Cold weather cost New England electric customers nearly $1.8 billion in one month; A new study suggests ways to mitigate fuel shortages

CARNEGIE MELLON UNIVERSITY

Research News

 

In New England, constraints in the supply of natural gas have led to nearly a quarter of all unscheduled power plant outages. In a new study, researchers used data from power plant failures in the 2010s to develop a supply curve of the costs required for generators to mitigate fuel shortages in the region. The study found that storing both oil and gas on-site could reduce dependence by power plants on gas grids in geographic areas with few pipelines.

The study was conducted by researchers at Carnegie Mellon University (CMU), The Pennsylvania State University, and the North American Electric Reliability Corporation. It is published in The Electricity Journal.

"Gas supply issues have affected the ability to generate electricity during times of high demand," says Jay Apt, Professor at CMU's Tepper School of Business and Department of Engineering and Public Policy, who co-authored the study. "For example, it's estimated that the extended cold weather event in January 2014 cost New England electricity ratepayers roughly $1.8 billion."

New England has no native gas production, so fuel assurance for natural gas power plants is an area of concern; half of all installed power plant capacity in the region is fueled primarily by gas and nearly half of all electricity comes from natural gas power plants. When heating demand spikes on key gas supply pipelines to the region, those pipelines cannot always meet all the region's heating demand and demand for power-plant fuel at the same time.

The effect of gas supply constraints on Northeastern power generators can be seen by comparing the average fraction of total unscheduled generator outages due to gas fuel unavailability to those during days of high demand for heating. In recent periods of high electricity and gas demand, unscheduled gas shortages accounted for 5 to 25 percent of all unscheduled generator outages during every hour of those periods.

Dual fuel capability--that is, the ability to burn either oil or gas--is one way to mitigate gas supply shortages, and about a third of ISO New England's natural gas power plant capacity has dual fuel capability (ISO New England is an independent, not-for-profit corporation that manages the high-voltage power system over six New England states). But building dual fuel storage tanks for the remainder has been considered prohibitively expensive.

In 2019, one of the study's coauthors--Seth Blumsack, Professor of Energy Policy and Economics at The Pennsylvania State University--developed a model to identify where to build distributed gas storage capability in New England. To increase reliability of the interdependent gas and electricity grids, Blumsack and his students identified economically optimal sites for distributed gas storage in the region. They concluded that power plant sites might be the optimal locations for gas storage.

In this study, researchers analyzed a database of historical power plant failures, using data from the North American Electric Reliability Corporation--NERC--a not-for-profit international reliability organization. They determined what the cost of on-site fuel storage at natural gas power plants would have to be to mitigate the worst gas shortages in New England during the seven years studied.

The study assessed 54 gas-fired units operating within ISO New England that had NERC reports of full or partial outages due to unscheduled fuel shortages between 2012 and 2018. For each unit, researchers calculated the overnight capital, fuel carrying, and land costs (when applicable) required for gas generators in the region to assure that fuel supplies using fuel storage systems were sized according to their most extreme fuel shortage failure during the study period. They also examined distributed compressed natural gas storage at generator sites and dual fuel capabilities with oil storage. The researchers compared these costs to those of installing batteries with enough capacity to cover historically observed fuel outages.

The researchers found that approximately 2.4 gigawatts (GW) of ISO New England's gas-fired capacity failed one or more times per year due to fuel shortages; up to 0.5 GW of these units failed simultaneously on three separate occasions. Of these, approximately 2 GW of gas-fired capacity could be mitigated by on-site fuel storage. Furthermore, gas plants would recoup their investment in oil backup fuel if they were compensated with an additional $3 to $7 per megawatt-hour (MWh) during their normal operations.

Using on-site compressed natural gas storage is more expensive ($7 to $16/MWh). The capital expenses associated with either on-site fuel storage option would be less than installing battery backup for resource adequacy at current battery prices, the study concluded.

"Our estimates differ from previous studies because they are based on actual failure events rather than arbitrary fuel supply durations," explains Gerad Freeman, an Energy Systems Research Engineer at Pacific Northwest National Laboratory, the study's lead author. "As such, they have implications for moving forward on increasing dual fuel capacity to increase the resilience of power systems in New England and other regions with similar gas supply constraints."

