辽河河口湿地沉积物中全氮时空分布的变化规律

Temporal and Spatial Variations of Total Nitrogen in Liaohe Estuary Wetland during the Growth Period of Reed

通过对辽河河口湿地沉积物中全氮(TN)进行为期两年的采样测定,对芦苇生长期内辽河河口湿地沉积物中全氮的时空变化进行了研究。通过此研究,能清楚的认识湿地全氮在时间空间上的变化规律,并且能通过全氮的变化情况了解湿地的富营养化的状况。以该湿地主要植被-芦苇的各个发育期为时间节点,以湿地各功能区(实验区,缓冲区和核心区)及远河区和近河区为空间区域,并根据该湿地沉积物的厚度情况,分别对深度为0~10,10~20,20~30,30~40,40~50cm的沉积物进行样品采集和测定,对沉积物中TN含量的变化规律进行分析。分析结果表明:远近河区沉积物中的TN含量在时间上的差异性非常显著(p<0.05);远近河区的沉积物中TN含量在芦苇的萌芽期时(4和5月)上升,营养发育期(5,6和7月)TN含量差异较小,芦苇的生殖期沉积物中(7,8和9月)TN含量下降,而芦苇成熟期(9和10月),在湿地远河区的TN含量很低,在近河区,9月沉积物中TN含量较低,10月TN含量急剧上升。远近河区在空间上,横向的TN差异性显著(p<0.05),纵向上差异不明显;各功能区的沉积物中TN含量为实验区>缓冲区>核心区,且各功能区的边界上TN含量较高;多数月份沉积物的表层0~30cm深度TN含量出现累积峰值,只有少数的月份在30~50cm的深度上出现累积峰,并且TN含量在各个深度(0~50cm)呈现较好的线性相关关系,相关性系数在0.72以上。通过对辽河河口湿地沉积物中TN含量时空变化规律的研究,为合理开发湿地和控制湿地富营养化,以及探究氮含量提供有效的数据支持。

The total nitrogen（TN） was sampled and measured in the sediments of Liaohe estuary wetland for two years. The temporal and spatial variation of total nitrogen in the sediments during the growing period of reed was studied. Through this study, we could clearly understand the TN change patterns of wetland, and understand the eutrophication status of wetlands through the changes of TN. According to the thickness of the wetland sediment, the samples were divided to 0-10 cm, 10-20 cm,20-30 cm, 30-40 cm, and 40-50 cm. The wetland plants were dominated by reeds, and the study analyzed the TN contents of different growth cycles of reeds, the different function areas（experimental area, buffer area and core area） of wetland and the difference near and far the riverfront to research the patterns of the change. The result of analysis showed tht the TN contents had a significant difference in the time scale near and far the riverfront（p〈0.05）, and in the germination stage of reed（April and May）, the TN contents were rising, and there were slight difference the TN contents in the vegetative stage（May, June and July）, and in the reproductive stage of reed（July, August and September）, the TN contents were decreased. During the maturation stage of reed（September and October）, the TN contents were very lower in the far riverfront, but the TN contents were sharp increased from September to October near the riverfront. In space, the TN contents had a significant difference in longitudinal sediment section near and far the riverfront（p〈0.05）, and the differences of transverse sediment section were not obvious. The TN contents of each function area were that experimental area was higher than buffer area, and buffer area was higher than core area. The TN contents were higher in the boundary of the function area. There was TN contents peak value in most of monthsin the surface depth of 0-30 cm. The TN cumulative peak value occurred on the 30-50 cm depth in few months. It revealed better line correlation of the TN contents between different depths, and the coefficient of the correlation reached above 0.7. By studying the variations of the contents of TN in time and space, it was clear to understand the change patterns of TN, what is more, it could provide data for rational usage, wetland eutrophication control and exploring the wetland nitrogen contents.