Quantification of carbonate crystals using FTIR technique in some calcareous algae occurring along the southeast coasts of India

Abstract

<span style="font-size:9.0pt;font-family: " times="" new="" roman","serif";mso-fareast-font-family:"times="" roman";mso-ansi-language:="" en-gb;mso-fareast-language:en-us;mso-bidi-language:hi"="" lang="EN-GB">In this study, morphological volume, biomass, total carbonate biominerals and crystal biominerals (calcite, aragonite and dolomite) were recorded for eight species of calcareous algae (CA) which occur abundantly along the southeast coast of India. Morphological volume was inversely proportional to biomass in all the CA studied. Total carbonate biomineral content recorded by decalcification was higher than the total crystal biomineral content recorded by FTIR spectroscopy and the differences were less depends on algae. Using FTIR spectroscopy, calcite, aragonite and dolomite were detected in all the samples of calcareous red and green algae, whereas only calcite was detected in the brown alga. High biomass was recorded in CA with low morphological volume, and they can be arranged in the following decreasing order: <i>Corallina elongata, Amphiroa fragilissima</i>,<i style="mso-bidi-font-style: normal"> Jania rubens, Udotea peltata, Halimeda opuntia, H. macroloba, Neomeris annulata<span style="mso-bidi-font-weight:bold"></i>, and <i>Padina boergesenii</i>. Among the crystal biominerals, calcite was found in major quantity; aragonite, moderate quantity; and dolomite, minor quantity. FTIR <span style="mso-bidi-font-weight:bold">spectroscopy adopted in this study<span style="mso-bidi-font-weight:bold"> is found to be a promising alternative technique to quantify the composition of <i>in situ</i> crystal <span style="mso-bidi-font-weight:bold">biominerals in CA. Accumulation of crystal biominerals in CA is not only species specific but also depends on the choice of coasts.</span></span></span></span></span>