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

哈达尔带的深度为6,000-11000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。理解哈达尔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可能对海洋化学、氧化还原条件、营养物质的可获得性以及海洋和陆地上的生命产生重要影响。由于从哈达尔深度提取样品以供以后分析的固有困难，在这一研究领域取得阶段性变化的一个关键因素是能够使用传感器技术直接测量哈达尔沉积物和水柱中的重要生物地球化学参数，即不需要提取样本。国家海洋学中心(NOC)在开发用于公海的自主微型化学传感器方面处于世界领先地位。他们现有的技术已经在6000米深处进行了测试，可以测量从极地到热带地区环境中的各种化学物质。该项目将使NOC专家与新成立的超深海研究英才中心--南丹麦大学丹麦哈达尔研究中心(Hadal)的研究人员汇聚一堂，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：i)与双方合作伙伴开展知识交流和协作设计研讨会，以决定所需的传感器改装；ii)在Hadal压力测试设施中测试深度为6000米的传感器，以研究其局限性和需要改进的地方；以及iii)开发第一个概念验证数据集，在日本附近的深海海沟联合实地工作期间直接在哈达尔沉积物中测量营养物质。该项目的成果将回答有关深海海沟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，并将提供一个概念验证数据集，使我们能够通过为未来的合作撰写联合建议来加强合作。

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.