In Mexico, resort hotels and restaurants are permitted to drill holes into the bedrock and pump human waste from septic tanks into the holes, says Abigail Alling, director of the Planetary Coral Reef Foundation, Bonsall, Calif.
The bedrock along the Yucatan coast consists of porous limestone that allows the sewage to seep out into the water along its once-pristine beaches.
The sewage pollutes the coastal water, and its high content of phosphorous and nitrogen damages the coral reefs.
"The problem in Yucatan is that just a few decades ago, you had a population under 30,000 people.
Now there are 3 million additional visitors per year, and sewage is being pumped nonstop down the holes," Alling
says the governments of Egypt, Maldives, Kenya, Australia, Bali and Israel also are planning to construct the systems.
says the foundation's interest in promoting the system is in preserving coral reefs.
It is using money made from sales of the systems to fund the nonprofit group's other scientific projects.
Coral reef clues
Nelson and Alling
combined their interests after the Biosphere
2 project, in which they and six other people lived in a closed ecological environment for two years.
Alling, who was scientific director of the Biosphere project, managed a living coral reef inside one of the Biosphere's domes.
During the two-year stay, Alling
says, the coral reef became the canary of the coal mine.