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Investigating Coral Reef Ecosystems in Support of NASA’s Earth Science Program
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Coral Reef Health & Biodiversity Research

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Clues to Coral Reef Health and Biodiversity

Spectral Analysis and Remote Sensing of Coral Reefs

Coral reefs provide essential habitat for the world’s greatest marine biodiversity, as well as coastline protection, often providing first clues about marine ecosystem health because of the immediate response to environmental changes.  Unfortunately, these “canaries of the oceans” are in peril due to climate and human impacts.

In late 2005, coral reefs in the wider Caribbean suffered a widespread and the most severe bleaching event recorded to date that has resulted in extensive coral death in much of the region. Coral bleaching is associated with a variety of stresses including increased sea surface temperatures, which causes corals to expel the pigmented symbiotic microalgae living in their tissues, and thus appear bleached. Bleaching can lead to death of the corals that provide critical habitats and nursery grounds for marine fisheries, tourist attraction, and protection of coastlines from severe storms and wave action.

The NASA airborne mission imaged coral reefs of Puerto Rico and the US Virgin Islands in December 2005
The NASA airborne mission imaged coral reefs of Puerto Rico and the US Virgin Islands in December 2005 noted by orange arrows.

In mid-December 2005, in response to the coral bleaching event in the Caribbean, NASA Ames Research Center scientists teamed with scientists from NOAA’s Coral Reef Conservation and Biogeography Programs, the University of Puerto Rico at Mayaguez and the National Park Service (NPS) of the US Virgin Islands to investigate the status of coral bleaching in the Caribbean. This collaborative effort was in support of the US Coral Reef Task Force’s (USCRTF) resolution passed in November 2005 to mobilize Task Force agencies to assess the coral reef bleaching event, coral mortality, coral recovery, and the ecological impact of the September-October 2005 coral bleaching event in Puerto Rico (PR) and the US Virgin Islands (USVI).

2005 DCS image of Buck Island, St. Croix, U.S. Virgin Islands.
2005 DCS image of Buck Island, St. Croix, U.S. Virgin Islands.

This assessment consisted of collection of hyperspectral data using the NASA Airborne Visible Infrared Imaging Spectrometer (AVIRIS) by NASA Jet Propulsion Laboratory scientists and the NASA Ames high resolution Digital Camera System (DCS) supported by UC Santa Cruz Airborne Sensor Facility scientists with field data collection by NASA Ames researchers in collaboration primarily with researchers from the University of Puerto Rico, NOAA’s Biogeography Program, and the USVI National Park Service (NPS).

Handheld spectroradiometers measure reflected light readings from coral. Researchers using handheld spectroradiometers measure reflected light readings from coral.

Sensors were used to document the extent of the bleaching, gather biological and optical data on healthy, bleached, and recovering corals, and measure oceanographic properties to understand the dynamics of the bleaching event. Aircraft-based sensors provide high spectral and spatial resolution data that enhance our understanding of satellite data. For this study, visible spectrum AVIRIS light data reflecting off of the coral reef and surrounding reef bottom will be used to quantify bleaching extent and coral health.

Field measurements taken in Puerto Rico and USVI will validate and complement the airborne data. Coupled remotely sensed and in situ data will allow researchers to better understand the ecology of this region impacted by environmental events, and improve modeling of future bleaching events.

Also, this project’s previous AVIRIS missions over the Florida Keys and Puerto Rico in August 2004 and Kaneohe Bay, Hawaii in March 2005 will provide additional airborne hyperspectral imagery for quantifying coral reef biological and optical properties.

 

 

Factoids

Our Previous Coral Reef Research

 

Comparison of healthy and diseased coral.

Comparison of healthy and diseased coral.

 

 

 

Bleached elkhorn coral, Puerto Rico, 2005.

Bleached elkhorn coral, Puerto Rico, 2005.

 

 

 

Acropora palmata, or elkhorn coral with white band disease, Bahamas, 2002.

Acropora palmata, or elkhorn coral with white band disease, Bahamas, 2002.

 

 

 

View our Photo Gallery

 

Our Previous Coral Reef Research

Research funded by NASA’s Ocean Biology and Biogeochemistry Program
and NASA’s Interdisciplinary Research in Earth Science Program