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The songs of trees
A harbinger of spring in the high places
On a cold day on Cairn Gorm there was little to occupy the attention – until the appearance of a ring ouzel signalled the return of spring
Go-back, go-back, go-back! A red grouse was calling just above the car park, at the bottom of the path to the summit of Cairn Gorm. For a moment I was tempted to heed his advice and retreat to the nearby café.
But my children were uncharacteristically enthusiastic about the idea of walking up the mountainside; buoyed, no doubt, by the prospect of playing in the snow. And so we headed up the path.
Continue reading...Great Barrier Reef tourism: caught between commerce and conservation alarm
More people than ever are coming to see the reef and those who make a living showing it off want the world to know it’s still a natural wonder. But they worry about its future, and that of their 64,000-strong industry
In the dark clouds gathering over the future of the Great Barrier Reef, there has been a small silver lining for the people who make their living showcasing the natural wonder.
When the reef was rocked by an unprecedented second mass bleaching event in the space of a year, the coral hardest-hit by heat stress lay mostly in the tourist-heavy latitudes between Cairns and Townsville.
Continue reading...Death metal: how nickel played a role in the world's worst mass extinction
Around 250 million years ago, life on Earth nearly came to an end, in a mass extinction between the Permian and Triassic periods known as the Great Dying. Some 90% of the species in the oceans and 70% of vertebrate families on land were killed, and the great marine life experiment of the Palaeozoic era was brought to a halt.
What does this have to do with nickel? Well, as part of my recent work as a mining geologist, which involves studying the world’s most valuable nickel ore deposits in Siberia, I uncovered evidence of a link between ore genesis – how the nickel got there – and the onset of the Great Dying. These results were recently published in the Proceedings of the National Academy of Sciences.
It was an exceedingly strange world 250 million years ago, and finding the culprits for the world’s worst mass extinction is like putting together a puzzle.
Earth, fire, waterThis catastrophic episode was triggered by several different events, which in turn killed the world’s species in different ways: declining oxygen levels in the ocean, massively rising temperatures, and a possible meteor impact.
One of these trigger events involved a major jolt to the carbon cycle, which had dramatic climate effects. Some scientists think the temperature of the upper level of the world’s oceans and rivers increased from 21℃ to 38℃ in the late Smithian era (250.7 million years ago).
This shift in the carbon cycle has been attributed to a major burst of activity of deep marine colonies of Archaea methanosarcina, relatives of bacteria. These colonies had acquired a new way of getting energy from their environment. In much the same way as human bodies get energy from food, producing carbon dioxide in the process, these organisms got energy from transforming organic carbon into methane.
The archaea colonies were normally limited by the amount of nickel in the oceans, but for some reason, 250 million years ago, nickel seems to have been in abundant supply compared with today.
At the same time as the Great Dying, in an area on Earth that we now call Siberia, an astronomical amount of lava generated in the guts of the Earth erupted over an area the size of Europe. This province is the host to the Noril’sk ore deposits, the Earth’s most valuable source of mined nickel.
Scientists previously thought that nickel released into the atmosphere could explain the glut of marine nickel 250 million years ago. But how could nickel get into the air? This is where our work comes in.
Volcanoes and champagneLet’s take a step back: how do nickel ore deposits form from molten rock (or magma)? Magma rich in nickel needs to come all the way to shallow depths beneath volcanoes, where it becomes enriched with sulfur, and forms liquid sulfide droplets.
The volcanic plumbing system then acts as a smelter. The sulfide liquid droplets scrub the nickel out of the magma. Ore deposits form when the sulphide droplets finally sink and accumulate at the bottom of the magma under the volcanoes. The nickel never reaches the surface – making it hard to explain how so much nickel got into the atmosphere.
A previous paper by our group showed that when liquid sulfide droplets and gas bubbles form together in the same magma they have a strong tendency to stick together. So, if there is a gas present, sulfide droplets can rise to the top of the magma chambers, taking the metals with them.
In a big eruption, like the one that produced the Siberian lava, the pressure drops, and it’s like opening a bottle of champagne. A swarm of bubbles forms and floats to the top. The liquid sulfide droplets hitch a ride like baskets beneath hot air balloons.
We think that this “bubble riding” is how nickel got from the bottom of the Noril’sk magma all the way to the surface and into volcanic gases and aerosols.
