Table of Contents

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

Data were collected from 6 sites located in the Republic of Palau from November 2021 to May 2023. Threaded rods (316 stainless steel, 1/4-20 size) were driven into dead coral or sand using a hammer or by hand. Duplicate loggers (Hobo Pendants) were attached to the top of rods at each site. Light loggers were only deployed for the duration of field seasons, because biofouling was expected to decrease the accuracy of light loggers over longer deployments. Irradiance (lux) was measured every 30 minutes.

Extreme light values were removed (i.e., measurements recorded before or after deployment at our sites, including light levels in the lab or on the boat). Measurements from our 6 sites were collated into a single table, with each row representing one sampling time.

- Created a site locations table, "site_locations.csv", using the site latitudes and longitudes provided by PI by email.
- Converted latitude and longitude values from degrees and decimal minutes to decimal degrees, and rounded to 5 decimal places.
- Imported original file "Light_all sites_2021-2023.csv" into the BCO-DMO system.
- Marked "NaN" as a missing data value (missing data are blank/empty in the final CSV file).
- Unpivoted the table to create a new column for "Site" and a column for "Irradiance".
- Converted date/time field to ISO 8601 format (local).
- Created a date/time column for UTC.
- Added columns for Latitude and Longitude to the primary data table by joining to the site locations table.
- Sorted data by Site name and then date/time.
- Saved the final file as "926465_v1_light_level_palau_reefs.csv".

NSF Award Abstract:
Coral reefs host thousands of marine species, help protect coastlines from storm damage, generate tourism, and house fish used for human consumption. However, corals are vulnerable to increasing water temperatures, which can lead to coral death. One way for reefs to survive in warming oceans is for corals that are well-suited to warmer waters to repopulate reefs that have less temperature-tolerant individuals. For this strategy to succeed, however, the more temperature-tolerant corals need to be able to disperse to and survive in these different environments. This project takes advantage of reef systems in the Pacific nation of Palau that naturally experience a wide range in temperatures across short geographic distances. Using cutting-edge ecological and genomic techniques, the team of investigators is directly testing whether young corals from Palau’s warmest reefs can successfully be carried by ocean currents to Palau’s currently cooler reefs and subsequently survive and thrive in these habitats. Given the relevance of this research for the local ecology, the team is disseminating results to the Palauan government through a written report in conjunction with Palauan scientists who are interning with the team, and to the Palauan people through public presentations. As part of this work, the investigators are maintaining a blog and are organizing a music-lecture series combining dance, music, and science to promote awareness of the coral reef crisis across English and Spanish-speaking communities in the US. Results from this project are informing restoration and conservation practices of the Coral Conservation Consortium as well as other efforts worldwide.

A major question in evolutionary biology is how plasticity and adaptation interact to influence survival under novel environments. Understanding these processes is increasingly important as rising temperatures associated with climate change influence species globally. For marine organisms with pelagic larval phases, including reef-building corals, the post-settlement period constitutes a critical bottleneck for adaptation and plasticity, with the added complexity that the conditions experienced and time spent as larvae can incur carryover effects. This project leverages reefs in Palau that span a steep environmental gradient to study how environmental variation drives selection and plasticity and to examine if dispersal between reefs limits success across habitats due to carryover effects. The investigators are testing the overarching hypothesis that corals from warmer and more variable environments are adapted to warmer temperatures and exhibit increased plasticity, but that dispersal between reefs incurs a fitness cost. The team integrates field and molecular techniques to: 1) investigate the degree of selection occurring on warmer and more variable reefs, 2) test whether corals transplanted to more variable environments improve their thermal tolerance through developmental plasticity, and 3) examine whether delays in metamorphosis required for dispersal across reefs comes at a fitness cost due to carryover effects.

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.