What’s the economic value of the Great Barrier Reef? It’s priceless

Neil Perry, Western Sydney University

Deloitte Access Economics has valued the Great Barrier Reef at A$56 billion, with an economic contribution of A$6.4 billion per year. Yet this figure grossly underestimates the value of the reef, as it mainly focuses on tourism and the reef’s role as an Australian icon.

When you include aspects of the reef that the report excludes, such as the ecosystem services provided by coral reefs, you find that the reef is priceless.

Putting a price on the Great Barrier Reef buys into the notion that a cost-benefit analysis is the right way to make decisions on policies and projects that may affect the reef. For example, the environmental cost of the extension to the Abbot Point coal terminal can be compared to any economic benefits.

But as the reef is both priceless and irreplaceable, this is the wrong approach. Instead, the precautionary principle should be used to make decisions regarding the reef. Policies and projects that may damage the reef cannot go ahead.

How do you value the Great Barrier Reef?

The Deloitte report uses what’s known as a “contingent valuation” approach. This is a survey-based methodology, and is commonly used to measure the value of non-market environmental assets such as endangered species and national parks – as well as to calculate the impact of events such as oil spills.

In valuing the reef, surveys were used to elicit people’s willingness to pay for it, such as through a tax or levy. This was found to be A$67.60 per person per year. The report also uses the travel-cost method, which estimates willingness to pay for the Great Barrier Reef, based on the time and money that people spend to visit it. Again, this is commonly used in environmental economics to value national parks and the recreational value of local lakes.

Of course, all methods of valuing environmental assets have limitations. For example, it is difficult to make sure that respondents are stating realistic amounts in their willingness to pay. Respondents may act strategically if they think they really will be slugged with a Great Barrier Reef levy. They may conflate this environmental issue with all environmental issues.

But more importantly, the methodology in the report leaves out the most important non-market value that the reef provides, which are called ecosystem services. For example, coral reefs provide storm protection and erosion protection, and they are the nurseries for 25% of all marine animals which themselves have commercial and existence value.

The Deloitte report even cites (but does not reference) a 2014 study that values the ecosystem services provided by coral reefs at US$352,249 per hectare per year. The Great Barrier Reef Marine Park covers 35 million hectares with 2,900 individual reefs of varying sizes. This means the ecosystem services it provides are worth trillions of dollars per year.

That is, it is essentially priceless.

The problem with putting a value on the Reef

Valuing the environment at all is contentious in economics. Valuation is performed so that all impacts from, say, a new development, can be expressed in a common metric – in this case dollars. This allows a cost-benefit analysis to be performed.

But putting a price on the Great Barrier Reef hides the fact that it is irreplaceable, and as such its value is not commensurate with the values of other assets. For instance, using Deloitte’s figure, The Australian newspaper compared the reef to the value of 12 Sydney Opera Houses. But while they are both icons, the Opera House can be rebuilt. The Great Barrier Reef cannot. Any loss is irreversible.

When environmental assets are irreplaceable and their loss irreversible, a more appropriate decision-making framework is the Precautionary Principle.

The Precautionary Principle suggests that when there is uncertainty regarding the impacts of a new development on an environmental asset, decision makers should be cautious and minimise the maximum loss. For example, if it is even remotely possible that the extension to the Abbot Point coal terminal could lead to massive destruction of the reef, then precaution suggests that it shouldn’t go ahead.

Assigning a value to the reef might still be appropriate under the Precautionary Principle, to estimate the maximum loss. But it would require the pricing of all values and especially ecosystem services.

While the Precautionary Principle has been much maligned due to its perceived bias against development, it is a key element of the definition of Ecologically Sustainable Development in Australia’s Environment Protection and Biodiversity Conservation Act 1999.

For a priceless asset like the Great Barrier Reef, it is perhaps better to leave it as “priceless” and to act accordingly. After all, if the Precautionary Principle is ever going to be used when assessing Ecologically Sustainable Development, in contrast with cost-benefit analysis and valuations, it is surely for our main environmental icon.

Ultimately, the protection and prioritisation of the Great Barrier Reef is a political issue that requires political will, and not one that can be solved by pricing and economics.

Neil Perry, Research Lecturer, Western Sydney University

This article was originally published on The Conversation. Read the original article.

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What do we tell kids about the climate change future we created for them?

Marc Hudson, University of Manchester

Over the past two years The Conversation has published my analyses on a range of topics related to climate change and politics, including climate denial in the Liberal Party, 25-year-old cabinet papers (not once but twice), coal industry PR campaigns and much else besides.
Finally comes a topic I can cheerfully say I know nothing about (at first hand, at least): raising children.

Apologies for oversharing, but I had a vasectomy in 2004. The columnist Andrew Bolt spotted this, via an article in Britain’s Daily Mail which clearly stated that I was the one who had been under the knife. Bolt claimed that my wife had “sterilised herself”. (She does a lot of yoga, but she’s not that flexible. We have pointed this out but Bolt has kept at it, repeating the claim almost six years later).

Despite what the Daily Mail article says (and what is within the quotes was never said), our decision not to have kids wasn’t based on concern for what our hypothetical children would do to the planet, but rather what the planet would do to them. My wife copped some online abuse, and I was once disinvited to appear on the BBC after explaining my actual position.

I first switched on to climate change in about 1989, and have become convinced that the second half of the 21st century will probably make the first half of the 20th look like a golden age of peace and love. There have been 30 years of promises and pledges, protocols and agreements, while atmospheric greenhouse gas levels have climbed remorselessly due to humanity’s emissions. I suspect that the reported recent flatlining in emissions growth could well turn out to be as illusory as the so-called global warming “hiatus”.

