Modelling the effects of ‘coastal’ acidification on copper speciation

• Main Authors: Richards, Russell, Chaloupka, Milani, Sanò, Marcello, Tomlinson, Rodger
• Format: Article in Journal/Newspaper
• Language: unknown
• Subjects: Moreton; Moreton Bay; Ocean acidification
• Online Access: http://www.sciencedirect.com/science/article/pii/S0304380011004352

We present here a copper speciation model that accounts for the long-term (‘coastal-acidification’) and short-term (daily and seasonal variation) variability in water pH and water temperature. The developed model is applied to a sub-tropical estuary (Moreton Bay, Australia) at a one hundred year time scale so that outputs are consistent with climate change projections. The model predicts that the mean cupric ion concentration (Cu2+) in the estuary will increase by 115% over the next 100 years as a result of the projected decrease in pH and increase in water temperature. Through calibration, the estimated concentration of copper-complexing dissolved organic matter (DOM) in the estuary is found to be 22.5nM. An increase in the concentration of Cu2+, which is the most toxic and bioavailable form of copper, has implications for ecosystem health and may have a negative effect on the detoxifying capacity of DOM. Models that provide a framework for coupling biological, chemical and physical processes are important for providing a holistic perspective of coastal systems, especially for better understanding a system within the context of climatic and non-climatic drivers. Ocean acidification; Copper speciation; Stochastic model; Coastal waters; Moreton Bay;