Reef Hydrodynamics and Sediment Processes
Science Center Objects
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.
Tripod deployed on the reef flat off Jurabi, Ningaloo World Heritage Site, Western Australia, with instrumentation designed to measure tides, waves, currents, and sediment being transported across the reef. Photo credit: Curt Storlazzi, USGS
The Problem
Over the past decade, we have primarily focused on fine-grained terrestrial sediment dynamics on reefs, due to its role as the greatest stressor to high-island fringing reefs throughout the U.S. and U.S.-Affiliated Pacific Islands, such as Hawaii, Guam, American Samoa, and large Office of Insular Affairs islands. However, recently we have expanded our focus to include carbonate sediment, as approximately 80-90% of coral reefs are constructed of lithified carbonate sediment (carbonate sand and rubble adhered together by calcareous algae, not intact coral growth). Because this carbonate sediment is a critical component of beach sediment supply, it represents an important resource for recreation and coastal storm protection. Although a key factor in the vertical growth of reefs and their ability to keep up with rising sea levels, carbonate reef sediment dynamics are poorly understood and this knowledge gap was recently determined to be a critical area of research for investigating climate-change impacts to coral reef-lined coasts.
Numerically simulated Lagrangian coral larval dispersal patterns from the Olowalu reef on west Maui, Hawaiʻi, for four different coral larval spawning events. Such modeling demonstrates the potential for a given reef to seed different islands and their respective reefs over relatively short timescales.
Our Approach
The overall objective of this research is to better understand how hydrodynamics and sediment processes influence the development of coral reefs and their adjacent shorelines. Specifically, we are:
- Evaluating the role of coral-reef morphology on waves and wave-driven water levels over coral reefs and their resulting influence on coastal flooding.
- Elucidating the patterns of flow over coral reefs that result from different forcing mechanisms such as waves, currents, surface tides, internal tides, and subtidal motions.
- Determining the sources, pathways, and retention times of sediment, nutrients, and contaminants over complex coral reef morphologies.
- Identifying the circulation pathways that link separate reefs through larval or pollutant transport, and determine the spatial and temporal scales at which these pathways occur.
- Evaluating how these processes and linkages will be affected by projected changes in climate such as sea-level rise and changes in the frequency and intensity of storms.
The overall objective of this research effort is to better understand how circulation and sediment processes impact coral reefs and their adjacent coastlines.
Caption for large photo at top of page: Photograph of large (6-meter-/20-foot-high) waves resuspending terrestrial flood sediment on the coral reefs off Puʻukoholā Heiau National Historic Site and Kawaihae Harbor, Hawaiʻi.
Coral Reef Project
Explore the fascinating undersea world of coral reefs. Learn how we map, monitor, and model coral reefs so we can better understand, protect, and preserve our Nation's reefs.
Spectral wave-driven bedload transport across a coral reef flat/lagoon complex
Coral reefs are an important source of sediment for reef-lined coasts by helping to maintain beaches while also providing protection in the form of wave energy dissipation. Understanding the mechanisms by which sediment is delivered to the coast as well as better constraining the total volumes generated are critical for projecting future coastal...
Rosenberger, Kurt J.; Storlazzi, Curt D.; Cheriton, Olivia; Pomeroy, Andrew; Hansen, Jeff E.; Lowe, Ryan; Buckley, Mark Pulse sediment event does not impact the metabolism of a mixed coral reef community
Sedimentation can bury corals, cause physical abrasion, and alter both spectral intensity and quality; however, few studies have quantified the effects of sedimentation on coral reef metabolism in the context of episodic sedimentation events. Here, we present the first study to measure coral community metabolism - calcification and photosynthesis...
Keisha Bahr; Ku'ulei Rodgers; Paul Jokiel; Prouty, Nancy G.; Storlazzi, Curt D. Integrating structure from motion, numerical modelling and field measurements to understand carbonate sediment transport in coral reef canopies
Reef canopies are complex and extremely variable across a range of spatial scales. This variability affects the velocity above as well as within the canopy, and directly impacts the transport of sediment along the bed as well as suspended in the water column. How a canopy affects the transport of sediment is important to understand and predict...
