The 16S and 18S ribosomal ribonucleic acid genes of microbial organisms collected from the contrasting environments （temperature, salinity, silicate, phosphate and nitrate, p 〈0.05） of the inner and outer basins of...The 16S and 18S ribosomal ribonucleic acid genes of microbial organisms collected from the contrasting environments （temperature, salinity, silicate, phosphate and nitrate, p 〈0.05） of the inner and outer basins of Kongsfjorden （Spitsbergen, Arctic） were studied using polymerase chain reaction-denaturing gradient gel electrophoresis（DGGE） fingerprinting. Comparison of the microbial fingerprints and the physicochemical parameters revealed that molecular methodology exhibited a greater sensitivity. Sequences obtained from bacterial DGGE were affiliated with four main phylogenetic groups of bacteria：Proteobacteria（Alpha, Beta and Gamma）, Bacteroidetes, Verrucomicrobia and Cyanobacteria. The relationships between the genotype distribution of these microbes and associated biotic/abiotic factors, revealed by canonical correspondence analysis, showed that Station 1 at 30 m （outer fjord） was grouped separately from the other sites. This difference could be a consequence of the thermocline and base of the euphotic layer at this depth where the Atlantic and Arctic-type waters overlapped.展开更多
The global warming leads to a large freshwater influx into the Arctic Ocean, which has adverse implications to the sea-ice dynamics, ocean circulation, and acidification. The relationship between oxygen isotope ratio(...The global warming leads to a large freshwater influx into the Arctic Ocean, which has adverse implications to the sea-ice dynamics, ocean circulation, and acidification. The relationship between oxygen isotope ratio(δ^(18)O) and salinity(S) is helpful in exploring various hydrographic processes related to the freshwater influx and is also required to accurately determine past salinity variability using oxygen isotope ratio of the carbonates. In view of this, systematic measurements of δ^(18)O and salinity of water from an Arctic fjord(Kongsfjorden) were carried out during the summer season of 2013. Until now, the relationships between δ^(18)O and salinity from such fjords were based on a limited number of samples collected during a very short span of time and thus may not accurately represent the long-term conditions prevailing in the fjord. The present study determines a more representative δ^(18)O-salinity relationship as water samples from different depths and location over a long period were systematically collected. The water samples were collected from four different locations at different depths along the axis of the fjord representing the inner and outer fjords. The inner stations(1-8 and 1-6) exhibit lowerδ^(18)O values than the outer stations(1-1 and 1-3), which indicate the higher influence of freshwater from glacial melting in the inner stations. The δ^(18)O-salinity relationship from the inner and outer fjords yield a slope of 0.54(r^2 = 0.67, n = 56) and 0.39(r^2 = 0.66, n = 68), respectively. The δ^(18)O of freshwater influx in the fjord is estimated at-18.4‰, which is close to the widely accepted freshwater-δ^(18)O value of the Arctic basin. The δ^(18)O of glacial discharge, which is the largest source of freshwater influx to the fjord, is estimated at ca.-21.0‰, which will be useful for future freshwater budget calculations.展开更多
基金supported by the National Natural Science Foundation of China (Grant Nos.41076130, 40576002)the International Cooperation Project of Science and Technology Commission of Shanghai Municipality (Grant no. 052307053)+1 种基金the Youth Marine Science Foundation of SOA (Grant no. 2010116)the Open Research Foundation of the SOA Laboratory of Marine Ecosystem and Biogeochemistry (Grant no. LMEB200902)
文摘The 16S and 18S ribosomal ribonucleic acid genes of microbial organisms collected from the contrasting environments （temperature, salinity, silicate, phosphate and nitrate, p 〈0.05） of the inner and outer basins of Kongsfjorden （Spitsbergen, Arctic） were studied using polymerase chain reaction-denaturing gradient gel electrophoresis（DGGE） fingerprinting. Comparison of the microbial fingerprints and the physicochemical parameters revealed that molecular methodology exhibited a greater sensitivity. Sequences obtained from bacterial DGGE were affiliated with four main phylogenetic groups of bacteria：Proteobacteria（Alpha, Beta and Gamma）, Bacteroidetes, Verrucomicrobia and Cyanobacteria. The relationships between the genotype distribution of these microbes and associated biotic/abiotic factors, revealed by canonical correspondence analysis, showed that Station 1 at 30 m （outer fjord） was grouped separately from the other sites. This difference could be a consequence of the thermocline and base of the euphotic layer at this depth where the Atlantic and Arctic-type waters overlapped.
基金the Secretary,Ministry of Earth Sciences and Director,NCAOR for support and encouragement(NCAOR Contribution No.37/2017)ISRO-GBP for support
文摘The global warming leads to a large freshwater influx into the Arctic Ocean, which has adverse implications to the sea-ice dynamics, ocean circulation, and acidification. The relationship between oxygen isotope ratio(δ^(18)O) and salinity(S) is helpful in exploring various hydrographic processes related to the freshwater influx and is also required to accurately determine past salinity variability using oxygen isotope ratio of the carbonates. In view of this, systematic measurements of δ^(18)O and salinity of water from an Arctic fjord(Kongsfjorden) were carried out during the summer season of 2013. Until now, the relationships between δ^(18)O and salinity from such fjords were based on a limited number of samples collected during a very short span of time and thus may not accurately represent the long-term conditions prevailing in the fjord. The present study determines a more representative δ^(18)O-salinity relationship as water samples from different depths and location over a long period were systematically collected. The water samples were collected from four different locations at different depths along the axis of the fjord representing the inner and outer fjords. The inner stations(1-8 and 1-6) exhibit lowerδ^(18)O values than the outer stations(1-1 and 1-3), which indicate the higher influence of freshwater from glacial melting in the inner stations. The δ^(18)O-salinity relationship from the inner and outer fjords yield a slope of 0.54(r^2 = 0.67, n = 56) and 0.39(r^2 = 0.66, n = 68), respectively. The δ^(18)O of freshwater influx in the fjord is estimated at-18.4‰, which is close to the widely accepted freshwater-δ^(18)O value of the Arctic basin. The δ^(18)O of glacial discharge, which is the largest source of freshwater influx to the fjord, is estimated at ca.-21.0‰, which will be useful for future freshwater budget calculations.
