There must be something special about certain tides or certain seasons or a combination of the two.  The beach was crowded with seaweed at low tide; wonder what it will look like tomorrow.  And where does it all go?  Back to the sea, to wash up again sometime later?  Does it stay alive until it washes back out?  Does it get buried in moving sand?  Does the whole coast look like this?  Does it move up and down the coast?  Does it get caught in rocks and jetties and piers?  The migration of seaweed…