London Rivers Week
Saturday 31st May 2025
London Rivers Week is an annual collection of events organised by Thames21. As part of our outreach programme, this year we took our microscopes to the event in the new wetland area in Chinbrook Meadows. The Friends of Chinbrook Meadows organised a family-friendly event with a picnic, pond-dipping, a talk about the wetlands project, and meditation. We were pleased to have a steady stream of visitors all afternoon.
The sequence of four ponds in the wetlands area has been designed to improve the water quality in the River Quaggy, which flows through the Meadows. With help from ZSL, local volunteers have been monitoring the water quality through invertebrate sampling and testing phosphate and ammonia levels, comparing the results between the first and fourth ponds. Last year, volunteers planted thousands of plants in and around the ponds, and many of them have survived and seeded.
Wild flowers around the ponds
To collect specimens from the ponds, Nigel Ashby used a plankton net attached to a Leeda R2062 Power Landing Handle that extends to 3.1 metres.
Nigel Ashby collecting
Nigel Ashby collecting
There was a lot of duckweed (Lemna minor) on the surface of the ponds, but not much blanket weed yet.
Lisa and Nigel Ashby brought a small stereomicroscope, several magnifiers, some trays, jars and dishes, some of the Quekett’s free leaflets, and Water Animal Identification Keys by J. Eric Marson. Alan Wood brought a small stereomicroscope, his Olympus SZ045 stereomicroscope with an LED ring-light running from a powerbank, and a copy of Collins Field Guide to Freshwater Life (the 1986 edition by R. Fitter & R. Manuel, very popular with Quekett members).
Lisa Ashby (left) with visitors
Visitors with our microscopes
Nigel and Lisa Ashby with the low table
Samples in a white tray
We used pipettes and plastic teaspoons to transfer specimens from the tray to small Petri dishes and cavity slides.
Samples in small (35 mm) Petri dishes
The specimens that we found included waterfleas (Daphnia ?), copepods, a caseless caddis larva, water lice (Asellus aquaticus), some tiny water scorpions (Nepa cinerea), water-boatmen (Notonectidae), lesser water-boatmen (Corixidae), beetle larvae, fly larvae (including bloodworms), a small dragonfly nymph, a mosquito pupa, leeches, pond snails (Limnaeidae) and ramshorn snails (Planorbidae). The specimens were returned to the pond.
There were dragonflies and damsel flies flying over the ponds and the surrounding plants, as well as a few butterflies.
Some of the free Quekett leaflets
We didn’t only look at pond life. Other specimens that we collected for the microscopes included an ox-eye daisy flower (Leucanthemum vulgare), stems and leaves of cleavers (Galium aparine), and flower spikes of wall barley (Hordeum murinum). One youngster brought a ladybird larvae to examine.
Wall barley spike (left) and its barbed awns (hairs) under a microscope
(the awns are about 0.2 mm diameter)
Cleavers (left) and its hooked leaf hairs under a microscope
(the hooked hairs are about 0.13 mm long)
Ladybird larva (9 mm long)
The Friends kindly provided two tables for us, as well as two for their own use with several white trays, laminated copies of the WildID Freshwater name trail, buckets and pond nets for collecting specimens, pipettes, turkey basters and plastic teaspoons for selecting specimens, and magnifiers for examining them.
Trays with specimens
Victoria Morris with visitors (Maggie Leharne at right)
Anne Slater talking about the wetlands
Victoria Morris did not just collect and show specimens from the ponds, she also made some sketches.
Sketch by Victoria Morris
(including Nigel Ashby with his net and Alan Wood with his camera)
Report and most photographs by Alan Wood