极地研究

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Characteristics and variations of picophytoplankton community in the Arctic Ocean

MA Yuxin, HE Jianfeng, ZHANG Fang, LIN Ling, YANG Haizhen & CAI Minghong

2012, 23 (3-English): 133-140. DOI: 10.3724/SP.J.1085.2012.00133

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Picophytoplankton is responsible for much of the carbon fixation process and plays an important role in the active microbial food webs in the Arctic Ocean. Climate change is evident in the Arctic Ocean in recent years, picophytoplankton, as the most vulnerable part of high-latitude pelagic ecosystems, is receiving more attention. This summary mainly reviews the researches on picophytoplankton characteristics, including their abundance, biomass, spatial distribution, seasonal variation, community structure and the factors influencing their growth. In addition, the impact of climate change on picophytoplankton community and the prospect of this study field are also generalized.

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Factors influencing small-scale distribution of 10 macrolichens in King George Island, Western Antarctica

LIU Huajie, WU Qingfeng & FANG Shibo

2012, 23 (3-English): 141-148. DOI: 10.3724/SP.J.1085.2012.00141

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Lichens are among the main primary colonists in most terrestrial ecosystems of Antarctica, where the effects of environmental factors on spatial distribution of lichens are essential to understand the functioning of Antarctic terrestrial ecosystems. We measured abundance of 10 frequently observed macrolichens and environmental factors at a small scale (20 × 20 cm), in the ice-free areas of Fildes Peninsula and Ardley Island, King George Island, West Antarctica, and assessed the effects of environmental factors on the local distribution of lichens. Canonical correspondence analyses (CCA) show that 8 out of 15 environmental factors, belonging to 4 sets of variables, are important in spatial distribution of the 10 lichens. Variation partitioning analyses show that most of the variation in distribution of the 10 lichens is described by the spatial heterogeneity of substrate, bird influence and microclimate and topography, whereas human impact has no significant effects.

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Comparison of the defluoridation efficiency of calcium phosphate and chitin in the exoskeleton of Antarctic krill

WANG Zhangmin & YIN Xuebin

2012, 23 (3-English): 149-154. DOI: 10.3724/SP.J.1085.2012.00149

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Calcium (Ca), phosphorus (P), and chitin are the main components of krill crust. Defluorination of a simulated solution of Sodium Fluoride (NaF) using calcium phosphate [Ca3(PO4)2] and chitin as defluorine agents was studied. Some orthogonal experiments were designed to find the best reaction conditions for defluorination, so as to obtain the maximum defluorine efficiency and fluoride removal capacity of calcium phosphate and chitin, and at the same time, a comparison about the capacity of these two defluorine agents was made. The results suggest that calcium phosphate, compared with chitin, under similar reaction conditions, has a far more capability to remove fluoride (F) from water. It is also suggested that, Antarctic krill is also likely to enrich fluoride by these kinds of substances such as calcium phosphate, hydroxyapatite, and other compounds of Ca and P generalized as form of (Ca,X)x(PO4,HPO4,Y)y(OH,Z)z, in addition to the presence of chitin.

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Eco-environmental spatial characteristics of Fildes Peninsula based on TuPu models

PANG Xiaoping & LI Yanhong

2012, 23 (3-English): 155-162. DOI: 10.3724/SP.J.1085.2012.00155

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This study applies a TuPu analysis to investigate ecological and environmental aspects of an Antarctic ice-free area, using Fildes Peninsula as an example. The TuPu unit was determined using a vector-grid mixed data model. Information from the eco-environment elements was effectively extracted, and was generalized into different classes by means of data mining technology. A series of single-factor thematic information TuPu models, such as topography, soil, animal and vegetation, and human activities for Fildes Peninsula were built in this study. The topography TuPu model contained information on elevation and slope. The soil TuPu model involved soil development stages and soil thickness information. The animal and vegetation TuPu model contained the distribution of animals, plant types, lichen cover and lichen height. The human activities TuPu model included population density and human disturbance index information. The landscape comprehensive information TuPu model of Fildes Peninsula also was established, and contains twenty-nine landscape units and twelve types of combined environments. The study quantitatively revealed the spatial morphology and correlation of the regional eco-environment based on the analysis of these TuPu models. From these models, we can draw the conclusion that there is a regular differentiation of eco-environment from the coastal bands to the central hills in Fildes Peninsula, and that the eco-environment condition of the eastern coasts is different from that of the western coasts. The eco-environmental spatial variation also differs greatly from north to south. Based on analysis of spatial correlation, the vegetation in Fildes Peninsula has the greatest correlation with human activity, and has a certain correlation with topography and soil. This research may provide a new technical approach and scientific basis for the in-depth study of Antarctic eco-environments.

