خيارات البحث
النتائج 1131 - 1140 من 4,042
Localised and limited impact of a dredging operation on coral cover in the northwestern lagoon of New Caledonia النص الكامل
2016
Adjeroud, Mehdi | Gilbert, Antoine | Facon, Mathilde | Foglia, Marion | Moreton, Benjamin | Heintz, Tom
We report here an interannual survey (2006–2012) of coral cover in the northwestern lagoon of New Caledonia, to assess the impact of an important dredging operation (August 2008–February 2010) associated with the construction of the largest nickel mining site in the Pacific. A BACI (Before-After Control-Impact) analysis failed to detect any significant interaction between period (before, during, and after dredging) and the category of the stations (impact vs. control). Among the 31 stations surveyed, only seven showed decreasing coral cover during the study period, mainly due to a decline in Acroporidae. However, the relationship between the dredging and this decrease was highly plausible only for one station, situated 0.9km from the dredging site. High hydrodynamism in the study area, the abundance of resistant corals and efficient protective measures during the dredging operation might explain these localised and limited impacts.
اظهر المزيد [+] اقل [-]Distribution and characteristics of methylmercury in surface sediment in Minamata Bay النص الكامل
2016
Matsuyama, Akito | Yano, Shinichiro | Hisano, Akihiro | Kindaichi, Michiaki | Sonoda, Ikuko | Tada, Akihide | Akagi, Hirokatsu
This study was carried out to evaluate the present-day chemical properties of methylmercury in surface sediment in Minamata Bay where a dredging project was completed 28years ago. Present-day sediment from Minamata Bay consists of sandy silt, and the average loss-on-ignition in surface sediment was 7.0±2.3%. The average methylmercury concentrations in the upper sediment layers were significantly higher than those in the lower sediment layers. Currently, the concentrations in sediments in Minamata Bay do not exceed the Japanese regulatory standard value for mercury. The average concentration of methylmercury in Minamata Bay surface sediment was 1.74±1.0ng/g on a dry weight basis (n=107). The methylmercury concentration in Minamata Bay surface sediment was almost 16 times higher than that in surface sediment from Isahaya Bay surface sediment, which was 0.11±0.045ng/g on a dry weight basis (n=5).
اظهر المزيد [+] اقل [-]Master Plan Jakarta, Indonesia: The Giant Seawall and the need for structural treatment of municipal waste water النص الكامل
2016
van der Wulp, Simon A. | Dsikowitzky, Larissa | Hesse, Karl Jürgen | Schwarzbauer, Jan
In order to take actions against the annual flooding in Jakarta, the construction of a Giant Seawall has been proposed in the Master Plan for National Capital Integrated Coastal Development. The seawall provides a combination of technical solutions against flooding, but these will heavily modify the mass transports in the near-coastal area of Jakarta Bay. This study presents numerical simulations of river flux of total nitrogen and N,N-diethyl-m-toluamide, a molecular tracer for municipal waste water for similar scenarios as described in the Master Plan. Model results demonstrate a strong accumulation of municipal wastes and nutrients in the planned reservoirs to extremely high levels which will result in drastic adverse eutrophication effects if the treatment of municipal waste water is not dealt with in the same priority as the construction of the Giant Seawall.
اظهر المزيد [+] اقل [-]Molecular biodiversity of Red Sea demosponges النص الكامل
2016
Erpenbeck, Dirk | Voigt, Oliver | Al-Aidaroos, Ali M. | Berumen, Michael L. | Büttner, Gabriele | Catania, Daniela | Guirguis, Adel Naguib | Paulay, Gustav | Schätzle, Simone | Wörheide, Gert
Sponges are important constituents of coral reef ecosystems, including those around the Arabian Peninsula. Despite their importance, our knowledge on demosponge diversity in this area is insufficient to recognize, for example, faunal changes caused by anthropogenic disturbances. We here report the first assessment of demosponge molecular biodiversity from Arabia, with focus on the Saudi Arabian Red Sea, based on mitochondrial and nuclear ribosomal molecular markers gathered in the framework of the Sponge Barcoding Project. We use a rapid molecular screening approach on Arabian demosponge collections and analyze results in comparison against published material in terms of biodiversity. We use a variable region of 28S rDNA, applied for the first time in the assessment of demosponge molecular diversity. Our data constitutes a solid foundation for a future more comprehensive understanding of sponge biodiversity of the Red Sea and adjacent waters.
