Refinar búsqueda
Resultados 2371-2380 de 6,558
Sorption of okadaic acid lipophilic toxin onto plastics in seawater Texto completo
2020
Costa, Sara T. | Rudnitskaya, Alisa | Vale, Carlos | Guilhermino, Lúcia | Botelho, Maria João
The present study tested under laboratorial conditions the sorption of okadaic acid (OA), a lipophilic toxin produced by marine phytoplankton, onto 6-mm plastic circular fragments. Fragments (4 g L⁻¹) of polyethylene terephthalate (PET), polypropylene (PP), expanded polystyrene (EPS) and non-expanded polystyrene (PS) were exposed for 96 h to seawater spiked with 10 ng mL⁻¹ of OA. Results of the experiments showed a broad percentage of OA removed from the water by plastics after 48 h of exposure: 30 ± 5.1% (PET), 37 ± 9.5% (PP), 62 ± 7.1% (EPS) and 83 ± 1.9% (PS). Sorption appears to be highly influenced by polymer's characteristics, such as polarity and degree of crystallinity. Further studies are needed to clarify the effect of the contact area on sorption by expanded plastics. These results point to the plausible interaction of OA and plastics in coastal waters.
Mostrar más [+] Menos [-]Performance trends of environmental management in European ports Texto completo
2020
Puig, Martí | Raptis, Sotiris | Wooldridge, Chris | Darbra, R.M.
This paper presents the current status and trends over time in the environmental situation of European ports, based on the results of a wide representation of EcoPorts members (90 ports). All the information presented in this research comes from the Self-Diagnosis Method (SDM), a concise checklist managed by European Sea Ports Organisation (ESPO), against which ports can self-assess their environmental management. The results provide data on a total number of 54 indicators, being the existence of an inventory of environmental legislation the indicator with the highest implementation (96,7%), followed by the existence of an environmental policy (95,7%). Waste is the environmental issue that is being more monitored by ports. Air quality continues as the top environmental priority, followed by energy consumption and noise. It is interesting to highlight the growing awareness of Climate change among ports as well as the increasing implementation of green initiatives in ports.
Mostrar más [+] Menos [-]Mapping marine litter with Unmanned Aerial Systems: A showcase comparison among manual image screening and machine learning techniques Texto completo
2020
Gonçalves, Gil | Andriolo, Umberto | Pinto, Luis | Duarte, Diogo
Recent works have shown the feasibility of Unmanned Aerial Systems (UAS) for monitoring marine pollution.We provide a comparison among techniques to detect and map marine litter objects on an UAS-derived orthophoto of a sandy beach-dune system. Manual image screening technique allowed a detailed description of marine litter categories. Random forest classifier returned the best-automated detection rate (F-score 70%), while convolutional neural network performed slightly worse (F-score 60%) due to a higher number of false positive detections.We show that automatic methods allow faster and more frequent surveys, while still providing a reliable density map of the marine litter load. Image manual screening should be preferred when the characterization of marine litter type and material is required.Our analysis suggests that the use of UAS-derived orthophoto is appropriate to obtain a detailed geolocation of marine litter items, requires much less human effort and allows a wider area coverage.
Mostrar más [+] Menos [-]Worldwide contamination of fish with microplastics: A brief global overview Texto completo
2020
Sequeira, Inês F. | Prata, Joana C. | da Costa, João P. | Duarte, Armando C. | Rocha-Santos, Teresa
Widespread contamination of microplastics may lead to internalization in fish. This literature review from March 2019 to March 2020 details that a median of 60% of fish, belonging to 198 species captured in 24 countries, contain microplastics in their organs. Carnivores species ingested more microplastics than omnivores. Only 14% of fish were from aquaculture. Most studies focused on digestive systems, with presence in other organs currently being insufficiently assessed. Based on this assessment, knowledge gaps that should be addressed in future studies were identified.
Mostrar más [+] Menos [-]Α systematic meta-review analysis of review papers in the marine plastic pollution literature Texto completo
2020
Aretoulaki, Eleni | Ponis, Stavros | Plakas, George | Agalianos, Konstantinos
The omnipresence of plastic particles in marine ecosystems, a.k.a. Marine Plastic Pollution (MPP) constitutes a major environmental and socioeconomic threat. In the last decade, the realization of the severity of the MPP problem by international organizations, governments and policy makers worldwide, has triggered the publication of a large number of review papers studying the current state of the art of MPP, from a plethora of different perspectives. This study attempts to classify the existing review efforts, by conducting a systematic analysis of review papers on MPP, published from 2000 to 2019. A sample of 114 review studies, retrieved from the SCOPUS database, are classified based on a number of carefully selected coding criteria and processed in order to produce a set of meaningful descriptive statistics and visualizations. Ultimately, the objective of this paper is to synthesize the different perspectives on MPP, assess the research progress and highlight future research directions.
Mostrar más [+] Menos [-]Anthropogenic debris in the digestive tract of a southern right whale (Eubalaena australis) stranded in Golfo Nuevo, Argentina Texto completo
2020
Alzugaray, L. | Di Martino, M. | Beltramino, L. | Rowntree, V.J. | Sironi, M. | Uhart, M.M.
