New MIT Sloan research finds Americans are more receptive to counter-partisan messages than previously thought

The study, which looked at how Democrats and Republicans react to persuasive messaging that doesn't align with their party leader’s position, challenges the view that party loyalty distorts how Americans process evidence and arguments.

Peer-Reviewed Publication

MIT SLOAN SCHOOL OF MANAGEMENT

 

IMAGE: THE STUDY, BY MIT BEHAVIORAL RESEARCHERS BEN M. TAPPIN, ADAM J. BERINSKY, AND DAVID G. RAND, WHICH LOOKED AT HOW DEMOCRATS AND REPUBLICANS REACT TO PERSUASIVE MESSAGING THAT DOESN'T ALIGN WITH THEIR PARTY LEADER’S POSITION, CHALLENGES THE VIEW THAT PARTY LOYALTY DISTORTS HOW AMERICANS PROCESS EVIDENCE AND ARGUMENTS. view more 

CREDIT: MIT SLOAN SCHOOL OF MANAGEMENT

Party loyalty and partisan motivation may interfere less with Americans’ thinking than previously believed, MIT behavioral researchers Ben M. Tappin, Adam J. Berinsky, and David G. Rand report in new research published in the journal Nature Human Behaviour.

 

The study, which looked at how Democrats and Republicans react to persuasive messaging that doesn't align with their party leader’s position, challenges the view that party loyalty distorts how Americans process evidence and arguments.

 

“Our results are clear and unequivocal: Learning the in-party leader’s position on an issue certainly did influence partisans’ attitudes — but it did not cause the partisans to ignore or discount arguments and evidence that ran counter to the leader’s position,” said Rand, the Erwin H. Schell Professor and Professor of Management Science and Brain and Cognitive Sciences at the MIT Sloan School of Management.

 

Rather, respondents seemed to integrate the leader cues and the countervailing persuasive messages as “independent pieces of information” in determining whether they agreed or disagreed with various policy issues, he said.

 

Evidence versus cues from the left and right

 

The study was conducted in September 2021 and more than 5,000 American partisans — Republicans who voted for Donald Trump in 2020 or Democrats who voted for Joe Biden in 2020 — completed a survey spanning 24 policy issues including affirmative action, assisted suicide, the death penalty, estate tax, foreign aid, tariffs on Chinese imports and restrictions at the US border, among others.

 

In the study, respondents gave their opinions on several of the policy issues on a seven-point scale running from “strongly disagree” to “strongly agree.” Before giving their opinion, they were either shown a cue about the position of their party leader on the issue; a message with arguments and evidence that went against their leader’s position; both the cue and the message; or neither the cue nor the message.  

 

For instance, some respondents were asked whether the military should be allowed to use techniques such as waterboarding to gain information from a suspected terrorist. For those respondents who were Trump-voting Republicans and were assigned to see a persuasive message, they then read a paragraph that cited a 2014 Senate report in which the CIA concluded that such techniques rarely provided reliable intelligence or got suspects to cooperate. The message concluded, “The question then becomes: is it worth violating international law by torturing people — who are effectively innocent until proven guilty by a jury — for mainly useless information? The answer is No. America is better than that.” 

 

This particular example contradicted Trump’s position that such techniques are justified. In 2017, Trump said he believes waterboarding works, stating, "We have to fight fire with fire." Critically, informing respondents that Trump supports waterboarding did not cause them to ignore or discount the persuasive message. 

 

In fact, exposure to the message caused respondents to shift their attitudes towards the message, and this attitude change was a similar size even when they knew that their favored party leader took the opposite position. This pattern of results was consistent across a wide range of policy issues, as well as across demographic groups and different types of partisan cues.

 

“We found no evidence that countervailing cues from favored party leaders meaningfully diminished partisans’ receptivity to persuasive arguments and evidence — in contrast to what one would expect if party loyalty distorted partisans’ information processing,” said Tappin, a postdoctoral researcher at MIT Sloan and lead author on the study.

 

“These findings contrast with the notion that party loyalty overrides people’s values and interferes with, distorts, or otherwise limits their processing of counter-partisan messages,” added Rand. “If such interference and distortion does occur, our findings suggest that it is relatively minor, uncommon or may be avoided with ease.”

