Nitrification: What is the real impact on our planet

Nutrification. Nitrfification. I have seen it spelled twice. No not added food product's. The other one. This subject was brought up to me by a buddy. He claimed his sister was a scientist from some big University and that the real danger to earth was this new whizzo lab coat word. Nitrification.
Yup so here is the amount of data I can produce about it. I will finish with what his story as told by his sister to him (yawn super hearsay at best) but I did find some things over the internet.

Some strage document I found
That is childish at best but my Gunny always told me to KISS it. Keep It simple STUPID!
so i like it

Link To Definition Yea so I dont really know about this site, but at least it has basic references.

Here is a little better written summary of a Coastal Reef and the effects down in Brasail.

Now Wiki states "Nitrification is the biological oxidation of ammonia with oxygen into nitrite followed by the oxidation of these nitrites into nitrates. Degradation of ammonia to nitrite is usually the rate limiting step of nitrification. Nitrification is an important step in the nitrogen cycle in soil. This process was discovered by the Russian microbiologist, Sergei Winogradsky."
WIKI

So anyway, his sister uses all vinegar to clean everything, and she thinks we are allready past bad and need to reduce population. Well thats the hear-say and I dont know if it's really that bad or can it be reversed?

Thanks for your time