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Peter Talling, National Oceanography Centre, UK
New insights into links between flow events, benthic biology and carbon fluxes: a proposal for co-ordinating international monitoring efforts at series of “global test sites”

Turbidity currents play a key role in submarine canyon dynamics and genesis, carrying sediment into deeper water to form the largest sediment accumulations on our planet. These submarine flows also supply organic carbon and nutrients; thus affect the dynamics of benthic ecosystems. In a stark contrast to other sediment transport processes such as rivers, it is sobering to note quite how few direct measurements we have from turbidity currents in action. Sediment concentration is the critical parameter controlling such flows, yet it has never been measured directly for flows that reach and build submarine fans. How then do we know what type of flow to model in flume tanks, or which assumptions to use to formulate numerical simulations or analytical models?

It is proposed here that international efforts are needed for an initiative to bring together monitor active turbidity currents with studies of benthic ecosystems and carbon transport; at a series of global ‘test sites’. Flows and ecosystems evolve significantly, such that source to sink data are needed. We also need to directly monitor flows and ecosystems in different settings with variable triggering factors and flow path morphologies because their character can vary significantly. Such work should integrate numerical and physical modelling with the collection of field observations in order to understand the significance of field observations.

This ‘test site’ initiative may be timely and feasible, due to recent technological advances in monitoring sensors, moorings and autonomous data recovery. This will be illustrated here by seminal field datasets recent collected by colleagues from the Squamish River Delta, Bute Inlet, Monterey Canyon, Congo Canyon and offshore SE Taiwan. This talk will conclude with some suggestions for appropriate test sites and collaborative approaches to future data collection. The initial phase of this proposal has been funded by the UK research councils, and input is sought into the design of the broader test site initiative.

Acknowledgements: This overview is based on a seminal body of recent flow monitoring work by international colleagues including John Hughes Clarke, Maria Azpiroz, Matthieu Cartigny, Michael Clare, Cortis Cooper, Stephanie Girardclos, Philip Hill, Gwynn Lintern, James Liu, Andrew Lin, Dan Parsons, Charlie Paull, Cooper Stacey, Esther Sumner, and Jingping Xu, amongst others.    

Theme 2: New ways to study submarine canyons: integrated programs, new technologies and coordinated monitoring efforts
Oral Presentation
turbidity current, ecosystem, carbon, global test sites