Calculating boring rate of endolithic cyanobacteria Hyella immanis under laboratory conditions

Extensive microbial studies of the Arabian Gulf marine environment have led to the discovery of several new species of endolithic cyanobacteria. Those species were taxonomically classified under cyanophyta and belonging to the genes Hyella, Solentia and cyanosacus. In this study Hyella immanis was isolated and cultured under laboratory conditions and used as a model to calculate boring rates for genus Hyella. Boring rates were measured under light intensity of 20-25 μE m^-2 s^-1 of 16:8 h LD cycle, 1 h d^-1 agitation, and no agitation. Light, Scanning Electron Microscopy (SEM) and embedding techniques were used to provide information on boring rates, boring patterns, and cells morphology. Mean boring rates of seven colonies were found to lie between 166 and 510 μm³ d^-1 at various growth stages, with a boring rate of 10 μm d^-1 in calcite. Calculated boring rates tend to be accelerated at early stage of colony development and enhanced with agitation. Rates of calcite removal for control and under agitated conditions in early stage (20-50 day) were 150 μm³ d^-1 and 357 μm³ d^-1 respectively. However, in late stage (50-70 days) control and agitated conditions removal was 185 μm³ d^-1 and 173 μm³ d^-1 respectively.