Nutrient and water chemistry data of Aua Reef in American Samoa from samples collected along a water quality gradient between 2022-09-13 to 2022-09-23

The data described here are from water samples collected during NOAA Pacific Islands Fisheries Science Center (PIFSC), Ecosystem Sciences Division (ESD) led fly-in Mission to Aua, American Samoa from September 8-29, 2022. Five seawater samples were collected at each site, with a total of 18 sites established across a locally known water quality gradient. The seawater samples were processed in the field, then sent to the University of Hawaii at Manoa's SOEST S-Lab to be analyzed for water chemistry and nutrients. This water quality and chemistry data includes chlorophyll-a, dissolved nitrogen, nitrate, nitrite ammonia, dissolved phosphorus, phosphate, silicate, total suspended solids, and seawater pH.

The analysis of water samples was one of several surveys conducted at the same sites across Aua reef in September 2022. Other surveys are described separately and accessible under 'Related Items' and include surveys of coral demography, benthic imagery/benthic cover, CTD casts, non-coral communities, and coral demography.

The project was funded by NOAA CRCP under project number 31303. Samples were collected by NOAA divers Bernardo Vargas-Angel, Joy Smith, and Juliette Verstaen.

Land-based sources of pollution negatively impact reef communities. Our goal here was to collect water samples and analyze them for their nutrients and chemical properties. We intend to assess whether or not a water quality gradient exists in the coral reefs of Aua.

The focal point of the mission was to establish a biological and water quality and pH baseline for Aua reef. This work was aimed at identifying measurable spatial differences in the structure and composition of the benthic and coral community at Aua that can be explained by measurable spatial patterns of water quality (nutrients and sediments) and water chemistry (pH). This work is of fundamental importance for the development of the Aua Watershed Management Plan, and will enable Federal and jurisdictional resource managers to more effectively assess the effectiveness of watershed management actions reducing land-based pollution and impacts to the adjacent coral reef ecosystems.

NOAA Coral Reef Conservation Program (CRCP) funds research under the Land-Based Sources of Pollution. This mission (Project number 31303) sought out to examine the impacts of LBSP on reef communities (coral and non-coral) in Aua, a high priority watershed in American Samoa. This mission builds on prior assessment and monitoring surveys of benthic reef communities conducted in Faga'alu and Vatia bays in 2012, 2015, and 2022 to address National and Jurisdictional goals to reduce the impacts of LBSP in local priority watersheds. Together with periodic monitoring, this coral reef community baseline for Aua reef will allow scientists to quantify temporal changes in the condition and integrity and enable Jurisdictional and Federal resource managers to make informed decisions pertaining to the protection and preservation of critical habitats. The overall effort required to evaluate the effectiveness of management strategies is significant and requires close coordination between local and Federal efforts.

This entity contains definitions for columns of water quality and water chemistry data includes chlorophyll-a, dissolved nitrogen, nitrate, nitrite ammonia, dissolved phosphorus, phosphate, silicate, total suspended solids, and seawater pH.

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.

American Samoa

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

The ESD welcomes the opportunity to collaborate on research issues contributing to the scientific basis for better management of marine ecosystems. The 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 Coral Reef 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.

Example:

Ecosystem Science Division; Pacific Islands Fisheries Science Center, 2023: Effects of Nutrients on Water Chemistry of Aua Reef in American Samoa from Water Samples collected in 2022 along a water quality gradient, https://www.fisheries.noaa.gov/inport/item/68095

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For the water chemistry samples (pH), temperature and salinity data at appropriate depth are extracted and linked with each water sample. PH sensors were used at time of water sample, and temperature and salinity data were extracted from CTD data at reef depth.

For the nutrient samples, are values were derived in the laboratory following standard procedures and were completed by the S-Lab at the University of Hawaii at Manoa

Accuracy of laboratory analysis is explained in detail in Dickson et al (2007).

Accuracy of measurements coming from 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;

Since the carbonate system can vary on a diel scale and not all samples are taken at the exact same time of day, considering the time a sample was taken may be important for some analyses. However, because all samples are taken between 8:00 AM and 12:00 PM, variation due to diel change is expected to be small.

Obviously erroneous data have been removed from the final dataset. Missing values are indicated with a n/a.

The same methods of data collection are used each time a water sample is collected. Pressure, depth, temperature, and salinity are routinely included in the observation dataset. The data are very consistent, sample collection and processing protocols are adhered to very rigorously, both in the field and in the lab.

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

The data is captured in several locations: files stored on the PIFSC network. The PIFSC network is maintained and regularly backed up by PIFSC ITS.

PIFSC Ecosystem Sciences Division (ESD) assembles water chemistry information from discrete seawater samples analyzed for pH. The carbonate system is influenced by seawater salinity, temperature, pressure, and the dissolved nutrients silicate (SiO44-) and phosphate (PO43-).

All carbonate system collection and measurement methodologies follow the protocols accepted by the greater scientific community and outlined in Dickson et al. (2007)

Sites were selected randomly along a water quality gradient established by local knowledge.