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[午餐交流会] 第五十四讲:铝对海洋浮游植物生长的有益效应:修正的铁假说

发布时间:2016/04/12     浏览次数:
时间:2016-4-18 (星期一) 11:40-13:30(12:20开讲)
地点:周隆泉楼
主讲人:周林滨博士 Dr. L
来访单位:中国科学院南海海洋研究所 South China Sea Institute of Oceanology, CAS
邀请人:午餐交流会(史大林教授)
联系人:施薇

讲座摘要

铝(Al)是地壳中含量最高的金属元素,普遍存在于各类环境中,可通过河流径流和沙尘沉降输入到海洋,潜在影响海洋生物。相比较于大量研究报道Al对淡水生物的影响,少有研究关注Al对海洋浮游植物生长的效应。溶解Al在海水中的化学形态与在淡水中截然不同,因此Al对海洋浮游植物的作用机理很可能不同于对淡水生物的影响。从2010年起我们开始研究Al对海洋浮游植物生长的效应。我们几年间进行大量野外Al加富实验,发现Al加富对多种浮游植物生长的有益效应。表现为直接促进硅藻和束毛藻生长,促进群落固氮和叶绿素a浓度增加,且Al对海洋浮游植物生长的影响与周围环境中的营养盐组成有关。通过大量室内实验,我们验证了Al促进多种海洋浮游植物的生长,并揭示了在磷缺乏情况下,Al促进海洋硅藻利用溶解有机磷是其有益于海洋浮游植物生长的作用机制之一。另外,Al可使生源颗粒的溶解性降低,这都可能提高海洋生物泵的效率——使更高比例的碳输出到深海,在全球碳循环中发挥着未被认知的重要作用。我们提出了“修正的铁假说——铝假说”,也就是Al和铁一样也在冰期-间冰期大气CO2浓度变化中发挥重要作用。这为解释人为铁施肥结果与Martin铁假说不一致提供了参考。也即自然过程向海洋施铁的同时,也带来了Al等其他元素,这是人为铁施肥实验所忽略的。

Abstract

Aluminum is the most abundant metal element in earth crust, and it is ubiquitous in different environments. River runoff and dust deposition could bring them with Al into the ocean, where Al could potentially influence marine organisms. In contrast to substantial reports on the Al effects on biota in the acidic and neutral pH media, little is known regarding the effects of Al on organisms in the alkaline seawater. The Al speciation in seawater is quite different from that in freshwater, implying that the Al effects on marine phytoplankton could be different from those on freshwater organisms. We have started the journey focusing on the Al effects on marine phytoplankton since 2010. Based on substantial Al enrichment experiments in the field, we found that Al may be beneficial to the growth of several marine phytoplankton, including stimulating the growth of diatoms andTrichodesmium, and enhancing nitrogen fixation and chlorophyllaconcentration of the entire planktonic community. We also found that the Al effects on marine phytoplankton growth were associated with nutrient status in seawater. The stimulatory growth of many marine phytoplankton species was confirmed in laboratory experiments. We found that Al could enhance the diatom utilization of dissolved organic phosphorus under phosphorus-limited condition, which could be one of the mechanisms for the Al effects on marine phytoplankton. In addition, Al could reduce the solubility of biogenic particles like diatom frustules and“Tunicata houses”, and thus increase the carbon export to the deep ocean (i.e. increase the efficiency of the biological pump). Therefore, Al may play an unrecognized important role in the global carbon cycle. We would like to propose a revised Iron Hypothesis (i.e., the Al Hypothesis) that Al, as well as iron, play an important role in the glacial-interglacial change in atmospheric CO2concentration. Our hypothesis may provide alternative explanation for the inconsistence between the results of the “Artificial Iron Fertilization experiments”, and the expectation of the Iron Hypothesis proposed by John Martin. That is that natural iron fertilization such as dust deposition not only brings it with iron, but also other elements including Al, which was usually ignored by the previous Artificial Iron Fertilization experiments.

个人简介:

教育经历

2007.09-2012.06,中国科学院南海海洋研究所,海洋生物学,获博士学位

2003.09-2007.06,广东海洋大学,海洋渔业科学与技术专业,获学士学位

工作经历

2016.01-至今,中国科学院南海海洋研究所,副研究员

2014.10-2015.02,维多利亚老品牌vic3308,近海海洋环境科学国家重点实验室,访问学者

2012.11-2013.05,香港科技科大学,生命科学部,访问学者

2012.07-2015.12,中国科学院南海海洋研究所,助理研究员

研究方向:

从浮游生物粒径谱、微型浮游动物摄食和铝对海洋浮游植物生长效应三个方面认识海洋浮游生态系统生物生产过程:包括从浮游生物粒径谱的角度认识海洋浮游生态系统整体能量传递效率及状态;从微型浮游动物摄食的角度,认识海洋浮游生态系统关键环节能量传递;从铝对海洋浮游植物生长效应的角度,认识大气沉降对初级生产的影响。

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