The Temperature Dependence of Genome Evolution in Cold-Adapted Planktonic Microbes

Dr. David K. Ngugi, GEOMAR

Freshwater biodiversity is collapsing four times faster than in the oceans, threatening global supplies of clean drinking water. Deep in Europe’s lakes, unique planktonic microbes have lived in a 4 °C deep-freeze for millennia. Because it is so cold, they grow extremely slowly—some remain genetic clones for decades. But time is running out. Climate change is rapidly heating these lakes, forcing these ancient, slow-growing microbes into an unprecedented evolutionary race. A major unanswered question is how quickly such microorganisms can adapt after remaining genomically static for so long. Will rising temperatures accelerate their metabolism and mutation rates, or will they fail to keep pace with a warming world?

In this high-impact MSc project, you will work in the lab to tinker with evolution. You will conduct microbial evolution experiments on unique, cold-adapted planktonic microbes, simulate climate change by culturing organisms at different temperatures over multiple generations, and track genetic changes to measure how temperature affects mutation, phenotypic plasticity, and survival rates. By choosing this project, you will gain advanced skills in experimental evolution, microbial culturing, and quantitative data analysis. The project directly advances our understanding of aquatic conservation and climate change resilience, addressing a major, unresolved ecological question with strong potential for impactful publication. The Master’s thesis will be completed in the Aquatic Microbial Eco-genomics Group (AquaMEG), RU Marine Symbioses at GEOMAR Helmholtz Centre for Ocean Research in Kiel. Contact David Ngugi (dngugi(at)geomar.de) for more information.

The sponge resistome along the Schwentine

Dr. David K. Ngugi, GEOMAR

The river Schwentine is vital to Kiel's drinking water supply. Despite its natural reputation, the river's history is closely tied to Kiel's industrial development, including shipyards, hydroelectric power plants and sewage systems. Its animal inhabitants and associated microbes may reflect this human influence and are of concern as reservoirs of antimicrobial resistance (AMR).

We will study antimicrobial resistance in the Schwentine River using metagenomics and metatranscriptomics. Freshwater sponges are a model reservoir for AMR: they filter 95% of microbes in water, including antibiotic-resistant genes. The project aims to understand if freshwater sponges store ARGs that can be transferred to other microbes and passed up the food chain into drinking water. The MSc thesis will be carried out at GEOMAR Helmholtz Centre for Ocean Research in Kiel. Contact David Ngugi (dngugi@geomar.de) for more information.