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可以指示陆源和海源有机质的类脂生物标志物是重建晚第四纪海洋生态环境的良好指标,但目前为止,类脂生物标志物在东海水体及沉积物中的对比研究还很缺乏。针对这一问题,于2010年6月10日至6月20日在长江口及东海陆架区采集了表层颗粒物和沉积物,研究其所含类脂生物标志物的分布并对比分析。研究的类脂生物标志物包括长链奇碳数正构烷烃(主要来自陆源高等植物),长链烯酮(来自颗石藻),菜子甾醇(主要来自硅藻),甲藻甾醇(主要来自甲藻)。研究结果表明表层颗粒物中的长链正构烷烃并未表现出奇偶优势(CPI_(25~33)平均值为1.2),主要可能受到石油烃类的影响,从而使得长链奇碳数正构烷烃对陆源有机质的指示作用发生偏差。但是表层沉积物中的长链正构烷烃表现出明显的奇偶优势(CPI_(25~33)平均值为2.9),并且长链奇碳数正构烷烃有近岸高离岸低的分布趋势,与长江陆源物质对东海的输入模式相似。颗粒物与沉积物中长链正构烷烃的分布特征不同,可能主要与石油污染、时间尺度和有机质来源的空间差异有关。研究结果表明东海表层颗粒物中海源生物标志物菜子甾醇和甲藻甾醇的分布与以往浮游植物调查结果基本一致,在研究区域中部南北各存在一高值区,主要受控于初级生产。表层沉积物中这两种海源生物标志物的分布与表层颗粒物不同,在研究区域内呈现近岸和外海高,中间低的趋势。导致表层颗粒物和沉积物中海源生物标志物不同分布的原因为:表层颗粒物中的有机质主要由某个季节在表层产生的,而表层沉积物中的有机质主要是反映了年或者几年平均的水柱输出生产力。此外,表层的有机质在输出到沉积物中的过程中还受到迁移、转化、降解以及粒度等沉积环境因素的影响。因此某个季节的表层颗粒物中的类脂生物标志物同表层沉积物中的这些化合物可能不具有良好的对应关系。据现有资料推测,表层沉积物中海源生物标志物可能指示了该区域多年平均的水柱积分的初级生产力。
Lipid biomarkers that can indicate organic matter from terrigenous and marine sources are good indicators for rebuilding Late Quaternary marine ecosystems. However, comparative studies on lipid biomarkers in the East China Sea waters and sediments are still scarce. In response to this problem, surface particulate matter and sediment were collected from June 10, 2010 to June 20, 2010 in the Changjiang Estuary and the East China Sea shelf area to study the distribution of lipid biomarkers contained therein and to compare and analyze them. Lipid biomarkers studied include long chain odd-numbered n-alkanes (mainly from higher terrestrial plants), long-chain ketenes (from coccolithiasis), brassicasterols (mainly from diatoms), cidostanol (mainly from Dinoflagellate). The results show that the long-chain n-alkanes in the superficial particles do not show the even and odd advantages (the average value of CPI_ (25-33) is 1.2), which may be mainly affected by petroleum hydrocarbons, Deviations from the indicated role of terrigenous organic matter. However, the long-chain n-alkanes in surface sediments show a significant parity (average of CPI_ (25-33) is 2.9), and the long-chain odd-carbon n-alkanes have the tendency of low nearshore and low offshore distribution, Similar to the input pattern of the terrestrial source material of the Yangtze River to the East China Sea. The distribution characteristics of long-chain normal paraffins in particulate matter and sediment may be mainly related to the petroleum pollution, time scale and spatial differences of organic matter sources. The results show that the distribution of the marine biomarkers in the East China Sea marine biomarkers brassicasterol and dinoflast sterol are consistent with the previous phytoplankton survey results. There is a high value area in the central and southern part of the study area, which is mainly controlled by primary production. The distribution of these two marine biomarkers in the surface sediment is different from the surface particulate matter, showing a tendency of near-nearshore sea and high sea level in the study area and low in the middle. The reason for the different distribution of marine biomarkers in surface sediments and sediments is that the organic matter in the surface particulate matter is mainly produced on the surface layer in a certain season and the organic matter in the surface sediment mainly reflects the annual or several years average water column Output productivity. In addition, the surface organic matter is also affected by sedimentary environment factors such as migration, transformation, degradation and grain size during its export to sediment. Therefore, the lipid biomarkers in the surface sediments of a season may not have a good correspondence with these compounds in the surface sediments. According to available data, it is speculated that the sea-derived biomarkers in surface sediments may indicate the primary productivity of multi-year average water column integrals in the region.