The Experts below are selected from a list of 5553 Experts worldwide ranked by ideXlab platform
Fernanda Cassio - One of the best experts on this subject based on the ideXlab platform.
-
taxa area relationship of Aquatic Fungi on deciduous leaves
PLOS ONE, 2017Co-Authors: Sofia Alexandra Ferreira Duarte, Claudia Pascoal, Fernanda Cassio, Felix BärlocherAbstract:One of the fundamental patterns in macroecology is the increase in the number of observed taxa with size of sampled area. For microbes, the shape of this relationship remains less clear. The current study assessed the diversity of Aquatic Fungi, by the traditional approach based on conidial morphology (captures reproducing Aquatic hyphomycetes) and next generation sequencing (NGS; captures other Fungi as well), on graded sizes of alder leaves (0.6 to 13.6 cm2). Leaves were submerged in two streams in geographically distant locations: the Oliveira Stream in Portugal and the Boss Brook in Canada. Decay rates of alder leaves and fungal sporulation rates did not differ between streams. Fungal biomass was higher in Boss Brook than in Oliveira Stream, and in both streams almost 100% of the reads belonged to active fungal taxa. In general, larger leaf areas tended to harbour more Fungi, but these findings were not consistent between techniques. Morphospecies-based diversity increased with leaf area in Boss Brook, but not in Oliveira Stream; metabarcoding data showed an opposite trend. The higher resolution of metabarcoding resulted in steeper taxa-accumulation curves than morphospecies-based assessments (fungal conidia morphology). Fungal communities assessed by metabarcoding were spatially structured by leaf area in both streams. Metabarcoding promises greater resolution to assess biodiversity patterns in Aquatic Fungi and may be more accurate for assessing taxa-area relationships and local to global diversity ratios.
-
copper and zinc affect the activity of plasma membrane h atpase and thiol content in Aquatic Fungi
Microbiology, 2016Co-Authors: Claudia Pascoal, Maria Manuel Azevedo, Luis Guimaraessoares, Fernanda CassioAbstract:Aquatic hyphomycetes are the major microbial decomposers of plant litter in streams. We selected three Aquatic hyphomycete species with different abilities to tolerate, adsorb and accumulate copper and zinc, and we investigated the effects of these metals on H+-ATPase activity as well as on the levels of thiol (SH)-containing compounds. Before metal exposure, the species isolated from a metal-polluted stream (Heliscus submersus and Flagellospora curta) had higher levels of thiol compounds than the species isolated from a clean stream (Varicosporium elodeae). However, V. elodeae rapidly increased the levels of thiols after metal exposure, emphasizing the importance of these compounds in fungal survival under metal stress. The highest amounts of metals adsorbed to fungal mycelia were found in the most tolerant species to each metal, i.e. in H. submersus exposed to copper and in V. elodeae exposed to zinc. Short-term (10 min) exposure to copper completely inhibited the activity of H+-ATPase of H. submersus and V. elodeae, whilst zinc only led to a similar effect on H. submersus. However, at longer exposure times (8 days) the most metal-tolerant species exhibited increased H+-ATPase activities, suggesting that the plasma membrane proton pump may be involved in the acclimation of Aquatic hyphomycetes to metals.
-
temperature alters interspecific relationships among Aquatic Fungi
Fungal Ecology, 2013Co-Authors: Sofia Alexandra Ferreira Duarte, Fernanda Cassio, Isabel Rodrigues Fernandes, Maria Joao Nogueira, Claudia PascoalAbstract:Temperature is a key factor in determining the structure and performance of fungal assemblages on decomposing plant litter in streams. However, little is known of how temperature affects interspecific relationships among Fungi. We compared the growth of four Aquatic hyphomycetes co-occurring in temperate streams, in monocultures and all species combinations when exposed to five temperatures from 11 to 27 °C. In monocultures, maximum growth rates of Heliscus submersus, Lunulospora curvula and Varicosporium elodeae occurred at 27 °C whereas Articulospora tetracladia had the lowest growth rate. At 27 °C, the increase in species diversity had no effect on the growth of V. elodeae, increased the growth of H. submersus and L. curvula, and decreased the growth of A. tetracladia. Results suggest that within a species' optimal temperature range the growth of that species increases with higher fungal diversity, while outside this range growth decreases with diversity.
