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

Lead Research Organisation: National Oceanography Centre (WEF011019)
Department Name: Science and Technology


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.


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Description One of the objectives of this project is to test if the Lab-on-Chip sensors, build at the National Oceanography Centre (NOC) in Southampton, can operate at higher pressure than previously tested (i.e. 6000 m water depth) and hence can give information about one of the least explored environments on Earth, i.e. hadal trenches. Due to COVID-related travel restrictions, pressure tests to up to 11000 m water depth should have been performed at the HADAL Center in Denmark, but were postponed to later in the projects; instead additional tests at the NOC showed that the Lab-on-Chip sensors still can function at water depth of 6900 m. This is currently the highest pressure the sensors have been tested at.
Due to COVID-related travel restrictions, the participation in a research expedition to an hadal trench was until now not possible. Instead, we demonstrated in a local river that the Lab-on-Chip sensors can resolve tidal variations of nitrate in sediments and can continuously measure in sediments over days. With this, we have not only demonstrated the functioning of the sensors in the sediment for the first time, but also the very high variability of nitrate concentrations in sediments in relation to tides, which (to our knowledge) has not been measured at this temporal resolution.
Exploitation Route Novel and unique geochemical dataset; knowledge and technology that can be used e.g. by industry, environmental agencies and scientists to understand dynamic geochemical changes in the environment and to monitor environmental impacts on benthic habitats.
Sectors Chemicals,Energy,Environment

Description HADAL Centre 
Organisation University of Southern Denmark
Country Denmark 
Sector Academic/University 
PI Contribution With this project we initiated the partnership with the Danish Center for Hadal Research (HADAL), which is a centre of excellence funded by the Danish National Research Foundation, to collaborate and perform knowledge exchange in this field of research.
Collaborator Contribution The partner provides knowledge, a high pressure testing facility and (in future) access to research cruises.
Impact Too early to say
Start Year 2020
Description Press release 
Form Of Engagement Activity A press release, press conference or response to a media enquiry/interview
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Industry/Business
Results and Impact Press release in the context of the OCEAN BUSINESS meeting, Southampton, which is an Ocean Technology Exhibition and training forum.
Year(s) Of Engagement Activity 2020