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DrTskoul

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Re: Carbon Cycle
« Reply #500 on: July 25, 2019, 12:00:11 PM »
Thanks Vox!

This looks like another chunk out of the budget?

And this makes me wonder about how climate models actually interact with soils...

They interact with as much data and knowledge we have...which means not a lot ....

bligh8

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Re: Carbon Cycle
« Reply #501 on: August 18, 2019, 05:10:42 PM »
Ice sheets matter for the global carbon cycle

J. L. Wadham, J. R. Hawkings, L. Tarasov, L. J. Gregoire, R. G. M. Spencer, M. Gutjahr, A. Ridgwell & K. E. Kohfeld .. open access, nice paper

Abstract

The cycling of carbon on Earth exerts a fundamental influence upon the greenhouse gas content of the atmosphere, and hence global climate over millennia. Until recently, ice sheets were viewed as inert components of this cycle and largely disregarded in global models. Research in the past decade has transformed this view, demonstrating the existence of uniquely adapted microbial communities, high rates of biogeochemical/physical weathering in ice sheets and storage and cycling of organic carbon (>104 Pg C) and nutrients. Here we assess the active role of ice sheets in the global carbon cycle and potential ramifications of enhanced melt and ice discharge in a warming world.

" Only in the last 15 years have glacial systems started to be considered as active cyclers of carbon, arising from the discovery that they include a range of aquatic environments4 which host abundant and diverse populations of microorganisms5 and are hot spots for biogeochemical weathering6. These processes create the potential for ice sheets to directly or indirectly impact the global carbon cycle (Fig. 1). Direct impacts include the release of greenhouse gases (carbon dioxide, CO2 and methane, CH4) during the microbial respiration of organic matter (OM) stored within ice sheets. Examples of indirect impacts include the fertilisation of downstream ecosystems, promoted by either the release of nutrient-rich glacial meltwaters7,8,9 or by subglacial meltwater-induced upwelling of nutrient replete marine water at tidewater glacier margins10,11,12,13,14. Ocean fertilisation by glaciers may be accompanied by significant CO2 drawdown by phytoplankton, intensifying the biological pump15,16."

kassy

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Re: Carbon Cycle
« Reply #502 on: August 18, 2019, 06:19:26 PM »
Þetta minnismerki er til vitnis um að við vitum hvað er að gerast og hvað þarf að gera. Aðeins þú veist hvort við gerðum eitthvað.

bligh8

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Re: Carbon Cycle
« Reply #503 on: August 19, 2019, 04:17:21 PM »
nice response .. and, Your Very Welcome

rboyd

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Re: Carbon Cycle
« Reply #504 on: August 29, 2019, 07:55:03 PM »
Nitrogen and phosphorus constrain the CO2 fertilization of global plant biomass

Seems to show that the increased uptake of CO2 by plant matter at increased levels of atmospheric CO2 will continue, even in the face of nutrient limits proposed by other research.

Abstract:

Elevated CO2 (eCO2) experiments provide critical information to quantify the effects of rising CO2 on vegetation. Many eCO2 experiments suggest that nutrient limitations modulate the local magnitude of the eCO2 effect on plant biomass, but the global extent of these limitations has not been empirically quantified, complicating projections of the capacity of plants to take up CO2. Here, we present a data-driven global quantification of the eCO2 effect on biomass based on 138 eCO2 experiments. The strength of CO2 fertilization is primarily driven by nitrogen (N) in ~65% of global vegetation and by phosphorus (P) in ~25% of global vegetation, with N- or P-limitation modulated by mycorrhizal association. Our approach suggests that CO2 levels expected by 2100 can potentially enhance plant biomass by 12 ± 3% above current values, equivalent to 59 ± 13 PgC. The global-scale response to eCO2 we derive from experiments is similar to past changes in greenness and biomass with rising CO2, suggesting that CO2 will continue to stimulate plant biomass in the future despite the constraining effect of soil nutrients. Our research reconciles conflicting evidence on CO2 fertilization across scales and provides an empirical estimate of the biomass sensitivity to eCO2 that may help to constrain climate projections.

https://www.nature.com/articles/s41558-019-0545-2

A good summary from Science Daily.

Quote
The results show trees and plants could remove six years of current emissions by 2100, but only if no further deforestation occurs.

The study, led by Stanford University and the Autonomous University of Barcelona, and including Imperial College London researchers, is published in Nature Climate Change.

As plants grow they take in carbon dioxide (CO2) from the air. As CO2 concentrations in the air rise due to human-caused emissions, researchers have suggested that plants will be able to grow larger, and therefore take in more CO2.

However, plant growth is not only due to CO2 concentrations, but relies on the availability of nutrients in the soil, particularly nitrogen and phosphorus. If the plants can't get enough nutrients, they will not grow more despite higher CO2 concentrations.

Hundreds of experiments over the past few decades have tried to determine how much extra CO2 plants can take in before the availability of nutrients becomes limiting, but many have come up with different answers.

Now, a group of 32 scientists from 13 countries have analysed all the previous experiments to come up with a global estimate of plants' ability to take in CO2.

Their results show that globally plants can increase their biomass (organic material) by 12 percent when exposed to concentrations of CO2 predicted for the year 2100.

This extra growth would draw enough CO2 from the atmosphere to cancel out six years of current human-induced emissions.

However, the result is based on plant and forest cover remaining at current levels -- so no further deforestation occurs.

Lead author Dr César Terrer, now at Stanford University's School of Earth, Energy & Environmental Sciences, initiated the project while at Imperial College London. He said: "Keeping fossil fuels in the ground is the best way to limit further warming. But stopping deforestation and preserving forests so they can grow more is our next-best solution."

