Hi, I am Clementine Chirol, third year PhD at the University of Southampton and proud member of the Science of Steart project. I like to describe myself as a mud scientist, but “lover of mud and shapes” might be a more appropriate description. In the scientific jargon, we call “geomorphology” the science that studies the shape of structures in the landscape, like mountains, rivers or coastlines, and how those structures change overtime.
Changes in the coastline are happening faster than ever under the combined effects of urban development and sea level rise. From spectacular cliff collapse in the UK to mangrove loss in India, coastal geomorphologists are afoot!
The alien beauty of marshes
Though not as striking as mangroves with their treacherous waters full of twisted roots, the saltmarshes you will typically find in the UK have their own austere beauty. In fact most people get very attached to this muddy environment on their first visit, quite literally if they don’t have proper footgear.
Alien and hostile though they may appear, saltmarshes do a lot for us. They provide habitats for rare species, act as natural flood defences, and are even more efficient at trapping carbon than rainforests. However they are being lost at an alarming rate across the world. This is due partly to sea level rise, but mostly to rapid urban development in coastal areas, which occurs three times faster than the mean global rate.
So clingy mud or no clingy mud, something must be done for our saltmarshes. Think of them as our cool and mysterious antiheroes in need of rescuing, even if slightly against their will.
Though the priority is to preserve natural marshes, plans have been made to create new artificial saltmarshes and replace the lost habitats. This is done by breaching a flood defence and letting the tide (and the mud!) back into previously reclaimed land. In north-western Europe, 102 such projects have been opened since 1981 (ABPmer, 2014).
But here’s the challenge: it takes decades of slow natural processes to create the shape of a mature saltmarsh, with its complex distribution of bumps and hollows, and its meandering channels. How good are we at reproducing those shapes with machines? And crucially, how will the chosen shape evolve overtime?
Here again the mud, and the tide that carries it, reign supreme. Erosion, transport and accumulation of mud can alter the saltmarsh as dramatically as rounds of protagonists’ assassination alter the political landscape in Game of Thrones, until the saltmarsh is at equilibrium with the strength of the tide.
I study the changes in shape of newly created saltmarshes across the UK. This involves a lot of trudging through mud to collect samples and measure rates of accumulation and erosion, but also some drier work like following the growth of tidal channels overtime in aerial photography.
Next time you visit your nearest saltmarsh, watch closely: it’s alive, and changing.