This video is called Eelgrass (Zostera marina) underwater in Ireland.
Common eelgrass is a seagrass species. Till about 80 years ago, it was common in the Dutch Wadden Sea.
Then, it became extinct there, after a big dike separated the IJsselmeer fresh water from the salt water Wadden Sea, and after a seagrass disease epidemic.
Now, the Dutch Wadden Sea Society reports that an attempt to bring the eelgrass back to the Dutch Wadden Sea has started successfully. Last year, volunteers collected 100,000 seagrass plants near the German island Sylt.
They brought them to the Dutch Wadden Sea. It turns out that the plants are doing well.
More common eelgrass will be brought in from Germany.
Common eelgrass is important for fish laying eggs, and for young fish to hide. It makes a good environment for seahorses and pipefishes.
It also makes good food for brent geese.
See also here.
Per unit area, seagrass meadows can store up to twice as much carbon as the world’s temperate and tropical forests: here.
Seagrass on Dutch Rottum island: here.
Rare American Astrocaryum palm nut on Dutch Texel beach: here.