ROW: Laboratory Studies of Facultative Anaerobic Benthic Foraminifera

有孔虫是原生动物，通常被认为是专性需氧生物，尽管各种各样的证据表明，某些底栖生物形式是兼性厌氧生物。这项研究规划项目的目标是：(1)开发一种快速的、非末端的筛选程序，以区分活的和死亡的个体；(2)表征长期缺氧或低氧条件下的动物的超微结构；(3)建立有孔虫的死后超微结构降解序列。筛查程序将使用荧光底物，这种底物在活样本中会发出荧光，但在死亡样本中无法被荧光显微镜检测到。暴露在缺氧或低氧条件下数周至数月的标本的超微结构将用高压电子显微镜(HVEM)进行检查。由于观察切片的厚度约为常规电子显微镜切片厚度的10倍，因此使用高压电子显微镜可以快速检查大量样品。为了研究死后超微结构的变化，有孔虫将受到足以导致坏死的紫外线照射。这些标本将用高压电子显微镜检查，以评估随着时间的推移而发生的变化。本项目的研究结果将为今后研究缺氧环境中有孔虫的生理生态奠定基础。

Foraminifera are protozoans which are generally thought to be obligate aerobes although a wide variety of evidence suggests that certain benthic forms are facultative anaerobes. This research planning projects objectives are to (1) develop a rapid, non terminal screening procedure to distinguish living from dead individuals, (2) characterize formainiferal ultrastructure after exposure to extended periods of anoxia or low oxygen conditions, and (3) establish the postmortem ultrastructural degradation sequence of foraminifers. The screening procedure will employ flourogenic substrates which will fluoresce within living specimens but which are undetectable by fluorescence microscopy in dead specimens. The ultrastructure of specimens exposed to anoxic or low oxygen condition for time periods of weeks to months will be examined with high voltage electron microscopy (HVEM). The use of HVEM permits rapid examination of a significant sample size since observed section are about 10 times thicker than those for conventional electron microscopy. In order to investigate postmortem ultrastructural changes, foraminifera will be irradiated with ultraviolet light in a dose sufficient to induce necrosis. These specimens will be examined with HVEM to assess changes over time. The results of this project will provide the foundation for future investigations concerning the physiological ecology of foraminifera inhabiting anoxic environments.