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317. Stress in ecological systems

Author

Parker, E. D., Forbes, V. E., Nielsen, S. L., Ritter, C., Barata, C., Baird, D. J., Admiraal, W., Levin, L., Loeschke, V., Lyytikäinen-Saarenmaa, P., Jensen, Henning Høgh, Calow, P., Ripley, B. J., Parker, E. D., Forbes, V. E., Nielsen, S. L., Ritter, C., Barata, C., Baird, D. J., Admiraal, W., Levin, L., Loeschke, V., Lyytikäinen-Saarenmaa, P., Jensen, Henning Høgh, Calow, P., and Ripley, B. J.

Published
1999

321. Variability in Zinc Tolerance, Measured as Incorporation of Radio-Labeled Carbon Dioxide and Thymidine, in Periphyton Communities Sampled from 15 European River Stretches

Author

Blanck, H., primary, Admiraal, W., additional, Cleven, R. F. M. J., additional, Guasch, H., additional, van den Hoop, M. A. G. T., additional, Ivorra, N., additional, Nyström, B., additional, Paulsson, M., additional, Petterson, R. P., additional, Sabater, S., additional, and Tubbing, G. M. J., additional

Published
2003
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332. Stress in Ecological Systems

Author

Parker, E. D., primary, Forbes, V. E., additional, Nielsen, S. L., additional, Ritter, C., additional, Barata, C., additional, Baird, D. J., additional, Admiraal, W., additional, Levin, L., additional, Loeschke, V., additional, Lyytikainen-Saarenmaa, P., additional, Hogh-Jensen, H., additional, Calow, P., additional, and Ripley, B. J., additional

Published
1999
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337. Invloed van EDTA op speciatie en toxiciteit van koper in Dutch Standard Water: een voltammetrisch, ecotoxicologisch en modelmatig onderzoek

Author

Meent D van de, Cleven RFMJ, Tubbing GMJ, Esseveld FG van, Wolfs PM, Admiraal W, Meent D van de, Cleven RFMJ, Tubbing GMJ, Esseveld FG van, Wolfs PM, and Admiraal W

Abstract

RIVM rapport:As a result of the increasing emission of complexformers like EDTA (ethylenediaminetetra-acetic acid) or NTA (nitrilotri-acetec acid), the speciation characteristics of metals will change. In this study the effect of EDTA (in a synthetic medium) on the speciation and biological activity of copper has been studied. The experimental set-up was three-fold: -the determination of the copper speciation electrochemically (Differential Pulse Anodic Stripping Voltammetry) in combination with UV-destruction and ion-exchange (Chelex), -the determination of the biological activity of the algae Selenastrum capricornutum (photosynthesis) and with the Microtox-test (light inhibition), -modelling of the speciation pattern. The calculated "not-EDTA" bound copper gives a better description of the photosynthetic activity than total copper concentrations, but it can not be used quantitatively. The experimentally determined "chelex- bound" copper fraction seems to be a good descriptor of the observed changes in the photosynthetic activity of S. capricornutum. More research to the validity of this relation for other water types is desired to enable the possibility to generalize and to improve the extrapolation methods.

Published
1993

338. Plankton in de Rijn

Author

Ruyter van Steveninck, E.D. de, Tubbing, G.M.J., Admiraal, W., Ruyter van Steveninck, E.D. de, Tubbing, G.M.J., and Admiraal, W.

Published
1992

345. Cold-induced activity of brown adipose tissue in young lean men of South-Asian and European origin.

Author

Admiraal, W., Verberne, H., Karamat, F., Soeters, M., Hoekstra, J., and Holleman, F.

