How does a pond change over a year n a couple of years?

Question

How does a pond change over a year n a couple of years?

Answer 1

The water in a pond is stagnant so all sorts of things keep falling on the surface like leaves, dust, etc.

When these start to decompose they change the color of the pond. Algae and spores also cause the change of colour to green.They can also cause the water to be brown , red water, and even black.