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The University's Ship
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The Blue Heron leaves the Grand Banks for Gitche Gumee
The Large Lakes Observatory (LLO) at the University of Minnesota, Duluth, (UMD) is the only institute in the country dedicated to studying large lakes worldwide. The term for its work is limnology, a less-than-household word meaning “the scientific study of bodies of fresh water.” LLO’s research ranges from lakes in the East African Rift Valley and central Asia, to the Great Lakes of North America.
In 1997, LLO took a bold move and bought an 87-foot stern trawler to be converted for research on Lake Superior. The trawler, originally named the Fairtry, was built in a down-east shipyard in 1985, and was one of the fairest of the fishing boats on the Portland, Maine, waterfront. But fish stocks were being overharvested on the Grand Banks, and the owner of the Fairtry decided to get out of the business and sell off his boats.
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| The Blue Heron heading out into Lake Superior on an August morning.or |
Turning fish holds into labs
The trawler was renamed the R/V (for research vessel) Blue Heron. The Blue Heron was refitted in a Superior, Wisconsin, shipyard shortly after her arrival in Duluth. Workers sandblasted and repainted her hull and installed new transducers for acoustic remote sensing. They converted deck space and fish holds into laboratories, put in new deck equipment for deploying instruments over the side, and thoroughly cleaned and repainted the living spaces. The rusty old trawler metamorphosed into a clean new research vessel. LLO scientists acquired more than
Professor Elise Ralph, for example, is examining the dynamics of shallow and deep water currents and the thermal structure of the lake. (It’s warming up, she’s discovering, most likely as a result of global warming.)
$400,000 worth of sophisticated instrumentation for the Blue Heron with National Science Foundation grants and matching funds generously provided by the Graduate School. The Blue Heron is now the largest and best equipped university research vessel on the Great Lakes.
The R/V Blue Heron spends about 100 days a year on Lake Superior, carrying faculty, students, and technicians from LLO and other UMD and Twin Cities campus departments. Scientists from other universities around the country use the Blue Heron for their research needs on Lake Superior as well. The ship typically stays for a week at a time, working 24 hours a day, making a variety of measurements. Nine berths on board accommodate the four professional crew and the scientific party of five. The boat is completely self-supporting. All operating costs are covered by user fees provided primarily by federal research grants.
What lies beneath
Scientists on the Blue Heron undertake a broad spectrum of investigations with the able assistance of their “seagoing” graduate and undergraduate students. Professor Elise Ralph, for example, is examining the dynamics of shallow and deepwater currents and the thermal structure of the lake. (It’s warming up, she’s discovering, most likely as a result of global warming.) Professors Nigel Wattrus and Tom Johnson found that the deepest hole in Lake Superior (about 1,276 feet) is not a quiet environment in which fine sediment placidly settles out on the lake floor. It’s a sandy site with bold sandstone outcrops nearby. Deepwater storms occasionally pass by, sweeping the floor clear of any recently deposited sediment. The origin, duration, and frequency of these storms is unknown.
Professor Jim Cotner from the Department of Ecology, Evolution, and Behavior on the Twin Cities campus is teaching students to think small with this huge lake. His research suggests that the ecosystem is completely dominated by bacteria and algae that are smaller than one micron (or .00004 inch) in diameter, and Professor Meng Zhou is finding that the abundance and size of zooplankton (microscopic-sized crustaceans) strongly resemble the very productive sea off northern California.
Professor Erik Brown is tracking the behavior and fate of trace metals in the lake floor sediments, focusing mainly on copper derived from mining operations in upper Michigan and on lead derived from gasoline additives. Professor Jim McManus deploys sediment traps in the water column off Split Rock Lighthouse to determine the seasonal variability in abundance and composition of sediments raining down upon the lake floor. These discoveries aboard the Blue Heron raise interesting new questions about the Lake Superior ecosystem—questions that underline the need for this valuable research vessel for decades to come.
—Large Lakes Observatory