australia – Australian Science

The Future of Solar Power Technologies in Australia

Dunya — Fri, 18 Apr 2014 00:15:17 +0000

As the cost of fossil fuels go up around the world, and the impact of climate change becoming increasingly avoidable, people are looking for reliable, alternative sources of energy. With the favourable climate in Australia, it’s a no-brainer that solar power is the way forward. But gone are the days of inefficient panels at extraordinary prices – and Australian researchers are leading the way.

Cutting edge solar panels

About solar power

Solar power is fast becoming the top choice for families and businesses looking to cut down on their electricity bills and minimise their impact on climate change. In the past, the cost was inhibiting, but as technology improves and costs come down – it is being rapidly implemented.

Solar power can be used for a variety of purposes – some use it in combination with standard energy while others use it as a sole energy provider. It can also be used as a standalone technology to heat a hot water system, which can be a popular choice as heating can account for up to 70 per cent of energy bills.

In the past, solar energy could only be captured and used at that same moment – but now, solar systems are able to store energy during the day and then release it at night, making it a much more practical choice.

Australia and solar power

Australia is a global leader in solar power technology. There are nearly 17,000 people employed full-time in the solar industry and there are now over one million solar power systems installed across the country, compared to just 8,000 in 2007.

A 2013 report into Australia’s solar energy future found that despite Australia being the world’s sunniest continent, solar energy was largely underutilised. However, it also found that the price of solar power systems were dropping so fast that in some areas the cost was almost competitive with standard electricity companies, and the cost of installation was less than a quarter of the price a decade ago. (Flannery, T., 2013)

Solar station in White Cliffs

Current solar power technology

Solar power technology has come a long way even in just the past few years, and Australians now have numerous options when it comes to choosing a solar energy solution. Options include manufacturers, materials used and the technology within the solar panels, too.

There are three main types of solar panels – polycrystalline, monocrystalline and amorphous modules. There are numerous others, but these are the most popular choices due to efficiency, cost and aesthetics. For example, monocrystalline tend to be the most efficient, but are not as cheap as polycrystalline is cheaper to produce. In the past few years, though, the cost of monocrystalline panels have dropped – making them the most popular choice for Australians.

Future of solar power

It is estimated that by 2050, solar power will account for 29 per cent of Australia’s energy needs. (Flannery, T., 2013) To achieve this, technology needs to be continually advancing – and new solar technology is already on its way, with Australia leading the research. Here are a few key developments happening in Australia right now.

Printable Solar Panels

Australian researchers have recently developed a method of producing printable solar cells. A printer that has been installed at CSIRO is capable of printing solar cells in A3 size – the largest ever created. Although they are not ready to be released to the public, the technology – and low cost of production – is a good sign of things to come.

Solar Power Farms

In August 2013, the University of Queensland announced that it had would be leading a $450 million solar farm project in western New South Wales. A joint initiative between the Federal Government and AGL Energy, the project will see the building of the southern hemisphere’s largest solar power plant, bringing renewable energy into many more homes. (UQ, 2013)

The building of solar farms has the benefit of providing mass solar power and minimising our carbon footprint, without the need for individual homes to have solar panels installed.

Mildura Solar Concentration Power Station

The largest step towards increasing solar energy in the state of Victoria is due to be completed in 2017. The Mildura Solar Concentration Power Station, which will become Australia’s largest concentrated solar panel plant on completion, is set to be a 100MW power plant and currently has 40 CPV dishes already feeding power into the region’s grid. The technology to be used at the power station was originally developed by Boeing to be used on satellites.

The company who owns the power station, Silex, has said that the cost of energy could drop to 10c/kWh ($100/MWh) within a few years using their innovative technology, which – if achieved – is a significant decrease. (Renew Economy, 2013)

Conclusion

Considering the huge increase in uptake of solar energy in just the past five years, solar is clearly the way forward for Australia’s energy supplies. Not only is it cost-effective but it utilises a resource that is naturally available to us and doesn’t require Earth-destroying mining or drilling to get to it.

Although solar power is already a relatively significant part of energy in Australia, technology still has a long way to come before it is considered our primary source.

Images by Kenny Louie, Jimmy Joe and Richard Gifford.

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Weekly Science Picks

Markus — Sun, 15 Dec 2013 00:12:55 +0000

It is with a heavy heart that I must say, this is my final set of Weekly Science Picks here on Australian Science. In fact, it’s to be the final set of Weekly Science Picks. Unfortunately, running a site like this one is a costly affair, and it’s been an honour to be a writer here over the past year and a half. Scientific progress will, of course, always carry on and I hope there will always be places to discuss new findings, implications, and effects of it on human culture and society.

So, proudly then, here are the final set of news stories which caught my eye this week. Make no mistake – there’s been some pretty cool news recently!

Firstly, and in my opinion most excitingly, is a medical breakthrough which could actually revolutionise surgery in the future. And anyone who knows me will know that I don’t use words like “revolutionise” lightly. Quite simply, the device is a small pen, developed by the Australian Research Council Centre of Excellence for Electromaterials Science (ACES), which will be able to deposit stem cells and growth factors directly into injuries. This means that this pen could help injured tissue – bones, muscle, and even nerves – to regrow. Oh, and did I mention it works using 3D printing technology?

