During the past 25 years, corporations have plumbed the depths of the Arctic Alaskan mainland for oil, collecting more than 13 billion barrels in the process. More recently, these companies expanded efforts to include offshore drilling. Trefry and his Florida Tech team, Steven Wood, assistant professor of oceanography, Bob Trocine, senior research associate, Robert Rember, research scientist, and graduate students Michelle McElvaine, Lee Frey, and Debra Woodall were funded by the department's Minerals Management Service to learn if this new drilling was causing negative impacts on the environment. Trefry's research has been extensive.
"We analyzed several species of fish, clams and amphipods," said Trefry. "We also studied the water, ice and mud to check for potential pollution." What Trefry's team and their colleagues from Battelle Ocean Sciences, Kinnetics Laboratories, Applied Marine Sciences and the University of Texas Marine Lab discovered through their analyses was a pleasant surprise. "We found early in the process that impacts to the environment from offshore drilling were minimal," Trefry said. "In fact, the entire offshore area was near pristine. During the past four years we've continued to monitor the area and still have no evidence of significant impacts."
After the first year, Trefry reoriented the program from being solely an impact study to one that would investigate the natural oceanographic system of the Alaskan Arctic. Trefry spent much of the next three springs and summers in the area, studying how the summertime melt on the mainland affected the surrounding ocean.
"Starting in late May of 2001 and 2002 we began intensive daily sampling at three rivers, trying to understand the input of dissolved chemicals and suspended sediments into the ocean," said Trefry. "What we found was that more than 80 percent of the sediment that enters the ocean over the course of the year comes in a single two-week period."
This late May meltdown arrives early enough in the year to meet unusual resistance. The Artic Ocean at that time of year is topped with a six-foot layer of ice. As a result, the freshwater runoff has no way to merge into the saltwater ocean.
"The freshwater runs out over and just under the ice. The ocean water is so cold (30.8 degrees F) that any freshwater that flows underneath the six-foot top layer, is quickly trapped by a second, thinner layer of ice beneath the flow," he said.
The freshwater runoff stretched out at least 10 miles from the mainland without mixing with the ocean waters below. This discovery explained two environmental phenomena.
First, rivers normally introduce large amounts of nitrogen and phosphorous into the ocean. This introduction leads to plankton blooms. Trefry and his team now had a tangible reason for the late growth of these blooms in the Arctic Ocean. Second, they gained a greater understanding of why the ocean was still in near-pristine condition after years of oil-drilling. Trefry said that they were no longer surprised by their first-year results.
"What we came to realize is that extreme caution by industry, combined with movement of water and sediment offshore, help keep the coastal system clean," he said.
Journal
Environmental Geology