Did our ancestors really chase animals until they collapsed from fatigue?
Just after midnight on November 14, 2016, more than 24 fault lines around Kaikōura ruptured in spectacular fashion. One of these rifts—the previously unmapped Papatea Fault—threw up a few extra surprises for scientists. Normally, the rupture of a fault is caused by a build-up of stress. But Papatea was stress-free until its rupturing neighbours squeezed it, triggering a violent fracture. In a matter of seconds, the earth split open along 19 kilometres and sections of mountainous land were shifted upwards by eight metres. Of the 24 fault lines, Papatea produced the largest vertical movement. At first, Papatea’s behaviour confused scientists, because the fault wasn’t under strain. In a study published in Science Advances in October, New Zealand and Canadian researchers used before-and-after images of the fault line to create a model and figure out what happened. It’s another unusual aspect of the most complex earthquake ever studied, with implications for assessing seismic risk. Current earthquake forecasting is based on the strain model, where faults accumulate tension until they fail, but Papatea shows that displacement is also a risk, says Mark Stirling, chair of earthquake science at the University of Otago: “A ten-metre displacement in a built-up area or beneath a critical facility, such as a large dam, would have significant consequences.”
Painting cows with black and white stripes reduces fly bites by 50 per cent, according to a study by a team of scientists in Japan, published in PLOS One in October. The zebra-print cows displayed fewer signs of annoyance, such as tail flicking and head shaking, and attracted lower numbers of biting flies than unpainted cows. The study was inspired by previous research suggesting the zebra’s iconic striped coat functions as a fly deterrent. The stripes are thought to work by confusing the insects: the pattern interferes with flies’ motion detection, and they fail to land on the striped surface. (This is, however, just one of a number of theories attempting to explain the evolutionary advantage of the zebra’s stripes.) Biting flies are a significant pest for cattle worldwide, including in New Zealand. Their persistent attacks cause stress and prevent cattle from sleeping and eating—which in turn affects growth and milk production.
Artificial intelligence can spot diseases with about the same accuracy as human professionals, according to a systematic review and meta-analysis published in The Lancet Digital Health in September. Across 14 studies, ‘deep learning’ algorithms correctly detected conditions ranging from cancers to eye diseases in 87 per cent of cases, compared to 86 per cent by doctors. Artificial intelligence was also marginally better at identifying patients who had a clean bill of health.
Genetic reanalysis in the Amazon has revealed that the electric eel is, in fact, three different species, including one—Electrophorus voltai—that can deliver an 860-volt shock. (That won’t kill a healthy person, says ichthyologist and lead author Carlos David de Santana, from the Smithsonian National Museum of Natural History.) The new species is now officially the strongest bioelectricity generator known, making the previous record of 650 volts a mild tingle.
Embryonic turtles can choose what they’ll be when they grow up: male or female. In particular turtle species, the temperature of the egg appears to determine the sex of the hatchling. Research published in August in Current Biology found that embryos are able to move around within the egg to find different temperatures. Wei-Guo Du and colleagues at the Chinese Academy of Sciences incubated turtle eggs at a range of temperatures, finding that an embryo could experience a gradient of up to 4.7°C within its egg. (A temperature change larger than 2°C can alter the sex ratio of many turtle species.) In half the eggs, researchers applied a chemical that blocked the embryos’ temperature sensors. When the eggs hatched, the embryos that weren’t able to sense temperature were either almost all males or almost all females. But the temperature-sensing embryos developed about half and half males and females. “The most exciting thing is that a tiny embryo can influence its own sex by moving within the egg,” says Du. This indicates that turtles may have the ability to shield themselves against extreme thermal conditions. Du warns that this may not be enough to protect them from rapid climate change, which is predicted to create female-biased populations. “However, the discovery of this surprising level of control in such a tiny organism suggests that in at least some cases, evolution has conferred an ability to deal with such challenges.”
A sea sponge may one day save millions of lives, according to a study published in Scientific Reports in October. Tuberculosis kills 1.8 million people each year, more than any other disease, and current vaccines are struggling to contain it. That’s because Mycobacterium tuberculosis, the organism that causes TB in humans, is quick to mutate, meaning it can soon evolve drug resistance. The quest for a better vaccine has led scientists beneath the waves, looking for bioactive molecules in sponges: compounds that might one day comprise the basis of new vaccines. Over three years, the Centenary Institute and the University of Sydney analysed around 1500 sponges, and discovered that a species of Tedania, a genus found around Australia and New Zealand, possesses potent powers against M. tuberculosis. The active component, Bengamide B, was able to halt drug-resistant TB strains, and did not harm human cells. “Bengamide B shows significant potential as a new class of compound for the treatment of tuberculosis,” said the study’s lead author, Diana Quan, “and also importantly, for the treatment of drug-resistant TB.”
