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| ENRICH-PRAST,A.; ESTEVES,F. A.; BIESBOER,D. D.. |
| Estimates of the rates of heterotrophic nitrogen fixation (HNF) and denitrification by acetylene reduction and acetylene inhibition, respectively, were determined for the roots and culms of wild rice, Oryza glumaepatula, in Lake Batata, a lake severely impacted by the dumping of bauxite tailings into the lake basin. Two stations were established in different parts of the lake: one in a natural area and other in an impacted area of the lake. Plant assays were performed during the principle hydroperiods of dry (December) and flood (July) to determine both: a) Actual rates of HNF and denitrification, and b) potential rates of HNF after amending with glucose potential rates of denitrification after amending with glucose, glucose + nitrate, or nitrate alone.... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Biological nitrogen fixation; Amazonian lake; Aquatic macrophyte. |
| Ano: 1999 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0034-71081999000300013 |
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| PETRUCIO,M. M.; ESTEVES,F. A.. |
| The main goal of this research was to quantify the concentrations of total and ammonium N, nitrate, total and soluble P in the water in the presence of Eichhornia crassipes and Salvinia auriculata, which were submitted to two different photoperiods in a 24 hours incubation period in the laboratory. The macrophytes were incubated in plastic vials of approximately 1.5 litters, with a previously prepared solution with NH4NO3, NH4Cl, and KH2PO4. Eichhornia crassipes showed the highest average rate of reduction of all the nutrients analysed in relation to Salvinia auriculata. The largest photoperiod reflected in a higher average rate of reduction of nutrients, in both plants. Therefore, we may expect that in some periods of the year (e.g. summer), the aquatic... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Eichhornia crassipes; Aquatic macrophytes; Nitrogen; Phosphorus; Salvinia auriculata. |
| Ano: 2000 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0034-71082000000300002 |
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| ALBERTONI,E. F.; PALMA-SILVA,C.; ESTEVES,F. A.. |
| The northern part of the state of Rio de Janeiro shelters many coastal lagoons, located, mostly, in the "restinga" strip that stretches from the municipality of Macaé to the municipality of Quissamã. During 1995 and 1996 samplings were made aiming to verify the diversity and density of Natantia larvae in the Imboassica, Cabiúnas and Comprida lagoons. The monthly samples were taken with a 500 µ net, in horizontal drags from a boat. In Comprida lagoon no larvae of any family of these crustaceans were found. In Cabiúnas lagoon, the autumn was the season of the year with greatest relative abundance, the larvae belonging to only one genus: Macrobrachium. In Imboassica Lagoon samples were taken in two situations related to the variation of the water level and... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Coastal lagoons; Larvae; Penaeidae; Palaemonidae; Crustacea; Distribution. |
| Ano: 1999 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0034-71081999000100014 |
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