Plant biomass and production and CO2 exchange in an ombrotrophic bog
Plant biomass and production and CO2 exchange in an ombrotrophic bog
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DOI：
10.1046/j.0022-0477.2001.00633.x
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发表时间：
2002-02
影响因子：
5.5
通讯作者：
T. Moore;J. Bubier;S. Frolking;P. Lafleur;N. Roulet
中科院分区：
文献类型：
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作者：
T. Moore;J. Bubier;S. Frolking;P. Lafleur;N. Roulet
1 地上生物量是在 Mer Bleue（加拿大安大略省渥太华附近的一个大型凸起的营养沼泽）的沼泽丘、沼泽洼地和贫沼地点测量的。沼泽地上部生物量平均为587 g·m−2，主要由灌木和泥炭藓组成。在贫瘠的沼泽地，平均生物量为317 g m−2，主要由莎草、草本植物和泥炭藓组成。地下水位较低的地方，维管束植物地上生物量较大，头状泥炭藓和维管叶生物量具有类似但较弱的关系。 2 沼泽丘丘处的地下生物量平均为 2400 g m−2，其中 300 g m−2 为细根（直径 < 2 mm），而洼地的地下生物量为 1400 g m−2（细根为 450 g m−2），贫沼地的地下生物量为 1200 g m−2。 3 在室内测量二氧化碳的净生态系统交换 (NEE)，并用于推导生态系统呼吸和光合作用。在高光通量（PAR为1500 µmol m−2 s−1）下，春季和夏季各站点的NEE范围为0.08至0.22 mg m−2 s−1（正值表示生态系统的吸收），但在夏末干旱期间降至–0.01至–0.13 mg m−2 s−1（即二氧化碳的释放）。 4 灌木和苔藓光合能力的文献估计值与通过沼泽足迹内涡流协方差技术确定的生物量和夏季二氧化碳吸收量（分别为 0.40 和 0.35–0.40 mg m−2 s−1）的测量值和夏季 CO2 吸收量的组合之间存在总体一致性。 5 总光合作用估计约为 530 g m−2year−1，总呼吸量为 460 g m−2year−1，DOC、DIC 和 CH4 输出量为 10 g m−2year−1，年碳固存率为 60g m−2year−1。根的产生和分解是沼泽碳预算的重要组成部分。根碳产量估计为 161–176 g m−2year−1，导致总根和细根的部分周转率分别为 0.2 和 1year−1。
1 Above‐ground biomass was measured at bog hummock, bog hollow and poor‐fen sites in Mer Bleue, a large, raised ombrotrophic bog near Ottawa, Ont., Canada. The average above‐ground biomass was 587 g m−2 in the bog, composed mainly of shrubs and Sphagnum capitula. In the poor fen, the average biomass was 317 g m−2, comprising mainly sedges and herbs and Sphagnum capitula. Vascular plant above‐ground biomass was greater where the water table was lower, with a similar but weaker relationship for Sphagnum capitula and vascular leaf biomass. 2 Below‐ground biomass averaged 2400 g m−2 at the bog hummock site, of which 300 g m−2 was fine roots (< 2 mm diameter), compared with 1400 g m−2 in hollows (fine roots 450 g m−2) and 1200 g m−2 at the poor‐fen site. 3 Net Ecosystem Exchange (NEE) of CO2 was measured in chambers and used to derive ecosystem respiration and photosynthesis. Under high light flux (PAR of 1500 µmol m−2 s−1), NEE ranged across sites from 0.08 to 0.22 mg m−2 s−1 (a positive value indicates ecosystem uptake) in the spring and summer, but fell to –0.01 to –0.13 mg m−2 s−1 (i.e. a release of CO2) during a late‐summer dry period. 4 There was a general agreement between a combination of literature estimates of photosynthetic capacity for shrubs and mosses and measured biomass and summer‐time CO2 uptake determined by the eddy covariance technique within a bog footprint (0.40 and 0.35–0.40 mg m−2 s−1, respectively). 5 Gross photosynthesis was estimated to be about 530 g m−2 year−1, total respiration 460 g m−2 year−1, and export of DOC, DIC and CH4 10 g m−2 year−1, leaving an annual C sequestration rate of 60 g m−2 year−1. Root production and decomposition are important parts of the C budget of the bog. Root C production was estimated to be 161–176 g m−2 year−1, resulting in fractional turnover rates of 0.2 and 1 year−1 for total and fine roots, respectively.