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The adaptation of Arctic phytoplankton to low light and salinity in Kongsfjorden (Spitsbergen)
Get PDFThe basic environmental variables and adaptability of phytoplankton communities to low light and salinity were studied using incubation experiments in Kongsfjorden, a high Arctic fjord of Spitsbergen, in late summer 2006. Chlorophyll a concentrations were steady or decreased slightly in darkness after one day or one week incubation. Chlorophyll a concentrations showed an initial decline when exposed to natural light after one week incubation in darkness, and then increased significantly. In a salinity experiment, the maximal growth rate was observed at a dilution ratio of 10%, however, higher dilution ratios (≥40%) had an obvious negative effect on phytoplankton growth. We suggest that the phytoplankton communities in fjords in late summer are darkness adapted, and the inflow of glacial melt water is favorable for phytoplankton growth in the outer fjords where the influence of freshwater is limited
Development of the geodetic coordinate system in Antarctica
Get PDFDefining a universal geodetic coordinate system is one of the fundamental challenges of geodesy. We present a review of the basic general coordinate systems — the space rectangular coordinate system, the geodetic coordinate system, the topocentric coordinate system, and the plane coordinate system. We then look at the World Geodetic System WGS72 and WGS84 and the International Terrestrial Reference Frames ITRF2000 and ITRF2005, which were introduced when space technology became available. The history of international geodetic coordinate systems in the Antarctic region is briefly reviewed and the development of the geodetic coordinate systems in the Chinese Great Wall Station and Zhongshan Station in Antarctica is outlined. Finally, the issue of coordinate system transformation is discussed
Simultaneous optical and radar observations of poleward moving auroral forms under different IMF conditions
Get PDFUsing high temporal resolution optical data obtained from three-wavelength all-sky imagers at Chinese Yellow River Station in the Arctic, together with the EISCAT Svalbard radar (ESR) and SuperDARN radars, we investigated the dayside poleward moving auroral forms (PMAFs) and the associated plasma features in the polar ionosphere under different interplanetary magnetic field (IMF) conditions, between 0900 and 1010 UT on 22 December 2003. Simultaneous optical and ESR observations revealed that all PMAFs were clearly associated with pulsed particle precipitations. During northward IMF, particles can precipitate into lower altitudes and reach the ionospheric E-region, and there is a reverse convection cell associated with these PMAFs. This cell is one of the typical signatures of the dayside high-latitude (lobe) reconnection in the polar ionosphere. These results indicate that the PMAFs were associated with the high-latitude reconnection. During southward IMF, the PMAFs show larger latitudinal motion, indicating a longer mean lifetime, and the associated ionospheric features indicate that the PMAFs were generated by the dayside low-latitude reconnection
Phytoplankton community changes indicated by biomarker from sediment in Prydz Bay, Antarctica
Get PDFBiomarkers including brassicasterol, dinosterol and alkenone in sediments are used as indicators to reconstruct changes to the phytoplankton community in surface and sub-aerial sediments of Prydz Bay, Antarctica. The results indicate that the biomarker records in surface and core sediment samples changed with time and space. The total content of phytoplankton biomarkers ranges from 391.0—1 470.6 ng∙g-1. The phytoplankton biomass has increased in Prydz Bay over the past 100 years. This variation may be mainly related with climate change in the region. The total biomarker contents in surface sediments from 5 stations in Prydz Bay are in the range of 215.8—1 294.3 ng∙g-1. The phytoplankton biomass in Prydz Bay is higher than that outside of the bay. This is similar to the distributions of chlorophyll a, organic carbon and biogenic silica in surface waters determined through in situ investigation. Such consistency indicates a coupling between the bottom of the ocean and biogeochemical processes in the upper water
Sustaining Arctic Observing Networks (SAON)
No full textSAON Portal is a comprehensive information gateway on the process of supporting and strengthening the development of
multinational engagement for sustained and coordinated pan-Arctic observing and data sharing systems that serve societal needs, particularly related to environmental, social,
economic and cultural issues
Comparison of the defluoridation efficiency of calcium phosphate and chitin in the exoskeleton of Antarctic krill
