خيارات البحث
النتائج 1851 - 1860 من 5,137
Use of a monoclonal antibody-based assay for the early detection of an invasive bivalve in plankton samples
2018
Montes, Agar | Lorenzo-Abalde, Silvia | González Fernández, África | Vázquez, Elsa | Olabarria, Celia
The invasive mussel Xenostrobus securis was recorded for the first time in the Galician Rias Baixas (NW Spain) in 2007, within an area characterized by intense commercial culture of Mytilus galloprovincialis. The main aims of this study were to evaluate whether an immunological assay can be used to detect larvae of this species in field samples of plankton and to determine whether the distribution of larvae matched that of adults. The ability of two monoclonal antibodies to recognize the bivalve was tested by immunofluorescence. Only the M22.8 antibody recognized X. securis larvae. The staining pattern distinguished X. securis from M. galloprovincialis larvae in both laboratory cultures and field samples of plankton. The distribution of larvae did not match that of adults. This tool may prove very useful for monitoring the presence of this invasive species in the plankton, allowing rapid and specific recognition.
اظهر المزيد [+] اقل [-]Differential impact of marine debris ingestion during ontogenetic dietary shift of green turtles in Uruguayan waters
2018
Vélez-Rubio, G.M. | Teryda, N. | Asaroff, P.E. | Estrades, A. | Rodriguez, D. | Tomas, J.
Anthropogenic debris ingestion has been reported for green turtles in all their life stages worldwide. The aim of the present study is to evaluate the marine debris ingestion by green turtles stranded in Uruguayan coast between 2005 and 2013. Debris items were categorized and quantified by frequency of occurrence, relative weight, volume and number of items. A total of 96 dead stranded turtles were analyzed and 70% presented debris in their guts. The majority of debris found were plastic, being hard plastics the most abundant in weight. We found no differences in debris ingestion in stranded turtles a long the Uruguayan coast. However we detected a negative correlation between the presence of debris and turtle's size. Smaller turtles are new recruits to neritic grounds indicating that the early juvenile stage of this species is the most vulnerable to this threat in the Southwestern Atlantic.
اظهر المزيد [+] اقل [-]Marine debris as a barrier: Assessing the impacts on sea turtle hatchlings on their way to the ocean
2018
Aguilera, M. | Medina-Suárez, M. | Pinós, J. | Liria-Loza, A. | Benejam, L.
Marine debris is dispersed worldwide and has a considerable impact on biodiversity. In this study, the effect of marine debris on the time needed for hatchling loggerheads to reach the ocean once they have emerged from the nest was investigated. After a preliminary census of marine debris on different beaches of Boa Vista Island, Cape Verde, a field test was carried out with four different scenarios: low density marine debris, medium density marine debris, high density marine debris, and a control scenario. The time that hatchlings required to cross the different scenarios was recorded (n = 232). The results showed that crawl times were affected by the different marine debris scenarios, with the “high density” scenario specifically showing a significant difference from the control, low density and medium density scenarios. This study provides information on the risks of marine debris for hatchling sea turtles and provides conservation recommendations to reduce this potential risk.
اظهر المزيد [+] اقل [-]Cu, Pb and Fe release from sulfide-containing tailings in seawater: Results from laboratory simulation of submarine tailings disposal
2018
Embile, Rodrigo F. | Walder, Ingar F. | Schuh, Christopher | Donatelli, Jenna Lee
Metal release from the deposition of sulfide-containing tailings in seawater was investigated using a batch reaction experiment inside a temperature and dissolved oxygen-controlled chamber. Two hundred grams of tailings from a porphyry Cu-Au and a sediment-hosted Cu deposit were submerged in 1.8 L synthetic seawater. The sulfides present in the porphyry Cu-Au tailings are pyrite (FeS2), chalcopyrite (CuFeS2) and bornite (Cu5FeS4) while in the sediment-hosted Cu tailings are bornite, chalcocite (Cu2S) and covellite (CuS). Galena occurs as a minor sulfide in both tailings. Pore water and overlying seawater samples were collected and analyzed for pH, redox potential and trace metals (Cu, Pb and Fe) concentration. Results show that there is very low Cu (10–40 μg/L), Pb (1–10 μg/L) and Fe (5–50 μg/L) released into solution throughout the course of 87 days. Long-term trace metal release from tailings in seawater is therefore theorized to be low and is a slow process.
