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- Eriksson, Martin, 1970, et al.
(författare)
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Community-Level Analysis of psbA Gene Sequences and Irgarol Tolerance in Marine Periphyton
- 2009
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Ingår i: Applied and Environmental Microbiology. - Washington, D.C. : American Society for Microbiology. - 0099-2240 .- 1098-5336. ; 75:4, s. 897-906
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Tidskriftsartikel (refereegranskat)abstract
- This study analyzes psbA gene sequences, predicted D1 protein sequences, species relative abundance, and pollution-induced community tolerance in marine periphyton communities exposed to the antifouling compound Irgarol 1051. The mechanism of action of Irgarol is the inhibition of photosynthetic electron transport at photosystem II by binding to the D1 protein. The metagenome of the communities was used to produce clone libraries containing fragments of the psbA gene encoding the D1 protein. Community tolerance was quantified with a short-term test for the inhibition of photosynthesis. The communities were established in a continuous flow of natural seawater through microcosms with or without added Irgarol. The selection pressure from Irgarol resulted in an altered species composition and an inducted community tolerance to Irgarol. Moreover, there was a very high diversity in the psbA gene sequences in the periphyton, and the composition of psbA and D1 fragments within the communities was dramatically altered by increased Irgarol exposure. Even though tolerance to this type of compound in land plants often depends on a single amino acid substitution (Ser(264)-> Gly) in the D1 protein, this was not the case for marine periphyton species. Instead, the tolerance mechanism likely involves increased degradation of D1. When we compared sequences from low and high Irgarol exposure, differences in nonconserved amino acids were found only in the so-called PEST region of D1, which is involved in regulating its degradation. Our results suggest that environmental contamination with Irgarol has led to selection for high-turnover D1 proteins in marine periphyton communities at the west coast of Sweden.
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- Karlsson, Jan, 1956, et al.
(författare)
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Contribution to the seaweed flora of Sweden: New or otherwise interesting records from the west coast
- 1992
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Ingår i: Acta Phytogeographica Suecica. - 0084-5914. ; 78, s. 49-63
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Tidskriftsartikel (refereegranskat)abstract
- Records of attached seaweeds new to the flora of Sweden and records of very rare or otherwise interesting species from the west coast are presented with notes on their morphology, distribution and ecology. Platoma bairdii, Schmitzia hiscockiana, Sphaerococcus coronopifolius, Cryptopleura ramosa, Hypoglossum hypoglossoides, Delamarea attenuata, Sargassum muticum and Protomonostroma undulatum are additions to the flora recorded during the last twenty years. Twenty-four very rare or otherwise interesting species are also listed. Some species previously considered as rare, and some of the new finds, were found to be common. Proposed explanations for the increasing amount of records are: ( 1 ) methodological reasons (diving vs. dredging); (2) increased number of visits to wave-exposed habitats; (3) the occurrence of favourable years resulting in higher abundances. Several species are considered as genuinely rare in their entire geographical distribution area, while some have their present northern distribution boundary at the Swedish west coast.
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- Porsbring, Tobias, 1974, et al.
(författare)
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Effects of PSII inhibitors on the succession of natural marine microalgal communities is predictable by Concentration Addition
- 2009
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Ingår i: SETAC Europe 19th Annual Meeting, Gothenburg, Sweden.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Aquatic ecosystems are always exposed to chemical mixtures, and it is not sufficient to assess the risks of single chemicals one at a time. Concentration Addition (CA) has received much attention as a predictive tool to assess mixture toxicity. The accuracy of the concept for mixtures of similarly acting chemicals has been extensively demonstrated under relatively simple biological conditions with single species tests. Because ecosystems contain a high diversity of inter-connected species it is necessary to evaluate CA also on at least a community level of biological organisation. We sampled natural marine periphyton communities (attached microalgal and cyanobacterial communities) on glass discs submerged on the West coast of Sweden, and exposed them to toxicants over a 4 days ecological succession in the SWIFT periphyton test. The test medium consisted of filtered (GF/F) seawater with added PO42- and NO3- (0.7 and 8 micromol/L respectively) and was renewed daily. Multi- Dimensional Scaling was used to assess similarity in ecological mode of action between 2 different reference sets of PSII (photosystem II) inhibitors, on community species composition and pigment profiles. One mixture comprised phenylureas a priori determined as sharing a high similarity in mode of action. The other mixture comprised non-congeneric inhibitors of PSII (a phenylurea, an s-triazin and a uracil). The PSII inhibitors caused similar changes in species composition and pigment profiles, demonstrating that they shared a high similarity in ecological mode of action. CA accurately predicted the effects of both mixtures on pigment profiles. This demonstrates that CA has a high relevance on a community level, and is a justified approach to predict the joint risk from co-occurring inhibitors of PSII.
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| 6. |
- Porsbring, Tobias, 1974, et al.
