School of Environment, Science and Engineering, Southern Cross University, Lismore, NSW 2480, Australia.
Sci Total Environ. 2014 Jan 15;468-469:774-84. doi: 10.1016/j.scitotenv.2013.09.003. Epub 2013 Sep 25.
Climate change is impacting global surface water resources, increasing the need for a deeper understanding of the interaction between climate and biological diversity. This is particularly the case in the Southern Hemisphere sub-tropics, where little information exists on the aquatic biota response to climate variations. Palaeolimnological techniques, in particular the use of diatoms, are well established and can significantly contribute to the understanding of climatic variability and the impacts that change in climate have on aquatic ecosystems. A sediment core from Lake McKenzie, Fraser Island (Australia), was used to investigate interactions between climate influences and aquatic ecosystems. This study utilises a combination of proxies including biological (diatom), geochemical and chronological techniques to investigate long-term aquatic changes within the perched-dune lake. A combination of (210)Pb and AMS (14)C dates showed that the retrieved sediment represented a history of ca. 37,000 cal.yBP. The sedimentation rate in Lake McKenzie is very low, ranging on average from 0.11 mm to 0.26 mm per year. A sediment hiatus was observed between ca. 18,300 and 14,000 cal.yBP suggesting a period of dry conditions at the site. The diatom record shows little variability over the period of record, with benthic, freshwater acidic tolerant species dominating. Relative abundance of planktonic species and geochemical results indicates a period of increased water depth and lake productivity in the early Holocene and a gradual decrease in effective precipitation throughout the Holocene. Results from this study not only support earlier work conducted on Fraser Island using pollen reconstructions but also demonstrate that diatom community diversity has been relatively consistent throughout the Holocene and late Pleistocene with only minor cyclical fluctuation evident. This record is consistent with the few other aquatic palaeoecological records from the Southern Hemisphere sub-tropics.
气候变化正在影响着全球地表水的资源，这使得我们需要更深入地了解气候与生物多样性之间的相互作用。这种情况在南半球亚热带地区尤为明显，因为有关水生生物群对气候变化的响应的信息很少。古湖泊学技术，特别是利用硅藻，已经得到了很好的发展，并可以为了解气候变异性以及气候变化对水生生态系统的影响做出重要贡献。弗雷泽岛麦肯齐湖（澳大利亚）的一个沉积岩芯被用来研究气候影响与水生生态系统之间的相互作用。本研究利用了一系列的代理指标，包括生物（硅藻）、地球化学和年代学技术，以调查高位沙丘湖中长期的水生变化。（210）Pb 和 AMS（14）C 年代测定的组合表明，所提取的沉积物代表了大约 37000 年的历史。麦肯齐湖的沉积速率非常低，平均每年为 0.11 毫米至 0.26 毫米。在大约 18300 年至 14000 年之间观察到一个沉积间断，表明该地点有一段干燥的时期。硅藻记录在记录期间变化不大，以底栖、淡水耐酸性物种为主。浮游生物种类的相对丰度和地球化学结果表明，在全新世早期水深和湖泊生产力增加，而整个全新世有效降水量逐渐减少。本研究的结果不仅支持了早些时候在弗雷泽岛上使用花粉重建进行的工作，而且还表明，硅藻群落多样性在整个全新世和更新世晚期一直相对稳定，只有微小的周期性波动。这一记录与南半球亚热带地区其他少数几个水生古生态学记录一致。
