Impact of temperature on microbial activity and carbon flow in deep hot sediments of the Guaymas Basin, Gulf of California (IODP Expedition 385)

温度对加利福尼亚湾瓜伊马斯盆地深层热沉积物中微生物活动和碳流的影响（IODP Expedition 385）

• 批准号: 467454634
• 负责人: Dr. Verena Heuer
• 金额: --
• 依托单位: Zentrum für Marine Umweltwissenschaften (MARUM)
• 依托单位国家: 德国
• 项目类别: Infrastructure Priority Programmes
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/467454634?language=en
• 关键词: Impact; temperature; microbial; activity; carbon

IODP Expedition 385 is investigating the tectonics and deep biosphere of the Guaymas Basin, a young marginal rift basin in the Gulf of California, at eight drilling sites. The geologic environment is characterized by active seafloor spreading and rapid deposition of sediments rich in organic material. Due to the high sedimentation rate, formation of new igneous crust involves the intrusion of sills into the thick overlying sediment burden. Sill emplacement presumably drives hydrothermal circulation, mobilizes carbon from sedimentary organic matter, and determines the distribution and activity of microbial communities. With the goal of investigating the interactions between tectonics and the deep biosphere, the expedition conducted in situ temperature measurements and collected numerous samples for microbiological and geochemical studies from deep sediments at temperatures as high as 120°C.Our goal with this project is to better understand microbial activity and carbon flux at the interface of the biological and geological carbon cycle. To do this, we are determining the relative abundance of microbial life in the form of dormant endospores, the production and turnover of the key metabolite acetate, and the sources and sinks of methane and higher hydrocarbon gases. Our investigations are focused on Sites U1545-U1548. Site U1545 and U1546 are located ~52 km northwest of the axial trench. The <0.44 million year old sediments are rich in organic material (up to 4 wt%) and hydrocarbon gases, and formation temperatures reach up to 120 °C. While Site U1546 contains a deep magma intrusion at a sediment depth of ~356-430 m, Site U1545 serves as a reference without sill intrusion. Sites U1547 and U1548 are located ~27 km northwest of the axial trench. They are located in the center and periphery of a circular hydrothermal hill called Ringvent. Both sites are affected by a slowly cooling sill intrusion encountered at ≥82 mbsf and ≥65 mbsf, respectively. The temperature range and high TOC content of the rapidly accumulating sediments are similar to those at Sites U1545 and U1546, but hydrothermal circulation has resulted in a geochemical regime dominated by sulfate-reducing conditions. This may provide a better energy supply for microorganisms compared to the northern sites. We will determine the distribution of endospores, acetate, and hydrocarbon gases in cores recovered from these sites and follow metabolic processes using stable isotope labeling experiments in the laboratory. The project aims to elucidate how microbial activity and carbon flux are determined by sediment temperature, geological and geochemical regimes.

IODP第385号考察队正在八个钻探地点调查加州湾一个年轻的边缘裂谷盆地瓜伊马斯盆地的构造和深层生物圈。地质环境的特点是海底扩张活跃，富含有机物质的沉积物迅速沉积。由于高沉积速率，新火成岩地壳的形成涉及岩床侵入厚的上覆沉积物负担。岩床侵位可能驱动热液循环，从沉积有机质中动员碳，并决定微生物群落的分布和活动。为了研究构造与深层生物圈之间的相互作用，该探险队进行了原位温度测量，并在高达120°C的温度下从深层沉积物中收集了大量样品用于微生物和地球化学研究。为此，我们正在确定休眠内生孢子形式的微生物生命的相对丰度，关键代谢物乙酸盐的生产和周转，以及甲烷和高级烃气体的来源和汇。我们的调查集中在场地U1545-U1548。地点U1545和U1546位于轴向海沟西北约52 km处。<44万年的沉积物富含有机物质（高达4wt%）和烃类气体，形成温度高达120 °C。虽然站点U1546在~356-430 m的沉积物深度处包含深岩浆侵入体，但是站点U1545用作没有岩床侵入体的参考。地点U1547和U1548位于轴向海沟西北约27公里处。它们位于一个叫做Ringvent的圆形热液山的中心和外围。这两个地点分别受到≥82 mbsf和≥65 mbsf的缓慢冷却岩床侵入的影响。温度范围和高TOC含量的快速积累的沉积物是类似的站点U1545和U1546，但热液循环导致的地球化学制度占主导地位的硫酸盐还原条件。与北方站点相比，这可以为微生物提供更好的能量供应。我们将确定内生孢子，乙酸盐和烃类气体的分布在从这些网站恢复的核心，并遵循代谢过程中使用稳定同位素标记实验室。该项目旨在阐明沉积物温度、地质和地球化学状况如何决定微生物活动和碳通量。