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A. Economou-amilli - One of the best experts on this subject based on the ideXlab platform.
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Epiphytic patterns of macroalgal assemblages on Cystoseira species (Fucales, Phaeophyta) in the east coast of Attica (Aegean Sea, Greece)
Hydrobiologia, 1999Co-Authors: M. R. Belegratis, I. Bitis, A. Economou-amilliAbstract:Epiphytic macroalgal assemblages growing on Cystoseira species were examined at typical oligotrophic and Eutrophic sites of the east coast of Attica (Aegean Sea, Greece) from November 1995 to September 1996. The epiphytic patterns of C. spinosa Sauvageau thriving in the oligotrophic area of Dikastika and of C. compressa (Esper) Gerloff & Nizzamudin growing in the Eutrophic Environment of Avlida, were compared through a cross-transplantation experiment. Seasonality effects on epiphytic assemblages were observed. The species composition was exclusive for each locality, reflecting differences in the trophic status of the two sites. No specific pattern of epiphytes' distribution was found on the hosts. The prolific epiphytic growth in the oligotrophic site resulted in a reduction of the photosynthetic tissue of both hosts ( C. spinosa and the transplanted C. compressa ) and the survivorship of host plants was not negatively affected by the physical drag caused by the high epiphyte densities. Cystoseira spinosa survived in oligotrophic conditions despite its heavy epiphytic load. C. compressa was also able to cope with the adverse epiphytic influence in the Eutrophic conditions of Avlida; although being perennial, it sheds parts of its stipe and branches before the resting period and sprouts prior to other algae at the beginning of spring.
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Epiphytic patterns of macroalgal assemblages on Cystoseira species (Fucales, Phaeophyta) in the east coast of Attica (Aegean Sea, Greece)
Hydrobiologia, 1999Co-Authors: M. R. Belegratis, I. Bitis, A. Economou-amilli, Jörg A. OttAbstract:Epiphytic macroalgal assemblages growing on Cystoseira species were examined at typical oligotrophic and Eutrophic sites of the east coast of Attica (Aegean Sea, Greece) from November 1995 to September 1996. The epiphytic patterns of C. spinosa Sauvageau thriving in the oligotrophic area of Dikastika and of C. compressa (Esper) Gerloff & Nizzamudin growing in the Eutrophic Environment of Avlida, were compared through a cross-transplantation experiment. Seasonality effects on epiphytic assemblages were observed. The species composition was exclusive for each locality, reflecting differences in the trophic status of the two sites. No specific pattern of epiphytes' distribution was found on the hosts. The prolific epiphytic growth in the oligotrophic site resulted in a reduction of the photosynthetic tissue of both hosts (C. spinosa and the transplanted C. compressa) and the survivorship of host plants was not negatively affected by the physical drag caused by the high epiphyte densities. Cystoseira spinosa survived in oligotrophic conditions despite its heavy epiphytic load. C. compressa was also able to cope with the adverse epiphytic influence in the Eutrophic conditions of Avlida; although being perennial, it sheds parts of its stipe and branches before the resting period and sprouts prior to other algae at the beginning of spring.
M. R. Belegratis - One of the best experts on this subject based on the ideXlab platform.
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Epiphytic patterns of macroalgal assemblages on Cystoseira species (Fucales, Phaeophyta) in the east coast of Attica (Aegean Sea, Greece)
Hydrobiologia, 1999Co-Authors: M. R. Belegratis, I. Bitis, A. Economou-amilliAbstract:Epiphytic macroalgal assemblages growing on Cystoseira species were examined at typical oligotrophic and Eutrophic sites of the east coast of Attica (Aegean Sea, Greece) from November 1995 to September 1996. The epiphytic patterns of C. spinosa Sauvageau thriving in the oligotrophic area of Dikastika and of C. compressa (Esper) Gerloff & Nizzamudin growing in the Eutrophic Environment of Avlida, were compared through a cross-transplantation experiment. Seasonality effects on epiphytic assemblages were observed. The species composition was exclusive for each locality, reflecting differences in the trophic status of the two sites. No specific pattern of epiphytes' distribution was found on the hosts. The prolific epiphytic growth in the oligotrophic site resulted in a reduction of the photosynthetic tissue of both hosts ( C. spinosa and the transplanted C. compressa ) and the survivorship of host plants was not negatively affected by the physical drag caused by the high epiphyte densities. Cystoseira spinosa survived in oligotrophic conditions despite its heavy epiphytic load. C. compressa was also able to cope with the adverse epiphytic influence in the Eutrophic conditions of Avlida; although being perennial, it sheds parts of its stipe and branches before the resting period and sprouts prior to other algae at the beginning of spring.
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Epiphytic patterns of macroalgal assemblages on Cystoseira species (Fucales, Phaeophyta) in the east coast of Attica (Aegean Sea, Greece)
Hydrobiologia, 1999Co-Authors: M. R. Belegratis, I. Bitis, A. Economou-amilli, Jörg A. OttAbstract:Epiphytic macroalgal assemblages growing on Cystoseira species were examined at typical oligotrophic and Eutrophic sites of the east coast of Attica (Aegean Sea, Greece) from November 1995 to September 1996. The epiphytic patterns of C. spinosa Sauvageau thriving in the oligotrophic area of Dikastika and of C. compressa (Esper) Gerloff & Nizzamudin growing in the Eutrophic Environment of Avlida, were compared through a cross-transplantation experiment. Seasonality effects on epiphytic assemblages were observed. The species composition was exclusive for each locality, reflecting differences in the trophic status of the two sites. No specific pattern of epiphytes' distribution was found on the hosts. The prolific epiphytic growth in the oligotrophic site resulted in a reduction of the photosynthetic tissue of both hosts (C. spinosa and the transplanted C. compressa) and the survivorship of host plants was not negatively affected by the physical drag caused by the high epiphyte densities. Cystoseira spinosa survived in oligotrophic conditions despite its heavy epiphytic load. C. compressa was also able to cope with the adverse epiphytic influence in the Eutrophic conditions of Avlida; although being perennial, it sheds parts of its stipe and branches before the resting period and sprouts prior to other algae at the beginning of spring.
