Effect of weir impoundments on methane dynamics in a river

Bednařík, Adam; Blaser, Martin; Matoušů, Anna; Hekera, Petr; Rulı́k, Martin

doi:10.1016/j.scitotenv.2017.01.163

Cited by 22 publications

(18 citation statements)

References 74 publications

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“…Measuring protocols for PMP differ among studies presented in the literature, for example, incubation durations range from 24 hr (Crawford et al, ) to 4–6 weeks (this study; Bednařík et al, ), distilled water was added to incubation vials in some studies (Bednařík et al, ; Mach et al, ) and in others not (this study; Sanders et al, ; Wilkinson, Bodmer, et al, ). Despite these differences, our PMP rates were within the range reported by Bednařík et al () for a second‐order tributary of the Danube and Crawford et al () for a groundwater‐dominated headwater stream. We measured the same order of magnitude as Sanders et al () for an agricultural river, but with a very high variability (indicated by standard deviations; Table S1) at the depths of 1 and 5 cm below the sediment‐water interface (Figure S5a).…”

Section: Discussionmentioning

confidence: 89%

“…There are several studies in streams where PMO was investigated (e.g., Bednařík et al, ; Sanders et al, ; Shelley et al, ). Shelley et al () demonstrated concentration dependent PMO at low CH 4 concentration; this highlighted the importance of initial CH 4 spiking concentration in incubations, and this concentration dependency also differed among sediment types.…”

Section: Discussionmentioning

confidence: 99%

“…Methane production in sediments has been quantified by measuring rates of potential methane production (from here on referred as PMP) under optimal (i.e., anaerobic) conditions in laboratory incubations (Wilkinson et al, ; Bednařík et al, ; Crawford et al, ; Wilkinson, Bodmer, et al, ). In contrast to atmospheric emission rates, which exhibit strong temporal variation at timescales of minutes to days (Campeau & Del Giorgio, ; McGinnis et al, ), sediment PMP (controlled by slowly‐varying sediment temperature) has been demonstrated to be equivalent to highly dynamic methane ebullition from river impoundments over annual cycles (Wilkinson et al, ; Wilkinson et al, ).…”

Section: Introductionmentioning

confidence: 99%

“…It is unclear if such relationships exist in small streams, where the hydrodynamic conditions controlling sediment transport and accumulation are very different to those in river impoundments. In small streams, the rate of potential aerobic methane oxidation (from here on referred as PMO) may play a more important role in the sediment methane budget than in the strictly anaerobic sediments of river impoundments (e.g., Bednařík et al, ; Shelley et al, ; Shelley et al, ). The investigation of drivers of PMP and PMO spatial variability at specific depth layers is facilitated by laboratory sediment incubations, which additionally standardize their strong temperature‐dependence (Aben et al, ; Yvon‐Durocher et al, ).…”

Section: Introductionmentioning

confidence: 99%

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Sediment Properties Drive Spatial Variability of Potential Methane Production and Oxidation in Small Streams

