Modelling the effects of pH, temperature and flow on the growth and distribution of reef corals.
The distribution of coral reefs worldwide is determined by a number of environmental factors such as pH and temperature which affect the metabolic rates of photosynthesis, respiration and calcification. Increases in atmospheric carbon dioxide results in both increasing sea surface temperature and more carbon dioxide dissolving in seawater (increasing its acidity). Modelling is required to predict coral response to changes in pH and temperature. Are the responses the same at different life-stages? Are the responses the same for different coral species and morphology? How does flow affect the responses?
An aim of this study is to model the effect of decreasing pH and rising temperatures on coral responses. Another aim is to understand how these effects can be modified by fluctuating flow velocities and their affect on coral dynamics and reef accretion. The study corals are a branching species of Acropora and a digitate Porites which represent fast and slow growing life-histories. Flow velocity will be measured by tracking hydrated artemia cysts; calcification, after a period of acclimation, by the alkalinity anomaly technique; pH will be manipulated by varying the carbon dioxide concentration and temperature by mean of heat pumps.