Sea-Level Rise and Climate Change Impacts to Reefs Completed
Learn how the USGS studies sea-level rise and climate change impacts to coral reefs.
This study is part of the USGS Coral Reef Project.
The Problem
There is a growing body of evidence indicating that the rate of sea-level rise has increased relative to the past century and will continue to increase in the 21st century; that evidence has recently been summarized by the Intergovernmental Panel on Climate Change (IPCC). If all aspects of reef morphology—colony size and shape, cross-reef relief, surface rugosity, and so on—keep pace with the rising sea levels, then it is likely that changes in depth-controlled physical processes will be minimal to non-detectible. However, based on rates of vertical reef accretion in Hawaiʻi and throughout the Pacific (which are an order of magnitude smaller than predicted rates of sea-level rise), it is unlikely that reefs there and other locations will keep pace, and their inability to do so will lead to subtle but important changes in selected physical processes on some coral reefs.
In addition, recent studies indicate the flux of submarine groundwater discharge from land to coral reefs in Hawaiʻi and other high islands is substantial, and often significantly colder and enriched in terrestrial-derived nutrients than surrounding seawater. Ecosystem functions of submarine groundwater discharge to coral reef ecosystems are not quantified but can be hypothesized to (1) buffer thermal stress (bleaching) in corals experiencing warming, and (2) supply nutrients to otherwise oligotrophic coastal waters. While an excess of the latter has been observed to cause complete phase shifts in the form of wholesale loss of coral and replacement by macroalgae, the role of the former has not been tested. Both may be significantly altered by impending climate change and proposed land use that alter groundwater quantity, quality, flux, composition, and fate, especially in rapidly developing areas. This effort is focused on submarine groundwater discharge, its role in shaping coral reef ecosystem structure, and the ecosystem services it provides.
The Approach
The overall objective of this research effort is to better understand how climate change may impact coral reefs. Achievement of this objective requires an understanding of the physical parameters driving change in coral reefs and the resulting ecosystem processes. The goals of this effort are to:
- How will reefs respond to rapid sea-level rise at a decadal time-scale?
- How will increased wave energy and altered circulation across reefs affect circulation and sediment, nutrient, contaminant, and larval dynamics?
- Do thresholds exist in the rate of sea-level rise that would push a reef ecosystem from a state of stability to one of net loss?
- How may changes in precipitation, recharge, and human-induced withdraws impact submarine groundwater discharge to the coastal zone?
- How will coral reefs respond to variations in submarine groundwater discharge predicted to occur due to climate change?
The approach to these interdisciplinary studies will rely on a combination of field measurements and physics-based numerical monitoring. We use a wide range of tools to try to answer these questions, including: oceanographic instruments (for example, acoustic Doppler current profilers, wave/tide gauges, temperature sensors, salinity sensors, chemical sensors) mounted on the seabed or on moorings, water-column profilers with similar suites of sensors, coral cores, geophysical water-column and sub-bottom surveys, and physics-based numerical models.
Below are data releases associated with this project.
Below are publications associated with this study.
Rapid fluctuations in flow and water-column properties in Asan Bay, Guam: implications for selective resilience of coral reefs in warming seas
Forecasting the impact of storm waves and sea-level rise on Midway Atoll and Laysan Island within the Papahānaumokuākea Marine National Monument—a comparison of passive versus dynamic inundation models
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
Growth rate and age distribution of deep-sea black corals in the Gulf of Mexico
Submarine groundwater discharge and fate along the coast of Kaloko-Honokohau National Historical Park, Island of Hawai`i: Part 3, spatial and temporal patterns in nearshore waters and coastal groundwater plumes, December 2003-April 2006
Predictions of turbidity due to enhanced sediment resuspension resulting from sea-level rise on a fringing Coral Reef: Evidence from Molokai, Hawaii
Coral proxy record of decadal-scale reduction in base flow from Moloka'i, Hawaii
Science-Based Strategies for Sustaining Coral Ecosystems
Temporal variability in chlorophyll fluorescence of back-reef corals in Ofu, American Samoa
Submarine ground-water discharge and fate along the coast of Kaloko-Honokohau National Historical Park, Island of Hawai'i: Part 2, spatial and temporal variations in salinity, radium-isotope activity, and nutrient concentrations in coastal waters, Decembe
Submarine groundwater discharge and nutrient addition to the coastal zone and coral reefs of leeward Hawai'i
- Overview
Learn how the USGS studies sea-level rise and climate change impacts to coral reefs.
