Thursday, April 01, 2021

First interstellar comet may be the most pristine ever found

ESO

IMAGE: THIS IMAGE WAS TAKEN WITH THE FORS2 INSTRUMENT ON ESO'S VERY LARGE TELESCOPE IN LATE 2019, WHEN COMET 2I/BORISOV PASSED NEAR THE SUN. SINCE THE COMET WAS TRAVELLING AT BREAKNECK SPEED,... view more
CREDIT: ESO/O. HAINAUT

New observations with the European Southern Observatory's Very Large Telescope (ESO's VLT) indicate that the rogue comet 2I/Borisov, which is only the second and most recently detected interstellar visitor to our Solar System, is one of the most pristine ever observed. Astronomers suspect that the comet most likely never passed close to a star, making it an undisturbed relic of the cloud of gas and dust it formed from.

2I/Borisov was discovered by amateur astronomer Gennady Borisov in August 2019 and was confirmed to have come from beyond the Solar System a few weeks later. "2I/Borisov could represent the first truly pristine comet ever observed," says Stefano Bagnulo of the Armagh Observatory and Planetarium, Northern Ireland, UK, who led the new study published today in Nature Communications. The team believes that the comet had never passed close to any star before it flew by the Sun in 2019.

Bagnulo and his colleagues used the FORS2 instrument on ESO's VLT, located in northern Chile, to study 2I/Borisov in detail using a technique called polarimetry [1]. Since this technique is regularly used to study comets and other small bodies of our Solar System, this allowed the team to compare the interstellar visitor with our local comets.

The team found that 2I/Borisov has polarimetric properties distinct from those of Solar System comets, with the exception of Hale-Bopp. Comet Hale-Bopp received much public interest in the late 1990s as a result of being easily visible to the naked eye, and also because it was one of the most pristine comets astronomers had ever seen. Prior to its most recent passage, Hale-Bopp is thought to have passed by our Sun only once and had therefore barely been affected by solar wind and radiation. This means it was pristine, having a composition very similar to that of the cloud of gas and dust it -- and the rest of the Solar System -- formed from some 4.5 billion years ago.

By analysing the polarisation together with the colour of the comet to gather clues on its composition, the team concluded that 2I/Borisov is in fact even more pristine than Hale-Bopp. This means it carries untarnished signatures of the cloud of gas and dust it formed from.

"The fact that the two comets are remarkably similar suggests that the environment in which 2I/Borisov originated is not so different in composition from the environment in the early Solar System," says Alberto Cellino, a co-author of the study, from the Astrophysical Observatory of Torino, National Institute for Astrophysics (INAF), Italy.

Olivier Hainaut, an astronomer at ESO in Germany who studies comets and other near-Earth objects but was not involved in this new study, agrees. "The main result -- that 2I/Borisov is not like any other comet except Hale-Bopp -- is very strong," he says, adding that "it is very plausible they formed in very similar conditions."

"The arrival of 2I/Borisov from interstellar space represented the first opportunity to study the composition of a comet from another planetary system and check if the material that comes from this comet is somehow different from our native variety," explains Ludmilla Kolokolova, of the University of Maryland in the US, who was involved in the Nature Communications research.

Bagnulo hopes astronomers will have another, even better, opportunity to study a rogue comet in detail before the end of the decade. "ESA is planning to launch Comet Interceptor in 2029, which will have the capability of reaching another visiting interstellar object, if one on a suitable trajectory is discovered," he says, referring to an upcoming mission by the European Space Agency.

An origin story hidden in the dust

Even without a space mission, astronomers can use Earth's many telescopes to gain insight into the different properties of rogue comets like 2I/Borisov. "Imagine how lucky we were that a comet from a system light-years away simply took a trip to our doorstep by chance," says Bin Yang, an astronomer at ESO in Chile, who also took advantage of 2I/Borisov's passage through our Solar System to study this mysterious comet. Her team's results are published in Nature Astronomy.

Yang and her team used data from the Atacama Large Millimeter/submillimeter Array (ALMA), in which ESO is a partner, as well as from ESO's VLT, to study 2I/Borisov's dust grains to gather clues about the comet's birth and conditions in its home system.

They discovered that 2I/Borisov's coma -- an envelope of dust surrounding the main body of the comet -- contains compact pebbles, grains about one millimetre in size or larger. In addition, they found that the relative amounts of carbon monoxide and water in the comet changed drastically as it neared the Sun. The team, which also includes Olivier Hainaut, says this indicates that the comet is made up of materials that formed in different places in its planetary system.

The observations by Yang and her team suggest that matter in 2I/Borisov's planetary home was mixed from near its star to further out, perhaps because of the existence of giant planets, whose strong gravity stirs material in the system. Astronomers believe that a similar process occurred early in the life of our Solar System.

While 2I/Borisov was the first rogue comet to pass by the Sun, it was not the first interstellar visitor. The first interstellar object to have been observed passing by our Solar System was ?Oumuamua, another object studied with ESO's VLT back in 2017. Originally classified as a comet, ?Oumuamua was later reclassified as an asteroid as it lacked a coma.

Notes

[1] Polarimetry is a technique to measure the polarisation of light. Light becomes polarised, for example, when it goes through certain filters, like the lenses of polarised sunglasses or cometary material. By studying the properties of sunlight polarised by a comet's dust, researchers can gain insights into the physics and chemistry of comets.

