Thankfully, the weather looked set fair for the afternoon. However, the state of the tide did not look promising but Jenny assured the assembled 10 members that the beach and rocks would definitely be revealed in due course……..

Meanwhile, she was keen to tell us the differences between Felpham Beach where she took us in 2021 and where we were now on Aldwick Beach.  Beneath Bognor Regis and the surrounding area lies a sequence of rocks that were deposited as sediments between 90 and 50 million years ago. These sediments were deposited as layers of mud and sand and the different layers or beds reflect the changing climate and rising and falling of the sea relative to the land. Millions of years of earth movements have subsequently produced a succession of rocks along our coastline so that Felpham is on the Chalk bed which is about 90 million years old whereas Aldwick is on the London Clay formation which is about 50 million years old. Fascinating stuff, and meantime, behold, true to the predicted tide timetable, the sea had ‘rapidly’ retreated revealing the sandy beach and the Bognor Rocks (the eroded remnant of the Bognor Rock Bed.)

We set up a table as a base and equipped with hand lenses, guides and net we split up to search the many rocks, working our way westwards towards the Mulberry harbour relic. Amongst the seaweeds spotted (remembering the gradient of green to brown to red as one goes down the beach, showing the adaptation to different levels of sunlight) was much Serrated wrack as well as Sea lettuce, Gut weed, Irish or Carrageenan moss, Sea oak and several other red seaweeds. On the fronds of some Serrated wrack, Jenny pointed out Sea mat, an intriguing lacy, mesh-like growth.

A remarkable number of Anemones ( mainly beadlet) were recorded, tucked away in the pools on the top of the rocks. A spectacular anemone with lines of spots on its body evaded identification (possibly a Strawberry or possibly not!) Similarly, there was discussion about the many oysters clinging to the rocks, most thought to be the non native Pacific oyster. There were the usual Common limpets and Barnacles (including Acorn and some Austrominius) . Also recorded on IRecord were Periwinkle, Masked crab, Keel worm and great fun was had poking the colonies of Sea squirts, (including the Baked bean ascidian - what a name!)  We watched as Lugworms pooed out their wiggly piles of sand as they created their U-shaped burrows.

Finally, let’s mention the Slipper limpet (see photo). These arrived accidentally in the nineteenth century from America in a shipment of oysters. They form stacks of up to 12 individuals. The largest and oldest are female with the younger, smaller males on top. If females die, the largest male will turn into a female.

Many thanks to Jenny for her leadership and arranging fantastic weather and to all attendees for their enthusiastic company.

For interest - Refer to David Bone’s “Bognor’s Rocks, a Geological Guide” and the websites of the ongoing Kelp Project and Solent Seagrass Project.

Gill Hance


 

Slipper Limpet