BioPen to rewrite orthopaedic implants surgery

The BioPen prototype was designed and built using the 3D printing equipment in the labs at the University of Wollongong and was this week handed over to clinical partners at St Vincent’s Hospital Melbourne, led by Professor Peter Choong, who will work on optimising the cell material for use in clinical trials.

For a long time humans were considered unique in that we use tools where other animal species don’t. But since that old idea, more and more animals – from birds to octopodes – have been shown to use tools in their daily lives. The most recent addition to this collection of smart creatures is the crocodile which has been found to use lures while hunting. Perhaps this might help show that reptiles are smarter than we give them credit for!

Alligators and Crocodiles Use Tools to Hunt, in a First

Relatively less is known about crocodiles and alligators than many animals, because, as large predators, they are difficult to raise in the lab and study up close in the wild. Their cold-bloodedness also makes them slow. “They operate on a different time scale; they do things more slowly,” Burghardt said. “Sometimes we don’t have the patience to let them strut their stuff, as it were … so this kind of study is important.”

A huge plume of water has been spotted, gushing from the surface of Enceladus, Saturn’s tiny snowball moon. While the exact source of Enceladus’ warmth is still something of a mystery, this sighting means that its activity is quite clear – this water plume is reaching an altitude of around 201 km above the surface of the tiny world. That’s nearly ten times as high as Olympus Mons, the solar system’s largest mountain (which itself dwarfs Everest, the heighest mountain on Earth).

Hubble Space Telescope Sees Evidence of Water Vapor Venting off Jupiter Moon

“By far the simplest explanation for this water vapor is that it erupted from plumes on the surface of Europa,

Cite this article:
Hammonds M (2013-12-15 00:12:55). Weekly Science Picks. Australian Science. Retrieved: May 01, 2024, from http://australianscience.com.au/news/weekly-science-picks-58/
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Could Australian Terrain Help Train Future Mars Explorers?

Elizabeth Howell — Mon, 08 Jul 2013 00:01:32 +0000

Researchers simulate Mars exploration during a 2008 NASA Desert RATS (Research and Technology Studies) exercise in Arizona. Credit: NASA

How do you rehearse for a Martian space trip? Simulations can only bring astronauts so far when they’re figuring out a mission. A typical person training for the International Space Station can expect a combination of classroom work, spacewalk rehearsals in the water, and robotic arm training using articles that are very close to the real deal.

Exploring another world is a complex problem yet again. Astronauts in the Apollo mission received hundreds of hours in geology training, for example, and flew to areas ranging from Meteor Crater in Arizona to the site of a huge crater in Sudbury, Ont. Today, NASA and other research institutions carry out Mars mission research at two Mars Society sites in Canada and Utah, among other locations.

Turns out Australia’s challenging environment could also be a good analog for the Red Planet. The Great Artesian Basin, which stretches across much of the east side of the continent, is the site of “acidic weathering” that could be similar to what was experienced on Mars, a new study says. Perhaps future Martian trainees could add Australia to their list of destinations.

A map of the Great Artesian Basin. Credit: Wikimedia Commons

The tough environment has an economic link to Australia: precious opals, the national gemstone of the country. The May 2013 paper in the Australian Journal of Earth Sciences suggests not only a way that opals form.

There’s a bit of a mystery behind opal formation, which Markus Hammonds documented in a past Australian Science article. Also, their formation could point to similarities to the Red Planet.

“Interestingly, acidic oxidative weathering has been documented at the surface of Mars, which shares an intriguing set of attributes with the Great Artesian Basin,” stated the scientific paper.

These characteristics include sandstones that appear very similar between the locations, a “drying out” period that created clay and opaline silica, and even a similar red color, the paper noted. The opals themselves were formed after the acidic weathering dried out the landscape amid the Eromanga Sea receding about 100 million years ago.

A sample of precious opal. Credit: Wikimedia Commons

So what are the implications of this link between Australia and Mars?

It could help us better understand geological features. Rovers on Mars keep stumbling across evidence of minerals that formed in water, “including opal-bearing mineral assemblages”, the paper noted. Research on the Red Planet is thus helping us to better understand how opal formed in Australia, it added, and how the area was dehydrated during the Late Cretaceous.

It could teach us more about each planet’s history. Both areas are very red, suggesting that “oxidative weathering played an important role during and after the dehydration of Mars’ surface”, the paper stated. From a wider perspective, comparative planetology between Mars and Earth could help us understand how a planet can lose much of its atmosphere (as Mars did) or hang on to it (as Earth has, so far.)

Australia could be a good training ground for budding Martian scientists. This finding has already generated a lot of interest in the greater space community (it was picked up by a NASA astrobiology publication, for example) and will likely bring about more research into the links. This could potentially bring Australia to more prominence as a potential training ground for Mars exploration. Geologists could train for searching on Mars by searching in the Great Artesian Basin.

Human Mars exploration is likely still years away, but at the very least, Australia could be a spot where technology is tested out and Martian geological exploration is simulated. The Mars Society has talked about putting in a “Mars-OZ” base in Australia, for example.

There are substantial risks to the journey — this Australian Science article by Sharon Harnett explains more about the hazards associated with radiation and cardiovascular damage, among other risks. There’s a lot we need to figure out. But as more findings like this recent one are released, interest in Australia as an analog environment is bound to increase.

