Combined effects of climate change and the herbicide diuron on the coral Acropora millepora

• DOI: 10.1016/j.marpolbul.2021.112582
• Publication Date: 2021-06-10T04:51:34Z
• Authors: Florita Flores; Joseane A. Marques; Sven Uthicke; Rebecca Fisher; Frances Patel; Sarit Kaserzon; Andrew P. Negri
• Keywords: 0106 biological sciences; Coral Reefs; Herbicides; 13. Climate action; Climate Change; Diuron; Animals; 14. Life underwater; Anthozoa; 01 natural sciences

The Great Barrier Reef (GBR) is threatened by climate change and local pressures, including contaminants in nearshore habitats. This study investigated the combined effects of a GBR-relevant contaminant, the herbicide diuron, under current and two future climate scenarios on the coral Acropora millepora. All physiological responses tested (effective quantum yield (ΔF/Fm'), photosynthesis, calcification rate) were negatively affected with increasing concentrations of diuron. Interactive effects between diuron and climate were observed for all responses; however, climate had no significant effect on ΔF/Fm' or calcification rates. Photosynthesis was negatively affected as the climate scenarios were adjusted from ambient (28.1 °C, pCO2 = 397 ppm) to RCP8.5 2050 (29.1 °C, pCO2 = 680 ppm) and 2100 (30.2 °C, pCO2 = 858 ppm) with EC50 values declining from 19.4 to 10.6 and 2.6 μg L-1 diuron in turn. These results highlight the likelihood that water quality guideline values may need to be adjusted as the climate changes.