Thermal Tolerance of Bull Kelp

Thermal Tolerance of Bull Kelp (Nereocystis leutkeana): Is One Population More Sensitive Than Another?

Presenter: Shelby Hotz

Presenter Status: Graduate student

Academic Year: 20-21

Semester: Spring

Faculty Mentor: Mackenzie Zippay

Department: Biology

Funding Source/Sponsor: Other

Other Funding Source/Program: National Science Foundation, Anthropocene Institute

Screenshot URL: https://drive.google.com/uc?id=19oCQy1WLCId1z3cBKRYcoxMyL5Gk0X6w

Abstract:
Between 2013 and 2016, Sonoma and Mendocino County’s coastal environment experienced a series of dramatic environmental changes: sea star wasting disease, a series of marine heatwaves creating a warm water “blob”, and a boom in purple sea urchin populations. As a direct result, these counties experienced a 90% loss in its bull kelp (Nereocystis leutkeana) coverage. The main reason for this loss is the increase in sea urchin herbivory, but there was also the concern of the effect of ocean warming caused by “blob”. Bull kelp successfully grows in water ranging from 0 to 16 ℃, and the “blob” has increased water temperatures to at least 17 ℃. To our knowledge no study has investigated the cellular effects of temperature on bull kelp. We are interested in examining heat shock response, by specifically measuring the change in gene expression and protein abundance of the heat shock protein 70 (Hsp70) in response to temperature. We will compare the heat shock responses from wild collected kelp sporophytes and lab raised gametophytes from northern and southern sites. It is possible both hsp70 gene expression and Hsp70 protein abundance will increase at cooler temperatures for northern populations, while southern populations will exhibit these changes at higher temperatures. This study is significant because it will give us a better understanding of the effects of temperature on bull kelp. The better we understand these effects, the more successful we may be in constructing management plans for bull kelp conservation in the face of continuing climate change.