Amouroux, D., Roberts, G., Rapsomanikis, S., and Andreae, M. O.: Biogenic
Gas (CH
4, N
2O, DMS) Emission to the Atmosphere from Near-shore and Shelf Waters of the North-western Black Sea, Estuar. Coast. Shelf S., 54, 575–587, https://doi.org/10.1006/ecss.2000.0666, 2002.
Aufdenkampe, A. K., Mayorga, E., Raymond, P. A., Melack, J. M., Doney, S.
C., Alin, S. R., Aalto, R. E., and Yoo, K.: Riverine coupling of
biogeochemical cycles between land, oceans, and atmosphere, Front.
Ecol. Environ., 9, 53–60, https://doi.org/10.1890/100014, 2011.
Badr, E.-S. A.: Spatio-temporal variability of dissolved organic nitrogen
(DON), carbon (DOC), and nutrients in the Nile River, Egypt, Environ.
Monit. Assess., 188, 580, https://doi.org/10.1007/s10661-016-5588-5, 2016.
Begy, R. C., Simon, H., Kelemen, S., and Preoteasa, L.: Investigation of
sedimentation rates and sediment dynamics in Danube Delta lake system
(Romania) by
210Pb dating method, Journal of Environmental Radioactivity, 192, 95–104, https://doi.org/10.1016/j.jenvrad.2018.06.010,
2018.
Bianchi, T. S., Filley, T., Dria, K., and Hatcher, P. G.: Temporal
variability in sources of dissolved organic carbon in the lower Mississippi
river, Geochim. Cosmochim. Ac., 68, 959–967, https://doi.org/10.1016/j.gca.2003.07.011, 2004.
Bianchi, T. S., Wysocki, L. A., Stewart, M., Filley, T. R., and McKee, B.
A.: Temporal variability in terrestrially-derived sources of particulate
organic carbon in the lower Mississippi River and its upper tributaries,
Geochim. Cosmochim. Ac., 71, 4425–4437, https://doi.org/10.1016/j.gca.2007.07.011, 2007.
Borges, A. V.: Do we have enough pieces of the jigsaw to integrate CO2
fluxes in the coastal ocean?, Estuaries, 28, 3–27, https://doi.org/10.1007/BF02732750, 2005.
Borges, A. V. and Abril, G.: Carbon Dioxide and Methane Dynamics in
Estuaries, in: Treatise on Estuarine and Coastal Science, edited by:
Wolanski, E. and McLusky, D., Academic Press, Waltham, 119–161, 2011.
Borges, A. V., Delille, B., and Frankignoulle, M.: Budgeting sinks and
sources of CO
2 in the coastal ocean: Diversity of ecosystems counts,
Geophys. Res. Lett., 32, L14601, https://doi.org/10.1029/2005gl023053, 2005.
Borges, A. V., Abril, G., Darchambeau, F., Teodoru, C. R., Deborde, J.,
Vidal, L. O., Lambert, T., and Bouillon, S.: Divergent biophysical controls
of aquatic CO
2 and CH
4 in the World's two largest rivers, Sci.
Rep.-UK, 5, 15614, https://doi.org/10.1038/srep15614, 2015.
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., and Bouillon, S.: Variations in dissolved greenhouse gases (CO
2, CH
4, N
2O) in the Congo River network overwhelmingly driven by fluvial-wetland connectivity, Biogeosciences, 16, 3801–3834, https://doi.org/10.5194/bg-16-3801-2019, 2019.
Brix, H., Sorrell, B. K., and Lorenzen, B.: Are Phragmites-dominated
wetlands a net source or net sink of greenhouse gases?, Aquat. Bot., 69,
313–324, https://doi.org/10.1016/S0304-3770(01)00145-0, 2001.
BSC: State of Environment of the Black Sea (2001-2006/7), Istanbul, Turkey,
448 pp., 2008.
