中文摘要：

摘要：以青岛砂质潮间带自由生活海洋线虫为研究对象，建立微型受控生态系，研究缺氧对海洋线虫群落结构和垂直分布的影响，以及环境复氧后海洋线虫群落的恢复能力。研究结果显示，海洋线虫是耐低氧的小型底栖动物类群，可通过垂直迁移来耐受缺氧造成的不利条件。但是，海洋线虫通过主动迁出而耐受缺氧条件的特性具有种的区别。研究中Pseudosteineria sp1、Rhynchonema sp1等海洋线虫通过向有氧环境的主动迁移耐受缺氧条件；Thalassironus sp1却可通过自身耐受机制抵御缺氧条件，在缺氧生境中仍能保持较高的丰度。此外，研究结果显示，当表层海洋线虫暴露于缺氧环境时，其总丰度显著降低，种类组成发生改变。Pseudosteineria sp1对缺氧环境较为敏感，可暂时陛地离开沉积物进入水层；而沉积物溶解氧恢复正常后，该种可以重新回到沉积物中。Daptonema sp1成熟个体及其幼龄个体对缺氧均具有较高的耐受性，是缺氧群落的绝对优势种。D．sp3则表现出对缺氧环境较高的敏感性。环境恢复正常，线虫群落丰度及多样性增加，Neochromadorasp1和Spilophorellasp1等具有机会种的特点，首先表现出丰度和繁殖能力的增加。但是线虫群落种类组成在受测时间内并未能完全恢复，群落结构的恢复需要更长的时间。

英文摘要：

Abstract： The community structure and vertical distribution of the nematode fauna in relation to oxygen deficiency, and their ability for recovery after re-establishment of normal oxygen conditions, were investigated in laboratory microcosms. Perspex cores of sediment （ i. d 2.9cm） were collected to a depth of 5 cm from the sandy beach in the Huiquan Bay, Qingdao （China） in November 2009, and incubated in laboratory microcosms. The vertical distribution of nematodes was examined in response to sediment inversion in these cores with the presence of an air-flushed silicone tube introducing oxygen to the sediment layer （laboratory microcosm I ）. Three cores were directly filled with fresh sea water and continuously aerated. This was the control treatment. In three other cores, the sediment was first turned upside down, imposing anoxic conditions on the original surface sediment （referred to as the upside down treatment）. Following an incubation of 1 week, peak densities of nematodes were recorded in the surface sediment in cores with oxygenation. This suggests that oxidized sediments provided favorable conditions for nematodes and indicated that these nematodes may migratein the sediment as a response to low oxygen conditions. Observations on the species level suggested that vertical migrations of nematodes are in some cases species-specific. Pseudosteineria spl and Rhynchonema spl might avoid low oxygen condition by migrating into the oxidized sediment, while Thalassironus spl could survive the reduced oxygen conditions and was found in high density in the bottom sediments with low oxygen. In laboratory microcosm II , community structure of nematodes was examined in response to anoxic conditions without the presence of an air-flushed silicone tube introducing oxygen to the sediment layer. Surface （0--2 cm） sediments were collected on March 2010 from the studied site at low tide and these layers of sediment were incubated in perspex jars （i. d. 11.5 cm; height 8.5 cm）. All jars were directl