I embarked on a pilgrimage, of sorts, last weekend, driving to the Druridge Bay, on the Northumberland coast, about 30 kilometres north of Newcastle. On a sunny day, this is a wonderful horseshoe-shaped expanse of wide, and often almost empty, beach backed by sand dunes and facing into the North Sea. It was, however, unseasonably wet and windy during my visit, which robbed it of much of its charm.
Druridge Bay at low tide on a wet Saturday afternoon in May 2013.
I was following in the footsteps of Arthur Scott Donkin, lecturer in Medical Jurisprudence at King’s College, University of Durham in the middle of the nineteenth century. King’s College was the medical school attached to Durham though it was in Newcastle, rather than in Durham itself. It eventually broke away from Durham to become the independent University of Newcastle, where I currently teach. Details of Donkin’s professional life are vague but would have involved the application of medicine knowledge in legal fields. This predates the establishment of forensic science as a distinct discipline (the first Sherlock Holmes story did not appear until 1887) so perhaps his main interests were pathology and autopsies?
Donkin’s hobby, and his legacy, was microscopy, and he published about half a dozen papers describing the diatoms of north-east England and we know that Druridge Bay was one of his favourite collecting grounds. There is one very common diatom, Navicula gregaria, whose original description was based on material collected by Donkin from here, and another, less common diatom which is actually named after Druridge Bay. It was a curiosity to see this diatom that had brought me here at low tide.
I scooped up enough wet sand to fill a mussel shell, put this into a large plastic bottle. added about 250 millilitres of seawater and screwed on the top. I then shook the bottle hard for about two minutes then allowed a few seconds for the sand to sink to the bottom before pouring the now-cloudy seawater into a smaller bottle. Back at home, I stood this bottle in the fridge overnight to allow the particles to settle, poured off the clear water and siphoned up a few drops of the settled material to examine under my microscope.
I went through this rigmarole in an effort to dislodge some of the algae that live attached to the sand grains, as it was here that I hoped to find some cells of Druridgia compressa, the species that Donkin had described back in 1861. However, I seemed to be out of luck, finding mostly just particles of organic matter of indeterminate origin until one lone diatom cell glided into view. By coincidence, this was a diatom belonging to a genus called Donkinia – named after Arthur Scott Donkin by one of his fellow microscopists. This was not growing on the sand grains but, instead, moves through the gaps between grains.
A cell of Donkinia collected from Druridge Bay in May 2013. It is about 50 micrometres (1/20th of a millimetre) long.
Druridgia reminds me of a line from Henry IV part I that I was forced to learn at school: “… Being wanted, he may be more wondered at ….” One of my books describes Druridgia as being “rarely recorded”. Apply this criterion to a bird or a higher plant and it would become a cause célèbre for the conservation movement. Yet Druridgia is a microscopic alga, so is unlikely to elicit the same level of attention even though it represents an evolutionary lineage as long and as fascinating as those of the more charismatic creatures that fill our television screens.