Impacts of Anthropogenic Disturbances on Diatom Diversity in a Shallow Spring-Fed Pool

Liang-Chi Wang,Liang-Jian Shiau,Hong-Chun Li

doi:10.3390/d14030166

Liang-Chi Wang, Liang-Jian Shiau + Show 1 more

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https://doi.org/10.3390/d14030166

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Abstract

Human impacts cause significant problems for shallow lakes in the karst regions of South China. In recent years, the ecological issues related to managing and restoring these critical aquatic ecosystems have come to the fore. Lingshui Pool (LSP) is one of the most-studied spring-fed lake ecosystems in south China, and it has well-preserved chronological profiles. The LSP was a very shallow lake before dam construction in 1962. Due to the dam’s construction, rapid development and urbanization, this important freshwater ecosystem has suffered severe eutrophication and environmental degradation. In order to determine the environmental effects of recent anthropogenic disturbances and establish conservation recommendations for this lake ecosystem, we analyzed diatoms and weak-acid leachable elements from a well-dated sediment core from LSP to reconstruct the changes in aquatic conditions and diatom diversity during the period AD 1960–2013. This revealed shifts in diatom assemblages, diversity, and geochemistry that were strongly linked to the construction of a dam in 1962 and rapid eutrophication after 1990. Diatom diversity was stable and relatively high when submerged macrophytes were present between 1962 and 1990. Thus, the reintroduction of endemic macrophytes could benefit the ecological stability and diversity of this shallow lake.

Highlights

Spring-fed lakes in karst areas are highly vulnerable freshwater ecosystems that are affected by the input of substantial amounts of materials from regional groundwater systems and local watersheds [1]
This study found that reductions in upstream discharge, increases in water consumption, and strengthening of river backflow events had caused degradation of the aquatic ecosystem that comprises Lingshui Pool (LSP) [6]
The goal of this research is to use diatom diversity records to determine the baseline conditions of aquatic ecosystem health, which could be used as a target for remediation and to identify restoration solutions for LSP

Summary

Introduction

Spring-fed lakes in karst areas are highly vulnerable freshwater ecosystems that are affected by the input of substantial amounts of materials from regional groundwater systems and local watersheds [1]. Groundwater quality is affected by land-use and landcover change, climate warming, and human activities on a regional scale [2], and it is strongly correlated with the ecosystem dynamics of lakes. The effects of human activity in the local environment, such as land development, eutrophication and pollution, are a challenge for sustainable aquatic ecosystem management, especially in densely populated areas. With increasing concerns regarding water quality, assessing the effect of dam construction on the freshwater ecosystem in a small reservoir will improve our understanding of sustainable management. This study found that reductions in upstream discharge, increases in water consumption, and strengthening of river backflow events had caused degradation of the aquatic ecosystem that comprises LSP [6]. No long-term (more than 10 years) and continuous record of the aquatic condition of the system has yet been published

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