[en] We report dissolved CO2, CH4 and N2O concentrations in two large East African Rift lakes, Edward (surface area 2,325 km2, average depth of 37 m) and George (surface area 273 km2, average depth of 2 m). Lake George showed modest seasonal and spatial variations, and lower partial pressure of CO2 (pCO2) (26±16 ppm, mean±standard deviation), CH4 (234±208 nmol L-1) and N2O saturation levels (%N2O) (80±9%) than Lake Edward (404±145 ppm, 357±483 nmol L-1, 139±222%). Surface waters in both lakes were over-saturated in CH4, and Lake George was under-saturated in CO2 while Lake Edward was slightly over-saturated in CO2. This difference was related to higher phytoplankton biomass in Lake George than Lake Edward, with average chlorophyll-a concentrations of 177±125 and 18±25 µg L-1, respectively. Permanent high cyanobacterial biomass in Lake George led to uniform dissolved CO2, CH4 and N2O concentrations. In surface waters of Lake Edward, spatial variations of pCO2, CH4 and N2O were related to bottom depth, and locally (in particular in Katwe Bay) also related to the inputs of water from Lake George via the Kazinga Channel, a 40-km natural channel connecting the lakes. Short-term mixing events related to storms increased CO2, CH4 and N2O content in surface waters, in particular for CH4 and N2O. This indicates that mixing events in response to storms can create ‘hot moments’ for CH4 and N2O emissions to the atmosphere in tropical lakes, given the weaker vertical density gradients compared to higher latitude systems.
Research center :
FOCUS - Freshwater and OCeanic science Unit of reSearch - ULiège
Disciplines :
Aquatic sciences & oceanology
Author, co-author :
Borges, Alberto ; Université de Liège - ULiège > Département d'astrophysique, géophysique et océanographie (AGO) > Chemical Oceanography Unit (COU)
Okello, William
Bouillon, Steven
Deirmendjian, Loris
Nankabirwa, Angela
Nabafu, Erina
Lambert, Thibault
Descy, Jean-Pierre ; Université de Liège - ULiège > Département d'astrophysique, géophysique et océanographie (AGO) > Chemical Oceanography Unit (COU)
Morana, Cédric ; Université de Liège - ULiège > Département d'astrophysique, géophysique et océanographie (AGO) > Chemical Oceanography Unit (COU)
Language :
English
Title :
Spatial and temporal variations of dissolved CO2, CH4 and N2O in Lakes Edward and George (East Africa)
Abraham, J., Allen, P.M., Dunbar, J.A., Dworkin, S.I., Sediment type distribution in reservoirs: sediment source versus morphometry. Env. Geol. 38 (1999), 101–110.
Abril, G., Guérin, F., Richard, S., Delmas, R., Galy-Lacaux, C., Gosse, P., Tremblay, A., Varfalvy, L., Aurelio Dos Santos, M., Matvienko, B., 2005. Carbon dioxide and methane emissions and the carbon budget of a 10-year old tropical reservoir (Petit Saut, French Guiana). Global Biogeochem. Cycles 19, GB4007, 10.1029/2005GB002457.
Abril, G., Bouillon, S., Darchambeau, F., Teodoru, C.R., Marwick, T.R., Tamooh, F., Omengo, F.O., Geeraert, N., Deirmendjian, L., Polsenaere, P., Borges, A.V., Technical note: Large overestimation of pCO2 calculated from pH and alkalinity in acidic, organic-rich freshwaters. Biogeosciences 12 (2015), 67–78.
Amaral, J.H.F., Borges, A.V., Melack, J.M., Sarmento, H., Barbosa, P.M., Kasper, D., Melo, M.L., de Fex Wolf, D., da Silva, J.S., Forsberg, B.R., Influence of plankton metabolism and mixing depth on CO2 dynamics in an Amazon floodplain lake. Sci. Total Env. 630 (2018), 1381–1393.
