Electrogenic sulfur oxidation in a northern saltmarsh (St. Lawrence Estuary, Canada).
Measurements of porewater O2, pH, and H2S microprofiles in intact sediment cores collected in a northern saltmarsh in the St. Lawrence Estuary (Quebec, Canada) revealed the occurrence of electrogenic sulfur oxidation (e-SOx) by filamentous "cable" bacteria in submerged marsh pond sediments in the high marsh. In summer, the geochemical fingerprint of e-SOx was apparent in intact cores, while in fall, cable bacteria were detected by fluorescence in situ hybridization and the characteristic geochemical signature of e-SOx was observed only upon prolonged incubation. In exposed, unvegetated creek bank sediments sampled in the low marsh in summer, cable bacteria developed only in repacked cores of sieved (500 μm), homogenized sediments. These results suggest that e-SOx is suppressed by the activity of macrofauna in exposed, unvegetated marsh sediments. A reduced abundance of benthic invertebrates may promote e-SOx development in marsh ponds, which are dominant features of subarctic saltmarshes as in the St. Lawrence Estuary.
a Université du Québec à Rimouski, Institut des sciences de la mer, 310 allée des Ursulines, Rimouski, QC G5L 3A1, Canada.
Alexandra
A
Rao
b Center for Geomicrobiology, Section for Microbiology, Department of Bioscience, Aarhus University, Ny Munkegade 114, DK-8000, Aarhus C, Denmark.
Nils
N
Risgaard-Petersen
a Université du Québec à Rimouski, Institut des sciences de la mer, 310 allée des Ursulines, Rimouski, QC G5L 3A1, Canada.
Urs
U
Neumeier
D001419:Bacteria / Q000378:metabolism*; D063366:Estuaries; D005843:Geography; D019015:Geologic Sediments / Q000382:microbiology; D006863:Hydrogen-Ion Concentration; D017404:In Situ Hybridization, Fluorescence; D010084:Oxidation-Reduction; D010100:Oxygen / Q000378:metabolism*; D011792:Quebec; D012621:Seasons; D013455:Sulfur / Q000378:metabolism*; D053833:Wetlands
D013455:Sulfur; D010100:Oxygen
bactéries câbles; cable bacteria; cycle du soufre; electrogenic sulfur oxidation; marais salé; microelectrodes; microélectrodes; oxydation électrogénique du soufre; salt marsh; sulfur cycle