In vitro effects of a plastic additive (DEHP) on contraction dynamics of Hymeniacidon heliophila (Demospongiae: Halichondrida)

Microplastic impacts in marine ecosystems are a major topic in ocean pollution research. Besides the problems caused by the particles, additives used in its manufacture, such as phthalates, can leach from the particles. Once in the environment or inside the organisms, these compounds can bioaccumulate and cause endocrine disruption in several marine organisms. Although marine sponges are efficient filter feeders, limited research has explored the potential physiological impacts of these additives on these organisms. To verify possible effects of the additives in sponges, individuals of Hymeniacidon heliophila were exposed to different concentrations of di-(2-ethylhexyl)-phthalate (DEHP). Expansion-contraction cycles were monitored by time-lapse photography and parameters of in vitro cell cultures (primmorphs), such as number and size, were analyzed. Exposition to DEHP caused alterations in the contraction-expansion cycles and dose-dependent effects on the volume of the canals of the aquiferous system. Cell aggregation parameters in the primmorph cultures were not altered. However, the effects on the organisms were not permanent, with the sponges being able to recover their natural expansion-contraction cycle. Possible mechanisms involved in the effect of DEHP in the sponges and detoxification pathways are discussed.