Deep biosphere quantification in various marine sediments

考虑到各种深埋海洋沉积物的异质性和目前可获得的有限的活微生物数量数据集，目前还无法对深海生物圈的大小作出可靠的全球估计。因此，该项目的总体目标是对不同沉积物地点（开阔海域、大陆边缘、上升流区）进行比较、定量的微生物群落分析，以获得海洋深层生物圈的一般知识，并使全球深层生物圈的估计得以更新。在之前的项目中建立的实时PCR （Q-PCR）和催化报告沉积-荧光原位杂交（CARD - FISH）分子定量技术将得到验证，并在必要时进行改进，并应用于来自313号考察队新泽西浅陆架、大西洋中脊23°N西侧7 Ma北塘地区和纳米比亚外本格拉上升流地区的深埋沉积物样本。此外，将在培养实验中研究加热对微生物群落的影响，以澄清目前文献中关于原核生物在海底沉积物中占主导地位的矛盾。

Considering the heterogeneity of the various deeply-buried marine sediments and the currently available limited data set on numbers of living microorganisms, reliable global estimates of the size of the deep biosphere can not be drawn yet. The overall goal of the project is therefore the comparative, quantitative microbial community analysis of different sediment sites (open ocean, continental margin, upwelling area) to gain knowledge for the marine deep biosphere in general and to enable an update of global estimates of the deep biosphere. The molecular quantification techniques real-time PCR (Q-PCR) and Catalyzed Reporter Deposition - Fluorescence In Situ Hybridisation (CARD - FISH) established within the previous projects shall be verified and if necessary improved and applied to deeply-buried sediment samples from the Expedition 313 New Jersey Shallow Shelf, from North Pond area in 7 Ma Western Flank of the Mid-Atlantic Ridge 23°N, and from the Benguela upwelling area off Namibia. In addition, the effect of heating on the microbial community will be studied in incubation experiments to clarify the present contradictions in the literature regarding which prokaryotes dominate sub-seafloor sediments.