NERC GW4+ DTP PhD studentship: Ocean Viruses in Space and Time

University of Exeter - College of Life and Environmental Science

This project is one of a number that are in competition for funding from the NERC Great Western Four+ Doctoral Training Partnership (GW4+ DTP). At least 4 fully-funded studentships that encompass the breadth of earth and environmental sciences are being offered to start in September 2017 at Exeter. The studentships will provide funding for a stipend which is currently £14,296 per annum for 2016-2017, research costs and UK/EU tuition fees at Research Council UK rates for 42 months (3.5 years) for full-time students, pro rata for part-time students.

Oceanic processes are of major importance to global climate. Photosynthesis by marine phytoplankton produces almost as much oxygen and draws down almost as much carbon dioxide from the atmosphere as that performed by terrestrial plants. However, whereas much of the carbon on land is locked away in plants and soils, the vast majority of carbon in the oceans exists in a dissolved state (known as dissolved organic carbon, or DOC). A portion of DOC is rapidly consumed by the microbes that account for >90% of marine biomass, returning fixed carbon back to the atmosphere. The residence time of the remaining DOC can exceed 1000 years, making the oceans a vast sink for atmospheric carbon. Viruses infecting marine microbes are major contributors of the carbon cycle. Infections of up to 30% of bacterial standing stocks end in violent host death (lysis) (1), releasing a soup of DOC into the water for consumption by heterotrophs. Additionally, prior to lysis, viruses can radically reprogram host metabolism via auxiliary metabolic genes to favour production of more viruses, altering kinetics of nutrient uptake and cellular carbon outputs. Much of our current knowledge of marine virology and their impact on primary production relates to infection of phototrophs by the cyanophages. In comparison, our lack of knowledge of the impact of viruses on heterotrophy represents a major missing piece of the puzzle in global carbon biogeochemistry.

Dr Temperton is a collaborator in BIOS-SCOPE - an international, multi-disciplinary 5-year collaboration to investigate how microbial community interactions drive carbon biogeochemistry in open-ocean systems. As part of this project, we have collected samples for single-cell genomics and profiling of DOC composition across seasonal, depth and diel cycles from the Sargasso Sea, supported by metagenomic sampling and rich metabolomic metadata. The successful PhD student will collaborate with BIOS-SCOPE scientists to understand the impact of viruses on open-ocean carbon cycles. In particular, the research will focus on the newly discovered pelagiphages that infect the ubiquitous SAR11 clade (2). This group of bacteria comprises up to 50% of marine microbial communities. Their associated viruses are among the most abundant viruses on Earth, yet we know almost nothing about their impact on global carbon biogeochemistry. This project will integrate comparative genomics of viral sequences from single-cell genomes, seasonal infectivity profiles of SAR11 using epicPCR (3) and DOC profiles from the Bermuda Atlantic Time Series to investigate the scope and impact of SAR11 viral infection on marine carbon cycles. The composition of DOC produced by SAR11 viral infection and how this carbon is utilised by the microbial communities will be experimentally evaluated in laboratory and in fieldwork experiments in Bermuda by high-temperature catalytic oxidation (4).

The closing date for applications is midnight on 6 January 2017.

Please see http://www.exeter.ac.uk/studying/funding/award/?id=2273 for full details on how to apply.

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Type / Role:

PhD

Location(s):

South West England