【作者】 吴鹏；

【导师】 孙耀；

【作者基本信息】 中国海洋大学 ， 海洋化学， 2007， 硕士

【摘要】 本论文在对东、黄海典型海域进行大面积调查的基础上,选择有机碳、生物硅、不同形态的氮和磷等作为古生产力和相应营养状况评估的替代指标,分析了该区近代沉积中有机碳、生物硅、不同形态氮和磷的分布特征,同步探讨了古生产力指标(总有机碳、生物硅)与浮游植物现存量和相应营养状况替代指标(氮、磷形态)之间的相关性,获得主要研究结果如下:(1)黄、东海典型区域近代沉积中古生产力指标的分布长江口及其邻近区域近代沉积中生物硅(BSi)、总有机碳(TOC)含量近岸大于远岸。从垂直变化来看,总有机碳(TOC)在两柱状样中随深度增加,没有明显的变化。生物硅(BSi)除出现两峰值外,随深度的增加,含量变化不明显。这可能与长江口复杂的水动力条件、氧化还原条件和较大的沉积速率有关。南黄海中部近代沉积中生物硅(BSi)、总有机碳(TOC)整体趋势均表现为西部沿岸较东部要高。从垂直变化来看,总有机碳(TOC)从上到下总有机碳(TOC)含量随深度的增加逐渐降低,与有机碳的化学成岩过程一致。生物硅(BSi)含量在8cm左右出现最大值,整体而言,没有明显的变化。(2)黄、东海典型海域沉积物中氮、磷的形态与分布长江口沉积物中,铁锰氧化态氮(IMOF-N)是可转化态氮的优势形态,受长江冲淡水影响,TN及各形态氮的较高含量分布在长江口偏东北方向。受氧化还原环境条件影响,随深度增大离子交换态氮(IEF-N)、铁锰氧化态氮(IMOF-N)、碳酸盐结合态氮(CF-N)呈降低趋势;总氮(TN)、有机态和硫化物结合态氮(OSF-N)垂直变化呈先增加后减小趋势,但两柱状样变化深度不同。长江口沉积物中碎屑磷(De-P)是磷的优势形态,受长江冲淡水与各海流的共同作用碎屑磷(De-P)的平面分布复杂。有机磷(Or-P)和Fe结合态磷(Fe-P)的含量相对较低。总磷(TP)及各磷的形态的含量近岸高,远岸低。自生磷(Au-P)含量高值区出现在123E附近,与浮游动物总生物量的高值区一致。从垂直分布看,碎屑磷(De-P)、自生磷(Au-P)、总磷(TP)自上而下有明显的增加。有机磷(Or-P)自上向下具有减小的总趋势,交换态磷(Ex-P)的垂直变化趋势与有机磷(Or-P)相反。Fe结合态磷(Fe-P)受氧化还原的影响较大,自上而下降低。长江口潜在生物有效性磷的平均含量约占总磷(TP)的10.08%-11.02%,仅仅是沉积磷库中的一小部。南黄海所调查的海区,氮的各赋予形态的高含量值分布在调查区域的西北部,基本趋势从西北向东南减少与南黄海中部细粒度组分较高的区域相符。有机态和硫化物结合态氮(OSF-N)是氮的主要赋予形态,有机态和硫化物结合态氮(OSF-N)含量的垂直分布,表层1-2cm内显著降低,总氮(TN)平均含量随深度增加,逐渐降低。离子交换态氮(IEF-N)含量表层1-2cm内显著降低,随后基本保持不变,与有机态和硫化物结合态氮(OSF-N)的垂直分布相似。受陆源输入、沉积环境影响,碳酸盐结合态氮(CF-N)垂直变化较为复杂,铁锰氧化态氮(IMOF-N)自上而下先增大后减小。可转化态氮占总有机碳(TOC)的20%,其含量相对其他海域含量较小,说明此处能参与氮循环,可被再次利用的氮含量较小。南黄海所调查的海区沉积物中,受黄海中部沉积中心的影响,各形态磷的最大值一般出现在10694、12494站位,交换态磷(Ex-P)表现较为明显。交换态磷(Ex-P)的垂直变化上下波动较大,与有机磷(Or-P)的矿化分解密切相关。Fe结合态磷(Fe-P)易解析,含量小,垂直变化最为复杂,从上向下波动较大;说明陆源物质对黄海中部影响不大。自生磷(Au-P)与碎屑磷(De-P)占总磷(TP)的50%以上是P的优势形态。由于黄海中部沉积环境平稳,自生磷(Au-P)、碎屑磷(De-P)自上向下平稳增大。(3)沉积物中氮、磷形态与总有机碳(TOC)、生物硅(BSi)的相关性分析做长江口及南黄海中部沉积物中各形态氮、磷与总有机碳(TOC)、生物硅(BSi)含量作线性相关性分析,结果显示:长江口沉积物中自生磷(Au-P)、碎屑磷(De-P)同生物硅(BSi)呈显著负相关,交换态磷(Ex-P)、Fe结合态磷(Fe-P)与总有机碳(TOC)呈显著正相关性;南黄海沉积物中有机磷(Or-P)、交换态磷(Ex-P)、Fe结合态磷(Fe-P)与生物硅(BSi)呈正相关性,自生磷(Au-P)、碎屑磷(De-P)同总有机碳(TOC)呈显著正相关,交换态磷(Ex-P)、Fe结合态磷(Fe-P)在适当条件下,均有利于生物利用。就各形态氮而言,长江口沉积物中有机态和硫化物结合态氮(OSF-N)、离子交换态氮(IEF-N)与生物硅(BSi)的显著正相关,铁锰氧化态氮(IMOF-N)同总有机碳(TOC)呈显著正相关;南黄海沉积物中只有碳酸盐结合态氮(CF-N)与生物硅(BSi)、有机态和硫化物结合态氮(OSF-N)与BSi表现出显著正相关性,其余氮形态与总有机碳(TOC)、生物硅(BSi)相关性都不大。(4)初级生产力的近代沉积记录及沉积物中生物硅(BSi)、总有机碳(TOC)与浮游植物现存量的相关性分析长江口及其邻近海域近代沉积中总有机碳(TOC)、生物硅(BSi)垂直分布与浮游植物量的历史长期变化并不一致,可能与长江口复杂的水动力条件及氧化还原条件有关。在南黄海中部两柱状样约为近150年来的沉积物,总有机碳(TOC)、生物硅(BSi)的变化与近150年来初级生产力的长期变化有关,其中生物硅(BSi)的含量在8cm左右出现最大值与60年代浮游植物量峰值相符。南黄海中部、长江口柱状沉积物中生物硅(BSi)、总有机碳(TOC)含量与水体中浮游植物现存量相关性不显著,但长江口H1-18站位柱状样中,沉积物中生物硅(BSi)与浮游植物现存量可建立线性关系,能更好的反映水体中浮游植物现存量,但考虑到缺少精确的测年数据及所调查区域复杂的沉积环境等因素影响,此线性关系还有待进一步研究。更多还原

