Imaging Oxygen Distribution in Marine Sediments. The Importance of Bioturbation and Sediment Heterogeneity

Abstract

The influence of sediment oxygen heterogeneity, due to bioturbation, on diffusive oxygen flux was investigated. Laboratory experiments were carried out with 3 macrobenthic species presenting different bioturbation behaviour patterns: the polychaetes Nereis diversicolor and Nereis virens, both constructing ventilated galleries in the sediment column, and the gastropod Cyclope neritea, a burrowing species which does not build any structure. Oxygen two-dimensional distribution in sediments was quantified by means of the optical planar optode technique. Diffusive oxygen fluxes (mean and integrated) and a variability index were calculated on the captured oxygen images. All species increased sediment oxygen heterogeneity compared to the controls without animals. This was particularly noticeable with the polychaetes because of the construction of more or less complex burrows. Integrated diffusive oxygen flux increased with oxygen heterogeneity due to the production of interface available for solute exchanges between overlying water and sediments. This work shows that sediment heterogeneity is an important feature of the control of oxygen exchanges at the sediment-water interface.

The impact of sediment bioturbation by secondary organisms on metal bioavailability, bioaccumulation and toxicity to target organisms in benthic bioassays: Implications for sediment quality assessment

“…This is clearly shown by studies with amphipods (Corophium volutator), polychaete worms (Lumbriculus variegatus, Arenicola marina, Nereis diversicolor, Nereis virens, Heteromastus filiformis and Tubifex tubifex), bivalves (Tellina texana, Macoma balthica and Cyclope neritea), and sea cucumbers (Holothuria whitmaei) (Aller and Yingst, 1985;De Backer et al, 2011;Lagauzère et al, 2009;Peterson et al, 1996;Pischedda et al, 2008;Shiell and Knott, 2010;Volkenborn et al, 2010). Community structure and population density are further factors which influence the extent of sediment disturbance by organisms (Forbes, 1994;Thrush et al, 2006;Wethey et al, 2001).…”

“…Metal fluxes are exacerbated by sediment-organism interactions, particularly the degree/intensity of bioturbation which is dependent on organism type, population density and sediment composition (particle size, partitioning, AVS and TOC content) and the properties, concentration and form of the metal (Peterson et al, 1996;Pischedda et al, 2008;Volkenborn et al, 2010).…”

“…The bioturbation of sediments by large benthic invertebrates alters sediment redox chemistry by mixing pre-stratified zones in the sediment, and increasing the penetration of electron acceptors such as dissolved O 2 , NO 3 -and SO 4 2-into anoxic sediments (Aller et al, 2001;Granéli, 1979;Matisoff et al, 1985;Pischedda et al, 2008; Volkenborn et al, 2010). Redox changes can alter metal binding affinities between the solid and dissolved phases, significantly modifying the speciation and bioavailability of most metals in sediments (De Jonge et al, 2012;Doyle and Otte, 1997;Granberg et al, 2008).…”

Oxygen microprofile in the prepared sediments and its implication for the sediment oxygen consuming process in a heavily polluted river of China

“…The smooth decrease in DO concentration in sediment pore water in the type I profile likely resulted from the homogenous sediment and thus the uniformly distributed DO reaction rate. This is because both sediment heterogeneity (Pischedda et al 2008) and DO reaction rate (Cai and Sayles 1996) are key factors influencing the distribution of DO in sediment. The DO fluctuation in the type II profile may be caused by the bioturbation of fauna existing in the sediment.…”

Untitled

“…Planar optode measurements offer a unique opportunity to resolve both spatial and temporal variations on a submillimeter scale for a range of analytes. So far, the majority of planar optode studies have been focused on O 2 dynamics in marine sediments including the investigation of microbial mats and biofilms (Glud et al 1998(Glud et al , 1999Fenchel and Glud 2000); effects of bioturbating/irrigating fauna (Behrens et al 2007;Volkenborn et al 2010;Pischedda et al 2008); O 2 dynamics in rhizospheres (Jensen et al 2005;Frederiksen and Glud 2006); and studies of O 2 distribution in permeable sediments (Precht et al 2004;Polerecky et al 2005;Franke et al 2006;Cook et al 2007). Recently, measurements in sea-ice have also provided promising results for resolving physical and biologically induced O 2 dynamics (Rysgaard et al 2008).…”