Several individual experiments, such as fumigating forests with elevated levels of carbon dioxide and growing plants in gas-filled chambers, have provided critical data but no definitive answer globally.

To more accurately predict the capacity of trees and plants to sequester CO2 in the future, the researchers synthesized data from all elevated carbon dioxide experiments conducted so far, in grassland, shrubland, cropland and forest systems.

Using statistical methods, machine-learning, models and satellite data, they quantified how much soil nutrients and climate factors limit the ability of plants and trees to absorb extra CO2.

They found that tropical forests had the greatest capacity for growth and increased CO2 uptake, such as those in the Amazon, Congo and Indonesia.

Dr Terrer said: "We have already witnessed indiscriminate logging in pristine tropical forests, which are the largest reservoirs of biomass in the planet. We stand to lose a tremendously important tool to limit global warming."

The study also shows how plants' and trees' ability to absorb extra CO2 relies on their association with different fungi in their roots, which help them get extra soil nutrients.

The results of the study will be valuable to scientists building models of future climate change and the impact of reforestation or deforestation.

https://www.sciencedaily.com/releases/2019/08/190820130929.htm




kassy

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Re: Carbon Cycle
« Reply #505 on: August 29, 2019, 09:10:23 PM »
Seems to show that the increased uptake of CO2 by plant matter at increased levels of atmospheric CO2 will continue, even in the face of nutrient limits proposed by other research.

But is there enough water vapour?
https://www.carbonbrief.org/rising-water-stress-could-counteract-global-green-study-says
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rboyd

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Re: Carbon Cycle
« Reply #506 on: August 29, 2019, 10:35:32 PM »
Seems to show that the increased uptake of CO2 by plant matter at increased levels of atmospheric CO2 will continue, even in the face of nutrient limits proposed by other research.

But is there enough water vapour?
https://www.carbonbrief.org/rising-water-stress-could-counteract-global-green-study-says

And there was me thinking that for once I would be posting something positive, oh well ... back to the accelerating emissions, increasing feedbacks, underestimated/ignored feedbacks, lack of any real government action etc. etc.

sidd

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Re: Carbon Cycle
« Reply #507 on: September 04, 2019, 07:59:26 AM »
This is interesting: bigger CO2 uptake than thought in southern ocean

doi: 10.1038/s41558-019-0562-1


"This implies a strengthening of the carbon sink over more than two decades in the southern region during the austral summer."

"Interestingly, the decrease in DIC is in contrast to the increase expected from anthropogenic CO2 accumulation"

"leave no doubt that the summer ocean carbon sink has increased rapidly since 1993 in the investigated region, driven by an increase in phytoplankton production, particularly from diatoms, related to ocean stratification."

sidd

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Re: Carbon Cycle
« Reply #508 on: September 07, 2019, 02:23:34 AM »
Ocean acidification could reduce the transport of carbon to the bottom of the ocean and carbon absorption capacity of the ocean:

https://www.eurekalert.org/pub_releases/2019-08/uots-ntf082319.php

"The oceans act as a carbon sink and have already absorbed more than 40% of anthropogenic carbon emissions. The majority of this CO2 has been taken up by the Southern Ocean making these waters hotspots of ocean acidification (OA).
Lead author of the paper published in Nature Climate Change, Dr Katherina Petrou from the University of Technology Sydney, said that although changes in ocean pH have been shown to impact marine calcifying organisms, the consequences for non-calcifying marine phytoplankton are less clear.
"Previous studies reported a range of responses to OA [in phytoplankton] yet rarely considered how environmental pH shifts might affect silicification rates in diatoms," she says.
"Diatoms are unique phytoplankton in that they need silicic acid to produce silica cell walls. Under the microscope they look like beautiful glass jewellery boxes, but importantly, this dense, glass-like armour promotes sinking, which makes diatoms an important conduit for transport of carbon to the deep ocean where it can be stored for millennia."
Diatoms are responsible for around 40% of ocean productivity which means they play a major role in supporting marine food webs, sustaining life for millions of creatures, including humans.
The research was carried out the Australian Antarctic base, Davis station, by a team of scientists from the University of Technology Sydney (UTS), Southern Cross University (SCU), the Australian Antarctic Division (AAD) and the University of Tasmania. Using large 650 L experimental tanks, a temperature controlled 40-foot container and natural coastal water, their research was designed to investigate the effects of predicted future changes in ocean acidity on the community structure of the Antarctic phytoplankton.
"We were alarmed to find that diatoms were so negatively affected, with some species likely to have diminished silica production before the end of this century," says Dr Petrou.
In the context of global climate change, these findings are important because they reveal that OA can notonly alter phytoplankton community composition, but also reduce diatom ballast (sinking ability), adds SCU based Kai Schulz. Loss of silica production and thus ballast could mean that fewer diatoms end up on the ocean floor, resulting in less atmospheric CO2 being removed from our atmosphere and transported for storage in the deep ocean.
"The only genuine way to circumvent this outcome, is to cut our greenhouse gas emissions and limit the acidification of our oceans," the researchers say. "


Article in Nature Climate Change is under a paywall, maybe someone would have access?

nanning

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Re: Carbon Cycle
« Reply #509 on: September 07, 2019, 05:41:13 AM »
<snip>
Article in Nature Climate Change is under a paywall, maybe someone would have access?

Is this the one?
https://sci-hub.tw/https://doi.org/10.1038/s41558-019-0557-y
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bluesky

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Re: Carbon Cycle
« Reply #510 on: September 07, 2019, 10:29:01 PM »
<snip>
Article in Nature Climate Change is under a paywall, maybe someone would have access?

