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Результаты 1431-1440 из 4,291
Marine debris in five national parks in Alaska
2017
Polasek, L. | Bering, J. | Kim, H. | Neitlich, P. | Pister, B. | Terwilliger, M. | Nicolato, K. | Turner, C. | Jones, T.
Marine debris is a management issue with ecological and recreational impacts for agencies, especially on remote beaches not accessible by road. This project was implemented to remove and document marine debris from five coastal National Park Service units in Alaska. Approximately 80km of coastline were cleaned with over 10,000kg of debris collected. Marine debris was found at all 28 beaches surveyed. Hard plastics were found on every beach and foam was found at every beach except one. Rope/netting was the next most commonly found category, present at 23 beaches. Overall, plastic contributed to 60% of the total weight of debris. Rope/netting (14.6%) was a greater proportion of the weight from all beaches than foam (13.3%). Non-ferrous metal contributed the smallest amount of debris by weight (1.7%). The work forms a reference condition dataset of debris surveyed in the Western Arctic and the Gulf of Alaska within one season.
Показать больше [+] Меньше [-]Laboratory and field magnetic evaluation of the heavy metal contamination on Shilaoren Beach, China
2017
Wang, Yonghong | Huang, Qinghui | Lemckert, Charles | Ma, Ying
This study uses magnetic measurements to evaluate the heavy metal contamination of the surface sediments on Shilaoren Beach. The values of the laboratory magnetic measurements have a positive relationship with the concentrations of Fe, Mn, Cr, Ni, As and Pb. The field magnetic parameter provides an effective and rapid method for evaluating the distribution and dispersal of heavy metal. Sediments with higher heavy metal contents generally accumulate near higher and lower tide lines on the beach, reflecting the control of waves and tides. The sewage and stormwater outlets are the primary sources of the heavy metal contamination. Variations in seasonal waves and winds affect the sediment transport and the heavy metal distribution patterns. Based on the Australian ISQG-Low sediment quality criteria, Fe, Mn and Cr generally exhibit intermediate accumulation levels, whereas Pb and Zn exhibit higher accumulation levels because of the socioeconomic status of the area surrounding the beach.
Показать больше [+] Меньше [-]Spatial distribution and sources of organic matter and pollutants in the SE Mediterranean (Levantine basin) deep water sediments
2017
Astrahan, P. | Silverman, J. | Gertner, Y. | Herut, B.
A study of deep sea sediment quality was conducted at 52 stations off the Mediterranean coast of Israel (50–1900m depth). Total Organic Carbon (TOC), Polycyclic Aromatic Hydrocarbons (∑PAHs), Poly Chlorinated Biphenyls (∑PCBs) ranged between 0.58 and 1.44%, 12–190 and <0.3–7.7μgkg−1, respectively. The TOC distribution indicated the Nile delta as an important source of organic matter and the important effect of topography on deposition patterns in this region. PCBs and PAHs quantitative levels were associated with nearby gas well drilling (well below environmental criteria) and dredge-material dumping sites. A significant correlation between these pollutants and TOC was found in the southernmost stations suggesting a common source. PAHs isomer ratios in most of the stations indicated a petrogenic source, while the contribution of pyrogenic sources appears to be very small. These findings form a sound baseline for assessing the potential impact of future deep sea drilling activities that are expected to increase significantly in the Eastern Mediterranean basin.
Показать больше [+] Меньше [-]Chlorine dioxide as an alternative antifouling biocide for cooling water systems: Toxicity to larval barnacle Amphibalanus reticulatus (Utinomi)
2017
Venkatnarayanan, Srinivas | Sriyutha Murthy, P. | Kirubagaran, Ramalingam | Venugopalan, Vayalam P.
