Science roundup: How beehives can help save the environment

Indigenous people of the Canary Islands got around

Today the Canary Islands are a tourist hub, a volcanic archipelago with palm trees and azure beaches, located off the coast of Morocco and governed by Spain. But the history of this paradise is marred by the brutal conquest, enslavement and treatment of its indigenous people by European colonisers beginning around the 15th century.

Although scientists know a fair bit about the fate of the islands’ original inhabitants, much is unknown about their origins. Some scholars have debated whether the indigenous people sailed to the islands themselves more than 1,000 years ago or were stranded there by ancient Mediterranean mariners.

Increasingly, the evidence points to an intentional journey. Ancient DNA from skeletal remains found across the islands now suggests that the islands’ earliest pioneers were North Africans who may have arrived around AD 100 or earlier, and settled on every island by at least AD 1000. The finding supports previous archaeological, anthropological and genetic studies indicating that the island’s first inhabitants were Berbers from North Africa, a group that today lives in Morocco, Algeria, Tunisia, Libya and parts of the Sahara.

“This is the first ancient DNA study that includes archaeological remains from all the seven Canary Islands,” says Rosa Fregel, a population geneticist at the Universidad de La Laguna in Spain. Her team’s results, which were published recently in the journal Plos One, also undercut the idea that the islands’ early indigenous inhabitants were not explorers in their own right.

To investigate the early peopling of the Canary Islands before Europeans arrived and introduced the slave trade, Fregel and her colleagues collected nearly 50 mitochondrial genomes from remains at 25 sites. Mitochondrial DNA offers population geneticists clues to help decipher ancient human migrations. Most of the sites were radiocarbon dated between approximately AD 150 and 1400, although a couple of them came after post-conquest periods.

“In the Canary Islands indigenous people, we find typical North African lineages, but also some other lineages with a Mediterranean distribution, and also some lineages that are of sub-Saharan African origin,” Fregel says. That fits with the archaeological and genetic history of North Africa, she says: previous studies have shown that by the time the Canary Islands were inhabited, Berbers from North Africa had already mixed with Mediterranean and sub-Saharan African groups.

Giant snowman found in icy outpost 4 billion miles away

To Kirby Runyon, a planetary scientist at the Johns Hopkins Applied Physics Laboratory, the small distant object that Nasa’s New Horizons spacecraft flew past on the first day of this year reminds him of monkey bread.

For people not familiar with this sweet pastry, monkey bread consists of balls of dough that are piled into a pan. As they bake, the balls combine into a larger whole. It is a structure that may help explain the process that turned bits of dust and gas into planets in the early solar system.

New Horizons travelled some 4 billion miles to take a close-up look at this 22-mile-long world in the solar system’s icy Kuiper belt beyond Neptune; it is officially designated as 2014 MU69 and nicknamed Ultima Thule. Planetary scientists have never been able to take a close-up look at an object this distant, a small shard that has been frozen and almost unchanged since it formed 4.5 billion years ago.

Ultima Thule was not as picturesque as New Horizons’ first target – Pluto, in 2015 – but it was full of surprises. The shape turned out to be unlike anything seen in the solar system. It was not just a simple ball, but two objects that at some stage touched and stuck together, like a snowman. Then the scientists discovered that the two lobes of Ultima Thule were not spherical but more like lumpy pancakes. The larger lobe is also flatter than the smaller one.

The New Horizons team presented its newest findings recently at the Lunar and Planetary Science Conference in The Woodlands, Texas, a suburb of Houston.

Runyon of the mission’s science team described how lines on the surface of Ultima Thule appeared to delineate distinct clumps that might have once been smaller bodies.

“Just like Ultima Thule, they come together to form something wonderful,” Runyon says.

That is a change from older ideas of planetary formation: that objects called planetesimals grew slowly and steadily in size. Ultima Thule suggests an alternative scenario in which a bunch of similarly sized objects merged together over a shorter interval of time.

Just kick over the beehives to test air quality

Organic things can carry coded messages about their home environments. Tree rings can tell scientists what the atmosphere was like when the tree was young. Lichens can reveal local air pollution levels. Now, scientists in Canada report that honey carries a message, too.

A survey of urban beehives around Vancouver, British Columbia, which was published recently in Nature Sustainability, showed that the hives’ honey contained minute levels of lead, especially downtown and near the city’s port. The readings suggest that honey can be a sensitive indicator of air quality. And with urban hives growing in number and already more numerous than many people realise, tracking their pollutant levels may offer an inexpensive way to monitor what’s in the air all over the world, says Dominique Weis, a professor of geochemistry at the University of British Columbia and a co-author of the paper.