Over the past fifty years, interactions between anthropogenic debris and a wide range of marine species have increased. In cetaceans, the most frequent interactions have occurred through ingestion and/or entanglement, with results ranging from minor injuries to death in affected animals. While debris ingestion is widely documented in odontocetes, records are scarcer in mysticetes. This study describes the finding of plastic litter in the digestive tract of a southern right whale (Eubalaena australis) juvenile male, which was found dead on the shores of Golfo Nuevo, Chubut, Argentina in 2014. During the examination of intestinal contents, anthropogenic waste was found and classified as macro-debris (25 mm-1 m). Although this whale likely died of causes not related to this finding, it is the first record of anthropogenic debris ingestion for this species. This event adds information about the potential impact of human-made debris on a variety of aquatic species and ecosystems.
Mostrar más [+] Menos [-]Prevalence of entanglements of seabirds in marine debris in the central Portuguese coast Texto completo
2020
Costa, R.A. | Sá, S. | Pereira, A.T. | Ângelo, A.R. | Vaqueiro, J. | Ferreira, M. | Eira, C.
Plastic pollution and the subsequent entanglement of marine animals is a global and increasing problem. In this study we present an analysis of the seabirds recorded as entangled by a rehabilitation centre and an associated marine animal stranding network, along the central coast of Portugal, between 2008 and 2018. Results show a high annual rate of entangled seabirds (average 6.9%) compared to other studies and fisheries related materials are a relevant cause of seabird entanglement (82%) compared to other debris. When comparing age classes, juveniles were more vulnerable to entanglement than other age classes in the species studied. Regarding the rehabilitation of entangled seabirds, the release rate was higher in non-fishing material entanglement cases. In conclusion, this study highlights the impact of fisheries related material on marine fauna and the need for reinforcement of the existing legislation for protecting seabirds and the implementation of mitigation measures associated with fishing activities.
Mostrar más [+] Menos [-]Long-term variations of phytoplankton community in relations to environmental factors in Deep Bay, China, from 1994 to 2016 Texto completo
2020
Wang, Rui | Liu, Xiaowan | Wu, Jiajun | Wai, Tak-Cheung | Shen, Pingping | Lam, Paul K.S.
Long-term effects of environmental factors on phytoplankton community in Deep Bay, Hong Kong, were investigated from 1994 to 2016. Phytoplankton community experienced three important shifts: small flagellates and Chroomonas spp. dominated from 1994 to 2006. Heavy blooms of diatoms Skeletonema costatum and Thalassiosira spp. occurred and became the dominant species between 2007 and 2009. Phytoplankton community was dominated by small flagellates and Chroomonas spp. from 2010 to 2015, and their abundance was much higher than earlier periods. Abundance of Chroomonas spp. decreased sharply in 2016, and Thalassiosira spp. became the dominant species. Phytoplankton community changed from consisting mainly of small flagellates and Chroomonas spp. to more diatoms, changing from ~90% to ~45% for other species abundance and from <10% to ~55% for diatoms. Nitrite, 5-day biochemical oxygen demand, salinity, suspended solids and turbidity were more influential on phytoplankton variation (23.65% explained by all the variables).
Mostrar más [+] Menos [-]Allelopathic inhibitory effect of the macroalga Pyropia haitanensis (Rhodophyta) on harmful bloom-forming Pseudo-nitzschia species Texto completo
2020
Patil, Vishal | Abate, Rediat | Wu, Weiwei | Zhang, Jiawei | Lin, Huina | Chen, Changping | Liang, Junrong | Sun, Lin | Li, Xuesong | Li, Yang | Gao, Yahui
The blooms of harmful microalgae represent a prominent threat to fisheries, public health, and economies throughout the world. Recent studies have shown that certain macroalgae release allelochemicals that can inhibit the growth of bloom-forming microalgae. In this study, we found that the macroalga Pyropia haitanensis significantly inhibited growth of the harmful bloom-forming microalgae Pseudo-nitzschia pungens and Pseudo-nitzschia multiseries. The inhibitory-effect of the live thali of P. haitanensis was highest, followed by that of dry powder, water-soluble extract, and culture medium filtrate. The Pseudo-nitzschia species died 96 h after exposure to 5–10 g fresh-weight L⁻¹ of P. haitanensis live thalli. Furthermore, an aqueous extract of P. haitanensis suppressed the growth of P. pungens and P. multiseries, thereby indicating that P. haitanensis contains stable allelopathic substances that cause the observed inhibitory-effects. On the basis of these findings, we conclude that the macroalga P. haitanensis would have potential utility in controlling the blooms of Pseudo-nitzschia species.
Mostrar más [+] Menos [-]Changes in Cd and Zn distribution in sediments after closure of an electroplating industry, Sepetiba bay, Brazil Texto completo
2020
Rodrigues, Sarah K. | Machado, Wilson | Guerra, Josefa V. | Geraldes, Mauro | Morales, Shéron | Vinzón, Susana B.
The spatiotemporal attenuation of Cd and Zn concentrations was assessed in sediments from Sepetiba Bay, which is a coastal system that has been historically impacted by industrial wastes. The evolution of contamination over the years shortly before and after cessation of electroplating industry activities, by the end of 1990's, was elucidated by reviewing the existing datasets for the whole bay area. Metal concentrations exceed Brazilian Sediment Quality Guidelines in most regions, corresponding to concentrations 3 to 4 orders of magnitude higher than background levels and Enrichment Factors reaching values significantly higher than 40 for both elements. In the second decade after electroplating industry closure, the levels of Cd and Zn lowered in most regions of the bay. However, an increase in the relative importance of diffuse sources can mislead the current and future identification of Cd and Zn input, bringing new challenges for environmental monitoring and management for Sepetiba bay.
Mostrar más [+] Menos [-]