Read more
Geo News

Slow-motion earthquakes

While normal earthquakes release energy suddenly and catastrophically, the slow-motion variety can last from days to months, can’t be felt by humans, and cause no damage. Slow-slip earthquakes were discovered around 20 years ago, and scientists are still trying to figure out what causes them. New Zealand’s Hikurangi Subduction Zone, off the east coast of the North Island, has become a global hotspot for the study of slow-slip quakes, because they happen at shallower depths than they do elsewhere, and so are easier to measure. The Hikurangi Subduction Zone is where the Pacific Plate is being shoved underneath the North Island, which lies on the edge of the Australian Plate. Off the coast of Wellington and the Wairarapa, the seabed is covered in sediment washed off the Southern Alps. That gives the Pacific Plate a nice, smooth surface, and as it’s pushed underneath the Australian Plate, the two plates tend to lock tightly together. (Every 500 years or so, this breaks in a giant megathrust earthquake of magnitude 8 or 9.) North of Hawke’s Bay, it’s a different story. There’s less sediment, so ancient undersea volcanoes called seamounts stick up out of the Pacific Plate, giving it a bumpy surface. That causes all kinds of strange behaviour as it’s sucked beneath the Australian Plate. GNS Science geophysicist Susan Ellis and her colleagues used a sophisticated computer model to simulate what happens when a seamount is pulled into the subduction zone. “The ground ahead becomes brittle and prone to earthquakes because the water is squeezed out,” says Ellis. As the seamount inches forward, it drags the seabed with it, stretching apart the rocks behind it and allowing fluids to fill tiny gaps in the rock. That weakens the rocks and makes slow-slip earthquakes possible. Researchers are trying to figure out what this means for New Zealand. How much of the stress built up along the fault will be released in slow-slip events? What will happen when the southern part of the Hikurangi Thrust eventually ruptures in “the big one”—something that hasn’t happened in recorded history?
Read more
Geo News

Bird flu barrier

A particularly virulent strain of avian influenza called H5N1 has spread to more than 60 countries since it was identified in 1996. The virus’s fatality rate in humans ranges from 50 to 60 per cent, but it hasn’t figured out how to leap between human and human: it can only make the jump between birds and people. An international consortium of scientists studied how the virus spreads, and found that its travel is associated with China’s live poultry trade. The same was true of two other strains of bird flu. “While the H5N1, H7N9 and H5N6 avian influenza viruses have not yet learned to transmit human-to-human,” says New Zealand virologist Robert Webster, “they do have pandemic potential.”  
Read more
Geo News

The private lives of cats

Where do cats go—and how lethal are they? Researchers put trackers on 925 pet cats in Australia, New Zealand, the United Kingdom and the United States, through four citizen science projects, in order to figure out how large the cats’ home range was, and how often they killed. They found that the average domestic tabby had a similar ecological impact as a wild predator, but over a small range; the cats killed on average 3.5 animals per month within 100 metres of their home. Only three cats in the study roamed more widely than a square kilometre—one New Zealand cat roamed over farms, while a British cat walked almost two kilometres between villages. Older cats, male cats, and urban cats moved less. The researchers recommended pet owners find ways to entertain their cats indoors in order to reduce their environmental impact. Meanwhile, a small study on the role of pets in the health of older adults had an unanticipated finding; Australian researchers interviewing 35 people aged 60 to 83 were surprised to learn that pets had protected some from suicide. Twelve of the study’s participants spoke about how their pets gave them a reason to live. Caring for an animal gave them a sense of purpose, its physical presence warded off loneliness, and, most importantly, they felt “known” by their pets.
Read more
Geo News

Lake destruction

Storms upend lake ecosystems, causing confusion in their microscopic communities, according to a new study involving NIWA scientists. The study looked at the existing research on phytoplankton, the base of the food web and a determinant of water quality, but found little information on how storms affect it. “If extreme weather events significantly change carbon, nutrient, or energy cycling in lakes, we better figure it out quickly,” says Jason Stockwell, an aquatic ecologist at the University of Vermont who led the new research, “because lakes can flip, like a lightbulb, from one healthy state to an unhealthy one—and it can be hard or impossible to flip them back again.”  
Read more
Geo News

