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
spp., in which we evaluate bacterial partitioning in microcosms treated with the bacteriocide formalin. The tested bacterial species (
Micrococcus luteus
,
Paracoccus pantotrophus
and
Aminobacter aminovarans
) 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.
