Best of our wild blogs: 29 Nov 16

Get Crafty This December 2016 at LKCNHM
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How much coral has died in the Great Barrier Reef’s worst bleaching event?

James Cook University The Conversation AU 29 Nov 16;

Two-thirds of the corals in the northern part of the Great Barrier Reef have died in the reef’s worst-ever bleaching event, according to our latest underwater surveys.

On some reefs in the north, nearly all the corals have died. However the impact of bleaching eases as we move south, and reefs in the central and southern regions (around Cairns and Townsville and southwards) were much less affected, and are now recovering.

In 2015 and 2016, the hottest years on record, we have witnessed at first hand the threat posed by human-caused climate change to the world’s coral reefs.

Heat stress from record high summer temperatures damages the microscopic algae (zooxanthellae) that live in the tissues of corals, turning them white.

After they bleach, these stressed corals either slowly regain their zooxanthellae and colour as temperatures cool off, or else they die.

The Great Barrier Reef bleached severely for the first time in 1998, then in 2002, and now again in 2016. This year’s event was more extreme than the two previous mass bleachings.

Surveying the damage

We undertook extensive underwater surveys at the peak of bleaching in March and April, and again at the same sites in October and November. In the northern third of the Great Barrier Reef, we recorded an average (median) loss of 67% of coral cover on a large sample of 60 reefs.

The dieback of corals due to bleaching in just 8-9 months is the largest loss ever recorded for the Great Barrier Reef.

To put these losses in context, over the 27 years from 1985 to 2012, scientists from the Australian Institute of Marine Science measured the gradual loss of 51% of corals on the central and southern regions of the Great Barrier Reef.

They reported no change over this extended period in the amount of corals in the remote, northern region. Unfortunately, most of the losses in 2016 have occurred in this northern, most pristine part of the Great Barrier Reef.


ARC Centre of Excellence for Coral Reef Studies

Bright spots

The bleaching, and subsequent loss of corals, is very patchy. Our map shows clearly that coral death varies enormously from north to south along the 2,300km length of the Reef.

The southern third of the Reef did not experience severe heat stress in February and March. Consequently, only minor bleaching occurred, and we found no significant mortality in the south since then.

In the central section of the Reef, we measured widespread but moderate bleaching, which was comparably severe to the 1998 and 2002 events. On average, only 6% of coral cover was lost in the central region in 2016.

The remaining corals have now regained their vibrant colour. Many central reefs are in good condition, and they continue to recover from Severe Tropical Cyclones Hamish (in 2009) and Yasi (2011).

In the eastern Torres Strait and outermost ribbon reefs in the northernmost part of the Great Barrier Reef Marine Park, we found a large swathe of reefs that escaped the most severe bleaching and mortality, compared to elsewhere in the north. Nonetheless, 26% of the shallow-water corals died.

We suspect that these reefs were partially protected from heat stress by strong currents and upwelling of cooler water across the edge of the continental shelf that slopes steeply into the Coral Sea.

For visitors, these surveys show there are still many reefs throughout the Marine Park that have abundant living coral, particularly in popular tourism locations in the central and southern regions, such as the Whitsundays and Cairns.

Darkspots

The northern third of the Great Barrier Reef, extending 700km from Port Douglas to Papua New Guinea, experienced the most severe bleaching and subsequent loss of corals.

On 25% of the worst affected reefs (the top quartile), losses of corals ranged from 83-99%. When mortality is this high, it affects even tougher species that normally survive bleaching.

However, even in this region, there are some silver linings. Bleaching and mortality decline with depth, and some sites and reefs had much better than average survival. A few corals are still bleached or mottled, particularly in the north, but the vast majority of survivors have regained their colour.

What will happen next?

The reef science and management community will continue to gather data on the bleaching event as it slowly unfolds. The initial stage focused on mapping the footprint of the event, and now we are analysing how many bleached corals died or recovered over the past 8-9 months.

