title: Trends of natural organic matter concentrations in river waters of Latvia.
abstract: This study revealed significant (P < 0.1 and P < 0.05) increasing trends of total organic carbon (TOC) and water colour in most of the studied Latvian rivers during the last decade. However, over longer time periods, there were pronounced oscillations of TOC concentrations, similar to patterns of long-term changes of river discharge regime. On a yearly basis, there was a positive correlation between parameters of organic matter concentration and discharge in all selected rivers (r (S) = 0.540-0.803; P < 0.01). The impact of discharge on concentrations of organic matter could be masked by other factors, such as changes in precipitation, biological processes, soil types or land use.
authors.affiliation: Department of Environmental Science, University of Latvia, Raina blvd. 19, Riga 1586, Latvia. ilga.kokorite@lu.lv
authors.forename: Ilga
authors.initials: I
authors.lastname: Kokorite
authors.forename: Maris
authors.initials: M
authors.lastname: Klavins
authors.forename: Valery
authors.initials: V
authors.lastname: Rodinov
authors.forename: Gunta
authors.initials: G
authors.lastname: Springe
mesh_terms: D002244:Carbon / Q000032:analysis*; D004784:Environmental Monitoring; D007844:Latvia; D045483:Rivers / Q000737:chemistry*; D012987:Soil / Q000032:analysis*; D014874:Water Pollutants, Chemical / Q000032:analysis*; D014877:Water Pollution, Chemical / Q000706:statistics & numerical data*
chemical_list: D012987:Soil; D014874:Water Pollutants, Chemical; D002244:Carbon