Carbon cycling in the sub-surface environment of Enceladus
Lead Research Organisation:
The Open University
Department Name: Faculty of Sci, Tech, Eng & Maths (STEM)
Abstract
Organic molecules are the building blocks of life, ubiquitous throughout the cosmos. Although abiotic formation processes dominate, the search for organic biomarkers as indicators of life has driven the development of instrumentation for many life detection missions.
Simple organic species, such as methane, have been detected within the gas and ice plumes from Enceladus [1]. With the origin of these plumes believed to be deep beneath the satellite's ice layer, potentially from a sub-surface ocean environment [2], determining the origin of these organic species (or precursor carbon) has become the aim of many studies.
Modelling of the Enceladus interior suggest that its silicate composition is akin to other Solar System carbonaceous bodies [3, 4]. Organic material may be sourced from here, liberated via aqueous processing of the silicate, and may reach the ice surface by convection processes or cryovolcanism [5]. Investigations into plausible geochemical processes operating in this environment have, to date, been limited to, or focussed on, investigating discrete reaction pathways [e.g. 6, 7].
Despite this possible abiotic origin for these molecules, the existence of a microbial community in the sub-surface ocean presents an exciting viable alternative source. Although the factors influencing the existence of life are numerous, determining whether microorganisms can utilise, or are inhibited by, liberated carbon species is an important factor in establishing whether the Enceladus sub-surface ocean is a plausible target for future life detection missions.
Research questions
-To what extent are organic, and other carbon bearing species, liberated from Enceladus' silicate interior?
- What influence does this have on geochemical cycling?
- Do these species support or inhibit microbial life?
Methodology
This project would utilise a newly-funded, high pressure reactor to simulate the sub-surface conditions on Enceladus, using silicate analogues and invoking likely environmental conditions (derived from the results of published modelling data).Analysis of the substrate and fluid would utilise the state of the art analytical techniques at the OU (GC-MS, HPLC, Py-GC-MS). To determine the influence of liberated organic species on geochemical cycling, thermochemical modelling, using codes such as SOLMINEQ88, that introduces organic molecules, will be utilised. The anaerobic microbiology facilities will be used to investigate the impact of liberated organic molecules on microbes.
Simple organic species, such as methane, have been detected within the gas and ice plumes from Enceladus [1]. With the origin of these plumes believed to be deep beneath the satellite's ice layer, potentially from a sub-surface ocean environment [2], determining the origin of these organic species (or precursor carbon) has become the aim of many studies.
Modelling of the Enceladus interior suggest that its silicate composition is akin to other Solar System carbonaceous bodies [3, 4]. Organic material may be sourced from here, liberated via aqueous processing of the silicate, and may reach the ice surface by convection processes or cryovolcanism [5]. Investigations into plausible geochemical processes operating in this environment have, to date, been limited to, or focussed on, investigating discrete reaction pathways [e.g. 6, 7].
Despite this possible abiotic origin for these molecules, the existence of a microbial community in the sub-surface ocean presents an exciting viable alternative source. Although the factors influencing the existence of life are numerous, determining whether microorganisms can utilise, or are inhibited by, liberated carbon species is an important factor in establishing whether the Enceladus sub-surface ocean is a plausible target for future life detection missions.
Research questions
-To what extent are organic, and other carbon bearing species, liberated from Enceladus' silicate interior?
- What influence does this have on geochemical cycling?
- Do these species support or inhibit microbial life?
Methodology
This project would utilise a newly-funded, high pressure reactor to simulate the sub-surface conditions on Enceladus, using silicate analogues and invoking likely environmental conditions (derived from the results of published modelling data).Analysis of the substrate and fluid would utilise the state of the art analytical techniques at the OU (GC-MS, HPLC, Py-GC-MS). To determine the influence of liberated organic species on geochemical cycling, thermochemical modelling, using codes such as SOLMINEQ88, that introduces organic molecules, will be utilised. The anaerobic microbiology facilities will be used to investigate the impact of liberated organic molecules on microbes.
Organisations
People |
ORCID iD |
| Victoria Pearson (Primary Supervisor) | |
| Rachael Hamp (Student) |