Differential controls on CO2 and CH4 emissions from the free-flowing Neretva River, Bosnia and Herzegovina


  • Martin Dalvai Ragnoli Department of Ecology, University of Innsbruck, 6020 Innsbruck
  • Thea Schwingshackl Department of Ecology, University of Innsbruck, 6020 Innsbruck
  • Serafine Kattus Department of Ecology, University of Innsbruck, 6020 Innsbruck
  • Julius Lissy Department of Ecology, University of Innsbruck, 6020 Innsbruck
  • Elisabeth Weninger Department of Ecology, University of Innsbruck, 6020 Innsbruck
  • Gabriel Singer Department of Ecology, University of Innsbruck, 6020 Innsbruck




dams, gas transfer velocity, greenhouse gas, greenhouse gas footprint of hydropower, emission fluxes, pristine reference river


Streams and rivers emit methane (CH4) and carbon dioxide (CO2), two greenhouse gasses contributing to global warming. Estimates for diffusive gas emissions can be obtained by multiplying the concentration gradient between water and atmosphere with the gas transfer velocity. The latter is purely physically constrained, yet spatially highly variable. And - in a flowing water ecosystem - the local concentration gradient is the result of a dynamic balance between upstream evasion and resupply. The collection of representative emission data is thus challenging and emissions of river ecosystems are rarely assessed considering temporal variability and spatial dependence at network scale. In this study, we uncover spatial heterogeneity and controls of concentrations and emission fluxes of the two greenhouse gasses, CH4 and CO2, along a 50 km length of a pristine river system, the Neretva River in Bosnia and Herzegovina. This remote river network has so far remained barely influenced by human activities and the hydromorphological status is to date not altered. The Neretva can therefore serve as a reference for similar systems in the region. This seems to be particularly important as rivers in the Western Balkans, including the Neretva, are currently experiencing a surge in hydropower development and damming, which is known to strongly affect riverine greenhouse gas emissions. We found high emissions as a result of co-occurrence of high concentration with high exchange velocity, but we identified different underlying mechanistic processes driving the evasion of the two gasses. CH4 was strongly supply-limited: elevated concentrations were exclusively measured in a large pool (0.84 µmol L-1 compared to a median concentration of 0.005 µmol L-1 in the entire study section). This resulted in CH4 evasion being four orders of magnitude higher in the turbulent reach following the pool (22 mmol m-2 d-1) compared to the median evasion at network scale (0.06 mmol m-2 d-1). In contrast, CO2 evasion was more variable in time and equally dependent on CO2 and gas exchange velocity. The construction of dams intended in this area would lead to reservoirs of slowly flowing or standing water with similar habitat conditions as the observed CH4-hotspot. The concomitant increase in residence time and higher retention of organic material will lead to an increase of CH4 production replacing aerobic respiration. Consequently, CH4 emissions can be expected to drastically increase by orders of magnitude. This greenhouse gas footprint of hydropower generation may counteract the promised climate benefits in terms of renewable energy production.


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. Frontiers in Ecology and the Environment. 9(1): 53–60. https://doi.org/10.1890/100014 DOI: https://doi.org/10.1890/100014

Baker MA, Dahm CN, Valett HM. 1999. Acetate retention and metabolism in the hyporheic zone of a mountain stream. Limnology and Oceanography. 44(6): 1530–1539. https://doi.org/10.4319/lo.1999.44.6.1530 DOI: https://doi.org/10.4319/lo.1999.44.6.1530

Bastviken D. 2009. Methane. In Encyclopedia of Inland Waters. p. 783–805. Elsevier Inc. https://doi.org/10.1016/B978-012370626-3.00117-4 DOI: https://doi.org/10.1016/B978-012370626-3.00117-4

Butman D, Raymond PA. 2011. Significant efflux of carbon dioxide from streams and rivers in the United States. Nature Geoscience. 4(12): 839–842. https://doi.org/10.1038/ngeo1294 DOI: https://doi.org/10.1038/ngeo1294

Ceola S, Enrico B, Singer G, Battin TJ, Montanari A, Rinaldo A. 2014. Hydrologic controls on basin-scale distribution of benthic invertebrates. Water Resources Research. 50. https://doi.org/doi:10.1002/2013WR015112 DOI: https://doi.org/10.1002/2013WR015112

Chamberlain L. 2018. Eco-Masterplan for Balkan Rivers. Drawing a line in the Sand.

