The effects of competition and purple urchin grazing on the recovery of giant kelp forests
Calvin Munson – Raimondi-Carr Lab
Positions: 1 – 2 interns
Tentative dates: 6/23/25 – 8/29/25 (though the project will start in limited capacity in the Spring and go into the Fall)
Project Location: Labs on Coastal Campus in CBB and OHB, field trips in Monterey (Hopkins Marine Station)
Project Background: Forests of giant kelp have declined dramatically along central California in response to the 2014-2016 marine heatwave. In many areas, forests have transitioned to “sea urchin barrens” devoid of algae and covered with purple sea urchins. There is great interest in understanding the process of forest recovery, in part to inform possible restoration efforts. We are using kelp cultivation techniques and mesocosms (cattle troughs) at CBB and Long Marine Lab to experimentally evaluate the role of intra-specific competition and sea urchin grazing on the survival of young kelp sporophytes. We are also conducting parallel subtidal experiments to replicate these methods in the field, which involves SCUBA diving to outplant kelp into urchin barrens and track its survival. Results of these studies will allow researchers and managers to better understand the levels of kelp recruitment and sea urchin densities for kelp recovery.
Intern duties: The intern(s) will engage and assist in all elements of these experiments, including the design, implementation (kelp culturing in CBB, setup of the experiments, observation and data collection) and analysis. Kelp culturing will consist of the identification and quantification of early kelp life stages (spores, gametophytes, sporophytes) under microscopes and the maintenance of proper conditions for growth. The position will primarily be lab/mesocosm work, but if the intern(s) are scientific diving certified, they will have the opportunity to participate in implementing the field experiment on SCUBA. This will involve multiple days of boat-based diving a week to set up experimental plots, outplant kelp, remove urchins to target levels, and track the survival of kelp. Non-diving students may also occasionally join to be surface support (helping from the boat) during field trips.
Additionally, the mentor (Calvin) will teach the students coding in the R statistical software in order for them to conduct their own data analyses and visualizations for their final CAMINO products (no coding experience is necessary). The objective is to mentor the student through all aspects of an experimental research project. Fortunately, the lab and mesocosm components are short (4 weeks), which makes multiple rounds of experimentation feasible and not subject to weather conditions.
Intern qualifications: Lab experience (biology, chemistry, etc) is preferred. AAUS scientific diving certification is required for participation in SCUBA-based field work (but note that this is not required to participate in the lab and mesocosm work).
Do you recommend the intern(s) volunteer in your lab during Spring quarter?
Volunteering in the lab over the Spring would be useful – but not necessary – for both the lab-based or field-based work.