- Novel research to describe forest nitrogen cycle dynamics in response to global change.
- Access to one of the most extensively characterised ancient woodlands in the UK, facilitating opportunities for wider collaboration in forest ecology research.
- A blend of laboratory and field experience, accessing skills ranging from molecular techniques to field measurements of trace gases.
Temperate forests are currently experiencing rapid alteration owing to global change pressure such as elevated CO2, unpredictable weather patterns, and atmospheric deposition (Fei et al. 2017; Jo et al. 2019). While it is well-known that such changes affect the organisms that inhabit forests and woodlands, the degree to which such changes affect forest functioning is largely unknown (Clark et al. 2016). Forests perform numerous functions, perhaps none more critical than retaining nutrients and exchanging climate-active gases with the atmosphere. As such, changing forest composition has the potential to affect both air and water quality, as well as feedbacks to the climate system. However, we do not yet know whether those changes will be positive (amplifying) or negative (mitigating).
The overarching objectives of this project are to (i) define how dominant tree species, and the effect of global change processes on those species, influence nitrogen cycling in forest soils and (ii) explore the applicability of trait-based framework(s), such as the Mycorrhizal Associated Nutrient Economy hypothesis (Phillips et al 2013; Mushinski et al. 2019, 2021), to predict the consequences of forest community change. The project will utilise a combination of field studies, environmental chamber experiments, laboratory mesocosms, molecular microbiology, and ecosystem models to accomplish these objectives. We will leverage an extensively characterised ancient woodland (Wytham Woods) to facilitate the collection of high-resolution data in situ and from laboratory mesocosms.
The student and PI will collaboratively define the specific research direction of the project. Potential lines of inquiry include:
(1) Linking aboveground community composition to nitrogen gas emissions from plots differing in the relative abundance of trees that associate with various groups of root symbionts and underlying soil characteristics;
(2) Determining forest soil nitrogen cycle sensitivity to elevated CO2, drought, water logging, and nitrogen deposition;
(3) Developing statistical models of species-soil-climate relationships to produce maps of future forest composition that can be coupled to process-based biogeochemical models – allowing us to predict the consequences of shifts in forest community composition in the wake of global change.
HostUniversity of Warwick
- Climate and Environmental Sustainability
- Organisms and Ecosystems
Please note that exact protocols will be defined at the onset of the project. We will make seasonal nitrogen flux measurements as well as evaluate the soil microbial community in forest plots at Wytham Woods. To assess the impact of tree species and global change drivers on nitrogen fluxes, we will grow saplings of tree species known to associate with differing microbial symbionts in laboratory mesocosms. Flux values gathered from in situ and ex situ experiments will be used to parameterise ecosystem models, facilitating predictions of forest community change.
Training and skills
Training during this fellowship includes a wide range of molecular techniques and analyses (microbial culturing, DNA extraction from soil, PCR, sequencing, and bioinformatics) as well as analytical chemistry (nitrogen oxide quantification, reactive oxygen extraction from soil and subsequent quantification, and building sampling mesocosms). Field-based sampling and measurements from forest ecosystems will also be emphasized.
Partners and collaboration
Dr. Mushinski leads the Environmental Processes Laboratory (SLS-Warwick). His research group studies nitrogen cycle biogeochemistry and soil-microbe interactions in a range of natural and manged ecosystems. Professor Bending leads the Microbial Ecology Laboratory (SLS-Warwick), where his group studies the structure, diversity and function of microbial communities inhabiting plants, soil, and water – often integrating a variety of ‘omics approaches. Professor Malhi leads the Ecosystem Dynamics Laboratory at Oxford and is Principal Scientist for the Wytham Woods ForestGEO plot. Mushinski and Bending will be the primary advisors for the project, while Malhi will facilitate access to Wytham Woods.
If you would like to apply to the project please visit: https://warwick.ac.uk/fac/sci/lifesci/study/pgr/studentships/nerccenta/
Define experimental design. Conduct field sampling – measuring nitrogen fluxes from forest soils at Wytham Woods.
Assess how individual tree species influence the production or suppression of nitrogen fluxes in response to global change. Define how plant, soil, and microbial characteristics influences fluxes.
Utilise ecosystem models and Earth observation data to define how forest community change may influence nitrogen cycle feedbacks.
Clark, J. S. et al. 2016. The impacts of increasing drought on forest dynamics, structure, and biodiversity in the United States. Global Change Biology 22: 2329-2352.
Fei, S. et al. 2017. Divergence of species response to climate change. Science Advances 3: e1603055.
Jo, I. et al. 2019. Shifts in dominant tree mycorrhizal associations in response to anthropogenic impacts. Science Advances 5: eaav6358.
Mushinski, R.M. et al. 2019. Microbial mechanisms and ecosystem flux estimation for aerobic NOy emissions from deciduous forest soils. Proceedings of the National Academy of Sciences, USA 116: 2138-2145.
Mushinski, R.M. et al. 2021. Nitrogen cycling microbiomes are structured by plant mycorrhizal associations with consequences for nitrogen oxide fluxes in forests. Global Change Biology 27: 1068-1082.
Phillips, R.P. et al. 2013. The mycorrhizal-associated nutrient economy: a new framework for predicting carbon–nutrient couplings in temperate forests. New Phytologist 199: 41-51.
The School of Life Science at the University of Warwick has SOP’s in place to allow research to continue in light of COVID-19. This includes reducing the capacity of people in laboratory spaces, placing protective barriers between workstations, and working from home when possible. The laboratory portion of this work will proceed as normal, within the scope of the SOP’s. All meetings associated with this project will be in line with current guidelines. The field component will proceed within the confines of a subsequent SOP – to be developed between the PI in accordance with all University- and government-mandated requirements.