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Accumulation of nylon microplastics and polybrominated diphenyl ethers and effects on gut microbial community of Chironomus sancticaroli
Microplastics (MP) are emerging contaminants with the capacity to bind and transport hydrophobic organic compounds of environmental concern, such as polybrominated diphenyl ethers (PBDEs). The aim of this study was to investigate the ingestion of nylon (polyamide) MP alone and when associated with PBDEs and their effects on Chironomus sancticaroli larvae survival and microbiome structure. Survival, PBDE uptake and microbial community composition were measured in fourth instar larvae exposed for 96 h to BDEs- 47, 99, 100 and 153 in the presence and absence of 1% w/w MP in sediment. Microbiome community structures were determined through high throughput sequencing of 16S small subunit ribosomal RNA gene (16S rRNA). Initial experiments showed that larvae ingested MP faster at 0.5% w/w MP, while depuration was more efficient at 1% w/w MP, although retention of MP was seen even after 168 h depuration. No mortality was observed as a result of PBDEs and MP exposure. MP had a negative effect on PBDE concentration within larvae (η2 = 0.94) and a negative effect on sediment concentrations (η2 = 0.48). In all samples, microbial communities were dominated by Alphaproteobacteria, Betaproteobacteria, Actinobacteria and Gammaproteobacteria. Bacterial alpha diversity was not significantly affected by PBDEs or MP exposure. However, the abundance of discrete bacterial taxa was more sensitive to MP (X2 = 45.81, p = 0.02), and PBDE exposure. Our results highlight that C. sancticaroli showed no acute response to MPs and PBDEs, but that MPs influenced bacterial microbiome structure even after only short-term acute exposure
Extração de nutrientes pela parte aérea de carqueja sob a influência de fontes e doses de nitrogênio Nutrient extraction for shoots of carqueja under fonts and levels of nitrogen
O objetivo deste trabalho foi determinar a influência das fontes e doses de nitrogênio no teor e na extração de nutrientes na parte aérea de carqueja seis meses após o plantio, assim como sua relação com o rendimento de matéria seca e óleo essencial. O experimento foi conduzido na Estação Experimental de Canguiri (UFPR), com delineamento em blocos ao acaso, com sete tratamentos e quatro repetições em parcelas de 2m². Os tratamentos foram 4, 8 e 16g de nitrogênio (N) por planta, na forma de uréia; as mesmas quantidades de N na forma de esterco ovino; e o controle, sem aplicação de N. As adubações realizaram-se em duas aplicações com intervalo de dois meses. Não foram verificadas diferenças estatisticamente significativas entre tratamentos para o teor e a extração de nutrientes nestas condições de fertilidade do solo, o que também foi observado para a produção de matéria seca e o teor de óleo essencial. A quantidade de nutrientes extraídos pela parte aérea apresenta a seqüência decrescente K > N > Ca > S > Mg > P para os macronutrientes e de Mn >Fe > B > Zn > Cu para os micronutrientes.<br>This research was aimed at determining the influence of nitrogen sources and levels on the amount and concentration of nutrients extracted from the shoots of carqueja six months after planted. The amount and concentration were correlated to the essential oil and dry matter production. The experiment was conducted at Experimental Station of Canguiri (UFPR), with experimental design in random blocks with seven treatments and four repetitions. The treatments consisted of 4, 8 and 16 grams of nitrogen (N) per plant of urea and manure sources, and a control without N application. The fertilization was done two times with an interval of two months. There was no statistical difference between content and extraction of nutrients for treatments for these soil fertility conditions. Similar results were observed for dry matter and essential oil production. The nutrient extraction for aerial parts presented the decreasing sequence K > N > Ca > S > Mg > P for macronutrients and Mn >Fe > B > Zn > Cu for micronutrients