State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, China.
The First Institute of Oceanography, Ministry of Natural Resources, 6 Xianxialing Road, Qingdao 266061, China.
Sci Total Environ. 2022 Nov 10;846:157483. doi: 10.1016/j.scitotenv.2022.157483. Epub 2022 Jul 20.
Phosphorus is an integral component of marine biogeochemistry. This research investigated the environmental behavior of P in Laizhou Bay using high-resolution sampling, P fractionation, and isotherm adsorption. The total dissolved P (TDP) concentration ranged from 8.4 to 61.0 μg/L in the bay water, while total P (TP) concentration ranged from 311.6 to 654.5 mg/kg in the sediment. The TDP concentration in the water was high in the estuarine area of the Yellow River and the southwestern bay under the combined effects of riverine inputs, direct wastewater discharge, and limited water exchange ability. High TP concentrations in the sediment were observed near the mouth of the Yellow River and central bay, mainly due to the movement and settlement of fine suspended particles under the influence of ocean currents. The P in the bay sediment was predominantly in the calcium-bound fraction and was associated with small particles such as silt and clay. The equilibrium P concentration (EPC) ranged from 1.6 to 131.4 μg/L, and P partition coefficient or buffer intensity (K) ranged from 104 L/kg to 880 L/kg. The EPC decreased from the northeastern to southwestern area, while K showed an inverse distribution; therefore, the southwestern bay sediment had high buffer intensity for external P loads. Additionally, ECP increased linearly, and K decreased with exchangeable P (Exc-P) and Fe-bound P (Fe-P) concentrations in the sediment, demonstrating that P sediment-water exchange in LZB was dominated by contributions from Exc-P and Fe-P. These results can aid the understanding of the P sources and geochemistry of coastal ecosystems, particularly sediment P release potential.
磷是海洋生物地球化学的一个组成部分。本研究采用高分辨率采样、磷形态分析和等温吸附等方法，研究了莱州湾磷的环境行为。湾内水体总溶解磷（TDP）浓度范围为 8.4-61.0μg/L，沉积物总磷（TP）浓度范围为 311.6-654.5mg/kg。黄河口和西南湾的河口区域，由于河流输入、直接污水排放和有限的水交换能力的共同作用，湾内水体 TDP 浓度较高。黄河口附近和湾中部的沉积物 TP 浓度较高，主要是由于海流作用下细悬浮颗粒的运移和沉降。湾内沉积物中的磷主要以钙结合态为主，与细颗粒如粉砂和粘土结合。平衡磷浓度（EPC）范围为 1.6-131.4μg/L，磷分配系数或缓冲强度（K）范围为 104 L/kg-880 L/kg。EPC 从东北向西南方向逐渐降低，而 K 则呈现相反的分布；因此，西南湾的沉积物对外源磷负荷具有较高的缓冲强度。此外，EPC 与沉积物中可交换磷（Exc-P）和铁结合磷（Fe-P）浓度呈线性增加，K 呈线性降低，表明莱州湾沉积物-水之间的磷交换主要受 Exc-P 和 Fe-P 的影响。这些结果有助于了解沿海生态系统的磷来源和地球化学特性，特别是沉积物磷释放潜力。
