Most of the species studied are broadcast spawners because fertilization and complete pelagic larval life occur in the water column. Whether BAY 73-4506 alternative reproductive modes are affected in a changing ocean is still poorly documented. Niltubacin Brooding and/or egg laying in egg masses or capsules are typically assumed to confer protection to developing embryos. For example, it has been shown that encapsulated embryos of some gastropod species survive better in conditions of salinity stress than embryos removed from their capsule. A few studies have explored the effects of decreased pH on embryos brooded and/or laid in benthic gelatinous egg masses or in egg capsules in bivalve, gastropod or cephalopod mollusks. Depending on the study, reduced pH has different effects that are related to the range of species habitats and the strategy to protect embryos studied as well as the source of pH change. Encapsulation has been suggested to protect embryos against ocean acidification, whereby the buffer capacity of intracapsular fluids may reduce the potential effect of extracapsular elevated pCO2 seawater. To study this issue in a non-broadcast-spawner species, we chose the slipper limpet Crepidula fornicata, Linne´ 1758 as our biological model. Native to the northeast American coast, this species was introduced in Europe at the end of the 19th century, primarily via oyster farming, and has now become invasive in bays and estuaries where it reaches very high densities of up to several thousands of individuals per m2. It has a bentho-pelagic life cycle, with a number of original features. Benthic adults form stacks with males at the top and females at the bottom. After internal fertilization, females brood their embryos in egg capsules for 3 to 4 weeks. Capsules are protected between the neck and the propodium of the female parent and attached to the substratum to which the female is fixed. Each female spawns between 28 and 64 capsules, each containing 300 to 500 embryos. At the end of capsular development, veliger larvae are released at a size of about 400 mm in length into the water column where they spend between 2 and 7 weeks. Upon reaching competence, larvae are able to metamorphose and settle on hard substrata. The objective of this work was to investigate the effects of nearfuture levels of pCO2 on the development of C. fornicata encapsulated embryos by studying the shell morphology and mineralization level of released larvae. To ensure that the complete development, from the egg to the released larva, occurred under high pCO2, parents were conditioned to the different pCO2 levels before mating occurred. In our study, the effects of elevated pCO2 were integrated from embryo formation and throughout embryonic stages up until the release of veliger larvae. The integration of pCO2 effects across all developmental stages, from fertilization to settlement and beyond, is particularly instructive because early life stages may respond to environmental stressors in a different way than adults. Acute exposures of early life stages have shown various effects in growth or feeding performances, but these may not represent field conditions. Results obtained from acclimation to high pCO2 across different life stages often differ from those arising from acute exposure of a given stage.