IMIS | Flanders Marine Institute
 

Flanders Marine Institute

Platform for marine research

IMIS

Publications | Institutes | Persons | Datasets | Projects | Maps
[ report an error in this record ]basket (0): add | show Print this page

The influence of bioturbation on iron and sulphur cycling in marine sediments: a model analysis
van de Velde, S.; Meysman, F.J.R. (2016). The influence of bioturbation on iron and sulphur cycling in marine sediments: a model analysis. Aquat. Geochem. 22(5): 469-504. https://dx.doi.org/10.1007/s10498-016-9301-7
In: Aquatic Geochemistry. Springer/Springer Science+Business Media: London; Dordrecht; Boston. ISSN 1380-6165; e-ISSN 1573-1421, more
Related to:
Van de Velde, S. (2018). The influence of bioturbation on iron and sulphur cycling in marine sediments: a model analysis, in: Van de Velde, S. Electron shuttling and elemental cycling in the seafloor. pp. 185-232, more
Peer reviewed article  

Available in  Authors 

Keyword
    Marine
Author keywords
    Reactive transport modelling; Diagenetic cycling; Iron; Sulphur; Bioturbation; Bio-mixing; Bio-irrigation

Authors  Top 
  • van de Velde, S., more
  • Meysman, F.J.R., more

Abstract
    The geochemical cycles of iron and sulphur in marine sediments are strongly intertwined and give rise to a complex network of redox and precipitation reactions. Bioturbation refers to all modes of transport of particles and solutes induced by larger organisms, and in the present-day seafloor, bioturbation is one of the most important factors controlling the biogeochemical cycling of iron and sulphur. To better understand how bioturbation controls Fe and S cycling, we developed reactive transport model of a coastal sediment impacted by faunal activity. Subsequently, we performed a model sensitivity analysis, separately investigating the two different transport modes of bioturbation, i.e. bio-mixing (solid particle transport) and bio-irrigation (enhanced solute transport). This analysis reveals that bio-mixing and bio-irrigation have distinct—and largely opposing effects on both the iron and sulphur cycles. Bio-mixing enhances transport between the oxic and suboxic zones, thus promoting the reduction of oxidised species (e.g. iron oxyhydroxides) and the oxidation of reduced species (e.g. iron sulphides). Through the re-oxidation of iron sulphides, bio-mixing strongly enhances the recycling of Fe and S between their reduced and oxidised states. Bio-irrigation on the other hand removes reduced solutes, i.e. ferrous iron and free sulphide, from the sediment pore water. These reduced species are then reoxidised in the overlying water and not recycled within the sediment column, which leads to a decrease in Fe and S recycling. Overall, our results demonstrate that the ecology of the macrofauna (inducing bio-mixing or bio-irrigation, or both) matters when assessing their impact on sediment geochemistry. This finding seems particularly relevant for sedimentary cycling across Cambrian transition, when benthic fauna started colonizing and reworking the seafloor.

All data in the Integrated Marine Information System (IMIS) is subject to the VLIZ privacy policy Top | Authors