خيارات البحث
النتائج 1631 - 1640 من 4,937
Whale carcass leachate plumes in beach groundwater: A potential shark attractant to the surf? النص الكامل
2019
Tucker, James P. | Santos, Isaac R. | Davis, Kay L. | Butcher, Paul A.
With the recovery of whale populations, carcass strandings on beaches are growing. Beach burial is a common management option for stranded carcasses. However, communities fear shark attraction following leachate transport to the ocean via submarine groundwater discharge. Here, a sediment column mesocosm experiment indicated that carcasses can be a localised source of dissolved organic carbon (DOC), phosphate and ammonium to groundwater. The spatial reach of the leachate plume was <2.5 m, while the temporal stabilisation occurred over 100–300 days. No significant chemical signals were observed under a beach-buried carcass, implying effective attenuation of decomposition plumes. For beaches with conditions similar to our one-directional, fast-flowing sediment experiment generating extreme groundwater contamination, it is unlikely that any leachate from a whale carcass would reach the ocean if buried >25 m onshore. Therefore, carcass leachate plumes would only potentially attract sharks to the surf under specific conditions not experienced during our experiments.
اظهر المزيد [+] اقل [-]A novel GIS-based tool for predicting coastal litter accumulation and optimising coastal cleanup actions النص الكامل
2019
Haarr, Marthe Larsen | Westerveld, Levi | Fabres, Joan | Iversen, Kriss Rokkan | Busch, Kjersti Eline Tønnessen
Effective site selection is a key component of maximising debris removal during coastal cleanup actions. We tested a GIS-based predictive model to identify marine litter hotspots in Lofoten, Norway based on shoreline gradient and shape. Litter density was recorded at 27 randomly selected locations with 5 transects sampled in each. Shoreline gradient was a limiting factor to litter accumulation when >35%. The curvature of the coastline correlated differently with litter density at different spatial scales. The greatest litter concentrations were in small coves located on larger headlands. A parsimonious model scoring sites on a scale of 1–5 based on shoreline slope and shape had the highest validation success. Sites unlikely to have high litter concentrations were successfully identified and could be avoided. The accuracy of hotspot identifications was more variable, and presumably more parameters influencing litter deposition, such as shoreline aspect relative to prevailing winds, should be incorporated.
اظهر المزيد [+] اقل [-]Ecological health assessment of a coastal ecosystem: Case study of the largest brackish water lagoon of Asia النص الكامل
2019
Barik, Saroja Kumar | Bramha, Satyanarayan | Behera, Dibakar | Bastia, Tapan Kumar | Cooper, Gregory | Rath, Prasanta
This study focuses on the ecological health assessment of Chilika, a shallow lagoon present in east coast of India, through nutrient stoichiometry and trophic state index (TSI). Multivariate statistical analysis such as ANOVA, Pearson's correlation, Principal Component Analysis (PCA), and Discriminant Analysis (DA) were employed for data interpretation. Nutrient stoichiometry revealed that the Chilika Lagoon experiences phosphorus limitation with regard to nitrogen and silicate (N:P:Si = 16:1:16) throughout the study period. As per the computed TSI values, the southern sector (SS), central sector (CS), and outer channel (OC) were assigned with a mesotrophic status, whereas the northern sector (NS) was assigned with the eutrophic status. From PCA, total nitrogen was found to be negatively correlated with salinity and positively correlated with silicate, thus indicating that the major source of nitrogen in the lagoon was freshwater ingress by rivers with high silicate content. DA indicated that it was successful in discriminating the groups as predicted.
اظهر المزيد [+] اقل [-]Physiological impacts of pollution exposure in seabird's progeny nesting in a Mediterranean contaminated area النص الكامل
2019
Oudi, Abir | Chokri, Mohamed Ali | Hammouda, Abdessalem | Chaabane, Rim | Badraoui, Riadh | Besnard, Aurélien | Santos, Raphaël
Physiological impacts of pollution exposure in seabird's progeny nesting in a Mediterranean contaminated area النص الكامل
2019
Oudi, Abir | Chokri, Mohamed Ali | Hammouda, Abdessalem | Chaabane, Rim | Badraoui, Riadh | Besnard, Aurélien | Santos, Raphaël
Aquatic wildlife is exposed through trophic transfer of hazardous substances to several threats inducing physiological impairments. We aimed at assessing the impact of contamination in one of the hot spots of pollution along Mediterranean coasts, the gulf of Gabes in Tunisia, on Common tern Sterna hirundo, a piscivorous top predator bird. Firstly, we compared the reproductive effort of breeding adults through clutch size distribution in three sites with different levels of pollution. Then, a battery of genotoxicity and oxidative stress biomarkers was carried out to assess physiological impairments in chicks. While defense mechanisms showed a depletion, lipid peroxidation and genotoxicity increased significantly according to pollution level. The multi-biomarker approach used here, discriminated chicks according to contamination degree of their nesting sites. Increases in genotoxicity and oxidative stress were correlated to a decrease in chick body mass known to lead to long-term impacts on juvenile survival and recruitment in birds.
