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P. A. Gillespie 《新西兰海洋与淡水研究杂志》2013,47(1):91-107
A comparative study of the heterotrophic potentials of ten New Zealand lakes was carried out. Two sampling periods were chosen, one during late August and early September 1972 (late winter, minimal thermal stratification) and another during February 1973 (mid summer, strong thermal stratification in all but two lakes). A wide range of heterotrophic potentials occurred which enabled the lakes to be placed in the following basic groups according to descending trophic levels: Group I: Rotowhero (thermal, acid lake) >Rotorua>Okaro Group II: Rotokakahi> Tikitapu >Okareka Group III: Rotoma = Rotoroa (S.I.) = Rotoiti (S.I.) = Okataina Maximum values for heterotrophic potential (Vm a x ) in micrograms of glucose per litre per hour were: Maximum heterotrophic activities were found within the metalimnion, except in Lakes Tikitapu and Rotokakahi, where maximum activities occurred within the hypolimnion. 相似文献
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Jonathan B. Thayn 《Marine Geodesy》2020,43(5):493-508
AbstractSmall stands of mangrove trees are difficult to detect and monitor using satellite remote sensing because the width of the narrow strips of vegetation are typically much smaller than the spatial resolution of the imagery. Every mangrove pixel also contains water and bare soil reflectance. Linear spectral unmixing, which estimates the fractional presence of specific land cover types per pixel, was performed on Landsat 8 imagery to detect mangroves on the eastern shoreline of the Bay of La Paz on the Baja California Peninsula of Mexico. Low-altitude aerial imagery collected from a DJI Mavic Pro drone was used as ground-reference data in the accuracy assessment. Continuous fractional presence of mangroves was detected with 80% accuracy and 85% of mangrove area was found. Future work will use linear spectral unmixing to systematically monitor mangrove extent and health in the region relative to expected growth in tourism development. 相似文献
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A. Eslami M. Alimirzaei E. Aflaki H. Molaabasi 《Marine Georesources & Geotechnology》2017,35(1):62-79
For the past four decades, the CPT has played a key role in onshore and offshore soil investigations. One of the main applications of cone penetration test (CPT) is the soil behavioral classification. Most of the developed methods for soil identification using CPT and CPTu (piezocone) data are well categorized for common soils, such as clays, silts, and sands. Soils with low resistance or more compressibility generally involve problems in geotechnical engineering practice and construction projects. Consequently, these unusual deposits require further evaluation and more detailed data. Five major groups of problematic soils including: liquefiable, sensitive, peaty, collapsible, and expansive soils have been considered in this study. One hundred and forty CPT and CPTu test records were collected from fifteen countries. Sixty-one of the records are related to difficult soils. A brief comparison is performed for currently used soil behavioral classification charts, such as by Campanella et al. (1985), Robertson (1990), Jefferies and Davies (1991) and Eslami and Fellenius (1997). Analysis based on CPT data indicates that a few commonly used charts recognize relatively well problematic deposits. However, further studies are needed to increase the accuracy and capability of methods. Existing charts have some problems due to the limitations of the nature of rectangular charts based on two axes. A new format of classification chart, i.e., triangular form containing cone tip resistance (qc), sleeve friction (fs), and pore pressure (u2) is proposed for soil identification which can be realized in practice. The proposed chart with more accuracy and less scattering of data than the previous charts is able to identify soil types particularly for deltaic soils. 相似文献