Green algae and diatoms
- a ciliated protozoan 200X magnification These microscopic, single-celled organisms (they are not "bugs" or animals!) are fun to observe through a microscope. Vorticella are stalked, ciliated protozoa. The bell-shaped part of the cell has a ring of cilia, tiny hairlike structures that wave back and forth to pull in any edible particles in the water. When the cells are stimulated in a negative manner (like when I put them under a projection microscope with a hot, bright light!) the stalk coils like a spring, they spin and pull down toward the substrate to which they are attached. They appear to bounce or pop up and down. The thin, thread-like stalks are just barely visible on some of the cells in this photo. A Vorticella spins around like a vortex or small tornado, probably the origin of the "vorti" part of its name. These cells are attached to a green alga strand. I often see the attached to leaflets of Milfoil and even small aquatic snail shells.
spp. / Order: Cladocera This tiny, transparent, freshwater creature was photographed with a projection microscope, the image is projected on the tabletop onto a piece of white paper. These animals can be pinpoint-sized to the size of a pinhead. They are very common in freshwater lakes and ponds, in fact, if you have ever been swimming or water skiing in a lake, you've probably swallowed a few of them! The large black spot on the head is a compound eye and the long brown strip in the middle is the digestive system. I enjoy telling my students about the reproductive cycle of water fleas. Most of the year the animals are all females. They reproduce by cloning themselves, no males needed! The olive-green oval in this waterflea's brood pouch is her developing clone. When conditions get stressful in the habitat, males can be produced; when a male and female mate, a resting egg develops. The egg is released and settles to the bottom of the lake or pond, when conditions improve, the young water flea will hatch. Water fleas are the aquatic equalivalent of the "canary in the coal mine". Water treatment plants often use water fleas to test the quality of water before returning it to the river.
