How many grams of salt must be added before microorganisms die?

Question

Im doing this science project and its due today?
Here is the origional Question. If you incrementaly add table salt (sodium chloride) to a solution of microorganisms (such as pond water) How many grams of salt must be added before microorganisms die.

Answer 1

Depends on the sensitivity to salt of the organisms, as there are some organisms that thrive in high salt environments, and others that die in an environment with even as little as a nanogram of salt present.
But, on average, enough salt to make the water float a raw egg, will kill most, if not all, organisms present.

Answer 2

It depends on the microorganisms.

Some die in sea water, some die in a great deal more concentrated solutions, and some simply form themselves into cysts or spores (Bacillus bacteria will do so, for instance) and never be killed.

Being more specific as to which microbes would be very handy.

Answer 3

They never do ! Microbes simply switch themselves off or form cysts when they encounter inhospitable conditions like high salinity. When conditions return to normal they again start reproducing.

Also there are some microbes which also exist in highly saline environments like the Dead Sea.

Answer 4

29