Limnological and nearshore diatom communities of Macquarie Island: proxies of subantarctic climate change?

Metadata record for data from ASAC Project 2663See the link below for public details on this project.Public SummaryMacquarie Island offers scientists a unique laboratory for investigating subantarctic climate change. We will establish the biodiversity of microalgal flora (specifically diatoms) within the lakes and lagoons of Macquarie Island and ultimately use the flora of today to investigate changes in fossil microalgal communities of Macquarie Island lake and lagoon ecosystems to better understand past, present and future climate change in the Australian Subantarctic.Taken from the abstract of the referenced paper:This study is the first established survey of diatom-environment relationships on sub-Antarctic Macquarie Island. Fifty-eight sites in 50 coastal and inland lakes were sampled for benthic diatoms and water chemistry. 208 diatom species from 34 genera were identified. Multivariate analyses indicated that the lakes were distributed along nutrient and conductivity gradients. Conductivity, pH, phosphate (SRP), functions provide a quantitative basis for palaeolimnological studies of past climate change and human impacts, and can be used to establish baseline conditions for assessing the impacts of recent climate change and the introduction of non-native plants and animals. Statistically robust diatom transfer functions for conductivity, phosphate and silicate were developed, while pH and temperature transfer functions performed less well. The lower predictive abilities of the pH and temperature transfer functions probably reflect the broad pH tolerance range of diatoms on Macquarie Island and uneven distribution of lakes along the temperature gradient. This study contributes to understanding the current ecological distribution of Macquarie Island diatoms and provides transfer functions that will be applied in studies of diatoms in lake sediment cores to quantitatively reconstruct past environmental changes.

ASAC项目2663号数据集元数据记录。点击下方链接查看该项目的公开详情。
项目公开摘要：
麦夸里岛为科研人员提供了研究亚南极气候变化的独特实验场地。本项目将对麦夸里岛各湖泊与潟湖内的微藻区系（尤其是硅藻（diatoms））开展生物多样性普查，并最终利用现存微藻区系，研究麦夸里岛湖泊与潟湖生态系统中的化石微藻群落变化，以更深入地理解澳大利亚亚南极区域过去、当前及未来的气候变化。
以下内容节选自相关论文的摘要：
本研究是亚南极麦夸里岛首个针对硅藻与环境关联的系统性调查。研究人员对50个沿海及内陆湖泊中的58个采样点开展了底栖硅藻（benthic diatoms）与水体化学性质采样，共鉴定出34个属的208种硅藻。多元分析结果显示，所有湖泊沿营养盐与电导率梯度分布。
电导率、pH值、磷酸盐（SRP）相关的硅藻转换函数，为古湖沼学（palaeolimnology）领域探究过去气候变化与人类活动影响提供了定量基础，同时可用于确立基准条件，以评估近期气候变化以及外来动植物引入所造成的影响。研究构建了针对电导率、磷酸盐与硅酸盐的统计学稳健型硅藻转换函数，而针对pH值与温度的转换函数表现相对欠佳。
pH值与温度转换函数的预测能力较低，这或许反映了麦夸里岛硅藻对pH值的耐受范围较广，且湖泊沿温度梯度的分布并不均匀。本研究有助于明确麦夸里岛硅藻当前的生态分布特征，并提供了可应用于湖泊沉积物岩芯硅藻研究的转换函数，以定量重建过去的环境变化。