text: BSi preservation is measured by:
  * Sedimentation rates, mainly sediment traps (Honjo);
  * Benthic remineralization rates ("recycling"), benthic flux chamber (Berelson);
  * BSi concentration in sediments, chemical leaching in alkaline solution, site specific, need to differentiate lithogenic vs. biogenic Si, X-ray diffraction.
  BSi preservation is controlled by:
  * Sedimentation rate;
  * Porewater dissolved silica concentration: saturation at 1.100 μmol/L;
  * Surface coatings: dissolved Al modifies solubility of deposited biogenic silica particles, dissolved silica can also precipitate with Al as clay or Al-Si coatings.