Our next-door neighbour is a cannibal. Andromeda, the closest spiral galaxy to the Milky Way, has a history of eating smaller galaxies, and we’re next on the menu—in about four billion years. Research published in Nature in October documents the leftovers of galactic meals: dense star clusters called globular clusters dotted throughout the stellar halo orbiting Andromeda. By tracing the faint remains of smaller galaxies embedded in the globular clusters on Andromeda’s outskirts, researchers reconstructed how and when the smaller star systems were gobbled up. “We are cosmic archaeologists, except we are digging through the fossils of long-dead galaxies rather than human history,” said the study’s co-author, Geraint Lewis from the University of Sydney. Andromeda is on a collision course with the Milky Way—so now we have a clearer picture of the ultimate fate of our galaxy.
Normally, more than 200 sightings of great white sharks are recorded every year in False Bay, near Cape Town, South Africa. This year, that number is zero. Receivers that are supposed to ‘ping’ when a tagged shark passes by remain silent, while whale carcasses usually found in the bay are free of shark bite marks. False Bay is a renowned great white hotspot, and shark scientists are puzzled by the predators’ absence. It’s possible that orcas are the culprits—they’re known to attack great whites, and have a particular taste for their livers. Indeed, sightings of great whites decreased after two orcas visited False Bay in 2015. Alleged victims of orca predation have washed up along the South African coast, their livers removed with surgical precision—the orca’s calling card. This is also consistent with observations from Australia and California, where orcas on the prowl have led to a mass exodus of great whites. But there’s another suspect in this case: humans. It’s possible that changing prey distribution, pollution or overfishing could also be responsible for the missing sharks.
Warming seas will make life much harder for pāua, a NIWA study has found. Scientists raised young pāua in seawater of various temperatures and pH levels, then monitored their growth. “Essentially, seawater of the future will be warmer, with lower pH levels,” said Vonda Cummings, pictured, who led the study. “We found that the outer layer of pāua shells gets etched by seawater with lower pH, especially if the water was warmer.” The pāua were sensitive to temperature variations as small as 2ºC, “and that will affect the thickness of pāua shells, which could mean they are not as resistant to waves and predators”.
Residents and emergency services could better handle earthquakes if they knew whether the worst was over, or if it were still to come. Large earthquakes are often followed by aftershocks that are difficult to predict, and can sometimes be bigger than the first. Now, Swiss researchers have devised a system to help determine whether a magnitude 6.0 or greater earthquake is the main event, or merely a precursor. Laura Gulia and Stefan Wiemer of the Swiss university ETH Zurich analysed the sequences of earthquakes in the Amatrice–Norcia region in Italy and the Kumamoto region in Japan in 2016, devising a model for predicting the threat of a larger earthquake to follow. Tested against 58 known earthquake sequences, the model identified foreshocks and aftershocks with 95 per cent accuracy.
Scientists are finally able to confirm that quantum theory holds up even in the absence of gravity. Physicists fired quantum-entangled photons from the ground to the quantum satellite Micius, where they were remeasured. Getting quantum theory and Einstein’s Theory of General Relativity to agree has long been the holy grail of physics. Quantum mechanics is the province of atomic physics, while Einstein’s theory is concerned largely with gravity. “But a key barrier to progress on this problem,” said University of Queensland physicist Timothy Ralph, “has been the difficulty in performing experiments in which effects from both theories play a significant role simultaneously.” The team wanted to know whether quantum mechanical theories had to be rewritten to accommodate certain features of general relativity. “However, our results showed that gravity doesn’t affect quantum states in the speculated way,” said Ralph. “The bizarre predictions of quantum mechanics continue to be accurate, even under the extreme situation of transferring quantum particles many hundreds of kilometres from the Earth’s surface. “Perhaps it’s the theory of relativity that needs to evolve to reflect the scientific theories behind quantum mechanics, and not the other way around.”
Plotting sea-level fluctuations around Zealandia three million years ago has sounded a warning for the future. Using new techniques to analyse the size of particles pushed around by wave action during the Pliocene, researchers led by Georgia Grant of GNS Science have found that, at a time when carbon-dioxide concentrations were similar to today’s, and temperatures around 2ºC warmer, a third of Antarctica’s ice sheets melted, causing sea levels to rise up to 25 metres higher than at present. The scientists warn that we might expect sea-level rise of up to 20 metres should warming hit a 2ºC tipping point.
Can humans also regenerate damaged limbs?
Carlos Lehnebach has been looking for a ghost orchid for ten years. In July, he found one.
“Cats tamed humans about 4000 years ago, and since then they have cunningly used humans to provide food, comfort and safety, and to aid their dispersal across, and conquest of, most of the world,” write professors John Woinarski, Sarah Legge and Chris Dickman, who lead a major Australian study on the impact of cats on Australian wildlife. Cats are thought to have played a leading role in two-thirds of Australia’s mammal extinctions—that’s 20 species—over the last 200 years. Feral cats are greater killers than pet cats, because pets’ territory is limited by the number of other cats nearby. Cats also pose a threat on the microscopic level: a study by researchers at the University of Adelaide found that feral cats are effective at spreading the parasite Toxoplasma gondii. Kangaroos are particularly susceptible to it. In New Zealand, the parasite has been implicated in the deaths of endangered Hector’s and Māui dolphins, but the role it plays is not yet clear.
