Jacques Cousteau would have been proud. To protect coral reefs at the bottom of the sea, marine biologists today have gone to the very heights of modern science. They've gone to outer space. Sounds odd, but it's true. Across the reefs of Florida and Hawaii and several U.S. territories and commonwealths, scientists have compiled satellite images of coastlines. Marine biologists are using those photos to create detailed, digital maps of coastal sea habitats. The initiative, being pursued by the U.S. Coral Reef Task Force, will help resource managers leap forward in coral reef management, providing a major new tool to keep track of coral reef health and environmental impacts, marine biologists say. Digital mapping Here's how it's done. First, satellite pictures of an area's reefs and coastlines are purchased from a satellite company, said James Byrne, a technical assistant with the National Oceanic and Atmospheric Administration. Byrne, who is on island working with local agencies to develop digital coral maps of Guam, said scientists then pick a pilot site to survey and correspond what they find in the sea with what the satellite photos depict. For instance, a certain color patch might consistently indicate sea grass, another patch, coral, in enough detail that the dominant species can be identified. That data is then used to devise a system to determine from satellite photos what kind of habitats exist in other areas. If the system is tuned correctly, experts can map coral and other sea habitats from their desks, Byrne said. Satellite images would then give resource managers and researchers the ability to create digital databases on areas that aren't accessible to people to get into the water to survey reefs. Once the method is ironed out, officials can repeat it over and over after buying more satellite photos. That way, reefs can be monitored -- although field studies will always be used for more in-depth information -- over time for changes in the habitat's health. For example, managers can track the effects of oil spills or soil erosion from the sky as well as from the land. They also can use maps to determine the exact extent of damage. As technology improves, more time could be saved if software is developed that can accurately do the same analysis simply by entering photos into the system, Byrne said. The software is about 60 to 70 percent accurate today. On Guam, the maps are expected to be completed in about a year and a half. | | This image of the French Frigate Shoals in the Northwestern Hawaiian Islands group was taken by the Landsat 7 satellite. Launched in 1998, Landsat 7 circles the earth at an altitude of 705 kilometers. The detailed imagery from Landsat 7 helps scientists conduct preliminary mapping and evaluation of remote coral reefs. Without this valuable tool, examining these remote reef sites would require a significant investment of time and money. Similar projects are being funded and operated by the federal government in cooperation with local governments in Hawaii, the Commonwealth of the Northern Mariana Islands and American Samoa. Mapping projects already have been completed in Florida, the U.S. Virgin Islands and Puerto Rico, Byrne said. It is anticipated that in a short time the Federated States of Micronesia and the republics of Palau and the Marshall Islands will be added to the mapping project. One major reason the project has picked up speed in recent years is the declining cost of satellite photos, said Evangeline Lujan, geographic information systems manager for the Guam Bureau of Planning. The federal government paid about $60,000 for the photos used by Guam, and that price continues to drop as more satellite companies are launched. In the past, the only way to get similar maps was by plane, a vastly more expensive process, Lujan said. The return on the satellite photos is mammoth. From giving teachers CD-ROMs with all the maps and information at a level children can understand, to informing politicians of reef issues, the maps are miles ahead of current data. The last atlas of Guam's reefs was completed in 1976 and has hand-drawn pictures. Lujan said once satellite images are purchased, they can be used by any government agency.Pointing inland to a photo of an area where red erosion burns could be seen abutting native forest, Lujan said land management agencies can tap into the technology as well. "There are so many applications," Lujan said. SOURCE - PDNSCUBA FORUMDISCUSS THIS TOPIC - Dive in and have your say at Scuba Forum |