Writing recently in the Sydney Morning Herald, climate scientist Sophie Lewis eloquently asked:

Should we have children? And if we do, how do we raise them in a world of change and inequity? Can I reconcile my care and concern for the future with such an active and deliberate pursuit of a child? Put simply, I can’t.

While I would never presume to tell anyone what to do with their genitals, I must confess my personal amazement that climate activists who do have children – and who I know have read the same scientific research as me and drawn the same conclusions – aren’t freaking out more. (Perhaps they are just very tired.)

As the Manic Street Preachers sagely warned, our children will have to tolerate whatever we do, and more besides.

Be prepared?

So how do we prepare tomorrow’s adults for the world bequeathed to them by the adults of yesterday and today? Even the mainstream media is beginning to ask this question.

Some studies say young people don’t care enough about climate change; others claim they do. The Australian picture seems to be mixed.

As the environmental writer Michael McCarthy has lamented:

A new edition of the Oxford Junior Dictionary was published in 2007 with a substantial group of words relating to nature – more than 50 – excised: they included acorn, adder, ash, beech, bluebell, buttercup, catkin, conker, cowslip and dandelion. Their replacements included terms from the digital world such as analogue, blog, broadband, bullet-point, celebrity, chatroom, cut-and-paste, MP3 player and voicemail.

Might we be more adaptive than we think? The social demographers Wolfgang Lutz and Raya Muttarak, in their snappily titled paper Forecasting societies’ adaptive capacities through a demographic metabolism model, think so, describing how “the changing educational composition of future populations” might help societies adapt to climate change.

But not everyone thinks our brains will get us out of the mess that they and our opposable thumbs have got us into. As an editor at the Daily Climate pointed out:

A substantial portion of the human population lives on coasts. Much of their protein comes from fish. What happens when ocean acidification turns all of that to slime?

So what should we tell kids about climate?

It always helps to be open to advice from different settings. For instance, I stumbled on this good advice on a blog aimed at military spouses, but it strikes me that it holds just as true for the climate-concerned:

It is okay to show sadness around your kids; in fact, it is probably healthy. However, it is not okay to dump your emotions on them. Save rants and deep conversations for trusted adults.

If you are feeling overwhelmed (and you will), don’t turn to your kids. Children are usually helpless to offer advice and it can cause them to experience anxiety. Seek help from an adult friend … extended family, a neighbor, your church, or a counselor.

Sophie Lewis sensibly hopes that the next generation(s) “can be more empathetic, more creative and more responsive than we have been”. It’s a noble hope, but it will only happen if we behave differently.

So as previously in this column, it’s over to you, the readers. I have a couple of questions for you:

First, how do those of you who are parents (and grandparents, aunts and uncles) talk to your children about the climate change impacts that will happen in their lifetimes? Avoidance? Sugar-coating? The “straight dope”? Do you slip books from the burgeoning fields of dystopian fiction and “cli-fi” into their Christmas stockings? Besides The Hunger Games, there is Tomorrow, When the War Began, the excellent Carbon Diaries and, more recently, James Bradley’s The Silent Invasion. Do you worry about scaring the kids? What do the youngsters themselves say?

Second, what steps are you taking to help young people develop the (practical and interpersonal) skills required to survive as times get tougher? What are those skills? How do we make sure that it isn’t just the few (children of the rich and/or the “switched on”) who gain these skills?

Marc Hudson, PhD Candidate, Sustainable Consumption Institute, University of Manchester

This article was originally published on The Conversation. Read the original article.

Globally, floods seem to be decreasing even as extreme rainfall rises. Why?

Seth Westra, University of Adelaide and Hong Xuan Do, University of Adelaide

Over the past decade we have seen a substantial increase in our scientific understanding of how climate change affects extreme rainfall events. Not only do our climate models suggest that heavy rainfall events will intensify as the atmosphere warms, but we have also seen these projections start to become reality, with observed increases in rainfall intensity in two-thirds of the places covered by our global database.

Given this, we might expect that the risk of floods should be increasing globally as well. When it comes to global flood damage, the economic losses increased from roughly US$7 billion per year in the 1980s to US$24 billion per year in 2001-11 (adjusted for inflation).

It would be natural to conclude that at least some of this should be attributable to climate change. However, we know that our global population is increasing rapidly and that more people now live in flood-prone areas, particularly in developing countries. Our assets are also becoming more valuable – one only needs to look at rising Australian house prices to see that the values of homes at risk of flooding would be much greater now than they used to be in decades past.

So how much of this change in flood risk is really attributable to the observed changes in extreme rainfall? This is where the story gets much more complicated, with our new research showing that this question is still a long way from being answered.

Are floods on the rise?

To understand whether flood risk is changing – even after accounting for changes in population or asset value – we looked at measurements of the highest water flows at a given location for each year of record.

This sort of data is easy to collect, and as such we have reasonably reliable records to study. There are more than 9,000 streamflow gauges around the world, some of which have been collecting data for more than a century. We can thus determine when and how often each location has experienced particularly high volumes of water flow (called “large streamflow events”), and work out whether its flood frequency has changed.

A streamflow gauging station in Scotland.
Jim Barton/Wikimedia Commons, CC BY-SA

We found that many more locations have experienced a decrease in large streamflow events than have experienced an increase. These decreases are particularly evident in tropical, arid, and humid snowy climate regions, whereas locations with increasing trends were more prevalent in temperate regions.

To understand our findings, we must first look closely at the factors that could alter the frequency and magnitude of these large streamflow events. These factors are many and varied, and not all of them are related directly to climate. For example, land-use changes, regulated water releases (through dam operations), and the construction of channels or flood levées could all influence streamflow measurements.