Amaral, J.H.F., Melack, J.M., Barbosa, P.M., Borges, A.V., Kasper, D., Cortes, A.C., Zhou, W., MacIntyre, S., Forsberg, B.R., Inundation, hydrodynamics and vegetation influences carbon dioxide concentrations in Amazon floodplain lakes. Ecosystems 25 (2022), 911–930, 10.1007/s10021-021-00692-y.
Apha, Standard Methods for the Examination of Water and Wastewater. 1998, American Public Health Association, Washington DC.
Aufdenkampe, A.K., Mayorga, E., Raymond, P.A., Melack, J.M., Doney, S.C., Alin, S.R., Aalto, R.E., Yoo, K., Riverine coupling of biogeochemical cycles between land, oceans, and atmosphere. Front. Ecol. Environ. 9 (2011), 53–60.
Augusto-Silva, P.B., MacIntyre, S., de Moraes Rudorff, C., Cortés, A., Melack, J.M., Stratification and mixing in large shallow lakes along the lower Amazon River floodplain. J. Great Lakes Res. 45 (2019), 61–72.
Bange, H.W., Sim, C.H., Bastian, D., Kallert, J., Kock, A., Mujahid, A., Müller, M., Nitrous oxide (N2O) and methane (CH4) in rivers and estuaries of northwestern Borneo. Biogeosciences 16 (2019), 4321–4335.
Barbosa, P.M., Melack, J.M., Farjalla, V.F., Amaral, J.H.F., Scofield, V., Forsberg, B.R., Diffusive methane fluxes from Negro, Solimões and Madeira rivers and fringing lakes in the Amazon basin. Limnol. Oceanogr. 61 (2016), S221–S237.
Barbosa, P.M., Melack, J.M., Amaral, J.H.F., MacIntyre, S., Kasper, D., Cortés, A., Farjalla, V.F., Forsberg, B.R., Dissolved CH4 concentrations and fluxes to the atmosphere from a tropical floodplain lake. Biogeochemistry 148 (2020), 129–151.
Barros, N., Cole, J.J., Tranvik, L.J., Prairie, Y.T., Bastviken, D., Huszar, V.L.M., del Giorgio, P., Roland, F., Carbon emission from hydroelectric reservoirs linked to reservoir age and latitude. Nat. Geosci. 4 (2011), 593–596.
Bastviken, D., Tranvik, L.J., Downing, J.A., Crill, P.M., Enrich-Prast, A., 2011. Freshwater methane emissions offset the continental carbon sink. Science 331, 50–50.
Beadle, L.C., Scientific results of the Cambridge Expedition to the East African Lakes 1930–31. 4. The waters of some East African lakes in relation to their fauna and flora. J. Linn. Sot. Zool. 38 (1932), 157–211.
Beadle, L.C., Prolonged stratification and deoxygenation in tropical lakes. I. Crater lake Nkugute, Uganda, compared with Lakes Bunyoni and Edward. Limnol. Oceanogr. 11 (1966), 152–163.
Beaulieu, J.J., McManus, M.G., Nietch, C.T., Estimates of reservoir methane emissions based on a spatially balanced probabilistic-survey. Limnol. Oceanogr. 61 (2016), S27–S40.
Begum, M.S., Bogard, M.J., Butman, D.E., Chea, E., Kumar, S., Lu, X., Nayna, O.K., Ran, L., Richey, J.E., Tareq, S.M., Xuan, D.T., Yu, R., Park, J.-H., Localized pollution impacts on greenhouse gas dynamics in three anthropogenically modified Asian river systems. J. Geophys. Res. Biogeosciences, 126, 2021, 10.1029/2020JG006124 e2020JG006124.
Beuning, K.R.M., Russell, J.M., Vegetation and sedimentation in the Lake Edward Basin, Uganda-Congo during the late Pleistocene and early Holocene. J. Paleolimnol. 32 (2004), 1–18.