Is this the one?
https://sci-hub.tw/https://doi.org/10.1038/s41558-019-0557-y

Yes it is! thank you, much appreciated

vox_mundi

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Re: Carbon Cycle
« Reply #511 on: October 01, 2019, 07:20:15 PM »
Humanity's Emissions '100-Times Greater' than Volcanoes
https://phys.org/news/2019-10-scientists-quantify-global-volcanic-co2.html
https://phys.org/news/2019-10-humanity-emissions-times-greater-volcanoes.html


Histograms of carbon influx (positive values) and outflux (negative values) to the atmosphere and the oceans. Units are in Pg C/y. (A) Carbon fluxes based on steady state models. Abbreviations: MOR = mid ocean ridge; org carbon = organic carbon. (B) Carbon fluxes as a result of large-scale perturbations to the carbon cycle. Total outgassing refers to events listed in Figure 2A; anthropogenic is human contributions; Chicxulub (Mexico) refers to the end-Cretaceous asteroid impact and resultant mass extinction; average LIP refers to the input from large igneous provinces.

The Deep Carbon Observatory (DCO), a 500-strong international team of scientists, released a series of papers outlining how carbon is stored, emitted and reabsorbed by natural and manmade processes.

They found that manmade carbon dioxide emissions drastically outstrip the contribution of volcanoes—which belch out gas and are often fingered as a major climate change contributor—to current warming rates.

The findings, published in the journal Elements, showed just two-tenths of 1 percent of Earth's total carbon—around 43,500 gigatonnes—is above the surface in oceans, the land, and in our atmosphere.

The rest—a staggering 1.85 billion gigatonnes—is stored in our planet's crust, mantle and core, providing scientists with clues as to how Earth formed billions of years ago.

... They found that in general the planet self-regulated atmospheric levels of carbon dioxide, a key greenhouse gas, over geological timeframes of hundreds of thousands of years.

The exceptions to this came in the form of "catastrophic disturbances" to Earth's carbon cycle, such as immense volcanic eruptions or the meteor strike that killed off the dinosaurs.

The team estimated that the Chicxulub impact 66 million years ago, which killed off three-quarters of all life on Earth, released between 425 and 1,400 gigatonnes of CO2.

Manmade emissions in 2018 alone topped 37 gigatonnes.

By comparison, the CO2 released annually by volcanoes hovers around 0.3 and 0.4 gigatonnes—roughly 100 times less than manmade emissions.

"The amount of CO2 pumped into the atmosphere by anthropogenic (manmade) activity in the last 10-12 years (is equvalent) to the catastrophic change during these events we've seen in Earth's past,"
Edmonds told AFP.

Celina Suarez, Associate Professor of Geology at the University of Arkansas, said modern manmade emissions were the "same magnitude" as past carbon shocks that precipitated mass extinction.

"We are on the same level of carbon catastrophe which is a bit sobering,"
she told AFP.

"Climate deniers always say that Earth always rebalances itself," said Suarez.

"Well, yes it has. It will rebalance itself, but not on a timescale that is of signficance to humans."
« Last Edit: October 01, 2019, 07:26:01 PM by vox_mundi »
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pikaia

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Re: Carbon Cycle
« Reply #512 on: October 25, 2019, 11:52:13 AM »
"In the turbid, frigid waters roaring from the glaciers of Canada’s high Arctic, researchers have made a surprising discovery: for decades, the northern rivers secretly pulled carbon dioxide from the atmosphere at a rate faster than the Amazon rainforest."

ttps://www.theguardian.com/environment/2019/oct/25/scientists-glacial-rivers-absorb-carbon-faster-rainforests

kassy

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Re: Carbon Cycle
« Reply #513 on: October 25, 2019, 01:17:31 PM »
Interesting.

The mechanism:
In temperate rivers, a bounty of organic material – plant life and fish – results in higher levels of decomposition, meaning the bodies of water emit a far greater amount of carbon dioxide into the atmosphere than they absorb.

But glacial rivers, with their milky appearance and silt-laden composition, are not very hospitable to aquatic life, leading to far less organic decay – and little carbon output.

At the same time, the fine sediment scraped from glaciers, including silicate and carbonate, when tossed along in the rushing waters, begins the geological process known as chemical weathering.

*
Faster is not more:

“On a per-metre-squared basis, these rivers can consume a phenomenal amount of carbon dioxide,” said St Pierre. But their limited size means on a gross scale, they pull in far less than the sprawling Amazon.
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JMP

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Re: Carbon Cycle
« Reply #514 on: October 29, 2019, 05:25:04 PM »
This seems like quite a break-through in understanding.

Study finds fungi, not plant matter, responsible for most carbon sequestration in northern forests
https://phys.org/news/2013-03-fungi-responsible-carbon-sequestration-northern.html?fbclid=IwAR3PcB6XPEY5lAmM2Pj_T829JD954qG61OWMfdyWLE_1K06tSzGkA09X0sk

Quote
Scientists have known for quite some time that northern forests sequester a lot of carbon—they pull in carbon dioxide after all, and "breath" out oxygen. But what the trees actually do with the carbon has been a matter of debate—most have suggested that it's likely carried to needles and leaves then eventually drops to the forest floor where over time decomposition causes it to leech into the soil. If that were the case, this new team of researchers reasoned, then the newest carbon deposits should appear closest to the surface of the forest floor. But this is not what they found—instead they discovered that newer deposits were more likely to be found at deeper levels in the soil. This was because, they learned, the trees were carrying much of the carbon they pulled in down to their roots (via sugars) where it was being sequestered by a type of fungi (ectomycorrhizal, aka mycorrhizal fungi) that eats the sugars and expels the residue into the soil.

In their study they found that 47 percent of soil carbon found on large island samples came about due to fungi, as did a whopping 70 percent of carbon in small island soil samples. Thus far, the team is only able to guess why there are such differences in the soils, but theorize it's likely due to differences in decomposition rates.

