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Contributed Talk 2: Long distance relationships between algae and bacteria

Thursday 27th November 2014 - 10:40 to 10:55
INI Seminar Room 1
Co-authors: F. Peaudecerf (Department of Applied Mathematics and Theoretical Physics (DAMTP), University of Cambridge), M. A. Bees (Department of Mathematics, University of York), R. E. Goldstein (Department of Applied Mathematics and Theoretical Physics (DAMTP), University of Cambridge), A. G. Smith (Department of Plant Sciences, University of Cambridge)

Microbial interactions are often predicated on metabolism: e.g. auxotrophs depend on nutrients made by other microbes. Many algae are vitamin auxotrophs, with several known species requiring exogenous vitamin B12 [1]. This vitamin must be obtained from bacteria, as only they can synthesise it. Laboratory experiments have demonstrated mutualistic interactions between bacteria and B12-dependent algae. Populations of the bacterium Mesorhizobium loti (B12 producer, carbon requirer) and the green alga Lobomonas rostrata (B12 requirer, carbon producer) in co-culture stabilise to an algae/bacteria ratio of 1/30, independent of initial inoculum ratio [2]. system [3].

Here we consider the interactions between microbial populations separated in space. Experiments on hard agarose indicate that mutualistic interactions exist at a distance. We present a mathematical model capturing the essence of these experiments: growing populations of algae and bacteria coupled by a diffusive channel. Solutions to the model reveal rich dynamics. We will discuss these and speculate on the ecological significance of our findings for understanding environmental biofilms and microbial mats.

[1] Croft, M. T. et al. Nature 483:90–93 (2005) [2] Kazamia, E. et al. Environ. Microbiol. 14, 1466 (2012)

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University of Cambridge Research Councils UK
    Clay Mathematics Institute London Mathematical Society NM Rothschild and Sons