Stanley Ko

2014 Research Experience for Undergrads

StanleyFor my 2014 JISAO internship, I had the pleasure of working with Dr. Timothy Essington and his graduate student, Emma Hodgson. We developed life history models for Euphausia pacifica, the predominant krill species in much of the Northern Pacific Ocean. This species feeds primarily on phytoplankton and are fed on by baleen whales and commercially harvested fish like salmon, sardines and albacore. Thus, they serve as a significant link between primary production and upper tropic levels in marine ecosystems. Ocean acidification, the decrease in pH and change in carbonate chemistry as a result of the oceanic uptake of anthropogenic carbon dioxide, may threaten this link. Euphausiids are calcifying organisms and are susceptible to ocean acidification.

Given the influential role of E. pacifica, it is important to understand how the species will respond to changing environmental conditions. Because its exposure and vulnerability varies by life history stage, the relative importance of stage-specific demographic parameters is required to translate these effects to the population level. Discrete stage-based life history models were used to identify the stages critical for population persistence. Parameters were taken from experiments and observations of the species off the coast of Oregon and California. A density independent model was created using a Lefkovitch matrix which yielded the population growth rate and elasticity values. The density dependent model was an analytical model which yielded the equilibrium population of the adults. Ocean acidification was simulated in both models by decreasing survival rates for various stages. The growth rate was most sensitive to parameters affecting the juvenile and adult stages.

This internship was much more than my project. As a prospective graduate student, the networking opportunities and tours arranged by JISAO, lab meetings and time spent with graduate students were invaluable and gave me tremendous insight on my future. It has been a great experience and I’m already beginning to miss it.



Stanley's research poster

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