Viruses in Marine Food Webs

尽管病毒现在被认为是海洋食物网中的主要角色，但我们对这些食物网中病毒“生物量”的变化知之甚少。这一课题之所以重要，是因为海洋初级生产力总量中有相当大的一部分（约10%）通过病毒“区室”。“虽然人们认为这种物质被细菌利用，但没有研究过这种物质的实际命运，也没有研究过它转化或分解的速度。该项目将使用实验室和现场研究相结合的方法来确定病毒裂解生物体时释放的病毒物质和细胞碎片的命运，以及这些物质在微生物食物网中通过不同途径传播的速率。主要的方法是对病毒感染的产物进行放射性标记，纯化产物，然后加入新鲜海水中。该项目将研究与细菌，浮游植物和其他原生生物的相互作用。特别令人感兴趣的是，这些进程在社区内以及在不同时间和地点之间的可变性。 它还建议开发一种方法来标记天然病毒与胶体金，然后使用类似于“同位素稀释”的电子显微镜为基础的分析，同时估计每个标记的病毒形态类型的生产和损失率。这些信息将提高我们形成海洋微生物食物网的概念和数值模型的能力。它也应该证明是有用的，在海洋溶解的有机物质（其中病毒操作所属），这似乎是全球地球化学循环中具有相当大的意义的周转更一般的研究。 ***

9634028 FUHRMAN Although viruses are now thought to be major players in marine food webs, we know very little about what happens to viral "biomass" in these food webs. The subject is important because a significant fraction, on the order of 10s of %, of total marine primary productivity passes through the viral "compartment." While it has been assumed that this matter is utilized by bacteria, there have been no studies of the actual fates of this material nor of the rates with which it is transformed or decomposed. This project will use a combination of laboratory and field studies to determine the fates of viral matter and cell debris released when viruses lyse an organism, and the rates by which this matter travels through different routes in the microbial food web. A major method to be used is radiolabelling of the products of viral infection, purification of the products, and then addition to fresh seawater. The project will examine the interactions with bacteria, phytoplankton, and other protists. Of particular interest is the variability of these processes, within communities and between different times and places. It is also proposed to develop an approach to label natural viruses with colloidal gold and then use an electron microscopy-based analysis analogous to "isotope dilution" to estimate simultaneously the production and loss rates of each labelled viral morphological type. The information should improve our ability to form conceptual and numerical models of marine microbial food webs. It also should prove useful in the more general study of the turnover of marine dissolved organic matter (to which viruses operationally belong), which now appears to be of considerable significance in global geochemical cycles. ***