Sep 20-26, 2008
This was from Chestermere Lake, where leaves and weeds had begun washing against a sandy bank. Among the debris there were some cloud-shaped Ophrydium colonies, with many more floating or on submerged plants further out, as well as some amphipods and insects. Both plant material and sand were taken, with two small leeches and a ramshorn snail emerging once these had settled.
Many cyclopoids were active around the top of the sample. The debris and sand contained a variety of pennate diatoms, including some Fragilaria and Asterionella, along with frequent Merismopedia sheets. There were also clumps of Zygnema and other filaments including Spirogyra, Mougeotia, and some thicker green algae.
Here and there vorticellids were attached to the debris, sometimes accompanied by Stentor and bdelloids. Many other types of ciliates were also found, notably long Spirostomum and colepids. There were also red flagellates scattered among the plant material, sometimes with small euglenoids and colourless kinds.
A portion of an Ophrydium colony was also taken but after a few days it lost cohesion; the cells died while needle-like diatoms inside it increased. With this the water changed in smell and innumerable colourless Cryptomonas appeared, along with more colepids. Other animals and ciliates seemed less affected.
↬ Thanks to Michael Plewka, author of plingfactory: life in water, for the identification of Cephalodella and to phycologist Roman Romaov for the identification of Hyalotheca dissiliens and Craticula.
Ciliophora - about 110 µm
Ciliophora - about 285 µm
Spirotrichea - about 50 µm
Spirotrichea - about 135 µm
Spirotrichea - about 75 µm
Vorticellidae - body about 65 µm
Vorticellidae - body about 100 µm