It is believed dead zones are expanding from 45 to over 700 and include what is termed dark carbon from bacteria living and dying at depth that sequester carbon and co2 absorption in water in these zones is increasing greater than scientists thought "Brewer and Peltzer's calculations suggest that the partial pressure of carbon dioxide will increase even faster in the deep oxygen minimum zones, with pCO2 increasing by 2.5 times, from 1,000 to about 2,500 micro-atmospheres over the next 100 years".. As stated before the use of man made fertilizer is thought to be behind this rapid expansion.
The work of Brewer and Peltzer 2009 https://doi.org/10.1126/science.1170756 discusses the increase of inorganic carbon in the ocean. This oceanic sink is already accounted for in the global carbon budget. In the figure from Friedlingstein et al. 2019 in the post9, it is 2.5 GtC/year. This sink, too, has its uncertainties, of course. But we are discussing a sink of organic carbon.
I am confused as dead zoned are made from the oversupply of organic carbon creating an area of low oxygen where the carbon recycling is vastly decreased hence the sequestration over longer time frames of this dead organic carbon?
Thank you for raising these interesting questions. Dead zones as discussed by Brewer and Peltzer are quantified using the so-called Respiration Index, which is the logarithm of the ratio of O2 and CO2 concentrations. The smaller the index, the more problematic it is to breathe and get energy from organic matter.
Therefore, when CO2 concentration grows, the dead zone expands. The dead zone also expands when O2 concentration declines, which has to do with the rising temperature of the ocean as O2 solubility depends on temperature. Finally, as you mention, O2 declines because of too much organic carbon (eutrophication) which is decomposed and thus spends extra O2.
Now, what you are suggesting, if I get you right, is that due to less respiration more organic carbon can be accumulating in the ocean.
I would need to think further on this. One thing is that depleted oxygen can be the result of increased oxygen consumption and hence higher (rather than lower) rates of decomposition of organic carbon. So, for example, in the paper "Decline in global oceanic oxygen content during the past five decades" https://www.nature.com/articles/nature21399 the authors discuss that a possible cause of lowered oxygen concentration at oceanic depth is "the oxygen loss in the deep oceans can have four origins. ... (c) An increase in biological activity in the upper ocean, with increased remineralization and thus oxygen consumption at depth."
Either way the sign that the dead zones are expanding I would have thought was an indicator of vastly increased carbon accumulation either mineralized in the water or not. It would then be a process of recirculation as to an indicator of permeance. The whole notion of the thermocline I find fascinating especially in regards to ocean circulation. Thanks for your insight.
Thank you for a very interesting article. Yes, we globally must save what we can of our precious forests. Global temperatures rising at an accelerating rate logically will bring more extreme temperatures days where local temperatures are above 45 degrees C when the enzymes involved in photosynthesis begin to break down. Are the frequency of such days being tracked in the studies with which you are involved?
Thank you for your comment. On land, local temperatures are greatly influenced by the presence or absence of evaporation and transpiration. When forests are logged and transpiration is reduced, most solar energy is converted into sensible heat, causing surface temperatures to rise significantly. On a dry plot, temperatures can reach 70°C or more, greatly affecting neighboring trees.
In my view, emphasizing the potential for global warming to destroy forests (which, according to recent research, is unlikely to occur before the planet warms by about 4°C) risks diverting attention from more immediate and direct threats to these ecosystems. Discussions on global warming often shift focus away from local deforestation, allowing those responsible for forest destruction to evade accountability.
We need to start by condemning the existing infrastructure in both Canada and Russia that is bending Natures will. Rivers that have run 24/7 for thousands of years should not sit still impounded into reservoirs for months at a time , than forced to flow ONLY throughout the entire winter precisely at the opposite time, normally these rivers are frozen all winter, Total containment occurs all summer, WITH 10-20 times normal volume flows all winter. We cannot let the Northern Hemispheres greatest amount of fresh water sit stagnant all summers,
This is what is going on with most of the largest fresh water rivers of this Hemisphere and particularly the now former rivers in the subarctic that are now and have been for many years, converted to stagnant pools, dammed by mega dams, waters sit all summer reservoired.
