Microscopists’ weekend at Malham Tarn
Friday 3rd to Sunday 5th September 2021
By Paul Smith
The Malham Tarn Centre in the Yorkshire Dales was host to a short course on desmid identification, arranged by Martyn Kelly and open to members of the British Phycological Society and the Quekett Microscopical Club. There were around 20 twenty participants and experts.
I arrived mid afternoon, with the sky overcast, this did not brighten up until Sunday afternoon which made for a warm drive home!
Saturday morning was microscope setup and sampling. The sampling was done from the boardwalk, and I sampled Pond A. I also managed to drop my sample jar when trying to transfer the catch from the plankton net! Gently probing with stick located the jar, and I managed to retrieve it from a depth of about 12″; fortunately my wrist watch is waterproof to 100 m so was not stressed.
The sample was pretty turgid and was not all that productive. This was to change for Sunday after being allowed to stand overnight.
We were invited to bring anything of interest to the course and it happened that on Thursday evening I noticed a strange plant or filamentous algae in my aquarium. This was identified as Utricularia, a bladderwort, probably introduced to the aquarium with some new plants I had ordered from a plant breeder.
Utricularia sp. [by Paul Smith]
Sunday morning, back to the sample, I managed to find some desmids. First was a Cosmarium, there are several hundred species in the genus.
Cosmarium sp. [by Paul Smith]
Next was a Euastrum pinnatum, showing mother cell and nearly fully formed daughter cell.
Euastrum pinnatum [by Paul Smith]
Followed by a Closterium:
Closterium sp. [by Paul Smith]
And then the green Spirotaenia:
Spirotaenia sp. [by Paul Smith]
After the desmids were some girdle bands from Tabellaria diatoms:
Tabellaria girdle bands [by Paul Smith]
a large Stentor that appeared as a bean-shaped object which elongated into this.
Stentor sp. [by Paul Smith]
And, finally a rotifer I have not seen before, Rotaria, it appeared to have two sets of jaws! Looking closely, the set on the left is actually from a baby, these rotifers are live-bearing.
Rotaria sp. [by Paul Smith]
Joan Bingley also provided some photographs:
Ford at Goredale Beck [by Joan Bingley]
Sampling site at spring outflow [by Joan Bingley]
Sharing plankton trawl at outfall [by Joan Bingley]
Sampling from the boardwalk [by Joan Bingley]
Phragmites taking over [by Joan Bingley]
Report by Paul Smith, photographs by Joan Bingley and Paul Smith