(författare)
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Mixture toxicity from PSII inhibitors on microalgal community succession is predictable by Concentration Addition
- 2010
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Ingår i: Environmental Toxicology and Chemistry. - : Wiley. - 0730-7268. ; 29:12, s. 2806-2813
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Tidskriftsartikel (refereegranskat)abstract
- The typical pollution situation Involves chemical mixtures and assessing the risks of single chemicals one at a time is not sufficient Concentration addition (CA) has been suggested as a predictive tool in mixture ecotoxicology The accuracy of CA for mixtures of similarly acting chemicals has been demonstrated under relatively simple biological conditions in single species tests To consider the high diversity of interconnected species in ecosystems one must evaluate CA on a community level of biological organization We sampled marine periphyton communities from the west coast of Sweden and exposed them to photosystem II (PSII) inhibiting herbicides for 4 d in the SWIFT test a semistatic small-scale laboratory test During this time the communities went through an ecological succession influenced by the toxicants in a concentration dependent manner Multidimensional scaling was used to assess similarities in the effects of two different sets of PSII inhibitors on pigment profiles which reflects the taxonomic structure and the physiological status of the microalgal community One mixture of structurally congeneric phenylureas and one mixture of non congeneric PSII inhibitors were tested All PSII inhibitors and their mixtures caused similar changes in the pigment profiles demonstrating that they not only have a similar biochemical mechanism of action but also are similarly acting on a community level Concentration addition accurately predicted the effects of both mixtures over the entire effect range This demonstrates that chemical congenericity is not required for a high predictive power of CA Instead in perfect analogy to the situation in single species tests a similar mode of action is a sufficient prerequisite for a successful application of CA Environ Toxicol Chem 2010 29 2806-2813 (C) 2010 SETAC
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| 8. |
- Porsbring, Tobias, 1974, et al.
(författare)
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Observed and predicted combination effects of the antifouling agents irgarol 1051, TBT and Sea-Nine TM 211 on the structural and functional properties of marine microalgal communities
- 2004
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Ingår i: SETAC Europe 14th Annual meeting, Prague, Czech Republic.
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Konferensbidrag (refereegranskat)abstract
- Risks of mixtures of pollutants in ecosystems cannot be assessed when chemicals are treated as acting alone. This issue is increasingly recognised, but valid and useful tools for considering mixtures are needed. However the concepts Concentration Addition (CA) and Independent Action (IA) has been shown to have potential for predicting mixture toxicities. With the aim to evaluate CA and IA under ecologically realistic conditions the antifouling agents irgarol 1051, Sea-NineTM211 and TBT were tested singly and in an equieffective mixture on marine periphyton communities in a semistatic SWIFT test. Periphyton was established on 1.5 cm2 glass discs submerged in the Gullmar fjord, Sweden and then incubated for 96 h under constant light and temperature in a medium of GF/F filtered seawater with added phosphate, nitrate and toxicant(s). Effects were then quantified by comparing analysed pigment and species composition between treatments and controls using Bray-Curtis dissimilarity index. The observed mixture effect on species composition was in perfect agreement with CA, while IA was accurate for lower observed effects but overestimated the toxicity at higher. Using pigments for predictions was found to be sensitive as this reflected lower observed effects on species composition. IA and CA are beleived to apply for mixtures of toxicants with dissimilar and similar biochemical mechanisms of action respectively and as irgarol, TBT and Sea-Nine are dissimilarly acting the most accurate prediction should be IA. However biochemical modes of action may become less relevant for predictions in an ecological context where a mode of action could be defined more by impacts on specific species and trophic levels. Results indicates that risks of mixtures should be considered and are predictable.
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| 9. |
- Porsbring, Tobias, 1974, et al.
(författare)
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The SWIFT periphyton test for high-capacity assessments of toxicant effects on microalgal community development
- 2007
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Ingår i: Journal of Experimental Marine Biology and Ecology. - : Elsevier BV. - 0022-0981. ; 349:2, s. 299-312
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Tidskriftsartikel (refereegranskat)abstract
- The SWIFT periphyton test was developed as a simple and high-capacity approach for assessing toxicant effects on the succession of natural communities. Attached microbial communities (periphyton) were developed over a 7 to 9 day period on artificial glass substratum submerged at sea and then transferred to a controlled indoor environment for 4 day incubation with toxicants. Added nutrients and continuous light over the test phase facilitated periphyton growth and consequently accelerated the rate of ecological succession. The structure and physiology of the algal community can be analysed using any suitable method. In this paper we suggest HPLC-based analyses of community pigment profiles as a fast and less laborious alternative to e.g. microscopic species counts. Several crucial properties of the SWIFT test were evaluated: the biological complexity of the periphyton used for testing, the consequences of the 4 day incubation under artificial conditions, toxicant effects on community structure and the feasibility of using pigment profiles as descriptors of periphyton communities. The performance of SWIFT as an ecotoxicological test system was evaluated using the three antifouling agents irgarol 105 1, Sea-Nine(TM) 211 (DCOIT) and TBT (tri-n-butyltin). Periphyton communities used in SWIFT were of high taxonomic richness and diversity, and there were no indications for adverse changes in these characteristics over the 4 day test phase. Community pigment profiles discriminated between different communities with a resolution equally good to microscopic species counts. Comparative concentration-response studies with a two-week microcosm experiment and SWIFT revealed similar concentration and toxicant-dependent shifts in the relative abundances of species. This shows that despite the methodological simplifications in SWIFT, crucial ecological features such as competition and species sensitivity profiles were still the major factors determining the ecological succession under toxicant exposure. The sensitivity of SWIFT was equal to that of the flow-through microcosms for irgarol and TBT and lower for DCOIT, probably because of the semi-static test regime in SWIFT. Species composition and pigment profiles over seasons, together with toxicant-induced effects on the diatom xantophyll cycle and the relative content of beta-carotene, shows that pigment profiles reflect both the taxonomy and the physiology of a community. Similar to encountered changes in species composition, pigment profiles were specifically influenced by the tested toxicants. (C) 2007 Elsevier B.V. All rights reserved.
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