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Vertical structure of low-level atmosphere over the southeast Indian Ocean fronts

FENG Lin, LIU Lin, GAO Libao & YU Weidong

2012, 23 (3-English): 163-169. DOI: 10.3724/SP.J.1085.2012.00163

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GPS radiosondes were launched to detect the vertical structure of the atmosphere over the southeast Indian Ocean fronts region during the 25th Chinese Antarctic Expedition. Characteristic regarding the vertical profiles of the atmospheric variable along the cruise are studied. The in-situ observations reveal that the vertical distributions of the low level wind field and the air temperature on both sides of the subantarctic front are quite different. Stronger (weaker) vertical gradient appears on the cold (warm) side, which demonstrates that the mid-latitude ocean-atmosphere interaction is also active in the southeast Indian Ocean fronts region. A low-level jet is observed over the subantarctic front with the speed up to 14m/s. For the Antarctic polar front, the low level wind speed near sea surface is larger than the aloft one, which is distinct to the situation of the subantarctic front. Compared to the widely used reanalysis and satellite remote sensing datasets, it is found that ERA Interim dataset is more consistent with the in-situ observation than NCEP/NCAR Reanalysis 1, and AIRS datasets has the quite good consistence with the observation over the southeast Indian Ocean region.

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Cognitive effects of long-term residence in the Antarctic environment

YAN Gonggu, WU Songdi, WANG Tianle, ZHANG Xuemin & SAKLOFSKE Donald H

2012, 23 (3-English): 170-175. DOI: 10.3724/SP.J.1085.2012.00170

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The purpose of this study was to examine whether prolonged residence in the Antarctica had a significant impact on cognitive performance. Participants were members of the 24th and 25th Chinese Antarctic expedition teams. Cognitive performances were measured by tests designed to evaluate short-term recognition, memory searching and spatial cognition, and were measured at four intervals in January, March, April, and June 2010 respectively. With age controlled as a covariate, data were analyzed using repeated-measure ANOVA. The results showed that subjects’ short-term memory and recognition ability remained stable, while 82% of the team members improved their scores on the spatial cognitive ability test. These findings have importance for furthering our understanding of cognitive functioning in extreme environments.

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Russian researchers reach subglacial Lake Vostok in Antarctica

TALALAY Pavel

2012, 23 (3-English): 176-180. DOI: 10.3724/SP.J.1085.2012.00176

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Opening a new scientific frontier lying under the Antarctic ice, Russian researchers have drilled down and finally reached the surface of the gigantic freshwater lake, Lake Vostok. The mission chief likened the achievement to placing a man on the moon. Drilling in the area of the lake began 22 years ago in 1990, but progressed slowly as a result of funding shortages, equipment breakdowns, difficulties of drilling in the “warm” ice, and environmental concerns. In 1996, six years after drilling was started, a group of Russian and British scientists discovered the lake believed to be one of the largest fresh water reservoirs on the planet. This lake is among the last unexplored places on Earth. Sealed from the Earth’s atmosphere for millions of years, it may provide vital information about microbial evolution, the past climate of the Earth, and the formation of the Antarctic ice sheet. Russian experts waited several years for international approval of their drilling technology before proceeding. As anticipated, lake water under pressure rushed up the borehole, pushing the drilling fluid up and away, then froze, forming a protective plug that prevented contamination of the lake. In December of the next Antarctic season, 2012—2013, researchers plan to re-drill the frozen sample of subglacial water for analysis.

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Development of the geodetic coordinate system in Antarctica

ZHANG Shengkai & E Dongchen

2012, 23 (3-English): 181-186. DOI: 10.3724/SP.J.1085.2012.00181

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Defining 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.

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