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The Role of a Green Alga in the Precipitation of Calcite and the Coprecipitation of Phosphate in Freshwater
Author(s) -
Hartley A. M.,
House W. A.,
Callow M. E.,
Leadbeater B. S. C.
Publication year - 1995
Publication title -
internationale revue der gesamten hydrobiologie und hydrographie
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.524
H-Index - 52
eISSN - 1522-2632
pISSN - 0020-9309
DOI - 10.1002/iroh.19950800302
Subject(s) - calcite , precipitation , coprecipitation , ionic strength , phosphate , calcium carbonate , bicarbonate , carbonate , abiotic component , darkness , environmental chemistry , chemistry , botany , mineralogy , biology , inorganic chemistry , aqueous solution , ecology , biochemistry , meteorology , physics , organic chemistry
The precipitation of calcite from a calcium bicarbonate solution, similar in ionic strength to natural hardwaters, was observed in a series of experiments utilizing an automated culture apparatus. Seeded growth experiments, using calcite seed crystals, were performed at a range of phosphate concentrations to observe inhibitory effects. These experiments demonstrated a linear relationship of increasing inhibition with increasing initial phosphate concentration. A further series of experiments was performed in which an actively photosynthesizing culture of a unicellular green alga ( Chlorococcum sp.) was added to the culture vessel in order to initiate precipitation. Experiments to observe spontaneous precipitation, occurring in the absence of both seed and alga additions, were carried out to compare with precipitation rates in the algal experiments. A control experiment was also performed to investigate whether precipitation occurrred in algal cultures maintained in darkness. The carbonate site mechanistic model, developed for calcite precipitation in abiotic conditions, was used to analyse the results of the algal experiments and found to be applicable.