Category: Environment

{An unnatural balance of nutrients threatens biodiversity in a survival of the fittest scenario, according to the results of a world-first global experiment published in the journal Nature. Professor Jennifer Firn, from QUT’s Science and Engineering Faculty, is part of a global network of researchers who have tested the impact increased nutrient levels is having on grasslands across six continents.}

The article is titled “Addition of multiple limiting resources reduces grassland diversity” and was led by Professor Stan Harpole from UFZ and iDIV, Germany.

“As part of the Nutrient Network, researchers tested the Charles Darwin ‘entangled bank’ observation which is used to explain how species can coexist even if they require the same limiting resources.

“This theory explains the mechanism of how a number of species should be competing for resources when they are actually coexisting because of the subtle differences in their resource needs.

“But what we found was that if you change the limiting resources and add an abundance of resources such as nutrients like phosphorus, nitrogen and potassium, it will lead to a favouring of some species over others because competition is then shifted above ground for light.

“This will in turn evoke competition between species, leading to one species dominating the land area.”

The experiment was conducted across 45 grassland sites spanning the multi-continent Nutrient Network.

Professor Firn said the human influence on the nutrient cycle through greater globalisation, was having a damaging effect on ecosystem biodiversity.

“The loss of diversity was not driven by the addition of any single added resource for example nitrogen or potassium, we found greatest diversity loss occurred with the addition of a combination of two or more resources,” she said.

“Simply put, the more nutrients, the less biodiversity.”

She said many of the ecosystem functions that humans need to survive were provided by richly diverse ecosystems, such as oxygen production, water filtration, nutrient cycling, pollination, and carbon sequestration.

“The irreplaceable loss of native biodiversity is accelerating at an alarming rate globally,” she said.

“What this research does is provide tangible evidence that global change is driving environmental conditions beyond our planetary boundaries.”

The Nutrient Network is the only collaborations of its kinds in which individual researchers have set up the same experiments at sites around the world. It is coordinated through the US-based National Science Foundation’s funding to biologists Prof. Elizabeth Borer and Prof. Eric Seabloom of the University of Minnesota.

{Indoor air pollution is an important environmental threat to human health, leading to symptoms of “sick building syndrome.” But researchers report that surrounding oneself with certain house plants could combat the potentially harmful effects of volatile organic compounds (VOCs), a main category of these pollutants. Interestingly, they found that certain plants are better at removing particular harmful compounds from the air, suggesting that, with the right plant, indoor air could become cleaner and safer.}

The researchers are presenting their work today at the 252nd National Meeting & Exposition of the American Chemical Society (ACS). ACS, the world’s largest scientific society, is holding the meeting here through Thursday. It features more than 9,000 presentations on a wide range of science topics. A brand-new animation on the research is available at http://bit.ly/ACSindoorairpollution.

“Buildings, whether new or old, can have high levels of VOCs in them, sometimes so high that you can smell them,” says Vadoud Niri, Ph.D., leader of the study.

VOCs are compounds like acetone, benzene and formaldehyde that are emitted as gases and can cause short- and long-term health effects when inhaled. They can come from paints, furniture, copiers and printers, cleaning supplies and even dry-cleaned clothes.

“Inhaling large amounts of VOCs can lead some people to develop sick building syndrome, which reduces productivity and can even cause dizziness, asthma or allergies,” Niri says. “We must do something about VOCs in indoor air.”

The most common solution is to install ventilation systems that cycle in air from outside. There are also methods that can remove these compounds, using adsorption, condensation and chemical reactions.

However, Niri is studying a cheap, simple tool to remove VOCs: house plants. Using plants to remove chemicals from indoor air is called biofiltration or phytoremediation. In addition to carbon dioxide, plants can take up gases such as benzene, toluene and other VOCs. NASA began studying this option in 1984 and found that plants could absorb these airborne compounds via their leaves and roots.

Since then, other studies have looked at how plants phytoremediate specific compounds, such as the carcinogen formaldehyde, in a closed space. Most of these studies focused on the removal of single VOCs by individual plants from the ambient air. However, Niri wanted to compare the efficiency and the rate of simultaneous removal of several VOCs by various plants.

