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Resultados 1321-1330 de 4,308
Chemoreception drives plastic consumption in a hard coral Texto completo
2017
Allen, Austin S. | Seymour, Alexander C. | Rittschof, Daniel
The drivers behind microplastic (up to 5mm in diameter) consumption by animals are uncertain and impacts on foundational species are poorly understood. We investigated consumption of weathered, unfouled, biofouled, pre-production and microbe-free National Institute of Standards plastic by a scleractinian coral that relies on chemosensory cues for feeding. Experiment one found that corals ingested many plastic types while mostly ignoring organic-free sand, suggesting that plastic contains phagostimulents. Experiment two found that corals ingested more plastic that wasn't covered in a microbial biofilm than plastics that were biofilmed. Additionally, corals retained ~8% of ingested plastic for 24h or more and retained particles appeared stuck in corals, with consequences for energetics, pollutant toxicity and trophic transfer. The potential for chemoreception to drive plastic consumption in marine taxa has implications for conservation.
Mostrar más [+] Menos [-]Detecting long-term temporal trends in sediment-bound metals in the western Adriatic (Mediterranean Sea) Texto completo
2017
Lopes-Rocha, Marilia | Langone, Leonardo | Miserocchi, Stefano | Giordano, Patrizia | Guerra, Roberta
Major and trace metal concentrations were determined in western Adriatic sediment cores. Based on sediment chronology, the earliest anthropogenic influence appeared as a Zn and Pb increase in the Po River prodelta starting from ~1914. The increasing contamination signal of these trace metals propagated southward as far as 450km with a growing delay, taking ~10years to reach the south Adriatic Sea. Although greater inventories of excess trace metals in the northern sector pointed to the influence of the intense human activities in the Po River drainage basin and Venice lagoon system, we observed a reduction of excess trace metals from mid-1980s, related to the implementation of stricter environmental regulations on chemical wastewaters. In contrast, an increase in trace metal accumulation in surficial sediment from the 2000s in front of the cities of Ancona and Bari suggested a recent local input of trace metals, probably due to harbor activities.
Mostrar más [+] Menos [-]Pollutants and biomarker responses in two reef fish species (Haemulon aurolineatum and Ocyurus chrysurus) in the Southern Gulf of Mexico Texto completo
2017
Gold-Bouchot, Gerardo | Rubio-Piña, J. | Montero-Muñoz, J. | Ramirez-Miss, N. | Echeverría-García, A. | Patiño-Suarez, V. | Puch-Hau, C.A. | Zapata-Pérez, O.
The environmental quality differences between two groups of reefs in the Veracruz Reef System were evaluated. The North group of reefs is very close to Veracruz, an urban and port zone, whereas the South group is more isolated, with minor anthropogenic disturbances. To prove the hypothesis that the North group is more affected by anthropogenic activities, the concentrations of hydrocarbons in liver, metals and metalloids such as Se, As, Ba, Cd, Hg and V in muscle, and PAH metabolites in bile were evaluated, and related to biomarkers (transcript abundance of cytochrome P4501A, Vitellogenin, and Glutathione-S-transferase) in two species of fish: Haemulon aurolineatum and Ocyurus chysurus. H. aurolineatum presents the highest concentrations for many pollutants, but O. chysurus shows the most significant differences in pollutant concentrations and biomarkers between the two reef groups, suggesting that this species could be used as a sentinel in future studies in the Gulf of Mexico.
Mostrar más [+] Menos [-]Bacterial interactions and implications for oil biodegradation process in mangrove sediments Texto completo
2017
Grativol, Adriana Daudt | Marchetti, Albany A | Wetler-Tonini, Rita M | Venancio, Thiago M | Gatts, Carlos EN | Thompson, Fabiano L | Rezende, Carlos E
Mangrove sediment harbors a unique microbiome and is a hospitable environment for a diverse group of bacteria capable of oil biodegradation. Our goal was to understand bacterial community dynamics from mangrove sediments contaminated with heavy-oil and to evaluate patterns potentially associated with oil biodegradation is such environments. We tested the previously proposed hypothesis of a two-phase pattern of petroleum biodegradation, under which key events in the degradation process take place in the first three weeks after contamination. Two sample sites with different oil pollution histories were compared through T-RFLP analyses and using a pragmatic approach based on the Microbial Resource Management Framework. Our data corroborated the already reported two-phase pattern of oil biodegradation, although the original proposed explanation related to the biophysical properties of the soil is questioned, opening the possibility to consider other plausible hypotheses of microbial interactions as the main drivers of this pattern.
