Human activities, such as making fertilizers and burning fossil fuels, have significantly altered the amount of fixed nitrogen in the Earth's ... thus impacting more processes than just the ...

Imagine if Earth's history ... Carbon and argon are far more abundant relative to nitrogen than in the meteorites that likely delivered these elements. Scientists have proposed many hypotheses ...

The fifth-most abundant gas in the universe, the most pervasive on earth, there is roughly three times more nitrogen in the air than oxygen ... millennium, human population has generally been ...