Fate of coloured dissolved organic matter in the ocean

University Supervisor: Prof. Richard Evershed (University of Bristol)
Background: The global ocean reservoir of dissolved organic matter (DOM)
contains approximately 685 x 1015 g C, which is equivalent to the
atmospheric carbon pool and represents the second largest pool of carbon
in the world. Understanding the bio-availability and transformation of DOM is
essential to our knowledge of the effects of climate change on ocean
carbon. The coloured component of DOM (CDOM) is a complex mixture of
organic molecules some of which are a substrate for microbial growth.
Sunlight-induced reactions leading to CDOM breakdown (photobleaching),
can release organic nutrients which can enhance microbial growth and
climate-active-gases such as carbon dioxide (CO2) and carbon monoxide
(CO). Considerable uncertainty remains over the composition of CDOM in
the global ocean and which of these components are used by bacteria and
which are released as gases. Fluorescence Excitation Emission
spectroscopy coupled with Parallel Factorial (PARAFAC) is a powerful
technique for studying the composition of the CDOM in the ocean. It p
rovides a chemical fingerprint of active fluorescent humic and proteinaceous
fractions and combined with the measurement of optical properties of
CDOM, can be used to trace the fate and environmental significance of
DOM in carbon cycle.
The successful PhD student will undertake a unique programme of research
by developing and exploiting these techniques on research cruises that
cross the Atlantic Ocean from the UK to the Falkland Islands on the Atlantic
Meridional Transect (AMT; http://www.amt-uk.org/) which is co-ordinated by
PML. The cross-disciplinary nature of this research means that the student
will develop expertise in:
• Sea going oceanography
• Chemical and optical analytical techniques
• Open ocean biogeochemistry
• Impact of organic carbon on climate relevant gases
• Numerical and statistical data analysis
They will work in a world class research institutes where they will make use
of state-of-the-art field, laboratory, computing and instrumentation facilities
available across both institutions and have opportunities to present their
work at international conferences. The student should have obtained at least
a 2i BSc in environmental, biological, chemical or marine sciences or related
field and who can work independently and collaboratively at sea.