Microbial Degradation of Detrital Lignocelluloses in Marine Environments: Production and Fate of Particulate and Dissolved Degradation Products

海洋环境中木质纤维素碎屑的微生物降解：颗粒和溶解降解产物的生产和命运。霍德森将继续研究微生物在海水和沉积物中的转化和木质纤维素的命运。木质纤维素是沿海和河口海洋植物及其分解产物的主要成分。因此，它代表了海洋食物网潜在的主要碳来源。然而，木质纤维素是高度难降解的微生物和大多数动物不消化。在这种丰富的聚合物中的碳进入食物网之前，需要微生物转化为部分降解产物或微生物生物量或两者兼而有之。Hodson开发了几种新的方法，用于制备和跟踪来自盐沼和热带红树林沼泽的原生海洋植物的特定放射性标记木质纤维素的微生物转化。他的研究揭示了木质纤维素在海洋和陆地/淡水环境中命运的基本差异，他和他的同事们积累了在厌氧和厌氧条件下木质纤维素矿化率的基本数据，以及几种海洋环境中细菌利用木质纤维素产生的碳的相对效率。本研究将采用新的方法来跟踪木质素和木质纤维素在海洋环境中的转化，并扩大研究范围，以检查生产速度、细菌利用效率和由颗粒碎屑木质纤维素降解产生的溶解有机化合物的周转率。首席研究员将使用时间序列方法来扩展他的数据集，包括在一个月到几年的时间内，来自盐沼和红树林海洋环境的木质纤维素碎屑的生物可降解性、溶解率和微生物生物量的掺入率的变化。这些信息将有助于准确预测木质纤维素碎屑物质的持久性及其在海洋食物网中的重要性。

Microbial Degradation of Detrital Lignocelluloses in Marine Environments: Production and Fate of Particulate and Dissolved Degradation Products. Hodson will continue his studies on the microbial transformations and fate of lignocellulose in marine waters and sediments. Lignocellulose is a major component of coastal and estuarine marine plants and resulting decomposition products. Thus, it represents a potentially major source of carbon to the marine food web. However, lignocellulose is highly refractory to microbial degradation and indigestible to most animals. Microbial transformations to partial degradation products or microbial biomass or both is required before carbon from this abundant polymer can enter the food webs. Hodson has developed several new methods for preparing and following the microbial transformations of specifically radiolabeled lignocelluloses from native marine plants in salt marshes and tropical mangrove swamps. His studies have revealed basic differences in the fate of lignocellulose in marine and terrestrial/freshwater environments, and he and his colleagues have accumulated basic data on rates of lignocellulose mineralization under areobic and anaerobic conditions, and on the relative efficiencies with which bacteria in several marine environments utilize carbon derived from lignocellulose. The present study will employ new methodologies for following lignin and lignocellulose transformations in marine environments and expand the research to examine the rates of production, efficiencies of bacterial utilization, and rates of turnover of dissolved organic compounds derived from the degradation of particulate detrital lignocelluloses. The principal investigator will use a time-series approach to expand his data set to include changes in biodegradability, rates of solubilization, and rates of incorporation into microbial biomass of lignocellulosic detritus from salt marsh and mangrove marine environments over periods ranging from one month to several years. This information will enable the accurate prediction of the persistence of lignocellulosic detrital material and its importance in the marine food web.