Cite this article:
Howell E (2013-07-08 00:01:32). Could Australian Terrain Help Train Future Mars Explorers?. Australian Science. Retrieved: May 01, 2024, from http://australianscience.com.au/space/could-australian-terrain-help-train-future-mars-explorers/
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Quantum computing: Australian researchers store data on a single atom!

Markus — Thu, 16 May 2013 07:10:32 +0000

Computers are everywhere these days. They play us music, tell us when to wake up, remind us that we’re late for an appointment, and provide us with entertainment. Even if we don’t realise it, so ingrained in our lives are computers that the world would be a very different place without them. Computing is also an incredibly fast moving field of technology, and research is finally taking us towards the exciting world of quantum computing!

Quantum computers will work using quantum bits, or qubits for short, which are analogous to the digital bits used in computers like the one which you’re using to read this article. Recently, a team of engineers at the University of New South Wales (UNSW) has successfully demonstrated, for the first time ever, how a single atom can be act as a qubit, effectively showing the first step in building an ultra fast quantum computer. And they might just have created the best qubit ever made.

A quantum computer is, simply, a computer which makes use of quantum mechanical phenomena to perform calculations. Well, I say “simply”… Let’s step back a moment. The simplest form of computers involve actual moving objects, and using the positions of those objects to perform calculations. This is essentially how an abacus works, if you’ve ever used one. The earliest computers to be designed, automated this process, using mechanisms. Charles Babbage’s famous, albeit never built, Analytical Engine worked on exactly this basic principle, and if it had been constructed it would have truly been the world’s first computer.

Essentially, the way these old mechanical computers work is to use the positions of their mechanical parts to perform mathematical and logic functions. This is actually the fundamental way in which all computers work. Since the discovery of electricity and the invention of electronics, computers have worked using electric circuits – effectively using the position of electrons instead of the position of actual moving parts. As technology has progressed, computers have become faster, smaller, and more reliable, until the world around us today.

In modern electronics, silicon is king. Silicon-based electronics are the standard used everywhere, though they’re reaching the limit of what they’re capable of. For the next generation of electronics, some people are beginning to advocate new materials, such as graphene, over silicon. But ultimately, others have a higher goal. Proponents of quantum computing believe that in the future, the most vital components of computers will not be electronics at all, but single atoms.

In quantum mechanics, any single particle, from an electron to an atomic nucleus, has a set of properties which can often be changed quite easily. Where past computers used motion of mechanical parts and modern computers use motion of electrons, quantum computers will use changes in the properties of these particles to perform their calculations.

One such quantum property is known as spin (the same property behind magnetism), and this is what the UNSW engineers managed to manipulate. They based their qubit on a single silicon atom and demonstrated how they used changes in the nuclear spin of the nucleus to store and retrieve information. Andrea Morello at UNSW’s School of Electrical Engineering and Telecommunications described how; “We have adapted magnetic resonance technology, commonly known for its application in chemical analysis and MRI scans, to control and read-out the nuclear spin of a single atom in real time.

Cite this article:
Hammonds M (2013-05-16 07:10:32). Quantum computing: Australian researchers store data on a single atom!. Australian Science. Retrieved: May 01, 2024, from http://australianscience.com.au/technology/quantum-computing-australian-researchers-store-data-on-a-single-atom/
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Seriously, NAPLAN to include Science?

Danielle Spencer — Thu, 02 May 2013 00:09:23 +0000

In the last few weeks in Australian politics there have been critical discussions regarding the inclusion of science in NAPLAN (the National Assessment Program in Literacy and Numeracy). Without entering too much into the debate regarding the reported advantages or disadvantages of NAPLAN, it is heartening to hear that science is at the forefront of political agenda.

NAPLAN is a series of standardised testing given to all Australian students in Grades 3, 5, 7 and 9. Beginning in 2008, these pencil/pen and paper tests assess children in set skills relating to reading, language conventions, writing and numeracy. ACARA, Australian Curriculum Assessment and Reporting Authority, claim that “NAPLAN tests identify whether all students have the literacy and numeracy skills that provide the critical foundation for their learning, and for their productive and rewarding participation in the community

Cite this article:
Spencer D (2013-05-02 00:09:23). Seriously, NAPLAN to include Science? . Australian Science. Retrieved: May 01, 2024, from http://australianscience.com.au/education/seriously-naplan-to-include-science/
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A Supernova Post-Mortem in Radio Waves

Markus — Tue, 09 Apr 2013 00:09:43 +0000

It was a late February night in 1987 when, standing on top of a Chilean mountain range, Ian Shelton saw something which no one had seen for centuries. Looking up in disbelief, he watched a star explode some 160 thousand light years away. Rushing to another observatory to check with someone else, he was initially met with stark disbelief. But there was no doubt. Shelton had seen a supernova explosion with his own eyes.

Named SN 1987A, this was the death of a massive star in the Tarantula nebula. Distant enough to not even be in our own galaxy, but in the Large Magellanic Cloud – one of the Milky Way’s smaller satellite galaxies, the discovery was reported independently by Albert Jones in New Zealand. This began decades of fascinating observations for astronomers, as many began to watch this supernova expand over the years, in real time.

Supernova which are close enough to see with the naked eye are rare beasts. This was, and still is, the only one close enough and visible enough to see properly with modern telescopes, giving us some of the best information we’ve ever had about how an exploding supernova interacts with the dusty interstellar clouds which surround it.

