Exploration of a Submerged Sinkhole Ecosystem in Lake Huron

Abstract

Dissolution of the Silurian-Devonian aquifer in the Lake Huron Basin has produced several karst formations in the bedrock (sinkholes), through which groundwater emerges onto the lake floor. During September 2003, we explored a recently discovered submerged sinkhole ecosystem (55 m · 40 m · 1 m) located at a depth of 93 m with a remotely operated vehicle (ROV) equipped with a conductivity-temperature-depth (CTD) system, an acoustic navigational system, a video camera, and a water sampling system. In addition to two morphotypes of benthic mats, a 1-2 m thick visibly cloudy near-bottom nepheloid-like layer (sinkhole plume) with a strong hydrogen sulfide odor prevailed just above the seepage area of clear water. Relative to lake water, water samples collected within the sinkhole plume were characterized by slightly higher (by 4°C) temperatures, very high levels of chloride (up to 175 mg l )1 ) and conductivity (1,700 lS cm

Bacterial and Archaeal Phylogenetic Diversity of a Cold Sulfur-Rich Spring on the Shoreline of Lake Erie, Michigan

“…If epsilonproteobacteria similar to those detected at the GSS spring origin also exist in the aquifer itself, sulfuric-acid speleogenesis may be an important microbially mediated limestone dissolution process contributing to the development of karst features in the area and influencing the variable occurrence (and hence, suitability for drinking) of H 2 S in Monroe County groundwater. Additionally, plumes of high-conductivity, anoxic groundwater from the Silurian-Devonian aquifer, enriched in sulfate, sulfide, and nutrients and surrounded by whitish filamentous materials and variously colored microbial mats (referred to as biogeochemical hotspots), have been reported to occur near submerged sinkholes at 93-m depths in Lake Huron (2,49). The present study of GSS hints at many types of biogeochemical functions for such groundwater seeps at depths in the Great Lakes.…”

“…SO 4 2Ϫ becomes available for microbial reduction to sulfide in aquifer zones where conditions are appropriate. Where spring waters rich in CaCO 3 , CO 2 , and sulfide emerge at the surface, carbonate deposition and microbially mediated sulfide oxidation occur. These processes result in tufa deposits and the whitish crusts often noted in sulfidic spring outflows (12,13).…”

“…A cold, sulfidic spring is located in Ancaster, Ontario, about 5 km from the Lake Ontario shoreline (13). Recently, plumes of high-conductivity sulfidic groundwater, surrounded by whitish filamentous materials and variously colored microbial mats, were reported to occur at a 93-m depth in Lake Huron (2,49). However, there have been few molecular surveys of Bacteria or Archaea in any Great Lakes environment, and no reports focusing on the molecular phylogenetic diversity of microorganisms associated with these Great Lakes sulfidic environments.…”

From land to lake: Contrasting microbial processes across a Great Lakes gradient of organic carbon and inorganic nutrient inventories

“…So the input from high-productivity drowned river mouths and upstream sources of organic and inorganic nutrients are critical factors in the dynamics of this changing ecosystem. Much remains to be described about the composition of land-to-lake planktonic microbial communities and the processes or mechanisms by which they survive and proliferate (Wetzel, 2001;Keogh et al, 2003;Biddanda et al, 2006;Newton et al, 2011).…”

A bibliometric analysis of scientific trends in phytoplankton research

“…Moreover, some collaborative publications are associated with geographic locations. For example, the researches about Laurentian Great Lakes basin promoted the cooperation of the USA and Canada (Biddanda et al, 2006;Lunetta et al, 2010). Other countries with frequent cooperation were also generally geographical neighbors.…”