The investigation on sea-ice biology in combination with physics, chemistry and ecology was carried out in the northwestern Weddell Sea, Antarctica, during the cruise ANT/XX Ⅲ-7 on board POLARSTERN in the austral winter (August-October) in 2006. The distribution of chlorophyll a was measured and related to sea ice texture. The mean concentrations of chlorophyll a in the sea ice varied considerably with ice texture. The concentration of chlorophyll a per core ranged from 2.10-84.40 μg/dm³ with a mean of 16.56 μg/dm³. And the value of R (chlorophyll a/gross chlorophyll) ranged from 0.79-0.83. These high winter chlorophyll values indicate that primary production is considerable and confirms that there is significant primary production in Antarctic sea ice during winter. Thus this constitutes a major proportion of southern ocean primary production and carbon flux before the sea ice retreats.

The diversity of modular polyketide synthase (PKS) genes in sediments of Ardley Island in Antarctica, was studied by restriction fragment length polymorphism (RFLP) analysis. Phylogenetic analysis of 14 amino acid (AA) sequences indicates that the identified ketosynthase (KS) domains were clustered with those from diverse bacterial groups, including Cyanobacteria, γ-Proteobacteria, Actinobacteria, Firmicutes, and some unidentified microorganisms from marine sponge, bryozoan and other environmental samples. The obtained KS domains showed 43%-81% similarity at the AA level to reference sequences in GenBank. Six identified KS domains showed diverse sequences of the motif (VQTACSTS) that was used to identify the hybrid PKS/nonribosomal peptide synthetase (NRPS) enzyme complex, and formed a new branch. These results reveal a high diversity and novelty of PKS genes in antarctic sediments.

To explore the spatial pattern of macrobenthic communities and their response to environmental factors in the Prydz Bay, samples were collected using a 0.25-m² box corer at 10 stations from November 2012 to April 2013. A total of 50 species of macrobenthos belonging to 8 phyla and 33 families were identified, of which polychaetes (e.g., Maldane sarsi) and sponges (e.g., Halichondria sp. and Leucosolenia sp.) were the most prominent groups. The macrobenthos in study area were categorized into five functional groups based on the feeding type, and the detritivorous group represented by polychaetes showed the highest average abundance, while the planktophagous group represented by sponges showed the highest average biomass. Macrobenthos abundance (0–592 ind./m²) and biomass (0–1 155.5 g/m²) in the Prydz Bay were relatively lower than those of other Antarctic shelf soft-bottom waters, although the compositions of the dominant species and functional feeding groups were similar. The results of the Spearman rank correlation analysis indicated that the average biomass of the macrobenthos and the biomass of the planktophagous group in the study area were negatively correlated with the water depth, sediment grain size and silt percentage. However, these variables were clearly not strong determinants of macrobenthos assemblage structure. Many factors not measured in the study, e.g., sediment organic matter and iceberg interference, have probably influenced the spatial distribution of macrobenthic community structure in the Prydz Bay.

本研究将稳定同位素（¹⁵N）与放射性核素（²²⁶Ra）示踪相结合，探讨了2006年夏季南极普里兹湾融冰过程对氮吸收的调控作用。硝酸盐及铵盐的比吸收速率均与浓度呈正相关关系，表明底物浓度效应的存在。开阔洋区具有较高的f比值，而在埃默里冰架附近f比值低得多。f比值与冰融水份额之间存在负相关关系，暗示融冰过程在调控水体氮吸收方面起着重要作用。融冰改变了当地上层水体的层化条件，显著地影响南大洋的生物泵效率及对大气二氧化碳的吸收。本研究为南大洋上层水体碳、氮动力学的调控机制提供了新的认识，且有助于对历史记录的解读及对未来气候变化的预测。

During the 16th Chinese National Antarctic Research Expedition(CHINARE)(from November 1999 to April 2000) seawater samples were collected for(DOC) determination in the Prydz Bay and its nearby sea areas.DOC concentrations were determined by high temperature catalytic oxidation(HTCO) method.The results shows that DOC concentrations in the upper water column(0~100 m) range from 14.3 to 181.1 μmol/dm³,with averaging 52.5 μ mol/dm³(n=55).These values are slightly higher than those reported for the Ross Sea,the Pacific Ocean and others.Profiles of DOC concentration in the study areas show a decreasing concentration with increasing depth in the upper 100 m,which is related to biological activities in the water column.DOC concentrations below 100 m are relatively constant with a mean of 40.4 μmol/dm³.These DOC are unactive for physical and biological activities and are called refractory DOC.Concentration of the refractory DOC in the study area is consistent with the previous reported values for the Southern Ocean,which is about 41 μmol/dm³.Based on the difference between the measured DOC concentration and the refractory concentration,the excess DOC concentration in the upper column can be calculated at every station.The excess DOC shows a spatial variability with a higher excess in the north of 64°S and little excess in the south of 64°S.In conclusion,DOC concentrations in the Prydz Bay and its nearby sea areas are consistent with the previous reported values in the Southern Ocean,which show a low DOC concentration with respect to the other oceans.Distribution of surface DOC concentrations in the study areas shows an increase from the southwestern to the northeastern,which is ascribed to the northern spread of continental shelf water from the Prydz Bay in summer.Contents of DOC and their distribution in the Prydz Bay and its nearby sea areas are mainly controlled by physical and biological processes.