-
higher temperature reduces the effects of litter quality on decomposition by Aquatic Fungi
Freshwater Biology, 2012Co-Authors: Isabel Rodrigues Fernandes, Claudia Pascoal, Helena Guimaraes, Rute Pinto, Ines Sousa, Fernanda CassioAbstract:The Portuguese Foundation for Science and Technology - PTDC⁄CLI⁄67180⁄2006, PTDC⁄AAC-AMB⁄117068⁄2010, PEst-C⁄BIA⁄UI4050⁄2011, SFRH⁄BD⁄42215⁄2007
-
effects of cadmium and phenanthrene mixtures on Aquatic Fungi and microbially mediated leaf litter decomposition
Archives of Environmental Contamination and Toxicology, 2011Co-Authors: Catarina Moreirinha, Sofia Alexandra Ferreira Duarte, Claudia Pascoal, Fernanda CassioAbstract:Urbanization and industrial activities have contributed to widespread contamination by metals and polycyclic aromatic hydrocarbons, but the combined effects of these toxics on Aquatic biota and processes are poorly understood. We examined the effects of cadmium (Cd) and phenanthrene on the activity and diversity of Fungi associated with decomposing leaf litter in streams. Leaves of Alnus glutinosa were immersed for 10 days in an unpolluted low-order stream in northwest Portugal to allow microbial colonization. Leaves were then exposed in microcosms for 14 days to Cd (0.06–4.5 mg L−1) and phenanthrene (0.2 mg L−1) either alone or in mixture. A total of 19 Aquatic hyphomycete species were found sporulating on leaves during the whole study. The dominant species was Articulospora tetracladia, followed by Alatospora pulchella,Clavatospora longibrachiata, and Tetrachaetum elegans. Exposure to Cd and phenanthrene decreased the contribution of A. tetracladia to the total conidial production, whereas it increased that of A. pulchella. Fungal diversity, assessed as denaturing gradient gel electrophoresis fingerprinting or conidial morphology, was decreased by the exposure to Cd and/or phenanthrene. Moreover, increased Cd concentrations decreased leaf decomposition and fungal reproduction but did not inhibit fungal biomass production. Exposure to phenanthrene potentiated the negative effects of Cd on fungal diversity and activity, suggesting that the co-occurrence of these stressors may pose additional risk to Aquatic biodiversity and stream ecosystem functioning.
Claudia Pascoal - One of the best experts on this subject based on the ideXlab platform.
-
taxa area relationship of Aquatic Fungi on deciduous leaves
PLOS ONE, 2017Co-Authors: Sofia Alexandra Ferreira Duarte, Claudia Pascoal, Fernanda Cassio, Felix BärlocherAbstract:One of the fundamental patterns in macroecology is the increase in the number of observed taxa with size of sampled area. For microbes, the shape of this relationship remains less clear. The current study assessed the diversity of Aquatic Fungi, by the traditional approach based on conidial morphology (captures reproducing Aquatic hyphomycetes) and next generation sequencing (NGS; captures other Fungi as well), on graded sizes of alder leaves (0.6 to 13.6 cm2). Leaves were submerged in two streams in geographically distant locations: the Oliveira Stream in Portugal and the Boss Brook in Canada. Decay rates of alder leaves and fungal sporulation rates did not differ between streams. Fungal biomass was higher in Boss Brook than in Oliveira Stream, and in both streams almost 100% of the reads belonged to active fungal taxa. In general, larger leaf areas tended to harbour more Fungi, but these findings were not consistent between techniques. Morphospecies-based diversity increased with leaf area in Boss Brook, but not in Oliveira Stream; metabarcoding data showed an opposite trend. The higher resolution of metabarcoding resulted in steeper taxa-accumulation curves than morphospecies-based assessments (fungal conidia morphology). Fungal communities assessed by metabarcoding were spatially structured by leaf area in both streams. Metabarcoding promises greater resolution to assess biodiversity patterns in Aquatic Fungi and may be more accurate for assessing taxa-area relationships and local to global diversity ratios.
