text: Vital effects are biological impacts on geochemical records. Many marine organisms, ranging from zooplankton (e.g. foraminifera) to phytoplankton (e.g diatoms) to reef builders (e.g. coral), create shells or skeletons from chemical compounds dissolved in seawater. This process, which is also called biomineralization, therefore records the chemical signature of seawater during the time of shell formation. However, different species have different metabolism and physiology, causing them to create their shells in different ways. These biological distinctions cause species to record slightly different chemical signatures in their shells; these differences are known as vital effects.