Cai, W.-J.: Estuarine and Coastal Ocean Carbon Paradox: CO
2 Sinks or Sites
of Terrestrial Carbon Incineration?, Annu. Rev. Mar. Sci., 3,
123–145, https://doi.org/10.1146/annurev-marine-120709-142723, 2011.
Cai, W. J., Arthur Chen, C. T., and Borges, A.: Carbon dioxide dynamics and
fluxes in coastal waters influenced by river plumes, in: Biogeochemical
Dynamics at Major River-Coastal Interfaces: Linkages with Global Change,
edited by: Allison, M. A., Bianchi, T. S., and Cai, W.-J., Cambridge
University Press, Cambridge, 155–173, 2013.
Cole, J. J., Prairie, Y. T., Caraco, N. F., McDowell, W. H., Tranvik, L. J.,
Striegl, R. G., Duarte, C. M., Kortelainen, P., Downing, J. A., Middelburg,
J. J., and Melack, J.: Plumbing the global carbon cycle: Integrating inland
waters into the terrestrial carbon budget, Ecosystems, 10, 171–184,
https://doi.org/10.1007/s10021-006-9013-8, 2007.
Coops, H., Hanganu, J., Tudor, M., and Oosterberg, W.: Classification of Danube Delta lakes based on aquatic vegetation and turbidity, Hydrobiologia, 415, 187–191, https://doi.org/10.1023/A:1003856927865, 1999.
Coops, H., Buijse, L. L., Buijse, A. D. T., Constantinescu, A., Covaliov,
S., Hanganu, J., Ibelings, B. W., Menting, G., Navodaru, I., and Oosterberg,
W.: Trophic gradients in a large-river Delta: ecological structure
determined by connectivity gradients in the Danube Delta (Romania), Riv.
Res. Appl., 24, 698–709, https://doi.org/10.1002/rra.1136, 2008.
Coynel, A., Seyler, P., Etcheber, H., Meybeck, M., and Orange, D.: Spatial
and seasonal dynamics of total suspended sediment and organic carbon species
in the Congo River, Glob. Biogeochem. Cy., 19, GB4019, https://doi.org/10.1029/2004GB002335, 2005.
D'Amario, S. C. and Xenopoulos, M. A.: Linking dissolved carbon dioxide to
dissolved organic matter quality in streams, Biogeochemistry, 126, 99–114,
https://doi.org/10.1007/s10533-015-0143-y, 2015.
Dai, A., Qian, T., Trenberth, K. E., and Milliman, J. D.: Changes in
Continental Freshwater Discharge from 1948 to 2004, J. Climate, 22,
2773–2792, https://doi.org/10.1175/2008jcli2592.1, 2009.
Dai, M., Yin, Z., Meng, F., Liu, Q., and Cai, W.-J.: Spatial distribution of
riverine DOC inputs to the ocean: an updated global synthesis, Curr.
Opin. Env. Sust., 4, 170–178, https://doi.org/10.1016/j.cosust.2012.03.003, 2012.
Danube Commission: Hydrologisches Nachschlagewerk der Donau 1921–2010,
Donaukommission Budapest, 2018.
DANUBS: Nutrient Management in the Danube Basin and its Impact on the Black
Sea, Vienna University of Technology, 2005.
De Muth, J. E.: Basic Statistics and Pharmaceutical Statistical
Applications, 3rd Edition, Pharmacy Education Series, Hoboken Chapman and
Hall/CRC, Boca Raton, USA, 2014.
DeLaune, R. D., White, J. R., Elsey-Quirk, T., Roberts, H. H., and Wang, D.
Q.: Differences in long-term vs short-term carbon and nitrogen sequestration
in a coastal river delta wetland: Implications for global budgets, Org.
Geochem., 123, 67–73, https://doi.org/10.1016/j.orggeochem.2018.06.007, 2018.
Drake, T. W., Raymond, P. A., and Spencer, R. G. M.: Terrestrial carbon
inputs to inland waters: A current synthesis of estimates and uncertainty,
Limnol. Oceanogr. Lett., 3, 132–142, https://doi.org/10.1002/lol2.10055, 2018.
