TY - JOUR T1 - Input of particulate organic and dissolved inorganic carbon from the Amazon to the Atlantic Ocean JF - Geochemistry Geophysics Geosystems Y1 - 2005 A1 - Druffel, E. R. M. A1 - Bauer, J. E. A1 - Griffin, S. KW - accumulation KW - amazon KW - C-14 KW - carbon cycling KW - CO2 KW - continental-shelf KW - poc KW - radiocarbon KW - river system KW - Sediment KW - total co(2) KW - water AB - We report concentrations and isotope measurements (radiocarbon and stable carbon) of dissolved inorganic carbon (DIC) and suspended particulate organic carbon (POC) in waters collected from the mouth of the Amazon River and the North Brazil Current. Samples were collected in November 1991, when the Amazon hydrograph was at its annual minimum and the North Brazil Current had retroflected into the equatorial North Atlantic. The DIC D 14 C results revealed postbomb carbon in river and ocean waters, with slightly higher values at the river mouth. The low DIC delta(13)C signature of the river end-member (-11%) demonstrates that about half of the DIC originated from the remineralization of terrestrially derived organic matter. A linear relationship between DIC and salinity indicates that DIC was mixed nearly conservatively in the transition zone from the river mouth to the open ocean, though there was a small amount (<= 10%) of organic matter remineralization in the mesohaline region. The POC Delta(14)C values in the river mouth were markedly lower than those values from the western Amazon region (Hedges et al., 1986). We conclude that the dominant source of POC near the river mouth and in the inner Amazon plume during November 1991 was aged, resuspended material of significant terrestrial character derived from shelf sediments, while the outer plume contained mainly marine-derived POC. VL - 6 SN - 1525-2027 N1 - 909pwTimes Cited:17 Cited References Count:21 JO - Geochem Geophy Geosy ER -