Research interest

I am a microbial ecologist with a deep interest in the diverse interactions between microbes—both with other microorganisms (e.g., bacteria-predatory protists) and with macro-organisms (e.g., plant-microbe)—and how these interactions integrate in different ecosystems. My skills include a range of approaches, from molecular techniques and microscopy in highly controlled laboratory setups to greenhouse experiments that better mimic natural environments.

As part of the DRought Impacts on soil microbial metabolism in European foRests (DRIER) project, I am working to develop and apply hydrogen isotope ratios of phospholipid fatty acids (PLFAs) as indicators of soil microbial metabolism. My goal is to gain a deeper mechanistic understanding of microbial carbon use efficiency (CUE) and to place this knowledge in an ecological context. To achieve this, I will conduct a series of experiments that progressively increase in complexity, starting with simple co-cultures and expanding to soil mesocosms.

Educational background and work experience

2025-ongoing: Postdoctoral Researcher in the Organic Geochemistry group of Prof. Dr. Nemiah Ladd, University Basel (CH)

2022-2024: Scientific collaborator at the Swiss Quality Testing Services (SQTS, CH) (food microbiology)

2018-2022: PhD student in the Ecology and Biodiversity group at the Utrecht University (NL)

Oct – Dec 2016: Research internship in the Ecology and Biodiversity group at the Utrecht University (NL)

2014-2016: Master of Biogeosciences at the University of Neuchâtel and University of Lausanne (CH) with the specialization in Geomicrobiology

Feb – Aug 2016: Scientific mediation for “l’Eprouvette” (Lausanne, CH) (workshops on waste water treatment)

Mar – Jun 2016: Assistantship for the courses Environmental Biogeochemistry and Environmental Pollution at the University of Lausanne (CH)

2011-2014: Bachelor in Biology at the University of Zürich (CH)

Publications

Peer-reviewed articles

Amacker, N., Gao, Z., Hu, J., Jousset, A. L. C., Kowalchuk, G. A, Geisen, S. (2022). Protist feeding patterns and growth rate are related to their predatory impacts on soil bacterial communities. FEMS Microbioloy Ecology, 98:6, fiac057. https://doi.org/10.1093/femsec/fiac057 

Wu X., Jousset, A. L. C, Li, R., Delgado-Baquerizo, M., Bahram, M., Logares, R., Wilden, B., Arjen de Groot, G., Amacker, N., Kowalchuk, G. A., Shen, Q., Geisen, S. (2021) A global overview of the trophic structure within microbiomes across ecosystems. Environment International, 151, 106438https://doi.org/10.1016/j.envint.2021.106438

Amacker, N., Gao, Z., Agaras, B. C., Latz, E., Kowalchuk, G. A., Valverde, C. F., Jousset, A., Weidner, S. (2020). Biocontrol traits correlate with resistance to predation by protists in soil Pseudomonads. Frontiers in Microbiology, 15:11, 614194. https://doi.org/10.3389/fmicb.2020.614194

Amacker, N., Mitchell, E. A. D., Ferrari, B. J. D., Chèvre, N. (2018) Development of a new ecotoxicological assay using the testate amoeba Euglypha rotunda (Rhizaria; Euglyphida) and assessment of the impact of the herbicide S-metolachlor. Chemosphere, 201:351-360. https://doi.org/10.1016/j.chemosphere.2018.03.001

Additional contributions

Geisen S., Amacker, N., Jousset, A. L. C. (2023) Soil protist. Encyclopedia of Soils in the Environment, Second Edition, 1:39-48,  https://doi.org/10.1016/B978-0-12-822974-3.00075-6 - Book chapter

Amacker, N., (2022) The case of the predatory protists. FEMS Microbiology Ecology Webinar on Microbial Life Strategies. https://youtu.be/9svvnb0xXyc?t=1354

Amacker, N., Gao, Z. (2021) Bodemprotisten en hun rol bij het onderdrukken van ziekteverwekkers. Gewasbescherming, 52:6. https://knpv.org/db/upload/documents/Gewasbescherming/2021gb52nr6.pdf