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Our paper reports results of speciation analysis of arsenic(III) and (V) in the exchangeable fraction of the marine sediments from the Andaman Sea. The sediments were collected from the coastal zone at the coast of Thailand affected by the 2004 tsunami waves. The samples were extracted with phosphate buffer and then subjected to determination of inorganic species of arsenic by HPLC-HG-AAS. A correlation between the contents of arsenic and grain size of the sediments was found. Higher content of As(III) established in fine grain fraction of the sediment can suggest its deposition by tsunami.
Organotin compounds are widely used in almost all sectors of industry. Antifouling paints, which were applied to ship hulls to protect from fouling organisms, are the main source of TBT and TPhT derivatives loaded into the sea. The global ban on the use of these compounds in antifouling systems was introduced by the IMO in 2001. However, the ban did not solve the problem of the use of alternatives to TBT in the ship industry. Moreover, the issue of storing the organotins-containing dredged spoils at sea still remains unresolved. The pollution load deposited in port sediments may become an additional threat to the organisms that dwell in a given water basin. In such cases, it is necessary to establish appropriate norms for the quality classification of dredged spoils. Unfortunately, detailed guidelines concerning the disposal of dredged spoils are still lacking.
Mono- and dimethylphenanthrenes were determined in recent (0–10 cm) sediments collected at about 30 stations in the southern Baltic Sea from 1995 to 2001. The stations were located in the Szczecin Lagoon, the Pomeranian Bay, the Bornholm Deep, the open sea (without the Bornholm and Gdańsk Deeps), the Gdańsk Deep, and the Gulf of Gdańsk including the Wisła (Vistula) Lagoon. The results were related to the unsubstituted PAH content. The annual load of methylphenanthrenes in relation to unsubstituted PAHs in the Rivers Odra and Wisła was estimated. Methylphenanthrenes are more abundant in the Odra estuary than in the Wisła estuary, and more abundant in the coastal sediments than in the open sea sediments. The results indicate that methylphenanthrenes related to the lower molecular, unsubstituted PAHs are a good measure of petrogenic pollution in the southern Baltic.
Corals are known to flourish in various turbid environments around the world. The quantitative distinction between clear and turbid water in coral habitats is not well defined nor are the amount of sediment in suspension and rates of sedimentation used to evaluate the condition of reef environments well established. This study of sedimentation rate, sediment composition and pH, OC deposition was on a fringing reef flat off Thoothukudi and Vembar group of islands, Gulf of Mannar, India. In the present study the sedimentation rate ranged from 1.97 mg/cm2/day to 12.31 mg/cm2/day. The percentage of sand in the sediment was higher than silt and clay. The organic carbon level in all the study stations ranged from 0.03 to 2.54. The sediment pH of the six studied stations was highly acidic in nature at all the study sites in the Gulf of Mannar.
Measurements were made of sediment characteristics, benthic microbial activity and optimum temperature for sulfate reduction at Signy Island, South Orkney Islands, Antarctica. There was little evidence to support any seasonal variation in oxygen penetration of surface sediments. Oxygen penetrated to only 1.5 to 3 mm throughout the year, despite bioturbation from a dense amphipod population. The distribution of acid volatile sulfides increased with depth below 1 cm and above this, surface sediments were lighter in colour and contained fewer sulfides. The rates of sulfate reduction increased during winter under sea-ice cover, and remained high after ice break up. Seasonal water temperature was relatively constant between -1.8 and 0.5°C. Optimum temperature for anaerobic sediment respiration was investigated using different substrates and was found to be in the range 17-27°C, suggesting that sulfate reducing bacteria are psychrotolerant as they were inhibited by low temperatures.
Tsunami deposits are often characterized by specific diatom assemblages, which may indicate sediment provenance and help identify paleotsunami deposits. In the present study diatom assemblages were studied in tsunami deposits left by the 2004 tsunami in Thailand, as well as in beach sediments, inner shelf marine sediments and freshwater ponds and streams. The assemblages in tsunami deposits had chaotic structure and consisted of species found in all the studied habitats, suggesting erosion of terrestrial and marine sediments by tsunami. The diatom frustules in tsunami deposits were generally rare and often damaged due to excessive wave force. The most common identified species were Amphora turgida Gregory, Cocconeis scutellum Ehrenberg, Diplomenora cocconeiformis (Schmidt) Blazé, Eunotogramma marinum (W. Smith) Peragallo (typical for benthos of marine and brackish environments), and taxa common in freshwaters, including Cyclotella ocellata Pantocsek, Cocconeis placentula Ehrenberg and Encyonema silesiacum (Bleish) D.G. Mann.
We examine the composition and levels of organic contaminants (PAHs, PCB, HCB) in four sediment cores collected from the Barents Sea. We assess the influence of temporal variations in contaminant supplies and post-depositional reworking on contaminant distribution. Anthropogenic levels of P12PAH reached 95 ng g−1, higher inventories dominated by BKF were observed at southern stations, while northern stations exhibited lower inventories with PHE as the dominant compound. The PCB composition was similar at all stations dominated by CB101, 138 and 153. P7PCB concentrations were higher at northern stations. The observed composition and spatio-temporal pattern of organic contaminants is in accordance with long-range transport supplies.
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