Salinity-dependent diatom biosilicification implies an important role of external ionic strength

Engel G. Vrieling*, Qianyao Sun, Mingwen Tian, Patricia J. Kooyman, Winfried W. C. Gieskes, Rutger A. van Santen, Nico A. J. M. Sommerdijk

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

69 Citations (Scopus)

Abstract

The role of external ionic strength in diatom biosilica formation was assessed by monitoring the nanostructural changes in the biosilica of the two marine diatom species Thalassiosira punctigera and Thalassiosira weissflogii that was obtained from cultures grown at two distinct salinities. Using physicochemical methods, we found that at lower salinity the specific surface area, the fractal dimensions, and the size of mesopores present in the biosilica decreased. Diatom biosilica appears to be denser at the lower salinity that was applied. This phenomenon can be explained by assuming aggregation of smaller coalescing silica particles inside the silica deposition vesicle, which would be in line with principles in silica chemistry. Apparently, external ionic strength has an important effect on diatom biosilica formation, making it tempting to propose that uptake of silicic acid and other external ions may take place simultaneously. Uptake and transport of reactants in the proximity of the expanding silica deposition vesicle, by (macro)pinocytosis, are more likely than intracellular stabilization and transport of silica precursors at the high concentrations that are necessary for the formation of the siliceous frustule components.

Original languageEnglish
Pages (from-to)10441-10446
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Volume104
Issue number25
DOIs
Publication statusPublished - 19-Jun-2007

Keywords

  • biosilica
  • silica nanostructure
  • silicification
  • silica chemistry
  • THALASSIOSIRA-PSEUDONANA BACILLARIOPHYCEAE
  • ATOMIC-FORCE MICROSCOPE
  • NANOSTRUCTURED SILICA
  • WALL MORPHOGENESIS
  • NAVICULA-SALINARUM
  • CELL-CYCLE
  • GROWTH
  • DEPOSITION
  • MODEL
  • BIOMINERALIZATION

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