To test this, Niri, who is at the State University of New York at Oswego (SUNY Oswego), and his team built a sealed chamber containing specific concentrations of several VOCs. They then monitored the VOC concentrations over several hours with and without a different type of plant in the chamber. For each plant type, they noted which VOCs the plants took up, how quickly they removed these VOCs from the air, and how much of the VOCs were ultimately removed by the end of the experiment.

The researchers tested five common house plants and eight common VOCs, and they found that certain plants were better at absorbing specific compounds. For example, all five plants could remove acetone — the pungent chemical that is abundant at nail salons — from the air, but the dracaena plant took up the most, around 94 percent of the chemical.

“Based on our results, we can recommend what plants are good for certain types of VOCs and for specific locations,” Niri says. “To illustrate, the bromeliad plant was very good at removing six out of eight studied VOCs — it was able to take up more than 80 percent of each of those compounds — over the twelve-hour sampling period. So it could be a good plant to have sitting around in the household or workplace.”

Niri says the next step in the research is to test these plants’ abilities in a real room, not just a sealed chamber. He would eventually like to put plants in a nail salon over the course of several months to see whether they can reduce the levels of acetone that workers are exposed to.

{A group of southern elephant seals is helping scientists monitorhow climate change is impacting Antarctica by tracking water temperature, depth, and salinity as they swim and dive around the frozen continent.}

Most recently, data from the seals — which routinely dive to depths of 1,000 to 2,000 feet — showed that water melting off the Antarctic ice sheet is causing the surrounding seas to become less salty, disrupting a conveyor belt-like system that transfers heat and nutrients around the globe.

The new findings were published this week in the journal Nature Communications. The elephant seal data, as well as records from monitoring devices on other marine mammals, have generated more than 500,000 vertical profiles of temperature and salinity in the world’s oceans and helped inform nearly 100 scientific studies. “”At the moment it’s all about filling gaps” in the environmental records, lead author Guy Williams of the University of Tasmania told the Australian Broadcasting Corporation. “The [seals] have gone to areas where we’ve never had an observation before.”

{Many people suffer from anxiety and fears, and a common treatment for these problems is exposure therapy. In a new study, researchers have shown how the effect of exposure therapy can be improved by disrupting the recreation of fear-memories in people with arachnophobia.}

Studies show that up to 30 per cent of all people suffer an anxiety disorder at some point in their lives. Anxiety leads to great suffering for those affected, but can be treated with exposure therapy, in which the patient is gradually exposed to the object or context that provokes the reactions. If exposure therapy is successful, a new ‘safe’ memory is formed, which overshadows the old fear memory. But not everyone is helped by this treatment, in part because the learning that takes place during the treatment is not permanent; the memory may return at some point later on after an initially successful exposure. Memory researchers have now demonstrated that the improvement can be made more lasting.

When a person is reminded of something, the memory becomes unstable and is re-saved. If you disrupt the re-saving of the memory, so-called reconsolidation, the creation of the memory can be disrupted and the memory that is saved can be changed. A fear memory could thus be weakened or erased, and this offers hope for improved treatment of anxiety disorders. But until now there has been doubt if this would be possible because older and stronger memories have proven to be difficult to disrupt.

In a study published in the journal Current Biology, researchers from Uppsala University and Karolinska Institutet in Sweden have now for the first time shown that it is possible to use this method to reduce fear in life-long phobias. The researchers exposed individuals with arachnophobia to spider pictures while measuring their brain activity in the amygdala, a part of the brain that is strongly linked to fear.

They found that an activation of the fear memory, consisting of a mini-exposure 10 minutes before a more extensive exposure, led to significantly reduced amygdala activity when the subjects looked at the spider pictures again the following day. Because the memory is made unstable before exposure and re-saved in its weakened form, the fear does not return as easily. The day after exposure, the group that received an initial activation of their spider fear showed reduced amygdala activity in comparison with a control group. Avoidance of spiders also decreased, which could be predicted from the degree of amygdala activation.

‘It is striking that such a simple manipulation so clearly affects brain activity and behaviour. A simple modification of existing treatments could possibly improve effects. This would mean more people getting rid of their anxieties after treatment and fewer relapses,’ says Johannes Björkstrand, PhD student at the Department of Psychology, Uppsala University.

