We sliced open radioactive particles from soil in South Australia and found they may be leaking plutonium

Barbara Etschmann, Monash University; Joel Brugger, Monash University, and Vanessa Wong, Monash UniversityAlmost 60 years after British nuclear tests ended, radioactive particles containing plutonium and uranium still contaminate the landscape around Maralinga in outback South Australia.

These “hot particles” are not as stable as we once assumed. Our research shows they are likely releasing tiny chunks of plutonium and uranium which can be easily transported in dust and water, inhaled by humans and wildlife and taken up by plants.

A British nuclear playground

After the US atomic bombings of Hiroshima and Nagasaki in 1945, other nations raced to build their own nuclear weapons. Britain was looking for locations to conduct its tests. When it approached the Australian government in the early 1950s, Australia was only too eager to agree.

Between 1952 and 1963, Britain detonated 12 nuclear bombs in Australia. There were three in the Montebello Islands off Western Australia, but most were in outback South Australia: two at Emu Field and seven at Maralinga.

British nuclear tests left behind a radioactive legacy.
National Archives of Australia

Besides the full-scale nuclear detonations, there were hundreds of “subcritical” trials designed to test the performance and safety of nuclear weapons and their components. These trials usually involved blowing up nuclear devices with conventional explosives, or setting them on fire.

The subcritical tests released radioactive materials. The Vixen B trials alone (at the Taranaki test site at Maralinga) spread 22.2 kilograms of plutonium and more than 40 kilograms of uranium across the arid landscape. For comparison, the nuclear bomb dropped on Nagasaki contained 6.4 kilograms of plutonium, while the one dropped on Hiroshima held 64 kilograms of uranium.

These tests resulted in long-lasting radioactive contamination of the environment. The full extent of the contamination was only realised in 1984, before the land was returned to its traditional owners, the Maralinga Tjarutja people.

Hot potatoes

Despite numerous cleanup efforts, residual plutonium and uranium remains at Maralinga. Most is present in the form of “hot particles”. These are tiny radioactive grains (much smaller than a millimetre) dispersed in the soil.

Plutonium is a radioactive element mostly made by humans, and the weapons-grade plutonium used in the British nuclear tests has a half life of 24,100 years. This means even 24,100 years after the Vixen B trials that ended in 1963, there will still be almost two Nagasaki bombs worth of plutonium spread around the Taranaki test site.

Plutonium emits alpha radiation that can damage DNA if it enters a body through eating, drinking or breathing.

In their original state, the plutonium and uranium particles are rather inactive. However, over time, when exposed to atmosphere, water, or microbes, they may weather and release plutonium and uranium in dust or rainstorms.

Until recently, we knew little about the internal makeup of these hot particles. This makes it very hard to accurately assess the environmental and health risks they pose.

Monash PhD student Megan Cook (the lead author on our new paper) took on this challenge. Her research aimed to identify how plutonium was deposited as it was carried by atmospheric currents following the nuclear tests (some of it travelled as far as Queensland!), the characteristics of the plutonium hot particles when they landed, and potential movement within the soil.

Nanotechnology to the rescue

Previous studies used the super intense X-rays generated by synchrotron light sources to map the distribution and oxidation state of plutonium inside the hot particles at the micrometre scale.

To get more detail, we used X-rays from the Diamond synchrotron near Oxford in the UK, a huge machine more than half a kilometre in circumference that produces light ten billion times brighter than the Sun in a particle accelerator.

Studying how the particles absorbed X-rays revealed they contained plutonium and uranium in several different states of oxidation – which affects how reactive and toxic they are. However, when we looked at the shadows the particles cast in X-ray light (or “X-ray diffraction”), we couldn’t interpret the results without knowing more about the different chemicals inside the particles.

To find out more, we used a machine at Monash University that can slice open tiny samples with a nanometre-wide beam of high-energy ions, then analyse the elements inside and make images of the interior. This is a bit like using a lightsaber to cut a rock, only at the tiniest of scales. This revealed in exquisite detail the complex array of materials and textures inside the particles.

Plutonium and uranium show up as bright lumps embedded in darker iron-aluminium alloy in this electron microscope image.
Cook et al (2021), Scientific Reports, Author provided

Much of the plutonium and uranium is distributed in tiny particles sized between a few micrometres and a few nanometres, or dissolved in iron-aluminium alloys. We also discovered a plutonium-uranium-carbon compound that would be destroyed quickly in the presence of air, but which was held stable by the metallic alloy.

This complex physical and chemical structure of the particles suggests the particles formed by the cooling of droplets of molten metal from the explosion cloud.

In the end, it took a multidisciplinary team across three continents — including soil scientists, mineralogists, physicists, mineral engineers, synchrotron scientists, microscopists, and radiochemists — to reveal the nature of the Maralinga hot particles.

From fire to dust

Our results suggest natural chemical and physical processes in the outback environment may cause the slow release of plutonium from the hot particles over the long term. This release of plutonium is likely to be contributing to ongoing uptake of plutonium by wildlife at Maralinga.

Even under the semi-arid conditions of Maralinga, the hot particles slowly break down, liberating their deadly cargo. The lessons from the Maralinga particles are not limited to outback Australia. They are also useful in understanding particles generated from dirty bombs or released during subcritical nuclear incidents.

There have been a few documented instances of such incidents. These include the B-52 accidents that resulted in the conventional detonation of thermonuclear weapons near Palomares in Spain in 1966, and Thule in Greenland in 1968, and the explosion of an armed nuclear missile and subsequent fire at the McGuire Air Force Base in the USA in 1960.

Thousands of active nuclear weapons are still held by nations around the world today. The Maralinga legacy shows the world can ill afford incidents involving nuclear particles.

Barbara Etschmann, Research officer, Monash University; Joel Brugger, Professor of Synchrotron Geosciences, Monash University, and Vanessa Wong, Associate Professor, Monash University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

This $1 billion energy deal promises to cut emissions and secure jobs. So why on earth is gas included?

Samantha Hepburn, Deakin UniversityIn case you missed it, a major A$1 billion energy deal between the Morrison and the South Australian government was revealed recently.

The bilateral deal represents a key driver for the national economic recovery from COVID. It promises to provide jobs in the energy sector and contribute to South Australia achieving net 100% renewables by 2030.

But there’s a big caveat: the agreement involves a joint commitment to accelerate new gas supplies into the east coast market.

With so much money on the table and other nations recently doubling down on climate commitments, let’s look at the good and bad bits of this landmark deal in more detail.

A gas-led economic recovery

The agreement was announced ahead of US President Joe Biden’s climate summit last week, which saw Australia spruik technology growth to cut emissions instead of committing to new climate targets.

In total, the federal government will contribute A$660 million and the South Australian government A$422 million towards the new deal.

Both governments have also agreed to a gas target of an additional 50 petajoules of energy per year by the end of 2023, and 80 petajoules by 2030. Their rationale is the need to improve energy security and reliability.