I wonder if the sequestering fungi associated with the tree roots are yet being directly fed by falling needles etc? Or, are they saying something else entirely?  Because I always assumed fungi to be involved in the breakdown of dead plant material - just never understood it to be transmitted so deeply in the soil....     

nanning

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Re: Carbon Cycle
« Reply #515 on: October 30, 2019, 04:22:42 AM »
Very interesting JMP.

I think you are thinking about different fungi.
There is the symbiosis of the tree roots with a network of fungi: https://en.wikipedia.org/wiki/Mycorrhiza

Breakdown of leaves, needles etc. is amongst other lifeforms done by different kinds of fungi if I understand correctly.
https://en.wikipedia.org/wiki/Forest_floor
https://link.springer.com/article/10.1007/s40974-017-0064-9 "Litter decomposition in forest ecosystems: a review"
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kassy

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Re: Carbon Cycle
« Reply #516 on: October 30, 2019, 02:04:55 PM »
Nice article JMP!

This is one more mechanism which helps big old trees sequester more carbon.
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vox_mundi

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Re: Carbon Cycle
« Reply #517 on: October 30, 2019, 09:31:16 PM »
Carbon Bomb: Study Says Climate Impact from Loss of Intact Tropical Forests Grossly Underreported
https://phys.org/news/2019-10-carbon-climate-impact-loss-intact.html

A new study in the journal Science Advances says that carbon impacts from the loss of intact tropical forests has been grossly underreported.

The study calculates new figures relating to intact tropical forest lost between 2000-2013 that show a staggering increase of 626 percent in the long-term net carbon impacts through 2050. The revised total equals two years' worth of all global land-use change emissions.

Researchers found that direct clearance of intact tropical forests resulted in just 3.2 percent of gross carbon emissions from all deforestation across the pan-tropics. However, when they factored in full carbon accounting, which considers forgone carbon removals (carbon sequestration that would occur annually into the future if cleared or degraded forest had remained intact after year 2000), selective logging, edge effects and declines of carbon-dense tree species due to overhunting of seed-dispersing animals, they discovered that the figure skyrocketed by a factor of more than six times.

... The authors go on to say that a comparable analysis is needed for intact forests outside of the tropics such as the boreal forests of Canada and Russia, given that approximately half to two-thirds of carbon removals on earth's intact ecosystems occur outside the tropics. Without this global clean-up service, CO2 from human activities would accumulate in the atmosphere markedly faster than it does at present.



Open Access: Sean L. Maxwell, et.al. "Degradation and forgone removals increase the carbon impact of intact forest loss by 626%" Science Advances (2019)
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jai mitchell

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Re: Carbon Cycle
« Reply #518 on: November 05, 2019, 08:08:11 PM »
the total carbon weight in the fungi below an old growth forest is approximately the same as the carbon weight (about 1/2 of total tree weight) of the forest above ground.

For more listen to this wonderful radiolab podcast on the subject.  https://www.wnycstudios.org/podcasts/radiolab/articles/from-tree-to-shining-tree

This seems like quite a break-through in understanding.

Study finds fungi, not plant matter, responsible for most carbon sequestration in northern forests
https://phys.org/news/2013-03-fungi-responsible-carbon-sequestration-northern.html?fbclid=IwAR3PcB6XPEY5lAmM2Pj_T829JD954qG61OWMfdyWLE_1K06tSzGkA09X0sk

Quote
Scientists have known for quite some time that northern forests sequester a lot of carbon—they pull in carbon dioxide after all, and "breath" out oxygen. But what the trees actually do with the carbon has been a matter of debate—most have suggested that it's likely carried to needles and leaves then eventually drops to the forest floor where over time decomposition causes it to leech into the soil. If that were the case, this new team of researchers reasoned, then the newest carbon deposits should appear closest to the surface of the forest floor. But this is not what they found—instead they discovered that newer deposits were more likely to be found at deeper levels in the soil. This was because, they learned, the trees were carrying much of the carbon they pulled in down to their roots (via sugars) where it was being sequestered by a type of fungi (ectomycorrhizal, aka mycorrhizal fungi) that eats the sugars and expels the residue into the soil.

In their study they found that 47 percent of soil carbon found on large island samples came about due to fungi, as did a whopping 70 percent of carbon in small island soil samples. Thus far, the team is only able to guess why there are such differences in the soils, but theorize it's likely due to differences in decomposition rates.

I wonder if the sequestering fungi associated with the tree roots are yet being directly fed by falling needles etc? Or, are they saying something else entirely?  Because I always assumed fungi to be involved in the breakdown of dead plant material - just never understood it to be transmitted so deeply in the soil....     
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vox_mundi

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Re: Carbon Cycle
« Reply #519 on: November 09, 2019, 06:40:57 PM »
Arctic Shifts To a Carbon Source Due to Winter Soil Emissions
https://eurekalert.org/pub_releases/2019-11/nsfc-ast110819.php

A NASA-funded study suggests winter carbon emissions in the Arctic may be adding more carbon into the atmosphere each year than is taken up by Arctic vegetation, marking a stark reversal for a region that has captured and stored carbon for tens of thousands of years.

The study, published Oct. 21 in Nature Climate Change, warns that winter carbon dioxide loss from the world's permafrost regions could increase by 41% over the next century if human-caused greenhouse gas emissions continue at their current pace. Carbon emitted from thawing permafrost has not been included in the majority of models used to predict future climates.

"These findings indicate that winter carbon dioxide loss may already be offsetting growing season carbon uptake, and these losses will increase as the climate continues to warm," said Woods Hole Research Center Arctic Program Director Sue Natali, lead author of the study. "Studies focused on individual sites have seen this transition, but until now we haven't had a clear accounting of the winter carbon balance throughout the entire Arctic region."

