21. Some plants have coevolved with nitrogen fixing bacteria, making plants an important part of the nitrogen cycle . 22. "Nitrobacter " plays an important role in the nitrogen cycle by oxidizing nitrite into nitrate in soil. 23. These organisms play a crucial role in benthic ecosystems, forming essential food chains and participating in the nitrogen cycle . 24. They are important in the nitrogen cycle by increasing the availability of nitrogen to plants while limiting carbon dioxide fixation. 25. Abundance of microbial genes associated with nitrogen cycling as indices of biogeochemical process rates across a vegetation gradient in Alaska. 26. Nitrous oxide, N 2 O, is a natural part of the nitrogen cycle , but human land uses often add more. 27. The focus of his research is on elucidating the molecular microbial ecology and metabolic pathways of the microbial nitrogen cycle . 28. Three planetary thresholds have already been crossed, including 1 ) biodiversity loss, 2 ) climate change, and 3 ) nitrogen cycles . 29. Horseshoe vetch notwithstanding, bacteria play a crucial role in the nitrogen cycle and in many other processes that help sustain life. 30. In the marine environment, nitrogen is often the limiting nutrient, so the nitrogen cycle in the ocean is of particular interest.
