Tropical peatlands are a major, but understudied, biophysical feedback factor on the atmospheric greenhouse effect. The largest expanses of tropical peatlands are located in lowland areas of Southeast Asia and the Amazon basin. The Loreto Region of Amazonian Peru contains ~63,000 km2 of peatlands. However, little is known about the biogeochemistry of these peatlands, and in particular, the cycling of carbon dioxide (CO2) and methane (CH4), and their responses to hydrometeorological forcings. To address these knowledge gaps, we established an eddy covariance (EC) flux tower in a natural palm (Mauritia flexuosa L.f.) swamp peatland near Iquitos, Peru. Here, we report ecosystem-scale CO2 and CH4 flux observations for this Amazonian palm swamp peatland over a two-year period in relation to hydrometeorological forcings. Seasonal and short-term variations in hydrometeorological forcing had a strong effect on CO2 and CH4 fluxes. High air temperature and vapor pressure deficit (VPD) exerted an important limitation on photosynthesis during the dry season, while latent heat flux appeared to be insensitive to these climate drivers. Evidence from light-response analyses and flux partitioning support that photosynthetic activity was downregulated during dry conditions, while ecosystem respiration (RE) was either inhibited or enhanced depending on water table position. The cumulative net ecosystem CO2 exchange indicated that the peatland was a significant CO2 sink ranging from −465 (−279 to −651) g C m−2 y−1 in 2018 to −462 (−277 to −647) g C m−2 y−1 in 2019. The forest was a CH4 source of 22 (20 to 24) g C m−2 y−1, similar in magnitude to other tropical peatlands and larger than boreal and arctic peatlands. Thus, the annual carbon budget of this Amazonian palm swamp peatland appears to be a major carbon sink under current hydrometeorological conditions.

中文翻译：

---

亚马逊棕榈沼泽泥炭地净生态系统二氧化碳和甲烷交换的水文气象敏感性

热带泥炭地是大气温室效应的一个主要但尚未得到充分研究的生物物理反馈因素。最大的热带泥炭地位于东南亚和亚马逊盆地的低地地区。亚马逊秘鲁的洛雷托地区包含约 63,000 平方公里的泥炭地。然而，人们对这些泥炭地的生物地球化学知之甚少，尤其是二氧化碳 (CO2) 和甲烷 (CH4) 的循环以及它们对水文气象强迫的响应。为了解决这些知识空白，我们在秘鲁伊基托斯附近的天然棕榈（Mauritia flexuosa Lf）沼泽泥炭地中建立了涡流协方差（EC）通量塔。在这里，我们报告了两年内与水文气象强迫有关的亚马逊棕榈沼泽泥炭地生态系统尺度的 CO2 和 CH4 通量观测。水文气象强迫的季节性和短期变化对 CO2 和 CH4 通量有很大影响。高气温和蒸汽压差（VPD）在旱季对光合作用施加了重要限制，而潜热通量似乎对这些气候驱动因素不敏感。来自光响应分析和通量分配的证据表明，在干燥条件下光合作用活动被下调，而生态系统呼吸 (RE) 则根据地下水位位置被抑制或增强。累积净生态系统 CO2 交换表明泥炭地是一个重要的 CO2 汇，范围从 2018 年的 -465（-279 至 -651）g C m-2 y-1 到 -462（-277 至 -647）g C m- 2 y−1 in 2019. 森林是 22 (20 to 24) g C m−2 y−1 的 CH4 来源，大小与其他热带泥炭地相似，但比北方和北极泥炭地大。因此，在当前的水文气象条件下，亚马逊棕榈沼泽泥炭地的年度碳收支似乎是一个主要的碳汇。