This study is part of the USGS Coral Reef Project.
The Problem
There is a growing body of evidence indicating that the rate of sea-level rise has increased relative to the past century and will continue to increase in the 21st century; that evidence has recently been summarized by the Intergovernmental Panel on Climate Change (IPCC). If all aspects of reef morphology—colony size and shape, cross-reef relief, surface rugosity, and so on—keep pace with the rising sea levels, then it is likely that changes in depth-controlled physical processes will be minimal to non-detectible. However, based on rates of vertical reef accretion in Hawaiʻi and throughout the Pacific (which are an order of magnitude smaller than predicted rates of sea-level rise), it is unlikely that reefs there and other locations will keep pace, and their inability to do so will lead to subtle but important changes in selected physical processes on some coral reefs.
In addition, recent studies indicate the flux of submarine groundwater discharge from land to coral reefs in Hawaiʻi and other high islands is substantial, and often significantly colder and enriched in terrestrial-derived nutrients than surrounding seawater. Ecosystem functions of submarine groundwater discharge to coral reef ecosystems are not quantified but can be hypothesized to (1) buffer thermal stress (bleaching) in corals experiencing warming, and (2) supply nutrients to otherwise oligotrophic coastal waters. While an excess of the latter has been observed to cause complete phase shifts in the form of wholesale loss of coral and replacement by macroalgae, the role of the former has not been tested. Both may be significantly altered by impending climate change and proposed land use that alter groundwater quantity, quality, flux, composition, and fate, especially in rapidly developing areas. This effort is focused on submarine groundwater discharge, its role in shaping coral reef ecosystem structure, and the ecosystem services it provides.
The Approach
The overall objective of this research effort is to better understand how climate change may impact coral reefs. Achievement of this objective requires an understanding of the physical parameters driving change in coral reefs and the resulting ecosystem processes. The goals of this effort are to:
- How will reefs respond to rapid sea-level rise at a decadal time-scale?
- How will increased wave energy and altered circulation across reefs affect circulation and sediment, nutrient, contaminant, and larval dynamics?
- Do thresholds exist in the rate of sea-level rise that would push a reef ecosystem from a state of stability to one of net loss?
- How may changes in precipitation, recharge, and human-induced withdraws impact submarine groundwater discharge to the coastal zone?
- How will coral reefs respond to variations in submarine groundwater discharge predicted to occur due to climate change?
The approach to these interdisciplinary studies will rely on a combination of field measurements and physics-based numerical monitoring. We use a wide range of tools to try to answer these questions, including: oceanographic instruments (for example, acoustic Doppler current profilers, wave/tide gauges, temperature sensors, salinity sensors, chemical sensors) mounted on the seabed or on moorings, water-column profilers with similar suites of sensors, coral cores, geophysical water-column and sub-bottom surveys, and physics-based numerical models.
- Data
Below are data releases associated with this project.
- Publications
Below are publications associated with this study.
