Staff Publications

Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

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    Sustainability assessment of salmonid feed using energy, classical exergy and eco-exergy analysis
    Draganovic, V. ; Jorgensen, S.E. ; Boom, R.M. ; Jonkers, J. ; Goot, A.J. van der - \ 2013
    Ecological Indicators 34 (2013). - ISSN 1470-160X - p. 277 - 289.
    krill euphausia-superba - life-cycle assessment - environmental impacts - production systems - farmed salmon - ethanol - organisms - products - chains - wheat
    Reduction of the environmental impact of feed products is of paramount importance for salmon farming. This article explores the potential to compare three thermodynamically based ecological indicators. The environmental impact of partial replacement of fish meal (FM) and fish oil with alternative ingredients was investigated using energy, classical exergy and eco-exergy analysis. Seven hypothetical feeds were formulated: one with high levels of FM and fish oil, four feeds based on plant ingredients, one containing krill meal, and one based on algae-derived products. Analysis included cultivation of crops and algae, fishing for fish and krill, industrial processing of these ingredients and production of complete fish feed. Because most harvested products are refined in multiple product outputs that have good value to society, two scenarios were compared. In the base case scenario, no allocation of co-products was used and all the environmental costs were ascribed to one specific co-product. Co-product allocation by mass was used in the second scenario; this is considered to be the preferred scenario because it accurately reflects the individual contributions of the co-products to the environmental impact of the feed products. For this scenario, the total energy consumption for a fish-based diet was 14,500 MJ, which was similar to a krill diet (15,600 MJ), about 15–31% higher than plant-based diets, and 9% higher than an algae diet. Substituting FM and fish oil with alternative ingredients resulted in minor changes in total classical exergy degradation (2–16% difference). The calculations based on energy only consider the energy conservation based on the First Law of Thermodynamics, whereas those based on classical exergy also takes the Second Law of Thermodynamics into account; energy that can do work is distinguished from energy that is lost as heat to the environment. The calculations based on eco-exergy consider the total loss of work energy in the environment including the work energy associated with the information embodied in the genomes of organisms. The diet based on fishery-derived ingredients was the highest total work energy consumer compared with plant-based diets (24–30% greater), the diet containing krill meal (25% greater), and the algae diet (four times higher). Thus, reducing FM and fish oil levels in fish feed can contribute significantly to more sustainable aquaculture. In particular, algae-derived products in aquafeeds could drastically decrease environmental costs in the future.
    Towards quantitave ecological risk assessment of elevated carbon dioxide levels in the marine environment
    Vries, P. de; Tamis, J.E. ; Foekema, E.M. ; Klok, T.C. ; Murk, A.J. - \ 2013
    Marine Pollution Bulletin 73 (2013)2. - ISSN 0025-326X - p. 516 - 523.
    species-sensitivity distributions - ocean acidification - extrapolation models - acute toxicity - co2 capture - organisms - storage - assumptions - ecosystems - leakage
    The environmental impact of elevated carbon dioxide (CO2) levels has become of more interest in recent years. This, in relation to globally rising CO2 levels and related considerations of geological CO2 storage as a mitigating measure. In the present study effect data from literature were collected in order to conduct a marine ecological risk assessment of elevated CO2 levels, using a Species Sensitivity Distribution (SSD). It became evident that information currently available from the literature is mostly insufficient for such a quantitative approach. Most studies focus on effects of expected future CO2 levels, testing only one or two elevated concentrations. A full dose-response relationship, a uniform measure of exposure, and standardized test protocols are essential for conducting a proper quantitative risk assessment of elevated CO2 levels. Improvements are proposed to make future tests more valuable and usable for quantitative risk assessment.
