Population dynamics of a cavernicolous nematode community in a chemoautotrophic groundwater system
Population dynamics of a cavernicolous nematode community in a chemoautotrophic groundwater system
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DOI：
10.1002/lno.10017
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发表时间：
2015-01-01
影响因子：
4.5
通讯作者：
Traunspurger, Walter
中科院分区：
文献类型：
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作者：
Muschiol, Daniel;Giere, Olav;Traunspurger, Walter
莫维尔洞穴拥有完全孤立的地下水生态系统。尽管它缺乏任何光合自养食物的输入，但它却居住着丰富的无脊椎动物群落。化能自养微生物丛漂浮在富含硫化物和甲烷的热矿洞穴水中的表面。这些垫子主要栖息着五种食菌线虫和一种掠食性桡足类动物的密集种群。由于该生态系统的脆弱性和孤立性阻碍了对这些垫子的广泛调查，因此我们开发了一个模型系统，可以对其小型底栖动物群落进行长期研究。使用原始洞穴水（同一含水层），我们在实验室盆地中进行了实验，使我们能够模拟莫维尔洞穴不稳定的含氧和硫化条件。实验开始几周后，漂浮的微生物垫在低氧环境中生长，并很快被高度适应的生物定殖，其中包括以五种线虫（Poikilolaimus sp.、Monhystrella sp.、Panagrolaimus c.f. thienemanni、Udonchus tenuicaudatus 和 Chronogaster troglodytes）为主的小型底栖动物群落。原始垫材料样品的动物群组成是相同的。在实验室中，三个月后线虫密度达到峰值193.2 cm(-2)。通过监测一年多的线虫群落结构，我们观察到线虫类群的相对重要性发生了连续变化，其中那些快速生长和 r 选择的物种（P. c.f. thienemanni、Poikilolaimus sp.）逐渐被更多的 K 选择物种（C. troglodytes、U. tenuicaudatus）所取代。在天然垫材料的样本中也测定了类似的振荡，这显然反映了以微生物食物可用性减少为特征的循环演替。
Movile Cave harbors a completely isolated groundwater ecosystem. Although it lacks any input of photoautotrophically based food, it is inhabited by a rich invertebrate community. Chemoautotrophic microbial mats float at the surface of the thermomineral cave water, which is rich in sulfide and methane. The mats are mainly inhabited by dense populations of five bacterivorous nematode species and one predacious copepod species. As extensive investigations of these mats are hampered by the fragility and isolation of this ecosystem, we developed a model system allowing long-term studies of their meiofaunal communities. Using the original cave water (same aquifer), we carried out experiments in a laboratory basin that allowed us to simulate the labile oxic and sulfidic conditions of Movile Cave. A few weeks after the start of the experiment, floating microbial mats developed within hypoxic enclosures and were quickly colonized by highly adapted organisms, including a meiofaunal community dominated by five nematode species (Poikilolaimus sp., Monhystrella sp., Panagrolaimus c.f. thienemanni, Udonchus tenuicaudatus, and Chronogaster troglodytes). The faunal composition of samples from the original mat material was identical. In the laboratory, peak densities of 193.2 nematodes cm(-2) were reached after three months. By monitoring the nematode community structure over one year, we observed a sequential shift in the relative importance of the nematode taxa, in which those that were fast growing and r-selected (P. c.f. thienemanni, Poikilolaimus sp.) were gradually displaced by more K-selected species (C. troglodytes, U. tenuicaudatus). Similar oscillations were determined in samples of native mat material, apparently reflecting a cyclic succession characterized by decreasing microbial food availability.