The antarctic sea ice was investigated upon five occasions between January 4 and February 15, 2003. The investigations included:(1)estimation of sea ice distribution by ship-based observations between the middle Weddell Sea and the Prydz Bay; (2) estimation of sea ice distribution by aerial photography in the Prydz Bay; (3) direct measurements of fast ice thickness and snow cover, as well as ice core sampling in Nella Fjord; (4) estimation of melting sea ice distribution near the Zhongshan Station; and (5) observation of sea ice early freeze near the Zhongshan Station. On average, sea ice covered 14.4% of the study area. The highest sea ice concentration (80%)was observed in the Weddell Sea. First-year ice was dominant (99.7%~99.8%). Sea ice distributions in the Prydz Bay were more variable due to complex inshore topography, proximity of the Larsemann Hills, and/or grounded icebergs. The average thickness of landfast ice in Nella Fjord was 169.5 cm. Wind-blown snow redistribution plays an important role in affecting the ice thickness in Nella Fjord. Preliminary freezing of sea ice near the Zhongshan Station follows the first two phases of the pancake cycle.

Ecological research has been made for quite a long period in some marine-derived saline lakes in the Vestfold Hills,Antarctica.The results show distinct succession of zooplankton community in those lakes.The change in community structure of zooplankton is related directly to environmental evolution in nature and the variation of lake conditions,such as physical and chemical factors as well.In the Burton Lake,there is a rather stable annual fluctuation in both temperature and salinity,and the community has probably been in the stage of climax succession.The Fletcher Lake is still undergoing a process by unregular tide flood from nearby bay,so that zooplankton community has been changing due to variance in temperature and salinity.

During the expedition from Dec. 1981 to Feb. 1982, Dry Valley, Victoria and Ross Island Beach in Antarctica were visited. From ten stations samples of water, soil, snows and seawater were collected, from which heterotrophic microbes (including bacteria, yeast and fungi) were isolated and identified. Results show that there are ten genera of bacteria, nine genera of yeast and nine genera of fungi. Most of the strains grow at the temperatures of 20℃ and 5℃, while a few grow only below 5℃. More bacterial genera were isolated from the beach and nearby lakes than those from the inland Dry Valley, indicating the relations between the strain composition and geographical location and environmental conditions of the polar zone.

A high resolution one-dimensional thermodynamic snow and ice (HIGHTSI) model was used to model the annual cycle of landfast ice mass and heat balance near Zhongshan Station, East Antarctica. The model was forced and initialized by meteorological and sea ice in situ observations from April 2015 to April 2016. HIGHTSI produced a reasonable snow and ice evolution in the validation experiments, with a negligible mean ice thickness bias of (0.003±0.06) m compared to in situ observations. To further examine the impact of different snow conditions on annual evolution of first-year ice (FYI), four sensitivity experiments with different precipitation schemes (0, half, normal, and double) were performed. The results showed that compared to the snow-free case, the insulation effect of snow cover decreased bottom freezing in the winter, leading to 15%–26% reduction of maximum ice thickness. Thick snow cover caused negative freeboard and flooding, and then snow ice formation, which contributed 12%–49% to the maximum ice thickness. In early summer, snow cover delayed the onset of ice melting for about one month, while the melting of snow cover led to the formation of superimposed ice, accounting for 5%–10% of the ice thickness. Internal ice melting was a significant contributor in summer whether snow cover existed or not, accounting for 35%–56% of the total summer ice loss. The multi-year ice (MYI) simulations suggested that when snow-covered ice persisted from FYI to the 10th MYI, winter congelation ice percentage decreased from 80% to 44% (snow ice and superimposed ice increased), while the contribution of internal ice melting in the summer decreased from 45% to 5% (bottom ice melting dominated).

2006年冬末春初,在德国POLARSTERN科学考察船执行南极威德尔海西北海域考察期间,调查了考察区海冰物理和海洋生物。本文观测了航线上钻取的27支海冰冰芯的组构和71个冰晶体薄片;分析得到393组冰温数据;348组盐度、密度数据和311组叶绿素a和脱镁叶绿素含量数据;通过302组冰内相同深度孔隙率和叶绿素a含量数据分析,发现海冰物理参数影响冰内叶绿素a含量的新证据;利用收集的雪、冰厚度数据以及环境容量制约生态平衡的规律,建立了雪、冰厚度对冰底叶绿素繁荣的影响以及;确立了南极粒状冰和柱状冰内叶绿素a上限含量同卤水体积的关系。从而表达了冰晶体对卤水排泄的效应和冰物理性质对南极春季冰底和冰-水界面叶绿素a增长的贡献。此外,还得出海冰物理性质影响冰藻,并且是南极冰区水体浮游植物繁荣的关键控制因素。