PhD Studentship: Microbiome mediated resiliency of freshwater habitat

Freshwater is an important resource for humans as drinking and power supply (hydroelectric power stations), and as a source of irrigation, production and recreation. Regretfully, accessible freshwater accounts for only 0.01% of the land surface, making this resource limiting to both developed and developing countries. Moreover, use of water for household and production contaminate an already limited resource posing a threat to human and environmental health. Human impact represented by climate change (1), land use (2), use of plastics and microplastics (3) affects a large proportion of freshwater lakes and reservoirs worldwide. Public health risks associated with polluted water include increased carcinogenesis, immunodeficiency, lower cognitive performance and other behavioural deficits. Environmental health risk associated with polluted water includes decrease of ecosystem and recreational services as well as drastic reduction in biodiversity.

This project will, for the first time, investigate water organism resilience to common pollutants mediated by the microbiome. This is important because it is becoming increasingly apparent that the microbiome plays an important role in human and animal health. However, the effects of exposures to mixtures of pollutants on the microbiome, and in turn animal physiology and viability, are poorly understood.

Daphnia is the quintessential ecological model species central to the majority of standing freshwater habitats around the world and driver of ecosystem dynamics. Daphnia has a life cycle that alternates sexual recombination with asexual (clonal) reproduction enabling one to measure the response of the same genotype to multiple environmental stressors and their mixtures. Previous studies have shown that Daphnia is highly responsive to environmental change via both plastic and genetic responses (4, 5). Here, we will study the role of Daphnia gut microbiome in individual resilience to common pollutants and their mixtures. In addition, we will investigate whether microbiome transinfection from resistant to susceptible strains improves adaptive responses of natural populations to environmental mixtures of pollutants. The potential applications of these discoveries are far-reaching.

Objective 1: We will screen specimens of the keystone aquatic grazer Daphnia magna from natural environments to identify susceptible and resistant strains to common pollutants and their mixtures.

Objective 2: Using transcriptomics and life history trait assays we will measure the impact of pollutants and their mixtures on animal physiology and fitness. Using metagenomics we will assess the effect of pollutants and their mixtures on the microbiome of the same animals.

Objective 3. Using advanced computational tools and biostatistic approaches we will perform an integrative analysis of transcriptome, fitness and metagenome to uncover the mechanisms of resistance to pollutants and their mixtures.

Objective 4. From Objective 3 we will identify resistant strains in which response to pollutants (e.g. microplastics) is mediated by the microbiome. We will then perform transinfection experiments to assess whether transplanted microbiomes improve resistance to pollutants in susceptible strains.

Funding Notes

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 received the following financial support.

Annual stipend, set as £14,553 for 2017/18

Research training support grant (RTSG) of £8,000

CENTA students are required to undertake 45 days training throughout their PhD including a 10 day placement.

References

• A. A. Hoffmann, C. M. Sgro, Climate change and evolutionary adaptation. Nature 470, 479-485 (2011).
• J. A. Foley et al., Global consequences of land use. Science 309, 570-574 (2005).
• D. Eerkes-Medrano, R. C. Thompson, D. C. Aldridge, Microplastics in freshwater systems: A review of the emerging threats, identification of knowledge gaps and prioritisation of research needs. Water Research 75, 63-82 (2015).
• M. Cambronero Cuenca, B. Zeis, L. Orsini, Haemoglobin-mediated response to hyper-thermal stress in the keystone species Daphnia magna. Evolutioary Applications in press, (2017).
• L. Orsini, K. I. Spanier, L. De Meester, Genomic signature of natural and anthropogenic stress in wild populations of the waterflea Daphnia magna: validation in space, time and experimental evolution. Molecular Ecology 21, 2160–2175 (2012).