Leaves Are Nature's Most Sophisticated Environment Sensors
February 6th, 2019
New research confirms that leaves are nature's most sophisticated environment sensors. We can therefore use leaves to tell us about the management of the land they are growing in.
Professor of Zoology, Yvonne Buckley at Trinity College Dublin is part of a global network of grassland ecologists who have found that critical plant nutrients such as nitrogen, phosphorus and potassium in leaves respond to fertilisation treatments as well as the climate and soils they are growing in. The discovery has just been published in Nature Ecology & Evolution.
While ecologists and agricultural scientists have known for some time that individual species at individual locations can vary in the amounts of these nutrients in their leaves in response to fertilisation, this is the first time that it has been confirmed across entire communities of plants in very different climates and soil conditions. The experiment was undertaken at 27 sites in four continents, from the semiarid grasslands and savannas of Australia to lush pastures in Europe and prairies in America.
When plants are fertilised they can use those extra nutrients to grow bigger and produce more flowers and seeds which can dilute the nutrients in their leaves, so a positive response of leaf nutrients to fertilisation is not guaranteed. A surprising result of this experiment was that Specific Leaf Area, a leaf trait that is commonly used to tell us about how plants defend themselves against herbivores and capture sunlight for growth, was unaffected by fertilisation. So this critical measure of leaf architecture is not changing in a consistent way in response to fertilisation. Leaf architecture is instead determined by climate and soil characteristics, so it may respond over a longer time frame than short-term fertilisation.
Commenting on the significance of the research, Professor Buckley said:
"As our environment changes more quickly due to climate change, intensification of agriculture and land use, it is becoming more important to understand how grasslands all over the world are likely to respond. Grasslands are one of the most extensive habitats in the world, they provide us with food, carbon storage and habitat for pollinators. Using plants as sensors of environmental change gives us another important tool for understanding the consequences of these changes for our life support systems."
"There are two ways that leaf nutrients can change in grassland communities, either the existing species leaves change to store more nutrients or the kinds of species which can survive in these new conditions change to species that naturally have higher leaf nutrients. We found that for nitrogen and potassium both of these things were happening but for phosphorus the species change pathway was not important."
The lead author of the paper is Professor Jennifer Firn from Queensland University of Technology with Professor Buckley as a co-author.
Jennifer Firn, James M. McGree, Eric Harvey, Habacuc Flores-Moreno, Martin Schütz, Yvonne M. Buckley, Elizabeth T. Borer, Eric W. Seabloom, Kimberly J. La Pierre, Andrew M. MacDougall, Suzanne M. Prober, Carly J. Stevens, Lauren L. Sullivan, Erica Porter, Emma Ladouceur, Charlotte Allen, Karine H. Moromizato, John W. Morgan, W. Stanley Harpole, Yann Hautier, Nico Eisenhauer, Justin P. Wright, Peter B. Adler, Carlos Alberto Arnillas, Jonathan D. Bakker, Lori Biederman, Arthur A. D. Broadbent, Cynthia S. Brown, Miguel N. Bugalho, Maria C. Caldeira, Elsa E. Cleland, Anne Ebeling, Philip A. Fay, Nicole Hagenah, Andrew R. Kleinhesselink, Rachel Mitchell, Joslin L. Moore, Carla Nogueira, Pablo Luis Peri, Christiane Roscher, Melinda D. Smith, Peter D. Wragg, Anita C. Risch. Leaf nutrients, not specific leaf area, are consistent indicators of elevated nutrient inputs. Nature Ecology & Evolution, 2019; DOI: 10.1038/s41559-018-0790-1
A Survey On Ticks And Wildlife In The Northern Beaches
The University of Sydney is conducting a study to better understand how residents and their pets are encountering ticks and wildlife in their backyards. We invite all Northern Beaches residents to participate in our survey.
Coastal bushland remnants and other green spaces across the Northern Beaches are home to a variety of native plants and animals. They also provide a place for residents to enjoy their favourite outdoor pastimes. Paralysis ticks (Ixodes holocyclus) are common in the Northern Beaches and feed on a wide range of animal hosts during their life cycle. Understanding the complex relationship between ticks and their host species is an essential part of our research. The information we gain will contribute to our growing knowledge of ticks and will guide future research efforts.