-
copper and zinc affect the activity of plasma membrane h atpase and thiol content in Aquatic Fungi
Microbiology, 2016Co-Authors: Claudia Pascoal, Maria Manuel Azevedo, Luis Guimaraessoares, Fernanda CassioAbstract:Aquatic hyphomycetes are the major microbial decomposers of plant litter in streams. We selected three Aquatic hyphomycete species with different abilities to tolerate, adsorb and accumulate copper and zinc, and we investigated the effects of these metals on H+-ATPase activity as well as on the levels of thiol (SH)-containing compounds. Before metal exposure, the species isolated from a metal-polluted stream (Heliscus submersus and Flagellospora curta) had higher levels of thiol compounds than the species isolated from a clean stream (Varicosporium elodeae). However, V. elodeae rapidly increased the levels of thiols after metal exposure, emphasizing the importance of these compounds in fungal survival under metal stress. The highest amounts of metals adsorbed to fungal mycelia were found in the most tolerant species to each metal, i.e. in H. submersus exposed to copper and in V. elodeae exposed to zinc. Short-term (10 min) exposure to copper completely inhibited the activity of H+-ATPase of H. submersus and V. elodeae, whilst zinc only led to a similar effect on H. submersus. However, at longer exposure times (8 days) the most metal-tolerant species exhibited increased H+-ATPase activities, suggesting that the plasma membrane proton pump may be involved in the acclimation of Aquatic hyphomycetes to metals.
-
temperature alters interspecific relationships among Aquatic Fungi
Fungal Ecology, 2013Co-Authors: Sofia Alexandra Ferreira Duarte, Fernanda Cassio, Isabel Rodrigues Fernandes, Maria Joao Nogueira, Claudia PascoalAbstract:Temperature is a key factor in determining the structure and performance of fungal assemblages on decomposing plant litter in streams. However, little is known of how temperature affects interspecific relationships among Fungi. We compared the growth of four Aquatic hyphomycetes co-occurring in temperate streams, in monocultures and all species combinations when exposed to five temperatures from 11 to 27 °C. In monocultures, maximum growth rates of Heliscus submersus, Lunulospora curvula and Varicosporium elodeae occurred at 27 °C whereas Articulospora tetracladia had the lowest growth rate. At 27 °C, the increase in species diversity had no effect on the growth of V. elodeae, increased the growth of H. submersus and L. curvula, and decreased the growth of A. tetracladia. Results suggest that within a species' optimal temperature range the growth of that species increases with higher fungal diversity, while outside this range growth decreases with diversity.
-
higher temperature reduces the effects of litter quality on decomposition by Aquatic Fungi
Freshwater Biology, 2012Co-Authors: Isabel Rodrigues Fernandes, Claudia Pascoal, Helena Guimaraes, Rute Pinto, Ines Sousa, Fernanda CassioAbstract:The Portuguese Foundation for Science and Technology - PTDC⁄CLI⁄67180⁄2006, PTDC⁄AAC-AMB⁄117068⁄2010, PEst-C⁄BIA⁄UI4050⁄2011, SFRH⁄BD⁄42215⁄2007
-
effects of cadmium and phenanthrene mixtures on Aquatic Fungi and microbially mediated leaf litter decomposition
Archives of Environmental Contamination and Toxicology, 2011Co-Authors: Catarina Moreirinha, Sofia Alexandra Ferreira Duarte, Claudia Pascoal, Fernanda CassioAbstract:Urbanization and industrial activities have contributed to widespread contamination by metals and polycyclic aromatic hydrocarbons, but the combined effects of these toxics on Aquatic biota and processes are poorly understood. We examined the effects of cadmium (Cd) and phenanthrene on the activity and diversity of Fungi associated with decomposing leaf litter in streams. Leaves of Alnus glutinosa were immersed for 10 days in an unpolluted low-order stream in northwest Portugal to allow microbial colonization. Leaves were then exposed in microcosms for 14 days to Cd (0.06–4.5 mg L−1) and phenanthrene (0.2 mg L−1) either alone or in mixture. A total of 19 Aquatic hyphomycete species were found sporulating on leaves during the whole study. The dominant species was Articulospora tetracladia, followed by Alatospora pulchella,Clavatospora longibrachiata, and Tetrachaetum elegans. Exposure to Cd and phenanthrene decreased the contribution of A. tetracladia to the total conidial production, whereas it increased that of A. pulchella. Fungal diversity, assessed as denaturing gradient gel electrophoresis fingerprinting or conidial morphology, was decreased by the exposure to Cd and/or phenanthrene. Moreover, increased Cd concentrations decreased leaf decomposition and fungal reproduction but did not inhibit fungal biomass production. Exposure to phenanthrene potentiated the negative effects of Cd on fungal diversity and activity, suggesting that the co-occurrence of these stressors may pose additional risk to Aquatic biodiversity and stream ecosystem functioning.
