Kuwabara James S, Topping Brent R, Woods Paul F, Carter James L
U.S. Geological Survey, 345 Middlefield Road, Mail Stop 439, Menlo Park, California 94025, USA.
Environ Sci Technol. 2007 Apr 15;41(8):2811-7. doi: 10.1021/es062923l.
Coeur d'Alene Lake in northern Idaho is fed by two major rivers: the Coeur d'Alene River from the east and the St. Joe River from the south, with the Spokane River as its outlet to the north. This phosphorus-limited lake has been subjected to decades of mining (primarily for zinc and silver) and other anthropogenic inputs. A 32 full-factorial experimental design was used to examine the interactive effects of free (uncomplexed) zinc ion and dissolved-orthophosphate concentrations on phytoplankton that were isolated from two sites along a longitudinal zinc-concentration gradient in Coeur d'Alene Lake. The two sites displayed different dominanttaxa. Chlorella minutissima, a dominant species near the southern St. Joe River inlet, exhibited greater sensitivity to free Zn ions than Asterionella formosa, collected nearer the Coeur d'Alene River mouth with elevated dissolved-zinc concentrations. Empirical phytoplankton-response models were generated to describe phytoplankton growth in response to remediation strategies in the surrounding watershed. If dissolved Zn can be reduced in the water column from >500 nM (i.e., current concentrations near and down stream of the Coeur d'Alene River plume) to <3 nM (i.e., concentrations near the southern St. Joe River inlet) such that the lake is truly phosphorus limited, management of phosphorus inputs by surrounding communities will ultimately determine the limnologic state of the lake.
东部的科达伦河和南部的圣乔河，其出水口是向北的斯波坎河。这个受磷限制的湖泊已经经历了数十年的采矿活动（主要开采锌和银）以及其他人为输入。采用了32全因子实验设计，以研究游离（未络合）锌离子和溶解态正磷酸盐浓度对从科达伦湖沿纵向锌浓度梯度的两个地点分离出的浮游植物的交互作用。这两个地点显示出不同的优势类群。微小绿藻是圣乔河南部入口附近的优势物种，与在溶解锌浓度较高的科达伦河口附近采集的美丽星杆藻相比，它对游离锌离子表现出更高的敏感性。生成了经验性浮游植物响应模型，以描述浮游植物对周边流域修复策略的生长响应。如果水柱中的溶解锌能够从>500 nM（即科达伦河羽流附近及下游的当前浓度）降低到<3 nM（即圣乔河南部入口附近的浓度），从而使湖泊真正受磷限制，那么周边社区对磷输入的管理将最终决定湖泊的湖沼学状态。
