Thank you for this, Anastassia. If I understand you correctly, you are saying CO2 fertilization cannot account for the missing carbon sink because what is gained in photosynthesis is later released as part of decomposition, thus a net zero. However, in healthy systems, soil microbes are able to draw a certain percentage of that carbon into the soil for long term storage.
I suppose a similar thing happens in the ocean, in which carbon is calcified as marine shells.
Is this what Bar-on et al. mean by non-living pools, pools of inorganic carbon in soils and the ocean created by living processes?
I've noticed your observation about the scientific attitude to the carbon sink. There seems to be a desire to minimize the role of life in the system, to keep the entire matter purely physical. I don't understand this motivation, but it seems deeply ingrained. I think of Copernicus and the Church. The Church was willing to accept Copernicus' findings in a scientific sense, but not in a metaphorical sense. "Fine, the universe is not heliocentric, but it still, in our minds and cultures, will revolve around us." We seem determined to not acknowledge the metaphorical implications of biotic regulation, without which our bodies, or any other living thing for that matter, including the climate, can not function. Meanwhile, the destruction continues, which is perhaps the point.
Rob, the result of Bar-on et al. is that carbon did not accumulate in trees. Fullstop. This does mean however that it accumulated somewhere else, in soil and/or dissolved organic matter in the ocean.
CO2 fertilization, by definition, means that photosynthesis is carbon-limited and increases with increasing concentration of atmospheric carbon dioxide. This does not explain the sink, because for there to be a sink, there must be a correlated response of autotrophs and heterotrophs, with the latter refraining from consuming the extra food synthesized by plants. This reaction of heterotrophs has nothing to do with any "fertilization".
As Rob mentioned below, the missing sink could be explained by the "Liquid Carbon Pathway".
Plants exude up to 50% or more of the carbohydrates they produce through photosynthesis into the soil via their root hairs to feed bacteria and fungi.
These microbes use it as a food source and fix most of it as stable carbon molecules in the soil. In return they provide nutrients and water to the plants, otherwise unavailable. It's the rhisophagy cycle.
~50% of the CO2 plants absorb from the atmosphere is fixed in the soil through root exudates via microbes. But only if the soil ecosystem is healthy and alive with microbes and higher order soil fauna (mites, worme etc).
Dr Christine Jones, soil ecologist coined the term "Liquid Carbon Pathway"
Professor James White has some fascinating research and imagery showing bacteria interacting with plant root hairs, worth a look.
Grasses are the only plants that exude 50% of photosynthesized carbohydrates to build soils. Most plants exude about one third. This is why grasses are excellent pioneer plants preparing the soil for others. Silviopasture, grasses and trees together is the best carbon sink, better than just grass or trees.
"Grasses are the only plants that exude 50% of their photosynthesized carbohydrates to build soils. Most plants exude about one-third."
Rob, thank you for this comment.
Let's consider this statement in light of the law of matter conservation. The preindustrial atmosphere contained approximately 600 gigatons of carbon, while the rate of photosynthesis on land was around 50 gigatons of carbon per year. If plants exuded 30% of their carbohydrates to build soil—about 15 gigatons of carbon per year—and heterotrophs did not decompose this exudate but instead allowed it to accumulate, ALL atmospheric carbon would be depleted in just 40 years.
Clearly, this does not happen. CO₂ concentrations remain relatively stable over extended periods because, in a healthy ecosystem in the absence of disturbances, synthesis and decomposition are closely balanced.
Now, if we aim to understand which ecosystems can most effectively respond to carbon disturbances, we must consider the community's response as a whole. A system where plants exude 50% of their carbohydrates to the soil but are coupled with heterotrophs that rapidly decompose this input could have a smaller compensatory impact than one where plants exude less but are paired with heterotrophs that allow more of this exudate to persist in the soil.
Just one example of ecosystem complexity thinking.
Thank you, Steve. When aerobic microbes use something as a food source, they decompose organic carbon, say (CH2O)n, into CO2 and water. When you say that they fix most of it "as stable carbon molecules" in soil, this means that they do not eat them up fully, but store in an inactive organic form. It still remains a source of energy that some other microbes could use but they choose not to. As I quoted in the post, "the turnover time of organic compounds in soil is mostly determined not by their chemical composition but by functioning of the entire ecological community, plants and soil biota included", with a reference to Schmidt et al. 2011, which is in my opinion a great article titled "Persistence of soil organic matter as an ecosystem property", Nature https://doi.org/10.1038/nature10386
Hi Anastassia, thanks for the link, looks great, I'll try to get access! This is such an interesting space, so much to discover that's critical to our future.
