Terrestrial Holocene climate variability on the Antarctic Peninsula

南极半岛陆地全新世气候变化

• 批准号: NE/H014632/1
• 负责人: Howard Griffiths
• 金额: $ 3.92万
• 依托单位: University of Cambridge
• 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%2FH014632%2F1
• 关键词: Terrestrial; Holocene; climate; variability; Antarctic

The Antarctic continent is an important part of the Earth system, both influencing and responding to global ocean and atmospheric circulation. The ice sheet plays a major role in sea-level change and currently holds the equivalent of 70m of global sea-level rise. Monitoring change in the climate, cryosphere and biosphere of Antarctica is therefore a critical element in understanding and predicting future global change. Over the past 50 years, the climate over most of Antarctica has remained relatively stable, but the Antarctic Peninsula has experienced one of the highest rates of warming anywhere on Earth, with increases of 3oC since the 1950s, and even higher rates for winter in some locations. The rapid increase in temperature has been associated with decreased sea-ice extent, ice-shelf collapse, glacier retreat and increased ice flow rates, and changes in ecosystems on land and sea. However, the causes and context of the recent temperature changes are unclear, although it is thought that stratospheric ozone depletion and increasing greenhouse gases are both important. Current global climate models do not capture the observed changes adequately at present. A key question in understanding and attribution of Antarctic climate change is whether the recorded changes on the Peninsula are unusual compared with past natural climate variability. However, this question cannot be addressed because the instrumental records are too short and existing proxy-climate records are not suitably located to be able to trace the spatial signature of change over time. The project proposed here will exploit moss banks as a new proxy-climate archive to test three key hypotheses: 1) The recent temperature rise on the Antarctic Peninsula is unprecedented in the late Holocene. 2) The spatial pattern of variability is similar to that which occurred during previous periods of climate change. 3) Plant communities are responding to recent climate change by increases in growth rates and altered seasonal growth patterns. Moss banks are ideal deposits for reconstructing climate change over the land surface of the Antarctic Peninsula because of their location in relation to recorded temperature changes, their age, and their attributes as archives. The moss banks have accumulated peat over the past 5-6000 years at locations throughout the western Antarctic Peninsula. They are formed of only one or two species, annual growth can be traced in the surface peats and preservation of moss remains is good. We will use multi-proxy indicators of past climate (stable isotopes, measures of decay, testate amoebae and moss morphology) to reconstruct climate variability from critical locations across the observed gradient in rate of temperature change between 69o and 61o S. Although these techniques are tried and tested in more temperate regions of the world, they have not been employed in the Antarctic. We carried out pilot studies on Signy Island which show that these proxies work well for the moss banks in the Antarctic so we know that our approach will produce valuable results. Our work will also involve improving our understanding of proxy-climate relationships by a programme of surface sampling and measurement. The records will be calibrated using annually resolved records covering the period of instrumental observations. Together with records from Signy Island being produced as part of a current BAS PhD project supervised by members of the research team, emerging results from the BAS ice core at James Ross Island and some of the higher resolution ocean sediment records, our data will also provide the basis for a more complete understanding of late Holocene climate variability in the broader region, building on the BAS Past climate and Chemistry programme directed at reconstructing and understanding Holocene climate variability in the Antarctic Peninsula.