【Abstract】 Based on the observation in the typical areas of the East China Sea and the Yellow Sea BSi ,TOC, nitrogen forms and phosphorus forms data were used as the productivity and nutrient proxies.Three major aspects are addressed: distribution of BSi ,TOC, nitrogen forms and phosphorus forms in sediment, the correlations between BSi(TOC) and phytoplankton standing stock, the correlations between phosphorus(nitrogen) forms and BSi(TOC). The major results can be summarized as following:(1) Distribution of BSi and TOCThe BSi and TOC concents in sediments were high in the west investigated region.. In sediments of Yangtzi River estuary ,the TOC concents fluctuated with the depth and without the variation regularity. BSi contents, except for an maximum at the depth of 10 cm, the contents of BSi had no significant chages.In sediments of the central part of the south yellow sea. the TOC concents decreased and the BSi concents without significant chages with the increasing depth.(2)Distribution of phosphorus and nitrogen forms in sedimentIn sediments of the Yangtzi River estuary, IMOF-N is the main forms of transferable nitrogen. In the influence of changjiang diluted water,TN and nitrogen forms was higher in Northeast. In the influence of oxidation and reduction, IEF-N ,.IMOF-N and CF-N contents decreased with the depth. TN and OSF-N contents increased at first and then decreased with the depth.De-P is the main forms of TP and Or-P, Fe-P contents is comparative lower than other forms in the Yangtzi River estuary. TP, phosphorus and nitrogen forms concents is high in the nearshore of the Yangtzi River estuary because of continental input effect。De-P is the main forms of TP, accounts for 56.45% of TP and complexity in horizontal distribution. Au-P concents were high in 123E region and coincided with primary productivity. Vertical distribution of De-P, Au-Pand TP increase significantly with depth. Or-P concents showed a tendency to increase and vertical distribution of Ex-P and Fe-P has opposite to action. Phosphorus bioavailability is only little, accounts for 10.08%-11.02% of TP.Nitrogen forms contents was high in the northwest of the south yellow sea and is similar to distribution of fine-grained components. OSF-N were the predominant forms in the research area , accounted for 85% of TP and vertical distribution decreased in the surface sediment, IEF-N,OSF-N concents showed Similar distributing characteristics. Because of continental input and sediment environmenta effect vertical distribution of CF-N showed complex. IMOF-N in sediment cores increases at first and decreases later downwards Transferable nitrogen accounts for 20% of TOC and was rela tively smaller than others.Because of the influence of depositional center phosphorus forms contents is high in the 10694、12494 sediment cores especially Ex-P contents which is closely related to mineralization of Or-P. Decomposable Fe-P contents in sediment cores are small and vary greatly with the depth which suggested terrigenous sediment had notable influence on the central part of the south yellow sea. Au-P and De-P were the main forms of TP, accounts for 50% of TP and gradually increased with the depth.(3) The correlations between phosphorus (nitrogen) forms and BSi(TOC).In sedimengt of the Yangtzi River estuary, Au-P and De-P contents correlate negatively to the BSi contents. The Ex-P and Fe-P contents in sediments had close relation with TOC. OSF-N and IEF-N contents are correlated with BSi contents positively. There was positive correlation between IMOF-N and TOC.In the central part of the south yellow sea, there was positive correlation between Or-P, Fe-P, Ex-P and BSi, as to Au-P, De-P and TOC, CF-N and BSi.The rest of nitrogen forms had no correlation with TOC and BSi in the 10694 station.(4) Recent sedimentary records of primary production and the correlations between BSi (TOC)and phytoplankton standing stockIn sediments of the Yangtzi River estuary, the vertical distribution of TOC and BSi in different in long-term changes of phytoplankton quantity, which maybe relate to hydrodynamic factors and the redox conditions. Maximum value in vertical distribution of TOC,BSi in the yellow sea were in accordance with maximum valueof phytoplankton quantity in 1960s in sediment of 10694,10294 station.In the central part of the south yellow sea and the Yangtzi River estuary sea area, the TOC and BSi contents have no correlations with the phytoplankton standing stock. But there were linear relationship between BSi and the phytoplankton standing stock in sediment of H1-18 station which remained to be studied further considering lack of dating data.更多还原