خيارات البحث
النتائج 531 - 540 من 1,546
Low altitude remote-sensing method to monitor marine and beach litter of various colors using a balloon equipped with a digital camera النص الكامل
2012
Kako, Shin’ichiro | Isobe, Atsuhiko | Magome, Shinya
This study aims to establish a low-altitude remote sensing system for surveying litter on a beach or the ocean using a remote-controlled digital camera suspended from a balloon filled with helium gas. The resultant images are processed to identify the litter using projective transformation method and color difference in the CIELUV color space. Low-altitude remote sensing experimental observations were conducted on two locations in Japan. Although the sizes of the litter and the areas covered are distorted in the original photographs taken at various angles and heights, the proposed image process system is capable of identifying object positions with a high degree of accuracy (1–3m). Furthermore, the color difference approach in the CIELUV color space used in this study is well capable of extracting pixels of litter objects of various colors allowing us to estimate the number of objects from the photographs.
اظهر المزيد [+] اقل [-]Role of living environments in the accumulation characteristics of heavy metals in fishes and crabs in the Yangtze River Estuary, China النص الكامل
2012
Zhao, Shou | Feng, Chenghong | Quan, Weimin | Chen, Xiaofeng | Niu, Junfeng | Shen, Zhenyao
Correlation of heavy metals in the tissues of typical organisms (i.e., fishes and crabs) and those in their living environments (i.e., surface water, bottom water, and sediment) in Yangtze River Estuary has been qualitatively and quantitatively analyzed. Metal levels followed the trend: sediments >Eriocheir sinensis>Eriocheir leptognathus>benthic fish>pelagic fish>bottom water>surface water. Tissues in fishes and crabs of different species and sizes had diverse metal bioaccumulation characteristics, which was significantly affected by environment factors and their living habits. Metal levels in legs of crabs, and heads and skins of fishes showed significant correlations with those in their living environments. Collichthys lucidus is an effective bioindicator for assessing metal levels in water. No significant health risk was identified by the estimated daily intake and target hazard quotients analyses.
اظهر المزيد [+] اقل [-]Asia–Pacific mussel watch for emerging pollutants: Distribution of synthetic musks and benzotriazole UV stabilizers in Asian and US coastal waters النص الكامل
2012
Nakata, Haruhiko | Shinohara, Ryu-Ichi | Nakazawa, Yusuke | Isobe, Tomohiko | Sudaryanto, Agus | Subramanian, Annamalai | Tanabe, Shinsuke | Zakaria, Mohamad Pauzi | Zheng, Gene J. | Lam, Paul K.S. | Kim, Eun-Young | Min, Byung-Yoon | We, Sung-Ug | Viet, Pham Hung | Dūc Sʹāṅ Tānā, | Prudente, Maricar | Frank, Donnell | Lauenstein, G. G. | Kannan, Kurunthachalam
We analyzed 68 green and blue mussels collected from Cambodia, China, Hong Kong, India, Indonesia, Japan, Korea, Malaysia, Philippines, Vietnam and the USA during 2003 and 2007, to elucidate the occurrence and widespread distributions of emerging pollutants, synthetic musks and benzotriazole UV stabilizers (BUVSs) in Asia–Pacific coastal waters. Synthetic musks and BUVSs were detected in mussels from all countries, suggesting their ubiquitous contamination and widespread distribution. High concentrations of musks and BUVSs were detected in mussels from Japan and Korea, where the levels were comparable or greater than those of PCBs, DDTs and PBDEs. Significant correlations were found between the concentrations of HHCB and AHTN, and also between the concentrations of UV-327 and UV-328, which suggest similar sources and compositions of these compounds in commercial and industrial products. To our knowledge, this is the first study of large-scale monitoring of synthetic musks and BUVSs in Asia–Pacific coastal waters.
اظهر المزيد [+] اقل [-]Identifying fluorescent pulp mill effluent in the Gulf of Maine and its watershed النص الكامل
2012
Cawley, Kaelin M. | Butler, Kenna D. | Aiken, George R. | Larsen, Laurel G. | Huntington, Thomas G. | McKnight, Diane M.
Using fluorescence spectroscopy and parallel factor analysis (PARAFAC) we characterized and modeled the fluorescence properties of dissolved organic matter (DOM) in samples from the Penobscot River, Androscoggin River, Penobscot Bay, and the Gulf of Maine (GoM). We analyzed excitation-emission matrices (EEMs) using an existing PARAFAC model (Cory and McKnight, 2005) and created a system-specific model with seven components (GoM PARAFAC). The GoM PARAFAC model contained six components similar to those in other PARAFAC models and one unique component with a spectrum similar to a residual found using the Cory and McKnight (2005) model. The unique component was abundant in samples from the Androscoggin River immediately downstream of a pulp mill effluent release site. The detection of a PARAFAC component associated with an anthropogenic source of DOM, such as pulp mill effluent, demonstrates the importance for rigorously analyzing PARAFAC residuals and developing system-specific models.
اظهر المزيد [+] اقل [-]Assessing confinement in coastal lagoons النص الكامل
2012
Measures of transport scale in aquatic systems can contribute to the formulation of definitions of indicators of the system’s ecological properties. This paper addresses confinement, a specific transport scale proposed by biological scientists as a parameter that can capture and synthesize the principal properties that determine the spatial structure of biological communities in transitional environments. Currently, there is no direct experimental measure of confinement. In this study, a methodology based on the accumulation rate within a lagoon of a passive tracer of marine origin is proposed, the influences of different factors in the calculation of confinement are analyzed, and general recommendations are derived. In particular, we analyze the spatial and the temporal variability of confinement and its sensitivity to the seasonal variability of climatic forcing, the inputs from rivers and the parameterization of the tidal exchanges. The Lagoon of Venice is used as a case study.
اظهر المزيد [+] اقل [-]Impact of sampling depth and plant species on local environmental conditions, microbiological parameters and bacterial composition in a mercury contaminated salt marsh النص الكامل
2012
Impact of sampling depth and plant species on local environmental conditions, microbiological parameters and bacterial composition in a mercury contaminated salt marsh النص الكامل
2012
We compare the environmental characteristics and bacterial communities associated with two rushes, Juncus maritimus and Bolboschoenus maritimus, and adjacent unvegetated habitat in a salt marsh subjected to historical mercury pollution. Mercury content was higher in vegetated than unvegetated habitat and increased with sampling depth. There was also a significant relationship between mercury concentration and bacterial composition. Habitat (Juncus, Bolboschoenus or unvegetated), sample depth, and the interaction between both, however, explained most of the variation in composition (∼70%). Variation in composition with depth was most prominent for the unvegetated habitat, followed by Juncus, but more constrained for Bolboschoenus habitat. This constraint may be indicative of a strong plant–microbe ecophysiological adaptation. Vegetated habitat contained distinct bacterial communities associated with higher potential activity of aminopeptidase, β-glucosidase and arylsulphatase and incorporation rates of ¹⁴C-glucose and ¹⁴C-acetate. Communities in unvegetated habitat were, in contrast, associated with both higher pH and proportion of sulphate reducing bacteria.
اظهر المزيد [+] اقل [-]Impact of sampling depth and plant species on local environmental conditions, microbiological parameters and bacterial composition in a mercury contaminated salt marsh النص الكامل
2012 | 1000
Cleary, D. F. R. | Oliveira, V. | Gomes, N. C. M. | Pereira, A. | Henriques, I. | Marques, B. | Almeida, A. | Cunha, A. | Correia, A. | Lillebo, A. I.
We compare the environmental characteristics and bacterial communities associated with two rushes, Juncus maritimus and Bolboschoenus maritimus , and adjacent unvegetated habitat in a salt marsh subjected to historical mercury pollution. Mercury content was higher in vegetated than unvegetated habitat and increased with sampling depth. There was also a significant relationship between mercury concentration and bacterial composition. Habitat (Juncus, Bolboschoenus or unvegetated), sample depth, and the interaction between both, however, explained most of the variation in composition (~70%). Variation in composition with depth was most prominent for the unvegetated habitat, followed by Juncus , but more constrained for Bolboschoenus habitat. This constraint may be indicative of a strong plant–microbe eco- physiological adaptation. Vegetated habitat contained distinct bacterial communities associated with higher potential activity of aminopeptidase, b -glucosidase and arylsulphatase and incorporation rates of 14C-glucose and 14C-acetate. Communities in unvegetated habitat were, in contrast, associated with both higher pH and proportion of sulphate reducing bacteria.
اظهر المزيد [+] اقل [-]Concentration of selected radionuclides in seawater from Kuwait النص الكامل
2012
Uddin, Saif | Ghadban, Abdul Nabi Al | Aba, Abdulaziz | Behbehani, Montaha
No baseline existed for the radionuclides in Kuwait territorial water. With changing trend in the region to embrace nuclear energy, the baseline study is imperative to create a reference and to record the influence-functioning of upcoming power plants. The first one in Bushehr, Iran is ready to start and several more are likely to come-up in UAE, Saudi Arabia and Kuwait. The present baseline concentration of the four considered radionuclide’s show low concentration of tritium, polonium, strontium and cesium; their concentration is comparable to most oceanic waters.
اظهر المزيد [+] اقل [-]Spatio-temporal variation of suspended and sedimentary organic matter quality in the Bay of Marseilles (NW Mediterranean) assessed by biochemical and isotopic analyses النص الكامل
2012
Cresson, Pierre | Ruitton, Sandrine | Fontaine, Marie-France | Harmelin-Vivien, M. L. (Mireille L.)
Isotopic and biochemical features of suspended particulate organic matter (POM) in the water column and of sedimentary organic matter (SOM) were investigated seasonally in the Bay of Marseilles. Biochemical compounds (carbohydrates, lipids and proteins) were consistently more concentrated in POM than in SOM, with SOM mainly composed of insoluble carbohydrates. POM displayed lower δ¹³C and higher δ¹⁵N values than SOM. Phytoplanktonic production represented the major contributor of POM year-round with spatial and seasonal variations. Climatic parameters and wind-induced currents created differences in POM contributions, with more important inputs of terrestrial OM at one sampling site. Spatial and seasonal variations were lower for SOM. The composition of this pool appeared to be linked with the permanent inputs of phytoplankton and Posidonia oceanica detritus. The combined use of biochemical and isotopic analyses was a useful tool to characterize OM pools and would help understanding the trophic functioning of this coastal environment.
اظهر المزيد [+] اقل [-]Physical and chemical control of the phytoplankton of Ahe lagoon, French Polynesia النص الكامل
2012
The environmental characteristics of Ahe deep lagoon (Tuamotu Archipelago, French Polynesia) were studied over 3years with the aim of explaining the spatial and temporal variability of the natural food available for pearl oysters with a special focus on phytoplankton biomass and global photosynthesis/respiration ratio of the lagoon. Chlorophyll averaged 0.34±0.01μgL⁻¹ and our findings did not confirm increased phytoplankton biomass in deep lagoonal waters. Phytoplankton production appears to be limited firstly by nitrogen and respiratory processes overpass photosynthetic processes at least in the north-eastern edge of the atoll. Grazing by pearl oysters in culture seems to decrease the POC concentration but not the phytoplankton biomass. Oysters graze mainly on non chlorophyllian particles.
اظهر المزيد [+] اقل [-]Is monitoring for mass spawning events in coral assemblages in north Western Australia likely to detect spawning? النص الكامل
2012
In north Western Australia coral reefs occur near ports being developed to support rapidly expanding resources industries. Dredging for port construction is required to stop during significant mass coral spawning events due to the sensitivity of gametes and larvae to increases in turbidity and sedimentation, but the timing of this event can vary between seasons and years so monitoring is used to predict when spawning is imminent. Here we used simulations to mimick sampling strategies currently used in some coral spawning monitoring programmes in Western Australia, to assess the ability of these programmes to be able to predict multi-specific mass spawning events. We found that current practices may sometimes miss spawning events that are likely to be considered large enough to warrant stopping dredging. Generally, sampling fewer individuals in a large number of species is a better way of monitoring for upcoming spawning than sampling a large number of individuals in a small number of species, but overall, greater sampling efforts than are currently undertaken are needed if moderately sized events are to be detected reliably. Determining exactly how many samples are needed, however, depends on having a clearer definition of what actually constitutes a “significant mass spawning” event in the first place.
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