Bižić, M., Klintzsch, T., Ionescu, D., Hindiyeh, M.Y., Günthel, M., Muro-Pastor, A.M., Eckert, W., Urich, T., Keppler, F., Grossart, H.-P., Aquatic and terrestrial cyanobacteria produce methane. Sci. Adv. 6:eaax5343 (2021), 1–9.
Borges, A.V., Abril, G., Delille, B., Descy, J.-P., Darchambeau, F., Diffusive methane emissions to the atmosphere from Lake Kivu (Eastern Africa). J. Geophys. Res., 116, 2011, G03032, 10.1029/2011JG001673.
Borges, A.V., Morana, C., Bouillon, S., Servais, P., Descy, J.-P., Darchambeau, F., Carbon cycling of Lake Kivu (East Africa): net autotrophy in the epilimnion and emission of CO2 to the atmosphere sustained by geogenic inputs. PlosOne, 9, 2014, e109500.
Borges, A.V., Abril, G., Darchambeau, F., Teodoru, C.R., Deborde, J., Vidal, L.O., Lambert, T., Bouillon, S., Divergent biophysical controls of aquatic CO2 and CH4 in the World's two largest rivers. Sci. Rep., 5, 2015, 15614, 10.1038/srep15614.
Borges, A.V., Darchambeau, F., Lambert, T., Morana, C., Allen, G.H., Tambwe, E., Toengaho Sembaito, A., Mambo, T., Nlandu Wabakhangazi, J., Descy, J.-P., Teodoru, C.R., Bouillon, S., Variations in dissolved greenhouse gases (CO2, CH4, N2O) in the Congo River network overwhelmingly driven by fluvial-wetland connectivity. Biogeosciences 16 (2019), 3801–3834.
Borges, A.V., Deirmendjian, L., Bouillon, S., Okello, W., Lambert, T., Roland, F.A.E., Razanamahandry, V.F., Voarintsoa, N.R.G., Darchambeau, F., Kimirei, I.A., Descy, J.-P., Allen, G.H., Morana, C., Greenhouse gas emissions from African lakes are no longer a blind spot. Sci. Adv. 8:eabi8716 (2022), 1–17.
Borges, A.V., Morana, C., Okello, W., Bouillon, S., Biogeochemical data from the HIPE project in Lakes Edward and George (East African Rift), Zenodo, version 1, 2022b, 10.5281/zenodo.7263328.
Call, M., Sanders, C.J., Enrich-Prast, A., Sanders, L., Marotta, H., Santos, I.R., Maher, D.T., Radon-traced pore-water as a potential source of CO2 and CH4 to receding black and clear water environments in the Amazon Basin. Limnol. Oceanogr. Lett., 3(375–383), 2018, 2018.
Codispoti, L.A., Christensen, J.P., Nitirification, denitrification and nitroux oxide cycling in the Eastern tropical South Pacific Ocean. Mar. Chem. 16 (1985), 277–300.
Cole, J.J., Caraco, N.F., Kling, G.W., Kratz, T.K., Carbon dioxide supersaturation in the surface waters of lakes. Science 265 (1994), 1568–1570.
Damas, H., 1937. Recherches hydrobiologiques dans les lacs Kivu, Edouard, et Ndalaga. Explor. Part Natl. Albert, Mission H. Damas (1935-36), Fast. I., 128 p. Inst. Parts Natl. Congo Belge.
de Wilde, H.P.J., de Bie, M.J.M., Nitrous oxide in the Schelde estuary: production by nitrification and emission to the atmosphere. Mar. Chem. 69 (2000), 203–216.
del Giorgio, P.A., Peters, R.H., Patterns in planktonic P: R ratios in lakes: Influence of lake trophy and dissolved organic carbon. Limnol. Oceanogr. 39 (1994), 772–787.
