Collaborative Research: Anoxic Sediment Diagenesis at the Sulfate-Methane Interface: Does a Novel Microbial Syntrophy Result in Enhanced POC Remineralization?

摘要- Berelson 0433322大陆边缘沉积物中的有机碳分解或成岩作用是海洋沉积物中C循环的重要组成部分，因为其程度控制着长期的埋藏速率。来自南加州大学、加州理工学院和夏威夷大学的科学家们假设了一种新的成岩过程，当硫酸盐和甲烷同时存在时，该过程可能导致碳的矿化作用增强。 根据初步数据，这一过程似乎发生在一个本地化的水平（厘米厚），其中有一个微生物间的共生关系甲烷厌氧氧化的古细菌和硫酸盐还原菌。 他们将使用高分辨率孔隙水测量来研究圣巴巴拉盆地的沉积物，以创建化学梯度模型并计算扩散通量值。 微生物群落将使用总微生物细胞计数，古菌和细菌16 S rDNA和dsrAB为基础的社区表征，和荧光原位杂交（FISH）。 操纵培养实验将试图通过添加硫酸盐和/或甲烷来诱导更高的碳矿化速率。 缺氧海洋沉积物中这一独特区域的重要性对目前碳成岩作用的建模方法、海洋沉积物中古代理记录的解释以及对沉积物微生物群落生态学的一般理解具有潜在的重要意义。 微生物学家和两个地球化学家之间的合作将说明跨学科研究所创造的协同作用，以广泛的学生，包括REU，初中和高中学生，以及研究生和本科生参加这次合作的邮轮和数据分析。

ABSTRACT - Berelson 0433322Organic carbon breakdown, or diagenesis, within continental margin sediments is an important component of the C cycle in marine sediments as its extent controls long-term burial rates. Scientists from University of Southern California, California Institute of Technology and University of Hawaii have hypothesized a novel diagenetic process that may result in enhanced carbon remineralization when both sulfate and methane are present. Based on preliminary data, this process appears to occur at a localized horizon (cm's thick) where there is a microbial syntrophic relationship between anaerobic oxidation of methane by archaea and sulfate reducing bacteria. They will study sediments of the Santa Barbara Basin using high-resolution pore water measurements to create models of the chemical gradients and calculate diffusive flux values. The microbial community will be described using total microbial cell counts, archaeal and bacterial 16S rDNA and dsrAB-based community characterization, and fluorescent in situ hybridization (FISH). Manipulative incubation experiments will attempt to induce higher rates of carbon remineralization by the addition of sulfate and or methane. The importance of this unique zone in anoxic marine sediments has potentially significant implications to current modeling approaches to carbon diagenesis, interpretation of paleoproxy records in marine sediments and to general understanding of sediment microbial community ecology. Collaboration between a microbiologist and two geochemists will illustrate the synergies created by interdisciplinary research to a wide range of students including REU, middle and high school students, as well as the graduate and undergraduate students participating in this collaboration on cruises and in data analysis.