海洋生物固氮作用研究进展  

Advances in marine biological nitrogen fixation studies

作　　者：张润[1] 陈敏[1] 

机构地区：[1]厦门大学海洋学系,福建厦门361005

出　　处：《台湾海峡》2010年第3期428-433,共6页Journal of Oceanography In Taiwan Strait

基　　金：国家自然科学基金资助项目(90411016);国家重点基础研究发展计划资助项目(2005CB422305);国际海底区域研究开发"十一五"资助项目(DYXM-115-02-4-06)

摘　　要：近年来,海洋生物固氮作用研究已成为海洋氮循环研究热点之一,因为它补充了海洋中的结合态氮,影响着海洋氮储库的收支平衡,进而调控海洋的初级生产力,并因此与海洋颗粒有机碳的迁出以及海洋对大气CO2的吸收密切相关.海洋生物固氮作用的研究主要是在近30a开展起来的,现有观点认为全球海洋生物固氮速率为100～200 Tg/a.15N2示踪法和乙炔还原法是最重要的生物固氮速率实测方法,而硝酸盐异常指数法1、5N同位素收支平衡法、卫星遥测法等则是重要的间接估测方法.束毛藻曾被认为是全球海洋最重要的固氮生物,但近年来也发现了固氮生物在微微(pi-co)级和微(nano)级的分布,表明以往基于束毛藻的固氮速率可能是被低估的.海洋生物固氮作用营养盐限制的研究主要集中在铁和磷这2个元素的作用,但目前尚无定论.在中国边缘海生物固氮作用的研究还很匮乏,少数研究表明除黑潮区外,由束毛藻所支持的固氮速率并不高.就海洋固氮作用研究的未来发展,指出今后必须在更大时空尺度上开展海洋生物固氮作用研究,以弥补现有实测数据的不足,并获取固氮微生物种类组成的准确信息,在确定海洋生物固氮作用控制因素的同时,追踪新固定氮的流向,进而为海洋氮循环提供准确信息.Nitrogen fixation has become a focus in the study of the marine nitrogen cycle during the past decade.Nitrogen fixation provides nitrogen to the ocean and affects the budget balance of the marine nitrogen pool,thereby regulating marine primary productivity.In addition,nitrogen fixation is closely related to POC export and the sequestration of atmospheric CO2.Many marine nitrogen fixation studies have been conducted in the last 30 years,and it is generally accepted that the global nitrogen fixation rate ranges from 100～200 Tg/a.A 15↑N2 tracer assay and acetylene reduction assay were found to be the most important methods for the direct measurement of nitrogen fixation rate,while the nitrate anomaly method,15↑N isotope balance method,and remote sensing played key roles in estimating the nitrogen fixation rate.Trichodesmium used to be considered the most important nitrogen fixer,while the discovery of diazotrophic picoplankton and nanoplankton revealed that previously published global nitrogen fixation rates may be underestimated.Studies of the nutrient limit of nitrogen fixation generally focused on Fe and P;however,it is still not clear to what extent these two elements limit nitrogen fixation in the ocean.Nitrogen fixation studies in China＇s marginal seas remain scarce,although a few studies showed that Trichodesmium-based nitrogen fixation was low except in the Kuroshio area.Overall,the results of this study indicate that more field studies must be conducted on a large spatial and temporal scale to obtain nitrogen fixation rates and the species of nitrogen fixing microorganisms.The ultimate controls on marine nitrogen fixation should be clearly identified.In addition,the flow of newly fixed nitrogen must be tracked to provide useful information for marine nitrogen cycle.

关 键 词：海洋化学 海洋固氮作用 固氮生物 营养盐限制 中国边缘海 

分 类 号：P734[天文地球—海洋化学]