Cascading effects of larval Crucian carp intro-duction on phytoplankton and microbial com-munities in a paddy field : top-down and bot-tom-up controls
Cascading effects of larval Crucian carp intro-duction on phytoplankton and microbial com-munities in a paddy field : top-down and bot-tom-up controls
复制标题
引入鲫鱼幼体对稻田浮游植物和微生物群落的级联效应：自上而下和自下而上的控制
DOI：
10.1007/s11284-011-0820-9
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发表时间：
2011
影响因子：
2
通讯作者：
M.
中科院分区：
文献类型：
--
作者：
Nishimura;Y.;Ohtsuka;T.;Yoshiyama;K.;Nakai;D.;Shibahara;F. & Maehata;M.
鱼类捕食的影响通过水生食物网传播，在水生食物网中，传统的放牧食物链和微生物环通过营养相互作用交织在一起。对水生食物网的总体影响更加复杂，因为鱼类也可能通过营养再生实施自下而上的控制。然而，关于鱼类、浮游动物、浮游植物和微生物之间的级联效应，我们仍然掌握的信息有限。在这项研究中，我们进行了一项中游实验，以评估鱼类引入对浮游生物群落的影响。在一块稻田里设置6块稻草引种和稻草耕作的析因组合，试验持续4周。鱼类的引入显著增加了较小组分(<；15μm)中的叶绿素浓度以及3-15μm组分中丝状细菌(>；5μm)和异养纳米鞭毛虫的丰度。0.8~3μm组分的微生物对引种的响应有增加的趋势，但不明显。这些结果表明，鱼类捕食的级联效应通过两条途径进行，一条是通过放牧食物链，另一条是通过微生物食物网。所有样地的浮游植物群落组成在引入鱼后1周之前都以相似的方式发生变化，此后在有鱼和不有鱼的样地之间出现分化。鱼类引进的自下而上效应表现为总叶绿素和不可食用浮游植物种类的增加。这项研究提供了一个例子，说明鱼类捕食如何调节浮游植物和微生物群落的生物量和结构。
Effects of fish predation propagate through aquatic food webs, where the classical grazing food chain and microbial loop are interwoven by trophic interactions. The overall impact on aquatic food webs is further complicated because fish may also exert bottom-up controls through nutrient regeneration. Yet, we still have limited information about cascading effects among fish, zooplankton, phytoplankton, and microbes. In this study, we performed a mesocosm experiment to evaluate effects of fish introduction on plankton communities. Six plots were set in factorial combination with fish introduction and rice straw plowing in a paddy field, and the experiment was continued for 4 weeks. Introduction of fish significantly increased chlorophyllaconcentrations in smaller size fractions (<15 μm) and abundances of filamentous bacteria (>5 μm in length) and heterotrophic nanoflagellates in 3–15 μm fraction. Microbes in 0.8–3 μm fraction showed increasing but not significant trends in response to fish introduction. These results indicate cascading effects of fish predation operating via two pathways, one through grazing food chain and the other through microbial food web. Phytoplankton community compositions shifted in similar fashion in all plots until 1 week after fish introduction, and then diverged between plots with and without fish thereafter. Bottom-up effects of fish introduction were suggested by increases of total chlorophyllaand inedible phytoplankton species in response to fish introduction. This study provides an example of how fish predation regulates biomass and structure of phytoplankton and microbial communities.