Ionic concentrations in a blanket peat bog in northern England and correlations with deposition and climate variables

Soil solution was collected to identify seasonal trends in its chemistry an d to examine relationships between the concentrations of ions and variables that may control them. Samples were collected fortnightly at 10 cm and 50 cm depth in a blanket peat soil at Moor House-Upper Teesdale National Natur e Reserve in the northern Pennine uplands of England. Dissolved organic car bon at 10 cm peaked each summer and correlated most strongly with temperatu re. At both depths Na+ and Cl- were the dominant ions, reflecting the ocean ic climate. Over the 3-year sampling period, concentrations of the principa l anions and cations at 10 cm varied little except during the autumns of 19 94 and 1995 following unusually dry summers. At these times concentrations of SO42--S increased from < 3 <mu>mol to a maximum of 430 mu mol and were b alanced by smaller increases in Na+, Mg2+, Ca2+ and H+. The SO42- concentra tion at 10 cm was most strongly correlated with depth to the water table 3 weeks prior to sampling. At 50 cm depth in the peat a small increase in SO4 2- occurred only during the autumn of 1995, and the concentration of SO42- at this depth correlated most strongly with that at 10 cm. At neither depth were there any strong correlations with deposition. The increase in H+ con centration associated with the peak in SO42- at 10 cm depth represents a fa ll in pH from usual values around 4.2 to 3.5.