对西南南乔治王岛西湖沉积物XH1柱样进行了210Pb测年,建立起百余年(1885—2006年)沉积地层序列.定量分析了该柱样中的正构烷烃、脂肪酸和甾醇等类脂生物标志物,综合南南了其分子组合特征和大尺度气候事件[厄尔尼诺-南方涛动(ENSO)和南半球环状模(SAM)]指标,探讨了湖泊沉积有机质来源、沉积环境和早期成岩作用及其与生态环境变化的关系.结果表明,正构烷烃的主峰碳(nC23)、脂肪酸的后主峰碳(C24:0)、较高的C29甾醇含量和较低的∑C21-/∑C22+比值均显示,苔藓、地衣等低等陆生植物是西湖沉积物中有机质的主要来源,而水生动植物及微生物的贡献相对较少.脂肪酸C18:2/C18:0比值表明,在年代际时间尺度上,与ENSO相比,SAM对南南半岛生态系统可能更具影响力,且对湖泊水生动植物的影响比陆生植物更为明显.内源输入的甾醇指标ACI显示,西风变弱、南南半岛变暖时,沉积物中水生生物贡献的有机质减少.整体而言,过去的100多年中,西湖呈弱氧化的沉积环境,早期成岩作用较弱,且气候事件对湖泊沉积环境影响不大.

The settling of particulate carbon in seawater is a key component of the ocean carbon cycle. We deployed a set of sediment trap in the polynya of Prydz Bay from December 2010 to December 2011 to investigate the seasonal variations in particle fluxes. There was a clear seasonal variation in the particle fluxes, with maximum and minimum fluxes recorded during the summer and winter, respectively. The average total flux over the sampling period was 193.58 mg m −2 d −1 , and the average fluxes of organic carbon (C org ), inorganic carbon (C inorg ), and biogenic silica (Si bio ) were 721.78, 28.67, and 2382.80 μmol m −2 d −1 , respectively. Si bio was the main contributor to the total mass flux, and strongly correlated with C org . The high Si bio /C org molar ratios (>1) suggest that C org was transported to deep sea in association with Si bio . By comparing remote sensing data of sea ice and chlorophyll in the upper water column, we found that the dynamics of carbon fluxes were closely related to changes in sea ice. Algae in sea ice may have a key role in biological pump processes in early summer. Apart from the ice algae bloom period, variations in carbon fluxes generally corresponded with phytoplankton blooms in the upper water. The ballast effect controlled the particle settling velocity and the efficiency of the biological pump. Sea ice rafts initiated the first particle export event and enhanced the particle settling efficiency during melting period. As diatoms might become less dominant in the ice-free area, sea ice loss may cause the efficiency of the biological pump efficiency to decrease over the long term.

To understand the biological pump of the Antarctic Ocean,two sets of time-series sediment trap was deployed and recovered in the polynya of the Prydz Bay during the 26th and 31 st Chinese Antarctic scientific expeditions in the austral summer of 2009～2010 and 2014～2015.The particle fluxes were analyzed.The results showed that the summer fluxes of particulate organic carbon (POC) were 4088.13 and 508.99μmol/(m2·d) for the year of 2009～2010 and 2014～2015,respectively,while biogenic silica (BSi) were 7358.91 and 2034.63 μmol/(m2·d),respectively.The biogenic opal contributed more than 70％ of total mass flux in two years,which indicated diatoms should be the dominated species in the column and the main carriers of sinking POC during austral summer.The POC flux in 2014～2015 was only 12.5％ of that in 2009～2010.It was mainly due to the lack of ballast matters that prevented the rapid settling of organic matter in the upper layer,resulting in more degrading organic matter in the upper water column caused by heterotrophic microorganisms.Compared with other Antarctic marginal seas where the blooms were not dominated by diatoms,the Prydz Bay polynya is characterized of higher sinking fluxes and efficiency.Estimated by the Martin curve,the 100m POC flux in summer in Prydz Bay averages 8.67％ of the net primary productivity.It mainly owed to the diatom-dominated plankton community in the Prydz Bay polynya,therefore the plankton community in polar oceans should attract more attention when predicting the variation of biological pump.

