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  • 1
    Electronic Resource
    Electronic Resource
    Sedimentation rates in Fayetteville Green Lake, New York, U.S.A. (1981)
    Oxford, UK : Blackwell Publishing Ltd
    Sedimentology 28 (1981), S. 0 
    Details
    ISSN: 1365-3091
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geosciences
    Notes: In Fayetteville Green Lake, past sedimentation rates can be accurately and precisely estimated by separating annual couplets or varves in dried sediment samples. Two measures were used, which serve as upper and lower limits on estimated sedimentation rate. They agree within 5 % with average annual sedimentation rate in couplets for recent years. Between 3 and 5 replicate samples are needed to reduce the half-width of 95 % confidence intervals on individual couplet sedimentation rates to 30 g m−2 yr−1 about 5 % of average recent rates. In the late 1800s sedimentation rate averaged 392 g m−2 yr−1 and ranged between 324 and 466 g m−2 yr−1, while in the 1970s the rate averaged 581 g m−2 yr−1 by the same measure, and ranged between 384 and 646 g m−2 yr−1. Sedimentation rate averaged for 13 years does not vary over short distances in the profundal zone, but lateral variation in sedimentation rate can be detected for individual years over the same distance. Not all this variation was associated with the non-uniform distribution of dark sublaminae and thin turbidites which cannot be separated from the annual layers. This indicates that although precise estimates of sedimentation rates can be made at different points in the lake, estimates will have to be made at numerous points before annual sedimentation rates for the lake as a whole can be accurately assessed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-3091.1981.tb01665.x
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  • 2
    Electronic Resource
    Electronic Resource
    Stratification patterns in Taconite Inlet, Ellesmere Island, N.W.T. (1996)
    Springer
    Journal of paleolimnology 16 (1996), S. 205-215 
    Details
    ISSN: 1573-0417
    Keywords: fjords ; stratification ; meromixis ; paleolimnology ; Arctic ; Ellesmere Island
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences
    Notes: Abstract 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.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00176936
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  • 3
    Electronic Resource
    Electronic Resource
    The comparative limnology of high arctic, coastal, meromictic lakes (1996)
    Springer
    Journal of paleolimnology 16 (1996), S. 111-131 
    Details
    ISSN: 1573-0417
    Keywords: meromictic lakes ; stratification ; limnology ; arctic ; Ellesmere Island
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences
    Notes: Abstract 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.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00176931
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  • 4
    Electronic Resource
    Electronic Resource
    Changes in the importance of lotic and littoral diatoms in a high arctic lake over the last 191 years (1996)
    Springer
    Journal of paleolimnology 16 (1996), S. 187-204 
    Details
    ISSN: 1573-0417
    Keywords: diatoms ; lotic diatoms ; varves ; paleolimnology ; turbidities ; high arctic
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences
    Notes: Abstract Both habitat preferences and community associations for some of the most prominent pennate taxa in our profile were established using samples from the modern lake and its watershed. Habitat preferences were used to establish a simple indicator for the relative contribution of lotic communities in this lake (Lotic Index) and indicator taxa for both littoral (Achnanthes spp. and Cymbella spp.) and lotic (Hannaea arcus and Meridion circulare) communities. When profiled, the Lotic Index showed a clear positive relationship to sedimentation rate as recorded in the varves, while profiles of littoral indicator taxa show the opposite trends. It seems likely that the patterns we observed in the Lotic Index are related to changes in runoff. Apparently, there was a period of declining runoff beginning ca. two centuries ago and ending in the late 1800's. This was followed by increasing runoff lasting until the middle of the 20th century. A brief minimum occurred in ca. 1970 followed by a recovery by ca. 1980. A strong positive relationship was also found between the dates of major turbidites, exceptionally thick varves and the concentration of valves in the sediment. It is possible that many of the thicker varves in the profiles contain littoral material transported to the site of deposition by turbid interflows and underflows. For this reason, the concentration of valves in the sediment in our cores appears to be a proxy for sediment deposition from turbidity currents.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00176935
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