The latest observations of this literally awesome event come courtesy of a team of astronomers working in Australia and Hong Kong, led by Giovanna Zanardo at the International Centre for Radio Astronomy Research (ICRAR). Using CSIRO’s Australia Telescope Compact Array in New South Wales, the researchers have published the highest resolution images of the stellar explosion’s aftermath ever taken.

Portrait of a Dying Star

High resolution images are wonderful in astronomy. The higher the resolution, the more you can learn about what you’re seeing. Zanardo and her colleages compared their observations with other images and data taken at optical and x-ray wavelengths. On doing so, they gained some fresh insight into exactly what happens shortly after a star explodes.

In the centre of the explosion, stellar ground zero, they discovered a pulsar wind nebula. This is a pocket of intensely hot material emitted by a neutron star*, the last remains of the exploding star’s core, proving that SN 1987A did not create a black hole.

Referred to in technical jargon as a “compact source”, a neutron star is a tiny ball of incredibly dense material. With a mass up to over 3 times the mass of the Sun, these bizarre little objects truly are compact. An average neutron star has a radius of just 12 km, which is comparable with the size of Sydney. Yes, you read that correctly. The mass of a star compressed into something with a size similar to a large city.

This discovery actually answers a long standing puzzle about SN 1987 A. Supernovae like SN 1987A are normally expected to form neutron stars, because of the near-unimaginable pressures which occur inside an exploding star. But for several years, despite looking carefully, no astronomers could find any trace of a neutron star amid the stellar debris. But the star which caused this supernova would not have been massive enough to collapse into a black hole, leading theoreticians to try and devise explanations for why there was no neutron star to be seen.

If Zanardo’s team are right, and they have indeed found a pulsar wind nebula inside the shattered remnants of this dead star, then it has to be generated by something. Unless I’m mistaken, this may be some of the most convincing evidence yet for the missing neutron star!

Seeing Clearly in Invisible Light

Discovering all of this, however, was far from easy. Radio images at centimetre wavelengths are difficult to capture with detail. Exceptionally good weather conditions are needed. Zanardo explains, “For this telescope, these [observations] are usually only possible during cooler winter conditions, but even then the humidity and low elevation of the site makes things very challenging.

Cite this article:
Hammonds M (2013-04-09 00:09:43). A Supernova Post-Mortem in Radio Waves. Australian Science. Retrieved: May 01, 2024, from http://australianscience.com.au/physics/a-supernova-post-mortem-in-radio-waves/
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The Carbon Footprint of Australian Migrations

Editorial Board — Fri, 15 Mar 2013 10:20:20 +0000

Measuring the impact of Australian migration on the Australian carbon footprint is a difficult task because of the complexity of the factors involved. However, a direct cause and effect relationship between the two exists, and it is related partially to population growth due to overseas migration, as well as to rural-urban migrations. Both of which are the consequence of the modernisation and urbanisation of Australian society. This article will present data and research findings about some of the factors that need to be taken into account when discussing the issue of the Australian greenhouse gas emissions. In conclusion it will also share some insights into some of the ways in which the Australian carbon footprint can be reduced.

Rural-Urban Migration

Australia is increasingly becoming an urbanised nation and the scope of migrations from rural to urban areas has recently been growing. A typically higher standard of living in urban areas, industrial development, the built environment and technological advancement; all have a considerable impact on the environment. With urbanisation, the consumption pattern in Australia is changing, and there is a significant increase in consumption per capita.

Recently, there has been more research on how population growth and internal migration into urban areas affect the environment. Australian households are directly responsible for about 20 percent of total carbon pollution. The increasing production of consumer goods has a major impact on the environment – there is an increase of carbon dioxide emissions, or greenhouse gas (GHG) emissions, which is considered the main cause of global warming. Consumption per capita is greater in urban than in rural areas. Greater volumes of transport and removals also have their share in the increase of the carbon footprint. The increase in waste streams resulting from greater consumption causes an amplification of emissions from landfill facilities, which currently emit about 15 million tonnes of carbon pollution per year.[1]

One of the ways to analyse household greenhouse gas expenditure is to break down how much energy consumption and greenhouse gas emissions a human being requires for different needs and aspects of living (such as food or mobility). According to Dr Manfred Lenzen, Professor of Sustainability Research at Integrated Sustainability Analysis (ISA) at the University of Sydney, the analysis of energy and greenhouse gas requirements of different stages in the economy is a better way to structure the data which needs to be considered when creating policies related to the reduction of the carbon footprint.[2]

Energy consumption in Australia 1975–2000 (Australian Bureau of Agricultural and
Resource Economics 2006)*

Professor Lenzen explained to us that the main advantage of the input-output method is that it includes a complete picture of a household’s GHG responsibility. In some information material from Professor Lenzen’s studies we see that the focus is on switching lights off, having shorter showers, or driving less. But what about our shopping habits? How much emissions were caused because of that T-shirt I just bought, or that flat-screen TV, or that surfboard, or that movie ticket, or that insurance policy? Such things are actually two thirds of the story and must not be ignored. Because if they were, policy would not be as effective as it could be. When it comes to the difference between the consumption-related carbon emissions of households in urban and in rural areas, people in the inner city drive less, so they have some advantages there. However people in rural households usually earn, and therefore spend less, which ultimately is a stronger effect, and therefore rural households cause (generally speaking) less GHG emissions.[3]

