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Pacific Coastal and Marine Science Center

USGS Coral Reef Project

Photo of coral reef.  

Tutuila, American Samoa

Satellite image of the island of Guam.

IKONOS satellite image of Tutuila

Overview

Tutuila encompasses 140 sq km (54 sq mi) 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 km (2,500 mi) 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 m (2,142 ft). The southern part of the island, however, is relatively flat. Tutuila boasts nearly 100 km (62 mi) 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 m (10 ft) 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.

Products

Divided by theme (Note: some products are listed multiple times as they cross multiple themes)

Circulation and sediment dynamics

Ferrario, F., Beck, M.W., Storlazzi, C.D., Micheli, F., Shepard, C.C., and Airoldi, L., 2014, The effectiveness of coral reefs for coastal hazard risk reduction and adaptation: Nature Communications, 5:3794, doi:10.1038/ncomms4794. [download PDF]

Rogers, J.S., Monismith, S.G., Feddersen, F., and Storlazzi, C.D., 2013, Hydrodynamics of spur and groove formations on a coral reef: Journal of Geophysical Research—Oceans, v. 118, p. 3,059-3,073, doi:10.1002/jgrc.20225.

Grady, A. E., Moore, L. J., Storlazzi, C. D., Elias, E., and Reidenbach, M. A., 2013, The influence of sea level rise and changes in fringing reef morphology on gradients in alongshore sediment transport: Geophysical Research Letters, v. 40, i. 12, p. 3096–3101, doi:10.1002/grl.50577.

Field, M.E., Chezar, H., and Storlazzi, C.D., 2012, SedPods—A low-cost coral proxy for measuring net sedimentation: Coral Reefs, v.32, p. 155–159, doi:10.1007/s00338-012-0953-5.

Stock, J.D., Cochran, S.A., Field, M.E, Jacobi, J.D., and Tribble, G., 2011, From ridge to reef—Linking erosion and changing watersheds to impacts on coral reef ecosystems in Hawaiʻi and the Pacific Ocean: U.S. Geological Survey Fact Sheet 2011–3049, 4 p.

Storlazzi, C.D., Elias, E., Field, M.E., and Presto, M.K., 2011, Numerical modeling of the impact of sea-level rise on fringing coral reef hydrodynamics and sediment transport: Coral Reefs, v. 30, Supplement 1, p. 83-96, doi:10.1007/s00338-011-0723-9.

Storlazzi, C.D., Field, M.E, and Bothner, M.H., 2011, The use (and misuse) of sediment traps in coral reef environments; Theory, observations, and suggested protocols: Coral Reefs, v. 30, no. 1, p. 23-38, doi:10.1007/s00338-010-0705-3.

U.S. Geological Survey, 2009, Science-based strategies for sustaining coral ecosystems: U.S. Geological Survey Fact Sheet 2009–3089, 4 p.

Climate change

Ferrario, F., Beck, M.W., Storlazzi, C.D., Micheli, F., Shepard, C.C., and Airoldi, L., 2014, The effectiveness of coral reefs for coastal hazard risk reduction and adaptation: Nature Communications, 5:3794, doi:10.1038/ncomms4794 [download PDF]

Grady, A. E., Moore, L. J., Storlazzi, C. D., Elias, E., and Reidenbach, M. A., 2013, The influence of sea level rise and changes in fringing reef morphology on gradients in alongshore sediment transport: Geophysical Research Letters, v. 40, i. 12, p. 3096–3101, doi:10.1002/grl.50577.

Field, M.E., Ogston, A.S., and Storlazzi, C.D., 2011, Rising sea level may cause decline of fringing coral reefs: Eos, v. 92, p. 273-280.

Storlazzi, C.D., Elias, E., Field, M.E., and Presto, M.K., 2011, Numerical modeling of the impact of sea-level rise on fringing coral reef hydrodynamics and sediment transport: Coral Reefs, v. 30, Supplement 1, p. 83-96, doi:10.1007/s00338-011-0723-9.

Piniak, G.A., and Brown, E.K., 2009, Temporal variability in chlorophyll fluorescence of back-reef corals in Ofu, American Samoa: Biological Bulletin, v. 216, p. 55-67.

U.S. Geological Survey, 2009, Science-based strategies for sustaining coral ecosystems: U.S. Geological Survey Fact Sheet 2009–3089, 4 p.

Jokiel, P.L., 2004, Temperature stress and coral bleaching, in Rosenberg, E., and Loya, Y., eds., Coral Health and Disease, Springer-Verlag, Heidelberg, p. 401–425.

Future reefs

Ferrario, F., Beck, M.W., Storlazzi, C.D., Micheli, F., Shepard, C.C., and Airoldi, L., 2014, The effectiveness of coral reefs for coastal hazard risk reduction and adaptation: Nature Communications, 5:3794, doi:10.1038/ncomms4794 [download PDF]

U.S. Geological Survey, 2009, Science-based strategies for sustaining coral ecosystems: U.S. Geological Survey Fact Sheet 2009–3089, 4 p.

Mapping

Cochran, S.A., Gibbs, A.E., D’Antonio, N.L., and Storlazzi, C.D., 2016, Benthic habitat map of U.S. Coral Reef Task Force Fagaʻalu Bay Priority Study Area, Tutuila, American Samoa: U.S. Geological Survey Open-File Report 20161077, 32 p., doi: 10.3133/ofr20161077.

D’Antonio, N.L., and Gibbs, A.E., 2016, Still-image frame grabs and benthic habitat interpretation of underwater video footage, March 2014, Fagaʻalu Bay, Tutuila Island, American Samoa: U.S. Geological Survey data release, doi: 10.5066/F7N877V1.

Gibbs, A.E., and D’Antonio, N.L., 2016, Underwater video footage, March 2014, Fagaʻalu Bay, Tutuila Island, American Samoa: U.S. Geological Survey data release, doi: 10.5066/F70V89V6.

U.S. Geological Survey, 2009, Science-based strategies for sustaining coral ecosystems: U.S. Geological Survey Fact Sheet 2009–3089, 4 p.

Other selected works

Coral Reefs Provide Critical Coastal Protection

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