کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
8912075 | 1639058 | 2017 | 42 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Succession of bacterial community structure and potential significance along a sediment core from site U1433 of IODP expedition 349, South China Sea
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
علوم زمین و سیارات
ژئوشیمی و پترولوژی
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چکیده انگلیسی
To evaluate the potential impact of geological processes and depositional history on shaping the subsurface biosphere, the bacterial community structures in a sediment core of the South China Sea was investigated by molecular approaches that target 16S rRNA gene fragments. Samples were obtained from different lithologic intervals at site U1433 during the International Ocean Discovery Program (IODP) Expedition 349. Bacterial abundance decreased rapidly with depth, with nearly three orders of magnitude decline within the first 100Â m below seafloor (mbsf). Community diversity displayed a similar decreasing pattern, yet, a slight increase in diversity emerged in the early to middle Miocene. Such excursion might reflect enhanced cell activity in response to increasing temperature due to a steep geothermal gradient. Non-metric multidimensional scaling ordination revealed that the bacterial communities along the sediment core represent four clusters based on depth and geological time. There were distinct bacterial community shifts among clusters at 4.50-98.93Â mbsf (Pleistocene), 108.15-273.20Â mbsf (Pleistocene), 296.09-709.13Â mbsf (Pliocene and late Miocene), and 732.10-789.91Â mbsf (early to middle Miocene). Classification analysis revealed a striking pattern: the relative abundance of microorganisms affiliated with Gammaproteobacteria, Actinobacteria, and Cyanobacteria overall consistently decreased with depth, whereas those affiliated with Chloroflexi, candidate division OP9, candidate phylum BHI80-139, and Nitrospirae increased; these findings correspond to different clusters. Total organic carbon content and ratio of total organic carbon: total nitrogen, along with pore water phosphate concentration and salinity, were the statistically most significant variables that explained the bacterial community cluster pattern, which indicates potential linkages of bacterial communities to changes in quality and quantity of buried organic matter over geological time scales. Geographic isolation across depth was more important than environmental condition and geological age for the development of unique community structure in marine deep biosphere, although environmental variables partially shaped bacterial community composition.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Marine Geology - Volume 394, 1 December 2017, Pages 125-132
Journal: Marine Geology - Volume 394, 1 December 2017, Pages 125-132
نویسندگان
Yao Zhang, Pan Liang, Xiabing Xie, Xiaofeng Dai, Haodong Liu, Chuanlun Zhang, Shuh-Ji Kao, Nianzhi Jiao,