春季东印度洋生源要素的分布特征及其影响因素

发布时间：2018-10-10 18:42

【摘要】：由于热带东印度洋实测资料缺乏,对该海域生源要素时空分布特征及其影响因素尚缺少清楚的认识。本文根据2013年3~5月春季东印度洋的调查资料,分析了热带东印度洋上层水体(0~300 m)温度、盐度、溶解氧、营养盐和叶绿素a等要素的分布特征,并对溶解氧极小值、第一亚硝酸盐最大值(PNM)和次表层叶绿素最大值(SCM)的形成机制进行了探讨。主要研究结果如下:(1)春季东印度洋上层水体层化明显,在80~120 m水深形成温盐密跃层。温密跃层在赤道附近最深;自赤道附近向南、北,温密跃层深度逐渐变浅。(2)与温密跃层相伴生,春季东印度洋上层水体存在显著的化学跃层(p H、DIC、DO、NO3--N、PO43--P、Si O32--Si等),且各化学要素跃层之间以及化学跃层与温密跃层之间具有高度重合性。跃层以下p H降低、DIC和营养盐含量迅速升高是有机物的氧化分解所致;同时,有机物分解大量消耗溶解氧,致使在东印度洋次表层(200 m左右)存在溶解氧极小值现象。(3)春季东印度洋次表层(75~100 m)普遍存在SCM和PNM现象,SCM和PNM位于温密跃层和营养盐跃层内中部或上界略下位置,且SCM和PNM呈斑状分布。春季东印度洋SCM的深度及量值受光照、营养盐、温密跃层的影响,且温密跃层对SCM的深度及量值起主控作用。而PNM对SCM具有追随效应,浮游植物对硝酸盐的不完全还原是形成PNM现象的主要原因。
[Abstract]:Due to the lack of measured data in the tropical eastern Indian Ocean, there is a lack of a clear understanding of the spatial and temporal distribution of biogenic elements and their influencing factors in the sea area. Based on the investigation data of the eastern Indian Ocean from March to May 2013, the distribution characteristics of temperature, salinity, dissolved oxygen, nutrients and chlorophyll a in the upper tropical Indian Ocean (0 ~ 300m) were analyzed, and the dissolved oxygen values were minimized. The formation mechanism of the first nitrite maximum (PNM) and the subsurface chlorophyll maximum (SCM) were discussed. The main results are as follows: (1) the stratification of the upper Indian Ocean is obvious in spring, and the thermo-salt dense cline is formed at the water depth of 80 ~ 120 m. The thermocline is the deepest near the equator, and the depth of the thermocline becomes shallower from near the equator to the south and north. (2) the thermocline is associated with the thermocline. In spring, there are significant chemical clines in the upper waters of the eastern Indian Ocean (O32--Si et al.), and there is a high coincidence between the chemical elements of the clines and between the chemical clines and the thermoclines. The decrease of pH below the cline, the rapid increase of DIC and nutrient content is caused by the oxidative decomposition of organic matter, and the decomposition of organic matter consumes a large amount of dissolved oxygen. (3) SCM and PNM are common in the subsurface of the eastern Indian Ocean (75 ~ 100m) in spring, and SCM and PNM are located in the middle or lower upper boundary of the thermocline and nutrient cline. The distribution of SCM and PNM were speckled. The depth and magnitude of SCM in the eastern Indian Ocean in spring are affected by light, nutrients and thermocline, and the thermocline plays a major role in controlling the depth and value of SCM. However, PNM has the following effect on SCM, and the incomplete reduction of nitrate in phytoplankton is the main reason for the formation of PNM.
【学位授予单位】：国家海洋局第一海洋研究所
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：P731

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