Intertidal warming causes mortality and disrupts the microbiome of oysters

We simulated intertidal warming in the field by placing populations of Sydney rock oysters (Saccostrea glomerata) on black and white concrete tiles to create distinct thermal conditions. These tiles were positioned on the intertidal shoreline among natural oyster beds. During low tide, oysters on black tiles experienced temperatures up to 3 degrees Celsius higher than those on white tiles. We monitored oyster survival over six days and collected gill and haemolymph samples for microbiological analysis using qPCR, 16S rRNA, and HSP60 rRNA sequencing. After six days, oyster mortality on the black tiles was 50 percent higher than on the white tiles.