The increased need for residential space is another large contributor to carbon pollution through the construction industry and the disposal of demolition waste. Investments into energy efficient homes and appliances provide a partial solution to this problem. According to Professor Dr Deo Prasad, Director of the UNSW Centre for a Sustainable Built Environment, most of the potential low cost greenhouse gas emissions saving opportunities are known to be in the built environment – anywhere between 40-70%, depending on which report and boundary conditions they relate to. However, past experience suggests that market failure/barriers will prevent uptake of these opportunities, even with a price on carbon. In December last year Professor Prasad was one of the experts who launched the Low Carbon Living CRC, which brings together key property, planning, engineering and policy organisations with leading Australian researchers. Their focus was to develop new social, technological and policy tools for reducing greenhouse gas emissions in the built environment. The CRC will help unlock barriers to cost-effective carbon reduction opportunities, empower communities and facilitate the widespread adoption of integrated renewable energy. This will enable the sector to transition and contribute to Australia’s greenhouse gas emissions targets while maintaining industry competitiveness and improving quality of life.[4]

If we look at overall CO2 emissions of countries, according to the 2012 report on trends in global CO2 emissions by the PBL Netherlands Environmental Assessment Agency, Australia is the 16^th biggest polluter in the world. However, if we look at CO2 emissions per capita, Australia has earned the unflattering title of the biggest polluter on the planet in 2009, when it replaced the U.S. in the first position with 18.3 tonnes of CO2 emissions per capita. In 2011, while the U.S. CO2 emission levels per capita decreased by 2 percent; Australia’s emissions rose by 3 percent.

Dr David Stern, Professor at the Australian National University and research associate at the Centre for Climate Economics and Policy, discusses his research findings; taking into account the differences between Australia and other countries in terms of the climate, and the type of industries we have – for example, we need less heating but the mining industry is very energy intensive – and other factors, Australia is relatively energy inefficient compared to other developed countries and progress on improving energy efficiency has been quite slow.[5]

There is probably a lot of scope for improving energy efficiency on the consumer side of the economy – energy efficiency of houses, water heating etc. The rebound effect where savings in energy costs are used to spend on other energy using goods and services is more limited for consumers than for industry, and so the gains could be substantial without a lot of take back. Of course, reduced energy use reduces carbon emissions. The Australian government’s carbon price will probably have some effect on this but better information, building codes etc. can help. We have the Energy Efficiency Rating (EER) system for houses for example, but do people know what it means?[6]

Professor Stern also points out that the biggest impact of immigration is going to be that immigrants are generally coming from countries with lower carbon emissions per capita than Australia. The fraction of immigrants coming from the US, Canada, Qatar etc. is small, though there are some. So, when immigrants move to Australia they will increase their emissions on average and that will increase global emissions.

Even though population growth is often quoted as one of the main reasons for the increase in Australia’s CO2 emissions, Australian society and economy are continually evolving and new technologies which contribute to sustainability are being developed on a constant basis. Therefore it is difficult if not impossible to calculate the optimal urban population growth of Australia. Greater sustainability can be achieved mainly through the regulation of urban development and consumption patterns in urban areas – these are the two factors that the government can easily influence both through direct and indirect measures. Urban planning additionally decreases the average commuting time, which is also a significant polluting factor.

Overseas Migration

More than one-fifth, i.e. 23 percent of Australians were born overseas. The majority of immigrants choose to settle in major cities – according to the 2006 Census, 82 percent of overseas-born Australian residents live in major urban areas. In comparison, only 61 percent of Australia-born citizens live in urban areas.[7] Since most migrants move into urban areas, they tend to adopt average urban Australian consumption patterns.

Net overseas migration (NOM) is the difference between the number of people leaving Australia and arriving to Australia in the long term. The influence of NOM on greenhouse gas emissions has been researched, and here are some projections of how NOM will influence air pollution in Australia in the future based on research conducted by the Australian Government Department of Immigration and Citizenship summarized in “Long-term physical implications of net overseas migration: Australia in 2050

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Asteroids, extinctions, and biodiversity: Wiping the slate clean for new life to flourish

Markus — Fri, 08 Mar 2013 00:24:56 +0000

The recent meteor strike in Russia has been a rather sobering reminder that Earth has been regularly battered during its history, by space rocks. Actually, the amount of meteoritic material constantly landing on Earth is startling – on average, over 100 tons every day which we don’t even notice. Now, most of that is in the form of tiny rock fragments and dust; with most being small enough to be vapourised as they burn up in Earth’s atmosphere, relatively few meteorites ever end up on the ground. The part which may make us uneasy, however, is the fact that occasionally something larger crosses Earth’s path. Something much larger.

We already know with some degree of certainty that a gigantic asteroid impact may have played a role in wiping the dinosaurs off the face of our world, and we also know it’s not the only such large impact in Earth’s history. Now there’s evidence of another huge impact – and this one was in Australia!

With a diameter spanning around 200 km in South Australia’s East Warbuton basin, an ancient impact site has been uncovered. Created by an asteroid which was probably between 10-20 km in diamater, affecting an area of terrain of around 30,000 km, this impact zone is the third largest currently known. When this particular asteroid struck Earth some 360 million years ago, its effects would have been profound and global.

