Herbivory and Recruitment Limitation in Kelp Forest

A group of six hikers walking through a grassy meadow towards a forest of tall evergreen trees under a clear blue sky.

Herbivory and Recruitment Limitation in Kelp Forest

Mentor & Lab: Andrea Paz-Lacavex – Raimondi – Carr Lab

Positions: 2 interns

Tentative dates: June – September (flexible)

Project Location: Long Marine Lab and Hopkins Marine Station, Monterey

Project Background: Giant kelp forests (Macrocystis pyrifera) along the Baja California and California coasts have experienced significant declines in recent years, with many areas transitioning into persistent urchin barrens. Through field and laboratory experiments, we have identified recruitment limitation of benthic assemblages caused by herbivory from the widely studied purple sea urchins (Strongylocentrotus purpuratus) but also from the understudied giant turban snails, including red turban snails (Pomalaux gibberosus). This summer, we will conduct two complementary experiments to test whether snail grazing plays a significant role in the maintenance and creation of barrens on the central coast when compared to purple sea urchins. One experiment will involve a SCUBA-based caging study at Hopkins Marine Station in Monterey Bay to measure the impact of P. gibberosus on kelp recruitment. Additionally, in the Long Marine wet lab, we will culture kelp to assess the grazing rates of P. gibberosus across different size classes and compare them to those of S. purpuratus. This study will provide novel insights into the ecological processes that shape the resilience of kelp forests and influence the broader benthic community structure.

Intern duties:

Intern(s) will play an integral role in this research by assisting with both field and laboratory experiments. SCUBA experience preferred but not necessary. Specific responsibilities include:

  • Wet lab component
    Setting up and maintaining grazer-exclusion experiments in the wet lab
    Kelp culturing from spores to sporophytes
  • SCUBA component
    Conducting measurements of kelp sporophyte growth and survival under different grazing pressures
    Identifying and quantifying benthic organisms to evaluate community structure and richness
  • Both components
    Capturing and processing subtidal monitoring data

Maintaining equipment, tanks and organizing experimental logistics.

Intern qualifications:

Intern(s) will:

  • Be comfortable working in wet lab and coastal field conditions, including carrying moderate loads (~25 lbs) and and long hours outdoors and sometimes in the wet lab during the weekend.
  • Have strong attention to detail for data collection and data QA&QC.
  • Be willing to handle biological specimens, including live grazers and kelp blades.
  • Optional experience but not required: active AAUS scientific diver, data analysis (e.g., R or Excel), work with marine organisms or in a wet lab, microscopy.

Do you recommend the intern(s) volunteer in your lab during Spring quarter?
The field season will begin in April, 2025. Students are welcome to volunteer in a regular schedule if their availability allows.