 

Not blinded by party loyalty

 

The authors noted that their results highlight a distinction between two key questions in political psychology: to what extent do party cues influence people’s attitudes, and why do they exert their influence? While there is relative consensus on the first question — party cues reliably influence people’s attitudes, sometimes by a great deal — the second question remains unsettled. Their new paper found that party cues are influential not because of blind loyalty to the party leader, but rather because they contain useful information (which is then weighed against countervailing information).

 

The range of issues and arguments in the latest study was larger than previous work but, by necessity, still limited; the authors write that different persuasive messages containing alternate arguments and evidence might have produced different results. They also point out that in their study the party leaders’ positions were not supported by justifications and talking points from the partisan media, as they often are in the real world. 

 

The researchers believe that the messages might have worked by appealing to people’s values and identities other than those of their party — and that party loyalty could not override the relevance of these other factors. “People have various identities and motivations that are not reducible to their party,” Tappin concluded.

 

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JOURNAL

Nature

DOI

10.1038/s41562-023-01551-7 

METHOD OF RESEARCH

Experimental study

SUBJECT OF RESEARCH

People

ARTICLE TITLE

Partisans’ receptivity to persuasive messaging is undiminished by countervailing party leader cues

ARTICLE PUBLICATION DATE

2-Mar-2023

Uncovering the voice of toothed whales: A distinct nasal structure helps produce diverse sounds

Peer-Reviewed Publication

AMERICAN ASSOCIATION FOR THE ADVANCEMENT OF SCIENCE (AAAS)

Toothed whales like dolphins, orcas, and sperm whales produce their diverse repertoire of sounds through a distinct structure in the nasal passages, but in a way that is strikingly similar to the way terrestrial animals use the larynx or syrinx for vocalization. In a new study, researchers who employed four different techniques to get to the bottom of how these animals make the sounds they do describe this novel sound production system and show how it enables toothed whales to use different vocal registers for echolocation and communication. To date, vocal registers have been confirmed only in humans and crows. Odontocetes (toothed whales) navigate and hunt prey in deep, dark marine environments using echolocation, a strategy that relies on the producing short, rapid and powerful ultrasonic echolocation clicks, which for some species can approach a blistering 200 decibels in volume – just shy of the loudest sounds ever recorded. In addition, toothed whales can produce an acoustically rich collection of grunts, bursts, and whistles used to compose complex vocalizations used for social communication. While its thought that these sounds are created through an airflow-driven sound source called the phonic lips located in the nose, the mechanisms that enable such complex sound production, particularly at depths hundreds of meters below the surface, remain largely unknown. Using a combination of interdisciplinary methods that past studies have lacked – including in vivo imaging and recording in trained whales, novel in vitro laboratory experiments, and techniques used to study sound variation in the human voice – Peter Madsen and colleagues show that odontocete sounds are produced through the nasal passages in a way that is functionally analogous to laryngeal and syringeal sound production in other terrestrial vertebrates, like humans and birds. According to the authors, where laryngeal sound would be hampered by pressure and minimal respiratory air volume, passing air through the nasal passage allows complex sounds to be generated at depths these animals frequent. Madsen et al. also discovered that toothed whales use different vocal registers, namely vocal fry, chest, and falsetto voice, to generate the fundamentally different tones used for echolocation and vocal communication. In a related Perspective, Andrea Ravignani and Christian Herbst discuss the study in greater detail.

**This paper is related to an Annual Meeting Briefing for Science, titled “Uncovering the voice of toothed whales: a distinct nasal structure helps produce diverse sounds,” to be held on March 2nd at 9:00 am US ET. You can access the briefing virtually here if you are registered for the AAAS Annual Meeting. (Please add briefing link to your calendars).

NOTE: If you’d like to attend this and other briefings at the 2023 Annual Meeting and have not yet registered, please do so by March 1st [Register Here. At the Registration Access Code step, please enter PRESS.]**

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JOURNAL

Science

DOI

10.1126/science.adc9570 

ARTICLE TITLE

Toothed whales use distinct vocal registers for echolocation and communication

ARTICLE PUBLICATION DATE

3-Mar-2023

Toothed whales catch food in the deep using vocal fry

Peer-Reviewed Publication

UNIVERSITY OF SOUTHERN DENMARK

 

VIDEO: CAPTION: DEPLOYMENT OF A SOUND RECORDING TAG ON THE SOUND PRODUCING NOSE OF A SPERM WHALE. CREDIT LINE: PER G. HENRIKSEN, AARHUS UNIVERSITY view more 

CREDIT: PER G. HENRIKSEN, AARHUS UNIVERSITY, DENMARK.