Druffel, E. R. M., Bauer, J. E., and Griffin, S.: Input of particulate
organic and dissolved inorganic carbon from the Amazon to the Atlantic
Ocean, Geochem. Geophy. Geosy., 6, Q03009, https://doi.org/10.1029/2004gc000842, 2005.
Dubois, K. D., Lee, D., and Veizer, J.: Isotopic constraints on alkalinity,
dissolved organic carbon, and atmospheric carbon dioxide fluxes in the
Mississippi River, J. Geophys. Res.-Biogeosci., 115, G02018, https://doi.org/10.1029/2009JG001102, 2010.
Durisch-Kaiser, E., Pavel, A., Doberer, A., Reutimann, J., Balan, S., Sobek,
S., Radan, S., and Wehrli, B.: Nutrient retention, total N and P export and
greenhouse gas emission from the Danub Delta lakes, GeoEcoMarina, 14, 81–90, 2008.
Dürr, H. H., Laruelle, G. G., van Kempen, C. M., Slomp, C. P., Meybeck,
M., and Middelkoop, H.: Worldwide Typology of Nearshore Coastal Systems:
Defining the Estuarine Filter of River Inputs to the Oceans, Estuar.
Coast., 34, 441–458, https://doi.org/10.1007/s12237-011-9381-y, 2011.
Feodorov: eDelta: available at:
https://edelta.ro/isaccea-365, last access: 31 December 2017.
Gaillardet, J., Dupré, B., Louvat, P., and Allègre, C. J.: Global
silicate weathering and CO2 consumption rates deduced from the chemistry of
large rivers, Chem. Geol., 159, 3–30, https://doi.org/10.1016/S0009-2541(99)00031-5, 1999.
Galloway, W. E.:
Process framework for describing the morphologic and stratigraphic evolution of deltaic depositional systems
edited by: Broussard, M. L., Deltas, Models for Exploration, Houston Geol. Soc., 87–98, 197.
Grasset, C., Abril, G., Guillard, L., Delolme, C., and Bornette, G.: Carbon
emission along a eutrophication gradient in temperate riverine wetlands:
effect of primary productivity and plant community composition, Freshwater
Biol., 61, 1405–1420, https://doi.org/10.1111/fwb.12780, 2016.
Greenway, M. and Woolley, A.: Constructed wetlands in Queensland:
Performance efficiency and nutrient bioaccumulation, Ecol. Eng.,
12, 39–55, https://doi.org/10.1016/S0925-8574(98)00053-6, 1999.
Hastie, A., Lauerwald, R., Ciais, P., and Regnier, P.: Aquatic carbon fluxes
dampen the overall variation of net ecosystem productivity in the Amazon
basin: An analysis of the interannual variability in the boundless carbon
cycle, Glob. Change Biol., 25, 2094–2111, https://doi.org/10.1111/gcb.14620, 2019.
Holgerson, M. A. and Raymond, P. A.: Large contribution to inland water CO
2 and CH
4 emissions from very small ponds, Nat. Geosci., 9, 222–226, https://doi.org/10.1038/ngeo2654, 2016.
Hope, D., Billett, M. F., and Cresser, M. S.: A review of the export of
carbon in river water: Fluxes and processes, Environ. Pollut., 84,
301–324, https://doi.org/10.1016/0269-7491(94)90142-2, 1994.
ICPDR: Danube River Basin Water Quality Database, available at:
http://www.icpdr.org/wq-db/ (last access: 29 October 2019), 2018.
INHGA: Romanian National Institute of Hydrology and Water Management, available at:
http://www.inhga.ro/diagnoza_si_prognoza_dunare, last access: 31 December 2017.
IPCC: The physical science basis. Contribution of working group I to the
fourth assessment report of the Intergovernmental Panel on Climate Change,
Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA, 2007.