This focus on gas in the agreement stems from the federal government’s much-criticised, gas-led economic recovery plan, which argues new gas supplies are vital for future energy security.

In February, the Australian Competition and Consumer Commission outlined a potential shortfall of 30 petajoules of gas for the east-coast market leading up to 2024. This shortfall could impact energy supply, and the federal government has used this to help justify opening new gas reserves.

However, nothing is certain — COVID has reduced global demand for gas so any shortfall will likely be deferred. Meanwhile, renewable technology and hydrogen production and use are rapidly advancing.

Bad: investing in gas

With the seismic shift in the economics of renewables over the past decade, investing in new gas supply is unnecessary and retrograde. In fact, it’s now more expensive to transition from coal to gas than from coal to renewables.

For example, the cost of lithium ion batteries used for battery storage has fallen over the past decade by nearly 90%. But the cost of gas — both economically and environmentally — has steadily risen. This inevitably means means its role in the energy market will diminish.

Eventually, gas generators will be retired without replacement. Victoria’s March quarter data, for example, shows black coal generation volumes dropped by 9.5% and gas generation dropped by 43%. Meanwhile, rooftop solar went up 25%, utility solar up by 40% and wind power by 24%.

Solar farm in the desert at sunset — Up to $110 million will be spent on solar thermal and other storage projects in South Australia.
Shutterstock

And at the end of the day, gas is still a fossil fuel. There are approximately 22 major gas production and export projects proposed for Australia. A report from The Australia Institute in September 2020 suggested that, if produced, these projects could lead to about half a billion tonnes of emissions.

If all potential gas resources in Australia were tapped, the report indicates it could result in emissions equivalent to three times the current annual global emissions.

Good: investing in critical infrastructure

The energy deal sets aside $50 million towards the new $1.5 billion electricity interconnector between South Australia and NSW. This is critical infrastructure that will allow South Australia, Victoria and NSW to share energy reserves.

Indeed, the Australian Energy Market Operator has reported in excess of 5,000 megawatts of renewable energy projects near the proposed interconnector. This means South Australian wind and solar could contribute more significantly to electricity generation in both Victoria and NSW.

In turn, this will have a positive effect on pricing. Forecasts suggest the proposed new interconnector could reduce power bills by up to $66 a year in South Australia and $30 in NSW.

The energy deal also reserves funding for “investment priority areas”, which include carbon capture storage, electric vehicles and hydrogen. For example, $110 million is allocated for energy storage projects. This level of funding will help develop a world-class hydrogen export industry in South Australia.

The verdict

The energy deal is a funding win for renewable energy and technology, with energy technology advancing much faster than anticipated. However, its focus on gas is environmentally and economically regressive.

It’s completely inconsistent with the powerful climate plan announced by the Joe Biden administration at the Climate Summit last week, which includes a pause and review of oil and gas drilling on US federal land and doubling energy production from offshore windfarms by 2030.

In March, the European Union’s parliament voted in favour of a Carbon Border Adjustment Mechanism. This will impose a tariff on products being sold into the EU according to the amount of carbon involved in making them. The Biden administration in the US has announced a similar plan.

What’s more, the European Union and the US, as outlined at the recent Climate Summit, are planning to impose fees or quotas on goods from countries failing to meet their climate and environmental obligations. This may mean Australian manufacturers will end up paying for the governments failure to take rapid action to drive down emissions.

Bilateral agreements provide critical planning and funding for Australia’s energy progression. However, they should not prolong the use of fossil fuels under the guise of energy security. To do so undermines global climate change imperatives and hinders Australia’s progress in a new energy era.

Samantha Hepburn, Director of the Centre for Energy and Natural Resources Law, Deakin Law School, Deakin University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

There’s a long and devastating history behind the proposal for a nuclear waste dump in South Australia

Rosemary Laing, one dozen considerations, Totem 1, Emu (2013) on display at The Image is Not Nothing.
Josh Geelen

Katherine Aigner, Australian National UniversityOn Saturday the Adelaide Festival hosted a public showing of Australian Atomic Confessions, a documentary I co-directed about the tragic and long-lasting effects of the atomic weapons testing carried out by Britain in South Australia in the 1950s.

Amid works from 20 artists reflecting on nuclear trauma as experienced by Indigenous peoples, the discussion that followed brought up the ways in which attempts at nuclear colonisation have continued in South Australia, and are continuing right now.

For the fourth time in 23 years South Australia is being targeted for a nuclear waste dump — this time at Napandee, a property near Kimba on the Eyre Peninsula.

The plan is likely to require the use of a port, most probably Whyalla, to receive reprocessed nuclear fuel waste by sea from France, the United Kingdom and the Lucas Heights reactor in NSW via Port Kembla.

Napandee. Site Characterisation Technical Report.
Department of Industry

The waste will be stored above ground in concrete vaults which will be filled for 100 years and monitored for a further 200-300 years.

Nuclear waste can remain hazardous for thousands of years.

The Barngarla people hold cultural rights and responsibilities for the region but were excluded from a government poll about the proposal because they were not deemed to be local residents.

The 734 locals who took part backed the proposal 61.6%

The Barngarla people are far from the first in South Australia to be excluded from a say about proposals to spread nuclear materials over their land.

It’s not the first such proposal

Australian Atomic Confessions explores the legacy of the nine British atomic bombs dropped on Maralinga and Emu Field in the 1950s, and the “minor trials” that continued into the 1960s.

After failed clean-ups by the British in the 1960s followed by a Royal Commission in the 1980s, the Australian Radiation Protection and Nuclear Safety Agency conducted a cleanup between 1995 and 2000 it assures us was successful to the point where most of the contaminated areas at Maralinga fall well within the clean-up standards applied for unrestricted land use.

But experts remain sceptical, given the near-surface burial of plutonium and contamination remaining across a wide area.

The Tjarutja people are allowed to move through and hunt at the Maralinga site with their radiation levels monitored but are not permitted to camp there permanently.

Nina Sanadze, 100 Years After, 30 years On, 3rd Tbilisi Triennial (2018) on display as part of The Image is not Nothing.
Sandro Sulaberidze

We are told that what happened in the 1950s wouldn’t happen today, in relation to the proposed nuclear waste dump. But it wasn’t our enemies who bombed us at Maralinga and Emu Field, it was an ally.

In exchange for allowing 12 British atomic bombs tests (including those at the Monte Bello Islands off the northern coast of Western Australia), the Australian government got access to nuclear technology which it used to build the Lucas Heights reactor.

It is primarily the nuclear waste produced from six decades of operations at Lucas Heights that would be dumped onto Barngarla country in South Australia, closing the links in this nuclear trauma chain.

Nuclear bombs and nuclear waste disproportionately impact Indigenous peoples, yet Australia still has not signed up to the United Nations Declaration on the Rights of Indigenous Peoples. The declaration requires states to ensure there is no storage or disposal of hazardous materials on the lands of Indigenous peoples without their free, prior and informed consent.

