Carbon dioxide balance of a tropical peat swamp forest in Kalimantan, Indonesia
Carbon dioxide balance of a tropical peat swamp forest in Kalimantan, Indonesia
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DOI：
10.1111/j.1365-2486.2006.01301.x
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发表时间：
2007-02-01
影响因子：
11.6
通讯作者：
Osaki, Mitsuru
中科院分区：
文献类型：
--
作者：
Hirano, Takashi;Segah, Hendrik;Osaki, Mitsuru
热带泥炭地与沼泽森林共存，作为土壤有机质积累了大量的碳。然而，自20世纪70年代以来，森林砍伐和排水在大规模地进行。此外，厄尔尼诺与南方涛动（ENSO）干旱以及在干旱条件下规模更大的大规模火灾，正在加速泥炭地的破坏。这种破坏加剧了土壤有机质的分解，并增加了以二氧化碳形式向大气释放的碳量。这一现象表明热带泥炭地已经成为一个巨大的二氧化碳源，但相关的定量信息有限。因此，我们利用2002年至2004年通过涡度协方差技术测量的3年二氧化碳通量，评估了印度尼西亚中加里曼丹的一个热带泥炭沼泽森林的二氧化碳平衡。该森林受到排水的干扰，因此地下水位（GL）下降。生态系统净二氧化碳生产（NEP）测量显示出季节性变化，在旱季初期略为正值或几乎为零，在旱季后期或雨季初期为极负值。这种季节性可归因于气候、树木物候和火灾的季节性模式。在高光量子通量密度（PPFD）和大叶面积指数（LAI）条件下，较小的生态系统呼吸（RE）和较大的总初级生产力（GPP）导致了略为正值的NEP。极负值的NEP是由较小的GPP和较大的RE导致的。较小的GPP与高水汽压亏缺（VPD）、小LAI以及因火灾烟雾导致的低PPFD有关。较大的RE与低GL有关。2002年、2003年和2004年的年NEP值分别估计为 -602、-382和 -313克碳/平方米·年。这些负的NEP值表明，受排水干扰的热带泥炭沼泽森林起到了二氧化碳源的作用。该源强度在2002年（一个ENSO年）最高，主要是因为大火产生的浓烟导致PPFD较低。
Tropical peatlands, which coexist with swamp forests, have accumulated vast amounts of carbon as soil organic matter. Since the 1970s, however, deforestation and drainage have progressed on an enormous scale. In addition, El Nino and Southern Oscillation (ENSO) drought and large-scale fires, which grow larger under the drought condition, are accelerating peatland devastation. That devastation enhances decomposition of soil organic matter and increases the carbon release to the atmosphere as CO2. This phenomenon suggests that tropical peatlands have already become a large CO2 source, but related quantitative information is limited. Therefore, we evaluated the CO2 balance of a tropical peat swamp forest in Central Kalimantan, Indonesia, using 3 years of CO2 fluxes measured using the eddy covariance technique from 2002 through 2004. The forest was disturbed by drainage; consequently, groundwater level (GL) was reduced. The net ecosystem CO2 production (NEP) measurements showed seasonal variation, which was slightly positive or almost zero in the early dry season, and most-negative late in the dry season or early the rainy season. This seasonality is attributable to the seasonal pattern of climate, tree phenology and fires. Slightly positive NEP resulted from smaller ecosystem respiration (RE) and larger gross primary production (GPP) under conditions of high photosynthetic photon flux density (PPFD) and large leaf area index (LAI). The most-negative NEP resulted from smaller GPP and larger RE. The smaller GPP was related to high vapor pressure deficit (VPD), small LAI and low PPFD because of smoke from fires. The larger RE was related to low GL. Annual NEP values were estimated respectively as -602, -382 and -313 g C m(-2) yr(-1) for 2002, 2003 and 2004. These negative NEP values show that the tropical peat swamp forest, disturbed by drainage, functioned as a CO2 source. That source intensity was highest in 2002, an ENSO year, mainly because of low PPFD caused by dense smoke emitted from large fires.