title: Sunlight-enhanced calcareous deposition on cathodic stainless steel in natural seawater.
abstract: In replicate series of experiments in natural seawater, one in full darkness and the other in a 1:1 diurnal cycle with as little as ~5% of natural solar illumination, sunlight promoted calcareous deposition on cathodic stainless steel surfaces. As exemplified by scanning electron microscopy, the deposit that formed under the natural diurnal cycle, in the presence of photosynthetic biofilms, was composed of finer calcareous crystals that provided more compact and more uniform surface coverage than the one formed in the dark. The light-enhanced deposit also possessed better scale properties, as suggested by X-ray analysis and electrochemical measurements. Sunlight enhancement of calcareous deposition looked all the more conspicuous when day and night regimes were examined independently. These results not only bear important implications for cathodic protection in marine waters, but also provide an intriguing analogy to coral reef calcification.
authors: Corrosion Research Centre, CSIR - Central Electrochemical Research Institute, Mandapam Camp 623519, Tamil Nadu, India. meashwar1960@yahoo.in
authors: M
authors: M
authors: Eashwar
authors: P
authors: P
authors: Sathish Kumar
authors: R
authors: R
authors: Ravishankar
authors: G
authors: G
authors: Subramanian
mesh_terms: D018441:Biofilms; D002119:Calcium Carbonate / Q000737:chemistry*; D003460:Crystallization; D018360:Crystallography, X-Ray; D003624:Darkness; D017377:Diatoms / Q000737:chemistry / Q000502:physiology; D055664:Electrochemical Techniques; D004566:Electrodes; D007194:India; D008274:Magnesium / Q000737:chemistry; D008386:Marine Biology / Q000379:methods; D008855:Microscopy, Electron, Scanning; D010788:Photosynthesis; D012623:Seawater; D013193:Stainless Steel / Q000737:chemistry / Q000528:radiation effects*; D013472:Sunlight; D013499:Surface Properties; D013696:Temperature
chemical_list: D013193:Stainless Steel; D002119:Calcium Carbonate; D008274:Magnesium