This is very dangerous.
Seedrian are plants, seedrians are like flowers, sea water is a poison to almost all plants. The only plants that survive the sea water are the coconut palms and a few species of tropical trees.
The sea water contains salt and iodine, this kills the plants.
Seaweeds are not plants, they are another species, Seaweeds do not belong to the plant kingdom.
Even though sea algae make photosynthesis equal to plants, yet sea algae so a very different species, sea algae do not have cellulose and chlorophyll.