Earth

A parasite known only to be hosted in North America by the Virginia opossum is infecting sea otters along the West Coast. A study from the University of California, Davis, elucidates the sometimes surprising and complex pathways infectious pathogens can move from land to sea to sea otter.

For the study, published in the journal Scientific Reports, researchers tested sea otters ranging from Southern California to Alaska for the presence of Sarcocystis neurona, a parasite and important cause of death in sea otters.

They were surprised to find several infected sea otters in the northern part of Vancouver Island in British Columbia, where Virginia opossums -- also known as the North American opossum -- are not known to live. They wondered: Could this parasite travel very long distances in water, or is there an additional unknown host for this pathogen?

To answer this question, the scientists examined spatial patterns and previous research into pathogen transmission, diet and movement of otters. Their results suggest the pathogen may be carried by water runoff from land to sea, where it can be concentrated through ocean movement and prey species, such as clams.

LEARNING FROM OTTERS AND CATS

A related parasite, Toxoplasma gondii, is also known to kill sea otters. Decades of research by a consortium of scientists led by UC Davis School of Veterinary Medicine and the California Department of Fish and Wildlife traced that parasite to another land-based mammal -- wild and domestic cats near watersheds.

"We know S. neurona kills sea otters, and we were pretty sure it comes from the land, but we didn't really know how this pathogen finds them," said lead author Tristan Burgess, a doctoral student in the lab of Christine Kreuder Johnson at the UC Davis One Health Institute at the time of the study. "This new research suggests that there may be a long and complex transmission pathway, a little like the way Toxoplasma finds sea otters, but with a different cast of characters."

RISK FACTORS

Most infections occurred in California and Washington, more so than Alaska and British Columbia. The study found that higher risks of exposure were associated with:

Adult male otters.

Human-dense habitats, some wetlands and croplands.

Wetlands can help filter and deactivate some pathogens, but the study noted they may be potential opossum habitat, as well.

Habitats of soft sediment, like the mouths of rivers and estuaries.

Otters consuming a diet rich in clams, where the parasite may be concentrated.

MARINE MAMMAL SENTINELS

This study highlights risk factors for one species' exposure to one parasite. But it also provides a better understanding of how parasites and infection can move from land to sea to marine mammals.

"Seemingly unimportant species can be important in unexpected ways," Burgess said. "We should also remember the value of marine mammals as sentinels, not just of the health of their marine habitat, but of nearby terrestrial environments, too."

S. neurona may be most familiar to horse owners, as the cause of equine protozoal myeloencephalitis, or EPM. UC Davis developed the diagnostic test for the disease in horses, and it has since been adapted for use in sea otters.

Researchers of the University of Groningen and the Max Planck Institute have found that starlings sleep five hours less per night during the summer. Compared to winter, the birds take more mid-day naps and live under higher sleep pressure. During full-moon nights, starlings sleep around two hours less than usual. The findings of the study were published in the journal Current Biology on 19 March.

Sleep regulation in starling birds is highly flexible and sensitive to environmental factors, according to a new pioneering study conducted by researchers of the UG's Groningen Institute for Evolutionary Life Sciences (GELIFES), the Avian Sleep Group at the Max Planck Institute for Ornithology (Germany) and the Institute of Neuroinformatics, University of Zurich (Switzerland).

Data loggers

In this study, the researchers used miniature electroencephalogram (EEG) data loggers in starlings under semi-natural conditions, meaning the starlings that were housed together in a large outdoor enclosure with natural temperature and light. The results show that the birds displayed strong phenotypical variation in sleep-wake regulation.

Sleep is essential for our wellbeing and performance, yet our understanding of sleep is limited and often based on the studies of a few mammalian model species, conducted under strictly controlled laboratory conditions. Data on sleep in different species under more natural conditions may yield new insights into the regulation and functions of sleep.

Reference: Sjoerd J. van Hasselt, Maria Rusche, Alexei L. Vyssotski, Simon Verhulst, Niels C. Rattenborg, and Peter Meerlo: Sleep Time in the European Starling Is Strongly Affected by Night Length and Moon Phase. Current Biology, 19 March 2020.

On March 17, Federation of European Heating, Ventilation and Air Conditioning Associations REHVA published guidance on the operation and use of building services in areas with a coronavirus disease (COVID-19) outbreak. Representing a network of more than 120.000 engineers from 27 European countries, REHVA guidance complements the general guidance for employers provided by WHO and is targeted to commercial and public buildings.

REHVA Research and Technology Committee chair, professor Jarek Kurnitski from Tallinn University of Technology: "Our document addresses the risk of airborne transmission through small particles (

The document provides practical recommendations which cover ventilation system operation times, use of window airing, safe use of heat recovery sections, no use of recirculation in central ventilation systems as well as on the room level, and some explanation how to avoid overreactions which are easy to happen in situations with limited knowledge.

It is recommended to switch on ventilation systems a couple of hours earlier and also to extend the operation. Better solution is even to keep the ventilation on 24/7, possibly with lowered (but not switched off) ventilation rates when people are absent in order to remove virus particles out of the building. Exhaust ventilation systems of toilets should always be kept on 24/7, and make sure that negative air pressure is created, especially to avoid the faecal-oral transmission.

