排序方式： 共有35条查询结果，搜索用时 734 毫秒
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Isa D.L. Gomes Marco F.L. Lemos Amadeu M.V.M. Soares Carlos Barata Melissa Faria 《Marine pollution bulletin》2014
The ecological relevance of polychaetes coupled with their easy culture and maintenance in the laboratory, has led them to become increasingly used in marine ecotoxicological studies, raising the need to validate frequently applied monitoring tools at various biological levels. The present study was aimed to characterize the cholinesterases (ChE) activity in the polychaete Capitella teleta, using three substrates (acetylthiocholine iodide, propionylthiocholine iodide, and S-butyrylthiocholine iodide) and four known inhibitors (eserine hemisulfate, BW284c51, iso-OMPA and chlorpyrifos-oxon). Results showed that most of the measured cholinesterase activity was acetylcholinesterase (AChE). Inhibition of enzyme kinetic experiments denoted that sensitivity of C. teleta’s ChE to the organophosphorous metabolite chlorpyrifos-oxon (IC50 = 60.72 nM) was analogous to some fish species. This study highlights the relevance of ChE characterization before its use as a biomarker in ecotoxicology and biomonitoring studies. 相似文献
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In this research, the bioremediation of dispersed crude oil, based on the amount of nitrogen and phosphorus supplementation in the closed system, was optimized by the application of response surface methodology and central composite design. Correlation analysis of the mathematical‐regression model demonstrated that a quadratic polynomial model could be used to optimize the hydrocarbon bioremediation (R2 = 0.9256). Statistical significance was checked by analysis of variance and residual analysis. Natural attenuation was removed by 22.1% of crude oil in 28 days. The highest removal on un‐optimized condition of 68.1% were observed by using nitrogen of 20.00 mg/L and phosphorus of 2.00 mg/L in 28 days while optimization process exhibited a crude oil removal of 69.5% via nitrogen of 16.05 mg/L and phosphorus 1.34 mg/L in 27 days therefore optimization can improve biodegradation in shorter time with less nutrient consumption. 相似文献
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Ma Carmen Ávila-López J. Martín Hernández-Ayón Víctor F. Camacho-Ibar Armando Félix Bermúdez Adan Mejía-Trejo Isaí Pacheco-Ruiz Jose M. Sandoval-Gil 《Estuaries and Coasts》2017,40(3):792-806
The present study examines the temporal variability of air–water CO2 fluxes (FCO2) and seawater carbonate chemistry in a Baja California coastal lagoon during an exceptionally warm anomaly that was developed in Northeast Pacific coasts during 2014. This oceanographic condition led to a summer-like season (weak upwelling condition) during the study period, which reached a maximum surface temperature anomaly of 2 °C in September 2014. San Quintín Bay acts as a source of CO2 to the atmosphere in 2014 (3.3 ± 4.8 mmol C m?2 day?1) with the higher positive fluxes mainly observed in summer months (9.0 ± 5.3 mmol C m?2 day?1). Net ecosystem production (NEP) switched seasonally between net heterotrophy and net autotrophy during the study period, with an annual average of 2.2 ± 7.1 mmol C m?2 day?1, which indicates that San Quintín Bay was a net autotrophic system during the atypical warm oceanographic condition in 2014. This pattern of seasonal variations in the carbon balance at San Quintín Bay appears to be linked to the life cycle of benthic communities, which play an important role in the whole-ecosystem metabolism. Under the limited input from external sources coupled with an increase in seawater temperatures, the recycled benthic carbon and nutrient fluxes play a major role to sustain water-column processes within the bay. Since the upwelling condition may influence the magnitude of the air–water CO2 fluxes, our results clearly indicated that San Quintín Bay is a net source of carbon to the atmosphere regardless of the adjacent oceanic conditions. Our study sheds light on the carbon dynamics and its metabolic implications in a shallow coastal ecosystem under a regional warm anomaly and contributes potentially relevant information in view of the likely future scenario of global climate change. 相似文献
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Spatial distribution of heavy metals in surficial sediments from Guanabara Bay: Rio de Janeiro, Brazil 总被引：1，自引：0，他引：1
José Antônio Baptista Neto Franz Xaver Gingele Thomas Leipe Isa Brehme 《Environmental Geology》2006,49(7):1051-1063
Ninety-two surface sediment samples were collected in Guanabara Bay, one of the most prominent urban bays in SE Brazil, to
investigate the spatial distribution of anthropogenic pollutants. The concentrations of heavy metals, organic carbon and particle
size were examined in all samples. Large spatial variations of heavy metals and particle size were observed. The highest concentrations
of heavy metals were found in the muddy sediments from the north western region of the bay near the main outlets of the most
polluted rivers, municipal waste drainage systems and one of the major oil refineries. Another anomalous concentration of
metals was found adjacent to Rio de Janeiro Harbour. The heavy metal concentrations decrease to the northeast, due to intact
rivers and the mangrove systems in this area, and to the south where the sand fraction and open-marine processes dominate.
The geochemical normalization of metal data to Li or Al has also demonstrated that the anthropogenic input of heavy metals
have altered the natural sediment heavy metal distribution. 相似文献