New perspectives for using corals in climate research

Research team led by Göttingen University expands the applications of oxygen isotope measurements

Peer-Reviewed Publication

University of Göttingen

 

image: 

Göttingen University researchers analysed oxygen isotopes from corals, like this Acropora coral, to expand the uses of the “triple oxygen isotope” method and help measure temperatures from the past more accurately. This is important for understanding the development of the climate.

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Credit: Dr David Bajnai

Measuring temperatures from Earth’s past is important for understanding the development of its climate. Ancient ocean temperatures are most commonly reconstructed by analysing the ratio of different oxygen atoms in the calcium carbonate remains of fossils. However, this presents many challenges, including a combination of biological processes known as “vital effects” which are very noticeable in corals and can affect the data. A research team led by the University of Göttingen now shows how the abundance of a third, very rare oxygen isotope can uncover whether the isotopic composition was solely influenced by temperature or if biological effects also played a role. The results were published in Geochemical Perspective Letters.

 

The hard structure of coral, known as the “coral skeleton”, is composed of calcium carbonate, the same material that makes up limestones. Corals, like all marine organisms, selectively incorporate different forms of oxygen. These different forms are called isotopes, meaning some oxygen atoms are lighter and some are heavier. At lower water temperatures, a higher abundance of the heavy oxygen isotope is incorporated into the carbonate structures. By analyzing the ratios of the heavy oxygen-18 isotope to the light oxygen-16 isotope in carbonates, scientists can calculate the ambient seawater temperatures of Earth's distant past. However, some carbonates, such as coral skeletons, return false temperatures because their oxygen isotope composition is also affected by the biological processes known as vital effects. The researchers have now discovered that a third, very rare isotope (oxygen-17) can be used to correct for these biological effects. As a result, researchers can now determine past ocean temperatures with greater accuracy, in addition to gaining more insights into the biomineralization processes of different coral species. Measurements of this rare oxygen-17 isotope, known in the field as the triple oxygen isotope method, in carbonates are normally very complicated. In fact, the stable isotope laboratory at the Göttingen University is among only a few in the world that can perform such analyses. The lab used cutting-edge instrumentation known as tuneable diode laser absorption spectroscopy.

 

“We used corals for our study as we know quite a lot about the processes by which they grow their skeletons,” said study leader, Dr David Bajnai at Göttingen University’s Geoscience Centre. “We are excited to apply this concept to other organisms commonly used in the study of Earth's past climate. We hope that triple oxygen isotope analyses will open up previously unusable datasets for paleoclimate research, enabling more accurate climate reconstructions, going further back in time.”

 

Professor Daniel Herwartz from the Ruhr University Bochum added, “We were also able to show that triple oxygen isotope analyses can inform us about the various processes we collectively call ‘vital effects’. For corals, we can now confirm that the main process involved is related to a chemical process called CO2 absorption, which we have independently studied in experiments. Such advanced techniques help to gain new insights into how organisms build their harder structures.”

 

Original publication: Bajnai, D. et al. “Correcting for vital effects in coral carbonate using triple oxygen isotopes”. Geochemical Perspectives Letters 2024. DOI: 10.7185/geochemlet.2430

 

Measuring temperatures from Earth’s past is important for understanding the development of its climate. Ancient ocean temperatures are most commonly reconstructed by analysing the ratio of different oxygen atoms in the calcium carbonate remains of fossils. However, this presents many challenges, including a combination of biological processes known as “vital effects” which are very noticeable in corals and can affect the data. A research team led by the University of Göttingen now shows how the abundance of a third, very rare oxygen isotope can uncover whether the isotopic composition was solely influenced by temperature or if biological effects also played a role. The results were published in Geochemical Perspective Letters.

 

The hard structure of coral, known as the “coral skeleton”, is composed of calcium carbonate, the same material that makes up limestones. Corals, like all marine organisms, selectively incorporate different forms of oxygen. These different forms are called isotopes, meaning some oxygen atoms are lighter and some are heavier. At lower water temperatures, a higher abundance of the heavy oxygen isotope is incorporated into the carbonate structures. By analyzing the ratios of the heavy oxygen-18 isotope to the light oxygen-16 isotope in carbonates, scientists can calculate the ambient seawater temperatures of Earth's distant past. However, some carbonates, such as coral skeletons, return false temperatures because their oxygen isotope composition is also affected by the biological processes known as vital effects. The researchers have now discovered that a third, very rare isotope (oxygen-17) can be used to correct for these biological effects. As a result, researchers can now determine past ocean temperatures with greater accuracy, in addition to gaining more insights into the biomineralization processes of different coral species. Measurements of this rare oxygen-17 isotope, known in the field as the triple oxygen isotope method, in carbonates are normally very complicated. In fact, the stable isotope laboratory at the Göttingen University is among only a few in the world that can perform such analyses. The lab used cutting-edge instrumentation known as tuneable diode laser absorption spectroscopy.

