A H₂S microsensor for profiling biofilms and sediments: Application in an acidic lake sediment

TY - JOUR

T1 - A H2S microsensor for profiling biofilms and sediments

T2 - Application in an acidic lake sediment

AU - Kühl, Michael

AU - Steuckart, Carsten

AU - Eickert, Gabriele

AU - Jeroschewski, Paul

PY - 1998/1/1

Y1 - 1998/1/1

N2 - We developed a microsensor for the amperometric detection of dissolved hydrogen sulfide, H2S, in sediments and biofilms. The microsensor exhibits a fast (t90 <0.2 to 0.5 s) and linear response to H2S over a concentration range of 1 to >1000 μmol H2S l-1, and has a low stirring dependency of the microsensor signal (<1 to 2%). We used the new microsensor to obtain the first microprofiles of H2S in an acidic lake sediment with a several cm thick flocculant surface layer. Despite the low pH of 4.6, a relative low SO4 2- level in the lake water, and a broad O2 respiration zone of ca 6 mm, we were able to measure H2S depth profiles in the sediment at a good resolution, that allowed for calculation of specific sulfate reduction and H2S oxidation activities. Such calculations showed highest sulfate reduction activity in the anoxic sediment down to ca 20 mm depth. A comparison of calculated areal rates of O2 consumption and sulfate reduction indicated that sulfate reduction accounted for up to 13% of total organic carbon mineralization in the acidic sediment. All produced H2S was reoxidizecl aerobically with O2 at the oxic-anoxic interface. In addition to its good performance in acidic environments, the new H2S microsensor has proven useful for sulfide measurements in neutral and moderate alkaline (pH < 9) biofilms and sediments, and thus is a true alternative to the traditionally used potentiometric Ag/Ag2S microelectrode for most applications in aquatic ecology and biogeochemistry.

AB - We developed a microsensor for the amperometric detection of dissolved hydrogen sulfide, H2S, in sediments and biofilms. The microsensor exhibits a fast (t90 <0.2 to 0.5 s) and linear response to H2S over a concentration range of 1 to >1000 μmol H2S l-1, and has a low stirring dependency of the microsensor signal (<1 to 2%). We used the new microsensor to obtain the first microprofiles of H2S in an acidic lake sediment with a several cm thick flocculant surface layer. Despite the low pH of 4.6, a relative low SO4 2- level in the lake water, and a broad O2 respiration zone of ca 6 mm, we were able to measure H2S depth profiles in the sediment at a good resolution, that allowed for calculation of specific sulfate reduction and H2S oxidation activities. Such calculations showed highest sulfate reduction activity in the anoxic sediment down to ca 20 mm depth. A comparison of calculated areal rates of O2 consumption and sulfate reduction indicated that sulfate reduction accounted for up to 13% of total organic carbon mineralization in the acidic sediment. All produced H2S was reoxidizecl aerobically with O2 at the oxic-anoxic interface. In addition to its good performance in acidic environments, the new H2S microsensor has proven useful for sulfide measurements in neutral and moderate alkaline (pH < 9) biofilms and sediments, and thus is a true alternative to the traditionally used potentiometric Ag/Ag2S microelectrode for most applications in aquatic ecology and biogeochemistry.

KW - Acidic sediment

KW - Freshwater

KW - Hydrogen sulfide

KW - Microsensor

KW - Sulfate reduction

KW - Sulfide oxidation

UR - http://www.scopus.com/inward/record.url?scp=1542605767&partnerID=8YFLogxK

U2 - 10.3354/ame015201

DO - 10.3354/ame015201

M3 - Journal article

AN - SCOPUS:1542605767

SN - 0948-3055

VL - 15

SP - 201

EP - 209

JO - Aquatic Microbial Ecology

JF - Aquatic Microbial Ecology

IS - 2

ER -