The Experts below are selected from a list of 324 Experts worldwide ranked by ideXlab platform
F. A. Rissberger - One of the best experts on this subject based on the ideXlab platform.
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Response of a first-order stream in Maine to short-term in-stream Acidification
Hydrology and Earth System Sciences Discussions, 2000Co-Authors: S. A. Norton, R. Wagai, T. Navratil, J. M. Kaste, F. A. RissbergerAbstract:An experimental short-term Acidification with HCl at a first-order stream in central Maine, USA was used to study processes controlling the changes in stream chemistry and to assess the ability of stream substrate to buffer pH. The streambed exerted a strong buffering capacity against pH change by ion exchange during the 6-hour Acidification. Streambed substrates had substantial cation and anion exchange capacity in the pH range of 4.1 to 6.5. The ion exchange for cations and SO42- were rapid and reversible. The speed of release of cations from stream substrates was Na1+> Ca2+ > Mg2+ > Aln+ > Be2+, perhaps relating to charge density of these cations. Ca2+ desorption dominated neutralisation of excess H+ for the first 2 hr. As the reservoir of exchangeable Ca diminished, desorption (and possibly dissolution) of Al3+ became the dominant neutralising mechanism. The exchangeable (and possibly soluble) reservoir of Al was not depleted during the 6-hour Acidification. Sulphate adsorption during the Acidification reduced the concentration of SO42- in stream water by as much as 20 ?eq L-1 (from 70 ?eq L-1). Desorption of SO42- and adsorption of base cations after the artificial Acidification resulted in a prolongation of the pH depression. The streambed had the capacity to buffer stream water chemistry significantly during an acidifying event affecting the entire upstream catchment. Keywords: stream Acidification; ion exchange; sediment; sulfate exchange; aluminium; beryllium
S. A. Norton - One of the best experts on this subject based on the ideXlab platform.
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Response of a first-order stream in Maine to short-term in-stream Acidification
Hydrology and Earth System Sciences Discussions, 2000Co-Authors: S. A. Norton, R. Wagai, T. Navratil, J. M. Kaste, F. A. RissbergerAbstract:An experimental short-term Acidification with HCl at a first-order stream in central Maine, USA was used to study processes controlling the changes in stream chemistry and to assess the ability of stream substrate to buffer pH. The streambed exerted a strong buffering capacity against pH change by ion exchange during the 6-hour Acidification. Streambed substrates had substantial cation and anion exchange capacity in the pH range of 4.1 to 6.5. The ion exchange for cations and SO42- were rapid and reversible. The speed of release of cations from stream substrates was Na1+> Ca2+ > Mg2+ > Aln+ > Be2+, perhaps relating to charge density of these cations. Ca2+ desorption dominated neutralisation of excess H+ for the first 2 hr. As the reservoir of exchangeable Ca diminished, desorption (and possibly dissolution) of Al3+ became the dominant neutralising mechanism. The exchangeable (and possibly soluble) reservoir of Al was not depleted during the 6-hour Acidification. Sulphate adsorption during the Acidification reduced the concentration of SO42- in stream water by as much as 20 ?eq L-1 (from 70 ?eq L-1). Desorption of SO42- and adsorption of base cations after the artificial Acidification resulted in a prolongation of the pH depression. The streambed had the capacity to buffer stream water chemistry significantly during an acidifying event affecting the entire upstream catchment. Keywords: stream Acidification; ion exchange; sediment; sulfate exchange; aluminium; beryllium
Josefin Sundin - One of the best experts on this subject based on the ideXlab platform.
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ocean Acidification does not impair the behaviour of coral reef fishes
Nature, 2020Co-Authors: Timothy Clark, Dominique G Roche, Ben Speersroesch, Josefin Sundin, Sandra A Binning, Fredrik Jutfelt, Graham D. RabyAbstract:The partial pressure of CO2 in the oceans has increased rapidly over the past century, driving ocean Acidification and raising concern for the stability of marine ecosystems1–3. Coral reef fishes are predicted to be especially susceptible to end-of-century ocean Acidification on the basis of several high-profile papers4,5 that have reported profound behavioural and sensory impairments—for example, complete attraction to the chemical cues of predators under conditions of ocean Acidification. Here, we comprehensively and transparently show that—in contrast to previous studies—end-of-century ocean Acidification levels have negligible effects on important behaviours of coral reef fishes, such as the avoidance of chemical cues from predators, fish activity levels and behavioural lateralization (left–right turning preference). Using data simulations, we additionally show that the large effect sizes and small within-group variances that have been reported in several previous studies are highly improbable. Together, our findings indicate that the reported effects of ocean Acidification on the behaviour of coral reef fishes are not reproducible, suggesting that behavioural perturbations will not be a major consequence for coral reef fishes in high CO2 oceans. In contrast to previous studies, analyses now show that ocean Acidification does not perturb important behaviours—such as the avoidance of chemical cues from predators—of coral reef fishes.
Stephen Widdicombe - One of the best experts on this subject based on the ideXlab platform.
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two intertidal non calcifying macroalgae palmaria palmata and saccharina latissima show complex and variable responses to short term co2 Acidification
Ices Journal of Marine Science, 2016Co-Authors: Joana Nunes, Sophie J Mccoy, Vassilis Kitidis, Ana M Queiros, Lucy Rayner, Helen S. Findlay, Frances E Hopkins, Stephen WiddicombeAbstract:Ocean Acidification, the result of increased dissolution of carbon dioxide (CO2) in seawater, is a leading subject of current research. The effects of Acidification on non-calcifying macroalgae are, however, still unclear. The current study reports two 1-month studies using two different macroalgae, the red alga Palmaria palmata (Rhodophyta) and the kelp Saccharina latissima (Phaeophyta), exposed to control (pHNBS = ∼8.04) and increased (pHNBS = ∼7.82) levels of CO2-induced seawater Acidification. The impacts of both increased Acidification and time of exposure on net primary production (NPP), respiration (R), dimethylsulphoniopropionate (DMSP) concentrations, and algal growth have been assessed. In P. palmata, although NPP significantly increased during the testing period, it significantly decreased with Acidification, whereas R showed a significant decrease with Acidification only. S. latissima significantly increased NPP with Acidification but not with time, and significantly increased R with both Acidification and time, suggesting a concomitant increase in gross primary production. The DMSP concentrations of both species remained unchanged by either Acidification or through time during the experimental period. In contrast, algal growth differed markedly between the two experiments, in that P. palmata showed very little growth throughout the experiment, while S. latissima showed substantial growth during the course of the study, with the latter showing a significant difference between the acidified and control treatments. These two experiments suggest that the study species used here were resistant to a short-term exposure to ocean Acidification, with some of the differences seen between species possibly linked to different nutrient concentrations between the experiments.
Timothy E Mcgraw - One of the best experts on this subject based on the ideXlab platform.
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Endosome Acidification and receptor trafficking: bafilomycin A1 slows receptor externalization by a mechanism involving the receptor's internalization motif.
Molecular Biology of the Cell, 1993Co-Authors: Lester S. Johnson, Kenneth Dunn, Bronislaw Pytowski, Timothy E McgrawAbstract:To examine the relationship between endosome Acidification and receptor trafficking, transferrin receptor trafficking was characterized in Chinese hamster ovary cells in which endosome acidificatio...