 

“We used corals for our study as we know quite a lot about the processes by which they grow their skeletons,” said study leader, Dr David Bajnai at Göttingen University’s Geoscience Centre. “We are excited to apply this concept to other organisms commonly used in the study of Earth's past climate. We hope that triple oxygen isotope analyses will open up previously unusable datasets for paleoclimate research, enabling more accurate climate reconstructions, going further back in time.”

 

Professor Daniel Herwartz from the Ruhr University Bochum added, “We were also able to show that triple oxygen isotope analyses can inform us about the various processes we collectively call ‘vital effects’. For corals, we can now confirm that the main process involved is related to a chemical process called CO2 absorption, which we have independently studied in experiments. Such advanced techniques help to gain new insights into how organisms build their harder structures.”

 

Original publication: Bajnai, D. et al. “Correcting for vital effects in coral carbonate using triple oxygen isotopes”. Geochemical Perspectives Letters 2024. DOI: 10.7185/geochemlet.2430

 

Measuring temperatures from Earth’s past is important for understanding the development of its climate. Ancient ocean temperatures are most commonly reconstructed by analysing the ratio of different oxygen atoms in the calcium carbonate remains of fossils. However, this presents many challenges, including a combination of biological processes known as “vital effects” which are very noticeable in corals and can affect the data. A research team led by the University of Göttingen now shows how the abundance of a third, very rare oxygen isotope can uncover whether the isotopic composition was solely influenced by temperature or if biological effects also played a role. The results were published in Geochemical Perspective Letters.

 

The hard structure of coral, known as the “coral skeleton”, is composed of calcium carbonate, the same material that makes up limestones. Corals, like all marine organisms, selectively incorporate different forms of oxygen. These different forms are called isotopes, meaning some oxygen atoms are lighter and some are heavier. At lower water temperatures, a higher abundance of the heavy oxygen isotope is incorporated into the carbonate structures. By analyzing the ratios of the heavy oxygen-18 isotope to the light oxygen-16 isotope in carbonates, scientists can calculate the ambient seawater temperatures of Earth's distant past. However, some carbonates, such as coral skeletons, return false temperatures because their oxygen isotope composition is also affected by the biological processes known as vital effects. The researchers have now discovered that a third, very rare isotope (oxygen-17) can be used to correct for these biological effects. As a result, researchers can now determine past ocean temperatures with greater accuracy, in addition to gaining more insights into the biomineralization processes of different coral species. Measurements of this rare oxygen-17 isotope, known in the field as the triple oxygen isotope method, in carbonates are normally very complicated. In fact, the stable isotope laboratory at the Göttingen University is among only a few in the world that can perform such analyses. The lab used cutting-edge instrumentation known as tuneable diode laser absorption spectroscopy.

 

“We used corals for our study as we know quite a lot about the processes by which they grow their skeletons,” said study leader, Dr David Bajnai at Göttingen University’s Geoscience Centre. “We are excited to apply this concept to other organisms commonly used in the study of Earth's past climate. We hope that triple oxygen isotope analyses will open up previously unusable datasets for paleoclimate research, enabling more accurate climate reconstructions, going further back in time.”

 

Professor Daniel Herwartz from the Ruhr University Bochum added, “We were also able to show that triple oxygen isotope analyses can inform us about the various processes we collectively call ‘vital effects’. For corals, we can now confirm that the main process involved is related to a chemical process called CO2 absorption, which we have independently studied in experiments. Such advanced techniques help to gain new insights into how organisms build their harder structures.”

 

Original publication: Bajnai, D. et al. “Correcting for vital effects in coral carbonate using triple oxygen isotopes”. Geochemical Perspectives Letters 2024. DOI: 10.7185/geochemlet.2430

 

Measuring temperatures from Earth’s past is important for understanding the development of its climate. Ancient ocean temperatures are most commonly reconstructed by analysing the ratio of different oxygen atoms in the calcium carbonate remains of fossils. However, this presents many challenges, including a combination of biological processes known as “vital effects” which are very noticeable in corals and can affect the data. A research team led by the University of Göttingen now shows how the abundance of a third, very rare oxygen isotope can uncover whether the isotopic composition was solely influenced by temperature or if biological effects also played a role. The results were published in Geochemical Perspective Letters.

