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Resultados 2541-2550 de 6,535
Trajectory of coastal wetland vegetation in Xiangshan Bay, China, from image time series
2020
Liu, Yongchao | Liu, Yongxue | Li, Jialin | Sun, Chao | Xu, Wenxuan | Zhao, Bingxue
Coastal wetland vegetation is crucial for providing multiple ecosystem services. However, accurate assessment of wetland vegetation is problematic due to the challenging coastal environment. Using Xiangshan Bay (XB) in China as a typical case study, we developed a time series biological phenological approach to classifying coastal wetland vegetation using Landsat time-series images from 1984 to 2018. The results demonstrate that the total vegetation area of coastal wetlands in XB in 2018 was ~85.3 km². The interannual dynamics of coastal wetland vegetation area in XB in the last 35 years can be divided into three periods: increasing volatility (1984–1998), decreasing (1999–2004), and increasing volatility (2005–2018). Our results emphasize the potential of the use of the time-series biological phenological approach for monitoring coastal wetland vegetation, which can contribute to the sustainable management of coastal ecosystems.
Mostrar más [+] Menos [-]Investigation of the toxic effects of different polystyrene micro-and nanoplastics on microalgae Chlorella vulgaris by analysis of cell viability, pigment content, oxidative stress and ultrastructural changes
2020
Hazeem, Layla J. | Yesilay, Gamze | Bououdina, Mohamed | Perna, Simone | Cetin, Demet | Suludere, Zekiye | Barras, Alexandre | Boukherroub, Rabah
Plastics of different sizes (micro- and nano-sized) are often identified in aquatic environments. Nevertheless, their influence on marine organisms has not been widely investigated. In this study, the responses of the microalga Chlorella vulgaris to micro- and nanoplastics exposure were examined using long term toxicity test. The plastics tested were carboxyl-functionalized and non-functionalized polystyrene of 20, 50 and 500 nm in diameter. A reduction in algal cell viability and chlorophyll a concentration has been observed after exposure to the small sizes (20 and 50 nm) of plastics. Lactate dehydrogenase activity and reactive oxygen species concentration/production were significantly higher after exposure to the 20 nm nanoplastics than that of control confirming the stress condition. Fourier transform infrared (FTIR) spectroscopy analysis proved the attachment of nanoplastics to microalgae and rearrangement of extracellular polymeric substances. The cellular stress appeared as increased cell size, deformed cell wall and increased volume of starch grains.
Mostrar más [+] Menos [-]δ15N in deployed macroalgae as a tool to monitor nutrient input driven by tourism activities in Mediterranean islands
2020
Signa, Geraldina | Andolina, Cristina | Tomasello, Agostino | Mazzola, Antonio | Vizzini, Salvatrice
Mediterranean Sea is among the world's leading tourist destinations; however, the sharp increase in tourists during the high season may affect coastal seawater. The main aim of this study was to evaluate the occurrence and temporal variation of anthropogenic nutrients in coastal seawater in relation to tourist flows in three Mediterranean islands (Cyprus, Sicily and Rhodes), through short-term macroalgae deployments, coupled with δ¹⁵N analysis and GIS mapping. In all islands, an overall increase in macroalgae δ¹⁵N occurred over the deployment carried out in August in the tourist sites, suggesting the presence of anthropogenic nutrients. Decreasing δ¹⁵N values occurred at increasing distance from the coastline in two out of the three islands (Cyprus and Sicily). This study revealed the usefulness of the approach used in the assessment of tourism impact in terms of trophic enrichment and its potential to support competent authorities for the development of sustainable coastal management plans.
Mostrar más [+] Menos [-]Determination and comparison of anionic surfactant and phosphate concentrations at the entrance and the exit of the Turkish Straits System (TSS)
2020
Balcıoğlu, Esra Billur
A comparison study was performed on anionic surfactant and phosphate concentrations between the entrance and the exit of Turkish Straits System (TSS). Surface water samples were collected at fall season in 2016 and the spring season in 2017. According to the values obtained from the samples taken from 6 stations at the entrance and 7 at the exit, anionic surfactant values were high at the exit of the TSS, while the phosphate concentrations were relatively lower. The high phosphate values at the entrance are related to the eutrophic feature of the Black Sea. Also, the location of these stations covers one end of the Canal Istanbul Project, which is planned to be built soon, so the data of this study will constitute an important database.
