pH of the Lower Cape Fear Estuary Nate Cline CHM 576 November 30, 2009

pH Measure of acidity or basicity of a solution Commonly measured water parameter Impacts many chemical and biological processes pH = - log [H⁺] Normal scale ranges 0 – 14 < 7 is acidic > 7 is basic = 7 is neutral

Factors that Affect pH Salinity Increases with increasing salinity Depth σ saltwater > σ fresh water, therefore pH deep > pH surface Rainfall Rain is acidic, so pH decreases with increasing rainfall Photosynthetic Activity Increases with removal of CO 2 H 2 O + CO 2  (CH 2 O) n + O 2 Less carbonic acid available to dissociate

Conclusions pH and salinity are directly related pH increases as salinity increase pH and depth are directly related pH increases as depth increases pH could be affected by by rainfall Significant rainfall observed during Cruise 2 Noticeable pH differences between surface and deep during Cruise 2 Rainfall data needed before conclusions can be made