More information

This research highlighted in the first part of this release was presented in the paper "Unusual polarimetric properties for interstellar comet 2I/Borisov" to appear in Nature Communications (doi: [10.1038/s41467-021-22000-x] - https://www.nature.com/articles/s41467-021-22000-x ). The second part of the release highlights the study "Compact pebbles and the evolution of volatiles in the interstellar comet 2I/Borisov" to appear in Nature Astronomy (doi: [10.1038/s41550-021-01336-w] - https://www.nature.com/articles/s41550-021-01336-w ).

The team who conducted the first study is composed of S. Bagnulo (Armagh Observatory & Planetarium, UK [Armagh]), A. Cellino (INAF - Osservatorio Astrofisico di Torino, Italy), L. Kolokolova (Department of Astronomy, University of Maryland, US), R. Ne�ič (Armagh; Mullard Space Science Laboratory, University College London, UK; Centre for Planetary Science, University College London/Birkbeck, UK), T. Santana-Ros (Departamento de Fisica, Ingeniería de Sistemas y Teoría de la Señal, Universidad de Alicante, Spain; Institut de Ciencies del Cosmos, Universitat de Barcelona, Spain), G. Borisov (Armagh; Institute of Astronomy and National Astronomical Observatory, Bulgarian Academy of Sciences, Bulgaria), A. A. Christou (Armagh), Ph. Bendjoya (Université Côte d'Azur, Observatoire de la Côte d'Azur, CNRS, Laboratoire Lagrange, Nice, France), and M. Devogele (Arecibo Observatory, University of Central Florida, US).

The team who conducted the second study is composed of Bin Yang (European Southern Observatory, Santiago, Chile [ESO Chile]), Aigen Li (Department of Physics and Astronomy, University of Missouri, Columbia, USA), Martin A. Cordiner (Astrochemistry Laboratory, NASA Goddard Space Flight Centre, USA and Department of Physics, Catholic University of America, Washington, DC, USA), Chin-Shin Chang (Joint ALMA Observatory, Santiago, Chile [JAO]), Olivier R. Hainaut (European Southern Observatory, Garching, Germany), Jonathan P. Williams (Institute for Astronomy, University of Hawai'i, Honolulu, USA [IfA Hawai'i]), Karen J. Meech (IfA Hawai'i), Jacqueline V. Keane (IfA Hawai'i), and Eric Villard (JAO and ESO Chile).

ESO is the foremost intergovernmental astronomy organisation in Europe and the world's most productive ground-based astronomical observatory by far. It has 16 Member States: Austria, Belgium, the Czech Republic, Denmark, France, Finland, Germany, Ireland, Italy, the Netherlands, Poland, Portugal, Spain, Sweden, Switzerland and the United Kingdom, along with the host state of Chile and with Australia as a Strategic Partner. ESO carries out an ambitious programme focused on the design, construction and operation of powerful ground-based observing facilities enabling astronomers to make important scientific discoveries. ESO also plays a leading role in promoting and organising cooperation in astronomical research. ESO operates three unique world-class observing sites in Chile: La Silla, Paranal and Chajnantor. At Paranal, ESO operates the Very Large Telescope and its world-leading Very Large Telescope Interferometer as well as two survey telescopes, VISTA working in the infrared and the visible-light VLT Survey Telescope. Also at Paranal ESO will host and operate the Cherenkov Telescope Array South, the world's largest and most sensitive gamma-ray observatory. ESO is also a major partner in two facilities on Chajnantor, APEX and ALMA, the largest astronomical project in existence. And on Cerro Armazones, close to Paranal, ESO is building the 39-metre Extremely Large Telescope, the ELT, which will become "the world's biggest eye on the sky".

The Atacama Large Millimeter/submillimeter Array (ALMA), an international astronomy facility, is a partnership of ESO, the U.S. National Science Foundation (NSF) and the National Institutes of Natural Sciences (NINS) of Japan in cooperation with the Republic of Chile. ALMA is funded by ESO on behalf of its Member States, by NSF in cooperation with the National Research Council of Canada (NRC) and the Ministry of Science and Technology (MOST) and by NINS in cooperation with the Academia Sinica (AS) in Taiwan and the Korea Astronomy and Space Science Institute (KASI). ALMA construction and operations are led by ESO on behalf of its Member States; by the National Radio Astronomy Observatory (NRAO), managed by Associated Universities, Inc. (AUI), on behalf of North America; and by the National Astronomical Observatory of Japan (NAOJ) on behalf of East Asia. The Joint ALMA Observatory (JAO) provides the unified leadership and management of the construction, commissioning and operation of ALMA.

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Links

* Research papers:

* Bagnulo et. al, Nature Communications - https://www.eso.org/public/archives/releases/sciencepapers/eso2106/eso2106a.pdf

* Yang et. al, Nature Astronomy - https://www.eso.org/public/archives/releases/sciencepapers/eso2106/eso2106b.pdf

* Photos of the VLT - http://www.eso.org/public/images/archive/category/paranal/

* Photos of the ALMA - https://www.eso.org/public/images/archive/category/alma/

Friends and enemies 'make sense' for long-lived animals

UNIVERSITY OF EXETER

Research News

IMAGE: HYENAS ARE SLOW-LIVED AND HAVE COMPLEX SOCIAL STRUCTURES view more
CREDIT: DAVE HUDSON

It makes evolutionary sense for long-lived animals to have complex social relationships - such as friends and enemies - researchers say.

Some species and individuals focus their energy on reproduction (live fast, die young), while "slow-living" animals prioritise survival and tend to live longer lives.

