Bacterivory in Pelagic Marine Ecosystems

兰德里9315432 在贫营养的开阔海洋中，大多数有机产品是由浮游细菌产生或通过浮游细菌传播的，因此可供通过直接拦截进食的小型有鞭毛原生动物消耗。 在与这种生物相关的空间尺度上，捕食者-被捕食者的相互作用可能是由分子和流体动力作用的平衡或液体介质中小颗粒的相对运动控制的，而不是由复杂的狩猎或回避行为控制的。 因此，有可能从物理和化学的第一原理来理解噬菌性鞭毛虫的清除率和选择性。 本文主要研究了细菌运动性和表面理化性质（疏水性和静电荷）对动鞭藻噬菌性的影响。 在生态背景下，运动性和疏水性的增强可能为贫营养环境中的浮游细菌提供生存优势。 然而，这些特征也会增加与捕食者随机接触的频率，并可能在死亡率方面造成不利影响。 Landry博士将使用综合的描述、实验和理论方法：1）表征夏威夷沃茨中天然微生物群落的大小、丰度、运动性和表面特性; 2）测试猎物运动性和表面特性对动物脂肪虫摄食率的影响; 3）确定运动性和疏水性的选择优势作为营养环境和鞭毛虫捕食的函数;和4）继续发展直接接触摄食的力平衡模型。 ***

Landry 9315432 Most of the organic production in the oligotrophic open oceans is created by or passed through bacterioplankton and consequently made available for consumption by small flagellated protozoa which feed by direct interception. At spatial scales relevant to such organisms, predator-prey interactions are likely to be controlled by the balance of molecular and hydrodynamic forces acting or small particles moving relative to one another in a liquid media, rather than by complex hunting or avoidance behaviors. Thus, it may be possible to understand clearance rates and selectives of bacterivorous flagellates from physical and chemical first principles. The present research focuses on the influences of bacterial motility and physiochemical surface properties (hydrophobicity and electrostatic charge) on zooflagellate bacterivory. In an ecological context, increased motility and hydrophobicity may provide survival advantages to bacterioplankton in oligotrophic environments. However, such characteristics would also increase the frequency of random contacts with predators and would be a likely disadvantage in terms of mortality rate. Dr. Landry will use an integrated descriptive, experimental, and theoretical approach to: 1) characterize size, abundance, motility, and surface properties of natural microbial communities in waters of Hawaii; 2) test the effects of prey motility and surface properties on feeding rates of zoofagellates; 3) determine the selective advantages of motility and hydrophobicity as a function of nutritional environment and zooflagellate predation; and 4) continue development of a Force-Balance model of direct contact feeding. ***