Over the coming months and for the next year or two we expect to see longer-term impacts on northern corals, including higher levels of disease, slower growth rates and lower rates of reproduction. The process of recovery in the north – the replacement of dead corals by new ones – will be slow, at least 10-15 years, as long as local conditions such as water quality remain conducive to recovery.

As global temperatures continue to climb, time will tell how much recovery in the north is possible before a fourth mass bleaching event occurs.

This article was co-authored by David Wachenfeld, Director for Reef Recovery at the Great Barrier Reef Marine Park Authority.


Great Barrier Reef scientists confirm largest die-off of corals recorded
Higher sea temperatures have led to the worst bleaching event on record, new study finds, with coral predicted to take up to 15 years to recover
Guardian staff and agencies The Guardian 28 Nov 16;

A new study has found that higher water temperatures have ravaged the Great Barrier Reef, causing the worst coral bleaching recorded by scientists.

In the worst-affected area, 67% of a 700km swath in the north of the reef lost its shallow-water corals over the past eight to nine months, the Australian Research Council Centre of Excellence for Coral Reef Studies based at James Cook University study found.

“Most of the losses in 2016 have occurred in the northern, most-pristine part of the Great Barrier Reef,” Prof Terry Hughes said. “This region escaped with minor damage in two earlier bleaching events in 1998 and 2002, but this time around it has been badly affected.”

Great Barrier Reef: diving in the stench of millions of rotting animals
The southern two-thirds of the reef escaped with minor damage, Hughes said. This part was protected from the rising sea temperatures because of cooler water from the Coral Sea.

Scientists expect that the northern region will take at least 10 to 15 years to regain the lost corals but are concerned a fourth bleaching event could interrupt the slow recovery.

The dire assessment of the reef’s health comes as the Australian government is due to report to Unesco’s world heritage committee on its handling of the reef.

After the federal government submits the report Unesco will decide whether to again consider listing the Great Barrier Reef on its “list of world heritage in danger”.

The government will need to report on how it has funded and implemented its Reef 2050 long-term sustainability plan, as well as how the bleaching event has affected the reef.

Since it last considered including the Great Barrier Reef on its list, the reef has undergone the worst bleaching event in recorded history. According to government agencies, 22% of the reef was killed in one hit, as unusually warm waters bleached and killed the coral.

Climate change poses such a threat to the reef that the former head of the Great Barrier Reef Marine Park Authority has called for a ban on all new coalmines in Australia to protect the reef from climate change.

Graeme Kelleher, who was the first chief executive of the authority, a position he held for 16 years, said: “Australia cannot have a healthy Great Barrier Reef and a continuing coal industry.

“I love the reef and I have worked to preserve it since 1979; I will oppose anything that threatens to destroy it,” he said.


Great Barrier Reef suffered worst bleaching on record in 2016, report finds
Hywel Griffith BBC News 28 Nov 16;

Higher water temperatures in 2016 caused the worst destruction of corals ever recorded on Australia's Great Barrier Reef, a study has found.

Some 67% of corals died in the reef's worst-hit northern section, the ARC Centre of Excellence for Coral Reef Studies report said.

The situation was better in the central section, where 6% perished, while the southern reef is in good health.

But scientists warn recovery could be difficult if climate change continues.

Coral bleaching happens when water temperatures rise for a sustained period of time.

In February, March and April, sea surface temperatures across the Great Barrier Reef were the hottest on record, at least 1C higher than the monthly average.

"Some of the initial mortality was down to heat stress," said study leader Professor Terry Hughes.

"The coral was cooked."

How bleaching occurs

Far more has been lost through gradual starvation, after the coral expelled the colourful algae zooxanthella, which turns sunlight into food.

This is what leads to the white, skeletal appearance of the coral, which is left without its main source of energy.

The study also found that the coral which survived the bleaching have now come under greater threat from predators such as snails and crown of thorns starfish.

This year's mass bleaching was the worst-ever recorded on the Great Barrier Reef, following two previous events in 1998 and 2002.

Professor Hughes is certain that the increased water temperature is the result of carbon emissions, and warns that climate change could bring annual bleaching within 20 years.