Article 29, United Nations Declaration on the Rights of Indigenous Peoples

Nor has Australia shown any willingness to sign up to the Treaty on the Prohibition of Nuclear Weapons which came into force on January 22 this year after a lobbying campaign that began in Australia and was endorsed by Indigenous leaders worldwide.

Aboriginal people have long known the dangers of uranium on their country.

Water from the Great Artesian Basin has been extracted by the Olympic Dam copper-uranium mine for decades. Fragile mound springs of spiritual significance to the Arabunna People are disappearing, posing questions for the mining giant BHP to answer.

Artworks on display at The Image is not Nothing at the Adelaide Festival.
Josh Geelen

Australian uranium from BHP Olympic Dam and the now-closed Rio Tinto Ranger mine fuelled the 2011 Fukushima nuclear disaster.

Senior traditional custodian of the Mirrar people, Yvonne Margarula, wrote to the United Nations in 2013 saying her people feel responsible for what happened.

It is likely that the radiation problems at Fukushima are, at least in part, fuelled by uranium derived from our traditional lands. This makes us feel very sad.

The Irati Wanti (The Poison, Leave It!) campaign led by a council of senior Aboriginal women helped defeat earlier proposals for nuclear waste dumps between 1998 and 2004.

There remains strong Indigenous opposition to the current nuclear waste proposal.

Over the past five years, farmers have joined with the Barngarla People to protect their communities and the health of the land.

In 2020 the government introduced into the Senate a bill that would do away with traditional owners’ and farmers’ rights to judicial reviews and procedural fairness in regard to the use of land for the facility.

Resources Minister Keith Pitt is deciding how to proceed.

Katherine Aigner, PhD candidate Centre for Aboriginal Economic Policy, Australian National University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Against the odds, South Australia is a renewable energy powerhouse. How on Earth did they do it?

Michael McGreevy, Flinders University and Fran Baum, Flinders University

Less than two decades ago, South Australia generated all its electricity from fossil fuels. Last year, renewables provided a whopping 60% of the state’s electricity supply. The remarkable progress came as national climate policy was gripped by paralysis – so how did it happen?

Our research set out to answer this question. We analysed policy documents and interviewed major actors in South Australia’s energy transition, to determine why it worked when so many others fail.

We found governments need enough political power to push through changes despite opposition from established fossil fuel interests. They must also watch the energy market closely to prevent and respond to major disruptions, such as a coal plant closing, and help displaced workers and their towns deal with the change.

South Australia shows how good public policy can enable dramatic emissions reduction, even in a privately owned electricity system. This provides important lessons for other governments in Australia and across the world.

Artist impression of SA solar plant — South Australia is a world leader in renewables deployment. Pictured: artist impression of solar thermal plant proposed for the state.
Solar Thermal Power Plant

Why is the energy transition so hard?

In decades past, fossil-fuel-dominated energy markets revolved around a few big, powerful players such as electricity generators and retailers. Overhauling such a system inevitably disrupts these incumbents and redistributes benefits, such as commercial returns, to newer entrants.

This can create powerful – and often vocal – losers, and lead to political problems for governments. The changes can also cause hardship for communities, which can be rallied to derail the transition.

The change is even harder in a privatised energy market, such as South Australia’s, where electricity generators and other players must stay profitable to survive. In the renewables shift, fossil fuel businesses can quickly become commercially unviable and close. This risks supply shortages, as well as price increases like those after Victoria’s Hazelwood coal plant closed in 2017.

The obstacles help explain why a wealthy nation such as Australia, with extremely high per capita emissions and cheap, plentiful renewable resources, has struggled to embrace its clean energy potential. Even frontrunners in environmental policy, such as Germany, have struggled to make the switch.

Coal workers and their communities must be assisted during the renewables transition.
Dan Himbrechts/AAP

How South Australia did it

South Australia is a dry state – extremely vulnerable to climate change – with abundant wind and solar resources. These factors gave it the motivation and means to transition to renewables.

The South Australian Labor government, elected in 2002, adopted a target for 26% renewables generation by 2020. At the time, wind energy was already a competitive supplier of new generation capacity in Europe, creating an established wind farm industry looking to invest.

Some of South Australia’s best onshore wind potential was located near transmission lines running 300 kilometres from Port Augusta to Adelaide. This greatly reduced the cost of connecting new wind generators to the grid.

South Australia benefited greatly from the federal renewable energy target, established by the Howard government in 2001 and expanded under the Rudd government.

The scheme meant the South Australian government didn’t need to offer its own incentives to meet its renewables target – it just had to be more attractive to private investors than other states. This was a relatively easy task. Under the state Labor government, South Australia’s energy and environment policy was consistent and coordinated, in contrast to the weak and inconsistent policies federally, and in other states.

To attract renewable energy investors, the government made laws to help construct wind farms in rural zones away from towns and homes. New wind farms were regularly underwritten by state government supply contracts.

As the transition progressed, the state’s largest coal generator, at Port Augusta, was wound back and eventually closed. To help workers and the town adjust, the state government supported employment alternatives, including a A$6 million grant towards a solar-powered greenhouse employing 220 people.

The Labor government enjoyed a long incumbency, and the state was not heavily reliant on the export of fossil fuels. This helped give it the political leverage to push through change in the face of opposition from vested interests.

Worker walks through greenhouse — A state government grant helped establish a solar greenhouse.
Sundrop Farms

It’s not easy being green

South Australia’s transition was not without controversy. Between 2014 and 2018, the state’s consumer electricity prices rose sharply. While critics sought to blame the increasing renewables share, it was largely due to other factors. These include South Australia’s continued reliance on expensive gas-fired power and the closure of the Hazelwood coal-fired power station in neighbouring Victoria, which fed large amounts of power into South Australia.

And in late 2016, South Australia suffered a statewide blackout. Again, renewables were blamed, when the disaster was in fact due to storm damage and overly sensitive trip switches.

After a second, smaller blackout six months later, the then federal treasurer Scott Morrison brought a lump of coal into parliament and argued South Australia’s renewables transition was:

…switching off jobs, switching off lights and switching off air conditioners and forcing Australian families to boil in the dark as a result of their Dark Ages policies.

In 2018, Labor lost office to a Liberal party highly critical of the renewables transition in opposition. But by then, the transition was well advanced. In our view, specific legislation would have been required to halt it.

The state Liberal government has now firmly embraced the renewables transition, setting a target for 100% renewable electricity by 2030. By 2050, the government says, renewables could generate 500% of the state’s energy needs, with the surplus exported nationally and internationally.

Scott Morrison, holding a lump of coal in Parliament, said SA’s renewables policy took the state back to the Dark Ages.
Lukas Coch/AAP

Leading the world

The South Australia experience shows a successful renewables transition requires that governments:

have enough political power to advance policies that disadvantage energy incumbents
monitor the energy market and respond proactively to disruptions
limit damage to displaced workers, businesses, consumers and communities.