 

The hard structure of coral, known as the “coral skeleton”, is composed of calcium carbonate, the same material that makes up limestones. Corals, like all marine organisms, selectively incorporate different forms of oxygen. These different forms are called isotopes, meaning some oxygen atoms are lighter and some are heavier. At lower water temperatures, a higher abundance of the heavy oxygen isotope is incorporated into the carbonate structures. By analyzing the ratios of the heavy oxygen-18 isotope to the light oxygen-16 isotope in carbonates, scientists can calculate the ambient seawater temperatures of Earth's distant past. However, some carbonates, such as coral skeletons, return false temperatures because their oxygen isotope composition is also affected by the biological processes known as vital effects. The researchers have now discovered that a third, very rare isotope (oxygen-17) can be used to correct for these biological effects. As a result, researchers can now determine past ocean temperatures with greater accuracy, in addition to gaining more insights into the biomineralization processes of different coral species. Measurements of this rare oxygen-17 isotope, known in the field as the triple oxygen isotope method, in carbonates are normally very complicated. In fact, the stable isotope laboratory at the Göttingen University is among only a few in the world that can perform such analyses. The lab used cutting-edge instrumentation known as tuneable diode laser absorption spectroscopy.

 

“We used corals for our study as we know quite a lot about the processes by which they grow their skeletons,” said study leader, Dr David Bajnai at Göttingen University’s Geoscience Centre. “We are excited to apply this concept to other organisms commonly used in the study of Earth's past climate. We hope that triple oxygen isotope analyses will open up previously unusable datasets for paleoclimate research, enabling more accurate climate reconstructions, going further back in time.”

 

Professor Daniel Herwartz from the Ruhr University Bochum added, “We were also able to show that triple oxygen isotope analyses can inform us about the various processes we collectively call ‘vital effects’. For corals, we can now confirm that the main process involved is related to a chemical process called CO2 absorption, which we have independently studied in experiments. Such advanced techniques help to gain new insights into how organisms build their harder structures.”

 

Original publication: Bajnai, D. et al. “Correcting for vital effects in coral carbonate using triple oxygen isotopes”. Geochemical Perspectives Letters 2024. DOI: 10.7185/geochemlet.2430

 

Measuring temperatures from Earth’s past is important for understanding the development of its climate. Ancient ocean temperatures are most commonly reconstructed by analysing the ratio of different oxygen atoms in the calcium carbonate remains of fossils. However, this presents many challenges, including a combination of biological processes known as “vital effects” which are very noticeable in corals and can affect the data. A research team led by the University of Göttingen now shows how the abundance of a third, very rare oxygen isotope can uncover whether the isotopic composition was solely influenced by temperature or if biological effects also played a role. The results were published in Geochemical Perspective Letters.

 

The hard structure of coral, known as the “coral skeleton”, is composed of calcium carbonate, the same material that makes up limestones. Corals, like all marine organisms, selectively incorporate different forms of oxygen. These different forms are called isotopes, meaning some oxygen atoms are lighter and some are heavier. At lower water temperatures, a higher abundance of the heavy oxygen isotope is incorporated into the carbonate structures. By analyzing the ratios of the heavy oxygen-18 isotope to the light oxygen-16 isotope in carbonates, scientists can calculate the ambient seawater temperatures of Earth's distant past. However, some carbonates, such as coral skeletons, return false temperatures because their oxygen isotope composition is also affected by the biological processes known as vital effects. The researchers have now discovered that a third, very rare isotope (oxygen-17) can be used to correct for these biological effects. As a result, researchers can now determine past ocean temperatures with greater accuracy, in addition to gaining more insights into the biomineralization processes of different coral species. Measurements of this rare oxygen-17 isotope, known in the field as the triple oxygen isotope method, in carbonates are normally very complicated. In fact, the stable isotope laboratory at the Göttingen University is among only a few in the world that can perform such analyses. The lab used cutting-edge instrumentation known as tuneable diode laser absorption spectroscopy.

 

“We used corals for our study as we know quite a lot about the processes by which they grow their skeletons,” said study leader, Dr David Bajnai at Göttingen University’s Geoscience Centre. “We are excited to apply this concept to other organisms commonly used in the study of Earth's past climate. We hope that triple oxygen isotope analyses will open up previously unusable datasets for paleoclimate research, enabling more accurate climate reconstructions, going further back in time.”

 

Professor Daniel Herwartz from the Ruhr University Bochum added, “We were also able to show that triple oxygen isotope analyses can inform us about the various processes we collectively call ‘vital effects’. For corals, we can now confirm that the main process involved is related to a chemical process called CO2 absorption, which we have independently studied in experiments. Such advanced techniques help to gain new insights into how organisms build their harder structures.”

 

Original publication: Bajnai, D. et al. “Correcting for vital effects in coral carbonate using triple oxygen isotopes”. Geochemical Perspectives Letters 2024. DOI: 10.7185/geochemlet.2430

 

Measuring temperatures from Earth’s past is important for understanding the development of its climate. Ancient ocean temperatures are most commonly reconstructed by analysing the ratio of different oxygen atoms in the calcium carbonate remains of fossils. However, this presents many challenges, including a combination of biological processes known as “vital effects” which are very noticeable in corals and can affect the data. A research team led by the University of Göttingen now shows how the abundance of a third, very rare oxygen isotope can uncover whether the isotopic composition was solely influenced by temperature or if biological effects also played a role. The results were published in Geochemical Perspective Letters.

