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Nitrogen transformation processes in soil along a High Arctic tundra transect
Full text linkSoil nitrogen (N) transformation processes in the High Arctic tundra are poorly understood even though nitrogen is one of the main limiting nutrients. We analyzed soil samples collected along a High Arctic tundra transect to investigate spatial variability in key nitrogen transformation processes, functional gene abundances, ammonia-oxidizing archaea (AOA) community structures, and key nitrogen transformation regulators. The potential denitrification rates were higher than the nitrification rates in the soil samples, although nitrification may still regulate N2O emissions from tundra soil. The nutrient (total carbon, total organic carbon, total nitrogen, and 4 NH-N ) contents were important determinants of spatial variability in the potential denitrification rates of soil along the tundra transect. The total sulfur content was the main variable controlling potential nitrification processes, probably in association with sulfate-reducing bacteria. The nitrate content was the main variable affecting potential dissimilatory nitrate reduction to ammonium. AOA and ammonia-oxidizing bacteria amoA, nirS, and anammox 16S rRNA genes were found in all of the soil samples. AOA play more important roles than ammonia-oxidizing bacteria in soil nitrification. Anammox bacteria may utilize 2 NO produced through nitrification. Phylogenetic analysis indicated that the AOA amoA sequences could be grouped into eight unique operational taxonomic units (OTUs) with a 97% sequence similarity and were affiliated with three group 1.1b Nitrososphaera clusters. The results indicated that heterogeneous environmental factors (e.g., the carbon and nitrogen contents of soil) along the High Arctic tundra transect strongly affected the nitrogen transformation rate and relevant functional gene abundances in soil
Distributions of dissolved oxygen and apparent oxygen utilization in the Cosmonaut Sea and Amundsen Sea in austral summer 2021
Full text linkDissolved oxygen (DO) and apparent oxygen utilization (AOU) are crucial parameters for investigating marine ecosystem evolution and the marine environment. In this study, DO and AOU data were obtained and their spatial distribution characteristics were explored in the Cosmonaut Sea and Amundsen Sea in austral summer 2021. The standard deviation range of DO parallel samples was 160 μmol·L–1) could surge up to ca. 150–200 m in both seas, with stronger intrusion in the Amundsen Sea. The AOU in bottom water was significantly lower (p < 0.01) in the Cosmonaut Sea (118.9±11.8 μmol·L–1) than the Amundsen Sea (141.7±7.4 μmol·L–1), indicating the stable existence of fresh oxygen-rich Antarctic Bottom Water in the Cosmonaut Sea
Relating the composition of continental margin surface sediments from the Ross Sea to the Amundsen Sea, West Antarctica, to modern environmental conditions
Full text linkInvestigating the multiple proxies involving productivity, organic geochemistry, and trace element (TE) enrichment in surface sediments could be used as paleoenvironment archives to gain insights into past and future environmental conditions changes. We present redox-sensitive TEs (Mn, Ni, Cu, U, P, Mo, Co, V, Zn, and Cd), productivity-related proxies (total organic carbon and opal), and total nitrogen and CaCO3 contents of bulk surface sediments of this area. The productivity proxies from the shelf and coastal regions of the Ross and the Amundsen seas showed that higher productivity was affiliated with an area of nutrient-rich deep water upwelling. The upwelling of weakly corrosive deep water may be beneficial for preserving CaCO3, while highly corrosive dense water, if it forms on the shelf near the coastal region (coastal polynya), could limit the preservation of CaCO3 in modern conditions. There were no oxic or anoxic conditions in the study area, as indicated by the enrichment factors of redox-sensitive TEs (Mn, Co, and U). The enrichment factor of Cd, which is redox-sensitive, indicated suboxic redox conditions in sediment environments because of high primary productivity and organic matter preservation/decomposition. The enrichment factors of other redox-sensitive TEs (P, Ni, Cu, V, and Zn) and the correlations between the element/Ti ratio with productivity and nutrient proxies indicated that the organic matter decomposed, and there was massive burial of phytoplankton biomass. There was variation in the enrichment, such that sediments were enriched in P, Mo, and Zn, but depleted in Ni, Cu, and V
