Global climate change is one of the big challenges society faces today. Warming of the climate system is unequivocal, and evident from observations of increasing global average temperatures. Warming is also observed in the oceans, and is accompanied by a change in salinity, with the high latitudes becoming 'fresher' (i.e., less saline) and the subtropics and tropics becoming more saline - a redistribution of properties that has the potential to affect ocean circulation. There are also clear effects of climate change on the chemistry of the oceans. Whilst increased uptake of more abundant atmospheric carbon dioxide leads to an acidification of the oceans that threatens marine ecosystems, only little is known about the effects of higher concentrations of certain trace metals, as a result of anthropogenic pollution and changing erosion patterns on land. Such changes are very important, however, as the ability of the ocean to take up carbon dioxide from the atmosphere is strongly coupled to the supply of so-called nutrients, elements that are essential for life in the ocean. As part of this project, we will develop a better understanding of such 'biogeochemical cycles'. We picked out three trace metals, neodymium (Nd), cadmium (Cd), and lead (Pb), which together represent the behaviour of many different elements in the ocean. For example, both Cd and Pb are today supplied to the environment by human activity and this may alter their natural cycles. As Cd is an important micronutrient in the ocean, such changes could also affect the global carbon cycle. As part of our project, a PhD student will focus on understanding whether the natural flux of dust from desert areas to the ocean and the anthropogenic particles the dust scavenges in the atmosphere have an important impact on the marine Cd and Pb cycles. The student will furthermore study, how the cycling of these elements in the ocean is altered by changing oxygen concentrations. Oxygen is (next to the nutrients) another important player in biogeochemical cycles, and its solubility in seawater is temperature dependent. Climate models predict that extended zones with low oxygen concentrations will develop in the future oceans. Another important aspect of the ocean system is that ocean currents are the key mechanism for distributing heat, and thus they have a significant impact on regional and local climate. Furthermore, water mass movements (both vertical and lateral) are very important for the carbon cycle, as the deep ocean contains 50-60 times more carbon than the atmosphere. Today we can monitor ocean circulation by measuring the physical properties of seawater. Observations over the past 50 years, however, do not give us any clear indication whether the pattern of ocean circulation is changing. From studies of the past we know, however, that ocean water masses had a different configuration during the ice ages and past periods of extreme warmth. Neodymium isotopes in seawater are often used for such reconstructions, and the results show stunning relationships between past temperatures, carbon dioxide levels, and ocean circulation. A patchy understanding the modern Nd cycle however limits our confidence in such reconstructions, and thus our ability to transfer the inferred mechanisms to future models. In particular, it is generally assumed that away from ocean margins, Nd isotopes are an ideal ocean circulation tracer as they are only modified by mixing between water masses. However, there are many potential marine processes, which may not be in accord with this simplistic view. Such uncertainties will be addressed by the current project, based on a comprehensive suite of new observational data that will be collected for samples from strategic locations in the Atlantic Ocean. In conjunction with modelling efforts, our new data will shed light on the processes governing the marine Nd cycle and the suitability of Nd isotopes as circulation tracer.

We propose a programme of observations, combined with analysis of past and ongoing time series, to discover the magnitude of surface pH variations at seasonal-up-to-decadal time scales. We will address the Atlantic, UK shelf and slope waters, and selected locations in the Southern Ocean, using data from time series stations and volunteer observing ships (VOS), measuring three parameters of the marine carbonate system. The programme will be integrated with the efforts of colleagues in other European countries, (enablng better and longer-term coverage, and of of a wider area). It will be co-ordinated with the Surface ocean carbon atlas project (SOCAT) which aims to produce the most comprehensive and up to date data base to access all the quality data relevant to ocean carbon uptake, and from which pH trends can be derived. Estimation of decadal trends change will be set against the background of intra- and inter-annual variation.

Worldwide, seaweed aquaculture has been developing at an unabated exponential pace over the last six decades. China, Japan, and Korea lead the world in terms of quantities produced. Other Asiatic countries, South America and East Africa have an increasingly significant contribution to the sector. On the other hand, Europe and North America have a long tradition of excellent research in phycology, yet hardly any experience in industrial seaweed cultivation. The Blue Growth economy agenda creates a strong driver to introduce seaweed aquaculture in the UK. GlobalSeaweed: - furthers NERC-funded research via novel collaborations with world-leading scientists; - imports know-how on seaweed cultivation and breeding into the UK; - develops training programs to fill a widening UK knowledge gap; - structures the seaweed sector to streamline the transfer of research results to the seaweed industry and policy makers at a global scale; - creates feedback mechanisms for identifying emergent issues in seaweed cultivation. This ambitious project will work towards three strands of deliverables: Knowledge creation, Knowledge Exchange and Training. Each of these strands will have specific impact on key beneficiary groups, each of which are required to empower the development of a strong UK seaweed cultivation industry. A multi-pronged research, training and financial sustainability roadmap is presented to achieve long-term global impact thanks to NERC's pump-priming contribution. The overarching legacy will be the creation of a well-connected global seaweed network which, through close collaboration with the United Nations University, will underpin the creation of a Seaweed International Project Office (post-completion of the IOF award).