Andrew Glikson, a visiting fellow at the Australian National University, first started investigating the area after hearing about structural abnormalities in the rocks there. He spent time in a crystallography lab, studying the orientation of crystals in rocks collected from the site, and found that the most likely cause for what he was seeing was the result of the rocks being subjected to a huge shock. Given the extent and area of the shocked rocks, the most likely explanation is a giant extraterrestrial impact.

The most well known giant impact, known as the Chicxulub Impact Event, occurred about 66 million years ago causing the Cretaceous-Tertiary extinction event, and quite probably being the final nail in the coffin of the dinosaurs. This newly discovered Australian impact site, however, is much older. In fact, when this asteroid struck Earth, it was around 100 million years before any dinosaurs had even evolved. In fact, it would have likely been during the Carboniferous Period in Earth’s geologic history. Interestingly enough, there was a minor extinction event during the Carboniferous. A minor extinction caused by a change in Earth’s climate.

Glikson went on to explain that this impact was likely one of part of a cluster which caused a number of impacts around that time. This cluster of impacts was very likely behind an extinction event. Simply, a huge impact like the one discovered in the middle of Australia would cause devastation. The effects locally would be severe, splattering molten rock into the air which would then rain back down to the ground hundreds of kilometres away, and a blast wave of superheated air would cause widespread forest fires near the impact zone – particularly in the oxygen rich atmosphere of Earth’s Carboniferous forests.

The global repercussions of such an impact, however, would be much worse. A huge amount of dust would be thrown up into Earth’s atmosphere, choking out the sunlight. This would cause Earth’s surface to cool, and the reduced light would make plants die off. A big enough impact – or a series of them – would throw enough dust into the skies that this could happen on a global scale. With the food chain cut off at the plants which are its source, a mass extinction would follow as animals would have trouble finding food to survive on.

These events are mercifully rare. A giant impact may happen on Earth once every ten million years or so. Interestingly enough though, researchers in a different study have found evidence that extinction events on planet Earth may actually be beneficial to biodiversity.

Kale Sniderman, part of a group of researchers working at the University of Melbourne and the University of Tasmania, focussed on an event much more recent than the East Warburton impact. Instead, he and the others looked at the last ice age, around one million years ago and together they constructed a hypothesis that extinction events may be even more important for biodiversity than rapid evolution. While their work concerns species which went extinct during ice ages as opposed to impact events, a suitably large meteor strike may be a factor in what causes an ice age to begin.

The traditional view of most biologists is that some areas have greater biodiversity due to evolution in those places progressing more rapidly. Evolution has always been the only thing emphasised in biodiversity studies, but Sniderman and his colleagues have taken the first step in overturning this picture.

Their work looked at regions in South Africa and Australia – notable as two of the most diverse areas on planet Earth. South Western Australia is known among botanists for having a huge variety of plants, particularly tough leaved shrubs and trees. The very tip of the South African cape is even more diverse, populated by very similar types of plant. For a long time, biologists have theorised that the diversty in these rather similar areas was down to the dry, arid summer conditions and the nutrient poor soils in these areas. The exact connection, however, has never been entirely apparent.

As it happens, the status may not be quite so quo here. Studying fossils from an ancient lake in South Eastern Australia, it was found that plant life in Australia tended to die off as the continent has gradually become drier – a process taking millions of years. In particular, during the last ice age, a huge amount of rainforest plants died off. This allowed other hardier plants to fill the space they’d left and plant diversity expanded as they did so – creating what was described by University of Tasmania’s Greg Jordan as “a remarkable number of tough-leaved, shrubby plants.” Thinking about this process logically, it seems to make perfect sense. In any place on Earth where there’s a vacant ecological niche, life will typically evolve to try and fill that niche. Where an extinction occurs, a huge niche will suddenly become empty. This would prompt a veritable explosion of new life forms to fill in the gap.

This study not only gives new insight into how extinction events can affect diversity of life forms, but also has implications for current and future climate change, and how species may be able to cope with it. As I mentioned previously when talking about the Great Barrier Reef, Australian wildlife is already suffering from climate change. However, at least for plant life on land, there’s a good chance that the species most easily affected by rapid environmental changes may have already died off during the last ice age.

To loop this discussion back to the beginning, if an extinction due to an ice age could help to boost biodiversity, logically an extinction due to an asteroid impact event could do the same. To my knowledge, there are no studies in this context concerning what happened to biodiversity after the Chicxulub impact event (though I’ll admit that I may be wrong on this), but it would be very interesting to see what such studies might find. Similarly, it would be interesting to know if any such flourishes of biodiversity occurred after the newly discovered East Warbuton impact too. It could be that only certain types of extinction event can boost diversity of life on a planet. That said, if the same thing can occur after an asteroid impact then it may have implications reaching beyond Earth.

If a giant impact event could serve to actually boost life on a planetary scale, then it may imply that once life has taken hold on a planet, it’s more robust than we’ve been giving it credit for. The implications for astrobiologists and the search for life elsewhere in the galaxy are quite clear.

