Carbon partitioning in a wet and a semiwet subarctic mire ecosystem based on in situ 14C pulse-labelling
Carbon partitioning in a wet and a semiwet subarctic mire ecosystem based on in situ 14C pulse-labelling
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DOI：
10.1016/j.soilbio.2010.09.034
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发表时间：
2011-02-01
影响因子：
9.7
通讯作者：
Christensen, Torben R.
中科院分区：
文献类型：
--
作者：
Olsrud, Maria;Christensen, Torben R.
在这项研究中，我们使用原位C-14脉冲标记技术对两个亚北极沼泽生态系统--湿微营养沼泽和半湿营养沼泽--中近期同化物到地上和地下碳(C)池的分配进行了量化。在三种不同土壤深度的生长季节，对生态系统C向根茎、粗根、细根、溶解有机碳(DOC)和微生物的分配进行了两次量化。最后，结合本研究和前人的研究，估算了北欧亚北极沼泽三种主要植被类型在夏初和夏末的总碳分配。半湿润营养生态系统比湿润微营养生态系统在面积上拥有更大的根生物量，这可能是由于土壤养分水平的差异。微生物C是两个生态系统中最大的碳库。在半湿和湿生态系统中，生态系统C-14分配与植物生物量相关性较差。总体而言，与6-7月相比，8-9月新近同化物向地下隔室的分配明显较高，而地上C-池的分配则相反。在半湿润生态系统中，DOC中的C-14含量是湿润生态系统的两倍，湿润生态系统中的根密度、凋落物和地上生物量是DOC中C-14恢复的重要控制因素。在半湿和湿生态系统中，植物来源的DOC分别为15.4mgCm(-2)d(-1)和12.9mgCm(-2)d(-1)。亚北极沼泽Stordalen以禾本科和矮灌木为主的植被类型在最近同化的C分配到碳库的相对数量上有所不同，分解速度慢和快。“慢速”碳库中最近固定的碳的固存能力可能会影响生态系统的碳平衡(NEE)和碳储存。因此，在研究亚北极沼泽生态系统碳动态对全球变化因素的反应时，植被变化的可能性可能是一个重要因素。(C)2010爱思唯尔有限公司。保留所有权利。
In this study we quantify the partitioning of recent assimilates to above- and below-ground carbon (C) pools in two subarctic mire ecosystems - wet minerotrophic and semiwet ombrotrophic mire - using in situ C-14 pulse-labelling. Ecosystem C partitioning to rhizomes, coarse roots, fine roots, dissolved organic carbon (DOC) and microbes were quantified twice during the growing season at three different soil depths. Finally the C-14-partitioning data from this and a previous study were combined to estimate the overall C partitioning of the three main vegetation types of a Scandinavian subarctic mire in early and late summer.The semiwet ombrotrophic ecosystem hosted a much larger root biomass on an area basis compared to the wet minerotrophic ecosystem which might be due to differences in the soil nutrient level. Microbial C was found to be the largest C-pool in both ecosystems. Ecosystem C-14 partitioning was poorly related to plant biomass for the semiwet and the wet ecosystem. Overall a higher partitioning of recent assimilates to below-ground compartments was apparent in August-September compared to June-July, while the opposite was found for the above-ground C-pools. In the semiwet ecosystem twice as much C-14 was found in DOC compared to the wet ecosystem, where root density, litter and above-ground biomass were important controls of the C-14-recovery in DOC. Plant-derived DOC was estimated to be 15.4 versus 12.9 mg C m(-2) d(-1) in the semiwet and wet ecosystem, respectively.Graminoid dominated and dwarf shrub dominated vegetation types of the subarctic mire Stordalen differ with respect to the relative amount of recently assimilated C partitioned to C-pools with "slow" versus "fast" decomposition rate. The capacity for sequestration of recently fixed C within "slow" C-pools might affect the ecosystem C balance (NEE) and C-storage. The potential for vegetation changes might therefore be an important factor to consider in studies of response of ecosystem C-dynamics to global change factors in subarctic mires. (C) 2010 Elsevier Ltd. All rights reserved.