Mostrar más [+] Menos [-]Lost in the North: The first record of Diretmichthys parini (Post and Quéro, 1981) in the northern North Sea Texto completo
2017
Cresson, Pierre | Rouquette, Manuel | Marco-miralles, Francoise | Dufour, Jean-louis | Causse, Romain | Bouchoucha, Marc | Mahe, Kelig
In June 2015, an individual of Diretmichthys parini (Post and Quero, 1981) was trawled at 530 m depth, in the North Sea off Norway and donated to research. This capture, the first for this species in the North Sea was the northernmost recorded so far, and provided an opportunity to document some aspects of the biology and ecology of this data-poor species. This individual was a female, 331 mm total length of 33 years old, with low mercury content in muscle and liver (~ 0.2 μg g− 1 wet mass). Stable isotope ratios (C and N) in muscle and liver were consistent with the planktonic diet expected for this species. The capture of this fish at the northern latitude known so far would be consistent with the extension of the home range and the latitudinal shift hypothesized for this species in the 1990′s.
Mostrar más [+] Menos [-]Underestimation of chemical contamination in marine fish muscle tissue can be reduced by considering variable wet:dry weight ratios Texto completo
2017
Cresson, Pierre | Travers-trolet, Morgane | Rouquette, Manuel | Timmerman, Charles-andre | Giraldo, Carolina | Lefebvre, Sebastien | Ernande, Bruno
Whether considered as a risk for human health or as ecological tracers, contaminants' concentrations measured in fish muscles are commonly expressed relative to wet or dry mass. Comparison of results required conversion factors (CF) but accurate values are scarce and case-specific. The present paper is aimed at investigating errors linked with the use of the theoretical value. Muscles dry and wet masses were measured in 15 fish species to determine the actual CF. Most CF were lower than the theoretical wet:dry ratio of 5 classically used, with variations at individual and species level. Muscle lipid content (inferred by C/N ratios) was a crucial factor explaining discrepancies, claiming for caution when working with lipid-rich species. The observed variability demonstrated that using the theoretical CF may be inaccurate, when actual CF largely differs from the theoretical value. Dedicated measurement is the better approach when accuracy is required.
Mostrar más [+] Menos [-]Degradation of N-Nitrosodimethylamine by UV-Based Advanced Oxidation Processes for Potable Reuse: a Short Review Texto completo
2017
Fujioka, Takahiro | Masaki, Shunya | Kodamatani, Hitoshi | Ikehata, Keisuke
The ultraviolet (UV)-based advanced oxidation process (AOP) is a powerful technology commonly utilised in recent potable water reuse (PR) schemes. The AOP involves the generation of highly reactive free radicals (e.g. hydroxyl, HO•) and is primarily applied for the removal of two target trace organic chemicals—N-nitrosodimethylamine (NDMA) and 1,4-dioxane — in the PR schemes. Both of these organics are not well removed by the reverse osmosis (RO) process. NDMA is a probable carcinogen and is often present in reclaimed water at concentrations higher than the guidelines established for PR. This review aimed to provide an understanding of the current UV-based advanced oxidation technologies for NDMA removal in PR, their limitations and the future of advanced technologies for their removal. NDMA is readily photolysed by direct UV irradiation, while an AOP such as UV/H₂O₂ process is necessary for the destruction of 1,4-dioxane. Unfortunately, the generation of hydroxyl radicals through UV photolysis of H₂O₂ is largely inefficient with conversion on the order of 20% under normal plant operations and the addition of H₂O₂ (e.g. 3 mg/L) provides only a negligible improvement in NDMA destruction. However, AOP can also be achieved without continuous chemical addition through the application of UV irradiation to heterogeneous photocatalysts (e.g. TiO₂). The UV/TiO₂ process generates hydroxyl radicals and singlet oxygen molecules, both of which degrade NDMA into by-products (e.g. methylamine or dimethylamine). Recent studies revealed that modification of the surface morphology of TiO₂ can not only enhance NDMA destruction but also alter the composition of the degradation by-products.