A part of the heavy metals in estuary and coastal zone occurs naturally in the environment; the other part is due to human activity; so the directly measured concentration of heavy metal does not automatically indicate anthropogenic enrichment. Fe2O3 was used in this study as conservative tracer to distinguish natural components from anthropogenic components of heavy metal sediment concentration in the Zhujiang estuary. Compared with clay and Al2O3, Fe2O3 is more suitable as reference element. The final results showed that two zones in the Zhujiang estuary were seriously contaminated by heavy metals. One nearby the Humen mouth; the other around the west coast of the estuary. The horizontal distribution of heavy metals indicates that Zn, Ni and Cu have wider contaminating areas than TiO2, V and Cr in the estuary.

Nutrient data collected in Prydz Bay during the CHINARE 25/27/29 cruises were analyzed to study the distribution pattern of nutrient concentrations. The consumption, absorption ratio, and structure of nutrients (NNU, NPU, and NSiU) in summer were evaluated based on the existence of theTmin layer. The results showed that the spatial distributions of nutrient concentrations in the surface waters of Prydz Bay had obvi-ous regional characteristics. The highest, intermediate, and lowest concentrations of nutrients were observed in the open sea, continental shelf, and marginal ice shelf areas, respectively. Consumption of nutrients in inner areas of Prydz Bay was higher than outer areas partly because of the influence of the phytoplankton bloom in austral summer; a period in which nutrients are absorbed by phytoplankton for photosynthesis. The NSiU/NNU ratios showed distribution patterns similar to nutrient concentrations but opposite to Chla con-centration. It is speculated that this difference is mainly due to the higher supply of iron in the continental shelf region and inner Prydz Bay area comparted with the open sea. Investigation of the structure and changes of nutrient concentrations in Prydz Bay can help us better understand the biogenic element cycle processes in the Southern Ocean and provide a basis for predicting the evolution of phytoplankton structure in the Southern Ocean.

It’s reported that the composition of phytoplankton indicator species and correlation between them and the nutrient contents in the Antarctic Bay Antarctic water South Atlantic South Indian Ocean. The results showed that there was significant negative correlation between phytoplankton and nutrients investigation. Distribution of phytoplankton cell abundance was Antarctic Bay (18.6×104cells/dm3) > Antarctic water (8.3×104cells/dm3) > South Atlantic (4.5×104 cells/dm3) > South Indian Ocean (3.1×104cells/dm3); Nutrient (N, P, Si) content in the South Atlantic waters was highest in the investigation areas. Phytoplankton indicator species were mainly diatoms components of Chaetoceros dichaeta, Corethron criophilum, Fragilariopsis curta, Fragilariopsis kerguelensis, Nitzschia barkleyi, Proboscia alata, Rhizosolenia styliformis, Trichotoxon reinboldii, Thalassiosira antarctica, etc.; other dinoflagellates components of Gymnodinium gracile, Gymnodinium baccatum, Gyrodinium lachryma, Protoperidinium archiovatum, Protoperidinium obovatum in the Southern Ocean. Keywords-phytoplankton; indicator species; nutrient contents; the Southern Ocean.

利用电感耦合等离子体质谱仪测定了中国南极科考21～27航次期间获取的普里兹湾表层沉积物中Cu、Pb、Zn、Cd、Cr、Co、Al、Fe、Mn的含量,分析了普里兹湾微量元素的分布特征,结合沉积物粒度分布、生物硅含量,并利用富集系数和主成分分析的方法,探讨了微量元素的物源指示意义.研究结果表明:普里兹湾沉积物中的微量元素含量与南大洋其他海域具有很好的可比性.Cu、Zn、Cr、Co、Fe、Mn含量在陆坡深海区明显高于冰架边缘区和陆架区;Al、Pb含量在冰架边缘区较高;而Cd含量在陆架区相对较高.人类活动对普里兹湾沉积物中的微量元素没有明显的影响,南极大陆岩石风化产物和海洋生物源性沉降是其主要来源.冰架边缘区及陆架破折处P2-9站位的微量元素主要为岩源性输入.陆架区、陆坡深海区的微量元素Cu、Zn、Cr、Co、Fe、Mn明显受到生源性物质输入的影响.而普里兹湾沉积物中Cd则主要来源于硅藻的吸收利用及硅质软泥的富集.

