Aquatic Sciences

, Volume 78, Issue 3, pp 505–523 | Cite as

Long-term trends (1975–2014) in the concentrations and export of carbon from Finnish rivers to the Baltic Sea: organic and inorganic components compared

  • Antti RäikeEmail author
  • Pirkko Kortelainen
  • Tuija Mattsson
  • David N. Thomas
Research Article


Finnish rivers exported annually on average 1.2 M t carbon, and total organic carbon (TOC) comprised the major share (nearly 80 %) of this export. The mean area specific carbon export was 4.5 g C m−2 year−1. The highest organic carbon export originated from peat dominated catchments, whereas rivers draining agricultural catchments had the highest area-specific inorganic carbon fluxes. Between 1975 and 2014 total inorganic carbon (TIC) concentrations rose more steadily than the respective TOC concentrations. There was an overall decrease in TOC concentrations between 1975 and the mid-1990s. Decreased point source loading contributed to this pattern, although decreases were also detected in rivers without any major pollution sources. From the mid-1990s TOC concentrations started to rise and the increase was even more pronounced than the earlier decrease. The upward trend was ubiquitous, both in time and space, and it was not possible to link the changes to any specific catchment characteristics or another single driver. Warming climate, changes in hydrology and decreases in acidic deposition were the major driving factors although their contribution varied geographically. At the same time both TOC and TIC export increased slightly, but the strong upward trends in TOC concentrations were not reflected as clearly in TOC export trends. This was because changes in water flow had a dominant influence on TOC export to the sea and any changes in concentrations were masked behind the variation in flow.


Organic carbon Inorganic carbon Concentration Riverine export Long-term trends Baltic Sea 



We thank the Academy of Finland (projects: “Biogeochemistry of the Baltic Sea in a Changing Climate: From Catchment to Open Sea (FiDiPro)” and “Fluxes of Terminal Electron Acceptors: Linking Human Disturbance to the Health of Aquatic Systems (TEAQUILA)” (decision no. 263476)) and NordForsk funded Domqua (Drinking water treatment adaptation to increasing levels of DOM and changing DOM quality under climate change) project for supporting this work. We are grateful to Chris Evans and two anonymous reviewers for their valuable comments on an earlier versions of the manuscript.