Eric Chauvet - One of the best experts on this subject based on the ideXlab platform.
-
Allelopathic inhibition of primary producer growth and photosynthesis by Aquatic Fungi
Fungal Ecology, 2017Co-Authors: Joey Allen, Julien Cornut, Eric Chauvet, Joséphine Leflaive, Charlotte Bringuier, Loïc Ten-hage, Michael DangerAbstract:Autochthonous primary production is generally much reduced in forested headwater streams. Several hypotheses have been proposed for explaining this observation, among them, the low light intensity, or the strong constraints exerted by stream current. Allelopathic inhibition of competitors is a common ecological process in Aquatic environments. Aquatic hyphomycetes are known to chemically inhibit bacteria and other Fungi (including other Aquatic hyphomycetes) but a possible allelopathic effect of Aquatic hyphomycetes on primary producers has never been tested. The inhibitory effect of twelve Aquatic hyphomycete species was tested on three diatom species. Nine Aquatic hyphomycete species exhibited anti-diatom activity. Up to 100% diatom growth inhibition was observed. Our study reveals that such allelopathic interactions might be common in streams and probably involve an array of fungal compounds. We propose that the generally reduced primary production observed in forested headwater streams is, among other factors, due to the inhibition of primary producers by allelopathic compounds released by Aquatic hyphomycetes.
-
early stages of leaf decomposition are mediated by Aquatic Fungi in the hyporheic zone of woodland streams
Freshwater Biology, 2010Co-Authors: Pierre Marmonier, Julien Cornut, Arnaud Elger, Didier Lambrigot, Eric ChauvetAbstract:SUMMARY 1. Leaf litter constitutes the major source of organic matter and energy in woodland stream ecosystems. A substantial part of leaf litter entering running waters may be buried in the streambed as a consequence of flooding and sediment movement. While decomposition of leaf litter in surface waters is relatively well understood, its fate when incorporated into river sediments, as well as the involvement of invertebrate and fungal decomposers in such conditions, remain poorly documented. 2. We tested experimentally the hypotheses that the small interstices of the sediment restrict the access of the largest shredders to buried organic matter without compromising that of Aquatic hyphomycetes and that fungal decomposers in the hyporheic zone, at least partly, compensate for the role of invertebrate detritivores in the benthic zone. 3. Alder leaves were introduced in a stream either buried in the sediment (hyporheic), buried after 2 weeks of exposure at the sediment surface (benthic-hyporheic), or exposed at the sediment surface for the entire experiment (benthic). Leaf decomposition was markedly faster on the streambed surface than in the two other treatments (2.1- and 2.8-fold faster than in the benthic-hyporheic and hyporheic treatments, respectively). 4. Fungal assemblages were generally less diverse in the hyporheic habitat with a few species tending to be relatively favoured by such conditions. Both fungal biomass and sporulation rates were reduced in the hyporheic treatment, with the leaves subject to the benthic-hyporheic treatment exhibiting an intermediate pattern. The initial 2-week stage in the benthic habitat shaped the fungal assemblages, even for leaves later subjected to the hyporheic conditions. 5. The abundance and biomass of shredders drastically decreased with burial, except for Leuctra spp., which increased and was by far the most common leaf-associated taxon in the hyporheic zone. Leuctra spp. was one of the rare shredder taxa displaying morphological characteristics that increased performance within the limited space of sediment interstices. 6. The carbon budgets indicated that the relative contributions of the two main decomposers, shredders and Fungi, varied considerably depending on the location within the streambed. While the shredder biomass represented almost 50% of the initial carbon transformed after 80 days in the benthic treatment, its contribution was <0.3% in the hyporheic one and 2.0% in the combined benthic-hyporheic treatment. In contrast,
Sofia Alexandra Ferreira Duarte - One of the best experts on this subject based on the ideXlab platform.
