BIO

The oceans are a major repository for atmospheric carbon. An important component of the global carbon cycle is the ocean's biological carbon pump (BCP), which is dominated by the sinking of organic particles from the surface ocean to its interior. Of the material generated via phytoplankton primary production in surface waters, most is recycled in the upper ocean. A small fraction is exported to the deep ocean and sequestered away from further contact with the atmosphere on timescales of hundreds to thousands of years. Both the size and efficiency of the BCP are predicted to decline globally in response to climate change, potentially resulting in reduced ocean carbon storage and hence increased atmospheric carbon dioxide levels. Therefore, accurately quantifying the magnitude and efficiency of the global BCP is essential to understanding the Earth's carbon cycle and the impact of continued anthropogenic inputs of carbon dioxide. However, current estimates of the strength of the BCP range 4-fold, suggesting that despite more than 30 years of study, no consensus on its magnitude has yet been reached. There is even more uncertainty about what controls the efficiency of the BCP and its variability on seasonal timescales. Recently, a new parameterisation of the export ratio (which describes the efficiency of the upper ocean BCP) was developed by the PI and co-authors. This suggested that the BCP efficiency was substantially lower than previously thought. However, our parameterisation of the export ratio has relatively large uncertainty at cold sea surface temperature. The export ratio is thought to be driven in large part by the type of phytoplankton present in the upper ocean, because large, dense phytoplankton sink rapidly and export more efficiently than smaller plankton. Our hypothesis is that the variability in export ratio at low temperatures is due to strong seasonality in phytoplankton bloom evolution at high latitudes, driven by temporal shifts in phytoplankton community structure. This project will assess how seasonal variability of the phytoplankton bloom alters the export ratio in the sub-Arctic through a combination of in situ and satellite data based studies. We propose to collate measurements of upper ocean particulate organic carbon flux and simultaneous phytoplankton community structure from two high latitude regions with suitably cold SST and strong variability in phytoplankton blooms. This project will use data to be collected on a UK Ocean Acidification Research Programme cruise to the Arctic (work already funded by NERC), and on a cruise to the Labrador Sea, for which funds are requested here. We propose to participate in an existing cruise in May 2012 (funded by DFO Canada) to take additional measurements of export flux and phytoplankton community structure. The variability in bloom stage and PCS encountered during the cruises will be used to determine the impact of seasonal gradients in bloom conditions on the export efficiency. We will then apply the understanding gained from the regional studies to a global database of export measurements, using satellite-derived data on sea surface temperature, bloom stage and phytoplankton community structure. We will then develop a revised parameterisation of the export ratio, including relevant seasonal information and in the final stage of the proposed work, apply our revised parameterisation globally to calculate a new estimate of the magnitude of the BCP. The project aims to gain understanding of controls on seasonal variability in the export ratio, and hence reduce uncertainty in the estimate of global BCP magnitude.

UK-OSNAP: Summary What is climate? The sun's energy is constantly heating the Earth in equatorial regions, while in the Arctic and Antarctic the Earth is frozen and constantly losing heat. Ocean currents and atmospheric weather together move heat from the equator towards the poles to keep the Earth's regional temperatures in balance. So climate is simply the heat moved by ocean currents and by the weather. Earth's climate is warming: the average temperature of the Earth is rising at a rate of about 0.75 degrees Centigrade per hundred years, caused by carbon dioxide in the atmosphere trapping heat that is normally lost to space. Can we forecast how climate might change in the future? There is an old adage that rings true: "Climate is what you expect; weather is what you get". Hot weather in one summer does not tell us that climate is changing because the weather is so variable day-to-day and even year-to-year. We need to average over all the weather for a long time to decide if the climate is changing. We would like to know if the climate is changing before our descendants face the consequences, and that is where our project comes in. The ultimate ambition of climate scientists is nothing less than forecasting climate up to 10 years in advance. Is this possible? After all we know weather forecasts become somewhat unreliable after three to five days. The answer is yes because of the ocean. Slow and deep currents give the ocean a memory from years to hundreds of years, and the ocean passes this memory onto the climate. If we know the condition of the ocean now, then we have a good chance of understanding how this will affect the climate in years to come. We have set ourselves a huge task, but will be helped by colleagues in the US, Canada, Germany, Netherlands, Faroe Islands, Iceland, Denmark and Scotland. We will continuously measure the ocean circulation from Canada to Greenland to Scotland (the subpolar North Atlantic Ocean). This has never been attempted before. We have chosen the North Atlantic because the circulation here is important for the whole of Earth's climate. This is because in the high latitudes of the North Atlantic, and the Arctic Ocean that it connects to, the ocean can efficiently imprint its memory on the atmosphere by releasing the huge amounts of heat stored in it. In the UK we are on the same latitude as Canada and Siberia, and the Shetland Islands are further north than the southern tips of Greenland and Alaska, but the Atlantic Ocean circulation keeps the UK 5-10 degrees Centigrade warmer than those other countries. We can measure across an entire ocean by deploying reliable, self-recording instruments. We will use moorings (wires anchored to the seabed and supported in the water by air-filled glass spheres) to hold the instruments in the important locations. Every year from 2014 to 2018 we will use ships to recover the moorings and the data, then put the instruments back in the water. We will also use exciting new technology. Autonomous underwater Seagliders will fly from the surface to 1 km depth on year long-missions surveying the ocean, from Scotland to 2000 km westward into the Atlantic. The Seagliders transmit their data to our lab every day via satellite, and the pilot can fly the glider remotely. Also there is a global fleet of 3000 drifting floats to continuously measure the top 1 km of the ocean. Satellites provide important measurements of the ocean surface. With these new measurements, we will find how the heat carried by the ocean changes through the months and years of the project, and we will use complex computer models to help explain what we find.