  1. Ågren A, Buffam I, Jansson M, Laudon H (2007) Importance of seasonality and small streams for the landscape regulation of dissolved organic carbon export. J Geophys Res 112:G03003CrossRefGoogle Scholar
  2. Algesten G, Sobek S, Bergstrom AK, Agren A, Tranvik LJ, Jansson M (2004) Role of lakes for organic carbon cycling in the boreal zone. Glob Chang Biol 10:141–147CrossRefGoogle Scholar
  3. Alling V, Humborg C, Mörth CM, Rahm L, Pollehne F (2008) Tracing terrestial organic matter by σ34S and σ13C signatures in a subarctic estuary. Limnol Oceanogr 53(6):2594–2602CrossRefGoogle Scholar
  4. Arvola L, Räike A, Kortelainen P, Järvinen M (2004) The effect of climate and land use on TOC concentrations and loads in Finnish rivers. Boreal Environ Res 9:381–387Google Scholar
  5. Arvola L, Rask M, Ruuhijarvi J, Tulonen T, Vuorenmaa J, Ruoho-Airola T et al (2010) Long-term patterns in pH and colour in small acidic boreal lakes of varying hydrological and landscape settings. Biogeochemistry 101:269–279CrossRefGoogle Scholar
  6. Asmala E, Autio R, Kaartokallio H, Pitkänen L, Stedmon CA, Thomas DN (2013) Bioavailability of riverine dissolved organic matter in three Baltic Sea estuaries and the effect of catchment land-use. Biogeosciences 10:6969–6989CrossRefGoogle Scholar
  7. Asmala E, Autio R, Kaartokallio H, Stedmon CA, Thomas DN (2014) Processing of humic-rich riverine dissolved organic matter by estuarine bacteria: effects of predegradation and inorganic nutrients. Aquat Sci 76(3):451–463CrossRefGoogle Scholar
  8. Aufdenkampe AK, Mayorga E, Raymond PA, Melack JM, Doney SC, Alin SR, Aalto RE, Yoo K (2011) Riverine coupling of biogeochemical cycles between land, oceans, and atmosphere. Front Ecol Environ 9(1):53–60. doi: 10.1890/100014 CrossRefGoogle Scholar
  9. Baker A, Cumberland S, Hudson N (2008) Dissolved and total organic and inorganic carbon in some British rivers. Area 40:117–127CrossRefGoogle Scholar
  10. Battin TJ, Luyssaert S, Kaplan LA, Aufdenkampe AK, Richter A, Tranvik LJ (2009) The boundless carbon cycle. Nat Geosci 2:598–600CrossRefGoogle Scholar
  11. Berglund J, Muren U, Båmstedt U, Anderson A (2007) Efficiency of a phytoplankton and a bacterial-based food web in a pelagic marine system. Limnol Oceanogr 52:121–131CrossRefGoogle Scholar
  12. Brink J, Humborg C, Sahlberg J, Rahm L, Mörth CM (2007) Weathering rates and origin of inorganic carbon as influenced by river regulation in the boreal sub-arctic region of Sweden. Hydrol Earth Syst Sci Discuss 4:555–588CrossRefGoogle Scholar
  13. Cai WJ, Hu XP, Huang WJ, Murrell MC, Lehrter JC, Lohrenz SE, Chou WC, Zhai WD et al (2011) Acidification of subsurface coastal waters enhanced by eutrophication. Nat Geosci 4:766–770. doi: 10.1038/NGEO1297 CrossRefGoogle Scholar
  14. Clair TA, Dennis IF, Vet R, Laudon H (2008) Long–term trends in catchment organic carbon and nitrogen exports from three acidified catchments in Nova Scotia, Canada. Biogeochemistry 87:83–97CrossRefGoogle Scholar
  15. Clark JM, Bottrell SH, Evans CD, Monteith DT, Bartlett R, Rose R et al (2010) The importance of the relationship between scale and process in understanding long-term DOC dynamics. Sci Total Environ 408:2768–2775CrossRefPubMedGoogle Scholar
  16. Cole JJ, Prairie YT, Caraco NF, McDowell WH, Tranvik LJ, Striegl RG et al (2007) Plumbing the global carbon cycle: integrating inland waters into the terrestrial carbon budget. Ecosystems 10:172–185CrossRefGoogle Scholar
  17. Conley D, Carstensen J, Aigars J, Axe P, Bonsdorff E, Eremina T et al (2011) Hypoxia is increasing in the coastal zone of the Baltic Sea. Environ Sci Technol 45(16):6777–6783CrossRefPubMedPubMedCentralGoogle Scholar
  18. de Wit HA, Mulder J, Hindar A, Hole L (2007) Long-term increase in dissolved organic carbon in streamwaters in Norway is response to reduced acid deposition. Environ Sci Technol 41(22):7706–7713CrossRefPubMedGoogle Scholar
