Tag Archives: Pond

Conservation, Natural History

Pond-Skimming Reveals Hornwort, Newts, Pondweed, Water Scorpion, Leeches

Pond-skimming. Netty is rescuing pondweed and animals especially damselfly nymphs to return them to the water.

We spent the time skimming off as much of the duckweed that was blanketing the surface of the pond as possible using pole nets. The idea is to let light filter down to the bottom of the pond to encourage the more delicate pondweeds. In the process, we had a good opportunity to check the status of some of the pond life that we don’t usually get to see, as the underwater plants are rather few beside the boardwalk – most likely because the continual sampling keeps them from growing much. But the rest of the pond is another story.

Rigid Hornwort, its shoots stiff as if covered in limescale
Canadian pondweed
Damselfly nymph with leaflike tail appendages
A stubby damselfly nymph with spiky tail appendages

There were at least two kinds of damselfly nymph, possibly bluetail and azure damselflies, judging by a pondside look at the book without a handlens. The little camera in close-up mode is just about capable of resolving detail at this scale, given good light. The various damselfly nymphs have differently-shaped tail appendages, which the book says are diagnostic.

Leaflike tail appendages of a long slender damselfly nymph, with feathery venation just about visible: I must have a look with the microscope and book!

We also caught a newt or two. We carefully put all the minibeasts and interesting bits of pondweed back in the water.

Hoglouse
Leech on finger 1
Leech on finger 2
A fine big Water Scorpion
Environment, Wetlands

Blanket-weed Sprouting in January

Blanket-weed (Spirogyra) covering pond in January
Blanket-weed (Spirogyra) covering pond in January

We’re all getting used to the local effects of global warming − garden crocuses and primulas coming up earlier and earlier (they’re flowering already in my garden).

This past fortnight I’ve realized that my efforts to earth up the rhubarb to protect it from frost weren’t working, as frost or no it was cheerfully and energetically pushing up new leaves on long thin red petioles, the leaf-stalks that greengrocers see as  rhubarb.

But I’ve never seen a pond growing over with blanket-weed in January before. Generally it’s an effect seen late in summer, the tangled green mat forming in a rather nutrient-rich (eutrophicated) lowland pond. Each green thread is a flexible cylinder consisting of a single row of plant cells inside their thick cellulose cell walls, with amazingly elegant green spiral chloroplasts inside, hence the apposite and beautiful name of the genus, Spirogyra, drawn and carefully labelled in millions of high school biology exercise books. The strands grow like crazy in warm ponds and ditches, benefiting from the excess of nutrients from runoff in agricultural areas or indeed from towns. The blanket can blot out light from the deeper parts of a pond, killing other organisms living there. But warm enough for blanket-weed in January? That’s something new.