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An adaptive grid to improve the efficiency and accuracy of modelling underwater noise from shipping Texte intégral
2018
Trigg, Leah E. | Chen, Feng | Shapiro, Georgy I. | Ingram, Simon N. | Embling, Clare B.
Underwater noise pollution from shipping is a significant ecological concern. Acoustic propagation models are essential to predict noise levels and inform management activities to safeguard ecosystems. However, these models can be computationally expensive to execute. To increase computational efficiency, ships are spatially partitioned using grids but the cell size is often arbitrary. This work presents an adaptive grid where cell size varies with distance from the receiver to increase computational efficiency and accuracy. For a case study in the Celtic Sea, the adaptive grid represented a 2 to 5 fold increase in computational efficiency in August and December respectively, compared to a high resolution 1 km grid. A 5 km grid increased computational efficiency 5 fold again. However, over the first 25 km, the 5 km grid produced errors up to 13.8 dB compared to the 1 km grid, whereas, the adaptive grid generated errors of less than 0.5 dB.
Afficher plus [+] Moins [-]Distribution pattern of persistent organic pollutants in aquatic ecosystem at the Rosetta Nile branch estuary into the Mediterranean Sea, North of Delta, Egypt Texte intégral
2018
Abbassy, Moustafa Mohamed Saleh
The objective of this study was to evaluate the distribution pattern of persistent organic pollutants in water, sediment and aquatic biota represented by Oreochromis niloticus and Donax trunculus at the Rosetta Nile branch estuary. α-HCH, p,p′-DDE and polychlorinated biphenyls were the predominant compounds detected at ranges of 0.54–4.90 ng/l water, 0.75–2.41 ng/g, d. wt. sediment and 2.19–28.11 ng/g, fresh wt. biota. β and γ-HCHs, endosulfan compounds, heptachlor and heptachlor epoxide were at low detection frequencies. Totally, the organochlorine pollutants were at high levels and abundances in Donax spp. than in Tilapia spp. followed by sediment and water. These levels were ranged between lower and higher than those found by the other studies established in Egypt, and well below its tolerable residue levels in fish. A correlation was found for the quantified pollutants between water, sediment and biota. This is clearly reflecting the bioaccumulation properties of these compounds.
Afficher plus [+] Moins [-]Distribution, sources, and ecological risk assessment of quinotone antibiotics in the surface sediments from Jiaozhou Bay wetland, China Texte intégral
2018
Liu, Ke | Yin, Xiaofei | Zhang, Daolai | Yan, Dongyun | Cui, Lijuan | Zhu, Zhigang | Wen, Li
The distribution, sources, and risk assessment of eight quinotone antibiotics (QNs) in the surface sediments from the wetland in Jiaozhou Bay were investigated. The results showed that QNs were detected in all samples, and the total concentrations of QNs in the sediments ranged from 0.276 to 5.229ng/g. The highest concentration occurred at the entrance to the Yang River wetland. Principal component analysis suggested that the QNs mainly originated from sewage discharges from hospitals, human and aquaculture industries. Risk assessment, based on risk quotients, indicated the current ofloxacin level might be a medium risk level, while other QNs were all low risk. Nevertheless, there should still be concerns due to high consumption of QNs by human beings, animals, and aquatic organisms in the wetland. This investigation provides baseline data that the government can use as a reference guide to control QNs residues in Jiaozhou Bay wetland.
Afficher plus [+] Moins [-]Spatial variability in the concentrations of metals in beached microplastics Texte intégral
2018
Vedolin, M.C. | Teophilo, C.Y.S. | Turra, A. | Figueira, R.C.L.
Heavy metals and microplastics have been considered as threats to the marine environment and the interactions between these two pollutants are poorly understood. This study investigates the interactions between metals adsorbed in pellets collected randomly from 19 beaches along the coast of São Paulo State in southeastern Brazil, comparing these levels with those in virgin pellets. The samples were analyzed for Al, Cr, Cu, Fe, Mn, Sn, Ti and Zn by inductively coupled plasma optical emission spectroscopy (ICP-OES). The polymers were solubilized via acid digestion. The highest levels occurred with Fe (227.78mgkg−1 - Itaguaré) and Al (45.27mgkg−1 - Guaraú) in the same areas, which are closer to the Port of Santos. The metal adsorption on pellets collected is greater than that on virgin pellets. In this context, pellets can be considered to be a carrier for the transport of metals in the environment, even in small quantities.
Afficher plus [+] Moins [-]RNA-seq analysis reveals the significant effects of different light conditions on oil degradation by marine Chlorella vulgaris Texte intégral
2018
Li, Jingjing | Chen, Qingguo | Bao, Bo | Liu, Mei | Bao, Mutai | Liu, Junzhi | Mu, Jun
Marine Chlorella vulgaris, an efficient hydrocarbon-degrading organism, is easily affected by light. In this study, we investigated the direct effects of different light conditions on crude oil degradation by C. vulgaris and its crude enzyme. Under 12 h illumination, the crude enzyme improved hydrocarbon removal by 39.36%, whereas the addition of the enzyme and C. vulgaris increased the degradation rate by 121.73%. Conversely, the addition of enzyme under heterotrophic condition was negatively related to oil degradation by C. vulgaris, and the degradation rate decreased from 74.32% to 48.65% and further reduced by 34.54%. The results of RNA sequencing analysis suggested that hydrocarbons removal was attributed to C. vulgaris metabolism in heterotrophic physiological state. While enhanced removal efficiency of hydrocarbons was achieved in mixotrophic physiological state due to the coupling of C. vulgaris metabolism with photocatalytic oxidation. Functional enzymes played key roles in photocatalysis and biodegradation processes.