  19. de Wit HA, Austnes K, Hylen G, Dalsgaard L (2015) A carbon balance of Norway: terrestrial and aquatic carbon fluxes. Biogeochemistry. doi: 10.1007/s10533-014-0060-5 Google Scholar
  20. del Giorgio PA, Peters RH (1994) Patterns in planktonic P:R ratios in lakes: influence of lake trophy and dissolved organic carbon. Limnol Oceanogr 39:772–787CrossRefGoogle Scholar
  21. Denman KL, Brasseur G, Chidthaisong A, Ciais P, Cox PM, Cox R, et al (2007) Couplings between changes in the climate system and biogeochemistry. In: Solomon S, Qin D, Manning M, Chen Z, Marquis M (eds) Climate change 2007: the physical science basis. Contribution of Working Group 1 to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge University Press, pp 499–587Google Scholar
  22. Downing JA, Prairie YT, Cole JJ, Duarte CM, Tranvik LJ, Striegl RG et al (2006) The global abundance and size distribution of lakes, ponds, and impoundments. Limnol Oceanogr 51:2388–2397CrossRefGoogle Scholar
  23. Edman M, Omstedt A (2013) Modeling the dissolved CO2 system in the redox environment of the Baltic Sea. Limnol Oceanogr 58(1):74–92CrossRefGoogle Scholar
  24. Eimers MC, Watmough SA, Buttle JM (2008) Long–term trends in dissolved organic carbon concentration: a cautionary note. Biogeochemistry 87:71–81CrossRefGoogle Scholar
  25. Evans CD, Monteith DT, Cooper DM (2005) Long-term increases in surface water dissolved organic carbon: Observations, possible causes and environmental impacts. Environ Pollut 137:55–71CrossRefPubMedGoogle Scholar
  26. Evans CD, Chapman PJ, Clark JM, Monteith DT, Cresser MS (2006) Alternative explanations for rising dissolved organic carbon export from organic soils. Glob Change Biol 12:2044–2053CrossRefGoogle Scholar
  27. Evans CD, Jones TG, Burden A, Ostle N, Zielinski P, Cooper M et al (2012) Acidity controls on dissolved organic carbon mobility in organic soils. Global Change Biology. doi: 10.1111/j.1365-2486.2012.02794.x
  28. Fleming-Lehtinen V, Räike A, Kortelainen P, Kauppila P, Thomas D (2015) Organic carbon concentration in the northern coastal Baltic Sea between 1975 and 2011. Estuaries Coasts 38:466–481CrossRefGoogle Scholar
  29. Freeman C, Evans CD, Monteith DT, Reynolds B, Fenner N (2001) Export of organic carbon from peat soils. Nature 412:785CrossRefPubMedGoogle Scholar
  30. Futter M, Valinia S, Löfgren S, Köhler SJ, Fölster J (2014) Long-term trends in water chemistry of acid-sensitive Swedish lakes show slow recovery from historic acidification. Ambio 43:77–90CrossRefPubMedPubMedCentralGoogle Scholar
  31. Garmo OA, Skjelkvåle BL, de Wit HA, Colombo L, Curtis C, Fölster J, Hoffmann A, Hruška J et al (2014) Trends in surface water chemistry in acidified areas in Europe and North America from 1990 to 2008. Water Air Soil Pollut 225:1880. doi: 10.1007/s11270-014-1880-6
  32. Graham LP (2004) Climate change effects on river flow to the Baltic Sea. Ambio 33:235–241CrossRefPubMedGoogle Scholar
  33. Guo L, Cai Y, Belzile C, Macdonald RW (2012) Sources and export fluxes of inorganic and organic carbon and nutrient species from the seasonally ice-covered Yukon River. Biogeochemistry 107:187–206. doi: 10.1007/s10533-010-9545-z CrossRefGoogle Scholar
  34. Heino R, Tuomenvirta H, Vuglinsky VS, Gustafsson BG, Alexandersson H, et al (2008) Past and current climate change. In: Bolle H–J, Menenti M, Rasool I (eds) Assessment of climate change for the Baltic Sea basin. Regional climate studies. Springer, Berlin, pp 35–131Google Scholar
  35. HELCOM (2009) Eutrophication in the Baltic Sea—an integrated thematic assessment of the effects of nutrient enrichment and eutrophication in the Baltic Sea region. In: Balt Sea Environ Proc No. 115BGoogle Scholar
