@misc{PawlakNoetzelDragoetal.2022, author = {Pawlak, Julia and Noetzel, Dominique Christian and Drago, Claudia and Weithoff, Guntram}, title = {Assessing the toxicity of polystyrene beads and silica particles on the microconsumer Brachionus calyciflorus at different timescales}, series = {Zweitver{\"o}ffentlichungen der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, journal = {Zweitver{\"o}ffentlichungen der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, number = {1277}, issn = {1866-8372}, doi = {10.25932/publishup-56996}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-569967}, pages = {1 -- 11}, year = {2022}, abstract = {Environmental pollution by microplastics has become a severe problem in terrestrial and aquatic ecosystems and, according to actual prognoses, problems will further increase in the future. Therefore, assessing and quantifying the risk for the biota is crucial. Standardized short-term toxicological procedures as well as methods quantifying potential toxic effects over the whole life span of an animal are required. We studied the effect of the microplastic polystyrene on the survival and reproduction of a common freshwater invertebrate, the rotifer Brachionus calyciflorus, at different timescales. We used pristine polystyrene spheres of 1, 3, and 6 µm diameter and fed them to the animals together with food algae in different ratios ranging from 0 to 50\% nonfood particles. As a particle control, we used silica to distinguish between a pure particle effect and a plastic effect. After 24 h, no toxic effect was found, neither with polystyrene nor with silica. After 96 h, a toxic effect was detectable for both particle types. The size of the particles played a negligible role. Studying the long-term effect by using life table experiments, we found a reduced reproduction when the animals were fed with 3 µm spheres together with similar-sized food algae. We conclude that the fitness reduction is mainly driven by the dilution of food by the nonfood particles rather than by a direct toxic effect.}, language = {en} } @article{PawlakNoetzelDragoetal.2022, author = {Pawlak, Julia and Noetzel, Dominique Christian and Drago, Claudia and Weithoff, Guntram}, title = {Assessing the toxicity of polystyrene beads and silica particles on the microconsumer Brachionus calyciflorus at different timescales}, series = {Frontiers in Environmental Science}, journal = {Frontiers in Environmental Science}, publisher = {Frontiers}, address = {Lausanne, Schweiz}, issn = {2296-665X}, doi = {10.3389/fenvs.2022.955425}, pages = {1 -- 11}, year = {2022}, abstract = {Environmental pollution by microplastics has become a severe problem in terrestrial and aquatic ecosystems and, according to actual prognoses, problems will further increase in the future. Therefore, assessing and quantifying the risk for the biota is crucial. Standardized short-term toxicological procedures as well as methods quantifying potential toxic effects over the whole life span of an animal are required. We studied the effect of the microplastic polystyrene on the survival and reproduction of a common freshwater invertebrate, the rotifer Brachionus calyciflorus, at different timescales. We used pristine polystyrene spheres of 1, 3, and 6 µm diameter and fed them to the animals together with food algae in different ratios ranging from 0 to 50\% nonfood particles. As a particle control, we used silica to distinguish between a pure particle effect and a plastic effect. After 24 h, no toxic effect was found, neither with polystyrene nor with silica. After 96 h, a toxic effect was detectable for both particle types. The size of the particles played a negligible role. Studying the long-term effect by using life table experiments, we found a reduced reproduction when the animals were fed with 3 µm spheres together with similar-sized food algae. We conclude that the fitness reduction is mainly driven by the dilution of food by the nonfood particles rather than by a direct toxic effect.}, language = {en} } @article{BorckPflueger2019, author = {Borck, Rainald and Pfl{\"u}ger, Michael}, title = {Green cities? Urbanization, trade, and the environment}, series = {Journal of regional science}, volume = {59}, journal = {Journal of regional science}, number = {4}, publisher = {Wiley}, address = {Hoboken}, issn = {0022-4146}, doi = {10.1111/jors.12423}, pages = {743 -- 766}, year = {2019}, abstract = {Is urbanization good for the environment? This paper establishes a simple core-periphery model with monocentric cities, which comprises key forces that shape the structure and interrelation of cities to study the impact of the urban evolution on the environment. We focus on global warming and the potential of unfettered market forces to economize on emissions. The model parameters are chosen to match the dichotomy between average "large" and "small" cities in the urban geography of the United States, and the sectoral greenhouse gas emissions recorded for the United States. Based on numerical analyzes we find that a forced switch to a system with equally sized cities reduces total emissions. Second, any city driver which pronounces the asymmetry between the core and the periphery drives up emissions in the total city system, too, and the endogenous adjustment of the urban system accounts for the bulk of the change in emissions. Third, none of the city drivers gives rise to an urban environmental Kuznets curve according to our numerical simulations. Finally, the welfare-maximizing allocation tends to involve dispersion of cities and the more so the higher is the marginal damage from pollution.}, language = {en} }