All in the timing: the importance of timing of root growth and activity in capturing nutrients in natural ecosystems.

Supervisors: Dr Gareth K Phoenix and Dr Duncan D Cameron

Key words: Plant nutrient uptake, ecology, ecophysiology, phenology, plant growth

Nutrient availability in soils changes considerably throughout the year, but peaks in availability may not coincide with peaks in plant growth or the activity of roots and mycorrhizae that capture the nutrients. In fact, in some species (such as Arctic shrubs), new root growth can occur at the end of the summer, missing the peak in spring soil nutrients entirely. This raises important questions as to how the timing of root growth and activity can influence plant nutrient capture, why different species show contrasting timing in root growth and activity, and the importance of autumn-produced roots that survive winter in nutrient uptake the following spring. Such questions are also critical for understanding the impacts of climate change since warmer springs may mean earlier peaks in nutrient availability, but it remains unclear whether plants compensate by changing their timing of root growth, or whether nutrient availability and root activity become more asynchronous.

This PhD will investigate the importance of timing of root and mycorrhizal growth and activity in capturing nutrients, the consequences of asynchrony with nutrient availability and the effects of climate warming. It will use a combination of laboratory, growth chamber and field studies. Field work will focus on UK ecosystems with opportunity to expand the study into Arctic tundra.

The project would suit a highly motivated, independently thinking student with a background in/enthusiasm for plant ecology/biology, plant nutrient acquisition and the impacts of climate change. The project will include use of radio-isotope P compounds – full training will be given.

To apply, please complete an online application form which can be found at www.shef.ac.uk/postgraduate/research/apply/applying
The closing date is 15th January 2013