Indigenous Australian fire-stick farming began at least 11,000 years ago

Indigenous Australians have been using fire to shape the country’s northern ecosystems for thousands of years. Researchers analysed charcoal that was preserved in the sediment of a flooded sinkhole over the last 150,000 years. They discovered that, around 11,000 years ago, there was a shift to more frequent but less intense fires as a result of Indigenous fire-stick farming. European colonisation mostly brought an end to the practice, which might have contributed to the return of more high-intensity wildfires.

1.75-billion-year-old fossils help explain how photosynthesis evolved

The oldest fossil evidence of photosynthesis has been found inside tiny cyanobacteria that lived around 1.75 billion years ago, 1.2 billion years earlier than the previous record-holder. The photosynthetic structures, known as thylakoids, were found inside fossilised Navifusa majensis. Cyanobacteria are thought to have triggered the Great Oxidation Event more than 2 billion years ago, which transformed Earth’s atmosphere.

Soil is home to more than half of all life

About 59% of all species on Earth live in soil, estimate researchers who reviewed global biodiversity data. This would make the ground the planet’s single most biodiverse habitat. The figure doubles an earlier estimate and could be even higher because so little is known about soil, the researchers suggest. It is home to 99% of Enchytraeidae worms, 90% of fungi, 86% of plants and more than 50% of bacteria — but only 3% of mammals live in it.

Sea life bounced back fast after the ‘mother of mass extinctions’

Marine life bounced back surprisingly quickly after the ‘mother of mass extinctions’ killed 81% of marine species 251.9 million years ago. More than 1,000 fossils uncovered in southern China show fish, ancient lobsters and prehistoric crab-like creatures existed just a million years after volcanic activity heated the atmosphere and acidified the oceans. It challenges the idea that complex ecosystems took millions of years to recover in a stepwise fashion, from self-sufficient organisms to apex predators.

‘Lunar wobble’ influences mangrove growth

Long-term fluctuations in the Moon’s orbit — known as the lunar wobble — could influence mangrove canopy growth. Researchers in Australia used high-resolution satellite images to measure mangrove canopy across the continent between 1987 and 2020. They found that the wobble, which pulls low tides lower and high tides higher in a cyclic pattern that lasts about 18 years, was a major factor in the expansion and contraction of mangrove growth. Depending on the phase of wobble, mangrove ecosystems get less water — resulting in thinner canopy cover — or higher tides that increase growth. Mangroves are natural carbon sinks, so the findings could help to better assess how much carbon they will store over time.