 

The hard structure of coral, known as the “coral skeleton”, is composed of calcium carbonate, the same material that makes up limestones. Corals, like all marine organisms, selectively incorporate different forms of oxygen. These different forms are called isotopes, meaning some oxygen atoms are lighter and some are heavier. At lower water temperatures, a higher abundance of the heavy oxygen isotope is incorporated into the carbonate structures. By analyzing the ratios of the heavy oxygen-18 isotope to the light oxygen-16 isotope in carbonates, scientists can calculate the ambient seawater temperatures of Earth's distant past. However, some carbonates, such as coral skeletons, return false temperatures because their oxygen isotope composition is also affected by the biological processes known as vital effects. The researchers have now discovered that a third, very rare isotope (oxygen-17) can be used to correct for these biological effects. As a result, researchers can now determine past ocean temperatures with greater accuracy, in addition to gaining more insights into the biomineralization processes of different coral species. Measurements of this rare oxygen-17 isotope, known in the field as the triple oxygen isotope method, in carbonates are normally very complicated. In fact, the stable isotope laboratory at the Göttingen University is among only a few in the world that can perform such analyses. The lab used cutting-edge instrumentation known as tuneable diode laser absorption spectroscopy.

 

“We used corals for our study as we know quite a lot about the processes by which they grow their skeletons,” said study leader, Dr David Bajnai at Göttingen University’s Geoscience Centre. “We are excited to apply this concept to other organisms commonly used in the study of Earth's past climate. We hope that triple oxygen isotope analyses will open up previously unusable datasets for paleoclimate research, enabling more accurate climate reconstructions, going further back in time.”

 

Professor Daniel Herwartz from the Ruhr University Bochum added, “We were also able to show that triple oxygen isotope analyses can inform us about the various processes we collectively call ‘vital effects’. For corals, we can now confirm that the main process involved is related to a chemical process called CO2 absorption, which we have independently studied in experiments. Such advanced techniques help to gain new insights into how organisms build their harder structures.”

 

Original publication: Bajnai, D. et al. “Correcting for vital effects in coral carbonate using triple oxygen isotopes”. Geochemical Perspectives Letters 2024. DOI: 10.7185/geochemlet.2430

 

Measuring temperatures from Earth’s past is important for understanding the development of its climate. Ancient ocean temperatures are most commonly reconstructed by analysing the ratio of different oxygen atoms in the calcium carbonate remains of fossils. However, this presents many challenges, including a combination of biological processes known as “vital effects” which are very noticeable in corals and can affect the data. A research team led by the University of Göttingen now shows how the abundance of a third, very rare oxygen isotope can uncover whether the isotopic composition was solely influenced by temperature or if biological effects also played a role. The results were published in Geochemical Perspective Letters.

 

The hard structure of coral, known as the “coral skeleton”, is composed of calcium carbonate, the same material that makes up limestones. Corals, like all marine organisms, selectively incorporate different forms of oxygen. These different forms are called isotopes, meaning some oxygen atoms are lighter and some are heavier. At lower water temperatures, a higher abundance of the heavy oxygen isotope is incorporated into the carbonate structures. By analyzing the ratios of the heavy oxygen-18 isotope to the light oxygen-16 isotope in carbonates, scientists can calculate the ambient seawater temperatures of Earth's distant past. However, some carbonates, such as coral skeletons, return false temperatures because their oxygen isotope composition is also affected by the biological processes known as vital effects. The researchers have now discovered that a third, very rare isotope (oxygen-17) can be used to correct for these biological effects. As a result, researchers can now determine past ocean temperatures with greater accuracy, in addition to gaining more insights into the biomineralization processes of different coral species. Measurements of this rare oxygen-17 isotope, known in the field as the triple oxygen isotope method, in carbonates are normally very complicated. In fact, the stable isotope laboratory at the Göttingen University is among only a few in the world that can perform such analyses. The lab used cutting-edge instrumentation known as tuneable diode laser absorption spectroscopy.

 

“We used corals for our study as we know quite a lot about the processes by which they grow their skeletons,” said study leader, Dr David Bajnai at Göttingen University’s Geoscience Centre. “We are excited to apply this concept to other organisms commonly used in the study of Earth's past climate. We hope that triple oxygen isotope analyses will open up previously unusable datasets for paleoclimate research, enabling more accurate climate reconstructions, going further back in time.”

 

Professor Daniel Herwartz from the Ruhr University Bochum added, “We were also able to show that triple oxygen isotope analyses can inform us about the various processes we collectively call ‘vital effects’. For corals, we can now confirm that the main process involved is related to a chemical process called CO2 absorption, which we have independently studied in experiments. Such advanced techniques help to gain new insights into how organisms build their harder structures.”

