Ocean acidification can cause the mass extinction of marine life, fossil evidence from 66m years ago has revealed. A key impact of today’s climate crisis is that seas are again getting more acidic, as they absorb carbon emissions from the burning of coal, oil and gas. Scientists said the latest research is a warning that humanity is risking potential “ecological collapse” in the oceans, which produce half the oxygen we breathe.

The researchers analysed small seashells in sediment laid down shortly after a giant meteorite hit the Earth, wiping out the dinosaurs and three-quarters of marine species. Chemical analysis of the shells showed a sharp drop in the pH of the ocean in the century to the millennium after the strike.

This spike demonstrated it was the meteorite impact that made the ocean more acidic, effectively dissolving the chalky shells of many species. Large-scale volcanic activity was also considered a possible culprit, but this occurred over a much longer period. The oceans acidified because the meteorite impact vaporised rocks containing sulphates and carbonates, causing sulphuric acid and carbonic acid to rain down. The mass die-off of plants on land after the strike also increased CO₂ in the atmosphere.

“We show ocean acidification can precipitate ecological collapse,” said Michael Henehan at the GFZ German research centre for geosciences in Potsdam, who led the study. “Before we had the idea, but we did not have the empirical proof.” The researchers found that the pH dropped by 0.25 pH units in the 100-1,000 years after the strike. It is possible that there was an even bigger drop in pH in the decade or two after the strike and the scientists are examining other sediments in even finer detail.(The Guardian)…[+]

Deep sea explorers have found two Japanese aircraft carriers that were sunk in battle in World War Two. The carriers were among seven ships that went down in the Battle of Midway, a major air and sea battle fought between the US and Japan in 1942.

One ship, the Kaga, was discovered last week, while wreckage from another carrier, Akagi, was found on Sunday. Until now only one other ship sunk in this battle had ever been found – the American vessel USS Yorktown, in 1998. This month’s discoveries came after weeks of searching by crew members based on the research vessel Petrel. The vessel is owned by Vulcan Inc, a company created by the late Microsoft co-founder Paul Allen.

The Petrel also worked with the US Navy, as according to US law it is otherwise illegal to disturb underwater war graves – that is, sites where the wrecks of US military ships lie. Both ships were found lying about 18,000 feet (5,490 metres) under water within the Papahanaumokuakea Marine National Monument – the largest marine conservation area in the world.(BBC)…[+]

The Duke of Cambridge is “worried” about his brother after he talked about his mental health in a TV documentary, a Kensington Palace source has told the BBC.

Prince William is said to be hoping the Duke and Duchess of Sussex “are all right” after they told an ITV documentary they were struggling. The palace source said there was a view the couple were “in a fragile place”. Kensington Palace had no comment on the ITV film, which aired on Sunday. The documentary followed the Duke and Duchess of Sussex on their tour of southern Africa earlier this month.

In interviews, the couple both said they were struggling with the intense scrutiny from elements of the British tabloid press.  The palace source played down suggestions that Prince William was “furious” with his brother after the documentary aired on Sunday. It followed Prince Harry’s admission in the film that he and William have “good days” and “bad days”. Asked about media reports of a rift between the brothers, the Duke of Sussex said that “inevitably, stuff happens” as a result of “this family being under the pressure that it’s under”.(BBC)…[+]