Mostrar más [+] Menos [-]Catching the variety: Obtaining the distribution of terminal velocities of microplastics particles in a stagnant fluid by a stochastic simulation
2020
Isachenko, Igor
A simple stochastic numerical model is applied to obtain the distribution of the terminal settling/rising velocity of a set of MPs particles whose size, shape, and density have their distributions in accordance with field observations and production trends. Results of the direct Monte Carlo simulation are shown to reproduce well the data of laboratory experiments. Distributions of MPs by size and density appear to be more valuable for the final terminal velocity distribution compared to the influence of the distribution by shape. The most “real” of the simulated distributions of the terminal velocity of MPs particles in the ocean has a multimodal shape, slightly different for fresh and saline waters. Multimodality arises from the fact that the terminal velocity depends on several physical parameters simultaneously and thus should be an expected feature of MPs terminal velocity distribution.
Mostrar más [+] Menos [-]Activity-footprints, pressures-footprints and effects-footprints – Walking the pathway to determining and managing human impacts in the sea
2020
Elliott, Michael | Borja, Angel | Cormier, Roland
Determining the overall effects of human activities on the estuaries, seas and coasts, as a precursor to marine management, requires quantifying three aspects. These are: (a) the area in which the human activities take place, (b) the area covered by the pressures generated by the activities on the prevailing habitats and species, in which pressures are defined as the mechanisms of change, and (c) the area over which any adverse effects occur. These features can be respectively termed the activities-footprints, the pressures-footprints and the effects-footprints. The latter in turn incorporates both the effects on the natural system and the effects on ecosystem services from which society extracts goods and benefits. This viewpoint article explains the rationale behind this typology and proposes definitions for each of these three types of footprints.
Mostrar más [+] Menos [-]European eels and heavy metals from the Mar Menor lagoon (SE Spain)
2020
Romero, Diego | Barcala, Elena | María-Dolores, Emilio | Muñoz, Pilar
Heavy metal pollution is related to the fall in European eel (Anguilla anguilla) populations. The Mar Menor lagoon (SE Spain) is home to an endangered population of this species, which is still caught for human consumption. The presence of Pb, Cd and Hg in the livers and muscles and the Se:Hg ratio in muscle of 150 eels from this lagoon were determined. Pb concentrations were higher than those reported from other populations in the world, while Cd and Hg concentrations in the tissues analysed were lower. In terms of food safety, Se concentrations play an important role in sequestering Hg in eels from this lagoon.
Mostrar más [+] Menos [-]Recognizing peripheral ecosystems in marine protected areas : A case study of golden jellyfish lakes in Raja Ampat, Indonesia
2020
Maas, Diede L. | Capriati, Agustin | Ahmad, Awaludinnoer | Erdmann, Mark V. | Lamers, Machiel | de Leeuw, Christiaan A. | Prins, Luca | Putri, Amanda P. | Tapilatu, Ricardo F. | Becking, Leontine E.
Peripheral marine ecosystems can harbor endemic diversity and attract tourism attention, yet are generally not included in conservation management plans due to their remoteness or inland positioning. A case study in Raja Ampat of seven landlocked marine lakes containing golden jellyfish (Mastigias spp.) was conducted to address the lack of fundamental insights into evolutionary, ecological and social contexts of these ecosystems. An interdisciplinary approach was taken towards identifying the jellyfish lakes as distinct management units in order to incorporate them into existing Marine Protected Areas. Mastigias papua populations showed strong genetic (ϕST: 0.30–0.86) and morphological (F = 28.62, p-value = 0.001) structure among lakes, with putative new subspecies. Risks arising from rapid increase in tourism to Raja Ampat (30-fold since 2007) warrant restrictions on jellyfish lake use. Recommendations are provided for adaptive management and science-based conservation policies for jellyfish lakes across Indonesia.
