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- Shumilova, Oleksandra, et al.
(författare)
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Simulating rewetting events in intermittent rivers and ephemeral streams : A global analysis of leached nutrients and organic matter
- 2019
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Ingår i: Global Change Biology. - : WILEY. - 1354-1013 .- 1365-2486. ; 25:5, s. 1591-1611
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Tidskriftsartikel (refereegranskat)abstract
- Climate change and human pressures are changing the global distribution and the extent of intermittent rivers and ephemeral streams (IRES), which comprise half of the global river network area. IRES are characterized by periods of flow cessation, during which channel substrates accumulate and undergo physico-chemical changes (preconditioning), and periods of flow resumption, when these substrates are rewetted and release pulses of dissolved nutrients and organic matter (OM). However, there are no estimates of the amounts and quality of leached substances, nor is there information on the underlying environmental constraints operating at the global scale. We experimentally simulated, under standard laboratory conditions, rewetting of leaves, riverbed sediments, and epilithic biofilms collected during the dry phase across 205 IRES from five major climate zones. We determined the amounts and qualitative characteristics of the leached nutrients and OM, and estimated their areal fluxes from riverbeds. In addition, we evaluated the variance in leachate characteristics in relation to selected environmental variables and substrate characteristics. We found that sediments, due to their large quantities within riverbeds, contribute most to the overall flux of dissolved substances during rewetting events (56%-98%), and that flux rates distinctly differ among climate zones. Dissolved organic carbon, phenolics, and nitrate contributed most to the areal fluxes. The largest amounts of leached substances were found in the continental climate zone, coinciding with the lowest potential bioavailability of the leached OM. The opposite pattern was found in the arid zone. Environmental variables expected to be modified under climate change (i.e. potential evapotranspiration, aridity, dry period duration, land use) were correlated with the amount of leached substances, with the strongest relationship found for sediments. These results show that the role of IRES should be accounted for in global biogeochemical cycles, especially because prevalence of IRES will increase due to increasing severity of drying events.
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| 2. |
- Coscieme, Luca, et al.
(författare)
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Multiple conceptualizations of nature are key to inclusivity and legitimacy in global environmental governance
- 2020
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Ingår i: Environmental Science and Policy. - : Elsevier BV. - 1462-9011 .- 1873-6416. ; 104, s. 36-42
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Tidskriftsartikel (refereegranskat)abstract
- Despite increasing scientific understanding of the global environmental crisis, we struggle to adopt the policies science suggests would be effective. One of the reasons for that is the lack of inclusive engagement and dialogue among a wide range of different actors. Furthermore, there is a lack of consideration of differences between languages, worldviews and cultures. In this paper, we propose that engagement across the science-policy interface can be strengthened by being mindful of the breadth and depth of the diverse human-nature relations found around the globe. By examining diverse conceptualizations of nature in more than 60 languages, we identify three clusters: inclusive conceptualizations where humans are viewed as an integral component of nature; non-inclusive conceptualizations where humans are separate from nature; and deifying conceptualizations where nature is understood and experienced within a spiritual dimension. Considering and respecting this rich repertoire of ways of describing, thinking about and relating to nature can help us communicate in ways that resonate across cultures and worldviews. This repertoire also provides a resource we can draw on when defining policies and sustainability scenarios for the future, offering opportunities for finding solutions to global environmental challenges.
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