Afficher plus [+] Moins [-]Exceptional biodiversity of the cryptofaunal decapods in the Chagos Archipelago, central Indian Ocean Texte intégral
2018
Head, Catherine E.I. | Bonsall, Michael B. | Jenkins, Tom L. | Koldewey, Heather | Pratchett, Morgan S. | Taylor, Michelle L. | Rogers, Alex D.
The Chagos Archipelago is geographically remote and isolated from most direct anthropogenic pressures. Here, we quantify the abundance and diversity of decapod crustaceans inhabiting dead coral colonies, representing a standardised microhabitat, across the Archipelago. Using morphological and molecular techniques we recorded 1868 decapods from 164 nominal species within 54 dead coral colonies, but total species estimates (Chao1 estimator) calculate at least 217 species. Galatheids were the most dominant taxa, though alpheids and hippolytids were also very abundant. 32% of species were rare, and 46% of species were found at only one atoll. This prevalence of rarer species has been reported in other cryptofauna studies, suggesting these assemblages maybe comprised of low-abundance species. This study provides the first estimate of diversity for reef cryptofauna in Chagos, which will serve as a useful baseline for global comparisons of coral reef biodiversity.
Afficher plus [+] Moins [-]Spreading of drill cuttings and sediment recovery of three exploration wells of different ages, SW Barents Sea, Norway Texte intégral
2018
Junttila, Juho | Dijkstra, Noortje | Aagaard-Sørensen, Steffen
Spreading of drill cuttings and sediment recovery of three exploration wells of different ages, SW Barents Sea, Norway Texte intégral
2018
Junttila, Juho | Dijkstra, Noortje | Aagaard-Sørensen, Steffen
Five stations (≤250 m from the well heads) from three exploration wells of different ages from the SW Barents Sea were studied to investigate the spreading of drill cuttings and sediment quality. Two of the wells were drilled before the restriction of use of oil-based drilling fluids (1993). Elevated concentrations of Ba were found in sediments near all the wells with the highest concentrations at ≤60 m from the well head. The thickness of drill cutting layers was between >20 cm (well head) and 2 cm (250 m from the well head). The sediment quality varied from very bad (oldest well) to background (normal) (newer wells). Regulations led to better sediment quality. Metal concentrations from the oldest well suggested that the top 4 cm of the core represents sediment recovery. However, Ba concentrations of the top sediment layer at all the stations of the three wells indicate no physical recovery.
Afficher plus [+] Moins [-]Spreading of drill cuttings and sediment recovery of three exploration wells of different ages, SW Barents Sea, Norway Texte intégral
2018
Junttila, Juho | Dijkstra, Noortje | Sørensen, Steffen Aagaard
Accepted manuscript version, licensed <a href=http://creativecommons.org/licenses/by-nc-nd/4.0/> CC BY-NC-ND 4.0.</a> Published version available at <a href=https://doi.org/10.1016/j.marpolbul.2018.06.064>https://doi.org/10.1016/j.marpolbul.2018.06.064. </a> | Five stations (≤250 m from the well heads) from three exploration wells of different ages from the SW Barents Sea were studied to investigate the spreading of drill cuttings and sediment quality. Two of the wells were drilled before the restriction of use of oil-based drilling fluids (1993). Elevated concentrations of Ba were found in sediments near all the wells with the highest concentrations at ≤60 m from the well head. The thickness of drill cutting layers was between > 20 cm (well head) and 2 cm (250 m from the well head). The sediment quality varied from very bad (oldest well) to background (normal) (newer wells). Regulations led to better sediment quality. Metal concentrations from the oldest well suggested that the top 4 cm of the core represents sediment recovery. However, Ba concentrations of the top sediment layer at all the stations of the three wells indicate no physical recovery
Afficher plus [+] Moins [-]Residual effects of treated effluent diversion on a seaweed farm in a tidal strait using a multi-nested high-resolution 3-D circulation-dispersal model Texte intégral
2018
Uchiyama, Yusuke | Zhang, Xu | Suzue, Yota | Kosako, Taichi | Miyazawa, Yasumasa | Nakayama, Akihiko
A high-resolution 3-D model was developed to assess the impact of a diversion outfall at the Tarumi Sewage Treatment Plant (TSTP) on an adjacent seaweed farm in Osaka Bay, Japan. The model was extensively validated to ensure a reasonable agreement with in situ observations. The western part of the farm is largely influenced by tidal currents, whereas the eastern area is mainly affected by subtidal residual currents that are primarily due to surface wind stress. The released effluent is transported by counterclockwise residual circulation formed off the TSTP. The model reveals that the diversion adequately suppresses the influence on the farm. While the instantaneous effluent concentration is diminished by about 50%, the effluent accumulated on the farm decreased from 2.83 × 104 m3 to 2.01 × 104 m3 due to the diversion, demonstrating an approximately 28% reduction of the effluent from the TSTP by the diversion outfall.