 

Original publication: Bajnai, D. et al. “Correcting for vital effects in coral carbonate using triple oxygen isotopes”. Geochemical Perspectives Letters 2024. DOI: 10.7185/geochemlet.2430

 

Measuring temperatures from Earth’s past is important for understanding the development of its climate. Ancient ocean temperatures are most commonly reconstructed by analysing the ratio of different oxygen atoms in the calcium carbonate remains of fossils. However, this presents many challenges, including a combination of biological processes known as “vital effects” which are very noticeable in corals and can affect the data. A research team led by the University of Göttingen now shows how the abundance of a third, very rare oxygen isotope can uncover whether the isotopic composition was solely influenced by temperature or if biological effects also played a role. The results were published in Geochemical Perspective Letters.

 

The hard structure of coral, known as the “coral skeleton”, is composed of calcium carbonate, the same material that makes up limestones. Corals, like all marine organisms, selectively incorporate different forms of oxygen. These different forms are called isotopes, meaning some oxygen atoms are lighter and some are heavier. At lower water temperatures, a higher abundance of the heavy oxygen isotope is incorporated into the carbonate structures. By analyzing the ratios of the heavy oxygen-18 isotope to the light oxygen-16 isotope in carbonates, scientists can calculate the ambient seawater temperatures of Earth's distant past. However, some carbonates, such as coral skeletons, return false temperatures because their oxygen isotope composition is also affected by the biological processes known as vital effects. The researchers have now discovered that a third, very rare isotope (oxygen-17) can be used to correct for these biological effects. As a result, researchers can now determine past ocean temperatures with greater accuracy, in addition to gaining more insights into the biomineralization processes of different coral species. Measurements of this rare oxygen-17 isotope, known in the field as the triple oxygen isotope method, in carbonates are normally very complicated. In fact, the stable isotope laboratory at the Göttingen University is among only a few in the world that can perform such analyses. The lab used cutting-edge instrumentation known as tuneable diode laser absorption spectroscopy.

 

“We used corals for our study as we know quite a lot about the processes by which they grow their skeletons,” said study leader, Dr David Bajnai at Göttingen University’s Geoscience Centre. “We are excited to apply this concept to other organisms commonly used in the study of Earth's past climate. We hope that triple oxygen isotope analyses will open up previously unusable datasets for paleoclimate research, enabling more accurate climate reconstructions, going further back in time.”

 

Professor Daniel Herwartz from the Ruhr University Bochum added, “We were also able to show that triple oxygen isotope analyses can inform us about the various processes we collectively call ‘vital effects’. For corals, we can now confirm that the main process involved is related to a chemical process called CO2 absorption, which we have independently studied in experiments. Such advanced techniques help to gain new insights into how organisms build their harder structures.”

 

Original publication: Bajnai, D. et al. “Correcting for vital effects in coral carbonate using triple oxygen isotopes”. Geochemical Perspectives Letters 2024. DOI: 10.7185/geochemlet.2430

  

Image showing the coral Desmophyllum pertusum which was one of the species analysed by Göttingen University researchers to refine the method to measure temperatures from the past.

Credit

Helmholtz Centre for Ocean Research Kiel (GEOMAR) / JAGO Team Poseidon Cruise 391 Lopphavet Reef.

  

Image from the stable isotope laboratory at the Göttingen University, which is among only a few in the world that can perform such analyses. The researchers benefited from its cutting-edge instrumentation which enables the triple oxygen isotope analyses of CO2 gas used in this study. The laser spectrometer (the black box) and its custom-built peripherals are placed in a thermally insulated housing.

Credit

Dr David Bajnai

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Journal

Geochemical Perspectives Letters

DOI

10.7185/geochemlet.2430 

Method of Research

Experimental study

Subject of Research

Not applicable

Article Title

Correcting for vital effects in coral carbonate using triple oxygen isotopes

 

Study on planet-warming contrails “a spanner in the works” for aviation industry

CONTRAILS NOT CHEMTRAILS

Imperial College London

Modern commercial aircraft flying at high altitudes create longer-lived planet-warming contrails than older aircraft, a new study has found.

The result means that although modern planes emit less carbon than older aircraft, they may be contributing more to climate change through contrails.

Led by scientists at Imperial College London, the study highlights the immense challenges the aviation industry faces to reduce its impact on the climate. The new study also found that private jets produce more contrails than previously thought, potentially leading to outsized impacts on climate warming.

Contrails, or condensation trails, are thin streaks of cloud created by aircraft exhaust fumes that contribute to global warming by trapping heat in the atmosphere.

While the exact warming effect of contrails is uncertain, scientists believe it is greater than warming caused by carbon emissions from jet fuel.