Researchers estimate a yearly loss of 1.7 billion metric tons of carbon from the permafrost region during the winter season from 2003 to 2017 compared to the estimated average of 1 billion metric tons of carbon taken up during the growing season. ... "The warmer it gets, the more carbon will be released into the atmosphere from the permafrost region, which will add to further warming," ... . If fossil fuel use is modestly reduced over the next century, winter carbon dioxide emissions would increase 17% compared with current emissions. Under a scenario where fossil fuel use continues to increase at current rates through the middle of the century, winter carbon dioxide emissions from permafrost would rise by 41%.
“There are three classes of people: those who see. Those who see when they are shown. Those who do not see.” ― Leonardo da Vinci

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kassy

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Re: Carbon Cycle
« Reply #520 on: November 09, 2019, 08:29:21 PM »
The idea of stopping global warming was mainly the idea to stop feedbacks such as those from happening. :(

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Pmt111500

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Re: Carbon Cycle
« Reply #521 on: November 10, 2019, 04:17:42 AM »
Quote
Carbon emitted from thawing permafrost has not been included in the majority of models used to predict future climates

No, of course it was not included. [Sarc] "what? Why should we? It'll mess up our weather model! We don't want messed up weather because of your poorly constrained carbon emissions! What are your error bars, when do we know if this section of code works properly if it changes the climate output too much?" [/Sarc]
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Hefaistos

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Re: Carbon Cycle
« Reply #522 on: November 10, 2019, 02:05:02 PM »
This seems like quite a break-through in understanding.

Study finds fungi, not plant matter, responsible for most carbon sequestration in northern forests
...
In their study they found that 47 percent of soil carbon found on large island samples came about due to fungi, as did a whopping 70 percent of carbon in small island soil samples. Thus far, the team is only able to guess why there are such differences in the soils, but theorize it's likely due to differences in decomposition rates.

Another very interesting and novel paper just out, with a global mapping of the location and extent of this essential symbiosis with fungi.
Paper in Nature relating ecosystem processes to the functioning of distinct types of mycorrhizas on a global scale. Open access.
"Global mycorrhizal plant distribution linked to terrestrial carbon stocks"
Because our maps are based on field data, and not on a machine-learning model trained with environmental variables, they provide independent data for examining the relationships between mycorrhizal status and ecosystem functioning, without introducing a circular reasoning caused by the use of common environmental variables. ... Our maps enable quantifying relationships between mycorrhizal abundances in ecosystems as well as soil and vegetation carbon content in global-scale analyses of biogeochemical cycles. In particular, the results of our study suggest that restoration of native vegetation especially in abandoned agricultural and barren land may help alleviate anthropogenic soil carbon losses and ameliorate increases in atmospheric greenhouse gases."

In related research, it has been recently reported that CO2 levels expected by the end of the century should increase plant biomass by 12%, enabling plants and trees to store more CO2 – an amount equivalent to six years of current fossil fuel emissions. The study highlights important partnerships trees forge with mycorrhizal fungi to help them take up the extra nitrogen and phosphorus they need to balance their additional CO2 intake.

https://www.iiasa.ac.at/web/home/about/news/190812-preserving-forests.html


https://www.nature.com/articles/s41467-019-13019-2

Figure byline: Percentage of aboveground plant biomass of mycorrhizal vegetation. a Arbuscular mycorrhizal plants, b ectomycorrhizal plants, c ericoid mycorrhizal plants, and d non-mycorrhizal plants. The map resolution is 10 arcmin.


NotaDenier

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Re: Carbon Cycle
« Reply #523 on: November 16, 2019, 12:29:58 PM »
https://science.sciencemag.org/content/354/6313/747.full?utm_campaign=postfity&utm_medium=social&utm_source=twitter



Regarding the future evolution of sea ice, our analysis suggests that there is little reason to believe that the observed sensitivity of Arctic sea-ice loss will change substantially in the forseeable future. Hence, we can directly estimate that the remainder of Arctic summer sea ice will be lost for roughly an additional 1000 Gt of CO2 emissions on the basis of the observed sensitivity of 3.0 ± 0.3 m2 September sea-ice loss per ton of anthropogenic CO2 emissions. Because this amount is based on the 30-year running mean of monthly averages, it is a very conservative estimate of the cumulative emissions at which the annual minimum sea-ice area drops below 1 million km2 for the first time. In addition, internal variability causes an uncertainty of around 20 years as to the first year of a near-complete loss of Arctic sea ice (18, 30). For current emissions of 35 Gt CO2 per year, the limit of 1000 Gt will be reached before mid-century. However, our results also imply that any measure taken to mitigate CO2 emissions will directly slow the ongoing loss of Arctic summer sea ice. In particular, for cumulative future total emissions compatible with reaching a 1.5°C global warming target—i.e., for cumulative future emissions appreciably below 1000 Gt—Arctic summer sea ice has a chance of long-term survival, at least in some parts of the Arctic Ocean.


mitch

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Re: Carbon Cycle
« Reply #524 on: November 16, 2019, 05:12:35 PM »
I haven't read the Notz and Stroeve paper in detail, but they apparently relate sea ice area to cumulative CO2 emissions. I find that puzzling because the effects of current emissions are offset by a couple of decades. 