We looked into this further by focusing on water catchments that do not have large upstream dams, and have not experienced large changes in forest cover that would alter water runoff patterns. Interestingly, this barely changed our results – we still found more locations with decreasing trends than increasing trends.

The Australian Bureau of Meteorology and similar agencies worldwide have also gone to great lengths to assemble “reference hydrological stations”, in catchments that have experienced relatively limited human change. Studies that used these sorts of stations in Australia, North America and Europe are all still consistent with our findings – namely that most stations show either limited changes or decreases in large streamflow events, depending on their location.

What can we say about future flood risk?

So what about the apparent contradiction between the observed increases in extreme rainfall and the observed decreases in large streamflow events? As noted above, our results don’t seem to be heavily influenced by changes in land use, so this is unlikely to be the primary explanation.

An alternative explanation is that, perhaps counterintuitively, extreme rainfall is not the only cause of floods. If one considers the 2010-11 floods in Queensland, these happened because of heavy rainfall in December and January, but an important part of the picture is that the catchments were already “primed” for flooding by a very wet spring.

Perhaps the way in which catchments are primed for floods is changing. This would make sense, because climate change also can cause higher potential moisture loss from soils and plants, and reductions in average annual rainfall in many parts of the world, such as has been projected for large parts of Australia.

This could mean that catchments in many parts of the world are getting drier on average, which might mean that extreme rainfall events, when they do arrive, are less likely to trigger floods. But testing this hypothesis is difficult, so the jury is still out on whether this can explain our findings.

Despite these uncertainties, we can be confident that the impacts of climate change on flooding will be much more nuanced than is commonly appreciated, with decreases in some places and increases in others.

Your own flood risk will probably be determined by your local geography. If you live in a low-lying catchment close to the ocean (and therefore affected by sea level rise), you’re probably at increased risk. If you’re in a small urban catchment that is sensitive to short sharp storms, there is emerging evidence that you may be at increased risk too. But for larger rural catchments, or places where floods are generally caused by snow melt, the outcome is far harder to predict and certain locations may see a decrease in flooding.

All of this means that a one-size-fits-all approach is unlikely to be suitable if we are to allocate our resources wisely in adjusting to future flood risk. We must also think about the effects of climate change in a broader context that includes changes to land-use planning, investment in flood protection infrastructure, flood insurance, early warning systems, and so on.

Only by taking a holistic view, informed by the best available science, can we truly minimise risk and maximise our resilience to future floods.

Seth Westra, Associate Professor, School of Civil, Environmental and Mining Engineering, University of Adelaide and Hong Xuan Do, PhD candidate in Civil and Environmental Engineering, University of Adelaide

This article was originally published on The Conversation. Read the original article.

Antarctica and Climate Change

It isn’t easy being blue – the cost of colour in fairy wrens

New research shows that fairy-wrens become more cautious as they change colour.
Niki Teunissen, Author provided

Alexandra McQueen, Monash University and Anne Peters, Monash University

Male superb fairy-wrens change colour every year, from dull brown to bright blue. But being blue may be risky if you are a tiny bird that is easily spotted by predators.

Published today, our new study found that male fairy-wrens adjust their risk-taking behaviour after undergoing colour change, becoming more cautious while brightly coloured.

Superb fairy wrens help scientists learn about the evolutionary costs of being beautiful.

Colour and risk

For many males, having beautiful colours is important for attracting choosy females. Researchers think attractive colours come with a cost, so that only the highest quality males can afford to display them. This may be helpful to females looking to select the best mate.

One possible cost of bright colours is increased predation risk, as bright animals are easily seen in their natural habitat. This cost can be dramatic (i.e. being eaten) but may more often involve changes in behaviour to mitigate risk, such as spending more time scanning for predators and being more responsive to perceived threats. Such behaviours are costly because they reduce the time available for foraging and are energetically expensive.

Male superb fairy wren.
Kaspar Delhey, Author provided

A relationship between bright colours, predation risk and cautious behaviour may seem intuitive; however this is difficult to test. This is because different coloured animals may also differ in their age, size, escape tactics and personality, which can influence both their behaviour and actual predation risk.

To address this, we tested whether individuals adjust their response to risk according to changes in their plumage colour.

Fairy-wren antics

Superb fairy-wrens are small, charismatic songbirds. They live in groups with a dominant male and female and, often, several younger males.

These birds are vulnerable to predators such as kookaburras, butcherbirds, currawongs and goshawks. When a group member spots a predator, it gives an alarm call to warn the others. In response, other group members may race for cover, or ignore the alarm and continue about their business.

Male fairy-wrens change colour by replacing dull brown feathers with bright blue, black and indigo ones prior to breeding, turning brown again after the breeding season is complete. Individuals change colour at different times of the year, ranging from the Australian autumn (March-April) to late spring (October).

A male superb fairy-wren in brown plumage (left) and bright blue-and-back plumage (right)
Niki Teunissen and Kaspar Delhey, Author provided

Although female fairy-wrens have a stable, social partner, when egg-laying time comes, they briefly leave their territory under the cover of darkness and “visit” the male who became blue earliest in the year. Many of the females in the surrounding area prefer the same male, who may father around 70% of the offspring in the neighbourhood. These attractive males are blue for longest (remaining blue for 10-12 months of the year) and so may face the greatest risk of predation.

Tracking fairy-wrens

We gave fairy-wrens different coloured leg bands, allowing us to follow the same individuals over time.

