Bacterivory in Oceanic Environments: Relative Importance ofthe Heterotrophic Microbial Loop

海洋环境中的食菌：异养微生物循环的相对重要性

• 批准号: 8916165
• 负责人: Evelyn Lessard
• 金额: $ 21.29万
• 依托单位: University of Washington
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1989
• 资助国家: 美国
• 起止时间: 1989-07-01 至 1992-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=8916165&HistoricalAwards=false
• 关键词: Bacterivory; Oceanic; Environments; Relative; Importance

The role of pelagic microzooplankton in food webs of the sea has been explored sketchily in field work. Small, delicate organisms are difficult to isolate and study in the field situation. One method of studying their role is to compare food chains of widely different marine environments. The goal of this research program is to determine the relative importance of carbon transformation through the microbial loop of an oligotrophic and euptrophic oceanic community, including especially the consumers of bacterial biomass. The hypothesis to be tested is that a greater percentage of the total amount of carbon fixed by primary productivity is consumed and respsired by heterotrophic microorganisms, i.e. bacteria and protozoa, in oceanic ecosystems than in coastal ecosystems. Primary productivity, bacterial productivity, and bactivory will be measured at a coastal site and a Sargasso Sea site during three cruises in the western North Atlantic. The total amount of bacterial carbon produced and the percentage of primary production that this bacterial carbon represents will be determined in these oceanic environments and compared to the patterns of microbial carbon tranformation in two neritic environments, Chesapeake Bay and Vineyard Sound. Size fractionation and single cell isolation studies of common species of larger protozoa and microm;etazoa will be performed using radiolabelled natural bacteria in order to identify the primary consumers of bacterial biomass in these communities. %%% Much of the carbon produced in the sea is in the form of microorganisms too small to see or easily manipulate. In recent years it has become clear that these organisms are quite crucial to the food chain of the seas from the poles to the equator. One way to evaluate the importance of the microorganisms is to compare their growth rates in several different environments and to examine which organisms are able to feed on the microorganisms. This study will measure rates of growth of several types of microorganisms in contrasting environments, the relatively impoverished Sargasso Sea and the relatively fertile Georges Bank. It will also identify which organisms consume the bacteria. The expectation is that microbial production is much more important in the food chain of the Sargasso Sea than it is in the Georges Bank area.

浮游微型浮游动物在海洋食物网中的作用 在实地工作中得到了粗略的探索。 精致的小 生物体很难在野外分离和研究 形势 研究它们作用的一种方法是比较 不同海洋环境的食物链。 目标 这项研究计划的目的是确定 通过微生物循环进行碳转化的重要性 贫营养和富营养的海洋群落，包括 尤其是细菌生物量的消耗者。 的假设 需要测试的是， 初级生产力固定的碳被消耗， 由异养微生物，即细菌和 原生动物，在海洋生态系统比在沿海生态系统。 初级生产力、细菌生产力和细菌活性 将在一个沿海站点和一个马尾藻海站点测量 在北大西洋西部的三次巡航中。 总 产生的细菌碳量和 这种细菌碳所代表的初级生产 在这些海洋环境中确定，并与 两个浅海区微生物碳转化模式 环境，切萨皮克湾和葡萄园湾。 大小 分离和单细胞分离研究 将对较大的原生动物和微型动物种属进行检查; 使用放射性标记的天然细菌， 这些社区中细菌生物量的主要消费者。 %%% 海洋中产生的大部分碳是以 微生物太小，难以看到或容易操作。 在 近年来，人们已经清楚地认识到，这些生物是相当 对从两极到南极的海洋食物链至关重要 赤道 一种评估 微生物是比较他们的生长速度在几个 不同的环境，并检查哪些生物能够 以微生物为食 这项研究将衡量 几种类型的微生物的生长， 环境，相对贫瘠的马尾藻海和 相对肥沃的乔治河岸 它还将确定哪些 微生物会消耗细菌。 人们期望 微生物生产在食物链中的重要性 比在乔治海岸地区要多。