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On Jupiter’s moon Europa, ‘chaos terrains’ could be shuttling oxygen to ocean

Jupiter’s moon Europa is a top contender when looking for alien life because scientists have detected signs of oxygen, water, and chemicals that could be used as nutrients there. However problematically the vast liquid water ocean on its surface is covered by a crust of ice – estimated to be about 15 to 25 kilometres thick – that acts as a barrier between it and oxygen on the surface.

For life as we know it to exist in the ocean it needs oxygen, and it could be hitching a ride on salt water under the ‘chaos terrains’ of the icy shell, according to a new study published in Geophysical Research Letters.

‘Chaos terrains’ are landscapes of cracks, ridges, and ice blocks that cover a quarter of Europa, and which scientists think form when the ice shell partially melts to form brine. This brine can then mix with the oxygen at the surface and drain through the ice into the ocean below.

Researchers built the world’s first physics-based computer simulation of the phenomenon and have shown that the brine drains in a distinctive manner, taking the form of a ‘porosity wave’ that causes pores in the ice to momentarily widen – allowing the brine to pass through – before sealing back up.

The researchers say that the highest estimates of the oxygen brought to Europa’s ocean could be on par with what’s present in Earth’s oceans today.

Europa's 'porosity wave' chart
The physics-based model built by the researchers shows brine and oxygen at Europa’s surface being carried by a “porosity wave” (spherical shape) through the moon’s ice shell to the liquid water ocean below. The chart shows time (in thousands of years) and ice shell depth (in kilometers). Red indicates higher levels of oxygen. Blue represents lower levels of oxygen. Credit: Hesse et al.

Birds are laying their eggs earlier due to climate change

Many bird species in Chicago are nesting and laying eggs nearly a month earlier than they did a hundred years ago, according to a new study, which looked at century-old eggs preserved in collections of the Field Museum.

By comparing the dates in which the preserved eggs hatched (collected from roughly 1880-1920) and recent observations (from about 1990 to 2015), scientists were able to determine a third of the 72 bird species nesting in Chicago have moved their egg-laying forward by an average of 25 days.

And as far as the researchers can tell, the culprit in this shift is climate change.

“The majority of the birds we looked at eat insects, and insects’ seasonal behavior is also affected by climate,” says lead author John Bates, curator of birds at the Field Museum, U.S. “The birds have to move their egg-laying dates to adapt.”

The research was published in the Journal of Animal Ecology.

Ann mclennan bigelow 1951 photo by john bayalis field museum z84894
Ann McLellan Bigelow working in the Field Museum’s egg collections in 1951. Credit: John Bayalis, Field Museum

Rescued Victorian period rainfall data smashes former records

When the citizen science Rainfall Rescue project was launched in March 2020, it offered members of the public a distraction from the COVID-19 pandemic by digitally transcribing 130 years’ worth of handwritten rainfall observations from across the UK and Ireland.

Since then, some 16,000 volunteers responded to the challenge with their efforts revealing record-breaking Victorian weather (the driest year on record is now 1855), as well as providing more context around recent changes in rainfall due to human-caused climate change.

The results have been published in a new study in Geoscience Data Journal.

Startling similarities between the ‘teeth’ of grasshoppers and mammals

It likely comes as a surprise that not all grasshoppers eat grass – in fact, some are even carnivorous. But studying grasshopper diets can be difficult, as it requires detailed study of the contents of their guts or painstaking and time-consuming observations of how they feed in the wild.

Now, new research lead by paleobiologists has used sophisticated three-dimensional imaging techniques to precisely map the shape of grasshopper’s mandibles (used for biting and chewing), and comparing them with the topography of mammal teeth.

“Surprisingly, comparing the mandible landscapes of grasshoppers with mammals’ teeth allows grasshopper diet to be predicted with 82% accuracy,” says lead author Chris Stockey, a PhD student at the University of Leicester, UK.

 “Pretty amazing when you consider that the mouthparts of mammals and grasshoppers have evolved independently for 400 million years, and were not present in their common ancestor.”

Their findings were presented in Methods in Ecology and Evolution.

Grasshopper mandibles scan
An illustration of grasshopper mandibles with different landscapes adapted to processing different diets captured by dental topographic metrics. The most complex undulating landscapes are associated with tough plant material such as grasses. Grasshoppers with steeper topographies and sharp cliff edges eat animals. Grasshoppers with other diets have different combinations of these characteristics. Credit: Chris Stockey/University of Leicester

Bacterial enzyme makes new type of biodegradable polymer

A bacterial enzyme crystal structure shown here makes a new type of biodegradable polymer acholetin which might someday find use in drug delivery tissue engineering or other appl
A bacterial enzyme (crystal structure shown here) makes a new type of biodegradable polymer, acholetin, which might someday find use in drug delivery, tissue engineering or other applications. Credit: Adapted from ACS Central Science 2022, DOI: 10.1021/acscentsci.1c01570

Strings of sugars, called polysaccharides, are the most abundant biopolymers on Earth. There is significant interest in their potential to replace synthetic polymers – such as plastics derived from fossil fuels – because they are biodegradable. These molecules also show promise as carrier materials for a broad range of therapeutics, because they’re not toxic to living tissue.

Now, researchers have identified a previously unknown bacterial enzyme that can make a new type of polysaccharide – which they’ve named acholetin – described in a new study published in ACS Central Science.

By screening a library of bacterial enzymes for their activities, the researchers found a candidate from a common contaminant of laboratory cell cultures: a bacteria called Acholeplasma laidlawii. They then expressed, purified, and determined the crystal structure of the enzyme, which they suspect could be involved in maintaining the bacteria’s cell membrane.

The new molecule, acholetin, could be useful for drug delivery, tissue engineering and other biomedical applications.

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