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S A Wangberg - One of the best experts on this subject based on the ideXlab platform.
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influence of trace metal release from volcanic ash on growth of Thalassiosira pseudonana and emiliania huxleyi
Marine Chemistry, 2012Co-Authors: Linn Hoffmann, Eike Breitbarth, Murat Van Ardelan, Svend Duggen, Nazli Olgun, Martin Hassellov, S A WangbergAbstract:Recent studies demonstrate that volcanic ash has the potential to increase phytoplankton biomass in the open ocean. However, besides fertilizing trace metals such as Fe, volcanic ash contains a variety of potentially toxic metals such as Cd, Cu, Pb, and Zn. Especially in coastal regions closer to the volcanic eruption, where ash depositions can be very high, toxic effects are possible. Here we present the first results from laboratory experiments, showing that trace metal release from different volcanic ashes can have both fertilizing and toxic effects on marine phytoplankton in natural coastal seawater. The diatom Thalassiosira pseudonana generally showed higher growth rates in seawater that was in short contact with volcanic ash compared to the controls without ash addition. In contrast to that, the addition of volcanic ash had either no effect or significantly decreased the growth rate of the coccolithophoride Emiliania huxleyi. It was not possible to attribute the effects to single trace metals, however, our results suggest that Mn plays an important role in regulating the antagonistic and synergistic effects of the different trace metals. This study shows that volcanic ash can lead to changes in the phytoplankton species composition in the high fall-out area of the surface ocean.
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influence of trace metal release from volcanic ash on growth of Thalassiosira pseudonana and emiliania huxleyi
Marine Chemistry, 2012Co-Authors: Eike Breitbarth, Murat Van Ardelan, Svend Duggen, Nazli Olgun, Martin Hassellov, Linn J Hoffmann, S A WangbergAbstract:Recent studies demonstrate that volcanic ash has the potential to increase phytoplankton biomass in the open ocean. However, besides fertilizing trace metals such as Fe, volcanic ash contains a variety of potentially toxic metals such as Cd, Cu, Pb, and Zn. Especially in coastal regions closer to the volcanic eruption, where ash depositions can be very high, toxic effects are possible. Here we present the first results of laboratory experiments, showing that trace metal release from different volcanic materials can have both fertilizing and toxic effects on marine phytoplankton in natural coastal seawater. The diatom Thalassiosira pseudonana generally showed higher growth rates in seawater that was in short contact with volcanic ash compared to the controls without ash addition. In contrast to that, the addition of volcanic ash had either no effect or significantly decreased the growth rate of the coccolithophoride Emiliania huxleyi. It was not possible to attribute the effects to single trace metals, however, our results suggest that Mn plays an important role in regulating the antagonistic and synergistic effects of the different trace metals. This study shows that volcanic ash can lead to changes in the phytoplankton species composition in the high fall-out area of the surface ocean. Highlights: ► We tested the effect of volcanic ash on growth of T. pseudonana and E. huxleyi ► Volcanic ash increased growth of T. pseudonana but not of E. huxleyi ► Mn seems important to regulate the effects of different trace metals from the ash ► Volcanic eruptions have the potential to change phytoplankton community structures
Eike Breitbarth - One of the best experts on this subject based on the ideXlab platform.
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influence of trace metal release from volcanic ash on growth of Thalassiosira pseudonana and emiliania huxleyi
Marine Chemistry, 2012Co-Authors: Linn Hoffmann, Eike Breitbarth, Murat Van Ardelan, Svend Duggen, Nazli Olgun, Martin Hassellov, S A WangbergAbstract:Recent studies demonstrate that volcanic ash has the potential to increase phytoplankton biomass in the open ocean. However, besides fertilizing trace metals such as Fe, volcanic ash contains a variety of potentially toxic metals such as Cd, Cu, Pb, and Zn. Especially in coastal regions closer to the volcanic eruption, where ash depositions can be very high, toxic effects are possible. Here we present the first results from laboratory experiments, showing that trace metal release from different volcanic ashes can have both fertilizing and toxic effects on marine phytoplankton in natural coastal seawater. The diatom Thalassiosira pseudonana generally showed higher growth rates in seawater that was in short contact with volcanic ash compared to the controls without ash addition. In contrast to that, the addition of volcanic ash had either no effect or significantly decreased the growth rate of the coccolithophoride Emiliania huxleyi. It was not possible to attribute the effects to single trace metals, however, our results suggest that Mn plays an important role in regulating the antagonistic and synergistic effects of the different trace metals. This study shows that volcanic ash can lead to changes in the phytoplankton species composition in the high fall-out area of the surface ocean.
