Lately I’ve been having some unintended success with producing large amounts of freshwater microalgae (it’s growing in the water bath which keeps my on-purpose plankton tanks warm) so I decided it was time to get some filter-feeding freshwater plankton to turn my green water into something useful.
Ever since I got these guys (the grown-ups are about 1/4″ or a bit less) I’ve been claiming to everyone that they’re ‘born pregnant.’ I’m still pretty sure that’s right, but wikipedia doesn’t back me up so I’d like to get some photographic evidence. The above shots are with my pocket camera — the following are with a kid’s digital microscope.
Puzzling! Not only are there not tiny pregnant daphnia inside the parent, but there aren’t even baby fleas in there at all — just blobs that look suspiciously like eggs. Either I’m completely misunderstanding how this life-cycle is supposed to work, or my daphnia have decided that my basement is about to suffer ice and/or drought and they’re making little bomb shelters to weather the coming cataclysm.
I will try to scoop out a few more expectant mothers tomorrow and see if everyone is in the egg business or if I just happened to scoop out the one long-term thinker.
Meanwhile, here are a few close-ups of one of the ostracods that have started reproducing like mad in an underpopulated shrimp tank. Another let-down: turns out that when multiplied 60x they just look like big pinto beans rather than tiny ones.