Specialism: Marine Biochemistry
Trace metal biogeochemistry
I investigate the distribution of metals in the marine environment and am particularly interested in interactions between organisms and metals. I am currently undertaking research into the way organisms optimise their use and acquisition of iron in the ocean. Iron is an important metal in the marine environment as it limits productivity in approximately 30% of the surface ocean. Specific research projects in this area involve the investigation of bioinorganic iron complexes such as hemes and siderophores. I also work on metal toxicity, investigating the production of compounds (phytochelatins) that maintain trace metal homeostasis in phytoplankton and may thus represent useful biomarkers in contaminated systems.
Hemes in marine bacterioplankton and particulate material
I am pioneering research on hemes in the marine environment. Hemes are intracellular iron containing porphyrins, which make up approximately 40 % of the total iron pool of organisms. Hemes play a critical role in both photosynthesis and respiration, yet despite this little is known about heme levels in marine organisms or their response to variations in ambient iron concentrations. In my lab we are investigating hemes in order to assess their suitability as an indicator of "aneamia" in marine phytoplankton and bacteria, and as an indicator for biological particulate iron in the ocean.
Detection, characterisation and biogeochemistry of iron chelators in seawater
The extent to which organisms take up metals from seawater is known to be affected by metal speciation. Some metals are reduced in availability by complexation with organic matter, while in some cases organic complexants may be released by organisms to increase availability. I am particularly interested in siderophores, high affinity iron chelators used by bacteria to acquire iron in low iron environments. In my lab we develop novel, sensitive and specific techniques using liquid chromatography – mass spectrometry with which to separate, detect and quantify siderophores in seawater.
Other research interests
Other research interests include interactions between marine phytoplankton viruses, their phytoplankton hosts and trace metals. I have also worked on the distribution of amino acids in the dissolved and particulate phase in seawater.
David J. Honey
Khairul Bin Mohamed
Dr Martha Gledhill
Ocean and Earth Science, National Oceanography Centre Southampton University of Southampton Waterfront Campus European Way Southampton SO14 3ZH United Kingdom
Room Number: NOCS/184-11
Telephone: (023) 8059 9258
Dr Martha Gledhill's
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