Light levels (lux) were measured at six coral reef sites in Palau during field seasons from 2021 to 2023. Loggers (Hobo Pendant, UA-002-64) were attached to threaded rods embedded in the reef using zip ties.

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Archival Copy

Version Date	Archive	Persistent Identifier (PID)	Date PID Issued
2024-05-02	Marine Biological Laboratory/Woods Hole Oceanographic Institution Library (MBLWHOI DLA)	10.26008/1912/bco-dmo.926465.1	2024-05-13

Methods & Sampling

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.

Data Processing Description

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.

BCO-DMO Processing

- 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".

Data Files

File
926465_v1_light_level_palau_reefs.csv (Comma Separated Values (.csv), 1.26 MB) MD5:c79a6d7595d3d29585720efbc287b3e6 Primary data file for dataset ID 926465, version 1

More Information about this dataset

Funding Sources

Funding Source	Award Number
NSF Division of Ocean Sciences	OCE-2048678

Deployments

None available yet

Instruments

Onset HOBO Pendant Temperature/Light Data Logger

Supplied Name: Hobo Pendant, part number UA-002-64, Onset Corp., Wareham, MA

Supplied Description:

Instrument Type

Generic Name: Onset HOBO Pendant Temperature/Light Data Logger

Acronym: Onset HOBO Pendant Temp/Light

Generic Description:

The Onset HOBO (model numbers UA-002-64 or UA-001-64) is an in-situ instrument for wet or underwater applications. It supports light intensity, soil temperature, temperature, and water temperature. A two-channel logger with 10-bit resolution can record up to approximately 28,000 combined temperature and light measurements with 64K bytes memory. It has a polypropylene housing case. Uses an optical USB to transmit data. A solar radiation shield is used for measurement in sunlight. Temperature measurement range: -20 deg C to 70 deg C (temperature). Light measurement range: 0 to 320,000 lux. Temperature accuracy: +/- 0.53 deg C from 0 deg C to 50 deg C. Light accuracy: Designed for measurement of relative light levels. Water depth rating: 30 m.

Parameters

Date and time formats are described in python strftime() syntax.

Supplied Name	Supplied description	Supplied Units	Standard Name
ISO_DateTime_Local	Date and time of measurement in ISO 8601 format; time zone: GMT+09:00. Format: %Y-%m-%dT%H:%M	unitless	ISO_DateTime_Local
ISO_DateTime_UTC	Date and time of measurement in ISO 8601 format; time zone: UTC. Format: %Y-%m-%dT%H:%MZ	unitless	ISO_DateTime_UTC
Site	Site name	unitless	site
Latitude	Site latitude; positive values = North	decimal degrees	lat
Longitude	Site longitude; positive values = East	decimal degrees	lon
Irradiance	Light level	lux	light_intensity