Why does Salt kill bacteria?

[Cookie]

My science project is about how salt affect micro-organism. Basically, to test my experiment I added Sodium Chloride in a 100ml of pond water and see how the micro-organisms reacted. The more salt I put the more micro-organisms die; now I need to know what causes them die.

Any help is greatly appreciated
Thank you!!

I've looked over my bio book and done a small research on my own; does it have to do with osmosis?

[MelissaB]

It does have to do with osmosis, yes. You might also want to look up 'homeostasis' and 'dessication'. Basically, if you increase the concentration of salt outside a bacterium, the water in the bacterium will move out into the surrounding water to equalize the concentration. At that point, the bacterium can no longer maintain structural integrity, because it needs to maintain homeostasis.

Hope that helps!