I think the paper is overly optimistic.  Incidentally, total CO2 emissions since 1750 is about 600 Gt C

jai mitchell

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Re: Carbon Cycle
« Reply #525 on: November 19, 2019, 07:14:34 PM »
I read it when it came out, they looked at emissions and sea ice loss to find a very basic linear relationship.  They did not include the operation of aerosols on sea ice extent and so their linear relationship is very likely overly conservative.
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NotaDenier

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Re: Carbon Cycle
« Reply #526 on: November 30, 2019, 01:14:47 PM »

Bruce Steele

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Re: Carbon Cycle
« Reply #527 on: December 30, 2019, 05:43:18 PM »
A letter to a fisherman friend
Jon, There is a current called the Oyashio that flows south along the Eurasian continent from Russia towards Japan. As it mixes with very cold salty water that is the result of ice formation in the Sea of Okhotsk , the mixed water sinks to form intermediate waters that then flow across the Pacific under the Kuroshio Current. When the Oyashio sinks it carries
all the plankton and biogenic material to depths where it is dark . The plankton dies and is consumed by bacteria. This process is called remineralization , the biological material is changed back into it’s mineral components. Nitrogen, calcium, carbon ,phosphorus ,and potash are returned to the water and will eventually upwell and provide fertilizers for plankton and plants to grow again. When the carbon is released it oxidizes and CO2 is the result. The CO2 then turns into carbonic acid and a Hydrogen ion is released. Free Hydrogen ions are what are measured by a pH meter. The water becomes more acidic and  the bacterial remineralization process uses oxygen so the water also loses oxygen.
The intermediate water formed off Japan takes about 35-50 to cross the pacific and  it will upwell along the Pacific coast bringing up it’s load of dissolved CO2 . When we get strong upwelling conditions from spring through summer we also get upwelling and water acidified enough to dissolve shell material( calcium carbonate ). This process is called ocean acidification.
Half of the extra CO2 we release from burning fossil fuels is taken up by plant growth on land and in the oceans, the rest stays in the atmosphere. The part that is taken up by plankton sinks because of the calcium carbonate shells that some plankton make. This is good because it takes atmospheric CO2 , converts it to shells , and sinks the carbon into the deep ocean... for awhile , up to a thousand years. The problem is shell formation releases hydrogen ions and acidifies surface water. The worlds oceans have taken up about 30% more hydrogen ions than where there before we started to burn fossil fuels and as a result the ocean is about thirty percent more acidic than it was two hundred years ago.
At some point the surface waters become too acidic to support shell growth and the CO2 will stay in the surface waters , building up there instead of sinking. The process of ice formation and the cold brine that is squeezed out also happens around Antarctica and in the North Atlantic. Our earth is dependent upon ice formation to take cold water to depth along with the organic matter it contains. As the earth heats  this process slowly losses strength.  The earths atmosphere also increases in humidity as it heats resulting in more evaporation. This causes more rain which erodes minerals that will flow back into the oceans and slowly neutralize the extra hydrogen ions we put there by burning fossil fuels. Problem is the neutralization process takes thousands and thousands of years to rebalance ocean pH... up to a hundred thousand years .
We my friend are headed into an extinction event that will challenge the other five major extinction events over the last 500 million years. Ocean acidification and heating will be one of the main drivers along with ocean hypoxia and anaerobic oxygen conditions.
Trying to shorten acidification into a few short paragraphs obviously leaves out details ! The shells that sink onto the shelf are generally preserved and contribute to very long term carbon burial. Potentially millions of years. If the shell falls into intermediate or deep water in the Pacific it will dissolve and upwell within a thousand years. As the ocean acidifies the area of shelf exposed to undersaturated water increases and the area that supports long term calcium carbonate burial will shrink.

TerryM

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Re: Carbon Cycle
« Reply #528 on: December 30, 2019, 10:33:17 PM »
^^
Great overview!


We once had a proliferation of fresh water shells in my area, their all gone but for a small reef only easily accessible by canoe.
Two of the earliest manufacturers here specialized in buttons formed from the then abundant shells.


I've no idea what killed off the shells. Many of the rivers/streams were terribly polluted when I was young. They've done wonders cleaning them up, but the shells never returned.


Would these shells also have been secreting carbon? Would they act as long time storage?
Would reseeding these streams/rivers be a viable way to sequester CO2?


Thanks
Terry


Bruce Steele

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Re: Carbon Cycle
« Reply #529 on: December 31, 2019, 02:51:00 AM »
Terry, I remember freshwater clams in the Powder River NE Oregon. We would go collect crawdads and eat them, and you would run into clams as you shuffled around catching crawdads.
 I haven’t thought about them in a long time and a quick search on freshwater clams was kinda depressing. We don’t really deal with extinction in saltwater habitats but freshwater is a different story.
https://www.nrcs.usda.gov/Internet/FSE_DOCUMENTS/nrcs144p2_054084.pdf

 Freshwater clams form nacre and I believe nacre helps protect mollusk shells from low pH conditions. It does in saltwater conditions so likely in freshwater also. Both salt and freshwater clams , mussels or snails all make their shells from calcium carbonate. So yes the shells can hold carbon for a long time. It however they are exposed to low pH water or acidic soils they will dissolve and release their carbon stores.
 It is a good sign that you still have some clams in the river , they seem to not exist in S.Calif anymore.

TerryM

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Re: Carbon Cycle
« Reply #530 on: December 31, 2019, 07:23:35 AM »
It's a single protected reef that takes ~ 2 hours by canoe to visit, so more of a beach head than a revival.
There's a great agency that's in charge of the river and I know a person who may still be on the board. I'll try approaching him about reseeding the river with clams & I'll report his response.


On a one time island in the long dried up Silver Lake in the Mojave there is a gigantic clam midden that must be >10K yrs old (that's when the lake dried up). The shells are thin and fragile, but they still hold their form (until you attempt to remove one). ~50% of the carbon has lasted >10K years!
If reseeding freshwater clams is feasible, it might be an economical way to draw down some portion of the excess CO2.