It also highlights the importance of having transmission infrastructure near renewable resources before new generators are built.

As energy markets the world over grapple with making the clean energy transition, South Australia proves it can be done.

Michael McGreevy, Research Associate, Flinders University and Fran Baum, Matthew Flinders Distinguished Professor, Foundation Director, Southgate Institute for Health, Society & Equity, Flinders University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Enjoy them while you can? The ecotourism challenge facing Australia’s favourite islands

Remarkable Rocks, Kangaroo Island, South Australia.
Greg Brave/Shutterstock

Freya Higgins-Desbiolles, University of South Australia

I fell for Kangaroo Island from my first visit. I recall standing on a headland on the island’s southern coast, near Remarkable Rocks (a popular tourist site), and being awestruck by the Southern Ocean.

The island (Australia’s third-largest after Tasmania and Melville Island) is one of 16 designated National Landscapes and arguably South Australia’s greatest tourism treasure. Its protected areas (notably Flinders Chase National Park) are home to rare and endangered marsupials and birds.

A year ago, in Australia’s “Black Summer”, bushfires ravaged more than half the island (about 211,000 hectares). Those fires underscored the threat to this and other iconic island destinations.

Both directly and indirectly, humans are endangering these fragile ecosystems through unsustainable development and human-caused climate change.

The most ironic threat is from unsustainable tourism. These islands attract millions of visitors a year keen to experience their natural wonders. Yet often this very “ecotourism” is contributing to their degradation.

How to do better?

Last October I took part in a workshop at which Kangaroo Island’s tourism operators discussed how to do so. 2020 was a difficult year for them, first with the fires, then with the COVID-19 pandemic. But in that adversity they also saw the opportunity to reset “business as usual” and come back better, creating an industry not harming its core asset.

A range of ideas came out of our talks applicable to all our island destinations. But there was one key point. Ecotourism should be more than fleeting feel-good experiences. It should not be a “value extraction” but a “values education”, inspiring visitors to go home and live more eco-consciously.

Macquarie island

The paradox of ecotourism is perhaps best exemplified by Australia’s least visited island destination – Macquarie Island, about 1,500 km south-east of Hobart, halfway between New Zealand and the Antarctica.

Just 1,500 tourists a year, rather than hundreds of thousands, are permitted by the Tasmania Parks and Wildlife Service to visit. The island has no hotels, restaurants or souvenir shops. The only buildings are those of the Macquarie Island Station research base and a few isolated field huts for scientists.

The Macquarie Island Research Base.
Dale Lorna Jacobsen/Shutterstock

Tourists must be content with coming ashore for the day from the 18 small cruise ships that ply these waters in summer. The only hospitality is the traditional station offering of tea and scones.

But what tourists do get is a unique experience. Macquarie is World Heritage listed as the only island made entirely from the earth’s mantle. It also teems with wildlife – multiple species of penguins and seals in their tens of thousands, and birds in their millions.

Royal Penguins and Southern Elephant Seals at Sandy Bay, Macquarie Island.
Janelle Lugge/Shutterstock

It’s about as pure an ecotourism experience you can have (if you can afford it). Even so, it still takes resources to get there, including the burning of fossil fuels, contributing to the global warming that is the greatest threat to the environmental integrity of Macquarie Island (and other island ecosystems).

However, the Tasmania Parks and Wildlife Service does at least expect cruise ship operators to “demonstrate their capacity to deliver desirable outcomes” on criteria including minimisation of environmental impacts and communicating to tourists “messages about the natural and cultural values of the island”, including the role they play in its preservation.

K’gari (Fraser island)

Communicating such messages is something that certainly needs improvement on another World Heritage listed island – K’gari (commonly known as Fraser island), the world’s largest sand island.

About 250 km north of Brisbane, at the southern end of the Great Barrier Reef, the island draws many hundreds of thousands of visitors a year to its beaches, woodlands and rainforests. (There are no recent public statistics on island visitor numbers but in 2017-18 the Fraser Coast region attracted 1,515,000 visitors.)

Rainforest on K'gari. — Rainforest on K’gari.
Marco Saracco/Shutterstock

Once the island’s resources were mined and logged. Tourism was meant to be much less exploitative. But a range of organisations including the International Union for Conservation of Nature have highlighted the pressure tourist numbers (along with their vehicles and infrastructure) are placing on K’gari’s landscapes and wildlife.

Communicating to all those visitors the role they play in the island’s preservation appears to be failing. The bushfires that burnt half the island (about 165,500 hectares) over nine weeks between October and December last year allegedly resulted from an illegal camp fire.

Headline-grabbing attacks by the island’s residents dingos – such as in April 2019 when a toddler was dragged from a campervan – have also been credited to rampant irresponsible tourist behaviour (feeding dingoes to get better photos, for example).

Indigenous elders, conservationists and scientists have all pointed to the problem of a mass-tourism model that doesn’t put enough emphasis on educating visitors about the environment and their responsibilities.

Rottnest Island

One of our proposals for Kangaroo Island is to reduce the impact of motor vehicles through encouraging more extended walking and cycling experiences.

The value of sustainable transport as the foundation for ecotourism is demonstrated by Rottnest Island, 20 km off the coast of Perth.

The entire island is managed as an A-Class Nature Reserve. Apart from service vehicles and shuttle buses, it is car-free. You can hire a bike or bring your own to get around the island (11 km long and 4.5 km wide). Or simply walk.

The absence of traffic makes a Rottnest holiday a distinctly more relaxed experience. It’s a fair example of slow tourism; and, of course, it is also good for the island’s world famous quokkas, which co-exist with close to 800,000 visitors a year.

Rottnest island has the world’s only sizeable population of quokkas. There are 10,000 to 12,000 quokkas on the island.
Grakhantsev Nikolai/Shutterstock

Before they are gone

Given a little space, nature is resilient.

After Kangaroo Island’s bushfires a year ago, for example, it was feared a number of endangered species had finally been driven to extinction.

But in two of 2020’s few good news stories, scientists found critically endangered Kangaroo Island dunnarts and little pygmy possums – the world’s smallest marsupial – had survived.

Kangaroo Island pygmy possum.
Ashlee Benc/Kangaroo Island Land for Wildlife, CC BY

But we can’t take that resilience for granted if we keep putting pressure on these fragile ecosystems. We need a better approach to ensure ecotourism isn’t about enjoying these natural wonders before they are gone.

Freya Higgins-Desbiolles, Senior Lecturer in Tourism Management, University of South Australia

This article is republished from The Conversation under a Creative Commons license. Read the original article.

This super rare squid is a deep-sea mystery. We recently spotted not 1, but 5, in the Great Australian Bight

Hugh MacIntosh, Museums Victoria and Deborah Osterhage, CSIRO

The mysterious bigfin squid has been spotted in Australia’s waters for the first time. My colleagues and I from the CSIRO and Museums Victoria detail the encounters in our new research, published today in Public Library of Sciences ONE.