Crawford JT, Dornblaser MM, Stanley EH, Clow DW, Striegl RG. 2015. Source limitation of carbon gas emissions in high-elevation mountain streams and lakes. Journal of Geophysical Research: Biogeosciences. 120: 952–964. https://doi.org/10.1002/2014JG002861 DOI: https://doi.org/10.1002/2014JG002861

Crawford JT, Loken LC, West WE, Crary B, Spawn SA, Gubbins N, Jones SE, Striegl RG, Stanley EH. 2017. Spatial heterogeneity of within-stream methane concentrations. Journal of Geophysical Research: Biogeosciences. 122(5): 1036–1048. https://doi.org/10.1002/2016JG003698 DOI: https://doi.org/10.1002/2016JG003698

Crawford JT, Stanley EH. 2016. Controls on methane concentrations and fluxes in streams draining human‐dominated landscapes. Ecological Applications. 26(5): 1581–1591. https://doi.org/10.1890/15-1330 DOI: https://doi.org/10.1890/15-1330

Crawford JT, Striegl RG, Wickland KP, Dornblaser MM, Stanley EH. 2013. Emissions of carbon dioxide and methane from a headwater stream network of interior Alaska. Journal of Geophysical Research: Biogeosciences. 118(2): 482–494. https://doi.org/10.1002/jgrg.20034 DOI: https://doi.org/10.1002/jgrg.20034

Crawford JT, Stanley EH, Spawn SA, Finlay JC, Loken LC, Striegl RG. 2014. Ebullitive methane emissions from oxygenated wetland streams. Global Change Biology. 20(11): 3408–3422. https://doi.org/10.1111/gcb.12614 DOI: https://doi.org/10.1111/gcb.12614

Copernicus. 2022. DEM Global and European Digital Elevation Model; [accessed 2022 May 1]. https://doi.org/10.5270/ESA-c5d3d65 DOI: https://doi.org/10.5270/ESA-c5d3d65

Del Campo R, Jechsmayr B, Settles V, Ströder M, Singer G. 2023. Nutrient inputs shape ecosystem functioning gradients along the pristine, upper Neretva River, Bosnia and Herzegovina. Natura Sloveniae. 25(3): 239-263.

DIKTAS B&H. 2012. Protection and Sustainable Use of the Dinaric Karst Transboundary Aquifer System. https://docslib.org/doc/9481960/protection-and-sustainable-use-of-the-dinaric-karst-transboundary-aquifer-system

Dinsmore KJ, Billett MF. 2008. Continuous measurement and modeling of CO2 losses from a peatland stream during stormflow events. Water Resources Research. 44(12). https://doi.org/10.1029/2008WR007284 DOI: https://doi.org/10.1029/2008WR007284

Djedjibegovic, J, Marjanovi A, Sober M, Skrbo A, Sinanovic K, Larssen T et al. 2010. Levels of persistent organic pollutants in the Neretva River (Bosnia and Herzegovina) determined by deployment of semipermeable membrane devices (SPMD). Journal of environmental science and health, Part B. 45: 128–136. DOI: https://doi.org/10.1080/03601230903472017

Drake TW, Raymond PA, Spencer RGM. 2018. Terrestrial carbon inputs to inland waters: A current synthesis of estimates and uncertainty. Limnology and Oceanography Letters. 3(3): 132–142. https://doi.org/10.1002/lol2.10055 DOI: https://doi.org/10.1002/lol2.10055

Duvert C, Butman DE, Marx A, Ribolzi O, Hutley LB. 2018. CO2 evasion along streams driven by groundwater inputs and geomorphic controls. Nature Geoscience. 11(11): 813–818. https://doi.org/10.1038/s41561-018-0245-y DOI: https://doi.org/10.1038/s41561-018-0245-y

Flury S, Ulseth AJ. 2019. Exploring the Sources of Unexpected High Methane Concentrations and Fluxes From Alpine Headwater Streams. Geophysical Research Letters. 46(12): 6614–6625. https://doi.org/10.1029/2019GL082428 DOI: https://doi.org/10.1029/2019GL082428

Gómez-Gener L, Rocher-ros G, Battin T, Cohen MJ, Dalmagro HJ, Dinsmore KJ, Drake TW, Duvert C, Enrich-prast A, Horgby Å, Johnson MS, Kirk L, Machado-silva F, Marzolf NS, Mcdowell MJ, Mcdowell WH, Miettinen H, Ojala AK, Peter H, … Six, J. 2021. Global carbon dioxide efflux from rivers enhanced by high nocturnal emissions. Nature Geoscience. 14(5). https://doi.org/10.1038/s41561-021-00722-3 DOI: https://doi.org/10.1038/s41561-021-00722-3

