为了解三沙湾大黄鱼（）网箱养殖衍生有机物（AOM）的沉降特征，采用原位实验方法，收集区域内使用颗粒饲料和冰鲜饵料两种典型饲喂方式下距离网箱200 m范围内AOM样品，分析其沉降量、营养物质[颗粒有机物（POM）、颗粒有机碳（POC）、颗粒态氮（PN）、总磷（TP）]沉降通量和扩散特点。研究结果表明，饲喂颗粒饲料状态下AOM沉降量显著高于投喂冰鲜饵料，两者均值分别为（563.66±119.18）g/（m²·d）和（266.07±139.15）g/（m²·d）。POM、POC、PN和TP沉降通量在两种饲喂方式下的差异与之相似，饲喂颗粒饲料时各参数均值分别为（27.25±2.43）g/（m²·d）、（6.03±0.58）g/（m²·d）、（0.66±0.06）g/（m²·d）和（0.39±0.04）g/（m²·d）；饲喂冰鲜饵料时各参数均值分别为（13.04±1.62）g/（m²·d），（3.57±0.45）g/（m²·d）、（0.51±0.06）g/（m²·d）和（0.22±0.04）g/（m²·d）。沿近底层海流主导流向距离养殖网箱100 m的空间范围内，AOM沉降量和营养物质沉降通量均呈现自网箱处递减的变化特征，下降程度在饲喂冰鲜饵料时尤为显著。AOM中POC、PN和TP含量在饲喂冰鲜饵料时较高，在距离养殖网箱50 m范围内呈现递减趋势。综上，在三沙湾大黄鱼网箱养殖过程中，投喂颗粒饲料引发的环境污染程度高于冰鲜饵料，两种情形下的AOM沉降影响主要限于距离养殖网箱50~100 m的空间范围。三沙湾内饲喂颗粒饲料引发较高营养物质沉降通量源于较大的AOM沉降量，此现象说明养殖过程中可能存在颗粒饲料过度投喂、饵料利用效率较低等问题，围绕此类问题的针对性研究对于减缓区域内养殖活动的环境影响具有重要意义。

To clarify the sedimentation characteristics of aquaculture-derived organic matter (AOM) from a large yellow croaker () cage farm in Sansha Bay, AOM samples in a sampling gradient (0-200 m away from the culture cage) were collected with sedimentation traps under two typical feeding conditions (commercial feed and raw fish). These samples were used to analyze sedimentation rate, particle organic matter (POM:particulate organic matter; POC:particulate organic carbon; PN:particulate nitrogen; TP:total phosphorus) fluxes, and their spatial expansion in this study. The sedimentation rate of AOM was (563.66±119.18) g/(m²·d) when commercial pellets were used as feed, which was significantly higher than that when raw fish was used. Particulate organic matter (POM), POC, PN, and TP fluxes were much higher when using commercial feed than raw fish, at (27.25±2.43) g/(m²·d), (6.03±0.58) g/(m²·d), (0.66±0.06) g/(m²·d), and (0.39±0.04) g/(m²·d) in the former experimental condition, and at (13.04±1.62) g/(m²·d), (3.57±0.45) g/(m²·d), (0.51±0.06) g/(m²·d), and (0.22± 0.04) g/(m²·d) in the latter situation, respectively. Particle organic matter fluxes and AOM sedimentation rates showed decreasing tendencies from 0-100 m away from the fish cage, with a particularly strong decline in the raw fish treatment. The percentage of particle organic matter in AOM also exhibited spatial variability, declining in the region from the fish cages to 50 m downstream. In summary, the environmental effects of a cage farm in Sansha Bay were much remarked when commercial pellets were used as feed. Environmental impacts derived from using both commercial pellets and raw fish were restricted to an area 50-100 m away from fish cages. The occurrence of conspicuous environmental impacts due to using commercial feeds was associated with a greater AOM sedimentation rate, and thus, studies on restricted feeding and on the efficiency of fish feed are essential to alleviate the negative impacts of aquaculture in the area.

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国家自然科学基金面上项目（41576167）；国家自然科学基金青年科学基金项目（41606139）；中央级公益性科研院所基本科研业务费项目（2013M07，2019T10）.