Effect of Sediment Transport on Benthic Bacterial Growth andExoenzyme Production

据信刺激海洋沉积物中细菌并因此增强其在底栖生物群落和营养循环中的作用的因素包括营养供应增加、放牧压力和物理运输事件。戴明博士的研究将在最初简单和逐渐复杂的模拟中确定沉积物输送对两个关键细菌参数--生长和胞外酶产生的影响：静态(单核)、梯度(跨营养梯度串联的多个岩心)和流体(水槽)微观世界。将根据荧光显微镜确定的细菌丰度、生物体积和分裂细胞频率的时间和空间变化，在特定沉淀物干扰下的微观宇宙(以及未受干扰和死亡的对照)中评估生长。胞外酶活性将使用荧光底物类似物来测量。这两个过程将在选定的实验中使用射电定位方法进行交叉检查。一个主要目标是记录静止沉积物的物理干扰对随后的细菌参数(进而影响较高营养水平的食物资源)的影响程度，最终为预测自然海洋沉积物中沉积物迁移事件的影响奠定基础。

Factors believed to stimulate bacteria in marine sediments, and therefore to enhance their role(s) in benthic communities and nutrient cycles, include increased nutrient supply, grazing pressure, and physical transport events. Dr. Deming's research will determine the effects of sediment transport on two key bacterial parameters, growth and exoenzyme production, in initially simplistic and progressively more complex simulations: static (single core), gradostatic (multiple cores linked in series across nutrient gradients), and hydrodynamic (flume) microcosms. Growth will be assessed in microcosms subjected to a defined sediment disturbance (and in undisturbed and killed controls), according to temporal and spatial shifts in bacterial abundance, biovolume, and frequency of dividing cells, determined by epifluorenscence microscopy. Exoenzyme activity will be measured using fluorescent substrate analogs. Both processes will be cross-checked in selected experiments using radiosotopic approaches. A major goal is to document the degree to which physical disturbance of quiescent sediments influences subsequent bacterial parameters (which, in turn, influence food resources for higher trophic levels), ultimately building a basis for predicting effects of sediment transport events in natural marine sediments.