DelSontro, T., del Giorgio, P.A., Prairie, Y.T., No longer a paradox: the interaction between physical transport and biological processes explains the spatial distribution of surface water methane within and across lakes. Ecosystems 21 (2018), 1073–1087.
Denfeld, B.A., Wallin, M.B., Sahlée, E., Sobek, S., Kokic, J., Chmiel, H.E., Weyhenmeyer, G.A., Temporal and spatial carbon dioxide concentration patterns in a small boreal lake in relation to ice-cover dynamics, Boreal Envi. Res. 20 (2015), 679–692.
Descy, J.-P., Hardy, M.-A., Sténuite, S., Pirlot, S., Leporcq, B., Kimirei, I., Sekadende, B., Mwaitega, S.R., Sinyenza, D., Phytoplankton pigments and community composition in Lake Tanganyika. Freshw. Biol. 50 (2005), 668–684.
Desrosiers, K., DelSontro, T., del Giorgio, P.A., Disproportionate contribution of vegetated habitats to the CH4 and CO2 budgets of a boreal lake. Ecosystems, 2021, 10.1007/s10021-021-00730-9.
Duvert, C., Bossa, M., Tyler, K.J., Wynn, J.G., Munksgaard, N.C., Bird, M.I., Setterfield, S.A., Hutley, L.B., Groundwater-derived DIC and carbonate buffering enhance fluvial CO2 evasion in two Australian tropical rivers. J. Geophys. Res. 124 (2019), 312–327.
Frankignoulle, M., Borges, A., Biondo, R., A new design of equilibrator to monitor carbon dioxide in highly dynamic and turbid environments. Water Res. 35 (2001), 1344–1347.
Ganf, G.G., Viner, A.B., Ecological stability in a shallow equatorial lake (Lake George, Uganda). Proc. Roy. Soc. B 184 (1973), 321–346.
Geeraert, N., Omengo, F.O., Borges, A.V., Govers, G., Bouillon, S., Shifts in the carbon dynamics in a tropical lowland river system (Tana River, Kenya) during flooded and non-flooded conditions. Biogeochemistry 132 (2017), 141–163.
Greenwood, P.H., Lake George, Uganda. Philos. Trans. R. Soc. London Series B, Biol. Sci. 274 (1976), 375–391.
Huttunen, J.T., Alm, J., Liikanen, A., Juutinen, S., Larmola, T., Hammar, T., Silvola, J., Martikainen, P.J., Fluxes of methane, carbon dioxide and nitrous oxide in boreal lakes and potential anthropogenic effects on the aquatic greenhouse gas emissions. Chemosphere 52 (2003), 609–621.
Karlsson, J., Giesler, R., Persson, J., Lundin, E., High emission of carbon dioxide and methane during ice thaw in high latitude lakes. Geophys. Res. Lett. 40 (2013), 1123–1127.
Kling, G.W., Comparative transparency, depth of mixing, and stability of stratification in lakes of Cameroon, West Africa. Limnol. Oceanogr. 33 (1988), 27–40.
Kling, G.W., Clark, M.A., Wagner, G.N., Compton, H.R., Humphrey, A.M., Devine, J.D., Evans, W.C., Lockwood, J.P., Tuttle, M.L., Koenigsberg, E.J., The 1986 Lake Nyos gas disaster in Cameroon, West Africa. Sience 236 (1987), 169–175.
Kortelainen, P., Larmola, T., Rantakari, M., Juutinen, S., Alm, J., Martikainen, P.J., Lakes as nitrous oxide sources in the boreal landscape. Glob. Change Biol. 26 (2020), 1432–1445.
Lauerwald, R., Laruelle, G.G., Hartmann, J., Ciais, P., Regnier, P.A.G., Spatial patterns in CO2 evasion from the global river network. Global Biogeochem. Cycles 29 (2015), 534–554.
Lewis, W.M. Jr., A revised classification of lakes based on mixing. Can. J. Fish. Aquat. Sci. 40 (1983), 1779–1787.