"Most of the losses in 2016 have occurred in the northern, most pristine part of the Great Barrier Reef," he said.

"This region escaped with minor damage in two earlier bleaching events in 1998 and 2002, but this time around it has been badly affected."

Where is the damage?

One of the worst-hit areas is around Lizard Island in Far North Queensland, where around 90% of the coral has died.

Dr Andrew Hoey, whose team charted the area, said the impact was far worse than feared after an initial survey in April.

"It's devastating to get in the water somewhere you've been coming for almost 20 years, and it's just knocked it on its head," he said.

"There's very little coral cover left there. It was dominated by the acropora - the branching corals - but we lost most of them."

Lizard Island is home to a research station, where scientists from across the world have come for decades to study marine life
One of its directors, Dr Anne Hogget, said this was by far the worst event to hit the Great Barrier Reef since she started working there in 1990.

"We had bleaching here in 2002," she said. "We thought this was bad at the time, but this has blown it completely out of the water."

She is hopeful that the reef is capable of recovery, but fears it may not be give an opportunity, as sea temperatures continue to rise.

"The trajectory is not good," Dr Hogget explained.

"We keep pumping carbon dioxide into the atmosphere, and this happened absolutely because of that."

What happens next?

On the central and southern parts of the Great Barrier Reef, where bleaching was not as prevalent, there is concern that it has been misreported, with one magazine even publishing an obituary of the reef earlier this year.

Tourism operators like Michael Healey from the Quicksilver Group are keen to point out that many sites were unaffected, but there is concern for the reef's long term health.

"Without the Great Barrier Reef, we wouldn't survive," he said.

"So it is absolutely of the utmost importance that we ensure that our politicians and everyone else in our community and around the world are doing what they can."

The Australian Government has published a long-term sustainability plan for the reef, and pledged financial support for research into coral bleaching.

The 2050 plan identifies the need to help make the reef more resilient to climate change in the future, while trying to lower carbon emissions.

Mr Healy argued even those not financially involved had a stake in the reef.

"I'd say every human on the planet does," he said.

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Marine disease likely to follow Great Barrier Reef coral bleaching

Cornell University Science Daily 28 Nov 16;

Higher water temperatures in 2016 caused the worst destruction of corals ever recorded on Australia's Great Barrier Reef, report experts. And this may be followed by devastating outbreaks of infectious disease, they say.
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Drew Harvell, a professor of ecology and evolutionary biology, is widely recognized for her work on marine diseases -- specifically, the ecology and evolution of coral resistance to disease as well as evaluating the impacts of a warming climate on coral reef ecosystems. Harvell says the ARC Centre of Excellence for Coral Reef Studies report showing that higher water temperatures in 2016 caused the worst destruction of corals ever recorded on Australia's Great Barrier Reef may be followed by devastating outbreaks of infectious disease.

Harvell says, "Although the Great Barrier Reef was badly hit, the epicenter of this 2016 event is actually in the middle of the Indo-pacific, at Palmyra atoll and Kiribati where temperatures reached four degrees about the seasonal baseline for over a month. Over 90 percent of corals died on many of those reefs.

"This is the worst bleaching event of the northern great barrier reef. Mid and southern sections were also hit with a 2002 event that caused mass bleaching and outbreaks of infectious disease. We typically do see outbreaks of disease following the bleaching events, because of the double whammy of the corals being stressed and warm temperatures favor infectious microorganisms.

"Outside magazine published an article called 'An Obituary for the Great Barrier Reef.' The event was bad, but the central and southern regions of the Great Barrier Reef are quite healthy, so that article was over-stated. You don't call a forest dead just because 50 percent of the trees are dead, but it is an extreme event.

"It is useful to realize this is the third straight year in a row of record-breaking temperature. Each year from 2014-2016 was successively the warmest year on record, assuming this year will once again break records and now be the warmest year on record."