اظهر المزيد [+] اقل [-]The effects of plastic bags presence on a macrobenthic community in a polluted estuary
2018
Clemente, Caroline C.C. | Paresque, Karla | Santos, Paulo J.P.
The damaging effects of marine debris on wildlife are often noted through the observation of animals that ingest and/or become entangled in debris. Yet, few studies have evaluated the effects of marine litter on benthic habitats. The aim of this study was to investigate if the presence of plastic bags has any effect on benthic macrofauna in an estuary located in an urban area in North-eastern Brazil. Biogeochemical and macrofauna samples were obtained from 10 different deposition locations (location factor), under, border and distant (treatment factor) from plastic bags. The results did not show any significant alterations in the biogeochemical parameters of the sediment due to treatment effect except for summed microphytobenthic pigments. The macrobenthic community structure responded to treatment. The greatest dissimilarity (34%) was between samples that were under and distant. Effects occurred despite the high dynamics of deposition-resuspension of plastic bags and the dominance of opportunistic species. Changes in community structure are a complex result of plastic bags effects on species ecological interactions in the polluted estuarine environment, attracting deposit feeders, diminishing suspension feeders and providing mechanical protection against predation by seabirds.
اظهر المزيد [+] اقل [-]T lymphocyte-proliferative responses of harbor seal (Phoca vitulina) peripheral blood mononuclear cells (PBMCs) exposed to pharmaceuticals in vitro
2018
Kleinert, Christine | Lacaze, Emilie | Fortier, Marlène | Hammill, Mike | De Guise, Sylvain | Fournier, Michel
The ubiquity of pharmaceuticals in the aquatic environment and the accumulation in organisms of lower trophic levels have been documented. The immunotoxicity of these xenobiotics has however been little investigated. This study assessed the effects of pharmaceuticals on the immune responses of harbor seal lymphocytes. Peripheral blood mononuclear cells isolated from harbor seal pups were exposed to varying concentrations of 17α-ethinyl estradiol (250–50,000μg/L), naproxen (500–100,000μg/L), carbamazepine (500–100,000μg/L), erythromycin (750–150,000μg/L) and binary mixtures thereof in vitro. All individual compounds and mixtures inhibited lymphocyte proliferation. Mixture effects were non-additive and predictive values overestimated the inhibition of proliferation. Male pups were more sensitive to erythromycin exposure. Comparison with the sensitivity of the 11B7501 cell line showed a higher sensitivity of pups to individual compounds and the inverse trend for mixtures. Based on our results, we hypothesize that pharmaceuticals may have the potential to interrupt immune functions in harbor seals.
اظهر المزيد [+] اقل [-]Status of vulnerable Cystoseira populations along the Italian infralittoral fringe, and relationships with environmental and anthropogenic variables
2018
Mancuso, F.P. | Strain, E.M.A. | Piccioni, E. | De Clerck, O. | Sarà, G. | Airoldi, L.
We analyzed the occurrence and status of infralittoral fringe populations of Cystoseira spp. (Fucales) at thirteen rocky sites around the Italian coastline, and explored the relationships with relevant environmental and anthropogenic variables. We found Cystoseira populations at 11 sites: most were scattered and comprised monospecific stands of C. compressa, and only 6 sites also supported sparse specimens of either C. amentacea var. stricta or C. brachycarpa. Coastal human population density, Chlorophyll a seawater concentrations, sea surface temperature, annual range of sea surface temperature and wave fetch explained most of the variation of the status of C. compressa. We hypothesize a generally unhealthy state of the Italian Cystoseira infralittoral fringe populations and identify multiple co-occurring anthropogenic stressors as the likely drivers of these poor conditions. Extensive baseline monitoring is needed to describe how Cystoseira populations are changing, and implement a management framework for the conservation of these valuable but vulnerable habitats.
اظهر المزيد [+] اقل [-]Screening of human and veterinary pharmaceuticals in estuarine waters: A baseline assessment for the Tejo estuary
2018
Reis-Santos, Patrick | Pais, Miguel | Duarte, Bernardo | Caçador, Isabel | Freitas, Andreia | Vila Pouca, Ana S. | Barbosa, Jorge | Leston, Sara | Rosa, João | Ramos, Fernando | Cabral, Henrique N. | Gillanders, Bronwyn M. | Fonseca, Vanessa F.