The authors note that limitations to this research include that they may oversize the dual fuel storage by basing fuel storage tank sizes on the longest observed gas outage at each unit, that batteries can receive some revenue by providing grid services during non-emergencies, and that compressed natural gas storage might help balance gas supply and demand.

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The study was funded in part by the Carnegie Mellon Climate and Energy Decision Making Center, formed through a cooperative agreement between the National Science Foundation and CMU, and in part by the Electric Power Research Institute.

 

NASA helps map impact of COVID-19 lockdowns on harmful air pollution

NASA/GODDARD SPACE FLIGHT CENTER

Research News

 

IMAGE: CHANGES IN PM 2.5 CONCENTRATIONS OVER CHINA FOR FEBRUARY 2019 AND 2020 DERIVED FROM SATELLITE OBSERVATIONS. view more 

CREDIT: NASA'S EARTH OBSERVATORY

Early in the pandemic, it was expected that satellite imagery around the world would show cleaner air as a result of COVID-19 lockdowns. But not all pollutants were taken out of circulation. For tiny airborne-particle pollution, known as PM 2.5, researchers using NASA data found that variability from meteorology obscured the lockdown signals when observed from space.

"Intuitively you would think if there is a major lockdown situation, that we would see dramatic changes, but we didn't," said Melanie Hammer, a visiting research associate at Washington University in St. Louis who led the study. "It was kind of a surprise that the effects on PM 2.5 were modest."

PM 2.5 describes the mass of nose-level particles, often produced anthropogenically, that are smaller than 2.5 micrometers, or roughly 30 times smaller than the width of a human hair. PM 2.5 is small enough to linger in the atmosphere, and, when inhaled, is associated with increased risk of heart attack, cancer and a host of other implications for human health.

By combining NASA spacecraft data with ground-based monitoring and an innovative computer modeling system, the scientists mapped PM 2.5 levels across China, Europe and North America during the early months of the pandemic. The researchers found seasonal differences in PM 2.5 between recent years were driven primarily by the natural variability of the meteorology, not by pandemic lockdowns.

Published June 23 in the journal Science Advances, the new research integrates data from NASA's Terra and Aqua satellites, as well as meteorological modeling input from the NASA Global Modeling and Assimilation Office.

The meteorological effects analyzed in the study include changes in the sources of mineral dust, the way pollutants react to sunlight in the atmosphere, mixing and heat transfer, as well as the removal of pollutants from the atmosphere by precipitation.

PM 2.5 is among the most complicated pollutants to study because its particle size, composition and toxicity vary greatly depending on its source and environmental conditions.

A gas pollutant known as nitrogen dioxide, or NO2, did see dramatic declines during the lockdowns. A major byproduct of fuel burning by trucks, cars and other vehicles, the decline of nitrogen dioxide was visible from space and from the ground. Images of clear, blue skies where heavy smog had been the norm flooded popular news and social media, suggesting COVID-19 has drastically decreased all pollution in general.

When nitrogen dioxide is emitted, it can also interact with other chemicals in the atmosphere and form PM 2.5. However, the two pollutants do not have a linear relationship. Half as much nitrogen dioxide in the atmosphere does not necessarily lead to half as much PM 2.5 produced by nitrogen dioxide.

Because PM 2.5 often comes from the same sources as NO2, the researchers also began to question whether the lockdowns resulted in a decline of PM 2.5.

Early pandemic studies of PM 2.5 changes analyzed data from ground monitoring sites, which test the surrounding air. But because those ground sites are few and far between, their data alone are unable to piece together the bigger picture of PM 2.5 concentrations in the air, Hammer said.

"We were most interested in looking at changes in PM 2.5 because PM 2.5 is the leading environmental risk factor for premature mortality globally," Hammer said. "We decided to look again, using a more complete picture from satellite images."

The study was co-led by Randall Martin at Washington University in St. Louis, who pioneered research integrating modeling and remote sensing to study atmospheric pollutants such as PM 2.5.

"Many countries in the world have no operational PM 2.5 monitoring at all," Martin said. "These tools enable insight into ground level PM 2.5 at the global or regional scale."

To ensure a comprehensive analysis, the team focused on regions with extensive ground monitoring systems in place and compared monthly estimates of PM 2.5 from January to April in 2018, 2019 and 2020.

When the researchers compared PM 2.5 levels over the three years during the months that coincided with each region's lockdown phases, there weren't many clear signals over North America or Europe. The most significant lockdown-related differences were detected in China.

