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Ridge to Reef in American Samoa

Coral reef conservation is not restricted to the water. Coastal development, deforestation, agricultural runoff, and oil and chemical spills introduce pollution into coral reef ecosystems. Land-based sources of pollution affect coral growth and reproduction, disrupt overall ecosystem function, and lead to disease and death. NOAA uses a “ridge to reef” approach to address this connection.

The island of Tutuila in American Samoa
The island of Tutuila in American Samoa, viewed from the NOAA Ship Hi'ialakai. (NOAA Fisheries, Kaylyn McCoy)

Coral reefs in American Samoa are in good condition according to NOAA’s National Coral Reef Monitoring Program. The U.S. Geological Survey determined that coral reefs in American Samoa protect over 1050 people and more than $46.5 million in infrastructure from flooding related to “10-year” storms. To preserve these ecosystems, NOAA’s Coral Reef Conservation Program and the National Centers for Coastal Ocean Science recently funded two local studies on land-based sources of pollution.

Excess Nutrients in Vatia Bay, American Samoa

Vatia Bay sits on the north side of Tutuila, the largest and most populated island of American Samoa. The bay is surrounded by the village of Vatia and the National Park of American Samoa. Of local concern are the effects of nutrients from household sewage and small agricultural operations on the water quality of coral ecosystems in the bay.

Scientists completed a study to accomplish the following:

  • Measure the nutrients in the bay,
  • Establish a baseline of nutrients for future monitoring,
  • Link nutrients to possible sources,
  • Determine if human waste is reaching the bay, and
  • Connect nutrients with signs of coral reef health.

Results of the study show that human waste is entering Vatia Bay, and water quality likely affects coral reef health.

A Baseline Chemical Contaminants Assessment of Sediment from the Nu'uuli Pala Lagoon, American Samoa

The Nu'uuli Pala Lagoon is located on the south shore of Tutuila near the most populous area of the island. The villages of Nu'uuli, Tafuna, Faleniu, Malaeimi, and Mesepa, representing 28 percent of the total population of American Samoa, drain into the lagoon. The lagoon is also just north of the Pago Pago International Airport. In this study, scientists collected sediment samples to analyze chemical contamination in the lagoon.

The study concluded that

  • Contaminant levels in Nu'uuli Pala Lagoon are low compared to other locations studied by NOAA’s National Status and Trends Program,
  • Contaminant levels in the lagoon are similar to those in nearby Faga'alu Bay,
  • DDT, an insecticide, exceed established minimums in Nu'uuli Pala Lagoon,
  • Levels of PBDEs, which are used as flame retardants, are higher in Nu'uuli Pala Lagoon than in other US coastal areas with a similar number of people, and
  • Levels of elements like arsenic, copper, and nickel are higher than established minimums.

As NOAA gathers more information about land-based sources of pollution in American Samoa and other states and territories with coral reef ecosystems, scientists can more effectively decrease the effects and ensure that coral reefs remain productive and thriving.

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