In the new paper, University of Exeter scientists argue that natural selection favours complex social structures among slow-living animals - meaning that knowing their friends and enemies is easier for animals with longer lifespans, and helps them live even longer.

Meanwhile, fast-lived species should only bother with such social relationships if it increases their chances of reproduction.

"Slow-living species can afford to invest in social relationships, as they live long enough to enjoy the pay-offs," said Professor Dave Hodgson, Director of the Centre for Ecology and Conservation on Exeter's Penryn Campus in Cornwall.

"There is strong evidence that strong social bonds are beneficial for survival in slow-living species, including humans.

"We suggest there is a 'positive feedback' - certain social behaviours lead to a longer life, and longer lifespan promotes the development of social bonds."

Professor Hodgson said there is "growing evidence" that differentiated social relationships have a bigger positive effect on survival than on reproduction.

As a result, fast-lived species do not gain the same evolutionary advantages from social relationships as slow-lived species.

Examples of fast-living species could include shrews and crickets, while animals such as mongooses, badgers and hyenas, and indeed humans, have a slower "pace of life".

Pace of life measurements take body size into account. Larger animals tend to live longer, but pace of life can vary significantly in two species of similar size.

Dr Matthew Silk, also of the University of Exeter, said: "If we want to understand more about social relationships and lifespan, we need to think about the relationship between the two.

"More research is needed to explore the social structures of wild animals.

"This could help us understand the links between social bonds, survival and reproduction."

Professor Hodgson said: "Our proposal, that strong and weak social bonds will be more prevalent in slower-living animals, is theoretical.

"We know a lot about animal lifespans, but we know too little about the social structures of many types of animal.

"If we are right, then social bonds could really be key to longer life."

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The paper, published in the journal Trends in Ecology and Evolution, is entitled: "Differentiated social relationships and the pace-of-life-history."

The neural mechanism of a circulatory response to stress

Researchers from the University of Tsukuba discover a novel mechanism by which the brain regulates the cardiovascular system in response to stress

UNIVERSITY OF TSUKUBA

Research News

Tsukuba, Japan - Although the heart beats autonomously, its function can be regulated by the brain in response to, for instance, stressful events. In a new study, researchers from the University of Tsukuba discovered a novel mechanism by which a specific part of the brain, the lateral habenula (LHb), regulates the cardiovascular system.

The cardiovascular system, specifically the heart and blood vessels, have a certain autonomy that allows them to function independently from the brain. In order for the individual to adapt to new, potentially threatening situations, the brain does have some regulatory power over the cardiovascular system. This is achieved by controlling the autonomic nervous system, which consists of the sympathetic and parasympathetic system. While the former has a stimulating effect on the cardiovascular system, including increasing the heart rate and blood pressure, the latter causes the opposite.

"From an evolutionary standpoint, the brain has had in incredibly important function in protecting the individual from predators," says lead author of the study Professor Tadachika Koganezawa. "But even in the absence of predators, our bodies react to stressful situations. In this study, we wanted to determine how the brain regulated the cardiovascular system via the autonomic nervous system."

To achieve their goal, the researchers focused on the LHb. Located deep within the brain, the LHb has been known to control behavioral responses to stressful events, and as such to elicit strong cardiovascular responses. However, the way in which it does so has remained unclear. To address this question, the researchers electrically stimulated the LHb in rats by inserting an electrode through the skull. Stimulation of the LHb resulted in bradycardia (low heart rate) and increased mean arterial pressure (MAP), which is a clinically useful parameter for assessing overall blood pressure.

To determine how the LHb interplays with the autonomic nervous system to regulate the cardiovascular system, the researchers then turned off the parasympathetic system by means of cutting the main parasympathetic nerve, the vagal nerve, or using a drug to antagonize it. While this suppressed the LHb's effect on the heart rate, it did not change the MAP. Antagonizing the sympathetic system did the opposite--it decreased the MAP but did not change the heart rate.

To understand the mechanism by which the LHb elicits these cardiovascular responses, the researchers focused on the neurotransmitter serotonin, which plays an important role in the brain in modulating mood, cognition, and memory, among other functions. While blocking all serotonin receptors significantly reduced the LHb's effect on both the MAP and heart rate, the researchers found that specific subtypes of serotonin receptors were particularly involved in the process.

"These are striking results that show how the lateral habenula controls the cardiovascular system. Our results demonstrate the mechanism of a neural circuit that plays an important role in stress-induced behavioral responses," says author of the study Professor Masayuki Matsumoto.

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The article, "Lateral habenula regulates cardiovascular autonomic responses via the serotonergic system in rats" was published in Frontiers in Neuroscience at https://doi.org/10.3389/fnins.2021.655617.

MONOPOLY CAPITALI$M

Lack of competition and transparency: challenges in the online advertising market

In 2019, 98.5% of Google's revenues, and 83.9% of those of Facebook, came from online advertising services

UNIVERSITAT OBERTA DE CATALUNYA (UOC)

Research News

The first online advertisement was a banner for AT&T that appeared on the HotWired.com website in 1994, when there were just 30 million internet users worldwide. Today, 57% of the world's population has access to the internet and advertising technology has advanced to the point that by 2018 the digital advertising market in Europe alone was worth 55 billion euros. Of this amount, 16.8 billion euros is accounted for by programmatic advertising, which uses artificial intelligence to automate much of the buying and selling of internet advertising.

