PhD Research Project: NERC CENTA - The biology of suspended animation and resilience to environment
Daphnia represent sentinel species in assessing the health of freshwater systems, and are key indicators of ecosystem resilience to environmental change1. Fundamental to their survival is being able to enter a specialised dormant state, termed diapause, to avoid unfavourable conditions. Seasonal changes in many environmental factors (light, temperature, food availability etc.) program the diapause response, and this shifts populations from a cycle of asexual reproduction to the sexual production of diapausing eggs (Fig. 1)2. This switch plays a fundamental role in regulating Daphnia phenology, in turn influencing freshwater food webs and nutrient cycling. While most diapausing embryos resume development the following spring, some do not and can remain viable in lake sediments for hundreds of years 3.
This provides a unique window into examining the ecology of historic populations (resurrection ecology4), as well as understanding what biological processes enable such prolonged periods of suspended animation. Through our ongoing work with the Daphnia Genomics Consortium (DGC), Daphnia is emerging as one of the best characterized genomic systems5, yet we currently know almost nothing about the molecular mechanisms underpinning Daphnia diapause, including how they cope with environmental stresses during dormancy. Yet this information is critical to modelling the impact of continued environmental change on freshwater systems.
Core objectives of the project are:
i) Provide the first molecular characterisation of diapause in Daphnia using both ‘omic and systems biology approaches; ii) Quantify the stress tolerance limits of diapausing embryos to determine tipping points in population survival. iii) Determine how the decision to enter diapause is affected by increased pollution and climate change.
In addition to completing an online application form, you will also need to complete and submit the CENTA studentship application form available from www.centa.org.uk.
CENTA studentships are for 3.5 years and are funded by the Natural Environment Research Council (NERC). In addition to the full payment of their tuition fees, successful candidates will receive the following financial support.
Annual stipend, set at £14,296 for 2016/17
Research training support grant (RTSG) of £8,000
CENTA students are required to undertake from 45 days training throughout their PhD including a 10 day placement.
1. Eads et al. (2008) Ecological genomics in Daphnia: stress responses and environmental sex determination. Heredity 100: 184-190.
2. Milner, et al. (2011) Linking genes to communities and ecosystems: Daphnia as an ecogenomic model. Proc. Roy. Soc. B. doi:10.1098/rspb.2011.2404.
3. Frisch et al. (2015) A millennial-scale chronicle of evolutionary responses to cultural eutrophication in Daphnia. Ecol. Lett. 17: 360-368.
4. Orsini et al.(2013) The evolutionary time machine: using dormant propagules to forecast how populations can adapt to changing environments. TREE 28: 274-282.
5. Colbourne J. K et al (2011) The Ecoresponsive Genome of Daphnia pulex. Science 331: 555-561.
6. Ebert D. Ecology, Epidemiology, and Evolution of Parasitism in Daphnia [Internet]. Bethesda (MD): National Center for Biotechnology Information (US); 2005. Chapter 2, Introduction to Daphnia Biology. Available from: http://www.ncbi.nlm.nih.gov/books/NBK2042/.