The Belait River is a typical blackwater river in Brunei, characterized by deep tea-brown water rich in dissolved organic matter (DOM) derived from surrounding peat swamps and rainforests. This study provides a systematic assessment of the chemical composition, transformation, and transport processes of dissolved nitrogen (N) in the Belait River during alternating wet and dry seasons by integrating nitrate (NO3−) stable isotope techniques with microbial analyses. Results indicate that dissolved organic nitrogen (DON) constitutes the primary component of total dissolved nitrogen (TDN), with its seasonal dynamics significantly controlled by hydrological climate and microbial activity. Along the salinity gradient, DON decreases due to dilution and degradation, while ammonium (NH4+) and NO3− accumulate significantly in densely populated areas owing to anthropogenic inputs. The extremely low dissolved inorganic phosphorus (DIP) concentrations in the Belait River highlight the crucial role of P limitation in maintaining the system's oligotrophic state. Through the investigation in this representative blackwater system, this study highlights complex N cycling mechanisms in blackwater and provides a critical gauge in land-ocean material fluxes at the Indo-Pacific Convergence Area.
Lai L., Müller M., Sukri R.S., Wong C., Mujahid A., Liu S., Xu Z., Rixen T., Warneke T., Notholt J. and Jiang S. (2025) Dissolved nitrogen in a tropical river-sea continuum: a seasonal view on the distribution and transformation. Deep Sea Research Part II Topical Studies in Oceanography 225: 105583. 10.1016/j.dsr2.2025.105583
@article{Lai2025,
Title = {Dissolved nitrogen in a tropical river-sea continuum: a seasonal view on the distribution and transformation},
Author = {Lai, Longyun and Müller, Moritz and Sukri, Rahayu Sukmaria and Wong, Changi and Mujahid, Aazani and Liu, Sumei and Xu, Zhaomeng and Rixen, Tim and Warneke, Thorsten and Notholt, Justus and Jiang, Shan},
Editor = {},
Journal = {Deep Sea Research Part II Topical Studies in Oceanography},
Year = {2025},
Pages = {105583},
Volume = {225},
Doi = {10.1016/j.dsr2.2025.105583},
Abstract = {The Belait River is a typical blackwater river in Brunei, characterized by deep tea-brown water rich in dissolved organic matter (DOM) derived from surrounding peat swamps and rainforests. This study provides a systematic assessment of the chemical composition, transformation, and transport processes of dissolved nitrogen (N) in the Belait River during alternating wet and dry seasons by integrating nitrate (NO3−) stable isotope techniques with microbial analyses. Results indicate that dissolved organic nitrogen (DON) constitutes the primary component of total dissolved nitrogen (TDN), with its seasonal dynamics significantly controlled by hydrological climate and microbial activity. Along the salinity gradient, DON decreases due to dilution and degradation, while ammonium (NH4+) and NO3− accumulate significantly in densely populated areas owing to anthropogenic inputs. The extremely low dissolved inorganic phosphorus (DIP) concentrations in the Belait River highlight the crucial role of P limitation in maintaining the system's oligotrophic state. Through the investigation in this representative blackwater system, this study highlights complex N cycling mechanisms in blackwater and provides a critical gauge in land-ocean material fluxes at the Indo-Pacific Convergence Area.},
}
TY - JOUR
AU - Lai, Longyun
AU - Müller, Moritz
AU - Sukri, Rahayu Sukmaria
AU - Wong, Changi
AU - Mujahid, Aazani
AU - Liu, Sumei
AU - Xu, Zhaomeng
AU - Rixen, Tim
AU - Warneke, Thorsten
AU - Notholt, Justus
AU - Jiang, Shan
TI - Dissolved nitrogen in a tropical river-sea continuum: a seasonal view on the distribution and transformation
T2 - Deep Sea Research Part II Topical Studies in Oceanography
PY - 2025
SP - 105583
VL - 225
DO - 10.1016/j.dsr2.2025.105583
AB - The Belait River is a typical blackwater river in Brunei, characterized by deep tea-brown water rich in dissolved organic matter (DOM) derived from surrounding peat swamps and rainforests. This study provides a systematic assessment of the chemical composition, transformation, and transport processes of dissolved nitrogen (N) in the Belait River during alternating wet and dry seasons by integrating nitrate (NO3−) stable isotope techniques with microbial analyses. Results indicate that dissolved organic nitrogen (DON) constitutes the primary component of total dissolved nitrogen (TDN), with its seasonal dynamics significantly controlled by hydrological climate and microbial activity. Along the salinity gradient, DON decreases due to dilution and degradation, while ammonium (NH4+) and NO3− accumulate significantly in densely populated areas owing to anthropogenic inputs. The extremely low dissolved inorganic phosphorus (DIP) concentrations in the Belait River highlight the crucial role of P limitation in maintaining the system's oligotrophic state. Through the investigation in this representative blackwater system, this study highlights complex N cycling mechanisms in blackwater and provides a critical gauge in land-ocean material fluxes at the Indo-Pacific Convergence Area.
ER -