We propose a programme of observations, combined with analysis of past and ongoing time series, to discover the magnitude of surface pH variations at seasonal-up-to-decadal time scales. We will address the Atlantic, UK shelf and slope waters, and selected locations in the Southern Ocean, using data from time series stations and volunteer observing ships (VOS), measuring three parameters of the marine carbonate system. The programme will be integrated with the efforts of colleagues in other European countries, (enablng better and longer-term coverage, and of of a wider area). It will be co-ordinated with the Surface ocean carbon atlas project (SOCAT) which aims to produce the most comprehensive and up to date data base to access all the quality data relevant to ocean carbon uptake, and from which pH trends can be derived. Estimation of decadal trends change will be set against the background of intra- and inter-annual variation.

In modern marine environment, 30-50% of nitrogen lost from the ocean is due to anaerobic ammonium oxidation (anammox). This bacterial process removes an important nutrient, nitrogen, from the marine phytoplankton system. Thus, anammox has a direct consequence on global marine primary production, the uptake of carbon dioxide, and the carbon cycle. Anammox bacteria performing this process are only active in low-oxygen to anoxic settings, included oxygen minimum zones (OMZs) in the water column. OMZs are expanding in our current changing climate and it is important to understand how this expansion will affect anammox activity and in turn the carbon cycle. Reconstructing paleoclimate in analogs for modern and future climate allows us to study how future changes will affect elements like the anammox processes. There are several instances in Earth's climate history when expanding OMZ has led to full-scale oceanic anoxia. Anammox bacteria are members of a deep-branching phylum, and the process has been hypothesised to have played an important role in creating and maintaining oceanic anoxia during crucial periods of Earth's history (e.g. Jurassic and Cretaceous Oceanic Anoxic Events (OAEs)). Determining how anammox was involved in these past scenarios will help better predict what likely outcomes we can expect in our future. Organic geochemistry uses molecular fossils, called biomarkers, to study the impact microbial processes have had on the environment. Currently, tracing anammox bacteria using biomarkers is done using ladderane lipids. However, the applicability of a biomarker has temporal limitations. For example, the inability to withstand degradative processes, which occur during and after deposition, restricts how far back in time these biomarkers can be applied. Although ladderane lipids are excellent biomarkers for modern environments, they are highly labile and not well suited for tracing past anammox activity. Thus, in order to clarify the role anammox has played during these past extreme climate events, lipids must first be identified that can be used as biomarkers in more mature sediments. Two distinct lipid classes have shown potential as biomarkers for past anammox, and will be assessed in this project. These lipids will be evaluated and will be implemented to trace anammox in past oceanic settings. The first class (bacteriohopanepolyols, specifically BHT isomer) seem suitable for sediments deposited within the last 50 Ma, and that have not been exposed to thermal stresses after burial. For example, we will apply these biomarkers to a 2 Myr sediment record underlying the Peru OMZ to explore the hypothesis that anammox influences the expansion of OMZs by contributing to nitrogen removal during increased OMZ. The second class (unusual cyclic and branched long-chain alkanes) extends the time window of detection into thermally mature sediments. These biomarkers will be investigated in OAE events to determine how anammox influenced a shift towards nitrogen-fixation being the dominate pathway of nutrient uptake during OAEs. Additionally, these alkanes will be economically benefit project partners in the petroleum industry, where biomarkers for anoxia would indirectly indicate preservation potential of organic matter and petroleum. We will create a simplified method for anammox detection that we will disseminate to other geochemistry laboratories for their studies of the anammox process. Combined, these findings and those specifically from our system studies will help understand past nitrogen cycling by using our established biomarkers to trace past anammox activity. Finally, the results of our studies of paleo-anammox will be incorporated into the biogeochemical model GENIE. This will improve our understanding of the role anammox played in past nitrogen cycling. Subsequently, model results will help to better predict the implications of anammox on future nitrogen and carbon cycling under our changing climate.