    Ecosystem engineering by seagrasses interacts with grazing to shape an intertidal landscape
    Heide, T. van der; Eklof, J.S. ; Nes, E.H. van; Zee, E.M. van der; Donadi, S. ; Weerman, E. ; Olff, H. ; Eriksson, B.K. - \ 2012
    PLoS ONE 7 (2012)8. - ISSN 1932-6203
    spatial vegetation patterns - geese branta-bernicla - brent geese - arid ecosystems - zostera-noltii - wadden sea - dynamics - organisms - desertification - exploitation
    Self-facilitation through ecosystem engineering (i.e., organism modification of the abiotic environment) and consumer-resource interactions are both major determinants of spatial patchiness in ecosystems. However, interactive effects of these two mechanisms on spatial complexity have not been extensively studied. We investigated the mechanisms underlying a spatial mosaic of low-tide exposed hummocks and waterlogged hollows on an intertidal mudflat in the Wadden Sea dominated by the seagrass Zostera noltii. A combination of field measurements, an experiment and a spatially explicit model indicated that the mosaic resulted from localized sediment accretion by seagrass followed by selective waterfowl grazing. Hollows were bare in winter, but were rapidly colonized by seagrass during the growth season. Colonized hollows were heavily grazed by brent geese and widgeon in autumn, converting these patches to a bare state again and disrupting sediment accretion by seagrass. In contrast, hummocks were covered by seagrass throughout the year and were rarely grazed, most likely because the waterfowl were not able to employ their preferred but water requiring feeding strategy ('dabbling') here. Our study exemplifies that interactions between ecosystem engineering by a foundation species (seagrass) and consumption (waterfowl grazing) can increase spatial complexity at the landscape level
    Multicenter Collaborative Trial Evaluation of a Method for Detection of Human Adenoviruses in Berry Fruit
    Agostino, C. D'; Cook, N. ; Bartolo, I. Di; Ruggeri, F.M. ; Berto, A. ; Martelli, F. ; Banks, M. ; Vasickova, P. ; Kralik, P. ; Pavlik, I. ; Kokkinos, P. ; Vantarakis, A. ; Söderberg, K. ; Maunula, L. ; Verhaelen, K. ; Rutjes, S. ; Roda Husman, A.M. De; Hakze-van der Honing, R.W. van der; Poel, W.H.M. van der; Kaupke, A. ; Kozyra, I. ; Rzezutka, A. ; Prodanov, J. ; Lazic, S. ; Petrovic, T. ; Carratala, A. ; Gironés, R. ; Diez-Valcarce, M. ; Hernandez, M. ; Rodriguez-Lazaro, D. - \ 2012
    Food Analytical Methods 5 (2012)1. - ISSN 1936-9751 - p. 1 - 7.
    pcr-based method - listeria-monocytogenes - international standard - enteric viruses - food - validation - water - contamination - environment - organisms
    The qualitative performance characteristics of a qPCR-based method to detect human adenoviruses in raspberries were determined through a collaborative trial involving 11 European laboratories. The method incorporated a sample process control (murine norovirus) and an internal amplification control. Trial sensitivity or correct identification of 25-g raspberry samples artificially contaminated with between 5×102 and 5×104 PFU was 98.5%; the accordance and concordance were 97.0%. The positive predictive value was 94.2%. The trial specificity or percentage correct identification of non-artificially contaminated samples was 69.7%; the accordance was 80.0% and the concordance was 61.7%. The negative predictive value was 100%. Application of a method for the detection of human adenoviruses in food samples could be useful for routine monitoring for food safety management. It would help to determine if a route of contamination exists from human source to food supply chain which pathogenic viruses such as norovirus and hepatitis A virus could follow.
    High-Resolution Mapping of Two Broad-Spectrum Late Blight Resistance Genes from Two Wild Species of the Solanum circaeifolium Group
    Verzaux, E.C. ; Arkel, G. van; Vleeshouwers, V.G.A.A. ; Vossen, E.A.G. van der; Niks, R.E. ; Jacobsen, E. ; Vossen, J.H. ; Visser, R.G.F. - \ 2012
    Potato Research 55 (2012)2. - ISSN 0014-3065 - p. 109 - 123.
