细化搜索
结果 2411-2420 的 6,558
Cartography of littoral rocky-shore communities to assess the ecological status of water bodies through the application of CARLIT method in Algeria (South-Western Mediterranean Sea) 全文
2020
Bahbah, Lamia | Bensari, Bilel | Chabane, Khadidja | Torras, Xavier | Ballesteros, Enric | Seridi, Halima
The cartography of shallow water macroalgal assemblages allows the assessment of water quality in coastal water bodies through the application of CARLIT. In this study, we have applied CARLIT to assess the ecological status of Algerian coastal water bodies for the first time. The surveyed zone is still in a good ecological status since 52% have a good to a high ecological Status. CARLIT index is well correlated with anthropogenic pressures and has proved suitable for the evaluation of the ecological status of coastal waters. Comparison between EQR values and EEI-c shows a similar pattern of change. CARLIT method allowed the collection of accurate information on the distribution and abundance of shallow-water communities. We also provide a cartographic baseline of the coastal assemblages useful for further evaluations on their geographic extension and for the implementation of a monitoring project on water quality in Algerian coast.
显示更多 [+] 显示较少 [-]Management of Enteric Methanogenesis in Ruminants by Algal-Derived Feed Additives 全文
2020
McCauley, Janice I. | Labeeuw, Leen | Jaramillo-Madrid, Ana C. | Nguyen, Luong N. | Nghiem, Long D. | Chaves, Alex V. | Ralph, Peter J.
PURPOSE OF REVIEW: In this paper, we critically review the current state of nutritional management strategies to reduce methane emissions resulting from enteric fermentation in livestock production. In this context, it highlights the novel strategy regarding the use of macroalgal- and microalgal-derived feed additives. RECENT FINDINGS: Several feed management strategies for ruminants focus on the inclusion of nutritional supplements, increasing proportion of starch, or supplementation with high-energy lipids. These strategies aim to improve animal productivity, whilst at the same time reduce methane emissions. Algae supplements are currently investigated as novel ingredients for decreasing methanogenesis, with the potential production of algal biomass also contributing to reducing greenhouse gas emissions. Thus, utilisation of algal biomass as a feed concentrate in dietary supplementation presents a sustainable and environmentally friendly strategy. This review summarises the current stage of research on dietary strategies and their influences on the metabolic processes during enteric fermentation. This information is essential for developing strategies to mitigate methane emissions in the livestock industry. We specifically present the opportunities that algae could offer as a feed additive for methanogenic reduction in cattle. The data compiled from the peer-reviewed literature revealed synergistic effects of algal biomass on methane reduction and animal productivity. However, the challenges regarding the mass cultivation of macro- and microalgae were noticed. Considering the diversity of algal species, future research should increase screening efforts to include more species and dosage evaluation, along with efforts to see if such effects are sustained over time.
显示更多 [+] 显示较少 [-]Trace elements in green turtles (Chelonia mydas) from Rocas Atoll, NE Brazil: Baseline reference from a pristine nesting site 全文
2020
Agostinho, Karoline Fernanda Ferreira | Lacerda, Diego | Tostes, Eloá Corrêa Lessa | Baldassin, Paula | Di Beneditto, Ana Paula Madeira | Carvalho, Carlos Eduardo Veiga de
This study presents the first report on the concentration of trace elements (Al, As, Ba, Cd, Cr, Cu, Fe, Mn, Ni, Pb, V and Zn) in the blood and egg fractions of green turtles from Rocas Atoll, a pristine nesting site in NE Brazil. The highest concentrations of all elements were in the blood or shell samples. In order, iron, Zn, Cu, Al and As presented the highest concentrations in all tissues. The nonessential trace elements were below the limit of detection for more than 50% of the yolk (Al, Cd and Pb) and albumen samples (Al, As, Ba, Cd and Pb). This study will serve as a baseline reference for future monitoring of the ecotoxicology of breeding green turtles in the southwestern Atlantic Ocean.
