New capabilities for measuring organic matter degradation in the deepest oceans on Earth

深达6000-11000米，占海洋深度范围的近一半，但直到最近才被认为是有机碳周转和微生物活动的潜在热点。了解hadal沉积物中的碳矿化和相关的生物地球化学过程具有全球重要性，因为沉积物中的碳循环对海洋化学、氧化还原条件、养分有效性以及海洋和陆地上的生命都具有重要意义。由于从深海深处提取样品用于后期分析的固有困难，在这一研究领域取得阶段性进展的一个关键因素是能够使用传感器技术直接测量深海沉积物和水柱中的重要生物地球化学参数，即不需要提取样品。国家海洋学中心（NOC）在开发用于开放海洋的自主小型化化学传感器方面处于世界领先地位。他们现有的技术已经经过了6000米深度的测试，可以测量从极地到热带环境中的各种化学物质。该项目将汇集NOC专家和来自新成立的超深海研究卓越中心的研究人员：南丹麦大学（SDU）的丹麦Hadal研究中心（Hadal），共同提高我们对深海海沟有机碳降解过程的认识。为了实现这一目标，我们将与HADAL中心的参与者共享资源，以便：i)与双方合作伙伴进行知识交流和协作设计研讨会，以决定所需的传感器适应方式；ii)在HADAL压力测试设施中测试传感器至b> 6000米的深度，以研究其局限性和所需的改进；iii)在日本深海海沟的联合实地工作期间，开发第一个直接测量HADAL沉积物中营养物质的概念验证数据集。该项目的成果将回答有关深海海沟中有机碳降解过程及其对周围生态系统影响的令人兴奋的研究问题，并将提供概念验证数据集，使我们能够通过为未来的合作撰写联合提案来加强合作。

The hadal zone, with depths of 6000-11000 m, accounts for nearly half of the ocean's depth range, but has only recently been recognized as potential hotspot for organic carbon turnover and microbial activity. To understand the carbon mineralization and the related biogeochemical processes in hadal sediments is of global importance as carbon recycling in sediments can have critical implications for ocean chemistry, redox conditions, nutrient availability and hence for life in the oceans and on land. Due to inherent difficulties of retrieving samples for later analyses from hadal depths, a key element to make step changes in this field of research is the ability to use sensor technology to measure the important biogeochemical parameters directly in the hadal sediments and water column, i.e. without retrieving samples. The National Oceanography Centre (NOC) are world-leaders in developing autonomous miniaturized chemical sensors for use in the open ocean. Their existing technology has been tested to 6000 m depth and can measure a wide range of chemicals in environments from the polar regions to the tropics. This project will bring together NOC experts with researchers from the newly created centre of excellence for ultra-deep sea research: the Danish Center for Hadal Research (HADAL) at the University of Southern Denmark (SDU) to jointly improve our knowledge about the processes governing organic carbon degradation in deep-sea trenches. In order to achieve this, we will share resources with the HADAL Center participants, to: i) conduct a knowledge exchange and a collaborative design workshop with both partners to decide on required sensor adaptations ii) test the sensors at the HADAL pressure testing facility to depths > 6000 m to study their limitations and required improvements, and iii) develop the first proof of concept data set of nutrients measured directly in hadal sediments during joint field work to a deep-sea trench off Japan. The outcomes of this project will answer exciting research questions about organic carbon degradation processes in deep-sea trenches and their impact on the surrounding ecosystem and will provide a proof-of-concept data set that will position us to strengthen the collaboration by writing joint proposals for future collaborations.