National Geographic features University of Miami's work on Bahamas 'blue holes'

The cover story of the most recent issue of National Geographic Magazine (August 2010) features a University of Miami (UM) led expedition to the underwater caves of the Bahamas, known as 'blue holes.' These unique environments are one of the least understood ecosystems on the planet, largely due to the challenges involved in studying these extreme environments, which include complete darkness, dramatic reversing currents, extreme depths, poisonous gasses, and silty, tight squeezes. The expedition made significant findings related to the past history of the earth, including human occupation, previously undiscovered microbial life, and abrupt climatic changes. The expedition was conceived of and led by National Geographic Emerging Explorer Kenny Broad, Director of UM's Leonard and Jayne Abess Center for Ecosystem Science and Policy, and Associate Professor at UM's Rosenstiel School of Marine and Atmospheric Science. Funded by The National Geographic Society, the National Museum of the Bahamas, and the National Science Foundation, this work included more than 150 dives and involved unique collaboration between cave divers, scientists from several different fields, and a specialized film team led by the late Wes Skiles, a renowned filmmaker, conservationist and cave explorer. The expedition also was featured in a one-hour NOVA PBS special entitled "Extreme Cave Diving."

"What may look like an insignificant little muddy hole in the woods is actually a window into a world we know little about, a time capsule of evolutionary history that not only provides us with information about where we came from, but what surprises the climate may have in store for us," said Broad. "In addition to the scientific value of these caves, underground aquifers are critical reservoirs of fresh water on a global scale. Like many out of sight -out of mind situations, they are largely ignored, and are threatened by overuse, pollution and increasingly, sea-level rise."

Broad worked closely with UM colleagues and students, including geochemist and professor Peter Swart, whose focus was dating and isotopic analysis of stalagmites to reconstruct past climate changes back nearly 500,000 years and Amy Clement, associate professor of meteorology and physical oceanography, who was analyzing this data in the context of current theories on abrupt climate change. Several UM students were also involved in the expedition, including Monica Arienzo, a marine geology and geophysics Ph.D. student analyzing geological samples that include Saharan dust found deep underwater, Bahamian native Nikita Shiel-Rolle, a marine science undergraduate and cave diver who worked on the unique microbiology in these holes, and Colton Hoover Chase, an aspiring filmmaker, who assisted the National Geographic film team.

"The isolated nature of the Bahamas, free of any input from rivers, makes it an ideal place to study the flux of atmospheric-derived dust," said Swart. "As the stalagmites can be dated very accurately, we can examine for the first time the relationship between dust and abrupt climate change in the sub-tropics, and whether the sub-topics may be the actual driver of climate change."

Other key team members included Dive Safety Office and explorer, Brian Kakuk, and Project Coordinator Nancy Albury from the National Museum of the Bahamas, led by Dr. Keith Tinker. University members included astrobiologist Jenn Macalady from Pennsylvania State University, who studied water chemistry and microbes found in the different blue holes, biologist and cave explorer Tom Ilffe of Texas A&M University, who studies extremophile living creatures that live in the submerged caves, David Steadman, professor and curator of ornithology at the Florida Museum of Natural History and a world leader in studying extinct species, and archeologist and cave diver Michael Pateman from the National Museum of the Bahamas, who was excavating and studying the remains of Lucayan indians found in this deep, anoxic environment, which is ideal for the preservation of organic materials.

Source: University of Miami