Effects of summer drought on peat soil solution chemistry in an acid gully mire S. Hughes1, B. Reynolds1, J. A. Hudson2, and C. Freeman3 1Institute of Terrestrial Ecology, Bangor Research Unit, Orton Building, UWB, Deiniol Road, Bangor, Gwynedd, LL57 2UP, Wales, UK. 2Institute of Hydrology, Staylittle, Llanbrynmair, Powys, SY19 7DB, Wales, UK. 3School of Biological Sciences, Memorial Building, UWB, Deiniol Road, Bangor, Gwynedd, LL57 2UP, Wales, UK.
Abstract. In a field experiment to investigate potential impacts of
climatic change, a small area of flush wetland in Wales was subjected to three successive years of simulated
summer drought/rewetting (autumn-spring) cycles (1992–94). Drought was simulated achieved by
diverting stream water around the experimental wetland during the summer, so that the
received only precipitation inputs during that time. The effects on peat-water chemistry
in the rhizosphere were monitored at regular intervals until spring 1996, and comparisons made
with a control. Simulated summer drought decreased, significantly, the natural summer
peaks in dissolved organic carbon (DOC) and iron, whilst subsequently increasing the natural
autumn-winter peaks in sulphate concentrations and acidity in the peat water. The effects
of simulated drought on SO4 concentrations in the peat water compared favourably with
events monitored following a natural summer drought in 1995. Autumn-winter peaks in
SO4 concentrations in the control wetland following the natural drought were of similar magnitude
to those induced by the drought simulated in the experimental wetland in the previous three
Citation: Hughes, S., Reynolds, B., Hudson, J. A., and Freeman, C.: Effects of summer drought on peat soil solution chemistry in an acid gully mire, Hydrol. Earth Syst. Sci., 1, 661-669, doi:10.5194/hess-1-661-1997, 1997.