Dr China Hanson
Lecturer in Molecular Microbial Ecology
Email: email@example.comTelephone: +44 (0)20 7882 3089Room Number: Room 5.10, Fogg building
Microbial Diversity and Biogeography
Microbes are the most abundant and diverse organisms on Earth. They inhabit every known environment from the deep oceans to the atmosphere to every nook and cranny of the human body! How is such enormous diversity generated and maintained in nature? And why is it important?
To test aspects of these broader questions, I strive for an experimental approach using a variety of microbial model systems backed by observational studies of natural systems. My perspective is unique because it is strongly underpinned by classic ecology and evolutionary theory while at the same time depends on a range of methodological tools from the most advanced state-of-the-art molecular and “omics” technologies to old-school microbiological culturing techniques.
Currently, my research has three interrelated themes:
- The role of viruses in shaping the diversity and function of microbes
The seas are full of viruses – 50 million viruses in a single teaspoon of seawater! But these are not the kind that make us, or even marine animals, sick. The vast majority of these viruses infect tiny microscopic organisms - bacteria and small eukaryotes. In fact, viruses that infect bacteria, known as phages, are the most numerous biological entities on Earth and harbour an astonishing amount of uncharacterised genetic diversity. This suggests that these viruses are successful agents of infection and therefore ecologically important, yet little is known about virus-microbe interactions in natural systems. We aim to use marine virus-microbe model systems, mesocosm experiments, genomics and other cutting-edge molecular tools to elucidate relationships between virus activity, host diversity, and marine biogeochemical cycling.
- Dispersal and biogeography in the marine deep biosphere
Deep below the surface of the Earth exists an entirely microbial world! The extreme conditions here – dark, very low energy, no oxygen, and extreme temperature and pressure – have resulted in unique microbial diversity and ecosystems. Our understanding of these microbially-dominated ecosystems is hindered by the fact that the subsurface is extremely difficult to sample directly. Thermophilc (heat-loving) sulphate-reducing bacteria derived from warm deep biosphere sources are found as dormant endospores in cold marine sediments, where they have little hope of growing. How did these “thermospores” get there and why are they there? Answers to these questions can serve as a unique window into the ecology and evolution of microbes in the difficult-to-sample deep biosphere. Our current approach involves quantifying the dispersal and biogeography of thermospores from Arctic marine sediments.
- The processes responsible for microbial biogeographic distributions
In recent years, microbial biogeography has become much more than “everything is everywhere, the environment selects.” Like all organisms, microbial diversity in space and time is ultimately structured by four basic processes - selection, dispersal, drift, and mutation. While current evidence agrees that selection is undeniably important, the significance of the other three processes for microbial biogeography remains highly debated. We aim to directly test the relative influence and outcome of these processes by using manipulative experiments followed by sequencing and high-resolution bioinformatic analysis. Understanding the mechanisms contributing to microbial biodiversity and biogeography can ultimately lead to better predictions of ecosystem response to change.