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Assessment of impacts to the sequence of the tropical cyclone Nisarga and monsoon events in shoreline changes and vegetation damage in the coastal zone of Maharashtra, India Полный текст
2022
Mishra, Manoranjan | Kar, Dipika | Santos, Celso Augusto Guimarães | Silva, Richarde Marques da | Das, Prabhu Prasad
The tropical cyclones impact both the eastern and western coasts of India, causing severe socio-environmental problems. This study analyzed shoreline changes and vegetation degradation caused by cyclone Nisarga and monsoon events in Maharashtra coastal zone and Mumbai region, India. In this study, the shoreline change was studied using the Net Shoreline Movement (NSM) statistical technique embedded in the digital shoreline analysis system (DSAS) tool. The effects of the cyclone on the vegetation were mapped using the Normalized Difference Vegetation Index (NDVI), Enhanced Vegetation Index (EVI), and the rainfall distribution from Global Precipitation Measurement (GPM) data. The correlation between rainfall data and vegetation loss was analyzed using geographically weighted regression. The results also show that 90% of the events were concentrated in the 80–300 mm classes, being classified as sudden increases. This cyclone caused erosion in 56.32% of the shoreline; the highest erosion level was observed along the coastal zone of Maharashtra (near Mumbai city). Cyclone Nisarga has also impacted the vegetation loss most prominently in the region, with mean EVI in pre-cyclone equal to 0.4 and post-cyclone equal to 0.2. These eco-physical studies using geospatial technology are needed to understand the behavior of changes in shoreline and vegetation and can also help coastal managers plan for resilient coastal systems after the passage of tropical cyclones.
Показать больше [+] Меньше [-]Occurrence and sources of microplastics and polycyclic aromatic hydrocarbons in surface sediments of Svalbard, Arctic Полный текст
2022
Lin, Yan | Cen, Zhengnan | Peng, Jinping | Yu, Huimin | Huang, Peng | Huang, Qinghui | Lu, Zhibo | Liu, Mengyang | Ke, Hongwei | Cai, Minggang
Due to the distinct environment condition and geographic location, Svalbard has been recognized as a potential pollution reservoir in the Arctic. In this study, 8 surface sediment samples were collected from two fjords in Svalbard (Kongsfjorden and Rijpfjorden) in 2017, and they were searched for microplastics and polycyclic aromatic hydrocarbons (PAHs). PAHs were also investigated in 10 soil samples of Ny-Ålesund for local anthropogenic source analysis. The level of microplastics and other anthropogenic particles ranged from not detected (ND) to 4.936 particles/kg dry weight (DW). Fiber was the only shape of the microplastics found and three polymers (polyester, rayon and cellulose) were detected, which suggested that fisheries-related debris and textile materials were possible sources of microplastics and anthropogenic particles. For PAHs, the level of ∑₂₆PAH was 9.2 ng/g to 67.1 ng/g (DW), and were dominated by lnP and BghiP, indicating petroleum combustion source. Further analysis revealed that traffic emissions from cars and diesel combustion from a local power plant were major sources of PAHs in soils of Ny-Alesund, while traffic emissions from ships were the dominate source of PAHs in sediments of Kongsfjorden and Rijpfjorden. A higher level of PAHs was observed in Ny-Alesund, confirming an anthropogenic input, while transport via ocean currents might contribute to the higher abundance of microplastics in Rijpfjorden. Further research and even long-term observation of pollutants are needed to fully understand the pollution status in polar regions.
Показать больше [+] Меньше [-]Algal turf structure and composition vary with particulate loads on coral reefs Полный текст
2022
Arjunwadkar, Chaitanya V. | Tebbett, Sterling B. | Bellwood, David R. | Bourne, David G. | Smith, Hillary A.
