National Coral Reef Monitoring Program: Diel seawater carbonate chemistry observations from a suite of instrumentation deployed at coral reef sites at Tutuila Island, American S...

The ocean acidification diel suite is an autonomous instrument package that measures diel variability in coral reef seawater carbonate chemistry. Diel suite surveys are conducted by the NOAA Pacific Islands Fisheries Science Center (PIFSC), Ecosystem Sciences Division (ESD) within coral reef ecosystems across the Pacific Islands Region as part of the NOAA National Coral Reef Monitoring Program (NCRMP). The data provided in this data set are from diel suites deployed at select sites at Tutuila Island in March 2015 and June - July 2018, during the ESD-led NCRMP missions to American Samoa.

Diel suites were deployed on the reef for at least 24 hours to measure in-situ salinity, temperature, pressure, pH, current direction and magnitude, and dissolved oxygen (starting 2018). Seawater samples were also collected for laboratory analyses of dissolved inorganic carbon (DIC) and total alkalinity (TA). Components of the carbonate system--including pH, pCO2 (partial pressure of carbon dioxide), and aragonite saturation state--are calculated from DIC, TA, temperature, salinity and pressure. Each diel suite typically consisted of: 1 SBE-19plus CTD sensor, 1 Nortek Acoustic Doppler Current Profiler (ADCP), 1 Satlantic SeaFET Ocean pH sensor, and up to 9 Programmable Underwater Collectors (PUCs), each of which collected 1 water sample at 3- or 4-hour intervals. Starting 2018, 1 SBE-43 oxygen sensor is tethered to the CTD sensor for diel surveys. Diel surveys from 2019 also incorporate stand-alone PAR and DO loggers however they have yet to be conducted in American Samoa. Instruments deployed, samples collected, and sample intervals are recorded in the summary file enclosed with the data package, and exceptions to the standard diel suite are also noted.

Manual seawater sampling and other National Coral Reef Monitoring Program (NCRMP) field monitoring efforts are limited to daylight hour operations. As a result, these data sets do not capture full 24-hour variability in coral reef physical and chemical environments. The ocean acidification diel suite was developed to increase the temporal resolution and coverage of oceanographic and carbonate chemistry measurements and contextualize daytime sampling within the full diel cycle.

An SBE-43 oxygen sensor was tethered to the SBE-19plus CTD sensor starting in 2018. Data from the diel surveys in 2016 only include CTD and water quality data, without dissolved oxygen.

The NOAA National Coral Reef Monitoring Program (NCRMP) details a long-term approach to provide an ecosystem perspective via monitoring climate, fish, benthic, and socioeconomic variables in a consistent and integrated manner. The NCRMP is intended to coordinate various NOAA Coral Reef Conservation Program (CRCP) biological, physical, and human dimensions activities into a cohesive NOAA-wide effort. Through the implementation of the NCRMP, NOAA will be able to clearly and concisely communicate results of national-scale monitoring to national, state, and territorial policy makers, resource managers, and the public on a periodic basis.

NCRMP provides a framework for conducting sustained observations of biological, climate, and socioeconomic indicators at 10 priority coral reefs across the U.S. and its territories. This integrated approach consolidates monitoring of coral reefs under a uniform method in the Pacific, Atlantic, Caribbean, and the Gulf of Mexico for the first time. NCRMP is funded by the CRCP and supported by NOAA Fisheries, NOAA National Centers for Coastal Ocean Science (NCCOS), NOAA's Atlantic Oceanographic & Meteorological Laboratory (AOML), NOAA Coral Reef Watch, and many other partners.

