Large Lakes Observatory

R/V Blue Heron

The Large Lakes Observatory operates the largest university-owned research vessel in the Great Lakes, the R/V Blue Heron . Built in 1985 for fishing on the Grand Banks, the Blue Heron was purchased by the University of Minnesota in 1997, sailed from Portland, Maine, up the St. Lawrence Seaway to Duluth, and converted into a limnological research vessel during the winter of 1997-98. She is outfitted with state-of-the-art research equipment that is described below. The Blue Heron has berthing for 9 crew and scientists, and can operate 24 hours per day for up to 14 days in between port calls. The Blue Heron is part of the University National Oceanographic Laboratory System (UNOLS) , and is available for charter by research scientists on any of the Great Lakes.

The LLO also operates the R/V Noodin , a smaller (25') vessel that is available for work on the Great Lakes during favorable weather conditions, the St. Louis estuary, and smaller lakes.

The geophysical equipment available on the Blue Heron for lake floor mapping and sub-bottom characterization is extensive. This equipment includes a Knudsen echosounder (28kHz), a Geopulse seismic reflection profiling system (1-3kHz) for high resolution, shallow penetration images of the sub-bottom, and a set of airguns for low resolution, deep penetration images of the sub-bottom. Also available are a Edgetech sidescan sonar/CHIRP system and a Reson Multi-Beam sonar system coupled with a POS-MV motion sensing system, allowing very precise swath mapping of lake floor bathymetry in water depths up to 300m.

The Blue Heron also has a broad suite of equipment for the physical and geochemical study of the water column. This equipment includes a SeaBird 911+ CTD and Carousel sampler for determining temperature, salinity, chlorophyll concentration, transparency, dissolved oxygen content and pH of the water column as well as sampling water at desired depths using Niskin bottles. A SeaBird 19 CTD for measuring temperature, salinity, chlorophyll concentration and transparency is available as a backup to the 911+ or for work off of the R/V Noodin. In addition, we have available a Maclane in situ filtration system.

The R/V Blue Heron is unique among Great Lakes research vessels in having an Acoustic Doppler Current Profiler (ADCP) as well as a Triaxus. The ADCP is used to measure current speed and direction (both horizontally and vertically) in 2 m increments throughout the water column while the ship is underway. The Triaxus is a towed vertically undulating vehicle with an extensive instrument package that can measure temperature, salinity, chlorophyll concentration, transparency, dissolved oxygen content and plankton size and distribution.

Users of the Blue Heron also have a broad set of sediment and biological sampling gear available to them. Sediment sampling gear includes a grab sampler, gravity corer, multi-corer, and piston corer. Biological sampling gear includes plankton nets and a 60' Stauffer midwater trawl with a trawl sonar system.