Microbial Food Webs in Marine Sediments. II. Seasonal Changes in Trophic Interactions in a Sandy Tidal Flat Community
Microbial Food Webs in Marine Sediments. II. Seasonal Changes in Trophic Interactions in a Sandy Tidal Flat Community
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DOI：
10.1007/s002489900049
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发表时间：
1997-11
影响因子：
3.6
通讯作者：
S. Epstein
中科院分区：
文献类型：
--
作者：
S. Epstein
摘要研究了海洋沉积物鞭毛虫、纤毛虫和小型底栖动物的放牧在控制其细菌和硅藻猎物生产中的作用。在一年中的六个选定时间点，将细菌产量和硅藻存量与原生动物和微型后生动物消费者施加的放牧压力进行比较。猎物与捕食者关系的强度显示出明显的年度动态，其中可以区分两个阶段。第一阶段，冬末至盛夏，硅藻消耗量逐渐增加，后期可能出现过度放牧。随后硅藻丰度锐减至冬季水平。在第一阶段，尽管细菌丰度和产量很高，但没有观察到明显的细菌消耗。第二阶段从仲夏开始，一直持续到秋季。在此期间，细菌的放牧量增加并达到年内的最大值。至少在很短的一段时间内（十月），小食草动物消除了大部分细菌的产生。相比之下，食草动物数量保持在今年的最低水平，硅藻数量似乎受到放牧以外因素的控制。观察到的摄入率似乎支持鞭毛虫和一些纤毛虫（盾纤毛虫和短毛虫）的表观能量需求。其他纤毛虫（侧口虫和核虫）无法依靠观察到的饮食生存，可能必须通过吸收溶解的有机物来补充其他能量来源。
AbstractThe role of grazing by marine sediment flagellates, ciliates, and meiobenthic animals in controlling production of their bacterial and diatom prey was investigated. At six selected time points, over the year, bacterial production and diatom standing stock were compared to grazing pressure exercised by proto- and micrometazoan consumers. The intensity of prey-predator relations showed pronounced yearly dynamics in which two stages could be distinguished. During the first phase, from the end of winter to mid-summer, the consumption of diatoms gradually increased, with possible overgrazing at the end of the period. This was followed by a collapse of diatom abundance, to the winter level. During the first stage, no appreciable bacterial consumption was observed in spite of the high abundance and production of bacteria. The second stage started in mid-summer and continued through the fall. During this period, the grazing on bacteria increased and reached the year's maximum. For at least a brief period (October), micrograzers removed the majority of bacterial production. In contrast, herbivory stayed at the year's lowest level, and diatoms appeared to be controlled by factors other than grazing. The observed ingestion rates seem to support the apparent energy requirements of flagellates and some ciliates (scuticociliates and hypotrichids). Other ciliates (pleurostomatids and karyorelictids) could not subsist on the observed diet and might have to complement it with other energy sources, possibly via dissolved organic matter absorption.