"We found the most clearly detectable signal was a significant reduction over the North China Plain, where the strictest lockdowns were concentrated," Hammer said.

To figure out whether the lockdown was responsible for that signal, and several smaller ones dotted around the areas surveyed, the team ran different "sensitivity simulations" using GEOS-Chem, a chemical transport model to which Martin's team helps lead.

CAPTION

Changes in simulated PM 2.5 in China during the lockdown periods due to meteorology and emissions. The image on the left shows 2020-2019 concentrations due to meteorology with emissions from transportation held constant. The image on the right combines the effects of meteorology with a 50% transportation emission reduction.

CREDIT

NASA's Earth Observatory

They simulated a scenario where anthropogenic emissions of nitrogen dioxide were held constant and meteorological variability was solely responsible for year over year differences in PM 2.5 during the key lockdown months. They also ran simulations in which they reduced transportation-related emissions and other anthropogenic sources of nitrogen dioxide, mirroring lockdown, when fewer people were driving and fewer industrial sites were operational.

They found the simulation where both meteorology and transportation effects were included most closely mirrored the real-world situation.

"Tackling PM 2.5 is a very complex issue, and you have to take into account its multiple sources, not just the fact that fewer people are on the road," Hammer said. "Just decreasing transportation emissions would not be enough to account for the complexity of the problem."

Most satellites sample the atmosphere through vertical columns spanning the ground to the edge of space. Identifying the concentrations of airborne particles near the surface, where they affect air quality, cannot be determined from these satellites alone.

The satellite data used in this study, referred to as aerosol optical depth, were related to surface PM 2.5 concentrations using GEOS-Chem, which simulates the composition of the atmosphere, the reactions and relationships among its different components, and the way they move horizontally as well as vertically through the air.

The model is a sophisticated tool that helps paint a more complete picture of air quality, said Ralph A. Kahn, senior research scientist at NASA's Goddard Space Flight Center in Greenbelt, Maryland and adjunct professor at University of Maryland in College Park.

"The bigger story is actually the global characterization of air quality, especially in places where there aren't surface monitors," said Kahn, who was part of the study. "The satellites provide an important piece of it, the models provide an important piece of it, and the ground-based measurements make an important contribution as well."

Hammer suspects the change in PM 2.5 levels over the North China Plain was more apparent because of the region's higher pollution levels during "normal" times.

The new insights also highlight a relevant point that may not at first be intuitive: Average PM 2.5 levels have been dropping steadily in North America and Europe. Pollution concentrations that are already low are more difficult to change, Hammer said.

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By Brandie Jefferson
Washington University in St. Louis

Media Contact: Roberto Molar Candanosa, NASA's Earth Science News Team

Coral offspring physiology impacted by parental exposure to intense environmental stresses

Environmental disturbances, such as bleaching events, can have lasting consequences across generations of corals

BERMUDA INSTITUTE OF OCEAN SCIENCES

Research News

IMAGE: A RECENT PUBLICATION IN THE JOURNAL GLOBAL CHANGE BIOLOGY DOCUMENTS THE RESULTS OF TWO YEARS OF EXPERIMENTS CONDUCTED AT BIOS BY A TEAM OF RESEARCHERS INCLUDING KEVIN WONG (SHOWN HERE),... view more 

CREDIT: KEVIN WONG

Adult corals that survive high-intensity environmental stresses, such as bleaching events, can produce offspring that are better suited to survive in new environments. These results from a series of experiments conducted at the Bermuda Institute of Ocean Sciences (BIOS) in 2017 and 2018 are deepening scientists' understanding of how the gradual increase of sea surface temperatures and other environmental disturbances may influence future coral generations.

Researchers on the project included BIOS marine ecologists Samantha de Putron and Gretchen Goodbody-Gringley (now with the Central Caribbean Marine Institute), ecophysiologist Hollie Putnam at the University of Rhode Island (URI), and Kevin Wong, then a first-year doctoral student at URI. Primary funding came from the Heising-Simons Foundation International, Ltd. with additional funding from the National Geographic Society and the Canadian Associates of BIOS (CABIOS).

The team spent last year working the data into a manuscript, which was published this month in the journal Global Change Biology and listed Wong as the first author. Wong, now nearing the end of his fourth year of studies at URI under the mentorship of Putnam, plans to graduate in May 2022.

