The climate and ecological emergencies, Brexit and Covid-19 illustrate the enormity of change and disturbance currently impacting coastal communities in the UK, and the urgency of building resilience to accelerating, multi-faceted and new forms of risk. Our research aims to build the knowledge and know-how to enhance the resilience of marine resource-users to environmental, regulatory and socio-cultural change, while simultaneously improving their wellbeing and reducing adverse impacts on the marine environment. Marine investment, policy and management decisions are often understood as prioritisation decisions ("this or that"), but they can also involve system interactions and trade-offs, and so create winners and losers. Trade-off conflicts manifest in policy consultation, planning and licensing decisions, and in the everyday behaviours of resource-users choosing to support (or not) particular interventions. There is, therefore, increasing impetus to be explicit about trade-offs where they can explain the political acceptability, effectiveness and durability of marine plans, fisheries regulations, protected area designations or offshore wind farms. To date, research has focused on ecological trade-offs or social-ecological trade-offs related to tensions between environmental sustainability and human welfare and wellbeing, with little attention to resilience. Yet, emerging research shows trade-offs between resilience and wellbeing, and between resilience and sustainability with important implications for marine policy and practice. Our research will be the first to develop a nexus perspective on resilience, wellbeing and sustainability to acknowledge that any solution for one objective must equally consider the other two in the nexus. We apply the nexus perspective to on-the-ground and policy interventions to systematically evaluate synergies and trade-offs among resilience, wellbeing and sustainability across scales and sectors, and to identify opportunities to improve these outcomes together. We address the three call themes by: THEME 1: Investigating how diverse marine resource-users respond to varied disturbance events, how their resilience intersects with their wellbeing and engagement with sustainability, and what they VALUE as important for maintaining and improving nexus outcomes. THEME 2: Applying the nexus perspective to the policy context to understand how diverse values and nexus dynamics are traded off in decision-making currently. Working closely with policy and industry stakeholders we will develop a DECISION-SUPPORT FRAMEWORK to interrogate the acceptability of trade-off decisions within and across marine sectors. THEME 3: Applying the nexus perspective to on-the-ground INTERVENTIONS to assess how initiatives intend to improve resilience, wellbeing and/or sustainability, and currently deal with trade-offs across the nexus. Working closely with practitioners, we will identify opportunities to improve future iterations of these interventions so they can better deliver triple benefits across the nexus. Project deliverables include: a new nexus perspective; a low-tech trade-off decision-support framework for use by policy-makers and implementers, and; evidence that applying a nexus perspective can improve both policy and on-the-ground interventions in marine social-ecological systems in the UK across the domains of marine heritage, sustainable development of communities, and marine environmental regulation. This research will be world leading and of international importance. The resilience of people, communities and ecosystems underpins global action to sustainably manage aquatic ecosystems (SDG14), respond to climate change (SDG13), and deliver enduring improvements in wellbeing (SDG1+2). Our research addresses a significant gap in knowledge of how nexus dynamics play out across scales that will be fundamental to successful delivery of these Sustainable Development Goals.

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.

The oceans contain only about 1.5% of terrestrial biomass. However, they provide a similar amount of total annual production to that on land and the turnover time for organic matter is 1000-times faster in marine in comparison to terrestrial ecosystems. This highlights that grazing by zooplankton is disproportionally important and competition among grazers is high. It is not surprising that phytoplankton have evolved mechanisms to protect themselves from grazers. These include morphological defences such as grazing-resistant shells, for example in 'armoured' dinoflagellates, and chemical defences such as sophisticated chemical deterrence that influence the selectivity of grazers. Over the years we have accumulated a good understanding of the role of chemical defences in the bitrophic interactions between predators and their prey. However, it is also well known that land plants use another cunning defence strategy that involves the production of volatile signalling compounds (so called infochemicals) that attract the enemy of their predators. This in turn reduces the number of herbivores and releases the plants from excessive grazing pressure. Surprisingly, such infochemical-mediated tritrophic interactions have not been documented for oceanic plankton and our proposed research will rectify this shortcoming. We will focus our activities on one particular marine volatile: dimethyl sulphide (DMS). This compound is probably the best-studied of all marine trace gases, because much interest in DMS research concerns its role in regulating climate. We are starting to appreciate that DMS also has ecological importance and find that many organisms can use plumes of DMS as directional cue for their orientation. For example, some sea birds use DMS to locate areas of high food density. Recently, we also found that zooplankton copepods react to DMS gradients. Copepods are dominant consumers of microzooplankton protists (unicellular ciliates and flagellates) that are important grazers of many small phytoplankton species. In biogeochemical terms ciliates account for, on average, 30 % of the carbon consumed by copepods, representing approximately 5 % of total oceanic primary production and 100 fold the annual fisheries catch (~ 100 Mt yr-1 live weight) in carbon terms. However, these estimates may be considerably higher if other components of the microzooplankton, in particular dinoflagellates, are included. Interestingly, grazing by microzooplankton can result in a dramatic increase of DMS production and this is dependent on the ability of the phytoplankton to make this gas. Hence, phytoplankton may actively influence the 'smelliness' of their predators and this likely makes their enemies more susceptible to copepod attack. It is then not surprising that many of the DMS-producing phytoplankton species are competing successfully and can produce algal blooms that are large enough to be seen from space (for example the coccolithophore Emiliania huxleyi) or can be harmful to other organisms (for example toxic dinoflagellates). Our project will use laboratory experiments where we will quantify grazing of microzooplankton and copepods in relationship to the ability of phytoplankton to make DMS. These data will enable a first assessment of grazing-induced production of DMS in a tritrophic framework. We will also conduct field experiments with freshly collected plankton to verify our laboratory results with data from coccolithophore-dominated waters off Plymouth and in the North-East Atlantic. Our data will inform modelling efforts that aim to predict the effect of differential production of DMS on the susceptibility of microzooplankton to copepod grazing and the fecundity of copepods. This part of our project will be realised through a tied PhD studentship.