2014年秋季黄河口附近海域营养现状与评价

Status and evaluation on nutrients for the adjacent sea water of the Yellow River estuary in autumn of 2014

  • 摘要: 根据2014年10月对黄河口附近海域56个站位水质的调查结果,分析了该海域营养盐的空间分布特征,并对该海域的营养水平和有机污染状况进行了评价。结果表明,该调查海域表、底层无机氮(DIN)平面分布表现为近岸向远岸降低的趋势,特别是在黄河口附近有高值区,且与盐度有显著负相关性,表明DIN主要来自黄河等入海径流的输入。表层海水中活性磷酸盐(PO4-P)平面分布表现为东北高西南低的趋势;底层海水中PO4-P平面分布较为均匀;PO4-P与海水盐度相关性不十分显著,表明调查海域PO4-P的补充并非主要来自黄河口等河流输入,而可能与有机物的分解矿化再生、浮游植物的大量繁殖以及海底表层沉积物中PO4-P向上输送补充等因素有关。从营养盐结构看,本次调查海域N/P均值大于Redfield比值;P与N相比显得相对缺乏。根据N/P比值与浮游植物生物密度平面分布表明,过高比值的N/P可能引起浮游植物的生长受到某一相对低含量元素的限制,从而导致浮游植物的生物密度较低。根据富营养化指数评价和有机污染综合指数计算结果,2014年秋季黄河口附近海域已处于富营养化状态,而DIN应是造成黄河口附近海域富营养化的主要因子;该海域有机污染程度属于2级,表明该海域开始受到有机污染。

     

    Abstract: According to the survey of sea water of 56 stations for the adjacent waters of the Yellow River estuary in October of 2014, the characteristics of nutrients distribution were analyzed, and the level of eutrophication and organic pollution situation was evaluated. The results showed that due to the influence of runoff of the Yellow River, the horizontal distribution of both surface layer and bottom layer of DIN showed a decreasing trend from nearshore area to offshore area, especially the highest value appeared in the waters of the Yellow River estuary. Also there was significant negative correlation between DIN and salinity. However, the horizontal distribution of surface layer of PO4-P showed an increasing trend from nearshore area to offshore area, while the bottom layer of PO4-P was well distributed. And there was not significant correlation between PO4-P and salinity. It was indicated that the main source of PO4-P was not mainly from the runoff such as Yellow River, but interrelated to the regeneration of the decomposition and mineralization of organic materials, the blooms of phytoplankton, and the delivery upwards of PO4-P from the surface seabed sediments and so forth. Based on the structure of nutrient salts, the ratio of N/P in the survey area was higher than Redfield ratio, where P was relatively lack compared to N. Based on the horizontal distribution of the ratio of N/P and the density of phytoplankton, too higher ratio of N/P may result in the growth of phytoplankton limited by a relatively low content element, so as to a low density of phytoplankton. According to the results of eutrophication index and organic pollution index, it was in the nutrition status in the survey area of Yellow River estuary in autumn of 2014, where DIN should be the main factor of eutrophication of sea waters of the Yellow River estuary. The grade of organic pollution of the survey area belonged to the second level, which showed that the survey area started to be polluted by organic materials.

     

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