To end on an aside, a large enough asteroid strike even on Earth today would cause widespread fires kilometres away from the impact site. Back in the Carboniferous Period, around the time when the East Warbuton impact occurred, the situation would have been much more dramatic; the oxygen content of Earth’s atmosphere was up to 15% higher then, than it is today. In such a combustible atmosphere, where fires could have been started by a simple lightning strike, a large asteroid impact could cause a widespread inferno. However, South Africa (one of the places considered in the biodiversity study) is home to a number of species which have evolved specifically to survive fires. In particular, the highly diverse Fynbos region is known for a number of plants for which fire is actually an integral part of their lifecycle. Some seeds belonging to protea species simply don’t germinate unless they’re exposed to the intense heat of a wildfire. Provided they could gather sufficient amounts of sunlight under the darkened skies, plants like these may be able to rapidly repopulate an area after an impact event.

Life on Earth, evidently, has resilience which can still surprise us.

Image credits:
Top – Artists impression of a large scale impact event – Don Davis/NASA
Upper Middle – Australia seen from orbit – NASA
Lower Middle – League Scrub sub tropical rainforest, near Bowraville NSW, Australia – Peter Woodard/Wikimedia Commons
Bottom – Garden – https://croatia-real.estate

Cite this article:
Hammonds M (2013-03-08 00:24:56). Asteroids, extinctions, and biodiversity: Wiping the slate clean for new life to flourish. Australian Science. Retrieved: May 01, 2024, from http://australianscience.com.au/environmental-science/asteroids-extinctions-and-biodiversity-wiping-the-slate-clean-for-new-life-to-flourish/
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Ediacara: a “failed” evolutionary experiment?

Kevin Orrman-Rossiter — Tue, 12 Feb 2013 00:11:36 +0000

The Ediacara Hills, north of the city of Adelaide in South Australia are a tumbling mass of ancient rocks. Sunbaked now, 580 million years ago they were a sea alive with soft-bodied organisms. These organisms varied greatly: from millimetres to metres in size; from “blob-like” to intricate in complexity; and from sturdy and resistant to a jelly-soft rigidity. They are all prosaically named the Ediacaran biota. A mundane name for what are the earliest known multicellular organisms on Earth.

Turning over rocks and finding fossils

In 1946, an Australian mining geologist named Reginald Sprigg was inspecting abandoned mines the Ediacara Hills. These hills take their name from the aboriginal Idiyakra, “water is present”. Serendipitously, while eating his lunch, Sprigg found fossilized imprints of soft-bodied organisms on the undersides of slabs of quartzite and sandstone. Most were round, disc-shaped forms that Sprigg dubbed “medusoids” from their seeming similarity to jellyfish. Others, however, resembled worms, arthropods, or even stranger things; quilted mattresses and mud-filled bags.

Reginald Sprigg. Photo credit: Wiki commons.

Sprigg thought that these fossils were ancient and dating from the Cambrian era (541-485 million years ago). He submitted a paper to the journal Nature, but it was refused. Sprigg travelled to London and presented his findings to the 1948 International Geological Congress, but failed to excite either interest or belief.

A time-coil of the Earth’s ages from formation to the present age. Adapted from Press and Siever (2000) Understanding the Earth.

These were not the first Precambrian soft-bodied fossils to be found and described — scattered reports of them had appeared in the scientific literature as far back as the mid-nineteenth century.

The first Ediacaran fossils discovered were the disc-shaped Aspidella terranovica in 1868. Their discoverer, Scottish geological surveyor Alexander Murray, found them to lay below the the Cambrian strata that were then thought to contain the very first signs of life. It took a further four years for anybody to dare propose they could be fossils. Elkanah Billings‘ 1872 proposal was dismissed by his peers on account of their simple form. They were instead declared gas escape structures, inorganic concretions, or even tricks played by a malicious God to promote unbelief.

Aspidella. Image source Wikipedia.

This one-sided debate soon fell into obscurity as no similar structures elsewhere in the world were then known. In 1933, Georg Gürich discovered specimens in Namibia. They were assigned to the Cambrian Period by the firm belief that life originated in the Cambrian, and no link to Aspidella was made.

It was not until the 1957 British discovery of the frond-shaped fossil Charnia in England’s Charnwood Forest that the pre-Cambrian was seriously considered as containing life. Due to the detailed geological mapping of the British Geological Survey there was no doubt that these fossils sat in Precambrian rocks.

The iconic Ediacaran Charnia. Image source Wikipedia.

University of Adelaide palæontologist Martin Glaessner finally, in 1959, made the connection between this and the earlier finds. With a combination of improved dating of existing specimens and an injection of vigour into the search many more fossils were recognised.

The naming the “Ediacaran” period

Due to this punctuated discovery a plethora of different names existed for this pre-Cambrian period and its biota. In 1960 the French name “Ediacarien” was added to the competing terms “Sinian” and “Vendian” for late-Precambrian rocks, and these names were also applied to the life-forms. “Ediacaran” and “Ediacarian” were subsequently applied to the epoch or period of geological time and its corresponding rocks. In March 2004, the International Union of Geological Sciences ended the inconsistency by formally naming the terminal period of the Neoproterozoic after the Australian locality.

The rise of the soft-bodied Ediacaran

It took almost 4 billion years from the formation of the Earth for the Ediacaran organisms to first appear, 655 million years ago. Fossils of single-cell organisms are reported from an age 3,460 million years ago. The first uncontroversial evidence for life though is found 2,700 million years ago. Cells with nuclei certainly existed by 1,200 million years ago.

