As part of the USGS Coral Reef Project, the USGS is working on Tutuila with its partners: 1.) in Faga’alu Bay to better understand the impacts of land-based pollutants on the coral reefs, and 2.) on the north coast to help determine the effects of circulation on nearshore waters.
Overview
Tutuila encompasses 140 square kilometers (54 square miles) and is the largest and main island of American Samoa, an organized unincorporated territory of the United States. The island is located in the central south Pacific Ocean, about 4,000 kilometers (2,500 miles) northeast of Australia. Formed from Pliocene-age volcanic rocks, Tutuila has a rugged southwest-northeast trending mountain ridge that hugs the northern part of the island and reaches an elevation of 653 meters (2,142 feet). The southern part of the island, however, is relatively flat. Tutuila boasts nearly 100 kilometers (62 miles) of coastline, with the deep embayment of Pago Pago Harbor on the south shore nearly dividing the island into two parts.
Tutuila’s nearshore coral reefs are home to more than 250 different species of coral, including hard “table” corals nearly 3 meters (10 feet) in diameter. Impacts from poor land-management practices are threatening the health of these ecosystems. Marine protected areas include the Tutuila unit of the National Park of American Samoa on the northern coast and Fagatele Bay National Marine Sanctuary on the southern tip of the island.
Motivation
Human activity has significantly increased the volume of land-based pollution (sediment, nutrients, and contaminants) along much of Tutuila’s southern coastline. These human activities are related primarily to land-management practices, including urban development, wastewater discharge, and poor land use. Because of these land-based pollution impacts to the coral reefs, the U.S. Coral Reef Task Force (USCRTF) designated Faga’alu Bay on the south shore of Tutuila as the third USCRTF Priority Study Area. The USGS is working with San Diego State University, NOAA, and other U.S. Coral Reef Task Force (USCRTF) partners to better understand the impacts of these land-based pollutants on the coral reefs in Faga’alu Bay.
Starting in the late 2000s, a significant outbreak of Crown-of-Thorns (COTS) sea stars (Acanthaster planci) began on the western side of Tutuila and decimated many of the coral reefs. This COTS outbreak has now spread to the north coast, and is threatening National Park waters between Fagasa and Afono Bays. In addition to our studies in Faga’alu Bay on the south shore, the USGS is working with the National Park Service on the north coast of the island to help determine the effects of circulation on the nearshore waters, and how it may influence the spread of COTS.

Tutuila is the largest and main island of American Samoa in the south Pacific Ocean, northeast of Australia. It is one of the many study locations of the USGS Coral Reef Project.
Reef Hydrodynamics and Sediment Processes
Reef Resource Assessments - Planning for the Future
Role of Reefs in Coastal Protection
Hydrogeology and Reef Health
Climate Change and Land-use Histories
Below are data releases associated with this project.
Projected flooding extents and depths based on 10-, 50-, 100-, and 500-year wave-energy return periods, with and without coral reefs, for the States of Hawaii and Florida, the Territories of Guam, American Samoa, Puerto Rico, and the U.S. Virgin Islands,
Still-image frame grabs and benthic habitat interpretation of underwater video footage, March 2014, Faga'alu Bay, Tutuila Island, American Samoa
Underwater Video Footage, March 2014, Faga`alu Bay, Tutuila Island, American Samoa
Below are multimedia items associated with this project.
Below are publications associated with this project.
The value of US coral reefs for flood risk reduction
Rigorously valuing the role of U.S. coral reefs in coastal hazard risk reduction
Meteorologic, oceanographic, and geomorphic controls on circulation and residence time in a coral reef-lined embayment: Faga’alu Bay, American Samoa
Coastal circulation and water-column properties in the National Park of American Samoa, February–July 2015
Benthic habitat map of U.S. Coral Reef Task Force Faga‘alu Bay priority study area, Tutuila, American Samoa
The effectiveness of coral reefs for coastal hazard risk reduction and adaptation
From ridge to reef—linking erosion and changing watersheds to impacts on the coral reef ecosystems of Hawai‘i and the Pacific Ocean
The use (and misuse) of sediment traps in coral reef environments: Theory, observations, and suggested protocols
Rising sea level may cause decline of fringing coral reefs
Numerical modeling of the impact of sea-level rise on fringing coral reef hydrodynamics and sediment transport
Science-Based Strategies for Sustaining Coral Ecosystems
Temporal variability in chlorophyll fluorescence of back-reef corals in Ofu, American Samoa
Below are partners associated with this project.
- Overview
As part of the USGS Coral Reef Project, the USGS is working on Tutuila with its partners: 1.) in Faga’alu Bay to better understand the impacts of land-based pollutants on the coral reefs, and 2.) on the north coast to help determine the effects of circulation on nearshore waters.
Overview
IKONOS satellite image of Tutuila Tutuila encompasses 140 square kilometers (54 square miles) and is the largest and main island of American Samoa, an organized unincorporated territory of the United States. The island is located in the central south Pacific Ocean, about 4,000 kilometers (2,500 miles) northeast of Australia. Formed from Pliocene-age volcanic rocks, Tutuila has a rugged southwest-northeast trending mountain ridge that hugs the northern part of the island and reaches an elevation of 653 meters (2,142 feet). The southern part of the island, however, is relatively flat. Tutuila boasts nearly 100 kilometers (62 miles) of coastline, with the deep embayment of Pago Pago Harbor on the south shore nearly dividing the island into two parts.
