Rwenzori Mountains National Park, which straddles the border between the Democratic Republic of Congo and Uganda, has experienced rapid glacier loss since the beginning of the twentieth century, yet there has been little investigation of aquatic biodiversity change in the park. This study presents a paleolimnological analysis from Lake Mahoma (2990 m asl), which is situated in the bamboo-forest transition zone. Diatom and organic geochemistry data from a 39-cm-long sediment core with a basal age of c. 1715 CE were compared with new analyses of previously published data from Lakes Bujuku (3891 m asl) and Lower Kitandara (3989 m asl), in the alpine zone. Comparisons were made to determine if aquatic ecosystem changes exhibited similar inter-lake patterns over the past ~ 150 years of climate warming and glacial recession, or if only local change was apparent. The diatom flora of Lake Mahoma is acidophilous, dominated by Aulacoseira ikapoënsis since at least the mid eighteenth century. In recent decades, the obligate nitrogen-heterotroph Nitzschia palea increased in importance, concurrent with declining δ15Norg values. We suggest that these late twentieth century changes were linked to regional warming and increased thermal stratification of Lake Mahoma. Regional comparisons of the Rwenzori lakes were done using existing organic geochemistry records (total organic carbon, C/N and δ13Corg) and through diatom compositional turnover analyses, and categorisation of species into one of four diatom growth morphology traits, or guilds: tychoplanktonic, high-profile, low-profile and motile. Over the past 150 years, all three lakes showed unidirectional, compositional diatom turnover, indicating that deterministic processes had affected diatom communities. Declining turnover at each site is broadly mirrored by an increase in tychoplanktonic taxa, along with concomitant declines in high-profile diatoms at Lake Mahoma, and low-profile diatoms at Lake Bujuku, and at least for the past 60 years, at Lower Kitandara. The interplay between diatom guilds at all sites is mainly a consequence of competition for available resources. Sediment organic carbon at all sites comes from both autochthonous and allochthonous sources, the relative abundances of which are influenced by the time elapsed since lakes had glaciers in their catchment.

中文翻译：

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中非鲁文佐里山国家公园热带山地湖泊近期气候驱动的生态变化

横跨刚果民主共和国和乌干达边界的鲁文佐里山国家公园自 20 世纪初以来经历了快速的冰川流失，但对公园内水生生物多样性变化的调查却很少。本研究对位于竹林过渡带的 Mahoma 湖（海拔 2990 米）进行了古湖泊学分析。来自基础年龄为 c 的 39 厘米长沉积岩芯的硅藻和有机地球化学数据。将公元 1715 年与之前发布的来自高山地区布宿湖湖（3891 米）和下基坦达拉（3989 米）的数据的新分析进行了比较。进行了比较以确定在过去约 150 年的气候变暖和冰川衰退中，水生生态系统的变化是否表现出类似的湖间模式，或者如果只有局部变化是明显的。马霍马湖的硅藻群是嗜酸的，至少从 18 世纪中叶开始就以 Aulacoseira ikapoënsis 为主。近几十年来，专性氮异养 Nitzschia palea 的重要性增加，同时 δ15Norg 值下降。我们认为，这些 20 世纪后期的变化与区域变暖和马霍马湖的热分层增加有关。鲁文佐里湖的区域比较是使用现有的有机地球化学记录（总有机碳、C/N 和 δ13Corg）并通过硅藻成分周转分析以及将物种归类为四种硅藻生长形态特征之一或类群：浮游、高-轮廓，低调和运动。150年来，三个湖泊都呈现单向、组成硅藻周转率，表明确定性过程影响了硅藻群落。每个地点的周转率下降大致反映为浮游生物类群的增加，同时马霍马湖的高规格硅藻和布宿湖的低规格硅藻减少，至少在过去的 60 年中，在下基坦达拉。所有站点的硅藻行会之间的相互作用主要是对可用资源的竞争的结果。所有地点的沉积物有机碳都来自本土和外来来源，它们的相对丰度受到自湖泊流域有冰川以来所流逝的时间的影响。伴随着 Mahoma 湖高规格硅藻和 Bujuku 湖低规格硅藻的减少，至少在过去 60 年中，Lower Kitandara 也是如此。所有站点的硅藻行会之间的相互作用主要是对可用资源的竞争的结果。所有地点的沉积物有机碳都来自本土和外来来源，它们的相对丰度受到自湖泊流域有冰川以来所流逝的时间的影响。伴随着 Mahoma 湖高规格硅藻和 Bujuku 湖低规格硅藻的减少，至少在过去 60 年中，Lower Kitandara 也是如此。所有站点的硅藻行会之间的相互作用主要是对可用资源的竞争的结果。所有地点的沉积物有机碳都来自本土和外来来源，它们的相对丰度受到自湖泊流域有冰川以来所流逝的时间的影响。