We aim to identify:
- Areas where people are encountering ticks more than others (tick 'hotspots'),
- Backyard and landscape features that may influence tick presence, and
- Wildlife using backyards and how this might or might not influence tick occurrence
To meet these aims, it is important for you to provide a street address. If you would prefer not to, we ask that you provide your street name and nearest cross street. It is important for us to create a map of tick encounters to understand what landscape features might influence tick presence and where to target future research.
All identifying information will be removed from any data presentations.
The survey should only take approximately 10 minutes to complete and is voluntary.
If you have any questions about the project, please contact PhD candidate Casey Taylor on 02 9351 3189 or casey.taylor@sydney.edu.au. This project is being undertaken by the University of Sydney in association with Northern Beaches Council.
Your participation is greatly appreciated.
This research has been approved by the University of Sydney Human Ethics committee. (Approval no: 2018/157)
NSW Back Of The Pack For Renewables
February 7th, 2019
Lack of leadership on energy policy in NSW has been laid bare again today with the release of the latest Green Energy Markets report, which found NSW sources more of its power from coal than any other state in Australia. [1]
“In December, NSW sourced just 13.5% of its power from renewables, including hydro,” Nature Conservation Council Climate Campaigner Dr Brad Smith said.
“Meanwhile Victoria gets 18% of its power from clean sources, and South Australia gets 52.7%.”
The research and advisory business also found the energy mix in NSW had barely changed in a decade, with 78.5% of the state’s energy still coming from coal.
“NSW is still at the back of the pack when it comes to clean energy because the Berejikian government doesn’t have target for clean energy,” Dr Smith said.
“The state Labor Opposition haven’t announced a clean energy policy either, so voters are right to wonder where is the political leadership?
“We need all the parties to lift their level of ambition and make strong commitments that will rapidly transition the state’s energy supply away from coal and into clean, modern sources like solar backed up with storage and batteries.reliable renewables.”
The Nature Conservation Council and other climate action groups are calling on all parties to ensure:
- The NSW Government tenders for 4000 MW of large-scale clean power by 2023 (the next term of government).
- All government operations are powered with renewable energy, including schools and public hospitals, by 2023.
- Every household (including low-income and rental properties) can access solar power by 2029 through a Solar For All Rebate and by helping families with solar install batteries.
- Legislate net-zero carbon emissions by 2040 and ensure all government decisions consider the impact of policies on climate change.
POLICY: Clean Energy Future for NSW
REFERENCES: [1] SMH 7/2/2019 Renewables reach highest share of Australia's power in 40 years
City Of Sydney To Host Major 2020 Women’s Climate Summit
February 4th, 2019: City of Sydney
Sydney Lord Mayor Clover Moore today announced that the City of Sydney has been selected to host a major international climate conference in 2020.
The C40 Women4Climate Conference is an initiative of the C40, a network of 94 of the world’s largest cities, representing more than 700 million people worldwide.
Under the leadership of its former and current chairs – Michael Bloomberg and the Mayor of Paris, Anne Hidalgo – the organisation has taken over 10,000 practical actions to tackle climate change.
“For too long, many national governments have failed to take action to address accelerating climate change, so cities are leading the way”, Lord Mayor Clover Moore said.
“More than half of the world’s population live in cities, and generate a staggering 75 to 80 per cent of the world’s greenhouse gas emissions, so action in our cities is crucial.
“Shamefully, our own national government has a history of wilful negligence and Australian politicians, both state and federal, are presiding over a climate disaster.
“Just this month in Australia, we’ve experienced the hottest month on record, unprecedented fish kills in the Murray-Darling river system and bushfires in Tasmania; while in the northern hemisphere people are dying in extreme freezing temperatures.
“Australia remains the largest exporter of coal in the world and until recently our state sourced more than 90 per cent of electricity from coal-fired power. Our National Government’s 2020 and 2030 emissions targets are profoundly inadequate and Australia’s greenhouse gas emissions have been steadily increasing since the carbon tax was removed in 2013.”
The Lord Mayor said action on climate change is the City of Sydney’s top priority, and this conference would provide an opportunity to showcase the leadership of Sydney to the world.
“The City was among the first to set science-based targets in 2008 and since then we’ve reduced our emissions by 20 percent on 2005 levels, and are well on our way to achieving our 2030 goal of 70 per cent, and net zero by 2050,” the Lord Mayor said.
“We were inspired by Los Angeles to convert our 6,500 streetlights to LED more than a decade ago. Now our local energy provider Ausgrid is converting almost 10,000 more. This action alone is our largest carbon reduction project to date.
