What the scientists are saying…
An alternative to plastic bottles
It’s well known that our addiction to bottled water has environmental consequences: more than 200 billion plastic bottles are used worldwide every year. It takes a lot of water and oil to manufacture them, and only a fraction are recycled. Now the race is on to find a more sustainable alternative – and a team at Imperial College London is working on just such a thing: a flexible, edible sphere made from seaweed, known as the Ooho. You can poke a hole in it, and suck out the water, or pop the whole blob in your mouth in one go. Oohos are already being handed out at festivals; but there are some obstacles its creators must overcome if they are to make serious inroads into the bottled water market. Making Oohos involves dipping frozen liquid into a mixture of sodium alginate (extracted from seaweed) and the firming agent calcium chloride, to create a membrane. When the ice melts you end up with water in a biodegradable blob. But these are quite small, each providing only a gulp of water; and also quite fragile and wet to the touch, so they’re not suitable for carrying around in a bag or pocket; unless, of course, they are protected by an outer layer of packaging, which rather defeats the object.
Using bacteria to clear landmines
It is estimated that more than 100 million landmines are buried worldwide, and that they kill or maim up to 20,000 people a year. But to clear them, you first have to find them: some demining teams use dogs; in Mozambique and Tanzania, giant rats have been trained to sniff out explosive chemicals such as TNT. But many teams rely on variants on a metal detector, invented by a Polish army officer in 1941, which is effective but inefficient: it typically gives 1,000 false positives for every mine, making the process slow, and expensive. Now, researchers in Israel think there may be a quicker, cheaper method, using bacteria that have been genetically modified to glow in the presence of TNT vapour. The idea – first proposed in 1998, but only recently developed – is that the bacteria, embedded in polymeric beads, are spread over the minefield; then a laser, perhaps carried by a drone, is beamed onto the field, to illuminate any fluorescence, while the scene is filmed by a camera attached to the drone. In a small test, the team, from the Hebrew University of Jerusalem, buried 11 real mines, and one dud, in various mixtures of sand and soil. They then scanned the plot from 20 metres away. They picked up all the mines, except for the fake and four that had been in mud for five days. Refinements are needed, such as more sensitive beads, but it suggests the “biosensor” system has promise.
Life could exist on Saturn’s moon
A small icy moon that orbits Saturn could harbour life – albeit of a rather basic form. Late last year, the soon-to-retire Nasa probe Cassini was directed to fly through a plume of gas and grains sent up from cracks in the surface of Enceladus. Now, the samples have been analysed, and found to contain hydrogen gas. This suggests the presence of hydrothermal vents in subsurface oceans, which could be home to “extremophiles”, single-cell organisms adapted to conditions that would kill other forms of life. “The discovery of hydrogen gas and the evidence for ongoing hydrothermal activity offer a tantalising suggestion that habitable conditions could exist beneath the moon’s icy crust,” says Nasa’s Dr Hunter Waite. Were life to exist on Enceladus, it would offer insights into how life formed on Earth, and increase the odds of life being found elsewhere, too. It may be a fluke that life got started on Earth, but if it were found in two places in our solar system, “we could be pretty confident” that it also got started in other galaxies, Professor David Rothery, of The Open University, told The Independent. The Cassini probe is due to end its 20-year space mission in September, when it will plunge into Saturn’s crushing atmosphere.
Medical file
Hay fever sufferers are having a tough year, reports The Daily Telegraph. The birch pollen season (from catkins) started early this year, probably because of the mild winter and relatively early spring, and is liable to last another few weeks – by which time, the grass pollen season will have begun. “It has been particularly bad for people so far this year, and it’s likely to continue into the immediate future,” said Dr Jean Emberlin, of Allergy UK.