Algal turfs trap and retain particulates, however, little is known about the relationship between particulate accumulation and taxonomic composition of algal turfs. We investigated how particulate mass related to algal turf structure (length and density) and community composition (taxonomic and functional) on two disparate reefs. Particulate mass was positively related to algal turf length. By contrast, the relationship between particulate mass and turf density was more complex and followed a negative parabolic shape; density increased with particulate mass before stabilising and then declining. Community analyses showed taxonomic, but not functional group compositions differed significantly between reefs and with increasing particulate mass. Our results suggest high loads of particulates accumulated in algal turfs are related to a longer, lower density turf structure, typified by filamentous forms such as Cladophora. Changes in algal turf structure and composition could have a variety of bottom-up influences on coral reef ecosystems.
Показать больше [+] Меньше [-]Depuration of anthropogenic particles by Pacific oysters (Crassostrea gigas): Feasibility and efficacy Полный текст
2022
Covernton, Garth A. | Dietterle, Maggie | Pearce, Christopher M. | Gurney-Smith, Helen J. | Dower, John F. | Dudas, Sarah E.
Anthropogenic particles (APs) generated from both natural and synthetic materials are widespread in the aquatic environment and contaminate seafood products, including shellfish. Depuration, involving the placement of filter-feeding shellfish in clean water for a period of time, often several days, is used to reduce contaminant concentrations, but the practicality of its use by the shellfish industry for APs has not yet been examined. In the present study, cultured adult Pacific oysters (Crassostrea gigas) were depurated for 10 days in a facility with limited airflow and filtered seawater. On average, there was a 73 % reduction in oyster AP concentration after 5 days, but no further reduction at 10 days, potentially due to the difficulty in depurating some particles or to re-contamination from the experimental environment. Long-term feasibility for industry will depend on future guidelines for safe AP consumption levels and the practicality and financial feasibility of creating and running clean facilities.
Показать больше [+] Меньше [-]Small recreational boats: a ubiquitous source of sound pollution in shallow coastal habitats Полный текст
2022
Sound from small recreational boats spans a wide range of frequencies and source levels, but the degree to which this impacts the soundscapes of shallow coastal habitats is poorly understood. Here, long-term passive acoustic recordings at five shallow coastal sites, including two MPAs, were used to quantify spatio-temporal variation in small boat sound and its effect on the soundscape. Boats were detected almost every day at each site, irrespective of protection status, significantly elevating the low-frequency (100–800 Hz) component of the soundscape. This frequency band is used by many species for communication, orientation, and predator avoidance. Therefore, highlighting the potential for small boat sound to alter soundscapes and mask cues. Existing tools for monitoring sound pollution are targeted at sound from shipping. These data highlight that the broadband and highly variable sound emitted by small boats must be considered when evaluating anthropogenic impacts on coastal marine ecosystems worldwide.
Показать больше [+] Меньше [-]A new assessment of the algal biomass of green tide in the Yellow Sea Полный текст
2022
Yuan, Chao | Xiao, Jie | Zhang, Xuelei | Zhou, Jian | Wang, Zongling
The annually recurring Yellow Sea green tide causes significant economic, social, and ecological impacts in China. Currently, the magnitude of Yellow Sea green tide is usually evaluated according to the snap shot maximum algal coverage area or artificially removed algal biomass. However, this method ignores growth of the alga Ulva prolifera and thus needs improvement. We build a model to predict algal growth in drifting from upstream and the potential muaximum biomass of green tide. The results suggest that the potential maximum biomass is significantly higher than those estimated merely from maximum algal coverage area, particularly for years with extended period of algal loading in the upstream. Our method improves the evaluation of the magnitude of green tide and provides a scientific basis for developing effective countermeasures to reduce the persistent disaster.
Показать больше [+] Меньше [-]The potential of saltmarsh halophytes for phytoremediation of metals and persistent organic pollutants: An Australian perspective Полный текст
2022
Roe, Rebecca A.L. | MacFarlane, Geoff R.