“The City has worked with our business community through the Better Buildings Partnership. Members have saved $33 million a year on power costs and reduced their emissions by 52 per cent since 2001, well over halfway to their 2030 target of a 70 per cent reduction.
“But our challenge is huge because of the lack of support from our state and national governments.”
“I hope that by hosting this major international conference, we can give voice to the majority of ordinary Australians who believe the science and want action but who are silenced by the powerful vested interests in our country, and help encourage one of the world’s highest producers of greenhouse gas emissions into taking more ambitious action.”
The City of Sydney will host the annual conference for three days in April 2020, bringing together hundreds of influential women leaders from government, business industry and the community sector to tackle climate change issues.
“As part of our successful bid, we’ve also committed to developing a 10 month mentoring program to empower Sydney’s next generation of female climate leaders by connecting them with the current successful female climate change leaders,” said the Lord Mayor.
The Women4Climate initiative was founded by Paris Mayor and C40 Chair Anne Hidalgo in 2016 to enhance women’s participation and leadership to secure a healthy, prosperous and sustainable future.
Lord Mayor Clover Moore, the CEO of the City of Sydney Monica Barone and the Lord Mayor’s chief of staff, Shehana Teixeira will travel to the 2019 C40 Women4Climate Conference in Paris later this month.
For more information on C40 Cities, visit: https://www.c40.org/
Australia Streaks Ahead To Be Renewables World Champion
February 8th, 2019: ANU
Research from The Australian National University (ANU) has found that Australia is installing renewable power per person each year faster than any other country, helping it to meet its entire Paris Agreement emissions reduction targets five years early.
Lead researcher Professor Andrew Blakers said Australia was installing renewable power per capita several times faster than the European Union, Japan, China and the United States, based on preliminary data available for installations globally last year.
"The installation of renewables in Australia last year really ramped up compared to these other major economies, and we expect that trend to continue this year and beyond," said Professor Blakers from the ANU Research School of Electrical, Energy and Materials Engineering (RSEEME).
"The electricity sector is on track to deliver Australia's entire Paris emissions reduction targets five years early, in 2025 - without the need for any creative accounting.
"Australia is on track to reach 50 per cent renewable electricity in 2024 and 100 per cent by 2032. The Australian renewable energy experience offers real hope for rapid global emissions reductions to preserve a living planet."
Co-researcher Dr Matthew Stocks said the net cost of achieving the 2030 carbon emission targets set in the Paris Agreement would be zero because expensive fossil fuels were being replaced by cheaper renewables.
"The price of electricity from large-scale solar PV and windfarms in Australia is currently about $50 per Megawatt-hour (MWh), and steadily falling," Dr Stocks said.
"This is below the cost of electricity from existing gas-fired power stations and is also below the cost of new-build gas and coal power stations. Nearly all of the new power stations are either PV or wind. We anticipate that this will continue into the future, provided that energy policy is not actively hindering development."
Co-researcher Bin Lu said stabilising a 100 per cent renewable electricity grid would be possible with technology that is already widely used in Australia, in addition to new smart energy systems that are being developed for electricity grids.
"We can do this with energy storage, demand management and strong interstate connection using high-voltage transmission lines to smooth out the effect of local weather," Mr Lu said.
"By far the leading storage technologies are pumped hydro and batteries. Australia's coal power stations are old and are becoming less reliable, and transition to a modern renewable energy system can improve grid stability."
Pumped hydro energy storage sites such as Snowy 2.0 require pairs of reservoirs at different altitudes, in hilly terrain and joined by a pipe with a pump and turbine. Water is pumped uphill when wind and solar energy is plentiful, and electricity is available on demand by releasing the stored water through a turbine.
A report on the team's findings is available at: http://re100.eng.anu.edu.au/news/2019-02-06.php
L-R Dr. Matthew Stocks, Professor Andrew Blakers and Bin Lu Image Credit - ANU
Nano-Infused Ceramic Could Report On Its Own Health
February 5th, 2019: Rice University
A ceramic that becomes more electrically conductive under elastic strain and less conductive under plastic strain could lead to a new generation of sensors embedded into structures like buildings, bridges and aircraft able to monitor their own health.
The electrical disparity fostered by the two types of strain was not obvious until Rice University's Rouzbeh Shahsavari, an assistant professor of civil and environmental engineering and of materials science and nanoengineering, and his colleagues modeled a novel two-dimensional compound, graphene-boron-nitride (GBN).
