Tube-dwelling invertebrates: tiny ecosystem engineers have large effects in lake ecosystems
Tube-dwelling invertebrates: tiny ecosystem engineers have large effects in lake ecosystems
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DOI：
10.1890/014-1160.1
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发表时间：
2015-08-01
影响因子：
6.1
通讯作者：
Lewandowski, Joerg
中科院分区：
文献类型：
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作者：
Hoelker, Franz;Vanni, Michael J.;Lewandowski, Joerg
有充分的证据表明，摇蚊等管栖无脊椎动物显著改变了多种重要的生态系统功能，特别是在浅水湖泊中。摇蚊通过沉积物泵送大量的水以及相关的悬浮和溶解物质，从而与远洋滤食者争夺颗粒有机物。这可能会对浮游植物、微生物，也许还有小型浮游动物施加很高的放牧压力，从而加强底-上层耦合。此外，管状无脊椎动物的间歇性抽水使沉积物氧化，并创造了一种动态的、三维的氧化还原条件。这塑造了微生物群落的组成和空间分布，并改变了微生物介导的生物地球化学功能，这通常取决于氧化还原电位。因此，元素循环的扩展热点出现在氧-缺氧界面上，控制着有机质和营养物质的去向以及沉积物和水之间的营养物质通量。令人惊讶的是，这些生物体所介导的相互作用的机制和大小仍然知之甚少。为了提供管居无脊椎动物重要性的综合，我们回顾了现有的研究，并将以前被忽视的功能特征整合到一个生态系统模型中。根据已有的研究和我们的模型，我们得出结论，管居无脊椎动物在控制水柱营养库，从而控制水质和营养状态方面起着核心作用。此外，这些微小的生态系统工程师可以影响决定浅水湖泊清澈和浑浊交替状态变化的门槛。这种巨大的影响与强调主要是远洋食物网的传统湖沼学范式形成了鲜明对比。鉴于全世界有大量的浅水湖，底栖无脊椎动物很可能是区域和全球范围内生物地球化学过程的相关驱动因素，从而调节与气候变化有关的反馈机制。
There is ample evidence that tube-dwelling invertebrates such as chironomids significantly alter multiple important ecosystem functions, particularly in shallow lakes. Chironomids pump large water volumes, and associated suspended and dissolved substances, through the sediment and thereby compete with pelagic filter feeders for particulate organic matter. This can exert a high grazing pressure on phytoplankton, microorganisms, and perhaps small zooplankton and thus strengthen benthic-pelagic coupling. Furthermore, intermittent pumping by tube-dwelling invertebrates oxygenates sediments and creates a dynamic, three-dimensional mosaic of redox conditions. This shapes microbial community composition and spatial distribution, and alters microbe-mediated biogeochemical functions, which often depend on redox potential. As a result, extended hotspots of element cycling occur at the oxic-anoxic interfaces, controlling the fate of organic matter and nutrients as well as fluxes of nutrients between sediments and water. Surprisingly, the mechanisms and magnitude of interactions mediated by these organisms are still poorly understood. To provide a synthesis of the importance of tube-dwelling invertebrates, we review existing research and integrate previously disregarded functional traits into an ecosystem model. Based on existing research and our models, we conclude that tube-dwelling invertebrates play a central role in controlling water column nutrient pools, and hence water quality and trophic state. Furthermore, these tiny ecosystem engineers can influence the thresholds that determine shifts between alternate clear and turbid states of shallow lakes. The large effects stand in contrast to the conventional limnological paradigm emphasizing predominantly pelagic food webs. Given the vast number of shallow lakes worldwide, benthic invertebrates are likely to be relevant drivers of biogeochemical processes at regional and global scales, thereby mediating feedback mechanisms linked to climate change.