In buildings without mechanical ventilation systems it is recommended to actively use operable windows so that one could open windows for 15 min when entering the room especially when the room was occupied by others beforehand. Also, in buildings with mechanical ventilation, window airing can be used to further boost ventilation. Opening of windows in toilets should be generally avoided as this may cause a reverse direction operating ventilation and contaminated airflow from the toilet to other rooms.

Recirculation shall not be used, because virus particles in return ducts can re-enter a building in recirculation sectors of centralized air handling units. Thus, recirculation dampers have to be closed via the Building Management System or manually. When possible, decentralized systems such as fan coil units that use local recirculation, also should be turned off to avoid resuspension of virus particles at room level. Similarly to recirculation, heat recovery devices may carry over virus attached to particles from the exhaust air side to the supply air side. In rotary heat exchangers particles deposit on the return air side of the heat exchanger surface after which they might be resuspended when heat exchanger turns to the supply air side. Therefore it is recommended to (temporarily) turn off rotary heat exchangers during SARS-CoV-2 episodes.

It is also important to understand which actions have no practical effect and are not needed. Transmission of some viruses in buildings can be limited by changing air temperatures and humidity levels. In the case of COVID-19 this is unfortunately not an option as the SARS-CoV-2 virus is quite resistant to environmental changes and is susceptible only for a very high relative humidity above 80% and a temperature above 30 ?C, which are not attainable and acceptable in buildings for other reasons (e.g. thermal comfort). Thus, there is no need for humidification, and usually any adjustment of setpoints for heating or cooling systems is not needed. Similarly there is no need to replace outdoor air filters of the ventilation system, which are not a contamination source in this context. Room air cleaners can be useful in specific situations, but the floor area they can effectively serve is normally quite small, typically less than 10 m2. There have been overreactive statements recommending to clean ventilation ducts in order to avoid SARS-CoV-2 transmission via ventilation systems. Duct cleaning is not effective against room-to-room infection because the ventilation system is not a contamination source if given guidance about heat recovery and recirculation is followed.

COVID-19 - REHVA Guidance document: https://www.rehva.eu/activities/covid-19-guidance

Additional information: Head of the Nearly Zero Energy Buildings Research Group at TalTech Department of Civil Engineering and Architecture, Professor Jarek Kurnitski, jarek.kurnitski@taltech.ee

Tropical forest ecosystems are an important part of the global carbon cycle as they take up and store large amounts of CO2. It is however uncertain how much these forests' ability to take up and store carbon differ between forests with high versus low species richness. New IIASA research sheds light on this question aiming to enhance our ability to predict tropical ecosystems' strength as global carbon sinks.

The authors of the new study published in Scientific Reports, investigated how many species are needed for tropical ecosystem functioning and associated ecosystem services, including carbon sequestration, to project future changes in the climate that affect ecosystem carbon storage and thus might trigger further climatic change through increased greenhouse gas emissions. It is important that we are able to construct realistic scenarios of how tropical ecosystems function to help improve current conservation and management strategies, so they can continue to provide their valuable services into the future.

"We wanted to find out how much detail we need to know in order to make valid assumptions in terms of the strength of tropical carbon sinks, in other words, how much carbon is actually sequestered by tropical vegetation? In addition, we wanted to know whether it is biotic factors, that is, differences between plant species that are responsible for capturing more or less carbon from the atmosphere; or if differences are due to abiotic, or local environmental factors like soil properties, that also influence carbon sink strength in tropical ecosystems," explains study lead author Florian Hofhansl, a postdoc researcher with the IIASA Ecosystems Services and Management, and Evolution and Ecology Programs.

According to the researchers, it is generally assumed that more diverse communities capture the available resources more efficiently due to niche complementarity and preferences of certain species to specific conditions. The results show that abiotic and biotic factors in fact interact with one another to determine how much carbon can be stored by the ecosystem based on the availability of other resources like water and nutrients. This indicates that multiple and interrelated factors would need to be accounted for to arrive at plausible projections of future ecosystem carbon sink strength.

An analysis based on statistical path modeling revealed that apart from climatic factors, such as temperature and rainfall, factors like soil texture and chemistry were important controls when it comes to tropical plant community composition as they affect the resource availability of water and nutrients.

In this regard, the study specifically looked at differences between trees, palms, and lianas (long-stemmed, woody vines that use trees and other plants to climb up to the canopy). Each of these groups differ in terms of the amount of carbon they are able to store due to differences in their ecological strategy. Lianas are, for instance, relatively fast growing and try to reach the canopy to get to the sunlight, but do not store as much carbon as a tree stem to reach the same height in the canopy. Palms in turn mostly stay in the understory. The analysis further showed that palms were more abundant on soils with high bulk density and low soil phosphorus availability, while certain tree species were found on relatively less dense soils with high soil water availability leading to differences in plant community composition across the landscape. In addition, sites with less resources contained less diverse plant communities than those with ample soil water and nutrient supply.

Traditional large-scale projections of global change effects on tropical forests however typically ignore the underlying factors triggering differences in plant community composition and, as a consequence, most of the currently applied approaches fail to accurately represent crucial ecosystem processes, such as vegetation carbon storage. This is mainly because remote sensing techniques typically integrate over large spatial areas thus averaging out local landscape diversity, while vegetation models usually ignore the variable response of different plant communities to climatic factors. The authors say that their study results could be used to improve current vegetation models thus allowing scientists to refine projections of tropical forest ecosystem functioning under future climate change scenarios.

