Spiritual Enlightenment Upon the Sea

Jill Rowbotham | September 09, 2009
Article from: The Australian

KELSIE Dadd's chuckle is relayed via satellite from the JOIDES Resolution, in the Bering Sea.

"It's great to be away from all that administrative work," Macquarie University's head of earth and planetary sciences says. It would be difficult to be further distant, given she is somewhere in the high 50 degrees latitude and 170 degrees longitude, not far from the date line.

Dadd, a geologist, is on a two-month voyage on the 143m research vessel, which was formerly used for oil exploration.

It sailed from Victoria, in Canada, with more than 40 other scientists on board. Their mission is to drill cores from the ocean floor, examine them in ship-based laboratories and transport them safely to labs ashore.

"One of the main aims of the cruise is to generate more information to try to understand the climate history of the last five million years," Dadd says.

The voyage is part of the International Ocean Drilling Program, which takes samples from the seafloor across the world in a bid to advance understanding of the earth's history, including its ocean currents, climate, plate tectonics, evolution and extinction of marine life and mineral deposits.

A collaboration between universities and research institutes, and based at the Texas A&M University in Houston, the IODP keeps the JOIDES Resolution on the water year-round. Australia is allocated six positions annually, for which scientists must apply.

Dadd's specialty is vulcanism, so this trip suits her perfectly: she is focusing on the volcanic Aleutian archipelago that stretches 1800km west from the Alaskan coast. It is the southernmost limit and cradle of the Bering Sea.

She wants to establish if the varying amounts of volcanic ash of different compositions in the core samples can be linked to rapid climate change in the past.

While Dadd is not suggesting ancient eruptions in the Aleutians were main contributing factors to climate, she notes that "ash and especially sulphur dioxide gets into the atmosphere and blocks the in-coming sun", which has short-term effects.

Recent eruptions have famously altered climate, albeit briefly. When The Philippines' Mt Pinatubo erupted in 1991, it was followed by a 0.5 degree drop in temperature and the 1815 eruption of Mt Tambora in Indonesia was followed by what was known as "the year without a summer".

The scientists are particularly interested in what the extracted material will reveal about the 40,000-year cycles of glacial and interglacial periods in the north Pacific and globally.

"When there is a glacial period, sea level is much lower than in the interglacial period because the water turns to ice, and in those times much of the Bering Sea was land," Dadd says.

The holes drilled so far already number more than two dozen and include one taken in water 3000m deep, drilled to a depth of 700m into the seabed.

The cores will stay at Kochi, Japan, after the ship docks at Yokohama, and Dadd will make another trip to Kochi to study them in November or December.