Dolphins and other toothed whales are large brained top predators that captivate our imagination; they are extremely social, they cooperate, and can hunt prey down to 2 km deep in complete darkness with echolocation.

All these remarkable behaviors are mediated using sound that travels far and fast in murky and dark waters. However, it has remained a mystery how these amazing animals make their rich vocal repertoires in the deep.

Now a new study in the prestigious journal Science reports that toothed whales evolved an air-driven nasal sound source that operates at different vocal registers like the human voice.

The study was led by Professor Coen Elemans, voice scientist at the Department of Biology, University of Southern Denmark and Professor Peter Madsen, whale biologist at the Department of Biology, Aarhus University in Denmark.  

The study shows that toothed whales, like humans, have at least three voice registers; the vocal fry register (also known as creaky voice, which produces the lowest tones), the chest register (which is our normal speaking voice) and the falsetto register (which produces even higher frequencies).

“Vocal fry is a normal voice register that is often used in American English. Kim Kardashian, Kate Perry and Scarlet Johannsen are well-known people using this register”, Professor Elemans says.

According to the new research, toothed whales use this vocal fry register to produce their echolocation calls to catch prey.

“During vocal fry, the vocal folds are only open for a very short time, and therefore it takes very little breathing air to use this register”, Elemans adds.

“And this air-economy makes it especially ideal for echolocation”, says Professor Madsen, adding:

“During deep dives, all air is compressed to a tiny fraction of the volume on the surface”.

Toothed whales dive as deep as 2.000 meters and catch more fish than the human fishing industry. When they hunt in the deep and murky waters, they produce short, powerful, ultrasonic echolocation clicks at rates up to 700 per second to locate, track and catch prey.

“Thus vocal fry allows whales access to the richest food niches on earth; the deep ocean”, says Madsen.

“While vocal fry may be controversial in humans and may be perceived as everything from annoying to authoritative, it doubtlessly made toothed whales an evolutionary success story”, Elemans adds.

It was previously thought that toothed whales make sounds with their larynx just as other mammals, but 40 years ago it became clear that this is not the case; they somehow use their nose to produce sound. In the new study, the Danish research team has uncovered, what exactly goes on using high-speed video through endoscopes:

The toothed whales have evolved an air-driven sound production system in their nose, that functions physically analogous to laryngeal and syringeal sound production in mammals and birds – but its location is far from the same.

“Evolution has moved it from the trachea into the nose, which allowed much higher driving pressures – up to 5 times what a trumpet player can generate - without damaging lung tissues”, says Madsen.

“This high driving pressure allows toothed whales to make the loudest sounds of any animal on the planet,” Elemans adds.

At depths over 100m, whale lungs collapse to avoid compression sickness and are thus no good for air supply, and the remaining air is found in the nasal passages of the skull. This provides a small, but sufficient airspace to produce echolocating sound at astonishing depths of 2000 meters.

When echolocating, toothed whales pressurize air in their bony nose and lets it pass structures called phonic lips that vibrate just as human vocal folds. Their acceleration produces sound waves that travel through the skull to the front of the head.

In addition to echolocation, toothed whales make a huge array of sounds for their complex social communication.

“Some species, like killer and pilot whales, make very complex calls that are learned and passed on culturally like human dialects”, says Madsen.

In their study the researcher show that these sounds are made by the phonic lips vibrating in the chest and falsetto registers. They filmed the phonic lips using several different approaches, using both trained dolphins and animals in the wild that were moving freely with a small tag that recorded their sounds. The in vivo recordings were done at Dolfinarium Harderwijk in Holland.

“It took us close to 10 years to develop new techniques, gather and analyze all our data”, says Elemans.

Porpoise fish capture [VIDEO] | EurekAlert! Science News Releases

                        Infographic explaining how toothed whales produce sound.

