Quantification and localization of trace metals in natural plankton cells using a synchrotron x-ray fluorescence microprobe

B. S. Twining*, S. B. Baines, N. S. Fisher, C. Jacobsen, J. Maser

*Corresponding author for this work

Research output: Contribution to journalConference articlepeer-review

13 Scopus citations

Abstract

The accumulation of trace metals by planktonic protists influences the growth of primary producers, metal biogeochemical cycling, and metal bioaccumulation in aquatic food chains. Despite their importance, unequivocal measurements of trace element concentrations in individual plankton cells have not been possible to date. We have used the 2-ID-E side-branch hard x-ray microprobe at the Advanced Photon Source to measure trace elements in individual marine plankton cells. This microprobe employs zoneplate optics to produce the sub-micron spatial resolution and low background fluorescence required to produce trace element maps of planktonic protist cells ranging in size from 3 to >50 μm. We have developed preservation, rinsing, and mounting protocols that remove most of the salt from our marine samples, thus simplifying the identification of unknown cells and reducing high Cl-related background fluorescence. We have also developed spectral modeling techniques that account for the frequent overlap of adjacent fluorescence peaks and non-uniform detector response. Finally, we have used parallel soft x-ray transmission and epifluorescence microscopy images to estimate C normalized trace element concentrations, identify functional cell types (e.g., photosynthetic vs. non-photosynthetic), and correlate cell structures with spatial patterns in trace element fluorescence.

Original languageEnglish (US)
Pages (from-to)435-438
Number of pages4
JournalJournal De Physique. IV : JP
Volume104
DOIs
StatePublished - Jan 1 2003
Event7th International Conference on X-Ray Microscopy - Grenoble, France
Duration: Jul 28 2002Aug 2 2002

ASJC Scopus subject areas

  • Physics and Astronomy(all)

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