Invertebrate footprints on detritus processing, bacterial community structure, and spatiotemporal redox profiles

Contribution of bacteria to redox potential (E h) measurements in sediments

“…Taken together, measurements of E h in complex natural systems seem to reflect the metabolic activity of resident bacterial communities rather than concentrations of terminal electron acceptors in our microcosms. This complements previous studies that linked E h to bacterial activity and community structure (Bertics and Ziebis 2009;Hunting and Van der Geest 2011;Hunting et al 2012). Although it cannot be ruled out that E h measurements may still be overruled by redox couples unrelated to bacterial activity, quantitation of the electrochemical properties of the sediment may offer a potential indicator of bacterial processes in sediment systems.…”

Tube‐dwelling invertebrates: tiny ecosystem engineers have large effects in lake ecosystems

“…Bioturbation and feeding activities of tube-dwelling invertebrates change the general community structure of sediment bacteria, as demonstrated with molecular fingerprinting techniques (Hunting et al 2012, Zeng et al 2014. In contrast, the total abundance of sediment bacteria remains largely unaffected or increases only slightly in the presence of tube-dwelling invertebrates (Van de Bund et al 1994, Wieltschnig et al 2008.…”

“…Tube-dwelling invertebrates commonly stimulate microbial organic matter degradation and mineralization through bioturbation and feeding activities. Enhanced mineralization rates in and around the tubes of tubedwelling invertebrates in concert with pumping activity lead to increased fluxes of CO 2 and DOC from the sediment into the water column (Goedkoop et al 1997, Hansen et al 1998, Stief 2007, Hunting et al 2012. Aside from the carbon cycle, microbial roles in the phosphorus and nitrogen cycles also are greatly affected by tubedwelling invertebrates.…”

Benthic Invertebrate Bioturbation Activity Determines Species Specific Sensitivity to Sediment Contamination

“…Chironomids can, nevertheless, increase oxygen penetration depth or sediment oxygen consumption , but the redox values in the sediment remain generally reducing. Hunting et al (2012) also observed low oxygen concentrations and reducing conditions around chironomids and oligochaetes, thus potentially increasing AVS concentration. In contrast, the epifaunal biodiffusor A. aquaticus increased the sediment oxygen concentration by its bioturbation activities (Hunting et al, 2012), which may lead to a decrease in AVS concentration.…”

“…Hunting et al (2012) also observed low oxygen concentrations and reducing conditions around chironomids and oligochaetes, thus potentially increasing AVS concentration. In contrast, the epifaunal biodiffusor A. aquaticus increased the sediment oxygen concentration by its bioturbation activities (Hunting et al, 2012), which may lead to a decrease in AVS concentration. In agreement, Vandegehuchte et al (2013) demonstrated that the presence of G. pulex decreased the AVS concentration in the sediment, while the mayfly E. virgo had little effect on the AVS concentration and the presence of the oligochaete L. variegatus resulted in an increase in AVS concentration in the sediment.…”