Pond
Yes, pond is a common noun (If the pond had a name, it would proper).
Without vegetation, pond water would be almost pure. A lack of vegetation would cause pond animals to leave and therefore would alter the life systems of the pond. Eventually, algae and reeds would grow in and around the pond, regardless if animals are there or not.
The best kind of pond pump for a two hundred gallon koi pond is an alpine pond pump. This would work best for this size pond because of it's size and power.
The word pond would become obsolete.
Yes, pond is a common noun (If the pond had a name, it would proper).
You would have to be in Massachusetts to visit Walden Pond, which is located in Concord.
Classification of natural species is pretty confusing and sometimes arbitrary. The rules originally used have in some cases been shown to overlap and refute themselves. Also, the term pond scum, can be ambiguous. Sometimes cyanobacteria are called pond scum. They belong to the Kingdom Monera. Other times you may have different types of algae called pond scum, those are indeed classified as protists. So I would say that some kinds of pond scum are protists, and some are bacteria.
that depends on a lot of things, for example how large you would your pond to be.
It depends on the pond, since they are not a standard size.
A pond pump helps circulate the water properly. If it is not used, the water would sit still and get slimy. If there are fish in the pond it would help keep the water clean.
Yes, shrimp eat pond weeds. The crustacean in question generally gets classified as an omnivore ("everything-eater") and therefore may sample pond animals and plants during meal times.