Under elastic strain, the internal structure of a material stretched like a rubber band does not change. But the same material under plastic strain -- caused in this case by stretching it far enough beyond elasticity to deform -- distorts its crystalline lattice. GBN, it turns out, shows different electrical properties in each case, making it a worthy candidate as a structural sensor.
Shahsavari had already determined that hexagonal-boron nitride -- aka white graphene -- can improve the properties of ceramics. He and his colleagues have now discovered that adding graphene makes them even stronger and more versatile, along with their surprising electrical properties.
The magic lies in the ability of two-dimensional, carbon-based graphene and white graphene to bond with each other in a variety of ways, depending on their relative concentrations. Though graphene and white graphene naturally avoid water, causing them to clump, the combined nanosheets easily disperse in a slurry during the ceramic's manufacture.
The resulting ceramics, according to the authors' theoretical models, would become tunable semiconductors with enhanced elasticity, strength and ductility.
The research led by Shahsavari and Asghar Habibnejad Korayem, an assistant professor of structural engineering at Iran University of Science and Technology and a research fellow at Monash University in Melbourne, Australia, appears in the American Chemical Society journal Applied Materials and Interfaces.
Ceramics with networked nanosheets of graphene and white graphene would have the unique ability to alter their electrical properties when strained, according to a researcher at Rice University. The surprising ability could lead to new types of structural sensors. Credit: Rouzbeh Shahsavari/Rice University
Graphene is a well-studied form of carbon known for its lack of a band gap -- the region an electron has to leap to make a material conductive. With no band gap, graphene is a metallic conductor. White graphene, with its wide band gap, is an insulator. So the greater the ratio of graphene in the 2D compound, the more conductive the material will be.
Mixed into the ceramic in a high enough concentration, the 2D compound dubbed GBN would form a network as conductive as the amount of carbon in the matrix allows. That gives the overall composite a tunable band gap that could lend itself to a variety of electrical applications.
"Fusing 2D materials like graphene and boron nitride in ceramics and cements enables new compositions and properties we can't achieve with either graphene or boron nitride by themselves," Shahsavari said.
The team used density functional theory calculations to model variations of the 2D compound mixed with tobermorite, a calcium silicate hydrate material commonly used as cement for concrete. They determined the oxygen-boron bonds formed in the ceramic would turn it into a p-type semiconductor.
Tobermorite by itself has a large band gap of about 4.5 electron volts, but the researchers calculated that when mixed with GBN nanosheets of equal parts graphene and white graphene, that gap would shrink to 0.624 electron volts.
When strained in the elastic regime, the ceramic's band gap dropped, making the material more conductive, but when stretched beyond elasticity -- that is, in the plastic regime -- it became less conductive. That switch, the researchers said, makes it a promising material for self-sensing and structural health monitoring applications.
The researchers suggested other 2D sheets with molybdenum disulfide, niobium diselenide or layered double hydroxides may provide similar opportunities for the bottom-up design of tunable, multifunctional composites. "This would provide a fundamental platform for cement and concrete reinforcement at their smallest possible dimension," Shahsavari said.
Ehsan Hosseini, Mohammad Zakertabrizi, Asghar Habibnejad Korayem, Rouzbeh Shahsavari. Tunable, Multifunctional Ceramic Composites via Intercalation of Fused Graphene Boron Nitride Nanosheets. ACS Applied Materials & Interfaces, 2019; DOI: 10.1021/acsami.8b19409
See-Through Fish Aid Scientists In Autism-Related Breakthrough
February 6th, 2019
University of Miami researchers have discovered a clue in the humble zebrafish's digestive tract that, one day, could help people on the autism spectrum alleviate one of the most common yet least studied symptoms of their disorder: gastrointestinal distress.
By replicating a mutation in zebrafish that causes a rare, autism-related genetic condition known as Phelan-McDermid Syndrome in humans, the researchers found a drastic reduction in the number of cells that produce serotonin in the mutant zebrafish's gut. Perhaps better known as the body's natural mood stabiliser, serotonin also initiates the contractions that move food through the digestive system.
Published last week in the journal Molecular Autism, the study is the first to show that a mutation of a particular autism-associated gene, SHANK3, causes food to move through the digestive tract at an abnormally slow pace. While the finding applies to zebrafish, a common freshwater aquarium species that shares about 70 percent of its genes with humans, it could explain why many people with an autism spectrum disorder, and particularly those with Phelan-McDermid Syndrome (PMS), often suffer severe and disruptive bouts of constipation, diarrhoea, reflux, and/or cyclical vomiting.
