Table of Contents

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

All surveys were done using Scuba along 30-meter x 2-meter (m) transects randomly placed in the subtidal zone in rocky habitats dominated by bull kelp, Nereocystis luetkeana, forests. These randomly placed band transect surveys were stratified by depth (A=0-15, B=16-30, C=31-45, D=46-60 ft) as we know sea urchin and abalone populations differ by depth.

Each diver (2 divers) surveyed a 1-m wide swath along each the transect, collecting the following data: the number of live, dying (in some years during the mass mortality events), and sea urchins (red-Mesocentrotus franciscanus and purple-Strongylocentrotus purpuratus), red abalone (Haliotis rufescens), pinto abalone (H. kamtschatkana), flat abalone (H. walallensis), as well as empty abalone shells (again in some years).

The data specific to this dataset are the percentages of four different substrate types: reef, boulder, cobble, and sand. Data on the substrate types differed depending on the year and the focus of the studies in response to ecosystem conditions. Note that some transects were subsampled: "L" is left side, "R" is right side, "LR" is the entire 30m x 2m transect, both sides. Not all transects were subsampled due to time constraints; not all survey transects were sampled.

In some rare cases, substrate can range from 95-105 for a subsample, and from 190-210 for both sides of the full transect, so they should be rounded off to 100 or 200%.

Data were entered onto waterproof data sheets during each survey. The field sheet data were then entered into a Microsoft Access database, where sorted and exported to Excel files. Once data were proofed and errors in calculations of percentages reduced to within 5% of 100% for each side of a transect, they were saved as an Excel file and a text file as comma-separated values (CSV).

Note that substrate percentage should add up to 100% on one side of the transect or 200% for both sides of the transect. In some rare cases substrate can range from 95-105 for a subsample, and from 190-210 for both sides of the full transect, so they should be rounded off to 100 or 200%.

- Imported original files "NSF_OCE_2023664_KelpForestSurveys_SUBSTRATE_CODES_v1_240122.csv" (substrate code list) and "NSF_OCE_2023664_KelpForestSurveys_LOCATIONS_v4_20240105.csv" (site code list) into the BCO-DMO system.
- Imported original file "NSF_OCE_2023664_KelpForestSurveys_SUBSTRATE_v7_20240725.csv" (substrate coverage data) into the BCO-DMO system.
- Added the following columns from the site code list to the substrate coverage data: SiteName.
- Added the following columns from the substrate code list to the substrate coverage data: Substrate Description.
- Renamed fields to comply with BCO-DMO naming conventions.
- Converted the SurveyDate column to YYYY-MM-DD format.
- Saved the final file as "928527_v1_kelp_forest_substrate_coverage.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.