-
taxa area relationship of Aquatic Fungi on deciduous leaves
PLOS ONE, 2017Co-Authors: Sofia Alexandra Ferreira Duarte, Claudia Pascoal, Fernanda Cassio, Felix BärlocherAbstract:One of the fundamental patterns in macroecology is the increase in the number of observed taxa with size of sampled area. For microbes, the shape of this relationship remains less clear. The current study assessed the diversity of Aquatic Fungi, by the traditional approach based on conidial morphology (captures reproducing Aquatic hyphomycetes) and next generation sequencing (NGS; captures other Fungi as well), on graded sizes of alder leaves (0.6 to 13.6 cm2). Leaves were submerged in two streams in geographically distant locations: the Oliveira Stream in Portugal and the Boss Brook in Canada. Decay rates of alder leaves and fungal sporulation rates did not differ between streams. Fungal biomass was higher in Boss Brook than in Oliveira Stream, and in both streams almost 100% of the reads belonged to active fungal taxa. In general, larger leaf areas tended to harbour more Fungi, but these findings were not consistent between techniques. Morphospecies-based diversity increased with leaf area in Boss Brook, but not in Oliveira Stream; metabarcoding data showed an opposite trend. The higher resolution of metabarcoding resulted in steeper taxa-accumulation curves than morphospecies-based assessments (fungal conidia morphology). Fungal communities assessed by metabarcoding were spatially structured by leaf area in both streams. Metabarcoding promises greater resolution to assess biodiversity patterns in Aquatic Fungi and may be more accurate for assessing taxa-area relationships and local to global diversity ratios.
-
temperature alters interspecific relationships among Aquatic Fungi
Fungal Ecology, 2013Co-Authors: Sofia Alexandra Ferreira Duarte, Fernanda Cassio, Isabel Rodrigues Fernandes, Maria Joao Nogueira, Claudia PascoalAbstract:Temperature is a key factor in determining the structure and performance of fungal assemblages on decomposing plant litter in streams. However, little is known of how temperature affects interspecific relationships among Fungi. We compared the growth of four Aquatic hyphomycetes co-occurring in temperate streams, in monocultures and all species combinations when exposed to five temperatures from 11 to 27 °C. In monocultures, maximum growth rates of Heliscus submersus, Lunulospora curvula and Varicosporium elodeae occurred at 27 °C whereas Articulospora tetracladia had the lowest growth rate. At 27 °C, the increase in species diversity had no effect on the growth of V. elodeae, increased the growth of H. submersus and L. curvula, and decreased the growth of A. tetracladia. Results suggest that within a species' optimal temperature range the growth of that species increases with higher fungal diversity, while outside this range growth decreases with diversity.
