UC Marine Council

Many marine organisms have a planktonic phase that can last for days to months, during which larvae are able to disperse away from their natal populations (Eckman 1996). Although ecologists have been interested in the effect of the transport and exchange of larvae between marine populations for decades, tracking larval trajectories has been challenging (Levin 1990). An understanding of larval transport and recruitment is crucial for effective coastal zone management, especially when considering the use of marine reserves for enhancement of fisheries and preservation of biodiversity.

One technique of larval tracking that has received increasing attention in the past decade is "elemental fingerprinting". While organisms are forming, they incorporate various trace elements (such as metals introduced to the water through pollution) into their body tissues in relationship to temperature and chemistry of ambient water. If the water composition is sufficiently different at different locations, it is possible to identify where larvae came from by analyzing the chemical composition of hard parts they formed earlier in their lives.

For my dissertation, I will develop and utilize elemental fingerprinting on mussel shells (Mytilus spp.). The purpose of my work is to determine the degree of self-seeding of juveniles entering a marine reserve, Cabrillo National Monument in San Diego. I hypothesize that the kelp forest offshore of the reserve acts as a barrier to water motion and therefore retains locally spawned larvae while partially excluding larvae from elsewhere. I will compare the elemental fingerprint of young mussels on either side of the kelp forest to test this theory. This technique is broadly applicable to any species with a planktonic larval phase during which permanent hard parts are formed. The application of this technique to explore transport and retention questions will assist managers to design and protect marine reserves in California.