Our slimy relatives

Palaeontologists have discovered our earliest ancestor—a tiny, bug-like creature that burrowed in the mud half a billion years ago. It is the first known bilatarian—an animal that’s largely symmetrical and has a front and a back, with a mouth at one end and an anus at the other. This body type turned out to be a successful innovation. It’s the shape sported by most animals today. “We now have evidence of the origin of groups of animals which went on to conquer the Earth,” says James Gehling from the Australian Museum, co-author of a paper describing the new species. It was named Ikaria wariootia. Until now, palaeontologists traced our ancestry to the explosion of marine lifeforms in the Cambrian period, which began 541 million years ago. It was thought that fossils from the earlier Ediacaran period represented some of evolution’s failed experiments—dead ends on the family tree. But this discovery, made in South Australia’s Flinders Ranges, shows that our lineage dates all the way back to the Ediacaran. The Ediacaran was “a very weird world”, says Gehling. “Little bugs like the Ikaria were ploughing through thin layers of sand, eating microbial mats. The world was really one of slime. We have nothing equivalent to it today. You’ve got to think as though you’re on a different planet.” The name acknowledges the Adnyamathanha, the indigenous custodians of the land on which the fossils were found. Ikaria is a nod to Ikara, the Adnyamathanha word for meeting place, while the species name comes from nearby Warioota Creek. There’s still so much we don’t know about these ancient animals and their strange home, says Gehling. “But whatever they were, life expands after that point and changes the planet—and that interaction between life and environment is something that indigenous people have always thought about. What we’re doing here is acknowledging that we scientists aren’t the first people that needed to understand origins.”
Read more
Geo News

Light conversation

Out in the deep ocean, where it’s darker than a moonless night all day long, packs of two-metre-long Humboldt squid go hunting. They spend their short lives on fast-forward—always on the move, always hungry, even turning on their own kind if an individual shows a moment’s weakness. They’re also highly social, and a new study suggests they use a complex visual language to communicate in the deep. Studying the behaviour of deep-sea creatures like the Humboldt squid isn’t easy, says author Benjamin Burford from the Monterey Bay Aquarium Research Institute. “They’re born in the open ocean, they die in the open ocean—they never touch a hard surface in their life. They don’t know what a wall is. So when you bring them into captivity, they will ram themselves to death in a tank. It’s way better to meet them where they live.” To do that, Burford and co-author Bruce Robison sent high-definition video cameras 800 metres deep in the Pacific Ocean’s California Current, and analysed the flickering and flashing displays Humboldt squid were using. They identified a repertoire of 28 pigmentation patterns—such as “mottled”, “dark fins”, or “pale circles around the eyes”. The squids used particular combinations of these signals while feeding: they’d go half-dark, half-light when approaching prey, add a dark spot between the eyes, then flash pale all over when pouncing. When it’s so dark, how can they make out the signals? Humboldt squid have bioluminescent photophores scattered over their body. Unusually, they’re not in the skin, but buried beneath in their muscles. Burford mapped the location of these cells and found the areas with the highest densities corresponded to the parts of the body used in some of the most important signals. That suggests the squid use their bioluminescent bodies to make their changing skin patterns easier to see. “They’re basically concealing and revealing different parts of a glowing body,” says Burford. So, what are they saying? “When Humboldt squid feed, it looks like a feeding frenzy. But if you pay close attention, they’re not bumping into each other, they’re not attacking each other, they’re rarely even in competition for the same prey item. We think the pigmentation patterns they’re producing are helping them organise this chaos, so it doesn’t end in catastrophe—in a misunderstanding that leads to fighting and injury or death.” Burford likens it to using indicators, brake lights and horns when stuck in traffic. The squid are saying things like, “I’m going for that fish over there, and stay out of my way, because I’m dominant around here.” But it’s also more complicated than that. It looks as though the squids combine signals to make new meanings—a kind of syntax. “Is it language? It’s definitely a way of communicating, which is what we use language for.” It should be possible to create a squid hologram, project different visual behaviours on it, and test how wild Humboldts react to it, says Burford. “Maybe some day we’ll learn how to speak squid.”
Read more
Geo News

Rising from the ashes

In the wake of Australia’s catastrophic bushfire season, the country’s forests face yet another pressure: logging. While it may seem reasonable to salvage timber from ravaged eucalypts, evidence suggests otherwise. Semi-burned trees and scorched logs are crucial to ecosystem recovery, offering shelter and food to surviving wildlife. “Many trees that look dead will still be alive. In the months ahead, buds will sprout from under the blackened bark,” says David Lindenmayer, a professor at the Australian National University. Already, a peppering of rain across the Blue Mountains has seen tiny buds of new growth appear after bushfires razed millions of hectares across the UNESCO World Heritage Area and multiple national parks. Following the deadly Black Saturday fires in 2009, post-fire logging in Victorian forests destroyed emerging seedlings and removed tree hollows, which are important for endangered species such as the Leadbeater’s possum and red-tailed black cockatoo. A 2016 study found that tree fern numbers plummet by 94 per cent after post-fire logging, while another study found that soils fail to regain their nutrients and fungal communities even 80 years after fire and logging. Fire risk also increases in areas that have been logged after fires. “At a time when habitat is so scarce,” says Lindenmayer, “practices like burning or mulching remaining timber, salvage logging and mop-up burning rob landscapes of the features that wildlife will need to recover.”
Read more
Geo News

