Stratification patterns in Taconite Inlet, Ellesmere Island, N.W.T.     

Stuart D. Ludlam 《Journal of Paleolimnology》1996,16(2):205-215

The middle arm of Taconite Inlet shows many features in common with high-Arctic fjords and coastal meromictic lakes. The surface mixed layer is fresh, and a relatively constant 5.5 m deep, indicating a layer of ice of approximately the same thickness blocks communication with the Arctic Ocean. Below the primary halocline to a depth of 85 m, at least partial communication with the Arctic Ocean exists as indicated by the oxygen, salinity and thermal structures. A sill is probably found between 40 and 85 m depth, reducing circulation below it and contributing to the oxycline. For a long but undetermined period prior to the separation of lakes C1, and C2 from the middle arm of Taconite Inlet, the surface water of the inlet was probably strongly brackish to marine suggesting that the entrance to Taconite Inlet was not blocked by an ice shelf at the time of separation. The deep water of these future lakes probably became isolated from the general estuarine circulation and began to develop some of their present limnological features prior to actual separation of the surface waters of the lakes from the inlet.This is the seventh in a series papers published in this issue on the Tactonite Inlet Lakes Project. These papers were collected by Dr R. S. Bradley.  相似文献   

The comparative limnology of high arctic, coastal, meromictic lakes   总被引：3，自引：0，他引：3  

Stuart D. Ludlam 《Journal of Paleolimnology》1996,16(2):111-131

Five important features appear in rough order from the surface downwards in physical and chemical profiles from high arctic coastal meromictic lakes. These features are: (1) a supersaturated oxygen maximum, (2) the center of the oxycline, (3) a thermal maximum, (4) a major absorption maximum, and (5) an anoxic stratum. The depth of the absorption maxima and the top of the anoxic strata are both statistically correlated to light penetration and to each other. The depth of the thermal maximum also shows a statistical correlation to light penetration among lakes with a relatively shallow chemocline. The temperature of the thermal maximum appears to be maintained by inputs of light energy while the oxygen maximum is maintained to a large extent by photosynthesis. Thus, these major features are all influenced by light penetration. With the exception of the supersaturated oxygen maximum, all of the above features are dependent for their existence upon the primary chemocline stabilizing the water column. Apparently, in at least some lakes, a near surface secondary chemocline or cool (ca. 4°C) secondary inverse thermocline will enhance the stability of the water column above the primary chemocline sufficiently to allow a supersaturated oxygen maximum to develop in this region. However, the supersaturated oxygen maximum can extend into the primary chemocline, and in highly transparent Sophia Lake (Cornwallis Island, N.W.T.) this feature extends below the primary chemocline.Where the chemocline is found below depths with adequate illumination, features other than the supersaturated oxygen maximum should be found in deeper water as well, or they should be eliminated from the profiles. Thus, where the chemocline is relatively shallow, the depth of features like the thermal maximum or anoxic strata are related most closely to light penetration, but where chemoclines are deep, as in Lake Tuborg (Ellesmere Island, N.W.T.), the depth of the chemocline determines the depth of the oxycline, thermal maximum, absorption maximum and anoxic stratum.This is the second in a series of papers published in this issue on the Taconite Inlet Lakes Project. These papers were collected by Dr R. S. Bradley.  相似文献   

Agricultural Chemical News     

Stuart Cohen 《Ground Water Monitoring & Remediation》1993,13(1):87-88

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Agricultural Chemical News     

Stuart Cohen 《Ground Water Monitoring & Remediation》1993,13(3):99-102

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Rayleigh-Taylor instability: experiments with image analysis     

Stuart B. Dalziel 《Dynamics of Atmospheres and Oceans》1993,20(1-2)

Rayleigh-Taylor instability is investigated in the laboratory using a simple apparatus of novel design to set up the unstable initial conditions. Visualisation techniques give a qualitative view of the development of the instability. Quantitative measurements are obtained through digital image analysis. Of primary interest is the evolution of the velocity field. Measurements are made over a two dimensional slice of the flow using an efficient, high-resolution particle tracking technique. This technique is described and its strengths and limitations are discussed in comparison with traditional measurement techniques. The visualisations and velocity measurements are compared with the experimental and numerical results of previous workers.  相似文献   

Stick-Nest Rat Middens as Sources of Paleoecological Data in Australian Deserts     

Stuart Pearson  John R. Dodson 《Quaternary Research》1993,39(3)

The existing paleoenvironmental data from the Australian arid zone lack sensitivity and come from only a few sites. Macrofossils and pollen from four dated middens of the stick-nest rat (Leporillus spp.) were analyzed from two sites in Western Australia. Animal and plant macrofossil remains were well preserved and provided evidence of change in species distribution within the last 1150 yr. Brush-tail possum and golden bandicoot have contracted their ranges in the recent past, possibly since the introduction of cats into Australia. An undescribed lacewing was also a significant find. Pollen preserved in parts of the same midden and in middens from different sites indicates that records are sensitive to the composition of the local vegetation when the midden was built. Pollen spectra are quite different from playa lakes, which record largely regional vegetation. Pollen preserved in the fecal pellets, desiccated urine, and grass mat nesting material provided similar information but some differences were apparent, suggesting dietary preferences were reflected in the fecal component. The pollen record suggested a trend to less-wooded vegetation cover in central Australia between 900 and 300 yr B.P.  相似文献   

A Ground Water Monitoring Study for Pesticides and Nitrates Associated with Golf Courses on Cape Cod     

Stuart Z. Cohen  Susan Nickerson  Robert Maxey  Aubry Dupuy Jr.  Joseph A. Senita 《Ground Water Monitoring & Remediation》1990,10(1):160-160

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Physical processes determining the chromospheric temperature distribution     

Stuart D. Jordan 《Solar physics》1977,51(1):51-59

Calculations performed with several models of the solar chromosphere support Ulmschneider's conclusion that relatively short period acoustic waves heat the low chromosphere in the region just above the temperature minimum. However, these same short period waves (10 period P80 s) are not able to maintain chromospheric temperatures at heights where _5000Å(normal) < 10^-6. The calculations also show that an earlier conjecture stating that the H₂ population might influence the non-LTE chromospheric H^- population is probably not correct, due to lower values of the ratio n _e/n _H inferred from more recent observations. Finally, the calculations support Athay's contention that the Cayrel mechanism alone cannot produce the observed temperature rise, because the magnitude of the radiative cooling in the lines is too great.  相似文献   

A synthesis of the early life history of the anglerfish, Lophius piscatorius (Linnaeus, 1758) in northern British waters   总被引：1，自引：0，他引：1  

Hislop  John R.G.; Gallego  Alejandro; Heath  Michael R.; Kennedy  Fiona M.; Reeves  Stuart A.; Wright  Peter J. 《ICES Journal of Marine Science》2001,58(1):70-86

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The drying up of Britain? A national estimate of changes in seasonal river flows from 11 Regional Climate Model simulations     

Christel Prudhomme  Andy Young  Glenn Watts  Tracey Haxton  Sue Crooks  Jennifer Williamson  Helen Davies  Simon Dadson  Stuart Allen 《水文研究》2012,26(7):1115-1118

As climate change may modify the hydrological cycle significantly, understanding the impact on river flow is important because it affects long‐term water resources planning. Here, we describe a high‐resolution British assessment of changes in river flows in the 2050s under 11 different realisations of HadRM3. In winter, river flows may either increase or decrease, with a wide range of possible decreases in summer flow. These results should encourage adaptation that copes with a broad range of future hydrological conditions. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献