The Zn/Si records of diatom opal from Prydz Bay were investigated. The results show that the Zn/Si ratios range from 8 to 53μmolmol−1. The ratio from the continental slope is higher than those from the shelf. The difference in Zn/Si records could be attributed to the change of bioavailable Zn via the upwelling of Zn2+-rich deep water or the influence of oceanic water on the slope. However, phytoplankton productivity influences Zn/Si records on the continental shelf. Increased productivity leads to elevated Zn-pumping, and eventually to higher Zn/Si ratio in diatom opal. In this case, it is suggested that Zn/Si proxy could be a signal of marine productivity on the continental shelf of Prydz Bay. The down core profile of Zn/Si records shows an increase in marine productivity over the last century.

Particulate fluxes of trace elements (Al, Fe, Mn, Cu, Pb, Zn, Cd and Co) in the polynya area of Prydz Bay were measured using time series sediment trap lasting from December 16th 2010 to December 16th 2011. The comparison of annual fluxes from different regions, the seasonality and sources of trace element, and their association with organic matters were investigated. The fluxes of Cu, Zn and Cd in the polynya area of Prydz Bay are dominated by marine biogenic sources. Their similar seasonality with the export of biological materials (biogenic silica, organic carbon, and calcite carbonate) is strongly related to the ice coverage and biological production. Mineral debris derived from Antarctic continent is suggested to account for the particulate fluxes of Al, Fe, Mn, Pb and Co in the polynya. Their seasonal variations are most likely controlled by ice melting and freezing process. Furthermore, their fluxes are also influenced by scavenging onto biogenic material for Pb and uptake by phytoplankton for Co. The excess fluxes of Cu, Zn and Cd have good relationship with organic carbon export. The coupling patterns are mainly regulated by source composition of trace elements and non-lithogenic input from atmospheric deposition or upwelling, and partly influenced by biological uptake process.

利用中国南极科学考察期间获得的颗粒物样品,对南大洋普里兹湾海域水体中生物硅的含量分布及年际变化情况进行了分析.研究结果显示:在2013年夏季普里兹湾表层水体中生物硅含量在0.38-8.62μmol/dm3之间变化,平均为1.55±1.86μmol/dm3.生物硅在67°S以南湾内区域表层水体中的含量明显高于67°S以北的湾外区域,最大值出现在普里兹湾陆架区,生物因子是表层水体生物硅含量分布的主控因子.根据不同年份即25、26、27、28、29次南极科学考察期间获取的数据研究显示,普里兹湾表层水体中生物硅含量存在明显的年际差异.历史数据分析结果表明,气候事件对普里兹湾海冰变化有明显的影响,因而对相应年份该海域浮游植物数量和种群结构也会产生一定的影响,从而导致表层水体中生物硅含量的年际差异.

A number of major and trace elements including C, N, Ca, and Al were measured in 20 surface sediment samples collected from Prydz Bay, Antarctica, during the CHINARE 18—27 cruises.The distributions of these ele-ments and their characteristics of association were used to explore the sedimentary environment and material sources within the study area.The results showed that the values of most of the elements in the surface sediments changed over a wide range.Furthermore, the elemental distribution, correlation, and clustering features presented two pat-terns.One represented by OC, TN, and S that indicated a source of marine organisms, and the other represented by K, Ti, and Rb that indicated a source of terrigenous clastics.The results also suggested that sedimentation at the center of Prydz Bay and the southeastern area was controlled by biological production, whereas sedimentation near the Fram Bank and continental shelf in front of the Amery Shelf, contained a large number of ice-rafted clasts.

We used the normative calculation and sequential extraction methods to determine the concentration of biogenic barium, and compared the results of the two methods .The concentration of biogenic barium calculated using the normative calculation method was much higher than the result from sequential extraction , which suggested that bari-um associated with Mn and Fe oxides contributed considerably to total barium .The concentration of biogenic barium based on sequential extraction ranged from 104 to 445 μg · g-1 , with an average content of 227 μg · g -1 .The highest levels of biogenic barium were recorded in the center of the bay , where the seawater is more stable , and lower values were found near the shore and over the ice shelf .Biogenic barium concentration showed a significant linear correlation with BSi and OC , and was also closely correlated to chlorophyll a concentration .This finding in-dicates that primary productivity of phytoplankton in the surface water column is the main environmental factor regu -lating the concentration and distribution of biogenic barium in Prydz Bay .

