Evolutionary Impacts of Urban Stressors
1. Are there genetic differences between urban and non-urban populations?
To compare connectivity and adaptation in urban and non-urban environments as a whole, I will be collecting spines and sequencing the genomes of 200 S. purpuratus from Los Angeles and San Diego (photos of collections below). Previous studies have classified pollutant concentrations along the Southern California Bight region, providing a basis for categorizing regions as “urban” or “non-urban” (Maruya et al., 2014). My hypothesis is that lower connectivity will exist among urban than among non-urban populations of urchins, similar to a previous study in a different species (Puritz and Toonen, 2011). Overall, this aim will provide a broad-scale view of the effects of urban stressors on population connectivity and adaptation in a widespread marine intertidal species.
2. Is there between population variation in developmental response due to historical exposure to Endocrine Disrupting Chemicals (EDCs) ?
Here I will be focusing on a single class of stressors, as opposed to the broad urban environment in chapter 1. EDCs such as alkylphenols and Bisphenol A (BPA) appear in many household products and are often found in high concentrations in urban waterways(Maruya et al., 2014). Larval exposure to these toxins have been found to result in developmental abnormalities in S. purpuratus, potentially affecting population dynamics. However, we do not know how tolerance or susceptibility to EDCs might vary among populations with different levels of exposure. I will be implementing a split-brood design to assess the developmental variation in urchins from both urban and non-urban environments.