Global litter production, pools, and turnover times: Estimates from measurement data and regression models
Global litter production, pools, and turnover times: Estimates from measurement data and regression models
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DOI：
10.1029/97jd02956
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发表时间：
1997-08
影响因子：
--
通讯作者：
E. Matthews
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文献类型：
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作者：
E. Matthews
系统和兼容的数据库，以量化的组成，分布和周转时间的碳在全球垃圾的开发和评价。该研究采用了一种综合的方法，估计相关的垃圾池和通量使用各种基于数据和模型的技术。分析包括直接估计和间接，或代理，估计凋落物产量和池;稳态周转时间估计从两个。枯落物生产的指标包括净初级生产力和根系呼吸-土壤呼吸关系。除了实施一套回归模型，>1100发表的测量凋落物成分，沿着网站的特点，被整合到一个基线数据集，并用于估计凋落物生产和池。从历史上看，全球估计的凋落物产量范围从75至135 Pg dm/年;从这项研究的几个估计建议在这个范围的中间值，从90至100 Pg dm/年。估计地上凋落物产量从汇编的测量，39 Pg dm/yr，主要包括森林，林地，和林地草地;其他草地，灌木丛，和旱生群落，占0.25%的无冰陆地表面是在目前的汇编中没有代表。如果将这些生态系统包括在内，地面凋落物产量可能会高出5-10 Pg dm/年，包括地下生产在内的总量可能接近90-110 Pg dm/年。两个新的生产估计来自土壤和根呼吸的关系是93 Pg和100 Pg dm/年。这些估计数的主要优点是既考虑了地上垃圾又考虑了地下垃圾;后者很少被包括在内，可能占总产量的很大一部分。粗木质碎屑的生产可能会增加1012 Pg dm/年的细凋落物总量。全球凋落物总量先前估计为100至400 Pg dm。根据测量汇编，这里估计的细凋落物池为136 Pg dm。虽然这一部分估计包括覆盖不到一半无冰陆地表面的生态系统，但它包括森林和林地，它们拥有最大的水池。包括其余的生态系统可能会增加250 Pg，使总数增加到160 Pg dm。粗木质碎屑池估计额外的150 Pg dm。全球平均稳定状态周转时间估计从池和生产数据范围从1.4到3.4年，平均周转时间从部分森林/林地测量汇编是1.55年，周转时间为粗木质碎屑是1.13年。通过涵盖空间分布，成分，和幅度，沿着与众多的实地测量，这种综合的方法已经开始产生成分和生态系统的约束，模拟全球和区域凋落物场和NPP分配方案的生态系统模型。
Systematic and compatible databases to quantify composition, distribution, and turnover times of carbon in global litter were developed and evaluated. The study employs an integrated approach, estimating related litter pools and fluxes using a variety of data-based and model-based techniques. The analysis includes direct estimates and indirect, or proxy, estimates of litter production and pools; steady-state turnover times are estimated from the two. Proxies for litter production include net primary productivity and root respiration-soil respiration relationships. In addition to implementing a suite of regression models, >1100 published measurements of litter components, along with site characteristics, were integrated into a baseline data set and used to estimate litter production and pools. Historically, global estimates of litter production have ranged from 75 to 135 Pg dm/yr; several estimates from this study suggest values in the middle of this range, from 90 to 100 Pg dm/yr. The estimate of aboveground litter production from the compiled measurements, 39 Pg dm/yr, includes mainly forest, woodland, and wooded grassland; other grassland, shrubland, and xeromorphic communities that occupy ∼25% of the ice-free land surface are unrepresented in the present compilation. Aboveground litter production may be 5–10 Pg dm/yr higher with the inclusion of these ecosystems, and the total, including belowground production, may approach 90–110 Pg dm/year. Two novel production estimates derived from soil- and root-respiration relationships are 93 Pg and 100 Pg dm/yr. These estimates have the major advantage of accounting for both aboveground and belowground litter; the latter is rarely included and can account for a substantial fraction of total production. Production of coarse woody detritus may add ∼12 Pg dm/yr to the fine litter total. The global litter pool has previously been estimated at ∼100 to 400 Pg dm. The fine litter pool estimated here from the measurement compilation is 136 Pg dm. Although this partial estimate includes ecosystems covering just under half the ice-free land surface, it encompasses forests and woodlands which have the largest pools. Inclusion of the remaining ecosystems may add ∼25 Pg, raising the total to ∼160 Pg dm. An additional ∼150 Pg dm is estimated for the coarse woody detrital pool. Global mean steady state turnover times of litter estimated from the pool and production data range from 1.4 to 3.4 years; mean turnover time from the partial forest/woodland measurement compilation is ∼5 years, and turnover time for coarse woody detritus is ∼13 years. By encompassing spatial distribution, composition, and magnitude, along with numerous field measurements, this integrated approach has begun to yield compositional and ecosystem constraints on modeled global and regional litter fields and NPP allocation schemes in ecosystem models.