How does andrew knoll's idea that "prokaryotic metabolisms form the fundamental ecological circuitry of life; bacteria, not mammals, underpin the efficient and long-term functioning of the biosphere" relate to the nitrogen cycle?

Andrew Knoll's idea about prokaryotic metabolism from fundamental ecological circuity of life the bacteria but not the mammals, underpin the long-term and efficient functioning of the biosphere, it relates to the nitrogen cycle because of the bacteria is not emitting any nitrogen at all.