"We know parental history influences the characteristics of offspring in corals, however the experimental design used in this study provides us with a unique perspective on how multiple types of thermal events can accumulate over time and have lasting consequences across generations," Wong said.

Coral Collection and Study The multi-year field and lab-based study began in the summer of 2017. Departing from BIOS on a small boat with diving gear, the team collected 40 adult Porites astreoides (mustard hill) corals from two different reef sites northwest of Bermuda: a patch reef (Crescent Reef), which is located in a shallower lagoon environment, and a rim reef (Hog Reef) which is a barrier reef more exposed to open ocean conditions.

They next placed the live corals in the then newly-constructed BIOS mesocosm facility, where large outdoor aquaria "flow-through" seawater systems allowed researchers to control and adjust water temperature in the tanks for completing the study.

A variety of baseline data were collected on the corals in each colony, such as metabolic rates and the density of Symbiodinaceae, the symbiotic algae that live within the coral tissues. To simulate a thermal stress event, the adult corals were exposed to two different temperature treatments--ambient (84°F or 29°C) or heated (88°F or 31°C)--for a period of 21 days over their reproductive period. Afterward, the team assessed the physiology of the adult corals, looking at key functions such as respiration and photosynthetic rates. They also monitored the release of coral larvae and assessed its physiology, measuring the larval size and density of Symbiodinaceae within each larva, among other factors.

Upon completion of the experiment, the adult corals were divided in half and reciprocally transplanted, with half of the fragments positioned in the new environments and half returned to their originating environments. All of the fragments remained in place until the summer of 2018, when they were re-collected, and the physiologies of both adult corals and coral larvae were assessed in the same manner as in 2017.

A Stronger Coral Generation The results of this two-year investigation showed that adult corals that experienced the thermal stress event produced offspring more capable of thriving in their current environment. This means that parent corals that experience stressors may be able to "pre-condition" their offspring to survive in new environments in the following year. The results also indicate that high-intensity environmental stress events, such as bleaching, can have lasting impacts on adult colonies and how they produce their offspring.

"The coral used in this study is a notoriously resilient coral and these findings potentially demonstrate how this species is so persistent across the Caribbean," Putnam said. "Not all coral species are this robust to environmental stressors. However, this system allows us to unravel the mechanisms leading to resilience and identify which corals are most sensitive to climate change."

CAPTION

The team of researchers, which included BIOS marine ecologists Samantha de Putron and Gretchen Goodbody-Gringley (now with the Central Caribbean Marine Institute) and ecophysiologist Hollie Putnam (URI), utilized the outdoor mesocosm facility at BIOS to study the impacts of a simulated thermal stress event on adult corals collected from two different reef sites northwest of Bermuda. The results of the study showed that parent corals that experience stressors may be able to "pre-condition" their offspring to survive in new environments in the following year.

CREDIT

Rebecca Ju

Long-time Member of BIOS Community Wong, 27, is a familiar face at BIOS, having first arrived on campus in the summer of 2014 as a CABIOS intern when he spent 12 weeks working with de Putron on a research project investigating the role of temperature and light on the growth and survivorship of juvenile mustard hill corals from two different reef zones. The following year, he received CABIOS funding to work with then-faculty member Gretchen Goodbody-Gringley on a project focused on the reproductive ecology of corals from mesophotic reef ecosystems, deeper-water reefs which typically extend from 100 to almost 500 feet (30 to 150 meters) in depth.

While presenting the results of his research at the 2016 International Coral Reef Symposium meeting in Hawaii, he had the opportunity to interview with Putnam for URI's Biological and Environmental Sciences doctoral program. Wong then returned to BIOS to spend six months in 2016 as a teaching assistant for several summer and fall courses. He also received BIOS Grants-in-Aid funding for a research project with Goodbody-Gringley and de Putron focused on the reproductive ecology of mustard hill coral from various reef sites around Bermuda, resulting in a publication in the journal Coral Reefs.

"It is wonderful to see an undergraduate intern progress to a successful graduate student who is publishing manuscripts," de Putron said. "Many years of hard work and plenty of exhausting, yet fun, days in the field and laboratory all culminated in interesting and critically relevant discoveries that further our understanding of coral resilience."

Now, a year from graduation, Wong is diving deeper into the mechanisms that drive environmental memory within and across coral generations at a molecular level. By using approaches such as metabolomics (the identification and quantification of metabolic by-products), transcriptomics (quantification of gene expression), and epigenetics (features that regulate gene expression), Wong aims to determine the key linkages between metabolism and coral bleaching phenotypes at a cellular level.