Pomeroy, Andrew; Storlazzi, Curt D.; Rosenberger, Kurt J.; Hatcher, Gerry; Warrick, Jonathan The influence of sea level on incident and infragravity wave-driven sediment dynamics across a fringing coral reef
Coral reefs generate significant volumes of carbonate sediment that becomes the primary source of beach material along many low-latitude shorelines that protect hundreds of millions of people globally. Despite this fact, there is little understanding of the specific processes that transport the carbonate sediment produced on the outer portions of...
Storlazzi, Curt D.; Cheriton, Olivia; Rosenberger, Kurt J.; Pomeroy, Andrew; Lowe, Ryan J. Controls on sediment transport over coral reefs off southwest Puerto Rico: Seasonal patterns and Hurricane Maria
Guánica Bay in southwest Puerto Rico is highly turbid and has some of the highest PCB concentrations in the USA. To investigate how and to what extent the bay waters influence coral reef ecosystem health along the coastline, 6 months of hydrodynamic data were collected at 8 sites on the insular shelf. Bed shear stresses were primarily driven by...
Cheriton, Olivia; Storlazzi, Curt D.; Rosenberger, Kurt J.; Sherman, Clark Assessing morphologic controls on atoll island alongshore sediment transport gradients due to future sea-level rise
Atoll islands’ alongshore sediment transport gradients depend on how island and reef morphology affect incident wave energy. It is unclear, though, how potential atoll morphologic configurations influence shoreline erosion and/or accretion patterns, and how these relationships will respond to future sea-level rise (SLR). Schematic atoll models...
Shope, James B.; Storlazzi, Curt D. Spatial and temporal variability in ripple formation and migration across a coral reef flat and lagoon
Sediment produced on fringing coral reefs that is transported along the bed or in suspension affects ecological reef communities as well as the morphological development of the reef, lagoon, and adjacent shoreline. This study quantified the physical process contribution and relative importance of sea‐swell waves, infragravity waves, and mean...
Rosenberger, Kurt J.; Storlazzi, Curt D.; Pomeroy, Andrew; Cheriton, Olivia; Lowe, Ryan J.; Hansen, Jeff Geochemical sourcing of runoff from a young volcanic watershed to an impacted coral reef in Pelekane Bay, Hawaii
Runoff of sediment and other contaminants from developed watersheds threatens coastal ecosystems and services. A sediment geochemical sourcing study was undertaken on a sediment-impacted coral reef flat to identify terrestrial sediment sources and how these changed over time. Geochemical signatures were identified for watershed...
Takesue, Renee K.; Storlazzi, Curt D. Meteorologic, 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...
Storlazzi, Curt D.; Cheriton, Olivia M.; Messina, A. M.; Biggs, Trent W. Spatial variability of sediment transport processes over intra‐ and subtidal timescales within a fringing coral reef system
Sediment produced on fringing coral reefs that is transported along the bed or in suspension affects ecological reef communities as well as the morphological development of the reef, lagoon, and adjacent shoreline. This study quantified the physical process contribution and relative importance of incident waves, infragravity waves, and mean...
Pomeroy, Andrew; Lowe, Ryan J.; Ghisalberti, Marco; Winter, Gundula; Storlazzi, Curt D.; Cuttler, Michael V. W. Mechanisms of wave‐driven water level variability on reef‐fringed coastlines
Wave‐driven water level variability (and runup at the shoreline) is a significant cause of coastal flooding induced by storms. Wave runup is challenging to predict, particularly along tropical coral reef‐fringed coastlines due to the steep bathymetric profiles and large bottom roughness generated by reef organisms, which can violate assumptions in...
Buckley, Mark L.; Lowe, Ryan J.; Hansen, Jeff E.; van Dongeren, Ap R.; Storlazzi, Curt D. Projected atoll shoreline and run-up changes in response to sea-level rise and varying large wave conditions at Wake and Midway Atolls, Northwestern Hawaiian Islands
Atoll islands are dynamic features that respond to seasonal alterations in wave conditions and sea level. It is unclear how shoreline wave run-up and erosion patterns along these low elevation islands will respond to projected sea-level rise (SLR) and changes in wave climate over the next century, hindering communities' preparation for the future...
Shope, James B.; Storlazzi, Curt D.; Hoeke, Ron