اظهر المزيد [+] اقل [-]Physiological impacts of pollution exposure in seabird's progeny nesting in a Mediterranean contaminated area النص الكامل
2019
Oudi, Abir | Chokri, Mohamed Ali | Hammouda, Abdessalem | Chaabane, Rim | Badraoui, Riadh | Besnard, Aurélien | Santos, Raphael | Université de Gabès = University of Gabes | Hedi Chaker Hospital [Sfax] (CHU Sfax) | جامعة صفاقس - Université de Sfax - University of Sfax | Centre d’Ecologie Fonctionnelle et Evolutive (CEFE) ; Université Paul-Valéry - Montpellier 3 (UPVM)-Institut National de la Recherche Agronomique (INRA)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro)-École Pratique des Hautes Études (EPHE) ; Université Paris Sciences et Lettres (PSL)-Université Paris Sciences et Lettres (PSL)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [Occitanie])-Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro) | Haute École spécialisée de Suisse occidentale = HES-SO University of Applied Sciences and Arts Western Switzerland = Fachhochschule Westschweiz [Schweiz] (HES-SO)
International audience | Aquatic wildlife is exposed through trophic transfer of hazardous substances to several threats inducing physiological impairments. We aimed at assessing the impact of contamination in one of the hot spots of pollution along Mediterranean coasts, the gulf of Gabes in Tunisia, on Common tern Sterna hirundo, a piscivorous top predator bird. Firstly, we compared the reproductive effort of breeding adults through clutch size distribution in three sites with different levels of pollution. Then, a battery of genotoxicity and oxidative stress biomarkers was carried out to assess physiological impairments in chicks. While defense mechanisms showed a depletion, lipid peroxidation and genotoxicity increased significantly according to pollution level. The multi-biomarker approach used here, discriminated chicks according to contamination degree of their nesting sites. Increases in genotoxicity and oxidative stress were correlated to a decrease in chick body mass known to lead to long-term impacts on juvenile survival and recruitment in birds.
اظهر المزيد [+] اقل [-]Metagenomic analysis of tarball-associated bacteria from Goa, India النص الكامل
2019
Fernandes, Clafy | Kankonkar, Harshada | Meena, Ram Murti | Menezes, Gilda | Shenoy, Belle Damodara | Khandeparker, Rakhee
The beaches of Goa state in India are frequently polluted with tarballs, specifically during pre-monsoon and monsoon seasons. Tarballs contain hydrocarbons, including polycyclic aromatic hydrocarbons, which pose significant environmental risks. Microbes associated with tarballs reportedly possess capabilities to degrade toxic hydrocarbons present in tarballs. In this study, bacterial diversity associated with tarballs from Vagator and Morjim beaches of north Goa was analysed based on V3–V4 regions of 16S rRNA gene sequenced using Illumina Miseq Platform. The Proteobacterial members were dominant in both Vagator (≥85.5%) and Morjim (≥94.0%) samples. Many of the identified taxa have been previously reported as hydrocarbon degraders (e.g. Halomonas, Marinobacter) or possible human pathogens (e.g. Acinetobacter, Klebsiella, Rhodococcus, Staphylococcus, Vibrio). This is the first study reported on a metagenomic analysis of bacteria associated with tarballs from Goa.
اظهر المزيد [+] اقل [-]Status and recent trends in coral reefs of the Philippines النص الكامل
2019
Licuanan, W.Y. | Robles, R. | Reyes, M.
Concern about the condition of Philippine coral reefs has prompted a recent reassessment of the status of the nation's reefs, the results of which are reported here. This paper presents the largest updated dataset on Philippine coral cover and generic diversity. The dataset was obtained from equally-sized sampling stations on fore-reef slopes of fringing reefs in six biogeographic regions using identical methods. A total of 206 stations were surveyed from 2014 to 2017, and another 101 stations were monitored from 2015 to 2018.The weighted average hard coral cover (HCC) was 22.8% (±1.2 SE) and coral generic diversity averaged 14.5 (±0.5 SE). Both were highest in the fully-formed reefs of the Sulu Sea biogeographic region and lowest in the eastern Philippines. Comparisons of findings with those of previous assessments show the continued decline in coral cover over a larger time scale, with the loss of about a third of the reef corals over the last decade. However, no consistent changes were evident in the 101 monitoring stations from 2015 to 2018 despite the global coral bleaching event. An expanded monitoring program, not just one-off assessments, is recommended to improve reef management in the Philippines.
