Abstract:
Certain groups of marine organisms such as corals, foraminifera, and bivalves produce skeletons or shells made of calcium carbonate (CaCO3) minerals, chiefly in the form of calcite or aragonite. These biominerals do not occur as compositionally-pure CaCO3, as numerous ionic constituents of seawater are regularly incorporated during their formation as impurities. First, the degrees and patterns of incorporation of ionic impurities and their isotopic signatures in CaCO3 depend on physicochemical conditions of seawater (e.g., temperature) at the time of mineral formation. This makes skeletal or shell CaCO3 important archives of past changes in environmental conditions over various timescales. Second, incorporation of ionic impurities can affect CaCO3 crystalline structure, in turn modulating mineral solubility and preservation in marine sediments, with potentially important biogeochemical and climatic implications.

In this presentation, I briefly describe how I integrate the use of inorganic experiments in the laboratory and the actual marine CaCO3 biominerals to study the two aspects of ionic impurities in CaCO3. I will also make the case why these types of research projects are readily transferrable and well-suited for student training.