Why are coral reefs in peril and what is being done to protect them?
Coral reefs can be damaged by natural processes, such as storms, but they are increasingly at risk from human activities. Oil spills and pollutants can threaten entire reefs. Excessive nutrients from land sources, such as sewage and agricultural fertilizers, promote the growth of algae that can smother corals. Other organisms harmful to corals, such as crown-of-thorns starfish, multiply when the species that prey on them are removed.
Coral productivity is also decreased when land developments for agriculture, industry, and housing increase sediment transported from land into coastal waters as runoff. This clouds the waters and blocks light necessary for photosynthesis by algae living in corals. Corals face serious risks from various diseases. When corals are stressed, they often expel the algal symbionts that are critical to their health in a process commonly known as coral bleaching. One known cause of coral bleaching is increases in ocean temperatures, possibly due to global warming.
Scientists worldwide are working to understand the impacts of natural processes and human activities on the health and sustainability of coral reefs. The USGS is contributing to the effort to understand the biological and geological controls that affect our Nation's coral reefs. USGS coral reef research focuses on detailed mapping of reefs, the development of monitoring techniques, studying reefs' geologic growth and development, and how they are affected by water quality, fishing, and sedimentary and hydrologic processes. These efforts will help provide information that is essential if coral reefs are to be saved.
Learn more:
Related Content
What is marine geology?
What are the long-term effects of climate change?
What is the difference between global warming and climate change?
How would sea level change if all glaciers melted?
What are the differences between endangered, threatened, imperiled, and at-risk species?
Why do animals and plants become endangered?
The major coral reefs of Maui Nui, Hawai‘i—distribution, physical characteristics, oceanographic controls, and environmental threats
Coral reefs are widely recognized as critical to Hawaiʻi’s economy, food resources, and protection from damaging storm waves. Yet overfishing, land-based pollution, and climate change are threatening the health and sustainability of those reefs, and accordingly, both the Federal and State governments have called for protection and effective...
Field, Michael E.; Storlazzi, Curt D.; Gibbs, Ann E.; D'Antonio, Nicole L.; Cochran, Susan A.
USGS research on Atlantic coral reef ecosystems
Overview Coral reefs are massive, biomineralized structures that protect coastal communities by acting as barriers to hazards such as hurricanes and tsunamis. They provide sand for beaches through the natural process of erosion, support tourism and recreational industries, and provide essential habitat for fisheries. The continuing global...
Kuffner, Ilsa B.; Yates, Kimberly K.; Zawada, David G.; Richey, Julie N.; Kellogg, Christina A.; Toth, Lauren T.
From ridge to reef—linking erosion and changing watersheds to impacts on the coral reef ecosystems of Hawai‘i and the Pacific Ocean
Coral reef ecosystems are threatened by unprecedented watershed changes in the United States and worldwide. These ecosystems sustain fishing and tourism industries essential to the economic survival of many communities. Sediment, nutrients, and pollutants from watersheds are increasingly transported to coastal waters, where these contaminants...
Stock, Jonathan D.; Cochran, Susan A.; Field, Michael E.; Jacobi, James D.; Tribble, Gordon
Coral calcification in a changing ocean
Animals and plants that live in the ocean form skeletons and other hard parts by combining calcium ions and carbonate ions to create calcium carbonate. This process is called calcification. In tropical and subtropical oceans, the calcification of corals and other organisms creates reefs that protect islands, produce beautiful white-sand beaches,...
Kuffner, Ilsa B.
Effects of ocean acidification and sea-level rise on coral reefs
U.S. Geological Survey (USGS) scientists are developing comprehensive records of historical and modern coral reef growth and calcification rates relative to changing seawater chemistry resulting from increasing atmospheric CO2 from the pre-industrial period to the present. These records will provide the scientific foundation for predicting future...
Yates, K.K.; Moyer, R.P.
Strategic Science for Coral Ecosystems 2007-2011
Shallow and deep coral ecosystems are being imperiled by a combination of stressors. Climate change, unsustainable fishing practices, and disease are transforming coral communities at regional to global scales. At local levels, excessive amounts of sediments, nutrients, and contaminants are also impacting the many benefits that healthy coral...
Applying New Methods to Diagnose Coral Diseases
Coral disease, one of the major causes of reef degradation and coral death, has been increasing worldwide since the 1970s, particularly in the Caribbean. Despite increased scientific study, simple questions about the extent of disease outbreaks and the causative agents remain unanswered. A component of the U.S. Geological Survey Coral Reef...
Kellogg, Christina A.; Zawada, David G.
Science-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...
Disease of coral and coral reef fishes
The Department of the Interior protects sensitive habitats amounting to about 3,600,000 acres of coral reefs and other submerged lands. These reefs are important ecosystems in 13 National Wildlife Refuges, 10 National Parks and in certain territorial waters such as the Wake Atoll.
Panek, Frank
The 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...
Field, Michael E.; Cochran, Susan A.; Logan, Joshua B.; Storlazzi, Curt D.
Coral Reef Barriers Provide Flood Protection for More Than 18,000 People and $1.8 Billion Worth of Coastal Infrastructure and Economic Activity Annually
Today, the U.S. Geological Survey (USGS) released the findings of a new, in-depth study titled “Rigorously Valuing the Role of U.S. Coral Reefs in Coastal Hazard Risk Reduction,” – funded in part by the U.S. Department of the Interior’s (DOI) Office of Insular Affairs –
Florida's Coral Reefs Provide Window into the Past
USGS study finds most have grown little in 3000 years
New Control Methods Can Help Protect Coral Reefs from Invasive Species
Honolulu, Hawaii – Control efforts such as the removal of shipwrecks and application of chlorine may help mitigate the damaging effects of corallimorph, which is a type of invasive anemone, on valuable coral reefs in the Central Pacific Ocean, according to a new U.S. Geological Survey study.