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PSU study finds chemicals from human activities in transplanted oysters far from population centers

PORTLAND STATE UNIVERSITY

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IMAGE: AMY EHRHART CHECKING TRANSPLANTED OYSTERS ALONG THE PACIFIC COAST. view more 

CREDIT: ELISE GRANEK

Wastewater treatment facilities clean the water that goes down our sinks and flushes our toilets, but they do not remove everything. A recent study by Portland State researchers detected low levels of pharmaceuticals and personal care product chemicals in oysters the team deployed at various distances from wastewater effluent pipes along the Oregon and Washington coast. Elise Granek, professor of environmental science and management at Portland State University, and Amy Ehrhart, a recent graduate of PSU's Earth, Environment, and Society doctoral program, conducted the study.

To explore how aquatic pollution varies based on proximity to wastewater facilities, Ehrhart and Granek placed one-week-old Pacific oysters at wastewater sites (not approved by state agencies as oyster growing sites) and near oyster aquaculture sites (approved for growing oysters) along the Oregon and Washington coastline. Nine and twelve months later, they collected the oysters, measured their health and size, and tested their tissues for pharmaceuticals and chemicals called alkylphenols, which are used in a variety of personal care and industrial products. Alkylphenols are endocrine disruptors that can alter the growth and reproduction of aquatic organisms.

Out of the 63 compounds tested, Granek and Ehrhart found only six in the oysters. The two pharmaceuticals detected in the oysters were miconazole, an over-the-counter drug for fungal infections like Athlete's foot, and virginiamycin, a veterinary antibiotic used in livestock. As expected, the concentrations of pharmaceuticals were higher near the wastewater sites. The condition of the oysters was also poorer at wastewater sites compared to the sites near oyster farms.

Four types of alkylphenols were found in oysters from all the sites.

"This makes sense because they are really ubiquitous," said Ehrhart. "They're found in all sorts of common household and industrial products."

Everyday products like detergents, cosmetics, soaps, and cleaners often contain alkylphenols as do forestry pesticide application mixtures. While detectable, the chemical levels were much lower than reported in other estuarine studies near more populated areas.

"The levels that we found were very low," Ehrhart said. She noted that the levels detected are significantly lower than the Environmental Protection Agency's no effect level for nonylphenol exposure in humans and the Food and Drug Administration's allowable limits for antibiotics in meat. "It's unlikely to pose a risk to human consumers of shellfish," she said. Additionally, the Oregon Department of Agriculture and Washington Department of Health continually monitor and approve areas for shellfish growing to ensure they meet strict water quality standards for food safety.

That said, the very presence of these chemicals in oysters relatively far from wastewater sites and in sparsely populated coastal areas suggests that current wastewater treatment technology, stormwater mitigation strategies, and industrial use guidelines for alkylphenol use may not be sufficient. This could be bad news for aquatic animals, including shellfish.

"It's not an aquaculture-driven problem. It's coming from upstream, but it's making its way to aquaculture and it may be negatively affecting oysters, given other studies on how alkylphenols can affect animals," says Granek. "So it really points to a need to address the sources of these alkylphenols."

Granek suggested that possible solutions for this kind of aquatic pollution include upgrading wastewater treatment plants and creating regulations that target the use of industrial products containing alkylphenols.

Individuals can also do their part by not flushing medications down sinks or toilets and instead using drop boxes available at many pharmacies.

"For the pharmaceuticals it's better disposal, for the alkylphenols it's buying products that don't have them," said Ehrhart.

It can be difficult to determine which products contain alkylphenols just from reading ingredient lists, so Ehrhart suggests looking for the EPA's Safer Choice label. "If you see that on cleaning products and detergents, that means that those products don't have alkylphenols, so they are better for the environment."

The study was published in Marine Pollution Bulletin on June 20.

CAPTION

Amy Ehrhart conducting research with transplanted oysters along the Pacific coast.

