An assessment of manganese and iron in Kentucky Lake using Tubifex tubifex (Oligochaeta:Tubificidae)

The sediment reworking rates of Tubifex tubifex were measured in various Kentucky Lake sediments using a 137cesium marker layer in natural sediments and in sediments with various iron and manganese levels and a gamma-scan biomonitoring system to assess the suitability of Kentucky Lake benthic habitats with respect to burrowing organisms. The gamma-scan experiment indicated that burrowing organisms cannot inhabit the sediments from the eastern side of the lake. Worm activity rates decreased as manganese concentrations were increased.. However, when iron was added to sediments at three levels (20.2, 60.0, and 100 mg/L) the worm activity rates did not correspond with increasing concentrations.

本研究采用天然沉积物中添加铯-137（137cesium）标记层的方法，结合不同铁、锰浓度梯度的沉积物样本与γ扫描生物监测系统，测定了肯塔基湖多种沉积物中苏氏尾鳃蚓（Tubifex tubifex）的沉积物扰动速率，以评估肯塔基湖底栖生境对掘穴生物的适宜性。γ扫描实验结果显示，湖东侧的沉积物无法支持掘穴生物栖息。蠕虫活动速率随锰浓度升高而降低。但当向沉积物中添加三个浓度梯度（20.2、60.0与100 mg/L）的铁时，蠕虫活动速率并未随铁浓度升高呈现规律性变化。