There have only been about a dozen bigfin squid sightings worldwide over the past two decades. Ours happened more than two kilometres below the ocean’s surface in the Great Australian Bight, off the coast of South Australia.

For many people, the phrase “deep-sea squid” may conjure up images of the giant squid, Architeuthis dux, or krakens with huge tentacles swimming in inky black water.

But there are dozens, if not hundreds, of other species of deep-sea squid and octopus (both members of the class Cephalopoda) that are just as mysterious.

First encounters with a slippery individual

For years, one of the only ways to sample the deep sea was to trawl the sea floor with nets. This often damaged the soft bodies of deep-sea organisms beyond recognition. These mangled specimens are then difficult to identify and reveal little to nothing about the creatures.

Fortunately, newer technologies such as remotely-operated vehicles (ROVs) equipped with high-definition cameras are letting scientists see species as they’ve never seen before — offering deeper insight into their shapes, colours and behaviours in the wild.

The enigmatic bigfin squid, Magnapinna, is one case in point. When scientists first described the species in 1998, all they had to go by were some damaged specimens from Hawaii.

The most distinctive feature of these specimens were the large fins (at the very top of the body), which gave the squid its name. Years later, scientists exploring the deep Gulf of Mexico with ROVs realised they had come across Magnapinna in the wild.

They discovered that in addition to its distinctive fins, its arms had incredibly long filaments on the tips, making the bigfin squid unlike any other encountered.

These delicate filaments, which are mostly broken off in collected specimens, give Magnapinna an estimated total length of up to seven meters!

In 2001, scientists exploring the seafloor off Oahu, Hawaii, captured footage of a bigfin squid estimated to be between four and six metres long.

Mysterious critters and where to find them

But despite deep-sea ROV surveys becoming more common, Magnapinna has remained elusive.

The handful of sightings have been as far apart as the Central Pacific, North and South Atlantic, Gulf of Mexico and Indian Ocean. This suggests a worldwide distribution.

Yet, the big fin squid had never been seen in Australian waters. That is, until recently, when our team took part in a major research project to better understand the biology and geology of the Great Australian Bight, through the Great Australian Bight Deepwater Marine Program.

On the CSIRO’s research vessel Investigator and charter vessel REM Etive, we surveyed as deep as five kilometres below the water’s surface. Using nets, ROVs and other camera equipment, we recorded hundreds of hours of video footage and uncovered thousands of species.

On one dive, as we watched the video feed from cameras far below us, a wispy shape emerged from the gloom. With large undulating fins, a small torpedo-shaped body and long stringy limbs, it was unmistakably Magnapinna. We yelled and brought the ROV to a halt to get a better look.

The meeting lasted about three minutes. During this time we managed to use parallel laser pointers to measure the squid’s length — about 1.8 meters — before it swam away into darkness.

In total, we recorded five encounters with Magnapinna in the Great Australian Bight. Based on the animals’ measurements, we believe we recorded five different individuals: the most Magnapinna ever filmed in one place.

Most previous records have been of single Magnapinna, but our five squid were all found clustered close to each other. This might mean they like the habitat where they were found, but we’ll need more sightings to be sure.

Unexplained behaviours

The footage we captured has offered new information about Magnapinna’s ecology, behaviour and anatomy.

Previously, Magnapinna has been seen many meters off the sea floor in an upright posture, with arms held wide and filaments draping down. We’re not sure what the specific function of this behaviour is. It might be a way to find prey — akin to dangling sticky, sucker-covered fishing lines.

On our voyage, we saw the squid in a horizontal version of this pose, just centimetres off the sea floor, with its arms and filaments streaming behind. Again, we don’t know whether this behaviour is for travelling, avoiding predators or another method of searching for prey.

If you look at this photo carefully, you can a bigfin squid with its arms spread wide, and its filaments as faint lines stretching away to the bottom right.
Osterhage et al.

One near-miss with a camera gave us a very closeup image of Magnapinna which showed filaments that appeared to be coiled like springs. This may be a means for Magnapinna to retract its filaments when needed, perhaps if it wanted to avoid damage, or reel in something it caught.

Until now, only one other cephalopod, the vampire squid (Vampyroteuthis infernalis), has been known to coil its filamentous appendages this way.

A close encounter just centimetres off the seabed shows the squid in a horizontal posture, with its arms spread and filaments dragging behind. Curiously, some of the filaments appear to be coiled like springs.
Osterhage et al.

We have learned more about the mysterious bigfin squid. But until we have more sightings, or even an intact specimen, questions will remain.

One thing we do know is ROV surveying has great potential to enhance our understanding of deep-sea animals. With so much of the ocean around Australia yet to be explored, who knows what we’ll see coming out of the gloom next time?

Hugh MacIntosh, Research Associate, Marine Invertebrates, Museums Victoria and Deborah Osterhage, Marine Scientist, Oceans and Atmosphere, CSIRO

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Fire-ravaged Kangaroo Island is teeming with feral cats. It’s bad news for this little marsupial

Rosemary Hohnen, Charles Darwin University and Sarah Legge, Australian National University

When I visited Kangaroo Island for the first time after the summer bushfires, I thought I knew what to expect. But what really hit me was the scale.

The wild western end of the island, once a vast mallee woodland peppered with wildflowers and mobs of roaming roos, had been completely erased. An immense dune field covered with sharp blackened sticks now stretched beyond the horizon, to the sea, hollow and quiet.

While fire is a fundamental process in many Australian ecosystems, the size and severity of this fire was extreme, and the impacts on the island’s wildlife has been immense.

For the many threatened species on Kangaroo Island, such as the critically endangered Kangaroo Island dunnart, their fight for survival still isn’t over. High numbers of feral cats roaming the landscape now pose a huge threat to their persistence, with little vegetation left within the fire scar to provide cover for wildlife.

In fact, our recent research found there are, on average, almost double the number of cats per square kilometre on Kangaroo Island than on the mainland.

The scale of the fires

Kangaroo Island is uniquely positioned, home to wildlife native to both eastern and western Australia. It protects nationally threatened species, such as the glossy black-cockatoo, the pygmy copperhead, Rosenberg’s goanna and the Kangaroo Island dunnart.

The recent bushfires on Kangaroo Island were the largest ever recorded there, destroying swathes of habitat. Over a period of 49 days the fire burnt 211,255 hectares, impacting almost half of the island, particularly the western and central regions.

For the critically endangered Kangaroo Island dunnart, the fires burnt approximately 95% of the species’ known habitat and left them on the brink of extinction.

Dunnarts face extinction

The Kangaroo Island dunnart is a small carnivorous marsupial weighing about 20 grams, with soft sooty fur and dark eyes. The species eats mainly insects, and shelters in hollow logs and in the skirts of grass trees.