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Thailand: Climate change 'threatens fight against illegal fishing'

Cod Satrusayang Reuters 28 Nov 16;

Climate change threatens to undermine Thailand's efforts to combat illegal fishing and avoid a potential European Union ban on exports by the multi-billion dollar seafood industry, environmental groups say.

They warn that climate change is slowing the recovery of fish stocks in traditional fishing grounds, prompting boats to venture outside Thai waters in search of fish.

“Overfishing plays a major role in the decimation of the fish stock in the Gulf of Thailand and the Andaman Sea, but climate change is just as big a threat,” said Suchana Chavanich, a marine biologist at Chulalongkorn University.

“Warmer oceans mean that fish don’t grow to their full length. Coral bleaching caused by climate change means fish nurseries and their food sources are also under threat,” Suchana said.

Thailand's fish stocks peaked in 2006 at 856,212 tonnes of fish caught in the Gulf of Thailand, according to One Shared Ocean, a group that monitors marine issues.

Four years later it was down to 617,568 tonnes, the last year for which the group has data.

The EU issued a "yellow card" to Thailand in April 2015, warning the country should clean up its poorly regulated fishing industry or face a ban on seafood exports.

Thailand is the world's third-largest seafood exporter, shipping $7 billion worth of fish and seafood products in 2013, according to fisheries department data.

Exports to the EU were 481 million euros ($511 million) last year, EU figures show.

Since the EU "yellow card", the Thai government said it has registered most of its fishing fleet and banned ships fitted with push nets and bottom trawling equipment from going to sea.

As a result, more than 3,500 fishing boats have been unable to leave port for at least a year, according to the Thai Overseas Fisheries Association.

Earlier this month, the last of 48 boats seized during operations against illegal fishing were sunk off the Thai coast in an effort to create artificial coral reefs for tourism.

The EU said it is working with Thailand on implementing an action plan and no deadline has been set for a decision. “The dialogue with the Thai authorities is ongoing,” Enrico Brivio, spokesperson for Environment, Maritime and Fisheries, said in an emailed statement.

While the government has sought to avoid an EU ban, it has not done enough to address the effects of climate change on marine aquaculture, said Anchalee Pipattanawattanakul, an ocean researcher at Greenpeace Southeast Asia.

"Any recovery made by fish stocks from the government's new illegal fishing initiatives are threatened in the long term by warming oceans," Anchalee said.

Officials at the Department of Fisheries said climate change was an issue for the cabinet and parliament to address.

Meanwhile, the fishing industry is skeptical about the government's assurances that the measures it has introduced to combat illegal fishing will lead to a recovery in fish stocks.

More than 300,000 people are employed in Thailand's seafood sector, many of them migrant workers from neighboring countries.

"A lot of the fishermen have come to me for advice about changing industries and what other things they can do," said Abhisit Techanitisawad, President of the Thai Overseas Fisheries Association.

"They just don't see their long term future within this industry."

(Editing by Darren Schuettler)

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India’s grand plan to create world’s longest river set to go

TV Padma New Scientist 28 Nov 16;

Engineering projects don’t come any bigger than this. If India’s prime minister, Narendra Modi, gets his way, work could soon begin on a project to link large rivers in the Himalayas and Deccan Peninsula via 30 mega-canals and 3000 dams.

When the work is finished the water network will be twice the length of the Nile, the world longest river, and it will be able to divert water from flood-prone areas to those vulnerable to drought.

But geologists and ecologists in India question the science behind the Inter Linking of Rivers (ILR) scheme. If it goes ahead it might lead to ecological disasters and coastal erosion that would threaten livelihoods and endanger wildlife.

And yet New Scientist has learned from the officials close to the project that work on the pilot link is likely to “start any time soon”, with final clearance from the ministry of environment and forests expected imminently.

Water network

Versions of the ILR scheme date back more than 60 years to the days of British rule in India. In its latest incarnation the plan is to link 14 rivers in north India and 16 in the western, central and southern parts of the country, creating a water network some 12,500 kilometres long. The idea is to reduce droughts and floods and create 35 million hectares of arable land in the process, as well as the means to generate 34,000 megawatts of hydropower.