显示更多 [+] 显示较少 [-]Estimation of tsunami debris on seafloors towards future disaster preparedness: Unveiling spatial varying effects of combined land use and oceanographic factors 全文
2020
Matsuba, Misako | Tanaka, Yusuke | Yamakita, Takehisa | Ishikawa, Yoichi | Fujikura, Katsunori
A large amount of tsunami debris from the Great East Japan Earthquake in 2011 was sunk on the seafloor and threatened the marine ecosystem and local communities' economy, especially in fisheries. However, few studies estimated spatial accumulations of tsunami benthic debris, comparing to their flows on the ocean surface. Here, a spatially varying coefficient model was used to estimate tsunami debris accumulation considering the spatial structure of the data off the Tohoku region. Our model revealed the number of vessels nearest the coast at the tsunami event had the highest positive impact, whereas the distance from the coast and kinetic energy influenced negatively. However, the effect of the proximity to the coast wasn't detected in the Sendai bay, indicating spatial dependency of these effects. Our model estimation provides the fundamental information of tsunami debris accumulation on the seafloor, supporting early reconstruction and risk reduction in marine ecosystems and local communities.
显示更多 [+] 显示较少 [-]Reflecting on an anniversary. The 1970 SS Arrow oil spill in Chedabucto Bay, Nova Scotia, Canada 全文
2020
Lee, Kenneth | Wells, P. G. | Gordon, Donald C.
Fifty years ago, the tanker SS Arrow ran aground in Chedabucto Bay on the east coast of Canada, causing a massive spill of Bunker C oil in winter conditions. This article reflects on this anniversary, briefly describing the spill response and the considerable follow-up research over five decades on the fate and effects of oils spilled in northern cold marine waters. Importantly, the spill led to considerable work in Canada on spill control and bioremediation measures, and advice about oil spills as a marine pollutant of global importance.
显示更多 [+] 显示较少 [-]Dynamic ecological risk modelling of hydrocarbon release scenarios in Arctic waters 全文
2020
Sajid, Zaman | K̲h̲ān, Faiṣal | Veitch, Brian
The Arctic is an ecologically diverse area that is increasingly vulnerable to damages from oil spills associated with commercial vessels traversing newly open shipping lanes. The significance of such accidents on Arctic marine habitats and the potential for recovery can be examined using ecological risk assessment (ERA) coupled with a dynamic object-oriented Bayesian network (DOOBN). A DOOBN approach is useful to represent the probabilistic relationships inherent in the interactions between key events associated with an oil spill, including oil dispersion from the source, ice-oil slick interactions, seawater-oil slick formation, sedimentation, and exposures to different aquatic life. From such analysis, a probabilistic cost analysis can be performed to examine the theoretical cost of habitat services lost and restored. The application of an ERA-DOOBN model to assess oil spills in the Arctic is demonstrated using a case study. The utility of the model output for determining habitat restoration costs and developing policy guidelines for ecological response measures in the Arctic is also discussed.
显示更多 [+] 显示较少 [-]Input of organic matter in Brunei Bay, East Malaysia, as indicated by sedimentary steroids and multivariate statistics 全文
2020
Pang, Swee Yun | Tay, Joo Hui | Suratman, Suhaimi | Simoneit, Bernd R.T. | Mohd Tahir, Norhayati
Brunei Bay is one of the most important marine environments of East Malaysia (South China Sea), covering many productive ecosystems with activities including fisheries, tourism, and main shipping lanes for petroleum transfers. Evaluation of the sources and distributions of steroids in the surface sedimentary organic matter was carried out by gas chromatography–mass spectrometry (GC–MS). The concentrations of the total identified sterols (TIS) ranged between 0.81 and 12.69 μg g⁻¹ dry weight, and the total sterones were between 0.11 and 5.66 μg g⁻¹ dry weight. The coprostanol level was comparatively low (<0.10 μg g⁻¹), and the multi-biomarker proxies indicated that the region did not exhibit significant contamination from sewage effluents. Principal component analysis (PCA) revealed the coastal environment of the study area was dominated by allochthonous (mainly terrestrial) organic matter input.
