Variation of organic matter extracted from particles along the Gironde Estuary (France)

Abstract Organic matter was extracted from particles suspended in the Gironde Estuary using a sodium pyrophosphate—sodium hydroxide mixture as extractant. The organic carbon was measured for each fraction obtained during the chemical extraction in order to assess the mass balance. The variation in percentage of the extractible fraction was examined. No significant variations were found either between estuarine zones or with the seasons. The high constancy of the behavior of extractible organic matter in the estuary seems to indicate that this fraction behaves as a chemically stabilized mature material, because neither the passage through the high-turbidity zone nor mixing with marine water change the percentage of this fraction in the particulate organic matter.