Chironomid counts and loss-on-ignition for a 33cm long gravity core from lake Lontjørnane, Norway@en

This dataset provides chironomid count data and loss-on-ignition measurements for a short sediment record from lake Lontjørnane, located in the Røldal region, Norway. The core spans 33cm and dates from ca 1175 CE to the present. We obtained a sediment core from the centre of the lake (8.8 m water depth) using a HON/Kajak gravity corer during fieldwork in September 2019, and subdivided the core into 1-cm-thick samples in the field. Samples were transported to the laboratory (Birkbeck University of London, UK), where they were weighted and processed using standard protocols – this involved 20 min treatment with warm KOH (10 %) and sieving over a 100 µm mesh. Chironomid head capsules were subsequently handpicked from the residue, mounted on permanent microscope slides, and identified using Brooks et al. (2007). This dataset provides chironomid count data in number of chironomid head capsules per sample. Additionally, loss-on-ignition was determined for each sample by comparing the dry weight of the sample before and after combustion at 550 °C following Heiri et al. (2001). The chironomid dataset provides insight in centennial-scale changes in the insect community of the lake ecosystem under past climate change and current anthropogenic impact.本数据集提供了挪威勒尔达尔（Røldal）地区隆蒂约纳湖（Lake Lontjørnane）一处短沉积岩芯的摇蚊（chironomid）计数数据与烧失量（loss-on-ignition）测定结果。该岩芯总长33厘米，年代跨度约为公元1175年至今。2019年9月的野外考察中，研究团队采用HON/Kajak重力取样器，从该湖湖心（水深8.8米）采集了沉积岩芯，并在野外将岩芯分切为1厘米厚的样品。样品被运送至英国伦敦大学伯贝克学院（Birkbeck University of London）实验室，经称重后按照标准化流程处理：先用10%温热氢氧化钾（KOH）溶液浸泡处理20分钟，再过100微米（µm）筛网筛分。随后研究人员从筛余物中手工挑取摇蚊头囊，封固于永久显微镜载玻片上，并依据Brooks等人2007年的研究成果进行物种鉴定。本数据集的摇蚊计数数据以每个样品中的摇蚊头囊数量为统计单位。此外，参照Heiri等人2001年的研究方法，通过对比样品在550℃灼烧前后的干重，测定了每个样品的烧失量。本摇蚊数据集可用于揭示过去气候变化与当前人为干扰背景下，该湖泊生态系统昆虫群落的百年尺度变化特征。