Creatures living in a dirty pond

Dirty pond?  It looks dirty but that's from human's perspective but it might be the most healthy environment for the organisms living there.  During the summer, the pond is full of living creatures that feeds on microorganisms whose population is exploding owing to the warm weather.  Summer should be the season for the celebration of life.  I found the pond of the nearby Brisco park is full of green algae. The density and varieties of the creatures living in the water is amazing.

I took couple drops of water from the top of the collection tube and drop them in a concave slide.  The water is very concentrated with colonies of Volvox - a very popular green algae as model organism for research.  Rotifers are also abundent in the collection.

A colony of Volvox.  Therea re hundreds of cellls per colony.  I found most Volvox images on the Internet are spherical but most colonies I observed are somewhat irregular.  I suspected the the shape of the Volvox colony is distroyed by the predatory rotifer, Euchlanis.

a Rotifer (Euchlanis sp.) is swimming in the matrix of Volvox colony. 

A group of stentors are feeding.  Some green algea colonies are apparently ingested by the stentors.

A flatworm is gliding through green algae matrix

a seed shrimp (Ostracod)

Water mite.

A Desmid (Microasterias sp.)

Cosmarium sp.

On the top is spirogyra and bottom is an unidentified diatom

Scenedesmus sp.

On the left is the Pediastrum, on the right is a Staurastrum.

Of course, on the top of those microorganisms and microscopic animals (such as rotifers, copepods and seed shrimps) in the food chain are those with bigger mouth.  I found plenty of tadpoles in the pond.  Fueled by the warm and sunny weather, the green algea populations are booming.  On top of this is the faster nutrient break down and growth of the microsorganisms. The predatory protozoa and microscopic animals has plenty to feed on.  All the energy is feeding toward to top of the food chain. I have no surprise to find that many tadpols in the pond.

How about those canadian geese?  They've flown thousands of miles to have the feast!