The project began when Hives for Humanity, a nonprofit that manages community beehives around the city, asked Weis to check the honey for lead and other substances. Bees are known to pick up trace amounts of metals, which settle on leaves and flowers from the air, as they forage for pollen.

The results showed very small levels of lead, along with traces of iron, zinc and other substances. A person would have to eat more than a pound of the honey a day to reach the US Food and Drug Administration’s provisional tolerable lead intake level for an adult, Weis says. The Hives for Humanity honey compares favourably with honey elsewhere; its lead levels are below the worldwide average.

More interesting to the scientists, however, was that the technique showed how honey could serve as a sensitive pollution detector. The chemistry of different samples can reveal where the honey came from. Volcanoes, river rocks, coal and other natural sources of lead have their own distinctive signatures, based on the ratio of different isotopes of the heavy metal in them, says Kate Smith, a graduate student who worked with Weis and led the study. It was clear that the ratio of lead isotopes in the honey the team studied did not match the ratios detected in the nearby Fraser River or local sediments.

Squid share a colourful trick with peacocks

Squid are the chameleons of the ocean, shifting effortlessly from hue to hue as they cross sand, coral and grass. Scientists have long studied the peculiar structures in their skin that interact with light, trying to understand how the animals change colour so swiftly and with such precision.

Now, a paper published recently in Nature Communications suggests that their chromatophores, previously thought to be mainly pockets of pigment embedded in their skin, are also equipped with tiny reflectors made of proteins. These reflectors aid the squid to produce such a wide array of colours, including iridescent greens and blues, within a second of passing in front of a new background. The research reveals that by using tricks found in other parts of the animal kingdom – like shimmering butterflies and peacocks — squid are able to combine multiple approaches to produce their vivid camouflage.

The researchers studied Doryteuthis pealeii, or the longfin squid, which is found in the North Atlantic Ocean and might turn up on your plate when you order calamari.

Its chromatophores contain individual sacs of yellow, red or brown pigment. Each one is also ringed with small muscles that allow the animal to clench shut or open wide each chromatophore. That means that in front of brown seagrass, for example, red and yellow chromatophores might cinch closed, allowing the brown pigments to show.

But what is the source of all those vivid blues and greens that squid are known to display? Researchers had long imagined that the layer below the chromatophores in the squid’s skin might be responsible for those pyrotechnic shimmers. That underlayer is essentially an enormous reflector, made of cells that make a protein called reflectin.

However, that layer responds to changes too slowly to be the sole source of those colours, says Leila Deravi, a professor of chemistry at Northeastern University and an author of the new paper.

Analysing the proteins that the chromatophore cells were making, researchers realised that reflectin was among them and they confirmed with further lab work that it was distributed around the surface of the chromatophores.

An aspirin a day might not keep the doctor away

For years, low-dose aspirin has been described as a panacea to ward off heart attacks, strokes and other cardiovascular diseases. New guidelines, though, suggest that aspirin should not be prescribed to most adults who are in good cardiovascular health and that the risk of internal bleeding often outweighs the benefit.

The American College of Cardiology and the American Heart Association released the new guidelines recently. They come on the heels of studies released last year that said daily low-dose aspirin – 100 milligrams or less – did not help older adults who do not have cardiovascular disease. Those results, published in three articles in The New England Journal of Medicine, surprised physicians and patients alike who for years believed aspirin would prevent any number of heart-related ills.

The authors of the new guidelines say low-dose aspirin should not be routinely given as a preventive measure to adults 70 years and older or to any adult who has an increased risk of bleeding.

“The guidelines are for people with no clinical signs of heart disease or stroke,” says one of the authors, Dr Erin Michos, associate director of preventive cardiology at Johns Hopkins School of Medicine.

She emphasised, though, that people who have had heart attacks or have stents should continue with the medication. “They should still take aspirin,” she adds.

Patients should consult their primary care doctor or cardiovascular physician before beginning or stopping the taking of aspirin.

Michos says she had been telling her patients who do not have cardiovascular disease to stop taking aspirin. “They are receptive to that,” she says.

Instead, the guidelines recommended several behavioural changes to ensure a healthy heart. These include maintaining a healthy weight, not smoking, engaging in moderate activity for at least 150 minutes a week and a diet that includes vegetables, fruits, nuts, whole grains and fish.

© New York Times

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