-
effects of cadmium and phenanthrene mixtures on Aquatic Fungi and microbially mediated leaf litter decomposition
Archives of Environmental Contamination and Toxicology, 2011Co-Authors: Catarina Moreirinha, Sofia Alexandra Ferreira Duarte, Claudia Pascoal, Fernanda CassioAbstract:Urbanization and industrial activities have contributed to widespread contamination by metals and polycyclic aromatic hydrocarbons, but the combined effects of these toxics on Aquatic biota and processes are poorly understood. We examined the effects of cadmium (Cd) and phenanthrene on the activity and diversity of Fungi associated with decomposing leaf litter in streams. Leaves of Alnus glutinosa were immersed for 10 days in an unpolluted low-order stream in northwest Portugal to allow microbial colonization. Leaves were then exposed in microcosms for 14 days to Cd (0.06–4.5 mg L−1) and phenanthrene (0.2 mg L−1) either alone or in mixture. A total of 19 Aquatic hyphomycete species were found sporulating on leaves during the whole study. The dominant species was Articulospora tetracladia, followed by Alatospora pulchella,Clavatospora longibrachiata, and Tetrachaetum elegans. Exposure to Cd and phenanthrene decreased the contribution of A. tetracladia to the total conidial production, whereas it increased that of A. pulchella. Fungal diversity, assessed as denaturing gradient gel electrophoresis fingerprinting or conidial morphology, was decreased by the exposure to Cd and/or phenanthrene. Moreover, increased Cd concentrations decreased leaf decomposition and fungal reproduction but did not inhibit fungal biomass production. Exposure to phenanthrene potentiated the negative effects of Cd on fungal diversity and activity, suggesting that the co-occurrence of these stressors may pose additional risk to Aquatic biodiversity and stream ecosystem functioning.
-
effects of zn fe and mn on leaf litter breakdown by Aquatic Fungi a microcosm study
International Review of Hydrobiology, 2010Co-Authors: Adriana O Medeiros, Sofia Alexandra Ferreira Duarte, Claudia Pascoal, Fernanda Cassio, Manuel A S GracaAbstract:We investigated the effects of heavy metals on leaf litter decomposition in streams. Leaves were immersed (10 days) at a reference (R) and a metal-impacted (I) site and exposed in microcosms with increased Zn, Mn or Fe content, and to stream water from site R or I. Fungal biomass was higher in microcosms with leaves colonized at I and water from R. Fungal sporulation was higher in microcosms with leaves and water from R. Concentrations of 4.9, 9.6 and 5 ppm of Zn, Mn and Fe decrease fungal sporulation. The number of fungal species (spore counts and DGGE fingerprints) was lower in leaves colonized at site I. Cluster analyses of DGGE showed that Fe was the metal that most altered the structure of fungal community. Our results suggest that metal pollution affect leaf-associated Fungi depending on metal identity and concentration, and effects appear to be less pronounced in metal-adapted communities. (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
-
effects of zn fe and mn on leaf litter breakdown by Aquatic Fungi a microcosm study
International Review of Hydrobiology, 2010Co-Authors: Adriana O Medeiros, Sofia Alexandra Ferreira Duarte, Claudia Pascoal, Fernanda Cassio, Manuel A S GracaAbstract:This project was funded by the European Union, through the Contract EVK1-CT-2001-00088 (Project RivFunction) and by the Portuguese Foundation for Science and Technology FCT (POCTI/BSE/34024/00). ADRIANA MEDEIROS received a grant from CAPES (2006 Processo n degrees 2696/05-3) and SOFIA DUARTE received a grant from FCT (SFRH/BD/13482/2003). We thank ELSA RODRIGUES and ARANCHA MARCOTEGUI for field and laboratorial assistance and JOAO PRATAS for quantification of heavy metals.
Manuel A S Graca - One of the best experts on this subject based on the ideXlab platform.
-
is diversity a buffer against environmental temperature fluctuations a decomposition experiment with Aquatic Fungi
Fungal Ecology, 2015Co-Authors: Ana Lucia Goncalves, Manuel A S Graca, Cristina CanhotoAbstract:Abstract We tested if species-rich fungal assemblages are functionally more efficient in leaf decomposition under environmental fluctuations than species-poor assemblages. We manipulated temperature fluctuations in laboratory microcosms in which oak leaf discs were inoculated with monocultures of Aquatic hyphomycetes or random mixtures of three or eight species and subjected to different temperature regimes, including three constant temperatures and temperature fluctuation regimes. Temperature regime and identity of fungal species inoculated in monoculture microcosms significantly affected decomposition rates: these increased with temperature, but across all temperature regimes species diversity promoted higher decomposition rate, although functional saturation seemed to occur above three species. In assemblages with at least eight species, litter decomposition was not inhibited by temperature fluctuating regime when compared with constant temperature conditions. Ecosystem function under environmental changes seems to benefit from the presence of multiple species.
