B.A. Biddanda Craig A. Stricker S.C. Nold Sanders T. Garrison 2011 <p><span>Groundwater can be an important source of nutrients and energy to aquatic ecosystems, but quantifying the inputs and biogeochemical importance remains challenging. A series of submerged groundwater vents in northern Lake Huron were examined to determine the linkage between groundwater nutrients and aquatic food webs. We collected samples of key food-web components from groundwater vent and reference habitats and analyzed them for&nbsp;</span>¹³<span>C,&nbsp;</span>¹⁵<span>N, and&nbsp;</span>³⁴<span>S isotopes. Dissolved inorganic carbon (DIC) in the groundwater was depleted in&nbsp;</span>¹³<span>C, while aqueous sulfate was enriched in&nbsp;</span>³⁴<span>S (mean differences between groundwater and reference sites were –3.9‰ and +12.0‰, respectively). Benthic primary producers, macroinvertebrates, and benthivorous fish had significantly lower δ</span>¹³<span>C values in groundwater environments, and benthivorous fish were somewhat depleted (–2.5‰) in δ</span>³⁴<span>S at groundwater sites compared to reference sites. However, δ</span>¹⁵<span>N values were not different between groundwater and reference sites, and pelagic components of the ecosystems (plankton and planktivorous and piscivorous fish) were similar in both δ</span>¹³<span>C and δ</span>¹⁵<span>N. These data suggest benthic metazoan communities surrounding groundwater vents are partially linked to groundwater-derived benthic primary production, while planktivorous and piscivorous communities not directly associated with the benthos do not rely on groundwater nutrients.</span></p> application/pdf 10.3354/ab00318 en Inter Research Science Publisher Benthic macroinvertebrate and fish communities in Lake Huron are linked to submerged groundwater vents article