Geograph - photograph every grid square

Three species of brown alga in clear water; they are adapted to grow at different levels on the shore, depending on how much drying-out they can stand. The three here are growing in different depths of water.
Channelled wrack [Pelvetia canaliculata], on the left, can stand the greatest exposure and grows at the highest level.
Bladder wrack [Fucus vesiculosus], in the middle with 'bubbles at the tips of the fronds, grows best at the middle tide level.
Knotted wrack [Ascophyllum nodosum], upper right with the knobbly stems, can stand little exposure to drying and grows at a lower level still.
The kelps, not shown here, grow at the very lowest level and only show at low water of spring tides.