“…Calcein ( Bis(N , N‐bis (carboxymethyl)aminomethyl)‐fluorescein ) is used to label and distinguish newly grown chambers (Bernhard et al, ), allowing the determination of growth and reproduction under controlled laboratory conditions (e.g., Diz et al, ; Hintz et al, ). Calcein was also used to check the incorporation of trace elements to the new chambers (e.g., de Nooijer et al, ; Evans et al, ; Kramar et al, ; Munsel et al, ; Nardelli et al, ; Van Dijk, de Nooijer, Wolthers, et al, ; van Dijk, de Nooijer, & Reichart, ), to assess the role of fluid‐phase endocytosis in calcification (Bentov et al, ) and in sediment samples to develop a method that can identify the location and timing of calcification (Bernhard et al, ). Possible impacts of calcein were evaluated by Bernhard et al (), Dissard et al (), and Kurtarkar et al (), who found that the marker does not affect the survival rate of individuals, incorporation of elements, nor their growth rates.…”