A new report, published by Open Evidence, a spin-off of the UOC, whose authors include Francisco Lupiáñez, a member of the UOC's Faculty of Information and Communication Sciences and a partner and director of Open Evidence, examines the current situation and the challenges for online advertising. The results reveal an online market that is increasingly dominated by just a few companies (e.g., Google, Facebook) which occupy strategic roles throughout the advertising chain, affecting free competition. Among these challenges, the authors point to "the opacity and lack of transparency" in the market and the need to tackle this issue by combining self-regulation in the sector with domestic and international regulatory measures.

The personalization of advertising

The automation of the advertising market has enabled a better fit between supply and demand, allowing digital media publishers to sell advertising space and advertisers to easily reach large audiences on many websites. The system is based on users' data which is collected by browsers and cookies, i.e. small fragments of code that are stored on devices and record information including demographic details and online behaviour, such as the type of website visited and purchases made. This data is sold to advertisers, who can then use it to personalize advertising messages and show them at the best time and place.

This personalization of advertising activity has gone hand-in-hand with the growth of Google and Facebook, which headed the sector in 2017 with 33% and 16.2% of global revenues, respectively. "Both companies, and, to a lesser extent, Amazon, profit greatly from users' data and from providing a vast inventory of advertisements through their websites and services that can be monetized, generating most of their advertising revenues". The researchers note that "83.9% of Facebook's revenues and 98.5% of Google's revenues in 2019 were generated from advertising services".

Potentially anti-competitive practices

The report also states that this market leadership allows Google and Facebook to benefit from economies of scale and network effects, thanks to the interdependence of their services. It also details how a single company can operate "simultaneously as both buyer and seller". Google, for example, is involved on both the demand side for advertising space, through its DV360 campaign manager, and on the supply side, through its AdX exchange platform. At the same time, it also has a key role in support technologies such as website analytics and as a shopwindow for advertisements via its search engine.

All these advantages, argue the researchers, mean these platforms may potentially engage in "anti-competitive practices" such as favouring their own products, using their market power in new sectors, or acting as a barrier to access, by charging higher rates to advertisers, publishers or providers of complementary services, for example.

Technological complexity, opacity and fraud

The report highlights the opacity of the online advertising market as one of the gravest issues among the consequences of this type of practice. This lack of transparency is due "in part to the complexity of programmatic advertising, but also to the practices of the online platforms". Within these platforms, so-called "walled garden" companies like Amazon and Facebook can use their dominant positions to limit the release of information on the cost, revenues and effectiveness of advertising placement. These activities make it "very difficult to know how the money is spent and where the advertisements appear, leading advertisers and publishers to question the effectiveness of the online advertisement and hindering decision-making".

Fraud is another effect of this opacity in the value chain of advertising technology, including dependence on algorithms and the large number of intermediary businesses. According to 2017 figures published in the report, fraud cost advertisers around 13.6 billion euros globally.

International cooperation between regulatory authorities

The study's conclusions also set out a number of solutions to these issues, including responses at public policy level and at the level of the sector and the companies involved. With regard to the issues of competition and transparency, these include measures such as "the creation of units within the regulatory authorities to deal specifically with digital platforms, with control and executive powers; the establishment of codes of conduct; regulatory reforms on disclosure and interoperability, and, if necessary, anti-trust measures". Given the transnational nature of the platforms, the researchers also recommend "cooperation between regulatory authorities to share learning, improve cross-border regulation and coordinate measures".

The report also examines various self-regulatory initiatives within the industry, such as the development of standards and practices for measuring and ensuring the quality of advertisements, guidelines for improving transparency on tariffs and programmes governing users' privacy and consent. Finally, it emphasizes that no measure is sufficient "in itself", but "a better implementation of existing initiatives and a combination of the proposed measures could be effective in tackling the problems identified in this sector".

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This research by the UOC supports Sustainable Development Goal (SDG) 9, Industry, innovation and infrastructure.

UOC R&I

The UOC's research and innovation (R&I) is helping overcome pressing challenges faced by global societies in the 21st century, by studying interactions between technology and human & social sciences with a specific focus on the network society, e-learning and e-health. Over 500 researchers and 51 research groups work among the University's seven faculties and two research centres: the Internet Interdisciplinary Institute (IN3) and the eHealth Center (eHC).

The United Nations' 2030 Agenda for Sustainable Development and open knowledge serve as strategic pillars for the UOC's teaching, research and innovation. More information:research.uoc.edu. #UOC25years

Early Earth's hot mantle may have led to Archean 'water world'

AMERICAN GEOPHYSICAL UNION

Research News

IMAGE: AN ARTIST'S RENDERING OF EARTH DURING THE ARCHEAN EON, WITH A HAZY ATMOSPHERE, FEW LANDMASSES AND A GLOBAL OCEAN. view more
CREDIT: ALEC BRENNER, HARVARD UNIVERSITY

WASHINGTON--A vast global ocean may have covered early Earth during the early Archean eon, 4 to 3.2 billion years ago, a side effect of having a hotter mantle than today, according to new research.

The new findings challenge earlier assumptions that the size of the Earth's global ocean has remained constant over time and offer clues to how its size may have changed throughout geologic time, according to the study's authors.

Most of Earth's surface water exists in the oceans. But there is a second reservoir of water deep in Earth's interior, in the form of hydrogen and oxygen attached to minerals in the mantle.

A new study in AGU Advances, which publishes high-impact, open-access research and commentary across the Earth and space sciences, estimates how much water the mantle potentially could hold today and how much water it could have stored in the past.