Now that you mention it I haven't seen a single crawdad since I returned, and I was doing a fair amount of canoeing until the last few years. Are they still plentiful in California?
Terry

Bruce Steele

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Re: Carbon Cycle
« Reply #531 on: December 31, 2019, 08:49:54 PM »
If I ever get a chance I’d like to see those middens ! There is an island furthest west in the Channel Islands called San Miguel. There are middens there a hundred feet deep. There are freshwater springs on a desert island, several. Humans came to San Miguel in canoes about 15,000 years ago, the oldest dated human bones in California came from the islands. They didn’t have to contend with grizzlies, or big cats or wolves and lived off what the ocean provided. 
 I like the idea of trying to learn more about the clams that are now missing around here. Bringing back species that have gone missing is fighting upstream but what the hell , might as well swing for the fences. I suppose Sam is correct about our collective tendencies but somehow dedicated individuals can still fight this thing we call progress. And not write off what is missing, or give up on those on their way out. Even if Sam is right.
 

TerryM

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Re: Carbon Cycle
« Reply #532 on: December 31, 2019, 11:05:55 PM »
I think we as a species don't play well with others. With incentives in place we have however managed to clean up some of our waterways with amazing success.
It's been a while since any rivers have caught on fire, and my local stream now produces trout, even salmon. 60 years ago carp and suckers were all that could survive in the open sewer it had become.


Silver lake is N of I-15 at Baker, and the former island with the midden is close to the northern "shore" of the dried lakebed. The midden in in a gulch S, or SE of the highest rise. If you do chose to go look for the pre-Clovis fish traps still extant off the southern shore of the "island". They're "V" shaped, or shaped as a crescent with the points headed back toward the shore. The shells are 3-5 inches long & it's hard to miss the glint.
I've never found any worked stone, but that doesn't mean that none exists. it's possibly a 3/4 hour from the freeway & to the left of the dirt road you'll be following.
Today's GPS's probably make such detailed directions unneeded.


San Miguel's midden sounds wondrous. I've never been to any of the islands save for Santa Catalina.


Hope the pig plague has been kept at bay!
Terry

vox_mundi

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Re: Carbon Cycle
« Reply #533 on: January 13, 2020, 08:38:04 PM »
Simulations Show Parts of Amazon Switch from Carbon Sink to Carbon Source by 2050
https://m.phys.org/news/2020-01-simulations-amazon-carbon-source.html

A team of researchers led by Paulo Brando, assistant professor at the University of California, Irvine, has found evidence that parts of the Amazon Rainforest could switch from a carbon sink to a carbon source by 2050. In their paper published in the journal Science Advances, the group describes environmental simulations they developed and what they learned from them.

Their simulations showed that if deforestation continues at its current rate, the increased dryness that results would lead to burning approximately 16 percent of the southern Brazilian Amazon forest by 2050. That amount of lost forest, they suggest, could be enough to flip the region from a carbon sink to a carbon source. And that would mean an increase in greenhouse gases in the atmosphere, leading to a hotter planet.

Open Access:P.M. Brando at University of California, Irvine in Irvine, CA el al., "The gathering firestorm in southern Amazonia," Science Advances (2019)
“There are three classes of people: those who see. Those who see when they are shown. Those who do not see.” ― Leonardo da Vinci

Insensible before the wave so soon released by callous fate. Affected most, they understand the least, and understanding, when it comes, invariably arrives too late

Bruce Steele

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Re: Carbon Cycle
« Reply #534 on: January 13, 2020, 10:00:41 PM »
I don’t think my “letter to a fisherman friend” explains why we are in a different world than we were in when we started our diving careers . So I wrote an addendum to my letter post 1495 above.

The Oyashio current has a pCO2 that is about the same as atmospheric levels of CO2 .
A large annual spring diatom bloom pulls about half of its pCO2 out of the water, converts it to organic matter and shell that then sinks as it dies. When I first started diving in the early 1970’s the water upwelling along our coast came from Intermediate water formation processes with 305ppm atmospheric conditions.  The problems we are now seeing with surface undersaturation during spring upwelling season  can be traced back to Intermediate water formed when the atmospheric levels were ~ 340ppm. The biological and chemical processes that convert surface levels of dissolved CO2 into much higher levels of dissolved CO2 at intermediate depths have kept pace with increasing levels of atmospheric CO2 . The Intermediate water that will form this year will show up in upwelled water along the west coast of North America in about forty years. The difference between 305ppm back in the 1930s and current levels around 410ppm will result in undersaturated waters that will dominate our spring and summer seasons. We can expect pCO2 to be around 1200ppm equivalent when it arrives and upwells.
 There is a huge difference between 340ppm with the resulting undersaturation we currently see and what will result from 410ppm formation water conditions.


kassy

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Re: Carbon Cycle
« Reply #535 on: January 13, 2020, 10:21:25 PM »
Thanks for both Bruce. We often look at things on a very general level but often the message there gets to be rather abstract. In zooming in on these particulars it gets quite a bit clearer.