Tutuila’s nearshore coral reefs are home to more than 250 different species of coral, including hard “table” corals nearly 3 meters (10 feet) in diameter. Impacts from poor land-management practices are threatening the health of these ecosystems. Marine protected areas include the Tutuila unit of the National Park of American Samoa on the northern coast and Fagatele Bay National Marine Sanctuary on the southern tip of the island.
Motivation
Porites and Acropora coral species in reef flat pools in the National Park of American Samoa on Ofu, Manuʻa Islands Group, American Samoa. Human activity has significantly increased the volume of land-based pollution (sediment, nutrients, and contaminants) along much of Tutuila’s southern coastline. These human activities are related primarily to land-management practices, including urban development, wastewater discharge, and poor land use. Because of these land-based pollution impacts to the coral reefs, the U.S. Coral Reef Task Force (USCRTF) designated Faga’alu Bay on the south shore of Tutuila as the third USCRTF Priority Study Area. The USGS is working with San Diego State University, NOAA, and other U.S. Coral Reef Task Force (USCRTF) partners to better understand the impacts of these land-based pollutants on the coral reefs in Faga’alu Bay.
Starting in the late 2000s, a significant outbreak of Crown-of-Thorns (COTS) sea stars (Acanthaster planci) began on the western side of Tutuila and decimated many of the coral reefs. This COTS outbreak has now spread to the north coast, and is threatening National Park waters between Fagasa and Afono Bays. In addition to our studies in Faga’alu Bay on the south shore, the USGS is working with the National Park Service on the north coast of the island to help determine the effects of circulation on the nearshore waters, and how it may influence the spread of COTS.
Sources/Usage: Public Domain. Visit Media to see details.Underwater photograph showing corals in Tāfeu Cove, National Park of American Samoa, north shore of Tutuila Island, American Samoa. - Science
Tutuila is the largest and main island of American Samoa in the south Pacific Ocean, northeast of Australia. It is one of the many study locations of the USGS Coral Reef Project.
Reef Hydrodynamics and Sediment Processes
As part of the USGS Coral Reef Project, the overall objective of this research effort is to better understand how circulation and sediment processes impact coral reefs and their adjacent coastlines.Reef Resource Assessments - Planning for the Future
We are mapping and assessing all of the important geologic and oceanographic factors to identify those coral reefs most at risk and those reefs that are potentially the most resilient and the most likely to recover from natural and human-driven impacts.Role of Reefs in Coastal Protection
We are combining ocean, engineering, ecologic, social, and economic modeling to provide a high-resolution, rigorous, spatially-explicit valuation of the coastal flood protection benefits provided by coral reefs and the cost effectiveness of reef restoration for enhancing those benefits.Hydrogeology and Reef Health
As part of the USGS Coral Reef Project, we are conducting geophysical and geochemical research to address questions about coastal groundwater-to-reef flow and coral reef health, with the goal of informing management decisions related to planning and implementing activities in priority watershed-coral reef systems.Climate Change and Land-use Histories
As part of the USGS Coral Reef Project, we are developing new and unique oceanographic and environmental archives from coral skeleton records to better understand the compounding effects of land-use and environmental change on coral reef health. - Data
Below are data releases associated with this project.
Projected flooding extents and depths based on 10-, 50-, 100-, and 500-year wave-energy return periods, with and without coral reefs, for the States of Hawaii and Florida, the Territories of Guam, American Samoa, Puerto Rico, and the U.S. Virgin Islands,
This data release provides flooding extent polygons (flood masks) and depth values (flood points) based on wave-driven total water levels for 22 locations within the States of Hawaii and Florida, the Territories of Guam, American Samoa, Puerto Rico, and the U.S. Virgin Islands, and the Commonwealth of the Northern Mariana Islands. For each of the 22 locations there are eight associated flood maskStill-image frame grabs and benthic habitat interpretation of underwater video footage, March 2014, Faga'alu Bay, Tutuila Island, American Samoa
Underwater video imagery was collected in March 2014 in the nearshore waters of Faga'alu Bay on the Island of Tutuila, American Samoa, as part of the U.S. Geological Survey Coastal and Marine Geology Program's Pacific Coral Reefs Project. This data set includes 2,119 still images extracted from the video footage every 10 seconds and an Environmental Systems Research Institute (ESRI) shapefile withUnderwater Video Footage, March 2014, Faga`alu Bay, Tutuila Island, American Samoa
Underwater video imagery was collected in March 2014 in the nearshore waters of Fagaalu Bay on the Island of Tutuila, American Samoa, as part of the U.S. Geological Survey Coastal and Marine Geology Program's Pacific Coral Reefs Project. Included here are 40 video files in .mpg format and an Environmental Systems Research Institute (ESRI) shapefile with location (navigation) points every two secon - Multimedia
Below are multimedia items associated with this project.
