How did marimo end up on a beach in Schull?

Last week, a reader wrote, “Sir, I live in West Cork since four months. I come from Brittany.

West Cork is a marvellous place! Yesterday, I made a little walk on the strand in Schull. I found many “green moss” bowls on the sand. Could you help me to resolve the mystery of the Green Moss Bowls of Schull?” A photo of a handful of spherical green balls of moss followed.

I will be frank; I had never seen these ‘things’ in Ireland. But the photo jogged a memory; I had seen something similar in a Tokyo fish market when I lived in Japan in the mid-1970s. I wondered what they were at the time, but thought them to be man-made, or man-woven, another example of Japanese minaturism, art and ingenuity.