Quantifying the contribution of the deep biosphere in the marine sediment carbon cycle using deep-sea sediment cores from the Baltic Sea

使用波罗的海深海沉积物岩心量化深层生物圈在海洋沉积物碳循环中的贡献

• 批准号: 1431598
• 负责人: Karen Lloyd
• 金额: $ 36.21万
• 依托单位: University of Tennessee Knoxville
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-09-01 至 2017-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1431598&HistoricalAwards=false
• 关键词: Quantifying; contribution; deep; biosphere; marine

Marine sediments contain a microbial population large enough to rival that of Earth's oceans, but much about this vast community is unknown. Innovations in total cell counting methods have refined estimates of cell concentrations, but tell us nothing about specific taxa. Isotopic data provides evidence that a majority of subsurface microorganisms survive by breaking down organic matter, yet measurable links between specific microbial taxa and their organic matter substrates are untested. The proposed work overcomes these limitations, with a particular focus on the degradation of proteins and carbohydrates, which comprise the bulk of classifiable sedimentary organic matter. The project will link specific taxa to potential extracellular enzyme activity in the genomes of single microbial cells, apply newly-identified, optimal methods for counting viable cells belonging to specific taxa using catalyzed reporter deposition fluorescent in situ hybridization (CARD-FISH), and measure the potential activity of their enzymes in situ. The resulting data will provide key evidence about the strategies subsurface life uses to overcome extreme energy limitation and contribute to the long-term carbon cycle. The Principal Investigators are employing novel,improved methods to quantify cells of specific taxa in the marine subsurface and to determine the biogeochemical functions of those uncultured taxa, including: 1)Determine the pathway of organic carbon degradation in single cell genomes of uncultured, numerically dominant subsurface microorganisms. 2)Quantify viable bacteria and archaea in the deep subsurface using an improvement on the existing technology of CARD-FISH. 3)Measure the potential activities (Vmax values) of enzymes in deep Baltic Sea sediments, and use the abundances of enzyme-producing microorganisms to calculate depth profiles of cell-specific Vmax values. The project combines these methods in order to identify and quantify the cells capable of degrading organic matter in deep sediments of the Baltic Sea, obtained from Integrated Ocean Drilling Program (IODP) expedition 347. These results will greatly expand our knowledge of the function and activity of uncultured microorganisms in the deep subsurface.

海洋沉积物中的微生物数量足以与地球海洋中的微生物相媲美，但关于这个庞大的群落，人们还不清楚。总细胞计数方法的创新改进了对细胞浓度的估计，但没有告诉我们具体的分类群。同位素数据提供的证据表明，大多数地下微生物通过分解有机物而生存，但特定微生物类群与其有机物基质之间的可测量联系尚未得到验证。拟议的工作克服了这些局限性，特别注重蛋白质和碳水化合物的降解，其中包括大部分可分类的沉积有机物。该项目将把特定分类群与单个微生物细胞基因组中潜在的胞外酶活性联系起来，应用新确定的最佳方法，利用催化报告沉积荧光原位杂交（CARD-FISH）计数属于特定分类群的活细胞，并原位测量其酶的潜在活性。由此产生的数据将提供有关地下生命用于克服极端能量限制并促进长期碳循环的策略的关键证据。主要研究人员正在采用新的，改进的方法来量化海洋地下特定类群的细胞，并确定这些未培养类群的生物地球化学功能，包括：1）确定未培养的，数量占主导地位的地下微生物的单细胞基因组中有机碳降解的途径。 2)使用对现有CARD-FISH技术的改进，量化深层地下的活细菌和古菌。3)测量波罗的海深海沉积物中酶的潜在活性（Vmax值），并使用产酶微生物的丰度来计算细胞特异性Vmax值的深度剖面。该项目将这些方法结合起来，以确定和量化能够降解波罗的海深层沉积物中有机物的细胞，这些细胞是从综合大洋钻探计划（IODP）347考察中获得的。这些结果将大大扩展我们对深层地下未培养微生物的功能和活性的认识。