Variations spatio-temporelles des matieres en suspension dans I'estuaire du Sinnamary, Guyane française: influence du barrage hydroélectrique de Petit Saut

Abstract

The coast of French Guiana is subjected to the Amazon dispersal system, whieh is influenced by oceanie currents and trade winds ruled by the position of the Intertropical Convergence Zone. The Sinnamary is one of the major French Guiam\ Tivers. Since 1994, the hydroelectriç dam Qf "P~tit Saut" has modified the hydrological regime and the ecological functioning af th~estuary. Variations in suspended material (orglU1ic and inorganic) concentrations, and paflJmeterssuco as salinity, temperature, dissolved oxygen and chlorophyll has been followed up ffóm measurement carried out between December 1996 and February 1998 in the estuary. The load varií:idlieasonal1yand according to the tide. To establish space-time variability, three variation fa.ctors (depth, time and tidal variation) have been tested. The effects were significant for sa.linity,chlorophyU and the total particulate matter load. Suspended material is four

Dynamics of the Estuarine Turbidity Maximum Zone from Landsat-8 Data: The Case of the Maroni River Estuary, French Guiana

“…Under high river discharge, relatively high SPM values are observed at the upstream part of the estuary, especially at the west bank (Figure 5b). Even though the suspended sediment supply of French Guiana rivers [42], and the Maroni River in particular, is low, the sharp increase in anthropogenic activities over the last decade, notably gold mining in this river's catchment, especially along the border with Suriname [44], could explain the relatively high values along the west bank of the river during these high river flow conditions.…”

“…Two large tidal creek networks debouch on the river's east bank near the mouth, and a series of shoals and vegetated islands have accumulated between KP 15 and KP 26.5 (Figure 1c). The total suspended solid concentration in French Guiana rivers is low [42], and the Maroni has been identified as among the world's rivers with the lowest concentrations [43], no doubt a reflection of the highly crystalline basement rocks and still largely forested nature of the catchments. However, Gallay et al [44] identified a notable 239% increase in the Maroni River's SPM after 2009 due to an upsurge in anthropogenic activities, notably gold mining and deforestation.…”

Effects of the tide on the temporal and spatial physicochemical structure of the Kienké river estuary (South Atlantic Coast of Cameroon, Kribi) and its phytoplankton

“…The mean concentrations of SPM contained in the water increase from downstream to upstream during both low and high tides. This gradient was observed by Amzough (1999) in the Oum Er-rbia estuary in Morocco, and by Maia & Clavier (2000) in the Sinnamary estuary in French Guiana.…”

Fluvial sand, Amazon mud, and sediment accommodation in the tropical Maroni River estuary: Controls on the transition from estuary to delta and chenier plain

“…Rousseau et al (2019) showed that the Maroni's seasonality index, defined as the ratio between the highest and lowest monthly discharge, is much higher than that of the Amazon, thus highlighting the strongly seasonal character of the river's water discharge as well as a catchment-dampening and flowsmoothing capacity on water discharge that are much smaller than those of the much larger Amazon. The Maroni has been identified as among the world's rivers with the lowest suspended sediment concentrations (Sondag et al, 2010), a characteristic shared by other Guiana Shield rivers (Oliveira and Clavier, 2000). This reflects, no doubt, the highly crystalline basement rocks but also the still largely forested nature of the catchments.…”