  36. Hirsch RM, Slack JR, Smith RA (1982) Techniques of trend analysis for monthly water quality data. Water Resour Res 18:107–121CrossRefGoogle Scholar
  37. Hirsch RM, Alexander RB, Smith RA (1991) Selection of methods for the detection and estimation of trends in water quality. Water Resour Res 27:803–813CrossRefGoogle Scholar
  38. Hjalmarsson S, Wesslander K, Anderson LG, Omstedt A, Perttilä M, Mintrop L (2008) Distribution, long-term development and mass balance calculation of total alkalinity in the Baltic Sea. Cont Shelf Res 28:593–601CrossRefGoogle Scholar
  39. Hoikkala L, Kortelainen P, Soinne H, Kuosa H (2015) Dissolved organic matter in the Baltic Sea. J Marine Systems 142:47–61CrossRefGoogle Scholar
  40. Humborg C, Mörth CM, Sundbom M, Borg H, Bleckner T, Giesler R, Ittekkot V (2010) CO2 supersaturation along the aquatic conduit in Swedish watersheds as constrained by terrestrial respiration, aquatic respiration and weathering. Glob Change Biol 16:1966–1978. doi: 10.1111/j.1365-2486.2009.02092.x CrossRefGoogle Scholar
  41. Jutterström S, Andersson HC, Omstedt A, Malmaeus JM (2014) Multiple stressors threatening the future of the Baltic Sea-Kattegat marine ecosystem: implications for policy and management actions. Mar Pollut Bull 86:468–480CrossRefPubMedGoogle Scholar
  42. Jylhä K, Tuomenvirta H, Ruosteenoja K (2004) Climate change projections for Finland during the 21st century. Boreal Environ Res 9:127–152Google Scholar
  43. Köhler S, Buffam I, Jonsson A, Bishop K (2002) Photochemical and microbial processing of stream and soil water dissolved organic matter in a boreal forested catchment in northern Sweden. Aquat Sci 64:269–281CrossRefGoogle Scholar
  44. Kortelainen P, Rantakari M, Huttunen JT, Mattsson T, Alm J, Juutinen S, Larmola T, Silvola J, Martikainen PJ (2006) Sediment respiration and lake trophic state are important predictors of large CO2 evasion from small boreal lakes. Glob Change Biol 12:1554–1567. doi: 10.1111/j.1365-2486.2006.01167.x CrossRefGoogle Scholar
  45. Krug EC, Frink CR (1983) Acid rain on acid soil: a new perspective. Science 211:520–525CrossRefGoogle Scholar
  46. Kulinski K, Pempkowiak J (2012) Carbon cycling in the Baltic Sea (Geoplanet: Earth and Planetary Sciences). Springer, BerlinCrossRefGoogle Scholar
  47. Lahermo P, Väänänen P, Tarviainen T, Salminen R (1996) Geochemical atlas of Finland, Part 3: environmental geochemistry—stream waters and sediments. Geological Survey of Finland, Espoo, EspooGoogle Scholar
  48. Laudon H, Berggren M, Ågren A, Buffam I, Bishop K, Grabs T et al (2011) Patterns and dynamics of dissolved organic carbon (DOC) in boreal streams: the role of processes, connectivity, and scaling. Ecosystems 14:880–893CrossRefGoogle Scholar
  49. Lehtoranta J, Ekholm P, Pitkänen H (2009) Coastal eutrophication thresholds: a matter of sediment microbial processes. Ambio 38(6):303–308CrossRefPubMedGoogle Scholar
  50. Lepistö A, Kortelainen P, Mattsson T (2008) Increased organic C and N leaching in a northern boreal river basin in Finland. Glob Biogeochem Cycle 22:GB3029Google Scholar
  51. Lepistö L, Futter M, Kortelainen P (2014) Almost 50 years of monitoring shows that climate, not forestry, controls long-term organic carbon fluxes in a large boreal watershed. Glob Change Biol 20:1225–1237. doi: 10.1111/gcb.12491 CrossRefGoogle Scholar
  52. Libiseller C, Grimvall A (2002) Performance of partial Mann-Kendall tests for trend detection in the presence of covariates. Environmetrics 13:71–84CrossRefGoogle Scholar
  53. Löfgren S, Zetterberg T (2011) Decreased DOC concentrations in soil water in forested areas in southern Sweden during 1987–2008. Sci Total Environ 409:1916–1926CrossRefPubMedGoogle Scholar
  54. Mattsson T, Kortelainen P, Raike A (2005) Export of DOM from boreal catchments: impacts of land use cover and climate. Biogeochemistry 76:373–94Google Scholar
