ISSN:
1573-2932
Keywords:
diffusion
;
alkalinity
;
sediment-water interface
;
southwestern Chinese plateau
;
carbonates
;
carbon isotopes
Source:
Springer Online Journal Archives 1860-2000
Topics:
Energy, Environment Protection, Nuclear Power Engineering
Notes:
Abstract Sediments were cored, and the sediment-water interface and overlying waters were sampled in 5 lakes from the southwestern Chinese plateau during 1991-95. The geochemistry of HCO3 − at the sediment-water interface was examined by studying detailed profiles of pH, HCO3 − concentrations and 813C of dissolved inorganic carbon (DIC) in overlying lake water and porcwater near the sediment-water interface. Dissolution-precipitation equilibrium of carbonates, diffusion flux, and the extent of the influence of diffusion on the whole lake were calculated. The results show that the HCO3 − near the interface carried isotopic characteristics of decomposition of organic matter during early diagenesis, and that the porcwater in surface sediments was unsaturated relative to calcite, and gradually saturated with depth. Furthermore, the interface is a source of HCO3 to the overlying water. Alkalinity (Alk) diffusion flux from sediments to the overlying water due to concentration gradients ranged front 0.51 to 24.33 × 104 mol cm−2 a−1. The calculated contribution of the diffusion of Alk to the overlying water ranged from 0.46% to 49.42%. Diffusion is an important source of Alk in lakes with a long residence time and a relatively shallow depth.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF02406878
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