Chlorine dioxide (ClO2) is seen as an effective alternative to chlorine, which is widely used as an antifouling biocide. However, data on its efficacy against marine macrofoulants is scanty. In this study, acute toxicity of ClO2 to larval forms of the fouling barnacle Amphibalanus reticulatus was investigated. ClO2 treatment at 0.1mg/L for 20min elicited 45–63% reduction in naupliar metamorphosis, 70% inhibition of cyprid settlement and 80% inhibition of metamorphosis to juveniles. Increase in concentration to 0.2mg/L did not result in any significant difference in the settlement inhibition or metamorphosis. Treatment with 0.2mg/L of ClO2 elicited substantial reduction in the settlement of barnacle larvae compared to control. The study indicates the possibility of using ClO2 as an alternative antifouling biocide in power plant cooling water systems. However, more work needs to be done on the environmental effects of such switchover, which we are currently undertaking.
Показать больше [+] Меньше [-]The use of rockfish Sebastiscus marmoratus as a sentinel species to assess petroleum hydrocarbons pollution: A case study in Quanzhou Bay, China
2017
Bo, Jun | Zheng, Ronghui | Kuang, Weiming | Hong, Fukun | Xie, Qing | Zhang, Yusheng
To monitor the biological effects of marine pollution, choosing a native fish species and establishing suitable biomarkers are required. In this study, the full-length cDNA of cyp1a1 was cloned from Sebastiscus marmoratus (SM-CYP1A1). Then the dose-response and time-course induction of hepatic CYP1A1 mRNA by the crude oil water-soluble fraction (WSF) were determined. Subsequently, SM-CYP1A1 mRNA was applied to investigate the biological effect of petroleum hydrocarbon pollution in Quanzhou Bay, China. The transcription levels of hepatic CYP1A1 were significantly elevated in fish caged in the polluted sites for 2weeks compared with those of the reference site, which were correlated with the concentrations of petroleum hydrocarbon and polycyclic aromatic hydrocarbon (PAH) in the surface seawaters. The results suggest that S. marmoratus is a potential sentinel organism to monitor marine pollutants and the hepatic CYP1A1 mRNA can serve as a sensitive biomarker to organic xenobiotics in aquatic environments.
Показать больше [+] Меньше [-]Offshore iron sand extraction in New Zealand: Potential trace metal exposure of benthic and pelagic biota
2017
Vopel, Kay | Pook, Chris | Wilson, Peter | Robertson, John
Plans to exploit an offshore source of iron sand in South Taranaki Bight (STB), New Zealand, caused concerns that such exploitation may expose benthic and pelagic biota to elevated trace metal concentrations. We conducted dilute-acid extractions and standard elutriate tests to investigate the potential of this exploitation to (1) create a new seafloor with elevated trace metal content, (2) mobilise trace metals during iron sand extraction and, (3) enrich the returning process seawater, which feeds iron sand through mills, with trace metals. We found that recruits of freshly uncovered sediment may encounter higher-than-natural concentrations of cadmium, nickel and chromium (but not of copper, lead, and zinc) and propose to investigate the bioavailability of these metals. Elutriate test with raw and milled iron sand revealed that, for nickel and copper, dilution of the process seawater may be required to meet the local water quality guideline. We argue that this dilution can be achieved by adjustment of the mass and seawater balance of the offshore extraction process.
Показать больше [+] Меньше [-]Factor associated variations in the home range of a resident Adriatic common bottlenose dolphin population
2017
Rako-Gospić, Nikolina | Radulović, Marko | Vučur, Tihana | Pleslić, Grgur | Holcer, Draško | Mackelworth, Peter
This study investigates the influence of the most dominant factors (association patterns, gender, natal philopatry and anthropogenic pressure) on the home range size of the 44 most resident common bottlenose dolphins (Tursiops truncatus) inhabiting the waters of the Cres-Lošinj archipelago (north Adriatic Sea, Croatia), a recently declared NATURA 2000 SCI. Results show that variations in home range patterns (MCP, 95% KDE and 50% KDE home range size) among the individual resident dolphins are primarily related to differences in gender and reflect the way in which different genders respond to external stressors. In addition, results confirm the seasonal influence of nautical tourism on both female and male dolphins through changes in their home range sizes. The overall results improve current knowledge of the main anthropogenic threats that should be taken into consideration when developing conservation measures to be applied to this Cres and Lošinj SCI.