Dive-in movie

How does a cephalopod see the world? If you’re a cuttlefish in this experiment, you see it through a pair of 3D glasses, and your world is lit by videos of shrimp. This was the unlikely experimental set-up of a research project in the United States that investigated just how the cuttlefish (Sepia officinalis) is able to snatch prey with its tentacles while its eyes swivel independently. The cuttlefish’s relatives, octopuses and squid, don’t have 3D vision, but researchers suspected that cuttlefish do. Humans see in three dimensions thanks to a process called stereopsis, or depth perception: each eye, when looking at the same scene, perceives each object being in a slightly different position. Our brain triangulates, allowing us to accurately measure the objects’ distance from us. But what happens when your eyes look in different directions at the same time? This is where the 3D-spectacled cuttlefish come in. Participants were dubbed Supersandy, Sylvester Stallone, Long Arms and Inky, and introduced to their underwater movie theatres. Like 3D cinema technology, two identical images of shrimp were projected so that each cuttlefish eye would perceive them in a slightly different position. Some of the shrimp would appear to be in front of the screen and others behind it. If the cuttlefish were using stereopsis, their eyes would combine the two images to give 3D information, and they would strike with their tentacles accordingly. This is exactly what happened. When the cuttlefish ‘saw’ a shrimp projected up close, they reversed and shot their tentacles out in front of them. Then, when the shrimp appeared to be further away, the cuttlefish swam right into the wall of the tank in pursuit of it. The cuttlefish were seeing with stereopsis, but they weren’t using the same neural circuitry to process the images as humans. For instance, they didn’t have perception problems when one of the two images was brighter than the other, as humans would, or when one eye looked in a different direction. This suggests that what the cuttlefish visualise is different from what humans perceive. Another recent study that delved into the complex brains of cephalopods mapped the mind of the bigfin reef squid (Sepioteuthis lessoniana) with MRI, creating an atlas of its neural connections. The researchers, from the Queensland Brain Institute at the University of Queensland, identified new connections among the squid’s 500 million neurons, the majority of which were connected to vision or movement. Their brains, say the researchers, approach those of dogs in their complexity: squid can count, solve problems, recognise patterns, and camouflage themselves, despite being colour-blind.
Read more
Geo News

Aotearoa’s ark

As some humans ponder their own extinction, others are figuring out the best places to run when the bomb drops, or the power goes off, or the supermarkets shut their doors. In a study published in the journal Risk Analysis, researchers Matt Boyd and Nick Wilson rated the appeal of the world’s islands as sanctuaries from a catastrophe such as a global pandemic. “The results indicate that the most suitable island nations for refuge status are Australia, followed closely by New Zealand, and then Iceland, with other nations all well behind,” they concluded. In particular, they considered subnational islands, such as Australia’s Tasmania, Japan’s Hokkaido, and New Zealand’s South Island. “Nevertheless, some key contextual factors remain relatively unexplored,” they cautioned, such as the willingness of those islands to accept refugees. And would we have enough cheese rolls for everyone?
Read more
Geo News

New dogs, old tricks

Tens of thousands of years ago, grey wolves and humans teamed up, and as time passed the wolves’ bodies shrank, their temperaments became friendlier, their ears flopped and they learned to interpret human commands. Over the course of millennia, dogs were shaped by human need and whim, resulting in a motley line-up that runs from tireless herder to teacup pup. And humans have been training dogs for so long that some human instructions appear to be embedded in dogs’ brains. A recent study, published in Frontiers in Psychology in January, detailed an experiment which took place across several cities in India. Researchers offered two covered bowls to stray dogs and pointed at one of the bowls. About half of the dogs did not approach the bowls, which the researchers attributed to anxiety from previous unpleasant encounters with humans. But, of the dogs that did advance towards the bowls, about 80 per cent followed the pointing finger, indicating that the dogs had an innate understanding of human body language. In another study, researchers from Stockholm University in Sweden conducted a series of behavioural experiments with eight-week-old wolf pups. In one, a person who was a stranger to the pups threw a ball for the 13 youngsters. The researchers didn’t expect much to happen, but three wolf pups did something surprising: they fetched. They even brought the ball back to the stranger with minimal encouragement. Human-directed behaviour in canines was thought to have resulted from domestication, but the surprise game of fetch suggests this behaviour may have preceded—and even aided—the taming process. Wolves that fetched would have been more valuable to early humans than pups that displayed no aptitude for retrieving.
Read more
Geo News