"We can only arrive at the right conclusions and provide future projections of how much carbon can be stored if we understand the complexity within ecological systems and what this means for atmospheric feedbacks, such as emissions of greenhouse gases further increasing global warming," says Hofhansl. "Our analyses highlighted that it is important to channel knowledge form multiple scientific disciplines, such as botany (identifying species), plant ecology (identifying functional strategies), and geology (identifying differences in soil types). All of this will determine how much carbon is sequestered by the vegetation and how much of it will remain in the atmosphere, thus further heating up the climate system," he concludes.

Over the past decade, the idea of photonic computing - where electrons are replaced with light in microelectronic circuits - has emerged as a future technology. This promises low-cost, ultra-high-speed and potentially quantum-enhanced computing, with specific applications in high-efficiency machine learning and neuromorphic computing. While the computing elements and detectors have been developed, the need for nanoscale, high-density and easily-integrated light sources remains unmet. Semiconductor nanowires are seen as a potential candidate, due to their small size (on the order of the wavelength of light), the possibility for direct growth onto industry-standard silicon, and their use of established materials. However, to date, such nanowire lasers on silicon have not been demonstrated to operate continuously at room temperature.

In a new paper published in Light Science & Application, scientists from the Photon Science Institute in Manchester, UK with colleagues at University College London and the University of Warwick demonstrate a new route to achieving low-threshold silicon-integratable nanowire lasers. Based on a novel direct-indirect semiconductor heterostructures enabled by the nanowire platform, they demonstrate multi-nanosecond lasing at room temperature. A key design element is the need for high-reflectivity nanowire ends; this is typically a challenging requirement, as common growth methods do not allow simple optimization for high quality end-facets. However, in this study, by employing a novel time-gated interferometer the researchers demonstrate that the reflectivity can be over 70% - around double that expected for a conventional flat-ended laser due to the confinement of light.

Together, the novel material structure and high quality cavity contribute to a low lasing threshold - a measure of the power required to activate lasing in the nanowires - of just 6uJ/cm^2, orders of magnitude lower than previously demonstrated. Not only does this new approach provide high quality nanolasers, but the MBE growth provides a high-yield of functioning wires, with over 85% of nanowires tested working at full power without thermal damage. This high yield is critical for industrial integration of this new structure.

Stratospheric aerosol geoengineering is the idea that adding a layer of aerosol particles to the upper atmosphere can reduce climate changes caused by greenhouse gases such as carbon dioxide.

Previous research shows that solar geoengineering could be achieved using commercially available aircraft technologies to deliver the particles at a cost of a few billion dollars per year and would reduce global average temperatures. However, the question remains whether this approach could reduce important climate hazards at a regional level. That is, could it reduce region-by-region changes in water availability or extreme temperatures?

Results from a new study by UCL and Harvard researchers suggest that even a crude method like injecting sulphur dioxide in the stratosphere could reduce many important climate hazards without making any region obviously worse off.

The findings, published today in Environmental Research Letters, used results from a sophisticated simulation of stratospheric aerosol geoengineering to evaluate whether the approach could offset or worsen the effects of climate change around the world. How these effects differed under different temperature scenarios was also tested.

The team found that halving warming by adding aerosols to the stratosphere could moderate important climate hazards in almost all regions. They saw an exacerbation of the effects of climate change in only a very small fraction of land areas.

Lead author, Professor Peter Irvine (UCL Earth Sciences), said: "Most studies focus on a scenario where solar geoengineering offsets all future warming. While this reduces overall climate change substantially, we show that in these simulations, it goes too far in some respects leading to about 9% of the land area experiencing greater climate change, i.e. seeing the effects of climate change exacerbated.

"However, if instead only half the warming is offset, then we find that stratospheric aerosol geoengineering could still reduce climate change overall but would only exacerbate change over 1.3% of the land area."

The team emphasise that solar geoengineering only treats the symptoms of climate change and not the underlying cause, which is the build-up of CO2 and other greenhouse gases in the atmosphere. It should therefore be considered as a complementary approach to emissions cuts as a way to address climate change.

The study is a follow-up to a paper published last year in Nature Climate Change* showed similar results when solar geoengineering was approximated by simply turning down the sun. That prior study begged the question: would the results hold up with a more realistic simulation using injection of sulphur dioxide, the simplest known method of solar geoengineering.

"Our results suggest that when used at the right dose and alongside reductions in greenhouse gas emissions, stratospheric aerosol geoengineering could be useful for managing the impacts of climate change. However, there are still many uncertainties about the potential effects of stratospheric aerosol geoengineering and more research is needed to know if this idea is truly viable," added Dr Irvine.

The team used data from the Geoengineering Large Ensemble Study, which used a sophisticated climate-chemistry model to simulate the climate response to a hypothetical deployment of stratospheric aerosol geoengineering. In this model study, sulphur dioxide was released at different latitudes in the Tropics to produce a layer of aerosols tuned to keep temperatures steady under an extreme global warming scenario.

The researchers focused on changes in mean and extreme temperature, changes in water availability and changes in extreme precipitation, i.e. climate variables that determine key climate risks.

