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- Buffam, Ishi, et al.
(författare)
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Environmental drivers of seasonal variation in green roof runoff water quality
- 2016
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Ingår i: Ecological Engineering. - : Elsevier. - 0925-8574 .- 1872-6992. ; 91, s. 506-514
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Tidskriftsartikel (refereegranskat)abstract
- Green (vegetated) roofs provide many beneficial environmental services but can also pose a disservice by leaching nutrients and metals, via storm water runoff, to downstream aquatic ecosystems. Current estimates of water quality impacts rely on limited samples (snapshots in time) and may not accurately reflect the true influence of green roof ecosystems, which likely vary temporally as do natural ecosystems. Using a 46 m(2) green roof in Cincinnati, OH, we analyzed runoff from >80 events over two years for pH, conductivity, and concentrations of dissolved nutrients, base cations, and metals. We related the variation in water chemistry to environmental variables including air temperature, storm event magnitude, and estimated antecedent moisture. We observed strong seasonal patterns in bioactive elements, with carbon, nitrogen, phosphorus, and base cation concentrations highest in the summer, and positively correlated with temperature. This suggests temperature-mediated processes such as microbial mineralization of organic matter, desorption or weathering, rather than plant uptake or hydrologic variation among storms, are the major controlling mechanisms for runoff water quality in this newly constructed green roof. The large temporal variation in green roof effluent water quality supports the need for long-term studies to characterize the complexity of these engineered ecosystems and their responsiveness to environmental variation. (C) 2016 Elsevier B.V. All rights reserved.
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| 2. |
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| 3. |
- Durtsche, Richard D., et al.
(författare)
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Thermal conditions during embryogenesis influence metabolic rates of juvenile brown trout Salmo trutta
- 2021
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Ingår i: Ecosphere. - : John Wiley & Sons. - 2150-8925 .- 2150-8925. ; 12:2, s. 1-14
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Tidskriftsartikel (refereegranskat)abstract
- The projected climate change and increase in thermal conditions in northern latitudes over the next 60 yr has the potential to alter the metabolic scope and potential fitness of aquatic ectotherms. Here, we experimentally tested if elevated egg incubation temperature affected metabolic scope in juvenile brown trout (Salmo trutta) as a phenotypically plastic response. Cohorts of brown trout from anadromous and resident crosses were raised through embryogenesis in either natural river temperatures (cold) or elevated (+3 degrees C, warm) temperatures until they could feed exogenously. The standard metabolic rate (SMR), maximum metabolic rate (MMR), and aerobic scope (AS = MMR - SMR) of juveniles from four anadromous-resident crosses and from both incubation temperatures were tested at 13 degrees C. We found that metabolic measures (SMR, MMR, AS) were lower in warm than cold-incubated fish. There was no difference in the metabolic rates of fish from different anadromous-resident crosses. The results of this experiment are consistent with the countergradient variation hypothesis (CGV) in which phenotypic variation, in this case variation in metabolic rates, is inversely related to thermal conditions, originally proposed in relation to altitudinal or latitudinal gradients. While previous studies have related CGV to genetic differences between populations, our study shows that thermal differences encountered at the embryonic stage can produce a phenotypic pattern consistent with CGV. It is difficult to predict the consequences of these metabolic changes in a future warmer climate, as lower metabolic rates indicate that brown trout will probably expend less energy, but a reduced aerobic scope may counteract this affect, limiting their ability as a top predator and in escaping predators. Our results suggest that there are mechanisms used to adjust to elevated water temperature that can be initiated during embryogenesis. Given that there were no differences among crosses, it is likely that temperature-induced differences are the result of plastic responses.
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| 4. |
- Piccolo, John, 1964-, et al.
(författare)
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Future rivers, dams and ecocentrism.
- 2019
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Ingår i: The Ecological Citizen. - 2515-1967. ; 2:2, s. 173-177
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Tidskriftsartikel (refereegranskat)abstract
- In this article the authors look at the subject of ecocentrism and future rivers, focusing mainly on the effects of hydroelectric production. Although rivers also have been dammed for irrigation and flood control in addition to hydroelectricity, the production of ‘carbon-free’ energy has recently been touted as a major solution to climate change. The trade-off between clean energy and the negative impacts of hydropower offers much food for thought for ecocentric theory – how much biodiversity loss are we justified in allowing now, for example, to avert complete ecosystem collapse in the future if we continue to rely on fossil fuel? The authors intend this article to be a starting point for discussion of rivers and ecocentrism in general, and they conclude with some specific suggestions regarding rivers and hydropower.
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