There are many in Siberia, with their warmed winter waters now preventing Arctic Sea Ice from reforming during winters and many in Northeastern Quebec that spew huge amounts of water vapor all winter ans the prevailing winds carry this water vapor to southern Greenland making it wetter and warmer
This is quite the Gordian knot of complexity, facts and suppositions. Many ecology textbooks state that soil gains energy from decomposing detritus, including plant fibers and animal parts—growth balanced by decomposition results in homeostasis. We were told soils took thousands of years to build become fertile. Plants have more agency than we give them credit. To obtain the necessary nutrients from decomposition, the bacteria and archaea that fix nitrogen and prepare minerals require plant energy. These obligate bacteria and fungi are species-specific and are contained in plant seeds. Whenever a plant photosynthesizes, about two-thirds of the carbohydrates go to building plant fibers, and one-third is pushed out as root exudate to feed soil microbes. The ratio of biomass to exudate is fixed. Step on grass or browse it, and it stimulates growth to repair; the amount of exudate increases. Grasses can build an inch of soil in a year. The sticky carbohydrates hold mineral grains so far apart that four inches of soil can hold seven inches of rainwater.
Plant fibers are very tough. Grazing animals walk on their toenails to begin the process of breaking fiber. Animals, including springtails, cut plant fibers smaller. Worms pass the mash into gizzards for grinding and then on to a chamber of bacteria that make it more useable by plants. Complex organic molecules, such as cellulose, lignin, and proteins, are broken down. The soil is then ready to undergo a series of chemical reactions to form humus. Humus, the black gold of soil, aggregating and holding together, is very stable and can retain carbon for thousands of years, facilitating long-term carbon sequestration. This process of accumulating carbon results in the world’s soil containing approximately 2,800 billion tons of carbon, while biomass contains only 564 billion tons. Perhaps there is more carbon in the ground, deeper soils, than we know.
Rob, I agree about the knot of complexity. Some of the most productive ecosystems on the Earth, the Amazon rainforest, has almost no soil in comparison to some non-forest ecosystems. On the other hand, in grasslands plant fibers are very tough because they are dry. In forests, there is no need for animals to walk on trees for the trees to decompose. This is easily done by microorganisms provided there is enough water.
I would say we still don't know much. I agree with your point in another note, "Who are we to decide the ecosystem ranking?"
However, the ecosystems themselves can decide. If a grassland spontaneously develops into a forest, that could mean that the grassland is an early successional stage developing after a disturbance.
Could it be the the depth of soils (the carbon storage) is a function of the ecosystem's needs for building soil water storage capacity for tough times? In your examples, the Amazon doesn't (or didn't) have a need for water storage due to the volume of annual rainfall. The prairies build the deep soils for long droughty periods and so on. I know it's more complicated than this but to Rob's point, this is part of plant agency - adapting for water scarcity by storing water in the ground or in the atmosphere or both.
"Could it be the the depth of soils (the carbon storage) is a function of the ecosystem's needs for building soil water storage capacity for tough times?"
Thank you for this very insightful comment. Why some ecosystems accumulate so much carbon in soil and others don't is a question that has kept me curious for a long time.
However, trees in the Amazon do have access to moisture in the absence of rain, some of them reach with their roots to deep underground layers, and generally, during the drier season, the Amazon is greening even more than during the wet season (contrary to other ecosystems).
Nevertheless, this does not exclude a possibility that carbon-rich soil is a means for say steppe-like ecosystems to enhance the storage of water.
Also, boreal forests have a significantly higher soil carbon content than the Amazon, maybe this could be related to the necessity to store meltwater efficiently after winte. Much food for thought.
