Abiotic influences on dissolved oxygen in a riverine environment

He, Jianxun; Chu, Angus; Ryan, M. Cathryn; Valeo, Caterina; Zaitlin, Beryl

doi:10.1016/j.ecoleng.2011.06.022

Cited by 51 publications

(39 citation statements)

References 20 publications

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“…During summer heatwave periods in particular, solar energy plays a key role in influencing stream energy heat budget, and consequently stream water temperature (Johnson, 2004;Leach and Moore, 2010;Groom et al, 2011). Hence shading through riparian vegetation, primarily in small to medium sized and slowly flowing lowland rivers, is often most relevant to avoid excessive heating in order to mitigate adverse effects on the ecosystem (Ghermandi et al, 2009;He et al, 2011;Holzapfel et al, 2013).…”

Section: Introductionmentioning

confidence: 99%

The influence of riparian vegetation shading on water temperature during low flow conditions in a medium sized river

Kalny

Laaha

Melcher

et al. 2017

Knowl. Manag. Aquat. Ecosyst.

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-Stream water temperature limits the growth and survival of aquatic organisms; whereby riparian shading plays a key role in inhibiting river warming. This study explains the effects of riparian shading on summer water temperatures at a pre-alpine Austrian river, during heatwave and nonheatwave periods at low flow conditions. A vegetation-shading index was introduced for the quantification of riparian vegetation effects on water temperature. For maximum water temperatures, a downstream warming of 3.9°C was observed in unshaded areas, followed by a downstream cooling of 3.5°C in shaded reaches. Water temperature directly responded to air temperature and cloudiness. For an air temperature change of 2°C we modelled a water temperature change of 1.3°C for unshaded reaches, but lower changes for intensively shaded reaches. Similar daily variations at shaded reaches were up to 4°C lower than unshaded ones. This study gives clear evidence that for a medium-sized prealpine river, restoration practices should consider that discontinuity of riparian vegetation should be less than 6000 m; with more than 40% dense vegetation in order to minimize water temperature increases due to unshaded conditions. Keywords: riparian vegetation / vegetation-shading index / water temperature / river vegetation management / restorationRésumé -L'influence de la végétation rivulaire sur la température de l'eau pendant les conditions de faible débit dans une rivière de taille moyenne. La température de l'eau d'une rivière limite la croissance et la survie des organismes aquatiques ; de ce fait l'ombrage rivulaire joue un rôle clé dans la limitation du réchauffement des rivières. Cette étude analyse les effets de l'ombrage rivulaire sur les températures estivales de l'eau dans une rivière autrichienne préalpine, pendant les périodes de canicule et de non-canicule à faible débit. Un indice d'ombrage de la végétation a été introduit pour la quantification des effets de la végétation rivulaire sur la température de l'eau. Pour les températures maximales de l'eau, un réchauffement en aval de 3,9°C a été observé dans les zones non ombragées, suivi d'un refroidissement en aval de 3,5°C dans les zones ombragées. La température de l'eau a répondu directement à la température de l'air et à la nébulosité. Pour un changement de température de l'air de 2°C, nous avons modélisé un changement de température de l'eau de 1,3°C pour les zones non ombragées, mais des changements plus faibles pour les niveaux intensivement ombragés. Des variations quotidiennes semblables dans des zones ombragées étaient jusqu'à 4°C inférieures à celles non ombragées. Cette étude montre clairement que pour une rivière préalpine de taille moyenne, les pratiques de restauration devraient considérer que la discontinuité de la végétation riveraine doit être

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Section: Introductionmentioning

confidence: 99%

The influence of riparian vegetation shading on water temperature during low flow conditions in a medium sized river

Kalny

Laaha

Melcher

et al. 2017

Knowl. Manag. Aquat. Ecosyst.

View full text Add to dashboard Cite

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“…An advantage of using these factors is that they are routinely collected by the City of Calgary, and thus a large data set is available. Also, their use in previous studies has shown that they are good predictors of daily DO concentration in this river basin (He et al, 2011;Khan et al, 2013;Khan and Valeo, 2015). The following sections outline the background of fuzzy numbers and existing probability-possibility transformations.…”

Section: Objectivesmentioning

confidence: 99%

“…In general, these studies have demonstrated that there is a need and demand for less complex DO models, have led to an increase in the popularity of data-driven models (Antanasijević et al, 2014), and shown that the performance of these types of models is suitable. Recent research into predicting DO concentration in the Bow River in Calgary using abiotic factors (these are non-living, physical and chemical attributes) as inputs have shown promising results (He et al, 2011;Khan et al, 2013;Khan and Valeo, 2015). The advantage of using readily available data (i.e.…”