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influence of trace metal release from volcanic ash on growth of Thalassiosira pseudonana and emiliania huxleyi
Marine Chemistry, 2012Co-Authors: Eike Breitbarth, Murat Van Ardelan, Svend Duggen, Nazli Olgun, Martin Hassellov, Linn J Hoffmann, S A WangbergAbstract:Recent studies demonstrate that volcanic ash has the potential to increase phytoplankton biomass in the open ocean. However, besides fertilizing trace metals such as Fe, volcanic ash contains a variety of potentially toxic metals such as Cd, Cu, Pb, and Zn. Especially in coastal regions closer to the volcanic eruption, where ash depositions can be very high, toxic effects are possible. Here we present the first results of laboratory experiments, showing that trace metal release from different volcanic materials can have both fertilizing and toxic effects on marine phytoplankton in natural coastal seawater. The diatom Thalassiosira pseudonana generally showed higher growth rates in seawater that was in short contact with volcanic ash compared to the controls without ash addition. In contrast to that, the addition of volcanic ash had either no effect or significantly decreased the growth rate of the coccolithophoride Emiliania huxleyi. It was not possible to attribute the effects to single trace metals, however, our results suggest that Mn plays an important role in regulating the antagonistic and synergistic effects of the different trace metals. This study shows that volcanic ash can lead to changes in the phytoplankton species composition in the high fall-out area of the surface ocean. Highlights: ► We tested the effect of volcanic ash on growth of T. pseudonana and E. huxleyi ► Volcanic ash increased growth of T. pseudonana but not of E. huxleyi ► Mn seems important to regulate the effects of different trace metals from the ash ► Volcanic eruptions have the potential to change phytoplankton community structures
Teresa Lettieri - One of the best experts on this subject based on the ideXlab platform.
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detection of silver nanoparticles inside marine diatom Thalassiosira pseudonana by electron microscopy and focused ion beam
PLOS ONE, 2014Co-Authors: Cesar Pascual Garcia, Alina D Burchardt, Raquel N Carvalho, Douglas Gilliland, Francois Rossi, Diana C Antonio, Teresa LettieriAbstract:In the following article an electron/ion microscopy study will be presented which investigates the uptake of silver nanoparticles (AgNPs) by the marine diatom Thalassiosira pseudonana, a primary producer aquatic species. This organism has a characteristic silica exoskeleton that may represent a barrier for the uptake of some chemical pollutants, including nanoparticles (NPs), but that presents a technical challenge when attempting to use electron-microscopy (EM) methods to study NP uptake. Here we present a convenient method to detect the NPs interacting with the diatom cell. It is based on a fixation procedure involving critical point drying which, without prior slicing of the cell, allows its inspection using transmission electron microscopy. Employing a combination of electron and ion microscopy techniques to selectively cut the cell where the NPs were detected, we are able to demonstrate and visualize for the first time the presence of AgNPs inside the cell membrane.
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effects of silver nanoparticles in diatom Thalassiosira pseudonana and cyanobacterium synechococcus sp
Environmental Science & Technology, 2012Co-Authors: Alina D Burchardt, Raquel N Carvalho, Angelica Valente, Paola Nativo, Douglas Gilliland, Cesar Pascual Garcia, Rosanna Passarella, Valerio Pedroni, Francois Rossi, Teresa LettieriAbstract:The aim of the present study was to investigate the effect of silver nanoparticles (AgNP) of different sizes toward two primary producer aquatic species. Thalassiosira pseudonana and Synechococcus sp. have been selected as representative models for the lower trophic organisms in marine and freshwater habitats, respectively. Time-dependent cellular growth was measured upon exposure to both AgNP and silver nitrate (AgNO3). In addition, AgNP behavior in freshwater and marine waters has been followed by CPS disc centrifuge, in the time frame of AgNP exposure studies, and the kinetic release of silver from AgNP of different sizes was measured by dialysis and inductively coupled plasma mass spectrometry (ICP-MS). The combination and interpretation of all these data suggest that a shared effect of AgNP and released silver was responsible for the toxicity in both organisms. Furthermore, the toxic effects induced by AgNP exposure in the present study seem to result from a mixture of parameters including aggregated...
