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结果 1061-1070 的 3,189
Influence of nutrients pollution on the growth and organic matter output of Ulva prolifera in the southern Yellow Sea, China
2015
Zhou, Yuping | Tan, Liju | Pang, Qiuting | Li, Feng | Wang, Jiangtao
The influence of nutrients on the growth of Ulva prolifera was studied in the SYS by field experiments. The wet weight of U. prolifera gradiently increased from 11.94% to 25.92% in proportion to contents of DIN supply, which indicated DIN content was essentially decisive for the output of U. prolifera blooms. Continuous nutrient supply could promote the growth of U. prolifera, indicated by the increase of growth rate from 10.46% of the batch culture to 42.17% of the in situ culture. The higher P utilized rate in all treatments showed P was the potential limited factor for the growth of U. prolifera. Moreover, it was calculated about 4.1×105t organic matter was begot by U. prolifera in the whole Yellow Sea based on the statistical relationship between output of U. prolifera and DIN content. This work could be convenient to evaluate biomass and prepare enough tools to manage U. prolifera.
显示更多 [+] 显示较少 [-]Arsenic fractionation in estuarine sediments: Does coastal eutrophication influence As behavior?
2015
Sá, Fabian | Sanders, Christian J. | Patchineelam, Sambasiva Rao | Machado, Eunice da Costa | Lombardi, Ana Teresa
The Paranaguá Estuarine Complex (PEC) includes the naturally oligotrophic (NO) Mel Island which is surrounded by sea grasses, a naturally eutrophic (NE) Benito Inlet adjacent to mangrove wetlands and the highly impacted eutrophic (IE) Paranaguá Bay, home of one of Brazil’s largest ports. The results from this study indicate that reactive As and pyrite increase with sediment depth near Paranaguá port in the IE region. At the NE region, near a mangrove fringe, the reactive As, Fe, Mn and pyrite remained relatively high along the sediment column while near the sea grasses at NO the As contents were low. The degree of trace metal pyritization (DTMP) and the degree of pyritization (DOP) was highest at the IE site, slightly increasing with depth. These baseline results indicate that influence of trophic conditions and presence of marine vegetation may be directly related to As behavior in coastal systems.
显示更多 [+] 显示较少 [-]Modeling the dispersion of viable and total Escherichia coli cells in the artificial semi-enclosed bathing area of Santa Marinella (Latium, Italy)
2015
Bonamano, S. | Madonia, A. | Borsellino, C. | Stefanì, C. | Caruso, G. | De Pasquale, F. | Piermattei, V. | Zappalà, G. | Marcelli, M.
Coastal areas are strongly affected by episodes of fecal contamination due to polluted water inflows from inadequately treated sewages. The present study aims to investigate the dispersion of Escherichia coli in the artificial semi-enclosed bathing area of Santa Marinella (Latium, Italy) through in situ samplings carried out in summer 2012 and the application of a dynamic model. Collected samples were analyzed by the Culture-Based technique and the Fluorescent Antibody method in order to estimate both the viable culturable cells and the total E. coli population, respectively. The in situ datasets were used to test the proposed modeling approach and simulate the behavior of bacteria as particles subjected, or not, to decay. Next, the flushing time and the computation of the Microbiological Potential Risk Area allowed the evaluation of the contribution of physical and biological processes to coliform dispersion and the related potential risk for bathers.
显示更多 [+] 显示较少 [-]Relationship between the lability of sediment-bound Cd and its bioaccumulation in edible oyster
2015
Chakraborty, Parthasarathi | Ramteke, Darwin | Chakraborty, Sucharita | Chennuri, Kartheek | Bardhan, Pratirupa
A linkage between Cd speciation in sediments and its bioaccumulation in edible oyster (Crassostrea sp.) from a tropical estuarine system was established. Bioaccumulation of Cd in edible oyster increased with the increasing lability and dissociation rate constants of Cd-sediment complexes in the bottom sediments. Total Cd concentration in sediment was not a good indicator of Cd-bioavailability. Increasing trace metal competition in sediments increased lability and bioavailability of Cd in the tropical estuarine sediment. Low thermodynamic stability and high bioavailability of Cd in the estuarine sediment were responsible for high bioaccumulation of Cd in edible oysters (3.2–12.2mgkg−1) even though the total concentration of Cd in the bottom sediment was low (0.17–0.49mgkg−1).
显示更多 [+] 显示较少 [-]Potential oil spill risk from shipping and the implications for management in the Caribbean Sea
2015
Singh, Asha | Asmath, Hamish | Chee, Candice Leung | Darsan, Junior
The semi enclosed Caribbean Sea is ranked as having one of the most intense maritime traffic in the world. These maritime activities have led to significant oil pollution. Simultaneously, this sea supports many critical habitats functioning as a Large Marine Ecosystem (LME). While the impacts of oil pollution are recognised, a number of management challenges remain. This study applies spatial modelling to identify critical areas potentially at risk from oil spills in the form of a potential oil spill risk (POSR) model. The model indicates that approximately 83% of the sea could be potentially impacted by oil spills due to shipping. The results from this study collectively support a management framework for minimising ship generated oil pollution in the Caribbean Sea. Among the recommended components are a common policy, surveillance and monitoring controls, standards, monitoring programmes, data collection and greater rates of convention ratifications.