Lewis, W.M. Jr., Causes for the high frequency of nitrogen limitation in tropical lakes. Verh. Internat. Verein. Limnol. 28 (2002), 210–213.
Liao, R., Miao, Y., Li, J., Li, Y., Wang, Z., Du, J., Li, Y., Li, A., Shen, H., Temperature dependence of denitrification microbial communities and functional genes in an expanded granular sludge bed reactor treating nitrate-rich wastewater. RSC Adv. 8 (2018), 42087–42094.
Liu, S., Butman, D.E., Raymond, P.A., Evaluating CO2 calculation error from organic alkalinity and pH measurement error in low ionic strength freshwaters. Limnol. Oceanogr. Methods 18 (2020), 606–622.
Liu, S., Kuhn, C., Amatulli, G., Aho, K., Butman, D.E., Allen, G.H., Ling, P., Pan, M., Yamazaki, D., Brinkerhoff, C., Gleason, C., Xia, X., Raymond, P.A., 2022. The importance of hydrology in routing terrestrial carbon to the atmosphere via global streams and rivers. Proc. Natl. Acad. Sci. USA 119, e2106322119.
MacIntyre, S., Climatic variability, mixing dynamics, and ecological consequences in the African Great Lakes. Goldman, C.R., Kumagai, M., Robarts, R.D., (eds.) Climatic Change and Global Warming of Inland Waters: Impacts and Mitigation for Ecosystems and Societies, 2013, Wiley, 311–336.
MacIntyre, S., Romero, J.R., Silsbe, G.M., Emery, B.M., Stratification and horizontal exchange in Lake Victoria, East Africa. Limnol. Oceanogr. 59 (2014), 1805–1838.
Marotta, H., Duarte, C.M., Sobek, S., Enrich-Prast, A., Large CO2 disequilibria in tropical lakes. Global Biogeochem. Cycles, 23, 2009, GB4022, 10.1029/2008GB003434.
Marra, J., Analysis of diel variability in chlorophyll fluo-rescence. J. Mar. Res. 55 (1997), 767–784.
McClain, M.E., Boyer, E.W., Dent, C.L., Gergel, S.E., Grimm, N.B., Groffman, P.M., Hart, S.C., Harvey, J.W., Johnston, C.A., Mayorga, E., McDowell, W.H., Pinay, G., Biogeochemical hot spots and hot moments at the interface of terrestrial and aquatic ecosystems. Ecosystems 6 (2003), 301–312.
Melack, J.M., Hess, L.L., Gastil, M., Forsberg, B.R., Hamilton, S.K., Lima, I.B.T., Novo, E.M.L.M., Regionalization of methane emissions in the Amazon Basin with microwave remote sensing. Global Change Biol. 10 (2004), 530–544.
Mendonça, R., Müller, R.A., Clow, D., Verpoorter, C., Raymond, P., Tranvik, L.J., Sobek, S., Organic carbon burial in global lakes and reservoirs. Nat. Commun. 8:1694 (2017), 1–7.
Mendoza-Pascual, M.U., Itoh, M., Aguilar, J.I., Padilla, K.S.A.R., Papa, R.D.S., Okuda, N., Controlling factors of methane dynamics in tropical lakes of different depths. J. Geophys. Res. Biogeosci., 126, 2021, 10.1029/2020JG005828 e2020JG005828.
Mengis, M., Gächter, R., Wehrli, B., Sources and sinks of nitrous oxide (N2O) in deep lakes. Biogeochemistry 38 (1997), 281–301.
Morana, C., Borges, A.V., Roland, F.A.E., Darchambeau, F., Descy, J.-P., Bouillon, S., Methanotrophy within the water column of a large meromictic tropical lake (Lake Kivu, East Africa). Biogeosciences 12 (2015), 2077–2088.
