Department of Evolutionary Biology, Ecology and Environmental Sciences, Universitat de Barcelona, Av. Diagonal 643, 08028 Barcelona, Spain.
Department of Evolutionary Biology, Ecology and Environmental Sciences, Universitat de Barcelona, Av. Diagonal 643, 08028 Barcelona, Spain; Geosciences Barcelona (GEO3BCN), CSIC, Solé I Sabaris, S/N, 08028 Barcelona, Spain.
Sci Total Environ. 2023 Aug 1;884:163685. doi: 10.1016/j.scitotenv.2023.163685. Epub 2023 Apr 25.
In the Mediterranean region, annual mean air temperature will continue to increase during the 21st century, while seasonal precipitation is expected to decrease and extreme events to be more frequent. Human-induced climate change will severely impact aquatic ecosystems. A subdecadal stratigraphic diatom record of Lake Montcortès (central Pyrenees) was investigated, focusing on the potential responses of diatoms to anthropogenic warming and catchment alteration. The study includes the end of the Little Ice Age (LIA), the transition to the industrial and postindustrial eras, and the recent global warming and its current acceleration. Sediment samples were treated and diatoms taxonomically identified. Relationships between diatom taxa abundances and climatic (temperature and precipitation) and environmental (land use, soil erosion, and eutrophication) variables were investigated using multivariate statistical methods. The results indicate that, from ca. 1716 to 1971 CE, the diatom community was dominated by Cyclotella cyclopuncta and showed small perturbations, despite the pressure of important stressors such as strong cooling episodes, droughts and an intense use of the lake for hemp retting during the 18th and 19th centuries. However, during the 20th century, other centric species gained relevance, and from the 1970s on, Cyclotella ocellata competed with C. cyclopuncta for dominance. These changes coincided with pulse-like disturbances in the form of extreme rainfall events along with the gradual 20th century increase in global temperature. These perturbations affected the planktonic diatom community and led to instability dynamics. The benthic diatom community did not reflect any comparable shifts under the effect of the same climatic and environmental variables. Because heavy rainfall episodes are likely to intensify with current climate change in the Mediterranean region, their importance as stressors of planktonic primary producers should be taken into account as potential disrupters of biogeochemical cycles and trophic networks of lakes and ponds.
在地中海地区，21 世纪期间年平均空气温度将继续上升，而季节性降水预计将减少，极端事件将更加频繁。人为引起的气候变化将严重影响水生生态系统。本研究对来自比利牛斯山脉中心的 Montcortès 湖的亚年代地层的硅藻记录进行了研究，重点关注硅藻对人为变暖及集水区变化的潜在响应。研究包括小冰期（LIA）末期、工业和后工业化时代的转变以及最近的全球变暖及其当前的加速。对沉积物样本进行了处理，并对硅藻进行了分类鉴定。使用多元统计方法研究了硅藻丰度与气候（温度和降水）和环境（土地利用、土壤侵蚀和富营养化）变量之间的关系。结果表明，从大约 1716 年到 1971 年，尽管受到 18 世纪和 19 世纪期间的强冷却事件、干旱和大麻沤制对湖泊的强烈利用等重要胁迫的压力，但硅藻群落主要由 Cyclotella cyclopuncta 组成，并显示出较小的波动。然而，在 20 世纪，其他中心种变得更加重要，从 20 世纪 70 年代开始，Cyclotella ocellata 与 C. cyclopuncta 竞争优势地位。这些变化与 20 世纪全球温度逐渐升高同时发生的极端降雨事件引起的脉冲式干扰相一致。这些干扰影响了浮游硅藻群落，并导致了不稳定的动态。在受到相同气候和环境变量的影响下，底栖硅藻群落没有反映出任何可比的变化。由于在地中海地区，强降雨事件可能会随着当前气候变化而加剧，因此应将其作为浮游初级生产者的胁迫因素，以考虑其作为湖泊和池塘生物地球化学循环和营养网络潜在干扰物的重要性。
