http://www.rgj.com/article/20090501/NEW ... /1321/NEWS
May 1, 2009
Tahoe submarine dive starts 5-year global research
By Jeff DeLong
A small submarine slipped below the surface of Lake Tahoe on Thursday, beginning a monthlong study of its depths that will be followed by a global underwater adventure.
The dive Thursday off the shore of South Lake Tahoe essentially was a shakedown mission for others planned in May around Tahoe and in nearby Fallen Leaf Lake.
The first manned submarine to research Tahoe's depths in many years will help researchers learn more about earthquake faults, ancient submerged forests and invading creatures threatening the lake's future.
Other submerged mysteries could emerge as well.
"There are a lot of things that haven't been seen in this lake," said Scott Cassell, president and founder of the nonprofit Undersea Voyager Project. "There are large portions of this lake that have yet to be seen."
Cassell, a veteran diver and underwater explorer who recently gained fame as the first person to successfully film a giant squid in its natural environment, called Tahoe a natural place to begin years of planned studies of the planet's oceans.
"Lake Tahoe is a treasure in the United States, and that's why we're here," Cassell said. "Lake Tahoe is almost an inland sea. It has a beautiful ecosystem all it's own, and it's in trouble."
The SeaMagine submarine SeaMobile, which can carry a pilot and observer, will plunge up to 150 feet, the maximum depth at Tahoe's high altitude that divers can safely recover the sub and its occupants. Cassell and colleagues hope to obtain a remote-controlled robotic submersible later this month that will allow studies all the way down to Tahoe's bottom, or more than
1,600 feet below the surface at its deepest.
Examination of three underwater fault lines that triggered large earthquakes thousands of years ago, at least in one case causing a massive tsunami that damaged much of Tahoe's shoreline. Scientists hope for information that might help determine when future earthquakes will occur, Cassell said.
The sub will cruise past submerged forests in Lake Tahoe and Fallen Leaf Lake, where trees as old as 3,000 years exist.
Exploration will aid research into the suspended particles and algae that steadily eroded Tahoe's famed clarity over the last four decades, a phenomenon associated with human activity around the lake.
Research will be conducted into invasive species threatening Tahoe, including beds of Asian clams found in certain areas. Some experts fear the clams could make Tahoe more vulnerable to establishment of quagga or zebra mussels, which could cause major ecologic and economic damage.
Invasive species pose a "huge threat" to the lake, and it is hoped that information learned through the Undersea Voyager Project can make a significant difference in reducing that danger, said Julie Regan of the Tahoe Regional Planning Agency, which is assisting the effort.
"We have to act and act in a very robust way," Regan said.
After leaving Lake Tahoe, scientists will begin the five-year mission exploring many parts of the world's oceans, using another manned submersible capable of dropping 1,500 feet deep. Crews will study the increasing number of "dead zones" where phosphates and other inorganic toxins are affecting sea life.
Cassell said the oceans are approaching an ecological "tipping point" with profound ramifications for the planet. He said he is hoping the Undersea Voyager Project can help make a difference in keeping oceans healthy.
"People can start to rally together to make changes, so the oceans do not in fact die," Cassell said. "If we can't save Lake Tahoe, what makes us suspect we can save the oceans?"