Distribution of Organic Carbon in the Berkeley Pit Lake, Butte, Montana

Abstract

The concentration of dissolved organic carbon (DOC) in the Berkeley pit lake water ranges from 2 to 4 mg/L, and is comparable to that of its inflow waters. On the dates sampled, the DOC concentrations decreased towards the surface of the lake, in a manner similar to the concentration of dissolved Fe. This may reflect adsorption of DOC onto newly formed ferric precipitates in the epilimnion of the lake. The total organic carbon (TOC) content of the lake sediment is 0.20 to 0.33%, and is on the low end of TOC in natural aquatic sediments. In contrast, the DOC concentrations of sediment pore waters are unusually high, ranging from 50 to 380 mg/L, and are much higher than DOC values of pore waters from typical marine or lacustrine sediments. The high DOC concentrations are explained by release of adsorbed organic carbon from ferric precipitates as they age and recrystallize, coupled with the relative scarcity of heterotrophic bacteria in the acidic and heavy metal-rich waters that would otherwise consume DOC through reduction of sulfate.

Archive of bacterial community in anhydrite crystals from a deep-sea basin provides evidence of past oil-spilling in a benthic environment in the Red Sea

“…The geochemical data collected herein suggested that the sub-superficial anhydrite layer could release organic carbon contents into the sediment, as reported previously. Our measurement of DOC at 80.9 mg L −1 in the anhydrite layer was higher than the generally accepted maximum value of 50 mg L −1 for marine sediments (Cameron et al, 2006). The abnormally high DOC was considered a notable alteration of the local environments and probably resulted from the breakdown of anhydrite crystals.…”

“…Most of the dead microbes are damaged during the sedimentation process, but some can be maintained in almost their original shape (Taher, 2014;Benison et al, 2008). Evaporites, which mostly consist of halite and anhydrite (CaSO 4 ) or gypsum (CaSO 4 × 2H 2 O, temperature < 38 • ; Hill, 1937), are common microbialites with accretionary organosedimentary structures (Dupraz et al, 2011). Numerous dead bacteria, algae and metazoans have been detected in gypsum granules (Petrash et al, 2012;Trichet et al, 2001); bacterial mats growing on evaporites may become trapped and constitute much larger microbialites (Babel, 2004).…”

Physico-chemical gradients and meromictic stratification in Cueva de la Mora and other acidic pit lakes of the Iberian Pyrite Belt

“…A similar process could result in releases of phosphate and organic carbon, both of which adsorb strongly onto freshly precipitated ferric oxides at low pH (e.g. Cameron et al 2006;Spiteri et al 2008; see references cited therein). Elevated concentrations of phosphate and TOC have been detected in mine drainage minerals in the IPB (0.10-0.30 wt% P 2 O 5 and 0.40-1.40% C org , Sánchez-España et al 2006b, 2007b.…”

Photochemical degradation of natural organic sulfur compounds (CHOS) from iron‐rich mine pit lake pore waters – an initial understanding from evaluation of single‐elemental formulae using ultra‐high‐resolution mass spectrometry

“…DOM cycling in pit lakes is highly influenced by the chemical and stratification conditions in such lakes; the DOC content is high in pit lake pore waters36, 37 and monimolimnion waters, moderate to low in hypolimnion waters and extremely low in epilimnetic and/or mixolimnion waters 16. Pore waters and monimolimnion waters are generally anoxic and rich in Fe(II).…”