Morana, C., Bouillon, S., Nolla-Ardèvol, V., Roland, F.A.E., Okello, W., Descy, J.-P., Nankabirwa, A., Nabafu, E., Springael, D., Borges, A.V., Methane paradox in tropical lakes?. Sedimentary fluxes rather than pelagic production in oxic conditions sustain methanotrophy and emissions to the atmosphere. Biogeosciences 17 (2020), 5209–5221.
Morana, C., Borges, A.V., Deirmendjian, L., Okello, W., Sarmento, H., Descy, J.-P., Kimirei, I.A., Bouillon, S., Prevalence of autotrophy in non-humic African lakes. Ecosystems, 2022, 10.1007/s10021-022-00783-4.
Myrstener, M., Jonsson, A., Bergström, A.-K., The effects of temperature and resource availability on denitrification and relative N2O production in boreal lake sediments. J. Environ. Sci. 47 (2016), 82–90.
Ollivier, Q.R., Maher, D.T., Pitfield, C., Macreadie, P.E., Net drawdown of greenhouse gases (CO2, CH4 and N2O) by a temperate Australian seagrass meadow. Estuaries Coasts 45 (2022), 2026–2039.
Palacin-Lizarbe, C., Camarero, L., Catalan, J., Denitrification temperature dependence in remote, cold, and N-poor lake sediments. Water Resour. Res. 54 (2018), 1161–1173.
Panneer Selvam, B., Natchimuthu, S., Arunachalam, L., Bastviken, D., Methane and carbon dioxide emissions from inland waters in India - implications for large scale greenhouse gas balances. Glob. Chang. Biol. 20 (2014), 3397–3407.
Raymond, P.A., 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., Global carbon dioxide emissions from inland waters. Nature 503 (2013), 355–359.
Reading, M.J., Maher, D.T., Santos, I.R., Jeffrey, L.C., Cyronak, T.J., McMahon, A., Tait, D.R., 2021. Spatial distribution of CO2, CH4, and N2O in the Great Barrier Reef revealed through high resolution sampling and isotopic analysis. Geophys. Res. Lett. 48, e2021GL092534; 10.1029/2021GL092534.
Richey, J.E., Devol, A.H., Wofy, S.C., Victoria, R., Riberio, M.N.G., Biogenic gases and the oxidation and reduction of carbon in Amazon River and floodplain waters. Limnol. Oceanogr. 33 (1998), 551–561.
Richey, J.E., Melack, J.M., Aufdenkampe, A.K., Ballester, V.M., Hess, L., Outgassing from Amazonian rivers and wetlands as a large tropical source of atmospheric CO2. Nature 416 (2002), 617–620.
Rosentreter, J.A., Borges, A.V., Deemer, B.R., Holgerson, M.A., Liu, S., Song, C., Melack, J., Raymond, P.A., Duarte, C.M., Allen, G.H., Olefeldt, D., Poulter, B., Battin, T.I., Eyre, B.D., Half of global methane emissions come from highly variable aquatic ecosystem sources. Nat. Geosci. 14 (2021), 225–230.
Russell, J.M., Johnson, T.C., The water balance and stable isotope hydrology of Lake Edward, Uganda-Congo. J. Great Lakes Res. 32 (2006), 77–90.
Sand-Jensen, K., Staehr, P.A., Scaling of pelagic metabolism to size, trophy and forest cover in small Danish lakes. Ecosystems 10 (2007), 127–141.
Schilder, J., Bastviken, D., van Hardenbroek, M., Kankaala, P., Rinta, P., Stotter, T., Heiri, O., Spatial heterogeneity and lake morphology affect diffusive greenhouse gas emission estimates of lakes. Geophys. Res. Lett. 40 (2013), 5752–5756.
Simpson, J.H., The shelf-sea fronts: Implications of their existence and behaviour. Philos. Trans. R. Soc. Lond. 302 (1981), 531–546.
