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    • Benthic Surveys in Vatia, American Samoa: benthic cover derived from analysis of benthic images collected during belt transect surveys of coral demography in 2015 and 2020

    Metadata Updated: December 13, 2025

    Jurisdictional managers have expressed concerns that nutrients from the village of Vatia, Tutuila, American Samoa, are having an adverse effect on the adjacent coral reef ecosystem. Excess nutrient loads promote increases in algal growth that can have deleterious effects on corals, such as benthic algae outcompeting and overgrowing corals. Nitrogen and phosphorus can also directly impact corals by lowering fertilization success, and reducing both photosynthesis and calcification rates. Land-based contributions of nutrients come from a variety of sources; in Vatia the most likely sources are poor wastewater management from piggeries and septic systems.

    NOAA scientists conducted benthic surveys to establish a baseline against which to compare changes in the algal and coral assemblages in response to nutrient fluxes.

    The benthic cover data described here were generated from the quantitative analysis of photoquadrat benthic images using image analysis software, whereby random points are projected on each image and the benthic elements falling directly underneath each point are identified. The images were collected at 18 and 24 stratified randomly selected sites in 2015 and 2020 respectively, during belt transect surveys of coral demography by the NOAA Ecosystem Sciences Division (ESD; former Coral Reef Ecosystem Program CREP). Five of the 18 sites surveyed in 2015 were resurveyed periodically in 2016 (January, March, June, September, and December) to assess any short-term temporal changes in the benthic composition.

    The benthic cover data can be accessed online via the NOAA National Centers for Environmental Information (NCEI) Ocean Archive. The benthic images and coral demography data are described and archived separately.

    Access & Use Information

    License: No license information was provided. If this work was prepared by an officer or employee of the United States government as part of that person's official duties it is considered a U.S. Government Work.

    Downloads & Resources

    Dates

    Metadata Date December 3, 2025
    Metadata Created Date October 19, 2024
    Metadata Updated Date December 13, 2025
    Reference Date(s) 2022 (publication)
    Frequency Of Update notPlanned

    Metadata Source

    Harvested from NMFS PIFSC

    Other Data Resources

    Additional Metadata

    Resource Type Dataset
    Metadata Date December 3, 2025
    Metadata Created Date October 19, 2024
    Metadata Updated Date December 13, 2025
    Reference Date(s) 2022 (publication)
    Responsible Party (Point of Contact, Custodian)
    Contact Email
    Guid gov.noaa.nmfs.inport:31611
    Access Constraints Cite As: Pacific Islands Fisheries Science Center, [Date of Access]: Benthic Surveys in Vatia, American Samoa: benthic cover derived from analysis of benthic images collected during belt transect surveys of coral demography in 2015 and 2020 [Data Date Range], https://www.fisheries.noaa.gov/inport/item/31611., Access Constraints: None, Use Constraints: 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 Vatia, American Samoa: benthic percent cover derived from analysis of benthic images collected during belt transect surveys of coral demography in 2015 and 2020. NOAA National Centers for Environmental Information. https://www.fisheries.noaa.gov/inport/item/31611, Distribution Liability: 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.
    Bbox East Long -170.66666666667
    Bbox North Lat -14.24305555556
    Bbox South Lat -14.25138888889
    Bbox West Long -170.67555555556
    Coupled Resource
    Frequency Of Update notPlanned
    Harvest Object Id f2aecb00-bd45-433d-935c-ff13004d0150
    Harvest Source Id c0beac72-5f43-4455-8c33-1b345fbc2dfe
    Harvest Source Title NMFS PIFSC
    Licence NOAA provides no warranty, nor accepts any liability occurring from any incomplete, incorrect, or misleading data, or from any incorrect, incomplete, or misleading use of the data. It is the responsibility of the user to determine whether or not the data is suitable for the intended purpose.
    Lineage The methodology to analyze benthic imagery using CoralNet to derive benthic cover values. The data described here were derived from the analysis of benthic images collected along photo-quadrat surveys by the NOAA Ecosystem Sciences Division (ESD): In 2015 photo quadrat images were taken every meter from the 1-m to the 15-m mark along TWO, 18-m transects per site (n = 30 images). In 2020 photo quadrat images were taken every meter from the 1-m to the 30-m mark along one 30-m transect line (n = 30 images).
    Metadata Language eng
    Metadata Type geospatial
    Old Spatial {"type": "Polygon", "coordinates": [[[-170.67555555556, -14.25138888889], [-170.66666666667, -14.25138888889], [-170.66666666667, -14.24305555556], [-170.67555555556, -14.24305555556], [-170.67555555556, -14.25138888889]]]}
    Progress onGoing
    Spatial Data Service Type
    Spatial Reference System
    Spatial Harvester True
    Temporal Extent Begin 2015-11-02
    Temporal Extent End 2015-11-12

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