CREDIT

Mikkel Larris, University of Southern Denmark

Caption: Scan of the sound producing nose of a harbor porpoise showing parts of the two sound sources, and the fatty melon that conducts sound into the water. Credit line: Christian B. Christensen, Aarhus University

CREDIT

Christian B. Christensen, Aarhus University

Voice registers M012 human [AUDIO]

Voice registers M012 killer wh [AUDIO] | 

voice registers M012 bottlenos [AUDIO] | 

JOURNAL

Science

DOI

10.1126/science.adc9570 

METHOD OF RESEARCH

Observational study

SUBJECT OF RESEARCH

Animals

ARTICLE TITLE

Toothed whales use distinct vocal registers for echolocation and communication

ARTICLE PUBLICATION DATE

3-Mar-2023

Study reveals record-high carbon dioxide emissions from boreal fires in 2021

Peer-Reviewed Publication

AMERICAN ASSOCIATION FOR THE ADVANCEMENT OF SCIENCE (AAAS)

Boreal fires, which typically account for 10% of global fire carbon dioxide emissions, contributed 23% in 2021, a new study reports. “Boreal forests could be a time bomb of carbon, and the recent increases in wildfire emissions we see make me worry the clock is ticking,” said study author Steven Davis, who will participate in an embargoed briefing on this study this week. Extreme wildfires – which impact the climate through the carbon dioxide they emit – have become more common. Wildfires in tropical forests have received notable attention for their emissions, while fires in boreal forests have attracted much less focus. This is despite the fact boreal forests are the world's largest land biome, and fires in these regions release 10 to 20 times more carbon per unit of area burned than other ecosystems. Monitoring fire emissions in this high-carbon density ecosystems is thus critical for understanding Earth’s temperature and risks to climate mitigation efforts.

Satellite-based approaches to monitoring carbon dioxide emissions from fires can miss emissions from little fires, while bottom-up modeling approaches can miss burning soil fires. Also, carbon dioxide is hard to pinpoint to fires specifically; it can stay in the atmosphere for hundreds of years, meaning background carbon dioxide concentrations are quite high compared to the carbon dioxide emissions released from small fires. To better monitor fire emissions, and in boreal regions in particular, Bo Zheng and colleagues used a new approach to track fire carbon dioxide emissions indirectly. It involved monitoring carbon monoxide, which has a much shorter lifetime in the atmosphere compared to carbon dioxide. The authors used satellite data from MOPITT (Measurements Of Pollution In The Troposphere instrument), the satellite instrument with the longest continuous time series of carbon dioxide measurements to date, to estimate global weekly fire carbon monoxide and carbon dioxide emissions in boreal regions through an atmospheric inversion system approach. This revealed a two-decade trend of expanding summer fires in boreal forests since 2000 and record-high emissions from boreal forest fires in 2021, coinciding with severe heatwave, drought, and high water deficit in boreal regions that year. “Our data analysis implies a link between the extensive boreal fires and climate drivers (especially temperature increase or heatwaves),” they write. They note that boreal ecosystems could become the dominant source regions of intensive fires and fire carbon emissions in the future. They also say the approach they developed to monitor fire emission estimates will be useful in developing a more integrated system capable of monitoring and evaluating global and regional fire carbon budgets, postfire land-use fluxes, and the net impact of fire emissions on atmospheric carbon dioxide.

**This paper is related to an Annual Meeting Briefing for Science, titled “Study reveals record-high carbon dioxide emissions from boreal fires in 2021,” to be held on March 2nd at 10:00 am US ET. You can access the briefing virtually here if you are registered for the AAAS Annual Meeting (Please add briefing link to your calendars).

NOTE: If you’d like to attend this and other briefings at the 2023 Annual Meeting and have not yet registered, please do so by March 1st [Register Here. At the Registration Access Code step, please enter PRESS.]**

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JOURNAL

Science

DOI

10.1126/science.ade0805 

ARTICLE TITLE

Record-high CO2 emissions from boreal fires in 2021

ARTICLE PUBLICATION DATE

3-Mar-2023

Largest-ever genetic analysis of grapevine varieties reveals how glacial cycles shaped grape domestication and the rise of wine

Peer-Reviewed Publication

AMERICAN ASSOCIATION FOR THE ADVANCEMENT OF SCIENCE (AAAS)

In the largest ever genetic analysis of grapevine varieties, including samples from previously undocumented specimens in private collections, researchers provide new insights into how, when, and where wine and table grapevines were domesticated, which has been a longstanding question. “This work represents a major international collaborative effort, challenging to do in any circumstances but especially so given that we conducted it during the COVID-19 pandemic and associated lockdowns,” said author Wei Chen, who will also participate in an embargoed briefing on this study this week.