My mind keeps going back to the grasslands / rangelands / prairies in North America, Australia particularly, and the stories of 3m deep carbon rich soils full of diversity and life. Soils which are now dead with almost no carbon or life.
And the stories of people now managing their land and animals who are starting to rebuild their soil carbon and ecosystem function. Heading towards those original deep rich fertile soils.
I can't help but think that healthy ecosystems must have a process that results in carbon building up in the soil naturally. Where more is retained in the ground than decomposed and released.
I wonder if it could be related to soil depth, and if most active microbial activity is in the top layers of soil profiles generally? As you go deeper fewer decomposing microbes eat the carbon??
Maybe arbuscular mycorrhizal fungi deposit their glomalin deeper than the majority of active decomposers. Maybe someone has done this research.
Another question is if carbon does build up in soil, how does it not just keep going as you mention above in your comment to Rob, and deplete all atmospheric carbon? Or does it keep going and globally there is balance from other processes that release carbon?? Maybe 3m deep is the limit? Who knows!!??
Hi Steve nothing lives forever and I would think as soon as an organism or plant dies the readily available nutrients would be reused carbon included. As to the depth question I would assume that the other nutrients would be the limiting factors to the build up of total biomass both above and below ground, this could be seen in areas of high nutrient vs areas of low all others being equal. NZ is a good example with a close mixture of volcanic, basalt and clay topsoil and the differing growth and soil depth found.
I wrote in response to a previous article the notion that the mining and manufacturing of fertilizer and irrigation has had an impact on the equilibrium of these static cycles and show through graph interpretation the result temperature regulation by feeding the biotic system. In my mind the movement of the main components of organic growth through waste, surface runoff, groundwater and the air, both fire and natural recycling of this would change the static dynamics of every impacted system ( I would assume most of the planet). It is right to concentrate on the ocean as the missing sink as this is where all this increase in fertilizer will ultimately end up. cloud formation and their temperature regulation may also provide indicators of fertilizer accumulation if changes in ocean color do not. We can not double the available nitrogen and vastly increase potassium and phosphorus along with co2 as you note without changing the dynamics of a system and they will move toward a new equilibrium which may account for the missing co2.
Is there anything you've written or read that can help me understand the potential for disturbed ecosystems to reach a point where their function approximates that of what they might have achieved when undisturbed.
In other words, if we fail to figure out how to conserve undisturbed ecosystems, what are the chances we'll be able to steward what we have left towards a state that is at least increasingly positive for life?
David, thank you for this key question. When a natural ecosystem is disturbed—by fire, windfall, or other factors—the process of ecological succession begins. A non-random sequence of species, already present in small numbers (or as seeds and spores) in the undisturbed ecosystem, rapidly colonizes the impaired area and gradually restores it. Their role is similar to that of the immune system, where immune cells multiply rapidly to repair the body after an infection.
In the boreal forest ecosystem, which I know best, heavily burned areas are often first colonized by green moss. This is followed by lichens and herbs, then bushes and early successional trees like birch, before the ecosystem ultimately returns to its climax species—the dominant trees of the original, undisturbed forest.
Ecosystems that can still initiate succession after a disturbance are self-sustaining. Those that cannot are effectively lost (degraded).
One example of such degradation is described as a "landscape trap" (searchable on Google Scholar). This occurs when repeated logging and increased susceptibility to fires, caused by logging, eliminate an ecosystem’s ability to recover, preventing natural succession from taking place.
A very timely post - for us living in Zambia! On Saturday social media was informed that we had until today (Monday) to lodge our views on an old (1968) proposal to divert water from the Luapula River (which flows north into the Congo River) to cross the "pedicle" (that bit of DRC which almost divides Zambia in half) into the Kafue river, which flows south into the Zambezi. The extra water would generate enough electricity (in the 3 power stations on the Kafue) to pump the water across, and leave a surplus of power and water (to be used for irrigation). Someone proposed that, instead, we should simply move all our agriculture up there! Please take a moment to look at Zambia on Google Earth - note the mustard yellow areas in the South, East and (increasingly) the center of Zambia. These are areas where the woodland has been cleared for agriculture (and charcoal) and where the rivers flow chocolate brown in summer (through soil erosion) but stop flowing withing a few weeks of the end of our rainy season. (Note the yellow area to the west of the country is not due to deforestation, but is the large Zambezi floodplain. There is also a significant floodplain on the Kafue.) Should we move any agriculture up into the northern part of the country it won't be long before their rivers flow muddy and seasonally. The flow in the Kafue and Zambezi will continue to decline (currently only 50% of their peak flow in the 1970s - when tree cover was at it's peak in the region). So, I see Zambia's (and indeed southern Africa's) challenge is how to preserve our remaining woodland, while improving our farming systems to not only produce more food (we expect 200m more people by 2040) but in such a way that our crop land can imitate Anastassia's boreal and other old growth forests as closely as possible, so that even our agricultural land can help provide the ecological services of helping bring in the rain and sink the Carbon. Please look at www.radio4pasa.com/Bring-back-the-rains (and the Farmers Handbook page) as the way I am thinking we could improve our farming in Southern Africa to be both more Profitable and more Sustainable. I would appreciate feedback and ideas.
