Scientists have chronicled the “mass mortality” of corals on the Great Barrier Reef, in a new report that says 30% of the reef’s corals died in a catastrophic nine-month marine heatwave. The study, published in Nature and led by Prof Terry Hughes, the director of the ARC Centre of Excellence for Coral Reef Studies, examined the link between the level of heat exposure, subsequent coral bleaching and ultimately coral death. The extent and severity of the coral die-off recorded in the Great Barrier Reef surprised even the researchers. Hughes told Guardian Australia the 2016 marine heatwave had been far more harmful than historical bleaching events, where an estimated 5% to 10% of corals died.

“When corals bleach from a heatwave, they can either survive and regain their colour slowly as the temperature drops, or they can die,” Hughes said. “Averaged across the whole Great Barrier Reef, we lost 30% of the corals in the nine-month period between March and November 2016.” The scientists set out to map the impact of the 2016 marine heatwave on coral along the 2,300km length of the Great Barrier Reef. They established a close link between the coral die-off and areas where heat exposure was most extreme. The northern third of the reef was the most severely affected.(theguardian)…[+]

Senior figures from the global chemical weapons watchdog have flatly rejected Russian claims that the watchdog’s laboratories had found a western military chemical agent in the poison that incapacitated the Russian double agent Sergei Skripal.

In a weekend claim widely picked up on social media, the Russian foreign minister, Sergei Lavrov, said that a Swiss laboratory used by the Organisation for the Prohibition of Chemical Weapons had discovered traces in the sample of the nerve agent BZ and its precursors. The nerve agent is possessed by Nato countries, but not Russia. The Russian embassy in London said it was “highly likely” that BZ had therefore been used in Salisbury, adding that the OPCW and the British had questions to answer.

But at a meeting of the OPCW executive in The Hague, the Russian claim was refuted by OPCW officials, who said explained that BZ had been used in the control sample, not the sample itself. It is also a breach of OPCW procedures to identify a laboratory involved in a test. The UK said Russia had been caught out in an attempt to mislead the international community, adding the OPCW report showed the world was facing “a clear case of a new family of toxic chemicals intended to kill”.(theguardian)…[+]

A UN security team doing reconnaissance at the site of an attack in the Syrian town of Douma has come under gunfire, the head of the Organisation for the Prohibition of Chemical Weapons has said, further delaying the arrival of chemical weapons inspectors. The OPCW director general, Ahmet Üzümcü , told a meeting at the organisation’s headquarters in The Hague on Wednesday that the security team had been forced to withdraw. Üzümcü said that when a reconnaissance team arrived at one site, a large crowd gathered and the team withdrew. At a second site “the team came under small-arms fire and an explosive was detonated. The reconnaissance team returned to Damascus.” The delay in the inspectors’ arrival, 10 days after the attack, will raise fresh concerns over the relevance of the OPCW investigation and possible evidence-tampering.(theguardian)…[+]