Urban environments provide a unique opportunity to investigate the impacts of novel stressors on organismal performance. Marine intertidal 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. While studies have shown that compounds found in wastewater, including endocrine disrupting chemicals (EDCs) can affect survival and development of marine organisms the mechanisms for those affects are relatively unknown. Our study investigates the developmental and transcriptomic responses to 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 hours post fertilization when the embryonic transcriptome begins to be expressed. 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 levels of exposure at both early and later larval stages. We also find 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 suggesting 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.

The interaction between selection and gene flow can determine to what degree populations are able to adapt to local environmental conditions. This presents a particular conundrum in marine systems, as many marine species have high dispersal capacity resulting in nearly panmictic populations. Increasingly, genomic studies find that even in systems with little or no population structure divergence at particular loci may indicate local adaptation in the presence of high gene flow. However we are just beginning to understand which environmental variables might be the strongest drivers of selection in marine systems and the functional outcomes of genetic variants that are candidates for selection. Here, we leverage fine-scale sampling across the California range of the Pacific Purple Urchin (Strongylocentrutus purpuratus), a species with previous evidence of both local adaptation and extremely high gene flow. We find that despite complete absence of neutral population structure, sea surface temperature and tidal height drive genetic differences among populations, suggesting that balanced polymorphisms can lead to adaptation across both large scale (latitudinal) and small scale (subtidal v. intertidal) scales. Further, we find that genes that are expressed at a single tissue or life history stage are more divergent than expected across both latitudinal and tidal height comparisons, suggesting that these genes have specific functions that might generate phenotypic variation important for local adaptation. Together these results suggest that even in panmictic populations genetic variation can be sorted across even small spatial scales, potentially resulting in local adaptation across a complex environmental mosaic.