    phytophthora-infestans resistance - potato-virus-y - disease resistance - nb-lrr - plants - cisgenesis - strategies - organisms - cloning - genome
    High levels of resistance to Phytophthora infestans in Solanum are predominantly based on the gene-for-gene interaction. Identification of hitherto unknown R genes is essential for future pyramiding approaches. This could be achieved either through classic introgression breeding or through cisgenesis and could lead to sustainable control of late blight. Here, we report on the mapping of Rpi-cap1 and Rpi-qum1, two late blight R genes identified in the wild species Solanum capsicibaccatum and Solanum circaeifolium ssp. quimense, respectively, to very similar positions on the long arm of chromosome 11. Despite the difficulties encountered for marker development, a high-resolution genetic map with cleaved amplified polymorphic sequence markers was constructed. Furthermore, an R gene cluster-directed profiling approach led to the development of markers that closely
    Reconstruction of the Ethnical Debate on Naturalness in discussion about Plant-Biotechnology
    Haperen, P.F. van; Gremmen, H.G.J. ; Jacobs, J.G.M. - \ 2012
    Journal of Agricultural and Environmental Ethics 25 (2012)6. - ISSN 1187-7863 - p. 797 - 812.
    consequences - propagation - environment - organisms - genome - gene
    This paper argues that in modern (agro)biotechnology, (un)naturalness as an argument contributed to a stalemate in public debate about innovative technologies. Naturalness in this is often placed opposite to human disruption. It also often serves as a label that shapes moral acceptance or rejection of agricultural innovative technologies. The cause of this lies in the use of nature as a closed, static reference to naturalness, while in fact ‘‘nature’’ is an open and dynamic concept with many different meanings. We propose an approach for a dynamic framework that permits an integrative use of naturalness in debate, by connecting three sorts of meaning that return regularly in the arguments brought forward in debate; cultural, technological, and ecological. We present these as aspects of nature that are always present in the argument of naturalness. The approach proposes a dynamic relation between these aspects, formed by gradients of naturalness, which in turn are related to ethical concerns. In this way we come to an overview that makes it possible to give individual arguments a relative place and that does justice to the temporality of the concept of nature and the underlying ethical concerns stakeholders have in respect to innovation in agriculture.
    Wave Attenuation by Two Contrasting Ecosystem Engineering Salt Marsh Macrophytes in the Intertidal Pioneer Zone
    Ysebaert, T. ; Yang, S.L. ; Zhang, L.Q. ; He, Q. ; Bouma, T.J. ; Herman, P.M.J. - \ 2011
    Wetlands 31 (2011)6. - ISSN 0277-5212 - p. 1043 - 1054.
    yangtze-river - spartina-alterniflora - vegetation - organisms - patterns - wetlands - china - delta - field - flow
    Tidal wetlands play an important role in dissipating hydrodynamic energy. Wave attenuation in vegetation depends on plant characteristics, as well as on hydrodynamic conditions. In the pioneer zone of salt marshes, species co-occur that differ widely in their growth strategies, and it is anticipated that these species act differently on incoming waves. In this field study we investigated, under different hydrodynamic forcing and tidal inundation levels, the wave attenuating capacity of two contrasting pioneer salt marsh species that co-occur in the Yangtze estuary, China. Our study shows that vegetation can reduce wave heights up to 80% over a relatively short distance (<50 m). Our results further indicate that Spartina alterniflora is able to reduce hydrodynamic energy from waves to a larger extent than Scirpus mariqueter, and therefore has a larger ecosystem engineering capacity (2.5x higher on average). A higher standing biomass of S. alterniflora explained its higher wave attenuation at low water depths. Being much taller compared to S. mariqueter, S. alterniflora also attenuated waves more with increasing water depth. We conclude that knowledge about the engineering properties of salt marsh species is important to better understand wave attenuation by tidal wetlands and their possible role in coastal protection.
