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Evolutionary Impacts of Urban Stressors on a Marine Invertebrate Species

1. How do urban-associated pollutants affect larval development and gene expression patterns

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).  Exposure to these toxins have been found to result in developmental abnormalities in S. purpuratus larvae, potentially affecting population dynamics. However, we do not know how tolerance or susceptibility to EDCs might vary among populations with different levels of exposure. In my first chapter I will build a baseline of exposure effects to identify developmental and transcriptomic shifts. In my second chapter I will delve into the role of historical exposure of EDCs, implementing a split-brood design to assess the developmental variation in urchins from both urban and non-urban environments.


2. How does the urban environment as a whole affect evolution in urban marine invertebrate populations?

To identify potential signals of adaptation in urban environments, I have collected spines from urchins in urban and non-urban sites in Los Angeles (n=7) and San Diego (n=3). 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). I have also collected spines from urchins in urban and non-urban sites in Victoria B.C. (n=4), to represent a coastal urban city in a geographically distinct region that also has some research on urban pollutants in the area. Using this paired urban-nonurban site design, I will be able to disentangle genetic variation associated with geographic proximity and genetic variation due to high selection in marine urban environments and identify selection in marine urban environments.