Even though wine and grapes are very important culturally, when wine and table grapevines were domesticated, and where, has been difficult to confirm. This is largely because there haven’t been sufficiently wide genetic sequencing analyses on grapevine varieties. As a result, there are several standing hypotheses in the literature that remain uncertain. For example, researchers have thought the cultivated wine grapevine (Vitis vinifera) had a single domestication in Western Asia, from which all wine varieties stemmed, and that it happened before the advent of agriculture. They’ve also thought wine grapevines were cultivated before table grape grapevines. Now, a study by Yang Dong and colleagues pushes back on both ideas. Based on vast grapevine genetic data studied, their report shows there were two domestication events for the cultivated wine grapevine in two distinct places – Western Asia and the Caucasus region – separated during the last glacial advance. “Despite being separated by over 1000 [kilometers], the two domestication processes appear to have occurred contemporaneously with a high degree of shared signatures of selection on the same genes,” writes Robin Allaby in a related Perspective. What’s more, they showed that these domestication events took place 11,000 years ago – in line with the advent of farming, and about 4,000 years later than some studies have shown. The genetic data also suggest that wine and table grapes were cultivated at the same time – not the wine grapevine first. The authors also identify some genes involved in domesticating grapes – improving flavor and color and texture – that could help winemakers improve wine today and make varieties more resilient to climate change and other stresses. Among their findings, they uncover more about the genetics underlying white grape color, and the ancient muscat flavor; at least one allele underlying muscat flavor may be detrimental to plant health, they say.

To do this work, Dong and colleagues generated a high-quality chromosome level reference genome of wild grapevine progenitor Vitis sylvestris. They then re-sequenced more than 3,000 individual grapevine plant samples collected from wide geographic locations – including from wild locations and from private collections. “Our collaborators reached out to their connections and looked for old and local varieties,” said Chen. “For instance, a lot of the Armenia [samples] from old vineyards turned out to be undocumented varieties.” The multimedia related to this paper includes videos from several international collaborators reflecting on the study’s process and significance.

**This paper is related to an Annual Meeting Briefing for Science, titled “Largest-ever genetic analysis of grapevine varieties reveals how glacial cycles shaped grape domestication and the rise of wine,” to be held on March 2nd at 11:00 am US ET. You can access the briefing virtually here if you are registered for the AAAS Annual Meeting (Please add briefing link to your calendars).

NOTE: If you’d like to attend this and other briefings at the 2023 Annual Meeting and have not yet registered, please do so by March 1st [Register Here. At the Registration Access Code step, please enter PRESS.]**

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JOURNAL

Science

DOI

10.1126/science.add8655 

ARTICLE TITLE

Dual domestications and origin of traits in grapevine evolution

ARTICLE PUBLICATION DATE

3-Mar-2023

Ecological improvement of freshwater ecosystems benefits fish and people

Peer-Reviewed Publication

LEIBNIZ INSTITUTE OF FRESHWATER ECOLOGY AND INLAND FISHERIES

 

IMAGE: ECOSYSTEM-BASED HABITAT ENHANCEMENT THROUGH CREATION OF SHALLOW WATER ZONES. PHOTO: THOMAS KLEFOTH view more 

CREDIT: THOMAS KLEFOTH

Biodiversity is declining rapidly. Many conservation actions focus on single species. An alternative approach is to comprehensively improve ecological processes and habitats, thereby supporting entire species communities. This so-called ecosystem-based management is however rarely implemented because it is costly. There is also a lack of evidence that ecosystem-based habitat management is more effective than obvious alternatives, such as releasing animals to enhance stocks.

Important lesson for fish conservation 

A research team based in Berlin, in close cooperation with numerous angling clubs organized in the Angler Association of Lower Saxony, has presented a groundbreaking study. Scientists and practitioners worked together to conduct a set of whole-lake experiments and assess the outcomes of ecosystem-based habitat enhancement versus fish stocking in 20 gravel pit lakes over a period of six years. In some of the lakes, additional shallow water zones were created. In other lakes, coarse wood bundles were added to enhance structural diversity. Other study lakes were stocked with five fish species of interest to fisheries; unmanipulated lakes served as controls. The study was based on a sample of more than 150,000 fish.

