Silicon and sediment transport of the Changjiang River (Yangtze River): could the Three Gorges Reservoir be a filter?

摘要: Water samples were collected from the Changjiang River (Yangtze River) in May 2005, after impoundment of Three Gorges Reservoir (TGR), to examine influence TGR and large lakes on material delivery estuary River. The concentrations suspended particle (SPM), dissolved silica (DSi) biogenic (BSi) main stream analyzed. DSi BSi channel varied between 73 100 1.1–15 μmol/l, with a distance weighted average 81 8.0 respectively. A calculation shows that live diatom comprises only an value 5.2 % River, most may come drainage basin. ratios BSi/SPM relatively low compared other rivers throughout world, but carried suspension by was important component silicon load (i.e. ~13 %). SPM, as observed tend decrease upper sections river Dam (TGD), reflecting sedimentation associated trapping retention normal-water period. SPM are more strongly influenced TGD DSi. About 98 72 16 retained within 2005. fluxes variations DSi, suggested dams had coupled effect transportation Such change (DSi BSi) balances will affect ecological environment its adjacent sea some extent.