The findings suggest that, since early Earth was hotter than it is today, its mantle may have contained less water because mantle minerals hold onto less water at higher temperatures. Assuming that the mantle currently has more than 0.3-0.8 times the mass of the ocean, a larger surface ocean might have existed during the early Archean. At that time, the mantle was about 1,900-3,000 degrees Kelvin (2,960-4,940 degrees Fahrenheit), compared to 1,600-2,600 degrees Kelvin (2,420-4,220 degrees Fahrenheit) today.

If early Earth had a larger ocean than today, that could have altered the composition of the early atmosphere and reduced how much sunlight was reflected back into space, according to the authors. These factors would have affected the climate and the habitat that supported the first life on Earth.

"It's sometimes easy to forget that the deep interior of a planet is actually important to what's going on with the surface," said Rebecca Fischer, a mineral physicist at Harvard University and co-author of the new study. "If the mantle can only hold so much water, it's got to go somewhere else, so what's going on thousands of kilometers below the surface can have pretty big implications."

Earth's sea level has remained fairly constant during the last 541 million years. Sea levels from earlier in Earth's history are more challenging to estimate, however, because little evidence has survived from the Archean eon. Over geologic time, water can move from the surface ocean to the interior through plate tectonics, but the size of that water flux is not well understood. Because of this lack of information, scientists had assumed the global ocean size remained constant over geologic time.

In the new study, co-author Junjie Dong, a mineral physicist at Harvard University, developed a model to estimate the total amount of water that Earth's mantle could potentially store based on its temperature. He incorporated existing data on how much water different mantle minerals can store and considered which of these 23 minerals would have occurred at different depths and times in Earth's past. He and his co-authors then related those storage estimates to the volume of the surface ocean as Earth cooled.

Jun Korenaga, a geophysicist at Yale University who was not involved in the research, said this is the first time scientists have linked mineral physics data on water storage in the mantle to ocean size. "This connection has never been raised in the past," he said.

Dong and Fischer point out that their estimates of the mantle's water storage capacity carry a lot of uncertainty. For example, scientists don't fully understand how much water can be stored in bridgmanite, the main mineral in the mantle.

The new findings shed light on how the global ocean may have changed over time and can help scientists better understand the water cycles on Earth and other planets, which could be valuable for understanding where life can evolve.

"It is definitely useful to know something quantitative about the evolution of the global water budget," said Suzan van der Lee, a seismologist at Northwestern University who did not participate in the study. "I think this is important for nitty-gritty seismologists like myself, who do imaging of current mantle structure and estimate its water content, but it's also important for people hunting for water-bearing exoplanets and asking about the origins of where our water came from."

Dong and Fischer are now using the same approach to calculate how much water may be held inside Mars.

"Today, Mars looks very cold and dry," Dong said. "But a lot of geochemical and geomorphological evidence suggests that early Mars might have contained some water on the surface - and even a small ocean - so there's a lot of interest in understanding the water cycle on Mars."

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AGU (http://www.agu.org) supports 130,000 enthusiasts to experts worldwide in Earth and space sciences. Through broad and inclusive partnerships, we advance discovery and solution science that accelerate knowledge and create solutions that are ethical, unbiased and respectful of communities and their values. Our programs include serving as a scholarly publisher, convening virtual and in-person events and providing career support. We live our values in everything we do, such as our net zero energy renovated building in Washington, D.C. and our Ethics and Equity Center, which fosters a diverse and inclusive geoscience community to ensure responsible conduct.??

Notes for Journalists

This research study will be freely available for 30 days. Download a PDF copy of the paper here. Neither the paper nor this press release is under embargo.

Paper title:

"Constraining the volume of Earth's early oceans with a temperature?dependent mantle water storage capacity model"

Authors:

Junjie Dong, Harvard University, Cambridge, Massachusetts
Rebecca A. Fischer, Harvard University, Cambridge, Massachusetts
Lars P. Stixrude, University of California, Los Angeles, California
Carolina R. Lithgow?Bertelloni, University of California, Los Angeles, California

Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.

Architecture of Eolian successions under icehouse and greenhouse conditions

New study published in Geological Society of America Bulletin

GEOLOGICAL SOCIETY OF AMERICA

Research News

Boulder, Colo., USA: Anthropogenic climate change is one of the foremost scientific and societal challenges. In part, our response to this global challenge requires an enhanced understanding of how the Earth's surface responds to episodes of climatic heating and cooling. As historical records extend back only a few hundred years, we must look back into the ancient rock record to see how the surface of the Earth has responded to shifts between icehouse (presence of ice at the Earth's poles) and greenhouse (no substantial ice at Earth's poles) climates in the past.

In their study published last week in GSA Bulletin, Grace Cosgrove, Luca Colombera, and Nigel Mountney use a novel relational database (the Database of Aeolian Sedimentary Architecture) to quantify the response of ancient eolian systems (i.e., wind-dominated environments, such as sand dune fields) to global climatic shifts between icehouse and greenhouse climates, as registered in the rock record. They analyzed data on thousands of geological features that preserved a record of eolian processes and landforms, from 34 different eolian systems spanning over two billion years of Earth's history.

Their results demonstrate statistically that preserved sedimentary architectures developed under icehouse and greenhouse conditions are fundamentally different. These differences can be tied to contrasting environmental conditions existing on Earth's surface. During icehouse climates, alternations between glacial and interglacial episodes (caused by changes in the Earth's orbit--the so-called Milankovitch cyclicity) resulted in cycles of glacial-episode accumulation and interglacial deflation.

