Viruses in Marine Food Webs

9634028福尔曼虽然现在认为病毒是海洋食物网中的主要参与者，但我们对这些食物网中的病毒“生物量”发生了什么知之甚少。这个主题很重要，因为有相当一部分海洋初级生产力通过病毒“隔间”传播，约占总海洋初级生产力的10%。虽然人们一直假设这种物质被细菌利用，但还没有关于这种物质的实际命运或转化或分解速度的研究。该项目将使用实验室和实地研究相结合的方法来确定病毒分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路线传播的速度。一种主要的方法是对病毒感染的产品进行放射性标记，对产品进行纯化，然后添加到淡水中。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不同时间和地点之间的可变性。还建议开发一种用胶体金标记自然病毒的方法，然后使用基于电子显微镜的类似于“同位素稀释”的分析来同时估计每种标记的病毒形态类型的产量和损失率。这些信息应该会提高我们形成海洋微生物食物网的概念和数字模型的能力。它还应被证明有助于对海洋溶解有机物周转的更广泛的研究(病毒在实际操作中属于这些有机物)，现在看来，这在全球地球化学循环中具有相当重要的意义。***

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. ***