The consequences of the Little Ice Age period over peat sequestration in northern peatlands

在这个5年的建议中提出的研究计划遵循我在整个全新世期间进行的研究活动，提供原始数据的泥炭启动，泥炭地的发展和相关的碳积累从加拿大东北部北方生物群落的不同生态区。我们的研究结果提出了区域的空间和时间全新世C积累沿着与不同的季节模式，并确认长期气候变化的作用，泥炭地动态和相关的C封存的重要驱动力。在国际社会，最近已采取行动，以加强对泥炭积累的关键气候时期的理解，如新冰期（3000 BP），中世纪气候异常（350-1200 BP）和小冰期（LIA）（1350-1850 AD）。在北方国家，LIA代表了一个关键时期，因为它在过去几个世纪中影响了永久冻土的沉积。如今，在北方针叶林和针叶林的最北方地区仍有一些残留的永久冻土，而景观其他部分的地貌指数表明其最近融化。详细重建的发病最近的寒冷异常时期，其对泥炭积累的影响和最近的消失，最近变暖的影响，将被用来作为类似物，记录在加拿大东北部的现今北极变暖的后果。我们打算记录外部强迫的影响，如北大西洋涛动（NAO）的变化，太阳辐射和/或火山活动已被确定为这种冷却的主要原因。方法，如宏体化石，有壳变形虫，腐殖化和同位素分析加上精确的测年年表（14 C和210 Pb）和年龄模型将支持详细重建这一时期的特点是寒冷的气候扰动和随后的变暖。改进方法的结果也将被纳入国际努力（欧洲、美国、加拿大其他地区），以合并各种泥炭数据库，并开发对响应IPPC报告的PMIP（古气候模拟相互比较项目）和PCMIP（古碳模拟相互比较项目）模拟社区有用的输出。

The research program presented in this 5-years proposal follows my precedent research activities conducted over the entire Holocene period providing original data on peat initiation, peatland development and related C accumulation from different ecoregions of the northeastern canadian boreal biome. Our results present regional spatial and temporal Holocene C accumulation along with distinct seasonal patterns and confirm the role of long-term climate variations as an important driver in peatland dynamics and related C sequestration. In the international community, recent initiatives have been taken up to enhance the understanding of critical climate periods on peat accumulation such as the Neoglacial period (3000 BP), the Medieval Climate Anomaly (350-1200 BP) and the Little Ice Age (LIA) (1350-1850 AD). In northern countries, the LIA represents a critical period as it has influenced permafrost aggradation over the past centuries. Nowadays, some relict permafrost remains in the most northern regions of the open boreal forest and in the taiga while geomorphic indices in some other part of the landscape suggests its recent melting. The detailed reconstruction of the onset of this recent cold anomaly period, its impact over peat accumulation and its recent disappearance influenced by the recent warming will be used as analogs to document the consequences of the present-day arctic warming in northeastern Canada. We intend to document the impacts of external forcings such as the variations in the North Atlantic Oscillation (NAO), solar radiation and/or volcanic activities that have been identified as principal causes of this cooling. Methods such as macrofossils, testate amoebae, humification and isotopic analyses coupled with precise dating chronologies (14C and 210Pb) and age models will support the detailed reconstructions of this period characterized by cold climate disturbance and subsequent warming. Results of improved methods will also be integrated into international efforts (Europe, United, other parts of Canada) for amalgamation of various peat databases and development of outputs that will be useful for the PMIP (Paleoclimate Modelling Intercomparison Project) and PCMIP (Paleocarbon Modelling Intercomparison Project) modellers community that respond to the IPPC reports.