Moodley L, Hess C
Biol Bull. 1992 Aug;183(1):94-98. doi: 10.2307/1542410.
Ammonia beccarii is irregularly distributed in the subtidal sediment of the southern North Sea, with substantial numbers occurring as deep as 35 cm below the water-sediment interface. Deep infaunal specimens are insensitive to high oxygen concentrations (+/-225 {mu}M), and all specimens isolated from different depth intervals continued their normal activities (feeding and growth) when exposed to dysaerobic oxygen content (<12.5 {mu}M). Specimens of E. excavatum, Q. seminulum, and E. scabra, when subjected to the same conditions, behave similarly to A. beccarii. These benthic foraminifera have very low oxygen requirements. The chambers of A. beccarii that are formed in situ at different depth intervals in the sediment have a wide range in the porosity (i.e., % of area occupied by pores) which is adequate for gas exchange under both high and low oxygen conditions. However, chambers formed in the laboratory under dysaerobic conditions have a significantly higher porosity (mainly due to larger pores) than do chambers constructed in well oxygenated water. Foraminifera live at the oxic-anoxic boundary throughout the sediment and therefore must occasionally be subjected to completely anoxic conditions. A. beccarii, E. excavatum, and Q. seminulum actively survived at least 24 h without oxygen, indicating that they are capable of facultative anaerobic metabolism.
扁平鹿角珊瑚在北海南部潮下带沉积物中分布不均，大量个体出现在水 - 沉积物界面以下35厘米深处。深层底内生物标本对高氧浓度（±225 μM）不敏感，并且从不同深度区间分离出的所有标本在暴露于缺氧氧含量（<12.5 μM）时仍能继续其正常活动（摄食和生长）。在相同条件下，艾氏筛板珊瑚、半管小拟球藻和粗糙卷转虫的标本表现与扁平鹿角珊瑚相似。这些底栖有孔虫的需氧量非常低。在沉积物中不同深度区间原位形成的扁平鹿角珊瑚的房室孔隙率范围很广（即孔隙所占面积的百分比），这足以在高氧和低氧条件下进行气体交换。然而，在缺氧条件下实验室中形成的房室孔隙率明显高于在含氧充足的水中构建的房室（主要是由于孔隙较大）。有孔虫生活在整个沉积物的有氧 - 缺氧边界，因此偶尔必须经历完全缺氧的条件。扁平鹿角珊瑚、艾氏筛板珊瑚和半管小拟球藻在无氧条件下至少能活跃存活24小时，这表明它们能够进行兼性厌氧代谢。
