Benthic surveys along a water quality gradient in Aua, American Samoa: benthic images collected during belt transect surveys in 2022

This metadata record describes the imagery collected in 2022 of Aua Reef, American Samoa by the Ecosystem Sciences Division (ESD) of NOAA, funded by the Coral Reef Conservation Program (CRCP), to study effects of land-based source pollution by establishing biological, physical, and chemical baselines.

In September 2022, NOAA scientists conducted benthic survey protocols at 18 study sites in Aua, American Samoa. The surveys implemented a one-stage stratified random sampling (StRS) design and the survey domain encompassed the majority of the mapped area of reef and hard bottom habitats in the 0 to 6 m depth range. Photoquadrat benthic images were collected along belt transect surveys of coral demography according to protocols established by NOAA National Coral Reef Monitoring Program (NCRMP) in 2015.

Thirty images were collected along one, haphazardly laid, 30-m transects. Still photographs were collected to record the benthic community composition at predetermined points along belt transect with a high-resolution digital camera mounted on a pole. Photographs were taken every 1 m from the 1 m to the 30 m mark. This work generates 30 photographs per site, which are later analyzed by ESD staff and partners using the computer program CoralNet. This analysis is the basis for estimating benthic cover and composition at each site, which is documented and archived separately.

The StRS design effectively reduces estimate variance through stratification using environmental covariates and by sampling more sites rather than more transects per site. Therefore, site-to-site comparisons should proceed with caution.

The focal point of this project was to establish a biological, water quality, and carbonate chemistry baseline for Aua reef. This work aims 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 carbonate chemistry (pH and Alkalinity). 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.

The imagery described in this metadata record is the source imagery analyzed to produce benthic cover data, which is archived and documented separately (see 'Related Items' below)

This baseline assessment for land-based sources of pollution on Aua reef is part of a larger Coral Reef Conservation Program (CRCP) funded project ID 31303: "Linking watershed management activities to reef health in American Samoa", and builds upon prior baseline and status and trends assessments conducted in 2012, 2015, and 2020 in Faga'alu Bay (U.S. Task Force watershed priority site) and Vatia (Territorial priority watershed) to address National and Jurisdictional goals to reduce land-based sources of pollution impacts in coral reef ecosystems. See 'Related Items' for links to metadata records imagery of those missions.

Data was generated from benthic surveys of Aua reef to establish a comprehensive biological baseline, for land-based sources of pollution impacts on benthic composition and coral demographics. These efforts feed into the higher-level CRCP objectives by establishing an in-situ tracking system to assess the effects of management and mitigation strategies and activities in the target watersheds to reduce land-based sources of pollution impacts on coral reefs.

Conductivity-Temperature-Depth (CTD) profiles as well as water samples were also collected as part of this baseline assessment for the analysis of particulate and dissolved nutrients, total suspended solids, chlorophyll-a, and seawater pH and Alkalinity. These data are documented and archived separately (see 'Related Items' below).

Raw data include 30 benthic photographs per survey site (some survey sites may have less than 30 images). Included in the archive package is a list of survey sites, including site id, location (latitude/longitude), and survey date, where photoquads were collected. The file naming convention for each photo/image is [SITE]_[YEAR]_[TRANSECT]_[PHOTO_NUMBER].JPG (for example: TUT-903_2012_A_01.JPG).

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.

Aua reef, Tutuila, American Samoa

Not applicable

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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, link in the Distribution Information.

None

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

Example

Cite as: Vargas-Angel, Bernardo; Ecosystem Sciences Division; Pacific Islands Fisheries Science Center (2022). Benthic Surveys in Aua, American Samoa: benthic photoquadrat images collected during belt transect surveys 2022. [access date]

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None

PIFSC network/file system:

T:\Cruise\CruiseData\MP2206\Optical\TUT\REA\BENTHIC

Handheld GPS units were used to locate random sites and mark site locations. Images captured from the camera may not contain a clear depiction of the benthos due to a number of confounding factors, including the angle of the camera lens in relation to the benthos, the distance between the camera lens and the benthos, and water turbidity.

Image data include 30 benthic photographs per survey site. Appropriate site level image grouping should include all 30 images.

Not applicable

Site GPS location and depth are appropriately collected to allow spatiotemporal comparisons.

Complete; photoquads were taken at all sites surveyed. On occasions instrument malfunction or sea conditions may preclude the collection of 30 benthic images per site.

Hard bottom habitats including backreef, reef flat, and forereef were surveyed.

Only shallow water (0 to 30 meter depth range) hard-bottom habitats are surveyed. The survey sites were randomly selected using a systematic process based on available habitat and bathymetric data. Although efforts are made to include broad spatial coverage of surveys at each island, weather conditions and other environmental constraints may have prevented the team from surveying exposed reef areas.

The same methods of data collection were used at each surveyed site.

Instrumentation and camera setting are updated periodically to improve image quality. The photos are reviewed by the diver for accuracy and usability. The data management team also uses a optical validation script to re-name photos and enforce several validation checks. Images are color corrected prior to analysis.

NOAA IRC and NOAA Fisheries ITS resources and assets.

Benthic photographs were collected during belt transect surveys of corals by the NOAA Ecosystem Sciences Division (ESD) following the same protocol to that established by the NOAA National Coral Reef Monitoring Plan (NCRMP).

BV ADD / MENTION THE COMPLEMENTARY IMAGERY / SITES COLLECTED AND HOW THEY WERE SELECTED