title: Long-term changes in acidity and DOC in throughfall and soil water in Finnish forests.
abstract: The main objective of this study was to examine if any detectable trends in dissolved organic carbon (DOC), sulphate (SO4-S) concentrations and acid neutralizing capacity (ANC) in throughfall (TF) and soil water (SW) could be found during 1990-2010 and to relate them to recent changes in decreased acid deposition. The study was conducted in seven boreal coniferous forest sites: four of which are managed and three unmanaged forests sites. Generally, temporal trend showed a significant decrease in SO4-S concentrations in bulk precipitation (BP), TF and SW. At some of the sites, there was an increasing tendency in BP and TF in the DOC concentrations. This feature coincides with decreasing SO4-S concentration, indicating that SO4-S may be an important driver of DOC release from the canopy. However, a slightly increased temperature, larger senescing needle mass and consequently increased decaying activity in the canopy may partly explain the increasing trend in DOC. In SW, no consistent DOC trend was seen. At some sites, the decreased base cation concentrations mostly account for the decrease in the ANC values in SW and TF.
authors.affiliation: Finnish Forest Research Institute, P.O. Box 18, 01301, Vantaa, Finland, liisa.ukonmaanaho@metla.fi.
authors.forename: Liisa
authors.initials: L
authors.lastname: Ukonmaanaho
authors.forename: Mike
authors.initials: M
authors.lastname: Starr
authors.forename: Antti-Jussi
authors.initials: AJ
authors.lastname: Lindroos
authors.forename: Tiina M
authors.initials: TM
authors.lastname: Nieminen
mesh_terms: D002244:Carbon / Q000032:analysis*; D002980:Climate; D004784:Environmental Monitoring; D005387:Finland; D065928:Forests; D005618:Fresh Water / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D012987:Soil / Q000737:chemistry*; D012989:Soil Pollutants / Q000032:analysis*; D013431:Sulfates / Q000032:analysis
chemical_list: D012987:Soil; D012989:Soil Pollutants; D013431:Sulfates; D002244:Carbon
references.citation: Sci Total Environ. 2002 Oct 7;297(1-3):21-41
references.pmid: 12389777
references.citation: Nature. 2007 Nov 22;450(7169):537-40
references.pmid: 18033294
references.citation: Science. 1983 Aug 5;221(4610):520-5
references.pmid: 17830936
references.citation: Sci Total Environ. 2006 Aug 31;367(2-3):811-21
references.pmid: 16600338
references.citation: Sci Total Environ. 2009 Dec 15;408(1):92-101
references.pmid: 19819522
references.citation: Environ Monit Assess. 2007 Feb;125(1-3):123-36
references.pmid: 17131083
references.citation: Environ Sci Technol. 2007 Nov 15;41(22):7706-13
references.pmid: 18075078
references.citation: Environ Sci Technol. 2006 Mar 15;40(6):1776-83
references.pmid: 16570597
references.citation: Environ Pollut. 2002;117(2):215-24
references.pmid: 11916036
references.citation: Environ Pollut. 2005 Sep;137(1):165-76
references.pmid: 15944047
references.citation: Nature. 2001 Aug 23;412(6849):785
references.pmid: 11518954
references.citation: Sci Total Environ. 2006 Jul 15;365(1-3):47-65
references.pmid: 16597460
references.citation: Environ Pollut. 2005 Sep;137(1):55-71
references.pmid: 15944040
references.citation: Environ Monit Assess. 2001 Jan;66(2):129-46
references.pmid: 11214347