Unpublished conference/Abstract (Scientific congresses and symposiums)
Spatial variability and temporal dynamics of greenhouse gas (CO2, CH4, N2O) concentrations and fluxes along the Zambezi River mainstem and major tributaries
Nyoni, Frank C.; Nyambe, Imasiku Anayawa; Teodoru, Crístian R. et al.
20155th Zambia Water Forum and Exhibition (ZAWAFE)
 

Files


Full Text
5th ZAWAFE Presentation_2015 - Frank C. Nyoni.pdf
Publisher postprint (6.93 MB)
Download

All documents in ORBi are protected by a user license.

Send to



Details



Abstract :
[en] Spanning over 3000 km in length and with a catchment of approximately 1.4 million km2, the Zambezi River is the fourth largest river in Africa and the largest flowing into the Indian Ocean from the African continent. As part of a broader study on the riverine biogeochemistry in the Zambezi River basin, we present data on greenhouse gas (GHG, carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O) concentrations and fluxes collected along the Zambezi River, reservoirs and several of its tributaries during 2012 and 2013 and over two climatic seasons (dry and wet) to constrain the inter-annual variability, seasonality and spatial heterogeneity along the aquatic continuum. All GHGs concentrations showed high spatial variability (coefficient of variation: 1.01 for CO2, 2.65 for CH4 and 0.21 for N2O). Overall, there was no unidirectional pattern along the river stretch (i.e. decrease or increase towards the ocean), as the spatial heterogeneity of GHGs appeared to be determined mainly by the connectivity with floodplains and wetlands, and the presence of man-made structures (reservoirs) and natural barriers (waterfalls, rapids). Highest CO2 and CH4 concentrations in the mainstream river were found downstream of extensive floodplains/wetlands. Undersaturated CO2 conditions, in contrast, were characteristic for the surface waters of the two large reservoirs along the Zambezi mainstem. N2O concentrations showed the opposite pattern, being lowest downstream of floodplains and highest in reservoirs. Among tributaries, highest concentrations of both CO2 and CH4 were measured in the Shire River whereas low values were characteristic for more turbid systems such as the Luangwa and Mazoe rivers. The interannual variability in the Zambezi River was relatively large for both CO2 and CH4, and significantly higher concentrations (up to two fold) were measured during wet seasons compared to the dry season. Interannual variability of N2O was less pronounced but generally higher values were found during the dry season. Overall, both concentrations and fluxes of CO2 and CH4 were well below the median/average values reported for tropical rivers, streams and reservoirs. A first-order mass balance suggests that carbon (C) transport to the ocean represents the major component (59 %) of the budget (largely in the form of DIC), while only 38% of total C yield is annually emitted into the atmosphere, mostly as CO2 (98 %), and 3% is removed by sedimentation in reservoirs.
Research center :
FOCUS - Freshwater and OCeanic science Unit of reSearch - ULiège
Disciplines :
Aquatic sciences & oceanology
Author, co-author :
Nyoni, Frank C.
Nyambe, Imasiku Anayawa
Teodoru, Crístian R.
Borges, Alberto  ;  Université de Liège > Département d'astrophys., géophysique et océanographie (AGO) > Chemical Oceanography Unit (AGO)
Darchambeau, François ;  Université de Liège > Département d'astrophys., géophysique et océanographie (AGO) > Chemical Oceanography Unit (AGO)
Bouillon, Steven
Language :
English
Title :
Spatial variability and temporal dynamics of greenhouse gas (CO2, CH4, N2O) concentrations and fluxes along the Zambezi River mainstem and major tributaries
Publication date :
02 November 2015
Event name :
5th Zambia Water Forum and Exhibition (ZAWAFE)
Event place :
Lusaka, Zambia
Event date :
2-3 November 2015
Available on ORBi :
since 09 June 2016

Statistics


Number of views
95 (9 by ULiège)
Number of downloads
39 (1 by ULiège)

Bibliography


Similar publications



Contact ORBi