IPCC: Climate Change 2013: The Physical Science Basis. Contribution of
Working Group I to the Fifth Assessment Report of the Intergovernmental
Panel on Climate Change, Cambridge University Press, Cambridge; United
Kingdom and New York, NY; USA, 1535 pp., 2013.
Irimus, I.: The hydrological regime of the Danube in the deltaic sector, in:
Danube Delta: genesis and biodiversity, edited by: Tudorancea, C. and
Tudorancea, M. M., Backhuys Publishers, Leiden, The Netherlands, 53–64,
2006.
Jiang, Z.-P., Cai, W.-J., Lehrter, J., Chen, B., Ouyang, Z., Le, C., Roberts, B. J., Hussain, N., Scaboo, M. K., Zhang, J., and Xu, Y.: Spring net community production and its coupling with the CO2 dynamics in the surface water of the northern Gulf of Mexico, Biogeosciences, 16, 3507–3525, https://doi.org/10.5194/bg-16-3507-2019, 2019.
Kirschbaum, M. U. F., Zeng, G., Ximenes, F., Giltrap, D. L., and Zeldis, J. R.: Towards a more complete quantification of the global carbon cycle, Biogeosciences, 16, 831–846, https://doi.org/10.5194/bg-16-831-2019, 2019.
Laruelle, G. G., Dürr, H. H., Slomp, C. P., and Borges, A. V.:
Evaluation of sinks and sources of CO
2 in the global coastal ocean using a
spatially-explicit typology of estuaries and continental shelves,
Geophys. Res. Lett., 37, L15607, https://doi.org/10.1029/2010gl043691, 2010.
Lauerwald, R., Laruelle, G. G., Hartmann, J., Ciais, P., and Regnier, P. A.
G.: Spatial patterns in CO2 evasion from the global river network, Glob.
Biogeochem. Cy., 29, 534–554, https://doi.org/10.1002/2014GB004941, 2015.
Li, M., Peng, C., Wang, M., Xue, W., Zhang, K., Wang, K., Shi, G., and Zhu,
Q.: The carbon flux of global rivers: A re-evaluation of amount and spatial
patterns, Ecol. Ind., 80, 40–51, https://doi.org/10.1016/j.ecolind.2017.04.049, 2017.
Ludwig, W., Probst, J.-L., and Kempe, S.: Predicting the oceanic input of
organic carbon by continental erosion, Glob. Biogeochem. Cy., 10,
23–41, https://doi.org/10.1029/95gb02925, 1996.
Maier, M.-S., Teodoru, C. R., and Wehrli, B.: Spatio-temporal variations of lateral and atmospheric carbon fluxes from the Danube Delta (dataset), A 2-year dataset of measured concentrations and fluxes, ETH Zurich, available at:
https://doi.org/10.3929/ethz-b-000416925, last access: 27 May 2020.
Mapcruzin.com: available at:
https://mapcruzin.com/free-romania-arcgis-maps-shapefiles.htm, last access: 13 December 2016.
Marchand, D., Prairie, Y. T., and Del Giorgio, P. A.: Linking forest fires
to lake metabolism and carbon dioxide emissions in the boreal region of
Northern Québec, Glob. Change Biol., 15, 2861–2873, https://doi.org/10.1111/j.1365-2486.2009.01979.x, 2009.
Mayorga, E., Aufdenkampe, A. K., Masiello, C. A., Krusche, A. V., Hedges, J.
I., Quay, P. D., Richey, J. E., and Brown, T. A.: Young organic matter as a
source of carbon dioxide outgassing from Amazonian rivers, Nature, 436,
538–541, https://doi.org/10.1038/nature03880, 2005.
Meybeck, M. and Ragu, A.: River discharges to the oceans: an assessment of
suspended solids, major ions and nutrients, UNEP, UN Environmental Programme
Place published Nairobi, 1997.
Mihailescu, N.: Danube delta geology, geomorphology and geochemistry, in:
Danube Delta: Genesis and Biodiversity, edited by: Tudorancea, C. and
Tudorancea, M. M., Backhuys Publishers, Leiden, 9–35, 2006.