اظهر المزيد [+] اقل [-]Bioavailability of dissolved organic nitrogen and its uptake by Ulva prolifera: Implications in the outbreak of a green bloom off the coast of Qingdao, China النص الكامل
2019
Xiu, Bin | Liang, Sheng-kang | He, Xing-liang | Wang, Xin-ke | Cui, Zheng-guo | Jiang, Zhi-jian
To investigate bioavailability of dissolved organic nitrogen (DON) and its contribution to nitrogen demand for Ulva prolifera, a cruise was conducted during a bloom of U. prolifera in Qingdao coastal waters, China, dissolved inorganic nitrogen (DIN) and DON components were investigated. Uptakes of both DIN and DON by U. prolifera were synchronously measured onboard using stable isotope techniques. The contribution of DON to total dissolved N (TDN) was >50% and that of labile components (urea and to amino acids, AA) to DON exceeded 30%. Both DIN and DON were utilized by U. prolifera, which uptake NH4-N preferentially, then urea, NO3-N and AA in turn; whereas the ranking of turnover times from short to long was AA, NH4-N, urea and NO3-N. The high uptake rates and short turnover time of AA and urea indicated that DON may play an important role in the nutrition of U. prolifera.
اظهر المزيد [+] اقل [-]Dynamic of small polyethylene microplastics (≤10 μm) in mussel's tissues النص الكامل
2019
Fernández, Beatriz | Albentosa, Marina
Dynamic of small polyethylene microplastics (≤10 μm) in mussel's tissues النص الكامل
2019
Fernández, Beatriz | Albentosa, Marina
MPs' uptake and tissue accumulation were investigated in mussel exposed to a single dose (2.85 mg ind⁻¹, 3 mg l⁻¹) of a heterogeneous mixture of irregularly shaped particles of HDPE (mainly ≤10 μm), followed by a 7 days depuration period. The results showed that mussels efficiently cleared MPs from water during exposure, and that MPs were accumulated in digestive gland and gills during depuration. In digestive gland, the amount and size of the MPs accumulated decreased with time, indicating a slower processing and elimination of small MPs than of larger ones. In gills, MPs' burdens increased with time, the MPs accumulated were the smallest ones, suggesting the translocation of small MPs from the digestive system to the gills. The hazardous potential of the smaller fraction of MPs (≤4 μm) underlined that more focus should be directed towards the accumulation and effects of this fraction of MPs in the marine environment.
اظهر المزيد [+] اقل [-]Dynamic of small polyethylene microplastics (<10 um) in mussel´s tissues النص الكامل
2019
Fernández-Galindo, Beatriz | Albentosa, Marina
MPs' uptake and tissue accumulation were investigated in mussel exposed to a single dose (2.85 mg ind−1, 3 mg l−1) of a heterogeneous mixture of irregularly shaped particles of HDPE (mainly ≤10 μm), followed by a 7 days depuration period. The results showed that mussels efficiently cleared MPs from water during exposure, and that MPs were accumulated in digestive gland and gills during depuration. In digestive gland, the amount and size of the MPs accumulated decreased with time, indicating a slower processing and elimination of small MPs than of larger ones. In gills, MPs' burdens increased with time, the MPs accumulated were the smallest ones, suggesting the translocation of small MPs from the digestive system to the gills. The hazardous potential of the smaller fraction of MPs (≤4 μm) underlined that more focus should be directed towards the accumulation and effects of this fraction of MPs in the marine environment. | Sí
اظهر المزيد [+] اقل [-]Heavy metal contamination status in soil-plant system in the Upper Mersey Estuarine Floodplain, Northwest England النص الكامل
2019
Enya, Osim | Lin, Chuxia | Qin, Junhao
Globally, soil contamination by heavy metals is common in estuarine floodplains. A study was conducted to assess heavy metal contamination in the soil-plant system in Mersey estuarine floodplain, North West England. Representative composite soil samples and plant samples were collected from nine identified land use types across the study area. Various fraction of heavy metals in soils and plant tissue-borne heavy metals were determined. The results show that the study area has elevated concentrations of As, Cr, Cu, Pb and Zn. Heavy metal concentration in soils was generally higher in the lowlying areas than in the upland portions. There was a trend that concentration of heavy metals increased with increasing depth due to de-industrialisation in the upper catchment. The soil contamination resulted in elevated concentration of heavy metals in the grazed plants, which could pose a risk to wild animals, grazing animals and people who consume the grazing animal meat.
اظهر المزيد [+] اقل [-]Mesozooplankton characterization surrounding anthropogenic sewage inputs in the southeastern eutrophic Brazilian estuary of Guanabara Bay النص الكامل
2019
Maciel, O.L.C. | Almeida, E.V.
Zooplankton assembly was characterized during the spring tide near a submarine outfall that discharges raw sewage directly into the southeastern portion of Guanabara Bay, near the Niterói, a highly urbanized center. The rain period directly influences water surface temperature and salinity, as has been previously observed in this bay. Dissolved oxygen (DO) and biochemical oxygen demand (BOD) were within the concentrations stipulated by the Brazilian legislation. The low chlorophyll a values observed herein may be associated with a nutritional imbalance to which phytoplankton may be subjected, observed through the carotenoid/chlorophyll ratio, which probably reflects zooplankton community composition. Twenty major zooplanktonic taxonomic groups were recorded, with a predominance of holoplanktonic taxa, mainly copepods. Mean zooplankton density and composition were in agreement with other studies in the region, however, these community characteristics at each of the sampling stations appear to be related to the urbanization degrees of each Niterói neighborhood.
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