Geosciences Students Deepen Their Knowledge of Mariana Trench

Editors’ Note: This feature appears as it was published in the spring 2017 edition of UT Dallas Magazine. Titles or faculty members listed may have changed since that time.
Brent Bowers (left) and Diluni Hetti.


Geosciences graduate students Brent Bowers and Diluni Hetti sailed the Pacific Ocean in the fall aboard a deep-sea research vessel as part of a scientific team studying the geology and biology of the Mariana Trench.

The Mariana Trench, located in the western Pacific Ocean just south of Japan, marks a boundary between two slowly moving pieces of the Earth’s crust — the sinking Pacific plate and the overriding Philippine Sea plate. It includes the deepest point in the ocean, Challenger Deep, which extends 7 miles down.

The students, neither of whom had been to sea before this voyage, joined a research team that included geologists, biologists and microbiologists. They used a deep-sea, remotely operated submersible vehicle to study the seafloor at a maximum depth of more than 4 miles. The research vessel is owned and operated by the Japanese Agency for Marine-Earth Science and Technology. Dr. Asahiko Taira, who earned his PhD in geosciences from UT Dallas in 1976, is president of the agency.

“The goal of this research cruise is to study an unusual field of hydrothermal vents near Challenger Deep,” said Dr. Robert Stern, professor of geosciences, before the trip. Stern leads the University’s participation in the Mariana Trench research group.

The vent field, known as the Shinkai Seep Field, is located about 3 miles below the ocean’s surface. It was discovered in 2010 by a joint Japanese-U.S. research team that included UT Dallas geoscientists.

The vents serve as oases in an otherwise lifeless area in the ocean depths, where sunlight does not reach to fuel photosynthesis in plants, and nutrients from dead plants and animals from above are eaten before they can drift down to the seafloor.

Bowers and Hetti used the submersible vehicle to study and sample geological formations and biological communities in the vent field, including colonies of large vesicomyid clams that the joint Japanese-U.S. team discovered living there in 2010.