Affiner votre recherche
Résultats 1661-1670 de 4,929
Live fast, die young: Behavioural and physiological impacts of light pollution on a marine fish during larval recruitment
2019
O'Connor, J.J. | Fobert, E.K. | Besson, M. | Jacob, H. | Lecchini, D.
Artificial light at night (ALAN) is a recently acknowledged form of anthropogenic pollution of growing concern to the biology and ecology of exposed organisms. Though ALAN can have detrimental effects on physiology and behaviour, we have little understanding of how marine organisms in coastal areas may be impacted. Here, we investigated the effects of ALAN exposure on coral reef fish larvae during the critical recruitment stage, encompassing settlement, metamorphosis, and post-settlement survival. We found that larvae avoided illuminated settlement habitats, however those living under ALAN conditions for 10 days post-settlement experienced changes in swimming behaviour and higher susceptibility to nocturnal predation. Although ALAN-exposed fish grew faster and heavier than control fish, they also experienced significantly higher mortality rates by the end of the experimental period. This is the first study on the ecological impacts of ALAN during the early life history of marine fish.
Afficher plus [+] Moins [-]Assessment of input of organic micropollutants and microplastics into the Baltic Sea by urban waters
2019
Bollmann, Ulla E. | Simon, Marta | Vollertsen, Jes | Bester, Kai
We assess how different micropollutants and microplastics, connected to wastewater are introduced into the Baltic Sea. The relevance of untreated wastewater, treated wastewater, treated and untreated rain runoff, as well as combined sewer overflow (CSO), is assessed in respect to mass balance, as well as relative inflows of micropollutants and -plastics into the Baltic Sea. To achieve this, modelling based on data on exemplary sewer systems and measured micropollutant concentrations in the single sources were used. Most compounds reach the receiving Baltic Sea via treated wastewater. A few exceptions are compounds that are removed to a very high extent in wastewater treatment plants. For these compounds, the emissions with stormwater (e.g., terbutryn) or untreated wastewater (e.g., triclosan) are dominating. Additionally, compounds that are discharged with the water that is running off urban surfaces are introduced into marine areas via rain runoff. These data are used to forecast a total mass load and concentrations that can be expected in the Baltic Sea. Massloads are expected to be between 0.1 and 5.9 t/a for triclosan and TCPP (tris (2-chloropropyl) phosphate) and 0.2 t/a for microplastic particles. The expected concentrations in open Baltic Sea waters range from 0.01 to 26 ng/L.
Afficher plus [+] Moins [-]Spatial variation of trace element concentration and contamination assessment in the coral reef sediments of Lakshadweep Archipelago, Indian Ocean
2019
Joy, Anu | P P, Anoop | R, Rajesh | Mathew, Jose | Mathew, Angel | Gopinath, Anu
Surface sediments were collected from the shore and lagoons of Kavaratti, Kadmat and Agatti islands of Lakshadweep Archipelago and analysed for trace element concentration. The sediment contamination was assessed on the basis of geochemical, biological hazard and ecological risk indices. Except Cd and Pb, all the other trace elements selected for the study were below the contamination level. Compared to Kadmat, Kavaratti and Agatti were more polluted and the pollution was pronounced in lagoons than shore. Population pressure, untreated sewage, diesel based power generation, shipping and tourism activities contribute to sediment contamination. Statistical analysis revealed the association of trace elements with sedimentary characteristics due to anthropogenic sources.
Afficher plus [+] Moins [-]The distribution of sediment bacterial community in mangroves across China was governed by geographic location and eutrophication
2019
Tong, Tianli | Li, Ruili | Wu, Sijie | Xie, Shuguang
Bacterial community is an important component of mangrove ecosystem and can participate in the cycling of elements and promote plant growth. However, the biogeographic distribution pattern of mangrove bacterial community and the associated factors remain poorly known. The present study explored the biogeographic distribution of sediment bacterial community in six mangroves across China. At each mangrove, sediments were collected from both Avicennia marina-planted zones and intertidal mudflats. The community abundance, richness, diversity and structure of sediment bacteria differed greatly among mangrove wetlands. Plantation showed a positive influence on sediment bacterial abundance, richness and diversity. Proteobacteria was the largest bacterial phylum in sediments. The biogeographic distribution of bacterial community in mangroves across China was driven by the variables associated with the wetland trophic status as well as other physicochemical factors (e.g., salinity).
Afficher plus [+] Moins [-]Trace element concentrations, ecological and health risk assessment in sediment and marine fish Otolithes ruber in Oman Sea, Iran
2019
Sadeghi, Parvin | Loghmani, Mehran | Afsa, Elahe
This study aimed to investigate the concentration of Cd, Ni, Cr, Pb and As in the tissues of Otolithes ruber and surface sediments in the Oman Sea. Trace element concentrations were analyzed by flame atomic absorption spectrophotometer (FAAS) for ecological and health risk assessment. The results showed a significant difference in trace element concentrations of the liver, muscle and sediments between different stations (p < 0.05). Potential ecological risk index (PER) indicated very high risk for Cd at all stations. Estimated daily intake (EDI) for consumption of Otolithes ruber for Cr, Pb and As was lower than tolerable daily intake (TDI). The mean target hazard quotient (THQ) of Cd and Ni were higher than 1 at all stations. Target cancer risk (TR) for Ni and As were higher than the acceptable value range at all stations. Accordingly, the risk of cancer due to the long-term consumption of this fish can be concerned.
