Cited by 15Aquatic Ecosystems and Phytoplankton DynamicsWater Quality Monitoring TechnologiesWater Quality Monitoring and Analysis

A soft sensor for simulating algal cell density based on dynamic response to environmental changes in a eutrophic shallow lake

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Rao, Wenxin, Qian, Xin, Fan, Yifan, Liu, Tong·2023·Science of The Total Environment

Abstract

There is a great need for timely monitoring and rapid water quality assessment to control the algal blooms that often occur in eutrophic lakes. While algal cell density (ACD) is a critical indicator of algal growth, field monitoring is laborious and time-consuming, and rapid assessment of algal blooms based on ACD is often not possible. To address the limitations of conventional ACD detection, we proposed a soft sensor approach that uses surrogate indicators to simulate ACD in machine learning models. We conducted a case study using monitoring data from Chaohu Lake collected between 2016 and 2019. We found that ensemble learning models, especially extreme gradient boosting (XGBoost), outperformed traditional machine learning algorithms by comparing various machine learning algorithms. Also, considering the influence of input variable selection on model performance, we combined the results of different filter methods in the multi-stage variable selection process. Finally, we screened out seven key variables out of the 43 initial candidate variables, including dissolved oxygen (DO), chlorophyll-a (Chl-a), Secchi disk depth (SD), pH, permanganate index (COD Mn ), week of the year (WOY), and wind velocity (WV). Their inclusion substantially improved data accessibility and supported the development of a rapid simulation model. The final model was capable of reliable spatiotemporal generalization, with an overall R 2 value of 0.761. On the theoretical side, our study makes a new attempt to simulate ACD values in a eutrophic lake. For practical purposes, the soft sensor can facilitate the rapid assessment of bloom conditions, which helps the local administration with emergency prevention and control.

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Crossref · 10.1016/j.scitotenv.2023.161543

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Authors
Rao, W., Qian, X., Fan, Y., & Liu, T.
Affiliations
  • State Key Laboratory of Pollution Control and Resource Reuse (CN)
  • Nanjing University of Information Science and Technology (CN)
  • Hokkaido University (JP)
Corresponding author
Qian, Xin
Venue
Science of The Total Environment
Publisher
Elsevier BV
Published
2023-04
Volume
868
Pages
161543
ISSN
0048-9697 (ISSN-L)
OpenAlex
W4315645287
Cited by
15
References
77
Citations by year
2026: 3 · 2025: 3 · 2024: 9
FWCI
1.06
Type
journal article
Language
en
Open access
Locations
  • The Science of The Total Environment (publishedVersion)
  • SSRN Electronic Journal (publishedVersion)
  • PubMed (publishedVersion)
Funders
  • National Natural Science Foundation of China (41907388)
  • Natural Science Foundation of Jiangsu Province (BK20211155)
Topics
  • Physical Sciences › Environmental Science › Environmental Chemistry › Aquatic Ecosystems and Phytoplankton Dynamics
  • Physical Sciences › Environmental Science › Water Science and Technology › Water Quality Monitoring Technologies
  • Physical Sciences › Environmental Science › Waste Management and Disposal › Water Quality Monitoring and Analysis
Keywords
algal density, soft sensors, algal bloom monitoring, eutrophic shallow lakes, Chaohu Lake, surrogate markers, XGBoost, ensemble learning, feature selection, dissolved oxygen, chlorophyll a, Secchi depth, permanganate index, wind speed, water quality assessment
MeSH terms
Chlorophyll A, China, Environmental Monitoring, Eutrophication, Lakes, Water Quality

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