A 90-day long experiment was conducted to understand the link between turbid nutrient-enriched conditions and elevated temperature condition, and their effects on corals. The objective of the experiment was to determine whether corals exposed to coastal water containing terrestrial runoff and sediment resuspension (nutrient enriched waters) increase protection against or increased sensitivity to the effects of thermal stress. Conditions in the experiment simulated realistic levels of elevated nutrients, sediments and heat stress found on coastal waters.

Colonies of two common scleractinian corals (Acropora millepora and Montipora tuberculosa) were collected from inshore reefs of the central Great Barrier Reef. Colony fragments were sourced from 2 - 4 meters depth. Acropora Millepora were sourced from Pelorus Island and Double Cone Islands, and Monitpora tuberculosa were sourced from Magnetic Island.

Samples were kept in coastal seawater, or organically and nutrient enriched coastal seawater (OE), and/or enriched with nitrate. Samples were acclimatised for 10 days, before temperature conditions gradually increased from 27°C to 31.2°C. After 3–7 weeks of heat stress, recovery after ending heat stress was also observed up to 31-38 days. Effects on both species were determined and quantified as differences in survival, photophysiological stress and recovery, and skeletal growth rates.

This study was jointly funded by the Australian Institute of Marine Science, the Australian Government’s Marine and Tropical Sciences Research Facility, and the Australian Government’s National Environmental Research Program.