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  • 1
    Language: English
    In: Freshwater Biology, Feb, 2013, Vol.58, p.372(10)
    Description: To purchase or authenticate to the full-text of this article, please visit this link: http://onlinelibrary.wiley.com/doi/10.1111/fwb.12065/abstract Byline: JOCHEN BECKER(1)(2), CHRISTIAN ORTMANN(3), MARKUS A. WETZEL(1)(2), CAROLA WINKELMANN(2), JOCHEN H. E. KOOP(1)(2) Keywords: Gammarus spp.; glycogen; reproductive period; seasonality; triglyceride Summary 1. We assessed sex-specific seasonal changes in major energy storage compounds (triglycerides, glycogen) in Gammarus fossarum and Gammarus pulex collected from the field, with respect to their reproductive activity. 2. The dynamics of stored energy followed a seasonal pattern in both species and sexes. Moreover, over a 4-year period, these changes were independent of the year in which they were investigated. Stored energy reached a peak in late winter, but was depleted in late summer and early autumn, coinciding with the reproductive periods. 3. Triglyceride (annual mean [+ or -] SD) accounted for 79.7 [+ or -] 11.9% of the total stored energy and was responsible for the seasonal pattern. In contrast, glycogen contributed a lesser percentage (20.3 [+ or -] 11.9%). Over the study period, the amount of stored energy ranged between 0.39 and 4.08 kJ g.sub.-1 dry mass (triglyceride: 0.19-3.69 kJ g.sub.-1 dry mass; glycogen: 0.14-0.80 kJ g.sub.-1 dry mass). 4. In both species, the energy reserves of males were drastically depleted shortly before the cessation of precopulatory mate guarding in the field, thus offering a bioenergetic explanation for the reproductive period in these two widespread species. Author Affiliation: (1)Department of Animal Ecology, Federal Institute of Hydrology, Koblenz, Germany (2)Department of Biology, University Koblenz-Landau, Koblenz, Germany (3)TA Instruments, Eschborn, Germany Correspondence: (*) Jochen Becker, Department of Biology, University Koblenz-Landau, Universitatsstra[sz]e 1, 56070 Koblenz, Germany. E-mail: jochenbecker@uni-koblenz.de (Manuscript accepted 24 October 2012)
    Keywords: Glycogen ; Triglycerides ; Hydrology
    ISSN: 0046-5070
    Source: Cengage Learning, Inc.
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  • 2
    Language: English
    In: Science of the Total Environment, 01 April 2013, Vol.449, pp.199-207
    Description: Sediment contamination is one of the most pressing environmental problems in estuaries of industrialized countries and is of special interest to water managers involved in waterway maintenance dredging. In the present study, eight heavy metals (As, Pb, Cd, Cr, Cu, Ni, Hg, and Zn) and 41 organic compounds (pentachlorbenzol (PeCB), hexachlorbenzol (HCB), 7 polychlorinated biphenyls (PCBs), the hexachlorocyclohexanes α-HCH, β-HCH, γ-HCH, 6 dichlorodiphenyltrichloroethane isomers, organochlorine styrene (OCS), octachloronaphthalene (OCN), 15 polycyclic aromatic hydrocarbons (PAHs), and 6 organotin (OT) compounds) were analyzed in surface sediments at 36 sites in the Elbe estuary in 2006. Correlation analysis showed a general decrease in sediment contaminant concentrations from the stations near the port of Hamburg towards the open sea. This decrease was significant (Spearman's rank correlation, p 〈 0.05) with most pollutants. In addition, cluster analysis identified five groups of sites with different sediment contaminant patterns within the Elbe estuary. Worst case toxic risks stemming from sediment-bound organic pollutants were predicted using the Toxic Unit approach, based on estimated pore-water concentrations under equilibrium conditions and acute LC50 values for three standard test organisms of the trophic levels of fish, invertebrates, and algae. The estimated sediment toxicity was significantly higher in the inner part (river-km 630 to 660) compared with the estuarine mouth. Moreover, potential toxicity of organic pollutants estimated for invertebrates and for fish exceeded acute-based effect thresholds at 30 and 24 stations, respectively. Chronic effects for invertebrates are expected at all sites investigated. We conclude that sediment pollution and related potential toxicity in the Elbe estuary may have more influence on the benthos fauna than expected to date. ► Eight heavy metals and 41 organic compounds were measured in the Elbe estuary. ► Toxic Units were calculated for fish, invertebrates, and algae. ► Acute effects on invertebrates and fish are to be expected at 30 and 24 stations. ► Sediment pollution in the Elbe estuary probably influences the benthos fauna.