2020

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Emissions of the potent greenhouse gas methane (CH 4 ) from streams and rivers are a significant component of global freshwater methane emissions. The distribution of CH 4 production and oxidation within stream sections and in vertical sediment profiles is not well understood, and the environmental controls on CH 4 production and emission in such systems create a significant challenge for assessing larger-scale dynamics. Here we investigate factors driving the spatial variability of sediment potential methane production (PMP) and potential methane oxidation (PMO) in a temperate stream network in Germany. PMP was highly variable, ranging from 5 × 10 −4 to 28.58 μg CH 4 gDW −1 d −1 and PMO ranged from 0.43 μg CH 4 gDW −1 d −1 to 14.41 μg CH 4 gDW −1 d −1 . Important drivers of spatial variability of PMP and PMO in the sediments of the stream main-stem were related to fine sediment fraction and organic carbon content. At smaller spatial scale, that is, in a sub-catchment stream section, the drivers were more complex and included sediment nitrogen and organic carbon content, as well as porewater dissolved organic carbon, dissolved organic matter quality, and metal concentrations. As with reservoirs and impounded rivers, fine sediment deposition and organic carbon content were found to be key controls on the spatial variability of CH 4 production and oxidation. These findings enhance our understanding of CH 4 dynamics, improve the potential for identifying CH 4 production hotspots in small streams, and provide a potential means for upscaling emission rates in larger-scale assessments.Plain Language Summary Globally, streams and rivers emit a significant amount of the highly potent greenhouse gas methane. The methane emitted from streams is mainly produced in sediments. The distribution of production and consumption in stream sections and sediment profiles is not well understood, which creates a significant challenge for estimating, for example, regional methane emissions from streams and rivers. We investigated possible factors controlling the variability from site to site and different depths of methane production and consumption in sediments of a stream network in south-west Germany. Sediment properties, the amount of fine sediment and organic carbon content, were key drivers of this variability in the main stream. In a smaller side arm of the main stream, the drivers were more complex, including nitrogen and organic carbon content of the sediment, but also porewater dissolved organic carbon, dissolved organic matter quality, and metals. As for reservoirs and dammed rivers, the accumulation of fine sediments and organic carbon content was found to be key controls of sediment methane production and consumption. These findings enhance our understanding of methane dynamics, improve the potential for identifying methane production hotspots in small streams, and provide a potential means for upscaling emission rates in larger-scale assessments.

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Section: Discussionmentioning

confidence: 89%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Sediment Properties Drive Spatial Variability of Potential Methane Production and Oxidation in Small Streams

2020

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“…The idea that low-latitude water bodies are fundamentally unpredictable or aseasonal, as well as Hutchinson and Loffler's (1956) approach of classifying lakes without morphometric information critical to understanding lake stability (Boehrer and Schultze, 2008), has been criticized repeatedly over subsequent decades as additional tropical lake studies have been published (Lewis, 1983(Lewis, , 2000(Lewis, , 1973(Lewis, , 1996. And yet, the original misleading classification diagram continues to be faithfully reproduced in contemporary limnology text books (Bengtsson et al, 2012;Wetzel, 2001). Since much of the water quality challenges associated with damming develop from the thermal and/or chemical stratification of reservoirs, we take a critical look at the issue of whether low-latitude reservoirs are likely to stratify predictably for long periods.…”

Section: Stratification In the Tropicsmentioning

confidence: 99%

Stratification behavior of tropical reservoirs - how relevant and how much emphasis does the issue deserve?

Winton¹

2019

Preprint

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The impact of large dams is a popular topic in environmental science, but the importance of altered water quality as a driver of ecological impacts is often missing from such discussions. This is partly because information on the relationship between dams and water quality is relatively sparse and fragmentary, especially for low-latitude developing countries where dam building is now concentrated. In this paper, we review and synthesize information on the effects of damming on water quality with a special focus on low latitudes. We find that two ultimate physical processes drive most water quality changes: the trapping of sediments and nutrients, and thermal stratification in reservoirs. Since stratification emerges as an important driver and there is ambiguity in the literature regarding the stratification behavior of water bodies in the tropics, we synthesize data and literature on the 54 largest low-latitude reservoirs to assess their mixing behavior using three classification schemes. Direct observations from literature as well as classifications based on climate and/or morphometry suggest that most, if not all, low-latitude reservoirs will stratify on at least a seasonal basis. This finding suggests that low-latitude dams have the potential to discharge cooler, anoxic deep water, which can degrade downstream ecosystems by altering thermal regimes or causing hypoxic stress. Many of these reservoirs are also capable of efficient trapping of sediments and bed load, transforming or destroying downstream ecosystems, such as floodplains and deltas. Water quality impacts imposed by stratification and sediment trapping can be mitigated through a variety of approaches, but implementation often meets physical or financial constraints. The impending construction of thousands of planned low-latitude dams will alter water quality throughout tropical and subtropical rivers.These changes and associated environmental impacts need to be better understood by better baseline data and more sophisticated predictors of reservoir stratification behavior. Improved environmental impact assessments and dam designs have the potential to mitigate both existing and future potential impacts.

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