اظهر المزيد [+] اقل [-]Esterase activity (EA), total oxidant status (TOS) and total antioxidant capacity (TAC) in gills of Mytilus galloprovincialis exposed to pollutants: Analytical validation and effects evaluation by single and mixed heavy metal exposure النص الكامل
2016
Franco Vidal, Lorena | Romero, Diego | García-Navarro, José A. | Teles, Mariana | Tvarijonaviciute, Asta
The aims of the present study were to optimize and validate methods for esterase activity (EA), total oxidant status (TOS) and total antioxidant capacity (TAC) determination in mussel' gills, and to establish the relationships between these biomarkers and Pb, Cd and Cu pollution, in single form and ternary mixture. Two different buffers for sample homogenization, the need of ultracentrifugation, and analytical validation were evaluated. Coefficients of variation, when buffer without additives and ultracentrifugation were used, were <15%, and recovery were 97%–109% in all cases. The EA response tends to decrease with treatments, TOS decreased significantly in Cd and ternary groups, while TAC tended to increase in treatments with Pb, Cd and ternary groups. In conclusion, the methods for EA, TOS and TAC measurements in gills of mussel were precise and accurate and could be interesting resources in biomonitoring programmes.
اظهر المزيد [+] اقل [-]Environmental assessment of pesticides in the Mondego River Estuary (Portugal) النص الكامل
2016
Cruzeiro, Catarina | Rocha, Eduardo | Pardal, Miguel Ângelo | Rocha, Maria João
The Mondego River estuary, located on the North Atlantic Ocean Ecoregion, is a basin affected by agricultural run-off with increasing signs of eutrophication. We evaluated the amounts and distribution of 56 priority pesticides belonging to distinct categories (insecticides, herbicides and fungicides). Temporal trends were considered and a total of 42 surface water samples were collected between 2010 and 2011. More than 55% of the GC–MS/MS-quantified pesticides were above the maximum amounts established by the European Directives (98/83/EC and 2013/39/EU). Based on the concentration addition (CA) and independent action (IA) models, we used a two-tiered approach to assess the hazard of the pesticide mixture, at the maximum concentration found, reflecting a potential risk. Short-term exposure using Artemia salina indicated a significant toxic effect where the locomotion of the animals was clearly affected.
اظهر المزيد [+] اقل [-]A review of crustacean sensitivity to high amplitude underwater noise: Data needs for effective risk assessment in relation to UK commercial species النص الكامل
2016
Edmonds, Nathan J. | Firmin, Christopher J. | Goldsmith, D. (Denise) | Faulkner, Rebecca C. | Wood, Daniel T.
High amplitude anthropogenic noise is associated with adverse impacts among a variety of organisms but detailed species-specific knowledge is lacking in relation to effects upon crustaceans. Brown crab (Cancer pagurus), European lobster (Homarus gammarus) and Norway lobster (Nephrops norvegicus) together represent the most valuable commercial fishery in the UK (Defra, 2014). Critical evaluation of literature reveals physiological sensitivity to underwater noise among N. norvegicus and closely related crustacean species, including juvenile stages. Current evidence supports physiological sensitivity to local, particle motion effects of sound production in particular. Derivation of correlative relationships between the introduction of high amplitude impulsive noise and crustacean distribution/abundance is hindered by the coarse resolution of available data at the present time. Future priorities for research are identified and argument for enhanced monitoring under current legislative frameworks outlined.