CREDIT

Elise Granek

 

Influence of land use on soil erosion in European Russia for the last 30 years

A comprehensive study of this large region of Russia saw light in Water

KAZAN FEDERAL UNIVERSITY

Research News

 

IMAGE: CHANGE IN THE TOTAL AREA OF CULTIVATED LAND (F) IN THE RUSSIAN FEDERATION IN 1970-2017. RSFSR--THE RUSSIAN SOVIET FEDERATIVE SOCIALIST REPUBLIC AS THE PRINCIPAL PART OF THE FORMER USSR UNTIL... view more 

CREDIT: KAZAN FEDERAL UNIVERSITY

Research Associate Artyom Gusarov studied a vast array of erosion data to make a general takeaway that soil erosion and river sediment load in the aforementioned region has significantly decreased throughout the post-Soviet period.

"The decrease has been especially profound in the forest steppe, a part of which covers the Republic of Tatarstan, because of the combined influence of climate change and land cultivation," explains Gusarov. "To the north of the forest steppe, in the southern part of the boreal zone, the anthropogenic factor was the primary influence on the changes in soil erosion, at least in the east of the East European Plain. Here, the reduction of cultivated land was the biggest in the post-Soviet time. In the steppes, the primary role can be attributed to climate change, especially the warming of the near-soil air, which led to decreased frosting of soils during winters, and, therefore, decreased erosion-inducing sediment from tillage."

The research shows that there is a complex intertwining between seemingly negative socio-economic developments and environmental conditions.

"The recession of agriculture in contemporary Russia, including decreases in tillage areas, numbers of agricultural machines, livestock population, etc., led to decreased soil and ravine erosion in the region, decreased river sediment load and concomitant pollution," says Gusarov.

The results are very important for the comprehensive planning of soil preservation, hydrogeological construction, and artificial water bodies. Artyom Gusarov aims to continue this research, now moving to the northern part of the East European Plain and the rivers running into the Arctic Ocean.

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Asian elephants do more than just trumpet -- they buzz their lips to squeak

The animals' sound production does not only come from the trunk

UNIVERSITY OF VIENNA

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IMAGE: WITH THE ACOUSTIC CAMERA´S STAR-SHAPED ARRAY OF MICROPHONES PLACED IN FRONT OF THE ELEPHANT THE RESEARCHERS ARE WAITING PATIENTLY FOR HER TO VOCALIZE WHILE NIGHT FALLS. view more 

CREDIT: © GUNNAR HEILMANN

Everybody from a child knows that elephants trumpet. Over the past decades research in general and at the University of Vienna has mainly studied the elephants low-frequency rumble. Its fundamental frequency reaches into the infrasonic range below the human hearing threshold. This call is produced by the elephant´s massive vocal folds. Much less was known about how elephants produce their higher pitched sounds, trumpets and squeaks.

The following rule generally applies to sound production in mammals: the larger the vocal fold, the lower the calls fundamental frequency. Conversely the size of the vocal folds sets an upper limit to the fundamental frequencies that can be reached. The high-pitched squeak only Asian but not African elephants produce when aroused, do not fit within that spectrum.

In her recent study Veronika Beeck, who is part of the FWF doctorate school Cognition and Communication at the Department of Behavioural and Cognitive Biology at the University of Vienna and her supervisor Angela Stöger, together with Gunnar Heilmann and Micheal Kerscher from gfai tech, Berlin, studied the squeak sounds of Asian elephants in Nepal.

The researchers used an acoustic camera with an array of 48 microphones that visualises sounds in colours similar to a thermic camera. In this way the sound source was precisely located. "Our images clearly demonstrate that the squeaks are emitted by the mouth and not the trunk", Veronika Beeck explains.

According to the researcher's theory the Asian elephants produce squeaks by pressing air through their tensed lips inducing the lip´s vibration. This technique equals the human brass players lip buzzing to produce a complex sound whose harmonic overtones are subsequently resonated by the instrument, resulting in its characteristic brassy sound. "Apart from human brass players this technique of lip buzzing to produce sounds has, to our knowledge, not been described in any other animal species and is thus considered unique in the animal kingdom", says Veronika Beeck.

The elephants iconic trumpet on the other hand is produced by a blast of air through the trunk. Here again, however, the vibrating anatomic sound source is not yet conclusively studied.

This new evidence further highlights the elephant´s flexibility in sound production. A few years ago, Angela Stöger-Horwath showed that elephants are capable of learning novel sounds. An Asian elephant in a Korean Zoo, by imitating his trainer, learned to speak some words in Korean. Since only a few elephants in this recent study squeaked the researchers suggest that squeaks might be learned, too.