UK-OSNAP: Summary What is climate? The sun's energy is constantly heating the Earth in equatorial regions, while in the Arctic and Antarctic the Earth is frozen and constantly losing heat. Ocean currents and atmospheric weather together move heat from the equator towards the poles to keep the Earth's regional temperatures in balance. So climate is simply the heat moved by ocean currents and by the weather. Earth's climate is warming: the average temperature of the Earth is rising at a rate of about 0.75 degrees Centigrade per hundred years, caused by carbon dioxide in the atmosphere trapping heat that is normally lost to space. Can we forecast how climate might change in the future? There is an old adage that rings true: "Climate is what you expect; weather is what you get". Hot weather in one summer does not tell us that climate is changing because the weather is so variable day-to-day and even year-to-year. We need to average over all the weather for a long time to decide if the climate is changing. We would like to know if the climate is changing before our descendants face the consequences, and that is where our project comes in. The ultimate ambition of climate scientists is nothing less than forecasting climate up to 10 years in advance. Is this possible? After all we know weather forecasts become somewhat unreliable after three to five days. The answer is yes because of the ocean. Slow and deep currents give the ocean a memory from years to hundreds of years, and the ocean passes this memory onto the climate. If we know the condition of the ocean now, then we have a good chance of understanding how this will affect the climate in years to come. We have set ourselves a huge task, but will be helped by colleagues in the US, Canada, Germany, Netherlands, Faroe Islands, Iceland, Denmark and Scotland. We will continuously measure the ocean circulation from Canada to Greenland to Scotland (the subpolar North Atlantic Ocean). This has never been attempted before. We have chosen the North Atlantic because the circulation here is important for the whole of Earth's climate. This is because in the high latitudes of the North Atlantic, and the Arctic Ocean that it connects to, the ocean can efficiently imprint its memory on the atmosphere by releasing the huge amounts of heat stored in it. In the UK we are on the same latitude as Canada and Siberia, and the Shetland Islands are further north than the southern tips of Greenland and Alaska, but the Atlantic Ocean circulation keeps the UK 5-10 degrees Centigrade warmer than those other countries. We can measure across an entire ocean by deploying reliable, self-recording instruments. We will use moorings (wires anchored to the seabed and supported in the water by air-filled glass spheres) to hold the instruments in the important locations. Every year from 2014 to 2018 we will use ships to recover the moorings and the data, then put the instruments back in the water. We will also use exciting new technology. Autonomous underwater Seagliders will fly from the surface to 1 km depth on year long-missions surveying the ocean, from Scotland to 2000 km westward into the Atlantic. The Seagliders transmit their data to our lab every day via satellite, and the pilot can fly the glider remotely. Also there is a global fleet of 3000 drifting floats to continuously measure the top 1 km of the ocean. Satellites provide important measurements of the ocean surface. With these new measurements, we will find how the heat carried by the ocean changes through the months and years of the project, and we will use complex computer models to help explain what we find.

