The ocean plays a vital role in sustaining life on planet Earth, providing us with living resources and regulating climate. Ocean observations are required to understand how the ocean and climate has changed in the past and to characterise the status of the marine environment and its resources today. Furthermore, global ocean observations are essential for skilful forecasts needed for planning, resource management, policy development and restoring ocean health. The Argo array of profiling temperature and salinity floats has transformed our ability to understand and predict sea level change, ocean heat content and sea surface temperature and their impacts on weather, climate, ecosystems, people and infrastructure. The Argo array has a dual role in providing initial conditions for predictive systems and in driving new process understanding that has led to model improvement. However, major ocean biogeochemical challenges including understanding the ocean's role in anthropogenic carbon uptake, de-oxygenation of the global oceans, and ocean productivity and health are not addressed by the Core Argo array. BioGeoChemical Argo (BGC Argo) builds on the success of the Argo array through the addition of biogeochemical sensors for pH, oxygen, nitrate, chlorophyll, suspended particles and downwelling irradiance. Data from BGC Argo will drive a transformative shift in the understanding of biogeochemical cycling in the ocean and its dynamics at large scales: processes which have a profound impact on a rapidly changing climate, ocean productivity and health. Transformation will come through the acquisition of data with unprecedented space and time resolution, which was impossible before the development of BGC floats. BGC floats already produce more oxygen profiles per year than all research ships combined. The BGC Argo Science and Implementation Plan calls for a global array. Pilot arrays have demonstrated the capacity to build the global array, but to date only a handful of the deployed floats have measured all 6 BGC parameters. The UK, through the G7 Future of the Seas and Oceans Initiative, has committed to contributing to the BGC Argo array. Having recently secured funding for 9 UK BGC floats (~15% of expected UK array), NOC has begun to deliver on that commitment and to develop a national facility for quality-control and distribution of the profile data in a timely way. We will procure and deploy a further 16 BGC Argo floats in the Atlantic (~25% of UK array), all equipped with the 6 parameters required by international Argo. Resources for deployment and lifetime costs of providing quality-controlled, open-access data for this step-change in capability are in place through Climate Linked Atlantic Sector Science (CLASS) National Capability cruises and the British Oceanographic Data Centre. CLASS will fund a float coordinator to manage the floats and influence the development of the global array through the international Argo governance system.

Nitrogen-containing compounds, including glycine betaine (GBT), choline and trimethylamine N-oxide (TMAO) are ubiquitous in marine organisms. They are used by marine organisms as compatible solute in response to changes in environmental conditions, such as increasing salinity, because they do not interfere with cell metabolisms. They also have beneficial effects in protecting proteins against denaturation due to chemical or physical damages. In the marine environments, these compounds are frequently released into the sea water due to the change of environmental conditions, such as viral attack or grazing. The released nitrogenous osmolytes serve as important nutrients for marine microorganisms, which can use them as carbon, nitrogen and energy sources. It is well known that the degradation of these nitrogenous osmolytes contribute to the release of climate-active gases, including volatile methylated amines. Methylated amines are important sources of aerosols in the marine atmosphere, which help to reflect sunlight and cause a cooling effect of the climate. There is an urgent need to understand the microbial metabolism of these compounds and their seasonal cycles in the marine water column, in order to better understand their role in marine biogeochemical cycles and their role in future climate change. Built on the recent progress on the discovery of the new pathway of TMAO degradation in marine organisms and the development of a powerful liquid chromatography with mass spectrometry (LC-ESI-MS) method for simultaneous quantification of these nitrogenous osmolytes from the applicants' laboratories, this timely proposal aims to determine the seasonal cycle of nitrogenous osmolytes in the surface seawater and to address how these environmentally-relevant compounds are degraded and what are the major microorganisms that are involved in the process. The data generated will fill in a major gap in our knowledge of marine carbon and nitrogen cycles and the contribution of these compounds in future climate change through the release of climate-active molecules. Using newly developed analytic techniques, we aim to determine the seasonal cycle of standing concentrations of nitrogenous osmolytes in the surface seawater and microbial oxidation activities. These data will be incorporated to a biogeochemical model for future prediction of biogeochemical cycles of N-osmolytes under climate change. Using cultivated model organisms, we aim to define the key genes, enzymes and the metabolic pathways in GBT and TMAO degradation by marine planktonic microbes. Using molecular and single cell manipulation techniques, we aim to further determine the key microbial players involved in the metabolism of nitrogenous osmolytes in surface seawater from the English Channel. This work will generate novel knowledge about our understanding of microbial transformation of these nitrogen containing compounds, and will fill in a serious gap in knowledge of marine carbon and nitrogen cycles. The project is expected to further strengthen the UK as a leading country not only in the research of marine biogeochemical cycles and marine microbiology, but also in the development of cutting edge technology in environmental science.

Doctoral Training Partnerships: a range of postgraduate training is funded by the Research Councils. For information on current funding routes, see the common terminology at https://www.ukri.org/apply-for-funding/how-we-fund-studentships/. Training grants may be to one organisation or to a consortia of research organisations. This portal will show the lead organisation only.