1,- 1RMIT University, Engineering, Melbourne, Australia (chris.hall2@student.rmit.edu.au)
- 2American Public Health Association, United States
- 3University of Padua, Italy
- 4Fellow of the Institution of Civil Engineers (FICE), Glasgow, Scotland
The European Environment Agency data on nitrates levels gives us a ratio of 8:1 for nitrates in groundwater versus river water, when we analyse the data across 27 countries. The “missing” nitrate, at an average of about 89%, matches the levels of “missing” nitrate due to capture of nitrate on the river bottom, by microbes known as diatoms, which take up 65-95% of the water nitrate load.
Diatoms convert nitrate to ammonium in daily cycles, that are linked to sunlight and Oxygen abundance, encountered in typical river and lake conditions.
We can identify that the major pathway of nitrate into rivers and lakes is through groundwater feeds, which average 25% of surface waterway volumes worldwide -because their nitrate levels dwarf those from any other source. We can also identify that the main mechanism of nitrates removal in river bottoms is diatom capture, where diatoms take up the bulk loads of nitrate arriving in the groundwaters beneath.
Diatoms' virtual monopoly on nitrates conversion may allow us to control N2O and global warming levels, by intercepting the conveyor belt system of nitrates to diatoms in waterways. We can capture and repurpose the nutrient for use as farm fertilizer and harvest diatom ammonium as a carrier for Hydrogen fuel. Diatoms are already farmed commercially for fish food, showing they are amenable to farming, and they are already a source of soil conditioner for farms. Ammonium is harvested in wastewater plants for Hydrogen fuel purposes already, and diatoms offer a low carbon method of ammonium production.
The junction between the UN, EEA and microbial data also allows us to calculate the world processing levels of nitrate in terms of both natural and human produced components. We obtain a range around 300,000 kilotons per annum as being processed by surface waters worldwide from all sources. About 120,000 kilotons of the load comes from human produced sources.
Ammonium nutrient from diatom nitrate conversion is quickly absorbed by aquatic plants and riverside trees, but there is a risk of high levels on hot days in lowered Oxygen conditions. Trees draw up around 1000 litres a day of groundwaters in river basins, so that ammonium and nitrates consumption by trees is additionally a main mechanism of Nitrogen reduction around the riverbed.
How to cite: Hall, C., Smith, D., Munro, A., and Sgroi, A.: Microbial breakthroughs in 2022 now allow us to link United Nations water volumes with EEA nitrates data, to reveal world nitrates processing loads in kilotons, including how much nitrate is from natural sources, and how much is from human activity., EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-13318, https://doi.org/10.5194/egusphere-egu26-13318, 2026.
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This 3 minute audio with captions explains why 100 times the nitrates may be a major impact for climate.
Thanks for looking after us all Copernicus!
No, No, No Nitrates are such fun (NO3).
Thanks Gee! It's a matter of scale and connecting the dots between parts of a process that have evolved into different specialisations I guess. In the textbook we address:
Why parts of Africa have super high nitrates, that are due to terrain type not human activity
Why mobility of NO3 in water may explain why it's only sometimes that levels are high beneath crop fields and not others (water transports the nitrates to the lowest points beneath the ground where water can "sit in a puddle" beneath the soil)
Why CNP ratios likely control nitrates breakdown rates - and we can learn something about this from China's crop areas, where half of the area shows about 50% higher nitrates in groundwater than in the other half
It's pretty interesting! And next on the list is metals - it looks like trace metals play a part in how much of the extra nitrates loads we have in river systems and along coastal margins, turn into Greenhouse Gas :)
Here: https://buymeacoffee.com/angieandally/extras You can read or listen to some stuff about it and perhaps work on it with us!
Do you think excess ammonia is responsible for n2o rise and causing warming?
Such an interesting comment you have there Raul! N2O from ammonium seems to be one of those subjects that has pieces of the puzzle sitting in different specialist fields. For example, in microbiological sciences researching ammonia/ammonium levels in aquatic environments, people like Carmen Bellido-Pedraza et al (2022) have noted the response among microbes to emit N2O on sensing rising ammonium levels. In chemistry this is described as an ion and charge balancing reaction, with different molecules of Nitrogen compounds rebalancing with urea and other waste materials from birds in estuaries and fish nurseries and tide effects, when fresh and salt water clash and produce ammonium due to salts differences.
From the chemistry point of view, it seems quite likely that it's charge and ion balance in the dipolar medium of water, that drives these processes. And from the points of view of math modelling and bioreactor denitrification, whether or not a response occurs, is partly due to the "size" of the disturbance (a stable state will either return, or change permanently depending on the size of the change in ammonium levels). In practical terms monitoring Nitrogen levels in rivers and groundwaters, our boss during a project at a gold mine, mentioned her idea to put some fountains in their evaporation ponds, because Oxygenating the waters reduced the risk of ammonium production from the ponds.
