Nature and Transformations of Particulate Carbohydrates in the Oceanic Water Column

碳水化合物是所有有机食品的主要有机成分， 海洋生物，尤其是浮游植物， 这些物质构成了海洋微粒的很大一部分， 有机物（POM）。 然而，与其他 重要的生物分子群，如脂类和蛋白质， 令人惊讶的是， 海洋POM 因此，一项研究，以测试以下内容 假设：1. 在水中粒子下降的过程中 柱，储存碳水化合物优先损失， 结构多糖相对增强， 残余物 后一种化合物可用作生物标志物，而 前者的损失可以用来估计能量潜力 （热值）和POM随深度的降解速率; 2. 藻类是海洋中碳水化合物的主要来源， 在陆地附近，陆源物质可能会在当地 重要. 这些输入可以在以下基础上进行区分： 其碳水化合物组成; 3. 由于微生物 颗粒下降过程中的降解，新的多糖 形成。 在很大程度上， 在组成上不同于原始材料，因此 可用于估计微生物降解的程度 POM。 这项研究将主要基于对样本的分析 来自作为VERTEX计划一部分部署的沉积物捕集器。 分析技术将包括使用选择性 解聚与高分辨率GC和HPLC联用。 在VERTEX计划的背景下， 在蛋白质、脂质和微生物活性方面， 对碳水化合物的研究将对 对我们理解影响化学物质通量的过程 有机质和成岩作用。

Carbohydrates represent a major organic component of all marine organisms, especially phytoplankton, and thus these substances constitute a large fraction of oceanic particulate organic matter (POM). However, in comparison to other important groups of biomolecules, eg, lipids and proteins, surprisingly little attention has been paid to carbohydrates in oceanic POM. Therefore, a study to test the following hypotheses: 1. During descent of particles in the water column, storage carbohydrates are preferentially lost while structural polysaccharides are relatively enhanced in the residue. The latter compounds can be used as biomarkers, while loss of the former may be used to estimate the energy potential (caloric value) and rate of degradation of POM with depth; 2. Algae are the major sources of carbohydrates in the sea, but close to land, terrigenous sources may become locally important. These inputs can be differentiated on the basis of their carbohydrate compositions; 3. As a result of microbial degradation during descent of particles, new polysaccharides are formed. These new saccharides are to a large degree compositionally distinct from the original materials and thus may be used to estimate the degree of microbial degradation POM. The study will be based largely on analyses of samples from sediment traps deployed as part of the VERTEX Program. Analytical techniques will include the use of selective depolymerizations coupled with high resolution GC and HPLC. When put in the context of the VERTEX Program, especially work being done on proteins, lipids, and microbial activity, the proposed study of carbohydrates should contribute significantly towards our understanding of the processes affecting fluxes of organic material and diagenesis in the watr column.