Furthermore, these late-spawning species and/or colonies may be at greater risk from the combined effects of high SST and pollution from flood plumes. To quantify this risk, both field studies and laboratory approaches are needed to understand the combined effects of climate change and pollution. A recent field study indicated that wastewater discharge has increased the susceptibility of coral communities in the Florida Keys to thermal bleaching. Similarly, the occurrence of coral bleaching on the GBR can be more accurately predicted when dissolved inorganic nitrogen concentration is included in the modelling framework. Such models indicate that reducing DIN by 50% –80% would help to protect inshore corals of the GBR by increasing the bleaching threshold by 2uC. Successful coral recruitment is important for the maintenance and recovery of coral communities under pressure from climate change and other anthropogenic influences. The profound effect that Cu has on exacerbating the negative effects of thermal stress on coral larval metamorphosis in the laboratory illustrates that water quality can be a particularly pressing issue for the health of coral reefs as SSTs increase due to climate change. The larval metamorphosis model developed here from experimental data demonstrates that reducing water contamination can have positive effects on coral recruitment. At a seawater temperature of 28uC, 50% of Acropora millepora and A. tenuis larvae successfully metamorphosed when Cu concentrations were approximately equal to 25 and 30 mg L21 respectively. However, halving Cu concentrations from these values resulted in more than 3.5uC increase in the temperature threshold for both species. Indeed, for each of the percentage metamorphosis thresholds depicted in Fig. 3, halving Cu concentrations from the value corresponding to the control temperature led to an increase in the temperature tolerance by 3–5uC. This study therefore provides empirical evidence to support government programs that aim to improve water quality to mitigate the negative effects of increasing seawater temperatures due to global change.