  55. Mattsson T, Kortelainen P, Räike A, Lepistö A, Thomas DN (2015) Spatial and temporal variability of organic C and N concentrations and export from 30 boreal rivers induced by land use and climate. Sci Total Environ 508:145–154CrossRefPubMedGoogle Scholar
  56. Meybeck M (1987) Global chemical weathering of surficial rocks estimated from river dissolved loads. Am J Sci 287:401–428CrossRefGoogle Scholar
  57. Meybeck M (1993) Riverine transport of atmospheric carbon: sources, global typology and budget. Water Air Soil Pollut 70:443–463CrossRefGoogle Scholar
  58. Miller WL, Moran MA (1997) Interaction of photochemical and microbial processes in the degradation of refractory dissolved organic matter from a coastal marine environment. Limnol Oceanogr 42(6):1317–1324CrossRefGoogle Scholar
  59. Millot R, Gaillardet J, Dupre B, Allegre CJ (2003) Northern latitude chemical weathering rates: clues from the Mackenzie River Basin, Canada. Geochim Cosmochim Acta 67(7):1305–1329CrossRefGoogle Scholar
  60. Monteith DT, Stoddard JL, Evans CD, De Wit HA, Forsius M, Hoegaasen T et al (2007) Dissolved organic carbon trends resulting from changes in atmospheric deposition chemistry. Nature 450:537–540CrossRefPubMedGoogle Scholar
  61. Omstedt A, Edman M, Claremar B, Frodin P, Gustafsson E, Humborg C, Hägg H, Mörth M (2012) Future changes in the Baltic Sea acid-base (pH) and oxygen balances. Tellus Ser B 64:1–23CrossRefGoogle Scholar
  62. Räike A, Pietiläinen OP, Rekolainen S, Kauppila P, Pitkänen H, Niemi J, Raateland A, Vuorenmaa J (2003) Trends of phosphorus, nitrogen and chlorophyll a concentrations in Finnish rivers and lakes in 1975–2000. Sci Total Environ 310:47–59CrossRefPubMedGoogle Scholar
  63. Räike A, Kortelainen P, Mattsson T, Thomas DN (2012) 36 year trends in dissolved organic carbon export from Finnish rivers to the Baltic Sea. Sci Total Environ 435–436:188–201CrossRefPubMedGoogle Scholar
  64. Rantakari M, Kortelainen P (2005) Interannual variation and climatic regulation of the CO2 emission from large boreal lakes. Glob Change Biol 11:1368–1380. doi: 10.1111/j.1365-2486.2005.00982x CrossRefGoogle Scholar
  65. Rantakari M, Kortelainen P (2008) Controls of organic and inorganic carbon in randomly selected Boreal lakes in varied catchments. Biogeochemistry 91:151–162CrossRefGoogle Scholar
  66. Rantakari M, Mattsson T, Kortelainen P, Piirainen S, Finér L, Ahtiainen M (2010) Organic and inorganic carbon concentrations and fluxes from managed and unmanaged boreal first-order catchments. Sci Total Environ 408(7):1649–1658CrossRefPubMedGoogle Scholar
  67. Raymond PA, Cole JJ (2003) Increase in the export of alkalinity from North America’s largest river. Science 301:88–91. doi: 10.1126/science.1083788 CrossRefPubMedGoogle Scholar
  68. Reichstein M, Bednorz F, Broll G, Kätterer T (2000) Temperature dependence of carbon mineralisation: conclusions from a long-term incubation of subalpine soil samples. Soil Biol Biochem 32:948–958CrossRefGoogle Scholar
  69. Sarkkola S, Koivusalo H, Laurén A, Kortelainen P, Mattsson T, Palviainen M, Piirainen S, Starr M, Finér L (2009) Trends in hydrometeorological conditions and stream water organic carbon in boreal forested catchments. Sci Total Environ 408:92–101CrossRefPubMedGoogle Scholar
  70. Settele J, Scholes R, Betts R, Bunn S, Leadley P, Nepstad D, Overpeck JT, Taboada MA (2014) Terrestrial and inland water systems. In: Field CB, Barros VR, Dokken DJ, Mach KJ, Mastrandrea MD, Bilir TE, Chatterjee M, Ebi KL et al (eds) Climate change 2014: impacts, adaptation, and vulnerability. Part A: Global and sectoral aspects. Contribution of Working Group II to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA, pp 271–359Google Scholar