Sun light driving photosynthesis is not the only energy source for making carbohydrates out of CO2. Methane and sulfur are also energy sources for life on Earth.
Methane is metabolized by Archaebacteria and methanogenic archaea, which feed on decaying plants in oxygen-poor wetlands, permafrost, cattle ranches, garbage dumps, and other environments. The amount of methane released by microbes is rising as climate change alters conditions, for example melting permafrost.
Methanotrophs represent one of Earth’s most vital methane sinks. They grow by metabolizing into proteins and sugars up to 90% of the methane produced in wetlands and atmospheric methane in soils.
How are methane-eating microbes responding to climate change? Are they physiologically adjusting to temperature changes and other stressors to influence the amount of methane entering the atmosphere?
Researchers recently went to a bog, removed the top layer, and brought methane-eating bacteria back to the laboratory. Culturing methanotrophs is a hazardous undertaking because these bacteria require an enormous amount of oxygen and hydrogen. The amount of oxygen is often less than optimal for bacteria because scientists are concerned about their safety due to the risk of explosions.
Three methane-eating bacteria from the genus Methylobacterwere collected from the bog. These were common methanotrophs found in wetlands worldwide. Under varying conditions, researchers observed the amount of methane consumed, the growth rate of the bacteria, and the internal changes within the cells. The quantity of methane the bacteria consumed depended on their condition. The bacteria consumed more methane when the temperatures were either warmer or cooler than they were accustomed to, because they had to expend a lot of energy to repair issues in their cells.
At 60 degrees Fahrenheit, one species of bacteria consumed a significant amount of methane to compensate for the less-than-ideal temperature. Methane consumption decreased by 30 percent when the temperature was increased to 70 degrees, yet the growth rate remained consistent. Researchers observed that as the temperature decreased, the bacteria consumed more methane and produced additional ribosomes to metabolize more proteins. The increase in protein production allowed the bacteria to maintain their processing speed even when the temperature dropped. Methane consumption increased with diminishing temperatures.
Some bacteria increased methane uptake when the environment became too warm. As the molecules increased their motion, more methane was used to repair damage or increase the rigidity of the cell wall.
How methane-eating bacteria will affect global methane emissions in the future remains as murky as the bog muck from which these methanotrophs came. The study found that depending on the type of methane-eating bacteria that dominates the ecosystem will indicate the reaction when the temperature rises. The good news is that methanotrophs are diverse in every ecosystem. The one most fit for the situation (or needing the most repairs) will increase methane consumption. Fortunately, there is another domain of microbes eating methane.
Archaea, a domain of primitive prokaryotes distinct from bacteria, derives its name from the Greek word meaning old and primitive. These single-celled organisms produce methane through anaerobic cellular respiration. Conversely, Methanoperedens are archaea that decompose methane in soils, groundwater, and the atmosphere to form complex carbohydrates.
Researchers recently sampled Methanoperedens from underground soil, aquifers, and riverbeds. They were surprised to find packets of DNA within single-celled organisms, known as extrachromosomal elements, that transfer genes often viaviruses between bacteria and archaea. These packets allow microbes to have on-hand beneficial genes from neighboring organisms.
The extra-chromosomal elements are a relatively large conglomeration of diverse genomes assimilated from many organisms held within one organism and named “Borgs” after the assimilation of many planet parts in Star Trek.
The archaea cellSun light driving photosynthesis is not the only energy source for making carbohydrates out of CO2. Methane and sulfur are also energy sources for life on Earth.
Methane is metabolized by Archaebacteria and methanogenic archaea, which feed on decaying plants in oxygen-poor wetlands, permafrost, cattle ranches, garbage dumps, and other environments. The amount of methane released by microbes is rising as climate change alters conditions, for example melting permafrost.
Methanotrophs represent one of Earth’s most vital methane sinks. They grow by metabolizing into proteins and sugars up to 90% of the methane produced in wetlands and atmospheric methane in soils.