During our recent studies of the Noril’sk nickel ores, we found the smoking gun: we used 2D and 3D X-ray imaging to show nickel-rich sulfide droplets physically attached to former gas bubbles, frozen in the ore.
We combined this observation with simple thermodynamic models to show that this transport mechanism greatly increases the amount of nickel content in volcanic aerosols.
The perils of methaneThe Noril’sk nickel deposits are unique. They are the only known place where nickel had a direct path to the atmosphere. Explosive eruptions helped to release colossal amounts of gas into the air.
During these massive gas episodes, our sulfide-carrying champagne bubbles transported large amount of nickel and tipped it into the atmosphere to feed the blooming archaea, playing an important role in the Great Dying.
The Noril'sk ores formed in a freak event, but if the broader hypothesis is correct they hold a lesson for life on Earth: release large amounts of methane into the atmosphere at enormous peril.
Under normal circumstances, volcanic eruptions are a relatively minor source of methane in the atmosphere, but lethal time bombs exist in methane frozen into permafrost, much of it, coincidentally, to be found in the tundra wastelands covering the Siberian lava fields. Here, melting of the permafrost releases bubbles of methane into the atmosphere, creating a climate changing feedback loop – to potentially devastating effect.
Margaux Le Vaillant would like to acknowledge the contribution of Steve Barnes, James Mungall and Emma Mungall.
![The Conversation](https://counter.theconversation.edu.au/content/74754/count.gif)
Margaux Le Vaillant does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond the academic appointment above.
Theresa May urged to honour climate and wildlife commitments
Celebrities and pressure groups warn UK prime minister against entering into ‘environmental race to the bottom’ to secure post-Brexit trade deals
Leading environmental campaigners have warned the government against scaling back on commitments to tackle climate change and end the illegal market in wildlife in order to secure post-Brexit trade deals.
Greenpeace, WWF, Friends of the Earth and high-profile figures including Andy Murray and Will Young are among those who have signed a joint letter to the prime minister urging Theresa May not to engage in an “environmental race to the bottom” after withdrawal from the EU.
Continue reading...Urban foxes number one for every 300 residents, study suggests
Researchers estimate there are 150,000 urban foxes in England, with Bournemouth having the highest concentration
The number of urban foxes in England has quadrupled in the past 20 years, according to a study that estimates there are nearly 150,000 in England, or about one for every 300 urban residents.
While the number of foxes is declining overall in the UK, the study by Brighton and Reading universities has found that Bournemouth tops the charts with the highest concentration of urban foxes in the UK at 23 per square kilometre.
Continue reading...22,000 years of history evaporates after freezer failure melts Arctic ice cores
Around 13% of cache of ice cylinders extracted from glaciers in Canadian Arctic exposed to high heat in new storage facility at University of Alberta
Within them sits some 80,000 years of history, offering researchers tantalising clues about climate change and the Earth’s past. At least that was the case – until the precious cache of Arctic ice cores was hit by warming temperatures.
A freezer malfunction at the University of Alberta in Edmonton has melted part of the world’s largest collection of ice cores from the Canadian Arctic, reducing some of the ancient ice into puddles.
Continue reading...Green groups warn of 'race to the bottom'
The eco guide to bike-sharing
Cycling has the power to transform urban transport. But access to bikes is key to getting more of us on to two wheels
Imagine the huge improvement in air quality if we shifted to pedal power. In Groningen, in the Netherlands, almost two-thirds of trips are made by bike, making it one of the most cycle-friendly cities in the world. It’s no accident that the Dutch city also has great air quality. The UK manages a meagre 2% cycling rate overall. And we all know about the air quality here.
If, by the way, your wheels are redundant, please pass them on to the Bike Project to match with someone who desperately wants one.
Continue reading...Great moments from the ‘most exciting time in nature’s calendar’
Perched on the telegraph wires in my Somerset village, is a swallow – all the way back from its winter quarters in Africa. In my back garden, orange-tip and small tortoiseshell butterflies are searching for nectar. And everywhere I look, spring foliage is filling the countryside with green.
