Abstract: Many modern continental shelves are areas of calcareous faunal and floral growth and subsequent carbonate accumulation. These de- positional environments can be subdivided into three major zones: (1) tropica I/warm-water; (2) temperate/cool-water and (3) polar/cold-water. Our research focused on the temperate environment. We analysed 51 samples of corals, coralline algae and bryozoans and 9 calcitic cements from bottom sediment samples from the Lacepede Shelf, South Australia for their mineralogy, oxygen and carbon isotopes, and distribution of major, minor and trace elements. Azooxanthellate corals are depleted in 8 18 0 and 8 I3 C in comparison to equilibrium values but less so than their tropical counterparts. Coralline algae are enriched in 8 18 0 and 8 I3 C compared to tropical samples. Both azooxanthellate corals and coralline algae display a positive correlation between their isotopes. The bottom temperature versus S ls O curve for the aragonitic bryozoan Adeona sp. parallels the equilibrium aragonite curve. These B 1S 0 values are in equilibrium with the ambient water but differ from those for Adeona sp. from the Indian (tropical) Ocean. Its 8 13 C content is almost in equilibrium and higher than its tropical counterpart, despite lower 8 13 C values for dissolved inorganic carbon (DIC) in the study area. This study shows that carbon isotope disequilibrium of carbonate-rich biota is greater than that of oxygen isotopes. Furthermore, the isotopic ratios for similar organisms are different from one environment to another. Even more importantly, diverse organisms living in the same environment may have dissimilar isotope values. This can be attributed to either metabolic processes or kinetic effects. For the former, photosynthesis is the major cause of 8 I3 C enrichment in photosynthetic organisms, and respiration induces some depletion. Extrinsic factors (e.g., depth, salinity, temperature, turbidity, substrate, and oxygen levels, etc.) variably mediate differences. Organisms with aragonitic mineralogy, such as corals and some bryozoans, have higher Sr and lower Mg, Fe and Mn concentrations than calcitic ones (e.g., coraUine algae). These differences may be functions of various combinations of the following processes: (a) mineralogical discrimination against some trace elements, (b) skeletal formation process, (c) environmental variables and (d) physiology of the organism. Differences between temperate and tropical biotic geochemistry may be useful for differentiating between temperate and tropical environments in the rock record, providing diagenesis has not altered the primary signatures.