大亚湾颗粒态氮磷的时空分布、关键影响因素及潜在生态意义

颗粒态营养盐是海洋营养盐的重要组成部分。本文通过2015年8月（夏）、12月（冬），2016年3月（春）、10月（秋）4个季节的采样分析，探讨了大亚湾海域颗粒态氮（PN）、颗粒态磷（PP）的组成分布及其关键控制因素。结果表明，大亚湾水体中PN、PP含量范围分别为2.63~26.24 μmol/L、0.11~3.71 μmol/L，平均含量分别为8.20±4.75 μmol/L、0.39±0.37 μmol/L。PN以颗粒有机氮（PON）为主，占65.0%；PP则以颗粒无机磷（PIP）为主，占63.4%。PN和PP分别约占总氮（TN）、总磷（TP）的24.8%和37.0%。大亚湾PN、PP呈现湾顶至湾口浓度下降的趋势，仅冬季部分形态分布趋势较不明显。二者的含量和分布主要受浮游植物生长与径流输入影响。此外，大亚湾PIN/PIP年均值为13.2±11.1，接近16的Redfield比值，无明显失衡现象，而湾内DIN/DIP年均值高达49.1±39.7，远大于16，说明颗粒态营养盐在维持大亚湾水体中营养盐比例平衡中起到了重要缓冲作用。

Distribution,key controlling factors and potential ecological role of particulate nitrogen and phosphorus in Daya bay

Particulate nutrients have been proved to be the important components of nutrients in seawater.In this study, particulate nitrogen (PN) and particulate phosphorus (PP) were measured in four different seasons to investigate the seasonal distribution patterns and their potential ecological roles in Daya bay.The results showed that the concentrations of PN and PP ranged from 2.63 to 26.24 μmol/L (averaged 8.20 μmol/L) and 0.11 to 3.71 μmol/L (averaged 0.39 μmol/L), respectively.The main component of PN was particulate organic nitrogen (PON), accounting for 65.0%; while PP was made up by 63.4% particulate inorganic phosphate (PIP).Meanwhile, PN and PP accounted for 24.8% and 37.0% of total phosphorus (TP) and total nitrogen (TN), respectively.PN and PP showed a decreasing trend from the inner bay to the outer bay except in winter.Runoff input and phytoplankton were considered to be the main factors controlling the spatial distribution as well as contents of particulate nutrients.In addition, the average PIN/PIP value in Daya bay was 13.2±11.1, which was close to the Redfield ratio (16:1).However, average DIN/DIP ratio (49.1±39.7) was much higher than 16:1.These combined results suggested that particulate nutrients probably played an important role in buffering and regulating nutrient structure in Daya bay.