A Critical Review of Methods for Analyzing Freshwater Eutrophication

Yan Zhang,Xin Chen,Hailong Wang,Jiefeng Dong,Yanping Bao,Hui Lu,Mingxuan Li,Weicheng Xu,Zihan Zhan,Hong Yang,Lukas Van Zwieten,Xueding Jiang,Aref Alshameri

doi:10.3390/w13020225

Abstract

Water eutrophication is a global environmental problem that poses serious threats to aquatic ecosystems and human health. The evaluation of eutrophication provides a theoretical basis and technical guidance for the management and rehabilitation of water ecosystems. In the last four decades, dozens of evaluation methods have been applied to freshwater eutrophication, but there is a clear need to optimize and standardize the most suitable methods. We have addressed this gap by presenting a systematic review of methodologies. Due to the diversity and complexity of water bodies, no single evaluation method was identified that would adequately represent eutrophication under all scenarios. We demonstrate that lakes can best be assessed using the trophic level index (TLI) method, reservoirs and wetlands the trophic state index (TSI) and fuzzy comprehensive evaluation (FCE) method, respectively, and rivers the FCE method or back propagation (BP) neural network methods. More recently applied methodologies including spectral imaging and 3-D mapping of water quality using underwater gliders allow greater resolution and can be effective in managing waterbodies to avoid future eutrophication. The aim of this review is to guide future studies on the most appropriate methods available for assessing and reporting water eutrophication.

Highlights

Water eutrophication has become an increasingly serious problem worldwide [1]
Water eutrophication refers to the phenomenon whereby an excess of nitrogen (N), phosphorus (P), and other inorganic nutrients enter a relatively closed and slow-flowing water body stimulating the proliferation of algae and other plankton in the water, resulting in lower dissolved oxygen (DO), increased chlorophyll-a (Chl-a) content and the deterioration of water quality
In order to study the feasibility of the evaluation method, we set up two criteria: (1.) In order to ensure that data was not influenced by studies that assessed minor water bodies, we excluded datasets where waterbodies had an area < 1 km2

Summary

Introduction

Water eutrophication refers to the phenomenon whereby an excess of nitrogen (N), phosphorus (P), and other inorganic nutrients enter a relatively closed and slow-flowing water body (such as lake, reservoir, river and freshwater wetland) stimulating the proliferation of algae and other plankton in the water, resulting in lower dissolved oxygen (DO), increased chlorophyll-a (Chl-a) content and the deterioration of water quality. This can result in the death of fish and other aquatic life. The number of eutrophic lakes increased from 41 to 61% between the late 1970s to the late

Objectives

Methods

Conclusion