Bacterivory in Pelagic Marine Ecosystems

兰德里9315432寡养开阔海洋中的大多数有机产品是由浮游细菌创造或通过浮游细菌传播的，因此可供小型鞭毛原生动物食用，这些原生动物通过直接截获的方式进食。在与这类生物相关的空间尺度上，捕食者-猎物的相互作用可能由分子和水动力的平衡或小颗粒在液体介质中相互运动的平衡控制，而不是由复杂的狩猎或回避行为控制。因此，有可能从物理和化学的基本原理来理解食菌鞭毛虫的清除率和选择性。本研究主要研究细菌的运动性和表面物理化学性质(疏水性和静电性)对游动鞭毛虫菌体的影响。在生态学的背景下，增加的运动性和疏水性可能为浮游细菌在营养稀少的环境中提供生存优势。然而，这种特征也会增加与捕食者随机接触的频率，在死亡率方面可能是一个劣势。Landry博士将使用描述、实验和理论相结合的方法来：1)描述夏威夷水域中自然微生物群落的大小、丰度、运动性和表面特性；2)测试猎物的运动性和表面特性对动物胶着体摄食率的影响；3)确定作为营养环境和鞭毛虫捕食作用的运动性和疏水性的选择优势；以及4)继续开发直接接触喂养的力平衡模型。***

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. ***