Even prior to the fire the species was considered likely to become extinct in the next 20 years. Despite extensive survey efforts, the dunnart had only been seen at 19 sites on Kangaroo Island between 1990 and 2019.

Our own survey work between 2017 and 2018 confirmed the persistence of the dunnart at just six sites in the national park, with Kangaroo Island Land for Wildlife detecting several additional records on private land. All sites were in the western half of the island where the recent fires burned.

Many dunnarts are likely to have died in the fire itself, but individuals that survived are left extremely vulnerable to starvation and feral cat predation.

Cats roaming the island in big numbers

Between two and six million feral cats are estimated to live in Australia, and collectively kill more than three billion animals per year.

The problem is so large, a parliamentary inquiry is, for the first time in 30 years, investigating the impact of feral and domestic cats to native wildlife.

What’s more, in some areas on Kangaroo Island where the availability of animal carcasses is high, the density of feral cats is more than ten times as high as mainland estimates.

There are twice as many cats per square kilometre on Kangaroo Island than on mainland Australia.
Shutterstock

A high cat density poses a formidable threat to wildlife survival during the post-fire period, because cats will sometimes travel large distances to hunt within recent fire scars. Research is underway on the island to examine exactly how the fires have changed cat densities and hunting behaviour in and around burnt areas.

How to control feral cats

Controlling feral cats is one of the biggest challenges in Australian conservation. Cats are cryptic and cautious, hard to find, see, trap and remove.

Despite the challenge, a large-scale feral cat eradication is underway on Kangaroo Island. This is the largest island on which cat eradication has ever been attempted, and the project will take years.

In the meantime, feral cats are being controlled around the last refuges for Kangaroo Island dunnarts. There are multiple methods for this including shooting and cage trapping, but in remote areas that are hard to access, poison-baiting is likely to be an effective, long-term strategy.

Most feral cat baits are meat-based, but our research shows possums and bush rats are still likely to consume them.

Therefore, researchers have worked for many years on strategies to minimise the potential impacts of feral cat baits on native wildlife. For example, the poison can be delivered within a hard plastic pellet, inside the meat bait.

Field trials have indicated that while cats swallow portions of this bait whole, ingesting the pellet, most native wildlife will chew around and discard the pellet.

Hope emerges after huge survey effort

Despite the gravity of the risk to Kangaroo Island wildlife, there is hope. A huge, dedicated and effective survey effort by both government and non-government organisations has resulted in the detection of Kangaroo Island dunnarts at more than 22 sites.

Kangaroo Island dunnarts have been spotted in devastated parts of the landscape.
Jody Gates, Author provided

These small populations have been found mostly within patches of unburnt vegetation, but also – almost unbelievably – in areas that have been completely burnt.

Many of these populations appear to be very small and isolated. And now, more than ever, they’re extremely vulnerable. Targeted cat control and/or protection of vulnerable populations with exclusion fencing may be the only way to prevent their extinction.

By controlling cats, we can help native species like the Kangaroo Island dunnart get through this difficult time, and continue to fulfil their place in that wild landscape for years to come.

The authors would like to acknowledge and thank Paul Jennings, Pat Hodgens, Heidi Groffen, James Smith and Trish Mooney, for their generous contributions to this article.

Rosemary Hohnen, Adjunct associate, Charles Darwin University and Sarah Legge, Professor, Australian National University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

I’m searching firegrounds for surviving Kangaroo Island Micro-trapdoor spiders. 6 months on, I’m yet to find any

Jess Marsh, Murdoch University

This article is part of Flora, Fauna, Fire, a special project by The Conversation that tracks the recovery of Australia’s native plants and animals after last summer’s bushfire tragedy. Explore the project here and read more articles here.

I’m standing on a hill in Kangaroo Island’s Western River Wilderness Protection Area, looking over steep gullies and sweeping hillsides. As far as I can see, the landscape is burnt: bright patches of regrowth contrast with skeletal, blackened trunks. It’s stark, yet strangely beautiful.

It’s late May, five months after the catastrophic summer fires burned 90% of the park. I’m here to assess the damage to some of our tiniest Australians.

Much attention has been given to the plight of Kangaroo Island’s iconic birds and mammals – the Glossy Black Cockatoo and the Kangaroo Island Dunnart, for example. However, the invertebrates – spiders, insects and myriad other groups – have largely been overlooked. These groups contain some of Australia’s most threatened species.

Among the invertebrates listed by the federal government as a priority for intervention is an unassuming, brownish-black spider with squat legs and a body about the size of a A$2 coin. Its name: the Kangaroo Island Micro-trapdoor spider (Moggridgea rainbowi).

The trials it now faces offer an insight into the enormous challenges ahead for invertebrates – the tiny engines of Australia’s biodiversity – in the wake of last summer’s cataclysmic fires.

A female Kangaroo Island Micro-trapdoor spider (*Moggridgea rainbowi*)
Jess Marsh, Author provided

The sea-faring spider

The Kangaroo Island Micro-trapdoor spider has an interesting history. It is the only member of its genus found in Australia, its closest relative being in Africa. Studies show it arrived here between 2 and 16 million years ago, likely rafting across the ocean on vegetation! A true voyager.

Kangaroo Island Micro-trapdoor spiders exist only on Kangaroo Island. They live in short, 6cm burrows, built neatly into creek banks. They are slow, calm spiders, spending most of their time in their burrow, determinedly holding the door shut with their fangs.

The females care for their young; I have opened a trapdoor to find 20 tiny spiders living together with their mother. When ready, the young disperse short distances to build burrows of their own, tiny versions of the adult’s.

When ready, young Kangaroo Island Micro-trapdoor spiders build their own burrows not far from their mothers’.
Jess Marsh, Author provided

Assessing the damage

My colleagues and I are in this conservation park today to locate patches of less fiercely burnt land in which to look for survivors. Sadly, all the known western populations of this enigmatic spider were destroyed. I am yet to find any survivors in the fire ground, but it is early days.

We will be out here for the next year or so, walking hundreds of kilometres of creek lines, searching for signs of life. There is a lot of land out there. Around 210,000 hectares was burnt, almost half of Kangaroo Island. I remain hopeful that some colonies have survived.

If we find some Kangaroo Island Micro-trapdoor spiders – what then?

Surviving the initial blaze is the first step in the struggle for survival. The post-fire environment has many threats – habitat loss, exposure to hungry predators, weeds. Today, I noticed areas where soil, loosened by fire, has washed into creeks, completely burying them.

If we find some surviving individuals, we’ll protect them by installing sediment control, removing weeds and monitoring them in future.

Why should we care?

Not everyone loves spiders. I get that. But the functions invertebrates perform are vital. Our ecosystem relies on them; humans rely on them. Yet collectively our understanding of invertebrates – their importance and their value – is dangerously low.

The Kangaroo Island Micro-trapdoor Spider plays its own role the ecosystem. It is a predator, but we don’t really know what it eats. It’s a food source for birds, mammals or reptiles, but we don’t know what eats it. So, why should we care?