It´s a thing which some of the best science news writing does well but not quite enough.
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Juan C. García

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Re: Carbon Cycle
« Reply #536 on: January 16, 2020, 06:39:25 AM »
Quote
Mid-Pleistocene transition in glacial cycles explained by declining CO2 and regolith removal
M. Willeit,*, A. Ganopolski, R. Calov and V. Brovkin

Abstract
Variations in Earth’s orbit pace the glacial-interglacial cycles of the Quaternary, but the mechanisms that transform regional and seasonal variations in solar insolation into glacial-interglacial cycles are still elusive. Here, we present transient simulations of coevolution of climate, ice sheets, and carbon cycle over the past 3 million years. We show that a gradual lowering of atmospheric CO2 and regolith removal are essential to reproduce the evolution of climate variability over the Quaternary. The long-term CO2 decrease leads to the initiation of Northern Hemisphere glaciation and an increase in the amplitude of glacial-interglacial variations, while the combined effect of CO2 decline and regolith removal controls the timing of the transition from a 41,000- to 100,000-year world. Our results suggest that the current CO2 concentration is unprecedented over the past 3 million years and that global temperature never exceeded the preindustrial value by more than 2°C during the Quaternary.
https://advances.sciencemag.org/content/5/4/eaav7337
Which is the best answer to Sep-2012 ASI lost (compared to 1979-2000)?
50% [NSIDC Extent] or
73% [PIOMAS Volume]

Volume is harder to measure than extent, but 3-dimensional space is real, 2D's hide ~50% thickness gone.
-> IPCC/NSIDC trends [based on extent] underestimate the real speed of ASI lost.

sidd

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Re: Carbon Cycle
« Reply #537 on: January 16, 2020, 08:20:43 AM »
 I saw the Willeit paper last year and it is one of the first convincing explanations of the 40Kyr-100Kyr transition in glaciation period. Worth reading.

sidd

Bruce Steele

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Re: Carbon Cycle
« Reply #538 on: January 25, 2020, 05:45:04 PM »
I am involved in the politics of climate change because of a forty year career as a commercial fisherman. Last night I attended an award ceremony for the marine reserve network established around the Calif.Channel Islands about twenty years ago. I was sitting as the fisheries representative on the Channel Islands National Marine Sanctuary Committee while the reserves were designed and implemented . I also gained some respect as a “Cassandra” because I became aware of ocean acidification fifteen years ago and via my seat on the Sanctuary I communicated my concerns . People remember . I am still involved in fisheries politics and last week drove into LA for a two day scenario planning workshop on climate change and it’s potential effects on Calif. current fisheries put on by the PFMC, Pacific Fisheries Management Council.  Acidification is a mystery no more and fisheries scientists are just as concerned as I am . We have the long term after affects of “ the blob “ we are dealing with and the future of our anadromous fish stocks looks truly dire.
 We have NOAA cruises that have been documenting the chemical and biological consequences of acidification and the annual shoaling of the aragonite horizon onto the continental shelf is well documented. We are now also seeing the calcite horizon beginning to shoal onto the shelf. Pteropod shell dissolution has been documented during these upwelling events and now Dungeness crab larva are also showing signs of shell dissolution in their native habitats.
    https://research.noaa.gov/article/ArtMID/587/ArticleID/2581/Dungeness-crab-showing-impact-of-coastal-acidification
   ( notice the graph in the article is for calcite not aragonite. )
 The intermediate water formation processes responsible for the acidification responsible were driven by atmospheric CO2 conditions that were about 100ppm less than current conditions. The acidification resulting from current North Pacific Intermediate Water processes will arrive in upwelled water in forty years here in the Calif. Current.  We will be seeing the calcite horizon shoaled to the surface by then.  Every scientist with a clue knows the consequences will be catastrophic ! So I have been suggesting we as fisheries managers start the conversation about how to repower the fishing fleet. Food production methods whether fishing or farming can’t continue to  ignore the CO2 contribution we are collectively responsible for. I am banging the drum , I am not shy, and Cassandra has a history.
 Driving through LA is always a gut check for me , the system is way past overshoot and IMO we are just as doomed as the pteropods and the crabs . LOTs of very bright people have the same opinion but somehow getting on the plane or ignoring the fossil fuel dependence of our food production doesn’t trigger the cognitive dissonance in them that it does in me.
 
 
« Last Edit: January 25, 2020, 05:54:19 PM by Bruce Steele »

kassy

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Re: Carbon Cycle
« Reply #539 on: January 25, 2020, 08:46:45 PM »
So this is the result of 300 - 310 ppm?
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Bruce Steele

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Re: Carbon Cycle
« Reply #540 on: January 25, 2020, 09:19:15 PM »
Current conditions of west coast upwelling are from Intermediate water formation processes about forty years ago .
So 1980 levels were ~337ppm. Those levels of atmospheric CO2 have resulted in the calcite horizon beginning to shoal onto the shelf. ( personal communication with one of the authors on the paper linked above )
 310ppm was where the atmospheric levels were that were responsible for water that upwelled when I started my fishing career. Waters that were high in pCO2 and of low pH and an aragonite omega below 1.6 started affecting oyster aquaculture in 2006. It wasn’t an issue before that time. Formation waters were from 1965 at around 320ppm
 So aragonite horizon shoals onto shelf at 320ppm. Pacific oysters impacted
      Calcite horizon shoals onto shelf at 337ppm.     Dungeness and pteropods impacts
Formation waters from atmospheric 410ppm are already on their way
Does not end well .

kassy

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Re: Carbon Cycle
« Reply #541 on: January 25, 2020, 10:00:55 PM »
As a hardcore landlubber the ocean acidification was always sort of abstract, some papers reported stuff doing badly. Future not too good. But it is not like i know oceans.

The way you wrote about it in that letter to a friend made stuff a lot clearer.

Repower or plan for a finite number of generations fishing?
Þetta minnismerki er til vitnis um að við vitum hvað er að gerast og hvað þarf að gera. Aðeins þú veist hvort við gerðum eitthvað.

mitch

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Re: Carbon Cycle
« Reply #542 on: January 25, 2020, 10:30:45 PM »
During upwelling season along the west coast of the US, pCO2 in the water responds very strongly to the recycling of nutrients--particulate matter from the water moving offshore at the surface falls into the incoming water and degrades there.  This drives pCO2 to very high levels, sometimes > 1000 ppm

https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2010JC006625