We investigated the presence of 66 human and veterinary pharmaceuticals from seven therapeutic groups in surface waters of the Tejo estuary. Collection sites covered the entire estuary and included areas near main river inflows and wastewater treatment outfalls, traversing urban, agriculture, aquaculture, and nature reserve areas. Detection of pharmaceuticals was performed via UHPLC-TOF-MS. Pharmaceuticals were found in all sites (32 different compounds in total). Antibiotics, β-blockers, antihypertensives and anti-inflammatories were the most frequently detected (>90%), with variation in concentrations reflecting the multifaceted nature of estuarine surroundings (accumulated site contamination between 15 and 351 ng L−1). Higher concentrations of antidepressant Sertraline (304 ng L−1), non-steroidal anti-inflammatory Diclofenac (51.8 ng L−1), lipid regulator Gemfibrozil (77.0 ng L−1), antihypertensive Ibersartan (161.9 ng L−1) or antibiotic Doxycycline (128.0 ng L−1), among others, though localized may potentially impact key estuarine functions or services. Ultimately, results provide a baseline for regulatory information and future biota evaluations.
اظهر المزيد [+] اقل [-]Effects of temperature and salinity on Ruppia sinensis seed germination, seedling establishment, and seedling growth
2018
Gu, Ruiting | Zhou, Yi | Song, Xiaoyue | Xu, Shaochun | Zhang, Xiaomei | Lin, Haiying | Xu, Shuai | Zhu, Shuyu
As typical submerged aquatic vegetation, Ruppia species are facing population reductions due to anthropogenic impacts. In this study, we investigated the effects of temperature and salinity on seed germination and seedling establishment of Ruppia sinensis seeds collected from northern China. The effects of seven salinities (0–50) and six water temperatures (0–30°C) on seed germination were investigated to identify the environmental conditions that could potentially limit survival and growth. We found that: 1) optimum seed germination was salinity 5 at 30°C; 2) high salinity (salinity 40–50) and low temperature (0°C) significantly inhibited seed germination; 3) seed germination with increasing temperature showed a bimodal pattern at suitable salinities (5–10); 4) storing seeds at high salinities (40–50) or low temperature (0°C) promoted germination after transferal to optimal germination conditions. These findings may serve as useful information for R. sinensis habitat establishment and restoration programs.
اظهر المزيد [+] اقل [-]Indigenous microbial communities along the NW Portuguese Coast: Potential for hydrocarbons degradation and relation with sediment contamination
2018
Gouveia, Vanessa | Almeida, C. Marisa R. | Almeida, Tania | Teixeira, Catarina | Mucha, Ana P.
Hydrocarbon degradation (HD) potential by autochthonous microorganisms in the coastal sediments of the NW area of Portugal (coastal sandy beaches and estuaries of the rivers Minho and Douro) was evaluated, investigating if water and sediment contamination/characteristics influence it. Sediments were characterized for microbial abundance (by DAPI), HD microorganisms' abundance (by MPN), microbial community structure (by ARISA), hydrocarbons (by FTIR and SPME-GC–MS), hazardous and noxious substances (SPME-GC–MS) and metals (by AAS). To our knowledge, this is the first time all these pollutants, including the selected HNS, were measured simultaneously in sediments of the selected coastal area. Higher contaminants concentrations were, generally, registered in Douro samples. A clear differentiation of the microbial community structure between beaches and estuaries was observed, as well as, between Douro and Minho river estuaries. BIO-ENV analysis indicated both sediment characteristics (e.g. OM content) and contaminants presence/concentrations (e.g. tetrachloroethylene presence) affected the structure of the microbial community along the studied areas. In all the selected sites, the characterized autochthonous microbial communities showed potential for hydrocarbons degradation, with HD microorganisms being found in all collected sediments. These microorganisms can be a valuable asset to recover contaminated areas, but sediment characteristics and contaminants presence/levels need to be taken into account as they can affect their bioremediation potential and the success of their application as biotechnological tool.
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