Scientists are examining how ‘blood rain’ affects soil microbiome, with Portuguese vineyards a particular focus Scientists are examining how ‘blood rain’ affects soil microbiome, with Portuguese vineyards a particular focus D ust events, when thousands of tonnes of fine sand whipped up from the Sahara are dumped over Europe , are becoming more intense. These sometimes produce “blood rain” that leaves visible red streaks, and while generally harmless, the dust is not sterile but brings a freight