Mathematics professor models the oceans © May 2, 2008 Norwich University Office of Communications

Still from Casco Bay wind and dye current-tracking computer model video

video still courtesy of Ernest TrueStill from a video of dye released into the Kennebec River and spread through Casco Bay by tide and wind during an eight-day period in 2005.Open video

Despite living in land-locked Vermont, Ernest True loves the ocean. You could say it’s in his blood, since he grew up on the rocky Maine seacoast, the grandson of a sea captain.

True moved inland to join Norwich University’s mathematics faculty in 1974, but he has never lost his passion for learning more about the sea’s unique environment. He has used his mathematical skills to develop numerical models of ocean currents, sharing his work with scientists across disciplines, including those from the Woods Hole Oceanographic Institute in Massachusetts, a world-renowned education and research center.

“Ocean currents are like conveyer belts, moving material and marine life along with them,” True said. “I study the patterns that currents create and effects they have on the marine ecosystem.”

True’s current project involves studying Casco Bay on Maine’s coast, which includes Portland Harbor at its heart. Casco Bay is one of the busiest marine areas on the eastern coast. Mapping its currents gives ecologists insights into the ecosystem, including issues such as water quality, the viability of commercial fishing, and the sustainability of plant and marine life.

One of True’s research partners, James Manning, an oceanographer at Woods Hole’s Northeast Fisheries Science Center, believes that studies of Casco Bay will directly affect the local economy and food supply, particularly marine-life populations on which the fishing industry depends. For example, Manning noted, modeling the bay’s currents helps scientists learn more about lobsters, which start life as eggs that hatch into tiny larva swept along by water motion.

“One application that really drove the field from the beginning is the simulations of [lobster] larval transport.” Manning said. “Given that lobsters release millions of eggs into the wild, it is important to understand the transport of these eggs and where they settle after weeks of free-drifting.”

True added, “We know that lobster eggs float in the upper 5 meters of water, so understanding currents helps to discover where the eggs come from, whether from Casco Bay or another source.”

Because nature is mercurial, the work of modelers and oceanographers such as True and Manning is never entirely etched in stone. One example is the effects on Casco Bay two years ago, when May northeaster storms ushered in a wave of red tide. After the algal bloom coated the bay, clam flats could not be harvested. The local fishing economy was devastated, and tourism suffered as restaurants spent extra money importing clams from the Chesapeake Bay.

According to True, ocean models may prove useful for predicting the location and extent of environmental impacts such as the 2006 northeaster. “Knowing how the currents are affected by wind is important,” True explained. “The makeup of the bay water also is changed by fresh-water sources blown in by the wind. This all changes habitat for plankton,” including the phytoplankton that causes poisonous red tide.

I use Professor True as a shining example of what you can do with a degree in mathematics.

~ Gerard LaVarnway
Chair of Norwich University mathematics department

The marine ecosystem also is affected by human activity. Every few years, deep-water ports are dredged. Consequently, “heavy metals enter the marine system in new amounts,” which in turn influences habitats, True said.

The ocean environment is so complex, in fact, that studying it requires the insights of various disciplines. To become competent oceanographers, students must become adept at applied mathematics, fluid dynamics, and computer science. They also need a basic understanding of marine biology, chemistry, and geology, according to Manning. True has logged time alongside specialists in all these disciplines, including collecting data at sea and then analyzing it.

“For about 10 days at a time, marine biologists and oceanographers spend time on a boat working collaboratively,” True said. “We don’t get very much sleep, and it’s very intense, but we get a lot of work done.”

The relevance of True’s work in applied mathematics for oceanography—and the extent of his collaboration with other researchers—are among the reasons that Gerard LaVarnway, chair of the mathematics department at Norwich, uses True as “a shining example of what you can do with a degree in mathematics” when he gives career talks. In fact, Manning believes True’s branch of applied mathematics is becoming even more pertinent as environmental issues rise to the fore nationally.

“Given recent increase in the use of ocean environments for aquaculture, tidal-power turbines, marine sanctuaries, and other activity, the demand for ocean-circulation models is growing and will only continue to grow,” Manning said.