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 effects of climate change on antibiotic resistance development in commercially relevant fish species

Dr. Hassan Humeida, Dr. Jutta Wiese, GEOMAR

The oceans contribute 20% of animal protein to human diets worldwide and are even involved in meeting 50% of protein needs in poor countries. Climate change is impacting not only marine organisms but also the microbiomes that live on or within them. At the same time, the demand for food from the sea is increasing globally along with annual human population growth worldwide. Marine food sources are not infinite and their biodiversity is threatened by various factors, including human pollution and overfishing.  The following Masters thesis performed within the WASCAL program seeks to screen for antibiotic resistant bacteria from commercially relevant fish species of the Cape Verde Islands. The impact of the stressors on fish health status will be determined by measuring anatomical, physiological and nutritional parameters, such as size, weight, organ intactness, among others. This Master’s thesis will be performed GEOMAR Helmholtz Centre for Ocean Research in Kiel.

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.