Coral Reef Project: Molokaʻi Active
As part of the USGS Coral Reef Project, recent USGS work on Molokaʻi includes looking into the coral record to find clues to past sedimentation events.
Overview
The Friendly Isle of Molokaʻi encompasses 673 sq km (260 sq mi), making it the fifth largest of the main eight Hawaiian Islands. The north and west coasts of the island have little coral growth due to impact from northwest swell. However, protected from the southern swell waves by the islands of Lānaʻi and Kahoʻolowe, the south shore of Molokaʻi boasts the longest continuous fringing reef of the U.S. and its holdings. Studies by scientists at the University of Hawaiʻi's Coral Reef Assessment and Monitoring Program have shown that Molokaʻi has sites with the best coral coverage in the main eight Hawaiian Islands. Yet impacts from sediment run-off into the nearshore ecosystem have also caused areas of degradation of the south Molokaʻi reef.
Motivation
The USGS has used the south Molokaʻi reef as its test ground for developing benthic habitat mapping methods including remote sensing and underwater videography. Investigations into sedimentation along the south coast involve deployment of instrument packages to measure oceanographic conditions such as turbidity, currents, waves, temperature, and salinity. Recent work on Molokaʻi includes looking into the coral record to find clues to past sedimentation events.
The USGS has many cooperators on Molokaʻi including the U.S. Coral Reef Task Force (USCRTF) Hawaiian Local Action Strategy (HI-LAS) for Land-Based Pollution (LBP), University of Hawaiʻi, University of Washington, University of California, Santa Cruz, Australian National University, and The Nature Conservancy.
The Hawaiian island of Molokaʻi is just one of the USGS Coral Reef Project's study locations.
Below are data releases associated with this project.
Below are publications associated with this project.
Terrigenous sediment provenance from geochemical tracers, south Molokai reef flat, Hawaii
Coral Ba/Ca records of sediment input to the fringing reef of the southshore of Moloka'i, Hawai'i over the last several decades
Predictions of turbidity due to enhanced sediment resuspension resulting from sea-level rise on a fringing Coral Reef: Evidence from Molokai, Hawaii
Science-Based Strategies for Sustaining Coral Ecosystems
The coral reef of South Moloka'i, Hawai'i— Portrait of a sediment-threatened fringing reef
Coastal circulation and sediment dynamics in Hanalei Bay, Kaua'i. Part IV: Measurements of waves, currents, temperature, salinity, and turbidity: June-September 2006
Demise of reef-flat carbonate accumulation with late Holocene sea-level fall: Evidence from Molokai, Hawaii
Sand composition and transport history on a fringing coral reef, Molokai, Hawaii
Diurnal variability in turbidity and coral fluorescence on a fringing reef flat: Southern Molokai, Hawaii
Optimizing remote sensing and GIS tools for mapping and managing the distribution of an invasive mangrove (Rhizophora mangle) on South Molokai, Hawaii
Quantity, composition, and source of sediment collected in sediment traps along the fringing coral reef off Molokai, Hawaii
Temporal and spatial variability in the flow and dispersal of suspended-sediment on a fringing reef flat, Molokai, Hawaii
Below are news stories associated with this project.
Below are partners associated with this project.
- Overview
As part of the USGS Coral Reef Project, recent USGS work on Molokaʻi includes looking into the coral record to find clues to past sedimentation events.
Overview
The Friendly Isle of Molokaʻi encompasses 673 sq km (260 sq mi), making it the fifth largest of the main eight Hawaiian Islands. The north and west coasts of the island have little coral growth due to impact from northwest swell. However, protected from the southern swell waves by the islands of Lānaʻi and Kahoʻolowe, the south shore of Molokaʻi boasts the longest continuous fringing reef of the U.S. and its holdings. Studies by scientists at the University of Hawaiʻi's Coral Reef Assessment and Monitoring Program have shown that Molokaʻi has sites with the best coral coverage in the main eight Hawaiian Islands. Yet impacts from sediment run-off into the nearshore ecosystem have also caused areas of degradation of the south Molokaʻi reef.
Motivation
The USGS has used the south Molokaʻi reef as its test ground for developing benthic habitat mapping methods including remote sensing and underwater videography. Investigations into sedimentation along the south coast involve deployment of instrument packages to measure oceanographic conditions such as turbidity, currents, waves, temperature, and salinity. Recent work on Molokaʻi includes looking into the coral record to find clues to past sedimentation events.
The USGS has many cooperators on Molokaʻi including the U.S. Coral Reef Task Force (USCRTF) Hawaiian Local Action Strategy (HI-LAS) for Land-Based Pollution (LBP), University of Hawaiʻi, University of Washington, University of California, Santa Cruz, Australian National University, and The Nature Conservancy.
- Science
The Hawaiian island of Molokaʻi is just one of the USGS Coral Reef Project's study locations.
- Data
Below are data releases associated with this project.
- Publications
Below are publications associated with this project.
