Dissertation Research: Production of Microbial ExtracellularPolysaccharides and Their Assimilation by Stream Invertebrates

微生物细胞外多糖普遍存在于 覆盖在水下的lotic表面的epilithon，但他们的 这些生态系统中碳转移的重要性尚不清楚。 这项拟议中的研究将估计细菌和 藻类生物量和微生物胞外产物 在Ogeechee河的木材基质上的多糖，第六 命令黑水河，并衡量效率， 若虫可吸收胞外多糖 和寡毛纲动物。 细胞外同化 多糖将通过使用14C的饲养研究来确定 标记的胞外多糖。 这些多糖 将从产生粘液的细菌培养物中纯化出来， 都是从淹没在奥吉奇河中的木头中分离出来的 河边水槽中的橡木榫钉将用作 微生物定植 如果胞外多糖被 淡水无脊椎动物、微生物对 无脊椎动物的生产力将远远大于建议， 估计的细胞消耗量。 的同化 这些微生物代谢产物可能有助于满足 在许多水生栖息地， 细胞微生物生物量不足以满足 需求 本研究具有重要的生态学基础意义 并产生对流管理有意义的结果。 学生的导师是一位优秀的科学家， 住宿条件很好。 生态系统研究计划建议支持这一点 博士论文改进项目。

Microbial extracellular polysaccharides are ubiquitous in the epilithon covering submerged lotic surfaces, yet their significance to carbon transfer in these ecosystems is unknown. The proposed research will estimate production of bacterial and algal biomass and the production of microbial extracellular polysaccharide on wood substrates in the Ogeechee River, a sixth order blackwater river, and measure the efficiency with which extracellular polysccharide may be assimilated by nymphal ayflies and by oligochaets. Assimilation of extracellular polysaccharide will be determined by feeding studies using 14C labelled extracellular polysaccharides. These polysaccharides will be purified form cultures of slime-producing bacteria which have been isolated from wood submerged in the Ogeechee River. Oak dowels in stream-side flumes will be used as subtrates for microbial colonization. If extracellular polysaccharides are assimilated by freshwater invertebrates, the contribution of microbes to invertebrate productivity would be much greater than suggested by estimates of cellular consumption alone. The assimilation of these products of microbial metabolism may contribute to meeting detritivore carbon requirements in many aquatic habitats where cellular microbial biomass is insufficient to meet detritivore needs. This research should be of significant basic ecological interest and produce results with meaning for stream management. The student's mentor is an excellent scientist, and institutional accommodations are good. The Ecosystem Studies Program recommends support for this doctoral dissertation improvement project.