Laboratory of Wetland and Catchments Ecology in Tibetan Plateau, School of Ecology and Environment, Tibet University, Lhasa 850000, China; Center for Carbon Neutrality in the Earth's Third Pole, Tibet University, Lhasa 850000, China.
Laboratory of Marine Organism Taxonomy and Phylogeny, Qingdao Key Laboratory of Marine Biodiversity and Conservation, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China.
Sci Total Environ. 2023 Jul 1;880:163308. doi: 10.1016/j.scitotenv.2023.163308. Epub 2023 Apr 6.
Alpine wetland is a natural laboratory for studying the Earth's third polar ecosphere. Protist communities are key components of wetland ecosystems which are extremely vulnerable to environmental change. It is of great importance to study the protist community in relation to environment, which might be the key to understand the ecosystem of the alpine wetlands under global change. In this study, we investigated the composition of protist communities across the Mitika Wetland, a unique alpine wetland hosting tremendous endemic diversity. Using 18S rRNA gene high-throughput sequencing, we evaluated how protist taxonomic and functional group composition is structured by seasonal climate and environmental variation. We found a high relative abundance of Ochrophyta, Ciliophora, and Cryptophyta, each of which showcased a unique spatial pattern in the wet and dry seasons. The proportion of consumers, parasites and phototrophs groups were stable among the functional zones and also between the seasons, with consumers dominating communities in terms of richness, while phototrophic taxa dominated in terms of relative abundance. Protist and each functional group were rather regulated by deterministic than stochastic processes, with water quality having a strong control on communities. Salinity and pH were the most important environmental factors at shaping protistan community. The protist co-occurrence network dominated by the positive edge indicating the communities resisted extreme environmental conditions through close cooperation, and more consumers were determined as the keystones in wet season and more phototrophic taxa in dry season. Our results provided the baseline of the protist taxonomic and functional group composition in the highest wetland, and highlighted environmental selections drive protist distribution, implying the alpine wetland ecosystem are sensitive to climate changes and human activities.
高山湿地是研究地球第三极生态系统的天然实验室。原生生物群落是湿地生态系统的关键组成部分，而湿地生态系统对环境变化极其敏感。研究与环境有关的原生生物群落对于了解全球变化下的高山湿地生态系统至关重要。在这项研究中，我们调查了米蒂卡湿地（Mitika Wetland）的原生生物群落组成，该湿地是一个独特的高山湿地，拥有巨大的特有多样性。我们使用 18S rRNA 基因高通量测序技术，评估了原生生物分类和功能群组成如何受到季节性气候和环境变化的影响。我们发现，Ochrophyta、Ciliophora 和 Cryptophyta 的相对丰度较高，每个类群在湿地的干湿季节都表现出独特的空间模式。消费者、寄生虫和光养生物组的比例在功能区之间以及季节之间保持稳定，消费者在丰富度方面占主导地位，而光养生物类群在相对丰度方面占主导地位。原生生物和每个功能群都受到确定性过程的调节，而不是随机过程的调节，水质对群落有很强的控制作用。盐度和 pH 值是塑造原生生物群落的最重要环境因素。原生生物共现网络以正边缘为主，表明群落通过紧密合作来抵抗极端环境条件，更多的消费者在湿季被确定为关键种，而更多的光养生物类群在干季被确定为关键种。我们的研究结果为高山湿地中最高的原生生物分类和功能群组成提供了基线，并强调了环境选择驱动原生生物分布，这意味着高山湿地生态系统对气候变化和人类活动敏感。
