NITROGEN-FIXING AND NITRIFYING SYMBIOSES IN THE MARINE ENVIRONMENT
NITROGEN-FIXING AND NITRIFYING SYMBIOSES IN THE MARINE ENVIRONMENT
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DOI：
10.1016/b978-0-12-372522-6.00027-x
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发表时间：
2008-01-01
期刊：
影响因子：
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通讯作者：
O'Mullan, Gregory D.
中科院分区：
文献类型：
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作者：
Foster, Rachel A.;O'Mullan, Gregory D.
术语“共生体”首先由De Bary（1879）定义为两个或两个以上不同名称的生物体生活在一起。虽然共生相互作用在自然界中是普遍存在的，但很少有海洋共生系统得到很好的表征，共生体对宿主的功能作用知之甚少，反之亦然。许多共生体是在真核宿主和6个蓝藻共生体或蓝藻之间。蓝细菌具有光合作用，并且许多蓝细菌能够固氮，因此通常认为蓝细菌配偶体作为宿主的碳源和/或氮源发挥作用。在涉及海绵的平行系统9中，微生物共生体通常是异养生物、石养生物和光养生物的多样性集合。海绵-微生物系统的一个统一特征是氮的交换。12营养物往往是热带13个海洋初级生产的关键限制因素，在这些贫营养生境中经常观察到共生现象。诺里斯（1967年）根据他在开阔海洋中的许多显微镜观察结果推测，相当大一部分生物区系曾在某个时期或另一个时期参与了一个财团，要么是暂时的，要么是更永久的。形成一种共生关系可能被认为是对贫营养海洋中生命的一种生态适应。18与陆地上的共生系统相比（见Rai等人，2000年），海洋共生系统19的样本量大大不足，因此，这些独特关系的许多复杂性在很大程度上仍未得到解决。分离和鉴定这21种共生体的困难一直是获得有关它们的有用信息的主要问题。[22]如果没有落射荧光显微镜，大多数这些关联都不会被注意到。23
The term “symbioses” was first defined loosely by De Bary (1879) as two or more 2 differently named organisms living together. Although symbiotic interactions are 3 ubiquitous in nature, few of the marine planktonic systems have been well characterized, 4 and comparatively less is known of the functional role of the symbiont for the host and 5 vice versa. Many of the planktonic symbioses are between eukaryotic hosts and 6 cyanobacterial symbionts, or cyanobionts. Cyanobacteria are photosynthetic, and many 7 are capable of nitrogen (N2) fixation, thus often it is presumed that the cyanobacterial 8 partner functions as a carbon and/or nitrogen source for the host. In the parallel system 9 involving sponges, often the microbial symbionts are a diverse assemblage of 10 heterotrophs, lithotrophs, and phototrophs. One unifying character in sponge-microbe 11 system is the exchange of nitrogen. 12Nutrients are often the key limiting factors to primary production in the tropical 13 seas, and symbioses are frequently observed in these types of oligotrophic habitats. From 14 his many microscopy observations in the open ocean, Norris (1967) speculated that a 15 considerable part of the biota were involved at one time or another in a consortium, either 16 temporary or more permanent. Forming a symbiotic association might then be 17 considered an ecological adaptation to life in the oligotrophic ocean. 18 Compared to their terrestrial counterparts (see Rai et al. 2000), marine symbiotic 19 systems are greatly under-sampled, and thus the many intricacies of these unique 20 relationships remain largely unresolved. Difficulties in isolating and identifying these 21 symbioses have been the primary problems in attaining useful information about them. 22 Without epifluorescence microscopy most of these associations would go unnoticed. 23