Physical, chemical, and microbial feedbacks controlling brine geochemistry and lake morphology in polyextreme salar environments

Oehlert, Amanda M.; Suosaari, Erica P.; Kong, Tianshu; Piggot, Alan M.; Maizel, Daniela; Lascu, Ioan; Demergasso, Cecilia; Chong, Guillermo; Reid, R. Pamela

doi:10.1016/j.scitotenv.2022.155378

Cited by 5 publications

(12 citation statements)

References 134 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…As EC increased, microbial mat substrates became less flocculent and more cohesive, with similar microbially influenced minerals. Ponds with the highest EC values lacked microbial mats and were associated with gypsum spar as the dominant bottom type [3,5]. As such, their results suggested that bottom types might be useful as a "visual representation of both the environmental gradients and likely spatial heterogeneity in mineral deposition" [3].…”

Section: Introductionmentioning

confidence: 99%

“…Most of the smaller ponds are located between Puquio 1 and Puquio 2, in a region termed the "Transition Zone" (Figure 1). A strong gradient in water chemistry and diverse bottom types are exhibited between Puquios 1 and 2 [3][4][5]. This sub-system, consisting of two main lakes and the smaller ponds characteristic of the Transition Zone are designated as the P1/P2 subsystem, and it is the focus of the present study.…”

Section: Introductionmentioning

confidence: 99%

“…This sub-system, consisting of two main lakes and the smaller ponds characteristic of the Transition Zone are designated as the P1/P2 subsystem, and it is the focus of the present study. The ponds in the P1/P2 subsystem are all hydrologically connected, with ground water flow from southwest to northeast, and increasing EC from P1 to P2 [3][4][5]. Evaporation and subsurface water-rock interactions significantly influence brine composition across this gradien [4][5][6][7].…”

Section: Introductionmentioning

confidence: 99%

“…The ponds in the P1/P2 subsystem are all hydrologically connected, with ground water flow from southwest to northeast, and increasing EC from P1 to P2 [3][4][5]. Evaporation and subsurface water-rock interactions significantly influence brine composition across this gradien [4][5][6][7]. Across this gradient, Reid et al [3] and Oehlert et al [5] observed a variety of microbial and crystalline bottom types that could be correlated with the EC.…”

Section: Introductionmentioning

confidence: 99%

“…Evaporation and subsurface water-rock interactions significantly influence brine composition across this gradien [4][5][6][7]. Across this gradient, Reid et al [3] and Oehlert et al [5] observed a variety of microbial and crystalline bottom types that could be correlated with the EC. Ponds with relatively low EC values typically had flocculent microbial mat substrates with microbially influenced gypsum, carbonate and clay minerals.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Environmental and Biological Controls on Sedimentary Bottom Types in the Puquios of the Salar de Llamara, Northern Chile

et al. 2022

Self Cite

View full text Add to dashboard Cite

The Puquios of the Salar de Llamara in the Atacama Desert, northern Chile, is a system of small lakes that is characterized by evaporitic mineral deposition and that commonly hosts microbial communities. This region is known for its extreme aridity, solar irradiance, and temperature fluctuations. The Puquios are a highly diverse ecosystem with a variety of sedimentary bottom types. Our previous results identified electrical conductivity (EC) as a first-order environmental control on bottom types. In the present paper, we extend our analysis to examine the effects of additional environmental parameters on bottom types and to consider reasons for the importance of EC as a control of sedimentology. Our results identify microbially produced extracellular polymeric substances (EPS) as a major player in the determination of bottom types. The relative amounts and properties of EPS are determined by EC. EPS, in turn, determines the consistency of bottom types, exchange of bottom substrate with the overlying water column, and mineral precipitation within the substrate. Low-EC ponds in the Puquios system have flocculent to semi-cohesive bottom types, with low-viscosity EPS that allows for high-exchange with the surrounding waters and mineral precipitation of granular gypsum, carbonate, and Mg–Si clay in close association with microbes. Ponds with elevated EC have bottom types that are laminated and highly cohesive with high-viscosity EPS that restricts the exchange between sediments and the surrounding waters; mineral precipitation in these high-EC ponds includes granular to laminated gypsum, carbonate and Mg–Si, which also form in close association with microbes. Bottom types in ponds with EC above the threshold for thriving benthic microbial communities have insufficient EPS accumulations to affect mineral precipitation, and the dominant mineral is gypsum (selenite). The variations in EPS production throughout the Puquios, associated with heterogeneity in environmental conditions, make the Puquios region an ideal location for understanding the controls of sedimentary bottom types in evaporative extreme environments that may be similar to those that existed on early Earth and beyond.

show abstract

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%