    A workflow for peptide-based proteomics in a poorly sequenced plant: A case study on the plasma membrane proteome of banana
    Vertommen, A. ; Moller, A. ; Cordewener, J.H.G. ; Swennen, R. ; Panis, B. ; Finnie, C. ; America, A.H.P. ; Carpentier, S.C. - \ 2011
    Journal of Proteomics 74 (2011)8. - ISSN 1874-3919 - p. 1218 - 1229.
    driven proteomics - lc-ms/ms - proteins - identification - organisms - system
    Membrane proteins are an interesting class of proteins because of their functional importance. Unfortunately their analysis is hampered by low abundance and poor solubility in aqueous media. Since shotgun methods are high-throughput and partly overcome these problems, they are preferred for membrane proteomics. However, their application in non-model plants demands special precautions to prevent false positive identification of proteins. In the current paper, a workflow for membrane proteomics in banana, a poorly sequenced plant, is proposed. The main steps of this workflow are (i) optimization of the peptide separation, (ii) performing de novo sequencing to allow a sequence homology search and (iii) visualization of identified peptide–protein associations using Cytoscape to remove redundancy and wrongly assigned peptides, based on species-specific information. By applying this workflow, integral plasma membrane proteins from banana leaves were successfully identified.
    Baculovirus cyclobutane pyrimidine dimer photolyases show a close relationship with lepidopteran host homologues
    Biernat, M.A. ; Ros, V.I.D. ; Vlak, J.M. ; Oers, M.M. van - \ 2011
    Insect Molecular Biology 20 (2011)4. - ISSN 0962-1075 - p. 457 - 464.
    dna photolyase - chrysodeixis-chalcites - sequence - genome - genes - nucleopolyhedroviruses - organisms - evolution
    Cyclobutane pyrimidine dimer (CPD) photolyases repair ultraviolet (UV)-induced DNA damage using blue light. To get insight in the origin of baculovirus CPD photolyase (phr) genes, homologues in the lepidopteran insects Chrysodeixis chalcites, Spodoptera exigua and Trichoplusia ni were identified and characterized. Lepidopteran and baculovirus phr genes each form a monophyletic group, and together form a well-supported clade within the insect photolyases. This suggests that baculoviruses obtained their phr genes from an ancestral lepidopteran insect host. A likely evolutionary scenario is that a granulovirus, Spodoptera litura GV or a direct ancestor, obtained a phr gene. Subsequently, it was horizontally transferred from this granulovirus to several group II nucleopolyhedroviruses (NPVs), including those that infect noctuids of the Plusiinae subfamily.
    Modification of light utilization for skeletal growth by water flow in the scleractinian coral Galaxea fascicularis
    Schutter, M. ; Kranenbarg, S. ; Wijffels, R.H. ; Verreth, J.A.J. ; Osinga, R. - \ 2011
    Marine Biology 158 (2011)4. - ISSN 0025-3162 - p. 769 - 777.
    reef coral - madracis-mirabilis - photosynthesis - calcification - oxygen - respiration - rates - temperatures - mechanisms - organisms
    In this study, we tested the hypothesis that the importance of water flow for skeletal growth (rate) becomes higher with increasing irradiance levels (i.e. a synergistic effect) and that such effect is mediated by a water flow modulated effect on net photosynthesis. Four series of nine nubbins of G. fascicularis were grown at either high (600 µE m-2 s-1) or intermediate (300 µE m-2 s-1) irradiance in combination with either high (15–25 cm s-1) or low (5–10 cm s-1) flow. Growth was measured as buoyant weight and surface area. Photosynthetic rates were measured at each coral’s specific experimental irradiance and flow speed. Additionally, the instantaneous effect of water flow on net photosynthetic rate was determined in short-term incubations in a respirometric flowcell. A significant interaction was found between irradiance and water flow for the increase in buoyant weight, the increase in surface area, and specific skeletal growth rate, indicating that flow velocity becomes more important for coral growth with increasing irradiance levels. Enhancement of coral growth with increasing water flow can be explained by increased net photosynthetic rates. Additionally, the need for costly photo-protective mechanisms at low flow regimes could explain the differences in growth with flow.
    Quantitative Proteomic Analysis of Sulfolobus solfataricus Membrane Proteins
    Pham, T.K. ; Sierocinski, P. ; Oost, J. van der; Wright, P.C. - \ 2010
    Journal of Proteome Research 9 (2010)2. - ISSN 1535-3893 - p. 1165 - 1172.