Previous work suggested that stratospheric aerosol geoengineering could lead to a substantial weakening of monsoons and an intensification of drought. However, the authors found that in those regions where halving warming with stratospheric aerosol geoengineering exacerbated change, it increased water availability rather than reduced it. This suggests that concerns that stratospheric aerosol geoengineering could lead to aridification and drought could be misplaced.

Co-author, Professor David Keith (Harvard's Engineering and Applied Sciences and Kennedy school), said: "Early research with climate models consistently shows that spatially uniform solar radiation modification could significantly reduce climate risks when combined with emissions cuts. But, should we trust the models? Uncertainties are deep and no single result is trustworthy, but this paper is a step towards more realistic modelling from injection to regional impacts."

The team are now researching the projected effects of stratospheric aerosol geoengineering on the water cycle in more depth to try to understand the potential benefits and risks to society and ecosystems.

Adult Pacific salmon spend a great portion of their life in the ocean. But their life began along the banks of freshwater streams. Their life will end there, as well. These important steps in the lifecycle of salmon play a role in the health of streambank ecosystems.

David D'Amore and a team of scientists studied how different soils respond to the delivery of "salmon-derived nutrients." These nutrients come from adult salmon returning to their home streams, known as spawning. The study sites were forested ecosystems in Alaska's coastal temperate rainforest.

Aquatic and terrestrial scientists have studied salmon derived nutrients in these systems, but D'Amore set out to see if there was a difference in how these nutrients worked with varying soil types along the streambanks.

"The fate of salmon-derived nutrients will be influenced by the soil type in the riparian zone," says D'Amore. "These soils play an important role in the transfer of material and energy between terrestrial and aquatic environments. The nutrients provided by salmon can support microbial and plant growth. In turn, these organisms support the salmon and other animals that rely on food from the streambank ecosystems."

"Soils along the streams resulted from a series of alluvial deposits after the glaciers retreated," says D'Amore. "Two alluvial deposits were formed during the last ice age, resulting in two different soils. An older terrace formed Spodosols, rich in organic matter. They also have highly enriched organic-metal complexes. But there are also younger floodplain soils with little development. These two soil types offer a stark contrast in attributes such as acidity, cation exchange capacity, and organic matter - all which affect how well nutrients are absorbed and held in soil."

This difference in how the two soil types worked with salmon-derived nutrients added the novel twist for the research done by D'Amore's team.

Salmon begin life along the banks of streams that flow past the alluvial soils of the coastal rainforests. Once the salmon emerge from their egg nests, they are nurtured by the nutrients that support the food web in the stream. There, they are also protected by the woody debris of large conifers that fall into the stream. Once they are large enough to survive in the ocean, the salmon depart the freshwaters to spend 2-4 years in the nutrient-rich waters of the North Pacific. The adult salmon then return to their natal streams from the ocean to close the life cycle loop.

"Our study found that both nitrogen and phosphorus decreased over time, but were retained in the soils and could be available to plants in the riparian zone over the duration of the spawning cycle," says D'Amore. "Although the extractable nitrogen and phosphorus amounts did not differ between soil types, the way the nutrients were processed did. We also found that over time - and location - there were differences in the way these salmon-derived nutrients were used."

The findings in this study revealed the potential for contrasting nutrient cycling pathways between the two soil types. "Future research work will focus on the fate of nitrogen through leaching and denitrification," says D'Amore.

"In addition, we plan to look at nitrogen and phosphorus, along with their physical and biological compartments, to determine the ultimate fate of the salmon-derived nutrients. The link between the nutrient subsidy and increased plant growth needs to be more closely examined, especially in the spatial context of the soils and their different nutrient retention characteristics."

Media reporting of suicide, especially celebrity suicides, is associated with increases in suicide in the general population, particularly by the same method as used by the celebrity, finds an analysis of the latest evidence published by The BMJ today.

The researchers say their findings support the continued use and promotion of guidelines on responsible media reporting of suicide, especially when reporting on deaths of celebrities by suicide.

A linked editorial suggests that tighter control of media reporting of suicide may be required.

News reporting of suicide has increased substantially in recent decades, and a number of studies have shown instances where media reports about suicide are associated with increased rates of suicide.

As a result, guidelines for responsible reporting of suicide by the media are now a standard component of many suicide prevention strategies. But until now, evidence of an association between media reporting and suicide has not been entirely consistent.

To address this knowledge gap, a team of international researchers examined the association between reporting on suicides, especially celebrity suicides, and subsequent suicides in the general population.

They also assessed whether reporting on the specific methods of celebrity suicide was associated with suicides by the same method, and whether general reporting of suicide (any reporting or general discussion on the topic of suicide) was linked to suicide.

Their analysis is based on the results of 20 studies that compared at least one time point before and up to two months after reports of death by suicide on TV, in print or online news, or in non-fiction books or films.

The studies were designed differently, and were of varying quality, but the researchers were able to allow for that in their analysis.

Reporting of celebrity suicide appeared to increase the number of suicides by 8-18% in the next 1-2 months, and information on method of suicide was associated with an increase of 18-44% in the risk of suicide by the same method.

To put this into context, in the UK, where 6,507 people died by suicide in 2018 (542 per month), a 13% increase would amount to around 70 additional deaths. In the five months following the death of the international celebrity Robin Williams by suicide, deaths by suicide increased by almost 10% (1,841) in the United States.

General reporting of suicide did not appear to be associated with suicide, although the researchers cannot rule out associations for certain types of reporting.

