Check out Martyn Kelly’s blog post about Volvox from a pond in England:

The annual Algal Training Course in Durham always has a field trip out to Cassop Pond, a small pond at the foot of the Permian Limestone escarpment in County Durham that has featured in a few of my posts over the years (see “A return to Cassop”).  This year, the group came back with some samples from the pond’s margins bearing a suspension of green dots just visible to the naked eye which, when examined under the microscope, turned out to be the colonial green alga Volvox aureus.

There’s more, including some lovely micrographs, at https://microscopesandmonsters.wordpress.com/2019/07/17/the-intricate-life-of-a-colonial-alga/.