اظهر المزيد [+] اقل [-]Spatial variability and response to anthropogenic pressures of assemblages dominated by a habitat forming seaweed sensitive to pollution (northern coast of Alboran Sea) النص الكامل
2016
Bermejo, Ricardo | de la Fuente, Gina | Ramírez-Romero, Eduardo | Vergara, Juan J. | Hernández, Ignacio
Spatial variability and response to anthropogenic pressures of assemblages dominated by a habitat forming seaweed sensitive to pollution (northern coast of Alboran Sea) النص الكامل
2016
Bermejo, Ricardo | de la Fuente, Gina | Ramírez-Romero, Eduardo | Vergara, Juan J. | Hernández, Ignacio
The Cystoseira ericaefolia group is conformed by three species: C. tamariscifolia, C. mediterranea and C. amentacea. These species are among the most important habitat forming species of the upper sublittoral rocky shores of the Mediterranean Sea and adjacent Atlantic coast. This species group is sensitive to human pressures and therefore is currently suffering important losses. This study aimed to assess the influence of anthropogenic pressures, oceanographic conditions and local spatial variability in assemblages dominated by C. ericaefolia in the Alboran Sea. The results showed the absence of significant effects of anthropogenic pressures or its interactions with environmental conditions in the Cystoseira assemblages. This fact was attributed to the high spatial variability, which is most probably masking the impact of anthropogenic pressures. The results also showed that most of the variability occurred on at local levels. A relevant spatial variability was observed at regional level, suggesting a key role of oceanographic features in these assemblages.
اظهر المزيد [+] اقل [-]Spatial variability and response to anthropogenic pressures of assemblages dominated by a habitat forming seaweed sensitive to pollution (northern coast of Alboran Sea) النص الكامل
2016
Bermejo-Lacida, Ricardo | de la Fuente, Gina | Ramírez-Romero, Eduardo | Vergara, Juan J. | Hernández, Ignacio
El copyright de esta publicación pertenece al editor en exclusiva, no está permitido el acceso al texto completo. | The Cystoseira ericaefolia group is conformed by three species: C. tamariscifolia, C. mediterranea and C. amentacea. These species are among the most important habitat forming species of the upper sublittoral rocky shores of the Mediterranean Sea and adjacent Atlantic coast. This species group is sensitive to human pressures and therefore is currently suffering important losses. This study aimed to assess the influence of anthropogenic pressures, oceanographic conditions and local spatial variability in assemblages dominated by C. ericaefolia in the Alboran Sea. The results showed the absence of significant effects of anthropogenic pressures or its interactions with environmental conditions in the Cystoseira assemblages. This fact was attributed to the high spatial variability, which is most probably masking the impact of anthropogenic pressures. The results also showed that most of the variability occurred on at local levels. A relevant spatial variability was observed at regional level, suggesting a key role of oceanographic features in these assemblages. | Contract OT 2010/102 between the University of Cadiz and the Environmental Division of the Autonomic Government (Junta de Andalucía) Sapanish national project CTM2011-24482 (SEA-LIVE); R. Bermejo holds a FPU fellowship of the Spanish Ministry of Education. European Commission (OCEAN-CERTAIN, FP7-ENV- 2013-6.1-1; no: 603773).
اظهر المزيد [+] اقل [-]Marine protected area design patterns in the Mediterranean Sea: Implications for conservation النص الكامل
2016
Rodríguez-Rodríguez, D. | Rodríguez, J. | Blanco, J.M. | Abdul Malak, D.
Mediterranean marine protected area (MPA) design patterns regarding geographic distribution, size, spacing and shape were analysed as a proxy of the region's MPA's ecological effectiveness and a first step towards an ecologically coherent MPA network.Results for legally designated MPAs and ecologically functional MPAs accounting for overlaps are presented. Geographically, Mediterranean MPA area is very unevenly distributed, with four-fifths concentrated in just three countries of the north-western part of the basin. Average distance between functional MPAs lies within recommended ecological thresholds, which suggests adequate potential connectivity of the Mediterranean MPA system. Mediterranean designated MPAs are larger than MPAs worldwide on average, although they are generally smaller than international guidance suggests at different levels: ecoregion, country and designation category. On average, Mediterranean designated and functional MPAs have relatively high compactness, which makes them prone to spillover and adequate viability, and less vulnerable to edge effects.
اظهر المزيد [+] اقل [-]Are greenhouse gas emissions from international shipping a type of marine pollution? النص الكامل
2016
Shi, Yubing
Whether greenhouse gas emissions from international shipping are a type of marine pollution is a controversial issue and is currently open to debate. This article examines the current treaty definitions of marine pollution, and applies them to greenhouse gas emissions from ships. Based on the legal analysis of treaty definitions and relevant international and national regulation on this issue, this article asserts that greenhouse gas emissions from international shipping are a type of ‘conditional’ marine pollution.
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