Heterotrophic and Autotrophic Soil Respiration under Simulated Dormancy Conditions
Heterotrophic and Autotrophic Soil Respiration under Simulated Dormancy Conditions
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模拟休眠条件下的异养和自养土壤呼吸
DOI：
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发表时间：
2015
期刊：
影响因子：
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通讯作者：
S. Franklin
中科院分区：
文献类型：
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作者：
Daniel Beverly;S. Franklin
在过去的20年里，碳循环研究有所增加，但对休眠条件下土壤呼吸的主要贡献者（即异养和自养）知之甚少。据了解，土壤CO2排放量显着较低，在冬季的温带生态系统和假定微生物占主导地位的排放起源。我们假设，异养的贡献将大于自养模拟休眠条件下。为了验证这一假设，我们设计了一个实验，以下处理：联合自养异养呼吸，异养呼吸，自养呼吸，无呼吸，蛭石中的自养呼吸，蛭石中的无呼吸。将Engelmann云杉幼苗和土壤基质置于专门设计的呼吸室中，并在一个月内进行了四次土壤CO2排放测量。在第三十三天之后，测量每个室的土壤微生物密度和根体积。幼苗的存在导致显着更高的土壤CO2排放速率为所有土壤基质。自养呼吸处理不代表单独的自养土壤CO2排放由于土壤微生物污染的高压灭菌土壤基质，然而，平均自养贡献平均小于25%的总土壤CO2排放。土壤微生物群落可能是模拟休眠条件下土壤CO2排放的主要贡献者，因为微生物密度比例最大的处理具有最高的土壤CO2排放率。虽然这项研究是不直接可比的领域休眠季节土壤CO2排放的恩格尔曼云杉林，积雪不保持在整个实验中，关系，并从这种小规模的生态系统组件过程的指标可能会产生更准确的碳预算模型。
Carbon cycling research has increased over the past 20 years, but less is known about the primary contributors to soil respiration (i.e. heterotrophic and autotrophic) under dormant conditions. It is understood that soil CO2 effluxes are significantly lower during the winter of temperate ecosystems and assumed microorganisms dominate efflux origination. We hypothesized that heterotrophic contributions would be greater than autotrophic under simulated dormancy conditions. To test this hypothesis, we designed an experiment with the following treatments: combined autotrophic heterotrophic respiration, heterotrophic respiration, autotrophic respiration, no respiration, autotrophic respiration in vermiculite, and no respiration in vermiculite. Engelmann spruce seedlings and soil substrates were placed in specially designed respiration chambers and soil CO2 efflux measurements were taken four times over the course of a month. Soil microbial densities and root volumes were measured for each chamber after day thirty-three. Seedling presence resulted in significantly higher soil CO2 efflux rates for all soil substrates. Autotrophic respiration treatments were not representative of solely autotrophic soil CO2 efflux due to soil microbial contamination of autoclaved soil substrates; however, the mean autotrophic contributions averaged less than 25% of the total soil CO2 efflux. Soil microorganism communities were likely the primary contributor to soil CO2 efflux in simulated dormant conditions, as treatments with the greatest proportions of microbial densities had the highest soil CO2 efflux rates. Although this study is not directly comparable to field dormant season soil CO2 effluxes of Engelmann spruce forest, as snowpack is not maintained throughout this experiment, relationships, and metrics from such small-scale ecosystem component processes may yield more accurate carbon budget models.