The creatures that will outlive us all
Poor sleep linked to Alzheimer’s
Sleeping badly could put people at greater risk of Alzheimer’s disease. So say researchers in the US, who have found a significant association between breathing disorders such as sleep apnea, and the accumulation of biomarkers for Alzheimer’s. And though a cause and effect link has not been proven, they think that treating these disorders might reduce people’s risk of the disease, or at least slow its progression. Obstructive sleep apnea is believed to affect around 30% of men and 20% of women, and occurs when the upper airway closes during sleep. In one study, the team looked at the accumulations of amyloid plaques – a marker for Alzehimer’s – in the brains of 500 people who did not have dementia, and found that people with sleep problems had more of this plaque than those who did not. In a second study, they looked at nearly 800 people with mild cognitive impairment – often a precursor to dementia – and found that levels of beta-amyloid were higher in those with sleep problems. “These findings indicate that sleep apnea may be facilitating cognitive decline,” said Megan Hogan, of Wheaton College, Illinois. “Screening for and [treating] sleep apnea should be a high priority, especially in individuals with mild cognitive impairment.”
Our modern, plastic world
Before the War, it barely existed. Since then, we have produced 8.3 billion tons of plastic – equivalent to the weight of 25,000 Empire State Buildings, according to a study published in the journal Scientific Advances. Some 70% of the plastic produced has been thrown away; of that, only 9% has been recycled, and 12% incinerated. Which means billions of tons of plastic is piling up in landfill sites, or in the natural environment. In Britain, it is estimated that we throw away 16 million plastic bottles every day.
The last survivors
When the nuclear war has been lost, and the asteroid has struck, when our oceans are dead, and even the cockroaches have given up the ghost, one creature will endure: the tardigrade. These tiny, eightlegged “extremophiles”, also known as water bears, are so resilient, scientists believe they will outlive every other species – and could even outlive our Sun. In fact, it’s hard to imagine a cataclysmic event that could eliminate them. Deprived of water, they dry into husks, but come back to life if rehydrated; put them in a freezer at -20°C, and they’ll go into a suspended animation in which they can survive for decades. They can endure temperatures as high as 150°C for a few minutes, and as low as -200°C for days. They’re at home in the low-pressure vacuum of space; they’re equally at ease in the crushing pressure of the Marianas Trench, in the Pacific. “It is hard to work out how to kill tardigrades,” said Dr David Sloan, an Oxford University astrophysicist. “Could you get the planet cold enough? No. Increase the pressure enough? No. Make the oceans acidic enough? No.” To eliminate them, he reckons you’d have to boil the oceans dry – “not a simple task”. The existence of such resilient creatures raises the chances of life existing on planets with conditions that would seem to preclude it. It also offers reassurance that long after the human race has been wiped out, life on Earth will continue.
Beavers restoring wetlands
Beavers reintroduced to rivers in Scotland are helping to restore the local landscape, turning fields drained for farming back into biodiverse wetlands. A team from Stirling University looked at the effects of a group of beavers on land near Blairgowrie, in Tayside, and found that over 12 years from 2003, the number of plant species grew by 148%; in the same period, the creatures built 195 metres of dams, 500 metres of canals, and an acre of ponds. “Wetland restoration normally involves raising water levels, for example by ditch blocking, plus mowing or grazing to maintain diversity,” said Dr Alan Law, an author of the study. “Beavers offer a more hands-off solution.” However, farmers continue to express strong concern that if their populations are not contained, the rodents are liable to cause enormous damage to productive farmland – by, for instance, destroying vital drainage systems.