Friday, 21 October 2011

Sticky Stuff

Sandbanks provide natural defences, reducing coastal erosion, and behave in ever changing but predictable ways. Scientists can run models which will plot the size and location of sandbanks as sea levels rise in response to climate change and this is useful to inform planning decisions. The trouble is that sand and pure sandbanks are only part of the story – much of the sediment on earth is not sand but mud or a mix of mud and sand.   

Mud and sand
Where the sediment is sand you get a rippled effect and the length and height of the ripples reflects the flow and the amount of energy passing over that bit of the seabed. These patterns of sediment are called ‘bedforms’. Where the sediment is mud, or a mix with sand, the bedforms are much more flat and less mobile.

Sand is firm to walk on whilst mud is clawing and squelchy. Mud is sticky or cohesive whilst sand is non-cohesive. What makes mud so sticky is the volume of negatively charged particles of clay and the degree and types of excretion by many different creatures.

Dr Jaco Baas
The £1m COHBED (COHesive BEDforms) project has been set up by NERC to fill the gap in our understanding, and improve our ability to model and plan for the future. Bangor University are 1 of the 5 universities working on the project. 

If you’d like to know more about this project you should listen in to Radio Wales Country Focus, sometime in November, when Dr Jaco Baas will explain the finer points of ‘sticky stuff’.

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