显示更多 [+] 显示较少 [-]Metabarcoding approach for nonindigenous species surveillance in marine coastal waters
2015
Zaiko, Anastasija | Samuiloviene, Aurelija | Ardura, Alba | García Vázquez, Eva
In this study, high-throughput sequencing (HTS) metabarcoding was applied for the surveillance of plankton communities within the southeastern (SE) Baltic Sea coastal zone. These results were compared with those from routine monitoring survey and morphological analyses. Four of five nonindigenous species found in the samples were identified exclusively by metabarcoding. All of them are considered as invasive in the Baltic Sea with reported impact on the ecosystem and biodiversity. This study indicates that, despite some current limitations, HTS metabarcoding can provide information on the presence of exotic species and advantageously complement conventional approaches, only requiring the same monitoring effort as before. Even in the currently immature status of HTS, this combination of HTS metabarcoding and observational records is recommended in the early detection of marine pests and delivery of the environmental status metrics of nonindigenous species.
显示更多 [+] 显示较少 [-]Screening for contaminant hotspots in the marine environment of Kuwait using ecotoxicological and chemical screening techniques
2015
Smith, A.J. | McGowan, T. | Devlin, M.J. | Massoud, M.S. | Al-Enezi, M. | Al-Zaidan, A.S. | Al-Sarawi, H.A. | Lyons, B.P.
Kuwait is a country with low rainfall and highly concentrated industrial and domestic effluents entering its coastal waters. These can be both treated and untreated. In this study we sampled a series of coastal and open-sea sites and used a variety of analyses to identify those sites requiring the most attention. We used a high throughput GC–MS screen to look for over 1000 chemicals in the samples. Estrogen and androgen screens assessed the potential to disrupt endocrine activity. An oyster embryo development screen was used to assess biological effect potential.The chemical screen identified sites which had high numbers of identified industrial and domestic chemicals. The oyster screen showed that these sites had also caused high levels of developmental abnormalities with 100% of embryos affected at some sites. The yeast screen showed that estrogenic chemicals were present in outfalls at 2–3ng/l E2 equivalent, and detectable even in some open water sites.
显示更多 [+] 显示较少 [-]Assessing trace element contamination in Fildes Peninsula (King George Island) and Ardley Island, Antarctic
2015
Amaro, Eduardo | Padeiro, Ana | Mão de Ferro, André | Mota, Ana Maria | Leppe, Marcelo | Verkulich, Sergey | Hughes, Kevin A. | Peter, H. U. (Hans-Ulrich) | Canário, João
King George Island, situated in the South Shetland Islands archipelago, is one of the most visited sites in Antarctica. This has contributed to a high density of scientific stations and shelters in the region, especially in Fildes Peninsula. In order to evaluate the natural and anthropogenic sources of trace elements (As, Cd, Cu, Zn, Pb and Hg) soil and moss samples were collected from different sites in January 2013. In general, the results revealed homogeneous concentrations (μgg−1) for each element in the majority of collected samples (As: 3.8±1.4; Cd: 0.4±0.9; Cu: 34±4; Zn: 115±13; Pb: 20±5; Hg; 0.011±0.009). However, some samples in specific areas of Fildes Bay showed the existence of local anthropogenic activities that have contributed to the enrichment of contaminants in soils and moss samples that correlated to one another (e.g. Pb: 1101μgg−1).Human presence is linked to examples of contamination and environmental perturbation, making essential the implementation of this type of study in order to understand and protect unique places in Antarctica.
显示更多 [+] 显示较少 [-]Release of heavy metals from sediment bed under wave-induced liquefaction
2015
Sun, Zhenhong | Xu, Guohui | Hao, Ting | Huang, Zhe | Fang, Hongru | Wang, Gang
Sediments in lakes and coasts can release metals into water via static diffusion and especially resuspension. The resuspension under sediment liquefaction may severely affect the concentrations of metals in water. In this study, flume experiments were carried out twice to study the release of two metal combinations (Zn and Pb; Zn and Cu), respectively. Each experiment included three phases: consolidation; non-liquefaction and liquefaction. Results showed that total Zn concentration at liquefaction phase increased by a maximum rate of 26 compared with the consolidation phase. The concentration of particulate Zn at liquefaction phase increased by a maximum rate of 8.30 compared with the non-liquefaction phase. The average concentration of dissolved Zn at the liquefaction phase increased up to 0.24 times from the consolidation phase. Total Zn concentration at the non-liquefaction phase increased by several times compared with the consolidation phase. Metals were homogeneously distributed in the liquefaction layer through wave actions.
显示更多 [+] 显示较少 [-]Effects of aquaculture fallowing on the recovery of macrofauna communities
2015
Zhulay, Irina | Reiss, Katrin | Reiss, Henning
The fallowing period is a management measure in aquaculture where the production is paused for a few months to reduce the impact on the benthic environment. We studied the effects of different fallowing periods on the recovery of macrofauna at two salmon farms in Norway. The macrofauna at the farm stations were characterised by high abundances of opportunistic taxa (e.g. Capitella spp.), low diversity and significantly different community structure compared to reference sites. The fallowing initiated macrofauna recovery at both farm stations, indicated by a decline of dominant opportunistic taxa after 2months. Significant changes in taxa composition occurred only after 6months, although indications of disturbance were still evident. Surprisingly, no corresponding spatial or temporal differences were found in the sediment parameters such as redox, TOC and pH. The results suggest that macrofauna is a more sensitive indicator and that the seasonal timing of fallowing may affect recovery dynamics.
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