Beaches represent opposites of comfort for people: It is either sunny holiday places when the wind doesn’t blow, where surfers and sun tanners hang out and the ice cream is good, representing bliss. Or it is an inhospitable strip next to sea or lake where cold winds reign and waves wear down stone into sand continuously, soon to become a challenge, not much later a threat. The one becomes the other rather quickly.
Beaches are usually narrow, sloping strips of land along the edges of oceans, lakes and rivers, covered in sand, pebbles, rocks or fragments of seashell. All the parts are products of erosion and weathering, becoming smaller with sand as the destination for all.
Over many years the continual action of waves push rocky cliffs back imperceptibly by the smallest of decrements. The sand produced from all that was big and hard accumulates along the littoral, or is washed and blown away to unknown destinations above or below the water level.
The intertidal or littoral zone where land meets sea between high and low tide (in different places at different times) is full of favourite and visited spots on earth. This is a zone of much action for people and numerous animals; a bit like an airport, a railway station or international hotel. Almost everybody and everything that breathes seems to come here, although many appear ready for departure again soon.
To the uninitiated this may appear like a patch of empty sand. Not so! Life of a different ilk goes on here, as robust as in a tropical forest, albeit on a different physical scale. These worldwide ecosystem strips called beaches are rich in nutrients and attractive under different conditions, depending on ones species. Home to a variety of organisms not bent on ice cream, surfers or tanning, beaches are alive with interspecies events, even when the people have all gone home.
Meeting mates is another beach activity of the two-edged sword type, as some mates suddenly turn into predators. This holds for all species on the intra- and interspecies levels.
The longer one stays on the beach happily, the stronger one’s capacity for coping with changes from dry to wet, freezing to scorching, salinity between seawater and runoff or rain, not to speak of the turbulence of water and wind.
Persistent intertidal animals adapt in numerous ways. They burrow into the sand, shelter under or attach to rocks, assume and change colour or cover.
All of this helps to avoid being eaten or the opposite, to find food among the tasty fellow beach combers that double up as prospective diners. Hard learning when the range of shapes, sizes (and tastes) of those hanging out along the edges of two worlds is so vast.
If one’s innocence isn’t lost soon enough, one might be half digested before the vital point is taken.