Figure-7.21: pH time series for the waters off Atlantic Canada

pH (depth-averaged) time series over the Scotian Shelf (1933–2014, declining trend of 0.026 per decade; 1995–2014, declining trend of 0.044 per decade); near-bottom estimate (approximately 300 m) of pH in the Gulf of St. Lawrence (1935–2007, declining trend of 0.021 per decade; 1990-2007, declining trend of 0.026 per decade); and pH from the central Labrador Sea in the annually ventilated layer (150–300 m) (1996–2016, declining trend of 0.029 per decade). Estimates of pH before the 1990s have a high level of uncertainty because of the quality of the measurements and should be interpreted with caution. Therefore, no assessment of statistical confidence is provided for the observed trends.


Data for the Scotian Shelf and Labrador Sea from the DFO monitoring database. Data for the Gulf of St. Lawrence derived from Mucci et al. (2011).