Показать больше [+] Меньше [-]The impact of wastewater treatment effluent on microbial biomasses and diversities in coastal sediment microcosms of Hangzhou Bay
2017
Tao, Yile | Dai, Tianjiao | Huang, Bei | Wen, Donghui
Disposal of wastewater treatment plant (WWTP) effluent into sea, a typical anthropogenic disturbance, may influence many environmental factors and change the coastal microbial community structure. In this study, by setting up coastal sediment microcosms perturbed by WWTP effluent, the changes of microbial community structure under different degree of disturbances were investigated. Quantitative PCR (qPCR) and terminal restriction fragment length polymorphism (T-RFLP) were used to analyzed the biomass and biodiversity. High throughput sequencing analysis was used to identify the classification of the microorganisms. Our study suggested that low ratio of WWTP effluent may stimulate dominant species, which increase the biomass but decrease the biodiversity; while high ratio of WWTP effluent may depress all species, which decrease the biomass but increase the biodiversity. In other words, the impact was dose-dependent. The changes of microbial community structure may provide a metric for water environmental assessment and pollution control.
Показать больше [+] Меньше [-]Impact of habitat management on waterbirds in a degraded coastal wetland
2017
Wei, Pingping | Zan, Qijie | Tam, Nora F.Y. | Shin, Paul K.S. | Cheung, S.G. | Li, Mingguang
The loss of coastal wetlands in Hong Kong Mai Po Nature Reserve adversely affected wetland-depended species. To mitigate this impact, gei wai ponds were reconstructed according to a set of biodiversity management zones (BMZs). This study, based on Canonical Correspondence Analysis (CCA), investigated if waterbird distribution was related to BMZ characteristics. Based on habitat characteristics, ponds in the same BMZ generally clumped in the same quadrant or within a short distance on CCA scatter plots, indicating that a BMZ zone produced common habitat traits. Ponds in a close distance on the plot had similar bird abundance or community structure. Significant correlations were noted between the abundance of cormorants and tall tree, and between waders and bare ground areas within study ponds. This study indicated that the control of key habitat factors was important for the success of reconstruction of gei wais and management of waterbirds in Mai Po.
Показать больше [+] Меньше [-]Comparing different methods for fast screening of microbiological quality of beach sand aimed at rapid-response remediation
2017
Testolin, Renan C. | Almeida, Tito C.M. | Polette, Marcus | Branco, Joaquim O. | Fischer, Larissa L. | Niero, Guilherme | Poyer-Radetski, Gabriel | Silva, Valéria C. | Somensi, Cleder A. | Corrêa, Albertina X.R. | Corrêa, Rogério | Rörig, Leonardo R. | Itokazu, Ana Gabriela | Férard, Jean-François | Cotelle, Sylvie | Radetski, Claudemir M.
There is scientific evidence that beach sands are a significant contributor to the pathogen load to which visitors are exposed. To develop beach quality guidelines all beach zones must be included in microbiological evaluations, but monitoring methods for beach sand quality are relatively longstanding, expensive, laborious and require moderate laboratory infrastructure. This paper aimed to evaluate the microorganism activity in different beach zones applying and comparing a classical method of membrane filtration (MF) with two colorimetric screening methods based on fluorescein (FDA) and tetrazolium (TTC) salt biotransformation to evaluate a new rapid and low-cost method for beach sand microbiological contamination assessments. The colorimetric results can help beach managers to evaluate rapidly and at low cost the microbiological quality of different beach zones in order to decide whether remedial actions need to be adopted to prevent exposure of the public to microbes due to beach sand and/or water contamination.
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