Diatoms response to salinity changes: investigations using single pulse and cross polarisation magic angle spinning 29Si NMR spectra

M R Johnston; J R Gascooke; A V Ellis; S C Leterme

doi:10.1039/c8an00948a

Diatoms response to salinity changes: investigations using single pulse and cross polarisation magic angle spinning ²⁹Si NMR spectra

Analyst. 2018 Oct 8;143(20):4930-4935. doi: 10.1039/c8an00948a.

Authors

M R Johnston¹, J R Gascooke, A V Ellis, S C Leterme

Affiliation

¹ Flinders Institute for Nanoscale Science and Technology, Flinders University, College of Science and Engineering, GPO Box 2100 Adelaide, South Australia 5001, Australia. Martin.Johnston@flinders.edu.au.

PMID: 30198522
DOI: 10.1039/c8an00948a

Abstract

Diatoms Thalassiosira pseudonana and Chaetoceros muelleri (Bacillariophyceae) were cultured at three different salinities (26, 36 and 46 practical salinity units (PSU)) and their silica content examined using natural abundance 29Si magic angle spinning (MAS) nuclear magnetic resonance (NMR) spectroscopy. The samples were investigated using both single pulse (SP) and cross-polarisation (CP) MAS experiments. In addition, samples of T. pseudonana were examined using variable contact time CP MAS experiments allowing the dynamics (TSiH and T1rρH) of CP to be determined. Comparison of SP and CP results revealed a change to a less condensed silica state when diatoms were cultured at salinities away from optimal (36 PSU). Further, an increased amount of organic material (but not its composition) was determined to be present for such samples affecting CP experiments. The location of the organic material, on the diatom surface or within the frustule, was unable to be determined.