Gulin Vesna, Vlaičević Barbara, Sertić Perić Mirela, Rebrina Fran, Matoničkin Kepčija Renata
Department of Biology, Faculty of Science, University of Zagreb, Zagreb, Croatia.
Department of Biology, Josip Juraj Strossmayer University of Osijek, Osijek, Croatia.
Front Microbiol. 2022 Apr 1;13:842395. doi: 10.3389/fmicb.2022.842395. eCollection 2022.
Tufa-depositing streams provide great microhabitat complexity and are therefore inhabited by various periphytic phagotrophic organisms such as ciliates and amoeboid protists. Recent removal of invasive plant species (Mill.) Swinge from the Skradinski buk tufa barrier (Krka National Park, Croatia) resulted in changes in the barrier hydromorphology including the reactivation (revitalization) of dry streams. The objective of this study was to investigate: (1) the taxonomic and functional response of periphytic ciliates and amoeboid protists to stream revitalization by comparing taxonomic (i.e., abundance, species richness and diversity) and functional (i.e., functional diversity) metrics between revitalized (N) and control sites (C) during 1 and 2-months immersion period; (2) which environmental and (3) periphyton-associated factors shape the taxonomic and functional metrics and to what extent; (4) how duration of immersion affects taxonomic and functional metrics at revitalized sites. Our results showed that taxonomic and functional metrics of ciliates and amoeboid protists responded to the prevailing conditions characteristic of revitalized tufa-depositing streams: changing hydrology (occasional high flow or drought), soil drainage, and extensive inorganic matter, i.e., tufa deposition, although their responses were somewhat different. The two assemblages also showed different responses of taxonomic and functional metrics with respect to immersion duration: while the taxonomic and functional diversity of ciliates at N sites increased with longer immersion, indicating niche diversification, those of amoeboid protists hardly changed with time. Our results suggest that a comprehensive analysis of taxonomic and functional metrics of ciliates and amoeboid protists could be a good proxy for assessing revitalization of tufa-depositing streams. However, the temporal component should always be considered when conducting such studies, as the colonization processes of ciliates and amoeboid protists are quite complex, especially in tufa-depositing streams.
形成钙华的溪流具有高度复杂的微生境，因此栖息着各种附生吞噬生物，如纤毛虫和变形虫类原生生物。近期，从（克罗地亚克尔卡国家公园的）斯克拉迪尼布克钙华屏障中清除入侵植物物种（米尔.）斯温格后，屏障的水文形态发生了变化，包括干涸溪流的重新激活（复苏）。本研究的目的是调查：（1）通过比较复苏（N）和对照地点（C）在1个月和2个月浸泡期内的分类学（即丰度、物种丰富度和多样性）和功能（即功能多样性）指标，研究附生纤毛虫和变形虫类原生生物对溪流复苏的分类学和功能响应；（2）哪些环境因素以及（3）与周丛生物相关的因素塑造了分类学和功能指标，以及影响程度如何；（4）浸泡持续时间如何影响复苏地点的分类学和功能指标。我们的结果表明，纤毛虫和变形虫类原生生物的分类学和功能指标对复苏的钙华沉积溪流的主要特征条件做出了响应：水文变化（偶尔的高流量或干旱）、土壤排水以及大量无机物质，即钙华沉积，尽管它们的响应略有不同。这两个类群在分类学和功能指标方面对浸泡持续时间也表现出不同的响应：虽然N地点纤毛虫的分类学和功能多样性随着浸泡时间延长而增加，表明生态位多样化，但变形虫类原生生物的分类学和功能多样性几乎不随时间变化。我们的结果表明，对纤毛虫和变形虫类原生生物的分类学和功能指标进行综合分析，可能是评估钙华沉积溪流复苏情况的良好指标。然而，在进行此类研究时应始终考虑时间因素，因为纤毛虫和变形虫类原生生物的定殖过程相当复杂，尤其是在钙华沉积溪流中。