{An international research project has found human activity has been causing global warming for almost two centuries, proving human-induced climate change is not just a 20th century phenomenon.}

Lead researcher Associate Professor Nerilie Abram from The Australian National University (ANU) said the study found warming began during the early stages of the Industrial Revolution and is first detectable in the Arctic and tropical oceans around the 1830s, much earlier than scientists had expected.

“It was an extraordinary finding,” said Associate Professor Abram, from the ANU Research School of Earth Sciences and ARC Centre of Excellence for Climate System Science.

“It was one of those moments where science really surprised us. But the results were clear. The climate warming we are witnessing today started about 180 years ago.”

The new findings have important implications for assessing the extent that humans have caused the climate to move away from its pre-industrial state, and will help scientists understand the future impact of greenhouse gas emissions on the climate.

“In the tropical oceans and the Arctic in particular, 180 years of warming has already caused the average climate to emerge above the range of variability that was normal in the centuries prior to the Industrial Revolution,” Associate Professor Abram said.

The research, published in Nature, involved 25 scientists from across Australia, the United States, Europe and Asia, working together as part of the international Past Global Changes 2000 year (PAGES 2K) Consortium.

Associate Professor Abram said anthropogenic climate change was generally talked about as a 20th century phenomenon because direct measurements of climate are rare before the 1900s.

However, the team studied detailed reconstructions of climate spanning the past 500 years to identify when the current sustained warming trend really began.

Scientists examined natural records of climate variations across the world’s oceans and continents. These included climate histories preserved in corals, cave decorations, tree rings and ice cores.

The research team also analysed thousands of years of climate model simulations, including experiments used for the latest report by the UN’s Intergovernmental Panel on Climate Change (IPCC), to determine what caused the early warming.

The data and simulations pinpointed the early onset of warming to around the 1830s, and found the early warming was attributed to rising greenhouse gas levels.

Co-researcher Dr Helen McGregor, from the University of Wollongong’s School of Earth and Environmental Sciences, said humans only caused small increases in the level of greenhouse gases in the atmosphere during the 1800s.

“But the early onset of warming detected in this study indicates the Earth’s climate did respond in a rapid and measureable way to even the small increase in carbon emissions during the start of the Industrial Age,” Dr McGregor said.

The researchers also studied major volcanic eruptions in the early 1800s and found they were only a minor factor in the early onset of climate warming.

Associate Professor Abram said the earliest signs of greenhouse-induced warming developed during the 1830s in the Arctic and in tropical oceans, followed soon after by Europe, Asia and North America.

However, climate warming appears to have been delayed in the Antarctic, possibly due to the way ocean circulation is pushing warming waters to the North and away from the frozen continent.

{Study challenges distinctiveness of human cooperation.}

Tasks that require chimpanzees to work together preferred five-fold, despite opportunities for competition, aggression and freeloading.

When given a choice between cooperating or competing, chimpanzees choose to cooperate five times more frequently Yerkes National Primate Research Center researchers have found. This, the researchers say, challenges the perceptions humans are unique in our ability to cooperate and chimpanzees are overly competitive, and suggests the roots of human cooperation are shared with other primates. The study results are reported in this week’s early online edition of the Proceedings of the National Academy of Sciences.

To determine if chimpanzees possess the same ability humans have to overcome competition, the researchers set up a cooperative task that closely mimicked chimpanzee natural conditions, for example, providing the 11 great apes that participated in this study with an open choice to select cooperation partners and giving them plenty of ways to compete. Working beside the chimpanzees’ grassy outdoor enclosure at the Yerkes Research Center Field Station, the researchers gave the great apes thousands of opportunities to pull cooperatively at an apparatus filled with rewards. In half of the test sessions, two chimpanzees needed to participate to succeed, and in the other half, three chimpanzees were needed.

While the set up provided ample opportunities for competition, aggression and freeloading, the chimpanzees overwhelmingly performed cooperative acts — 3,565 times across 94 hour-long test sessions.

The chimpanzees used a variety of enforcement strategies to overcome competition, displacement and freeloading, which the researchers measured by attempted thefts of rewards. These strategies included the chimpanzees directly protesting against others, refusing to work in the presence of a freeloader, which supports avoidance as an important component in managing competitive tendencies, and more dominant chimpanzees intervening to help others against freeloaders. Such third-party punishment occurred 14 times, primarily in response to aggression between the freeloader and the chimpanzee that was cooperatively working with others for the rewards.

