Late Holocene temperature reconstruction from Hawes Water northwest England using chironomid analysis

使用摇蚊分析从英格兰西北部霍斯沃特重建全新世晚期温度

• 批准号: NE/J014192/1
• 负责人: Alan Bedford
• 金额: $ 6.16万
• 依托单位: Edge Hill University
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2012
• 资助国家: 英国
• 起止时间: 2012 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FJ014192%2F1
• 关键词: Late; Holocene; temperature; reconstruction; Hawes

The proposed research would use chironomid midges from the sediments of Hawes Water, a small hard water lake in northwest England, to reconstruct summer temperatures for the past 5,000 years. Chironomids are one of the most widely used proxies for temperature reconstruction as they rapidly respond to even small changes in summer air temperatures. They are ideal for palaeo studies as the larval heads preserve well in sediments and many chironomid taxa are sensitive to a particular temperature range The record would provide temperatures at a resolution of approximately 30 years and would be the first high resolution quantitative record of climate change during this period from England and the only high resolution record in the UK. Past research at Hawes Water has shown the sensitivity of the site to climate changes, particularly those induced by changes in North Atlantic circulation (Marshall et al., 2007). Temperature records are available from Hawes Water for the period from ca. 14,500 to 5,000 years before 2000 (b2k). Until recently it had been thought that during the later Holocene (5,000 b2k to present) the increasing influence on the midge assemblage of human induced changes in lake water (particularly pH, nutrient and oxygen status) may override and confuse the temperature effect, thus affecting the reconstructions and making them inaccurate (see Velle et al., 2010 for discussions). However, comparisons of chironomid inferred temperature from Speke Hall Lake in Liverpool (an enriched polluted low oxygen lake) with local instrumental records for the last 80 years demonstrate that a chironomid-based temperature inference model can produce reliable estimates of mean July air temperatures, even from a lake experiencing large changes in heavy metal and sulphur pollution and nutrient status (Lang et al., imminent submission). The project will therefore extend the Hawes Water record into this Later Holocene period to produce the first complete high resolution summer temperature record from a single archive for the UK for the last 14500 years.The research would then use the reconstructed temperatures together with an existing stable oxygen isotope record from the site to reconstruct the oxygen isotope values of the paleao lake water (ISOCHIRO method of Marshall et al., 2007) for the last 5,000 years. The isotopic value of palaeo lake water directly links to that of precipitation and that of the source water from which it was evaporated (ie the north east Atlantic) and Marshall et al (2007) have shown that changes in the oxygen isotope values of early Holocene lake waters at Hawes Water were a direct downstream response to changes in North Atlantic circulation due to meltwater influxes from pro glacial lakes in America and Fenno-scandianavia. Results from this research will indicate any changes which may have taken place in the north eastern Atlantic surface waters during the later Holocene. Detailed examination of the two new records will give insight into the drivers of late Holocene climate change. Comparison of the isotopic meteoric water record and the temperature record will indicate the extent of the influence of oceanic changes on terrestrial climate and the extent to which climate change may be attributed to other climate drivers e.g. variations in solar irradiation. Completion of the full Holocene temperature record at Hawes Water will enable time series analysis which will indicate as to whether the inherent cyclicity which has been identified within the Holocene climate in some oceanic records (Bond et al., 1997) is also visible in terrestrial climate.Please see Case for Support for full reference details.

这项拟议中的研究将使用来自英格兰西北部一个小硬水湖Hawes Water沉积物的摇蚊来重建过去5,000年的夏季温度。摇蚊是最广泛使用的温度重建代理之一，因为它们对夏季气温的微小变化都能迅速做出反应。他们是理想的古研究的幼虫头保存良好的沉积物和许多摇蚊分类是敏感的一个特定的温度范围内的记录将提供温度的分辨率约为30年，将是第一个高分辨率的定量记录气候变化在此期间从英格兰和唯一的高分辨率记录在英国。Hawes Water过去的研究表明该地点对气候变化的敏感性，特别是北大西洋环流变化引起的气候变化（马歇尔等人，2007年）。温度记录可从霍斯水为期间从ca。2000年前的14,500年至5,000年（b2 k）。直到最近，人们一直认为，在全新世晚期（5,000 b2 k至今），人类引起的湖水变化（特别是pH值，营养和氧气状态）对蠓组合的影响越来越大，可能会覆盖和混淆温度效应，从而影响重建并使其不准确（见Velle等人，2010年进行讨论）。然而，从利物浦的斯皮克霍尔湖（一个富集污染的低氧湖）推断的摇蚊温度与过去80年的当地仪器记录的比较表明，基于摇蚊的温度推断模型可以产生平均7月空气温度的可靠估计，即使是从经历重金属和硫污染和营养状态大变化的湖泊（Lang等人，即将提交）。因此，该项目将把Hawes Water的记录延伸到晚全新世时期，以从英国过去14500年的单一档案中获得第一个完整的高分辨率夏季温度记录。然后，该研究将利用重建的温度和该地点现有的稳定氧同位素记录，重建古湖水的氧同位素值（马歇尔等人的等旋法，2007年，在过去的5,000年。古湖水的同位素值与降水同位素值和蒸发源水的同位素值有着直接的联系（即东北大西洋）和马歇尔等人（2007年）已经表明，在Hawes Water的全新世早期湖泊沃茨的氧同位素值的变化是对北大西洋环流变化的直接下游响应，这是由于来自美国前冰川湖泊的融水流入造成的，芬兰-斯堪的纳维亚。这项研究的结果将表明在全新世后期东北大西洋表面沃茨可能发生的任何变化。对这两个新记录的详细研究将有助于深入了解晚全新世气候变化的驱动因素。同位素大气水记录与温度记录的比较将表明海洋变化对陆地气候的影响程度，以及气候变化在多大程度上可归因于其他气候驱动因素，如太阳辐照的变化。霍斯水完整全新世温度记录的完成将使时间序列分析成为可能，这将表明在一些海洋记录中全新世气候中确定的固有周期性是否存在（Bond等人，1997）在陆地气候中也可见。请参阅案例支持以获取完整的参考详细信息。