Abstract
Total suspended solids (TSS), particulate organic carbon (POC) and particulate nitrogen (PN) were measured over a two year period, 1983–1985, in the Orinoco River at Ciudad Bolívar, 450 km from its mouth. Additionally, samples of the main stem at other localities and main tributaries were included in the present study.
The suspended sediment concentrations showed a peculiar pattern of temporal variations: two maxima (May–June and November) and two minima (March–April and August–September).
The POC and PN concentrations fluctuated with the water discharge, and higher values were observed during the rising limb than during the falling limb of the hydrograph. As dry weight percent of solids, the values ranged between 0.84 and 9.06% for organic carbon and between 0.08 and 1.45% for total nitrogen. The carbon-nitrogen ratio in the sediment averaged 9.1. The major contribution of organic carbon and nitrogen in particulate form to the Orinoco main stem comes from the left margin tributaries, which have their headwater in the mountainous regions of the Andes.
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References
Cascante EA, Giombi N & Depetris PJ (1985) Abundances and fluxes of inorganic particulate and dissolved phases in the Paraná River (Argentina). Mitt. Geol. Paläont. Inst. Univ. Hamburg 58: 305–310
Degens ET, Kempe S & Richey JE (1991) Biogeochemistry of major world rivers. SCOPE 42. John Wiley & Sons. Chichester pp. 356
Depetris P & Cascante E (1985) Carbon transport in the Paraná River. Mitt. Geol. Paläont. Inst. Univ. Hamburg 58: 299–304
Gordeev VV, Konnov VA & Konnova YV (1992) Nitrogen forms in the Amazon River basin and Estuary. Mitt. Geol. Paläont. Inst. Univ. Hamburg 72: 133–147
Hamilton SK & Lewis WH (1987) Causes of seasonality in the chemistry of a lake on the Orinoco River floodplain, Venezuela. Limnol. Oceanogr. 32: 1277–1290
Hedges JI, Clark WA, Quay PO, Richey JE, Devol AH & Santos V de M (1986) Compositions and fluxes of particulate organic material in the Amazon River. Limnol. Oceanogr. 31: 717–738
Ittekkot V (1988) Global trends in the nature of organic matter in river suspensions. Nature 332: 436–438
Ittekkot V & Zhang S (1989) Pattern of particulate nitrogen transport in world rivers. Global Biogeochemical Cycles. 3: 383–391
Ittekkot V, Martins O & Seifert R (1983) Nitrogenous organic matter transported by the major rivers. Mitt. Geol. Palaont. Inst. Univ. Hamburg 55: 119–127
Kempe S (1988) Freshwater carbon and weathering cycle. In: Physical and chemical weathering in geochemical cycles ( Lerman A & Meybeck M Eds) Kluwer Academic Publishers, Dordrecht. pp. 197–223
Lewis WM Jr. (1988) Primary production in the Orinoco River. Ecology 69: 679–692
Lewis WM & Saunders JF (1989) Concentration and transport of dissolved and suspended substances in the Orinoco River. Biogeochemistry 7: 203–240
Lo H (1984) Le bassin de la Gambie: contribution a l'hydrologie et a la dynamique fluviale en milieu tropical humide africain. These 3éme cycle, Univ. Nancy, 396 pp
Meade RH, Dunne T, Richey JE, Santos U de M & Salati E (1985) Storage and remobilization of suspended sediment in the lower Amazon River of Brazil. Science 228: 488–490
Meade RH, Nordin CF, Pérez-Hernández D, Mejia A, Pérez-Godoy JM (1983) Sediment and water discharge in Rio Orinoco, Venezuela and Colombia. Proceedings of the Second International Symposium on River Sedimentation. Water Resources and Electric Power Press, Beijing. pp. 1134–1144
Meade RH, Weibezahn FH, Lewis WH & Pérez-Henández D (1990) Suspended-sediment budget for the Orinoco River. In: The Orinoco River, as an ecosystem. ( Weibezahn FH, Alvarez H & Lewis WM Eds) Editorial Acta Científica Venezolana, Caracas. pp. 55–79
Meybeck M (1982) Carbon, nitrogen, and phosphorus transport by world rivers. Am. J. Sci. 282: 401–450
Ministerio del Ambiente y los Recursos Naturales (1983) Venezuela en Mapas 1a Edición. Dirección de Cartografía Nacional. p. 42–43. Caracas
Milliman JD, Xie QC & Yang Z (1984) Transfer of particulate organic carbon and nitrogen from the Yangtze River to the Ocean. Am. J. Science 284: 824–834
Paolini J (1986) Transporte de carbono y minerales en el río Caroní. Interciencia 11 (6): 295–297
Paolini J (1991) Organic carbon in the Orinoco River (Venezuela). Verh. Intemt. Verein. Limnol. 24: 2077–2079
Paolini J & Ittekkot V (1990) Particulate organic matter in the Orinoco River. Naturwissenschaften 77: 80–81
Paolini J, Hevia R, Herrera R (1987) Transport of carbon and minerals in the Orinoco and Caroní Rivers during the years 1983–1984. Mitt. Geol. Paläont. Inst. Univ. Hamburg 64: 325–338
Pérez-Hernández D (1985) Investigaciones hidrológicas, sedimentológicas e hidroquímicas recientes en la cuenca del río Orinoco. Universidad Central de Venezuela, Escuela de Ingeniería Civil, Departamento de Metereología, Caracas
Richey JE, Brock JT, Naiman RJ, Wissmar RC & Stallard RF (1980) Organic carbon oxidation and transport in the Amazon River. Science 207: 1348–1351
Robbins LG (1977) Suspended sediment and bed material studies in the lower Mississippi River. US Anny Engineer District, Vickburg, Potamology Investigations Report 300-1
Schlesinger WH & Melack JM (1981) Transport of organic carbon in the world's rivers. Tellus 33: 172–187
Schmidt GW (1972) Amounts of suspended solids and dissolved substances in the middle reaches of the Amazon over the course of one year (August, 1969–July,1970). Amazoniana 3: 208–223
Stevenson FJ (1982) Humus chemistry: genesis, compositions, reactions. John Wiley & Sons, New York
Thurman EM (1985) Organic geochemistry of natural waters. Martinus Nijhoff/Dr. W. Junk Publishers, Dordrecht
Vila P (1960) Geografía de Venezuela. Ediciones del Ministerio de Educación, Tomo 1, Caracas
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Paolini, J. Particulate organic carbon and nitrogen in the Orinoco river (Venezuela). Biogeochemistry 29, 59–70 (1995). https://doi.org/10.1007/BF00002594
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DOI: https://doi.org/10.1007/BF00002594