利用中国多次南极科学考察获得的沉积物样品,对普里兹湾沉积物中有机碳(OC)、总氮(TN)的含量和分布以及OC/TN进行了分析.结果表明:普里兹湾表层沉积物中OC和TN的含量变化范围分别为0.14％～ 1.20％和0.02％～0.20％,平均值分别为0.63％和0.11％.OC/TN的变化范围为5.5～8.2,平均值为6.8.OC和TN含量呈现明显的正相关性,表明有机质来源相同,比值接近6.6,说明有机质主要为海洋生源沉积.两者平面分布趋势非常一致,且与沉积物中泥质含量呈显著正相关,湾内73°E以西区域OC和TN含量较低,而以东区域含量较高,这是上层水体生产过程和冰川携带陆源砂等因素共同作用的结果.垂直分布上,OC和TN含量总体上表层高于深层,OC含量随深度增加逐渐降低,达到一定深度后趋于稳定.较高的沉积速率加速OC的埋藏,5根柱样中OC的埋藏率为39％～91％,平均为66％,表明普里兹湾是重要的碳汇区.

Multiple biomarkers has been analyzed by gas chromatography and gas chromatography-mass spectrum on sur-face sediments collected from 5 stations in Prydz Bay,East Antarctica,and its implication on ecology and environ-ment has been discussed.The results showed that the concentration of total lipids was highest in the center area of Prydz Bay (1 193 μg·g-1 ),follow by Amery Ice Shelf area (572 μg·g-1 ),and lowest in slope area (341 μg ·g-1 ).It was significantly positive correlated with sedimentary organic carbon,total neutral monosaccharides,bi-ogenic silica,brassicasterol,and chlorophyll a concentrations in surface sea water (p<0.1 ),and indicated that organic matter preserved in surface sediment was mainly from marine phytoplankton.The significantly negative cor-relation of relative concentrations between C27 and C28 steranes showed the food chain between Euphausia crystal-lorophias and diatoms.The relative high ratio of saturated hydrocarbons:arenes (>2.5),low ratios of Pr/C17(<0.5)and Pr/Ph (<2)inferred the sedimentary organic matter was largely contributed by diatoms.Meanwhile,the double peak of saturated hydrocarbons (C17 or C18,C29)and relative high concentration of C29 steranes (35.79%) showed terrestrial vascular plants input,and it was higher in the center area of Prydz Bay (CPI=1 .60,Pr/Ph=0.69)than the slope area and Amery Ice Shelf area (CPI=1.01,Pr/Ph=0.39).The ratio of C18:2/C18:0 for fatty acids was higher in sediment collected from the center area of Prydz Bay and Amery Ice Shelf area (0.78)than that from slope area of Prydz Bay (0.23)and lower latitude regions (<0.1),and indicated that during austral sum-mer,the surface sea temperature was higher in slope area of Prydz Bay than center area of Prydz Bay and Amery Ice Shelf area.

The historical data of phytoplankton and chlorophyll a (Chl a) (1990–2002) obtained during the Chinese National Antarctic Research Expedition (CHINARE) in the Prydz Bay have been integrated. The results showed that the temperature, salinity, nutrients, and oxygen of seawater changed when El Niño/La Niña occurred. The variation of biological communities reflected the response of ecosystem to environmental changes. During El Niño period, Chl a concentration and phytoplankton community structure changed significantly, and the relative proportion of diatoms increased while dinoflagellates decreased. During La Niña period, the proportion of diatoms decreased, but the golden-brown algae and blue-green algae increased significantly. The variation of phytoplankton population directly affected the biodiversity of the bay, which were also quite sensitive to the marine environment changes. Meanwhile, the satellite remote sensing data of 2002–2011 (December–March) have been used to study the temporal connection change of Chl a and phytoplankton in the Prydz Bay. We found that there were significant differences in the monthly variation characteristics of satellite remote sensing Chl a and sea surface temperature (SST), which had some links with sea ice melting and El Niño/La Niña events. We found that the start time of bloom advanced, lagged or synchronized with the changes of the SST, and we also found the occurrence time of phytoplankton bloom corresponded with the sea ice melting inner bay. To some extent, this study will help us understand the relationships between ENSO events and the phytoplankton bloom in the Southern Ocean.