    Keywords: Toxic Units ; Water Framework Directive ; Sediment Pollution ; Macrofauna ; Fish ; Algae ; Environmental Sciences ; Biology ; Public Health
    ISSN: 0048-9697
    E-ISSN: 1879-1026
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  • 3
    Language: English
    In: Geotextiles and Geomembranes, 2011, Vol.29(4), pp.440-446
    Description: Geotextile materials find increasing use in coastal protection as an alternative material to natural stone, slag, and concrete. In this environment geotextiles, like all surfaces of technical objects immersed in seawater, are subject to accumulation of organisms on their surfaces, a process usually called biofouling. In a 2-year experiment we investigated the colonization of benthic organisms on two different geotextile materials (woven fabric and non-woven fabric) in the Elbe estuary, Germany, and compared it with the colonization on unglazed ceramic tiles as reference representing the nearest compromise to natural hard substrates. Then, non-woven fabric was colonized by significantly less species, fewer individuals, and lower biomass values than the woven fabric and the ceramic tiles (one-factor ANOVA, 〈 0.05); no such significant differences were noted between woven fabric and ceramic tiles. Over time, the numbers of species and numbers of individuals did not show significant increases between the first and the second year (Student’s -test, ≥ 0.05), while the biomass was still increasing significantly on all materials ( -test, 〈 0.05). However, biomass was almost two orders of magnitude lower on non-woven geotextiles than on woven material. Exposure to seawater and fouling organisms had no adverse effect upon the stability of the geotextiles (wide-width tensile test results; -test ≥ 0.05). Geotextile materials therefore offer a unique choice in coastal and hydraulic engineering: depending on the application, engineers can choose between a material that is easily colonized by benthic species, or one that minimizes such colonization where it is undesired.
    Keywords: Woven Fabric ; Non-Woven Fabric ; Geotextile Container ; Biofouling ; Marine Benthos ; Elbe Estuary ; Engineering ; Economics
    ISSN: 0266-1144
    E-ISSN: 1879-3584
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  • 4
    Language: German
    In: Bautechnik, December 2015, Vol.92(12), pp.860-866
    Description: Die Ingenieurwissenschaften werden zu den exakten Wissenschaften gezählt. Damit verbunden ist die Notwendigkeit der Verwendung einer präzisen Sprache und einer präzisen Fachdidaktik. Schaut man in Fachaufsätze, Lehrbücher, Normen oder Gutachten, bekommt man manchmal das Gefühl, dass es sich bei der (technischen) Sprache eher um eine babylonische Sprachenverwirrung handelt. Der folgende Bericht möchte anhand von Beispielen zeigen, dass eine einheitliche und präzise Fachdidaktik das Verstehen, das Verständnis, das Lernen und die unmissverständliche Kommunikation fördert. Remarks on technical didactics Engineering sciences are considered to be exact sciences. Thus, both the technical language as well as technical didactics should be exact or at least precise. Reading technical papers, text books, codes or reports one might get the impression that we deal with babylonian confusion rather than with a precise language. This paper is intended to show with some examples that precise technical didactics is essential for better understanding, learning and communication.
    Keywords: Fachdidaktik ; Fachbegriffe ; Kommunikation ; Fachliche ; Technical Didactics ; Technical Terms ; Technical Communication ; Baugeschichte ‐ History Of Structures ; Baumechanik ‐ Structural Mechanics ; Baustoffe ‐ Building Materials
    ISSN: 0932-8351
    E-ISSN: 1437-0999
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  • 5
    Language: English
    In: Ecological Indicators, Nov, 2013, Vol.34, p.323(9)
    Description: To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.ecolind.2013.05.008 Byline: Thomas Taupp, Markus A. Wetzel Abstract: acents Different benthic indices were applied at dumping and nearby reference areas in the Elbe estuary (Germany). acents All indices, except the W-value, were able to differentiate between dumping and reference areas and showed better index values at reference areas. acents We recommend to use species richness, Shannon diversity, AMBI, and M-AMBI to detect physical disturbances in the Elbe estuary. Author Affiliation: (a) Institute for Integrated Natural Sciences, University Koblenz-Landau, Universitatsstrasse 1, 56070 Koblenz, Germany.sup.1 (b) Department of Animal Ecology, German Federal Institute of Hydrology - BfG, Am Mainzer Tor 1, 56068 Koblenz, Germany Article History: Received 8 March 2013; Revised 10 May 2013; Accepted 14 May 2013
    Keywords: Hydrology -- Comparative Analysis ; Estuaries -- Comparative Analysis ; Quality Control -- Comparative Analysis ; Business Relocation -- Comparative Analysis
    ISSN: 1470-160X
    Source: Cengage Learning, Inc.
