Australia’s Great Barrier Reef has suffered another mass bleaching event – the third in just five years. Warmer sea temperatures – particularly in February – are feared to have caused huge coral loss across the world’s largest reef system.

Scientists say they have detected widespread bleaching, including extensive patches of severe damage. But they have also found healthy pockets. Two-thirds of the reef was damaged by similar events in 2016 and 2017. The reef system, which covers over 2,300km (1,400 miles), is a World Heritage site recognised for its “enormous scientific and intrinsic importance”.

Last year, Australia was forced to downgrade its five-year reef outlook from poor to very poor due to the impact of human-induced climate change. On Thursday, the Great Barrier Reef Marine Park Authority said its latest aerial surveys had shown that the severity of bleaching varied across the reef. But it said more areas had been damaged than in previous events.(BBC)…[+]

Mexican protesters have shut a US southern border crossing amid fears that untested American travellers will spread coronavirus. Residents in Sonora, south of the US state of Arizona, have promised to block traffic into Mexico for a second day after closing a checkpoint for hours on Wednesday.

They wore face masks and held signs telling Americans to “stay at home”. Mexico has fewer than 500 confirmed Covid-19 cases and the US over 65,000. The border is supposed to be closed to all except “essential” business, but protesters said there has been little enforcement and no testing by authorities. The blockade was led by members of the group Sonorans for Health and Life, who called for medical testing to be done on anyone who crosses from the US into Mexico.(BBC)…[+]

As US states ramp up restrictions to contain the coronavirus, Texas has joined Ohio in deeming nearly all abortions as non-essential procedures that must be delayed. The order against elective procedures is meant to keep valuable medical resources for those treating Covid-19 only.

In Texas, providers can be fined or jailed for violating the order. Abortion rights groups have criticised the move.

They say abortion should be considered an essential service. It comes as states across the country grapple with shortages of critical medical necessities, including masks, hospital space and ventilators. Medical professionals have pleaded for more supplies as many are falling ill or having to quarantine themselves after exposure.

Texas Attorney General Ken Paxton on Monday issued the clarification of Governor Greg Abbot’s earlier mandate on non-essential medical procedures. A statement from Mr Paxton’s office said “no one is exempt from the governor’s executive order on medically unnecessary surgeries and procedures, including abortion providers”, according to the Texas Tribune. It noted any providers in violation of the order – which expires 21 April – could be fined $1,000 (£853) or jailed for a maximum of 180 days.(BBC)…[+]

The transatlantic slave trade might seem like something from a distant and barbaric era – but a historian has found evidence its last survivor was alive in living memory. Hannah Durkin, at Newcastle University, had previously identified the last surviving slave captured in Africa in the 19th Century and brought to United States as a woman called Redoshi Smith, who died in 1937. But she has now discovered that another former slave, Matilda McCrear, had lived three years later. Matilda died in Selma, Alabama, in January 1940, at the age 83 – and her rebellious life story was the last living link with slaves abducted from Africa.(BBC)…[+]