Relatively short historical catch records show that anchovy populations have exhibited large variability over multi-decadal timescales.In order to understand the driving factors(anthropogenic and/or natural) of such v...Relatively short historical catch records show that anchovy populations have exhibited large variability over multi-decadal timescales.In order to understand the driving factors(anthropogenic and/or natural) of such variability,it is essential to develop long-term time series of the population prior to the occurrence of notable anthropogenic impact.Well-preserved fish scales in the sediments are regarded as useful indicators reflecting the fluctuations of fish populations over the last centuries.This study aims to validate the anchovy scale deposition rate as a proxy of local anchovy biomass in the Yellow Sea adjoining the western North Pacific.Our reconstructed results indicated that over the last 150 years,the population size of anchovy in the Yellow Sea has exhibited great fluctuations with periodicity of around 50 years,and the pattern of current recovery and collapse is similar to that of historical records.The pattern of large-scale population synchrony with remote ocean basins provides further evidence proving that fish population dynamics are strongly affected by global and basin-scale oceanic/climatic variability.展开更多
Aerophobetes （or CD12） is a recently defined bacterial phylum, of which the metabolic processes and ecological importance remain unclear. In the present study, we obtained the draft genome of an Aerophobetes bac- te...Aerophobetes （or CD12） is a recently defined bacterial phylum, of which the metabolic processes and ecological importance remain unclear. In the present study, we obtained the draft genome of an Aerophobetes bac- terium TCSI from saline sediment near the Thuwal cold seep in the Red Sea using a genome binning method. Analysis of 16S rRNA genes of TCS1 and close relatives revealed wide distribution of Aerophobetes in deep-sea sediments. Phylogenetic relationships showed affinity between Aerophobetes TCS 1 and some thermophilic bac- terial phyla. The genome of TCS1 （at least 1.27 Mbp） contains a full set of genes encoding core metabolic path- ways, including glycolysis and pyruvate fermentation to produce acetyl-CoA and acetate. The identification of cross-membrane sugar transporter genes further indicates its potential ability to consume carbohydrates preserved inthe sediment under the microbial mat. Aerophobetes bac- terium TCS1 therefore probably carried out saccharolytic and fermentative metabolism. The genes responsible for autotrophic synthesis of acetyl-CoA via the Wood-Ljung- dahl pathway were also found in the genome. Phylogenetic study of the essential genes for the Wood-Ljungdahl pathway implied relative independence of Aerophobetes bacterium from the known acetogens and methanogens. Compared with genomes of acetogenic bacteria, Aero- phobetes bacterium TCS 1 genome lacks the genes involved in nitrogen metabolism, sulfur metabolism, signal trans- duction and cell motility. The metabolic activities of TCS 1 might depend on geochemical conditions such as supplies of CO2, hydrogen and sugars, and therefore the TCSI might be a facultative bacterium in anaerobic saline sedi- ments near cold seeps.展开更多
基金supported by the National Basic Research Program (973 Program 2010CB428902)the National Natural Science Foundation of China (40876088)
文摘Relatively short historical catch records show that anchovy populations have exhibited large variability over multi-decadal timescales.In order to understand the driving factors(anthropogenic and/or natural) of such variability,it is essential to develop long-term time series of the population prior to the occurrence of notable anthropogenic impact.Well-preserved fish scales in the sediments are regarded as useful indicators reflecting the fluctuations of fish populations over the last centuries.This study aims to validate the anchovy scale deposition rate as a proxy of local anchovy biomass in the Yellow Sea adjoining the western North Pacific.Our reconstructed results indicated that over the last 150 years,the population size of anchovy in the Yellow Sea has exhibited great fluctuations with periodicity of around 50 years,and the pattern of current recovery and collapse is similar to that of historical records.The pattern of large-scale population synchrony with remote ocean basins provides further evidence proving that fish population dynamics are strongly affected by global and basin-scale oceanic/climatic variability.
基金supported by the Strategic Priority Research Program of the Chinese Academy of Sciences (XDB06010201)the National Natural Science Foundation of China (41476104)+3 种基金supported by the Strategic Priority Research Program (XDB06010102)an award from the King Abdullah University of Science and Technology (SA-C0040/ UK-C0016) to P.Y. QianV.B. Bajic was supported by KAUST Base Research FundsS. Bougouffa was supported by a SABIC postdoctoral fellowship
文摘Aerophobetes （or CD12） is a recently defined bacterial phylum, of which the metabolic processes and ecological importance remain unclear. In the present study, we obtained the draft genome of an Aerophobetes bac- terium TCSI from saline sediment near the Thuwal cold seep in the Red Sea using a genome binning method. Analysis of 16S rRNA genes of TCS1 and close relatives revealed wide distribution of Aerophobetes in deep-sea sediments. Phylogenetic relationships showed affinity between Aerophobetes TCS 1 and some thermophilic bac- terial phyla. The genome of TCS1 （at least 1.27 Mbp） contains a full set of genes encoding core metabolic path- ways, including glycolysis and pyruvate fermentation to produce acetyl-CoA and acetate. The identification of cross-membrane sugar transporter genes further indicates its potential ability to consume carbohydrates preserved inthe sediment under the microbial mat. Aerophobetes bac- terium TCS1 therefore probably carried out saccharolytic and fermentative metabolism. The genes responsible for autotrophic synthesis of acetyl-CoA via the Wood-Ljung- dahl pathway were also found in the genome. Phylogenetic study of the essential genes for the Wood-Ljungdahl pathway implied relative independence of Aerophobetes bacterium from the known acetogens and methanogens. Compared with genomes of acetogenic bacteria, Aero- phobetes bacterium TCS 1 genome lacks the genes involved in nitrogen metabolism, sulfur metabolism, signal trans- duction and cell motility. The metabolic activities of TCS 1 might depend on geochemical conditions such as supplies of CO2, hydrogen and sugars, and therefore the TCSI might be a facultative bacterium in anaerobic saline sedi- ments near cold seeps.