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  • 6
    In: Freshwater Biology, February 2013, Vol.58(2), pp.372-381
    Description: 1. We assessed sex‐specific seasonal changes in major energy storage compounds (triglycerides, glycogen) in and collected from the field, with respect to their reproductive activity. 2. The dynamics of stored energy followed a seasonal pattern in both species and sexes. Moreover, over a 4‐year period, these changes were independent of the year in which they were investigated. Stored energy reached a peak in late winter, but was depleted in late summer and early autumn, coinciding with the reproductive periods. 3. Triglyceride (annual mean ± SD) accounted for 79.7 ± 11.9% of the total stored energy and was responsible for the seasonal pattern. In contrast, glycogen contributed a lesser percentage (20.3 ± 11.9%). Over the study period, the amount of stored energy ranged between 0.39 and 4.08 kJ g dry mass (triglyceride: 0.19–3.69 kJ g dry mass; glycogen: 0.14–0.80 kJ g dry mass). 4. In both species, the energy reserves of males were drastically depleted shortly before the cessation of precopulatory mate guarding in the field, thus offering a bioenergetic explanation for the reproductive period in these two widespread species.
    Keywords: Spp. ; Glycogen ; Reproductive Period ; Seasonality ; Triglyceride
    ISSN: 0046-5070
    E-ISSN: 1365-2427
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  • 7
    Language: English
    In: Estuarine, Coastal and Shelf Science, July 5, 2014, Vol.148, p.27(9)
    Description: To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.ecss.2014.06.008 Byline: Thomas Taupp, Markus A. Wetzel Abstract: The Venice System is one of the best-known and most applied systems to classify waters with respect to salinity. It has often been subject to criticism because the criteria used to derive zone boundaries were not made explicit. Consequently, an alternative multivariate PCA method that aimed at identifying salinity zones by means of the salinity ranges preferred by species was introduced by Bulger et al. (1993). We tested the applicability of both methods using salinity and benthic macroinvertebrate data for the poikilohaline Elbe Estuary (Germany) from 1997 to 2012. This was done by comparing the resultant salinity zone limits from the two approaches with boundaries where significant community changes were found by means of cluster analysis. Only the Venice System polyhaline and limnetic zone boundaries, and the PCA method outer estuary zone limit, showed good agreement with the benthic community pattern. None of the other Venice System or PCA method zone limits reflected the benthic community patterns. Our findings suggest that zone limits can only be well determined from mean salinity at the inner and outer end of the estuary, where the variation of salinity is relatively low. In contrast, in the middle of the estuary variation in salinity is the better predictor of zone boundaries. Thus, application of the Venice System or the PCA method in poikilohaline estuaries, such as the Elbe, is not meaningful and their use should be limited to homoiohaline systems. For poikilohaline systems, we found cluster analysis to be a better tool to identify salinity-zone boundaries. Author Affiliation: (a) Institute for Integrated Natural Sciences, University Koblenz-Landau, Universitatsstrasse 1, 56070 Koblenz, Germany (b) Department of Animal Ecology, German Federal Institute of Hydrology - BfG, Am Mainzer Tor 1, 56068 Koblenz, Germany Article History: Received 30 April 2014; Accepted 14 June 2014
    Keywords: Hydrology -- Analysis ; Estuaries -- Analysis ; Salinity -- Analysis
    ISSN: 0272-7714
    Source: Cengage Learning, Inc.
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  • 8
    Language: English
    In: Comparative Biochemistry and Physiology, Part A, January 2016, Vol.191, pp.119-126
    Description: The Ponto-Caspian amphipod is one of the most successful invaders in Central European rivers. Contrary to studies on its ecology, ecophysiological studies comparing the species' physiological traits are scarce. In this context, in particular the metabolic activity of the invasive species has rarely been considered and, moreover, the few existing studies on this species report strongly deviating results. The purpose of this study was to assess the metabolic activity and behavior of and other common European amphipod species ( , ) in relation to temperatures covering the thermal regime of the invaded habitats. Based on direct calorimetric measurements of metabolic heat dissipation at three temperature levels (5 °C, 15 °C and 25 °C), we found the routine metabolic rate of to be significantly lower than that of the other studied gammarid species at the medium temperature level. The estimated resting metabolic rate indicated a similar trend. At 5 °C and 25 °C, both routine and resting metabolic rate did not differ between species. Compared to and , exhibited lower locomotor activity at the low and medium temperatures (5 °C and 15 °C). In contrast, its locomotor activity increased at the high experimental temperature (25 °C). and were apparently more active than at all studied temperatures. We conclude that has both physiological and behavioral adaptations that lead to a reduction in metabolic energy expenditure, which is assumed to be beneficial and might contribute to its invasive success.
