The closest analog to modern times is no longer very close, study finds.
A new study of an ancient period that is considered the closest natural analog to the era of modern human carbon emissions has found that massive volcanism sent great waves of carbon into the oceans over thousands of years — but that nature did not come close to matching what humans are doing today. The study estimates that humans are now introducing the element three to eight times faster, or possibly even more. The consequences for life both in the water and on land are potentially catastrophic. The findings appear this week in the journal Proceedings of the National Academy of Sciences.
Researchers at Columbia University’s Lamont-Doherty Earth Observatory examined ocean conditions 55.6 million years ago, a time known as the Paleocene-Eocene Thermal Maximum (PETM). Before this, the planet was already considerably warmer than it is today, and the soaring CO2 levels of the PETM drove temperatures up another 5 to 8 degrees C (9 to 14 degrees F). The oceans absorbed large amounts of carbon, spurring chemical reactions that caused waters to become highly acidic, and killing or impairing many marine species.
Scientists have known about the PETM carbon surge for years, but until now, have been shaky on what caused it. Aside from volcanism, hypotheses have included the sudden dissolution of frozen methane (which contains carbon) from ocean-floor muds, or even a collision with a comet. Researchers have also been uncertain about how much carbon dioxide was present in the air, and thus how much the oceans took in. The new study solidifies both the volcano theory, and the amount of carbon that was released into the air.
The research is directly relevant to today, said lead author Laura Haynes, who did the research as a graduate student at Lamont-Doherty. “We want to understand how the earth system is going to respond to rapid CO2 emissions now,” she said. “The PETM is not the perfect analog, but it’s the closest thing we have. Today, things are moving much faster.” Haynes is now an assistant professor at Vassar College.
Up to now, marine studies of the PETM have relied on scant chemical data from the oceans, and assumptions based on a certain degree of guesswork that researchers fed into computer models.
The authors of the new study got at the questions more directly. They did this by culturing tiny shelled marine organisms called foraminifera in seawater that they formulated to resemble the highly acidic conditions of the PETM. They recorded how the organisms took up the element boron into their shells during growth. They then compared these data with analyses of boron from fossilized foraminifera in Pacific and Atlantic ocean-floor cores that span the PETM. This allowed them to identify carbon-isotope signatures associated with specific carbon sources. This indicated that volcanoes were the main source — probably from massive eruptions centered around what is now Iceland, as the North Atlantic ocean opened up, and northern North America and Greenland separated from northern Europe.
The researchers say the carbon pulses, which others estimate lasted for at least 4,000 to 5,000 years, added as much as 14.9 quadrillion metric tons of carbon to the oceans — a two-thirds increase over their previous content. The carbon would have come from CO2 emitted directly by the eruptions, the combustion of surrounding sedimentary rocks, and some methane welling up from the depths. As the oceans absorbed carbon from the air, waters became highly acidic, and remained that way for tens of thousands of years. There is evidence that this killed off much deep-sea life, and probably other marine creatures as well.
Today, human emissions are causing carbon dioxide in the atmosphere to skyrocket, and the oceans are again absorbing much of it. The difference is that we are introducing it much faster than the volcanoes did — within decades instead of millennia. Atmospheric levels have shot up from about 280 parts per million in the 1700s to about 415 today, and they are on a path to keep rising rapidly. Atmospheric levels would already be much higher if the oceans were not absorbing so much. As they do, rapid acidification is starting to stress marine life.
“If you add carbon slowly, living things can adapt. If you do it very fast, that’s a really big problem,” said the study’s coauthor Bärbel Hönisch, a geochemist at Lamont-Doherty. She pointed out that even at the much slower pace of the PETM, marine life saw major die-offs. “The past saw some really dire consequences, and that does not bode well for the future,” she said. “We’re outpacing the past, and the consequences are probably going to be very serious.”
Reference: “The seawater carbon inventory at the Paleocene–Eocene Thermal Maximum” by Laura L. Haynes and Bärbel Hönisch, 14 September 2020, Proceedings of the National Academy of Sciences.
