Séminaire "Cable bacteria: A brief summary of 10 years research in an organism and its environmental implications" par Nils Risgaard-Petersen - Univ. Aarhus

Jeudi 02 Décembre 2021, 13:00 - 14:00
par Stéphanie BEAUNAY

In this talk I will give a brief summary of the results from my research in cable bacteria.  Cable bacteria are filamentous bacteria of the Desulfubulbacea family with a unique metabolism, which we call electrogenic sulfide oxidation.  I discovered them back in 2011, but evidence for their presence were already there in 2007. During the long period from 2007 till today we have learned a lot about the organism and its environmental impact. We know now that Cable bacteria of different genera are present in both freshwater and marine sediments around the globe. Their peculiar metabolism, which includes electron transfer over cm long distances, the oxidation of sulfides and the reduction of oxygen and nitrate is becoming more and more constrained with data. From experiments and field studies we know that the cable bacteria can have a strong influence on elemental cycling in sediments.  These effects can be seen as side effects of the primary implications of the cable bacteria metabolism which includes the acidification of oxygen free zones, the removal of sulfide, the accumulation of sulfate and the generation of electric fields. These features can induce a cascade of events that include the mobilization iron and carbonate minerals, the enhancement of sulfur cycling and changes in the way nitrogen is transformed. Studies have shown that these cable bacteria mediated impacts can have a beneficial environmental effect such as the retention of toxic hydrogen sulfide in oxygen poor sediments.  Our recent studies even suggest that cable bacteria can initiate  the reduction  methane emissions from rice vegetated soils by up till 90 pct.