This project is backed by Narendra Modi, who became the country’s prime minister in 2014. Since then India’s National Water Development Agency has completed detailed project reports for three key initial river links – the pilot link between Ken and Betwa rivers in northern and central India; Daman Ganga and Pinjal rivers in western India; and Par and Tapti rivers in western and central India. A feasibility report of a fourth link between three Himalayan rivers – Manas, Teesta and Ganges – is in the final stages of preparation.

But many researchers question the science behind the scheme. They say there isn’t a simple division between river basins that carry too little and too much water – and that climate change has triggered changes in rainfall patterns with unpredictable knock-on effects on water flow.

They argue that it would be unwise to set in stone a vast new canal network at a time of dramatic environmental change.

Changing climate

A study published in July builds on this. Climate modelling once predicted that India’s dry areas will become drier and its wet areas wetter, but this is no longer the case.

A team of scientists from the Indian Institute of Technology in Bombay and Madras found a significant decrease in the monsoon rainfall over major water surplus river basins in India. The team’s computer simulations showed that the water yield in surplus river basins is decreasing but it is increasing in deficit basins.”What may appear as water deficient today may become water surplus in the future due to climate change,” says study author Sachin Gunthe at Indian Institute of Technology, Madras. “So, how do you justify inter-linking?”

Geologists are concerned, too. Over the millennia India’s landscape has gradually evolved with the natural flow of water. “Most rivers are fed by monsoon rains and have built large floodplains and deltas over the years,” says Vedharaman Rajamani at the Jawaharlal Nehru University in New Delhi. “Pushing rivers around through ILR disrupts the supply of sediments and nutrients downstream.”

This could negatively affect agriculture, as farmlands have been built over centuries in floodplains and near river deltas. “Rivers recharge aquifers near farmland,” Rajamani says. “Besides, rivers are critical to freshwater biodiversity, including fish, and carry nutrients to marine life.”

Good side of floods
What’s more, a central target of the ILR scheme – to make flooding in some parts of India a thing of the past – ignores the very real value of flooding. For one thing, it carries huge volumes of silt that can reduce coastal erosion.

“A river is not just a natural pipe through which water flows,” says geologist Chittenipattu Rajendran at the Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore. “It carries deposits and sediments. Dams trap sediments that are critical to habitats downstream.”

Natural flooding also helps recharge supplies of freshwater below India’s floodplains and deltas. Without that sporadic influx from floods, salt water gradually intrudes into groundwater supplies in land. “Desiccation and desertification follow,” says Rajamani. Decreased sedimentation also leads to coastal erosion, he adds.

Rajamani says the presence of excess fresh water in the Bay of Bengal delta is especially crucial, as it helps create and maintain a layer of low salinity in the bay, which is one of the several complex, interlinked factors that influence the onset of the Indian summer monsoon. Artificially manipulating the natural system could disrupt the monsoon rainfall in the region, he says.

Rajendran says that the huge amount of water in dams would increase the water pressure in the cracks and push on crust below, possibly increasing the risk of earthquakes in the already quake-prone Himalayas.

A grand distraction?
Sunita Narain, director of Delhi-based NGO, the Centre for Science and Environment, has in the past described river linking as a “grand distraction” from other pressing problems, including environment degradation.

She thinks the ILR scheme will mean building vast reservoirs to control and store water. Those reservoirs will displace hundreds of thousands of people, she says – claiming the Indian government’s track record in resettling people displaced by such projects has been poor.

Ecologists are concerned too. A pilot project in the ILR scheme – the Ken-Betwa link – would be built at the cost of destroying an estimated 4100 hectares of forest. This might include 58 square kilometres of the Panna Tiger Reserve – 10 per cent of the reserve’s area. And yet it got the official approval in September.

The government, however, has stayed dedicated to the idea. Interlinking rivers is an attempt to boost water supply to the needy states, says Vijay Goel, junior minister for water resources.