Fairy-wren ‘YOB’ with coloured leg bands (Yellow-Orange-Blue)
Alexandra McQueen, Author provided

We compared the behaviour of the same males while they were brown and blue, as well as males that remained brown or blue throughout the study. This meant we could test for the effect of colour on responses to perceived risk while accounting for individual differences and possible seasonal changes in behaviour.

We estimated cautiousness in the birds by testing their response to alarm calls. This involved sneaking up on unsuspecting fairy-wrens in their natural habitat and broadcasting fairy-wren alarm calls from portable speakers.

We used two types of alarms: a low-danger alarm, which warns of a moderate threat, such as a predator that is far away, and a high-danger alarm, which signals an immediate threat.

Low-danger superb fairy-wren alarm call.
Robert Magrath48 KB (download)

High-danger superb fairy-wren alarm call.
Robert Magrath73.1 KB (download)

Costs of being blue

Responses to the low-danger alarm included fleeing for cover, an intermediate response (such as ducking or looking skywards) and no response, when the alarm was ignored. Fairy-wrens fled immediately after hearing the high-danger alarm, but differed in the time taken to return to the open.

We found that fairy-wrens were more cautious while blue; they fled more often after hearing low-danger alarms and took longer to emerge from hiding after fleeing in response to high-danger alarms. Blue fairy-wrens also spent more time scanning their surroundings and less time foraging compared to brown wrens.

This suggests that fairy-wrens perceive themselves to be at a higher risk of predation while bright blue and adjust their behaviour accordingly.

Fairy-wrens are more likely to flee in response to alarms calls while in blue plumage.
Kaspar Delhey, Author provided

Blue decoys?

Intriguingly, fairy-wrens also adjusted their behaviour according to the colour of other wrens in the group. When a blue male was nearby, wrens were less responsive to alarm calls and devoted less time to keeping a look-out.

Perhaps this is because fairy-wrens view blue group members as colourful decoys in the event of an attack. This could occur if predators are biased towards attacking the most conspicuous animal, which reduces the predation risk for surrounding individuals. Brown wrens could also be taking advantage of the greater time blue males spend scanning, allowing them to lower their guard.

Being blue for longest gives males the best chance of attracting females, but they need to be extra careful lest they get eaten before it comes to that.

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Coauthors on this research are Annalise Naimo, Niki Teunissen, Robert Magrath and Kaspar Delhey.

Alexandra McQueen, PhD Candidate in Behavioural Ecology, Monash University and Anne Peters, Associate Professor , Monash University

This article was originally published on The Conversation. Read the original article.

The world’s tropical zone is expanding, and Australia should be worried

‘Tropics’ may conjure images of sun-kissed islands, but the expanding tropical zone could bring drought and cyclones further south.
Pedro Fernandes/Flickr, CC BY-SA

Steve Turton, CQUniversity Australia

The Tropics are defined as the area of Earth where the Sun is directly overhead at least once a year — the zone between the Tropics of Cancer and Capricorn.

However, tropical climates occur within a larger area about 30 degrees either side of the Equator. Earth’s dry subtropical zones lie adjacent to this broad region. It is here that we find the great warm deserts of the world.

Earth’s bulging waistline

Earth’s tropical atmosphere is growing in all directions, leading one commentator to cleverly call this Earth’s “bulging waistline”.

Since 1979, the planet’s waistline been expanding poleward by 56km to 111km per decade in both hemispheres. Future climate projections suggest this expansion is likely to continue, driven largely by human activities – most notably emissions of greenhouse gases and black carbon, as well as warming in the lower atmosphere and the oceans.

If the current rate continues, by 2100 the edge of the new dry subtropical zone would extend from roughly Sydney to Perth.

As these dry subtropical zones shift, droughts will worsen and overall less rain will fall in most warm temperate regions.

Poleward shifts in the average tracks of tropical and extratropical cyclones are already happening. This is likely to continue as the tropics expand further. As extratropical cyclones move, they shift rain away from temperate regions that historically rely upon winter rainfalls for their agriculture and water security.

Researchers have observed that, as climate zones change, animals and plants migrate to keep up. But as biodiversity and ecosystem services are threatened, species that can’t adjust to rapidly changing conditions face extinction.

In some biodiversity hotspots – such as the far southwest of Australia – there are no suitable land areas (only oceans) for ecosystems and species to move into to keep pace with warming and drying trends.

We are already witnessing an expansion of pests and diseases into regions that were previously climatically unsuitable. This suggests that they will attempt to follow any future poleward shifts in climate zones.

I recently drew attention to the anticipated impacts of an expanding tropics for Africa. So what might this might mean for Australia?

IPCC

Australia is vulnerable

Australia’s geographical location makes it highly vulnerable to an expanding tropics. About 60% of the continent lies north of 30°S.

As the edge of the dry subtropical zone continues to creep south, more of southern Australia will be subject to its drying effects.

Meanwhile, the fringes of the north of the continent may experience rainfall and temperature conditions that are more typical of our northern neighbours.

The effects of the expanding tropics are already being felt in southern Australia in the form of declining winter rainfall. This is especially the case in the southwest and — to a lesser extent — the continental southeast.

Future climate change projections for Australia include increasing air and ocean temperatures, rising sea levels, more hot days (over 35℃), declining rainfall in the southern continental areas, and more extreme fire weather events.

For northern Australia, changes in annual rainfall remain uncertain. However, there is a high expectation of more extreme rainfall events, many more hot days and more severe (but less frequent) tropical cyclones and associated storm surges in coastal areas.

Dealing with climate change

Adaptation to climate change will be required across all of Australia. In the south the focus will have to be on adapting to projected drying trends. Other challenges include more frequent droughts, more warm spells and hot days, higher fire weather risk and rising sea levels in coastal areas.

