Featured Site: Venture Deep Ocean

Catherine Williams
June 08, 2005

Biology professor Charles Fisher will spend most of June far from land, leading a research expedition to the Lau Basin between Tonga and Fiji in the South Pacific. The three-week cruise aboard the research vessel Melville is the latest in a series funded by the U.S. National Science Foundation.

The Lau cruise series aims to identify a "bullseye" site for future study by scientists associated with Ridge 2000, a multi-university effort focused on understanding the processes that take place at mid-ocean ridges and related tectonic systems. Geologists, geophysicists, geochemists, microbiologists, physiologists, ecologists and other researchers are collaborating to study the complex relationships between different components of these systems: rocks in the Earth's mantle and crust, the hydrothermal fluids emitted by seafloor vents, and the living creatures that survive on chemicals found in the fluids.

Fisher is the current chair of Ridge 2000, and the program office has been located in Penn State's biology department since 2001. Under the Ridge 2000 program, scientists from universities around the U.S. share data and ideas with each other—and this latest cruise is no exception.

As chief scientist for expedition five, Fisher will ensure that the cruise's work complements that of previous expeditions, which mapped the seafloor, identified areas containing hydrothermal vents, studied rocks and water chemistry, sampled for microbes, and collected a range of animals, some which may be new to science. Fisher's cruise will concentrate on sea-floor communities—ecosystems thriving in the dark, thousands of feet deep in the ocean.

Some of the thirty or so international scientists on board will use color cameras attached to a remotely-operated submersible to photograph the sea floor. Images will then be patched together to form detailed mosaics showing hydrothermal vent structures—such as chimneys and smokers—as well as the locations of living creatures. These mosaics will yield baseline data for tracking how the communities of animals living around vents change over time.

Other scientists will make detailed measurements of water chemistry around vents to understand the conditions in which different sorts of animal survive and grow. Yet another team will study live animals brought aboard and placed in special high-pressure aquaria. Researchers from Fisher's lab at Penn State will be deploying temperature probes to record variability in the hydrothermal fluid flow, and will also collect a range of samples to assess which kinds of animals are present in different sea-floor environments. Data from this quantitative sampling will allow them to compare the ecology of the biological communities in this part of the South Pacific with communities from similar areas in other parts of the world.

For more information about the cruise, and the previous expeditions in the series, visit Venture Deep Ocean.

Last Updated June 08, 2005