Greenhouse conditions instead promoted the preservation of eolian elements in the geological record due to elevated water tables and the widespread action of biogenic and chemical stabilizing agents, which protected deposits from wind-driven deflation.

In the context of a rapidly changing climate, the results presented in this work can help predict the potential long-term impact of climate change on Earth surface processes.

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Apples to apples: neural network uses orchard data to predict fruit quality after storage

SKOLKOVO INSTITUTE OF SCIENCE AND TECHNOLOGY (SKOLTECH)

Research News

IMAGE: NEURAL NETWORK USES ORCHARD DATA TO PREDICT FRUIT QUALITY AFTER STORAGE. view more
CREDIT: PAVEL ODINEV / SKOLTECH

A researcher from Skoltech and his German colleagues have developed a neural network-based classification algorithm that can use data from an apple orchard to predict how well apples will fare in long-term storage. The paper was published in Computers and Electronics in Agriculture.

Before the fruit and vegetables we all like end up on our tables, they have to be stored for quite some time, and during this time they can develop physiological disorders such as flesh browning or superficial scald (brown or black patches on the skin of the fruit). These disorders contribute to the loss of a substantial amount of product, and a lot of research effort is dedicated to the development of robust methods of disorder prediction - a notoriously difficult task due to the multitude of factors involved, both at the orchard and in the storage facility.

Skoltech Assistant Professor Pavel Osinenko (formerly at Automatic Control and System Dynamics Laboratory, Technische Universität Chemnitz) and his colleagues gathered three years' worth of data on a Braeburn apple orchard in Germany, including weather data and information from non-destructive sensors such as visible and near-infrared spectroscopy. The information gathered included data on chlorophyll, anthocyanins, soluble solids and dry matter content. The team also used assessments of fruit quality post-storage (for instance, consumers like their apples nice and firm, so there is a metric for that).

"The experimental orchard was quite normal and the developed methodology can in fact be implemented in industry without much effort," Osinenko says.

The researchers developed a classification algorithm based on a recurrent neural network and trained it on the orchard data. The algorithm ended up being 80% successful in predicting internal browning of apples, the appearance of cavities on the surface and fruit firmness. "This is definitely a success since we are talking about an automated solution that does not require human experts. Of course, more data and tuning are needed, but as a proof of concept, the achieved results are indeed promising," Osinenko notes.

He adds that thanks to the predictive design of the methodology, farmers can use the information from the classifier to get better yield. And the team has already received inquiries about possible collaboration on other types of fruits and even vegetables since this approach can work for them too.

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Skoltech is a private international university located in Russia. Established in 2011 in collaboration with the Massachusetts Institute of Technology (MIT), Skoltech is cultivating a new generation of leaders in the fields of science, technology and business, is conducting research in breakthrough fields, and is promoting technological innovation with the goal of solving critical problems that face Russia and the world. Skoltech is focusing on six priority areas: data science and artificial intelligence, life sciences, advanced materials and modern design methods, energy efficiency, photonics and quantum technologies, and advanced research. Web: https://www.skoltech.ru/.

Endangered songbird challenging assumptions about evolution

By looking at this newly emerged bird, a University of Colorado Boulder-led research team found an 'evolutionary shortcut' for speciation

UNIVERSITY OF COLORADO AT BOULDER

Research News

Not all species may travel the same path to existence, at least according to new findings from the University of Colorado Boulder and collaborators.

This new research, out now in Science, looked at a newly discovered, endangered songbird located only in South America--the Iberá Seedeater--and found that this bird followed a very rare evolutionary path to come into existence at a much faster pace than the grand majority of species.

By comparing this bird to a closely related neighbor (the Tawny-Bellied Seedeater) in the same group (the southern capuchino seedeaters), the researchers determined that genetic shuffling of existing variations, rather than new random mutations, brought this species into existence--and their own behaviors are keeping them apart.

This species is one of only two known examples across the globe to have traveled this path, challenging the typical assumptions of how new species form.

"One of the aspects of this paper that makes it so cool is that we were able to address this question of how the Iberá Seedeaters formed from multiple different perspectives," said Sheela Turbek, a graduate student in ecology and evolutionary biology (EBIO) at University of Colorado Boulder and the study's lead author.

"Not only did we collect on-the-ground data on who mated with one another and the identity of their offspring, but we also generated genomic data to examine how similar these two species are on a genetic level. We then zoomed out further to look at where the Iberá Seedeater fits in the context of the broader capuchino group."

"Many studies will address one of these aspects or questions but not combine all of these different pieces of information into a single study."

The southern capuchino seedeaters are a group of recently evolved songbirds found throughout South America that is branching rapidly, with many of its species in the early stages of evolution. This family is best known for the dramatic variation with the males in terms of songs and plumage color, while the females are largely indistinguishable even to the most familiar researchers.

The Iberá Seedeater, the most recent member of this family, was first discovered in the remote, swampy grasslands of Iberá National Park in northern Argentina by study co-authors Adrián S. Di Giacomo and Cecilia Kopuchian from Centro de Ecología Aplicada del Litoral, Argentina, in 2001, and then described in scientific literature in 2016.

In that national park, though, are six other closely related species of capuchinos, including the Tawny-Bellied Seedeater, that breed closely beside each other. These species, despite occupying the same environment and eating the same food, rarely interbreed.

And so, researchers wondered why--and how--the Iberá Seedeater even came to be.