南极大陆是地球系统的重要组成部分，对全球海洋和大气环流产生影响和响应。冰盖在海平面变化中发挥着重要作用，目前相当于全球海平面上升 70m。因此，监测南极洲气候、冰冻圈和生物圈的变化是理解和预测未来全球变化的关键要素。过去 50 年来，南极洲大部分地区的气候保持相对稳定，但南极半岛是地球上升温速度最快的地区之一，自 20 世纪 50 年代以来升温速度上升了 3 摄氏度，某些地区的冬季升温速度甚至更高。气温的快速上升与海冰范围缩小、冰架崩塌、冰川退缩、冰流速增加以及陆地和海洋生态系统的变化有关。然而，尽管人们认为平流层臭氧消耗和温室气体增加都很重要，但近期温度变化的原因和背景尚不清楚。目前的全球气候模型尚未充分捕捉到观测到的变化。理解和归因南极气候变化的一个关键问题是，与过去的自然气候变化相比，记录到的半岛变化是否异常。然而，这个问题无法得到解决，因为仪器记录太短，并且现有的代理气候记录位置不合适，无法追踪随时间变化的空间特征。这里提出的项目将利用苔藓库作为新的代理气候档案来测试三个关键假设：1）最近南极半岛的气温上升在全新世晚期是前所未有的。 2）变化的空间格局与之前气候变化时期发生的变化相似。 3) 植物群落通过提高生长速度和改变季节性生长模式来应对最近的气候变化。苔藓库是重建南极半岛陆地表面气候变化的理想沉积物，因为它们的位置与记录的温度变化、年龄及其作为档案的属性有关。过去 5 至 6000 年间，南极半岛西部各地的苔藓堤岸积累了泥炭。它们仅由一两个物种组成，在表层泥炭中可以追踪到每年的生长，苔藓遗迹保存良好。我们将使用过去气候的多代理指标（稳定同位素、衰变测量、睾丸变形虫和苔藓形态）来重建南纬 69 度至 61 度之间观测到的温度变化率梯度的关键位置的气候变化。虽然这些技术在世界上更温带的地区进行了尝试和测试，但尚未在南极洲使用。我们在西格尼岛进行了试点研究，结果表明这些代理对南极洲的苔藓滩效果很好，因此我们知道我们的方法将产生有价值的结果。我们的工作还将包括通过地表采样和测量计划来提高我们对替代气候关系的理解。这些记录将使用涵盖仪器观测期间的年度解析记录进行校准。加上作为目前由研究团队成员监督的 BAS 博士项目的一部分而产生的西格尼岛记录、詹姆斯罗斯岛 BAS 冰芯的新结果以及一些更高分辨率的海洋沉积物记录，我们的数据还将为更全面地了解更广泛地区的全新世晚期气候变化提供基础，以 BAS 过去气候和化学项目为基础，旨在重建和了解南极半岛的全新世气候变化。

项目成果

Temporal separation between CO2 assimilation and growth? Experimental and theoretical evidence from the desiccation-tolerant moss Syntrichia ruralis.

二氧化碳同化和生长之间的时间间隔？

• DOI: 10.1111/nph.12114
• 发表时间: 2013
• 期刊: The New phytologist
• 作者: Royles J

Spatially coherent late Holocene Antarctic Peninsula surface air temperature variability

• DOI: 10.1130/g45347.1
• 发表时间: 2018-12-01
• 期刊: GEOLOGY
• 影响因子: 5.8
• 作者: Charman, Dan J.;Amesbury, Matthew J.;Griffiths, Howard
• 通讯作者: Griffiths, Howard

Taxonomic Implications of Morphological Complexity Within the Testate Amoeba Genus Corythion from the Antarctic Peninsula.

• DOI: 10.1016/j.protis.2017.07.006
• 发表时间: 2017-11
• 期刊: Protist
• 影响因子: 2.5
• 作者: T. Roland;M. Amesbury;D. Wilkinson;D. Charman;P. Convey;D. Hodgson;Jessica Royles;Steffen Clauß;E. Völcker

Stable isotope signals provide seasonal climatic markers for moss functional groups.

• DOI: 10.1098/rspb.2021.2470
• 发表时间: 2022-01-26
• 期刊: Proceedings. Biological sciences
• 作者: Royles J;Young S;Griffiths H
• 通讯作者: Griffiths H

Moss stable isotopes (carbon-13, oxygen-18) and testate amoebae reflect environmental inputs and microclimate along a latitudinal gradient on the Antarctic Peninsula.

• DOI: 10.1007/s00442-016-3608-3
• 发表时间: 2016-07
• 期刊: Oecologia
• 影响因子: 2.7
• 作者: Royles J;Amesbury MJ;Roland TP;Jones GD;Convey P;Griffiths H;Hodgson DA;Charman DJ
• 通讯作者: Charman DJ