Coynel A. auteur aut IRD Seyler Patrick auteur aut IRD Etcheber H. auteur aut IRD Meybeck M. auteur aut IRD Orange Didier auteur aut IRD text journalArticle eng text/pdf reformatted digital access [1] The Congo ( Zaire) River, the world's second largest river in terms both of water discharges and of drainage area after the Amazon River, has remained to date in a near-pristine state. For a period between 2 and 6 years, the mainstream near the river mouth (Brazzaville/Kinshasa station) and some of the major and minor tributaries ( the Oubangui, Mpoko, and Ngoko-Sangha) were monitored every month for total suspended sediment (TSS), particulate organic carbon (POC), and dissolved organic carbon (DOC). In this large but relatively flat equatorial basin, TSS levels are very low and organic carbon is essentially exported as DOC: from 74% of TOC for the tributaries flowing in savannah regions and 86% for those flowing in the rain forest. The seasonal patterns of TSS, POC, and DOC show clockwise hysteresis in relation to river discharges, with maximum levels recorded 2 to 4 months before peak flows. At the Kinshasa/ Brazzaville station, the DOC distribution is largely influenced by the input from the tributaries draining the large marshy forest area located in the center of the basin. There is a marked difference between specific fluxes, threefold higher in the forest basins than in the savannah basins. The computation of inputs to the Atlantic Ocean demonstrates that the Congo is responsible for 14.4 x 10(6) t/yr of TOC of which 12.4 x 10(6) t/yr is DOC and 2 x 10(6) t/yr is POC. The three biggest tropical rivers ( the Amazon, the Congo, and the Orinoco), with only 10% of the exoreic world area drained to world oceans, contribute similar to 4% of its TSS inputs but 15 - 18% of its organic carbon inputs. These proportions may double when considering only world rivers discharging into the open ocean. specialized CONGO ZAIRE 064 062 19 4 17 2005 0886-6236 https://www.documentation.ird.fr/hor/fdi:010084911 10.1029/2004GB002335 0886-6236 [F B010084911] https://www.documentation.ird.fr/hor/fdi:010084911 https://horizon.documentation.ird.fr/exl-doc/pleins_textes/2022-07/010084911.pdf IRD - Base Horizon / Pleins textes 2006-03-30 2022-07-27 fdi:010084911 fre