These plants are amazing, huge leaves float gently with the current, little air pockets grow among the stems, to keep the leaves afloat, the cell walls of the leaves are made up of cellulose ,this prevents them from drying out and gives structural flexibility. There are over 2000 species of brown algae.
There you are! Thank you SO MUCH for your majestic dialogue and totally wild photographs. Loved that you lost track of time in nature and Bert had to come looking for you!