The Experts below are selected from a list of 309 Experts worldwide ranked by ideXlab platform
Miquel Lürling - One of the best experts on this subject based on the ideXlab platform.
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Effects of a surfactant (FFD-6) on Scenedesmus morphology and growth under different nutrient conditions.
Chemosphere, 2005Co-Authors: Miquel LürlingAbstract:Surfactants are man-made compounds that are meanwhile omnipresent in the environment, but environmental concentrations of surfactants are such that they are thought to have little risk for aquatic systems. The major anionic surfactants currently on the global market are linear alkylbenzene sulfonates (LAS), a class where the commercially available FFD-6 belongs to. The hypothesis was tested that sublethal effects of FFD-6, i.e. the morphological effect of colony formation in the common test alga Scenedesmus obliquus, occurs at a concentration lower than the no-observed-effect concentrations for endpoints commonly used in regulatory toxicity testing with algae. The surfactant FFD-6 induced colonies in Scenedesmus at concentrations a few orders of magnitude lower (i.e. between 0.001 and 0.01 g l-1) than at which growth inhibition was observed (i.e. between 1 and 10g l -1). Growth rates were lowest for Scenedesmus grown in P-limited medium, intermediate for algae reared in N-limited medium and highest for algae cultured in non-limited standard medium. Growth inhibition due to FFD-6 was similar for non-limited and nutrient-limited Scenedesmus, but colony formation was stronger in non-limited Scenedesmus than in nutrient limited cultures. The colony inducing effect of the surfactant FFD-6 on Scenedesmus occurs at much lower concentrations than growth inhibition and might affect species interactions, the survival of species and the energy flow along the food chain.
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SEQUENCE ANALYSIS OF THE ITS-2 REGION: A TOOL TO IDENTIFY STRAINS OF Scenedesmus (CHLOROPHYCEAE).
Journal of phycology, 2000Co-Authors: Erik J Van Hannen, Miquel Lürling, Ellen Van DonkAbstract:The genetic distances between several strains of Senedesmus obliquus (Turp,) Kutz,, S, acutus Hortobagyi, and S, naegelii Chod. calculated from ITS-2 sequences were found to be smaller than the genetic distances within other strains of Scenedesmus-that is, in S, acuminatus (Lagerh,) Chod, and S, pectinatus Meyen. These results confirm that the studied strains were not properly identified and should be renamed S, obliquus, as already suggested in other studies. [KEYWORDS: ITS, phylogeny, Scenedesmus acutus, Scenedesmus naegelii, Scenedesmus obliquus]
E. T. H. M. Peeters - One of the best experts on this subject based on the ideXlab platform.
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Effects of an anionic surfactant (FFD-6) on the energy and information flow between a primary producer (Scenedesmus obliquus) and a consumer (Daphnia magna)
Ecotoxicology, 2011Co-Authors: M. Lürling, H. J. Lange, E. T. H. M. PeetersAbstract:The effects of a commercially available anionic surfactant solution (FFD-6) on growth and morphology of a common green alga ( Scenedesmus obliquus ) and on survival and clearance rates of the water flea Daphnia magna were studied. The surfactant-solution elicited a morphological response (formation of colonies) in Scenedesmus at concentrations of 10–100 μl l^−1 that were far below the No Observed Effect Concentration (NOEC) value of 1,000 μl l^−1 for growth inhibition. The NOEC-value of FFD-6 for colony-induction was 3 μl l^−1. Daphnia survival was strongly affected by FFD-6, yielding LC_50–24h and LC_50–48h of 148 and 26 μl l^−1, respectively. In addition, clearance rates of Daphnia feeding on unicellular Scenedesmus were inhibited by FFD-6, yielding a 50% inhibition (EC_50–1.5h) at 5.2 μl l^−1 with a NOEC of 0.5 μl l^−1. When Daphnia were offered FFD-6-induced food in which eight-celled colonies (43 × 29 μm) were most abundant, clearance rates (~0.14 ml ind.^−1 h^−1) were only 25% the rates of animals that were offered non-induced unicellular (15 × 5 μm) Scenedesmus (~0.56 ml ind.^−1 h^−1). As FFD-6 concentrations in the treated food used in the experiments were far below the NOEC for clearance rate inhibition, it is concluded that the feeding rate depression was caused by the altered morphology of the Scenedesmus moving them out of the feeding window of the daphnids. The surfactant evoked a response in Scenedesmus that is similar to the natural chemically induced defensive reaction against grazers and could disrupt the natural information conveyance between these plankton organisms.
