The low efficiency of ammonium fertilizers used in agriculture contributes to significant environmental issues and economic losses. This Review discusses the chemistry and enzymatic mechanisms of microbial nitrification in the soil and highlights phytochemicals which can act as nitrification inhibitors, thus providing opportunities to stabilize ammonium in farm soils to increase the efficiency of nitrogen use.
Abstract
Approximately two percent of the world's energy is consumed in the production of ammonia from hydrogen and nitrogen gas. Ammonia is used as a fertilizer ingredient for agriculture and distributed in the environment on an enormous scale to promote crop growth in intensive farming. Only 30–50 % of the nitrogen applied is assimilated by crop plants; the remaining 50–70 % goes into biological processes such as nitrification by microbial metabolism in the soil. This leads to an imbalance in the global nitrogen cycle and higher nitrous oxide emissions (a potent and significant greenhouse gas) as well as contamination of ground and surface waters by nitrate from the nitrogen‐fertilized farmland. This Review gives a critical overview of the current knowledge of soil microbes involved in the chemistry of ammonia nitrification, the structures and mechanisms of the enzymes involved, and phytochemicals capable of inhibiting ammonia nitrification.
https://ift.tt/2Gw05qI
I posted a map recently and someone said my planet was too Earth-like. Well, challenge accepted. I'm considering ammonia-based respiration (nitrification) in a reasonably ammonia-rich atmosphere. I know little about biochemistry though. Prepare for a barrage of questions (sorry).
I'm pretty much basing everything on what's written here.
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Ammonia is not very dense. Would it all just escape higher up into the atmosphere, except where dissolved in rivers, lakes and seas? Will a slightly higher gravity help at all by pulling the atmosphere in or will there just be more collected material in the atmosphere?
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I'm looking at using SH2 (hydrogen sulphide) as a reducing agent. Therefore, there should be sulphur ions produced assuming the hydrogen is taken by the oxygen. I'm assuming this sulphur would then react with oxygen to produce SO2. This releases quite a lot of energy, reacting explosively in air, according to wikipedia. Would this still be dangerous if diluted? Could it cause harm? Is there even a way the energy release could be harnessed?
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Would I be right to assume the reaction can be reversed with some external energy input, photosynthesis style? Would the strong bonds in SO2 pose an issue here? Would photosynthesis reverse both steps in one go?
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Strangely, ammonia is an inhibitor of nitrification, apparently, as is nitric acid which may be produced. Would this affect the viability of its widespread use? The world I'm 'building' is a little warmer than Earth by 30o C or so, which means metabolisms will be a bit higher. Will this help to much of an extent?
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What happens to the nitrate and hydrogen ion produced? Is the hydrogen 'used up' in ATP production (or equivalent - I'll cross that bridge when I get to it some other time)? Or is nitric acid formed? Would it remain dissolved and dilute until excreted/removed without causing problems or would there be acidity-based repercussions?
Does anyone have favorite references to read up on the nitty gritty of Nitrification for wastewater treatment?
I work at an HPO plant without any requirements for nutrient removal. We operate with a low SRT (~1.5 days) to avoid Nitrification. As a result we have a very high F/M ratio. I don't understand why we have Nitrification at such a low SRT when conventional activated sludge has no issues at much longer SRTs. What other factors come into play here?
Weird situation right now reefers, there's a question I'd like to get some theories on. So I added a frozen shrimp into my week old tank stocked with live rock and sand 1lb/gallon yesterday morning, and this morning I checked my levels. Huge ammonia spike, my readings were at 4.0 ppm and now, about 6 hours later I check again and it's reading 0 ppm. Now before I go to bed I decided to check one last time and it's back up to 0.5 ppm. Is the cycle supposed to fluctuate this much? And the really weird thing is that there isn't a speck of nitrite or nitrate to be found either! It's like the ammonia shows up and disappears and reappears in varying levels. I know the tank is cycling because of all the live material and the fact there is some light diatoms in the front left corner. I'm just wondering if anyone could settle my nerves and tell me what's going on?
Hi. I'm currently doing a project, describing some field-study data from a temperate meadow. Background for quesiton. The soil gas samples acquired from the field-study indicate that there are a large N2O "hotspot" emission related to microbial processes in the soil. I can identify them by potential assays and site preference values (gas samples analyzed for 15N etc - point is that the N2O emission could be attributed to autotrophic nitrification).
I thought ok, N2O can be produced from soil microbial processes of denitrification, nitrification and others. When I finally went to write to part about the N2O produced by nitrification (quite a large amount relative to an unfertilized grassland). The part that got me stumped was, in several articles as well as textbooks, they depict nitrification as as either the oxidation of ammonium (NH4+) to nitrite (NO2-) to nitrate (NO3-) - autotrophic nitrification or ammonia-odixation ammonia (NH3) to NH2OH to nitrate (NO2-) - heterotrophic nitrification.
