Project proposal details

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Project title
The scaling of metabolism with mass in prokaryotes
Contact name
Samraat Pawar
Project based at
Silwood Park (Imperial)
Imperial contact email
Project description
A major accepted "law" in ecology is that metabolic rate scales with body size (Kleiber's law, Kleiber 1932). In metazoa, metabolic rate increases with body mass with a 3/4 scaling factor, however this power law may be different across other major evolutionary groups (DeLong 2010). Interestingly, recent work (Kremer 2017) seems to show mass scaling relationships in Cyanobacteria departing from previously reported mass scaling across prokaryotes (bacteria and archaea) in general. Are mass scaling laws really universal across major domains of life, or do they differ amongst taxonomic or functional groups (e.g. heterotrophs/autotrophs)? You will test these scaling relationships using our lab's database of microbial growth rates which you will first add to by scanning the literature for microbial cell size information. You will then calculate mass:growth rate scaling relationships across different levels of taxonomic and functional organisation, incorporating temperature normalisation through fitting thermal performance curves for each species. Various models of organism or population rates incorporate mass scaling terms (usually constrained to 0.75), thus understanding the universality of mass scaling relationships is important for better refinement of such modelling work.

1. Kleiber (1932) "Body size and metabolism." Hilgardia

2. DeLong et. al. (2010) "Shifts in metabolic scaling, production, and efficiency across major evolutionary transitions of life." PNAS

3. Kremer et. al. (2017) "Temperature- and size-scaling of phytoplankton population growth rates: Reconciling the Eppley curve and the metabolic theory of ecology." Limnology and Oceanography

Further reading

Brown et. al. (2004) "Toward a metabolic theory of ecology." Ecology

Uyeda et. a. (2017) "The Evolution of Energetic Scaling across the Vertebrate Tree of Life." The American Naturalist

GarcĂ­a et. al. (2016) "The allometry of the smallest: superlinear scaling of microbial metabolic rates in the Atlantic Ocean." The ISME Journal
Additional requirements
Ability to program/code in R, Python, or equivalent, and willingness to love our unicellular relatives!
Available support
Desk space, computing resources
Date uploaded

Project proposal limitations

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Project length limitations
5 months, 9 months
Available date limitations
Autumn (Sept-Oct), Winter (January), Spring (April-May)
Suitable for
Ecology Evolution and Conservation, Computational Methods in Ecology and Evolution (MSc), Computational Methods in Ecology and Evolution (MRes), Ecological Applications, Ecosystem and Environmental Change MRes