the periods of peak zooplankton abundance，that is，in thelate spring and in the summer，Haney recorded maximum daily com-munitygrazing rates，for nutrient-poor lakes and bog lakes，respectively，of 6.6percent and 114 percent of daily phytoplankton production.
在浮游動物數量激增的高峯期，亦即在春季後期以及夏季，哈尼記錄了最大程度上的每日羣落食草比率，對於營養物不充足的'湖和沼澤湖而言，分別爲每日浮游植物繁殖量的6.6%和114%.
hydrologic cycle，a major topic in this science，is thecomplete cycle of phenomena through which water passes，beginning asatmospheric water vapor，passing into liquid and solid form asprecipitation，thence along and into the ground surface，and finallyagain returning to the form of atmospheric water vapor by means ofevaporation and transpiration.
水文循環，作爲該學科中的一個主要課題，指的是水所經過的諸現象的整個循環過程，開始時是作爲大氣中的水蒸氣，轉而作爲雨、雪、露、雹一類的降水量經過液體和固體形態，由此而沿着地層表面分佈或進入地層表面，最終通過蒸發和散發作用再度回覆到大氣水蒸氣的形態。
historian Frederick J. Turner wrote in the 1890s that theagrarian discontent that had been developing steadily in the UnitedStates since about 1870 had been precipitated by the closing of theinternal frontierthat is，the depletion of available new land neededfor further expansion of the American farming system.