title: The Micro-mechanism Involved and Wollastonite Signature in the Calcareous Precipitates of Marine Isolates.
abstract: Micro-mechanical studies connecting the influence of extrinsic factors over intrinsic factors on 30 calcareous isolates obtained from marine sediment biofilms of the Bay of Bengal (Indian Ocean) revealed that the fate of calcareous crystal precipitation is highly dependent on factors like extracellular polysaccharides (EPS), organic carbon and nutrition. Further studies exemplified that EPS and the organic carbon secreted by the isolates controlled the dissemination of the calcareous crystals precipitated. From the study, it is evident that an EPS concentration of 7-15 mg l(-1) was found to enhance the dissemination of the calcareous crystals. Atomic force micrographs explain the nucleation behaviour and morphology of the calcareous crystals precipitated. X-ray diffraction (XRD) and energy-dispersive X-ray spectroscopy (EDAX) showed that the crystals were mainly composed of calcite and partially wollastonite.
authors.affiliation: CSIR-Structural Engineering Research Centre, Taramani, Chennai, 600 113, India. sarayu_1528@yahoo.co.in.
authors.forename: K
authors.initials: K
authors.lastname: Sarayu
authors.affiliation: CSIR-Structural Engineering Research Centre, Taramani, Chennai, 600 113, India.
authors.forename: Nagesh R
authors.initials: NR
authors.lastname: Iyer
authors.affiliation: CSIR-Structural Engineering Research Centre, Taramani, Chennai, 600 113, India.
authors.forename: M
authors.initials: M
authors.lastname: Annaselvi
authors.affiliation: CSIR-Structural Engineering Research Centre, Taramani, Chennai, 600 113, India.
authors.forename: A
authors.initials: A
authors.lastname: Ramachandra Murthy
mesh_terms: D001419:Bacteria / Q000145:classification / Q000378:metabolism*; D002119:Calcium Carbonate / Q000737:chemistry; D017610:Calcium Compounds / Q000737:chemistry*; D018360:Crystallography, X-Ray; D019015:Geologic Sediments; D008386:Marine Biology; D018625:Microscopy, Atomic Force; D017640:Silicates / Q000737:chemistry*; D013052:Spectrometry, X-Ray Emission
chemical_list: D017610:Calcium Compounds; D017640:Silicates; D002119:Calcium Carbonate; C031293:calcium silicate
keywords: Calcareous materials; Calcite; EPS; Marine isolates; Wollastonite