The reason why it took so long for forms with an Ediacaran grade of organisation to appear is uncertain. A primary size-limiting factor is the amount of atmospheric oxygen. With the low oxygen levels in the early Earth, as low as 0.1% of today’s levels, organisms had to be simple. The oxygen cannot reach the centre of a complex organism quickly enough to supply its metabolic demand. So without sufficient oxygen life could only be very simple.

On the early Earth, reactive elements such as iron and uranium existed in a reduced form, which would react with any free oxygen produced by photosynthesising organisms. Oxygen would not be able to build up in the atmosphere until all the iron had rusted and other reactive elements had also been oxidised.

Banded ironstone, sedimentary oxidised iron. Image source Wikipedia.

Periods of intense cold have also been suggested as a barrier to the evolution of multicellular life. The period preceeding the Ediacaran is known as the Cryogenian. The greatest ice ages known to have occurred on Earth, possibly covering the entire planet, occurred during this period. These ‘snowball earth‘ events are still the subject of much scientific controversy, whether these glaciations were truly global or merely localised events. The diversity of life in modern Antarctica has also sparked disagreement over whether cold temperatures increase or decrease the rate of evolution.

Antarctica snow dome. Image source Wikipedia.

Oxygen, is still seen as key to enable cells to cluster and differentiate. It seems to have accumulated in two pulses; the rise of small, sessile (stationary) organisms seems to correlate with an early oxygenation event, with larger and mobile organisms appearing around the second pulse of oxygenation – the rise of the Endiacaran.

Life, but not exactly as we know it

The advantages of multicellularity include increased size and specialisation, physical protection and conditions for the development of complex behaviour. Unfortunately the soft-bodied physiology of the organisms have meant that fossil remains make their nature speculative and seem quite alien.

Microdictyon, fossil and artists impression. Image source Wikipedia.

While some can be likened to modern jellyfish, corals and lichens, many others remain more enigmatic. For example the Charnia are lacking any mouth, gut, reproductive organs, or indeed any evidence of internal anatomy, their lifestyle was somewhat peculiar by modern standards; the most widely accepted hypothesis holds that they sucked nutrients out of the surrounding seawater by osmosis.

The demise of the Ediacaran

The Cambrian period is marked by the appearance of organisms who evolved the ability to precipitate minerals used for skeletons and hard shells. Organisms which are more easily preserved as fossils than soft-bodied ones. This “Cambrian Explosion

Cite this article:
Orrman-Rossiter K (2013-02-12 00:11:36). Ediacara: a "failed" evolutionary experiment?. Australian Science. Retrieved: May 01, 2024, from http://australianscience.com.au/science-2/ediacara-a-failed-evolutionary-experiment/
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The post Ediacara: a “failed” evolutionary experiment? appeared first on Australian Science.

Rare echidna species not so extinct after all?

Markus — Thu, 07 Feb 2013 00:22:29 +0000

Speaking as a European, Australia has something of a reputation for having some rather unusual wildlife. Easily the most unusual are the small handful of monotreme species – the echidnas, and the duck-billed platypus. The only species of egg-laying mammals in the world today, these little creatures may once have been quite widespread. Now, however, they’re only found in Australia and New Guinea. One species in particular, the long-beaked echidna, is critically endangered. It was believed to have been extinct in Australia for over 30,000 years (and only found in New Guinea), since the last ice age. It was believed, that is, until recently. And the evidence for this rediscovery came from a rather surprising source.

100 years ago, biologists worked a lot differently to the way they do today. Back then, it was common practice to travel to remote places and collect specimens – by way of hunting animals, shooting them, and getting a taxidermist to stuff them. While this bloodthirsty pokemon attitude may seem ghastly to our modern sensibilities, it was once simply the way things were done, and many such specimens are still on display in museums. Though it should be added that such specimen collecting is widely outlawed today.

Nonetheless, one such specimen was found in London’s Natural History Museum. The creature had been “collected” in Australia in 1901, scientifically described, and had subsequently been stored and forgotten about entirely. I have to wonder what those researchers may have done if they’d realised the true significance of this unassuming little creature.

The fascinating thing is really that this little preserved creature is the keystone for the entire study. Just one single specimen. However, it was very well documented and most certainly came from Australia. Its discovery was quite serendipitous too, when zoologist Kristofer Helgen from the Smithsonian Institution, Washington, was paying a visit to the London Natural History Museum.

From the description it was tagged with, this echidna had been found on Mount Anderson, in sparsely populated Northwest Australia. Following up the find, researchers decided to investigate further. In West Kimberley, they spoke to some aboriginal communities where people recounted stories of how their parents used to hunt echidnas which were much larger than the others. Using photographs, they identified those large echidnas as the same long-beaked echidna species still found in New Guinea.

So the big question is, are long-beaked echidnas still found in Australia today? This discovery does give us some more information about how adaptable these spiny little animals are; long-beaked echidnas can evidently survive in both arid Australian scrub land and lush New Guinea rainforests. Until a living animal is found, it’s impossible to make any definite statements. And finding them is no easy task. They’re nocturnal creatures, and the known populations of them in New Guinea are difficult to find. All the same, conservationists can be hopeful that long-beaked echidnas may not be extinct in Australia just yet.

Cite this article:
Hammonds M (2013-02-07 00:22:29). Rare echidna species not so extinct after all?. Australian Science. Retrieved: May 01, 2024, from http://australianscience.com.au/biology/rare-echidna-species-not-so-extinct-after-all/
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