“Previous statements in the literature describe human cooperation as a ‘huge anomaly’ and chimpanzees as preferring competition over collaboration,” says Malini Suchak, PhD, lead author of the study. “Studies have also suggested researchers have to ‘engineer cooperation’ during experiments rather than acknowledging chimpanzees are naturally cooperative. When we considered chimpanzees’ natural behaviors, we thought surely they must be able to manage competition on their own, so we gave them the freedom to employ their own enforcement strategies. And it turns out, they are really quite good at preventing competition and favoring cooperation. In fact, given the ratio of conflict to cooperation is quite similar in humans and chimpanzees, our study shows striking similarities across species and gives another insight into human evolution,” she continues. Suchak was a graduate student at the Yerkes Research Center at the time of the study and is now an Assistant Professor of Animal Behavior, Ecology and Conservation at Canisius College in Buffalo, NY.

Frans de Waal, PhD, director of the Living Links Center at the Yerkes Research Center, a C. H. Candler Professor of Psychology at Emory University and one of the study authors, adds, “It has become a popular claim in the literature that human cooperation is unique. This is especially curious because the best ideas we have about the evolution of cooperation come straight from animal studies. The natural world is full of cooperation, from ants to killer whales. Our study is the first to show that our closest relatives know very well how to discourage competition and freeloading. Cooperation wins!”

{The April 2015 Gorkha earthquake in Nepal killed more than 8,000 people and injured more than 21,000. With a magnitude of 7.8, it was the worst natural disaster to strike Nepal since the 1934 Nepal-Bihar earthquake. Researchers have now discovered complex relationship between major earthquake faulting and mountain building in the Himalayas.}

The April 2015 Gorkha earthquake in Nepal killed more than 8,000 people and injured more than 21,000. With a magnitude of 7.8, it was the worst natural disaster to strike Nepal since the 1934 Nepal-Bihar earthquake.

Researchers Kelin Whipple, Manoochehr Shirzaei, Kip Hodges, and Ramon Arrowsmith of ASU’s School of Earth and Space Exploration were quick to begin analyzing the data from this quake. Their findings have been recently published in Nature Geosciences.

The earthquake triggered numerous rock slides and avalanches, including one that obliterated the mountain village of Langtang, leaving few survivors. Elsewhere, entire villages were flattened by intense shaking, leaving thousands of people homeless and many hundreds missing.

“The days immediately after the earthquake were intense. We were very stressed by the rising death toll, and concerned for the many Nepalese guides and researchers we had worked with over the years,” Whipple said.

Despite the well-known association between seismic activity and mountain ranges, the Gorkha earthquake actually worked against long-term mountain building by uplifting the foothills and down-dropping the mountains. By studying this event and its counter-intuitive outcome, ASU researchers shed new light on the mechanisms of mountain building.

{{Building Earth’s highest mountain range}}

The Himalaya, the most dramatic mountain range on Earth, is a manifestation of the ongoing collision between India and Asia. Exactly how the Himalaya were built, however, has long been debated.

The conundrum is that major thrust faults that accommodate convergence between tectonic plates are usually relatively flat, tilted no more than a few degrees from horizontal, and thus do not produce much uplift.

How, then, can we explain the existence of dramatic mountain ranges like the Himalaya?

Some collisional mountain ranges grow because there are “ramps” or steep segments on major thrust faults that produce the rock uplift that builds high topography.

In the Himalaya, the region of high topography is set back some 80 kilometers north of the active frontal thrust, leading to the conventional wisdom that the Himalaya grow by slip on a ramp beneath the High Himalaya. Whipple and colleagues realized that the Gorkha earthquake, while tragic, provided an opportunity to test this hypothesis.

{{Satellite data provide clues to how the Himalayas were built}}

Even when seismic ruptures occur ~10 kilometers beneath the surface, as was the case of the Gorkha event, an earthquake causes patterns of deformation (uplift, subsidence and lateral shifts) that can reveal the geometry of the fault surface, or surfaces, involved.

Using data from Global Positioning System (GPS) stations and Interferometric Synthetic Aperture Radar (InSAR) images collected during successive satellite fly-overs, ASU researchers were able to measure changes in surface elevation during a time period spanning the main Gorkha event, and several major aftershocks, with centimeter accuracy.

