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Результаты 1781-1790 из 5,149
Differential impact of marine debris ingestion during ontogenetic dietary shift of green turtles in Uruguayan waters Полный текст
2018
Vélez-Rubio, G.M. | Teryda, N. | Asaroff, P.E. | Estrades, A. | Rodriguez, D. | Tomas, J.
Anthropogenic debris ingestion has been reported for green turtles in all their life stages worldwide. The aim of the present study is to evaluate the marine debris ingestion by green turtles stranded in Uruguayan coast between 2005 and 2013. Debris items were categorized and quantified by frequency of occurrence, relative weight, volume and number of items. A total of 96 dead stranded turtles were analyzed and 70% presented debris in their guts. The majority of debris found were plastic, being hard plastics the most abundant in weight. We found no differences in debris ingestion in stranded turtles a long the Uruguayan coast. However we detected a negative correlation between the presence of debris and turtle's size. Smaller turtles are new recruits to neritic grounds indicating that the early juvenile stage of this species is the most vulnerable to this threat in the Southwestern Atlantic.
Показать больше [+] Меньше [-]Underwater noise from airplanes: An overlooked source of ocean noise Полный текст
2018
Erbe, Christine | Williams, Rob | Parsons, Miles | Parsons, Sylvia K. | Hendrawan, I Gede | Dewantama, I Made Iwan
The effects of underwater noise pollution on marine life are of increasing concern. Research and management have focussed on the strongest underwater sound sources. Aerial sound sources have understandably been ignored as sound transmits poorly across the air-water interface. However, there might be situations when air-borne noise cannot be dismissed. Commercial passenger airplanes were recorded in a coastal underwater soundscape exhibiting broadband received levels of 84–132 dB re 1 μPa rms. Power spectral density levels of airplane noise underwater exceeded ambient levels between 12 Hz and 2 or 10 kHz (depending on site) by up to 36 dB. Underwater noise from airplanes is expected to be audible to a variety of marine fauna, including seals, manatees, and dolphins. With many of the world's airports lying close to the coast, it is cautioned that airplane noise not be ignored, in particular in the case of at-risk species in small, confined habitats.
Показать больше [+] Меньше [-]Ecological risk assessment of heavy metals in surface sediments from the Gorgan Bay, Caspian Sea Полный текст
2018
Gholizadeh, Mohammad | Patimar, Rahman
This study was conducted to investigate the amounts of heavy metals in the Gorgan Bay. For this purpose, 12 sediment samples were taken from the Gorgan Bay, and then, the amounts of metals were determined using the ICP-OES spectrometer. Accordingly, the average value of the metals aluminum (Al), arsenic (As), chromium (Cr), copper (Cu), nickel (Ni), lead (Pb), vanadium (V), and zinc (Zn) was 1.3 ± 0.2%, 8.1 ± 3.8 ppm, 17.9 ± 4.3 ppm, 16.8 ± 4.2 ppm, 16.6 ± 4 ppm, 7.4 ± 1.3 ppm, 17.6 ± 3.7 ppm, and 29.5 ± 6.9 ppm, respectively. According to the Pearson test, a significant correlation was observed among all metals (except arsenic) in this study (P < 0.01), which indicates that the source of the metals (human or natural) is the same in this gulf. There was also a positive correlation between organic matter and all metals (except lead and vanadium) (P > 0.05). This positive correlation probably indicates that these metals enter the aquatic environment along with organic matter or that they are of the same origin (organic matter and metals). On the basis of the PER index, all the measured metals had a low ecological risk at all stations.
Показать больше [+] Меньше [-]Fluorescence photobleaching of microplastics: A cautionary tale Полный текст
2018
Sullivan, Kelley D. | Gugliada, Valerie
Fluorescence microscopy is an important step in visual identification of microplastics and is used to highlight white and transparent plastics that are otherwise easily missed or misidentified. Investigators using fluorescence must proceed with caution, however, as fluorescence photobleaching can significantly reduce the fluorescence output of samples within experimentally relevant time frames. We report on the photobleaching rate and subsequent lack of fluorescence recovery of five common plastics. Our results reveal statistically different photobleaching rates across plastic types. In the best-case scenario of low illumination intensity and a robust plastic, initial fluorescence intensity decayed by 10% in just 11(3) s and by 33% in 230(40) s. In all cases, fluorescence failed to recover more than 13(8)% in 3 h. These results indicate that significant bleaching can occur while searching a sample for plastics to identify and that the lack of recovery can compromise samples for further study.
Показать больше [+] Меньше [-]A baseline study on trace element based sediment pollution and potential ecological risk of reef sediments of Musal, Manoli and Manoli putti Islands, Gulf of Mannar, India Полный текст
2018
Saravanan, P. | Pradhap, D. | Krishnakumar, S. | Silva, Judith D. | Vidyasakar, A. | Sackaria, Merin | Godson, Prince S. | Ār̲umukam, Kā. | Magesh, N.S.
The aim of the present study is to assess the baseline level of the trace element, sediment pollution and potential ecological risk of reef associated sediments of Musal, Manoli and Manoli putti Islands, Gulf of Mannar, India. The grain size distribution of the sediments is chiefly controlled by corals and broken shell debris. The distribution of lithoclastic fractions and element concentration are most probably derived from longshore sediment transport and fluvial process from nearby mainland. The enrichment of organic matter is chiefly controlled by mangrove litters and sea grasses. The concentration of lead in the marine sediments is subjected to sediment matrix, vicinity of the local pollutant sources and distance from the mainland coast. The ecological risk assessment clearly reveals that the sediments belong to the low risk category.