How are methane-eating microbes responding to climate change? Are they physiologically adjusting to temperature changes and other stressors to influence the amount of methane entering the atmosphere?
Researchers recently went to a bog, removed the top layer, and brought methane-eating bacteria back to the laboratory. Culturing methanotrophs is a hazardous undertaking because these bacteria require an enormous amount of oxygen and hydrogen. The amount of oxygen is often less than optimal for bacteria because scientists are concerned about their safety due to the risk of explosions.
Three methane-eating bacteria from the genus Methylobacterwere collected from the bog. These were common methanotrophs found in wetlands worldwide. Under varying conditions, researchers observed the amount of methane consumed, the growth rate of the bacteria, and the internal changes within the cells. The quantity of methane the bacteria consumed depended on their condition. The bacteria consumed more methane when the temperatures were either warmer or cooler than they were accustomed to, because they had to expend a lot of energy to repair issues in their cells.
At 60 degrees Fahrenheit, one species of bacteria consumed a significant amount of methane to compensate for the less-than-ideal temperature. Methane consumption decreased by 30 percent when the temperature was increased to 70 degrees, yet the growth rate remained consistent. Researchers observed that as the temperature decreased, the bacteria consumed more methane and produced additional ribosomes to metabolize more proteins. The increase in protein production allowed the bacteria to maintain their processing speed even when the temperature dropped. Methane consumption increased with diminishing temperatures.
Some bacteria increased methane uptake when the environment became too warm. As the molecules increased their motion, more methane was used to repair damage or increase the rigidity of the cell wall.
How methane-eating bacteria will affect global methane emissions in the future remains as murky as the bog muck from which these methanotrophs came. The study found that depending on the type of methane-eating bacteria that dominates the ecosystem will indicate the reaction when the temperature rises. The good news is that methanotrophs are diverse in every ecosystem. The one most fit for the situation (or needing the most repairs) will increase methane consumption. Fortunately, there is another domain of microbes eating methane.
Archaea, a domain of primitive prokaryotes distinct from bacteria, derives its name from the Greek word meaning old and primitive. These single-celled organisms produce methane through anaerobic cellular respiration. Conversely, Methanoperedens are archaea that decompose methane in soils, groundwater, and the atmosphere to form complex carbohydrates.
Researchers recently sampled Methanoperedens from underground soil, aquifers, and riverbeds. They were surprised to find packets of DNA within single-celled organisms, known as extrachromosomal elements, that transfer genes often viaviruses between bacteria and archaea. These packets allow microbes to have on-hand beneficial genes from neighboring organisms.
The extra-chromosomal elements are a relatively large conglomeration of diverse genomes assimilated from many organisms held within one organism and named “Borgs” after the assimilation of many planet parts in Star Trek.
The archaea cell already consumes methane. It possesses an arsenal of genetic elements to draw from, allowing the cell to have a higher capacity should conditions change. Said the lead author, “It basically creates a condition for methane consumption on steroids, if you will.”
Evidence indicates that whenever methane emissions rise, bacteria and archaea are poised to increase their methane consumption. They take the energy of methane to combine carbon dioxide and water into carbohydrates, sequestering carbon at the base of the ecosystem’s food pyramid. We can tip the balance from too much industrialization towards more natural environments, such as wetlands, grasslands, fields, forests, and natural river-beds.
Thank you, John, for your appreciation. Walking through all this (self-)gaslighting sometimes feels lonely and insecure, however, at the same time intellectually rewarding as in any good detective story.
I pondered this in my sleep and woke up wondering about how much methane clathrate is being produced. It is hard to study because it accumulates in the deepest and coldest ocean waters. https://en.wikipedia.org/wiki/Methane_clathrate
The science indicates that 90% of the methane released from melting permafrost is used as energy by microbes to manufacture sugars and other carbohydrates by drawing much CO2 out of the air. Gigatons is a big number. However, there is a lot of permafrost, bogs, wetlands, river bottoms and healthy soils where these microbes are thriving and living carbon-rich lives off of methane. To reverse climate change by increasing carbon drawdown, we need only give methane-eating microbes more real-estate to thrive.
A very interesting read, both hopeful and humbling. I am far from a specialist, and enjoyed it very much.
Thank you!
Thank you for this, Anastassia. If I understand you correctly, you are saying CO2 fertilization cannot account for the missing carbon sink because what is gained in photosynthesis is later released as part of decomposition, thus a net zero. However, in healthy systems, soil microbes are able to draw a certain percentage of that carbon into the soil for long term storage.
I suppose a similar thing happens in the ocean, in which carbon is calcified as marine shells.