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transcriptomics responses in marine diatom Thalassiosira pseudonana exposed to the polycyclic aromatic hydrocarbon benzo a pyrene
PLOS ONE, 2011Co-Authors: Raquel N Carvalho, Stephanie K Bopp, Teresa LettieriAbstract:Diatoms are unicellular, photosynthetic, eukaryotic algae with a ubiquitous distribution in water environments and they play an important role in the carbon cycle. Molecular or morphological changes in these species under ecological stress conditions are expected to serve as early indicators of toxicity and can point to a global impact on the entire ecosystem. Thalassiosira pseudonana, a marine diatom and the first with a fully sequenced genome has been selected as an aquatic model organism for ecotoxicological studies using molecular tools. A customized DNA microarray containing probes for the available gene sequences has been developed and tested to analyze the effects of a common pollutant, benzo(a)pyrene (BaP), at a sub-lethal concentration. This approach in diatoms has helped to elucidate pathway/metabolic processes involved in the mode of action of this pollutant, including lipid metabolism, silicon metabolism and stress response. A dose-response of BaP on diatoms has been made and the effect of this compound on the expression of selected genes was assessed by quantitative real time-PCR. Up-regulation of the long-chain acyl-CoA synthetase and the anti-apoptotic transmembrane Bax inhibitor, as well as down-regulation of silicon transporter 1 and a heat shock factor was confirmed at lower concentrations of BaP, but not the heat-shock protein 20. The study has allowed the identification of molecular biomarkers to BaP to be later on integrated into environmental monitoring for water quality assessment.
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proteomic analysis of the marine diatom Thalassiosira pseudonana upon exposure to benzo a pyrene
BMC Genomics, 2011Co-Authors: Raquel N Carvalho, Teresa LettieriAbstract:Polycyclic aromatic hydrocarbons (PAHs) are environmental pollutants ubiquitously distributed. They are generated by incomplete combustion of organic materials such as wood or fossil fuels. Due to their carcinogenic, mutagenic effects and to their wide distribution in the environment, these pollutants pose many concerns to researchers and regulators. In our laboratories we investigated the effect of benzo(a)pyrene (BaP) exposure in the marine diatom Thalassiosira pseudonana, which has become an important model organism in aquatic toxicology studies. In order to investigate the mechanism of action of PAHs, we exposed the diatoms for 24 h to 36.45 μg/L of BaP which inhibits the growth by about 30%, and analysed the relative protein expression profile by a quantitative proteomics approach based on iTRAQ labels. The proteomics profile analysis showed that around 10% of the identified proteins were regulated and one fourth of them confirmed the gene expression changes seen by DNA microarray. Particularly interesting was the down regulation of the Silicon transporter 1 (SIT1), an enzyme that is responsible for the uptake of silicon from the media into the diatom cells. Regulation of SIT1 upon BaP treatment was also confirmed at the gene expression level. The potential use of the regulated proteins found in this study as early indicators of environmental exposure to PAHs is discussed. In particular, SIT1 is considered a promising biomarker and SIT1 expression changes were confirmed also when the diatoms were exposed to field samples, e.g. marine surface sediments contaminated by PAHs.
