224Ra对春季青岛近海水体混合及营养盐来源的示踪研究

2013年3月,以青岛近海为研究区域,分析了过剩224Ra(224Raex)的分布特征及其影响因素,并以之为示踪工具对水体的混合过程和营养盐来源进行了评估。研究发现,224Raex的比活度范围为1.30.2 dpm/100 L到10.21.3 dpm/100 L,并呈现出近岸高、远岸低和低潮时高、高潮时低的时空分布特征。224Raex-盐度对研究区域的水体混合状况的指示作用明显优于温度-盐度指标。2013年3月青岛近海溶解无机磷(DIP)和溶解硅(DSi)浓度的主控因素是潮汐作用,而溶解无机氮(DIN)的来源组成较为复杂,可能包括河流输入、生活污水、工业废水、潮汐混合、地下水排放等。

Using 224Ra to track coastal water mixing process and nutrients source in Qingdao Coast

In this study,we investigated the spatio-temporal distribution of excess 224Ra (224Raex) and its influence factors in the Qingdao coast,and further used it as tracer to evaluate the water mixing process and nutrients source.The following informations were obtained:the activity of 224Raex range from 1.30.2 dpm/100 L to 10.21.3 dpm/100 L.High radium concentrations were found in nearshore and ebb tide,and low values were in offshore and high tide.We found that 224Ra-salinity was a better choice to track the water mixing process in the study area than salinity-temperature pair.The correlation of 224Raex and salinity with nutrients were used to discuss the nutrients souces.In March 2013,DIP and DSi concentrations were mainly controlled by tidal mixing in the Qingdao coast,but DIN might have multi-sources,such as riverine input,industrual and domestic wastewater,tidal mixing and submarine groundwater discharge.