Dr Damian Rivett, postdoctoral researcher
Functional redundancy in bacterial communities
Bacterial communities are incredibly diverse, with thousands of different taxa in every drop of water. It seems inconceivable that every one of these taxa is performing a different ecological role. The conventional wisdom in the microbiological literature is therefore that most bacteria are functionally redundant, so the loss of many species from the community would be unlikely to effect functional matter for rates of nutrient cycling, decomposition, and other ecosystem functions. The project is trying estimate the degree of functional redundancy in naturally-occurring bacterial communities. He is developing methods for estimating interactions among bacterial taxa embedded within complex communities using an archive of hundreds of intact bacterial communities collected from water-filled tree holes.
|Dr Tom Vogwill, postdoctoral researcher
Functional redundancy in bacterial community II
The work will complement ongoing research in the lab investigating the role and importance of functional redundancy in bacterial communities.
|Dr Tom Scheuerl, postdoctoral researcher
Adaptation in diverse communities
Many studies have experimentally modified the environment and tracked how microbes evolve to the new conditions, for example in response to antibiotics. However, almost all of these experimental studies have been performed in the lab with just a single focal species. We know that interactions among species are fundamentally important for how they respond to changing environmental conditions. The project is therefore investigating how adaptation to novel conditions is affected by the surrounding biotic community. He has developed experimental methods for tracking adaptation in focal species embedded within complex communities by ‘caging’ them in dialysis bags. The research is part of a NERC-funded grant with Tim Barraclough.
|Dr Maaike van Agtmaal, postdoctoral researcher
Role of soil bacterial biodiversity in response to land use intensification
There is little understanding of how soil microbial communities contribute to soil functioning. This is surprising since ‘healthy’ soils are vital for agriculture. We are looking at how microbial diversity affects soil functional processes, and how this relationship is altered by land use intensification. The project is part of the U-GRASS consortium lead by Rob Griffiths investigating the impacts of land use intensity on belowground microbial communities.
|Sarah Pierce, PhD candidate
Above-belowground interactions under global change
Changing environmental conditions in southern England are expected to result in rainfall patterns that are more variable and more extreme (heavy rain or long periods of drought). The project experimentally mimicked these effects in a long-term, large-scale field experiment that modulated rainfall patterns in experimental plots, and compare the result in plant communities across a gradient of plant functional diversity. Results are framed in terms of their effect on above-ground productivity, functional properties (e.g. net ecosystem respiration), and soil microbial community composition.
|Shorok Mombrikotb, PhD candidate (Rob Griffiths, co-supervisor)
Response of soil bacterial communities to abiotic drivers
There has been much work correlating soil microbial communities with common abiotic factors. This work has confirmed pH as being a key factor, along with a number of subsidiary factors such as the ratio of carbon to nitrogen. However, there are few field-scale experimental manipulations that link cause and effect, and even fewer that have been conducted over multiple years. The project makes use of a long term (~25 year) field experiment set up by Mick Crawley to investigate the role of key abiotic drivers in soil environments, including pH, nutrients, pesticides, and rabbit grazing.
|Claire Bankier, PhD candidate (Andrew Singer, co-supervisor)
Experimental coevolution of phage-bacteria interactions in nature
Viruses are important pathogens of bacteria in many environments, and can be responsible for a large proportion of bacterial mortality. There is a large literature looking at coevolution between bacteria and the viruses that infect them (bacteriophage), but most of studies have been based on surveys, and it is difficult to track coevolution from observational data alone. An alternative is to use experimental evolution. The major advantage of this approach is that it is possible to track coevolution using ‘time shift’ experiments, where ancestral bacteria can be assayed against future phage and vice versa. However, virtually all of these experiments have been conducted in very artificial laboratory conditions. The project introduces some of the complexities of natural systems by performing experimental coevolution in the presence of a complex community and under a variety of abiotic conditions.
|Drew Wilson, PhD candidate
Bacterial interactions in space
There is a widely-held idea in microbial ecology that “everything is everywhere, but the environment select”. This idea has a lot of support: most microbes have the capacity to disperse anywhere on Earth, and the enormous diversity of microbes at any particular location often means that finding a particular microbe at a particular location is simply a matter of looking hard enough. However, the increased capacity to identify taxa using molecular techniques has shown that there is in fact considerable heterogeneity in spatial distributions. Surveys and experiments have shown spatial organisation at the scale of countries, and at the scale of micrometers. The project is looking at how small-scale dispersal influences the alpha and beta diversity of microbial communities using a microcosm system where microbes migrate among patches.
|Matt Jones, PhD candidate
Factors affecting invasion success in bacterial communities
When a bacterial cell arrives in a new environment, it is faced with formidable obstacles to its integration. The foreign habitat is likely to be different to the one in which the newcomer evolved, and full of species adapted to both it and one another. Nonetheless, microbes do invade new environments and with profound consequences – pathological infection of new hosts, contamination of water sources and successful probiotic treatments, to name but a few. This project aims to understand the development of obstacles to invasion and the bacteria that overcome them, with particular attention to the interacting effects of community composition, size and evolution.
|Eric Topham, PhD candidate (Owen Lewis, David Bass co-supervisors)
Functional diversity in bacteriovorous protists
Protists are important bacterial predators in most environments, but much of their diversity is cryptic. DNA sequencing has revealed a high levels of diversity hidden behind apparently identical morphologies. We are interested in how diversity of protist species is maintained in natural environments, and in how this diversity impacts bacterial communities. Since the natural history and ecology of most protist species is completely unknown, the project is looking to find new ways of defining functional groups of protists, and is using this information to predict the dynamics and diversity of protist communities.
|Tom Smith, PhD candidate (primary supervisor Samraat Pawar)
Bacterial responses to temperature
The project will aim to understand how bacteria isolated from natural environments are affected by changing temperature regimes.
|Alessandra Dupont, PhD candidate (David Bass primary supervisor)
Causes and consequences of protist diversity
|Victoria Burton, PhD candidate (Andy Purvis primary supervisor)
Response of soil and litter communities to land use change
|Meirion Hopkins, Technician
|Dr Ville Friman, Imperial Junior Research Fellow|
|Dr Katja Lehmann, PhD candidate|