Exploration of Fossil DNA-Based Geobiologic Archives to Reconstruct Hydrologic Changes in the Black Sea during the Holocene

摘要（Coolen OCE-0602423）迄今为止，基于DNA的沉积档案在海洋系统中仍然在很大程度上未被探索。该项目代表了古代DNA在大型海洋盆地的首次详细应用，以开发过去水柱结构的记录。研究所建议，在黑海全新世过去12 000年中，当该系统经历了剧烈的气候强迫的物理和化学变化时，开发平行的、高时间分辨率（50-100年）的基于DNA和脂质生物标志物的水柱和微生物群落结构的地层记录。有针对性的分子将包括微生物群落的标记居住在表面（藻类初级生产者），亚氧层（海洋Crenarchaeota），和硫化物化跃层（专性缺氧营养GSB），以提供信息，过去的地表水温度，盐度和分层变化在黑海。 将进行并行系统发育和脂质生物标志物分析，以仔细评估利用核糖体DNA和功能基因作为给定生物输入的代理的有效性，并评估推定生物前体中的种属变化对相应脂质生物标志物的分布和同位素组成的影响。该项目的主要目标包括：（1）研究DNA沉积档案中编码的古环境信息的广度和保真度，（2）DNA研究的应用，以进一步了解脂质生物标志物代用记录的实用性和局限性;（3）DNA和脂质分子地层学工具组合的应用，以完善气候解释。在全新世黑海驱动水文变化。该项目将成为WHOI/MIT联合项目学生博士论文的核心。认识到DNA可以在数千年的水生沉积物中保存下来，这是我们在研究气候与生物多样性之间关系的能力方面迈出的重要一步。

Abstract (Coolen OCE-0602423)To date, DNA-based sedimentary archives in marine systems have remained largely unexplored. This project represents the first detailed application of ancient DNA to a large marine basin in order to develop records of past water column structure. The PIs propose to develop parallel, high temporal resolution (50-100 yr) DNA and lipid biomarker based stratigraphic records of water column and microbial community structure in the Black Sea spanning the past 12,000 years of the Holocene when the system underwent dramatic climate-forced physical and chemical changes. Targeted molecules will include markers for microbial communities dwelling at the surface (algal primary producers), the suboxic layer (marine Crenarchaeota), and the sulfidic chemocline (obligate anoxyphotolithotrophic GSB) in order to provide information on past surface water temperature, salinity and stratification change in the Black Sea. Side-by-side phylogenetic and lipid biomarker analyses will be performed in order to carefully assess the validity of utilizing ribosomal DNA and functional genes as proxies of a given biological input and to assess the influence of species changes in the putative biological precursors on both the distribution and isotopic composition of corresponding lipid biomarkers. Primary objectives of this project include (1) An examination of the breadth and fidelity of paleoenvironmental information encoded in DNA sedimentary archives, (2) Application of DNA studies to further our understanding of the utility and limitations of lipid biomarker proxy records and (3) Application of combined DNA and lipid molecular stratigraphic tools to refine interpretations of climate-driven hydrologic changes in the Black Sea during the Holocene. This project will form the centerpiece of a PhD dissertation of a WHOI/MIT Joint Program student. The recognition that DNA can be preserved in aquatic sediments over many millennia represents an important step forward in our ability to examine the relationships between climate and biological diversity.