Date of Award


Degree Name

MS in Biological Sciences


Biological Sciences


College of Science and Mathematics


Nikki L. Adams

Advisor Department

Biological Sciences

Advisor College

College of Science and Mathematics


Planktonic larvae of marine organisms are increasingly being exposed and required to respond to a changing physical environment. Adult sea urchins occupy both intertidal and subtidal waters and broadcast spawn gametes into the water column to contend with variable physical conditions. To answer how populations of invertebrates residing at different depths adequately prepare their offspring to cope with different levels of ultraviolet radiation (UVR), we collected adult purple sea urchins, Strongylocentrotus purpuratus, from four sites (two intertidal and two subtidal (~15 m deep)) on the central coast of CA to compare UV tolerance in offspring. Our measurements of UVA (321–400 nm) and UVB (280–320 nm) irradiance at all collection sites showed UVA and UVB were low or absent in subtidal sites compared to intertidal sites. Our study found that offspring from intertidal populations experience a less severe developmental delay when exposed to environmentally relevant levels of UVR (using artificial lighting) than offspring from subtidal populations. The mean percent cleavage delay for UV-treated embryos relative to the controls was 16% (± 2.3 SE) for intertidal sites and 21.1% (± 2.7 SE) for subtidal sites. This suggests that environmental UV cues or additional environmental cues experienced by intertidal mothers may prepare offspring to resist effects of UV exposure during early development. To further understand differences in biochemistry of the eggs released from mothers of different populations (i.e. differences in maternal investment), we assessed differences in protein abundance among batches of eggs from intertidal and subtidal populations. We identify a range of candidate proteins involved in various cellular processes such as cell cycle regulation, signaling and transport, oxidative stress and metabolism that may help developing embryos cope with UVR stress. These candidate proteins may also help us understand adaptations important for survival of developing marine organisms in changing ocean conditions.

Available for download on Monday, September 04, 2023