Developmental and Transcriptomic Responses in Sea Urchin Larvae to an Urban-Associated Pollutant

Urban environments provide a unique opportunity to investigate the impacts of novel stressors on organismal performance. Marine intertidal zones exist at the transition from sea to land, where they are exposed to a unique suite of stressors, including those associated with wastewater outflow, sewage effluent, and coastline development. Although studies have shown that compounds found in wastewater, including endocrine disrupting chemicals (EDCs), can affect the survival and development of marine organisms, the mechanisms for those effects are relatively unknown. Our study investigates the developmental and transcriptomic responses to a common EDC, nonylphenol, using the Pacific purple sea urchin (Strongylocentrotus purpuratus) as a model system. Beginning exposure prior to fertilization, we found that nonylphenol impacts only materialize 24 h postfertilization when the embryonic transcriptome begins to be expressed, and these impacts vary significantly by mate pair. In addition, survival was lowest at the lowest concentration of nonylphenol. Transcriptomic patterns also varied by chemical concentration and developmental stage, with ribosomal genes differentially expressed among different treatments at both early and later larval stages. We also found a strong parental effect: survival, morphology, developmental abnormalities, and gene expression vary among mate pairs despite all of the adult urchins coming from the same population. This potentially suggests standing within-population variation, which may impact evolutionary responses to anthropogenic stress. Overall, our study finds that nonylphenol affects survival, morphology, and gene expression at early life history stages, and that more work needs to be done to understand intraspecific variation in those effects.