Published today in Environmental Research Letters, the study used machine learning to analyse satellite data on more than 64,000 contrails from a range of aircraft flying over the North Atlantic Ocean.

Modern aircraft that fly at above 38,000 feet (about 12km), such as the Airbus A350 and Boeing 787 Airliners, create more contrails than older passenger-carrying commercial aircraft, the study found.

To reduce jet fuel consumption, modern aircraft are designed to fly at higher altitudes where the air is thinner with less aerodynamic drag, compared to older commercial aircraft, which usually fly at slightly lower altitudes (around 35,000ft/11km).

This means these higher-flying aircraft create less carbon emissions per passenger. However, it also means they create contrails that take longer to dissipate – creating a warming effect for longer and a complicated trade-off for the aviation industry.

Double whammy of warming

Dr Edward Gryspeerdt, the lead author of the study and a Royal Society University Research Fellow at the Grantham Institute – Climate Change and the Environment, said: “It's common knowledge that flying is not good for the climate. However, most people do not appreciate that contrails and jet fuel carbon emissions cause a double whammy warming of the climate.

“This study throws a spanner in the works for the aviation industry. Newer aircraft are flying higher and higher in the atmosphere to increase fuel efficiency and reduce carbon emissions.

“The unintended consequence of this is that these aircraft flying over the North Atlantic are now creating more, longer-lived, contrails, trapping additional heat in the atmosphere and increasing the climate impact of aviation.

“This doesn’t mean that more efficient aircraft are a bad thing – far from it, as they have lower carbon emissions per passenger-mile. However, our finding reflects the challenges the aviation industry faces when reducing its climate impact.”

The study did confirm a simple step that can be taken to shorten the lifetime of contrails: reduce the amount of soot emitted from aircraft engines, produced when fuel burns inefficiently.

Modern aircraft engines are designed to be cleaner, typically emit fewer soot particles, which cuts down the lifetime of contrails.

While other studies using models have predicted this phenomenon, the study published today is the first to confirm it using real-world observations.

Co-author Dr Marc Stettler, a Reader in Transport and the Environment in the Department of Civil and Environmental Engineering, Imperial College London, said: “From other studies, we know that the number of soot particles in aircraft exhaust plays a key role in the properties of newly formed contrails. We suspected that this would also affect how long contrails live for.

“Our study provides the first evidence that emitting fewer soot particles results in contrails that fall out of the sky faster compared to contrails formed on more numerous soot particles from older, dirtier engines.”

Private jets the worst offenders of contrails

Even higher in the sky, the researchers found that private jets create contrails more often than previously thought – adding to concerns about the excessive use of these aircraft by the super-rich.

Despite being smaller and using less fuel, private jets create similar contrails to much larger commercial aircraft, the analysis found, which surprised the researchers.

Private jets fly higher than other planes, more than 40,000 feet above earth where there is less air traffic. However, like modern commercial aircraft creating more contrails compared to lower-flying older commercial aircraft, the high altitudes flown by private jets means they create outsized contrails.

Dr Gryspeerdt said: “Despite their smaller size, private jets create contrails as often as much larger aircraft. We already know that these aircraft create a huge amount of carbon emissions per passenger so the super-rich can fly in comfort.

“Our finding adds to concerns about the climate impact caused by private jets as poor countries continue to get battered by extreme weather events.”

---

Journal

Environmental Research Letters

DOI

10.1088/1748-9326/ad5b78 

Article Title

Operational differences lead to longer lifetimes of satellite detectable contrails from more fuel efficient aircraft

Article Publication Date

7-Aug-2024

 

Urban concrete mines

Used concrete transformed into new bricks while trapping CO2, could see crumbling urban structures recycled into new buildings

Peer-Reviewed Publication

University of Tokyo

 

image: 

The new brick can be manufactured with a high density, compressive strength, tensile strength and Young's modulus (the ability to withstand changes under lengthwise compression).

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Credit: I. Maruyama, N.K. Bui, A. Meawad et al.

Researchers led by a team at the University of Tokyo have turned concrete from a demolished school building and carbon dioxide (CO2) from the air into new blocks strong enough to build a house with. The process involved grinding the old concrete into powder, reacting it with CO2 from the air, pressurizing it in layers in a mold and finally heating it to form the new block. Instead of making buildings from new concrete only, this technique could offer a way to recycle old materials while also trapping carbon dioxide in the process. The blocks could theoretically be remade again and again, through the same process.

A few years ago, researchers developed a new kind of concrete, which had the potential to reduce greenhouse gases and reuse waste from the construction industry. 

The project was named C4S, which stands for Calcium Carbonate Circulation System for Construction, and led by Professor Takafumi Noguchi, as project manager, with Professor Ippei Maruyama leading on material development. Both researchers are from the Department of Architecture at the University of Tokyo. Together with a team they developed a method to combine old concrete with carbon dioxide, taken from the air or industrial exhaust, to create a new, durable material called calcium carbonate concrete. However, the resulting blocks were only a few centimeters long.