Get PDFCalcium (Ca), phosphorus (P), and chitin are the main components of the exoskeleton of krill. Defluoridation of a solution of sodium fluoride (NaF) using calcium phosphate (Ca3(PO4)2) and chitin as defluoridation agents was studied. Orthogonal experiments were designed to find the optimum reaction conditions for defluoridation, to obtain the maximum defluoridation efficiency and fluoride removal capacity of calcium phosphate and chitin. At the same time, a comparison of the capacity of the two defluoridation agents was made. The results suggest that calcium phosphate has a far greater capability than chitin for the removal of fluoride (F) from water under similar reaction conditions. It is also suggested that Antarctic krill is likely to adsorb fluoride via compounds such as calcium phosphate, hydroxyapatite, and other compounds of Ca and P with the general form (Ca, X)x(PO4, HPO4, Y)y(OH, Z)z, in addition to chitin
Spatial distribution of pico- and nano-phytoplankton and bacteria in the Chukchi Sea in relation to water masses
Get PDFWe evaluated the relationships between water masses and pico- and nano-phytoplankton and bacterial abundance in the Chukchi Sea. The abundance of picoplankton ranged from 0.01 × 103 cells∙mL-1 (100 m, station R05) to 2.21 × 103 cells∙mL-1 (10 m, station R05) and that of nanoplankton ranged from 0.03 × 103 cells∙mL-1 (100 m, station R07) to 2.21 × 104 cells∙mL-1 (10 m, station R05). The lowest abundance of bacteria in the whole water column (0.21 × 106 cells∙mL-1) was at 100 m at station R17, and the highest (9.61 × 106 cells∙mL-1) was at 10 m at station R09. Melting sea ice affected the physical characteristics of the Chukchi Sea by reducing salinity of the surface mixed layer, resulting in greater hydrodynamic stability of the water column. These changes were accompanied by increased bacterial abundance. The warm Pacific water brought nutrients into the Chukchi Sea, resulting in greater abundance of bacteria and nano-phytoplankton in the Chukchi Sea than in other regions of the Arctic Ocean. However, the abundance of pico-phytoplankton, which was related to chlorophyll a concentration, was higher in Anadyr water than in the other two water masses. The structures of pico- and nanoplankton communities coupled with the water masses in the Chukchi Sea can serve as indicators of the inflow of warm Pacific water into the Chukchi Sea
The Circle: Protected Areas and Beyond
No full textThe history of protected areas in the Arctic goes back more than a century, to the establishment of Afognak Island State Park in Alaska. Historically, such parks were considered to be places that would protect natural values, from species to landscapes. However, there are pressures in the Arctic that mean future conservation models must expand from the existing, relatively static park system towards more dynamic and comprehensive concepts.
In this issue of the Circle, we explore existing models for a new, expanded conservation approach and consider how they could be applied in the North -- whether by adapting a successful model from somewhere else in the globe, or growing a local approach in the Arctic.
Whatever the conservation methods chosen, it is clear that the Arctic is changing fast, and that policy makers and conservation managers must also move quickly in order to be effective at conserving the locally and globally valued – not to mention valuable - species, landscapes, and ecosystems in the region
Temperature biases in modeled polar climate and adoption of physical parameterization schemes
Get PDFAn annual cycle of atmospheric variations for 1989 in the Arctic has been simulated with the Weather Research and Forecasting (WRF) model. A severe cold bias was found around a cold center in surface air temperature over the Arctic Ocean, compared with results from ERA-Interim reanalysis. Four successive numerical experiments have been carried out to find out the reasons for this. The results show that the sea ice albedo scheme has the biggest influence in summer, and the effect of the cloud microphysics scheme is significant in both summer and winter. The effect of phase transition between ice and water has the biggest influence over the region near the sea ice edge in summer, and contributes little to improvement of the severe cold bias. The original crude albedo parameterization in the surface process scheme is the main reason for the large simulated cold bias of the cold center in summer. With a different land surface scheme than in the control run, cold biases of simulated surface air temperature over the Arctic Ocean are greatly reduced, by as much as 10 K, implying that the land surface scheme is critical for polar climate simulation
Framework Agreement between the Government of Iceland and the Government of the People's Republic of China on Arctic Cooperation
Get PDFThe Government of the People's Republic of China and the Government of Iceland (hereinafter referred to as "the Parties"), Reaffirming the friendly bilateral relations between the countries, Recognizing that cooperation between Arctic States and non-Arctic States can promote studies of trans-regional Arctic issues, Desiring to cooperate on Arctic issues, on the basis of mutual respect, reciprocity and mutual benefit, with the aim to further strengthen their friendly bilateral relations