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1.
Environ Toxicol Chem ; 41(4): 888-895, 2022 04.
Artigo em Inglês | MEDLINE | ID: mdl-34003520

RESUMO

Benthic communities contain some of the most threatened organisms in aquatic habitats due to different anthropogenic pressures. The high abundance of microplastics in sediments will continue to increase in the future, further increasing the probability of interactions between macroinvertebrates and microplastics. In the present study, a benthic community in a relatively pristine shallow pond was exposed either to an environmentally relevant high concentration of a microplastic mixture of 80 g m-2 in the sediment, or a control sediment, without the addition of microplastics. The mixture of microplastics contained irregularly shaped polyethylene, polyvinyl chloride, and polyamide in a ratio of 50:25:25%, respectively. The in situ experiment lasted for 100 d. The total number of taxa that colonized the microcosms was 22 (17 in the control and 18 in the microplastic treatment), and the colonization was not affected by the treatment. The most dominant group within the macroinvertebrate community was the dipteran family Chironomidae, in both the control and the microplastic treatment. No significant differences in the abundance and biomass at a community level were recorded between the groups by permutational multivariate analysis of variance (F = 0.993, p = 0.456 and F = 0.344, p = 0.797, respectively). The mixture of microplastics did not influence the abundance or biomass of the functional feeding groups (F = 1.810, p = 0.137 and F = 0.377, p = 0.736, respectively). The species richness, species abundance, species biomass, Shannon's diversity index, and Simpson's index of diversity showed no statistically significant differences between the control and treatment groups. Czekanowski's quantitative similarity index indicated that 84% of the community remained unaffected after microplastic exposure. Environ Toxicol Chem 2022;41:888-895. © 2021 SETAC.


Assuntos
Microplásticos , Poluentes Químicos da Água , Monitoramento Ambiental , Água Doce , Sedimentos Geológicos , Plásticos/análise , Plásticos/toxicidade , Lagoas , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/toxicidade
2.
J Med Entomol ; 56(4): 967-978, 2019 06 27.
Artigo em Inglês | MEDLINE | ID: mdl-31220292

RESUMO

Many morphologically similar species of the simuliid (Diptera: Simuliidae) subgenus Wilhelmia, Enderlein are difficult to distinguish. Thus, the revision of the subgenus using various morphological, cytogenetic, and genetic analyses has been attempted. Neglected until now, the Balkan Peninsula, a crossroad between Europe and Anatolia, provides insight which could resolve problematic interrelationships of the taxa within this subgenus. To uncover the status and relations within the subgenus Wilhelmia, mtDNA was extracted from 47 individuals of six morphospecies: Simulium balcanicum (Enderlein, 1924), Simulium turgaicum Rubtsov, 1940, Simulium lineatum (Meigen, 1804), Simulium pseudequinum Séguy, 1921, Simulium equinum (Linnaeus, 1758), and Simulium paraequinum Puri, 1933 from 21 sites throughout the Balkan Peninsula. Phylogenetic analysis of the Wilhelmia species using mitochondrial DNA barcoding (COI) gene showed two major branches, the lineatum branch, which includes the lineages sergenti, paraequinum, and lineatum, and the equinum branch. In the equinum branch, the mtDNA sequences formed six clades, with high genetic distances, suggesting the existence of different species. Historically, the clades of the equinum branch appeared at numerous islands, perhaps as a result of allopatric speciation. The paraequinum lineage (lineatum branch) is composed of two species. However, six clades of the lineatum lineage overlapped with intra- and interspecific genetic distances. Our results revealed that the species S. balcanicum, S. pseudequinum B, and S. equinum were omnipresent in the Balkans. The results point to not only the fair diversity of Wilhelmia species in the Balkans, but also indicate that most Wilhelmia species live in sympatry.


Assuntos
Simuliidae/genética , Animais , Península Balcânica , Filogeografia
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