An assessment of an environmental gradient using coral geochemical records, Whitsunday Islands, Great Barrier Reef, Australia

► First study to use coral proxy records to examine the Whitsunday Islands gradient. ► First study to show a regional GBR-scale change in the coral Ba/Ca ratio after 1860. ► Research provides new insights into the environmental influences on coral proxies. ► Research shows a change in the environmental gradient since European settlement.