Using machine learning to reveal seasonal nutrient dynamics and their impact on chlorophyll-a levels in lake ecosystems: A focus on nitrogen and phosphorus

Chlorophyll-a (Chl-a) is a pivotal indicator of lake eutrophication. Studies examining nutrients limiting lake eutrophication at large scales have traditionally focused on summer and autumn, potentially limiting the applicability of their findings. This study encompasses 86 state-controlled points i...

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Main Authors: Yong Fang, Ruting Huang, Xianyang Shi
Format: Article
Language:English
Published: Elsevier 2024-12-01
Series:Ecological Indicators
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Online Access:http://www.sciencedirect.com/science/article/pii/S1470160X24013736
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author Yong Fang
Ruting Huang
Xianyang Shi
author_facet Yong Fang
Ruting Huang
Xianyang Shi
author_sort Yong Fang
collection DOAJ
description Chlorophyll-a (Chl-a) is a pivotal indicator of lake eutrophication. Studies examining nutrients limiting lake eutrophication at large scales have traditionally focused on summer and autumn, potentially limiting the applicability of their findings. This study encompasses 86 state-controlled points in the Eastern China Basin, spanning data collected from January 2020 to July 2023. Furthermore, we focus on the application of three machine-learning models (i.e., eXtreme Gradient Boosting, Support Vector Machines, and Naive Bayes Classifier) to analyze the seasonal nutrient dynamics in lake ecosystems. We categorized the monitoring data by season to eliminate outliers and employed adaptive synthetic sampling to address data imbalance issues. The results reveal that the direct correlations between total nitrogen (TN), total phosphorus (TP), and TP in conjunction with turbidity and Chl-a are broadly weak, possibly because of geographic variations, nutrient lag effects on algae, and differences in algal community composition. However, probabilistic analyses revealed that as TP or TN levels transitioned from oligo-mesotrophic (O) to eutrophic (E), TP exhibited a greater influence on the variation in Chl-a status than TN during spring and winter (p < 0.05). Conversely, the effects of TP and TN on Chl-a (O-E) were comparable during summer and autumn. Seasonal variations in TN and TP thresholds derived from XGBoost modeling for O and E states of Chl-a suggest the need for stricter control measures during periods of high-nutrient levels and cost-effective management strategies to employ during low-nutrient periods. These findings should enhance our understanding of trophic shifts in lakes and provide a foundation for optimizing eutrophication management strategies across all seasons.
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spelling doaj-art-e6569ee1f45248d4ae64e4b7917de6d92025-08-20T02:49:02ZengElsevierEcological Indicators1470-160X2024-12-0116911291610.1016/j.ecolind.2024.112916Using machine learning to reveal seasonal nutrient dynamics and their impact on chlorophyll-a levels in lake ecosystems: A focus on nitrogen and phosphorusYong Fang0Ruting Huang1Xianyang Shi2Anhui Province Key Laboratory of Wetland Ecosystem Protection and Restoration, School of Resources and Environmental Engineering, Anhui University, Hefei 230601, ChinaCorresponding authors.; Anhui Province Key Laboratory of Wetland Ecosystem Protection and Restoration, School of Resources and Environmental Engineering, Anhui University, Hefei 230601, ChinaCorresponding authors.; Anhui Province Key Laboratory of Wetland Ecosystem Protection and Restoration, School of Resources and Environmental Engineering, Anhui University, Hefei 230601, ChinaChlorophyll-a (Chl-a) is a pivotal indicator of lake eutrophication. Studies examining nutrients limiting lake eutrophication at large scales have traditionally focused on summer and autumn, potentially limiting the applicability of their findings. This study encompasses 86 state-controlled points in the Eastern China Basin, spanning data collected from January 2020 to July 2023. Furthermore, we focus on the application of three machine-learning models (i.e., eXtreme Gradient Boosting, Support Vector Machines, and Naive Bayes Classifier) to analyze the seasonal nutrient dynamics in lake ecosystems. We categorized the monitoring data by season to eliminate outliers and employed adaptive synthetic sampling to address data imbalance issues. The results reveal that the direct correlations between total nitrogen (TN), total phosphorus (TP), and TP in conjunction with turbidity and Chl-a are broadly weak, possibly because of geographic variations, nutrient lag effects on algae, and differences in algal community composition. However, probabilistic analyses revealed that as TP or TN levels transitioned from oligo-mesotrophic (O) to eutrophic (E), TP exhibited a greater influence on the variation in Chl-a status than TN during spring and winter (p < 0.05). Conversely, the effects of TP and TN on Chl-a (O-E) were comparable during summer and autumn. Seasonal variations in TN and TP thresholds derived from XGBoost modeling for O and E states of Chl-a suggest the need for stricter control measures during periods of high-nutrient levels and cost-effective management strategies to employ during low-nutrient periods. These findings should enhance our understanding of trophic shifts in lakes and provide a foundation for optimizing eutrophication management strategies across all seasons.http://www.sciencedirect.com/science/article/pii/S1470160X24013736EutrophicationNutrientsMachine learningData synthesisSeasons
spellingShingle Yong Fang
Ruting Huang
Xianyang Shi
Using machine learning to reveal seasonal nutrient dynamics and their impact on chlorophyll-a levels in lake ecosystems: A focus on nitrogen and phosphorus
Ecological Indicators
Eutrophication
Nutrients
Machine learning
Data synthesis
Seasons
title Using machine learning to reveal seasonal nutrient dynamics and their impact on chlorophyll-a levels in lake ecosystems: A focus on nitrogen and phosphorus
title_full Using machine learning to reveal seasonal nutrient dynamics and their impact on chlorophyll-a levels in lake ecosystems: A focus on nitrogen and phosphorus
title_fullStr Using machine learning to reveal seasonal nutrient dynamics and their impact on chlorophyll-a levels in lake ecosystems: A focus on nitrogen and phosphorus
title_full_unstemmed Using machine learning to reveal seasonal nutrient dynamics and their impact on chlorophyll-a levels in lake ecosystems: A focus on nitrogen and phosphorus
title_short Using machine learning to reveal seasonal nutrient dynamics and their impact on chlorophyll-a levels in lake ecosystems: A focus on nitrogen and phosphorus
title_sort using machine learning to reveal seasonal nutrient dynamics and their impact on chlorophyll a levels in lake ecosystems a focus on nitrogen and phosphorus
topic Eutrophication
Nutrients
Machine learning
Data synthesis
Seasons
url http://www.sciencedirect.com/science/article/pii/S1470160X24013736
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AT xianyangshi usingmachinelearningtorevealseasonalnutrientdynamicsandtheirimpactonchlorophyllalevelsinlakeecosystemsafocusonnitrogenandphosphorus