TY - JOUR
T1 - Dissolved nitrogen in a tropical river-sea continuum
T2 - a seasonal view on the distribution and transformation
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
N1 - Publisher Copyright:
© 2025
PY - 2026/2
Y1 - 2026/2
N2 - 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.
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.
KW - Brunei
KW - Nitrogen
KW - Seasonal changes
KW - Stable isotopes
KW - Tropical blackwater river
UR - https://www.scopus.com/pages/publications/105024492324
U2 - 10.1016/j.dsr2.2025.105583
DO - 10.1016/j.dsr2.2025.105583
M3 - 文章
AN - SCOPUS:105024492324
SN - 0967-0645
VL - 225
JO - Deep-Sea Research Part II: Topical Studies in Oceanography
JF - Deep-Sea Research Part II: Topical Studies in Oceanography
M1 - 105583
ER -