Meteorological and sea ice anomalies in the western Arctic Ocean during the 2018–2019 ice season: a Lagrangian study
Full text linkRapid changes in the Arctic climate and those in Arctic sea ice in recent decades are closely coupled. In this study, we used atmospheric reanalysis data and satellite remote sensing products to identify anomalies of meteorological and sea ice conditions during the ice season of 2018–2019 relative to climatological means using a Lagrangian methodology. We obtained the anomalies along the drifting trajectories of eight sea ice mass balance buoys between the marginal ice zone and the pack ice zone in the western Arctic Ocean (~160°W–170°W and 79°N–85°N) from September 2018 to August 2019. The temporary collapse of the Beaufort High and a strong positive Arctic Dipole in the winter of 2018–2019 drove the three buoys in the north to drift gradually northeastward and merge into the Transpolar Drift Stream. The most prominent positive temperature anomalies in 2018–2019 along the buoy trajectories relative to 1979–2019 climatology occurred in autumn, early winter, and April, and were concentrated in the southern part of the study area; these anomalies can be partly related to the seasonal and spatial patterns of heat release from the Arctic ice-ocean system to the atmosphere. In the southern part of the study area and in autumn, the sea ice concentration in 2018–2019 was higher than that averaged over the past 10 years. However, we found no ice concentration anomalies for other regions or seasons. The sea ice thickness in the freezing season and the snow depth by the end of the winter of 2018–2019 can also be considered as normal. Although the wind speed in 2018–2019 was slightly lower than that in 1979–2019, the speed of sea ice drift and its ratio to wind speed were significantly higher than the climatology. In 2019, the sea ice surface began to melt at the end of June, which was close to the 1988–2019 climatology. However, spatial variations in the onsets of surface melt in 2019 differed from the climatology, and can be explained by the prevalence of a high-pressure system in the south of the Beaufort Sea in June 2019. In addition to seasonal variations, the meteorological and sea ice anomalies were influenced by spatial variations. By the end of summer 2019, the buoys had drifted to the west of the Canadian Arctic Archipelago, where the ice conditions was heavier than those at the buoy locations in early September 2018. The meteorological and sea ice anomalies identified in this study lay the foundations for subsequent analyses and simulations of sea ice mass balance based on the buoy data
Population size and distribution of seabirds in the Cosmonaut Sea, Southern Ocean
Full text linkThe Cosmonaut Sea is one of the less studied ecosystems in the Southern Hemisphere. Unlike other seas which were near to coastal regions, however, few studies exist on the top predators in this zone. From December 2019 to January 2020, a survey of seabirds was carried out on the board icebreaker R/V Xuelong 2 in the Cosmonaut Sea and the Cooperation Sea. Twenty-three bird species were recorded. Antarctic petrel (Thalassoica antarctica), Antarctic prion (Pachyptila desolata), and Arctic tern (Sterna paradisaea) were the most abundant species. A total of about 37500 birds belonging to 23 species were recorded. Around 23% of the region had no record of birds. A large number of birds was recorded in 39°E–40°E, 44°E–46°E and 59°E–60°E. Many areas, such as 33°E–35°E, 39°E–41°E, 44°E–46°E and 59°E–60°E show a great richness. More than two-thirds of seabirds (71%) were observed in the zone near the ocean front. The prediction of the distributions of the most dominant species Antarctic petrel also showed that the area near the ocean front region had an important ecological significance for seabirds. The results suggest that the distribution of seabirds in the Cosmonaut Sea is highly heterogenous
Glasgow Financial Alliance for Net Zero - 2022 Progress Report
Full text linkThe Glasgow Financial Alliance for Net Zero (GFANZ) is a global coalition of leading financial institutions committed to mainstreaming the decarbonization of the global economy to reach net-zero emissions by 2050. Since its inception in April 2021, and through its practitioner-led work, drawing also on a network of climate experts and civil society organizations from around the world, GFANZ has worked to develop the tools and methodologies needed to turn financial institutions’ net-zero commitments into action, drawing on and amplifying the enormously valuable work of the many organizations that have driven climate action
for years.