-
effects of zn fe and mn on leaf litter breakdown by Aquatic Fungi a microcosm study
International Review of Hydrobiology, 2010Co-Authors: Adriana O Medeiros, Sofia Alexandra Ferreira Duarte, Claudia Pascoal, Fernanda Cassio, Manuel A S GracaAbstract:We investigated the effects of heavy metals on leaf litter decomposition in streams. Leaves were immersed (10 days) at a reference (R) and a metal-impacted (I) site and exposed in microcosms with increased Zn, Mn or Fe content, and to stream water from site R or I. Fungal biomass was higher in microcosms with leaves colonized at I and water from R. Fungal sporulation was higher in microcosms with leaves and water from R. Concentrations of 4.9, 9.6 and 5 ppm of Zn, Mn and Fe decrease fungal sporulation. The number of fungal species (spore counts and DGGE fingerprints) was lower in leaves colonized at site I. Cluster analyses of DGGE showed that Fe was the metal that most altered the structure of fungal community. Our results suggest that metal pollution affect leaf-associated Fungi depending on metal identity and concentration, and effects appear to be less pronounced in metal-adapted communities. (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
-
effects of zn fe and mn on leaf litter breakdown by Aquatic Fungi a microcosm study
International Review of Hydrobiology, 2010Co-Authors: Adriana O Medeiros, Sofia Alexandra Ferreira Duarte, Claudia Pascoal, Fernanda Cassio, Manuel A S GracaAbstract:This project was funded by the European Union, through the Contract EVK1-CT-2001-00088 (Project RivFunction) and by the Portuguese Foundation for Science and Technology FCT (POCTI/BSE/34024/00). ADRIANA MEDEIROS received a grant from CAPES (2006 Processo n degrees 2696/05-3) and SOFIA DUARTE received a grant from FCT (SFRH/BD/13482/2003). We thank ELSA RODRIGUES and ARANCHA MARCOTEGUI for field and laboratorial assistance and JOAO PRATAS for quantification of heavy metals.
-
diversity and activity of Aquatic Fungi under low oxygen conditions
Freshwater Biology, 2009Co-Authors: Adriana O Medeiros, Claudia Pascoal, Manuel A S GracaAbstract:Summary 1. The objective was to test whether a decrease in oxygen concentration in streams affects the diversity and activity of Aquatic hyphomycetes and consequently leaf litter decomposition. 2. Senescent leaves of Alnus glutinosa were immersed for 7 days in a reference stream, for fungal colonization, and then incubated for 18 days in microcosms at five oxygen concentrations (4%, 26%, 54%, 76% and 94% saturation). Leaf decomposition (as loss of leaf toughness), fungal diversity, reproduction (as spore production) and biomass (ergosterol content) were determined. 3. Leaf toughness decreased by 70% in leaves exposed to the highest O2 concentration, whereas the decrease was substantially less (from 25% to 45%) in treatments with lower O2. Fungal biomass decreased from 99 to 12 mg Fungi g−1 ash-free dry mass on exposure to 94% and 4% O2 respectively. Sporulation was strongly inhibited by reduction of dissolved O2 in water (3.1 × 104 versus 1.3 × 103 spores per microcosms) for 94% and 4% saturation respectively. 4. A total of 20 species of Aquatic hyphomycetes were identified on leaves exposed to 94% O2, whereas only 12 species were found in the treatment with 4% O2 saturation. Multidimensional scaling revealed that fungal assemblages exposed to 4% O2 were separated from all the others. Articulospora tetracladia, Cylindrocarpon sp. and Flagellospora curta were the dominant species in microcosms with 4% O2, while Flagellospora curvula and Anguillospora filiformis were dominant at higher O2 concentrations. 5. Overall results suggest that the functional role of Aquatic hyphomycetes as decomposers of leaf litter is limited when the concentration of dissolved oxygen in streams is low.