First, you’ll need some ancient seabed that has been buried in the Earth’s crust, cooked up deep down, and then spat out onto the surface. Macquarie University geoscientists studied how diamonds are formed. In experiments recreating the extreme pressures and temperatures found 200 kilometres underground, they demonstrated that seawater in sediment from the bottom of the ocean reacted in the right way to produce the balance of salts found in a diamond. Most diamonds found nearer the Earth’s surface are made this way. “There was a theory that the salts trapped inside diamonds came from marine seawater, but couldn’t be tested,” says lead author Michael Förster. “Our research showed that they came from marine sediment.”
Albatrosses are good omens for sailors, but are not having too much luck themselves. The population of female wandering albatrosses that nests on Antipodes Island has plummeted by two-thirds in the past 14 years. This rapid decline has alarmed researchers Kath Walker and Graeme Elliott, who have been studying the species for two decades. There appear to be a number of causes, but the primary one is changing oceanic conditions that force the birds to forage in more northerly waters where the risk of being caught by commercial longliners is higher. Some years have seen female mortality rates as high as 20 per cent. “We think about polar bears with despair, but it’s a rather similar sort of situation here,” said Walker in an interview with RNZ. [caption id="attachment_344954" align="alignnone" width="1066"] Numbers of Antipodean albatrosses are declining on the Antipodes.[/caption] Antipodean albatrosses forage for squid, which is also used as bait by the longliners. While many fishers have a suite of techniques and technology to avoid bycatch, those that don’t risk birds taking the hooks and drowning with the sinking line. As Antipodean albatrosses raise only one chick, and both adults provide food during the first year, the loss of a single adult often means the death of its chick too. Antipodean albatrosses range widely—far beyond New Zealand’s exclusive economic zone, into the stateless realm of the high seas and as far east as Chile’s continental shelf. Regional fisheries management organisations regulate fishers out there in a similar way to those in New Zealand waters, but the level of compliance and reporting of bycatch is debatable. Without better data on where the birds are foraging—and dying—researchers are at a loss to determine the threats to the population. There are some 3000 registered longliners in the Pacific, and it’s uncertain which vessels or jurisdictions they interact with. To complicate matters, female Antipodean albatrosses forage further to the north, in more dangerous waters, and are disappearing at a greater rate than the males, leading to a severely skewed sex ratio. The Department of Conservation and the Ministry of Primary Industries deployed about 75 satellite-transmitting devices on Antipodean albatrosses this year, and in association with the Southern Seabirds Solutions Trust, intend to deploy the same number again next season. The tags track the birds’ locations as they forage, and researchers can overlay this data with the position of fishing vessels operating in the area to determine the risk of contact. If left unchecked, the Antipodes Island wandering albatross could be the first albatross species in the world to become functionally extinct.
The largest animals in the ocean weren’t always mammals. They were birds. A newly discovered penguin was the size of a human—1.6 metres tall, weighing 80 kilograms. Its bones were unearthed from the Waipara Greensands in North Canterbury in 2011 by Leigh Love, an amateur palaeontologist. One of the fossils, encased in rock, sat in a display cabinet in Love’s living room for years. “I would use it for the fossil talks I did with school groups coming in,” says Love. “This thing would get passed around the kids: ‘Here’s something that’s about 60 million years old’.” In 2018, Love started to learn fossil preparation—the art of removing the rock to leave the bone exposed. He practised on a crab, then had a go at the penguin leg. It was soon clear it was a new species, dating from a time when penguins ruled the waves. “Marine mammals took 30 million years to evolve, so there was an ‘age of the giant penguins’ in the oceans for 30 million years before finally the whales and seals took over,” says Paul Scofield of Canterbury Museum. “There was a possibility that penguins were going to become whale-size—all the genes for true giganticism are in a bird, because they are dinosaurs. But it never happened, because mammals took over that niche.”
Manta rays have unique patterns of spots on their bellies, allowing individuals to be identified. University of Queensland researchers have created a database of more than 1300 manta rays, supported by a citizen-science project. Scientists are able to keep track of the movements and health of reef manta rays (Mobula alfredi) via photographs and videos submitted by members of the public. More than 7000 sightings have been recorded, showing that manta rays can travel up to 1000 kilometres at a time. The data will inform conservation projects and reef management.
Loading..
Thanks, you're good to go!
Thanks, you're good to go!
Ask your librarian to subscribe to this service next year. Alternatively, use a home network and buy a digital subscription—just $1/week...
Subscribe to our free newsletter for news and prizes
3
Unlimited access to every NZGeo story ever written and hundreds of hours of natural history documentaries on all your devices.
Already a subscriber? Sign in
