Imma Perfetto
Cosmos science journalist
Tropical spider can hide underwater for 30 minutes
Jaws might have popularised the phrase “just when you thought it was safe to go back in the water…”, but in even more bad news for swimmers a new study has found a large tropical spider that can hide underwater for as long as 30 minutes to avoid getting squished by your shoe.
While some arachnids such as the diving bell spider live underwater, in general the class avoid submersion. Now biologists in Costa Rica seeking to capture the long-legged arachnid Trechalea extensa instead watched it sink into a water pool, using a “film” of air to remain submerged.
They reported their findings in the journal Ethology, noting that the fuzzy hairs that cover its body helped to maintain this film of air, helping to prevent heat loss and water from entering the spider’s respiratory organs while underwater.
Faster tsunami warning with speed-of-light gravity signals
Monitoring gravity changes that travel at the speed of light might hold the key to quicker tsunami warnings after large earthquakes, according to a new study in Nature.
Current warning systems based on seismic waves can be too slow to accurately assess the size of large earthquakes (magnitude 8 or above). Now, geoscientists have trained an AI model to assess ‘Prompt Elasto-Gravity Signals’ (PEGS), which are caused by the mass movement of rocks during earthquakes, estimating their size and location in real-time.
They trained the model using 350,000 modelling scenarios of earthquakes originating at 1,400 potential earthquake locations in Japan, and then tested this against real data from the 2011 quake.
Although the model is specific to Japan, the authors say that it could easily be adapted to other regions, with only small changes needed to implement the strategy in real time.
Fossil DNA shows effect of ancient climate change on eastern moa
The New Zealand extinct eastern moa has given scientists new insights into how species react to climate change, with a recent study finding that during the last Ice Age these large flightless birds changed their distribution as the climate heated and cooled.
Geneticists analysed ancient DNA from moa fossils and found that while the species had been spread across the eastern and southern South Island during the prior warmer Holocene period, their range reduced to just the south during the height of the last Ice Age (25,000 years ago).
“The eastern moa’s response had consequences for its population size and genetic diversity – the last Ice Age led to a pronounced genetic bottleneck which meant it ended up with lower genetic diversity than other moa living in the same areas,” says lead author Dr Alex Verry, a researcher in the Otago Paleogenetics Laboratory at the University of Otago, New Zealand.
The findings are reported in the journal Biology Letters.
Mercury removal made easy in toxic environments
Mercury pollution is a global problem. The result of mining, cement- and metal-production and other industries utilising fossil fuels, it’s found in neighbouring water, air and soil.
In many developing countries its removal can be too expensive or difficult, but a new sustainable extraction material – made entirely from low-cost waste from petroleum, citrus, and agricultural production – has been developed by Australian chemists.
They’ve shown that a free-flowing powder created by coating silica with sulphur and limonene can absorb more than 99% of waste mercury in water in just a few minutes. The research is published in a new study in Physical Chemistry Chemistry Physics (PCCP).
