| one publication added to basket [142402] | | Geochemical behavior of trace elements in sub-tidal marine sediments of the Belgian coast |  |
| Gao, Y.; Lesven, L.; Gillan, D.; Sabbe, K.; Billon, G.; De Galan, S.; Elskens, M.; Baeyens, W.; Leermakers, M. (2009). Geochemical behavior of trace elements in sub-tidal marine sediments of the Belgian coast Mar. Chem. 117(1-4): 88-96. dx.doi.org/10.1016/j.marchem.2009.05.002 |
| In: Marine Chemistry. Elsevier: Amsterdam. ISSN 0304-4203, meer |
| Trefwoorden |
Kustgebied; Sedimenten; Seizoenale variaties; Sporenelementen; ANE, België, Belgische kust [gazetteer]; Marien |
| Author keywords |
Trace elements; DET; DGT profiles; Sediments; Coastal zone; Seasonal variation |
| Auteurs | | Top |
- Gao, Y. publicatielijst, meer
- Lesven, L., publicatielijst
- Gillan, D. publicatielijst, meer
- Sabbe, K. publicatielijst, meer
- Billon, G., publicatielijst
| |
| Abstract |
High resolution profiles of trace elements (Fe, Mn, Co, As, Cu, Cr, Ni and Pb) were assessed using the DET
(Diffusive Equilibrium in Thin films) and DGT (Diffusive Gradients in Thin films) techniques in silty, organically
enriched, sub-tidal sediments of the Belgian coast during late winter and spring 2008. The general chemical
properties of the sediments such as dissolved oxygen, pH, Eh and sulfide profiles, controlling precipitation/
mobilization reactions, were determined with electrodes (pH and Eh) and microelectrodes (oxygen) and AgIDGT
probes (sulfide).
Most trace elements show subsurface maxima and low concentrations beneath 8 cm of depth. The main
physicochemical parameters controlling the vertical concentration profiles are dissolved oxygen and redox
potential in the surface sediment and sulfide in the deeper sediment layers. Thermodynamic equilibrium
calculations have been carried out verifying which solid phases can explain the dissolved trace metal
concentrations. Seasonal variations of trace elements have been observed during the sampling period and
sedimentation of fresh particulate organic matter (POM) derived from phytoplankton blooms appear to be the
main cause of this temporal variability.
Flux calculations based on DGT profiles (these fluxes are minimum ones) show that exchange fluxes of trace
metals in February are slightly higher than in April. In addition, “DGT pistons” were deployed at the sediment
water interface (SWI) to accumulate labile ions from below. This way all labile ions, binding onto the DGT
Chelex resin, are pumped out of the porewaters and the solid sediment phase (only the mobile fraction). These
results are a direct estimation of the amount of trace elements that can be released from the upper sediment to
the water column (in the range of 4.4·10-5 to 0.10 mmol·m-2·d-1 for Co, Pb, Cr, As, Cu, Ni, Fe and Mn). |
|