 

Now, they have taken this technology to the next level. 

“We can make calcium carbonate concrete bricks large and strong enough to build regular houses and pavements,” said Maruyama. “These blocks can theoretically be used semipermanently through repeated crushing and remaking, a process which requires relatively low energy consumption. Now, concrete in old buildings can be thought of as a kind of urban mine for creating new buildings.”

Limestone is a key ingredient in Portland cement, which is typically used to make concrete. The rock provides durability and strength, while improving workability. However, limestone reserves are limited, and in some countries more than others, such as Japan. So attention is switching from creating new materials to maintaining and reusing what is already available.

“We are trying to develop systems that can contribute to a circular economy and carbon neutrality. In Japan, the current demand for construction material is less than in the past, so it is a good time to develop a new type of construction business, while also improving our understanding of this vital material through our research,” explained Maruyama.

Demolished concrete from a school building was crushed into a fine powder, sieved and then carbonated over three months. Carbonation is usually a slow, natural process which occurs when compounds in concrete, such as portlandite and calcium silicate hydrate, react with CO2 in the air to form calcium carbonate. The researchers performed a sped-up version of this process to recreate the same kind of concrete you would find in older buildings. This was to test that they could still make strong new blocks even from older concrete.

The carbonated powder was then pressurized with a calcium bicarbonate solution and dried. In their previous experiment, the team created calcium carbonate concrete by pouring a bicarbonate solution through carbonated concrete powder and heating it. In this updated version, as well as heating the material, the team built the concrete up in layers in a mold, which compacted it under pressure. They found this enhanced the strength of the blocks.

“As part of the C4S project, we intend to construct a real two-story house by 2030,” said Maruyama. “Over the next few years, we also plan to move to a pilot plant, where we can improve production efficiency and industrial application, and work on creating much larger building elements, as we move towards making this material commercially available.”

 

#####

Paper

I. Maruyama, N.K. Bui, A. Meawad, R. Kurihara, Y. Mitani, H. Hyodo, M. Kanematsu, T. Noguchi, Cold-sintered carbonated concrete waste fines: A calcium carbonate concrete block. 24 July 2024. Journal of Advanced Concrete Technology, 22 (2024) 406–418.

https://doi.org/10.3151/jact.22.406

 

Funding: This  article  is  based  on  results  obtained  from  a  project, JPNP18016 Research on C4S, Calcium Carbonate Circulation System for Construction,” commissioned by the New Energy and Industrial Technology Development Organization (NEDO).

 

Declaration/ conflicts of interest:

Taiheiyo Cement Corporation, Shimizu Corporation, and Masuo Recycle Co., Ltd. are collaborative members of the C4S project. 

Professor Ippei Maruyama is Editor in Chief of the Journal of Advanced Concrete Technology.

 

Useful Links

Graduate School of Engineering: https://www.t.u-tokyo.ac.jp/en/soe 

Building Material Engineering Lab: https://bme.t.u-tokyo.ac.jp/en/ 

[Press Release, June 2024] All-in-one method measures CO2 in concrete

https://www.u-tokyo.ac.jp/focus/en/press/z0508_00359.html 

[Press Release, November 2023] New method verifies carbon capture in concrete: https://www.u-tokyo.ac.jp/focus/en/press/z0508_00319.html 

[Press Release, October 2021] A concrete solution: https://www.u-tokyo.ac.jp/focus/en/press/z0508_00190.html

About the University of Tokyo

The University of Tokyo is Japan’s leading university and one of the world’s top research universities. The vast research output of some 6,000 researchers is published in the world’s top journals across the arts and sciences. Our vibrant student body of around 15,000 undergraduate and 15,000 graduate students includes over 4,000 international students. Find out more at www.u-tokyo.ac.jp/en/ or follow us on X (formerly Twitter) at @UTokyo_News_en.

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Journal

Journal of Advanced Concrete Technology

DOI

10.3151/jact.22.406 

Method of Research 

Experimental study

Subject of Research

Not applicable

Article Title

Cold-sintered carbonated concrete waste fines: A calcium carbonate concrete block

COI Statement

Taiheiyo Cement Corporation, Shimizu Corporation, and Masuo Recycle Co., Ltd. are collaborative members of the C4S project. Professor Ippei Maruyama is Editor in Chief of the Journal of Advanced Concrete Technology.

 

Giant prehistoric flying reptile took off using similar method to bats, study finds

University of Bristol

The pterosaur likely used all four limbs to propel itself in the air, as seen in bats today, researchers have found.

The findings, published today in PeerJ, provide new insights into how pterosaurs managed to take flight despite reaching sizes far larger than modern animals. The research sheds new light on the flight initiating jumping ability of these animals, some of which had wingspans of over ten meters.