Filter Total Items: 38Terrigenous sediment provenance from geochemical tracers, south Molokai reef flat, Hawaii
Land-derived runoff is one of the greatest threats to coral-reef health. Identification of runoff sources is an important step in erosion mitigation efforts. A geochemical sediment provenance study was done in uplands and across the adjacent fringing reef on the southeast shore of Molokai, Hawaii, to determine whether sediment runoff originated from hillsides or gulches. Source-region identificatiAuthorsR.K. TakesueCoral Ba/Ca records of sediment input to the fringing reef of the southshore of Moloka'i, Hawai'i over the last several decades
The fringing reef of southern Moloka’i is perceived to be in decline because of land-based pollution. In the absence of historical records of sediment pollution, ratios of coral Ba/Ca were used to test the hypothesis that sedimentation has increased over time. Baseline Ba/Ca ratios co-vary with the abundance of red, terrigenous sediment visible in recent imagery. The highest values at One Ali’i arAuthorsN.G. Prouty, M.E. Field, J. D. Stock, S.D. Jupiter, M. McCullochPredictions of turbidity due to enhanced sediment resuspension resulting from sea-level rise on a fringing Coral Reef: Evidence from Molokai, Hawaii
Accelerating sea-level rise associated with global climate change will affect sedimentary processes on coral reefs and other shoreline environments by increasing energy and sediment resuspension. On reefs, sedimentation is known to increase coral stress and bleaching as particles that settle on coral surfaces interfere with photosynthesis and feeding, and turbidity induced by suspended sediment reAuthorsA.S. Ogston, M.E. FieldScience-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, scAuthorsThe coral reef of South Moloka'i, Hawai'i— Portrait of a sediment-threatened fringing reef
Moloka‘i, with the most extensive coral reef in the main Hawaiian Islands, is especially sacred to Hina, the Goddess of the Moon. As Hinaalo, she is the Mother of the Hawaiian people; as Hinapuku‘a, she is the Goddess of Fishermen; and in the form Hina‘opuhalako‘a, she is the Goddess who gave birth to coral, coral reefs, and all spiny marine organisms. Interdependence between the reef’s living resCoastal circulation and sediment dynamics in Hanalei Bay, Kaua'i. Part IV: Measurements of waves, currents, temperature, salinity, and turbidity: June-September 2006
High-resolution measurements of waves, currents, water levels, temperature, salinity and turbidity were made in Hanalei Bay, northern Kaua'i, Hawai'i, during the summer of 2006 to better understand coastal circulation, sediment dynamics, and the potential impact of a river flood in a coral reef-lined embayment during quiescent summer conditions. A series of bottommounted instrument packages were dAuthorsCurt D. Storlazzi, M. Katherine Presto, Joshua B. Logan, Michael E. FieldDemise of reef-flat carbonate accumulation with late Holocene sea-level fall: Evidence from Molokai, Hawaii
Twelve cores from the protected reef-flat of Molokai revealed that carbonate sediment accumulation, ranging from 3 mm year-1 to less than 1 mm year-1, ended on average 2,500 years ago. Modern sediment is present as a mobile surface veneer but is not trapped within the reef framework. This finding is consistent with the arrest of deposition at the end of the mid-Holocene highstand, known locally asAuthorsM.S. Engels, C. H. Fletcher, M. Field, C.L. Conger, C. BochicchioSand composition and transport history on a fringing coral reef, Molokai, Hawaii
Composition of sand grains from the beaches, reef flat, and fore reef of south Molokai, Hawaii, provides key information about the origin and transport history of sediment on the reef and adjacent beach. The most common grain types include coralline algae, coral, chemically altered carbonate, and siliciclastic grains. Minor components include calcareous algal plates (Halimeda), mollusk fragments,AuthorsR.S. Calhoun, M.E. FieldDiurnal variability in turbidity and coral fluorescence on a fringing reef flat: Southern Molokai, Hawaii
Terrigenous sediment in the nearshore environment can pose both acute and chronic stresses to coral reefs. The reef flat off southern Molokai, Hawaii, typically experiences daily turbidity events, in which trade winds and tides combine to resuspend terrigenous sediment and transport it alongshore. These chronic turbidity events could play a role in restricting coral distribution on the reef flat bAuthorsG.A. Piniak, C. D. StorlazziOptimizing remote sensing and GIS tools for mapping and managing the distribution of an invasive mangrove (Rhizophora mangle) on South Molokai, Hawaii
In 1902, the Florida red mangrove, Rhizophora mangle L., was introduced to the island of Molokai, Hawaii, and has since colonized nearly 25% of the south coast shoreline. By classifying three kinds of remote sensing imagery, we compared abilities to detect invasive mangrove distributions and to discriminate mangroves from surrounding terrestrial vegetation. Using three analytical techniques, we coAuthorsM. D'Iorio, S.D. Jupiter, S.A. Cochran, D.C. PottsQuantity, composition, and source of sediment collected in sediment traps along the fringing coral reef off Molokai, Hawaii
Sediment traps were used to evaluate the frequency, cause, and relative intensity of sediment mobility/resuspension along the fringing coral reef off southern Molokai (February 2000–May 2002). Two storms with high rainfall, floods, and exceptionally high waves resulted in sediment collection rates > 1000 times higher than during non-storm periods, primarily because of sediment resuspension by waveAuthorsMichael H. Bothner, R. L. Reynolds, M.A. Casso, C. D. Storlazzi, M.E. FieldTemporal and spatial variability in the flow and dispersal of suspended-sediment on a fringing reef flat, Molokai, Hawaii
A multi-year study was conducted on a shallow fringing reef flat on Molokai, Hawaii to determine the temporal and spatial dispersal patterns of terrigenous suspended sediment. During this study, trade-wind conditions existed for the majority of the year on the reef flat. The trade-wind conditions produced strong currents and resuspended moderate amounts of sediment on the reef flat on a daily basiAuthorsM.K. Presto, A.S. Ogston, C. D. Storlazzi, M.E. Field - News
Below are news stories associated with this project.
- Partners
Below are partners associated with this project.