More importantly, it could open the door to treatments that alleviate such unpleasant gastrointestinal, or GI, symptoms.
"The fact that we see reduced motility in the GI tract of fish with shank3 mutations is likely explained by the absence of these serotonin-producing cells, and that suggests that if we could find a way to increase motility we might be able to help with the GI problem," said senior author Julia Dallman, associate professor of biology whose UM lab studies inherited nervous system disorders by modelling them in zebrafish. "One issue in autism right now is that a lot of the drugs given to kids with autism to address their behavioural issues actually make their gut function worse. So by having a model of gut function we can try to find treatments that don't make it worse."
Dallman and two of her graduate students, David M. James and Robert A. Kozol, the first co-authors of the study, began earnestly modelling GI distress in zebrafish after they were invited to the 2016 biennial meeting of the international Phelan-McDermid Syndrome Foundation in Orlando. There they heard firsthand accounts from parents of children born with PMS which, caused by a deletion or mutation of the SHANK3 gene at the end of chromosome 22, is characterised by moderate to severe intellectual disabilities and developmental delays, absent or delayed speech, decreased muscle tone, and epileptic seizures.
Yet, despite all those very daunting challenges, parents often expressed deep frustration over their child's GI issues, which affected their quality of life on a daily basis, often making ordinary routines and milestones, like eating and toilet-training, exceedingly difficult.
"At that time, there hadn't been much published about GI issues in our community, but when you listen to parents they would always talk about how troubling it was," said Geraldine Bliss, past chair of the foundation's research support committee."There was a whole constellation of issues -- sometimes diarrhoea, sometimes constipation, sometimes alternating diarrhoea and constipation, reflux -- all kinds of GI problems, but it hadn't really been characterised or reported in the literature."
Now, the common zebrafish and James' interest in characterising GI issues in autism seem destined to help shed light on the confounding problem.
About an inch long at maturity, the zebrafish is a valuable model for human disease because, aside from having a similar genetic structure to humans, it develops rapidly and, until its second week of life, is almost completely transparent. That's when it begins developing the telltale dark stripes for which it is named.
That early transparency, coupled with an apparent zeal for what juveniles consider yummy food, enabled James and Kozol to record what happens when zebrafish lacking the shank3 gene digested chicken egg yolks, which were infused with tiny, florescent-green tracking beads. The films clearly showed that the mutant fish not only had slower and less frequent gut contractions than normal zebrafish, but that the ingested food particles got stuck in the junction between the stomach and the intestine for prolonged periods of time.
The reason came as a surprise. Initially, the researchers hypothesised the shank3 mutation somehow damaged the fish's enteric nervous system -- the "brain" that controls the gut -- but that was perfectly normal. Instead, the researchers found the shank3 mutants had drastically fewer serotonin-producing cells than their wild-type counterparts.
"It was definitely an 'Aha!' moment," James said. "It opens up a lot, in terms of studying potential mechanisms for how all this dysmotility is occurring. If we can figure that out, we can start talking about what the proper treatments are, and what's going to fix this -- that's the real question."
The answer may lie in the distant future, but this first crucial step in unraveling a biological reason for autism-related GI distress is heartening to members of the PMS foundation, which began as a family support group in 1998, when 20 of the 23 families then known to be affected by a deletion or mutation of chromosome 22 first met.
Today, nearly 200 affected families from around the world attend the foundation's meetings, the last of which was held in Texas last summer. That's when James presented UM's research on intestinal dysmotility in zebrafish, which not only won the conference's research award but gave parents like Gail Fenton hope for a better future for their children.
"Joanna's tummy troubles have been a major source of family stress for 15 years," Fenton wrote from Australia about her 36-year-old daughter. "She is often hunched over because of tummy pain. She cries, even yells, when her tummy is sore. She'll always have Phelan-McDermid Syndrome but her life, and the lives of fellow sufferers with these complex GI issues, would be so much happier without these negatives and we are so very thankful for the research that can lead to any helpful interventions."
David M. James, Robert A. Kozol, Yuji Kajiwara, Adam L. Wahl, Emily C. Storrs, Joseph D. Buxbaum, Mason Klein, Baharak Moshiree, Julia E. Dallman. Intestinal dysmotility in a zebrafish (Danio rerio) shank3a;shank3b mutant model of autism.Molecular Autism, 2019; 10 (1) DOI: 10.1186/s13229-018-0250-4