When it comes to mapping the ocean floor, lasers can capture fine details even better than the sonar. However, while sound waves excel at cutting through dense materials, light waves move best through empty space, making it difficult for lasers to penetrate the ocean's murky depths.

Researchers from Florida Atlantic University's Harbor Branch Oceanographic Institute think it's possible to overcome the problems of undersea laser imaging by deploying swarms of automated robots to do the job.

Working together, these bots could function as a giant laser-imaging network and provide broader, faster coverage of the ocean's bottom. The approach could aid in the identification of objects (such as mines) that endanger shipping and military operations, researchers say.

These robotic laser networks may also provide a more holistic view into the ecology of endangered coral reef habitats, says Fraser Dalgleish, the project's principal investigator and an assistant research professor at Harbor Branch in Fort Pierce, Fla.

In recent years, the U.S. Navy has come under fire because of training exercises involving sonar that whale-lovers charge is deafening marine mammals and, in some cases, leading to their deaths by disrupting their communications and sending them astray. New research suggests that sonar does cause hearing loss, but only when it's extremely loud and extremely close.

Anecdotal evidence abounds of links between sonar training and beachings. For instance, a pod of whales apparently lost their way and washed ashore in the Puget Sound, Wash., in the summer of 2005 following a naval training. But until now, no one had tested the actual impact of the sub "pings" on marine mammals.

Marine biologist Aran Mooney of the Woods Hole Oceanographic Institution and his colleagues report in Biology Letters that they exposed a bottlenose dolphin with an  electro-encephalogram (EEG) strapped on his head to a tape of the sonar sounds from that same Puget Sound exercise—15 sonar "pings" over two minutes—and measured his reaction.

The U.S. Supreme Court in a 5–4 decision today ruled that the Navy does not have to consider the effect of sonar on whales when training with sonar off the coast of California. "The Court does not question the importance of plaintiffs' ecological, scientific and recreational interests, but it concludes that the balance of equities and consideration of the overall public interest tip strongly in favor of the Navy," Chief Justice John Roberts wrote for the majority. "The determination of where the public interest lies in this case does not strike the Court as a close question."

Environmentalists, including the Natural Resources Defense Council, which sued to stop the sonar exercises, and the International Fund for Animal Welfare (IFAW) charged that the high-intensity mid-frequency active (MFA) sonar blankets vast areas of the ocean with noise pollution, causing whales, including endangered beak whales, to beach and/or die. The Navy does not dispute the potential danger to the mammals, acknowledging in its own environmental assessments that the sonar may permanently damage as many as 500 whales and temporarily deafen at least 8,000 whales.