NASA's CORAL Mission Takes Reef Studies To New Level

NASA plans to take a new and improved approach to studying coral reefs this year, with the launch of a three-year field expedition conducted with advanced instruments to survey the world's reefs in far greater detail than ever before.

Researchers from the COral Reef Airborne Laboratory (CORAL) will take aerial and up-close, underwater measurements to better assess the condition of these threatened ecosystems. Their findings will be used to create a unique database of uniform scale and quality, according to a news release.

"Right now, the state of the art for collecting coral reef data is scuba diving with a tape measure," Eric Hochberg, CORAL principal investigator and scientist at the Bermuda Institute of Ocean Sciences, St. George's, explained in the release. "It's analogous to looking at a few trees and then trying to say what the forest is doing."

Coral reefs are valuable marine ecosystems, home to a quarter of all ocean fish species. Yet they are in trouble and very little of the world's reef area has actually been studied scientifically. In fact, most research stems from minimal dive expeditions, in which reefs were measured at only a few sites.

That's where NASA's new method comes into play.

Alternatively, the CORAL expedition will survey the condition of entire reef systems in Florida, Hawaii, Palau, the Mariana Islands and Australia, using an airborne instrument called the Portable Remote Imaging Spectrometer (PRISM). Scientists will also carry out concurrent in-water measurements to validate the airborne measurements.

Hochberg and his team will be analyzing the reef conditions in the context of the prevailing environment, including physical, chemical, and human factors in an attempt find out how the environment ultimately shapes reef ecosystems.

"We've seen the reefs of Jamaica and Florida deteriorate and we think we know what is happening there," Hochberg added. "However, reefs respond in complex ways to environmental stresses such as sea level change, rising ocean temperatures and pollution. The available data were not collected at the appropriate spatial scale and density to allow us to develop an overarching, quantitative model that describes why and how reefs change in response to environmental changes. We need accurate data across many whole reef ecosystems to do that."

Michelle Gierach, a CORAL project scientist at NASA's Jet Propulsion Laboratory (JPL) in California, explains PRISM was designed for remote sensing of coastal and inland waters. The spectrometer records the spectra of light reflected upward toward the instrument from the ocean below, allowing researchers to pick out the unique spectral signatures of living corals and algae. The ratio of coral to algae is a good indicator of reef health because algae growth tends to take over dead corals.

"Now, estimates of global reef status are synthesized from local surveys with disparate aims, methods and quality," Gierach said in the release. "With CORAL, we will provide not only the most extensive picture to date of the condition of a large portion of the world's coral reefs, but a uniform dataset, as well."

While CORAL will provide a more accurate picture of reef health and its impending doom, the expedition will only cover three to four percent of the world's reefs.

"Ideally, in a decade or so we'll have a satellite that can frequently and accurately observe all of the world's reefs, and we can push the science and most importantly our understanding even further," Hochberg concluded. 

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