The Pacific Islands Fisheries Science Center (PIFSC), Ecosystem Sciences Division (ESD) at NOAA Fisheries is leading in-situ climate monitoring in the U.S. Pacific Islands Region as part of the ongoing Pacific Reef Assessment and Monitoring Program (RAMP). The climate component of NCRMP in the Pacific provides a comprehensive view of climate change impacts on coral reef ecosystems and helps identify areas of resilience and vulnerability. The key indicators used to identify and monitor climate-driven trends include 1) thermal stress caused by changes in sea temperature, 2) ocean acidification resulting from changes in carbonate chemistry, and 3) ecological impacts by collecting data on coral growth rates, erosion, and community structure to understand the impacts of thermal stress and ocean acidification on the ecosystem. Each year, ESD scientists work closely with CRCP and partners during Pacific RAMP missions to collect data using moored oceanographic (subsurface temperature recorders) and ecological (calcification accretion units [CAUs] and autonomous reef monitoring structures [ARMS]) instruments stationed at fixed sites in the Pacific Ocean, and water samples collected by divers. The in-situ data and satellite-based observations are also used in modeling efforts. Innovative analysis techniques are used to develop products that give fellow scientists, managers, decision makers and the public a better understanding of a region's resources and how they are changing over time.

Initially published in 2019 with data collected in 2015. Updated in 2021 with data collected in 2018.

CTD data include conductivity, temperature, and pressure observations with calculated depth, salinity, and density.

Water samples are analyzed for dissolved inorganic carbon (DIC) and total alkalinity (TA). pH, partial pressure of carbon dioxide, and aragonite saturation state are mathematically derived from TA and DIC values using temperature, salinity, and pressure data from the CTD.

pH data are the mean of a burst of 30 measurements collected every 5 minutes.

Current magnitude (meters/second) and direction (degrees) data are typically binned into 1-m height bins represented by the height of each bin above the sensor on the seafloor, but smaller bin sizes (0.25 - 0.5m) are used for shallower deployments.

Dissolved oxygen data was included as of 2021, after the SBE-43 DO sensor was tethered to the CTD sensor from 2018.

While every effort has been made to ensure that these data are accurate and reliable within the limits of the current state of the art, NOAA cannot assume liability for any damages caused by errors or omissions in the data, nor as a result of the failure of the data to function on a particular system. NOAA makes no warranty, expressed or implied, nor does the fact of distribution constitute such a warranty.

Tutuila Island, American Samoa

Associated REA Site TUT-74 on Tutuila Island, American Samoa.

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NOAA Ecosystem Sciences Division (ESD) Data Sharing Recommendations, version 9.0 updated August 12, 2015:

ESD welcomes the opportunity to collaborate on research issues contributing to the scientific basis for better management of marine ecosystems. ESD has a very diverse set of field activities that generates large volumes of data using an array of data collection protocols.

The following recommendations are for your consideration as you use this data:

1) Data analyses should take all field exigencies into account. The most effective way to do this would be active collaboration with ESD principal investigators.

2) In all presentations, product releases, or publications using data generated by ESD, proper acknowledgement of both ESD and the individuals responsible for data collection is expected. Citing the DOI (if available) is preferred, a non-DOI example is listed below.

3) If you collect or generate data for the same study areas, ESD requests that you share relevant information on complimentary data collections.

4) Those receiving data are strongly urged to inform the ESD Data Management Team of any errors and discrepancies that are discovered during the course of using these data. They are further urged to bring to the attention of the Team all problems and difficulties encountered in using these data. This information is necessary in order to improve the collections and to facilitate more efficient and economical data processing and retrieval. The users are asked to supply copies of any missing data that may be located, and to provide information as to significant subsets and special aggregations of data that are developed in using the material provided.

Example citation:

"This publication makes use of data products provided by the Ecosystem Sciences Division (ESD), Pacific Islands Fisheries Science Center (PIFSC), National Marine Fisheries Service (NMFS), National Oceanic and Atmospheric Administration (NOAA), with funding support from the NOAA Coral Reef Conservation Program (CRCP). The analysis and interpretations presented here are solely that of the current authors.”

Data can be accessed online via the NOAA National Centers for Environmental Information (NCEI) Ocean Archive.

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Please cite PIFSC Ecosystem Sciences Division (ESD) when using the data.

Suggested citation:

Ecosystem Sciences Division; Pacific Islands Fisheries Science Center, 2021: National Coral Reef Monitoring Program: Diel seawater carbonate chemistry observations from a suite of instrumentation deployed at coral reef sites at Tutuila Island, American Samoa in 2015 and 2018, https://www.fisheries.noaa.gov/inport/item/54928.

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Raw data are downloaded from the instruments, processed in R, and migrated to the PIFSC Oracle database.

