Spring twice sprung

I've been waiting for the right shot to qualify as my entry to this (actually last!) week's challenge - and now I discover I'm a day too late. Never mind! Today is the Vernal Equinox so spring has officially sprung.

And what can be seen here is the result of a spring tide. This is the underwater seaweed forest that's normally submerged several feet below the surface. Spring tides occur twice a month when the sun and moon are aligned at New Moon or at Full Moon resulting in a stronger than normal magnetic pull which produces both higher and lower than average tides. (Actually the word 'spring' in this case is nothing to do with the season but thought to be related to an old word for surge.) The opposite effect, when the sun and moon are not aligned, results in twice monthly 'neap' tides when the difference between high and low water is least.

The range of the spring tide is always greatest at the equinoxes but today's spectacular exposure of the submarine world is caused by a perigean spring tide, the moon last night being at its perigee, or the closest point in its ellipse to the Earth (also called the proxigee) and thus exerting an extra strong pull upon the tides. These rare occurrences can cause severe flooding and I see that today there are reports of people having to be rescued off beaches where the water has advanced beyond its usual limit.

It was a misty day in West Wales but my eyes were fixed upon the wonders uncovered on the sea floor: seaweeds held fast by their holdfasts (the star-shaped structure which grips the rock as in the foreground here), shellfish and sea anemones dotting the rocks, algae coloured pink and orange, and all manner of marine life awaiting the return of the sea's embrace.