They explored these questions in two ways: First, they looked at how this new species may have formed by examining the ways in which its DNA differs from the Tawny-Bellied Seedeater, and second, looking at what mechanisms might be preventing it from interbreeding with the other species that occur in the park.

To do that, Turbek went down to Argentina for the breeding season for three years, staying two and a half to three months at a time, searching for and monitoring nests, collecting blood samples from adults and nestlings, and then, in the final year, performed a behavioral experiment to see whether plumage or song played a roll in terms of species recognition.

"The field work involved in collecting the assortative mating and behavioral data is extraordinarily hard, which is why these kinds of datasets rarely exist. This study and publication are a testament to Sheela's skill and hard work in the field," said Scott Taylor, an assistant professor in EBIO at University of Colorado Boulder, an author on the paper and Turbek's advisor.

What they found is that the two birds are closely related genetically, only distinguishable by the genes involved in plumage coloration. As well, they found that the males responded most aggressively to songs and plumage variations aligning with their own species.

This all means that the species could very well reproduce and hybridize--they just choose not to, therefore reinforcing their own reproductive barriers.

On a broader level, though, when comparing the Iberá Seedeater to other capuchino species, the researchers found that the Iberá Seedeater shares genomic variants with other capuchinos in these regions, but the variants have been shuffled to form a unique combination, which, the researchers argue, could be an evolutionary shortcut that most likely underlies much of the diversity among the different subspecies of this family.

"This is a really beautiful story about a process that we have never seen in quite this way before," says co-author Irby Lovette, director of the Fuller Evolutionary Biology Program at the Cornell Lab of Ornithology.

"The classic and most common evolutionary model for new species is the accumulation of genetic mutations when those species are separated by a geographic barrier over perhaps millions of years. But here we found that genetic shuffling can happen quickly and without geographical isolation. It's almost like 'instant speciation.'"

Leonardo Campagna, a research associate at the Cornell Lab of Ornithology and the senior author on the paper, agrees:

"This is the clearest example in birds of how reshuffling of genetic variation can generate a brand-new species."

The only other organism where this type of evolution has been seen, according to Turbek, is a group of fish found in Africa called the Lake Victoria cichlids.

"It's interesting to see this mechanism operating in something as different as birds," Turbek commented.

While this study focused in part on the role of male behaviors, the researchers are very interested in taking it one step further, examining the role that female choice may also play in reproduction.

"There are many more questions that we have to address," Turbek said.

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Other researchers on the project include Melanie Browne with Centro de Ecologia Aplicada del Litoral in Corrientes, Argentina; Wesley M. Hochachka with the Cornell Lab of Ornithology; Dario A. Lijtmaer and Pablo L. Tubaro with Museo Argentino de Ciencias Naturales Bernardino Rivadavia, Buenos Aires, Argentina; Luis Fabio Silveira with Museu de Zoologia da Universidade de Sao Paulo, Sao Paulo, Brazil; and Rebecca J. Safran with CU Boulder.

Floating gardens as a way to keep farming despite climate change

Bangladesh's historic farming systems could offer a way forward

OHIO STATE UNIVERSITY

Research News

COLUMBUS, Ohio - Bangladesh's floating gardens, built to grow food during flood seasons, could offer a sustainable solution for parts of the world prone to flooding because of climate change, a new study has found.

The study, published recently in the Journal of Agriculture, Food and Environment, suggests that floating gardens might not only help reduce food insecurity, but could also provide income for rural households in flood-prone parts of Bangladesh.

"We are focused here on adaptive change for people who are victims of climate change, but who did not cause climate change," said Craig Jenkins, a co-author of the study and academy professor emeritus of sociology at The Ohio State University. "There's no ambiguity about it: Bangladesh didn't cause the carbon problem, and yet it is already experiencing the effects of climate change."

Bangladesh's floating gardens began hundreds of years ago. The gardens are made from native plants that float in the rivers - traditionally, water hyacinths - and operate almost like rafts, rising and falling with the waters. Historically, they were used to continue growing food during rainy seasons when rivers filled with water.

The farmers - or their families - layer the plants about three feet deep, creating a version of raised-bed gardens that float in the water. Then, they plant vegetables inside those rafts. As the raft-plants decompose, they release nutrients, which help feed the vegetable plants. Those vegetable plants typically include okra, some gourds, spinach and eggplant. Sometimes, they also include spices like turmeric and ginger.

Floating gardens are also in use in parts of Myanmar, Cambodia and India. The United Nations Food and Agricultural Organization has named Bangladesh's floating gardens a Globally Important Agricultural Heritage System.

But as climate change has affected the volume of water in those rivers - creating extreme highs and floods, along with extreme lows and droughts - floating gardens have become a way for rural farmers to keep producing food during unpredictable weather. Climate change increases weather extremes and the severity of flooding, and droughts as well.

The researchers wanted to understand whether Bangladesh's floating gardens could be a sustainable farming practice as climate change continues to cause floods and droughts, and to see whether the gardens bring better food security to individual households.

"They've got to be able to grow specific crops that can survive with minimal soil," said Jenkins, who is also a research scientist and former director of the Ohio State Mershon Center for International Security Studies. "And in Bangladesh, a lot of small farmers that had typically relied on rice crops are moving away from those because of the effects of climate change and better returns from alternative crops."

For this study, the researchers interviewed farming families who use floating gardens, and found strong evidence that floating gardens provide stability, both in the amount of food available to feed rural populations and in a farming family's income, despite the instability created by a changing climate.

