Temperature response of ex-situ greenhouse gas emissions from tropical peatlands: Interactions between forest type and peat moisture conditions
Temperature response of ex-situ greenhouse gas emissions from tropical peatlands: Interactions between forest type and peat moisture conditions
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DOI：
10.1016/j.geoderma.2018.02.029
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发表时间：
2018-08
期刊：
影响因子：
6.1
通讯作者：
S. Sjögersten;P. Aplin;V. Gauci;M. Peacock;A. Siegenthaler;Benjamin L Turner
中科院分区：
文献类型：
--
作者：
S. Sjögersten;P. Aplin;V. Gauci;M. Peacock;A. Siegenthaler;Benjamin L Turner
气候变暖很可能通过刺激微生物活动而增加热带湿地的二氧化碳（CO2）和甲烷（CH4）排放量，但人们对这些CO2和CH4排放量的温度响应幅度以及森林类型之间的温度响应差异知之甚少。这限制了对气候系统未来生态系统反馈的预测的准确性，这是一个严重的知识空白，因为这些热带湿地生态系统是温室气体排放的一个非常大的来源（例如，据估计，自然湿地的甲烷排放量的三分之二来自热带系统）。在这项研究中，我们实验操纵的温度和湿度条件下，从不同的森林类型在低地新热带泥炭地在巴拿马泥炭，并测量这如何影响异地CO2和CH4排放。在三种水分处理中，无氧CH 4产生（Q10= 6.8）和CH 4消耗（中温条件，Q10= 2.7）的温度响应最大，而CO2产生的温度响应较弱（Q10< 2）。CO2产量的最大温度响应被发现在淹没好氧条件下。CO2和CH4的净排放量最大的棕榈林在所有水分处理。此外，CH4排放的温度响应在主要植被类型之间存在差异，棕榈林的响应最强，当温度从20 ° C升高到35 °C时，通量从42 ± 25增加到2166 ± 842 ng CH4g−1h− 1。我们的结论是，CH4通量可能会受到更强烈的影响，更高的温度比CO2通量，但森林类型之间的响应可能会有很大的不同。在预测未来气候变化情景下的生态系统温室气体响应时，需要考虑森林类型（例如棕榈林与万年青阔叶林类型）之间的温度响应差异。
Climate warming is likely to increase carbon dioxide (CO2) and methane (CH4) emissions from tropical wetlands by stimulating microbial activity, but the magnitude of temperature response of these CO2and CH4emissions, as well as variation in temperature response among forest types, is poorly understood. This limits the accuracy of predictions of future ecosystem feedbacks on the climate system, which is a serious knowledge gap as these tropical wetland ecosystems represent a very large source of greenhouse gas emissions (e.g. two-thirds of CH4emissions from natural wetlands are estimated to be from tropical systems). In this study, we experimentally manipulated temperatures and moisture conditions in peat collected from different forest types in lowland neotropical peatlands in Panama and measured how this impacted ex-situ CO2and CH4emissions. The greatest temperature response was found for anaerobic CH4production (Q10= 6.8), and CH4consumption (mesic conditions, Q10= 2.7), while CO2production showed a weaker temperature response (Q10< 2) across the three moisture treatments. The greatest temperature response of CO2production was found under flooded oxic conditions. Net emissions of CO2and CH4were greatest from palm forest under all moisture treatments. Furthermore, the temperature response of CH4emissions differed among dominant vegetation types with the strongest response at palm forest sites where fluxes increased from 42 ± 25 to 2166 ± 842 ng CH4g−1h−1as temperatures were raised from 20 to 35 °C. We conclude that CH4fluxes are likely to be more strongly impacted by higher temperatures than CO2fluxes but that responses may differ substantially among forest types. Such differences in temperature response among forest types (e.g. palm vs evergreen broad leaved forest types) need to be considered when predicting ecosystem greenhouse gas responses under future climate change scenarios.