The future growth of the north remains debatable. I have already pointed out the lack of consideration of climate change in the White Paper for the Development of Northern Australia.

The white paper neglects to explain how planned agricultural, mining, tourism and community development will adapt to projected changes in climate over coming decades — particularly, the anticipated very high number of hot days.

For example, Darwin currently averages 47 hot days a year, but under a high carbon emission scenario, the number of hot days could approach 320 per year by 2090. If the north is to survive and thrive as a significant economic region of Australia, it will need effective climate adaptation strategies. This must happen now — not at some distant time in the future.

This requires bipartisan support from all levels of government, and a pan-northern approach to climate adaptation. It will be important to work closely with industry and affected local and Indigenous communities across the north.

These sectors must have access to information and solutions drawn from interdisciplinary, “public good” research. In the face of this urgent need, CSIRO cuts to such research and the defunding of the National Climate Change Adaptation Research Facility should be ringing alarm bells.

As we enter uncharted climate territory, never before has public-good research been more important and relevant.

Steve Turton, Adjunct Professor of Environmental Geography, CQUniversity Australia

This article was originally published on The Conversation. Read the original article.

Huge restored reef aims to bring South Australia’s oysters back from the brink

Mud oysters played a largely unappreciated part in Australia’s history.
Cayne Layton, Author provided

Dominic McAfee, University of Adelaide and Sean Connell, University of Adelaide

The largest oyster reef restoration project outside the United States is underway in the coastal waters of Gulf St Vincent, near Ardrossan in South Australia. Construction began earlier this month. Some 18,000 tonnes of limestone and 7 million baby oysters are set to provide the initial foundations for a 20-hectare reef.

The A$4.2-million project will be built in two phases and should be complete by December 2018. The first phase is the 4-hectare trial currently being built by Primary Industries and Regions South Australia; the second phase will see the reef expand to 20 hectares, led by The Nature Conservancy.

Some of the 18,000 tonnes of limestone destined for the seafloor.
D. McAfee

Just 200 years ago the native mud oyster, Ostrea angasi, formed extensive reefs in the Gulf, along more than 1,500km of South Australia’s coastline. Today there are no substantial accumulations of mud oysters anywhere around mainland Australia, with just one healthy reef remaining in Tasmania.

This restoration project aims to pull our native mud oyster back from the brink of extinction in the wild, and restore a forgotten ecosystem that once teemed with marine life.

More than just seafood

Oysters played a large role in Australia’s colonial history. When European settlers first arrived they had to navigate a patchwork of oyster reefs (also called shellfish reefs) that filled the shallow waters of our temperate bays. These enormous structures could cover 10 hectares in a single patch, providing an easily exploited food resource for the struggling early settlers. Oyster shell was burned to produce lime, and the colony’s first buildings were built with the help of oyster cement.

Collectively, these pre-colonial oyster reefs would have rivalled the geographic extent of the Great Barrier Reef, covering thousands of kilometres of Australia’s eastern and southern coastlines.

The history goes back much further too. For thousands of years oyster reefs fed and fuelled trade among Aboriginal communities. Shell middens dating back 2,000 years attest to the cultural importance of oysters for coastal communities, who ate them in abundance and used their shells to fashion fishhooks and cutting tools.

Health oyster reef in Tasmania.
C. Gillies

The insatiable appetite of the newly settled Europeans for this bountiful resource was devastating. Not only were live oysters harvested for food, but the dead shell foundations that are critical for the settlement of new oysters were scraped from the seabed for lime burning. Armed with bottom-dredges a wave of exploitation spread across the coast, first overexploiting oyster reefs close to major urban centres and then further afield. The combination of the lost hard shell bed and increased sediment runoff from the rapidly altered coastal landscape saw oyster populations crash within a century of colonisation.

Today oyster populations are at less than 1% of their pre-colonial extent in Australia. This is not a unique story – globally it is estimated that 85% of oyster habitat has been lost in the past few centuries, making it one of the most exploited marine habitats in the world.

Today, across much of Australia’s east coast you will see Sydney rock oysters encrusting rocky shores, creating a thin veneer around the edge of our bays and estuaries. On the south coast you occasionally see a solitary mud oyster clinging to a jetty pylon. Many Australians don’t realise that this familiar sight represents a mere shadow of the incredible and largely forgotten ecosystems that oysters once supported.

Oysters are an unsung ecological superhero, with the capacity to increase marine biodiversity, clean coastal waters, enhance neighbouring seagrass, reduce coastal erosion, and even slow the rate of climate change. When oysters cement together, their aggregations form habitat for a great diversity of other invertebrates. A 25cm-square patch of oysters can host more than 1,000 individual invertebrates from a range of different biological groups, in turn providing a smorgasbord for fish.

Restoration site, formerly covered with dense oyster habitat.
D. McAfee

A solitary oyster can filter about 100 litres of water a day, which means that en masse they can function as the “kidneys” of our bays, filtering excess nutrients from the water and depositing them on the seafloor. In doing so, they encourage seagrass growth, while their physical structures help to dissipate wave energy and thus reduce the impact of storm surges.

As if all that weren’t enough, oysters are also a carbon sink, building calcium carbonate shells that are buried in the seafloor after death and eventually compacted to rock, thus helping to prevent carbon dioxide from cycling back into the atmosphere.

Building it back

Restoring oyster reefs has the potential to return these ecosystem services and increase the productivity of our coastal ecosystems. The Gulf of St Vincent project came about through an election promise by the South Australian Government to boost recreational fishing. A collaboration between The Nature Conservancy, Yorke Penninsula Council and the South Australian Government will deliver the reef’s foundations, while my colleagues and I at the University of Adelaide are working to ensure that the restored oysters survive and thrive, and that the reef continues to grow.