Is this what Bar-on et al. mean by non-living pools, pools of inorganic carbon in soils and the ocean created by living processes?
I've noticed your observation about the scientific attitude to the carbon sink. There seems to be a desire to minimize the role of life in the system, to keep the entire matter purely physical. I don't understand this motivation, but it seems deeply ingrained. I think of Copernicus and the Church. The Church was willing to accept Copernicus' findings in a scientific sense, but not in a metaphorical sense. "Fine, the universe is not heliocentric, but it still, in our minds and cultures, will revolve around us." We seem determined to not acknowledge the metaphorical implications of biotic regulation, without which our bodies, or any other living thing for that matter, including the climate, can not function. Meanwhile, the destruction continues, which is perhaps the point.
Spot on with your last paragraph Rob
Rob, the result of Bar-on et al. is that carbon did not accumulate in trees. Fullstop. This does mean however that it accumulated somewhere else, in soil and/or dissolved organic matter in the ocean.
CO2 fertilization, by definition, means that photosynthesis is carbon-limited and increases with increasing concentration of atmospheric carbon dioxide. This does not explain the sink, because for there to be a sink, there must be a correlated response of autotrophs and heterotrophs, with the latter refraining from consuming the extra food synthesized by plants. This reaction of heterotrophs has nothing to do with any "fertilization".
Thanks Anastassia, great article.
As Rob mentioned below, the missing sink could be explained by the "Liquid Carbon Pathway".
Plants exude up to 50% or more of the carbohydrates they produce through photosynthesis into the soil via their root hairs to feed bacteria and fungi.
These microbes use it as a food source and fix most of it as stable carbon molecules in the soil. In return they provide nutrients and water to the plants, otherwise unavailable. It's the rhisophagy cycle.
~50% of the CO2 plants absorb from the atmosphere is fixed in the soil through root exudates via microbes. But only if the soil ecosystem is healthy and alive with microbes and higher order soil fauna (mites, worme etc).
Dr Christine Jones, soil ecologist coined the term "Liquid Carbon Pathway"
Professor James White has some fascinating research and imagery showing bacteria interacting with plant root hairs, worth a look.
Grasses are the only plants that exude 50% of photosynthesized carbohydrates to build soils. Most plants exude about one third. This is why grasses are excellent pioneer plants preparing the soil for others. Silviopasture, grasses and trees together is the best carbon sink, better than just grass or trees.
"Grasses are the only plants that exude 50% of their photosynthesized carbohydrates to build soils. Most plants exude about one-third."
Rob, thank you for this comment.
Let's consider this statement in light of the law of matter conservation. The preindustrial atmosphere contained approximately 600 gigatons of carbon, while the rate of photosynthesis on land was around 50 gigatons of carbon per year. If plants exuded 30% of their carbohydrates to build soil—about 15 gigatons of carbon per year—and heterotrophs did not decompose this exudate but instead allowed it to accumulate, ALL atmospheric carbon would be depleted in just 40 years.
Clearly, this does not happen. CO₂ concentrations remain relatively stable over extended periods because, in a healthy ecosystem in the absence of disturbances, synthesis and decomposition are closely balanced.
Now, if we aim to understand which ecosystems can most effectively respond to carbon disturbances, we must consider the community's response as a whole. A system where plants exude 50% of their carbohydrates to the soil but are coupled with heterotrophs that rapidly decompose this input could have a smaller compensatory impact than one where plants exude less but are paired with heterotrophs that allow more of this exudate to persist in the soil.
Just one example of ecosystem complexity thinking.
Thank you, Steve. When aerobic microbes use something as a food source, they decompose organic carbon, say (CH2O)n, into CO2 and water. When you say that they fix most of it "as stable carbon molecules" in soil, this means that they do not eat them up fully, but store in an inactive organic form. It still remains a source of energy that some other microbes could use but they choose not to. As I quoted in the post, "the turnover time of organic compounds in soil is mostly determined not by their chemical composition but by functioning of the entire ecological community, plants and soil biota included", with a reference to Schmidt et al. 2011, which is in my opinion a great article titled "Persistence of soil organic matter as an ecosystem property", Nature https://doi.org/10.1038/nature10386
Hi Anastassia, thanks for the link, looks great, I'll try to get access! This is such an interesting space, so much to discover that's critical to our future.
My mind keeps going back to the grasslands / rangelands / prairies in North America, Australia particularly, and the stories of 3m deep carbon rich soils full of diversity and life. Soils which are now dead with almost no carbon or life.
And the stories of people now managing their land and animals who are starting to rebuild their soil carbon and ecosystem function. Heading towards those original deep rich fertile soils.
