shows large (>30%) temporal variations in the East Siberian Sea, Laptev Sea, Beaufort Sea, and along the coast of Greenland. Sea surface temperature is projected to increase by 6 °C over the Chukchi Sea by the year 2100. In response to sea-ice melting, a decline in sea-ice thickness and reduction of sea surface salinity up to 2.5 psu is observed in the future relative to the present in some parts of the AO. The advection of Atlantic water and its wind-driven mixing causes maximum winter-time warming in the Svalbard region over the eastern Greenland Sea. The future projections indicate the ice-free surface during September in the AO by the year 2050. [ABSTRACT FROM AUTHOR]