The article states, “As the oceans absorbed carbon from the air, waters became highly acidic, and remained that way for tens of thousands of years.”
For starters, just what does “highly acidic” correspond to with respect to the hydrogen ion concentration, known as the pH? The oceans are, and have been, highly buffered, for hundreds of millions of years, with both carbonate and borate buffers. In the vicinity of Black Smokers and CO2 springs, the ocean waters become slightly acidic. However, even in the deep, cold waters, supercharged with CO2 from anaerobic decomposition of the organic plankton rain settling to the bottom, one does not see acidic water. Carbonic acid is a weak acid, meaning that it only partially ionizes in a water solution. To drive the oceans to a true acid state would require strong acids such as sulfurous or sulfuric acid, which can be derived from volcanic emissions. However, that doesn’t fit the story about the role of anthropogenic CO2 making the oceans “highly acidic” at a faster rate than during the PETM.
It is suggested that the rate of carbonization is at least, if not more so, as important as the total carbonation level. The facts supporting the supposition are not in evidence. The organisms most susceptible, potentially, to damage from a lowered pH are what are known as calcifiers. They are capable of altering the pH at the shell growth-interface by the expenditure of energy. They then protect the calcite/aragonite by covering it with mucous and chitin. Thus, they are able to survive in a wider range of lowered pH than is suggested by the dissolution of the shells from dead animals. The article, again, critically, doesn’t quantify what the pH conditions were claimed to have been. Only the highly ambiguous term “highly acidic” is provided.
Other than coal, what kind of sedimentary rocks can “combust?” If if was coal, why not say so?
This summary article can be no better than the original research. However, it strikes me that the original research was an attempt to find evidence to support a preconceived hypothesis, rather than being the work of a ‘disinterested observer’ looking for truth.
It sounds as though you might be aware of the answers you feel the journalist failed to make clear in the article.
“Highly acidic” would be 7.4 ph as you probably know.
The comparison between human produced CO2 and the earths creatiion of CO2 in the article are relevant because humans also use sulfuric acid and sulfurous heavily in industry including mining, drilling and fracking for oil and fertilizer for growing food.
All of which run into the ocean.
You know not of what you speak! By definition, 7.4 is alkaline. Acidic would be less than 7.0, like rainwater with a typical pH of about 5.6. I would personally consider something like acid mine drainage, with a negative pH to be “highly acidic.” Whether a solution is acidic or alkaline actually depends on the ratio of hydroxyl ions to hydronium ions. If the ratio is 1, then the solution is neutral, and it has a pH of 7.0. If the ratio is less than 1, then the solution is acidic.
Your last paragraph is really a non sequitur attempting to rationalize your misunderstandings about chemistry.
Take a look at this graphic and tell me again what you think a pH of 7.4 should be called:
What was the atmospheric ppm during the PTEM? This feels purposely left out… or is still an unknown. It says we are out pacing it, going up roughly 215ppm over 300 years, but it never says what the plan. Growth was during the eocene?
Ppm growth was*
Problem with answering on your phone, who thinks it knows better than you what you are trying to say.
I’m aware of the ph scale
Thought the author was inferring that during that period it was becoming “highly acidic” or moving toward <7 from an ideal 7.8. At 7.4 marine life was devastated during the period of that volcanism.
I believe the oceans current drop in ph is .1 which is about is alarming.
The author was inferring nothing. She explicitly said, “The oceans absorbed large amounts of carbon, spurring chemical reactions that CAUSED waters to become highly acidic, …” and that the condition persisted for “… tens of thousands of years.”
You say that you are “aware” of the “ph”[sic] scale, yet you claim that a speculated drop from 8.2 to 8.1 (“.1”) is alarming, and at the same time claim that 7.8 is “ideal.” The “ideal” pH is species specific and probably reflects the pH of the environment in which the species evolved. Calcifiers are able to tolerate a range of pH much greater than 0.1 units from their optimal pH by expending additional energy. This is particularly true of benthic organisms that live in upwelling zones where the pH can vary significantly over periods of minutes.
