The Dynamics of Freshwater Food Webs Under Multiple Threats

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Aquatic ecosystems around the world provide criticalservices to humanity including freshwater, food resourcesand the capacity to store carbon and thus mediate climatechange. Understanding how freshwater ecologicalcommunities respond to multiple simultaneous threatsincluding temperature changes, runoff from agriculture,invasive species and harvesting is critical to maintain theprovision of these services.This PhD will focus on a unique long-term dataset fromLake Windermere on species interactions across more thanProject Advertisementfour trophic levels and among 50+ species. The PhDproject aims to apply modern statistical modelling and foodweb modelling methods to derive deep understanding ofthe mechanisms driving resilience and resistance toenvironmental change, or the lack thereof, in freshwaterecosystems. In addition to the modelling, the PhD will alsoaim to fill critical data gaps in lower trophic levels includingphytoplankton and zooplankton functional groups.Specifically, the objectives of the PhD areObj1 - resolve functional groups, taxonomy and body sizein zooplankton and phytoplankton to help align with coreecological theory linking body size, metabolism, productionand foraging to biomass dynamics of species richcommunities.Obj2 - Applying modern statistical models (MultivariateAutoregressive models) to the time resolved Windermeredata, with a focus on trophic cascades, invasive specieseffects, climate change, contaminants. This objective offersa collaboration beyond Sheffield and CEH, including Dr.Stephanie Hampton from University of Washington, USA,an expert in these models.Obj 3 - Parameterise an established multi-trophic multi-species dynamical model across 5 trophic levels to explorewhether ecological theory can predict the kinds ofresponses seen in real time series to invasive species,temperature change and contaminants.Additional opportunities exist to extend the work to includethe microbial community and to explore shifts inecosystem function.The student will join an active research group usingstatistical and mathematical modelling using Julia and Rprorgramming languages to answer major questions abouthow multiple simultaneous threats to ecosystems impact onthe functions and services they provide. They will be part ofa supportive and productive lab in Sheffield and benefitfrom established relationships with the UK Centre forEcology and Hydrology and external partnerships. Thiscombination of training and research opportunities providesan excellent platform for reserach careers in and out ofacademia.