    2-dimensional gel-electrophoresis - mass-spectrometry - halophilic archaeon - signal peptides - isobaric tags - p2 proteome - metabolism - genome - identification - organisms
    A quantitative proteomic analysis of the membrane of the archaeon Sulfolobus solfataricus P2 using iTRAQ was successfully demonstrated in this technical note. The estimated number of membrane proteins of this organism is 883 (predicted based on Gravy score), corresponding to 30 % of the total number of proteins. Using a modified iTRAQ protocol for membrane protein analysis, of the 284 proteins detected, 246 proteins were identified as membrane proteins, whilst using an original iTRAQ protocol, 147 proteins were detected with only 133 proteins being identified as membrane proteins. Furthermore, 97.2% of proteins identified in the modified protocol contained more than 2 distinct peptides compared to the original workflow. The successful application of this modified protocol offers a potential technique for quantitatively analyzing membrane-associated proteomes of organisms in the archaeal kingdom. The combination of 3 different iTRAQ experiments resulted in the detection of 395 proteins (>/= 2 distinct peptides) of which 373 had predicted membrane properties. Approximately 20% of the quantified proteins were observed to exhibit >/= 1.5 fold differential expression at temperatures well below the optimum for growth
    Cultivation of the heart urchin Echinocardium cordatum and validation of its use in marine toxicity testing for environmental risk assessment
    Schipper, C.A. ; Dubbeldam, M. ; Feist, S.W. ; Rietjens, I.M.C.M. ; Murk, A.J. - \ 2008
    Journal of Experimental Marine Biology and Ecology 364 (2008)1. - ISSN 0022-0981 - p. 11 - 18.
    paracentrotus-lividus echinodermata - sea-urchin - north-sea - corophium-volutator - growth - sediments - bioassays - echinoidea - organisms - amphipod
    To study environmental risk assessment, echinoderms provide a useful model for ecotoxicological testing. However, limited knowledge of the life history of field collected heart urchins is a problem and the use of cultured urchins has been investigated here. The present study describes a culture method for the heart urchin Echinocardium cordatum under controlled laboratory conditions, providing organisms with a low biological variation. Based on our optimized growth protocol both larvae and juveniles have a growth rate comparable to E. cordatum in the wild. The toxicological response of cultured and field-collected E. cordatum was compared in standard saltwater toxicity bioassays. Using ammonium chloride as a water-soluble reference toxicant, mean 96 h LC50 values for cultured heart urchins versus field collected animals were 37.4 ± 7.6 mg NH4+/l (n = 5) versus 22.5 ± 4.9 mg NH4+/l (n = 19), respectively. Additional toxicity experiments with tributyl tin (TBT) spiked sediments revealed 14d LC50 values of 1,242 (95% confidence interval 986¿1,564) and 964 (95% confidence interval 843¿1,102) µg Sn/kg dw respectively in cultured and field collected E. cordatum. From this it was concluded that cultured heart urchins are less sensitive to TBT than field collected E. cordatum. Furthermore in whole sediment toxicity tests, survival of cultured sea urchins was higher or at least similar to that of field collected E. cordatum. The increased sensitivity of field urchins compared to cultured urchins in various toxicity tests may be due to multiple environmental stressors reducing their overall performance. Overall it was demonstrated that the use of cultured E. cordatum provides a significant advance for urchin-based bioassays for marine environmental toxicity testing, resulting in a more homogeneous, vital population with experimental data displaying reduced variability.
    Development and application of a species sensitivity distribution for temperature-induced mortality in the aquatic environment
    Vries, P. de; Tamis, J.E. ; Murk, A.J. ; Smit, M.G.D. - \ 2008
    Environmental Toxicology and Chemistry 27 (2008)12. - ISSN 0730-7268 - p. 2591 - 2598.
