Phenotyping bacterial microbiomes to identify physiological capacities and quantify heterotrophy in situ.

• Applicant: Dr. Greta Reintjes
• Subject Area: Microbial Ecology and Applied Microbiology ; Metabolism, Biochemistry and Genetics of Microorganisms
• Term: since 2022
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 496342779

The overall goal of this research project is to acquire a phenotypic understanding of how marine microbial heterotrophs process glycans in the oceans. Marine heterotrophic activity is one of the largest and most dynamic components of the Earth's carbon cycle. Currently, microbiologists predominantly analyse the genetic content of microbes (genotype) to deduce the organism's potential to degrade individual glycans. However, these analyses do not determine if the potential functions are being performed in a given time and space (phenotype). To truly identify and quantify microbial metabolic capacities, we must take the next step and phenotypically describe microbial functions in situ. Therefore, in this project, we will use novel phenotypic approaches to 1) identify the mechanisms by which individual marine heterotrophs process individual glycans, 2) quantify their rate of activity in situ, 3) discover if they behave cooperatively or competitively, and 4) determine how their foraging behaviour affects organic matter turnover in the oceans. Additionally, using our discoveries, we will investigate two of the central elements influencing microbially driven carbon cycling: resource competition and syntrophy (metabolic cross-feeding). The project will combine techniques, including novel next-generation physiology approaches, flow cytometry, glycobiology, microbiology, and molecular ecological methods. This diverse combination will allow us to classify microbial heterotrophs by their specific function and quantify their metabolic capacity at a given time within a given ecosystem. The scientific discoveries of this project will enable us to understand the broader effects that individual microbes have on microbial community structure and functioning. This allows us to comprehend the microbial turnover of organic matter and to better understand how this affects the oceans' largest and most dynamic pool of carbon.

• DFG Programme: Independent Junior Research Groups
• Major Instrumentation: HPLC system
• Instrumentation Group: 1350 Flüssigkeits-Chromatographen (außer Aminosäureanalysatoren 317), Ionenaustauscher