Turbidity currents are the volumetrically most import process for sediment transport on our planet. A single submarine flow can transport ten times the annual sediment flux from all of the world's rivers, and they form the largest sediment accumulations on Earth (submarine fans). These flows break strategically important seafloor cable networks that carry > 95% of global data traffic, including the internet and financial markets, and threaten expensive seabed infrastructure used to recover oil and gas. Ancient flows form many deepwater subsurface oil and gas reservoirs in locations worldwide. It is sobering to note quite how few direct measurements we have from submarine flows in action, which is a stark contrast to other major sediment transport processes such as rivers. Sediment concentration is the most fundamental parameter for documenting what turbidity currents are, and it has never been measured for flows that reach submarine fans. How then do we know what type of flow to model in flume tanks, or which assumptions to use to formulate numerical or analytical models? There is a compelling need to monitor flows directly if we are to make step changes in understanding. The flows evolve significantly, such that source to sink data is needed, and we need to monitor flows in different settings because their character can vary significantly. This project will coordinate and pump-prime international efforts to monitor turbidity currents in action. Work will be focussed around key 'test sites' that capture the main types of flows and triggers. The objective is to build up complete source-to-sink information at key sites, rather than producing more incomplete datasets in disparate locations. Test sites are chosen where flows are known to be active - occurring on annual or shorter time scale, where previous work provides a basis for future projects, and where there is access to suitable infrastructure (e.g. vessels). The initial test sites include turbidity current systems fed by rivers, where the river enters marine or freshwater, and where plunging ('hyperpycnal') river floods are common or absent. They also include locations that produce powerful flows that reach the deep ocean and build submarine fans. The project is novel because there has been no comparable network established for monitoring turbidity currents Numerical and laboratory modelling will also be needed to understand the significance of the field observations, and our aim is also to engage modellers in the design and analysis of monitoring datasets. This work will also help to test the validity of various types of model. We will collect sediment cores and seismic data to study the longer term evolution of systems, and the more infrequent types of flow. Understanding how deposits are linked to flows is important for outcrop and subsurface oil and gas reservoir geologists. This proposal is timely because of recent efforts to develop novel technology for monitoring flows that hold great promise. This suite of new technology is needed because turbidity currents can be extremely powerful (up to 20 m/s) and destroy sensors placed on traditional moorings on the seafloor. This includes new sensors, new ways of placing those sensors above active flows or in near-bed layers, and new ways of recovering data via autonomous gliders. Key preliminary data are lacking in some test sites, such as detailed bathymetric base-maps or seismic datasets. Our final objective is to fill in key gaps in 'site-survey' data to allow larger-scale monitoring projects to be submitted in the future. This project will add considerable value to an existing NERC Grant to monitor flows in Monterey Canyon in 2014-2017, and a NERC Industry Fellowship hosted by submarine cable operators. Talling is PI for two NERC Standard Grants, a NERC Industry Fellowship and NERC Research Programme Consortium award. He is also part of a NERC Centre, and thus fulfils all four criteria for the scheme.

Turbidity currents are the volumetrically most import process for sediment transport on our planet. A single submarine flow can transport ten times the annual sediment flux from all of the world's rivers, and they form the largest sediment accumulations on Earth (submarine fans). These flows break strategically important seafloor cable networks that carry > 95% of global data traffic, including the internet and financial markets, and threaten expensive seabed infrastructure used to recover oil and gas. Ancient flows form many deepwater subsurface oil and gas reservoirs in locations worldwide. It is sobering to note quite how few direct measurements we have from submarine flows in action, which is a stark contrast to other major sediment transport processes such as rivers. Sediment concentration is the most fundamental parameter for documenting what turbidity currents are, and it has never been measured for flows that reach submarine fans. How then do we know what type of flow to model in flume tanks, or which assumptions to use to formulate numerical or analytical models? There is a compelling need to monitor flows directly if we are to make step changes in understanding. The flows evolve significantly, such that source to sink data is needed, and we need to monitor flows in different settings because their character can vary significantly. This project will coordinate and pump-prime international efforts to monitor turbidity currents in action. Work will be focussed around key 'test sites' that capture the main types of flows and triggers. The objective is to build up complete source-to-sink information at key sites, rather than producing more incomplete datasets in disparate locations. Test sites are chosen where flows are known to be active - occurring on annual or shorter time scale, where previous work provides a basis for future projects, and where there is access to suitable infrastructure (e.g. vessels). The initial test sites include turbidity current systems fed by rivers, where the river enters marine or freshwater, and where plunging ('hyperpycnal') river floods are common or absent. They also include locations that produce powerful flows that reach the deep ocean and build submarine fans. The project is novel because there has been no comparable network established for monitoring turbidity currents Numerical and laboratory modelling will also be needed to understand the significance of the field observations, and our aim is also to engage modellers in the design and analysis of monitoring datasets. This work will also help to test the validity of various types of model. We will collect sediment cores and seismic data to study the longer term evolution of systems, and the more infrequent types of flow. Understanding how deposits are linked to flows is important for outcrop and subsurface oil and gas reservoir geologists. This proposal is timely because of recent efforts to develop novel technology for monitoring flows that hold great promise. This suite of new technology is needed because turbidity currents can be extremely powerful (up to 20 m/s) and destroy sensors placed on traditional moorings on the seafloor. This includes new sensors, new ways of placing those sensors above active flows or in near-bed layers, and new ways of recovering data via autonomous gliders. Key preliminary data are lacking in some test sites, such as detailed bathymetric base-maps or seismic datasets. Our final objective is to fill in key gaps in 'site-survey' data to allow larger-scale monitoring projects to be submitted in the future. This project will add considerable value to an existing NERC Grant to monitor flows in Monterey Canyon in 2014-2017, and a NERC Industry Fellowship hosted by submarine cable operators. Talling is PI for two NERC Standard Grants, a NERC Industry Fellowship and NERC Research Programme Consortium award. He is also part of a NERC Centre, and thus fulfils all four criteria for the scheme.