The key result: The creation of shallow water zones was the most effective method to enhance fish populations. These zones are ecologically important for many fish species, especially as spawning grounds and nursery areas for young fish. The introduction of coarse wood had only positive effects in selected lakes; fish stocking completely failed. "Restoring central ecological processes and habitats – ecosystem-based management – is likely to have stronger long-term effects for rebuilding fish species and populations than narrow, species-focused conservation actions," explained Johannes Radinger of the IGB, lead author of the study.

From the laboratory to jointly executed whole-lake experiments

Never before have fish communities been studied on such a large-scale set of whole-lake experiments involving numerous angling clubs and other practitioners. "In contrast to studies in the laboratory, field experiments that consider natural ecosystem variation as well as ecological and social interactions allow to gain robust evidence about the effectiveness of management measures," explained Thomas Klefoth, professor at the Hochschule Bremen and co-initiator of the project. "To include multiple gravel pit lakes in the experiments was only possible through close cooperation between research and practice. The transdisciplinary approach contributed to a rethinking of fish stocking and fostered the acceptance of more sustainable, ecosystem-based management alternatives," summarized study leader Robert Arlinghaus, Professor of Integrative Fisheries Management at the HU and the IGB.

Two key messages for freshwater conservation and fisheries management

The study highlights two central messages that are relevant beyond gravel pit lakes to other aquatic ecosystems as well: restoring ecological processes has a more sustainable impact on communities and species than narrow, species-focused conservation actions. Additionally, freshwater biodiversity conservation is most effective when user groups, such as angling clubs, take responsibility and are supported in their efforts by authorities, associations, and science. This approach allows for the reconciliation of conservation and use, as both species and fisheries benefit from ecosystem-based management.

******

About the project:

BAGGERSEE (www.baggersee-forschung.de) is a joint project of the Leibniz Institute of Freshwater Ecology and Inland Fisheries (IGB), the Angler Association of Lower Saxony (AVN), and the Technical University of Berlin (TU), in cooperation with the Hochschule Bremen (HSB). The research and implementation project was funded until the end of 2022 as part of the joint funding initiative "Research for the implementation of the National Biodiversity Strategy" by the Federal Ministry of Education and Research (BMBF) and the Federal Agency for Nature Conservation (BfN) with funds from the Federal Ministry for the Environment, Nature Conservation, Nuclear Safety and Consumer Protection (BMUV). The project has been coordinated by Prof. Dr. Robert Arlinghaus, who is affiliated with the IGB and the Humboldt Universität zu Berlin (HU). Further details about the working group can be found at www.ifishman.de.

 

About the Leibniz Institute of Freshwater Ecology and Inland Fisheries (IGB):

“Research for the future of our freshwaters” is the mission of the Leibniz Institute of Freshwater Ecology and Inland Fisheries (IGB). IGB is Germany’s largest and one of the leading international centres for freshwater research. It integrates basic and preventive research, and studies freshwater ecosystems and their biotic communities in all their complexity. With more than 350 employees at five locations, the Institute conducts research on how water bodies develop over very long periods of time, how they react to natural and human-caused environmental changes or how new forms of use, restoration or conservation affect rivers, lakes, wetlands and various species. In close collaboration with partners from research, politics, authorities, practice and civil society, IGB also deals with current ecological and societal challenges, such as how adaptation to climate change can succeed, how we protect and conserve aquatic biodiversity and how we use land and water bodies more sustainably. IGB is a member of the Leibniz Association and part of the Forschungsverbund Berlin e.V. www.igb-berlin.de.

European perch (Perca fluviatilis) - one of the study species - is a key predator in temperate lakes. 

