The easing of lockdown means that fieldwork can resume (real fieldwork, that is, rather than virtual perambulations around the margins of Lough Down) and I was in the Lake District last week collecting samples for an ongoing project. The New Normal means a rethink of logistics to account for social distancing which, in my case, meant Heather taking the place of Ben as BenthoTorch wielder so that we could safely share a single car.
Our travels took us to the River Calder, a short river that rises on the western fells of the Lake District, just south of Ennerdale Water, and flows about 12 kilometres to join the Irish Sea at Sellafield (it actually flows through the BNFL site and those with a long memory may remember that the first incarnation of the nuclear reprocessing site was known as “Calder Hall”). This is one of a number of rivers of this name in the UK, with an ancient Celtic root referring either to the violence of the flow or the stony nature of the bed. The two roots are linked: a harsh hydrology will flush away all but the largest and roughest stones and, as the photograph above shows, the bed of the Calder has plenty of these.
When not photographing me peering at stream beds through a bathyscope, Heather noticed some bright yellow growths on the floor of the forest surrounding the stream which she recognised as a slime mold with the rather unappetisiing name of dog’s vomit. For once, the Latin name, Fuligo septica, sounds more appealing. Under the microscope, all I saw were spherical spores but these will germinate and the cells will aggregate to form an amoeboid-like mass that moves around searching for nutrients. YouTube has some fascinating videos that shows this happening.
Fuligo septica – dog’s vomit slime mold – photographed in woodland beside the River Calder, Cumbria, June 2020 (photograph: Heather Kelly)
Slime molds interest me for another reason today: they are a group that has bounced around the tree of life in the years since I started my career. When I was at school, slime molds were dealt with cursorily as one group within the fungi which, in those far-off days, were considered to be part of the plant kingdom. In the far past, algae and fungi were grouped together as the “Thallophyta”. This particular slime mold still sits in a class called the Myxomycota (literally “slime fungi”) which alludes to this heritage. Now, the idea of fungi being relatives of the plants is quite laughable: they differ in so many ways, not least the completely different form of the cell wall and the absence of photosynthesis. The fungi are treated as a separate kingdom but the slime molds have undergone one further divorce. No longer are they considered to be a group within the fungi, rather they have all been shifted to the Protozoa, itself also a separate kingdom. The slime molds do, superficially, resemble some fungi in some respects but, in others, they are completely different. This fragmentation from the straightforward view of biological classification of the past, resembles that which has occurred in the algae: once considered primitive “plants” but now spread between four kingdoms. The Euglenophyceae, which have appeared in this blog on a couple of occasions (see “A visit to Loughrigg Fell” and “Puzzling puddles on the Pennine Way”), are, in fact, more closely related to dog’s vomit slime mold than they are to any other group of algae.
Microscopic view of cells of Fuligo septica, dog’s vomit slime mold. Scale bar: 10 micrometres (= 100th of a millimetre).
The slime molds are not the only group that used to be classified as fungi but which are now more closely allied to algae. Potato blight (Phytophora infestans) belongs to the Oomycota (or “egg-fungi”, due to their large oogonia). This group is now classified in the same kingdom (Chromista) and phylum (Heterokontophyta) as several groups of algae including the diatoms and brown seaweeds. It is a fairly distant relationship in the grand scheme of things (equivalent to comparing yourself to a sea squirt) but it still means that I make my living from relatives of the organism that drove my ancestors to leave Ireland.
Some other highlights from this week:
Wrote this whilst listening to: old Glastonbury sets on the BBC iPlayer, particularly from 2009 and 2010, when I was there. Notably Blur’s headline set (watch out for the crowd surfer who disappears from view halfway through Song 2. I was directly underneath. Also Dizzee Rascal from 2010 and highlights from Bruce Springsteen’s 2009 set. And Radiohead from 1997.
Cultural highlights: The new interpretations of Alan Bennett’s Talking Heads, produced by Nicholas Hytner on BBC2. ]
Currently reading: Lethal White by Robert Galbraith (aka J.K. Rowling).
Culinary highlight: French onion ramen, a French/Japanese fusion from Tim Anderson’s Vegan Japaneasy.