“Within hours of the event, it was clear from seismic data that the main rupture had occurred on a gently sloping thrust fault, but just 10 days later InSAR data was suggesting a more complex scenario — and a possible resolution of an old debate,” said Whipple.

ASU researchers modeled these changes to show that the major active thrust fault remains relatively flat underneath the High Himalaya, inconsistent with the existence of the ramp often hypothesized to explain uplift of the range. This is fundamentally why the Gorkha earthquake actually uplifted the foothills and down-dropped the mountains.

{{So how are the Himalaya built?}}

With the newly collected data, the researchers could see, in exquisite detail, physical evidence of a likely secondary rupture during the earthquake and its aftershocks that actually uplifted a portion of the High Himalaya northeast of Kathmandu. The secondary fault implicated is directly analogous to the fault responsible for the devastating 2005 Kashmir earthquake that claimed more than 85,000 lives in Pakistan.

It appears that slip on this structure, and perhaps others like it, may contribute more to the continued growth of the mountains than large ruptures on the main active thrust fault. Interestingly, steep secondary thrusts may develop in response to rapid erosion focused in the High Himalaya.

Ultimately, these findings not only provide a greater understanding of the mountain building process, they also may help anticipate seismic hazards in advance of devastating earthquakes by improving our ability to remotely identify active faults.

“To those that live at the foot of the Himalaya and other tectonically active mountain ranges, understanding the seismic hazard is of tantamount importance,” said Whipple.

{A Bosnian pine (Pinus heldreichii) growing in the highlands of northern Greece has been dendrocronologically dated to be more than 1075 years old. This makes it currently the oldest known living tree in Europe. The millenium old pine was discovered by scientists from Stockholm University (Sweden), the University of Mainz (Germany) and the University of Arizona (USA).}

“It is quite remarkable that this large, complex and impressive organism has survived so long in such an inhospitable environment, in a land that has been civilized for over 3000 years” says Swedish dendrochronologist, Paul J. Krusic, leader of the expedition that found the tree. It is one of more than a dozen individuals of millennial age, living in a treeline forest high in the Pindos mountains.

“Many years ago I read a thesis about this very interesting forest in Greece. In our research, we try to build long chronologies to construct climate histories, so finding living trees of old age is one of our motivations. To age the tree, we needed to take a core of wood, from the outside to the center. The core is one meter and has 1075 annual rings” says Krusic.

The scientists hope the annual variations of the tree rings from trees like this and those fallen in centuries past, yet still preserved on the ground, will provide an informative history of climatic and environmental conditions, going back thousands of years. Considering where the tree was found, and its venerable age, the scientists have named this individual “Adonis” after the Greek god of beauty and desire.

“I am impressed, in the context of western civilization, all the human history that has surrounded this tree; all the empires, the Byzantine, the Ottoman, all the people living in this region. So many things could have led to its demise. Fortunately, this forest has been basically untouched for over a thousand years” says Krusic.

The millennium old trees were discovered during research expeditions conducted by the Navarino Environmental Observatory (NEO), a cooperation between Stockholm University, the Academy of Athens and TEMES S.A. The observatory studies climate change and its impact on environment and humans in the Mediterranean.

{{Timeline:}}

941 — Adonis is a seedling. The Byzantine Empire is at its peak. From the North, the Vikings reach the Black Sea.

1041 — Adonis is a 100 years old. In China, a book is published describing gunpowder. A man called Macbeth is crowned King of Scotland.

1191 — Adonis is 250 years old. The universities of Oxford and Paris are founded. The third crusade battles Saladin in the Holy Land.

1441 — Adonis is 500 years old. The Ottoman empire conquers Greece. Many Greek scholars flee to the west, influencing the Renaissance. In Sweden, the first parliament is held in Arboga. Johannes Gutenberg is about to test his first printing press.

1691 — Adonis is 750 years old. Isaac Newton has formulated his Laws on Motion. Ice cream, tea and coffee are introduced in Europe.

1941 — Adonis is a millennium old. World War II is ravaging the world. Greece is occupied by Nazi Germany, Italy and Bulgaria.

