Benthic Surveys in Vatia, American Samoa: comprehensive assessment of coral demography (adult and juvenile corals) from belt transect surveys from 2020-01-23 to 2020-01-29 (NCEI Accession 0240417)

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 land-based sources of pollution, including nutrient fluxes.

The data described here result from benthic coral demographic surveys within belt transects of specified length and width for two life stages (juveniles and adults) in Vatia Bay American Samoa in 2020. The data provide information on adult coral colony counts, morphology, size, partial mortality (old and recent dead), presence and causation of disease and other compromised health conditions, including bleaching. Juvenile colony surveys include morphology and size. Taxonomic identification of adult colonies is to the species level and genus level for juveniles.

In 2020, the survey implemented was a one-stage stratified random sampling (StRS) design to assess the Vatia coral reef community. The survey domain encompassed the majority of the mapped area of reef and hard bottom habitats in the 0â30 m depth range. The stratification scheme included cardinal position (i.e., north and south) and depth (i.e., shallow: >0â6 m and mid-depth: >6â18 m). Sampling effort allocation was determined based on strata area and sites randomly located within strata. 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.

Tags: 31259, 9619un, american samoa, baseline studies, belt transect, benthic biology, benthos analysis, biology, biosphere, bleaching, coastal processes, colony - recent mortality cause, coral, coral - bleaching severity, coral - condition extent, coral - health condition, coral - morphology, coral - mortality, coral colony size and condition, coral communities, coral diseases, coral mortality, coral reef conservation program (crcp), coral reef ecology, coral reefs, corals, country/territory, earth science, in situ biological, marine biology, numeric data sets, ocean basin, oceanography, oceans, pacific ocean, pollution, rapid assessment studies, reef damage assessment, reef monitoring and assessment, shore based, status and trends assessment for lbsp impacts on reef communities in faga'alu bay and vatia bay, survey - swimmer/diver, transect monitoring, tutuila, tutuila island, united states of america, vatia bay, vatia bay (14s170w0028), zoology
Organization: National Oceanic and Atmospheric Administration, Department of Commerce