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Secondary production by microorganisms in marine sediments and their role in shaping the OM pool

 
 

Within the Cross-Cutting Enabler “Molecular and Isotopic Tracers”, this project (April 2020- March 2024) lies in the general area of organic-matter degradation. The traditional organic geochemical view of organic matter processing focuses on degradation and largely ignores secondary production. Here we propose to answer the question of whether secondary production is important for the composition of the organic matter eventually buried. We aim to use a combination of techniques, in particular, molecular and isotopic tracers (e.g. stable isotope probing, SIP) to follow the flow of carbon and nitrogen and to assess whether the identity of the organisms involved does matter or not. We use 13C and 15N labeled substrates to incubate sediments from Helgoland and try to quantify the lipid and protein pool reshaped by organisms. Furthermore, we also try to explore the microbial community that is heavily involved in the reworking of the OM pool (cooperating with Dr. Xiuran Yin). Related to the above, we would like to make use of the large collection of sediments available at MARUM to investigate whether sedimentary bacteria are flexible in terms of elemental stoichiometry. The project is led by Uni Bremen Excellence Chair Jack Middelburg, who is jointly affiliated with the Universities of Utrecht and Bremen. I will update my research on my website (https://qingzeng.rbind.io/) from time to time and welcome to contact me for cooperation.