Anastassia - I tried to respond to one your notes on this, but I'm not sure if it was actually published on line. If this is a duplication I apologize, but I wanted to make sure I had responded. I have been studying ecohydrology for a couple years now as an un-paid, very part-time pursuit. So I have not been able to go as deep as I want. But if any of this helps in your work, great. Here are a few references about this topic:
I agree that there is not a straightforward correlation between precip and rooting zone storage/depth; nothing is that simple. But I do firmly believe plants build out their bodies and their immediate environment to manage climate variability, and in particular water availability. I also believe that these strategies are all consistent with your biotic pump concept. In fact, they are integral to the concept.
Scott, Thank you for the citations. Unfortunately our agency is no less than plants. Air saturated with moisture from off water blows over our urban structures, heat islands on the shore, and expands as it warms. This enables it to carry more moisture which is drawn from the land further drying it and adding more moisture heat energy to the atmosphere. This is worst than a drought because it is a permanent feature. The solution is to cool the urban hardscape with more vegetation and soil, if only rooftop gardens.
Yes, if there was less carbohydrate decomposition beneath boreal forests than in the Amazon there would be more carbon stored. Nature is deliciously complex while we grope for simple explanations.
Regarding the soil question: It's worth remembering that our analyses of soil carbon rarely go beyond 3 meters and often stick to the top 1 meter. Meanwhile, tropical soil profiles may stretch 6-9 meters or more (~18 to 28 feet) below the surface. At least in Puerto Rico's experimental stations, they remain nutrient rich at depth. So my bet is on deep soil storage and also sediment removal and storage in the deep sea during high-intensity events such as hurricanes and big floods.
Also, many tropical ecologists (including Ariel E. Lugo) could readily pinpoint the "missing sink" of yesteryear in tropical forests. And Yude Pan and her colleagues published a Nature paper in 2024 using in-situ measurements to account for the "missing carbon" of today.
Thanks for the citation. Its easy to underestimate carbon in soil and temperate grasslands because people tend only to notice what they bump into. With biomass holding 564 billion tons carbon and soil holding 2800 billion tons, best to go for two for one special. Soil holds water and needs moisture to live. Time for the Earth Rehydration Revolution to pick up where the Industrial Revolution left off. More water in the ground, less stormwater, and less heat-bearing water in the atmosphere.
The imperative is to understand the true time associated with evolution and come to the understanding that this is in conflict with our economic system, In all context we are out of time and therefore should not associate the time value of money with evolutionary time, once we free ourselves of this we will be able to create the money as a separate ledger for the ecological necessities and fully employ the huge underutilized resource of human capital in many parts of the world for this essential endeavor. Nature is not our slave and gives us trillions of dollars of benefits every year, Governments need a separate ledger to account for this so we can print this money to look after it
If I understand you correctly, I hear that the signal of higher atmospheric CO2 concentration drives nature to store more carbon, regulating a very stable temperature regime. This also creates a highly non-linear system.
The nature question that emerges to me: are there tipping points? What does the geological records teach us? And what happened before that tipping Point was hit?
Thank you. Yes, a prime example of the 'biotic pump' and the repercussions of its failure is seen in the film Aluna with the the Kogi Indians pointing out that the destruction of a mangrove swamp on the coast caused the rain to stop falling on their mountain inland. The so called 'scientists' they had on the film treated the Kogi as ignorant, saying water cannot flow up hill... https://www.alunathemovie.com/ However the Kogi amply demonstrate they have a knowledge and wisdom that we cannot explain.
This clash of 'cultures' actually highlights something much more severe for us - the emerging realisation that the rationalist/reductionist/materialist paradigm does not work in the Real World! We are at another Copernican/Ptolomaic boundary, this time relating to our place in the universe (?!) and what we 'orbit' around as a species...
I so appreciate that you share this info and write so clearly.
Helping to restore #smallwatercycles ##waterstories 💯 💧 💚 🤝
It is believed dead zones are expanding from 45 to over 700 and include what is termed dark carbon from bacteria living and dying at depth that sequester carbon and co2 absorption in water in these zones is increasing greater than scientists thought "Brewer and Peltzer's calculations suggest that the partial pressure of carbon dioxide will increase even faster in the deep oxygen minimum zones, with pCO2 increasing by 2.5 times, from 1,000 to about 2,500 micro-atmospheres over the next 100 years".. As stated before the use of man made fertilizer is thought to be behind this rapid expansion.
