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Machine learning

DOM Optical Characteristics and Water Quality in the Bohai Sea: A Research Update

Strategic Insights

— 2 min read

Researchers from the National Marine Environmental Monitoring Center have conducted a comprehensive study on the relationship between dissolved organic matter (DOM) optical characteristics and water quality in the Bohai Sea. The study, funded by several Chinese organizations, analyzed DOM distribution and nutrient concentrations in the sea and its four basins, including 32 inflow rivers. The research found significant correlations between DOM optical indices and water quality parameters, and developed a method for predicting water quality based on these indices. The study's findings highlight the importance of DOM in monitoring and predicting water quality.

Key Takeaways:

  • The study investigated DOM distribution and nutrient concentrations in the Bohai Sea and its four basins, including 32 inflow rivers.
  • The analysis revealed relatively high total nitrogen and total phosphorus pollutant content in the Yellow River Basin and Liaohe Rivers Basin.
  • Excitation-emission matrix spectroscopy combined with parallel factor analysis (EEMs-PARFAC) identified three fluorescent components in the DOM, including two terrestrial humic-like substances (C1, C3) and one protein-like substance (C2).
  • Pearson correlation analysis revealed significant correlations between fluorescent components and optical indices, including humification index (HIX), absorption coefficient at 350 nm (a350), molecular weight (E2/E3), biological index (BIX), and fluorescence index (FI) with water quality parameters.
  • Partial least squares regression (PLSR) and support vector machine (SVM) models confirmed that a350, C1, and HIX were excellent parameters for predicting water quality, particularly NO3--N, dissolved inorganic nitrogen (DIN), TN, and TP, with fitting coefficients greater than 0.83.
  • The study provides an effective method for water quality monitoring using DOM optical indices.

Statistics:

  • The study analyzed 32 inflow rivers within the Bohai Sea.
  • The Yellow River Basin and Liaohe Rivers Basin showed relatively high total nitrogen and total phosphorus pollutant content (30.6% and 25.6%, respectively).
  • Pearson correlation analysis revealed significant correlations between fluorescent components and optical indices with water quality parameters, with coefficients ranging from 0.83 to 0.98.
  • The fitting coefficients for PLSR and SVM models were greater than 0.83 for NO3--N, DIN, TN, and TP.
  • The study identified three fluorescent components, including two terrestrial humic-like substances and one protein-like substance.

Sources:

  • Evaluation and Estimation of Water Quality Based On Eems-parafac and Optical Indices In the Bohai Rim. Journal of Environmental Chemical Engineering, 2025;13(4).
  • NewsRx. Studies from National Marine Environmental Monitoring Center Update Current Data on Robotics and Machine Learning (Evaluation and Estimation of Water Quality Based On Eems-parafac and Optical Indices In the Bohai Rim). Robotics & Machine Learning. August 4, 2025; p 4911.

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