They found that farmers typically use hybrid seeds, which must be repurchased each year, to grow a diverse range of vegetables in the floating gardens. The gardens are also susceptible to pests, so farmers end up spending some money on both pesticides and fertilizers. But even with those expenses, they found, benefits outweighed costs.

Generally, entire families work on the gardens, the researchers found: Women, children and the elderly prepare seedlings and collect aquatic plants to build gardens. Men cultivate the gardens and protect them from raiders. Some families also farm fish in the waters around their floating gardens.

One farmer told the research team that he earns up to four times as much money from the gardens as from traditional rice paddies.

Still, the system could use improvements, the researchers found. Farmers often take out high-interest loans to cover the investment costs of building the beds and stocking them with plants. Lower-interest loans from responsible government or non-governmental organizations could alleviate that burden, they found.

Coastal lupine faces specific extinction threat from climate change

WASHINGTON UNIVERSITY IN ST. LOUIS

Research News

IMAGE: CLIMATE CHANGE REPRESENTS A SPECIFIC EXTINCTION THREAT FOR AN ENDANGERED COASTAL LUPINE PLANT KNOWN AS TIDESTROM'S LUPINE (LUPINUS TIDESTROMII), FOUND AT THE POINT REYES NATIONAL SEASHORE, CALIFORNIA, UNITED STATES. view more
CREDIT: ELEANOR PARDINI, WASHINGTON UNIVERSITY IN ST. LOUIS

Climate change is altering the world we share with all living things. But it's surprisingly difficult to single out climate change as an extinction threat for any one particular species protected under the Endangered Species Act.

To date, the U.S. Fish and Wildlife Service has only formally considered impacts from climate change in listing actions for four animal species and one alpine tree.

But the effects of climate change extend to temperate climates as well. A new analysis of population data published in the journal Ecosphere shows that climate change represents a specific extinction threat for an endangered coastal lupine plant.

Biologists including Eleanor Pardini at Washington University in St. Louis have tracked all of the known stands of Tidestrom's lupine, Lupinus tidestromii, at Point Reyes National Seashore north of San Francisco for more than 14 years.

If average temperatures increase by one degree Celsius (1° C, or about 1.8 degrees Fahrenheit) -- a conservative assumption -- the scientists project that 90% of individual lupine plants could be lost in the next 30 years.

"In general, it is fairly difficult to conclusively say that climate change is a species threat," said Pardini, assistant director of environmental studies at Washington University and senior lecturer in Arts & Sciences.

Modeling the threat of climate change requires long-term population data, which is difficult to collect and thus not available for most species.

"We were able to perform this analysis and show climate change is an important additional threat factor for this species because we have spent considerable effort collecting a long-term dataset," Pardini said.

An overlooked threat

To date, regulators have considered climate change in their listing actions only for four animal species: the polar bear, American pika, American wolverine and Gunnison sage-grouse.

Tidestrom's lupine is different, and not just because it's a plant. It's from a more seasonally mild coastal area -- not someplace that one might think would be rocked by a few degrees of rising temperatures. The animals that have been previously considered all occur in arctic, alpine or arid regions.

"While our results on L. tidestromii could be an isolated case, they suggest that the extinction threat posed by climate change might be overlooked in temperate biomes," Pardini said.

The delicate, purple-flowering lupine is part of a dune ecosystem along the west coast of the United States that is highly disturbed. In many of these coastal places, people have planted exotic plants to be able to develop and farm closer to the beach. Over time, exotic plants have over-stabilized dunes, disrupting wind and sand movement and harming plants and animals.

For the new study, Pardini worked with Tiffany Knight and Aldo Compagnoni, both of Martin Luther University Halle-Wittenberg and the German Centre for Integrative Biodiversity Research (iDiv) in Germany. Pardini and Knight have been tracking populations of Tidestrom's lupine at Point Reyes since 2005. Compagnoni joined the team as an expert in demographic modeling incorporating climate data.

The scientists produced population trajectories for all populations of the species at Point Reyes for the next 30 years.

"Using 14 years of demographic data from 2005 to 2018 and model selection, we found that survival and fertility measures responded negatively to temperature anomalies," said Compagnoni, first author of the new study. "We then produced forecasts based on stochastic individual-based population models that account for uncertainty in demographic outcomes."

If temperatures remain at the 1990-2018 average levels, the scientists expect that the number of individual lupine plants would double over the next 30 years. However, with a 1° C increase in temperature, the number of plants will instead drop off dramatically, with an expected 90% reduction in the number of individual plants.

This scenario is conservative, as even more dramatic increases in temperature than 1° C are projected for this region of California in the next 30 years.

"Despite large uncertainties, we predict that all populations will decline if temperatures increase by 1° Celsius," Compagnoni said. "Considering the total number of individuals across all seven populations, the most likely outcome is a population decline of 90%. Moreover, we predict local extinction is certain for one of our seven populations."

"Our species has a range so small that its response to climate cannot be inferred from its geographic distribution," Pardini said. "In these cases, long-term data collection becomes an important alternative option to assess the climatic vulnerability of a species."

Some rare species that are endemic to coastal habitats are currently protected by the Endangered Species Act and by various state listings.

Many Tidestrom's lupine populations are protected against development because they occur in a national park or state parks. However, Knight expressed general concern about the proposed new regulations that would allow coastal habitats to be excluded in the future because they are economically valuable to developers. Coastal plant communities provide a wide variety of valuable ecosystem services, such as mitigating the effects of coastal erosion and flooding.

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Thursday, April 01, 2021

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Endangered songbird challenging assumptions about evolution

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