This report highlights the significant progress and accomplishments of GFANZ to date
Directory of European Polar Research Funding Programmes
Full text linkThe polar regions are sentinels of climate change and human resilience and they are also a proven bastion for international cooperation in research and nature protection. European researchers have made significant contributions to understand the consequences of climate change and the structure and functioning of ecosystems at both polar regions, and their global interconnections. Unifying, disseminating and coordinating all European research actions is one of the tasks of the EU-PolarNet 2 project. EU-PolarNet 2 – “Coordinating and co-designing the European Polar Research Area” is a coordination and support action funded by the European Commission in Horizon 2020. It comprises 25 partners representing all European and associated countries with well-developed Polar research programmes and activities.
EU-PolarNet 2 aims to provide a platform to co-develop strategies to advance European polar research and its contribution to policy-making processes. By involving all relevant stake- and rightsholders it supports the development of transdisciplinary and transnational polar research actions of high societal relevance. To ensure that such an important platform is sustained after the four years of project duration, the project works with funding agencies, national polar research institutes, operators of national polar programmes, polar experts and the European polar research community to discuss and implement the identified research actions. The final goal of EU-PolarNet 2 is to create a permanent European Polar Coordination Office which will continue the work of EU-PolarNet 2 in a sustained wa
Variability of size-fractionated phytoplankton standing stock in the Amundsen Sea during summer
Full text linkThe size-fractionated composition of phytoplankton greatly influences the transfer efficiency of biomass in pelagic food chains and the biological carbon flux from surface waters to the deep sea. To better understand phytoplankton abundance and composition in polynya, ice zone, and open ocean regions of the Amundsen Sea Sector of the Southern Ocean (110°W–150°W), its size-fractionated distribution and vertical structure are reported for January to February 2020. Vertical integrated (0–200 m) chlorophyll (Chl) a concentrations within Amundsen polynya regions are significantly higher than those within ice zone (t test, p 20 μm) contribute 60% of the total Chl in Amundsen polynya and sea ice areas, and form subsurface chlorophyll maxima (SCM) above the pycnocline in the upper water column, probably because of diatom blooms. Net-, nano-, and picoplankton comprise 39%, 32%, and 29% of total Chl in open ocean stations, respectively. The open-ocean SCM migrates deeper and is below the pycnocline. The Amundsen Sea SCM is moderately, positively correlated with the euphotic zone depth and moderately, negatively correlated with column-integrated net- and nanoplankton Chl
Bacterial community diversity of meltwater runoff and soil in Midre Lovénbreen glacier in Ny-Ålesund, Arctic
Full text linkGlacial meltwater runoff is a dynamic ecosystem. On the one hand, nutrient concentration changes as it flows from upstream to downstream, and on the other hand, bacterial community structure changes due to its contact with nearby soil during the flow process. We studied meltwater and soil in the Midre Lovénbreen glacier region, to explore changes in bacterial diversity as meltwater flows, and the relationship between meltwater and soil bacterial diversity. As glacial meltwater flows from upstream to downstream, the relative abundance of dominant bacterial groups changes. In addition, we found that during the flowing process, nutrient exchange and bacterial contact had occurred between the meltwater runoff and the soil. As a result, the distribution patterns of some bacteria in the meltwater are very similar to those in the soil. Finally, we combined distance-based redundancy analysis and weighted correlation network analysis to show that NO3 −-N and NO2 −-N are the most two significant factors affecting glacial meltwater and soil, respectively. Our results suggest that in such a close-knit ecosystem, the interaction of glacial meltwater with soil, as well as environmental factors, together determine bacterial community composition