{When the weather is hot, zebra finches in Australia sing to their eggs – and these “incubation calls” change the chicks’ development, a study has found.}

The surprising discovery suggests that the birds are preparing their offspring for warm conditions after they hatch.

Scientists collected eggs and incubated them in controlled conditions, playing recordings of the incubation song.

Compared to a control group, hatchlings that received these calls grew more slowly and coped better in the heat.

Writing in the journal Science, the researchers say this is the sort of adaptation that could help animals acclimatise to rising global temperatures.

“It doesn’t mean that they will still be able to breed at extreme temperatures – this was within the range they currently experience,” said the paper’s lead author Mylene Mariette, from Deakin University in Geelong.

“But what’s encouraging is that it’s a strategy that the birds use to adjust the growth of their offspring to temperature, that we didn’t know about.”

It is also the first time that singing to unborn chicks has been shown to yield such long-term results.

{{Baby, it’s hot outside}}

Previous studies have mostly concentrated on egg-bound embryos learning particular calls from their parents.

“We knew it could have some short-term effects on cognition and learning, but our study is the first to show that is has an effect on their growth and their development – and that those effects last until adulthood,” Dr Mariette told BBC News.

“It means that the acoustic environment before birth has more impact than we thought.”

She first noticed the rhythmic, high-pitched calls while making field recordings during her PhD.

“I was looking at how the parents talk to each other to coordinate parental care.That’s when I noticed that sometimes when a parent was by itself in the nest, incubating the egg, it produced a quite different call.

“I wondered – hmm, are they talking to their eggs?”

When she started to study this squeaky serenade in detail, combing through Dr Mariette found that the birds were specifically singing it in the few days before eggs hatched – and only when the day’s ambient temperature rose above about 26C.
“It’s not that they do it spontaneously whenever it’s hot; they do it when it’s hot and when the embryos could potentially hear them,” she said.

To figure out the specific effect of the calls, Dr Mariette and her colleague Katherine Buchanan used zebra finches living in the university’s outdoor aviaries.

They collected eggs and, for the final five days of their incubation, played them either a recording of the birds’ special egg-song, or a typical parent-to-parent call instead.
As soon as they hatched, the 175 chicks were returned to various nests and the team observed the youngsters’ development in detail.

To begin with, the two groups were indistinguishable; the song hadn’t changed the chicks’ hatching weight.

Within a few days, however, that changed.

“We found that, depending on whether or not they had heard the ‘hot call’ from their parents, they reacted differently to heat,” Dr Mariette explained.

“They adjusted their growth to temperature differently, and also solicited food from their parents differently.”

Specifically, the “heat song” seemed to make the chicks develop slower – and remain lighter – if their nest was in a hot corner of the aviary.

Being a lightweight is generally bad news in evolutionary terms, but when the researchers followed the finches’ fortunes into adulthood, it proved the opposite: those lighter birds that grew up in hot nests produced significantly more fledglings than their heavier childhood companions.

{{Information transfer}}

Furthermore, the chicks that were primed with a “heat song” in the egg went on to prefer warmer nesting spots.

“It’s as if the parents are preparing the chicks for the temperature they will experience after hatching,” said Dr Mariette.

It is a mystery, she added, how being smaller gives the birds an advantage in the heat. But it may be because growing in hot conditions is costly for the body, placing more oxidative stress on tissues – so staying small becomes a better strategy.

This could also help explain why, as global temperatures rise, wild bird populations in general are slowly shrinking – though mostly, that process has been seen to have negative consequences for the species involved.

Whatever their evolutionary implications, the Deakin team’s findings are an intriguing case of communication between parents and unborn offspring.

Nicola Hemmings, a research fellow studying bird reproduction at Sheffield University in the UK, said the experiments were elegantly designed and the results convincing.
“They’ve shown that not only can parents teach their offspring a call while they’re still in the egg – but that they’re giving them quite specific information about the environment they’re about to hatch into,” she told the BBC.

Just like the study’s authors, Dr Hemmings said she was fascinated by what might be driving the changes in the chicks’ development.

“They’re not actually thinking, ‘Mum says it’s hot out there, I better take it slow when I get outside!’ But it’s having some kind of physiological effect on their body which is making their growth rate slow.

“Does it have a hormonal basis? Is it a stress response? That would be the interesting thing to look at next.”