24 May 2023

Sea level for Welsh television

A while ago I got an email from some television production company. They were looking at doing a programme about sea level for the Welsh language TV channel S4C. Was I interested in collaborating? And of course I was! I love talking about sea level. And I love an opportunity to use my Welsh. So if I can do both at the same time I'm happy! They were also suggesting filming on location, which is nicer than filming in a lab or something. I had enjoyed it the previous time I had done that.

Their idea was that we would go somewhere where we could get hands-on and talk about sea level records. I am used to getting my sealevel records from salt marshes, but I also knew that that Newborough Marsh isn't very suitable for sea level studies. I didn't really know any North Welsh saltmarshes that were.

Then I thought about the work one of my colleagues, Mike Roberts, has done in the Menai Strait. He had a drill rig, and managed to retrieve a load of cores. These are basically grey sands and silts with sometimes a black layer in between: peat! Not only does peat indicate that the location was above sea level at the time of deposition, but you can also radiocarbon date it, so you know when exactly it was deposited. Lots of peat layers in your sediment core means you can build up a picture of sea level change through time. And an additional advantage is, that these peat layers stand out like sore thumbs, so it is easily explained to someone who is not used to looking at sediment cores. 

I don't know what happened to Mike’s cores, but I do know something else; every year, when I am on the beach with Lynda, the students spend the half day they are not spending with us with several of my colleagues on the tidal flat by Gallows Point, just outside Beaumaris. And there they sometimes take a core, with our percussion drill. This is not far from where Mike had been busy, and they do get beautiful peat layers in their sediment cores as well. 

I asked Martin, who is one of the staff members running the activities at Gallows Point, if that core would be available for this purpose. And he said yes! So that was the location and the material sorted. I had to go into the cold store and check, because I need to know what it is I will be showing a camera crew, but it all looked good. It was a five meter core with a beautiful peat layer at about 4 1/2 m deep. And from Mike's work I could have a reasonable guess at how old the layer would be.

We would meet on a Monday morning 7AM at Gallows Point. The Friday before I loaded up a hand corer, and the core, into one of the School vehicles I had borrowed for the occasion. At home I had a brilliant idea; I have a foldable table in the garage, that I had inherited from Rose; I should bring that! I wanted to show them the core in the field, but the field is a mud flat. You don't want to lay your beautiful cores down in the mud, and you don't want to have to crouch down to look at it with a TV presenter. If we would have it on the table, that would be way better for both the people and the core! So I stuck that in the School vehicle as well. And my rubber boots. I was ready to roll. Bring on the cameras! 

Ready to check the core!



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