Surface of the sun

Like bubbles in a pot of boiling water, this solar close-up shows convection cells on the sun’s surface. Hot plasma (bright white) rises from the sun’s interior, then cools and sinks (dark outlines). Each convection cell is around 2.5 times the size of New Zealand. It was photographed from a new solar observatory, the Daniel K. Inouye Solar Telescope (DKIST), which looks sunward from the summit of Haleakalā (literally ‘the house of the sun’), a 3000-metre peak in Hawai’i. The facility has a four-metre-wide mirror to resolve our nearest star in intimate detail. Features as small as 30 kilometres across can now be photographed. Looking directly at a burning ball of gas is tricky. Sunlight focused by the telescope generates enough heat to melt metal so, to keep the telescope cool, the facility makes a swimming pool’s worth of ice every night, then distributes it via more than 10 kilometres of piping. Why are we looking so closely at our star? Although the sun is nearly 150 million kilometres away, its weather can cause chaos on Earth. Solar flares and storms emit streams of charged particles that interfere with satellites and power supplies. By zooming in, astronomers hope to understand the magnetic processes behind such phenomena.
Read more
Geo News

Mesozoic beetles

It started with an insect preserved in amber. A round, shiny beetle a couple of millimetres long was found in Myanmar, encased in its golden tomb. It lived about 100 million years ago, in the mid-Cretaceous period, in a forest ecosystem on Gondwanaland. Upon close examination of the fossil, scientists from China classified it as part of the Cyclaxyridae family, a group of beetles with just two living relatives, both found in New Zealand. They inhabit the sooty mould ecosystem peculiar to New Zealand’s beech forests. In this community of organisms, scale insects live within the bark of beech trees, eating their sap and excreting glittering beads of honeydew. Bats and birds such as tūī and kākā feed on the honeydew, while excess dew fuels the growth of dense black fungus. This ‘sooty mould’ is eaten by beetles, including the two living cyclaxyrid species, Cyclaxyra jelineki and Cyclaxyra politula. Upon the Burmese amber discovery, scientists, including Richard Leschen from Manaaki Whenua–Landcare Research, re-evaluated another beetle fossil from Baltic amber, placing it in the cyclaxyrid family too. This trio of cyclaxrids suggests that sooty mould beetles (and the associated ecosystem) were once widespread across the supercontinent Pangaea. Now, they survive only on the semi-submerged Zealandia as relics. The search is on for more sooty mould beetle fossils—including here in New Zealand.
Read more
Geo News

No more blame

As social researchers seek ways to defuse hostility towards “outgroups”, one United States study has found a simple means to get people to rethink their attitudes towards, in this case, Muslims. First, the researchers asked their Spanish study subjects whether they considered themselves responsible for the actions of white supremacists such as Anders Breivik. Overwhelmingly, they felt that they were not. Then the researchers asked whether individual Muslims should be held responsible for the 2015 Paris terrorist attacks, which were committed by Islamic extremists. The subjects again said no. People’s natural desire to be consistent, say the authors, moderates prejudice and delivers more considered views on conflict.
Read more
Geo News

Singing the same tune

Picture the moa. A flightless feathered giant, reminiscent of an emu or cassowary. Over the last decade, genetic and skeletal evidence has begun to trace its family tree back to the age of the dinosaurs. Some 80 million years ago, the first ratites—the ancestors of today’s kiwi, emu and cassowaries—emerged. But the closest cousins of the moa were not kiwi, nor the cassowaries next door, but appeared to be an odd family of quail-sized birds an ocean away. The ground-dwelling tinamou is found across Central and South America, and can fly (although it prefers not to). With such a relationship, you would expect these birds to have some morphological similarities. But these have eluded scientists—until now. It was a serendipitous discovery. A research group at Flinders University in Australia were investigating the enigmatic cassowary, a rainforest-dwelling titan from northern Queensland. The team, including New Zealander Trevor Worthy, used cutting-edge scanning technology to 3D-image the cassowary’s throat structures—those involved in breathing, eating and vocalising. “Scanning lets us see details that we wouldn’t be able to otherwise, including the shapes of internal structures, without causing damage to them,” says the lead author on the paper, PhD candidate Phoebe McInerney. As part of the investigation, the team also imaged the throats of other birds in the palaeognath (“old jaws”) family, an ancient lineage separate to all other living birds. They found that tinamou and moa had comparable throat anatomy—a morphological similarity that can’t be seen in skeletons. The tinamou and moa were singing the same tune after all. The discovery further disproves “Moa’s Ark”—the idea that moa have inhabited Zealandia since the time of Gondwanaland. Instead, it’s possible that the moas’ ancestor flew to Zealandia from America (perhaps via Antarctica) after the southern continents drifted apart.
Read more
Geo News

