Origins, distribution, and ecological significance of marine microbial copper ligands
| dc.contributor.author | Nixon, Richard L. | |
| dc.contributor.supervisor | Ross, Andrew R.S. | |
| dc.contributor.supervisor | Nano, Francis E. | |
| dc.date.accessioned | 2020-09-01T06:13:16Z | |
| dc.date.available | 2020-09-01T06:13:16Z | |
| dc.date.copyright | 2020 | en_US |
| dc.date.issued | 2020-08-31 | |
| dc.degree.department | Department of Biochemistry and Microbiology | en_US |
| dc.degree.level | Doctor of Philosophy Ph.D. | en_US |
| dc.description.abstract | Copper (Cu) is required by marine microbes for essential biological processes, including photosynthesis and nitrogen fixation, but can be toxic above a certain threshold. Copper bioavailability in seawater is regulated by complexation with dissolved organic ligands of unknown source and structure. Culturing experiments have demonstrated the production of high-affinity Cu-binding ligands by marine algae in response to metal stress or limitation, suggesting they function either as metal ‘sponges’ to reduce copper toxicity or ‘carriers’ that promote uptake. The goal of my thesis research was to develop methods for the recovery and characterization of Cu ligands from seawater that could then be applied to natural samples to investigate sources and structures of recovered ligands. Using natural seawater spiked with model Cu ligands, I developed an immobilized Cu(II)-ion affinity chromatography (Cu(II)-IMAC) protocol which was shown to be effective in quantifying an operationally defined subset of natural Cu ligands. I then applied Cu(II)-IMAC to seawater collected along transects in the Canadian Arctic and NE Pacific Ocean to assess the abundance of this ligand pool across a diverse set of samples. Ligand distribution profiles and their covariance with other components of seawater (e.g. chlorophyll) were consistent with in situ biological production of some Cu-binding ligands. Model ligands spiked into seawater and recovered by Cu(II)-IMAC were also used to develop protocols for structural characterization of Cu ligands by solid-phase extraction (SPE) and tandem mass spectrometry (MS/MS). This research provides new tools for the isolation and characterization of copper ligands in natural samples, and new insights into the biogeochemical cycling and ecological significance of Cu in the ocean. | en_US |
| dc.description.scholarlevel | Graduate | en_US |
| dc.identifier.bibliographicCitation | Nixon, R. L., & Ross, A. R. S. (2016). Evaluation of immobilized metal-ion affinity chromatography and electrospray ionization tandem mass spectrometry for recovery and identification of copper(II)-binding ligands in seawater using the model ligand 8-hydroxyquinoline. Frontiers in Marine Science. https://doi.org/10.3389/fmars.2016.00246 | en_US |
| dc.identifier.bibliographicCitation | Nixon, R. L., Jackson, S. L., Cullen, J. T., & Ross, A. R. S. (2019). Distribution of copper-complexing ligands in Canadian Arctic waters as determined by immobilized copper(II)-ion affinity chromatography. Marine Chemistry. https://doi.org/10.1016/j.marchem.2019.103673 | en_US |
| dc.identifier.uri | http://hdl.handle.net/1828/12085 | |
| dc.language | English | eng |
| dc.language.iso | en | en_US |
| dc.rights | Available to the World Wide Web | en_US |
| dc.subject | copper | en_US |
| dc.subject | algae | en_US |
| dc.subject | marine biogeochemistry | en_US |
| dc.subject | metallophores | en_US |
| dc.subject | marine copper ligands | en_US |
| dc.subject | phytoplankton | en_US |
| dc.title | Origins, distribution, and ecological significance of marine microbial copper ligands | en_US |
| dc.type | Thesis | en_US |