显示更多 [+] 显示较少 [-]Predominance of Harveyi clade luminous bacteria in coastal waters of South Andaman, India 全文
2020
Chatragadda, Ramesh | Raju, Mohanraju
The diversity, distribution, and mechanisms of bacterial speciation of Vibrio species belonging to Harveyi clade are an important global research interests due to their pathogenic activity in coastal environments. Luminous bacteria are also known to act as environmental indicators in coastal waters. This study demonstrates that luminous bacteria belonging to harveyi clade are predominant in seawater, sediment, surfaces of marine animals and plants, and light organs of leiognathid fishes. Molecular phylogenies for eighteen morphologically distinct and potentially luminous strains chosen out of 57 isolated luminous bacteria. Sequence analysis of luxA gene as a molecular marker identified luminous bacteria belonging to Harveyi clade, Photobacterium clade, and Anguillarum clade distinctly. Rich biodiversity and distribution of luminous bacterial species (30% to 40%) was found in association with coral reef samples of south Andaman. This study confirms and reveals the evidence on predominant association of Harveyi clade luminous vibrio's in coastal waters of south Andaman.
显示更多 [+] 显示较少 [-]Marine debris in Moroccan Mediterranean beaches: An assessment of their abundance, composition and sources 全文
2020
Mghili, Bilal | Analla, Mohamed | Aksissou, Mustapha | Aissa, Chaimae
Morocco is well known for its attractive Mediterranean beaches, which play an important economic role. With the fast development and growth, these beaches have become more contaminated by marine debris. This paper examined the abundance, composition and marine debris sources on five beaches in the Moroccan Mediterranean during 2019 four seasons. A total of 7839 marine debris were collected from the five beaches with a total weight of 231 kg. The average density of the debris collected was 0.20 ± 0.098 items/m². Polymer materials constituted the majority of debris found, with a percentage of 71.36%, followed by paper/cardboard (11.50%), metal (5.77%), processed wood (5.34%), cloth/textile (2.51%) and glass/ceramics (1.76%). Human recreational activities were the main source of debris (70.13%), followed by smoking-related (13.98%). Debris density appears to be particularly influenced by beach users. Awareness campaigns are needed for beach users to improve the quality of the beaches.
显示更多 [+] 显示较少 [-]Microplastics in subsurface coastal waters along the southern coast of Viti Levu in Fiji, South Pacific 全文
2020
Dehm, Jasha | Singh, Shubha | Ferreira, Marta | Piovano, Susanna
Microplastics in subsurface coastal waters along the southern coast of Viti Levu in Fiji, South Pacific 全文
2020
Dehm, Jasha | Singh, Shubha | Ferreira, Marta | Piovano, Susanna
Microplastics (MPs) remain largely understudied in Small Island Developing States. This study is aimed at comparing the abundance and characteristics of MPs in rural and urban marine coastal sites located along the southern coast of Fiji's main inhabited island, Viti Levu. Collection of subsurface waters (at depth of ca. 0.6 m) was performed at seven sites via Niskin bottle. Samples were filtered over a membrane filter to extract MPs and to allow visual analysis and polymer identification by using attenuated total reflectance in Fourier transform infrared spectroscopy. Findings from this study depict widespread presence of MPs in both urban and rural sites, and show no significant differences in the four parameters studied, i.e. abundance of MP pieces (2.0 vs 1.6 MP/L, respectively), form types (dominance of fibers), size (0.5–0.9 and 1.0–1.4 mm totaling 48% of the samples), and color (blue contributing 30%, and red and black contributing 25% each). These findings challenge the common expectation of a higher MPs pollution in urban areas compared to rural areas.
显示更多 [+] 显示较少 [-]Microplastics in subsurface coastal waters along the southern coast of Viti Levu in Fiji, South Pacific 全文
2020
Dehm, Jasha | Singh, Shubha S. | Ferreira, Marta | Piovano, Susanna
Microplastics (MPs) remain largely understudied in Small Island Developing States. This study is aimed at comparing the abundance and characteristics of MPs in rural and urban marine coastal sites located along the southern coast of Fiji's main inhabited island, Viti Levu. Collection of subsurface waters (at depth of ca. 0.6 m) was performed at seven sites via Niskin bottle. Samples were filtered over a membrane filter to extract MPs and to allow visual analysis and polymer identification by using attenuated total reflectance in Fourier transform infrared spectroscopy. Findings from this study depict widespread presence of MPs in both urban and rural sites, and show no significant differences in the four parameters studied, i.e. abundance of MP pieces (2.0 vs 1.6 MP/L, respectively), form types (dominance of fibers), size (0.5�0.9 and 1.0
显示更多 [+] 显示较少 [-]