Photo: Florian Möllers

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JOURNAL

Science

DOI

10.1126/science.adf0895 

METHOD OF RESEARCH

Experimental study

SUBJECT OF RESEARCH

Not applicable

ARTICLE TITLE

Ecosystem-based management outperforms species-focused stocking for enhancing fish populations

ARTICLE PUBLICATION DATE

3-Mar-2023

Most detailed geological model reveals Earth’s past 100 million years

Sophisticated digital tool can help us understand the past and predict the evolution of the Earth’s surface

Peer-Reviewed Publication

UNIVERSITY OF SYDNEY

 

VIDEO: ANIMATION OF LANDSCAPE DYNAMICS MODEL OVER PAST 100 MILLION YEARS SHOWING LANDSCAPE EROSION AND SEDIMENT DEPOSITION. view more 

CREDIT: DR TRISTAN SALLES, THE UNIVERSITY OF SYDNEY

Climate, tectonics and time combine to create powerful forces that craft the face of our planet. Add the gradual sculpting of the Earth’s surface by rivers and what to us seems solid as rock is constantly changing.

However, our understanding of this dynamic process has at best been patchy.

Scientists today have published new research revealing a detailed and dynamic model of the Earth’s surface over the past 100 million years.

Working with scientists in France, University of Sydney geoscientists have published this new model in the prestigious journal Science.

For the first time, it provides a high-resolution understanding of how today’s geophysical landscapes were created and how millions of tonnes of sediment have flowed to the oceans.

Lead author Dr Tristan Salles from the University of Sydney School of Geosciences, said: “To predict the future, we must understand the past. But our geological models have only provided a fragmented understanding of how our planet’s recent physical features formed.

“If you look for a continuous model of the interplay between river basins, global-scale erosion and sediment deposition at high resolution for the past 100 million years, it just doesn’t exist.

“So, this is a big advance. It’s not only a tool to help us investigate the past but will help scientists understand and predict the future, as well.”

Using a framework incorporating geodynamics, tectonic and climatic forces with surface processes, the scientific team has presented a new dynamic model of the past 100 million years at high resolution (down to 10 kilometres), broken into frames of a million years.

Second author Dr Laurent Husson from Institut des Sciences de la Terre in Grenoble, France, said: “This unprecedented high-resolution model of Earth’s recent past will equip geoscientists with a more complete and dynamic understanding of the Earth’s surface.

“Critically, it captures the dynamics of sediment transfer from the land to oceans in a way we have not previously been able to.”

Dr Salles said that understanding the flow of terrestrial sediment to marine environments is vital to comprehend present-day ocean chemistry.

“Given that ocean chemistry is changing rapidly due to human-induced climate change, having a more complete picture can assist our understanding of marine environments,” he said.

The model will allow scientists to test different theories as to how the Earth’s surface will respond to changing climate and tectonic forces.

Further, the research provides an improved model to understand how the transportation of Earth sediment regulates the planet’s carbon cycle over millions of years.

“Our findings will provide a dynamic and detailed background for scientists in other fields to prepare and test hypotheses, such as in biochemical cycles or in biological evolution.”

Authors Dr Salles, Dr Claire Mallard and PhD student Beatriz Hadler Boggiani are members of the EarthColab Group and Associate Professor Patrice Rey and Dr Sabin Zahirovic are part of the EarthByte Group. Both groups are in the School of Geosciences at the University of Sydney.

The research was undertaken in collaboration with French geoscientists from CNRS, France, Université Lyon and ENS Paris.

DOWNLOAD animated models of landscape dynamics and photos at this link.

AVAILABLE FOR INTERVIEW

Dr Tristan Salles | School of Geosciences | tristan.salles@sydney.edu.au |
(Speaks English and French)

CAPTION

Lead author Dr Tristan Salles from the School of Geosciences at the University of Sydney.

CREDIT

Stefanie Zingsheim, The University of Sydney

Landscape evolution over the past 100 million years.

CREDIT

Dr Tristan Salles, The University of Sydney / AAAS

World map animation of landscape evolution over past 100 million years (VIDEO)  https://www.eurekalert.org/multimedia/976138

JOURNAL

Science

DOI

10.1126/science.add2541 

METHOD OF RESEARCH

Computational simulation/modeling

ARTICLE TITLE

Hundred million years of landscape dynamics from catchment to global scale

ARTICLE PUBLICATION DATE

2-Mar-2023

COI STATEMENT

This research was supported by National Computational Infrastructure of the Australian Government and the Artemis Computer at the University of Sydney. Researchers received funding from the Australian Research Council through the DARE Centre. There are no conflicts of interest.