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gene biomarkers in diatom Thalassiosira pseudonana exposed to polycyclic aromatic hydrocarbons from contaminated marine surface sediments
Aquatic Toxicology, 2011Co-Authors: Raquel N Carvalho, Alina D Burchardt, Stephanie K Bopp, Fabrizio Sena, Giulio Mariani, Anne Mueller, Gunther Umlauf, Teresa LettieriAbstract:Marine diatoms have a key role in the global carbon fixation and therefore in the ecosystem. We used Thalassiosira pseudonana as a model organism to assess the effects of exposure to environmental pollutants at the gene expression level. Diatoms were exposed to polycyclic aromatic hydrocarbons mixture (PAH) from surface sediments collected at a highly PAH contaminated area of the Mediterranean Sea (Genoa, Italy), due to intense industrial and harbor activities. The gene expression data for exposure to the sediment-derived PAH mixture was compared with gene expression data for in vitro exposure to specific polycyclic aromatic hydrocarbons. The data shows that genes involved in stress response, silica uptake, and metabolism were regulated both upon exposure to the sediment-derived PAH mixture and to the single component. Complementary monitoring of silica in the diatom cultures provide further evidence of a reduced cellular uptake of silica as an end-point for benzo[a]pyrene exposure that could be linked with the reduced gene and protein expression of the silicon transporter protein. However some genes showed differences in regulation indicating that mixtures of structurally related chemical compounds can elicit a slightly different gene expression response compared to that of a single component. The paper provides indications on the specific pathways affected by PAH exposure and shows that selected genes (silicon transporter, and silaffin 3) involved in silica uptake and metabolism could be suitable molecular biomarkers of exposure to PAHs.
Linn J Hoffmann - One of the best experts on this subject based on the ideXlab platform.
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influence of trace metal release from volcanic ash on growth of Thalassiosira pseudonana and emiliania huxleyi
Marine Chemistry, 2012Co-Authors: Eike Breitbarth, Murat Van Ardelan, Svend Duggen, Nazli Olgun, Martin Hassellov, Linn J Hoffmann, S A WangbergAbstract:Recent studies demonstrate that volcanic ash has the potential to increase phytoplankton biomass in the open ocean. However, besides fertilizing trace metals such as Fe, volcanic ash contains a variety of potentially toxic metals such as Cd, Cu, Pb, and Zn. Especially in coastal regions closer to the volcanic eruption, where ash depositions can be very high, toxic effects are possible. Here we present the first results of laboratory experiments, showing that trace metal release from different volcanic materials can have both fertilizing and toxic effects on marine phytoplankton in natural coastal seawater. The diatom Thalassiosira pseudonana generally showed higher growth rates in seawater that was in short contact with volcanic ash compared to the controls without ash addition. In contrast to that, the addition of volcanic ash had either no effect or significantly decreased the growth rate of the coccolithophoride Emiliania huxleyi. It was not possible to attribute the effects to single trace metals, however, our results suggest that Mn plays an important role in regulating the antagonistic and synergistic effects of the different trace metals. This study shows that volcanic ash can lead to changes in the phytoplankton species composition in the high fall-out area of the surface ocean. Highlights: ► We tested the effect of volcanic ash on growth of T. pseudonana and E. huxleyi ► Volcanic ash increased growth of T. pseudonana but not of E. huxleyi ► Mn seems important to regulate the effects of different trace metals from the ash ► Volcanic eruptions have the potential to change phytoplankton community structures
Linn Hoffmann - One of the best experts on this subject based on the ideXlab platform.
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influence of trace metal release from volcanic ash on growth of Thalassiosira pseudonana and emiliania huxleyi
Marine Chemistry, 2012Co-Authors: Linn Hoffmann, Eike Breitbarth, Murat Van Ardelan, Svend Duggen, Nazli Olgun, Martin Hassellov, S A WangbergAbstract:Recent studies demonstrate that volcanic ash has the potential to increase phytoplankton biomass in the open ocean. However, besides fertilizing trace metals such as Fe, volcanic ash contains a variety of potentially toxic metals such as Cd, Cu, Pb, and Zn. Especially in coastal regions closer to the volcanic eruption, where ash depositions can be very high, toxic effects are possible. Here we present the first results from laboratory experiments, showing that trace metal release from different volcanic ashes can have both fertilizing and toxic effects on marine phytoplankton in natural coastal seawater. The diatom Thalassiosira pseudonana generally showed higher growth rates in seawater that was in short contact with volcanic ash compared to the controls without ash addition. In contrast to that, the addition of volcanic ash had either no effect or significantly decreased the growth rate of the coccolithophoride Emiliania huxleyi. It was not possible to attribute the effects to single trace metals, however, our results suggest that Mn plays an important role in regulating the antagonistic and synergistic effects of the different trace metals. This study shows that volcanic ash can lead to changes in the phytoplankton species composition in the high fall-out area of the surface ocean.