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Publication in BMC Biology:
A novel theory of Asian elephant high-frequency squeak production.
Veronika C. Beeck, Gunnar Heilmann, Michael Kerscher, Angela S. Stoeger
DOI: BMCB-D-20-01049

 

The origins of farming insects

Ambrosia fungi cultivated by beetles for more than 100 million years

UNIVERSITY OF BARCELONA

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IMAGE: THE AMBROSIA BEETLE CROSSOTERASUS EXTERNEDENTATUS (CURCULIONIDAE: PLATYPODINAE). view more 

CREDIT: BJARTE JORDAL, UNIVERSITY OF BERGEN (NORWAY)

A beetle bores a tree trunk to build a gallery in the wood in order to protect its lay. As it digs the tunnel, it spreads ambrosia fungal spores that will feed the larvae. When these bore another tree, the adult beetles will be the transmission vectors of the fungal spores in another habitat. This mutualism among insects and ambrosia fungi could be more than 100 years old --more than what was thought to date-- according to an article published in the journal Biological Reviews.

The study analyses for the first time the symbiotic associations and the coevolution between ambrosia fungi and beetles from a paleontological perspective using the Cretaceous fossil records of these biological groups. Among the authors of the study are the experts David Peris and Xavier Delclòs, from the Faculty of Earth Sciences and the Biodiversity Research Institute of the University of Barcelona (IRBio), and Bjarte Jordal, from the University of Bergen (Norway).

Beetles that grew fungi millions of years before human agriculture

Some termites, ants and beetles developed the ability to grow fungi in order to eat millions of years ago. This mutualism between insects and fungi --one of the top studied symbiosis in the natural field-- is an analogous evolutionary strategy in the farming activities of the human species since the Neolithic revolution.

Understanding the origins of the symbiosis between insects and fungi is a field of interest in several scientific disciplines. Nowadays, the mutualism between ambrosia symbiont beetles and fungi is the cause of forest and crop plagues that cause serious ecological and economic losses "it remains unclear which ecological factors facilitated the origin of fungus farming and how it transformed into a symbiotic relationship with obligate dependency", notes David Peris, first author of the study.

When did the lineage of farming insects begin?

Historically, phylogenetic studies suggest beetle fungiculture started more than 50 million years ago --before other insects-- and some studies dated it back to 86 million years ago. "The symbiotic relationship between fungus and beetles would have probably originated more than 100 million years ago, during the early Cretaceous, in groups of beetles that had gone unnoticed", reveals the expert David Peris.

As part of the study, the experts studied several specimens of worldwide distribution of the biological groups captured in amber from the Cretaceous. Therefore, the origin of ambrosia fungus is older than the main groups of beetles from the subfamilies Scolytinae and Platypodinae --Curculionidae family-- which now grow fungus in tree trunks, as stated by the authors.

"This suggests that these fungi used some other group of insects to spread millions of years ago", notes the researcher. Also, other beetle groups with a similar behaviour to ambrosia beetles --Bostrichidae and mostly Lymexylidae families-- present an older and abundant fossil record that would coincide with the emergence of ambrosia fungi, according to previous studies.

"The most interesting thing --he continues-- is that some studies note the ability to cultivate fungi in some of these current species".

Evolutionary convergence towards an obligate mutualism

The growing process of fungi starts when beetles colonize a new tree trunk or branch. During the Cretaceous, the abundance of fungi and wood-boring beetles facilitated a starting domestication of some groups of fungi. First, the fungal spores were accidentally transported from tree to tree by the wood-boring beetles "until this mutually beneficial association evolved towards a more intimate symbiosis in which fungi were inoculated into to a tree, the fungal mycelia grew and beetle larvae fed from the fungus", notes Bjarte Jordal.

This set of factors, together with the symbionts' high ability to adapt and change, eased the morphological and ecological adaptations of biological groups that converged in an obligated mutualism. That is, a symbiotic relationship between insects and fungi, beneficial for both, which still lasts.

"However, we need more studies on the knowledge of the ecology of the species from the Lymexylidae and Bostrichidae families to get more specific conclusions. Therefore, the discovery of new fossils in cretaceous amber of these groups will certainly help us to better understand the evolutionary history of this symbiotic relationship that still exists nowadays", concludes Professor Xavier Delclòs.

CAPTION

The holotype of the species Raractocetus fossilis (Lymexylidae).

CREDIT

Shuhei Yamamoto