1 00:00:03,120 --> 00:00:08,080 Speaker 1: Welcome to brain Stuff, a production of I Heart Radio. Hey, 2 00:00:08,119 --> 00:00:12,920 Speaker 1: brain Stuff, Lauren Vogel bomb here. Everybody needs nitrogen, but 3 00:00:13,080 --> 00:00:17,360 Speaker 1: as far as non negotiable life sustaining elements go, it's tricky. 4 00:00:18,160 --> 00:00:22,400 Speaker 1: Living things require nitrogen for their cells to function. And furthermore, 5 00:00:22,560 --> 00:00:25,520 Speaker 1: we're virtually steeping in the stuff since our atmosphere is 6 00:00:25,520 --> 00:00:30,040 Speaker 1: made up of seventy percent nitrogen gas. However, there's a catch. 7 00:00:30,520 --> 00:00:33,000 Speaker 1: It's a water water everywhere, but not a drop to 8 00:00:33,080 --> 00:00:37,480 Speaker 1: drink kind of situation. Although nitrogen is floating basically everywhere, 9 00:00:37,720 --> 00:00:40,839 Speaker 1: it's not terribly abundant in the Earth's crust, and it's 10 00:00:40,880 --> 00:00:44,720 Speaker 1: incredibly difficult for living things to capture atmospheric nitrogen and 11 00:00:44,840 --> 00:00:47,800 Speaker 1: use it for their purposes. It's like having a bucket 12 00:00:47,840 --> 00:00:51,520 Speaker 1: full of Icelandic money and say Minneapolis, where you can't 13 00:00:51,560 --> 00:00:54,920 Speaker 1: spend it. And we spoke by email with Jesse Moates, 14 00:00:55,040 --> 00:00:57,720 Speaker 1: a PhD candidate at the Odum School of Ecology at 15 00:00:57,720 --> 00:01:01,640 Speaker 1: the University of Georgia. She said nitrogen is a major 16 00:01:01,720 --> 00:01:04,120 Speaker 1: part of amino acids, which are the building blocks of 17 00:01:04,120 --> 00:01:07,679 Speaker 1: proteins and nucleic acids such as DNA. In addition to 18 00:01:07,720 --> 00:01:11,080 Speaker 1: needing nitrogen for proteins and plants. It's a main component 19 00:01:11,120 --> 00:01:15,400 Speaker 1: of chlorophyll, which makes it crucial for photosynthesis. Since nitrogen 20 00:01:15,480 --> 00:01:18,440 Speaker 1: is a limited resource on this planet, a nitrogen atom 21 00:01:18,520 --> 00:01:20,959 Speaker 1: doesn't spend much time doing nothing when it's in a 22 00:01:21,040 --> 00:01:24,679 Speaker 1: form that living things can use. Scientists called nitrogen in 23 00:01:24,720 --> 00:01:28,360 Speaker 1: this form fixed. A fixed nitrogen is taken up by plants, 24 00:01:28,440 --> 00:01:31,280 Speaker 1: which are eaten by animals, which eat other animals, which 25 00:01:31,480 --> 00:01:34,959 Speaker 1: die and decompose and release nitrogen back into the ecosystem 26 00:01:35,080 --> 00:01:38,440 Speaker 1: to be worked on by bacteria or plants. And this 27 00:01:38,600 --> 00:01:41,240 Speaker 1: is the cycle of a nitrogen atom on Earth, and 28 00:01:41,280 --> 00:01:45,839 Speaker 1: its journey starts either very quietly or with a humongous bang. 29 00:01:46,600 --> 00:01:50,000 Speaker 1: The step one in the cycle is nitrogen fixation. Believe 30 00:01:50,000 --> 00:01:53,320 Speaker 1: it or not, Lightning and bacteria are the two things 31 00:01:53,400 --> 00:01:57,720 Speaker 1: primarily responsible for turning atmospheric nitrogen into nitrogen that living 32 00:01:57,720 --> 00:02:01,920 Speaker 1: things can use. Atmosphere nitrogen is very stable, so it 33 00:02:01,960 --> 00:02:04,360 Speaker 1: takes an incredible amount of energy to convert it to 34 00:02:04,400 --> 00:02:07,600 Speaker 1: a different form. If you've ever wondered why your outdoor 35 00:02:07,640 --> 00:02:10,680 Speaker 1: plants seem happier after a thunderstorm than they do when 36 00:02:10,720 --> 00:02:13,400 Speaker 1: you turn a sprinkler on them, there's a reason for that. 37 00:02:14,200 --> 00:02:18,680 Speaker 1: Lightning electrifies atmospheric nitrogen and water to reconfigure them into 38 00:02:18,680 --> 00:02:22,480 Speaker 1: ammonia and nitrates. This falls to the ground is rain, 39 00:02:22,639 --> 00:02:25,000 Speaker 1: where plants slurp it up and use it for their 40 00:02:25,040 --> 00:02:29,000 Speaker 1: biological processes. On the other end of the