    risk assessment - extrapolation models - tolerance - toxicity - field - organisms - fishes - growth
    Current European legislation has static water quality objectives for temperature effects, based on the most sensitive species. In the present study a species sensitivity distribution (SSD) for elevated temperatures is developed on the basis of temperature sensitivity data (mortality) of 50 aquatic species. The SSD applies to risk assessment of heat discharges that are localized in space or time. As collected median lethal temperatures (LT50 values) for different species depend on the acclimation temperature, the SSD is also a function of the acclimation temperature. Data from a thermal discharge in The Netherlands are used to show the applicability of the developed SSD in environmental risk assessment. Although restrictions exist in the application of the developed SSD, it is concluded that the SSD approach can be applied to assess the effects of elevated temperature. Application of the concept of SSD to temperature changes allows harmonization of environmental risk assessment for stressors in the aquatic environment. When a synchronization of the assessment methods is achieved, the steps to integration of risks from toxic and nontoxic stressors can be made.
    Cisgenesis and intragenesis, sisters in innovative plant breeding
    Schouten, H.J. ; Jacobsen, E. - \ 2008
    Trends in Plant Science 13 (2008)6. - ISSN 1360-1385 - p. 260 - 261.
    The consequences of changes in abundance of Callianassa subterranea and Amphiura filiformis on sediment erosion at the Frisian Front (south-eastern North Sea)
    Amaro, T.P.F. ; Duineveld, G.C.A. ; Bergman, M.J.N. ; Witbaard, R. ; Scheffer, M. - \ 2007
    Hydrobiologia 589 (2007)1. - ISSN 0018-8158 - p. 273 - 285.
    montagu thalassinidea - ecosystem engineers - resuspension - disturbance - dynamics - growth - echinodermata - ophiuroidea - macrofauna - organisms
    In the early 1990¿s a conspicuous shift took place in the density of two key macrofauna species at the Frisian Front (SE North Sea). The density of the formerly dominant brittlestar Amphiura filiformis showed tenfold reduction and remained low throughout the observation period (1986¿2000). In the same period, the burrowing mud shrimp Callianassa subterranea showed a fourfold increase in density. Since the Frisian Front is a transition area where tidal currents fall just below the erosion threshold of silt and bioturbating mud shrimps can potentially affect the sediment erosion threshold, we examined the effects of the species on sediment erodibility. Two experiments were conducted in laboratory annular flumes. In the first experiment we compared the effects of pre-shift and post-shift combinations of the two species on the erodibility of Frisian Front sediment. The results indicated that the erosion was facilitated by a combination of high densities of C. subterranea and low densities of A. filiformis, representing the situation in the late 1990s. The difference in erodibility was already apparent at velocities equal to the critical near-bed current speed measured at the Frisian Front. In the second experiment the effects of pre- and post-shift densities of A. filiformis on sediment erodibility were compared. This showed that low A. filiformis densities as found in the late 1990¿s facilitate erosion, but the effect is only significant at velocities above the critical near-bed velocity in the field. At the latter velocity, no significant difference in erodibility was found between the two A. filiformis densities. This implies that the difference in turbidity in the first experiment was mainly due to the activity of C. subterranea. The experimental results indicate that resuspension at the Frisian Front may occur more frequently as a result of the shift towards a Callianassa dominated community. More frequent resuspension of bottom sediment, most likely amplified by the climate induced increase of wind strength in the North Sea, may hamper the recovery of the A. filiformis adult population.
    Effects of earthworms density on growth, development and reproduction in Lumbricus rubellus (Hoffm.) and possible consequences for the intrinsic rate of population increase
    Klok, C. - \ 2007
    Soil Biology and Biochemistry 39 (2007)9. - ISSN 0038-0717 - p. 2401 - 2407.
    burrow systems - oligochaeta - dynamics - soil - organisms - culture - cores
    In this paper, the influence of earthworm density is assessed on the life-history parameters: growth, development, reproduction, and survival of Lumbricus rubellus (Hoffm.). Density ranges from two to nine earthworms in 1-1 containers, corresponding to field densities of 300-1350 earthworms m(-2). Earthworms were kept under optimal laboratory conditions, with a surplus of food. The results show that at high earthworm density, individual growth is retarded, maturation delayed and cocoon production decreased, even when food is optimal. The integration of these results into a Dynamic Energy Budget model suggests that the food intake of individual earthworms is lower at the higher tested densities. This lower food intake is most probably driven by competition for space at the higher densities. The lower food intake results in a lower intrinsic rate of population increase which is negative at the highest tested density. (C) 2007 Elsevier Ltd. All rights reserved.