N2O can be produced by incomplete oxidation of NH2OH in heterotrophic nitrification, aerobic denitrification (nitrifier denitrification), as well as autotrophic nitrification, where N2O and NO can "leak" between the NO2- and NO3- oxidation.
But textbooks or articles doesn't depict how this is leaked or how it is produced, other than the vague indication of it being emitted during the autotrophic nitrification under certain conditions. I know that the N2O gas samples collected can be attributed to autotrophic nitrification and not denitrification/aerobic denitrification (nitrifier denitrification), but it puzzles me how the amount of N2O produced (rates comparable to fertilized agricultural fields) can be attributed to autotrophic nitrification when everyone is so vague about how the N2O is produced from the specific oxidation. Especially since all the N2O emission from the soil could 100% be attributed to autotrophic nitrification and none of the other microbial processes producing N2O. All other processes are very throughly depicted on the intermediates, but usually just represented in the autotrophic nitrification as a bubble next to the reaction sequence.
Sorry for long background, the question is simply;
TL;DR How does autotrophic nitrification produce N2O (and NO) during oxidation of NH4+ to NO2- to NO3-?(specifics would be appreciated).
The funeral director was asking us what we think Mum should wear in her casket.
Mum always loved to wear sarongs (fabric wraps that go around the torso and drape downward a bit like a long skirt would), so my uncle suggested that she wear a sarong in there.
The funeral director looked a bit confused, as did some of our family members, to which my uncle added:
"What's sarong with that?"
I started laughing like an idiot. He was proud of it too. The funeral director was rather shocked. We assured her, and our more proper relatives, that Mum would've absolutely loved the joke (which is very true).
His delivery was perfect. I'll never forget the risk he took. We sometimes recall the moment as a way help cushion the blows of the grieving process.
--Edit-- I appreciate the condolences. I'm doing well and the worst is behind me and my family. But thanks :)
--Edit-- Massive thanks for all the awards and kind words. And the puns! Love 'em.
Because 10+10 is twenty and 11+11 is twenty too..
Edit: thank you for awards, I have never gotten one before. I apologize that this is a repost, I did see it on TikTok and thought that it was cute and wanted to share. In the future I will check the sub for similar content before I post anything.
I would have a daughter
Hey Everyone,
I graduated from Georgia Tech and am doing my PhD at FSU - specializing in machine learning for control systems. I live and breath aquariums - both freshwater and saltwater. My latest creation is a concept for a smart water change system. This is unique in that it creates "clean tap water" from within your tanks itself. It aims to emulate what a water treatment facility does and leverages some intelligent software to treat your water. Please check out my landing page and let me know your feedback in the feedback section at the end of the page. This thing currently works well in a lab setting with turbo snails and extremely high nutrient levels - but of course it means nothing if it doesn't help those I am building it for. Please help me (and my team) build a device that solves a real problem!
I am happy to answer any question - technical or not - and want to hear all your suggestions. I would love to build prototypes for anyone that is willing to let me collect data from the devices I give them for no cost. Thank you in advance for any help you may be able to provide.
Link to my landing page (no gimmics, no click-bait) : https://ashwinvadivel.wixsite.com/treatmytank
I'm overhauling a project I've been working half-arsed on for a long time, and I want to make it alien. I'm considering ammonia-based respiration (nitrification) in a reasonably ammonia-rich atmosphere. I know little about biochemistry though. I'm quite confused and perhaps I'm horribly oversimplifying everything. Prepare for a barrage of questions (sorry).
I'm pretty much basing everything on what's written here.
-
Ammonia is not very dense. Would it all just escape higher up into the atmosphere, except where dissolved in rivers, lakes and seas? Will a slightly higher gravity help at all by pulling the atmosphere in or will there just be more collected material in the atmosphere?
-
I'm looking at using SH2 (hydrogen sulphide) as a reducing agent. Therefore, there should be sulphur ions produced assuming the hydrogen is taken by the oxygen. I'm assuming this sulphur would then react with oxygen to produce SO2. This releases quite a lot of energy, reacting explosively in air, according to wikipedia. Would this still be dangerous if diluted? Could it cause harm? Is there even a way the energy release could be harnessed?
-
Would I be right to assume the reaction can be reversed with some external energy input, photosynthesis style? Would the strong bonds in SO2 pose an issue here? Would photosynthesis reverse both steps in one go?
-
Strangely, ammonia is an inhibitor of nitrification, apparently, as is nitric acid which may be produced. Would this affect the viability of its widespread use? The world I'm 'building' is a little warmer than Earth by 30^o C or so, which means metabolisms will be a bit higher. Will this help to much of an extent?
-
What happens to the nitrate and hydrogen ion produced? Is the hydrogen 'used up' in ATP production (or equivalent - I'll cross that bridge when I get to it some other time)? Or is nitric acid formed? Would it remain dissolved until excreted/removed without causing problems or would there be acidity-based repercussions?
-
If I have all of this wrong, what would be a suitable electron donor?
