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Groundwater plays an important role in New Zealand water supplies and hence monitoring activities are conducted regularly. Most monitoring programmes aim to evaluate groundwater chemistry and almost completely overlook the microbial component in this ecosystem. In our present study, the bacterial community structure of groundwater in the Wairarapa Valley was examined using the terminal restriction fragment length polymorphism (T-RFLP), and relationships between bacterial community structure and groundwater chemistry, aquifer confinement and groundwater usage were explored. In addition, the results from this study were compared with a previous T-RFLP survey of the same area in an attempt to detect changes in bacterial community structure over time. The data obtained suggested that bacterial community structure was related to groundwater chemistry, especially to redox conditions. Species composition showed minimal variation over time if groundwater chemistry remained unchanged. These findings reflect the potential of using bacterial communities as biological indicators to evaluate the health of groundwater ecosystems. We suggest that it is important to include this type of broad bacterial diversity assessment criteria into regular groundwater monitoring activities. 相似文献
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This article deals with the morpho- and lithodynamic role of ice in shaping the Arctic coasts. Taking the Pechora Sea as an example, the direct and indirect impact of ice on the sea floor and shores is described. Active gouging by ice floes, ice-rafting of sedimentary material, formation of strudel scour depressions and frozen rocks on shallows are all direct impacts. The indirect impact of ice that arrests the coastal zone for most of the year is a considerable reduction of the overall energy of waves and currents. Based on the performed analysis, we plot a schematic zonation of the Pechora Sea according to the probable impact of ice on the shores and seafloor. 相似文献
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Considered is the drift of 10 icebergs and 18 ice fields in the northeastern part of the Barents Sea from late May to September 2009. The drift speed is estimated by GPS measurements of geographic coordinates, and the wind, using the air pressure field. The drift variability in the range of synoptic and intraseasonal variability is analyzed by the vector-algebraic method based on the model of the random Euclidean vector. The conjugacy of the drift with the wind is represented by the indices of vector regression (the theory of A.M. Obukhov) and vector correlation. Ice fields differ from icebergs by the high velocities of drift, significant variability, and higher correlation with the wind (0.85–0.99 for fields and 0.78–0.91 for icebergs). The wind and nonwind components of the drift are singled out by the Watanabe-Gudkovich correlation method. Wind coefficients and angles of deviation for the wind drift component amounted to 0.016–0.023 and ?6°…+9° for fields and 0.010–0.015 and 10°–15° for icebergs. The cyclonic circulation is developed in the area of permanent surface currents (of the nonwind nature). 相似文献
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