Abstract Sedimentary deposits from glacier-fed peatlands provide records of past glacier variability, but the dynamics of these peat-forming ecosystems have rarely been investigated. Through multi-proxy analyses of a 204-cm peat core, we reconstructed the ecological response of a glacier-fed peatland on subantarctic South Georgia to climate and glacier variability over the last 4300 years. A stable peatland with rapid carbon accumulations and dynamic turnovers between brown mosses and monocots persisted between 4300 and 2550 cal yr BP when the up-valley cirque glacier was small under a regional hypsithermal climate. Carbon accumulation rates showed two peak periods driven by climate warming, reaching 140 g C m−2 yr−1 at 4000–3500 cal yr BP and 70 g C m−2 yr−1 at 3200–2700 cal yr BP. Paired δ13C and δ18O data from brown moss cellulose reveal several intervals of glacial meltwater inundation that caused short-term disturbances of the peatland vegetation, indicating that glacial meltwater potentially still affected the peatland ecosystem during this warm period. Moss-dominated vegetation was disrupted and peatland carbon accumulation rates decreased to 15 g C m−2 yr−1 after around 2550 cal yr BP when a cooling-driven glacier advance shifted the erosion and meltwater regime enhancing the glacial sediment influx onto the peatland. Although this enhanced regime of meltwater disturbance has continued since this transition, the brown moss habitat was gradually re-established during the medieval climate warming between 1200 and 600 cal yr BP and then became dominant shortly after that. This re-establishment of brown mosses might have benefited from a period of increased carbon accumulation rates up to 100 g C m−2 yr−1 at 1200–900 cal yr BP that built up the organic matter matrix and stabilized the habitat. We conclude that the ecosystem dynamics of glacier-fed peatlands is strongly shaped by the interplay between regional climate and glacier activity. This study also demonstrates the potential of stable isotope analysis in studying the paleohydrology of non-Sphagnum peatlands.

中文翻译：

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冰川喂养的泥炭地对全新世晚期气候和南乔治亚亚南极冰川变化的生态响应

摘要 来自冰川喂养的泥炭地的沉积物提供了过去冰川变化的记录，但很少研究这些泥炭形成生态系统的动态。通过对 204 厘米泥炭核心的多代理分析，我们重建了过去 4300 年来亚南极南乔治亚岛冰川喂养的泥炭地对气候和冰川变化的生态响应。在 4300 到 2550 cal yr BP 之间，当在区域性低温气候下上游山谷冰斗冰川很小时，稳定的泥炭地具有快速的碳积累和棕色苔藓和单子叶植物之间的动态转换。碳积累率显示出由气候变暖驱动的两个高峰期，在 4000-3500 cal yr BP 时达到 140 g C m-2 yr-1，在 3200-2700 cal yr BP 时达到 70 g C m-2 yr-1。来自棕色苔藓纤维素的配对 δ13C 和 δ18O 数据揭示了冰川融水淹没的几个间隔，导致泥炭地植被的短期干扰，表明冰川融水在这个温暖时期仍可能影响泥炭地生态系统。在大约 2550 cal yr BP 之后，以苔藓为主的植被被破坏，泥炭地碳积累率下降到 15 g C m-2 yr-1，当时冷却驱动的冰川推进改变了侵蚀和融水状态，增强了冰川沉积物流入泥炭地。尽管这种融水干扰的增强机制自此过渡以来一直在继续，但在 1200 到 600 cal BP 之间的中世纪气候变暖期间，棕色苔藓栖息地逐渐重建，然后在此后不久成为主导。棕色苔藓的这种重建可能受益于在 1200-900 cal yr BP 期间碳积累率增加高达 100 g C m-2 yr-1 的时期，这建立了有机物质基质并稳定了栖息地。我们得出结论，冰川喂养的泥炭地的生态系统动态受到区域气候和冰川活动之间相互作用的强烈影响。该研究还证明了稳定同位素分析在研究非泥炭地泥炭地古水文学方面的潜力。