The work of Brewer and Peltzer 2009 https://doi.org/10.1126/science.1170756 discusses the increase of inorganic carbon in the ocean. This oceanic sink is already accounted for in the global carbon budget. In the figure from Friedlingstein et al. 2019 in the post9, it is 2.5 GtC/year. This sink, too, has its uncertainties, of course. But we are discussing a sink of organic carbon.
I am confused as dead zoned are made from the oversupply of organic carbon creating an area of low oxygen where the carbon recycling is vastly decreased hence the sequestration over longer time frames of this dead organic carbon?
Thank you for raising these interesting questions. Dead zones as discussed by Brewer and Peltzer are quantified using the so-called Respiration Index, which is the logarithm of the ratio of O2 and CO2 concentrations. The smaller the index, the more problematic it is to breathe and get energy from organic matter.
Therefore, when CO2 concentration grows, the dead zone expands. The dead zone also expands when O2 concentration declines, which has to do with the rising temperature of the ocean as O2 solubility depends on temperature. Finally, as you mention, O2 declines because of too much organic carbon (eutrophication) which is decomposed and thus spends extra O2.
Now, what you are suggesting, if I get you right, is that due to less respiration more organic carbon can be accumulating in the ocean.
I would need to think further on this. One thing is that depleted oxygen can be the result of increased oxygen consumption and hence higher (rather than lower) rates of decomposition of organic carbon. So, for example, in the paper "Decline in global oceanic oxygen content during the past five decades" https://www.nature.com/articles/nature21399 the authors discuss that a possible cause of lowered oxygen concentration at oceanic depth is "the oxygen loss in the deep oceans can have four origins. ... (c) An increase in biological activity in the upper ocean, with increased remineralization and thus oxygen consumption at depth."
Either way the sign that the dead zones are expanding I would have thought was an indicator of vastly increased carbon accumulation either mineralized in the water or not. It would then be a process of recirculation as to an indicator of permeance. The whole notion of the thermocline I find fascinating especially in regards to ocean circulation. Thanks for your insight.
Thank you for a very interesting article. Yes, we globally must save what we can of our precious forests. Global temperatures rising at an accelerating rate logically will bring more extreme temperatures days where local temperatures are above 45 degrees C when the enzymes involved in photosynthesis begin to break down. Are the frequency of such days being tracked in the studies with which you are involved?
Thank you for your comment. On land, local temperatures are greatly influenced by the presence or absence of evaporation and transpiration. When forests are logged and transpiration is reduced, most solar energy is converted into sensible heat, causing surface temperatures to rise significantly. On a dry plot, temperatures can reach 70°C or more, greatly affecting neighboring trees.
In my view, emphasizing the potential for global warming to destroy forests (which, according to recent research, is unlikely to occur before the planet warms by about 4°C) risks diverting attention from more immediate and direct threats to these ecosystems. Discussions on global warming often shift focus away from local deforestation, allowing those responsible for forest destruction to evade accountability.
We need to start by condemning the existing infrastructure in both Canada and Russia that is bending Natures will. Rivers that have run 24/7 for thousands of years should not sit still impounded into reservoirs for months at a time , than forced to flow ONLY throughout the entire winter precisely at the opposite time, normally these rivers are frozen all winter, Total containment occurs all summer, WITH 10-20 times normal volume flows all winter. We cannot let the Northern Hemispheres greatest amount of fresh water sit stagnant all summers,
This is what is going on with most of the largest fresh water rivers of this Hemisphere and particularly the now former rivers in the subarctic that are now and have been for many years, converted to stagnant pools, dammed by mega dams, waters sit all summer reservoired.
There are many in Siberia, with their warmed winter waters now preventing Arctic Sea Ice from reforming during winters and many in Northeastern Quebec that spew huge amounts of water vapor all winter ans the prevailing winds carry this water vapor to southern Greenland making it wetter and warmer
From my perspective, the largest damage from dams in Siberia is that the water reservoirs that are built destroy a lot of natural forest.