Hopefully this is just the beginning for large-scale oyster restoration in Australia, and the lessons learned from this project will guide more restoration projects to improve the health of our oceans. With other restoration projects also underway in Victoria and Western Australia, the tide is hopefully turning for our once numerous oysters.

Dominic McAfee, Postdoctoral researcher, marine ecology, University of Adelaide and Sean Connell, Professor, Ecology, University of Adelaide

This article was originally published on The Conversation. Read the original article.

Explainer: what is tularemia and can I catch it from a possum?

Researchers have found Australia’s first confirmed case of tularemia in a ringtail possum.
Andrew Mercer/flickr, CC BY-NC-SA

John-Sebastian Eden, University of Sydney

Tularemia is a disease that affects humans and other animals. It is caused by infection with the bacterium Francisella tularensis and is commonly spread by biting insects or by direct contact with an infected animal.

Human infection is less common than infection in small animals like rabbits and rodents. But it is important human cases are recognised and diagnosed quickly because without appropriate treatment the disease can be life-threatening.

Our team has recently confirmed its presence in Australia in samples taken from ringtail possums who died in two outbreaks in early 2000.

While this is clearly a newly identified risk to public health, it’s important to recognise how rare the disease is and how well the infection responds to treatment.

How is it transmitted to humans?

Tularemia is a “zoonotic disease”, an animal disease that can be transmitted to humans. The most common way someone might be infected is by being directly exposed to an infected animal through a bite or scratch, or even handling infected tissue, like when hunters skin animals.

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Further reading: First Hendra, now bat lyssavirus, so what are zoonotic diseases?

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Human infections can also occur indirectly from an animal through a biting insect vector, like ticks or deer flies. So, a fly might feed on an infected animal then also bite a human, transferring the bacterium via its mouth parts.

Humans can also catch the disease from animals by coming into contact with environmental sources such as water or soil that have been contaminated by an infected carcass. The bacteria might then infect humans through the eye, or an open wound, or even if digested from contaminated food.

How rare is tularemia in humans?

Fortunately, human cases of tularemia are relatively rare and appear to be limited to the Northern Hemisphere. Yet, even in the US, where the disease is well described, human cases rarely exceed 100-200 a year.

Australia has long been considered tularemia-free. So, it was surprising when, in 2011, two human cases were reported in Tasmania after exposure to ringtail possums.

While diagnostic tests on the patients’ samples suggested an infection with the bacterium, no samples were obtained from the offending possums to corroborate the unusual infection.

More importantly, researchers couldn’t grow and isolate the bacteria from any of the patients’ samples. Follow-up surveys of native animals in the area failed to detect the organism. So, the story of tularemia in Australia had, until recently, remained somewhat of a mystery.

How can I protect myself?

While our study has confirmed the presence of tularemia in Australia and identified ringtail possums as a reservoir for the disease, no-one knows if it’s present in other wildlife along the east coast.

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Further reading: Bites and parasites: vector-borne diseases and the bugs spreading them

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So, to minimise the chances of infection, take care when handling sick, distressed or dead animals. Similarly, when travelling in an area with ticks or other biting insects, wear protective clothing and repellents.

How do I know if I’m infected?

In humans, tularaemia symptoms can vary but typically depend on how someone was exposed.

An ulcer forms at the site of infection, like this one on someone’s hand.
CDC Public Health Image Library/Wikimedia

The most common form of disease in humans is known as ulceroglandular tularemia, which develops after an infected animal or insect bites or wounds you. As the name suggests, you develop a sudden fever, an ulcer forms at the site of infection, and the lymph glands near the wound swell.

Another and perhaps more serious form of the disease is pneumonic tularemia. This can occur when you breathe in bacteria from contaminated dust or aerosols, and your lungs become infected. Symptoms include cough, chest pain and difficulty breathing, and can be difficult to treat.

Yes, it can be treated

While infection can potentially cause severe disease and can kill, timely treatment with commonly available antibiotics should clear the infection. However, it is important the disease is correctly diagnosed as the most effective antibiotics (such as streptomycin) are often different to those used to treat other bacterial skin or wound infections.

There have been no reported cases of humans infecting other humans. While being exposed to someone infected with tularemia might pose some risk, the rarity of the cases and the effectiveness of antibiotic treatments to control the infection minimise this.

Looking to the future

What our study highlights more than anything is the need to investigate wildlife disease to understand potential risks to our environment and our own health.

So, we plan to conduct further surveys of animal and tick-borne diseases to explore undiscovered pathogens that may affect public health or impact our native animal populations.

We are also applying the same technology used to confirm the presence of tularemia in Australian wildlife for the first time to investigate other cold cases of the animal disease world – neglected and undiagnosed animal diseases.

We do this using a powerful technique called “RNA-Seq”, short for RNA sequencing, to analyse samples. With RNA-Seq, there’s no need to know what diseases might be present; researchers sequence all the genetic material in the sample, whether it has come from a host such as a human or animal, or from an infecting organism such as a virus, bacteria, or parasite.

This “metagenome” data is then pieced together and compared to databases containing genome data from previously sequenced pathogens.

Through these studies, we hope to reveal the full diversity of pathogens present in our native wildlife, and particularly, those that sit at the human-animal interface, a fault line that allows microbes to flow from one host to another. Most novel emerging diseases are spill-overs from zoonotic sources, so this research is critical for human health.

John-Sebastian Eden, NHMRC early career fellow, Faculty of Science, University of Sydney

This article was originally published on The Conversation. Read the original article.