Several mechanisms could explain these results, including identification with the deceased person, and increased reporting leading to a normalisation of suicide as an acceptable way to cope with difficulties, explain the researchers.

The patterns identified in this analysis suggest that media stories on celebrity suicides might increase suicidal thoughts and also contribute to planning suicide with a specific method, they write.

They point to some limitations, such as being unable to test causality due to the designs of the original studies, and high levels of variation between studies which could not be fully accounted for.

But say this study provides the clearest evidence so far that reporting on suicide, especially celebrity suicides, is associated with increases in suicide in the general population.

"The best available intervention at the population level to deal with the harmful effects of media reports is guidelines for responsible reporting," they write. "These guidelines should be more widely implemented and promoted, especially when reporting on deaths of celebrities by suicide," they conclude.

These findings will help give media outlets a clearer sense of the potential effect of their reporting, say researchers at the University of Bristol in a linked editorial.

They argue that detail, sensationalism, and accounts of the methods used are unnecessary and harmful, while easy access to online information presents particular hazards.

They suggest that tighter control of media reporting of suicide may be required. Journalists and news editors "must consider more carefully the costs to population health of sensationalist, detailed reporting of these tragic deaths," they conclude.

In 2016, ocean temperatures soared, devastating the corals of Australia's Great Barrier Reef. As the frequency, duration and magnitude of these marine heatwaves increases due to human-induced climate change, scientists have yet to fully grasp the physiological, behavioral, and long-term consequences for wild fish populations.

Researchers in the Marine Climate Change Unit at the Okinawa Institute of Science and Technology Graduate University (OIST), in collaboration with scientists from the ARC Centre of Excellence for Coral Reef Studies, James Cook University in Australia and the University of Hong Kong, have studied patterns of gene expression in five species of coral reef fish collected at different points before, during, and after the 2016 heatwave. Through these analyses, the scientists identified species-specific physiological responses to the heightened temperatures; these responses were influenced by the intensity and duration of the heatwave.

These changes likely signal long-term consequences for the fitness of fishes - and the health of marine ecosystems - as extreme heat events increase in frequency. The results of the study are published in Science Advances.

Collecting and analyzing fish

To carry out their research, the scientists sampled five species from two families of coral reef fish from Lizard Island, off the northeast coast of Australia. The researchers began sampling before the predicted heatwave in December, then at the start of the heatwave in February 2016, finishing after the fish had endured prolonged exposure to high temperatures in July 2016.

The researchers studied damselfishes and cardinalfishes, which are abundant and relatively easy to catch. In addition, damselfish are diurnal, while cardinalfish are nocturnal, meaning they swim and eat at night when temperatures are lower.

The scientists froze the specimens and transported them back to the lab. Upon analyzing gene expression patterns in the livers of the fish, they found molecular changes related to metabolism, stress, and respiration, tied to both short-term and prolonged heat exposure.

Their molecular evidence suggests that different tropical fishes respond to warming in different ways, meaning that genetic background has a significant influence on the way that fish can acclimatize or adapt to climate change; some fish are more vulnerable than others.

"These varied responses are important because when scientists do experiments, or target commercial species, we cannot generalize based on geography or on one or two species that have been studied in the lab," said Professor Timothy Ravasi, the leading author of the study. "This has important ramifications for policy makers and for the fishing industry."

Regardless of species, the researchers found that the physiological responses of the fish to the heatwaves depended on the intensity and duration of the heatwaves.

Moving forward, Ravasi and his team hope to continue examining the immediate consequences of anthropogenic climate change by studying how repeated episodes of warming could influence fish and their long-term adaptation. Ravasi intends to simulate heatwaves in controlled environments to see how different temperatures and different periods of exposure affect fish.

Although it's important to examine the long-term implications of climate change, Ravasi said, his paper emphasizes the importance of looking at the short-term.

"Over time, the fish may adapt to rising temperatures, or they'll migrate to cooler waters," he said. "But these heatwaves are happening now, and it's necessary for the field to understand the immediate consequences.

An ancient Elpistostege fish fossil found in Miguasha, Canada has revealed new insights into how the human hand evolved from fish fins.

An international team of palaeontologists from Flinders University in Australia and Universite du Quebec a Rimouski in Canada have revealed the fish specimen, as described in the journal Nature, has yielded the missing evolutionary link in the fish to tetrapod transition, as fish began to foray in habitats such as shallow water and land during the Late Devonian period millions of years ago.

This complete 1.57 metre long fish shows the complete arm (pectoral fin) skeleton for the first time in any elpistostegalian fish. Using high energy CT-scans, the skeleton of the pectoral fin revealed the presence of a humerus (arm), radius and ulna (forearm), rows of carpus (wrist) and phalanges organized in digits (fingers).

"Today we announce in the journal Nature our discovery of a complete specimen of a tetrapod-like fish, called Elpistostege, which reveals extraordinary new information about the evolution of the vertebrate hand," says Strategic Professor in Palaeontology at Flinders University Professor John Long.

"This is the first time that we have unequivocally discovered fingers locked in a fin with fin-rays in any known fish. The articulating digits in the fin are like the finger bones found in the hands of most animals."

"This finding pushes back the origin of digits in vertebrates to the fish level, and tells us that the patterning for the vertebrate hand was first developed deep in evolution, just before fishes left the water."

