An investigation of the physiology and potential role of components of the deep ocean bacterial community (of the NE Atlantic) by enrichments carried out under minimal environmental change
- 標題
- An investigation of the physiology and potential role of components of the deep ocean bacterial community (of the NE Atlantic) by enrichments carried out under minimal environmental change
- 作者
- Simon T. Egan, David M. McCarthy, John W. Patching, Gerard T.A. Fleming
- 文件屬性
- 國外期刊
- 知識分類
- 基礎研究
- 出版年
- 2012
- 刊名
- Deep Sea Research Part I: Oceanographic Research Papers
- 關鍵字
- Diversity; Deep-sea; Pressure; NE Atlantic; Bacterial community; 16S rDNA; PCR; DGGE
- 點閱數
- 2543
摘要
Samples of deep-ocean water (3170 m) taken from the Rockall Trough (North-East Atlantic) were incubated for one-month at atmospheric and in-situ pressure (31 MPa), at 4 °C and in the absence and presence of added nutrients. Prokaryotic abundance (direct cell counts) increased by at least 28-fold in enrichments without added nutrients. However, the magnitude of increase in abundance was less for incubations carried out at in-situ pressure (131–181-fold) than those incubations at surface pressure (163–1714-fold increase in abundance). Changes in the prokaryotic community profile as a result of one-month incubation were measured by means of Denaturing Gel Electrophoresis (DGGE) of extracted 16S rDNA. The profiles of post-incubation samples incubated at in-situ pressure were separated from all other profiles as were those of unpressurised samples with added nutrients. The behaviour (fitness) of individual community members (Operational Taxonomic Units: OTUs) was determined on the basis of change in relative DGGE band intensities between pre- and post-incubation samples. Of twenty-one OTUs examined, six were fitter when incubated in the presence of added nutrients and at in-situ pressure and one of these was advantaged when grown in the absence of added nutrients and at in-situ pressure. These represented autochthonous and active members of the deep-ocean prokaryotic community. In contrast, seven OTUs were disadvantaged when grown under in-situ pressure and were indicative surface-derived allochtonous microorganisms. A further two OTUs came to dominance in incubations with added nutrients (pressurised and unpressurised) and similar to the previous category were probably surface-derived microorganisms. A single OTU showed characteristics of piezophilic and oliogrophic behaviour and four OTUs were disadvantaged under all incubation conditions examined. The twenty-one DGGE bands were sequenced and the bacterial communities were dominated by Gamma proteobactria and to a lesser extent members of the Cytophaga–Flavobacterium–Bacteroides and δ groups of prokaryotes.