  71. Smith B, Aasa A, Ahas R, Bleckner T, Callaghan TV (2008) Climate related change in terrestrial and freshwater ecosystems. In: Menenti M, Rasool I, Bolle H-J (eds) Assessment of climate change for the Baltic Sea basin. Regional climate studies. Springer, Berlin, pp 221–307CrossRefGoogle Scholar
  72. Starr M, Lindroos AJ, Tarvainen T, Tanskanen H (1998) Weathering rates in the Hietajärvi Integrated Monitoring catchment. Boreal Environ Res 3:275–285Google Scholar
  73. Stets EG, Striegl RG (2012) Carbon export by rivers draining the conterminous United States. Inland Waters 2:177–184CrossRefGoogle Scholar
  74. Stets EG, Kelly VJ, Crawford CG (2014) Long-term trends in alkalinity in large rivers of the conterminous US in relation to acidification, agriculture, and hydrologic modification. Sci Total Environ 488–489:280–289CrossRefPubMedGoogle Scholar
  75. Stoddard JL, Jeffries DS, Lukewille A, Clair TA, Dillon PJ, Driscoll CT et al (1999) Regional trends in aquatic recovery from acidification in North America and Europe. Nature 401:575–578. doi: 10.1038/44114 CrossRefGoogle Scholar
  76. Striegl RG, Dornblaser MM, Aiken GR, Wickland KP, Raymond PA (2007) Carbon export and cycling by the Yukon, Tanana, and Porcupine rivers, Alaska, 2001–2005. Wat Resour Res 43. doi: 10.1029/2006WR005201
  77. Sundquist ET (1993) The global carbon dioxide budget. Science 259:934–941CrossRefGoogle Scholar
  78. Tank SE, Raymond PA, Striegl RG, McClelland JW, Holmes RM, Fiske GJ, Peterson BJ (2012) A land-to-ocean perspective on the magnitude, source and implication of DIC flux from major Arctic rivers to the Arctic Ocean. Global Biogeochem Cycles 26:GB4018. doi: 10.1029/2011GB004192
  79. Thrane JE, Hessen DO, Andersen T (2014) The absorption of light in lakes: negative impact of dissolved organic carbon on primary productivity. Ecosystems 17(6):1040–1062CrossRefGoogle Scholar
  80. Tranvik LJ, Downing JA, Cotner JB, Loiselle SA, Striegl RG, Ballatore TJ et al (2009) Lakes and reservoirs as regulators of carbon cycling and climate. Limnol Oceanogr 54:2298–2314Google Scholar
  81. Veijalainen N (2012) Estimation of climate change impacts on hydrology and floods in Finland. Doctoral dissertations/Aalto University publication series 55 Aalto University publication series/Doctoral dissertations, ISSN 1799-4942Google Scholar
  82. Vuorenmaa J (2004) Long-term changes of acidifying deposition in Finland (1973–2000). Environ Poll 128:351–362CrossRefGoogle Scholar
  83. Vuorenmaa J, Forsius M, Mannio J (2006) Increasing trends of total organic carbon concentrations in small forest lakes in Finland from 1987 to 2003. Sci Total Environ 365:47–65CrossRefPubMedGoogle Scholar
  84. Weyhenmeyer G, Fröberg M, Karltun E, Khalili M, Kothawala D, Temnerud J, Tranvik LJ (2012) Selective decay of terrestrial organic carbon during transport from land to sea. Glob Change Biol 18:349–355CrossRefGoogle Scholar
  85. Worrall F, Burt TP (2007) Flux of dissolved organic carbon from UK rivers. Glob Biogeochem Cycle 21:GB1013Google Scholar
  86. Worrall F, Burt T, Shedden R (2003) Long term records of riverine dissolved organic matter. Biogeochemistry 64:165–178CrossRefGoogle Scholar
  87. Zakharova EA, Pokrovsky OS, Dupré B, Gaillardet J, Efimova LE (2007) Chemical weathering of silicate rocks in Karelia region and Kola peninsula, NW Russia: assessing the effect of rock composition, wetlands and vegetation. Chem Geol 242:255–277CrossRefGoogle Scholar

Copyright information

© Springer International Publishing 2015

Authors and Affiliations

  • Antti Räike
    • 1
    Email author
  • Pirkko Kortelainen
    • 1
  • Tuija Mattsson
    • 1
  • David N. Thomas
    • 1
    • 2
  1. 1.Finnish Environment Institute (SYKE)HelsinkiFinland
  2. 2.School of Ocean SciencesBangor UniversityAngleseyUK

Personalised recommendations