Afficher plus [+] Moins [-]Oil behavior in sea ice: Changes in chemical composition and resultant effect on sea ice dielectrics
2019
Desmond, Durell S. | Saltymakova, Diana | Neusitzer, Thomas D. | Firoozy, Nariman | Isleifson, Dustin | Barber, David G. | Stern, Gary A.
There has been increasing urgency to develop methods for detecting oil in sea ice owing to the effects of climate change in the Arctic. A multidisciplinary study of crude oil behavior in a sea ice environment was conducted at the University of Manitoba during the winter of 2016. In the experiment, medium-light crude oil was injected underneath young sea ice in a mesocosm. The physical and thermodynamic properties of the oil-infiltrated sea ice were monitored over a three-week time span, with concomitant analysis of the oil composition using analytical instrumentation. A resonant perturbation technique was used to measure the oil dielectric properties, and the contaminated sea ice dielectric properties were modeled using a mixture model approach. Results showed that the interactions between the oil and sea ice altered their physical and thermodynamic properties. These changes led to an overall decrease in sea ice dielectrics, potentially detectable by remote sensing systems.
Afficher plus [+] Moins [-]VanA-type vancomycin-resistant Enterococcus faecium ST1336 isolated from mussels in an anthropogenically impacted ecosystem
2019
Sacramento, Andrey G. | Fernandes, Miriam R. | Sellera, Fábio P. | Dolabella, Silvio S. | Zanella, Rosemeire C. | Cerdeira, Louise | Lincopan, Nilton
We report the occurrence and genomic features of multidrug-resistant vancomycin-resistant Enterococcus faecium vanA belonging to a novel sequence type (designated ST1336), carrying a Tn1546-like element, in marine brown mussels (Perna perna) from anthropogenically affected coastal waters of the Atlantic coast of Brazil, highlighting a potential source of dissemination for related ecosystems, with additional consequences for seafood safety and quality.
Afficher plus [+] Moins [-]Assessment of metal contamination in Arabian/Persian Gulf fish: A review
2019
Cunningham, Patricia A. | Sullivan, Elizabeth E. | Everett, Kibri H. | Kovach, Samuel S. | Rajan, Anbiah | Barber, Mary C.
Metal contamination in fish is a concern worldwide, including in the Arabian/Persian Gulf region. This review summarizes the findings from 55 papers about metal concentrations in Gulf fish. Metal concentrations in muscle tissue were screened against the most recent maximum allowable levels (MALs) for fish in international commerce. We identified metals, fish species, and locations where concentrations exceeded the MALs. For some metals, recent MALs have been set to lower concentrations as more toxicological data have become available. Mean fish tissue concentrations exceeded the MAL in 13% (arsenic), 76% (cadmium), 56% (lead), and 10% (mercury) of species means. We identified 13 fish species with the potential to serve as bioindicators of metal contamination for use in four Gulf habitats: pelagic, benthopelagic, demersal, and coral reefs. Recommendations are provided for a regional approach to improve consistency of sampling, data analysis and reporting of metal concentrations in Gulf fish.
Afficher plus [+] Moins [-]Plastic-derived contaminants in sediments from the coastal zone of the southern Baltic Sea
2019
Lubecki, Ludwik | Kowalewska, Grażyna
Plastics may leach out harmful chemicals, such as plastic additives and monomers, to the environment. This study focused on three intrinsic plastic-derived contaminants, viz. bis(2-ethylhexyl) phthalate (DEHP), bisphenol A (BPA), and styrene, based on surface (0–5 cm) sediment samples taken from transition areas located in the human-impacted coastal zone of the southern Baltic Sea. The concentrations of DEHP in the sediments from the Gulf of Gdańsk and the Szczecin Lagoon ranged from 38 to 228 ng/g d.w. and from 494 to 807 ng/g d.w., respectively. The levels of sedimentary BPA varied from <1 to 32 ng/g d.w., whereas styrene was not detected in any of the samples studied. Compared to worldwide data, the levels of plastic-derived contaminants in the sediments from the Gulf of Gdańsk and the Szczecin Lagoon were generally not high. However, according to sediment quality guidelines, some adverse environmental effects are probable.
Afficher plus [+] Moins [-]Mid-long term oil spill forecast based on logistic regression modelling of met-ocean forcings
2019
Chiri, Helios | Abascal, Ana Julia | Castanedo, Sonia | Medina, Raul
Past major oil spill disasters, such as the Prestige or the Deepwater Horizon accidents, have shown that spilled oil may drift across the ocean for months before being controlled or reaching the coast. However, existing oil spill modelling systems can only provide short-term trajectory simulations, being limited by the typical met-ocean forecast time coverage. In this paper, we propose a methodology for mid-long term (1–6 months) probabilistic predictions of oil spill trajectories, based on a combination of data mining techniques, statistical pattern modelling and probabilistic Lagrangian simulations. Its main features are logistic regression modelling of wind and current patterns and a probabilistic trajectory map simulation. The proposed technique is applied to simulate the trajectory of drifting buoys deployed during the Prestige accident in the Bay of Biscay. The benefits of the proposed methodology with respect to existing oil spill statistical simulation techniques are analysed.
Afficher plus [+] Moins [-]