The study, carried out by scientists at the University of Bristol, Liverpool John Moores University, Universidade Federal do ABC and the University of Keele, follows years of analysis and modelling of how muscles interact with bones to create movement in other animals and is now being used to start answering the question of how the largest flying animals known managed to get off the ground.

The team created the first computer model for this kind of analysis of a pterosaur to test three different ways pterosaurs may have taken off: a vertical burst jump using just the legs like those used by primarily ground-dwelling birds, a less vertical jump using just the legs more similar to the jump used by birds that fly frequently, and a four-limbed jump using its wings as well in a motion more like the take-off jump of a bat. By mimicking these motions, the researchers aimed to understand the leverage available to push the animal into the air.

“Larger animals have greater challenges to overcome in order to fly making the ability of animals as large as pterosaurs to do so especially fascinating.” Dr Ben Griffin, the lead author of the study, said. “Unlike birds which mainly rely on their hindlimbs, our models indicate that pterosaurs were more likely to rely on all four of their limbs to propel themselves into the air.”

This study examines one of the long-standing questions about the underlying biomechanics of pterosaur. This research not only enhances the understanding of pterosaur biology but also provides broader insights into the limits and dynamics of flight in large animals. By comparing pterosaurs with modern birds and bats, the study highlights the remarkable evolutionary solutions to the challenge of powered flight.

 

Paper:

‘Modelling take-off moment arms in an ornithocheiraean pterosaur’ by Ben Griffin et al in PeerJ.

 

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Journal

PeerJ

Method of Research

Computational simulation/modeling

Subject of Research

Animals

Article Title

Modelling take-off moment arms in an ornithocheiraean pterosaur

Article Publication Date

7-Aug-2024

 

Water delivered to the mantle by aluminum enriched hydrated slabs?

Velocities of aluminum enriched superhydrous phase B suggest the presence of hydrated mantle regions beneath subduction zones

Peer-Reviewed Publication

Ehime University

 

image: 

Schematic representation of the incorporation of aluminum together with water (as Al + H) in the crystal structure of superhydrous phase B.

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Credit: Geodynamics Research Center, Ehime University

Dense Hydrous Magnesium Silicates (DHMSs) are generally considered as primary water carriers from the shallow lithosphere to the deep mantle transition region (MTR; 410–660 km in depth). Among DHMSs, Superhydrous phase B (hereafter, SuB) holds the chemical formula, Mg10Si3H3O18. This phase is believed to hold a large amount of water and thus may have an important role in the water storage capacity of the MTR and the transportation of water to the deeper parts of the Earth’s interior; but because of its relative instability against the high temperature of the Earth’s mantle, SuB is generally associated with cold regions, such as the inner parts of the subducted slab. A recent experimental study conducted at Ehime University, however, showed that when aluminum incorporates SuB, its stability against temperature is drastically improved (Kakizawa et al., AmMin 2018), allowing this mineral to remain stable at pressure and temperature conditions matching those of the Earth’s lower mantle.

In 2022, the same  Ehime University research team reported the longitudinal (VP) and shear (VS) velocities of SuB (Xu et al., GRL 2022) using the X-ray and ultrasonic techniques implemented in a multi-anvil apparatus at the beamline BL04B1, located at the synchrotron facility, SPring-8, in Japan. The results showed that the presence of SuB could be correlated with the low seismic velocities observed in subducted slab regions. This time, they carried out similar high pressure and high temperature measurements on SuB samples doped with aluminum (Fig.1). Their new data suggest that incorporation of aluminum in SuB (Al-bearing SuB in Fig.2) promotes unusual variations of velocities with an increase in water content compared to the velocities of SuB without aluminum (Al-free SuB in Fig.2).

This new finding, in addition to the knowledge that the stability against temperature and capacity to store water of SuB are improved when aluminum is present in its structure, suggests that the Al-bearing SuB may account for seismically visible anomalies at the bottom of the MTR and beneath subduction zones in the uppermost lower mantle. These results should greatly contribute to tracing the existence and recycling of the former hydrated lithospheric crust in the Earth’s lower mantle and interpreting seismic velocities in terms of mantle composition, and estimate the amount of water that could be passed down to the deep mantle.

【Fig.2】Velocities of superhydrous phase B as a function of Al + H content 

Caption

Longitudinal (VP) and shear (VS) velocities of superhydrous phase B as function of Al + H content. Full symbols represent the aluminum-free SuB (Xu et al., 2022; Li et al., 2016; Rosa et al., 2015) while the open symbols are the aluminum bearing SuB of this study and Li et al. (2022).

Credit

Geodynamics Research Center, Ehime University

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Journal

Geophysical Research Letters

DOI

10.1029/2023GL107818