Moquet, J. S., Guyot, J. L., Crave, A., Viers, J., Filizola, N., Martinez,
J. M., Oliveira, T. C., Sanchez, L. S., Lagane, C., Casimiro, W. S.,
Noriega, L., and Pombosa, R.: Amazon River dissolved load: temporal dynamics
and annual budget from the Andes to the ocean, Environ. Sci. Pollut. Res. Int., 23, 11405–11429, https://doi.org/10.1007/s11356-015-5503-6, 2016.
Niculescu, S., Lardeux, C., and Hanganu, J.: Alteration and Remediation of
Coastal Wetland Ecosystems in the Danube Delta: A Remote-Sensing Approach,
in: Coastal Wetlands: Alteration and Remediation, edited by: Finkl, C. W.
and Makowski, C., Springer International Publishing, Cham, 513–553, 2017.
Nisbet, E. G., Manning, M. R., Dlugokencky, E. J., Fisher, R. E., Lowry, D., Michel, S. E., Myhre, C. L., Platt, S. M., Allen, G., Bousquet, P., Brownlow, R., Cain, M., France, J. L., Hermansen, O., Hossaini, R., Jones, A. E., Levin, I., Manning, A. C., Myhre, G., Pyle, J. A., Vaughn, B. H., Warwick, N. J., and White, J. W. C.: Very Strong Atmospheric Methane Growth in the 4 Years 2014–2017: Implications for the Paris Agreement, Global Biogeochem. Cy., 33, 318–342, https://doi.org/10.1029/2018gb006009, 2019.
Oosterberg, W., Staras, M., Bogdan, L., Buijse, A. D., Constantinescu, A.,
Coops, H., Hanganu, J., Ibelings, B. W., Menting, G. A. M., and Navodaru,
I.: Ecological gradients in the Danube Delta lakes: present state and
man-induced changes, Institute for Inland Water Management and Waste Water Treatment RIZA, available at:
https://archive-ouverte.unige.ch/unige:26576 (last access: 2 February 2021), 2000.
Pavel, A., Durisch-Kaiser, E., Balan, S., Radan, S., Sobek, S., and Wehrli,
B.: Sources and emission of greenhouse gases in Danube Delta lakes,
Environ. Sci. Pollut. Res., 16, 86–91, https://doi.org/10.1007/s11356-009-0182-9, 2009.
Postma, G.: An analysis of the variation in delta architecture, Terra Nova,
2, 124–130, https://doi.org/10.1111/j.1365-3121.1990.tb00052.x, 1990.
Raymond, P. A., Hartmann, J., Lauerwald, R., Sobek, S., McDonald, C.,
Hoover, M., Butman, D., Striegl, R., Mayorga, E., Humborg, C., Kortelainen,
P., Durr, H., Meybeck, M., Ciais, P., and Guth, P.: Global carbon dioxide
emissions from inland waters, Nature, 503, 355–359, https://doi.org/10.1038/nature12760, 2013.
Richey, J. E., Melack, J. M., Aufdenkampe, A. K., Ballester, V. M., and
Hess, L. L.: Outgassing from Amazonian rivers and wetlands as a large
tropical source of atmospheric CO
2, Nature, 416, 617–620, https://doi.org/10.1038/416617a, 2002.
Sarbu, A.: Aquatic macrophytes, in: Danube Delta: Genesis and Biodiversity,
edited by: Tudorancea, C. and Tudorancea, M. M., Backhuys Publishers,
Leiden, 133–175, 2006.
Sawakuchi, H. O., Bastviken, D., Sawakuchi, A. O., Krusche, A. V.,
Ballester, M. V., and Richey, J. E.: Methane emissions from Amazonian Rivers
and their contribution to the global methane budget, Glob. Change Biol.,
20, 2829–2840, https://doi.org/10.1111/gcb.12646, 2014.
