An unpolluted regulated stream and its recovery gradient dependency from environmental variables

Author:

Doychev Dimitar D.ORCID,Taneva Lidiya R.ORCID

Abstract

Periods of thermal stratification in deep dams can result in increased liberation of ammonia and phosphates at the sediment-water interface, which can cause nutrient enrichment in the downstream river section. We studied the recovery gradient of a thermally altered, regulated, unpolluted stream and its dependency on the main environmental variables. Macroinvertebrate assemblages were assessed in the spring-summer and autumn periods, at three sampling sites in a 1.25 km river reach, downstream from the dam, for 4 years (2019-2022). Water samples were collected from all riverine sites and one site in the dam. Nutrients were measured and hydrological alteration indices were calculated for the longitudinal gradient survey. We aimed to unravel the main environmental variables linked to the dam-induced hydro-morphological pressure affecting macroinvertebrate communities. Complex interactions between nutrients and the main physical parameters were identified as responsible for the observed trends. The analysis revealed natural-born hypolimnetic ammonia as the most contributing parameter to the biomonitoring metrics reflecting the status of macroinvertebrates. Ammonia enters the river system mainly during the dam thermal stratification periods (spring-summer) and as a result, macroinvertebrate communities had the highest recovery rates in the autumn. In this season the stream can achieve good ecological status even as near as 25 m below the dam wall if ammonia concentrations are low. Therefore, seasonal fluctuations of parameters such as dissolved oxygen and temperature in the hypolimnion are affecting invertebrate communities.

Publisher

Asociacion Iberica de Limnologia

同舟云学术

1.学者识别学者识别

2.学术分析学术分析

3.人才评估人才评估

"同舟云学术"是以全球学者为主线,采集、加工和组织学术论文而形成的新型学术文献查询和分析系统,可以对全球学者进行文献检索和人才价值评估。用户可以通过关注某些学科领域的顶尖人物而持续追踪该领域的学科进展和研究前沿。经过近期的数据扩容,当前同舟云学术共收录了国内外主流学术期刊6万余种,收集的期刊论文及会议论文总量共计约1.5亿篇,并以每天添加12000余篇中外论文的速度递增。我们也可以为用户提供个性化、定制化的学者数据。欢迎来电咨询!咨询电话:010-8811{复制后删除}0370

www.globalauthorid.com

TOP

Copyright © 2019-2024 北京同舟云网络信息技术有限公司
京公网安备11010802033243号  京ICP备18003416号-3