Water sample collected at river Conchos, Julimes, Chihuahua, on December 5th at the indicated location and time.
The images were acquired on December 8th.
A Lake water sample (freshwater) was taken on 11/06/2021 using a 10 micron dip net to enrich for microorganisms.
Mag. 400x
Very small heliozoan (~10µ diamter). Actinophrys does have marine members, but I don't know how small they are. Another possibility is Ciliophrys, a small marine actinophrid heliozoan, https://www.arcella.nl/ciliophrys-infusionum/ and https://www.researchgate.net/publication/296882090_Taxonomy_and_Phylogeny_of_Heliozoa_III_Actinophryids.
From one of the main tidal channels of the salt marsh, a water sample was taken on 11/10/2021 using a 10 micron dip net to enrich for microorganisms.
Continued observation of a sample collected 20210314 from a river tributary, scoop of sediment near the bank.
Three different shells.
Genus Hyalosphenia?
Flagellum was slightly visible at times but did not show up in this image.
Collected in fresh water.
About 45µm in diameter. Last image (gif) shows flagella in slow motion.
ID for smaller green sp. that comes in from the left.
GIF image
From water in roadside ditch, lined with various mosses and liverworts. 400x magnification.
This is for the bottom filament, not the Spirogyra. Very numerous filamentous alga in a small freshwater pond
Ciliate found in a diatom film at the bottom of a freshwater stream. Attempting to 'swallow' one of the diatoms, but it escaped.