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Updated: Jun 23, 2026

Laboratory-determined Phosphorus Flux from Lake Sediments as a Measure of Internal Phosphorus Loading
Published on: March 6, 2014
Riverine inputs and sedimentary controls on phosphorus burial in the Bohai Sea: Implications for eutrophication
Hanbin Xu1, Menglu Li2, Jun Liu1
1Marine Bioresource and Environment Research Centre, First Institute of Oceanography, Ministry of Natural Resources, Qingdao, 266061, China.
Abstract:
Riverine inputs and sedimentary processes jointly regulate nutrient cycling in semi-enclosed coastal seas, yet their combined influence on phosphorus (P) dynamics remains insufficiently understood. This study evaluates the chemical forms, spatial gradients, burial, and long-term evolution of sedimentary P from the Yellow River Estuary Wetland to the Bohai Sea based on observations from 2011 to 2020. A pronounced regional pattern was identified, with detrital P dominating and a clear land-sea gradient reflecting the influence of major riverine inputs. Spatial heterogeneity was further expressed through contrasting sedimentary environments: high-sedimentation areas accumulated substantial detrital P, whereas regions with stronger biological activity exhibited elevated reactive P. At the sediment-water interface, burial exceeded benthic release, enhancing deposition of reactive P and contributing to a 22.7% increase in total sedimentary P from 1998 to 1999 to 2018-2020, indicative of efficient downward transport. Despite this, porewater data showed that benthic efflux remained sufficient to influence nutrient stoichiometry in the overlying water. Elevated nitrogen-to-phosphorus ratios, amplified by terrestrial loading and imbalanced benthic fluxes, reinforce persistent P limitation and highlight the vulnerability of the Bohai Sea to nutrient imbalance. These results highlight the central role of river-sea coupling in regulating coastal P pool and guiding eutrophication management.
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