|Macrofaunal reworking activities and hydrocarbon redistribution in an experimental sediment system|Caradec, S.; Grossi, V.; Hulth, S.; Stora, G.; Gilbert, F. (2004). Macrofaunal reworking activities and hydrocarbon redistribution in an experimental sediment system. J. Sea Res. 52(3): 199-210. dx.doi.org/10.1016/j.seares.2004.02.002
In: Journal of Sea Research. Elsevier/Netherlands Institute for Sea Research: Amsterdam; Den Burg. ISSN 1385-1101, more
Benthos; Bioturbation; Carbon cycle; Hydrocarbons; Sediment dynamics; ANE, Sweden, Gullmarsfjord [Marine Regions]; Marine
|Authors|| || Top |
- Caradec, S.
- Grossi, V.
- Hulth, S.
- Stora, G.
- Gilbert, F., correspondent
The influence of macrofaunal reworking activities on the redistribution of particle associated hydrocarbon compounds (HC) was experimentally investigated. Two distinct hydrocarbon mixtures adsorbed on montmorillonite particles (< 4 m diameter) were added to the surface and deeper (2.5 cm) sediment layers. For comparison, luminophores (100-160 m diameter) were added in the two deposit layers. At the start of the experiment, four macrobenthic species (the bivalve Abra nitida, the polychaete Scalibregma inflatum, and the echinoderms Amphiura filiformis and Echinocardium cordatum) were added to the sediment surface. The macrofauna added rapidly transferred HC from the surface sediment down to ~5 cm depth by both continuous (biodiffusion) and non-continuous (biotransport) transport. Hydrocarbon compounds initially added to the deeper sediment layer were only subject to biodiffusion-like transport. Apparent biodiffusion coefficients (Db) quantified by using a 1-D model were between 0.5 and 8.4×10−3 cm 2 d−1, and biotransport coefficients (r) ranged from 2.0 to 27.6×10−3 d−1. Thus, the four species studied did not have the same effect on particle redistribution and, consequently, on HC repartition in the sediments.E. cordatum was the most efficient reworker. The present study demonstrated the importance of particle size selectivity by benthic fauna, and verified that macrofaunal reworking activities may redeposit sediment from deeper sediment layers on the sediment surface. Both processes have obvious implications for rates and pathways during organic matter mineralisation in marine sediments.