The evolution of fishes into tetrapods - four-legged vertebrates of which humans belong - was one of the most significant events in the history of life.

Vertebrates (back-boned animals) were then able to leave the water and conquer land. In order to complete this transition- one of the most significant changes was the evolution of hands and feet.

In order to understand the evolution from a fish fin to a tetrapod limb, palaeontologists study the fossils of lobe-finned fish and tetrapods from the Middle and Upper Devonian (393-359 million years ago) known as 'elpistostegalians'.

These include the well-known Tiktaalik from Arctic Canada, known only from incomplete specimens.

Co-author Richard Cloutier from Universite du Quebec a Rimouski says over the past decade, fossils informing the fish-to-tetrapod transition have helped to better understand anatomical transformations associated with breathing, hearing, and feeding, as the habitat changed from water to land on Earth.

"The origin of digits relates to developing the capability for the fish to support its weight in shallow water or for short trips out on land. The increased number of small bones in the fin allows more planes of flexibility to spread out its weight through the fin. "

"The other features the study revealed concerning the structure of the upper arm bone or humerus, which also shows features present that are shared with early amphibians. Elpistostege is not necessarily our ancestor, but it is closest we can get to a true 'transitional fossil', an intermediate between fishes and tetrapods."

Elpistostege was the largest predator living in a shallow marine to estuarine habitat of Quebec about 380 million years ago. It had powerful sharp fangs in its mouth so could have fed upon several of the larger extinct lobe-finned fishes found fossilised in the same deposits.

Background

Elpistostege was originally named from just a small part of the skull roof, found in the fossiliferous cliffs of Miguasha National Park, Quebec, and described in 1938 as belonging to an early tetrapod.

Another part of the skull of this enigmatic beast was found and described in 1985, demonstrating it was really an advanced lobe-finned fish. The remarkable new complete specimen of Elpistostege was discovered in 2010.

Meticulous preparation of the new specimen and CT scanning of the fossil took place in Quebec in 2010 with Prof Cloutier working with Isabelle Bechard to do the initial interpretation of the scan data, and Vincent Roy and Roxanne Noel to analyse the backbone and fin structures.

How we farm can guard against climate change and protect critical wildlife - but only if we leave single-crop farms in the dust, according to a new Stanford study.

The research provides a rare, long-term look at how farming practices affect bird biodiversity in Costa Rica. "Farms that are good for birds are also good for other species," said Jeffrey Smith, a graduate student in the department of biology and a co-author on the paper. "We can use birds as natural guides to help us design better agricultural systems."

By and large, the team found that diversified farms are more stable in the number of birds they support, provide a more secure habitat for those birds and shield against the impacts of climate change much more effectively than single-crop farms.

"The tropics are expected to suffer even more intensely in terms of prolonged dry seasons, extreme heat and forest dieback under climate change," said Gretchen Daily, director of the Stanford Natural Capital Project and the Center for Conservation Biology and a senior author on the paper. "But diversified farms offer refuge - they can buffer these harmful effects in ways similar to a natural forest ecosystem."

The findings, published in this week's issue of the journal Nature, highlight the importance of farms that grow multiple crops in a mixed setting instead of the more common practice of planting single-crop "monocultures."

"This study shows that climate change has already been impacting wildlife communities, continues to do so, and that local farming practices really matter in protecting biodiversity and building climate resilience," said Nick Hendershot, a graduate student in the department of biology and lead author on the study.

Threatened in the tropics

Tropical regions are some of the most species-rich in the world, but they also face the greatest threats to biodiversity. As their forests are felled to plant cash crops like bananas and sugarcane, the amount and availability of natural habitats have shrunk dramatically. Meanwhile, climate change has resulted in longer, hotter dry seasons that make species survival even more challenging.

"It's the one-two punch of land-use intensification and climate change," Hendershot said. "Wildlife populations are already severely stressed, with overall decreased health and population sizes in some farming landscapes. Then, these further extreme conditions like prolonged drought can come along and really just decimate a species."

Until now, little had been known about how agricultural practices impact biodiversity in the long term. This study's researchers used nearly 20 years of meticulously collected field data to understand which birds live in natural tropical forests and in different types of farmland.

"It is only because we had these unusually extensive long-term data that we were able to detect the role of diversified farmlands in helping threatened species persist over multiple decades," said Tadashi Fukami, an associate professor of biology in the School of Humanities and Sciences and a senior author on the paper, along with Daily.

The varied agricultural systems at work in Costa Rica provided the research team with an ideal laboratory for studying bird communities in intensively farmed monoculture systems, diversified multi-crop farms, and natural forests. They compared monoculture farms - like pineapple, rice, or sugar cane - to diversified farms that interweave multiple crops and are often bordered by ribbons of natural forest.

Who's there matters

Surprisingly, the researchers found that diversified farmlands not only provide refuge to more common bird species, they also protect some of the most threatened. Species of international conservation concern, like the Great Green Macaw and the Yellow-naped Parrot, are at risk in Costa Rica due to habitat loss and the illegal pet trade.

In intensive monocrop farmlands, these species are declining. But in the diversified systems the researchers studied, the endangered birds can be found year after year.

"Which species are in a given place makes a huge difference - it's not just about numbers alone, we care about who's there," Daily said. "Each bird serves a unique role as part of the machinery of nature. And the habitats they live in support us all."