This is quite the Gordian knot of complexity, facts and suppositions. Many ecology textbooks state that soil gains energy from decomposing detritus, including plant fibers and animal parts—growth balanced by decomposition results in homeostasis. We were told soils took thousands of years to build become fertile. Plants have more agency than we give them credit. To obtain the necessary nutrients from decomposition, the bacteria and archaea that fix nitrogen and prepare minerals require plant energy. These obligate bacteria and fungi are species-specific and are contained in plant seeds. Whenever a plant photosynthesizes, about two-thirds of the carbohydrates go to building plant fibers, and one-third is pushed out as root exudate to feed soil microbes. The ratio of biomass to exudate is fixed. Step on grass or browse it, and it stimulates growth to repair; the amount of exudate increases. Grasses can build an inch of soil in a year. The sticky carbohydrates hold mineral grains so far apart that four inches of soil can hold seven inches of rainwater.
Plant fibers are very tough. Grazing animals walk on their toenails to begin the process of breaking fiber. Animals, including springtails, cut plant fibers smaller. Worms pass the mash into gizzards for grinding and then on to a chamber of bacteria that make it more useable by plants. Complex organic molecules, such as cellulose, lignin, and proteins, are broken down. The soil is then ready to undergo a series of chemical reactions to form humus. Humus, the black gold of soil, aggregating and holding together, is very stable and can retain carbon for thousands of years, facilitating long-term carbon sequestration. This process of accumulating carbon results in the world’s soil containing approximately 2,800 billion tons of carbon, while biomass contains only 564 billion tons. Perhaps there is more carbon in the ground, deeper soils, than we know.
Rob, I agree about the knot of complexity. Some of the most productive ecosystems on the Earth, the Amazon rainforest, has almost no soil in comparison to some non-forest ecosystems. On the other hand, in grasslands plant fibers are very tough because they are dry. In forests, there is no need for animals to walk on trees for the trees to decompose. This is easily done by microorganisms provided there is enough water.
I would say we still don't know much. I agree with your point in another note, "Who are we to decide the ecosystem ranking?"
However, the ecosystems themselves can decide. If a grassland spontaneously develops into a forest, that could mean that the grassland is an early successional stage developing after a disturbance.
Could it be the the depth of soils (the carbon storage) is a function of the ecosystem's needs for building soil water storage capacity for tough times? In your examples, the Amazon doesn't (or didn't) have a need for water storage due to the volume of annual rainfall. The prairies build the deep soils for long droughty periods and so on. I know it's more complicated than this but to Rob's point, this is part of plant agency - adapting for water scarcity by storing water in the ground or in the atmosphere or both.
"Could it be the the depth of soils (the carbon storage) is a function of the ecosystem's needs for building soil water storage capacity for tough times?"
Thank you for this very insightful comment. Why some ecosystems accumulate so much carbon in soil and others don't is a question that has kept me curious for a long time.
However, trees in the Amazon do have access to moisture in the absence of rain, some of them reach with their roots to deep underground layers, and generally, during the drier season, the Amazon is greening even more than during the wet season (contrary to other ecosystems).
Nevertheless, this does not exclude a possibility that carbon-rich soil is a means for say steppe-like ecosystems to enhance the storage of water.
Also, boreal forests have a significantly higher soil carbon content than the Amazon, maybe this could be related to the necessity to store meltwater efficiently after winte. Much food for thought.
Anastassia - I tried to respond to one your notes on this, but I'm not sure if it was actually published on line. If this is a duplication I apologize, but I wanted to make sure I had responded. I have been studying ecohydrology for a couple years now as an un-paid, very part-time pursuit. So I have not been able to go as deep as I want. But if any of this helps in your work, great. Here are a few references about this topic:
1. Plants as sensors: vegetation response to rainfall predicts root-zone water storage capacity in Mediterranean-type climates https://research.fs.usda.gov/treesearch/61515
2. Influence of soil and climate on root zone storage capacity https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/2015WR018115
3. Climate controls how ecosystems size the root zone storage capacity at catchment scale https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/2014GL061668
I agree that there is not a straightforward correlation between precip and rooting zone storage/depth; nothing is that simple. But I do firmly believe plants build out their bodies and their immediate environment to manage climate variability, and in particular water availability. I also believe that these strategies are all consistent with your biotic pump concept. In fact, they are integral to the concept.