Contributions to sea-level rise have increased by half since 1993, largely because of Greenland’s ice

Water mass enters the ocean from glaciers such as this along the Greenland coast.
NASA/JPL-Caltech

John Church, UNSW; Christopher Watson, University of Tasmania; Matt King, University of Tasmania; Xianyao Chen, and Xuebin Zhang, CSIRO

Contributions to the rate of global sea-level rise increased by about half between 1993 and 2014, with much of the increase due to an increased contribution from Greenland’s ice, according to our new research.

Our study, published in Nature Climate Change, shows that the sum of contributions increased from 2.2mm per year to 3.3mm per year. This is consistent with, although a little larger than, the observed increase in the rate of rise estimated from satellite observations.

Globally, the rate of sea-level rise has been increasing since the 19th century. As a result, the rate during the 20th century was significantly greater than during previous millennia. The rate of rise over the past two decades has been larger still.

The rate is projected to increase still further during the 21st century unless human greenhouse emissions can be significantly curbed.

However, since 1993, when high-quality satellite data collection started, most previous studies have not reported an increase in the rate of rise, despite many results pointing towards growing contributions to sea level from the ice sheets of Greenland and Antarctica. Our research was partly aimed at explaining how these apparently contradictory results fit together.

Changes in the rate of rise

In 2015, we completed a careful comparison of satellite and coastal measurements of sea level. This revealed a small but significant bias in the first decade of the satellite record which, after its removal, resulted in a slightly lower estimate of sea-level rise at the start of the satellite record. Correcting for this bias partially resolved the apparent contradiction.

In our new research, we compared the satellite data from 1993 to 2014 with what we know has been contributing to sea level over the same period. These contributions come from ocean expansion due to ocean warming, the net loss of land-based ice from glaciers and ice sheets, and changes in the amount of water stored on land.

Previously, after around 2003, the agreement between the sum of the observed contributions and measured sea level was very good. Before that, however, the budget didn’t quite balance.

Using the satellite data corrected for the small biases identified in our earlier study, we found agreement with the sum of contributions over the entire time from 1993 to 2014. Both show an increase in the rate of sea-level rise over this period.

The total observed sea-level rise is the sum of contributions from thermal expansion of the oceans, fresh water input from glaciers and ice sheets, and changes in water storage on land.
IPCC

After accounting for year-to-year fluctuations caused by phenomena such as El Niño, our corrected satellite record indicates an increase in the rate of rise, from 2.4mm per year in 1993 to 2.9mm per year in 2014. If we used different estimates for vertical land motion to estimate the biases in the satellite record, the rates were about 0.4mm per year larger, changing from 2.8mm per year to 3.2mm per year over the same period.

Is the whole the same as the sum of the parts?

Our results show that the largest contribution to sea-level rise – about 1mm per year – comes from the ocean expanding as it warms. This rate of increase stayed fairly constant over the time period.

The second-largest contribution was from mountain glaciers, and increased slightly from 0.6mm per year to 0.9mm per year from 1993 to 2014. Similarly, the contribution from the Antarctic ice sheet increased slightly, from 0.2mm per year to 0.3mm per year.

Strikingly, the largest increase came from the Greenland ice sheet, as a result of both increased surface melting and increased flow of ice into the ocean. Greenland’s contribution increased from about 0.1mm per year (about 5% of the total rise in 1993) to 0.85mm per year (about 25% in 2014).

Greenland’s contribution to sea-level rise is increasing due to both increased surface melting and flow of ice into the ocean.
NASA/John Sonntag, CC BY

The contribution from land water also increased, from 0.1mm per year to 0.25mm per year. The amount of water stored on land varies a lot from year to year, because of changes in rainfall and drought patterns, for instance. Despite this, rates of groundwater depletion grew whereas storage of water in reservoirs was relatively steady, with the net effect being an increase between 1993 and 2014.

So in terms of the overall picture, while the rate of ocean thermal expansion has remained steady since 1993, the contributions from glaciers and ice sheets have increased markedly, from about half of the total rise in 1993 to about 70% of the rise in 2014. This is primarily due to Greenland’s increasing contribution.

What is the future of sea level?

The satellite record of sea level still spans only a few decades, and ongoing observations will be needed to understand the longer-term significance of our results. Our results also highlight the importance of the continued international effort to better understand and correct for the small biases we identified in the satellite data in our earlier study.

Nevertheless, the satellite data are now consistent with the historical observations and also with projected increases in the rate of sea-level rise.

Ocean heat content fell following the 1991 volcanic eruption of Mount Pinatubo. The subsequent recovery (over about two decades) probably resulted in a rate of ocean thermal expansion larger than from greenhouse gases alone. Thus the underlying acceleration of thermal expansion from human-induced warming may emerge over the next decade or so. And there are potentially even larger future contributions from the ice sheets of Greenland and Antarctica.

The acceleration of sea level, now measured with greater accuracy, highlights the importance and urgency of cutting greenhouse gas emissions and formulating coastal adaptation plans. Given the increased contributions from ice sheets, and the implications for future sea-level rise, our coastal cities need to prepare for rising sea levels.

Sea-level rise will have significant impacts on coastal communities and environments.
Bruce Miller/CSIRO, CC BY

John Church, Chair professor, UNSW; Christopher Watson, Senior Lecturer, Surveying and Spatial Sciences, School of Land and Food, University of Tasmania; Matt King, Professor, Surveying & Spatial Sciences, School of Land and Food, University of Tasmania; Xianyao Chen, Professor, and Xuebin Zhang, Senior research scientist, CSIRO

This article was originally published on The Conversation. Read the original article.

