【摘要】 根据2006年夏、冬季以及2007年春、秋季"海监49号"科学考察船的调查数据,分析了长江口跨越锋面区域(31.00°~31.78°N、121.04°~123.99°E)颗粒总磷(PP),颗粒无机磷(PIP),颗粒有机磷(POP)的季节变化和空间分布特征。结果表明,PIP是水体颗粒磷的主要存在形式;受长江径流输沙量的影响,夏季各形态颗粒磷浓度为最高,秋、冬季次之,春季对应浓度最低;不同季节,颗粒磷表现的空间分布特征也有所不同,受锋面影响,夏季颗粒磷分布范围较广,春、秋、冬季羽状锋范围内缩,颗粒磷分布范围也相应减小。通过相关性分析可知,除陆源输入外,POP的积累还与浮游植物的繁殖有关,其中部分POP可能发生矿化分解,供浮游植物生长利用。另外,PIP的解吸释放是水体中无机磷的动态补充。更多还原

【Abstract】 Based on field observations from July 2006 to December 2007,the characteristics of seasonal changes and spatial distribution of particulate phosphorus(PP),particulate inorganic phosphorus(PIP)and particulate organic phosphorus(POP) across the frontal surface(31.00°~31.78°N,121.04°~123.99°E) in Changjiang River Estuary were discussed in this paper.The results show that PIP is the main form of particulate phosphorus in the study area.Generally,distribution of different forms of particulate phosphorus is higher near the coast,and gradually declines off the coast,and the high-value area is found in maximum turbidity zone.Affected by sediment load of Changjiang River runoff,each forms of particulate phosphorus reach the highest in summer,when the concentration of PP ranges from 0.06 μmol/dm3 to 39.54 μmol/dm3.The concentration of PIP is from 0.01 μmol/dm3 to 27.16 μmol/dm3,with an average value of 2.50 μmol/dm3,which accounts for 68.24% of PP.The concentration of POP is from 0.04 μmol/dm3 to 12.38 μmol/ dm3,with an average value of 1.16 μmol/dm3,which accounts for 31.76% in total PP.The concentration in autumn and winter is next to that in summer.The concentration of PP in autumn is from 0.08 μmol/dm3 to 26.31 μmol/dm3,and POP accounts for 33.45% of PP.In winter it’s from 0.08 μmol/dm3 to 11.55 μmol/dm3,and POP accounts for 28.27% of PP.In spring,the corresponding concentration is the lowest,and the concentration of PP is from 0.05 μmol/dm3 to 8.69 μmol/dm3,and the POP accounts for 39.62% of PP.So we can conclude that the percentage of POP in PP is lowest in winter,and increases in spring and autumn,which might related to the accumulation of phytoplankton growth with the raising temperature.The spatial distribution of particulate phosphorus differs in different seasons.To some extent,the plume front plays a role similar to a barrier in the study area,which obstructs the transportation of nutrients and the particulate matter from costal sea to open waters.So the concentration of particulate phosphorus decreases gradually with increasing salinity during its transportation from west to east,but the concentration of each species to the east of 123°E reduce sharply to approximately 0,as it is hard to cross over 123°E.Under the action of frontal surface,the distribution range of particulate phosphorus in summer is large,and it decreases because of the recession of the plume front in spring,autumn and winter.Correlation analysis shows that the accumulation of POP is related to the phytoplankton reproduction.Phosphorus limitation is found at 2 m and 5 m layers at Station M4-7 and Station M4-8,which means the dissolved phosphorus cannot meet the demand of the phytoplankton growth,and part of the POP may be decomposed by mineralization for the use of phytoplankton growth.In addition,particulate inorganic phosphorus/suspended particulate matter(PIP/SPM) displays good correlation with salinity in summer(R2=0.827 3).PIP/SPM gradually decrease with the salinity increase from the coastal to the open water,which indicates that the ratio of PIP to PIM(articulate inorganic matter) has negative relationship with salinity.And that the desorption and release of PIP is dynamic supplement of inorganic phosphorus in the water column which provides essential nutrients support for phytoplankton growth.更多还原