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.
Demise of reef-flat carbonate accumulation with late Holocene sea-level fall: Evidence from Molokai, Hawaii
Submarine ground water discharge and fate along the coast of Kaloko-Honokohau National Historical Park, Hawaii Part I: Time-series measurements of currents, waves, salinity and temperature: November 2005 – July 2006
Science and management in the Hanalei watershed: A trans-disciplinary approach: Proceedings from the Hanalei watershed workshop, February 21-22, 2007
CO32- concentration and pCO2 thresholds for calcification and dissolution on the Molokai reef flat, Hawaii
- 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: 40Demise 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. BochicchioSubmarine ground water discharge and fate along the coast of Kaloko-Honokohau National Historical Park, Hawaii Part I: Time-series measurements of currents, waves, salinity and temperature: November 2005 – July 2006
The impending development for the west Hawai‘i coastline adjacent to Kaloko-Honokōhau National Historical Park (KAHO) may potentially alter coastal hydrology and water quality in the marine waters of the park. Water resources are perhaps the most significant natural and cultural resource component in the park, and are critical to the health and well being of six federally listed species. KAHO contAuthorsM. Katherine Presto, Curt D. Storlazzi, Joshua B. Logan, Eric E. GrossmanScience and management in the Hanalei watershed: A trans-disciplinary approach: Proceedings from the Hanalei watershed workshop, February 21-22, 2007
The results of recent studies in the Hanalei watershed are impressive, both in content and breadth. Funded, directed, and/or conducted by investigators from many disciplines from local organizations (the Hanalei Watershed Hui), the University of Hawai‘i, the State of Hawai‘i (Department of Health, Department of Land and Natural Resources), and Federal organizations (U.S. Department of Agriculture,AuthorsMichael E. Field, Carl J. Berg, Susan A. CochranCO32- concentration and pCO2 thresholds for calcification and dissolution on the Molokai reef flat, Hawaii
The severity of the impact of elevated atmospheric pCO2 to coral reef ecosystems depends, in part, on how sea-water pCO2 affects the balance between calcification and dissolution of carbonate sediments. Presently, there are insufficient published data that relate concentrations of pCO 2 and CO32- to in situ rates of reef calcification in natural settings to accurately predict the impact of elevateAuthorsK. K. Yates, R. B. Halley