Weithoff Guntram, Bell Elanor M
Department Ecology and Ecosystem Modelling, University of Potsdam, 14469 Potsdam, Germany.
Berlin-Brandenburg Institute of Biodiversity Research, 14195 Berlin, Germany.
Microorganisms. 2022 Jul 2;10(7):1340. doi: 10.3390/microorganisms10071340.
Extreme habitats often harbor specific communities that differ substantially from non-extreme habitats. In many cases, these communities are characterized by archaea, bacteria and protists, whereas the number of species of metazoa and higher plants is relatively low. In extremely acidic habitats, mostly prokaryotes and protists thrive, and only very few metazoa thrive, for example, rotifers. Since many studies have investigated the physiology and ecology of individual species, there is still a gap in research on direct, trophic interactions among extremophiles. To fill this gap, we experimentally studied the trophic interactions between a predatory protist (, Heliozoa) and its prey, the rotifers and sp., the ciliate sp. and the mixotrophic protist (a green phytoflagellate, Chlorophyta). We found substantial predation pressure on all animal prey. High densities of reduced the predation impact on the rotifers by interfering with the feeding behaviour of . These trophic relations represent a natural case of intraguild predation, with being the common prey and the rotifers/ciliate and being the intraguild prey and predator, respectively. We further studied this intraguild predation along a resource gradient using sp. as the intraguild prey. The interactions among the three species led to an increase in relative rotifer abundance with increasing resource () densities. By applying a series of laboratory experiments, we revealed the complexity of trophic interactions within a natural extremophilic community.
极端生境往往蕴藏着与非极端生境有很大差异的特定群落。在许多情况下，这些群落的特征是古菌、细菌和原生生物，而后生动物和高等植物的物种数量相对较少。在极端酸性生境中，主要是原核生物和原生生物蓬勃生长，只有极少数后生动物能够生存，例如轮虫。由于许多研究已经调查了单个物种的生理学和生态学，因此在嗜极生物之间直接的营养相互作用研究方面仍然存在空白。为了填补这一空白，我们通过实验研究了一种捕食性原生生物（太阳虫）与其猎物之间的营养相互作用，猎物包括轮虫、 种、纤毛虫 种和兼养型原生生物（一种绿色植鞭毛虫，绿藻门）。我们发现对所有动物猎物都存在巨大的捕食压力。高密度的 通过干扰 的摄食行为降低了对轮虫的捕食影响。这些营养关系代表了一种 guild内捕食的自然情况，其中 是常见猎物，轮虫/纤毛虫和 分别是guild内猎物和捕食者。我们进一步以 种作为guild内猎物，沿着资源梯度研究了这种guild内捕食。这三个物种之间的相互作用导致随着资源（）密度的增加，轮虫的相对丰度增加。通过一系列实验室实验，我们揭示了自然嗜极生物群落内营养相互作用的复杂性。