Changing the paradigm

In Costa Rica and around the world, the researchers see opportunities to develop integrated, diversified agricultural systems that promote not only crop productivity and livelihood security, but also biodiversity. A paradigm shift towards global agricultural systems could help human and wildlife communities adapt to a changing climate, Daily said.

"There are so many cash crops that thrive in diversified farms. Bananas and coffee are two great examples from Costa Rica - they're planted together, and the taller banana plant shades the temperature-sensitive coffee bean," she added. "The two crops together provide more habitat opportunity than just one alone, and they also provide a diversified income stream for the farmer."

In a sampling of fish from a creek that flows into San Diego Bay, nearly a quarter contain microplastics, according to a new study published in the journal PLOS ONE. The study, which examined plastics in coastal sediments and three species of fish, showed that the frequency and types of plastic ingested varied with fish species and, in some cases, size or age of fish.

The study reveals that species' natural history, in particular what they eat, how they feed, and how those change over their lifetimes, may influence their contamination levels. This new information on how plastics travel through the environment and into fish could help add a key piece to the emerging picture of the dynamics and impacts of plastics in California's coastal environment.

"Over the last two decades, we have started to realize the huge extent to which small plastics are entering our marine ecosystems from urban watersheds," says study lead author Theresa Talley, a California Sea Grant Extension Specialist and researcher at Scripps Institution of Oceanography at the University of California San Diego. "But there are still many questions to answer."

Much of this plastic enters ocean from land-based sources, and rivers--especially urban rivers--are major conduits for the flow of trash from land to sea. However, there are still a lot of questions about what happens to plastics as they break down and move through the environment, how they affect the wildlife that may consume them, what other contaminants they carry and transmit, how they move through the food web, and what impacts that environmental plastics may have on people who may be exposed to them through seafood consumption.

To better understand the impacts and movement of plastic through an urban watershed and the fish that inhabit it, Talley and colleagues focused their study on the highly urbanized Chollas Creek. The creek flows from a densely populated area of San Diego into San Diego Bay--reported to be the second-most polluted bay in the country.

Tiny threads, big problem

Research on environmental microplastics is not a job for people who are easily grossed out. To gather the samples they needed, the team tromped through muddy tidal creeks to trap fish and gather sediment samples. They took them back to the lab where they examined the sediments and dissected the fish guts--painstakingly combing through grains of sand and half-digested food under a microscope and cataloging everything they saw, from algae to plastic fibers, by size, color, and type.

The team identified 25 categories of plastics in the sediments, including pieces of film, polystyrene, soft and hard plastic, microbeads, and synthetic fibers, with the fibers and both hard and soft pieces making up 90% of fragments found on the creek bed. The fish, in contrast, seemed to consume only about half of the categories of plastic observed in the environment.

"The most common types of plastics we saw in the fish guts were synthetic fibers and hard pieces. We also noticed that many of the plastics resembled other prey items in the fish guts raising the question of whether some plastics are mistaken as food," says UC Davis PhD student Nina Venuti, who worked on the project as a California Sea Grant research assistant.

Comparing across species, the team also found differences in the types of plastics consumed. For example, California killifish were more likely to have consumed microbeads, often used in personal care and cleaning products. Further, the team found that larger, and therefore older, California killifish were also more apt to have plastics in their guts.

"If we want to reduce the risks that plastic pollution poses to sea life and, ultimately humans, we need to better understand the processes underlying the entry of plastics into food webs," says Talley, "It's no longer enough to document all the places we find plastics. If we want to develop solutions, we need a clearer understanding of how and why the plastics move through ecosystems."

Exotic subatomic particles that are like 'normal' particles apart from one, opposite, property - such as the positron, which is like an electron but positively rather than negatively charged - are collectively known as antimatter. Direct studies of collisions between particles of matter and those of antimatter using giant facilities such as those at CERN can advance our understanding of the nature of matter. A new study by Tasko Grozdanov from the University of Belgrade in Serbia and Evgeni Solov'ev from the Institute of Nuclear Research near Moscow in Russia has mapped the energy levels of an exotic form of helium produced in this way. This work, which is published in EPJ D, has been described by one commentator as '... a new jewel in the treasure of scientific achievements in atomic physics theory".

An atom of ordinary helium consists of a nucleus with two protons and two neutrons surrounded by two electrons. Experiments at CERN have involved colliding slow antiprotons with these helium atoms to form an exotic form of helium called antiprotonic helium, in which one of the electrons is replaced with an antiproton (a particle like a proton but with the negative charge of an electron). Thus, an atom of antiprotonic helium is uncharged, like ordinary helium, but includes one negatively-charged particle over 1800 times heavier than an electron.

Antiprotonic helium atoms can only survive in configurations in which the antiproton cannot 'fall' into the nucleus and annihilate. Until now, the only widely studied configuration involves antiproton making circular orbits around the nucleus, shielded by the remaining electron. Grozdanov and Solov'ev describe a different configuration, named a 'frozen planet' state, in which the electron rapidly circulates round the nucleus, generating a potential well that traps the antiproton. The period of time in which the antiproton can remain trapped in this well depends on its energy and the distance from the nucleus. The researchers plan to extend their studies to include similar configurations that rotate, which they suggest may be more amenable to experimental research.

