The Importance of Microbial Iron Sulfide Oxidation for Nitrate Depletion in Anoxic Danish Sediments

TY - JOUR

T1 - The Importance of Microbial Iron Sulfide Oxidation for Nitrate Depletion in Anoxic Danish Sediments

AU - Vaclavkova, Sarka

AU - Jacobsen, Ole Stig

AU - Jørgensen, Christian Juncher

AU - Aamand, Jens

AU - Elberling, Bo

PY - 2014/7

Y1 - 2014/7

N2 - Nitrate (NO3 −) reduction processes are important for depleting the NO3 − load from agricultural source areas before the discharge water reaches surface waters or groundwater aquifers. In this study, we experimentally demonstrate the co-occurrence of microbial iron sulfide oxidation by NO3 − (MISON) and other NO3 −-depleting processes in a range of contrasting sediment types: sandy groundwater aquifer, non-managed minerotrophic freshwater peat and two brackish muddy sediments. Approximately 1/3 of the net NO3 − reduction was caused by MISON in three of the four environments despite the presence of organic carbon in the sediment. An apparent salinity limitation to MISON was observed in the most brackish environment. Addition of high surface area synthetically precipitated iron sulfide (FeS x ) to the aquifer sediment with the lowest natural FeS x reactivity increased both the relative fraction of NO3 − reduction linked to MISON from approximately 30–100 % and the absolute rates by a factor of 17, showing that the potential for MISON-related NO3 − reduction is environmentally significant and rate limited by the availability of reactive FeS x

AB - Nitrate (NO3 −) reduction processes are important for depleting the NO3 − load from agricultural source areas before the discharge water reaches surface waters or groundwater aquifers. In this study, we experimentally demonstrate the co-occurrence of microbial iron sulfide oxidation by NO3 − (MISON) and other NO3 −-depleting processes in a range of contrasting sediment types: sandy groundwater aquifer, non-managed minerotrophic freshwater peat and two brackish muddy sediments. Approximately 1/3 of the net NO3 − reduction was caused by MISON in three of the four environments despite the presence of organic carbon in the sediment. An apparent salinity limitation to MISON was observed in the most brackish environment. Addition of high surface area synthetically precipitated iron sulfide (FeS x ) to the aquifer sediment with the lowest natural FeS x reactivity increased both the relative fraction of NO3 − reduction linked to MISON from approximately 30–100 % and the absolute rates by a factor of 17, showing that the potential for MISON-related NO3 − reduction is environmentally significant and rate limited by the availability of reactive FeS x

U2 - 10.1007/s10498-014-9227-x

DO - 10.1007/s10498-014-9227-x

M3 - Journal article

SN - 1380-6165

VL - 20

SP - 419

EP - 435

JO - Aquatic Geochemistry

JF - Aquatic Geochemistry

IS - 4

ER -