Persistent organic and inorganic pollutants are among the most concerning pollutants in Australian estuaries due to their persistent, ubiquitous, and potentially toxic nature. Traditional methods of soil remediation often fall short of practical implementation due to high monetary investment, environmental disturbance, and potential for re-contamination. Phytoremediation is gaining traction as an alternative, or synergistic mechanism of contaminated soil remediation. Phytoremediation utilises plants and associated rhizospheric microorganisms to stabilise, degrade, transform, or remove xenobiotics from contaminated mediums. Due to their apparent cross-tolerance to salt, metals, and organic contaminants, halophytes have shown promise as phytoremediation species. This review examines the potential of 93 species of Australian saltmarsh halophytes for xenobiotic phytoremediation. Considerations for the practical application of phytoremediation in Australia are discussed, including mechanisms of enhancement, and methods of harvesting and disposal. Knowledge gaps for the implementation of phytoremediation in Australian saline environments are identified, and areas for future research are suggested.
Показать больше [+] Меньше [-]Entanglement of Steller sea lions (Eumetopias jubatus) in man-made marine debris on Tyuleniy Island, Sea of Okhotsk Полный текст
2022
Kuzin, Alexey E. | Trukhin, Alexey M.
The present report provides data on entanglement of Steller sea lions (SSL) in marine debris on Tyuleniy Island, Sea of Okhotsk. The frequency of entanglement depending on the material, sex, and age of animals was estimated. A total of 133 SSL were recorded as having debris on their bodies, or an average of 22.2 individuals per year. The relative rate of entanglement over the observation years ranged from 1.48 to 1.97% of their total number. The entangled individuals were both males and females of all ages, but young males constituted the largest proportion among them (5.2%). The entangled SSL most frequently (43.2%) had neck collars (the material is not defined) and, less frequently, packaging bands (23.4%), nets (17.7%), and other debris. Most of marine litter found on SSL is associated with commercial fishing activities. On Tyuleniy Island, the rate of SSL entanglement is higher than in the eastern part of the species' range.
Показать больше [+] Меньше [-]A brief overview of current approaches for underwater sound analysis and reporting Полный текст
2022
van Geel, Nienke C.F. | Risch, Denise | Wittich, Anja
Soundscapes have substantially changed since the industrial revolution and in response to biodiversity loss and climate change. Human activities such as shipping, resource exploration and offshore construction alter natural ecosystems through sound, which can impact marine species in complex ways. The study of underwater sound is multi-disciplinary, spanning the fields of acoustics, physics, animal physiology and behaviour to marine ecology and conservation. These different backgrounds have led to the use of various disparate terms, metrics, and summary statistics, which can hamper comparisons between studies. Different types of equipment, analytical pathways, and reporting can lead to different results for the same sound source, with implications for impact assessments. For meaningful comparisons and derivation of appropriate thresholds, mitigation, and management approaches, it is necessary to develop common standards. This paper presents a brief overview of acoustic metrics, analysis approaches and reporting standards used in the context of long-term monitoring of soundscapes.
Показать больше [+] Меньше [-]Effects of the antidepressant paroxetine on migratory behaviour of meiobenthic nematodes: Computational and open experimental microcosm approach Полный текст
2022
Ishak, Sahar | Allouche, Mohamed | Harrath, Abdel Halim | Alwasel, Saleh | Beyrem, Hamouda | Pacioglu, Octavian | Badraoui, Riadh | Boufahja, Fehmi
An open experimental setup was established in order to explore the toxic effects of the antidepressant paroxetine on meiobenthic nematodes. Three types of microcosms made from polyvinyl chloride tubes, each comprising two sediments compartments (upper and lower), were used in a laboratory experiment for 15 days. The experimental setup targeted the migratory behaviour of the nematofauna from the above compartments, which were exposed to paroxetine (0.4 and 40 μg.l⁻¹), towards below compartments. The univariate indices significantly decrease in the contaminated compartments compared to controls. Multivariate analyses revealed also significant taxonomic dissimilarities between contaminated and uncontaminated compartments. Furthermore, SIMPER functional outcomes highlighted a significant decrease in 2A feeding groups, ‘co’ tail shape, 1–2 mm interval length, ‘cr’ amphid shape, and c-p2 life history in contaminated compartments. Computational approach showed that paroxetine bound GLD-3 and SDP with high affinities, which together with molecular interactions and toxicokinetics satisfactorily explain the experimental results.
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