Abstract

Aims/hypothesis: South Asians have a disproportionately high risk of developing abdominal obesity, insulin resistance and type 2 diabetes. Brown adipose tissue (BAT) has been identified as a possible target to fight obesity and protect against metabolic disturbance. We explored whether lower BAT activity in South Asians compared with Europids may contribute to the high risk of metabolic disturbance. Methods: We studied 20 healthy men (ten Europids/ten South Asians, BMI 19-25 kg/m, age 18-32 years). Following 2 h of cold exposure (16-18°C) after an overnight fast, F-fluorodeoxyglucose (F-FDG) positron-emission tomography-computed tomography (CT) and I-metaiodobenzylguanidine (I-MIBG) single-photon emission computed tomography-CT were performed to visualise metabolic BAT activity and sympathetic stimulation of BAT. Metabolic BAT activity was defined as maximal standardised uptake value (SUV) of F-FDG, and sympathetic stimulation of BAT as semiquantitative uptake value (SQUV) of I-MIBG. We performed hyperinsulinaemic-euglycaemic clamps to assess insulin sensitivity. Spearman's correlations for SUV of F-FDG and both SQUV of I-MIBG and insulin sensitivity were determined. Results: The median (interquartile range) SUV of F-FDG in South Asians (7.5 [2.2-10.6] g/ml) was not different from the median SUV obtained in Europids (4.5 [2.2-8.4] g/ml; p = 0.59). There was no correlation between BAT activity and insulin sensitivity. Correlations between SQUV of I-MIBG and SUV of F-FDG were positive, both in the total population ( ρ = 0.80, p < 0.001) and after stratification by ethnicity (Europids, ρ = 0.65, p = 0.04; South Asians, ρ = 0.83, p = 0.01). Conclusions/interpretation: This is the first study to prospectively investigate ethnic differences in metabolic BAT activity during cold exposure. We did not find differences in BAT activity between South Asians and Europids. Therefore, it seems unlikely that BAT plays an important role in the development of unfavourable metabolic profiles in South Asians. [ABSTRACT FROM AUTHOR]

Published
2013
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346. Effects of copper on invertebrate–sediment interactions.

Author

Hunting, E.R., Mulder, C., Kraak, M.H.S., Breure, A.M., and Admiraal, W.

Subjects
COPPER poisoning, SEDIMENTS, INVERTEBRATES, BIODIVERSITY, ECOSYSTEMS, BIOTURBATION, BIODEGRADATION
Abstract

Abstract: Toxicants potentially decouple links between biodiversity and ecosystem processes. This study aimed to evaluate how toxicants affect invertebrate bioturbation and decomposition. Effects of copper on functionally distinct macrofaunal species (Asellus aquaticus and Tubifex spp.), decomposition (release of dissolved organic carbon, DOC) and Average Metabolic Response (AMR) and Community Metabolic Diversity (CMD) of bacteria were determined in 5-day microcosm experiments. Bioturbation was assessed as sediment redox potential (Eh) profiles. Concentration–response curves of the functional parameters DOC, and the faunal mediated AMR and CMD in the presence of Tubifex spp. depended on Tubifex spp. survival, i.e. similar EC50 values for both endpoints. In contrast, functional parameters in the presence of A. aquaticus were more sensitive than survival. Sediment Eh-profiles showed that reduced decomposition was caused by reduced sediment reworking by A. aquaticus at sub-lethal copper concentrations. These observations hint at a decoupling of invertebrate community structure and ecosystem functioning upon stress. [Copyright &y& Elsevier]

Published
2013
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350. Influence of phosphorus on copper sensitivity of fluvial periphyton: the role of chemical, physiological and community-related factors.

Author

Serra, Alexandra, Guasch, H., Admiraal, W., Van der Geest, H. G., and Van Beusekom, S. A. M.

Subjects
TOXICOLOGY of water pollution, PERIPHYTON, PHOSPHORUS, EUTROPHICATION, COPPER, LAND use
Abstract

The influence of eutrophication of fluvial ecosystems (caused by increased phosphorus concentrations) on periphyton Cu sensitivity is explored from a multi-scale perspective, going from the field to the laboratory. The study design included three tiers: a field study including the characterization of land use and the ecological state of the corresponding river sections in the Fluviá River watershed, an experimental investigation performed with natural periphyton from the previously studied stream sites in indoor channels, and finally a culture study in the laboratory. Results showed that differences in copper sensitivity of natural periphyton communities followed the gradient of nutrient concentration found in the field. Results from the culture experiments demonstrated that both, P-conditions during growth and P-content in the media are important factors modulating the toxicological response of algae to Cu. The observations from this study indicate that the ecological effects of metal pollution in rivers might be obscured by eutrophication. [ABSTRACT FROM AUTHOR]

Published
2010
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