Being “aware” is an admission that you do not understand pH at the level you would like to have others believe. Your statements demonstrate that you actually have little experience with pH or the ocean environment.
One consequence of acidification is a nearly one-for-one reduction in the concentration of carbonate ions for every molecule of CO2 that dissolves in the ocean. The concentration of atmospheric CO2 is predicted to double by the end of this century; thus, the concentration of carbonate ions at the surface of the ocean will nearly halve by the year 2100. While the negative influence of acidification on corals and shellfish is known, there is a mechanism that affects life which forms the base of most marine food webs.
In large areas of the ocean, the scarcity of iron controls the growth and productivity of phytoplankton. Although most dissolved iron in the marine environment is complexed with organic molecules, picomolar amounts of labile inorganic iron species (labile iron) are maintained within the euphotic zone and serve as an important source of iron for eukaryotic phytoplankton and particularly for diatoms. Genome-enabled studies of labile iron utilization by diatoms have previously revealed novel iron-responsive transcripts including the ferric iron-concentrating protein ISIP2A but the mechanism behind the acquisition of picomolar labile iron remains unknown. Here we show that ISIP2A is a phytotransferrin that independently and convergently evolved carbonate ion-coordinated ferric iron binding. Deletion of ISIP2A disrupts high-affinity iron uptake in the diatom Phaeodactylum tricornutum, and uptake is restored by complementation with human transferrin. ISIP2A is internalized by endocytosis, and manipulation of the seawater carbonic acid system reveals a second-order dependence on the concentrations of labile iron and carbonate ions. In P. tricornutum, the synergistic interaction of labile iron and carbonate ions occurs at environmentally relevant concentrations, revealing that carbonate availability co-limits iron uptake. Phytotransferrin sequences have a broad taxonomic distribution and are abundant in marine environmental genomic data suggests that acidification-driven declines in the concentration of seawater carbonate ions will have a negative effect on this globally important eukaryotic iron acquisition mechanism
Your reply is obviously something that you copied without attribution. Do you even understand it?
I had previously challenged you to “Take a look at this graphic and tell me again what you think a pH of 7.4 should be called:” You ignored the question. I’ll answer it for you. Adjacent to pH 7.4 is the example, “Blood.” You expect people to believe that what we and other animals have coursing through our veins is “highly acidic?”
If you would actually like to learn something, instead of just cutting and pasting things that are beyond your level of understanding, try reading something else that I have written:
Do you and your silly little phishing scheme work?
Yes, of course I understand what I wrote. Do you understand the narrow band of focus that you contribute to the understanding of the research conducted above?
Obviously, you have a great knowledge of the building blocks of nature but yet don’t quite fit in. A multi-disciplinary approach or rather broader insight from you would probably be most valuable. But you prefer to disprove and refer to smokers out in the middle of the ocean which somehow are just like 5 miles off a shoreline.
Regardless for your thirst for academic confrontation humans are destroying the ocean, along with many other ecosystems and other natural habitats for other animals.
Put your mind to good use and find the correlations between our behavior, (Sapiens) and the destruction of many tiers of the earths existing natural flows.
We have and will continue to be the most influential source of destruction of this planet.
Why all the creepy links to read and hostility? Find the meaning fella and perhaps you can be part of the solution…
You are claiming to have written the comment at 5:59 am, despite it looking nothing like your previous style and vocabulary? How about explaining the sentence about half way down that starts with “Here we show that ISIP2A …”
Are you in the habit of using the ‘Royal We’ when talking about yourself? You are a fraud that doesn’t understand the subject that you are supporting. That probably explains why you support it. It is easy to deceive those who don’t understand what they are being told.
I’m pointing out the poor quality of the research and the apparent proselytizing, and questioning the conclusions of the research that you unquestioningly accept. One of the greatest threats to ecosystems is people who think they understand the problems, but don’t, and offer ‘solutions’ that aren’t appropriate. “The road to Hell is paved with good intentions.”
Off topic Clyde the academic confrontionalist.
What I have stated are facts and lend to the fact that your intentional narrow focus of the complex symbiotic web in the food chain is far more than you can comprehend. Apparently.