M. Lürling - One of the best experts on this subject based on the ideXlab platform.
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Effects of an anionic surfactant (FFD-6) on the energy and information flow between a primary producer (Scenedesmus obliquus) and a consumer (Daphnia magna)
Ecotoxicology, 2011Co-Authors: M. Lürling, H. J. Lange, E. T. H. M. PeetersAbstract:The effects of a commercially available anionic surfactant solution (FFD-6) on growth and morphology of a common green alga ( Scenedesmus obliquus ) and on survival and clearance rates of the water flea Daphnia magna were studied. The surfactant-solution elicited a morphological response (formation of colonies) in Scenedesmus at concentrations of 10–100 μl l^−1 that were far below the No Observed Effect Concentration (NOEC) value of 1,000 μl l^−1 for growth inhibition. The NOEC-value of FFD-6 for colony-induction was 3 μl l^−1. Daphnia survival was strongly affected by FFD-6, yielding LC_50–24h and LC_50–48h of 148 and 26 μl l^−1, respectively. In addition, clearance rates of Daphnia feeding on unicellular Scenedesmus were inhibited by FFD-6, yielding a 50% inhibition (EC_50–1.5h) at 5.2 μl l^−1 with a NOEC of 0.5 μl l^−1. When Daphnia were offered FFD-6-induced food in which eight-celled colonies (43 × 29 μm) were most abundant, clearance rates (~0.14 ml ind.^−1 h^−1) were only 25% the rates of animals that were offered non-induced unicellular (15 × 5 μm) Scenedesmus (~0.56 ml ind.^−1 h^−1). As FFD-6 concentrations in the treated food used in the experiments were far below the NOEC for clearance rate inhibition, it is concluded that the feeding rate depression was caused by the altered morphology of the Scenedesmus moving them out of the feeding window of the daphnids. The surfactant evoked a response in Scenedesmus that is similar to the natural chemically induced defensive reaction against grazers and could disrupt the natural information conveyance between these plankton organisms.
H. J. Lange - One of the best experts on this subject based on the ideXlab platform.
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Effects of an anionic surfactant (FFD-6) on the energy and information flow between a primary producer (Scenedesmus obliquus) and a consumer (Daphnia magna)
Ecotoxicology, 2011Co-Authors: M. Lürling, H. J. Lange, E. T. H. M. PeetersAbstract:The effects of a commercially available anionic surfactant solution (FFD-6) on growth and morphology of a common green alga ( Scenedesmus obliquus ) and on survival and clearance rates of the water flea Daphnia magna were studied. The surfactant-solution elicited a morphological response (formation of colonies) in Scenedesmus at concentrations of 10–100 μl l^−1 that were far below the No Observed Effect Concentration (NOEC) value of 1,000 μl l^−1 for growth inhibition. The NOEC-value of FFD-6 for colony-induction was 3 μl l^−1. Daphnia survival was strongly affected by FFD-6, yielding LC_50–24h and LC_50–48h of 148 and 26 μl l^−1, respectively. In addition, clearance rates of Daphnia feeding on unicellular Scenedesmus were inhibited by FFD-6, yielding a 50% inhibition (EC_50–1.5h) at 5.2 μl l^−1 with a NOEC of 0.5 μl l^−1. When Daphnia were offered FFD-6-induced food in which eight-celled colonies (43 × 29 μm) were most abundant, clearance rates (~0.14 ml ind.^−1 h^−1) were only 25% the rates of animals that were offered non-induced unicellular (15 × 5 μm) Scenedesmus (~0.56 ml ind.^−1 h^−1). As FFD-6 concentrations in the treated food used in the experiments were far below the NOEC for clearance rate inhibition, it is concluded that the feeding rate depression was caused by the altered morphology of the Scenedesmus moving them out of the feeding window of the daphnids. The surfactant evoked a response in Scenedesmus that is similar to the natural chemically induced defensive reaction against grazers and could disrupt the natural information conveyance between these plankton organisms.
Amir-hashim Mohd-kassim - One of the best experts on this subject based on the ideXlab platform.
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Nutrient Recovery from Domestic Effluent using an Indigenous Strain of Scenedesmus sp.
CLEAN - Soil Air Water, 2018Co-Authors: Radin Maya Saphira Radin Mohamed, Adel Al-gheethi, Ramlah Buyong, Nor Haslina Hashim, Hazel Monica Matias-peralta, Amir-hashim Mohd-kassimAbstract:The performance of a Scenedesmus sp. in the phycoremediation of domestic secondary effluents and the high‐quality production of the effluents for safe disposal were investigated in the current work. An indigenous strain of a Scenedesmus sp. was obtained from a sludge thickness basin at a wastewater treatment plant. The characteristics of this microalgae were identified using a molecular analysis based on 18S ribosomal RNA sequences. The phycoremediation process was conducted in a photoreactor tank (5 L) with five different concentrations of a Scenedesmus sp. (between 10⁵ and 10⁶ cells mL–1). The reactors were then placed outdoors (exposed to natural environmental conditions) for eight days. The Scenedesmus sp. had the ability to remove 91.86, 98.15 and 93.11% of total nitrogen (TN), total phosphorus (TP) and total organic carbon (TOC), respectively, and reduce biochemical oxygen demand (BOD), chemical oxygen demand (COD) and total suspended solid (TSS) by 86.5, 69.9 and 76%, respectively, at a concentration of 10⁶ cells mL–1. Moreover, the increase in the pH value during microalgae activity contributed to the increases in nutrients and characteristics percentage removal. The treated secondary effluents generated from the phycoremediation process after eight days met the EQA 1974 (Regulation 2009) sewage sludge (standard A) in terms of TN and TP but was still not under the permissible limits for BOD, COD and TSS. In conclusion, an indigenous Scenedesmus sp. was efficient in enhancing the quality of secondary wastewater to meet the standards required for reuse or safe disposal.