    Reply to 'Cisgenic' as a product designation
    Schouten, H.J. ; Krens, F.A. ; Jacobsen, E. - \ 2006
    Nature Biotechnology 24 (2006)11. - ISSN 1087-0156 - p. 1331 - 1333.
    cisgenic plants - organisms - genomics - lessons - gene
    Ecological effects of Spring and late Summer applications of Lambda-Cyhalothrin on freshwater microcosms
    Wijngaarden, R.P.A. van; Brock, T.C.M. ; Brink, P.J. van den; Gylstra, R. ; Maund, S.J. - \ 2006
    Archives of Environmental Contamination and Toxicology 50 (2006)2. - ISSN 0090-4341 - p. 220 - 239.
    toxiciteit - zoetwaterecologie - lambda-cyhalothrin - seizoenen - lente - zomer - oppervlaktewater - sloten - toxicity - freshwater ecology - lambda-cyhalothrin - seasons - spring - summer - surface water - ditches - active ingredient chlorpyrifos - insecticide dursban(r) 4e - aquatic risk-assessment - community responses - fate - zooplankton - organisms - mesocosms - recovery
    The aim of the study was to compare the effects of the pyrethroid insecticide lambda-cyhalothrin (treated at 10, 25, 50, 100, 250 ng active ingredient a.i./L) on a drainage ditch ecosystem in spring and late summer. Microcosms (water volume approximately 430 L) were established using enclosures in a 50-cm¿deep experimental ditch system containing communities typical of macrophyte-dominated freshwater ecosystems. Effects on macroinvertebrates, zooplankton, phytoplankton, macrophytes, and community metabolism were assessed and evaluated using univariate and multivariate statistical techniques. The macroinvertebrate community responded most clearly to treatment and, as anticipated, insects and crustaceans were among the most sensitive organisms. Statistical analysis showed that the underlying community structure was significantly different between the spring and summer experiments. However, the most sensitive species (Chaoborus obscuripes and Gammarus pulex) were abundant in spring as well as in late summer. In spring and late summer, only slight and transient effects were observed at the community level in the 10-ng/L treatment. Overall, the study did not show substantial differences in the responses of sensitive taxa between spring and late summer treatments, and effects thresholds were similar irrespective of season of treatment.
    The need to differentiate Campylobacter fetus subspecies isolated from humans, correspondence
    Kalka-Moll, W.M. ; Bergen, M.A.P. van; Plum, G. ; Kronke, M. ; Wagenaar, J.A. - \ 2005
    Clinical Microbiology and Infection 11 (2005)4. - ISSN 1198-743X - p. 341 - 342.
    bacteremia - organisms - pcr
    The use of earthworms in ecological soil classification and assessment concepts
    Rombke, J. ; Jansch, S. ; Didden, W.A.M. - \ 2005
    Ecotoxicology and Environmental Safety 62 (2005)2 sp. iss.. - ISSN 0147-6513 - p. 249 - 265.
    ecosystem engineers - southern sweden - heavy-metals - forest soil - populations - lumbricidae - oligochaeta - organisms - profiles - invertebrates
    Without doubt, earthworms are the most important soil invertebrates in most soils worldwide, in terms of both biomass and activity. Several species are even considered to be ecosystem engineers. Earthworms are also known to influence soil structure, soil chemistry, and, in particular, processes like organic matter decomposition. In addition, standardized sampling methods are available and their taxonomy is well known (even the first PC-aided keys have been developed). For these reasons, earthworms were recognized as a part of ecological classification and assessment schemes early on. However, due to the relatively small number at many sites, they have to be part of a battery approach. By use of examples from The Netherlands (biological indicator of soil quality) and Germany (soil biological site classification), the practicability of the use of earthworms is demonstrated in determining the influence of different anthropogenic land use forms. In these cases, the structure of the earthworm community, as well as their abundance and biomass, were used as endpoints.
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