Sawakuchi, H. O., Neu, V., Ward, N. D., Barros, M. D. C., Valerio, A. M.,
Gagne-Maynard, W., Cunha, A. C., Less, D. F. S., Diniz, J. E. M., Brito, D.
C., Krusche, A. V., and Richey, J. E.: Carbon Dioxide Emissions along the
Lower Amazon River, Front. Mar. Sci., 4, 1–12, https://doi.org/10.3389/fmars.2017.00076, 2017.
Soltan, M. and Awadallah, R.: Chemical survey on the River Nile water from
Aswan into the outlet, J. Environ. Sci. Heal. A,
30, 1647–1658, https://doi.org/10.1080/10934529509376293, 1995.
Teodoru, C. R., Nyoni, F. C., Borges, A. V., Darchambeau, F., Nyambe, I., and Bouillon, S.: Dynamics of greenhouse gases (CO
2, CH
4, N
2O) along the Zambezi River and major tributaries, and their importance in the riverine carbon budget, Biogeosciences, 12, 2431–2453, https://doi.org/10.5194/bg-12-2431-2015, 2015.
Tootchi, A., Jost, A., and Ducharne, A.: Multi-source global wetland maps combining surface water imagery and groundwater constraints, Earth Syst. Sci. Data, 11, 189–220, https://doi.org/10.5194/essd-11-189-2019, 2019.
Tranvik, L. J., Downing, J. A., Cotner, J. B., Loiselle, S. A., Striegl, R.
G., Ballatore, T. J., Dillon, P., Finlay, K., Fortino, K., and Knoll, L. B.:
Lakes and reservoirs as regulators of carbon cycling and climate, Limnol. Oceanogr., 54, 2298–2314, https://doi.org/10.4319/lo.2009.54.6_part_2.2298, 2009.
Wanninkhof, R.: Relationship between wind speed and gas exchange over the
ocean, J. Geophys. Res.-Ocean., 97, 7373–7382, https://doi.org/10.1029/92JC00188, 1992.
Ward, N. D., Sawakuchi, H. O., Neu, V., Less, D. F. S., Valerio, A. M.,
Cunha, A. C., Kampel, M., Bianchi, T. S., Krusche, A. V., Richey, J. E., and
Keil, R. G.: Velocity-amplified microbial respiration rates in the lower
Amazon River, Limnol. Oceanogr. Lett., 3, 265–274, https://doi.org/10.1002/lol2.10062, 2018.
Weiss, R. F.: Carbon dioxide in water and seawater: the solubility of a
non-ideal gas, Mar. Chem., 2, 203–215, https://doi.org/10.1016/0304-4203(74)90015-2, 1974.
Zhang, K., Liu, Y., Chen, Q., Luo, H., Zhu, Z., Chen, W., Chen, J., and Mo,
Y.: Effect of submerged plant species on CH4 flux and methanogenic community
dynamics in a full-scale constructed wetland, Ecol. Eng., 115,
96–104, https://doi.org/10.1016/j.ecoleng.2018.02.025, 2018.
Zhou, L., Zhou, G., and Jia, Q.: Annual cycle of CO
2 exchange over a reed
(Phragmites australis) wetland in Northeast China, Aquat. Bot., 91,
91–98, https://doi.org/10.1016/j.aquabot.2009.03.002, 2009.
Zuijdgeest, A., Baumgartner, S., and Wehrli, B.: Hysteresis effects in
organic matter turnover in a tropical floodplain during a flood cycle,
Biogeochemistry, 131, 49–63, https://doi.org/10.1007/s10533-016-0263-z, 2016.
Zurbrügg, R., Wamulume, J., Kamanga, R., Wehrli, B., and Senn, D. B.:
River-floodplain exchange and its effects on the fluvial oxygen regime in a
large tropical river system (Kafue Flats, Zambia), J. Geophys.
Res.-Biogeosci., 117, https://doi.org/10.1029/2011JG001853, 2012.