    Keywords: Dikerogammarus Villosus ; Gammarus Fossarum ; Gammarus Roeselii ; Glycogen ; Heat Production ; Invasive Species ; Metabolic Rate ; Locomotor Activity ; Triglyceride ; Chemistry ; Anatomy & Physiology
    ISSN: 1095-6433
    E-ISSN: 1531-4332
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  • 9
    Language: English
    In: Journal of Soils and Sediments, 2013, Vol.13(1), pp.197-206
    Description: Byline: Susanne Siebeneicher (1), Dierk-Steffen Wahrendorf (2), Markus A. Wetzel (2), Dirk Jungmann (1) Keywords: Bioassay; Burrowing behavior; Corophium volutator; Marine sediment; Sublethal toxicity Abstract: Purpose Acute whole-sediment bioassay with the estuarine and marine amphipod Corophium volutator (Pallas) is widely used to assess toxicity of sediments. According to the guidelines DIN EN ISO 16712, mortality is the determined toxic endpoint. Additionally, the reburrowing ability of the surviving organisms of this acute toxicity test in fresh uncontaminated sediment is suggested as the sublethal endpoint, but insufficient information (e.g., exact measurement protocols) on this endpoint is provided, thus confounding factors and the interpretation of the results. The aim of this study was to provide information on burrowing activity as a sublethal endpoint. Materials and methods Amphipod tests were carried out in the laboratory, and the burrowing behavior was examined in a size- and gender-specific manner. For sediment testing, only animals of the same size were used in a defined sex ratio because it was found that female animals buried themselves faster than males and that smaller animals burrowed faster than bigger organisms. Statistical analyses were applied to determine whether burrowing time and ability differ significantly between sexes and sizes. Finally, tests were run to discern whether the burrowing ability could be a more sensitive endpoint than mortality. Results and discussion When the burrowing ability was examined in toxicity tests with contaminated sediment, the test organisms were affected in a dose-dependent manner. With rising concentrations of the contaminated sediment in a sublethal testing following the sediment exposure over 10 days, fewer animals buried themselves into the sediment. Conclusions The burrowing behavior can be used as an additional endpoint. For the tested sediment, burrowing was found to be more sensitive than the mortality. Guidance on the measurement protocol for this additional endpoint was developed. Under the test conditions examined, burrowing ability is an appropriate sublethal endpoint to supplement the toxicity test procedure. Author Affiliation: (1) Institut fur Hydrobiologie, Technische Universitat Dresden, 01062, Dresden, Germany (2) Bundesanstalt fur Gewasserkunde, 56068, Koblenz, Germany Article History: Registration Date: 11/10/2012 Received Date: 06/10/2011 Accepted Date: 11/10/2012 Online Date: 25/10/2012 Article note: Responsible editor: Wolfgang Ahlf
    Keywords: Bioassay ; Burrowing behavior ; Corophium volutator ; Marine sediment ; Sublethal toxicity
    ISSN: 1439-0108
    E-ISSN: 1614-7480
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  • 10
    Language: English
    In: Ecological Indicators, November 2013, Vol.34, pp.323-331
    Description: In the context of the requirements of the European Water Framework Directive (WFD) numerous benthic indices have been proposed recently to assess the ecological quality of marine and transitional waters. In several studies these metrics were applied to coastal and estuarine environments under diverse anthropogenic pressures. Although currently the dumping of dredged material is one of the most prominent human impacts that modify estuaries, the performance of benthic indices to detect effects of dredged sediment relocation has not yet been tested explicitly. Hence we examined a selection of common metrics (species richness, Shannon diversity, AMBI, M-AMBI, -value, BO2A) at 11 dumping and 11 nearby reference areas in the highly modified Elbe estuary (Germany), where permanent dredging is necessary to maintain the depth of the navigation channel. In order to cover the entire estuary, the study area spanned over the whole salinity gradient from limnic to euhaline. Additionally, we investigated changes in benthic communities due to dredged material placement. All indices, except the -value, were suitable to differentiate between dumping and reference areas and showed significantly better index values exclusively at reference areas. The applicability of AMBI and M-AMBI was restricted in the limnic stretch due to the more frequent occurrence of freshwater species there. The -value and BO2A were non-satisfactory in the case of azoic sediment, and in most cases these two indices indicated much better ecological status classifications than the other indices tested. Furthermore, the BO2A had restricted applicability with increasing salinity. At eight of eleven sites the benthic communities differed significantly between dumping and reference areas. Our findings show that the power of conventional benthic indices to detect physical disturbances like the dumping of dredged sediment varies greatly. Having this in mind, we suggest to choose carefully the benthic indices for ecological quality assessments according to the WFD in estuaries in order to avoid misclassifications. Such errors may lead to unnecessarily expensive remediation activities or, in the opposite case, to inactivity although actions were necessary. Furthermore, in order to better meet the WFD requirements we suggest that, regarding frequency and volume, dumping should be adapted as far as possible to the natural processes of sediment movement.
    Keywords: Macrofauna ; Benthic Community Structure ; Wfd ; Elbe Estuary ; Benthic Indices ; Dumping of Dredged Material ; Environmental Sciences
    ISSN: 1470-160X
    E-ISSN: 1872-7034
    Source: ScienceDirect Journals (Elsevier)
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