Afficher plus [+] Moins [-]Challenges in rendering Coral Triangle habitat richness in remotely sensed habitat maps: The case of Bunaken Island (Indonesia) Texte intégral
2018
Ampou, Eghbert Elvan | Ouillon, Sylvain | Andréfouët, Serge
The Coral Triangle is the epicenter of marine biodiversity, yet the numbers of habitats that can be found on coral reefs remain poorly described. First surveys for habitat mapping in Indonesia revealed a high number of habitats (>150) even for structurally simple reefs. To be able to represent all these habitats, typical habitat mapping procedures and performances are poorly effective even using very high resolution satellite images. Using Bunaken Island (North Sulawesi, Indonesia) as a case study, we devised a way to maintain all the in situ habitat information in remote sensing habitat map products without loss and with mapping procedures based on photo-interpretation. The result is a product which is consistent with a per-polygon fuzzy classification. As such, it is a complex product that meets our habitat representation goal, but its complexity can also limit its immediate use by managers and conservation planners when analyses per habitat are needed.
Afficher plus [+] Moins [-]Ingestion of microplastics and natural fibres in Sardina pilchardus (Walbaum, 1792) and Engraulis encrasicolus (Linnaeus, 1758) along the Spanish Mediterranean coast Texte intégral
2018
Compa, Montserrat | Ventero, Ana | Iglesias, Magdalena | Deudero, Salud
Ingestion of microplastics and natural fibres in Sardina pilchardus (Walbaum, 1792) and Engraulis encrasicolus (Linnaeus, 1758) along the Spanish Mediterranean coast Texte intégral
2018
Compa, Montserrat | Ventero, Ana | Iglesias, Magdalena | Deudero, Salud
The ingestion of microplastics and natural fibres (<5 mm) was assessed for two commercial fish species in the western Mediterranean Sea: Sardina pilchardus and Engraulis encrasicolus. Gastrointestinal tracts from 210 individuals from 14 stations were examined with 14.28–15.24% of the small pelagic fish S. pilchardus and E. encrasicolus having ingested microplastics and natural fibres. A latitudinal increase in condition index (Fulton's K) of S. pilchardus gave an indication that larger individuals with better physical condition are less likely to ingest microplastics and natural fibres. Fibres were the most frequent particle type (83%) and Fourier Transform Infrared spectroscopy (FT-IR) analysis indicated polyethylene terephthalate was the most common microplastics material (30%). Results from this study show that both microplastics and natural fibres of anthropogenic origin are common throughout the pelagic environment along the Spanish Mediterranean coast.
Afficher plus [+] Moins [-]Ingestion of microplastics and natural fibres in Sardina pilchardus (Walbaum, 1792) and Engraulis encrasicolus (Linnaeus, 1758) along the Spanish Mediterranean coast Texte intégral
2018
Compa, Montserrat | Ventero, Ana | Iglesias, Magdalena | Deudero, Salud
The ingestion of microplastics and natural fibres (< 5 mm) was assessed for two commercial fish species in the western Mediterranean Sea: Sardina pilchardus and Engraulis encrasicolus. Gastrointestinal tracts from 210 individuals from 14 stations were examined with 14.28–15.24% of the small pelagic fish S. pilchardus and E. encrasicolus having ingested microplastics and natural fibres. A latitudinal increase in condition index (Fulton's K) of S. pilchardus gave an indication that larger individuals with better physical condition are less likely to ingest microplastics and natural fibres. Fibres were the most frequent particle type (83%) and Fourier Transform Infrared spectroscopy (FT-IR) analysis indicated polyethylene terephthalate was the most common microplastics material (30%). Results from this study show that both microplastics and natural fibres of anthropogenic origin are common throughout the pelagic environment along the Spanish Mediterranean coast | M. Compa is the recipient of a FPI Fellowship from Conselleria d'Innovació, Recerca i Turisme of the regional Government of the Balearic Islands co-financed by the European Social Fund as part of the FSE 2014–2020 operational program. This study was partially funded by Ajuts per dur a terme Accions Especials de Recerca i Desenvolupament 2015–2016 del Govern de les Illes Balears, Ref: 17/2015. Additional appreciation to Antonio Esteban for coordinating the sample collection and special thanks to Tamara Gajst, Tine Bizjak and Arto Koistinen from SIB Labs at the University of Finland. The MEDIAS surveys have been co-funded by the European Union through the European Maritime and Fisheries Fund (EMFF) within the National Program of collection, management and use of data in the fisheries sector and support for scientific advice regarding the Common Fisheries Policy. In addition, this study was partially funded by the European Commission DG Environment project: “Support Mediterranean Member States towards coherent and Coordinated Implementation of the second phase of the MSFD – MEDCIS” with Grant no. 11.0661/2016/748067/SUB/ENV.C2. | Peer reviewed
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