What is the “sea leash”?

Arnaud Guérin is a geologist and coastal specialist, he is the author of The beach, a hidden nature. He has just published his counterpart for children in the form of a holiday notebook, My beach diary published by Glénat jeunesse editions. He answers this question:

“You have to go back to the etymology of the word: it is what is ‘left’ by the tide. When you have a high tide, there is waste that will be left on the high beach. These are algae, pieces of vegetation, animal skeletons, even dead animals. And all that will start to rot on this high beach. It’s the beginning of an ecosystem, it will trap the sand and form small dunes .”

Arnaud Guerin

at franceinfo

“It comes from there, explains Arnaud Guérin. At low tide, in fact, the sand will be able to dry on the surface. It will be able to be carried away by the wind. But the grains are too large to be transported directly by the wind, they will make small successive leaps and they will stop as soon as there is an obstacle. The waterline is the first obstacle and therefore it will constitute a small pile of materials.

Plants will be able to develop in there and it is the beginning of the constitution of a dune. The Pilat dune, he adds, it is a very particular system which is linked to the existence of the Arcachon basin. The dry sand will be able to be carried away by the wind. And then behind, there is a forest, the Landes forest.

And all that, it blocks this huge pile of sand which is the only coastal dune in France, which is not made up thanks to the vegetation. And so we have a dune that is quite extraordinary. It is the highest dune in Europe, and it really is an absolutely fabulous site.”

In this holiday notebook, My beach diary, there are lots of little games, we do geography, we learn to have a different look at the beach and perhaps also to behave differently there?

“The goal of the game is to have a curious look. You can travel to the other side of the world to see wild nature, in fact, you have it just under your towel. It’s an invitation respecting this beach, respecting this absolutely extraordinary environment.”

Arnaud Guerin

at franceinfo

And as today we have already revised well, we close this Holiday notebook and see you tomorrow!