Depending on the winds and currents, some of our largest beaches may be plagued by a sporadic stranding of green seaweeds in the summer. When this happens, they have to be removed quickly during the morning low tide before the tourists come in. It is an issue, not only because of the costs of tidying and of the bad image and smell on these days, but also because a lot of nice and fine sand is taken away from the beaches on these occasions, mixed with the seaweeds.
This phenomenon has gradually appeared over the last twenty years, because of the anarchic use of fertilizers in agriculture. Fertilizers that are spread over the fields are partly washed away by the rain. They end up in small rivers, that end up on the sea bottom close to the shores, where they fertilize … some annoying species of seaweeds. Brown seaweeds that grow slowly at mid depth have always been a valuable part of our eco-system in Brittany. They grow in the good season and the dying leaves and stems come ashore in the winter when it is cold. They are picked up by the farmers and get mixed as compost into the cultivated soil. On the other end, fertilizers favor the growth of different seaweeds species in the shallow waters close to the shore. These seaweeds are green, not brown, because they develop more chlorophyll in these smaller water depths. They grow fast and early in the season, therefore their dead leaves get already stranded in the warm season, when they would rot quickly on the crowded beaches if they were not forcefully picked up.
I really liked this image of your seaside village. The information in your narrative was so interesting too - we have similar problems with agricultural runoff - it's so hard to see a solution though.
August 5th, 2019
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