> The only organisms that can actually pull this off are ones that can get by without oxygen: super simple bacteria and archaea. That means the entire natural w

> The only organisms that can actually pull this off are ones that can get by without oxygen: super simple bacteria and archaea. That means the entire natural world relies on a relatively small number of microscopic species to make nitrogen usable by more complex forms of life. I remember reading that this was a significant factor in why people were so alarmed over DDT. It had not been anticipated how widely it would spread beyond the places it was intentionally used and how it would persist. It ended up in almost all ecosystems, full of life it had never been tested on. If it had turned out to kill many of those small number of microscopic species that almost all plant and animal life relies on we could have been royally screwed. That obviously turned out not to be the case with DDT, but it made people realize that we had to be a lot more careful when designing and testing pesticides than we had been.