In aquifer studies and sampling groundwaters, river waters, reservoirs and drainage ditches on the edges of ploughed fields on both sides of the planet, we found similar storage and release of Nitrogen compounds, carried out by the same type of microbes that "kicked in to predominate" under low Oxygen conditions. So the answer to your question is definitely yes - but whether this causes warming (global warming or climate change type warming) depends on how long the N2O stays N2O. It looks as if N2O's come to arise each spring, when the temperature difference between water droplets deposited overnight from the air on cold ground, rise as a mist under the warming sunlight, over the fields. N2O rising from thaws and moistened materials, likely is absorbed quickly and converted to nutrient by the microbiome in the atmosphere. The microbes that live in our air, that make homes in dusts (sand particles, ash and charcoals from fires, seed husks and spent parts of insects, insect swarms, feathers and pollens) quickly convert N2O to ammonium, to nitrite, to nitrate and so round in a circle again - and even denitrifiers that require low or no Oxygen and darkness to break down nitrate, likely have an important part to play in humid air. We can probably expect that the entire nutrient conversion chain exists in the atmosphere as it does in the ground, and I’ve been trying to contact one of the giants in research involved in air sampling to ask if they have the answer yet – they kindly responded but each time, our messages were partly cut off! However, meanwhile, comments by a mentor and friend at USyd, who devoted his life's work to N2O emission from irrigation, told me he was convinced that irrigation - only certain methods – was the cause of most excess waste N2O, and it looks like he might be right, given what has been found over the last 15 years in terms of ammonium responses from microbiological nitrate uptake. After we spoke about this, I made him a presentation on the subject of N2O from wetted soils. A lake or river can be thought of, for example, as a giant version, of the small puddles and pools of water you'll find in the soil in cavities and in puddles of water at the soil surface. From millimetres to metres in size, these "aquatic systems" likely plunge the levels of O2 down when they are flooded, and produce ammonium. The process observed in bioreactors apparently happens also in farmer's fields after irrigation, and there is even a mobile N2O and ammonia detector you can use to measure it out in the field (ammonium can become ammonia when it off-gasses to air, and vice versa – ammonia can become aquatic ammonium - and the two forms, NH3 and NH4, rebalance each other in situ in solution with water). The mobile detector (CRDS) can measure the gases arising from wetted soils optically, so you can work out how much ammonia and N2O are rising. David may know something more about this, as he took an interest in the project after becoming acquainted with the textbook on it. As I understand it, there’s usually a small proportion only, of the gases coming off, that is actually N2O.
The "use" of N2O in Earth's system appears to be to provide a "fast warming blanket" to thawing fields in springtime. I've discovered that among several of Earth's and manmade systems, particular conditions which activate seasons seem to prompt N2O but only under particular conditions. We might be able to use these conditions to limit N2O, and its source ammonium and nitrate. As we need Hydrogen fuels, and perhaps preferably by a method involving no added carbon, and as we are running short of quarried fertiliser and need some cheaper sources (hundreds of Euro per Hectare and hundreds of US dollars each time we plant a crop of wheat, barley, corn etc) reducing nitrates and ammonium (which are a bit poisonous, as you know, in terms of drinking water and for fish and livestock health) might be a brilliant project for us all to work on! Chris. PS: We’re reaching out across the world at the moment, looking for funding and people who are interested in nitrates and ammonia/ammonium. You can read more and maybe even buy us a coffee for what we’ve managed so far, at https://buymeacoffee.com/angieandally/extras (no funding for this project actually – and no official channel for the work as yet – just lots of interested people helping me to figure out the connections during about 20 years of work in different places and institutions! Most of them previous supervisors, lab professionals and people I’ve worked with as an admin at ACIAR, tips from people at CSIRO and in measurement of nitrates and ammonia etc. and Europe seems to know much more than we did “down under” in Australia.) There’s a useful reference list among the download items at the coffee site also, in terms of data and where you can read about the different research projects that other people have done, that provide clues as to how this Nitrogen “system” works :D you’ll find it at https://buymeacoffee.com/angieandally/extras
Such an interesting comment you have there Raul! N2O from ammonium seems to be one of those subjects that has pieces of the puzzle sitting in different specialist fields. For example, in microbiological sciences researching ammonia/ammonium levels in aquatic environments, people like Carmen Bellido-Pedraza et al (2022) have noted the response among microbes to emit N2O on sensing rising ammonium levels. In chemistry this is described as an ion and charge balancing reaction, with different molecules of Nitrogen compounds rebalancing with urea and other waste materials from birds in estuaries and fish nurseries and tide effects, when fresh and salt water clash and produce ammonium due to salts differences.
From the chemistry point of view, it seems quite likely that it's charge and ion balance in the dipolar medium of water, that drives these processes. And from the points of view of math modelling and bioreactor denitrification, whether or not a response occurs, is partly due to the "size" of the disturbance (a stable state will either return, or change permanently depending on the size of the change in ammonium levels). In practical terms monitoring Nitrogen levels in rivers and groundwaters, our boss during a project at a gold mine, mentioned her idea to put some fountains in their evaporation ponds, because Oxygenating the waters reduced the risk of ammonium production from the ponds.