The study provides one of the first lines of evidence showing linkages between Antarctic phytoplankton abundance and composition in response to ENSO, based on historical reconstruction of sediment biomarkers. In addition to sediment biomarkers, field measured and remote sensing data of phytoplankton abundance were also recorded from Prydz Bay, Eastern Antarctica. Community structure of field measured phytoplankton showed significant El Niño/La Niña-related succession during 1990 to 2002. In general, the number of algae species decreased during El Niño and La Niña years compared to normal years. Austral summer monthly variation of remotely sensed chlorophyll-a (Chl-a), particulate organic carbon (POC), and sea surface temperature (SST) indicated that ENSO impacted the timing of phytoplankton blooms during 2007 to 2011. Phytoplankton blooms (indicated by Chl-a and POC) preceded the increases in SST during El Niño years, and lagged behind the SST increases during La Niña years. Stratigraphic record of marine sedimentary lipid (brassicasterol, dinosterol and alkenones) biomarkers inferred that the proportions of different algae (diatoms, dinoflagellates and haptophytes) changed significantly between El Niño and La Niña events. The relative proportion of diatoms increased, with that of dinoflagellates being decreased during El Niño years, while it was reversed during La Niña years.

In this study, we have determined the contents and distribution of zinc and cadmium in the surface sediments from Prydz Bay, East Antarctica.The main sources of the trace elements and their geographic heterogeneity, and the relation between Zn and Cd, are discussed based on the cluster analysis, principle component analysis and considerations of biogenic and lithogenic inputs.The results show that the contents of trace metals range from 34.6 to 96.6 mg kg (1 for Zn, and from 0.254 to 0.441 mg kg (1 for Cd.Calculations of the enrichment factor indicated no significant anthropogenic impact.Biogenic and lithogenic inputs are the main sources of trace metals.They are almost equal for Zn and Cd at the Amery Ice Shelf edge, while the continental shelf and deep ocean are dominated by biogenic inputs.The contribution of biogenic inputs is much higher for Zn than for Cd at the deep ocean.Calculations of biogenic trace metals revealed different relationships between biogenic Zn and biogenic Cd, which reflect the biological uptake by phytoplankton in the water column.

利用中国第21—27次南极考察期间获得的沉积物样品,对南大洋普里兹湾沉积物中锗（Ge）的含量以及分布特征进行初步研究。结果表明:普里兹湾表层沉积物中总Ge（Getotal）的含量在1.14×10-6—2.35×10-6之间变化,平均含量为1.71×10-6,最高值出现在湾外深海区P3-9站位,最低值出现在湾内冰架边缘附近的P4-13站位。在研究海域的表层沉积物中,生源Ge（Gebio）占Getotal的百分含量在16%—68%之间变化,Gebio与Getotal分布变化趋势总体上相近,以67°S为界均呈现湾外高于湾内的趋势,在柱状沉积物中Ge的垂向分布呈现表层高于底层趋势。在普里兹湾湾内非冰间湖区域的表层沉积物中Gebio与生物硅（BSiO2）呈现一定的正相关,在P3-16站位柱状沉积物中Gebio与BSiO2垂向分布相似。

Concentrations of biogenic barium were investigated in surface sediments of Prydz Bay,Antarctica,during the 21st and27th CHINARE cruises.Factors controlling the observed distribution are explored.Biogenic barium concentrations obtained from a sequential extraction procedure are compared with total concentrations obtained from the normative calculation based on a total digestion,and differences in the results are examined.Concentrations of biogenic barium,calculated by the normative calculation,were much higher than the concentrations obtained through sequential extraction;this discrepancy is the result of the occurrence of barium associated with Mn/Fe oxides,which represents an important component of total barium in these sediments.Concentrations of biogenic barium obtained from the sequential extraction range from 104 to 445μg·g -1 ,and the average concentration was227μg·g -1 .The highest concentrations of biogenic barium occur in the central area of the bay,where the seawater is more stable,while lower values occur in the bank and the ice shelf.Biogenic barium is significantly linearly correlated with biogenic barium and organic carbon,and similar in distribution of Chl a,which may indicate that primary productivity of phytoplankton in the surface water column is the main environmental factor regulating barium concentration and distribution.