Firstly, I firmly believe every species has its own intrinsic value; every extinction, although a natural part of life, is a loss.

Secondly, the ecosystem is so complicated we don’t know exactly how the loss of one species will impact its prey, the parasites that live on it or its predators. And when we’re facing multiple extinctions, these effects could be devastating.

The Kelly Hill Conservation Park in Kangaroo Island was badly burnt in last summer’s fires.
Jess Marsh, Author provided

The Kangaroo Island Micro-trapdoor spider, the Kangaroo Island Assassin Spider, the Green Carpenter Bee – we only know these species are threatened because scientists like me have spent years or decades studying them.

But the majority of Australia’s invertebrate species are yet to be discovered. Many will be similarly at risk, but we have no way of measuring the scale of risk or the repercussions. That’s a fact we should all find scary.

There is hope, though. It’s not yet over for these species. Work such as ours is a step towards understanding how worsening bushfires will affect these vital, but often forgotten, members of our ecosystem.

Jess Marsh, Research fellow at the Harry Butler Institute, Murdoch University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

‘Jewel of nature’: scientists fight to save a glittering green bee after the summer fires

Katja Hogendoorn, University of Adelaide; Remko Leijs, Flinders University, and Richard V Glatz, University of Adelaide

This article is a preview of Flora, Fauna, Fire, a multimedia project launching on Monday July 13. The project tracks the recovery of Australia’s native plants and animals after last summer’s bushfire tragedy. Sign up to The Conversation’s newsletter for updates.

The green carpenter bee (Xylocopa aerata) is an iconic, beautiful native species described as a “jewel of nature” for its metallic green and gold colouring. Carpenter bees are so named because they excavate their own nests in wood, as opposed to using existing holes.

With a body length of about 2 centimetres, it is among the largest native bees in southern Australia. While not used in honey farming, it is an important pollinator for several species of Australian native plants.

Last summer’s catastrophic bushfires significantly increased the risk of local extinctions of this magnificent species. We have studied the green carpenter bee for decades. For example, after the 2007 fires on Kangaroo Island, we bolstered the remaining population by providing nesting materials.

To see our efforts – and more importantly, most of the habitat these bees rely on – destroyed by the 2020 fire was utterly devastating.

Much of Kangaroo Island was incinerated by the summer bushfires.
Daniel Mariuz/AAP

A crucial pollinator on the brink

The green carpenter bee is a buzz-pollinating species. Buzz pollinators are specialist bees that vibrate the pollen out of the flowers of buzz-pollinated plants.

Many native plants, such as guinea flowers, velvet bushes, Senna, fringe, chocolate and flax lilies, rely completely on buzz-pollinating bees for seed production. Introduced honey bees do not pollinate these plants.

The green carpenter bee went extinct on mainland South Australia in 1906 and in Victoria in 1938. It still occurs on the relatively uncleared western half of Kangaroo Island in South Australia, in conservation areas around Sydney, and in the Great Dividing Range in New South Wales.

Local extinctions were probably due to habitat clearing and large, intense bushfires. The last time the green carpenter bee was seen in Victoria was early December 1938 in the Grampians, which burnt completely during the Black Friday fires of January 1939.

There are several reasons green carpenter bees are vulnerable to fire, including:

the species uses dead wood for nesting, which burns easily
if the nest burns before the offspring matures in late summer, the adult female might fly away but won’t live long enough to reproduce again, and
the bees need floral resources throughout the year.

A male green carpenter bee.
Remko Leijs, Author provided

Nowhere to nest

The bees mainly dig their nests in two types of soft wood: dry flowering stalks of grass trees and, crucially important, large dead Banksia trunks. The availability of both nesting materials is intricately connected with fire.

Green carpenter bees sometimes nest n the dried flowering stalks of grass trees, also known as *Xanthorrhoea*.
Remko Leijs, Author provided

Grass trees flower prolifically after fire, but the dry stalks are only abundant between two and five years after fire. Banksia species don’t survive fire, and need to grow for at least 30 years to become large enough for the bees to use.

Bees nesting in an artificial stalk.
Remko Leijs, Author provided

With increasingly frequent and intense fires, there’s not enough time for Banksia trunks to grow big enough, before they’re wiped out by the next fire.

A helping hand after the 2007 fires

In 2007, Flinders Chase National Park on Kangaroo Island burnt almost entirely.

An artificial stalk nesting site installed in a *Xanthorrea*.
Remko Leijs, Author provided

However, in long-unburnt areas adjacent to the park, carpenter bee nests were still present. From there, they colonised the many dry grass tree stalks that resulted from the fire in the park.

In 2012, most flowering stalks had decayed. In an attempt to bolster population size, we successfully developed artificial nesting stalks to tide the bees over until new Banksia, suitable for nesting, would become available.

Since then, each year we’ve placed artificial nesting stalks in fire-affected areas where the bee still occurred. Almost 300 female carpenter bees have successfully used our stalks to raise their offspring.

Then came the January 2020 fires

At the time of the 2020 fires on Kangaroo Island, there were more than 150 nests containing mature brood in the stalks we had provided.

We’d placed these in 12 sites in and around Flinders Chase National Park, to spread risk – to no avail, as they all burnt.

We were horrified to see the intensity and speed of the fire that turned our efforts to ash, along with most of the remnant, long (more than 60 years) unburnt Banksia habitat the bees rely on. In New South Wales, much of the species’ natural range was also burnt.

The yellow dots represent known green carpenter bee nests. In red: the area burnt in 2020. Only a subset of the remaining green and yellow patches still have the right vegetation for the green carpenter bee.
Nature Maps SA/Remko Leijs, Author provided

What’s next for the green carpenter bee?

To fully appreciate the impact, we need to survey the remaining long unburnt areas on Kangaroo Island and in NSW.

Encouragingly, we have already found a few natural nests on Kangaroo Island, but the remaining suitable areas are small and isolated, and densities are likely to be low.

With funds raised through the Australian Entomological Society and the Wheen Bee Foundation, and with help of the Kingscote Men’s Shed, we are making new nesting stalks.

The Kingscote Men’s Shed on Kangaroo Island is helping build new nesting stalks.
Remko Leijs, Author provided

With permission of landholders, we’ll place these new stalks in areas with good floral support, to enhance reproduction and help the bees disperse into conservation areas once suitable.

As we have learnt, success is not guaranteed. Extensive and repeated bush fires, combined with asset protection and fuel reduction burns, are making longtime unburnt habitat increasingly rare. It is this lack of old, continuous, unburnt forest that severely threatens the green carpenter bees’ existence.

The future of fire-vulnerable biodiversity

The carpenter bee is not the only species facing this problem. Many Australian plants and animals are not resilient to high frequency fires, no matter their intensity or time of year.

The ecological importance of longtime unburnt forest needs urgent recognition, as increased fire frequency – both of natural and “managed” fires – is likely to drive a suite of species to extinction.

