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DNA reveals separate populations of killer whales

Using two decades’ worth of DNA samples, Flinders University researchers have determined that at least three distinct populations of killer whales (orcas) occupy Australian and New Zealand waters – and they’re structured around matrilineal ties.

“We have found three populations of killer whales within Australasian waters – one in tropical, a second in temperate Western Australia, and a third in New Zealand,” says lead researcher Isabella Reeves, a PhD candidate at Flinders University.

“They each have distinct female-driven societies. These populations appear to have little movement between them, and a low number of breeders.”

While these apex predators have long been known to frequent our waters, seasonal aggregations have only recently been discovered, and little was known about their population structure.

“This research provides the first baseline for population structure of Australasian killer whales to be used for management, and highlights the need for increased research effort of these elusive animals,” says Luciana Moller from Flinders University, co-author of the paper published in Marine Mammal Science.

2D twist

How do you make more efficient solar cells? Just do the twist, according to researchers from the Australian National University.

In a study published in Cell Reports Physical Science, the team explored a new class of 2D materials that are essentially two atom-thin layers of different compositions stacked atop each other.

“This unique structure and large surface area make them efficient at transferring and converting energy,” explains lead author Mike Tebyetekerwa.

The double layering allows the materials to move positive and negative charges in opposite directions and thus generate electricity, giving rise to a range of applications, from solar cells to LED lights.

Tebyetekerwa and team showed that adjusting the angle between the two layers can dramatically change how they work, allowing them to more efficiently convert light into electricity.

It’s never too late to quit smoking

Quitting smoking could lengthen your life even if you already have lung cancer, according to a new study published in Annals of Internal Medicine.

Over seven years, the researchers followed 500 smokers who were diagnosed with early-stage non-small lung cancer. Participants who subsequently quit smoking (44.5% of the cohort) were more than 10% likely to be alive five years later than those who didn’t quit.

Those who quit smoking lived an average of 6.6 years after diagnosis, as opposed to 4.8. years for those who continued smoking.

Tuna troubles for Pacific Islands

Climate change is driving tuna east across the Pacific Ocean, away from the island nations that depend on these big fish for food and income, according to a new study in the journal Nature Sustainability.

The results – based on robust modelling – show that if ocean warming continues at the current rate, the tuna catch across the waters of 10 of the Pacific Small Island Developing States (SIDS) will decline by 20% by 2050.

“This is a climate justice issue,” says Johann Bell, lead author of the study from Conservation International’s Center for Oceans.

“The 10 Pacific SIDS have a deep economic dependence on tuna fishing but contribute little to global warming. In contrast, nations responsible for 60% of historical greenhouse gas emissions would benefit from the migration of tuna to the high seas.”

Gut bugs keep centenarians going

According to a new study in Nature, people over the age of 100 have friendly gut bugs that might help them live longer.

The study compared the gut microbiota of 160 centenarians, 112 elderly individuals (from 85 to 87 years of age) and 47 younger people (21 to 55 years).

The participants over 100 years of age were found to have a greater number of distinct types of gut microbes that can produce bile acids that inhibit the growth of other disease-causing bacteria. This could potentially contribute to longevity, according to the Japanese researchers.

However, the authors note that further research is needed to determine the link between bile acids and longevity.