Sticky Stuff - Ocean Sciences Research Grant to study ripples on mudflats and beaches

Sand and mud banks form important barriers around our coastline. Researchers at Bangor University’s School of Ocean Sciences are to lead a major research project to assess how these fine materials are moved by water currents around our coastline, and how this movement could change as the result of climate change

The collaborative research project, funded by the Natural Environment Research Council and named COHBED, will investigate how the presence of cohesive, ‘sticky’ mud within sandy sediment influences the erosion, transport and deposition of this mixed sediment in seas and rivers. 

“The United Kingdom is a coastal nation with most people living within a few miles of the sea. Mud and sand are found in places where the energy of waves, tides and river flows is low and these water-borne sediments can be deposited on the sea floor. Muddy and sandy habitats are very important for the ecology and economy of the UK. They provide food for many species of birds and fish, but also protect the coastline from the erosive forces of the sea. They also act as a filter, where pollutants from the rivers are captured and eventually degraded. Because of the importance of these systems, their natural behaviour and stability is of increasing concern as sea levels rise with climate change”, explains Dr Jaco H. Baas, Lecturer at the School of Ocean Sciences and Principal Investigator of the project.

Dr Baas adds: “The main reason for setting up this project is that we have very little scientific information to help us to predict how natural mudflats and beaches will respond to the changing forces of the tides, wind and waves.  When water flows over the sea bottom, the energy of the flow shapes the sediment into wavy features,  such as ripples. These so-called bedforms help control the erosion and transport of sand, mud, nutrients and pollutants on a daily basis, but also in periods of storms, high rainfall and coastal flooding.”

“Information allowing us to predict the size and movement of bedforms is essential for many scientific disciplines, such as environmental management, hydraulic engineering, seabed habitat biology, computer modelling of particle transport and sedimentary geology. However, there is an almost complete lack of knowledge concerning bedforms consisting of mixtures of sand and mud. Sandy sediments are known to be ‘non-cohesive’, because the sand particles do not stick together, whereas muds are made up of smaller particles that do stick together and so are called ‘cohesive’ sediments. This difference is one of the study targets of the COHBED project.”  

The COHBED project is a collaboration with researchers from the National Oceanography Centre in Liverpool (Prof. Peter Thorne), and the Universities of Leeds (Dr Daniel Parsons), Plymouth (Dr Sarah Bass) and St Andrews (Prof. David Paterson), each contributing their specific expertise in physics, mathematics, sedimentology and biology to the project. The total budget is just under £1 million; this will help employ five Postdoctoral Researchers at the participating research institutes during various phases of the three year project, as well as one PhD student.

The COHBED project ranked joint second in the latest Standard Grant scheme of the Natural Environment Research Council. The award, in the field of sedimentology, follows hard on the heels of the recent ‘hat trick’ of successes in Physical Oceanography at the School of Ocean Sciences.

A large part of these investigations will be done through flow simulations in the School of Ocean Sciences’ Hydrodynamics Laboratory and ship-based work in the Dee estuary.

Publication date: 11 October 2011