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 conce...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.展开更多
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 addit...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 Nino/La Nina-related succession during 1990 to 2002. In general, the number of algae species decreased during El Nino and La Nina 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 Nino years, and lagged behind the SST increases during La Nina 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 Nino and La Nina events. The relative proportion of diatoms increased, with that of dinoflagellates being decreased during El Nino years, while it was reversed during La Nina years.展开更多
The content and distribution of Ge is investigated in sediments from the Southern Ocean (Prydz Bay, Antarctica). The content of Ge total in the sediments ranges from 1.14×10-6 to 2.35×10-6 (average of 1.71&#...The content and distribution of Ge is investigated in sediments from the Southern Ocean (Prydz Bay, Antarctica). The content of Ge total in the sediments ranges from 1.14×10-6 to 2.35×10-6 (average of 1.71×10-6) and the highest value occurs at station P3-9 where water depth is > 1 000 m. The lowest value occurs at station P4-13 which is near the edge of the Amery ice shelf. The surface sediments have 16%-68% Ge bio within Ge total . The distribution trends of Ge bio and Ge total are generally similar, and the values outside Prydz Bay are higher than within the bay, bounded at 67°S. The vertical distribution of Ge in sediment cores presents higher values at the surface than in underlying sediments. Values of Ge bio appear to positively correlate with biogenic silica (BSiO 2) in surface sediments from non-polynyas sea. The vertical distribution of Ge bio and BSiO 2 is similar in sediments of station P3-16.展开更多
The concentrations and distributions of particulate biogenic silica (PBSi) in the upper surface waters of Prydz Bay, Antarctica, were investigated during the 27th Chinese National Antarctic Research Expedition cruises...The concentrations and distributions of particulate biogenic silica (PBSi) in the upper surface waters of Prydz Bay, Antarctica, were investigated during the 27th Chinese National Antarctic Research Expedition cruises of January 2011. We aimed to characterize the correlations between PBSi and plankton, nutrients and particulate organic carbon. The results showed that the concentrations of biogenic silica ranged from 0.76-19.72 μmol dm-3 and the average concentration of biogenic silica was 6.06 μmol dm-3 . The distribution of surface PBSi had significant regional characteristics: The concentrations were higher south of 67°S than to the north. The distribution of PBSi, chlorophyll a and particulate organic carbon showed similar patterns, and PBSi distribution had a negative correlation with that of silicate. In the vertical direction, the mole ratio of PBSi and POC (Sibio /Corg ) decreased with increasing depth. This trend indicated a higher rate of PBSi dissolution, or a lower rate of organic matter remineralization rate, in the upper 200 m.展开更多
Biomarkers 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 ...Biomarkers 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.展开更多
基金supported by the National Natural Science Foundation of China(Grant nos.41006118 and 41076134)the Chinese Polar Environment Comprehensive Investigation & Assessment Programmes(Grant no.CHINARE2012-04-04)
文摘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.
基金financially supported by the National Natural Science Foundation of China (NSFC) (40876104, 41306202, 41376193, 41076134 and 41006118)the scientific research fund of Second Institute of Oceanography, SOA (JT1208 and JG1218)+1 种基金Chinese Arctic and Antarctic Administration Foundation (20110208)the special fund for polar environment comprehensive investigation and assessment (CHINARE 2014-04-04, 2014-01-04 and 2014-04-01)
文摘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 Nino/La Nina-related succession during 1990 to 2002. In general, the number of algae species decreased during El Nino and La Nina 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 Nino years, and lagged behind the SST increases during La Nina 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 Nino and La Nina events. The relative proportion of diatoms increased, with that of dinoflagellates being decreased during El Nino years, while it was reversed during La Nina years.
基金supported by the National Natural Science Foundation of China (Grant nos.41076134,41206182)the Chinese Polar Environment Comprehensive Investigation & Assessment Programmes (Grant nos.CHINARE2013-04-01,CHINARE2013-01-04 and CHINARE2013-0404)
文摘The content and distribution of Ge is investigated in sediments from the Southern Ocean (Prydz Bay, Antarctica). The content of Ge total in the sediments ranges from 1.14×10-6 to 2.35×10-6 (average of 1.71×10-6) and the highest value occurs at station P3-9 where water depth is > 1 000 m. The lowest value occurs at station P4-13 which is near the edge of the Amery ice shelf. The surface sediments have 16%-68% Ge bio within Ge total . The distribution trends of Ge bio and Ge total are generally similar, and the values outside Prydz Bay are higher than within the bay, bounded at 67°S. The vertical distribution of Ge in sediment cores presents higher values at the surface than in underlying sediments. Values of Ge bio appear to positively correlate with biogenic silica (BSiO 2) in surface sediments from non-polynyas sea. The vertical distribution of Ge bio and BSiO 2 is similar in sediments of station P3-16.
基金supported by the National Natural Science Foundation of China (Grant no. 41076134 and 41206182)the Scientific Research Fund of the Second Institute of Oceanography, SOA (Grant nos.JT1009, JT1208, JG1217 and JG1218)+1 种基金the Chinese Polar Environment Comprehensive Investigation & Assessment Programmes (Grant nos. CHINARE 2012-01-04 and CHINARE 2012-04-04)the SOA Young Marine Science Foundation (Grant no. 2012536)
文摘The concentrations and distributions of particulate biogenic silica (PBSi) in the upper surface waters of Prydz Bay, Antarctica, were investigated during the 27th Chinese National Antarctic Research Expedition cruises of January 2011. We aimed to characterize the correlations between PBSi and plankton, nutrients and particulate organic carbon. The results showed that the concentrations of biogenic silica ranged from 0.76-19.72 μmol dm-3 and the average concentration of biogenic silica was 6.06 μmol dm-3 . The distribution of surface PBSi had significant regional characteristics: The concentrations were higher south of 67°S than to the north. The distribution of PBSi, chlorophyll a and particulate organic carbon showed similar patterns, and PBSi distribution had a negative correlation with that of silicate. In the vertical direction, the mole ratio of PBSi and POC (Sibio /Corg ) decreased with increasing depth. This trend indicated a higher rate of PBSi dissolution, or a lower rate of organic matter remineralization rate, in the upper 200 m.
基金supported by the National Nature Science Foundation of China under contract (Grant nos.40876104, 41006118 and 41076134)
文摘Biomarkers 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.