In aquifer studies and sampling groundwaters, river waters, reservoirs and drainage ditches on the edges of ploughed fields on both sides of the planet, we found similar storage and release of Nitrogen compounds, carried out by the same type of microbes that "kicked in to predominate" under low Oxygen conditions. So the answer to your question is definitely yes - but whether this causes warming (global warming or climate change type warming) depends on how long the N2O stays N2O. It looks as if N2O's come to arise each spring, when the temperature difference between water droplets deposited overnight from the air on cold ground, rise as a mist under the warming sunlight, over the fields. N2O rising from thaws and moistened materials, likely is absorbed quickly and converted to nutrient by the microbiome in the atmosphere. The microbes that live in our air, that make homes in dusts (sand particles, ash and charcoals from fires, seed husks and spent parts of insects, insect swarms, feathers and pollens) quickly convert N2O to ammonium, to nitrite, to nitrate and so round in a circle again - and even denitrifiers that require low or no Oxygen and darkness to break down nitrate, likely have an important part to play in humid air. We can probably expect that the entire nutrient conversion chain exists in the atmosphere as it does in the ground, and I’ve been trying to contact one of the giants in research involved in air sampling to ask if they have the answer yet – they kindly responded but each time, our messages were partly cut off! However, meanwhile, comments by a mentor and friend at USyd, who devoted his life's work to N2O emission from irrigation, told me he was convinced that irrigation - only certain methods – was the cause of most excess waste N2O, and it looks like he might be right, given what has been found over the last 15 years in terms of ammonium responses from microbiological nitrate uptake. After we spoke about this, I made him a presentation on the subject of N2O from wetted soils. A lake or river can be thought of, for example, as a giant version, of the small puddles and pools of water you'll find in the soil in cavities and in puddles of water at the soil surface. From millimetres to metres in size, these "aquatic systems" likely plunge the levels of O2 down when they are flooded, and produce ammonium. The process observed in bioreactors apparently happens also in farmer's fields after irrigation, and there is even a mobile N2O and ammonia detector you can use to measure it out in the field (ammonium can become ammonia when it off-gasses to air, and vice versa – ammonia can become aquatic ammonium - and the two forms, NH3 and NH4, rebalance each other in situ in solution with water). The mobile detector (CRDS) can measure the gases arising from wetted soils optically, so you can work out how much ammonia and N2O are rising. David may know something more about this, as he took an interest in the project after becoming acquainted with the textbook on it. As I understand it, there’s usually a small proportion only, of the gases coming off, that is actually N2O.
The "use" of N2O in Earth's system appears to be to provide a "fast warming blanket" to thawing fields in springtime. I've discovered that among several of Earth's and manmade systems, particular conditions which activate seasons seem to prompt N2O but only under particular conditions. We might be able to use these conditions to limit N2O, and its source ammonium and nitrate. As we need Hydrogen fuels, and perhaps preferably by a method involving no added carbon, and as we are running short of quarried fertiliser and need some cheaper sources (hundreds of Euro per Hectare and hundreds of US dollars each time we plant a crop of wheat, barley, corn etc) reducing nitrates and ammonium (which are a bit poisonous, as you know, in terms of drinking water and for fish and livestock health) might be a brilliant project for us all to work on! Chris. PS: We’re reaching out across the world at the moment, looking for funding and people who are interested in nitrates and ammonia/ammonium. You can read more and maybe even buy us a coffee for what we’ve managed so far, at https://buymeacoffee.com/angieandally/extras (no funding for this project actually – and no official channel for the work as yet – just lots of interested people helping me to figure out the connections during about 20 years of work in different places and institutions! Most of them previous supervisors, lab professionals and people I’ve worked with as an admin at ACIAR, tips from people at CSIRO and in measurement of nitrates and ammonia etc. and Europe seems to know much more than we did “down under” in Australia.) There’s a useful reference list among the download items at the coffee site also, in terms of data and where you can read about the different research projects that other people have done, that provide clues as to how this Nitrogen “system” works :D you’ll find it at https://buymeacoffee.com/angieandally/extras
Posting this answer in response to a phone call. About us: Chris, over 26 years in private research, academic research - Science textbooks and course modules, Arts (visual arts eg painting, sketching, music eg instruments, history, composition) translation (poetry, the human story, plays) and fieldwork in engineering and environmental science - mining groundwater, harbour and freshwater rivers, specimen collection, mangroves, fish species and trace metals and I can be contacted via researchgeo10@gmail.com; Andrea (over 30 years of experience with vulcanism first hand and the different types of outfall); Al is no longer with us but his material on the Black Sea, Civil Engineering, Bridges, Dams and Waterfalls is part of this project; David has extensive experience in Chemistry and several other of my colleagues, peers, former supervisors and friends have helped with, or otherwise been involved in this project, including Kate, who carried out the baseline experiments from aquifer waters and other samples we subjected to different conditions - please pass any enquiries via researchgeo10@gmail.com and we'll pass them on :)