ABR: Refining and Broadening of a Method for Estimating Productivity of Coastal-Marine Eucaryotic Decomposer Microbes

这个项目的PI设计了一种技术，几乎可以估计真核海洋微生物有机渗透营养体(真菌)的瞬时产量，类似于以前可用于原核生物有机渗透营养体的技术。发表在《生态学杂志》上的这种方法代表着一项技术突破；它有望首次估计海洋边缘生态系统中的真菌生产力，海洋环境中真菌可能对碳流产生最大影响的部分，从维管植物到海洋食物网。这项技术(缩写为Ac-ERG)包括测量放射性标记的乙酸酯与(几乎)唯一的真菌类固醇--麦角甾醇的结合。AC-ERG技术是不成熟的；这个项目将通过试验它的几个方面来完善它，以了解它的优点和缺点，并更好地定义它的易用性和适宜性范围。AC-ERG技术有两个明显的局限性：1)对水下样品的限制(潮间带植物的大部分嫩芽的分解发生在嫩芽不在水中时)；2)不适用于海洋卵菌(非常常见的海洋落叶的原生分解者；它们不合成麦角甾醇)。该项目将试图通过对Ac-ERG技术进行修改以消除这两个限制，从而扩大其应用范围：1)将放射性醋酸酯以挥发状态呈现给样品；2)找到卵菌特有的中性脂肪并跟踪流向它们的放射性醋酸酯。这项研究的结果应该是一种更强大、更持久、更容易理解的估计海洋真核有机渗透营养生产力的方法。

The Pi of this project has devised a technique for estimating virtually the instantaneous rate of production for eucaryotic marine microbial organo-osmotrophs (eumycotic fungi), analogous to those previously available for procaryotic organo-osmotrophs. This method, which is in in the Journal ECOLOGY, represents a technological breakthrough; it promises to permit the first estimates of fungal productivity in ocean-edge ecosystems, the portion of the marine environment wherein fungi are likely to have their greatest impact on carbon flow, from vascular plants to marine food webs. The technique (abbreviated as Ac-ERG) involves measuring the incorporation of radio-labeled acetate into the (nearly) uniquely fungal sterol, ergosterol. The Ac-ERG technique is unseasoned; this project will polish it via experimentation with several of its facets, to learn its strengths and weaknesses and better define its inter-pretability and range of aptness. Two conspicuous limitations of the Ac-ERG technique are: 1) restriction to submerged samples (much of the decomposition of shoots of intertidal plants occurs while shoots are out of the water); 2) in-applicability for marine oomycotes (very common protoctistan decomposers of marine leaf litter; they do not synthesize ergosterol). This project will attempt to try to expand the utility of Ac-ERG technique by modifying it to remove these two constraints through: 1) presenting the radio-acetate to the sample in a volatilized state; 2) finding neutral lipids peculiar to oomycotes and following radio-acetate flow to them. The results of this research should be a more powerful, more durable, and better understood means of estimating marine eucaryotic organo-osmotrophic productivity.