Simpson, J.H., Lucas, N.S., Powell, B., Maberly, S.C., Dissipation and mixing during the onset of stratification in a temperate lake, Windermere. Limnol. Oceanogr. 60 (2014), 29–41.
Sjöberg, Y., Dessirier, B., Ghajarnia, N., Jaramillo, F., Jarsjö, J., Panahi, D.M., Xu, D., Zou, L., Manzoni, S., Scaling relations reveal global and regional differences in morphometry of reservoirs and natural lakes. Sci. Total Environ., 822, 2022, 153510.
Snover, A.K., Quay, P.D., Hydrogen and carbon kinetic isotope effects during soil uptake of atmospheric methane. Global Biogeochem. Cycles 14 (2000), 25–39.
Sobek, S., Tranvik, L.J., Cole, J.J., 2005. Temperature independence of carbon dioxide supersaturation in global lakes. Global Biogeochem. Cycles 19, GB2003, 10.1029/2004GB002264.
Soued, C., del Giorgio, P.A., Maranger, R., Variability in N2O fluxes across boreal aquatic networks. Nat. Geosci. 9 (2015), 116–120.
Standing committee of Analysts, 1981. Ammonia in waters. Methods for the examination of waters and associated materials.
Stoyneva-Gaertner, M., Morana, C., Borges, A.V., Okello, W., Bouillon, S., Deirmendjian, L., Lambert, T., Roland, F., Nankabirwa, A., Nabafu, E., Darchambeau, F., Descy, J.-P., Diversity and ecology of phytoplankton in Lake Edward (East Africa): present status and long-term changes. J. Great Lakes Res. 46 (2020), 741–751.
Tait, D.R., Maher, D.T., Wong, W.W., Santos, I.R., Sadat-Noori, M., Holloway, C., Cook, P.L.M., Greenhouse gas dynamics in a salt-wedge estuary revealed by high resolution cavity ring-down spectroscopy observations. Environ. Sci. Technol. 51 (2017), 13771–13778.
Teodoru, C.R., Nyoni, F.C., Borges, A.V., Darachambeau, F., Nyambe, I., Bouillon, S., Spatial variability and temporal dynamics of greenhouse gas (CO2, CH4, N2O) concentrations and fluxes along the Zambezi River mainstem and major tributaries. Biogeosciences 12 (2015), 2431–2453.
Verbeke, J., 1957. Recherches écologiques sur la faune des grands lacs de l'est du Congo belge. Bulletin de l'Institut royal des Sciences naturelles de Belgique: Résultats scientifiques de l'exploration hydrobiologique (1952-1954) des lacs Kivu, Edouard et Albert.
Viner, A.B., Smith, I.R., Geographical, historical and physical aspects of Lake George. Proc. Roy. Soc. B 184 (1973), 235–270.
Webb, J.R., Maher, D.T., Santos, I.R., 2016. Automated, in situ measurements of dissolved CO2, CH4, and δ13C values using cavity enhanced laser absorption spectrometry: Comparing response times of air-water equilibrators. Limnol. Oceanogr.: Methods 14, 323-337.
Weiss, R.F., Determinations of carbon dioxide and methane by dual catalyst flame ionization chromatography and nitrous oxide by electron capture chromatography. J. Chromatogr. Sci. 19 (1981), 611–616.
Weiss, R.F., Price, B.A., Nitrous oxide solubility in water and seawater. Mar. Chem. 8 (1980), 347–359.
Wells, N.S., Chen, J.-J., Maher, D.T., Huang, P., Erler, D.V., Hipsey, M., Eyre, B.D., Changing sediment and surface water processes increase CH4 emissions from human-impacted estuaries. Geochim. Cosmochim. Acta 280 (2020), 130–147.
Wit, F., Müller, D., Baum, A., Warneke, T., Pranowo, W.S., Müller, M., The impact of disturbed peatlands on river outgassing in Southeast Asia. Nat. Commun. 6 (2015), 1–9.