Показать больше [+] Меньше [-]Elemental concentration based potential ecological risk (PER) status of the surface sediments, Pulicat lagoon, Southeast coast of India Полный текст
2018
Saravanan, P. | Krishnakumar, S. | Pradhap, D. | Silva, Judith D. | Ār̲umukam, Kā. | Magesh, N.S. | Srinivasalu, S.
Eighty-three surface sediments were collected to investigate the element concentration based sediment pollution and potential ecological risk status of the Pulicat lagoon, southeast coast of India. The textural characteristics, Fe and Mn concentration in the surface sediments are chiefly controlled by the confluence of riverine inputs and vicinity of the marine environment. The varied distribution of CaCO₃ concentration is due to the depth of the lagoon followed by the sand and silty sand characteristics of the substratum. The surface sediments are derived from riverine sources. Sediment Pollution Index (SPI), Potential Ecological Risk Index of the sediments suggests that they are falling under less polluted and low potential ecological risk category.
Показать больше [+] Меньше [-]Hexabromocyclododecanes (HBCDs) in fish: Evidence of recent HBCD input into the coastal environment Полный текст
2018
Sun, Runxia | Luo, Xiaojun | Zheng, Xiaobo | Fanhuolaoren, | Peng, Pingan | Li, Qing X. | Mai, Bixian
Hexabromocyclododecanes (HBCDs) are flame retardants and emerging persistent organic pollutants. In the present study, α-, β-, and γ-HBCDs were measured in several fish species from rivers and an electronic waste (e-waste) recycling site in Pearl River Delta, South China. The concentrations of HBCDs were 12.8 to 640, 5.90 to 115, and 34.3 to 518ng/g lipid weight (lw) in mud carp (Cirrhinus molitorella), tilapia (Tilapia nilotica), and plecostomus (Hypostomus plecostomus), respectively. Plecostomus showed the highest HBCD concentrations among three fish species. The contributions of α-HBCD to total HBCDs were 78% to 97%, 93% to 99%, and 87% to 98% in carp, tilapia, and plecostomus, respectively. Fish samples from a harbor and the e-waste site exhibited the highest HBCD concentrations among all samples. The HBCD concentrations were not significantly correlated with the gross domestic product or population data. e-Waste recycling activities, harbor construction, and shipment might be recent HBCD sources.
Показать больше [+] Меньше [-]Erosion as a possible mechanism for the decrease of size of plastic pieces floating in oceans Полный текст
2018
Resmeriță, Ana-Maria | Coroaba, Adina | Darie, Raluca | Doroftei, Florica | Spiridon, Iuliana | Simionescu, Bogdan C. | Navard, Patrick
A sea water wave tank fitted in an artificial UV light weathering chamber was built to study the behaviour of polypropylene (PP) injected pieces in close ocean-like conditions. In air, the same pieces sees a degradation in the bulk with a decrease of mechanical properties, a little change of crystal properties and nearly no change of surface chemistry. Weathering in the sea water wave tank shows only a surface changes, with no effect on crystals or mechanical properties with loss of small pieces of matter in the sub-micron range and a change of surface chemistry. This suggests an erosion dispersion mechanism. Such mechanism could explain why no particle smaller than about one millimeter is found when collecting plastic debris at sea: there are much smaller, eroded from plastic surfaces by a mechano-chemical process similar to the erosion mechanism found in the dispersion of agglomerate under flow.
Показать больше [+] Меньше [-]Physical characteristics of free-living sea turtles that had and had not ingested debris in Microregion of the Lakes, Brazil Полный текст
2018
Rosolem Lima, Samara | da Silva Barbosa, João Marcos | Gomes Ferreira Padilha, Felipe | Veiga Saracchini, Paula Gabrielle | de Almeida Braga, Maurício | da Silva Leite, Juliana | Reis Ferreira, Ana Maria
The ingestion of detritus by sea turtles results in high mortality and morbidity. The objective of this study was to describe the characteristics of free-living sea turtles that ingested anthropogenic inorganic detritus in comparison to those that did not. A total of 186 necropsy files were analyzed in marine turtles from the beaches of the Microregion dos Lagos, Rio de Janeiro. Among the turtles that ingested detritus, the mean turtle was female and cachectic, with a carapace length of 36,6 cm, detritus accumulated in the large intestine, and fecal compaction. It seems most likely that's low food transit, combined with the multiplicity of ingestion, favored the accumulation of detritus. This ingestion resulted in cachexia associated with fecal compaction, since the greatest accumulation was in the large intestine. The intake of detritus by turtles was not punctual but continuous. These studies demonstrated the vulnerability of these animals to environmental pollution.
Показать больше [+] Меньше [-]Microplastics analysis in Malaysian marine waters: A field study of Kuala Nerus and Kuantan Полный текст
2018
Khalik, Wan Mohd Afiq Wan Mohd | Ibrahim, Yusof Shuaib | Tuan Anuar, Sabiqah | Govindasamy, Sharumathiy | Baharuddin, Nor Fadilah
The first report on the emergence of microplastic in Malaysian marine waters was documented in this study. Water samples were collected from two regions, namely Kuala Nerus and Kuantan port, as the representatives of different anthropogenic activities. Identification of microplastic was performed based on physical characteristics (colour, shape, density) and chemical characterisation (ATR-FTIR analysis) for a functional group of polymers. Fragment type, black or grey colour and high density (>1.02 g cm−3) of microplastic were the most prevalent characteristics found in both areas. Two principal components (density and colour) rendered explained about 95.3% (Kuantan) and 95.6% (Kuala Nerus) of the total variance. Six possible polymer materials were identified, namely polyester, polystyrene, polyamide, polyvinyl chloride, polypropylene, and polyethylene. The findings of the study provided good baseline information on marine debris issue in Malaysia.
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