Florida Corals Tell of Cold Spells and Dust Bowls Past, Foretell Weather to Come
Boulder corals in the waters of Dry Tortugas National Park, 70 miles from Key West, contain evidence that confirms a centuries-old sea temperature cycle linked to rains, droughts and hurricanes.
Many Atolls May be Uninhabitable Within Decades Due to Climate Change
SANTA CRUZ, Calif. — A new study shows that the combined effect of storm-induced wave-driven flooding and sea level rise on island atolls may be more severe and happen sooner than previous estimates of inundation predicted by passive “bathtub” modeling for low-lying atoll islands, and especially at higher sea levels forecasted for the future due to climate change.
Climate Change Reduces Coral Reefs’ Ability to Protect Coasts
SANTA CRUZ, Calif. — Coral reefs, under pressure from climate change and direct human activity, may have a reduced ability to protect tropical islands against wave attack, erosion and salinization of drinking water resources, which help to sustain life on those islands.
Ocean Warming Affecting Florida Reefs
Late-summer water temperatures near the Florida Keys were warmer by nearly 2 degrees Fahrenheit in the last several decades compared to a century earlier, according to a new study by the U.S. Geological Survey.
Coral Reefs are Critical for Risk Reduction & Adaptation
Stronger storms, rising seas, and flooding are placing hundreds of millions people at risk around the world, and big part of the solution to decrease those risks is just off shore. A new study finds that coral reefs reduce the wave energy that would otherwise impact coastlines by 97 percent.
New Approach to Measuring Coral Growth Offers Valuable Tool for Reef Managers
A new more sensitive weight-based approach for monitoring coral growth in the wild has been developed by U.S. Geological Survey researchers leading to more definitive answers about the status of coral reefs.
2,000 Year-old Deep-sea Black Corals call Gulf of Mexico Home
For the first time, scientists have been able to validate the age of deep-sea black corals in the Gulf of Mexico. They found the Gulf is home to 2,000 year-old deep-sea black corals, many of which are only a few feet tall.
Reversing Coral Reef Decline in Hawai`i — A New Look at a Critical Problem
New discoveries about how even small amounts of sediment can severely impact fragile ocean coral and suggestions about solutions are illustrated and described in a new book written by a team of U.S. Geological Survey (USGS) scientists and their colleagues. Coral reefs are in decline worldwide, and a leading cause is the runoff of sediment and pollutants from nearby land surfaces.
Coral Reef Builders Vulnerable to Ocean Acidification
As pH declines in the world's oceans, the effects on coral reefs could be more harmful than previously thought. This pH decline, a process known as "ocean acidification," occurs due to absorption of carbon dioxide from the atmosphere. As a result, the growth of reef builders may be severely inhibited.
Why are coral reefs in peril and what is being done to protect them?
A short video on information related to coral reefs and the USGS.
PubTalk 4/2018 - Coral Reefs
Title: The Role of U.S. Coral Reefs in Coastal Protection - Rigorously valuing flood reduction benefits to inform coastal zone management decisions
- Coral reefs are a first line of coastal defense
- We can account for the physical defense that reefs provide
- We can provide value-based information to guide restoration efforts at management-relevant
Coral Bleaching and Disease: Effects on Threatened Corals and Reefs
Coral Bleaching and Disease: Effects on Threatened Corals and Reefs: White plague disease caused major coral mortality following bleaching in 2005.
USGS research diver over coral reef in the Dry Tortugas
USGS research diver over coral reef in the Dry Tortugas
SCUBA Diver Collects Corals for Paleoclimate
A USGS SCUBA Diver Collects a Core from a Coral Using a Hydraulic Drilling System in the U.S. Virgin Islands. USGS Image (I. Kuffner).
PubTalk 9/2015 — Coral Reefs, Climate Change, and Atoll Sustainability
Will Micronesians become the U.S.'s first climate change refugees?
by Curt Storlazzi, USGS Research Geologist and Oceanographer
- Sea level is rising, threatening low-lying atoll islands throughout the western Pacific Ocean
- Climate change is degrading the coral reefs that atoll islands have developed upon, decreasing
Resilience Potential of Coral Reefs in the Mariana Islands
This webinar was conducted as part of the "Climate Change Science and Management Webinar Series" held in partnership between the USGS National Climate Change and Wildlife Science Center and the FWS National Conservation Training Center. Webinar Summary: Reducing coral reef vulnerability to climate change requires that managers understand and support the natural resilience
...
Exploring Causes of Coral Disease
The Hawaiian Islands’ beautiful ocean and beaches attract more than 8.5 million tourists each year. The USGS aims to help Hawaii preserve its underwater natural resources by tracing how oceanography may influence coral disease outbreaks. Looking into contaminants in the freshwater, or how quickly a bay may or may not flush, will help enrich future and past studies about
...
Fire Coral Bleaching
Colonies of “blade fire coral” that have lost their symbiotic algae, or “bleached,” on a reef off of Islamorada, Florida. Hard and soft corals are presently bleaching- losing their symbiotic algae – all over the coral reefs of the Florida Keys due to unusually warm ocean temperatures this summer. Months with waters warmer than 85 F have become more frequent in
...
PubTalk 6/2014 — Into the Abyss
Living Without Light
by Nancy Prouty, Research Oceanographer
- As archives of natural and human activities, deep-sea corals are windows to the past.
- Scientific studies of these slow-growing and long-living animals lead to good stewardship for healthy ecosystems.
- Deep-sea coral communities are
Sampling Diseased Coral
USGS scientist Thierry Work takes a sample from diseased coral at Tunnels Reef on the north shore of Kauai, Hawaii
A Healthy Coral Reef
Taken at Palmyra National Wildlife Refuge