Graciela S. Diniz - One of the best experts on this subject based on the ideXlab platform.
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Tissue Nitrogen and Phosphorus in Seaweeds in a Tropical Eutrophic Environment: What a Long-Term Study Tells Us
Journal of Applied Phycology, 2006Co-Authors: Sergio O. Lourenço, Elisabete Barbarino, Andyara Nascimento, Joana N. P. Freitas, Graciela S. DinizAbstract:Percentages of nitrogen and phosphorus in 10 species of seaweeds (6 green and 4 red algae) were monitored from 1997 to 2004 by seasonal sampling in Guanabara Bay, South-eastern Brazil. The species did not show consistent variations in tissue N , P and N : P that related to annual cycles. Throughout this study, higher percentages of tissue N and P were found in Bostrychia radicans and Grateloupia doryphora (red algae) and lower in Cladophora rupestris and Codium decorticatum (green algae). In November 1999, the Icaraí Submarine Sewage Outfall became operational, resulting in a reduction of visual pollution in the area and an improvement in the local quality of seawater for recreational use. Measurements of dissolved nutrients at the sampling site did not indicate significant changes in concentrations after the commissioning of the submarine sewage outfall; however, tissue P and N : P ratio of most of species were significantly lower than in the first two years of this survey. Variations in tissue nitrogen throughout this study were not significant, except for G. doryphora in some comparisons. Results show that seaweeds function very well as monitors of Environmental changes in Guanabara Bay. Experimental data are needed to identify possible Environmental processes which are promoting changes in chemical composition of the local seaweed populations.
Odete Rocha - One of the best experts on this subject based on the ideXlab platform.
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Evaluation of cyanobacteria toxicity in tropical reservoirs using crude extracts bioassay with cladocerans
Ecotoxicology, 2007Co-Authors: Denise Tieme Okumura, Rosana Barbosa Sotero-santos, Renata Akemi Takenaka, Odete RochaAbstract:During a cyanobacterial bloom in a Eutrophic Environment, particularly at the end when decomposition occurs, toxic compounds such as the cyanotoxins and the lipopolysaccharides can be released in high concentrations into the water column damaging aquatic organisms. In this work, the effects of this release of toxic compounds during a cyanobacterial bloom were investigated. The acute and chronic toxicity of cyanobacterial crude extracts from two natural blooms in the Barra Bonita and Ibitinga reservoirs (Middle Tietê River, São Paulo State, Brazil) and of a toxic strain cultured in the laboratory were tested. The cladocerans Daphnia similis , Ceriodaphnia dubia and Ceriodaphnia silvestrii were used as test organisms. In the chronic toxicity tests, only a native cladoceran found in Brazilian freshwaters, Ceriodaphnia silvestrii , was used. Microcystins were detected in all cyanobacterial samples. The acute toxicity tests showed that the crude bloom material extract from the Ibitinga Reservoir (48-h EC_50 values between 32.6 and 35.8 μg microcystin g^−1 of freeze-dried material) exhibited higher toxicity to cladoceran than did the crude bloom material extract from Barra Bonita Reservoir (48-h EC_50 values between 46.0 and 80.2 μg microcystin g^−1 of freeze-dried material). The chronic toxicity test data showed that the three extracts reduced the fecundity of C. silvestrii , and the crude extract of Barra Bonita Reservoir bloom material also affected the survival of this cladoceran. Both acute and chronic tests effectively prognosticated possible changes in the cladoceran population, and probably other components of the biota due to cyanobacterial blooms in natural aquatic ecosystems.
Jörg A. Ott - One of the best experts on this subject based on the ideXlab platform.
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Epiphytic patterns of macroalgal assemblages on Cystoseira species (Fucales, Phaeophyta) in the east coast of Attica (Aegean Sea, Greece)
Hydrobiologia, 1999Co-Authors: M. R. Belegratis, I. Bitis, A. Economou-amilli, Jörg A. OttAbstract:Epiphytic macroalgal assemblages growing on Cystoseira species were examined at typical oligotrophic and Eutrophic sites of the east coast of Attica (Aegean Sea, Greece) from November 1995 to September 1996. The epiphytic patterns of C. spinosa Sauvageau thriving in the oligotrophic area of Dikastika and of C. compressa (Esper) Gerloff & Nizzamudin growing in the Eutrophic Environment of Avlida, were compared through a cross-transplantation experiment. Seasonality effects on epiphytic assemblages were observed. The species composition was exclusive for each locality, reflecting differences in the trophic status of the two sites. No specific pattern of epiphytes' distribution was found on the hosts. The prolific epiphytic growth in the oligotrophic site resulted in a reduction of the photosynthetic tissue of both hosts (C. spinosa and the transplanted C. compressa) and the survivorship of host plants was not negatively affected by the physical drag caused by the high epiphyte densities. Cystoseira spinosa survived in oligotrophic conditions despite its heavy epiphytic load. C. compressa was also able to cope with the adverse epiphytic influence in the Eutrophic conditions of Avlida; although being perennial, it sheds parts of its stipe and branches before the resting period and sprouts prior to other algae at the beginning of spring.