Citizen skywatchers

When an undulating curve lit up the night sky above a group of Finnish aurora hunters, they flipped through their guidebook to identify it—but the aurora didn’t look like any of the 30 distinct forms pictured within. So the northern lights enthusiasts turned their cameras skyward, capturing the strange shape, which they called “the dunes”. “They told me I had excluded one aurora form from the book,” says Minna Palmroth, a space physicist at the University of Helsinki and author of the guide. Most aurora appear as shimmering green or pink curtains, stretched vertically. But the dunes were horizontal, like fingers of light reaching hundreds of kilometres towards the equator. Researchers from the University of Helsinki, including Palmroth, joined forces with the citizen skywatchers to document the new form, and their findings were reported in AGU Advances in January. Using the aurora hunters’ photos, scientists calculated the altitude of the dunes to be 100 kilometres above sea level. This suggests that the dunes are a visible manifestation of atmospheric waves—specifically, mesospheric bores, a type of wave that behaves like a ripple on the surface of a pond. “For the first time, we can actually observe atmospheric waves through the aurora. This is something that hasn’t been done before,” says Palmroth. Studying the dunes may help scientists understand the dynamics and interactions of Earth’s atmosphere in more detail. The new discovery echoes that of strong thermal emission velocity enhancement, or STEVE, a purple-green sky-glow phenomenon first documented by aurora seekers in Canada in 2016. Subsequent observations have confirmed that STEVE occurs in New Zealand skies—while photos captured by aurora seekers down under suggest that the dunes may also be part of the southern lights spectacle.
Read more
Geo News

Defying gravity

Cancer cell clusters are blasting off into outer space, in a research effort that aims to crack one of the final frontiers in cancer biology. Housed in a specially designed biomodule, samples of aggressive ovarian, breast, nose and lung cancer will travel to the International Space Station (ISS). The question at stake: how will the cells behave in microgravity? A malignant tumour consists of cancer cells stuck together that replicate uncontrollably, until a point is reached where the cells begin to break off and invade other parts of the body. This switch between clumping together and spreading isn’t well understood, but researchers reckon the cancer cells have a way to ‘sense’ each other, and that this sense relies on the presence of gravity to function. In a preliminary test in a zero-gravity chamber at the University of Technology Sydney, 80 to 90 per cent of cancer cells were ‘disabled’. Now, the mission to send cancer cells to the ISS aims to replicate this finding—with the hope it could lead to future therapies that trick cancer cells into thinking they’re in outer space. “It would not be a magic bullet, but it could give current treatments like chemotherapy a big enough boost to kill the disease,” said Joshua Chou, the scientist leading the study.
Read more
Geo News

Strolling to an early grave

New Zealand and United States researchers have found a link between slow walking speed at 45 years old and accelerated ageing. Their research, which used data from the long-running Dunedin Multidisciplinary Health and Development Study, also pegged slow walking to declining brain function, and indicators of reduced brain health in early childhood. The authors recommend that a walking-speed test be introduced in regular doctors’ check-ups, since gait proves to be an inexpensive indicator of general health.

Loading..

3 FREE ARTICLES LEFT

Subscribe for $1  | 

3 FREE ARTICLES LEFT THIS MONTH

Keep reading for just $1

Unlimited access to every NZGeo story ever written and hundreds of hours of natural history documentaries on all your devices.

$1 trial for two weeks, thereafter $8.50 every two months, cancel any time

Already a subscriber?

Signed in as . Sign out

Please log in

This page requires an NZGeo.com account. Please create one below, or sign in if you already have one.

* We’ll never pass your email address to third parties, or send you spammy stuff, we promise.

Thanks, you're good to go!

Thanks, you're good to go!

LET'S DO THIS

SEE THE OPTIONS

{{ contentNotIncluded('company') }} has not subscribed to {{ contentNotIncluded('contentType') }}.

Ask your librarian to subscribe to this service next year. Alternatively, use a home network and buy a digital subscription—just $1/week...

Go back

×

Subscribe to our free newsletter for news and prizes