Water sample data is stored in an MS Access database.

Seawater carbonate chemistry at the benthos is dynamic and driven by physical and biological processes occurring at time scales of minutes to days. The measurements and analyses from this instrument suite is representative of the water column chemistry at the time of measurement, but this highly variable environment allows for a fairly wide distribution of measured values.

Water samples: accuracy of seawater carbonate chemistry laboratory analysis is explained in detail in Dickson et al (2007), SOP #2: Determination of total dissolved inorganic carbon in sea water, and SOP #3b: Determination of total alkalinity in sea water using an open-cell titration.

Satlantic SeaFET Ocean pH sensor: measurement range: 6.5-9.0 pH; salinity range: 2-40 psu; accuracy: +/- 0.05 pH; precision: better than 0.001 pH; resolution: 0.0001 pH; stability: 0.005 pH/mo

SBE-19plus CTD sensor:

Conductivity - measurement range: 0-9 S/m; accuracy: +/- 0.0005 S/m; stability: 0.0003 S/m per month; resolution: 0.00005 S/m;

Temperature - measurement range: -5-35 deg C; accuracy: +/-0.005 deg C; stability: 0.0002 deg C per month; resolution: 0.0001 deg C;

Pressure - measurement range: 0-600 m; accuracy: +/- 0.1%; stability: +/- 0.1%; resolution: 0.002%

Nortek Acoustic Doppler Current Profiler 1MHz: Profiling range: 12-25 m; accuracy: +/- 1%

SBE-43 oxygen sensor: Measurement range: 120% surface saturation; accuracy: +/- 2% of saturation; stability: 0.5% per 1000 hours

For some deployments, paired water samples are collected simultaneously at the benthos and 1.5 meters above the seafloor.

The entire suite of instrumentation is deployed during diel surveys; however, various issues can occur with any one or several of the instruments during the deployment thereby limiting the data recovered.

While PUCs are programmed to collect water on this regular sampling schedule, issues with the pumps can occasionally result in missing samples for some of the time steps.

Refer to the summary file enclosed with the data package for details.

Redundant data are collected to ensure accuracy of the methods/instrumentation. pH is captured from the discrete water samples and pH sensor. Pressure is captured by the ADCP and the CTD. Temperature is captured by the pH sensor and the CTD, For some deployments, paired water samples are collected simultaneously at the benthos and 1.5 meters above the seafloor.

All analyzed samples and measured values are included. NULL values in the data, where they exist, indicate that the observation/analysis was not conducted for the sample record where it appears.

The data are very consistent, sample collection and processing protocols detailed in Dickson et al (2007) are adhered to rigorously, both in the field (SOP #1) and in the laboratory (SOP #2 and #3b).

The data is quality controlled by NOAA PIFSC Ecosystem Sciences Division (ESD) personnel after the data is downloaded from the instruments, after it is migrated to the database, and once again when the data are submitted to the NOAA National Centers for Environmental Information.

NOAA Pacific Marine Environmental Laboratory (PMEL) conducts quality assurance and quality control on their seawater analyses according to protocols #2 and #3b in Dickson et al (2007).

The data is captured in several locations: files stored on the cruise server during the mission and the PIFSC network, and data are imported into the PIFSC Oracle database. The cruise server is regularly backed up by the cruise data manager while at sea, and the PIFSC network and Oracle database are maintained and regularly backed up by PIFSC ITS.

The ocean acidification diel suite is a collection of instruments deployed by SCUBA divers onto the seafloor that makes autonomous measurements and collects seawater samples. For a typical deployment, the diel suite consists of: 1 Sea Bird Electronics (SBE)-19plus CTD, 1 Nortek Acoustic Doppler Current Profiler (ADCP), 1 Satlantic SeaFET Ocean pH sensor, and up to 9 Programmable Underwater Collectors (PUCs), where each PUC collects 1 water sample at a 3- or 4-hour interval over a minimum 24-hour period. All instruments are weighted or zip-tied to rubble on the seafloor, or both, to secure the position of the instrumentation for the duration of the deployment. An oxygen sensor was included in the diel suite deployment from 2018.