Abstract Vegetated wetlands are naturally subjected to changes in their water-level and macrophyte coverage leading to high habitat heterogeneity. The opportunistic ecological strategy of many planktic algae and bacteria makes them suitable for studying adaptive mechanisms to environmental change in wetlands at different temporal and spatial scales. In this study, we assessed the response of microbial aquatic organisms to sudden changes in habitat conditions, resulting from regime shifts involving the presence/absence of a dense floating-macrophyte cover, by means of a 72 hours cross-transplant experiment using dialysis bags. Contrasting conditions imposed by the existing regime, such as light availability and dissolved oxygen concentration, accounted for the differences in phytoplankton and picoplankton compositions. Communities newly exposed to improved light and oxygen conditions exhibited a short-term (hours) response of C-strategists algae, such as small flagellated chrysophyceans. The onset of oxygen depletion and light impoverishment favoured the development of anaerobic anoxygenic photosynthetic bacteria (AnAnPB) and low-light adapted S-strategists (thin filamentous oscillatoriales) algae in few days. These results provide in-field evidence that phytoplankton and picoplankton assemblages are highly sensitive to environmental changes in a brief time scale, less than 72 hours. Thus, these microbial organisms can act as sentinels to fluctuations in vegetated wetlands, also giving a quick response to sudden changes deriving from anthropogenic practices that impact on wetlands water-level and provoke fluctuations in their floating vegetation cover.

中文翻译：

---

微生物浮游生物群落与植被湿地（自由漂浮植物与浮游植物优势）的状态变化相关的快速反应：一种实验性交叉移植方法

摘要 植被湿地自然会受到水位和大型植物覆盖率变化的影响，导致栖息地异质性高。许多浮游藻类和细菌的机会主义生态策略使其适用于研究不同时空尺度湿地环境变化的适应机制。在这项研究中，我们通过使用透析袋的 72 小时交叉移植实验，评估了微生物水生生物对栖息地条件突然变化的反应，这些变化是由涉及密集漂浮大型植物覆盖物的存在/不存在的制度转变引起的。现有制度强加的对比条件，如光可用性和溶解氧浓度，解释了浮游植物和微型浮游生物组成的差异。新近暴露于改善的光照和氧气条件下的社区表现出 C-strategists 藻类的短期（小时）反应，例如小型鞭毛金藻。在几天内，氧气消耗和光贫化的开始有利于厌氧无氧光合细菌 (AnAnPB) 和适应低光的 S 策略（细丝状振荡藻）藻类的发展。这些结果提供了现场证据，表明浮游植物和微型浮游生物组合在不到 72 小时的短时间内对环境变化高度敏感。因此，这些微生物有机体可以作为植被湿地波动的哨兵，也可以对人为活动引起的突然变化做出快速反应，这些变化影响湿地水位并引起其浮动植被覆盖的波动。