This has been a vintage spring for wildlife watchers. Thanks to a spell of fine, settled weather at the end of March and the beginning of April, bluebells carpet forest floors, the dawn chorus is reaching its peak, and living creatures – from natterjack toads to great crested newts, bumblebees to badgers – are out in force. What more could we wish for on Easter weekend?
Continue reading...The wildlife-friendly hedge: Country diary 100 years ago
Originally published in the Manchester Guardian on 21 April 1917
Surrey, April 19
The bush harrow has been at work in the meadows, and light rain, dewing the grass tops, glistens even under the clouds along broad green paths which extend from end to end of the field. The blackbirds have been very active these past few days, scurrying noisily about the hedges and piping in regular notes up among the trees. There is a nest in a hollow of the hedge bottom, built where a thorn begins to branch out from the roots, plastered inside as if with a delicate tool and then lined with tops of dead grasses and a few driblets of wool which have clung to the hedge as the down sheep have straggled about near the thorns. Buds have begun to take the shape of leaves. There is just a glimpse of new colour along the top of the distant wood; a momentary glint of sun gives the impression and no more of pale golden green, which dies as the sky leadens again. Underfoot the most notable thing is the growth of small clover. Stalks have lengthened and leaves broadened out well above the ground.
One of our rivers, which takes a very winding course down to the Thames, runs through a thicket of willows, with older trees pollarded along each bank. This evening, when the clouds dispersed, a pair of kingfishers chased under the yet bare branches, going at regular intervals and returning, not together but one after the other in the same way. There is more life in the water and more insects were playing below the still boughs. A warbler was singing – just a few notes, and then a long silence before he broke it again.
Continue reading...Hanging on rather than flourishing … a rare flower
New Forest Clustered around two trees, and shaded by them, is a narrow-leaved lungwort, unreported in the area for nearly 20 years
We head into the forest in search of a scarce plant. Nine years ago almost to the day, I chanced upon a single stem of narrow-leaved lungwort (Pulmonaria longifolia), and I want to find out if it is still there. Then, it had been growing in the shelter of a young bramble, with primroses alongside.
Before setting out, I check with Martin Rand, the botanical recorder for south Hampshire. When he tells me that he hasn’t had a report of its presence in this area since the turn of the millennium, I regret not having given him a note of my find before.
Continue reading...The nuclear boy scouts: radioactive obsessions and genius unleashed
Hunting the Ghost Fungus: glowing mushrooms in Australia’s forests
Standing in a dark pine forest surrounded by bioluminescent mushrooms is as magical and mysterious as it sounds – and worth the midnight trek into the mountains three hours out of Sydney
It’s just before midnight and we’re in the middle of an eerie pine forest in the Blue Mountains of New South Wales, dodging leeches and lugging heavy camera equipment.
Continue reading...Country Breakfast Features Saturday 15th April
New study shows worrisome signs for Greenland ice | John Abraham
Greenland ice is melting fast, and could potentially cause many meters of sea level rise
As humans put more heat-trapping gases into the atmosphere, like carbon dioxide, ice around the planet melts. This melting can be a problem, particularly if the melting ice starts its life on land. That’s because the melt water flows into the oceans, contributing to rising sea levels. Right now there are three main reasons that sea levels are rising. First, as ocean waters heat, they expand. Second, melting of ice in Antarctica flows into the ocean. Third, melting of ice on Greenland flows into the ocean. There is other melting, like mountain glaciers, but they are minor factors.
Okay, so how much is melting of Greenland contributing to sea level rise? Estimates are that about 270 gigatons of water per year are melting. The melting of an ice sheet like that atop Greenland can occur from the surface as air temperatures and sunlight warm the upper layer of ice. It can also occur from the edges as ice shelves collapse and fall into the oceans in large chunks.
Continue reading...What ingredients are needed for life beyond Earth?
Key ingredient for life found spewing from Saturn's icy moon Enceladus
Quarantine alert might have prevented white spot disease outbreak, review finds
Federal authorities investigating prawn imports did not tell Biosecurity Queensland about breaches
The white spot virus outbreak that devastated prawn farms in south-east Queensland may have been avoided if federal authorities investigating quarantine failures had warned the state’s biosecurity agency, a review has found.
The damning assessment is contained in the report of a marine biologist, Ben Diggles, who was contracted to investigate the white spot outbreak by the Fisheries Development and Research Centre – a body jointly funded by government and industry.