Sludge, snags, and surreal animals: life aboard a voyage to study the abyss

The famous “faceless fish”, which garnered worldwide headlines when it was collected by the expedition.
Rob Zugaro, Author provided

Tim O’Hara, Museum Victoria

Over the past five weeks I led a “voyage of discovery”. That sounds rather pretentious in the 21st century, but it’s still true. My team, aboard the CSIRO managed research vessel, the Investigator, has mapped and sampled an area of the planet that has never been surveyed before.

The RV Investigator in port.
Jerome Mallefet/FNRS

Bizarrely, our ship was only 100km off Australia’s east coast, in the middle of a busy shipping lane. But our focus was not on the sea surface, or on the migrating whales or skimming albatross. We were surveying The Abyss – the very bottom of the ocean some 4,000m below the waves.

To put that into perspective, the tallest mountain on the Australian mainland is only 2,228m. Scuba divers are lucky to reach depths of 40m, while nuclear submarines dive to about 500m. We were aiming to put our cameras and sleds much, much deeper. Only since 2014, when the RV Investigator was commissioned, has Australia had the capacity to survey the deepest depths.

The months before the trip were frantic, with so much to organise: permits, freight, equipment, flights, medicals, legal agreements, safety procedures, visas, finance approvals, communication ideas, sampling strategies – all the tendrils of modern life (the thought “why am I doing this?” surfaced more than once). But remarkably, on May 15, we had 27 scientists from 14 institutions and seven countries, 11 technical specialists, and 22 crew converging on Launceston, and we were off.

Rough seas

Life at sea takes some adjustment. You work 12-hour shifts every day, from 2 o’clock to 2 o’clock, so it’s like suffering from jetlag. The ship was very stable, but even so the motion causes seasickness for the first few days. You sway down corridors, you have one-handed showers, and you feel as though you will be tipped out of bed. Many people go off coffee. The ship is “dry”, so there’s no well-earned beer at the end of a hard day. You wait days for bad weather to clear and then suddenly you are shovelling tonnes of mud through sieves in the middle of the night as you process samples dredged from the deep.

Shifting through the mud of the abyss on the back deck.
Jerome Mallefet/FNRS

Surveying the abyss turns out to be far from easy. On our very first deployment off the eastern Tasmanian coast, our net was shredded on a rock at 2,500m, the positional beacon was lost, tens of thousands of dollars’ worth of gear gone. It was no one’s fault; the offending rock was too small to pick up on our multibeam sonar. Only day 1 and a new plan was required. Talented people fixed what they could, and we moved on.

I was truly surprised by the ruggedness of the seafloor. From the existing maps, I was expecting a gentle slope and muddy abyssal plain. Instead, our sonar revealed canyons, ridges, cliffs and massive rock slides – amazing, but a bit of a hindrance to my naive sampling plan.

But soon the marine animals began to emerge from our videos and samples, which made it all worthwhile. Life started to buzz on the ship.

Secrets of the deep

Like many people, scientists spend most of their working lives in front of a computer screen. It is really great to get out and actually experience the real thing, to see animals we have only read about in old books. The tripod fish, the faceless fish, the shortarse feeler fish (yes, really), red spiny crabs, worms and sea stars of all shapes and sizes, as well as animals that emit light to ward off predators.

A spiny red lithodid crab.
Rob Zugaro/Museums Victoria

The tripod fish uses its long spines to sit on the seafloor waiting for the next meal.
Rob Zugaro/Museums Victoria

The level of public interest has been phenomenal. You may already have seen some of the coverage, which ranged from the fascinated to the amused – for some reason our discovery of priapulid worms was a big hit on US late-night television. In many ways all the publicity mirrored our first reactions to animals on the ship. “What is this thing?” “How amazing!”

The important scientific insights will come later. It will take a year or so to process all the data and accurately identify the samples. Describing all the new species will take even longer. All of the material has been carefully preserved and will be stored in museums and CSIRO collections around Australia for centuries.

Scientists identifying microscopic animals onboard.
Asher Flatt

On a voyage of discovery, video footage is not sufficient, because we don’t know the animals. The modern biologist uses high-resolution microscopes and DNA evidence to describe the new species and understand their place in the ecosystem, and that requires actual samples.

So why bother studying the deep sea? First, it is important to understand that humanity is already having an impact down there. The oceans are changing. There wasn’t a day at sea when we didn’t bring up some rubbish from the seafloor – cans, bottles, plastic, rope, fishing line. There is also old debris from steamships, such as unburned coal and bits of clinker, which looks like melted rock, formed in the boilers. Elsewhere in the oceans there are plans to mine precious metals from the deep sea.

Rubbish found on the seafloor.
Rob Zugaro/Museums Victoria

Second, Australia is the custodian of a vast amount of abyss. Our marine exclusive economic zone (EEZ) is larger than the Australian landmass. The Commonwealth recently established a network of marine reserves around Australia. Just like National Parks on land, these have been established to protect biodiversity in the long term. Australia’s Marine Biodiversity Hub, which provided funds for this voyage, as been established by the Commonwealth Government to conduct research in the EEZ.

The newly mapped East Gippsland Commonwealth Marine Reserve, showing the rugged end of the Australian continental margin as it dips to the abyssal plain. The scale shows the depth in metres.
Amy Nau/CSIRO

Our voyage mapped some of the marine reserves for the first time. Unlike parks on land, the reserves are not easy to visit. It was our aim to bring the animals of the Australian Abyss into public view.

We discovered that life in the deep sea is diverse and fascinating. Would I do it again? Sure I would. After a beer.

Tim O’Hara, Senior Curator of Marine Invertebrates, Museum Victoria

This article was originally published on The Conversation. Read the original article.