SedSulphOx · Quantification of oxidative sulphur cycling in marine sediments
Horizon 2020 — Marie Skłodowska-Curie Actions
- Duration
- 2017-06-01 → 2019-05-31
- EU contribution
- €200,195
- Participants
- 1
- Scheme
- MSCA-IF-EF-ST
Lines connect the coordinator with its partners.
Results in brief
Quantification of oxidative sulphur cycling in marine sediments
The goal of this project was to measure transformations of different sulphur compounds in marine sediments, particularly sulphide oxidation to sulphate. Sulphide is produced through microbial sulphate reduction, a key process for the remineralisation of organic matter to CO2 in the seafloor. Understanding this process is societally relevant because fluxes of inorganic carbon and reduced sulphur from the sediments have a profound effect on the oxygen balance and carbon uptake capacity of coastal waters, which in turn plays a role in regulating atmospheric CO2. Moreover, carbon and nutrient loading to coastal waters such as the Baltic Sea are heightened due to human activities. Such conditions lead to eutrophication of the water column and sulphide release from the sediment. Sulphide is toxic to aerobic organisms such as fish, and negatively impacts the water quality. Knowing how much and how quickly sulphur is cycled in coastal sediments is therefore an important component to better understand broader scale carbon cycling and controls on local water quality. Thus, the overall objective of this project was to quantify sulphide oxidation rates in marine sediments.
Data: CORDIS, © European Union
Project objective
The goal of this proposal is to quantify the rates and processes of sulphide oxidation in coastal sediments. The marine sulphur cycle is driven by the reduction of sulphate to sulphide coupled to microbial decomposition of organic matter, a process which is responsible for up to 50 % of carbon mineralisation in coastal sediment and is intimately connected to earth’s biogeochemical evolution. The sulphide produced by sulphate reduction may either react with Fe to be buried as pyrite or may be oxidised through different pathways and intermediates. The amount of sulphide that is oxidised in marine sediments is not known, yet oxidative sulphur cycling has critical implications for estimates of sulphate reduction, sub-seafloor carbon mineralisation, methane oxidation, microbial metabolism and the interpretation of ancient and modern stable isotope signatures. Quantification of oxidative sulphur cycling, including sulphide oxidation rates, the formation of key intermediate species and associated stable isotope effects is therefore fundamental to our understanding of sub-seafloor biogeochemistry. The research proposed herein will address these yet unanswered questions through a novel combination of radiotracer experiments, stable isotope measurements, and analyses of inorganic sulphur speciation. This approach will be applied to (1) quantify rates of concurrent sulphate reduction and sulphide oxidation in coastal sediment, (2) quantify the formation of intermediate species formed during sulphide oxidation and (3) measure stable isotope effects associated with oxidative sulphur cycling. This work will result in a more accurate description of sediment biogeochemistry by resolving current debates regarding the role of sulphur for carbon mineralisation ad further constraining processes which affect the sulphur stable isotope distribution.
Original text from CORDIS.
Participants
- AARHUS UNIVERSITET · Aarhus CCoordinatorDenmark
Links
Data: CORDIS, © European Union