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International Journal of Environment Science and Technology
Center for Environment and Energy Research and Studies (CEERS)
ISSN: 1735-1472
EISSN: 1735-2630
Vol. 10, No. 1, 2013, pp. 55-62
Bioline Code: st13007
Full paper language: English
Document type: Research Article
Document available free of charge

International Journal of Environment Science and Technology, Vol. 10, No. 1, 2013, pp. 55-62

 en Contribution of bacteria to redox potential (Eh) measurements in sediments
Hunting, E.R. & Kampfraath, A.A.

Abstract

Increasing evidence suggests that bacteria are capable of creating specific redox conditions which are visible as species-specific continuous redox potential (Eh) measurements. It has been demonstrated that continuous measurements of Eh are valuable for tracking bacterial metabolic activities of bacterial species in liquid cultures. However, it remains uncertain whether this phenomenon is widespread among bacterial species and whether Eh measurements reflect similar mechanisms in more complex systems such as soils and sediments. The purpose of this study is therefore to evaluate whether bacteria that naturally occur in sediments have the capacity to control Eh and assess the relative partitioning of biological processes involved in Eh in natural sediments. To this end, continuous Eh measurements are linked to growth of bacteria in liquid cultures and bacterial metabolic activity in aquatic sediment microcosms containing the bioturbator Tubifex check for this species in other resources spp., in which we evaluate bacterial partitioning in microcosms treated with the bacteriocide formalin. The tested bacterial species ( Micrococcus luteus check for this species in other resources , Paracoccus pantotrophus check for this species in other resources and Aminobacter aminovarans check for this species in other resources ) appeared to have specific stable Eh signals during linear-exponential growth phase, suggesting that these species are capable of exerting an extracellular control on Eh measurements, thereby supporting the notion that species-specific Eh signals may be widespread among bacterial species. Formalin treatment reduced temporal variability of Eh in sediment microcosms. This outcome suggests that bacterial metabolism and inherent relative contributions of members of bacterial community principally determine development of Eh in sediment systems and that quantitation of sediment electrochemical properties may offer a potential indicator that characterizes bacterial processes.

Keywords
Aquatic sediments; Extracellular; Microbial community; Redox potential; Species-specificity; Tubifex spp.

 
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