Table of Contents

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

We recorded ocean temperature at five intertidal sites in Northern and Central California (Kruse Ranch, Bodega Marine Reserve, Hopkins Marine Station, Soberanes Point, and Vandenberg) by deploying two TidbiT dataloggers (Onset Computer Corp.) in the intertidal zone at each site in June 2022, which recorded temperature at 30 min intervals. We anchored dataloggers in small steel mesh cages bolted to the substrate.

Temperature data were filtered to only include readings recorded within 1.5 hrs of high tide. Datasets were trimmed to ensure that only water temperature readings were included and not aerial temperatures.

- Loaded dataloggers_temp from dataloggers.temp.csv with header row 1; empty strings and "nd" treated as missing values
- Applied find_replace on Datetime.logger to replace date-only values (matching pattern ^\d+/\d+/\d+$, i.e. values with no time component) with empty string, treating them as missing
- Renamed columns: Datetime.logger to Datetime_logger, H1 to hightide_1, H2 to hightide_2
- Converted Datetime_logger from format %m/%d/%y %H:%M (Pacific Time) to ISO 8601 datetime string %Y-%m-%dT%H:%M in Pacific Time, output to new column Datetime_logger_PT, preserving metadata
- Converted Date from format %m/%d/%y to ISO 8601 date format %Y-%m-%d, overwriting the Date column in place, preserving metadata
- Converted hightide_1 from format %m/%d/%y %H:%M (Pacific Time) to ISO 8601 datetime string %Y-%m-%dT%H:%M in Pacific Time, overwriting hightide_1, preserving metadata
- Converted hightide_2 from format %m/%d/%y %H:%M (Pacific Time) to ISO 8601 datetime string %Y-%m-%dT%H:%M in Pacific Time, overwriting hightide_2, preserving metadata
- Converted Datetime_logger_PT from format %Y-%m-%dT%H:%M (Pacific Time) to UTC datetime string %Y-%m-%dT%H:%MZ, output to new column Datetime_logger_UTC, preserving metadata
- Deleted original Datetime_logger column
- Reordered columns to: Datetime_logger_PT, Datetime_logger_UTC, Temp, Date, hightide_1, hightide_2, Logger, Site, Latitude, Longitude
- Renamed hightide_1 to Datetime_hightide_1_PT and hightide_2 to Datetime_hightide_2_PT
- Renamed table from dataloggers_temp to 1000482_v1_datalogger_temp
- Output final table to 1000482_v1_datalogger_temp.csv

NSF abstract:
Anthropogenic climate change is shifting the distributions of species across the globe. Such contemporary shifts in species’ ranges may have cascading effects on entire ecosystems. This project disentangles the mechanisms underlying climate-driven species range shifts in marine systems using the intertidal owl limpet as a case study. During the recent marine heatwaves off the Pacific coast of North America, populations at the northern range limit in northern California have expanded, with ongoing reproduction even after termination of the heatwave events. This is therefore an ideal system to explore the dynamics of natural selection that occur as species occupy new regions. Broadly, this project deepens understanding of how range shifts occur in marine systems and furthers the ability to predict future species distributions in response to climate change. The project provides research experiences for high school and undergraduate students from historically underrepresented groups by engaging with existing, demonstrably-effective programs. The investigators host leadership and skill-building workshops for senior female graduate students and engage the public in partnership with the California Academy of Sciences, Bodega Marine Lab, and San Francisco Exploratorium. Finally, the project provides training for a postdoctoral scholar and two graduate students.

Although phenomenological studies suggest that climate-associated range shifts are common in marine systems, to date, mechanistic studies of the climate-organism interactions that alter geographic distributions have largely focused on terrestrial systems. However, dispersal dynamics greatly differ in many marine systems, as currents may frequently transport planktonic larvae into new environmental regimes. This project integrates detailed demographic observations of the recent range expansion of the intertidal owl limpet, Lottia gigantea, with ecological, phenotypic, and genomic measurements of divergence across its range. Specifically, the work 1) documents phenotypic divergence in larval and juvenile traits across the zone of range expansion, 2) uses whole genome sequencing to estimate gene flow across the entire range, 3) identifies genomic patterns of selection across the zone of range expansion and through time, and 4) identifies drivers of variation in performance over latitudinal and microgeographic scales. The ability to monitor this range shift in real time, along with the suitability of this system for tracking individuals across multiple years, allows the investigators to examine the impact of selection in novel range-edge conditions at the phenotypic and genomic levels, and scale from individuals to species-level responses to ongoing environmental change.

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.