For Kangaroo Island, this could include several small mammals, glossy black cockatoos, and a range of invertebrate species, including the green carpenter bees.

Given the expected increase in fire frequency and intensity associated with global heating, it’s time we recognise fire-vulnerable species as a category that requires urgent habitat protection.

Katja Hogendoorn, University of Adelaide; Remko Leijs, Researcher, Flinders University, and Richard V Glatz, Associate research scientist, University of Adelaide

This article is republished from The Conversation under a Creative Commons license. Read the original article.

It’s official: expert review rejects NSW plan to let seawater flow into the Murray River

Jamie Pittock, Australian National University; Bruce Thom, University of Sydney; Celine Steinfeld; Eytan Rocheta, UNSW, and Nicholas Harvey, University of Adelaide

A major independent review has confirmed freshwater flows are vital to maintaining the health of the Murray River’s lower lakes, striking a blow to demands by New South Wales that seawater flow in.

The review, released today, was led by the CSIRO and commissioned by the Murray Darling Basin Authority. It examined hundreds of scientific studies into the lower lakes region of South Australia, through which the Murray River flows before reaching the ocean.

The review recommends managing the lakes with freshwater, not seawater. More importantly, it highlights how climate change and upstream farming is reducing the flow of water for the environment in the lower lakes.

These findings are critically important. They show the severe health threat still facing the river system and its internationally important wetlands. They also cast doubt on whether the A$13 billion basin plan can achieve all its aims.

A plan to save the parched Murray Darling system may not succeed.
Dean Lewins/AAP

A barrage of criticism

The Murray Darling river system runs from Queensland, through NSW, the ACT and Victoria. In South Australia the River Murray discharges into two large lakes, Alexandrina and Albert, before flowing into the 130 kilometre-long Coorong lagoon, through the Murray Mouth and into the ocean.

Since 1940 five low dams, or barrages, have stopped seawater flowing into the lakes from the Murray Mouth and Coorong, and raised the lakes’ water level.

NSW wants the barrages lifted to allow seawater back into Lake Alexandrina, to free up freshwater for agriculture upstream.

In December 2019, NSW Nationals John Barilaro said: “I refuse to let regional communities die while we wash productive water into the Great Australian Bite (sic), 1000km away”. Irrigation advocates have backed his calls.

Victoria has also questioned whether the lower lakes can continue to be kept fresh, given the water scarcity plaguing the entire river system.

But today’s review confirmed the lower lakes were largely a freshwater ecosystem prior to European occupation. It said removing the barrages would cause significant ecological and socioeconomic harm, and would not lead to water savings if the basin plan targets are to be met.

The Murray Mouth is choking

The review cited research we published this month, which concluded it was impossible to achieve the basin plan target to keep the Murray Mouth open 95% of the time.

This is because Murray Darling Basin Authority modelling did not factor in the power of the Southern Ocean to move sand into the Murray Mouth, which is now choked. Dredging will be required most of the time to keep the Murray Mouth open and maintain the ecology of the Coorong.

The Coorong and Lakes Alexandrina and Albert are a wetland of international importance under the Ramsar Convention.

The review found removing the barrages would significantly change the freshwater character of the site, which we have an international obligation to maintain for the sake of waterbirds, fisheries and threatened species.

This is becoming harder during periods when freshwater inflows are scarce. In the Millennium Drought for example, lake levels fell exposing highly acidic mudflats. In other areas, the waters became more salty.

After the basin plan was adopted in 2012, the condition of the lower lakes improved when the Millennium Drought broke and environmental flows were delivered, sustaining the system in the current drought. But very little of those flows enter the sea, except during floods.

The system of barrages in the lower lakes consist of 593 gates. Using official data, we calculate that for 70% of the time since 2007, fewer than ten gates have been open to the sea. For one-third of the time, none were open, indicating there is insufficient water to sustain fisheries and flush salt to the ocean.

Our research concludes that without the barrages the sand banks will reduce the volume of water flowing through the Murray Mouth. The tides would not be strong enough to keep the lakes flushed so water quality would decline. No barrages means lower lake levels and exposed mudflats, generating sulphuric acid.

Aerial view of the Murray River barrages, circa 1940.
State Library of South Australia

An uncertain future

The review reinforces the South Australian government’s position that the lakes should be maintained with freshwater. It also obliges the federal government to implement the basin plan in its current form, despite NSW’s demands for changes.

The final report also highlighted how climate change will make management of the Coorong, Lower Lakes and Murray Mouth “increasingly challenging” and said adaptation options were needed for the entire river system.

By the end of this century, rising seas may flow over the barrages. Maintaining freshwater inflows and the barrages buys us time, but we need a serious national conversation about how to manage this challenge.

The federal and South Australian governments recently announced a Coorong Partnership to enable local communities and groups participate in programs to improve management of the lagoon. This is timely and should be expanded to cover the broader Lower Lakes and Murray Mouth regions.

Freshwater flowing from the headwaters to the sea is vital for the health of the Murray-Darling Basin as a whole. Today’s report should be the start of the national discussion on shoring up the health of Australia’s most important river system in the face of an uncertain future.

Jamie Pittock, Professor, Fenner School of Environment & Society, Australian National University; Bruce Thom, Emeritus Professor, University of Sydney; Celine Steinfeld, Acting Director, Wentworth Group of Concerned Scientists & Adjunct Lecturer at UNSW Sydney; Eytan Rocheta, Policy Analyst, Wentworth Group of Concerned Scientists & Adjunct Associate Lecturer at UNSW Sydney, UNSW, and Nicholas Harvey, , University of Adelaide

This article is republished from The Conversation under a Creative Commons license. Read the original article.

A British nuclear playground

Hot potatoes

Nanotechnology to the rescue

From fire to dust

Share this:

Like this:

A gas-led economic recovery

Bad: investing in gas

Good: investing in critical infrastructure

The verdict

Share this:

Like this:

It’s not the first such proposal

Share this:

Like this:

Why is the energy transition so hard?

How South Australia did it

It’s not easy being green

Leading the world

Share this:

Like this:

Macquarie island

K’gari (Fraser island)

Rottnest Island

Before they are gone

Share this:

Like this:

First encounters with a slippery individual

Mysterious critters and where to find them

Unexplained behaviours

Share this:

Like this:

The scale of the fires

Dunnarts face extinction

Cats roaming the island in big numbers

How to control feral cats

Hope emerges after huge survey effort

Share this:

Like this:

The sea-faring spider

Assessing the damage

If we find some Kangaroo Island Micro-trapdoor spiders – what then?

Why should we care?

Share this:

Like this:

A crucial pollinator on the brink

Nowhere to nest

A helping hand after the 2007 fires

Then came the January 2020 fires

What’s next for the green carpenter bee?

The future of fire-vulnerable biodiversity

Share this:

Like this:

A barrage of criticism

The Murray Mouth is choking

An uncertain future

Share this:

Like this: