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1.
A statistical quality control approachto detect changes in groundwater quality from aregulated waste unit is described. The approachapplies the combined Shewhart-CUSUM control chartmethodology for intrawell comparison of analyteconcentrations over time and does not require anupgradient well. A case study from the U.S.Department of Energy's Hanford Site is used forillustration purposes. This method is broadlyapplicable in groundwater monitoring programs wherethere is no clearly defined upgradient location, thegroundwater flow rate is exceptionally slow, or wherea high degree of spatial variability exists inparameter concentrations. This study also indicatesthat the use of the Data Quality Objectives (DQO)process can assist in designing an efficient andcost-effective groundwater monitoring plan to achievethe optimum goal of both low false positive and lowfalse negative rates (high power).  相似文献   
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Changes in the fringing coral reef community of a small island (Ko Nok) at Pattaya Bay, Gulf of Thailand, were examined at the beginning and at the end of a 3-year period using 7m×7m permanent quadrats for benthic organisms, and visual census along 100m transects for fish. The coral community was dominated by Porites lutea in terms of colony number and areal cover throughout the period. Variations in the community structure parameters on opposite sides of the island indicated increasing dissimilarity with time. Little variation in live coral cover was noted, but colony number and species diversity declined on both sides. The abundance of edible fish species dropped while that of non-edible species increased over the 3-year period, indicating selective removal of the former category through fishing. Impacts from both human and natural influences are implicated in these changes.  相似文献   
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Environmental Science and Pollution Research - There is a delayed (lag 1 to 2 days) correlation between acute PM 2.5 (particulate matter <?2.5 μm in aerodynamic...  相似文献   
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This paper offers the first study of diurnal variations in the use of an estuarine habitat by Indo-Pacific humpback dolphins. Passive acoustic data loggers were deployed in the Xin Huwei River Estuary, Western Taiwan, from July 2009 to December 2010, to collect biosonar clicks. Acoustic encounter rates of humpback dolphins on the riverside of the estuary changed significantly over the four tidal phases, instead of the two diurnal phases based on the recordings from 268 days. Among the tidal phases, the encounter rates were lowest during ebb tides. Additionally, circling movements associated with the hunt for epipelagic fish significantly changed in temporal and spatial presence over the four tidal phases, matching the overall pattern of encounter rate changes in the focal estuary. Our findings suggest that the occurrence pattern and habitat utilization of humpback dolphins are likely to be influenced by the tidal-driven activity of their epipelagic prey.  相似文献   
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For this study, field measurements of current profiles, buoy trajectories and the lag of two tidal stations were performed to explore the flow characteristics of Taichung Harbour. in order to distinguish the effects of wind drift current on circulation inside Taichung Harbour, field surveys during both summer and monsoon (winter) season were completed separately. the speed of the drift current was about 3.5% that of the, wind speed, based on the field data. the horizontal dispersion coefficients were close to Bowden's (1965) formula for the tidal current. the water temperature showed a two-layer profile, with the mixing thickness about 4 to 6 metres for the upper layer. the corresponding Richardson number was about 70. the tidal lag between the two tidal stations was 9.68 minutes. All the results agree well with the theoretical results.  相似文献   
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The phylogenetic structure of the anemonefish Amphiprion ocellaris was established based on sequence data generated for the 5′ end of the cytochrome b (cytb) gene at 11 sites throughout Southeast Asia. Considerable genetic structuring was observed throughout the range of A. ocellaris. The region has a complex geography, with the Sunda shelf having been exposed during the lower sea levels associated with periods of glaciation. The direction of subsequent flooding of the Sunda shelf, as a direct consequence of the retreating glacial sheets, can be predicted based on the major river drainage systems in the region. Much of the phylogeographic structure, including levels of intra-site genetic variation, can be explained in terms of the “seeding” of sites on the Sunda shelf, by those on the shelf rim, as sea levels rose. We often found surface ocean currents in the region, which should influence larval dispersal, to be poorly correlated with phylogeographic structure. Several geographically close sites, which appear to be connected by surface currents, showed significant genetic stratification. We hypothesise that the phylogeographic structure of A. ocellaris is more reminiscent of the Pleistocene sea level changes than surface currents. The high contribution of sea level changes to the phylogeographic structure was also supported by several missing haplotypes in the generated spanning network. Cytb DNA sequences generated for recently recruited A. ocellaris individuals sampled from Singapore indicate that, on a local scale, there is a directional inflow of recruits, which is dependent on the monsoon seasons. The nature of dispersal and genetic structure of reef fish species found on the Sunda shelf is clearly complex, and should take into consideration past phylogeographic events. Received: 13 November 1999 / Accepted: 12 July 2000  相似文献   
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The growth of symbiotic algal cells (zooxanthellae) isolated from the coral, Montipora verrucosa under the influence of the heavy metals copper (Cu) and Zinc (Zn) was investigated. Zooxanthellae cells cultured in f/2 enriched seawater medium were subjected to a maximum Cu level of 42µg.l-1, Zn concentration of 509µg.l-1, and various combinations of the two metals, in ecotoxicological bioassays lasting up to 28 days. A Cu level of 40µg.l-1 caused significantly depressed specific growth rates of cell cultures obtained using a standard growth model. Low concentrations of the metals Cu and Zn in combination elicited synergistic effects of sublethal toxicity. The use of cultured zooxanthellae cells in bioassays investigating sublethal effects of heavy metal stress has relevant applications in the field of pollution monitoring.  相似文献   
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