Deep Lake Huron Sinkholes

Joe Hoyt, sets up a respiration chamber experiment near the purple microbial mats

Underwater explorer gathering data.

From July 2008 to July 2009, the Thunder Bay Sinkholes project team will explore shallow and deep coastal sinkholes in order to understand the chemical and physical properties that contribute to the unique ecology found in these systems. This multi-investigator team will gather data on the hydrology (the flow rates and dispersion of groundwater), biology, and chemistry from submerged groundwater vents located within the boundaries of the Thunder Bay National Marine Sanctuary, in northwestern Lake Huron.

Figure 2. ROV image of sediment surface of the deep, aphotic Isolated Sinkhole showing the brown and grey mats and a near-bottom nepheloid layer (Biddanda et al., 2006). Left Panel: ROV-video still images of conspicuous benthic grayish-white and brown mats, composition unknown; Right Panel: ROV image of sediments and exposed logs in Isolated Sinkhole (93 meters).

Sinkholes in Lake Huron.

During the project, the team will collect benthic (bottom) samples of the unusual microbial mats growing in very low oxygen conditions to determine how groundwater chemistry allows them to thrive. Samples of these microbial mats will also be analyzed for their potential application as pharmaceuticals. A long-term understanding of the groundwater’s chemical and physical characteristics, such as conductivity (an indication of the presence of ions), temperature, and flow, will be obtained from a moored hydrographic instrument array. Mapping of chemical and biological characteristics over large spatial areas will done using underwater remotely operated vehicles (ROVs) and diver-led sample collection work.


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