Summary:
Published in Biogeochemistry 111: 393-409 https://doi.org/10.1007/s10533-011-9664-1
Within the southeast Canada and northeast USA region, a peak in sulphate (SO42-) concentration has been reported for some streams following periods of substantial catchment drying during the summer months (ON, Canada; VT, NH and NY, USA). However, it is currently unclear if a SO42- response to seasonal drying is widespread across the broader region, or to what extent the level of response varies among catchments. In our study, SO42- response to seasonal drying was compared in 20 catchments from 11 locations across southeastern Canada (ON, QC and NS) and northeastern USA (NH, NY, VT, WV and ME). Using long-term monitoring data of stream discharge and chemistry, the number of days for each month of the dry season (# d) when discharge (Q) was below a threshold level (25th percentile; Q25) was calculated for each catchment to give a measure of ‘seasonal dryness’ (# d Q < Q25). A SO42- response score (rs) was then calculated for each catchment based on linear regression analysis of # d Q < Q25 versus either the annual SO42- concentration, or the residual of annual SO42- concentration as a function of time (year). The final rs values for each catchment provided an estimate of the proportion of variation in annual SO42- concentration which could be explained by seasonal drying (possible rs range = 0–1). Of the 20 catchments, 13 exhibited some level of a SO42- response to seasonal drying (rs = 0.04–0.72) with an additional two catchments exhibiting a SO42- response for one or more seasons. SO42- response scores were positively related to percent wetland area(w) (rs = 1.000 - 0.978e-0.054*w, r2 = 0.44) and percent saturated area (sat) (rs = 0.481 - 0.488e-0.101*sat, r2 = 0.54) indicating that wetlands/saturated areas were an important driver of regional variation in the SO42- response to seasonal drying. Our results suggest that any shift towards drier summers as a result of climate change could impact SO42- dynamics in a large number of catchments throughout the region.
Sector(s):
Forests
Catégorie(s):
Scientific Article
Theme(s):
Ecosystems and Environment, Forest Ecology, Forestry Research, Forests
Departmental author(s):
Author(s):
KERR, J.G., M.C. EIMERS, I.F. CREED, M.B. ADAMS, F. BEALL, D.BURNS, J.L. CAMPBELL, S.F. CHRISTOPHER, T.A. CLAIR, F. COURCHESNE, L. DUCHESNE, I. FERNANDEZ, D. HOULE, D.S. JEFFRIES, G.E. LIKENS, M.J. MITCHELL, J. SHANLEY and H. YAO
Year of publication:
2012
Format:
Paper
How to get the publication:
Keyword(s):
sécheresse, nutrition, sulphate, bassin versant, biogéochimie, écologie forestière, écosystèmes et environnement, article scientifique de recherche forestière, ecosystems and environment, forest ecology, drought, nutrition, sulphate, watershed, biogeochemistry