Grego J. 2020. Revision of the stygobiont gastropod genera Plagigeyeria (Tomlin, 1930) and Travunijana (Grego an Glöer, 2019) (Mollusca; Gastropoda; Moitessieriidae and Hydrobiidae) in Hercegovina and adjacent regions. European Journal of Taxonomy. 2020(691): 1–56. https://doi.org/10.5852/EJT.2020.691 DOI: https://doi.org/10.5852/ejt.2020.691

Hartmann J, Lauerwald R, Moosdorf N. 2014. A brief overview of the GLObal RIver Chemistry Database. GLORICH. Procedia Earth and Planetary Science. 10: 23–27. https://doi.org/10.1016/j.proeps.2014.08.005 DOI: https://doi.org/10.1016/j.proeps.2014.08.005

Horgby Å, Boix Canadell M, Ulseth AJ, Vennemann TW, Battin TJ. 2019. High-resolution spatial sampling identifies groundwater as driver of CO2 dynamics in an alpine stream network. Journal of Geophysical Research: Biogeosciences. 124(7): 1961–1976. https://doi.org/10.1029/2019JG005047 DOI: https://doi.org/10.1029/2019JG005047

Hotchkiss ER, Hall RO, Sponseller RA, Butman D, Klaminder J, Laudon H, Rosvall M, Karlsson J. 2015. Sources of and processes controlling CO2 emissions change with the size of streams and rivers. Nature Geoscience. 8(9): 696–699. https://doi.org/10.1038/ngeo2507 DOI: https://doi.org/10.1038/ngeo2507

[IHA] International Hydropower Association. 2010. GHG measurement guidelines for freshwater reservoirs. Editor Joel A. Goldenfum. International Hydropower Association, London, UK.

Jähne B, Heinz G, Dietrich W. 1987. Measurement of the diffusion coefficients of sparingly soluble gases in water. Journal of Geophysical Research. 92(C10): 10767. https://doi.org/10.1029/JC092iC10p10767 DOI: https://doi.org/10.1029/JC092iC10p10767

Johnson MS, Weiler M, Couto EG, Riha SJ, Lehmann J. 2007. Storm pulses of dissolved CO2 in a forested headwater Amazonian stream explored using hydrograph separation. Water Resources Research. 43(11). https://doi.org/10.1029/2007WR00635 DOI: https://doi.org/10.1029/2007WR006359

Leach JA, Lidberg W, Kuglerová L, Peralta-Tapia A, Ågren A, Laudon H. 2017. Evaluating topography-based predictions of shallow lateral groundwater discharge zones for a boreal lake-stream system. Water Resources Research. 53(7): 5420–5437. https://doi.org/10.1002/2016WR019804 DOI: https://doi.org/10.1002/2016WR019804

Ledesma JLJ, Futter MN, Blackburn M, Lidman F, Grabs T, Sponseller RA, Laudon H, Bishop KH, Köhler SJ. 2018. Towards an improved conceptualization of riparian zones in boreal forest headwaters. Ecosystems. 21(2): 297–315. https://doi.org/10.1007/s10021-017-0149-5 DOI: https://doi.org/10.1007/s10021-017-0149-5

Leopold L, Wolman M, J M. 1964. Fluvial processes in geomorphology.

Lupon A, Denfeld BA, Laudon H, Leach J, Karlsson J, Sponseller RA. 2019. Groundwater inflows control patterns and sources of greenhouse gas emissions from streams. Limnology and Oceanography. 64(4): 1545–1557. https://doi.org/10.1002/lno.11134 DOI: https://doi.org/10.1002/lno.11134

Maeck A, Delsontro T, McGinnis DF, Fischer H, Flury S, Schmidt M, Fietzek P, Lorke A. 2013. Sediment trapping by dams creates methane emission hot spots. Environmental Science and Technology. 47(15): 8130–8137. https://doi.org/10.1021/es4003907 DOI: https://doi.org/10.1021/es4003907

McGinnis DF, Bilsley N, Schmidt M, Fietzek P, Bodmer P, Premke K, Lorke A, Flury S. 2016. Deconstructing methane emissions from a small Northern European river: hydrodynamics and temperature as key drivers. Environmental Science and Technology. 50(21): 11680–11687. https://doi.org/10.1021/acs.est.6b03268 DOI: https://doi.org/10.1021/acs.est.6b03268

Operta M, Pamuk S. 2015. Geological characteristics and tectonic structure of the upper Neretva basin. Acta geographica Bosniae et Herzegovinae. p. 63–74.

