Quantifying, assessing and removing the extreme gas load from meromictic Guadiana pit lake, Southwest Spain

Boehrer, Bertram; Yusta, Iñaki; Magin, Katrin; España, Javier Sánchez

doi:10.1016/j.scitotenv.2016.04.118

Cited by 19 publications

(21 citation statements)

References 32 publications

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“…The observed N 2 ebullition flux of 4.7 ± 3.6 mmol N 2 m −2 d −1 would have dropped the N 2 partial pressure in the water only by a few percent over the stratification period. Hence, we assumed a gas pressure of N 2 in the water column of 0.79 bar (including Ar) in the following quantitative considerations: Close to the water surface, a minimal increase of oxygen partial pressure beyond 21% would result in bubble formation, while at greater depth a higher absolute pressure had to be overcome: at the given depth, partial pressure of oxygen pO 2 needed to be raised beyond local pressure p (hydrostatic + atmospheric pressure, e.g., 1.5 bar at about 5 m depth) minus partial pressure of N 2 (plus Ar) for spontaneous ebullition (Boehrer et al, ). Forming bubbles would contain an O 2 portion of

r normalO 2 = ((), p - 0.79 bar) true/ p = 1 - 0.79 bar true/ p

…”

Section: Resultsmentioning

confidence: 99%

Oxygen Ebullition From Lakes

Koschorreck

Hentschel

Boehrer

2017

Geophysical Research Letters

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The exchange of oxygen between lakes and the atmosphere is assumed to be driven by diffusion. Here we show that lakes can emit significant amounts of O2 by emerging gas bubbles—a process called ebullition. We found very high proportions of 17 ± 10% O2 (maximum 34%) in emerging gas bubbles in two shallow eutrophic reservoirs. In the studied reservoirs, O2 emission by ebullition was of similar magnitude as diffusive O2 fluxes. By reanalyzing previous studies, we show that the process is ubiquitous and probably quantitatively relevant in many places. We present evidence that O2 in bubbles originates both from photosynthetic oxygen production and hence bubble formation in the oxic water and from stripping by emerging methane bubbles. Ebullition can turn lakes undersaturated in respect to the atmosphere into a net O2 source. Neglecting O2 ebullition leads to an overestimation of lake internal respiration.

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r normalO 2 = ((), p - 0.79 bar) true/ p = 1 - 0.79 bar true/ p

…”

Section: Resultsmentioning

confidence: 99%

Oxygen Ebullition From Lakes

Koschorreck

Hentschel

Boehrer

2017

Geophysical Research Letters

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“…The measurement method used by UFZ had previously been used in highly gas charged mine pit lakes (for CO 2 see [ 16 ], for CH 4 see [ 17 ]) and was modified for the conditions of Lake Kivu by [ 13 ]. Water was sampled using gas-tight bags, which were lowered to the appropriate depth together with a small pump and an automatic pump controller.…”

Section: Methodsmentioning

confidence: 99%

No increasing risk of a limnic eruption at Lake Kivu: Intercomparison study reveals gas concentrations close to steady state

et al. 2020

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Lake Kivu, East Africa, is well known for its huge reservoir of dissolved methane (CH 4) and carbon dioxide (CO 2) in the stratified deep waters (below 250 m). The methane concentrations of up to~20 mmol/l are sufficiently high for commercial gas extraction and power production. In view of the projected extraction capacity of up to several hundred MW in the next decades, reliable and accurate gas measurement techniques are required to closely monitor the evolution of gas concentrations. For this purpose, an intercomparison campaign for dissolved gas measurements was planned and conducted in March 2018. The applied measurement techniques included on-site mass spectrometry of continuously pumped sample water, gas chromatography of in-situ filled gas bags, an in-situ membrane inlet laser spectrometer sensor and a prototype sensor for total dissolved gas pressure (TDGP). We present the results of three datasets for CH 4 , two for CO 2 and one for TDGP. The resulting methane profiles show a good agreement within a range of around 5-10% in the deep water. We also observe that TDGP measurements in the deep waters are systematically around 5 to 10% lower than TDGP computed from gas concentrations. Part of this difference may be attributed to the non-trivial conversion of concentration to partial pressure in gasrich Lake Kivu. When comparing our data to past measurements, we cannot verify the previously suggested increase in methane concentrations since 1974. We therefore conclude that the methane and carbon dioxide concentrations in Lake Kivu are currently close to a steady state.

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“…Historically, the creation of pit lakes has impacted the landscape and environment in many ways. Additionally, these lakes have the potential to contaminate groundwater resources and the wider catchment area (Boehrer et al, 2016;Davis and Ashenberg, 1989;González et al, 2018;Robles-Arena & Candela, 2010;Sarmiento, Nieto, Olías, & Cánovas, 2009;Savage et al, 2000;Søndergaard et al, 2018;Younger et al, 2002). Pit lakes have differing physical characteristics when compared to natural lakes.…”

Section: Physical Characteristicsmentioning

confidence: 99%

“…The removed overburden may be later used in the backfilling process during mine closure rehabilitation (Betournay, 2016). However, if the restoration and rehabilitation activities are not conducted on the mined-out site, the excavated voids can over time develop into pit lakes (Boehrer, Yusta, Magin, & Sánchez España, 2016;Fabri, Carneiro, & Leite, 2013;Savage, Bird, & Ashley, 2000).…”

Section: Introductionmentioning

confidence: 99%

Assessment of water quality of lakes used for recreational purposes in abandoned mines of Linden, Guyana

Williams

Oyedotun

Simmons

2019

Geology, Ecology, and Landscapes

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The open pit method is often the easiest and the most inexpensive form of mining. Bauxite mining, which commenced in 1916 in Linden, Guyana, has left many abandoned pits upon closure of mining activities; subsequently pit lakes have been formed. Globally, Acid Mine Drainage (AMD) is a common water quality problem for pit lakes. However, the pit lakes in Linden are used for recreational activities. In this study, the water quality of three lakes in Linden (NE Kara Kara, Kara Kara and Lucky Spot) were analysed for their physico-chemical characteristics. The morphological and aesthetic features were also examined. The study showed that all three lakes are acidic, with mean pH values of 3.4, 3.1 and 4.7, which are not within the allowable range for recreational waters. Mean concentrations of Al (23.06 mg/l), Fe (10.56 mg/l) and Mn (2.4 mg/l) exceeded acceptable limits; nevertheless, TDS levels measured were within the acceptable limits. In terms of aesthetic quality, NE Kara Kara and Kara Kara pit lakes were free from any form of waste and debris. For the pit lakes to be considered suitable for recreational purposes, treatment of the lakes' waters is recommended.

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Quantifying, assessing and removing the extreme gas load from meromictic Guadiana pit lake, Southwest Spain

Cited by 19 publications

References 32 publications

Oxygen Ebullition From Lakes

Oxygen Ebullition From Lakes

No increasing risk of a limnic eruption at Lake Kivu: Intercomparison study reveals gas concentrations close to steady state

Assessment of water quality of lakes used for recreational purposes in abandoned mines of Linden, Guyana

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