Table of Contents

• Coverage
• Dataset Description
  • Methods & Sampling
  • Data Processing Description
  • BCO-DMO Processing Description
  • Problem Description
• Related Publications
• Parameters
• Instruments
• Project Information
• Funding

Data were collected during day-trips aboard the California Department of Fish and Wildlife or UC Davis boats, generally 2-3 days to sample the twelve RMs.

We used specially designed recruitment modules (RMs) bolted into the rocky subtidal reef to sample recruitment of larger juvenile abalone and sea urchins (3 to 20 millimeters (mm)). Standardized RMs were deployed at Van Damme State Park (VDSP) (latitude 39°16'08"N, longitude 123°47'58"W), northern California in August 2000. RMs were made of stainless steel cages filled with concrete cinder blocks cut lengthwise resembling the letter M (rectangles measuring 813 mm x 610 mm x 305 mm high) and stacked three levels tall. Each RM had a surface area of approximately 4.8 square meters (m²), of which 2.6 m² was a sheltered area created by the sides, top, and bottom of each M shape.

Twelve RMs were deployed between 10 and 12 meters (m) depth in three groups of four. The modules were placed 3-6 m apart within the cluster of four. The northern cluster was approximately 140 m from the central cluster. The southern cluster was 710 m from the central cluster.

RMs were deployed and left to season for one year before the first surveys began in August 2001. Each year thereafter in August the RM would be surveyed and if any half cinder blocks were missing they would be replaced. In the year of 2014, half the RM cages were replaced with new cages and in the year 2015, the remaining 6 modules were replaced. In each case, the existing bricks were reused in the same module. In some years fewer than 12 RM were surveyed, due to older RM cages being damaged by winter storms. Each year the numbers of invertebrates are reported per module. During the years 2020 and 2021, no RM surveys were conducted due to field work constraints imposed to reduce the spread of COVID.

The surveys involved one dive team for each RM, opening the lid and carefully removing each block, then counting and measuring all the invertebrates inside the RM. Organisms outside the cage were not sampled. Organisms too numerous to count were gently swept into fine mesh bags (2 mm) to be counted and measured at the surface. Organisms cemented to the brick were measured and quantified underwater. Each block was set to the side while the next block was removed, and the animals quantified. When a survey was completed, divers reassembled the RM and replaced the lid, securing it with wide cable ties. Each RM took two divers approximately 40-50 minutes to survey depending on the contents.

Data were entered from the field sheets into an Excel spreadsheet, one year per worksheet. The data were proofed against the field sheets in 2024 and transferred in tabular form to a single Excel sheet. The sheet was given a version number and also saved in a file as comma-separated values (CSV).

Some years have less than 12 RMs due to storm damage. RMs were repaired or replaced when damaged. The process of replacing all of the RMs began in 2014. An "A" or "B" preceding the last number was used when an RM was replaced, "B," and those retained, "A", until all were replaced.

- Imported original file "NSF_OCE_2023664_KelpForestSurveys_Species_CODES_v2_20240119.csv" (species code list) into the BCO-DMO system.
- Imported original file "NSF_OCE_2023664_KelpForestSurveys_RECRUITMENT_MODULES_v2_20240817.csv" (RM data) into the BCO-DMO system.
- Added the following columns from the species code list to the RM data: CommonName, ScientificName.
- Saved the final file as "929812_v1_abalone_and_urchin_recruitment_modules.csv".

NSF Award Abstract:
Rapid and extreme warming events such as El Niño and marine heatwaves have had ecological and economic impacts on nearshore marine ecosystems. These impacts include reductions in biomass and collapses in commercial fisheries. For many species, population booms and busts are controlled by shifts in reproduction and juvenile dispersal related to warmer temperatures and ocean circulation. However, how population fluctuations are shaped by interacting processes that control adult reproduction and larval survival remains unclear. Marine heatwaves often accompany major disruptions in ocean circulation, which can affect survival and the distribution of species that produce free-floating, planktonic larvae. As a result, species can be impacted directly by temperature effects on organismal reproduction and survival, and indirectly by shifts in ocean circulation that affect larval success. This project is examining how the joint effects of temperature and ocean circulation are controlling populations of purple sea urchins (Strongylocentrotus purpuratus). To address project objectives, the team is developing oceanographic models to predict dispersal of planktonic larvae in combination with controlled experiments on adult reproductive success. This project is advancing the understanding of how ecologically important species respond to ocean temperature and circulation, which are forecast to shift under future climate change scenarios. Broader impacts of the project include training of students and post-docs in STEM and educational outreach. Curriculum development and implementation is occurring in collaboration with existing K-12 outreach programs that focus on underserved communities and under-represented groups. The goal is to empower the next generation of scientists to use integrative approaches to predict ecological consequences of climate change.

Purple sea urchins are an ideal species for studying the coupled impacts of warming and ocean circulation on recruitment and survival given a wealth of ecological and organismal data. The species has a mapped genome, can be transported large distances as larvae by ocean currents, and larval abundances in California exhibit orders of magnitude variation with heatwaves and El Niño fluctuations. To quantify the processes that shape spatial and temporal variability in larval supply, researchers are applying a novel combination of biophysical modeling, experiments and statistical modeling of long-term, high-resolution data on larval settlement across the Southern California Bight (SCB). Research module 1 is quantifying spatial and temporal patterns of larval transport using a 3D-biophysical model of the SCB. The model is testing how interactions among historical changes in ocean circulation and temperature, larval life history, and larval behavioral traits affect variation in larval supply in space and time. Research module 2 is focused on how temperature could affect spatial and temporal variation in egg production. Experiments are characterizing reproductive thermal performance curves and quantifying how these vary among populations and organismal history. A novel assay is assessing epigenetic regulation of gene expression associated with performance curves. Finally, Module 3 will integrate mechanistic models from Modules 1 and 2 to statistically assess their ability to explain spatial and temporal trends in a nearly three-decade dataset of larval settlement from six sites in the SCB. This is one of the first studies that integrates models of larval transport, reproductive performance and settlement data to empirically test how physical and biological processes affect local recruitment patterns in complex marine meta-populations.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.