Mostrar más [+] Menos [-]Optimization of a cloud point extraction procedure with response surface methodology for the quantification of dissolved iron in produced water from the petroleum industry using FAAS Texto completo
2017
Gondim, Tamyris A. | Guedes, Jhonyson A.C. | Ribeiro, Livia P.D. | Lopes, Gisele S. | Matos, Wladiana O.
The characterization of inorganic elements in the produced water (PW) samples is a difficult task because of the complexity of the matrix. This work deals with a study of a methodology for dissolved Fe quantification in PW from oil industry by flame atomic absorption spectrometry (FAAS) after cloud point extraction (CPE). The procedure is based on the CPE using PAN as complexing agent and Triton X-114 as surfactant. The best conditions for Fe extraction parameters were studied using a Box-Behnken design. The proposed method presented a LOQ of 0.010μgmL−1 and LOD of 0.003μgmL−1. The precision of the method was evaluated in terms of repeatability, obtaining a coefficient of variation of 2.54%. The accuracy of the method was assessed by recovery experiments of Fe spiked that presented recovery of 103.28%. The method was applied with satisfactory performance to determine Fe by FAAS in PW samples.
Mostrar más [+] Menos [-]Tributyltin exposure increases mortality of nodavirus infected Japanese medaka Oryzias latipes larvae Texto completo
2017
Kitamura, Shin-Ichi | Akizuki, Masaki | Song, Jun-Young | Nakayama, Kei
We investigated the effect of combined exposure to nodavirus infection and TBT on medaka (Oryzias latipes). Medaka larvae were infected by immersion in medium containing nodavirus at titers of 102.5, 103.5, or 104.5 TCID50/mL. Infected fish then were exposed to TBT at 0, 0.17, 0.52, 1.6, or 4.7μg/L. Of the 12 groups exposed to both stressors, the mortalities of 6 (102.5 TCID50/mL+0.52, 1.6, or 4.7μg/L, 103.5 TCID50/mL+4.7μg/L and 104.5 TCID50/mL+1.6 or 4.7μg/L) were significantly higher than that of each TBT control. Specifically, mortality was 46±5.5% in the group exposed to both 102.5 TCID50/mL virus and 0.52μg/L TBT, which represent the lowest observed effective dose and concentration, respectively, among the 6 groups with increased mortalities. Our results suggest that combined exposure to both stressors suppresses antiviral mechanisms in the fish, thus increasing mortality.
Mostrar más [+] Menos [-]Preventable fine sediment export from the Burdekin River catchment reduces coastal seagrass abundance and increases dugong mortality within the Townsville region of the Great Barrier Reef, Australia Texto completo
2017
Wooldridge, Scott A
The coastal seagrass meadows in the Townsville region of the Great Barrier Reef are crucial seagrass foraging habitat for endangered dugong populations. Deteriorating coastal water quality and in situ light levels reduce the extent of these meadows, particularly in years with significant terrestrial runoff from the nearby Burdekin River catchment. However, uncertainty surrounds the impact of variable seagrass abundance on dugong carrying capacity. Here, I demonstrate that a power-law relationship with exponent value of −1 (R2~0.87) links mortality data with predicted changes in annual above ground seagrass biomass. This relationship indicates that the dugong carrying capacity of the region is tightly coupled to the biomass of seagrass available for metabolism. Thus, mortality rates increase precipitously following large flood events with a response lag of <12-months. The management implications of this result are discussed in terms of climate scenarios that indicate an increased future likelihood of extreme flood events.
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