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The University of Southampton
Ocean and Earth Science, National Oceanography Centre Southampton

Research project: Molecular responses to metal stress at hydrothermal vents

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Hydrothermal vent support life in extreme abundance, yet these environments are highly enriched in many toxic compounds and metals compared with seawater. Metals catalyse the oxidation of sulphide, initialising a chain reaction that ultimately produces HO•, the most oxidising radical known to biological systems. The bulk of these reactive oxygen species (ROS) are absorbed by proteins, causing modifications to amino acid side chains. These changes can be reversible, temporarily protecting hey functional groups, or irreversible, inactivating key enzymes involved in detoxification.

Vent sites and HO radical production reaction
Vent sites and reaction

Adaptation to a vent environment

The origin of faunal colonisation of hydrothermal vents is poorly understood. Following large-scale ocean anoxic events, deep-sea vents may have been re-colonised by shallow-water fauna, adapting either directly or via gradual stepping stones to the high pressure, temperature, and chemical toxicity.

To understand how molecular mechanisms of detoxification may have evolved in vent fauna, it is important to compare their proteomic response to metal stress with that of a related non-vent species. My research focuses on two species of Mytillidae mussel; Bathymodiolus brevoir, and Mytilus edulis.

B. brevior were collected by ROV Kiel 6000 from two newly-discovered vent sites on the Southwest Indian Ridge (37oS, 2780 m). M. edulis, the shallow water blue mussel, were experimentally exposed to metal concentrations representative of a vent environment.

left: Metal exposure experiments with Mytilus edulis. Right: Hydrothermal vent-living Bathymodiolus brevior imaged on an active chimney on the Southwest Indian Ridge
Metal exposure experiments

Scientific Aims

My research aims to further the understanding of molecular mechanisms of detoxification in vent fauna, and to investigate the potential for pre-adaptation in non-vent, related species. Aims include:

  • Characterise the chemical and metal environment of hydrothermal vent habitats.
  • Measure metal accumulation in gill and digestive gland tissues.
  • Quantify key proteomic markers of oxidative stress such as thiol oxidation and carbonylation, using fluorescent labelling and Polyacrylamide Gel Electrophoresis (PAGE) techniques, in all tissues.
  • Generate protein expression profiles and contextualise these with detoxification pathways.

 

Example of reversible & irreversible oxidative modifactions to an amino acid thiol (-SH) group (Sheehan, 2006)
Oxidative modification reaction

Key Contacts

Catherine Cole (Postgraduate research student)

Dr Rachael James (Supervisor)

Dr Doug Connelly (Supervisor)

Prof. David Sheehan (Collaborator)

PhDs and Other Opportunities

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Associated research themes

Hydrothermal Processes and Mineral Deposits

Geochemical Ecology

Related research groups

Geochemistry
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