Matthew writes:
“My tattoo is taken from a 1950’s biology textbook. The reason it means so much to me is because of the relevence of the nitrogen cycle to the cycle of life. The horse dies, which feeds the plant, which feeds the horse. Its really quite beautiful.”Carl writes: We are each fleeting intersections of the Earth’s biogeochemical cycles, the paths of nitrogen, carbon, oxygen, and the other elements. The carbon cycle is the most familiar of those cycles today, because we are adjusting its knobs so that more carbon is shooting into the atmosphere than was the case before the Industrial Revolution, trapping heat from the sun. If we were to shut the knob off, atmospheric carbon would slowly subside over hundreds of thousands of years as it flowed further on through the carbon cycle, to the bottom of the ocean and ultimately into the bowels of the Earth.
The nitrogen cycle is important as well, and we are also adjusting its knobs. Today the nitrogen entering the world’s soil is moving at twice its natural rate, thanks to our production of fertilizers and burning of fossil fuels. The nitrogen that gets into streams flows out to the oceans where it triggers runaway explosions of microbes, leading to oxygen-free “dead zones” in places like the Baltic Sea and the Gulf of Mexico. These dead zones would be far bigger if not for the help we get from a hidden part of the nitrogren cycle–bacteria in the soil and banks of streams and rivers. Some of these microbes have the biochemical wherewithal to pull nitrogen out of the water and turn it into molecular nitrogen or nitrous oxygen (N20), which diffuses into the air. But these bacteria cannot turn the knobs all the way back; the more nitrogen they are given, the less efficient they get at converting it. As the world’s population grows and releases more nitrogen, the hidden parts of its cycle may come painfully to light.
Go Further
Animals
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- Why this rhino-zebra friendship makes perfect senseWhy this rhino-zebra friendship makes perfect sense
- When did bioluminescence evolve? It’s older than we thought.When did bioluminescence evolve? It’s older than we thought.
- Soy, skim … spider. Are any of these technically milk?Soy, skim … spider. Are any of these technically milk?
- This pristine piece of the Amazon shows nature’s resilienceThis pristine piece of the Amazon shows nature’s resilience
Environment
- This pristine piece of the Amazon shows nature’s resilienceThis pristine piece of the Amazon shows nature’s resilience
- Listen to 30 years of climate change transformed into haunting musicListen to 30 years of climate change transformed into haunting music
- This ancient society tried to stop El Niño—with child sacrificeThis ancient society tried to stop El Niño—with child sacrifice
- U.S. plans to clean its drinking water. What does that mean?U.S. plans to clean its drinking water. What does that mean?
History & Culture
- Meet the original members of the tortured poets departmentMeet the original members of the tortured poets department
- Séances at the White House? Why these first ladies turned to the occultSéances at the White House? Why these first ladies turned to the occult
- Gambling is everywhere now. When is that a problem?Gambling is everywhere now. When is that a problem?
- Beauty is pain—at least it was in 17th-century SpainBeauty is pain—at least it was in 17th-century Spain
- The real spies who inspired ‘The Ministry of Ungentlemanly Warfare’The real spies who inspired ‘The Ministry of Ungentlemanly Warfare’
Science
- Here's how astronomers found one of the rarest phenomenons in spaceHere's how astronomers found one of the rarest phenomenons in space
- Not an extrovert or introvert? There’s a word for that.Not an extrovert or introvert? There’s a word for that.
- NASA has a plan to clean up space junk—but is going green enough?NASA has a plan to clean up space junk—but is going green enough?
- Soy, skim … spider. Are any of these technically milk?Soy, skim … spider. Are any of these technically milk?
- Can aspirin help protect against colorectal cancers?Can aspirin help protect against colorectal cancers?
Travel
- What it's like to hike the Camino del Mayab in MexicoWhat it's like to hike the Camino del Mayab in Mexico
- Is this small English town Yorkshire's culinary capital?Is this small English town Yorkshire's culinary capital?
- This chef is taking Indian cuisine in a bold new directionThis chef is taking Indian cuisine in a bold new direction
- Follow in the footsteps of Robin Hood in Sherwood ForestFollow in the footsteps of Robin Hood in Sherwood Forest