Laboratory of Chrono-Environment UMR-CNRS 6249, University of Franche-Comté, 25211 Montbéliard cedex, France,
Microb Ecol. 2011 Feb;61(2):374-85. doi: 10.1007/s00248-010-9756-9. Epub 2010 Oct 12.
The ecology of peatland testate amoebae is well studied along broad gradient from very wet (pool) to dry (hummock) micro-sites where testate amoebae are often found to respond primarily to the depth to water table (DWT). Much less is known on their responses to finer-scale gradients, and nothing is known of their possible response to phenolic compounds, which play a key role in carbon storage in peatlands. We studied the vertical (0-3, 3-6, and 6-9 cm sampling depths) micro-distribution patterns of testate amoebae in the same microhabitat (Sphagnum fallax lawn) along a narrow ecological gradient between a poor fen with an almost flat and homogeneous Sphagnum carpet (fen) and a "young bog" (bog) with more marked micro-topography and mosaic of poor fen and bog vegetation. We analyzed the relationships between the testate amoeba data and three sets of variables (1) "chemical" (pH, Eh potential, and conductivity), (2) "physical" (water temperature, altitude, i.e., Sphagnum mat micro-topography, and DWT), and (3) phenolic compounds in/from Sphagnum (water-soluble and primarily bound phenolics) as well as the habitat (fen/bog) and the sampling depth. Testate amoeba Shannon H' diversity, equitability J of communities, and total density peaked in lower parts of Sphagnum, but the patterns differed between the fen and bog micro-sites. Redundancy analyses revealed that testate amoeba communities differed significantly in relation to Eh, conductivity, water temperature, altitude, water-soluble phenolics, habitat, and sampling depth, but not to DWT, pH, or primarily bound phenolics. The sensitivity of testate amoebae to weak environmental gradients makes them particularly good integrators of micro-environmental variations and has implications for their use in paleoecology and environmental monitoring. The correlation between testate amoeba communities and the concentration of water-soluble phenolic suggests direct (e.g., physiological) and/or indirect (e.g., through impact on prey organisms) effects on testate amoebae, which requires further research.
湿地藻类生态研究广泛，涵盖从非常湿润（池塘）到干燥（丘）的微生境，这些微生境中通常发现藻类主要对水位深度（DWT）做出响应。关于它们对更细微尺度梯度的响应知之甚少，对于酚类化合物可能的反应则一无所知，而酚类化合物在泥炭地的碳存储中起着关键作用。我们研究了在同一微生境（Sphagnum fallax 草坪）中，在贫泥炭湿地（几乎是平坦且均匀的 Sphagnum 地毯，fen）和“年轻沼泽”（bog）之间狭窄的生态梯度上，垂直（0-3、3-6 和 6-9 cm 采样深度）的藻类分布模式。我们分析了藻类数据与三组变量（1）“化学”（pH、Eh 潜力和电导率）、（2）“物理”（水温、海拔，即 Sphagnum 垫微地形和水位深度）和（3）来自 Sphagnum 的酚类化合物（水溶性和主要结合酚）以及栖息地（fen/bog）和采样深度之间的关系。藻类的 Shannon H'多样性、群落均匀度 J 和总密度在 Sphagnum 的下部达到峰值，但在 fen 和 bog 微生境之间存在差异。冗余分析表明，藻类群落与 Eh、电导率、水温、海拔、水溶性酚类、栖息地和采样深度显著不同，但与 DWT、pH 或主要结合酚类无关。藻类对弱环境梯度的敏感性使其成为微环境变化的特别好的综合指标，并对其在古生态学和环境监测中的应用具有重要意义。藻类群落与水溶性酚类浓度之间的相关性表明对藻类有直接（例如，生理）和/或间接（例如，通过对猎物生物的影响）的影响，这需要进一步研究。