I can't help but think that healthy ecosystems must have a process that results in carbon building up in the soil naturally. Where more is retained in the ground than decomposed and released.
I wonder if it could be related to soil depth, and if most active microbial activity is in the top layers of soil profiles generally? As you go deeper fewer decomposing microbes eat the carbon??
Maybe arbuscular mycorrhizal fungi deposit their glomalin deeper than the majority of active decomposers. Maybe someone has done this research.
Another question is if carbon does build up in soil, how does it not just keep going as you mention above in your comment to Rob, and deplete all atmospheric carbon? Or does it keep going and globally there is balance from other processes that release carbon?? Maybe 3m deep is the limit? Who knows!!??
Hi Steve nothing lives forever and I would think as soon as an organism or plant dies the readily available nutrients would be reused carbon included. As to the depth question I would assume that the other nutrients would be the limiting factors to the build up of total biomass both above and below ground, this could be seen in areas of high nutrient vs areas of low all others being equal. NZ is a good example with a close mixture of volcanic, basalt and clay topsoil and the differing growth and soil depth found.
I wrote in response to a previous article the notion that the mining and manufacturing of fertilizer and irrigation has had an impact on the equilibrium of these static cycles and show through graph interpretation the result temperature regulation by feeding the biotic system. In my mind the movement of the main components of organic growth through waste, surface runoff, groundwater and the air, both fire and natural recycling of this would change the static dynamics of every impacted system ( I would assume most of the planet). It is right to concentrate on the ocean as the missing sink as this is where all this increase in fertilizer will ultimately end up. cloud formation and their temperature regulation may also provide indicators of fertilizer accumulation if changes in ocean color do not. We can not double the available nitrogen and vastly increase potassium and phosphorus along with co2 as you note without changing the dynamics of a system and they will move toward a new equilibrium which may account for the missing co2.
Hi Anastassia,
Is there anything you've written or read that can help me understand the potential for disturbed ecosystems to reach a point where their function approximates that of what they might have achieved when undisturbed.
In other words, if we fail to figure out how to conserve undisturbed ecosystems, what are the chances we'll be able to steward what we have left towards a state that is at least increasingly positive for life?
David, thank you for this key question. When a natural ecosystem is disturbed—by fire, windfall, or other factors—the process of ecological succession begins. A non-random sequence of species, already present in small numbers (or as seeds and spores) in the undisturbed ecosystem, rapidly colonizes the impaired area and gradually restores it. Their role is similar to that of the immune system, where immune cells multiply rapidly to repair the body after an infection.
In the boreal forest ecosystem, which I know best, heavily burned areas are often first colonized by green moss. This is followed by lichens and herbs, then bushes and early successional trees like birch, before the ecosystem ultimately returns to its climax species—the dominant trees of the original, undisturbed forest.
Ecosystems that can still initiate succession after a disturbance are self-sustaining. Those that cannot are effectively lost (degraded).
One example of such degradation is described as a "landscape trap" (searchable on Google Scholar). This occurs when repeated logging and increased susceptibility to fires, caused by logging, eliminate an ecosystem’s ability to recover, preventing natural succession from taking place.
A very timely post - for us living in Zambia! On Saturday social media was informed that we had until today (Monday) to lodge our views on an old (1968) proposal to divert water from the Luapula River (which flows north into the Congo River) to cross the "pedicle" (that bit of DRC which almost divides Zambia in half) into the Kafue river, which flows south into the Zambezi. The extra water would generate enough electricity (in the 3 power stations on the Kafue) to pump the water across, and leave a surplus of power and water (to be used for irrigation). Someone proposed that, instead, we should simply move all our agriculture up there! Please take a moment to look at Zambia on Google Earth - note the mustard yellow areas in the South, East and (increasingly) the center of Zambia. These are areas where the woodland has been cleared for agriculture (and charcoal) and where the rivers flow chocolate brown in summer (through soil erosion) but stop flowing withing a few weeks of the end of our rainy season. (Note the yellow area to the west of the country is not due to deforestation, but is the large Zambezi floodplain. There is also a significant floodplain on the Kafue.) Should we move any agriculture up into the northern part of the country it won't be long before their rivers flow muddy and seasonally. The flow in the Kafue and Zambezi will continue to decline (currently only 50% of their peak flow in the 1970s - when tree cover was at it's peak in the region). So, I see Zambia's (and indeed southern Africa's) challenge is how to preserve our remaining woodland, while improving our farming systems to not only produce more food (we expect 200m more people by 2040) but in such a way that our crop land can imitate Anastassia's boreal and other old growth forests as closely as possible, so that even our agricultural land can help provide the ecological services of helping bring in the rain and sink the Carbon. Please look at www.radio4pasa.com/Bring-back-the-rains (and the Farmers Handbook page) as the way I am thinking we could improve our farming in Southern Africa to be both more Profitable and more Sustainable. I would appreciate feedback and ideas.
