Coccolithophore Speciation and Adaptation in the Quaternary Oceans

Adaptation and speciation processes are considered to have worked in rather different ways between small sub-populations of terrestrial organisms (1,2) and vastly large populations of abundant marine microplankton. In the relatively homogenous open oceans, where no apparent physical barrier to gene flow exists to patently promote the allopatric speciation scenario, speciation processes are further obfuscated and it is still unclear how new plankton species originate and evolve (e.g. 3,4). Sympatric speciation, which has been generally assumed to be less likely than allopatric speciation, is considered to occur -especially in the marine realm- when populations of a species that share the same environment become reproductively isolated from each other without any geographical barrier being present.The scenario of sympatric speciation has been a key aspect of evolution in the marine realm and noted by few studies (e.g. 5,6) indicating that some species may have indeed formed in sympatry with occasional hybridisation between them. This mode of speciation though, has been poorly understood and hotly debated because of a) the large populations of planktonic microorganisms in relatively homogeneous habitats, b) their high dispersal potential over geographic areas and c) the apparent lack of strong barriers in open oceanic environments.
The primary scientific aim of this project is to shed light on the macro- and micro-evolutionary processes driving plankton speciation, especially in diverse lineages. Evolutionary patterns can be quite traceable in marine sediments in extraordinary detail but have also been accrued to some extent in the physiology and genomes of the modern organisms. The benefit of this research is that a combined contextual analysis of fossil record and genome sequence data will be established and whether any relationship between species radiations and extinctions throughout the Quaternary can be established. This will ultimately lead to a myriad of potential end users from evolutionary biologists, biogeochemists, micropalaeontologists, (palaeo)climate modellers and the exploration industry. Further aims of this study should include:
1To determine how sympatric evolution works in the modern oceanic realm and how do plankton species separate from one another.
2To probe if morphological change adapts well to the biogeochemical characteristics of the Quaternary calcareous nannoplankton communities.
3To determine whether there are any diversification and extinction patterns that may be recurrent throughout the Quaternary.
4To investigate where the hotspots of plankton biodiversity were situated and if/how they have been displaced due to climate change.