spectrum, the 41 00:02:29,040 --> 00:02:32,000 Speaker 1: most common way nitrogen is made available to organisms is 42 00:02:32,040 --> 00:02:35,760 Speaker 1: when atmospheric nitrogen is fixed by bacteria, and some of 43 00:02:35,800 --> 00:02:38,120 Speaker 1: which live free in the soil, and others of which 44 00:02:38,240 --> 00:02:43,400 Speaker 1: enjoy a symbiotic relationship with certain plant species. Lagoons like peas, clover, 45 00:02:43,520 --> 00:02:46,560 Speaker 1: and peanuts have little nodules on their roots that attract 46 00:02:46,600 --> 00:02:51,079 Speaker 1: bacteria that convert stubborn atmospheric nitrogen into ammonia or ammonium, 47 00:02:51,360 --> 00:02:54,680 Speaker 1: which can then be used to power the plant. Step too, 48 00:02:54,880 --> 00:02:58,679 Speaker 1: is nitrification. Ammonia in the soil can be used directly 49 00:02:58,720 --> 00:03:00,639 Speaker 1: by plants, but it's all so a step in the 50 00:03:00,639 --> 00:03:05,560 Speaker 1: process of nitrification, through which specialized bacteria and other microorganisms 51 00:03:05,600 --> 00:03:09,120 Speaker 1: convert ammonia into nitrite and then pass it off to 52 00:03:09,280 --> 00:03:12,440 Speaker 1: an entirely different set of micro organisms that further oxidize 53 00:03:12,480 --> 00:03:16,560 Speaker 1: the nitrate into nitrate. This process is slow, but it's 54 00:03:16,600 --> 00:03:18,760 Speaker 1: the way that nitrogen is built as a nutrient. In 55 00:03:18,840 --> 00:03:23,520 Speaker 1: soil and aquatic and marine environments. Terrestrial plants, for instance, 56 00:03:23,560 --> 00:03:27,160 Speaker 1: can absorb ammonium and nitrate through their root hairs. The 57 00:03:27,280 --> 00:03:30,960 Speaker 1: organisms that specialize in nitrification are also important in treating 58 00:03:31,000 --> 00:03:35,080 Speaker 1: municipal wastewater, and anyone who's kept an aquarium knows how 59 00:03:35,080 --> 00:03:38,400 Speaker 1: important those organisms are to keeping your water, fish and 60 00:03:38,560 --> 00:03:44,360 Speaker 1: plant friendly. Step three is a monification. Everything living eventually 61 00:03:44,400 --> 00:03:47,760 Speaker 1: dies and the nitrogen a particular organism was using when 62 00:03:47,760 --> 00:03:50,760 Speaker 1: it shuffled off. This mortal coil is taken to hand 63 00:03:50,880 --> 00:03:54,559 Speaker 1: by bacteria that turned the nitrogen rich corpse into ammonium, 64 00:03:54,720 --> 00:03:57,560 Speaker 1: which can be picked back up by plants and used again. 65 00:03:58,360 --> 00:04:02,280 Speaker 1: The step four is D nitrification. It's possible to convert 66 00:04:02,320 --> 00:04:06,760 Speaker 1: bioavailable nitrogen into atmospheric nitrogen again, and that process is 67 00:04:06,800 --> 00:04:12,119 Speaker 1: called unitrification. Nitrification is performed by bacteria and other microorganisms 68 00:04:12,120 --> 00:04:16,320 Speaker 1: that can tolerate oxygen. Not all microorganisms can. In the 69 00:04:16,360 --> 00:04:20,440 Speaker 1: case of D nitrification, certain anaerobic bacteria that don't need 70 00:04:20,520 --> 00:04:24,479 Speaker 1: oxygen convert nitrate to nitrogen gas, which floats up into 71 00:04:24,480 --> 00:04:27,320 Speaker 1: the atmosphere and plays hard to get again until some 72 00:04:27,520 --> 00:04:30,640 Speaker 1: lightning or crafty bacterium comes along and ropes it. Back 73 00:04:30,680 --> 00:04:33,239 Speaker 1: into the first step of the nitrogen cycle yet again. 74 00:04:38,560 --> 00:04:41,240 Speaker 1: Today's episode was written by Justesceline Shields and produced by 75 00:04:41,279 --> 00:04:43,440 Speaker 1: Tyler Klang. For more on this and lots of other 76 00:04:43,520 --> 00:04:46,800 Speaker 1: cyclical topics, visit how stuff works dot com. Brain Stuff 77 00:04:46,839 --> 00:04:49,240 Speaker 1: is production of by Heart Radio. Or more podcasts to 78 00:04:49,240 --> 00:04:52,240 Speaker 1: my heart radio, visit the iHeart Radio app, Apple Podcasts, 79 00:04:52,320 --> 00:04:54,120 Speaker 1: or wherever you listen to your favorite shows.