Sun light driving photosynthesis is not the only energy source for making carbohydrates out of CO2. Methane and sulfur are also energy sources for life on Earth.
Methane is metabolized by Archaebacteria and methanogenic archaea, which feed on decaying plants in oxygen-poor wetlands, permafrost, cattle ranches, garbage dumps, and other environments. The amount of methane released by microbes is rising as climate change alters conditions, for example melting permafrost.
Methanotrophs represent one of Earth’s most vital methane sinks. They grow by metabolizing into proteins and sugars up to 90% of the methane produced in wetlands and atmospheric methane in soils.
How are methane-eating microbes responding to climate change? Are they physiologically adjusting to temperature changes and other stressors to influence the amount of methane entering the atmosphere?
Researchers recently went to a bog, removed the top layer, and brought methane-eating bacteria back to the laboratory. Culturing methanotrophs is a hazardous undertaking because these bacteria require an enormous amount of oxygen and hydrogen. The amount of oxygen is often less than optimal for bacteria because scientists are concerned about their safety due to the risk of explosions.
Three methane-eating bacteria from the genus Methylobacterwere collected from the bog. These were common methanotrophs found in wetlands worldwide. Under varying conditions, researchers observed the amount of methane consumed, the growth rate of the bacteria, and the internal changes within the cells. The quantity of methane the bacteria consumed depended on their condition. The bacteria consumed more methane when the temperatures were either warmer or cooler than they were accustomed to, because they had to expend a lot of energy to repair issues in their cells.
At 60 degrees Fahrenheit, one species of bacteria consumed a significant amount of methane to compensate for the less-than-ideal temperature. Methane consumption decreased by 30 percent when the temperature was increased to 70 degrees, yet the growth rate remained consistent. Researchers observed that as the temperature decreased, the bacteria consumed more methane and produced additional ribosomes to metabolize more proteins. The increase in protein production allowed the bacteria to maintain their processing speed even when the temperature dropped. Methane consumption increased with diminishing temperatures.
Some bacteria increased methane uptake when the environment became too warm. As the molecules increased their motion, more methane was used to repair damage or increase the rigidity of the cell wall.
How methane-eating bacteria will affect global methane emissions in the future remains as murky as the bog muck from which these methanotrophs came. The study found that depending on the type of methane-eating bacteria that dominates the ecosystem will indicate the reaction when the temperature rises. The good news is that methanotrophs are diverse in every ecosystem. The one most fit for the situation (or needing the most repairs) will increase methane consumption. Fortunately, there is another domain of microbes eating methane.
Archaea, a domain of primitive prokaryotes distinct from bacteria, derives its name from the Greek word meaning old and primitive. These single-celled organisms produce methane through anaerobic cellular respiration. Conversely, Methanoperedens are archaea that decompose methane in soils, groundwater, and the atmosphere to form complex carbohydrates.
Researchers recently sampled Methanoperedens from underground soil, aquifers, and riverbeds. They were surprised to find packets of DNA within single-celled organisms, known as extrachromosomal elements, that transfer genes often viaviruses between bacteria and archaea. These packets allow microbes to have on-hand beneficial genes from neighboring organisms.
The extra-chromosomal elements are a relatively large conglomeration of diverse genomes assimilated from many organisms held within one organism and named “Borgs” after the assimilation of many planet parts in Star Trek.
The archaea cellSun light driving photosynthesis is not the only energy source for making carbohydrates out of CO2. Methane and sulfur are also energy sources for life on Earth.
Methane is metabolized by Archaebacteria and methanogenic archaea, which feed on decaying plants in oxygen-poor wetlands, permafrost, cattle ranches, garbage dumps, and other environments. The amount of methane released by microbes is rising as climate change alters conditions, for example melting permafrost.
Methanotrophs represent one of Earth’s most vital methane sinks. They grow by metabolizing into proteins and sugars up to 90% of the methane produced in wetlands and atmospheric methane in soils.
How are methane-eating microbes responding to climate change? Are they physiologically adjusting to temperature changes and other stressors to influence the amount of methane entering the atmosphere?
Researchers recently went to a bog, removed the top layer, and brought methane-eating bacteria back to the laboratory. Culturing methanotrophs is a hazardous undertaking because these bacteria require an enormous amount of oxygen and hydrogen. The amount of oxygen is often less than optimal for bacteria because scientists are concerned about their safety due to the risk of explosions.