Infants from rural families tend to display negative emotions such as anger and frustration more frequently than their urban counterparts, according to a recent study in the Journal of Community Psychology.

Babies born in big cities, on the other hand, typically are less fussy and not as bothered by limits set by their caregivers.

The study, led by Washington State University psychologist Maria Gartstein and WSU graduate student Alyssa Neumann, examines differences in infant temperament, parent-child interactions and parenting stress between families of similar socioeconomic and racial composition in the Inland Northwest and the San Francisco Bay Area.

The researchers found urban moms tend to be better at picking up on when their babies wanted or needed something, or were ready to be done with play, and responding accordingly. This in turn could have led to their infants generally being calmer and less easily upset.

Rural moms reported more frequent expressions of negative emotions from their infants, particularly when they were distressed due to limitations.

The results of Gartstein and Neumann's work in many ways reflect the findings of previous research investigating differences in child-rearing practices between urban and rural families. However, unlike past studies, which have looked at the effects of living in an urban vs. rural environment on older children, Gartstein and Neumann's analysis specifically focuses on infants.

"I was shocked, quite frankly, at how little there was in the literature on the effects of raising an infant in a rural vs. urban environment," Gartstein said. "The fact that rural mothers in our study reported more frequent expressions of anger and frustration from their infants may be consequential as higher levels of frustration in infancy can increase risk for later attentional, emotional, social and behavioral problems."

Gartstein said the next step in the research will be to try to pinpoint exactly what it is about living in a rural vs. urban context that causes the differences in temperament between the two groups.

"For example, access to mental and behavioral health services and child rearing resources tend to be limited in more rurally situated communities," she said. "Figuring out what role, if any, these and other locational variables play in an infant's social emotional development will be the next step in our research."

For the study, Gartstein, Neumann, and colleagues at the University of Louisville School of Medicine and the Seattle Clinic analyzed and compared data from two previously conducted studies of mother-child interactions and infant temperament.

The first study consisted of 68 participants and their infants in the San Francisco Bay Area, and the second consisted of 120 rural mothers and their infants from Whitman and Latah counties in the Inland Northwest of the United States.

Mothers used a questionnaire to record the frequency of 191 different behaviors their child displayed at six and 12 months after birth. The researchers then analyzed babies along 14 different dimensions that ranged from cuddliness to vocal reactivity.

Parent-child interactions, where mothers were instructed to engage their infants in play in a typical fashion, were also video-recorded in the laboratory for analysis.

Gartstein said one of the more surprising findings from the study was that contrary to predictions, her team found no statistically significant differences in levels of parenting stress between urban and rural caregivers.

"This may be a result of different, but functionally equivalent, risk factors," Gartstein said. "Whereas living in a big city generally brings more exposure or proximity to violent crime, isolation can also cause a great deal of stress for rural parents. This research opens up a lot of very interesting future avenues of investigation."

Gartstein's infant temperament research will also be featured in an episode of the Netflix documentary "Babies" this summer.

Irvine, Calif., March 18, 2020 - During the exceptionally warm Arctic summer of 2019, Greenland lost 600 billion tons of ice, enough to raise global sea levels by 2.2 millimeters in two months. On the opposite pole, Antarctica continued to lose mass in the Amundsen Sea Embayment and Antarctic Peninsula but saw some relief in the form of increased snowfall in Queen Maud Land, in the eastern part of the continent.

These new findings and others by glaciologists at the University of California, Irvine and NASA's Jet Propulsion Laboratory are the subject of a paper published today in the American Geophysical Union journal Geophysical Research Letters.

"We knew this past summer had been particularly warm in Greenland, melting every corner of the ice sheet, but the numbers are enormous," said lead author Isabella Velicogna, UCI professor of Earth system science and JPL senior scientist.

Between 2002 and 2019, Greenland lost 4,550 billion tons of ice, an average of 268 billion tons annually - less than half what was shed last summer. To put that in perspective, Los Angeles County residents consume 1 billion tons of water per year.

"In Antarctica, the mass loss in the west proceeds unabated, which is very bad news for sea level rise," Velicogna said. "But we also observe a mass gain in the Atlantic sector of East Antarctica caused by an increase in snowfall, which helps mitigate the enormous increase in mass loss that we've seen over the last two decades in other parts of the continent."

She and her colleagues came to these conclusions in the process of establishing data continuity between the recently decommissioned Gravity Recovery and Climate Experiment satellite mission and its new and improved successor, GRACE Follow-On.

A project of NASA and the German Aerospace Center, the twin GRACE satellites were designed to make extremely precise measurements of changes in Earth's gravity. The spacecraft have proven to be particularly effective at monitoring the planet's water reserves, including polar ice, global sea levels and groundwater.

The first GRACE mission was deployed in 2002 and collected data for more than 15 years, a decade longer than its intended life span. Toward the end of this period, the GRACE satellites began to lose battery power, leading to the end of the mission in October 2017.

GRACE Follow-On - based on a similar technology but also including an experimental instrument using laser interferometry instead of microwaves to gauge minute changes in distance between the twin spacecraft - was launched in May 2018. The gap between the missions made it necessary for Velicogna and her cohort to test how well data amassed by the GRACE and GRACE-FO missions matched.

"It's great to see how well the data line up in Greenland and Antarctica, even at the regional level," she said. "It's a tribute to the months of effort by the project, engineering and science teams to make the endeavor successful."