LIFE-HISTORY OF THE NEMATODE THERISTUS-ANOXYBIOTICUS FROM SUBLITTORAL MUDDY SEDIMENT AT METHANE SEEPAGES IN THE NORTHERN KATTEGAT, DENMARK
LIFE-HISTORY OF THE NEMATODE THERISTUS-ANOXYBIOTICUS FROM SUBLITTORAL MUDDY SEDIMENT AT METHANE SEEPAGES IN THE NORTHERN KATTEGAT, DENMARK
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DOI：
10.1007/bf00350331
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发表时间：
1995-07-01
期刊：
影响因子：
2.4
通讯作者：
JENSEN, P
中科院分区：
文献类型：
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作者：
JENSEN, P
1989 年至 1994 年对栖息于丹麦卡特加特北部甲烷渗漏处泥质沉积物中的线虫 Theristus (Penzancia) anoxybioticus Jensen（1995 年）进行的现场和实验室研究揭示了一系列以前在自由生活的海洋线虫中未观察到的成虫和幼虫的生物学特征。具有繁殖能力的成虫仅在四月和五月出现，栖息在沉积物的最上层，而幼虫则在一年中的剩余月份中栖息在深层缺氧和硫化物沉积层中。这表明刚孵化的幼体会向下迁移，而成年后会向上迁移。肠道内容物分析表明，成虫主要通过吞咽整个细胞以底栖硅藻为食，而幼虫可能以细菌为食；食物的这种差异显然与其各自微生境中的大部分潜在食物有关。世代时间估计为一年，幼虫寿命约为九个月，比体型相似的需氧相关物种长四到八倍。成虫在含氧水中存活，但在缺氧水中（5%至6% atm sat），50%在15小时内死亡，在缺氧水中12小时内全部死亡。另一方面，幼鱼在含氧水中 0.5 小时内死亡，但在缺氧水中存活至少 15 天。这些结果表明，T. anoxybioticus 幼体适应了厌氧生活方式。
Field and laboratory studies from 1989 to 1994 of the nematode Theristus (Penzancia) anoxybioticus Jensen, 1995 inhabiting muddy sediment at methane seepages in the northern Kattegat, Denmark, have revealed a series of biological features of adults and juveniles not observed before in free-living marine nematodes. Reproductive adults were present in April and May only and inhabited the uppermost cm of sediment, while juveniles inhabited deep anoxic and sulphidic sediment layers during the remaining months of the year. This points to a downwards migration of newly hatched juveniles and an upwards migration during adulthood. Gut content analyses showed that adults feed mainly on benthic diatoms by swallowing whole cells while juveniles probably feed on bacteria; this differentiation in food clearly relates to the main bulk of potential food items in their respective microhabitats. The generation time is estimated to be one year, with a juvenile life span of about nine months, which is four to eight times longer than that found in related aerobic species of similar body size. Adults survived in oxic water but 50% died within 15 h in hypoxic water (5 to 6% atm sat), and all died within 12 h in anoxic water. Juveniles on the other hand died within 0.5 h in oxic water but survived anoxic water for at least 15 d. These results suggest that juveniles of T. anoxybioticus are adapted to an anaerobic life style.