Three methane-eating bacteria from the genus Methylobacterwere collected from the bog. These were common methanotrophs found in wetlands worldwide. Under varying conditions, researchers observed the amount of methane consumed, the growth rate of the bacteria, and the internal changes within the cells. The quantity of methane the bacteria consumed depended on their condition. The bacteria consumed more methane when the temperatures were either warmer or cooler than they were accustomed to, because they had to expend a lot of energy to repair issues in their cells.
At 60 degrees Fahrenheit, one species of bacteria consumed a significant amount of methane to compensate for the less-than-ideal temperature. Methane consumption decreased by 30 percent when the temperature was increased to 70 degrees, yet the growth rate remained consistent. Researchers observed that as the temperature decreased, the bacteria consumed more methane and produced additional ribosomes to metabolize more proteins. The increase in protein production allowed the bacteria to maintain their processing speed even when the temperature dropped. Methane consumption increased with diminishing temperatures.
Some bacteria increased methane uptake when the environment became too warm. As the molecules increased their motion, more methane was used to repair damage or increase the rigidity of the cell wall.
How methane-eating bacteria will affect global methane emissions in the future remains as murky as the bog muck from which these methanotrophs came. The study found that depending on the type of methane-eating bacteria that dominates the ecosystem will indicate the reaction when the temperature rises. The good news is that methanotrophs are diverse in every ecosystem. The one most fit for the situation (or needing the most repairs) will increase methane consumption. Fortunately, there is another domain of microbes eating methane.
Archaea, a domain of primitive prokaryotes distinct from bacteria, derives its name from the Greek word meaning old and primitive. These single-celled organisms produce methane through anaerobic cellular respiration. Conversely, Methanoperedens are archaea that decompose methane in soils, groundwater, and the atmosphere to form complex carbohydrates.
Researchers recently sampled Methanoperedens from underground soil, aquifers, and riverbeds. They were surprised to find packets of DNA within single-celled organisms, known as extrachromosomal elements, that transfer genes often viaviruses between bacteria and archaea. These packets allow microbes to have on-hand beneficial genes from neighboring organisms.
The extra-chromosomal elements are a relatively large conglomeration of diverse genomes assimilated from many organisms held within one organism and named “Borgs” after the assimilation of many planet parts in Star Trek.
The archaea cell already consumes methane. It possesses an arsenal of genetic elements to draw from, allowing the cell to have a higher capacity should conditions change. Said the lead author, “It basically creates a condition for methane consumption on steroids, if you will.”
Evidence indicates that whenever methane emissions rise, bacteria and archaea are poised to increase their methane consumption. They take the energy of methane to combine carbon dioxide and water into carbohydrates, sequestering carbon at the base of the ecosystem’s food pyramid. We can tip the balance from too much industrialization towards more natural environments, such as wetlands, grasslands, fields, forests, and natural river-beds.
Thank you, Rob! Extremely interesting. And complex!
https://www.sciencenorway.no/bacteria-climate-methane/these-small-bacteria-eat-huge-amounts-of-methane-how-will-they-respond-to-climate-change/2150152#:~:text=%E2%80%9CYou%20can%20go%20to%20a%20bog
https://www.nature.com/articles/s41396-023-01363-7
https://www.sciencenorway.no/bacteria-climate-methane/these-small-bacteria-eat-huge-amounts-of-methane-how-will-they-respond-to-climate-change/2150152#:~:text=%E2%80%9CYou%20can%20go%20to%20a%20bog
https://innovativegenomics.org/news/borg-assimilate-dna/
Thank you for the detective work Anastassia, and contributors to comments.
Thank you, John, for your appreciation. Walking through all this (self-)gaslighting sometimes feels lonely and insecure, however, at the same time intellectually rewarding as in any good detective story.
I remain prayerfully hopeful for Schrodinger's Carbon Sink.
I pondered this in my sleep and woke up wondering about how much methane clathrate is being produced. It is hard to study because it accumulates in the deepest and coldest ocean waters. https://en.wikipedia.org/wiki/Methane_clathrate
The science indicates that 90% of the methane released from melting permafrost is used as energy by microbes to manufacture sugars and other carbohydrates by drawing much CO2 out of the air. Gigatons is a big number. However, there is a lot of permafrost, bogs, wetlands, river bottoms and healthy soils where these microbes are thriving and living carbon-rich lives off of methane. To reverse climate change by increasing carbon drawdown, we need only give methane-eating microbes more real-estate to thrive.