文章基本信息

标题：A Re-evaluation of the Trophic State of Mountain Lake, Virginia, USA
本地全文：下载
作者：Jon C. Cawley ; Bruce C. Parker ; Myron H. Beaty 等
期刊名称：Journal of Freshwater Ecology
印刷版ISSN：0270-5060
电子版ISSN：2156-6941
出版年度：1999
卷号：14
期号：4
页码：535-544
DOI：10.1080/02705060.1999.9663711
出版社：Taylor & Francis
摘要：Limnological studies of Mountain Lake, Giles County, Virginia were conducted from June to October of 1997 and April to October of 1998 to evaluate the lake's trophic state, which was considered to be in an early stage of eutrophication from the late 1980s to early 1990s. Orthophosphate-P levels averaged 1.5μg/L in 1997 and 2.2μg/L in 1998, a return from 27.0μg/L in 1990 to early and mid 1980s levels. Ammonium-N also dropped, but nitrate-N increased in 1997-98 compared to 1990. The N:P ratio of 143:1 in 1997 and 244:1 in 1998 compared to 9.4:1 in 1990 clearly indicated P as the major limiting nutrient. Dissolved silica, hardness, alkalinity, and pH in the lake were similar to earlier studies. Phytoplankton taxa and cell densities were similar to those of the mid-1980s. Mountain Lake is thus oligotrophic and presently shows no signs of eutrophication. Input streams feeding the lake were also low in key nutrients, but precipitation constituted a major source of P, N, and acidity to the lake.