摘要
在瑞典最大的三个湖泊中人们研究了影响冰河时代残余体片脚类动物Monoporeia affinis的长期(1982～2000年)种群密度的因素。在所有的三个湖泊中,Monoporeia数量都有较大的波动,在维纳恩和梅拉伦湖中还出现了明显的密度峰值。在维纳恩湖中,片脚类动物的密度显示出在一年期间内它和春季最大硅藻的生物体积有非常重要的关系。韦特恩湖中硅藻生物体积和Monoporeia密度间没有这种关系可能是由于此湖泊较深及其营养浓度比较低。在富营养的梅拉伦湖中,夏季氧不足(<4mgO_2/L)可能是一个重要的调节因素。均温层的温度显示在1989～1994年间深湖水存在一个明显的温暖周期。维纳恩和韦特恩湖均温层温度和总的太阳照射有关。然而和北大西洋波动冬天指数有关的既不是均温层水温也不是硅藻的生物体积。我们推测温度和接近湖底的氧气浓度的变化通过作用于种群的补充幼体成功率(繁殖)和幼体(年轻的)存活率来对种群密度起负面影响。
Factors affecting long-term (1982-2000) population densities of the glacial relict amphipod Monoporeia affinis were studied in Sweden's three largest lakes. Monoporeia showed large population fluctuations in all three lakes, with conspicuous peaks in density occurring in Lakes Vanem and Malaren. In Lake Vanern, amphipod densities showed highly significant relationships with spring maximum diatom biovolume at a 1-yr lag. The lack of relationship between diatom biovolumes and Monoporeia densities in L. Vattern is likely due to the larger depth and the lower nutrient content of this lake. In eutrophic L. Malaren, summer hypoxia (< 4 mg O2 L-1) is likely an important regulating factor. Hypolimnetic temperature showed a . clear periodicity with relatively warm deep water occurring between 1989 and 1994. Hypolimnetic temperatures in Vanern and Vattern were correlated with total solar irradiance. However, neither hypolimnetic water temperature nor diatom biovolumes correlated with the North Atlantic Oscillation winter index. We speculate that variations in temperature and near-bottom oxygen concentrations negatively affect population densities by acting on recruitment success (reproduction) and juvenile (young-of-the-year) survival.