Filter Total Items: 40Rapid fluctuations in flow and water-column properties in Asan Bay, Guam: implications for selective resilience of coral reefs in warming seas
Hydrodynamics and water-column properties were investigated off west-central Guam from July 2007 through January 2008. Rapid fluctuations, on time scales of 10s of min, in currents, temperature, salinity, and acoustic backscatter were observed to occur on sub-diurnal frequencies along more than 2 km of the fore reef but not at the reef crest. During periods characterized by higher sea-surface tempAuthorsCurt D. Storlazzi, Michael E. Field, Olivia M. Cheriton, M.K. Presto, J.B. LoganForecasting the impact of storm waves and sea-level rise on Midway Atoll and Laysan Island within the Papahānaumokuākea Marine National Monument—a comparison of passive versus dynamic inundation models
Two inundation events in 2011 underscored the potential for elevated water levels to damage infrastructure and affect terrestrial ecosystems on the low-lying Northwestern Hawaiian Islands in the Papahānaumokuākea Marine National Monument. The goal of this study was to compare passive "bathtub" inundation models based on geographic information systems (GIS) to those that include dynamic water levelAuthorsCurt D. Storlazzi, Paul Berkowitz, Michelle H. Reynolds, Joshua B. LoganRising 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 surfaceAuthorsMichael E. Field, Andrea S. Ogston, Curt D. StorlazziNumerical 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 orderAuthorsC. D. Storlazzi, E. Elias, M.E. Field, M.K. PrestoGrowth rate and age distribution of deep-sea black corals in the Gulf of Mexico
Black corals (order Antipatharia) are important long-lived, habitat-forming, sessile, benthic suspension feeders that are found in all oceans and are usually found in water depths greater than 30 m. Deep-water black corals are some of the slowest-growing, longest-lived deep-sea corals known. Previous age dating of a limited number of black coral samples in the Gulf of Mexico focused on extrapolateAuthorsN.G. Prouty, E.B. Roark, N.A. Buster, Steve W. RossSubmarine groundwater discharge and fate along the coast of Kaloko-Honokohau National Historical Park, Island of Hawai`i: Part 3, spatial and temporal patterns in nearshore waters and coastal groundwater plumes, December 2003-April 2006
During seven surveys between December 2003 and April 2006, 1,045 depth profiles of surface water temperature and salinity were collected to examine variability in water column properties and the influence of submarine groundwater discharge (SGD) on the nearshore waters and coral reef complex of Kaloko-Honokōhau National Historical Park, Island of Hawai‘i. This effort was made to characterize the vAuthorsEric E. Grossman, Joshua B. Logan, M. Katherine Presto, Curt D. StorlazziPredictions 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. FieldCoral proxy record of decadal-scale reduction in base flow from Moloka'i, Hawaii
Groundwater is a major resource in Hawaii and is the principal source of water for municipal, agricultural, and industrial use. With a growing population, a long-term downward trend in rainfall, and the need for proper groundwater management, a better understanding of the hydroclimatological system is essential. Proxy records from corals can supplement long-term observational networks, offering anAuthorsNancy G. Prouty, Stacy D. Jupiter, Michael E. Field, Malcolm T. McCullochScience-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, scAuthorsTemporal 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 lighAuthorsG.A. Piniak, E.K. BrownSubmarine ground-water discharge and fate along the coast of Kaloko-Honokohau National Historical Park, Island of Hawai'i: Part 2, spatial and temporal variations in salinity, radium-isotope activity, and nutrient concentrations in coastal waters, Decembe
The aquatic resources of Kaloko-Honokohau National Historical Park, including rocky shoreline, fishponds, and anchialine pools, provide habitat to numerous plant and animal species and offer recreational opportunities to local residents and tourists. A considerable amount of submarine groundwater discharge was known to occur in the park, and this discharge was suspected to influence the park's watAuthorsKaren Knee, Joseph Street, Eric E. Grossman, Adina PaytanSubmarine groundwater discharge and nutrient addition to the coastal zone and coral reefs of leeward Hawai'i
Multiple tracers of groundwater input (salinity, Si, 223Ra, 224Ra, and 226Ra) were used together to determine the magnitude, character (meteoric versus seawater), and nutrient contribution associated with submarine groundwater discharge across the leeward shores of the Hawai'ian Islands Maui, Moloka'i, and Hawai'i. Tracer abundances were elevated in the unconfined coastal aquifer and the nearshoreAuthorsJ.H. Street, K.L. Knee, E. E. Grossman, A. Paytan