Scott, Thank you for the citations. Unfortunately our agency is no less than plants. Air saturated with moisture from off water blows over our urban structures, heat islands on the shore, and expands as it warms. This enables it to carry more moisture which is drawn from the land further drying it and adding more moisture heat energy to the atmosphere. This is worst than a drought because it is a permanent feature. The solution is to cool the urban hardscape with more vegetation and soil, if only rooftop gardens.
Yes, if there was less carbohydrate decomposition beneath boreal forests than in the Amazon there would be more carbon stored. Nature is deliciously complex while we grope for simple explanations.
Regarding the soil question: It's worth remembering that our analyses of soil carbon rarely go beyond 3 meters and often stick to the top 1 meter. Meanwhile, tropical soil profiles may stretch 6-9 meters or more (~18 to 28 feet) below the surface. At least in Puerto Rico's experimental stations, they remain nutrient rich at depth. So my bet is on deep soil storage and also sediment removal and storage in the deep sea during high-intensity events such as hurricanes and big floods.
Also, many tropical ecologists (including Ariel E. Lugo) could readily pinpoint the "missing sink" of yesteryear in tropical forests. And Yude Pan and her colleagues published a Nature paper in 2024 using in-situ measurements to account for the "missing carbon" of today.
https://www.nature.com/articles/s41586-024-07602-x
Melanie
Thanks for the citation. Its easy to underestimate carbon in soil and temperate grasslands because people tend only to notice what they bump into. With biomass holding 564 billion tons carbon and soil holding 2800 billion tons, best to go for two for one special. Soil holds water and needs moisture to live. Time for the Earth Rehydration Revolution to pick up where the Industrial Revolution left off. More water in the ground, less stormwater, and less heat-bearing water in the atmosphere.
I have used this to wrap-up today's blog post https://drjohnsblog.substack.com/p/tariffs-bitcoin-standard-and-resource
Thank you, John, always appreciated!
The imperative is to understand the true time associated with evolution and come to the understanding that this is in conflict with our economic system, In all context we are out of time and therefore should not associate the time value of money with evolutionary time, once we free ourselves of this we will be able to create the money as a separate ledger for the ecological necessities and fully employ the huge underutilized resource of human capital in many parts of the world for this essential endeavor. Nature is not our slave and gives us trillions of dollars of benefits every year, Governments need a separate ledger to account for this so we can print this money to look after it
While we still have time
Very cool analysis!
If I understand you correctly, I hear that the signal of higher atmospheric CO2 concentration drives nature to store more carbon, regulating a very stable temperature regime. This also creates a highly non-linear system.
The nature question that emerges to me: are there tipping points? What does the geological records teach us? And what happened before that tipping Point was hit?
Some insights from geological records are discussed in "Natural Ecosystems and Climate Stabilization", https://bioticregulation.substack.com/p/natural-ecosystems-and-climate-stabilization , see the figure from Arnscheidt and Rothman 2022, but otherwise it is a huge topic.
Thank you. Yes, a prime example of the 'biotic pump' and the repercussions of its failure is seen in the film Aluna with the the Kogi Indians pointing out that the destruction of a mangrove swamp on the coast caused the rain to stop falling on their mountain inland. The so called 'scientists' they had on the film treated the Kogi as ignorant, saying water cannot flow up hill... https://www.alunathemovie.com/ However the Kogi amply demonstrate they have a knowledge and wisdom that we cannot explain.
This clash of 'cultures' actually highlights something much more severe for us - the emerging realisation that the rationalist/reductionist/materialist paradigm does not work in the Real World! We are at another Copernican/Ptolomaic boundary, this time relating to our place in the universe (?!) and what we 'orbit' around as a species...
Thank you for very interesting links.