But while the project looks grand on paper whether it turns out to be a success or a disaster remains to be seen.

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Shrinking glaciers cause state-of-emergency drought in Bolivia

Climate News Network: Three main dams supplying water to La Paz and El Alto are no longer fed by Andean glaciers and have nearly run dry
Jan Rocha for Climate News Network, part of the Guardian Environment Network The Guardian 28 Nov 16;

The government of Bolivia, a landlocked country in the heart of South America, has been forced to declare a state of emergency as it faces its worst drought for at least 25 years.

Much of the water supply to La Paz, the highest capital city in the world, and the neighbouring El Alto, Bolivia’s second largest city, comes from the glaciers in the surrounding Andean mountains.

But the glaciers are now shrinking rapidly, illustrating how climate change is already affecting one of the poorest countries in Latin America.

The three main dams that supply La Paz and El Alto are no longer fed by runoff from glaciers and have almost run dry. Water rationing has been introduced in La Paz, and the poor of El Alto – where many are not yet even connected to the mains water supply – have staged protests.

The armed forces are being brought in to distribute water to the cities, emergency wells are being drilled, and schools will have to close two weeks ahead of the summer break.

President Evo Morales sacked the head of the water company for not warning him earlier of the dangerous situation, but the changes produced by global warming have been evident for some time.

Shrinking snowline

A recent report by the Stockholm Environment Institute (SEI) says: “Temperatures in the region have risen by 0.5C (0.9F) in the period 1976 to 2006, and the people of La Paz and El Alto can observe evidence of climate change in the form of the shrinking snowline in the mountains above them.

Low water levels at the Milluni Zongo reservoir near La Paz, Bolivia.
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Low water levels at the Milluni Zongo reservoir near La Paz, Bolivia. Photograph: Bloomberg via Getty Images
One glacier on Chacaltaya mountain – which rises above El Alto and which once hosted the world’s highest ski resort – has already completely disappeared. And the two Tuni-Condoriri glaciers that provide water for El Alto and La Paz lost 39% of their area between 1983 and 2006 – at a rate of 0.24 sq km per year.”

The SEI says that if the regional and global climate models that predict a two-degree rise in temperatures by 2050 are right, many small glaciers will completely disappear, while others will shrink dramatically.

It warns: “Glaciers are estimated to provide 20% to 28% of water for El Alto and La Paz. Therefore glacier loss will have a considerable impact, which will be felt particularly during the dry season, when glacial water provides the majority of urban water.

“The glaciers and mountain water systems also support agriculture, power generation and natural ecosystems throughout the region.”

The problem is exacerbated in El Alto, a sprawling settlement of more than a million people who have migrated from the countryside.

The city’s population grew by at least 30% between 2001 and 2012, and the city’s land area has rapidly expanded by 144% in the last decade, spreading into the flat open countryside to the south and west. By 2050, the population is expected to double to two million people.

The SEI believes that one of the causes of this increased influx into the city will be climate change. It says: “Evidence from El Alto’s history indicates that the fastest periods of population growth coincided with droughts, floods and bad harvests associated with the meteorological phenomena of El Niño and La Niña.

“The years 1985 to 1987, when migration into El Alto reached heights of 65,000 new immigrants, were also years of poor harvests.”

Supply outstripped

By 2009, demand for water in El Alto had already outstripped supply, and that supply is now increasingly under threat as climate change melts the glaciers.

Bolivia cannot rely on new sources to resolve its water crisis, given both the costs and potential range of climate change impacts. So one of the country’s most critical challenges in coming years will be to plan and implement strategies for managing water under uncertain climate conditions.

Conservation and recycling methods, the SEI says, will be needed to build the resilience of Bolivian cities’ water systems to climate change.

The cities will also need to find ways of reducing water consumption, especially from industries and commercial enterprises, but also from the profligacy of a small number of rich domestic consumers.

The SEI paper recommends community participation in developing strategies and decision-making on the management of water resources. But, at the moment, the only role for those affected communities is that of protest.

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