22 Jun 2016

Runswick's naval mine (an unusual habitat).

Somewhere in the seaweed-covered rocks beyond the morass of stinkily-decaying seaweed there was rumoured to be a WW2 naval mine. Today I went on an expedition to find it, and on the far edge of the bit of the beach known as Jarvis' Landing Hole I stumbled across it:
The beach hereabouts is uncharacteristically rocky; I think this is the debris from when the village of Runswick (bar one house) and much of the cliff on which it was built slipped into the sea in 1682. The mine is probably WW2; it there are several small holes in its case which suggests it was sunk by gunfire; it's estimated there are 1.3 million tonnes of unexploded WW2 munitions on the bed of the North Sea. It was now become a rather snug home for barnacles (lots of juveniles) and limpets.
Lots of limpets means food for whelks; this one's a bit out of focus, and has a necklace of juvenile limpets growing on its shell:
The mine's explosive filling is long gone, inside it's shaded and there is a permanent rock pool which is home to flustra, saw wrack, red algae, crabs and amphipods:
The mine is at the part of the beach where knotted wrack (Ascophyllum nodosum - seen here with lots of its parasitic red Polysiphonia lanosa):

  is replaced by saw wrack (Fucus serratus):
A stream that drains the rockpools further up the beach runs around the old mine; it provides a home for beadlet anemones and Pomatoceras triquiter.
And, wedged under the bottom of the mine, an ammonite counterpart, home to a topshell and a very well camouflaged chiton (it's at the ammonite's 12 o'clock):

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