Mostrar más [+] Menos [-]Polycyclic Aromatic Hydrocarbons: Sources, Occurrence, Levels, Distribution and Ecotoxicological Fate at Coastal and Deep Ocean
2020
Oliva, Ana Laura | Ronda, Ana Carolina | Girones, Lautaro | Orazi, Melina Mirta | Recabarren Villalón, Tatiana Valentina | Marcovecchio, Jorge Eduardo | Arias, Andres Hugo | Arias, Andres Hugo | Botté, Sandra Elizabeth
This chapter presents general aspects of polycyclic aromatic hydrocarbons (PAHs) as environmental pollutants and synthesizes information on the presence and levels of PAHs in the coasts and deep sea throughout the world. PAHs are a large group of compounds formed of two or more fused benzene rings or, in some cases, a pentagonal ring. PAHs are solid at room temperature and characterized by low steam pressures and low water solubility, as well as high melting and boiling points. PAHs can originate from three possible sources: petrogenic, pyrolytic and natural. Although PAHs can occur naturally, anthropogenic activities are generally considered the major source of PAHs released into the environment. PAHs can be introduced into marine environments by different ways: spillage of fossil fuels, ship traffic, atmospheric depositions, urban runoff, and municipal and industrial wastewater discharge. PAHs associated with sediments are considered to be less bioavailable to organisms and therefore less toxic for aquatic biota than PAHs dissolved in seawater. | Fil: Oliva, Ana Laura. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto Argentino de Oceanografía. Universidad Nacional del Sur. Instituto Argentino de Oceanografía; Argentina | Fil: Ronda, Ana Carolina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto Argentino de Oceanografía. Universidad Nacional del Sur. Instituto Argentino de Oceanografía; Argentina. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia; Argentina | Fil: Girones, Lautaro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto Argentino de Oceanografía. Universidad Nacional del Sur. Instituto Argentino de Oceanografía; Argentina | Fil: Orazi, Melina Mirta. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto Argentino de Oceanografía. Universidad Nacional del Sur. Instituto Argentino de Oceanografía; Argentina | Fil: Recabarren Villalón, Tatiana Valentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto Argentino de Oceanografía. Universidad Nacional del Sur. Instituto Argentino de Oceanografía; Argentina | Fil: Marcovecchio, Jorge Eduardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto Argentino de Oceanografía. Universidad Nacional del Sur. Instituto Argentino de Oceanografía; Argentina. Universidad FASTA "Santo Tomas de Aquino"; Argentina. Universidad Tecnológica Nacional. Facultad Regional Bahía Blanca; Argentina. Academia Nacional de Ciencias Exactas, Físicas y Naturales; Argentina | Fil: Arias, Andres Hugo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto Argentino de Oceanografía. Universidad Nacional del Sur. Instituto Argentino de Oceanografía; Argentina. Universidad Nacional del Sur. Departamento de Química; Argentina
Mostrar más [+] Menos [-]Zn/Pb concentration ratios emphasize spatiotemporal airborne metal dynamics in soils under different land use.
2020
van Oort, Folkert | Monna, Fabrice | Garnier, Stéphane | Ecologie fonctionnelle et écotoxicologie des agroécosystèmes (ECOSYS) ; AgroParisTech-Université Paris-Saclay-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE) | Archéologie, Terre, Histoire, Sociétés [Dijon] (ARTeHiS) ; Ministère de la Culture et de la Communication (MCC)-Université de Bourgogne (UB)-Centre National de la Recherche Scientifique (CNRS) | Biogéosciences [UMR 6282] (BGS) ; Université de Bourgogne (UB)-Centre National de la Recherche Scientifique (CNRS) | French Ministry of Environment (MATE-SRAE-95.245) ; CNRS ToxNuc-E program (2003-2006).
International audience | Zinc (Zn) and lead (Pb) concentrations were measured in 173 samples collected in soils under forest, wetland, and arable land around a Zn smelter plant that stopped activity in the 1960s. The adopted sampling strategy consisted in collecting 0–30-cm-depth samples from all soils, tilled or not, in order to harmonize the analyzed soil volume to that of plowed soils. Airborne deposition was modeled as a function of the distance from the pollution source and of land use. The Zn/Pb concentration ratios in the surface layer remarkably contrasted 3–4, 1.5–2, and ~ 0.5 for arable, wetland, and forest soils, respectively, independently from the distance to the emission source, while total Zn and Pb concentrations, taken separately, were only slightly discriminant. For metal pollution sites originating from former industrial activity, Zn/Pb concentration ratios determined on relevant soil samples represent a powerful indicator that provides easy and rapid information in real field conditions on time-related input/output dynamics of mobile and less-mobile metal pollutants, and hence, on interactions between pollutants and soils under different land use conditions.
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