Section: Fuzzy Numbers and Data-driven Modellingmentioning

confidence: 99%

“…flood events) were demonstrative of the complexity in understanding river processes in an urban area, and that consideration of various inputs, outputs and their interaction is important to fully understand the system. He et al (2011) found that seasonal variations in DO in the Bow River could be explained by a combination of abiotic factors (such as climatic and hydrometric conditions), as well as by biotic factors. The study found that while photosynthesis and respiration of biota are the main drivers of DO fluctuation, the role of nutrients was ambiguous.…”

Section: Introductionmentioning

confidence: 99%

“…DO is an indicator of overall health of the aquatic ecosystem (Dorfman and Jacoby, 1972;Hall, 1984; Canadian Council of Ministers of the Environment, 1999; Kannel et al, 2007;Valeo, 2014a, 2015), and low DOwhich can be caused by a number of different factors (Pogue and Anderson, 1995;Hauer and Hill, 2007;He et al, 2011;Wen et al, 2013) -can impact various organisms in the water body. While the impact of long-term effects of low DO are largely unknown, acute events can have devastating effects on aquatic ecosystems (Adams et al, 2013).…”

Section: Introductionmentioning

confidence: 99%

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Dissolved oxygen prediction using a possibility theory based fuzzy neural network

Khan

Valeo

2016

Hydrol. Earth Syst. Sci.

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Abstract.A new fuzzy neural network method to predict minimum dissolved oxygen (DO) concentration in a highly urbanised riverine environment (in Calgary, Canada) is proposed. The method uses abiotic factors (non-living, physical and chemical attributes) as inputs to the model, since the physical mechanisms governing DO in the river are largely unknown. A new two-step method to construct fuzzy numbers using observations is proposed. Then an existing fuzzy neural network is modified to account for fuzzy number inputs and also uses possibility theory based intervals to train the network. Results demonstrate that the method is particularly well suited to predicting low DO events in the Bow River. Model performance is compared with a fuzzy neural network with crisp inputs, as well as with a traditional neural network. Model output and a defuzzification technique are used to estimate the risk of low DO so that water resource managers can implement strategies to prevent the occurrence of low DO.

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Demography and movement patterns of a freshwater ciliate: The influence of oxygen availability

Brans,

Manzi,

Jacob

et al. 2024

Ecology and Evolution

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In freshwater habitats, aerobic animals and microorganisms can react to oxygen deprivation by a series of behavioural and physiological changes, either as a direct consequence of hindered performance or as adaptive responses towards hypoxic conditions. Since oxygen availability can vary throughout the water column, different strategies exist to avoid hypoxia, including that of active ‘flight’ from low‐oxygen sites. Alternatively, some organisms may invest in slower movement, saving energy until conditions return to more favourable levels, which may be described as a ‘sit‐and‐wait’ strategy. Here, we aimed to determine which, if any, of these strategies could be used by the freshwater ciliate Tetrahymena thermophila when faced with decreasing levels of oxygen availability in the culture medium. We manipulated oxygen flux into clonal cultures of six strains (i.e. genotypes) and followed their growth kinetics for several weeks using automated image analysis, allowing to precisely quantify changes in density, morphology and movement patterns. Oxygen effects on demography and morphology were comparable across strains: reducing oxygen flux decreased the growth rate and maximal density of experimental cultures, while greatly expanding the duration of their stationary phase. Cells sampled during their exponential growth phase were larger and had a more elongated shape under hypoxic conditions, likely mirroring a shift in resource investment towards individual development rather than frequent divisions. In addition to these general patterns, we found evidence for intraspecific variability in movement responses to oxygen limitation. Some strains showed a reduction in swimming speed, potentially associated with a ‘sit‐and‐wait’ strategy; however, the frequent alteration of movement paths towards more linear trajectories also suggests the existence of an inducible ‘flight response’ in this species. Considering the inherent costs of turns associated with non‐linear movement, such a strategy may allow ciliates to escape suboptimal environments at a low energetic cost.

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Abiotic influences on dissolved oxygen in a riverine environment

Cited by 51 publications

References 20 publications

The influence of riparian vegetation shading on water temperature during low flow conditions in a medium sized river

The influence of riparian vegetation shading on water temperature during low flow conditions in a medium sized river

Dissolved oxygen prediction using a possibility theory based fuzzy neural network

Demography and movement patterns of a freshwater ciliate: The influence of oxygen availability

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