Peter H, Singer GA, Preiler C, Chifflard P, Steniczka G, Battin TJ. 2014. Scales and drivers of temporal pCO2 dynamics in an Alpine stream. Journal of Geophysical Research: Biogeosciences. 119(6): 1078–1091. https://doi.org/10.1002/2013JG002552 DOI: https://doi.org/10.1002/2013JG002552

Rasilo T, Hutchins RHS, Ruiz-González C, del Giorgio PA. 2017. Transport and transformation of soil-derived CO2, CH4 and DOC sustain CO2 supersaturation in small boreal streams. Science of the Total Environment. 579: 902–912. https://doi.org/10.1016/j.scitotenv.2016.10.187 DOI: https://doi.org/10.1016/j.scitotenv.2016.10.187

Raymond PA, Hartmann J, Lauerwald R, Sobek S, McDonald C, Hoover M, Butman D, Striegl R, Mayorga E, Humborg C, Kortelainen P, Dürr H, Meybeck M, Ciais P, Guth P. 2013. Global carbon dioxide emissions from inland waters. Nature. 503(7476): 355–359. https://doi.org/10.1038/nature12760 DOI: https://doi.org/10.1038/nature12760

Raymond PA, Zappa CJ, Butman D, Bott TL, Potter J, Mulholland P, Laursen AE, McDowell WH, Newbold D. 2012. Scaling the gas transfer velocity and hydraulic geometry in streams and small rivers. Limnology and Oceanography: Fluids and Environments. 2(1): 41–53. https://doi.org/10.1215/21573689-1597669 DOI: https://doi.org/10.1215/21573689-1597669

Rocher‐Ros G, Sponseller RA, Lidberg W, Mört, C, Giesler R. 2019. Landscape process domains drive patterns of CO 2 evasion from river networks. Limnology and Oceanography Letters. 4(4): 87–95. https://doi.org/10.1002/lol2.10108 DOI: https://doi.org/10.1002/lol2.10108

Stanley EH, Casson NJ, Christel ST, Crawford JT, Loken LC, Oliver SK. 2016. The ecology of methane in streams and rivers: patterns, controls, and global significance. Ecological Monographs. 86(2): 146–171. https://doi.org/10.1890/15-1027 DOI: https://doi.org/10.1890/15-1027

Talluto MV. 2020. WatershedTools: An R package for the spatial analysis of watersheds. version 0.4.9, https://github.com/flee-group/watershed

Valdes D, Dupont JP, Laignel B, Ogier S, Leboulanger T, Mahler BJ. 2007. A spatial analysis of structural controls on Karst groundwater geochemistry at a regional scale. Journal of Hydrology. 340(3–4): 244–255. https://doi.org/10.1016/j.jhydrol.2007.04.014 DOI: https://doi.org/10.1016/j.jhydrol.2007.04.014

Wallin MB, Campeau A, Audet J, Bastviken D, Bishop K, Kokic J, Laudon H, Lundin E, Löfgren S, Natchimuthu S, Sobek S, Teutschbein C, Weyhenmeyer GA, Grabs T. 2018. Carbon dioxide and methane emissions of Swedish low‐order streams—a national estimate and lessons learnt from more than a decade of observations. Limnology and Oceanography Letters. 3(3): 156–167. https://doi.org/10.1002/lol2.10061 DOI: https://doi.org/10.1002/lol2.10061

Wilkinson J, Bors C, Burgis F, Lorke A, Bodmer P. 2018. Measuring CO 2 and CH 4 with a portable gas analyzer: Closed-loop operation, optimization and assessment. PLoS ONE. 13(4): 1–16. https://doi.org/10.1371/journal.pone.0193973 DOI: https://doi.org/10.1371/journal.pone.0193973

Xiao S, Liu L, Wang W, Lorke A, Woodhouse J. 2020. A Fast-Response Automated Gas Equilibrator (FaRAGE) for continuous in situ measurement of CH4 and CO2 dissolved in water. Hydrology and Earth System Sciences. 24(7): 3871–3880. https://doi.org/10.5194/hess-24-3871-2020 DOI: https://doi.org/10.5194/hess-24-3871-2020

Yang L, Lu F, Zhou X, Wang X, Duan X, Sun B. 2014. Progress in the studies on the greenhouse gas emissions from reservoirs. Acta Ecologica Sinica. 34(4): 204–212. https://doi.org/10.1016/j.chnaes.2013.05.01 DOI: https://doi.org/10.1016/j.chnaes.2013.05.011




How to Cite

Dalvai Ragnoli, M., Schwingshackl, T., Kattus, S., Lissy, J., Weninger, E., & Singer, G. (2023). Differential controls on CO2 and CH4 emissions from the free-flowing Neretva River, Bosnia and Herzegovina. Natura Sloveniae, 25(3), 213-237. https://doi.org/10.14720/ns.25.3.213-237

Similar Articles

11-20 of 73

You may also start an advanced similarity search for this article.