- Publications
Below are publications associated with this project.
The value of US coral reefs for flood risk reduction
Habitats, such as coral reefs, can mitigate increasing flood damages through coastal protection services. We provide a fine-scale, national valuation of the flood risk reduction benefits of coral habitats to people, property, economies and infrastructure. Across 3,100 km of US coastline, the top-most 1 m of coral reefs prevents the 100-yr flood from growing by 23% (113 km2), avoiding flooding to 5Rigorously valuing the role of U.S. coral reefs in coastal hazard risk reduction
The degradation of coastal habitats, particularly coral reefs, raises risks by increasing the exposure of coastal communities to flooding hazards. The protective services of these natural defenses are not assessed in the same rigorous economic terms as artificial defenses, such as seawalls, and therefore often are not considered in decision making. Here we combine engineering, ecologic, geospatialMeteorologic, oceanographic, and geomorphic controls on circulation and residence time in a coral reef-lined embayment: Faga’alu Bay, American Samoa
Water circulation over coral reefs can determine the degree to which reef organisms are exposed to the overlying waters, so understanding circulation is necessary to interpret spatial patterns in coral health. Because coral reefs often have high geomorphic complexity, circulation patterns and the duration of exposure, or “local residence time” of a water parcel, can vary substantially over small dCoastal circulation and water-column properties in the National Park of American Samoa, February–July 2015
There is little information on the oceanography in the National Park of American Samoa (NPSA). The transport pathways for potentially harmful constituents of land-derived runoff, as well as larvae and other planktonic organisms, are driven by nearshore circulation patterns. To evaluate the processes affecting coral reef ecosystem health, it is first necessary to understand the oceanographic procesBenthic habitat map of U.S. Coral Reef Task Force Faga‘alu Bay priority study area, Tutuila, American Samoa
The coral reef in Faga‘alu Bay, Tutuila, American Samoa, has suffered numerous natural and anthropogenic stresses. Areas once dominated by live coral are now mostly rubble surfaces covered with turf or macroalgae. In an effort to improve the health and resilience of the coral reef system, the U.S. Coral Reef Task Force selected Faga‘alu Bay as a priority study area. To support these efforts, the UThe effectiveness of coral reefs for coastal hazard risk reduction and adaptation
The world’s coastal zones are experiencing rapid development and an increase in storms and flooding. These hazards put coastal communities at heightened risk, which may increase with habitat loss. Here we analyse globally the role and cost effectiveness of coral reefs in risk reduction. Meta-analyses reveal that coral reefs provide substantial protection against natural hazards by reducing wave enFrom ridge to reef—linking erosion and changing watersheds to impacts on the coral reef ecosystems of Hawai‘i and the Pacific Ocean
Coral reef ecosystems are threatened by unprecedented watershed changes in the United States and worldwide. These ecosystems sustain fishing and tourism industries essential to the economic survival of many communities. Sediment, nutrients, and pollutants from watersheds are increasingly transported to coastal waters, where these contaminants damage corals. Although pollution from watersheds is onThe use (and misuse) of sediment traps in coral reef environments: Theory, observations, and suggested protocols
Sediment traps are commonly used as standard tools for monitoring “sedimentation” in coral reef environments. In much of the literature where sediment traps were used to measure the effects of “sedimentation” on corals, it is clear from deployment descriptions and interpretations of the resulting data that information derived from sediment traps has frequently been misinterpreted or misapplied. DeRising sea level may cause decline of fringing coral reefs
Coral reefs are major marine ecosystems and critical resources for marine diversity and fisheries. These ecosystems are widely recognized to be at risk from a number of stressors, and added to those in the past several decades is climate change due to anthropogenically driven increases in atmospheric concentrations of greenhouse gases. Most threatening to most coral reefs are elevated sea surfaceNumerical modeling of the impact of sea-level rise on fringing coral reef hydrodynamics and sediment transport
Most climate projections suggest that sea level may rise on the order of 0.5-1.0 m by 2100; it is not clear, however, how fluid flow and sediment dynamics on exposed fringing reefs might change in response to this rapid sea-level rise. Coupled hydrodynamic and sediment-transport numerical modeling is consistent with recent published results that suggest that an increase in water depth on the orderScience-Based Strategies for Sustaining Coral Ecosystems
Coral ecosystems and their natural capital are at risk. Greenhouse gas emissions, overfishing, and harmful land-use practices are damaging our coral reefs. Overwhelming scientific evidence indicates that the threats are serious, and if they are left unchecked, the ecological and social consequences will be significant and widespread. Although the primary stressors to coral ecosystems are known, scTemporal variability in chlorophyll fluorescence of back-reef corals in Ofu, American Samoa
Change in the yield of chlorophyll a fluorescence is a common indicator of thermal stress in corals. The present study reports temporal variability in quantum yield measurements for 10 coral species in Ofu, American Samoa—a place known to experience elevated and variable seawater temperatures. In winter, the zooxanthellae generally had higher dark-adapted maximum quantum yield (Fv/Fm), higher ligh - Partners
Below are partners associated with this project.